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Biomedical subjects

D Black

Publications and source records attributed to D Black.

At least 73 records · Page 4Linked to original sources
PubMed1998

Surgery in patients with hemoglobin SC disease. Preoperative Transfusion in Sickle Cell Disease Study Group.

While surgery is commonly required for complications related to hemoglobin SC (HbSC) disease, little is known about the perioperative complications or the indications for preoperative transfusion in this group. We describe the patient characteristics, preoperative transfusion regimens, and outcome in 92 patients with HbSC and sickle-variants undergoing elective surgery. Thirty-eight percent of the patients were transfused preoperatively. Patients transfused were more likely to have been hospitalized in the year prior to the surgery and scheduled for abdominal procedures. Abdominal and ear, nose and throat procedures were the most common surgeries in our study. The overall complication rate was 18% and sickle cell-related complications occurred in 9% of patients. In patients undergoing intra-abdominal procedures, the incidence of sickle cell-related complications was significantly higher in those patients not transfused prior to their surgery (35 vs. 0%). There were two deaths. We recommend selective use of preoperative transfusion in patients with HbSC disease undergoing surgery. Transfusion appears to be beneficial in abdominal cases but is not necessary with minor procedures such as myringtomy.

Adult↗
PubMed1998

Bone mineral density is a predictor of survival.

The purpose of this study was to examine the relationship between bone mineral density (BMD) and survival in both sexes and to compare BMD with other established risk factors such as blood pressure and cholesterol. A population-based prospective study of 1924 individuals (850 men, 1074 women) was performed in Göteborg from 1980 to 1983. Measurements of BMD were obtained in 1468 (76%) of the participants (653 men, 815 women). This selection of individuals generated 10,965 person years, and death was registered for 289 men and 197 women in the 7-year period (2661 days) after bone mineral measurement. Later information on date of death was obtained from the official population register. This information covers 7 years from the time of survey of the last examined participant (in Dec. 1983). At the beginning of the study, BMD was measured in the calcaneus by dual photon absorptiometry (DPA), and blood pressure, serum cholesterol, serum triglycerides, and body mass index (BMI) were also recorded. The study was coordinated with the National Register of Causes of Death and the National Cancer Register. A modified version of the Cox proportional hazards model was used to calculate and determine the age-adjusted relations between nontrauma mortality and BMD. When the various quartiles of BMD were compared prospectively from 70, 75, and 79 years of age with survival figures during the 2661-day follow-up period, the first and the second quartiles with the lowest BMD at entry showed the lowest survival rate in both men (P = 0.01) and women (P = 0.01). A decrease of 1 SD of BMD in a univariate analysis was associated with a 1.39-fold increase in mortality in both men (95% confidence interval 1.25-1.56, P < 0.001) and women (95% confidence interval 1.22-1.58, P < 0.001), and a multivariate analysis demonstrated a relative risk of 1.23 (95% confidence interval 1.10-1.41, P < 0.001) in men and 1.19 (95% confidence interval 1.02 to 1.39, P = 0.019) in women. All relations were adjusted for sex, age, and follow-up. This study indicates that BMD is a predictor of survival, especially for subjects over 70. Bone mineral density was found to be a better predictor of death than blood pressure and cholesterol. This study indicates that, after adjustments have been made for diseases, low bone mass is an independent predictor of mortality and might be a marker of general health or functional aging. Its measurement might therefore be a valuable tool in general health investigations.

Aged↗
PubMed1998

An in vivo method for measuring the mechanical properties of the skin using ultrasound.

