Syndromic congenital diaphragmatic hernia: Current incidence and outcome. Analysis from the congenital diaphragmatic hernia study group registry

BACKGROUND

The aim of this study was to describe the incidence of Congenital Diaphragmatic Hernia, CDH, associated with known or clinically suspected syndromes, and the postnatal outcomes from a large database for CDH.

METHODS

Data from the multicenter, multinational database on infants with CDH (Congenital Diaphragmatic Hernia Study Group Registry) born from 1996 to 2020 were analyzed. Patients with known or suspected syndromes were grouped and outcome data were analyzed and compared to those without syndromic features.

RESULTS

A total of 12,553 patients were entered in the registry during the study period, and 421 had reported known syndromes, representing 3.4% of all CDH cases in the registry. A total of 50 different associated syndromes were reported. In addition to those with clinically suspected genetic conditions, a total rate of genetic syndromes with CDH was 8.2%. The overall survival to discharge for syndromic CDH was 34% and for non-syndromic CDH was 76.7%. The most common were syndromes Fryns syndrome (19.7% of all syndromes, 17% survival), trisomy 18 or Edward syndrome (17.5%, 9% survival), trisomy 21 or Down syndrome (9%, 47% survival), trisomy 13 or Patau syndrome (6.7%, 14% survival), Cornelia de Lange syndrome (6.4% of all syndromes, 22% survival) and Pallister-Killian syndrome (5.5% of all syndromes, 39.1% survival). In addition, 379 cases had reported chromosomal anomalies and 233 cases had clinically suspected syndromes, based on two more dysmorphic features or malformations in addition to CDH, but without molecular diagnosis. The syndromic CDH group had lower birth weight and gestational age at birth and increased incidence of bilateral CDH (2.9%) and rates of non-repair (53%). The length of hospital stay was longer, and larger number of patients needed O2 at 30 days. Extracorporeal life support was used only in 15% of the cases. Those who underwent surgical repair had survival to discharge rates of 73%.

CONCLUSION

Syndromic CDH is rare and only 3.4% of the reported cases of CDH have a known syndrome or association, but, if including patients with two dysmorphic features malformations, in addition to CDH, altogether as many as 8.2% have a diagnosed or suspected genetic condition. These children have with lower survival rates. Given higher rates of non-repair and decreased extracorporeal life support use, along with a high early mortality, decision-making regarding goals of care clearly influences outcomes. Survival varies depending on the genetic cause. Early genetic diagnosis is important and may influence the decision-making.

Virtual Mentoring: A Novel Approach to Facilitate Medical Student Applications to General Surgery Residency

OBJECTIVE

The COVID-19 pandemic rapidly altered the landscape of medical education, particularly disrupting the residency application process and highlighting the need for structured mentorship programs. This prompted our institution to develop a virtual mentoring program to provide tailored, one-on-one mentoring to medical students applying to general surgery residency. The aim of this study was to examine general surgery applicant perception of a pilot virtual mentoring curriculum.

DESIGN

The mentorship program included student-tailored mentoring and advising in 5 domains: resume editing, personal statement composition, requesting letters of recommendation, interview skills, and residency program ranking. Electronic surveys were administered following ERAS application submission to participating applicants. The surveys were distributed and collected via a REDCap database.

RESULTS

Eighteen out of 19 participants completed the survey. Confidence in a competitive resume (p = 0.006), interview skills (p < 0.001), obtaining letters of recommendation (p = 0.002), personal statement drafting (p < 0.001), and ranking residency programs (p < 0.001) were all significantly improved following completion of the program. Overall utility of the curriculum and likelihood to participate again and recommend the program to others was rated a median 5/5 on the Likert scale (5 [IQR 4-5]). Confidence in the matching carried a premedian 66.5 (50-65) and a postmedian 84 (75-91) (p = 0.004).

CONCLUSION

Following the completion of the virtual mentoring program, participants were found to be more confident in all 5 targeted domains. In addition, they were more confident in their overall ability to match. General Surgery applicants find tailored virtual mentoring programs to be a useful tool allowing for continued program development and expansion.

Isolated aortic arch anomalies are associated with defect severity and outcome in patients with congenital diaphragmatic hernia

PURPOSE

Congenital diaphragmatic hernia (CDH) patients often have suspected isolated aortic arch anomalies (IAAA) on imaging. The purpose of this work was to describe the incidence and outcomes of CDH + IAAA patients.

METHODS

Cardiovascular data were collected for infants from the CDH Study Group born between 2007 and 2019. IAAA were defined as coarctation of aorta, hypoplastic aortic arch, interrupted aortic arch, and aortic aneurysmal disease on early, postnatal echocardiography. Patients with major cardiac malformations and/or chromosomal abnormalities were excluded. Primary outcomes included the rate of aortic intervention, rates of extracorporeal life support (ECLS) utilization, and mortality.

RESULTS

Of 6357 CDH infants, 432 (7%) were diagnosed with a thoracic aortic anomaly. Of these, 165 were diagnosed with IAAA, most commonly coarctation of the aorta (n = 106; 64%) or hypoplastic aortic arch (n = 58; 35%). CDH + IAAA patients had lower birthweights (3 kg vs. 2.9 kg) and Apgar scores (7 vs. 6) than patients without IAAA (both χ² p < 0.001). CDH + IAAA were less likely to undergo diaphragm repair (72 vs. 87%, p < 0.001), and overall mortality was higher for CDH + IAAA infants (58 vs. 24%, p < 0.001). When controlling for defect size, birth weight, and Apgar, IAAA were significantly associated with mortality (OR 3.3, 95% CI 2.2-5.0; p < 0.01) but not associated with ECLS (OR 0.98, 95% CI 0.65-1.50; p = 0.90). Only 17% (n = 28) of CDH + IAAA patients underwent aortic intervention.

CONCLUSIONS

IAAA in CDH are associated with increased mortality. This often simply reflects severity of the defect and thoracic anatomic derangement, as opposed to unique aortic pathology, given few CDH + IAAA patients undergo aortic intervention.

Association of timing of congenital diaphragmatic hernia repair with survival and morbidity for patients not requiring extra-corporeal life support

BACKGROUND

While physiologic stabilization followed by repair has become the accepted paradigm for management of congenital diaphragmatic hernia (CDH), few studies have examined the effect of incremental changes in operative timing on patient outcomes. We hypothesized that later repair would be associated with higher morbidity and mortality.

METHODS

Data were queried from the CDH Study Group (CDHSG) from 2007-2020. Patients with chromosomal or cardiac abnormalities and those who were never repaired or required pre-repair extra-corporeal life support (ECLS) were excluded. Time to repair was analyzed both as a continuous variable and by splitting the cohort into top/bottom percentiles. The primary outcome of interest was in-hospital mortality. Secondary outcomes included need for and duration of post-repair ventilatory and nutritional support.

RESULTS

A total of 4,104 CDH infants were included. Median time to repair was 4 days (IQR 2-6). On multivariable analysis, high-risk (CDHSG stage C/D) defects and lower birthweight predicted later repair. Overall, in-hospital mortality was 6%. On univariate analysis, there was no difference in the number of days to repair between survivors and non-survivors. On risk-adjusted analysis, single-day changes in day of repair were not associated with increased mortality. Later repair was associated with longer time to reach full oral feeds, increased post-repair ventilator days, and increased need for tube feeds and supplementary oxygen at discharge.

