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Biomedical subjects

V Esposito

Publications and source records attributed to V Esposito.

At least 91 records · Page 5Linked to original sources
PubMed1996

The valva portalis renalis in the duck (Anas platyrhynchos).

The morphology of the valva portalis renalis of the duck was investigated, using histological, SEM and TEM techniques. The wall thickness of the vena iliaca externa, the vena portalis renalis caudalis, the vena iliaca communis and the vena renalis caudalis was morphometrically evaluated. The blood pressure in these veins was measured using a three-way H2O manometer. The valva portalis renalis was composed primarily of epithelioid cells and lined with endothelium. Throughout the entire valva there was a dense complex of nerve structures made up of fibers and fiber bundles which also extended beneath the endothelium of the valva and around the subendothelial epithelioid cells. The wall thicknesses of the veins supplying the renal portal system (vena iliaca externa and vena portalis renalis caudalis) were greater than those of the vessels collecting the renal refluent venous blood (vena iliaca communis and vena renalis caudalis). In addition, the blood pressure values taken in the vena iliaca externa and the vena portalis renalis caudalis were much higher than those in the vena iliaca communis and the vena renalis caudalis. The above observations suggest that the renal portal system works at higher blood pressure levels than the general venous system and that the valva portalis renalis regulates its aperture in order to maintain a constant blood pressure and a continuous blood flow in the renal portal system vessels, hence avoiding damage to the renal parenchyma caused by pressure overloads.

Animals↗
PubMed1996

Differential expression of the retinoblastoma gene family members pRb/p105, p107, and pRb2/p130 in lung cancer.

The Rb (retinoblastoma) gene family is composed of three members: the RB gene (one of the best-studied tumor suppressor genes) and two related genes, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Using immunocytochemical techniques, we evaluated a variety of lung tumor specimens for the expression of this family of proteins and compared protein expression with the histological grading of the tumors and with the expression of the proliferating cell nuclear antigen. These Rb family members displayed distinctive patterns when compared and contrasted using different parameters. The highest percentage of undetectable levels in all of the specimens examined and the tightest inverse correlation (P) with the histological grading and with proliferating cell nuclear antigen expression in the most aggressive tumor types were found for pRb2/p130, which may suggest an important role for this protein in the pathogenesis and progression of lung cancer.

Animals↗
PubMed1995

Administration of a nitric oxide synthase inhibitor does not suppress low-dose streptozotocin-induced diabetes in mice.

Nitric oxide (NO) has been reported as being a key mediator of the autoimmune destruction of B-cells in type I diabetes, and studies have described a suppression of low-dose streptozotocin-induced (LDS) diabetes in mice after the use of NO synthase inhibitors. However, these studies disagree with regard to the outcome of hyperglycemia and insulitis after treatment with these L-arginine analogs. The present study tries to clarify this topic by administering N-nitro-L-arginine-methylester (NAME) (15 mg/d/mouse/15 d) after an LDS treatment in 108 male C57BL6/J mice. Glycemia measured at the end of the NAME treatment did show a slight, but significant, reduction when compared to LDS control animals (p < 0.001), but values returned to diabetic levels 2 wk after withdrawal of NAME. Morphological observations demonstrated that the degree of infiltration and islet B-cell damage was absolutely not inhibited by NAME. In conclusion, treatment with L-arginine analogs is not capable of protecting mice from LDS-induced diabetes.

Animals↗
PubMed1995

Growth rate and growth hormone response to growth hormone-releasing hormone challenge in slowly growing children during chronic administration of clonidine.

In this study the effects of chronic administration of clonidine, an alpha-2-adrenergic agonist, on the growth rate and GH response to GHRH in 12 "slowly growing" children were reported. Clonidine was administered at the dose of 0.04 mg/m2 body surface twice daily along 12 months. The protocol of the study consisted in five periods of growth rate, insulin-like growth factor-1, basal and GHRH-stimulated GH level evaluation: 1) 6-month pretreatment (P1); 2) 6-month placebo administration (PO); 3) after 4 months of therapy (P1); 4) after 4 months of clonidine withdrawal (P2); 5) after 4 months of therapy reinstatement (P3). No difference was observed between P-1 and P0 when all the parameters were considered. During P1 a significant increase of linear growth (p < 0.05 vs P0 and P-1) was observed while standard deviation of height was not modified. At the end of P2, the growth rate and standard deviation of height were similar to those recorded in P0 and P-1. After reinstatement of clonidine therapy a new but less pronounced rise of the growth rate was found (p < 0.05 vs P1, p < 0.01 vs P0 and P-1). GH, insulin-like growth factor-1, GHRH-stimulated GH levels had significantly increased during P1 than P0 and P-1 (p < 0.05), while during P2 they were similar to P0 and P-1. During P3 a new increase of insulin-like growth factor-I baseline and GHRH-stimulated GH levels were observed. However, these were significantly lower than those observed during P1.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Determination by Skeleton↗
PubMed1995

Effects of gonadal steroids on the growth of human pituitary adenomas in vitro.

