Double urethral obstruction in a neonate - a case report

Posterior urethral valves are the most common cause of lower urinary tract obstruction in a male child, generally occurring as an isolated anomaly. Congenital anterior urethral diverticulum, although less common, can also cause urethral obstruction. We report a rare combination of the two anomalies in which the proximal, more severe anomaly prevented the initial expression of the other.

Anorectal malformations and their impact on survival

OBJECTIVE

To evaluate the incidence, types and the effect on outcome of associated anomalies in neonates with anorectal malformations (ARM).

METHODS

This retrospective study was carried out on all neonates with ARM admitted to the neonatal surgical intensive care unit (NSICU) from 1998 through 2003.

RESULTS

Of the 754 neonates admitted to the NSICU during the study period of 6 years, there were 124 (16.4%) neonates with anorectal malformations. Of these 110 were included in the study. 73 % were male and 27% female. 86% of these were high ARM (HARM) while only 14% were low ARM (LARM). Associated anomalies were seen in 68% of patients. The incidence was 72% for HARM and 50% for LARM. The major associated anomalies consisted of esophageal (13%), gastrointestinal (GIT) (11%), genitourinary (GUT) (32%), skeletal (26%), cardiac (33%) and miscellaneous 26%. The overall survival rate was 84% (82% for HARM and 94% for LARM). The survival among those with associated esophageal anomalies was 43%, GIT 67%, GUT 80%, cardiac 61%, skeletal 76% and miscellaneous 79% respectively. This difference in survival was significant only for those with esophageal (p=0.004) and cardiac anomalies (p=0.0026). The survival rates among those with one, two or more than two organ systems involved with associated anomalies were 88%, 82% and 58% respectively. This difference was significant only for more than two organ systems involvement (p=0.003).

CONCLUSION

Associated anomalies are common in neonates with ARM, the incidence being similar for HARM and LARM. The survival depends upon the number and severity of associated anomalies both in patients with LARM and HARM. Neonates with more number of organ systems involved have a poorer survival specially when associated with esophageal and cardiac anomalies. All neonates with ARM merit a meticulous search for associated anomalies so that the management can be tailored for each baby.

Lumbotomy approach for upper urological tract surgery in children--an analysis of 68 consecutive lumbotomies

OBJECTIVES

To comprehensively analyse the results of upper urological tract surgery performed using a lumbotomy approach in the paediatric age group.

METHODS

68 consecutive patients underwent upper urological tract surgery during the last 5 years in our surgical unit. In all of these patients, a lumbotomy approach was used with a transverse skin incision. The hospital charts were reviewed for age, sex, diagnosis, type of surgery, intra-operative problems, duration of surgery, time to oral feeds, postoperative pain, length of hospitalisation and complications.

RESULTS

Age range was 1 month to 12 years with a mean of 66 months. There were 47 boys and 16 girls. Surgeries performed were: pyeloplasty, pyelolithotomy, nephroureterectomy, ureterostomy and heminephrectomy. No intraoperative problems were encountered and the mean duration of surgery was 64.68 minutes. All patients resumed full oral feeds within 24 hours of surgery and postoperative pain was minimal. The mean duration of hospital stay was 6.16 days. No incision-related complications were seen.

CONCLUSIONS

Lumbotomy incision is a safe, easy and effective approach for upper urological tract surgery in children.

Interleukin (IL)-1, IL-6, and IL-8 predict mucosal toxicity of vaginal microbicidal contraceptives

Inflammation of the female reproductive tract increases susceptibility to HIV-1 and other viral infections and, thus, it becomes a serious liability for vaginal products. Excessive release of proinflammatory cytokines may alter the mucosal balance between tissue destruction and repair and be linked to enhanced penetration and replication of viral pathogens upon chemical insult. The present study evaluates four surface-active microbicide candidates, nonoxynol-9 (N-9), benzalkonium chloride (BZK), sodium dodecyl sulfate, and sodium monolaurate for their activity against human sperm and HIV, and their capacity to induce an inflammatory response on human vaginal epithelial cells and by the rabbit vaginal mucosa. Spermicidal and virucidal evaluations ranked N-9 as the most potent compound but were unable to predict the impact of the compounds on vaginal cell viability. Interleukin (IL)-1 release in vitro reflected their cytotoxicity profiles more accurately. Furthermore, IL-1 concentrations in vaginal washings correlated with cumulative mucosal irritation scores after single and multiple applications (P < 0.01), showing BZK as the most damaging agent for the vaginal mucosa. BZK induced rapid cell death, IL-1 release, and IL-6 secretion. The other compounds required either more prolonged or repeated contact with the vaginal epithelium to induce a significant inflammatory reaction. Increased IL-8 levels after multiple applications in vivo identified compounds with the highest cumulative mucosal toxicity (P < 0.01). In conclusion, IL-1, IL-6, and IL-8 in the vaginal secretions are sensitive indicators of compound-induced mucosal toxicity. The described evaluation system is a valuable tool in identifying novel vaginal contraceptive microbicides, selecting out candidates that may enhance, rather than decrease, HIV transmission.

Prepubertal human chorionic gonadotropin injection affects postpubertal germ cell maturation and androgen production in rat testis

OBJECTIVES

To examine the effects of varying doses of prepubertal human chorionic gonadotropin (hCG) administration on postpubertal germ cell status and androgen status in rats. The long-term effects of prepubertal hCG administration on postpubertal testicular function are still debated.

