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Biomedical subjects

A Locatelli

Publications and source records attributed to A Locatelli.

At least 109 records · Page 6Linked to original sources
PubMed1994

Risk factors for pulmonary hypoplasia in second-trimester premature rupture of membranes.

OBJECTIVE: Our purpose was to determine the independent contribution of gestational age at rupture of membranes, latency period, and severity of oligohydramnios to the prediction of pulmonary hypoplasia in patients with second-trimester premature rupture of membranes. STUDY DESIGN: All women with premature rupture of membranes at < 28 weeks diagnosed between January 1982 and December 1990 were managed conservatively with a consistent protocol until intrauterine death or spontaneous or induced delivery. The diagnosis of pulmonary hypoplasia was made by strict pathologic and radiographic criteria. RESULTS: A total of 63 patients fulfilled the inclusion criteria. Pulmonary hypoplasia was present in 15 cases: two of nine stillborns, 12 of 25 neonatal deaths, and one of 24 survivors. All fetuses with pulmonary hypoplasia had oligohydramnios. Univariate analysis showed that the occurrence of pulmonary hypoplasia was significantly associated with gestational age at premature rupture of membranes (p = 0.002), oligohydramnios during the latency period (p = 0.005), and duration of the latency period (p = 0.02). However, logistic regression analysis showed that only the first two variables were independent predictors of pulmonary hypoplasia. CONCLUSION: Gestational age at premature rupture of membranes and oligohydramnios are independent predictors of the occurrence of pulmonary hypoplasia.

Adolescent↗
PubMed1994

Prognostic indicators in the prenatal diagnosis of agenesis of corpus callosum.

OBJECTIVE: Our aim was to determine the accuracy of ultrasonography in the prenatal diagnosis of agenesis of the corpus callosum and to establish whether ultrasonography can provide prognostic indicators in cases of agenesis of the corpus callosum. STUDY DESIGN: Prospective ultrasonographic study of the corpus callosum in all cases during an 8-year period in which fetal cerebral ventriculomegaly was detected. RESULTS: A total of 14 cases of agenesis of the corpus callosum are reported. In seven cases agencies of the corpus callosum was an isolated finding, and in seven cases it was associated with other abnormalities. Six cases involved mendelian syndromes (3 Lissencephaly syndrome, 2 Aicardi syndrome, and 1 Andermann syndrome), and one case was associated with trisomy 13. In 5 of 14 fetuses, all male, agenesis of the corpus callosum was an isolated benign finding. The corpus callosum could never be visualized before midgestation, but diagnosis of agenesis of the corpus callosum was very accurate after 20 weeks. CONCLUSION: Prenatal ultrasonographic findings suggestive of agenesis of the corpus callosum should be followed by a careful search for associated anomalies that may indicate genetic syndromes. Isolated agenesis of the corpus callosum is often an isolated, benign finding, particularly in male fetuses. In families at risk for mendelian syndromes associated with agenesis of the corpus callosum, lack of visualization of this structure is suggestive of the diagnosis.

Agenesis of Corpus Callosum↗
PubMed1994

Do uterine leiomyomas influence pregnancy outcome?

To evaluate the clinical significance of the presence, location, size, and number of uterine leiomyomas in pregnancy, a retrospective cohort study in which pregnancy complications and outcome of pregnant women with uterine myomas was undertaken by routine second trimester ultrasound examination. The case group consisted of 183 consecutive women with uterine myomas detected and followed during the years 1983-1989; the control group was made up of all pregnancies diagnosed and followed at the obstetric clinic during the period 1985-1987. The incidences of preterm delivery (less than 37 weeks), preterm premature rupture of membranes, in utero growth retardation (less than 5th percentile), placental abruptio, placenta previa, postpartum hemorrhage (more than 500 cc), and retained placenta were not significantly increased in the group of women with myomas compared with the general population. However, cesarean sections were more common in women with myomas (23 vs 12%; P < 0.001). Within the group of women with myomas, the incidence of cesarean section was not different in cases with multiple rather than solitary myomas, but it was significantly higher in cases of lower uterine segment compared with fundal myomas (39 vs 18%; P < 0.01) and when the mean diameter of the myoma was greater than 5 cm (35 vs 17%; P = 0.01). Stepwise logistic regression analysis showed that both myoma location and size were independent predictors of the odds of cesarean section.

