Neonatal ventricular tachyarrhythmias in medium chain acyl-CoA dehydrogenase deficiency

We describe an unusually severe case of medium chain acyl-CoA dehydrogenase (MCAD) deficiency in a term female neonate, who presented at 12 h of age with lethargy, poor feeding, hypoglycemia and ventricular tachyarrhythmias. While arrhythmias are common in other disorders of fatty acid beta-oxidation, ventricular tachyarrhythmias have rarely been reported with MCAD deficiency in childhood. Since the results of newborn metabolic screening are usually not available within the first 3 days of life, our case highlights the need for health care professionals to be made aware of this early and uncommon but potentially fatal presentation of MCAD deficiency.

The fetus, not the mother, elicits maternal immunologic rejection: lessons from discordant dizygotic twin placentas

AIMS

Our objective was to elucidate the pathogenesis of twin discordance in four dizygotic pregnancies where only one of the twins had IUGR due to chronic villitis.

METHODS

We identified four cases of dizygotic twin placentas over a period of four years with evidence of chronic villitis. There was no clinical or pathologic evidence of TORCH, bacterial infection, preeclampsia or autoimmune disorders. Placentas were weighed, processed for histologic examination and stained with CD45RO (clone UCHL1) mouse monoclonal antibody, which identifies T-cells.

RESULTS

All placentas were dichorionic, with two being fused. Birth weight differences were 29%, 41%, 17% and 10%. Villitis was more marked in the placenta of the twin that weighed less and correlated with the degree of weight discordance. On examining the junction between the fused dichorionic placentas, the chorionic villi from the smaller twin contained numerous T-cells, whereas the villi associated with the less affected twin, showed little to no T-cells.

CONCLUSION

We describe a series of dizygotic twin placentas where the more severe the chronic villitis, the more affected the placenta and fetus. Since the maternal environment was constant for each of these twins, differences in villitis severity appears to be attributable to differences in the ability of each placenta to induce a maternal immune response.

Developmental regulation of NO-mediated VEGF-induced effects in the lung

Vascular endothelial growth factor (VEGF) is known to have a pivotal role in lung development and in a variety of pathologic conditions in the adult lung. Our earlier studies have shown that NO is a critical mediator of VEGF-induced vascular and extravascular effects in the adult murine lung. As significant differences have been reported in the cytokine responses in the adult versus the neonatal lung, we hypothesized that there may be significant differences in VEGF-induced alterations in the developing as opposed to the mature lung. Furthermore, nitric oxide (NO) mediation of these VEGF-induced effects may be developmentally regulated. Using a novel externally regulatable lung-targeted transgenic murine model, we found that VEGF-induced pulmonary hemorrhage was mediated by NO-dependent mechanisms in adults and newborns. VEGF enhanced surfactant production in adults as well as increased surfactant and lung development in newborns, via an NO-independent mechanism. While the enhanced survival in hyperoxia in the adult was partly NO-dependent, there was enhanced hyperoxia-induced lung injury in the newborn. In addition, human amniotic fluid VEGF levels correlated positively with surfactant phospholipids. Tracheal aspirate VEGF levels had an initial spike, followed by a decline, and then a subsequent rise, in human neonates with an outcome of bronchopulmonary dysplasia or death. Our data show that VEGF can have injurious as well as potentially beneficial developmental effects, of which some are NO dependent, others NO independent. This opens up the possibility of selective manipulation of any VEGF-based intervention using NO inhibitors for maximal potential clinical benefit.

Fatal influenza B virus pneumonia in a preterm neonate: case report and review of the literature

Although less common than influenza A, influenza B infections can cause significant mortality and morbidity in children who are immunocomprised and have underlying medical conditions. We report a preterm neonate with fatal influenza B virus pneumonia. This infant presented with signs and symptoms indistinguishable from any other cause of sepsis.