The effects of testosterone (T), dihydrotestosterone (DHT) and methyltrienolone (R 1881) on cell proliferation of eight human pituitary tumors in culture wre assessed by [3H]thymidine incorporation and compared to those of progesterone (Pg) and 17 beta-estradiol. Receptors for androgens (AR), estrogens (ER) and progesterone (PgR) were characterized. AR had a significant inhibitory effect on all AR-positive tumors, whatever their hormonal content. Inhibitory effects of either T and DHT < R1881 < Pg were observed in tumors co-expressing AR and PgR. The inhibitory effect of R 1881 on a PgR-positive/AR-negative tumor suggested that R 1881 action was partially PgR-mediated. The effects of either T or the nonaromatizable DHT and R 1881 were unrelated to ER expression. We conclude that AR can modulate the growth of human pituitary tumors through direct receptor-mediated intracellular pathways which may be common to various pituitary cell types.

Adenoma↗
PubMed1995

Acute and chronic effects of human recombinant GH (hrGH) on adrenal steroidogenesis in children affected with isolated GH deficiency (IGHD).

In a previous study we demonstrated that, in children affected with isolated GH deficiency, an acute high-dose human recombinant GH (hrGH) treatment increases the 11-deoxycortisol and induces an IGF-I responsiveness to ACTH. The aim of the present study was to reevaluate, in the same children, the adrenal and IGF-I responsiveness to ACTH after a chronic replacement-dose GH therapy. Ten children (seven males and three females, mean age 7 years) affected with isolated GH deficiency underwent a synthetic ACTH 1-17 test before and after sc administration of human recombinant GH at a dose of 0.6 UI/kg/week for 3 months. After therapy, the 11-deoxycortisol responsiveness to ACTH significantly decreased compared with that observed after acute treatment (P < 0.001), and so it returned to baseline. No differences were detected in the responsiveness to ACTH of cortisol, dehydroepiandrosterone-sulphate, D4-androstenedione, and 17-hydroxyprogesterone. On the other hand, the chronic treatment induced an IGF-I responsiveness to ACTH (P < 0.001). In conclusion, our study demonstrates that, in isolated GH deficiency, replacement doses of hrGH do not modify the adrenal steroid basal levels or its responsiveness to ACTH, whereas both replacement and high doses of hrGH induce an IGF-I responsiveness to ACTH.

17-Ketosteroids↗
PubMed1995

Impairment of lung volumes and respiratory muscle strength in adult patients with growth hormone deficiency.

Little is known of the respiratory function in patients with growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient in childhood. Ten patients diagnosed as GH deficient in childhood and ten healthy subjects entered the study. For each subject the evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, recording of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Both maximal inspiratory and expiratory mouth pressures were decreased in GH deficiency. Vital capacity, N2 functional residual capacity and total lung capacity were significantly reduced when compared to healthy subjects. Conversely, the residual volume and diffusing lung capacity to CO did not show any significant change. No significant change of percentage forced expiratory volume in 1 s/forced vital capacity ratio was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. In conclusion, the results of this study show that adult patients affected with childhood onset GH deficiency suffer from impairment of ventilatory function and a decrease of respiratory muscle pressures, probably due to reduction of respiratory muscle strength.

Adult↗
PubMed1995

Transmaxillosphenoidal approach to tumors invading the medial compartment of the cavernous sinus.

A transmaxillosphenoidal approach was used to remove sellar tumors invading the cavernous sinus. This procedure, a widening of the standard transsphenoidal approach to the sella turcica, uses the sublabial or transnasal route in which the medial wall of the maxillary sinus is laterally dislocated. This method provides good exposure of the prominences of bone above the carotid artery which lies on the posterolateral wall of the sphenoid sinus. This bone area is the key to opening the cavernous sinus inferomedially and removing lesions within its medial compartment. The inferomedial approach takes an entirely extracerebral route so that tumors invading the cavernous sinus through its medial wall are approached inferomedially following the direction of tumor growth. It also allows direct visualization of the intracavernous carotid artery during tumor removal, thus sparing the cranial nerves, which run on the opposite side. Adequate surgical exposure of a pituitary adenoma is achieved with a custom-made sphenoidal retractor with asymmetric blades, the shorter blade holding aside the thin medial wall of the maxillary sinus. Between October, 1989, and July, 1993, 11 patients with tumors invading the cavernous sinus underwent surgery via this approach; 10 had pituitary adenomas and one had a craniopharyngioma. Eight tumors were treated by primary operation: four tumors were totally and four subtotally (> 80%) removed; one tumor already operated on elsewhere was totally removed; and of two tumors already operated on and irradiated, one was subtotally removed and the other only partially (approximately 40%) removed owing to marked postirradiation scarring. None of the patients suffered permanent cranial nerve deficit and all but one showed marked clinical improvement.

