Search PubMed⌕ Search

Biomedical subjects

J Douglas

Publications and source records attributed to J Douglas.

At least 37 records · Page 2Linked to original sources
PubMed2000

In vitro selection of lentivirus vector-transduced human CD34+ cells.

Human CD34(+) cells with in vivo repopulating potential hold much promise as a target for corrective gene transfer for numerous hematopoietic disorders. However, the efficient introduction of exogenous genes into this small, quiescent population of cells continues to present a significant challenge. To circumvent the need for high initial transduction efficiency of human hematopoietic cells, we investigated a dominant selection strategy using a variant of the DHFR gene (DHFR(L22Y)). For this purpose, we constructed a lentivirus-based bicistronic vector expressing EGFP and DHFR(L22Y). Here we demonstrate efficient in vitro selection and enrichment of lentivirus vector-transduced human CD34(+) hematopoietic cells from fetal liver, umbilical cord blood, bone marrow, and peripheral blood after cytokine mobilization. Growth of transduced human CD34(+) cells in semisolid culture under selective pressure resulted in enrichment of transduced progenitor cells to 99.5% (n = 14). Selection for DHFR(L22Y)(+) cells after expansion of transduced progenitors in liquid culture resulted in a 7- to 13-fold increase in the percentage of marked cells. Thus we have shown that transduced human hematopoietic cells may be effectively enriched in vitro by dominant selection, suggesting that development of such strategies holds promise for future in vivo application.

Antigens, CD34↗
PubMed2000

Neurokinin 1 receptor distribution in cholinergic neurons and targets of substance P terminals in the rat nucleus accumbens.

Substance P (SP) is the major endogenous ligand for neurokinin 1 (NK1) receptors and, together with acetylcholine, has an important role in motivated behaviors involving the limbic shell and motor core of the nucleus accumbens (NAc). To determine the functional sites for SP activation of NK-1 receptors and potential interactions with cholinergic neurons in these regions, the authors examined the electron microscopic immunocytochemical localization either of antisera against the NK1 receptor or of the NK1 receptor and either 1) SP or 2) the vesicular acetylcholine transporter (VAchT) in rat NAc. In both the NAc shell and core, NK1 receptor labeling was localized mainly to somatic and dendritic plasma membranes and nearby endosomal organelles in aspiny neurons. In sections through the ventromedial shell that were processed for NK1/SP labeling, 46% of the NK1-immunoreactive dendrites (n = 603 dendrites) showed symmetric or appositional contacts with SP-containing terminals. These terminals and several others that formed symmetric synapses also occasionally were immunoreactive for NK1 receptors. Analysis of the shell region for NK1/VAchT labeling showed that 61% of the total immunoreactive dendrites (n = 534 dendrites) contained NK1 receptors without VAchT, 29% contained both products, and 10% contained VAchT only. Many of the labeled somata and dendrites also received synaptic contact from VAchT-containing terminals. These findings suggest that, in the NAc, NK1 receptors are recycled through endosomal compartments and play a role in modulating mainly the postsynaptic responses, but also the presynaptic release, of SP and/or inhibitory neurotransmitters onto aspiny interneurons, some of which are cholinergic.

Animals↗
PubMed2000

Cocaine misuse treatment in England.

Three methods were used to identify the treatments given to cocaine misusers in England, and to make a preliminary assessment of effectiveness. First, a postal survey of all known drug misuse treatment services ascertained approximate numbers of cocaine misusers presenting and receiving a specified range of treatments. Secondly, staff at selected services were interviewed regarding treatment policies, and asked to subjectively rate short-term and long-term effectiveness. Thirdly, a cohort of individuals in treatment were studied prospectively to assess changes in drug usage and associated problems. Fifty percent of services responded to the survey, but there was known to be significant duplication in service listings and it is considered that a representative pattern of clinical activity has been detected. Approximately half those services had recently treated cocaine misusers, mainly using counselling, residential rehabilitation, and pharmacological treatments, in which 32 different medications were identified. Acupuncture was prominent in a minority of services. Staff interviews suggested several principles in managing cocaine misusers, while all treatments were rated as being more effective in short-term relief of withdrawal features than in enabling longer-term abstinence. The treatment cohort were mostly in residential rehabilitation, and marked reductions in drug use and related clinical and social problems were demonstrated.

