Issues in human immunodeficiency virus (HIV) screening programs. Unlike test sensitivity and specificity, the false positive and negative predictive values (probabilities of mislabeling an individual being tested) depend heavily on the prevalence of the infection of the human immunodeficiency virus (HIV) as well as the quality of the kit. A consequence of this dependence is that the false positive predictive value can reach a high magnitude such as 0.9; that is, 90% of the positive tests are false. This raises many important issues pertaining to the current practice of HIV screening such as to how to control these misclassification errors, how to interpret test results, and how to estimate prevalence using test results. These issues are examined in detail here by considering the factors that dictate the quality of a screening program. Some real data examples are used to illustrate the importance of this consideration in designing programs to achieve the desired goals. The rationale behind the common two-step sequential protocol in HIV screening is examined to point out its limitations under practical situations. Finally, the use of entropy in evaluating the informativeness of a screening program is discussed.


Joint influence of fat and lean body composition compartments on femoral bone mineral density in premenopausal women. Body composition (fat and lean compartments) and bone mineral density were measured in 246 healthy premenopausal women, aged 20-40 years, residing in Tecumseh, Michigan. Body composition was measured using four-point bioelectrical impedance and values for fat and lean compartments categorized into tertiles. Additionally, each woman was classified into one of nine different cells based on her location within a 3 x 3 table which reflects the joint distribution of both fat and lean compartments. Bone mineral density of the proximal femur, including the femoral neck and trochanter, was measured using dual photon densitometry. The mean femoral neck bone mineral density values increased significantly and linearly for each tertile of muscle mass (0.90, 0.95, and 1.02 g/cm2, p less than 0.0002). Femoral bone mineral density increased significantly but not linearly as the fat compartment progressed from the lowest to the highest tertile (0.95, 0.93, and 0.99 g/cm2). Bone mineral density of the proximal femur was similar and significantly greater in the high muscle/low fat and high muscle/high fat body composition subgroups compared with bone mineral density in the seven other groups. However, women in the high muscle/low fat subgroup had substantially lower mean weight (67 vs. 91 kg, p less than 0.0001) and mean Quetelet index (22.1 vs. 33.7 kg/m2, p less than 0.0001) than women in the high muscle/high fat subgroup. Bone mineral density values were similar and significantly lower in the following body composition cells: low muscle/low fat, low muscle/medium fat, and low muscle/high fat. Similar findings were observed at the trochanteric site. Low muscle is a risk factor for low bone mineral density in young adult women while higher fat is protective only when associated with substantial muscle.


Preterm delivery and low birth weight among first-born infants of black and white college graduates. Reproductive outcomes were investigated in black and white female college graduates, presumed to be of similar socioeconomic status and similar risk profile with respect to environmental factors. Data were gathered by mail survey from graduates (1973-1985) of four Atlanta, Georgia, colleges between February and June 1988. Of 6,867 alumnae to whom questionnaires were mailed, 3,084 responded. A follow-up study of black nonrespondents yielded responses from 14% (335) of those who did not respond to the mail survey. For all graduates with a first live born at the time of survey (n = 1,089), the rates of preterm delivery, low birth weight, and infant mortality were 80.8, 82.6, and 14.6 per thousand births (primigravida), respectively. Compared with white graduates, black graduates had 1.67 times the risk of preterm delivery and 2.48 times the risk of low birth weight. Measures of social and economic status differed significantly by race. However, adjustment for these variables did not reduce the estimated risk for black graduates compared with whites. Analysis of the nonresponder survey suggested that respondent data alone overestimates the incidence of adverse outcomes in blacks; using nonresponder data, relative risks of 1.28 (preterm delivery) and 1.75 (low birth weight) were calculated as lower limits of the increased risk for blacks.


Infant resuscitation is associated with an increased risk of left-handedness. The etiology of left lateral preference is not well understood, but some studies have suggested that it can be caused by complications at birth. The authors used data from the Child Health and Development Study, a large prospective study of pregnancy and child development conducted 1959-1966 in the San Francisco Bay Area of California, to examine the association between specific birth stressors and hand and foot preference. The study population consisted of 6,968 5-year-olds with no severe congenital abnormalities, and the authors controlled for potential demographic confounders and familial left-handedness. Infants who required resuscitation after delivery or who were twins or triplets were about twice as likely to demonstrate left hand preference at age 5 years (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.3-2.5, and OR = 2.2, 95% CI 1.2-4.0, respectively). Left-footedness was also significantly associated with the same stressors. No other individual stresses were significantly associated with left-lateral preference, and a composite measure indicated only a weak association. Although males, blacks, and those with left-handed siblings are more likely to show left lateral preference, these variables do not confound the association between birth stress and left lateral preference. These results indicate that specific types of birth stress are strongly associated with left hand and foot preference; however, much of the left laterality in non-clinical populations remains unexplained.


Allergy and cancer: organ site-specific results from the Adventist Health Study. The relation between allergy and risk of cancer was evaluated in a cohort study of 34,198 Seventh-day Adventists in California. Information on prevalence of asthma, hay fever, and reactions to chemicals, medications, bee stings, and poison oak (or ivy) was obtained by questionnaire in 1976. The reported allergies must have been serious enough to require treatment by a physician. The cohort was then followed for 6 years (1977-1982). Both stratified analysis and Cox proportional hazards regression analyses were utilized to evaluate the relation of allergy to cancer after taking into account several potentially confounding variables. For all cancer sites combined in males, there was a 33% increased risk associated with reaction to medications. In contrast, among females, reaction to medications was associated with a 21% decrease in risk. Both results were statistically significant. Prostate and breast cancer risk were elevated in persons who reported any type of allergic history, as was risk of lymphatic or hematopoietic cancers and sarcoma. For each of these types of cancer, risk increased with increasing numbers of allergies. However, ovarian cancer risk was decreased in persons with any allergic history and increasing numbers of allergies was associated with decreasing risk of this form of cancer. These results suggest that the association between allergy and cancer is complex and depends on the specific allergy and the specific organ site under consideration.


Influenza vaccine effectiveness in preventing hospitalization for pneumonia in the elderly. During the winter of 1989-1990, influenza type A(H3N2) circulated widely, causing excess morbidity and mortality nationwide. From November through April, 1989-1990, hospitalized cases of pneumonia and influenza occurring among noninstitutionalized individuals 65 or more years of age were identified by 20 acute care hospitals in southern lower Michigan. These cases were group matched on age, sex, race, and zip code to randomly sampled, community-based controls from a comprehensive listing of Medicare beneficiaries residing in the study area. Self-reported data were collected from cases and controls on influenza vaccine status for the 1989-1990 season and on a number of other factors which could have influenced vaccination status or outcome. Questionnaires were completed by 1,907 individuals, 449 of whom were cases, resulting in an overall response rate of 76%. A community-based influenza surveillance system was implemented to determine the timing and intensity of viral activity and influenza-like illness. Vaccine effectiveness in preventing overall pneumonia and influenza hospitalizations was estimated by logistic regression. During the 3-month period of surveillance-confirmed peak influenza type A(H3N2) circulation, vaccine effectiveness was 45% (95% confidence interval 14-64, p = 0.009). However, during the 3-month period of low or absent virus activity, identical methodology and model specification resulted in an effectiveness estimate of 21% that was not statistically different from zero (p = 0.36). The effectiveness determined during the peak period of virus circulation is felt to be a conservative estimate, since agents other than influenza are responsible for pneumonia and influenza hospitalizations, even during times of peak influenza activity.


Interpretation and estimation of vaccine efficacy under heterogeneity. Interpretation and estimation of vaccine efficacy is complicated when the vaccine effect is heterogeneous across vaccinated strata. If a person has a certain susceptibility, or probability of becoming infected conditional on a specified exposure to infection, then one effect of a vaccine would be to reduce that susceptibility, possibly to zero. Vaccine efficacy is a function of the relative susceptibilities in the vaccinated and unvaccinated persons. Under heterogeneity of vaccine effect, a general expression for a summary vaccine efficacy parameter is a function of the vaccine efficacy in the different vaccinated strata weighted by the fraction of the vaccinated subpopulations in each stratum. Interpretation and estimability of the summary vaccine efficacy parameter depends on whether the strata are identifiable, and whether the heterogeneity is host- or vaccine-related. Bounds are derived for the summary vaccine efficacy when the strata are not identifiable for the case of an outbreak of an acute infectious disease. The upper bound assumes that everyone is equally affected by the vaccine, and the lower bound assumes that some are completely protected while others have no protection. The biologic interpretation of the two bounds is different.


Variation and covariates of the number of benign nevi in adolescents. Melanocytic nevi of diameter greater than or equal to 2 mm were counted on most of the skin surface of 349 adolescents aged 14-15 years of European race or ethnicity in Dunedin, New Zealand. Total counts are described by means of a form of Poisson-error log-linear modeling suitable for data showing unexplained variation (NE Breslow, Appl Statist 1984;33:38-44). There were marked interpersonal variation in the number of nevi; only some was attributable to observed factors. The mean and median counts were 23.8 and 18 nevi, respectively. The estimated ratio of the number of nevi for females compared with males was 0.7 (95% confidence interval (CI) 0.6-0.8). Greater amounts of sunbathing were associated with greater numbers of nevi. Hair and eye color, socioeconomic status, and sunburn history did not show statistically significant effects. Time since menarche and shaving status also showed no effects. Lack of suntan was associated with lower counts. Freckling was positively correlated with higher counts; the severe freckling group had an estimated ratio of 1.9 (95% CI 1.3-2.8) compared with those with no or very few freckles. The results are consistent with the hypothesis that ultraviolet radiation exposure from recreational sun exposure positively influences the total burden of nevi in normal subjects. Comparison with other epidemiologic studies suggests that the typical ultraviolet radiation dose-nevus yield curve might be steeper in males than females. Unexplained variation of nevus count may reflect heterogeneity of constitutional factors not yet measured in epidemiologic studies.


