Urinary flow rates in anterior hypospadias: Before and after repair and its clinical implication

Context

Hypospadias is a common urological anomaly which could be surgically corrected with good cosmetic results.

Aims

We aimed to detect changes in urinary flow parameters both before and after tubularised incised plate urethroplasty (TIPU) using uroflowmetry.

Settings and Design

Data collected were clinically implemented hypothesising the probability of urethrocutaneous fistula following stricture with Qmax variation.

Materials and Methods

This study is a prospective analysis done from December 2017 to October 2019. A total of 104 cases of anterior hypospadias were included in the study. A single surgical unit did TIPU. Pre-operative and post-operative uroflowmetry was done, and Qmax was recorded at 3 months, 6 months and 1 year after surgery. Mean Qmax was calculated for all intervals. A significant decrease in Qmax of a child (<2 standard deviation) was ascertained. Urethral calibration was done in those cases with a significant decrease of Qmax and analysed statistically.

Results

The mean age was 6.97 ± 2.41 years. Out of 104 children, 73 (70.2%) and 31 (29.8%) had distal and mid-shaft hypospadias, respectively. The pre-operative mean Qmax of the population was 6.20 ± 0.42 ml/s. Arithmetic mean Qmax at 3 months, 6 months and 1 year was 8.53 ± 0.42, 11.18 ± 0.47 and 13.71 ± 0.44 ml/s, respectively. On comparing the pre-operative with post-operative mean Qmax, a significant increase was found postoperatively (P < 0.0001). Twenty-four patients had significantly decreased Qmax value after 6 months. In these patients, follow-up urethral dilation was done with significant improvement.

Conclusion

The changes in maximum flow rate (Qmax) are suitable for use in routine follow-up. A significant decrease in Qmax over time indicates the onset of urethral stricture. These cases are to be intervened before venturing to redo urethroplasty.

To Determine the Genotyping of Fc-gamma Receptor FCGR2A Polymorphism as Genetic Susceptibility to Neonatal Sepsis: A Study from a Tertiary Center of North India

Background

Neonatal sepsis term is an infection of newborns <28 days of age. It is a common cause of death in developing countries. The receptor-gamma receptor FCGR2A has been shown to be associated with neonatal sepsis. It is an activating receptor found in many cell types such as monocytes, neutrophils, macrophages, platelets, and others. The receptor has a polymorphism (single-nucleotide polymorphism rs1801274) in its gene (FCGR2A) that encodes either a histidine (H) or arginine (R) at amino acid position 131. There are many studies showing the impact of these FCGR2A polymorphisms on sepsis. Our study aims to determine the prevalence of Fc-gamma receptor FCGR2A (rs1801274) polymorphism in neonatal sepsis and control in Eastern UP populations.

Patients and Methods

We conducted a cross-sectional descriptive study of 590 patients (310 healthy individuals and 280 sepsis patients) to determine polymorphisms in the CD32A coding region in neonates. All individuals were genotyped for a variant at position 131 of the FcγRIIA gene.

Discussion

In our study, the prevalence of FcγRIIa polymorphism is more in neonates with sepsis than in noninfected neonates. It was observed that the heterozygous allele (AG) were significantly increased in septic neonates when compared to the normal.

Conclusion

Our data indicate that FcγRIIA genotyping can be used as a marker of genetic susceptibility to sepsis.

BETTER PREDICTION OF SEVERITY IN ACUTE PANCREATITIS USING RADIOLOGICAL CRITERIA

Background: Acute pancreatitis is inflammation of the pancreas. Severe cases can lead to multi-organ dysfunction. So accurate prediction of severity is of great importance to improve survival. For the prediction of severity, there are several criteria. In this study, we have compared clinical criteria and imaging criteria to detect the severity of acute pancreatitis. In clinical criteria, we have taken Ranson criteria and BISAP(Bedside Index for Severity of Acute Pancreatitis) score. In imaging, we have taken MCTSI(Modified Computed Tomography Severity Index). Method: 50 patients (45 males & 05 females) in the age group of 15-65 years with a diagnosis of acute pancreatitis, admitted to a tertiary government hospital from July 2017 to June 2019 were included. BISAP score, Ranson criteria, and MCTSI were calculated for all the cases. Then Ranson and BISAP criteria were compared with MCTSI, deciding optimum cut-offs for these scorings, by obtaining the area under the curve analysis. Results: As per Atlanta classification, 31 cases were mild, 8 cases categorized as severe and 11 were grouped as moderately severe acute pancreatitis. Out of 50 cases, Pancreatic necrosis was found in 13 cases. Similarly, 15 patients landed in organ failure. The AUC for MCTSI was found to be consistently higher for predicting severe acute pancreatitis (0.958), pancreatic necrosis (0.942), organ failure (0.941) than Ranson criteria and BISAP criteria. The AUC for Ranson and BISAP criteria in predicting severe acute pancreatitis was 0.904 and 0.874, predicting pancreatic necrosis was 0.876 and 0.896 & in predicting organ failure was 0.881 and 0.880 respectively. Conclusion: MCTSI is more effective in detecting severe acute pancreatitis, organ failure, and pancreatic necrosis. So, the CECT scan is a better and simpler tool to detect the severity objectively for acute pancreatitis.

Modified Laparoscopic Excision of Choledochal Cyst: Technique and Early Results

BACKGROUND

Choledochal cyst is a common congenital anomaly requiring surgical treatment. Nowadays, laparoscopic excision is the preferred approach. We studied a modification in the classical laparoscopic approach to facilitate the dissection of a cyst.

MATERIALS AND METHODS

A prospective comparative study was done on 42 Type I choledochal cyst children. One group was operated by classical laparoscopic technique, while the other group was operated by modification of classical technique by deliberately opening the cyst wall and dividing the cyst into two hemi-cups, followed by dissection and excision. The intraoperative and postoperative parameters were assessed in both the groups.

