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Biomedical subjects

M Warner

Publications and source records attributed to M Warner.

At least 181 records · Page 10Linked to original sources
PubMed1991

Automated nurse scheduling.

This article attempts (1) to define the several aspects of scheduling nursing personnel within the general context of nursing management, (2) to briefly review the history of the application of operations research and computers to scheduling nurses, (3) to describe what nursing administration is looking for in an automated scheduling system, (4) to review a typical system, and then (5) to discuss issues of implementation from the viewpoint of nursing administration, including realizable benefits.

Computers↗
PubMed1990

New brush-needle for percutaneous biopsy.

A new 21-gauge coaxial brush biopsy needle system is described. Preliminary tests were performed on 20 surgically resected specimens, and the results were compared with those obtained in biopsies taken with a 22-gauge Chiba needle. The brush needle specimens demonstrated a greater yield of biopsy material and better cellularity than those obtained with the Chiba needle, permitting diagnosis in a larger number of specimens. The results of this preliminary study indicate that the use of a brush-type coaxial device can enhance the yield of materials obtained through a small-gauge biopsy needle.

Biopsy, Needle↗
PubMed1989

Electrophoretic typing of Enterobacter cloacae with a limited set of enzyme stains.

Hospital isolates of Enterobacter cloacae were analysed by polyacrylamide gel electrophoresis for enzyme polymorphism and the results were compared with established serotyping, phage typing and biotyping techniques. Initially, the diversity of electromorphs of 13 enzymes was determined on a representative set of 62 distinct strains. Two broad clusters of strains were found in the species, and analysis by serotype suggested a limited diversity within the most frequent O serotypes. A subset of three enzymes, lactate dehydrogenase, 6-phosphogluconate dehydrogenase, glutamate dehydrogenase and an unidentified marker, were selected and used to type groups of hospital isolates. There was good general agreement between the two systems, although the enzyme method failed to distinguish between some strains with the same serotype. This method provided useful epidemiological information and, in the absence of established typing systems, it is a practical approach to subdividing the species.

Bacterial Typing Techniques↗
PubMed1989

Distribution and regulation of 5 alpha-androstane-3 beta,17 beta-diol hydroxylase in the rat central nervous system.

5 alpha-Androstane-3 beta,17 beta-diol hydroxylase (3 beta-diol OHase), a form of cytochrome P-450 whose main function is thought to be the elimination of dihydrotestosterone (DHT) from its target tissues, was found in the central nervous system (CNS) of both male and female rats at a level which is at least 300-fold higher than any other P-450 catalyzed steroid hydroxylase in the brain. In order to gain some insight into the physiological function of this enzyme we have studied its distribution throughout the CNS as well as the effects of age and hormonal manipulations of rats. We have also partially purified the enzyme from the brain and compared it with the 3 beta-diol OHase in the prostate. 3 beta-Diol OHase activity was distributed throughout the CNS of adult male and female rats with levels between 70-153 nmol products formed/g tissue.h. The products were identified as 5 alpha-androstane-3 beta,7 beta,17 beta-triol,5 alpha-androstane-3 beta,6 alpha,17 beta-triol and 5 alpha-androstane-3 beta,7 alpha,17 beta-triol. The ratio of these three triols was 1:9:3. Catalytic activity was not affected by castration or adrenalectomy of male rats, or during late pregnancy or lactation in females. In the brains of 14-day-old fetuses and 2-day-old rats, the level of 3 beta-diol OHase was 30% of that of adults and it increased to adult levels by day 28. Cytochrome P-450 was partially purified from microsomes of whole brain, hypothalamus, and prostate and 3 beta-diol OHase activity reconstituted. On the basis of the ratios of the three triols formed from 3 beta-diol, it can be concluded that the 3 beta-diol OHase in the brain is similar to that in the prostate. From a comparison of the turnover numbers in reconstituted systems with P-450 prepared from the prostate, brain, and hypothalamus, it can be estimated that up to 50% of the P-450 in the hypothalamus and 10% in whole brain is 3 beta-diol OHase. Supportive evidence for this relative distribution of 3 beta-diol OHase in the hypothalamus was obtained by comparing the sodium dodecyl sulfate electrophoretic profiles of P-450 obtained from the hypothalamus and prostate microsomes.

