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Biomedical subjects

A Fabbri

Publications and source records attributed to A Fabbri.

At least 127 records · Page 7Linked to original sources
PubMed1996

Laser Doppler flowmeter assessment of skin microcirculation in uremic patients on hemodialysis treatment.

Vascular disease is frequent in uremics and may contribute to tissue malnutrition and damage. The aim of this study was to detect whether uremic patients show also changes of microcirculation and to evaluate the effects induced by hemodialysis (HD) session. Eleven uremics on HD (7 males, 4 females, aged 25-65 years) were studied; 11 healthy subjects, age- and sex-matched, served as controls. Skin microcirculatory basal flow (BF), maximal postischemic flow (PIF-max) and flow motion index (FMI) were determined at the upper limb contralateral to arteriovenous fistula, by means of a laser Doppler flowmeter. The measurements were taken before, at 1 and 2 h after starting HD and 30 min after the end of HD. In uremics, FMI was lower than in controls (mean +/- SD: 15.2 +/- 13.6 vs. 29.1 +/- 7.4%; p < 0.005); just 1 h after the start of HD, a significant improvement (28.4 +/- 17.7%; p < 0.01) versus basal values was observed and it persisted throughout the HD session. No statistical correlation was observed between the changes of FMI and those of plasma levels of Na+, K+, HCO-3, urea, iPTH or rate of ultrafiltration. BF and PIF-max were similar in uremics and controls, and no changes were observed during HD. Our study shows that the physiological flow motion is reduced in the skin microcirculation of uremics on HD. This abnormality is rapidly corrected by HD.

Adult↗
PubMed1996

The galactose elimination capacity test: a study of the technique based on the analysis of 868 measurements.

OBJECTIVES: Our objective in this study was to analyze the correspondence of galactose concentration-on-time-decay curve to theoretical assumptions and the confidence limits of the determination of galactose elimination capacity. METHODS: We analyzed a retrospective series of 868 galactose elimination tests, performed on subjects with and without liver disease. Zero-order kinetics of galactose elimination was tested by comparison of the residual variance of linear regression with that obtained after quadratic transformation. The uncertainty in determination of galactose elimination capacity was calculated on the regression line by computing the 95% confidence limits of the estimate. RESULTS: The time-course of galactose concentration suggested an initial uneven distribution, and the first (20-min) data point deviated significantly from the regression. The galactose decay curve in plasma rejected linearity in 13% of tests; after exclusion of the first data-point, linearity was rejected in only 3% of cases. The 95% confidence interval of galactose elimination capacity was on average +/- 16%, but in individual tests it was as large as +/- 60-80%. The uncertainty of the test was not affected by linearity. It was larger, with poor fitting of the experimental data on the regression of galactose concentration on time, low number of data points, and low galactose elimination. It was maintained within +/- 20% only when residual variance was > or = 2% of total variance (nearly 50% of tests). CONCLUSION: The methodology for the determination of galactose elimination capacity leads to considerable uncertainty as to the final result, which must be considered whenever the test is used for clinical purposes in the decision-making process. It tends to be larger in patients with advanced disease and can be accurately calculated so as to contribute to a proper evaluation of the test result.

Adolescent↗
PubMed1996

[Azoospermia and genetic mutations: implications for the methods of in vitro fertilization].

Much evidence suggests the fundamental role of the Y chromosome during spermatogenesis. Especially, a gene on the long arm (localized in a portion of the chromosome called Yq11), the AZF (azoospermic factor), is necessary for the achievement and the maintenance of the spermatogenetic process. In fact mutations and deletions in this part of the chromosome inevitably cause severe oligozoospermia or azoospermia. Furthermore other genes on the short arm seem to have a role during spermatogenesis: they are called ZFY (zink finger Y, which encodes a DNA binding protein) and TSPY (expressed in the spermatids nuclei); but the function of these genes is still uncertain, since at this moment no deletions or mutations have been found at this level. Further genes only recently cloned include the CREM (cAMP-responsive element modulator), whose mutation causes azoospermia with a spermatidic arrest in the mouse, and the complex c-kit/Steel-factor. The latter is essential for spermatogonial proliferation and differentiation, so that an alteration at this level can determine spermatogonial arrest or the absence of germinal cells with the presence of Sertoli cells only (Sertoli cells only syndrome). In contrast with AZF, both the CREM gene and c-kit/Steel-factor genes are autosomal (chromosome 10 for the CREM, 4 for c-kit, 1 for Steel-factor, respectively). Several genes may be involved in the spermatogenetic process, but their role, excepting for AZF, is still unclear.

