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Biomedical subjects

W Smith

Publications and source records attributed to W Smith.

At least 235 records · Page 13Linked to original sources
PubMed1991

Improving a community preceptorship through a clinical faculty development program.

A department of family and community medicine has successfully used annual conferences to develop the teaching skills of clinical faculty. The conferences focus on specific topics each year, faculty are required to attend, and experienced preceptors are used as facilitators. These conferences have effectively improved the preceptors' abilities as teachers of medical students. This is dramatically illustrated by the increase in measurable objectives on the negotiated learning contracts.

Community Medicine↗
PubMed1991

Interleukin-2 receptors on rat eosinophils in adjuvant arthritis.

Monoclonal antibodies specific for the interleukin-2 receptor (IL-2R) have been used to demonstrate by immunohistochemical methods the presence of IL-2R on eosinophils as well as on lymphocytes in lymphoid tissue taken from rats with adjuvant arthritis. Evidence is presented which suggests that the IL-2R on eosinophils may have been induced by the disease process.

Animals↗
PubMed1990

DEL cell line: a "malignant histiocytosis" CD30+ t(5;6)(q35;p21) cell line.

A new cell line DEL, established in vitro, was isolated from a pleural effusion of a boy who died of malignant histiocytosis. Its principal characteristics are: strong positivity with monoclonal antibodies (MAbs) to CD25, CD30, CD45R, KiM7, EMA, HLA Cl I and II; constant presence of acid phosphatase, ANAE, alpha-anti-trypsin, alpha-anti-chymotrypsin and NBT reductase activity; rearrangement of the immunoglobulin heavy-chain gene (JH) and a germ-line configuration of the T-chain gene; and finally a translocation between chromosomes 5-6 with a breakpoint in 5q35. The DEL cell line is appropriate for studying the role of the 5q localized c-fms oncogene and of the genes of the mononuclear phagocyte growth factor (CSFI) and of their receptors in the dynamics and etiology of malignant hemopathies associated with a 5q35 breakpoint.

Antigens, Neoplasm↗
PubMed1990

Serial abuse in children who are shaken.

Serious injury can occur to children who are shaken, especially if the shaking is repeated or part of a pattern of abuse. Serial abuse in connection with children who are shaken and their siblings has important therapeutic and legal ramifications. From an ongoing study of child abuse and head trauma, 12 of 24 victims of shaking that resulted in intracranial injury were identified who had coexisting evidence of direct external trauma. Seventeen children (71%) had evidence of prior abuse, neglect, or both, including 8 who had multiple intracranial hemorrhages. Of the 21 families represented, 9 had more than one child, 3 (3%) of which had several siblings who had been victims of child abuse. Shaking of children usually is not an isolated event, as it frequently has been preceded by other types of abuse.

Brain Injuries↗
PubMed1990

Incidence of impact trauma with cranial injuries ascribed to shaking.

Shaking as a mechanism of severe brain injury in infants has been challenged on a theoretical basis as insufficient to explain the magnitude of observed injuries. Computed tomography and magnetic resonance imaging, developed since shaken baby syndrome was first described, are helpful in establishing whether external trauma occurred for infants thought to have been shaken. We compiled data from 24 infants initially diagnosed as having shaken baby syndrome, including physical examination, roentgenograms, computed tomography or magnetic resonance imaging, and autopsy (when applicable). Half of the patients showed no evidence of direct impact, and evidence of external trauma was not predictive of a fatal outcome. These findings indicate that shaking by itself is sufficient to cause severe or fatal intracranial injury and that the shaken baby syndrome reflects a spectrum of such child abuse injuries that may include direct trauma or only shaking.

Brain Injuries↗
PubMed1990

Suppression of well-established tumour xenografts by a hybrid-hybrid monoclonal antibody and vinblastine.

The hybrid-hybrid monoclonal antibody 28-19-8 has specificity for the tumour-associated antigen carcinoembryonic antigen and the vinca alkaloids. This bifunctional antibody has been used to target unmodified vinblastine sulphate to well-established MAWI human tumour xenografts implanted in nude mice. The highly significant suppression of tumour growth achieved throughout treatment has also been sustained for over 2 months after the withdrawal of treatment. Histological examination of excised tumours from treated animals has shown profound changes in their morphology when compared with tumours from control animals. Cells in tumours that had started to grow again after withdrawal of therapy were shown still to express carcinoembryonic antigen, the target antigen recognised by the bispecific antibody.

Adenocarcinoma↗
PubMed1990

Murine model of ethanol-induced immunosuppression.

Alcohol abuse has been associated with an increased susceptibility to infectious diseases and certain tumors. On the basis of these observations, an effect of ethanol on the immune system has been suggested. We have used a mouse model system in which male C57Bl/6 mice were fed either Lieber-DeCarli liquid diet containing ethanol sufficient to supply 37% of the total calories or isocaloric control diet in a pair-feeding design to examine the effect of ethanol on the immune system. The group consuming the ethanol-containing diet maintained relatively stable levels of blood ethanol for the 8 days of feeding. Consumption of ethanol for 8 days resulted in a profound loss of thymus and spleen cells, and the recovery of thymus cellularity was delayed relative to the recovery of spleen cell numbers after ethanol feeding was discontinued. Proliferation of spleen lymphocytes to T-cell stimuli (concanavalin A and alloantigens) was diminished; however, B-cell proliferation to lipopolysaccharide was relatively unchanged in mice fed ethanol-containing diet. Also in ethanol-fed mice a significant decrease in the primary antibody response to sheep red blood cells but not to the T-independent antigen trinitrophenol-ficoll occurred. These data establish the murine model system as a means to define further the effect of ethanol on the immune system and host defense mechanisms.

