Clinical and methodological factors related to reliability of the best-estimate diagnostic procedure

OBJECTIVE

The reliability and accuracy of the best-estimate diagnostic procedure were examined, and factors associated with reliability were determined.

METHOD

The subjects were 134 members of large multigenerational pedigrees densely affected by bipolar disorders or schizophrenia. Three best-estimate diagnoses were derived: first, by a research psychiatrist and research assistant unblind to the relatives' diagnoses; second, by two blind independent psychiatrists; third, by a panel of four blind psychiatrists. The subjects were characterized on several clinical and methodological variables, which were used to compare the agreements of two types of best-estimate diagnoses with the disagreements.

RESULTS

There was satisfactory agreement between the unblind and blind consensus best-estimate diagnoses and between the two blind independent psychiatrists. Latent class analyses revealed that limited sensitivity was the main source of imperfect reliability. Confusability analyses revealed that the most problematic diagnostic distinctions involved schizoaffective disorder, which was confused with schizophrenia, bipolar I disorder, and schizophreniform disorder. Blindness significantly affected diagnostic outcome in latent class analyses. Moreover, for diagnostic disagreements, unblind diagnoses had greater continuity with the most predominant diagnosis in the pedigree than did blind diagnoses. Diagnostic disagreements were associated with the presence of mixed affective and psychotic symptoms, less diagnostic certainty, and shorter duration of illness.

CONCLUSIONS

These results suggest that it is possible to identify cases that are more likely to lead to diagnostic disagreements in family and epidemiological studies and that blind diagnoses may help to prevent false positive diagnoses, which may be particularly detrimental to genetic linkage analyses.

Genetic studies of neuropeptide Y and neuropeptide Y receptors Y1 and Y5 regions in morbid obesity

Synthesis and release of neuropeptide Y (NPY) are both regulated by leptin binding to its hypothalamic receptor mediating some of the effects of leptin on food intake. Moreover, NPY administration is a powerful stimulant of feeding behaviour. Thus, we investigated the potential implication of NPY, NPY-Y1 and -Y5 subtype receptors [rNPY-Y1/-Y5] in the development of human obesity. Two complementary genetic approaches were used: 1) linkage analyses between obesity and polymorphic markers located nearby NPY and rNPY-Y1/-Y5 genes (respectively on chromosomes 7p15.1 and 4q[31.3-32]) in 93 French Caucasian morbidly obese families; 2) single strand conformation polymorphism (SSCP) scanning of the coding region of the NPY and rNPY-Y1 genes performed in 50 unrelated obese patients ascertained on the basis of a body mass index of 27 kg/m2 or more and a family history of obesity. No evidence of linkage between morbid obesity or obesity-related quantitative traits and NPY and rNPY-Y1/ Y5 regions was found in this population. Moreover, SSCP scanning revealed no mutation in the coding region of NPY and rNPY-Y1 genes among obese subjects. These results suggest that NPY and NPY-Y1/ Y5 receptors are unlikely to be implicated in the development of human morbid obesity, at least in the French Caucasian population.

6p24-22 region and major psychoses in the Eastern Quebec population. Le Groupe IREP

Recent reports of a linkage trend in 6p24-22 for schizophrenia (SZ), in different samples, were tempered by the concurrent evidence of negative reports in other samples. In the studies showing positive results, different definitions of affection and a wide spectrum of diagnoses were used. Our objectives were not only to test for linkage at 6p24-22 in the Eastern Quebec population, but also to test whether this putative vulnerability locus was either selectively linked to schizophrenia (SZ), or to bipolar disorder (BP), or to both major psychoses. Parametric and nonparametric linkage analyses with 12 microsatellite markers in 6p24-p22 were performed on a sample of 18 large multigenerational pedigrees (N = 354) either affected by SZ, or by BP, or equally affected by both major psychoses (i.e., mixed pedigrees). Three affection definitions were usually tested in our program: one on schizophrenia (SZ), one on bipolar disorder (BP), and one that comprised SZ and BP under the hypothesis of a susceptibility locus common to both in major psychoses (common locus, CL). The results of parametric analyses did not support a major gene hypothesis. However, in one large mixed pedigree (#151), we observed with the common locus phenotype (CL) lod scores of 2.49 and 2.15, respectively, at the D6S296 and D6S277 loci under a dominant model. Our data suggest the presence of a potential vulnerability locus at 6p24-22 that could be related to both schizophrenia and bipolar affective disorder. These results may be seen as congruent with former studies that used schizoaffective as well as schizophrenia diagnoses as entry criteria for the affected families, and used an affection definition that comprised affective psychoses as well as schizophrenia.

