Histomorphometric and Immunohistochemical Diagnosis of Renal Cell Carcinoma: Review Article.

Renal cell carcinoma (RCC) is derived from renal tubular epithelial cells and is among the 10 most common cancers worldwide. Incidence of renal cell carcinoma is 400,000 individuals worldwide per year. The age of diagnosis is approximately 60years, and twice as many men are diagnosed as women. African Americans have a slightly higher rate of RCC than do White peoples. The reasons for this are not clear. Inherited syndromes in family, long term dialysis, smoking individuals who had quit smoking >10 years prior had a lower risk when compared to those who had quit <10 years. 22.5 pack-year smokers had a more than 50.0% increased RCC risk compared to nonsmokers, high body mass index i.e. 5kg/m2 increase in body mass index (BMI) was found to be strongly associated with RCC. BMI >35kg/m2 is associated with higher incidence of Cancer raise blood pressure- Higher BMI and hypertension were independently shown to increase the long-term risk of RCC in men. A rise of blood pressure of 10mmHg is associated with 10-22 percent risk of RCC. Clear cell carcinoma is the most common variety of renal cell carcinoma as compared to other varieties of renal cell carcinomas (68.0-75.0%). It has also been found that CAIX is positive for all papillary renal cell carcinoma and negative for CK7, AMACR & TEF. We also found that CK7, EMA, CD117 and CAIX are most commonly positive for all chromophobe renal cell carcinoma. It has been found that clear cell carcinoma is the most common variety of renal cell carcinoma as compared to other varieties of renal cell carcinomas (68.0-75.0%). Again it has also been found that CAIX is positive for all papillary renal cell carcinoma and negative for CK7, AMACR and TEF. Here it has been found that chromophobe carcinoma is most commonly positive for CK7, EMA, CD117 and CAIX. In a patient coming with signs and symptoms of renal cell carcinoma can be confirmed with the help of histoimmunological markers and in that case one can plan for a proper planning of management.

Conventional vs virtual autopsy with postmortem MRI in phenotypic characterization of stillbirths and fetal malformations.

OBJECTIVE: To compare virtual autopsy using postmortem magnetic resonance imaging (MRI) with conventional autopsy with respect to phenotypic characterization of stillbirths and malformed fetuses, and acceptability to parents. METHODS: This was a prospective diagnostic evaluation study, conducted from June 2013 to June 2015, including stillbirths and pregnancies terminated owing to fetal malformation at ≥ 20 weeks' gestation, for which parental consent to both conventional autopsy and postmortem MRI was obtained. Cases of maternal and obstetric cause of fetal demise were excluded. Whole-body postmortem MRI (at 1.5 T) was performed prior to conventional autopsy. Taking conventional autopsy as the diagnostic gold standard, postmortem MRI findings alone, or in conjunction with other minimally invasive prenatal and postmortem investigations, were assessed and compared for diagnostic accuracy. RESULTS: Parental consent for both conventional autopsy and postmortem MRI was obtained in 52 cases of which 43 were included in the analysis. In 35 (81.4%) cases, the final diagnosis based on virtual autopsy with postmortem MRI was in agreement with that of conventional autopsy. With conventional autopsy as the reference standard, sensitivity, specificity, positive and negative predictive values of postmortem MRI were, respectively: 77.7%, 99.8%, 97.4% and 98.0% for whole-body assessment; 93.1%, 99.0%, 87.1% and 99.5% for the nervous system; 61.0%, 100.0%, 100.0% and 96.7% for the cardiovascular system; 91.1%, 100.0%, 100.0% and 98.0% for the pulmonary system; 80.6%, 99.8%, 96.7% and 98.7% for the abdomen; 96.2%, 99.7%, 96.2% and 99.7% for the renal system; and 66.7%, 100.0%, 100.0% and 97.2% for the musculoskeletal system. Virtual autopsy was acceptable to 96.8% of families as compared with conventional autopsy to 82.5%. CONCLUSIONS: Virtual autopsy using postmortem MRI and other minimally invasive investigations can be an acceptable alternative to conventional autopsy when the latter is refused by the parents. Postmortem MRI is more acceptable to parents and can provide additional diagnostic information on brain and spinal cord malformations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Seroepidemiology and molecular characterization of hepatitis E virus infection in swine and occupationally exposed workers in Punjab, India.