RESULTS

The age, gender ratio, clinical presentation, and cyst diameter were comparable in both the groups. There was a significantly higher success rate (95.7% vs. 73.7%, P = 0.042) and lesser time for cyst excision (96.43 ± 12.15 vs. 120.91 ± 17.38 min P < 0.001) in the modified technique when compared to the classical technique. Further in three patients, it was possible to convert the classical procedure to a modified technique and complete the cyst excision. The postoperative outcomes were similar in both the groups.

CONCLUSION

The modified laparoscopic excision shortens the operative time with higher success rate and comparable short-term morbidity vis-a-vis classical laparoscopic technique.

Management of Mesenteric Cysts in Pediatric Population: Five-year Experience in Tertiary Care Center

Introduction To study the clinical features, diagnosis and treatment of mesenteric cysts in pediatric age group (< 15 years).

Materials and Methods This was a retrospective analysis which inculded 35 children diagnosed and treated for mesenteric cysts in the pediatric surgery department from January 2014 to January 2019. Patient’s data were retrieved from case sheets and analyzed. Patients with atleast one year follow-up were included in the study.

Results Thirty-five patients were included in the study. Twenty-one (60%) were males and fourteen (40%) were females. Mean age of presentation and surgery was 24 months. Twenty-six (74.2%) patients were managed by bowel resection, while 9 (25.7%) were managed by simple cystectomy. The average size of the cyst was 15 cm (ranging from 5 to 25 cm). Content of cysts was mostly chylous (82.9% cases). No recurrence was found throughout the follow-up period (1–2 years).

Conclusion Mesenteric cyst should be considered as a differential diagnosis in pediatric patients with acute or subacute intestinal obstruction and with or without a palpable lump in the abdomen. Mesenteric cysts can be managed surgically with favorable outcomes.

Role of Urinary Transforming Growth Factor Beta-B1 and Monocyte Chemotactic Protein-1 as Prognostic Biomarkers in Posterior Urethral Valve

Background:

Posterior Urethral Valves (PUV) are the most common cause of congenital LUT obstruction in males. Biomarkers of glomerular or tubular injury may be of particular value in predicting the need for surgical intervention or in tracing progression of chronic kidney disease. Measurement of biomarker in urine is relatively easy.

Aim:

To evaluate the changes in values of urinary Transforming Growth Factor Beta 1(TGF-B1) and Monocyte Chemotactic Protein (MCP-1) before and after valve ablation and its prognostic value in Posterior urethral valve.

Material and Method:

This prospective study was conducted from September 2016 to August 2018. The study group included 20 consecutive male babies with the diagnosis of PUV treated and followed up versus equal numbers of age matched control without any renal or urinary tract disease. Pre-operative urine samples were collected in Operative room. Cystoscopy and valve ablation was done. Follow up was done clinically by urinary stream and radiologically with VCUG. Follow-up was planned at 1 month, 3 months and 6 months following cystoscopic valve ablation. All collected urine samples were centrifuged at 10,000 rpm for 20 minutes. Supernatant was collected and two divided aliquots were stored at -200c to be thawed on the day of assay. Optical density of each well was recorded at 450 nm and 540 nm A p-value of <0.05 was considered to be statistically significant.

Result and Discussion:

Out of 20 cases of PUV, 14 (70%) cases were 1st born males of their family. The median age at the time of valve ablation in PUV cases was 2.5 (1.20-3.87) years.. Most common symptoms are fever and UTI. The preoperative median serum creatinine level was 1.65 mg/dl(1.22-2.42) pre-ablation, and fall significantly after ablation. Median eGFR level (calculated) was 25.635 (16.38-35.40) and after 6 months was 71.490 (45.44-96.93). Preoperative median MCP1 in PUV cases was 147.2 (82.8-512.5) and significant difference was also found in 1st, 3rd and 6th months after surgery (p<0.001, p=0.004 and p=0.002).Preoperative median TGF-B1 level was 197.8 pg/ml (79.9-386.4). There was no statistically significant change in TGF-B1 level at preoperative to 1 month and preop to 3 months after surgery but at 6 months after surgery the median TGF-B1 level significantly decreased as compared with preoperative TGF-B1 level.

Conclusion:

TGF β1 and MCP1 can be considered as prognostic urinary biomarkers in patients of PUV and can be used to specify and counsel patient's attendant regarding possibility of ESRD and need for further intervention.

Five-year experience of anorectal malformation with oesophageal atresia in tertiary care hospital

AIM

We had done this study for TEF with Anorectal malformation and TEF with no Anorectal malformation in terms of age, sex, surgical outcomes and mortality.

MATERIALS AND METHODS

This was a retrospective review of cases with clinical data (from April 2012 to April 2017). The participants of this study were 236 patients who had been diagnosed and managed for ARM. Among these patients, 25 patients associated with EA were selected as the subject patient group.

RESULTS

The incidence of tracheoesophageal fistula with ARM was 11.1%. The study has more male preponderance. All cases are of Type c except two cases of Type a. According to the classifications of ARMs, there were two cases with rectourethral fistula and eight cases with rectoperineal fistula and covered anus in the males. In females, there was a varied distribution of seven cases. There was one case (4%) presenting as a part of the Vertebral anorectal malformation cardiac tracheoesophageal renal and limb anomalies (VACTERL) association, which is the representative example of a complex anomaly. Most of the cases died due to cardiac problem and pneumonitis (due to delayed presentation).

CONCLUSION

The study concludes the experience of EA (±fistulae) with ARM, their distribution, incidence and outcome of the tertiary care centre.

Simplified Laparoscopic Suture Rectopexy for Idiopathic Rectal Prolapse In Children: Technique and Results

BACKGROUND

Laparoscopic suture rectopexy is safe and effective treatment option for pediatric rectal prolapse. We performed this study to compare the outcome of modified laparoscopic suture rectopexy (MLSR) versus Classical Laparoscopic suture rectopexy (CLSR).

MATERIAL AND METHODS

The study was conducted between June 2015 to May 2019 including all the patients with persistent rectal prolapse who underwent surgery managed by either MLSR (Group A) or CLSR (Group B). The groups were compared for constipation, operative time, blood loss, length of stay, postoperative complications.

