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Biomedical subjects

C M Wilson

Publications and source records attributed to C M Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1991

A comparison of lignocaine with prilocaine in axillary brachial plexus anaesthesia.

Twenty patients received either lignocaine 1.5% with 1/200,000 adrenaline (group L), or prilocaine 1.5% plain (group P) as a brachial plexus block for surgery to the upper limb, in a randomised double-blind study. The two groups were comparable in age, weight and duration of surgery and there were no significant differences between the two groups with regard to onset, pattern or degree of sensory loss. The degree of motor loss was also comparable. The group L patients had a statistically significant longer duration of sensory loss than those in group P. All the blocks were performed using the same technique and provided complete surgical anaesthesia. Prilocaine 1.5% plain provides adequate sensory and motor blockade for brachial plexus anaesthesia and is a suitable agent for medium duration surgery to the upper limb.

Adult↗
PubMed1991

Hormonal effects on the surfactant protein B (SP-B) mRNA in cultured fetal rat lung.

Glucocorticoids, triiodothyronine (T3), and cyclic adenosine monophosphate (cAMP) have been shown previously to modulate phosphatidylcholine and surfactant protein A (SP-A) synthesis in fetal rat lung explant cultures. In this report, we have examined the hormonal regulation of the rat surfactant protein B (SP-B) mRNA to determine whether SP-B expression is coordinately regulated with the surfactant phospholipids or with SP-A. Dexamethasone (1 to 200 nM) and cAMP (200 microM) had a stimulatory effect on SP-B mRNA levels, whereas T3 tended to inhibit the accumulation of SP-B mRNA. In combination experiments, treatment with dibutyryl-cAMP (200 microM) and dexamethasone (100 nM) resulted in about a 22-fold increase, whereas dexamethasone or dibutyryl-cAMP alone produced 18- and 2-fold increases, respectively. When the cAMP analogue 8-bromo-cAMP (200 microM) was used in combination with dexamethasone, there was no significant difference between the combined effect and that of dexamethasone alone. T3 treatment, however, resulted in a significant reduction of the dexamethasone-induced stimulation from about a 22-fold to a 14-fold increase. Tissue in situ hybridization showed that dexamethasone stimulated the levels of SP-B mRNA in cells from both the alveolar and bronchiolar epithelium. These data indicate that there are differences in the hormonal regulation of the components of surfactant, suggesting that they are independently regulated.

Animals↗
PubMed1991

Thrombolytic therapy within one hour of the onset of acute myocardial infarction.

Between 1986 and 1988, 239 consecutive patients with acute myocardial infarction received thrombolytic therapy up to 285 minutes after onset of symptoms; in 39 (17 with anterior infarction, 21 inferior, one lateral infarction) recombinant tissue plasminogen activator or anistreplase was administered a mean of 51 minutes (range 20-60 minutes) after the onset of symptoms. The patency rates (26 of 30; 87 per cent), rapid ST segment resolution (36 of 38; 95 per cent) and QRS score of less than or equal to 3 (28 of 38; 74 per cent) were statistically significantly higher for those seen and treated in the first hour in comparison with those seen and treated later. For those treated within the first hour mean peak creatine kinase was 1264 U/l for those with TIMI grade 2 or 3 (partial or complete perfusion) compared with 3005 U/l for those with TIMI grade 0 or 1 (no perfusion or penetration without perfusion) (p = 0.02): mean peak creatine kinase-MB for those with TIMI grade 2 or 3 perfusion was 115 U/l compared with 312 U/l for those with TIMI grade 0 or 1 (p = 0.01). Four of the 39 patients developed ventricular fibrillation following thrombolytic therapy, three within 24 hours of infarction and one following reinfarction on day 15. There were no significant bleeding complications. One patient died. Thrombolytic therapy within 1 hour of the onset of symptoms led to a very high angiographic patency rate, rapid ST segment resolution with preservation of left ventricular function. This therapy is without significant complications.

Anistreplase↗
PubMed1990

Androgen receptor gene expression in human prostate carcinoma cell lines.

