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Biomedical subjects

R Lambert

Publications and source records attributed to R Lambert.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Ultrasonoendoscopy: its indications in esophageal and gastric pathology].

Endoscopic ultrasonography (EUS), which uses a high sonographic frequency (7.5 mHz) is a recently developed diagnostic tool that enables detailed analysis of the digestive wall and visualization of adjacent structures, like the posterior mediastinum through the esophagus. Thus, EUS may provide accurate documentation of the extent of esophagogastric malignancies, and of the adjacent lymph-node involvement. From now, results in preoperative staging compare favourably with CT scan. EUS provides also helpful complementary informations for the diagnosis of giant fold gastropathies or submucosal (or extrinsic) abnormalities. Moreover it may be usefull for the post-therapeutic follow-up of cancers, ulcers or varices.

Esophageal Diseases↗
PubMed1987

Glomerular epithelial cell lesions in rat renal isografts.

Visceral glomerular epithelial cell lesions--microvillus formation, loss of foot processes, osmiophilic inclusion droplets, balloon-like malformation of cell processes, degeneration, necrosis, and loss of cell processes from capillary basement membranes--are found in rat renal isografts 1 mth after transplantation. The lesions, which are most readily recognized in perfusion-fixed material, are essentially focal, affecting neither all glomeruli, nor all cells in any glomerulus, bear no relation to the degree of interstitial nephritis in the graft, and are associated with albuminuria and with focal capillary sclerosis in some glomeruli. They are not restricted to renal isografts but are found in aging rats, in different experimental models of glomerular disease and in clinical glomerular disorders, again in association with proteinuria and glomerulosclerosis. It is therefore proposed that glomerular epithelial cell damage increases capillary permeability and impairs maintenance of the integrity of the capillary wall, leading to proteinuria and focal glomerulosclerosis.

Animals↗
PubMed1987

Conjugated and unconjugated C-21, C-19 and C-18 steroid concentrations in human follicular fluid from hyperstimulated follicles.

Concentrations of unconjugated and glucuronated C-21, C-19 and C-18 steroids have been measured in follicular fluid obtained from women hyperstimulated by a combination of clomiphene citrate, pergonal and hCG. Pregnenolone and its glucuronide are found at approximately 5% of the progesterone values (14,395 +/- 2300 ng/ml). Concentrations of dehydroepiandrosterone glucuronide, androst-5-ene-3 beta, 17 beta-diol glucuronide, dihydrotestosterone glucuronide, androstane-3 alpha, 17 beta-diol glucuronide and androstane-3 beta, 17 beta-diol glucuronide are 2-6-fold higher than those of the related unconjugated steroids, while testosterone glucuronide levels are lower than those of testosterone. The concentrations of androsterone glucuronide reach almost 30-fold those of androsterone (2.56 +/- 0.35 ng/ml). By contrast, estradiol and estrone concentrations are 10-20-fold higher than those of conjugated steroids. Measurement of plasma steroid glucuronides indicated that the concentrations in circulation are markedly lower than those detected in follicular fluid. Our data suggest that the ovary in humans may be a site of glucuronidation.

Chorionic Gonadotropin↗
PubMed1987

[Laser treatment of villous rectal tumors].

The treatment of villous rectal tumors with the Nd: YAG laser is characterized by its great effectiveness (almost 90% of complete eradication in our series of 100 cases), and by its great tolerance. It may be applied to all patients regardless of their condition. In case of running villous tumors, complete destruction is more difficult to obtain and the laser method must be weighed against the risks and advantages of radical surgery. The problems raised by frequent foci of adenocarcinoma, which characterize large villous lesions, is minimized by a strict therapeutic protocol: in fact, the foci are superficial in the majority of the cases and they do not decrease the percentage of complete destruction; in other cases, it is possible, by repeated histological controls, in case of persisting positive biopsies, to modify, in time, the choice of treatment.

Adenoma↗
PubMed1986

Occurrence of a nucleoprotein bound RNase in rat brain and liver.

An RNase activity was found to be present in rat brain and liver and was strongly bound to the nucleoprotein fractions of these tissues. It could not be solubilized by treatment with acid or by lipid solvents. The pattern of oligonucleotides produced during hydrolysis by this enzyme indicated that it was probably an endonuclease with restricted specificity. It was inhibited by zinc ions and by low pH.

Animals↗
PubMed1986

Memory formation in birds: 1. Avoidance conditioning of the budgerigar (Melopsittacus undulatus) to sound stimuli.

A system is described for avoidance conditioning of the budgerigar (Melopsittacus undulatus), for sound patterns consisting of one or two sequential subunits and to discriminate between two closely resembling sounds. Electric shock was used as the unconditioned stimulus. Simple conditioning was accomplished in about 300-400 trials. After a given sound pattern was firmly fixed by conditioning, discrimination between this and a new sound pattern was established relatively rapidly by using several consecutive sessions in which the two patterns were mixed. Discrimination was reinforced by associating the two signals by opposing electric shocks. An overnight rest period after the first few sessions improved the rate of conditioning during the following experimental period. A temporary, partial or complete extinction of conditioning was produced by longer rest intervals, but the original conditioning was reestablished by subjecting the animal to a few trials of reconditioning. Short intercalations of a new conditioned stimulus had no effect on the retention of the original conditioning whereas a random mixing of the first conditioned stimulus with a second produced a temporary decay in the original conditioning. The experimental system described here is useful for studying physiological and biochemical changes accompanying a memory process based on a linear sequence of sound patterns.

