Cation transport in lymphoblastoid cell lines established from bipolar manic-depressive patients

Lymphoblastoid cell lines established from patients suffering from bipolar manic depression have been used to study the possible involvement of cation transport in the aetiology of this illness. No significant difference was found in the K+ fluxes mediated by the ouabain-sensitive sodium pump, the diuretic-sensitive cotransport system and the passive leak pathway of cell lines established from either control or bipolar subjects. The mean value for the specific binding of 3H-ouabain (sodium pump site number) was significantly higher in the bipolar group (approximately 30%) than in the control group.

Quantitative margin analysis in the scanning electron microscope

Interface between restorative materials and tooth hard substances must be morphologically as perfect as possible to avoid plaque accumulation and subsequent secondary caries or pulpal diseases. Therefore the marginal behavior of restorations is an important parameter to predict their longevity. Morphologically, the quality of margins is characterized by different well defined criteria. Using a replica technique it is possible to assess the complete marginal circumference of restorations in the SEM. Margins of restorations show a large variety of their morphology. This publication describes a method to quantify the quality of dental restorations. The restoration margins are traced on the SEM screen with a digitizer and an interface to measure the margin's length. Simultaneously the margin quality is assessed and assigned to the corresponding lengths. The % distribution of the quality criteria for each restoration is then calculated. Using a comparative light microscope, the replicas are aligned and mounted identically in the SEM for longitudinal studies. The results presented are limited to tests for the accuracy of the method. Using 5 criteria to characterize the margin quality, it was found that the difference between two measurements by the same operator, 4 weeks apart was 3% +/- 2.6%. The largest difference for one group was 9%. In another accuracy test where 4 criteria for margin characterization were used, the difference between two measurements was 1.9% +/- 0.9%. The largest difference between two groups found was 3.4%. This method can be used for longitudinal studies in vivo, but also for in vitro screening tests with new materials.

NIMH Collaborative Program on the Psychobiology of Depression: clinical

As part of the National Institute of Mental Health Collaborative Program of Depression study, data were collected on 2,225 first-degree relatives of 612 probands. A subset consisting of 187 families of bipolar patients was made available to participants of Genetic Analysis Workshop 5 (GAW5). A description of these data, including sample sizes, diagnoses, and a summary of published analyses, is given.

Schizophrenia and the question of genetic heterogeneity

Despite major advances in psychiatric diagnosis during the past 20 years, boundaries of the schizophrenic syndrome remain elusive. Moreover, in pedigrees containing cases of schizophrenia there are marked between-pedigree differences with respect to prognosis, familial patterns of psychiatric illness, drug response, and especially association of affected status with a specific chromosomal locus. Such between-pedigree differences suggest the syndrome may be made up of several different diseases. Linkage of affected status to specific loci may aid in resolving genetic heterogeneity. Large multigenerational informative pedigrees may permit the separation into those that do and do not link to a genomic locus of interest. Admixture analysis of smaller informative pedigrees may permit separation of linked and unlinked pedigrees on the basis of differences in the recombination fraction. Finally, biological "markers" can be used before the genetic analysis to separate putative linked and unlinked pedigrees. The combined study of genetic linkage and clinical heterogeneity will aid in the resolution of etiological heterogeneity of schizophrenia and the delineation of meaningful diagnostic boundaries.

Segregation and linkage analyses of bipolar and major depressive illnesses in multigenerational pedigrees

Data were collected on six large multigenerational pedigrees, four ascertained through a proband with major depression and two ascertained through a proband with a bipolar form of illness. Diagnoses were made using the SADS-L structured interview and Research Diagnostic Criteria (RDC). Complex segregation analyses were conducted on the bipolar and the major depression pedigree sets using a model allowing for both major locus and polygenic inheritance; in these analyses a variety of diagnostic schemes and assumptions concerning the lifetime population prevalence were examined. Linkage analyses on standard markers were conducted using parameters for transmission of susceptibility to illness derived from the segregation analyses. Results of the segregation analyses were quite sensitive to the diagnostic and prevalence assumptions. In the pedigrees ascertained through probands with a bipolar form of illness, we were unable to discriminate between major gene and polygenic inheritance. The data were compatible with Mendelian major gene transmission of susceptibility to illness when bipolar and schizoaffective manic diagnoses were considered as affected and the lifetime population prevalence was between 0.04 and 0.06. Outside this narrow prevalence range, or when additional diagnoses, such as major depression or hypomania, were included as expressions of liability to disease, major gene transmission of susceptibility to disease could be rejected. Similarly, in the pedigrees ascertained through probands with major depression, it was not generally possible to discriminate between major gene and polygenic transmission of susceptibility to illness. For a diagnostic scheme including only major depression as a manifestation of susceptibility to illness, there was a narrow range of lifetime population prevalence values (female prevalence ranging from 0.20 to 0.25, male prevalence set to 1/2 female prevalence) which yielded results compatible with major gene transmission. Linkage analyses for all markers yielded negative or inconclusive results. In one bipolar pedigree a lod score of 1.65 was found with a marker in chromosome 1 recommending further studies of this chromosome.

