Patent ductus arteriosus closure using the new Amplatzer Duct Occluder. Preliminary results and review of the literature

BACKGROUND

Patent ductus arteriosus (PDA) is the second most common congenital heart disease. A large number of surgical and transcatheter techniques for the interruption or closure of PDA has been reported. The aim of this study was to assess the immediate and short-term results of transcatheter closure of PDA using the new, self-expandable, self-centering, and repositionable Amplatzer Duct Occluder device.

METHODS

We attempted occlusion of PDA with the Amplatzer Duct Occluder in seven consecutive patients, one child and six adults, four females and three males, between September 1999 and January 30th 2000. All PDAs but one were approached from the femoral venous site; the Amplatzer Duct Occluder size was selected in order to be 2 mm larger than the duct's diameter at its narrowest site and the mean PDA diameter was 5.4+/-2.5 mm (range 3-9). All patients underwent physical examination, chest X-ray and echocardiography within 48 hours and on first and third month after PDA occlusion.

RESULTS

Four patients had a megaphone type (type A), and three had an elongated, conical type (type E) PDA. Four patients had immediate, complete angiographic closure of the ductus 10 minutes after the procedure, one had a trace shunt and two had small shunts which all disappeared within 48 hours. The average fluoroscopy time and procedural time were 34.4+/-10.6 min (range 21-50) and 105+/-38.9 min (range 75-190) respectively. There were no complications at follow-up.

CONCLUSIONS

Transcatheter closure of PDA using the new Amplatzer Duct Occluder is an easy and effective technique. Moreover it is safe even in the presence of wide PDAs.

Total laryngectomy: pre- and intrasurgical variables of infection risk

Postoperative infection has influence on costs, quality of life, and outcome of the disease. It is suspected that post-total laryngectomy infections have increased in frequency and seriousness, because of the failure of the preservation protocol or the previous radiotherapy, making rescue surgery necessary. The objective of this study was to develop a predictive model of infection based on the pre- and intrasurgical variables considered risky. One hundred fifty five patients with E III-IV laryngeal cancer, with 24.8:1 male to female ratio (mean age, 58 years) who underwent total laryngectomy were evaluated for uni- and multivariate analysis of age, sex, histological grade, primary or recurrent disease, tobacco, alcohol, diabetes, tuberculosis/chronic emphysema, red and white cell counts, erythrosedimentation rate (ESR), albumin, chemotherapy, neck radiotherapy and/or previous surgery, confinement days, type and time of surgery, which were factors in the infection event. A predictive model of infection was developed and included albuminemia (<3.5 g%), >1 liter of alcohol daily, and exclusive surgery of the primary. The sensitivity was 90.5% and the specificity 68%. The variance reached 29.6%. The causes of infection were multiple, having analyzed only 30% of them. However, the resulting model was classified correctly in 83.2% of cases. A careful preoperative assessment, an adjusted planning of the surgery, an appropriate use of antibiotics, and a meticulous operative technique are needed to prevent infection.

[Sentinel lymphnode: surgical standard in breast cancer]

Evaluation of the sentinel lymph node (SLN) is capable of avoiding dissection in a high percentage of node negative patients (> 90). It is essential that "useless" treatment not be performed as the negative collateral effects are not justifiable and furthermore present financial laws do not reimburse dissections carried out in the absence of node disease. The intraoperative evaluation of the SL is an extremely expensive procedure, due both to the personnel required and to the time necessary for the patient to remain in the operating room awaiting histology results. In fact, it is far easier to retrieve the SLN in day hospital and to examine the specimen on fixed material and not frozen. Twenty three cases of deferred SLN were evaluated, the results of which were highly reliable because of these, only 3 dissections were performed after an average of 4 days from biopsy. As SL evaluation does not increase the "curability" of the disease but only reduces any eventual complications, we believe it should be restricted to extremely selected and specialistic institutions due to the great economical and organizational cost involved.

