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B Johnson

Publications and source records attributed to B Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1998

Isradipine prevents global and regional cocaine-induced changes in brain blood flow: a preliminary study.

The L-type calcium channel antagonist, isradipine, reduces brain ischemia in animal models of ischemic stroke. These effects of isradipine appear more pronounced in dopamine (DA) rich brain regions. These same DA-rich brain regions have also been shown to be the areas most affected by cocaine-induced ischemic changes. Using a novel quantified approach to single photon emission computerized tomography, we demonstrated that isradipine pre-treatment prevented cocaine-induced ischemic changes, especially in these DA-rich brain regions. This is the first demonstration that any medication, including isradipine, can prevent the ischemic effects of cocaine on brain blood flow. Isradipine may, therefore, be a useful therapeutic agent for the prevention of brain ischemia in cocaine addicts.

Adult↗
PubMed1998

Differences in the luminance of the first and second displays affects visible persistence in opposite ways.

Visible persistence was measured using a two-frame temporal integration paradigm. Most such studies match the brightness of the two frames, and find that equal increases in the brightness of the frames impairs performance on the task. This suggests that increases in frame brightness decrease the duration of visible persistence. Little is known about what happens when the frames differ in brightness. In this study, the luminance intensities of the first and second frames were set at five different intensity levels in a factorial arrangement. Increasing the intensity of the first frame improved performance, whereas increasing the intensity of the second frame impaired performance. These results suggest, contrary to the findings with brightness-matched frames, that increasing the intensity of one frame increases the duration of visible persistence of that frame. A mathematical model supports this conclusion.

Afterimage↗
PubMed1998

Colposcopy in evaluation of the adult sexual assault victim.

The purpose of this study was to determine if the colposcope improves detection of genital trauma in adult women who are victims of sexual assault compared with gross visual examination alone. A prospective, 1-month pilot study was conducted of 17 women patients who presented consecutively to Charity Hospital New Orleans during April 1994 requesting sexual assault examinations. Use of the colposcope allowed documentation of trauma in 9 of the 17 sexual assault victims (53%), compared with 1 of 17 (6%) by gross visualization alone (statistically significant: chi2 = 0.64, P = .0114). The colposcope improved detection of genital trauma in adult female sexual assault victims as compared with gross visual examination alone at a statistically significant level.

Adolescent↗
PubMed1998

Delay of estradiol-induced surge secretion of LH in gilts by intracerebroventricular injection of morphine.

In Experiment 1, ovariectomized (OVX) gilts, 143 d old and 58.5 +/- 1.8 kg BW, received 10 micrograms estradiol benzoate (EB)/kg BW i.m. and either 500 micrograms of the endogenous opioid peptide (EOP) agonist, morphine (MOR), in saline (SAL; n = 5), or SAL (n = 4) intracerebro-ventricularly at 40 and 48 hr after EB. With the exception of one MOR-treated gilt, which was deleted from Experiment 1, LH secretion was suppressed for at least 50 hr in all gilts. Timing of the LH surge was similar among gilts. However, total LH secreted was greater (P < 0.05) after SAL than MOR. The experiment was repeated at 179 d of age and 78.6 +/- 1.2 kg BW, except that treatments were reversed among gilts. Emergence of the LH surge was delayed (P < 0.005) by 10.8 hr and time to maximum LH concentration (P < 0.05) by 6.8 hr after MOR than after SAL. Magnitude and total LH secreted were not different among gilts. In Experiment 2, gilts which had displayed estrous cycles of 18-22 d were OVX and treated as in Experiment 1, except MOR (n = 3) or SAL (n = 4) were injected 10 hr later than in Experiment 1, i.e., at 50 and 58 hr after EB. Secretion of LH was suppressed for at least 60 hr in both groups. Time to emergence of the LH surge was delayed by 27 hr (P < 0.05) after MOR compared to after SAL. However, other parameters of the surge were not different among gilts. Thus, EOP modulate LH surge secretion negatively in the pig.

Animals↗
PubMed1998

Demonstration of dose-dependent global and regional cocaine-induced reductions in brain blood flow using a novel approach to quantitative single photon emission computerized tomography.

Ischemic stroke is a common cause of morbidity and mortality in cocaine addicts. Because the previous semiquantitative single photon emission computerized tomography (SPECT) method for measuring brain blood flow does not quantify blood flow, the magnitude and specificity of cocaine's effects during drug taking has not been well established. Here, using a novel quantitative approach to SPECT, we established that intravenous cocaine administration to nine recently abstinent cocaine-dependent subjects was associated with significant decreases in global and regional brain blood flow to dopamine-rich areas such as the prefrontal, frontal temporal, and subcortical gray matter. Establishing the utility of this relatively new quantitative SPECT technique provides an important tool for the management of vascular disorders of the brain. Additionally, identifying the site-specific effects of cocaine provides targets for the development of putative therapeutic medications to attenuate or minimize ischemic stroke in cocaine addicts.

Adolescent↗
PubMed1998

Chronically mentally ill individuals re-entering the community after hospitalization.

