On the epidemiology of 'mysterious' phenomena

In the field of epidemiology, research topics are favored or dismissed depending on whether respective variables under investigation are believed to exist according to current scientific theories. Unconventional independent variables or exposures, such as religiousness and spirituality, and controversial dependent variables or outcomes, such as chronic fatigue syndrome, may be considered unacceptable topics for researchers because they do not fit comfortably into the consensus clinical perspectives of mainstream medical scientists or physicians. Disapproval of research in these and other taboo areas is generally masked by claims that such studies are "pseudoscientific," despite hundreds or thousands of peer-reviewed publications on these topics. In reality, seemingly "mysterious" variables are equally as amenable to epidemiologic research as any other exposure or disease. Similarly, alternative therapies are able to be investigated using existing methods, despite claims to the contrary. Such research is vital for scientific understanding to be expanded into new areas of inquiry.

Prevalence and patterns of Gulf War illness in Kansas veterans: association of symptoms with characteristics of person, place, and time of military service

Gulf War veterans have reported health problems that they attribute to their military service, but little is understood about the nature or extent of these conditions. To determine whether Kansas Gulf War veterans are affected by excess health problems, a population-based survey of 1,548 veterans who served in the Persian Gulf War (PGW) and 482 veterans who served elsewhere (non-PGW) was conducted in 1998. Gulf War illness, defined as having chronic symptoms in three of six domains, occurred in 34% of PGW veterans, 12% of non-PGW veterans who reported receiving vaccines during the war, and 4% of non-PGW veterans who did not receive vaccines. The prevalence of Gulf War illness was lowest among PGW veterans who served on board ship (21%) and highest among those who were in Iraq and/or Kuwait (42%). Among PGW veterans who served away from battlefield areas, Gulf War illness was least prevalent among those who departed the region prior to the war (9%) and most prevalent among those who departed in June or July of 1991 (41%). Observed patterns suggest that excess morbidity among Gulf War veterans is associated with characteristics of their wartime service, and that vaccines used during the war may be a contributing factor.

A heterogeneous outbreak of Enterobacter cloacae and Serratia marcescens infections in a surgical intensive care unit

OBJECTIVE

To investigate an outbreak of invasive disease due to Enterobacter cloacae and Serratia marcescens in a surgical intensive care unit (ICU).

DESIGN

Pulsed-field gel electrophoresis (PFGE) analysis of restriction fragments was used to characterize the outbreak isolate genotypes. A retrospective cohort study of surgical ICU patients was conducted to identify risk factors associated with invasive disease. Unit staffing data were analyzed to compare staffing levels during the outbreak to those prior to and following the outbreak.

SETTING

An urban hospital in San Francisco, California.

PATIENTS

During the outbreak period, December 1997 through January 1998, there were 52 patients with a minimum ICU stay of > or = 72 hours. Of these, 10 patients fit our case definition of recovery of E. cloacae or S. marcescens from a sterile site.

RESULTS

PFGE analysis revealed a highly heterogeneous population of isolates. Bivariate analysis of patient-related risk factors revealed duration of central lines, respiratory colonization, being a burn patient, and the use of gentamicin or nafcillin to be significantly associated with invasive disease. Both respiratory colonization and duration of central lines remained statistically significant in a multivariate analysis. Staffing data suggested a temporal correlation between understaffing and the outbreak period.

CONCLUSIONS

Molecular epidemiological techniques provided a rapid means of ruling out a point source or significant cross-contamination as modes of transmission. In this setting, patient-related risk factors, such as respiratory colonization and duration of central lines, may provide a focus for heightened surveillance, infection control measures, and empirical therapy during outbreaks caused by common nosocomial pathogens. In addition, understaffing of nurses may have played a role in this outbreak, highlighting the importance of monitoring staffing levels.

Cefotetan-induced hemolysis associated with antibiotic prophylaxis for cesarean delivery

We describe 3 cases of antibiotic-induced hemolysis associated with cefotetan prophylaxis during cesarean delivery. Each of the 3 patients showed development of significant anemia with documented cefotetan-induced hemolysis. When postpartum anemia is associated with antibiotic use, immune hemolytic anemia should be considered and included in the differential diagnosis.

