Search PubMed⌕ Search

Biomedical subjects

C Anderson

Publications and source records attributed to C Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1997

Effectiveness and economic impact of antidepressant medications: a review.

This article reviews the existing literature on the pharmacoeconomics and effectiveness of antidepressant medications. Although selective serotonin reuptake inhibitors (SSRIs) have not proved to be more efficacious than the older tricyclics, and their prescription costs are significantly higher, they provide superior effectiveness; ie, patients are less likely to discontinue taking them or switch antidepressants. Pharmacoeconomic studies consistently demonstrate a relationship between this superior effectiveness and reductions in overall treatment costs, often through decreased utilization of medical and hospital services. The most conservative study found a cost offset that more than negated the extra cost of drugs, although the cost savings were not statistically significant. Other studies found statistically significant lowering of utilization costs by using SSRIs rather than tricyclics. Studies comparing SSRIs with each other present conflicting findings, although fluoxetine appears to have an edge over sertraline and paroxetine with regards to effectiveness and pharmacoeconomics. More studies employing a prospective outcome design and naturalistic study setting need to be conducted with SSRIs and other new antidepressants.

Antidepressive Agents, Second-Generation↗
PubMed1996

Insulin internalization in the absence of the insulin receptor tyrosine kinase domain is insufficient for mediating intracellular biological effects.

The intracellular portion of the human insulin receptor (hIR) beta-subunit contains distinct functional domains including the exon 16-encoded juxtamembrane (JM) domain that mediates endocytosis, and the tyrosine kinase (TK) domain that mediates insulin's metabolic and mitogenic actions. To explore the functional relationship between these domains and to determine the role of insulin internalization in insulin action, we constructed and studied the endocytic and signaling properties of an hIR mutant truncated at Glu-1012. This truncation removes the carboxyl-terminal 343 amino acids containing essentially all of the TK domain but leaves behind the exon 16-encoded JM domain that is necessary for endocytosis, plus an additional 35 amino acids downstream. The wild-type (hIR-WT) and mutant (hIR delta 343) receptors were stably expressed in CHO cells and their abilities to mediate various insulin-stimulated functions were comparatively analyzed. In cells expressing hIR-WT, insulin markedly enhanced tyrosine phosphorylation of the beta-subunit and of the endogenous 185 kDa substrate whereas these effects were completely absent in cells expressing hIR delta 343. The hIR delta 343 receptors retained the ability to internalize a significant amount of surface-bound insulin at 37 degrees C. However, they were unable to mediate either the short or long-term biological effects of insulin as determined by assaying insulin-stimulated glucose uptake (assessed by 2-deoxyglucose uptake), protooncogene expression (measured by Northern blot analysis of c-fos mRNA) and DNA synthesis (measured by 3H-thymidine incorporation). These results indicate that the hIR beta-subunit JM and TK domains can be functionally uncoupled, and that insulin internalization in the absence of hIR TK domain and kinase activity is insufficient for mediating intracellular insulin action.

Animals↗
PubMed1996

Comparison of transrectal ultrasound prostatic volume estimation with magnetic resonance imaging volume estimation and surgical specimen weight in patients with benign prostatic hyperplasia.

There are relatively few reports in the literature comparing transrectal ultrasound (TRUS) to magnetic resonance imaging (MRI) in estimating the volume of the prostate in the management of benign prostatic hyperplasia (BPH). In this study, we compared volumes determined by TRUS with MRI and TRUS-estimated weights with surgical specimen weights. The main findings of this study were (a) TRUS and MRI measurement of prostate volumes are quite similar; and (b) TRUS underestimates (by 10%) the prostatic weight as determined from the surgical specimens. A better volume estimate can thus be obtained by multiplying the TRUS measurement by a factor of 1.10. We conclude that because TRUS is cheap, user-friendly, noninvasive, and equally as accurate as MRI, it should be the preferred modality in the follow-up of BPH patients.

Humans↗
PubMed1996

Methylation of the glial fibrillary acidic protein gene shows novel biphasic changes during brain development.

