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Biomedical subjects

S M Hall

Publications and source records attributed to S M Hall.

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

Prenatal origins of human intrapulmonary arteries: formation and smooth muscle maturation.

Recent studies on the morphogenesis of the pulmonary arteries have focused on nonhuman species such as the chick and the mouse. Using immunohistochemical techniques, we have studied 16 lungs from human embryos and fetuses from 28 d of gestation to newborn, using serial sections stained with a panel of antibodies specific for endothelium, smooth muscle, and extracellular matrix proteins. Cell replication was also assessed. Serial reconstruction showed a continuity of circulation between the heart and the capillary plexus from at least 38 d of gestation. The intrapulmonary arteries appeared to be derived from a continuous expansion of the primary capillary plexus that is from within the mesenchyme, by vasculogenesis. The arteries formed by continuous coalescence of endothelial tubes alongside the newly formed airway. Findings were consistent with the pulmonary arterial smooth muscle cells being derived from three sites in a temporally distinct sequence: the earliest from the bronchial smooth muscle, later from the mesenchyme surrounding the arteries, and last from the endothelial cells. Despite their different origins, all smooth muscle cells followed the same sequence of expression of smooth muscle-specific cytoskeletal proteins with increasing age. The order of appearance of these maturing proteins was from the subendothelial cells outward across the vessel wall and from hilum to periphery. The airways would seem to act as a template for pulmonary artery development. This study provides a framework for studying the signaling mechanisms controlling the various aspects of lung development.

Actins↗
PubMed2000

Development of major depression after treatment for smoking cessation.

OBJECTIVE: Case studies suggest cigarette abstinence may precipitate a major depressive episode. This study examined the incidence and predictors of major depression in the 12 months after treatment for smoking cessation. METHOD: Participants (N=304, 172 women) were recruited from two trials of smoking cessation. Both trials provided psychological group intervention, but one group received treatment with nicotine gum and the other was given nortriptyline or placebo. The incidence of major depressive episodes was identified by the Inventory to Diagnose Depression, which was administered at follow-up assessments. RESULTS: The 12-month incidence of major depression after treatment for smoking cessation was 14.1% (N=43). Multiple logistic regression analyses indicated that history of depression, baseline Beck Depression Inventory score, college education, and age at smoking initiation were significant predictors of major depression after treatment. Abstinence at the end of treatment did not significantly predict major depression. CONCLUSIONS: Patients who achieved abstinence from smoking showed a risk of developing depressive episodes similar to those who failed to achieve abstinence. As expected, patients who had a history of depression were more likely to experience depressive episodes after treatment for smoking cessation. The 12-month incidence of major depression in this study group was higher than that observed in the general population, but reasons for the elevation were not clear.

Adult↗
PubMed1999

The biology of chronically denervated Schwann cells.

This paper is divided into two sections, both concerned with the effects of chronic denervation on Schwann cells. The first group of experiments explore the proposal that lengthy denervation produces changes in Schwann cells in vivo that compromise axonal regeneration. The second group of experiments compare the molecular phenotypes of acutely and chronically denervated Schwann cells in vitro, and examine their responses to an exogenously applied neuregulin.

Animals↗
PubMed1999

Reye's syndrome.

Explore the source record for details and available documents.

Adolescent↗
PubMed1999

How do Jains get toxoplasma infection?

Toxoplasma infection is as prevalent among Jains as among other religious groups in the same area. Jain laws mean that exposure to Toxoplasma gondii via well known routes of infection is unlikely; drinking water may be the vehicle of infection.

Animals↗
PubMed1999

Contingency contracting with monetary reinforcers for abstinence from multiple drugs in a methadone program.

Positive monetary contingencies for treating opioid dependence complicated by other drug use were examined. Participants (N = 102) entered 6-month methadone transition treatment (MTT) and were randomized into experimental conditions: 51 entered MTT with contingency contracts using monetary reinforcers and targeting abstinence from illicit drug and alcohol use, and 51 entered MTT without contingency contracts targeting abstinence. Outcomes were evaluated by random urinalysis and breath analysis. After 4 months of treatment, individuals in the contingency condition had longer periods of continuous abstinence (p<.005) and more drug-free tests overall (p<.04). Effects were limited, however, to the contracting period. The authors conclude that contingency contracting using monetary reinforcers may be a useful adjunct for achieving abstinence from multiple drugs of abuse during MTT.

