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Biomedical subjects

M H Snow

Publications and source records attributed to M H Snow.

At least 19 recordsLinked to original sources

HIV viral suppression in the era of antiretroviral therapy.

Altogether 42 million people worldwide have been infected with HIV, and 12 million have died over the last 20 years. Effective antiretroviral therapy has lead to sustained HIV viral suppression and immunological recovery in patients who have been infected with the virus. The incidence of AIDS has declined in the Western world with the introduction of effective antiretroviral therapy. Questions on When to start treatment?, What to start with?, How to monitor patients?, remain heavily debated. Adherence to antiretroviral treatment remains the cornerstone of effective treatment, and failure to adhere is the strongest predictor of virological failure. Long term therapy can lead to metabolic complications. Resource poor countries are dealing with difficult issues such as mother to child prevention of HIV transmission. Other treatment options are now available, with the recent introduction of fusion inhibitors, second generation non-nucleoside reverse transcriptase inhibitors, and nucleotide reverse transcriptase inhibitors to clinical practice.

Anti-HIV Agents↗

Oral cancer, fever of unknown origin, and listeriosis.

Listeriosis is a rare cause of fever of unknown origin in patients with oral cancer. We report two patients who, because of pain and discomfort, ate large quantities of soft cheeses; this caused listeriosis and fever. Both cases responded to high doses of amoxycillin.

Amoxicillin↗

Pneumocystis carinii pneumonia after thoracic duct ligation and leakage.

A case of Pneumocystis carinii pneumonia was induced through immunosuppression following thoracic duct ligation. The patient initially presented with an esophageal adenocarcinoma, which was totally resected. She is human immunodeficiency virus-negative and not undergoing immunosuppressive treatment.

CD4 Lymphocyte Count↗

Activity-induced fiber regeneration in rat soleus muscle.

In an attempt to understand why muscle recovery is limited following atrophy due to limb immobilization, satellite cell activity and muscle fiber regeneration were analyzed in rat soleus muscles. Adult rat hindlimbs were immobilized in plaster casts for a period of two to ten weeks. Soleus muscles were examined by electron microscopy for evidence of fiber degeneration or regeneration, and to quantify satellite cell nuclei. Immunocytochemical localization of embryonic myosin was used to identify regenerating myofibers. Soleus muscle wet weight to body weight ratios for the casted muscles significantly decreased over the 10-week immobilization period. The casted muscles displayed ultrastructural evidence of minor fiber damage, including myofibrillar atrophy, Z-disc disruption, and abnormal triadic junctions. No ultrastructural evidence of regeneration was seen in the casted animals. The number of satellite cells in the casted muscles significantly decreased from 6.4% to 3. 3% by eight to 10 weeks of immobilization. Approximately 1.0% of extrafusal fibers in the control soleus muscles appeared to be regenerating since they expressed embryonic myosin and were of a small diameter, while in casted muscles, only 0.1% of the fibers were embryonic myosin-positive. Following release from immobilization, a reappearance of embryonic myosin-positive fibers was noted within four days of renewed activity. In contrast to control muscles, embryonic myosin-positive fibers in the recovery muscles included both small and large diameter fibers. Subtle changes in functional activity influence muscle damage and subsequent myofiber regeneration. Reduced activity reduces muscle fiber regeneration, while increased activity, as seen by increased hindlimb weight bearing and return to normal activity following immobilization, increase regenerating fibers and also the expression of embryonic myosin in adult fibers.

Aging↗

Primary tuberculosis of the posterior oropharyngeal wall.

We report a case of primary tuberculosis of the posterior oropharyngeal wall presenting with sore throat, fever and malaise. Pharyngeal tuberculosis is rare and usually occurs with primary pulmonary disease. Primary disease has been reported in small numbers in the nasopharynx and palatine tonsil but never before, to our knowledge, in the posterior oropharyngeal wall.

Adult↗

An indolent penile herpetic ulcer in a patient with previously undiagnosed human immunodeficiency virus infection.

We report a case of an atypical penile herpetic ulcer in a man with previously undiagnosed human immunodeficiency virus (HIV) infection. Swabs of the lesion were negative for herpes simplex virus (HSV) by culture and electron microscopy. However, histopathology of biopsy material showed characteristic herpetic multinucleate giant cells. Immunochemistry using polyclonal antibodies was positive for HSV1 and HSV2. The lesion completely resolved after treatment with aciclovir and the patient subsequently tested positively for HIV antibodies.

Adult↗

The role of disclosure in coping with HIV infection.

A qualitative investigation was conducted to explore the role of disclosure in HIV infection. Forty homosexual and bisexual men completed a short demographic questionnaire and participated in a one-to-one, semi-structured interview. The interview was designed to address a variety of personal, interpersonal and organizational issues related to their HIV status and participants were invited to talk about their personal experiences from immediately prior to their diagnosis to the time of the interview. The results from the interviews are presented in three sections: immediately post-diagnosis, asymptomatic phase and symptomatic/AIDS phases. The data revealed that disclosing one's HIV status was an acute and recurrent stressor. Immediately post-diagnosis, individuals were more likely to adopt a policy of non-disclosure and this provided them with an opportunity to come to terms with their diagnosis before having to contend with the reactions of others. After this phase, there was evidence that individuals increasingly used disclosure as a mechanism for coping with the disease. Disclosure of one's status was used to increase both practical and emotional support, share responsibility for sex and to facilitate self-acceptance of one's condition. The results from this investigation revealed that disclosure has a dual role in HIV infection acting as both a stressor and a mechanism by which individuals contend with their infection.