Family history of cognitive disabilities in first-degree relatives of autistic and mentally retarded children

We compared with a family history method the rate of cognitive disabilities (CD) in 156 first-degree relatives of 49 autistic (AU) probands to that found in 55 first-degree relatives of 18 mentally retarded (MR) probands. Broadly defined CD were found in, respectively, 17 and 16% of the relatives of the AU and MR probands. However, the characteristics of the probands associated with a family history of CD are different in AU and MR: Female and low IQ AU probands have more first-degree relatives with CD. Our findings suggest that a positive family history of CD is not specific to autism when compared to mental retardation. The observation that female and low IQ probands have higher family history of CD may suggest heterogeneity within autistic children and provides leads for future family studies.

Long-term stability of diagnosis and symptom dimensions in a systematic sample of patients with onset of schizophrenia in childhood and early adolescence. II: Postnegative distinction and childhood predictors of adult outcome

BACKGROUND

The aim of this study was to verify the presence and stability across life of the positive/negative distinction in early-onset schizophrenia (EO-SZ) through a longitudinal factor analysis of the schizophrenic dimensions, and to identify the factors predicting several indices of long-term outcome for EO-SZ.

METHOD

Forty children consecutively referred for DSM-III-R schizophrenia (SZ) in a specific catchment area comprised the sample.

RESULTS

Across a 14.8-year follow-up, longitudinal factor analysis identified two separate factors corresponding to the positive and negative symptom dimensions. We also observed that: the GAS rated over the last three years of adult illness and the severity of negative symptoms during the stabilised interepisode intervals in adulthood were the indices of adult outcome that were most easily predicted; and the best childhood predictors of adult outcome were premorbid functioning and severity of positive and negative symptoms during acute episodes.

CONCLUSIONS

The presence of premorbid non-psychotic behaviour disturbances (NPBD) and premorbid developmental problems was not related to severity of outcome, in contrast to the former variables.

Long-term stability of diagnosis and symptom dimensions in a systematic sample of patients with onset of schizophrenia in childhood and early adolescence. I: nosology, sex and age of onset

BACKGROUND

Little is known about the long-term outcome of schizophrenia that has its onset during childhood and early adolescence (early-onset schizophrenia, or EO-SZ). Whether or not EO-SZ is an aetiologically separate form of schizophrenia (SZ) is unresolved.

METHOD

The study was a 14.8-year follow-up, using methods such as systematic sampling, evaluation of possible non-respondent bias, consensus best-estimate diagnoses (DSM-III-R) made independently in childhood and adulthood, measures of positive and negative dimensions, of non-psychotic behaviour disturbances (NPBD) and of developmental problems before the appearance of SZ.

RESULTS

There was high stability of EO-SZ (n = 40) diagnoses (mean onset at 14.0 years) until adulthood (mean age at follow-up 28.8 years) but a lower stability of positive and negative schizophrenic dimensions. There was a poor outcome of EO-SZ, a strong over-representation of males but few gender differences, and no effect of age of onset on clinical features and outcome.

CONCLUSIONS

EO-SZ taken as a whole shows no qualitative differences to adult-onset SZ. However, a distinction through the onset of preschizophrenic developmental problems or NPBD might be a way to investigate heterogeneity within EO-SZ.

