Risk of death from Alzheimer's disease in a community population of older persons

A random sample of 467 persons over age 65 years from the population of an urban US community, stratified by age, sex, and performance on a brief memory test, underwent clinical evaluation for dementing illness in 1982-1984. Of these persons, 134 had probable Alzheimer's disease, 166 had possible Alzheimer's disease, and 167 had no evidence of Alzheimer's disease. Over a median follow-up period of 4.9 years following evaluation, 165 (35%) died. Overall, persons with probable Alzheimer's disease had a relative risk of death 1.44 (95% confidence interval (Cl) 1.05-1.96) times that of the unaffected. Level of cognitive impairment and the presence of cachexia upon physical examination both strongly and independently modified risk of death. Among those with probable Alzheimer's disease, mortality for those with mild or moderate cognitive impairment and no evidence of cachexia was comparable to that of the unaffected. However, among those with probable Alzheimer's disease and either severe cognitive impairment or cachexia, the risk of death was substantially higher. Persons with probable Alzheimer's disease who had both severe cognitive impairment and clear cachexia had a risk of death 4.60 (95% Cl 1.63-13.1) times that of unaffected persons.

Studies on the leishmaniases in the Sudan. 3. Clinical and parasitological studies on visceral and mucosal leishmaniasis

The epidemiological, clinical and laboratory findings of 27 patients with visceral leishmaniasis (VL) and six with mucosal leishmaniasis (ML) in Sudan are described. The diagnosis was confirmed by the demonstration of amastigotes in bone-marrow in 20 cases with VL (80%) and impression smears in 2 cases with ML. The enzyme-linked immunosorbent assay and direct agglutination test were positive in all the sera tested. The leishmanin test was positive in all patients with ML, the diameter of the reaction ranging from 18 to 28 mm (mean 23 mm). Only one isolate (from a patient with VL) grew sufficiently well in culture to be typed and this was characterized by isoenzyme electrophoresis as Leishmania donovani zymodeme LON-46. The possibility that the ML isolate could have been L. major zymodeme LON-1 is discussed. The importance of further research to isolate and identify by biochemical procedures a more representative range of isolates of Leishmania from different clinical types in the Sudan, in order to elucidate questions such as the relationship between the vectors and possible animal reservoirs, is emphasized.

Studies on the leishmaniases in the Sudan. 2. Clinical and parasitological studies on cutaneous leishmaniasis

In the Omdurman Hospital for Tropical Diseases, Sudan, from 6 October to 1 December 1986, 736 patients with cutaneous leishmaniasis (CL) were studied. The duration of the lesions varied from a few days to 4 months, usually (56%) 1-3 months. Multiple lesions ranging from one to 50 (mean = 4) were present in 80% of cases. Ulcerative lesions were found in 44%, nodulo-ulcerative in 31%, nodular in 31% and others, including infiltrated, fungating and warty lesions, in 5% of patients. The lower limbs were involved in 66%, upper limbs in 50%, face in 6%, back in 4%, chest in 2%, abdomen in 1% and buttocks in 0.1%. Lesions were also found on the ear, scalp, genitalia and mucocutaneous junctions. Lymphatic involvement was present in 11% of the patients, secondary infection in 18%, fever in 17%, pain in 38% and itching in 61%; 3% of the patients were diabetics. Features of diffuse cutaneous leishmaniasis were noted in one patient and three cases presented with an 'id' reaction. A slit-skin smear was positive in 88% of the cases. Using thin-layer starch gel electrophoresis, 23 stocks from man and one from Arvicanthis niloticus were identified by the characterization of 12 enzymes as Leishmania major zymodeme LON-1. Various therapeutic regimens are discussed. Only patients with severe lesions (approximately 15%) were given 3 to 4 weeks' treatment with intravenous Pentostam, to which all except 2 responded satisfactorily with minimal side effects.

