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Biomedical subjects

T Johnson

Publications and source records attributed to T Johnson.

At least 19 recordsLinked to original sources
PubMed1992

Early intervention in psychiatric emergencies: a controlled clinical trial.

In the UK, psychiatric care of patients with acute and chronic disorders has increasingly moved from hospital to the community. We have evaluated in a controlled trial patients with severe mental illness, who were assigned to early intervention by community services or to standard hospital treatment. 100 patients aged 16 to 65 years presenting as psychiatric emergencies to an inner London teaching hospital were randomly allocated to a multidisciplinary community-based team (n = 48) or conventional hospital-based psychiatric services (n = 52) and assessed over a 3-month period. Ratings of psychopathology and social functioning were made before treatment and after 2, 4, and 12 weeks by independent assessors. 85 patients completed all assessments, and all patients had evaluable data beyond 2 weeks. 3 patients died during the study, 2 from natural causes and 1 from an accident. Patients referred to the community service showed greater improvement in symptoms and were more satisfied with services than those in the hospital-based service. Patients treated in the hospital-based service spent eight times as many days as psychiatric inpatients as those treated in the community-based service. Patients both prefer and seem to benefit from community-based psychiatric care, and our early-intervention community service might be a good model for such care.

Adolescent↗
PubMed1992

Immunoglobulin V gene expression in CD5 B-cell malignancies.

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphomas (SLL) generally are malignancies of CD5 B cells. Immunophenotypic and clinicopathologic data, however, are required to distinguish subtypes that apparently have a different cytogenesis than that of conventional CLL or SLL. In addition to expressing CD5, neoplastic cells of the latter are also distinctive in that they frequently coexpress surface immunoglobulin (Ig), bearing one or more cross-reactive idiotypes (CRIs) (e.g. 17.109, G6,) that commonly are found on monoclonal IgM autoantibodies. The frequent occurrence of such CRIs reflects both the biased rearrangement and subsequent selected expression of Ig V genes with little or no somatic mutation. IgM/L CLL, for example, frequently (8/33) harbor abortive Ig rearrangements involving Humkv325, the VK gene encoding the 17.109-CRI. Also, the VH1 gene(s) encoding the G6 CRI accounts for over 10% of all VH genes and over 60% of all the VH1 genes used in randomly selected common CLL/SLL. Furthermore, comparison with the Ig expressed by nonmalignant G6 CRI+ B cells reveals an apparent restriction in the CDR3 of IgH expressed by G6 CRI+ CLL. Coupled with the observed potential bias in antibody light chain and heavy chain pairing in B-CLL, these data suggest that the autoantibodies expressed in this disease are selected based on antigen-binding activity. Collectively, our studies indicate that nonstochastic Ig V gene rearrangement and subsequent selection may influence the Ig repertoire expressed in this common B-cell malignancy.

Animals↗
PubMed1992

Bringing parents into school clinics: parent attitudes toward school clinics and contraception.

Prior to implementing a change in school clinic policy to allow dispensing of contraceptives, parents of school-based clinic (SBC) enrollees were surveyed regarding attitudes toward clinic quality of care, desired services, and contraceptive distribution. Telephone interviews were conducted with a systematic sample of 262 parents who normally are in charge of the adolescent's health care. Parental opinion was felt to be crucial in shaping Baltimore SBC contraception policy. Parents overwhelmingly endorsed current clinic services including family planning for sexually active teens, annual physicals, and drug and alcohol counseling. Most parents rated the SBC as excellent (25%) or very good (36%), although a substantial minority found it difficult to rate the clinics (27%, "don't know"). Parents with prior verbal contact (45%) were more likely to rate the clinic as excellent (35% versus 16%) and less likely to respond "don't know" (13% versus 38%, p less than 0.001). Parent attitudes toward contraception was context specific: 63% endorsed and 27-30% opposed prescribing and dispensing. If a boy (or girl) was already having sex, 76% (or 75%) of parents supported and 14% (or 17%) opposed providing birth control pills or condoms. With parental permission, 93% supported contraception and only 3% were opposed. No differences were found by age, race, gender, or grade of student. Prior verbal communication with the clinic did not affect parent attitudes toward contraception. Consideration of parent attitudes was critical to changing SBC contraceptive dispensing policy in Baltimore. Contraceptive distribution, after counseling and necessary medical care, was initiated in September 1990. The parent and community response has been very supportive.

Adolescent↗
PubMed1992

Continuous flow solid (gel) phase peptide synthesis using unsupported ultra-high load polymers.

A simple, manually operated, continuous flow apparatus is described for solid (gel) phase peptide synthesis. The approach uses an unsupported phenolic bead form core network at an initial matrix loading of 5 mmol g-1, the theoretical maximum. The synthesis is performed in a flow reactor under low pressure conditions. "Layered displacement" of reagent solutions and washing solvents is an essential feature that has been developed to facilitate efficient peptide synthesis. The usefulness of the present system in conjunction with N alpha Boc protected amino acids is illustrated by the syntheses of [Leu5]-enkephalin and dermorphin. The potential for scale up synthesis has also been investigated.

