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Biomedical subjects

T Lang

Publications and source records attributed to T Lang.

At least 217 records · Page 12Linked to original sources
PubMed1991

[Comparison of conventional radium and high dose rate afterloading brachytherapy in cervix cancer].

The combination of intracavitary and external-beam radiation is the treatment of choice in advanced cervical cancer. Low-dose regimens using radium were widely abandoned in favour of high-dose-rate afterloading systems. We compared in this retrospective analysis of 550 patients the 2 different treatment modalities. We could observe neither in overall survival, nor in the incidence of side effects, any significant difference. Although the change from low- to high-dose-rate radiation therapy was not accompanied by a benefit in survival, the latter modality displayed several advantages e.g. a reduced exposure of personnel to radiation and shorter duration of confinement to bed. Patient survival rate was dependent mainly on parameters of tumour burden (FIGO stage), i.v. pyelogram or CT scan of paraaortic lymph nodes. On the other hand, neither the histological classification as epidermoid or adenocarcinoma nor the WHO grading, were useful predictors of patient outcome.

Adenocarcinoma↗
PubMed1991

[Snowboarding injuries].

This retrospective study includes 59 people treated at our trauma centre for snowboard accidents that happened in the 1989 winter season. 22 People were severely injured. 2 people died due to a polytrauma. One fracture of the cervical vertebrate column was followed by complete hemiplegia. Reasons for these accidents were a lack of knowledge how to behave outside the marked alpine regions, as well as lack of technical equipment and theoretical education.

Adolescent↗
PubMed1991

Appropriateness of admission in an emergency department: reliability of assessment and causes of failure.

The validity of a modified version of the appropriateness evaluation protocol was assessed in a sample of patients aged 15 and over admitted by means of the emergency department of one of the Paris hospitals. As measured among 371 patients, the reliability of the indicator was high. The prevalence of inappropriate admissions (IA) was found to be 20% using the expert opinions and 25% the instrument. Homelessness was associated with a higher prevalence of IA (34%). Other social factors and age were not related to IA. According to the experts' opinions, difficulties in organizing the continuity of care for patients examined in the emergency room were one of the main causes for IA.

Adolescent↗
PubMed1991

Application of posterior plating and modifications in thoracolumbar spine injuries. Indication, techniques, and results.

Out of 281 patients with recent injuries to the thoracic and lumbar parts of the spine, 243 underwent posterior plating. Of these, 172 patients had an average follow-up of 3.2 years. The consecutive analysis of morphologic results led to modifications of the original Roy-Camille technique. In analogy to the system developed by Zielke for anterior derotation spondylodesis, plates were used in combination with VDS screws, threaded rods, and nuts, thus creating an implant with initial angle variability but final angle stability. The development of transpedicular reduction and cancellous bone grafting for the treatment of vertebral body fractures, later supplemented by transpedicular discectomy and intercorporal cancellous bone grafting, effected a significant improvement in the results of posterior plating. Although the use of traditional plating was followed by correction losses of 14 degrees, the loss could be reduced to less than 6 degrees by the new system, which nearly corresponds to the physiologic anatomy of the spine.

Adult↗
PubMed1991

Localization of major histocompatibility complex class II molecules in phagolysosomes of murine macrophages infected with Leishmania amazonensis.

Leishmania-infected macrophages are potential antigen-presenting cells for CD4+ T lymphocytes, which recognize parasite antigens bound to major histocompatibility complex class II molecules (Ia). However, the intracellular sites where Ia and antigens may interact are far from clear, since parasites grow within the modified lysosomal compartment of the host cell, whereas Ia molecules seem to be targeted to endosomes. To address this question, the expression and fate of Ia molecules were studied by immunocytochemistry in Leishmania amazonensis-infected murine macrophages stimulated with gamma interferon. In uninfected macrophages, Ia molecules were localized on the plasma membrane and in perinuclear vesicles, but they underwent a dramatic redistribution after infection, since most of the intracellular staining was then associated with the periphery of the parasitophorous vacuoles (p.v.) and quite often polarized towards amastigote-binding sites. The Ii invariant chain, which is transiently associated with Ia during their intracellular transport, although well expressed in infected macrophages, apparently did not reach the p.v. Similar findings were observed with macrophages from mice either resistant or highly susceptible to Leishmania infection. In order to determine the origin of p.v.-associated Ia, the fate of plasma membrane, endosomal, and lysosomal markers, detected with specific antibodies, was determined after infection. At 48 h after infection, p.v. was found to exhibit a membrane composition typical of mature lysosomes. Overall, these data suggest that (i) Ia located in p.v. originate from secondary lysosomes involved in the biogenesis of this compartment or circulate in several endocytic organelles, including lysosomes and (ii) p.v. could play a role in antigen processing and presentation. Alternatively, the presence of high amounts of Ia in p.v. could be due to a Leishmania-induced mechanism by means of which this organism may evade the immune response.

