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Biomedical subjects

L Rossi

Publications and source records attributed to L Rossi.

At least 307 records · Page 17Linked to original sources
PubMed1990

[Importance of the wild boar in the epidemiology of wild trichinellosis in Piedmont and Liguria].

Muscle samples from 1,508 wild boars (Sus scrofa) harvested in Piedmont and Liguria between 1987 and 1990 were examined for larvae of Trichinella sp. by trichinelloscopy and peptic digestion. No wild boar was infected, though trichinellosis was present in foxes (Vulpes vulpes) from the same areas (14 positives out of 608) with the highest prevalence in the mountain range (25.0%). Infection was also not found in 40 stone martens, 5 badgers and 3 stoats. Five vulpine isolates were identified as belonging to T3 zymodeme. These results show that free-ranging wild boars, although being a source of trichinellosis infection for man in Italy (9.2% of the 584 cases diagnosed since 1961), have no significance in maintaining the sylvatic cycle of this parasite in the study area. The data agree with the low infectivity of Italian strains of fox origin for swine seen in the experimental infections carried out so far.

Animals↗
PubMed1990

[Electrocardiographic disorders in diverse clinical variations of scleroderma].

The electrocardiograms of 130 patients affected by scleroderma, 117 with systemic sclerosis (67 with diffuse and 50 with limited form) and 13 with localized scleroderma were analyzed. ECG was normal in 44.6% of cases, respectively in 39.3% with systemic sclerosis and in 92.3% with localized scleroderma. The more frequent electrocardiographic abnormalities were supraventricular and ventricular premature beats, right bundle branch block, left anterior hemiblock, low QRS voltages, ST-T wave abnormalities and Q or QS aspects. All the abnormalities above resulted to be more frequent in the patients with diffuse systemic sclerosis in comparison to the patients with limited systemic sclerosis. Our results confirm that the cardiac involvement appears to be much more serious in the diffuse systemic sclerosis.

Adolescent↗
PubMed1990

[Role of lymphangiography and abdomino-pelvic CT in uterine tumors].

Between January 1983 and December 1987, 77 patients with cervical and endometrial carcinoma (40 and 37 cases, respectively) were studied with a diagnostic protocol which included lymphangiography and abdomino-pelvic CT. The only administered treatment was radiation since all patients were considered inoperable or had non-resectable disease. Median age was 55 years (range 29-77). Median follow-up was 44 months-minimum 24, maximum 72 months. Subdiaphragmatic nodes were considered as pathologic even when just one of the two techniques demonstrated their involvement. Radiotherapy doses and volumes varied according to these findings (45 Gy to pelvis as a precautional dose; 6-8 Gy booster dose in N1 cases; 45 Gy to the periaortic area in N4 cases). The two diagnostic techniques agreed as to the presence/absence of pathologic nodes in 50 (64.9%) and 12 (15.6%) patients, respectively. There was disagreement between CT and lymphangiographic findings in 12 patients (15.6%) as regards the pelvic area and in 8 patients as regards the periaortic area (10.4%; 5 of the 8 also figured in the pelvic group). Actuarial 5-year disease-free survival for both groups, summing up stages I, II and III, goes as follows: cervical carcinoma patients: 47% (N0 cases 56%, N1-N4 33%, p = 0.07) and endometrial carcinoma group: 74.5% (no difference was found between N0 and N1 cases). Higher diagnostic accuracy seems to be obtained when CT is combined with lymphangiography than when either of them is performed alone. Therefore, the combined use of the two techniques could have a precise diagnostic role.

Adult↗
PubMed1990

Red blood cell loading with hexokinase and hexokinase-inactivating antibodies. A new strategy for studying the role of enzymes in red cell metabolism and removal.

Human erythrocytes were loaded with homogeneous hexokinase purified from human placenta or with inactivating anti hexokinase IgG, using a procedure of encapsulation based on hypotonic hemolysis, isotonic resealing and reannealing. As a result of these procedures we were able to obtain human erythrocytes with hexokinase levels up to 15-times higher than controls and red blood cells (RBC) with only 10-20% of normal hexokinase activity. RBC with increased hexokinase activity were able to metabolize 1.8-time more glucose than controls, while anti-hexokinase loaded RBC have glycolytic abilities that are only 30% of controls. In both cases the amount of glucose metabolized in the hexose monophosphate pathway was unmodified under resting conditions, but strongly dependent on hexokinase levels in the presence of an oxidative stress. RBC overloaded with hexokinase have a steady-state concentration of glycolytic intermediates that is higher than controls, while 2, 3-diphosphoglycerate and adenine nucleotide levels were almost unchanged. In contrast, RBC with reduced hexokinase activity have a reduced 2, 3-diphosphoglycerate concentration and are not able to maintain their ATP concentration. Inactivation of endogenous RBC hexokinase promotes autologous IgG binding on the RBC membrane. Since the phenomenon is known to be associated with red cell phagocytosis, it could be speculated that in hexokinase deficiency red blood cells are mainly removed by phagocytosis. These results are consistent with suggestions by several investigators that glucose metabolism in human erythrocytes is regulated by hexokinase.

