By D. Ismael. University of Wisconsin-Green Bay. 2019.
Toxic-shock syndrome: epidemiologic features buy cheap ketoconazole cream 15gm, recurrence best ketoconazole cream 15gm, risk factors purchase 15gm ketoconazole cream visa, and prevention order 15gm ketoconazole cream mastercard. Development of serum antibody to toxic shock toxin among individuals with toxic shock syndrome in Wisconsin. Epidemiologic analysis of group A Streptococcus serotypes associated with severe systemic infections, rheumatic fever, or uncomplicated pharyngitis. Evidence for superantigen involvement in severe group A streptococcal tissue infections. Streptococcal toxic shock syndrome: synthesis of tumor necrosis factor and interleukin-1 by monocytes stimulated with pyrogenic exotoxin A and streptolysin O. Toxin shock syndrome-associated staphylococcal and streptococcal pyrogenic toxins are potent inducers of tumor necrosis factor production. Streptococcal pyrogenic exotoxin B enhances tissue damage initiated by other Streptococcus pyogenes products. Clinical and microbiological characteristics of severe group A Streptococcus infections and streptococcal toxic shock syndrome. Differences in potency of intravenous polyspecific immunoglobulin G against streptococcal and staphylococcal superantigens: implications for therapy of toxic shock syndrome. The Eagle effect revisited: efficacy of clindamycin, erythromycin, and penicillin in the treatment of streptococcal myositis. Penicillin-binding protein expression at different growth stages determines penicillin efficacy in vitro and in vivo: an explanation for the inoculum effect. Potentiation of opsonization and phagocytosis of Streptococcus pyogenes following growth in the presence of clindamycin. Impact of antibiotics on expression of virulence-associated exotoxin genes in methicillin-sensitive and methicillin-resistant Staphylococcus aureus. Intravenous immunoglobulin therapy for streptococcal toxic shock syndrome—a comparative observational study. Intravenous immunoglobulin G therapy in streptococcal toxic shock syndrome: a European randomized, double blind, placebo controlled trial. Characterization of a strain of community-associated methicillin-resistant Staphylococcus aureus widely disseminated in the United States. Skin and soft-tissue infections caused by community-acquired methicillin-resistant Staphylococcus aureus. Necrotizing fasciitis caused by community associated methicillin resistant Staphylococcus aureus in Los Angeles. Invasive methicillin-resistant Staphylococcus aureus infections in the United States. Comparative activity of telavancin against isolates of community-associated methicillin-resistant Staphylococcus aureus. Telavancin versus vancomycin for the treatment of complicated skin and skin-structure infections caused by gram-positive organisms. Results of a double-blind, randomized trial of ceftobiprole treatment of complicated skin and skin structure infections caused by gram positive bacteria. Tribble Enteric Diseases Department, Infectious Diseases Directorate, Naval Medical Research Institute, Silver Spring, Maryland, U. Sometimes symptoms begin as early as on the plane ride home, sometimes not until weeks later. In either case, the patient becomes progressively ill, critically so, all the while unknowingly infecting others. The disease spreads, chaos is loosed, and only the timely insight of an awkwardly introverted yet surprisingly attractive physician stands between armageddon and the return of normalcy. Nonetheless, the likelihood of today’s critical care physician having to manage patients with a tropical infection is increasing, as international travel has increased from an estimated 25 million border crossings in 1950 to over 806 million crossings in 2005 (1). To better prepare travelers prior to their trips abroad, the discipline of travel medicine has been refined over the past 25 years, with an increasing reliance upon evidence-based data and the recent publication of practice guidelines (2). This information assists the physician in determining not only what vaccines or prophylactic regimens may help prevent infection in the traveler, but also stresses the importance of safety awareness and environmental risk avoidance. It is no surprise, then, that each year four million travelers returning from developing countries become ill enough that medical intervention is required either en route or upon return home (4). That is not to say there are four million cases of Ebola or African trypanosomiasis every year, but how can the clinician know what illnesses are being seen, and more importantly, which to consider more likely in their patients? Established in 1995, it now comprises 41 travel or tropical medicine clinics (16 in the United States, 25 in other countries representing all continents) that not only report what diagnoses are seen in their facilities, but additional invaluable data such as time to presentation of illness, geographic exposures, adherence to prophylactic measures, etc. With now more than a decade of surveillance information available, it has been shown that febrile illness, dermatologic disorders (especially insect