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Biomedical subjects

A Lo

Publications and source records attributed to A Lo.

At least 55 records · Page 3Linked to original sources
PubMed1999

Measurement of biodegradable substances using the salt-tolerant yeast Arxula adeninivorans for a microbial sensor immobilized with poly(carbamoyl)sulfonate (PCS). Part II: Application of the novel biosensor to real samples from coastal and island regions.

A microbial sensor for rapid measurement of the amount of biodegradable substances based on the salt-tolerant yeast Arxula adeninivorans LS3 has been developed especially for coastal and island regions. Our parameter, the so-called sensorBOD, that is available after only a few minutes, agrees with the 5-day value for the biochemical oxygen demand (BOD5) very well. We have employed the Arxula sensor in the short-time estimation and supervision of the BOD of both domestic and industrial wastewater with high salinity. The novel sensor makes it possible to monitor the different types of wastewater rapidly without pretreatment, and it can be used for an active process control of sewage treatment works. Compared to a commercially available sensor, the novel sensor achieves better agreement between sensorBOD and BOD5 measurements with salt containing samples.

Ascomycota↗
PubMed1999

Dialyzer performance in the clinic: comparison of six low-flux membranes.

The aim of this study is to assess the clinical performance of 6 different low-flux dialysis membranes under steady-state conditions in terms of urea and phosphate clearances. Ten stable hemodialysis patients were examined. The following dialyzers were studied, all in 1.5- to 1.6-m2 format: cuprammonium, cellulose acetate, cellulose diacetate, hemophane, polysulfone (low-flux), and polysynthane. The following parameters were examined: urea reduction ratio, phosphate reduction ratio, "instantaneous dialyzer clearance" for urea and phosphate, and total amount of urea and phosphate removed in the dialysate over a 1-week (three dialyses) period. Although there were differences between the membranes, all produced results within a narrow range. There was no one membrane that produced superior clearances in all categories. The cellulose acetate membrane was the least satisfactory membrane. Phosphate clearances were at best one third that of urea clearances. When choosing a low-flux dialysis membrane, urea and phosphate clearances are so similar amongst different membranes that other criteria are likely to have a greater influence on the choice of membrane.

Adult↗
PubMed1999

Validation of the Chinese-Cantonese version of the hospital anxiety and depression scale and comparison with the Hamilton Rating Scale of Depression.

OBJECTIVE: The aim of this study was to validate the Chinese-Cantonese version of the Hospital Anxiety and Depression Scale (HADS) and to compare it with the Hamilton Rating Scale of Depression (HRSD) as a screening tool for depressive disorders in general hospital in-patients. METHOD: The Chinese-Cantonese version of the HADS was administered to general hospital in-patients seen on a consultation basis, and psychiatric diagnoses were made according to DSM-III-R. The subjects were further rated independently with the HRSD. RESULTS: The Chinese-Cantonese version of the HADS was found to have good internal consistency and external validity, with favourable sensitivity and specificity for screening for psychiatric disorders. However, its performance was marginally inferior to that of the HRSD. The scale also performed poorly in identifying major depression. CONCLUSION: The HADS has limitations with regard to identification of depressive disorders. However, despite its shortcomings, it remains one of the best paper-and-pencil tests for screening psychiatric disorders in the medically ill.

Adult↗
PubMed1999

P-glycoprotein and drug therapy in organ transplantation.

The role of multidrug resistance and P-glycoprotein (P-gp) in the development of drug-resistant tumor cells has been extensively studied. As more knowledge on the physiological functions of P-gp has accumulated, the effects of P-gp modulation on the pharmacokinetics and the pharmacodynamics of many drugs have become apparent. Solid organ transplant recipients receive numerous medications that are substrates for P-gp. The objective of this review is to discuss the effects of P-gp modulation on the pharmacokinetics and the pharmacodynamics of immunosuppressive agents such as cyclosporine, tacrolimus, sirolimus, and corticosteroids. Pharmacokinetic alterations may occur in drug absorption since P-gp is in the small bowel, in drug distribution since P-gp functions in the blood-brain barrier, in drug metabolism since P-gp and cytochrome P450 3A have linked functions, and in drug elimination since P-gp is in the bile canaliculi and renal tubules. A link between P-gp and organ rejection has been speculated since upregulation of the P-gp pump may restrict immunosuppressant drug entry into immunocompetent cells. A further understanding of P-gp regulation upon chronic exposure to P-gp substrates and inhibitors and the potential administration of selective P-gp inhibitors will enhance our ability to use potent immunosuppressive drugs in organ transplant patients.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1999

Changing hepatitis A epidemiology among Hong Kong Chinese adolescents: what are the implications?

