Clinical neurochemistry: developments in dementia research based on brain bank material

Brain tissue obtained at autopsy continues to provide unique opportunities in current dementia research. Not only is tissue analysis still essential for diagnosis, but investigation of neurochemical pathology, at a level of resolution beyond current in vivo imaging, continues to provide new insights into the involvement of neurotransmitter signalling systems. These are relevant to therapy which, with respect to symptoms such as cognitive impairment, psychosis and depression, is currently targeted to specific transmitter (cholinergic, dopaminergic and serotonergic) systems. This paper focuses on dopaminergic, cholinergic and histaminergic parameters in Alzheimer's disease (AD), Dementia with Lewy bodies (DLB) and Parkinson's disease (PD). In the normal striatum the dopamine transporter and D2 receptor exhibit distinct rostral-caudal distributions and D2 binding is affected by genetic polymorphism at the Taq 1A locus. The transporter is reduced in both DLB and PD but not AD, correlating with severity of extrapyramidal dysfunction, and receptor abnormalities are apparent in DLB patients responding adversely to neuroleptics. Striatal nicotine receptors are lost in all 3 disorders, further reduced as a result of neuroleptic medication, and elevated as a result of tobacco use. In the thalamus there are selective reductions in presynaptic cholinergic activity in DLB in the reticular nucleus which relate to symptoms of hallucinations and fluctuating consciousness prevalent in this disorder. In the hippocampus coupling of muscarinic M1 receptors, relevant to response to cholinergic therapy, is impaired in areas most affected by beta-amyloid plaques and intact in less affected areas. Analysis of histamine H2 receptors indicates that, despite presynaptic histamine abnormalities in AD, receptor numbers are normal. Such clinically and therapeutically relevant observations on human brain neurochemistry provide a basis for improving therapeutic strategies and prospects of diagnostic in vivo chemical imaging.

Expression of the alpha3 nicotinic receptor subunit mRNA in aging and Alzheimer's disease

Changes in the number of high-affinity nicotine binding sites have been widely reported in specific regions of the human brain during aging and in degenerative neurological diseases associated with aging, such as Alzheimer's disease. Nicotinic receptors are highly diverse and a description of the molecular subtypes affected in such conditions has not been achieved to date. To investigate the status of the alpha3 subunit-containing subtypes in such conditions, we assessed by in situ hybridisation the alpha3 mRNA density in the hippocampus, entorhinal cortex and thalamus of Alzheimer's patients and age-matched controls. No significant difference in the expression of the alpha3 mRNA, either qualitative or quantitative, was found between Alzheimer's individuals and controls in any of the analysed areas. This result suggests that the nicotine binding changes occurring in these areas in Alzheimer's patients are not correlated to a variation of the alpha3 mRNA in the same regions. Nevertheless, a negative correlation between the alpha3 mRNA density and the age was observed in the entorhinal cortex of both the Alzheimer's and the normal subjects, suggesting a potentially extensive decay of the alpha3-expressing neurons or loss of alpha3-containing receptors in intact neurons of the entorhinal cortex in the late elderly.

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.

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.

Nigrostriatal dopaminergic activities in dementia with Lewy bodies in relation to neuroleptic sensitivity: comparisons with Parkinson's disease

BACKGROUND

In dementia with Lewy bodies (DLB) mild extrapyramidal symptoms are associated with moderate reductions in substantia nigra neuron density and concentration of striatal dopamine. Many DLB patients treated with typical neuroleptics suffer severe adverse reactions, which result in decreased survival.

METHODS

In a series of DLB cases, with and without neuroleptic sensitivity, substantia nigra neuron densities, striatal dopamine and homovanillic acid concentrations, and autoradiographic [3H]mazindol and [3H]raclopride binding (to the dopamine transporter and D2 receptor, respectively) were analyzed and compared to control and idiopathic Parkinson's disease cases.