The purpose of this phenomenological study was to increase the understanding of the experiences of chronically mentally ill individuals who are re-entering the community after hospitalization. Ten individuals from an acute care psychiatric hospital who had had two or more admissions within a 12-month period were interviewed, shortly before discharge and subsequently between two and four times while in the community. Three interrelated themes emerged. First, at the time of discharge, the optimism of the participants about returning home was tempered by a realistic recognition of their problems. As time passed, their problems seemed to become their preoccupying focus and optimism faded. Second, for most of the participants, relationships with others, positive, negative or both, played an important role in their return to home and community. Third, participants who experienced more positive social relationships also described individual achievements and community involvement. The re-entry process was not a smooth transition for these individuals.

Adaptation, Psychological↗
PubMed1998

Total parenteral nutrition via multilumen catheters does not increase the risk of catheter-related sepsis: a randomized, prospective study.

The purpose of this study was to determine in a randomized, prospective manner whether administration of total parenteral nutrition (TPN) via multilumen catheters increases the risk of catheter-related sepsis (CRS). All patients receiving hyperalimentation during a 24-month period were randomized to receive either a double-lumen catheter (DLC) or a triple-lumen catheter (TLC). A total of 101 catheters were placed in 79 patients, of which 49 were DLCs and 52 were TLCs. The patients with DLCs received a total of 784 days of TPN, whereas patients with TLCs received a total of 754 days of TPN. CRS was associated with one (2.0%) of the 49 DLCs vs. one (1.9%) of the 52 TLCs. In comparison, the rate of CRS associated with single-lumen catheters (historical control) at our institution was 1.4% (P > .90). We conclude that the use of multilumen catheters in TPN therapy does not result in an increased risk of CRS.

Catheterization, Central Venous↗
PubMed1998

Evidence for a luteinizing hormone surge center in the hypothalamus of the pig.

Studies were conducted to determine whether there is an LH surge generator in the hypothalamus of the pig. In experiment 1, 157-day-old ovariectomized (OVX) gilts received 1.5 microg estradiol benzoate (EB)/kg BW i.m. every 12 h from 0 through 24, 48, 72, or 96 h. Blood was sampled every 6 h from 3 to 36 h and every 3 h from 36 through 144 h. One of 3, 4 of 4, 4 of 4, and 2 of 3 gilts displayed an LH surge after treatment for 24, 48, 72, and 96 h, respectively. With the exception that time to maximum LH concentration was greater in gilts treated for 96 h than in those treated for 72 h (p < 0.05), parameters of the surge were similar among all gilts. In experiment 2a, an Alzet osmotic pump containing EB or vehicle was inserted s.c. behind an ear of 124-day-old OVX gilts, resulting in the following daily doses of EB: 0, 0.75, 1.50, or 3.00 microg/kg BW. Blood was sampled at 0, 2, 4, 6, and 8 h and every 8 h thereafter through 168 h to evaluate surge secretion of LH, and every 15 min for 8 h starting at 168 h to evaluate pulsatile LH secretion. Zero of 3, 0 of 2, 3 of 3, and 3 of 3 gilts displayed an LH surge after 0, 0.75, 1.50, and 3.00 microg EB/kg BW, respectively. Parameters of the surge were similar among gilts. Pulsatile LH secretion, evaluated 7 days after pump insertion, was significantly suppressed for estradiol-treated gilts compared to controls. In experiment 2b, at 182 days of age, 10 gilts used in experiment 2a plus 2 additional gilts in the original group prepared but not used for experiment 2a, were randomly assigned in groups (n=3) to the following daily doses of EB: 0, 0.19, 0.38, or 0.75 microg/kg BW, administered again by osmotic pump. Treatment and blood-sampling schedules were the same as in experiment 2a. Zero, 0, 1, and 2 gilts displayed an LH surge after treatment with 0, 0.19, 0.38, and 0.75 microg EB/kg BW, respectively. Parameters of the surge were similar among gilts that displayed an LH surge. Pulsatile LH secretion was significantly suppressed for estradiol-treated gilts compared to controls. Thus, the LH surge resulted from positive feedback stimulation of a specific surge generator rather than attenuation or dissipation of negative feedback inhibition of estradiol on a pulse generator.

Animals↗
PubMed1998

Extending the pipeline for minority physicians: a comprehensive program for minority faculty development.

Medical schools must become more successful in training minority faculty. Minority faculty development programs at schools of medicine must involve trainees from the undergraduate years (if not before) through junior faculty and must involve MD and combine-degree (MD-PhD) students. The authors describe the comprehensive minority faculty development program at the University of Pennsylvania School of Medicine, which involves minority undergraduates, medical students, residents, fellows, and faculty. This program provides the administrative staff and research methodologists to assist trainees at all levels across all departments in the school of medicine. The principal student recruitment program is the undergraduate premedicine enrichment program. The medical student component provides general counseling, research development, and activities to enhance performance in the clinical courses. The components for advanced trainees (residents, fellows, and postdoctoral trainees) and faculty consist of training in research methods, mentoring, teaching skills, and scientific writing skills. Through this program, the University of Pennsylvania School of Medicine has increased the number of under-represented minority faculty by 32% since 1993-94 and created an environment conducive to the professional growth and development of minority faculty.

