Spectral technique with convergence analysis for solving one and two-dimensional mixed Volterra-Fredholm integral equation

A numerical approach based on shifted Jacobi-Gauss collocation method for solving mixed Volterra-Fredholm integral equations is introduced. The novel technique with shifted Jacobi-Gauss nodes is applied to reduce the mixed Volterra-Fredholm integral equations to a system of algebraic equations that has an easy solved. The present algorithm is extended to solve the one and two-dimensional mixed Volterra-Fredholm integral equations. Convergence analysis for the present method is discussed and confirmed the exponential convergence of the spectral algorithm. Various numerical examples are approached to demonstrate the powerful and accuracy of the technique.

Functional outcome of Hirschsprung's disease in children: A single center study at The Children's Hospital Lahore

AIM

Hirschsprung's disease (HD) is a congenital bowel disorder resulting in functional dysmotility. Advancement in surgical techniques has improved outcomes, but recent studies have identified problems having significant impact on patient's quality of life. The aim of this study is to analyze postoperative functional outcome after definitive surgery for Hirschsprung's disease.

METHOD

A retrospective study was conducted at the Department of Pediatric Surgery, The Children's Hospital Lahore. The record of 64 patients was reviewed from the year 2009 to 2019. Parents were interviewed on phone calls and a predesigned questionnaire was filled. Degree of constipation, incontinence and voluntary bowel movements was analyzed according to Krickenbeck classification.

RESULTS

Median age at initial presentation was 11 days, with male to female ratio of 3.9:1. Most common presentation was delayed passage of meconium (38%). Diagnosis was made on biopsy in 70.3%, but contrast enema and biopsy in 29.7%. Aganglionosis was limited to short segment in 81.3% and long segment in 14.5%. Decompressing enterostomy was made in 63% at a mean age of 191 days. Definitive surgery included Duhamel pull-through in 89.1%. Mean age at follow-up was 10.6 ± 4.19 years and alive patients were 95.4%. Postoperative enterocolitis was reported by 27%, while 35.5% reported fecal incontinence and 16.1% complained of constipation. 80% could voluntarily hold bowel movement, among which 5% had a feeling of urge and 15% had the capacity to verbalize. In 25% of the patients, fecal incontinence was a constant social problem and in 25% of these patients constipation was resistant to diet and laxatives.

CONCLUSION

On long-term follow-up, fecal incontinence was more worrisome, affecting quality of life and requiring help of the bowel management program. Such patients need close follow-up after definitive procedure, so that they have normal stooling habits in their adulthood and lead a normal life.

Evisceration of appendix via drain site - a rare complication in a child

INTRODUCTION AND IMPORTANCE

Abdominal drains prevent fluid accumulation and help drain fluid (blood, pus). In recent years, abdominal drains have been used less frequently due to drain-associated complications, like infections, anastomotic leakage, and the potential for the evisceration of intra-abdominal organs on drain removal.

CASE PRESENTATION

We present a young female with evisceration of the appendix via the drain site, successfully managed by abdominal exploration and appendectomy.

CASE DISCUSSION

The use of prophylactic abdominal drain is controversial and is of limited use even in complicated appendicitis in the modern era of antibiotics. If a drain is inserted, it should be removed at the earliest to avoid associated complications.

CONCLUSION

Abdominal drain usage should be minimized in children to avoid post-operative complications.

Outcome Of Laparoscopic Percutaneous Extra Peritoneal Closure Versus Open Repair For Paediatric Inguinal Hernia

BACKGROUND

Laparoscopic inguinal hernia repair (LIHR) has many benefits like less frequency of metachronous contralateral hernias, minimum complications, comparatively less duration of operation and better cosmetic outcome as compared to the open technique. Objective of the study was to compare the outcome of laparoscopic percutaneous extra-peritoneal closure (LPEC) and open repair for paediatric inguinal hernia in terms of contralateral metachronous hernia, operative time and recurrence.

