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Results for “causality”

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PubMed1998

A causal model of voluntary turnover among nursing personnel in long-term psychiatric settings.

Causal modeling was used to explore the processes by which individual characteristics, job satisfaction, and intention to quit explain turnover among nursing personnel in 29 Department of Veterans Affairs (VA) long-term psychiatric settings. The sample consisted of 1,106 registered nurses (RNs), licensed practical nurses (LPNs), and nurses' aides. We conceptualized turnover as a multistage process linking social and experiential orientations, attitudes toward the job, the decision to quit, and the behavior of actually quitting. Intention to quit was the strongest direct predictor of turnover. Professional growth opportunities and workload were important indirect predictors of turnover. Dissatisfaction with work hazards and relationships with coworkers were both indirect and direct predictors of turnover. Attitudes towards the job varied by nursing group. LPNs and aides were less satisfied than RNs with autonomy and work hazards. RNs were more dissatisfied with workload. We conclude that strategies to promote retention need to address aspects of jobs tailored to specific nursing groups.

Adult↗

PubMed1981

Clinicians' judgments of female clients' causal attributions.

Presented clinical psychologists (N = 400) with statements of female client attributions for presenting problems with locus of causality varied. Clinicians' judgments of clients were investigated through their evaluations of the accuracy of these attributions. While clinician did not differ in estimate of accuracy based on whether attribution were internal or external, female clinicians were more likely than males to judge client attributions as accurate.

Adult↗

PubMed2001

Heterothallism in Peronospora farinosa f.sp. chenopodii, the causal agent of downy mildew of quinoa (Chenopodium quinoa).

Heterothallism in Peronospora farinosa f.sp. chenopodii, the causal agent of downy mildew of quinoa (Chenopodium quinoa) is reported for the first time. Downy mildew is the most important disease of this crop in the Andean region. Eight single-lesion isolates from different regions in Peru and Bolivia were crossed in all possible combinations using a detached leaf assay, to determine the mating system of the downy mildew pathogen. The presence of two mating types, P1 and P2, was revealed showing that P. farinosa f.sp. chenopodii is heterothallic. It is suggested that frequent sexual reproduction is an important evolutionary force in this pathogen in South America.

Chenopodium quinoa↗

PubMed2026

RNAi in the Rhizarian Phytopathogen Plasmodiophora brassicae: The Causal Agent of Clubroot Disease in Cruciferous Crops.

Although RNA interference (RNAi) is widespread and functionally important across eukaryotes, RNAi pathways are diverse or even lost in some lineages. Rhizaria represents a major and distinct eukaryotic supergroup that includes Plasmodiophora brassicae (Pb), the causal agent of cruciferous clubroot disease, yet RNAi in this lineage remains poorly understood. Here, we characterized an unusual RNAi pathway in Pb. Small RNA sequencing across five representative Pb life stages revealed abundant siRNAs and miRNAs characterized by a predominant 21-nt length, phased genomic distribution, 2-nt 3' overhangs, and a strong 5'-cytidine bias. Three Pb miRNAs were further validated by northern blotting and stem-loop RT-qPCR. Genome analysis identified two canonical AGO homologs, PbAGO1 and PbAGO2, but no Dicer homologs, except for an RNase III-containing Drosha-like protein, PbDRL. Functional analyses showed that PbAGO1 and PbAGO2 mediate gene silencing, whereas PbDRL is required for sRNA biogenesis. Further, the cell wall component chitin was identified from Pb zoosporangia during the early infection and RNAi interfering with its biosynthesis in transgenic plants of Arabidopsis and Brassica napus blocked Pb early infection and conferred broad-spectrum resistance. Our study uncovers an unusual RNAi pathway in Rhizaria and provides a promising strategy to control cruciferous clubroot disease.

Plasmodiophora brassicae↗

PubMedDate not supplied

Variation and causal factors of craniofacial robusticity in Patagonian hunter-gatherers from the late Holocene.

