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Biomedical subjects

R M Williams

Publications and source records attributed to R M Williams.

At least 181 records · Page 10Linked to original sources
PubMed1979

Spontaneous diabetes mellitus: reversal and prevention in the BB/W rat with antiserum to rat lymphocytes.

Injections of rabbit antiserum to rat lymphocytes reversed hyperglycemia in 36 percent of spontaneously diabetic rats (Bio Breeding/Worcester) and prevented diabetes in susceptible nondiabetic controls. These findings strengthen the hypothesis that cell-mediated autoimmunity plays a role in the pathogenesis of diabetes in this animal model that mimics many morpholigic and physiologic characteristics of human insulin-dependent diabetes mellitus.

Animals↗
PubMed1979

Prevention and treatment of endometrial disease in climacteric women receiving oestrogen therapy.

The treatment regimens are described in 74 patients with endometrial disease among 850 climacteric women receiving oestrogen therapy. Cystic hyperplasia was associated with unopposed oestrogen therapy without progestagen. Two courses of 21 days of 5 mg norethisterone daily caused reversion to normal in all 57 cases of cystic hyperplasia and 6 of the 8 cases of atypical hyperplasia. 4 cases of endometrial carcinoma referred from elsewhere demonstrated the problems of inappropriate and unsupervised unopposed oestrogen therapy and the difficulty in distinguishing severe hyperplasia from malignancy. Cyclical low-dose oestrogen therapy with 7--13 days of progestagen does not seem to increase the risk of endometrial hyperplasia or carcinoma.

Adenocarcinoma↗
PubMed1979

Influence of genetic factors on natural resistance of mice to Pseudomonas aeruginosa.

In order to determine whether genetic background influences natural resistance to Pseudomonas aeruginosa, a series of 16 different strains of inbred mice were challenged intraperitoneally with P. aeruginosa. Significantly greater natural resistance to infection was found in mice of C3H background genome than in mice of A background genome. This phenomenon was documented for two different strains of P. aeruginosa but could not be demonstrated in control studies in which mice were intraperitoneally challenged with Staphylococcus aureus or Escherichia coli. The enhanced resistance of C3H mice was independent of currently defined haplotypes at the H-2 locus. The killing activity of serum against Pseudomonas was not greater in C3H mice than in A mice. The extension of these findings to disease in humans suggests that the particular susceptibility of certain populations of patients to Pseudomonas may be partially related to genetic factors.

Animals↗
PubMed1979

A light and electron microscopic study of an ovarian and rectal carcinoid.

An ovarian and rectal carcinoid within the same person is described. The ovarian carcinoid is non-argentaffinic with typical regular granules. The rectal tumour consists of two types of APUD cells, some argentaffinic and diazo-positive, whilst others are non-argyrophilic. These features are mirrored ultrastructurally, some cells containing the large pleomorphic argentaffinic granules while others have smaller regular granules. In addition, focal aggregates of microfilaments were found in both tumour types. These findings are discussed in terms of the APUD concept. The similarities of the APUD tumour cells to D1 APUD cells of the duodenum is highlighted, and an alternative explanation for their derivation is proposed.

APUD Cells↗
PubMed1979

An ultrastructural study of a nasal haemangioendothelioma.

A malignant haemangioendothelioma of the nose has been examined with the electron microscope. The tumour is predominantly poorly differentiated with only little evidence of its vascular ancestry identified. The cells are polygonal with a wide spectrum of organelles, including microfilaments. A conspicuous feature was the presence of cytoplasmic fenestrae developing into intracytoplasmic vacuolated spaces. The satisfactory progress of this patient is noted, and the value of electron microscopy in enabling an early and accurate diagnosis of this tumour to be made is emphasised.

Adult↗
PubMed1979

Spontaneous diabetes in the gnotobiotic BB/W rat.

