Search PubMedSearch

Biomedical subjects

S Allen

Publications and source records attributed to S Allen.

At least 37 records · Page 2Linked to original sources

Incidence of hairy cell leukemia, mycosis fungoides, and chronic lymphocytic leukemia in first known HTLV-II-endemic population.

Unlike human T cell leukemia-lymphoma virus type I (HTLV-I), HTLV-II has not been convincingly linked to a malignancy. In the first 10 months of serologic screening for HTLV-I/II among blood donors in New Mexico in 1988-1989, HTLV-I/II infection was found in 27 donors. HTLV-I/II infection was present in 1.0%-1.6% of American Indian and 0.16%-0.27% of Hispanic donors compared with 0.009%-0.06% of non-Hispanic white donors. HTLV-II was identified by DNA amplification in 12 of 13 samples from Indian and Hispanic seropositive donors. Despite apparent endemic HTLV-II infection in these populations, New Mexico Tumor Registry data showed that the incidences of hairy cell leukemia, mycosis fungoides, and chronic lymphocytic leukemia were comparable among the three ethnic groups. A population with endemic HTLV-II infection has been identified, and there is no evidence of increased risk for these three malignancies in the endemic groups.

Blood Donors

Human immunodeficiency virus and malaria in a representative sample of childbearing women in Kigali, Rwanda.

In 1986-1987 a consecutive sample of 3702 women presenting to prenatal and pediatric clinics at the only hospital in Kigali, Rwanda, was screened for human immunodeficiency virus (HIV) and malaria infection. The prevalence of HIV antibodies was 29%, and that of malaria parasites was 9%. HIV antibodies were more prevalent in women from the urban center than in those from the outskirts (31% vs. 20%, P less than .001), and malaria parasites showed the opposite prevalence pattern (8% vs. 15%, P less than .001); after stratifying by location, there was no association between HIV and the presence or degree of malaria parasitemia. HIV prevalence was 45% in women who had received a blood transfusion between 1980-1985 (before screening of donated blood began), and 28% among the great majority (94%) who had never been transfused. HIV prevalence was 44% in single mothers. 34% in women in common law unions, and 20% in those in legal marriages. These high rates of infection in the general population of Kigali highlight the need to develop effective programs for preventing further spread of sexually transmitted HIV.

Adult

Adjuvant therapy of stage II breast cancer treated with CMFVP, radiation therapy and VATH following lumpectomy. A pilot trial.

A pilot study was undertaken to assess the feasibility, toxicity, and efficacy of combined radiation therapy and chemotherapy in the adjuvant treatment of node-positive. Stage II patients with breast carcinoma who had undergone lumpectomy. Therapy consisted of three phases, starting with a six-week CMFVP (cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, prednisone) induction, followed by radiation therapy to the breast, and concluding with four cycles of VATH (vinblastine, Adriamycin, thiotepa, Halotesin). Twenty-seven patients were entered with an average age of 51.5 years (median 50 yrs) and a mean follow-up of 46.2 months. Twenty-three patients (85.2%) are alive and 19 (70.3%) disease free. There were no ipsilateral local recurrences. Cosmetic results were good to excellent in 26/27 patients. The doses of VATH were not compromised by the prior therapy. The regimen was found to be tolerable and is a reasonable approach in the adjuvant treatment of this particular patient population.

Adjuvants, Pharmaceutic

Comparing students' feedback about clinical instruction with their performances.

Validation of students' feedback as a measure of teaching effectiveness has been problematic for courses teaching clinical skills. This is true in part because establishing a valid and reliable method of assessing students' mastery of clinical skills has been a stumbling block. Reported here is the correlation of students' performances on an objective structured clinical examination (OSCE) with previously and independently collected feedback from students. In 1987-88, 190 second-year medical students at the University of Minnesota Medical School--Minneapolis spent one fourth of a second-year clinical skills course on neurology randomly assigned to one of four teaching sites--hospitals A, B, C, and D. Following their rotations, 180 of the students completed usable feedback forms. The students were consistently and significantly more positive about the teaching at hospital A. At the end of the year, all 190 students were tested using an OSCE having 20 stations, four of which presented neurologic problems. The students who had the neurology course at hospital A performed better on all four neurology problems, and differences were statistically significant for two of the problems. Feedback in this case accurately reflected a more effective teaching program.

Education, Medical, Undergraduate

Knowledge, attitudes, and perceived risk of AIDS among urban Rwandan women: relationship to HIV infection and behavior change.

