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Biomedical subjects

H Smith

Publications and source records attributed to H Smith.

At least 325 records · Page 18Linked to original sources
PubMed1989

Food intolerance and the irritable bowel syndrome.

Two hundred patients (156 women) with the irritable bowel syndrome were treated with dietary exclusion for three weeks. Of the 189 who completed this study, 91 (48.2%) showed symptomatic improvement. Subsequent challenge with individual foods showed that 73 of these 91 responders were able to identify one or more food intolerances and 72 remained well on a modified diet during the follow up period (mean (SD), 14.7 (7.98) months). Of the 98 patients who showed no symptomatic improvement after three weeks of strict exclusion only three were symptomatically well at follow up (mean (SD), 12.48 (8.09 months). There was no close correlation between response and symptom complex. There was a wide range of food intolerance. The majority (50%) identified two to five foods which upset them (range 1-14). The foods most commonly incriminated were dairy products (40.7%) and grains (39.4%).

Adolescent↗
PubMed1989

Correlation between blood eosinophilia and airways hyper-responsiveness in rats.

The injection of Sephadex particles intravenously into rats produced a specific blood eosinophilia and an hyper-responsiveness of the airways to 5-hydroxytryptamine (5-HT). The rats given Sephadex had an hyper-sensitivity to the respiratory effects of 5-HT in vivo with a shift to the left of the intravenous dose response curve. In vitro lung strips from rats given Sephadex were hyper-reactive to 5-HT in that the strips from these rats and control rats responded over the same dose range of 5-HT but the slope of the dose response curve and the maximum response were greater in the strips from the Sephadex treated rats. The levels of hyper-sensitivity in vivo and of hyper-reactivity in vitro both correlated with the numbers of blood eosinophils.

Animals↗
PubMed1989

Acute liver decompensation on withdrawal of cytotoxic chemotherapy and immunosuppressive therapy in hepatitis B carriers.

Five chronic carriers of hepatitis B virus developed a fulminant hepatitis-like picture when immunosuppression or cytotoxic treatment, given for unrelated disorders, was withdrawn. Viral replication at the time of the final illness was confirmed in three of the five cases by measurement of serum HBV DNA or the presence of HBc antigen on liver biopsy. A cytoplasmic and nuclear pattern of HBc was seen in histological material during life, but at post-mortem was limited to a nuclear distribution, suggesting greater destruction of hepatocytes containing cytoplasmic HBc. In two of the cases, chronic liver disease was found at post-mortem, there being no previous clinical or laboratory abnormality, but it is unlikely that this was a factor in the development of the superimposed fulminating hepatitis-like illness. Immunosuppressive and cytotoxic agents must be used with extreme caution in any hepatitis B carrier, as withdrawal can precipitate acute decompensation regardless of whether or not there is underlying chronic liver disease.

Adult↗
PubMed1989

The impact of alcohol on the acute hospital service: patient presentation, admission and the perception of alcohol use in such groups.

Patients presenting to an Emergency Department were assessed by a standard questionnaire and clinical examination as to the contribution that alcohol made to their presentation and the perception of their alcohol use. Patients under the influence of alcohol are more than twice as likely not to fill in simple questionnaires and not to perceive their alcohol consumption as different from non-drinking fellows. Emergency Departments are not the optimal site for the education and motivation of drinking patients to alter their future habits.

Alcohol Drinking↗
PubMed1988

Characterization of signal-sequence-coding regions selected from the Bacillus subtilis chromosome.

Signal-sequence-coding regions for protein export were selected from chromosomal Bacillus subtilis DNA. The number of different signals obtained was higher than expected on the basis of known exported proteins in B. subtilis. Most of the selected regions showed the characteristics of typical signal sequences, including a basic N-terminal region followed by a hydrophobic core and a potential signal-peptidase cleavage site. The signal-coding regions were functionally interchangeable between the B. licheniformis alpha-amylase and Escherichia coli TEM beta-lactamase genes. In addition to the signal-sequence-coding regions, the nature of the host cells, and the mature parts of the reporter proteins contributed to the amounts of protein secreted.

Amino Acid Sequence↗
PubMed1988

Treatment of patients with symptomless left ventricular dysfunction after myocardial infarction.

In a randomised, double-blind trial 60 patients with left ventricular dysfunction (ejection fraction less than 45%) but without clinical evidence of heart failure 1 week after Q wave myocardial infarction were given captopril 25 mg thrice a day, frusemide 40 mg daily, or placebo. Left ventricular volumes were measured at baseline and at 1, 3, 6, 9, and 12 months with cross-sectional echocardiography and Simpson's rule analysis of standardised apical views. The captopril group showed no significant change in left ventricular end-diastolic volume index but left ventricular end-systolic volume index was significantly reduced and stroke volume index and ejection fraction were significantly increased from 1 month on. In contrast, the frusemide and placebo groups showed significant increases in ventricular volumes, with stroke volume index unchanged and ejection fraction slightly reduced. The changes in the captopril group were significantly different from those in the other groups.