To determine the influence of infectious agents on the initiation of diabetes in the spontaneously diabetic Bio-Breeding/Worcester (BB/W) rat, susceptible rats were raised in a germ-free environment. Between 2 and 3 mo of age, 3 of 12 pups became diabetic. Histologic examination of the pancreas revealed insulitis or end-stage islets. Culture and smears from various tissues were negative for bacteria or parasites. Serum vital antibody titers for all known rat viruses were undetectable. These data suggest that the diabetic syndrome of the BB/W rat is not dependent on recognized infectious agents.

Animals↗
PubMed1978

The evolution of sexual reproduction as a repair mechanism. Part II. Mathematical treatment of the wheel model and its significance for real systems.

The dynamics of populations of self-replicating, hierarchically structured individuals, exposed to accidents which destroy their sub-units, is analyzed mathematically, specifically with regard to the roles of redundancy and sexual repair. The following points emerge from this analysis: 1. A population of individuals with redundant sub-structure has no intrinsic steady-state point; it tends to either zero or infinity depending on a critical accident rate alpha c. 2. Increased redundancy renders populations less accident prone initially, but population decline is steeper if alpha is greater than a fixed value alpha d. 3. Periodic, sexual repair at system-specific intervals prevents continuous decline and stabilizes the population insofar as it will now oscillate between two fixed population levels. 4. The stabilizing sexual interval increases with increased complexity provided this is accompanied by appropriate levels of redundancy. 5. The model closely simulates the dynamics of heterosis effects. 6. Repair fitness is a population fitness: the chance of an individual being repaired is a function of the statistical make-up of the population as a whole at the particular period. Populations living at alpha greater than alpha c either engage in sexual repair at the appropriate time or they die out. 7. The mathematical properties of the model illustrate mechanisms which possibly played a role in the evolution of a mortal soma in relation to sexual reproduction.

Animals↗
PubMed1978

Viral studies in streptozotocin-induced pancreatic insulitis.

Multiple injections of streptozotocin to Charles River (CD-1) Laboratory mice resulted in a syndrome characterised by diabetes mellitus, insulitis and the induction of endogenous type C viruses in pancreatic beta cells. Within one week after the completion of five intraperitoneal injections of streptozotocin, the CD-1 mice exhibited irreversible hyperglycaemia and insulinopaenia. Light microscopic studies of pancreata from mice sacrificed at this time demonstrated insulitis and beta cell necrosis. Electron microscopic studies revealed spherical and atypical cylindrical type C viruses and occasional clusters of intracisternal type A viruses exclusively within beta cells. To clarify the identification of the type C viruses and their role in the genesis of the insulitis, type C virus specific antigens were identified within islet cells by immune fluorescence at various intervals after streptozotocin administration. Immune fluorescence studies demonstrated the presence of type C virus antigens within islets from streptozotocin treated mice but not in buffer-injected controls. Time course studies suggested that type C virus induction may precede the appearance of insulitis by two days and that insulitis is consistently accompanied by the presence of virus positive islet cells.

Animals↗
PubMed1978

Angiography in the diagnosis of renal allograft dysfunction.

We reviewed retrospectively 75 renal transplant arteriograms done during a 7-year period. Acute rejection and vasomotor nephropathy were not differentiated. Generalized cortical ischemia was diagnosed correctly in 23 of 30 cases but there were 7 falsely negative results. Renal artery stenosis was found in 7 of 17 cases in which the main indication for arteriography was hypertension. We conclude that the major role of transplant arteriography is in the diagnosis of larger vessel disease.

Adolescent↗
PubMed1978

Increased frequency of HLA-DRW4 in chronic active hepatitis.

HLA-A, B, C and DRw typing was performed on peripheral blood lymphocytes of 17 adults with the diagnosis of chronic active hepatitis made by liver biopsy as the only criterion for study. An increase in the frequency of HLA-DRw4 (71 vs. 24%, p less than 0.005) was observed, but there was no increased frequency of HLA-A1, B8 or any other HLA locus specificity.

Adult↗