METHODS

Forty male prepubertal Wistar rats, aged 20 days, were divided into four equal groups. Group 1 served as the controls. Each rat in groups 2, 3, and 4 received subcutaneous hCG injections of 5 IU, 10 IU, and 50 IU, respectively, on days 20 and 30 of life. Serum testosterone levels were estimated on days 33 and 70. On day 70, the left testis of each rat was harvested for DNA flow cytometric analysis.

RESULTS

The testosterone levels on day 33 progressively increased from groups 1 through 4, and the difference between any two groups was statistically significant. In contrast, the testosterone levels on day 70 were greatest in group 1 and progressively decreased in groups 2 through 4, with the lowest value in group 4. On day 70, only group 4 rats had a significantly reduced haploid cell population compared with all other groups.

CONCLUSIONS

Prepubertal hCG administration adversely affects testosterone levels, and a high dose of hCG has adverse effects on the germ cell haploid cell population. A critical reevaluation of the use of hCG is required in prepubertal boys, especially with respect to the dosage.

Involvement of tyrosine kinase and cAMP-dependent kinase cross-talk in the regulation of human sperm motility

Tyrosine phosphorylation and its upregulation by cAMP have been associated with capacitation and motility changes of spermatozoa. In the present study, washed spermatozoa were incubated for 6 h in protein-supplemented complete medium with or without kinase inhibitors to verify whether upstream activation of protein kinase A is indispensable for tyrosine phosphorylation and motility changes to occur in capacitating human spermatozoa. H89, a specific protein kinase A inhibitor, significantly inhibited the activity of sperm protein kinase A. However, this inhibition did not alter capacitation-related tyrosine kinase activation. Tyrosine phosphorylated proteins, motion parameters and the incidence of phosphotyrosine-immunoreactive spermatozoa were decreased only slightly. Conversely, genistein, a tyrosine kinase inhibitor which inhibited sperm tyrosine kinase but not protein kinase A, significantly reduced all the parameters studied. Spermatozoa incubated with cAMP and pentoxifylline showed a rapid enhancement of tyrosine phosphorylation and some of the sperm motion parameters, particularly hyperactivation. Inclusion of H89 reduced cAMP stimulation of tyrosine kinase, and tyrosine phosphorylation and motion parameters were reduced almost to basal values. Treatment with genistein reduced tyrosine kinase activity, especially in the soluble fraction of sperm extracts. A decrease in tyrosine phosphorylation of soluble proteins, 105, 81, 55 and 48 kDa, correlated with a significant reduction in sperm motion parameters. Hyperactivation was reduced by tenfold. Tyrosine phosphorylated proteins in the insoluble fraction and the incidence of tyrosine phosphorylated-positive spermatozoa were not reduced markedly. Upstream protein kinase A activation may be a facilitatory rather than an indispensable step in the capacitation-induced tyrosine phosphorylation mediating motility changes in human spermatozoa. Triton-x100 soluble tyrosine phosphorylated proteins, more than their insoluble counterparts, appear to be involved in the modulation of human sperm motion characteristics.

Effect of tyrosine kinase inhibitors on tyrosine phosphorylation and motility parameters in human sperm

Tyrosine phosphorylation has recently been associated with capacitation and suggested as a regulator of sperm movement, especially characterizing hyperactivation. The objective of this study was to verify if tyrosine phosphorylation of human sperm proteins was essentially required for the maintenance of motility as well as the development of hyperactivation. Washed sperm were incubated for 6 h in Ham's F10 + 0.35% HSA at 37 degrees C in 5% CO(2), with and without the tyrosine kinase inhibitors genistein, tyrphostin, erbstatin, or herbimycin A and the wide-spectrum kinase inhibitor staurosporin. The concentrations of the inhibitors used in the experiments did not induce sperm toxicity, as measured by membrane integrity and mitochondrial function assays. Samples incubated without the inhibitors (control), increased their tyrosine kinase activity (ELISA), the number and intensity of tyrosine-phosphorylated (PY) protein bands (Western blot), the incidence of PY-immunoreactive sperm (immunofluorescence), and some of the sperm motion characteristics (CASA), such as velocity (VEL), amplitude of lateral head displacement (ALH), and hyperactivation. Among the selective protein tyrosine kinase inhibitors, genistein was the most active and consistent, inhibiting sperm tyrosine kinase activity, PY proteins, incidence of PY sperm, and sperm motility and motion parameters, such as VEL, ALH, and hyperactivation. The rest of the kinase inhibitors decreased motion characteristics to a varied extent and had different effects on phosphorylation parameters. In general, they decreased PY phosphorylation of 2 proteins (83 and 54 kDa) present in whole sperm extracts, and two sets of proteins of low (39-49 kDa) and medium (55-87 kDa) molecular weight present in the Triton X-100-solubilized sperm protein fraction. This inhibition was evident regardless of the total tyrosine kinase activity of the samples or the incidence of PY-immunoreactive sperm. The described findings further support the association between motility and protein tyrosine phosphorylation in human sperm and point to certain proteins as the main linkers.

Epigastric heteropagus twins--a report of four cases

Asymmetrical conjoined twinning is an extremely rare congenital anomaly constituting only 1%-2% of all conjoined twins. In epigastric heteropagus twins (EHT), the dependent portion (parasite) is smaller than the host (autosite). The embryopathy is related to incomplete cleavage of the embryo at 2 weeks of gestation. However, some form of ischaemic insult in early gestation leads to selective atrophy of the cranial part of one of the monozygous twins. We report our experience with four cases of EHT and a review of the literature with a discussion of possible embryopathy.

