Search PubMed⌕ Search

Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 325 records · Page 18Linked to original sources
PubMed1996

Identification of the gene encoding DNA topoisomerase I from Candida albicans.

A gene encoding a type I topoisomerase (TOP1) was isolated from Candida albicans, sequenced, and expressed in Saccharomyces cerevisiae. The TOP1 gene was identified from a C. albicans genomic library by hybridization with the product of a polymerase chain reaction with degenerate primer sets encoding regions conserved in other TOP1 genes. A clone containing an open reading frame of 2463 bp and predicted to encode a protein of 778 amino acids with sequence similarity to eukaryotic type I topoisomerases was identified. The C. albicans TOP1 gene restored camptothecin sensitivity and increased the topoisomerase activity in S. cerevisiae, indicating that the DNA fragment encodes a functional C. albicans topoisomerase I.

Amino Acid Sequence↗
PubMed1996

Urinary phenylethylamine and cortisol levels in the early puerperium.

Phenylethylamine and cortisol were measured in 24-h urine samples taken from women day 2/3 postpartum, and matched controls. They also completed self-rating blues and highs scales. There was no significant difference in phenylethylamine excretion in those who scored highly with blues or highs, and either postpartum or normal controls. The number of raised values for phenylethylamine output was significantly greater in the postpartum women, who had no psychopathology, than in normal controls. Cortisol levels were significantly raised in postpartum controls compared with normal controls; women with the highs excreted significantly less cortisol than other postpartum women.

Adolescent↗
PubMed1996

The Rz1 gene product of bacteriophage lambda is a lipoprotein localized in the outer membrane of Escherichia coli.

The Rz1 gene of bacteriophage lambda is located within the Rz1 lysis gene. It codes for the 6.5-kDa prolipoprotein (Rz1) which undergoes N-terminal signal sequence cleavage and post-translational lipid modification of the N-terminal Cys of the mature protein. Globomycin, the antibiotic which inhibits bacterial signal peptidase II, specific for prolipoproteins containing diacylglyceryl cysteine [Hayashi and Wu, J. Bioenerg. Biomembr. 22 (1990) 451-471] inhibits the N-terminal sequence cleavage of the Rz1 precursor. The mature protein is rich in Pro, which constitutes 25% of its amino acids (aa). Using a computer-predicted, synthetic, 15-aa antigenic determinant of Rz1 polyclonal anti-Rz[46-60] antibodies, were obtained, and employed to localize Rz1 in bacterial fractions. In induced Escherichia coli lambda lysogens Rz1 was found almost exclusively in the outer membrane (OM). In a strain overproducing Rz1 from the pSB54 plasmid, it was distributed in all the fractions, OM, fraction A and inner membrane (IM). Expression of Rz1 from the pSB54 caused enlargement of fraction A, corresponding to the adhesion sites of OM and IM. Such an enlargement was previously observed in induced lambda lysogens, shortly before the onset of lysis.

Amino Acid Sequence↗
PubMed1996

Effect of a dynein inhibitor on vasopressin action in toad urinary bladder.

1. The effect of the dynein inhibitor erythro-9-[3-(2-hydroxynonyl)] adenine (EHNA) on the osmotic water flow response to vasopressin or exogenous cAMP has been investigated in isolated toad urinary bladders. 2. Pretreatment with serosal EHNA had no effect on basal water flow, but inhibited the development and maintenance of the hydrosmotic response to vasopressin (20 mU ml-1) or 8-(4-parachlorophenylthio)-adenosine 3',5'-cyclic monophosphate (8 CPT-cAMP; 0.1 mM). 3. The inhibitory effect of EHNA on vasopressin-induced water flow was dose dependent. Inhibition occurred in the dose range in which EHNA inhibits the ATPase and motor activities of dynein in vitro. 4. EHNA also inhibited the maintenance of the high rate of water flow established by prior exposure to vasopressin. 5. The inhibitory effect of EHNA on the onset phase of the vasopressin response was attenuated after exposure of the tissue to the microtubule-disruptive drug nocodazole but was fully additive with that of cytochalasin B. 6. EHNA inhibited basal and vasopressin-stimulated transepithelial sodium transport. 7. The findings support the view that EHNA inhibits hormone-induced water flow through an action on a cytoplasmic dynein. The results are consistent with the hypothesis that dynein is involved in the microtubule-based delivery of water channel-containing vesicles to the apical membrane of the granular epithelial cells during both the onset and maintenance of the water permeability response to vasopressin.

Adenine↗
PubMed1996

Differentiated vascular myocytes: are they involved in neointimal formation?

