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Biomedical subjects

G Baldwin

Publications and source records attributed to G Baldwin.

At least 19 recordsLinked to original sources
PubMed2000

Continuing medical education habits of US women physicians.

OBJECTIVES: To quantify the time women physicians spend on continuing medical education (CME) in total and by type of activity and to assess the impact of various demographic and professional characteristics on CME practices. METHODS: We analyzed CME habits among 4501 female physicians (a 59% response rate) using a 1994 national questionnaire-based survey, the Women Physicians' Health Study. RESULTS: US women physicians reported spending a monthly mean of 12.5 hours on CME, including 5.1 hours reading medical journals, 3.1 reading medical textbooks, 3.7 attending live CME lectures, 0.7 listening to CME audio tapes, and 0.4 watching medical television or videos. They also spent 0.9 hours per month learning from lay health media. Physicians with subspecialty training, medical school employment, and a non-US birthplace reported significantly (p < 0.05) more CME hours; age, ethnicity, region, specialty type, practice locale, career satisfaction, and board certification did not significantly predict reported CME hours. CONCLUSIONS: US women physicians reported spending an average of one-half hour each work day on CME, including about one hour per week reading medical journals, their most commonly reported CME activity.

Education, Medical, Continuing↗
PubMed1999

Puncture wounds.

Puncture wounds are common in children, and most are uncomplicated. For children who have a delayed presentation or signs of infection, consider the possibility of a retained foreign body. The diagnosis of P aeruginosa osteochondritis should be considered in any child who exhibits persistent signs and symptoms after puncture wounds; timely use of laboratory tests, radiologic imaging, and orthopedic referral is required.

Anti-Bacterial Agents↗
PubMed1999

Intranets are the key to new database strategies.

Health care organizations are finding that easy-to-use intranets can improve access to data. Because intranets are easier to navigate than other networks--and often less expensive--many provider and payer organizations are reorienting their database plans. But some organizations move too fast with new plans and have difficulty standardizing enterprisewide data, threatening intranet viability.

Computer Communication Networks↗
PubMed1998

U.S. women physicians' residential radon testing practices.

INTRODUCTION: These analyses were designed to elucidate U.S. physicians' perception of residential radon risk, as measured by the prevalence of residential radon testing using a representative sample of U.S. women physicians from the Women Physicians' Health Study database. In addition, characteristics of women physicians who were more likely to have conducted a residential radon test were identified. METHODS: A random sample (n = 4,501 respondents) of U.S. women physicians aged 30 to 70 was obtained in the Women Physicians' Health Study. Analyses were conducted using SUDAAN. RESULTS: The overall prevalence of residential radon testing among respondents was 18%, 2- to 6-fold higher than any estimate of residential radon testing in the general population. The strongest relationship with radon testing observed through logistic regression was with marital status; age, ethnicity, and region of residence were also related. CONCLUSION: The study demonstrates that although U.S. women physicians are more likely to have conducted a personal residential radon test than the general population, 82% report not having done so. Increasing the awareness of physicians about the health risks associated with prolonged radon exposure will be essential if they are to play a role in addressing this important public health problem.

Adult↗
PubMed1998

Ex vivo expansion and differentiation of unselected peripheral blood progenitor cells in serum-free media.

The ability to expand and differentiate unselected PBPC was investigated. Cells were grown in serum-free media containing stem cell factor, GCSF and megakaryocyte growth and development factor (pegylated PEG-rHuMGDF) with or without supplemental serum. Optimal proliferation occurred when PBPC were cultured without prior Ficoll-Paque separation in serum-free media. Cell yields after 17 days of culture were proportional to the percentage of CD34+ cells in the starting population and were 1170+/-302-fold higher than the starting numbers of CD34+ cells. Granulocyte-macrophage colony-forming units increased over 12 days of culture, whereas the numbers of erythroid colony-forming cells peaked between 4 and 7 days. Elimination of PEG-rHuMGDF from cell cultures resulted in significantly lower yields of myeloid and erythroid colony-forming cells and total cell numbers. Cell differentiation into neutrophils was indicated by progressive increases in CD11b, CD15, and CD66b expression. Expanded neutrophils phagocytosed and killed bacteria as efficiently as neutrophils from normal donors. Large-scale expansion studies yielded similar proliferation and differentiation results as parallel small-scale cultures. Therefore, unselected PBPC can be efficiently expanded and differentiated into large numbers of functional mature neutrophils.