Animals↗
PubMed1995

Thyroid volume in type 1 diabetes patients without overt thyroid disease.

An association between insulin-dependent diabetes mellitus (type 1) and thyroid diseases has long been reported, but the morphological evaluation of the thyroid in type 1 diabetes patients without overt thyroid disease has always been limited to physical examination. Ultrasonography of the thyroid gland was performed in 45 patients with type 1 diabetes without overt thyroid disease, to study thyroid volume and the prevalence of thyroid nodules. Data were compared with those obtained in 45 age- and sex-matched control subjects residing in the same area. In the patients, thyroid volume had increased on average by 46%; 35% of male and 32% of female patients had a thyroid volume exceeding the 95% confidence limits of the matched controls. The prevalence of thyroid nodules was only slightly raised. On average, free thyroxine was increased in the presence of normal triiodothyronine levels. Four patients were frankly hyperthyroid. The patients also showed a higher prevalence of thyroid-microsomal antibodies, but the thyroid hormone status was not different in relation to thyroid volume, nor was thyroid volume in relation to the presence of autoantibodies. Patients with type 1 diabetes without overt thyroid disorders may have morphological, ultrasonographically detectable alterations of the thyroid gland, the expression of a possible involvement of the thyroid in an autoimmune disorder not limited to the islet cells.

Adolescent↗
PubMed1995

Effects of beta-blockade on hepatic conversion of amino acid nitrogen and on urea synthesis in cirrhosis.

beta-Blockers are widely used to prevent gastrointestinal hemorrhage in cirrhosis. The metabolic effects of treatment are scarcely studied: hepatic function reportedly does not change significantly, but beta-adrenoceptors have been reported to regulate protein and amino acid metabolism. We studied hepatic nitrogen metabolism in response to constant alanine infusion in seven patients with cirrhosis before and 7 to 10 days after treatment with oral propranolol (60 to 100 mg/d). Beta-blockade was effective: it decreased heart rate by 25%, abolished orthostatic tachycardia, and reduced portal blood flow by 20%. Alanine-stimulated urea nitrogen synthesis rate (UNSR) was higher in patients with propranolol treatment, without any difference in aminonitrogen concentration. The kinetics of hepatic conversion of amino acid nitrogen into urea--ie, functional hepatic nitrogen clearance (FHNC)--increased by 30%, from (mean +/- SD) 17.0 +/- 4.1 to 22.0 +/- 6.6 L/h (P < .01). Increased urea production during alanine infusion resulted in negative nitrogen exchange even at the peak of alpha-aminonitrogen concentration. Basal insulin level was only slightly reduced during propranolol treatment, whereas the insulin response to alanine was significantly blunted. No differences in glucagon and cortisol were demonstrated. Epinephrine and norepinephrine levels were high-normal and did not vary after treatment. Increased urea production and stimulation of hepatic nitrogen clearance during beta-blockade may be mediated by relative hypoinsulinemia or by direct involvement of beta-adrenoceptors in the control of nitrogen metabolism, possibly by regulation of amino acid uptake and release in peripheral tissues.

Aged↗
PubMed1995

Stentless porcine bioprostheses in the treatment of aortic valve infective endocarditis.

Between January 1992 and June 1994, 23 patients underwent surgery for aortic valve endocarditis at the Department of Cardiovascular Surgery of the University of Verona; a subgroup of 10 patients underwent aortic valve replacement with a porcine stentless valve (Biocor LTDA n = 8; Toronto SPV n = 2). There were 7 males and 3 females with a mean age of 56.3 years (range, 36 to 73 years). Eight patients had active endocarditis and two had healed endocarditis. Nine patients had native valve in endocarditis, the presence of a bicuspid aortic valve in 2, and 1 patient had recurrent prosthetic valve endocarditis (PVE), 7 of whom were in New York Heart Association (NYHA) Functional Class IV. The main indications for operation were congestive cardiac failure, active sepsis, and presence of large and mobile vegetations by echo and arrhythmias. There were no operative or late mortalities in this subgroup of patients. Short-term survival is 100% at a mean follow-up time of 11.2 months (range, 4 to 18 months), with no recurrent endocarditis or valve-related complications.