METHODS

A randomized controlled trial was conducted at the Department of Paediatric Surgery, Children Hospital Lahore. Non-probability purposive sampling was used, and 296 cases were divided into group-1(managed with conventional open repair) and group-2 (managed with laparoscopic Percutaneous Extra-peritoneal closure). After taking informed consent, data was collected, and cases were studied for operative time, contralateral metachronous hernia and recurrence till 6 months postoperatively. Data analysis was done through SPSS 22.0. Chi-square and independent sample t-test was used for comparison. p-value ≤0.05 was taken as significant.

RESULTS

The mean operative time was statistically less in the LPEC group (24.79±3.44 minutes) when compared to the open repair group (28.71±4.54 minutes), p-value <0.001. In the Open repair group, there were 19 (12.8%) cases that had contralateral metachronous hernia, while in the LEPC group, 2 (1.4%) cases had contralateral metachronous hernia p-value <0.001. In the Open repair group, 4(2.7%) cases had a recurrence, while in LPEC group 1 (0.7%) cases had a recurrence, with statistically same recurrence rate, p-value >0.05.

CONCLUSIONS

The LPEC technique is better than conventional open repair in terms of CMIH, operative time, and recurrence rate.

Burnout Among Postgraduate Residents Using Copenhagen Burnout Inventory

BACKGROUND

Generally, the healthcare workers have a stressful job and it includes both physical and mental stress. We conducted this study to determine the burnout among postgraduate residents (PGR's). .

METHODS

This cross-sectional study was conducted at The Children's Hospital and The Institute of Child's Health, Lahore over a period of 3 months. A total of 113 PGR's participated in this study. Burnout was measured using Copenhagen Burnout Inventory (CBI). Questionnaire was filled by participants on paper. Results were analyzed through SPSS-26.

RESULTS

In this study, most of the participants (n=70) were females. Mean age of the participants was 28.6±2.035 years. More than 50% participants suffer from moderate to severe burnout. Nine percent of participants had high personal and client related burnout. The highest mean score was for personal burnout scale. When burnout scores were categorized according to demographic details, personal burnout was significantly higher among those who considered that they are burnout (p=0.000) and work burnout was significantly higher among those who travelled to the workplace by their cars (p=0.025). Burnout was higher among females, those who have long duration to travel from their homes to the hospital and whose parents were doctors; however, the difference was not significant. The scale showed a good overall internal reliability (Cronbach's alpha=0.697).

CONCLUSIONS

This study showed a high rate of burnout among PGR's that needs to be addressed and adequate measures should be taken to reduce it.

Jejunoileal atresia: a case-series of 63 neonates and risk factors to mortality

Introduction

Jejunoileal atresia (JIA) among neonates is still a condition which has huge morbidity and mortality, particularly in the developing world. We share a case series of JIA in context of their presentation, management, and outcome.

Materials and methods

This study was conducted at Children’s Hospital and Institute of Child Health, Lahore, over 1 year. We included all patients presenting with JIA, and their demographic details, presentation, investigations, treatment strategies, and the outcome were noted at a pre-designed proforma. All data were analyzed using SPSS version 26.

Results

A total of 63 neonates with JIA were included. Most of them (79.4%) presented after 48 h of life, and the mean age at presentation was 5.68 ± 4.75 days. There were 37 male patients (58.7%), and 51 (81%) were full-term. The most common presenting complaint was not being able to pass meconium (88.9%). Type III atresia was the most common subtype (41.3%). Most of them underwent resection without tapering. The mean hospital stay was 12.81 ± 6.53, and it was significantly longer among those who underwent re-exploration (P = 0.034). Twenty-three patients (36.5%) expired within 6 months of follow-up. The only significant factor for mortality was the presence of short bowel syndrome (P = 0.030). All other demographic and management factors did not alter the mortality rate.

Conclusion

Management of surgical neonates is a difficult job in developing countries with limited resources. There is a high mortality rate of neonates following JIA surgeries, and surgeons in these countries must fight on many fronts to improve the outcome.