Rural and remote oral health, problems and models for improvement: a Western Australian perspective

Oral healthcare in rural communities shares many of the dilemmas faced by medicine in providing services to large geographical areas with dispersed populations. This study examined the population data and service provision data relevant to the geographical distribution of oral health care in Western Australia (WA). Of the 1.7 million people resident in WA, 72% were resident in the five major urban centres with only 13% in rural and remote regions. Of the 320 postcode regions, 186 had a population of less than 2500, 31 had a population from 2500 to 5000, 42 from 5000 to 10,000, 37 from 10,000 to 20,000, and 24 had a population greater that 20,000. Almost 80% of postcode regions with a population less than 2500 are in non-urban regions. Of the total of 690 dentists who were analysed in this study, it was found that the vast majority (greater than 85%) worked in practices in postcode regions within metropolitan Perth or the major urban centres. A total of 43 postcode regions did not have a dental practice within their bounds. In order to address this disparity in service availability, strategies including the development of training for medical practitioners and auxiliaries, the use of modern technology, school-based programs and the development of interdisciplinary links should be implemented. These strategies would also facilitate the development of closer links between medical and dental practitioners and the development of skills within the medical fraternity that would facilitate improved oral health in rural and remote communities.

Prenatal sonographic diagnosis of hypochondroplasia in a high-risk fetus

Hypochondroplasia (HCH) is caused by mutations in the fibroblast growth factor receptor type 3 (FGFR 3). Prenatal diagnosis of HCH based exclusively on the sonographic measurements of the fetal skeleton is difficult and has not been reported. We describe a newborn infant with HCH who was born to a mother with achondroplasia (ACH) and a father with HCH. Serial sonographic measurements were recorded from 16 weeks of gestation. All measurements remained normal up to 22 weeks of gestation. At 25 weeks of gestation, the long bones began to appear shorter than expected for gestational age, while the head measurements (biparietal diameter and head circumference) remained normal. The measurements were sufficiently different to distinguish from findings in normal and achondroplastic fetuses. Our findings suggest that it is possible to distinguish the normal fetus from a fetus affected with HCH and to distinguish HCH and ACH from each other based on the sonographic measurements alone. To our knowledge, this is the first report of longitudinal sonographic measurements of HCH in the second and third trimesters.

Undetected vancomycin-resistant Enterococcus in surgical intensive care unit patients

The rates of vancomycin-resistant Enterococcus (VRE) in a high-risk population were investigated prospectively using an active surveillance method. The costs of conducting active surveillance were calculated. Among the 10 patients found to have VRE, routine cultures identified 3 (30%); thus, 70% of the VRE-colonized patients would have gone undetected in the absence of active surveillance. The total cost for 5 weeks of active surveillance was $2,234. Although active surveillance identified a high rate of VRE-colonized patients who otherwise may not have been identified, it remains to be determined if the additional costs are justified and result in reduced transmission.

The epidemiology of chronic fatigue in San Francisco

Despite considerable research on chronic fatigue syndrome (CFS) and conditions associated with unexplained chronic fatigue (CF), little is known about their prevalence and demographic distribution in the population. The present study describes the epidemiology and characteristics of self-reported CF and related conditions in a diverse urban community. The study used a cross-sectional telephone screening survey of households in San Francisco, followed by interviews with fatigued and nonfatigued residents. Respondents who appeared to meet case definition criteria for CFS, based on self-reported fatigue characteristics, symptoms, and medical history, were classified as CFS-like cases. Subjects who reported idiopathic chronic fatigue (ICF) that did not meet CFS criteria were classified as ICF-like cases. Screening interviews were completed for 8,004 households, providing fatigue and demographic information for 16,970 residents. Unexplained CF was extremely rare among household residents <18 years of age, but was reported by 2% of adult respondents. A total of 33 adults (0.2% of the study population) were classified as CFS-like cases and 259 (1.8%) as ICF-like cases. Neither condition clustered within households. CFS- and ICF-like illnesses were most prevalent among women and persons with annual household incomes below $40,000, and least prevalent among Asians. The prevalence of CFS-like illness was elevated among African Americans, Native Americans, and persons engaged in clerical occupations. Although CFS-like cases were more severely ill than those with ICF-like illness, a similar symptom pattern was observed in both groups. In conclusion, conditions associated with unexplained CF occur in all sociodemographic groups but appear to be most prevalent among women, persons with lower income, and some racial minorities.

Solubilization of subtilisin in CO2 using fluoroether-functional amphiphiles

Carbon dioxide is a naturally abundant, environmentally benign solvent whose use, like water, in a process is not regulated by either EPA or FDA. Unfortunately, polar compounds such as amino acids and proteins are essentially insoluble in carbon dioxide. Further, alkyl-functional surfactants, which have been shown to allow extraction of proteins into conventional organic solvents, exhibit very poor or negligible solubility in CO2 at pressures below 50 MPa. Consequently, highly CO2-soluble fluoroether-functional surfactants have been generated and used to solubilize subtilisin Carlsberg from aqueous buffer and cell culture medium into CO2, with recovery accomplished by depressurization. Both the amount of protein solubilized in the emulsion and the extent of activity retention by the protein following recovery are functions of the initial protein concentration in the buffer. This, plus the observation that the presence of protein affects the stability of the emulsion, suggests that some of the protein is sacrificed to act as a stabilizer in these systems. In addition to solubilization via an inverse emulsion, it has also been shown that one can strip protein-surfactant aggregates from a middle phase emulsion using pure CO2, suggesting an ion-pairing type mechanism.

