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Biomedical subjects

L Bianchi

Publications and source records attributed to L Bianchi.

At least 253 records · Page 14Linked to original sources
PubMed1993

Performance evaluation of a hand-held gamma detector probe used for radioimmunoguided surgery.

The success of radioimmunoguided surgery (RIGS) is dependent on the performance parameters of the apparatus, its correct handling, and the employment of a suitable radioactive compound. In the present study the authors examined the performance of the Neoprobe 1000 device with respect to the radioisotope 99mTc. Detecting efficiency was evaluated experimentally using a phantom containing a radioactive point source which could be moved both vertically and horizontally with respect to the central axis of the probe. In this way curves representing the variations in efficiency as a function of the vertical and horizontal distances of the source from the probe were constructed. Furthermore, values of minimum detectable activity as a function of source depth, counting time and background radioactivity were calculated. These results were compared to those previously obtained using 125I, the radioisotope most frequently employed in RIGS. The graphs and tables included could serve as a practical aid to help the operator obtain the best possible measuring conditions, thereby maximizing his/her results.

Humans↗
PubMed1992

Ethinylestradiol increases volume and decreases sinusoidal membrane surface in the rat liver: a stereological analysis.

Structural alterations of liver parenchyma caused by ethinylestradiol, a synthetic estrogen known to induce cholestasis and to act as a tumor promoter factor, were investigated. Male rats treated with 17 alpha-ethinylestradiol (5 mg/kg body weight for 5 days) were compared with controls (n = 5 each). After perfusion fixation and systematic random sampling, paraffin sections, semithin sections and thin sections were examined observing standard stereological techniques. Ethinylestradiol treatment induced an increase in liver volume by 65% (p less than 0.001), which was caused more by hypertrophy (volume of singular hepatocyte +35%, p less than 0.001) than by hyperplasia (number of hepatocytes +23%, p less than 0.001). A decrease in sinusoidal membrane surface density (-43%, p less than 0.005) associated with a decrease in sinusoidal microvillar volume density (-50%, p less than 0.005) were both compensated for by the increase in liver volume. No canalicular alterations were observed. Thus changes in hepatocytes detectable with stereological techniques affect the sinusoidal pole where decreased sinusoidal membrane surface is associated with or reflects a substantial loss of membrane phospholipids. The increased liver volume may constitute an adaptive response compensating for the relative decrease in sinusoidal membrane surface and displays characteristics comparable to those of preneoplastic hepatocytes.

Animals↗
PubMed1992

Polymerase chain reaction detects hepatitis B virus DNA in paraffin-embedded liver tissue from patients sero- and histo-negative for active hepatitis B.

The polymerase chain reaction (PCR) was used to analyse tissues from paraffin blocks of liver needle biopsies retrospectively. Biopsies of 29 patients with proven HBsAg and HBcAg expression in liver tissue and of 8 healthy volunteers served as positive (group 1) and negative tissue controls (group 2), respectively. These were compared with 16 patients with proven HBsAg expression in liver but lack of HBcAg (group 3), with 23 patients with anti-HBc as the only hepatitis B virus (HBV)-related marker (group 4) and with 21 patients with liver disease and without HBV markers in tissue or serum (group 5). PCR detected HBV sequences in all cases of the positive control group and in 94% of group 3, in 65% of group 4, and in 71.4% of group 5, whereas all healthy volunteers were negative. Our data show that PCR is able to detect HBV-DNA sequences in virtually all patients with active viral antigen expression but also in a high proportion of hepatitic patients who are silent for active HB but may or may not show signs of a contact with the HBV. Thus, PCR for HBV-DNA in paraffin sections might become a useful tool for identifying patients carrying HBV-DNA but not expressing HBV antigens.

Base Sequence↗
PubMed1992

Hepatitis B X-gene expression in hepatocellular carcinoma.

A RNA-PCR method and different sets of primers were used to investigate the expression of different hepatitis B (HB) virus genes at the RNA level. We tested paired samples (tumor and non-tumor) from the liver tissues of 48 Taiwanese patients with primary hepatocellular carcinoma (HCC). By using a set of primers which spanned the sequences of the S-gene, we found expression in only 2 patients. In one HBs-RNA was only detected in the tumor tissue and in the other only in the surrounding non-tumor tissue. Using primers covering the C-gene, expression was found in 7 patients. In 2 of these RNA was detected in both the tumor and the surrounding tissue, in 2 in the tumor tissue, and in 3 in the surrounding tissue only. Finally, when primers spanning the X-gene sequences were used, RNA was detected in 40/48 patients. In 33 of these cases HBx-RNA was detected in both tumor and non-tumor tissue, in 3 patients in tumor tissue only, and in 4 in the surrounding tissue. Among the cases in which HBc and HBs-RNA was expressed, all showed HBx expression also. These data indicate that the expression of the HBx gene in HCC may play an important role in hepatocarcinogenesis.