Adrenalectomy↗
PubMed1989

Endocrine regulation of cytochrome P-450 in the rat brain and pituitary gland.

In an effort to understand the physiological functions of cytochrome P-450 in the central nervous system and pituitary gland, we evaluated changes in the level of the enzyme as a function of the endocrine status of rats and the ability of these tissues to synthesize or degrade steroids. The P-450 content of microsomes prepared from the hypothalamic preoptic area (HPOA), the olfactory lobes and the cerebrum was 0.040 +/- 0.009 and in the pituitary gland 2.2 +/- 0.6 (S.D.) nmol/g tissue. The P-450 content of the HPOA and olfactory lobes, but not of the rest of the cerebrum, was influenced by the endocrine status of rats. In microsomes it increased five- to tenfold over control levels during late pregnancy in the olfactory lobes and during lactation in the HPOA, and in both brain regions treatment of rats with 5 alpha-dihydrotestosterone (DHT) caused an eight- to tenfold increase in the P-450 content. Androstenedione was not a good substrate for brain P-450. The level of androstenedione 19-hydroxylase in the olfactory lobe microsomal fraction was 0.50 +/- 0.06 nmol 19-hydroxyandrostenedione formed/g tissue per h. This activity was tenfold lower in other brain areas and was not detectable in the pituitary gland. The rate of aromatization of androstenedione to oestradiol in the HPOA and olfactory lobe of lactating rats was 0.46 +/- 0.14 and 0.38 +/- 0.05 pmol/oestradiol formed/g tissue per h respectively. 5 alpha-Androstane-3 beta,17 beta-diol (A-5 alpha-3 beta,17 beta-diol) was a much better substrate for P-450 throughout the brain and pituitary gland.(ABSTRACT TRUNCATED AT 250 WORDS)

5-alpha-Dihydroprogesterone↗
PubMed1988

Immunohistochemical localization of cytochrome P-450 in the rat brain.

Immunohistochemical localization of cytochrome P-450 in the brains of normal untreated male rats has been demonstrated with polyclonal antibodies raised against hepatic P-450C. These antibodies recognize P-450C and D, two closely related forms of P-450. We have identified P-450C,D immunoreactivity (P-450C,D-i) within both neurons and glial cells. Neuronal cell bodies showing P-450C,D-i were present in several forebrain areas, including the olfactory bulb, the caudate nucleus, the cingulate, the frontal and the entorhinal cortex, the hippocampus and the thalamus. In the brainstem, P-450C,D-i neurons were detected in the substantia nigra, the nucleus locus coeruleus, raphe nucleus, reticular formation and the trigeminal nerve nucleus and the dorsal motor nucleus of the vagus. Glial cells containing P-450C,D-i were situated within myelinated fiber tracts in the forebrain (e.g. the corpus callosum, the internal capsule) and the brainstem (e.g. the superior cerebellar peduncle, the medial longitudinal fasciculus). Some, but not all, of the P-450C,D-i glial cells also stained with an antibody against glial fibrillary acidic protein. The present findings represent the first immunohistochemical demonstration of cytochrome P-450 in the brain and suggest that cytochrome P-450C,D is constitutive in neurons and glial cells of most brain regions throughout the rat neuraxis.

Animals↗
PubMed1988

Prospective addition of beta-lactamase to blood culture medium.