RESULTS

D2 receptors were up-regulated in neuroleptictolerant DLB and Parkinson's disease compared to DLB without neuroleptic exposure and controls. D2 receptors were not up-regulated in DLB cases with severe neuroleptic reactions. Dopamine uptake sites were reduced concomitantly with substantia nigra neuron density in Parkinson's disease compared to controls, but there was no significant correlation between substantia nigra neuron density and [3H]mazindol binding in DLB groups. There was no significant difference in substantia nigra neuron density, [3H]mazindol binding, and dopamine or homovanillic acid concentration between neuroleptic-tolerant and -sensitive groups.

CONCLUSIONS

Failure to up-regulate D2 receptors in response to neuroleptic blockade or reduced dopaminergic innervation may be the critical factor responsible for neuroleptic sensitivity.

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.

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.

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.

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.

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%).

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.

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.

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.

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.

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.

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.

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.

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.

Universal Quantum Simulators

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

Familial breast cancer: a controlled study of risk perception, psychological morbidity and health beliefs in women attending for genetic counselling

The present study set out to evaluate perceptions of risk, psychological morbidity and health behaviours in women with a family history of breast cancer who have attended genetic counselling and determine how these differ from general population risk women. Data were collected from 62 genetic counselees (cases) attending the Royal Marsden and Mayday University Hospital genetic counselling services and 62 matched GP attenders (controls). Levels of general psychological morbidity were found to be similar between cases and controls; however, cases reported significantly higher breast cancer-specific distress despite clinic attendance [mean (s.d.) total Impact of Event Scale score, 14.1 (14.3) cases; 2.4 (6.7) controls, P < 0.001]. Although cases perceived themselves to be more susceptible to breast cancer, many women failed correctly to recall risk figures provided by the clinic; 66% could not accurately recall their own lifetime chance. Clinics appeared to have a positive impact on preventive behaviours and cases tended to engage more regularly in breast self-examination (monthly, 66% of cases vs 47% of controls), although few differences were found between groups in terms of health beliefs. We conclude that counselees and GP controls showed considerable similarities on many of the outcome measures, and risk of breast cancer was not predictive of greater psychological morbidity; although cases were more vulnerable to cancer-specific distress. Despite genetic counselling, many cases continued to perceive their risk of breast cancer inaccurately.

Validation of the functional assessment of multiple sclerosis quality of life instrument

Based on scientific literature and interviews with clinicians and patients, we developed a quality of life instrument for use with people with MS called the Functional Assessment of Multiple Sclerosis (FAMS). The initial item pool consisted of 88 questions: 28 from the general version of the Functional Assessment of Cancer Therapy quality of life instrument, plus 60 generated by patients, providers, and literature review. The validation samples comprised a mail survey cohort (N = 377) and a clinical cohort (N = 56). Both cohorts provides evidence for internal consistency of the derived subscales, test-retest reliability, content validity, concurrent validity, and construct validity. Principal components and Rasch measurement model analyses were applied sequentially to survey sample data, reducing test length to 44 questions, divided into six subscales: mobility, symptoms, emotional well-being (depression), general contentment, thinking/fatigue, and family/social well-being. Fifteen initially rejected questions were added back as miscellaneous (unscored) questions for their potential clinical and empirical value. The mobility subscale was strongly predictive of the Kurtzke Extended Disability Status Scale and the Scripps Neurologic Rating Scales. The other five subscales were not, indicating they measure aspects of patient quality of life not captured by the neurologic exam. The final 59-item English language instrument (FAMS version 2) is available for inclusion in clinical trials and clinical practice.

Glutamate receptor binding in the human hippocampus and adjacent cortex during development and aging

Distinct patterns of age-related alterations in NMDA (MK801 binding) and non-NMDA, AMPA (CNQX), and kainate binding have been identified in human hippocampus and parahippocampal gyrus in normal individuals with no evidence of degenerative brain disease ranging in age from 24 gestational weeks to 94 years. Whereas MK801 binding did not alter substantially over this age range, CNQX binding rose from low levels in the fetus to maximum levels between neonate and middle age, and kainate binding declined extensively from the perinatal to adult stage. Following maturity, there were no significant changes in kainate binding, although MK801 binding increased in CA1 and CA3 and CNQX binding declined in several regions, particularly CA2 and subiculum. For each receptor binding the timing of these fluctuations ocurring during development and aging varied within different regions of the dentate gyrus, hippocampus proper, subicular complex, and entorhinal cortex examined. The transient peaks of receptor binding are likely to reflect processes of synaptogenesis and pruning and may provide clues regarding the role of the different glutamate receptor subtypes in various pathologies of the hippocampus and adjacent cortex associated with developmental disorders (of genetic origin or due to perinatal trauma or insult). The absence of substantial changes in any subtype examined from middle to old age suggests alterations in transmitter binding to these glutamate receptors are not involved in senescent neurodegeneration.

