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Biomedical subjects

S Baker

Publications and source records attributed to S Baker.

At least 91 records · Page 5Linked to original sources
PubMed1997

History of violent behaviour and schizophrenia in different cultures. Analyses based on the WHO study on Determinants of Outcome of Severe Mental Disorders.

BACKGROUND: Information on patterns and correlates of the violent behaviour of individuals with schizophrenia is largely limited to populations in developed countries. Data from a World Health Organization epidemiological study of schizophrenia and related disorders, the Determinants of Outcome of Severe Mental Disorders (DOSMD), presented an opportunity to study patterns of violence across multinational settings. METHOD: Centres in 10 countries participated in the DOSMD study. An incidence sample of 1017 patients with schizophrenia who had their first-in-lifetime contact with a helping agency as a result of their psychotic symptoms was obtained. Data were available on their history of violent behaviour, substance use, and demographics. RESULTS: The occurrence rate of assault in the entire cohort was 20.6 per hundred, but the rate was three times higher in the developing countries (31.5 per hundred) than in developed countries (10.5 per hundred). History of assault was associated with positive symptoms, such as excitement and auditory hallucinations, and with serious alcohol problems. CONCLUSIONS: The cultural context and the specific characteristics of the disease in individuals with schizophrenia may interactively affect rates of violent behaviour.

Adolescent↗
PubMed1997

The relationships of self-care agency and self-care actions to caregiver strain as perceived by female family caregivers of elderly parents.

The relationships of self-care agency and self-care actions to perceived caregiver strain among female family caregivers of elderly parents were examined in this descriptive correlational study. The length of time in the caregiver role, the quantity of multiple roles, and types of caregiving tasks performed by the caregiver were examined with the self-care variables to note their association with caregiver strain. This study was based on Orem's (1991) conceptual model. A convenience sample of 131 primary caregivers completed. The Burden Interview, Denyes Self Care Agency Instrument and Denyes Self Care Practice Instrument by mail survey. Significant findings show an inverse relationship between self-care agency and caregiver strain; self-care actions mediated relationships between household tasks, emotional support, and caregiver strain; the moderating effects of multiple roles on self-care actions increased caregiver strain, and the moderator effects of personal care tasks on self-care actions decreased caregiver strain. These findings suggest the need for nurses to educate caregivers to use effective self-care actions and to assess for factors that may influence caregivers and affect caregiving outcomes.

Adult↗
PubMed1997

The epidemiology of fecal carriage of vancomycin-resistant enterococci.

An outbreak of vancomycin-resistant enterococci (VRE) began at the University of Massachusetts Medical Center in May 1993. As of September 1995, we had a total of 253 patients infected or colonized with VRE, with consequent increasing demand for private rooms. We analyzed results of surveillance cultures for VRE of 49 patients known to be colonized or infected with VRE. Of these, 34 (70%) were classified as persistent carriers, defined as patients with at least three consecutively positive cultures from any site taken over at least a 2-week period. The length of carriage varied from 19 to 303 days (median, 41 days); 11 patients were converters, defined as patients with three consecutive negative cultures from all previously colonized sites taken over a 3-week period. These patients were free of VRE for 39 to 421 days (median, 142 days). Four were recolonizers after they were documented to be clear of VRE for 33 to 106 days. VRE carriage tends to be prolonged, and hospitalization of patients with VRE will require continued isolation and contact precautions for control of transmission.

Carrier State↗
PubMed1996

Human non-pancreatic (group II) secreted phospholipase A2 expressed from a synthetic gene in Escherichia coli: characterisation of N-terminal mutants.

A gene coding for human non-pancreatic (group II) secreted phospholipase A2 (hnpsPLA2) has been constructed by the single-step ligation of twelve synthetic oligonucleotides. The gene has been cloned into a modification of the bacterial expression vector pET 11 which allows protein over-expression as inclusion bodies and enables about 3 mg/litre of pure refolded fully active enzyme to be obtained. The protein was expressed as a 1-Ala mutant (N1A) to allow removal of the initiator methionine by the Escherichia coli amino-peptidase. This mutant had very similar properties to the wild-type enzyme. A double mutant, N1A, V3W was also constructed and expressed in high yield. This tryptophan-containing mutant showed similar properties to the wild-type and N1A mutant but had about 40% of the activity under the assay conditions used. This tryptophan was used as a reporter group for interfacial binding and its properties were compared to those of the corresponding tryptophan in PLA2 from procine pancreas. Expression of the wild-type gene sequence for hnpsPLA2 in E. coli gave the expected mutant protein still with the initiator methionine and with much reduced activity. Interfacial binding of all hnpsPLA2 mutants to anionic phospholipids was very similar when assessed by fluorescence methods. Comparisons of these mutants with the pancreatic enzyme revealed significant differences in terms of the effect of calcium on interfacial binding. The ability to express reasonably large amounts of the N1A mutant in E. coli will provide a basis for future site directed mutagenesis studies of this important human enzyme.

