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Biomedical subjects

M Jennings

Publications and source records attributed to M Jennings.

At least 73 records · Page 4Linked to original sources
PubMed1984

Cerebro-ocular dysgenesis (Walker-Warburg syndrome): neuropathologic and etiologic analysis.

We studied three cases (two of them siblings) with ocular and cerebral dysgenesis (Walker-Warburg syndrome). The histologic changes suggest that the disorder results from a sclerosing meningoencephalitis active through the second and third trimesters, but different from that typically encountered with known congenital pathogens. This illness was encountered first in the 1930s and has been reported with increasing frequency since 1970. The risk of recurrence among siblings exceeds 50%, with a predilection for involving consecutive siblings, a high incidence of reproductive failure, and no transmission across generations. The evidence suggests that an acquired agent may be transmitted transplacentally through consecutive pregnancies.

Abnormalities, Multiple↗
PubMed1984

The effect of paraffin wax embedding procedures on the ability of the fluorescent antibody test to demonstrate bluetongue virus antigen in insect tissue.

The effect of the reagents used in paraffin wax embedding procedures on the fluorescent antibody technique was investigated with a view to using this test for virus location studies on paraffin wax sections of bluetongue virus infected Culicoides variipennis. Experiments were carried out using tissue smears rather than prepared sections, enabling the effect of individual reagents to be evaluated. Infected smears treated with acetone alone showed bright specific fluorescence, while treatment of infected smears with all other reagents, including low melting point wax and acetone-soluble ester wax, prior to immunofluorescence testing reduced the brightness of specific fluorescence or rendered the test completely ineffective.

Animals↗
PubMed1983

Laboratory infection of the sandfly Phlebotomus papatasi Scopoli (Diptera, Psychodidae) with three Phleboviruses.

Membrane feeding and intrathoracic inoculation techniques were used to infect Phlebotomus papatasi sandflies with Phlebotomus fever group viruses. Sandflies were orally infected with Pacui virus, and were inoculated with Pacui, Sicilian sandfly fever and Naples sandfly fever viruses. Pacui virus did not multiply in these insects after oral infection, but an 8 X 10(4)-fold increase in virus concentration occurred within four days of intrathoracic inoculation of this virus. The infection rate was 100%. Sicilian sandfly fever virus multiplied in P. papatasi after infection by inoculation, although the yield was lower, a 20-fold increase in the mean virus concentration occurring over eight days. The results for Naples sandfly fever were inconsistent. A 32-fold increase in mean virus concentration was recorded in a small percentage of insects 14 days after inoculation of the virus.

Animals↗
PubMed1982

The susceptibility of Culicoides variipennis Coq. (Diptera: Ceratopogonidae) to laboratory infection with Rift Valley fever virus.

The vector potential of Culicoides variipennis for Rift Valley fever virus (RVFV) was investigated. Insects from a colony maintained at the Animal Virus Research Institute, Pirbright, were fed through a membrane on a mixture of mouse blood and RVFV (virus concentration of blood meal 7 X 95 log10 MLD50ml). Engorged insects were maintained at 25 degrees C +/- 1 degrees C. Samples of insects were tested at daily intervals to determine their virus content. Four of the five females tested immediately after feeding contained virus. The mean virus concentration of these infected flies was 2 X 7 log10MLD50. The virus concentration per fly decreased to 0 by day 2 post infection. On day 3, a virus concentration of 2 X 4 log10 MLD50 per fly was recorded from a pool of 17 flies but between day 4 and day 12 when the experiment terminated no virus was detected in any of the 135 females tested. Because of the pathogenic nature of RVFV, this work was carried out under the stringent security regulations at the PHLS Centre for Applied Microbiology and Research, Porton Down. The problems arising from experiments requiring the handling and infection of insects under such conditions are described.

Animals↗
PubMed1980

Significance of phenotypic and chromosomal abnormalities in X-linked mental retardation (Martin-Bell or Renpenning syndrome).