Emerging infectious diseases: can we meet the challenge?

Demonstration of quality health care includes documentation of outcomes of care. Surveillance is a comprehensive method of measuring outcomes and related processes of care, analyzing the data, and providing information to members of the health care team to assist in improving those outcomes. Surveillance is an essential component of effective clinical programs designed to reduce the frequency of adverse events such as infection or injury.

Recommended practices for surveillance. Association for Professionals in Infection Control and Epidemiology, Inc. Surveillance Initiative working Group

Demonstration of quality health care includes documentation of outcomes of care. Surveillance is a comprehensive method of measuring outcomes and related processes of care, analyzing the data, and providing information to members of the health care team to assist in improving those outcomes. Surveillance is an essential component of effective clinical programs designed to reduce the frequency of adverse events such as infection or injury. Although there is no single or "right" method of surveillance design or implementation, sound epidemiologic principles must form the foundation of effective systems and must be understood by key participants in the surveillance program and supported by senior management. Teamwork and collaboration across the health care spectrum are important for the development of surveillance plans. Each health care organization must tailor its surveillance systems to maximize resources by focusing on population characteristics, outcome priorities, and organizational objectives. To ensure quality of surveillance, the following elements must be incorporated: A written plan should serve as the foundation of any surveillance program. The plan should outline important objectives and elements of the surveillance process so that resources can be targeted appropriately. Thoroughness or intensity of surveillance for an area of interest must be maintained at the same level over time. Fluctuations of a surveillance rate have no meaning unless the same level of data collection is maintained. External rate comparisons are meaningless unless the systems used have comparable intensity. All the elements of surveillance should be used with consistency over time. This includes application of surveillance definitions and rate calculation methods. Personnel resources need to be appropriate for the type of surveillance being performed. This includes trained professionals who understand epidemiology and who have access to continuing professional education opportunities. Other resources essential to surveillance include computer support, information and technology services, clerical services, and administrative understanding and support to maintain a quality program. As a means of quality control and to ensure accuracy, the data and process of surveillance should undergo periodic evaluation and validation. This document is intended to assist professionals who plan and conduct surveillance programs as well as those who assure that there is appropriate organizational support to accomplish appropriate surveillance. While design of surveillance systems must be unique for each organization, incorporation of these seven core Recommended Practices for Surveillance provides a scientific framework to approach surveillance programs.

Response to radiation therapy and prognosis in breast cancer patients with BRCA1 and BRCA2 mutations

BACKGROUND AND PURPOSE

The purpose of this study is to evaluate overall survival in BRCA1 or BRCA2 breast cancer patients, describe presenting stage, review histologic findings and evaluate response to radiotherapy.

MATERIALS AND METHODS

A retrospective study was performed evaluating breast cancer patients with known mutations of BRCA1 or BRCA2. Patients from 12 different pedigrees were cross-referenced with the Utah Cancer Registry (UCR), histologic findings were verified and radiotherapy records were reviewed for acute response to treatment. Actuarial survival calculations were performed and patients were matched for age, date of diagnosis and tumor size.

RESULTS

Thirty breast cancer patients with BRCA1 mutations were found to have 34 breast cancers (four had bilateral metachronous lesions) and 20 breast cancer patients with BRCA2 mutations were found to have 22 breast cancers (two had bilateral metachronous disease). The median age at diagnosis was 49 years (range 21-77 years) and 42 years (range 23-83 years), respectively, for BRCA1 and BRCA2 patients. Unusual histologic types of breast cancers were represented with 7% (4/56) medullary and 5% (3/56) lobular carcinomas. Complete staging was possible for 63% (35/56) of cancers. Stages I, II, III and IV represented 26, 63, 6 and 6% of cancers, respectively. The most severe radiation reaction was moist desquamation which was self-limiting and developed in 29% (6/21) of irradiated patients. The mean follow-up was 9.8 and 7.5 years for BRCA1 and BRCA2 cancers, respectively. Kaplan-Meier survival analysis demonstrated 5-year survival values of 75% for BRCA1 patients, 73% for BRCA2 patients, 70% for matched controls and 69% for UCR controls. No statistically significant differences were evident between the groups at 5 or 10 years.

CONCLUSIONS

Despite their younger age at presentation, breast cancer patients harboring BRCAI or BRCA2 mutations present at a similar stage, display a normal acute reaction to radiotherapy and have a similar prognosis when compared with sporadic breast cancer patients.

Quantitative methods in research on complementary and alternative medicine. A methodological manifesto. NIH Office of Alternative Medicine

OBJECTIVES

This article summarizes the deliberations of the Quantitative Methods Working Group convened by the National Institutes of Health (NIH) in support of the NIH Office of Alternative Medicine.