Enterotoxicity and cytotoxicity of Vibrio parahaemolyticus thermostable direct hemolysin in in vitro systems

Vibrio parahaemolyticus is a marine bacterium known to be a common cause of seafood gastroenteritis worldwide. The thermostable direct hemolysin (TDH) has been proposed to be a major virulence factor of V. parahaemolyticus. TDH causes intestinal fluid secretion as well as cytotoxicity in a variety of cell types. In this study, we investigated the interplay between the hemolysin's enterotoxic and cytotoxic effects by using both human and rat cell monolayers. As revealed by microspectrofluorimetry, the toxin causes a dose-dependent increase in intracellular free calcium in both Caco-2 and IEC-6 cells. This effect was reversible only when low toxin concentrations were tested. The TDH-activated ion influx pathway is not selective for calcium but admits ions such sodium and manganese as well. Furthermore, in the same range of concentration, the hemolysin triggers a calcium-dependent chloride secretion. At high concentrations, TDH induces a dose-dependent but calcium-independent cell death as assessed by functional, biochemical, and morphological assays.

Ischaemic preconditioning of the vasculature: an overlooked phenomenon for protecting the heart?

Exposing the heart to brief episodes of ischaemia protects the myocardium and vascular endothelial cells against functional damage and cell death caused by subsequent prolonged ischaemia. Elucidation of the mechanisms that are involved in this phenomenon known as 'ischaemic preconditioning' and identification of drugs that mimic the protective response have the potential to improve the prognosis of myocardial infarction and other cardiac syndromes dramatically. This article focuses on recent findings on the effects of ischaemic preconditioning of the coronary vasculature, which highlight the endothelium as an important target for a successful therapeutic approach to myocardial ischaemia-reperfusion injury.

Increased urinary excretion of collagen crosslinks in type 1 diabetic children in the first 5 years of disease

To analyze possible early abnormalities in bone resorption in type 1 diabetes mellitus the urinary excretion of the collagen crosslinks pyridinoline and deoxypyridinoline was evaluated by immunoassay in 26 prepubertal diabetic patients (mean age 7.8 +/- 1.6 years, mean duration 3.0 +/- 1.1 years) and 46 healthy children (age 8.3 +/- 1.3 years). Relationships with growth parameters (height-standard deviation score, body mass index and height velocity during the year preceding the study) and metabolic control were sought. Longitudinal and ponderal growth was normal in diabetic children. Urinary collagen crosslink excretion was 88.4 +/- 25 nmol/mmol creatinine (median 86, range 44-146) in diabetic patients and 65.6 +/- 19 nmol/mmol creatinine (median 61, range 32-108) in controls (p = 0. 0002). It was positively influenced by diabetic status (beta = 20.5) and negatively by age (beta = -6.41), controlling by sex and BMI (p = 0.0001). A positive correlation was found between collagen crosslinks and blood glucose (r = 0.48, p = 0.01) or HbA1c levels (r = 0.44, p = 0.02) evaluated at the time of the study, while no significant correlation was found with the mean HbA1c values assessed in the last year or throughout the whole duration of diabetes. Collagen crosslink excretion was significantly increased in patients who presented worsening of their metabolic control in the last 3 months. No relationship was found with the duration of disease or growth parameters. In conclusion, the elevated urinary excretion of collagen crosslinks in diabetic children indicates that bone resorption may be disturbed. Poor metabolic control influences the increased rate of bone resorption and may expose growing diabetic patients to a risk of bone loss.

Nitric oxide and endothelin-1 in coronary and pulmonary circulation

Since the discovery of the vasorelaxant properties of nitric oxide and the vasoconstrictor effect of endothelin-1, there have been many studies of the distribution and functional significance of these agents in various vascular beds. In the coronary and pulmonary circulation nitric oxide and endothelin-1 actions have been largely investigated in terms of an imbalance between the opposing effects of these vasoactive agents leading to pathophysiological conditions. This article review functional and immunocytochemical studies with emphasis on the ultrastructural localization of nitric oxide synthase and endothelin-1 in the coronary and pulmonary vascular beds. Localization of nitric oxide synthase (type III or I or II) has been shown in endothelial cells, smooth muscle, and perivascular nerves of the coronary and pulmonary vascular beds and in the neurons, nerve fibers, and the small granule-containing cells within cardiac ganglia. Endothelin-1 was mainly localized in subpopulations of coronary and pulmonary endothelial cells. These immunocytochemical studies provide information about the sources of nitric oxide and endothelin-1 that contribute to the vasomotor control of cardiac and pulmonary circulation under normal and pathophysiological conditions.