AIIMS clinical score: a reliable aid to distinguish neonatal hepatitis from extra hepatic biliary atresia

It is important to distinguish neonatal hepatitis (NH) from extra hepatic biliary atresia (EHBA) in a neonate presented with jaundice as the former is purely medical management and the latter requires surgical procedure at the earliest. The observations on the critical evaluation of the neonatal jaundice cases led us to propose AIIMS clinical score (ACS) and this retrospective study was designed to evaluate the reliability of the ACS in all the 120 babies with jaundice referred to the pediatric surgery department during the past 10 year period. The ACS described here is based on 5 clinical parameters--Age, Jaundice, Colour of urine and stool and Clinical examination of liver. The accuracy of the hepatobiliary scan (HBS) with respect to the diagnosis of EHBA in this series, as compared to per operative cholangiography (POC) which is considered as the gold standard to distinguish these conditions was only 68%. However, ACS showed a sensitivity of 91.5%, a specificity of 76.3%, positive predictive value of 89.2%, negative predictive value of 80.5% and an overall diagnostic accuracy of 86.6%. ACS is reliable to distinguish NH from EHBA at bedside.

Incarcerated diaphragmatic hernia secondary to plication for eventration of diaphragm

Diaphragmatic plication is the procedure of choice for congenital diaphragmatic eventration. In the absence of complications, most newborns with eventration do well after plication and have normal long-term respiratory functions. However complications are rare. Recurrence, ipsilateral pneumothorax and rupture of the diaphragm have been reported in literature. We report a case of incarcerated diaphragmatic hernia in a two-year-old child who had undergone plication for eventration of the diaphragm at six months of age.

Percutaneous nephrostomy in children with ureteropelvic junction obstruction and poor renal function

OBJECTIVES

To evaluate the results of performing percutaneous nephrostomy (PCN) in all patients with kidneys with ureteropelvic junction obstruction (UPJO) and split renal function (SRF) of less than 10%, because the management of such cases is still under debate. If SRF improves, we perform pyeloplasty, otherwise nephrectomy is done.

METHODS

The records of all patients with UPJO (n = 20; 17 unilateral and 3 solitary kidney) with poor function who underwent PCN were analyzed. The PCN remained in situ for at least 4 weeks, during which patients received low-dose oral trimethoprim prophylaxis. Repeated renography was obtained after 4 weeks. If no improvement in the SRF had occurred, nephrectomy was performed, otherwise pyeloplasty was performed. The patients were followed up with renograms at 3 months, 1 year, 2 years, and 5 years.

RESULTS

Twelve of 17 kidneys with unilateral UPJO improved after PCN drainage and underwent pyeloplasty. The 5 kidneys that did not show improvement in the SRF underwent nephrectomy. In the patients with unilateral UPJO who improved after PCN drainage, the SRF increased to 29.2% +/- 12.6% and pyeloplasty was performed. At a mean follow-up of 2.3 years, none of these patients had developed hypertension, and the most recent SRF value was 31.4% +/- 12.8%.

CONCLUSIONS

Most of the poorly functioning UPJO kidneys show improvement in function and not all such kidneys should be removed without a trial of PCN.

Identification of thyroid regulatory elements in the Na-K-ATPase alpha3 gene promoter

A -1027 bp to + 108 bp region of Na-K-ATPase alpha3 gene promoter has been searched for the presence of thyroid response elements (TRE). Computer analysis of this sequence using a consensus TRE sequence revealed the presence of four putative TRE rich regions referred to as regions I (-636 to -457 bp), II (-218 to -106 bp), III (-106 to -6 bp) and IV (-6 to +108 bp). Cotransfection of the luciferase linked full length construct as well as constructs progressively devoid of the TRE rich regions in Cos1 cells revealed that regions I and III are positively regulated by T3 whereas there are some sequences in region II which can suppress the positive regulatory effect of region III but not of region I. TRE IV seems to have no functional role. EMSA of the three functional TRE rich regions (I, II and III) showed strong and specific interaction with thyroid hormone receptor (TR) cloned and expressed in baculovirus. The overall results suggest the regulation of Na-K-ATPase alpha3 gene by T3 is complex involving several thyroidal regulatory elements.

Factors affecting outcome in the management of posterior urethral valves

Children with posterior urethral valves (PUV) are at high risk for renal failure (RF). The outcome of renal function is significantly influenced by early diagnosis and the choice of primary therapy. We reviewed the outcome of renal function in 58 children with PUV. The choice of therapy in each case primary valve fulguration, vesicostomy, or high ureterostomy--was individually decided on the basis of the response to initial catheter drainage of the bladder. Patient age at diagnosis varied from newborn to 5.5 years, and follow-up ranged from 1.6 to 6 years (mean 3.9 years). The most common procedure was primary endoscopic valve ablation, which was carried out in 56.8% of cases. The other procedures were vesicostomy in 32.75% and high ureterostomy in 10.45%. Most neonates (66.6%) had RF at presentation, but one-half of them had achieved normal serum creatinine values at last follow-up. The recovery of renal function was lowest (33%) in older children where the diagnosis was delayed. A comparison between two groups of neonates and infants who differed on the basis of creatinine concentrations at 1 year of age suggested a statistically significant trend: children with normal or near-normal serum creatinine (0.8 mg/dl or less) by 12 months of age maintained good renal function at the time of final evaluation (1.0 mg/dl or less). Children with higher creatinine values at 1 year of age continued to have progressive RF. Seventy-five percent of the patients who had undergone early high ureterostomy after failure to respond to initial catheter drainage had regained normal renal function. We conclude that: serum creatinine at presentation is not predictive of subsequent renal function, but the values after a period of urinary-tract decompression are prognostically more useful; delay in diagnosis results in a poor outcome of renal function; and for optimal recovery of renal function, the choice of the primary procedure varies from case to case and can be determined by a systematic, stepwise approach (stepladder protocol).