METHODS

The working group was charged with identifying methods of study design and data analysis that can be applied to empirical research on complementary and alternative medicine. This charge was broad and inclusive and addressed the evaluation of alternative therapies, the investigation of the basic science of complementary medical systems, studies of health promotion and disease prevention, and health services research.

RESULTS

The working group produced a "methodological manifesto," a summary list of seven recommended methodological guidelines for research on alternative medicine. These recommendations emphasize the robustness of existing research methods and analytic procedures despite the substantive unconventionality of alternative medicine.

CONCLUSIONS

Contrary to the assertions of many researchers and alternative practitioners, established methodologies (eg, experimental trials, observational epidemiology, social survey research) and data-analytic procedures (eg, analysis of variance, logistic regression, multivariate modeling techniques) are quite satisfactory for addressing the majority of study questions related to alternative medicine, from clinical research on therapeutic efficacy to basic science research on mechanisms of pathogenesis and recovery.

BRCA1 sequence analysis in women at high risk for susceptibility mutations. Risk factor analysis and implications for genetic testing

CONTEXT

A mutation in the BRCA1 gene may confer substantial risk for breast and/or ovarian cancer. However, knowledge regarding all possible mutations and the relationship between risk factors and mutations is incomplete.

OBJECTIVES

To identify BRCA1 mutations and to determine factors that best predict presence of a deleterious BRCA1 mutation in patients with breast and/or ovarian cancer.

DESIGN

A complete sequence analysis of the BRCA1 coding sequence and flanking intronic regions was performed in 798 women in a collaborative effort involving institutions from the United States, Italy, Germany, Finland, and Switzerland.

PARTICIPANTS

Institutions selected 798 persons representing families (1 person for each family) thought to be at elevated a priori risk of BRCA1 mutation due to potential risk factors, such as multiple cases of breast cancer, early age of breast cancer diagnosis, and cases of ovarian cancer. No participant was from a family in which genetic markers showed linkage to the BRCA1 locus.

MAJOR OUTCOME MEASURES

Sequence variants detected in this sample are presented along with analyses designed to determine predictive characteristics of those testing positive for BRCA1 mutations.

RESULTS

In 102 women (12.8%), clearly deleterious mutations were detected. Fifty new genetic alterations were found including 24 deleterious mutations, 24 variants of unknown significance, and 2 rare polymorphisms. In a subset of 71 Ashkenazi Jewish women, only 2 distinct deleterious mutations were found: 185delAG in 17 cases and 5382insC in 7 cases. A bias in prior reports for mutations in exon 11 was revealed. Characteristics of a patient's specific diagnosis (unilateral or bilateral breast cancer, with or without ovarian cancer), early age at diagnosis, Ashkenazi Jewish ethnicity, and family history of cancer were positively associated with the probability of her carrying a deleterious BRCA1 mutation.

CONCLUSIONS

Using logistic regression analysis, we provide a method for evaluating the probability of a woman's carrying a deleterious BRCA1 mutation for a wide range of cases, which can be an important tool for clinicians as they incorporate genetic susceptibility testing into their medical practice.

Cancer risks in two large breast cancer families linked to BRCA2 on chromosome 13q12-13

The penetrance of the BRCA2 gene on chromosome 13q12-13 has been estimated in two large, systematically ascertained, linked families, by use of a maximum-likelihood method to incorporate both cancer-incidence data and 13q marker typings in the families. The cumulative risk of breast cancer in female gene carriers was estimated to be 59.8% by age 50 years (95% confidence interval [95% CI] 25.9%-78.5%) and 79.5% by age 70 years (95% CI 28.9%-97.5%). The cumulative risk of breast cancer in male carriers was estimated to be 6.3% (95% CI 1.4%-25.6%) by age 70 years. There was no evidence of any risk difference between the two families. These results indicate that the lifetime breast cancer risk in BRCA2 carriers, for at least a subset of mutations, is comparable to that for BRCA1. A significant excess of ovarian cancer in gene carriers was observed (relative risk 17.69, based on three cases), but the absolute risk of ovarian cancer was less than that reported for BRCA1. Significant excesses of laryngeal cancer (relative risk 7.67, based on two possible carriers) and prostate cancer (relative risk 2.89, based on five possible carriers) were also observed. One case of ocular melanoma, as well as a second eye cancer of unspecified histology, occurred in obligate gene carriers.

A prospective study of insulin sensitivity and glucose metabolism in women using a continuous subdermal levonorgestrel implant system

OBJECTIVE

Decreased insulin sensitivity and deterioration in oral glucose tolerance curves have been reported with oral contraceptive use, particularly with those containing levonorgestrel. However, the subdermal levonorgestrel systems release a lower dosage of steroid and avoid the first pass through the liver that occurs with oral administration. We hypothesized, therefore, that continuous subdermal levonorgestrel has no significant effect on insulin sensitivity and other indices of glucose metabolism.

