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Biomedical subjects

A Fish

Publications and source records attributed to A Fish.

At least 19 recordsLinked to original sources
PubMed2003

Impact of protocol-based guidelines on the management and outcome of acute upper gastrointestinal hemorrhage in a district general hospital.

A prospective audit of acute upper gastrointestinal (GI) hemorrhage was conducted between January and September 2000 at Frimley Park Hospital to determine the impact of introducing an upper GI bleeding protocol based on Rockall's initial risk scoring system. Fifty-seven patients and 52 patients were in the pre- and postprotocol phases of the study respectively. Fifty per cent (28) of the patients in the first phase and 40% (21) of the patients in the second phase belonged to the high risk group. In the preprotocol phase, endoscopy was performed in 86% (49) of cases with 60% of patients having an esophogastroduodenoscopy within 24 h. Thirty-three per cent of the high risk group failed to have an endoscopic examination within 24 h. Only two of 57 patients required surgery and the mortality was 14%. In the postprotocol phase, endoscopy was performed in 79% (42) of patients and 68% (36) patients had endoscopy within 24 h. Only four of 21 patients belonging to the high risk group had their endoscopy after 24 h of the admission. Patients were better monitored and mortality was reduced to 7.5%. Reduction of mortality from upper GI hemorrhage followed the introduction of an agreed protocol based on risk scoring.

Adolescent↗
PubMed2001

The assembly of the PsaD subunit into the membranal photosystem I complex occurs via an exchange mechanism.

PsaD is a peripheral stromal-facing subunit of photosystem I (PSI), a multisubunit complex of the thylakoid membranes. PsaD plays a major role in both the function and assembly of PSI. Past studies with radiolabeled PsaD indicated that PsaD is able to assemble in vitro specifically into the PSI complex. To unravel the mechanism by which this assembly takes place, the following steps were taken. (i) Mature PsaD of spinach and PsaD of the prokaryotic caynobacterium Mastigocladus laminosus, both bearing a six-histidine tag at their C-termini, were overexpressed in Escherichia coli and purified to homogeneity. (ii) The purified recombinant protein was introduced into the isolated PSI complex. (iii) Following incubation, the PsaD that assembled into PSI was separated from the nonassembled PsaD by a sucrose gradient. Differential Western blot analysis was used to determine whether the native and the recombinant PsaD were present as free or assembled proteins of the PSI complex. Antibodies that can recognize only the recombinant PsaD (anti-his) or both the native and recombinant PsaD (anti-PsaD) were used. The findings indicated that an exchange mechanism enables the assembly of a newly introduced PsaD into PSI. The latter replaces the PsaD subunit that is present in situ within the complex. In vivo studies that followed the assembly of PsaD in Chlamydomonas reinhardtii cells supported this in vitro-characterized exchange mechanism. In C. reinhardtii, in the absence of synthesis and assembly of new PSI complexes, newly synthesized PsaD assembled into pre-existing PSI complexes.

Animals↗
PubMed2000

An insight into the assembly and organization of photosystem I complex in the thylakoid membranes of the thermophilic cyanobacterium, Mastigocladus laminosus.

The present study characterizes the assembly and organization of Photosystem I (PSI) complex, and its individual subunits into the thylakoid membranes of the thermophilic cyanobacterium, Mastigocladus laminosus. PSI is a multiprotein complex that contains peripheral as well as integral subunits. Hence, it serves as a suitable model system for understanding the formation and organization of membrane protein complexes. In the present study, two peripheral cytosol facing subunits of PSI, namely, PsaD and PsaE were overexpressed in E. coli and used for assembly studies. The gene encoding PsaK, an integral membrane spanning subunit of PSI, was cloned and the deduced amino acid sequence revealed PsaK to have two transmembrane alpha-helices. The characterization of the in vitro assembly of the peripheral subunits, PsaD and PsaE, as well as of the integral subunit, PsaK, was performed by incubating each subunit with thylakoids isolated from Mastigocladus laminosus. All three subunits studied were found to assemble into the thylakoids in a spontaneous mechanism, showing no requirement for cytosolic factors or NTP's (nucleotide 5'-triphosphate). Nevertheless, further characterization of the assembly of PsaK revealed its membrane integration to be most efficient at 55 degrees C. The associations and protein-protein interactions between different subunits within the assembled PSI complex were directly quantified by measurements performed using the BIACORE technology. The preliminary results indicated the existence of specific interaction between PsaD and PsaE, and revealed a very high binding affinity between PsaD and the PSI electron acceptor ferridoxin (Kd = 5.8 x 10(-11) M). PsaE has exhibited a much lower binding affinity for ferridoxin (Kd = 3.1 x 10(-5) M), thereby supporting the possibility of PsaE being one of the subunits responsible for the dissociation of ferridoxin from the PSI complex.

