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Biomedical subjects

David Cohen

Publications and source records attributed to David Cohen.

At least 55 records · Page 3Linked to original sources
PubMed2004

Factors associated with psychotropic drug use among community-dwelling older persons: A review of empirical studies.

BACKGROUND: In the many descriptive studies on prescribed psychotropic drug use by community-dwelling older persons, several sociodemographic and other factors associated with drug use receive inconsistent support. METHOD: Empirical reports with data on at least benzodiazepine or antidepressant drug use in samples of older persons published between 1990 and 2001 (n = 32) were identified from major databases and analyzed to determine which factors are most frequently associated with psychotropic drug use in multivariate analyses. Methodological aspects were also examined. RESULTS: Most reports used probability samples of users and non-users and employed cross-sectional designs. Among variables considered in 5 or more reports, race, proximity to health centers, medical consultations, sleep complaints, and health perception were virtually always associated to drug use. Gender, mental health, and physical health status were associated in about two-thirds of reports. Associations with age, marital status, medication coverage, socioeconomic status, and social support were usually not observed. CONCLUSIONS: The large variety of methods to operationalize drug use, mental health status, and social support probably affected the magnitude of observed relationships. Employing longitudinal designs and distinguishing short-term from long-term use, focusing on samples of drug users exclusively, defining drug use and drug classes more uniformly, and utilizing measures of psychological well-being rather than only of distress, might clarify the nature of observed associations and the direction of causality. Few studies tested specific hypotheses. Most studies focused on individual characteristics of respondents, neglecting the potential contribution of health care professionals to the phenomenon of psychotropic drug use among seniors.

Journal Article↗
PubMed2004

New computer-guided scanner for improving CO2 laser-assisted microincision.

The objective was to clinically test a new computer-guided scanner designed for CO2 laser-assisted microincision. The scanner-assisted beam travels across the target as a straight or curved incision line. Line length and beam penetration can be adjusted. The studied population, 155 cases, encompassed benign lesions as well as early cancers of the larynx. Operating time was compared with that required for similar operations performed with the Acuspot micromanipulator. Laser-produced coagulation thickness at the incision was measured on 41 operative specimens. The scanner-assisted incision and dissection were more accurate and required up to 30% less time than with a manually guided beam. Postoperative follow-up was straightforward. The coagulation thickness was less than 10 microm for phonomicrosurgery and less than 20 microm for other surgical procedures. The scanner-assisted incision is more accurate than that attained manually.

Humans↗
PubMed2004

Mammalian PAR-1 determines epithelial lumen polarity by organizing the microtubule cytoskeleton.

Epithelial differentiation involves the generation of luminal surfaces and of a noncentrosomal microtubule (MT) network aligned along the polarity axis. Columnar epithelia (e.g., kidney, intestine, and Madin-Darby canine kidney [MDCK] cells) generate apical lumina and orient MT vertically, whereas liver epithelial cells (hepatocytes and WIFB9 cells) generate lumina at cell-cell contact sites (bile canaliculi) and orient MTs horizontally. We report that knockdown or inhibition of the mammalian orthologue of Caenorhabditis elegans Par-1 (EMK1 and MARK2) during polarization of cultured MDCK and WIFB9 cells prevented development of their characteristic lumen and nonradial MT networks. Conversely, EMK1 overexpression induced the appearance of intercellular lumina and horizontal MT arrays in MDCK cells, making EMK1 the first known candidate to regulate the developmental branching decision between hepatic and columnar epithelial cells. Our experiments suggest that EMK1 primarily promotes reorganization of the MT network, consistent with the MT-regulating role of this gene product in other systems, which in turn controls lumen formation and position.

Animals↗
PubMed2004

Mandated pain scales improve frequency of ED analgesic administration.

A retrospective study design was used to determine the effect of introducing a mandated verbal numeric pain scale on the incidence and timing of analgesic administration in the ED. Consecutive patients presenting with renal colic, extremity trauma, headache, ophthalmologic trauma, and soft tissue injury were included. 521 encounters were reviewed before and 479 encounters after the introduction of the pain scale. Groups were similar in baseline characteristics. Analgesic use increased from 25% to 36% (p < 0.001), and analgesics were administered more rapidly after the scale was introduced (113 minutes vs. 152 minutes, p = 0.09). Analgesic use correlated with pain severity. Patients undergoing diagnostic testing were less likely to receive analgesics, especially when presenting with a headache (p < 0.001). We conclude that use of a pain scale at triage significantly increases use of analgesia, and shortens the time till its administration. Patients undergoing diagnostic workups were less likely to receive analgesia.

