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Biomedical subjects

S Lang

Publications and source records attributed to S Lang.

At least 253 records · Page 14Linked to original sources
PubMed1992

Changes in lymphocyte subsets and mitogen responsiveness following open-heart surgery and possible therapeutic approaches.

Septic multi-organ failure represents a common cause for operative mortality following open-heart surgery. One major reason might be the depression of cell-mediated immunity. The purpose of this prospective randomized trial was to quantify and specify the effects of open-heart surgery on cell-mediated immune mechanisms. In addition, the immunorestorative potential of a combined immunomodulatory therapy with the cyclooxygenase inhibitor indomethacin and the thymomimetic substance Thymopentin versus single drug administration of indomethacin was investigated. Twenty patients were given indomethacin for the first 5 postoperative days (group A). Another 20 patients also received Thymopentin perioperatively and on the second and fourth postoperative days (group B), while 20 patients underwent conventional therapy (group C). Cell-mediated immune response was quantified in vitro by measuring CD3+ T-lymphocytes and their subsets, CD4+ T-helper and CD8+ T-suppressor cells. Lymphocyte responsiveness to a specific (Antigen-Cocktail) and non-specific mitogen (phytohemagglutinin) provided information about the quality of cell-mediated immune response. On the first postoperative day CD3+ T-lymphocyte counts and Antigen-Cocktail-induced lymphocyte proliferation decreased significantly in all groups. The number of CD4+ T-Helper cells fell significantly only in groups A and C, while the decrease in group B was not statistically significant; the same applied to phytohemagglutinin-induced lymphocyte response. The CD4+/CD8+ ratio was significantly depressed only in group C, decreased slightly in group A and did not change as compared to baseline values in group B. All investigated parameters remained significantly depressed until the seventh postoperative day in group C.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Comparison of the effects of moist and dry conditions on the process of angiogenesis during dermal repair.

The effect of moist and dry conditions on the process of angiogenesis during dermal repair was investigated. The moist conditions were achieved by covering excised wounds on porcine flank skin with the adhesive polyurethane dressing Opsite and dry conditions were achieved by exposure to air through dry gauze dressings. Angiogenesis was assessed during the period from 3 to 60 d after injury. Quantitative studies, using computerized image analysis, were carried out on microfocal x-ray images of skin sections whose blood system had been perfused in vivo with a radio-opaque medium. The analytical technique yielded information with regard to vessel number per wound and also the area occupied by blood vessels per unit wound area. Three regions were assessed in each wound bed: upper zone, just below the surface of the wound; the lower zone, just above the base of the wound bed; and the middle zone, midway between the other two zones. The results showed that the wounds maintained in a moist environment revascularized at a greater rate than those maintained in a dry environment. This was apparent in all of the zones of the wound bed examined. The development of new vessels occurred in a more orderly manner in the moist wounds. There was an early increase in vessel number rising to a peak around days 3-5, then a gradual decrease in number starting around day 7. In contrast, in the dry wounds the development of blood vessels was less rapid. Peak vessel number in the upper zone was significantly less than that achieved in the moist wounds, and was not reached until 7 d after injury. The decrease in vessel number from the peak was less rapid in the dry wounds, suggesting that there was a delayed entry into the remodeling phase in comparison with the moist wounds. The results also showed that the total percentage area of the wound bed occupied by blood vessels was greater in the moist wounds than the dry wounds from 3 d after injury until day 7. This level of vascularization was maintained beyond 7 d after injury even when the vessel number in the moist wounds was significantly less than in the dry wounds, suggesting that the vessels in the moist wounds were larger and, presumably, more mature. In general, moist wounds showed a more rapid decline towards uninjured skin levels of vascularization than dry wounds.

Animals↗
PubMed1992

Age-associated changes of the triangular fibrocartilage of the wrist: evaluation of the diagnostic performance of MR imaging.

To define the appearance of degenerative changes of the triangular fibrocartilage (TFC) of the wrist on magnetic resonance (MR) images, the TFCs in one wrist of each of 30 healthy subjects in three age groups (20-35, 36-50, and greater than 50 years) and six TFCs from fresh cadavers were examined by means of coronal T1-weighted spin-echo sequences. Histologic findings were compared with findings on MR images in the cadaveric TFCs. It was proved that patches or lines of signal hyperintensity within the cadaveric TFCs were caused by degenerative changes and tears. Similar changes of the TFCs on MR images of the healthy subjects may have been caused by degeneration. In the healthy subjects, degenerative changes of the TFC, usually well defined on MR images, occurred at a very early age. The TFC appears to undergo stages of degeneration comparable to those of the menisci of the knee, but differentiation between traumatic and degenerative tears may be difficult.

