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Biomedical subjects

C A Jackson

Publications and source records attributed to C A Jackson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Characteristics and service use of seriously mentally ill persons living in rural areas.

OBJECTIVE: Data from a cross-sectional survey of 210 current or former inpatients at Mississippi State Hospital and 197 informants, usually patients' family members, were used to compare the demographic, clinical, and service use characteristics of patients living in rural areas with those of patients living in nonrural areas. METHODS: All subjects completed structured face-to-face interviews. Information on recent use of community mental health center (CMHC) services was obtained from CMHC records. Characteristics of rural patients (N = 107) and nonrural patients (N = 103) were compared using chi square and t tests. RESULTS: Rural patients were less likely to have completed high school and more likely to be living with family members. Although rural and nonrural subjects were clinically similar, rural subjects were less likely to have received certain community mental health services such as case management and day treatment and were more likely to have used physical health services and to have been involved with the criminal justice system. CONCLUSIONS: Differences between rural and nonrural patients in patterns of service use are most likely a reflection of less availability or accessibility of mental health services in rural areas, resulting in spillover into physical health and criminal justice sectors. Rural community mental health centers need to formally incorporate families, local medical providers, and law enforcement officials into their network of care.

Activities of Daily Living↗
PubMed1995

Cloning, expression and sequence analysis of the genes encoding the heterodimeric methylmalonyl-CoA mutase of Porphyromonas gingivalis W50.

Two genes that encode methylmalonyl-CoA mutase (MCM) have been characterised in Porphyromonas gingivalis W50 (Pg). The genes, designated mcmA and mcmB are transcribed in an operon and encode the MCM small subunit (SS, 68,626 Da) and the MCM large subunit (LS, 78,703 Da), respectively. A recombinant Escherichia coli (Ec) clone harbouring the Pg mcmA and mcmB genes expressed MCM activity 280-times higher than that of the Ec control. The C terminus of the MCM LS has sequence homology to domains of a variety of enzymes that consume or produce methylmalonyl-CoA, suggesting that the MCM LS C-terminal domain is involved in substrate binding. The MCM LS C-terminal region also exhibits homology to other enzymes that have cobalamin-containing cofactors. It is likely, therefore, that the C terminus of the MCM LS is an important MCM domain involved in both substrate and cofactor binding.

Amino Acid Sequence↗
PubMed1995

Endothelial lipopigment as an indicator of alpha-tocopherol deficiency in two equine neurodegenerative diseases.

Two spontaneous neurodegenerative diseases of the horse, equine motor neuron disease (EMND) and equine degenerative myeloencephalopathy (EDM), have been associated with alpha-tocopherol deficiency, and both were characterized by prominent accumulations of endothelial lipopigment in the small vessels of the spinal cord. These endothelial pigment deposits appear to be reversible. In EMND horses pasture-supplemented for 9 months or more after the progression of weakness and wasting had arrested, there was very little endothelial lipopigment. The origin and the potential effects of these endothelial lipopigment accumulations are discussed.

Animals↗
PubMed1995

Estimating eye care workforce supply and requirements.

PURPOSE: To estimate the workforce supply and requirements for eye care in the United States. METHODS: Three models were constructed for analysis: supply of providers, public health need for eye care, and demand (utilization) for eye care. Ophthalmologists, other physicians, and optometrists were included in the models. Public health need was determined by applying condition-specific prevalence and incidence rates from population-based and other epidemiologic studies. Demand was determined by use of national databases, such as the National Ambulatory Care Survey, National Hospital Discharge Survey, and Medicare Part B. Time requirements for care were obtained through a stratified sample survey of the membership of the American Academy of Ophthalmology. RESULTS: Under modeling assumptions that use a work-time ratio of one between optometrists and ophthalmologists and between specialist and generalist ophthalmologists, a significant excess of eye care providers exists relative to both public health need and demand. Changes in the work-time ratio, work-hours per year per provider, care patterns for the same condition, or other factors could significantly reduce or eliminate the surplus relative to need. CONCLUSION: If optometrists are the preferred primary eye care provider, ophthalmologists would be in excess under all demand scenarios and all need scenarios where the optometrist to ophthalmologist work-time ratio is greater than 0.6. No excess of ophthalmologists would exist if ophthalmologists are the preferred primary eye care provider. Data on the appropriate work time ratio will help refine estimates of the imbalance between supply and requirements.

Eye Diseases↗
PubMed1995

Incidence and risk factors of equine motor neuron disease: an ambidirectional study.