Adult↗
PubMed2004

Sporadic Creutzfeldt-Jakob disease presenting with nonconvulsive status epilepticus.

Creutzfeldt-Jakob disease (CJD) is a rare prion disease characterized by a spongiform encephalopathy in humans. Although the characteristic triad of myoclonus, dementia, and periodic EEG activity is easy to recognize, unusual manifestations of the disease may be challenging and create a diagnostic dilemma. We report a case of CJD that occurred in a 26-year-old patient who presented with a receptive (Wernicke's) aphasia secondary to nonconvulsive status epilepticus.

Adult↗
PubMed2004

Health economics and genetic service development: a familial cancer genetic example.

Advances in genetics are allowing a greater number of clinical genetics services to be offered to individuals with family histories of particular diseases. It is important that such services are not allowed to proliferate before they have been properly evaluated in terms of both their clinical and cost-effectiveness. A randomised controlled study of a new clinical genetics service in Wales for women with a family history of breast cancer has been undertaken. The health service costs from initial consultation and counselling through to mutation testing within families were assessed, along with patient travel costs. The extra cost of specialist genetics assessment (intervention) was pound 16.36 higher per woman than assessment by a breast surgeon at a District General Hospital (control). A further cost of pound 46.42 per initially presenting woman was also generated as a result of further counselling within the families of 48, and testing within the families of 36 of the 412 original presenting women. An explanation is given here of the costing methodology as an illustration of what is involved in such an exercise.

Adult↗
PubMed2004

Unconventional indicators of drug dependence among elderly long-term users of benzodiazepines.

A quarter of the elderly population is prescribed benzodiazepines (BZD). This has led to growing concerns about drug dependence and the validity of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for dependence to a substance. This study aimed to understand how dependence was experienced by long-term BZD users. Interviews were conducted with 45 elderly persons who had been using BZDs for an average of nine years. These users' comments suggest six indicators of dependence: self-identifying as a dependent user, invoking multiple stressors to justify BZD use, using BZD to cope with anticipated stressors, trivializing the dangers of BZDs, keeping a supply in reserve, having previously tried and failed to stop, and reducing the dosage. Our results stress the need to take a more elaborate, person-centered view of dependence.

Activities of Daily Living↗
PubMed2004

Pharmacological treatment of adolescent major depression.

Antidepressant agents are widely prescribed for adolescents, although specific data regarding their efficacy in this age range are limited. The aims of the present article are to review research findings regarding the use of antidepressant drugs for adolescent depression and to discuss the main results in light of our clinical experience. Only 13 controlled trials on the use of antidepressant drugs for adolescent major depression are available in the literature. Six studies evaluated the efficacy of tricyclic antidepressants, yet they only included 196 adolescents altogether. Seven studies, including a total of 1,403 patients, evaluated the efficacy of three specific serotonin reuptake inhibitors: fluoxetine, paroxetine, and sertraline. Based on published data, serotonin reuptake inhibitors appear to be the first-line psychopharmacologic treatment for adolescent depression, as three compounds (fluoxetine, paroxetine, and sertraline) appeared to be effective in this indication. Conversely, all published studies failed to demonstrate that the tricyclic antidepressants were superior to placebo. Several questions remain open and are discussed: How should we use available scientific data in clinical practice? Are there nonspecific factors implicated in treatment response? Is there a serotonin hypothesis for juvenile depression? What are the priorities for future research?

Adolescent↗
PubMed2004

Tardive dystonia induced by atypical neuroleptics: a case report with olanzapine.

We report the case of a 17-year-old-boy with schizophrenia who developed tardive dystonia after 9 months of treatment with olanzapine. This case and the relevant literature show that when neuroleptic treatment is indicated, switching to another atypical neuroleptic might be helpful for both tardive dystonia and schizophrenia. In such a case, clozapine appears to be the first-line therapeutic option.

Adolescent↗
PubMed2004

Female sex hormones protect red blood cells from damage after trauma-hemorrhagic shock.