Evidence of genetic recombination in Leishmania

In the genus Leishmania there has been no convincing demonstration of genetic exchange, and it has been proposed that reproduction is clonal. However, preliminary characterization of two strains of Leishmania isolated from wild animals in a zoonotic focus of cutaneous leishmaniasis in the Eastern Province of Saudi Arabia, has suggested that they may represent hybrids of Leishmania major and Leishmania arabica. Evidence presented here strongly supports this hypothesis. Isoenzyme analysis and molecular karyotyping of cloned organisms indicated that the putative hybrids are distinct from other species of Leishmania, and possess characteristics of both L. major and L. arabica. Experiments using highly specific probes demonstrated that kinetoplast minicircle DNA from the putative hybrid contained L. major-specific, but not L. arabica-specific sequences. DNA fingerprinting data obtained using 6 genomic DNA probes were consistent in all cases with a L. major/L. arabica recombinant genotype, and implied both diploidy and allelic segregation. These observations suggest that sexual reproduction may generate genetic diversity within natural Leishmania populations.

Use of multiple visits to increase blood pressure tracking correlations in childhood

Previous studies of childhood blood pressure have shown tracking correlations, which estimate the magnitude of association between initial and subsequent measurements, to be lower than corresponding adult values. Inasmuch as this disparity could arise from failing to account for a larger week-to-week variability in children, blood pressure was measured for 4 successive years, on four weekly visits in each year, and with three measurements at each visit, using a random-zero sphygmomanometer, in a cohort of 333 schoolchildren aged 8 through 15 at entry. Ninety percent of subjects had measurements in 1 or more years of follow-up. For all follow-up periods (1, 2, and 3 years from baseline), the Pearson correlation coefficient (r) for both systolic and diastolic blood pressure rose substantially with the number of weekly visits used to calculate each subject's yearly blood pressure (P less than .0001). For systolic pressure, the 3-year r values for 1, 2, 3, and 4 visits were .45, .55, .64, and .69, respectively. For diastolic pressure (Korotkoff phase 4), the corresponding values were .28, .41, .47, and .54. These higher multiple-visit estimates of tracking approximate published adult values and raise the possibility that prediction of adult blood pressure from childhood measurements may be improved by averaging readings from multiple weekly visits.

Peak expiratory flow rate and 5-year mortality in an elderly population

During a population survey in 1982-1983 among all community-dwelling elderly aged 65 years and over in East Boston, Massachusetts, measurements of peak expiratory flow rate using the mini-Wright peak flow meter were made on 3,582 participants (80% of those eligible). The average peak flow rate was 315 liters/minute, and a measure of peak flow rate adjusted for age, sex, height, and weight was computed. This was a highly significant (p less than 0.0001) predictor of 5-year total mortality, whose ascertainment was virtually complete. The relative risk was 1.27 (95 percent confidence interval 1.19-1.36) per 100 liters/minute decrease in peak flow rate, using a proportional hazards model including terms for age, sex, and smoking. There was no apparent modification of the effect of this measure in various categories of smoking, with relative risks of 1.24 for nonsmokers, 1.29 for ex-smokers, and 1.26 for current smokers. This finding also persisted after adjustments for other covariates, including respiratory symptoms such as cough, phlegm, and wheeze; cardiovascular risk factors such as history of myocardial infarction and stroke; and systolic and diastolic blood pressures; socioeconomic status; scores on simple tests of cognitive function; measures of physical activity and functional ability; and self-assessed state of health. In a stepwise model including all of these variables, the relative risk was 1.16 (p less than 0.0001) per 100 liters/minute decrease in peak flow rate, indicating that peak flow rate is a strong independent predictor of total mortality in the elderly.

Use of brief cognitive tests to identify individuals in the community with clinically diagnosed Alzheimer's disease

Two brief screening tests, the Short Portable Mental Status Questionnaire (SPMSQ) and the East Boston Memory Test (EBMT), were included in a population questionnaire administered to 3,811 persons 65 years of age and older. A detailed clinical evaluation was then administered to 467 persons (drawn from high, medium and low performers on the EBMT) to determine who was cognitively impaired and the disorders that were responsible for that cognitive impairment. The results showed that the EBMT was better at enriching the population of the poor performance group with persons who had Alzheimer's disease (AD). It had a lower refusal rate among non-proxy respondents: 2% for the EMBT versus 9% for the SPMSQ. The sensitivity and positive predictive value were also higher for the EBMT than the SPMSQ when the diagnosis of interest was AD. However, there were persons with AD in all strata of performance on both the EBMT and the SPMSQ, emphasizing the importance of selecting persons from all performance strata in multistage community studies of AD.

