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PubMed1993

[A chapter in systematic schizophrenia research--the search for causal explanations for sex differences in age of onset].

With the aim of detecting causal processes contributing to the onset of schizophrenic symptoms a systematic search strategy was worked out. One of the few epidemiological findings on schizophrenia consistently diverging from expected values, the sex difference in age at first admission, was taken as a basis and replicated on data from the Danish and the Mannheim case registers by controlling for selection and diagnostic artefacts. Danish psychiatrists turned out to have underdiagnosed schizophrenia to a considerable extent at least in 1976, the year from which the analysed case-register data dated. After the exclusion of alternative explanations, the time when symptoms appeared for the first time and the first acute episode occurred was determined for a representative sample of 267 first-admitted cases with a diagnosis of non-affective functional disorder by using the IRAOS interview designed for this purpose. At any of the definitions of first onset applied the mean age of females was significantly higher than that of males, the difference ranging from 3.2 to 4.1 years. The distribution of onsets across the female life cycle showed a clearly delayed increase at young age and a second, lower peak of onsets at the age of 45-54, whereas the cumulative incidence up to the age of 60 years was equal for males and females. On assessing the plausibility of psychosocial versus biological explanations it was hypothesized that due to the effect of estrogens the vulnerability threshold for schizophrenia is raised in females until the menopause. Animal experiments and postmortem analysis showed that chronic estrogen applications significantly shortened dopamine-induced behaviour and reduced D2 receptor sensitivity in the brain. The applicability of this pathophysiological mechanism on human schizophrenia was tested on acutely schizophrenic females with normal menstrual cycles. A significant negative correlation was found between measures of symptomatology and plasma estrogen levels. Apparently, the manifestation of schizophrenic symptoms is influenced by a sufficiently sensitive D2 receptor system in the brain, blocked by neuroleptics and modulated by estrogens.

Adolescent↗
PubMed1993

Age differences in understanding of disease causality: AIDS, colds, and cancer.

The development of concepts of disease causality was explored by asking 9-, 11-, and 13-year-olds and college students about risk factors for AIDS, colds, and cancer. Their knowledge became more accurate and differentiated with age. Although younger children knew a good deal about what causes each of the diseases, they lacked knowledge of what does not cause them, often inferring that risk factors for one disease, especially AIDS, cause other diseases as well. Knowledge of true risk factors for a disease was largely independent of knowledge of non-risk factors, and knowledge of one disease was largely independent of knowledge of another. These findings provide clues as to how disease understandings evolve with age and suggest that health educators must both understand students' current knowledge structures and explicitly teach students to make important differentiations between risk and non-risk factors for a given disease and between distinct diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Posttraumatic limb swelling and joint stiffness are not causally related experimental observations in rabbits.

Periarticular and intraarticular fractures frequently cause limb swelling and joint stiffness. The two effects are widely assumed to be related--an assumption long held but never tested. Over a ten-year period, a rabbit hind limb model was developed and tested to ascertain methods of preventing or reducing limb swelling and joint stiffness after a local skeletal injury. Limb swelling was monitored for the three- to four-week duration of the studies by volume displacement, and joint stiffness was determined arthrographically. Mechanical treatment modalities tested included limb pressurization, passive motion of varying duration (from four to 24 hours daily), creation of an intraarticular hematoma, and creation of dependent edema. Chemical modalities tested included systemic and intraarticular steroids, intramuscular and oral nonsteroidal antiinflammatory drugs, topical dimethyl sulfoxide, two antihistamine drugs, and two diuretics. At statistically significant levels, all of the modalities tested affected swelling or stiffness, but only terfenadine, an antihistamine, affected both. Treatment with terfenadine resulted in decreased stiffness but increased swelling. When reviewing the results of all of the treatment modalities in concert, it is apparent that, in this model, limb swelling and joint stiffness after injury are not causally related. The significance of this work in forthcoming clinical trials for treatment of posttraumatic joint stiffness are noteworthy.

Animals↗
PubMedDate not supplied

Causal evaluation of impact of support workshop for HIV+ men.

A program logic model was used to design and evaluate a support workshop for men infected with HIV. The model identified three proximal outcomes leading to the ultimate goal of motivating participants to initiate ongoing support relationships. Path analysis was used to evaluate the workshop. The findings indicated the most important motivator to initiating ongoing support was the awareness among participants of the need to talk about their HIV status and risk of transmission and their feeling capable to do so. The proximal outcomes which contributed to this impact were: recognition of their own needs from listening to testimonials by others, developing awareness and skills by engaging in role plays, and learning options for discussion by participating in a sexual issues group. The workshop findings demonstrated the benefits of developing a pre-program logic model and using causal evaluation to understand factors determining impact.