BACKGROUND: Trauma/hemorrhagic shock (T/HS) is known to cause changes in red blood cell (RBC) deformability and resting shape. Our previous studies have shown that proestrus female rats are more protected from shock-induced RBC damage than diestrus females or males. However, it is unclear whether female or male sex hormones can influence the severity of these alterations. METHODS: Red blood cell deformability and shape were examined in proestrus female rats, and oophorectomized female rats, as well as in castrated and non-castrated male rats (5-10 animals per group) subjected to T/HS. Red blood cell deformability was measured by laser ektacytometry whereas erythrocyte shape was evaluated by scanning electron microscopy. RESULTS: Proestrus female rats subjected to T/HS did not show either significant RBC deformability changes (decrease in elongation index) or shape alterations (increase in the percentage of reversibly and irreversibly changed cells). Oophorectomized rats demonstrated more severe RBC changes than did non-oophorectomized rats. The degree of RBC damage was the same in castrated and non-castrated males, which was significantly worse than in proestrus females. CONCLUSIONS: Removal of female sex hormones increases the severity of T/HS-induced RBC changes, indicating that female sex hormones protect against RBC damage. In contrast, male sex hormones do not appear to modulate T/HS RBC dysfunction.

Analysis of Variance↗
PubMed2004

Small volume albumin administration protects against hemorrhagic shock-induced bone marrow dysfunction.

BACKGROUND: Unexpected immunomodulatory effects of colloids and crystalloids prompted an investigation of albumin's ability to prevent bone marrow (BM) suppression following trauma/hemorrhagic shock (T/HS: laparotomy + MAP 30 for 90 mins). METHODS: In vitro: Normal rat BM was plated for granulocyte-macrophage (CFU-GM) and erythrocyte colony forming units (BFU-E) with 2% v/v plasma from sham (T/SS) or T/HS rats and albumin (2-8 mg/mL). In vivo: Male rats (n = 4/group) were subjected to T/SS or T/HS and resuscitated with shed blood and twice the volume as Lactated Ringer's (LR) or blood and 1, 2, or 3 mL of albumin (50 mg/mL). Bone marrow harvested 3 hours post-resuscitation was plated for CFU-GM and BFU-E. RESULTS: In vitro: T/HS plasma decreased both CFU-GM and BFU-E growth as compared with T/SS, whereas increasing doses of albumin showed dose-dependent improvement in progenitor growth (p < 0.05). In vivo: The suppression of BM red and white cell progenitor growth seen in T/HS+LR rats as compared with T/SS was fully prevented by as little as 1 mL of albumin (p < 0.05). CONCLUSIONS: Small doses of albumin fully restore CFU-GM and BFU-E to sham values. We postulate that the binding of circulating toxic factors by albumin may play a role in this prevention of T/HS-induced BM suppression.

Albumins↗
PubMed2004

Resource effects of training general practitioners in risk communication skills and shared decision making competences.

RATIONALE, AIMS AND OBJECTIVES: Involving patients more in decisions about their own care requires doctors to be trained in effective ways of communicating information and in developing competences to negotiate levels of patient involvement which are most appropriate for each case. The aim of this study was to determine the cost of such training and identify which service resource variables are subsequently affected. METHODS: An explanatory cluster randomized crossover trial was carried out which involved training general practitioners (GPs) in the use of risk communication (RC) tools, shared decision making (SDM) competences or both. Continuing care by GPs of patients with one of four chronic conditions (menopausal symptoms, menorrhagia, atrial fibrillation, prostatism) was reviewed before and after training. Cost of training was assessed by prospective monitoring of resources used. Data on prescribing, referrals and investigations were collected via questionnaires to participating practitioners. Data on follow-up GP consultations were extracted from medical records. Three two-level logistic models were performed to investigate the probability of training having an effect on prescribing, referrals and investigations ordered at the review consultation. RESULTS: Training cost pound 1218 per practitioner which increased the cost of a consultation by pound 2.89. Training in SDM or combined with RC significantly affected the probability of a prescription being issued to women with menopausal symptoms and menorrhagia (although RC on its own had no effect) but did not significantly affect prescribing for patients with prostatism or atrial fibrillation. It did not significantly affect the probability of investigations, referrals or follow-up GP visits for any of the conditions. CONCLUSION: Unless training has a major influence on consultation length, it is unlikely to have any major impacts on cost.