RESULTS

19 patients from MLSR and 22 patients from CLSR were evaluated. The mean operative time in MLSR group was 41.5 ± 6.2 min which was significantly lesser than CLSR group with a mean operative time of 78.6 ± 14.2 (p = 0.001). The blood loss was also less in MLSR group compared to CLSR group (p = 0.013). At three months of follow up, the constipation was less in MLSR group compared to CLSR group (p = 0.041).

CONCLUSION

The modification makes the procedure technically easy, minimizes the chances of complications and retaining all the advantages of suture rectopexy.

LEVEL OF EVIDENCE

Level II.

Novel approach for the dissection of upper pouch during primary repair of esophageal atresia with tracheoesophageal fistula: Technique and results

BACKGROUND

We describe a technical modification to approach for dissection of proximal pouch in patients undergoing the primary repair of congenital Esophageal atresia with tracheoesophageal fistula (EA-TEF).

METHODS

A prospective comparative study was performed from January 2016 to December, 2019 including the patients who were undergoing primary repair of EA-TEF (Type C). The patients were divided into Group A (upper pouch dissection by classical approach) and Group B (technical modification). The two groups were compared for operative outcome and complications. Modified OSATS score was used to rate the performance of operators in two groups and were compared.

RESULTS

Total of 70 patients were included. In Group B, the mean operating time was less compared to Group A. The incidence of tracheal injury was also less when compared to previous data (p = 0.042). Mean OSATS score for flow of operation and overall performance was better in Group B (p = 0.002, p = 0.005). The OSATS score was also better for fifth and seventh case in Group B, proving its faster learning by trainee fellows.

CONCLUSION

The technical modification decreases chances of tracheal injury and shortens the learning curve for upper pouch dissection.

LEVEL OF EVIDENCE

Level III.

Is Magnetic Resonance Imaging Superior to Conventional Radiography in Neonates with Anorectal Malformation?

Introduction This study was conducted to evaluate the role of magnetic resonance imaging (MRI) in neonates with anorectal malformation (ARM).

Materials and Methods Newborns, referred to Pediatric Surgical Ward through General Surgery Outpatient Department and Emergency Department of Sir Sunderlal Hospital as a case of ARM, were included in the study. Unstable patients requiring urgent primary colostomy were excluded from the study. Forty neonates with ARM and 20 neonates having no ARM were included in the study ( 2 years, i.e., conducted between September 2018 and July 2020). The included patients were evaluated clinically and were subjected to an invertogram (after 24 hours of delivery), which is conventional radiography. Further, MRI was performed using 1.5 T superconductive system; 5 to 6 mm contiguous sections were obtained using a head or a body coil according to the size of the infant patient to obtain images with sharp anatomical detail: Sagittal, coronal, and axial conventional spin-echo T1-weighted images of the pelvic region were obtained in all patients, with perpendicular coronal plane and the axial plane parallel to pelvic floor.

Results The majority of patients (60%) were referred on day 3 of birth and rest were referred after 3 days of birth. Conventional radiography, that is, invertogram was done in all study population. Sixty per cent of the total included patients had supralevator location of rectal pouch. Conventional radiography was detected to be low type of ARM—all had infralevator position of rectal pouch in MRI, but 60% of the intermediate had supralevator level and all high abnormalities had supralevator level. These distribution anomalies were statistically significant. The levator ani length index and external anal sphincter length index were also compared and found to be thickest in intermediate type, thick in low types, and thin in high type of abnormalities, which is an added advantage of MRI over radiography.

Conclusion Preoperative assessment of ARM with MRI gives useful information regarding type of malformation as well as sphincter muscle and associated malformations. Large sample size was needed for future landmark in the field of ARM.

Development of a biomarker of efficacy in second-line treatment for lymphangioma of the tongue: a pilot study

Lymphangioma of the tongue is a rare lymphatic malformation, and various authors have reported the successful use of sirolimus for its treatment. However, the safety of sirolimus in children needs further evaluation so that those who do not respond are not necessarily exposed to its potential adverse effects. We hypothesised that assessment of lymphangiogenesis can be used to predict whether the patient will respond to sirolimus, so we organised a prospective study after ethics committee approval had been given. After clinical and histological diagnoses of lymphangioma of the tongue had been confirmed, 16 patients were given sirolimus 0.8mg/day in three divided doses. Clinical response was assessed and compared with lymphatic microvessel density (LMVD), which was calculated immunohistochemically using the monoclonal antibody D2-40 as the lymphatic endothelial marker. Nine patients responded well, five partially, and two failed to respond. Mean (SD) LVD among the good responders was 21.00 (3.74), whereas among non-responders it was 8.00 (4.24). There was a significant difference in mean LVD between good responders, partial responders, and non-responders (p=0.04). Sirolimus is effective in treating children with lymphangioma of the tongue, and lymphangiogenesis is a useful therapeutic predictive marker.

Light metal decorated graphdiyne nanosheets for reversible hydrogen storage

The sensitive nature of molecular hydrogen (H₂) interaction with the surfaces of pristine and functionalized nanostructures, especially two-dimensional materials, has been a subject of debate for a while now. An accurate approximation of the H₂ adsorption mechanism has vital significance for fields such as H₂ storage applications. Owing to the importance of this issue, we have performed a comprehensive density functional theory (DFT) study by means of several different approximations to investigate the structural, electronic, charge transfer and energy storage properties of pristine and functionalized graphdiyne (GDY) nanosheets. The dopants considered here include the light metals Li, Na, K, Ca, Sc and Ti, which have a uniform distribution over GDY even at high doping concentration due to their strong binding and charge transfer mechanism. Upon 11% of metal functionalization, GDY changes into a metallic state from being a small band-gap semiconductor. Such situations turn the dopants to a partial positive state, which is favorable for adsorption of H₂ molecules. The adsorption mechanism of H₂ on GDY has been studied and compared by different methods like generalized gradient approximation, van der Waals density functional and DFT-D3 functionals. It has been established that each functionalized system anchors multiple H₂ molecules with adsorption energies that fall into a suitable range regardless of the functional used for approximations. A significantly high H₂ storage capacity would guarantee that light metal-doped GDY nanosheets could serve as efficient and reversible H₂ storage materials.