Amino Acid Sequence↗
PubMed1996

Monoclonal antibody 197 (anti-Fc gamma RI) infusion in a patient with immune thrombocytopenia purpura (ITP) results in down-modulation of Fc gamma RI on circulating monocytes.

A 44-year old woman with refractory immune thrombocytopenia purpura was treated with the murine monoclonal antibody 197 in a phase 1 trial. It vitro studies have demonstrated that the monoclonal antibody 197 (subclass IgG2a) binds to two distinct epitopes of Fc gamma RI, with the constant domain binding to the Fc-binding portion of the Fc gamma RI and the variable domain binding to a different epitope, resulting in crosslinking and modulation of this receptor. The monoclonal antibody 197 was administered on days 1, 3 and 5 at doses of 0.25 mg/kg, 0.35 mg/kg and 0.45 mg/kg, respectively. The fusions were well tolerated with transient facial flushing, and wheal-and-flare rash during the first infusion, which resolved with a slower infusion rate and the administration of diphenhydramine and acetaminophen. Although a marked clinical improvement did occur with resolution of oral ecchymoses and epistaxis after the first mAb infusion, the initial platelet count of 6 x 10(9)/I did not change appreciable over the 5 d course of monoclonal antibody treatment. Binding of fluorescein-labelled monoclonal antibody 197 to peripheral monocytes showed a rapid and persistently decreased mean fluorescein intensity, indicated binding of administered 197 to the monocytes in vivo. Indirect staining for FcgammaRI using fluorescein-labelled goat anti-mouse immunoglobulin was also decreased, suggesting modulation of the receptor. The patient experienced monocytopenia which persisted throughout the 5 d of monoclonal antibody 197 therapy, but reversed following institution of intravenous IgG. These data indicate that intravenous monoclonal antibody 197 induces specific down-modulation of Fc gamma RI expression on monocytes.

Adult↗
PubMed1996

Muscle tenderness and peak torque changes after downhill running following a prior bout of isokinetic eccentric exercise.

Unaccustomed exercise (usually of an eccentric nature) is often followed by delayed onset muscle soreness (DOMS). Previous studies have found that prior eccentric activity produces a training effect which reduces DOMS and morphological changes. The aim of this study was to examine the effects of a prior bout of maximal isokinetic eccentric exercise on DOMS, strength loss and plasma creatine kinase (CK) changes following a downhill run. Ten male subjects with a mean (+/- S.D.) age of 22.5 +/- 2.8 years, body mass of 62.67 +/- 0.05 kg and height of 176 +/- 3 cm were allocated to either a treatment group or a control group. The treatment group performed 100 maximal eccentric activations of the knee extensors in the dominant leg at 0.52 rad s-1. Two weeks later, the downhill run was performed on a motor-driven treadmill. This consisted of five bouts of 8 min at a gradient of -10% at a speed corresponding to 80% of the predicted maximal heart rate. The untrained group performed the downhill run as above but without the prior isokinetic session. Tenderness measurements, plasma CK activity and concentric and eccentric isokinetic peak torque measurements of the knee extensors at 0.52 and 2.83 rad s-1 were recorded prior to, immediately following and 2, 4 and 7 days after each protocol. The isokinetic protocol caused an increase (P < 0.01) in CK and tenderness and a decrease (P < 0.05) in concentric and eccentric torque at both speeds in the treatment group. Following the downhill run, a reduction in peak torque (P < 0.01) was observed in the eccentric and concentric modes at both isokinetic speeds in the control group. For the treatment group, the decrease in peak torque occurred only at the faster eccentric speed. With the exception of the faster eccentric speed, the decrement in peak torque was greater in the control group in all post-exercise isokinetic strength tests. There was less tenderness (P < 0.01) in the trained knee extensor muscle group. Peak torque also returned to pre-downhill values earlier for the trained group. Although plasma CK activity increased in both groups after downhill running, it was much lower (P < 0.01) in the trained group. The results suggest that a prior bout of isokinetic eccentric training reduces muscle damage, reduces the amount of strength loss and decreases the sensation of DOMS after downhill running.

