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Biomedical subjects

S Lloyd

Publications and source records attributed to S Lloyd.

At least 73 records · Page 4Linked to original sources
PubMed1998

Risk factors for enterococcal urinary tract infection and colonization in a rehabilitation facility.

BACKGROUND: We attempted to define the risk factors for urinary tract acquisition of enterococcus in a 155-bed rehabilitation facility in Southeastern Michigan by performing a prospective, case-controlled observational study. METHODS: All cases were identified from daily review of microbiologic records of urine culture results. All urinary isolates of enterococcus species, whether representing infection or colonization, were saved on agar plates for subsequent pulsed-field gel electrophoresis. Thirty-five percent of urinary tract isolates were due to enterococcal species compared with 5% to 15% in adjacent acute-care facilities. A control was defined as the next patient with a nonenterococcal urinary isolate. RESULTS: No differences were found between cases and controls with respect to age, sex, admitting diagnosis, voiding habits, symptoms, laboratory values, geographic location, caregivers, or urinary infection versus colonization. CONCLUSIONS: Prior antibiotic use was more frequent in the patients colonized or infected with enterococcal isolates (78% vs 41%). No evidence was found for a single clone of enterococcal isolates in our facility by DNA analysis, suggesting that the acquisition of enterococcus in the urinary tract was endogenous.

Adult↗
PubMed1998

Dopamine and nicotinic receptor binding and the levels of dopamine and homovanillic acid in human brain related to tobacco use.

Reports of a reduction in the risk of developing Parkinson's disease and Alzheimer's disease in tobacco smokers, together with the loss of high-affinity nicotine binding in these diseases, suggest that consequences of nicotinic cholinergic transmission may be neuroprotective. Changes in brain dopaminergic parameters and nicotinic receptors in response to tobacco smoking have been assessed in this study of autopsy samples from normal elderly individuals with known smoking histories and apolipoprotein E genotype. The ratio of homovanillic acid to dopamine, an index of dopamine turnover, was reduced in elderly smokers compared with age matched non-smokers (P<0.05) in both the caudate and putamen. Dopamine levels were significantly elevated in the caudate of smokers compared with non-smokers (P<0.05). However there was no significant change in the numbers of dopamine (D1, D2 and D3) receptors or the dopamine transporter in the striatum, or for dopamine D1 and D2 receptors in the hippocampus in smokers compared with non-smokers or ex-smokers. The density of high-affinity nicotine binding was higher in smokers than non-smokers in the hippocampus, entorhinal cortex and cerebellum (elevated by 51-221%) and to a lesser extent in the striatum (25-55%). The density of high-affinity nicotine binding in ex-smokers was similar to that of the non-smokers in all the areas investigated. The differences in high-affinity nicotine binding between smokers and the non- and ex-smokers could not be explained by variation in apolipoprotein E genotype. There were no differences in alpha-bungarotoxin binding, measured in hippocampus and cerebellum, between any of the groups. These findings suggest that chronic cigarette smoking is associated with a reduction of the firing of nigrostriatal dopaminergic neurons in the absence of changes in the numbers of dopamine receptors and the dopamine transporter. Reduced dopamine turnover associated with increased numbers of high-affinity nicotine receptors is consistent with attenuated efficacy of these receptors in smokers. A decrease in striatal dopamine turnover may be a mechanism of neuroprotection in tobacco smokers that could delay basal ganglia pathology. The current findings are also important in the interpretation of measurements of nicotinic receptors and dopaminergic parameters in psychiatric conditions such as schizophrenia, in which there is a high prevalence of cigarette smoking.

Age Factors↗
PubMed1998

MutY catalytic core, mutant and bound adenine structures define specificity for DNA repair enzyme superfamily.

The DNA glycosylase MutY, which is a member of the Helix-hairpin-Helix (HhH) DNA glycosylase superfamily, excises adenine from mispairs with 8-oxoguanine and guanine. High-resolution crystal structures of the MutY catalytic core (cMutY), the complex with bound adenine, and designed mutants reveal the basis for adenine specificity and glycosyl bond cleavage chemistry. The two cMutY helical domains form a positively-charged groove with the adenine-specific pocket at their interface. The Watson-Crick hydrogen bond partners of the bound adenine are substituted by protein atoms, confirming a nucleotide flipping mechanism, and supporting a specific DNA binding orientation by MutY and structurally related DNA glycosylases.