Adult↗
PubMed1995

Myocardial revascularization using branches of the left internal mammary artery.

To increase the number of arterial grafts in patients with multivessel coronary disease, we have used branches of the left internal mammary artery (LIMA) as bypass grafts. From March 1990 to June 1993, 15 patients (13 males and 2 females) aged 38 to 65 years (mean 57 +/- 8), received a total of 30 LIMA branch anastomoses. The two terminal branches were used to perform a "Y" graft to the left anterior descending coronary artery territory in 13 patients. A pericardiophrenic branch was used in four cases. Five patients (33.3%) had complete myocardial revascularization using IMA only. There were neither early nor late deaths and all patients are free from angina at a mean follow-up of 20 months (6 to 45 months). However, early postoperative cardiac catheterization, performed in 12 patients (80%), revealed a 20% occlusion rate for each terminal branch and a 50% occlusion rate for the pericardiophrenic branch. Technically challenging due to the small diameter of the grafts, the terminal LIMA branches should be limited to selected patients when more conventional arterial or vein conduits are not available. More proximal branches have a higher occlusion rate and their use is not recommended.

Adult↗
PubMed1995

Escherichia coli cytotoxic necrotizing factor 1: evidence for induction of actin assembly by constitutive activation of the p21 Rho GTPase.

Cytotoxic necrotizing factor type 1 (CNF1) induces in HEp-2 cells an increase in F-actin structures, which was detectable by fluorescence-activated cell sorter analysis 24 h after addition of this factor to the culture medium. Increase in F-actin was correlated with the augmentation of both the cell volume and the total cell actin content. Actin assembly-disassembly is controlled by small GTP-binding proteins of the Rho family, which have been reported recently to be modified by CNF1 treatment. Clostridium difficile toxin B and Clostridium botulinum exoenzyme C3, both known to act on the Rho GTPase, were used as biological tools to study the effect of CNF1 on this protein. CNF1 incubated before, during, or after exposure to the chimeric toxin C3B (which is the product of a genetic fusion between the DNA coding for C3 and the one coding for the B fragment of diphtheria toxin) protected HEp-2 cells from the disruption of F-actin structures caused by inactivation of the Rho GTPase through its ADP-ribosylation. On the other hand, C. difficile toxin B cytopathic effect was not observed upon preincubation of cells with CNF1. Toxins acting through a Rho-independent mechanism, such as cytochalasin D and Clostridium spiroforme iota-like toxin, could not be modified in their cellular activities by CNF1 treatment. All of our results suggest that CNF1 modifies the Rho molecule, thus probably protecting this GTPase from further bacterial toxin modification.

ADP Ribose Transferases↗
PubMed1995

Growth hormone-releasing hormone in testicular interstitial and germ cells: potential paracrine modulation of follicle-stimulating hormone action on Sertoli cell function.

GH-releasing hormone (GHRH) is present in the interstitial and germ cells of the rat testis. In previous studies we found that GHRH is secreted from rat adult Leydig cells, in which it stimulates basal and LH-induced cAMP formation and steroidogenesis. In other studies cAMP production in Sertoli cells was found to be stimulated by GHRH. In the present report, we describe a potential paracrine action of GHRH in the Sertoli cell, with stimulation of cAMP formation in cultured adult and pubertal Sertoli cells. GHRH increased FSH-stimulated cAMP production in adult and pubertal cultures in a time-dependent manner. GHRH stimulation of basal and FSH-induced extracellular cAMP formation was more prominent in pubertal than in adult cultures. Immunocytochemical studies demonstrated the presence of GHRH-like immunoreactivity in rat interstitial cells from day 4 to adult life and in the acrosomal region of early and intermediate spermatids at stages III-VI of the seminiferous epithelium cycle. Immunoreactive GHRH was not observed in late spermatids and mature sperm or in Sertoli cells at any age. These results indicate that GHRH acts synergistically with FSH to promote cAMP production in Sertoli cells in culture. Testicular GHRH of Leydig and germ cell origin may be an important paracrine regulator of Sertoli cell function. Alternatively, GHRH present in germ cells may exert stage-specific intracrine functions.