Animals↗
PubMed1986

Memory formation in birds: 2. Effects of stress due to experimental procedures on the conditioning of the budgerigar (Melopsittacus undulatus) to sound stimuli.

Conditioning studies involving administration of biochemical or pharmacological agents are often stressful to experimental animals. Some of these stressful manipulations were examined for their effect on the avoidance conditioning of the budgerigar to sound stimuli. There were individual variations in the capacity of the birds to accommodate to these stresses, but generally the stress factors had negative effects on their subsequent conditioning, the degree of this effect depending upon the type and severity of stress. Simple anesthesia with ether had the least effect, intravenous injection being next in severity, while intracerebral injection was most inhibitory. The effects due to anesthesia and intravenous injection could be decreased by delaying the conditioning procedure for 1 to 2 hours following the treatment, but the effect of intracerebral injection was more prolonged. The retrieval of temporarily lost conditioned response through brief reconditioning was not affected by intracerebral injection, indicating that, once a memory trace was formed, subsequent emotional and physical stresses did not obliterate it irreversibly.

Animals↗
PubMed1986

Glomerular damage after kidney preservation.

Severe proteinuria occurs during isolated organ perfusion of kidneys removed from SD and DA rats and subjected to 24-hr cold preservation. In both strains increased glomerular permeability was associated with changes in glomerular visceral epithelial cells, particularly cytoplasmic edema and detachment of cells from capillary basement membranes. Foot processes were intact and staining for sialoglycoprotein was retained. The changes were compatible with survival of the isograft kidney after transplantation, but moderate proteinuria was found in some rats after one month. Protein loss in the urine during isolated organ perfusion is very much less in kidneys subjected to 4-hr cold preservation, and the glomerular epithelial cells are normal or show only minimal cytoplasmic edema on electron microscopy. The experiment shows that significant damage to glomeruli may occur during preservation prior to transplantation, and the model itself can be usefully exploited to determine the relation between increased glomerular permeability to albumin and the associated changes in the glomerular capillary wall.

Animals↗
PubMed1986

[A triple association: rectocolonic adenomatosis, gastroduodenal polyposis and secreting adrenocortical adenoma].

A case of adenomatosis coli, gastroduodenal polyps, and functional adrenocortical adenoma in a 28 year-old woman is reported. The association of cystic fundic gland polyposis and duodenal adenomatosis was demonstrated endoscopically. The particular point of interest in this case report is the functional nature of the adrenocortical adenoma. Endocrine tumors associated with adenomatosis coli are generally discovered at autopsy. No similar case has been previously published.

Adenoma↗
PubMed1986

Gallium-67 uptake in the lung of asbestos exposed sheep: early association with enhanced macrophage-derived fibronectin accumulation.

To evaluate the time course and mechanisms of enhanced 67Ga lung uptake in asbestosis, we exposed two groups of sheep every 2 wk to either 100 ml saline (controls) or 100 mg UICC chrysotile fibers in 100 ml saline. The sheep were evaluated periodically by pulmonary function tests (PFT), thoracic radiograph (TR), 67Ga lung scan bronchoalveolar lavage (BAL), and transbronchial lung biopsy (TLB). By month 24 of the study, 9/15 exposed sheep had developed the initial alveolitis and had significant changes in PFT, TR, and TLB. The other six exposed sheep differed from controls only by a 75% increase in BAL fibronectin until month 30, where significant changes in albumin occurred and 67Ga scan score increased. The nine sheep with alveolitis had significant sustained increases in 67Ga scan and BAL levels from month 6, associated with a 150% increase in BAL fibronectin and other parameters of disease activity changed from month 18 to 30. We concluded that in the sheep model of asbestosis, significant changes in 67Ga scan, 67Ga BAL counts, and excessive elevation of BAL fibronectin preceded other parameters of disease activity. The data suggest that excessively activated macrophages are primarily responsible for the early 67Ga lung uptake.

Animals↗
PubMed1985

Gallium-67 thoracic scan and pleural disease in asbestos workers.

We have recently reported that 67Ga scanning in asbestos workers can document excessive uptake of the marker among workers without sufficient criteria for asbestosis, but in our initial report we could not exclude definitely that 67Ga uptake could be related to pleural disease. To further test this hypothesis, we analyzed the 67Ga thoracic scan in relation to profusion scores of pleural disease on chest roentgenogram and CT scan of the thorax in 171 asbestos workers. We found no significant correlation between the 67Ga lung uptake and the radiographic scores of pleural disease. We concluded that pleural plaques are not an active site of 67Ga accumulation and do not contribute significantly to the thoracic uptake of the marker.

Adult↗