We have conducted an ambidirectional study to estimate the incidence of equine motor neuron disease (EMND) in the northeastern US. The clinical and pathological features of EMND are similar to those described in human motor neuron disease. We have also collected data on all EMND cases reported in the US and described the geographic distribution of the disease. To identify factors associated with the risk of EMND, the authors assembled 163 control horses from the population in which cases were identified. The significance of association between the hypothesized factors and the risk of EMND was evaluated using the logistic regression analysis and the risk was estimated using the odds ratio. Seventy-eight horses in North America were diagnosed with EMND between the period of January 1985 and November 1993. Most of the cases were identified in the Northeast of the US and the incidence of EMND appears to be increasing in this area. Factors found to be significantly associated with EMND were breed and the age of the horse. Quarter horses were the only breed with a significantly higher risk of EMND (odds ratio = 2.3). The risk of EMND increased with age, reached a peak around 16 years of age and then declined. The sex of the horse was not associated with the risk of the disease.

Age Distribution↗
PubMed1995

Mental health care utilization in prepaid and fee-for-service plans among depressed patients in the Medical Outcomes Study.

OBJECTIVE: We compare mental health utilization in prepaid and fee-for-service plans and analyze selection biases. DATA SOURCE: Primary data were collected every six months over a two-year interval for a panel of depressed patients participating in the Medical Outcomes Study, an observational study of adults in competing systems of care in three urban areas (Boston, Chicago, and Los Angeles). STUDY DESIGN: Patients visiting a participating clinician at baseline were screened for depression, followed by a telephone interview, which included the depression section of the NIMH Diagnostic Interview Schedule. Patients with current or past lifetime depressive disorder and those with depressed mood and three other lifetime symptoms were eligible for this analysis. We analyze mental health utilization based on periodic patient self-report. ANALYTIC METHODS: We use two-part models because of the presence of both nonuse and skewness of use. Standard errors are corrected nonparametrically for correlations across observations due to clustered sampling within participating physicians and repeated observations on the same individual. PRINCIPAL FINDINGS: The average number of mental health visits was 35-40 percent lower in the prepaid system, adjusted and unadjusted for observed differences in patient characteristics, including health status. Utilization differences were concentrated among patients of psychiatrists, with only minor differences among patients of general medical providers. Analyzing the effect of switches that patients make between payment systems over time, we found some evidence of adverse selection into fee-for-service plans based on baseline utilization, but not based on utilization at the end of the study. In particular, after adjusting for observed patient characteristics and health status, patients switching out of prepaid plans had higher baseline use than predicted, whereas patients switching out of fee-for-service had lower use than predicted. Switching itself appears to be related to an immediate decline in utilization and was not followed by an increase or "catch-up" effect. CONCLUSIONS: The absence of the commonly found "catch-up" effect following switching and the significant decrease in utilization during the switching period suggests an interruption in care that does not occur for patients staying within a payment system. This finding emphasizes the need for integrating new patients quickly into a system, an issue that should not be neglected in the current policy discussion.

Boston↗
PubMed1995

Impact of prior and current alcohol use on use of services by patients with depression and chronic medical illnesses.

OBJECTIVE: Alcohol use often co-occurs with other major chronic conditions, but its effect on health care utilization in this context is not understood. This study examines the impact of alcohol consumption on health care use by patients with chronic medical conditions or depression, or both. DATA SOURCES/STUDY SETTING: Data came from the Medical Outcomes Study, an observational study of patients from the offices of general medical providers and mental health specialists in three U.S. cities. STUDY DESIGN: Longitudinal data spanning four years for outpatient general medical visits and outpatient mental health visits were analyzed using a two-part model to assess the impact of alcohol use disorder, problem drinking, and current and past alcohol consumption on health care use by patients, controlling for patient demographics and health status. DATA COLLECTION/EXTRACTION METHODS: Data were collected from 2,546 adult patients with hypertension, diabetes, heart disease (congestive heart failure or myocardial infarction), and/or current major depression or subthreshold depression using periodic, self-report surveys detailing health care utilization and health status information. PRINCIPAL FINDINGS: Current alcohol consumption increases outpatient doctor visits, and problems related to current drinking decrease outpatient mental health visits. CONCLUSIONS: Patterns of alcohol consumption have an impact on both mental health and overall health care use by patients with chronic medical conditions or depression.

Adult↗
PubMed1994

Neurological manifestation of cholesterinic granulomas in three horses.

Cholesterinic granulomas have been previously reported as an incidental post mortem in horses. Three adult horses with diencephalic dysfunction due to cholesterinic granulomas are described. All the horses exhibited profound depression, somnolence and reluctance to move. One horse experienced generalised seizures. Cerebrosinal fluid was xanthochromic with an elevated total protein in two of the cases evaluated. The large cholesterinic granulomas caused expansion of the lateral ventricle and secondary hydrocephalus due to the build up of cerebrospinal fluid behind the mass. Cholesterinic granulomas are believed to result from choroid plexus congestion and haemorrhage.

