Two-way referral bias: evidence from a clinical audit of lymphoma in a teaching hospital

The objective of this study was to evaluate the effect of referral bias in a clinical audit of lymphoma in a university hospital. We compared demographic and clinical characteristics as well as survival for Jerusalem residents (local) and referred (distant) patients diagnosed from 1987 to 1992 and treated in our institution. Referred patients were younger (p < 0.0001), and less likely to be immigrants (p < 0.0001), than local patients. Aggressive non-Hodgkin's lymphomas (NHL) were more common in the referred population (p = 0.015). Survival for Hodgkin's disease was consistently better for local patients, but for patients with NHL the findings were reversed. In this study referred patients differed in their clinical and sociodemographic characteristics but did not consistently exhibit a worse outcome than that of local patients. The unpredictable nature of referral bias may be due to better functional status or resources among referred patients, or to selective referral for procedures such as bone marrow transplantation. While reports on the natural history of disease from tertiary institutions may be biased by referral patterns, the direction of the bias is not uniform.

Inadequacy of qualitative implantable cardioverter defibrillator electrogram analysis to distinguish supraventricular from ventricular tachycardia due to electrogram changes during normally conducted complexes

Stored electrograms (EGMs) recorded from ICD leads are used to evaluate the appropriateness of ICD therapies. Stored EGMs different from sinus have been interpreted as ventricular in origin. We present a patient with an ICD for VT who received multiple shocks for a tachycardia with a stored EGM different than sinus, suggesting VT. An electrophysiological study demonstrated EGMs different than sinus during atrial pacing and induced supraventricular arrhythmias. This case points out the limitations of stored EGMs and suggests complete electrophysiological study with analysis of EGMs during induced arrhythmias should be performed prior to discharge.

Interlaboratory variability in fluorescence in situ hybridization analysis. The NCI Bladder Tumor Marker Network

Reliable interpretation of fluorescence in situ hybridization (FISH) data, especially data that have been generated in more than one laboratory, requires knowledge of the sources of variability inherent in FISH analysis. Possible sources of variation may derive from differences in sample preparation, probes used, intrasample heterogeneity, hybridization protocols, counting criteria within and between scorers, fluorescence microscopes, and filters. This study characterized the relative weight of some of these factors in order to determine the degree to which FISH results are comparable between laboratories. We used a hierarchical partitioned chi 2 analysis to measure sources of variation. We found that replicate counts varied no more than expected based on counting statistics (i.e., multinomial variation). However, with replicate hybridizations done in two separate laboratories, the variability increased significantly. Thus, care must be taken when interpreting FISH data that are derived from more than one institution. Previously agreed upon counting criteria as well as standardized FISH hybridization protocols may decrease this variability.

Human immunodeficiency virus encephalitis in SCID mice

The human immunodeficiency virus (HIV) is neuroinvasive and commonly causes cognitive and motor deficits during the later stages of viral infection. (referred to as HIV dementia). The mechanism(s) for disease revolves around secretory products produced from immune-activated brain macrophages/microglia. Recently, we developed an animal model system for HIV dementia that contains xenografts of HIV-1-infected cells inoculated into brains of mice with severe combined immunodeficiency (SCID). This animal system was used to quantitatively evaluate HIV-induced neuropathology. Xenografts of HIV-1-infected human monocytes (placed into the putamen and cortex of SCID mice) remained viable for 5 weeks. HIV-1 p24 antigen expression in mouse brain was persistent. Progressive inflammatory responses (including astrogliosis and cytokine production), which began at 3 days, peaked at day 12. The range of astrocyte proliferative reactions exceeded the inoculation site by > 1000 microns. Brains with virus-infected monocytes showed a > or = 1.6-fold increase in glial fibrillary acidic protein (staining distribution and intensity) as compared with similarly inoculated brains with uninfected control monocytes. These findings paralleled the accumulation and activation of murine microglia (increased branching of cell processes, formation of microglial nodules, interleukin (IL)-1 beta and IL-6 expression). An inflammatory reaction of human monocytes (as defined by HLA-DR, IL-1 beta, IL-6, and tumor necrosis factor-alpha expression) and neuronal injury (apoptosis) also developed after virus-infected monocyte xenograft placement into mouse brain tissue. These data, taken together, demonstrate that this SCID mouse model of HIV-1 neuropathogenesis can reproduce key aspects of disease (virus-infected macrophages, astrocytosis, microglial activation, and neuronal damage). This model may serve as an important means for therapeutic development directed toward improving mental function in HIV-infected subjects with cognitive and motor dysfunction.