Black or African American↗
PubMed1998

Assessing individual family members' constructions of family problems.

Much contemporary family therapy theory and practice takes into account clients' cognitive constructions of their family problems. Recent calls for therapists to elicit and work with clients' causal explanations and narratives parallel accumulating evidence in the social-clinical literature about the predictive importance of attributions in family relationships. In this article, we introduce the Constructions of Problems Scale (CPS), provide preliminary evidence of its reliability and validity, and suggest ways in which it can be used clinically to reveal new areas for questioning and to generate new ideas. The CPS is a brief questionnaire that can be used to create a profile of each individual family member's private constructions. To complete the CPS, each family member writes a free-form narrative of the presenting problem and then rates his or her perceptions of the contributing causes. The CPS profiles can be used to compare the perspectives of different family members and to assess cognitive constructions at different points in treatment. We discuss its potential for these and other clinical uses.

Adult↗
PubMed1998

Barriers to seeking care following school vision screening in Rochester, Minnesota.

School vision screening provides an effective way to identify children who require vision therapy, usually glasses. To benefit from screening, children with abnormal screening test results must receive follow-up eye care, but care may be delayed for months or years. This project used community focus groups in Rochester, Minn., to identify barriers that may delay seeking professional care following school vision screening. Major barriers identified included lack of community awareness about the frequency and potential effect of refractive errors in children, a parental perception of inadequate communication between schools and the parents and community, high cost of corrective lenses, limited availability of convenient eye care appointments, and adolescents reluctance to wear glasses. Program planners developed a community action plan to address the perceived barriers.

Adolescent↗
PubMed1998

Comparison of disease in calves dosed orally with oak or commercial tannic acid.

Commercial tannic acid has been used as a substitute for leaves and acorns in studies of oak toxicosis in some species. The toxicity of a commercial tannic acid given orally to calves was determined, and the clinical signs, laboratory findings, and pyrogallol production were compared with those found in calves dosed orally with oak leaves. The oak-fed calves developed the clinical signs and lesions characteristic of renal failure. Proteinuria developed by 48 hours in 1 calf and by 72 hours in the other calf. Both calves developed hematuria on day 4 and glucosuria on day 5. The blood urea nitrogen and creatinine values increased markedly on day 6. Pyrogallol was detected in the serum only at 3 and 6 hours after the calves began ingesting the oak leaves. Pyrogallol was detected in urine from 1 calf until 60 hours and in the other calf until 48 hours after the beginning of oak intake. The 2 calves that were dosed with tannic acid at the same level as found in the leaves fed to the other calves did not develop clinical signs, abnormal laboratory findings, or pyrogallol production. Calves given high levels of tannic acid at doses of 4.4-5.5 g/kg developed methemoglobinemia rather than renal disease. Therefore, commercial tannic acid given orally cannot be used as a substitute for oak in studies of toxicosis in cattle.

Animals↗
PubMed1998

Serum interleukin-6 levels in metastatic renal cell carcinoma before treatment with interleukin-2 correlates with paraneoplastic syndromes but not patient survival.

PURPOSE: We sought to determine the frequency of interleukin-6 (IL-6) expression in renal cancer cell lines, the frequency of the detection of IL-6 in the serum of patients with metastatic renal cell carcinoma, whether serum IL-6 level correlates with the development of paraneoplastic syndromes and whether serum IL-6 level in patients with metastatic renal cancer correlates with response to treatment with interleukin-2 (IL-2) or patient survival. MATERIALS AND METHODS: Conditioned media from 21 cell lines from 20 patients were examined for IL-6. We identified 2 matched groups of patients with metastatic renal cancer (30 responders and 29 nonresponders) to IL-2 based immunotherapy. Stored pretreatment serum specimens were evaluated for IL-6. Medical records were reviewed to determine the presence of paraneoplastic syndromes. RESULTS: IL-6 was detected in 19 of 21 renal cancer cell lines (90%) obtained from 20 patients with metastatic renal cancer as well as in the serum of 33 of 59 patients (56%) with metastatic renal cell carcinoma. A significant association between serum IL-6 level and anemia (p = 0.0032), elevated platelet count (p = 0.01), decreased albumin (p = 0.034) and elevated alkaline phosphatase (p = 0.04) was found. A trend was noted of the association of increased serum IL-6 level and fever (p = 0.051). No correlation was found between pretreatment serum IL-6 level and survival or response to IL-2. CONCLUSIONS: IL-6 was frequently secreted by renal cancer cell lines but it was only present in the serum of approximately half of the patients with metastatic renal cancer. Elevations of serum IL-6 were associated with paraneoplastic manifestations frequently seen in patients with renal cancer, including anemia, thrombocytosis, decreased albumin and elevations of alkaline phosphatase (Stauffer's syndrome). A weak relationship was noted between serum IL-6 level and fever but none was noted between that and survival or response to IL-2.

Adult↗