Animals↗
PubMed1994

Resting Tl-201 scintigraphy in the evaluation of coronary artery disease in children with Hurler syndrome.

Severe coronary artery disease may occur early in the course of mucopolysaccharidosis. The authors present radiologic, scintigraphic, and pathologic findings in five patients with Hurler syndrome. Thallium-201 myocardial scintigraphy and selective coronary angiography obtained within 2 days to 6 months were correlated in five patients. Postmortem examination of the coronary arteries was obtained in one patient within hours of angiography. Interobserver agreement on grading of scintigraphic abnormalities was poor. Nonspecific findings on Tl-201 studies included septal abnormalities in all five patients. Scintigraphic findings were corroborated by angiography and postmortem results in only 3 of 5 patients. Our findings suggest that resting Tl-201 scintigraphy has limited value in the detection of coronary artery disease in patients with Hurler syndrome.

Child, Preschool↗
PubMed1994

Equine motor neuron disease: findings in 28 horses and proposal of a pathophysiological mechanism for the disease.

Over a three and one-half year period, 28 adult horses were diagnosed with equine motor neuron disease (EMND). The most commonly identified environmental risk factors for a horse having EMND were absence of grazing for more than a year and provision of poor quality hay. Quarter Horses were 5.4 times more at risk than other breeds but this was thought to be an epiphenomenon related to the frequency of Quarter Horses at boarding stables. Weight loss, excessive recumbency and/or trembling were the first signs noted. Other clinical diagnostic signs included: constant shifting of the weight in the rear limbs, abnormally low head carriage and muscle fasciculations. Excellent to ravenous appetites were present in all cases and marked coprophagia in some cases. Abnormally high serum concentration of muscle-derived enzymes was the only consistent serum chemistry abnormality found. Abnormal glucose absorption, increased cerebrospinal fluid total protein and intrathecal production of IgG were identified in a number of cases. Euthanasia was performed on 5 horses within 4 days of hospital admission, because of inability to stand or respiratory distress, and on 18 horses after the diagnosis had been completed. Five affected horses were maintained for observational purposes for periods of 9 months to over 2 years after the onset of clinical signs. They were given access to pasture and 2 were given supplemental vitamin E as the only therapy. Marked clinical improvement occurred in the 4 more acutely affected horses. Pathological findings, preference of type 1 muscle fibre atrophy and lipopigment accumulation within the capillary endothelium of the spinal cord of all cases, supported the hypothesis of EMND being an oxidative disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Renal alpha-adrenergic receptors and genetic hypertension.

The hypothesis has been proposed that an increase in the number of renal alpha-adrenergic receptors may contribute to the pathogenesis of genetic hypertension. Herein we review recent findings regarding expression of renal alpha 1 (alpha 1a, alpha 1b)- and alpha 2 (alpha 2a, alpha 2b)-adrenergic subtypes and we provide an updated revision of the above-stated hypothesis. Enhancement in receptor number or in post-receptor components responsible for alpha 1- and alpha 2-adrenergic-mediated sodium reabsorption in proximal tubule may contribute to sodium retention and an elevation in blood pressure. Perhaps such changes contribute to the increase in blood pressure in genetically determined hypertension in humans, although direct tests of this notion have not yet been performed.

Animals↗
PubMed1993

The structure of economic incentives in the Robert Wood Johnson/HUD Program on Chronic Mental Illness 1988.

This paper describes the financial arrangements put into place by cities participating in the Robert Wood Johnson Foundation's Program on Chronic Mental Illness. Descriptive information is given on the level of expenditure, the mix of revenues, and the terms under which local, federal, and Medicaid dollars are allocated to local programs. Data are presented on the use of state hospitals and the number of severely mentally ill individuals in treatment. These data are used to make observations on the initial stages of the demonstration.

Chronic Disease↗
PubMed1992

A comparison of the relationships of the glucose tolerance test and the glycated haemoglobin assay with diabetic vascular disease in the community. The Islington Diabetes Survey.