Amino Acid Sequence↗
PubMed1999

A 5-year follow up of mildly dyskaryotic smears, comparing colposcopy with expectant management.

The purpose of this study was to see if the National Health Service Cervical Screening Programme's guidelines were appropriate when they recommended that mildly dyskaryotic smears were repeated before referral for colposcopy. We identified all those with a mildly dyskaryotic smear, and followed them over 5 years, to compare those that had colposcopy and those that did not. In total, 269 women were followed and 35% of these only had the one mild smear. Of those whose smear returned to normal after the initial mild smear, 84% remained normal over the 5-year period. Of those whose smear did not return to normal, i.e. those that required a colposcopy, 74% returned to normal after the colposcopy.

Journal Article↗
PubMed1993

The adnexal mass: benign or malignant? Evaluation of a risk of malignancy index.

OBJECTIVE: To validate a risk of malignancy index incorporating menopausal status, serum CA 125 level and pelvic ultrasound features in the pre-operative diagnosis of ovarian cancer. DESIGN: A retrospective observational study. SETTING: Department of Obstetrics and Gynaecology, The Royal London Hospital. SUBJECTS: One hundred and twenty-four women admitted consecutively to the gynaecology department for surgical exploration of an adnexal mass. MAIN OUTCOME MEASURES: The sensitivities and specificities of menopausal status, serum CA 125 level and ultrasound features, in isolation and combined (the risk of malignancy index (RMI)), for diagnosing ovarian cancer. RESULTS: Tested on a new population of women, the RMI retained the high sensitivity for diagnosing ovarian cancer seen in the original report describing its derivation. The specificity, however, was lower. The study confirmed that the RMI is more accurate than the individual criteria in diagnosing ovarian cancer, and was comparable with other scoring systems. CONCLUSIONS: The risk of malignancy index is a simple scoring system for ovarian cancer. Application of the risk of malignancy index in clinical practice may provide a rational basis for specialist referral of patients with ovarian cancer before diagnostic surgery.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1988

[Multicenter double-blind study comparing astemizole and terfenadine for nonseasonal rhinitis in the adult].

This comparative multicentric randomized study was carried out by 36 town allergists, during 2 months out of pollen season, following the double blind rigorous methodology. It concerns 109 patients, about 30 years old, and suffering from allergic and aperiodic rhinitis, since 6 to 7 years on an average. After a period of 2 months the treatment was considered to be sufficiently effective in 77.7% of the patients treated with Astemizole; and in 65.2% of those treated with Terfenadine. We remark, as much in the study about the global efficacy as in the symptom by symptom study, a superiority of the Astemizole on the Terfenadine. This difference in effectiveness repeatedly reaches a significant level, at the time of the daily evaluation of symptoms. The action time is equivalent in both groups. The observed lateral effects are minor, and they differ between both groups, neither in frequency nor in nature. The new HI anti-histaminics are characterized by the absence of sedative effect and by their good tolerance. This study demonstrates their effectiveness and their action rapidity, in a chronic pathology that is specially constraining for the patient.

Adult↗
PubMed1984

Idiopathic hypercalciuria associated with hyperreninemia and high urinary prostaglandin E.

A patient with idiopathic hypercalciuria and some features suggestive of Bartter syndrome is reported. Excessive urinary prostaglandin E (PGE) excretion and renal calcium leak were documented in this child. Treatment with aspirin and indomethacin reduced urinary PGE excretion and was associated with a decrease in daily calcium excretion. At the lowest levels of urinary PGE, the renal calcium leak was no longer evident although mild hypercalciuria persisted. These results suggest that PGE may play a role in some cases of idiopathic hypercalciuria.

Aspirin↗
PubMed1983

Effects of intravenous epoprostenol on platelets and the cardiovascular system are not potentiated by dipyridamole.