High incidence of adriamycin cardiotoxicity in children even at low cumulative doses: role of radionuclide cardiac angiography

BACKGROUND/PURPOSE

Adriamycin (doxorubicin), a chemotherapeutic agent commonly used in the treatment of pediatric solid tumors, is known to have a dose-related cardiotoxicity, which is reported to be more common in children. The clinical manifestation of this is congestive cardiac failure (CHF), and this is fatal in 50% of the cases. Various strategies, including prospective multiple gated acquisition (MUGA) scan for early detection of the onset of cardiac damage has been recommended to decrease this fatality caused by cardiotoxicity.

METHODS

All children receiving Adriamycin for solid tumors, registered at our pediatric solid tumor clinic from January 1998 through June 1999, were included in the study. Cardiotoxicity was evaluated by using electrocardiogram (ECG)-gated radionuclide cardiac angiography (MUGA scan).

RESULTS

MUGA scans were performed on 55 patients in the above-mentioned period of 18 months. Twenty-three patients had only 1 baseline MUGA scan done, 12 of these are awaiting further studies at appropriate time and 11 are either dead or lost to follow-up. Of the remaining 32 patients, 13 have shown evidence of cardiotoxicity on MUGA scan done at a cumulative dose of 180 to 200 mg/m(2), in the form of decrease in left ventricular ejection fraction (LVEF) or abnormality in myocardial movements. Three of these 13 patients had clinical evidence of CHF. In 10 patients, timely discontinuation of Adriamycin, based on the MUGA report, probably has helped avoid the development of CHF.

CONCLUSION

Routine monitoring of all children receiving Adriamycin is required to avoid the mortality and morbidity of Adriamycin-related cardiotoxicity, which may develop at relatively low cumulative doses also.

Congenital diaphragmatic hernia

Over the last two decades there has been a constant improvement in the understanding of the pathophysiology of Congenital Diaphragmatic Hernia (CDH) and its management. However, the ideal treatment remains elusive. The earlier management strategy of immediate surgery is replaced by the principle of physiological stabilisation and delayed surgery. Conventional mechanical ventilatory techniques, with high pressures and hyperventilation to reverse ductal shunting and cause alkalinization, are being questioned because of the risks of barotrauma and consequent broncho-pulmonary dysplasia. It has also been shown that paralysis with pancuronium bromide for patients on conventional mechanical ventilation results in increased incidence of sensorineural hearing loss in childhood survivors of CDH. With the introduction of the concept of permissive hypercapnia and high frequency oscillation ventilation, the complications of pulmonary barotrauma are circumvented. Although ECMO therapy is invasive, yet has improved survival by about 15% independently, especially in critically ill infants who have the predictive mortality rate of more than 80%. Further insights into the pathophysiology of CDH and the introduction of less invasive therapeutic techniques in the form of high frequency oscillation ventilation, inhalation nitric oxide, surfactant, and perfluorocarbon liquid ventilation may even make the need for ECMO redundant.

Intestinal atresia

Intestinal atresia accounts for about one third of all cases of neonatal intestinal obstruction. The survival rate has improved to 90% in most of the series with the operative mortality being < 1%. The survival rate improves with distal atresias. An increased mortality is observed in multiple atresias (57%), apple peel atresia (71%), and when atresia is associated with meconium ileus (65%), meconium peritonitis (50%) and gastroschisis (66%). Although appearance of echogenic bowel on prenatal ultrasonography is suggestive of GI, it is confirmed in only 27% cases. Prenatal ultrasonography is more reliable in detection of duodenal atresia than more distal lesions. Short bowel syndrome is the major impediment in the management of jejunoileal atresia. Although total parenteral nutrition (TPN) is the main adjunctive treatment, it delays intestinal adaptation and may cause cholestasia and subsequent liver damage. Graduated enteric feedings, use of growth hormone, glutamine and modified diets containing low fat, complex carbohydrates and protein supplements have been used in a adults with short bowel syndrome to successfully diminish TPN requirements and enhance nutrient absorption in nearly half of the patients. Utilization of growth factors to facilitate intestinal adaptation and advances in small bowel transplant may improve the long-term outcomes in future.

Management of bladder exstrophy

The exstrophy-epispadias complex is a severe anomaly of the lower urinary tract. While the surgical reconstruction of normal anatomy in patients with this disorder was once considered impossible, modern management has made possible a near-normal reconstruction of the bladder and lower abdominal wall. Early operation in the neonatal period along with closure of the pelvic ring has been shown to significantly improve results in terms of continence and achievement of adequate bladder capacity. With the possibility of prenatal diagnosis, it is important that the counseling obstetricians and neonatologists should understand the basis of the surgical management and the outcome that can be expected.