Adult↗
PubMed1996

Mutation of lysine residues in the nucleotide binding segments of the poliovirus RNA-dependent RNA polymerase.

The poliovirus 3D RNA-dependent RNA polymerase contains two peptide segments previously shown to cross-link to nucleotide substrates via lysine residues. To determine which lysine residue(s) might be implicated in catalytic function, we engineered mutations to generate proteins with leucine residues substituted individually for each of the lysine residues in the NTP binding regions. These proteins were expressed in Escherichia coli and were examined for their abilities to bind nucleotides and to catalyze RNA chain elongation in vitro. Replacement of each lysine residue in the NTP binding segment located in the central portion of the 3D molecule (Lys-276, -278, or -283) with leucine produced no impairment of GTP binding or polymerase activity. Substitution of leucine for Lys-61 in the N-terminal portion of the protein, however, abolished the binding of protein to GTP-agarose and all detectable polymerase activity. A nearby lysine replacement with leucine at position 66 had no effect on enzyme activity. The three mutations in the central region of 3D were introduced into full-length viral cDNAs, and the infectivities of RNA transcripts were examined in transfected HeLa cells. Growth of virus containing 3D with a mutation at residue 278 (3Dmu278) or 3Dmu283 was indistinguishable from that of the wild type; however, 3Dmu276 generated extremely slow-growing, small-plaque virus. Polyprotein processing by 3CDmu276 was unaffected. Large-plaque variants, in which the Leu-276 codon had mutated again to an arginine codon, emerged at high frequency. The results suggest that a lysine residue at position 61 of 3Dpol is essential for polymerase catalytic function and that a basic (lysine or arginine) residue at position 276 is required for some other function of 3D important for virus growth but not for RNA chain elongation or polyprotein processing.

Chromatography, Agarose↗
PubMed1996

A method of detecting the muscle pain threshold using an objective software-mediated technique.

This paper describes the reliability of a new procedure of applying force to a muscle site using a computer-mediated myometric procedure to measure a discomfort-pain threshold. 24 female subjects were divided into four groups. Each group was tested on three occasions (trial) at four muscle sites (site) repeated daily over four days (day). Each group received one of four different rates of force application (ramp). Analysis of variance (ramp by day by site by trial) showed a significant main effect for trials and discomfort-pain threshold at different muscle sites, but no significant main effect for days or ramps. Intraclass correlations for each muscle site were in the range of R = 0.73 to 0.98. This procedure appears to be a valid, reliable and nonintrusive means of assessing the muscle discomfort-pain threshold.

Adult↗
PubMed1996

Social support and patterns of adjustment to breast cancer.

The effect of marital support and support from other adults on the emotional and physical adjustment of 128 women with breast cancer was examined. Role function and satisfaction with health care also were evaluated as predictors of adjustment. Intact data series were obtained at 7-10 days, at 1, 2, 3, and 6 months, and 1 year postsurgery. Emotional adjustment could be predicted by satisfaction with a spouse's response to interactional and emotional needs and by support from other adults. The relationships were significant at concurrent times, across contiguous times, and predicting from the 7-10 day postsurgical period to both the 6-month and 1-year end points. Physical adjustment was not predicted by support but satisfaction with health care was predictive of perceived overall health status. Functional status in vocational, domestic, and social roles was significantly related to emotional and physical adjustment at all phases with few exceptions.

Adaptation, Psychological↗
PubMed1996

Sonographic appearance of the endometrium and ovaries during cycles stimulated with human menopausal gonadotropin.

OBJECTIVE: To determine the measurable factors that correlated with a higher conception ratio in one of our subpopulations of infertility patients. STUDY DESIGN: We analyzed 58 menstrual cycles in 24 consecutive infertility patients treated only with human menopausal gonadotropin (hMG) and intrauterine insemination between January 1992 and February 1993 to compare those cycles leading to conception with those that did not with regard to certain factors: endometrial thickness, endometrial layering, number of follicles > or = 15 mm in diameter, peak estradiol level and number of cycles prior to conception. RESULTS: All conceptions occurred in cycles that showed endometrial layering. No patient conceived if the endometrial thickness was < 8 mm. The incidence of conception increased with the number of follicles (one to three) measuring > 15 mm in average diameter. No patient conceived if the serum estradiol was < 192 pg/mL. No conceptions occurred after three successive cycles of treatment. CONCLUSION: Endometrial layering, endometrial thickness of at least 8 mm, a higher number of follicles (up to three) with an average of 15 mm and a serum estradiol level of at least 192 pg/mL correlated with a higher rate of conception.

