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Biomedical subjects

N Bell

Publications and source records attributed to N Bell.

At least 19 recordsLinked to original sources
PubMed2000

Comparison between low and high pressure suction drainage following axillary clearance.

AIM: We report the comparison of low (Exudrain) and high pressure (Redivac) drains in 69 patients following mastectomy and axillary clearance. METHODS: Volume of drainage was recorded daily for 8 days postoperatively. RESULTS: Comparison of daily drainage revealed no statistically significant difference between the two groups of patients (P>0.05). There were no complications specific to the drains and we found similar numbers of infective complications in both groups. Hospital stay was also similar in the two groups (P=0. 70). CONCLUSIONS: We conclude that the two drainage systems are equally effective in their drainage abilities although use of the low pressure may have an advantage over the high pressure system as it obviates the need for bottle changes and therefore requires less time and effort to manage.

Axilla↗
PubMed2000

Alendronate and estrogen effects in postmenopausal women with low bone mineral density. Alendronate/Estrogen Study Group.

The bisphosphonate alendronate and conjugated equine estrogens are both widely used for the treatment of postmenopausal osteoporosis. Acting by different mechanisms, these two agents decrease bone resorption and thereby increase or preserve bone mineral density (BMD). The comparative and combined effects of these medications have not been rigorously studied. This prospective, double blind, placebo-controlled, randomized clinical trial examined the effects of oral alendronate and conjugated estrogen, in combination and separately, on BMD, biochemical markers of bone turnover, safety, and tolerability in 425 hysterectomized postmenopausal women with low bone mass. In addition, bone biopsy with histomorphometry was performed in a subset of subjects. Treatment included placebo, alendronate (10 mg daily), conjugated equine estrogen (CEE; 0.625 mg daily), or alendronate (10 mg daily) plus CEE (0.625 mg daily) for 2 yr. All of the women received a supplement of 500 mg calcium daily. At 2 yr, placebo-treated patients showed a mean 0.6% loss in lumbar spine BMD, compared with mean increases in women receiving alendronate, CEE, and alendronate plus CEE of 6.0% (P < 0.001 vs. placebo), 6.0% (P < 0.001 vs. placebo), and 8.3% (P < 0.001 vs. placebo and CEE; P = 0.022 vs. alendronate), respectively. The corresponding changes in total proximal femur bone mineral density were +4.0%, +3.4%, +4.7%, and +0.3% for the alendronate, estrogen, alendronate plus estrogen, and placebo groups, respectively. Both alendronate and CEE significantly decreased biochemical markers of bone turnover, specifically urinary N-telopeptide of type I collagen and serum bone-specific alkaline phosphatase. The alendronate plus CEE combination produced slightly greater decreases in these markers than either treatment alone, but the mean absolute values remained within the normal premenopausal range. Alendronate, alone or in combination with CEE, was well tolerated. In the subset of patients who underwent bone biopsies, histomorphometry showed normal bone histology with the expected decrease in bone turnover, which was somewhat more pronounced in the combination group. Thus, alendronate and estrogen produced favorable effects on BMD. Combined use of alendronate and estrogen produced somewhat larger increases in BMD than either agent alone and was well tolerated.

Adult↗
PubMed1999

Clinical outcome of calcitriol therapy and patient education program on hyperparathyroidism.

The treatment of patients with hyperparathyroidism provides a challenge for the dialysis team. Interventions with calcitriol therapy, phosphate binders, motivational efforts, and education on diet and renal osteodystrophy can help to control parathyroid hormone (PTH). Effects of intervention were studied on 54 hemodialysis patients for 1 year, resulting in improved outcomes.

Calcitriol↗
PubMed1999

Identification of residues in dendrotoxin K responsible for its discrimination between neuronal K+ channels containing Kv1.1 and 1.2 alpha subunits.