Splenectomy attenuates the inappropriate diuresis associated with tumor necrosis factor administration

Tumor necrosis factor (TNF) is an important mediator of the systemic response to gram-negative sepsis and endotoxemia. We studied the renal effects of a sublethal TNF infusion in dogs (0.54 = 10(5) international units per kilogram of body weight during a six hour period). The TNF-infused dogs (n = 4) had marked polyuria and natriuresis in comparison with those in the control group (n = 12) (urine output, 35.3 +/- 4.1 versus 3.7 +/- 0.5 millimeters per kilogram per six hours p less than 0.01; sodium excretion, 2.82 +/- 0.27 versus 0.75 +/- 0.19, p less than 0.01). To evaluate the role of the spleen in this response, seven dogs that had splenectomy were infused with TNF. Splenectomy abolished both the polyuria and the natriuresis; this could not be explained by the differences in fluid balance or in hemodynamic or metabolic alterations. Treatment with ibuprofen given intravenously (12.5 milligrams per kilogram 40 minutes before and three hours after the beginning of TNF infusion) in eight dogs that did not undergo splenectomy also abolished these renal effects. Prostaglandin 2 (PGE2) concentrations in selected blood samples from the splenic vein did not increase with TNF infusion, excluding circulating PGE2 as a possible mediator of the renal effects. The results of these studies indicate that, during septic challenge or severe inflammation, the spleen participates in signaling the kidney to increase water and sodium excretion. These renal events are mediated through the cyclo-oxygenase pathway.

The acetylator phenotypes of Saudi Arabians with coronary arterial atheroma

The acetylator phenotypes were determined by means of a sulfamethazine test in 101 Saudi Arabian patients with authenticated coronary atheroma; 65 were found to be slow acetylators. This distribution of phenotypes is not significantly different from that in 220 controls, 148 of whom were slow acetylators. This finding makes it unlikely that compounds containing a primary aromatic amino or a hydrazino group are involved in the aetiology or pathogenesis of coronary atheroma.

Epidemiology of delirium: an overview of research issues and findings

This paper provides a review of research issues and findings on the epidemiology of delirium. Despite the fact that research on this important geriatric syndrome has been conducted for many decades, several methodological issues make it difficult to compare findings across studies. In this paper we first discuss broadly methodological issues related to diagnosis, case-finding, and populations studied. We next review data on the occurrence and consequences of the syndrome. A discussion of the design and preliminary results of the Commonwealth-Harvard Study of Delirium in Elderly Hospitalized Patients documents both how we responded to the methodological issues outlined and how these choices influenced our findings. We conclude with a discussion of the needs for further research on the epidemiology of delirium.

Latent Semantic Indexing of medical diagnoses using UMLS semantic structures

The relational files within the UMLS Metathesaurus contain rich semantic associations to main concepts. We invoked the technique of Latent Semantic Indexing to generate information matrices based on these relationships and created "semantic vectors" using singular value decomposition. Evaluations were made on the complete set and subsets of Metathesaurus main concepts with the semantic type "Disease or Syndrome." Real number matrices were created with main concepts, lexical variants, synonyms, and associated expressions. Ancestors, children, siblings, and related terms were added to alternative matrices, preserving the hierarchical direction of the relation as the imaginary component of a complex number. Preliminary evaluation suggests that this technique is robust. A major advantage is the exploitation of semantic features which derive from a statistical decomposition of UMLS structures, possibly reducing dependence on the tedious construction of semantic frames by humans.

A new species of Leishmania isolated from the great gerbil Rhombomys opimus

Leishmania turanica n.sp., found infecting the desert rodent Rhombomys opimus in the southern territories of the USSR and the Mongolian People's Republic, is described. This parasite exists sympatrically with L. major and L. gerbilli in R. opimus and is the predominant species. A total of 284 isolates of L. turanica from R. opimus, 3 from naturally infected Phlebotomus andrejevi and 1 from P. papatasi were characterized and found to be clearly distinguishable on isoenzyme and nuclear DNA characteristics from all other Old World taxa of Leishmania.