bites), and acute/chronic diarrheal illnesses comprise almost 70% of all travel-related illness (4). An analysis of 6957 travelers with fever revealed that malaria (21%), acute diarrheal disease (15%), respiratory illness (14%), and dengue (6%) were the most commonly identified etiologies (6). Time to presentation can be helpful to the clinician when generating a differential diagnosis (see Table 1). It is helpful to realize that the familiar adage “common things are common” applies also to travel medicine. In a review of 25,023 patients within the GeoSentris database, there were no reported cases of travel-related anthrax, yellow fever, primary amebic meningoencephalitis, poliomyelitis, Rift Valley fever, tularemia, murine typhus, tetanus, diphtheria, rabies, Japanese encephalitis, or Ebola (4). In the same report, of 17,353 patients, only one case each of the following infections was identified: Angiostrongylus cantonensis, hantavirus, cholera, melioi- dosis, Ross River virus, legionellosis, meningococcal meningitis, and African trypanosomiasis. If any of these diagnoses is suspected, an infectious diseases consultation is recommended. As malaria is the single most common life-threatening infection in returning travelers (Table 2), it will be emphasized in this chapter. Other critical care infectious disease syndromes to be Table 2 General Considerations in Potentially Infected Critically Ill Returning Travelers Diagnostic consideration Comments Make accurate traveler- and itinerary-specific Obtain detailed history of sites visited, activities, and potential risk assessment. Incubation periods: short (<10 days); intermediate (10–14 days); prolonged (>21 days) A minimum period of 5–7 days before considering malaria. Narrow the differential diagnosis using clinical progression and specific findings (i. Always consider and perform diagnostic testing to evaluate for malaria if a traveler has been in a malarious region with an appropriate incubation period. Data from 1997–2002 collected through the GeoSentinel global sentinel surveillance identified malaria in 3. Patients with falciparum malaria were more likely to have traveled to sub-Saharan Africa (89%), with the majority (80%) presenting within four weeks of their return. Several important features are noted among those patients who died from their infection. These include: insufficient or inappropriate malaria chemoprophylaxis (90%) and delay in diagnosis and/or effective therapy (40%). Deaths were considered preventable in 85% of cases and were commonly attributed to patient-related decisions/actions and/or contributing medical errors (11). The current recommendations for malaria prophylaxis take into consideration regional antimalarial drug resistance (13). And so, as a result of our population’s increasing travel to malaria-endemic areas as well as oftentimes inadequate adherence to prescribed chemoprophylaxis, it is increasingly likely that today’s critical care physician will encounter patients with malaria. Unfortunately, there are no historical or physical findings pathognomonic for malaria. Therefore, malaria cannot be ruled out by history or physical examination alone (11,19,20). Falciparum malaria often presents without the classic features of cyclical fever, chills, and diaphoresis (21). When the diagnosis of malaria is suspected, examination of Giemsa or Wright-stained peripheral blood thick and thin smears should be performed. Thick smears are more sensitive (larger volume of blood), but are also more difficult to interpret. Thin smears aid in species identification, and higher percentage parasitemias may be evident even to the novice. Venous blood or blood from a peripheral stick is applied to the test card, and within 15 minutes a negative or positive result is apparent. However, serial thick and thin smears are still recommended (although a negative rapid assay, even if falsely negative, likely excludes significant parasitemia). A positive assay should also be followed by examination of the Tropical Infections in Critical Care 325 peripheral smear for confirmation and in order to determine both the species (possibly more than one) and the level of parasitemia. Nonmicroscopic immunochromatographic tests such as 1 the Binax Now Malaria Test assay are rapid and simple to perform.
Management: The pressure gradient across the aortic arch was significant resulting in upper body hypertension ketoconazole cream 15gm mastercard. Relief of coarctation of the aorta at this age can be per- formed effectively and safely through balloon dilation and typically with stent placement to reduce the possibility of restenosis after initial improvement buy ketoconazole cream visa. Findings at the cardiac catheterization: Cardiac catheterization revealed a pressure gradient of 45 mmHg across the aortic arch purchase ketoconazole cream toronto. The areas proximal and distal to the site of coarctation were 22 and 23 mm respectively purchase ketoconazole cream now. The systolic pressure gradient across coarctation dropped to 8 mmHg post stenting and angioplasty. Angiography after the balloon dilation showed good position of stent with adequate aortic