Hepatitis E virus (HEV) has two discrete epidemiological patterns: waterborne epidemics in developing countries only, caused by HEV genotype I, and sporadic zoonotic outbreaks in developing and developed countries caused by genotypes III and IV. This study was designed to investigate seroprevalence, molecular detection and the characterization of HEV by nested RT-PCR in swine as well as the occupational risk to exposed human population in Punjab state of north-western India. The occupational risk-exposed group comprised of swine farmers (organized - mixed feed feeders and unorganized - swill feeders), slaughterhouse workers, sewage workers and veterinary internes. During the study period, blood and faecal samples were collected from 320 swine and 360 humans with both high and low occupational exposure risks. The overall seroprevalence of swine HEV was 65.00%, with a significantly higher seropositivity in growing pigs (2-8 months of age). The prevalence of HEV RNA in swine faecal samples by nRT-PCR was 8.75% with a significantly higher detection in swill-fed pigs. With humans in the high occupational exposure risk population, significantly higher anti-HEV IgG seropositivity was observed (60.48%) as compared to control population (10.71%). Strong evidence of association between human anti-HEV IgG seropositivity and certain occupational exposure risk groups was observed (p < 0.05). This indicates that unorganized swine farmers, slaughterhouse workers and sewage workers have higher odds of HEV infection in this study region. Percentage of nucleotide similarity between swine and human HEV isolates was less than that found in countries with zoonotic HEV outbreaks. Molecular characterization revealed the circulation of G IV and G I genotypes among swine and human population in Punjab state, respectively.

What a difference a day makes: same-day vs. 2-day sputum smear microscopy for diagnosing tuberculosis.

Setting: Nine district-level microscopy centres in Assam and Tripura, India. Objective: Same-day sputum microscopy is now recommended for tuberculosis (TB) diagnosis. We compared this method against the conventional 2-day approach in routine programmatic settings. Methods: During October-December 2012, all adult presumptive TB patients were requested to provide three sputum samples (one at the initial visit, the second 1 h after the first sample, and the third the next morning) for examination by Ziehl-Neelsen smear microscopy. Detection of acid-fast bacilli with any sample was diagnostic. The first and second spot sample comprised the same-day approach, and the first spot sample and next-day sample comprised the 2-day approach. Results: Of 2168 presumptive TB patients, 403 (18.6%) were smear-positive according to the same-day method compared to 427 (19.7%) by the 2-day method (McNemar's test, P < 0.001). Of the total 429 TB patients, 26 (6.1%) were missed by the same-day method and 2 (0.5%) by the 2-day method. Conclusion: Same-day specimen collection for microscopy missed more TB than 2-day collection. In India, missing cases by using same-day microscopy would translate into a considerable absolute number, hindering TB control efforts. We question the indiscriminate switch to same-day diagnosis in settings where patients reliably return for testing the next day.

Contexte : Neuf centres de microscopie de district dans les états d'Assam et de Tripura, Inde.Objectif : On recommande maintenant une microscopie de frottis le même jour pour le diagnostic de la tuberculose (TB). Nous avons comparé cette méthode par rapport à l'approche conventionnelle en 2 jours dans un contexte de programme de routine.Méthodes : Entre octobre et décembre 2012, tous les patients adultes présumés atteints de TB ont été invités à fournir trois échantillons de crachats (lors de la visite initiale, 1 heure après le premier échantillon et le matin suivant) pour un examen par microscopie de frottis selon Ziehl-Neelsen. La détection de bacilles acido-alcoolo-résistants dans un quelconque échantillon constituait le diagnostic. Les premier et deuxième échantillons ont constitué l'approche du même jour et le premier échantillon plus celui du matin suivant constituaient l'approche en 2 jours.Résultats : Sur les 2168 patients présumés TB, 403 (18,6%) étaient frottis-positifs selon la méthode du même jour comparés à 427 (19,7%) par la méthode en 2 jours (test de McNemar P < 0,001). Sur ce total de 429 patients TB, 26 (6,1%) ont été manqués par la méthode du même jour et 2 (0,5%) par la méthode en 2 jours.Conclusion : Le recueil d'échantillons le même jour pour une microscopie a manqué plus de cas de TB que le recueil en 2 jours. En Inde, une stratégie de microscopie le même jour à ce taux se traduirait par un grand nombre absolu de cas manqués, entravant les efforts de lutte contre la TB. Nous remettons en question le fait de passer sans discrimination au diagnostic du jour même dans des contextes où les patients reviennent de manière fiable pour un test le jour suivant.