Manipulating energy storage characteristics of ultrathin boron carbide monolayer under varied scandium doping

We report, for the first time we believe, a detailed investigation on hydrogen storage efficiency of scandium (Sc) decorated boron carbide (BC₃) sheets using spin-polarized density functional theory (DFT).

Adsorption mechanism of graphene-like ZnO monolayer towards CO₂ molecules: enhanced CO₂ capture

This work aims to efficiently capture CO2 on two-dimensional (2D) nanostructures for effective cleaning of our atmosphere and purification of exhausts coming from fuel engines. Here, we have performed extensive first principles calculations based on density functional theory (DFT) to investigate the interaction of CO2 on a recently synthesized ZnO monolayer (ZnO-ML) in its pure, defected and functionalized form. A series of rigorous calculations yielded the most preferential binding configurations of the CO2 gas molecule on a ZnO-ML. It is observed that the substitution of one oxygen atom with boron, carbon and nitrogen on the ZnO monolayer resulted into enhanced CO2 adsorption. Our calculations show an enriched adsorption of CO2 on the ZnO-ML when substituting with foreign atoms like B, C and N. The improved adsorption energy of CO2 on ZnO suggests the ZnO-ML could be a promising candidate for future CO2 capture.

Hydrogen storage properties of light metal adatoms (Li, Na) decorated fluorographene monolayer

Owing to its high energy density, the potential of hydrogen (H2) as an energy carrier has been immense, however its storage remains a big obstacle and calls for an efficient storage medium. By means of density functional theory (DFT) in spin polarized generalized gradient approximation (GGA), we have investigated the structural, electronic and hydrogen storage properties of a light alkali metal (Li, Na) functionalized fluorographene monolayer (FG). Metal adatoms bind to the FG with significantly high binding energy, much higher than their cohesive energies, which helps to achieve a uniform distribution of metal adatoms on the monolayer and consequently ensure reversibility. Due to a difference of electronegativities, each metal adatom transfers a substantial amount of its charge to the FG monolayer and attains a partial positive state, which facilitates the adsorption of multiple H2 molecules around the adatoms by electrostatic as well as van der Waals interactions. To get a better description of H2 adsorption energies with metal-doped systems, we have also performed calculations using van der Waals corrections. For both the functionalized systems, the results indicate a reasonably high H2 storage capacity with H2 adsorption energies falling into the range for the practical applications.

Is a foetus developing in a sterile environment?

Novel findings in microbiology question the long-standing paradigm that a healthy pregnancy implies a sterile uterus. It now seems that the placenta is frequently colonized with bacteria, and a placental microbiome has been identified. Recent literature findings are summarized here, and an attempt is made to separate pathological bacterial presence from a naturally occurring microbiome.

Endophthalmitis caused by Acinetobacter baumanni: a case series

PURPOSE

To profile the etiology, clinical outcomes and drug sensitivity patterns in endophthalmitis caused by Acinetobacter baumanni.

METHODS

Retrospective analysis of all the cases of Acinetobacter baumanni endophthalmitis presenting to tertiary referral care ophthalmic hospital in Eastern India from January 2009 to December 2011 were done.

RESULTS

A total of four cases were included in the study. Out of the four cases one was post traumatic and the rest were post cataract surgery. All the cases underwent vitreoretinal surgical intervention followed by intravitreal antibiotics. A. Baumanni was isolated from vitreous in all the cases. Among all the drugs tested bacteria were found sensitive to ciprofloxacin (100 %) whereas all tested resistant to ceftazidime. Out of the four cases one had to be eviscerated, another developed retinal detachment post vitrectomy, one was phthisical at final followup, and only one patient achieved a vision of 20/200 with clear media and attached retina at final visit.

CONCLUSION

A. Baumanni is a very rare cause of endophthalmitis with poor visual and anatomical outcomes. Ciprofloxacin should be considered as first the line intravitreal antibiotic.

Quality of induced sputum using a human-powered nebuliser in a mobile human immunodeficiency virus testing service in South Africa

OBJECTIVES

To investigate the quality of induced sputum samples using a human-powered (HPN) and an electric-powered nebuliser (EPN).

METHODS

For each participant two sputum samples were induced using the HPN and the EPN. The sequence of the two nebulisers was allocated at random. The proportion of good quality sputum according to different assessment criteria was compared using an exact McNemar test. The difference in time to expectoration was compared using the Wilcoxon matched-pairs signed-rank test.

RESULTS

A total of 123 individuals were eligible for the study. Nine individuals refused to participate and five were unable to produce a sputum sample. The proportion of good quality sputum was higher among sputum samples induced by the HPN compared to those obtained using the EPN. The median time to produce a sputum sample was 2.2 min (IQR 1.13-4.1) for the HPN and 2.5 min (IQR 1.4-4.1) for the EPN.

CONCLUSION

The HPN induced good quality sputum within 3 min. The device operates without electricity and is suitable not only for remote clinics with unreliable electricity, but also for mobile services and community-based intensified tuberculosis (TB) case finding. Further research needs to investigate the yield of TB in sputum samples induced by the HPN.