Alcohol-related symptoms in heterogeneous families of hospitalized alcoholics

Heterogeneity in the clinical symptoms of alcohol abuse was examined in 243 men and 305 women from families of hospitalized alcoholics, who had demonstrated different patterns of inheritance of susceptibility to alcoholism. Discriminant analysis was utilized to identify nine alcoholic symptoms that distinguished male relatives of alcoholic men from those of alcoholic women. Inability to abstain from alcohol, fighting and reckless driving while intoxicated, and alcohol treatment other than Alcoholics Anonymous were more prevalent in families of male probands. Male relatives of female probands experienced later onset of loss of control over drinking associated with benders, and cirrhosis and feelings of guilt. Female relatives of alcoholic men and women showed a marked predominance of the latter (Type 1) features, whereas male relatives had different clinical features, depending on the associated mode of inheritance.

Secular trends in the familial transmission of alcoholism

This is a study of the familial transmission of alcoholism in the families of 60 female and 240 male alcoholics ascertained in four psychiatric hospital units and in a local parole office. Eight hundred and thirty-one interviewed first-degree relatives and 125 spouses are included. The lifetime population prevalences of alcoholism in white males and females based on the Epidemiological Catchment Area Study in St. Louis were compared with the family rates. A semistructured comprehensive interview schedule (Home Environment and Lifetime Psychiatric Evaluation Record) was used and diagnoses made according to Feighner criteria for alcoholism. The methods of Survival Analysis established the presence of strong secular trends in the age-of-onset and lifetime prevalence of alcoholism in these families and in the general population. Accordingly, new methods for the analysis of family data that incorporate secular variation were developed. The Multifactorial Model of Disease Transmission was used to estimate familial correlations and these were parameterized by the "Tau" model of Familial Transmission. The model does not assume that all familial resemblance is due to genetic factors, but also includes the possibility of nongenetic transmission. Our analyses confirmed that more recently born cohorts of individuals had increased expected lifetime prevalences of alcoholism and decreased ages of onset, when compared with older cohorts. Separate age-of-onset distributions were required for males and females and the secular trends in age-of-onset were greatest in females. The differences between males and females were least in more recently born cohorts suggesting that sex-specific differences in the family and population distribution of alcoholism are decreasing.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial resemblance in energy intake: contribution of genetic and environmental factors

Total energy intake and intakes of carbohydrate, fat, and protein as well as the percentage of energy derived from these nutrients were calculated from a 3-d dietary record in 1597 subjects living in 375 families of French descent. Familial correlations were computed in pairs of biological relatives and relatives by adoption and used in the path-analysis BETA model to determine the contribution of genetic and nongenetic factors in the familial resemblance observed in energy intake. No significant genetic effect was found for intake of any nutrient tested (h2 less than or equal to 11%) and cultural inheritance was found to be more important than genetic inheritance. Nontransmitted environmental factors, including home environmental effects, were found to account for more than 50% of the variation observed in the energy-intake components. These results suggest that the average genetic influence on nutrient intake is negligible and that nongenetic effects associated mainly with home environmental effects are the major affecters of energy intake.

Genetic heterogeneity and the classification of alcoholism

Recent progress toward a systematic pathophysiological model of alcoholism has led to identification of two distinct subtypes of alcoholism. These subtypes may be distinguished in terms of distinct alcohol-related symptoms, personality traits, ages of onset, and patterns of inheritance. Type 1 alcoholism is characterized by anxious (passive-dependent) personality traits and rapid development of tolerance and dependence on the anti-anxiety effects of alcohol. This leads to loss of control, difficulty terminating binges once they start, guilt feelings, and liver complications following socially encouraged exposure to alcohol intake. In contrast, type 2 alcoholism is characterized by antisocial personality traits and persistent seeking of alcohol for its euphoriant effects. This leads to early onset of inability to abstain entirely, as well as fighting and arrests when drinking. Empirical findings about sex differences, ages of onset, associated personality traits, and longitudinal course are described in a series of adoption and family studies in Sweden and the United States. Implications for future research and clinical practice are discussed.

Effects of pentoxifylline on severe intermittent claudication

Pentoxifylline has been shown to improve treadmill walking distances under blinded, controlled conditions in patients with intermittent claudication. From the pooled data of a blinded, controlled, randomized, multicenter trial, the data from all enrolled patients with severe claudication (less than 70 m on treadmill at baseline) were evaluated. The treadmill data from these more severely ill patients were analyzed separately as a "severe subset" (placebo n = 17; pentoxifylline n = 21). No differences between the two treatment groups were observed in demography, history, or baseline treadmill walking distances. The initial claudication distance (ICD) improved 68% over baseline with pentoxifylline and 12% with placebo (p = .012) after twenty-four weeks of treatment. A new, derived efficacy variable was developed, "minimum distance walked," which tended to minimize psychological effects on treadmill performance. Over sixteen to twenty-four weeks of treatment, the pentoxifylline group improved 49% over baseline and the placebo group 3% (p = .019), when the "minimum distance walked" measurement was used. In this controlled trial the subset of patients with severe intermittent claudication benefited from pentoxifylline therapy.