arch patency (Fig. Results: Echocardiography performed the next morning showed stent in good position with no significant pressure gradient across the aortic arch. On follow up 3 months after the procedure, she was found to be doing very well with no cardiovascular symptoms and no claudication. The latter is a communication between the 2 atria due to patency of a normal in-utero structure caused by the space between the 2 membranes forming the atrial septum. Hanrahan Incidence Defects in the interatrial septum are a common congenital heart defect. As an isolated anomaly, atrial septal defects are the fifth most common congenital heart defect, com- prising 6% of all lesions. Pathology There are many types of atrial septal defects, classified according to location of defect. These include: • Secundum atrial septal defect: the defect is in the foramen ovale membrane, which is the central portion of the atrial septum (Fig. These are the most common type of atrial septal defects and most likely to close spontaneously. Secundum atrial septal defects are more common in females who tend to be tall and thin. The first and more com- mon is when the defect is close to the superior vena cava junction with the right atrium. This is frequently associated with abnormal drainage of right upper pul- monary vein to the right atrium (partial anomalous pulmonary venous return). The second type is when the sinus venosus atrial septal defect is close to the inferior vena cava junction with the right atrium. Defect in this region results in secundum atrial septal defect (white arrow) which is the most common type of atrial septal defect. Mixing of well- saturated blood from the pulmonary veins with that of the desaturated blood from the systemic veins occurs in this anomaly leading to mild cyanosis. Pathophysiology Abnormal communications between the right and left cardiac chambers or vessels create an opportunity for blood to move from one side to the other. Left to right shunting of blood will result in the reduction of cardiac output to the body (Qs) and increase in cardiac output to the pulmonary circulation (Qp) (Fig. The pulmonary vascular resistance is significantly less than the systemic vascular resistance, therefore, any abnormal communication between the left and right sides of the heart will result in left to right shunting. In this diagram, 6 l/min/m2 of blood return from the pulmonary circulation, 4 l/min/m2 cross the atrial septal defect to go to the pulmonary circulation while the remaining 2 l/min/m2 go to the systemic circulation. In this scenario, the pulmonary blood flow to systemic blood flow ratio is 6:2 or 3:1. The greater this ratio, the more is the pulmonary blood flow and consequently, the worse is the extent of congestive heart failure 94 Ra-id Abdulla and A. Hanrahan Increase in blood flow to the lungs will eventually lead to pulmonary edema. Drop in systemic cardiac output tends to be marginal since it is minimized by increasing the blood volume through water retention. Most of the symptoms noted in atrial septal defect, such as shortness of breath and easy fatigability are a result of pulmonary edema. Increased pulmonary blood flow over several decades will eventually cause progressive damage to the pulmonary vasculature wall resulting in pulmonary vascular obstructive disease in the third or fourth decades of life. Clinical Manifestations Small and moderate size atrial septal defects are typically asymptomatic. Larger defects result in pulmonary edema manifesting as easy fatigability and shortness of breath. Only very large defects result in significant congestive heart failure and failure to thrive. On examination there is a hyperactive precordium with a prominent right ventricular impulse due to right ventricular dilation. Second heart splitting is fixed throughout respiration due to increased blood flow through the pulmonary valve causing delay in pulmonary valve closure regardless of respiratory cycle. A systolic ejection (crescendo– decrescendo) murmur is heard at the left upper sternal border due to increase in blood flow across the pulmonary valve. In larger atrial septal defects, an early diastolic murmur is heard at the left lower sternal border due to increased blood flow across the tricuspid valve (Fig. S1 first heart sound, S2 second heart sound, A aortic valve closure, P pulmonary valve closure. Increase in blood flow across the pulmonary valve results in a systolic ejection murmur, while the increase in blood flow across the tricuspid valve causes a middiastolic murmur. Unlike pulmonary stenosis, the systolic murmur is not preceded by a systolic click. The second heart sound is fixed in its splitting (through respiration) due to the excessive pulmonary blood flow and the need for the pulmonary valve to stay open longer throughout respiration 6 Atrial Septal Defect 95 Diagnosis Chest X-Ray Prominent pulmonary vasculature due to left to right shunting is present. In addition, increase in blood flow through the right heart will cause right atrial and right ventricular dilation manifesting as cardiomegaly on chest X-ray; how- ever, this is noted only when there is significant