Journal Article↗
PubMed2000

Superior transduction of mouse hematopoietic stem cells with 10A1 and VSV-G pseudotyped retrovirus vectors.

The inefficient transduction of human hematopoietic stem cells (HSC) with amphotropic retroviral vectors has been an obstacle to gene therapy for hematopoietic diseases. We have previously reported low levels of amphotropic retrovirus receptor (Pit-2) mRNA and higher levels of gibbon ape leukemia virus (GALV) or 10A1 retrovirus receptor (Pit-1) mRNA in mouse and human HSC. The vesicular stomatitis virus (VSV-G) uses an abundant membrane phospholipid as a receptor. We hypothesized that transduction of HSC requires relatively high levels of retrovirus receptor molecules. Because mouse HSC can be efficiently transduced by ecotropic virus through the abundant ecotropic receptor, the mouse is an ideal model to compare receptor levels and transduction. We have developed a cotransduction assay where ecotropic retrovirus transduction is a positive internal control for downstream steps in retrovirus transduction. A comparison of mouse HSC transduction with amphotropic, 10A1, and VSV-G envelopes showed that the level of amphotropic and 10A1 receptor mRNA in HSC correlated with the frequency of transduction. Transduction with VSV-G vectors was similar to that with 10A1 vectors. We conclude that the level of retrovirus receptor on HSC is critical for HSC transduction and that GALV or VSV-G vectors would be better for human HSC transduction.

Animals↗
PubMed2000

Managed care, time pressure, and physician job satisfaction: results from the physician worklife study.

OBJECTIVE: To assess the association between HMO practice, time pressure, and physician job satisfaction. DESIGN: National random stratified sample of 5,704 primary care and specialty physicians in the United States. Surveys contained 150 items reflecting 10 facets (components) of satisfaction in addition to global satisfaction with current job, one's career and one's specialty. Linear regression-modeled satisfaction (on 1-5 scale) as a function of specialty, practice setting (solo, small group, large group, academic, or HMO), gender, ethnicity, full-time versus part-time status, and time pressure during office visits. "HMO physicians" (9% of total) were those in group or staff model HMOs with > 50% of patients capitated or in managed care. RESULTS: Of the 2,326 respondents, 735 (32%) were female, 607 (26%) were minority (adjusted response rate 52%). HMO physicians reported significantly higher satisfaction with autonomy and administrative issues when compared with other practice types (moderate to large effect sizes). However, physicians in many other practice settings averaged higher satisfaction than HMO physicians with resources and relationships with staff and community (small to moderate effect sizes). Small and large group practice and academic physicians had higher global job satisfaction scores than HMO physicians (P <.05), and private practice physicians had quarter to half the odds of HMO physicians of intending to leave their current practice within 2 years (P <.05). Time pressure detracted from satisfaction in 7 of 10 satisfaction facets (P <.05) and from job, career, and specialty satisfaction (P <.01). Time allotted for new patients in HMOs (31 min) was less than that allotted in solo (39 min) and academic practices (44 min), while 83% of family physicians in HMOs felt they needed more time than allotted for new patients versus 54% of family physicians in small group practices (P <.05 after Bonferroni's correction). CONCLUSIONS: HMO physicians are generally less satisfied with their jobs and more likely to intend to leave their practices than physicians in many other practice settings. Our data suggest that HMO physicians' satisfaction with staff, community, resources, and the duration of new patient visits should be assessed and optimized. Whether providing more time for patient encounters would improve job satisfaction in HMOs or other practice settings remains to be determined.

