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Biomedical subjects

S Giannini

Publications and source records attributed to S Giannini.

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

Insulin-like growth factor-I receptors in human hyperplastic prostate tissue: characterization, tissue localization, and their modulation by chronic treatment with a gonadotropin-releasing hormone analog.

Insulin-like growth factor I (IGF-I) receptors were characterized in membranes obtained from prostate tissue of patients affected by benign prostatic hyperplasia (BPH) before and after treatment with a GnRH agonist analog. Binding of [125I]IGF-I to membranes obtained from untreated patients was specific and time and temperature dependent. Analysis of the binding data yielded two classes of binding sites, one of high affinity (Kd, 10(-11) mol/L) and one of lower affinity (Kd, 10(-9) mol/L). BPH membrane preparations were affinity-cross linked to labeled IGF-I, and then subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Analysis by autoradiography revealed one labeled protein with an apparent Mr = 300K under nonreducing conditions and two labeled protein with Mr = 270K and Mr = 130K under reducing conditions. Excess unlabeled IGF-II reduce both of them, whereas the same excess of IGF-I completely abolished them. In membrane preparations of prostatic tissues from patients affected by BPH and treated for 2 months with a GnRH agonist analog, the binding capacities of both binding sites were significantly higher than those of BPH tissue from untreated patients, whereas binding affinities were unchanged. The IGF-I receptor in BPH prostate tissue of untreated patients was mainly localized in the basal layer of the epithelium, as demonstrated by immunohistochemical staining, whereas in the tissue from treated patients positive staining was found also in the glandular epithelium. These results demonstrate that: 1) specific binding sites for IGF-I are present in prostatic tissue from patients with BPH, 2) androgen deprivation increases their binding capacities and seems to modify their epithelial localization.

Aged↗
PubMed1991

Oxytocin and V1 vasopressin receptors in rabbit endometrium during pregnancy.

Neurohypophysial hormone receptors were identified and characterized in rabbit endometrium and decidua by radioligand binding methods. The results strongly support the presence of a heterogeneity of sites in the decidua of parturient rabbits. The oxytocin site (R1) binds oxytocin and oxytocin analogues ([Thr4, Gly7]oxytocin and OTA) with high affinity, whereas the AVP site (R2) was selective for the V1 AVP analogues, [Phe2, Orn8]VT and d(CH2)5TyrMeAVP. The concentration of oxytocin receptors was low (50-100 fmol/mg protein) at oestrus (Day 0) and on Day 29 of pregnancy, but increased significantly (about 8-fold, P less than 0.05) during parturition. Conversely, V1 AVP receptors were more concentrated than the oxytocin sites at the end of pregnancy (150 fmol/mg protein) but did not change during parturition. These results indicate that neurohypophysial hormones have specific receptors not only in the myometrium but also in the uterine mucosa and we suggest that these receptors may participate in the regulation of uterine activity during pregnancy.

Animals↗
PubMed1990

Effect of nifedipine on urinary excretion of calcium and calcium-controlling hormones in essential hypercalciuria.

Nifedipine has been shown to lower urinary calcium in "essential" hypercalciuria. However, the mechanism(s) by which this action takes place is completely unknown. This study describes the effect of nifedipine on some calcium-controlling hormones in essential hypercalciuria. Nifedipine (20 mg/day) was administered to ten essential hypercalciuric patients, and urinary PgE2, plasma bicyclic PgE2, 1,25 vitamin D3, and PTH were assayed before and after drug administration. Nifedipine promoted a significant fall in urinary calcium (352.1 +/- 87.67 SD vs. 231.2 +/- 74.62 mg/hr; t = 7.35, p less than .0001) and PgE2 (343.92 +/- 42.71 vs. 245.03 +/- 35.41 SD ng/24 hr; t = 6.18, p less than .0002), as well as in plasma bicyclic PgE2 (310.00 +/- 30.91 vs. 200.00 +/- 31.62 SD pg/ml; t = 9.86, p less than .0001) and 1,25 (OH)2 vitamin D3 (32.77 +/- 3.23 vs. 26.94 +/- 2.94 SD pg/ml; t = 6.53, p less than .0001), while PTH remained unaltered (18.50 +/- 3.63 vs. 19.50 +/- 4.09 SD ng/ml; t = 0.85, p, ns). Urinary calcium and PgE2 correlated positively before (r = 0.81, p less than .005) but not after treatment. The fall in urinary PgE2 brought about by nifedipine seems to be due to an inhibition of PgE2 synthesis, since the absolute decrements in both urinary PgE2 and plasma PgE2 metabolites were positively correlated (r = 0.79, p less than .007). No correlation was found between the absolute decrements of plasma bicyclic PgE2 and 1,25 (OH)2 vitamin D3. These data seem to suggest that the fall in urinary calcium brought about by nifedipine is in some way related to PgE2 synthesis inhibition and to uncoupling of 1,25 (OH)2 vitamin D3 and PTH action.

Adult↗
PubMed1990

Is hydrochlorothiazide-induced hypocalciuria due to inhibition of prostaglandin E2 synthesis?