Responses to androgen vary widely among prostate cancers and prostatic carcinoma cell lines. We have explored the basis for this heterogeneity by examining the levels of androgen receptor expression in a prostate carcinoma cell line (LNCaP) that expresses the androgen receptor and two prostate carcinoma cell lines that do not contain detectable androgen receptor. We find that while the LNCaP cell line contains high levels of both the androgen receptor protein and mRNA, the receptor-negative cell lines DU-145 and PC-3 do not express androgen receptor protein as detected by immunoblotting or mRNA as detected by Northern analysis or S1 nuclease protection. These results indicate that the absence of androgen receptor expression in the androgen receptor-negative cell lines is caused by diminished androgen receptor mRNA levels. Genomic Southern analysis indicates that the differences in androgen receptor expression in each of these cell lines is not associated with detectable alterations in the structure of the androgen receptor gene.

Cell Line↗
PubMed1990

Transient release of lipid peroxides after coronary artery balloon angioplasty.

Free radical production may cause myocardial damage during reperfusion of ischaemic myocardial tissue; when free radicals interact with polyunsaturated fatty acids or their esters, lipid peroxides are produced. A product of lipid peroxidation, malondialdehyde, was measured in 10 subjects with stable angina who underwent angioplasty of a proximal high-grade stenosis (over 90%) of the left anterior descending coronary artery. In all subjects the duration of balloon occlusion was 60 s. Blood was withdrawn from the great cardiac vein immediately before balloon inflation (T0), immediately after balloon deflation (T60), 15 s after balloon deflation (T75), and 1 min after balloon deflation (T120). There was a significant increase in malondialdehyde at T60 compared with T0 for the first balloon inflation (mean increase 0.3 mumol/l [95% confidence limits 0.1, 0.5]), and at both T60 (0.31 mumol/l [0.15, 0.47]) and T75 (0.22 mumol/l [0.04, 0.40]) for the second balloon inflation. This model could be used to assess antioxidant effects of drugs.

Adult↗
PubMed1990

Scedosporium inflatum: clinical spectrum of a newly recognized pathogen.

The clinical course of 11 patients is reported: a newly-described species, Scedosporium inflatum, was isolated from each. Infections were primarily focally invasive and involved musculoskeletal tissues. All but one followed penetrating trauma, often minor, or surgery. Two cases, one fatal, occurred in immunosuppressed patients. In only one case was there presumptive hematogenous spread. In three cases colonization with S. inflatum could not reliably be distinguished from infection. In vitro susceptibility testing of isolates from all patients showed that all were resistant to amphotericin B, miconazole, and ketoconazole and most were resistant to fluconazole and itraconazole. The optimum management of S. inflatum infection is not apparent: Although several patients recovered without antifungal therapy, progressive unremitting infection occurred in an immunocompromised patient and in a previously healthy child despite aggressive antifungal chemotherapy and surgical debridement.

Adult↗
PubMed1990

Response of enzymes and storage proteins of maize endosperm to nitrogen supply.

To examine the effects of N nutrition upon endosperm development, maize (Zea mays) kernels were grown in vitro with either 0, 3.6, 7.1, 14.3, or 35.7 millimolar N. Kernels were harvested at 20 days after pollination for determination of enzyme activities and again at maturity for quantification of storage products and electrophoretic separation of zeins. Endosperm dry weight, starch, zein-N, and nonzein-N all increased in mature kernels as N supply increased from zero to 14.3 millimolar. The activities of sucrose synthase, aldolase, phosphoglucomutase, glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, and acetolactate synthase increased from 1- to 2.5-fold with increasing N supply. Adenosine diphosphate-glucose pyrophosphorylase and both ATP- and PPi-dependent phosphofructokinases increased to lesser extents, while no significant response was detected for hexose kinases and glutamine synthetase. Nitrogen-induced changes in enzyme activities were often highly correlated with changes in final starch and/or zein-N contents. Separation of zeins indicated that these peptides were proportionately enhanced by N supply, with the exception of C-zein, which was relatively insensitive to N. These data indicate that at least a portion of the yield increase in maize produced by N fertilization is induced by a modification of kernel metabolism in response to N supply.

Journal Article↗
PubMed1990

Regulation of surfactant protein A mRNA by hormones and butyrate in cultured fetal rat lung.