Visceral leishmaniasis in HIV infection and AIDS: clinical features and response to therapy

The development of visceral leishmaniasis with atypical features in an AIDS patient, and the recent flurry of reports of visceral leishmaniasis in HIV-infected individuals prompted the review of its manifestations in the 47 reported cases. Splenomegaly, which is almost always a feature of visceral leishmaniasis in the immunocompetent host, was absent in eight. Antibodies to Leishmania donovani, which are present in approximately 95 per cent of immunocompetent patients with visceral leishmaniasis, were absent in 29 of 45 (66 per cent) of HIV-infected patients tested. Nine HIV-positive patients with visceral leishmaniasis did not exhibit a primary clinical response to therapy with antimonials and of those who did show a response, relapse occurred in 13, at a mean 4.5 months after stopping therapy. Seventeen patients are known to have died often in association with respiratory disease; Leishmania was seen in one bronchial lavage specimen and in lung tissue in one post-mortem performed. In order to improve the prognosis of visceral leishmaniasis in HIV-infected patients diagnosis will have to be made earlier, taking account of the atypical features, and treatment will need to be improved, both initially and perhaps also by the use of long-term maintenance therapy.

Short-term variability of measures of physical function in older people

Self reported physical function was assessed in telephone interviews approximately 3 weeks apart for a sample of 193 persons aged 69 or older. Three measures of physical function were used: a modified Activities of Daily Living scale, three items proposed by Rosow and Breslau, and five items from among those used by Nagi. Agreement between first and second interviews was very good; most subjects reported no impairment in function at either interview. Among those who reported some impairment, the degree of limitation within the specific activities reported as limited and the total number of activities with any degree of limitation agreed exactly for most and within one level for almost all subjects. There was no evidence to suggest that age or cognitive impairment affected the variability of the responses, and reported declines and improvements in function were about equally common.

Leishmania infecting man and wild animals in Saudi Arabia. 8. The influence of prior infection with Leishmania arabica on challenge with L. major in man

A clinical trial is described of an attempt to protect against Leishmania major by prior vaccination with live L. arabica. After a single, previously leishmanin-negative, adult male volunteer was bitten by 8 Phlebotomus papatasi infected with L. arabica, no infected lesions were observed. He remained leishmanin-negative and his lymphocytes reacted weakly to antigens of L. arabica or L. major. Subsequently he and 3 other leishmanin-negative adult male volunteers were vaccinated with cultures containing 4 x 10(6) promastigotes of L. arabica. All remained leishmanin-negative but their lymphocytes showed some response to both L. arabica and L. major antigens. 96 d after vaccination these 4, and another, non-vaccinated, volunteer were challenged with 2 x 10(6) promastigotes of L. major. Active cutaneous, ulcerated lesions developed in all 5 volunteers. The lesions in 3 vaccinated volunteers were associated with marked lymphadenitis and beading, but the lesions started to heal spontaneously within 120-250 d after challenge. The lesion in the fourth vaccinated volunteer was less severe and lymphadenitis was not observed. The lesion in the unvaccinated subject developed more slowly and was smaller, but more chronic, than those in the vaccinated individuals. Marked cross-reactivity in terms of lymphocyte proliferation and interferon-gamma production was observed between L. major and L. arabica in both directions in subjects exposed first to one or the other organism. Although the procedure followed in this trial failed to give protection against L. major, further studies in volunteers should be considered.

