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Biomedical subjects

P Leo

Publications and source records attributed to P Leo.

At least 37 records · Page 2Linked to original sources
PubMed1993

Nephrotoxicity of human Bence Jones protein in rats: proteinuria and enzymuria profile.

The effect of intravenous administration of 80 mg purified human Bence Jones protein twice weekly for 5 weeks was investigated in male Wistar rats (N = 7; 2 months old). A state of immunological tolerance was demonstrated by the absence of a B-cell response (plaque-forming cells and hemagglutination titers) and by the absence of detectable antigen or antibody deposition in glomeruli, as indicated by light and electron microscopy. No rise in blood urea level was detected (33.9 +/- 4.3 vs 32.8 +/- 1.3 mg%). There was an increase in proteinuria (5.3 +/- 0.9 vs 32.8 +/- 4.0 mg/day), mainly due to Bence Jones protein excretion (0 vs 29.2 +/- 5.2 mg/day), with a slight but significant increase in albuminuria (0.2 +/- 0.1 vs 1.0 +/- 0.2 mg/day). There was a significant increase of lysosomal N-acetyl-beta-D-glucosaminidase in the urine (6.1 +/- 1.3 vs 72.7 +/- 18.8 mU/mg in creatinine). Lysosomal accumulation of Bence Jones protein in proximal tubular cells was evidenced by immunoelectronmicroscopy with protein A-gold. These results clearly showed proximal tubular dysfunction induced by chronic Bence Jones protein administration, without interference of autologous immune response as demonstrated by immunological state of tolerance.

Animals↗
PubMed1993

[Comparison of magnetic resonance (0,5 T), computed tomography, and endorectal ultrasonography in the preoperative staging of neoplasms of the rectum-sigma. Correlation with surgical and anatomopathologic findings].

Eighteen cases of rectal carcinoma were staged preoperatively with transrectal endosonography (EUS), CT and MRI (0.5 T). The results were compared with surgical specimens and histology to evaluate the accuracy of the imaging modalities in staging rectal carcinomas which had been quantified according to Astler-Coller's classification. All methods identified the lesion (100% sensitivity). EUS and MRI correctly staged 8 cases (44%) and CT 9 cases (50%). CT and MRI mistakes were relative to overstaging, whereas EUS understaged 4 cases (22%) and overstaged 6 cases (33%). In local tumor staging ("T" variable), CT and MRI understaged no lesions, thus exhibiting 100% sensitivity, which was higher than EUS sensitivity (92%). Conversely, CT and MRI more frequently overstaged the lesions, thus demonstrating lower sensitivity than EUS (55% and 50%, respectively, versus 76% for EUS). As for the "N" variable, EUS identified node metastases in one case only (25%) and misdiagnosed as positive 4 cases of negative node involvement. All the C-stage lesions were correctly diagnosed by CT and MRI (whose findings were in agreement) which also overstaged as C three cases with hyperplastic node enlargement. The diagnostic accuracy of EUS, which was highest for the A and B1 stages, progressively decreased for bigger lesions, clearly understaging node involvement. On the contrary, CT and MRI accuracy rates were lower in small tumors involving the rectal wall only, whereas they always identified tumor spread beyond the bowel wall into perirectal fat, and node metastases. Therefore, to conclude, EUS can be used first: in case of extraluminal tumor spread, CT is the method of choice, more accurate than MRI in identifying node involvement and equally effective in evaluating perirectal fat infiltration and pelvic structures involvement. Whenever the pelvic floor is involved, MRI is the best imaging method, thanks to its multiplanar capabilities, for better detailing of musculoskeletal involvement.

Aged↗
PubMed1991

Natural history of hepatic haemangiomas: clinical and ultrasound study.

Hepatic haemangiomas are the most common benign tumours of the liver and commonly present as incidental findings on sonographic examination of the abdomen. Since little is known of the natural course of these tumours, we performed a clinical and sonographic follow up of 123 haemangioma patients. Our prospective study investigated clinical and sonographic findings in 158 haemangiomas for periods of 12 to 60 months. Ninety nine haemangiomas measured less than 2 cm and had an echogenic pattern; 40 were between 2 cm and 5 cm with a mainly echogenic structure; 19 measured greater than 5 cm and showed a mixed echo pattern. At the first examination only eight patients, all with giant haemangiomas, presented symptoms which could be attributed to the tumour. During follow up only one haemangioma changed in shape and size. One patient who was symptom free at the first examination experienced right upper abdominal quadrant pain during follow up. No deterioration occurred in any of the patients with symptoms at the first examination, and all had a satisfactory quality of life. No complications arose during the follow up period. This study shows that in adults haemangiomas remain stable in size and echo patterns rarely change. Only haemangiomas greater than 5 cm may cause symptoms. Prolonged clinical and sonographic follow up of small and medium sized haemangiomas is not warranted.