Amino Acid Sequence↗
PubMed1992

The teacher's role in facilitating memory and study strategy development in the elementary school classroom.

The efforts of 69 elementary school teachers to instruct children in cognitive processing activities were observed. Although the teaching of such activities was relatively infrequent, it varied by grade (occurring more often in grades 2-3 than in higher or lower grades) and by the content of instruction. Teachers of grade 4 and above more often provided rationales for the use of cognitive strategies than did teachers of younger children. In a second study, children of three achievement levels were selected from classrooms in which teachers varied in their use of suggestions regarding cognitive processes. Subsequent to training in the use of a memory strategy, children's performance on a maintenance trial was evaluated: Among average and low achievers, those whose teachers were relatively high in strategy suggestions showed better maintenance and more deliberate use of the trained strategy than did children whose teachers rarely made strategy suggestions. The role of school experience in the development of children's memory skills is discussed.

Achievement↗
PubMed1992

Corticosteroids in the management of adnexal hemangiomas in infancy and childhood.

Adnexal hemangiomas are common in infancy and childhood. They can be interesting to the ophthalmologist for two reasons: cosmetic and functional (the second, the more important). By their natural history, they can produce serious visual consequences by producing refractive or stimulus-deprivation amblyopia. The management of adnexal hemangiomas is a challenge. The accepted method is most instances is corticosteroid therapy. This is administered either by local, intralesional, or systemic routes; the first is preferred. Steroid therapy can cause systemic and local side effects. Furthermore, a rebound effect can occur with this type of therapy. We present the cases of 12 patients with adnexal hemangiomas treated with steroids. These patients are reviewed, with emphasis on their responses and the complications of steroid therapy.

Betamethasone↗
PubMed1992

Striving for excellence through quality improvement.

Numerous factors are affecting health care services today, including increased consumer awareness; growth of medical technology; rising costs and an unpredictable financial market; a continued shortage of health care professionals, especially nurses; and a shift of many services from inpatient to outpatient settings. As a result, American health care is undergoing rapid change. This article explores how one management concept--quality improvement--can help foster innovative, effective, and efficient change in today's health care organizations.

Humans↗
PubMed1991

Proteoglycans of bovine articular cartilage. The effects of divalent cations on the biochemical properties of link protein.

In cartilage proteoglycan aggregates, link protein stabilizes the binding of proteoglycan monomers to hyaluronate by binding simultaneously to hyaluronate and to the G1 globular domain of proteoglycan monomer core protein. Studies reported here involving metal chelate affinity chromatography demonstrate that link protein is a metalloprotein that binds Zn2+, Ni2+, and Co2+. Zn2+ and Ni2+ decrease the solubility of link protein and result in its precipitation. However, link protein is readily soluble and functional in low ionic strength solvents from which divalent cations have been removed with Chelex 100. These observations make it possible to study the biochemical properties of link protein in low ionic strength, physiologic solvents. Studies were carried out to define the oligomeric state of link protein alone in physiologic solvents, and the transformation in oligomeric state that occurs when link protein binds hyaluronate. Sedimentation equilibrium studies demonstrate that in 0.15 M NaCl, 5 mM EDTA, 50 mM Tris, pH 7, link protein exists as a monomer-hexamer equilibrium controlled by a formation constant of 2 x 10(27) M-5, yielding a delta G' of -36 kcal/mol for the formation of the hexamer from six monomers. On binding hyaluronate oligosaccharides (HA10 or HA12), link protein dissociates to dimer. Link protein hexamer is rendered insoluble by Zn2+. Greater than 90% of the protein is precipitated by 2 mol of Zn2+/mol of link protein monomer. The binding of hyaluronate oligosaccharide by link protein strongly inhibits the precipitation of link protein by Zn2+. The link protein/hyaluronate oligosaccharide complex is completely soluble in the presence of 2 mol of Zn2+/mol of link protein. At higher molar ratios of Zn2+/link protein, the inhibitory effect of hyaluronate oligosaccharide on the precipitation of link protein is gradually overcome. Hyaluronate oligosaccharide is not dissociated from link protein by Zn2+. Hyaluronate remains bound to the link protein which is precipitated by Zn2+, or to the link protein which binds to Zn2(+)-charged iminodiacetate-Sepharose columns. Hyaluronate oligosaccharides and Zn2+ bind to different sites on link protein.

Animals↗
PubMed1991

Local myocardial biochemical and ionic alterations during myocardial ischaemia and reperfusion.

Acute myocardial ischaemia and reperfusion result in a series of inhomogeneous metabolic, ionic and neurohumoral events that explain the associated mechanical and electrical events, including cardiac death. The time course of the hydrolysis of high energy phosphates, the rise in extracellular potassium and the fall in intracellular and extracellular pH induced by acute no-flow ischaemia have been well characterised. However, the time course of the changes in intracellular sodium, calcium and magnesium levels is less clear. It appears that the changes in intracellular calcium may be pivotal to many of the biochemical and electrophysiological changes produced by the abrupt cessation of coronary arterial inflow and the associated interruption of venous washout. Consequently, agents that modify the handling of calcium by the sarcolemma and the sarcoplasmic reticulum have a significant impact on many of the metabolic, ionic and electrical abnormalities characterising acute ischaemia and reperfusion.