Regulation of vascular tone by UTP and UDP in isolated rat intrapulmonary arteries

Vasoconstrictor and vasodilator responses of isolated rat intrapulmonary arteries to the pyrimidine nucleotides UTP and UDP were evaluated and compared with vascular responses to ATP and its analogues. UTP and UDP (1-500 microM) were equipotent in inducing concentration-dependent vasoconstriction, unaffected by the P2 receptor antagonists suramin (100 microM) and Reactive blue 2 (50 microM); ATP (10-500 microM) produced weaker vasoconstriction. UTP and UDP lacked vasodilator activity, while ATP and its analogue 2-methylthio ATP evoked endothelium-dependent vasodilatation. These results indicate that UTP and UDP evoke vasoconstriction of rat intrapulmonary arteries whereas ATP is predominantly a vasodilator at the same arteries. Furthermore, the pharmacological profile of the native UTP/UDP receptor differs from that of the known P2Y2, P2Y4 and P2Y6 recombinant receptors for pyrimidine nucleotides.

Characterisation of subtypes of the P2X and P2Y families of ATP receptors in the foetal human heart

ATP exerts a variety of actions within the myocardium, including the regulation of coronary vascular tone and modulation of the autonomic control of the heart. In order to characterise the ATP receptor subtypes involved in these effects, degenerate oligonucleotides were used to clone receptors of both P2X and P2Y families from the human foetal heart. About 1 ng of "Quick-Clone cDNA" from foetal human heart was subjected to amplification with two pairs of degenerate oligonucleotides designed to amplify subtypes of the P2X and P2Y receptor families by means of PCR reactions. The sequence analysis of 34 and 29 clones of the P2X and P2Y receptor families, respectively, demonstrated that P2X1, P2X3 and P2X4 subtypes are present in the human foetal heart together with P2Y6, P2Y2 and P2Y4 receptors. P2X1 and P2Y4 receptor subtypes were here characterised for the first time in the human foetal heart. The present study provides the first molecular characterisation of ATP receptors in the foetal human heart. The results show that many P2 receptor subtypes are expressed in the foetal human heart, perhaps contributing to developmental processes as well as to the activity of the foetal heart.

In vivo and in vitro efficacy of octreotide for treatment of enteric cryptosporidiosis

Previous evidence suggested a role of enterotoxin in the pathophysiology of cryptosporidiosis. If so, antisecretory drugs should be effective in reducing diarrhea. We evaluated the in vivo and in vitro efficacy of octreotide, which possesses antisecretory effects, for cryptosporidial diarrhea. Two children with severe cryptosporidial diarrhea were treated with octreotide. The volume modifications and chemical composition of stools were determined. Fecal supernatant was added to Caco-2 cell monolayers mounted in Ussing chambers with or without serosal octreotide and electrical parameters were monitored. Octreotide was effective in reducing the stool volume and fecal Na+ concentration. Fecal supernatant induced an enterotoxin-like increase in transepithelial potential difference. Octreotide induced a dose-dependent decrease in basal potential difference, consistent with an absorptive effect. In cells pretreated with octreotide, fecal supernatant induced an increase in the potential difference, whose magnitude and duration were significantly reduced compared to untreated cells. These results provide in vivo and in vitro evidence for the secretory nature of cryptosporidial diarrhea and for the efficacy of octreotide through a direct interaction with the enterocyte.

