Biomedical subjects
Publications and source records attributed to D C Smith.
The Simmons sidewinder catheter is frequently used, but reforming its unique curve may be a problem. In our original description, we used the left subclavian artery to reform the catheter's curve. We no longer use this as our primary method of reformation. Our current method, which is simpler, quicker, and more reliably successful, is described.
Operative treatment of critical stenoses of the internal carotid artery secondary to fibromuscular dysplasia has been performed for nearly 2 decades using graduated metal dilators. While percutaneous transluminal balloon angioplasty of the internal carotid via the femoral artery has several advantages over the operative metal dilator method, cerebral embolization is a matter for concern. The authors have performed operative transluminal balloon angioplasty in such cases, permitting backbleeding with removal of any thrombi or debris. This technique combines the advantages of dilatation by a Grüntzig balloon with post-dilatation carotid backbleeding. Five patients have been successfully treated thus far using this technique.
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The research efforts to identify the etiological agent of malarial fevers during the decade 1880-1890 are traced and the various factors which facilitated and retarded research are examined. Alphonse Laveran's original announcement of his observation of the malaria parasite was regarded with great skepticism. This was a result of a rival claim of a bacterial cause of malarial fevers, advanced by Edwin Klebs and Corrado Tommasi-Crudeli, and because of the failure of Laveran's germ to explain the clinical diversity and pathophysiology of malaria. Changes in research technology, particularly the effective use of aniline dye stains, made possible greater precision in the study of the blood of malaria patients and in the subsequent understanding of the asexual phase of the plasmodium life cycle by Ettore Marchiafava and Angelo Celli. Until 1886, however, the study of the plasmodium was confined to a small group of researchers whose work was regarded with considerable reserve by the medical profession. Early in 1886, when Camillo Golgi coordinated the life cycle of the organism with the clinical course of the different types of malarial fever, clinicians became interested in the work. By 1890 Laveran's germ was generally accepted but most of Laveran's initial ideas had been discarded in favor of the taxonomic work and clinical pathology of the Italian school.
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This is the second report on the results of an investigation of the psychosocial correlates of depression in mildly mentally retarded adults. Results of the present study showed that depression was associated with informant ratings of poor social skills. The results of the entire investigation suggest that further research is necessary on the associations among poor social skills, low levels of social support, and the occurrence of depression in mentally retarded adults.
Ten dogs were subjected to total extrinsic cardiac denervation. The negative inotropic responses of their hearts were compared with those of nine normal controls with respect to acetylcholine (ACh; 0.1-1.0 micrograms) and nicotine (0.5-100 micrograms) administered intra-coronary. The dogs were on cardiopulmonary bypass and atrial and ventricular contractility were measured by means of a four-chamber isovolumic technique. At the end of this phase of the experiment, atrial strips were removed for in vitro evaluation of negative inotropic responses to Ach (1 X 10(-8) to 1 X 10(-6) M) and nicotine (1 X 10(-6) to 1 X 10(-4) M). Both in vivo and in vitro methods demonstrated a leftward shift of the dose-response curve for nicotine in denervated hearts, indicative of denervation hypersensitivity. Hypersensitivity to ACh was seen in atria in vitro but not in vivo. An additional 13 dogs were used only for in vitro studies. There was no difference in response between these dogs and those which had been used for both in vivo and in vitro studies. The results support the in vivo observation that the intrinsic cardiac neurons become supersensitive to nicotinic activation after extrinsic denervation. In addition, in vitro testing revealed atrial hypersensitivity to ACh which was not detected by in vivo methods. Inasmuch as the in vivo and the in vitro testing were done on the same animals, a method for determining equivalence for in vivo doses and in vitro concentrations is presented.
Three tumor cell subpopulation lines derived from a single, spontaneously occurring BALB/cfC3H mammary tumor were evaluated for their ability to cause a leukemoid effect in mice. One of the BALB/cfC3H tumor cell lines (410.4) produced leukocytosis with neutrophilia, hypercalcemia, and thymic atrophy. A second line (66) produced none of these effects. The third line (168) was intermediate in its ability to affect neutrophil counts and splenomegaly but did not produce thymic atrophy or hypercalcemia. These studies demonstrated that the hemopoietic effect of tumor cells derived from a single tumor was variable and that a tumor cell line which caused neutrophilia also induced hypercalcemia and thymic atrophy, the same association that was reported previously in the case of murine CE mammary carcinoma. These observations will be useful in the further investigation of pathophysiology of tumor-induced leukemoid reactions, hypercalcemia, and other paraneoplastic syndromes.
A prospective randomized double-blind study was performed to assess the value of a single intravenous injection of 1.5 g cefuroxime in the prevention of wound sepsis after low risk elective cholecystectomy. Wound infection developed in 10 of 81 control patients compared with 2 of 79 treated patients (P less than 0.05). Wound sepsis occurred more commonly in patients with infected bile or with a positive culture from a closing wound swab. Cefuroxime significantly reduced the isolation of staphylococci but not other organisms from the closing wound swab and also produced a significant reduction in wound infection in patients with sterile bile.
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A commercial digital micrometer has been modified mechanically and electronically to allow the measurement, in situ, of the thickness of dental plaque. The device detects initial contact between a moving probe and the plaque, and measures subsequent probe displacement through to the tooth surface. Instrument accuracy is +/- 5 micron over a displacement range of 0-5 mm, with 1 micron resolution. In practice, after a short 'learning' phase, reliable clinical results can be obtained.
Malignant fibrous histiocytoma has been reported as a primary renal tumor in 7 cases, of which 4 had relevant clinical histories and followup. We report an additional case noting, as others have, the similarity in clinical presentation with renal cell carcinoma. Despite a radical operation this tumor often manifests local recurrence with subsequent distant metastases.
Infection with Corynebacterium ulcerans has been previously reported in association with cows' milk. Further evidence that the disease is a zoonosis is given in this report of infection in a consumer of untreated milk. The organism was isolated from a sample of milk, and from two cows in a herd of 93 Jersey cattle. One of the farm workers was a symptomless nasal carrier.
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The wear behavior of 12 commercial restorative composites (conventional and microfilled) and an unfilled restorative material was evaluated using an in vitro wear test referred to as an oscillatory wear test. The effect of varying test conditions was evaluated in a series of preliminary experiments in order to define test conditions for material evaluation. The materials were tested after being aged in water at 37 degrees C for periods of from seven days to one year. The results indicated consistently lower wear rates for the microfilled materials as compared with those of the conventional composites. Aging did not result in significant differences in wear rates measured by this method. Scanning electron micrography of worn surfaces suggested a possible effect of filler particle shape and bonding to the matrix to explain this difference. Although the relevance of the results to clinical behavior is not yet known, the study indicated the importance of material variables on wear.
The reliability of overnight 8-hour infusion cholangiography in confirming the diagnosis of acute cholecystitis or biliary colic was assessed by a prospective study in 100 patients. 55 positive infusion cholangiograms were subsequently confirmed at operation in 45 patients and by cholecystogram in 10 patients who did not have surgical treatment. The absence of false positive examinations is of fundamental importance if early cholecystectomy is to be performed without the risk of an unnecessary laparotomy. Infusion cholangiography proved to be a safe, simple and reliable investigation in the confirmation of acute gall-bladder disease.