Effect of nondifferential misclassification on estimates of odds ratios with multiple levels of exposure. Nondifferential misclassification of exposure status with a dichotomous exposure will produce biased estimates of odds ratios such that the misclassified odds ratio is always biased toward the null value. However, when an exposure classification has more than two levels, empirical data indicate that the direction of bias is less predictable. Analysis of an algebraic model of multi-level exposure misclassification reveals that all odds ratios based on the misclassified data are constrained between the nonmisclassified odds ratio for the most extreme category and the inverse of this value. This implies that the misclassified odds ratio for the most extreme exposure level will be biased toward the null but that odds ratios for intermediate levels of exposure could be biased away from the null value. Further, the amount of bias depends not only on the misclassification rates but also on the distribution of subjects across exposure levels. If it is assumed that misclassification is likely to occur only between adjacent categories, the range of possible misclassified odds ratios is reduced but is still sufficient to permit serious distortion of an exposure-response relation. In general, biases away from the null occur only for intermediate levels of exposure. Reversal of an exposure-response relation is more likely to occur when misclassification rates are high (especially between nonadjacent levels) and when the number of exposure levels is low.


Birth defects in Norway by levels of external and food-based exposure to radiation from Chernobyl. In Norway, external doses of radiation resulting from fallout from the Chernobyl nuclear accident were estimated from detailed measurements, including soil deposition patterns. Internal doses were estimated from measurements of radioactive cesium in meat and milk supplies. The doses were calculated as average monthly doses for each of 454 municipalities during 36 consecutive months after the accident in spring 1986. Prospectively collected data on all newborns listed in the Medical Birth Registry of Norway who were conceived in the period May 1983-April 1989 were used to assess possible dose-response relations between estimated external and food-based exposures and congenital malformations and some other conditions. A positive association was observed between total radiation dose (external plus food-based) and hydrocephaly, while a negative association was observed for Down's syndrome. However, an important conclusion of the study was that no associations were found for conditions previously reported to be associated with radiation, i.e., small head circumference, congenital cataracts, anencephaly, spina bifida, and low birth weight. Potential sources of bias, including exposure misclassification and incomplete ascertainment of cases, are discussed.


Mortality among workers exposed to polychlorinated biphenyls. On the basis of evidence from animal studies, polychlorinated biphenyls (PCBs) are considered potentially carcinogenic to humans. However, the results of studies in human populations exposed to PCBs have been inconsistent. The authors conducted a retrospective cohort analysis (1957-1986) comparing the mortality of 3,588 electrical capacitor manufacturing workers with known exposure to PCBs with age-, sex-, and calendar time-specific mortality rates for all whites in the United States. Proportional hazards modeling was also performed to examine the association between cumulative PCB exposure and site-specific cancer mortality. All-cause mortality (192 deaths observed, 283.3 expected) and total cancer mortality (54 deaths observed, 63.7 expected) were lower than expected. More deaths were observed than expected for malignant melanoma (8 observed, less than 2.0 expected) and cancer of the brain and nervous system (5 observed, 2.8 expected). The average estimated cumulative dose for the cases of brain cancer (22.9 units) was greater than for other workers (12.9 units), but the 95% confidence intervals around this difference were broad. The risk of malignant melanoma was not related to cumulative PCB exposure. These results provide some evidence of an association between employment at this plant and malignant melanoma and cancer of the brain. The possibility that the results are due to chance, bias, or confounding cannot be excluded.


Influence of paternal characteristics on the risk of low birth weight. The combined effects of maternal and paternal factors on the risk of delivering low birth weight (less than 2,500 g) and very low birth weight (less than 1,500 g) infants were examined among married parents. Using 1984-1988 natality data compiled by the National Center for Health Statistics, the authors found paternal education and race to have independent effects on the risks of low birth weight and very low birth weight after adjustment for maternal characteristics. The odds of low and very low birth weight decreased with increasing paternal education. Adjustment for paternal education decreased the effect of maternal education on the risks of low and very low birth weight. Additionally, the examination of paternal race led to the identification of a subgroup of married black women with lower risks of low and very low birth weight than married black mothers overall. These data suggest that paternal characteristics should be used, in addition to maternal characteristics, to describe the risks of low and very low birth weight.


Reproductive factors and risk of myocardial infarction. The relation of reproductive factors to risk of myocardial infarction in women aged 45-69 years was examined in a case-control interview study carried out in Massachusetts from 1986 to 1990. Each of 858 cases of first myocardial infarction was age-matched with a control from the same precinct of residence. Conditional logistic regression was used to control the matching factors and the major known and suspected risk factors for coronary heart disease. For parous women compared with nulliparous women, the estimated relative risk of myocardial infarction was 1.8 (95% confidence interval (CI) 1.0-3.3). Among parous women, the relative risk estimate for five or more births relative to fewer births was 1.4 (95% CI 1.0-2.0); the estimate for a first birth before age 20 relative to a later age at first birth was 1.7 (95% CI 1.1-2.6). The greatest increase in risk was observed for women who had both an early age at first birth and five or more children. However, confounding by factors related to socioeconomic status may have contributed to the results. Compared with women who had a natural menopause at age 50 or older, women who reached the menopause before age 45 were at increased risk regardless of type of menopause: The estimated relative risks were 2.1 (95% CI 1.3-3.2), 1.7 (95% CI 1.0-2.7), and 1.7 (95% CI 1.0-2.8) for early natural menopause, bilateral oophorectomy, and hysterectomy with retention of one or both ovaries, respectively. These results suggest that early cessation of ovulatory function, whether due to natural causes or to surgery, increases the risk of myocardial infarction. Age at menarche was not related to myocardial infarction risk.


Ingested arsenic, keratoses, and bladder cancer. A cohort of 478 patients treated with Fowler's solution (potassium arsenite) in Lancashire, England, during the period 1945-1969 and previously followed until January 1, 1980, was followed for an additional 11 years. A significant excess of bladder cancer mortality occurred (observed/expected ratio = 5/1.6; p = 0.05). No excess was found for other causes of death. In a subcohort of 142 patients examined for signs of arsenicism around 1970, all 11 subsequent cancer deaths occurred in those with signs of arsenicism (p = 0.0009).


Reduced cancer morbidity and mortality in a prospective cohort of women with distal forearm fractures. At the Department of Orthopedics of University Hospital, Lund, Sweden, cancer incidence and overall and cause-specific mortality were studied in a prospective cohort of 677 women who had experienced a fracture of the distal forearm in 1974 or 1975. The women were followed through population-based population, cancer, and death registries in southern Sweden. There was a significant reduction in overall cancer incidence (66 cases observed vs. 90.21 expected), breast cancer incidence (11 cases observed vs. 20.31 cases expected), and incidence of tumors of the female genital tract (5 cases observed vs. 11.84 expected). Overall mortality was also reduced (146 cases observed vs. 191.69 cases expected), and rates of death from circulatory disease (79 cases observed vs. 111.49 expected) and malignant tumors (30 cases observed vs. 40.41 expected) were both lower than expected.


Blood pressure and twenty-year mortality in the city of Bergen, Norway. A blood pressure survey was carried out in 1963 in the city of Bergen, Norway. The relation between 20-year mortality and blood pressure in 52,064 participants aged 30-89 years at examination was analyzed. Increased blood pressure was related to increased mortality from coronary heart disease, stroke, and all causes in all age groups except the oldest, where a more irregular pattern was present. The relative risks decreased with age at screening, while the absolute increase in mortality with increasing blood pressure was greatest in persons aged 60-69 or 70-79 years at screening. A log-linear relation between systolic blood pressure and coronary heart disease and stroke mortality was seen in both men and women. An upturn in total mortality at low systolic blood pressures was suggested in the groups aged 60 years or more at screening. An upturn, or leveling off, was also seen at low diastolic blood pressures for total deaths and stroke deaths in both men and women.


The increase in blood pressure with age and body mass index is overestimated by conventional sphygmomanometry. This cross-sectional study investigated whether the technique of blood pressure measurement used (conventional sphygmomanometry vs. ambulatory monitoring) affects the relation between blood pressure and both age and body mass index. Two independent data sets were analyzed. The first comprised 328 subjects (48% men) drawn from the population of a small Belgian town, and the second comprised 776 Irish bank employees (51% men). Age ranged from 17 years to 81 years, and body mass index (weight (kg)/height (m)2) ranged from 16.6 to 40.2. Twenty-four-hour ambulatory blood pressure was lower than blood pressure measured by a nurse in both the Belgian population sample (118/71 mmHg vs. 122/73 mmHg) and the Irish employees (118/72 mmHg vs. 119/76 mmHg). When blood pressure was measured by an observer, the well-established relations between systolic and diastolic blood pressure and both age and body mass index were evident. When the analyses were repeated using 24-hour measurements, the increment (cross-sectionally assessed) in blood pressure with age was weaker, especially in young and middle-aged subjects (20-60 years), while the increase in blood pressure with body mass index was also reduced. The within-subject differences between the conventional and ambulatory blood pressure measurements increased with older age and greater body mass index. Several other relations with blood pressure as the response variable may require revision in light of the present findings.


The risk approach to intervention in severe malnutrition in rural Bangladesh. To determine whether clinical marasmus occurs in small groups of children from easily recognizable high-risk households, the authors conducted a case-control study to identify risk indicators that may be used in targeted interventions. Cases were children whose mid-upper arm circumference measured less than 110 mm, and controls were children matched for age and sex with arm circumferences greater than 120 mm. Between June 1988 and June 1989, 164 such pairs of children aged 1-4 years were studied in Matlab, Bangladesh. Conditional logistic regression analysis showed an increased risk of marasmus among children from families with other children under 5 years of age (odds ratio = 2.80, 95% confidence interval 1.56-5.02) and children who consumed formula foods (odds ratio = 18.81, 95% confidence interval 4.15-85). Higher maternal education was associated with reduced risk of marasmus. Further examination of these risk indicators suggests that the resources saved through targeting fewer households will be negated by missing many children with marasmus. The authors conclude that the application of targeted interventions against marasmus, using the risk approach, is unlikely to be efficient.


Efficiency loss from categorizing quantitative exposures into qualitative exposures in case-control studies. In the analysis of data from case-control studies, quantitative exposure variables are frequently categorized into qualitative exposure variables, such as quarters. The qualitative exposure variables may be scalar variables that take the median values of each quantile interval, or they may be vectors of indicator variables that represent each quantile interval. In a qualitative analysis, the scalar variables may be used to test the dose-response relation, while the indicator variables may be used to estimate odds ratios for each higher quantile interval versus the lowest. Qualitative analysis, implicitly and explicitly documented by many epidemiologists and biostatisticians, has several desirable advantages (including simple interpretation and robustness in the presence of a misspecified model or outlier values). In a quantitative analysis, the quantitative exposure variables may be directly regressed to test the dose-response relation, as well as to estimate odds ratios of interest. As this paper demonstrates, quantitative analysis is generally more efficient than qualitative analysis. Through a Monte Carlo simulation study, the authors estimated the loss of efficiency that results from categorizing a quantitative exposure variable by quartiles in case-control studies with a total of 200 cases and 200 controls. In the analysis of the dose-response relation, this loss is about 30% or more; the percentage may reach about 50% when the odds ratio for the fourth quartile interval versus the lowest is around 4. In estimating odds ratios, the loss of efficiency for the second, third, and fourth quartile intervals versus the lowest is around 90%, 75%, and 40%, respectively. The authors consider the pros and cons of each analytic approach, and they recommend that 1) qualitative analysis be used initially to estimate the odds ratios for each higher quantile interval versus the lowest to examine the dose-response relation and determine the appropriateness of the assumed underlying model; and 2) quantitative analysis be used to test the dose-response relation under a plausible log odds ratio model.