1. Since prostaglandin E2 could play a role in idiopathic hypercalciuria, and considering the well-established hypocalciuric action of hydrochlorothiazide, we have evaluated the effect of 15 days' treatment with hydrochlorothiazide in 10 hypercalciuric male stoneformers on urinary Ca2+ and prostaglandin E2, as well as on plasma bicyclo-prostaglandin E2, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and parathyroid hormone. 2. In addition to lowering urinary Ca2+ (P less than 0.001), hydrochlorothiazide also promoted a significant fall in urinary prostaglandin E2 (P less than 0.001), plasma bicyclo-prostaglandin E2 (P less than 0.001) and 1,25-dihydroxyvitamin D (P less than 0.01), and an increase in plasma parathyroid hormone (P less than 0.025), whereas plasma 25-hydroxyvitamin D was unchanged. 3. A positive correlation between urinary Ca2+ and prostaglandin E2 was present before (P less than 0.00005), but not after, hydrochlorothiazide. Plasma bicyclo-prostaglandin E2 and plasma 1,25-dihydroxyvitamin D were positively correlated both before (P less than 0.005) and after (P less than 0.005) hydrochlorothiazide, as was also the percentage change in each induced by the drug (P less than 0.05). Furthermore, the changes in plasma 25-hydroxyvitamin D and plasma 1,25-dihydroxyvitamin D after hydrochlorothiazide were negatively correlated (P less than 0.05). 4. It is suggested that a block of prostaglandin E2 synthesis plays a role in the effect of hydrochlorothiazide on Ca2+ metabolism, most probably through an inhibition of 1 alpha-hydroxylase activity.

Adult↗
PubMed1990

Neurohypophyseal hormone regulation of endothelin secretion from rabbit endometrial cells in primary culture.

Immunoreactive endothelin-1 (IR-ET-1) was detected in the cultured medium from endometrial but not myometrial cells of rabbits in primary culture using a specific radioimmuno assay (RIA). Similar results were obtained with a radioreceptor assay using myometrial membranes. In a reverse-phase HPLC synthetic ET-1 and IR-ET-1 of the extract medium from endometrial cells revealed essentially the same elution profiles, as determined by RIA. Two selective agonists of oxytocin (OT) or V1 vasopressin (VP) receptors produced, respectively, a 6- and 2-fold increase of IR-ET-1 release from endometrial cells. These effects were completely reversed by the addition of two specific antagonists of OT and V1 VP receptors. Our results indicate that ET-1 is produced and released in the culture medium of rabbit endometrial cells in primary culture. The release of ET-1 is under receptor-specific control by neurohypophyseal hormones.

Animals↗
PubMed1990

Human myometrium during pregnancy contains and responds to V1 vasopressin receptors as well as oxytocin receptors.

We have recently demonstrated the presence of two classes of neurohypophysial hormone receptors in the vagina, myometrium, and oviduct of rabbit: an oxytocin (OT) site and a V1 arginine vasopressin (AVP) site. We now report binding and in vitro contractility studies on human myometrial specimens obtained at cesarean section from women at the end of pregnancy. The program Ligand was used to analyze self- and cross-displacement curves for labeled OT, AVP or its V1 antagonist d(CH2)5TyrMeAVP, the corresponding unlabeled peptides, and selective analogs. Our results clearly indicate the presence of heterogeneity of binding sites in human uterus. Blocking experiments were performed to evaluate the density of OT and V1 AVP receptors in individual uterine specimens. The contractile response of the same samples to OT, AVP, and analogs was also evaluated. Our results indicate that V1 AVP receptors are present in all of the uterine specimens investigated, with virtually equal density from 32 weeks to term. AVP and the V1-selective agonist [Phe2,Ile3,Orn8]VP stimulate contractility of uterine strips, an effect blocked by nanomolar concentration of the V1 antagonist d(CH2)5TyrMeAVP. Uterine OT receptors increase during late pregnancy, peaking in early labor. A significant correlation between the density of OT receptors and the frequency of uterine contractions (external tocography) was found in pregnant women before surgery. OT stimulated in vitro contractility of uterine strips only when the density of receptors was more than 150 fmol/mg protein. In conclusion, we identified biologically active V1 AVP receptors in human uterus at the end of gestation and confirmed the primary relevance of OT receptors in human parturition.

Adult↗
PubMed1989

Biological osteosynthesis in osteochondral lesions of the talus.

Osteochondral lesions of the dome of the talus whether medial or lateral are rare. Surgical treatment is required when there is a loose body, or when the lesion is symptomatic and resistant to nonsurgical treatment. Usually, the degenerated fragment is removed, followed by curettage and multiple perforations of the subchondral bed, but different methods may be used to reinsert the osteocartilaginous fragment. Having been satisfied with our first studies conducted both on animals and man, we began to reinsert the osteochondral fragment by using resorbable means of synthesis. The purpose of this study is to report our experiences with 3 such cases at a minimum follow-up of one year.

Adolescent↗
PubMed1989

[The incidence of postural headache in in- and outpatients following lumbar myelography (needles of different gauges and headache)].