METHODS

Nine women desiring a subdermal hormonal contraceptive system were recruited for this longitudinal prospective study. Each subject underwent a 3-hour frequently sampled intravenous glucose tolerance test immediately before insertion and after 6 months of continuous use. Insulin sensitivity and glucose effectiveness were determined using a mathematical minimal modeling approach. Glucose clearance and fasting and peak levels of glucose and insulin were examined as well. The matched-pair data were analyzed using paired t tests.

RESULTS

There was no significant change in insulin sensitivity, glucose effectiveness, glucose clearance, or fasting or peak insulin levels. Fasting glucose levels remained within a normal range.

CONCLUSIONS

Subdermal levonorgestrel appears to have no significant effect on tissue insulin sensitivity or glucose metabolism after 6 months of continuous use.

Surveillance for chronic fatigue syndrome--four U.S. cities, September 1989 through August 1993

PROBLEM/CONDITION

Although chronic fatigue syndrome (CFS) has been recognized as a cause of morbidity in the United States, the etiology of CFS is unknown. In addition, information is incomplete concerning the clinical spectrum and prevalence of CFS in the United States.

REPORTING PERIOD COVERED

This report summarizes CFS surveillance data collected in four U.S. cities from September 1989 through August 1993.

DESCRIPTION OF SYSTEM

A physician-based surveillance system for CFS was established in four U.S. metropolitan areas: Atlanta, Georgia; Wichita, Kansas; Grand Rapids, Michigan; and Reno, Nevada. The objectives of this surveillance system were to collect descriptive epidemiologic information from patients who had unexplained chronic fatigue, estimate the prevalence and incidence of CFS in defined populations, and describe the clinical course of CFS. Patients aged > or = 18 years who had had unexplained, debilitating fatigue or chronic unwellness for at least 6 months were referred by their physicians to a designated health professional(s) in their area. Those patients who participated in the surveillance system a) were interviewed by the health professional(s); b) completed a self-administered questionnaire that included their demographic information, medical history, and responses to the Beck Depression Inventory, the Diagnostic Interview Schedule, and the Sickness Impact Profile; c) submitted blood and urine samples for laboratory testing; and d) agreed to a review of their medical records. On the basis of this information, patients were assigned to one of four groups: those whose illnesses met the criteria of the 1988 CFS case definition (Group I); those whose fatigue or symptoms did not meet the criteria for CFS (Group II); those who had had an identifiable psychological disorder before onset of fatigue (Group III); and those who had evidence of other medical conditions that could have caused fatigue (Group IV). Patients assigned to Group III were further evaluated to determine the group to which they would have been assigned had psychological illness not been present, the epidemiologic characteristics of the illness and the frequency of symptoms among patients were evaluated, and the prevalence and incidence of CFS were estimated for each of the areas.

RESULTS

Of the 648 patients referred to the CFS surveillance system, 565 (87%) agreed to participate. Of these, 130 (23%) were assigned to Group I; 99 (18%), Group II; 235 (42%), Group III; and 101 (18%), Group IV. Of the 130 CFS patients, 125 (96%) were white and 111 (85%) were women. The mean age of CFS patients at the onset of illness was 30 years, and the mean duration of illness at the time of the interview was 6.7 years. Most (96%) CFS patients had completed high school, and 38% had graduated from college. The median annual household income/for CFS patients was $40,000. In the four cities, the age-, sex-, and race-adjusted prevalences of CFS for the 4-year surveillance period ranged from 4.0 to 8.7 per 100,000 population. The age-adjusted 4-year prevalences of CFS among white women ranged from 8.8 to 19.5 per 100,000 population.

INTERPRETATION

The results of this surveillance system were similar to those in previously published reports of CFS. Additional studies should be directed toward determining whether the data collected in this surveillance system were subject to selection bias (e.g., education and income levels might have influenced usage of the health-care system, and the populations of these four surveillance sites might not be representative of the U.S. population).

ACTIONS TAKEN

In February 1997, CDC began a large-scale, cross-sectional study at one surveillance site (Wichita) to describe more completely the magnitude and epidemiology of unexplained chronic fatigue and CFS.

Fatiguing illness among employees in three large state office buildings, California, 1993: was there an outbreak?

The objective was to determine if a cluster of chronic fatigue syndrome (CFS)-like illness had occurred among employees in two large state office buildings in northern California, and to identify risk factors for and features of fatiguing illness in this population.

DESIGN

case-control study.

