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Biomedical subjects

S Reed

Publications and source records attributed to S Reed.

At least 73 records · Page 4Linked to original sources
PubMed1991

Detection of HIV-1 in Entamoeba histolytica without evidence of transmission to human cells.

Intestinal protozoa like Entamoeba histolytica and Giardia lamblia have been proposed as vectors or cofactors in the development of AIDS. To determine whether these protozoa could transmit HIV, laboratory strains of protozoa were cocultured with cells chronically infected by a highly replicative strain of HIV-1. Entamoeba histolytica, but not Giardia lamblia, took up virus. Immunologically detectable HIV-1 was present in the amebae up to 48 h after exposure to infected cells, but this virus could not be transferred to uninfected human cells. Amebae isolated directly from two HIV-infected individuals were also found to be positive for HIV-1. After lysis of these protozoa and coculture with uninfected peripheral blood mononuclear cells, no transfer of virus to the human cells was observed.

Animals↗
PubMed1991

Argon laser versus thermal cautery for punctal occlusion. An animal study.

A subset of the dry-eye patient group manifests their problem so severely that permanent punctal occlusion is required. The technique most often used today is thermal cautery. In this prospective study, an animal model was developed, and the effectiveness of the argon laser as a primary alternative therapy to thermal cautery was evaluated. Dogs were found to have a punctum similar in shape and location to humans; therefore, they were deemed to be a more appropriate animal model for punctal studies than cats. Both laser and thermal cautery are similarly effective in completely occluding puncta in animals. There was a trend toward greater stenosis with the laser in those puncta that were only partially occluded. In addition, laser punctal occlusion appeared to be less painful than thermal cautery.

Animals↗
PubMed1991

Isolation of a strain-specific Entamoeba histolytica cDNA clone.

Entamoeba histolytica is an intestinal parasite causing significant morbidity and mortality worldwide. More tools are needed to understand the epidemiology and molecular pathogenesis of amebiasis. A cDNA library was constructed by using poly(A)+ RNA isolated from an axenic strain of E. histolytica, HM1:IMSS, which expresses a pathogenic isoenzyme pattern (zymodeme). Differential screening of the library yielded a strain-specific 3' polyadenylated cDNA clone, C2, possessing nine 26-nucleotide tandem repeats. RNA and DNA transfer blot analysis of four axenic strains of E. histolytica possessing the same pathogenic zymodeme revealed that the gene is present and expressed in pathogenic E. histolytica HM1:IMSS and 200:NIH but is not present in pathogenic strains HK-9 and Rahman. In addition, Southern blot analysis using the C2 clone showed heterogeneity of genomic organization between HM1:IMSS and 200:NIH. DNA dot blot hybridization analysis demonstrated that cDNA clone C2 was also able to distinguish axenically cultured E. histolytica strains possessing pathogenic zymodemes from those possessing nonpathogenic zymodemes and could detect as few as 100 amebic trophozoites. We conclude that C2 is a strain-specific E. histolytica cDNA clone that, in conjunction with other E. histolytica-specific probes, could serve as a useful epidemiologic tool.

Animals↗
PubMed1990

Computerization of plateletpheresis quality control records with a commercially available spreadsheet program.

Many apheresis units lack the resources to acquire customized computer software for record keeping. We have adapted a commercially available "spreadsheet" program (Lotus 1-2-3) to aid in quality control activities for plateletpheresis. Data are entered in a grid pattern wherein each donation occupies one row and successive columns contain numerical data derived from the donation. The last two columns contain formulas that calculate yield and collection efficiency from values entered in preceding columns. The program runs on an IBM PC or equivalent with 512 K RAM; the combined cost of a computer and software is currently under $2,000.00. Data entry requires fewer keystrokes per record than computation of yield and efficiency with a calculator, and creates an inclusive permanent record for future analysis. Data sorting and statistical functions allow rapid identification of incomplete records, and derivation of average platelet yield and/or collection efficiency for any time period of interest. The program also facilitates determining the proportion of donations that fall below any chosen cutoff. Performance characteristics of a particular instrument or operator can be assessed easily by isolating the pertinent records and analyzing them separately. The system will thus accomplish a variety of quality control activities, including those mandated by licensing agencies. It can be implemented by apheresis personnel with limited "computer literacy" and is superior to manual tabulation of quality control data in both ease of data entry and facility of analysis.