Animals↗
PubMed1991

[A new contribution of Doppler echography of renal arteries: follow-up studies of angioplasties. A retrospective study of 50 cases].

OBJECTIVE: analysis of Doppler Duplex (DD) contribution to renal artery percutaneous angioplasty (ATL) follow-up. METHOD: between 1983 and 1989, SO ATL were performed in 47 subjects with renovascular hypertension. Their average age was 50 +/- 12 years. The lesions were fibromuscular dysplasia (n = 20) and atherosclerosis (n = 27). The DD was performed simultaneously with arteriography (A degrees) (considered the gold standard), when the stenosis was discovered (n = 32), before (n = 32) and after (n = 39) ATL, and during the follow-up between the 6th and 12th month (n = 38). RESULTS: during the initial exploration, the concordance between DD and A degrees is 78% and the sensitivity of DD for the diagnosis of stenosis is 90%. ATL was performed once on the basis of DD alone, that showed a tight and significant stenosis with dysplasia, when A degrees failed to detect it. ATL confirmed the lesion and was successful, and hypertension cured. The concordance DD-A degrees before and after ATL is respectively 88% and 77%. At the late control, the concordance is 92%, the sensitivity 73% and the specificity 85% for all stenosis. While maintaining a good specificity, DD recognized the 3 tight found by the A degrees control. The complications encountered during ATL were diagnosed by DD most of the time: all the local complications at the site of entry (n = 5), all the dissections with obliteration (n = 2) and 5 of the 8 dissections without obliteration of the renal artery. CONCLUSION: the detection and the lesional assessment of post-ATL complications are facilitated by DD. The good sensitivity of DD combined with satisfactory specificity will allow the reduction of angiographic surveillance by taking advantage of a non-invasive method.

Adult↗
PubMed1991

Localization of MHC class II molecules in murine bone marrow-derived macrophages.

The localization of MHC class II molecules (Ia) was studied by ultrastructural immunocytochemistry in murine bone marrow-derived macrophages stimulated by recombinant interferon-gamma (rIFN-gamma). Ia molecules were detected on the plasma membrane and on the limiting membrane and internal structures of vesicular acidic compartments. Some of these vesicules also contained cathepsin B and/or cathepsin D. The use of BSA-gold, a marker of fluid phase endocytosis, allowed the identification of Ia-positive organelles as endocytic compartments. The first to be labelled with BSA-gold also contained the cation-independent mannose 6-phosphate receptor (MPR) but not the 120,000 molecular weights lysosomal glycoprotein (lgp 120). Later on, BSA-gold appeared in Ia+, MPR+, lgp 120+ compartments. Collectively these data suggest that intracellular Ia molecules are mainly present in early and late endosomes.

Animals↗
PubMed1991

[Experimental studies of photodynamic therapy of squamous cell cancers with hematoporphyrin derivative].

The target tissue of photodynamic therapy (PDT) of tumours by haematoporphyrin derivative (HPD) in vivo is controversial. A direct attack on the malignant cell itself, an indirect effect via the vascular system supplying the tumour, or a combination of both factors, have been suggested. We investigated this question in squamous cell carcinoma in experimental animals. Histology showed massive interstitial bleeding in carcinomas induced in the mucosa of the cheek pouch of hamsters or in the skin of mice, indicating a vascular response to PDT. However, it was also possible to induce similar changes in the neighbourhood of newly formed vessels at the margin of an inflammatory reaction induced in the cheek pouch of the hamster in the absence of tumour cells. We implanted cells from human squamous cell carcinomas into athymic nude mice and found that carcinoma cells removed immediately after PDT remained viable, whereas tumour cells left in situ died. Thus, the point of action of PDT and HPD in vivo is not the tumour cell itself, but the vascular stroma of the tumour or its immediate vicinity.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1991

Transmission and scanning EM-immunogold labeling of Leishmania major lipophosphoglycan in the sandfly Phlebotomus papatasi.