A multistate outbreak of sporotrichosis associated with sphagnum moss. In the spring of 1988, the largest documented US outbreak of cutaneous sporotrichosis to date occurred, with 84 cases among persons from 15 states who were exposed to Wisconsin-grown sphagnum moss used in packing evergreen tree seedlings. In New York State, 13 cases occurred among 109 forestry workers. All 13 cases occurred among 76 workers who had handled evergreen seedlings and moss (attack rate = 17%). For those exposed to evergreens and moss, the risk of infection increased as worktime exposure to moss increased (attack rates: less than 10 hours, 8%; 10-19 hours, 12%; greater than 19 hours, 33%). While environmental samples of moss from the Wisconsin supplier were negative, Sporothrix schenckii was cultured from multiple samples of the sphagnum moss obtained from one of six Pennsylvania tree nurseries, representing the nursery that was identified as the source for 79 (94%) of the moss-associated cases. Differences in tree-handling procedures at this nursery--including the use of 1- to 3-year-old moss to pack seedlings, use of a pond water source to wet the moss, use of an organic polymer gel on the seedling root system, and underground storage and longer storage of moss-packed seedlings before shipping--suggested possible explanations for the association. Efforts to prevent sporotrichosis among persons handling evergreen seedlings should include the use of alternate types of packing material (e.g., cedar wood chips or shredded paper) and protective clothing such as gloves and long-sleeved shirts.


Interspecies transmission and reassortment of influenza A viruses in pigs and turkeys in the United States. Genetic reassortment between influenza A viruses in humans and in animals and birds has been implicated in the appearance of new pandemics of human influenza. To determine whether such reassortment has occurred in the United States, the authors compared the genetic origins of gene segments of 73 swine influenza virus isolates (1976-1990), representing 11 states, and 11 turkey virus isolates (1980-1989), representing eight states. The host origin of gene segments encoding the internal proteins of H1N1 swine and turkey influenza viruses was identified by developing a dot-blot assay. All gene segments of swine influenza viruses were characteristic of influenza virus genes from that species, indicating that pigs may not be frequent participants in interspecies genetic exchange and reassortment of influenza viruses in the United States. In contrast, 73% of the turkey influenza virus isolates contained genes of swine origin. One turkey isolate was a reassortant having three genes characteristic of avian influenza virus and three of swine origin. These findings document a high degree of genetic exchange and reassortment of influenza A viruses in domestic turkeys in the United States. The molecular biologic techniques used by the authors should aid future epidemiologic studies of influenza pandemics.


Laboratory and clinical aspects of inherited thrombotic disorders. The laboratory evaluation of patients with recurrent thrombosis is frequently frustrating, with a low diagnostic yield obtained despite extensive testing. The likelihood of reaching a diagnosis in these patients can be increased by considering diagnostic possibilities usually overlooked and by using assays optimal for their detection. This review summarizes clinical and laboratory issues important in inherited thrombotic disease and discusses practical aspects and a strategy for laboratory testing. New information is provided on the fibrinolytic disorders that may be a common cause of recurrent thrombosis.


Inefficacy of extracorporeal photochemotherapy in the treatment of B-cell chronic lymphocytic leukemia: preliminary results. Because extracorporeal photopheresis has been shown to be clinically effective in Sezary syndrome, a disease characterized by a circulating malignant clone, we initiated a pilot study of its use in B-cell chronic lymphocytic leukemia (B-CLL) to see if it could be similarly effective. We treated three patients with Rai stage III and IV B-CLL with photopheresis (3 consecutive days a week every 3 weeks) and followed serial clinical and immunologic parameters. While we noted no major toxicity, there was neither clinical response to treatment nor marked improvement in white counts or mitogen assays. We conclude that photopheresis was not effective in inducing remission in this pilot study of advanced stage B-CLL patients.


Effectiveness of high-dose intravenous immunoglobulin in a case of acquired von Willebrand syndrome with chronic melena not responsive to desmopressin and factor VIII concentrate. A patient with benign monoclonal IgG lambda paraproteinemia, acquired von Willebrand syndrome (AVWS), and chronic melena successfully responding to high-dose intravenous immunoglobulin (lvlg) is reported. Coagulation parameters at admission were APTT (ratio) 1.68; VIII:C 11 IU/dL; vWF:Ag 7 IU/dL:Ricof less than 3 IU/dl. RIPA was greater than 1.8 mg/ml, and bleeding time (BT) was prolonged (18 min). No evidence for an in vitro inhibitor against the VIII/vWF complex was observed. VIII/vWF measurements showed a short-lived increase after both DDAVP and Hemate P, and BT was transiently normalized. After intravenous Ig (1 g/kg for 2 days), VIII/vWF measurements, hemostatic parameters and multimeric pattern were completely corrected (VIII/C 106 IU/dl, vWF:Ag 168 IU/dl, RiCof 147 IU/dl, APTT ratio 0.89, BT 5'), with a return to pre-infusion values after 15 days. Hemoccult test became negative and packed red cell transfusions, of which 130 units were administered during the last year, were no longer required. After 18 months the patient is on maintenance treatment with repeated courses of Ig, at 3 to 4-week intervals based on VIII/vWF and BT monitoring.


A new case of acute lymphoblastic leukemia B-cell type with chromosomal rearrangements involving the T-cell receptor breakpoint at band 14q11. A patient with B-cell acute lymphoblastic leukemia (ALL) and a translocation t(8;14) (q24;q11) is described. Translocation t(8;14)(q24;q32) is commonly associated with B-cell leukemia; nevertheless, translocations affecting chromosome 14 at band q11 are associated with T-cell malignancies, since the locus 14q11 contains genes that encode for the alpha and delta chains of the T-cell receptor (TCR). This finding points to the idea that the association between 14q11 rearrangements and T-cell neoplasia is less than complete.


Role of endothelin in disseminated intravascular coagulation. We examined the changes in plasma levels of endothelin-1 (ET-1), a potent vasoconstrictor peptide, in 47 cases of disseminated intravascular coagulation (DIC) to investigate the role of ET-1 in DIC and its relation to multiple organ failure (MOF). A significant elevation of plasma levels of ET-1 was observed in some cases of DIC, especially in patients with sepsis, blastic crisis of chronic myelogenous leukemia, and cancer. However, no such significant elevation was observed in patients with acute promyelocytic leukemia (APL), acute leukemias except for APL, or non-Hodgkin lymphoma. Plasma levels of ET-1 were higher in patients with DIC with MOF than in those without MOF. Although the levels of ET-1 were decreased or remained low with clinical improvement in most DIC patients, the levels were further increased or remained high in patients who showed no improvement in DIC. It is suggested that ET-1 must play an important role in further progression of MOF with the vasoconstriction and microcirculatory disorders.


5-Aminolevulinate synthase in sideroblastic anemias: mRNA and enzyme activity levels in bone marrow cells. To examine the role of 5-aminolevulinate synthase (ALAS) in the pathogenesis of sideroblastic anemias, levels of mRNAs for erythroid and housekeeping ALAS isozymes were examined, and total ALAS activity was assessed in bone marrow cells. In two patients with X-linked sideroblastic anemia the levels of mRNA for erythroid ALAS as well as for alpha and beta globin appear to be decreased while levels of mRNA for glycophorin A in both patients were the same as in normal individuals. However, amounts of housekeeping ALAS mRNA were increased two- to threefold in these patients. Total ALAS activity was also increased two- or threefold, perhaps reflecting increased transcription of the housekeeping gene in response to diminished cellular heme in erythroid cells and/or enhanced translation of the erythroid isoform in response to iron accumulation. In a third patient with X-linked sideroblastic anemia ALAS activity was low but increased to twice the normal value after pyridoxine administration, suggesting a structural defect of the enzyme. In a fourth patient, with isolated congenital, pyridoxine-responsive sideroblastic anemia, the erythroid ALAS mRNA was normal and a low enzyme activity was strikingly enhanced by pyridoxal-phosphate albeit to subnormal levels. In idiopathic acquired sideroblastic anemia, ALAS mRNA for both isozymes was normal and enzyme activity was slightly elevated. These observations thus reflect heterogeneous aberrations of erythroid heme synthesis in the various types of sideroblastic anemia and suggest that defects involving erythroid ALAS underlie at least some of them.


Procoagulant activity of endotoxin or tumor necrosis factor activated monocytes is enhanced by IgG from patients with lupus anticoagulant. The effect of lupus anticoagulant (LA) positive plasma on the expression of human monocyte procoagulant activity (PCA) was studied. LA positive plasma were able to enhance the endotoxin or TNF alpha induced monocyte associated PCA. The monocyte PCA had the characteristic of tissue factor activity (factor VII, factor X dependence). The enhancement of monocyte PCA could be confirmed using purified LA positive IgG. The stimulating effect was supported by the F(ab')2 fragments.


Dyserythropoiesis in iron-deficiency anemia: ultrastructural reassessment. Iron deficiency is usually included among the causes of acquired dyserythropoiesis. This concept was derived mainly from light microscopic studies. To reassess such a notion at ultrastructural level, a transmission electron microscopic evaluation of bone marrow was performed in seven patients with iron-deficiency anemia. In contrast to the widely accepted concept, derived from light microscopic studies, only a small proportion (2-4%, not different from controls) of erythroblasts displayed some of the features of nuclear dyserythropoiesis. On the contrary, when examining the cytoplasm, we found a significantly increased number of void ropheocytotic vesicles in the majority of late erythroblasts as compared to controls (P less than 0.001). This feature may be considered as an ultrastructural marker of iron deficiency and is consistent with the present knowledge on transferrin-mediated delivery of iron to the cell.