Adult↗
PubMed1990

[Echographic study of cryptorchidism].

The authors, after a nosologic review of cryptorchidism, illustrate their positive diagnostic experience with ultrasound. Limits as well as clinical advantages, in relation to the diagnosis and follow-up, are also described.

Adolescent↗
PubMed1989

[Fowler-Stephens orchidopexy].

The authors, after a short report on intraabdominal cryptorchidism and its surgical problems, illustrate the Fowler-Stephens' technique with its advantages as they result from their experience, although limited. Some operative stages, considered essential, are emphasized.

Child↗
PubMed1988

Alleviation of scopolamine amnesia by different retrieval enhancing treatments.

Mice were trained in a one-way active avoidance task to a criterion of 9/10 avoidances. Immediately following training they were injected with scopolamine hydrochloride (1 mg/kg SC) or with saline. Retention was assessed 3 days after training by 5 test trials on which the UCS was not present. Thirty min prior to the test, groups were injected with different doses of arecoline, d-amphetamine sulphate or with saline. Other scopolamine-treated mice were exposed to the CS or the UCS 24 hr prior to the test. The scopolamine-induced amnesia was attenuated by both 0.5 and 1.0 mg/kg arecoline and by 2.0 mg/kg d-amphetamine. Retention was also improved by exposure to the CS and the UCS. These data show that scopolamine amnesia can be alleviated by treatments which activate retrieval processes.

Amnesia↗
PubMed1988

Attenuation of forgetting by pharmacological stimulation of aminergic neurotransmitter systems.

Mice were trained in one-way active avoidance to a criterion of 3/4 avoidances and tested under extinction conditions one week later when substantial forgetting had occurred. Thirty min prior to testing animals were injected with either saline or different doses of drugs which activate the noradrenergic (phenylephrine, salbutamol, clonidine) dopaminergic (L-dopa(Sinemet) transdihydrolisuride, apomorphine) and serotonergic (fluoxetine, 5-methoxy DMT) neurotransmitter systems. Results showed that all agents alleviated forgetting in a dose dependent fashion. Untrained mice treated with the most effective dose of representative drugs from each class did not exhibit avoidance behavior at testing indicating that the improved performance of trained animals was probably not the result of increased activity or other non-memorial effects of the drugs. It was concluded that pharmacological agents which stimulate monoamine systems may improve memory retrieval by activating a non-specific neural system which controls arousal, attention and motor readiness.

Animals↗
PubMed1988

Strength of scopolamine-induced amnesia as a function of time between training and testing.

Variations in the strength of scopolamine-induced amnesia as a function of age of the habit were studied in Swiss Webster mice. Animals were trained in an active avoidance task to a criterion of 9/10 avoidances and immediately following training injected with scopolamine hydrochloride (1.0 mg/kg) or saline. Retention of the avoidance learning was evaluated by testing different groups of animals 1, 3, 7, 10, 14, and 28 days following training. The retention test consisted of five trials in which the CS but not the UCS was presented. Results indicated that saline-treated mice exhibited near-perfect retention up to 14 days post-training with forgetting beginning to be apparent at 28 days. Scopolamine treatment produced strong amnesia in animals tested 1 and 3 days post-training but normal retention in animals tested 7 and 10 days after learning. The amnesia abruptly reappeared at 14 days after which time it remained stable. The marked similarity of the scopolamine retention curve to changes in the strength of memory of discrimination learning in undertrained rats reported by Deutsch suggested that scopolamine resulted in the storage of a weak memory of the avoidance response. To explore this idea further we trained mice to a criterion (4/5) which would result in a weak avoidance response and tested different groups 1, 3, 10, 14, and 28 days following learning. Results showed that strength of the memory of avoidance learning increased up to 10 days and then decreased abruptly at 14 days thus replicating the general shape of the retention curve produced by injecting scopolamine following strong training. These data suggest that scopolamine disrupts processes essential for the formation of durable memories.

Animals↗
PubMed1987

Echo-guided fine-needle biopsy of pancreatic masses.