Loss of Helicobacter pylori hemagglutination with serial laboratory passage and correlation of hemagglutination with gastric epithelial cell adherence

Adherence of Helicobacter pylori to gastric epithelial cells is thought to be important in the pathogenesis of infection and may be essential to maintain lifelong colonization. However, the factors responsible for adherence to gastric epithelial cells in vivo have not been characterized, and the significance of adherence to standard epithelial cell lines is unclear. Hemagglutination is also thought to be important in H. pylori adherence. However, no studies have clearly linked H. pylori hemagglutination or adherence to cultured epithelial cells to primary gastric epithelial cell adherence. Furthermore, it is not clear whether laboratory strains which have undergone multiple passages lose potential colonization factors. In this study, we examined the effect of serial laboratory passage on hemagglutination and correlated the hemagglutination characteristics of H. pylori strains to primary gastric cell adherence. Variable expression of hemagglutination was seen with serial laboratory passage of 15 strains. After 100 serial laboratory passages, all strains had lost hemagglutination activity. Hemagglutination was seen in association with adherence to primary gastric cells in vitro isolated from 2 patients. An association with ultrastructural intimate adherence was seen with HEp-2 cells, but not with gastric adenocarcinoma cells. Ultrastructural adherence was seen in corresponding antral biopsies of patients whose strains were hemagglutination positive, but hemagglutination was not associated with gastric inflammation. These data indicate that H. pylori hemagglutination is lost with serial passage and that hemagglutination may play a role in the attachment of H. pylori to gastric epithelial cells, but the role of adherence to chronic gastric inflammation is unclear.

Ultrasonographic evaluation of common duct diameter in pre and post cholecystectomy patients

Thirty four patients with gall bladder disease and normal common duct were investigated prospectively by ultrasonography just before cholecystectomy and at periodic intervals of 1 months, 2 months, 3 months and once in 4-6 months after cholecystectomy. The pre and post cholecystectomy common duct diameters were measured at each visit and compared with each other to determine the statistical significance. No significant change (p > 0.05) occurred in common duct diameter following cholecystectomy.

Stool microflora in extremely low birthweight infants

AIM

To serially characterise aerobic and anaerobic stool microflora in extremely low birthweight infants and to correlate colonisation patterns with clinical risk factors.

METHODS

Stool specimens from 29 infants of birthweight <1000 g were collected on days 10, 20, and 30 after birth. Quantitative aerobic and anaerobic cultures were performed.

RESULTS

By day 30, predominant species were Enterococcus faecalis, Escherichia coli, Staphylococcus epidermidis, Enterbacter cloacae, Klebsiella pneumoniae, and Staphylococcus haemolyticus. Lactobacillus and Bifidobacteria spp were identified in only one infant. In breast milk fed (but not in formula fed) infants, the total number of bacterial species/stool specimen increased significantly with time (2.50 (SE 0.34) on day 10; 3.13 (0.38) on day 20; 4.27 (0.45) on day 30) as did quantitative bacterial counts; Gram negative species accounted for most of the increase. On day 30, significant inverse correlations were found between days of previous antibiotic treatment and number of bacterial species (r=0.491) and total organisms/g of stool (r=0.482). Gestational age, birthweight, maternal antibiotic or steroid treatment, prolonged rupture of the membranes, and mode of delivery did not seem to affect colonisation patterns.

CONCLUSIONS

The gut of extremely low birthweight infants is colonised by a paucity of bacterial species. Breast milking and reduction of antibiotic exposure are critical to increasing fecal microbial diversity.

Epidermal growth factor up-regulates sodium-glucose cotransport in enterocyte models in the presence of cholera toxin

BACKGROUND

Sodium-glucose cotransport by enterocytes is key to the successful implementation of oral rehydration in diarrhea. Confluent, differentiated Caco-2 cells have enterocyte-like characteristics. We have previously shown that short-term incubation of isolated rat jejunal enterocytes with epidermal growth factor (EGF) results in the up-regulation of sodium-glucose cotransport. The aim of this study was to examine the effect of EGF on Caco-2 cells in the presence of cholera toxin.

METHODS

Caco-2 cells grown on tissue culture dishes were used for glucose and sodium uptake studies and cells were grown on polycarbonate membranes for transport examinations. Effects of EGF on the kinetic parameters of sodium-glucose contransporter, thymidine transport, and on the activity of Na+/K(+)-ATPase were examined. The efficacy of basolateral vs apical EGF on sodium and glucose transport was compared after incubation of the monolayers with 10 nmol/L of cholera toxin.

RESULTS

EGF increased both glucose and sodium uptake and transport, and we observed a simultaneous increase in the activity of Na+/K(+)-adenosine triphosphatase (ATPase). Kinetic studies performed on brush-border membrane vesicles prepared from EGF-incubated confluent monolayers and on intact cells showed an increase in the maximum velocity but not the Michaelis constant, suggesting increased availability of transporters rather than conformational change. This effect was seen within minutes in both of the two putative transporters, high-affinity, low-capacity and low-affinity, high-capacity. There was no acute effect on thymidine uptake. Studies in the presence of cholera toxin demonstrated a significant up-regulation in sodium-glucose cotransport when EGF was applied from the basolateral side; the increase was smaller but significant with apical application.

CONCLUSIONS

Differentiated Caco-2 cells have two kinetically distinct sodium-glucose cotransporters. Short-term incubation of Caco-2 cells with EGF resulted in an up-regulation of sodium-glucose cotransport and subsequent increase in Na+/K(+)-ATPase activity. The effect of basolaterally applied EGF was more significant with or without incubation with cholera toxin. The early effect of EGF on glucose and sodium cotransport may have important therapeutic implications in diarrhea and dehydration states. The in vitro model described here uses a homogeneous cell population and provides a versatile system for uptake and transport studies.

Role of glutamine in bacterial transcytosis and epithelial cell injury

BACKGROUND

L-Glutamine is the principal energy source for small intestinal enterocytes. Diminution of intestinal function, mucosal atrophy, and increased bacterial translocation have been noted during total parenteral nutrition (TPN). In a rat model of glutamine starvation, we previously showed that luminal glutamine is essential for optimal intestinal function. In this study, we examined the effect of apical vs basolateral glutamine on bacterial translocation in a Caco-2 cell culture system and bacteria-induced tissue injury in a weanling rabbit ileal loop model.

METHODS

Caco-2 cells were grown in a transwell system. After confluence, apical and basolateral chambers received defined media, and glutamine deprivation was carried out over a 4- to 48-hour period. Escherichia coli transcytosis and structure/function studies were then performed. In a second series of experiments, the effect of intraluminal glutamine supplementation was evaluated in an E. coli-induced tissue injury model in weanling rabbit ileal loops.