Biochemical characterization of Leishmania (Viannia) braziliensis and Leishmania (Viannia) peruviana by isoenzyme electrophoresis

Leishmanial organisms isolated from 24 patients with Andean cutaneous leishmaniasis (uta) and from 7 with sylvatic leishmaniasis in both cutaneous and mucosal forms were characterized on the basis of their isoenzyme profiles for 13 enzymes using both cellulose acetate (CA) and thin-layer starch gel (TLS) electrophoretic techniques. Malate dehydrogenase (MDH) after electrophoresis on CA or TLS and mannose phosphate isomerase (MPI) on TLS were the only enzymes of 13 examined which discriminated between the organisms from patients with uta (L. (V.) peruviana) and those with sylvatic leishmaniasis (L. (V.) braziliensis). Mannose phosphate isomerase gave more clear-cut and reproducible discrimination than did MDH on either TLS or CA, and it is suggested that MPI is a reliable enzyme marker that can be used in routine TLS electrophoresis to distinguish between L. (V.) peruviana and L. (V). braziliensis.

Reasoning strategies and the use of biomedical knowledge by medical students

This paper reports one of a series of studies conducted to investigate the role of biomedical knowledge in clinical reasoning. It was motivated by findings from our earlier studies that demonstrate that when specific basic science information is provided to medical students prior to solving a clinical case, they are unable to use this information in explaining the patient problem. An experiment was designed to investigate the use of biomedical information in the explanation of a clinical problem without any basic science information (spontaneous explanation) and where basic science information was provided after the clinical case (biomedically primed explanation). The results are discussed in the context of a two-stage model of diagnostic reasoning. The first stage is referred to as data-driven reasoning, and is characterized by the triggering of inferences from observations in the data to hypotheses. The second stage is designated as predictive reasoning, and is characterized by the generation of inferences driven by hypotheses. The results show that, with the exception of final-year medical students, the use of biomedical information interfered with the data-driven reasoning process. However, it did facilitate the process of predictive reasoning by the students. It is proposed that a sound disease classification scheme is necessary before biomedical knowledge can facilitate both data-driven and predictive reasoning during clinical problem-solving.

Primary adenocarcinoma of the appendix

Thirteen cases of primary appendicular adenocarcinoma are reported. This rare tumour usually presents as acute appendicitis. The correct diagnosis is rarely entertained before or during surgery. The main treatment choice lies between appendicectomy alone and appendicectomy followed by right hemicolectomy. There are anatomical reasons for advising the latter and survival figures from the literature tend to support this preference. The cases reported here indicate that in the period 1972-1984, in the North West Region, there was a slight preference for appendicectomy alone. The additional procedure of right hemicolectomy did not confer any clear-cut survival advantage.

Demonstration of prosthetic activation of central auditory pathways using [14C]-2-deoxyglucose

The cochlear prosthesis is not applicable to patients who lack an implantable cochlea or an intact vestibulocochlear nerve. Direct electrical stimulation of the cochlear nucleus (CN) of the brain stem might provide a method for auditory rehabilitation of these patients. A penetrating CN electrode has been developed and tissue tolerance to this device demonstrated. This study was undertaken to evaluate metabolic activation of central nervous system (CNS) auditory tracts produced by such implants. Regional cerebral glucose use resulting from CN stimulation was estimated in a series of chronically implanted guinea pigs with the use of [14C]-2-deoxyglucose (2-DG). Enhanced 2-DG uptake was observed in structures of the auditory tract. The activation of central auditory structures achieved with CN stimulation was similar to that produced by acoustic stimulation and by electrical stimulation of the modiolar portion of the auditory nerve in control groups. An interesting banding pattern was observed in the inferior colliculus following CN stimulation, as previously described with acoustic stimulation. This study demonstrates that functional metabolic activation of central auditory pathways can be achieved with a penetrating CNS auditory prosthesis.

Parenteral nutrition. Pharmaceutical problems of compatibility and stability

A typical All-in-One (AIO) parenteral nutrition mixture in a 3-litre polymeric infusion bag will consist of lipid emulsion, amino acids, glucose, electrolytes, trace elements and vitamins. This varied mixture of chemical entities provides the potential for a number of chemical and physicochemical interactions that can compromise the clinical safety and efficacy of the product. The destabilisation of the lipid emulsion in the presence of electrolytes is a major problem. Although a predictive equation for the maximum concentrations of mono-, di- and trivalent ions causing instability has been proposed, it is too simplistic to be of significant value. The reasons for this are discussed as well as the stability implications of other additives to the parenteral nutrition mixture.