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Biomedical subjects

M Jennings

Publications and source records attributed to M Jennings.

At least 19 recordsLinked to original sources
PubMed1991

Audit of a new appointments system in a hospital outpatient clinic.

OBJECTIVE: To assess the effect of a new appointments system on patients' waiting time. DESIGN: Replacement of an existing system of regularly spaced appointments at 10 minute intervals with one in which the doctor arranged appointments according to his perception of individual patients' requirements, from December 1988 to June 1989. SETTING: One general medical outpatient clinic. PATIENTS: All (181) [corrected] patients under regular review with fixed appointment times during six months; those arriving for blood testing before the start of the clinic and those requiring ambulance transport were excluded. MAIN OUTCOME MEASURES: Mean waiting time (mean of difference between appointment time and start of consultation), maximum waiting time, number of patients, and total duration of clinics. RESULTS: Mean waiting time was reduced by about 30 minutes (from 39.6 to 9.5 mins) over the six months. There was no change in the number of patients attending (mean 15.8 v 15.4) or the duration of the clinics (mean 187 v 160 mins). CONCLUSION: Efficiency was improved by simple adjustment to the appointments system used in the hospital outpatient clinic.

Appointments and Schedules↗
PubMed1991

Cell-mediated infection of human placental trophoblast with HIV in vitro.

In order to investigate how human immunodeficiency virus (HIV) gains entry to the placenta, we have performed in vitro experiments in which highly purified trophoblast cells isolated from term human placentas were examined for their susceptibility to HIV infection. Trophoblast cells were exposed to cell-free HIV-1 for up to 24 h, after which the cultures were monitored by p24 antigen capture assay, reverse transcriptase assay, and electron microscopy for evidence of virus uptake and replication. None was found. In the second series of experiments, trophoblast cells were cocultured with HIV-infected MOLT-4 cells for 24 h, stained using an anti-HIV antibody, and examined by immunofluorescence microscopy. The MOLT cells were strongly positive, as expected, but many trophoblast colonies also showed a punctate staining pattern. Examination of similar cultures using the electron microscope revealed MOLT cells adherent to trophoblast but no evidence of cell-cell fusion. Virions were observed in coated pits at the trophoblast cell surface and in endosomes or multivesicular bodies in the cytoplasm. These observations are consistent with an endocytosis-mediated mechanism of virus entry. Virions were also observed budding from the trophoblast plasma membrane, indicating that these cells can support HIV replication. To our knowledge, these results show for the first time that HIV can infect placental trophoblast cells in vitro. The results suggest that the placenta could become infected with HIV by the interaction of virus-infected maternal lymphocytes with syncytiotrophoblast bordering the maternal blood in the intervillous space.

Female↗
PubMed1991

In vivo administration of tumor necrosis factor-alpha is associated with antiviral activity in human peripheral mononuclear cells.

Tumor necrosis factor-alpha (TNF-alpha) has a spectrum of biologic effects and has been shown to exert antiviral effects in fibroblasts in vitro. The in vivo administration of TNF-alpha (40-160 micrograms/m2 intravenously over 2 hr) and its effects on vesicular stomatitis virus (VSV) replication in peripheral blood mononuclear cells (PBMC) from patients with malignancy was investigated. Blood was obtained before, during, and after infusion. The PBMC were separated and infected with VSV at a multiplicity of infection of 0.005 plaque-forming units/cell and virus yields were determined 72 h later. The TNF-alpha inhibited VSV yields by as much as 99% in a dose-dependent manner with the inhibition initially observed during the first hour of infusion. Despite a rapid reduction in TNF-alpha serum levels, the higher doses still produced antiviral effects 4 hr after the infusion. Sera obtained at identical times had no interferon activity. Human gamma-interferon (25 micrograms/ml) added in vitro augmented the TNF-alpha-induced inhibitory activity in both magnitude and duration. Percentages of lymphocytes and monocytes in peripheral blood were reduced at 4 hr after TNF-alpha administration and the monocyte to lymphocyte ratio was diminished and temporally coincided with the loss of TNF-induced antiviral state. These data suggest that the in vivo administration of TNF has a direct inhibitory activity on VSV replication in human peripheral blood mononuclear cells that was enhanceable by gamma-interferon and possibly monocyte mediated.

Cells, Cultured↗
PubMed1991

SIV vaccine protection of rhesus monkeys.