Neonatal Hirschsprung's disease

Since the classic description of this disease by Harold Hirschsprung's. In 1886 just over a century ago, there has been a marked evolution in the diagnostic modalities, understanding of the pathophysiology, unraveling of genetic association and the treatment approach of this disease. Recent research on the molecular biology of the disease has bestowed us with a clearer understanding of the pathogenesis of the disease. Genetic deletions have been identified which explain the familial incidence of 3.6%-7.8%, and in some kindreds the inheritance rate approaches 50%. Improvement in the diagnostic approaches has evolved from full thickness rectal biopsy (under GA) to suction rectal biopsy. The development of the histochemical staining for acetylcholinesterase, allows rapid identification in the lamina propria of hypertrophied extrinsic nerve fibers which have proliferated in the absence of intrinsic ganglion cells. Frozen sections now permit screening for normal ganglia in the myenteric plexus from seromuscular biopsies during the definitive pull-through procedures or leveling colostomy. This service, however, requires significant infrastructure and an expert pathologist, not widely available. Hirschsprung's disease (HD) variants like intestinal neuronal dysplasia(IND), hypoganglionosis are better identified and treated with availability of histochemical staining. The three-stage procedure till date remains the gold standard; however, increasingly, the world over, two stage and even single stage procedures are being tried. In the era of minimally invasive surgery, perineal pull through procedure has been attempted with or without laparoscopic assistance.

Surgery in tuberculosis

Tuberculosis in children involves many organs and systems including lymphatics, lungs, CNS, GIT and genitourinary. Although the mainstay of treatment is medical, surgery has a definite role under specific circumstances. It is important to differentiate atypical mycobacterial infection wherein surgery is the primary modality of treatment. The lung is most commonly involved in tuberculosis and besides bronchoscopy, thoracic procedures range from tube thoracostomy to decortication and lung resection. Neurotuberculosis constitutes almost half the cases of extrapulmonary tuberculosis and tuberculous meningitis (TBM) is the commonest type of CNS involvement. Hydrocephalus is a late complication of TBM and shunt surgery is indicated when signs and symptoms of raised intracranial pressure persist despite adequate medical therapy. Abdominal tuberculosis could be peritoneal or gastrointestinal. Either form can complicate the other and each can present in acute, subacute or chronic form. Surgical therapy is reserved for complications like strictures, fistulae and GI bleed. Genitourinary tuberculosis constitutes 15-20% of all extrapulmonary disease and epididymitis is the most common manifestation in the males. Surgery is generally reserved for management of complications such as ureteral strictures, perinephric abscesses and nonfunctioning kidneys.

Gastric teratoma in children

Gastric teratoma (GT) comprises less than 1% of all teratomas in children. Though GT in the presence of immature neuroepithelial elements is regarded as malignant, the prognosis is excellent after complete excision of the tumor. Because of its rarity the world literature lacks a large study. Clinical experience with ten cases of GT is presented and discussed. Only one patient was female; the mean age at presentation was 3.2 months. Two cases were immature grade III GT; one of these had infiltrated the left lobe of the liver and the transverse colon while the other had metastasized to the regional lymph nodes and omentum. All the patients underwent complete excision. There were no deaths, and after a mean follow-up period of 4.2 years, all the patients had no recurrence and were healthy. Both the mature and immature types of GT have an excellent prognosis after complete excision of the tumor. Even when the immature type infiltrates surrounding structures, complete excision offers recurrence-free survival without requiring chemo- or radiotherapy.

High-throughput screening for lead optimization: a rational approach

Genetics, combinatorial chemistry and automation have greatly increased the number of therapeutic programs and compounds in the pharmaceutical industry pipeline. The increase in the number of new molecular entities (NMEs) has led to changes in the process by which compounds are evaluated during drug discovery and selected for clinical development. There is a need for the earlier determination of the absorption, distribution and elimination characteristics of NMEs, and drug metabolism scientists are working to develop higher-throughput in vitro screens for absorption, distribution and metabolism of compounds. These screens rely on advancements in analytical technology and molecular biology, and frequently use human or 'humanized' tissues. Throughput to determine in vivo pharmacokinetics has also progressed with the use of mixture dosing and sample pooling methods. The continued refinement of in vitro and in vivo ADME methods will allow the industry to evaluate the absorption and disposition characteristics of larger numbers of molecules and will ultimately allow the prediction of human pharmacokinetics at early stages of the development process.

Esophageal atresia and tracheo-esophageal fistula: a review

The improved survival of neonates with esophageal atresia and tracheo-esophageal fistula reflects the advancement in neonatal care and anaesthesia over the years. Chick embryo studies have given new insights in the embryopathy of esophageal atresia. It is now apparent that the various types of esophageal atresia could be explained due to selective discrepancy in the growth of the 3 folds in the region of tracheo-esophageal separation. The early disturbances in organogenesis which result in esophageal atresia also lead to other associated anomalies, the incidence of which varies from 40 to 55%. These anomalies have an important bearing on the survival outcome. The physiological aspects of esophageal atresia such as esophageal dysmotility and gastro-esophageal reflux are also vital in the long term and proper treatment of the associated defects. The criteria for an ideal esophageal substitute in long gap esophageal atresia have been determined and several options are now available with good results, such as: gastric transposition, colon, gastric tube and small intestine. IN developing countries, however, a high mortality is still attributed to late referrals, low birth weight, hypothermia and chest infection.