Chemiluminescent and colorimetric enzymatic assays for the detection of PCR-amplified Salmonella sp. products in microplates

To improve Salmonella detection, we developed nonradioactive hybridization assays of amplified products from pure Salmonella cultures. Biotin-labeled PCR products were trapped by internal probes covalently bound to CovaLink-NH MicroWells and detected by colorimetric or chemiluminescent enzymatic reactions. The sensitivities of colorimetric assays using peroxidase and alkaline phosphatase were similar to those obtained with an ethidium bromide-stained agarose gel; both procedures allow the detection of 50 Salmonella cells. Chemiluminescence was 10-fold more sensitive than colorimetry.

Loa loa: structural diversity of a 15-kDa repetitive antigen

A ladder antigen of Loa loa was identified on Western blots of all life cycle stages probed with loaisis sera. The smallest subunit has a relative M(r) of about 15 kDa and larger subunits represent size increments of 15.0 kDa. An 1800-bp genomic clone encoding this antigen was characterized further by restriction mapping. Southern blot analysis, and nucleotide sequencing. The antigen is encoded by multiple copies of a gene, linked in tandem repeats of 396 bp, each of which encodes 132 amino acids. These repeats have diverged sufficiently to produce distinct restriction enzyme sites and Southern blot hybridization patterns. The 1764-bp insert contains no introns and encodes 588 amino acids, representing one incomplete and four complete repeats. At the 3' end of three repeats, there are consensus proteolytic cleavage sites; one repeat has no cleavage site. Two perfect repeats show a 93.9% amino acid identity with one another; the rest of the repeats, despite being adjacent to one another, show only 31-42% identical amino acids. Putative asparagine N-linked glycosylation sites are expressed by only two of the repeats. Despite this structural diversity, each L. loa repeat showed homology to Ascaris suum allergen and the homologue protein described in Dirofilaria immitis and Brugia pahangi.

Combination therapy with zidovudine and didanosine compared with zidovudine alone in HIV-1 infection

OBJECTIVE

To assess safety, pharmacokinetics, and in-vivo virologic activity of five different combination regimens of zidovudine and didanosine compared with zidovudine alone in patients with human immunodeficiency virus type 1 (HIV-1) infection.

DESIGN

Open-label, partially randomized, dose-ranging study.

SETTING

University-affiliated, medical center clinics.

PATIENTS

A total of 69 patients with HIV-1 infection, CD4+ cell counts fewer than 400 cells/mm3, and fewer than 121 days of previous zidovudine treatment.

INTERVENTIONS

Fifty-five patients received combination therapy with zidovudine and didanosine, and 14 received zidovudine therapy alone (600 mg/d). Daily dosages in milligrams of zidovudine and didanosine, respectively, in the five combination groups were 150 and 90 mg, 300 and 334 mg, 600 and 334 mg, 300 and 500 mg, and 600 and 500 mg.

MEASUREMENTS

CD4+ cell counts, HIV-1 RNA titers in plasma, and toxic effects.

RESULTS

The combination regimens were associated with higher and more sustained increases in CD4+ cells than zidovudine alone, even after adjustment for initial CD4+ counts and previous zidovudine therapy (P < 0.001). The median increase in CD4+ cell counts was 166 cells/mm3 with combination therapy and 77 cells/mm3 with zidovudine alone (P = 0.001) and did not differ statistically among the five combination regimens. Human immunodeficiency virus type 1 RNA titers in plasma decreased in 15 (83%) of 18 combination-therapy recipients compared with 2 of 7 zidovudine-alone recipients (P = 0.017). No pharmacokinetic interactions were seen between zidovudine and didanosine. Toxicity rates were low among all treatment groups. A greater decrease in hemoglobin levels was seen with the regimen using zidovudine alone (-8 g/L) compared with combination regimens using the same zidovudine dose (-1.5 g/L, P = 0.03).

CONCLUSIONS

Combination therapy with zidovudine and didanosine produced larger and more sustained increases in CD4+ cell counts, more frequent decreases in plasma HIV-1 RNA titers, and more stable hematologic status than zidovudine therapy alone. The effects of this combination on the progression of HIV disease merit further study, to provide information about clinical outcome, because this was a relatively small study based on surrogate markers of HIV-1 infection.