RESULTS

Expression of disaccharidases, glucoamylase, and Na+/K(+)-adenosine 5'-triphosphatase (ATPase) were significantly reduced when cells were deprived of glutamine from the apical side, and there was increased bacterial translocation across the monolayer. Transepithelial epithelial resistance (TEER) across the monolayer was also reduced in the glutamine-free cultures. Glutamine replenishment over 24 to 48 hours restored the original functions. Basolateral deprivation had a smaller effect on the Caco-2 cells. Typical necrotic mucosal injury caused by E. coli in the ileal loops was blocked by co-infiltration of the loops with glutamine.

CONCLUSIONS

This study demonstrates for the first time that the supply of glutamine from the apical side is of critical importance for maintaining optimal structure and function of the enterocytes. The effects are not acute or energy related. These observations have important clinical implications in the management of patients under critical care, including premature infants and patients receiving TPN, for whom lack of glutamine from the luminal side could produce mucosal dysfunction, resulting ultimately in severe atrophic/necrotic complications.

Vibrio cholerae O1 can assume a chlorine-resistant rugose survival form that is virulent for humans

Vibrio cholerae can shift to a "rugose" colonial morphology associated with expression of an amorphous exopolysaccharide that promotes cell aggregation. Flow cytometric studies indicated that up to 3% of particles in rugose cultures represented aggregates of >5 bacterial cells. Rugose variants of our test strains displayed resistance to killing by chlorine, with viable cells persisting for >30 min in 2 mg/L free chlorine; strains also showed resistance to killing by complement-mediated serum bactericidal activity. Six volunteers fed 10(6) cfu of a rugose variant of V. cholerae O1 El Tor Inaba N16961 developed symptoms typical of cholera, with a mean diarrheal stool volume of 2.2 L (range, 1.4-4.3). Isolates recovered from the stool of infected volunteers retained the rugose phenotype. The data suggest that rugose strains cause human disease. The role of these strains in the epidemiology of cholera remains to be determined.

Escherichia coli transcytosis in a Caco-2 cell model: implications in neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a serious gastrointestinal disorder of preterm infants. Other than an association with prematurity and gastrointestinal feeding, no single factor or mechanism has been consistently linked to this disease. We have previously demonstrated that Escherichia coli isolates obtained from the stool of infants with NEC caused NEC-like injury in a weanling rabbit ileal loop model; this injury, in turn, could be blocked by coinfection with selected Gram(+) bacteria (Enterococcus faecium) isolated from asymptomatic controls. Using Caco-2 cells in a trans-well system, we now demonstrate that the same E. coli isolates can cross epithelial cell monolayers in the absence of ultrastructural change or damage. These results with E. coli contrast with those seen with Salmonella typhimurium, which passed through the monolayer at a higher rate and were associated with striking ultrastructural damage. Transcytosis of E. coli was reduced 3-5-fold in the presence of E. faecium previously shown to block NEC-like injury in the loop model. There was a mild increase in the rate of E. coli transcytosis when studies were conducted with younger, undifferentiated cells; these immature cells had no brush border, had decreased production of brush border-specific enzymes, but retained well defined tight junctions, as demonstrated by transepithelial electrical resistance and electron microscopy. A further reduction/ complete blockage of E. coli transcytosis was observed when E. faecium was used as the coinfectant in studies with these undifferentiated cells. We hypothesize that the ability of E. coli to cross epithelial cell layer is a critical initial step in the cascade of events which lead ultimately to NEC; blockage or reduction in E. coli transcytosis in the presence of certain Gram(+) organisms may play a significant role in prevention of NEC.

Clinical and immunologic characteristics of Vibrio cholerae O139 Bengal infection in North American volunteers

Vibrio cholerae O139 Bengal has recently emerged as a cause of epidemic cholera in Asia. To evaluate clinical and immunologic responses to infection, V. cholerae O139 Bengal AI1837 was administered to healthy adult North American volunteers. Two of 4 persons ingesting 10(4) cfu became ill (incubation period, 48 h; mean diarrheal stool, 1873 g), as did 7 of 9 persons receiving 10(6) cfu (incubation period, 28 h; mean diarrheal stool, 4548 g). Ill volunteers did not demonstrate a vibriocidal antibody response to the challenge strain or other V. cholerae. Three months later, volunteers were rechallenged with the homologous O139 Bengal strain. Only 1 of 6 persons who had been ill on initial challenge had diarrhea, compared with 11 of 13 controls (P = .01; protective efficacy = 80%). V. cholerae O139 Bengal can cause severe diarrhea typical of cholera, with clinical characteristics and a dose-response similar to those seen with V. cholerae O1 El Tor. A moderately high level of protection against subsequent disease is provided by initial clinical infection.

The capsule and O antigen in Vibrio cholerae O139 Bengal are associated with a genetic region not present in Vibrio cholerae O1

Vibrio cholerae O139 Bengal, although closely related to V. cholerae O1 El Tor, produces a polysaccharide capsule and has a distinct O antigen. We have identified a chromosomal region of at least 11 kb, as defined by three TnphoA mutations, that is required for the expression of both polysaccharides. Electron microscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis show that these TnphoA mutants have lost the abilities both to express capsule and to produce lipopolysaccharide beyond the core oligosaccharide. Reactivity with O139 typing serum and resistance to serum are also lost in the mutants. DNA probes for this region do not hybridize with O1 V. cholerae but do react with other vibrios, implying that the region was recently acquired.

