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Biomedical subjects

U Simeoni

Publications and source records attributed to U Simeoni.

At least 55 records · Page 3Linked to original sources

Urinary tract infections with tissue penetration in children: cefotaxime compared with amoxycillin/clavulanate.

In children, the site of urinary tract infection (acute pyelonephritis or cystitis) cannot usually be accurately determined from the clinical presentation. The severity of the urinary tract infection (risk of renal scars) is best correlated with its estimated degree of tissue penetration clinically (fever, general condition) and on laboratory tests (sedimentation rate, C-reactive protein). The duration of parenteral antibiotic therapy, especially in children (taking account of difficult venous access and the cost of hospitalization) needs to be specified beyond the initial period required for sterilization of the urine (usually less than 48 h). We conducted a study in children older than one year to compare the efficacy and tolerance of two treatment regimens for urinary tract infection with tissue penetration: cefotaxime 100 mg/kg/d in four divided iv doses for 14 days (group I) and amoxycillin/clavulanate 100 mg/kg/d in four divided iv doses for seven days with conversion to the oral route at a dosage of 50 mg/kg/d for seven days (group II). The randomised protocol included ten patients in each group, comparable with respect to sex, age and history. Clinical efficacy (time until the patient became afebrile), bacteriological efficacy (sterilization of the urine), and biological efficacy (time to normalization of the indices of the acute inflammatory response) were identical for both groups regardless of the duration of iv antibiotic treatment (seven days for amoxycillin/clavulanate; 14 days for cefotaxime). The only side effect was diarrhoea, which affected three patients and did not require modification of the oral treatment regimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Amoxicillin↗

Pharmacokinetics of teicoplanin in children.

A single dose of 6 mg/kg teicoplanin was infused over 10 min in six children of mean age 7 years, and a single dose of 6 mg/kg was infused over 20 min in four neonates of mean age 8.5 days. Serum sampling was performed at 0 and 10 min and at 1, 4, 12 and 24 h and thereafter 24-hourly, up to ten days. Urine was collected for each 24 h throughout the study in children. Teicoplanin was assayed by high performance liquid chromatography. Tolerability of teicoplanin was excellent both in children and in neonates. For all the patients the serum concentrations of teicoplanin followed an open two-compartment model. Mean Cmax was 48.6 +/- 16.7 mg/l (10 min) in children, and 19.6 +/- 1.05 mg/l (20 min) in neonates, and mean t1/2 beta was 20.5 +/- 5.5 h and 30.3 +/- 6.3 h, respectively. On the basis of the results dosage recommendations for children and neonates are made.

Adolescent↗

[Extra-osseous and intra-osseous microvascularization of the sternum of the child].

The microvascularization of the sternum of the child has been studied by a method of India ink injection and by histology. Extra-osseous vasculature includes vascular pedicles and sternal vascular networks. Vascular anterior and posterior pedicles issue from internal mammary vessels. Sternal anterior and posterior networks are disposed on the faces of the sternum and are divided in a superficial one and a deep one; both are included in the perichondrium. In newborns and in young infants, vascular structures looking like baskets are affixed to the deep sternal network. It is unlikely that they intervene in the constitution of the adult pattern of the sternal vasculature. The early complete development of sternal networks contrasts with the existence of evolutive characteristics of the intra-osseous vasculature. Intra-osseous vasculature includes the cartilage canal vessels and the vessels of the ossification centers. Cartilage canals are provided with an axial artery, issued from the deep sternal network, which produces short capillaries which continue in peripheral sinuses. Cartilage canals permit the penetration of perichondral tissue deep in the cartilage of the developing sternum, allowing the formation of the ossification center. The ossification center is vascularized by centrifugal arteries, issued from the cartilage canal artery, and disposed in a radiant pattern. They continue, through a conical progressive dilatation, into a sinusoid network, which presents a convergent disposition towards the center of the ossification point. Vascular events precede ossification. Hematopoietic development is consecutive to the vascular events too. The slenderness of vascular pedicles contrasts in neonates with the wide development of the sinusoid network. Adipose tissue is rare in the bone marrow sternum of the child. Secondary evolution of the ossification center vasculature permits its connections with the deep sternal vascular network, with adjacent cartilage canals, and with adjacent ossification centers. Progressively, the number and the importance of the peripheral pedicles of the ossification centers increase. Thus, a multiple and centripetal vascular provision takes the place of the initial, unique, centrifugal one. These modifications correspond to the transition from the vascular pattern of an expanding structure (the ossification center) to the one which is adapted to the full expression of its hematopoietic function.

