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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1998

Stroke in children and sickle-cell disease: Baltimore-Washington Cooperative Young Stroke Study.

BACKGROUND/PURPOSE: The Baltimore-Washington Cooperative Young Stroke Study is the largest biracial urban-suburban population-based study to examine the etiology of strokes in children. METHODS: We identified all children aged 1 to 14 years discharged from all 46 hospitals in central Maryland and Washington, DC with a diagnosis of ischemic stroke and intracerebral hemorrhage in the years 1988 and 1991. Each medical record was reviewed by two neurologists for appropriateness of the diagnosis of stroke and for information on the patient's history, clinical presentation, pertinent investigations, hospital stay, and outcome at time of discharge. RESULTS: Eighteen children with ischemic infarction and 17 with intracerebral hemorrhage were identified. The most common cause of ischemic stroke was sickle-cell disease (39%), followed by vasculopathic (33%) and indeterminate (28%) causes. Causes of intracerebral hemorrhages were arteriovenous malformation (29%), hematologic (23%), vasculopathy (18%), surgical complication (12%), coagulopathy (6%), and indeterminate (12%). The overall incidence for childhood stroke was 1.29 per 100,000 per year, with ischemic stroke occurring at a rate of 0.58 per 100,000 and intracerebral hemorrhage occurring at a rate of 0.71 per 100,000. The incidence of stroke among children with sickle-cell disease was estimated to be 0.28% or 285 per 100,000 per year. CONCLUSION: Sickle-cell disease plays a disproportionately high role in childhood stroke when a biracial population is surveyed.

Adolescent↗
PubMed1998

Decreasing nonurgent emergency department utilization by Medicaid children.

OBJECTIVE: To test interventions to decrease the utilization of hospital emergency departments (EDs) for routine, nonemergent health care among Medicaid recipients. METHODS: Families of a Medicaid-recipient child presenting to a children's hospital ED for nonurgent problems received information from either a health professional or a clerical employee about the importance of a primary care provider and assistance with making an appointment to the provider of their choice. The health professional continued to work with her assigned families in eliminating barriers to appropriate utilization of a primary care provider for up to 3 months after the index ED visit. A third (comparison) group received no intervention. Subsequent health care utilization for each enrollee was tracked via Ohio Medicaid claims data throughout the four subsequent 6-month periods after the index ED visit. RESULTS: Children in the intervention groups had 11.1% and 14.5% fewer nonurgent ED visits in the 6 months after the index ED visit with a concomitant decrease in cost for this type of care when compared with the comparison group during the same time period. No difference in the number of preventive or ill-child primary care visits was seen. There was no difference in health care cost or utilization in the time period 6 to 24 months after the intervention. CONCLUSIONS: Interventions in pediatric EDs aimed at decreasing subsequent ED utilization for nonurgent care can be effective, resulting in modest decreases in the cost of health care for a Medicaid population.

Adolescent↗
PubMed1998

Young inner-city children visiting the emergency room (ER) for asthma: risk factors and chronic care behaviors.

Inner-city children visiting emergency rooms (ER) for asthma often rely on the ER as their primary source of care. To evaluate chronic asthma control, structured interviews were conducted with the adult accompanying a sample of 46 children, 2-6 years old, presenting to an inner-city pediatric ER for asthma. Fifty-one percent had 10 or more prior ER visits and 46% had 2 or more previous hospitalizations. Seventy-two percent had functional severity scores in the moderate to severe range. Only 11% used daily inhaled anti-inflammatory medication. Not one patient had a written self-management plan. Most young children visiting an inner-city ER for asthma have poorly controlled and poorly managed chronic asthma.

Albuterol↗
PubMed1998

Comparison of single- and triple-dose contrast material in the MR screening of brain metastases.

