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Biomedical subjects

J Kosek

Publications and source records attributed to J Kosek.

At least 37 records · Page 2Linked to original sources
PubMed1988

Gastrointestinal manifestations of essential mixed cryoglobulinemia.

A patient with essential mixed cryoglobulinemia (EMC) presented initially with gastric ulcers and, six months later, with a lesion of the ileum, mild stricture of the transverse colon, and stricture of the sigmoid colon with deep ulceration. The initial diagnosis was Crohn's disease, but pathologic examination of the resected sigmoid lesion showed vasculitis secondary to EMC. Patients with EMC can present with gastrointestinal manifestations mimicking Crohn's disease. A review and classification of the gastrointestinal manifestations of EMC are presented.

Adult↗
PubMed1986

The interaction between excimer laser energy and vascular tissue.

The effects of XeF1 excimer laser on isolated normal and atherosclerotic aorta were studied. Experiments were performed in flowing water at constant temperature, flow rate, water depth, pulse width (10 nsec), wavelength (351 nm), beam size (1 mm2) and focal length (50 cm). The number of pulses, the pulse energy, and the pulse frequency were varied, and the vascular tissue was studied histologically. The following observations were made: tissue ablation required a minimum threshold pulse energy and was nonlinearly proportional to the number of pulses and the pulse energy delivered; precise tissue ablation occurred at low pulse frequencies, but changes resembling a thermal process were seen as pulse frequency increased; calcified plaque was more photoresistant than atheroma or normal vessel; excimer laser energy was markedly attenuated by blood; and the time interval between pulses and high peak power are related to the precision of ablation by pulsed excimer laser. It is concluded that excimer laser can rapidly and precisely ablate vascular tissue by a photothermal process.

Aorta↗
PubMed1985

Selective absorption of ultraviolet laser energy by human atherosclerotic plaque treated with tetracycline.

Tetracycline is an antibiotic that absorbs ultraviolet light at 355 nm and preferentially binds to atherosclerotic plaque both in vitro and in vivo. Tetracycline-treated human cadaveric aorta was compared with untreated aorta using several techniques: absorptive spectrophotometry, which demonstrated a distinct absorptive peak at 355 nm in tetracycline-treated plaque that was absent in treated normal vessel; ultraviolet microscopy, which showed that treated atheroma acquired the characteristic fluorescence of tetracycline under ultraviolet light; and tissue uptake of radiolabeled tetracycline, which showed 4-fold greater uptake by atheroma than by normal vessel. In addition, intravenous tetracycline administered to patients undergoing vascular surgery demonstrated characteristic fluorescence in surgically excised diseased arteries. Because of tetracycline's unique properties, we exposed tetracycline-treated and untreated aorta to ultraviolet laser radiation at a wavelength of 355 nm. We found enhanced ablation of tetracycline-treated atheroma compared with untreated atheroma. The plaque ablation caused by ultraviolet laser radiation was twice as extensive in tetracycline-treated vs nontreated plaque (2.2 +/- 0.25 mm vs 1.3 +/- 0.55 mm, p less than 0.017). This study demonstrates the potential of tetracycline plaque enhancement for the selective destruction of atheroma by ultraviolet laser radiation.

Absorption↗
PubMed1985

Dual-energy projection radiography in the evaluation of femoral neck strength, density, and mineralization.

Two different dual-energy projection radiography techniques were utilized in an attempt to predict femoral neck strength, bone density, and bone mineral content in 19 pairs of cadaver specimens. Positive simple linear correlation was observed between dual-energy scanned projection measurements and dry density, ash fraction, cross-sectional cortical bone area and, to a lesser degree, force required for fracture, but not trabecular bone volume, failure time, or Singh trabecular grade. Dual-energy film radiography was found to be a less reliable indicator of femoral neck strength, density, and mineral content. Dual-energy scanned projection results related linearly to mineral-equivalent solution (K2HPO4) concentration, and demonstrated long-term reproducibility in repeated specimen studies. Correction factors derived to account for differences in femoral size and rotation were shown to be reliable over a moderate range of neck projections. Although bone mineral measurement at other sites may provide comparable or greater information concerning hip fracture risk, dual-energy scanned projection radiography appears to be a useful technique for assessment of bone density, mineral content, and strength in the femoral neck.