Fetal heart rate accelerations and the risk of cerebral lesions and poor neurodevelopmental outcome in very low birthweight neonates

The risk of intraventricular hemorrhage and periventricular leukomalacia correlates with fetal brain immaturity. Given that the appearance of fetal heart rate (FHR) accelerations is associated with brain maturation, we tested the hypothesis that neonatal cerebral lesions and developmental delay in very low birthweight newborns are associated with absent reactivity of the FHR tracing prior to delivery. We analyzed the FHR tracing of 97 fetuses with birthweight < 1200 g who underwent head ultrasound at day 3 and Bayley Scales of Infant Development testing at age 1 year. We used multivariate analysis to adjust for confounding variables. We found that the absence of two FHR accelerations of 10 beats per minute (bpm) for 10 seconds twice in a 20-minute window 1 hour before delivery was associated with intraventricular hemorrhage and/or periventricular leukomalacia ( P < 0.01) and a significant risk for mental and psychomotor delays by Bayley testing ( P < 0.001). The absence of accelerations of 15 bpm for 15 seconds was not associated with these abnormalities. The absence of FHR accelerations before delivery suggests a greater risk for cerebral injury and developmental delay in the very premature neonate.

Insular carcinoma of the thyroid in an adolescent: a case report and review of the literature

A 15-year-old girl was referred for a thyroid gland mass, which rapidly enlarged in the brief interval between initial evaluation and surgery. Fine needle aspiration of the mass suggested a diagnosis of papillary thyroid carcinoma. Upon pathological examination of this aggressive tumor, an "insular" pattern of tumor was identified. Insular carcinoma of the thyroid gland is unusual in the pediatric age group, however its aggressive nature and prognosis have important management implications for those physicians involved in the care of affected patients. Aggressive surgical debulking, very close observation of the course of disease, and adjunctive radioiodine therapy may all be indicated as were performed in this case. A description of the pathology of this condition, and a review of the clinical experience with insular carcinoma in childhood and adolescence are presented.

Trophoblast differentiation modulates the activity of caspases in primary cultures of term human trophoblasts

Cultured human cytotrophoblasts are more susceptible than syncytiotrophoblasts to hypoxia-induced apoptosis. Caspases are cysteine proteases that cleave cellular components to effect the apoptotic cascade. We hypothesized that cultured cytotrophoblasts exhibit a higher activity of caspases when compared with syncytiotrophoblasts. Using western analysis, we demonstrated that the pro-caspases 3, 6, 8, and 9 are expressed in cytotrophoblasts cultured for 24 h, and also, in trophoblasts cultured 72 h when syncytiotrophoblasts have formed. Importantly, we found significantly higher activity of all four caspases in trophoblasts cultured 24 h compared with cells cultured 72 h. Colchicine and DMSO, which hinder trophoblast differentiation, enhanced the activity of all four caspases in cells cultured 72 h. Conversely, caspase activity was reduced in trophoblasts cultured for 24 h in the presence of epidermal growth factor, which enhances differentiation. This effect was most pronounced on caspase 3 and was attenuated by addition of the tyrosine kinase inhibitor AG1478. We conclude that cytotrophoblasts exhibit a higher activity of caspases 3, 6, 8, and 9 when compared with the more differentiated syncytium. This may account for the higher susceptibility of cytotrophoblasts to hypoxia-induced apoptosis.

Trophoblast apoptosis from pregnancies complicated by fetal growth restriction is associated with enhanced p53 expression

OBJECTIVE

We tested the hypothesis that apoptotic trophoblasts from pregnancies associated with fetal growth restriction caused by preeclampsia or cigarette use exhibit enhanced expression of the proapoptotic proteins p53 and Bax and diminished expression of the antiapoptotic protein Bcl-2.

STUDY DESIGN

Placentas were obtained from women with uncomplicated pregnancies (n = 4) or from women with pregnancies complicated by fetal growth restriction associated with preeclampsia, cigarette use, or both (n = 7). Placental sections were examined by means of hematoxylin and eosin and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) staining, as well as by detection of cytokeratin 18 cleavage products indicative of apoptosis. The expression of p53 was examined by means of Western immunoblotting and immunohistochemistry. The expression of Bax, Bcl-2, Bak, and Bcl-X(L) was analyzed by immunoblotting.

RESULTS

More apoptosis was found in the trophoblast layer of villi from pregnancies complicated by fetal growth restriction than in the trophoblast layer of villi from control pregnancies. The enhanced apoptosis correlated with up-regulation of p53, primarily in cytotrophoblast nuclei. There was no difference between the two groups in expression of the proteins from the Bcl-2 family.