Adult↗
PubMed1994

Central effect of rete testis fluid, inhibin 32K, and follicular fluid on plasma gonadotropin concentrations in sheep: inhibin is not the rete testis fluid protein able to suppress luteinizing hormone pulses.

We have previously shown that peripheral administration of rete testis fluid (RTF) proteins was able to suppress LH pulses through the suppression of LHRH pulses. This activity was named "LHRH Statin." The aims of the present work were to analyze LH inhibition after an intracerebroventricular injection of RTF and to determine whether inhibin is the factor responsible for this inhibition. Castrated rams (experiment 1) or ewes (experiment 2) received an intracerebroventricular injection of RTF, purified bovine inhibin 32K, bovine follicular fluid, or human serum albumin as control. Animals were bled every 15 min for 5 h before injection and for 7 h after injection. LH mean levels were significantly lowered (p < 0.01) only in the RFT-treated groups. FSH levels were not affected irrespective of group, source, or dose of inhibin. These experiments show first, that protein(s) present in ovine RTF can suppress LH secretion in sheep; second, that bovine follicular fluid or purified bovine inhibin 32K have no effect on LH secretion. Furthermore, the results suggest that centrally administered inhibin has no effect on FSH secretion under our experimental conditions. Together, these experiments clearly demonstrate that inhibin 32K does not exert any "LHRH statin" activity.

Animals↗
PubMed1994

Atrial natriuretic factor modifies noradrenaline release in a sodium-free medium.

1. The effects of atrial natriuretic factor (ANF) on 3H-noradrenaline (3H-NA) release evoked by a sodium-free medium (SFM) were studied. The experiments were carried out in rat hypothalamic slices incubated in vitro. 2. ANF (1, 10 and 100 nM) decreased NA release evoked by the omission of sodium in a concentration-dependent way. When calcium was omitted from a SFM, NA output was partially diminished. However, if ANF was added to the SFM/calcium free medium NA secretion showed no modifications. 3. Present results suggest that, in rat hypothalamus, NA release evoked by Na+ omission is divided into two fractions: one independent of and the other dependent on extracellular calcium. In addition, ANF modifies NA release evoked by SFM dependent on extracellular calcium.

Animals↗
PubMed1994

Evidence that melatonin binding sites in the pars tuberalis do not mediate the photoperiodic actions of melatonin on LH and prolactin secretion in ewes.

An experiment was designed to determine whether the pars tuberalis is the site of action of melatonin involved in the photoperiodic control of LH and prolactin secretion in sheep. In an attempt to produce a 'short-day' effect on these hormones (i.e. stimulation of LH secretion and inhibition of prolactin release), microimplants of melatonin were placed either around the pituitary stalk (n = 6) or in the third ventricle (n = 5) as a control for the efficacy of the microimplant. Two sham-operated groups were treated with empty microimplants around the pituitary stalk (n = 4) or in the third ventricle (n = 3). A further two control groups were given either no melatonin (n = 5) or a melatonin implant s.c. (n = 6). Administration of a melatonin implant s.c. is known to stimulate LH secretion and inhibit prolactin release in photoperiodically inhibited ewes. During the experiment (over 75 days), there was no significant increase in LH concentrations for the ewes receiving melatonin around the pituitary stalk. A similar lack of response was noted in the untreated or sham-treated ewes. In contrast, LH concentrations increased in ewes treated with the melatonin microimplant in the third ventricle on day 37 (+/- 4) and remained high until day 62 (+/- 4). Similarly, in the ewes given an implant s.c., LH concentrations rose on day 39 (+/- 4) and remained high until the end of the study. Furthermore, melatonin caused an inhibition of prolactin secretion relative to controls only when delivered to these sites (i.e. s.c. and into the third ventricle, but not around the pituitary stalk).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Potential antitumor agents. XX (1). 6-Anilinoimidazo[2,1-b]thiazoles.