Socioeconomic status and prediction of ventricular fibrillation survival

OBJECTIVES

The association between socioeconomic status and cardiac arrest is less well known than some other associations with cardiac arrest. We used property tax assessments as a measure of socioeconomic status in a study of victims of out-of-hospital cardiac arrest found in ventricular fibrillation.

METHODS

We studied patients attended by the Seattle Fire Department's emergency medical services system between May 1986 and August 1988. During the period studied, 356 episodes met the study criteria; 114 (32%) of these patients survived without major neurologic deficit. Residential property tax assessments were available for 253 of the patients.

RESULTS

After adjustments were made for age, witnessed collapse, bystander-initiated cardiopulmonary resuscitation, time from call to paramedic arrival, activity, location of collapse, and chronic morbidity, an association of survival with greater assessed value per living unit was observed. An increase of $50,000 in value per unit was associated with a 1.6-fold increase in survival rate.

CONCLUSIONS

Not only are persons in the lower socioeconomic strata at greater risk for cardiac mortality, but they are also less likely to survive an episode of out-of-hospital cardiac arrest.

Surgical pathology of the intervertebral disc. Is routine examination necessary?

A retrospective review of 508 charts of patients undergoing laminectomy for all reasons was carried out with special attention to the preoperative diagnosis, postoperative diagnosis, pathologic diagnosis, and discharge diagnosis. The elimination of routine pathologic examination of surgical discectomy specimens would not have lowered the standard of care; the pathologist's report had no discernible influence on patient management. Unusual clinical features will continue to require careful examination of surgical specimens by the pathologist. Millions of healthcare dollars can be saved by eliminating this routine examination, which is based on outmoded routines. Hospital medical staffs who wish to change this practice must revise their hospital bylaws in keeping with the standards of the The Joint Commission on Accreditation of Healthcare Organizations (JCAHO).

Psychiatric status of adolescents who had extreme temperaments at age 7

Two temperamentally extreme (extremely easy and extremely difficult) subgroups of children were selected at the age of 7 years from a large random sample of the general population of Quebec City. The clinical status, family functioning, IQ, and academic performance of these children were reassessed at 12 and 16 years of age. Findings suggest that extreme temperament at age 7 predicts psychiatric status in preadolescence and adolescence only when family functioning is also taken into account. The adolescents who had been temperamentally difficult children and who were living in families with dysfunctional behavior control displayed more clinical disorders.

Extreme temperament and diagnosis. A study in a psychiatric sample of consecutive children

We report on an epidemiological-clinical study of the New York (NY) Longitudinal Study temperament model in a consecutive sample of children (N = 814) referred to a child psychiatric center. Temperament comparisons in this clinical population were made by using temperament normative values obtained in previous random samples of the general population in the greater Quebec City (Canada) area. Different clinical diagnostic groups (externalized disorders, developmental delays, and mixed disorders) were derived from a review of the entire hospital charts in which the interrater reliability was tested and performed "blind" to temperament scores. The diagnostic groups were confirmed through discriminant function analyses. The results (1) replicated, in this child psychiatric population, two factors of temperament similar to those previously found in random samples of our general population; (2) showed, in the psychiatric population of children, an overproportion of difficult temperaments on both factors; (3) confirmed conversely that a large proportion of children referred for a disorder did not present with an extreme temperament, and, therefore, an extreme temperament and a clinical disorder were not equivalent; and (4) suggested a specificity in the relationship between particular temperament factors and the type of clinical problem. Temperament factor 1 (withdrawal from new stimuli, low adaptability, high intensity, and negative mood) was found to be more associated with externalized disorders (opposition, conduct, or attention-deficit disorders), whereas temperament factor 2 (low persistence, high sensory threshold, and high mobility) was found to be more associated with specific developmental delays. The findings provided leads for future clinical research on temperament, family functioning, and child psychiatric diagnoses.

