Biomedical subjects
Publications and source records attributed to M Cohen.
A technique for reactivating the Howmedica mini-lengthening device is presented. This procedure, performed in the clinic, allows for mandibular distraction in excess of the standard maximum of 25 mm.
Severe craniofacial synostosis can be a devastating problem for a newborn infant. Reasons for early surgical intervention include cranial stenosis, hydrocephalus, inadequate globe and corneal protection, compromised airway patency, and feeding problems. In this preliminary report, we describe the management of severe craniofacial synostosis in a newborn infant by means of cranial and midfacial distraction osteogenesis.
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From the literature and our own experience, 11 cases of hemorrhage or infarction of a pituitary adenoma associated with cardiac surgery have been identified over a 13-year period. Males outnumbered females by 10 to 1. Symptoms observed were headache, lethargy, confusion, obtundation, unilateral ptosis, meiosis, and opthalmoplegia involving cranial nerves III, IV, and VI, visual field deficits, and hemiparesis. Diagnosis in most recent cases has been confirmed with computerized tomography or magnetic resonance imaging. All patients received adrenocortical steroid therapy initially. Eight patients underwent transsphenoidal hypophysectomy and all survived. One patient underwent decompression craniotomy and died. Intracranial surgery was deferred in 1 patient who survived and in another who died of a massive stroke. Residual neurological deficits were noted to be either absent, minimal, or resolving in 7 of the 9 patients who survived their initial hospitalization. While numerous mechanisms have been proposed to explain the hemorrhage and necrosis of a pituitary adenoma during heart surgery, no direct cause has been clearly identified. Surgical treatment is commonly necessary since untreated pituitary apoplexy is often fatal. Transsphenoidal hypophysectomy with decompression is the preferred method of treatment with a low perioperative mortality and fairly good long-term prognosis.
The early development of medical physics as a separate discipline and profession is briefly reviewed. Although both x rays and radioactivity were discovered by physicists, at first the physical investigations of these phenomena, and their medical applications, proceeded along parallel but independent lines. Radiological journals were founded in Britain, Germany, and the U.S. as early as 1896-1897 but it was not until ten years later that papers on radiation physics began to appear regularly. In 1913 the first full-time physicists were appointed to posts in medical schools and hospitals: William Duane in the U.S. and Sydney Russ in Britain. Thereafter the number of physicists engaged in medical applications increased slowly but steadily, and in the 1920s they began to apply the new science of radiation dosimetry to both x ray and radium therapy. The "Hospital Physicists' Association" was founded in Britain in 1943 with 53 members and the "American Association of Physicists in Medicine" followed in 1958 with 127 charter members.
A single page, handwritten document was discovered when the Macdonald Physics building of McGill University in Montreal was gutted in 1978. This proved to be the draft of Ernest Rutherford's curriculum vitae (C.V.) covering the years 1894-1907, probably written in the autumn of 1906 when Rutherford was preparing to leave McGill. The C.V. contains 21 headings in chronological order, referring to research and other activities of Rutherford and his coauthors (especially Soddy and Barnes), plus a further set of headings relating to the associated investigations of Rutherford's team, including Eve and Hahn. A transcript of the document is provided, although in several places, Rutherford's handwriting is difficult to interpret, and the significance of his abbreviations is not always clear. Each of the items in the C.V. is discussed briefly in this review, in the light both of Rutherford's personal career and of the contribution of his team to the development and understanding of radioactivity. This contribution included the cause and nature of radioactivity (with Soddy), energy aspects of radioactive decay (with Barnes), elucidation of the uranium-radium, thorium and actinium series (Godlewski and Hahn), the radioactivity of the earth and atmosphere (Eve), the nature of the gamma rays (Eve) and, perhaps most important of all, the nature and properties of the alpha particle (Rutherford himself). The latter investigations led directly to Rutherford's later work in Manchester, including the nuclear model of the atom and artificial disintegration of the nucleus.
We compared the ability of direct immunofluorescent staining (DFA) and the PCR to detect Treponema pallidum in specimens from patients with genital ulcer disease. Touch preparations from 156 patients with genital lesions were fixed in acetone and stained with a fluorescein-labeled monoclonal antibody specific for the 37-kDa antigen of T. pallidum. After microscopic examination, the smear was removed from the slide with a swab. DNA was extracted with phenol-chloroform and precipitated with isopropanol. Ten microliters of the extracted DNA was amplified by PCR using primers for the gene encoding the 47-kDa protein of T. pallidum and hybridized to an internal probe. Twenty-two of 156 specimens were positive for T. pallidum by DFA and PCR, while 127 were negative by both methods, yielding a concordance of 95.5% (kappa = 0.84). Four specimens were positive by PCR and negative by DFA, while three specimens were negative by PCR and positive by DFA. The DFA-negative, PCR-positive specimens may have resulted from the presence of large numbers of leukocytes on the slides, obscuring visualization of treponemes. The DFA-positive, PCR-negative results were not due to inhibition of the PCR since purified T. pallidum DNA was amplified when added to aliquots of these specimens. Negative results in these specimens were most likely due to inefficient recovery of their DNA. These data suggest that DFA and PCR are equivalent methods for detection of T. pallidum on touch preparations of genital lesions. Further refinements of the PCR assay are necessary for it to significantly improve the detection of T. pallidum in genital lesions.