We examined factors associated with perceived risk of AIDS, behavior change, and HIV infection in a representative sample of 1458 child-bearing urban women in Rwanda, central Africa. Although 68% of women reported only one lifetime partner, and the majority (87%) lived with a husband or steady partner, the prevalence of HIV antibodies was still high (32%). Before receiving their HIV test results, the women completed a questionnaire about AIDS knowledge, attitudes, and practices. Knowledge about HIV transmission was high, with 96-98% of women correctly identifying the three primary routes of infection. However, only 16% of women reported taking any action to avoid AIDS in the previous year, and most (11%) had done so merely by asking their male partners to change their behavior. Only 7% of women had ever tried condoms, and many (68%) thought they could be dangerous to use. Women who perceived themselves at risk of AIDS (57%) were more likely to report changing behavior; they were also more likely to be infected with HIV. Other factors associated with behavior change included having known someone with AIDS, having discussed AIDS with a male partner, and believing that condoms are not dangerous. Future interventions should enhance perception of risk, encourage male sexual partners to reduce risky behavior, and increase familiarity with condoms.

Adolescent

The Auckland skin clinic tinea pedis and erythrasma study.

Three hundred consecutive patients attending the Auckland Hospital dermatology clinic were examined clinically and microbiologically for evidence of interdigital or plantar mycological or bacterial infection. One hundred and nine patients were shown by laboratory investigation to have an infection. Of these, only 89 displayed clinical signs of infection. Erythrasma, a desquamative condition caused by Corynebacterium minutissimum, was the commonest infection in this study. The commonest dermatophyte isolated was Trichophyton mentagrophytes var interdigitale. There was a significant rise in the incidence of both types of infection with age.

Adolescent

Venous ulcers.

Explore the source record for details and available documents.

Clothing

Immunofluorescence localization of vinculin in ectoplasmic ("junctional") specializations of rat Sertoli cells.

We have investigated, using indirect immunofluorescence techniques, the possibility that vinculin is a component of Sertoli cell ectoplasmic specializations. Affinity-purified polyclonal antibodies produced against human platelet vinculin were used to probe fixed frozen sections of rat testis. Specific fluorescence occurs in Sertoli cell regions adjacent to spermatids and to basally situated junctional complexes, sites at which ectoplasmic specializations are known to occur. Staining also occurs in Sertoli cell regions associated with tubulobulbar complexes. The antibody also labels focal contacts in cultured human dermal fibroblasts, apical junctional sites of rat epididymal epithelium, and dense plaques of smooth muscle. Our results are consistent with the prediction that vinculin is likely a component of ectoplasmic specializations and are also consistent with the hypothesis that these structures are a form of actin-associated adhesion complex.

Animals

Pharmacokinetics, biodistribution and dosimetry of 99Tcm(V)DMSA in humans with squamous cell carcinoma.

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.

Aged

Subcellular biodistribution of 99Tcm(V) DMSA in squamous carcinoma: a comparative study in humans and in an animal tumour model.

Technetium-99m(99Tcm) (V) dimercaptosuccinic acid is a new imaging agent which has been used to evaluate head and neck squamous cell carcinoma (SCC). This study compared the subcellular biodistribution of 99Tcm(V)DMSA in an established rabbit tumour SCC model and in humans with head and neck SCC. In rabbits, approximately 17-37% of radioactivity was located on tumour cell membrane. Approximately 57-80% of radioactivity was located nonspecifically in tumour cytosol, only 2-6% was bound specifically to tumour mitochondria, and 1-4% bound specifically to microsomes. In humans, 25-45% of radioactivity was localized on tumour cell membrane and 28-60% localized nonspecifically in tumour cytosol. There was 11-20% of radioactivity specifically bound inside the cell to the mitochondria and 1-6% specifically bound to microsomes. These results show that although 99Tcm(V)DMSA is accumulated at sites of SCC, the localization process is nonspecific.

Aged

The reliability of palpation in the assessment of tumours.

There is now a joint UICC-AJC classification for cervical lymph nodes based mainly on the size of the nodes. There is a recognized error in palpation, not only for detecting the presence of tumour but also its size. This study used an animal tumour model system to compare the ability of 6 independent observers of varying experience to detect and stage superficially transplanted growths. A preclinical medical student was as good as a Consultant ENT Surgeon in predicting the presence of tumour but the ability to stage tumours accurately was related to experience. Whilst the most experienced observers accurately estimated the size of tumours less than 2 cm, they were less accurate for larger (greater than 2 cm) tumours which were constantly understaged. This phenomenon may have important clinical implications particularly related to current nodal staging criteria.