Significance of extreme temperament in infancy for clinical status in pre-school years. I: Value of extreme temperament at 4-8 months for predicting diagnosis at 4.7 years

The relationship between extreme temperament in infancy and clinical status at 4.7 years of age was studied in temperamentally different groups of infants matched for sex and SES, and subselected from a large birth cohort representative of the general population. The effects of certain dimensions of family functioning and of other risk factors were examined. By itself, extremely difficult temperament in infancy had no strong direct association with clinical outcome at four years of age, whereas temperament assessed at four, family attitudes to discipline, and stressful events did. However, extreme temperament in infancy might indirectly affect outcome through its association with temperament at four. The interplay between adverse temperament and parental attitudes of discipline previously observed in middle childhood might have antecedents in pre-school years.

Significance of extreme temperament in infancy for clinical status in pre-school years. II: Patterns of temperament change and implications for the appearance of disorders

Few, if any, of children's behavioural or cognitive characteristics assessed in the first years of life demonstrate stability until later childhood; early characteristics have so far failed to show an association with future psychopathology. This longitudinal study, from 4-8 months to 4.7 years old, focused on stability and change of extreme temperamental traits in groups of infants subselected from a large birth cohort. Persistent extreme temperament at four and eight months old did not increase stability of temperament to four years of age, relative to other children in the whole population. Sizeable change occurred, and the environmental parameters associated with negative temperamental change did not seem to be the same as those related to positive change. Boys with extreme scores were more stable, while girls appeared more prone to positive change. It is hypothesised that the direction of temperamental change in the first years could be more meaningful for long-term prediction of disorders than any one assessment of temperament taken at any one year.

The use of dense alumina-alumina ceramic combination in total hip replacement

The purpose of this article was to review the laboratory and clinical performances since 1970 of a total hip prosthesis using alumina-alumina combination. The chemical and physical properties of dense alumina ceramic were studied in relation to biocompatibility, mechanical strength, and surface properties. Through the examination of 35 retrieved implants, it was found that the long-term success of alumina-alumina total hip replacement depends on both the ceramic microstructure (small grain size with uniform distribution, minimum porosity, absence of inclusions) and implant geometry (sphericity deviation +/- 1 micron, radius tolerance between components 7-10 microns). Alumina component wear and fractures have disappeared with the use of high-performance materials and severe manufacturing quality control. Examination of human biopsies from well-fixed prostheses showed that alumina particles deposits increase with time with only a low-grade macrophagic reaction. When loosening occurred, an inflammatory reaction appeared; this reaction was less striking than with loose metal-polyethylene prostheses, however. The long-term behavior of cementless alumina cup fixation depends upon initial positioning and stability; survivorship analysis of the cemented ceramic cups showed an 88% survival probability after 8 years with a 1.6% average annual probability of revision. The percentage of surviving was 100% after 8 years in patients who were less than 50 years old. Aseptic loosenings occurring at the cup-cement interface were assumed to be related to stress protection secondary to the high rigidity of the ceramic leading to a weakening of the spongious bone supporting the cement mantle. Good bone stock quality as well as high-quality ceramic appear to be the prerequisites for durable fixation of alumina sockets.

Cognitive development and reading achievement in pervasive-add, situational-add and control children

Studies on hyperactivity have shown the importance of distinguishing hyperactive children according to the pervasiveness of their symptoms. To verify the meaningfulness of this distinction in Attention Deficit Disorders, an epidemiological study was undertaken. Sixteen pervasive-ADD, nine situational-ADD and 28 non-ADD children selected from a general population were compared using different measures. The results show that pervasive-ADD differ from non-ADD children on verbal IQ and reading difficulties and support the distinction of ADD according to the pervasiveness of the symptoms.

