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Biomedical subjects

M C Smith

Publications and source records attributed to M C Smith.

At least 145 records · Page 8Linked to original sources
PubMed1992

An outbreak of hepatitis A in Gloucester, UK.

During an outbreak of hepatitis A that occurred in Gloucester, UK between September 1989 and January 1991, 162 clinical cases were identified through notifications and laboratory reports, a monthly attack rate of 1.05 per 10,000 residents. The highest attack rate was seen in 5-14-year-olds. There were significant correlations between hepatitis A attack rates in the electoral wards of Gloucester and with the Jarman UPA 8 scores for the wards and with overcrowding, unemployment, under 5-year-olds and ethnic minority. The use of human normal immune globulin prophylaxis (HNIG) for household contacts was unsuccessful in ending the outbreak, partly because only one third of cases reported a household contact with recent hepatitis A. Our experience does not support the use of HNIG in stopping community-wide outbreaks of hepatitis A. Two public health campaigns were mounted during the outbreak; both were followed by a fall in the number of cases. Greater priority should be given to the implementation and evaluation of public health campaigns in future community-wide outbreaks of hepatitis A.

Adolescent↗
PubMed1992

Parietal bone mobility in the anesthetized cat.

To quantify parietal bone motion in reference to the medial sagittal suture, a newly developed instrument was attached to the surgically exposed skull of anesthetized adult cats. The instrument differentiated between lateral and rotational parietal bone movements around the fulcrum of the suture. Bone movement was produced by external forces applied to the skull and by changes in intracranial pressure associated with induced hypercapnia, intravenous injections of norepinephrine, and controlled injections of artificial cerebrospinal fluid into the lateral cerebral ventricle. Responses varied considerably among test animals. Generally, lateral head compression caused sagittal suture closure, small inward rotation of the parietal bones, increased intraventricular pressure, transient apnea, and unstable systemic arterial blood pressure. Graded increases in intracranial volume produced stepped increases in pressure, lateral expansion at the sagittal suture, and outward rotation of the parietal bones. We attribute variations in animal response largely to differences in intracranial and suture compliance among them. Cranial suture compliance may be an important factor in defining total cranial compliance.

Animals↗
PubMed1991

Catalytic hydrogenolysis of poly-iodinated recombinant human insulin-like growth factor II (IGF-II): a potentially useful method for the tritiation of IGF-II.

A method has been developed to prepare, purify, and fully characterize poly-iodinated insulin-like growth factor II (IGF-II) which can then be catalytically deiodinated to produce IGF-II with its native disulfide bonded structure. This method can potentially be adapted to prepare tritiated IGF-II with the use of tritium gas in the hydrogenolysis step. IGF-II was iodinated at all three tyrosines using lactoperoxidase with a three-fold excess of sodium iodide. The iodinated products were purified using reversed-phase HPLC and characterized by peptide mapping. The tyrosine-containing peptides generated by pepsin digestion were characterized by amino acid sequence analysis. Mono- and di-iodinated phenylthiohydantoin tyrosine derivatives were synthesized and used to identify the iodination state of the modified tyrosine residues in the sequence analysis. Purified poly-iodinated IGF-II was deiodinated by hydrogenolysis, over a prereduced palladium (II) oxide catalyst to form IGF-II with its native disulfide bonds intact, as shown by peptide mapping.

Amino Acid Sequence↗
PubMed1991

Altered affinity of insulin-like growth factor II (IGF-II) for receptors and IGF-binding proteins, resulting from limited modifications of the IGF-II molecule.

The binding affinities of seven analogues of recombinant human insulin-like growth factor II (hIGF-II) were characterized for the IGF type-I and type-II receptors and insulin receptors, as well as for IGF-binding protein (IGFBP)-1, IGFBP-2, IGFPB-3 and human serum IGFBPs. A switch of two of the three cysteine bridges in hIGF-II, 9-47 and 46-51 to 9-46 and 47-51, severely impaired the binding of this analogue to all receptors and to the IGFBPs. The affinities for the IGF type-I receptor and the IGFBPs were decreased over 100-fold, while the binding to the insulin receptor and the IGF type-II receptor was less affected, with a 6-10-fold decrease in affinity. Slight modifications of the N-terminus had only minor effects upon the binding of hIGF-II to the IGFBPs or to the receptors. Deletion of both the N-terminal amino acid and the two C-terminal amino acids resulted in moderate decreases in affinity, with a 60% decrease in affinity for IGFBP-1 and the IGF type-I receptor. Acetylation of the N-terminus of Ala1 and the epsilon-nitrogen of Lys65 decreased the affinity, by 60-90%, of hIGF-II for all of the IGFBPs and receptors. The experiments involving acetylation of IGF-II or switching of its cysteine bridges indicated that these modifications (no substitution, deletion or addition of any of the 67 amino acids of hIGF-II) may lead to a severe impairment of the binding affinity of IGF-II for both the IGFBPs and the receptors. Acetylation of the epsilon-nitrogen of Lys65, which causes a charge change, or alteration of the three-dimensional structure, as shown by the cysteine bridge switch, lead to a severe impairment of the binding affinity for the binding proteins and for the receptors. In general, care should be taken with the synthesis of analogues and the interpretation of resulting binding data, since affinity alterations ascribed to amino acid changes may instead be caused by alterations of the charge or the three-dimensional structure of the protein.