CONCLUSIONS

For infants with isolated CDH not requiring pre-operative ECLS, there is no difference in mortality based on timing of repair, but single-day delays in repair are associated with increased post-repair duration of ventilatory and nutritional support.

Evaluation of Murine Host Sex as a Biological Variable in Transplanted Human Intestinal Organoid Development

BACKGROUND

Human intestinal organoids (HIOs), when transplanted into immunocompromised mice (tHIOs), demonstrate significant growth and maturation. While both male and female mice are reported to be viable hosts for these experiments, a direct comparison of sex-related differences in tHIO structure and development has not been performed.

AIMS

We sought to identify host sex-related differences in tHIO engraftment, morphology, and epithelial and mesenchymal development.

METHODS

HIOs were generated in vitro and transplanted beneath the kidney capsule of NSG male and female mice. tHIOs were harvested at 8-9 weeks. Anthropometric measurements were captured. tHIOs were divided in half and histology or RT-qPCR performed. Morphology was evaluated and epithelial architecture graded on a scale of 1 (absence of crypts/villi) to 4 (elongated crypt-villus axis). RT-qPCR and immunofluorescence microscopy were performed for epithelial and mesenchymal differentiation markers.

RESULTS

Host survival and tHIO engraftment were equivalent in male and female hosts. tHIO weight and length were also equivalent between groups. The number of lumens per tHIOs from male and female hosts was similar, but the mean lumen circumference was larger for tHIOs from male hosts. tHIOs from male hosts were more likely to demonstrate higher grades of epithelial development. However, both groups showed similar differentiation into secretory and absorptive epithelial lineages. Markers for intestinal identity, mesenchymal development, and brush border enzymes were also expressed similarly between groups.

CONCLUSIONS

While male host sex was associated with larger tHIO lumen size and mucosal maturation, tHIOs from both groups had similar engraftment, growth, and epithelial and mesenchymal cytodifferentiation.

Utilization of trauma nurse screening procedure for triage of the injured patient

PURPOSE

The treatment of trauma patients requires significant hospital resources. Numerous protocols exist to triage the injured patient and determine the level of care they may require. The purpose of this work is to describe an institutional trauma nurse screening procedure and to evaluate its effectiveness in triaging injured patients.

METHODS

This retrospective study was conducted at a large, tertiary trauma center from January to June 2021. Patients were assessed by trauma nurse clinicians (TNC) utilizing a standardized screening process to determine suitability for trauma activation. If the patient did not meet activation criteria, they were sent to the main Emergency Department for evaluation and treatment. Patients could be activated later by the emergency physician. The primary variables of interest were number of activations after initial "rule out," injury severity score (ISS) for patients who were activated, mechanism of injury, and disposition.

RESULTS

A total of 1874 TNC screenings were performed. Of these, 1449 (77%) patients did not meet trauma activation criteria. Only 41 (2.8%) patients initially ruled out were later activated by the emergency physician and admitted for treatment of injuries. The average ISS of all activated patients was 9 ± 6. Thirty-six patients had an ISS ≤ 15, four between 16 and 25, and only one patient had an ISS > 25. Twenty-seven patients were admitted to the ward, five went to step-down units, and five required intensive care unit admission. Four patients required operative intervention for their injuries.

CONCLUSION

These results suggest that nursing screening protocols can be safe, effective tools for triage of trauma patients.

Standardization of Pediatric Noncardiac Operating Room to Intensive Care Unit Handoffs Improves Communication and Patient Care

OBJECTIVES

Handoffs are critical points in transitioning care between multidisciplinary teams, yet data regarding intensive care unit (ICU) handoffs in pediatric noncardiac surgical patients are lacking. We hypothesized that standardized handoffs from the pediatric operating room (OR) to the ICU would improve physician presence, communication, and patient care parameters.

METHODS

This quality improvement initiative was performed at a tertiary children's hospital. Stakeholders (anesthesiologists, nurses, intensivists, and surgeons) developed a standardized OR to pediatric and neonatal ICU handoff process based on common goals and outcomes of interest. Baseline data were collected before intervention. Implementation was carried out in 2 phases, phase 1 with a written handoff and Phase 2 with a scripted handoff process. Data collected by trained observers included handoff attendance, distractions, and transfer of essential patient information. As a surrogate for outcomes, patient care parameter data were collected for 6 hours after transfer.

RESULTS

After phase 1, surgery and ICU physician attendance increased significantly, distractions decreased, and communication of essential patient data improved. In phase 2 (scripted handoff), attendance continued to rise, distractions remained decreased, and transfer of essential information was still improved compared with baseline. Mean handoff duration did not significantly change throughout the study. Certain patient care parameters (escalation of respiratory support, additional laboratory studies, vasopressor administration, antibiotic administration and timing) remained unchanged compared with baseline. However, the need for resuscitative fluid bolus or blood products significantly decreased after implementation phase 2.

CONCLUSIONS

Standardized handoffs for pediatric noncardiac surgical patients from the OR to the ICU can improve provider attendance and communication.

Neonatal rodent ventilation and clinical correlation in congenital diaphragmatic hernia

INTRODUCTION

Ventilator management is a critical part of managing congenital diaphragmatic hernia (CDH). We aimed to use a murine model and patient data to study CDH-associated differences in oxygenation, airway resistance, and pulmonary mechanics by disease severity.

METHODS

We used the nitrofen model of CDH. For control and CDH rodents, data were collected within the first hour of life. Oxygen saturations (SpO₂ ) were collected using MouseOx, and large airway resistance and inspiratory capacities were collected using flexiVent. A single-center, retrospective review of term CDH infants from 2014 to 2020 was performed. Tidal volumes were collected every 6 h for the first 48 h of life or until the patient was taken off conventional ventilation. Newborns that were mechanically ventilated but had no pulmonary pathology were used as controls. CDH severity was defined using the CDH Study Group (CDHSG) classification system.

RESULTS

Control rodents had a median SpO₂ of 94% (IQR: 88%-98%); CDH pups had a median SpO₂ of 27.9% (IQR: 22%-30%) (p < 0.01). CDH rodents had lower inspiratory capacity than controls (median: 110 μl, IQR: 70-170 vs. median: 267 μl, IQR: 216-352; p < 0.01). CDH infants had a lower initial SpO₂ than control infants. Overall, CDH infants had lower tidal volumes than control infants (median: 4.2 ml/kg, IQR: 3.3-5.0 vs. 5.4 ml/kg, IQR: 4.7-6.2; p = 0.03). Tidal volumes varied by CDHSG stage.

CONCLUSION

Newborns with CDH have lower SpO₂ and lower, CDHSG stage specific, tidal volumes than control infants. The nitrofen model of CDH reflects these differences. Rodent models may be useful in studying therapeutic ventilatory strategies for CDH infants.

How We Did It: Implementing a Trainee-Focused Surgical Research Curriculum and Infrastructure

OBJECTIVE

To describe the implementation of a department-wide research curriculum and infrastructure created to promote academic collaboration and productivity, particularly amongst trainees and junior investigators involved in basic, translational, clinical, quality, or education research.

DESIGN

Description of UT Southwestern Medical Center's (UTSW) surgical research resources and infrastructure and the development of a didactic curriculum focused on research methods, writing skills, and optimizing academic time and effort.

SETTING

The collaboration was initiated by UTSW Department of Surgery residents who were on dedicated research time (DRT) and grew to include trainees and faculty at all levels of the institution. Guest lecturers from institutions around the country were incorporated via virtual meeting platforms.