The value of adding beta-lactamase to bottles of blood-culture medium before their distribution to wards was investigated. Significantly more bottles containing beta-lactamase were culture-positive than those without (p less than 0.002). In another series, when the enzyme was added to both bottles in each set there was no significant difference in isolation rates between the two bottles. The groups of organisms which were isolated more readily when beta-lactamase was present were staphylococci and streptococci. Storage of beta-lactamase (Genzyme broad-spectrum mixture) in blood-culture medium at room temperature resulted in rapid loss of cephalosporinase activity, whereas little decline in penicillinase activity was noted over a period of 118 days.

Anti-Bacterial Agents↗
PubMed1988

Regional distribution of cytochrome P-450 in the rat brain: spectral quantitation and contribution of P-450b,e, and P-450c,d.

The cytochrome P-450 (P-450) content of different regions of the rat brain was measured after partial purification of the enzyme from homogenates, and the quantitative contribution of P-450b,e and P-450c,d to brain P-450 was assessed by Western immunoblotting and immunohistochemistry using rabbit antibodies raised against purified hepatic P-450b and P-450c, respectively). P-450 could be quantitated by its reduced CO difference spectrum after chromatography of homogenates on p-chloroamphetamine-coupled Sepharose. The yield of P-450 from whole brain was 90 +/- 19 pmol/g of tissue, which is approximately 1% of the level in liver microsomes from control rats. The amount of P-450 recovered from homogenates of olfactory lobes, hypothalamus, thalamus, striatum, cerebral cortex, and brainstem varied between 40 and 100 pmol/g of tissue. The cerebellum was a region of exceptionally high P-450 content, with yields of up to 400 pmol/g whereas the substantia nigra yielded only 16-20 pmol/g. Immunohistochemical studies with anti-P-450b and anti-P-450c revealed intense staining of a limited number of cells in the cerebellum with both antibodies and in the thalamus only with anti-P-450c. In the cerebellum, both anti-P-450b and anti-P-450c stained the Bergmann glial cells together with their radial processes. Individual glial cells in the granular cell layer were also stained. There was no staining of Purkinje cells. In the thalamus, anti-P-450b gave weak staining of certain astroglia, but with anti-P-450c, there was intense staining of neuronal somata.(ABSTRACT TRUNCATED AT 250 WORDS)

7-Alkoxycoumarin O-Dealkylase↗
PubMed1988

Automated screening of blood cultures with the Malthus microbiological growth analyser.

A total of 3347 blood cultures from patients in all hospital wards were examined on a Malthus microbiological growth analyser and by a conventional system. There was no significant difference in the total numbers of positive cultures of clinical importance between the two systems (p greater than 0.05). Staphylococcus aureus, however, was isolated more often by the conventional method (p less than 0.05). Failure of the automatic detection routine limited the potential of the Malthus system for earlier detection of positive cultures. Daily visual examination of Malthus curves and subculture of bottles not promptly attached to the apparatus were necessary to avoid missing some positive cultures. False positive rates were 13% for the Malthus system and 2% for the conventional system. The contamination rate was considerably lower in the Malthus system (p less than 0.001). Further development would be necessary for the apparatus to be acceptable for routine screening of blood cultures.

Bacteria↗
PubMed1988

Supervising lithium. A comparison of a lithium clinic, psychiatric out-patient clinics, and general practice.

Supervision of lithium treatment among three groups of patients treated in different settings - at a lithium clinic, as hospital out-patients, and by a GP - was studied. The lithium clinic maintained lower levels and checked these more frequently. Elevated lithium levels were most frequent in the GP-supervised group, which also included the 13 patients with the most impaired glomerular filtration. In hospital settings GFR-impaired patients received a lower daily dose of lithium; in general practice, affected patients had a higher mean serum lithium level and were more frequently prescribed lithium once daily. We conclude that patients with glomerular impairment who require lithium should be supervised by a specialist, or at least prescribed lithium in divided daily doses.

Ambulatory Care↗
PubMed1988

Parathyroid hormone desensitization in renal membranes of vitamin D-deficient rats is associated with a postreceptor defect.