Onset of obesity in children through the recall of parents: relationship to parental obesity and life events

Obesity is a multifactorial disease due to the influence of both genetic and environmental factors. Parents of 886 obese patients (427 boys and 459 girls, aged 1-18 years) were investigated by means of a questionnaire in order to study the factors associated with the onset of obesity in children and the relationship to genetic background. At presentation obese patients had a very high mean ideal body weight percent (IBW%) (154 +/- 19%, median 152%, range 120-246). A significantly higher mean IBW% was found in children of obese parents (one obese parent: 158 +/- 21%, median 156%, range 120-246; two obese parents 160 +/- 18%, median 158%, range 123-226) in comparison to children of normal weight parents (150 +/- 18%; median 147%, range 120-235; p = 0.0001 for children of one or two obese parents versus children of normal weight parents). Parents of 414 subjects (46.7%) (Group A) answered that obesity had always been present. The remaining 472 parents (53.3%) (Group B) stated that obesity had had a beginning at a mean age of 5.3 +/- 2.6 years (median 5.0 years, range 1.0-17.0). No difference was found in age at presentation, sex distribution, birth weight and number of obese parents between the two groups. Parents in Group B recalled an event associated with obesity onset in 197 cases (health event: 119 answers, psycho-social event: 78 answers). Genetic background did not influence this pattern of feedback. In conclusion, parents of obese subjects seek medical advice when obesity is severe. Pediatricians should exert strict surveillance on weight from a very young age. The recall in 22% patients of health or psychosocial events at the onset of obesity emphasizes that medical counselling is important when the occurrence of particular events in life may cause erroneous eating habits.

Age-related changes in purinergic and adrenergic components of sympathetic neurotransmission in guinea-pig seminal vesicles

1. Purinergic and adrenergic components of sympathetic neurotransmission and contractile responses to exogenous alpha,beta-methylene ATP and noradrenaline have been investigated in the seminal vesicles of 1-day (new-born), 2-weeks (young), 12-weeks (adult) and 2-years old (aged) guinea-pigs. 2. In seminal vesicles of new-born guinea-pigs electrical field stimulation (EFS; 80 V, 0.5 ms for 30 s, 2-32 Hz) evoked tonic frequency-related contractions. In 2-weeks old guinea-pigs the tonic contraction masked an initial phasic component of the neurogenic responses, whereas in 12-weeks and 2-years old guinea-pigs, neurogenic responses were biphasic, a phasic response being followed by a tonic contraction. In all experimental groups, prazosin (10(-6) M) blocked the tonic contraction while desensitization of P2X receptors by alpha,beta-methylene ATP (10(-4) M) abolished the phasic responses. 3. The phasic purinergic component of the neurogenic response was significantly higher in 12-weeks and 2-years old animals, compared with 2-weeks old guinea-pigs. At 32 Hz phasic contractions were (mN mg(-1) tissue): 0.047+/-0.012, 0.018+/-0.040 and 0.147+/-0.026 in 2-weeks, 12-weeks and 2-years old guinea-pigs, respectively. In contrast, the tonic adrenergic component of the neurogenic contraction significantly declined at 12-weeks and 2-years compared with 2-weeks old guinea-pigs. 4. Contractile responses (mN mg(-1) tissue) to the highest concentration of alpha,beta-methylene ATP tested were significantly higher in 2-weeks (0.248+/-0.022) than in 1-day old animals (0.113+/-0.012) and decreased in 12-weeks (0.163+/-0.016) and 2-years old guinea-pigs (0.200+/-0.008). The pD2 values for the purinoceptor agonist were also significantly lower in adult (4.74+/-0.20) and aged guinea-pigs (5.22+/-0.08) compared with 2-weeks old animals (5.91+/-0.27). Conversely, responses to the highest concentration of noradrenaline gradually decreased with age, without significant changes in the pD2 values. Contractile responses to KCl (240 mM) did not differ significantly between the experimental groups. 5. These results demonstrate age-related changes in purinergic and adrenergic components of sympathetic neurotransmission in the guinea-pig seminal vesicles. The purinergic component is absent in new-born animals and it appears fully developed in adult and old guinea-pigs, while the adrenergic component decreases with age. Pre- and postjunctional mechanisms contributing to the age-related changes of sympathetic neurotransmission are discussed.