PARTICIPANTS

Medical students, residents, and clinical and research faculty from the Department of Surgery were invited to attend research meetings, didactics, and the guest-lecture series. Additionally, all groups were given access to shared resources and encouraged to share their own work.

RESULTS

A robust set of resources including data analysis tools, manuscript and grant writing templates, funding opportunities, and a comprehensive list of surgical conferences was created and made accessible to UTSW Surgery team members. Moreover, a curriculum of lectures covering a broad variety of topics for all types of research was created and has thus far reached an audience of over 40 UTSW Surgery trainees and staff.

CONCLUSIONS

A comprehensive set of lectures and resources targeted toward facilitating surgical research was designed and implemented at one of the largest surgical training programs in the country. This effort represents a low-cost, feasible, and accessible way to improve academic productivity and enhance the training of surgeon-scientists and can serve as a blueprint for other institutions around the country.

Telemedicine as a component of forward triage in a pandemic

Objective(s)

Coronavirus disease 2019 (COVID-19) presents an enormous challenge to healthcare systems globally. Optimizing access to healthcare while minimizing face-to-face patient encounters is critical to limiting exposures, conserving resources, and preserving health. We aimed to evaluate the utility of a COVID-focused telehealth program in avoiding potential in-person visits while maintaining high patient satisfaction.

Methods

All patients with COVID-related virtual visits at our center between March and May 2020 were included. Demographic, satisfaction, and clinical information were gathered using a modified, validated telehealth satisfaction questionnaire disseminated via email or telephone. Data were analyzed using Stata.

Results

Of 581 eligible patients, 180 (31%) responded to the survey. Symptoms (73%) and possible exposure (22%) were the main reasons cited for pursuing a virtual visit; cough (44%) and fever (36%) were the most common presenting symptoms. Regarding patient satisfaction, most patients rated the experience as “very good” or “excellent”, and 94% of respondents said they would recommend COVID-focused triage through telehealth to others. Over 81% of patients indicated that, if telehealth was not an option, they would have sought an in-person encounter. Ultimately, only 27% of patients reported pursuing a face-to-face encounter after participating in the virtual visit.

Conclusion

Based on patient self-reporting, telemedicine potentially prevented face-to-face COVID-related encounters. Patients expressed satisfaction with the virtual process and were less likely to pursue in-person consultation. Leveraging a telehealth strategy for forward triage has the potential to reduce exposures while conserving healthcare resources.

Incidence and outcomes of patients with congenital diaphragmatic hernia and pulmonary sequestration

BACKGROUND

Bronchopulmonary sequestration (BPS) has long been identified in patients with congenital diaphragmatic hernia (CDH), however the reported incidence in the literature varies widely and is not based on large series.

METHODS

Version 4 of the Congenital Diaphragmatic Hernia Study Group (CDHSG) included questions specifically identifying BPS-associated cases. The data were prospectively collected between 2015 and 2020. Clinical characteristics and outcomes for CDH+BPS patients were compared to patients without BPS using univariate and multiple regression analyses.

RESULTS

Out of 2118 total patients, 72 had a pulmonary sequestration (3.4%). The amount of CDH+BPS with high-risk (CDHSG type C and D) defects was significantly greater than those without BPS (68.0% vs 49.3%, respectively; p = 0.001). The need for ECLS (35/72, 48.6%) and overall mortality (21/72, 29.2%) was significantly higher in CDH+BPS. When corrected for hernia size, cardiac and chromosomal anomalies, the need for ECLS (OR 2.2, p = 0.004) and mortality (OR 2.0, p = 0.015) was significantly greater in CDH+BPS.

CONCLUSIONS

This is the largest series to look at the incidence of BPS in children with CDH. They are associated with larger defect sizes, a greater need for ECLS and higher mortality than those patients without BPS.

Elevated proBNP levels are associated with disease severity, cardiac dysfunction, and mortality in congenital diaphragmatic hernia

BACKGROUND

Cardiac dysfunction is a key determinant of outcome in congenital diaphragmatic hernia (CDH). Pro-b-type natriuretic peptide (proBNP) is used as a prognosticator in heart failure and cardiomyopathy. We hypothesized that proBNP levels would be associated with ventricular dysfunction and high-risk disease in CDH.

METHODS

Patients in the CDH Study Group (CDHSG) from 2015-2019 with at least one proBNP value were included. Ventricular function was determined using echocardiograms from the first 48 h of life.

RESULTS

A total of 2,337 patients were identified, and 212 (9%) had at least one proBNP value. Of those, 3 (1.5%) patients had CDHSG stage A defects, 58 (29.6%) B, 111 (56.6%) C, and 24 (12.2%) D. Patients with high-risk defects (Stage C/D) had higher proBNP compared with low-risk defects (Stage A/B) (14,281 vs. 5,025, p = 0.007). ProBNP was significantly elevated in patients who died (median 14,100, IQR 4,377-22,900 vs 4,911, IQR 1,883-9,810) (p<0.001). Ventricular dysfunction was associated with higher proBNP than normal ventricular function (8,379 vs. 4,778, p = 0.005). No proBNP value was both sensitive and specific for ventricular dysfunction (AUC=0.61).

CONCLUSION

Among CDH patients, elevated proBNP was associated with high-risk defects, ventricular dysfunction, and mortality. ProBNP shows promise as a biomarker in CDH-associated cardiac dysfunction.

Birth weight predicts patient outcomes in infants who undergo congenital diaphragmatic hernia repair

PURPOSE

The purpose of this study was to analyze the clinical characteristics and outcomes of low birthweight (LBW) infants with congenital diaphragmatic hernia (CDH) compared to normal birthweight (NBW) infants with CDH. We hypothesized that LBW was associated with increased mortality, decreased extracorporeal life support (ECLS) utilization, and increased pulmonary morbidity in CDH patients.

METHODS

Patients in the CDH Study Group from 2007 to 2018 were included. LBW was defined as <2.5 kg. Clinical characteristics and outcomes for LBW patients were compared to normal birthweight (NBW) patients using univariate and multivariable analyses.

RESULTS

Of 5,586 patients, 1,157 (21%) were LBW. LBW infants had more congenital anomalies and larger diaphragmatic defects than NBW infants. ECLS utilization was decreased, and overall mortality was increased among LBW infants compared to NBW infants. A 1 kg increase in birthweight was associated with 34% higher odds of survival after repair (adjusted Odds Ratio 1.34, 95% CI 1.03-1.76; p = .03). LBW infants had longer durations of mechanical ventilation and were more likely to require supplemental oxygen at 30 days and at the time of discharge.

CONCLUSION

LBW is a risk factor for mortality and pulmonary morbidity in CDH. Prolonged oxygen requirement and increased length of stay are important considerations when managing this population.

Injury Severity, Arrival Physiology, Coagulopathy, and Outcomes Among the Youngest Trauma Patients

BACKGROUND

Although physiologic differences exist between younger and older children, pediatric trauma analyses are weighted toward older patients. Trauma-induced coagulopathy, determined by rapid thrombelastography (rTEG), is a predictor of outcome in trauma patients, but the significance of rTEG values among very young trauma patients remains unknown. Our objective was to identify the prehospital or physiologic factors, including rTEG values, that were associated with mortality in trauma patients younger than 5 y old.