Antigens, CD↗
PubMed1997

Lexically-based learning and early grammatical development.

Pine & Lieven (1993) suggest that a lexically-based positional analysis can account for the structure of a considerable proportion of children's early multiword corpora. The present study tests this claim on a second, larger sample of eleven children aged between 1;0 and 3;0 from a different social background, and extends the analysis to later in development. Results indicate that the positional analysis can account for a mean of 60% of all the children's multiword utterances and that the great majority of all other utterances are defined as frozen by the analysis. Alternative explanations of the data based on hypothesizing underlying syntactic or semantic relations are investigated through analyses of pronoun case marking and of verbs with prototypical agent-patient roles. Neither supports the view that the children's utterances are being produced on the basis of general underlying rules and categories. The implications of widespread distributional learning in early language development are discussed.

Age Factors↗
PubMed1996

Calcium binds dynamin I and inhibits its GTPase activity.

Synaptic vesicle recycling is a neuronal specialization of endocytosis that requires the GTPase activity of dynamin I and is triggered by membrane depolarization and Ca2+ entry. To establish the relationship between dynamin I GTPase activity and Ca2+, we used purified dynamin I and analyzed its interaction with Ca2+ in vitro. We report that Ca2+ bound to dynamin I and this was abolished by deletion of dynamin's C-terminal tail. Phosphorylation of dynamin I by protein kinase C promoted formation of a dynamin I tetramer and increased Ca2+ binding to the protein. Moreover, Ca2+ inhibited dynamin I GTPase activity after stimulation by phosphorylation or by phospholipids but not after stimulation with a GST-SH3 fusion protein containing the SH3 domain of phosphoinositide 3-kinase. These results suggest that in resting nerve terminals, phosphorylation of dynamin I by protein kinase C converts it to a tetramer that functions as a Ca(2+)-sensing protein. By binding to Ca2+, dynamin I GTPase activity is specifically decreased, possibly to regulate synaptic vesicle recycling.

Animals↗
PubMed1996

Regulation of HIV-1 infection in astrocytes: expression of Nef, TNF-alpha and IL-6 is enhanced in coculture of astrocytes with macrophages.

'Restricted' human immunodeficiency virus type (HIV-1) infection of astrocytes is recognized in vivo in some pediatric and adult AIDS brains and in vitro in a small proportion of transfected primary fetal astrocytes. We investigated the extent of HIV-1JR-FL expression in fetal astrocytes and macrophages cultivated alone or together. Peak HIV-1 p24 antigen titres in supernatant fluids of macrophage cultures were increased with monocyte/macrophages from certain donors and were higher when macrophages were cocultivated with astrocytes. Structural HIV-1 gene (gp 41 and pol) products (protein and mRNA) were observed only in macrophages. Ten days after HIV-1JR-FL infection, astrocytes in a monoculture were stained negative or only weakly positive (1-2+) for Nef, whereas in a coculture up to 100% of astrocytes displayed Nef staining (up to 4+) in the cytoplasm. The streptavidine-biotine-peroxidase technique with certain monoclonal antibodies to Nef (Ovod et al, 1992) was specific for infected astrocytes. The intensity of Nef staining was higher in astrocytes cultivated with monocyte/macrophages from certain donors. In the coculture, tumor necrosis factor-alpha (TNF-alpha) was expressed in the astrocyte cytoplasm earlier after coinfection with HIV-1 and cytomegalovirus (CMV) compared to infection with HIV-1 alone. Interleukin-6 (IL-6) was secreted spontaneously and transiently in uninfected cocultures, but in a prolonged fashion following HIV-1 and HIV-1/CMV infections. The interactions between HIV-1- and CMV-infected macrophages and astrocytes lead to upregulation of TNF-alpha and IL-6 and enhancement of productive HIV-1 infection of macrophages and of 'restricted' HIV-1 infection of astrocytes with implications for the pathogenesis of AIDS dementia.

