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Biomedical subjects

L Texier

Publications and source records attributed to L Texier.

At least 19 recordsLinked to original sources

The murG gene of Escherichia coli codes for the UDP-N-acetylglucosamine: N-acetylmuramyl-(pentapeptide) pyrophosphoryl-undecaprenol N-acetylglucosamine transferase involved in the membrane steps of peptidoglycan synthesis.

Physiological properties of the murG gene product of Escherichia coli were investigated. The inactivation of the murG gene rapidly inhibits peptidoglycan synthesis in exponentially growing cells. As a result, various alterations of cell shape are observed, and cell lysis finally occurs when the peptidoglycan content is 40% lower than that of normally growing cells. Analysis of the pools of peptidoglycan precursors reveals the concomitant accumulation of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmuramyl-pentapeptide (UDP-MurNAc-pentapeptide) and, to a lesser extent, that of undecaprenyl-pyrophosphoryl-MurNAc-pentapeptide (lipid intermediate I), indicating that inhibition of peptidoglycan synthesis occurs after formation of the cytoplasmic precursors. The relative depletion of the second lipid intermediate, undecaprenyl-pyrophosphoryl-MurNAc-(pentapeptide)GlcNAc, shows that inactivation of the murG gene product does not prevent the formation of lipid intermediate I but inhibits the next reaction in which GlcNAc is transferred to lipid intermediate I. In vitro assays for phospho-MurNAc-pentapeptide translocase and N-acetylglucosaminyl transferase activities finally confirm the identification of the murG gene product as the transferase that catalyzes the conversion of lipid intermediate I to lipid intermediate II in the peptidoglycan synthesis pathway. Plasmids allowing for a high overproduction of the transferase and the determination of its N-terminal amino acid sequence were constructed. In cell fractionation experiments, the transferase is essentially associated with membranes when it is recovered.

Amino Acid Sequence

[Thaumetopoea pityocampa caterpillar and man. Morphology of its venom apparatus. Epidemiological investigation (author's transl)].

The combination of a mechanical phenomenon (penetration of the hair) and a chemical phenomenon (discharge of a toxic substance) accounts for the pathological symptomatalogy induced by the processional pine caterpillar. Epidemiological study has pin-pointed the regions infested by the pine caterpillar and has described in detail the dermatitis inflicted by this caterpillar with special emphasis on the frequency of ocular lesions. Also, a close correlation was noted between the geographical density of the populations of Thaumetopoea pityocampa Schiff and the geographical density of the clinical cases recorded. Skin tests have confirmed that the urticant substance is histamino-liberating. A morphological study of the urticant apparatus of this caterpillar ("mirror" and urticant hairs) was undertaken with the scanning electron microscope. The progressive coming into place of the bristles on the cuticular pads of the "mirror" was followed during the last three larval stages (L3, L4 et L5). The urticant hair, hollow on the inside, carries pointed spikes directed towards its distal end. There is no hole or pores on the hair and the necessity to grind the bristles in order to extract the urticant substance leads us to believe that the hair is really a bulb which must be broken, for example in the skin, in order to release its urticant substance (histamino-liberating).

Adolescent

[Thyroidectomy].

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Anesthesiology

[Cutaneous metastases in digestive cancers (author's transl)].

Cutaneous metastases are seldom encountered in digestive cancers. The mechanism of their formation explains their low rate. The metastases spread mainly by the lymphatic system (especially in diffuse, spotty or pseudo-elephantiasic forms and in regional forms), however numerous lymph node filters found through out the lymphatic system limit the progression of neoplasic cells. On the contrary, metastases most often spread by retrograde involvement due to blocking of the lymphatic system. As for hematogenous metastases (generalized nodular forms or aberrant localizations), they are observed even less frequently than lymphatic ones; metastatic embolisms may effectively become blocked in capillaries, especially in the lungs and the liver, which constitutes a double barrier before the skin may be involved.

Adolescent

[Treatment of the menopause].

The immediate complications of the menopause should be treated. These symptoms must be due to the menopause and the treatment should be without side effects. The object is above all to obtain a sense of well-being. More important than the immediate signs are the later trophic disorders, whether local or general. Thus a long term substitution treatment may be considered under strict supervision.

Estrogens

Ultrastructure of halo nevi.

An ultrastructural study was conducted on eight halo nevi. Some of them were of recent onset. Others had an evolution of several months. The distribution of the population of the dendritic cells in the depigmented epidermis of the halo was more polymorphous at the early stage when few melanocytes with abundant cytofilaments and some Langerhans cells were seen. At an advanced clinical stage, only Langerhans cells were present in the basal layer. In the dermis abnormal nerves as in vitiligo were observed. The inflammatory infiltrate does not seem to appear at the early stage of involution of the nevus. At the advanced clinical stage, small mononuclear cells were also noticed among the inflammatory cells (lymphocyte-like cells, macrophages, mast cells). It is suggested that an initial stage of inhibition of both the melanocytes and the nevus cells may be responsible for the development of the depigmented halo. This stage precedes the appearance of a dermal lymphomacrophagic infiltrate that leads to the destruction of the nevus.

Adolescent

[Lepromatous leprosy after BCG vaccination].

The authors describe an eruption of cutaneons nodules after a BCG vaccination. Investigation demonstrated that the lesions were caused by Lepromata. An increased number of B lymphocytes was observed in the bloodstream. Ryphampycin was used with good results.

Adolescent

[4 years of use of a linear accelerator in dermatology].

A recent acquisition in external radiotherapy, electrontherapy is the direct use of electrons which are essential in radiobiology. By their physical characteristics, the rapid fall in absorbed dosage in deep tissues, the electron beam is especially well adapted to dermatological practice. Four years use of a Bordeaux linear accelerator permitted the authors to determine the indications for the technique, its limits and practical details of its use. Carcinomas are the main indications, especially extensive lesions, advanced, relapsing, or even after other methods of radiotherapy, and in certain localisations. Wide or total irradiation raises new prospects in the treatment of hematodermia, perhaps, hope of a cure.

Electrons