MATERIALS AND METHODS

Patients younger than 5 y old that met the highest-level trauma activation criteria at an academic children's hospital from 2010-2016 were included. Data regarding demographics, pre-hospital management, laboratory values, injury severity, and outcome were queried. Univariate and multivariate analyses were performed comparing survivors and non-survivors.

RESULTS

A total of 356 patients were included. 60% were male, and the median age was 3 y (IQR 1-4). Overall mortality was 13% (n = 45); brain injury (91%) and hemorrhage (9%) were the causes of death. Compared to survivors, rTEG values in nonsurvivors showed longer activated clotting time and slower speed of clot formation. Clot strength was also decreased in nonsurvivors. On stepwise regression modeling, rTEG values were not significant predictors of mortality. Admission base deficit, arrival temperature, and head injury severity were identified as independent predictors of mortality.

CONCLUSIONS

While rTEG identified coagulopathy in trauma patients < 5 y old, it was not an independent predictor of mortality. Our findings suggest that trauma providers should pay close attention to admission base deficit, arrival temperature, and head injury severity when managing the youngest trauma patients.

Early, Postnatal Pulmonary Hypertension Severity Predicts Inpatient Outcomes in Congenital Diaphragmatic Hernia

INTRODUCTION

Pulmonary hypertension (PH) is the major pathophysiologic consequence of congenital diaphragmatic hernia (CDH). We aimed to evaluate the association between early CDH-associated PH (CDH-PH) and inpatient outcomes.

METHODS

The CDH Study Group registry was queried for infants born 2015-2019 with echocardiograms before 48h of life. PH was categorized using echocardiographic findings: none, mild (right ventricular systolic pressure <2/3 systemic), moderate (between 2/3 systemic and systemic), or severe (supra-systemic). Univariate and multivariate analyses were performed. Adjusted Poisson regression was used to assess the primary composite outcome of mortality or oxygen support at 30 days.

RESULTS

Of 1,472 patients, 86.5% had CDH-PH: 13.9% mild (n = 193), 44.4% moderate (n = 631), and 33.2% severe (n = 468). On adjusted analysis, the primary outcome of mortality or oxygen support at 30 days occurred more frequently in infants with moderate (incidence rate ratio [IRR] 1.8, 95% confidence interval [CI], 1.2-2.6) and severe CDH-PH (IRR 2.0, 95% CI, 1.3-2.9). Extracorporeal life support (ECLS) utilization was associated only with severe CDH-PH after adjustment (IRR 1.8, 95% CI, 1.0-3.3).

DISCUSSION/CONCLUSION

Early, postnatal CDH-PH is independently associated with increased risk for mortality or oxygen support at 30 days and utilization of ECLS. Early echocardiogram is a valuable prognostic tool for early, inpatient outcomes in neonates with CDH.

Extracellular vesicles influence the pulmonary arterial extracellular matrix in congenital diaphragmatic hernia

OBJECTIVE

Abnormal pulmonary vasculature directly affects the development and progression of congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension (PH). Though overarching structural and cellular changes in CDH-affected pulmonary arteries have been documented, the precise role of the extracellular matrix (ECM) in the pulmonary artery (PA) pathophysiology remains undefined. Here, we quantify the structural, compositional, and mechanical CDH-induced changes in the main and distal PA ECM and investigate the efficacy of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) as a therapy to ameliorate pathological vascular ECM changes.

METHODS

Pregnant Sprague-Dawley rodents were administered nitrofen to induce CDH-affected pulmonary vasculature in the offspring. A portion of CDH-affected pups was treated with intravenous infusion of MSC-EVs (1 × 10¹⁰ /mL) upon birth. A suite of histological, mechanical, and transmission electron microscopic analyses were utilized to characterize the PA ECM.

RESULTS

The CDH model main PA presented significantly altered characteristics-including greater vessel thickness, greater lysyl oxidase (LOX) expression, and a relatively lower ultimate tensile strength of 13.6 MPa compared to control tissue (25.1 MPa), suggesting that CDH incurs ECM structural disorganization. MSC-EV treatment demonstrated the potential to reverse CDH-related changes, particularly through rapid inhibition of ECM remodeling enzymes (LOX and MMP-9). Additionally, MSC-EV treatment bolstered structural aspects of the PA ECM and mitigated pathological disorganization as exhibited by increased medial wall thickness and stiffness that, while not significantly altered, trends away from CDH-affected tissue.

CONCLUSIONS

These data demonstrate notable ECM remodeling in the CDH pulmonary vasculature, along with the capacity of MSC-EVs to attenuate pathological ECM remodeling, identifying MSC-EVs as a potentially efficacious therapeutic for CDH-associated pulmonary hypertension.

Extracellular Vesicles Attenuate Nitrofen-Mediated Human Pulmonary Artery Endothelial Dysfunction: Implications for Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) leads to pathophysiologic pulmonary vasoreactivity. Previous studies show that mesenchymal stromal cell-derived extracellular vesicles (MSCEv) inhibit lung inflammation and vascular remodeling. We characterize MSCEv and human pulmonary artery endothelial cell (HPAEC) interaction, as well as the pulmonary artery (PA) response to MSCEv treatment. HPAECs were cultured with and without exposure to nitrofen (2,4-dichloro-phenyl-p-nitrophenylether) and treated with MSCEv. HPAEC viability, architecture, production of reactive oxygen species (ROS), endothelial dysfunction-associated protein levels (PPARγ, LOX-1, LOX-2, nuclear factor-κB [NF-κB], endothelial NO synthase [eNOS], ET-1 [endothelin 1]), and the nature of MSCEv-cellular interaction were assessed. Newborn rodents with and without CDH (nitrofen model and Sprague-Dawley) were treated with intravascular MSCEv or vehicle control, and their PAs were isolated. Contractility was assessed by wire myography. The contractile (KCL and ET-1) and relaxation (fasudil) responses were evaluated. HPAEC viability correlated inversely with nitrofen dose, while architectural compromise was directly proportional. There was a 2.1 × increase in ROS levels in nitrofen HPAECs (P < 0.001), and MSCEv treatment attenuated ROS levels by 1.5 × versus nitrofen HPAECs (P < 0.01). Nitrofen-induced alterations in endothelial dysfunction-associated proteins are shown, and exposure to MSCEv restored more physiologic expression. Nitrofen HPAEC displayed greater MSCEv uptake (80% increase, P < 0.05). Adenosine, a clathrin-mediated endocytosis inhibitor, decreased uptake by 46% (P < 0.05). CDH PA contraction was impaired with KCL (108.6% ± 1.4% vs. 112.0% ± 1.4%, P = 0.092) and ET-1 (121.7% ± 3.0% vs. 131.2% ± 1.8%, P < 0.01). CDH PA relaxation was impaired with fasudil (32.2% ± 1.9% vs. 42.1% ± 2.2%, P < 0.001). After MSCEv treatment, CDH PA contraction improved (125.9% ± 3.4% vs. 116.4 ± 3.5, P = 0.06), and relaxation was unchanged (32.5% ± 3.2% vs. 29.4% ± 3.1%, P = 0.496). HPAEC exposure to nitrofen led to changes consistent with vasculopathy in CDH, and MSCEv treatment led to a more physiologic cellular response. MSCEv were preferentially taken up by nitrofen-treated cells by clathrin-dependent endocytosis. In vivo, MSCEv exposure improved PA contractile response. These data reveal mechanisms of cellular and signaling alterations that characterize MSCEv-mediated attenuation of pulmonary vascular dysfunction in CDH-associated pulmonary hypertension.