Alcoholism↗
PubMed1990

Regulating professional services in ICFs/MR: remembering the past and looking to the future.

Generally, our society regulates from a standpoint of failure in the system. When the field of mental retardation could not adequately monitor its own professional practices, litigation and legislation brought the onset of government intervention. Historically, consensus building has been the method by which standards emerge and then become adopted into regulation. Yet at best, this practice results in "opinions" as to how quality should be defined. The Health Care Financing Administration's experience in regulating and enforcing has resulted in an emphasis on the outcomes of services received by individuals. Though difficult, it challenges professionals to begin defining accountable measures of "quality" over time.

Behavior Therapy↗
PubMed1990

Serial Munchausen syndrome by proxy.

Five cases of Munchausen syndrome by proxy (MSBP) are presented in which more than one child in the family was victimized. There was a high incidence of maternal psychiatric histories, marital difficulties, and Münchhausen syndrome in the mothers themselves. Seventy-one percent of the children in the families were known to be victims of MSBP; four of these children (31%) died. Multiple-child MSBP may reflect more significant maternal psychopathology than found in other cases of MSBP, or it may indicate the deteriorating consequences to the mother and other children in the family if this syndrome is not identified with the first child and effective interventions made.

Apnea↗
PubMed1990

Defining successful performance among pediatric residents.

The pediatric literature has documented a growing attention to defining the nature and quality of residency training. The critical incident technique, a method widely accepted in industrial settings, was used in this study to determine attitudes and behaviors deemed critical for successful performance of residents in a pediatric training program. Structured interviews with 17 senior teaching faculty produced descriptions of resident behavior that were classified into the following mutually exclusive categories: commitment to learning, clinical judgment, communicating medical information, recognition of limits, professional behavior, interpersonal skills with patients, and dealing with emergency situations. Only 30% of the critical incidents obtained from the faculty were related to criteria traditionally used to select and evaluate residents, such as knowledge and technical skills, while the remaining incidents were noncognitive in nature. The results of this study have implications for the evaluation and selection of residents and suggest that pediatric program directors and faculty must give attention to the means by which noncognitive skills are fostered in residents.

Attitude of Health Personnel↗
PubMed1989

Inhibition of neutrophil and natural killer cell function by human seminal fluid acid phosphatase.

The major acid phosphatase of human seminal fluid was purified to homogeneity by chromatography on Sephadex G-150, and DEAE-Sephadex, and by isoelectric focusing (pI, 4.3). This purified preparation of seminal fluid acid phosphatase blocked superoxide anion production by neutrophils stimulated with fMet-Leu-Phe (fMLP) by 50%. The phosphatase also hydrolysed myo-inositol 1,4,5-trisphosphate (IP3) in vitro, an intracellular second messenger which releases Ca2+ from intracellular pools, at nearly one-third the rate at which the nonphysiologic substrate 4-methylumbelliferylphosphate (MUP) was cleaved. In contrast, two phosphoinositide lipids, namely phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 4-monophosphate, were poor phosphatase substrates. Following fMLP stimulation of [3H]inositol-labeled neutrophils, the quantity of IP3 produced by phosphatase-treated cells was reduced by 69%. These results indicate that the human seminal fluid acid phosphatase may compromise the neutrophil's microbicidal response to the organism by hydrolyzing a second messenger (IP3) which is directly involved in the regulation of intracellular Ca2+ concentrations. The seminal fluid phosphatase also inhibited by 85% the ability of murine natural killer (NK) cells to inactivate target cells.

Acid Phosphatase↗
PubMed1989

Development of compliance chamber diaphragms with reduced permeability.

The implantable ventricular assist systems currently undergoing clinical readiness testing shuttle the displaced gas between the non-blood side of the pumping diaphragm and an elastic chamber generally called a "compliance chamber" or variable volume device. The movement of the stored gas allows the pump to fill and empty without compression or expansion of the gas behind the pump diaphragm. The material used for the construction of compliance chambers should be fatigue resistant to withstand the 63 million flexes per year of the blood pump. The material should also be biocompatible and highly impervious to gases. Significant diffusion of gases from the compliance system necessitates external make-up gases to somehow be added to the internal system. Material selection is complicated by the fact that most fatigue-resistant elastomers also have high gas permeability. In order to solve this problem, bilayer compliance chambers have been developed using biocompatible and fatigue-resistant polyolefin rubber comolded with relatively impervious butyl rubber.

Assisted Circulation↗
PubMed1989

Interleukin 2 responsive lymphocytes in patients with adenosine deaminase deficiency.

We evaluated the effects of recombinant interleukin 2 (IL-2) on the proliferative responses to mitogens of peripheral blood mononuclear cells (PBMC) from three adenosine deaminase (ADA)-deficient patients. There was significant enhancement by IL-2 of the proliferative responses to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) of PBMC from all three patients. We found that normal PBMC respond with increased numbers of CD3-positive cells when exposed to PHA or PWM and that the response by normal CD8-positive cells was greater than that by CD4-positive cells. In contrast, we found that in ADA-deficient cells the response is almost entirely due to the CD3/CD4-positive population of lymphocytes. These results could not be explained by either the culture conditions or the possibility of a mixed chimeric state. When we evaluated an in vitro cell model of ADA deficiency using an ADA inhibitor, erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), we found that the inhibitory effect of EHNA plus deoxyadenosine on mitogen-stimulated PBMC could not be prevented by IL-2. These results suggest that the immunodeficiency in ADA deficiency includes the absence or failure of a subset of T cells to make IL-2 and the failure of the CD8-positive subset to respond to IL-2. Also, the in vitro cell model of ADA deficiency using EHNA as the ADA inhibitor is limited in its use in understanding the pathogenesis of this disease.

Adenine↗