Data Interpretation, Statistical↗
PubMed1990

Adapting problem-based learning to a traditional curriculum: teaching about prevention.

How best to teach medical students is an issue of importance in medical education. At Dartmouth Medical School, a required first-year course emphasizes small-group learning through five modules that are both problem-based and task-oriented. The prevention module that requires small groups to plan the solution to a problem in prevention is described. Evaluation reveals that the program is feasible for teaching about prevention, and that the following principles are important to consider when implementing problem-based, task-oriented learning in an otherwise traditional curriculum: (1) Be clear in explaining the unique expectations and requirements of small-group learning to students. (2) Limit the duration of any special learning module to less than a week. (3) Take into account the demands of the traditional curriculum when scheduling to minimize competition with traditional examinations.

Curriculum↗
PubMed1989

DNA hybridization probe for clinical diagnosis of Entamoeba histolytica.

As an alternative to microscopic identification of Entamoeba histolytica parasites isolated from stool, a sensitive and species-specific DNA hybridization probe was made for rapid diagnosis of E. histolytica parasites in clinical samples directly applied to nylon membranes. The DNA hybridization probe was made by screening a genomic library of a virulent HM-1:IMSS strain of E. histolytica to detect recombinant plasmids containing highly repeated parasite DNA sequences. Four plasmid clones that reacted across Entamoeba species coded for highly repeated rRNA genes of E. histolytica. Four other plasmid clones were E. histolytica specific in that they bound to four axenized and nine xenic strains of E. histolytica but did not recognize closely related E. histolytica-like Laredo, Entamoeba moshkovskii, or Entamoeba invadens parasites. The diagnostic clones detected as few as eight cultured amoebae and did not distinguish between pathogenic and nonpathogenic zymodemes of E. histolytica. The diagnostic clones were sequenced and contained 145-base-pair sequences which appear to be tandemly repeated in the genome. No stable transcript which is homologous to the diagnostic DNA was detected. In a study of stool samples from Mexico City shown by microscopy to contain E. histolytica, Entamoeba coli, Giardia lamblia, Endolimax nana, Trichuris trichiuria, and Chilomastix mesnili parasites, the DNA hybridization probe demonstrated a sensitivity of 1.0 and a specificity of 0.93. We conclude that the DNA hybridization probe can be used for rapid and accurate diagnosis of E. histolytica parasites.

Animals↗
PubMed1989

Restoration of wrist extension after paralysis.

Loss of active extension of the wrist is a major functional handicap for the affected patient. Restoration of wrist extension, primarily accomplished via tendon transfers, is a fundamental part of surgical treatment after paralysis. The anatomy and physiology of the wrist, the clinical aspects, the history, and restorative treatment of wrist extension after paralysis are discussed.

Humans↗
PubMed1988

Aberrant protamine 1/protamine 2 ratios in sperm of infertile human males.

Protamines were extracted from the sperm of fertile and infertile human males and the relative proportion of protamines 1, 2, and 3 were determined by scanning microdensitometry following electrophoresis of total protamine in polyacrylamide gels. The proportion of the three protamines was found to be similar in sperm obtained from different normal males. The distribution of protamines in sperm obtained from a select group of infertile males producing an elevated level of large sperm heads, in contrast, was different from that of the fertile males.

Densitometry↗
PubMed1988

Visceral leishmaniasis: a disease associated with inability of lymphocytes to activate macrophages to kill leishmania.

1. The production of lymphokines capable of activating macrophages to kill leishmania was evaluated in seven visceral leishmaniasis patients. 2. Macrophages from healthy donors cultivated in vitro with supernatants from lymphocyte cultures of visceral leishmaniasis patients were infected with L. d. chagasi or L. m. amazonensis. After infection the number of amastigotes per 100 cells was counted. 3. The supernatant from visceral leishmaniasis lymphocytes did not significantly reduce the number of intracellular amastigotes of L. donovani chagasi (89 +/- 27%) in relation to controls (culture containing medium alone). In contrast, supernatants of mucocutaneous lymphocyte cultures decreased the percentage of infection to 26 +/- 11%. The supernatant of antigen-stimulated lymphocyte cultures from visceral leishmaniasis patients also did not inhibit L. mexicana amazonensis growth. The supernatant of visceral leishmaniasis lymphocytes stimulated with PHA reduced the number of intracellular amastigotes to 62 +/- 23% in relation to controls. 4. The inability of lymphocytes from visceral leishmaniasis patients to proliferate when stimulated with leishmania antigens and to activate macrophages to kill leishmania may represent a fundamental defect and lead to the acquisition of the disease.