Marco de referencia: Nueve centros distritales de microscopia de Assam y Tripura en la India.Objetivo: Actualmente se recomienda en el diagnóstico de la tuberculosis (TB) practicar la baciloscopia del esputo el mismo día de la consulta. En el presente estudio se comparó este método con la estrategia corriente de baciloscopia en dos días que se aplica en las prácticas programáticas.Métodos: De octubre a diciembre del 2012 se solicitó a todos los adultos con presunción diagnóstica de TB que aportaran tres muestras de esputo (en el momento de la consulta inicial, una hora después y a la mañana siguiente), con el fin de practicar el examen microscópico con la coloración de Ziehl-Neelsen. El criterio diagnóstico fue la detección de bacilos acidorresistentes en cualquiera de las muestras. La primera y la segunda muestras inmediatas constituyeron la estrategia del mismo día y la primera muestra inmediata y la muestra del día siguiente constituyeron la estrategia de 2 días.Resultados: En los 2168 pacientes con presunción de TB, se confirmó el diagnóstico en 403 casos (18,6%) con el método del mismo día y en 427 (19,7%) con la estrategia de 2 días (prueba de McNemar P < 0,001). Del total de 429 pacientes con diagnóstico de TB, se pasaron por alto 26 casos cuando se recogieron las muestras el mismo día (6,1%) y 2 casos cuando se recogieron durante 2 días (0,5%).Conclusión: La recogida de muestras destinadas a la baciloscopia en el mismo día omitió el diagnóstico de más casos de TB que la recogida de muestras en 2 días. En la India, pasar por alto el diagnóstico de casos con el examen microscópico realizado el mismo día tendría como consecuencia omitir una cifra absoluta de pacientes muy alta, que entorpecería los resultados de las iniciativas de control de la TB. En el presente artículo se pone en duda la utilidad de un cambio indiscriminado hacia el método de diagnóstico en el mismo día, en los entornos donde se puede confiar en que los pacientes regresarán al día siguiente para completar las muestras de esputo.

Gastrointestinal nematode larvae in the grazing land of cattle in Guwahati, Assam.

AIM: To know the prevalence of gastrointestinal nematode larvae (L3) in the grazing land of cattle in Guwahati, Kamrup district, Assam. MATERIALS AND METHODS: Pastures were collected and examined for the presence of nematode larvae (L3) from six localities of Guwahati at monthly interval from August 2012 to July 2013. The counted larvae were then expressed as per kg dry matter of herbage (L3/kg DM). RESULTS: Examination of pastures revealed presence of nematode larvae (L3) in pastures throughout the year which varied from 4.5 L3/kg DM in January to a maximum of 106.33 L3/kg DM in August. The L3 of Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp., Cooperia spp., and Mecistocirrus spp. were recovered from pastures. The average pasture larval burden (PLB) was 34.75±3.48 L3/kg DM. Season-wise PLB revealed the presence of 23.89±3.01, 67.54±5.41, 26.67±1.92, and 7.28±0.89 L3/kg DM during pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. Monsoon season has significant (p<0.05) effect on PLB. However, analysis of variance of different locations with respect to season revealed that there was no significant difference but season-wise it was highly significant (p<0.01). Pearson correlation of environmental variables (temperature, relative humidity, and rainfall) with PLB revealed correlation was statistically significant with rainfall (p<0.05). CONCLUSION: This study reveals the presence of five nematode larvae (L3) in the pastures of Guwahati, Assam throughout the year, statistically significant during monsoon season.

Diversity of Eimeria spp. in dairy cattle of Guwahati, Assam, India.