OBJECTIVE: To study the sero-epidemiology of hepatitis A virus (HAV) among adolescents in Hong Kong and analyse the changing patterns of the infection rates. DESIGN: Cross sectional study. SETTING: Secondary school students. SUBJECTS: One thousand, five hundred and eighty students were randomly selected from 12 schools in four regions of Hong Kong. MAIN OUTCOME MEASURES: Anti-HAV status. RESULTS: The overall prevalence of anti-HAV is 7%. The sero-prevalence for age group 11-20 y has fallen compared with 44.8% in 1978, 17.1% in 1987 and 11.2% in 1989. Those adolescents born in mainland China, who are frequent travellers and had a longer period of residence in mainland China were shown to have a higher prevalence of anti-HAV. CONCLUSION: The changing epidemiology of HAV indicates that Hong Kong will have a large proportion of susceptible young adults. Because of its geographic situation and import of most its food supplies from less developed countries, for epidemiological purposes the inhabitants can be compared to western travellers staying in a five star hotel in a less developed country. The risk of an outbreak of HAV is to be expected. Vaccination has the potential to serve as an effective prevention for adolescents living in countries whose circumstances are similar to Hong Kong.

Adolescent↗
PubMed1998

In vitro action of testosterone in potentiating gonadotropin-releasing hormone-stimulated gonadotropin-II secretion in goldfish pituitary cells: involvement of protein kinase C, calcium, and testosterone metabolites.

Overnight preincubation of goldfish pituitary cell culture with testosterone (T) enhanced the gonadotropin (GTH)-II responses to GTH-releasing hormone (GnRH). In this study, the involvement of GnRH signal transduction components and the requirement for T metabolism in mediating this direct, pituitary cell action of T were examined using cultured pituitary cells from both male and female goldfish. Each sets of related experiments were done in at least two different stages of the gonadal reproductive cycle and similar effects were observed. Overnight treatment with 10 nM T increased GTH-II responses to maximal stimulatory doses (100 nM) of either salmon (s)GnRH or chicken (c)GnRH-II, but not the total cellular GTH-II contents measured prior to and after a 2-h GnRH challenge. T increased the efficacy and sensitivity of the GTH-II response to stimulation by a protein kinase C (PKC) activator, tetradecanoyl phorbol acetate (TPA) without altering the ED50 of the dose-response curve. In T-treated cells, addition of a PKC inhibitor attenuated GTH-II responses to 100 nM doses of sGnRH, cGnRH-II, or TPA. T did not affect the GTH-II release stimulated by high concentrations of the Ca2+ ionophore ionomycin (100 microM) and the voltage-sensitive Ca2+ channel (VSCC) agonist Bay K 8644 (10 microM); similarly, the sensitivity of the GTH-II response to ionomycin and Bay K 8644 was also unaltered. Taken together, these data suggest that T potentiates GnRH-stimulated GTH-II release by enhancing the effectiveness of PKC-dependent pathways, but not by increasing the total Ca2+-sensitive GTH-II pool, the sensitivity of the release response to increases in intracellular Ca2+, or the amount of available GTH-II. However, the VSCC agonist nifedipine reduced sGnRH- and cGnRH-II-elicited GTH-II release in T-treated as well as in non-T-treated cells, suggesting that VSCC dependence is still present in the GnRH-induced response following exposure to T. Since total cGnRH-II binding to pituitary cells was not increased by T, increases in GnRH receptor capacity are unlikely following T treatment. The ability of T to increase GnRH-stimulated GTH-II secretion was not mimicked by 11-ketotestosterone or dihydrotestosterone, but was abolished by coincubation with an aromatase inhibitor. When viewed together, these observations suggest that aromatization of T may be required for the pituitary action of T on GnRH-induced GTH-II release.