Adult↗
PubMed1988

Synthesis and processing of Escherichia coli TEM-beta-lactamase and Bacillus licheniformis alpha-amylase in E. coli: the role of signal peptidase I.

A mutant of Escherichia coli, in which signal peptidase I synthesis can be regulated, was constructed. The mutant was used to study the effects of signal peptidase I limitation on the synthesis and efficiency of processing of two proteins: the periplasmic E. coli TEM-beta-lactamase and Bacillus licheniformis alpha-amylase, which also accumulates in the periplasm of E. coli. Signal peptidase I limitation resulted in reduced rates of processing of pre-beta-lactamase and in strong inhibition of synthesis of alpha-amylase. The data suggest that beta-lactamase is processed post-translationally and that an intimate relationship exists between the synthesis and processing of alpha-amylase.

Bacillus↗
PubMed1988

Plutonium and americium uptake in rats fed with Cumbrian shellfish--implications for estimates of dose to man.

Winkles (Littorina littorea) and mussels (Mytilus edulis) collected on the Cumbrian coast contain americium-241 and isotopes of plutonium discharged from the nuclear-fuel reprocessing plant at Sellafield. Shellfish have been fed to rats and measurements made of the gastrointestinal absorption of the actinides. For shellfish collected over a 1-year period from March 1983 to February 1984, the average values for the fractional absorption of plutonium and americium were 9 x 10(-4) and 3 x 10(-4), respectively, for winkles and 1.5 x 10(-3) and 6 x 10(-4), respectively, for mussels. Comparisons with results for winkles collected in December 1981 and mussels collected in July 1982 suggest that there may be considerable seasonal variation in the availability of the actinides for absorption. The results suggest that in calculations of doses to individuals consuming shellfish in west Cumbria, it may be prudent to examine the effect of using the new ICRP gut transfer factor of 1 x 10(-3) for both actinides, in comparison with the value of 5 x 10(-4) recommended previously by NRPB. The use of 1 x 10(-3) would increase the estimate of the committed effective dose equivalent for 1985 intakes, from the value of 0.73 mSv calculated by the Ministry of Agriculture, Fisheries and Food, to 1.29 mSv. However, taking into account up-to-date estimates of the retention of the actinides in liver and bone would reduce this value to 1.07 mSv. If, in addition, allowance is made for the effect of the burial and recycling of actinides in bone, a significant reduction in the dose estimate could result; for example, the use of one proposed dynamic bone model would reduce the value from 1.07 to 0.54 mSv.

Americium↗
PubMed1988

Comparison of Visuwell enzyme immunoassay to culture for detection of group A Streptococcus in throat swab specimens.

A microwell enzyme immunoassay (Visuwell) for direct detection of Group A streptococcal antigen from throat swab specimens has been developed. It incorporates urease conjugated antibody as the detector and is easily interpreted by a yellow to purple color change. Throat specimens obtained on rayon-tipped swabs were transported moist in modified Stuarts medium and cultured before being tested in Visuwell (n = 585, prevalence 17.1%, sensitivity 88%, specificity 92.4%, predictive value positive 70.4%, predictive value negative 97.4%, and accuracy 91.6%). In instances of discrepancy between culture and Visuwell, throat swab extracts were tested in a latex agglutination test. In 21 of 37 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Throat specimens obtained using double rayon swabs and transported to the laboratory dry had one swab cultured and the other tested in Visuwell (n = 280, prevalence 20.4%, sensitivity 75.4%, specificity 88.3%, predictive value positive 62.3%, predictive value negative 93.4%, and accuracy 85.7%). When 1+ culture positive specimens were considered negative, a sensitivity of 97.6% was obtained. In 14 of 26 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Cross-reaction with organisms other than Group A Streptococcus found in the oropharynx was negligible in Visuwell. Limit of detection of Group A streptococcal antigen was equivalent for Visuwell and latex agglutination.

Adolescent↗
PubMed1988

Role of upper respiratory tract infection in the deaths occurring in neonatal ferrets infected with influenza virus.

Passive immunization of ferret neonates by colostrally-derived anti-influenza virus IgG did not entirely prevent infection when mothers were immunized with 1 or 2 doses of formalin inactivated vaccine with adjuvant (alhydrogel). Influenza virus replication was almost completely prevented in the lower respiratory tract but only slightly reduced in the upper respiratory tract leading to deaths in about 50% of the neonates. Such neonates showed at most only minor lesions in the lower respiratory tract but moderate to severe inflammatory changes in the upper respiratory tract of most animals. This supports previous results suggesting that deaths, reminiscent of the human sudden infant death syndrome (SIDS), may arise purely as a result of upper respiratory tract infection, possibly following obstruction of the airways.

Animals↗
PubMed1988

Cytidine 5'-monophospho-N-acetyl neuraminic acid and a low molecular weight factor from human blood cells induce lipopolysaccharide alteration in gonococci when conferring resistance to killing by human serum.