Adenine↗
PubMed1998

Lack of association between the dopamine D2 receptor gene allele DRD2*A1 and cigarette smoking in a United Kingdom population.

The dopamine D2 receptor gene contains a TaqI repeat fragment length polymorphism creating two alleles DRD2*A1 and DRD2*A2. It has been previously suggested that the lesser allele, DRD2*A1, is more prevalent in individuals who are susceptible to impulsive/addictive/compulsive behaviour, for example, alcoholics, polysubstance abusers and tobacco smokers. We genotyped a series of 104 smokers and 117 non smokers and compared the allele frequencies between the groups. A subset (n = 87) of the smoking population also completed the Classification of Smoking by Motives questionnaire and were given scores for five criteria that drive smoking: automatic, dependence, sedative, stimulant and indulgence. Another subset (n = 52) completed the Fagerstrom Tolerance Questionnaire and were given scores for nicotine dependence. We did not find any increase in allele A1 frequency when comparing smokers to non smokers. Furthermore, neither measure of dependence was affected by possession of the A1 allele; the only difference between DRD2*A1 bearing and DRD2*A2 homozygous individuals in terms of smoking motives was found in the scores for indulgence; the former having a moderately reduced score (by 17%, p < 0.05). We conclude that, in the individuals studied, the dopamine D2 receptor TaqI locus does not affect the drive to smoke. This may be caused by the locus being unrelated to impulsive/addictive/compulsive behaviour, the polymorphism being in linkage disequilibrium with another distinct locus or, alternatively, smoking may represent a behaviour that is not directly comparable to impulsive/addictive/compulsive behaviours previously associated with the DRD2*A1 allele.

Alleles↗
PubMed1998

Predictive validity of the emergency physician and global job satisfaction instruments.

OBJECTIVE: To evaluate the predictive validity of the Emergency Physician Job Satisfaction (EPJS) and Global Job Satisfaction (GJS) instruments. METHODS: Prospective mail survey of 223 Canadian emergency physicians (EPs) using a 42-item questionnaire, including 14 items evaluating their reasons for leaving emergency medicine (EM). Original (1990) EPJS and GJS scores were analyzed using 1-way ANOVA and Scheffe's test comparing the physicians who left EM with those still in their original jobs, and those who had left their original jobs but who stayed in EM. Mean scores on the 14 "reason for leaving" items were compared with scores from an earlier sample of U.S. physicians using a t-test for independent means. Criteria for statistical significance were set at alpha = 0.05 for all analyses. RESULTS: The response rate for the primary study questions was 99.1%. Of the respondents, 29.4% had left their original jobs, and 10.4% had left EM altogether. The GJS scores for the physicians who left EM were significantly different from those for the physicians who stayed (p = 0.004). The EPJS scores for the physicians who left EM were not significantly different from those for the physicians who stayed (p = 0.56). There was no significant difference in scores between the Canadian and U.S. physicians' reasons for leaving EM (all p-values > 0.05). Shiftwork scored the highest as a reason to leave EM. CONCLUSIONS: A low GJS score is associated with physicians' leaving EM, but not with changing jobs. The EPJS instrument was not associated with either outcome. Canadian and U.S. EPs place similar levels of importance on potential reasons for leaving EM.

Analysis of Variance↗
PubMed1998

Risk factors associated with human cystic echinococcosis in Florida, Uruguay: results of a mass screening study using ultrasound and serology.

Sonographic evidence of asymptomatic Echinococcus granulosus lesions in the liver was found in 156 of 9,515 persons in the Department of Florida, Uruguay. The sensitivity of ELISA and latex agglutination serology compared with ultrasound was 47.6% and 28.1%, respectively, and specificity was > 85%. There was a significant positive association between positive sonography and a personal history of previous but treated Echinococcus infection while those that were seropositive but ultrasound-negative were significantly more likely to have a personal history of infection or a history of infection in their family. Prevalence of infection increased significantly with age. There was no correlation between echinococcosis and dog ownership or home slaughter of sheep but offal disposal was important, with an increased prevalence of infection of 3.2%, 2.8%, and 3.1%, respectively, in persons feeding offal to dogs or burying or burning it compared with a prevalence of 0.8-1.5% in those using other methods of disposal. Almost half the population, when questioned, seemed to have sound knowledge about E. granulosus and described correct treatment of E. granulosus in dogs but this did not affect prevalence. There was a significant positive association between infection and the presence of a fenced fruit/vegetable garden and use of rural waters, particularly the cachimba (a small dam) and the aljibe (a cistern or tank) that collect rainwater from the ground surface and roofs, respectively.