Antibodies↗
PubMed1989

Human red blood cells as bioreactors for the release of 2',3'-dideoxycytidine, an inhibitor of HIV infectivity.

2',3'-Dideoxycytidine (ddCyd) is one of the most potent antiviral nucleosides for killing the human immunodeficiency virus (HIV). ddCyd is currently used in the treatment of severe HIV infections but due to its rapid clearance it must be administered to patients every 4 h reaching concentrations that are toxic. We have synthesized 2',3'-dideoxycytidine-5'-phosphate (ddCMP) as a prodrug, encapsulated it in human erythrocytes and found that it is dephosphorylated by endogenous pyrimidine nucleotidases and subsequently released by the cells as ddCyd. Encapsulated ddCMP does not affect erythrocyte metabolism and was not deaminated by cytidine deaminase. The dephosphorylation reaction has an apparent Km of 6mM, an optimum pH of 6.8 and is not inhibited by ATP or 2,3-bisphosphoglycerate. The efflux of ddCyd from the erythrocyte is a linear function of ddCyd concentration and relatively insensitive to nucleoside transporter inhibitors suggesting that ddCyd permeates the erythrocyte membrane predominantly by nonfacilitated diffusion. Thus, ddCMP-loaded erythrocytes might be used as endogenous bioreactors for ddCyd delivery in the treatment of HIV infection.

Drug Administration Routes↗
PubMed1989

High dose dipyridamole echocardiography early after uncomplicated acute myocardial infarction: correlation with exercise testing and coronary angiography.

The feasibility, safety and usefulness of dipyridamole echocardiography (two-dimensional echocardiography and 12 lead electrocardiographic monitoring during dipyridamole infusion, up to 0.84 mg/kg over 10 min) were evaluated in 94 asymptomatic patients 8 to 10 days after uncomplicated acute myocardial infarction. The results were compared with those of symptom-limited treadmill exercise testing and correlated with coronary angiography. Two mechanical patterns of positivity of dipyridamole echocardiography could be identified: 1) a new wall motion abnormality confined to the infarct zone or to the adjacent segments (24 patients), and 2) transient remote asynergy (33 patients). The success rate in recording adequate images during dipyridamole infusion was 100%. Interobserver agreement concerning diagnosis occurred in 89 (93%) of 94 patients. Dipyridamole echocardiography was well tolerated; no complication was observed during or after the test. Seventy-three patients underwent coronary angiography within 6 weeks after acute myocardial infarction. Transient remote asynergy on echocardiography was present in 27 of 40 patients with multivessel disease and in none of 33 patients without multivessel disease. Results of treadmill exercise testing were positive in 28 patients with multivessel disease and 8 patients without multivessel disease. Thus, the sensitivity of dipyridamole-induced transient remote asynergy was 68% compared with 52% for treadmill testing (p less than 0.05); specificity was 100% and 72%, respectively (p less than 0.005). The overall accuracy of dipyridamole echocardiography (81%) was higher than that of dipyridamole stress electrocardiography (63%) or exercise electrocardiography (60%) (p less than 0.02). It is concluded that dipyridamole echocardiography is a useful, feasible and inexpensive nonexercise-dependent test for detecting the extent of coronary artery disease early after acute myocardial infarction.

Adult↗
PubMed1989

Tuberculosis epidemic among hospital personnel.

Six employees of the emergency department at Parkland Memorial Hospital developed active tuberculosis in 1983-1984. Five of the cases occurred four to 12 months after exposure to the index case, a patient with severe cavitary tuberculosis seen in the emergency department in April 1983. One resident physician developed cavitary disease after exposure to this patient. An additional employee case may have resulted from transmission from one of the initial employee cases. One immunocompromised patient may have acquired tuberculosis as a result of exposure to the index case. In addition, the tuberculin skin tests of at least 47 employees exposed to the index case converted from negative to positive. Of 112 previously tuberculin-negative emergency department employees who were tested in October 1983, 16 developed positive skin tests, including the 5 employees with active disease. Fifteen of these new positives had worked on April 7, 1983, while the index case was in the emergency department (X2 = 20.6, P less than 0.001). Factors related to the genesis of the epidemic included the disease characteristics in the index case and the recirculation of air in the emergency department. This investigation indicates that city-county hospital emergency department employees should be screened at least twice a year for evidence of tuberculosis and that the employee health services of such hospitals should regard the surveillance of tuberculosis infection among personnel at a high-priority level.