Congenital diaphragmatic hernia-associated pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is a neonatal pathology in which intrathoracic herniation of abdominal viscera via diaphragmatic defect results in aberrant pulmonary and cardiovascular development. Despite decades of study and many advances in the diagnosis and treatment of CDH, morbidity and mortality remain high, largely due to pulmonary hypertension (PH), along with pulmonary hypoplasia and cardiac dysfunction. In patients with CDH, hypoplastic pulmonary vasculature and alterations in multiple molecular pathways lead to pathophysiologic pulmonary vasculopathy and, for severe CDH, sustained, elevated pulmonary arterial pressures. This review addresses the multiple anatomic and physiologic changes that underlie CDH-associated PH (CDH-PH), along with the multimodal treatment strategies that exist currently and future therapies currently under investigation.

A randomized controlled prospective study to assess the role of subconjunctival bevacizumab in primary pterygium surgery in Indian patients

BACKGROUND

Pterygium is an ocular surface disorder with prevalence rates ranges from 0.3% to 29% in different parts of the world. Vascular endothelial growth factor (VEGF) has been detected in increased amounts in pterygium epithelium, compared with normal conjunctiva. Bevacizumab is a recombinant, humanized anti-VEGF antibody suggested as a possible adjunctive therapy for pterygium excision that appears to have a role in prevention of recurrence. We conducted this study to evaluate the role of subconjunctival bevacizumab in primary pterygium surgery in Indian patients.

METHODS

In this randomized prospective clinical study, the patients were randomized into two groups of 30 patients each. Study group received 1.25 mg/0.05 ml subconjunctival bevacizumab 1 week before pterygium surgery with conjunctival autograft. Control group received 1.25 mg (0.05 ml) subconjunctival normal saline 1 week prior to pterygium surgery with conjunctival autograft. Patients were followed up at day 1, day 7, 1 month and 3 months. The main outcome measures were morphology of pterygium after injection, intra-operative ease, recurrence of pterygia, and any complications.

RESULTS

After giving bevacizumab, there was statistically significant improvement in grade, color intensity, size of pterygium, and symptoms of patients. Intra-operatively, less bleeding was observed by the surgeon. No statistically significant difference regarding reduction in astigmatism, improvement of visual acuity, and complications were observed in two groups. Recurrence was noted in five patients (8.33%) in total study population at the end of 3 months. It was present in two patients (6.67%) in Group A and three patients (10%) in Group B.

CONCLUSION

Single preoperative administration of subconjunctival injection bevacizumab given 1 week before the pterygium excision with conjunctival autograft decreases the vascularity of newly formed blood vessels, hence may decrease recurrence rate though not in our study.

Way toward "dietary pesticides": molecular investigation of insecticidal action of caffeic acid against Helicoverpa armigera

Bioprospecting of natural molecules is essential to overcome serious environmental issues and pesticide resistance in insects. Here we are reporting insights into insecticidal activity of a plant natural phenol. In silico and in vitro screening of multiple molecules supported by in vivo validations suggested that caffeic acid (CA) is a potent inhibitor of Helicoverpa armigera gut proteases. Protease activity and gene expression were altered in CA-fed larvae. The structure-activity relationship of CA highlighted that all the functional groups are crucial for inhibition of protease activity. Biophysical studies and molecular dynamic simulations revealed that sequential binding of multiple CA molecules induces conformational changes in the protease(s) and thus lead to a significant decline in their activity. CA treatment significantly inhibits the insect's detoxification enzymes, thus intensifying the insecticidal effect. Our findings suggest that CA can be implicated as a potent insecticidal molecule and explored for the development of effective dietary pesticides.

Differential protease activity augments polyphagy in Helicoverpa armigera

Helicoverpa armigera (Lepidoptera: Noctuidae) and other polyphagous agricultural pests are extending their plant host range and emerging as serious agents in restraining crop productivity. Dynamic regulation, coupled with a diversity of digestive and detoxifying enzymes, play a crucial role in the adaptation of polyphagous insects. To investigate the functional intricacy of serine proteases in the development and polyphagy of H. armigera, we profiled the expression of eight trypsin-like and four chymotrypsin-like phylogenetically diverse mRNAs from different life stages of H. armigera reared on nutritionally distinct host plants. These analyses revealed diet- and stage-specific protease expression patterns. The trypsins expressed showed structural variations, which might result in differential substrate specificity and interaction with inhibitors. Protease profiles in the presence of inhibitors and their mass spectrometric analyses revealed insight into their differential activity. These findings emphasize the differential expression of serine proteases and their consequences for digestive physiology in promoting polyphagy in H. armigera.

Chemical stability of brompheniramine maleate in an oral liquid dosage form

The chemical stability of brompheniramine maleate in an oral liquid dosage form was studied by using a stability-indicating high-performance liquid chromatographic assay method that was developed in the University of Houston (Houston, Texas) laboratory. The concentrations of the drug were directly related to peak heights, with an R value of 0.999. The percent relative standard deviation based on five injections was 1.0. The formulation was stable for at least 202 days when stored in amber-colored glass bottles at room temperature. The pH value of the formulation remained constant at 2.7 after 202 days of storage, and the physical appearance of the formulation did not change.

Mitochondrial haplotypes reveal a strong genetic structure for three Indian sheep breeds

This survey represents the first characterization of mitochondrial DNA diversity within three breeds of Indian sheep (two strains of the Deccani breed, as well as the Bannur and Garole breeds) from different geographic regions and with divergent phenotypic characteristics. A 1061-bp fragment of the mitochondrial genome spanning the control region, a portion of the 12S rRNA gene and the complete phenyl tRNA gene, was sequenced from 73 animals and compared with the corresponding published sequence from European and Asian breeds and the European Mouflon (Ovis musimon). Analysis of all 156 sequences revealed 73 haplotypes, 52 of which belonged to the Indian breeds. The three Indian breeds had no haplotypes in common, but one Indian haplotype was shared with European and other Asian breeds. The highest nucleotide and haplotype diversity was observed in the Bannur breed (0.00355 and 0.981 respectively), while the minimum was in the Sangamneri strain of the Deccani breed (0.00167 and 0.882 respectively). All 52 Indian haplotypes belonged to mitochondrial lineage A. Therefore, these Indian sheep are distinct from other Asian and European breeds studied so far. The relationships among the haplotypes showed strong breed structure and almost no introgression among these Indian breeds, consistent with Indian sheep husbandry, which discourages genetic exchange between breeds. These results have implications for the conservation of India's ovine biodiversity and suggest a common origin for the breeds investigated.

Development of an integrated intraspecific map of chickpea (Cicer arietinum L.) using two recombinant inbred line populations

A composite intraspecific linkage map of chickpea was developed by integrating individual maps developed from two F(8:9) RIL populations with one common parent. Different molecular markers viz. RAPD, ISSR, RGA, SSR and ASAP were analyzed along with three yield related traits: double podding, seeds per pod and seed weight. A total of 273 markers and 186 RILs were used to generate the map with eight linkage groups at a LOD score of >/=3.0 and maximum recombination fraction of 0.4. The map spanned 739.6 cM with 230 markers at an average distance of 3.2 cM between markers. The predominantly used SSR markers facilitated identification of homologous linkage groups from the previously published interspecific linkage map of chickpea and confirmed conservation of the SSR markers across the two maps as well as the variation in terms of marker distance and order. The double podding gene was tagged by the markers NCPGR33 and UBC249z at 2.0 and 1.1 cM, respectively. Whereas, seeds per pod, was tagged by the markers TA2x and UBC465 at 0.1 and 1.8 cM, respectively. Eight QTLs were identified that influence seed weight. The joint map approach allowed mapping a large number of markers with a moderate coverage of the chickpea genome and few linkage gaps.