The role of differentiated vascular myocytes are neointimal formation in canine carotid artery was investigated. Using antibodies and cDNA probes, cells were characterized in situ and after isolation. In situ characterization indicated the majority of medial cells expressed both smooth muscle myosin and alpha actin but many cells were negative to these markers. All adventitial cells were negative for these proteins. The muscle protein-positive cells were designated differentiated, vascular myocytes (VSMC). The others were designated type 2 cells. Sequential enzyme digestion from lumenal surface yielded VSMC ( > 90%) while digestions from the adventitial surface yielded type 2 cells ( > 90%). VSMC were viable in culture but did not spread, proliferate, or alter expression of muscle proteins. Type 2 cells proliferated and increased their expression of muscle actin but did not express muscle myosin. Characterization of neointimal cells from injured carotid arteries indicated they were morphologically and immunologically identical to cultured type 2 cells. We concluded that: (a) canine carotid artery media consists of a heterogeneous cell population: (b) serum does not stimulate isolated VSMC to undergo phenotypic modulation or proliferate: and (c) type 2 cells may be responsible for neointimal formation because they proliferate and acquire a phenotype identical to in situ neointimal cells.

Actins↗
PubMed1996

Biochemistry of tellurium.

Tellurium (Te) demonstrates properties similar to those of elements known to be toxic to humans, and has applications in industrial processes, which are rapidly growing in importance and scale. It is relevant, therefore, to consider the tellurium physiology, toxicity, and methods for monitoring the element in biological and environmental specimens. Animal studies suggest that up to 25% of orally administered tellurium is absorbed in the gut. There is a biphasic elimination from the circulation with loss of about 50% within a short period, t1/2 = 0.81 d, and slower elimination of the residual Te, t1/2 = 12.9 d. Following a single ip, injection the largest proportion is in the kidney and bone, but with repeated oral administration, Te is found in the heart > > kidney, spleen, bone, and lung. Formation of dimethyl telluride is a characteristic feature of exposure, and gives a pungent garlic-like odor to breath, excreta, and the viscera. The main target sites for Te toxicity are the kidney, nervous system, skin, and the fetus (hydrocephalus). Te can be reliable measured in different specimens by several analytical techniques. Recent work has employed hydride generation atomic absorption spectrometry. Topics for further investigation are proposed.

Administration, Oral↗
PubMed1996

IbpA and IbpB, the new heat-shock proteins, bind to endogenous Escherichia coli proteins aggregated intracellularly by heat shock.

IbpA/B, 16 kDa heat-shock proteins were recently described as recognizing heterologous protein inclusion bodies in Escherichia coli cells; the corresponding genes formed an operon regulated by the rpoH gene product, sigma 32 protein (Burland et al (1993) Genomics 16, 551; Allen et al (1992) J Bacteriol 174, 6938; Chuang et al (1993) Gene 134, 1; Chuang and Blattner (1993) J Bacteriol 175, 5242). We have found that IbpA/Bs also recognize endogenous bacterial proteins aggregated intracellularly by heat shock. IbpA/B proteins were isolated and purified from the aggregates (the S fraction), identified by amino acid microsequencing and used as immunogen for anti-IbpA/B serum preparation. Western blotting with the serum showed that in cells growing at 30 degrees C IbpA/B were located in the bacterial outer membrane and appeared in the S fraction after heat shock. Then the cellular level of the IbpA/B proteins increased about 20-fold as estimated by densitometry of the Western blots. In the E coli rpoH strain the level of IbpA/B was higher than in wild type before the heat shock and rose to still higher levels after it. This result pointed to a regulation of ibpA/B operon by another factor, besides that of sigma 32.

Bacterial Proteins↗
PubMed1996

The importance of work-up (verification) bias correction in assessing the accuracy of SPECT thallium-201 testing for the diagnosis of coronary artery disease.

Noninvasive testing is often evaluated by the sensitivity and specificity in comparison with a more invasive, but more definitive "gold" standard. However, work-up or verification bias, which occurs when the results of a noninvasive test impact the decision to perform the gold standard invasive test, increases the "observed" sensitivity and decreases the "observed" specificity of the noninvasive test. Most large clinical studies utilizing a noninvasive technique to diagnose coronary artery disease have biases, particularly work-up bias. To obtain more accurate measurements of sensitivity and specificity, we determined the observed sensitivity and specificity of stress (exercise and dipyridamole) single photon emission computed tomographic (SPECT) thallium testing for the detection of coronary artery disease by angiography, and then applied previously published equations to correct for work-up bias. From a computerized data base, reports of 4354 stress SPECT thallium studies from January 1, 1986 through December 31, 1992 were reviewed. All patients with a known history of myocardial infarction or prior coronary angiography were excluded, leaving 2688 patients. From this total, 471 patients underwent coronary angiography within 90 days following stress SPECT thallium testing. Coronary artery disease was defined as a visually assessed stenosis of a coronary artery or a major branch > 50%. Of the 2688 stress SPECT thallium studies, 1265 were normal and 1423 were abnormal. For the 471 patients who underwent catheterization within 90 days following stress SPECT thallium testing. the "observed" sensitivity and specificity were 98 and 14%, respectively. After correction for work-up bias, the corrected sensitivity and specificity were 82 +/- 6% and 59 +/- 2%, respectively. Most studies utilizing noninvasive technologies for the detection of coronary artery disease include patients with known coronary artery disease and have work-up bias as well. By knowing the thallium results of patients with and without catheterization, we were able to correct for work-up bias. These data provide better estimate of the sensitivity and specificity of stress SPECT thallium testing.