We have previously shown that dexamethasone, triiodothyronine (T3) and dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP) stimulate phosphatidylcholine (PC) synthesis in fetal rat lung explants in culture. There are also additive interactions between these agents with regard to PC synthesis. In this study we examined the regulation of surfactant protein A (SP-A) mRNA in fetal rat lung in culture. Dexamethasone increased SP-A mRNA in the explants in a dose-dependent fashion (1-200 nM), but T3 did not. Whereas 8-bromo-cAMP increased SP-A mRNA, a decrease was observed with dibutyryl cAMP. These findings support the view that at least some of the genes involved in the synthesis of the various components of surfactant are independently regulated. Since we observed differences in the effects of a cAMP analogue which contained butyrate and one that did not, explants were then cultured with Na butyrate, a known regulator of gene expression. A significant decrease in SP-A mRNA was observed at mM concentrations. Exposure of the explants to alpha-aminobutyric acid, a butyric acid analogue which is elevated in the blood of infants of diabetic mothers, resulted in a significant decrease in SP-A mRNA at a concentration 1/25 of that required for Na butyrate. This observation raises the question of whether the decreased SP-A levels reported in fetuses of diabetic mothers may, at least in part, be related to this metabolite.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1990

A single nucleotide substitution introduces a premature termination codon into the androgen receptor gene of a patient with receptor-negative androgen resistance.

Mutations of the androgen receptor that impair the action of 5 alpha-dihydrotestosterone and testosterone result in abnormal male sexual development. The definition of the organization of the androgen receptor gene has permitted us to examine its structure in nine patients with androgen resistance that exhibit absent 5 alpha-dihydrotestosterone binding in cultured fibroblasts (receptor-negative androgen resistance). Using labeled probes specific for each individual coding exon, we find no gross rearrangements, insertions, or deletions of the androgen receptor gene in these patients. To analyze the genetic defect in these receptor-negative patients, we used the polymerase chain reaction to amplify each individual exon of the androgen receptor gene in nine affected patients. In all patients, the size of each amplified exon segment was identical to that in normal individuals. The nucleotide sequence of the entire coding region of the androgen receptor was determined in one of these patients. A single nucleotide substitution was identified that results in a premature termination codon in exon 6 at amino acid 794. S1 nuclease protection assays demonstrated that normal levels of androgen receptor mRNA are present in skin fibroblasts of this patient. Transfection of a mutated androgen receptor cDNA containing a termination codon at position 794 into eukaryotic cells resulted in formation of a normal amount of receptor protein, as indicated by immunoblotting, but the expressed protein does not bind 5 alpha-dihydrotestosterone. These findings suggest that the presence of a premature termination codon at amino acid 794 of the androgen receptor is the cause of androgen resistance in this patient.

Adolescent↗
PubMed1990

Antipeptide antibodies to two distinct regions of the androgen receptor localize the receptor protein to the nuclei of target cells in the rat and human prostate.

We have developed polyclonal antibodies to two synthetic peptides corresponding to the amino-(N-)terminal or carboxyl-(C-)terminal segments of the human androgen receptor (hAR) protein, as deduced from the nucleic acid sequence of the androgen receptor cDNA. Immunoreactive antisera were identified by solid phase enzyme-linked immunosorbent assay and purified by peptide affinity chromatography. Specific immunoreactivity with the hAR was confirmed by immunoblotting, using both a fusion protein produced in E. coli that contains the C-terminal 880-amino acid sequence of hAR and the full-length receptor protein produced in COS cells after transfection with a plasmid containing the entire hAR-coding region. Immunohistological evaluation of rat and human prostatic tissue using anti-C-terminal or anti-N-terminal antibodies demonstrated similar patterns of specific staining of the nuclei of epithelial and stromal cells. Castration resulted in a decrease in the amount of nuclear AR detected in the rat prostate after a short time of exposure to anti-C-terminal antibodies (less than 4 h), but did not alter the level of specific staining obtained with anti-N-terminal antibodies. This decrease in nuclear staining using anti-C-terminal antibodies could be reversed by treating castrated animals with dihydrotestosterone. When longer times of exposure to the primary antibodies were used, high levels of nuclear staining were obtained with both types of antibodies in prostate specimens from castrate as well as as intact rats. This immunohistochemical staining pattern contrasts with receptor measurements in rat prostate homogenates that indicate the partition of AR binding into the low salt (cytosolic) fraction in the castrate animal and into the high salt (nuclear) fraction in the intact animal. Our results suggest that the AR is predominantly a nuclear protein even in the absence of ligand and that dihydrotestosterone serves to tighten its association with the nucleus. These data also suggest that the immunoreactivity of anti-C-terminal antibodies is influenced by the presence of dihydrotestosterone, presumably via an alteration in the physical state of the receptor protein.