Acquired Immunodeficiency Syndrome↗

Greater emotional distress is associated with accelerated CD4+ cell decline in HIV infection.

An investigation was conducted to explore the relationship between emotional distress and HIV progression. One hundred twenty-five homosexual, HIV-positive males participated in a 12-month longitudinal investigation. Psychosocial data were collected at 6-month intervals and CD4+ data were collected from diagnosis to the end of the investigation. Principal component analyses were performed initially to identify factors of emotional distress and health status. In addition, CD4+ reliability assessments were performed to ensure the validity of the prognostic assessments made. As a result of these analyses, 47 individuals were eligible for the main analyses. The results from a stepwise regression revealed that disease progression was significantly predicted by CD4+ count at diagnosis (32% of variance) and emotional distress (17% of variance), but was unrelated to subjective perceptions of health. The data suggest that some of the variability in HIV progression can be attributed to emotional distress.

Adult↗

Effects of supplemental instruction on mean test scores and failure rates in medical school courses.

PURPOSE: To determine whether supplemental instruction offered to first-year medical students reduces the number of examination failures. METHOD: A student-run, optional, supplemental-instruction program called the Medical Scholars Program (MSP) was offered at no cost to all first-year students at the University of Southern California School of Medicine in 1994-95. Supplemental instruction was offered in a small-group format in biochemistry, gross anatomy, microanatomy, and physiology. Weekly two-hour sessions were conducted by second-year medical students during the first trimester of the year-1 curriculum. Mean test scores and failure rates for students considered academically at risk and those not at risk were compared between the class entering in 1994 and the classes matriculating during the preceding three years. At-risk students were defined as those with a total Medical College Admission Test score below 26 and a science grade-point average below 3.0. Comparisons were performed using two-tailed t-tests and chi-square tests. RESULTS: Statistically significant increases in mean test scores were achieved on most examinations by the class exposed to the MSP. Failure rates for at-risk students decreased by 46% during the year the MSP was offered. CONCLUSION: Supplemental instruction can significantly improve student performance and therefore retention, particularly among at-risk students.

California↗

Overwhelming pneumoccoccal sepsis in two patients splenectomised more than ten years previously.

Asplenic individuals are known to be at a higher risk of developing serious and occasionally fatal sepsis. Prophylactic measures are generally recommended for the first few years post-splenectomy. We report two cases of severe Pneumococcal Sepsis occurring more than 10 years post-splenectomy leading to prolonged hospitalisation and long term morbidity and suggest that Prophylactic Penicillin should be taken life-long.

Adult↗

Presence of embryonic myosin in normal postural muscles of the adult rat.

Indirect immunofluorescence was used to localize embryonic myosin heavy chains in soleus, adductor longus, tibialis anterior, plantaris, and extensor digitorum longus muscles of 6-month-old rats. A monoclonal antibody (2B6), specifically recognizing rat embryonic myosin, was applied to unfixed, transverse, frozen sections. The number of embryonic myosin-positive (EMP) extrafusal fibers was expressed as a percentage of the total number of fibers. EMP extrafusal fibers were only seen in the soleus and adductor longus muscles, both postural muscles. Approximately 1% of the soleus muscle fibers appeared positively stained for embryonic myosin. The majority of such fibers had a small diameter (< 500 mu2), appeared intensely fluorescent, and typically contained central nuclei. Re-expression of embryonic myosin due to spontaneous fiber denervation is not a likely factor in this study, since alpha-bungarotoxin and N-CAM localization were restricted to the motor end-plate region of EMP fibers. Since embryonic myosin was shown to disappear in all normal-sized myofibers by 2 to 3 months of age, the results suggest that the EMP extrafusal fibers seen in postural muscles of 6 to 12-month-old animals are regenerating myofibers. We speculate that a small number of muscle fibers may be regenerating in normal, adult postural muscles, in response to fiber damage possibly caused by excessive recruitment or overloading.

Animals↗

Mortality and survival trends in patients with AIDS in north east England from 1984-1992.

OBJECTIVE: to study trends in mortality and survival in patients with AIDS attending an ID unit. METHOD: retrospective analysis of patients developing an AIDS-defining illness between April 1984, and November 1992. Survival was analysed by calculation of survival product-limit. RESULTS: 71 patients were analysed (including four women), 23 of whom are still alive. Pneumocystis carinii pneumonia (PCP) was the most frequent AIDS-index diagnosis: n = 36 (51%); 24 of these patients have died. HIV encephalopathy was the most frequent diagnosis at death; n = 16 (22.5%), followed by mycobacterial infection; n = 11 (15.5%), and PCP and CMV infection, each occurring in 10 (14%). One-, 2- and 3-year survival probabilities for patients with AIDS before 1987 were 0.46, 0.15 and 0 compared with probabilities of 0.63, 0.5 and 0.3 in those diagnosed after 1987; log rank -P < 0.01. One- and 2-year survival probabilities in patients who received at least 3 months' zidovudine (AZT) therapy were 0.76 and 0.53 in those who are still alive compared with 0.55 and 0.33 in the deceased, while values for deceased AZT-naive patients were 0.29 and 0.1; -P < 0.01. Thirteen (27%) deaths occurred within 2 months of an AIDS-index disease. In 10 patients this was their first presentation to the department. PCP accounted for 8 (61%) of these deaths. CONCLUSIONS: survival in patients with AIDS has increased since 1987, when AZT was introduced. Early AIDS-related deaths are frequent in patients who have had no prior medical care. This has implications for education and provision of care in individuals with asymptomatic HIV infection.

AIDS Dementia Complex↗