Nurses taking on junior doctors' work: a confusion of accountability

The number of hospital based posts in which nurses take over clinical work previously done by junior doctors is growing. Accountability for the scope of such new roles and the standards of practice which apply to them are still unclear. When analysed together and compared, the regulations arising from the professional bodies (GMC and UKCC), civil law concerning certain wrongs to patients, and employment law are sometimes contradictory and hard to interpret. The resulting uncertainties about appropriate management for clinical roles evolving between the professions, coupled with an increasingly litigious public, put the nurses and consultants involved at risk of complaints and of disciplinary and legal action. Drawing on our current research into changing clinical roles at the medical-nursing interface, we suggest strategies to reduce risk. Doctors and nurses should be equal partners in planning and managing these new posts, patients should be informed adequately about the nature of the postholder's role and training, significant changes in the work of such postholders should be formally acknowledged by the employer and relevant insurers, individuals taking up new roles should have access to legal advice and support to cover legal risk, and national regulatory bodies need to work together to harmonise their codes of practice in relation to changing clinical roles between the professions.

Establishing equivalence between scaled measures of quality of life

In this paper, methodologies which have been used in the pharmaceutical industry to demonstrate the equivalence of drug preparations, are applied to the measurement of quality of life (QOL). This approach is feasible when the generated data are measured on the same scale. Data from the quality of life instruments are transformed into interval scales by means of an appropriate scaling procedure. It is demonstrated that equivalence of QOL instruments is linked by a linear relationship between the QOL instruments Functional Assessment of Cancer Therapy (FACT) and the Functional Living Index-Cancer (FLIC). The linear relationship is derived using orthogonal least squares regression which takes into account that both measures are subject to error.

Beta-amyloidosis in normal aging and transmitter signaling in human temporal lobe

Interactions between abnormal amyloid precursor protein metabolism and cholinergic dysfunction are increasingly apparent. Both of these major features of Alzheimer's disease occur in restricted loci in normal aging--a potential model for early Alzheimer type pathology. Entorhinal cortex is particularly vulnerable to beta-amyloidosis and compared with other cortical areas is remarkable for the relatively high density of nicotinic (3H-nicotine) but not other cholinergic or glutamate receptor binding. With increasing age, post-maturity, there is a persistent decline in nicotinic receptor binding in entorhinal cortex whereas muscarinic M1 and non-M1, glutamate NMDA and non-NMDA receptors are spared. Normal elderly individuals, distinguished by the absence of beta A4 immunoreactive plaques in this area, are differentiated from those with plaques by higher nicotine binding. Amongst individuals with an established history of smoking tobacco, nicotinic receptor binding and hippocampal choline acetyltransferase were elevated compared with non-smokers and preliminary evidence indicates a reduced density of cortical plaques. These findings are consistent with the hypothesis that down regulation of the nicotinic cholinergic receptor--a ligand gated calcium channel known to control the expression of neurotrophins--plays a role in the evolution of Alzheimer-type pathology.