POPULATION AND SETTING

Over 3300 current employees in two state office buildings and employees in a comparable "control" building. Information was collected on demographic and occupational variables, the occurrence of fatiguing illness for at least one month in the previous year, and the presence of 36 symptoms. A total of 3312 (82%) of 4035 employees returned questionnaires. Overall, 618 (18.7%) persons reported fatigue lasting at least one month; including 382 (11.5%) with fatigue of at least six months' duration and 75 (2.3%) with symptoms compatible with a CFS-like illness. Independent risk factors for fatigue lasting one month or longer were found to be Native American ethnicity (OR 2.4, CI 1.1,5.3), Hispanic ethnicity (OR 1.7, CI 1.3,2.3), female sex (OR 1.5, CI 1.2,1.9), gross household incomes of less than $50,000 (OR 1.3, CI 1.1,1.6), and less than a college education (OR 1.3, CI 1.1,1.6). Similar risks were observed for persons who reported fatigue lasting six months or longer. Female sex (OR 3.2, CI 1.7, 6.4) was the only independent risk factor found for those persons classified as having a CFS-like illness. Case prevalence rates for all three categories of fatigue, as determined by multivariate analysis, were not significantly different among buildings. Despite finding a substantial number of employees with fatiguing illness in the two state office buildings, the prevalence was not significantly different than that for a comparable control building. Previously unidentified risk factors for fatigue of at least one month and at least six months identified in this population included Hispanic ethnicity, not having completed college, and income below $50,000.

Immune responses associated with chronic fatigue syndrome: a case-control study

An exploratory case-control study was conducted to assess whether the many reported differences in the immune function of chronic fatigue syndrome (CFS) patients are detectable in rigorously defined cases of CFS. Although many studies have reported differences between cases and controls in various measures of immune function, none of these differences were found in all studies. In this study, no differences were found in white blood cell numbers; immune complex, complement, or serum immunoglobulin levels; delayed type hypersensitivity and allergic responses; NK cell function; and proliferative responses to mitogens and antigens. Marginal differences were detected in cytokine responses and in cell surface markers in the total CFS population. However, when the patients were subgrouped by type of disease onset (gradual or sudden) or by how well they were feeling on the day of testing, more pronounced differences were seen.

M-mode echocardiographic evaluation of fetal and infant hearts: longitudinal follow-up study from intrauterine life to year one

OBJECTIVE

Our purpose was to evaluate cardiac variables, including right and left end-diastolic and end-systolic dimensions by use of M-mode echocardiography during fetal, neonatal (transitional), and infancy periods to understand hemodynamic adaptation during these periods.

STUDY DESIGN

Fifty-three fetuses were enrolled in this study. Echocardiography evaluations were started as early as the sixteenth week of gestation and were repeated every 4 to 6 weeks until term, on postnatal days 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastolic and end-systolic measurements were made according to published standards. Mean and SEM for each of the end-diastolic and end-systolic measurements were calculated for each of 11 study periods. Data were analyzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t tests were used for significance.

RESULTS

Left ventricular end-diastolic and end-systolic correlated positively with advancing age (R2 = 0.93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R2 = = 0.361, p < 0.05), and right ventricular end-diastolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.0001). Heart rate significantly decreased with advancing age (p < 0.001), whereas ejection fraction for either the right or the left ventricle did not change significantly with advancing age.

CONCLUSION

This suggests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions without having to increase contractility reserve.

The identification of DL-threo dihydrosphingosine and sphingosine as novel inhibitors of extracellular signal-regulated kinase signalling in airway smooth muscle

We present entirely novel evidence that DL-threo dihydrosphingosine and sphingosine are inhibitors of the extracellular signal-regulated kinase (ERK) signalling cassette in mammalian cells. We show that DL-threo dihydrosphingosine is effective against both growth factor- and G-protein-dependent activation of ERK. We conclude that DL-threo dihydrosphingosine may represent an important pharmacological cell-permeable agent that may be usefully employed to block smooth muscle cell proliferation.

Sphingomyelin-derived lipids differentially regulate the extracellular signal-regulated kinase 2 (ERK-2) and c-Jun N-terminal kinase (JNK) signal cascades in airway smooth muscle