Another look at the pentoxifylline efficacy data for intermittent claudication

Porter et al have reported that pentoxifylline shows statistically significant superiority over placebo in a seven-center, double-blind, parallel group, randomized trial of outpatients with intermittent claudication secondary to chronic occlusive arterial disease. The objective of this report is convey results of the intention-to-treat population, paying careful attention to relevant methodologic issues relating to the analysis of clinical trials. At the same time, a new measure of clinical efficacy, minimum distance walked, is proposed. The rationale for this measure is discussed and results are compared with those for walking distances at each visit. The reanalysis of the Porter et al data by "intention to treat" and by use of the minimum-distance-walked measure confirms the published findings of efficacy of pentoxifylline for treatment of intermittent claudication.

The familial transmission of bipolar illness

As part of the National Institute of Mental Health Collaborative Program on the Psychobiology of Depression study, data were collected on 2225 first-degree relatives of 612 probands. We analyzed 187 families of bipolar patients (149 probands with a diagnosis of bipolar I disorder and 38 with a diagnosis of schizoaffective, manic subtype). Using traditional genetic methods, the morbid risk of bipolar illness in relatives was found to be 5.7% in the relatives of bipolar probands as contrasted with 1.1% in the relatives of probands with major depression. These values compared closely with those obtained using survival analysis. Relatives of probands with early onset were found to have a greater risk than relatives of probands with late onset. The sex of the relative, the sex of the proband, or the subtype of the proband (bipolar I or schizoaffective bipolar) did not influence the risk in the relative. The age at onset was found to be accelerated with birth cohort, with individuals born in more recent cohorts having an earlier onset. Multifactorial analysis found significant heterogeneity for sex-specific sibling correlations (with the brother-sister correlation smaller than the same-sexed correlations), and path analysis estimated transmissibility of liability to be 71%. The mixed model, which allows for a single major locus with a multifactorial background, gave evidence for the presence of a major locus when controlling for the effects of birth cohort and age at onset. However, this evidence is tempered when comparing the mixed model with a more general transmission model.

Isolation and characterization of a nuclear depressive syndrome

We investigated the nosology of endogenous depression by numerical taxonomy. Five hundred and sixty-nine patients diagnosed as having unipolar major depressive disorder in the NIMH Clinical Research Branch Program on the Psychobiology of Depression-Clinical were studied. Thirty-six symptoms which might distinguish endogenous from non-endogenous depressions were chosen from the literature. Patients' symptom profiles assessed by structured interview were grouped by two methods: a K-means improvement of Ward's method of cluster analysis, and a latent class algorithm. The methods produced very similar groups and several internal validity criteria suggested that the groups were not spurious. Cluster 1, 'nuclear depression,' included a nucleus of patients common to multiple definitions of endogenous depression. The non-nuclear group scored as less neurotic than the nuclear group on personality tests administered during the index episode. The groups do not differ in frequency, number or severity of reported life events prior to onset of the index episode. The nuclear group shows a poor prognosis on two-year prospective follow-up, greater disturbance on personality inventories, and increased heritability of depression in siblings.

Familial rates of affective disorder. A report from the National Institute of Mental Health Collaborative Study

We examined familial rates of affective disorder and related illness in a cohort of 955 probands studied at five centers in the National Institute of Mental Health Collaborative Study of the Psychobiology of Depression: Boston, Chicago, Iowa City, New York, and St. Louis. Six hundred sixteen of these probands were entered into a family study, and 3423 of their first-degree relatives were evaluated. The probands were divided into five diagnostic groups: schizoaffective-bipolar (n = 37), schizoaffective-depressed (n = 18), bipolar I (n = 151), bipolar II (n = 76), and unipolar (n = 330). The relatives of bipolar I probands had a higher rate of bipolar I illness than the relatives of unipolar probands, but the relatives of unipolar probands did not have a higher rate of unipolar illness than the relatives of bipolar I probands. The relatives of probands with schizoaffective disorder, depressed subtype, had a higher rate of schizophrenia than the relatives of schizoaffective-bipolar probands, suggesting that bipolar schizoaffective disorder may be closer to pure affective disorder while schizoaffective depression may be closer to schizophrenia. An increase in bipolar II illness was also observed in the relatives of bipolar II probands. Overall, these data support the widely accepted distinction between bipolar and unipolar affective disorders.