Adolescent↗
PubMed1998

Use of sentinel lambs to survey the effect of an education programme on control of transmission of Echinococcus granulosus in South Powys, Wales.

In this article the effects of an education programme (area II) on transmission of Echinococcus granulosus from dogs to sheep in Wales and of substitution of the education programme by a 6-weekly anthelmintic control programme (area I) are compared with the situation in an area where no control interventions had occurred (area III). The education programme failed to prevent transmission of E. granulosus to sentinel lambs examined at 15 months of age, 6%, 4%, and 10% of which were infected in areas I, II, and III, respectively. Educational efforts did, however, show some positive effects; for example, significantly more farmers (87-98%) in areas I, II, and III used praziquantel to treat their dogs compared with 39% of farmers in a lowland area in the east of England where E. granulosus is absent. In particular, the interval between treatments of dogs was significantly shorter in areas targeted with education programmes, and 38% of farmers in area I treated dogs at a 4-6 week interval, as did 17% in area II and 10% in area III, compared with only 3% in the lowland area. Also, more dogs in Wales (65-88%) were treated at an interval of < or = 3 months, whereas most of the dogs in the lowland area (64%) were treated at intervals of > or = 6 months. The shorter treatment intervals with praziquantel may account for the significantly fewer positive coproantigen tests among dogs in area I (6.3%) and area II (5.6%) compared with area III (23.9%).

Adolescent↗
PubMed1997

Nicotinic and muscarinic cholinergic receptor binding in the human hippocampal formation during development and aging.

High-affinity nicotine, alpha-bungarotoxin (alpha BT) and muscarinic receptor binding was measured in the human hippocampal formation in a series of 57 cases aged between 24 weeks gestation and 100 years. Changes in nicotine receptor binding during development and aging were more striking than differences in alpha BT and muscarinic binding. Nicotine binding was higher at the late foetal stage than at any other subsequent time in all areas investigated. In the hippocampus a fall in binding then occurred within the first six months of life, with little or no subsequent fall during aging, whereas in the entorhinal cortex and the presubiculum the major loss of nicotine binding occurred after the fourth decade. alpha BT binding was significantly elevated in the CA 1 region, but in no other region of the hippocampus, in the late foetus, and there was also a fall in alpha BT binding in the entorhinal cortex during aging from the second decade. The modest changes in total muscarinic binding, which appeared to reflect those in M1 and M3 + 4 rather than M2 binding, were a rise in the entorhinal cortex between the foetal stage and childhood and a tendency for receptors to fall with age in the hippocampus and subicular complex. These findings implicate mechanisms controlling the expression of nicotinic receptors to a greater extent than muscarinic receptors in postnatal development and aging in the human hippocampus.

Adolescent↗
PubMed1997

Lignans and isoflavonoids in plasma and prostatic fluid in men: samples from Portugal, Hong Kong, and the United Kingdom.