Polarized epithelial cells internalize molecules from both apical and basolateral (BL) plasma membrane (PM) domains via receptor-mediated endocytosis. In the kidney, low-molecular-weight proteins (LMWP) are internalized across the apical membrane of proximal tubule cells and degraded in lysosomes. Although indirect evidence suggests some uptake may occur at the BL surface, in vivo studies performed in rats suggest little if any LMWP uptake occurs at the BL surface. The studies presented here showed that native human beta 2-microglobulin (beta 2M) was internalized across the apical surface and followed the same intracellular pathway in the proximal tubule-derived cell line LLC-PK1 as that described in vivo. Either 125I- or gold-labeled beta 2M (125I-beta 2M and gold-beta 2M) bound specifically and reversibly to the apical surface of confluent LLC-PK1 cells. These results were qualitatively similar to previously documented in vivo results. Subsequently, using gold-beta 2M and LLC-PK1 cells grown on porous supports, we showed that a functional uptake system for the LMWP beta 2M was present at the BL surface. Finally, using different-size gold particles conjugated to beta 2M applied simultaneously to the apical and BL surfaces, we observed that apical and BL endocytic routes converged in multivesicular acid phosphatase-negative endosomal structures. Taken together, these data imply that beta 2M can be internalized across both apical and BL domains and that the two pathways converge at a multivesicular level within the endosomal pathway.
OBJECTIVE: Experts do not agree on what, if any, relationships exist between diagnosis, symptomatology, work skills, and the future vocational performance of persons with severe mental illness. The objective of this study was to longitudinally examine such relationships, using a sample of clients who were attending psychosocial rehabilitation programs. METHODS: Subjects were 275 clients of three psychosocial rehabilitation programs who had expressed a vocational goal. They were assessed at intake into the study and then quarterly until they left the rehabilitation program. The variables examined included symptoms, measured by the Brief Psychiatric Rating Scale; diagnosis; work skills, measured by the Griffiths Work Behavior Scale; and vocational status at end-point. RESULTS: Among subjects remaining in the study for one year, both symptomatology and work skills improved significantly. Moderately significant negative correlations were found between symptoms and work skills; subjects who became employed had lower symptom scores and higher work skills than persons who never became employed. CONCLUSIONS: Although a moderate relationship was found between symptomatology and work skills, symptoms should not be considered a proxy measure for vocational functioning among persons with severe mental illness. Participation in psychosocial rehabilitation programs appeared to have a salutary effect on symptoms and work skills.
Therapeutic manipulation of the neck has been shown to produced injury to the vertebral artery. The clinical syndromes produced by this arterial insufficiency generally reflect dysfunction of the brainstem or cerebellum. The authors present a case of such injury that presented with clinical findings, namely, hemiparesis and aphasia, suggestive of involvement of the dominant middle cerebral artery. These findings may have been the result of disruption of flow through the posterior cerebral artery to the thalamus, internal capsule, and cerebral peduncles.
Health care social work has made important progress in developing methods for assuring and improving the quality of services provided, using tools such as computerized information systems. This paper presents a case study demonstrating utilization of preliminary data generated by such a system, focusing on problem identification and professional interventions. Successive stages in the process of data application are described: definition of quality assurance issues; validation of data; hypothesis formation; in-depth analysis through case examples; and formation of change strategies. Results of the application and its implications for practice are discussed.
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The majority of open myelomeningocele defects are small enough that following the neural repair, soft tissue closure is achieved by simple undermining of the skin edges and tension-free approximation in the midline. The larger defects, greater than 5 cm diameter, cannot be closed reliably by simple skin undermining. Such larger defects call for a close cooperation between the neurosurgeon and the plastic surgeon. In the authors' experience, a reliable, safe method of reconstruction of thoracolumbar and lumbosacral meningomyelocele defects involves the en bloc medial advancement of latissimus dorsi and gluteus maximus musculocutaneous units and reapproximation in the midline. This is the authors' preferred method for all medium and large size defects greater than 5 cm in diameter. This method permits primary closure of the defect in three layers. The flaps are based on the thoracodorsal and superior gluteal vessels and the intervening thoracolumbar fascia. This method provides a tension-free, durable, and viable soft tissue coverage over the dural repair. The flaps do not alter the nerve supply of the muscles involved and merely redefine the muscle origins, without compromising muscle function.
Management of malignant upper-extremity tumors is a complex process that should be carried out using all the resources at the disposal of the patient and the surgeon. This article focuses on diagnosis, evaluation, pathology, and treatment.
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