Search PubMed⌕ Search

Biomedical subjects

M Dawson

Publications and source records attributed to M Dawson.

At least 145 records · Page 8Linked to original sources
PubMed1983

Cyst and host tissue concentrations of mebendazole in patients undergoing surgery for hydatid disease.

Mebendazole levels were assayed by high performance liquid chromatographic assay in plasma, host tissues, and hydatid material taken from four patients who underwent surgery for hydatid disease. The drug was absorbed and had penetrated both into the host and into the parasite material. The levels of the drug in viable hydatid cysts were much lower than those in dead cysts. The possibility of exclusion or detoxification of the drug by viable hydatid cysts is raised.

Benzimidazoles↗
PubMed1983

Isolation of a syncytium-forming virus from a goat with polyarthritis.

Virus particles, morphologically indistinguishable from maedi-visna virus or caprine arthritis-encephalitis virus, were detected in tissue explant cultures prepared post mortem from a goat with joint, lung and kidney lesions similar to those associated with the caprine arthritis-encephalitis complex. Serum from this goat and others in its herd of origin gave positive reactions in an agar gel immunodiffusion test for maedi-visna virus antibodies.

Animals↗
PubMed1983

Investigations of a flock heavily infected with maedi-visna virus.

Following the discovery that a flock of sheep in England was infected with the virus of maedi-virus, several seropositive sheep were brought to the Central Veterinary Laboratory and kept isolated and under observation for up to three years before being further examined at necropsy. Meanwhile, sheep in the infected flock which died or were culled were examined after death for evidence of the actual disease. At necropsy pulmonary disease was a common (although not always the sole) finding, the lesions being mostly chronic pasteurellosis and pulmonary adenomatosis. One of the 45 carcases examined showed classical lesions of advanced maedi. In four others, early or incipient lesions of maedi were found in otherwise normal lungs, while in three more, maedi was coincidental with the other pulmonary diseases. No clinical evidence to suggest maedi, other than emaciation, was seen in any of the sheep with lesions of the disease.

Animals↗
PubMed1983

The effects of cisplatin on normal human erythrocytes in vitro.

Therapeutic administration of cisplatin is often followed by anaemia which may not be due entirely or even largely to myelosuppression but rather to drug-induced haemolysis. Similar experience with other cytotoxic agents prompted earlier investigations which yielded evidence of drug-induced changes in RBC shape in vitro. Current studies of cisplatin and bleomycin, which have been used together in clinical practice, revealed a significant alteration in the profile of RBC morphology; specifically a reduction in the number of 'bowl' shaped cells. However, this finding is in contrast to the increase in 'bowls' which was observed previously with other drugs. So it appears that direct erythrocytotoxicity cannot explain the occurrence of anaemia in patients who receive cisplatin. An alternative mechanism, similar to that of penicillin induced haemolysis, is suggested by immunoradiometric assays of surface IgG on red cells.

Bleomycin↗
PubMed1982

Comparison of serological tests used in three state veterinary laboratories to identify maedi-visna virus infection.

Three immunoassays used in Dutch, Belgian and British state veterinary laboratories for the detection of antibodies to maedi-visna virus were compared. These were an indirect enzyme-linked immunosorbent assay (ELISA), an indirect immunofluorescence test (IIFT) and an agar gel immunodiffusion test (AGIDT). The results indicated that all three assays were of similar sensitivity and specificity with identical results being recorded for 91 of 100 samples. The results of the ELISA and the AGIDT produced the closest correlation with agreement in 97 of 100 samples. With the IIFT and the AGIDT there was agreement in 94 of 100 samples and with the ELISA and the IIFT in 91 of 100 samples.

Animals↗
PubMed1982

Detection of herpes simplex virus mRNA in latently infected trigeminal ganglion neurons by in situ hybridization.

Latent infection of the trigeminal ganglion with herpes simplex virus type 2 (HSV-2) was studied in guinea pigs by in situ DNA hybridization. Frozen ganglion sections from animals killed during the period of latent virus infection were studied under nondenaturing conditions. Some sections were treated with deoxyribonuclease (DNase) or ribonuclease (RNase) before incubation with HSV DNA probes. HSV probes consisted of viral DNA nick translated and labeled in vitro with tritiated nucleotides. Bacteriophage lambda DNA, similarly prepared, was used as a control probe. The lambda probe was negative in all situations, including HSV-2-infected monolayer cells in cell culture. HSV-2 probes produced heavy label and, therefore, evidence of hybridization with HSV-2-infected monolayer cells. When HSV-2 probes were incubated with latently infected ganglion sections, hybridization was detected in 71% of guinea pigs and 46% of ganglia. Label was seen only in neurons, and in positive ganglia 0.3 to 5% of neurons were labeled. The amount of label was markedly decreased by pretreatment of ganglion sections with RNase but not DNase, indicating that the DNA probes hybridized to HSV messenger RNA in the latently infected ganglia.

Acute Disease↗
PubMed1982

The pharmacokinetics and bioavailability of mebendazole in man: a pilot study using [3H]-mebendazole.

Following the intravenous administration of a tracer dose (1.7 microgram) of [3H]-mebendazole to a man, an elimination half-life of 1.16 h was observed and the volume of distribution was calculated to be 2.03 l/kg. After oral administration of the same dose, an elimination half-life of 0.74 h was observed. The bioavailability of mebendazole from the solution was found to be 17%.

