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Biomedical subjects

K Clark

Publications and source records attributed to K Clark.

At least 19 recordsLinked to original sources
PubMed1992

A national model of faculty development in addiction medicine.

Increasing the number of faculty with expertise in addiction medicine is one of the challenges facing the medical community in the 1990s. To meet this challenge, the Society of Teachers of Family Medicine created a faculty development course to increase the expertise of family practice faculty involved in teaching residents. The authors describe the development, implementation, and consequences of the five-day intensive course that was taught to 165 participants at ten sites in 1990. The participants' self-reporting before and three months after the course showed significant increases in the numbers of participants who taught addiction medicine in eight of 11 clinical situations. The authors conclude that the course represents a model of faculty development in addiction medicine that is applicable to other specialties and health professions.

Evaluation Studies as Topic↗
PubMed1992

Renal allograft rejection: induction and function of adhesion molecules on cultured epithelial cells.

The interaction of graft-infiltrating immune cells with donor parenchymal cells is an important early event in allograft rejection. This binding is stabilized by interaction of antigen-independent 'adhesion' molecules expressed on the two cell types. As the level of expression of these molecules can be altered during inflammation, a series of experiments was performed to examine the effects of the inflammatory cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) on adhesion molecules expressed by cultured human renal tubular epithelial cells. These cells constitutively expressed ICAM-1 and LFA-3. Incubation with IFN-gamma increased expression of ICAM-1 but had no significant effect on expression of LFA-3 (P greater than 0.05). Incubation with TNF-alpha increased expression of both ICAM-1 and LFA-3; IFN-gamma synergized with TNF-alpha to further augment expression of these molecules. Peripheral blood lymphocytes (PBL) showed an enhanced binding to allogeneic renal epithelial cell monolayers which had been pretreated with IFN-gamma or TNF-alpha. MoAbs specific for ICAM-1 or its ligand LFA-1 inhibited adhesion of PBL to either IFN-gamma- or TNF-alpha-pretreated renal cells. By contrast, antibodies specific for LFA-3 or its ligand CD2 only significantly blocked PBL adhesion to renal cells which had been pretreated with TNF-alpha. Combination of antibodies specific for multiple components of the adhesion systems produced greater inhibition of adhesion than was produced by any single MoAb. These results suggest that the inflammatory cytokines IFN-gamma and TNF-alpha up-regulate expression of functional ICAM-1 and LFA-3 molecules which can augment the binding of potentially graft-damaging lymphoid cells to renal tubular epithelial cells.

Antigens, CD↗
PubMed1992

Differences in lingual vibrotactile threshold shifts during magnitude-estimation scaling between normal-speaking children and children with articulation problems.

The purpose of this study was to investigate differences in function of the tactile sensory system between groups of normal-speaking children and children with articulation problems. This task was accomplished by studying possible tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. 10 normal-speaking children (M age = 7.8 yr.) and 9 children with articulation problems (M age = 7.5 yr.) participated. The normal-speaking children and articulatory defective children performed differently on the magnitude-estimation scaling task in which threshold was allowed to return to baseline after each stimulus presentation. These two groups of children also showed dissimilar threshold shifts for the suprathreshold intensities employed in the magnitude-estimation scaling.

Articulation Disorders↗
PubMed1991

The accuracy of self-reported hearing loss in women aged 60-85 years.

The accuracy of self-report in identifying individuals with hearing impairment was evaluated in 1988 in 267 women from rural Iowa. Using pure-tone threshold audiometry as the standard, self-reported hearing loss was a sensitive and specific indicator of measured losses of 40 decibel hearing level for pure-tone averages of either 1,000 and 2,000 Hz or 1,000, 2,000, 3,000 and 4,000 Hz (sensitivities, 90% and 84%; specificities, 71% and 75%, respectively). Predictive values positive were low (28% and 42%) in this population where hearing loss prevalence was 11-18%, but would be increased to acceptable levels in populations with a prevalence of approximately 30%.

Aged↗
PubMed1991

Unexplained rabies in three immigrants in the United States. A virologic investigation.

BACKGROUND: Extensive investigation of three patients who died of rabies in the United States failed to reveal any source of exposure to the disease. The three patients had immigrated to the United States from areas in Laos, the Philippines, and Mexico where rabies is endemic. METHODS: We studied rabies viruses isolated from the three patients, other patients with a known source of exposure, and animals in the United States, Thailand (as a proxy for Laos), the Philippines, and Mexico. The viruses were characterized by indirect immunofluorescence and neutralization tests according to their reactions to panels of monoclonal antibodies. Transcribed complementary DNA from these isolates was amplified by the polymerase chain reaction; the DNA product was then analyzed by differential digestion with restriction enzymes. RESULTS: The viral isolate from each of the three patients was a rabies variant with distinctive antigenic or genetic characteristics. For each of the three isolates, identical variants were found in specimens from rabid animals obtained from or near the country in which the patient lived before immigrating to the United States. None of these variants were found among the isolates collected from rabid animals in the United States. CONCLUSIONS: Rabies infection in these three patients did not originate in the United States but resulted from exposures in Laos, the Philippines, and Mexico. Since the three patients had lived in the United States for 4 years, 6 years, and 11 months, our findings suggest that the onset of the clinical manifestations of rabies occurred after long incubation periods.

Adolescent↗
PubMed1991

Factors influencing the ocular pulse--axial length.

