Biomedical subjects
J Becker
Publications and source records attributed to J Becker.
Suppression of phagocytosis by dexamethasone in macrophage cultures: inability of arachidonic acid, indomethacin, and nordihydroguaiaretic acid to reverse the inhibitory response mediated by a steroid-inducible factor.
Glucocorticoid steroids inhibit phagocytosis and cell spreading in cultures of murine resident peritoneal macrophages. It is postulated that these suppressive responses are mediated by a steroid-induced substance elaborated from dexamethasone-treated macrophages. Accordingly, dialyzed medium from dexamethasone-treated cultures was analyzed for the presence of a factor that inhibits phagocytosis and cell spreading in macrophage cultures not exposed to the steroid. When previously untreated macrophages were supplied dialysates from steroid-treated cultures, cell spreading and the phagocytic capacity (i.e. percentages of phagocytes in macrophage populations and the ability of phagocytes to ingest heat-killed Saccharomyces cerevisiae particles) decreased dramatically between 2 and 24 h after exposure. A lesser transient inhibitory response was observed when dialysates from untreated cultures were used. Relative to these controls after 48 h, phagocytic capacity and cell spreading remained suppressed in cultures treated with dialysates from dexamethasone-treated cultures. The addition of arachidonate, in the absence and presence of cyclooxygenase and lipoxygenase inhibitors, did not affect the phagocytic capacity of control macrophages. Furthermore, the addition of these compounds, either alone or in combination, to dexamethasone-treated cultures did not modulate the steroid-induced suppression of phagocytosis. These results support the hypothesis that the inhibition of phagocytosis and cell spreading may be mediated by a dexamethasone-induced non-dialyzable factor. In addition, the inability of arachidonic acid and inhibitors of prostaglandin and leukotriene biosynthesis to reverse the steroid-induced suppression of phagocytosis implies that the inhibition of this important macrophage function is not associated with the failure of dexamethasone-treated macrophages to release these mediators.
Linear growth following surgery in children and adolescents with Crohn's disease: relationship to pubertal status.
Studies of the effect of surgery on growth failure in adolescents with Crohn's disease have revealed conflicting data. To better determine the role of surgery for growth delay, growth data from 26 patients with Crohn's disease with intestinal resections and/or ileostomies were reviewed, 3 of whom had surgery twice. Operations were performed on 14 Tanner Stage I, 1 Tanner II, 1 Tanner III, and 13 Tanner IV or V patients. In the prepubertal group, 13 of the 14 had growth impairment, only one of whom had surgery primarily for that growth failure. One year after operation, 11 of 13 Tanner I growth failure patients experienced an increase in height velocity of 5.38 +/- 1.18 cm/yr (mean +/- SE;P less than 0.01); 9/11 achieved normal height velocity for Tanner I. Two attained their preillness height percentiles at one year follow-up, while 5 patients attained their preillness height percentiles 2.5 to 10 years following surgery. Of the four who failed to achieve normal height velocity, 3 had early recurrence of active disease. The Tanner Stage II and III patients both had growth failure, and both had a growth spurt following surgery. Of those who were Tanner Stage IV or V at the time of surgery, 5 of 13 had growth failure. Following surgery, none had an increase in height velocity. These data suggest that when patients with Crohn's disease and growth failure are prepubertal and surgery is performed primarily because of failure of medical therapy and/or other complications, a postoperative growth spurt may be expected within one year.
Loss of control, self-blame, and depression: an investigation of spouse caregivers of Alzheimer's disease patients.
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Analysis of oral papillomas, leukoplakias, and invasive carcinomas for human papillomavirus type related DNA.
Five papillomas, five leukoplakias, and six carcinomas were investigated for the presence of papillomavirus group-specific antigens and viral DNA. Viral proteins were identified with genus-specific papillomavirus antibodies. Cloned human papillomavirus (HPV) 11 and 16 DNA were used as probes in Southern blot hybridization at conditions of different stringency in order to determine viral DNA. Four of five papillomas, four of five leukoplakias, and three of six carcinomas reacted with HPV DNA probes and revealed some stained cells after exposure to HPV antibodies. HPV type 16 was found in one carcinoma and HPV type 11 was demonstrated in another case of carcinoma.
