Biomedical subjects
J Clark
Publications and source records attributed to J Clark.
Development of the living-related donor liver transplant program at the Texas Medical Center: initial results and surgical complications.
Explore the source record for details and available documents.
A pilot project for Georgia "growing healthy" in Ware County.
Explore the source record for details and available documents.
How to aspirate fluid from small-bore feeding tubes.
Explore the source record for details and available documents.
High-dose intravenous zidovudine with 5-fluorouracil and leucovorin. A phase I trial.
BACKGROUND: The inhibition of pyrimidine metabolism by 5-fluorouracil (5-FU) enhances the anti-cancer effects of zidovudine (formerly called AZT) in in vitro and in vivo model systems without additive toxicity. Zidovudine-induced DNA damage correlates with cytotoxicity. METHODS: A Phase I trial of high-dose continuous-infusion intravenous zidovudine therapy in combination with 5-FU and leucovorin therapy was performed. Eighteen patients with advanced malignant tumors were treated with 43 courses of oral leucovorin (50 mg every 4 hours); continuous-infusion 5-FU (800 mg/M2/day) for 72 hours (3 days); and zidovudine, begun 24 hours after the start of 5-FU and leucovorin, for 48 hours, and terminating with the end of the 5-FU infusion. Zidovudine plasma levels and zidovudine-induced DNA damage were assessed. RESULTS: Zidovudine administered in doses of 2-20 g/M2/day, added no obvious toxicity to the basic chemotherapeutic treatment with 5-FU and leucovorin but resulted in a dose-dependent biologic effect manifested by an increase in DNA strand breaks in peripheral blood cells. At doses greater than 15 g/M2/day, altered plasma kinetics of zidovudine were observed; plasma zidovudine levels increased dramatically in relation to the dose of zidovudine. Limitations in drug administration restricted administration of higher intravenous doses without achieving a maximally tolerated dose. No responses were seen in this heavily pretreated population. CONCLUSIONS: Based on the results of preclinical studies, plasma zidovudine levels greater than those achieved at the maximal dose (133 microns) are required for increased anti-cancer activity with 5-FU. Additional studies using a bolus or rapid infusion as a method of achieving higher peak levels are indicated.
The amino terminus of ADP-ribosylation factor (ARF) is a critical determinant of ARF activities and is a potent and specific inhibitor of protein transport.
Deletion of the amino-terminal 17 residues from human ADP-ribosylation factor (ARF) resulted in a protein ([delta 1-17]mARF1p) devoid of ARF activity but which retained the ability to bind guanine nucleotides with high affinity. Unlike the wild type, the binding of guanine nucleotides to this deletion mutant was found to be independent of added phospholipids. A chimeric protein was produced, consisting of 10% (the amino-terminal 17 amino acids) human ARF1p and 90% ARL1p, an ARF-like protein (55% identical protein sequence) from Drosophila. This chimera was found to have ARF activity, lacking in the parental ARL1 protein. Thus, the amino terminus of ARF1p was shown to be a critical component of ARF activity. A synthetic peptide, derived from the amino terminus of ARF1p, has no ARF activity. Rather, the peptide was found to be a specific inhibitor of ARF activities. This peptide was also found to be a potent and specific inhibitor of both an in vitro intra-Golgi transport assay and the guanosine 5'-3-O-(thio)triphosphate-stimulated accumulation of coated vesicles and buds from Golgi preparations. We conclude that ARF is required for the budding of coated vesicles from the Golgi stacks and serves a regulatory role in protein secretion through the Golgi in eukaryotic cells.
Continuous infusion of highly purified factor VIII (Monoclate M)
Explore the source record for details and available documents.
Estimating the severity of osteoarthritis with magnetic resonance spectroscopy.
This study explores the possibility of estimating the severity of osteoarthritis in the elderly through magnetic resonance measurements of proton relaxation times in articular cartilage. Twenty-five paired samples were cut from eight cartilage specimens. The specimens had been taken in the normal course of knee surgery from patients aged 60 years or older. The reciprocal of the T1 relaxation time (1/T1) was found to have a negative association with the histological-histochemical grade of the severity of osteoarthritis. A revised, weighted version of the Mankin-Dorfman severity scale yielded stronger correlations with 1/T1 and with percent water. A nonlinear regression equation expressing osteoarthritis as a function of 1/T1 explained 38% of the variation in the severity of osteoarthritis as measured by the new scale. A superior methodology for estimating the severity of osteoarthritis on the basis of contour maps of the magnetic resonance response is suggested.
Dietary phytoestrogens and cancer: in vitro and in vivo studies.