Rhesus macaques (M. mulatta), immunized with an inactivated whole SIVmac vaccine and muramyl dipeptide or Freund's incomplete adjuvant, were protected against IV challenge infection with 10 animal infectious doses of the homologous virus. The protection in these animals appeared to be complete, with no breakthrough of latent virus infection over a 10-month period. Vaccine protection in this model was correlated generally with a high level of SIVmac envelope antibody by ELISA and immunoblot, high titers of syncytial inhibiting antibody, and, more specifically, with the presence of antibodies binding to a putative V3 loop synthetic peptide of the SIVmac outer envelope. This model can now be used for further identification of the protective epitopes and protective host immune responses as well as for development of novel and better AIDS vaccines.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

SIV, STLV-I and type D retrovirus antibodies in captive rhesus macaques and immunoblot reactivity to SIV p27 in human and rhesus monkey sera.

The prevalence of simian immunodeficiency virus (SIV), simian T-cell lymphotropic virus type 1 (STLV-I), and type D retrovirus (SRV-D) antibodies was determined for 1229 rhesus monkeys (Macaca mulatta) from two research colonies. Serum samples were tested by using enzyme-linked immunosorbent assay (ELISA), immunoblot (IB), and radioimmunoprecipitation assay (RIPA). Seropositive results for the three retroviruses tested were 0 for SIV, 270 (22%) for STLV-I, and 103 (8.4%) for type D retrovirus. Of the rhesus monkey sera, 61 (5.0%) were reactive to SIV gag p27 only, when tested by IB, but were negative when further tested by RIPA. Virus isolation was attempted from cultured peripheral blood mononuclear cells of 35 monkeys whose sera contained only p27 reactivity and none were positive by reverse transcriptase and core antigen assays to detect SIV. No overt clinical signs of immunodeficiency disease or unexplained deaths were evident in either monkey colony. Additionally, 63 of 165 (38%) human sera from various groups (primate center workers, normal donors, health care workers) had weak to moderate IB reactivity only to SIV p27, but 31 of 31 sera tested were negative by RIPA. These sera remained reactive to SIV p27 following absorption with an uninfected cell lysate, after blocking IB strips with various blocking solutions and were reactive to different SIV antigen preparations while remaining negative to human immunodeficiency virus type 1 (HIV-1) by IB and negative to HIV-2 by ELISA. These data underscore the need to adopt criteria for a positive SIV serologic test requiring reactivity against more than one viral gene product. These results also illustrate a potential problem in the testing of human sera for antibodies against simian retroviruses and demonstrate the need for caution in the interpretation of immunoblot results.

Animals↗
PubMed1990

Characterization of monoclonal antibodies that distinguish simian immunodeficiency virus isolates from each other and from human immunodeficiency virus types 1 and 2.

Two monoclonal antibodies (MAbs) against p27 and one against p17 of simian immunodeficiency virus (SIV) from rhesus macaques were produced and characterized by reacting with disrupted, viral antigens on immunoblots. Human immunodeficiency virus type 1 (HIV-1), HIV-2 and SIV isolates from sooty mangabey, stump-tailed macaque, rhesus macaque and African green monkey (SIVSM, SIVStM, SIVMAC and SIVAGM) were used for comparative analysis. The p27 monoclonal antibodies HE3 and FA2 reacted with SIVMAC and SIVSM, but not with HIV-1, HIV-2, SIVStM and SIVAGM. The p17 monoclonal antibodies reacted with SIVMAC and SIVStM, but not HIV-1, HIV-2, SIVSM and SIVAGM. The differential reactivity of these monoclonal antibodies indicated that common conserved antigenic epitopes are shared between SIVMAC and SIVSM with respect to p27 MAbs and between SIVMAC and SIVStM with respect to p17. Since these MAbs reacted differently with the SIV isolates, they are useful reagents for comparative pathogenesis studies for differentiating SIV isolates.

Animals↗
PubMed1990

Inactivated simian immunodeficiency virus vaccine failed to protect rhesus macaques from intravenous or genital mucosal infection but delayed disease in intravenously exposed animals.