Animals

Technetium-99m (v) dimercaptosuccinic acid: a clinical and scintigraphic study in an animal tumour model.

Technetium-99m (99mTc) (v) dimercaptosuccinic acid (DMSA) is a new tumour-imaging agent which has been used to image head and neck squamous carcinoma. This study used an established rabbit tumour model to compare palpation versus planar scintigraphy in the detection of superficially transplanted cancers. Palpation detected 83% of tumours measuring less than 2 cm compared with 58% for scintigraphy. Overall, the sensitivity for palpation was 88% (77% specificity) compared with 50% (63% specificity) for scintigraphy.

Animals

Characterization, in vitro susceptibility, and clinical significance of CDC group HB-5 from Rwanda.

From June 1984 until July 1988, CDC group HB-5 isolates were recovered from the exudates of genital ulcers in 25 of 675 (3.6%) patients (204 women, 471 men) in Kigali, Rwanda. Among a group of 145 men presenting with urethritis but without genital ulcers, a positive culture for HB-5 of a specimen from the coronal groove of the penis of only 1 man (0.7%) was found. During the same period, the organism was not obtained in cultures of vaginal specimens from 838 women without genital ulcer disease. The main biochemical characteristics of the isolated microorganisms included weak oxidase positivity, catalase negativity, indole positivity, reduction of nitrate to nitrite, acid production from D-glucose and fructose, and H2S production. A total of 75% of the organisms were susceptible to penicillin G. beta-Lactamase production was detected by the chromogenic cephalosporin test in a quarter of the strains. This study confirms that HB-5 can be found in the genital tract. HB-5 was associated with genital ulcer disease in Rwanda. However, its etiologic role in patients with this condition remains unclear.

Drug Resistance, Microbial

Comparison of persistence of seven bovine viruses on bovine embryos following in vitro exposure.

The ability of seven cytopathic strains of bovine viruses to adhere to the zona pellucida of six-to-eight day-old bovine embryos were compared. Embryos were exposed to virus by placing them either in virus suspensions or by culturing them on infected bovine turbinate cultures for 18-24 h. After exposure to bovine virus diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBV), bluetongue virus (BTV), pseudorabies virus (PRV), vesicular stomatitis virus (VSV), parainfluenza 3 virus (PI3), or bovine enterovirus virus (BEV), the embryos were tested for virus by culture in bovine turbinate cells and by morphological examination using electron microscopy (EM). A special technique to minimize loss of embryos processed for EM was developed. More embryos had viral particles on the surface of the zona pellucida after exposure to 18-24 hour infected cell cultures than did embryos exposed to viral culture suspensions. The most dramatic finding was that BTV adhered in large numbers to the surface of the zona pellucida of exposed embryos. IBRV, PRV, and VSV comprised an intermediate group, with virions occasionally detected on the surface of exposed embryos after 5 washes. Therefore, extensive washing is required. The PI3 and BEV were easily removed from embryo-exposed virus by washing. BVD was difficult to identify morphologically, making assessment by EM unreliable. There was no evidence that any one of the seven viruses penetrated the intact zona pellucida. Using a micromanipulator, 42 embryos were also directly inoculated through the zona pellucida with +/- 50 picoliters of virus inoculum or medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Eosinophilia-myalgia syndrome associated with L-tryptophan ingestion. Analysis of four patients and implications for differential diagnosis and pathogenesis.

Four patients fulfilling the case definition for eosinophilia-myalgia syndrome are described, including one whose disease began in 1986. Each displayed a variety of symptoms: one suffered principally from myalgia and recovered spontaneously on discontinuation of L-tryptophan therapy; one exhibited progressive sclerodermiform skin changes, neuropathy, and myopathy; a third had prominent neuromuscular disease and sclerodermiform skin changes; and the fourth experienced profound weight loss, an axonal polyneuropathy, and perivascular lymphoid infiltrates simulating a lymphoma. Evidence of T-cell activation was present in peripheral blood and affected tissues during the clinically active progressive phase of disease. Among other manifestations pleural effusion, cutaneous vasculitis, joint contractures, and bloody diarrhea were observed. A history of L-tryptophan ingestion should be sought in patients with myalgia, fatigue, or the above outlined symptoms.

Adult