PubMed Health⌕ Search

Biomedical subjects

M Barone

Publications and source records attributed to M Barone.

At least 127 records · Page 7Linked to original sources
PubMed1991

Bronchus sign on CT in peripheral carcinoma of the lung: value in predicting results of transbronchial biopsy.

The bronchus sign on CT represents the presence of a bronchus leading directly to a peripheral pulmonary lesion. We investigated the value of this sign in predicting the results of transbronchial biopsy and brushing in 33 consecutive cases of proved peripheral bronchogenic carcinoma studied with thin-slice CT (2-mm-thick sections). The bronchus sign was seen on CT in 22 patients and was absent in 11. Transbronchial biopsy and brushing showed peripheral carcinoma in 13 (59%) of 22 patients in whom the bronchus sign was seen on CT and in only two (18%) of 11 patients in whom it was not seen. The difference is statistically significant (Fisher's exact test, p = .029). When analyzed by the order of involved bronchus, a 90% success rate of transbronchial biopsy and brushing was found in patients in whom the bronchus sign was seen at a fourth-order bronchus (p = .01). This compared with a success of 33% when the bronchus sign was seen at fifth-, sixth-, or seventh-order branches. Our results suggest that the bronchus sign at a fourth-order bronchus is valuable in predicting the success of transbronchial biopsy and brushing. The presence of the sign on CT may be useful in determining if the workup should include transbronchial biopsy and brushing or transthoracic needle aspiration in patients with peripheral lung lesions.

Adult↗
PubMed1991

Cell regeneration in the pathobiology of liver carcinomas.

It is known that there is a close relationship between cirrhosis and liver cancer. The proliferative phenomena characterizing liver cirrhosis seem to be predisposing factors for carcinoma. In fact, they differ from the self-limiting proliferative phenomena occurring in normal liver regeneration because they are associated with: 1) an abnormal hormonal pattern; 2) an altered arrangement of hepatocytes and non-parenchymal cells within the lobule; 3) an altered production of growth factors able to modulate liver regeneration; and 4) an abnormal oncogene expression. Under such conditions many carcinogens, which require the target cell to be in a replicative phase, have the opportunity to act.

Carcinoma, Hepatocellular↗
PubMed1991

[Effect of precurving of canal instruments on their cutting capacity].

The author investigated the surface morphology and the cutting capability of endodontic instruments. One-hundred sixty flexofiles and 160 flexoreamers of various size, of which 40 were pre-curved by hand, 40 using hemostatic tweezers, 40 others were curved with an instrument designed for that purpose, and 40 remained unbent as a sample group, were used in the test. They were tested with a special device to determine the cutting capability. A morphological analysis of the surface was also performed with a stereomicroscope. The conclusions drawn were that pre-curving with hemostatic tweezers reduces the cutting capability by 75% for the flexofiles and by 50% for the flexoreamers doing irreparable damage to the surface structure of the endodontic instruments.

Equipment Design↗
PubMed1990

Effect of ranitidine on acetaminophen-induced hepatotoxicity in dogs.

The effect of ranitidine administration upon the hepatotoxic effect produced by a multidose acetaminophen administration regimen was examined. Seventy-two dogs received three subcutaneous injections of acetaminophen (750, 200, 200 mg/kg body wt) in DMSO (600 mg/ml) at time zero, 9 hr later, and 24 hr after the first dose. Ten control animals (group I) were not given ranitidine, the remaining 62 dogs received an intramuscular injection of ranitidine 30 min before each acetaminophen dose. Three different doses of ranitidine were used (mg/kg body wt): 50 mg, group II (33 dogs); 75 mg, group III (14 dogs); 120 mg, group IV (15 dogs). Ranitidine reduced the expected acetaminophen-induced hepatoxicity in a dose-response manner. Moreover, a significant correlation was found between the ranitidine dose and the survival rate, as evidenced by transaminase levels in the serum and histology of the liver. This model of fulminant hepatic failure induced by acetaminophen and its modulation with ranitidine provides clinical investigators with a research tool that will be useful in the future investigation of putative medical and surgical therapies being investigated for use in the clinical management of fulminant hepatic failure. Because of the size of the animal used in this model, frequent and serial analyses of blood and liver were available for study to determine the effect of therapy within a given animal as opposed to within groups of animals.