Molecular mapping of stem and leaf rust resistance in wheat

Stem rust caused by Puccinia graminis f. sp. tritici Eriks and Henn and leaf rust caused by Puccinia triticina Rob. ex Desm. are major constraints to wheat production worldwide. In the present study, F(4)-derived SSD population, developed from a cross between Australian cultivars 'Schomburgk' and 'Yarralinka', was used to identify molecular markers linked to rust resistance genes Lr 3 a and Sr 22. A total of 1,330 RAPD and 100 ISSR primers and 33 SSR primer pairs selected ob the basis of chromosomal locations of these genes were used. The ISSR marker UBC 840(540) was found to be linked with Lr 3 a in repulsion at a distance of 6.0 cM. Markers cfa 2019 and cfa 2123 flanked Sr 22 at a distance of 5.9 cM (distal) and 6.0 cM (proximal), respectively. The use of these markers in combination would predict the presence or absence of Sr 22 in breeding populations. A previously identified PCR-based diagnostic marker STS 638 linked to Lr 20 was validated in this population. This marker showed a recombination value of 7.1 cM with Lr 20.

Pattern of intraocular pressure in epidemic dropsy in India

This study was conducted to report on the intraocular pressure (IOP) pattern in patients with epidemic dropsy. Two hundred and thirty proven cases of epidemic dropsy were sent for ocular examination. We measured IOP by applanation tonometry at different intervals. Patients were followed up until 24 weeks. Intraocular pressure of more than 22 mm of Hg was detected in 10.86% patients at the start of the study. However, at 12 weeks only 0.43% patients needed medication for control of IOP. None required medication for IOP control after 20 weeks. The rise of IOP in this case series of epidemic dropsy appeared to be a transient phenomenon and drugs needed to be titrated on a weekly basis.

Detection of Genetic Variability in Pearl Millet Downy Mildew (Sclerospora graminicola) by AFLP

Downy mildew, caused by Sclerospora graminicola, is an economically important disease of pearl millet in the semiarid regions of Asia and Africa. Amplified restriction fragment length polymorphism (AFLP) was used to detect the extent of genomic variation among 19 fungal isolates from different cultivars of pearl millet grown in various regions of India. Fourteen AFLP primer combinations produced 184 polymorphic bands. An unweighted pair-group method of averages cluster analysis represented by dendrogram and principal coordinate analysis separated the mildew collections into four distinct groups. Isolates having characteristic opposite mating abilities, geographic relatedness, virulence, common host cultivars, and changes through asexual generations reflected heterogeneity of the pathogen. The use of AFLP to detect genetic variation is particularly important in selecting mildew isolates to screen breeding material for identification of resistant millet and monitoring changes in S. graminicola in relation to changes in host for effective disease management.

Acute lymphocytic leukemia presenting as masquerade syndrome

An 11-year-old child presented with plastic iridocyclitis and hypopyon. Subsequent paracentesis revealed leukemic infiltrates. A bone marrow biopsy confirmed the diagnosis of acute lymphocytic leukemia. Because of this unusual case of leukemic hypopyon, we advocate anterior chamber paracentesis and pediatrician referral in all cases of refractory uveitis.

Molecular marker analysis of protein content using PCR-based markers in wheat

Grain protein concentration (GPC) of hexaploid wheat is one of the important factors that determines the end-product quality as well as playing a pivotal role in human nutrition. In an attempt to identify PCR-based DNA markers linked to GPC, 106 recombinant inbred lines (RILs) were developed from a cross between two wheat cultivars PH132 and WL711, which differ significantly in GPC, by the single seed descent method. The RILs were phenotyped for GPC at two diverse agroclimatic locations, namely Pune and Ludhiana, to study the influence of genotype and environment interactions on this trait. The parents were screened with 85 inter simple sequence repeat (ISSR) primers and 350 random primers. The selective genotyping and whole population analysis revealed nine DNA markers associated with the trait. Three markers (UBC8441100, UBC8801000, and OPA4800) were observed to be associated with the trait in both locations, whereas two markers (OPH41400) and UBC873750) werefound to be specific to Pune, and four markers (OPM5870, OPO10870, OPV141200, and UBC8251000) were specific to Ludhiana. Together five markers at the Pune location representing five QTLs and seven markers at Ludhiana representing four QTLs accounted for 13.4 and 13.5% of total phenotypic variation, respectively. This study clearly demonstrates that GPC is highly influenced by the environment, and the applicability of ISSR and RAPD markers in finding regions on chromosomes associated with quantitative characters in wheat such as GPC.

Genetic diversity across natural populations of three montane plant species from the Western Ghats, India revealed by intersimple sequence repeats

We analysed genetic diversity across the natural populations of three montane plant species in the Western Ghats, India; Symplocos laurina, Gaultheria fragrantissima and Eurya nitida using intersimple sequence repeat (ISSR) markers. These markers revealed genetic diversity within the populations of these plants from Nilgiri and also between two populations of S. laurina from Nilgiri and Amboli. Genetic variation within and between populations was analysed using various parameters such as total heterozygosity (HT), heterozygosity within population (HS), diversity between populations (DST), coefficient of population differentiation (GST), genetic distance (D) and gene flow (Nm). Total heterozygosity (HT) was higher for S. laurina (0.238) than for G. fragrantissima (0.172) and E. nitida (0.182). Two populations of S. laurina, separated by > 1000 km, showed a high within-population variation (53.7%) and a low gene flow (Nm = 0.447). upgma phenograms depicted a tendency of accessions to group according to their geographical locations in all the three plant species. The insight gained into the genetic structure of these plant populations might have implications in developing in situ and ex situ conservation strategies.

Comparative analysis of genetic diversity among Indian populations of Scirpophaga incertulas by ISSR-PCR and RAPD-PCR

Genetic variation between 28 Indian populations of the rice pest, Scirpophaga incertulas was evaluated using inter-simple sequence repeats (ISSR)-PCR assay. Nine SSR primers gave rise to 79 amplification products of which 67 were polymorphic. A dendrogram constructed from this data indicates that there is no geographical bias to the clustering and that gene flow between populations appears to be relatively unrestricted, substantiating our earlier conclusion based on the RAPD (random amplified polymorphic DNA) data. The dendrograms obtained using each of these marker systems were poorly correlated with each other as determined by Mantel's test for matrix correlation. Estimates of expected heterozygosity and marker index for each of these marker systems suggests that both these marker systems are equally efficient in determining polymorphisms. Matrix correlation analyses suggest that reliable estimates of genetic variation among the S. incertulas pest populations can be obtained by using RAPDs alone or in combination with ISSRs, but ISSRs alone cannot be used for this purpose.