Aim of this study was the evaluation of percutaneous echo-guided fine-needle biopsy in the diagnosis of focal lesions of the pancreas. In patients with masses of the pancreas 43 echo-guided fine-needle punctures have been performed. In 27 of the 30 cases of cancer, echo-guided puncture allowed aspiration of cells revealing malignancy. In the remaining three cases the histology was normal. Malignancy was not detected in the aspirate of any of the 13 cases of benign solid masses. In one of these patients we failed to obtain sufficient material for the purpose of diagnosis. The sensitivity of the method was 90%, the specificity 100%, and the diagnostic accuracy 92.8%. Positive and negative predictive values were 100 and 75%, respectively. No complications worthy of note occurred.

Adenocarcinoma↗
PubMed1985

Indications for laparoscopy before and after the introduction of ultrasonography.

We compared the outcome of laparoscopy performed from 1973 to 1974, prior to the introduction of routine ultrasound diagnostics, with that of examinations during the period 1980-1981 when ultrasound had become a well-established technique in the diagnosis of hepatic lesions. Our data reveal statistically significant changes in the use of laparoscopy in the diagnosis of cholestasis and tumors of the hepatic parenchyma. Laparoscopy now has fewer indications in the study of the jaundiced patient with suspected extrahepatic cholestasis which is easily identified at ultrasound. Given the high sensitivity and specificity of ultrasonography in detecting metastases, laparoscopy has become a secondary examination. However, there has been an increase in the use of laparoscopy to identify benign hepatic lesions, particularly hemangiomas.

Biliary Tract Diseases↗
PubMed1985

Demonstration of cytokeratins by immunoperoxidase staining in prostatic tissue.

The presence and distribution of cytokeratins (CK) have been investigated using an epidermal keratin antiserum in various dilutions and the PaP (peroxidase-antiperoxidase) and avidin-biotin-peroxidase (ABC) immunohistochemical methods. A total of 44 samples of prostatic tissue were divided into alcohol-fixed (22 cases) and formaldehyde-fixed (22 cases). Each group included 12 non-malignant lesions (hyperplasias and prostatitis) and 10 adenocarcinomas. The best results were achieved with the ABC method in alcohol-fixed tissues, while formaldehyde-fixed tissues gave poor staining despite the use of different enzymes to unmask antigenic determinants. With similar dilutions of the specific antiserum the PaP method gave less intense staining. Cytokeratins were detected in basal and columnar cells, in areas of transitional and squamous metaplasia and in normal transitional epithelium. Columnar cells showed strong staining in the supranuclear portion. Adenocarcinomas gave positive staining for cytokeratins varying from weak to strong. The intensity of staining showed no correlation with the degree of differentiation of the tumor. Different degrees of intensity were frequently observed within the same tumor. High dilutions of the specific antiserum (greater than 1/400) failed to stain carcinomas or stained them poorly, whereas they still stained normal or hyperplastic tissues. Gland-forming tumors showed a highly polarized labelling with the strongest staining in the luminal portion of the cell. The conclusion is that all epithelial prostatic tissues, benign and malignant, express cytokeratins.

Adenocarcinoma↗
PubMed1983

The value of ultrasonography in the diagnosis of hepatic haemangiomas.

The following ultrasonographic (U.S.) patterns were observed in 21 cases of proven hepatic haemangiomas: 1) Hyper-echoic (6 cases); 2) Hypo-echoic (4 cases); 3) Complex (11 cases). Several characteristic aspects of the echo structure (uneven appearance and fine internal parallel echoes) and the location of the lesion (para-caval or sub-diaphragmatic) may be useful for differential diagnosis with malignant neoplasia. The U.S. findings of a further 17 cases of hyperechoic focal lesion of the liver are reported. Although a definitive diagnosis was not possible in these subjects, the U.S. characteristics which remained unchanged for over 6 months, made the diagnosis of haemangioma highly likely.

Adult↗
PubMed1983

[Endoscopy findings in gastroduodenal pathology in a group of welders].

Fourteen welders were examined with the purpose to evaluate the incidence and the type of pathologic changes of the gastrointestinal tract due to the exposure to welding fumes. The medical examination was followed by endoscopic and bioptic study of gastric and duodenal mucosa. The results show the presence of pathologic changes, mainly of flogistic type, in all the microscopic investigations, although the appearance of the mucosa was generally normal. Moreover, the results of this investigation suggest that pathologic changes of gastrointestinal tract could precede those of the respiratory tract.

Adolescent↗