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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 991 records · Page 55Linked to original sources
PubMed1982

Steroid control of gonadotrophin secretion in the orchidectomized dog.

The effects of s.c. administration of oil, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol and oestradiol-17 beta on plasma concentrations of LH and FSH were determined in 5 orchidectomized dogs. The dosages for the androgens and oestradiol-17 beta were 500 and 50 micrograms/kg body weight, respectively. Testosterone and oestradiol-17 beta significantly reduced plasma gonadotrophin concentrations, although the onset and duration of their suppressive effects differed. Dihydrotestosterone and oil had no effect on either gonadotrophin. Administration of androstanediol had no effect on plasma concentrations of LH but did cause a temporary and significant reduction in FSH. It is concluded that testosterone and oestradiol-17 beta are major regulators of gonadotrophin secretion in the male dog, but the 5 alpha-reduction of testosterone seems to play only a minor role in this control.

Androstenediol↗
PubMed1982

Immunocytochemical localization of HLA-DR in human islets of Langerhans.

Previous reports of allogeneic transplantation studies in rodents have postulated that the primary carriers of Ia antigen in islets of Langerhans are passenger leukocytes. We sought to demonstrate directly the localization of the analogous human antigen, HLA-DR, in islet-enriched fractions (IEFs), utilizing a nonpolymorphic monoclonal anti-DR (alpha DR) antibody. The presence of DR in the IEFs was first demonstrated by radioimmunobinding assay. Light microscopic immunocytochemistry, in frozen sections of intact (unfixed) human pancreas, revealed a staining pattern suggestive of a vascular distribution of DR in islets. Ultrastructural localization of DR was then carried out by indirect immunoperoxidase labeling in the presence of NaN3 (to prevent internalization of bound alpha DR). The major site of DR expression in the islet was the endothelial cell surface. Endocrine cells were entirely devoid of alpha DR binding. Nonislet endothelium was also heavily labeled, but acinar and ductal cells were completely negative. Leukocytes bound alpha DR but were relatively rare in the IEFs. Human islets, therefore, clearly express HLA-DR, but predominantly on insular endothelial cells. Isolation of pure endocrine cell populations, specifically free of endothelium, would appear to be a rational approach to reducing immunogenicity in allogeneic transplantation.

Antibodies, Monoclonal↗
PubMed1982

The nervous control of rat somatostatin, glucagon and insulin secretions.

Somatostatin-like-immunoreactivity (SLI), immunoreactive insulin (IRI), glucagon (IRG) and catecholamine concentrations were measured in rat portal plasma during electrical stimulation of the vagus and splanchnic nerves, and during experimentally-induced hypovolaemia and hypoxaemia. Blood pressure, arterial gases and pH were monitored and hepatic blood flow was estimated (EHBF). Stimulation of the vagus nerves induced an increase in IRG and IRI concentrations, but had different influences on SLI level according to the concomitant experimental conditions. Stimulation of the left splanchnic nerve induced a sharp rise in SLI, IRG and catecholamine concentrations, whereas IRI level decreased hypovolaemia and hypoxaemia. Phentolamine treatment augmented the basal IRI, IRG and SLI concentrations. It did not suppress the hypovolaemia-induced rise of IRG and SLI concentrations, but unmasked a strong IRI release. By contrast, propranolol and atropine reduced significantly the A and D cell responses to acute hypovolaemia. These results are consistent with a profound influence of pancreatic nerves on A, B and D cell functions, which should be taken into account for interpretation of results during in vivo experiments.

Animals↗
PubMed1982

Effects of histocompatibility testing versus immunoreactive predisposition on kidney transplant survival.

From January 1979 to August 1981, 76 primary renal transplants were performed at the University of Miami-Jackson Memorial Hospital. Fifty-five of these were from living, related (LR) donors and 21 were from cadaver (CAD) donors. Histocompatibility typing for HLA-A, -B, and -DR antigens and of mixed lymphocyte culture (MLC) were performed. In LR patients the ability to generate donor-specific and nonspecific suppressor cells in vitro was tested preoperatively. Serial posttransplant immunologic monitoring was used in all patients by determining total T-cell numbers (E rosette-forming cells) as well as helper and suppressor T-cell subsets by use of monoclonal antibodies. Overall patient and graft survival was 90% and 87%, respectively. In this study MLC reactivity did not correlate with DR typing in CAD recipients, most of whom had marked reaction despite one or two DR antigen matches. Graft survival was also independent of MLC reactivity in both LR and CAD patients. The ability of LR recipients to generate donor-specific suppressor cells in vitro before transplantation did correlate significantly with absence of rejection episodes. Immunologic monitoring with T-cell subsets had prognostic significance for the detection of patients with excessive immunosuppression and high risk for development of infection (P less than 0.001). Thus, the responder status of many transplant recipients seemed as important as the current assessment of histocompatibility in influencing graft survival.