Adolescent↗

[Urinary infections in children].

Urinary tract infection is frequent in childhood, usually without major consequences. Its diagnosis is often overestimated and needs precise bacteriological and cytological tests; systematic exploration of the urinary tract must be proposed if these tests are positive. The clinical presentation and the incidence of uropathies is strongly related to age. The therapeutic protocol will depend on germ, age, symptoms and results of morphological examinations.

Anti-Bacterial Agents↗

[Severe theophylline poisoning in children. Value of hemodialysis with high permeability membrane].

The authors report a massive accidental ingestion of enteric-coated theophylline (Armophilline ) by a young child. A status epilepticus and elevated theophylline serum concentration (167 mg/l) led to use hemodialysis with high dialytic clearance. The elevated clearance was obtained by the use of high permeability membrane, by bicarbonate dialysate and the best quality of vascular access (Hickman catheter).

Child, Preschool↗

[Microvascularization of the sternum in children].

46 sternums originating from 1-day- to 17-year-old children were injected with India ink and transparified. The intraosteal and medullary vasculature is described at different stages, as well as cartilage canals, vessels of the isolated ossification center, vessels of the ossification center connected with peripheral vascular structures or neighboring cartilage canals, and finally the transition to the adult pattern. With age, the centrifugal vascular distribution develops to a centripetal pattern.

Adolescent↗

[Persistent hyperbilirubinemia after intrauterine intraperitoneal transfusions in 4 newborn infants. Role of intraperitoneal red cells present at birth].

Four neonates who had undergone intra-uterine peritoneal blood transfusions for Rhesus disease and hydrops fetalis presented, during the first days of life, with intractable hyperbilirubinemia in spite of multiple exchange transfusions. The hyperbilirubinemia was due to delayed absorption and hemolysis of peritoneal red cells. This unusual complication can be successfully managed with peritoneal lavage which should be performed when the antenatal history is contributive for low absorption of transfused blood.

Blood Transfusion, Intrauterine↗

[Chickenpox and pregnancy. Perinatal aspects and prevention].

Five neonates born to women who had had varicella late in pregnancy or in the post-partum were admitted to our unit during the last year. In utero transmission of varicella-zoster virus occurred in 2 cases. One of them had no clinical eruption but specific IgM at a titer of 1/200. The mother presented with varicella 15 days before delivery. The other developed severe neonatal congenital varicella (with disseminated eruption, pneumonia and seizures). She was treated by Aciclovir (15 mg/kg/8 h). The mother presented with chickenpox 24 hours after birth. Varicella occurring in a pregnant woman from 4 days before to 2 days after delivery is dangerous because the baby will lack maternal antibodies. It may develop severe neonatal varicella (mortality: 20-30%). A neonate in critical condition was successfully given a prophylactic treatment by Aciclovir IV (15 mg/kg/8 h for 5 days) and varicella-zona immunoglobulins (2 ml on days 1, 2, 3). This approach may be the best treatment for babies at risk for severe neonatal varicella.

Chickenpox↗

Antenatal diagnosis of upper urinary tract dilation by ultrasonography.

The criteria for the detection of fetal pyelectasis are still controversial. Prenatal and postnatal data from 2,170 consecutive pregnant women who underwent at least one antenatal ultrasound scan were prospectively studied. Fetal pyelectasis was defined on the basis of a mean renal pelvis dimension > 5 or 10 mm before or after 28 weeks of gestation, respectively. Pyelectasis was detected in 95 (4.4%) fetuses. Eighty-nine among them were explored after birth. In 13 (13.7%) cases, an obstructive urinary tract abnormality, a severe vesicoureteral reflux, or a megaureter were diagnosed postnatally. In 29 (30.5%) cases, pyelectasis was confirmed postnatally, while complementary investigations ruled out an obstruction of the urinary tract. The incidence of urinary tract malformations was thus 0.60%, while the positive predictive value was 13.7%. We recommend to use a value not < 10 mm of the renal pelvis mean dimension beyond 28 weeks of gestation as a threshold for detection of fetal upper urinary tract obstruction, in the absence of ureteric and/or bladder dilation. Any value between 5 and 10 mm measured during the 2nd trimester of gestation should be confirmed by a second ultrasound examination performed during the 3rd trimester, before being considered pathological.

Chromosome Aberrations↗

Renal effects of antenatally or postnatally administered steroids.