Exposure to missile attacks: the impact of the Persian Gulf War on physical health behaviours and psychological distress in high and low risk areas in Israel

The purpose of this study was to compare residents of an area (Tel-Aviv), which was severely afflicted by SCUD missiles during the Persian Gulf War (high risk region), to residents of a low-risk region (Jerusalem) in terms of: (a) changes in physical health, in use of medical or psychological services, and in health behaviours during the period of the war compared to the preceding month; (b) levels of psychological distress (somatization and anxiety) during the war; (c) characteristics of persons at highest risk for psychological distress. Respondents were randomly chosen and interviewed by telephone (N = 545 in Tel-Aviv, N = 406 in Jerusalem). The respondents in both regions reported significant yet similar deterioration in physical health status, and an increase in detrimental health behaviours during the Gulf War. Tel-Aviv residents had significantly higher levels of psychological distress as compared to residents of Jerusalem: in somatization 18 vs 12% respectively (OR = 2.44, CI = 1.39-4.28), in anxiety 34 vs 26% respectively (OR = 1.62, CI = 1.1-2.42). In addition to place of residence, age, ethnicity, religiosity and self-assessed health were identified as characteristics of persons at greater risk for psychological distress.

The prevalence of obesity and its changes over time in middle-aged and elderly men and women in Jerusalem

OBJECTIVE

To study the prevalence and correlates of overweight and obesity in Jerusalem, and changes over a 15-17 year period.

DESIGN

Two cross-sectional surveys in 1970 and in 1986, among residents aged 50 years and more in a defined neighbourhood.

SUBJECTS

The study samples comprised 1267 individuals in 1970 and 1858 in 1986.

RESULTS

In 1986, 33% of women and 16% of men were obese (BMI > or = 30.0 kg/m2). There was a decreasing trend in the prevalence of obesity with age among women, and in men there was no overall trend but the lowest prevalence was in the 75-84 age-group. Significant relationships with education and region of birth were observed in women only. Prevalence was lowest in the more educated and in women born in Europe and America. Subjects' self-appraisal and their report of physicians' diagnosis of health disorders, revealed a significantly higher prevalence of ill-health among obese people. In 1986 the mean body mass index and the prevalence of obesity were higher than in 1970, in both sexes and in almost all age groups. The prevalence rate of obesity (standardized by sex and age) was 21% in 1970 and 25% in 1986, the difference was statistically significant (p = 0.008). The age standardized prevalence rate in each sex was also higher in 1986 although statistically significant only in men (p = 0.037).

CONCLUSION

A community study in Jerusalem revealed a high prevalence of overweight and obesity in 1986 in this middle-aged and elderly population; and a higher mean body mass index and an increased prevalence of obesity were found in 1986 than in 1970, in both sexes. The increased prevalence of obesity among men could not be explained by changes in the age, education and ethnic composition of the population. Among women, the possibility cannot be excluded that part of the increase in obesity was attributable to changes in the distribution of the population by region of birth.

Observer variation in the interpretation of bone scintigraphy

To assess the reliability of bone scintigraphy, a random sample of 100 bone scans was reviewed twice by each of two physicians. Observer variation in the description and interpretation of bone scintigrams varied by diagnosis. Good to excellent k values were obtained for inter- and intraobserver variation in relation to metastasis or normal scans. For degenerative bone disease, as well as the specific agreement on major pathologies other than metastases, k values were found to be moderate. The agreement on the need for further radiographic studies was poor to moderate. The interpretation of bone metastases or normal scintigrams was found to be more reliable in a research setting than in the usual clinical framework, and the latter requires improvement. The interpretation of bone scintigraphy as consistent with degenerative changes is not reliable. The diagnosis should be evaluated by radiography.

Reutilization of previously hybridized slides for fluorescence in situ hybridization

Application of fluorescence in situ hybridization (FISH) to clinical material is sometimes limited by sample size. In addition, heterogeneity among slides prepared from a single sample may lead to variation in FISH analyses. Reutilization of material for repeated FISH analyses would help to alleviate these problems. We have developed a simple procedure for repeated FISH analyses with directly conjugated probes. Previously hybridized probes are removed by incubation in denaturing solution, and slides can then be rehybridized without residual signals remaining. Several cycles of this procedure allow a full complement of chromosomal loci to be analyzed on the same population of cells. Advantages of this protocol include gaining more cytogenetic information from small samples and eliminating the problem of intratumor variability.