Adult↗
PubMed2000

Preserving renal function in adults with hypertension and diabetes: a consensus approach. National Kidney Foundation Hypertension and Diabetes Executive Committees Working Group.

Over 11 million Americans have both diabetes and hypertension-comorbid diseases that strongly predispose people to both renal as well as cardiovascular (CV) injury. Hypertension substantially contributes to CV morbidity and mortality in people with diabetes. Diabetes is the most common cause of end-stage renal disease in the United States. Furthermore, hypertension and diabetes are particularly prevalent in certain populations, such as African-Americans and Native Americans. Since the 1994 Working Group Report on Hypertension and Diabetes, a large body of clinical trial data has affirmed the original blood pressure goal of less than 130/85 mmHg recommended to preserve renal function and reduce CV events in people with hypertension and diabetes. Data that are more recent have emerged, however, to support an even lower diastolic blood pressure goal, ie, 80 mmHg, in order to optimally preserve renal function and reduce CV events in people with diabetic nephropathy. A review of clinical trials indicates that more than 65% of people with diabetes and hypertension will require two or more different antihypertensive medications to achieve the new suggested target blood pressure of 130/80 mmHg. The purpose of this report is to update the previous recommendations with a focus on level of blood pressure control, proteinuria reduction, and therapeutic approaches to achieve these goals. We provide an evidence-based approach, integrating data from the major clinical trials that were designed as randomized prospective, long-term studies that had as a primary endpoint either progression of diabetic nephropathy or reduction in CV events. This report also addresses socioeconomic and cultural barriers that hinder achievement of blood pressure goals. Lastly, the report discusses approaches to resolve cultural barriers, both physician- and patient-derived, that interfere with achievement of lower blood pressure goals.

Adult↗
PubMed2000

Multicenter, randomized, controlled trial of delayed pushing for nulliparous women in the second stage of labor with continuous epidural analgesia. The PEOPLE (Pushing Early or Pushing Late with Epidural) Study Group.

OBJECTIVE: This study was undertaken to determine whether a policy of delayed pushing for nulliparous women with continuous-infusion epidural analgesia reduces the risk of difficult delivery (cesarean delivery, operative delivery from a midpelvic position, low-pelvic procedures with rotation >45 degrees ). STUDY DESIGN: In this multicenter, randomized, controlled trial women in the delayed pushing group (n = 936) were advised to wait > or =2 hours after full dilatation before commencement of pushing. Women in the early pushing group (n = 926) were advised to commence pushing as soon as they had been randomly assigned. RESULTS: Difficult delivery was reduced with delayed pushing (relative risk, 0.79; 95% confidence interval, 0.66-0.95). The greatest effect was on midpelvic procedures (relative risk, 0.72; 95% confidence interval, 0.55-0.93). Although there was little evidence for an effect on low-pelvic procedures, spontaneous delivery was more frequent among women who practiced delayed pushing (relative risk, 1.09; 95% confidence interval, 1.00-1.18). Abnormal umbilical cord blood pH (<7.15 venous value or <7.10 arterial value) was more frequent in the delayed pushing group (relative risk, 2.45, 95% confidence interval, 1.35-4. 43). However, scores for a summary indicator, the Neonatal Morbidity Index, were similarly distributed in the 2 groups. CONCLUSION: Delayed pushing is an effective strategy to reduce difficult deliveries among nulliparous women.

Analgesia, Epidural↗
PubMed2000

Medical supervision of sport diving in Scotland: reassessing the need for routine medical examinations.