Chronic Disease↗
PubMed2003

Estimating the marginal value of 'better' research output: 'designed' versus 'routine' data in randomised controlled trials.

We recently completed a study which demonstrated that the costs of health technology assessment (HTA) by randomised controlled trial (RCT) can be reduced by substituting routine datasets for data designed and collected specifically for a trial. This cost reduction, however, had the effect of reducing the quality of the research output. In the present study we attempted to tease out the values attached to the 'better' information provided by designed data RCTs using a mock grants committee. Two valuation techniques, implied values and willingness to pay, were used. Ex ante valuations were determined by comparing alternative research proposals - a more costly version using designed data and a cheaper version using routine data. Ex post valuations were determined by comparing results of both versions. The exercise was performed on four exemplar studies. Overall, the committee expressed a general lack of trust towards routine data both ex ante and ex post and placed high values on the better information from the designed data studies - particularly information on preferences. This suggests that currently available routine datasets are not perceived to be able to provide efficient alternatives to designed data for RCTs.

Blood Transfusion, Autologous↗
PubMed2003

Burn-induced red blood cell deformability and shape changes are modulated by sex hormones.

BACKGROUND: Burns are known to cause changes in red blood cell (RBC) deformability and resting shape. However, it is unclear whether sex and sex hormones can influence the severity of these alterations. METHODS: Red blood cell deformability and shape were examined in proestrus and diestrus female rats, ovariectomized female rats, as well as castrated and non-castrated male rats (6 animals per group) subjected to scald burn. Red blood cell deformability was measured by laser ektacytometry and erythrocyte shape was evaluated by scanning electron microscopy. RESULTS: Burn-induced RBC deformability changes (decrease in elongation index) and shape alterations (increase in the percentage of reversibly and irreversibly changed cells) were less severe in proestrus females than in diestrus females or males. Ovariectomized rats demonstrated more severe RBC changes than non-ovariectomized ones. The degree of RBC damage was the same in castrated and non-castrated males. CONCLUSIONS: Removal of female sex hormones increases the severity of burn-induced RBC, indicating that female sex hormones protect against burn-induced RBC dysfunction. In contrast, male sex hormones do not appear to modulate burn-induced RBC dysfunction.

Animals↗
PubMed2003

Clinical and lay preferences for the explicit prioritisation of elective waiting lists: survey evidence from Wales.

Waiting lists are a persistent feature of public health care systems. The United Kingdom National Health Service (NHS) is considering priority scoring systems as a means of ensuring that patients are treated according to clinical need rather than maximum waiting time targets. Our objective was to elicit the preferences of those involved in the finance, delivery and receipt of elective health care regarding the clinical and social factors that should and should not determine waiting time. We conducted a postal survey of 750 general practitioners, 500 consultants, 29 health authority commissioners and 1000 members of the general public across Wales. We found both professional and lay support for a more explicit system of rationing access to elective health care by waiting list. The majority of each of the survey groups believe that level of pain, rate of deterioration of disease, level of distress and level of disability should play the most influential role in determining waiting times. They agree that age, ability to pay, cost of treatment, evidence of cost-effectiveness, existence of dependants, and self-inflicted ill health should have little or no influence on patient priority. In conclusion, were the NHS to widen its use of waiting list priority scoring systems, our study suggests that there may be some degree of consensus as to the criteria to be used.

Attitude of Health Personnel↗
PubMed2003

Apical surface formation in MDCK cells: regulation by the serine/threonine kinase EMK1.

It has recently become evident that basic mechanisms for the establishment of cell polarity are conserved between epithelial and nonepithelial systems. The vast catalogue of known gene products involved in various aspects of invertebrate and yeast cell polarity provides a repertoire of candidate proteins that can be tested for their roles in the organization of mammalian epithelia. Here, we describe cell biological approaches to study the development and maintenance of cell polarity in Mardin-Darby canine kidney (MDCK) cells, an established mammalian model cell line for simple epithelia. The assays allowed us to characterize the Caenorhabditis elegans PAR-1 homologue EMK1 as a novel regulator of apical surface formation in epithelial cells.

Cell Line↗