In this study, we report a new and original device called the "echorheometer," comprising a suction system with an ultrasound scanner (A-mode, TM-mode and B-mode) that enables the simultaneous visualization and measurement of the deformation of skin structures in vivo. With the scanner described here, high resolution is obtained using a strongly focused, wide-band 20-MHz center frequency transducer, with an axial resolution of 0.07 mm. This device can determine, noninvasively, not only those skin structures that are involved in the deformation, but also their morphological variation and their extent of involvement with the degree of stress applied. Using this device, the behavior of the dermis and subcutaneous fat, while under suction, was investigated on the volar forearm of 10 volunteers. The results showed that the resistance to the applied vertical stress is essentially due to the dermis rather than the subcutaneous fat, and that there is a certain amount of infiltration of fluid into the tissues under suction. In addition, it was shown that the dermal response to an applied suction is initially due to its own natural tension and that, with increasing deformation, the intrinsic dermal elasticity has a greater contribution to the resistance of stress. With this information, we hope to develop a mechanical model to define appropriate mechanical parameters for skin. This will allow the evaluation of changes in the dermis and also enable therapeutic intervention to be assessed. Furthermore, it could also be applied to studies of skin ageing and the assessment of cosmetic product efficacy (emolliency, hydratation, etc.).

Adult↗
PubMed1998

Antibiotic resistance in community-acquired respiratory tract infections: current issues.

OBJECTIVE: In recent years, antibiotic resistance has emerged as an important global problem. The major goal of this review is to update important issues pertaining to antibiotic resistance, with an emphasis on antibiotic resistance involving community-acquired respiratory pathogens. In addition, this review examines potential reasons why antibiotic resistance has increased in recent years, how clinicians can better understand commonly used laboratory antibiotic resistance tests, and possible solutions to the increasing problem of antibiotic resistance. The article emphasizes the diagnosis, therapy, and prevention of antibiotic-resistant infections. DATA SOURCES: We identified relevant English-language articles through MEDLINE search (1966 to March 1998). All articles related to antibiotic resistance and the scope of the articles included original investigative articles, reviews, letters, and editorials. In addition, we selected additional references from the bibliographies of the identified articles. STUDY SELECTION: We selected articles for detailed review if they provided direct insight into the cause of antibiotic resistance, testing for antibiotic resistance, or the treatment of antibiotic resistance. Most, but not all, of the articles selected pertained to antibiotic resistance and respiratory tract infections. We performed a detailed review on approximately 40% of the originally selected articles. RESULTS: Multiple factors that play a significant role in the development of antibiotic resistance include the overuse of antibiotics in both humans and animals, situations such as day care that enhance transmission via frequent close personal contact, and widespread dissemination of resistant strains via global travel. Most respiratory pathogens have developed resistance to commonly used antibiotics either by producing beta-lactamase or by altering binding site proteins. CONCLUSIONS: In many regions of the United States, the level of antibiotic resistance has impacted the clinical management of common respiratory pathogens. Future efforts to curtail antibiotic resistance will require a concerted effort in multiple areas, particularly enhanced epidemiologic surveillance to better detect resistance trends, judicious use of antibiotics, and new drug development.

Animals↗
PubMed1998

Telephone medical care of patients with HIV/AIDS.

It has been reported that primary care physicians make 27% of their patient contacts by telephone. With the knowledge that more than 90% of the population has access to a telephone, it is reasonable to propose that the telephone might be employed in a more structured and organized manner for improved, cost-effective medical care. In the current study, two diverse practices (multiphysician and university-affiliated HIV/AIDS clinic, private practice specializing in HIV/AIDS care), both of which used the telephone as having a central role in patient management, were critically observed and reported through three case reports. The results indicate that personnel other than the primary physician provider, such as the triage nurse, may handle a large percentage of calls and successfully manage numerous psychologic and health care issues for the patient, referring, when necessary, appropriate medical inquiries to the physician. It is recommended that physicians take the time to construct sound protocols for clinic personnel to manage patient inquiries by telephone.

