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Biomedical subjects

G M White

Publications and source records attributed to G M White.

At least 19 recordsLinked to original sources
PubMed1992

Cyclosporine therapy for psoriasis: a cell cycle-derived dosing schedule.

BACKGROUND: Cyclosporine is effective in the treatment of psoriasis; however, potentially serious side effects limit its long-term use. On the basis of the 36-hour psoriatic keratinocyte cell cycle, a new dosing regimen was investigated. OBJECTIVE: The purpose of this study was to evaluate a 36-hour weekly dosing schedule with cyclosporine for the treatment of psoriasis, in an attempt to decrease side effects while maintaining efficacy. METHODS: Fifteen patients were studied by means of oral doses of cyclosporine taken at 12-hour intervals for three doses per week during a 10-week period. The initial dose, 2.5 mg/kg/dose (7.5 mg/kg/wk), was increased every 2 weeks by 2.5 mg/kg/dose to a maximum of 10 mg/kg/dose. RESULTS: The average improvement as assessed by the Psoriasis Area and Severity Index for all 15 patients was 61%. Six patients had a more than 75% improvement, three patients improved 50% to 74%, and six patients improved less than 50%. Three patients dropped out because of adverse side effects, and three others completed the study at a reduced dose. CONCLUSION: It is concluded that, although effective, this dosing regimen may not have an advantage over daily dosing, given its side effect profile and the need to go to relatively high doses every 24 hours.

Adult↗
PubMed1991

Signet ring cell basal cell carcinoma.

A 63-year-old man presented with a signet ring cell basal cell carcinoma of the right infraorbital area. This is the third reported case of this rare variant of basal cell carcinoma characterized by tumor cells containing large, hyalinized, eccentric, intracytoplasmic inclusions that compress nuclei into crescent or ring-shaped forms. Antibodies to both high and low molecular weight cytokeratins were strongly positive, staining the inclusions in a uniform fashion. Vimentin and actin antibodies did not stain the inclusions. These results support previous electron microscopic studies that show the inclusions to be aggregates of intermediate filaments blending into tonofilaments at their periphery. Although speculative, the formation of signet ring cells does not appear to be a degenerative or necrotic phenomenon, but probably a peculiar aberrant form of individual cell keratinization.

Basal Cell Carcinoma↗
PubMed1991

Scanning acoustic microscopy of neoplastic and inflammatory cutaneous tissue specimens.

Acoustic microscopy utilizes high frequency ultrasound to generate microscopic images. The current study was designed to examine representative disorders of the skin by use of a reflective scanning acoustic microscope (R-SAM), and to determine whether the obtainable resolution was sufficient to render a microscopic diagnosis. An Olympus UH3 Scanning Acoustic Microscope was utilized with lenses producing burst wave frequencies at 600 and 800 MHz (600 and 800 million cylces/sec). Cutaneous tissue specimens representing 12 different neoplastic and inflammatory disorders were examined. Acoustic images of unstained sections were compared with conventional light microscopic study of sections stained with hematoxylin-eosin. In most neoplasms examined, it was possible to make a specific diagnosis primarily from low magnification pattern analysis. Although individual cells could be visualized, cytologic atypia was poorly defined. In the inflammatory disorders, a specific diagnosis was possible in all but bullous pemphigoid and lichen planus, because the composition of the inflammatory infiltrate was difficult to determine. The advantages of the R-SAM include the capability of producing an acoustic profile of the tissue and the future possibility of in situ diagnosis.

Humans↗
PubMed1987

Personal reflections on the nature of intelligence in humans and machines.

Computers, the human mind, and social systems have common problems of inadequate memory and insufficient data manipulation speed. In each of these domains, information compression techniques have evolved to reduce storage and processing needs. Among the techniques for information compression, coding of information in procedures stands out as exceptionally powerful. Procedural information coding also gives rise to behavior that may be defined as intelligent. It is found in the human mind, in machines and in social systems. Its use in human thought is aided by language development which promotes regular review of abstract procedures. A practical consequence of better understanding of procedural information coding is the possibility of training people to exhibit greater mental capacity, a controversial possibility. This paper explores the impact of data processing resource limitations, data compression and procedural thinking in men and machines.

Artificial Intelligence↗
PubMed1987

Urinary obstruction in azotemic patients: detection by sonography.

Renal sonography is frequently requested in patients with an elevated or rising creatinine, often with the instruction to "rule out obstruction." A prospective study of patients undergoing renal sonography for newly discovered azotemia (creatinine greater than 1.8 mg/dl) or worsening renal failure was undertaken to evaluate the clinical utility of the sonographic examination. Patients with known obstructive uropathy, renal calculi, renal mass, or hematuria were excluded. In 189 patients, 17 (9%) had hydronephrosis: 11 unilateral (one with a solitary kidney) and six bilateral. Obstructive causes were subsequently established in the solitary kidney and in four patients with bilateral dilatation. These five patients (2.6%) with clinically significant hydronephrosis were shown subsequently to have a clinical history that strongly suggested the presence of urinary tract obstruction. Our data suggest that, in patients without a clinical history that suggests obstruction (such as calculi, bladder outlet obstruction, or pelvic mass), the likelihood of finding bilateral hydronephrosis by sonography is small.

Humans↗
PubMed1987

Nonunion of the humeral shaft.

Retrospective review of records of 26 patients with nonunion of the humeral shaft revealed several factors frequently associated with the development of nonunion. The fractures were transverse and short oblique and treated per primam with hanging casts or open reduction. Surgical fixation was unstable. The types of nonunion were atrophic in 19 patients, hypertrophic in five patients, and synovial pseudarthrosis in two patients. Twenty-four of 26 nonunions (92%) treated with bone grafts and rigid internal fixation healed in an average of 5.6 months. Overall, 47 surgical procedures, including prior procedures, were performed on these 26 nonunions. The average number of operations per patient was 1.8. Successful platings produced immobilization, consisting of an average of 6.8 points of cortical fixation above the nonunion and 7.1 cortices below. Rigid fixation was not obtained in the unsuccessful procedures. Unsuccessful platings were noted to have unstable fixation, with an average of 2.7 points of cortical fixation above the nonunion and 3.0 cortices below. Bone grafting was performed in only 55% of the unsuccessful platings. Optimal treatment of nonunions of the humeral shaft consists of resecting atrophic nonunions, shortening the bones, drilling sclerotic areas, and apposing bleeding diaphyseal surfaces; open reduction with internal fixation with a broad compression plate, including at least six points of cortical fixation above and below the nonunion; compression of the nonunion by means of interfragmentary lag screws, prestressing of the plate, dynamic compression by the plate, or direct compression by the external compression device; and autogeneic cancellous iliac bone grafts.

Adolescent↗
PubMed1986

Ligamentous avulsion of the ulnar collateral ligament of the thumb of a child.

Ulnar collateral ligament ruptures of the metacarpophalangeal joint of the thumb in children are usually associated with epiphyseal fractures of the proximal phalanx and, less frequently, cartilaginous fragments from the metacarpal. Radiographs are often normal. We describe an isolated ligamentous avulsion of the ulnar collateral ligament from the thumb metacarpal, without a bony or cartilaginous fragment, in a skeletally immature 12-year-old boy.

Child↗