Fueguian-Patagonian skulls have been characterized as some of the most robust of any modern crania. However, the causal factors of such robusticity remain unsettled. We assess within- and among-sample cranial robusticity of seven samples from continental Patagonia and Tierra del Fuego, using geometric morphometric techniques. In addition, the biomechanical, phylogenetic, and climatic hypotheses proposed to account for robusticity in such samples are discussed. Two Amerindian samples of farmers and two early middle Holocene samples from South America were included. The results show: 1) large variation in craniofacial robusticity among Patagonian samples, with the highest robusticity in samples from south continental Patagonia and Isla Grande of Tierra del Fuego, whereas central and north Patagonian samples display the same degree of robusticity as farmer samples; 2) that early middle Holocene samples display lower levels of robusticity than South Patagonian samples; and 3) strong association between latitude and craniofacial robusticity, with the most robust craniofacial morphologies occurring at the highest latitudes. In consequence, neither masticatory stress nor retention of ancestral features is supported by the morphological evidence analyzed. Hence it is hypothesized that endocrine changes related to cold climate may be a plausible explanation for several craniofacial features found in Fueguian and south continental Patagonian samples, such as their large masticatory component, and pronounced supraorbital ridge and glabellar region.

Adaptation, Physiological↗

PubMed1992

The discovery of the causal agent of Minamata disease.

After the outbreak of an epidemic of a strange disease characterized by severe neurological signs in the small Japanese town of Minamata, a number of scientists in different disciplines were required to identify the causal agent. An account is given of the three-year program, with its disappointments and frustrations as a result of the limitations of knowledge of ecological principles and the absence of adequate techniques for detection and measurement. The lessons that have been learned on how toxic compounds can accumulate and concentrate in food chains are described as are the ecological contributions of environmentally safe waste disposal techniques. This article is based on the recollections of Dr. Shoji Kitamura, who contributed greatly to the discovery of the causative agent of Minamata disease.

Animals↗

PubMed1983

Phenotypic heterogeneity in neural tube defects: a clue to causal heterogeneity.

We report here retrospective data on 991 liveborn and stillborn infants with neural tube defects (NTDs) born to Utah residents from January 1, 1940 to December 31, 1979. Data were obtained from multiple sources including approximately 1.25 million vital statistics records and several hundred physician and hospital charts. Causal heterogeneity among NTD patients is presumed because 6% of our cases have other congenital anomalies not part of the NTD field defect. A significant association of NTDs with oral clefts is noted. Sex ratios and empiric recurrence risks for isolated NTDs and NTDs associated with other major malformations are also calculated.

Abnormalities, Multiple↗

PubMed1985

Possible causal heterogeneity in spina bifida cystica.

A study was performed to determine whether causal heterogeneity can be demonstrated among the nonsyndromal spina bifida cysticas based on the vertebral level of the defect. Two groups were compared, probands with defects at or above T 11, likely representing defects of neuralization, and probands with defects at or below T 12, likely defects of canalization. Differences between the two groups were found with respect to reproductive history and occurrence of other malformations. A high degree of concordance for the type of defect among affected sib pairs was also observed. These findings indicate that there is probably heterogeneity within the spina bifida cysticas based on the level of the defect.

Abnormalities, Multiple↗

PubMed1987

Twinning, nonrighthandedness, and fusion malformations: evidence for heritable causal elements held in common.

Certain relatively common congenital malformations that are reported to be excessive in frequency among twins are also found in excess among first-degree relatives of twins. They are familially associated with each other. Like twinning, they are familially associated with nonrighthandedness (NRH). They also share the fact that they affect structures that are built by the fusion of bilateral embryonic halves and then remodeled under the influence of neural crest mesenchyme. This conjunction of associations suggests that twinning, NRH, and the fusion malformations share causal elements, some of which may be heritable. Determination of spatial relationships in embryogenesis ("embryonic body symmetry determination") and the functions of neural crest mesenchyme may be mechanisms unifying these effects.

Diseases in Twins↗

PubMed1994

Ectodermal dysplasias: a clinical classification and a causal review.

We present a casual review of 154 ectodermal dysplasias (EDs) as classified into 11 clinical subgroups. The number of EDs in each subgroup varies from one to 43. The numbers of conditions due to autosomal dominant, autosomal recessive, and X-linked genes are, respectively, 41, 52, and 8. In 53 conditions cause is unknown; 35 of them present some causal (genetic) suggestion.

Chromosome Mapping↗

PubMed2004

Kousseff syndrome: a causally heterogeneous disorder.

The existence of Kousseff syndrome as a distinct entity has been thrown into doubt by a recent study conducted on the family originally reported by Kousseff. In all cases where chromosome 22q11.2 FISH testing has been undertaken, including the original sibship, a chromosome 22q11.2-microdeletion has been identified. We report two cases of sacral myelomeningocele associated with a conotruncal cardiac anomaly or "Kousseff syndrome." The first case, a 4-year-old girl, had a sacral myelomeningocele, tetralogy of Fallot, microcephaly, hydrocephalus, hypoplasia of the corpus callosum and mild-moderate developmental delay. Chromosome 22q11.2 FISH was normal and the facial phenotype was not that of velocardiofacial syndrome. Sequencing of the entire coding region of CITED2 did not reveal a mutation. The second case, a male infant, was found to have a 22q11.2-microdeletion. These cases confirm Kousseff syndrome to be a causally heterogeneous disorder.