Ribosomal RNA patterns identify additional strains of Campylobacter jejuni and C. coli among isolates serotyped by heat-stable and heat-labile antigens

Heat-stable (HS, O-antigen) and heat-labile (HL) serotyping are the most common methods used to type Campylobacter jejuni and C. coli for epidemiologic purposes. In this study, we conducted RRNA analysis to differentiate strains of C. jejuni and C. coli that had been serotyped by use of the passive hemagglutination (heat-stable) and slide agglutination (heat-labile) methods. Ribotyping of isolates within HS and HL serotypes revealed further discrimination of strains. Four ribotypes were identified by Pvu II and Pst I digests of eight HS serotype-34 isolates. Ribotyping also differentiated strains within HL serotypes. Ribotyping also was conducted on 10 representative isolates of C. jejuni and C. coli isolated from an infant macaque. The eight ribotypes confirmed previous results of serotyping and other phenotypic analyses, which indicated that the infant was repeatedly reinfected with different strains of C. jejuni and C. coli. Results of the study indicated that ribotyping is a sensitive molecular marker for distinguishing strains of C. jejuni and C. coli. Furthermore, some isolates with similar ribotype patterns had variability in their HS and HL serotypes.

Endemic necrotizing enterocolitis: lack of association with a specific infectious agent

We conducted a comprehensive analysis of bacterial, parasitic and viral agents present in stool samples of 23 necrotizing enterocolitis cases and 23 matched and 10 random controls. Enterococcus spp., Staphylococcus epidermidis, and Escherichia coli were the most common aerobic bacterial species isolated. Astrovirus was identified in a stool sample from one control. Eight infants were bacteremic; in 7 of 8 the same organism was also present in the stool. No one bacterial species or strain (as identified by plasmid profile analysis) was associated with occurrence of illness. Plasmid analysis further suggested that each infant was colonized with his or her own distinctive aerobic bacterial flora. With the exception of isolates from two control patients which hybridized with a probe for diffuse adherence, no diarrheagenic E. coli was identified. Five (45%) of 11 case infants were colonized with coagulase-negative staphylococci (all S. epidermidis) that produced delta-hemolysin in vitro, as compared with 13 (87%) of 15 control infants. Necrotizing enterocolitis was not associated with an increased ability to ferment carbohydrate, as measured by in vitro beta-galactosidase activity. Our data do not support the hypothesis that endemic necrotizing enterocolitis in our institution is caused by a single infectious agent, nor was there evidence that previously proposed virulence mechanisms such as production of delta-hemolysin or increased in vitro carbohydrate fermentation play a critical role in disease occurrence.

Vibrio cholerae O139 synonym bengal is closely related to Vibrio cholerae El Tor but has important differences

Although Vibrio cholerae O139 synonym Bengal strains, from the current epidemics in India and Bangladesh, are closely related to seventh-pandemic strains, as shown by multilocus enzyme electrophoresis, Bengal strains are encapsulated and portions of the O1 antigen biosynthetic complex genes found in O1 strains are altered or lacking. Encapsulated Bengal strains showed resistance to killing by normal human serum. The presence of the capsule suggests the potential for bloodstream invasion in susceptible hosts and has profound implications for vaccine development.

Occurrence of necrotizing enterocolitis may be dependent on patterns of bacterial adherence and intestinal colonization: studies in Caco-2 tissue culture and weanling rabbit models

Necrotizing enterocolitis (NEC) is one of the leading causes of death in neonatal intensive care units. The underlying pathophysiology of NEC is poorly defined, although there is a suggestion that bacterial agents play an important role in the process. In this study, we evaluated bacterial isolates from 17 NEC cases and matched asymptomatic control infants. Isolates from NEC patients were no more likely than control isolates to be adherent to enterocytes, as assessed by a Caco-2 cell tissue culture model. Adherent Escherichia coli isolates, from both NEC cases and controls, were able to cause pathologic changes typical of NEC in a weanling rabbit ileal loop model. Adherence of E. coli strains to Caco-2 cells, and subsequent production of disease in weanling rabbits, could be blocked by coinfection with Gram-positive isolates from control children. In contrast, in three of four instances, adherent E. coli from NEC cases retained their adherence and caused illness in rabbits when coinfected with Gram-positive isolates from the homologous child. Our data suggest that patterns of intestinal adherence, as influenced by the underlying intestinal microbial ecology, play a role in the pathophysiology of NEC.

Human immune response to Campylobacter jejuni proteins expressed in vivo

Campylobacter jejuni 81-176 grown in vivo in rabbit ileal loops expresses novel proteins that are not expressed under standard laboratory culture conditions. A new protein with a molecular mass of ca. 180 kDa is expressed at 14, 24, and 48 h of infection. Three other proteins, with molecular masses of ca. 66, 43, and 35 kDa, are overexpressed during different phases of infection. Expression of these proteins stops immediately during the first passage in laboratory media, and they do not elicit a human immune response. Two other proteins, with molecular masses of ca. 84 and 47 kDa, expressed 48 h after infection can be identified by using convalescent sera from human volunteers who were immune to C. jejuni infection upon rechallenge; these proteins were not visualized on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels by Coomassie blue staining or silver staining. Antibodies to the 84- and 47-kDa proteins are of the immunoglobulin G class. Both preinfection and convalescent human sera react strongly to the C. jejuni flagellin (a 58-kDa protein), suggesting the presence of cross-reactive antibodies to this protein in healthy humans. Major outer membrane protein and flagella may play a role in providing protection against C. jejuni disease, but our data suggest that there are other proteins expressed only during in vivo growth of the organism that elicit a strong immune response in human C. jejuni infections.

Non-O1 Vibrio cholerae NRT36S produces a polysaccharide capsule that determines colony morphology, serum resistance, and virulence in mice

Non-O1 Vibrio cholerae produced two distinct colony types, designated as opaque and translucent. NRT36S, a clinical isolate shown to be virulent in volunteers, produced predominantly opaque colonies, but translucent colonies appeared on subculture. Opaque variants were recovered exclusively following exposure to normal human serum or animal passage. A nonreverting translucent mutant of NRT36S, JVB52, was isolated following mutagenesis with the transposon Tn5 IS50L::phoA (TnphoA). Only translucent colonies were produced by a nonpathogenic environmental isolate, A5. Electron microscopic examination of the opaque form of NRT36S revealed thick, electron-dense, fibrous capsules surrounding polycationic ferritin-stained cells. The ferritin-stained material around translucent NRT36S or A5 was patchy or absent. JVB52 had a thin but contiguous capsular layer. The amount of ferritin-stained capsular material correlated with the amount of surface polysaccharide determined by phenol-sulfuric acid assay: opaque NRT36S had approximately three times as much polysaccharide as translucent NRT36S or A5 and four times as much as JVB52. The encapsulated, opaque variant of NRT36S was protected from serum bactericidal activity, while translucent non-O1 V. cholerae was readily killed. The encapsulated form also had increased virulence in mice. Our data provide the first indication that non-O1 V. cholerae strains can have a polysaccharide capsule. This capsule may be important in protecting the organism from host defenses and may contribute to the ability of some non-O1 V. cholerae strains to cause septicemia in susceptible hosts.