With the exception of macro-orchidism, three families with X-linked mental retardation showed diagnostic concordance of clinical features among the affected males. Since macro-orchidism was a variable feature among the otherwise identically affected males in one family, we question the existence of a separate entity of X-linked mental retardation characterized only be testicular enlargement. The X chromosome marker of Lubs was expressed, under the culture conditions of Sutherland, in lymphocytes of the affected males of two families, one with and the other without megalotestes. Two affected members of the third family, with megalotestes, did not show the marker. Telomeric structural changes similar to the mar(X) (qter) formation were found on certain autosomes, notably, chromosome 6 in some of the affected males, potential and obligate carrier females, and in both related and unrelated normal males. These autosomal markers appear to represent a nonspecific response to either in vivo or in vitro folate deficiency. Caution against premature introduction of this test for prenatal diagnosis, in the face of current ignorance regarding diagnostic specificity, is urged.

Female↗
PubMed1980

Replication of eubenangee virus in Culicoides nuberculosus (Mg.) and Culicoides variipennis (Coq.).

Eubenangee virus multiplied to a high titre in both Culicoides variipennis and C. nuberculosus after intrathoracic inoculation but only in C. varriipennis after oral ingestion. 7.9 per cent of the orally infected C. variipennis supported virus replication and transmission of virus was demonstrated after 15 days' incubation at 26 degrees C. The significance of low infection rates when assessing vector potential in the laboratory and the relevance of these infection rates to the field situation are also discussed.

Animals↗
PubMed1980

The susceptibility of the sandfly Lutzomyia longipalpis (Lutz & Neiva), diptera, phlebotomidae, to laboratory infection with bluetongue virus.

Bluetongue virus multiplied in the sandfly Lutzomyia longipalpis after intrathoracic inoculation but not after oral ingestion of virus. The level of virus multiplication was lower than that observed in similar experiments with the North American vector of bluetongue, Culicoides variipennis. Inoculated sandflies did not transmit virus after 6 to 9 days incubation at 25 degrees C. It is unlikely that L. longipalpis would be important in the maintenance of bluetongue virus in the wild.

Animals↗
PubMed1980

Influence of pH on the response of cells to single and split doses of hyperthermia.

The time course of development and loss of thermotolerance in Chinese hamster ovary cells exposed to 42 degrees was determined. The influence of pH on the heat sensitivity of normal and thermotolerant cells was examined. Exposure of cells to single graded heat treatments at pH 7.4 resulted in a decrease in survival to 5 to 10% after 3 to 4 hr treatment. Continued heating for an additional 4 to 5 hr resulted in an additional decrease in survival by a factor of only 1 to 2. At pH 6.7, exposure of cells to single heat treatments caused a marked reduction in survival to congruent to 0.02% after 3 hr treatment, and resistance to further killing was not evident until survival decreased to congruent to 0.001%. Cells initially heated at pH 7.4 for 3 hr and then stored at 37 degrees remained resistant to additional treatment for up to 48 hr later. Thermotolerance began to decay 72 hr after the initial treatment and was lost when 144 hr separated the treatments. The marked resistance to second treatments was observed irrespective of the pH at the time of the second treatment. Parallel studies also established that the viable progeny of heated cells remained resistant to hyperthermia for more than one postheat generation. These studies suggest that low pH conditions occurring in tumors may be expected to maximally influence response when fractionation intervals are sufficiently long that thermotolerance decays between treatments.

Animals↗
PubMed1979

The susceptibility of cell lines of Aedes aegypti (Linn.), Aedes albopictus (Skuse) and Aedes pseudoscutellaris (Therobald) to infection with blutongue virus.

Bluetongue virus multiplied in cell lines derived from Aedes albopictus and Aedes pseudoscutellaris cells. Virus reached a maximum titre in the Ae. pseudoscutellaris cells three days post inoculation, and in Ae. albopictus cells six days p.i. Virus growth was demonstrated in both cell lines at 27 degrees C and 37 degrees C. Significant titres of virus were still present in the Ae. albopictus cells after five subcultures at 27 degrees C over a period of six weeks. No cytopathic effect was observed in either cell line. A third cell line derived from the mosquito Ae. aegypti did not support the growth of Bluetongue virus.

Aedes↗