Pseudoxanthoma elasticum-like skin lesions and angioid streaks in beta-thalassemia. One hundred patients with homozygous or doubly heterozygous beta-thalassemia (62 with the major form and 38 with beta-thalassemia intermedia) were examined for signs of Pseudoxanthoma elasticum (PXE). Diagnostic skin lesions were found in 16 patients with either form of the basic disease. Twenty percent of all patients had angioid streaks (AS); both PXE skin lesions and AS were found in 10% of the patients; in all, 26% had either one or both of these manifestations. A positive correlation was found between the presence of one or both types of lesion and age of the patients (P = 0.032); there were no differences as regards ferritin and hematocrit levels, number of transfused units, chelation therapy, and splenic status between patients with PXE/AS findings and those without. The pathogenesis of these connective tissue manifestations at such a high frequency in beta-thalassemia is not clear; the possibilities of it's being acquired or inherited are discussed, the former being considered to be the more economical interpretation.


Inefficacy of intravenous immunoglobulin in patients with low-risk thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome. To assess the efficacy of intravenous immunoglobulin (IVIG), in comparison with plasma exchange (PE), in the treatment of patients with thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome (TTP/HUS). Prospective, nonrandomized comparative study. Hematology department in a general hospital. 17 consecutive adult patients, six of them pregnant, with diagnosis of TTP/HUS. Three had a severity score at diagnosis less than or equal to 4 and were treated with IVIG and 14 had a severity score of greater than or equal to 5 and/or were pregnant and received PE. The response was evaluated after 5 days of therapy. Complete remission was obtained in 0/3 cases treated with IVIG and 10/14 (71%) with PE (Fisher's exact test P = 0.05). Three patients died for widespread TTP-HUS, and four had persistent disease. In three of the four resistant patients, complete remission was obtained by further PE but not by further IVIG. The overall remission rate was 76% (13/17). Our study does not confirm the utility of IVIG in the management of TTP-HUS, as suggested by earlier single case reports.


Influence of calcium permeabilization and membrane-attached hemoglobin on erythrocyte deformability. The present study was designed to evaluate the influence of intracellular calcium [Ca]i regulated membrane attached hemoglobin (Hbm) on the deformability of human RBC and ghosts. [Ca]i of RBC was elevated via the ionophore A23187 (10 microM); the deformability of RBC and resealed ghosts was determined via measuring RBC and ghost transit times through 5 microns diameter pores with the Cell Transit Analyzer (CTA). Salient results included: (1) significantly increased RBC levels of Hbm following ionophore treatment; (2) elevated Hbm with increasing lysing medium calcium concentration (0-5 mM); (3) decreased deformability of both intact RBC and ghosts with increasing Hbm and significant (P less than 0.02 or better) linear relationships between Hbm and RBC or ghost transit times; and (4) an increased sensitivity to ionophore treatment/membrane attached hemoglobin for the higher percentiles of the CTA transit time distribution (i.e., for more rigid subpopulations). Our results thus indicate that calcium-induced interaction of hemoglobin with the RBC membrane produces cellular rheological changes; in addition, they demonstrate the usefulness of the CTA system in measuring both average RBC rheologic behavior and the distribution of cellular rheologic properties within an erythrocyte population.


Treatment of acute myeloid leukemia in the elderly with low-dose cytarabine, hydroxyurea, and calcitriol. Twenty-nine patients aged 62-82 years with acute myeloid leukemia (AML) were treated with a 21-day course of continuous infusion cytarabine, oral hydroxyurea, and 1,25-dihydroxyvitamin D3 (calcitriol). Ten patients had an antecedent myelodysplastic syndrome. Calcitriol was continued as the only postremission therapy. Thirteen patients (45%) obtained a complete remission, and 10 patients (34%) had a partial response for an overall 79% response rate. There were three early deaths. The median remission duration was 9.8 months. Overall median survival was 12 months for all patients and 14 months for responding patients. All responding patients had marked bone marrow hypoplasia. Twenty patients received part or all of their chemotherapy as outpatients. This regimen has acceptable toxicity and can result in prolonged remissions in elderly, high-risk patients with AML. The favorable results may be related to the synergistic effect of hydroxyurea, cytarabine, and calcitriol.


Accessory spleen in recurrent chronic immune thrombocytopenic purpura. From 1969 to 1985 we discovered accessory spleens in 8 patients with chronic immune thrombocytopenic purpura (ITP) who relapsed or failed after splenectomy. Imaging of accessory spleen used a liver spleen scintigraphy with heat-treated RBC labeled with Tc-99m. Platelet kinetic studies with 51Cr or 111In, including sequestration index, were performed. Five patients had accessory splenectomy. Disappearance of bleeding symptoms was achieved in the 5 splenectomized patients but with only partial response of platelet counts. These results are discussed in the context of diagnosis and therapeutic management of accessory spleens in patients with chronic immune thrombocytopenic purpura who relapsed or failed after splenectomy.


Molecular basis of beta thalassemia in the south of Thailand. A total of 103 beta thalassemia genes from 78 children (45 with Hb E/beta thalassemia, 8 with beta thalassemia heterozygotes, and 25 with homozygous beta thalassemia) were analyzed using dot-blot hybridization of the polymerase chain reaction-amplified DNA and direct DNA sequencing. Nine mutations were characterized in 98/103 (95%) of beta thalassemia alleles, of which six (a 4 bp deletion in codons 41-42, a G-C transition at position 5 of IVS-1, A-G transition at codon 19, an A-T transition at codon 17, an A-G transition at position -28 upstream of the beta globin gene, a G-T transition at position 1 of IVS-1), accounted for 92%. The spectrum of beta thalassemia mutations in Chinese Thai is similar to that reported among the Chinese from other parts of the world. The distribution of beta thalassemia mutations in Muslim Thai is similar to that reported among Malaysians. The most common beta thalassemia mutation in Thai and Chinese Thai patients is the frameshift mutation at codons 41-42, in comparison with the Muslim Thai in whom the G-C transition at position 5 of the IVS-1 mutation predominates. The heterogeneity of molecular defects causing beta thalassemia should aid in the planning of a prenatal diagnosis program for beta thalassemia in the South of Thailand.


Leukemic manifestation in a case of alpha-chain disease with multiple polypoid intestinal lymphocytic lymphoma. We describe a female aborigine from Taiwan with alpha-chain disease associated with multiple polypoid intestinal lymphocytic lymphoma and leukemic manifestation. Initially, the patient experienced intermittent diarrhea, abdominal pain, and leukemic manifestation. No evidence of bone marrow involvement was found. Alpha-chain protein was demonstrated in the serum. Gastroendoscopy and a series of radiographs of the small intestine revealed multiple polypoid tumors involving the entire length of the small intestine. Duodenal biopsy showed diffuse lymphocytic lymphoma. Immunohistochemical staining of tumor samples revealed features typical of alpha-chain disease. Cytogenetic analysis showed the same abnormal karyotypes of neoplastic clones in intestinal tumor cells and in circulating leukemic cells. The data suggest that alpha-chain disease can present initially with intestinal multiple polypoid lymphocytic lymphoma and leukemic manifestation without evidence of bone marrow involvement. The data also support the homing theory of lymphomas from mucosa-associated lymphoid tissue.


Influence of clinical and histological features on actuarial renal survival in adult patients with idiopathic IgA nephropathy, membranous nephropathy, and membranoproliferative glomerulonephritis: survey of the recent literature. The most recent studies, using the actuarial life-table technique, of the problem of long-term renal outcome and the factors that influence it in adult patients with one of the three most common types of chronic idiopathic immune complexes-mediated glomerulonephritis (IgA nephropathy [IgAN], membranous nephropathy [MN], and type I membranoproliferative glomerulonephritis [MPGN]) are reviewed. In the last decade, renal survival 10 years after onset has become similar to adult patients with idiopathic IgAN (80% to 87%) and idiopathic MN (75% to 83%), because of improvement of the renal survival of patients with MN. Renal survival at 10 years is worse for adult patients with idiopathic type I MPGN (60% to 64%). There is no substantial difference in the average renal survival times between different geographical regions, with the exception of a better prognosis for idiopathic MN in Japan. The presenting clinical factors that most strongly predict subsequent poor outcome are similar for the three types of glomerulonephritis and are rather nonspecific: (1) severe proteinuria, (2) impairment of renal function, and (3) arterial hypertension. As for the histological features, the most powerful predictor of subsequent progression in all three types of glomerulonephritis is tubulointerstitial damage, suggesting that a cell-mediated immune process believed to occur there may independently influence outcome in glomerular diseases.


The uremic dyslipidemia: a cross-sectional and longitudinal study. Patients on maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) exhibit numerous disturbances of serum lipids and apoproteins that may contribute to their high cardiovascular mortality. Cross-sectional studies have found that lipid levels are inversely related to time on dialysis. However, it is not known whether this association is the result of the attrition of hyperlipidemic patients or a decrease in lipid levels over time in all patients. Additionally, few studies have investigated the effect of dialysis modality on the lipoprotein disturbances of uremia adjusting for the confounding influences of demographics, or nutritional and endocrine status. To address these issues, we undertook a cross-sectional and longitudinal study of lipids, apoproteins, and atherogenic risk ratios in patients maintained on HD and CAPD. Patients were enrolled in annual cohorts from 1987 to 1990 and monitored until 1991. A total of 196 HD and 77 CAPD patients were studied. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), apoprotein (apo) A-I, and apo B were measured on enrollment and remeasured annually in survivors through 1990. Using multivariate methods, we examined the relationship of the lipids, apoproteins, their respective ratios, and their changes over time, to a broad range of clinical factors and to mortality. Compared with HD patients, CAPD patients had significantly higher TC, apo A-I, and apo B, and a significantly lower apo A-I/apo B ratio. Serum albumin correlated directly with TC and apo B and inversely with apo A-I/apo B. For patients with normal serum albumin (> or = 3.5 g/dL [35 g/L]), CAPD patients had a significantly higher TC/HDL-C than HD patients; otherwise the ratios were similar for CAPD and HD. Independent influences on lipoprotein levels in HD and CAPD patients were also demonstrated for race, gender, and diabetes, but not for parathyroid hormone (PTH) levels. For both dialysis modalities, patients who died had significantly lower TC and apo B, and significantly higher apo A-I/apo B throughout their entire courses compared with survivors. In the subset of patients followed longitudinally for 2 or more years, apo B tended to decrease with time, but TC, HDL-C, and apo A-I were stable. The longitudinal changes in lipoproteins did not correlate with outcome or other factors. In conclusion, CAPD patients have more atherogenic lipoprotein profiles than HD patients. Improved visceral protein nutritional status, as defined by serum albumin level, is associated with hyperlipidemia and, especially vor CAPD, worsened atherogenic risk ratios.(ABSTRACT TRUNCATED AT 400 WORDS)


