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Biomedical subjects

R W Taylor

Publications and source records attributed to R W Taylor.

At least 19 recordsLinked to original sources
PubMed1992

Measurement of acyl-CoA dehydrogenase activity in cultured skin fibroblasts and blood platelets.

The measurement of acyl-CoA dehydrogenase activity is an essential part of the investigation of patients with suspected defects of fatty acid oxidation, and recently the organometallic oxidant ferricenium hexafluorophosphate has been introduced as an electron acceptor for these assays. However, we show that when medium-chain acyl-CoA dehydrogenase activity was measured in cultured skin fibroblasts and platelets from patients with proven defects of this enzyme, there was considerable residual enzyme activity when this electron acceptor was used. The ferricenium assay is not as specific as the anaerobic ETF-linked assay in the biochemical diagnosis of medium-chain acyl-CoA dehydrogenase deficiency in fibroblasts, and therefore is of limited clinical applicability in its present form.

Acyl-CoA Dehydrogenases↗
PubMed1992

The mouse alpha 1(XII) and human alpha 1(XII)-like collagen genes are localized on mouse chromosome 9 and human chromosome 6.

Type XII collagen is a member of the FACIT (fibril-associated collagens with interrupted triple helices) group of extracellular matrix proteins. Like the other members of this group, collagen types IX and XIV, type XII has alternating triple-helical and non-triple-helical domains. Because of its structure, its association with collagen fibrils, and its distribution in dense connective tissues, type XII is thought possibly to act as a cross-bridge between fibrils and resist shear forces caused by tension. A portion of the ffuse gene was isolated by screening a genomic library with a chicken alpha 1 (XII) cDNA probe, followed by subcloning and sequence analysis. Comparison of exon sequences with the sequence of a mouse cDNA clone allowed the mouse gene to be identified as the alpha 1 (XII) collagen gene. In the mouse, Col12a1 is located on chromosome 9, as determined by linkage analysis using DNA from interspecific backcrosses with Mus spretus. Screening of a human genomic library also allowed the isolation of a human alpha 1(XII)-like gene (CoL12A1). This gene was mapped to chromosome 6 by blot hybridization to DNA from human/hamster hybrid cell lines. This information should prove useful in determining the role of type XII collagen genes as candidate genes in inheritable connective tissue diseases.

Amino Acid Sequence↗
PubMed1992

Chloride ion in intensive care medicine.

OBJECTIVE: To review the physiology of the chloride ion and its relationship to various disease states encountered in the ICU. Special emphasis was paid to the renal handling of chloride and its role in the evaluation of the urine and serum anion gaps. Metabolic acidosis and alkalosis are discussed. DATA SOURCES: English-language articles were identified through a search of the MEDLINE and Index Medicus databases. Bibliographies of retrieved articles were examined for relevant articles. STUDY SELECTION: Approximately 125 articles and 25 textbook chapters were reviewed. Those articles most applicable to the ICU were used. Information contained in text chapters was included primarily in the tables. DATA EXTRACTION: All available information was reviewed and analyzed by the authors before inclusion. DATA SYNTHESIS: Guidelines for the evaluation of urine and serum electrolyte concentrations are presented. The use of the urine anion gap is discussed, particularly as it relates to the diagnosis of hyperchloremic metabolic acidosis. Stool chloride provides information relevant to congenital and acquired diarrheas. The evaluation of metabolic acidosis requires the calculation of the serum anion gap. Both normal and increased gap acidoses are discussed, although increased gap acidoses are more commonly encountered in the ICU. Urine chloride is invaluable in defining whether the metabolic alkalosis is sodium-chloride responsive (urine chloride less than 10 mmol/L) or sodium chloride-unresponsive (urine chloride greater than 20 mmol/L). CONCLUSIONS: Measurement of chloride is a valuable tool in the evaluation and treatment of a variety of disorders. Serum chloride is most helpful in assessing both normal and increased anion gap metabolic acidoses, while urine chloride finds utility in the diagnosis of metabolic alkalosis and hyperchloremia metabolic acidosis. The evaluation of any disturbance in chloride homeostasis that defies easy explanation necessitates the measurement of stool electrolytes.

Acid-Base Equilibrium↗
PubMed1992

Pericardiocentesis.