Acquired Immunodeficiency Syndrome↗
PubMed1998

The kappa opioid receptor is associated with the perception of visceral pain.

mu-, delta- and kappa-opioid receptors are widely expressed in the central nervous system where they mediate the strong analgesic and mood-altering actions of opioids, and modulate numerous endogenous functions. To investigate the contribution of the kappa-opioid receptor (KOR) to opioid function in vivo, we have generated KOR-deficient mice by gene targeting. We show that absence of KOR does not modify expression of the other components of the opioid system, and behavioural tests indicate that spontaneous activity is not altered in mutant mice. The analysis of responses to various nociceptive stimuli suggests that the KOR gene product is implicated in the perception of visceral chemical pain. We further demonstrate that KOR is critical to mediate the hypolocomotor, analgesic and aversive actions of the prototypic kappa-agonist U-50,488H. Finally, our results indicate that this receptor does not contribute to morphine analgesia and reward, but participates in the expression of morphine abstinence. Together, our data demonstrate that the KOR-encoded receptor plays a modulatory role in specific aspects of opioid function.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1998

Psychological stress and burnout in medical students: a five-year prospective longitudinal study.

The aim of this study was to assess psychological morbidity and symptoms of burnout in medical students during their undergraduate training, and to identify baseline factors that predict psychological morbidity in students in the final year of the course. It was a 5-year prospective longitudinal cohort study. Students were assessed in years 1, 4 and 5 of their medical undergraduate training by means of the GHQ-12 and the Maslach Burnout Inventory. 172 (84.3%), 157 (77.0%) and 155 (75.9%) students out of an original group of 204 completed assessments in years 1, 4 and 5, respectively. 18 students were above threshold on the GHQ-12 on all three occasions, 25 on two occasions and 43 on one occasion; 69 students were never a 'case'. Students who were cases on two or more occasions were more likely to find the medical course stressful during the first year, but not subsequent years. There was no significant difference between the percentages of men and women who scored as cases on the GHQ-12 in any of the years. The best predictor of psychological morbidity in the final year of the course was the GHQ-12 score in year 1. This study suggests that a small group of students repeatedly experience psychological distress during their medical training.

Alcohol Drinking↗
PubMed1998

The Effect of Atorvastatin on the Human Lens After 52 Weeks of Treatment.

BACKGROUND: The effect of atorvastatin calcium (Lipitor, Parke-Davis, Morris Plains, NJ) on the crystalline lenses of hypercholesterolemic patients was evaluated and compared with that of lovastatin after 52 weeks of treatment to reduce cholesterol levels. METHODS AND RESULTS: Six hundred ninety-six atorvastatin-treated and 235 lovastatin-treated patients completed a large safety study that included an ophthalmologic examination. Efficacy was evaluated as mean percent change from baseline in low-density lipoprotein (LDL) cholesterol. Patients received atorvastatin, 10 or 20 mg, or lovastatin, 20 or 40 mg, once daily for either 36 or 52 weeks. Patients were evaluated by slit-lamp examination, and a standardized format was used to describe the findings. Best corrected visual acuity was measured using the Snellen chart. Patients treated with atorvastatin had significantly (P </=.05) greater decreases in LDL cholesterol than those treated with lovastatin (37% vs 29%). Although some patients in both groups experienced various lenticular opacities, none were considered unexpected. In addition, there were no significant (P </=.05) differences in the distribution of cortical opacities and spokes right eye (OD) and left eye (OS) and posterior subcapsular opacity (OS) between the atorvastatin and lovastatin groups. In general, the percent deterioration in best corrected visual acuity was similar in both groups. Overall, there were no clinically significant differences in the development of lenticular opacity between patients treated with atorvastatin and those treated with lovastatin. CONCLUSIONS: Treatment with atorvastatin, 10 or 20 mg, significantly reduced LDL-cholesterol (P <.05) and was not associated with an increased risk of lenticular opacity development compared with lovastatin, a widely prescribed compound in the same class of drugs.

Journal Article↗
PubMed1998

Intermediate not indeterminate care.

Increasing demands, limited resources and an aging population are driving the development of alternatives to the full acute hospital bed. This review considers some opportunities and pitfalls, and proposes some principles for practice.

Aged↗
PubMed1998

[Cerebellar degeneration following acute lithium intoxication].