Aged↗
PubMed1989

Human red blood cell loading with hexokinase-inactivating antibodies. An in vitro model for enzyme deficiencies.

The primary cause of red cell destruction in enzymopathies of anaerobic remains controversial and difficult to investigate especially because the erythrocyte population in enzymopenic patients is largely heterogeneous. We have shown that loading human erythrocytes with monospecific enzyme-inactivating antibodies could be useful in understanding the biochemical modifications occurring in enzymopenic erythrocytes and the mechanisms leading to red cell destruction. Hexokinase-inactivating antibodies were prepared and loaded in human erythrocytes using a procedure of encapsulation based on hypotonic hemolysis, isotonic resealing and reannealing. Red blood cells loaded with anti-hexokinase IgG showed 20 +/- 3% residual hexokinase activity while all other enzymes were normal. Lactate production by these cells was 30% of controls while the amount of glucose metabolized in the hexose monophosphate pathway (HMP) was unchanged under resting conditions. However, in the presence of methylene blue HMP rates were only 12% of controls. Determination of adenine nucleotide levels suggests that the antihexokinase-loaded red blood cells are not able to maintain, in vitro, their ATP level as well as their 2,3-diphosphoglycerate. Osmotic fragility, methemoglobin, and reduced glutathione content were near normal. These and other properties of the antihexokinase-loaded erythrocytes were similar to those found in cases of hexokinase deficiency. When the antibody-loaded erythrocytes were chromatrographed on immobilized Protein A columns 66-70% of cells were retained by the column against 0-10% of controls suggesting that hexokinase inactivation promotes autologous IgG binding. Since the phenomenon is known to be associated with red cell phagocytosis, it could be concluded that in hexokinase deficiency red cells are mainly removed by phagocytosis, and that hemolysis probably occurs in cases of oxidative stress when the production of a large amount of reducing equivalents (NADPH) is needed but not provided by the hexokinase-deficient erythrocytes.

Animals↗
PubMed1989

[Congenital atrioventricular block and maternal lupus erythematosus. Histologic discovery of tumor of the atrioventricular node].

A case of congenital atrioventricular block in a newborn whose mother presented with systemic lupus erythematosus (SLE) is reported. Despite intensive care the child died a few hours after birth. Serial sections of the heart could be examined. Histology provided information on the appearance and distribution of the lesions. In particular, the sinus node was small for the child's age, and its supplying artery was found to have a hyperplastic media with adventitial sclerosis; the interatrial and interventricular septa showed subendocardial fibrosis invading the adjacent myocardium. Owing to the scarcity of systematic histopathological examinations, such lesions have seldom been described. In addition, a tumour of the atrioventricular node, known as mesothelioma or hemolymphangioma, was discovered. This case is exceptional in that histopathological findings similar to those described in SLE, though rarely as numerous, were associated with a very rare tumour never hitherto described in such a young patient. The relationship between the two categories of lesions is discussed.

Adult↗
PubMed1989

[Correlation between coronary angiographic and ergometric studies after coronary angioplasty].

In 35 patients with effort angina exercise tests before and after coronary angioplasty (PTCA) were compared, aimed at evaluating functional improvement and at correlating some ergometric parameters with angiographic results. All tests were performed during therapy with verapamil 360 mg/die. After PTCA mean diameter of the stenosis was reduced from 68 +/- 11% to 19 +/- 12%. Duration of exercise and rate-pressure product (RPP) were significantly greater in the test after PTCA. While all tests before PTCA were positive, after PTCA ST segment depression occurred in 9 patients (26%). In 7 of these patients it was less than 1 mm. In 26 patients (74%) tests were negative after PTCA. In patients with ST segment depression, ischemia threshold significantly rose from 5.2 +/- 1.5 min (RPP 15,875 +/- 3,253 to 7.6 +/- 1.2 min (RPP 20,157 +/- 3143). Maximal ST segment depression and ST/HR slope were significantly reduced. In negative stress tests the time free from ischemia significantly rose from 6.5 +/- 2.6 min (RPP 18,872 +/- 3,861) to 10.5 +/- 2.3 min (RPP 28,476 +/- 4,289). In patients with positive tests stenosis after PTCA was more severe than in patients without ST segment depression (29 +/- 13% vs 17 +/- 13%). In patients with ST segment depression improvement of ischemia threshold and of stenosis were correlated. In these patients improvement of ischemia threshold is the ergometric parameter more useful to evaluate the angiographic result of PTCA.