Impact of Removing Race Adjustment When Estimating GFR on Chronic Kidney Disease Staging

Introduction/Objective

Determination of glomerular filtration rate (GFR) is essential in assessment of kidney function, particularly in patients with chronic kidney disease (CKD). Formulas were developed to calculate estimated GFR (eGFR), as direct measurement is cumbersome and not amenable to routine monitoring. CKD-EPI is the most widely used formula for eGFR, using parameters of serum creatinine, gender, race, and age. A race adjustment was added from an unfounded assumption that Black patients have more muscle mass, increasing their eGFR by about 16%. There is concern on the impact of “correcting” for Black race on patient management, utility of eGFR, and its possible contribution to healthcare disparities. This study examined the impact of eliminating race adjustment from the CKD- EPI formula on CKD staging in patients at a large safety-net hospital in an academic medical center.

Methods/Case Report

80090 serum creatinine values from 56676 adult patients (31.4% Black, 67.5% female, median age 51 yrs) were collected from the electronic medical record (Epic, Verona, WI) over a 16-month timeframe. Values were excluded if they lacked age, gender, self-identified race, or serum creatinine. eGFR was calculated using the CKD-EPI equation with and without race modifier, and CKD staging was performed using 2012 Kidney Disease: Improving Global Outcomes guidelines.

Results (if a Case Study enter NA)

In our cohort, only 50.8% of Black patients are in CKD1, indicative of no CKD, compared to 67.9% of non-Black patients. Given that these two cohorts are demographically similar, this shows a discrepancy in kidney function even before removing the race adjustment. After removal of the race modifier, 28.1% of Black patients were reclassified into a more severe CKD stage. The most restaging occurred from CKD3A to 3B (39%).

Conclusion

Many Black patients in our study were reclassified to a more severe CKD stage, with the highest percentage of patients restaged to CKD3B, which would have attracted clinical attention for nephrology referral. We recommend removal of the race adjustment in eGFR, given its basis in the incorrect belief in biological differences between races. It perpetuates systemic racism and discrimination in healthcare, and its removal will provide more equitable care and reduce healthcare disparities. Future studies should examine the increase in resources required to provide adequate medical care to patients who will be placed into a more severe CKD stage.

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

BACKGROUND

Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality.

METHODS

We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis.

FINDINGS

We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36-39) and median bodyweight at presentation was 2·8 kg (2·3-3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88-4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59-2·79], p<0·0001), sepsis at presentation (1·20 [1·04-1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4-5 vs ASA 1-2, 1·82 [1·40-2·35], p<0·0001; ASA 3 vs ASA 1-2, 1·58, [1·30-1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02-1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41-2·71], p=0·0001; parenteral nutrition 1·35, [1·05-1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47-0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50-0·86], p=0·0024) or percutaneous central line (0·69 [0·48-1·00], p=0·049) were associated with lower mortality.

INTERPRETATION

Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030.

FUNDING

Wellcome Trust.

Spontaneous gastric perforation: is it really common?

Background

Neonatal gastric perforation (NGP) is a rare, serious, and life-threatening condition which needs early recognition with prompt intervention for better prognosis. Its etiology is not yet well established, but multiple speculations have been put forth for its etiopathogenesis. Few most considered are traumatic, spontaneous, or secondary to inflammatory process like necrotizing enterocolitis. This study describes the etiological and prognostic factors for patients with NGP in our experience at a single center.

Results

A total of 46 neonates were included. Male gender predominated with M:F being 1.7:1. Most (n=36) neonates presented within 10 days of life whereas 8 neonates presented within 15 days. At presentation, gas under diaphragm was the most common radiologic finding in 25 (54.3%) neonates. On exploratory laparotomy, it was found that greater curvature was involved in maximum number of cases (n=27), followed by lesser curvature and anterior and posterior walls of the stomach. Most of perforations were within 1–5 cm in size. Gastrorrhaphy was done in all cases, and in two cases, feeding jejunostomy was done along with repair for feeding purpose. Finally, spontaneous NGP was diagnosed in 30 (60.8%), and NEC patches on other parts of the intestine were seen in 11 patients. Postoperatively, 28 neonates developed complications in the form of sepsis (n=13), wound infection (n=10), and burst abdomen (n=5). Regarding clinical outcome, 27 (58.7%) were discharged from the hospital whereas 19 (39.3%) patients died.