Temperament and intellectual development: a longitudinal study from infancy to four years

Using three temperamentally different subgroups from a large birth cohort, the authors undertook a longitudinal study of the association between temperament measured in children at 4 and 8 months and IQ assessed at 4.7 years. The data suggested a strong effect of extreme temperament traits on IQ development in middle and upper socioeconomic classes and in families with superior functioning in terms of communication. The temperamentally difficult group unexpectedly displayed higher IQs, and the well-replicated effect of socioeconomic status on IQ development was observed mainly in this group. These data support the hypothesis that difficult infants activate special family resources, which stimulates intellectual development over the years.

A hand-held decision-aid system designed for rural health workers

A great part of the world's population is cared for by rural health workers who are also collecting data for epidemiological studies. These workers have a low level of medical training and are working in a poor technical environment. At the request of an international humanitarian and medical organization (Médecins Sans Frontières), we have developed an integrated (hardware and software) system, TROPICAID, based on a hand-held computer and designed to increase rural health workers' efficiency. The software is easy to use and enables users to get information from an internal data base on 60 drugs. The decision-making module analyzes the patient's parameters (460 different symptoms are recognized) and indicates possible diagnoses (the system knows 210) and relevant treatments. In addition, the system facilitates the collection of medical data for elementary statistical analysis. The computer, which is lightweight (1.5 kg) and compact, runs on battery power for up to a week in normal use. The program which is written in Pascal and data are stored in high-capacity EPROMs. An early trial in Chad with Médecins sans Frontières has shown the value of such a project as well as a few weaknesses to be overcome.

Value of difficult temperament among 7-year-olds in the general population for predicting psychiatric diagnosis at age 12

The authors assessed the predictive value of "difficult" temperament, as defined in the New York Longitudinal Study, in 12-year-old children from the general population of Quebec City whose temperaments had been determined to be difficult or easy at age 7. The difficult and easy temperament groups were balanced for age, sex, and socioeconomic status. The authors used many convergent measuring devices and were blind to the temperament scores of the children at age 7. Temperamentally difficult children had more clinical disorders at age 12 that qualified for a DSM-III diagnosis. An association with family dysfunction in terms of behavior control seemed to increase this risk: there was a lower rate of clinical disorders among children in superior functioning families than among those in dysfunctional families.

Follow-up of a randomized trial for oat cell carcinoma evaluating the efficacy of peripheral intravenous nutrition (PIVN) as adjunct treatment

A randomized trial was initiated to compare the effects of peripheral i.v. nutrition (PIVN)-associated chemotherapy (adriamycin, vincristine, VP-16-213, and cyclophosphamide) versus a chemotherapy control group in patients with oat cell lung carcinoma. Thirty-nine evaluable patients were randomized. The test group included 19 patients, whereas 20 were followed in the control group. PIVN was scheduled each day the patient underwent chemotherapy. Each patient received 1,550 kcal day which included 10% glucose, 20% lipids, and amino acids which may or may not have been mixed in the same infusion bottle. The results show ten PIVN patients presently in complete remission at the end of three courses of treatment, compared to nine over the same time period in the chemotherapy control group. Thirty-three percent of patients are still alive after 15 months after the beginning of treatment. There was no significant difference in either general health or side effects, frequency or duration of complete remission, or survival time. After 1 year of treatment, 8 of 19 PIVN patients are still in complete remission, compared to 7 of 20 patients in the control groups.

[Present means to prevent premature birth]

Although overall statistics do not show marked decrease in the percentage of infants with a birth weight under 2,500 g, therapeutical advances of the past few years would allow to conduct an action to prevent prematurity. Namely: beta-stimulating agents can control threatened premature delivery, provided the mothers-to-be, and this is essential, get alarmed without delay and seek prompt advice of their physician, screening and treatment of cervicovaginal infections during pregnancy can undoubtedly be efficient, provided the future mothers are regularly visited from the begining of their pregnancy. But such a prophylaxis necessarily requires, at the various stages of its practice, intelligent cooperation of the pregnant women themselves. Such a cooperation could perhaps be obtained through obstetrical psychoprophylactic interviews as a complement to antenatal consultations, the number of which is too small and the time spent on them too short within the organizational frame of community medicine.