Adaptation, Psychological↗
PubMed1993

[Ecology and causality--on the reliability of environmental medicine knowledge].

In principle, environmental medicine has two responsibilities. On the one hand this special field is required to provide a practicable and enlightening medicine for people seeking help. On the other hand environmental medicine as an ecological medicine" is required to analyse the truth content in science and the reliability of scientific knowledge with regard to environmental processes. For not only direct-acting toxicities of environmental chemicals but also the imbalance in ecological systems possess pathogenic potencies. Do these ecological processes in systems actually have the demanded obvious causality?

Disease↗
PubMed1995

Vibrio cholerae non-O1 as a causal pathogen in cholera patients in Yangon, Myanmar.

Vibrio cholerae non-O1 was studied in patients with rice watery diarrhoea admitted to the Infectious Diseases Hospital, Yangon. The study was conducted during 1993-1994 to determine the association of the pathogen with the disease. Altogether 771 rectal swabs were collected and examined. V. cholerae were isolated by the standard methods. The seasonal, age and sex distribution, serotyping and susceptibility of these isolates to antibiotics were investigated, V. cholerae were isolated from 233 (3O.2%) samples. Among them, V. cholerae O1 were isolated from 117 (5O%) samples and V. cholerae non-O1 from 116 (5O%) samples. The seasonal, age and sex distribution was identical in both V. cholerae O1 and V. cholerae non-O1 groups. V. cholerae O139 was isolated during February 1994. Thus V. cholerae non-O1 was also one of the causal pathogens of cholera, like V. cholerae O1 in this community.

Adolescent↗
PubMed1995

[Psychosocial causal attributions by myasthenia gravis patients. A longitudinal study of the significance of subjective illness theories after diagnosis and in follow-up].

The present study evaluates the impact of subjective theories of illness in patients suffering from Myasthenia gravis. 46 inpatients were examined after the diagnosis had been made (T1) and 6 months later (T2). The following instruments have been used: a semistructured interview, the ¿Freiburg Personality Inventory¿ (FPI), the ¿Freiburg Questionnaire of Coping with Illness (FKV) and a questionnaire for the judgement of body experiences (FBK). Ratings concerning neurotic symptoms (PSKB), mechanisms of defence (KBAM) and the doctor-patient-relationship were made by the interviewers and the treating neurologist as well. 35% of the patients experienced a connection between psychosocial factors (stress) and the onset of the disease. As compared with those patients not showing a psychosocial causal attribution there are no differences in somatic (type and severity of the disease, thymus histology), but in psychological variables. Patients attributing their disease to psychosocial factors prove to be more depressive, insecure and excitable at T1. They are more likely to be women. These findings are in accordance with the results of previous studies. However, 6 months later (T2) there is some evidence of a psychological stabilization of those patients using psychosocial attributions, as different instruments show concurrently. Partially they appear now even less depressive. This result is understood as a hint for the significance of emotional factors for the process of coping with the disease: patients using a psychosocial explanation concept may appear more vulnerable at an early stage of the disease. But perhaps, by this more emotionally centered coping process, they can reach stability which is connected with the construction of a psychosocial theory of the disease.

Adaptation, Psychological↗
PubMed1995

Vascular malformations associated with other congenital anomalies of the central nervous system: coexistence and possible causal relations.

Two cases of vascular malformations coexisting with other congenital defects of the central nervous system (CNS) are presented here. The first patient was a 14-year-old girl mentally retarded who demonstrated seizures and balance disturbances with onset in early infancy. The neuropathological examination revealed vascular malformations in the pons, diastematomyelia (triple central canal) in the sacral spinal cord and palleocerebellar granular layer dysplasia. The second patient was a 10-year-old boy hospitalized because of purulent dermatitis who suddenly developed recurrent generalized and focal motor seizures. The neuropathological examination disclosed multiple capillary teleangiectases with focal anomalies within cerebral cortex of the frontal and parietal lobes. The relations between several developmental anomalies in the CNS and possible causal relation between such malformations are discussed.

Abnormalities, Multiple↗
PubMed1995

[Deficiency of human ciliary neurotropic factor (CNTF) is not causally related to amyotrophic lateral sclerosis (ALS)].

Ciliary neurotrophic factor (CNTF) promotes the survival of motor neurons in vitro and in vivo. A recent report showed that disruption of the CNTF gene in mice caused motor neuron degeneration. We have found a null mutation in the human CNTF gene. The mutated allele shows a G to A transition producing a new splice acceptor site and the resulting mRNA species codes for an aberrant protein. Analysis of tissue samples demonstrated that the mutated allele expressed only the mutated mRNA species. In 391 Japanese people tested, 61.9% were normal homozygotes, 35.8% heterozygotes and 2.3% mutant homozygotes. The distribution of the three genotypes is similar in healthy and neurological disease subjects including ALS patients. Our findings indicate that CNTF deficiency is not causally related to ALS.

