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Biomedical subjects

B Mitchell

Publications and source records attributed to B Mitchell.

At least 19 recordsLinked to original sources
PubMed1992

Failed self-tolerance and autoimmunity in IgG anti-DNA transgenic mice.

Transgenic mice were generated that express both the H and L chain genes derived from a hybridoma secreting an IgG2a mAb specific for ds- and ssDNA. This hybridoma is derived from a lupus mouse and can accelerate nephritis in young NZB x NZW F1 female mice and induce clinical nephritis in BALB/c mice. Some transgenic B cells did not exhibit allelic exclusion; they expressed both transgene-derived IgG and endogenous IgM intracellularly. Most of the B cells in transgenic mice expressed endogenous IgM, some of them expressed low levels of IgG on cell membranes. The transgenic mice, created in a strain not prone to SLE, expressed elevated serum IgG anti-DNA, and some developed clinical nephritis. The affinity of the spontaneously secreted IgG antibodies for dsDNA were similar in nephritic NZB x NZW F1 and transgenic mice. In contrast to the nontransgenic littermates, immunization of transgenic mice with murine DNA further enhanced serum levels of IgG anti-DNA in transgenic mice. Therefore, expression of transgene-encoded IgG anti-DNA mainly in the secreted form does not provide the signals necessary for allelic exclusion or self-tolerance. Expression of this Ig is sufficient to induce a mild form of autoimmune disease.

Animals↗
PubMed1992

Prostate adenocarcinoma using Gleason scores correlates with prostate-specific antigen and prostate acid phosphatase measurements.

To evaluate a relationship between Gleason scores of histopathology of prostate carcinoma and concurrent serum prostate-specific antigen (PSA) and prostate acid phosphatase (PAP) values, 65 men with prostate carcinoma were studied. These patients' cumulative Gleason scores were obtained by totaling the primary and secondary patterns, resulting in two groups: 42 patients received high (6-10) and 23 received low (2-5) Gleason scores. Serum PSA and PAP values were measured by radioimmunometric assay 1 to 7 days before surgical procedures or biopsy for prostate carcinoma. Mean serum PSA for patients in the high Gleason score group was 134.39 ng/mL (normal range: 0 to 4), and the mean serum PSA for patients in the low Gleason score group was 23.62 ng/mL. Mean serum PAP for patients with high scores was 28.08 ng/mL (normal range: 0 to 5), and the mean serum PAP for patients with low scores was 18.19 ng/mL. Patients with high Gleason scores showed significantly greater elevation of serum PSA than those with low Gleason scores (P = .047), using two samples to test for groups having unequal variants. Prostate acid phosphatase levels of patients with high scores were not significantly higher than the levels in patients with low scores (P = .60). These results indicate that PSA levels but not PAP levels correlate with Gleason scores.

Acid Phosphatase↗
PubMed1991

Prediction of radionuclide bone imaging findings by Gleason histologic grading of prostate carcinoma.

To evaluate a relationship between Gleason scores and Tc-99m HMDP bone imaging findings, data from 48 men (aged 45 to 77; mean, 67) with prostate carcinoma who had a bone imaging study at the time of presentation were reviewed. Cumulative Gleason scores were divided into two groups: high scores (6-10), 32 men; low scores (2-5), 16 men. Of the 32 men with high Gleason scores, 15 tested positive for multiple metastases and 17 tested negative. Tumors of the 16 men with low Gleason scores were negative for metastasis. A chi-square association between Gleason scores and the presence of metastases, either of a superscan pattern or multiple metastases, was 10.9 (1 df, P less than 0.001). The results indicate that a superscan pattern or multiple metastases were found exclusively in the bone images of patients with high histologic grades; bone images negative for metastases were associated with low-grade tumors. We conclude that positive bone imaging for metastases at the initial scan occurs only in patients who have high Gleason scores, that patients with high Gleason scores might or might not have skeletal metastasis, and that skeletal metastasis is not predictable in patients with low Gleason scores.

Adenocarcinoma↗
PubMed1979

Calcium, magnesium, and growth control in the WI-38 human fibroblast cell.

WI-38 and SV40WI-38 cells have been synchronized using centrifugal elutriation. This technique allows for the rapid harvesting of early G1 phase cells from exponentially growing populations of both the normal and transformed cell. Using these cells, as well as WI-38 cells synchronized by serum deprivation, we have examined the effects of extracellular Ca and Mg levels on the progression of cells through G1 phase. A differential sensitivity to both Ca and Mg deprivation is observed between normal and transformed cells. The WI-38 cell requires higher levels of both ions for traversal of G1 phase and for continued proliferation as compared to the transformed cell. The temporal nature of the Ca and Mg requirements for the WI-38 cell has been examined during G1 phase. Ca is strictly required during early and late G1 phase, but not necessarily throughout mid-G1. An early as well as a late G1 Ca requirement is also found in serum-stimulated WI-38 cells. In contrast, the Mg requirement of WI-38 cells does not appear to be temporally well-defined. Mg appears to be a permissive factor, required throughout G1 phase rather than at certain prescribed intervals. On the basis of these data, it seems unlikely that these two cations exert their effects on cell growth entirely through a common competitive mechanism. Ca would appear to be involved in early serum or growth factor-mediated G1 events and later pre-S-phase events, as suggested in previous studies on other cell lines.