AIM: To determine the prevalence and diversity of Eimeria spp. in dairy cattle present in and around Guwahati, Kamrup district, Assam, India. MATERIALS AND METHODS: A total of 2339 fecal samples of calves (535), heifer (641) and adult (1163) cattle were screened for 1 year present in and around Guwahati, Assam for detection of Eimeria oocysts by flotation techniques. Sporulation of the oocyst was done in 2.5% potassium dichromate solution for identification of the Eimeria species. RESULTS: Examination of fecal samples revealed an overall prevalence of 11.97% Eimeria infection in dairy cattle of Guwahati, Assam. Age-wise, 33.2%, 45.4%, and 21.4% infections were recorded in calves (<1 year), heifer (1-3 years) and adult (>3 years) cattle, respectively. Season-wise, infection was recorded highest during post-monsoon (16.29%), followed by monsoon (15%), winter (9.44%), and pre-monsoon (7.49%) season. Seven species of Eimeria were recorded viz. Eimeria bovis, Eimeria zuernii, Eimeria subspherica, Eimeria bukidnonensis, Eimeria auburnensis, Eimeria ellipsoidalis and Eimeria alabamensis. The oocyst count per gram of feces ranged from 50 to 1500 in infected cattle. CONCLUSION: This study indicates that there is the prevalence of seven species of Eimeria in dairy cattle of Guwahati, Assam and mostly prevalent during the post-monsoon season.

Comparison of diagnostic tests for diagnosis of infectious bovine rhinotracheitis in natural cases of bovine abortion.

Rapid and precise diagnosis plays a pivotal role in implementing suitable control measures in natural field cases of bovine abortion due to infection with bovine herpesvirus (BHV)-1. In the present study, serology, virus isolation, histopathology, immunohistochemistry (IHC) and real-time polymerase chain reaction (PCR) for amplification of the gene encoding glycoprotein B were applied for diagnosis of infectious bovine rhinotracheitis (IBR) in cases of abortion. The seroprevalence of IBR in the population studied was 26.3% as determined by indirect enzyme-linked immunosorbent assay. BHV-1 abortions occurred between 4 and 8 months of gestation with an average gestational age of 6 months. Affected placentae showed necrosis of chorionic villi and of the endothelium of small villous blood vessels with characteristic intranuclear (IN) acidophilic inclusion bodies. Similar inclusions were also seen in most of the tissues examined. BHV-1 antigen was identified immunohistochemically in necrotic foci in the liver, the endothelium of placental blood vessels, the bronchial epithelium and hepatocytes. Lesions in the brain also had IN inclusion bodies that labelled positively by IHC. Eighteen samples (nine of stomach content, two of placental cotyledons, five of pooled fetal tissue and two of vaginal discharge) out of 84 tested were positive by real-time PCR for BHV-1.

Analysis of telomere length in couples experiencing idiopathic recurrent pregnancy loss.

PURPOSE: Telomere length plays a significant role in various disorders; however, its role in idiopathic recurrent pregnancy loss (iRPL) is not known. The objective of this study was to assess telomere length in peripheral blood leukocytes in couples experiencing unexplained recurrent pregnancy loss (iRPL). METHODS: The study included 25 couples experiencing iRPL and 20 controls. The mean relative telomere length was measured by quantitative Real Time PCR (Q-PCR) based assay, which measures the average ratio of telomere repeat copy number to a single copy gene (36B4) copy number (T/S ratio) in each sample. RESULTS: The relative leukocyte mean telomere length (T/S) in both men and women from iRPL group was significantly lower (p < 0.05) when compared to controls. A significant (P < 0.05) negative correlation was found between age and leukocyte telomere length (T/S ratio). Among the sperm parameters seminal volume was found to be negatively (r = -0.4679) associated with the telomere T/S ratio. The DNA fragmentation index of sperm showed positive correlation (r = 0.4744) with telomere length. In this preliminary study, we found that shorter telomere length in both men and women may be associated with early pregnancy loss. CONCLUSION: In conclusion, shorter telomere length in both male and female partners appears to play a role in the idiopathic recurrent pregnancy loss. Loss of telomeric DNA due to oxidative stress needs further analysis. Analysis of telomere length in germ cells are needed to further substantiate the findings of this study.

Cytogenetic, Y chromosome microdeletion, sperm chromatin and oxidative stress analysis in male partners of couples experiencing recurrent spontaneous abortions.