Dendrotoxin (DTX) homologues are powerful blockers of K+ channels that contain certain subfamily Kv1 (1.1-1.6) alpha- and beta-subunits, in (alpha)4(beta)4 stoichiometry. DTXk inhibits potently Kv1.1-containing channels only, whereas alphaDTX is less discriminating, but exhibits highest affinity for Kv1.2. Herein, the nature of interactions of DTXk with native K+ channels composed of Kv1.1 and 1.2 (plus other) subunits were examined, using 15 site-directed mutants in which amino acids were altered in the 310-helix, beta-turn, alpha-helix and random-coil regions. The mutants' antagonism of high-affinity [125I]DTXk binding to Kv1. 1-possessing channels in rat brain membranes and blockade of the Kv1. 1 current expressed in oocytes were quantified. Also, the levels of inhibition of [125I]alphaDTX binding to brain membranes by the DTXk mutants were used to measure their high- and low-affinity interactions, respectively, with neuronal Kv1.2-containing channels that possess Kv1.1 as a major or minor constituent. Displacement of toxin binding to either of these subtypes was not altered by single substitution with alanine of three basic residues in the random-coil region, or R52 or R53 in the alpha-helix; accordingly, representative mutants (K17A, R53A) blocked the Kv1.1 current with the same potency as the natural toxin. In contrast, competition of the binding of the radiolabelled alphaDTX or DTXk was dramatically reduced by alanine substitution of K26 or W25 in the beta-turn whereas changing nearby residues caused negligible alterations. Consistently, W25A and K26A exhibited diminished functional blockade of the Kv1.1 homo-oligomer. The 310-helical N-terminal region of DTXk was found to be responsible for recognition of Kv1.1 channels because mutation of K3A led to approximately 1246-fold reduction in the inhibitory potency for [125I]DTXk binding and a large decrease in its ability to block the Kv1.1 current; the effect of this substitution on the affinity of DTXk for Kv1.2-possessing oligomers was much less dramatic (approximately 16-fold).

Amino Acid Sequence↗
PubMed1999

Employee drinking practices and work performance.

OBJECTIVE: The purpose of this study was to examine the independent effects of a variety of drinking indicators on self-reported work performance. METHOD: Data from a cross-sectional mailed survey (response rate = 71%) of managers, supervisors and workers (N = 6,540) at 16 worksites were analyzed. Average daily volume was computed from frequency and usual quantity reports. Drinking on the job included drinking during any of six workday situations. The CAGE was used to indicate alcohol dependence. Employees were also asked how frequently they drank to get high or drunk. Work performance was measured through a series of questions about work problems during the prior year. The number of times respondents experienced work performance problems was regressed on the four drinking measures, and a variety of demographic characteristics, job characteristics and life circumstances that might also negatively affect work performance. RESULTS: The frequency of self-reported work performance problems increased, generally, with all four drinking measures. In a multivariate model that controlled for a number of demographics, job characteristics and life-situations, average daily volume was no longer significantly associated with work performance but the other three drinking measures were. Interestingly, although moderate-heavy and heavy drinkers reported more work performance problems than very light, light, or moderate drinkers, the lower-level-drinking employees, since they were more plentiful, accounted for a larger proportion of work performance problems than did the heavier drinking groups. CONCLUSIONS: Employers should develop clear policies limiting drinking on the job and, in addition to employee assistance programs for problem drinkers, should develop worksite educational interventions aimed at informing all employees about the relationship between drinking behaviors and work performance.

Absenteeism↗
PubMed1998

Infant screening: the usefulness of the Bayley Infant Neurodevelopmental Screener and the Clinical Adaptive Test/Clinical Linguistic Auditory Milestone Scale.

We assessed the usefulness of the Bayley Infant Neurodevelopmental Screener (BINS) and the Clinical Adaptive Test/Clinical Linguistic Auditory Milestone Scale (CAT/CLAMS) for screening high-risk infant populations in a sample of 78 infants followed after premature birth and/or perinatal insults. Both measures were highly correlated with the Bayley Scales of Infant Development-II, but sensitivity and specificity analyses revealed disparities related to the tests administered and the cutoffs used. The BINS had optimal sensitivity (true positives) of 90% when referral was made for a BINS score of high or moderate. The CAT/CLAMS had excellent specificity (true negatives) of 95% to 98% but poor sensitivity (5%-36%). Until the cutoff issue can be clarified, clinicians should be cautious in using the CAT/CLAMS as the primary screening instrument in settings in which early identification of infants with developmental problems is the main goal.