Adolescent↗
PubMed1999

Psychological interventions: state of the art.

The usefulness of psychological interventions in smoking cessation is well established. Ongoing efforts are aimed at establishing interventions for specific diagnostic groups, developing interventions that are targeted at smokers who do not seek treatment, and combining psychological and pharmacological treatment. There is emerging evidence that useful treatments have been developed for smokers with a depression history, and that expert system interventions based upon a stage model can be useful in changing the smoking behavior of smokers who are not yet ready to quit. Psychological interventions add to the efficacy of nicotine replacement therapy, but whether they add to the efficacy of other pharmacotherapies is not known. There is a need to determine whether psychological interventions are useful for diagnostic groups other than depressive disorder, and if so, whether they need be specific for that group. Additional research is needed on interventions for smokers who are not ready to quit, both in developing new techniques, and determining the need and usefulness of adaptations of those in existence to specific populations.

Adaptation, Psychological↗
PubMed1999

A cost-effectiveness and cost-benefit analysis of contingency contracting-enhanced methadone detoxification treatment.

We examined treatment costs in an ongoing study in which 102 opioid-addicted patients had been randomly assigned to either 180-day methadone detoxification or the same treatment enhanced with contingency contracting. In the latter condition, study participants received regular reinforcers contingent on negative urine toxicology screens and breath analyses for a range of drugs and alcohol. Both conditions involved psychosocial treatment, and all participants were stabilized to a daily methadone dose of approximately 80 mg during the first 4 months, followed by a 2-month taper. Individuals participating in the enhanced condition were more likely to provide continuously drug-free urine samples and alcohol-free breath samples during the final month of treatment than were participants in the control condition. Cost of treatment was calculated individually for each participant based on actual services received. First, unit cost for each service was determined, including adjusted staff salaries for direct treatment and opportunity cost of facilities utilized during service delivery. Next, we valued each patient's use of services during the first 120 days of the study and then added the cost of methadone, laboratory work, and contingent reinforcers. A subsample (n = 45) also provided data on health care utilization during treatment, which we valued using standard Medicare unit costs. The marginal cost of enhancing the standard treatment with contingency contracting was approximately 8%. An incremental cost of $17.27 produced an additional 1% increase in the number of participants providing continuously substance-free urine and breath samples during month 4 of the study. For every additional dollar spent on treatment, a $4.87 health care cost offset was realized; however, this difference was statistically insignificant due to extreme variances and small subsample size.

Cost-Benefit Analysis↗
PubMed1999

Detection of illicit opioid and cocaine use in methadone maintenance treatment.

Urine toxicology is the gold standard for estimating the prevalence of illicit drug use in methadone maintenance treatment (MMT). The frequency of urine testing may be crucial for establishing accurate use rates. Infrequent testing may lead programs to undercount active drug users and to target interventions too narrowly. This study compared results from frequent testing (twice per week) versus less frequent testing of 166 patients at four MMT programs. As part of a research study, all patients were tested by research staff for opioid and cocaine use twice per week on a fixed schedule for 10 weeks. During the same period, the four MMT programs tested the patients according to their standard protocols, approximately weekly (one program) or every 3-4 weeks (three programs). The research tests identified approximately 50% more illicit opioid users and 70% more cocaine users than the less frequent program tests. Patients who were drug positive according to the research tests but drug negative according to the program tests tended to be infrequent users. The data suggest that standard urine testing practices in MMT programs may result in underestimates of the prevalence of opioid and cocaine use. More frequent testing, even for time-limited periods, should produce more accurate depictions of drug use prevalence and help indicate the direction of interventions.

Adult↗
PubMed1998

Factors associated with lapses to heroin use during methadone maintenance.

This prospective, observational study investigated factors predicting a lapse to heroin use in 74 heroin-abstinent methadone maintenance patients. After baseline data collection, participants were assessed twice per week for 7 weeks and again at 6 months after baseline. Proportional hazards regression and logistic regression were used to investigate the effects of study predictors on heroin use. A goal of absolute heroin abstinence consistently predicted a lower risk of a lapse, whereas marijuana use was associated with a greater risk. Stress variables were not predictive. The abstinence goal and stress results were consistent with the authors' previous studies of other drug treatment samples. This line of research suggests that factors influencing lapses are similar across drug treatment populations and the role of stress in precipitating relapse remains unresolved.