Base Sequence↗
PubMed1992

The efficacy and tolerability of cyclosporine G in human kidney transplant recipients.

Twelve consecutive first cadaveric kidney transplant recipients received cyclosporine G (CsG)(initial dose 12 mg/kg per day) as basic immunosuppressive treatment along with prednisone (initial dose 0.5 mg/kg per day) for the first three months after transplantation. Thereafter CsG was replaced by Sandimmun (cyclosporine, CsA). Evaluation of the immunosuppressive efficacy and assessment of possible side effects of CsG was made and compared with the results in 38 historical control patients starting with the same dose of CsA as part of the same immunosuppressive dosage schedule. Statistically, there was no difference in patient survival at three (91% in CsG group versus 95% in CsA group) and twelve months (91% in CsG group versus 92% in CsA group), or in graft survival at three (75% in CsG group versus 89% in CsA group) and twelve months (75% in CsG group versus 84% in the CsA group). At equivalent oral doses of CsG and CsA significantly higher blood levels of CsG were observed (2P less than 0.05). Nephrotoxicity assessed by graft biopsy could be demonstrated to a similar extent in both groups, whereas hepatotoxicity was more pronounced during CsG treatment. Sequential measurements of bilirubin revealed a significant increase in all patients but median values were significantly higher in the CsG patients. A pronounced and concordant elevation of liver enzymes occurred during CsG treatment in three out of 12 patients. Liver biopsies performed in these patients revealed histological alterations consistent with toxic liver injury. Thus, in human kidney transplant recipients CsG and CsA appeared to be equally immunosuppressive and nephrotoxic but more hepatotoxic. On the basis of this limited experience we conclude that in human kidney transplant recipients CsG has no advantage over CsA.

Adult↗
PubMed1991

[Aspiration cytology in the diagnosis of renal transplant rejection].

BACKGROUND: The use of fine needle aspiration for the diagnosis of renal transplant rejection is advantageous for its innocuousness, thereby making it an acceptable method for monitoring. However, the clinical use reported among several groups has been variable and indeed, the influence it may have on the results of the use of different lines of immunosuppressors is little known. METHODS: Thirty-six consecutive renal transplanted patients were studied prospectively over the 2 months following the transplantation of the organ. The basal immunosuppressor treatment consisted in the administration of prednisone and antilymphocytic serum in patients presenting acute post-transplant tubular necrosis with the remaining patients receiving cyclosporin in monotherapy. One hundred seventy-three double punction were carried out. RESULTS: No complications were observed as a consequence of the punction. The material obtained was insufficient for evaluation on 18 occasions. The use of the method for diagnosis of rejection obtained a sensitivity and specificity of 73% and 81% respectively. Furthermore, in the group of patients with stable renal function, higher immunoactivation indexes were observed in those treated with cyclosporin in monotherapy (1.7 +/- 1.7) with respect to those who received triple treatment (0.5 +/- 0.4). CONCLUSIONS: The use of fine needle aspiration cytology is safe and clinically useful in the monitoring of the post renal transplantation period. The results should be interpreted in terms of different immunosuppressive lines.

Adolescent↗
PubMed1991

[Multicystic chylous lymphangioma in the mesentery of the small intestine].

In the search for metastases computed tomography and ultrasonography of the abdomen were performed in a 47-year-old man with a known malignant melanoma in the left lower leg. Numerous fluid-filled cavities, about 8 cm in diameter, were an incidental finding. He died two years after diagnosis of the melanoma, which had extensively metastasized. At autopsy a large multicystic tumour (21 x 15 x 8 cm) was found in the mesentery of the small intestine. The cysts were filled with chyle. Histologically they proved to be multicystic lymphangiomas. Mesenteric lymphangiomas are very rare, multicystic ones and manifestation in adults even more so.

Brain Neoplasms↗
PubMed1991

Utility of pulsed Doppler in the diagnosis and follow-up of acute vascular graft rejection treated with OKT3 monoclonal antibody or antilymphocyte serum.