Recently evidence has been obtained that a minute amount of cytidine 5'-monophospho-N-acetyl neuraminic acid (CMP-NANA) or a closely related compound is the low Mr factor in human red blood cells which induces Neisseria gonorrhoeae (BS4(agar] to resistance to killing by fresh human serum. Induction of gonococci to resistance by both CMP-NANA and semi-purified low Mr factor from red blood cells was accompanied by a 35-55% reduction of silver staining of lipopolysaccharide separated in SDS-PAGE gels of proteinase K digests. These alterations in lipopolysaccharide are probably responsible for conferring serum resistance. However, lipopolysaccharide-containing digests from resistant as well as from susceptible gonococci neutralised serum bactericidal activity. These observations may have wider implications since CMP-NANA is a sialylating agent wide-spread in mammalian tissues and LPS is ubiquitous amongst Gram-negative pathogens.

Antibodies, Bacterial↗
PubMed1988

Cytidine 5'-monophospho-N-acetylneuraminic acid or a related compound is the low Mr factor from human red blood cells which induces gonococcal resistance to killing by human serum.

A low-Mr factor which induces gonococcal resistance to complement-mediated serum killing has been partially purified from lysates of mixed red and buffy coat cells from human blood. The lysates were dialysed against Tris buffer for 24 h at 25 degrees C with the diffusate being continuously recycled through a column of QAE-Sephadex A25. After elution in an NaCl gradient, the active fractions were both desalted and further purified on Sephadex G10. A second fractionation on QAE-Sephadex A25 and desalting with Sephadex G10 preceded further purification by repeated high-pressure liquid chromatography (HPLC) using a DEAE anion exchange column and desalting with Sephadex G10. Less than 500 micrograms of material showing one peak in HPLC was obtained from 1 litre of blood. After NMR had indicated the possible presence of pyrimidine nucleotide, carbohydrate and N-acetyl groups, nanogram quantities of a commercial preparation of cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NANA) were shown to induce gonococci to serum resistance. The synthetic CMP-NANA also co-eluted with the preparation from blood cells in HPLC, and the two materials were indistinguishable in their patterns of acid and heat lability. Furthermore, the resistance-inducing activity of both materials was inhibited by cytidine monophosphate, which is known to inhibit sialylation reactions by CMP-NANA. It appears therefore that the resistance-inducing factor is CMP-NANA or a closely related compound. If the factor is CMP-NANA, biological activities indicated that the cell lysate from 1 litre of blood contained about 40 micrograms, and the most purified preparation contained only about 1%. With this minute amount in a mixture, the presence of CMP-NANA or a closely related analogue could not be established unequivocally by NMR.

Blood Bactericidal Activity↗
PubMed1988

Protein changes associated with induced resistance of Neisseria gonorrhoeae to killing by human serum are relatively minor.

Serum-susceptible (SS) Neisseria gonorrhoeae were induced to resistance (SR) to complement-mediated killing by fresh human serum (FHS) by a small-Mr factor(s) from guinea-pig blood in 3 h at 37 degrees C, but not in the presence of bacteriostatic concentrations of chloramphenicol or neomycin, indicating that proteins mediated the acquisition of resistance. SDS-PAGE protein profiles of lysates of equal numbers of gonococci showed only two qualitative differences between SR and SS organisms, both in minor components (a protein A of about 205 kDa in the former and not the latter and vice versa for a protein B of about 16 kDa). Many proteins, however, including the three principal outer-membrane proteins, were present in larger amounts in SR gonococci. The lack of major changes in proteins when resistance is acquired was confirmed by immunoblotting the two protein profiles with the IgG of hyper-immune rabbit anti-SR and anti-SS sera, of rabbit anti-SR serum after absorption by SS organisms and of FHS used alone and after absorption with SS organisms. The IgM of FHS, which is responsible for most of the bactericidal activity, showed only faint reactions with a few proteins common to both SS and SR gonococci and no reactions when the FHS was absorbed with SS gonococci. This is in contrast to the strong and different reactions given with lipopolysaccharide (LPS) components of SS and SR organisms, which, prepared from the former organisms, neutralize the bactericidal activity of FHS. Hence, the relatively small protein changes accompanying induction are less likely to be directly responsible for serum resistance than the more profound LPS changes.

Bacterial Proteins↗
PubMed1988

Is perinatal mortality still a good indicator of perinatal care?

The increasing influence of very immature infants on perinatal mortality rates (PMR) led us to question the usefulness of this parameter in assessing perinatal care. To examine this further we have compared the incidence of perinatal asphyxia amongst mature babies (greater than or equal to 35 weeks gestation) for two geographically-defined populations of over 500,000 people. Both areas have a teaching hospital-based maternity service and comparable perinatal mortality rates. The incidence of severe post-asphyxial encephalopathy showed a marked excess in one population (1.93 vs 0.61 per 1000 births), which was not obviously explicable. Taken in conjunction with the figures for stillbirth in labour, this represented a 2.8 times greater risk for either fetal death in labour or severe asphyxial insult. It would appear that perinatal mortality rates do not accurately reflect important differences in those perinatal outcomes most likely to be affected by perinatal care.

Asphyxia Neonatorum↗