The incidence is reported of postural headache and other types of headache arisen after myelography in a pilot sample of 540 patients, divided into 3 groups. The myelographic study was performed on the first two groups using 20 and 22 gauge needles, and with 25 gauge needles on the third group. 140 patients in the third group were treated on an outpatient basis, and 25 of them underwent myelo-CT. Myelography was performed on all the patients in the second and third group in erect position. In the authors' opinion, the erect position and the use of a fine needle determined a considerable reduction in post-myelographic side effects, i.e. postural headache.

Adolescent↗
PubMed1988

Efficacy of captopril in hypertensive diabetic patients.

Twenty hypertensive diabetic patients (10 with type I and 10 with type II) were treated with captopril, 50 mg twice a day, for three months. The drug was effective as monotherapy in 16 patients. An additional nine months of follow-up was obtained in 12 of these patients (four with type I and eight with type II) who did not need the addition of diuretics to achieve normal blood pressure. For these patients with long-term treatment, since there was no substantial difference between those with type I and those with type II, the data were pooled. Mean arterial pressure significantly decreased shortly after treatment was begun and the reduction was maintained. No significant change was induced by captopril in urine volume, osmolar clearance, and serum and urinary values of sodium, chloride, calcium, and magnesium, whereas significant reduction was found in fractional excretion of potassium and phosphate. The baseline levels of proteinuria were only slightly elevated, yet they fell in all patients during treatment. All patients maintained satisfactory control of carbohydrate metabolism, and none of them required substantial changes in hypoglycemic treatment. The administration of captopril as monotherapy appears to be an effective and safe way of lowering blood pressure in diabetic hypertensive patients, even in the long term, without effects on renal function and in carbohydrate metabolism.

Adult↗
PubMed1988

Surgical correction of cervical hyperextension in rigid spine syndrome.

The rigid spine syndrome is a condition characterized by a mild axial and proximal myopathy in which the fibrous shortening of spinal extensor muscles causes a marked limitation in flexion of the spine. This 10-year-old boy with rigid spine syndrome showed a progressive limitation in flexion of the cervical spine with fixed hyperextension of the neck. To look forward he had to bend forward his trunk flexing hips and knees. An X-ray study demonstrated a progressive limitation in flexion but also in extension of the cervical spine. A particular radiologic aspect named "Alligator sign" was demonstrated. The hyperextension of the neck was corrected surgically by opening the interspinous spaces from C2 to C7 through a capsulotomy. The correction was stabilized with bone grafts fixed to the spinous processes. This boy with the straightened cervical spine was then able to look forward without any compensatory posture.

Cervical Vertebrae↗
PubMed1988

Mechanism of class switching.

We have documented the action of unequal sister chromatid exchange on antibody genes, and our studies provide the first molecular description of an unequal sister chromatid exchange event. We delineated the sequences that mediate class switch recombination in normal B cells through genomic Southern analysis of five IgG2-producing hybridomas. Successive subclass switching was documented in two of eight maps and may possibly account for interposed DNA in three additional maps, implying that subclass switching may be a relatively frequent occurrence in normal B cells. As in most other myelomas and hybridomas, the 5' breakpoint of switch recombination in our panel of hybridomas falls 5' to Cmu-associated tandem repeats, whereas the 3' breakpoint falls within C gamma-associated tandem repeats. We consider various hypotheses in the text, the most interesting of which is that deletion of Cmu-associated tandem repeats is a necessary first step before class switch recombination in mature B cells. This hypothesis suggests that Cmu-associated tandem repeats may be a separately regulated DNA element.

Animals↗
PubMed1988

Vasopressin and oxytocin receptors in vagina, myometrium, and oviduct of rabbits.

In view of the presence of distinct oxytocin (OT) and vasopressin (VP) receptors in the male genital tract (porcine) we have reexamined the receptors for OT and AVP in the classical OT target tissue, female genital tract (rabbit). Neurohypophysial hormone receptors have been investigated in vagina, myometrium, and oviduct using quantitative ligand binding, adenylate cyclase, and contractility studies. Our results clearly indicate the presence of distinct OT and V1 VP receptors in the myometrium, while only the latter was detected in vagina and oviduct. In myometrium, estrogen treatment increases the density of OT and AVP receptors, while progesterone administration inhibits the estrogen effect. At the time of spontaneous delivery a dramatic (17-fold) increase was observed for the OT sites, while the AVP sites were unchanged. AVP receptors in vagina were sensitive to sex steroid administration and were reduced during pregnancy and delivery. Isometric contractility studies suggest that not just OT, but AVP can stimulate uterine strips, an effect that is partially reversible by the V1 antagonist d(CH2)5TyrMeAVP. In vagina only AVP is effective in inducing contractions at nanomolar concentrations. These results suggest a role for AVP as well as OT in regulation of the motility of female genital tract.

Adenylyl Cyclases↗
PubMed1987

Ultrasonography in pathological conditions of muscles, tendons and joints.

The authors discuss the use of ultrasonography in the investigation of pathological condtions of muscles, tendons and joints. The indications and related ultrasonographic findings are presented. The importance of this method is emphasized both as an aid to diagnosis and choice of treatment. Its use in evaluating the effectiveness of treatment is also discussed.

Elbow Joint↗