Comparison of cephalometric analysis with ethnicity in obstructive sleep apnea syndrome

Many studies have documented significant craniomandibular abnormalities in obstructive sleep apnea syndrome (OSAS) patients. Recent literature clearly describes the cephalometric abnormalities commonly associated with OSAS. Studies have not evaluated specific cephalometric abnormalities that may contribute to OSAS by various ethnic groups. Data were collected on 48 patients (20 Caucasian, 15 Black and 13 Hispanic) with completed cephalometric analysis and polysomnography. Cephalometric landmarks, angles and measurements [angle measured from sella to nasion to subspinale point (SNA), angle measured from sella to nasion to supramentale point (SNB), difference between SNA and SNB (ANB), perpendicular distance from gonion to gnathion to hyoid (MP-H), distance from posterior nasal spine to tip of soft palate (PNS-P) and posterior airway space (PAS)] commonly used in the evaluation of OSAS patients were recorded. Measurements were normalized by dividing the observed value by the mean value for the ethnic group. Statistically significant differences in normalized SNA and SNB appeared in the Black and Hispanic groups when compared to the Caucasian group. For both SNA and SNB, Blacks averaged approximately 3.5% above their ethnic mean, whereas Hispanics averaged 1.8-2.8% below their ethnic mean. There was a statistically significant correlation between respiratory distress index (RDI) and MP-H. These baseline cephalometric differences in the ethnic groups studied suggest that surgical intervention might be approached differently in various ethnic groups. Further studies that evaluate the surgical success achieved by various procedures among different ethnic groups may help define surgical protocol in various ethnic groups for OSAS.

Trends in blood pressure levels over time in middle-aged and elderly Jerusalem residents

Change in blood pressure levels over time was investigated in Jerusalem, in two cross-sectional surveys in 1970 and in 1986 among residents of a neighbourhood aged 50 years and more. The study population comprised 1397 individuals in 1970 and 1858 in the 1986. Age-adjusted mean systolic and diastolic blood pressure levels were lower in 1986 than in 1970 by 6.9 mmHg and 4.7 mmHg, respectively. The prevalence of blood pressure levels above 160 and/or 95 mmHg in 1986 was lower by 50% and there was a twofold increase in current treatment for hypertension. The reduction in blood pressure in both sexes remained evident upon control for confounding effects of age, ethnic group, education, body mass index and reported treatment for hypertension. The proportion of people who had blood pressure levels below 140/90 and did not report being under treatment, increased. The possibility of methodological problems inherent in this type of study were considered. More effective antihypertensive treatment in 1986 can explain only part of the reduction. The decrease in levels of blood pressure as revealed by this study may reflect a real reduction in the population that could explain part of the striking decline in cardiovascular mortality in Israel.

A peer review programme to audit the management of hypertensive patients in family practices in Israel

We introduced and evaluated a self-audit and peer review programme for the management of hypertension in eight urban and rural family medicine practices in northern Israel between January 1991 and December 1992. Changes in the level of blood pressure control and the effect of peer review and self-audit on physicians' management of hypertension were evaluated. Participating physicians were provided with feedback throughout the course of the study. Six hundred and seventy-four hypertensive patients from a total adult population of 4445 patients (15%) were identified in eight practices and followed for two years. The percentage of uncontrolled hypertensives (blood pressure > or = to 160/95 mmHg) decreased from 46.8% at the beginning of the sstudy to 34.3% at its conclusion (P = 0.01). Data on prevalence of hypertension were analysed by participating clinics (prevalence range 8.5-24.6%) and by type of community (rural or urban). In rural communities 50% of the hypertensives were > or = to 70 years of age, compared with 39.5% in the urban practices. Differences in prescribing practices among participating physicians were discussed during peer review group meetings and changes in prescribed medications for hypertension were evaluated. We conclude that this method of self-audit and peer review is effective in improving the management of patients with hypertension in family medicine practices. It was implemented at a minimal cost, is feasible in busy practices and can be generalized to the management of other chronic diseases in the community.

Recent changes in the etiology of hearing disorders: perinatal drug exposure

In recent years, we have observed causes of congenital or early onset hearing disorders that had not been recognized or known to exist before. These include drugs passed to an as-yet unborn child. Principal among them is alcohol, but others, such as cocaine, are now also occupying our attention. This article reviews the effects of such exposure on the communication skills of children who had been exposed. It is not yet clear whether there are specifically auditory effects, nor is it clear whether the communicative effects are long lasting.

