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Biomedical subjects

C M Murphy

Publications and source records attributed to C M Murphy.

At least 19 recordsLinked to original sources
PubMed1992

Mass balance strategy for protein sequencing. Application to a protein with an extended DNPNNP repeating motif.

The value of the mass balance strategy is illustrated in the sequence determination of S. aureus V8 protease. Capillary electrophoresis, electrospray mass spectrometry, and high performance tandem mass spectrometry are used as well as proteolysis and Edman degradation. The carboxy terminus is found to contain 17 irregularly repeating units of the triptych motifs NNP and DNP, which provide a challenge to any strategy involving mapping, sequencing, and overlapping of hydrolytic peptides.

Amino Acid Sequence↗
PubMed1992

An assessment of the thermogenic effects of fluoxetine in obese subjects.

Fluoxetine is an antidepressant drug with weight reducing properties. To assess whether fluoxetine has an ability to promote diet induced thermogenesis (DIT), 30 obese subjects (BMI 30-45 kg/m2) underwent a double blind, randomized, cross-over trial of 60 mg fluoxetine versus placebo. A two week single blind, run-in period on placebo was incorporated into the study to allow for placebo responders. The first stage of the study lasted for 14 days followed by a six week cross-over wash-out phase and concluded with the second 14 day stage of the study. An estimate of resting metabolic rate (RMR) was measured by continuous indirect calorimetry using the ventilated hood technique. Metabolic measurements were performed on six occasions, immediately before the first tablet was taken in the first stage, 24 hours after the first tablet was consumed and on the last day of the first stage; these three recordings were repeated on the second stage of the study. On each occasion a control reading of RMR was taken for 30 minutes then DIT was measured for 90 minutes following a lemon and glucose drink (1 g/kg body weight). Whilst a significant weight reduction (1.16 kg, P less than 0.05) occurred in the active stage, no such effect was achieved in the placebo phase. No differences were found between the two stages with regard to RMR, total DIT, peak DIT and time taken to reach peak DIT. We conclude that fluoxetine does not stimulate metabolism and that the weight reduction after 14 days therapy is due to other mechanisms.

Adult↗
PubMed1992

Adiposity in children: is mental retardation a critical variable?

Several authors have suggested that obesity is more prevalent amongst children with mental retardation than non-mentally retarded children. However, studies on which this suggestion is based typically lack adequate control groups. The current research compared adiposity amongst mentally retarded versus non-mentally retarded children. Study 1 compared 110 mentally retarded children with 107 non-mentally retarded children (162 males, 61 females; age range 11 months-20 years). The independent (predictor) variables included IQ and mental retardation. Dependent (criteria) variables were BMI and age-corrected BMI. Study 2, using the National Health and Nutrition Examination Survey-II data bank compared 20 children with reported mental retardation with 4015 control children on three variables: BMI, age-corrected BMI, and subscapular to triceps skinfold ratio. Results of both studies found no significant difference in adiposity or body fat distribution between mentally retarded and non-mentally retarded children. Moreover, no significant difference emerged when either age or gender were controlled and no curvilinear or interaction effects were observed.

Adipose Tissue↗
PubMed1992

Risk classification of life and health insurance applicants with atypical melanocytic hyperplasia or malignant melanoma in situ.

Physicians may attempt to disguise malignant melanoma in situ from insurance companies by diagnosing atypical melanocytic hyperplasia instead. This study indicates that the insurance industry is not misled by atypical melanocytic hyperplasia and treats it equivalently to malignant melanoma in situ. In addition, physicians' failure to diagnose malignant melanoma in situ may result in underestimation of the incidence of malignant melanoma and may cause inadequate initial treatment and patient follow-up.

Humans↗
PubMed1992

Asthma in children.

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Adrenal Cortex Hormones↗
PubMed1991

Primary structure of molluscan metallothioneins deduced from PCR-amplified cDNA and mass spectrometry of purified proteins.

The primary structure of metallothioneins (MT) of a mollusc, the oyster Crassostrea virginica, was determined by molecular cloning and mass spectrometry of purified proteins. The cloning strategy included PCR amplification of the responsible cDNAs from total cDNA using completely degenerate oligonucleotides (derived from the N-terminal amino acid sequence) and oligo(dT)20 as primers. Primer extension off mRNA was used as an independent determination of the nucleotide sequence represented by the degenerate PCR primers. The deduced amino acid sequence was consistent with characteristics of class I MT. Twenty-one cysteine residues, were arranged in nine Cys-X-Cys motifs, five as Cys-Lys-Cys. A single Cys-X-X-Cys motif was also observed. Two MTs that differ only in the presence or absence of an N-acetyl group exist in this organism. Masses of tryptic peptides of purified MTs corresponded with those of peptides predicted from tryptic cleavages of the deduced amino acid sequence. Allowing for known N-terminal modifications, 96% of the deduced sequence was confirmed by mass spectrometry. Comparison (FASTA algorithm) of the primary structure of the oyster MTs with those of other species indicated a higher similarity with vertebrate MTs than with those of other invertebrates.

