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Biomedical subjects

B Larsen

Publications and source records attributed to B Larsen.

At least 253 records · Page 14Linked to original sources
PubMed1977

HLA in familial Hodgkin's disease. Results and a new hypothesis;.

A familial aggregate of seven cases of Hodgkin's disease (HD) has been investigated by HLA typing. Over 600 people in the immediate population (i.e. about half) have been HLA typed and haplotypes have been obtained for 95% of them. It was expected that the cases would share a particular HLA haplotype or at least that they would have one or two HLA antigens of the same series in common. However, this was not the case so no simple idea of association of HLA with HD cases was upheld. When antigen frequencies were examined in the whole population, it was found that HLA B18 increased progressively in incidence from 0.08 to 0.4 in successive groups of individuals each one more closely related to the HD cases. Similarly the community with the highest incidence of HD also had the highest incidence of B18. Thus B18, which in the world figures carries the highest relative risk, emerged as important in this study. Of four proposed interpretations of the data, we are most interested in the idea that the important HLA association is at a population level rather than at the level of the individual patient. A hypothesis, based on the concept of a "healthy carrier" for the HD agent, explains how such an association might operate. It is possible that B18-linked complement deficiency could be the basis for such a carrier state.

Antigens, Neoplasm↗
PubMed1977

Redistribution of polycations bound to lymphocytes.

The redistribution of surface-bound polycations on human lymphocytes and mouse-spleen lymphocytes was studied by fluorescence microscopy. A redistribution pattern after incubation with protamine, polylysine and DEAE-dextran resembling patching and capping processes was observed both at 20 degrees C and at 4 degrees C. The interaction between polycations and the cell surface is considered to represent non-specific binding to the membrane proteins. The redistribution process is regarded as precipitaion processes. This is in accordance with the finding that no effect on the binding and redistribution of polycations was noticed in the presence of NaN3, vinblastine sulphate, vincristine sulphate, colchichine, cytochalasin B or trypsin treatment. When incubation periods longer than 5 min. were employed beginning internalization of flourescent material is observed. Interaction with the nuclear membrane similarly resulted in rearrangements and capping.

Animals↗
PubMed1977

Cerebral hemodynamics in migraine.

Clinical and angiographic findings in migraine are briefly reviewed in relation to cerebral hemodynamic changes shown by regional cerebral blood flow (rCBF) studies. Three cases of migraine studied by the intracarotid xenon 133 method during attacks are reported. In classic migraine, with typical prodromal symptoms, a decrease in cerebral blood flow has been demonstrated during the aura. Occasionally, this flow decrease persists during the headache phase. In common migraine, where such prodromata are not seen, a flow decrease has not been demonstrated. During the headache phase of both types of migraine, rCBF has usually been found to be normal or in the high range of normal values. The high values may represent postischemic hyperemia, but are probably more frequently secondary to arousal caused by pain. Thus, during the headache phase rCBF may be subnormal, normal or high. These findings do not exclude the possibility of distension of the larger intracranial arteries during migraine headache, but the angiographic evidence, however limited, does not support this speculation.

Adult↗
PubMed1977

Bf types of HLA haplotyped individuals in an isolated Newfoundland population.

Five hundred and fourteen individuals from an isolated NewFoundland population have been typed and haplotyped for HLA and Factor B (Bf locus). The Bf gene frequencies were: S0.704, F0.226, F1 0.052 and S1 0.018. Tracing the haplotypes backwards on the various pedigrees it was shown that 202 HLA/Bf haplotypes had been introduced into the study population. Some HLA alleles always appeared in association with particular Bf alleles and vice versa. Bf S1 had entered the population four times, always with HLA--A9, B12. Bf F1 had entered three times, always with HLA--B18. There were 17 entries of HLA--Al, B8 that had given rise to the 78 such haplotypes that were now present in the population; all were Bf S. There were 68 family units informative for Bf. They accounted for 240 children and 304 informative meioses. There were three recombinants in the HLA region but none could be shown to have occurred between the HLA-B and Bf loci.

Adult↗
PubMed1977

Scanning electron microscopy of vaginal colonization.

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.

Animals↗
PubMed1977

Relationship of vaginal cytology to alterations of the vaginal microflora of rats during the estrous cycle.

The influence of cyclic changes occurring in the vaginal tract during the estrous cycle upon the indigenous microflora of the vagina has been investigated by semiquantitative techniques in virgin female rats. By plate counts performed on material lavaged daily from the vaginal tract of several rats, it is apparent that bacterial counts are elevated in the proestrus and estrus phases of the cycle to values several orders of magnitude greater than those observed during metestrus or diestrus phases. Increases in vaginal bacterial counts were associated with the presence of cornified epithelial cells in the vagina; these cells were predominantly nonviable. Decreases in the vaginal bacterial content were related to the influx of leukocytes into the vagina after estrus. When leukocytes were present in the vaginal tract, they were 90 to 100% viable. From these observations it has been concluded that the female vaginal tract and the bacteria which colonize it represent a dynamic ecosystem which is responsive to cyclic events occurring in the estrous cycle. The changing cellular content of the vaginal tract may have relevance to the observed cyclic changes in the bacterial content of the vagina.