Previous studies using immunostaining and light microscopy demonstrated expression of Leishmania major lipophosphoglycan (LPG) on parasites developing in the sandfly gut from 2 days post infection. By days 4 to 7 post infection, there appeared to be large amounts of parasite-free LPG deposited on/in the microvilli and epithelial cells lining the thoracic midgut, while forward migration of parasites and the morphological changes which accompany metacyclogenesis were associated with developmental modification of the LPG molecules. Studies presented here examine this process with much greater precision using electron microscopy and immunogold labeling techniques to study the different developmental forms (nectomonads, haptomonads, paramastigotes, and metacyclics) of promastigotes in the sandfly gut. Results obtained using LPG-specific monoclonal antibodies (WIC79.3, 45D3 and the metacyclic-specific 3F12) show (1) gold labeling over the cell surface, within the flagellar pocket, and extending along the entire length of the flagellum of electron-dense nectomonads observed in the abdominal and thoracic midgut regions on days 4 and 7 post infection, and of electron-lucid haptomonads in the foregut, (2) dense labeling around the flagellar tips, by which nectomonad forms bind to the midgut microvilli, but not on the microvilli themselves or within the epithelial cells lining the midgut, (3) significant metacyclic-specific (3F12) labeling on nectomonad forms in the lumen of the midgut and attached to the microvilli, and (4) dense labeling on the cell surface of electron-lucid paramastigotes in the esophagus and in the filamentous matrix surrounding paramastigote and metacyclic forms in the esophagus and pharynx. These results are discussed in the light of the proposed roles for LPG in parasite attachment to, and survival in, the sandfly gut.

Animals↗
PubMed1991

Antigen processing and presentation: modelling with Leishmania.

Most foreign antigens are "processed" by APC into a form in which they can bind MHC molecules and be recognised by the TCR. Functional and immuno-gold labelling studies have been used to determine the putative sites of MHC-Ag interaction following uptake of Leishmania donovani into a phagolysosome. During infection with this parasite in vivo, upregulation of class II occurs. Based on studies using scid mice, NK cells appear to contribute little to this process. During chronic infection, however, APC function is diminished in spite of high class II levels. We propose that a lack of coordinate costimulator expression may lead to subsequent loss of T cell function late in infection, by a mechanism involving the induction of T cell unresponsiveness.

Animals↗
PubMed1990

Transforming growth factor-beta and ovarian carcinoma cells: regulation of proliferation and surface antigen expression.

Transforming growth factor-beta (TGF-beta) is a multifunctional peptide regulating several processes in ovarian cells. The growth of ovarian carcinoma cell lines (OVCAR-3, HTB-77, 2780 and CRL-1572) was reduced by TGF-beta in a dose related manner. The antiproliferative activity was not improved by combination with other biological response modifiers. Treatment with TGF-beta augmented the expression of interferon-gamma induced class I and II antigens of the major histocompatibility complex. The presentation of another antigen namely the tumor marker CA-125 on the cell surface was markedly reduced by TGF-beta.

Antigens, Neoplasm↗
PubMed1990

The diagnostic validity of the serum tumor marker phosphohexose isomerase (PHI) in patients with gastrointestinal, kidney, and breast cancer.

The diagnostic validity of the glycolytic enzyme phosphohexose isomerase (PHI) as a serum tumor marker was evaluated. For this purpose the sensitivity of PHI was determined in 435 patients with histopathologically defined, malignant gastrointestinal, kidney, and mammary tumors prior to primary treatment. To assess the specificity, PHI serum activities were measured in 181 patients with benign diseases and disorders from an internal practice. In gastrointestinal and kidney cancer, PHI reached an overall diagnostic sensitivity of about 70%, and a specificity of 92% was obtained. Even in early stages without metastasis, elevated PHI serum levels were found in about 60% of the patients. In mammary cancer, however, a sensitivity of only 40% was observed. PHI activity can be measured without the need for highly technical skills and equipment, in a short time and at low cost. These data suggest that serum PHI can be a useful indicator in the preventive checkup of gastrointestinal and renal cancer in medical practice.