Acetaminophen↗
PubMed1989

The effect of estrogen and tamoxifen on hepatocyte proliferation in vivo and in vitro.

We have previously shown that changes in estrogen-hepatocyte interaction occur during liver regeneration. Following 70% hepatectomy, estrogen levels in the blood were elevated, the number of estrogen receptors in the liver was increased and there was an active translocation of estrogen receptors from the cytosol to the nucleus. The injection of tamoxifen, an estrogen antagonist, inhibits hepatocyte proliferation following partial hepatectomy. The administration of 1 microgram tamoxifen per gm body weight at zero time or 6 hr after the operation resulted in a significant inhibition both of DNA synthesis and of the number of cells in mitosis. Injections of tamoxifen 12 hr or later after the operation had no effect. Concomitant injections of equimolar amounts of estrogen abolished the inhibition by tamoxifen. The effects of estrogen and tamoxifen were also tested on hepatocytes in primary culture. Estrogens in the presence of 5% normal rat serum stimulated hepatocyte DNA synthesis as determined by [3H]thymidine incorporation and the labeling index, whereas epidermal growth factor-induced DNA synthesis in the absence of normal rat serum was strongly inhibited. Tamoxifen, in contrast, inhibited DNA synthesis of hepatocytes in the presence of 5% normal rat serum and reversed the stimulatory effect of estrogen in the same system. Attempts to elucidate the mechanism of tamoxifen inhibition in vitro indicated that one effect of tamoxifen is to prevent the amiloride-sensitive Na+ influx necessary to initiate hepatocyte proliferation.

Animals↗
PubMed1989

Estradiol and testosterone levels in patients undergoing partial hepatectomy. A possible signal for hepatic regeneration?

In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection.

Adult↗
PubMed1989

A dog model for acetaminophen-induced fulminant hepatic failure.

The development of a large animal model of fulminant hepatic failure produced with acetaminophen that should be useful in the development and evaluation of potential medical therapies for the important clinical problem of fulminant hepatic failure is described. Acetaminophen in dimethyl sulfoxide (600 mg/ml) given as three subcutaneous injections, with the first dose (750 mg/kg body wt) being given at noon, the second dose (200 mg/kg body wt) being given 9 h later, and the third dose (200 mg/kg body wt) being given 24 h after the initial dose consistently produces fulminant hepatic failure in dogs. The dimethyl sulfoxide vehicle, injected intramuscularly, does not influence either animal survival or hepatic function in control-treated dogs. No deaths occur within the first 36 h. By 72 h after initial drug administration, the mortality is 90%. Histopathological and biochemical investigations demonstrate a high degree of hepatocellular necrosis in nonsurviving animals without appreciable damage to the kidneys, lungs, or heart. The drug schedule and preparation outlined avoids the administration of large volumes of vehicle and results in prolonged high levels of acetaminophen in the blood sufficient to induce severe hepatic injury. Ranitidine (120 mg/kg body wt i.m.) given 30 min before each acetaminophen dose significantly reduces the mortality and hepatic necrosis produced using this model. This model satisfies all criteria established by Miller et al. for the production of a suitable large animal model of fulminant acute hepatic failure.

Acetaminophen↗
PubMed1989

Effect of cimetidine, ranitidine, famotidine and omeprazole on hepatocyte proliferation in vitro.