Rates of reinfection with Echinococcus granulosus, Taenia hydatigena, taenia ovis and other cestodes in a rural dog population in Uruguay

A survey was undertaken to determine both the prevalence of, and reinfection rates with Echinococcus granulosus and other cestodes in the Department of Florida, Uruguay. Baseline prevalence was determined in 303 rural dogs which then, in 4 groups, were re-examined 2, 4, 8 or 12 months later. Baseline prevalences for E. granulosus, Taenia hydatigena, Taenia ovis and Dipylidium caninum were 13.2, 13.9, 2.3 and 13.2%, respectively. The frequency distribution of E. granulosus was over-dispersed. Dogs in the population became infected with E. granulosus between 2 and 4 months after treatment (prevalences at 2, 4, 8 and 12 months were 0, 6.8, 18.6 and 27.9%, respectively). There was no indication that there was a predisposition of dogs to infection with the Odds Ratio being 1.0. Dogs were infected with T. hydatigena and D. caninum within 2 months and with T. ovis between 2 and 4 months after treatment. The implications of these different rates of reinfection in the dog population on anthelmintic control strategies against cystic echinococcosis are discussed.

Teething in babies: separating fact from fiction

In one study, out of 50 babies hospitalised for symptoms attributed to teething, 48 had an organic cause of illness. Symptoms may include a slight rise in temperature, disturbed sleep and feeding, irritability, swollen tender gums and dribbling. Diarrhoea, respiratory symptoms, pulling at the ears, fever or convulsions should not be attributed to teething and require medical attention.

Patterns of Cryptosporidium antigen and oocyst excretion in calves studied by reverse passive haemagglutination and light microscopy

A reverse passive haemagglutination (RPH) assay incorporating a monoclonal antibody against Cryptosporidium parvum oocysts was used to follow Cryptosporidium coproantigen excretion by calves. RPH detected soluble antigen that passed 0.22 micron filters. Non-specific reactions that occurred in some samples were markedly reduced by heat treatment of the faecal specimens and were abolished by filtration after heat treatment. Results were compared with oocyst counts performed by microscopy of modified Ziehl-Neelsen (MZN) stained faecal smears. Five hundred and thirty-two daily specimens were examined from 30 calves. The mean age at which positive results for both oocysts and antigen was detected was 9 days (range 5-15 days), and excretion lasted for 5-11 days with some cycling of positive reactions in some calves. The occasional cycling to a negative reaction demonstrates a need to take samples from consecutive days to ensure diagnosis. Two hundred and ninety-one (54.7%) specimens were negative in both tests, 178 (33.5%) were positive in both, 14 (2.6%) were positive only by microscopy, and 49 (9.2%) were positive only by RPH. By these criteria the kappa coefficient of agreement between the tests was good (0.753). Compared with MZN, the sensitivity of RPH is 92.7%, specificity 85.6%, positive predictive value 78.4% and negative predictive value 95.4%. The method is simple, objective, has ease of quality control, and either single samples or batches can be processed.

The independent NDU

This paper looks at the work of the first nursing development unit (NDU) to be developed in the independent sector. The author describes a number of initiatives being developed by nursing staff, including audit, professional development and expanding the role of the nurse practitioner.

Comprehensiveness and bias in reporting clinical trials. Study of reviews of pneumococcal vaccine effectiveness

PURPOSE

To assess the extent to which relevant controlled clinical trials are cited and summarized in review articles, and to determine whether citation of relevant clinical trails is biased as to study results.

DATA SOURCES

Articles were identified by searching MEDLINE and EMBASE databases.

STUDY SELECTION

Review articles published between 1986 and 1988 on the clinical effectiveness of pneumococcal vaccine.

DATA EXTRACTION

Proportion of relevant clinical trials cited and whether citation is biased by study results.

DATA SYNTHESIS

The proportion of relevant primary studies cited per review article ranged from 0% to 36% (mean 9%). The number of trials cited per review ranged from zero to six (mean 1.2). In nine of 17 reviews, no clinical trials were cited. Study populations and outcome(s) were specified and results presented quantitatively for 0 to 27% of relevant trials per review (mean 6%). Unsupportive trials were almost twice as likely to be cited as supportive trials.

CONCLUSIONS

Reporting of the results of relevant clinical trials in reviews of pneumococcal vaccine effectiveness is incomplete. Our findings suggest a need for greater scientific rigour in preparing, reviewing, and editing review articles.