extent of left to right shunting. Excessive pulmonary blood flow may cause dilation of the main pulmonary artery manifested as prominent pulmonary artery at the midleft cardiac silhouette border (Fig. Left to right shunting causes increase in blood volume in the right heart resulting in cardiomegaly. The engorged pulmonary vasculature could be seen on chest X-ray as prominent pulmonary vessels in the hilar region as well as being able to see pulmonary vessels in the peripheral lung fields 96 Ra-id Abdulla and A. Hanrahan Electrocardiograph Right atrial and right ventricular dilation/hypertrophy may be noted. Right atrial enlargement manifests as tall P waves (taller than 2 mm in children and 3 mm in adolescents and adults). Right ventricular dilation may lead to leftward deviation of the interventricular septum. In adults with poor echocardiography window, transesophageal echocardiography is used to visualize the atrial septum to confirm diagnosis (Fig. Cardiac Catheterization Cardiac catheterization is not required for diagnostic purposes since diagnosis can be made by echocardiography. However, cardiac catheterization is performed in patients with secundum atrial septal defect for therapeutic purposes. In this figure, blood is shunting across the atrial septal defect from left atrium to right atrium toward the probe, therefore, red in color Treatment Most patients with atrial septal defect do not require medical treatment for congestive heart failure due to the limited impact of small to moderate increase in pulmonary blood flow. On the other hand, patients with larger defects and excessive pulmonary blood flow may benefit from anticongestive heart failure medications such as diuretics. Inotropic agents, such as digoxin and afterload reducing agents, are rarely required. Closure of atrial septal defect is determined by the type of the defect and its size. Small (less than 5 mm in diameter) and medium (5–8 mm in diameter)-sized secundum defects diagnosed during early infancy tend to close spontaneously, often in the first 2 years of life. If at 2 years of life the defect is still present, closure could be considered through the use of occluding devices in the cardiac catheteriza- tion laboratory (Fig. Sinus venosus and primum atrial septal defects do not close spontaneously and will require surgical repair which could be performed around 1 year of age. Surgical repair is the only modality of treatment for sinus venosus and primum atrial septal defects since they are not amenable to device 98 Ra-id Abdulla and A. Note that in this type of device (Amplatzer) there are two discs, right and left- sided discs which hold the device in place across the atrial septal defect closure due to lack of circumferential atrial septal wall which are used to anchor devices after deployment.
Waterborne Diseases ©6/1/2018 221 (866) 557-1746 Because contamination of samples from coliphage during the analytical procedure is highly probable (Francy and others generic ketoconazole cream 15gm mastercard, 2000) buy genuine ketoconazole cream on-line, a negative control of host and sterile buffered water is run concurrently with each batch of samples purchase 15gm ketoconazole cream fast delivery. In addition discount ketoconazole cream 15gm otc, to ensure that the method is being executed properly, a positive-control sewage sample is run with each batch of samples. A laminar flow safety hood is recommended for processing the samples for coliphage analysis. Alternatively, a separate coliphage room may be established to discourage laboratory contamination during the analytical process. An ultraviolet light is installed and operated for 8 hours every night in the safety hood or coliphage room to reduce contamination. Waterborne Diseases ©6/1/2018 222 (866) 557-1746 Disinfection Byproduct Regulations Drinking water chlorination has contributed to a dramatic decline in waterborne disease rates and increased life expectancy in the United States. Largely because of this success, many Americans take it for granted that their tap water will be free of disease-causing organisms. In recent years, regulators and the general public have focused greater attention on potential health risks from chemical contaminants in drinking water. It is now recognized that all chemical disinfectants form some potentially harmful byproducts. Thus, it is important that disinfection not be compromised in attempting to control such byproducts. Most water systems are meeting these new standards by controlling the amount of natural organic matter prior to disinfection, while ensuring that microbial protection remains the top priority. For this reason, The American Academy of Microbiology (Ford and Colwell, 1996) has recommended, the health risks posed by microbial pathogens should be placed as the highest priority in water treatment to protect public health. A report published by the International Society of Regulatory Toxicology and Pharmacology (Coulston and Kolbye, 1994) stated “The reduction in mortality due to waterborne infectious diseases, attributed largely to chlorination of potable water supplies, appears to outweigh any theoretical cancer