Cardiac tamponade is a life-threatening condition resulting from compression of the cardiac chambers by a pericardial effusion. The principal cause of pericardial effusion is malignant disease of the pericardium, but infectious causes and cardiac trauma are common as well. The patient with cardiac tamponade demonstrates an abnormal pulsus paradoxus, and clinical signs of shock and impending cardiovascular collapse occur with very severe cardiac compression. Relief of the increased intrapericardial pressure is mandatory to establish adequate cardiac output. The definitive treatment of cardiac tamponade is emergent removal of enough pericardial fluid to acutely lower intrapericardial pressure. Echocardiographic guidance may be used if immediately available, but is not required to perform pericardiocentesis in a critical situation. Placement of a pulmonary artery catheter prior to pericardiocentesis is not indicated in cardiac tamponade. Once cardiac output and tissue perfusion have been restored, further drainage procedures such as pericardial catheter placement or surgical drainage are indicated. Therapeutic measures to address the underlying disease process should be initiated after pericardial drainage is accomplished.

Aftercare↗
PubMed1992

Robotic method for the analysis of morphine and codeine in urine.

A totally automated procedure has been developed for the detection and quantitation of morphine and codeine in urine case samples. The samples were initially screened for these drugs by a Syva EMIT Toxicology System (ETS). A Zymate laboratory robotic system confirms positive samples from Syva ETS by performing the hydrolysis, extraction, and derivatization of morphine and codeine. The derivatized morphine and codeine were detected using gas chromatography/mass spectrometry (GC/MS). Enzymatic hydrolysis conditions were experimentally optimized during method development. The automation of these procedures has proven to be reliable and efficient.

Codeine↗
PubMed1992

Occupational exposure to cocaine involving crime lab personnel.

The possibility of exposure to cocaine as a result of analyzing it or handling material contaminated by it has been a major concern of laboratory personnel. Several different work environments and simulated situations were examined to assess the likelihood of this type of exposure occurring. Urine specimens were collected and evaluated for cocaine and benzoylecgonine using the Syva ETS System (EMIT). Each specimen was analyzed for the two substances using gas chromatography/mass spectrometry (GC/MS). Urine specimens of laboratory-management personnel not working with drug samples showed no trace of cocaine or benzoylecgonine. A urinary benzoylecgonine level of 227 ng/mL was found in the specimen from one narcotics criminalist who was working on a routine case of 2 kilos of cocaine hydrochloride in the Narcotics Laboratory. A maximal urinary benzoylecgonine concentration of 1570 ng/mL was determined in the urine specimen from one narcotics criminalist who was sampling a case containing 50 kilos of cocaine hydrochloride over a period of 3 h. Decreasing the levels of airborne cocaine dust appears to minimize the amount of cocaine absorbed by the criminalists. Gloves, face masks, and goggles prove to be effective in minimizing exposure.

Air Pollution, Indoor↗
PubMed1991

The formation constants of ionomycin with divalent cations in 80% methanol/water.

The protonation constants and complex formation constants of ionomycin have been determined in 80% methanol/water (w/w) at 25.0 degrees C and mu = 0.050 (tetraethylammonium perchlorate). Potentiometric and spectrometric titration techniques give the following values for the mixed-mode protonation constants of ionomycin: log KH1 = 11.94 +/- 0.02 and log KH2 = 6.80 +/- 0.03. Comparison of these values with those for model compounds indicates that KH1 and KH2 refer to equilibria involving the beta-diketone and carboxylic acid moieties, respectively. Titrations of ionomycin with metal ion at fixed values of pH produced changes in the UV-visual absorbance spectra which were analyzed to give conditional complex formation constants, KMI'. The pH dependence of the values of KMI' indicated that 1:1 divalent metal ion-ionomycin (MI) complexes and protonated MHI+ complexes were formed in the pH range studied. The values of log KMI ranged from 5.30 +/- 0.11 for Sr2+ to 10.25 +/- 0.03 for Ni2+. The selectivity pattern and relative affinities (in parentheses) for the formation of the species MI are as follows: Ni2+ (2000) greater than Zn2+ (600) greater than CO2+ (440) greater than Mn2+ (47) greater than Mg2+ (1.00) greater than Ca2+ (0.21) greater than Sr2+ (0.022). Logarithmic values of KMHI, for the reaction MI + H+ in equilibrium MHI+, ranged from 5.9 (Ni2+) to 8.4 (Sr2+). Calculations using the values of the equilibrium constants determined indicate that an appreciable fraction of the complexed ionophore exists as the protonated complex, MHI+, in the pH range of 6.5-8.5.

Cations↗
PubMed1991

Effects of solute concentration on the entrapment of solutes in phospholipid vesicles prepared by freeze-thaw extrusion.