A trial of the prostaglandin E1 analogue, enisoprost, to reverse chronic cyclosporine-associated renal dysfunction. Cyclosporine (CYA) reduces the renal synthesis of prostaglandins of the E series (PGE). Analogue of PGE1 have been shown to mitigate the vasoconstriction and abnormal renal function of experimental acute CYA nephrotoxicity. We examined the hypothesis that the orally bioavailable PGE analogue enisoprost (EP) would improve renal function in renal transplant recipients chronically exposed to CYA. In a randomized double-blind study, 40 patients at two centers who were being monitored for 3 to 30 months after renal transplantation, were allocated to receive either EP 100 micrograms orally four times daily or placebo (P) for 2 weeks. CYA dosing was fixed at existing levels. There could be no evidence of concurrent acute renal injury, including that of acute rejection. Glomerular filtration rate (GFR) was measured by the clearance of radiolabeled DTPA, while effective renal plasma flow (ERPF) was measured as the clearance of p-aminohippuric acid (PAH). The acute effects of EP were examined twice, by comparing immediate postdose to predose values for GFR and ERPF on day 1 and again on day 14. Chronic effects were examined by comparing baseline (predose) values only for GFR and ERPF between days 1 and 14 and by an examination of creatinine clearances (CCR) on days 0, 14, and 21. At enrollment, patients were well matched for renal function (CCR:EP 47 +/- 5 v P 49 +/- 4 mL/min/1.73 m2; P = NS). Baseline demographics were similar, although patients treated with EP were older (46 +/- 2 v 36 +/- 3 years, mean +/- SEM, P = 0.003). CYA doses and blood levels did not change significantly.(ABSTRACT TRUNCATED AT 250 WORDS)


Renal hemodynamics in recent-onset type II diabetes. Glomerular hyperfiltration is thought to play an important role in the genesis of diabetic nephropathy. While hyperfiltration is well documented in early type I diabetes, the evidence for hyperfiltration in type II diabetes is conflicting. We investigated 16 nonproteinuric patients with recently diagnosed type II diabetes. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured as inulin clearance (CIN) and p-aminohippuric acid clearance (CPAH) using a constant infusion technique. Lean body mass was measured by densitometry (weighing under water). Renal hemodynamics were also measured in 31 healthy volunteers and six obese nondiabetic individuals. Median GFR in diabetics (133 mL/min/1.73 m2; range, 95 to 165) was significantly (P < 0.01) higher than in obese nondiabetic controls (median, 118; range, 95 to 139). Elevated GFR (ie, > 95th percentile of nonobese healthy controls) was found in 44% of patients. When GFR was factored for lean body mass, it was elevated in 50%. GFR did not correlate with fasting glucose, hemoglobin A1C (HbA1C), insulin-like growth factors, IGF-1 and IGF-2, or somatomedin-binding protein (SMBP). The findings document that hyperfiltration is common in recent-onset type II diabetics.


Evidence for activation of tubuloglomerular feedback following nephrectomy in human subjects. The intrarenal regulation of glomerular filtration rate (GFR) following a reduction in renal mass was evaluated in six normal subjects, studied before and 4 to 6 weeks after undergoing unilateral nephrectomy, performed for the purpose of living-related transplantation. The role of the tubuloglomerular feedback (TGF) system in regulating the final GFR on both occasions was assessed by determining the increase in GFR over baseline levels following blockade of TGF by a single dose of bumetanide, care being taken to replace sodium and water losses. Before donor nephrectomy, baseline GFR was 115 +/- 7 mL/min, which increased by 9.5% +/- 2.5% to 126 +/- 9 mL/min following the removal of TGF. Four to six weeks following donor nephrectomy, the baseline GFR was 83 +/- 8 mL/min, confirming significant hyperfiltration in the remaining kidney. After administration of bumetanide, the GFR increased by 15.6% +/- 3.1% to 96 +/- 9 mL/min. This greater fractional increase (P < 0.025) indicates an increase in tonic TGF activity in the uninephrectomized state compared with that demonstrated before nephrectomy. The results suggest that the hyperfiltration response following unilateral nephrectomy is limited by an appropriately activated TGF system. This phenomenon may be of importance in the maintenance of Na and water homeostasis, as well as limiting the pathological consequences that may result from, or be exacerbated by, an excessively high filtration rate in the remaining nephrons. Thus, dietary or therapeutic maneuvers that impair the TGF response may be best avoided following a reduction in renal mass.


Vancomycin elimination during high-flux hemodialysis: kinetic model and comparison of four membranes. Vancomycin clearance was measured in five patients during dialysis with cuprophane (CU), polysulfone (PS), cellulose triacetate (CT), and polyacrylonitrile (PAN) dialyzers. Vancomycin was significantly cleared during routine high-flux (HF) hemodialysis (HD) with the latter three membranes, but not by CU. Postdialytic rebound of serum vancomycin concentrations was noted following HF dialysis, necessitating use of a two-compartment pharmacokinetic model. Measurement of serum vancomycin concentration immediately postdialysis significantly overestimates intradialytic removal, possibly resulting in inappropriate dose adjustment. Vancomycin infusion during HF HD results in significant drug removal during its administration to the patient, complicating the calculation of an adequate dose.


Improved lipid profiles in patients undergoing high-flux hemodialysis. Hyperlipidemia is one of many atherogenic risk factors encountered by patients undergoing chronic hemodialysis (HD). We have studied lipid profiles in these patients and have found less hypertriglyceridemia in those undergoing high-flux HD than those receiving traditional HD. Mean +/- SEM triglyceride level was 1.62 +/- 0.15 mmol/L (143.3 +/- 13.6 mg/dL) in high-flux dialysis patients, 2.39 +/- 0.27 mmol/L (211.6 +/- 24.1 mg/dL) in conventional dialysis patients, and 1.55 +/- 0.13 mmol/L (137.1 +/- 11.5 mg/dL) in normal age- and sex-matched controls. In addition, we found that in patients undergoing high-flux HD, females had higher high-density lipoprotein2 (HDL2) levels (0.62 +/- 0.03 mmol/L [23.8 +/- 1.3 mg/dL]) than males (0.33 +/- 0.04 mmol/L [12.9 +/- 1.7 mg/dL]) (P < 0.01). The mechanism(s) responsible for divergent lipid profiles in subsets of HD patients deserves further investigation. Whether reductions of hypertriglyceridemia and/or increases of HDL2 will diminish the incidence of cardiovascular disease in dialysis patients is unknown.


Calcium mass transfer with dialysate containing 1.25 and 1.75 mmol/L calcium in peritoneal dialysis patients. Studies with 1.75 mmol/L calcium dialysate have shown that patients gain calcium from dialysate. Thus, hypercalcemia, especially when calcium compounds are used for phosphate control, is a commonly seen complication. Dialysate with 1.25 mmol/L calcium has been available since 1989. Little is known about calcium mass transfer (CMT) with dialysate of this calcium concentration. CMT was measured in 20 stable adult peritoneal dialysis patients. Each CMT study consisted of a 2-L continuous ambulatory peritoneal dialysis (CAPD) exchange with a dwell time of 4 hours. CMT studies were performed using 1.25 and 1.75 mmol/L calcium dialysate with 1.5, 2.5, and 4.25 g/dL dextrose concentrations. CMT with 1.25 mmol/L calcium dialysate was compared to that with 1.75 mmol/L for each dextrose concentration. With a dextrose concentration of 1.5 g/dL, the mean CMT for 1.25 mmol/L calcium dialysate was -0.1 +/- 0.3 mmol versus 0.6 +/- 0.3 mmol for 1.75 mmol/L calcium dialysate (P < 0.0001). A dextrose concentration of 2.5 g/dL resulted in a mean CMT of -0.4 +/- 0.2 mmol for 1.25 mmol/L calcium versus 0.45 +/- 0.25 mmol for 1.75 mmol/L calcium (P < 0.0001). Using a dextrose concentration of 4.25 g/dL, the mean CMT was -0.7 +/- 0.25 mmol for 1.25 mmol/L calcium versus -0.05 +/- 0.35 mmol for 1.75 mmol/L calcium (P < 0.0001). Mean serum ionized calcium (SiCa) was between 1.15 and 1.20 mmol/L for all study groups. CMT inversely correlated with SiCa for each type of dialysate used. CMT was dependent on the concentrations of calcium and dextrose in the dialysate and the SiCa level at the time of the exchange.(ABSTRACT TRUNCATED AT 250 WORDS)


Specific opsonic activity for staphylococci in peritoneal dialysis effluent during continuous ambulatory peritoneal dialysis. In a prospective study of intraperitoneal opsonins in 30 patients undergoing continuous ambulatory peritoneal dialysis (CAPD), the IgG concentration, the fibronectin concentration, the specific antistaphylococcal antibody level, and the opsonic activity against Staphylococcus epidermidis were measured in peritoneal dialysis effluent from the initiation of CAPD and monthly for 6 months. Significant correlation was found between the four assays, but the interindividual and intraindividual variations were considerable. No statistically significant correlation was observed between susceptibility of the patients to CAPD-related infectious peritonitis and any of the above-mentioned parameters of humoral defense. We conclude that at the present time it is not feasible to use these assays for the establishment of prognosis with regard to peritonitis in CAPD.


Survival differences among older dialysis patients in the southeast. Older end-stage renal disease (ESRD) patients treated by chronic dialysis have higher mortality in the United States than in many other countries. While increasing age, white race, male sex, and/or diabetes are considered risk factors for survival, few studies of older dialysis patients have simultaneously considered multiple predictor variables and their interactions. Using information contained in the 1982 to 1986 ESRD Network 20 database for Georgia and South Carolina, we studied hospitalizations and survival of 1,354 blacks and 965 whites who were age 60 years or older when they began dialysis therapy. Survival time was modeled using the Cox life-table regression method. Older blacks' median age at dialysis initiation was 67.4, compared with 68.7 for older whites (P = 0.001). Blacks were more likely than whites (P < 0.001) to have hypertension-related or diabetes-related ESRD. White patients experienced approximately 25% more hospitalization when adjustment was made for patient-days at risk. Separate multivariate survival models were required for patients with diabetes-related versus non-diabetes-related ESRD. Among diabetics, mortality was higher among whites and among patients who were older when they began dialysis. Among patients with non-diabetes-related ESRD, mortality was higher among patients who were older when they began dialysis, but the age effect was much stronger for white males. Our hospitalization and mortality data support the view that unmeasured severity (or frailty) differences characterize white as compared with black dialysis patients. Among non-diabetes-related ESRD patients, the age effect on survival was more severe in white males than in blacks or in white females. The high mortality we observed among older dialysis patients in Georgia and South Carolina warrants further study; the data may in part reflect patients' lower socioeconomic status compared with age, race, and sex-matched controls.