Fifteen patients with severe acute vascular graft rejection (twelve of them steroid-resistant) treated with OKT3 monoclonal antibody (8) or antilymphocyte serum (7) were sequentially studied with duplex-Doppler ultrasonography (DDUS). Measurements of intrarenal resistance were obtained by means of the resistive index (RI). During rejection episodes, the intrarenal resistance was increased in all patients (RI range: 0.89-1), with absent or reversed diastolic blood flow. Normalization of diastolic blood flow was documented prior to the decrease of serum creatinine level in all patients who recovered from a rejection episode. We conclude that DDUS is a noninvasive technique useful in the diagnosis and monitoring of acute vascular graft rejection. Prediction of graft outcome after rejection treatment could probably be made based on DDUS findings.

Adult↗
PubMed1991

The importance of "temporal pattern" in traumatic impulse noise exposures.

The equal energy hypothesis (EEH) was evaluated for impulse noise. Specifically, the experiments evaluated the importance of the temporal distribution of impulses; the trading relation between the number of impulses and peak level and the difference between continuous and impulse noise. Monaural chinchillas were exposed to one of seven conditions. Their hearing was evaluated before, immediately after, and 30 days after the exposure. Hair cell damage was reported in the form of a cochleogram. The experiments show that the EEH is more appropriate for low-level impulse (135-dB peak); for equal amounts of energy, 150-dB impulses produce more hearing loss and hair cell damage than 135-dB impulses; for equal amounts of energy, impulses presented in rapid bursts cause less damage than impulses presented at "1/s" and 50 microseconds. Pairs of impulses presented at "1/s" produce the largest amount of damage. The results are discussed in terms of implications for the EEH.

Animals↗
PubMed1990

Bile duct ligation-induced redistribution of canalicular antigen in rat hepatocyte plasma membranes demonstrated by immunogold quantitation.

Extrahepatic obstructive cholestasis has been demonstrated to induce a redistribution of domain specific membrane proteins in rat hepatocytes reflecting loss or even reversal of cell polarity. In order to further characterize the redistribution of canalicular antigens, we used the Lowicryl K4M immunogold technique for examination of the effects of bile duct ligation (50 h) on the distribution of antigen in rat hepatocytes at the ultrastructural level and quantitated immuno-gold density in the three domains of the plasma membrane. In normal hepatocytes, antigen was localized almost exclusively in the canalicular domain while the sinusoidal and lateral membranes showed only weak immunoreactivity. Other localizations included organelles compatible with known pathways of biosynthesis and degradation. Bile duct ligation markedly reduced immunolabel in the canalicular and increased it slightly in the sinusoidal domain. The number and staining intensity of immunoreactive subcanalicular lysosomes and vesicles probably representing endosomes was augmented. Number of immunogold particles per micron of plasma membrane were 7.86 vs 2.46 (P less than 0.005) in the canalicular, 1.16 vs 1.38 (n.s.) in the sinusoidal, and 1.23 vs 1.08 (n.s.) in the lateral domain resulting in a canalicular decrease by 68.7% and a sinusoidal increase of 19.0%. Overall decrease in total plasma membranes was by 29.7% (P less than 0.05). Thus, our data show that the sinusoidal and lateral domains behave differently. Furthermore, quantitative immunocytochemistry demonstrates a decrease in the canalicular antigen density and suggests a sinusoidal increase. The present data agree with the concept that bile duct ligation results in a loss or even reversal of cell polarity in hepatocytes.

Animals↗
PubMed1990

Hepatic expression patterns of the large and middle hepatitis B virus surface proteins in viremic and nonviremic chronic hepatitis B.

The envelope of hepatitis B virus consists of large, middle, and small hepatitis B surface proteins. Recent data from in vitro studies suggest that intracellular expression and distribution of the three polypeptides may be variable. These observations in artificial expression systems prompted this analysis of the occurrence and distribution of the three hepatitis B surface proteins in the liver tissue of substantial viremic (hepatitis B virus DNA- and hepatitis B e antigen-positive) and low-viremic or nonviremic (hepatitis B virus DNA-negative, anti-hepatitis B e antigen-positive) carriers by specific monoclonal antibodies against large, middle, and small proteins. Patients with an active form of viral replication showed a prevalence of middle and small hepatitis B surface proteins in the liver. In nonviremic carriers, the large hepatitis B surface protein was the predominant intrahepatic antigen, a finding that was confirmed at the ultrastructural level by staining of the entire filaments of the viral envelope material in ground glass hepatocytes. The present data are thus consistent with observations in hepatitis B virus-transgenic mice and in transfected cell systems, suggesting that the different patterns of the envelope proteins in the liver may be due to different processing at the translational level.

Antibodies, Monoclonal↗