Biomarkers, Tumor↗
PubMed1990

[Use of blood components in 30 liver transplantations at the Hamburg Eppendorf University Clinic 1984 to 1989].

Among all major organ transplantations, orthotopic liver transplantation (LTX) requires the most extensive blood component support. From 1984 till 1989 we performed 30 LTX procedures on 27 patients. The number of blood components used totalled 1,000 units of packed red cells (RBC), 966 units of fresh-frozen plasma, 246 units of whole blood, 170 units of random-donor platelet-rich plasma and 71 units of platelet concentrates from cell separator. Three retransplantations were performed within 2 days after the first LTX. The lowest use of blood components was registered in patients with hepatoma, the highest in alcoholtoxic cirrhosis. Ten of the 27 patients are still alive.

Blood Transfusion↗
PubMed1990

Modified lysosomal compartment as carrier of slowly and non-degradable tracers in macrophages.

A previous immunocytochemical study of macrophages infected with Bacillus subtilis showed that a cell wall antigen could be detected for several days in a population of small vesicles randomly distributed within the cells and apparently distinct from perinuclear lysosomes. These observations suggested the possibility that these vesicles might constitute a "storage" compartment for non-degradable compounds. In the present report we compared in pulse-chase experiments the location and fate of a series of degradable and non-degradable pinocytic tracers within the macrophages. The tracers, detected by fluorescent microscopy, were bovine serum albumin (BSA), hen egg ovalbumin (OVA), horseradish peroxidase (HRP). Lucifer Yellow, fluorescent dextran, and levan. BSA and OVA remained located in perinuclear lysosomes during the chase period until their disappearance occurring within 3 h. In contrast, the other tracers, although initially located in perinuclear lysosomes, were found after a 3 to 5-h chase in small vesicles homogeneously distributed in the macrophage cytoplasm where they remained visible for 2 to 3 days. The use of markers for different cell organelles indicated that these dispersed vesicles exhibited several of the lysosomal features. They were acidic, they contained the 100 kDa and the 120 kDa lysosomal proteins as well as some acid proteases albeit these markers were in lesser concentrations than in the perinuclear lysosomal compartment. The addition of bacteria to the macrophages previously loaded with fluorescent dextran showed that all dispersed vesicles have the same fusion property as lysosomes and that slowly degraded or non-degradable tracers turn over through the perinuclear lysosomal compartment by using the endocytic pathway. Measurement of the release of some of the tracers into the culture medium suggested that the "dispersed vesicles" were probably not implicated in exocytosis of the tracers.

Animals↗
PubMed1990

[Sleep and hypertension. An epidemiologic study in 7,901 workers].

In order to evaluate possible correlations between blood pressure levels and sleep quality, 7,901 workers of both sexes living in Paris area have been the subject of a survey during their annual examination performed by workside physicians. The enquiry included questions related to sleep quantity and quality, sleeping pills consumption, awakenings, nightmares, snoring, way of life and working conditions. The information concerning these parameters was available for 7,542 people. Among them, 6,551 (86.9%) did not suffer from high blood pressure (HBP) (blood pressure less than 160/95 mmHg), 618 (8.2%) presented a high blood pressure but were not treated, 371 (4.9%) received a treatment against HBP. The average sleep duration is about 7.4 h (S.D. = 1.0) for men and about 7.6 h (S.D. = 1.0) for women (less than 0.001). It is significatively and negatively correlated with the systolic blood pressure level (SBP) (less than 0.001) and the diastolic blood pressure level (DBP) (less than 0.001). The frequency of patients complaining of nightly awakening and of snoring significatively increase with SBP (p less than 0.05) and DBP (p less than 0.001). The observed association between DBP (but not SBP) and sleep duration and nightly awakening remains significant in multivariate analysis including age, sex, tobacco smoking, alcohol and coffee consumption, use of sleeping pills and hypotensive treatment, as well as the negative correlation between SBP and nightmare frequency. The correlation between SBP or SBP and snoring was no more significant. In conclusion, a significant correlation has been found between the blood pressure levels and the sleep quality whose clinical consequences remain to be explored.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