Gastroschisis and omphalocele

The survival rate of patients with abdominal wall defects has gradually improved with the advances in the investigation and treatment modalities. The present paper reviews the results of various treatment modalities and also analyses the long term results in these patients. A meta-analysis was performed via a medline search of English written clinical studies containing the text words "abdominal wall defects", gastroschisis and 'omphalocele or exomphalos" from 1953 to 1998. The present consensus on operative management of abdominal wall defect is to provide primary closure, if it can be achieved without haemodynamic or respiratory compromise. Patients with primary closure on analysis were found to have better survival rates, reduced risk of sepsis and overall, a shorter hospital stay. However, resumptions of oral feeds, duration of total parenteral nutrition (usually lasting 10-15 days) and ventilatory support required postoperatively did not significantly differ in the primary and silo technique. Long term outcome of these patients is generally good, but they have high incidence of GER (40-50%) for which they should be on regular follow up.

Transcriptional and post-transcriptional regulation of Na+,K(+)-ATPase alpha isoforms by thyroid hormone in the developing rat brain

Transcriptional and post-transcriptional events involved in the induction of sodium potassium adenosine triphosphatase (Na+,K(+)-ATPase) by thyroid hormone (T3) were investigated. In vitro transcription of nuclei isolated from cerebra of 5- and 15-day-old normal and hypothyroid rats showed that transcription of all alpha mRNA isoforms (alpha 1, alpha 2 and alpha 3) of Na+,K(+)-ATPase are sensitive to T3. This is evidenced by a 50-70% reduction in the rates of transcription of alpha 1 and alpha 3 mRNA and 20-40% reduction of alpha 2 mRNA in nuclei from hypothyroid cerebra compared with those from normal controls. Preincubation of nuclei from hypothyroid cerebra with T3 prior to transcription also showed an increase in the rates of transcription of these mRNAs. At the post-transcriptional level, T3 enhanced the half life of alpha 3 mRNA by 1.5-fold with no discernible effect on alpha 1 and alpha 2 mRNA.

A common genetic basis for idiosyncratic toxicity of warfarin and phenytoin

CYP2C9 is mainly responsible for the metabolic clearance of phenytoin and (S)-warfarin. We have shown previously that mutations in the CYP2C9 gene are associated with diminished metabolism of (S)-warfarin, and so we have now studied the metabolism of phenytoin to its primary inactive metabolite, (S)-pHPPH, by these mutant enzymes. Kinetic parameters were determined for (S)-pHPPH formation using recombinant CYP2C9 variants purified from insect cells. The data demonstrate that the CYP2C9*3 gene product retains only 4-6% of the metabolic efficiency of the wild-type protein, CYP2C9*1, towards phenytoin and (S)-warfarin. Consequently, we suggest that homozygous expression of CYP2C9*3 may represent a common genetic basis for (apparently) idiosyncratic toxicities that have been reported for these two low therapeutic index drugs.

Effect of stiripentol dose on phenytoin-induced teratogenesis in a mouse model

PURPOSE

Previous studies have suggested that polytherapy by design may aid in the management of human pregnancies complicated by epilepsy. However, mechanistic parallels must be drawn between the models of teratogenesis and human pregnancies, and doses of the second agent given to minimize side-effects must be justified. This study sought to determine the lowest dosage of stiripentol (STP) protective against phenytoin-induced teratogenesis in a mouse model, and to determine mechanistically if inhibition of oxidative metabolism by STP in vitro decreased production of reactive phenytoin (PHT) metabolites.

METHODS

Pregnant SWV mice were assigned to control or treatment groups of STP alone, PHT alone, or PHT with ascending doses of STP coadministration. Treatments continued from Day 6 to Day 18 of gestation when fetuses were examined for developmental anomalies. [14C]PHT was incubated in mouse liver microsomes with and without NADPH and in the presence or absence of STP or piperonyl butoxide. Covalent binding of [14C] was measured.

RESULTS

There were no dose-related differences in the frequency of fetal malformations per litter among groups treated with STP alone. However, STP (all doses) reduced the frequency of PHT-induced malformations. Covalent binding of [14C]PHT was NADPH-dependent and was inhibited by either piperonyl butoxide or STP.

CONCLUSIONS

The beneficial effects of STP occurred at concentrations below the therapeutic range for its anticonvulsant effects. These results support the concept of polytherapy by design to reduce the risk of teratogenesis associated with PHT.

Surgical aspects of chronic constipation in children

Chronic constipation accounts for 3% of paediatric visits. These patients can be broadly classified into three groups: (a) medical group (60-70%), (b) surgical group (20-25%), (c) refractory constipation group (5-10%). The first two groups can be managed by dietary adjustments and surgery respectively. The recognition and management of refractory constipation is a slower process and needs close scrutiny and perseverance before a definite therapeutic option could be decided.

Somatic growth and renal function after unilateral nephrectomy for Wilms' tumor

Solitary kidneys in renal donors and patients who have undergone unilateral nephrectomy for malignant disease have been reported to undergo hyperfiltration injury. This study was undertaken to evaluate the somatic growth and development of followed-up patient after Wilms' tumor to evaluate their renal function and identify any evidence of injury in the remaining kidney. The growth and development of all the children was found to be normal, as was DTPA clearance. Microalbuminuria in 24-h urinary collections was detected in 84% of the patients, indicating evidence of hyperfiltration injury. This study highlights the need for close monitoring of the renal function of long-term follow-up patients after Wilms' tumor in addition to the routine monitoring for tumor recurrence.