The synthesis of 6-anilinoimidazo[2,1-b]thiazoles, related to the well-known antitumor agent amsacrine, is reported. The cytotoxic activity of the new compounds was evaluated on HeLa cells. Compound 3a, the most closely related to amsacrine, was significantly active.

Antineoplastic Agents↗
PubMed1993

Ram-induced short luteal phases: effects of hysterectomy and cellular composition of the corpus luteum.

Two experiments were conducted on Préalpes ewes to test 2 complementary hypotheses which may explain the short lifespan of corpora lutea observed in some cases after ram-induced ovulation: i) the possible role of the uterus was tested by determining the effects of hysterectomy on the duration of luteal phases after the ram effect (RE); ii) the possible difference due to characteristics of follicles before ovulation was tested by determining the cellular composition and characteristics of corpora lutea (CL) induced by the RE compared to CL of the breeding season (BS) when ovulation is synchronized by FGA-impregnated sponges. In the first experiment, 9 ewes were hysterectomized (Hys) and introduced to rams at the same time as 10 control ewes. Plasma progesterone (P4) was analyzed each day for 17 consecutive d after the introduction of rams. The number of females ovulating was not different for the 2 groups (7/9 vs 9/10, respectively), but no Hys ewes experienced short cycles compared to 5 of the 9 control ewes (P = 0.029). The second experiment involved 16 ewes subjected to the RE in June, and 5 cyclic ewes in January. The ewes were ovariectomized 82 h after the preovulatory LH surge, the CL were separated, weighted and the luteal cells enzymatically dissociated to count the relative proportions of small (< 20 mu diameter) and large cells and assess in vitro P4 secretion both with and without stimulation with 100 ng ovine LH. Plasma P4 concentration increased significantly more slowly in RE than in BS eves (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Evidence for a protein-like factor from "rete testis" fluid that suppresses luteinizing hormone-releasing hormone (LHRH) pulses (LHRH statin): a new hormonal activity?

Signals that modulate LH-releasing hormone (LHRH) pulse frequency are fundamental mechanisms for regulating important reproductive processes. Gonadal steroids are presently considered to account for the entire gonadal feedback mechanism that modulates LHRH secretion. However, we have previously suggested that a testicular protein(s) present in charcoal-treated rete testis fluid (ctRTF) can suppress LH pulsatility in the ram. The present experiments were aimed at determining whether the disappearance of LH pulses induced by ctRTF administration implicate a hypothalamic or a pituitary site of action. Thus, we have examined the effects of ctRTF peripheral administration on 1) the LH response to LHRH, 2) LHRH portal blood levels, and 3) LHRH content in hypothalamic tissue. Finally, the effects of ctRTF administered into the third ventricle on plasma LH levels were assessed. The present results show that a testicular protein(s) is able to suppress LHRH pulse frequency without affecting amplitude and without any effect on the LH response to LHRH (LHRH Statin). The observation that an active dose administered by the intracerebroventricular route is 0.0005 the active dose needed by the peripheral route reinforces this evidence. These data lead to the new concept that the testicular signals that govern LHRH pulse frequency may be not only steroids, but also proteins.

Animals↗
PubMed1993

Effects of a single brief period of moderate heating of the testes on seminiferous tubules in hypophysectomized rams treated with pituitary extract.

An experiment was conducted to examine the appearance of the seminiferous tubule 20 days after a single exposure of the testes of rams to a scrotal temperature of about 42 degrees C for 45 min. Ten of the animals were surgically hypophysectomized and five were simultaneously heated; these rams were treated twice a day with ovine pituitary extract to avoid modifications in the negative feedback from the testes to the pituitary and consequent changes in gonadotrophin secretion. Six intact rams (three heated and three unheated) were also studied. The pituitary extract significantly increased the testis weight and spermatogonial multiplications from A1 spermatogonia onwards. Twenty days after the heat treatment, testis weight was significantly reduced by heating; both tubular and intertubular tissues were affected. The total length of seminiferous tubules per testis was not modified, whereas the mean seminiferous tubule diameter was significantly reduced after heating. The total number of Sertoli cells per testis was not significantly modified, while their mean cross-sectional nuclear area was significantly reduced by heat treatment. A decrease in the number of all germ cells except A0 spermatogonia, from A1 spermatogonia onwards, was observed. The number of round spermatids decreased by 95 and 90%, slightly more than the diplotene primary spermatocytes (76 and 77%) and elongated spermatids (79 and 85%) in hypophysectomized pituitary extract-treated and intact rams, respectively. Round and elongated spermatids would be derived from germ cells that were respectively leptotene and young pachytene primary spermatocytes at the time of heating, whereas diplotene primary spermatocytes would have been type B spermatogonia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Potential antitumor agents. 23.(1) Cytotoxic and differentiating activity of compounds related to hexamethylenebisacetamide.