Bias↗
PubMed1996

Radiation risk to the urologist during endourologic procedures, and a new shield that reduces exposure.

OBJECTIVES: With the increasing use of endourologic procedures to diagnose and treat urologic problems, the urologist's exposure to radiation from fluoroscopy becomes an important safety consideration. Although collimation of the x-ray beam generally prevents direct radiation exposure by the urologist, the patient absorbs radiation during the procedure and becomes a secondary source of exposure through radiation scatter. METHODS: We measured radiation exposure to the urologist during endourologic procedures using standard body shields and thyroid collars. We repeated our surveys using a newly designed urologic surgery radiation shield. RESULTS: We found dose rates to the urologist of up to 1100 mrem per hour of flouroscopy time. The maximum yearly whole-body exposure as recommended by the National Council on Radiation Protection is 5000 mrem, or 5 rem. CONCLUSIONS: Urologists should be cognizant of this radiation risk, and the concepts of time, distance, and shielding are critically important to know in efforts to reduce radiation exposure. We introduce a newly designed fluoroscopic drape which reduces the radiation dosage to the urologist from scatter nearly 70-fold. We found this shield to be very practical and easy to use, and we offer it as an effective safeguard against secondary radiation exposure.

Data Collection↗
PubMed1996

Clinical audit of ciprofloxacin use in adults admitted to hospital with gastroenteritis.

We audited the use of ciprofloxacin, before and after the introduction of simple clinical guidelines, in adults admitted to a regional infectious diseases unit with presumed gastroenteritis. The case notes of 128 consecutive adult admissions over 6 months in 1993 were reviewed and a comparable group of 125 adults in 1994 were prospectively followed. The discharge diagnosis was infective gastroenteritis in 73% of the 1993 admissions and 75% of the 1994 admissions, of whom 42% and 51% had confirmed bacterial enteropathogens. The 1994 cohort appeared to be more ill, with longer duration of symptoms prior to admission, more patients with profuse diarrhoea prior to admission, and longer mean duration of hospital stay. The proportion of patients with a discharge diagnosis of gastroenteritis who received ciprofloxacin did not change (64% in 1993, 67% in 1994) but the proportion of these patients who were subsequently found to be culture-positive rose from 54% to 68%. The proportion of patients receiving intravenous ciprofloxacin fell from 20% to 10% and the total number of doses (intravenous and oral) fell from 1027 in 1993 to 768 in 1994, with cost savings of pound 1465 over 6 months. The benefits and drawbacks of empirical use of ciprofloxacin are discussed. Our audit suggests that simple clinical guidelines can assist in identifying suitable patients for empirical antimicrobial therapy, and result in substantial cost savings.

Adult↗
PubMed1996

Right atrium thrombosis in patients on hemodialysis.

Vascular access has been the Achilles heel of hemodialysis for many years, and placement of temporary subclavian and internal jugular vein catheters has been a daily practice for the nephrologist. Now, concern about central vein stenosis, well described with the use of subclavian catheters in end-stage renal disease (ESRD), has prompted the use of internal jugular vein permanent catheters to avoid this complication, so as not to hinder future arteriovenous grafts. Permanent catheter access is not without its own special problems, and we describe here two patients that developed thrombosis of the right atrium while receiving hemodialysis through a permanent internal jugular catheter.

Adult↗
PubMed1996

Intrathecal morphine: one year's experience in cardiac surgical patients.

OBJECTIVES: This study was designed to assess the benefits and complications associated with the use of intrathecal morphine (ITM) in patients undergoing coronary artery bypass surgery (CABG). DESIGN: This was a retrospective chart review. SETTING: The study was performed in a single hospital that is affiliated with a university medical school. PARTICIPANTS: The charts of all patients who presented for CABG in a 12-month period were reviewed. INTERVENTIONS: All patients entered into the study had received ITM (0.03 mg/kg) at induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Complete data were available for 152 patients (86%). Median duration of ventilation postoperatively was 12 hours, and median duration of stay in the ICU was 72 hours. All patients received additional postoperative opioid analgesia, many by the epidural route. Fifteen percent developed respiratory complications, and the incidence of respiratory depression was 1.9%. Thirty-five percent required inotropic support; 17% percent were treated for hypertension; and 49% received antiarrhythmic therapy. The re-infarction rate was 2.6%, and 3% developed cardiac tamponade. Three patients developed neurologic complications unrelated to lumbar puncture. There were no in-hospital deaths. CONCLUSIONS: ITM is safe and provides effective pain relief after cardiac surgery. The high incidence of respiratory depression confirms the need for close observation of these patients postoperatively.

Aged↗