Adult↗
PubMed1998

Cortisol and response to dexamethasone as predictors of withdrawal distress and abstinence success in smokers.

BACKGROUND: Glucocorticoids have been linked to self-administration of a wide range of drugs in animals and are increased endogenously by chronic nicotine intake. Corticosteroids have also been shown to regulate nicotine receptor sensitivity and to be involved in behavioral sensitization to nicotine. METHODS: Cortisol levels and cortisol suppression in response to dexamethasone were measured in a sample of smokers participating in a smoking cessation treatment trial. RESULTS: Cortisol levels dropped significantly during the early quitting process (2 weeks post-quit) and returned to a level below baseline 1 month post-quit. The magnitude of the initial drop in cortisol was strongly related to post-quit distress and marginally predictive of abstinence. Neither baseline nor post-quit changes in percent cortisol suppression after dexamethasone were related to abstinence success or withdrawal distress. CONCLUSIONS: Withdrawal from cigarette smoking is marked by a reduction in cortisol levels that appears to be related to the degree of distress experienced during the early quitting period. Further work is needed to determine whether withdrawal-related cortisol changes or distress are predictive of abstinence success.

Adult↗
PubMed1998

An acute dose of nicotine enhances cue-induced cocaine craving.

The present study examined whether the active component in tobacco, nicotine, can modulate cocaine craving in patients with a history of smoking crack cocaine when exposed to crack cocaine related environmental cues. Twenty patients, all cigarette smokers, were randomly assigned to nicotine (two 22 mg transdermal patches) or placebo in a single-dose, placebo-controlled, crossover, double-blind study. Craving and anxiety were measured before and after cocaine cues with visual analog scales for desire to use cocaine and mood. Skin conductance and skin temperature were recorded before and during cocaine cues. Following exposure to cocaine cues, all patients reported an increase in cocaine craving and anxiety relative to the pre-cue measures. Cue exposure also produced an increase in skin conductance and decrease in skin temperature. The cue-induced increase in cocaine craving was strongly enhanced by nicotine, while the increase in anxiety was slightly augmented. Cue-induced skin conductance and temperature responses were unaffected by nicotine. These findings show that cue-induced cocaine craving is enhanced by nicotine. This occurred in the absence of any tobacco smoking-related cues, suggesting that nicotine may have direct psychopharmacological effects on conditioned cocaine craving.

Adult↗
PubMed1998

Nortriptyline and cognitive-behavioral therapy in the treatment of cigarette smoking.

BACKGROUND: A history of major depressive disorder (MDD) predicts failure to quit smoking. We determined the effect of nortriptyline hydrochloride and cognitive-behavioral therapy on smoking treatment outcome in smokers with a history of MDD. The study also addressed the effects of diagnosis and treatment condition on dysphoria after quitting smoking and the effects of dysphoria on abstinence. METHODS: This was a 2 (nortriptyline vs placebo) x 2 (cognitive-behavioral therapy vs control) x 2 (history of MDD vs no history) randomized trial. The participants were 199 cigarette smokers. The outcome measures were biologically verified abstinence from cigarettes at weeks 12, 24, 38, and 64. Mood, withdrawal, and depression were measured at 3, 5, and 8 days after the smoking quit date. RESULTS: Nortriptyline produced higher abstinence rates than placebo, independent of depression history. Cognitive-behavioral therapy was more effective for participants with a history of depression. Nortriptyline alleviated a negative affect occurring after smoking cessation. Increases in the level of negative affect from baseline to 3 days after the smoking quit date predicted abstinence at later assessments for MDD history-negative smokers. There was also a sex-by-depression history interaction; MDD history-positive women were less likely to be abstinent than MDD history-negative women, but depression history did not predict abstinence for men. CONCLUSIONS: Nortriptyline is a promising adjunct for smoking cessation. Smokers with a history of depression are aided by more intensive psychosocial treatments. Mood and diagnosis interact to predict relapse. Increases in negative affect after quitting smoking are attenuated by nortriptyline.