Eight rhesus macaques were immunized four times over a period of 8 months with a psoralen-UV-light-inactivated whole simian immunodeficiency virus vaccine adjuvanted with threonyl muramyl dipeptide. Eight unvaccinated control animals received adjuvant alone. Only the vaccinated animals made antibodies before challenge exposure to the viral core and envelope as determined by Western blotting (immunoblotting) and virus-neutralizing antibodies. Ten days after the final immunization, one-half of the vaccinated and nonvaccinated monkeys were challenged exposed intravenously (i.v.) and one-half were challenge exposed via the genital mucosa with virulent simian immunodeficiency virus. All of the nonvaccinated control monkeys became persistently infected. In spite of preexisting neutralizing antibodies and an anamnestic antibody response, all of the immunized monkeys also became persistently infected. However, there was evidence that the clinical course in immunized i.v. infected animals was delayed. All four mock-vaccinated i.v. challenge-exposed animals died with disease from 3 to 9 months postchallenge. In contrast, only one of four vaccinated i.v. challenge-exposed monkeys had died by 11 months postchallenge.

Adjuvants, Immunologic↗
PubMed1990

Effect of virus dose and nonoxynol-9 on the genital transmission of SIV in rhesus macaques.

One inoculation of cell-free SIVmac (50 TCID50) caused persistent viremia in nine of 13 female rhesus macaques inoculated intravaginally. Persistent viremia was produced in two of four male rhesus macaques by twice placing cell-free SIVMAC (50 TCID50) onto the skin and urethral os of the penis. Placing a spermicide containing nonoxynol-9 into the vaginal canal prior to repeated intravaginal inoculations of SIV prevented transmission of the virus in three of six female rhesus macaques.

Administration, Intravaginal↗
PubMed1989

Culicoides: biological vectors of Akabane virus.

Akabane virus replicated in Culicoides nubeculosus and Culicoides variipennis after intrathoracic inoculation and was maintained in both species of midge for at least 9 days post-infection. The virus also replicated to high concentration in C. variipennis after oral infection and was transmitted through a membrane by this species of midge 7-10 days after infection. The experiments described in this paper provided the first definitive evidence that Culicoides spp. are able to act as fully competent vectors of Akabane virus.

Animals↗
PubMed1989

Genital mucosal transmission of simian immunodeficiency virus: animal model for heterosexual transmission of human immunodeficiency virus.

An animal model for the heterosexual transmission of human immunodeficiency virus (HIV) was developed by the application of simian immunodeficiency virus (SIV) onto the genital mucosas of both mature and immature, male and female rhesus macaques. Virus preparations were infused into the vaginal vaults or the urethras (males) of the animals through a soft plastic pediatric nasogastric feeding tube. The macaques that were infected by this route (six males and nine females) developed SIV-specific antibodies, and SIV was isolated from peripheral mononuclear cells of all seropositive animals. One male and one female infected by this route developed severe acquired immunodeficiency syndrome-like disease with retroviral giant-cell pneumonia. As few as two inoculations of cell-free SIV containing 50 50% tissue culture infective doses induced persistent viremia. Cell-free virus preparations were capable of producing infection by the genital route. Much higher doses of virus were required to transmit SIV by this route than are required for transmission by intravenous inoculation. Thus, it appears that the mucous membranes of the genital tract act as a barrier to SIV infection. Spermatozoa and seminal plasma were not required for the genital transmission of SIV. Rarely, SIV was recovered from mononuclear cells in semen and vaginal secretions. The SIV-rhesus macaque model is suitable for assessing the role of cofactors in heterosexual transmission of HIV and will be useful for testing the effectiveness of spermicides, pharmacologic agents, and vaccines in preventing the heterosexual transmission of HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Postexposure immunotherapy of simian immunodeficiency virus (SIV) infected rhesus with an SIV immunogen.

An inactivated whole simian immunodeficiency virus (SIV) immunogen given to healthy, seropositive rhesus macaques 4 months after infection had no effect on the humoral immune response to SIV, the presence of antigenemia, cell-associated viremia, or disease course. Further immunotherapeutic trials in this highly susceptible animal model should be carried out sooner after exposure, before significant loss of CD4 cells has occurred. The SIV infected macaque model will continue to serve an essential role in development and testing of anti-AIDS drugs and immunogens.

Animals↗
PubMed1988

Blue rubber bleb naevus disease: an uncommon cause of gastrointestinal tract bleeding.

A 23 year old woman presented with facial pain, a right parotid tumour and iron deficiency anaemia. She had several cutaneous venous swellings and tumours with a similar appearance were found in the large bowel. Histological examination of the parotid tumour and angiography of the skin and gut lesions confirmed that they were venous in origin. The aetiology, classification, and complications of disorders of the venous system and the importance of using a tourniquet to examine the peripheral veins is discussed.

Adult↗