Streptococcus mutans and caries prevalence in rural Thai.
The prevalence of dental caries was studied in 521 rural Thai using the DMFT index. The oral habit of chewing betel nut was recorded. Samples of drinking water were examined for fluoride concentrations. Plaque material from 500 patients was examined qualitatively for S. mutans. The DMFT (dmft) index score was comparably high for patients under 10 yr of age (4.12); the difference between the DMFT (dmft) score of this age group and the other age groups was statistically significant. The average DMFT (dmft) score was 1.34 +/- 2.67. There was no relation between oral habits and caries prevalence. Fluoride concentrations of the water samples were between 0.11 and 1.64 ppmF- X 14.2% of 500 plaque samples were positive for S. mutans, predominantly of biotype I. The higher prevalence of caries in children may be attributable to changing patterns of life and nutrition.
The black layer on the teeth of betel chewers: a light microscopic, microradiographic and electronmicroscopic study.
Ten teeth of betel chewing P'wo Karen, a hilltribe group of northern Thailand, were available for this morphologic study. The structural composition of the black layer on these teeth was studied by light microscopy, microradiography and by electronmicroscopy. Principally, the black layer on the teeth of betel chewers was identical with subgingival calculus which had been colored by specific polyphenols contained in the betel nut. However, a pellicle-like layer forming initially on enamel crystals was also observed. From the morphologic aspect of the black layer a specific anticariogenic property cannot be attested. Further studies on the chemical composition of this black layer may elucidate its probable anticariogenic and its carcinogenic properties relative to oral submucous fibrosis.
[Immunohistologic studies of chronic apical periodontitis and radicular cysts].
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[Acute respiratory distress syndrome in the adult. Distribution of the ventilation-perfusion ratio].
Hypoxemia in the acute respiratory distress syndrome may be due to a variety of causes: trùe pulmonary shunt, decreased ventilation/perfusion ratios, impaired diffusion and/or fall of mixed venous oxygen. In order to sort out these different tension mechanisms, 18 patients with acute respiratory distress syndrome were explored by the inert gas method. In 6 of them hypoxemia was due to a true shunt (35 +/- 10%). The remaining 12 patients also had a true shunt (26.5 +/- 9.5%), but 4.5% of the cardiac output was distributed to areas with a ventilation/perfusion ratio between 0.1 and 0.005. Thus, in these 18 patients with acute respiratory distress, hypoxemia could be explained essentially by a true shunt.
Adoptive autoimmunotherapy. Cytotoxic effect of an autologous long-term T-cell line on malignant melanoma.
The in vitro and in vivo cytotoxic effects of an autologous long-term T-cell (LTTC) line were evaluated in a 65-year-old man with metastatic malignant melanoma. The patient's own T-cells were grown from a peripheral blood sample in a lymphocyte-conditioned medium. The cytotoxic effect of the LTTC against the patient's cultured melanoma cells was determined in vitro using the method of 51Cr release. Long-term T-cells produced specific lysis of 34% at an effector:target ratio of 30:1. Using allogeneic melanoma target cells, comparable or greater lysis was obtained in vitro. Long-term T-cells were injected into the infratumor and peritumor regions of two subcutaneous melanoma metastases of a lower extremity. A second injection of one of these lesions was followed 3 days later by an excisional tumor biopsy. Histologic examination showed many lymphocytes and necrotic areas in the injected lesions. Electron microscopic examination revealed numerous areas of lymphocyte-melanocyte membrane contact, membrane thickening, disintegration, hydropic cytoplasmic changes, and irreversible nuclear degenerative changes of melanocytes. Dividing lymphoblasts were also seen. These changes did not occur in noninjected tumor nodules. Long-term T-cell cultures yield immunologically functional cells capable of cytotoxic activity against allogeneic and autochthonous melanoma in vitro and against autochthonous melanoma in vivo. In vivo use after in vitro expansion of autologous immunocompetent cells (adoptive autoimmunotherapy) appears to be a feasible new approach to the study of human tumor immunology and treatment.
Coexpression of keratin and vimentin filaments in adenoid cystic carcinomas of salivary glands.