We have compared the relationships of fasting and 2 h blood-glucose during a 75 g oral glucose tolerance test, and those of an affinity chromatography assay of glycated haemoglobin, with the presence of vascular complications of diabetes mellitus in 223 subjects without known diabetes aged over 40 years selected from a community screening study population. The subjects included 15 (6.9%) with newly diagnosed diabetes and 52 (24.1%) with impaired glucose tolerance. Employing receiver operating characteristic analysis, the tests were similar in their relationship with three cases of retinopathy, 19 of microalbuminuria and six of peripheral neuropathy. The prevalence of coronary heart disease, defined as angina, myocardial infarction, or electrocardiographic changes of ischaemia, increased linearly across all four quartiles of both 2 h blood glucose and glycated haemoglobin concentration, but using logistic regression analysis, 2 h blood glucose was a better predictor of coronary heart disease than glycated haemoglobin. Receiver operating characteristic analysis also showed that 2 h blood glucose generally performed better than any of four assays of glycated haemoglobin in classifying those subjects with coronary heart disease.

Aged↗
PubMed1992

Expression of renal alpha 1-adrenergic receptor subtypes in established hypertension.

Radioligand binding studies were undertaken in renal membranes of normotensive and hypertensive rats in order to test the hypothesis that there are alterations in renal alpha 1-adrenergic subtypes of genetic hypertensive animals. The highly selective competitive compound, (+)-niguldipine, was used to distinguish high-affinity (alpha 1a) from low-affinity (alpha 1b) sites, after initial studies demonstrated that this compound had greater selectivity than 5-methylurapidil in distinguishing alpha 1a and alpha 1b sites in rat renal membranes. In contrast to the significant difference in the blood pressure of the spontaneously hypertensive rats (delta BP = 74 mm Hg), there was no difference in the renal alpha 1-adrenergic receptor density. Membranes from the whole kidneys of spontaneously hypertensive rats (SHRs) possessed 31% alpha 1a and 69% alpha 1b sites with -log(Ki) values of 10.0 +/- 0.3 and 7.1 +/- 0.1, respectively, for (+)-niguldipine. However, these values were not different from those obtained from renal membranes of the normotensive Wistar-Kyoto (WKY) rats. These results indicate that in spite of the elevated blood pressure during the established phase of hypertension, the number, the affinity, and the ratio of the alpha 1a and alpha 1b appear not to be responsible for the manifestation of hypertension during this phase.

Animals↗
PubMed1992

Rapid renal potassium adaptation in rats.

The possibility that renal K adaptation, defined as the increased capacity to excrete an intravenous K load, can occur within hours of intake of a normal K ration was examined in fed and fasted rats. Rats maintained on a 12-h light-dark cycle were fed either a standard diet (fed rats) or had food removed before the onset of the dark phase to prevent the early dark phase ingestion (fasted rats). Four hours into the dark phase, fed and fasted rats were infused intravenously with 0.143 M KCl, while control fed and fasted rats did not receive any KCl. The initial urinary K excretion rate (UKV, 5.67 +/- 0.47 in K-loaded fed rats were greater than the UKV (3.13 +/- 0.45 mu eq/min) and PK (3.24 +/- 0.1 meq/l) in K-loaded fasted rats. After the acute KCl infusion (100 min), the UKV increased similarly in both fed and fasted rats, while the magnitude of the increase in PK in fasted rats was twice that in fed rats. Consequently, the delta UKV/delta PK was greater in fed rats (3.83 mj eq/min per meq/l) than in fasted rats (2.14 mu eq/min per meq/l). During the KCl infusion for any level of PK, the UKV was greater in fed rats than in fasted rats. This relationship was not altered by concurrent infusion of potassium canrenoate or somatostatin. These results indicate that within 3-6 h after an oral K intake, the renal excretion of an acute intravenous K load is enhanced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1991

Protein synthesis is required for cholera toxin-induced stimulation of arachidonic acid metabolism.

The molecular events in the mechanism of action of cholera toxin were analyzed using Chinese hamster ovary (CHO) cells. Cholera toxin stimulated both 3',5'-cyclic adenosine monophosphate (cAMP) synthesis and arachidonic acid metabolism in these cells. The turnover of phospholipid by cholera toxin-induced stimulation of phospholipase activity evoked the synthesis of PGE2 and other prostaglandins. Cholera toxin-induced release of both [3H]arachidonic acid and PGE2 was blocked by addition of either cycloheximide or actinomycin D. In contrast, accumulation of cAMP in cholera toxin-treated CHO cells was unaffected by adding these drugs. Further, dibutyryl cAMP or forskolin caused [3H]arachidonic acid release, which also was blocked by cycloheximide and actinomycin D. We concluded that the sequence of molecular events in cholera toxin-treated CHO cells first involved activation of adenylate cyclase, which caused an increase in cAMP. In turn, cAMP promoted transcription of mRNA that encoded either a specific phospholipase or a phospholipase-activating protein. The emerging arachidonic acid metabolites (e.g., PGE2 and PGF2 alpha) might be important mediators of cholera toxin's stimulatory effects on vascular permeability and smooth muscle contraction in the intestine during cholera.

Animals↗