risks (which may be as low as zero) posed by the minute quantities of chlorinated organic chemicals reported in drinking waters disinfected with chlorine. Coagulation and Clarification Most treatment plants optimize their coagulation process for turbidity (particle) removal. However, coagulation processes can also be optimized for natural organic matter removal with higher doses of inorganic coagulants (such as alum or iron salts), and optimization of pH. Absorption Activated carbon can be used to absorb soluble organics that react with disinfectants to form byproducts. Membrane Technology Membranes, used historically to desalinate brackish waters, have also demonstrated excellent removal of natural organic matter. Membrane processes use hydraulic pressure to force water through a semi-permeable membrane that rejects most contaminants. Much less is known about the byproducts of these alternatives than is known about chlorination byproducts. Furthermore, each disinfection method has other distinct advantages and disadvantages. Waterborne Diseases ©6/1/2018 225 (866) 557-1746 Waterborne Diseases ©6/1/2018 226 (866) 557-1746 Common Water Quality and Sampling Questions and Review These statements will be more explained in the previous chapters. The regulations call for ao minimum of five samples for the month from any system that has positive sample results. Small systems that take only one sample per month have to take four (4) repeats when they get a total coliform positive test result. If any system has to take repeat samples, it must also take a minimum of five (5) routine samples the following month. Small systems that normally take less than 5 samples/month will have to increase the number to 5 samples. They can return to normal sampling schedules the following month if no repeats are required. Proper sampling techniques are extremely important in obtaining accurate water quality information. An improperly taken coliform sample may indicate bacteriological contamination of your water when the water is actually safe. The sampling point must be a faucet from which water is commonly taken for public use. It should not be a faucet that leaks, permitting water to run over the outside of the faucet. If an outside faucet must be used, disconnect any hoses or other attachments and be sure to flush the line thoroughly. Do not dip the bottle in reservoirs, spring boxes or storage tanks in order to collect the sample. Gallons per minute- Million Gallons a Day - Total Trihalomethanes – Pounds Per Square Inch –Haloacetic acids - Nephelometric turbidity unit -Milligrams Per Liter 4. Milligram per liter: Milligram per liter of substance and part per million are equals amounts in water. One ppb represents one microgram of something per liter of water (ug/l), or one microgram of something per kilogram of soil (ug/kg). Parts per million (ppm) or Milligrams per liter (mg/l) - one part per million corresponds to one minute in two years or a single penny in $10,000. Parts per billion (ppb) or Micrograms per liter - one part per billion corresponds to one minute in 2,000 years, or a single penny in $10,000,000. Parts per trillion (ppt) or Nanograms per liter (nanograms/l) - one part per trillion corresponds to one minute in 2,000,000 years, or a single penny in $10,000,000,000. Presence-absence Test: Presence-Absence Broth is used for the detection of coliform bacteria in water treatment plants or distribution systems using the presence-absence coliform test. Physical Characteristics of Water: A characteristic of water defined by the temperature, turbidity, color, taste, and odor of the water. Routine Sample: Samples collected on a routine basis to monitor for contamination. Repeat Sample: Short answer… Samples collected following a ‘coliform present’ routine sample. The number of repeat samples to be collected is based on the number of routine samples you normally collect. Waterborne Diseases ©6/1/2018 228 (866) 557-1746 Anytime a microbiological sample result comes back positive, indicating the presence of total or fecal coliform/ E. The two samples must be taken upstream and downstream of the original site (within five service connections). These repeat samples must be taken within 24 hours of notification of positive results. The regulations also state that when repeats are taken the minimum number of samples is raised to five for the month. A system that collects just one sample a month must collect four repeat samples, when the sample is positive, in order to have five samples as required. Whenever a system has to take repeat samples, a minimum of five routine samples must also be submitted the following month. This is only an issue for systems that normally turn in four or fewer samples each month. If the five samples are negative the system can return to its normal sampling schedule the next month. Small systems that have fewer than four sampling sites have a problem complying with the “upstream and downstream” aspects of the repeat sampling requirements. In this case, samples should be taken at as many separate sites as possible and then wait a minimum of 2 hours before resampling enough sites to get the