Biomedical subjects
Publications and source records attributed to J Black.
A new technique of medullary nailing of the humerus using a screw-headed nail is described. Eighteen patients with two-part fractures of the surgical neck of the humerus were reviewed. Fifteen had satisfactory results while three were unsatisfactory. Nine patients with fractures of the shaft of the humerus were also treated with satisfactory results in eight. Three patients with non-union of the humerus had unsatisfactory results.
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Six patients who underwent bilateral nephrectomy for renal carcinoma were placed on maintenance dialysis; of these, 1 patient had a renal transplant. A 5-year 44% survival of these patients was observed. We feel that radical nephrectomy followed by chronic dialysis is a reasonable alternative and offers a fair prognosis to patients with bilateral renal cancer in which partial nephrectomy is not possible.
Tissue plasminogen activator (t-PA) and/or pro-urokinase (pro-UK) induced lysis of standard 125I-fibrin clots suspended in plasma was studied. Doses were kept below the concentration at which a nonspecific effect was seen, i.e., where fibrinogenolysis and major plasminogen consumption were observed. Small amounts of t-PA potentiated clot lysis by pro-UK by attenuating the lag phase characteristic of pro-UK, and causing a much earlier transition to the rapid phase of lysis. Similar promotion of the fibrinolytic effect of pro-UK was obtained when clots were pretreated with UK or with a little plasmin (less than 1% clot lysis). Promotion by plasmin was nullified by a subsequent treatment of the clot with carboxypeptidase B, indicating that the plasmin effect was related to the exposure of carboxy terminal lysine residues on fibrin. These lysine termini, absent in undegraded fibrin, are known to be essential for the high affinity binding of plasminogen to fibrin. In contrast, clot lysis by t-PA was unaffected by plasmin pretreatment and little affected by carboxypeptidase B treatment of the fibrin substrate. Therefore, plasminogen bound to lysine termini on fibrin, although found to be essential for pro-UK, did not appear to serve as a substrate for t-PA. Selective activation of fibrin bound plasminogen has been attributed to the conformational change in Glu-plasminogen that occurs as a result of binding. The present findings suggest that this conformational change occurs when plasminogen is bound to a terminal lysine but not to an internal lysine. Plasminogen bound to the latter site on fibrin was activated by t-PA and therefore is involved in the ternary complex. This initiates lysis of the undegraded clot and exposes the plasminogen binding sites required by pro-UK. By their complementary activation of fibrin bound plasminogen, t-PA followed by pro-UK induces efficient and synergistic fibrinolysis, whereas each is relatively inefficient when used alone.
A new system of hardware and software has been designed for quantitative high resolution analysis of ground foot pressures during stance and gait. In the system, a large photoelastic sheet is used as the transducer and a computerized video system for analysis and display. This system offers a larger active surface at higher resolution and at lower cost than any other system heretofore described. It will be used to predict diabetic plantar ulceration as well as to detect anatomic and motor defects affecting the feet.
An isoelectricfocusing method has been developed to enable large scale screening of newborn blood for hemoglobinopathies. The method utilizes a thin layer agarose gel containing carrier ampholytes in the pH range 6-8. The gradient is non linear allowing increased resolution in the pH region 6.8-7.8 where most hemoglobin variants are isoelectric. The increased resolution between Hb A and Hb Fac enables screening for beta-thalassemia by densitometric analysis. By calculating the ratio of Hb A/Hb Fac or Hb F/Hb A it is possible to detect newborns heterozygous for beta(+)- or beta(0)-thalassemia. Structural variants, unresolved by other electrophoretic methods, are easily detected. Seventy-two samples can be analyzed on a single gel in 90 minutes. Traces of hemoglobin variants can be detected by a heme-specific stain requiring no destain step.
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The development and implementation of an outpatient prescription formulary in an independent-practice model health maintenance organization (HMO) and the role of the pharmacy and therapeutics (P&T) committee in the process are described. Approximately 600 physicians provide medical care and control the operation of this independent practice association (IPA); of approximately 45,000 members, 95% are eligible for outpatient prescription services provided by one of 188 local pharmacies. The formulary, which is restricted to noninjectable medications, was developed by a P&T committee composed of eight IPA physicians, a representative of the local pharmaceutical association, and three staff members of the IPA's pharmacy department. The printed version of the formulary indexed almost 1800 items and included only commonly used medications to limit its size. Requests for additions or deletions of drugs were evaluated monthly. After a four-month period during which physicians were asked to comply with the formulary, mandatory compliance was imposed, with a limit of 16 nonformulary prescriptions per physician per month being allowed. Based on the results of an informal survey, the physicians indicated that the formulary was relatively easy to adjust to (44.1%), somewhat difficult to work with (43.6%), and somewhat disruptive to their prescribing practices (55.3%). When asked about quality of patient care, 74.3% indicated there was no change. Physician compliance with the formulary system increased from 88.0% to 96.1% after the formulary was mandated by the IPA. Under the direction of the P&T committee, a formulary was implemented effectively in this HMO outpatient prescription drug program.
Information about health concerns of adolescents can assist in assessment and treatment of their particular medical problems. Because teachers are important figures in the lives of young people, their beliefs about student health concerns are often solicited. A survey to assess adolescent health concerns and teachers' beliefs about student health concerns was conducted in two urban high schools on a sample of 831 students and 146 teachers. An assessment of 22 health concerns among the students revealed that a moderate level of concern existed on virtually every issue (the mean percentage "very concerned" was 55%), with black students and girls reporting more concern about many topics. In contrast, teachers significantly underestimated the level of concern of the students by an average of 13%, consistently having inaccurate beliefs about the types and level of student concerns. Students are concerned about health issues and are in need of health education and counseling in these areas. Teachers are not always aware of the level and types of student health concerns and may not be good sources of information about adolescent health.
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A pyrolytic carbon coating was applied to F-75 chromium-cobalt-molybdenum alloy in an effort to reduce the release of corrosion products in vivo. After intramuscular implantation in the rat, a complex pattern of serum and urine concentration elevations of chromium, cobalt, and nickel was seen. The carbon-coated implants released more chromium and cobalt than uncoated controls, as seen by significantly elevated metal concentrations in serum and urine. Animals receiving carbon-coated implants showed a high rate of recurrent implant site inflammation. Neoplastic infiltration of 24 animals with coated implants, but not in any of the 16 animals which received either uncoated F-75 microsphere or poly(ethylene) particulate implants.
We conducted a retrospective review of 21 adult patients with osteomyelitis and septic arthritis who were treated with high doses of oral antimicrobial agents, usually after an initial course of intravenous therapy. The mean duration of parenteral and oral therapy was 3.6 days and 43.0 days, respectively. Absorption of oral antibiotics was assessed by determining the trough serum bactericidal titers for the infecting organism; whenever feasible, the dosages were adjusted to achieve trough titers greater than or equal to 1:8. The follow-up period ranged from six to 66 months (mean, 42.4 months). Eighteen of 21 patients had no clinical signs of recurrence after initial therapy. One patient with an infected joint prosthesis developed recurrent infection, and two patients had recurrences accompanied by sequestra. The mean duration of hospitalization was 13.4 days, and the mean duration of outpatient treatment was 31.9 days.
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