Absorptiometry, Photon↗
PubMed1985

Enrichment of murine and human Langerhans cells with solid phase immunoabsorption using pan-leukocyte monoclonal antibodies.

Using a solid phase immunoabsorption (panning) technique, we have employed pan-leukocyte monoclonal antibodies to enrich and deplete murine and human Langerhans cells from cell suspensions of normal skin. Langerhans cell-enriched fractions contained 80-99% mononuclear cells, almost all of which had the ultrastructural features of Langerhans cells. These results are comparable to those achieved by panning for human Langerhans cells with anti-Leu-6(T6) antibody. Similarly, less than 1% of these cells were detectable in Langerhans cell-depleted fractions and such fractions were incapable of stimulating allogeneic lymphocytes in the skin cell-lymphocyte reaction. We conclude that panning with pan-leukocyte antibodies is an effective means of enriching or depleting Langerhans cells from heterogeneous skin cell suspensions and can yield results similar to those achieved with more Langerhans cell-specific reagents such as anti-Leu-6(T6). These findings are of particular significance to the enrichment and depletion of murine Langerhans cells since they express no known correlate of the human Leu-6(T6) antigen.

Animals↗
PubMed1985

Cystic dysplasia of the testis: sonographic and pathologic findings.

Sonographic and laboratory findings are presented for a case of left-scrotum testicular cysts in a 30-year-old man. Previously reported cases of this rare congenital malformation have occurred in infants and young boys. The patient showed previous evidence of the cyst at age 13. Sonographic images correlated well with previously published gross and microscopic descriptions.

Adult↗
PubMed1984

Langerhans cells react with pan-leukocyte monoclonal antibody: ultrastructural documentation using a live cell suspension immunoperoxidase technique.

Langerhans cells are generally regarded as members of an Ia+ dendritic cell system capable of potent accessory cell function in immune responses. While it has been shown that murine Langerhans cells are bone marrow-derived, the ontogenic relationships among human Langerhans cells, other dendritic cells, macrophages, and leukocytes in general have yet to be fully clarified. Recently, several pan-leukocyte monoclonal antibodies have been produced which react with the human leukocyte common antigen. This antigen resembles the murine T200 antigen and is expressed by all leukocyte subtypes but not by nonhematopoietic cells. Using an immunoperoxidase technique for staining suspensions of live skin cells, we have documented Langerhans cell reactivity with pan-leukocyte monoclonal antibody L3B12 at the ultrastructural level. Reactivity with this highly sensitive and specific pan-leukocyte marker supports the concept of the human Langerhans cell as a specialized form of bone marrow-derived mononuclear leukocyte and defines an immunologic feature common to dendritic cells, macrophages, and leukocytes that is not shared by other cell types. This finding is discussed in the context of other recent data concerning the immunologic phenotype of Langerhans cells. Since the immunoultrastructural method employed does not require cell fixation of any kind prior to immunologic staining, it should prove particularly useful for studying cell surface antigens that are adversely affected by fixation.

Animals↗
PubMed1984

Conjugated estrogens in the treatment of postmenopausal women with hyperparathyroidism.

Fourteen postmenopausal women with mild hyperparathyroidism were given conjugated estrogens. Serum calcium levels became normal and urinary calcium excretion was reduced for up to 2 years in ten patients taking an average dose of 1.25 mg of estrogen daily. Hypercalcemia returned quickly when therapy was interrupted. Estrogen did not systematically alter serum immunoreactive parathyroid hormone or calcitriol levels or urinary excretion of cyclic adenosine monophosphate. Significant reductions in urinary hydroxyproline and serum alkaline phosphatase activity during estrogen therapy indicate that the major effect of therapy was to decrease bone turnover. Iliac crest biopsy specimens taken before estrogen therapy showed normal trabecular bone volume and excessive osteoid seams. Follow-up biopsy specimens were taken from six patients after 1 year on therapy. Bone volume remained stable, but hyperosteoidosis had improved in only one patient. Without understanding the long-term impact of untreated mild hyperparathyroidism on bone, the benefits of estrogen therapy on bone remain uncertain. However, therapy with conjugated estrogens provides sustained control of serum and urine calcium in most women with hyperparathyroidism and is a reasonable alternative in patients who are not surgical candidates.