Age-period-cohort analysis of secular trends in onset of major depression: findings in siblings of patients with major affective disorder

Analyses of data from the NIMH-CRB Collaborative Depression Study on age at onset of Major Depressive Disorder (MDD) in 1144 directly interviewed siblings of patients with major affective disorder show a strong secular trend toward increased lifetime risk and earlier onset in successive cohorts of birth since 1930. The proportionate increases in the instantaneous probabilities (hazard) of onset of MDD for each one year difference in year of birth were 5% for brothers and 7% for sisters. Age-period-cohort analysis suggests a powerful period effect may be responsible for this secular trend in rates of MDD, with rates of onset for siblings between 15 and 50 years of age doubling between the 1960s and 1970s. Possible artifacts are investigated.

The familial transmission of primary major depressive disorder

This is a study of the familial transmission of Primary Major Depressive Disorder in the families of 235 probands with this disorder ascertained as part of the NIMH-CRB Collaborative Depression Program. Eight hundred and twenty-six interviewed first degree relatives and 109 spouses are included. Research Diagnostic Criteria have been used and interviews were done using the SADS-L schedule. Prior analyses of these data have established the presence of strong secular trends in the age-of-onset and prevalence of Major Depressive Disorder in these families. Accordingly, new methods for the analysis of family data which incorporate secular variation were developed. Non-parametric Survival Analysis, using the Cox Proportional Hazards Model, guided the formulation of a quantitative family transmission model. Then a family analysis was conducted with the Multifactorial Model of Disease Transmission and the Tau Path Analytic Model. Using the non-parametric approach, only the sibs birth cohort, sex and affectational status of the mother were significantly related to the time of onset of illness in siblings. Proband sex, age-of-onset, and the presence of illness in the father were not significant. The quantitative analysis confirmed that more recently born cohorts of individuals had an increased expected lifetime prevalence and a decreased age-of-onset of Primary Major Depressive Disorder. Assortative mating was present and environmental factors common to siblings did not make a significant contribution to the phenotypic variance. Sex specific transmissibilities were found and the transmissibility in females (t2 = 0.62) was significantly greater than that of males (t2 = 0.28). There was a trend for the transmissibility of Primary Major Disorder to be greater in more recently born cohorts.

Etiologic heterogeneity in alcoholism

Etiologic heterogeneity in alcohol abuse was evaluated in 195 extended pedigrees, comprising 288 nuclear families of 140 male and 55 female Caucasian American hospitalized alcoholics. Previous adoption studies in Sweden demonstrated differential heritability of two patterns of alcohol abuse in men: type-2 alcoholism exhibited early onset of abuse associated with criminal behavior, while type-1 abuse began at a later age, uncomplicated by antisocial traits. Alcohol abuse in female Swedish adoptees was relatively homogeneous and similar to the late-onset, type-1 abuse. The notion of etiologic heterogeneity, as suggested by the Stockholm Adoption Studies, was examined in the American pedigrees by contrasting the models of familial transmission of susceptibility to alcoholism obtained via segregation analyses of families of male versus female probands. Families of male probands demonstrated significant familial resemblance, accounted for by a multifactorial-polygenic background in addition to a major (gene) effect. In contrast, familial resemblance in the pedigrees of female probands was attributed solely to a multifactorial-polygenic effect. We considered whether some families of male alcoholics were similar to families of female probands, who expressed type-1 abuse predominantly. Pedigrees of male probands were separated in two groups: (1) "female-like" families had a better likelihood for the model obtained for families of female probands than the one for families of all male probands, (2) "male-like" families had a better likelihood for the model of familial transmission describing families of all male probands. A statistically significant difference in the pattern of familial transmission was observed between the "male-like" and "female-like" groups. Discriminant function analysis of alcohol-related symptoms showed that the familial subtypes differed in clinical features as well. Alcohol abuse by male relatives in "male-like" families was characterized by the early onset of inability to abstain entirely from alcohol or lack of desire to stop drinking; in contrast, abuse in "female-like" families was characterized by late onset of guilt feelings and loss of control over binge drinking.

ECT in primary and secondary depression

The response of depressive symptoms to ECT was studied in 58 subjects who met DSM-III criteria for major depression. For data analysis, the sample was divided by diagnosis into categories of primary unipolar depression, bipolar depression, and secondary depression. Only 56% of the secondary depression group had a partial or complete remission of depressive symptoms, but 91% of the primary unipolar group and 100% of the primary bipolar group improved. Subdividing the secondary depression group by primary diagnosis revealed a differential response, with alcoholism and schizophrenia having the most favorable outcomes.

[Cancer mortality in the Thurgau canton 1970 and 1980 with a comparison between urban and rural areas]

As an addition to the recently published data by the Swiss Statistics Office in cooperation with the Swiss Cancer Registry, this report presents a microanalysis of trends in Canton Thurgau (185 000 inhabitants) based on the corresponding data. In the course of only 10 years the number of deaths due to cancer in rural areas has come to equal to that in city areas. This trend is particularly obvious for bronchial carcinoma in men. The decrease in mortality due to carcinoma of the stomach is more obvious in the urban population than in rural areas, a trend in which it can be assumed that environmental factors play a role. Further developments must be observed carefully, and corresponding analyses should also be performed in other cantons.