Professional evacuation of persons injured in road accidents in Israel is fast but underused

In a study of the evacuation process of injured people from motor vehicle accidents, 2,206 injured evacuees were interviewed in five emergency rooms in Israel. Of these, only 53% were evacuated professionally (by ambulance or helicopter), and only 75% arrived directly to an emergency room. In a logistic regression analysis, differences were found in relation to regions, type of road (urban vs. interurban), education, and severity of the injury. Higher education was associated with lower percentage of professional evacuation. Of those injured who arrived directly at emergency rooms, 67% did so within an hour (the "golden hour"). We found that professional evacuation was more rapid than nonprofessional evacuation.

Iraqi missile attacks on Israel. The association of mortality with a life-threatening stressor

OBJECTIVE

The imminent deadline for the 1991 Persian Gulf War and, subsequently, the 18 missile attacks by Iraq on Israel represented an unusual, short-term, life-threatening stressor for an entire nation. We studied mortality in Israel in January and February 1991 to determine whether excess deaths were precipitated on days of missile attacks.

DESIGN

A time-series mortality study.

SETTING

The state of Israel.

PARTICIPANTS

All Israelis aged 25 years and older.

MAIN OUTCOME MEASURE

Daily mortality by sex, age, region, underlying cause, and place of death.

RESULTS

On January 18, 1991, the day of the first strike on Israeli cities, a 58% increment in total mortality occurred in the Israeli population (95% confidence interval [CI], 34% to 86%; P < .0001), a 77% excess (95% CI, 40% to 120%) in women and a 41% excess (95% CI, 10% to 79%) in men. This excess mortality occurred largely in the targeted Tel Aviv-central coastal plain and Haifa regions from cardiovascular causes and mainly out of hospital, significantly more so (P < .01) in women than men. Subsequently, on 16 attack days no overall excess was noted, yet a 10% increase in out-of-hospital deaths occurred.

CONCLUSIONS

Likely explanations for the initial increase in mortality include acute emotional stress coupled with breathing difficulties induced by gas masks and extended stay in sealed rooms with resultant hypoxia in susceptible individuals. Women were more vulnerable than men. The absence of elevated total mortality in the subsequent attacks suggests a rapid adaptation to the circumstances surrounding the war. The policy of an unventilated sealed room may have been detrimental.

Psychosocial and medical factors in pregnancy outcomes: a case study of Israeli women

Building on a body of research which confirms that psychosocial factors have an important influence on health in general and on pregnancy outcomes in particular, we carried out a prospective study of pregnant women in Israel. We hypothesized that medical pregnancy and delivery outcomes are mediated by psychosocial coping resources and risks. Resources were defined as social ties, and risks as life events self-reported as stressful. The population studied included 233 women who responded to questionnaires after the second trimester of pregnancy. Medical data on the delivery were collected from hospital archives. The questionnaire measured biomedical risks, including general medical and obstetrical history, as well as health behaviours, social ties, and perceived stress. Pregnancy outcomes were classified according to medical measures of abnormalities in mother and child at birth. Our findings show that resources such as the variety of social ties (family, friends, neighbours and colleagues) interacted significantly with biomedical risk. It was found that low scores for social ties anticipated 3.6 times higher negative medical outcome in otherwise healthy women than in those with higher scores for social ties. The findings of the study are discussed in terms of their implications for relating to social competence as a determining element in health and health behaviour.

The relationship between phospholipid content and Ca2+-ATPase activity in the sarcoplasmic reticulum

The relationship between the phospholipid composition of sarcoplasmic reticulum and the activity of the Ca2+, Mg2+-stimulated ATPase was analyzed by digestion of membrane phospholipids with phospholipase C and A2 enzymes of diverse specificity and by detergent extraction. Phospholipase C of Clostridium perfringens and Clostridium welchii, that hydrolyze preferentially phosphatidylcholine (PC), inhibited the Ca2+-ATPase activity parallel with the depletion of phosphatidylcholine from the membrane. Phospholipase C of Bacillus cereus hydrolyzed in addition to PC, phosphatidylethanolamine (PE) and phosphatidylserine (PS), causing complete inhibition of Ca2+-stimulated ATPase activity. Digestion of sarcoplasmic reticulum with the phospholipase A2 of snake or bee venom produced similar effects. The phosphatidylinositol (PI)-specific phospholipases of B. cereus and Bacillus thuringiensis caused less than 10% inhibition of the Ca2+-ATPase, accompanied by the hydrolysis of more than 70% of the phosphatidylinositol content of the membrane, without significant change in PC, PE and PS content. The inhibition of ATPase activity by the C type phospholipases was nearly completely reversed by octaethyleneglycol dodecyl ether (C12E8). These experiments suggest that the full phospholipid content of native sarcoplasmic reticulum (congruent to 100 mol phospholipid per mol Ca2+-ATPase), is required for ATPase activity and there is no indication that PE, PS, and PI play a specific role in ATP hydrolysis. Extraction of sarcoplasmic reticulum phospholipids by detergents such as deoxycholate, cholate and C12E8 also caused proportional inhibition of ATPase activity with the decrease in phospholipid content; the parallel extraction of PC, PE and PI left the phospholipid composition largely unchanged during delipidation. These observations do not support the requirement for a 'lipid annulus' of congruent to 30 phospholipid molecules/Ca2+-ATPase as proposed by Hesketh et al. ((1976) Biochemistry 15, 4145-4151) or the specific interaction of phosphatidylethanolamine with the ATPase molecule proposed by Bick et al. ((1991) Arch. Biochem. Biophys. 286, 346-352).