Six cases of adenoid cystic carcinoma of salivary glands have been examined with antibodies specific for either keratin or vimentin. Tumor cells in all six cases showed coexpression of keratin and vimentin.
Nucleotide sequence of the gene, protein purification and characterization of the pSC101-encoded tetracycline resistance-gene-repressor.
The nucleotide sequence of the pSC101-encoded tetracycline repressor gene (tetR) was confirmed. The deduced amino acid sequence is compared to that of other repressor proteins. To overproduce the repressor protein, tetR was placed under the control of bacteriophage lambda promoter pL. Tet repressor protein was purified to homogeneity and shown to bind specifically to two tet operators and also to tetracycline (Tc). The inducer function of Tc is demonstrated by the loss of the specific binding between the tet operator DNA and the Tet repressor-Tc complex.
Increased arterial carbon dioxide tension due to enteral nutrition during mechanical ventilation.
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Occurrence of papillomavirus structural antigens in oral papillomas and leukoplakias.
Six oral papillomas and 7 oral leukoplakias were studied with genus-specific antibodies against detergent-disrupted papillomaviruses. Indirect immunofluorescence staining was applied to frozen sections. Distinct nuclear staining of superficial keratinocytes was seen in 5 of 6 oral papillomas, 2 of 5 homogenous leukoplakias, and in 2 cases of nodular leukoplakia, one of these showing transition into an invasive carcinoma. Papillomavirus antibodies offer a new way to detect and localize papillomaviruses in epithelial hyperplasias. The relevance of the immunomorphological identification of papillomavirus-associated antigens is discussed with special reference to the molecular hybridization technique.
Morphologic study of jejunal mucosal transplants for the replacement of oral mucosa.
Biopsies were taken at 8 and 12 weeks and at 6 months from oral jejunal mucosal transplants in 5 patients who had undergone extensive surgery for tumors of the floor of the mouth. Microvascular anastomosed jejunal mucosa had been used for the primary reconstruction. Histological findings included flattening of the jejunal relief, atrophy and erosion of the epithelium with reduction of jejunal excretion and marginal overlapping of oral mucosa. Immunohistochemical labelling of the cytoskeleton revealed that jejunal epithelium does not undergo rapid metaplasia in the course of adaptation to oral mucosa. These findings indicate that the jejunal mucosa does not completely change its architecture and does not adapt to the requirements of the oral cavity after a period of 6 months.
Design principles of the Stratus fluorometric immunoassay instrument.
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[Liver biopsy in surgery of the gallbladder].
Biopsy of the liver with the menghini needle was done as a routine diagnostic procedure during surgery in 581 cases. During earlier decades morphological changes of the liver could be demonstrated by that procedure in 80-100% of the patients. In contrast such changes could be found only in 55% of our cases; in 5,5% these changes were severe. From these numbers it should be concluded that liver biopsy during gall bladder surgery is not necessary as a routine procedure. If patients are selected for biopsy on the basis of history, ultrasonography, laboratory data and intraoperative microscopical liver findings this procedure is necessary only in 14% of the cases, complication rate being 0,09%. In this particularly selected group changes of the liver can be found in 90,4%, severe changes in 33% of the cases. Pathological changes of the liver are likely to occur in 65-91% of patients with complicated gall stone disease and/or accompanying diseases like diabetes, obesitas, alcoholism, or a history of hepatitis. In this particular group biopsy and histological examination during surgery seem to be indicated as it was the case before.
[Correlation between the measurement of PO2 by percutaneous route and the measurement of cutaneous irrigation by thermal clearance in the foot in chronic obliterative arteriopathies of the lower limbs].
Possible influence of skin circulation in percutaneous determination of pedal TcPO2 of patients with lower limbs arteriopathy was investigated. Findings demonstrated close correlation between TcPO2 and the morphology of the pulsatile signal on digital plethysmography in hyperemia, and the degree of lower limbs ischemia, particularly during the stage of permanent ischemia. Histograms of skin irrigation values measured by thermal clearance were similar in normal subjects and patients with lower limbs arteriopathy. Values for skin irrigation measured in this way failed to show linear correlations with TcPO2 values. These findings suggest that TcPO2 values reflect any global tissue ischemia at the measurement site and not cutaneous vascularization alone.