Adenoma↗
PubMed1995

[Assessment of dispersion++ of ventricular recovery in patients with chronic obstructive pulmonary disease].

Cardiac arrhythmias are common in patients with chronic obstructive pulmonary disease. Several factors may contribute to the development of arrhythmias in these patients including hypoxemia, hypercapnia, acid-base disturbances. The aim of the study was to assess QTc dispersion in patients with chronic obstructive pulmonary disease, who are at high risk of arrhythmias. Interlead QT variability as measured on the 12-lead electrocardiogram is not a technical artifact but probably reflects regional differences in ventricular repolarization. Increased dispersion of ventricular recovery time is believed to provide a substrate which supports serious ventricular arrhythmias. We showed that in patients with chronic obstructive pulmonary disease, free of underlying structural heart disease, the QTc dispersion is significant greater (p = 0.036) than in a control group, despite a similar value in mean QTc value. The data of the present study suggest that the determination of dispersion of repolarization times may be affected by metabolic changes occurring in patients with chronic obstructive pulmonary disease.

Adult↗
PubMed1994

The supine position for transsphenoidal surgery.

The supine position has been routinely used for transphenoidal microsurgery in our department since 1973. We had 404 patients, 387 of whom had pituitary micro-or macroadenomas. It is always satisfactory, allowing a very good control of intraoperative arterial pressure and prevention of air embolism. It is also comfortable for both surgeons.

Adenoma↗
PubMed1994

Extrahypothalamic distribution of vasoactive intestinal polypeptide (VIP)-like immunoreactivity in the chicken brain, Gallus domesticus.

The distribution of VIP-immunoreactive neurons and fibers was detected in the extrahypothalamic areas of chicken brain by immunohistochemistry and light microscopy VIP-ir perikarya were found in the hippocampus and in the area parahippocampalis; in the area ventralis of Tsai, in the n. interpeduncularis, in the substantia nigra, in the substantia grisea centralis, in the locus coeruleus, in the n. subcoeruleus ventralis and in the n. pontis lateralis. VIP-ir fibers were seen in the lobus parolfactorius and throughout the brainstem mainly arranged in lateral and midsagittal position. This finding was discussed in relation to other studies performed on chicken and/or other avian brain. The distributional pattern of VIP-ergic system in the chicken brain suggests a possible involvement of VIP or VIP-like peptide in several neuroregulatory mechanisms.

Animals↗
PubMed1994

A simple method for stereotactic microsurgical excision of small, deep-seated cavernous angiomas.

Eight patients underwent microsurgical excision of small, deep-seated cavernous angiomas (maximum diameter, 0.9 to 2 cm; distance from cortical surface, 3.5 to 6.5 cm) by the stereotactic implantation of a guide catheter. In all cases, the lesion was quickly localized and completely removed. None of the patients had postoperative neurological deficits. Once the guide catheter has been implanted, the stereotactic headframe can be removed, allowing the unobstructed use of the operating microscope with frames not suitable for open surgery. Target localization is not affected by brain movement, which is inevitable during open surgery. The procedure described here is simple to perform and relatively inexpensive. It requires no specially designed equipment, only a standard stereotactic apparatus, an operating microscope, and the usual microsurgical instruments.

Adult↗
PubMed1994

Predictors of perinatal outcome in intrauterine growth retardation: a long term study.

UNLABELLED: Fifty-three intrauterine retarded fetuses (IUGR) and seventy-five healthy pregnancies were monitored by neurobehavioural profile (quiet state or S1F and activity state or S2F percentages) and umbilical artery Doppler velocimetry (UA RI) on two occasions between the 27th-32nd and the 33rd-36th week of gestation. The aims of the present study were the following 1) to relate S1F, S2F and RI to mild and severe IUGR 2) to relate behavioural state analysis and UA Doppler velocimetry to the following perinatal outcomes: Cesarean section (CS); Preterm delivery (PD); small for gestational age (SGA); Apgar score at 1st and 5th min < 7; Respiratory Distress Syndrome (RDS); Neurological Injury (NI) (evaluated at the birth, the 4th, the 8th and the 12th month of life). 3) to establish the best predictors of perinatal outcome with these monitoring parameters by a stepwise computerized processing. Our results suggest: 1) mild IUGR, characterized by a progressive increase in peripheral vascular resistances, positive diastolic peak flow (RI: 0.72 +/- 0.01; mean +/- SD), is associated with gradual increase in S1F (12.51 +/- 2.84; mean +/- SD) and a decrease in S2F (27.51 +/- 2.81; mean +/- SD) percentages; 2) severe IUGR, characterized by zero or negative diastolic peak flow (UA RI-->1), is associated with a significant increase in S1F (21.32 +/- 12.11; mean +/- SD) and a decrease in S2F percentages (30.93 +/- 20.35; mean +/- SD). IN CONCLUSION: S1F is the best predictor of severe IUGR and significant for all the perinatal outcomes selected; S2F is the best predictor of mild IUGR and significant for SGA; UA RI is the best parameter for recognizing mild IUGR and evolution to severe IUGR.