Conclusion

Our results show that spontaneous NGP is most commonly associated with NEC in our population, usually affecting the greater curvature. We observed a high mortality rate; however, good ICU care may improve the survival.

Outcome of urethral mobilization and advancement after anterior hypospadias surgery

Background

In hypospadias surgery, despite continued refinement of various surgical procedures, there is no completely satisfactory technique in terms of complications and cosmesis. In recent literature, urethral mobilization and advancement (UMA) is gaining popularity in the management of distal penile hypospadias with no or very low complication rate as compared to all other techniques. The aim of this study is to share our results by using UMA in the management of anterior hypospadias with or without chordae.

Results

A total of 60 patients of anterior hypospadias having the mean age 57.15 ± 38.73 months were included. The mean length of hospital stay was 2.83 ± 1.33 days. The only peroperative complication was urethral injury during urethral mobilization seen in one patient. The most common postoperative complication was hematoma seen in five (8.3%) cases. Two patients (3.3%) had retraction of urethra. One patient had wound infection. Stenosis was labeled in four (6.6%). At 3 months follow-up, 93.3% patients had slit-like meatus and good urinary stream.

Conclusion

We found that UMA technique had good functional as well as excellent cosmetic outcome, so the technique can be adopted for anterior hypospadias correction.

Synergistic potential of propolis and vitamin e against sub-acute toxicity of AlCl(3) in albino mice: in vivo study

Current study evaluated the synergistic potential of propolis and vitamin E against sub-acute toxicity of aluminum chloride on different biochemical parameters and liver histology. Swiss albino mice (n=42) were randomly divided into seven groups. Group I received 0.2 ml of 0.9 % saline solution, Group II received Propolis (50 mg/kg b.w.), Group III received vitamin E (150 mg/kg b.w.), Group IV received AlCl(3) 50 mg/kg b.w., Group V received AlCl(3) + Propolis, Group VI received AlCl(3) + vitamin E and Group VII received AlCl(3) + propolis + vitamin E. Blood and tissue samples were collected after 7 and 21 days. The body weight of the animals significantly increased in all groups except Group IV. The concentration of serum high density lipoprotein significantly decreased in Group IV and increased in Group V, VI and VII. The level of aspartate aminotransferase, alanine transferase, alkaline phosphatase, triglycerides, total cholesterol, and low density lipoprotein significantly increased in AlCl(3) treated group and increased in Group V, VI and VII. Tissue sections were processed and stained by hematoxylin and eosin. Group II showed cellular necrosis. Group V, VI showed decreased number of vacuolization, sinusoidal spacing and macrophage cell infiltration. Group VI showed less degenerative changes in the third week. Vitamin E and propolis in combination with Al provides more protection against AlCl(3) induced toxicity.

Duplication Cyst with Intestinal Volvulus Causing Intestinal Atresia/Stenosis in Neonates

Duplication cysts of small bowel seldom present in newborns and usually represent the development of complications. In utero complications may lead to mesenteric vascular accidents and thus resulting in intestinal atresias. We report three neonates with duplication cyst of small bowel causing localized intestinal volvulus, leading to small bowel intestinal atresia/stenosis. The neonates underwent excision of the duplication cyst and resection anastomosis of the small bowel. Post-operative recovery was uneventful in all three of them.