Abnormalities, Multiple↗

PubMed1994

Causal link between nucleotide pyrophosphohydrolase overactivity and increased intracellular inorganic pyrophosphate generation demonstrated by transfection of cultured fibroblasts and osteoblasts with plasma cell membrane glycoprotein-1. Relevance to calcium pyrophosphate dihydrate deposition disease.

OBJECTIVE: In subjects with idiopathic calcium pyrophosphate dihydrate (CPPD) deposition disease, cartilage chondrocytes elaborate increased amounts of PPi. The mechanism of the intracellular PPi elevation is not known. Plasma membrane 5'-nucleotide phosphodiesterase I/nucleotide pyrophosphohydrolase (NTPPPH) activity also is elevated in chondrocytes and dermal fibroblasts of patients with idiopathic CPPD deposition disease. NTPPPH, as an ecto-enzyme, could act within certain intracellular compartments. Thus, we hypothesized a potential causal link between increased NTPPPH activity and increased intracellular PPi. METHODS: Transformed simian fibroblasts (COS cells) and human osteoblasts (U2OS cells) were transfected with the 5'-nucleotide phosphodiesterase I ecto-enzyme plasma cell membrane glycoprotein-1 (PC-1), recently shown to be expressed in cartilage, osteoblasts, and fibroblasts. RESULTS: Transfection with PC-1 markedly up-regulated 5'-nucleotode phosphodiesterase I activity and increased intracellular PPi concentrations by increasing the capacity of cells to generate PPi. Importantly, this did not require supplementation with exogenous nucleotides. CONCLUSION: Cellular overexpression of PC-1 produces NTPPPH overactivity and increased intracellular PPi generation in vitro. These findings support the potential importance of NTPPPH overactivity in PPi generation, both inside and outside the cell, in some subjects with CPPD deposition disease.

Animals↗

PubMed1997

Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects.

BACKGROUND: It has become evident that mitral regurgitation (MR) is not uncommon in healthy subjects, and Doppler color flow mapping is a technique that imparts important information relevant to its detection. HYPOTHESIS: Using transthoracic echocardiography, this study evaluated the mechanism of physiologic MR in young normal subjects using transthoracic echocardiography. METHODS: The study population consisted of 48 young normal subjects (mean 21 +/- 5 years) with MR (physiologic MR group), 40 age-matched young normal subjects (mean 20 +/- 5 years) without MR (control group), 45 patients (mean 41 +/- 15 years) with mitral valve prolapse with MR (MVP group), and 27 patients (mean 59 +/- 13 years) with ruptured chordae tendineae (rupture group). RESULTS: Men were predominant in the rupture group, whereas there were no significant gender differences in the other three groups. Left ventricular end-diastolic dimension and left atrial systolic dimension were slightly smaller in the physiologic MR group than in the control group, but were significantly smaller than those in the MVP and rupture groups. The ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography and the ratio of the short- to long-axis diameter of the left ventricular cavity at end diastole, determined from two-dimensional short-axis echocardiogram, were significantly lower in the physiologic MR group than in the other three groups. Mitral regurgitation occurred more frequently at the posteromedial commissural site in the physiologic MR and MVP groups, whereas there was no preference for location in the rupture group. Early systolic MR was often observed in the physiologic MR group, whereas pansystolic MR was common in the MVP and rupture groups. CONCLUSION: As a causal mechanism for physiologic MR detected in young normal subjects, "flattening" of the thorax during growth may cause morphologic abnormalities of the left atrial and ventricular cavities, resulting in spatial imbalance of the mitral complex and resulting in malcoaptation of the valve.

Adult↗

PubMed2006

Causal effects of alcoholism on earnings: estimates from the NLSY.

Propensity score matching is used to investigate the causal relationship between alcoholism and earnings in a young cohort of males and females drawn from the 1989 and 1994 National Longitudinal Survey of Youth (NLSY) in order to investigate productivity losses attributed to alcoholism and to quantify these effects. Results suggest that there are productivity losses attributable to alcoholism; that they become more pronounced over the life cycle; and that they differ between men and women. Ways in which estimates from propensity score matching may or may not improve on instrumental variables estimates are discussed.