Acute tubular necrosis associated with Lowe's syndrome: possible role of rhabdomyolysis. The oculo-cerebral-renal syndrome of Lowe is an X-linked recessive disorder characterized by severe mental retardation, congenital cataracts, renal tubular dysfunction, growth retardation, hypotonia, glaucoma, and rickets. Recently, it has been found that serum concentrations of the muscle enzymes are elevated, providing evidence that there is primary muscle involvement in this disorder. The renal functional abnormalities that occur have also been further delineated. Renal tubular dysfunction presents within the first year of life, followed by a serum creatinine level that increases with age. Renal failure generally occurs in the fourth decade of life. We report two patients with Lowe's syndrome who presented with new onset of acute renal failure (ARF). Workup of their ARF established the diagnosis of acute tubular necrosis with evidence of rhabdomyolysis in one case. These patients were treated aggressively with dialysis and had subsequent recovery of renal function to their baseline state. We suggest that patients with Lowe's syndrome who present with an acute change in their renal function should be treated early with vigorous hydration therapy. If dialysis is indicated, it should be initiated. Furthermore, these patients should be promptly evaluated for evidence of rhabdomyolysis with alkalinization of the urine if possible.


Henoch-Schönlein vasculitis as a manifestation of IgA-associated disease in cirrhosis. Cirrhosis has been associated with a variety of glomerular lesions that generally include deposits of IgA in the mesangium. However, loss of renal function secondary to IgA deposition in cirrhotics is infrequent. An unusual patient who developed rapidly progressive glomerulonephritis followed by leukocytoclastic vasculitis with IgA deposition on skin biopsy is presented. We postulate that this is an example of Henoch-Schönlein purpura occurring secondary to altered IgA processing in cirrhosis.


Pregnancy in patients on chronic ambulatory peritoneal dialysis. Both conception and successful completion of pregnancy are rare occurrences in female patients on chronic renal replacement therapy. Only a handful of successful pregnancies and deliveries have been reported in patients receiving hemodialysis (HD). Even less common are reports of successful pregnancy and delivery in patients receiving chronic ambulatory peritoneal dialysis (CAPD). Among the more common causes of fetal loss are abruptio placentae and other causes of spontaneous miscarriage. We report here three cases of pregnancy in patients on CAPD; two of these pregnancies progressed successfully to spontaneous delivery, while the third terminated during an episode of acute peritonitis. Furthermore, we have reviewed the literature concerning the outcome of pregnancy in the dialysis population on CAPD.


The pathogenesis of hyperacute xenograft rejection. A critical shortage of donor organs has driven many in the transplantation community to consider the use of animals as organ donors for humans, that is, xenotransplantation. While successful xenotransplantation of primate kidneys was achieved 25 years ago, most now advocate use of nonprimates as donors because of the risk of disease transmission and ethical concerns attendant to the use of primates. The major hurdle to xenotransplantation of organs between phylogenetically disparate species is the hyperacute rejection reaction that invariably destroys organ xenografts placed in unmodified recipients. Here we review recent insights concerning the pathogenesis of hyperacute rejection reactions. We focus particular attention on the endothelial cell, which serves not only as the target of xenoreactive antibodies and complement, but also, as a consequence of endothelial cell activation, as an instrument of tissue injury. We discuss a phenomenon called "accommodation" in which an organ graft acquires resistance to humoral-mediated injury.


Genotype-phenotype relationships in human red/green color-vision defects: molecular and psychophysical studies. The relationship between the molecular structure of the X-linked red and green visual pigment genes and color-vision phenotype as ascertained by anomaloscopy was studied in 64 color-defective males. The great majority of red-green defects were associated with either the deletion of the green-pigment gene or the formation of 5' red-green hybrid genes or 5' green-red hybrid genes. A rapid PCR-based method allowed detection of hybrid genes, including those undetectable by Southern blot analysis, as well as more precise localization of the fusion points in hybrid genes. Protan color-vision defects appeared always associated with 5' red-green hybrid genes. Carriers of single red-green hybrid genes with fusion in introns 1-4 were protanopes. However, carriers of hybrid genes with red-green fusions in introns 2, 3, or 4 in the presence of additional normal green genes manifested as either protanopes or protanomalous trichromats, with the majority being protanomalous. Deutan defects were associated with green-pigment gene deletions, with 5' green-red hybrid genes, or, rarely, with 5' green-red-green hybrid genes. Complete green-pigment gene deletions or green-red fusions in intron 1 were usually associated with deuteranopia, although we unexpectedly found three carriers of a single red-pigment gene without any green-pigment genes to be deuteranomalous trichromats. All but one of the other deuteranomalous subjects had green-red hybrid genes with intron 1, 2, 3, or 4 fusions, as well as several normal green-pigment genes. The one exception had a grossly normal gene array, presumably with a more subtle mutation. Amino acid differences in exon 5 largely determine whether a hybrid gene will be more redlike or more greenlike in phenotype. Various discrepancies as to severity (dichromacy or trichromacy) remain unexplained but may arise because of variability of expression, postreceptoral variation, or both. When phenotypic color-vision defects exist, the kind of defect (protan or deutan) can be predicted by molecular analysis. Red-green hybrid genes are probably always associated with protan color-vision defects, while the presence of green-red hybrid genes may not always manifest phenotypically with color-vision defects. Four subjects who were found to have 5' green-red hybrid genes in addition to normal red- and green-pigment genes had normal color vision as determined by anomaloscopy. These were discovered among a group of 129 Caucasian males who had been recruited as volunteers for a vision study.(ABSTRACT TRUNCATED AT 400 WORDS)


Evidence for genetic heterogeneity in tuberous sclerosis: one locus on chromosome 9 and at least one locus elsewhere. Linkage of tuberous sclerosis complex (TSC), an autosomal dominant disorder, to markers on chromosome 9 was reported first in 1987. This assignment was confirmed by an international collaborative study that suggested more than one locus may be responsible for the phenotype. We studied 14 multigenerational TSC families (13 previously unreported) with markers for nine loci in the linked region of chromosome 9q32-q34. Our results confirm the previous reports that the genetic locus in one-third to one-half of families maps to chromosome 9. Comparison of clinical findings in the chromosome 9-linked families with those in the chromosome 9-unlinked families reveals only a higher incidence of ungual fibromata in the chromosome 9-linked families.


Fluorescent multiplex linkage analysis and carrier detection for Duchenne/Becker muscular dystrophy. We have developed a fast and accurate PCR-based linkage and carrier detection protocol for families of Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD) patients with or without detectable deletions of the dystrophin gene, using fluorescent PCR products analyzed on an automated sequencer. When a deletion is found in the affected male DMD/BMD patient by standard multiplex PCR, fluorescently labeled primers specific for the deleted and nondeleted exon(s) are used to amplify the DNA of at-risk female relatives by using multiplex PCR at low cycle number (20 cycles). The products are then quantitatively analyzed on an automatic sequencer to determine whether they are heterozygous for the deletion and thus are carriers. As a confirmation of the deletion data, and in cases in which a deletion is not found in the proband, fluorescent multiplex PCR linkage is done by using four previously described polymorphic dinucleotide sequences. The four (CA)n repeats are located throughout the dystrophin gene, making the analysis highly informative and accurate. We present the successful application of this protocol in families who proved refractory to more traditional analyses.


Significant linkage disequilibrium between the Huntington disease gene and the loci D4S10 and D4S95 in the Dutch population. Significant linkage disequilibrium has been found between the Huntington disease (HD) gene and DNA markers located around D4S95 and D4S98. The linkage-disequilibrium studies favor the proximal location of the HD gene, in contrast to the conflicting results of recombination analyses. We have analyzed 45 Dutch HD families with 19 DNA markers and have calculated the strength of linkage disequilibrium. Highly significant linkage disequilibrium has been detected with D4S95, consistent with the studies in other populations. In contrast with most other studies, however, the area of linkage disequilibrium extends from D4S10 proximally to D4S95, covering 1,100 kb. These results confirm that the HD gene most likely maps near D4S95.


Evidence against an X-linked locus close to DXS7 determining visual loss susceptibility in British and Italian families with Leber hereditary optic neuropathy. Leber hereditary optic neuropathy (LHON) is associated with mutations of mtDNA, but two features of LHON pedigrees are not explicable solely on the basis of mitochondrial inheritance. There is a large excess of affected males, and not all males at risk develop the disease. These observations could be explained by the existence of an X-linked visual loss susceptibility gene. This hypothesis was supported by linkage studies in Finland, placing the susceptibility locus at DXS7, with a maximum lod score of 2.48 at a recombination fraction of 0. Linkage studies in 1 Italian and 12 British families with LHON, analyzed either together or separately depending on the associated mtDNA mutation, have excluded the presence of such a locus from an interval of about 30 cM around DXS7 in these kindreds, with a total lod score of -26.51 at a recombination fraction of 0.


The autosomal dominant familial exudative vitreoretinopathy locus maps on 11q and is closely linked to D11S533. Autosomal dominant familial exudative vitreoretinopathy (adFEVR) is a hereditary disorder characterized by the incomplete vascularization of the peripheral retina. The primary biochemical defect in adFEVR is unknown. The adFEVR locus has tentatively been assigned to 11q by linkage studies. We report the results of an extended multipoint linkage analysis of two families with adFEVR by using five markers (INT2, D11S533, D11S527, D11S35, and CD3D) from 11q13-q23. Pairwise linkage data obtained in the two families were rather similar and hence have not provided evidence for genetic heterogeneity. The highest complied two-point lod score (3.67, at a recombination fraction of .07) was obtained for the disease locus versus D11S533. Multipoint analyses showed that the adFEVR locus maps most likely, with a maximum location score of over 20, between D11S533/D11S527 and D11S35, at recombination rates of .147 and .104, respectively. Close linkage without recombination (maximum lod score 11.26) has been found between D11S533 and D11S527.