Normal subjects received infusions of epoprostenol (prostacyclin, PGI2) at doses of 2, 4, 6, and 8 ng/kg/min on each of two occasions after pretreatment with dipyridamole (400 mg/day for 3 days) or placebo. Baseline headache and bleeding time were increased and preejection period (PEP) shortened after dipyridamole. The baseline heart rate was increased on dipyridamole by an amount that correlated to the blood dipyridamole level. PGI2 infusion increased heart rate, systolic blood pressure (BP), pulse pressure, left ventricular ejection time index, and degree of flushing and severity of headache, and reduced diastolic BP, PEP, and T wave height. There was no apparent interaction between PGI2 and dipyridamole on these variables. PGI2 inhibited adenosine diphosphate-induced platelet aggregation and increased bleeding time. We conclude that, despite the synergism between dipyridamole and PGI2 that might be predicted and has been demonstrated in some animal experiments, no such interaction is apparent in normal humans after standard doses.

Adult↗
PubMed1982

The cardiovascular and platelet effects of epoprostenol (prostacyclin, PGI2) are unaffected by beta-adrenoceptor blockade in man.

1 Atenolol 0.2 mg/kg i.v., propranolol 0.2 mg/kg i.v. or placebo were given in a double-blind crossover study to six healthy male subjects, and the effects of a subsequent infusion of epoprostenol (prostacyclin, PGI2) 0-6 ng kg-1 min-1 monitored. 2 PGI2 caused a tachycardia, a fall in diastolic blood pressure, a rise in pulse pressure, reduction in pre-ejection period (PEP) and rise in left ventricular ejection time index (LVETI), headache and facial flushing at doses of PGI2 greater than 2 ng kg-1 min-1,, (P less than 0.05). 3 Beta-adrenoceptor blockade did not prevent the tachycardia in response to PGI2, and did not interact with any of the other dynamic effects of PGI2. 4 In vitro, PGI2 at 1 and 2 ng/ml inhibited platelet aggregation to ADP (P less than 0.01), although no significant effect on platelet aggregation was seen in the in vivo study. Atenolol and propranolol at a final concentration of 1 microgram/ml did not affect this in vitro study. Atenolol and propranolol at a final concentration of 1 microgram/ml did not affect in vitro effect of PGI2 on platelet aggregation. 5 Pretreatment with atropine 0.04 mg/kg i.v. in three subjects did not attenuate the tachycardia caused by PGI2 infusion, even though the baseline heart rate was increased. 6 Adverse effects to PGI2 infusion included sudden bradycardia, pallor and sweating, suggesting that the Bezold-Jarisch reflex seen in animals in response to PGI2 may also occur in humans. 7 Neither increased sympathetic drive nor vagal withdrawal are likely causes of the tachycardia following PGI2 infusion.

Adrenergic beta-Antagonists↗
PubMed1981

Propranolol and sotalol as antagonists of isoproterenol-enhanced physiologic tremor.

Six normal subjects were studied after graded bolus injections of isoproterenol. Log dose-response curves for increases in both heart rate (mostly beta 1), and amplitude of physiologic tremor (beta 2) were constructed for each subject in the control state and 2 hr after 10 or 40 mg propranolol, 200 mg sotalol, or placebo. All heart rate curves were shifted to the right in an approximately parallel fashion by all active treatments (40 mg propranolol greater than 200 mg sotalol greater than 10 mg propranolol). The tremor curve was also shifted to the right by 10 mg propranolol in an approximately parallel fashion and to the same extent as the heart rate curve (both dose-ratios = 6.1), but the tremor curves after both 40 mg propranolol and 200 mg sotalol appeared to be flattened as well as shifted laterally. We conclude that whereas it may be possible that 10 mg propranolol acts as a competitive antagonist of isoproterenol at beta 2-sites in skeletal muscle, 40 mg propranolol and 200 mg sotalol must have additional actions in reducing isoproterenol tremor. The possibilities are discussed.

Administration, Oral↗
PubMed1976

Some observations on the epidemiology of toxoplasmosis in Canada.

Between 1961 and 1974, 11934 samples of serum were tested by the Sabin-Feldman Dye test for the presence of antibodies to Toxoplasma gondii. Analysis of high-titred sera suggested that a 6-year cycle of high disease prevalence occurred across Canada. In addition, a decline in the percentage of positive reactions each year in the Fall. The suggestion that this decline was due to dry conditions during the summer months was supported by the observation that differences in the prevalence of toxoplasma infection in ten Canadian cities were related to their average summer rainfall. The significance of these observations in relation to the epidemiology of toxoplasmosis in this country is discussed. The influence of patient age on the prevalence of infection was also investigated; the results obtained suggested that at least 75% of infants with high antibody titres against T. gondii had obtained these antibodies by placental transfer from their mothers.

Adolescent↗