Enteric cryptosporidiosis in pediatric HIV infection

BACKGROUND

Enteric cryptosporidiosis is a frequent problem in adults with human immunodeficiency virus (HIV) infection, but little is known of its features in children. The aim of this study was to investigate the incidence and the clinical features of cryptosporidiosis in HIV-infected children.

METHODS

Thirty-five children with symptomatic HIV infection were screened every 2 months, and in case of diarrhea, for the presence of Cryptosporidium. Intestinal function tests were performed, and the fecal osmotic gap was measured in children with cryptosporidiosis.

RESULTS

Seventy episodes of diarrhea occurred in 16 children in a median period of 17 months. Cryptosporidium was detected in five cases, all with full-blown acquired immunodeficiency syndrome. Cryptosporidiosis was significantly more protracted than any other form of diarrhea and was associated with dehydration and severe weight loss. Intestinal function was not modified during cryptosporidiosis. Osmotic gap values were consistent with secretory rather than osmotic diarrhea. In four cases, recovery was observed without specific treatment.

CONCLUSIONS

Enteric cryptosporidiosis is a severe problem in advanced stages of HIV infection. It does not induce intestinal malabsorption. It induces diarrhea of secretory type. Recovery may be observed independently of therapy.

Sympathetic neurotransmission in isolated rat atria after sensory-motor denervation by neonatal treatment with capsaicin

Long-term interactions between sympathetic and sensory-motor nerves have been shown in several tissues. Previous investigations in this laboratory have demonstrated an increase in cardiac sensory-motor innervation after neonatal sympathectomy by guanethidine and an increase of perivascular sympathetic neurotransmission after neonatal treatment by capsaicin. The present study evaluated the effects of sensory-motor denervation on sympathetic neurotransmission in the heart. Newborn rats were injected with capsaicin or its vehicle (Tween 80). Sympathetic neurotransmission was studied in isolated atria driven at a constant rate (4 Hz) by measuring cardiac responses to electrical field stimulation, in the presence of atropine 1 microM. Inotropism of tyramine, norepinephrine and calcitonin gene-related peptide was also tested. Neonatal capsaicin treatment did not affect cardiac responses to trains of an increasing number (2-32) of field pulses. Moreover, inotropic responses to tyramine did not differ between control, capsaicin- and Tween 80-treated preparations. Neither maximal effect nor pD2 values were significantly different between the groups. Similarly, the inotropism of calcitonin gene-related peptide was comparable in all groups of atrial preparations. In marked contrast to earlier papers on blood vessels, this study shows a lack of effect of sensory-motor denervation by neonatal capsaicin treatment on cardiac sympathetic neurotransmission. The different neuronal plasticity of vascular and cardiac sensory innervation will be discussed. The present results also indicate that capsaicin-induced sensory-motor denervation is not associated with changes in cardiac responsiveness to calcitonin gene-related peptide.

Liver involvement in obese children. Ultrasonography and liver enzyme levels at diagnosis and during follow-up in an Italian population

Our aim was to evaluate incidence and risk factors of liver involvement in obese Italian children as assessed by both ultrasonographic and biochemical parameters. In seventy-five consecutive obese children (age 9.5 +/- 2.9 years, males/females 41/34), serum levels of enzymes and ultrasonography of the liver were evaluated. Tests were repeated one, three, and six months after starting a moderate hypocaloric diet and an exercise program. Three obese children who were found to have chronic viral hepatitis were excluded from the study. Thirty-eight of 72 (53%) obese children had an ultrasonographic image of bright liver consistent with liver steatosis. The latter was severe in nine children, moderate in 16, and mild in 13. Eighteen obese children (25%) had elevated transaminase levels. Bright liver and hypertransaminasemia were not due to any of the most common causes of liver disease. Both were rapidly responsive to loss of weight, confirming that liver involvement was secondary to obesity and that steatosis or steatohepatitis rather than fibrosis were involved. Obesity duration not more than three years (odds ratio = 4.77), a higher degree of obesity (odds ratio = 2.09), and hypertransaminasemia (odds ratio = 2.15) appeared as important predictive factors of liver involvement at ultrasonography. Incidence of liver involvement assessed by means of ultrasonography is significantly higher than that revealed by measurement of serum liver enzymes. A short duration of obesity emerged as a potentially new risk factor of liver involvement in the pediatric obese population and needs to be confirmed in future studies.