We examined the characteristics of PTH resistance in vitamin D-deficient rats employing renal membranes in vitro. Homologous desensitization was characterized by diminished PTH-stimulated adenylate cyclase activity and was associated with a reduction in PTH-binding capacity, but not affinity. Heterologous desensitization was also seen, as manifested by decreased calcitonin (CT)-stimulated adenylate cyclase activity with normal CT receptor binding. The reduced capacity of the nonhormonal effectors NaF and guanylylimidodiphosphate to stimulate adenylate cyclase indicated a postreceptor defect at the level of the guanyl nucleotide-binding protein (G protein), whereas a normal forskolin response was consistent with a fully functional catalytic component. The G protein deficiency was confirmed by demonstrating that the addition of extracts of vitamin D-sufficient membranes to preparations of vitamin D-deficient membranes restored the normal responses to NaF and guanylylimidodiphosphate. In addition, cholera toxin- and pertussis toxin-catalyzed labeling of vitamin D-deficient renal membranes with [32P]NAD revealed a decrease in both the stimulatory and inhibitory binding proteins. Experiments with testicular membranes in vitro indicated that the adenylate cyclase abnormality was absent in tissue lacking PTH receptors. The results suggest that a major contribution to PTH resistance in vitamin D-deficient animals is a postreceptor defect at the level of the G proteins and that this defect is manifest only in tissue expressing the PTH receptor.

Adenosine Diphosphate Ribose↗
PubMed1988

Cytochrome P-450 b and c in the rat brain and pituitary gland.

A quantitative assessment of the levels of cytochromes P-450 b and P-450 c in the brains and pituitary glands of untreated and beta-naphthoflavone (BNF)-pretreated rats was made with polyclonal antibodies raised against hepatic P-450 b and c and the sensitive fluorometric assay of P-450 catalytic activity, namely, the O-deethylation of ethoxycoumarin (ETC). In the microsomal fraction of brains of untreated rats, the rate of formation of 7-hydroxycoumarin from ETC ranged between 0.1 and 20 pmol/min/mg of microsomal protein, which is approximately 0.01-2% of the level of hepatic microsomes of phenobarbital-induced rats. This brain activity was completely inhibited by anti P-450 b antibodies but was unaffected by anti P-450 c antibodies. As with hepatic P-450 b, metyrapone and chloramphenicol (100 microM) were good inhibitors of catalytic activity, whereas alpha-naphthoflavone (1 microM) was a poor inhibitor. No ETC O-deethylase activity was detectable in microsomes prepared from the pituitary glands of untreated rats. Upon pretreatment of rats with BNF, there was induction of ETC O-deethylase activity in the pituitary gland to a level of 3.3 +/- 1.5 pmol/min/mg of microsomal protein, but there was no significant increase in the level of activity in brain microsomes. Despite this, there was evidence of induction of P-450 c in both the brain and pituitary of BNF-pretreated rats since anti P-450 c antibodies inhibited brain activity by 55% and pituitary activity by 84%. The regional distribution of P-450 b and c in the hypothalamic-preoptic area and olfactory bulbs was examined. The level of ETC O-deethylase activity in the hypothalamic-preoptic area was not different from that in the whole brain, but in the olfactory bulbs activity was higher than that in whole brain, with a range of 0.1-52 pmol/min/mg of microsomal protein. The catalytic activity in the whole brain and in the olfactory bulbs was inhibited by anti P-450b but not by anti P-450c antibodies. Neither estradiol, testosterone, dehydrotestosterone, nor 5 alpha-androstane,3 beta,17 beta-diol (100 microM) competitively inhibited ETC O-deethylase activity, indicating that P-450 b is not responsible for the steroid hydroxylations previously reported in the brain. BNS pretreatment of rats did not cause a consistent increase in ETC O-deethylase upon BNF induction. However, there was an induction of P-450 c in the olfactory bulbs since catalytic activity was inhibited with anti P-450c antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)

7-Alkoxycoumarin O-Dealkylase↗