MHD convective heat transfer in a discretely heated square cavity with conductive inner block using two-phase nanofluid model

The problem of steady, laminar natural convection in a discretely heated and cooled square cavity filled by an alumina/water nanofluid with a centered heat-conducting solid block under the effects of inclined uniform magnetic field, Brownian diffusion and thermophoresis is studied numerically by using the finite difference method. Isothermal heaters and coolers are placed along the vertical walls and the bottom horizontal wall, while the upper horizontal wall is kept adiabatic. Water-based nanofluids with alumina nanoparticles are chosen for investigation. The governing parameters of this study are the Rayleigh number (10³ ≤ Ra ≤ 10⁶), the Hartmann number (0 ≤ Ha ≤ 50), thermal conductivity ratio (0.28 ≤ k_w ≤ 16), centered solid block size (0.1 ≤ D ≤ 0.7) and the nanoparticles volume fraction (0 ≤ ϕ ≤ 0.04). The developed computational code is validated comprehensively using the grid independency test and numerical and experimental data of other authors. The obtained results reveal that the effects of the thermal conductivity ratio, centered solid block size and the nanoparticles volume fraction are non-linear for the heat transfer rate. Therefore, it is possible to find optimal parameters for the heat transfer enhancement in dependence on the considered system. Moreover, high values of the Rayleigh number and nanoparticles volume fraction characterize homogeneous distributions of nanoparticles inside the cavity. High concentration of nanoparticles can be found near the centered solid block where thermal plumes from the local heaters interact.

A Rare Fetal Firearm Injury

Firearm injury (FAI) in pregnant women is reported in the literature; however, no reference to date was found to address the neonatal abdominal surgery performed after maternal FAI. FAI during fetal life is extremely rare and very few cases have been reported. We present a report of a 37-week gestation newborn whose mother had an accidental FAI. The neonate was delivered by emergency caesarian section along with emergency laparotomy of the newborn. The baby presented at eight hours of life, who was managed surgically in emergency for multiple small and large bowel perforations and a piece of bullet was recovered from anterior part of thigh.

Ingested Metallic Spool: A Rare Cause of Acquired Tracheoesophageal Fistula

Foreign body (FB) ingestion is a common problem in children. Prolonged impaction of FB in esophagus may result in tracheoesophageal fistula (TEF). A 6-year-old girl presented with progressive dysphagia and recurrent chest infections. No history of FB ingestion was given by parents. Further investigations revealed FB (spool) in cervical esophagus. Patient was successfully managed by surgery through trans-cervical approach.

Varied Presentation of Congenital Segmental Dilatation of the Intestine in Neonates: Report of Three Cases

Congenital segmental dilatation (CSD) of the intestine is a rare developmental anomaly characterized by sharply demarcated dilatation of a gastrointestinal segment and may present with intestinal obstruction. We report three cases of CSD of the intestine in neonates with varied presentation. First patient was mistaken as pneumoperitoneum on abdominal radiograph, which led to initial abdominal drain placement. The 2nd patient was a case of anorectal malformation associated with congenital pouch colon (CPC) and CSD of ileum; and the third case presented as neonatal intestinal obstruction and found to have CSD of ileum. All the patients were successfully managed in our department.

Hernia of umbilical cord: report of three unusual cases

Congenital hernia of umbilical cord is a less frequent entity in newborns and occasionally associated with other maladies. Herein, we report three unusual cases of hernia of umbilical cord. First case was associated with in-utero evisceration of entire small bowel through the presumably ruptured hernia of umbilical cord and other two cases had associated patent vitellointestinal duct (PVID). All of the cases were managed successfully.

Hernia of Umbilical Cord: Report of Three Unusual Cases

Congenital hernia of umbilical cord is a less frequent entity in newborns and occasionally associated with other maladies. Herein, we report three cases of hernia of umbilical cord. First case was associated with in-utero evisceration of entire small bowel through the presumably ruptured hernia of umbilical cord and other two cases had associated patent vitellointestinal duct (PVID). All of the cases were managed successfully.

Orientational and Microstructural Evolution During Epitaxial Growth of Cu on Si(001) by Sputter Deposition

Epitaxial Cu thin films have been grown on H-terminated Si(OOl) substrates at room temperature by D.C. ion-beam sputter deposition in ultrahigh vacuum. The development of orientation and microstructure during epitaxial growth from the initial stages of Cu growth up to Cu thicknesses of few hundred nm has been investigated. Analysis by in-situ reflection high energy electron diffraction, thin film x-ray diffraction, and plan-view and cross-sectional transmission electron microscopy indicates that the films are well textured with Cu(001)∥ Si(001) and Cu[100]∥ Si[110]. Interestingly, it is found that a distribution of orientations occurs at the early stages of Cu epitaxy on Si(001) surface, and that a (001) texture emerges gradually with increasing Cu thickness. The effect of silicide formation and deposition conditions on the crystalline quality of Cu epitaxy is also discussed.