Animals↗
PubMed1998

In vitro application of testosterone potentiates gonadotropin-releasing hormone-stimulated gonadotropin-II secretion from cultured goldfish pituitary cells.

The in vitro effects of overnight treatment with testosterone (T) on gonadotropin (GTH)-II secretion from primary cultures of dispersed female goldfish pituitary cells were examined. T (100 nM) did not affect basal GTH-II release, but increased GTH-II responses to initial applications of 0.5-h pulses of sGnRH or cGnRH-II in cells from females at sexually regressed, recrudescing, or mature (prespawning) stages. Pretreatment with 10 nM T was also effective, except in experiments with cells from sexually regressed females. Analysis of GTH-II response profiles to the first GnRH pulse revealed that T increased the size of the initial (first 15 min) and sustained (rest of response) release phases, and the duration of the total response to both GnRHs. These results indicate that direct positive influence of T on GnRH-stimulated GTH-II release is demonstrable in cells from female goldfish at all ovarian maturational stages; in addition, T affects both the initial and the sustained response phases. However, compared to the initial GnRH challenge, responses to a second 0.5-h GnRH pulse were decreased in T-treated but not in control cells, suggesting that T also enhanced desensitization. Ovarian maturational conditions modulated the effects of T on the GTH-II response kinetics. In cells prepared from sexually regressed females, T treatment changed the "monophasic" (initial phase only) GTH-II response to sGnRH to a "biphasic" one characteristic of cells prepared from fish at later stages of gonadal recrudescence. Advancing gonadal maturity increased the magnitude of both initial and sustained phases of the T-enhanced GTH-II response to sGnRH, but only elevated the initial phase of T-potentiated cGnRH-II-induced release. Direct actions of T on pituitary cells may play a role in ovarian steroid feedback regulation of GTH-II secretion during the seasonal reproductive cycle in goldfish.

Animals↗
PubMed1998

Renal disease in Down syndrome: autopsy study with emphasis on glomerular lesions.

A range of renal diseases have been previously described in patients with Down syndrome. With increased survival, it appears that a growing number of these patients present with chronic renal failure. Definition of underlying causes of renal failure could potentially lead to prevention of progressive renal dysfunction in this population. We report two index cases of teenaged Down patients who presented with proteinuria and focal segmental glomerulosclerosis with hyalinosis, not previously described in this population. In addition, autopsy files were reviewed at the Johns Hopkins Hospital to assess renal and especially glomerular pathology in Down patients. Additional cases, including acute glomerulonephritis with early crescents and vasculitis, minimal change disease, and membranous nephropathy, were identified; the latter two diseases had not been previously reported in patients with Down syndrome. Semiquantitative studies on glomerular changes in all cases examined through autopsy also were performed. The only pathological finding that was significantly more common in the Down syndrome group, compared with age-matched cases from the autopsy files, was cystic dilation of Bowman's space. Histological findings described as increased in the Down population in previously published autopsy studies were also present in the control population, highlighting the need to adequately control such studies. The cases of acquired glomerular disease reported here were seen largely after the first decade of life. Monitoring of Down patients for renal and especially glomerular disease should be done regularly as patients age into the second and third decades.

Adolescent↗
PubMed1998

Possible adverse skin reaction to carvedilol.

As experience with beta-blocker use in patients with congestive heart failure is increasing, enthusiasm for carvedilol use in these patients is also increasing. Dermatological reactions to carvedilol are rare and have not been well described in the literature. A patient who developed an acute dermatological reaction after one dose of 3.125 mg carvedilol is presented. Given the rapid onset of symptoms experienced by the patient after a single, small dose of carvedilol, clinicians should be aware of the potential adverse effects of the drug.

Adrenergic beta-Antagonists↗
PubMed1997

Estimates of infectious disease risk factors in US blood donors. Retrovirus Epidemiology Donor Study.