The amplitude of the intraocular pressure pulse and pulsatile ocular blood flow (POBF) were correlated with the axial length and refraction of 68 eyes of healthy subjects. Measurements were obtained with subjects in the sitting position using an ophthalmic A-scan and a pneumotonometer linked to a Langham ocular blood-flow system. The amplitude of the ocular pulse and the magnitude of POBF were found to decrease with increasing axial length (r = -0.61, P less than 0.001 and r = -0.74, P less than 0.001, respectively). A similar close relationship was found between the ocular pulse amplitude and POBF and the refractive state of the eye (r = 0.63, P less than 0.001 and r = 0.7, P less than 0.001, respectively). The reasons for the association are discussed and the importance of the observations in the construction of studies in which ocular pulse amplitude or POBF are to be measured in different groups of subjects is emphasised.

Adolescent↗
PubMed1991

A prospective study of physical trauma and multiple sclerosis.

During an eight year period 170 multiple sclerosis (MS) patients and 134 controls without physical impairment were followed closely to record all episodes of physical trauma and to measure their effect on exacerbation rate and progression of MS. There was a total of 1407 instances of trauma, which were sorted into various categories. Overall there was no significant correlation between all-traumas and disease activity. There was, however, a statistically significant negative correlation between traumatic episodes and exacerbations in 95 patients who had exacerbations during the programme, due primarily to less activity of the disease during a three month period following surgical procedures and fractures. Electrical injury had a significant positive association with exacerbation using a three month at-risk period, but there were no other significant positive correlations in any other category of trauma, including minor head injuries; there were no cases of head injury with prolonged unconsciousness. There was no linkage between the frequency of trauma and progression of disability. MS patients had two to three times more trauma than controls.

Adult↗
PubMed1991

Renal allograft rejection: investigation of alloantigen presentation by cultured human renal epithelial cells.

Defined lines of primary human renal epithelial cells were established and their expression of class II major histocompatibility (MHC) antigens was up-regulated by culture with interferon-gamma (IFN-gamma). The ability of these cells to stimulate the proliferation of allogeneic peripheral blood mononuclear cells (PBMC) was compared with that of endothelial cells and splenic mononuclear cells. It was found that both endothelial and splenic cells stimulated lympho-proliferation but that cultured renal epithelial cells were non-stimulatory. The failure of proliferation by allogeneic lymphocytes in culture with epithelial cells was not overcome by treatment with interleukin-1 (IL-1) or indomethacin. However, addition of IL-2 to mixed cultures of allogeneic PBMC and renal epithelial cells stimulated lympho-proliferation and allowed the generation of lymphoid cell lines which mediated non-specific lysis of renal epithelial cell lines. Stimulation of PBMC by mixed lymphocyte culture yielded an allospecific T-cell line which was added either to renal epithelial cells from the same donor as the stimulator cells used in the priming reaction or from a third-party donor; lympho-proliferation was observed in the specific secondary reaction but not in the non-specific reaction. These findings indicate that class II MHC antigen-expressing epithelial cells within a renal allograft may not initially stimulate the proliferation of resting allospecific recipient lymphocytes. However, within a rejecting graft it is likely that high local concentrations of IL-2 are present and that many of the infiltrating allospecific lymphocytes will be primed by previous contact with donor antigen-presenting cells, such as vascular endothelial cells or dendritic cells. Therefore, expression of class II MHC antigens by epithelial cells within the microenvironment of a renal allograft may render such cells immunogenic and able to play a direct role in the lymphocyte-mediated intragraft rejection process.

Antigen-Presenting Cells↗
PubMed1978

Clinical studies of intrathecal autologous lymphocyte infusions in patients with malignant glioma: a toxicity study.

The feasibility and toxicity of intrathecal lymphoid cell infusions in patients with glioma were examined in this study. Blood rich in lymphoid cells was obtained using the Haemonetics Model 30 cell separator; the lymphoid cells extracted were further purified on Ficoll-Hypaque gradients. Four patients received a total of eighteen autologous lymphoid cell infusions, with between 1 X 10(6) and 5 X 10(9) lymphoid cells being infused on each occasion. No toxicity was observed, but the CSF glucose declined in 2 patients. In 1 patient examined at autopsy the lymphoid cells appeared to have gained access to the tumor bed as well as to the rest of the subarachnoid space.

Astrocytoma↗
PubMed1977

Transsphenoidal microsurgery for selective removal of functional pituitary microadenomas.

The transphenoidal approach to the pituitary gland is emerging as the safest and most efficacious procedure for the management of pituitary tumors. With the aid of the microscope large tumors producing visual symptoms can be removed and microadenomata producing only signs and symptoms of endocrinopathies can be safely and adequately approached. The procedure is described in this report. The results of its use in 29 patients with selected illustrative case reports are described.

Acromegaly↗
PubMed1977

Cerebral revascularization for transient ischemic attacks.

Thirty-one patients with cerebral transient ischemic, attacks and ipsilateral internal carotid artery occlusion without contralateral internal carotid artery occlusion or stenosis were treated with a surgical anastomosis between a superficial temporal artery and a cortical branch of the middle cerebral artery of the symptomatic hemisphere. The anastomosis was successful in 28 patients. Recurrent transient ischemic attacks were abolished in 23 patients and reduced in three. Two patients, one with a patent anastomosis, had strokes during the follow-up period. Of seven patients who refused the operation, two had strokes, two noted a reduction of transient ischemic attacks, two noted no change, and one became asymptomatic.

Adult↗
PubMed1977

Assessing adolescent mental health needs: the views of consumers, providers, and others.

The perceived mental health needs of adolescents were measured by questionnaire to groups of teenagers, parents, community child guidance personnel, self-help groups, police and court related people, school personnel, mental health administrators and area board members. Alcohol abuse and unemployment were seen as the first and second priority problems by most groups. Regarding specific services and facilities needed, residential facilities of various types were the most critical concern. Alcohol abuse programs, employment counseling, and family therapy and counseling were also major needs. There was considerable consensus as to needs among both consumers and providers. However, consumers tended to see as higher priority those problems affecting large numbers of adolescents while providers worried more about the seriously disturbed few.

Adolescent↗