Phospholipid vesicles prepared by the freeze-thaw extrusion method contain internal solute concentrations which are much higher than the external values (entrapment ratios much greater than 1). This concentrating effect is a complex function of the total impermeant solute concentration in the medium used to prepare vesicles, the presence or absence of permeant solutes in the medium and the apparent competitive binding interactions between solutes and phospholipid. Increases in water phase solute concentration during freezing are thought to underlie the concentrating phenomenon, while osmotic pressure driven lysis of vesicles during thawing appears to limit its magnitude. By judicious selection of solute concentration and physical properties, further increases in the entrapment ratio should be obtainable, improving the usefulness of these vesicles as drug delivery vesicles and experimental systems.

Calcium↗
PubMed1991

The use of role-play in teaching medical students obstetrics and gynaecology.

There is a great need to review and critically assess medical education. Role-play has seen increasing use as an educational tool. We investigated its role in a 'conventional speciality', Obstetrics and Gynaecology. This is a part of the medical curriculum where communication skills are particularly important, but difficult to learn in practice. Twenty-one medical students took part in three role-play case studies. An innovation we implemented was the use of 'time outs' which could be called at any time through a session. After the exercise students were required to complete a questionnaire designed to probe their attitudes towards the experience. The results indicate that this technique can be successfully used in teaching a conventional speciality. Unlike some previous studies we also found this to be a satisfactory tool in teaching the factual part of the course. We found the 'time out' innovation to be an important aid. We argue that there is an important niche for role-play in medical education.

Clinical Competence↗
PubMed1979

Female sex hormone receptors and their importance in clinical practice.

We now know a great deal about the early steps in the induction of a steroid hormone response at the cellular level. This helps to explain some of the observed clinical responses and also the development of some congenital anomalies. The importance of progesterone as a balance to the proliferative effects of extrogen both in hormone replacement therapy and in the hormone-sensitive tumors is clear. It is hoped that further studies will guide us to ways in which we might enhance these benefits.

Adult↗
PubMed1979

Albuterol and isoproterenol in bronchial asthma. Efficacy and toxicity of drugs administered via intermittent positive pressure breathing.

This study compared the efficacy and side effects of 1.25, 2.5, 5, 10, and 15 mg of albuterol and isoproterenol hydrochloride administered by intermittent positive pressure breathing (IPPB) to 12 patients with reversible airway obstruction. Equal doses of the two medications induced similar peak increases in pulmonary function, but the increase following albuterol persisted longer. The degree of bronchodilation was impressive; 15 mg of albuterol induced a mean increase over six hours of 82% in the forced expiratory volume in one second. Significant cardiovascular side effects were more common after isoproterenol than after albuterol. Albuterol is superior to isoproterenol as a bronchodilator when administered by IPPB because, for a given peak bronchodilation, cardiovascular side effects are fewer and bronchodilation persists longer with albuterol. The optimal dose of isoproterenol hydrochloride is 2.5 to 5.0 mg and the optimal dose of albuterol is 10 mg when these drugs are given by IPPB.

Adult↗
PubMed1978

Normal human endometrium in cell culture. I. Separation and characterization of epithelial and stromal components in vitro.

Separation of human endometrium into its epithelial and stromal components has been achieved through collagenase digestion and has permitted a study of these two cell populations under specific experimental culture conditions. The stromal cell populations showed a progesterone response, were easily handled in culture, and displayed a limited in vitro life span typical of human diploid fibroblasts. In contrast, epithelium only survived in short-term primary culture and showed no clear hormone response. High-density epithelial cultures remained viable for longer periods in culture. Comparisons between resurfacing endometrial epithelial cells in vivo and epithelial cells migrating from explants in vitro suggested that this initial epithelial migration in vitro was the counterpart of the repair response in vivo.

Cell Movement↗
PubMed1978

Integration of general-practitioner and specialist antenatal care.

Despite the growing role of specialist obstetricians in intranatal care the importance of the general practitioner's role, especially in antenatal and postnatal care, is being increasingly recognized. We describe a new way of sharing care which involves the consultant obstetrician attending antenatal sessions at fortnightly intervals in the practice. In addition the antenatal record is retained by the patient herself who brings it to all attendances, both in the practice and at the hospital.We analysed the results of this arrangement and compared them with a controlled series of hospital patients and found some advantages for shared care arrangements including, in particular, a reduction in the number of different doctors seen by patients, a big reduction in the number of patients who were seen by more than three doctors, and an increase in the breast feeding rate at the time of discharge from hospital.

Family Practice↗