BACKGROUND: Chinese men have lower incidences of prostate cancer compared to men from Europe and North America. Asians consume large quantities of soya, a rich source of isoflavanoids phyto-oestrogens and have high plasma and urinary levels of these compounds. The mammalian lignans, enterolactone and enterodiol, are another group of weak plant oestrogens and are derived from seeds, cereals and grains. Vegetarians have high plasma and urinary concentrations of lignans. METHODS: The concentrations lignans and isoflavonic phyto-oestrogens were determined by gas chromatography-mass spectrometry (GC-MS) in plasma and prostatic fluid from Portuguese, Chinese and British men consuming their traditional diets. RESULTS: In prostatic fluid the mean concentrations of enterolactone were 31, 162 and 20.3 ng/ml for Hong Kong, Portugal and Britain respectively. Very high levels of enterolactone (> 600 ng/ml) were observed in the prostatic fluid of some of the men from Portugal. High concentrations of equol (3270 ng/ml) and daidzein (532 ng/ml) were found in a sample of prostatic fluid from Hong Kong. Higher mean levels of daidzein were observed in prostatic fluid from Hong Kong at 70 ng/ml, compared to 4.6 and 11.3 ng/ml in samples from Portugal and Britain respectively. Mean levels of daidzein were higher in the plasma samples from Hong Kong (31.3 ng/ml) compared to those from Portugal (1.3 ng/ml) and Britain (8.2 ng/ml). In general, the mean plasma concentrations of enterolactone from the three centres were similar, at 6.2, 3.9 and 3.9 ng/ml in samples from Hong Kong Portugal and Britain respectively. CONCLUSIONS: Higher concentrations of the isoflavanoid phyto-oestrogens, daidzein and equol, were found in the plasma and prostatic fluid of men from Hong Kong compared to those from Britain and Portugal. However, the levels of the lignan, enterolactone, were very much higher in prostatic fluid of Portuguese men. Isoflavanoids and lignans have many interesting properties and may, in part, be responsible for lower incidences of prostate cancer in men from Asia and also some Mediterranean countries. The isoflavanoids from soya, which are present in high concentrations in the prostatic fluid of Asian men, may be protective against prostate disease.

4-Butyrolactone↗
PubMed1997

Measurement and metabolism of isoflavonoids and lignans in the human male.

Asian men, who consume a low fat/high fibre soya-based diet, have very much lower incidence of prostate cancer than men from North America and Europe. The soya bean is a rich source of the isoflavonic phyto-oestrogens, daidzein, genistein and equol, compounds which may be cancer-protective in Asian populations. The lignans, enterolactone and enterodiol, plant oestrogens derived from cereals and vegetables, may act in a similar manner in vegetarian men. We report here on the measurement of isoflavonoids and lignans, by gas chromatography-mass spectrometry, in prostatic fluid of men from Asia and Europe and also on the metabolism of these compounds in Western men following dietary supplementation.

Adult↗
PubMed1997

Pattern of Cryptosporidium parvum oocyst excretion by experimentally infected dogs.

Six 6-week-old Beagle dogs were fed Cryptosporidium parvum oocysts of calf origin. All 6 dogs shed oocysts in faeces. Greater numbers of oocysts were detected with a Weber concentration technique (formalin-ethyl acetate extraction and NaCl centrifugal flotation) stained with either fluorescent antibody or modified Ziehl-Neelsen than with other formalin-ether or -ethyl acetate extraction methods. Oocyst numbers g-1 of faeces rose from days 3 to 5 to a first and highest peak lasting to days 7-9, and 5 of the 6 dogs passed oocysts for at least 80 days. However, the numbers of oocysts detected in the dogs' faeces were low, only 16.1% of the samples in the first month after infection and 2.5% thereafter contained > or = 10000 oocysts g-1 of faeces. Oocyst production was cyclical, with 19.3% of samples negative in the first month after infection and 42.5% thereafter.

Animals↗
PubMed1997

Nicotinic receptor distribution in the human thalamus: autoradiographical localization of [3H]nicotine and [125I] alpha-bungarotoxin binding.

The thalamus plays a major role in relaying and transforming information that is relayed to the cortex and in turn modulates cortical outputs. The reticular nucleus projects to the other thalamic nuclei, modulating and integrating their activity. The distribution of high affinity nicotine and alpha-bungarotoxin (alpha BTX) receptors in the human thalamus has been investigated by radioligand autoradiography in post mortem human tissue. [3H]nicotine binding in the human thalamus was high in most thalamic nuclei, especially in the lateral dorsal, the medial geniculate, lateral geniculate and anterior nuclei. The distribution of [125I] alpha BTX binding was quite distinct from [3H]nicotine binding. [125I] alpha BTX binding was generally lower (< 0.26-11.62 fmol/mg protein compared with 6.68-36.17 fmol/mg protein for nicotine binding) and concentrated in the reticular nucleus, with discrete groups of cells displaying higher binding in the latter. These results indicate differences between the distribution of nicotinic receptors in humans and those previously reported in mice and monkeys. Changes in high affinity nicotine and alpha BTX receptors in the thalamus may contribute to symptoms observed in neuropathological conditions associated with disorders of perception and movement such as Dementia with Lewy Bodies, Alzheimer's Disease and Schizophrenia.