Use of three different marker systems to estimate genetic diversity of Indian elite rice varieties

Genetic diversity among 42 Indian elite rice varieties, which is important for selection of parents for conventional breeding and hybrid program, was evaluated using three different types of DNA markers and parentage analysis. Random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR) and sequence tagged microsatellite site (STMS) markers resulted in mean heterozygosity values of 0.429, 0.675 and 0.882 over all loci, respectively, and marker index values of 2.21, 4.05 and 5.49, respectively. The three molecular marker systems together provide wider genome coverage and, therefore, would be a better indicator of the genetic relationships among the 42 elite rice cultivars than those revealed using individual molecular markers. A total of 153 bands (91%) were polymorphic out of 168 bands amplified, considering all the markers together. The average genetic similarity coefficient across all the 861 cultivar pairs was 0.70 while the average coefficient of parentage was 0.10. Cluster analysis revealed that there was a very poor correlation (correlation coefficient <0.1) between dendrograms generated using coefficients of parentage and molecular marker generated genetic similarities, which can be attributed to selection pressure, genetic drift, sampling of loci and unknown relationships among supposedly unrelated ancestors.

Marker assisted selection of bacterial blight resistance genes in rice

Bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae is one of the most important diseases affecting rice production in Asia. We were interested in surveying rice genotypes that are popularly used in the Indian breeding program for conferring resistance to bacterial blight, using 11 STMS and 6 STS markers. The basis of selection of these DNA markers was their close linkage to xa5, xa13, and Xa21 genes and their positions on the rice genetic map relative to bacterial blight resistance genes. Eight lines were found to contain the xa5 gene while two lines contained Xa21 gene and none of the lines contained the xa13 gene with the exception of its near-isogenic line. Using the polymorphic markers obtained in the initial survey, marker-assisted selection was performed in the F3 population of a cross between IR-64 and IET-14444 to detect lines containing multiple resistance genes. Of the 59 progeny lines analyzed, eight lines contained both the resistance genes, xa5 and Xa4.

Differential distribution of simple sequence repeats in eukaryotic genome sequences

Complete chromosome/genome sequences available from humans, Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana, and Saccharomyces cerevisiae were analyzed for the occurrence of mono-, di-, tri-, and tetranucleotide repeats. In all of the genomes studied, dinucleotide repeat stretches tended to be longer than other repeats. Additionally, tetranucleotide repeats in humans and trinucleotide repeats in Drosophila also seemed to be longer. Although the trends for different repeats are similar between different chromosomes within a genome, the density of repeats may vary between different chromosomes of the same species. The abundance or rarity of various di- and trinucleotide repeats in different genomes cannot be explained by nucleotide composition of a sequence or potential of repeated motifs to form alternative DNA structures. This suggests that in addition to nucleotide composition of repeat motifs, characteristic DNA replication/repair/recombination machinery might play an important role in the genesis of repeats. Moreover, analysis of complete genome coding DNA sequences of Drosophila, C. elegans, and yeast indicated that expansions of codon repeats corresponding to small hydrophilic amino acids are tolerated more, while strong selection pressures probably eliminate codon repeats encoding hydrophobic and basic amino acids. The locations and sequences of all of the repeat loci detected in genome sequences and coding DNA sequences are available at http://www.ncl-india.org/ssr and could be useful for further studies.

Use of DNA markers in prediction of hybrid performance and heterosis for a three-line hybrid system in rice

Two Cytoplasmic Male Sterile lines were crossed with fourteen restorer lines of rice widely grown in the western regions of Maharashtra, India, to produce 28 F1 hybrids which were evaluated for eight agronomically important traits, contributing to yield potential, in replicated field trials. The hybrid performance was recorded along with heterosis and heterobeltiosis. All the rice lines under investigation were subjected to marker-based variability analysis. An attempt was made to correlate genetic distance based on specific markers for each trait individually, as well as average genetic distance based on all specific markers, with hybrid performance and heterosis, by regression analysis. Specific markers could cluster the parental lines in different groups and showed significant correlation with hybrid performance. The data also supports the proposition that epistasis is the basis of heterosis. The analysis, however, revealed a lack of significant predictive values for field application.

Complexity in specificities and expression of Helicoverpa armigera gut proteinases explains polyphagous nature of the insect pest

Helicoverpa armigera is a devastating pest of cotton and other important crop plants all over the world. A detailed biochemical investigation of H. armigera gut proteinases is essential for planning effective proteinase inhibitor (PI)-based strategies to counter the insect infestation. In this study, we report the complexity of gut proteinase composition of H. armigera fed on four different host plants, viz. chickpea, pigeonpea, cotton and okra, and during larval development. H. armigera fed on chickpea showed more than 2.5- to 3-fold proteinase activity than those fed on the other host plants. H. armigera gut proteinase composition revealed the predominance of serine proteinase activity; however, the larvae fed on pigeonpea revealed the presence of metalloproteases and low levels of aspartic and cysteine proteases as well. Gut proteinase activity increased during larval development with the highest activity seen in the fifth instar larvae which, however, declined sharply in the sixth instar. Over 90% of the gut proteinase activity of the fifth instar larvae was of the serine proteinase type, however, the second instar larvae showed the presence of proteinases of other mechanistic classes like metalloproteases, aspartic and cysteine proteases along with serine proteinase activity as evident by inhibition studies. Analysis of fecal matter of larvae showed significant increase in proteinase activity when fed on an artificial diet with or without non-host PIs than larvae fed on a natural diet. The diversity in the proteinase activity observed in H. armigera gut and the flexibility in their expression during developmental stages and depending upon the diet provides a base for selection of proper PIs for insect resistance in transgenic crop plants.

Genetic variation in Indian populations of Scirpophaga incertulas as revealed by RAPD-PCR analysis

Scirpophaga incertulas, commonly referred to as yellow stem borer, is a predominant pest of rice causing serious losses in its yield. Genetic variation among populations of Scirpophaga incertulas collected from 28 hotspot locations in India was examined using the randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). In all, 32 primers were used and 354 amplification products were observed. No RAPD-PCR bands diagnostic to the pest population from any specific region were identified. Cluster analysis using UPGMA showed that, with the exception of the pest population from Pattambi, all the populations cluster as one group with GD values in the range of 6-22%, suggesting that gene flow between populations is independent of geographic distance and appears to be unrestricted. The relatively high GD value of 48% exhibited by the pest population from Pattambi was the only exception.

Ty1-copia retrotransposon-like elements in chickpea genome: their identification, distribution and use for diversity analysis

Ty1-copia retrotransposon-like elements were amplified from Cicer species using primers derived from the conserved region of the reverse transcriptase gene. Two fragments, of size approximately 280bp and approximately 650 bp, were obtained, which on sequencing showed homology for the Ty1-copia reverse transcriptase region. Interestingly, the approximately 650 bp fragment showed two reverse transcriptase regions, one from Ty1-copia and the other from Tto1 element fused together. The copy number was high in the cultivated Cicer arietinum genome compared with the wild Cicer reticulatum. Genetic diversity among the Cicer species was investigated using the conserved primers which grouped the wild species and the cultivated C. arietinum separately.

TRES: comparative promoter sequence analysis

Comparative promoter analysis is a promising strategy for elucidation of common regulatory modules conserved in evolutionarily related sequences or in genes showing common expression profiles. To facilitate such analysis, we have developed a software tool that detects conserved transcription factor binding sites, cis-elements, palindromes and k-tuples simultaneously in a set of sequences, and thus helps to identify putative motifs for designing further experiments.