Transmission dynamics of Echinococcus granulosus, Taenia hydatigena and Taenia ovis in sheep in Uruguay

A base-line survey was carried out on the transmission dynamics of Echinococcus granulosus, Taenia hydatigena and Taenia ovis in sheep in the Department of Florida, Uruguay. Mean life expectancy at birth of the sheep population in this Department was estimated at 3.5 and 4.8 years for male and female sheep, respectively. Both intensity and prevalence of E. granulosus infection increased with age providing no evidence that immunity was acquired in the population. This revealed that E. granulosus was only relatively stable and in an equilibrium endemic steady state with an estimate of the basic reproduction ratio (Ro) of about 1.2. The mature larval population in sheep was over-dispersed with parameter k, from fitting a negative binomial, being 0.199 and 0.556 in 42- and 54-month-old sheep, respectively. The mean number of cysts increased by 1.05 cysts per year and the infection pressure was calculated as 0.174 infections per year, implying that each infection consisted of 693.6 eggs to produce 6.03 cysts. Neither intensity nor prevalence of infection with T. hydatigena or T. ovis increased with age. This indicated that immunity was acquired to reinfection by both parasites and they were in an equilibrium hyperenedemic steady state with an estimated Ro of 4.2-5.8. Viability and fertility of E. granulosus, and viability of T. hydatigena cysts in the older age groups were low. The effects of the different transmission levels of the parasites on potential control strategies are discussed.

The Bristol-Myers Anorexia/Cachexia Recovery Instrument (BACRI): a brief assessment of patients' subjective response to treatment for anorexia/cachexia

A brief visual analogue instrument was developed and tested in the context of a multicentre randomized double-blinded four-dose trial of megestrol acetate for the treatment of AIDS-related anorexia/cachexia. This nine-item instrument, the Bristol-Myers Anorexia/Cachexia Recovery Instrument (BACRI), was administered every 4 weeks after initiation of study drug (placebo vs 100 mg, 400 mg or 800 mg of drug). The purpose of the instrument was to quantify patient perception of benefit in areas such as decreased concern over weight, decreased concern over appearance, increased pleasure in eating and increase in global perception of quality of life. Post-trial psychometric evaluation of the instrument strongly supported the use of a seven-item index of subjective recovery from symptoms of anorexia/cachexia (BACRI-7) and a single criterion item depicting patient perception of benefit (BACRI-1). The BACRI-7 and BACRI-1 scales showed significant improvement over 12 weeks in patients who received higher dose active drug (400 and 800 mg) compared with the placebo and 100 mg doses. Further differentiation of 400 vs 800 mg arms was seen in the BACRI-7 results, consistent with dose-response improvements in weight and lean body mass changes. Quadratic trends over time in lean body mass change and provider-rated appetite grade suggested peak therapeutic effect at 8 weeks for these endpoints, whereas the absence of these trends in overall weight and patient-reported BACRI scores suggested that these benefits are more persistent. Although subjective (patient-reported) benefit is strongly associated with objective indicators of improvement, there remains the possibility that there is some added, independent benefit of megestrol acetate to subjective well-being.

Libyostrongylus dentatus n. sp. (Nematoda: Trichostrongylidae) from ostriches in North America, with comments on the genera Libyostrongylus and Paralibyostrongylus

Libyostrongylus dentatus sp. n. is described from ostriches on farms from North Carolina and Texas. Nematodes were recovered from the posterior proventriculus and under the koilon lining of the gizzard; the parasites occurred in mixed infections with Libyostrongylus douglassii. The species is distinguished from congeners by the presence of a prominent, dorsal, esophageal tooth; in males by the structure of the dorsal ray and spicules; and in females by small eggs (52-62 microns in length), a sublateral vulva situated at 93% of the body length from the anterior, and a strongly curled, digitate, tail with cuticular inflations at the anus. Conflicts in the generic diagnoses of Libyostrongylus and Paralibyostrongylus were apparent, based on the structure of the dorsal ray or position of rays 3-5 of the copulatory bursa. These can only be resolved based on phylogenetic analyses of the 11 nominal species referred to these genera.