Steroids administrated antenatally to the mothers improve postnatal outcomes of the newborns with pleiotropic effects. Furthermore steroids have been used in preterm infants to prevent or treat chronic lung disease. Synthetical glucocorticoids readily cross placental barrier and reach significant pharmacologic levels in the fetus: besides their well known pulmonary effects they have a concomitant maturational effect of postnatal renal function in preterm infants both with a direct and indirect effect. Endogenous and exogenous glucocorticoids play a role in the maintenance of glomerular filtration (GFR). The antenatal administration of steroids increases the GFR, in association to the maturation of the tubular function. According to different studies the improvement of renal function, expressed by the increase of GFR, is only partially referable to the increase of MAP and the improvement of the cardiovascular status, while it was imputable to a direct renal effect of the steroids, especially on the renal blood flow, on functional glomerular surface area available for filtration and on the glomerular filtrate of the single cortical nephron. However debate remains about the mechanism through which steroids would act on the renal vascular smooth muscolature. The increase the GFR observed after the antenatal administration of glucocorticoids in premature fetuses is also accompanied by an increase of urinary flow and of fractional excretion of sodium. Glucocorticoids would increase the proximal reabsorption of sodium increasing directly the function and the expression of the sodium transporters and both indirectly and directly increasing the activity of Na-K-ATPase. In extremely low weight antenatal administration of betamethasone or dexamethasone was associated with lower estimated insensible water loss, secondary to a direct maturational effect in the skin epithelial barrier, as well as an increased reabsorption of the fetal lung fluid. Moreover antenatal glucocorticoid administration was associated, at birth, to a significant suppression of plasma renin activity and angiotensin II in comparison to the controls. Despite the wide use of the steroidal therapy in the prevention of the bronchopulmonary dysplasia, only few articles, in literature, analyse the effects of glucocorticoids on postnatal renal function, such as the increase in urinary flow. The authors think that steroids contribute in a meaningful way to the clinical improvement observed in children with BPD through the maturative action on the premature kidney with effect both at glomerular and tubular level.

Female↗

[Efficacy of early cerebral MR in the detection of brain lesions in high risk preterm infants compared with conventional US].

To identify the efficacy of early cerebral MR, performed in the first month of birth, in the detection of brain lesions in high risk preterm infants, compared with conventional US, we recruited into the study a group of 30 preterm infants born at or below a gestational age of 30 weeks, who had a pathologic scan. The findings on US were compared with those of the early MR scan, performed in the same days, the results of which were considered as the final diagnosis. The value of cranial US as a predictor of MR signal intensity was assessed by calculating sensitivity, specificity, positive and negative predictive values. Agreement between two investigations was evaluated by calculating the K coefficient. US showed 33 haemorrhagic lesions in 25 preterms; MR showed 27 haemorrhagic lesions in 22 infants: in 16 cases MR gave the same results of US. Cranial US was reliable in detecting lesions such as GLH and IVH, but less sensitive in the definition of their size and distribution. Sensitivity of US for haemorrhagic lesions was 96.3%, PPV 78.8%, K coefficient 0.55 (p < 0.001). About the White Matter, cranial US demonstrated 20 lesions in 20 preterms; MR showed 16 lesions in 16 infants: in 3 cases MR was agree to US. US showed high reliability in the detection of cystic lesions, but significant limitations in the demonstration of non-cystic injury. We founded that normal WM echogenicity on US is not a good predictor of normal WM signal intensity on MR (30%). Sensitivity of US for WM lesions was 81.3%, PPV 65%, K coefficient 0.23 (p = 0.04). Finally US showed 4 lesions in other brain locations, MR confirmed 3 of them and discovered other 10. Sensitivity of US for these lesions was 23.1%, PPV 75%, K coefficient 0.21 (p = 0.11). We founded that cranial US is a good method for detecting GLH, IVH, HPI and severe WM lesions (cystic PVL), but it can miss non-cystic PVL, punctate haemorrhages, WMD and lesions in other brain locations, that, on the other hand, MR detects clearly.

Brain Diseases↗

Vascular mechanisms in the developmental programming of cardio-vascular disease.

Several studies suggest that adverse events during foetal life can program cardiovascular diseases in adulthood. Barker et al. identified a relationship between low birth weight and an increased risk of arterial hypertension, carotid arteriosclerosis, and mortality by coronary heart disease or stroke in adulthood. These findings led to the "foetal origins" hypothesis, which is that cardiovascular disease originates in the adaptations to an adverse intrauterine environment. Such adaptations may permanently alter the cardiovascular structure and physiology through the process of programming. Several factors, such as impaired foetal growth, premature birth or postnatal growth of low birth weight infants may be involved, but to which extent is still unclear.

Arteries↗