Astrocytes↗
PubMed1996

Murine IL-10 fails to reduce GVHD despite inhibition of alloreactivity in vitro.

Graft-versus-host disease (GVHD) is a serious complication following allogeneic bone marrow transplantation (BMT). Initial immunologic events that are thought to lead to clinical GVHD include allogeneic antigen presentation, CD4+ T cell proliferation and eventually generation of specific cytotoxic lymphocytes. Interleukin-10 (IL-10) has been shown to inhibit the function of antigen presenting cells (APC) and to reduce lymphocyte proliferation. In this study we investigated the possible role of recombinant murine IL-10 (rmIL-10) as prophylactic treatment of GVHD in a murine BMT model involving B10.BR donor mice (H-2k) and AKR recipients (H-2k). In particular, we wished to determine whether early post-BMT administration of IL-10 would suppress GVHD by interfering with macrophage function and inflammatory cytokine production during the proposed "afferent' phase of GVHD. In MLR assays, rmIL-10 significantly inhibited the proliferation of donor spleen cells when stimulated by irradiated recipient spleen cells in a dose-dependent manner. In murine BMT, rmIL-10 was administered exogenously by intraperitoneal injection of 100 U daily in two different dosage schedules, on days-1, 0, 1, 2, 3, 6 to target the early post-BMT phase, and days-1, 0, 3, 5, 7, 10 after BMT, to administer the same total dose throughout the engraftment period. IL-10 injected mice had lower plasma IL-1 alpha levels on day 3 (12 pg/ml vs 64 pg/ml in controls, P < 0.05), suggesting that both macrophage function and inflammatory cytokine production were inhibited. In contrast to the MLR data, no significant improvement in morbidity and mortality from GVHD was observed. Therefore, IL-10 does not appear to be useful in GVHD prophylaxis.

Animals↗
PubMed1993

Sexual abuse and body-image distortion in the eating disorders.

It has been suggested that there is a link between sexual abuse and bodily self-deprecation in women with eating disorders. In order to test that model, this study considers whether reported sexual abuse is associated with body-image distortion in anorexia and bulimia nervosa. There was no association with the reported presence of a history of abuse. However, the nature of any abuse was important. In particular, women who reported more recent abuse had a substantially greater level of bodysize overestimation. The clinical implications of this finding are discussed.

Adolescent↗
PubMed1992

Limulus antilipopolysaccharide factor protects rabbits from meningococcal endotoxin shock.

Limulus antilipopolysaccharide factor (LALF), an 11.8-kDa peptide isolated from amebocytes of Limulus polyphemus, neutralizes meningococcal lipooligosaccharide (LOS)-induced gelation of limulus amebocyte lysate. Rabbits challenged with an LD90 of LOS (10 micrograms/kg) premixed with LALF in vitro (n = 10) had significantly higher mean arterial pressure, arterial pH, serum bicarbonate concentrations, and survival (90% vs. 8%, P = .005) than did rabbits challenged with LOS alone. Relative to untreated controls, rabbits pretreated with LALF intravenously (iv) at 1.2 mg/kg (n = 21) also had significant improvements in physiologic measurements and higher survival (52% vs. 8%, P = .003). Even when LALF (1.2 mg/kg iv) was given 1/2 h after LOS challenge, animals showed significant improvements in physiologic measurements and survival (33% vs. 8% in untreated controls P = .028). LALF-treated animals also had significantly lower circulating endotoxin activity and tumor necrosis factor concentrations. Thus, LALF attenuates the toxic effects of meningococcal LOS in rabbits even when administered after LOS challenge and deserves further evaluation as a potential therapeutic agent for treating gram-negative septic shock.