The gene for glial fibrillary acidic protein (GFAP) was analyzed in the rat for developmental changes in methylation of cytosine at CpG sequences as a correlate of the onset of GFAP mRNA expression and for the effect of methylation on GFAP promoter activity. The methylation of nine CpG sites in the GFAP promoter and ten sites in exon 1 was analyzed in F344 rats by a quantitative application of ligation-mediated polymerase chain reaction. Whole rat brain poly(A)+ RNA showed an exponential increase of GFAP mRNA after embryo day 14 that reached stable adult levels by postnatal day 10. During development, only the seven CpG sites in the far-upstream promoter showed large changes in methylation; these sites constitute the brain-specific domain of methylation described in adult rats (Teter et al: J Neurosci Res 39:680, 1994). These seven CpG sites showed a cycle of demethylation during the onset of GFAP transcription in the embryo (between embryonic day 14 and postnatal day 10) followed by remethylation at later postnatal ages when GFAP mRNA remains prevalent. The minimum levels of methylation across these CpG sites displayed a gradient with the lowest minima at the 3' sites. This demethylation/remethylation cycle is a novel phenomenon in DNA methylation during perinatal development. The demethylation/remethylation cycle during development was also shown by the opposite-strand cytosines. Two cytosines in this region that are conserved in rat and mouse also undergo the same demethylation/remethylation cycle in the mouse GFAP gene during development, implying evolutionary conservation and functional significance. As a further test of functional significance, a Luciferase reporter gene assay was evaluated in primary cultured astrocytes; the activity of the GFAP promoter was reduced when it was methylated at one or all CpG sites. Therefore, the GFAP promoter may be activated in rodent development by transient demethylation of a conserved brain-specific methylation domain.

Animals↗
PubMed1996

Effect of continuously warmed i.v. fluids on intraoperative hypothermia.

The investigators examined the effect of infusing continuously warmed (ie, 37.0 degrees C [98.6 degrees F]) i.v. fluids in two groups of middle-aged female patients undergoing laparoscopic cholecystectomy procedures. They hypothesized that increasing i.v. fluid temperature during surgery would decrease patients' risk for hypothermia. One group of patients received prewarmed i.v. fluids that cooled to room temperature during surgery. The second group received i.v. fluids that were warmed continuously by a fluid warmer during the surgical procedures. Analyses of covariance, with the first intraoperative temperature measurement treated as the covariate, revealed nonsignificant results at the P < .05 level. The results suggest that administering continuously warmed i.v. fluids intraoperatively has no significant effect on maintaining patients' body temperatures during short laparoscopic surgical procedures.

Adult↗
PubMed1996

A full genome search in multiple sclerosis.

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

Chromosome Mapping↗
PubMed1996

Advance directives: making them more available to hospitals patients.

This article details methods developed to facilitate patients' understanding and execution of an advance directive (e.g., living will, treatment preferences, and durable power of attorney for healthcare). The approach takes advantage of the computerization of patient records, using automatically generated e-mail messages sent to an advance directives consultation team.

Advance Directives↗
PubMed1996

Plasma exchange for dramatic gestational hyperlipidemic pancreatitis.

We describe the response to plasma exchange in a woman with extreme gestational hyperlipidemia and severe pancreatitis. Her serum triglyceride reached an astounding level of 21,300 mg/dl-among the highest concentrations ever recorded. Two consecutive plasma exchanges led to a remarkable reduction in triglyceride levels of 73% and 82%, respectively. Plasma viscosity decreased by 50% after the first plasma exchange. This was associated with an equally dramatic and unexpectedly rapid resolution of severe pancreatitis. Plasma exchange can rapidly and safely resolve extreme hyperlipidemia and be associated with prompt resolution of pancreatitis in women with severe gestational hyperlipidemic pancreatitis.

Acute Disease↗
PubMed1996

Blood pressure lowering in patients with cerebrovascular disease: results of the PROGRESS (Perindopril Protection Against Recurrent Stroke Study) pilot phase.

1. Among patients with cerebrovascular disease, there is a direct and continuous association between blood pressure and the risk of stroke, but previous trials of blood pressure lowering in this patient group have been inconclusive. 2. PROGRESS (Perindopril Protection Against Recurrent Stroke Study) is a multicentre, randomized, placebo-controlled trial that aims to determine reliably the effect of angiotensin converting enzyme (ACE) inhibitor-based blood pressure lowering on stroke risk in patients with a history of cerebrovascular disease. If a 4 week run-in period on active perindopril is well tolerated, participants are randomized to either perindopril (4 mg) +/- indapamide (2.5 mg) or matching placebo(s). The primary study outcome is stroke and follow-up is for a minimum of 4 years. 3. For the pilot study nearly 5000 medical records were screened and 60 patients with recent cerebrovascular events were approached directly in hospital or at a clinic visit. Sixty-seven patients entered the run-in phase (52 from retrospective screening and 15 by prospective approach) and 60 patients proceeded to randomization. Treatment with perindopril was well tolerated; only three patients were withdrawn due to side effects and four were withdrawn for other reasons. The mean age of randomized patients was 68 years; 70% were male and 55% were 'non-hypertensive'. The mean entry blood pressure was 142/83 mmHg and following pre-randomization treatment this was reduced by 7/4 mmHg. 4. Most patients were identified by retrospective review of medical records, but this was less efficient than prospective methods. Blood pressure lowering was well tolerated by both hypertensive and non-hypertensive patients with cerebrovascular disease. The small numbers of patients and the non-randomized nature of the data reported limit the conclusions that can be drawn, but the results confirm the feasibility of the main study.