OBJECTIVE: Individuals who do not respond accurately to questions about infectious disease risk factors at the time of blood donation represent a potential threat to the safety of the blood supply. This study was designed to estimate the prevalence of undetected behavioral and other risks in current blood donors. DESIGN: Anonymous mail surveys to collect demographic, medical, and behavioral information were administered to individuals who had donated blood within the previous 2 months. Sampling weights were used in the analysis to adjust for differential sampling and response rates among demographic groups to provide prevalence estimates for the donor population. SETTING: Five geographically and demographically diverse US blood centers. PARTICIPANTS: A stratified probability sample of 50,162 allogeneic blood donors. MAIN OUTCOME MEASURES: Estimated prevalence rates for risk behaviors that would have been a basis for deferral if reported at the time of the donor screening interview (deferrable risk). RESULTS: Completed questionnaires were received for 34,726 donors (69.2% of the sample). A total of 186 per 10,000 respondents (1.9%) reported a deferrable risk that was present at the time of their past donation, while 39 per 10,000 (0.4%) reported this behavior within the 3 months prior to donation. Rates (with 95% confidence intervals [CIs]) of deferrable risk behaviors were 1.4 (95% CI, 1.2-1.6) times higher for men than women, 1.6 (95% CI, 1.3-2.0) times higher for first-time vs repeat donors, 2.7 (95% CI, 2.0-3.6) times higher for donors with reactive screening tests, and 7.6 (95% CI, 3.6-15.8) times higher for donors who used the confidential unit exclusion option. CONCLUSIONS: Despite the high degree of transfusion safety in the United States today, a measurable percentage of active blood donors when assessed by anonymous survey report risks for human immunodeficiency virus and other infections not reported at the time of screening, suggesting the need for further refinements in the blood donor qualification process.

Blood Banks↗
PubMed1996

Retrograde ascending aortic dissection diagnosed by intraoperative transesophageal echocardiography.

Aortic dissection is a risky but challenging cardiovascular emergency and rapid surgical intervention for life-saving is sometimes inevitable. For detection of aortic dissection, computed tomography, magnetic resonance imaging, aortography all have their advantages but all have their limitations. Transesophageal echocardiography (TEE), which is portable and relatively noninvasive, is a highly sensitive and specific diagnostic tool for evaluation of aortic diseases. We presented a case in which preoperative imaging studies such as MRI and cardiac catheterization were all suggestive of DeBakey's type I aortic dissection. However, it was further proved to be a retrograde ascending aortic dissection during intraoperative TEE imaging study as a retrograde ascending blood flow was demonstrated within the dissected aortic lumen. So the initial operative scheme was changed and sternothoracoabdominal incision was selected for better exposure for one-stage repair of the entire thoracic aorta. Nevertheless, severe intrathoracic adhesion and case to bleed prevented any aggressive intervention to proceed. The operation was called off and the patient was transferred to ICU for further medical treatment.

Aged↗
PubMed1995

Widespread expression of Huntington's disease gene (IT15) protein product.

Huntington's Disease (HD) is caused by expansion of a CAG repeat within a putative open reading frame of a recently identified gene, IT15. We have examined the expression of the gene's protein product using antibodies developed against the N-terminus and an internal epitope. Both antisera recognize a 350 kDa protein, the predicted size, indicating that the CAG repeat is translated into polyglutamine. The HD protein product is widely expressed, most highly in neurons in the brain. There is no enrichment in the striatum, the site of greatest pathology in HD. Within neurons, the protein is diminished in nuclei and mitochondria and is present in the soluble cytoplasmic compartment, as well as loosely associated with membranes or cytoskeleton, in cell bodies, dendrites, and axons. It is concentrated in nerve terminals, including terminals within the caudate and putamen. Thus, the normal HD gene product may be involved in common intracellular functions, and possibly in regulation of nerve terminal function. The product of the expanded allele is expressed, consistent with a gain of function mechanism for HD at the protein level.

Amino Acid Sequence↗
PubMed1995

Sustained attention training for unilateral neglect: theoretical and rehabilitation implications.