The family history approach to diagnosis. How useful is it?

Determining the rate to which various psychiatric illnesses are familial is one widely used method for validating diagnostic categories and determining the likelihood of genetic or nongenetic patterns of transmission. Data for these studies can be collected through direct interview of all available relatives (the family study method) or by obtaining information indirectly from the patient and other family members (the family history method). Information based on direct interview is usually considered to be more accurate, although the family history method permits collection of data on a larger and more comprehensive group of relatives. We explored the extent to which data collected by these two methods were in agreement. In general, the results confirmed the usefulness of the family history method. Although it has some limitations, such as underreporting, it has respectable sensitivity for many major diagnoses when broad but well-specified criteria are used.

The validation of the concept of endogenous depression. A family study approach

Depressive illnesses are subdivided into endogenous and nonendogenous types in psychiatry throughout the world. We used one method of validating this nosologic subdivision: the determination of the extent to which the disorder is familial. Rates of depression were examined in 2,942 first-degree relatives of 566 individuals diagnosed as having unipolar major depressive disorder. Because no single definition of endogenous depression is universally accepted, four different methods for defining endogenous depression were compared: the Newcastle Scale, the Research Diagnostic Criteria, DSM-III, and the definition of "autonomous depression" proposed by investigators at Yale University (New Haven, Conn). In general, no matter which definition was used, the relatives of the patients with endogenous illness did not have higher rates of depressive illness than those of the nonendogenous group. The Newcastle Scale was the most sensitive in picking up familial transmission of recurrent unipolar depression. The results of this investigation suggest that longitudinal approaches should be added to cross-sectional approaches for the best definition of endogenous depression.

Birth-cohort trends in rates of major depressive disorder among relatives of patients with affective disorder

As part of the National Institute of Mental Health-Clinical Research Branch Collaborative Program on the Psychobiology of Depression Clinical Study, 2,289 relatives of 523 probands with affective disorder were interviewed with the Schedule for Affective Disorders and Schizophrenia and diagnosed for major depressive disorder by the Research Diagnostic Criteria. Data were analyzed using life-table and survival methods. The findings suggest a progressive increase in rates of depression in successive birth cohorts through the 20th century and an earlier age at onset of depression in each birth cohort. A predominance of female depressives was found in all birth cohorts but the magnitude of female-male differences fluctuated over the decades. The existence of these trends is reported to stimulate further research. These findings are discussed in terms of possible gene-environment interactions. However, no conclusive causal inferences can be drawn pending further investigation.

Cerebral distribution of 133-Xe and blood flow measured with high purity germanium

Distribution of cerebral blood flow was measured with an array of 200 ultra-pure germanium radiation detectors and 133-Xe by inhalation. The array "sees" the head as a composite of different subvolumes and enables measurement of the concentration history of tracer every 1-10 sec in each subvolume simultaneously. Subvolume mean flows, (fm), and partition coefficients, lambda m, are derived by compartmental analysis of tissue concentration washout curves. Errors from "cross talk," scalp radiation, "look through," and assumed partition coefficients are eliminated. Average fm adjusted for 40 mm Hg PACO2 in 14 cortical subvolumes (7 right, 7 left) of four normal 21-24 year old controls ranged from 50 to 60 ml/100 cc tissue/min, and lambda m ranged from 0.97 to 1.14. Average fm and lambda m in white matter was 24 ml/100 cc/min and 1.42 - 1.14 respectively. During CO2 inhalation, right and left hemispheric fm increased 6.4% and 5.7%/mm Hg respectively, whereas white matter fm increased 2.2% and 3.4% mm Hg respectively. There was no systematic difference between front and back or dominant vs non-dominant sides. Three 73-84 year old controls had reduced fm and CO2 reactivity in all subvolumes, lambda m was in the same range as in younger controls. Two patients with intracranial cerebrovascular disease showed excellent localization of ischemic subvolumes. One patient with asymptomatic unilateral 98% stenosis of the internal carotid artery had a similar distribution of blood flow in both hemispheres.

Familial analysis of qualitative traits under multifactorial inheritance

The analysis of family data is described for qualitative multifactorial traits. For such a trait, affectational status is determined by an underlying liability distribution with one or more thresholds. The distribution of families (either selected at random or through probands) is used to estimate sex-specific parent-offspring and sibling correlations in liability and the prevalence in each sex. In contrast to using pairs of relatives, this approach permits estimation of age-specific population prevalences without a control sample. Moreover, by allowing for sex-specific correlations and a correlation between mates, path analysis can be used to model and test various cultural transmission models in addition to polygenic inheritance. Parameter estimation, hypothesis testing, and a goodness-of-fit test for path analytic models are described, and a computer program implementing these procedures is outlined.