PURPOSE: Etiology in majority of couples experiencing recurrent spontaneous abortions (RSA) is still unknown. The aim of the study was to find the role of cytogenetic abnormalities, Y chromosome microdeletion, oxidative stress (OS) and sperm DNA fragmentation in male partners of couples experiencing RSA. METHODS: Forty-eight couples with history of RSA and 20 fertile controls were included in the study. The study subjects were divided into male partners of RSA couples with abnormal sperm parameters (SA) (N = 16), male partners of RSA couples with normal sperm parameters (NS) (N = 32) and age-matched fertile controls with normal sperm parameters (FC) (N = 20). RESULTS: One of 48 men (2%) showed 46, XY (1qh-) chromosomal complement. None of the cases including FC showed deletion in any of the 3 AZF loci on Y chromosome long arm. Sperm count was found be significantly lower in SA cases as compared to group NS cases (P < 0.0001) and FC (P < 0.005). Sperm forward motility was found to be significantly (P < 0.05) lower in SA cases as compared to NS and FC. Male partners of RSA couples with abnormal sperm parameters had higher reactive oxygen species (ROS) levels (P < 0.005) and sperm DNA damage (P < 0.0001), however, in male partners of RSA couples with normal sperm parameters had only increased (P < 0.0001) sperm DNA damage. CONCLUSION: Other than chromosomal anomalies, sperm DNA fragmentation and seminal OS may be the underlying pathology in RSA, thus screening for seminal ROS levels and DNA fragmentation has diagnostic and prognostic capabilities.

The obstetric outcome following treatment in a cohort of patients with antiphospholipid antibody syndrome in a tertiary care center.

BACKGROUND: Antiphospholipid antibody syndrome (APAS) is regarded as the most frequently acquired risk factor for thrombophilia. The obstetric manifestations of APAS include early or late pregnancy losses and complications like preeclampsia and fetal growth restriction. Its timely diagnosis and treatment can improve maternal and neonatal outcome. AIMS: To study the pregnancy outcome of patients with APAS treated with heparin and aspirin. SETTINGS AND DESIGN: This was a retrospective study of pregnancy outcome in 42 consecutive women with APAS, treated with heparin and aspirin. MATERIALS AND METHODS: The case records of 42 diagnosed cases of APAS with pregnancy, over a 3-year period, were studied. The pregnancy outcome in this group was compared before and after treatment with heparin and low-dose aspirin in terms of abortions, intrauterine deaths and live birth rate. The outcome of the present pregnancy in terms of fetal and maternal complications was analyzed. RESULTS: The mean age and average parity of women with APAS were 30.1±4.1 years and 3.2±1.2, respectively. Among the treated patients of APAS, 13 (30.9%) had preeclampsia and 9 (21.4%) had intrauterine growth restriction (IUGR). There were 2 (4.7%) intrauterine deaths, 4 (9.5%) missed abortions and 3 (7.1%) abruptio placentae. Women with APAS had a live birth rate of 4.6% before treatment and 85.7% in the index pregnancy after treatment. CONCLUSION: Treatment of pregnant women with APAS results in marked improvement in the live birth rate (4.6-85.7%). However, complications like preeclampsia and IUGR occur even after treatment, requiring strict monitoring and timely delivery.

Antimicrobial activities of tocklai vegetative tea clones.

Thirty-one Tocklai vegetative (TV) tea clones contained caffeine and total catechin 44.39 and 227.55 mg/g dry weight of leaves, respectively. The (-)-epigallocatechin gallate (EGCG) was the most abundant (109.60 mg/g) followed by -(-)-epigallocatechin (EGC, 44.54 mg/g), (-)-epicatechin gallate (ECG, 41.74 mg/g), (-)-epicatechin (EC, 27.42 mg/g) and +catechin (4.25 mg/g). Total catechins were highest in TV 20 (509.7 mg/g) and lowest in TV 6 (71.7 mg/g). The tea clones that contain high level of total catechin exhibited the strongest antimicrobial activity. Among caffeine and flavanol compounds, theaflavins (TF) present in black tea possess a similar antimicrobial potency as EC present in fresh leaves, and that the conversion of catechins to TF during fermentation in making black tea tends to alter their antimicrobial activities. The bioactive molecules other than catechins present in tea leaves may also contribute towards antimicrobial activity.

Rare finding of 2n/4n mixoploidy in mother and fetus with severe immune hydrops.