Pathogenesis of pediatric human immunodeficiency virus type 1 infection

This discussion of the pathogenesis of infant human immunodeficiency virus (HIV) type 1 infection emphasizes features unique to pediatric disease and provides general insights into HIV illness in all populations. Therapies designed to interrupt transmission of HIV can be most efficiently addressed through studies of maternal-infant transmission. The rapid progression of disease in children constantly emphasizes the urgent need for continued progress in treatment of HIV infection and presents a unique opportunity optimally to assess effects of early intervention.

Radiofrequency catheter ablation as a cure for idiopathic tachycardia of both left and right ventricular origin

OBJECTIVES

The purpose of this study was 1) to investigate the efficacy and safety of radiofrequency energy catheter ablation as curative treatment for idiopathic tachycardia of both left and right ventricular origin, and 2) to compare the usefulness of different methods used to map the site of origin of idiopathic ventricular tachycardia.

BACKGROUND

Percutaneous radiofrequency catheter ablation has been used with dramatic success in the treatment of patients with Wolff-Parkinson-White syndrome, atrioventricular node reentrant tachycardia and bundle branch reentrant tachycardia. Limited data are available on the use of radiofrequency energy catheter ablation as curative treatment for idiopathic tachycardia of both left and right ventricular origin.

METHODS

Twenty-eight consecutive patients (13 to 71 years old) presenting with idiopathic ventricular tachycardia were enrolled in the study. The site of origin of both left and right ventricular tachycardia was mapped using earliest endocardial activation times during tachycardia and by pace mapping. These mapping techniques were compared.

RESULTS

Radiofrequency ablation was successful in all eight patients (100%) with left ventricular tachycardia. Tachycardia recurred in one patient. The ablation procedure was complicated by mild aortic insufficiency in one patient. Right ventricular outflow tract tachycardia was successfully ablated in 17 (85%) of 20 patients. The success rate at follow-up was 85%. In one patient, the ablation procedure was complicated by acute ventricular perforation and death. Pace maps from successful ablation sites were better than pace maps from unsuccessful sites (p < 0.004). Endocardial activation times at successful ablation sites were not different from unsuccessful sites (p < 0.13).

CONCLUSIONS

Radiofrequency catheter ablation is an effective treatment for idiopathic ventricular tachycardia. The site of origin of tachycardia is best identified using pace mapping. Significant complications can occur and should be considered in the risk/benefit analysis for each patient.

The yield of bone scintigraphy in cancer and non-cancer patients: its association with indication and clarity of the referral question

The yield of bone scintigraphy was assessed in a general hospital. A random 1:2 sample of the bone studies performed within a year was evaluated. The referral forms were judged to show absent, ambiguous or clear diagnostic questions. The indications for which the study was ordered were matched with the scintigraphic diagnosis, and yield was defined as the proportion of studies with relevant findings on scintigraphy. The overall yield was 23.5%. In cancer patients the yield was 27.2% and in repeat studies 40.2%. In non-cancer patients the yield was 19.8% and when scintigraphy was performed for the evaluation of specific disease entities it was 35.7%. Relatively low-yield indications in non-cancer patients were suspected metastases 11.1%, and evaluation of X-ray abnormalities 11.5%. An association between the clarity of the diagnostic question and the scintigraphic yield was detected in non-cancer patients. When a diagnostic question was absent the yield was 12%, ambiguous 19%, and when it was clear 26%. This correlation is probably attributed to better understanding of this common procedure, and better definition of the diagnostic question in patients with diverse clinical conditions as compared to cancer patients in whom the question always relates to the presence of bone metastases.