Adult↗
PubMed1996

Production of fruits and vegetables at the homestead is an important source of vitamin A among women in rural Bangladesh.

BACKGROUND: Vitamin A deficiency is considered to be an important public health problem in Bangladesh. A universal biannual distribution of high-dose vitamin A capsules has been in place for over the past two decades. This supplementation has been beneficial for preschool children. Bangladesh has been exploring more sustainable approaches for all segments of the population. To support this initiative, Helen Keller International has implemented a homegardening promotion project since 1993. This project is executed on a large scale and currently reaches an estimated 244,000 families. METHODS: This paper presents data from 7341 women of reproductive age which were collected as part of the baseline census of a community monitoring system whose objective is to track progress and measure the impact of home-gardening activities. RESULTS: Vitamin A intake in this population derived almost entirely from the consumption of fruits and vegetables. Logistic regression analyses showed that maternal vitamin A intake was determined by qualitative indicators of homestead gardens (type of home garden, the total quantity of provitamin A-rich food produced and the number of fruits and vegetables varieties grown in the garden) after adjusting for socio-economic status. CONCLUSIONS: These results indicate that traditional production of provitamin A-rich fruits and vegetables in the homestead may provide a valuable contribution to vitamin A intake in communities where alternative dietary sources of vitamin A are scarce.

Agriculture↗
PubMed1995

Pesticide residues in urine of adults living in the United States: reference range concentrations.

We measured 12 analytes in urine of 1000 adults living in the United States to establish reference range concentrations for pesticide residues. We frequently found six of these analytes: 2,5-dichlorophenol (in 98% of adults); 2,4-dichlorophenol (in 64%); 1-naphthol (in 86%); 2-naphthol (in 81%); 3,5,6- trichloro-2-pyridinol (in 82%); and pentachlorophenol (in 64%). The 95th percentile concentration (95th PC) for 2,5-dichlorophenol (indicative of p-dichlorobenzene exposure) was 790 micrograms/liter; concentrations ranged up to 8700 micrograms/liter. 2,4-Dichlorophenol concentrations ranged up to 450 micrograms/ liter, and the 95thPC was 64 micrograms/liter. 1-Naphthol and 2-naphthol (indicative of naphthalene exposure) had 95thPCs of 43 and 30 micrograms/liter, respectively; concentrations of 1-naphthol ranged up to 2500 micrograms/liter. Chlorpyrifos exposure was indicated by 3,5,6-tricholoro-2-pyridinol concentrations of 13 (95thPC) and 77 micrograms/liter (maximum observed). Pentachlorophenol had a 95thPC of 8.2 micrograms/liter. Other analytes measured included 4-nitrophenol (in 41%); 2,4,5-trichlorophenol (in 20%); 2,4,6-trichlorophenol (in 9.5%); 2,4-dichlorophenoxyacetic acid (in 12%); 2-isopropoxyphenol (in 6.8%); and 7-carbofuranphenol (in 1.5%). The 95thPCs of these analytes were < 6 micrograms/liter. p-Dichlorobenzene exposure is ubiquitous; naphthalene and chlorpyrifos are also major sources of pesticide exposure. Exposure to chlorpyrifos appears to be increasing. Although pentachlorophenol exposure is frequent, exposure appears to be decreasing. These reference range concentrations provide information about pesticide exposure and serve as a basis against which to compare concentrations in subjects who may have been exposed to pesticides.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1995

Alpha 2-adrenergic receptor gene polymorphism and hypertension in blacks.

alpha 2-Adrenergic receptors are found on presynaptic neurons of the central and peripheral nervous systems, on blood vessels, on platelets, on adipocytes, and in the kidney and pancreas. Activation of these ubiquitous adrenoreceptors results in decreased neuronal norepinephrine release, vasodilation, a fall in blood pressure, platelet aggregation, increased sodium excretion, and decreased insulin release. We hypothesized that defects in alpha 2-adrenergic receptors, or postreceptor defects, could explain the increased prevalence of hypertension in blacks. To test our hypothesis, we first determined whether or not a polymorphism of the alpha 2-adrenergic receptor gene was associated with pathologic elevations in blood pressure in American blacks. Dra-I identified a restriction fragment-length polymorphism (RFLP) of 6.3 and 6.7 kb of the alpha 2-adrenergic receptor gene on chromosome 10 in humans. Of 227 patients studied, 13/107 hypertensive subjects were homozygous for the 6.3-kb allele, whereas only 3/120 normotensive volunteers were homozygotes (P = .008). When analyzed by race, 13/82 black hypertensive subjects were homozygous for the 6.3-kb allele, whereas only 2/59 normotensive blacks were homozygous for the 6.3-kb alleles (P = .02). However, only 1/61 white normotensive and 0/25 white hypertensive subjects were homozygous for the 6.3-kb allele (P = 1.00). Ethnic variation among blacks may explain our findings. Alternatively, a genetic polymorphism in, or near, the alpha 2-adrenergic receptor on chromosome 10 can contribute to the development of hypertension in blacks.