Adult↗
PubMed1983

Age-related loss of trabecular bone in premenopausal women: a biopsy study.

We measured the trabecular bone volume (TBV) of 62 iliac crest biopsies taken from women admitted to lymphoma protocols at Stanford University between 1970-1981. All subjects were active, cycling premenopausal women, with bone marrows that were negative for tumor. Disease status was stage III or less in 90% of the subjects. Trabecular bone volume was negatively correlated with age, and the annual predicted loss of bone was 0.14-0.18% TBV, or 0.7% of the original bone volume. In addition, there was a substantial range of normal TBV at any given age, evident even during adolescence. This study demonstrates that TBV is lost from iliac crest throughout adult life. The large spread in TBV indicates further that factors operating during adolescence or even earlier may have an important impact on skeletal mass.

Adolescent↗
PubMed1981

Effect of implant location on compressibility and capsule formation around miniprostheses in rats, and experimental capsule contracture.

Our study of experimental contracture in rats confirms the existence in laboratory animals of a phenomenon very much like human capsule contracture. The ultrastructural features of capsules in rats are essentially identical to those for humans and rabbits. Macrophages with silicon-containing material were present. Star-shaped myofibroblasts with extended processes appeared in contracted and noncontracted capsules. The myofibroblasts contained bundles of 60 to 80 A microfilaments with included dense bodies, convoluted nuclei, and extensive peripheral vesiculation. The myofibroblasts tended to be associated with more extensive ground substance and smaller diameter extracellular fibrils than were normal synthetic fibroblasts. The incidence of contracture was similar for implants beneath different amounts of overlying soft tissue dorsally and sternally, while compressibility and subjective softness were greater for implants beneath lesser amounts of overlying tissue. A greater mass of capsule formed beneath the heavier covering, however, suggesting that in clinical experience, cosmetically more acceptable results from submuscular prosthesis placement are probably due to a padding effect. Capsule glycosaminoglycans were primarily hyaluronic acid and dermatan sulfate. The occurrence of myofibroblasts in these capsules at a relatively late period (26 weeks) implicates myofibroblasts in the contracture mechanism, but details are still unknown. Contracture is a property of the capsule tissue; preliminary observations suggest that its occurrence is independent of species, anatomical site, surgical procedure, presence of extruded gel, presence of myofibroblasts, capsule thickness, or protein, collagen, or glycosaminoglycan composition. Cells within the capsule were geometrically asymmetrical, being extremely flattened in the plane parallel to the prosthesis surface.

Animals↗
PubMed1980

Mechanism of cis-platinum nephrotoxicity: II. Morphologic observations.

Light microscopy, transmission electron microscopy and scanning electron microscopy were used to characterize the morphologic alterations and to localize the site of injury within the kidney 1, 2, 3, 5 and 7 days after the intraperitoneal injection of cis-diamminedichloroplatinum. Pathologic alterations were evident 3 days after the injection of the drug and were localized to the S3 segment of the proximal tubule situated in the outer stripe of the outer medulla. A spectrum of changes was seen in this S3 segment which included a thinning or focal loss of brush border, cellular swelling, condensation of the nuclear chromatin and focal areas of necrosis. After 5 days, widespread tubular necrosis of the S3 segment in the outer stripe was the predominant finding. Necrotic tubular epithelial cells could be seen detaching from the basal lamina and being sloughed into the tubular lumen. Only a bare basal lamina remained in many areas. Regeneration of the S3 segment was seen after 7 days and was characterized by tubules with widely dilated lumens which were lined by many low-lying epithelial cells. The observation that cis-diamminedichloroplatinum exerts its nephrotoxic effect on the S3 segment of the proximal tubule located in the outer stripe of the outer medulla demonstrates that the pattern of injury produced by this antitumor drug is similar to that associated with other nephrotoxic and ischemic models of acute renal failure.

Animals↗
PubMed1978

Study of encapsulation of silicone rubber implants in animals. A foreign-body reaction.