Antibodies↗
PubMed1982

Maternal anti-fetal cytotoxic antibody responses of equids during pregnancy.

The maternal immunological response to the developing equine fetus was investigated in 69 pregnancies of various genotypes. In normal intraspecies horse pregnancy (N = 16), 94% of mares produced strong cytotoxic antibody responses to paternal histocompatibility antigens which were first detectable between 44 and 70 days after ovulation. In all other types of pregnancy examined (intraspecies donkey, N = 19; interspecies mule, N = 6; interspecies hinny, N = 2; extraspecies horse-in-donkey, N = 3; and extraspecies donkey-in-horse, N = 21), antibody production was observed less frequently, and sometimes with a more irregular onset. However, the dominant pattern of response was similar to that observed in intraspecies horse pregnancy. Although the development of cytotoxic antibody correlated well with the formation of the equine endometrial cups, histological and serological evidence demonstrated that the accumulation of lymphocytes which occurs around the endometrial cups in intra- and interspecies pregnancies, and in the endometrial stroma in contact with trophoblast in extraspecies donkey-in-horse pregnancies which lack endometrial cups, can occur in the absence of a detectable cytotoxic antibody response. The cytotoxic antibody produced by mares carrying extraspecies donkey conceptuses appeared to be directed primarily against donkey alloantigens, and not species-specific antigens, emphasizing the importance of maternal recognition of paternally derived fetal histocompatibility antigens during equine pregnancy.

Animals↗
PubMed1982

Strength of the cement-bone interface.

The fixation of total joint components to bone using acrylic bone cement is by the penetration of the cement into the microstructure of cancellous bone to achieve a mechanical interlock. It has been shown that the method of cement application and the preparation of the cancellous surface significantly affects both the tensile and shear strengths of the cement-bone interface. Doughy cement finger-packed on an uncleaned surface resulted in a very low interface strength compared to a low-viscosity cement made to penetrate a cleaned bone surface. Maximum strengths were achieved for cancellous bone cleaned by using either a high-intensity water lavage or a polyethylene brush and by facilitating penetration of the cement for distances of 5 to 10 mm into the bone.

Biomechanical Phenomena↗
PubMed1982

Artificial insemination with fresh donor semen using the cervical cap technique: a review of 278 cases.

Two hundred twenty-six patients received artificial insemination with fresh donor semen (AID) using the cervical cap technique; 52 patients underwent the procedure for 2 conceptions. Using life-table analysis to adjust for uneven patient follow-up, the cumulative pregnancy rate was 62.5% after 6 months of AID, and 82.4% after 10 months. Moreover, using a mathematical model of cumulative pregnancy following AID, the estimated cure rate was not significantly different from 100%, and the estimated monthly probability of pregnancy among those cured was 15.5%. Age was found to be inversely related to pregnancy success, while parity had no effect. For those who continued to undergo AID beyond 6 months, the monthly probability of pregnancy did not decline. Patients can be advised that their chance of conception with AID should approach that of normal fertile couples.

Adult↗
PubMed1981

Auditory brainstem responses in postconcussion syndrome.

Evidence that head injuries can shear nerve fibers and end bulbs in the tracts between the diencephalon and brainstem led us to hypothesize that auditory brainstem responses might be abnormal in patients with postconcussion syndrome. We recorded brainstem responses in 11 patients and 12 control subjects. Comparing the two populations, our chief finding was that the patients showed significant delays for wave 3. This finding indicates organic changes involving a region at least as central as the superior olivary complex, thus refuting many authors' claims that the syndrome is entirely psychogenic.

Adult↗
PubMed1981

The role of chromosome 15 in murine leukemogenesis. I. Contrasting behavior of the tumor vs. normal parent-derived chromosomes No. 15 in somatic hybrids of varying tumorigenicity.