Adult↗
PubMed1997

D2 dopamine receptor gene (DRD2) Taq1 A polymorphism: reduced dopamine D2 receptor binding in the human striatum associated with the A1 allele.

The relationship between a dopamine D2 receptor genetic polymorphism at the Taq1 A locus and the level of D2 receptor binding was investigated in normal, middle aged to elderly subjects with no psychiatric or neurological disorders. D2 receptor binding was measured by autoradiography in the caudate, putamen and nucleus accumbens, using the specific D2 receptor ligand [3H]-raclopride. In a sample of 44 individuals, only one was homozygous for the A1 allele, 25 were homozygous for A2 and 18 were heterozygotes. The presence of one or two A1 alleles was associated with reduced D2 receptor binding in all areas of the striatum, reaching statistical significance in the ventral caudate and putamen (p = 0.01 and p = 0.044, respectively). This reduction was more marked in males than females, particularly in the putamen. A genetic predisposition to lower D2 receptor expression may increase susceptibility to neuroleptic medication or clinical symptoms that are associated with diseases involving dopaminergic pathology.

Aged↗
PubMed1997

Widespread geographic distribution of oral Candida dubliniensis strains in human immunodeficiency virus-infected individuals.

Candida dubliniensis is a recently identified chlamydospore-positive yeast species associated with oral candidiasis in human immunodeficiency virus (HIV)-infected (HIV+) patients and is closely related to Candida albicans. Several recent reports have described atypical oral Candida isolates with phenotypic and genetic properties similar to those of C. dubliniensis. In this study 10 atypical chlamydospore-positive oral isolates from HIV+ patients in Switzerland, the United Kingdom, and Argentina and 1 isolate from an HIV-negative Irish subject were compared to reference strains of C. albicans and Candida stellatoidea and reference strains of C. dubliniensis recovered from Irish and Australian HIV+ individuals. All 11 isolates were phenotypically and genetically similar to and phylogenetically identical to C. dubliniensis. These findings demonstrate that the geographical distribution of C. dubliniensis is widespread, and it is likely that it is a significant constituent of the normal oral flora with the potential to cause oral candidiasis, particularly in immunocompromised patients.

AIDS-Related Opportunistic Infections↗
PubMed1997

Decreased [3H]ouabain binding sites in skeletal muscle of rats with chronic heart failure.

Abnormalities intrinsic to skeletal muscle are thought to contribute to decrements in exercise capacity found in individuals with chronic heart failure (CHF). Na+-K+-adenosinetriphosphatase (the Na+ pump) is essential for maintaining muscle excitability and contractility. Therefore, we investigated the possibility that the number and affinity of Na+ pumps in locomotor muscles of rats with CHF are decreased. Myocardial infarction (MI) was induced in 8 rats, and a sham operation was performed in 12 rats. The degree of CHF was assessed approximately 180 days after surgery. Soleus and plantaris muscles were harvested, and Na+ pumps were quantified by using a [3H]ouabain binding assay. At the time of muscle harvest, MI and sham-operated rats were similar in age (458 +/- 54 vs. 447 +/- 34 days old, respectively). Compared with their sham-operated counterparts, MI rats had a significant amount of heart failure, right ventricular-to-body weight ratio was greater (48%), and the presence of pulmonary congestion was suggested by an elevated lung-to-body weight ratio (29%). Left ventricular end-diastolic pressure was significantly increased in the MI rats (11 +/- 1 mmHg) compared with the sham-operated controls (1 +/- 1 mmHg). In addition, mean arterial blood pressure was lower in the MI rats compared with their control counterparts. [3H]ouabain binding sites were reduced 18% in soleus muscle (136 +/- 12 vs. 175 +/- 13 pmol/g wet wt, MI vs. sham, respectively) and 22% in plantaris muscle (119 +/- 12 vs. 147 +/- 8 pmol/g wet wt, MI vs. sham, respectively). The affinity of these [3H]ouabain binding sites was similar for the two groups. The relationship between the reduction in Na+ pump number and the reduced exercise capacity in individuals with CHF remains to be determined.

Animals↗
PubMed1996

Universal Quantum Simulators

Feynman's 1982 conjecture, that quantum computers can be programmed to simulate any local quantum system, is shown to be correct.

Journal Article↗