Alleles↗
PubMed1996

[A prospective study on causal factors of female infertility with laparoscopy and transvaginal B-ultrasound].

OBJECTIVE: To study the casual factors of female infertility with laparoscopy and B-ultrasound. METHODS: Eighty-five infertile women were evaluated by serial transvaginal B-ultrasound scans for follicular development and ovulation and by laparoscopic examinations 2 to 6 days after ovulation. RESULTS: The patterns of follicular development and ovulation detected by B-ultrasound were: (1) ovulation from normal follicle (ONF) (56.47%); (2) ovulation from two follicles at the same time (O2F) (5.88%); (3) ovulation from small follicle (OSF) (16.47%); (4) ovulation from polycystic ovaries (PCO) (3.53%); (5) luteinized unruptured follicle syndrome (LUFS) (7.06%); (6) anovulation (10.90%). Laparoscopic examinations showed that the incidence of partial and complete tubal obstruction was 32.94% and pelvic adhesions 35.29%. Pelvic tuberculosis was found in 20.00%, which was the main disease leading to pelvic adhesions (46.67%), and tubal obstruction (60.71%). Endometriosis (EMS) was discovered in 36 cases (42.35%), among them, 30 (83.33%) had patent tubes. The stigmas or/and corpus hemorrhagica were seen in 60 out of 70 patients in whom ovulation had been diagnosed by B-ultrasound. 6 cases were defined as "mechanically unruptured follicle syndrome". CONCLUSIONS: Abnormal follicular development may result in female infertility. Pelvic tuberculosis is another main causal factor of infertility. Endometriosis related infertility may rather result from other factors than tubal obstruction. Laparoscopic examinations combined with transvaginal B-ultrasound scans are very useful approaches in the etiological study of female infertility.

Adult↗
PubMed1997

[Causal relationship between GBV-C and fulminant hepatitis].

GBV-C is recently discovered RNA virus which appeared to be member of Flaviviridae. We previously reported the possible involvement of GBV-C in the etiology of fulminant hepatitis(FH). It is still controversial whether GBV-C cause FH. So far, the only reliable tool for the diagnosis of GBV-C is the detection of the viral genome using PCR. Detection of GBV-C in serum of patient with FH dose not necessarily mean that GBV-C is causal virus. Serial quantification of serum GBV-C RNA in patient with FH may reveal a pathogenetic role of GBV-C. Further study is needed to elucidate the relationship between FH and a specific strain of GBV-C.

Base Sequence↗
PubMed1997

[Leptin and its biological and clinical significance. Is leptin and insulin resistance in the X-5H hormonal metabolic syndrome a parallel or causally-linked phenomenon?].

Leptin 167 an amino acid product of the recently discovered obesity gene "ob-gene", is a tissue hormone of adipose tissue. It is a hormonal satiety signal or a signal for terminating food intake. Its level rise after a meal or after administration. Rats with a mutation of the ob-gene have zero or very low leptin levels, are hyperphagic, obese and sterile, develop diabetes as a result of overeating. Administration of recombinant leptin arrests hyperphagia, the body weight declines and sexual function improve partly, in particular in males. It seems that leptin controls not only the function of the hypothalamic satiety centre but also the output of GnRh and other liberins as well as thermoregulation, muscular and sexual activity and thus energy expenditure. In the majority of obese rats and human the leptin levels are significantly higher compared with asthenic individuals, proportionate to the percentage of body fat and BMI. Obesity promotes also insulin resistance and penetration of the H-phenomenon into the phenotype. In the insulin resistance syndrome (5H-X) it may thus be assumed that there is a parallel leptin and insulin resistance, probably of the postreceptor type, and even a causal association, as the "db" gene is identical with the gene for leptin receptors.

Animals↗
PubMed1998

Autoimmune thyrotoxicosis developed during growth hormone (GH) treatment of an adult with childhood onset GH-deficiency. A causal relationship?

Thyroid hyperfunction during growth hormone (GH) therapy has not been reported previously. We report a case of a 33-year-old female who developed autoimmune thyrotoxicosis during treatment with GH and with normalization of the thyroid function after discontinuation of GH therapy. After rechallenge with GH she again developed thyrotoxicosis, this time with presence of thyroid autoantibodies and without normalization of the thyroid function after stopping the GH treatment. Several possibilities for a causal relationship between GH therapy and development of autoimmune thyrotoxicosis are proposed.

Adult↗
PubMed1998

Maternal education and child health: is there a strong causal relationship?