Behavior↗
PubMed1994

[Benign insulinoma. Efficacy of preoperative treatment for persistent hyperinsulinemia using a synthetic somatostatin analog].

We investigated the 24-hour mean blood glucose and serum insulin (IRI), C peptide (C pep) and glucagon concentrations before (pre) and after (post) continued treatment with octreotide (100 mcg three time daily by s.c. injection) in a woman, 68 years old, affected by a nine years long benign insulinoma. The blood pool to dose 24-hour mean glucose and all hormone concentrations was obtained by equal quantities of blood samples taken every 2-hour over 24-hour. The IRI, C pep, glucagon, glucose circadian pattern and IRI/glucose ratio were determined on remaining blood portions. After continued treatment with octreotide was significantly reduced the exaggerated and inappropriate insulin (pre = 77.08 +/- 23.6 microUI/ml; post = 15.19 +/- 2.3 microUI/ml; p < 0.001) and C pep secretion (pre = 4.17 +/- 0.4 ng/ml; post--1.64 +/- 0.04; p < 0.001), while the blood glucose levels were significantly elevated (pre = 40.46 +/- 3.1 mg/dl; post = 132.46 +/- 6.9 mg/dl; p < 0.001). Also glucagon levels were significantly inhibited (pre = 73.53 +/- 12.19 pg/ml; post = 46.80 +/- 9.1 pg/ml; p < 0.05). The long-acting somatostatin analogue has improved a lot IRI/glucose ratio (pre = 1.9 +/- 0.4; post = 0.12 +/- 0.04; p < 0.001). A significant positive correlation was found between IRI and C pep before (r = 0.93; p < 0.001) as well after octreotide treatment (r = 0.85; p < 0.001). A significant positive correlation (r = 0.69; p < 0.008) between IRI and glucose was observed only after octreotide treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Unilateral reduction of head pain and facial vasodilatation after gasserian ganglion lesion.

The features of histamine-induced headache and its associated vascular responses were studied in 52 patients with different surgical lesions of the gasserian ganglion and in 12 control subjects. Certain features of headache (eg, intensity, type, and duration) were similar in patients and control subjects. However, the pain was absent on the side of the trigeminal lesion in 26 (50%) of the patients. This unilateral absence of pain was not related to the hypoesthesia that was caused by the operation, and it was associated with a decrease in vascular responses (histamine-induced facial flushing and increase in temperature) on the side operated on. These abnormalities were more prevalent in patients who had undergone thermocoagulation and presented with more severe damage of the trigeminal ganglion than in those who were subjected to trigeminal compression or glycerolization. The trigemino-vascular system seems to control headache of a vascular type and associated craniofacial vasodilatation in human subjects.

Aged↗
PubMed1993

Immunoreactivity to vasoactive intestinal polypeptide (VIP) in the hypothalamus of the domestic fowl, Gallus domesticus.

The distribution of VIP-immunoreactive neurons and fibers was detected in the hypothalamus of the chick by immunohistochemistry and light microscopy. A large amount of VIP cellular bodies was localized in the anterior and medial area of the hypothalamus with the highest density of cells in supraoptic, magnocellular preoptic, suprachiasmatic and paraventricular nuclei. Only few VIP-immunoreactive neurons were observed in the caudal section of infundibuli nucleus. A considerable concentration of VIP-positive fibers was also detected in the external layer of the anterior and posterior median eminence. Their presence might have origin both from the neurons of the infundibuli nucleus and from the cells of the paraventricular nucleus. Few VIP-immunoreactive fibers were revealed in the organum vasculosum of the lamina terminalis. These results tend to suggest that VIP may play more than one role in the hypothalamic regions, particularly in the preoptico-hypothalamic area. The presence of this peptide in the median eminence supports even more the hypothesis that it may be released into the portal circulation and transported to the pars distalis of the pituitary gland.

Animals↗