CONCLUSIONS

The expression of p53, but not members of the Bcl-2 family of proteins is up-regulated in human placental villi from pregnancies complicated by fetal growth restriction. We speculate that conditions predisposing to placental hypoxia lead to p53-mediated apoptosis in trophoblasts and thereby contribute to placental dysfunction.

Thromboxane A(2) limits differentiation and enhances apoptosis of cultured human trophoblasts

Prostanoids influence differentiation in diverse cell types. Altered expression of cyclooxygenase and prostaglandins has been implicated in the pathophysiology of placental dysfunction, which results in preeclampsia and fetal growth restriction. We hypothesized that prostanoids modulate differentiation and apoptosis in cultured human trophoblasts. Villous cytotrophoblasts were isolated from term human placentas and cultured in serum-free medium. The level of human chorionic gonadotropin was used as a marker of biochemical differentiation of primary trophoblasts, and syncytia formation was used as a marker of morphologic differentiation. Of the prostanoids tested, we found exposure to thromboxane A(2) hindered both biochemical and morphologic differentiation of cultured trophoblasts. As expected, human chorionic gonadotropin levels in the media were elevated in a concentration-dependent manner in the presence of the thromboxane synthase inhibitor, sodium furegrelate, or the thromboxane A(2) receptor blocker SQ 29,548. Furthermore, thromboxane A(2) enhanced trophoblast apoptosis, determined using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, cell morphology, and a concentration-dependent increase in p53 expression. We conclude that thromboxane A(2) hinders differentiation and enhances apoptosis in cultured trophoblasts from term human placenta. We speculate that thromboxane may contribute to placental dysfunction by restricting differentiation and enhancing apoptosis in human trophoblasts.

Is management of neonatal respiratory distress syndrome feasible in developing countries? Experience from Karachi (Pakistan)

There is a marked paucity of data on the prevalence, management, and outcome of respiratory distress syndrome (RDS) among newborn infants born in developing countries. We reviewed the clinical profile, presentation, mode of therapy, and immediate and 12-month outcomes in 200 consecutive infants with documented RDS admitted to the Neonatal Intensive Care Unit at Aga Khan University Hospital, Karachi. One hundred fifty-six (79%) of these infants required assisted ventilation. Infants requiring ventilatory assistance had higher rates of maternal antenatal complications, were more frequently asphyxiated at birth, and were hypothermic on admission. The overall mortality was 39%, and a further 3 infants died in early infancy after discharge. The mean duration of hospitalization for ventilated survivors (n = 122) was 24.6 +/- 21.1 days, with an average cost of therapy per survivor of Rs 50,067 (US $1,391). While our experience from Karachi indicates that it is possible to provide successful respiratory support at comparatively low cost to newborn infants weighing >1,000 g with severe RDS, there is considerable room for improvement in outcome with the use of preventive measures such as antenatal steroids, appropriate intrapartal care, and attention to early stabilization after birth.

Early-onset neonatal sepsis in Pakistan: a case control study of risk factors in a birth cohort

We prospectively evaluated risk factors for early-onset neonatal (EON) sepsis in a case-control study among inborn patients at the Aga Khan University Medical Centre in Karachi between 1990-1993. A total of 38 cases with blood culture proven bacterial sepsis were identified within 72 hr of birth (prevalence 5.6 of 1000 live births) and matched with two consecutive gender matched births with no complications. The most common isolates were Staphylococcus aureus (18%), group B Streptococci (13%), and Klebsiella pneumoniae (13%). Univariate analysis of maternal risk factors revealed a significant association between maternal urinary tract infection (UTI) (odds ratio [OR]20, 95% confidence interval [CI]2.4-166.9), maternal pyrexia (P < 0.0001), vaginal discharge (P < 0.05), vaginal examinations during labor (P = 0.03), and EON sepsis. The infected newborns also had significantly lower apgar scores at birth (P < 0.0001) and a significantly greater number were intubated at birth (Fisher's exact test P = 0.04). Infected newborn infants were transferred out of the labor room earlier than noninfected controls and significantly fewer received exclusive breastfeeds (OR 0.33, 95% CI 0.1-0.8). Our data suggest the possibility that both vertical transmission from the mother as well as postnatal acquisition of infection from the environment may be of importance in the pathogenesis of EON sepsis in Karachi. Preventive measures should focus at recognition of high-risk infants, strict asepsis during labor, and early institution of exclusive breastfeeding.