Liver involvement in obese children. Ultrasonography and liver enzyme levels at diagnosis and during follow-up in an Italian population

Our aim was to evaluate incidence and risk factors of liver involvement in obese Italian children as assessed by both ultrasonographic and biochemical parameters. In seventy-five consecutive obese children (age 9.5 +/- 2.9 years, males/females 41/34), serum levels of enzymes and ultrasonography of the liver were evaluated. Tests were repeated one, three, and six months after starting a moderate hypocaloric diet and an exercise program. Three obese children who were found to have chronic viral hepatitis were excluded from the study. Thirty-eight of 72 (53%) obese children had an ultrasonographic image of bright liver consistent with liver steatosis. The latter was severe in nine children, moderate in 16, and mild in 13. Eighteen obese children (25%) had elevated transaminase levels. Bright liver and hypertransaminasemia were not due to any of the most common causes of liver disease. Both were rapidly responsive to loss of weight, confirming that liver involvement was secondary to obesity and that steatosis or steatohepatitis rather than fibrosis were involved. Obesity duration not more than three years (odds ratio = 4.77), a higher degree of obesity (odds ratio = 2.09), and hypertransaminasemia (odds ratio = 2.15) appeared as important predictive factors of liver involvement at ultrasonography. Incidence of liver involvement assessed by means of ultrasonography is significantly higher than that revealed by measurement of serum liver enzymes. A short duration of obesity emerged as a potentially new risk factor of liver involvement in the pediatric obese population and needs to be confirmed in future studies.

Immunoreactivity for nitric oxide synthase and endothelin in the coronary and basilar arteries of renal hypertensive rats

The ultrastructural localization of immunoreactivity to nitric oxide synthase (type-III and type-II) and endothelin-1 was examined by using pre-embedding peroxidase-antiperoxidase techniques in the coronary and cerebral basilar arteries in renal hypertensive rats. Renal hypertension was produced by excision of the right kidney and clipping of the left renal artery. Controls were normotensive sham-operated rats (right surgical nephrectomy; a clip inserted near the left renal artery). Both in controls and hypertensive rats, immunoreactivities for nitric oxide synthase-III and endothelin-1 were localized within subpopulations of endothelial cells. In addition, signs of translocation of nitric oxide synthase-III were noted from the cytoplasm to the Golgi complex in endothelial cells of the basilar artery of hypertensive animals. Neither controls nor hypertensive rats showed immunoreactivity for nitric oxide synthase-II. Preparations of the right coronary artery from hypertensive rats displayed fewer endothelial cells positive to nitric oxide synthase-III than in controls, although there were no significant changes in the distribution of endothelin-1-positive endothelial cells in the coronary artery of hypertensive rats. In contrast, the basilar artery from hypertensive rats displayed no changes in the percentage of endothelial cells immuno-positive either for nitric oxide synthase-III or for endothelin-1. In consequence, the ratio of nitric oxide synthase-III:endothelin-1 was reduced in the coronary but not in the basilar artery. Therefore, the nitric oxide/endothelin-1 system appears to play different roles in the coronary and cerebral circulations during renal hypertension.

Calcitonin gene-related peptide (CGRP)-evoked inotropism during hyper- and hypo-sensory-motor innervation in rat atria