Development of an in vitro model for study of non-O1 Vibrio cholerae virulence using Caco-2 cells

Non-O1 Vibrio cholerae strains have been reported as a causative agent of diarrhea throughout the world. We recently reported that non-O1 V. cholerae strains cause diarrhea in human volunteers. In this study we evaluated the virulence of three strains of non-O1 V. cholerae in a Caco-2 cell adherence assay by light and electron microscopy. A-5 is an environmental isolate which failed to colonized volunteers and did not cause diarrhea. It exhibited low numbers of organisms adherent to Caco-2 cells, leaving the microvilli intact. Strain 2076-79, isolated from a patient with diarrhea, colonized human volunteers without producing disease. It adhered to Caco-2 cells in moderate numbers without producing any damage to the microvilli. Strain NRT36S, a clinical isolate, colonized human volunteers and produced significant diarrhea disease. This strain adhered in very large numbers to Caco-2 cells and caused damage to the brush borders. Membrane-bound bacteria were also seen within the cytoplasm of these cells. Scanning electron microscopy confirmed the generalized adherence of NRT36S to the microvilli of Caco-2 cells. The three strains did not appear to compete with each other for binding sites on Caco-2 cells and were not adherent when assays were conducted at 4 degrees C. Our results with strains A-5, 2076-79, and NRT36S correlate well with observations in human volunteer studies, suggesting that Caco-2 cells provide an appropriate in vitro system for further investigation of the pathogenesis of non-O1 V. cholerae gastroenteritis.

Evidence of reinfection with multiple strains of Campylobacter jejuni and Campylobacter coli in Macaca nemestrina housed under hyperendemic conditions

A prospective bacteriologic study of 18 infant pig-tailed macaques (Macaca nemestrina) housed in a nursery facility in which Campylobacter spp. are endemic was undertaken to determine the epidemiology of infection and reinfection. The isolates of Campylobacter jejuni and C. coli cultured from 8 of the 18 infants were characterized by serotyping, DNA hybridization, and polyacrylamide gel electrophoresis protein profiles. The chronology of infection was indicative of multiple reinfections with different strains of C. jejuni and C. coli during the 12-month study of each infant. The duration of infection with a particular strain was 3 to 4 weeks. Infants were also infected with nalidixic acid-resistant campylobacters. These observations indicated that long-term infections under endemic conditions are caused by continual reinfection. C. jejuni or C. coli infection correlated with diarrhea in 5 of the 18 infants at 1 to 4 months of age.

Defective transport of hemagglutinin-neuraminidase glycoprotein of bovine parainfluenza-3 virus in interferon treated cell

A defective transport of bovine parainfluenza-3 virus (PI-3V) hemagglutinin-neuraminidase (HN) glycoprotein was evidenced in interferon (IFN)-treated bovine turbinate (BTu) cells. Indirect immunofluorescence performed with monoclonal antibody to PI-3 HN glycoprotein demonstrated accumulation of this protein in the perinuclear cytoplasm of IFN-treated cells. Untreated, infected control cells had a generalized widespread fluorescence. Unfixed control cells showed a uniform surface fluorescence in contrast to a few specs of fluorescence on the plasma membrane of IFN-treated cells. Electron microscopic localization of HN protein was done by immuno-gold ultrastructural cytochemistry. Untreated cells had uniform gold label on the plasma membrane and around the budding virus particles with no label in the cytoplasm. In IFN-treated cells, however, there was an accumulation of gold particles in the cytoplasm with only a few particles on the cell surface. Quantitative analysis of HN protein on the cell surface by solid phase radioimmune-assay revealed a greater amount of this protein on the surface of control cells, than those on the IFN-treated cells.

Effect of cloned human interferon-alpha 2a on bovine parainfluenza-3 virus. Brief report

Pretreatment of bovine turbinate (BTu) cells with cloned human interferon (IFN)-alpha 2a reduced the yield of infectious bovine parainfluenza-3 virus (PI-3 V). Intracellular synthesis of HN glycoprotein was reduced on postinfection day 1 (PID 1), but it recovered to normal levels subsequently. However, reduction of this protein persisted in the released virus through PID 2. Thin section electron microscopy demonstrated a drastically reduced release of mature virions and an accumulation of viral nucleocapsids inside the cytoplasm on PID 2. These results suggest that cloned human IFN-alpha 2a affects the glycoprotein synthesis, and morphogenesis of bovine PI-3 V, and thus inhibits the release of viral particles from treated cells.

Structural proteins of bovine parainfluenza-3 virus

Six structural proteins of bovine parainfluenza-3 virus (PI-3V) labeled with [35S]-methionine could be resolved by polyacrylamide gel electrophoresis (PAGE). Five structural proteins of this virus had been previously reported. The 6 proteins found in this study were: L, a 180,000 (180 kD) molecular weight (MW) large protein; P, 83 kD phosphoprotein; HN, 69 kD hemagglutinin-neuraminidase glycoprotein; NP, 66 kD nucleocapsid protein; F, 55 kD fusion glycoprotein; and M, 38 kD matrix protein. Selective labeling with [2-3H]-mannose revealed only HN and F glycoprotein bands. A cellular actin protein (43 kD), associated with many enveloped viruses, was also found as a seventh protein in bovine PI-3V.