The synthesis of potential differentiating agents related to hexamethylenebisacetamide (HMBA) is reported. 1,6-Bis(3,3-dimethyl-2-oxo-2,3-dihydroindol-1-yl)hexane (4) and 1,6-bis(4-carbamoyl-thiazol-2-yl)hexane (9) were not soluble enough to allow biological testing. For this reason the dipotassium salt (10) of 1,6-bis(4-carboxy-thiazol-2-yl)hexane (11) was prepared. The salt 10, tested in the human rhabdomyosarcoma cell line (RMZ) and in the murine Friend erythroleukemia cells (MEL), proved more cytotoxic than HMBA, but was devoid of differentiating activity. Compounds 4, 9, 10 and 11, tested on HeLa cells (in vitro) and on Ehrlich ascites (in vivo) did not show antitumor activity.

Acetamides↗
PubMed1993

[Refinement of a new Doppler sensor for studying fetal hemodynamic disorders (animal model)].

Fetal Doppler techniques applied in the human have furnished information of the regional haemodynamics of fetal circulation but has in general been associated with haemodynamic data obtained by vessel puncture, i.e. arterial pressure or blood gases. With animal models, further data can be obtained in the course of induced pathologies or during dynamic test (hypoxia, drugs). Several studies on utero-placental haemodynamics have been conducted using electromagnetic sensors and implanted catheters. This type of technique is only possible for certain vessels (usually the cord vessels) and, for example, cannot be used to investigate the cerebral area. The aim of this work was to develop a Doppler sensor which could be implanted in utero on the fetus and would permit a real time measurement of the major fetal blood flows. The sensor was made of 2 continuous Doppler transducers (13 mm x 4 mm) with a 45 degrees inclinasion to the sensor surface and carried on a parallellopipedic support system measuring 20 mm x 6 mm. The active surface of the transducer has a silicone film covering. The sensor is placed on the skin of the fetus, facing the artery to be explored, and oriented towards capture of a quality signal. The sensor is then sutured to the skin and the coaxial leads of the 2 transducers are exposed through the skin of a pregnant ewe. The leads are connected to a Doppler control panel later after the operative period. Three sensors can be implanted simultaneously to monitor umbilical, cerebral and uterine blood flows.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

New implanted Doppler sensors for the assessment of the main fetal hemodynamics.

If the fetal Doppler examination during human pregnancies provides useful information to the obstetrician, it does not allow us to collect all the biological and haemodynamic data required to understand the physiopathological mechanisms involved in the development of intrauterine growth retardation (IUGR) and hypoxia. With the animal model, it is possible to have access to the blood pressure, the blood velocity and volume, to collect blood sampling and to perform pharmacological tests, or to simulate some human pathology. Several studies have been already carried out on lamb fetuses using electromagnetic flowmeters placed around the cord and catheters, with pressure sensors placed inside the fetal aorta. Most of the time only the umbilical flow was assessed on the fetal side. The aim of the present work was to develop a new Doppler system able to monitor in real time and simultaneously, the fetal cerebral and the umbilical arterial flows as well as the uterine circulation. New flat Doppler probes have been designed, to be implanted on the fetus and on the mother, which makes possible the atraumatic assessment of fetal and maternal flows during approximately 20 days. The 4-MHz CW Doppler probe consists of two rectangular piezoelectric transducers of 13-mm wide, preoriented at 45 degrees from the surface of the probe, placed in a 6-mm-high plastic case in which small holes are made to sew the probe on the fetal skin. The sensors are fixed on the fetal skin, facing the umbilical cord, the fetal cerebral arteries and in front of the uterine arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