required number of samples. Treatment technique: An enforceable procedure or level of technical performance which public water systems must follow to ensure control of a contaminant. Action level: The level of lead or copper which, if exceeded, triggers treatment or other requirements that a water system must follow. What does the membrane filter test analyze with regards to bacteriological sampling? Membrane Filter Technique: A standard test used for measuring coliform numbers (quantity) in water is the membrane filter technique. This technique involves filtering a known volume of water through a special sterile filter. These filters are made of nitrocellulose acetate and polycarbonate, are 150 μm thick, and have 0. A grid pattern is printed on these filter disks in order to facilitate colony counting. The filter is then carefully removed, placed in a sterile petri plate on a pad saturated with a liquid medium, and incubated for 20-24 hours at 37°C.
First ketoconazole cream 15gm mastercard, the mutual internal and external meridians are observed to be closely related to their distribution in the peripheral nerves best 15gm ketoconazole cream. These distributions correspond to the parlance of “Fu-organs following to Zang-organs and meridians of Fu-organs going along superficial and external” order ketoconazole cream 15 gm otc. One can observe the ulnar and medial antebrachial cutaneous nerve distributed along both the meridians order 15gm ketoconazole cream with visa. The branches of the medial antebrachial cutaneous nerve distributed along both the meridians, and many acupoints of the two meridians are observed to be related to the palmar interosseous nerve of the median nerve in the deep layer. On the head, both the facial and auriculotemporal nerves are distributed on the two meridians. Both the saphenous nerve and superficial peroneal nerves are distributed on the two meridians. In addition, Kidney Meridian of Foot-Shaoyin and Bladder Meridian of Foot-Taiyang are observed to be related to the internal and external meridian, respectively, comprising tibial-nerve distribution. Thus, diseases related to the internal meridian can be treated using both internal and external meridians. On the other hand, the “external” diseases can also be treated using external and internal meridians. Second, the relationship between the distribution of Shu and Mu points, and their correlative viscera are observed to be closely associated with the distribution 64 2 Neuroanatomic Basis of Acupuncture Points of the peripheral nerves. Shu points on the back and nape parts, and Mu points on the chest and abdomen parts can be differentiated into Yin and Yang: Mu points belong to Yin, and the Shu points belong to Yang. This shows that the points and their corresponding internal organs have an identity in the neural segments. The alignments of the acupoints on the ventral and dorsal trunk present the neurotaxis are shown in Fig. The characteristic alignments of the acupoints of the eight meridians are as follows: Figure 2. Note that the connection between the meridian point and viscera is closely related to the segmental innervations and the convergence of somatic and autonomic nerves at the same spinal segments (modified from figures of Yan, 1988). The alignments of the acupoints are very identical with the distribution of the anterior cutaneous branches of the thoracic nerve. As the lateral branch of the anterior cutaneous branches of the cutaneous nerve on the abdomen is shorter, the acupoints of the 67 Acupuncture Therapy of Neurological Diseases: A Neurobiological View three meridians are observed to lie nearer to the midline of the abdomen. However, when the three meridians go up to the thorax, the lateral branches of the thoracic nerves extend longer, and owing to the enlargement of the thoracic cage, the alignment of the acupoints of the three meridians move away from the midline laterally. Apparently, alignments of the acupoints on the trunk are very identical with the segmental innervation. The alignments of the acupoints on the four limbs is associated with the nerve segments. As the nerve segments of the four limbs are the extension of the primitive nerve segments along the longitudinal axis of the limbs, unlike the obvious segmental characters of the nerve segments on the trunk, every meridian on the limbs are located at one or two nerve segments. For example, the Lung Meridian of Hand-Taiyin is distributed along the radial to the upper limbs, which includes the spinal segment of C5 6. The Heart Meridian of Hand-Shaoyin is distributed along the ulnar to the upper limbs, corresponding to the spinal segment of T1. The Pericardian Meridian of Hand-Jueyin is distributed intermediately, including the spinal segment of C7 8. Another example is the distribution of acupoints of the Heart Meridian of Hand-Shaoyin from the aspects of the nerve segments. This meridian is situated just at the segment of the upper thoracic spinal cord (T1 3), and the sensory fibers of the somatic nerves of the medial upper limbs also enter the dorsal horn of the upper thoracic spinal cord. The primary center of the sympathetic nerve