Amino Acid Sequence↗
PubMed1991

Effects of second-codon mutations on expression of the insulin-like growth factor-II-encoding gene in Escherichia coli.

Expression plasmids encoding random sequence mutant proteins of insulin-like growth factor II (IGFII) were constructed by cassette mutagenesis, to improve the efficiency of IGFII synthesis in Escherichia coli. A pool of oligodeoxyribonucleotide linkers containing random trinucleotide sequences were used to introduce second-codon substitutions into the gene encoding Met-Xaa-Trp-IGFII in expression vectors. E. coli RV308 cells transformed with these vectors synthesized IGFII at levels varying from 0-22% of total cell protein. This variable synthesis is a function of the random second-codon sequence and its corresponding amino acid, Xaa. Our data showed that mRNA stability, protein stability and translational efficiency all contributed to variable expression levels of Met-Xaa-Trp-IGFII in E. coli. Furthermore, an efficiently synthesized IGFII mutant protein, Met-His-Trp-IGFII, was converted to natural sequence IGFII by a simple oxidative cleavage reaction.

Amino Acid Sequence↗
PubMed1991

A randomized, double-blind trial of prostaglandin E2 gel for cervical ripening and meta-analysis.

The ability of prostaglandin E2 to prepare the unripe cervix before an indicated labor induction is controversial. We therefore tested 100 pregnant women in a randomized, double-blind trial with intracervical prostaglandin E2 gel, 0.5 mg. The 53 women who received the placebo gel had an outcome similar to that of the 47 women who received the prostaglandin E2 gel. The mean change in cervical score, mean application-to-delivery interval, incidence of uncomplicated spontaneous labor, incidence of cesarean delivery for a failed induction, and the overall cesarean section rate were not significantly different for the two groups. A meta-analysis, incorporating 18 studies of 1811 patients who received a single application of at least 5 mg prostaglandin E2 gel intravaginally or 0.5 mg intracervically, demonstrated no significant decrease in the overall cesarean delivery rate (p = 0.85). We conclude that the use of single-dose intracervical prostaglandin E2 gel for cervical ripening has little effect on labor induction. Moreover, the use of single-dose intracervical or intravaginal prostaglandin E2 gel does not alter the incidence of cesarean delivery, even when large numbers of patients are analyzed by combining the results of similar reports.

Adult↗
PubMed1991

An outbreak of Legionnaires' disease in Gloucester.

Fourteen people living in or near the city of Gloucester fell ill with Legionnaires' disease caused by Legionella pneumophila serogroup (SG) 1 between 27 August and 27 October 1986. Another patient had fallen ill on 30 May. Nine of the 15 were diagnosed retrospectively during a case finding exercise. There were three deaths. Three cases of Pontiac fever were also diagnosed. The source was probably one or more wet cooling towers. Nineteen premises in the city with such towers were identified, and three just outside Gluocester. Samples from 11 of the 22 premises grew Legionella spp.; from nine of these L. pneumophila SG 1 (Pontiac) was isolated. The efficacy of regular addition of biocide in addition to hypochlorite added at the time of disinfection in inhibiting the growth of Legionella spp. was demonstrated. A survey of patients' movements during their likely incubation period showed that there was no single building that all patients had visited, but there were two areas of the city which nearly all had visited or passed through by car. A case-control study demonstrated an association with one of these areas. Cooling towers near both areas may have been sources but the evidence is insufficient to incriminate any single one. The unexpected finding of L. pneumophila SG 1 (Pontiac) in nine towers supports the hypothesis that there may have been multiple sources. Cooling towers may have been contaminated by mains water or by drift from other towers.

Adult↗
PubMed1991

Cough intensity in the laryngectomee.

The exact role or even the necessity for a functioning larynx in the production of an efficient cough is unknown. This study compares the cough intensity of 10 laryngectomees with a control group of 10 individuals with a larynx. There is no significant difference in the peak flow but the time taken to reach the peak flow is prolonged in the laryngectomees. The supramaximal expiratory flow is thus absent. The larynx is not essential for coughing although the different pattern may be less efficient. This simple test may have diagnostic value in assessing the larynx.

Aged↗
PubMed1991

A prototype for integrative review and meta-analysis of nursing research.