Recently reports have indicated that both cimetidine and ranitidine delay cell proliferation in rats following 70% partial hepatectomy and result in an increased mortality following this procedure. The present study was designed to determine whether three H2 blocking agents (cimetidine, ranitidine, famotidine) and a new, powerful antisecretory drug (omeprazole) specifically influence hepatocyte proliferation in primary culture. Hepatocytes were isolated from livers of normal male rats by the standard collagenase perfusion technique. Hepatic DNA synthesis and percent of labelled nuclei were determined after 48 h incubation. Hepatocytes in culture were incubated with the H2 blocking agents and omeprazole or with different concentrations of serum obtained from sham-operated or 70% hepatectomized rats treated or not with the same agents. Rats were injected intraperitoneally at 8:00 a.m. on two consecutive days. In hepatectomized rats, the first dose was injected at 8:00 a.m. immediately after surgery, the second, 24 h later. The serum of sham-operated or 70% hepatectomized rats that did not receive drugs served as control. No changes in DNA synthesis, percentage of labelled nuclei and transaminase were detected when the agents were added to the hepatocytes in culture at concentrations within the effective pharmacological dosage and 30 times higher. Similarly, no changes in these parameters were obtained when different concentrations of serum obtained from sham-operated rats treated with H2 blocking agents or omeprazole were added to the basal culture medium. However, a significant inhibition of DNA synthesis and of percentage of labelled nuclei was observed when hepatocytes were incubated in the presence of serum from 70% hepatectomized rats that had been treated with cimetidine or with ranitidine. The serum of 70% hepatectomized rats treated with famotidine and omeprazole had no effect on hepatocyte proliferation in vitro. No effect on transaminase was found in these conditions.

Animals↗
PubMed1989

Psychomotor dysfunctions in alcoholic and post-necrotic cirrhotic patients without overt encephalopathy.

Psychometric tests, visual reaction time tests and electroencephalograms were performed in 26 cirrhotic patients without overt portal-systemic encephalopathy and in 26 healthy individuals. Cirrhotics performed poorly, compared with controls, on intelligence, learning and memory, perceptual motor and spatial tests. Non-alcoholic scored lower than alcoholic cirrhotics compared with controls in most tests. Visual reaction time ability was lower in cirrhotics than controls, but the etiology of the cirrhosis did not influence the test results. EEG was normal in all subjects. We conclude that psychomotor tests are the most useful tool for the detection of latent encephalopathy and in the discrimination of different cirrhosis.

Adult↗
PubMed1989

[Bronchogenic carcinoma with extramucosal development. Diagnostic problems].

Bronchogenic carcinoma is characterized by three different patterns of spread: endobronchial, the commonest, submucosal, and peribronchial. While the diagnostic yield of bronchoscopy is very high for endobronchial masses, both submucosal and peribronchial tumors are more difficult to detect, and standard forceps biopsy can be negative. In such cases transbronchial needle aspiration biopsy allows higher diagnostic accuracy. CT findings of extramucosal neoplastic spread are not specific. Thickening of the bronchial walls is the commonest sign, but CT is inaccurate in predicting whether bronchial thickening will result in endobronchial/extramucosal neoplasm, fibrosis or bronchial wall edema. Despite this inaccuracy, CT is complementary to bronchoscopy since it allows to: 1) detect a pathology in the bronchial walls, which appear thickened; 2) delineate the extent of extraluminal spread; 3) help plan transbronchial needle aspiration biopsy.

Biopsy, Needle↗
PubMed1988

Dysgerminoma in 45,X Turner syndrome: report of a case.

Here we report the fourth case of dysgerminoma in a patient with the syndrome of gonadal dysgenesis and 45,X karyotype. Typical Turner's syndrome features were unusually associated with breast development, menarche and secondary amenorrhoea. Exaggerated basal and GnRH stimulated gonadotrophin and low oestradiol levels were typical of post-pubertal Turner's syndrome. Detailed (standard) chromosome and banding analysis excluded the presence of Y chromosome material. This case suggests that the presence of a Y chromosome is not necessary for abnormal differentiation of germ cells and the occurrence of a gonadoblastoma.

Adolescent↗