Thirty postmenopausal women (11 omnivores, 10 vegetarians and 9 apparently healthy women with surgically removed breast cancer) were investigated with regard to the association of their urinary excretion of estrogens, lignans and isoflavonoids (all diphenols) with plasma sex hormone binding globulin (SHBG). A statistically significant positive correlation between urinary total diphenol excretion and plasma SHBG was found which remained statistically significant after elimination of the confounding effect of body mass determined by body mass index (BMI). Furthermore we found a statistically significant negative correlation between plasma SHBG and urinary excretion of 16 alpha-hydroxyestrone and estriol which also remained significant after eliminating the effect of BMI. Furthermore we observed that enterolactone (Enl) stimulates the synthesis of SHBG by HepG2 liver cancer cells in culture acting synergistically with estradiol and at physiological concentrations. Enl was rapidly conjugated by the liver cells, mainly to its monosulfate. Several lignans and the isoflavonoids daidzein and equol were found to compete with estradiol for binding to the rat uterine type II estrogen binding site (the s.c. bioflavonoid receptor). It is suggested that lignans and isoflavonoids may affect uptake and metabolism of sex hormones by participating in the regulation of plasma SHBG levels and in this way influence their biological activity and that they may inhibit cancer cell growth like some flavonoids by competing with estradiol for the type II estrogen binding sites.
Management of an outbreak of Norwegian scabies.
An outbreak of Norwegian scabies in a 170-bed acute care hospital was controlled through an organized plan for delivering treatment to those affected: four patients, 50 staff members, and 14 family members of staff members. Health departments in two counties were notified and found four additional cases in the long-term care facility at which the index patient lived. Contact isolation was used for the index patient and any other patients with nosocomial scabies. Staff members infested with Sarcoptes scabiei were released from work until they had been treated with lindane. Staff members who had been in contact with infested persons and staff members' families were treated prophylactically with lindane. This aggressive treatment plan resulted in rapid resolution of the outbreak.
Analysis of set screw and side-lock connector reliability.
A retrospective review of complications with connectors and lead-to-header interfaces was performed following 649 pacing procedures between 1980 and 1990. There were 88 lead revisions (13.6%), 81 device replacements or modifications (12.5%), and 480 new implants (74%) using devices of five manufacturers. Two basic connector types were studied, one utilizing a set screw and the other using a side-lock compression fitting. The set screw makes electrical contact and mechanically secures the lead connector pin with a set screw insulated by a self-sealing grommet or an integral or separate set screw cover. The side-lock makes electrical contact with an automatic spring mechanism while the plastic lead terminal is secured in the connector block of the pacemaker by a Delrin side-lock compression fitting. Four hundred fifty-nine set screw connector devices were followed for up to 12 years with 14 complications (3.1%) whereas 82 side-lock connector devices were followed for up to 5 years with one complication (1.2%). The set screw and side-lock connectors were reliable over the period of follow-up. Although the complication rate appeared lower with the side-lock, follow-up was shorter and the number of implants smaller. With the leads used in this study, the side-lock proved to be a desirable feature due to simplicity, speed, safety, and ease of use. One limitation is the requirement for a precise IS-1 connector terminal diameter.
The potential role of custody facilities in controlling sexually transmitted diseases.
BACKGROUND: The National Commission on Correctional Health Care recommends that medical screening, including tests for syphilis and other sexually transmitted diseases, be performed by the 14th day after initial booking procedures. Because the average length of stay in detention is usually less than 14 days, most detainees are not screened or treated for asymptomatic communicable diseases. METHODS: In order to determine the incidence and prevalence of syphilis among those booked through a large county jail, a rapid screening procedure to test newly incarcerated inmates and treat those infected was implemented over a 3-week period. RESULTS: Among 6309 detainees eligible for testing during the 3-week period of the study, 129 (2%) were diagnosed with syphilis. During the preceding month when only those reporting symptoms or high-risk behaviors were screened, 20 cases were diagnosed. The sensitivity and predictive value of self-reported risk factors for syphilis infection were low. Among the first 110 diagnosed cases, 17 (15.5%) were released within 3 days and 86 (78%) were released within 6 days. CONCLUSIONS: If screening and treatment for syphilis are delayed until the 14th day after booking, the majority of infected inmates will be released prior to evaluation and treatment. Rapid screening and treatment for selected sexually transmitted diseases are likely to be an effective public health measure when implemented in custody settings.
The psychological adjustment of offspring of adults with obsessive-compulsive disorder: a brief report.