BACKGROUND: The value of diving medicals in preventing incidents is uncertain and there has been only limited evaluation of the fitness to dive guidelines in a sport diving population. OBJECTIVE: To examine the need for routine diving medical examinations in the Scottish Sub-Aqua Club (SSAC) between 1991 and 1998. METHODS: A medical examination of all SSAC divers is performed at entry and then every one to five years based on their age and medical condition This information was analysed in terms of questionnaire findings and examination abnormalities. RESULTS: There were 2,962 medical forms available for analysis. Examination abnormalities were found in 174 subjects (5.9% of the population), with obesity affecting 75 subjects (2.5%). There was a linear increase in mean body mass index (r2 = 0.92), and a significant difference between 1991 and 1998 (mean (SD) of 24.1 (3.07) and 25.02 (3.4) respectively, p = 0.002) which was not related to age or sex distribution. There was also a significant increase in the prevalence of smokers (chi2 = 4.02, p = 0.045). The most common specialist referral was for evaluation of asthma, with hypertension and obesity as the next most common reasons. Most subjects were allowed to dive, with only 43 (25%) being failed outright. Overall, no examination abnormality alone caused a subject to be classified unfit to dive, and referrals were prompted by the answers in the questionnaire. CONCLUSIONS: No significant unexpected abnormalities were found on clinical examination in this population of sport divers. Conditions that prevented subjects from diving were detected by the questionnaire, and this prompted referral for further assessment by the medical advisors. Routine medical examinations were of little value.

Chi-Square Distribution↗
PubMed2000

Auditory integration training for children with autism: no behavioral benefits detected.

Auditory integration training and a control treatment were provided for 16 children with autism in a crossover experimental design. Measures, blind to treatment order, included parent and teacher ratings of behavior, direct observational recordings, IQ, language, and social/adaptive tests. Significant differences tended to show that the control condition was superior on parent-rated measures of hyperactivity and on direct observational measures of ear-occlusion. No differences were detected on teacher-rated measures. Children's IQs and language comprehension did not increase, but adaptive/social behavior scores and expressive language quotients decreased. The majority of parents (56%) were unable to report in retrospect when their child had received auditory integration training. No individual child was identified as benefiting clinically or educationally from the treatment.

Acoustic Stimulation↗
PubMed2000

The work lives of women physicians results from the physician work life study. The SGIM Career Satisfaction Study Group.

OBJECTIVE: To describe gender differences in job satisfaction, work life issues, and burnout of U.S. physicians. DESIGN/PARTICIPANTS: The Physician Work life Study, a nationally representative random stratified sample of 5,704 physicians in primary and specialty nonsurgical care (N = 2,326 respondents; 32% female, adjusted response rate = 52%). Survey contained 150 items assessing career satisfaction and multiple aspects of work life. MEASUREMENTS AND MAIN RESULTS: Odds of being satisfied with facets of work life and odds of reporting burnout were modeled with survey-weighted logistic regression controlling for demographic variables and practice characteristics. Multiple linear regression was performed to model dependent variables of global, career, and specialty satisfaction with independent variables of income, time pressure, and items measuring control over medical and workplace issues. Compared with male physicians, female physicians were more likely to report satisfaction with their specialty and with patient and colleague relationships (P <.05), but less likely to be satisfied with autonomy, relationships with community, pay, and resources (P <.05). Female physicians reported more female patients and more patients with complex psychosocial problems, but the same numbers of complex medical patients, compared with their male colleagues. Time pressure in ambulatory settings was greater for women, who on average reported needing 36% more time than allotted to provide quality care for new patients or consultations, compared with 21% more time needed by men (P <.01). Female physicians reported significantly less work control than male physicians regarding day-to-day aspects of practice including volume of patient load, selecting physicians for referrals, and details of office scheduling (P <.01). When controlling for multiple factors, mean income for women was approximately $22,000 less than that of men. Women had 1.6 times the odds of reporting burnout compared with men (P <.05), with the odds of burnout by women increasing by 12% to 15% for each additional 5 hours worked per week over 40 hours (P <.05). Lack of workplace control predicted burnout in women but not in men. For those women with young children, odds of burnout were 40% less when support of colleagues, spouse, or significant other for balancing work and home issues was present. CONCLUSIONS: Gender differences exist in both the experience of and satisfaction with medical practice. Addressing these gender differences will optimize the participation of female physicians within the medical workforce.

