Biomedical subjects
Publications and source records attributed to J Boss.
A 3 x 4 cm breast mass in a 38-year-old woman was surgically removed and was found to be an echinococcal cyst; thorough investigation failed to reveal any other hydatid cysts. Echinococcal cyst should be considered in the differential diagnosis of the much more common malignant breast mass.
A 16-yr-old girl presented with osteomyelitis and massive rectal bleeding. Colonoscopy revealed severe nonspecific colitis. Multiple laboratory investigations failed to disclose the etiology of either the bone or colon infections. Empiric treatment with corticosteroids and sulfasalazine resulted in only transient improvement. One month after discharge, her original symptoms recurred. Blood and pus cultures at this time yielded Brucella melitensis. After tetracycline treatment, the patient recovered. At 1-yr follow-up, she was found completely asymptomatic. Although osteomyelitis is a well-known manifestation of brucellosis, colitis related to this agent has so far not been described.
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Histoplasmosis is a well-known infectious disease that can sometimes run a mysterious and unexpected course. A case is reported that presented as a chronic renal process, with right pyelocutaneous fistula and prolonged purulent discharge as well as focal calcifications of the left kidney with recurrent stone formation. Histopathologic examination of the right kidney, removed in 1975, showed noncaseating granulomas, but the precise diagnosis was not made until 1983, when histopathologic re-examination followed partial resection of the left kidney, for recurrent stone formation. This article emphasizes the difficulty in diagnosing a noncaseating granulomatous disease in general and histoplasmosis in particular, especially when the urogenital tract is involved, with isolated local manifestations. It underlines the progressive and damaging character of this chronic disease, the variety of its manifestations, and attempts to increase awareness of this potentially treatable disease.
Liposarcomas of the larynx are very rare. Only nine cases appear to have been recorded in the English literature. An additional case of liposarcoma of the larynx occurring in a young patient is reported and the relevant literature discussed.
A long-term goal of spine surgeons has been to reduce the morbidity, cost, and recuperative period of primary lumbar disc surgery. In this paper, microdiscectomy and chemonucleolysis are evaluated and compared with respect to achieving these goals. Two groups of successive, noncompensation patients numbering 50 each were studied. All patients met standard clinical and imaging criteria for an isolated lumbar vertebral disk herniation. One group was treated with chemonucleolysis and the second with micodiscectomy. Average follow-up exceeded 3 years. While both treatment groups achieved the stated goal when compared with traditional laminectomy, the microdiscectomy groups demonstrated statistically superior treatment results, with reduced time to return to work, and fewer required subsequent surgical procedures.
In a variety of structural forms, carbon possesses certain properties that render it suitable for implantation in the human body. This report analyzes biocompatibility of a new carbon-carbon prosthesis following long-term middle ear implantation in a prospective, controlled animal study. The prosthesis was placed in the left ear of 20 healthy guinea pigs and in the dorsal subcutaneous tissues for control. The right ear also served as control. Preoperative and postoperative auditory evoked potentials were recorded and compared. Samples of tissue from all three sites were evaluated at 3 and 6 months by light microscopy. The implants also were evaluated by scanning electron microscopy. Samples of lymph nodes, liver, spleen, and lungs also were examined. Fourteen animals (70%) demonstrated no change in auditory evoked potentials postoperatively. One animal developed unilateral dysfunction and three others developed bilateral dysfunction for unexplained reasons. No significant tissue destruction or inflammation of the tissues and no digestion or erosion of the implants were observed. No passage of carbon particles into the reticuloendothelial system was identified. These preliminary results suggest that this new carbon-carbon prosthesis may be biocompatible at 6 months follow-up in the guinea pig and encourage further investigation.
Composites are made of two or more different components that combine their properties into a new material. By modifying the type or structure or volume of the components, a theoretically endless number of new materials can be produced and their properties can be altered as desired. A composite hip implant made of carbon fiber and polysulfone is described.
A variety of synthetic fibrillar ligaments are being developed and clinically investigated. The tissue response to the variety of polymeric fibrils is similar. The soft-tissue response to carbon fiber braid substituting for lateral collateral ligament in three human knees and for the anterior cruciate ligament in one was examined 12-42 months after surgery. An advanced stage of maturity of the composite structure was particularly evident by dense bundles of collagen in one of the collateral ligaments and in the substitute for the anterior cruciate ligament. Associated with the newly formed collagen the carbon fibril initially formed unique carbon collagen of composite structural units. Eventually, subsidence of the fibroblast response was accompanied by an increase in density and width of the collagen fibers and by a loss of the configuration of the carbon-collagen units. Even the mature collagenous structure was not comparable to the natural ligament.
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The soft tissue response to carbon fibre was studied histologically one and a half years after being used to reconstruct the lateral collateral ligament of the human knee. A remarkably consistent pattern was seen in the induced ligament. The basic pattern was a "composite unit", consisting of a core of carbon fibre enveloped in a concentric manner by coherent layers of fibroblasts and collagen fibres. This new structure seemed to have been induced by continuous irritation caused by the physical structure of the carbon fibres; it is unlikely ever to acquire the structure of a natural ligament. However, it is biologically compatible and is biomechanically sufficient as long as the entire tow of carbon fibres is preserved.
Implantation of carbon fiber tow (CFT) for ligament and tendon augmentation was investigated in ten dogs and 45 patients. CFT produced a new structure with a remarkably consistent structural pattern. The basic pattern of the CFT-augmented unit consisted of a core of carbon fiber surround by concentric layers of fibroblasts and collagen fibers. This unit structure was developed from continuous irritation of physical structure of the carbon fiber. In dogs, ultimate tensile strength of the augmented tendon one year after surgery averaged 88% of natural tendon. Digestion of the connective tissue component of the CFT unit exposed the original carbon fiber tow. The connective tissue-free CFT maintained its original tensile strength. The continuous production of collagenous tissue surrounding carbon fibers produced a ligamentous structure that was physiologically compatible and biomechanically sufficient.
Children with Down's syndrome (DS) often have small and abnormal thymuses, with lymphocyte depletion, diminution of the cortex, and loss of corticomedullary demarcation--a picture resembling thymic involution. Besides this, they have markedly enlarged Hassall's corpuscles, some surrounded by a sheath of lymphocytes. Patients with DS are known to have increased numbers of respiratory infections; they also have a higher incidence of lymphatic leukemia than do individuals who do not have DS. Studies of cell-mediated (thymic-dependent) immunity demonstrate that children with DS have both diminished numbers of T cells as well as functional deficiency of these cells.
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A method is described for the study of the surface structure of mammalian chromosomes. Densitometric analysis of scanning electron micrographs permits the detection of regularities where overlying material obscures these in directly inspected micrographs. The method has been applied to the study of mammalian chromosomes.
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