of the heart is also located at the upper thoracic spinal cord. As both these sensory fibers and sympathetic nerves converge at the dorsal horn of the upper thoracic spinal cord, acupuncturing the acupoints of the Heart Meridian of Hand-Shaoyin can affect the functioning of the heart through the segment of the upper thoracic spinal cord. The relationship between the therapeutic efficacy and particular acupoints further shows that the meridians are closely related to the neural segments. For instance, the points of the Heart Meridian of Hand-Shaoyin may be used to treat diseases of the heart, lung, and trachea. The same meridian passes through the medial aspect of the tip of the little finger, and the medial aspect of the forearm and the chest. The skin of these areas where the meridian passes is controlled by the first-third neural segments of the thoracic nerves. This indicates that these areas and the heart, lung, and trachea are under the domination of the same neural segments. Another example is the long branches of the intercostal nerve that descend for several segments. According to the orientation of the sensation of needling and the range of indications of the acupoints, there exists considerable coherency between the segmental nerve distribution of the acupoints and that of the organs. These nerve segments are also vegetal nerve segments that dominate the celiac and pelvic organs. The traits of the meridian may be related to its special morphological structure, which might explain the possibility of the treatment of the internal-organ diseases by puncturing or moxibusting the superficial acupoints. The relationship between the meridian-points and the peripheral nerves is different from that between the body trunk and limbs. On the body trunk, the nerves are segmental and arranged almost annularly, and occasionally, are vertical. This phenomenon may interpret the reason for the radiating nature of the needling sensation along the meridian path. Based on the overlapped and anastomosed relationship between the segments of the afferent nerve of the visceral organs and some special acupoints, we may at least partially explain the aspect of the morphologic basis of stimulating the acupoints to treat diseases of the visceral organs. Other experiments (Tao and Li 1993; Tao and Ren 1994) also validated the phenomena that afferent fibers of the body surface and the relative viscera converge at the same neuron. Using double-labeling technology, researchers (Tao and Ren 1995) found double-labeled cells at T2 5. These phenomena imply that the effect of acupuncture on the visceral function may occur at the lower center (spinal cord), and that the sensory impulse 70 2 Neuroanatomic Basis of Acupuncture Points of the acupoints or the peripheral nerves activated by acupuncture could affect the sensation and function of the viscus through the efferent branches of the axons. In addition, by using the methods of neural degeneration and lesion techniques, researchers also found that the nucleus of the brainstem, hypothalamus, and cortex play an important role in the relationship between the meridian-point and viscus. For structural feature of acupoint Rongquan (K-1), there were many receptors at side of muscular mantle and fiber, such as free nerve ending, muscular spindle, and so on. Collectively, the area of an acupoint is observed to contain free nerve ending, Vater-Pacini corpuscles, and muscle spindle. Furthermore, the acupoints and meridians are observed to be closely related to the peripheral nerves. These observations suggest that the sensory fibers of the somatic nerve serve as an afferent pathway of acupuncture. On the other hand, many studies show that the acupuncture could induce activation of the internal organs. In 1978, Toda and Ichioka reported that type Ċ afferent fibers were sufficient for acupuncture analgesia in rats. In addition, Pomeranz (1986) also found that type Ċ afferent fibers were adequate to produce acupuncture analgesia. Some researchers believed that the acupoint maps were essential for localizing the sites where the best De-Qi could be achieved (i. Lu (1983) showed that type Ċ and ċ afferent fibers were important for acupuncture analgesia in rabbits and cats because diluted procaine (0. In 1985, Wang et al carried out some observational experiments on human subjects using direct microelectrode recordings from single fibers in the median nerve, and performed acupuncture on the distal side. They observed that during De-Qi, numbness was related to the activation on type Ċ muscle afferent fibers; heaviness, distension, and aching were owing to the activation of type ċ fibers; and soreness was related to the activation of type Č non-myelinated fibers. The acupuncturists also noticed that when the patient got the De-Qi sensation, the muscle grabbed the needle. Although there is still disagreement on the relationships between the afferent effect of the acupuncture and the fiber type of the somatic nerves (Zhu 1998), anatomical and electrophysiological evidence lead us to the conclusion that afferent fibers of type Ċ and ċ are responsible for transmitting the acupuncture signal.