Adult↗
PubMed1999

Per-contact risk of human immunodeficiency virus transmission between male sexual partners.

The risk of human immunodeficiency virus (HIV) transmission from various types of homosexual contact, including oral sex, is of biologic, epidemiologic, and public health importance. The per-contact risk of acquiring HIV infection from specific acts was estimated in a prospective cohort study of 2,189 high-risk homosexual and bisexual men, conducted in San Francisco, California; Denver, Colorado; and Chicago, Illinois, in 1992-1994. During 2,633 person-years of follow-up, 60 seroconversions were observed. The estimated per-contact risk of acquiring HIV from unprotected receptive anal intercourse (URA) was 0.82 percent (95% confidence interval: 0.24, 2.76 percent) when the partner was known to be HIV+ and 0.27 percent (95% confidence interval: 0.06, 0.49 percent) when partners of unknown serostatus were included. There was heterogeneity in per-contact risk, with nine seroconversions occurring after only one or two episodes of URA. The per-contact risk associated with unprotected insertive anal and receptive oral sex with HIV-positive or unknown serostatus partners was 0.06 and 0.04 percent, respectively. URA accounted for only 15 percent of all reported sexual activity by seroconverters. As lower-risk practices become more common, they may play a larger role in propagating the epidemic and should also be addressed by interventions targeting high-risk homosexual and bisexual men.

Cohort Studies↗
PubMed1999

Efficient transduction of human lymphocytes and CD34+ cells via human immunodeficiency virus-based gene transfer vectors.

The development of gene transfer systems for the efficient transduction of human primary cells including lymphocytes and CD34+ cells is a significant step in the advancement of gene therapy and cell marking protocols. Efficient gene transfer systems also represent useful tools for basic research. Here we show that human primary lymphocytes and CD34+ cells can be efficiently transduced using a VSV-G pseudotyped HIV-1-based gene transfer system. The enhanced green fluorescent protein (EGFP) was chosen as the marker transgene, because it can be easily visualized and quantitated using fluorescence microscopy and flow cytometry, thus eliminating the need for selection or PCR to score transduction. Vectors produced with this system did not generate replication-competent retroviruses (RCRs) and efficiently transduced human cell lines (40-90%), PBMCs (60%), mobilized CD34+ cells (39%), and CD34+ cells from umbilical cord blood (60%) as measured by flow cytometry. Cells treated with AZT prior to infection did not express EGFP, ruling out passive protein or plasmid DNA transfer. This was further confirmed in methylcellulose cultures, where expression in myeloid and erythroid colonies was maintained for at least 3 weeks. In addition, this HIV-based vector was able to efficiently transduce freshly isolated, not-prestimulated CD34+ cells (70% EGFP positive) in serum-free medium. Under these same conditions, a Moloney murine leukemia virus-based vector failed to transduce not-prestimulated CD34+ cells. These characteristics make this gene transfer system an excellent choice for both basic science and possible gene therapy applications.

Antigens, CD34↗
PubMed1999

Reliable and sensitive detection of premature termination mutations using a protein truncation test designed to overcome problems of nonsense-mediated mRNA instability.