Amino acid repeat patterns in protein sequences: their diversity and structural-functional implications

All the protein sequences from SWISS-PROT database were analyzed for occurrence of single amino acid repeats, tandem oligo-peptide repeats, and periodically conserved amino acids. Single amino acid repeats of glutamine, serine, glutamic acid, glycine, and alanine seem to be tolerated to a considerable extent in many proteins. Tandem oligo-peptide repeats of different types with varying levels of conservation were detected in several proteins and found to be conspicuous, particularly in structural and cell surface proteins. It appears that repeated sequence patterns may be a mechanism that provides regular arrays of spatial and functional groups, useful for structural packing or for one to one interactions with target molecules. To facilitate further explorations, a database of Tandem Repeats in Protein Sequences (TRIPS) has been developed and is available at URL: http://www.ncl-india.org/trips.

Pearl millet cysteine protease inhibitor. Evidence for the presence of two distinct sites responsible for anti-fungal and anti-feedent activities

Recently, pearl millet cysteine protease inhibitor (CPI) was, for the first time, shown to possess anti-fungal activity in addition to its anti-feedent (protease inhibitory) activity [Joshi, B.N. et al. (1998) Biochem. Biophys. Res. Commun. 246, 382-387]. Characterization of CPI revealed that it has a reversible mode of action for protease inhibition. The CD spectrum exhibited a 35% alpha helix and 65% random coil structure. The intrinsic fluorescence spectrum was typical of a protein devoid of tryptophan residues. Demetallation of Zn2+ resulted in a substantial change in the secondary and tertiary structure of CPI accompanied by the complete loss of anti-fungal and inhibitory activity indicating that Zn2+ plays an important role in maintaining both structural integrity and biological function. The differential response of anti-fungal and inhibitory activities to specific modifiers showed that there are two different reactive sites associated with anti-fungal and anti-feedent activity in CPI located on a single protein as revealed from its N-terminal sequence data (AGVCYGVLGNNLP). Modification of cysteine, glutamic/aspartic acid or argnine resulted in abolition of the anti-fungal activity of CPI, whereas modification of arginine led to an enhancement of the inhibitory activity in solution. Modification of histidine resulted in a twofold increase in the protease inhibitory activity without affecting the anti-fungal activity, whereas modification of serine led to selective inhibition of the protease inhibitory activity. The differential nature of the two activities was further supported by differences in the temperature stabilities of the anti-fungal (60 degrees C) and inhibitory (40 degrees C) activities. Binding of papain to CPI did not abolish the anti-fungal activity of CPI, supporting the presence of two active sites on CPI. The differential behavior of CPI towards anti-fungal and anti-feedent activity cannot be attributed to changes in conformation, as assessed by their CD and fluorescence spectra. The interaction of CPI modified for arginine or histidine with papain resulted in an enhancement of CPI activity accompanied by a slight decrease in fluorescence intensity of 15-20% at 343 nm. In contrast, modification of serine resulted in inhibition of CPI activity with a concomitant increase of 20% in the fluorescence intensity when complexed by the enzyme. This implies the involvement of enzyme-based tryptophan in the formation of a biologically active enzyme-inhibitor complex. The presence of anti-fungal and anti-feedent activity on a single protein, as evidenced in pearl millet CPI, opens up a new possibility of raising a transgenic plant resistant to pathogens, as well as pests, by transfer of a single CPI gene.

Diversity in inhibitors of trypsin and Helicoverpa armigera gut proteinases in chickpea (Cicer arietinum) and its wild relatives

Developing seeds of eight chickpea (Cicer arietinum L.) cultivars (12-60 days after flowering) showed a significant variation in the trypsin inhibitor (TI) and the Helicoverpa armigera gut proteinase inhibitor (HGPI) content. For example, the highest TI (198 units/g) and HGPI (23 units/g) activities were exhibited by mature seeds of cv ICCV-2, whereas the lowest inhibitor activities were observed in cv PG8505-7 (96.1 TI units/g) and cv Vijay (5 HGPI units/g). Electrophoretic patterns showed a variation in TI bands during the early stages of seed development, indicating cultivar-specific TI accumulation. Among the seed organs, TI and HGPI activities were highly localized in the embryo-axis as compared to the cotyledons in immature and mature seeds. Moisture stress, as effected under rainfed conditions, resulted in reduced PI levels. Wild relatives of chickpea revealed variability in terms of the number and intensity of TI bands. However, when assessed for inhibition of HGP, none of the wild Cicer species showed more than 35% inhibition, suggesting that a large proportion of HGP was insensitive to PIs from Cicer. Our results provide a biochemical basis for the adaptation of H. armigera to the PIs of Cicer species and advocate the need for the transformation of chickpea with a suitable gene(s) for H. armigera resistance.

Expansion of a (GA) dinucleotide at a microsatellite locus associated with domestication in rice

Microsatellites undergo rapid changes over short evolutionary time periods which can be phylogenetically informative in related species. Here we show the repeat unit expansion of a (GA)n-type microsatellite in the process of cultivation of rice from its wild ancestors. We amplified a microsatellite locus harboring (GA)n repeats from several wild and cultivated rices. Sequencing revealed an increase in repeat number from 14 in distantly related wild rice species to 24 in the widely grown present-day indica rice cultivars.

Characterization of Helicoverpa armigera gut proteinases and their interaction with proteinase inhibitors using gel X-ray film contact print technique

Since Helicoverpa armigera is a devastating pest, an attempt was made to separate its gut proteinases and assess their diversity. Gelatin coating present on the X-ray film was used as a substrate to detect electrophoretically separated proteinases of H. armigera gut extract on native polyacrylamide gel electrophoresis (PAGE), sodium dodecyl sulfate (SDS)-PAGE and isoelectric focusing gels. The method involves electrophoresis, followed by washing the gel with Triton X-100 in case of SDS-PAGE, equilibration of the gel in proteinase assay buffers, overlaying the gel on X-ray film followed by washing the film with hot water to remove hydrolyzed gelatin revealing bands of proteinase activity. Using this protocol, at least six different proteinase isoforms were detected in H. armigera gut contents while three isoproteinases were identified in a commercial bacterial proteinase preparation. Adoption of the technique facilitated characterization of the H. armigera gut proteinases (HGP) and provided an easy tool to study the properties of the individual proteinases without purification. The approximate molecular masses of HGP as determined by SDS-PAGE were: 172.9, 59.3, 54.9, 47.6, 44.1 and 41.6 kDa, and of bacterial proteinases: 180.7, 127.3 and 95.3 kDa. The isoelectric point (pI) values of HGP and bacterial proteinase were in the range of 5.1-7.1 and 3.5-7.7, respectively. Some of the HGP isoforms were found to be highly pH-sensitive and showed activity only at pH 10.0. The major HGPs were inhibited by phenylmethylsulfonyl fluoride but not by (4-amidinophenyl)-methanesulfonyl fluoride. Incubation of HGP-resolved electrophoretic gel strips in chickpea or winged bean proteinase inhibitor solution permitted identification of specific inhibitors of individual proteinases and revealed that the major HGPs were insensitive to chickpea inhibitors whereas winged bean inhibitors effectively inhibited all the HGPs. Our results suggest that considerable variability exists among the isoproteinases of H. armigera gut with respect to their pH optima and sensitivity towards chemical and plant proteinase inhibitors. Such diversity is of immense biological significance as it explains the polyphagous nature of the insect which imparts unique adaptability to it against the defensive proteinase inhibitors of its wide range of host plants.