Calcium↗
PubMed1979

Small intestinal morphology and epithelial cell kinetics in lamb rotavirus infections.

Morphologic changes in the small intestine of rotavirus-infected gnotobiotic lambs were investigated by measurement of villi and crypts in histologic sections of jejunum, midgut, and posterior ileum. In midgut, villus atrophy developed within 12 hr of infection and was apparent until 72 hr after infection. Crypt hypertrophy was evident from 42 hr after infection until the end of the observation period (6 days after infection). Changes in posterior ileum were similar in extent, but jejunal changes were much less marked. The relatively mild effect in the jejunum is in accord with reports from other species, and provides a basis for questioning the assumption that human rotavirus affects mainly the foregut. Studies of epithelial cell kinetics were made on midgut using a microdissection and metaphase accumulation technique on sequential samples from anesthetized lambs. An increase in the cell production rate per crypt per hour from the overall control level of 5.8 was detected by 48 hr after infection. The maximum level of 21.2 was reached 8 days after infection, and this had returned to near normal by 15 days after infection. This large and sustained increase in crypt cell production probably underlies other previously described functional abnormalities.

Animals↗
PubMed1978

Surgical techniques for the serial sampling of cerebrospinal fluid and for electrocorticography in cattle.

During the investigation of a familial neurological disease of cattle with some similarities to human epilepsy serial sampling of lateral ventricular and cisternal cerebrospinal fluid and of electrocortical activity was undertaken. In this paper the surgical approach, the technical problems encountered and some solutions are discussed. Further possibilities for the development and application of the technique are indicated.

Animals↗
PubMed1977

Uridine diphosphate galactose 4'-epimerase deficiency. IV. Report of eight cases in three families.

Eight persons who had no activity of uridine diphosphate galactose 4'-epimerase in their circulating blood cells are known today. They were healthy members of three different families. Propositi were newborns discovered in a mass screening test for blood galactose which registered high levels of erythrocyte galactose-1-phosphate. Epimerase deficiency was restricted to circulating blood cells, but in liver biopsy specimens, in cultured skin fibroblasts and in activated lymphocytes epimerase was found to be normally active. Heterozygotes had intermediate red cell epimerase activity. There were no symptoms of galactose intolerance and no pathology related to the enzyme defect. All 8 epimerase deficient persons had a ccdee Rhesus genotype. Attempts at demonstrating genetic linkage between the epimerase and Rhesus loci were unsuccessful because of the difficulty encountered in ascertaining epimerase heterozygosity. Individuals with hereditary UDP-galactose 4'-epimerase deficiency appear to produce an unstable mutant enzyme requiring higher NAD concentration for maximum activity.

Aged↗
PubMed1976

Rewarming from immersion hypothermia: a comparison of three techniques.

Rewarming from immersion hypothermia has been assessed in sheep by the use of three techniques--hot bath, body insulation and airway warming. Though the hot bath was the fastest of the methods of rewarming studied, consideration of temperature gradients and therefore total body heat diminished its advantage in comparison with central body rewarming via the airway (CBRW), which in turn showed considerably advantage over body insulation alone. CBRW did not have any thermal advantage gained on assisting the ventilation as compared with spontaneous breathing. The results illustrate the importance of adequate insulation of the body to prevent further heat loss and this was found to be true whether or not airway warming was being used. The site of heat uptake with CBRW was determined and observations were made on the physical behaviour of temperature gradients.

Animals↗
PubMed1976

"Bicarbonate resistant" metabolic acidosis in association with ethylene glycol intoxication.

A case of massive ingestion of ethylene glycol is described. The clinical characteristics of this disorder such as persistent metabolic acidosis and oxaluria as well as changes in serum osmolality that may accompany ingestion of certain toxins are emphasized. The rapid clearance of ethylene glycol from the blood during hemodialysis is noted and the use of ethyl alcohol to block metabolic conversion of ethylene glycol to oxalic acid, which is also a toxin, is described. The importance of early diagnosis and therapy is stressed.

Acidosis↗
PubMed1976

Is a moral consensus in medical ethics possible?

At the moment in Britain and elsewhere the debate inside and outside of Parliament on various medical issues which are essentially moral never ends. Everybody has his own point of view--or principles. But what emerges for society to adopt can often be called in lay terminology 'compromise'. Professor Mitchell argues in this paper that a moral consensus is possible and indeed ought to be achieved, as today the medical practitioner can no longer make his decision only in accordance with the strict code of ethics of the medical profession. The task of the philosopher, says Professor Mitchell, is to interpret the actions and attitudes demanded by modern medical practice.

Abortion, Legal↗