Adult↗
PubMed1992

Statement: occupational therapy services in work practice.

Occupational therapy practitioners focus on the individual's ability to participate in productive occupations throughout their life span. Through prevention, assessment, and intervention strategies, occupational therapy practitioners often collaborate with other members of the health care team and assist persons to optimize their ability to engage in purposeful occupation while facilitating a safe and successful entry into or return to work.

Accidents, Occupational↗
PubMed1992

Survival analysis of octogenarian patients with coronary artery disease managed by elective coronary artery bypass surgery versus conventional medical treatment.

BACKGROUND: In view of the increasing age of the U.S. population, the use of coronary artery bypass surgery in the management of the elderly patients with coronary artery disease needs to be better defined. METHODS AND RESULTS: To evaluate the effects of medical and surgical therapy on octogenarian patients with coronary artery disease in our institution, we retrospectively reviewed 177 consecutive octogenarians who underwent cardiac catheterization over a 5-year period. Sixty-five of these patients were found to have significant coronary artery disease without severe valvular disease. Elective coronary artery bypass surgery was performed in 36 patients, whereas 29 patients were continued on maximization of medical therapy and not referred to the surgical service. Left ventricular ejection fractions (LVEF) were similar for the two groups, whereas the surgical patients had slightly higher average number of diseased coronary vessels and slightly higher levels of angina. Univariate survival analysis of 20 variables, including the choice of medical versus surgical treatment and the associated conditions, was performed by Mantel-Cox testing of the paired Kaplan-Meier product limit survival curves stratified by the subgroups of each variable. The variables found to be significant were then included in a multivariate survival analysis using the Cox proportional hazards regression model. The treatment choice, LVEF, level of angina, and presence of any aortic and/or mitral valvular disease at the time of cardiac catheterization were found to be independent prognostic indicators of survival in the follow-up period of 26 +/- 16 months. The 3-year probability of survival rates for the surgical patients and medical patients were 77.4% and 55.2%, respectively (p = 0.0294). The New York Heart Association functional class of the surgical group decreased significantly from a mean preoperative level of 3.4 +/- 0.5 to a mean level of 1.2 +/- 0.6 at the follow-up interview (p < 0.01), whereas it did not significantly change for the medical group from a baseline mean level of 2.8 +/- 1.3 to a mean follow-up level of 2.5 +/- 1.0. CONCLUSIONS: We conclude that coronary artery bypass surgery provided improved long-term survival and functional benefit compared with conventional medical treatment in a small group of octogenarian patients in our institution.

Aged↗
PubMed1991

Congenital malignant melanoma of the eye.

Twenty-three cases of congenital malignant melanoma have previously been reported. Here the authors report the first case of a congenital malignant melanoma arising in the eye. A newborn girl had a large pigmented ocular tumor, hepatomegaly, and multiple pigmented skin and choroidal lesions. The histopathologic diagnosis was of a malignant melanoma with hepatic metastases. The skin and choroidal lesions were considered to be congenital melanocytic nevi. The most plausible pathogenetic link between these two conditions was that the malignancy had arisen as a second-hit mutation within a choroidal congenital melanocytic nevus. Despite widespread metastases the baby, treated by surgery and chemotherapy, survives in good health, aged 2 years, 10 months.

Eye Neoplasms↗
PubMed1991

Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex.

Three case reports are presented to illustrate the existence and importance of reflex bradycardic responses that can occur during maxillofacial surgical procedures. All three patients were healthy young adults undergoing operations which did not include any manipulation of orbital structures. After the patients had been anaesthetized for some time and were haemodynamically stable, profound bradycardia or ventricular asystole occurred suddenly in response to manipulations of the bony structures of the maxilla or mandible, or dissection of, or traction on, the attached soft tissue structures. The parasympathetic supply to the face is carried in the trigeminal nerve. Alternative afferent pathways must exist via the maxillary and/or mandibular divisions, in addition to the commonly reported pathway via the ophthalmic division of the trigeminal nerve in the classic oculocardiac reflex. The efferent arc involves the vagus, regardless of which branch of the trigeminal nerve transmits the afferent impulses. All patients undergoing maxillofacial procedures should be monitored carefully for reflex bradycardia and ventricular asystole.

Adult↗
PubMed1991

Tumours of mesothelial origin in rats following inoculation with biogenic silica fibres.