Journal Article↗
PubMed1977

Spatial relationship of the vaginal microflora to the vaginal epithelium of female rats: scanning electron microscopy.

The vaginal mucosa of ovariectomized female rats has been examined by scanning electron microscopy before and after estrogen [1,3,5(10)-estratriene-3,17beta-diol] treatment. Without estrogen stimulation vaginal colonization is minimal and the epithelium is characterized by a layer of epithelial cells covered with small microvillous-like projections. Progressive changes that were consistent with estrogenic cytoproliferative effects were seen after estrogen treatment. By post-treatment day 3 bacterial colonization was maximal and the epithelium was comprised of flat squamous cells that tended to become detached from the underlying tissue layers. Bacteria were seen in association with the intercellular borders of this tissue and occurred singly or as microcolonies. No distinct physical attachment structures were identified, although an amorphous extracellular material that may serve to attach the bacteria to the squamous epithelial cells was frequently seen.

Animals↗
PubMed1977

Role of estrogen in controlling the genital microflora of female rats.

Plate counts of viable bacteria recovered by lavage from rat vaginae demonstrated that the number of bacteria associated with the vaginal epithelium varied cyclically and that this pattern was abolished by ovariectomy. After ovariectomy, vaginal bacterial counts remained relatively stable at low levels. The estrogen 17beta-estradiol (1,3,5(10)-estratriene-3,17beta-diol cypionate) administered to ovariectomized rats caused a significant increase in vaginal bacterial counts on day 3 post-treatment. A similar effect was seen in non-ovariectomized rats, but a larger dose of estrogen antagonist may have been present in non-ovariectomized animals. Progesterone (4-pregnene-3,20-dione) given with estradiol diminished the effect of the estrogen on vaginal bacterial counts, but did not abolish it. Progesterone administered without estradiol had no detectable effect on vaginal bacterial counts. These findings suggested that the cyclic variation in bacterial content of rat vaginae could be explained primarily as the effect of the secretory pattern of ovarian estrogen.

Animals↗
PubMed1977

Skin perfusion pressure measured as the external pressure required to stop isotope washout. Methodological considerations and normal values on the legs.

The skin perfusion pressure was measured as the external pressure required to stop blood flow, as evidenced by cessation of the washout of an intracutaneous depot of [131I-]antipyrine mixed with histamine. The external pressure on the skin was measured by an 11 x 11 cm slack air-filled plastic cushion connected to a mercury manometer and interposed between the labelled area and a blood pressure cuff. The 'flow cessation external pressure' (FCEP) varied parallel to the intra-arterial femoral mean blood pressure, but was on the average 10.8 mmHg (SD 6.4) lower. FCEP was measured on twenty normal subjects at four different segments of the leg. The average differences between auscultatory brachial mean blood pressure and FCEP were: thigh 12.0 mmHg (SD 7.6); calf 10.4 mmHg (SD 7.4); ankle 12.9 mmHG (SD 10.1); foot 20.2 mmHg (SD 12.1). The SD of the difference between measurements on two different days, performed in forty-four patients with different degrees of occlusive arterial disease, varied between 5.6 and 8.3 mmHg at the different levels. The present data indicate that the skin perfusion pressure on the legs in normal subjects lies approximately 10 mmHg lower than the systemic mean arterial blood pressure.

Arterial Occlusive Diseases↗
PubMed1977

Regional cerebral blood flow alterations remote from the site of intracranial tumors.

Regional cerebral blood flow (rCBF) was investigated in 12 patients with brain tumors, using a 254-channel dynamic gamma camera. In nine of the 12 cases, hyperemic regions with loss of autoregulation were seen in sites remote from the tumor (the area around the tumor was in most cases also hyperemic). These remote rCBF abnormalities were found in the lower posterior part of the hemisphere in six cases, and in the frontal region in three. The location of the remote rCBF abnormality seemed to depend on the site of the tumor: cases with frontal and posterior fossa mass lesions had hyperemia in the lower part of the temporooccipital regions, cases with centroparietal mass lesions had hyperemia mostly in the frontal region. This may mean that the remote rCBF abnormality is due to local tissue compression against unyielding anatomical structures, namely, the tentorium and the falx. It is suggested that these abnormalities may constitute evidence of an early stage of a dangerous clinical condition: a state of preherniation.

Aged↗
PubMed1977

rCBF in aphasia.

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Aphasia↗