Lithium is a neurotoxin with a particular affinity for the cerebellum. The risk of permanent neurotoxic sequelae of lithium is increased by the concomitant use of certain conventional neuroleptics. We report two new cases of lithium neurotoxicity; one received lithium alone, not in combination with a neuroleptic. Both cases showed severe cerebellar atrophy on brain CT and MRI. Additional factors such as dehydration, systemic infection, other medications, or rapid correction of frequently-coexisting hyponatremia may contribute to the risk of lithium neurotoxicity. We discuss possible pathophysiologic mechanisms and preventive measures.

Antipsychotic Agents↗
PubMed1997

A multicenter, double-blind, one-year study comparing safety and efficacy of atorvastatin versus simvastatin in patients with hypercholesterolemia.

We directly compared the safety and efficacy of atorvastatin and simvastatin in hypercholesterolemic patients. This 1-year, randomized, double-blind study was performed at 9 community- and university-based research hospitals in Australia. One-hundred seventy-seven patients between the ages of 18 and 80 years with baseline low-density-lipoprotein (LDL) cholesterol > or = 4.14 and < or = 7.76 mmol/L (160 and 300 mg/dl, respectively) and triglycerides < or = 4.52 mmol/L (400 mg/dl) received once-daily dosing with atorvastatin (Lipitor) 10 mg or simvastatin (Zocor) 10 mg. At week 16, the dose of medication was titrated to atorvastatin 20 mg or simvastatin 20 mg if patients did not meet LDL cholesterol target of < or = 3.36 mmol/L (130 mg/dl). Efficacy was reported as percent change from baseline in LDL cholesterol, total cholesterol, very low density lipoprotein cholesterol, total triglycerides, high-density lipoprotein cholesterol, apolipoproteins AI and B, and lipoprotein(a). Atorvastatin caused significantly greater reductions from baseline than did simvastatin for LDL cholesterol, total cholesterol, very low density lipoprotein cholesterol, triglycerides, and apolipoprotein B (p <0.05). No patient in either treatment group had clinically important elevations in creatine phosphokinase, alanine aminotransaminase, or aspartate aminotransaminase. No serious adverse events were considered associated with treatment. With atorvastatin 10 mg, 46% of the patients achieved LDL cholesterol target goal by week 16, whereas only 27% of the simvastatin patients achieved the target goal at the 10-mg dose. This cholesterol-lowering profile affords utility in many patient types.

Adult↗
PubMed1997

Comparison of one-year efficacy and safety of atorvastatin versus lovastatin in primary hypercholesterolemia. Atorvastatin Study Group I.

This double-blind study to evaluate long-term efficacy and safety of atorvastatin was performed in 31 community- and university-based research centers in the USA to directly compare a new 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor (reductase inhibitor) to an accepted drug of this class in patients with moderate hypercholesterolemia. Participants remained on a cholesterol-lowering diet throughout the study. One thousand forty-nine patients were randomized to receive atorvastatin 10 mg, lovastatin 20 mg, or placebo. At 16 weeks the placebo group was randomized to either atorvastatin or lovastatin treatment. At 22 weeks, patients who had not met low-density lipoprotein (LDL) cholesterol target levels doubled the dose of reductase inhibitor. Efficacy evaluation was mean percent change from baseline in LDL cholesterol, triglycerides, total cholesterol, high-density-lipoprotein cholesterol, and apolipoprotein B (apoB). Safety profiles as determined by change from baseline in laboratory evaluations, ophthalmologic parameters, and reporting of adverse events were similar for the 2 reductase inhibitors. After 52 weeks, the atorvastatin group maintained a significantly greater reduction in LDL cholesterol (-37% vs -29%), triglyceride (-16% vs -8%), total cholesterol (-27% vs -21%), and apoB (-30% vs -22%) (p <0.05). More patients receiving atorvastatin achieved LDL cholesterol target levels than did lovastatin patients (78% vs 63%, respectively), particularly those with coronary heart disease (37% vs 11%, respectively). Atorvastatin is highly effective and well tolerated in patients with primary hypercholesterolemia with no increased risk of adverse events.

Analysis of Variance↗