Using data from the first round of Demographic and Health Surveys for 22 developing countries, we examine the effect of maternal education on three markers of child health: infant mortality, children's height-for-age, and immunization status. In contrast to other studies, we argue that although there is a strong correlation between maternal education and markers of child health, a causal relationship is far from established. Education acts as a proxy for the socioeconomic status of the family and geographic area of residence. Introducing controls for husband's education and access to piped water and toilet attenuate the impact of maternal education on infant mortality and children's height-for-age. This effect is further reduced by controlling for area of residence through the use of fixed-effects models. In the final model, maternal education has a statistically significant impact on infant mortality and height-for-age in only a handful of countries. In contrast, maternal education remains statistically significant for children's immunization status in about one-half of the countries even after individual-level and community-level controls are introduced.

Child Welfare↗
PubMedDate not supplied

[Safety assessment of a Brazilian company based on analysis of work accidents by the causal tree method].

We present here the results of a study of 21 work-related accidents that occurred in a Brazilian manufacturing company. The aim was to assess the safety level of the company to improve its work accident prevention policy. In the last 6 months of 1992 and 1993, all accidents resulting in 15 days' absence from work, reported for social security purposes, were analyzed using the INRS causal tree method (ADC) and a questionnaire completed on site. Potential risk factors for accidents were identified based on the specific factors highlighted by the ADC. More universal trees were also compiled for the safety assessment. Three hundred and thirty specific accident factors were recorded (mean of 15.71 per accident). This is consistent with there being multiple causes of accidents rather than the assertion of Brazilian business safety departments that accidents are due to "dangerous" or "unsafe" behavior. Introducing the idea of culpability into accidents prevents the implementation of an appropriate information feedback process, essential for effective prevention. However, the large number of accidents related to "material" (78%) and "environment" (70%) indicates that working conditions are poor. This shows that the technical risks, mostly due to unsafe machinery and equipment are not being dealt with. Seventy-five potential accident factors were identified. Of these, 35% were "organizational", a high proportion for the company studied. Improvisation occurs at all levels, particularly at the organizational level. This is thus a major determinant for entire series of, if not most, accident situations. The poor condition of equipment also plays a major role in accidents. The effects of poor equipment on safety exacerbate the organizational shortcomings. The company's safety intervention policy should improve the management of human resources (rules designating particular workers for particular workstations; instructions for the safe operation of machines and equipment; training of operators, etc.) and introduce programs to detect risks and to improve the safety of machines and equipment. We also recommend the establishment of a program to follow the results of any preventive measures adopted.

Accidents, Occupational↗
PubMed1998

[Hereditary diseases with tooth anomalies and their causal genes].

In this review, we describe the current knowledge and the advances in research on human genes whose defect leads to dental anomalies. Recently, it was demonstrated that a missense mutation of a human homeobox MSX1 gene causes autosomal dominant agenesis of second premolars and third molars. X-linked anhidrotic ectodermal dysplasia (EDA), characterized by abnormal hair, teeth, and sweat glands, was demonstrated to be caused by a mutation in a novel transmembrane protein gene that is expressed in epithelial cells and in other adult and fetal tissues. The autosomal dominant Rieger syndrome (RS) manifests hypodontia, adontia, iridogoniodysgenesis and umbilical anomalies. Recently, a novel homeobox gene, RIEG, of Otx family was cloned as a causal gene of RS. The several mutations have been reported on the genes causing hypophosphatasia, which is characterized by defective mineralization of the skeletal and dental structures. An autosomal dominant dentinogenesis imperfecta (DI) is mostly associated with osteogenesis imperfecta (OI). Most patients with DI have mutations in either the COL1A1 or COL1A2 genes of type I collagen. Amelogenesis imperfecta (AI) is a diverse group of hereditary disorders characterized by a variety of developmental enamel defects including hypoplasia and hypomineralization, some of which have been revealed to be associated with defective amelogenin genes.

Alkaline Phosphatase↗
PubMed1999

Role of a stimulus filling an action-outcome delay in human judgments of causal effectiveness.

Experiments examined the effect of a stimulus filling a response-outcome delay on human judgments of causal effectiveness. In Experiment 1, subjects rated the effectiveness of 2 concurrently available responses. One response led to the outcome with a 75% probability, the other never led to the outcome. Ratings were higher for the former compared to the latter key, and for immediate compared to delayed outcomes. A signal presented during the delay ameliorated this deficit. Experiments 2 and 3 examined conditioned reinforcement and perceptual catalysis accounts of this effect. In both experiments, 50% of responses on each of 2 keys led to an outcome. Ratings were high, relative to an unsignaled condition, when a stimulus filled the outcome delay, and when the same stimulus followed the response but did not precede the outcome. This result is not consistent with the operation of perceptual catalysis and was shown to be the result of secondary-reinforcement-like processes rather than outcome-confusion or generalization between responses (Experiments 3, 4).

Adolescent↗