Coronary Disease↗
PubMed1990

Bioeconomic dynamics of a fishery modeled as an S-system.

A bioeconomic model of a single species fishery is developed by using a realistic catch-rate function and assuming that a regulatory agency controls exploitation of the fishery by imposing a suitable tax on the catch. The existence of a nontrivial steady state and its stability are examined. The optimal harvesting policy is discussed from the viewpoints of variational calculus and control theory. The fishery is then modeled as an S-system by following the recasting techniques of Savageau and Voit. Numerical examples of the optimal control curves and the yield-effort curves are obtained by executing the ESSYNS algorithm.

Fisheries↗
PubMed1990

Subjective neuroleptic response and treatment outcome under open and double-blind conditions--a preliminary report.

1. A patient's early subjective response to a neuroleptic was recorded in 17 schizophrenic patients following a fixed dose of neuroleptic under both open and double-blind placebo-controlled conditions. 2. High correlations were found between a patient's subjective response at 2.5, 24 and 48 hours after the initial dose, suggesting that the timing of the initial subjective response rating is not critical. 3. The relationship between the psychiatric improvement and subjective response was not significant under double-blind conditions (r = 0.004), while the relationship under the open condition showed a trend towards significance comparable to earlier reports (r = 0.32). 4. The findings question the usefulness of applying early subjective response to a neuroleptic to predict clinical improvement.

Adult↗
PubMed1990

Extensive keloids following hair transplantation.

Hair transplant surgery is a highly successful procedure for improving alopecia. However, this procedure is not without its potential risks and complications. A case of a large keloidal scar following hair transplantation is presented. Those performing hair transplant surgery should be aware of this significant potential complication, especially in Black and Oriental individuals, who are more prone to keloid formation.

Alopecia↗
PubMed1990

Gamma camera image acquisition, display, and processing with the personal microcomputer.

The authors evaluated the potential of a microcomputer for direct acquisition, display, and processing of gamma camera images. Boards for analog-to-digital conversion and image zooming were designed, constructed, and interfaced to the Macintosh II (Apple Computer, Cupertino, Calif). Software was written for processing of single, gated, and time series images. The system was connected to gamma cameras, and its performance was compared with that of dedicated nuclear medicine computers. Data could be acquired from gamma cameras at rates exceeding 200,000 counts per second, with spatial resolution exceeding intrinsic camera resolution. Clinical analysis could be rapidly performed. This system performed better than most dedicated nuclear medicine computers with respect to speed of data acquisition and spatial resolution of images while maintaining full compatibility with the standard image display, hard-copy, and networking formats. It could replace such dedicated systems in the near future as software is refined.

Gamma Cameras↗
PubMed1990

Serum CA 125 levels in early pregnancy and subsequent spontaneous abortion.

CA 125 has been found in high concentrations in human amniotic fluid throughout gestation, with significant quantities seen in the decidua and chorion. Because disruption of the epithelial basement membrane of the fetal membrane or the decidua could theoretically lead to a rise in maternal CA 125 levels, this increase may be a predictor of subsequent spontaneous abortion of the fetus. A study was initiated to investigate whether a sudden rise in the serum CA 125 level might predict spontaneous first-trimester abortions. CA 125 levels of 101 pregnant women were evaluated 18-22 days from conception and 6 weeks from conception (a frequent time for spontaneous abortion) to determine whether there is a sudden increase (from baseline or early trimester levels) during the middle or late first trimester immediately before or at the time of abortion. The results indicated that although there was a definite correlation found between elevation of CA 125 and spontaneous abortion, the higher levels occurred early in the first trimester whereas the majority of abortions did not occur until much later, after fetal viability was established. Six of ten women with CA 125 levels of 150 U/mL or greater aborted, compared with four of 92 women with CA 125 levels less than 150 U/mL. One of 11 women pregnant after in vitro fertilization had a CA 125 level above 150 U/mL, and she aborted.

Abortion, Spontaneous↗
PubMed1989

Selective separation of virus proteins and double-stranded RNAs by SDS-KCl precipitation.

The total viral structural polypeptides and the double-stranded genomic RNAs of bluetongue virus can be selectively separated by a single SDS-KCl precipitation step. This simple, rapid and highly reproducible method enables greater than 95% recovery and purity of both viral proteins and dsRNAs within 30 min. The serotypic identity of the separated dsRNAs can be analyzed by SDS-PAGE electrophorogram immediately. After a single phenol/chloroform extraction, the dsRNA can also be used as hybridization probes, templates for molecular cloning and direct RNA sequencing. The SDS-KCl-precipitated viral proteins could be used readily for peptide mapping and as immunogens. Polyclonal and monoclonal antibodies raised against SDS-KCl-precipitated viral structural polypeptides were useful in Western immunoblots.

Blotting, Northern↗