Chi-Square Distribution↗
PubMed1998

Inhibitory effect of amiloride on the urokinase plasminogen activators in prostatic cancer.

The diuretic drug amiloride (AMLD), which competitively inhibits the catalytic activity of urokinase plasminogen activators (UPA), was used to study its effects on the proteolytic enzymes implicated in the invasiveness and metastases in a prostatic tumor model carrying two different sublines of adenocarcinoma of the prostate. Our data showed that UPA activity was significantly higher, both in the cytosol and pellet of R3327-AT3, a fast-growing highly metastatic and androgen-insensitive tumor, as compared to the G3327-G subline, a slow-growing nonmetastatic tumor of the prostate. The UPA activity in AT3 tumor dropped when the rats were treated with AMLD for 3 weeks. The UPA activity in the sera and tumor effusions from rats with AT3 tumor was significantly higher as compared to those with G subline tumor. The number of pulmonary metastatic foci was the same in untreated rats as compared to those treated with AMLD. The lymph node inspection after 3 weeks revealed no secondary tumor in the AMLD-treated group. The role of UPA in the metastases of prostate cancer is discussed.

Adenocarcinoma↗
PubMed1997

Mood and physiological effects of subcutaneous nicotine in smokers and never-smokers.

This study compared the effect of subcutaneous nicotine injections (2 x 0.3 mg and 2 x 0.6 mg) with saline on subjective and physiological measures in 18 never-smokers and 18 smokers (24-h nicotine deprived), under conditions of rest and cognitive testing. Prior to the injections the mood of the smokers had deteriorated to a level significantly below that of the never-smokers as a result of tobacco withdrawal. Cognitive tests caused reductions in calmness and increased alertness but there was no evidence of nicotine improving mood in either group under either condition. The 0.6 mg dose worsened mood in never-smokers and caused unpleasant symptoms (e.g. dizziness and arm pain) in both groups. Compared with smokers, never-smokers experienced stronger symptoms of nicotine toxicity and a greater reduction in alertness in response to the 0.6 mg dose, suggesting chronic tolerance to some nicotine effects in smokers. Nicotine produced similar increases in heart rate and decreases in finger pulse volume in both groups. Our results imply that if nicotine has a mood enhancing effect it occurs only after tolerance has been acquired to its primary adverse effects, and that its ability to reverse the mood deterioration caused by tobacco withdrawal is susceptible to situational factors such as our experimental conditions.

Adult↗
PubMed1997

State-level clustering of safety measures and its relationship to injury mortality.

This article proposes a social model of investigating injury mortality. The authors hypothesize that (1) state-level laws and regulations on safety cluster together in one or more groupings; (2) groupings of safety measures play a significant role in injury mortality; and (3) injury mortality is very highly associated with social structural variables. There is a clustering of safety policies, with five factors explaining 67 percent of variance, although no "master factor" was discovered. The strongest factor, explaining 21 percent of variance, includes three gun laws and low speed limits before the 1973 federal law. One factor is the most global in that it taps three distinct areas, including helmet laws, minor blood alcohol levels, and smoke detectors, though it only explains 7.5 percent of variance. The only factor that remains in a regression for injury mortality is one that includes strong seat belt laws and strong enforcement of those laws, though in the direction opposite to that hypothesized. This factor, along with percentage rural and environmental spending per capita, is significant for both motor vehicle and non-motor vehicle mortality. For motor vehicle mortality alone, deaths are higher in states with higher percentages of Hispanics and fewer people receiving food stamps and AFDC. Many factors that usually predict individual injury mortality do not hold at the state level, suggesting the usefulness of looking at social factors for new insights into injury mortality and prevention.