PURPOSE: Although studies obtained with triple-dose contrast administration can show more brain metastases than those obtained with single-dose contrast material in patients with multiple metastases, such studies are costly and of limited clinical benefit. Since most patients who undergo screening have negative findings or a single metastasis, this study was performed to compare the clinical utility of single-dose versus triple-dose contrast administration in this large group of patients who could benefit from the possible increased sensitivity in lesion detection. METHODS: Ninety-two consecutive patients with negative or equivocal findings or a solitary metastasis on single-dose contrast-enhanced MR images underwent triple-dose studies. Findings were compared with a standard of reference composed of panel review and long-term follow-up. Further analysis was performed by comparing results with those obtained by two blinded readers. RESULTS: In all 70 negative single-dose studies, the triple-dose studies depicted no additional metastases in terms of the standard of reference. No statistically significant difference was seen between the results of the single- and triple-dose studies. For 10 equivocal single-dose studies, the triple-dose study helped clarify the presence or absence of metastases in 50% of the cases. In 12 patients with a solitary metastasis seen on the single-dose study, the triple-dose study depicted additional metastases in 25% of the cases. In the results of one of the two blinded readers, use of triple-dose contrast led to a statistical difference by decreasing the number of equivocal readings but at the expense of increasing the number of false-positive readings. CONCLUSION: Routine triple-dose contrast administration in all cases of suspected brain metastasis is not helpful. On the basis of our investigation, we conclude that the use of triple-dose contrast material is beneficial in selected cases with equivocal findings or solitary metastasis, although with the disadvantage of increasing the number of false-positive results.

Brain↗
PubMed1998

Post kidney transplant quality of life prediction models.

UNLABELLED: Quality of life (QoL) is generally found to improve for renal transplant recipients, although some patients continue to experience health-related problems. It was within this context that we undertook our investigation which focused on identifying the factors predictive of QoL following kidney transplantation. METHODS: The sample included 91 non-diabetic patients of which 69 provided 6-month data and 68 provided 12-month data. Three QoL questionnaires were administered to capture as many QoL dimensions as possible. Repeated measure analyses of variance with multiple post hoc comparisons of LS means was conducted to determine how QoL outcomes differed over time. Correlational analyses were performed on the 12-month dataset to determine which variables to include in the modeling process. Multiple stepwise regression with forward and backward entry were used in the prediction modeling. RESULTS: Essentially all patients experienced a significant improvement in QoL and the improvement occurred early and appeared to be sustained. Five separate prediction models were constructed, each including number of hospital days in first 6 months, employment, and social support. CONCLUSIONS: The similarity of the five models is of note. It is not necessarily these specific variables per se that predict QoL outcomes, but rather what they conceptually represent. These findings provide direction for interventions designed to enhance post-transplant QoL.

Adult↗
PubMed1998

Multiple systemic emboli complicating the course of a patient with an atrial septal defect, an atrial septal aneurysm and an endocardial right atrial pacemaker lead.

We describe an adult patient with a large atrial septal defect, an atrial septal aneurysm and thrombus formation on a transvenous right atrial pacing lead. Because of right-to-left shunting through the atrial septal defect, she developed multiple systemic emboli to the spleen and left kidney (with infarcts), to the left leg, and probably to the brain as a cerebrovascular accident. The fundamental guiding principle of avoiding endocardial pacing leads in patients with congenital intracardiac communications, was violated in this patient, leading to serious dire consequences and complications.

Aged↗
PubMed1997

Mental health. Sending in the paras.

Community support workers have become a common feature of mental health services. They work mainly with people with severe mental illness and offer intense support. Their need for training should be considered.

Allied Health Personnel↗
PubMed1997

Screening for colorectal cancer. A comparison of 3 fecal occult blood tests.

BACKGROUND: Colorectal cancer is the second leading cause of cancer deaths in the United States. Fecal occult blood testing has become a standard screening test for large-bowel cancers in the average asymptomatic population. Performance characteristics of the test and physician and participant compliance are the 2 major elements that impact the success of screening and early detection. OBJECTIVES: To evaluate the nonhydrated Hemoccult, rehydrated Hemoccult, and Hemoccult SENSA tests (SmithKline Diagnostics Inc, Palo Alto, Calif) and to assess participant and physician compliance. METHODS: A mass community-based screening study in an urban setting. Kits were distributed by a local pharmacy and at community sites. Diagnostic tests were completed through physicians' offices and clinics. Participants were asymptomatic and aged 50 years or older. Those who tested positive were advised to follow up with a physician. RESULTS: An overall positivity rate of 16% was reported for the 8293 kits that were processed. Rehydrated Hemoccult had a positivity rate of 15%; Hemoccult SENSA, 7%; and nonhydrated Hemoccult, 5%. The positive predictive value of nonhydrated Hemoccult was 14%; rehydrated Hemoccult, 7%; and Hemoccult SENSA, 11%. Of those who tested positive, 59% had a colonoscopy or flexible sigmoidoscopy and double-contrast barium enema examination on follow-up. Recommended follow-up was more frequent for those who consulted a gastroenterologist. CONCLUSIONS: Rehydrated Hemoccult yielded a higher positivity rate and lower positive predictive value than either Hemoccult SENSA or nonhydrated Hemoccult. Hemoccult SENSA approached the positive predictive value of nonhydrated Hemoccult. Adequacy of follow-up of patients testing positive for fecal occult blood needs improvement.