Effect of Nitrogen Content on Interfacial Adhesion of the Ta/SiO2Interface

With the advent of copper metallization in interconnect structures, new barrier layers are required to prevent copper diffusion into the adjacent dielectrics as well as the underlying silicon. These barriers must not only prevent interdiffusion but also provide adequate adhesion to both the dielectric and copper. Ta and TaN have received considerable attention as barrier layers in copper metallization schemes. While much has been reported on their diffusion properties, little or no quantitative data exists on their adhesive properties. We present data on both the interface fracture energy and the subcritical debonding of ionmetal- plasma sputtered Ta and TaN films on thermal silicon oxide. Data is also presented showing the significant effect of interfacial chemistry, particularly varying nitrogen contents at the TaN/SiO2interface.

Bochdalek diaphragmatic hernia presenting with acute gastric dilatation

Congenital diaphragmatic hernia through the foramen of Bochdalek may present after infancy. A 21/2-year-old Malay girl presented with acute respiratory distress. Chest examination showed reduced chest expansion and decreased breath sounds on the left side. Chest radiograph showed a large "cyst" in the left chest, which was thought to be a lung cyst under tension. Tube thoracostomy resulted in clinical improvement. Results of a barium study showed that the cyst perforated by the thoracostomy tube was the stomach, which had herniated through a Bochdalek diaphragmatic defect. Surgical repair of the diaphragmatic defect and closure of the perforated stomach was performed successfully. Congenital diaphragmatic hernia should be included in the differential diagnosis of respiratory distress in young children. Nasogastric tube placement must be considered as an early diagnostic or therapeutic intervention when the diagnosis is suspected.

Lung abscess: an unusual presentation of congenital tracheoesophageal fistula without atresia

Tracheoesophageal fistula (TEF) without atresia is rare and usually presents with symptoms from birth. In this report, a 9-year-old boy presented with productive cough of 4 month's duration and was shown to have a right lung abscess seen on chest radiograph. His parents denied earlier respiratory symptoms or illnesses. Rigid bronchoscopy showed a fistulous opening of about 1 mm in diameter in the posterior wall of the trachea about 16 cm from the upper incisor teeth. Cannulation with a ureteral catheter demonstrated that the fistulous opening communicated with the esophageal lumen. The tracheoesophageal fistula was 1 cm long and was divided through a right supraclavicular incision. The postoperative period was uneventful, and the patient was discharged on the third postoperative day. This case demonstrated that TEF should be considered in any patient presenting with chronic respiratory problems even after a prolonged symptom-free period.

Serum prolactin bioactivity and immunoactivity in hyperprolactinaemic states

Serum prolactin concentrations were measured using a sensitive bioassay (Nb2 assay) and by radioimmunoassay in 11 patients with prolactin-secreting pituitary tumours (median serum immunoactive prolactin 5150 mU/L), and in 58 normal control subjects (median prolactin 190 mU/L). The mean ratio of serum prolactin bioactivity to immunoactivity was significantly lower in patients with prolactinomas than in normoprolactinaemic controls. Ten lactating women in the early post-partum period (median prolactin 3800 mU/L), studied as a model of physiological hyperprolactinaemia, also had reduced bioactivity to immunoactivity ratios. Overall, there was a significant negative correlation between bioactivity:immunoactivity ratio and serum immunoactive prolactin. The change in relative bioactivity of prolactin in serum samples from patients with prolactinomas and in women with physiological hyperprolactinaemia may reflect changes in the molecular heterogeneity of the hormone. Such changes may affect activity in both bioassays and radioimmunoassays.