The findings of diploid-tetraploid mosaicism in cultured amniotic fluid cells is considered a culture artifact. On rare occasions its presence indicates a chromosomally abnormal fetus with multiple congenital defects. We present here a patient who in her previous pregnancies had delivered one hydrops and two macerated fetuses. The reported pregnancy also resulted in a fetus with severe hydrops. Cytogenetic analysis of cultured amniotic fluid cells revealed diploid-tetraploid mosaicism in the fetus also confirmed in fetal cord blood and skin fibroblasts. Chromosomal analysis of the parents revealed mixoploidy in the mother. These findings are extremely important for prenatal diagnosis and prompt us to not uniformly dismiss tetraploidy as artifactual but to confirm it especially in cases with ultrasound abnormalities.

Molecular characterization of field isolates and vaccine strains of infectious bursal disease virus.

The present investigation was conducted to study the genetic heterogenicity and molecular polymorphism among the field isolates and vaccine strains of infectious bursal disease virus (IBDV). Samples of bursa of Fabricius from 15 suspected outbreaks of infectious bursal disease (IBD) were subjected to agar gel precipitation test (AGPT), virus isolation and reverse transcription-polymerase chain reaction (RT-PCR) combined with restriction fragment length polymorphism (RFLP). Nine out of 15 samples were found positive in AGPT while 14 were found positive both by virus isolation and RT-PCR. PCR amplified 474bp fragment from the variable region of VP2. Sac I, Stu I, Alu I, Ssp I and Mbo I restriction enzymes were used for characterization of all the 14 IBDV isolates and four reference vaccine strains. Sac I, Stu I, Alu I and Ssp I could differentiate classical virulent IBD (cvIBD) vaccine virus strains from very virulent IBD (vvIBD) field isolates by their varying restriction patterns. Based on above results two field isolates (VPL and VMK) were placed in cvIBD virus group and 12 field isolates were placed in vvIBD virus group. Virus neutralisation test (VNT) using rabbit raised Georgia strain anti-serum, however, could not differentiate between cvIBD virus and vvIBD virus. It was concluded that RT-PCR combined with RFLP assay using restriction enzymes Sac I, Stu I, Alu I and Ssp I can be used for rapid differentiation and classification of field isolates of IBDV.

Isolation and identification of antimicrobial agent-producing bacterium from Taxus baccata rhizosphere antagonistic against clinically significant microbes.

A bacterium identified as Pseudomonas fluorescence was isolated from Taxus baccata rhizosphere. Ethyl acetate extract from its culture filtrate yielded an active antimicrobial compound that was purified by TLC. The active metabolites were resolved by column chromatography on silica gel (60-120 mesh). The compound was further characterized on the basis of spectral data (UV, IR and (1)HNMR), which indicated the presence of an aromatic ring and phenolic functionality. The compound showed significant antimicrobial activity against two-gram positive bacteria (B. subtilis and S. aureus), four-gram negative bacteria (E. coli, K. pneumoniae, S. flexneri and P. aeruginosa), and one pathogenic fungus (Candida albicans). The minimum inhibitory concentration (MIC) of the compound ranged between 75µg to 250 µg/ml.

Prenatal diagnosis of haemophilia A by chorionic villus sampling and cordocentesis: all India Institute of Medical Science experience.

BACKGROUND AND OBJECTIVE: We looked at the two most commonly used methods for prenatal diagnosis, cordocentesis and chorionic villus sampling for prenatal diagnosis of haemophilia A in an Indian setting. MATERIAL AND METHODS: The study sample included 16 families which reported to us for prenatal diagnosis of haemophilia A at All India Institute of Medical Science, New Delhi, India. Prenatal tests were done on chorionic villus samples or on cord blood (cordocentesis). Molecular work-up included the use of indirect mutation analysis in the form of linkage markers like CA-13, CA-22, Xba1 and Bcl1 as well as direct mutation analysis in the form of inversion 1 and 22 detection. Non-molecular work-up included primarily factor VIII assays. RESULT: Chorionic villus sampling was performed in eight mothers. Of the other eight mothers, six underwent cord blood factor VIII assays because these had absence of family history and were negative for linkage and inversion 1 and 22. One patient had a female child and another had a fetus that showed congenital abnormalities. CONCLUSION: We found that the choice of either technique, chorionic villus or cordocentesis, is not really an alternative, but rather dependent on the gestational age of presentation.