Lipid metabolising enzymes in isolated rat testicular germ cells and changes associated with meiosis

To assess the lipid metabolising potential of testicular germ cells undergoing meiosis, spermatocytes and spermatids were isolated from adult rat testis and purified by centrifugal elutriation followed by density gradient centrifugation. Seven key enzymes of lipid metabolism (namely beta-hydroxybutyrate dehydrogenase, carnitine acetyl transferase, ATP citrate lyase, hydroxyacyl-CoA dehydrogenase, glycerol 3-phosphate dehydrogenase, acetyl-CoA carboxylase and long chain acyl-CoA synthetase) were assayed in cell homogenates. The results indicated that germ cells possess the key enzymes for de novo synthesis and oxidation of fatty acids. The significant increase in activities of anabolic enzymes and decrease in activities of catabolic enzymes in post-meiotic germ cells indicated a shift in lipid metabolism towards fatty acid synthesis during meiosis. Long chain acyl-CoA synthetase activity was not detected in the two cell types. The study indicates a major reorganization of fatty acid turnover during meiosis with equilibrium shifting in favour of synthesis.

Changes in carbohydrate metabolism of testicular germ cells during meiosis in the rat

A study was undertaken to estimate the activities of the key enzymes of glycolysis, the pentose phosphate pathway and the tricarboxylic acid (TCA) cycle in purified rat spermatocytes and spermatids, which have been shown to die in glucose-containing medium and require lactate/pyruvate for maintaining normal ATP concentrations. The aim was to elucidate the changes in the glycolytic and oxidative potential of germ cells undergoing meiosis. Pachytene spermatocytes and round spermatids from adult rat testis were purified to approximately 90% purity by trypsin digestion followed by a combination of centrifugal elutriation and Percoll density gradient centrifugation. After the purity and viability of these cells had been established, their contents of hexokinase, phosphofructokinase, lactate dehydrogenase (LDH) and LDH-X of glycolysis, glucose 6-phosphate dehydrogenase of the pentose phosphate pathway and citrate synthase, aconitase, malate dehydrogenase and 2-oxoglutarate dehydrogenase of the TCA cycle were estimated. These enzymes were also estimated in epididymal spermatozoa for comparison with the testicular germ cells. The results indicate greater activity of glycolytic and pentose phosphate pathway enzymes in spermatocytes than in spermatids, which exhibited greater activity of TCA cycle enzymes than the former. The difference in activity was statistically significant for most of the enzymes studied. In contrast, spermatozoa exhibited markedly greater activity of glycolytic enzymes and significantly lower activity of pentose phosphate pathway and TCA cycle enzymes than did the testicular germ cells. We conclude that the unusual dependence of spermatids exclusively on lactate may be due to their lower glycolytic potential, whereas spermatocytes with comparatively greater glycolytic activity have an intermediate dependence on lactate and are therefore able to utilise lactate, pyruvate, or both, while retaining a better ability to utilise glucose. Spermatozoa with the greatest glycolytic potential and the lowest TCA cycle activity appear to be 'programmed' to utilise exclusively glucose/fructose for energy.

Bilateral Wilms tumor: an eleven year experience

Over the last 11 years, 101 patients of Wilms tumor were treated at our hospital. Of these, 7 had bilateral Wilms tumors (BWT). The first two patients were referred in terminal stages and died. Of the latter five, three have survived while one is on treatment. One patient succumbed to liver metastasis, he had stage III disease on one side and was irregular in his chemotherapy protocol. Remarkably, one of the survivors was cured even after developing vertebral metastasis, retroperitoneal recurrence and bilateral lung metastasis. Part of the success was due to "salvage chemotherapy regimens" using Cis-plantinum, ifosphamide and VP-16. Flow cytometric analysis of DNA ploidy performed on only three of the five patients showed that two tumors were aneuploid and one was diploid. Spectacular cure rates can be achieved in BWT by renal conservation surgeries and effective chemotherapy. The use of "salvage chemotherapeutic regimes" and the study of DNA ploidy is being highlighted.

Management of hydrocephalus

The present study is an analysis of 747 patients with hydrocephalus, treated and followed up in the Hydrocephalus Clinic run by the department of Paediatric Surgery at the All India Institute of Medical Sciences, New Delhi. The distribution of patients was: congenital-46%, post-meningomyelocoele excision-28%, post-meningitic-21% and others-5% (including post haemorrhagic and post encephalocoele excision hydrocephalus. The average age was 7 months in the shunted group and 10 months in the medical group with overall male to female ratio of 2.3:1. The data were analysed to study the effect of treatment on ventriculomegaly and mental development with special reference to the type of treatment (shunt versus medical) and age at starting treatment. The probability of shunt failure was also studied. A comparison of ventricular size in US/CAT scans between the time of starting treatment and last follow-up revealed improvement in ventriculomegaly in 60% of the shunted patients but only 30% of the medically treated patients. A significant difference was particularly noted in patients with severe hydrocephalus, 72% and 22%, respectively. Comparison of the mean Mental Performance Quotient (MPQ) scores in the shunted & medically treated patients also revealed significantly better MPQ scores in the shunted group (p = < 0.001). Probability of shunt survival, as depicted by the Kaplan-Meier survival curve, revealed that there is a high rate of shunt failure in the first 12 months, followed by a dramatic slowing down. Our observations support the contention that CSF shunt surgery offers better outcome than medical management even when ventriculomegaly is severe at the time of presentation.