Adolescent↗
PubMed1996

Cognitive performance effects of subcutaneous nicotine in smokers and never-smokers.

In a double-blind placebo-controlled crossover study the effects of two doses of subcutaneous nicotine and saline were compared on a range of performance measures in 18 abstaining smokers and 18 never-smokers. Each subject received two injections (40 min apart) of saline, 0.3 mg nicotine, or 0.6 mg nicotine in a balanced order over three sessions. Performance was assessed before and after the injections on nine tests [news recall, Sternberg memory task, finger tapping, logical reasoning, rapid visual information processing (RVIP), long-term word recognition, digit recall, Stroop test, and critical flicker fusion threshold]. In the abstinent smokers, nicotine produced significantly faster correct responses on the logical reasoning test, more target hits, faster reaction times and improved sensitivity on the RVIP task, and more correct responses on word recognition. In never-smokers, nicotine produced faster reaction times on the RVIP and digit-recall tasks, although in the latter case this was at the expense of fewer correct responses. There were no significant differences between the two groups' responses to nicotine but smokers performed worse than never-smokers prior to injections, even controlling for background characteristics. These results are consistent with other recent research suggesting a primary effect of nicotine in enhancing cognitive performance.

Adult↗
PubMed1996

Employee attitudes toward work-site alcohol testing.

Few studies have been published on how employees feel about work-site alcohol testing. By mail, we surveyed employees (n = 6370) at 16 corporate work sites stratified by type of work force, industrial setting, and managerial tolerance toward drinking. We queried respondents about their drinking on the job and support for work-site alcohol testing under three conditions: pre-employment testing, testing after an accident, and random testing. Sixty-five percent of respondents supported pre-employment testing, 81% supported testing after an accident, and 49% supported random testing. Support was relatively consistent across hierarchy (managers, supervisors, and workers) but different by age, education, occupation, type of work force, and perceived exposure to occupational hazards. Support for work-site alcohol testing was highest among blue-collar workers whose jobs involved manufacturing or exposure to work-site hazards.

Accidents, Occupational↗
PubMed1996

Why are most drowning victims men? Sex differences in aquatic skills and behaviors.

Men have higher drowning rates than women for most age groups. Data from a 1991 national household survey (n = 3042) on aquatic activities were used to examine hypotheses about differential drowning rates by sex. Men and women were compared by (1) exposure to aquatic environments; (2) frequency of aquatic activities involving or potentially involving, submersion; (3) swimming training and ability; (4) aquatic risk-taking behaviors; and (5) alcohol use on or near the water. Men had elevated risks for exposure, risk taking, and alcohol use. It was concluded that several factors contribute to their relatively high drowning rates, including a possible interaction between overestimation of abilities and heavy alcohol use.

Adolescent↗
PubMed1996

Work-site variation in managerial drinking.

To assess cross-work-site variation in the general drinking behaviors (on and off the job) of employees, we conducted a cross-sectional survey of managers (n = 7255) at 114 places of work located throughout the continental United States. The work-site mean for the total number of drinks consumed on a typical drinking day ranged from 1.4 to 3.17, a two-fold differential. Regression analysis showed an independent work-site effect, controlling for respondents demographics and type of work. This finding suggests that modifiable work-site characteristics could influence what employees drink on and off the job.

Administrative Personnel↗
PubMed1995

Hereditary sensory and autonomic neuropathy with cataracts, mental retardation, and skin lesions: five cases.

We report the clinical and electrophysiologic data on five subjects from two families with severe sensory and autonomic neuropathy who also exhibited peroneal muscular atrophy with the electrophysiologic features of an axonopathy, congenital cataracts, mental retardation, and skin lesions. One patient had hearing loss. Autosomal recessive inheritance was probable in both families.

Adult↗
PubMed1995

The electronic patient record system: the journey begins now.

The movement toward an electronic patient record parallels our efforts to increase the efficiency and the effectiveness of our health care delivery system. In the final article in our continuing series on the computerized, patient-based medical record, the author explains the evolutionary time line toward reaching this goal.

Efficiency, Organizational↗