Adult↗

PubMed1992

The causal link between human papillomavirus and invasive cervical cancer: a population-based case-control study in Colombia and Spain.

To evaluate the association between human papillomavirus (HPV) and cervical cancer, we performed a population-based case-control study in Columbia and Spain, the former country having an incidence rate of cervical cancer about 8 times higher than the latter. It included 436 cases of histologically confirmed invasive cervical cancer and 387 randomly selected population controls. Information on demographic variables, sexual behaviour and other risk factors was obtained by interview. HPV-DNA was measured in cervical-swab specimens with 3 hybridization assays: ViraPap, Southern hybridization (SH) and polymerase chain reaction (PCR). The presence of HPV-DNA and detection of types 16, 18, 31, 33 and 35 were strongly associated with cervical cancer in each country regardless of the assay used. For both countries combined the adjusted odds ratios and 95% confidence intervals were: ViraPap OR = 25.9 (10.0-66.7); SH OR = 6.8 (3.4-13.4); and PCR OR = 28.8 (15.7-52.6). HPV-16 was the most common type detected in both cases and controls. Our results indicate that there is a very strong association between HPV 16, 18, 31, 33 and 35 and invasive cervical cancer and that this association is probably causal.

Carcinoma, Squamous Cell↗

PubMed2002

Hepatitis B vaccination: risk-benefit profile and the role of systematic reviews in the assessment of causality of adverse events following immunisation.

Since the early 1990s, several cases of demyelinating diseases were reported in France in association with the vaccination against hepatitis B. A large scientific, regulatory, and public debate took place to reassure the growing concern of the population. The objective of this paper is to examine the decision process undertaken both in France and in Italy; to outline the main findings of the studies conducted before and after the French decision to suspend the vaccination campaign among adolescents; and to describe the contribution of systematic review and causality criteria in the evaluation of the risk-benefit profile of vaccines. Even on the basis of the early findings, which appeared to be compatible with a low increase in the risk associated with the vaccination, it was apparent that the risk-benefit profile was unchanged for newborns, and was essentially unchanged for adolescents and for high-risk adults. The availability of subsequent negative association studies provided further reassurance. It is essential to rely on well-conducted systematic reviews to produce valid and reliable estimates of the risk-benefit profile.

France↗

PubMed2003

Compliance with a pelvic muscle exercise program as a causal predictor of urinary stress incontinence amongst Chinese women.

AIM: To determine the importance and contribution of compliance in a pelvic muscle exercise program as a factor in reducing the severity of urinary stress incontinence amongst Chinese women. METHODS: Two hundred fourteen women presenting with urinary stress incontinence who agreed to undertake a program of pelvic muscle exercises were recruited into the study. Incontinence (wetting episodes), pelvic muscle strength, exercises compliance, correctness of pelvic muscle exercise technique, duration of stress incontinence, and previous history of pelvic surgery were recorded on four occasions: baseline (first clinic session) and second to fourth clinic sessions. Demographic data were also collected at baseline. Stepwise multiple regression analyses were used to determine the relative importance of compliance to exercise regime in predicting the severity of incontinence. Path analysis was used to provide a summary description of the influence of compliance on the outcomes over the four visits. RESULTS: The pelvic muscle training program appears to be able to reduce the overall urinary incontinence episodes by 85.2% and achieved a 73.1% increase in pelvic muscle strength. Although the number of wetting episodes in any visit are causally linked to that recorded in previous visit, those who were more compliant had a greater reduction. Age, mode of delivery, menopausal status, history of pelvic surgery, and duration of incontinence did not appear to contribute significantly to predicting incontinence. CONCLUSION: Compliance with pelvic muscle exercises significantly contributed to a reduction in urinary stress incontinence.

Adult↗

PubMed2005

Test of the health promotion model as a causal model of commitment to a plan for exercise among Korean adults with chronic disease.

The purpose of this study was to test seven constructs (prior experience of exercise, perceived health status, exercise benefits, exercise barriers, exercise self-efficacy, social support for exercise, and options for exercise) from the health promotion model (HPM) as a causal model of commitment to a plan for exercise in a sample of 400 Korean adults with chronic disease. Using structural equation modeling (SEM), we found that all fit indices indicated a good fit. The final model accounted for 54% of the variance in commitment to a plan for exercise. Prior experience with exercise and exercise benefits were the factors most highly related. Health professionals can assess prior experience and emphasize personally relevant benefits of exercise in designing intervention programs to help Korean adults with chronic disease become more physically active.

Chronic Disease↗