Amino Acid Sequence↗
PubMed1991

Structure and time-dependent behavior of acetylated and non-acetylated forms of a molluscan metallothionein.

Cadmium-induced metallothionein in a mollusc, the oyster Crassostrea virginica, occurs in both blocked and unblocked forms (Roesijadi, G., Kielland, S.L. and Klerks, P. (1989) Arch. Biochem. Biophys. 273, 403-413). The block, which is the sole difference in the structure of the two proteins, was identified as an acetyl group with use of tandem mass spectrometry. The blocked and unblocked proteins carried N-acetylserine and serine, respectively, at the N-terminus and were designated CvNAcMT and CvMT. Only CvNAcMT was detected under basal conditions. Both forms were induced by Cd. Pulse-labeling with [35S]cyteine at specified times during exposure showed that the rate of CvNAcMT synthesis in gills increased rapidly, initially exceeding that of CvMT, then declined to the rate attained by CvMT. Turnover rates for Cd-induced CvMT and CvNAcMT were similar to each other. They appeared to be faster when measured in the absence of Cd in the external medium (k = 0.18 and 0.16/day, respectively), than in its presence (k = 0.03 and 0.06/day, respectively).

Acetylation↗
PubMed1991

Treatment of asthma in children.

The epidemiology, etiology and pathophysiology, clinical presentation and diagnosis, and drug therapy of asthma in children are reviewed. Recent advances in drug therapy have, for unknown reasons, been accompanied by an increase in the morbidity and mortality associated with childhood asthma. The cause of asthma is not precisely understood, but an inflammatory process and hyperactivity of airways are common findings in the disease. Asthma in children can be classified as intermittent, chronic, or indeterminate; a severe, prolonged episode not relieved by usual treatment is called status asthmaticus. The hallmark symptoms of asthma are coughing, dyspnea, and wheezing. Beta-adrenergic agonists can be used orally for diagnostic purposes or for nocturnal asthma; i.v. or s.c. for emergency treatment; or by inhalation for relief of acute asthmatic episodes. Experience with anticholinergics in children is limited, and these agents should be used only when other options have failed. Inhalation of cromolyn sodium is very safe and is useful for the prophylactic treatment of mild to moderate asthma. Corticosteroids, which are used both for acute asthmatic episodes and for long-term treatment, can be given orally, i.v., or by inhalation. Theophylline is used for prophylactic therapy in children with chronic asthma. Selection of a drug regimen is based on knowledge of efficacy, pharmacokinetics, compliance, and toxicity. The treatment of asthma in children requires consideration of drug properties in young patients. Drugs used to treat childhood asthma include beta agonists, anticholinergics, cromolyn sodium, corticosteroids, and theophylline.

Administration, Inhalation↗
PubMed1991

Marital adjustment, parental disagreements about child rearing, and behavior problems in boys: increasing the specificity of the marital assessment.

2 studies were conducted to illustrate how measuring a specific aspect of marriage, namely, child-rearing disagreements, provides a better understanding of the link between marriage and boys' behavior. In Study 1, 200 mothers of 3-year-old boys completed unstandardized measures of marital functioning and child behavior. An index of child-rearing disagreements: (1) correlated with a greater variety of behavior problems than nonchild disagreements, and (2) improved upon the prediction of behavior problems after accounting for nonchild disagreements as well as after accounting for boys' exposure to marital conflict. In Study 2, 87 mothers with 4-6-year-old sons completed the index of child-rearing disagreements used in Study 1 as well as standard measures of marital functioning and child behavior. Child-rearing disagreements: (1) predicted a greater variety of behavior problems than global marital adjustment, and (2) improved upon the prediction of internalizing problems after controlling for global marital adjustment as well as after controlling for boys' exposure to marital conflict.

Adaptation, Psychological↗
PubMed1990

Recognition of trypsin autolysis products by high-performance liquid chromatography and mass spectrometry.

Potential artifactual contributions are assessed in high-pressure liquid chromatograms and fast atom bombardment mass spectra from autolysis of different preparations of the widely used protease trypsin. Both commercially supplied and laboratory-purified samples were examined. Bovine pancreatic trypsin (1 mg/mL) was found to be completely destroyed in 2 h at pH 8.5, degraded to a complex mixture of small peptides which were characterized by their molecular weights. Some identifications were supported by sequencing by tandem mass spectrometry or by mass spectrometric analysis of the mixture resulting from a single Edman degradation. Autolysis of porcine pancreatic trypsin produced a completely different set of peptides. Five sites of hydrolysis at asparagine residues in bovine trypsin were also identified.

Amino Acid Sequence↗
PubMed1989

Acetoacetyl-acyl carrier protein synthase. A target for the antibiotic thiolactomycin.