Amino Acid Sequence↗
PubMed1990

Definition of the human androgen receptor gene structure permits the identification of mutations that cause androgen resistance: premature termination of the receptor protein at amino acid residue 588 causes complete androgen resistance.

We have isolated and characterized the gene encoding the human androgen receptor. The coding sequence is divided into eight coding exons and spans a minimum of 54 kilobases. The positions of the exon boundaries are highly conserved when compared to the location of the exon boundaries of the chicken progesterone and human estrogen receptor genes. Definition of the intron/exon boundaries has permitted the synthesis of specific oligonucleotides for use in the amplification of segments of the androgen receptor gene from samples of total genomic DNA. This technique allows the analysis of all segments of the androgen receptor gene except a small region of exon 1 that encodes the glycine homopolymeric segment. Using these methods we have analyzed samples of DNA prepared from a patient with complete androgen resistance and have detected a single nucleotide substitution at nucleotide 1924 in exon 3 of the androgen receptor gene that results in the conversion of a lysine codon into a premature termination codon at amino acid position 588. The introduction of a termination codon into the sequence of the normal androgen receptor cDNA at this position leads to a decrease in the amount of mRNA encoding the human androgen receptor and the synthesis of a truncated receptor protein that is unable to bind ligand and is unable to activate the long terminal repeat of the mouse mammary tumor virus in cotransfection assays.

Amino Acid Sequence↗
PubMed1990

Chromatographic characterization of vasoactive intestinal polypeptide in guinea pig and rhesus monkey eyes.

Acid extracts of guinea pig and rhesus monkey anterior uvea, choroid and retina contain immunoreactive VIP. By reversed phase high performance liquid chromatography, the immunoreactive material from these ocular tissues elutes at a position similar to synthetic porcine VIP. Only in the guinea pig anterior uvea is a second smaller peak detected. By size exclusion high performance liquid chromatography, the peptide in the monkey anterior uvea, choroid and retina elutes in the identical position as the synthetic porcine VIP standard with an apparent molecular weight of 3450 daltons. We conclude that a single form of VIP, chromatographically similar to the porcine standard, is the predominant form of the peptide in the eye of guinea pig and rhesus monkey.

Animals↗
PubMed1989

Bands, interbands and puffs in native Drosophila polytene chromosomes are recognized by a monoclonal antibody to an epitope in the carboxy-terminal tail of histone H1.

A monoclonal antibody was raised against Drosophila melanogaster histone H1. Immunoscreening of proteolytic cleavage fragments of H1 and of a set of all possible overlapping synthetic octapeptides corresponding to the amino acid sequence of H1, revealed that the antibody recognizes an epitope within the sequence 207VTAAKPKA214 near the centre of the carboxy-terminal tail. This antibody gives positive immunofluorescence over the entire length of native D. melanogaster polytene chromosomes isolated from salivary glands by microdissection at physiological pH and ionic strength. Bands, interbands and puffs are all seen to contain H1. The immunofluorescence over puffs, albeit lower than that over bands and interbands, indicates that chromatin decondensation can occur without complete loss of H1 in these structures. The reaction of the antibody with bands suggests that the segment of the C-terminal tail containing the epitope may be exposed in the condensed 30 nm chromatin filament.

Amino Acid Sequence↗
PubMed1989

Transthoracic defibrillation threshold of sine and trapezoidal waveforms in defibrillation.