In ASM cells platelet-derived growth factor stimulates rapid transient sphingosine phosphate formation, the activation of extracellular signal-regulated kinase 2 (ERK-2), the phosphorylation of p70(56K), and a ninefold increase in DNA synthesis. In contrast, this growth factor fails to activate c-Jun N-terminal kinase (JNK). Based upon these findings, we have tested whether the sphingomyelin-derived sphingolipids play a role in growth factor signalling by assessing their effect on ERK-2, JNK, and p70(56K). We demonstrate that sphingosine phosphate induces the activation of ERK-2, is ineffective against JNK, and fails to induce the phosphorylation of p70(56K). The latter may explain why it is a poor mitogen when added directly to ASM cells. In contrast, sphingosine and cell-permeable ceramides elicit the prominent tyrosyl phosphorylation and activation of JNK, are poor stimulators of ERK-2, and do not induce the phosphorylation of p70(56K). Therefore, the specificity of signalling through either ERK-2 or JNK cascades may be determined by the rapid agonist-dependent interconversion of these sphingomyelin-derived lipids. This may also provide a dynamic mechanism that enables growth factors and cytokines to elicit pleiotropic cell responses, such as proliferation and cell survival. For instance, both ceramide and sphingosine will elicit growth arrest via activation of JNK, whereas sphingosine phosphate will potentiate growth-factor-stimulated DNA synthesis, a consequence of the activation of ERK-2, Furthermore, under certain conditions, sphingosine and ceramide stimulate cAMP formation, a negative modulator of cell growth, whereas sphingosine phosphate depresses cAMP, thereby enhancing its own growth-promoting properties. From these studies, it is evident that sphingosine phosphate displays a signalling profile that is consistent with it mediating part of the action of platelet-derived growth factor.

The complete BRCA2 gene and mutations in chromosome 13q-linked kindreds

Breast carcinoma is the most common malignancy among women in developed countries. Because family history remains the strongest single predictor of breast cancer risk, attention has focused on the role of highly penetrant, dominantly inherited genes in cancer-prone kindreds (1). BRCA1 was localized to chromosome 17 through analysis of a set of high-risk kindreds (2), and then identified four years later by a positional cloning strategy (3). BRCA2 was mapped to chromosomal 13q at about the same time (4). Just fifteen months later, Wooster et al. (5) reported a partial BRCA2 sequence and six mutations predicted to cause truncation of the BRCA2 protein. While these findings provide strong evidence that the identified gene corresponds to BRCA2, only two thirds of the coding sequence and 8 out of 27 exons were isolated and screened; consequently, several questions remained unanswered regarding the nature of BRCA2 and the frequency of mutations in 13q-linked families. We have now determined the complete coding sequence and exonic structure of BRCA2 (GenBank accession #U43746), and examined its pattern of expression. Here, we provide sequences for a set of PCR primers sufficient to screen the entire coding sequence of BRCA2 using genomic DNA. We also report a mutational analysis of BRCA2 in families selected on the basis of linkage analysis and/or the presence of one or more cases of male breast cancer. Together with the specific mutations described previously, our data provide preliminary insight into the BRCA2 mutation profile.

Seroepidemiology of chronic fatigue syndrome: a case-control study

We performed serological testing for a large number of infectious agents in 26 patients from Atlanta who had chronic fatigue syndrome (CFS) and in 50 controls matched by age, race, and sex. We did not find any agent associated with CFS. In addition, we did not find elevated levels of antibody to any of a wide range of agents examined. In particular, we did not find elevated titers of antibody to any herpesvirus, nor did we find evidence of enteroviral exposure in this group of patients.

Home health care for cancer patients: insights from the American Indian community

With the confounding effects of an aging population, as well as advances in the treatment of cancers, the cure rates and associated recovery time for patients have increased. In the past, recovery from cancer treatment was often associated with extended hospital stays. However, shorter lengths of stay and the use of home health care is now the accepted standard of care. For the recovering patients, and their families, sensitivity to their cultural needs may often be overlooked given the diverse nature and background of home health care providers. Within the Indian Health Service, the cultural needs of the patients are taken into account. Through this paper we hope to provide a description of this unique program of home health care for American Indians who live on or near reservations and trust lands and Alaskan Natives who live in traditional villages.

Chromatographic investigation of the glycosylation pattern of alpha-1-acid glycoprotein secreted by the HepG2 cell line; a putative model for inflammation?

In certain pathophysiological conditions, such as rheumatoid arthritis, there are alterations in the glycosylation pattern of the acute phase protein, alpha-1-acid glycoprotein (AGP). These changes are likely to be functionally significant, however, verification of the latter role requires a system which reflects in vivo glycosylation changes in AGP and also produces sufficient quantities of the protein for further study. The human hepatoma cell line HepG2 is documented as displaying a shift in the glycosylation pattern of glycoproteins from normal state to acute phase after stimulation with inflammatory mediators. We have isolated AGP from the culture medium of HepG2 cells both before and after stimulation with a cytokine preparation and analysed the glycosylation pattern of each preparation, after enzymatic release, by high pH anion-exchange chromatography. Before stimulation, the glycosylated population was similar to a profile of AGP isolated from normal plasma; however, cytokine stimulation resulted in a shift to a profile which was consistent with that of AGP from a rheumatoid arthritis sufferer. Thus a HepG2 cell culture system is capable of being a crude model of the changes in glycosylation of acute phase proteins although it has a tendency to produce oligosaccharide chains which are not fully sialylated.