Animals↗
PubMed1992

Effect of a human immunoglobulin preparation for intravenous use in a rabbit model of meningococcal endotoxin-induced shock.

BACKGROUND AND METHODS: Endotoxin shock is mediated by various cytokines, including tumor necrosis factor. Treatment of patients with i.v. immunoglobulin has been shown to reduce the concentration of circulating cytokines. The purpose of this study was to determine the protective effects of immunoglobulin for i.v. use on meningococcal endotoxin-induced shock in a rabbit model. Experimental animals were challenged with i.v. meningococcal endotoxin (lipo-oligosaccharide) 10 micrograms/kg, and treated with either a 2-hr i.v. immunoglobulin infusion (400 mg/kg) or a similar saline infusion that was initiated 30 mins before endotoxin challenge. Control animals were challenged with saline alone. RESULTS: Compared with untreated control animals, pulse rate increased (p less than .007) and mean arterial pressure and serum bicarbonate concentrations decreased (p less than .02) in both experimental groups, but did not differ between immunoglobulin-treated and saline-treated animals (p greater than .05) at any time after the endotoxin challenge. Geometric mean serum endotoxin concentrations were significantly (p less than .03) lower in the immunoglobulin-treated animals at 60, 120, 180, 240, 300, and 360 mins after the endotoxin challenge. The geometric mean serum tumor necrosis factor level at 1 hr after the endotoxin challenge in the immunoglobulin-treated experimental animals was lower than in saline-treated animals (5.53 vs. 8.47 tumor necrosis factor enzyme-linked immunosorbent assay U/mL), but not significantly so (p greater than .05). Mortality rate was similar in both experimental groups; eight (67%) of 12 saline-treated experimental rabbits and seven (70%) of ten immunoglobulin-treated rabbits died. All untreated control animals survived 24 hrs. CONCLUSIONS: In this model of circulatory shock in rabbits, i.v. immunoglobulin: a) does not significantly alter the physiologic responses to endotoxin challenge; b) significantly reduces endotoxin concentrations; c) reduces tumor necrosis factor concentrations, but not significantly; and d) does not improve survival rate.

Analysis of Variance↗
PubMed1992

Effect of meningococcal endotoxin in a rabbit model of shock.

Endotoxin in the form of a lipooligosaccharide (LOS) plays a key role in the development of shock in meningococcal sepsis. To examine hemodynamic and biochemical alterations during meningococcal endotoxic shock, we established a rabbit model. Thirty-nine rabbits, weighing 2.5-4.4 kg, were studied. After anesthesia with intramuscular ketamine (20 mg/kg) and xylazine (4 mg/kg), femoral venous and arterial catheters were inserted. Control animals received only saline, while rabbits in each of four additional groups were given LOS in 10-fold increments from 0.1 microgram/kg to 100 microgram/kg. Mean arterial pressure (MAP), heart rate (HR), respirations (RR), temperature (T), urine output, and arterial blood gases (pH, PCO2, PO2, and bicarbonate) were determined at baseline and hourly. Endotoxin levels and TNF levels were measured at 30, 60, 120, 180, 240, 300, and 360 min post-LOS. Survival was recorded. One-way analysis of variance (ANOVA) and the Scheffe procedure, paired samples t-test, two-tailed t-test, and Fisher's exact test were used. Pearson's coefficients were calculated. Animals receiving meningococcal LOS developed tachycardia and compensated metabolic acidosis with an initially normal pH and MAP. With progression of the shock state, the pH decreased and hypotension ensued. Maximal levels of endotoxin were measured 30 min after LOS injection and declined during the ensuing 6 hr. TNF rose from undetectable to markedly elevated levels and peaked at 60-120 min post-LOS. Increasing the amount of injected endotoxin produced more profound degrees of shock until a dose of 10.0 micrograms/kg was reached. There was no correlation between serum TNF at 60 min and survival at 6 hr or 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