1. Positive inotropic responses to calcitonin gene-related peptide (CGRP) were evaluated in atria isolated from in vivo rat models of hyper-sensory-motor innervation (following neonatal guanethidine treatment) and hypo-sensory-motor innervation (following neonatal capsaicin treatment), to explore the hypothesis that functional responsiveness of atrial myocardium to CGRP may correlate with tissue levels of the sensory-motor neurotransmitters. Comparative of inotropic responses to CGRP following in vitro treatment of atria with guanethidine was also performed. 2. Following long-term guanethidine treatment, positive inotropic responses to CGRP were significantly attenuated, while supersensitivity to the sympathetic transmitter noradrenaline was shown. Maximal inotropic responses to CGRP (30 nM) were 214.0 +/- 28.1 (n = 8) and 146.8 +/- 21.7 mg (n = 8; P < 0.01) increase of the basal contractile tension in control and treated preparations, respectively. The pD2 values for noradrenaline were 6.71 +/- 0.12 (n = 8) and 7.26 +/- 0.13 (n = 6; P < 0.01) in control and treated atria, respectively. Acute application of guanethidine in vitro did not modify the positive inotropism by CGRP or the beta-adrenoceptor agonist isoprenaline. 3. Sensory-motor hypoinnervation following chronic treatment with capsaicin did not affect the inotropic responses to CGRP. Neither guanethidine nor capsaicin treatment affected the contractile apparatus of myocytes, as demonstrated by similar basal contractile tension as well as calcium-evoked inotropic responses in control and treated preparations. 4. In summary, increased sensory-motor innervation, following long-term sympathectomy with guanethidine, resulted in attenuation of the inotropic responses of the rat atrium to CGRP, while no changes in the inotropic responses were seen following sensory-motor denervation with capsaicin. Down-regulation of CGRP receptors or altered post-receptor signalling may be involved in the reduced responsiveness to CGRP.

Amorphous silicon waveguides and light modulators for integrated photonics realized by low-temperature plasma-enhanced chemical-vapor deposition

A new amorphous silicon waveguide is realized by use of amorphous silicon carbon as cladding material. The structure is characterized both experimentally and theoretically, and its application for optical interconnections in photonic integrated circuits on silicon motherboards is proposed. The fabrication process is based on low-temperature (220 degrees C) plasma-enhanced chemical-vapor deposition and is compatible with standard microelectronic processes. Propagation losses of 1.8 dB/cm have been measured at the fiber-optic wavelength of 1.3 microm. A strong thermo-optic coefficient has been measured in this material at this wavelength and exploited for the realization of a light-intensity modulator based on a Fabry-Perot interferometer that is tunable by temperature.

Human serum immunoglobulin counteracts rotaviral infection in Caco-2 cells

Oral administration of human serum immunoglobulin reduces the duration of diarrhea and of rotaviral excretion in children. To investigate the in vitro effects of immunoglobulin on virus-enterocyte interaction, Caco-2 cells were infected with Rotavirus strain SA11. Immunoglobulin was added prior to and at various times postinfection. Indirect immunofluorescence was performed with an antibody against VP-6 rotaviral antigen. Cell viability and monolayer transepithelial electrical resistance (TEER) were monitored. Immunofluorescence showed a perinuclear distribution in 90% of cells. Rotavirus infection induced a progressive decrease in TEER and a parallel reduction in cell viability, depending on viral load. Preincubation of the virus with immunoglobulin prevented cell infection as judged by immunofluorescence. Immunoglobulin addition to infected cells partially prevented the decrease in TEER and induced a later shift of TEER toward increasing values, suggesting restoration of monolayer's integrity. The efficacy of immunoglobulin depended on its concentration and on the time of its addition. These results indicate that immunoglobulin is effective in preventing infection and in reducing cell damage, through a direct anti-Rotavirus action and may indicate that immunoglobulin should be administered in the early phase of diarrhea, to reduce the severity of Rotavirus infection.

[Modified technique for dilatation of pulmonary valve stenosis (nearly atresia) in a neonate]

A modified technique for pulmonary valvuloplasty is described in a 1-day-old newborn with near pulmonary atresia. A transumbilical venous approach and a complete set of devices for coronary angioplasty were utilized; the principal technical innovation was the use of a 7 French right coronary artery guiding catheter. This allowed a firm support to advance the first balloon catheter (a 3.5 coronary angioplasty catheter) through the pulmonary valve, maintaining the guidewire in a stable position in the descending aorta. The dilation was easily completed with progressively larger balloons. The total procedure time was 82' (fluroscopy time 20'), significantly shorter than the previous personal experience and the data from the literature.