Antihypertensive Agents↗
PubMed1996

Validation of the Short Form 36 (SF-36) health survey questionnaire among stroke patients.

BACKGROUND AND PURPOSE: Few studies have examined the utility of a new generic health status measure, the Short Form 36 health survey questionnaire (SF-36), in stroke patients. Our aim was to test the internal consistency and validity of the SF-36 in a cohort of long-term stroke survivors. METHODS: The Australian version of the SF-36 was tested in 90 consecutive 1-year stroke survivors (mean age, 72 years) identified from our hospital discharge data. The instrument was administered by personal interview. Validity was assessed by comparing patients' scores on the SF-36 with those obtained for the Barthel Index, the 28-item General Health Questionnaire, and the Adelaide Activities Profile, an instrument developed from the Frenchay Activities Index. RESULTS: The SF-36 was relatively quick and easy to use and had satisfactory internal consistency (Cronbach's alpha > 0.7). For all eight SF-36 health scales, the mean scores for patients dependent in self care and with mental ill health were significantly different from patients without these disabilities, but the strength of the differences varied in a predictable manner. However, the SF-36 social functioning scale did not provide a valid measure of everyday activities relevant to many elderly patients as measured by the Adelaide Activities Profile. CONCLUSIONS: The SF-36 avoids the "ceiling effect" of most disability scales and provides a valid measure of physical and mental health after stroke, but it does not appear to characterize well social functioning. Thus, the instrument may need to be supplemented by other measures for a comprehensive assessment of stroke outcome.

Adult↗
PubMed1996

Follow-up of renal and mesenteric artery revascularization with duplex ultrasonography.

OBJECTIVE: To evaluate the long-term results of renal revascularization procedures using duplex ultrasonography: DESIGN: A case series. SETTING: A university-affiliated hospital. PATIENTS: Twenty-five patients who had undergone renal percutaneous transluminal angioplasty (PTA) (18 arteries), renal bypass (10 arteries) and mesenteric bypass (6 arteries). The mean follow-up was 22 months (range from 3 to 48 months) for those who underwent renal PTA, 23 months (range from 1.5 to 70 months) for those who underwent renal bypass and 34 months (range from 8 to 144 months) for those who underwent mesenteric bypass. MAIN OUTCOME MEASURES: Patency rates for the three procedures as assessed by duplex ultrasonography. RESULTS: Duplex ultrasonography demonstrated patency without stenosis after renal and mesenteric artery revascularization in 14 arteries subjected to renal PTA, 9 arteries subjected to renal bypass and 6 arteries subjected to mesenteric bypass. Three arteries that had renal PTA had recurrent vessel stenosis and one had occlusion. One artery that had renal bypass showed occlusion. CONCLUSIONS: Renal PTA, renal bypass and mesenteric bypass are durable procedures at 2 years of follow-up, and duplex ultrasonography is a valuable method for assessing the patency of arteries after renal and mesenteric revascularization.

Angioplasty, Balloon↗
PubMed1996

Von Willebrand's disease in the Western Cape.

OBJECTIVE: To establish the prevalence of the various subtypes of Von Willebrand's disease (VWD) among patients with bleeding disorders in the Western Cape and to review appropriate treatment strategies. DESIGN: A systematic clinical and laboratory study. SETTING: Haemophilia clinics at two tertiary referral hospitals (Groote Schuur Hospital and Red Cross War Memorial Children's Hospital) in the Western Cape. PATIENTS: Twenty-two patients (14 females, 8 males; ages 3 - 55 years) were studied. Those studied were selected for reasons of convenience, as they were compliant and regular attenders at the clinics. MAIN OUTCOME MEASURES: History of a bleeding tendency; bleeding time measurements; factor VIII assays, von Willebrand factor (VWF) antigen assays; ristocetin co-factor assays and VWF multimer analysis. RESULTS: Fourteen patients had typical type I VWD; 2 had type II and 5 had type III variants, and there was 1 unclassifiable variant. Analysis of local factor VIII concentrates showed the presence of high-molecular-weight VWF multimers. CONCLUSION: The results are similar to patterns reported elsewhere in the world. Locally produced factor VIII concentrates, unlike a number of commercially produced concentrates, contain sufficient multimers for use as appropriate replacement therapy.

Adolescent↗