Power of sib-pair and sib-trio linkage analysis with assortative mating and multiple disease loci. Sib-pair linkage analysis has been proposed for identifying genes that predispose to common diseases. We have shown that the presence of assortative mating and multiple disease-susceptibility loci (genetic heterogeneity) can increase the required sample size for affected-affected sib pairs several fold over the sample size required under random mating. We propose a new test statistic based on sib trios composed of either one unaffected and two affected siblings or one affected and two unaffected siblings. The sample-size requirements under assortative mating and multiple disease loci for these sib-trio statistics are much smaller, under most conditions, than the corresponding sample sizes for sib pairs. Study designs based on data from sib trios with one or two affected members are recommended whenever assortative mating and genetic heterogeneity are suspected.


A double mutation in exon 6 of the beta-hexosaminidase alpha subunit in a patient with the B1 variant of Tay-Sachs disease. The B1 variant form of Tay-Sachs disease is enzymologically unique in that the causative mutation(s) appear to affect the active site in the alpha subunit of beta-hexosaminidase A without altering its ability to associate with the beta subunit. Most previously reported B1 variant mutations were found in exon 5 within codon 178. The coding sequence of the alpha subunit gene of a patient with the B1 variant form was examined with a combination of reverse transcription of mRNA to cDNA, PCR, and dideoxy sequencing. A double mutation in exon 6 has been identified: a G574----C transversion causing a val192----leu change and a G598----A transition resulting in a val200----met alteration. The amplified cDNAs were otherwise normal throughout their sequence. The 574 and 598 alterations have been confirmed by amplification directly from genomic DNA from the patient and her mother. Transient-expression studies of the two exon 6 mutations (singly or together) in COS-1 cells show that the G574----C change is sufficient to cause the loss of enzyme activity. The biochemical phenotype of the 574 alteration in transfection studies is consistent with that expected for a B1 variant mutation. As such, this mutation differs from previously reported B1 variant mutations, all of which occur in exon 5.


Gaucher disease: A G+1----A+1 IVS2 splice donor site mutation causing exon 2 skipping in the acid beta-glucosidase mRNA. Gaucher disease is the most frequent lysosomal storage disease and the most prevalent Jewish genetic disease. About 30 identified missense mutations are causal to the defective activity of acid beta-glucosidase in this disease. cDNAs were characterized from a moderately affected 9-year-old Ashkenazi Jewish Gaucher disease type 1 patient whose 80-year-old, enzyme-deficient, 1226G (Asn370----Ser [N370S]) homozygous grandfather was nearly asymptomatic. Sequence analyses revealed four populations of cDNAs with either the 1226G mutation, an exact exon 2 (delta EX2) deletion, a deletion of exon 2 and the first 115 bp of exon 3 (delta EX2-3), or a completely normal sequence. About 50% of the cDNAs were the delta EX2, the delta EX2-3, and the normal cDNAs, in a ratio of 6:3:1. Specific amplification and characterization of exon 2 and 5' and 3' intronic flanking sequences from the structural gene demonstrated clones with either the normal sequence or with a G+1----A+1 transition at the exon 2/intron 2 boundary. This mutation destroyed the splice donor consensus site (U1 binding site) for mRNA processing. This transition also was present at the corresponding exon/intron boundary of the highly homologous pseudogene. This new mutation, termed "IVS2 G+1----A+1," is the first splicing mutation described in Gaucher disease and accounted for about 3.4% of the Gaucher disease alleles in the Ashkenazi Jewish population. The occurrence of this "pseudogene"-type mutation in the structural gene indicates the role of acid beta-glucosidase pseudogene and structural gene rearrangements in the pathogenesis of this disease.


Identification of two different point mutations associated with the fluoride-resistant phenotype for human butyrylcholinesterase. The fluoride variant of human butyrylcholinesterase owes its name to the observation that it is resistant to inhibition by 0.050 mM sodium fluoride in the in vitro assay. Individuals who are heterozygous for the fluoride and atypical alleles experience about 30 min of apnea, rather than the usual 3-5 min, after receiving succinyldicholine. Earlier we reported that the atypical variant has a nucleotide substitution which changes Asp 70 to Gly. In the present work we have identified two different point mutations associated with the fluoride-resistant phenotype. Fluoride-1 has a nucleotide substitution which changes Thr 243 to Met (ACG to ATG). Fluoride-2 has a substitution which changes Gly 390 to Val (GGT to GTT). These results were obtained by DNA sequence analysis of the butyrylcholinesterase gene after amplification by PCR. The subjects for these analyses were 4 patients and 21 family members.


Lipoprotein(a) in women twins: heritability and relationship to apolipoprotein(a) phenotypes. Lp(a) is a unique lipoprotein consisting of an LDL-like particle and a characteristic protein, apo(a). Increased levels of Lp(a) constitute a risk factor for coronary heart disease. Variation in the size of the apo(a) protein is a phenotype controlled by the apo(a) gene on chromosome 6 and is related to Lp(a) plasma levels. Based on 169 MZ and 125 DZ adult female twin pairs, this study's purpose was to estimate the proportion of the variation in Lp(a) levels that is due to genetic influences and to determine the extent to which the apo(a) locus explains this heritability. Lp(a) levels were significantly more similar in MZ twins than in DZ twins: mean co-twin differences were 3.9 +/- 5.7 mg/dl and 16.0 +/- 19.9 mg/dl (P less than .001), respectively. Intraclass correlations were .94 in MZ twins and .32 in DZ twins, resulting in a heritability estimate of .94 (P less than .001). Heritability was then calculated using only co-twins with the same apo(a) phenotype: the heritability estimate decreased to .45 but was still highly significant (P less than .001). Therefore, on the basis of heritability analysis of women twins, Lp(a) levels are almost entirely genetically controlled. Variation at the apo(a) locus contributes to this heritability, although other genetic factors could be involved.


Nonsense mutations of the von Willebrand factor gene in patients with von Willebrand disease type III and type I. von Willebrand disease (vWD) is the most common inherited bleeding disorder in humans. The disease is caused by qualitative and quantitative abnormalities of the von Willebrand factor (vWF). Genomic DNA from 25 patients with vWD type III, the most severe form of the disease, was studied using PCR followed by restriction-enzyme analysis and direct sequencing of the products. Nonsense mutations (CGA----TGA) were detected in exons 28, 32, and 45 by screening of all the 11 CGA arginine codons of the vWF gene. Two patients were found to be homozygous and five heterozygous for the mutation. Both parents and some of the relatives of the homozygous patients carry the mutation. These are the first reported examples of homozygous point mutations associated with the severe form of vWD. In the three heterozygous probands, one of the parents carried the mutation and had vWD type I. Family studies including parents and family members with or without vWD type I indicated that these three heterozygous patients are likely to be compound heterozygous. Twenty-one individuals from these seven families with vWD type I were found to be heterozygous for the mutation.


Inter- and intrafamilial heterogeneity: effective sampling strategies and comparison of analysis methods. Heterogeneity, both inter- and intrafamilial, represents a serious problem in linkage studies of common complex diseases. In this study we simulated different scenarios with families who phenotypically have identical diseases but who genotypically have two different forms of the disease (both forms genetic). We examined the proportion of families displaying intrafamilial heterogeneity, as a function of mode of inheritance, gene frequency, penetrance, and sampling strategies. Furthermore, we compared two different ways of analyzing linkage in these data sets: a two-locus (2L) analysis versus a one-locus (SL) analysis combined with an admixture test. Data were simulated with tight linkage between one disease locus and a marker locus; the other disease locus was not linked to a marker. Our findings are as follows: (1) In contrast to what has been proposed elsewhere to minimize heterogeneity, sampling only "high-density" pedigrees will increase the proportion of families with intrafamilial heterogeneity, especially when the two forms are relatively close in frequency. (2) When one form is dominant and one is recessive, this sampling strategy will greatly decrease the proportions of families with a recessive form and may therefore make it more difficult to detect linkage to the recessive form. (3) An SL analysis combined with an admixture test achieves about the same lod scores and estimate of the recombination fraction as does a 2L analysis. Also, a 2L analysis of a sample of families with intrafamilial heterogeneity does not perform significantly better than an SL analysis. (4) Bilineal pedigrees have little effect on the mean maximum lod score and mean maximum recombination fraction, and therefore there is little danger that including these families will lead to a false exclusion of linkage.


The tyrosinase-positive oculocutaneous albinism locus maps to chromosome 15q11.2-q12. Tyrosinase-positive oculocutaneous albinism (ty-pos OCA), an autosomal recessive disorder of the melanin biosynthetic pathway, is the most common type of albinism occurring worldwide. In southern African Bantu-speaking negroids it has an overall prevalence of about 1/3,900. Since the basic biochemical defect is unknown, a linkage study with candidate loci, candidate chromosomal regions, and random loci was undertaken. The ty-pos OCA locus was found to be linked to two arbitrary loci, D15S10 and D15S13, in the Prader-Willi/Angelman chromosomal region on chromosome 15q11.2-q12. The pink-eyed dilute locus, p, on mouse chromosome 7, maps close to a region of homology on human chromosome 15q, and we postulate that the ty-pos OCA and p loci are homologous.


Genethics: project accountability via evaluation of teacher and student growth. Accountability through demonstrated learning is increasingly being demanded by agencies funding science education projects. For example, the National Science Foundation requires evidence of the educational impact of programs designed to increase the scientific understanding and competencies of teachers and their students. The purpose of this paper is to share our human genetics educational experiences and accountability model with colleagues interested in serving the genetics educational needs of in-service secondary school science teachers and their students. Our accountability model is facilitated through (1) identifying the educational needs of the population of teachers to be served, (2) articulating goals and measurable objectives to meet these needs, and (3) then designing and implementing pretest/posttest questions to measure whether the objectives have been achieved. Comparison of entry and exit levels of performance on a 50-item test showed that teacher-participants learned a statistically significant amount of genetics content in our NSF-funded workshops. Teachers, in turn, administered a 25-item pretest/posttest to their secondary school students, and collective data from 121 classrooms across the United States revealed statistically significant increases in student knowledge of genetics content. Methods describing our attempts to evaluate teachers' use of pedagogical techniques and bioethical decision-making skills are briefly addressed.