Aging↗
PubMed1995

Preliminary experience with pulmonary autografts.

Between July 1994 and March 1995, seven patients (six male) with a mean age of 27 years (range 18 to 34 years) were selected for aortic valve replacement with a pulmonary autograft (Ross operation). The aortic valve disease was isolated insufficiency in four cases, stenosis in one and mixed lesion in two. Three patients had a bicuspid aortic valve. Previous cardiac surgical procedures had been performed in two cases (coarctation repair and valvuloplasty in one; isolated aortic valvuloplasty in one). Two patients were in NYHA class II and five in class III. In two cases the autograft was inserted as a scalloped subcoronary implant. Four patients had total aortic root replacement with re-implantation of the coronary ostia. The RVOT was reconstructed with a cryopreserved homograft (five pulmonary two aortic). The aortic cross-clamp time was 150 +/- 10 minutes with a total bypass time of 212 +/- 14 minutes. There was neither operative nor late mortality. Postoperative echocardiography revealed trivial autograft insufficiency in one case with a mean transvalvular gradient of 15.8 mmHg. All patients improved symptomatically (100% in NYHA class I). Freedom from reoperation, valve related complications and endocarditis is 100% at a mean follow up of 5.6 months (range 1-9 months). This preliminary experience supports the concept of pulmonary autograft implantation in selected patients.

Adolescent↗
PubMed1994

Hepatic conversion of amino-nitrogen to urea in thyroid diseases. II. A study in hyperthyroid patients.

Conflicting data have been reported on the influence of thyroid hormones on hepatic nitrogen metabolism and on liver metabolic activity. We studied the urea-nitrogen synthesis rate (UNSR) and the kinetics of the process of hepatic amino-nitrogen to urea-nitrogen conversion in response to constant alanine infusion (ie, the functional hepatic nitrogen clearance [FHNC]) in five hyperthyroid female patients before and after the achievement of a stable euthyroid status. In the same patients, galactose elimination capacity and antipyrine clearance were also measured as quantitative indices of hepatic function. The basal urea synthesis rate was nearly doubled in hyperthyroid patients (35.6 +/- 8.5 mmol.h-1 v 17.6 +/- 7.7 in euthyroid patients, P < .05) and increased linearly with increasing alpha-amino-nitrogen (alpha-AN) concentrations in both conditions. The urea synthesis rate during alanine infusion was still higher by approximately 30 mmol.h-1 in hyperthyroid subjects. The FHNC, calculated as the slope of the linear relation between the UNSR in each time interval and the corresponding average alpha-AN concentration, was not different (hyperthyroidism, 30.6 +/- 7.2 L.h-1; euthyroidism, 28.5 +/- 4.4; normal values > 25). The hepatic microsomal and cytosolic activities (antipyrine clearance and galactose elimination) were normal in hyperthyroid patients and did not change significantly after therapy. Our data show that the hepatic nitrogen metabolism of hyperthyroid patients is characterized by an upregulation of amino-nitrogen catabolism and loss of the sparing mechanism at low plasma amino acid levels, without any change in different metabolic activities.

Adult↗
PubMed1994

Indications of reduced pulmonary function in type 1 (insulin-dependent) diabetes mellitus.

Abnormalities of pulmonary function tests have been described in type 1 (insulin-dependent) diabetes mellitus (IDDM). To better characterise such abnormalities and to verify whether these latter are associated with the presence of diabetic microvascular disease we compared 23 non-smoking patients who had IDDM with 24 non-smoking healthy control subjects strictly matched for sex, age, and body mass index. Compared with controls, diabetic patients had a reduced forced vital capacity (FVC) (87.5 +/- 13.1% vs. 96.4 +/- 13.6% of the predicted; P = 0.03) and forced expiratory volume in 1 s (FEV1) (90.5 +/- 17.7% vs. 101.2 +/- 13.2% of the predicted; P = 0.02). While within the group of patients the presence of retinopathy and autonomic neuropathy were not associated with modifications of pulmonary function tests, those with altered urinary albumin excretion rate (AER > or = 20 micrograms/min; range 21-589) (n = 7) had a significantly lower pulmonary diffusion capacity (DLCO) than the 16 normoalbuminuric subjects (62.6 +/- 7.2% vs. 88.7 +/- 20.1% of the predicted; P = 0.01). Moreover, in the group of patients, DLCO was inversely related with AER (r = -0.43; P = 0.04). In conclusion, IDDM is characterised by reduced FVC and FEV1, while a significant decrease in DLCO may be considered as selectively associated with renal disease.