Sex-related differences in depression. Familial evidence

After a description of threshold models of familial transmission based on an underlying continuous liability distribution, family data from the NIMH-CRB Collaborative Psychobiology of Depression Program-Clinical are described. No sex differences are found for bipolar illness, whereas female relatives have an increased rate of primary unipolar illness when compared to male relatives. This effect persists when relatives are classified according to recurrence, current illness, onset within the last 10 years, and treatment. Moreover, a cohort effect is present in the data and indicates a sex ratio close to one in the young cohort (less than or equal to 25). We considered the transmission of illness from parent to offspring by using survival analysis to examine the proportion of ill brothers and sisters of probands according to the affection status of parents. A maternal effect is found, with the mother having a greater influence on the liability of offspring of either sex. This is at odds with the notion that males and females have identical liabilities, but females have a lower threshold reflecting acknowledgement of more symptoms, etc. However, the mean difference in liability between the sexes may be due to systematic biological/cultural differences, with parental transmission contributing to variation about their means.

Pentoxifylline in the treatment of intermittent claudication of the lower limbs

Pentoxifylline, a methyl xanthine analogue was evaluated for treatment of intermittent claudication in a double-blind placebo controlled parallel group study in seven centers in the United States. Tests were performed on 128 cases, including 42 who took pentoxifylline (600 mg by mouth daily, increased stepwise to 1200 mg daily at the end of one month) and 40 who took placebo for 24 weeks. Twenty-five patients on pentoxifylline and 21 on placebo were dropped from the study for reasons unrelated to the drug. Walking ability on a treadmill was increased significantly after 2 weeks and remained so throughout the study in the pentoxifylline vs. the placebo group. Ability to walk until first experiencing intermittent claudication was a more sensitive index than the maximum ability to walk. The drug did not cause changes in blood pressure or in heart rate. Other than mild nausea, there were no significant side effects.

A family study of bipolar II disorder

Professional raters who were blind to proband diagnosis used the schedule for affective disorders and schizophrenia (SADS-L) and the Research Diagnostic Criteria (RDC) to evaluate 1,210 first-degree relatives of 327 probands with primary major depression, participating in the family sub-study of the NIMH Collaborative Study of the Affective Disorders--Clinical Branch. Bipolar II probands were significantly more likely to have bipolar II relatives than were non-bipolar or bipolar I probands. Bipolar II probands were slightly more likely than non-bipolar probands and slightly less likely than bipolar I probands to have relatives with bipolar I illness. Similar patterns have emerged in two other recently reported family studies of bipolar II illness. Taken together, these data suggest heterogeneity among patients with bipolar II depression. Some appear to be genotypes for bipolar I illness, while a small proportion may be genotypes for non-bipolar illness. A third group, of undetermined size, may breed true.

Primary and secondary affective disorder: Part III. Longitudinal differences in depression symptoms

Depressed inpatients (29 primary and 31 secondary) were blindly rated at several time points on 137 depressive symptoms. Of the 7 high-frequency symptoms or symptom clusters analyzed, significantly greater symptom persistence was seen for secondary depressives on low mood, pessimism, change in usual interests, and suicidal ideation. Day-to-day variability in symptoms did not differ between groups. Scalability of symptoms (Guttman scales) was acceptable for primary but not secondary depressives. Suicidal ideation tended to be the first symptom to remit in primary depression but persisted in the secondary group, even after remission of the most severe symptom. Implications for treatment are discussed.

HLA and major affective disorder

Fifteen unrelated multiplex families, each containing two or more offspring with a diagnosis of major affective disorder, were HLA typed to provide additional data bearing on the proposed linkage of affective disorder susceptibility genes with the major histocompatibility complex on chromosome 6. Altogether 19 parents, 38 affected children, and 13 unaffected children were typed. The distribution of shared HLA haplotypes among pairs of affected siblings, pairs of affected-unaffected siblings, and various diagnostic subsets of these families fails to lend any support for the HLA linkage hypothesis.

The Cincinnati Lipid Research Clinic family study. Bivariate path analyses of lipoprotein concentrations

Methods for the analysis of the joint transmission of two phenotypes are described and used to determine the extent to which lipoprotein concentrations share a common genetic and/or environmental background. Analysis of data on 160 Caucasian nuclear families revealed that the observed phenotypic association between high-density cholesterol (HDL) and low-density cholesterol (LDL) could be accounted for in terms of common family environmental effects alone (estimated genetic correlation, ρG = −0·132±0·136; estimated residual environmental correlation, ρR = 0·065±0·230). The association between HDL and very-low-density cholesterol (VLDL) could not be accounted for in terms of family environmental effects alone. For HDL and VLDL the residual environmental correlation was significant while the genetic correlation was not (ρG = −0·111±0·214, ρR = −0·421±0·172). The correlation between LDL and VLDL also could not be accounted for in terms of common family environmental effects alone, although here a genetic relationship appears to be the important factor (ρG = 0·330±0·192, ρR = 0·010±0·217).