Occult spinal dysraphism

When spina bifida is associated with skin abnormalities such as dimples, sinus tracts hypertrichosis, or capillary hemangiomas, there is a high incidence of an occult intraspinal lesion such as epidermoid and dermoid tumours, lipomas, diastematomyelia, dural bands and tethered spinal cord. The present study consists of 50 patients with occult spinal dysraphism treated with the diagnosis of lipomeningomyelocoele (20), lumbosacral lipoma (15) and diastematomyelia (15). The clinical presentation varied from lipoma in the lumbosacral region, dermal sinus, cutaneous hemangioma and hypertrichosis. The age range varied from 2 months to 7 years with an average of 2 years. 40% patients had neurological deficit at the time of presentation which varied from lower limb weakness to bladder & bowel involvement. All patients underwent laminectomy of the lumbar and lumbo-sacral spine with excision of intraspinal lipoma, excision of bony or cartilaginous spur in diastematomyelia and detethering of the conus medullaris & cauda equina. No patient developed late neurological deficit.

Neurogenic bladder: urodynamic and surgical aspects

Children with spina bifida often have vesico-urethral dysfunction manifesting either as upper urinary tract deterioration or voiding dysfunction, chiefly incontinence. Surgery of the back and presence of or increase in hydrocephalus may contribute to neuro-urologic worsening; secondary cord tethering and syrinx or hydromyelia may be additional factors coming into play later in life. Urodynamic assessment using simple modalities like uroflowmetry, external sphincter EMG, residual urine volume and cystometry provide data useful to classify patients according to detrusor and sphincter activity. Besides diagnosis, urodynamic studies are useful in guiding therapy of children with vesico-urethral dysfunction, and for their follow-up to detect sub-clinical deterioration. They also help to prognosticate risk of upper tract deterioration and the possible success of measures to contain incontinence. Urodynamic data in thirty one patients with spinal dysraphism who presented to us with urologic symptoms were analysed. Twenty-three children had hyper-reflexic bladders while in the other 8 the bladder was areflexic. 13 children showed upper tract dilatation. The leak point volume was significantly lower in this group of patients compared to those who did not show upper tract dilatation. Our results are comparable to earlier similar studies.

Gastric transposition for esophageal replacement in children--an Indian experience

Most pediatric surgeons are wary of gastric transposition as a means for esophageal replacement in children, especially during infancy. We present our initial experience of this technique in five children followed up for an average 1.7 years postoperatively. Four of them were infants (age range 5 m to 10 m at the time of transposition) with wide-gap esophageal atresia, while one was operated upon for an extensive corrosive esophageal stricture at 4 years age. The stomach was placed transhiatally in 3 patients and through the retrosternal route in 2 patients. A gastric outlet drainage procedure was performed in all cases. The average age at transposition in the 4 infants with esophageal atresia was 8.5 months and the mean weight was 7.4 kg. Three of the four infants required postoperative ventilation (mean duration 40 hours) and the average duration of hospital stay was 24 days. Our first transposition in a chubby infant resulted in death (20% mortality for this series) due to difficult ventilation. Other complications included anastomotic leak and subsequent stricture (one patient), adhesive obstruction (one patient), transient Horner's syndrome and recurrent laryngeal nerve palsy (one patient), and poor weight gain (one patient). Postoperatively, while the pattern of liquid gastric emptying was variable, no duodenogastric reflux was demonstrable. Thus gastric transposition is a safe, relatively simple and physiologic procedure in infancy and childhood and has given good functional results.

Seasonal variations in Sertoli and germ cell marker enzymes in testis of rhesus and bonnet monkeys

Variations in specific activities of the marker enzymes of Sertoli and germ cells during breeding (November-December) and non-breeding (May-June) seasons were investigated in rhesus and bonnet monkeys maintained under laboratory conditions. The marker enzymes selected for testicular cells were-Sertoli cells: beta-glucuronidase, gamma-glutamyl transpeptidase; pre-meiotic germ cells: glucose 6-phosphate dehydrogenase, malate dehydrogenase, alpha-glycerophosphate dehydrogenase; mature germ cells: LDH-X, sorbitol dehydrogenase. Results have indicated significant seasonal variation in marker enzymes only in rhesus testis. Marker enzymes of Sertoli cell increased while those of germ cell decreased significantly during non-breeding season. Marker enzymes of mature germ cells were affected much more drastically than those of the pre-meiotic germ cells.

Differential effects of hypothyroidism on Na-K-ATPase mRNA alpha isoforms in the developing rat brain

In the developing rat cerebrum, the level of different isoforms of Na-K-ATPase mRNA increases significantly during the first three postnatal weeks, which represent the critical period of synaptogenesis and myelination-the two thyroid hormone-sensitive maturational events. To determine the possible functional relationship of these isoforms with maturational events in the developing brain and their mode of regulation by T3, we have examined the effect of hypothyroidism on the expression of the different alpha-isoforms (alpha 1, alpha 2, and alpha 3) of Na-K-ATPase mRNA covering the first 3 wk of postnatal development. Quantitation of these mRNAs from cerebra of 1-, 5-, 10-, 15-, and 20-d-old normal and hypothyroid rats by Northern blot analysis indicate that alpha 3 mRNA is not only predominantly expressed throughout this entire period of study but also represents the species which is most severely affected in the hypothyroid brain. The relative sensitivity for the expression of these mRNAs to T3 were alpha 3 > alpha 1 > alpha 2. These results, together with the report of predominant expression of the alpha 3 isoform in neuronal cells, suggest specific functional involvement of this isoform with the decisive maturational events in the rat brain. Kinetic studies on in vivo induction of Na-K-ATPase alpha-mRNAs by T3 in the 15-d-old hypothyroid rat shows clear stimulation of all the isoforms within 1 h of the administration of the optimal dose (200 micrograms T3/100 g body wt) suggesting a direct, possibly transcriptional effect of the hormone on the expression of these genes.