Pleural implant experiments using Sprague-Dawley rats have shown that those injected with the carcinogen 15,16-dihydro-11-methylcyclopenta[a]phenenthren-17-one (11-methyl-17-ketone) intraperitoneally followed by silica fibres intrapleurally develop mesotheliomas. These tumours were histologically similar to those induced by crocidolite alone. The intraperitoneal injection of 11-methyl-17-ketone also induced leukaemia.

Adenoma↗
PubMed1991

Immunomodulatory therapy with thymopentin and indomethacin. Successful restoration of interleukin-2 synthesis in patients undergoing major surgery.

Prostaglandin E2 (PGE2)-mediated monocyte (M phi) suppressor activity and inadequate T-helper cell function represent the mechanistic keystones of trauma-induced impairment of cell-mediated immunity (CMI). In a prospective randomized trial, the immunorestorative potential of a combined therapy with the thymomimetic substance Thymopentin (TP-5; Timunox, Cilag GMBH, Sulzbach, FRG) and the cyclooxygenase inhibitor indomethacin (Indo) in 60 patients (mean age, 63 +/- 2 years) undergoing open heart surgery was studied. Perioperative immunologic screening was carried out on days -2, 3, 1, 5, and 7 and included the in vivo delayed type hypersensitivity (DTH) skin response, phenotyping for peripheral blood mononuclear cell (PBMC)-specific and nonspecific induction of lymphoproliferative responses, in vitro interleukin-2 (IL-2) synthesis, as well as the serum concentration of D-erythro-Neopterin (NPT) and of gamma interferon (gamma-IFN). The study protocol comprised three groups (n = 20): PA (Indo 150 mg administered intravenously on days 0 to 5), PB (TP-5 administered subcutaneously on days 0, 2, 4, and Indo), and PC (control). In contrast to PC, significant immunorestoration could be demonstrated in PB, as DTH scores on day 7, as well as proliferative responses in cell cultures were not depressed after operation (p less than 0.05). Cell-surface receptor expression for the CD3+, CD4+, and IL-2 receptor-positive (IL-2R+) lymphocyte subpopulations following surgery was reduced to 75% of baseline values in PC, while in PB, receptor protection for CD4+ and IL-2R+ subpopulations (more than 15% above baseline) was observed. Interleukin-2 synthesis (average baseline value, 0.7 + 0.08 U/mL) in cell cultures of PC was massively suppressed, with lymphokine concentrations in the supernatants never more than 0.27 +/- 0.05 U/mL. In PA cultures, IL-2 synthesis was impaired as well but not as precipitously as in PC. In contrast, in PB cultures, the average IL-2 production on consecutive postoperative days was never below baseline values. This study clearly demonstrates that the combined Indo/TP-5 therapy is superior to single Indo administration and can adequately preserve and/or restore intact M phi T-cell interaction and thus appears to be a feasible approach to maintain normal host defense activity in traumatized individuals.

Adjuvants, Immunologic↗
PubMed1991

Comparison of the effects of semi-occlusive polyurethane dressings and hydrocolloid dressings on dermal repair: 1. Cellular changes.

The effects on dermal repair of two wound dressings, one the semi-occlusive polyurethane sheet Opsite, the other the hydrocolloid Granuflex, were compared in full-thickness excised lesions on porcine skin during the period from 5 d to 6 months after injury. Quantitative studies were made of changes in the populations of polymorphonuclear leucocytes, macrophages, fibroblasts, and endothelial cells. The progress of repair in the wounds covered with the semi-occlusive dressing showed a decrease in the number of inflammatory cells (polymorphonuclear leukocytes and macrophages) from 5 to 60 d, whereas the number of proliferative phase cells (fibroblasts and endothelial cells) increased from 5 to 7 d. The total cellularity per unit area showed an increase between 5 and 7 d, that is, during the proliferative phase of repair, and then progressively decreased as the proliferative phase was succeeded by the remodeling phase. In contrast, the repair process in the hydrocolloid-dressed wounds was more complex. The number of inflammatory cells remained relatively high throughout and there were consistently fewer endothelial cells present throughout. Fibroblast number showed an initial fall from 5 to 14 d but then started to increase in number from 21 to 60 d. This chronic inflammatory reaction appeared to be in response to particulate matter that had been incorporated into the wound bed and hypodermis, and was still apparent 6 months after injury, when hydrocolloid particles were detectable microscopically in the hypodermis.

Animals↗
PubMed1991

Giant thymic carcinoid.

Thymic carcinoid is a rare tumour. It may present with ectopic endocrine secretion or with symptoms of compression as a result of its size. A case is reported which presented with symptoms of compression where the size of the tumour was uniquely large such as to warrant the term giant thymic carcinoid. The typical histological features are described, together with its possible origin and its likely prognosis.