Adult↗
PubMed1998

Staying in control: women's experiences of labour in water.

AIM: To examine women's attempts at control during labour in water. DESIGN: An exploratory design consisting of tape-recorded, in-depth interviews using the grounded theory approach. SETTING: A medium sized town in the south of England. The data were collected in the maternity unit of a local general hospital set in a semi-rural location. PARTICIPANTS: Nine women who had chosen to spend their labour process in water. The participants selected had experienced a normal pregnancy and given birth to a healthy baby at term. FINDINGS: Labour in water was seen by all but one of the participants as beneficial, particularly as they felt that this gave them more control over the process. They valued their own involvement in determining the outcome of their care. The support of the midwife in making decisions was seen as necessary to remain in control. CONCLUSIONS: Labour in water was a positive experience for this group of healthy women. The feeling of freedom to make decisions, however, was balanced with a wish for the support of the midwife.

Attitude to Health↗
PubMed1998

A morphological study of Schwann cells and axonal regeneration in chronically transected human peripheral nerves.

Relatively little is known about the effects of chronic transection on human peripheral nerves. In this study intraoperative biopsies were obtained from proximal and distal nerve stumps and intervening neuromas resected before peripheral nerve reconstruction. Biopsies were collected from ten patients following differing types of nerve injury, with delays to repair ranging from 8 to 53 months. Nerves were examined by light and electron microscopy. In general, reinnervation was poor, although even following the most severe injuries, all of the distal stumps contained some regrowing axons, which were always associated with Schwann cells. Denervated Schwann cells, arranged in typical bands of Büngner were consistently present in each distal stump. Our findings confirm that the morphology of chronically denervated human peripheral nerves is essentially similar to that described in experimental models.

Adolescent↗
PubMed1998

Superior efficacy of cognitive-behavioral therapy for urban crack cocaine abusers: main and matching effects.

This study evaluated the efficacy of cognitive-behavioral therapy (CBT) and 12-step facilitation (12SF) in treating cocaine abuse. Participants (N = 128) were randomly assigned to treatment conditions and assessed at baseline and at Weeks 4, 8, 12, and 26. Treatment lasted for 12 weeks. It was hypothesized that participants treated with CBT would be significantly more likely to achieve abstinence from cocaine than participants treated with 12SF. A series of patient-treatment matching hypotheses was also proposed. Across 2 different outcome variables, it was found that participants in CBT were significantly more likely to achieve abstinence than participants in 12SF. In addition, some support for matching hypotheses was found, suggesting that both psychotherapies may be differentially effective for identified subgroups of persons that abuse cocaine.

Adult↗
PubMed1998

The British Paediatric Surveillance Unit--a pioneering method for investigating the less common disorders of childhood. Report of a seminar held in June 1995.

The British Paediatric Surveillance Unit (BPSU) of the Royal College of Paediatrics and Child Health is an 'active' case reporting scheme set up in 1986 to facilitate the investigation of uncommon childhood conditions of public health and clinical importance in the UK and Ireland. Its methodology involves the monthly mailing of a card containing a menu of up to 12 reportable conditions to all clinically active paediatricians in the British Isles. Respondents either indicate any cases seen in the past month or make a nil return. The BPSU forwards details of respondents reporting cases to the investigators, who when obtain information from the clinician. The menu changes from time to time and studies undergo a rigorous selection process. In 1995, the BPSU held an international seminar to review lessons learned during its first decade which would improve and develop surveillance of paediatric disorders. Over the 9 years to mid-1995 a total of 34 studies took place (25 completed, nine still in progress) with a high respondent response rate (e.g. 90% in 1994). Underascertainment had been addressed by seeking, in parallel, other sources of cases, e.g. death registrations, laboratory reports, other relevant clinical specialists, and by use of capture-recapture techniques. Other specialties and countries have since followed the BPSU example providing opportunity for multispeciality and international studies. The latter were valuable, but required careful planning to standardize case definitions and laboratory techniques, otherwise geographical differences in the incidence of study disorders were difficult to interpret. The BPSU has facilitated studies which increased knowledge about a range of disorders and informed national policy decisions. It also increased diagnostic awareness and showed itself able to respond to public health emergencies. Its emulation in further countries will have similar benefits.

Adolescent↗