A problem-based learning approach to teaching medical genetics. A newly developed problem-based medical genetics course that was integrated into the fourth-year medical school curriculum of the University of Texas Health Science Center at San Antonio is described. To provide a basic genetic background for the clinical rotations, a supplemental computer tutorial is required during the second year. These two formats prepare the medical students to recognize genetic diseases, to provide basic genetic counseling in their daily practice, and to appropriately refer patients to genetic specialists.


DNA polymorphism analysis in families with recurrence of free trisomy 21. We used DNA polymorphic markers on the long arm of human chromosome 21 in order to determine the parental and meiotic origin of the extra chromosome 21 in families with recurrent free trisomy 21. A total of 22 families were studied, 13 in which the individuals with trisomy 21 were siblings (category 1), four families in which the individuals with trisomy 21 were second-degree relatives (category 2), and five families in which the individuals with trisomy 21 were third-degree relatives, that is, their parents were siblings (category 3). In five category 1 families, parental mosaicism was detected, while in the remaining eight families, the origin of nondisjunction was maternal. In two of the four families of category 2 the nondisjunctions originated in individuals who were related. In only one of five category 3 families, the nondisjunctions originated in related individuals. These results suggest that parental mosaicism is an important etiologic factor in recurrent free trisomy 21 (5 of 22 families) and that chance alone can explain the recurrent trisomy 21 in many of the remaining families (14 of 22 families). However, in a small number of families (3 of 22), a familial predisposing factor or undetected mosaicism cannot be excluded.


Localization of the photoreceptor gene ROM1 to human chromosome 11 and mouse chromosome 19: sublocalization to human 11q13 between PGA and PYGM. Rom-1 is a retinal integral membrane protein that, together with the product of the human retinal degeneration slow gene (RDS), defines a photoreceptor-specific protein family. The gene for rom-1 (HGM symbol: ROM1) has been assigned to human chromosome 11 and mouse chromosome 19 by Southern blot analysis of somatic cell hybrid DNAs. ROM1 was regionally sublocalized to human 11p13-11q13 by using three mouse-human somatic cell hybrids; in situ hybridization refined the sublocalization to human 11q13. Analysis of somatic cell hybrids suggested that the most likely localization of ROM1 is in the approximately 2-cM interval between human PGA (human pepsinogen A) and PYGM (muscle glycogen phosphorylase). ROM1 appears to be a new member of a conserved syntenic group whose members include such genes as CD5, CD20, and OSBP (oxysterol-binding protein), on human chromosome 11 and mouse chromosome 19. Localization of the ROM1 gene will permit the examination of its linkage to hereditary retinopathies in man and mouse.


Genetic determination of high-density lipoprotein-cholesterol and apolipoprotein A-1 plasma levels in a family study of cardiac catheterization patients. Plasma levels of two lipoprotein risk factors, high-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A-1 (apo A-1), have been shown to be negatively associated with the risk of developing coronary artery disease, and several reports have examined familial factors in HDL-C and apo A-1 levels. A number of studies suggest that shared genes influence familial resemblance of these lipoprotein levels far more than do shared environments. Possible mechanisms for the inheritance of these two risk factors (HDL-C and apo A-1 plasma levels) are explored using data from 390 individuals in 69 families ascertained through probands undergoing diagnostic cardiac catheterization. Segregation analysis was used to test a series of specific models of inheritance. Evidence for single-locus control of apo A-1 levels, with Mendelian transmission of a dominant allele leading to elevated apo A-1 levels, was seen in these families, although there was additional correlation among sibs present. This locus accounted for 48.6% and 37.2% of the total variation in apo A-1 levels in males and females, respectively. Similar evidence of segregation at a single locus controlling HDL-C levels was not seen in these families.


Structure and chromosomal localization of the human antidiuretic hormone receptor gene. Applying a genomic DNA-expression approach, we cloned the gene and cDNA coding for the human anti-diuretic hormone receptor, also called "vasopressin V2 receptor" (V2R). The nucleotide sequence of both cloned DNAs provided the information to elucidate the structure of the isolated transcriptional unit. The structure of this gene is unusual in that it is the first G protein-coupled receptor gene that contains two very small intervening sequences, the second of which separates the region encoding the seventh transmembrane region from the rest of the open reading frame. The sequence information was used to synthesize appropriate oligonucleotides to be used as primers in the PCR. The V2R gene was localized by PCR using DNA from hybrid cells as template. The gene was found to reside in the q28-qter portion of the human X chromosome, a region identified as the locus for congenital nephrogenic diabetes insipidus.


Testing Hardy-Weinberg equilibrium on allelic data from VNTR loci. Several methods for testing independence of pairs of alleles in a population that are obtained from a VNTR locus are presented. We assume an exchangeable quasi-continuous distribution of the fragment lengths used to measure the allelic pairs. Bivariate-estimated quantiles computed from the quantiles of the entire data set are then utilized for testing independence. These methods have the advantage of being minimally susceptible to the criticism of (a) the inability of a technology to measure a few small-sized or rather large-sized fragments and (b) inadequate estimation of the homozygotic proportion.


A Monte Carlo method for combined segregation and linkage analysis. We introduce a Monte Carlo approach to combined segregation and linkage analysis of a quantitative trait observed in an extended pedigree. In conjunction with the Monte Carlo method of likelihood-ratio evaluation proposed by Thompson and Guo, the method provides for estimation and hypothesis testing. The greatest attraction of this approach is its ability to handle complex genetic models and large pedigrees. Two examples illustrate the practicality of the method. One is of simulated data on a large pedigree; the other is a reanalysis of published data previously analyzed by other methods.


Cytochrome b558-negative, autosomal recessive chronic granulomatous disease: two new mutations in the cytochrome b558 light chain of the NADPH oxidase (p22-phox). Chronic granulomatous disease (CGD) is characterized by the failure of activated phagocytes to generate superoxide. Defects in at least four different genes lead to CGD. Patients with the X-linked form of CGD have mutations in the gene for the beta-subunit of cytochrome b558 (gp91-phox). Patients with a rare autosomal recessive form of CGD have mutations in the gene for the alpha-subunit of this cytochrome (p22-phox). Usually, this leads to the absence of cytochrome b558 in the phagocytes (A22(0) CGD). We studied the molecular defect in five European patients from three unrelated families with this type of CGD. P22-phox mRNA was reverse-transcribed, and the coding region was amplified by PCR in one fragment and sequenced. Three patients from one family, with parents that were first cousins, were homozygous for a single base substitution (G-297-->A) resulting in a nonconservative amino acid change (Arg-90-->Gln). This mutation was previously found in a compound heterozygote A22(0) CGD patient. Another patient, also from first-cousin parents, was homozygous for an A-309-->G mutation in the open reading frame that predicts a nonconservative amino acid replacement (His-94-->Arg). The fifth patient was also born from a first-cousin marriage and was shown to be homozygous for the absence of exon 4 from the cDNA. In this patient, a G-->A substitution was found at position 1 of intron 4 in the genomic DNA. Therefore, the absence of exon 4 in the cDNA of this patient is due to a splicing error.(ABSTRACT TRUNCATED AT 250 WORDS)


X-linked alpha-thalassemia/mental retardation (ATR-X) syndrome: localization to Xq12-q21.31 by X inactivation and linkage analysis. We have examined seven pedigrees that include individuals with a recently described X-linked form of severe mental retardation associated with alpha-thalassemia (ATR-X syndrome). Using hematologic and molecular approaches, we have shown that intellectually normal female carriers of this syndrome may be identified by the presence of rare cells containing HbH inclusions in their peripheral blood and by an extremely skewed pattern of X inactivation seen in cells from a variety of tissues. Linkage analysis has localized the ATR-X locus to an interval of approximately 11 cM between the loci DXS106 and DXYS1X (Xq12-q21.31), with a peak LOD score of 5.4 (recombination fraction of 0) at DXS72. These findings provide the basis for genetic counseling, assessment of carrier risk, and prenatal diagnosis of the ATR-X syndrome. Furthermore, they represent an important step in developing strategies to understand how the mutant ATR-X allele causes mental handicap, dysmorphism, and down-regulation of the alpha-globin genes.


Different mosaicism frequencies for proximal and distal Duchenne muscular dystrophy (DMD) mutations indicate difference in etiology and recurrence risk. In about 65% of the cases of Duchenne muscular dystrophy (DMD) a partial gene deletion or duplication in the dystrophin gene can be detected. These mutations are clustered at two hot spots: 30% at the hot spot in the proximal part of the gene and about 70% at a more distal hot spot. Unexpectedly we observed a higher frequency of proximal gene rearrangements among proved "germ line" mosaic cases. Of the 24 mosaic cases we are aware of, 19 (79%) have a proximal mutation, while only 5 (21%) have a distal mutation. This finding indicates that the mutations at the two hot spots in the dystrophin gene differ in origin. Independent support for the different mosaicism frequency was found by comparing the mutation spectra observed in isolated cases of DMD and familial cases of DMD. In a large two-center study of 473 patients from Brazil and the Netherlands, we detected a significant difference in the deletion distribution of isolated (proximal:distal ratio 1:3) and familial cases (ratio 1:1). We conclude from these data that proximal deletions most likely occur early in embryonic development, causing them to have a higher chance of becoming familial, while distal deletions occur later and have a higher chance of causing only isolated cases. Finally, our findings have important consequences for the calculation of recurrence-risk estimates according to the site of the deletion: a "proximal" new mutant has an increased recurrence risk of approximately 30%, and a "distal" new mutant has a decreased recurrence risk of approximately 4%.


A cooperative binomial ascertainment model. It has been shown that the classical binomial form of ascertainment, assuming a constant probability pi that any affected individual may become a proband for his pedigree, cannot describe a rather wide range of ascertainment procedures that might arise in practice. Some more general heuristic ascertainment formulas might then be preferred, and in this paper we consider the probabilistic basis for these formulas. We retain the binomial assumption of the classical scheme but allow the ascertainment probability to depend on the number of potential probands per pedigree. This probability can be expressed by an increasing or a decreasing function of that number. Various illustrations are given and situations where the "cooperative" binomial scheme should be valuable are discussed.


A prospective cytogenetic study of 36 cases of DiGeorge syndrome. Cytogenetic analysis was carried out in a prospective series of 36 children with DiGeorge syndrome. High-resolution banding (> 850 bands/haploid set) was achieved in 30 cases. Monosomy 22q11.21-->q11.23 was found in 9 of these 30 cases. In each of these cases monosomy 22q11.21-->q11.23 resulted from an interstitial deletion and not from a translocation. No other chromosome abnormalities were seen.