It has long been known that the formation of a fibrous capsule around an implant is a general phenomenon in nature, an inevitable result of the tissue defense mechanism called the foreign body reaction. We have investigated this reaction in animals and find it consists of a series of interrelated processes in which the final result may vary, depending on the susceptibility of the foreign material to phagocytosis, incorporation by giant cells, or isolation by fibrosis. This susceptibility depends, in turn, on the physical and chemical properties of the implant. The process of capsule formation, as well as the structure of the final capsule, is similar in animal models and in humans--so that investigations of human encapsulation may be done in animals. The cause of abnormal induration around human breast implants is still unknown, and the question of whether normal induration in the animal model can be used to elucidate abnormal clinical induration depends on further investigation of both phenomena.

Animals↗
PubMed1978

Effects of local instillation of triamcinolone on the capsules around silicone bag-gel prostheses in animals.

"Soft" silicone bag-gel miniprostheses were implanted in 103 rats. The experimental animals had periprosthetic instillations of zero, 0.2, or 2 mg of triamcinolone acetonide at implantation. The compressibility, the architecture, and the chemical composition of the surrounding tissues were observed at 10 and at 120 days. The compressibility was also measured by mechanical means at 10 day intervals. At 120 days all capsules were similar. All the capsules gradually became firmer with time after the implantation. After 60 days, the steroid-treated capsules were very slightly more compressible (softer) than the controls. This slight difference in compressibility could not be correlated with the other changes in the capsule properties we examined. It is suggested that the structure of these capsules may be similar to that of immature scar, and that it is kept in this condition by the continued stimulus of the foreign implant.

Animals↗
PubMed1978

Cardiac trauma from angiographic injections. A quantitative study.

To relate angiographic injections to potential cardiac trauma, we verified a mathematic theory that allows quantitative definition of the kinetic energy content of contrast jets emanating from the exit holes of angiographic catheters. Cineangiographic recordings of a range of jets of known energy content were obtained in 18 cardiac canine experiments and energy content and dissipation were quantified precisely from center line to jet edge. All contrast jets produced in clinical angiographic practice were turbulent, even those from hand injections into the coronary arteries. Energy content was related to an estimated cardiac wall damage threshold. At energy levels and damage thresholds predicted by the theory and computations, a traumatic spectrum was found by cineradiology and microscopic examination. A unique curve independent of jet Reynolds number was discovered relating the penetration of the contrast jet into the intravascular blood to the potential for cardiac trauma. This curve allowed ready calculation of hydraulic energy dissipation for any clinically used angiographic catheter and the definition of safe operational injection flow rates. Thus potential cardiac trauma can be anticipated and prevented.

Angiography↗
PubMed1977

Peliosis hepatis. Twelve cases associated with oral androgen therapy.

Peliosis hepatis was encountered in 12 patients treated with high-dose oxymetholone or fluoxymesterone therapy. In three cases liver failure was the primary cause of death. In one case, the diagnosis was established by biopsy, the androgen therapy was discontinued, and the lesion was absent at autopsy two years later. In eight cases peliosis hepatis was an incidental finding at postmortem examination. The clinical and anatomic features of these cases are described, and previously reported cases of peliosis are briefly reviewed. A hypothesis is offered to explain the association of this peculiar lesion with anabolic androgen therapy.

Adult↗
PubMed1976

Duodenal immunoglobulin deficiency in graft versus host disease (GVHD) mice.

The small intestine is a well documented target organ in mouse and human GVHD, and diarrhea is a prominent part of the clinical GVHD syndrome. Although a plethora of systemic immune deficits has been documented in GVHD, the integrity of the small intestinal immune system has not been investigated. A correlation has not been demonstrated between systemic immune dysfuction and the incidence of lymphomas in mouse GVHD survivors. If gastrointestinal immune deficiency exists in mouse GVHD, its possible relationship to GVHD lymphomas, frequently abdominal. should be investigated. GVHD was produced in newborn BLA (C57 BL/Ka females x BALB-C males) mice house in a specific pathogen-free environment by the i.p. inoculation of 10(7) male BALB-C spleen cells. Control mice received syngeneic spleen cells. Twenty GVHD and 16 control mice were sacrificed at 3 weeks and specimens of duodenum were removed for routine histologic and immunofluorescent examination. All but one GVHD mouse (95%) had virtually absent duodenal IgA and IgM. Duodenal cellular fluorescence was demonstrated in all controls. A significant duodenal immunoglobulin deficit has been demonstrated in 3-week-old GVHD mice. The relationship of this finding to GVHD diarrhea, wasting, and neoplasia remains to be determined.

Animals↗