Profile and outcome of the respiratory distress syndrome among newborns in Karachi: risk factors for mortality

Although survival data on very low birth weight (VLBW) infants from developing countries indicates that mortality rates are high, there is considerable disagreement on the relative contribution of respiratory distress syndrome to neonatal morbidity and mortality. With improving facilities for newborn care, it is now possible to provide basic respiratory support to some babies with RDS in selected centres. We prospectively evaluated the profile and outcome of newborn infants with respiratory distress admitted to the newborn services at Aga Khan University Hospital in Karachi. The overall mortality for newborns with documented RDS was 81/200 (41 per cent), and was highest (70 per cent) for babies weighing < 1000 g at birth. Univariate and logistic regression analysis of factors significantly associated with high risk of dying despite respiratory support, included low apgar score at one minute (P = 0.003), admission AaDO2 value > 400 (P = 0.001), development of acute renal failure (Relative risk 6.2, 95 per cent confidence interval 1.0-40.0), intraventricular haemorrhage (RR 2.6, 95 per cent CI 1.3-5.2) and pneumothorax (RR 3.7, 95 per cent CI 1.8-7.7). Our data highlight the importance of the immediate postnatal period in infants with RDS and suggest that close attention to early stabilization of VLBW infants with RDS, may further reduce the mortality associated with this disorder.

Neonatal sepsis in Karachi: factors determining outcome and mortality

Neonatal sepsis is a major cause of morbidity and mortality among newborns in the developing world. In a consecutive cohort of 292 infants with culture proven neonatal sepsis, the mortality was 68 (22 per cent). We analysed the association of predisposing factors, clinical, and laboratory characteristics of the infected newborns with mortality by univariate methods and logistic regression analysis. Comparatively higher rates of mortality were seen among home-delivered newborn infants and those referred from other maternity facilities. The mortality was significantly higher among infants weighing < 1500 g and those with birth asphyxia (P < 0.05). The overall mortality was higher for gram negative infections and the highest case fatality rates were seen in infections with Pseudomonas species (52 per cent) and Streptococcus pneumoniae (100 per cent). Several clinical features suggestive of septicaemic shock and metabolic derangement were associated with significantly increase risk of death. Of these, the logistic regression model identified hypotensive shock (odds ratio 3.6) and acute renal failure (odds ratio 11.2) as significant factors associated with risk of death. Our data suggest that delayed presentation and recognition of neonatal sepsis is associated with rapid development of multiorgan dysfunction and increased risk of mortality.

Neonatal respiratory distress syndrome in Karachi: some epidemiological considerations

Although respiratory distress syndrome (RDS) is a leading cause of neonatal morbidity and mortality in the west, there are few data on the prevalence and spectrum of RDS from developing countries. Available evidence suggests that the disorder may be less common than the overall 1% incidence reported from developed countries. In a prospective study of the prevalence of RDS in a consecutive 10,134 births at the Aga Khan University Hospital, we documented the disorder in 127 (1.2% births), with a prevalence of 12.8% among low birthweight infants. The overall mortality for this group was 39%, with the highest mortality rate (68%) among newborn infants < or = 1000 g birthweight. Our data from a large and relatively well-nourished hospital-born population in Karachi suggest that RDS is a significant cause of morbidity and mortality in preterm infants with a similar prevalence rate to western figures.

Transcutaneous bilirubinometry in Pakistani newborns: a preliminary report

Neonatal hyperbilirubinemia is a frequently encountered problem in the neonatal period and carries a potential risk of encephalopathy. Early detection and quantification is important, and transcutaneous bilirubinometry (TcB) has been recommended as a non-invasive method for rapid screening. We prospectively compared the efficacy of TcB in 65 normal Pakistani jaundiced newborns undergoing simultaneous serum bilirubin measurements. Although the correlation between the two methods was significant (r = 0.66, P less than 0.01), the scatter was wide and the specificity only 53%. Although the technique offers the potential for non-invasive early screening of neonatal hyperbilirubinemia, it requires further validation in a larger study in our population.