Expression of E6/E7 or SV40 large T antigen-coding oncogenes in human corneal endothelial cells indicates regulated high-proliferative capacity

PURPOSE

Human corneal endothelial cells are thought to have limited capacity for proliferation. Little is known about the mechanisms that regulate the proliferation of these cells. The authors introduced oncogenes into human corneal endothelial cells to modulate proliferation. In addition, they sought to establish cell lines to facilitate study of human corneal endothelial cells.

METHODS

Early-passage human corneal endothelial cells were transduced with disabled retrovirus (pLXSN16E6/E7) coding for the human papilloma virus type 16 transforming oncoproteins E6 and E7. Early-passage cells were also stably transfected by electroporation with the pMTV-D305 plasmid vector, in which SV40 large T antigen (SV40 LTAg) mRNA expression is positively regulated by the mouse mammary tumor virus promoter. Expression of E6/E7 mRNA or SV40 LTAg mRNA in cell lines was monitored with the polymerase chain reaction. SV40 LTAg protein expression was detected by immunocytology and Western blot analysis.

RESULTS

Human corneal endothelial cells were efficiently infected with disabled retrovirus coding for E6/E7, and seven strains of cells have continued active proliferation for more than 50 population doublings (PD) (< 8 control PD). E6/E7 mRNA was expressed by each cell strain. E6/E7 transformed cells proliferate rapidly and form a monolayer of cells with a high degree of contact inhibition. Transfection with pMTV-D305 is less efficient, and only a single strain was developed. pMTV-D305-transfected endothelial cells (dexamethasone induced) proliferated at a lower rate than E6/E7-transduced cells or cells transfected with a vector (pSV3neo) in which SV40 LTAg is constitutively regulated. In the absence of dexamethasone, the proliferation of pMTV-D305-transfected cells was even slower, but cells continued to produce SV40 LTAg mRNA and protein. The latter results indicated that SV40 LTAg mRNA continued to be synthesized at significant levels in pMTV-D305-transfected cells in the absence of the inducer dexamethasone.

CONCLUSIONS

This study suggests that human corneal endothelial cells have a high capacity for proliferation. Thus, cell division is normally controlled in human corneal endothelial cells by poorly characterized, but efficient, mechanisms. Because the E6 and E7 proteins, as well as the SV40 large T antigen, specifically bind to and interfere with the activity of the retinoblastoma (RB) and p53 tumor suppressor proteins, our results suggest that these proteins have critical roles in regulating the proliferation of human corneal endothelial cells.

Comparison of the binding of nicotinic agonists to receptors from human and rat cerebral cortex and from chick brain (alpha 4 beta 2) transfected into mouse fibroblasts with ion channel activity

(-)-Nicotine, cytisine and carbachol evoked 86Rb efflux from mouse fibroblasts stably transfected with alpha 4 beta 2 chick brain nicotinic subunits. This response to (-)-nicotine was inhibited by mecamylamine and dihydro-beta-erythroidine and was mirrored by a rise in intracellular Ca2+ measured by microspectrofluorimetry. Lobeline and isoarecolone methiodide evoked no significant 86Rb from cells and unlike the above agonists displayed significantly different IC50 values for the displacement of [3H]nicotine from mammalian (rat and human cerebral cortex) and transfected fibroblast membranes.

Lack of effect of lesions in the anterior cingulate cortex and retrosplenial cortex on certain tests of spatial memory in the rat

The effects of cytotoxic lesions in either the anterior cingulate cortex or the retrosplenial cortex were compared with those of fornix lesions on three tests of spatial memory. Two of the tasks, delayed nonmatching-to-position and spatial reversal learning, were tested in an automated apparatus. The third task, forced alternation, was tested in a T-maze. Neither anterior cingulate nor retrosplenial cortex damage produced any significant impairment on the three tasks. In contrast, rats with fornix lesions (hippocampal system damage) were markedly impaired on all three tasks. The results, which were considered in the light of proposals for a hippocampal--anterior thalamic--cingulate system that is important for spatial memory, suggest that neither of the cingulate regions involved in this study form a critical subcomponent of this proposed system. It is therefore assumed that the cingulate cortices are only critical for certain classes of spatial problem. It is also suggested that in some previous studies the effects of inadvertent damage to the cingulum bundle may have contributed to the apparent effects of cingulate lesions.