The transthoracic defibrillation threshold of trapezoidal (2.5-, 5-, 10-, 15-, 20-, 40-, and 55-msec duration) and damped sine waveforms were established in groups of anesthetized greyhounds. Of the seven trapezoidal waveforms, the threshold current was lowest for the 20-msec pulse but was not significantly different for the 5-20-msec pulses (p greater than 0.05). The threshold delivered energy was not significantly different for the 2.5-20-msec waveforms. The 40- and 55-msec pulses had significantly greater delivered energies than the shorter pulses (p less than 0.01). The transthoracic defibrillation threshold of two trapezoidal (5- and 20-msec) and three damped sine waves (Lown, Edmark, and Belfast) showed that the threshold transthoracic current and energy were not significantly different for the 5-msec trapezoid and three sine waves (p greater than 0.05). The threshold transthoracic energy for the 20-msec trapezoid was significantly greater than that of the four other waveforms. The threshold current for the 20-msec trapezoid was significantly less than that of the Belfast and Edmark waveforms only. Thus, none of the three damped sine waveforms was superior, with the 5-msec trapezoid producing similar results. Although the 20-msec trapezoid had the lowest threshold current, it had the highest delivery energy.

Animals↗
PubMed1989

Cardiac injury with damped sine and trapezoidal defibrillator waveforms.

To assess defibrillator-induced cardiac damage, 49 anaesthetized greyhounds received either no shocks (control group) or five shocks from a defibrillator delivering one of five waveforms (Lown, Edmark, Belfast damped sine waveforms: 5 and 20 ms trapezoidal waveforms). At 3 days the hearts of the 36 surviving dogs were examined for macroscopic damage. The Belfast and Edmark waveforms caused significantly more damage (mean 21.1 +/- SEM 2.9 g and 16.0 +/- 3.7 g) respectively than the Lown waveform (3.5 +/- 1.3 g) P less than 0.01. The 20 ms trapezoid caused significantly more damage (8.1 +/- 3.1 g) than the 5 ms pulse (0.7 +/- 1.3 g) P less than 0.05). The ventricular ectopic counts per minute were not significantly different in the three sine wave and 20 ms trapezoidal groups at 24 and 48 h (P greater than 0.05), but at 2 and 72 h were significantly greater in the Belfast and Edmark groups than in the Lown group (2 h, Belfast P less than 0.01, Edmark P less than 0.05: 72 h P less than 0.05). At 15 min there was more right chest ST-segment elevation in the Belfast than in the Lown, Edmark and 20 ms trapezoid groups (P less than 0.01), while left chest ST elevation was greater in the Belfast and Edmark than in the Lown (P less than 0.05) and 20 ms trapezoid groups (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effect of single-dose omeprazole on intragastric acidity and volume during obstetric anaesthesia.

Various antacid or antisecretory agents are used to reduce the risk to patients of aspiration of gastric contents during general anaesthesia and a trial of the gastric proton pump inhibitor, omeprazole, is reported here. Twenty women admitted for elective Caesarean section under general anaesthesia received a single 80-mg oral omeprazole dose at 2000 hours on the evening before surgery. Intragastric pH and volume were measured immediately after induction of anaesthesia and on completion of surgery. Eighty-five percent of pH measurements at induction and extubation and 80% and 95% of volume measurements at induction and extubation respectively met the defined success criteria (pH greater than or equal to 2.5, volume less than 25 ml). Omeprazole treatment was well tolerated by the women and Apgar scores and subsequent progress of the babies were acceptable. These results indicate that gastric acidity and volume were acceptable in the majority of women after omeprazole treatment, but the interval from drug administration to induction of anaesthesia may have been too long in some cases and resulted in unacceptably low pHs.

Adult↗
PubMed1989

Sources of stress and dissatisfaction among nurses in four hospital environments.

A study was designed to examine the hypothesis that occupational stress in nurses is a function of how they perceive their work environment. Sixty-five nurses on four mixed-sex wards were interviewed using a nursing stress and work environment scale. Demographic data including age, sex and nursing status were also collected. 'Work overload' and the 'death and dying' of patients were identified as the major sources of stress for all the nurses. In general, although there was little difference between the specialized and non-specialized groups of nurses in the degree of stress experienced, the work environments were found to be dissimilar. The reported level of dissatisfaction with their work environment combined with certain demographic characteristics were found significantly to predict the degree of stress experienced. These findings have implications for the organization of the ward and for the skills taught to nurses by which stress may be managed or alleviated.

Female↗