Adolescent↗
PubMed1986

A case of fatal sodium azide ingestion.

A fatal case of sodium azide poisoning in which exchange blood transfusions, charcoal hemoperfusion, hemodialysis and potent vasopressor agents failed to prevent the development of circulatory collapse associated with a wide complex cardiac rhythm is presented. The cellular toxin sodium azide resulted in the development of an altered mental status, profound metabolic acidosis, cardiac arrhythmia (atrial fibrillation and terminal wide complex arrhythmias), a relative decrease in cardiac output, hypotension and non-cardiogenic pulmonary edema. Further animal studies are needed to gain new approaches for the treatment of this rare cause of human poisoning.

Acidosis↗
PubMed1985

Assessment and management of asthma in an accident and emergency department.

Patients with asthma presenting to the accident and emergency department at Southampton General Hospital during 12 months were reviewed retrospectively to determine how many patients attended, when and how patients were assessed and treated, and what factors appeared to influence whether a patient was admitted to a medical ward or not. Thirty five visits were made by patients requesting a repeat prescription for a metered dose inhaler. A further 193 visits were made by 152 patients (93 male, 59 female); only data on the first visit of any individual were analysed in this study. Patients were more likely to visit in the autumn, at the weekend, and in the evenings. Observations and measurements used to assess the severity of asthma were recorded with variable frequency--heart rate in 84% of examinations, pulsus paradoxus in 13%, and peak flow rate in 11%. Blood pressure was five times more likely to be recorded than peak flow rate. The drugs used to treat asthma were, in order of frequency, a beta agonist (120 patients), intravenous aminophylline (39), and intravenous corticosteroids (30). Sixty (39%) of the patients were admitted to a medical ward. Admission was more likely to occur when patients arrived during the week than at the weekend, when they had cyanosis or pulsus paradoxus, and after receiving parenteral treatment. There was no difference in mean heart rate between patients admitted to the ward and those discharged home. Although there was no specific evidence of inappropriate admission to or discharge from hospital in this retrospective study, the failure to record more objective measurements of the severity of asthma and, in particular, the extent of the airflow obstruction, is cause for concern.

Adolescent↗
PubMed1985

Cell mediated immunity in American cutaneous and mucosal leishmaniasis.

Cellular immune responses were studied in 35 Brazilian patients with either active cutaneous leishmaniasis (CL), active mucosal leishmaniasis (ML), or healed cutaneous leishmaniasis. The mean age and duration of illness in the two groups were as follows: 14 CL patients, age 28 +/- 13 yr, disease 5 +/- mo; and 16 ML patients, age 34 +/- 15 yr, disease 86 +/- 117 mo. Patients with CL and ML responded well to leishmania antigen in blastogenesis assays. However, the response of ML patients was over three times greater than the response of CL patients. There was a significant correlation between the magnitude of the lymphoproliferative response and the duration of disease activity. There were no significant differences between CL and ML patients in terms of the following parameters: lymphoproliferative responsiveness to mitogens (phytohemagglutinin, concanavalin A, and pokeweed mitogen) and peripheral blood lymphocyte subpopulations (T and B cells, oKT8+ and OKT4+ cells, OKT4:OKT8 ratio). Peripheral blood mononuclear cells from ML patients also generated interferon-gamma containing lymphokine in response to stimulation with leishmania antigen. This lymphokine was capable of inducing macrophages from ML patients to inhibit the intracellular multiplication of leishmania in vitro. These studies have determined that the parameters of lymphocyte and macrophage functions evaluated in ML and CL patients are comparable, except for an enhanced lymphoproliferative response, with leishmania antigen in ML patients. This later finding may be a function of the long duration of active disease in this population and unrelated to the pathogenesis of their mucosal lesions.

Adolescent↗