G-banding analysis was carried out on a series of hybrids derived from the fusion of a chromosome 15-trisomic murine T-cell leukemia of AKR origin and normal diploid fibroblasts or lymphocytes of the CBT6T6 strain. Due to the 14;15 translocation involved in the generation of the T6 marker, the chromosomes No. 15 and 14 derived from the normal and the tumor parent can be distinguished cytogenetically. Highly tumorigenic, in vitro maintained hybrids, and high-tumorigenic segregants of originally low-tumorigenic in vitro hybrids, selected by in vivo passage, showed a similar cytogenetic pattern. It was characterized by the amplification of the tumor-derived chromosomes No. 15 from the expected 3 to 5.5 +/- 0.2 copies and a concomitant decrease of the normal derived T(14;15)6 from 2 copies to 0.9 +/- 0.2. All other autosomes except No. 14 showed only minor random variations, around the expected number of 4 copies. The tumor-derived chromosome 14 was amplified from the expected 2 to 3 copies. The low-tumorigenic hybrids showed the opposite pattern with a decrease in the number of the tumor-derived 15 chromosome from 3 to 2.6 +/- 0.1 and the maintenance of the two normal parent derived T(14;15)6 chromosomes. These findings suggest the existence of a qualitative difference between the 15 chromosomes derived from the tumor vs. the normal parent, due to mutation or proviral DNA insertion in the tumor-derived homologue. Amplification of the change locus and a decrease in the dosage of its normal counterpart appear to favor tumorigenicity.

Animals↗
PubMed1981

The assessment of adolescent hallux valgus before and after first metatarsal osteotomy--clinical and walkway studies.

A comprehensive method of evaluating the feet of patients with adolescent hallux valgus both before and after surgical correction is described. Serial clinical, photographic and radiological studies were made and a dynamic assessment of gait was carried out using a load-sensitive walkway. Observations were made on 36 feet in which hallux valgus was treated by a modification of the Wilson oblique metatarsal osteotomy, with removal of a wedge of bone and screw fixation. In the first six months after operation, there was a lateral shift of the weight-bearing pattern in the forefoot and less weight was taken on the toes, but there was a tendency to return to the pre-operative distribution of weight during the next four years. Persistence of the lateral shift of weight-bearing appeared to result from elevation of the first metatarsal head secondary to shortening of the first metatarsal during the osteotomy. This can be avoided by deliberate depression of the first metatarsal head at the time of operation and fixation of the fragments in the required position with a screw.

Adolescent↗
PubMed1981

Population studies of leukocyte-reactive antinuclear antibody and HLA antigens.

The prevalence of serum leukocyte-reactive antinuclear antibody (LR-ANA) was determined in 31 patients with ankylosing spondylitis (AS), their age-and gender-matched normal controls, and two tribes of 340 West Coast Canadian Indians (Bella Coolas and Haidas). At a serum dilution of 1 : 10, the prevalence of LR-ANA in AS and controls was 45% and 7%, respectively. At 1 : 20 dilution, the prevalence was 23% in AS, 0% in controls, 29% in Bella Coolas and 27% in Haidas. No concordance was found among LR-ANA, HLA-B27 and CREG-B7, and nine HLA-A and seven HLA-B antigens in the Indian tribes. These studies confirm an increased prevalence of LR-ANA in AS and AS kindreds, but the latter association appears to be independent of HLA antigens.

Antibodies, Antinuclear↗
PubMed1981

Garré's proliferative periostitis occurring simultaneously in four quadrants of the jaws.

Typically, Garré's osteomyelitis affecting the jaws is unilateral and is restricted to the mandible. We are reporting a case in which all four quadrants were involved, an occurrence which we believe must be extremely unusual and has not been reported previously. Conservative management over a period of 3 years resulted in complete resolution, with return of normal facial and osseous contours.

Child↗
PubMed1981

Irrelevant differences in the "same"--"different" task.

This article examines the effects of irrelevant information on the multidimensional "same"--"different" task. Subjects were instructed to compare two geometric figures with respect to certain attributes but to ignore other attributes in making the "same"--"different" decision. The irrelevant attributes were chosen in such a way that they could not easily be ignored to see how the existence of irrelevant differences would affect the comparison process. As expected, the overall latencies were longer than is usually found in tasks with no irrelevant differences. However, the nature of the comparison process appeared unchanged. The usual finding of a "fast-same" phenomenon persisted even when irrelevant information was present. The similarity of the results in this task to results in the "same"--"different" task with no irrelevant features supports the idea that the same comparison mechanism is used whether or not irrelevant differences are present in the stimulus pairs. The results suggest a more general-purpose comparison mechanism than is usually included in models of this task. Two-process models of visual comparisons are thus ruled out entirely. A modified version of Krueger's noisy-operator theory does appear consistent with the results.

Discrimination Learning↗