Alleles↗
PubMed1995

Should we treat localized prostate cancer? An opinion.

Localized prostate cancer is a progressive disease if left untreated. However, cancer-specific mortality is low in patients with moderately and well-differentiated prostate cancer treated with observation and delayed hormonal therapy, being 13% at 10 years and 20% to 30% at 15 years. By and large, radiation therapy does not appear to improve survival in these patients. With modern surgical techniques, mortality from prostate cancer is lowered by 23% to 65% in patients with moderately or well-differentiated tumors. However, the impact on relative cancer-specific survival is modest, since the mortality rate in untreated patients is low. The survival of conservatively managed patients with poorly differentiated prostate cancer is dismal: here radiation therapy or surgery significantly improves outcome. The QOL of patients with localized prostate cancer is significantly affected by the occurrence of distant metastasis. Metastatic rates are high in patients who are followed with observation and delayed endocrine treatment (19% to 85%). We were unable to deduce the effects of radiation therapy on grade-specific metastatic rates at 10 and 15 years. The only surgical series that addresses the issue shows a 50% to 80% reduction in metastatic rates. This results in an improvement in metastasis-free survival of 19% to 300%. The reduction in metastatic rates with surgery holds true for patients with poorly, moderately, or well-differentiated tumors. However, a significant proportion of the surgical patients were treated with adjuvant endocrine therapy, and it is impossible to identify the benefit from surgery and the benefit from adjuvant therapy. Radical prostatectomy improves survival in men who are 65 years or younger with moderately or well-differentiated adenocarcinoma of the prostate, and in men 75 years or younger who have poorly differentiated adenocarcinoma of the prostate. Its efficacy in reducing cancer-specific mortality in patients who have a survival expectancy of less than 15 years (older than 65 years) and moderately or well-differentiated adenocarcinoma of the prostate is less clear. Radical prostatectomy, with or without adjuvant hormonal therapy, decreases metastatic rates in men with a life expectancy of 10 years or more (age 75 years or younger) irrespective of tumor grade and, thus, should improve the QOL expectancy in these men. Nevertheless, between 20% and 60% of patients undergoing radical prostatectomy have biochemical recurrence, as defined by a detectable PSA, at 10 years of follow-up. This is worrisome and may portend clinical failure with longer follow-up.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1995

Wheezing during induction of general anesthesia in patients with and without asthma. A randomized, blinded trial.

BACKGROUND: Patients with asthma who require general anesthesia and tracheal intubation are at increased risk for the development of bronchospasm during induction. The incidence of wheezing during induction with different intravenously administered agents is unknown. A randomized, double-blinded prospective study was undertaken to evaluate the incidence of wheezing in asymptomatic asthmatic and nonasthmatic patients receiving three commonly used intravenous anesthetic agents for induction of anesthesia. METHODS: Fifty-nine asymptomatic asthmatic and 96 nonasthmatic patients of ASA physical status 1 and 2 were studied. All patients received 1.5 micrograms/kg fentanyl, oxygen, followed by either 5 mg/kg thiopental or thiamylal, 1.75 mg/kg methohexital or 2.5 mg/kg propofol, 1.5 mg/kg succinylcholine, tracheal intubation, and inhalational anesthesia. Wheezing was assessed by an independent blinded observer, auscultating the lungs at 2 and 5 min postintubation. Data were analyzed by Pearson's chi-squared, Fisher's exact test, and multiple logistic regression with significance set at P < 0.05. RESULTS: Both asthmatic and nonasthmatic patients who received a thiobarbiturate for induction had a greater incidence of wheezing than did patients receiving propofol. In asthmatic patients, 45% (23, 67) (mean and 95% confidence interval) who received a thiobarbiturate, 26% (8, 44) who received an oxybarbiturate, and none (0, 17) who received propofol wheezed after intubation. In nonasthmatic patients, 16% (3, 28) who received thiobarbiturate and 3% (0, 9) who received propofol wheezed. CONCLUSIONS: This study suggests that propofol should be considered for induction of anesthesia in patients, particularly those with asthma, who require timely intubation.

Adolescent↗