The protein truncation test (PTT) is a mutation-detection method used to scan for premature termination (nonsense) mutations. PCR amplification of the DNA or mRNA source material is performed using forward primers containing a T7-promoter sequence and translation initiation signals such that the resultant products can be transcribed and translated in vitro to identify the smaller truncated protein products. mRNA is commonly used as the source material, but success of the PTT and other RNA-based mutation detection methods can be severely compromised by nonsense mutation-induced mRNA decay, a well-documented process that is often overlooked in mutation detection strategies. In this study, we develop an RNA-based PTT that overcomes the problem of mRNA decay by preincubating cells with cycloheximide to stabilise the mutant mRNA. The effectiveness of this method for mutation detection in abundant mRNAs was demonstrated in osteogenesis imperfecta fibroblasts by the protection of type I collagen (COL1A1) mRNA containing nonsense mutations that normally resulted in mutant mRNA degradation. Stabilisation of mutant mismatch repair gene (MLH1) mRNA was also observed in transformed lymphocytes from patients with hereditary nonpolyposis colorectal cancer (HNPCC). Importantly, our strategy also stabilised very low-level (or illegitimate) nonsense-containing transcripts in lymphoblasts from patients with Bethlem myopathy (COL6A1), familial adenomatous polyposis (APC), and breast cancer (BRCA1). The greatly increased sensitivity and reliability of this RT-PCR/PTT protocol has broad applicability to the many genetic diseases in which only blood-derived cells may be readily available for analysis.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Preoperative dextrose does not affect spinal-induced hypotension in elective Cesarean section.

PURPOSE: To determine if preoperative intravenous dextrose affects the incidence and ease of treatment of spinal-induced hypotension in parturients having elective Cesarean section under spinal anesthesia. METHODS: In this prospective, double-blind study, following informed consent, 119 ASA I, II parturients for elective Cesarean section were randomized to receive intravenously either dextrose 5% in normal saline (Group D) or normal saline (Group NS) at 125 ml x hr(-1) for two hours prior to delivery. Following a bolus of 15 ml x kg(-1) normal saline iv, spinal anesthesia was induced with hyperbaric bupivacaine 0.75%, fentanyl and morphine. Hypotension (systolic blood pressure <100 mm Hg or >20% decrease) was treated with fluids and/or vasopressor. DATA COLLECTED: demographics, blood glucose concentrations (fasting, time of spinal, delivery), blood pressure (baseline, one minute intervals from spinal to delivery), neonatal Apgar scores, umbilical blood gas analyses, glucose and lactate concentrations. RESULTS: There was no difference between the two groups in the rate of hypotension (P = 0.272). All parturients who experienced hypotension received fluids, and there was also no difference between the groups in vasopressor requirement [mean dose of ephedrine: Group D = 21.6 mg (95% CI 15.1-28.2), Group NS = 16 mg (95% CI 12.0-20.5)]. CONCLUSION: The routine administration of dextrose 5% at a rate of 5.22 g x hr(-1) preoperatively does not affect the hypotension rate, or make it easier to treat.

Adult↗
PubMed1999

Refining the measurement of physician job satisfaction: results from the Physician Worklife Survey. SGIM Career Satisfaction Study Group. Society of General Internal Medicine.

BACKGROUND: Physician job satisfaction has been linked to various patient care and health system outcomes. A survey instrument that concisely measures physicians' satisfaction with various job facets can help diverse stake-holders to better understand and manage these outcomes. OBJECTIVE: To document the development and validation of a multidimensional physician job satisfaction measure and separate global satisfaction measures. DESIGN: Self-administered questionnaire: Physician Worklife Survey (PWS). SUBJECTS: A pilot study employed a national American Medical Association Masterfile sample of US primary care physicians and random samples from four states. Responses (n = 835; 55% return rate) were randomly assigned to developmental (n = 560) or cross-validation (n = 275) samples. A national sample (n = 2,325; 52% response rate) of physicians was used in a subsequent validation study. RESULTS: A 38-item, 10-facet satisfaction measure resulting from factor and reliability analyses of 70 pilot items was further reduced to 36 items. Reliabilities of the 10 facets ranged from .65 to .77. Three scales measuring global job, career, and specialty satisfaction were also constructed with reliabilities from .84 to .88. Results supported face, content, convergent, and discriminant validity of the measures. CONCLUSIONS: Physician job satisfaction is a complex phenomenon that can be measured using the PWS.

Adult↗