Genetic analysis of manic-depressive illness

Two threshold models, a single locus model, and two combined models are fitted to data on familial incidence of bipolar affective disorder in 194 nuclear families ascertained through a bipolar proband. The relative fit of alternative transmission models is tested by a likelihood ratio chi-square with the degrees of freedom defined by the difference in the number of parameters estimated by each model. All parameters are estimated by the method of maximum likelihood. The simplest threshold model, permitting only a single background familial correlation, is found to provide a statistically poorer fit than any of the alternative models, and may be rejected as a model for the etiology of bipolar affective disorder. The four remaining models are statistically indistinguishable. It is suggested, however, that the involvement of a major locus in the etiology of this disorder deserves further scrutiny since any of the models incorporating a major locus, with or without a multifactorial background, are consistently associated with greater likelihoods than the complex threshold model. It is also noted that diagnostic criteria are critical in the analysis. In the present study, relatives of probands are considered affected if a diagnosis of bipolar or unipolar affective disorder is present. When only bipolar relatives are considered affected, none of the transmission models may be rejected. Finally, the results of these analyses are found to be independent of the ascertainment parameter.

A defense of path analysis in genetic epidemiology

Contemporary models of multifactorial inheritance are described and justified from the perspective of their intended use in genetic epidemiology and their developmental sequence. Substantial empirical data and statistical theory support the practical adequacy of the assumptions of path analysis for most multifactorial traits that show vertical inheritance. The choice of scale for quantitative traits must be considered on an individual basis. From both biological and statistical perspectives, transformations of scale may be more appropriate for analysis than the measurements are themselves. Recent criticism of contemporary models and computational procedures is based on a caricature of path analysis rather than on the method as it is actually practiced. The utility of path analysis is primarily limited by an investigator's biological insight and analytical skill, not by the method's assumptions. Model-free descriptive statistics are inherently inadequate to characterize the stable and autonomous features of the underlying mechanisms that generate observable variation in multifactorial traits. In contrast, path analysis has led to remarkably stable estimates of structural parameters for a wide variety of important biological traits. While exploratory methods can be useful for preliminary data inspection, they cannot substitute for formal tests of hypotheses based on explicit, falsifiable models.

HLA and disease: haplotype sharing in multiplex families

Recently it has been argued that the distribution of shared haplotypes in multiplex sibships for HLA-associated diseases may be an indicator of the disorder's underlying mode of transmission. Specifically, it has been suggested that the presence of multiple disease susceptibility genes and/or loci may be inferred when an inverse relationship between the amount of haplotype sharing and the number of affected sibs is observed in families where neither parent is affected. This claim is evaluated using extensive computer simulations. It is shown that a variety of haplotype sharing patterns are possible, even for the simplest models, and that for a large segment of the parameter space the actual distribution of shared haplotypes is opposite to that predicted. Accordingly, the inference that more than one locus is involved in the etiology of an HLA-associated non-Mendelian disease, if based only on the distribution of shared haplotypes in multiplex sibships, is unjustified.

Hyperbaric-oxygen treatment of multiple sclerosis. A randomized, placebo-controlled, double-blind study

Several uncontrolled studies have suggested a beneficial effect of hyperbaric oxygen on multiple sclerosis. We studied 40 patients with advanced chronic multiple sclerosis who were randomly divided into two matching groups. The experimental group received pure oxygen, and the placebo group received a mixture of 10 per cent oxygen and 90 per cent nitrogen; both groups were treated at a pressure of 2 atmospheres absolute for 90 minutes once daily, for a total of 20 exposures. Objective improvement occurred in 12 of 17 patients treated with hyperbaric oxygen and in 1 of 20 patients treated with placebo (P less than 0.0001). Improvement was transient in seven of the patients treated with oxygen and long-lasting in five. Those with less severe forms of the disease had a more favorable and lasting response. At one year of follow-up, deterioration was noticed in 2 patients (12 per cent) in the oxygen group, neither of whom had had an initial response, and in 11 patients (55 per cent) in the placebo group, one of whom had had a positive initial response (P less than 0.0008). Minor ear problems and reversible myopia were the only side effects observed. These preliminary results suggest a positive, though transient, effect of hyperbaric oxygen on advanced multiple sclerosis, warranting further study. This therapy cannot be generally recommended without longer follow-up periods and additional confirmatory experience.