Many studies have shown a co-variation of unilateral neglect with nonlateralised attentional functions. Recently, Posner has argued that there are two separate neural systems that influence the posterior attentional system which is presumed to be impaired in unilateral neglect, namely, the posterior system itself (located partly in the inferior parietal lobules) as well as a secondary modulatory sustained attention or vigilance system. This latter system is linked to the nor-epinephrine system, which is known to be more strongly represented in the right compared to the left hemisphere of the brain. If this hypothesis is true, then unilateral neglect should be improved by increasing activation of the sustained attention system. Eight patients suffering from chronic left unilateral neglect were trained to sustain their attention by a self-alerting procedure partially derived from Meichenbaum's self-instructional methods. Using a multiple-baseline-by-function design, as well as multiple-baseline-by-subject designs, statistically significant improvements in unilateral neglect as well in sustained attention were found following onset of sustained attention training, without corresponding improvements in control measures. Theoretical implications for the attentional underpinnings of unilateral neglect are discussed, as well as the rehabilitation implications of this training procedure.

Aged↗
PubMed1994

The adequacy of fragmin as a single bolus dose with reused dialyzers.

Thirty-four hemodialysis patients were studied in a crossover fashion to compare the effectiveness of bolus-dose Fragmin (a low molecular weight heparin) with regular heparin usage in hemodialysis. For each anticoagulant, 3 dialyzes were studied for each patient; the first sessions involved a new dialyzer, and the subsequent sessions involved dialyzers reprocessed with peracetic acid. To assess the effectiveness of the anticoagulation regimens, the following were measured: the dialyzer fiber bundle volume and the instantaneous dialyzer clearances for urea (1 h into the second session). In addition, factor Xa levels were measured in 5 patients during the first and second sessions at 0 min, 30 min, and 4 h. Fiber bundle volumes were (in ml) 75.4 +/- 8.8, 73.0 +/- 8.9, and 73.5 +/- 7.6 on first, second, and third uses with Fragmin (p = ns); and 77.8 +/- 9.0, 73.4 +/- 8.1, and 73.8 +/- 8.1 with heparin (p < 0.001 second and third vs. first). Thus, there were no significant differences between Fragmin and heparin. Instantaneous dialyzer clearances were 165.8 +/- 12.6 ml/min with Fragmin and 163.8 +/- 9.8 with heparin (p = ns). Factor Xa levels were 0 predialysis, 0.81 +/- 0.17 U/ml at 30 min on first use, and 0.92 +/- 0.09 U/ml on second use (p = ns); they were 0.51 +/- 0.21 U/ml at 4 h on first use and 0.61 +/- 0.16 U/ml on second use (p = ns). Thus, bolus-dose Fragmin provided similar results to constant infusion heparin and is not deleteriously influenced by reprocessing dialyzers with peracetic acid.

Adult↗
PubMed1993

An evaluation of freestanding alcoholism treatment for Medicare recipients.

The Health Care Financing Administration (HCFA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) conducted a demonstration between 1982 and 1985 to test the feasibility of providing payments for alcoholism treatment services to Medicare and Medicaid recipients in specially selected freestanding facilities. This study of the Medicare part of the demonstration answers two questions: do freestanding facilities save money for Medicare and do their patients have lower health care utilization following initiation of treatment than patients treated in hospital-based facilities? The statistical methodology is a logit and cluster approach. The analysis begins with a logistic regression model to predict the probability of patients seeking alcoholism treatment in either the demonstration (freestanding facility) or hospital-based cohort. The statistically significant variables from logit analysis are then used to form clusters. The health expenditures of freestanding and hospital patients are compared within homogeneous clusters. This study shows that the number of admissions, the average length of stay, and the average monthly health expenditures following the start of treatment are lower for the group treated in the freestanding facilities. The conclusion is that for some persons with alcohol problems, treatment in freestanding facilities is less costly and leads to lower subsequent health care utilization than treatment in hospitals.

Adult↗
PubMed1990

[Branches of the vertebral artery to the spinal cord].

On the cervical level, ramifications stemming directly from the vertebral artery are studied while nevertheless taking into account contributions from rising and deep cervical, and while sometimes even from the upper intercostal and/or the occipital, as well as anastomoses contracted from these various sources at the level of the neck. No bulging cervical artery exists, but the variations observed are frequent. Pedicles are rarely symmetrical and usually alternate between left and right sides. Two, differently coloured injections sometimes reveal a preponderance for one side rather than the other, but the injections must be able to be made at the same time and with an equal degree of precision if a formal conclusion is to be drawn from this.

Adult↗