Benzimidazoles↗
PubMed1982

The influence of an experimental immune synovitis on the failure mode and strength of the rabbit anterior cruciate ligament.

The strength and failure mode of a fresh femur-anterior cruciate ligament-tibia complex was studied in normal rabbits and after the induction of an experimental immune synovitis. Five modes of failure were observed: (1) through the anterior cruciate ligament alone; (2) through a small piece of bone with the anterior cruciate ligament attached; (3) through a condyle; (4) through the metaphysis; and (5) through the diaphysis. In the normal complex, failure always occurred through the anterior cruciate ligament. In the controls, the average ratio of failure-load to body weight was seventy-four newtons per kilogram. After induction of an immune synovitis this ratio was significantly reduced, to twenty-two newtons per kilogram. Synovial cathepsin-D enzyme activity in these knees was 5.27 micromoles per hour per milligram of protein, which was significantly elevated when compared with the control level of 0.26. Histological examination of the anterior cruciate ligament after induction of the immune synovitis but before strength-testing demonstrated loss of the normal undulating fiber orientation, disorganization of the normal cellular pattern, and a decrease in the staining of the interstitial matrix with Mallory trichrome. There was a moderate infiltration of mononuclear and polymorphonuclear inflammatory cells in the body of the ligament. Histological studies of the ligament after strength-testing showed that the failure resulted in a mop-like appearance and morphological characteristics similar to those observed before testing.

Animals↗
PubMed1981

Translational regulation: identification of the site on bacteriophage T4 rIIB mRNA recognized by the regA gene function.

The bacteriophage T4 gene regA encodes a protein that diminishes the expression of many unlinked early T4 genes. Previous work demonstrated that regA-mediated repression occurs after transcription. We report here on the identification of the target site on one regA-sensitive mRNA, the message encoding the phage T4 rIIB protein. The target for regA-mediated action overlaps the translational initiation domain of the rIIB messenger. The regA protein may be a repressor that operates translationally on a significant and interesting set of early phage T4 mRNAs.

Base Sequence↗
PubMed1981

Experimental Escherichia coli and rotavirus infection in lambs.

Colostrum-deprived lambs were infected with either enteropathogenic Escherichia coli(O9:K30:K99) or rotavirus or a mixture of the E coli and rotavirus. E coli doses of 10(6) and above consistently produced diarrhoea, as did experimental rotavirus infection. When both of the agents were administered, the mortality rate was higher, although the duration of diarrhoea was no greater than that observed when either of the two agents was administered alone.

Animals↗
PubMed1981

Once daily dosage versus divided daily doses of carbamazepine therapy in epileptic patients: a pilot study.

The effect of once daily dosage of carbamazepine on fit frequency, electroencephalogram (EEG), behaviour and 24-hour drug levels were compared with those following 2 to 3 divided daily doses treatment. The 14 male epileptics, aged 16 to 18 years, who were studied had already been receiving carbamazepine for an average period of 2.5 years in combination with other anti-epileptic drugs. In this investigation, these patients received their usual daily dose (mean dose 13.9 mg/dg) of carbamazepine in 3-time, twice and once daily regimens. Each treatment period lasted for 4 weeks. Plasma concentrations of carbamazepine and its epoxide metabolite remained within the therapeutic range during the three treatment periods, but the area under the curves were greater during once daily medication. There was also slight decrease in the plasma sodium valproate concentration during the once daily regimen, but the concentrations of other concomitant medication remained unchanged. No significant changes in fit frequency and behaviour were observed athe area under the curves were greater during once daily medication. There was also slight decrease in the plasma sodium valproate concentration during the once daily regimen, but the concentrations of other concomitant medication remained unchanged. No significant changes in fit frequency and behaviour were observed athe area under the curves were greater during once daily medication. There was also slight decrease in the plasma sodium valproate concentration during the once daily regimen, but the concentrations of other concomitant medication remained unchanged. No significant changes in fit frequency and behaviour were observed and none of these patients suffered from any side-effects or toxic effects during once daily medication. EEG revealed a slight increase in abnormality during twice daily medication, but no further deterioration was seen during one daily treatment. In view of this observation, carbamazepine is probably effective as a single daily dose, but further long-term controlled clinical trial in necessary.

Adolescent↗
PubMed1980

Maedi/visna: a review.

A brief history of the occurrence of maedi/visna or maedi/visna related diseases is given. The clinical features and diagnosis are described. Recent experimental work performed in an attempt to resolve the pathogenetic features of slowness and persistence of infection, characteristic of maedi/visna, is covered. A description of the epidemiology is given followed by possible methods of control.

Animals↗
PubMed1979

The demonstration of maedi/visna virus in sheep in Great Britain.

A virus indistinguishable from that causing maedi/visna has been isolated from a sheep flock in Great Britain. The virus was identified in cell cultures using immunofluorescent and electron microscopical techniques. The complement fixation test and the agar gel immunodiffusion test were used to assess the proportion of serological reactors within the flock. There has been no evidence of clinical disease in the flock into which foreign imports were introduced in the years prior to 1976.

Animals↗