Burnout, depression, life and job satisfaction among Canadian emergency physicians

Our goal was to determine the level of burnout, depression, life and job satisfaction of Canadian emergency physicians. Six instruments were administered: the emotional exhaustion, depersonalization, and personal accomplishment intensity subscales of the Maslach Burnout Inventory (MBI); the Centre for Epidemiologic Research Self-Report Depression Scale (CES-D); the Satisfaction With Life Scale (SWLS); and the Emergency Physician Job Satisfaction Measurement Instrument (EPJS). Forty-six percent of the sample fell within the medium to high level of emotional exhaustion, 93% within the medium to high range for depersonalization, and 79% within the medium to low range for personal accomplishment. Sixty-one percent were satisfied with their lives, and 75.5% were satisfied with their jobs. Multiple regression analysis showed that increased age, being a department head, and increased weeks of holiday per year were positive contributors to EPJS scores (P < 0.05). Involvement in medical education, increased clinical hours worked per year, and region of residence-Quebec were negative contributors to EPJS scores (P < 0.05). Involvement in medical education is a significant factor among physicians experiencing depressive symptomatology. Time away from clinical practice is important to job satisfaction and emotional well-being.

Toxocara vitulorum: maternal transfer of antibodies from buffalo cows (Bubalis bubalis) to calves and levels of infection with T vitulorum in the calves

The levels of antibody to the excretory/secretory antigens of the infective larvae and adults of Toxocara vitulorum were measured by gel precipitation and ELISAs in the serum and colostrum of 12 buffalo cows naturally infected with T vitulorum and in the serum of their calves. The antibody levels were compared with the extent of T vitulorum infection as judged by faecal egg counts in the calves. The patterns of bands of the larval antigens and gel precipitating antibodies in cow serum taken one month before calving, in cow colostrum and in calf serum were very similar. Nine cows and their calves had gel precipitating antibodies but the remaining three cows and their calves did not. The ELISA detected anti-larval antibodies in the colostrum of all 12 cows and calves. With the exception of one calf there was a strong correlation (r = 0.902) between the antibody titre in cow colostrum and the titre of passively acquired antibody in calf serum. The titres of these passively acquired antibodies declined to their lowest levels in calves 12 to 25 days of age; the antibody concentrations then began to increase up to day 42 and remained stable for the remainder of the experiment (105 days). The titres of antibodies to the antigens of the adult worms, examined in four cows and their calves, were lower than the titres to the larval antigens; the calves absorbed this anti-adult antibody from the colostrum and the antibody levels reached a plateau between days 12 and 30 and remained stable for the rest of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Periparturient reduction in buffalo of mitogen-induced lymphocyte proliferation and antibody to Toxocara vitulorum

Lymphocyte and antibody reactivity were examined during the periparturient period in buffalo cows naturally infected with Toxocara vitulorum. Titres of antibodies to an extract of T. vitulorum larvae increased about 3 months before parturition. Antibody titres declined at about the time of parturition and remained low for up to 3 months into lactation. Lowered titres were found in the IgG class and not the IgM class of immunoglobulins. Levels of lymphocyte transformation induced by the mitogens concanavalin A and pokeweed mitogen declined markedly from one to 2 weeks before until one to 2 weeks after parturition. The relationship between this suppressed immunological reactivity and vertical transmission of T. vitulorum larvae is discussed.

Teaching parents to look after children's teeth

Children's toothpastes with fluoride help to prevent decay, but parents should ask their dentist before giving fluoride supplements to children. Overdosage is harmful. Sugars eaten as part of a meal do less harm to teeth than those eaten frequently as snacks. Sugar-free infant drinks and children's confectionery are now on the market and are more "tooth friendly". Look out for the "happy tooth" symbol. Babies can be registered with NHS dentists as soon as the first teeth start to come through, and should be taken regularly to the dentist throughout childhood. Under the NHS scheme, dentists are paid a capitation fee to provide continuing preventive care and treatment for children free of charge.