Adult↗
PubMed1989

Acutely transforming retroviruses as carcinogens in mouse embryos.

Spontaneous and induced transmission of oncogenic retroviruses from parents to offspring is well documented in mammals, as exemplified by murine leukaemia viruses. In addition, it is now common knowledge that transgenic mice, carrying viral and cellular transforming genes, can show unusual tumour incidences and can transmit this character to successive generations. The present report deals with the occurrence of tumours in rodents exposed directly in utero to murine sarcoma viruses (MSV). Attention was focused on whether MSV are involved in the etiopathogenetic processes leading to early-life and adult-type neoplasms in mice. According to our data, this is a likely possibility, since, for example, Kirsten MSV (Ki-MSV) induced stage-specific tumours in CD-1 mice, including lung tumours and skin papillomas, following intraembryonal injections on gestation days 8 and 10, respectively. When the injections were given in the second half of pregnancy, however, only capillary angiomas and other vascular malformations of the brain, as well as mesenchymal sarcomas, were induced in the newborn. Harvey MSV (Ha-MSV), a close relative of Ki-MSV, and Moloney MSV (Mo-MSV) were much less dependent on the stage of embryogenesis, and mesenchymal sarcomas were frequently detected in prenatally infected animals. Other MSV viruses, including 3611, J-2 and 4070A, were active carcinogens in a way totally independent of the embryonal stage exposed, and tumours in the progeny ranged from mesenchymal sarcomas to lymphoblastomas and rhabdomyosarcomas, respectively. We next looked at the possibility that spontaneous tumours of CD-1 mice might result from the interaction of certain chemical carcinogens with developmentally expressed components of the Ki-MSV virus. The experiments conducted thus far have provided dubious results. An example is given by experiments with N-ethyl-N-nitrosourea (ENU). This compound is a powerful transplacental carcinogen in CD-1 mice, where it induces lung tumours. It was expected that by exposing developing mice to Ki-MSV on day 8 of embryogenesis and to ENU late in pregnancy or in newborns, a great increase in the incidence of lung tumours would have appeared in the offspring. However, this did not happen, and the agents behaved as if different cellular targets were involved. Understanding this difference could be very informative and useful in identifying neoplastic factors in mammalian embryos.

Animals↗
PubMed1989

2',3'-dideoxycytidine permeation of the human erythrocyte membrane.

The mechanism by which 2,3'-dideoxycytidine, an inhibitor of HIV-I infectivity, permeates the cell membrane was investigated. The influx of ddCyd into human erythrocytes was nonconcentrative. The initial velocity of both ddCyd influx and efflux was, in contrast to compounds that permeate the cell membrane via the nucleoside transporter, a linear function of nucleoside concentration in the 1 microM to 10 mM range and relatively insensitive to temperature. Furthermore, potent inhibitors of nucleoside transporter and other nucleosides were found to inhibit ddCyd influx only partially or not at all suggesting that ddCyd permeates the human erythrocyte membrane predominantly by nonfacilitated diffusion. This unusual characteristic seems to be due to the lack of 3'-hydroxyl moiety of ddCyd which appears to be an important determinant for the nucleoside carrier specificity rather than to lipid solubility itself. As far as permeation of the cell membrane is concerned ddCyd shares these properties with 2',3'-dideoxythymidine and 3'-azido-3'-deoxythymidine.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Long-term prognostic value of serum bile acids in liver cirrhosis: a prospective study.

The long-term prognostic significance of serum bile acid (SBA) levels in liver cirrhosis was prospectively evaluated in a 3-year follow-up of 111 patients. The predictive value of SBA levels, of Child classification, and of some commonly used clinical and laboratory parameters were compared analyzing the survivorship functions by means of Life-table method and chi-square Logrank test. SBA determinations showed a high prognostic significance, comparable with the one of the multiparameteric Child classification and significantly higher than the ones of any considered single clinical or laboratory parameter. SBA levels by themselves seem therefore to be of some value in establishing an approximate survivorship prediction in liver cirrhosis, thus representing a possible alternative to multiparametric predictive models in routinary clinical practice.

Adult↗