Investigation of the membrane-fluidizing properties of porphyrin-inducing drugs

The objective of this study was to test the hypothesis that porphyrin-inducing drugs act at least in part by disrupting membrane lipids. The porphyrin-inducing steroids, 3 alpha-hydroxy-5 alpha-pregnane-11,20-dione (alfaxalone) and 3 alpha-hydroxy-5 alpha-pregnan-20-one induce considerably greater fluidity changes in spin-labelled phospholipid-cholesterol bilayers than do the corresponding 3 beta-hydroxy steroids which are also less potent as porphyrin inducers. The steroids did not cause any significant change in spin-labelled vesicles lacking cholesterol. The porphyrin-inducing compound 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine and a series of analogues caused fluidity changes in phospholipid bilayers in the presence and absence of cholesterol. The porphyrin-inducing nonplanar 2,2',4,4'-6,6'-hexachlorobiphenyl caused a significant change in bilayer fluidity in phospholipid bilayers in the presence and absence of cholesterol. Since the planar 3,3',4,4'-tetrachlorobiphenyl, allylisopropylacetamide (AIA), and griseofulvin are potent porphyrin-inducing compounds, but do not fluidize a lipid bilayer, it was clear that the original hypothesis required modification. No evidence could be obtained to support the idea that a subset of porphyrin-inducing drugs exists which are membrane fluidizers and whose common mechanism of action as porphyrin-inducers might be revealed by a common pattern of porphyrin accumulation in chick embryo liver cells. It is suggested that those porphyrin-inducing compounds with membrane-fluidizing properties might fluidize the nuclear membrane, thus facilitating the transfer of an induction specific RNA for delta-aminolevulinic acid synthetase from the nucleus to the cytoplasm.

Refutation of the general single-locus model for the etiology of schizophrenia

All published studies on the familial incidence of schizophrenia appropriate for testing the applicability of the general single-locus two-allele model are examined under the assumption of a unitary etiology for all schizophrenia. We show that the single major locus model is inadequate to predict the incidence in four classes of relatives of schizophrenic probands (parents, siblings, monozygotic, and dizygotic cotwins). In addition, the observed proportion of affected offspring from dual matings differ significantly from the model's prediction. The lack of an overall fit between the published familial distributions and the monogenic model suggests that a single major locus is insufficient for the etiology of schizophrenia. Further efforts in examining multifactorial models, mixed models, and other transmission models may be fruitful.

Pentoxifylline efficacy in the treatment of intermittent claudication: multicenter controlled double-blind trial with objective assessment of chronic occlusive arterial disease patients

The efficacy, safety, and tolerance of pentoxifylline (Trental, Hoechst-Roussel Pharmaceuticals, Inc.) in the treatment of intermittent claudication associated with chronic occlusive arterial disease (COAD) were evaluated in a double-blind, placebo-controlled, parallel-group, multicenter clinical trial involving a total of 128 outpatients. The response to treatment was ascertained at regular intervals during the trial by measuring the distance walked prior to the onset of claudication when patients were subjected to a standardized treadmill test. Pentoxifylline given orally in doses up to 1200 mg/day was significantly more effective than placebo in increasing both the initial and absolute claudication distances in patients with COAD. Reduction of lower limb paresthesias also suggested greater clinical improvement in the pentoxifylline treated patients. These results support the hypothesis that pentoxifylline reduces blood viscosity by improving red cell flexibility, and thereby enhances blood flow in patients with COAD. White the precise mode of therapeutic action requires clarification, pentoxifylline was well tolerated with minimal unwanted effects.

Ascertainment bias for non-twin relatives in twin proband studies

When families are ascertained through affected twins, as for example when twin probands are selected from a registry and their non-twin relatives studied, a correction for ascertainment bias is needed. It is shown that probandwise counting (where relatives of doubly ascertained twin pairs are counted twice) is the appropriate method. The bias resulting from pairwise counting is given and depends on the genetic model and on the probability of selecting an affected twin as a proband. For the multifactorial and generalized single major locus models the bias is small, and the problems associated with nonindependent ascertainment are negligible in practice.

Inbreeding and the genetic control of nondisjunction

We have studied the frequency of trisomics in newly formed zygotes and the proportion of trisomics, k, coming from consanguineous marriages by assuming that recessive genes at a single locus or multiple loci are responsible for the induction of nondisjunction. For mitotic nondisjunction, the value of k increases as the magnitude of consanguinity of the parents increases, but the opposite relationship holds for meiotic nondisjunction. Therefore, it is important to distinguish mitotic and meiotic types in the genetic study of nondisjunction. This seems to be one of the simplest tests for detecting the genetic control of nondisjunction.

An ultrapure germanium detector array for quantitating three-dimensional distribution of a radionuclide: a study of phantoms

A new stationary 200-element ultrapure germanium (HPGe) array has been tested for accuracy and sensitivity in quantitating the distributed concentration of single-gamma-emitting radionuclides in phantoms approximating the size of the human brain. The phantoms consisted of 42 blocks of 39.1 cm3 average volume. Fourteen different permutations were studied. The concentrations in the blocks varied from 0i to 4.64 muCi/cm3. This first-generation instrument makes it possible to reconstruct the distributed concentration with a mean relative error of 8.3% at 200,000 counts per sample (1,000 counts/detector), and has sensitivities of 6,200 and 12,000 cps, respectively, for 1 muCi/cm3 of Xe-133 and Tc-99. The reconstruction algorithm is based on the conjugate gradient method of solving the set of linear equations that account for geometric, attenuation, and scatter factors. The results have implications for measuring the distribution of the partition coefficients, blood flow, blood volume, and concentration of tracers emitting single gamma photons in 42 anatomic subvolumes (30 cm3 average) of the entire brain simultaneously.