This study describes the prevalence of emotional and behavioural problems in the offspring of parents who are members of the Obsessive-Compulsive Neurosis Support Group in South Australia. The results suggest that the offspring of adults with obsessive-compulsive disorder do not have more problems than other children and adolescents in the community. The study also highlights potential benefits of collaborative research conducted by research groups and self-help organisations.
Differences between reports from children, parents and teachers: implications for epidemiological studies.
This study describes the different prevalences obtained when varying combinations of informants were used to identify emotional and behavioural disorders in a representative sample of 336 children living in two-parent families in the community of Adelaide, South Australia. When different informants were used to identify children with disorders, the estimated prevalences ranged from 3.3 +/- 1.6% to 17.9 +/- 4.1% for younger children, and 6.0 +/- 2.9% to 19.9 +/- 4.9% for older children. Results from the study highlight potential methodological problems which arise in epidemiological studies due to differences between reports from children, parents, and teachers describing childhood emotional and behavioural problems.
Assessment of codependency behavior in two health student groups.
The present study examines the relationship between codependency and caregiving to determine whether codependent persons tend to be attracted to caregiving professions. The study also examined the relationship between codependency, self-esteem, and locus of control, as measured by the Friel Co-Dependency Assessment Inventory (Friel, 1985; Friel & Friel, 1987), the Tennessee Self-Concept Scale (Fitts, 1965), and the Internal-External Locus of Control Scale (Rotter, 1966), respectively. Voluntary participants consisted of 15 occupational therapy students and 15 health information administration (HIA) students believed to be different from one another with respect to the caregiving aspects of their respective professions. The occupational therapy group scored significantly lower than the HIA group on the measure of codependency (m = 21.2 vs. m = 28.8, respectively) [t(28) = 2.258, p = 05]. No other significant differences were noted between groups for the other test scores. Only codependency scores between 31 and 60, that is, moderate-to-severe and severe concerns (n = 6), had a strong correlation with self-esteem scores (r = -.974) and a moderate correlation with locus of control scores (r = .683). No student in the occupational therapy group scored within the moderate-to-severe or severe range. The results did not support a relationship between codependency and choice of a caregiving-oriented profession. Further, only moderate-to-severe and severe codependency scores were indicative of low self-esteem and high external locus of control. Implications of this study suggest incorporation into the academic preparation of occupational therapy students information regarding codependency and self-assessment of codependency to facilitate awareness of the student's need to nurture others.(ABSTRACT TRUNCATED AT 250 WORDS)
Lymphocyte macrophage interactions: peripolesis of human alveolar macrophages.
Peripolesis is a phenomenon in which a lymphocyte attaches itself to another cell, usually a macrophage or veiled cell, and proceeds to circle around it. In emperipolesis, a related phenomenon, the lymphocyte invaginates the target cell so deeply that it appears to be intracytoplasmic. Lung cells in bronchoalveolar lavage fluids from 20 patients were observed in the living state and filmed. Peripolesis of the alveolar macrophages was recorded in six cases. These patients included one case each of carcinoma of the bronchus, tuberculosis, sarcoidosis and asthma, while two patients had no detectable lung disease. Five out of the six positive cases were females. In every instance there was a high number of lymphocytes in the washing. The peripolesed macrophages were not injured, but temporary alteration of the cell membrane was noted in a minority of film sequences. The peripolesing cells were also examined by transmission and scanning electron microscopy. The lymphocyte was found to be closely attached to the surface of the macrophage, with no invagination and its ultrastructure was that of a small lymphocyte. Peripolesis is probably a physiological mechanism concerned with regulation of the immune response in the lung.
Feedback regulation of collagen gene expression: a Trojan horse approach.
The mechanisms involved in feedback regulation of type I procollagen synthesis by the N-terminal propeptide of the pro alpha 1(I) chain, termed Col 1, are poorly understood. We have constructed a metallothionein-human collagen chimeric minigene (pMTCol) that codes for a Col 1 fusion protein but lacks a signal peptide sequence and, therefore, would be expected to direct the synthesis of the fusion protein to the cytosol. Baby hamster kidney cells and fetal calf ligament cells, transfected with pMTCol, transcribed the gene and synthesized an intracellular antigen that was identified as the fusion protein with a monospecific antibody. Transfected fetal calf ligament fibroblasts showed significantly reduced levels of endogenously produced type I collagen, as determined by imaging and digital quantitation of immunofluorescence by confocal microscopy; synthesis of fibronectin, thrombospondin, and SPARC (secreted protein, acidic and rich in cysteine) was unchanged or increased in these cells. This recombinant approach offers the potential for a systematic analysis of feedback regulation of collagen synthesis.
Nursing: an intellectual activity.
Explore the source record for details and available documents.