Aged↗
PubMed1997

Influence of glaucomatous visual field loss on health-related quality of life.

We examined the influence of glaucomatous visual field defects on vision-targeted and generic health-related quality of life. Vision-targeted and generic health status were assessed across 5 glaucoma treatment categories and a normal reference group from 5 tertiary care ophthalmology practices during regularly scheduled eye care visits. The sample consisted of 147 patients who were members of specific glaucoma treatment categories and 44 reference group patients. For patients with glaucoma, eligibility included a diagnosis of glaucoma at least 1 year prior to enrollment and no evidence of other eye disease. Participants completed 2 vision-targeted surveys, the National Eye Institute Visual Functioning Questionnaire and the VF-14, and a generic health-related quality of life measure, the Medical Outcomes Study 36-Item Short Form. Data from automated perimetry (Humphrey Field Analyzer 24-2, Humphrey Instruments, San Leandro, Calif) were used to generate Advanced Glaucoma Intervention Study scores for all participants. The Medical Outcomes Study 36-Item Short Form scores from glaucoma and reference group participants collected on a random half of the sample were similar. However, comparisons of the vision-targeted surveys demonstrated significant mean differences on 7 of 11 National Eye Institute Visual Functioning Questionnaire scales, and a trend toward significant differences for the VF-14 (P < .07 by linear regression). Greater visual field defects in the better eye were significantly associated with poorer National Eye Institute Visual Functioning Questionnaire scores (P < .05), as well as with worse VF-14 scores. These findings were most dramatic for patients with the most severe field loss in the better eye. Vision-targeted questionnaires were more sensitive than a generic health-related quality of life measure to differences between glaucoma and normal reference participants. Our findings indicate that self-reports of vision-targeted health-related quality of life are sensitive to visual field loss and may be useful in tandem with the clinical examination to fully understand outcomes of treatment for glaucoma.

Adult↗
PubMed1997

Platelet-activating factor in plasma of patients with sickle cell disease in steady state.

The role of platelet-activating factor (PAF) in the pathogenesis of microvascular vaso-occlusion in sickle cell disease (SCD) is not known. In order to assess a role for PAF in vaso-occlusion in patients with SCD in steady state conditions, we measured plasma PAF level and plasma PAF acetylhydrolase activity as indices of PAF metabolism in vivo. We also studied PAF synthesis, from (3H)-acetate, by purified platelets stimulated with A23187. PAF was extracted from plasma of ten patients with SCD in steady state and from age-matched controls. PAF, purified by thin-layer chromatography, was quantitated by radioimmunoassay. PAF level (mean +/- SEM, pg/ml) in plasma of controls was 393 +/- 65, which was significantly lower than the 797 +/- 62 measured in plasma of patients with SCD. There was no difference in acetylhydrolase activity between the two groups. PAF synthesis (mean +/- SEM, nmol/10(6) cells) by platelets of controls without exogenous lyso-PAF was 1.69 +/- 0.24, higher than the 0.59 +/- 0.038 synthesized by platelets of patients with SCD. Incubation of platelets with 1.0 micromol/L lyso-PAF increased PAF synthesis by controls to 8.93 +/- 1.76, still higher than the 4.59 +/- 0.98 synthesized by platelets of patients with SCD. Our data show that patients with SCD are susceptible to a higher circulating levels of PAF in vivo during steady-state conditions. We speculate that higher levels of PAF may be a contributing factor to the persistent stress and inflammatory state of the microcirculation of patients with SCD.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1997

Simian foamy virus type 1 (SFV-1) induces apoptosis.

Foamy virus infection causes cytopathology in several cell types from different species. The mechanism of cell killing by foamy viruses is not known. In this report, the mechanism of cell death induced by simian foamy virus type 1 (SFV-1) infection was investigated in fibroblast and lymphoid derived cells lines. Infected L-929 (fibroblast) and Raji (B cell) cells showed chromatin condensation, chromatin cleavage into nucleosome oligomers, and ultrastructural changes consistent with apoptosis. These data suggest that SFV-1 induced apoptotic cell death in different cell lines from different species. The degree of apoptotic cell death in both L-929 and Raji cell lines correlated with increased virus replication. Apoptosis, therefore, is one mechanism by which SFV-1 causes cell death.

Animals↗