Adult↗
PubMed1994

Prognostic significance of diabetes in patients with cirrhosis.

Alterations in carbohydrate metabolism are frequently observed in cirrhosis, and approximately 15% to 30% of patients have overt diabetes. In a retrospective and prospective study in cirrhosis, we analyzed the prognostic significance of diabetes, which was defined as the presence of hyperglycemia and overt glycosuria that in most cases required dietary restrictions or active treatment. The clinical records of all patients with cirrhosis admitted to our department for the period 1980 to 1985 were reviewed in 1985 and 1986, and surviving patients were prospectively followed up until December 1991. Final status could be obtained in 354 (98 with diabetes) of 382 eligible patients; 110 were alive at the end of follow-up. Prognostic factors were identified by Kaplan-Meier analysis, followed by Cox's stepwise regression. The model identified, in sequence, albumin, ascites, age, encephalopathy, bilirubin, diabetes, and platelets as prognostic factors. The larger mortality rate in patients with diabetes was not due to complications of diabetes but to an increased risk of hepatocellular failure. Diabetes was no longer a risk factor as a covariate in a subgroup of 271 patients when varices were added but was again significant when patients who died of gastrointestinal bleeding were excluded. The presence of diabetes, clinically detectable and often requiring adequate treatment, is a risk factor for long-term survival in cirrhosis.

Adolescent↗
PubMed1994

Analgesic-antiinflammatory drugs inhibit orbicularis oculi reflexes in humans via a central mode of action.

1. A cross-over single blind study examined the possible central effects of non-opioid analgesic drugs on the trigeminal reflexes. 2. The corneal reflex and blink reflex (R1, R2) were recorded electromyographically and response areas measured in healthy volunteers before and after intramuscular injection of piroxicam (40 mg); and after intravenous injection of lysine acetylsalicylate (500 mg). After the last drug recording the subjects received intravenous naloxone (2 mg) followed 5 minutes later by further reflex testing. Saline was used as a placebo in control experiments. 3. Both analgesics reduced the corneal reflex: piroxicam induced a 27% and lysine acetylsalicylate a 21% a reduction that naloxone did not reverse. Neither drug reduced the early or the late component of the blink reflex. 4. The marked inhibitory changes that the two non-narcotic analgesics produced on the corneal reflex--a nociceptive response--indicate a centrally-mediated action. 5. Naloxone's failure to reverse the induced analgesia argues against opiate receptor mediation.

Adult↗
PubMed1994

High-dose methotrexate treatment and liver function in patients with osteosarcoma.

OBJECTIVES: To study the effects of short-term high-dose methotrexate therapy on liver function in patients with osteosarcoma. DESIGN: Open prospective study. SETTING: Department of Internal Medicine and Oncology, Istituto Ortopedico Rizzoli, Bologna, Italy. SUBJECTS: Fourteen patients with osteosarcoma, with no evidence of previous or actual liver disease at the time of diagnosis. INTERVENTIONS: All patients received a cumulative dose of 30-57 gm-2 of methotrexate within 6 months as neo-adjuvant chemotherapy (pre- and post-surgery). Each course of chemotherapy included methotrexate at a dose of 8-12 gm-2 and, in addition, adriamycin and cisplatinum. MAIN OUTCOME MEASURES: Galactose elimination capacity and antipyrine clearance were measured at baseline, after the first course of chemotherapy, at the end of the pre-operative period and at the end of chemotherapy. In each case they were carried out after transaminase levels had returned to normal. RESULTS: Galactose elimination capacity decreased from 2.45 (+/- 0.48) mM min-1 to 2.04 (+/- 0.60) mM min-1 after the five planned courses of chemotherapy (P = 0.013, Wilcoxon signed-rank test), without any change in routine liver function tests. No differences in antipyrine clearance and half-life were demonstrated (n = 8). CONCLUSIONS: The data are consistent with a decreased reserve capacity of the liver after short-term, high-dose methotrexate. Long-term survivors deserve monitoring of liver function for safer methotrexate use, in the light of progressive dosage increments to improve prognosis in neoplastic diseases.

Adolescent↗