Prevalence of cardiovascular disease risk factors in a southwestern Native American tribe

A cross-sectional study was conducted among the Pascua Yaqui Indian tribe in Tucson, AZ, in 1990 to document the prevalence of cardiovascular disease risk factors. Cardiovascular disease is the leading cause of mortality for Native Americans and for members of the Pascua Yaqui tribe specifically. A total of 230 randomly selected adults, ages 25-65 years, who were listed as members on the tribal roll, participated, resulting in a 73-percent participation rate for those contacted. The five risk factors studied included diabetes, hypertension, hypercholesterolemia, obesity, and smoking. Only 14 percent of participants had none of the risk factors; 52 percent had two or more factors. Obesity was the most prevalent, being present in 69 percent of the women and 40 percent of the men, followed by diabetes, 35 percent of men and 39 percent of women. Twenty-six percent of the population had hypertension, and 43 percent of men were smokers, compared with 24 percent of women. Hypercholesterolemia was present in 19 percent of men and 14 percent of women. The rates of diabetes, obesity, hypertension, and smoking documented in this tribe are relatively high and can serve as a baseline for evaluating future prevention efforts.

Mammography and Pap smear screening of Yaqui Indian women

The Pascua-Yaqui Tribe of Arizona receives its health care services at a local neighborhood health center in Tucson and a satellite clinic located on the reservation. Using a computerized data base from the health center, the authors determined the use rates by Pascua-Yaqui women ages 35-65 of the Papanicolaou smear and mammography screening. Among active users of the health center, 31-36 percent had received a Papanicolaou smear, according to the yearly data bases examined from 1986 to 1990, while 65 percent of the women had received at least one smear test over the entire 5-year period. Regarding mammography screening, 41-43 percent of the women ages 50-65 had received a mammogram in the years studied, and 51-58 percent of the women ages 40-49 had been screened. In all, 67 percent had received at least one mammogram during the 1988-90 period when the center offered mammography. This population of 35-65-year-old American Indian women, for whom financial access is not a barrier, were receiving Papanicolaou smears and mammograms at rates comparable with other segments of the U.S. population but at lower rates than those recommended by the American Cancer Society and National Cancer Institute. The challenge for the health center is to reach those women who are eligible for services but do not use them and to address the nonfinancial barriers to care such as language, transportation, and gender-specific issues.

Specific labeling of Candida tropicalis peroxisomal proteins with photoreactive fatty-acid derivatives

The labeling of Candida tropicalis peroxisomal proteins with photoreactive fatty-acid derivatives was investigated. Proteins having molecular masses of 70 kDa, 48 kDa and 15 kDa were labeled with 11-m-diazirinophenoxy-[11-3H]undecanoate while 11-m-diazirinophenoxy-[11-3H]undecanoyl-CoA labeled proteins of 70 kDa and 55 kDa. The 70 kDa protein labeled with both photoreactive probes was resolved into two bands by electrophoresis on a gradient polyacrylamide gel; immunoprecipitation with anti-fatty acyl-CoA oxidase showed that these proteins are fatty-acyl-CoA oxidases. In purified peroxisomal membranes, two proteins of 36 kDa and 25 kDa were labeled with the photoreactive fatty-acid probe, whereas very little labeling of the above proteins or other proteins was observed with the fatty-acyl-CoA probe. The photoaffinity labeling method described is, thus, clearly capable of identifying and distinguishing between proteins having an affinity for fatty acid or fatty-acyl-CoA. The labeling also identified a fatty-acid-binding site on the 16 kDa peroxisomal matrix protein as well as on two peroxisomal acyl-CoA oxidases. This approach thus provides a general means for the identification of fatty-acid metabolizing enzymes, as well as for the identification of fatty-acid-binding sites on known enzymes.

Identification of phospholipase D (PLD) activity in mouse peritoneal macrophages

It is now believed that PLD may contribute to the sustained generation of diacylglycerol (DAG) within activated cells. DAG can be formed from phosphatidylcholine by the sequential actions of PLD and phosphatidic acid phosphohydrolase. Phorbal myristate acetate (PMA, 1 microM), A23187 (10 microM) or platelet-activating factor (PAF, 100 nM) caused significant enhancement of intracellular 14C-phosphatidic acid levels 2-5 min after the addition of stimulus, in cultures of peritoneal macrophages pre-labelled with 14C-palmitate. Bacterial lipopolysaccharide (LPS) (5 micrograms/ml) or zymosan (375 micrograms/ml) also stimulated the production of 14C-phosphatidic acid, but over a longer time course (15-60 min). In the presence of 1% ethanol each stimulus caused significant production of 4C-phosphatidylethanol at the expense of 14C-phosphatidic acid, thus confirming a contribution of PLD in these reactions. This is the first report of PLD activity in this cell type.