Meta-analysis has gained international recognition as a statistical approach to research synthesis. What is missing in research reviews, however, is the systematic compilation of results from non-experimentally designed studies. An approach is described which extends the rigours of integrative research review and meta-analysis to descriptive studies. A model for conceptualizing a systematically derived research synthesis is presented with selected accompanying generic elements. The model serves as a prototype for application to a variety of topical areas of interest. Generic elements contained in the prototype may be tailored to specific topics with relative ease. Resources and time required for topic development from conceptualization through to dissemination can be considerably reduced by adaptation of the generic elements.

Clinical Nursing Research↗
PubMed1991

The lessons of deafness: deafness awareness and communication skills training with medical students.

This paper describes a 1-day course on deafness awareness and communication skills with fourth-year medical undergraduates and summarizes their evaluation of the course. Deaf people commonly experience major communication difficulties with doctors. This course gives students an awareness of deafness (and of the insights deaf people can give to an understanding of communication)--the lessons of deafness--and challenges some critical assumptions in medical practice. Students are given personal experience of deafness and of the consequent powerlessness and loss of self-confidence, while also learning new communication skills which they then apply in a role-play consultation with a deaf patient. Systematic evaluation has been built into the programme and student opinion has been unanimously enthusiastic.

Clinical Competence↗
PubMed1991

Three in-frame N-terminally different proteins are produced from the repressor locus of the Streptomyces bacteriophage phi C31.

The sequence of the repressor locus, c, of the Streptomyces temperate phage, phi C31, was shown previously to contain an open reading frame encoding a 74 kDa protein. Further analysis of the transcriptional and translational products of the c gene shows a more complex pattern of expression. A nest of three in-frame N-terminally different, C-terminally identical proteins of 74, 54 and 42 kDa were found to be expressed from a corresponding nest of transcripts. The repressor proteins were produced in Escherichia coli and the 42 kDa protein was purified, verified by N-terminal sequencing, and used to raise antibody. The antibody cross-reacted in Western blots with the 74, 54 and 42 kDa proteins expressed in E. coli and Streptomyces lividans and from Streptomyces coelicolor phi C31 lysogens. Analysis of transcription of the c gene by S1 mapping and primer extension showed that the nest of transcripts encoding the repressor protein were induced after heat treatment of the cts locus (Sinclair and Bibb, 1989; this paper). Correspondingly, all three of the repressor proteins were induced. In addition to a promoter, cp1, which lies upstream of the 74 kDa open reading frame, the c locus contained at least one internal promoter, cp2, which transcribes DNA encoding the 54 and 42 kDa proteins. Transcripts initiating from cp3 were observed in RNA preparations from S. lividans containing the c gene deleted for cp1 and cp2, but gene fusions using DNA which should contain any putative promoting activity from this region transcriptionally fused to the xylE gene showed very low levels of expression of catechol 2,3 dioxygenase in S. lividans. The 74 kDa protein was not necessary for super-infection immunity. Data described here and current knowledge of the nature of other 'dual start' genes suggest a model for the regulation of lysis versus lysogeny in phi C31.

Bacteriophages↗
PubMed1991

Detection of respiratory syncytial virus in nasopharyngeal secretions by shell vial technique.

A shell vial technique was used to recover respiratory syncytial virus (RSV) from frozen nasopharyngeal specimens previously tested by rapid diagnostic methods. With specimens determined to be positive by direct fluorescence assay (DFA), the shell vial technique was at least as sensitive as conventional tissue culture (92 versus 90%). The majority of RSV isolates were detected within 16 h postinoculation, versus an average of 4.5 days by conventional techniques. Also, the shell vial method recovered RSV from 16 of 17 specimens (94%) which had previously tested positive by enzyme immunoassay (EIA). In addition, the shell vial method detected RSV in 4 and 11% of specimens previously determined to be negative by DFA and EIA, respectively. Therefore, we recommend the use of the shell vial technique for specimens testing negative by the rapid methods of DFA or EIA.

Child, Preschool↗
PubMed1991

Controlled study of heparin versus epoprostenol sodium (prostacyclin) as the sole anticoagulant for chronic hemodialysis.

We performed a controlled parallel study comparing the effects of heparin sodium to epoprostenol sodium (prostacyclin sodium, Flolan) during hemodialysis in 30 dialysis patients. Mean fiber bundle volume loss and dialyzer function were similar with both anticoagulation methods. Intradialytic symptoms occurred in 100% of the epoprostenol dialyses and 88% of the heparin dialyses, but only 10/325 epoprostenol and 3/374 heparin dialysis were discontinued prematurely because of symptoms. Long-term hemodialysis with epoprostenol is safe and effective. Epoprostenol may be a suitable alternative to heparin in some dialysis settings.

Adult↗