The biochemical basis for the inhibition of fatty acid biosynthesis in Escherichia coli by the antibiotic thiolactomycin was investigated. A biochemical assay was developed to measure acetoacetyl-acyl carrier protein (ACP) synthase activity, a recently discovered third condensing enzyme from E. coli (Jackowski, S., and Rock, C.O. (1987) J. Biol. Chem. 262, 7927-7931). In contrast to the other two condensing enzymes in E. coli, acetoacetyl-ACP synthase (synthase III) condensed malonyl-ACP with acetyl-CoA, rather than with acetyl-ACP. The concentration dependence of thiolactomycin inhibition of fatty acid biosynthesis in vivo was the same as the inhibition of acetoacetyl-ACP synthase activity in vitro indicating that the two phenomena were related. A thiolactomycin-resistant mutant (strain CDM5) was isolated. The specific activity of acetoacetyl-ACP synthase in extracts from this mutant was 10-fold lower than in extracts from its thiolactomycin-sensitive parent resulting in a marked defect in the ability of strain CDM5 to incorporate acetyl-CoA into fatty acids in vitro. The residual acetoacetyl-ACP synthase activity in the resistant strain was refractory to thiolactomycin inhibition. In addition, acetyl-CoA:ACP transacylase activity in strain CDM5 was resistant to inactivation by thiolactomycin suggesting that the acetoacetyl-ACP synthase also catalyzes this transacylation reaction. These data point to acetoacetyl-ACP synthase as a target for thiolactomycin inhibition of bacterial fatty acid biosynthesis.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed1989

A micro-kininogenase assay for studies of kallikrein in renal micropuncture/microperfusion.

We report the development of a micro-kininogenase assay suitable in studying the dynamics of kallikrein at intranephron segmental level. The detection limit is 119 fg or 2.6 attomoles of kallikrein. Activation of microquantities of kallikrein is possible with the use of Triton X-100. Because of its extremely high sensitivity and reproducibility the assay is likely to also prove useful in physiological studies in which only very small amounts of kallikrein containing samples can be obtained.

Animals↗
PubMed1989

Effects of maternal mood on mother-son interaction patterns.

This study evaluated the impact of maternal mood on mother-son interaction patterns. Forty boys between the ages of 46 and 72 months and their mothers participated. A within-subject experimental design was employed so that all mothers participated in both a positive and a negative mood induction. Observations of mother-son interactions were conducted immediately following the mood inductions. During the negative mood condition, mothers issued fewer positive statements toward their children and engaged in less general verbal interaction. In addition, children were less complaint with maternal commands during the negative mood condition. Implications of the effects of mood on mother-child interaction patterns are discussed.

Adult↗
PubMed1989

Interspousal aggression, marital discord, and child problems.

The association between interspousal aggression and child problems was assessed after controlling for parents' general marital discord. Participants were 87 couples requesting marital therapy who had children between 5 and 12 years old. Spouses completed measures of marital aggression, marital discord, child problems, and family demographics. Marital aggression contributed unique variance to the prediction of conduct disorder, personality disorder, inadequacy-immaturity, and clinical levels of problematic child behavior after marital discord, child's age, child's sex, and Marital Discord X Child's sex interaction were controlled. The theoretical implications of these findings are discussed.

Adult↗
PubMed1989

Psychological aggression predicts physical aggression in early marriage.

Psychological aggression by self and partner, physical aggression by the partner, and marital dissatisfaction were examined as longitudinal predictors of first instances of physical aggression during marriage. Subjects who were not physically aggressive at a premarital assessment were selected from a sample of 393 engaged couples. Couples participated in three subsequent assessments over the first 30 months of marriage. As hypothesized, individuals' own psychological aggression predicted their initial incidents of physical aggression in marriage. Psychological aggression by their partners also predicted initial incidents of physical aggression. Prior physical aggression by their partners was inconsistently associated with first instances of physical aggression. Contrary to our hypothesis, previous levels of marital dissatisfaction did not predict initial incidents of physical aggression. These findings were consistent across sexes. The results underscore the progression from psychological to physical abuse and have clear implications for understanding the development and prevention of interspousal aggression.

Adult↗
PubMed1989

Clearance of beta-2-microglobulin using continuous ambulatory peritoneal dialysis.

In the 9 continuous ambulatory peritoneal dialysis (CAPD) patients studied, the mean clearance of beta 2-microglobulin was significantly higher using hypertonic as opposed to isotonic exchanges (1 ml/min and 0.75 ml/min, respectively). Clearance of beta 2-microglobulin correlated with the clearance of albumin. The daily mass transfer of beta 2-microglobulin ranged from 19 to 62 mg. Although all the daily production of beta 2-microglobulin is not eliminated in patients on CAPD their serum beta 2-microglobulin levels would be expected to be lower than in patients on haemodialysis. Long-term prospective studies are needed to determine whether lower serum beta 2-microglobulin levels lead to a lower incidence of dialysis amyloid.

Ascitic Fluid↗