Carcinoid Tumor↗
PubMed1991

Formation and spontaneous closure of an arteriovenous fistula after transvenous pacemaker placement.

We report the findings in a patient with the unusual complication of arteriovenous fistula formation of the subclavian vessels seven weeks following placement of a dual-chamber pacemaker. The fistula's subsequent course was equally unusual, closing spontaneously three weeks later. It is postulated that the thrombotic and fibrotic reaction elicited by the leads contributed to the fistula's closure. Two surgical procedures, correction of the fistula and reimplantation of the pacemaker, were thus avoided by careful monitoring of the patient.

Aged↗
PubMed1991

Devitalizing effects of phenol on bone marrow cells. Histologic study on cadaveric animal vertebrae.

The devitalizing effects of 5-90 percent phenol for 30 seconds on bone marrow cells were examined on vertebral bodies of fresh animal cadavers. Evaluation was made by measuring the width of the zone of necrotic cells. The zone increased with rising phenol concentration up to 75 percent, reaching an average width of 0.75 mm. However, when protected by bone trabeculae, the cells escaped devitalization.

Animals↗
PubMed1991

The investigation of antiepileptic action of qingyangshen (QYS)--effect of QYS on the concentrations of neuropeptides in rat brain.

The concentrations of central neuropeptides, somatostatin (SS) and substance-P (SP), were determined in the different brain regions of young-aged male rats after a long-term administration of anticonvulsants Qingyangshen (QYS), Diphenylhydantoin (DPH), and Carbamazepine (CBZ). The results were compared with Pentylenetetrazol (PTZ)-induced seizure model and normal saline-treated controls. No effects of QYS on the concentrations of SS and SP were found in the rats of four-week or eight-week group. Both of DPH and PTZ increased the SS levels in the midbrain of rats in four-week group. DPH, CBZ, and PTZ also increased the SP levels in the cerebral cortex, striatum, and brain stem of rats in eight-week group. Our present data indicated that the central neuropeptides SS and SP were involved in the processes of epilepsy and antiepilepsy. Since QYS did not influence the contents of SS and SP after a long-term administration, it suggested that the anticonvulsant mechanism of QYS may be different from those of DPH and CBZ, i.e. it may be not due to its effect on the central neuropeptide pathway.

Animals↗
PubMed1991

Behavior of neutron-activated uranium dioxide dust particles in the gastrointestinal tract of the rat.

The behavior of neutron-irradiated, simulated Chernobyl UO2 particles containing 141Ce, 144Ce, 95Zr, 95Nb, and 103Ru in the gastrointestinal tract was investigated to obtain basic information for dosimetric and risk analyses of nuclear accidents. After the UO2 particles were administered to rats intragastrically, the distribution and retention of specific radionuclides were studied by using whole-body autoradiography and gamma-spectrometric analysis of tissues. None of the radionuclides were detected in liver, kidney, muscle, bone, brain, blood, and urine. Approximately 98% of the total administered radioactivity was excreted in feces within 3 days. A two times greater intestinal retention (about 6%) of 95Nb than for the other radionuclides was observed 1 day after administration. The results indicate that this kind of relatively insoluble particulate material is not absorbed or retained significantly in the epithelial cells of the intestinal wall. Fallout particles containing high-energy beta sources, 106Ru and 144Ce, result in a very high radiation dose (up to several Gy/day) in the vicinity of a hot particle. Niobium-95 with low average beta energy (0.043 MeV (100%)) does not increase the total dose to the GI tract significantly despite its longer retention in the intestine. Evaluation of the biological effects of these particles in the GI tract by using a dosimetric model based on uniform distribution of activity may be misleading.

Animals↗
PubMed1990

Microbial glycolipid production under nitrogen limitation and resting cell conditions.

Rhodococcus erythropolis is able to synthesize an anionic trehalose-2,2',3,4-tetraester during cultivation on n-alkanes. Preconditions for an overproduction are nitrogen limitation, temperature- and pH-shift. The optimum carbon source was technical grade n-C-10, which led to 0.35 g g-1 of glycolipid per n-alkane. Electron microscopical observations showed that n-C-14,15 (technical grade) grown cells contained numerous lipid inclusions in contrast to n-C-10 (technical grade) grown cells. Nocardia corynebacteroides synthesizes a novel pentasaccharide lipid and as size products small amounts of trehalose-corynomycolates. Optimum precursors for overproduction are n-alkanes from n-tetradecane to n-hexadecane with yields in the range of 0.17 g g-1 of glycolipid per carbon source.

Biotechnology↗