The role of microtubules and microfilaments in the hydrosmotic response to antidiuretic hormone.

To test the effects of colchicine and cytochalasin B on the ADH-induced response, unidirectional and net water fluxes were measured at one or two minutes intervals in frog urinary bladder. The action of these agents on the appearance of intramembrane particles aggregates in the luminal membrane of target cells under oxytocin stimulation and the changes in the tissue ultrastructure induced by cytochalasin B were also studied. It was observed that: the time-course of the response to oxytocin was strongly slowed by colchicine while the washout was not affected; the time-course of the 'on and off' of the response to oxytocin was not modified by cytochalasin B; cytochalasin B pretreatment proportionally reduced unidirectional and net water fluxes measured after glutaraldehyde fixation; the combined action of colchicine and cytochalasin B proportionally reduced the net water flux and the number of intramembrane particles aggregates, observed in freeze-fracture studies; after cytochalasin B action the dilation of intercellular spaces classically observed under oxytocin stimulation is strongly reduced.

[Recurrent atelectasis disclosing a post-traumatic aneurysm of the thoracic aorta. Apropos of 2 cases].

The authors report 2 cases, in which recurrent and reversible atelectasis of the left lung was the only manifestation leading to a diagnosis of post-traumatic aneurysm of the thoracic aorta at an early stage (D + 5). Other classically described signs were absent. These 2 cases demonstrate the need to seek an aortic aneurysm following any severe trauma.

[Comparative study of 3 implanted micrografts placed in the abdominal aorta of the rat].

A comparative study was conducted on three micrografts of 2 mm diameter: a frozen umbilical artery, a bovine heterograft and an inert P.T.F.

Fusion images and intramembrane particle aggregates during the action of antidiuretic hormone. A rapid-freeze study.

Antidiuretic hormone (ADH) causes the appearance of water-conducting particle aggregates in the luminal membrane of receptor cells in amphibian bladder and skin, and in the mammalian collecting duct. The aggregates originate from cytoplasmic tubules that fuse with the luminal membrane during ADH stimulation. We have studied the process of fusion and the structure of the particle aggregates by a rapid-freeze technique that renders chemical fixation and glycerol protection unnecessary.

Apical material extracted from amphibian urinary bladder epithelium by enzymes and detergent treatment.

The apical plasma membrane of epithelial cells of frog and toad urinary bladder is subject to large modifications during the induction of water permeability by the antidiuretic hormone. A better characterization of the apical membrane is necessary for a clear understanding of the mechanisms of hormone action. Towards this end, apical material was extracted by enzymatic treatment and by incubation with detergent.

Structural and cytochemical differentiation of membrane elements of the apical membrane of amphibian urinary bladder epithelial cells. A label fracture study.

It is now generally accepted that ADH-induced increase in water permeability in responsive epithelia is associated with the insertion of specific structures in the apical membrane of epithelial cells. Up to now, these structures have only been recognized in freeze-fractured preparations and their chemical nature is still unknown. In this study, we used the label-fracture method (Pinto da Silva and Kan, J.

In vitro survey of low energy laser beam penetration in compact bone.

The laser used in this study (NEURALASE R1) is a light-emitting diode which emits continuous or modulated impulsional signals in the near infra-red (approximately 850 nm). The power emitted varies between 1 and 11 mW. The instrument is placed at a fixed distance from a photovoltaic sensor whose voltage response is a linear function of the received luminous power.

[Hemodialysis in a newborn infant with acute renal failure].

A 10-day old newborn with post-operative acute renal failure and in whom peritoneal dialysis was impossible was successfully treated by haemodialysis. The technique requires close monitoring and has some particular features, such as difficult vascular approaches, filling of the extracorporeal circuit prior to dialysis, low blood flow rate, sodium bicarbonate in the dialysis bath and high glucose intake. No major complication occurred in the 14 sessions which made it possible to overcome the acute phase of renal failure.

Fatty acid and squalene compositions of Mediterranean Centrophorus SPP egg and liver oils in relation to age.

The liver oil content of seven Mediterranean Centrophorus spp. were studied together with the oil of one unfertilized egg and one yolk bag. The relative weight of the liver ranges from 15 to 29% of total body weight; 63 to 89% of the liver weight is oil.

[Crossed iliofemoral bypass].

Crossed shunts between the two femoral axes constitute a useful safeguard in unilateral iliac occlusions when the abdominal approach is contraindicated. Hemodynamic considerations suggest the need for iliac implantation from the donor side. This simple technique does not complicate the operation and provides a more satisfactory result than the interfemoral shunt.

[Popliteal artery thrombosis from an osteochondroma of the upper end of the tibia. Apropos of a case].

A rare case of thrombosis of the popliteal artery due to an exostosis of upper end of tibia is reported. It is rare for exostoses to develop at the upper metaphysial region of the tibia, rare fore vascular complications to develop and particularly rare for these to consist of thromboses. This lesion is a differential diagnosis in young adults with lower limb ischemia.

[One complication can mask another: chance discovery of a rare lesion during screening for arthritis of the hip].

The authors report the case of a new born baby in whom at the fourth day of life, a severe hypocalcemia was discovered. An umbilical arterial catheterization was performed. The evolution was characterized by a staphylococcic septicemia with hip arthritis and partial immune deficit.