Direct and bystander effects in human blood lymphocytes exposed to 241Am alpha particles and the relative biological effectiveness using chromosomal aberration and micronucleus assay.

Purpose: It is important to understand the significance of alpha (α) radiation-induced bystander effects (RIBE) and its relative biological effectiveness (RBE); this is because the phenomenon is not universal and the mechanism is unclear and because the RBE is widely varying and projected to be very high. Materials and methods: Isolated lymphocytes from healthy volunteers (n = 10) were exposed to either low fluence α-particles (241Am), γ-rays (60Co), or X-rays (225 kVp and 6 MV). Co-culture methodology was employed to investigate bystander effects (BEs). Chromosomal aberrations (CA) and micronucleus (MN) formation were used to study the BE and calculated RBE. Results: Lymphocytes directly exposed to the types of radiation used showed a dose-dependent increase in the frequency of CA and MN; dose independent increases in the frequency of these chromosomal damages in co-cultured bystander cells, implies that all three types of radiation-induced a BE. The calculated RBE at the level of 5% induced aberrations varied between 9 and 20. Conclusion: The magnitude of low fluence α-particle induced RIBE is higher than in low LET (linear energy transfer) radiation. The RBE also varies depending upon the endpoints used and adds up to targeted effects. Since the endpoint of CA is considered as an important and early marker of risk prediction, the RIBE and RBE using CA as a marker are relevant for radiation protection purposes.

Study of Radon and Thoron exhalation from soil samples of different grain sizes.

The exhalation of radon (222Rn) and thoron (220Rn) from a porous matrix depends on the emanation of them from the grains by the recoil effect. The emanation factor is a quantitative estimate of the emanation phenomenon. The present study is to investigate the effect of grain size of the soil matrix on the emanation factor. Soil samples from three different locations were fractionated into different grain size categories ranging from <0.1 to 2mm. The emanation factors of each of the grain size range were estimated by measuring the mass exhalation rates of radon and thoron and the activity concentrations of 226Ra and 232Th. The emanation factor was found to increase with decrease in grain size. This effect was made evident by keeping the parent radium concentration constant for all grain size fractions. The governing factor is the specific surface area of the soil samples which increases with decrease in grain size.

A REVIEW ON VARIATION OF NATURAL RADIOACTIVITY ALONG THE SOUTHEAST COAST OF TAMIL NADU FOR THE PAST 4 DECADES (1974-2016).

This review deals with natural radioactivity variation along the southeast coast of Tamil Nadu for the past four decades (1974-2016). About 40 research works have been conducted along the coast since 1974 in various environmental matrices using a variety of experimental methods. For these measurements researchers are adopted different experimental methods. The measured gamma dose rate ranged from 30 to 8700 nGy/h. The mean specific activity of 238U, 232Th and 40K was found to be 58.8 ± 28.7, 465.2 ± 147.3 and 311.2 ± 27.8 Bq/kg, respectively. The calculated annual exposure rate ranged from 0.29 to 12.8 mSv/y with the mean value of 3.7 mSv/y which is above the global average of 2.4 mSv/y as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (Report to General Assembly, Annex B Exposures of the public and workers from various sources of radiation. United Nations, New York (2008)). Plant food items recorded low 210Po activities as compared to seafood organisms. Grain size, season and place of sampling have a decisive bearing on coastal radioactivity. Therefore, it is concluded from the review data that there is an appreciable elevation in background radiation level in the coastal region. This review suggests that new radiological surveys using improved methodology that cover the entire coastal stretch are needed.

Comparison of dicentric dose response curves of 6MV LINAC X-rays and 60Co γ-rays for biodosimetry application.

In vitro Dicentric (DC) dose response curves of 6MV X-rays (3Gy/min) and 60Co γ-rays (0.63Gy/min) were generated and compared (intra-laboratory) to understand their similarities and differences. Human peripheral blood samples exposed to ten different doses (0, 0.05, 0.1, 0.25, 0.5, 1, 2, 3, 4 and 5Gy) of 6MV X-rays and 60Co γ-rays were subjected to Dicentric Chromosome Assay (DCA) and dicentrics, excess acentric fragments (AF) and chromatid breaks (CB) were scored. Totally about 31,553 metaphase spreads were scored for the purpose. Dose response curves of both radiation qualities were almost same except for a 13.8% higher ß value for 6MV X-rays. However, blind tests results revealed that both these curves are biologically equivalent and exhibited good dose prediction accuracy for the entire dose range. This demonstrated the feasibility of interchangeable use of these curves in biodosimetry. Consequently it has been suggested that LINAC facilities worldwide can be roped in for biodosimetry capacity augmentation towards managing nuclear emergency situations involving γ-radiation exposures.

Nucleoplasmic bridges as a biomarker of DNA damage exposed to radon.

Radon is a naturally occurring radionuclide in the environment, during decay it emits high linear energy transfer (LET) alpha particles. When radon exposure is accompanied by smoking it has been reported that lung cancer risk is higher. Blood samples were collected after prior consent, 25 smokers and 25 non smokers (only males) exposed in vitro to radon gas with doses ranging between 0.3-12.6mGy Ionizing radiation is a strong clastogenic agent and a potent inducer of MN. Cytokinesis-Blocked Micro Nucleus (CBMN) assay has proven to be a reliable, thoroughly validated and standardised technique in the field of radiation biology. In view of this, an invitro study has been undertaken using CBMN assay to suggest Nucleoplasmic bridges (NPBs) as a potential bio-dosimeter and to investigate the existence of a possible influence of smoking on genetic damage induced by ionizing radiation. The mean percentages frequencies of micronuclei, nucleoplasmic bridges and nuclear buds among the exposed smoker group were 4.82±0.271, 0.6±0.04 and 0.12±0.02 respectively and these values for exposed non-smoker group were 2.78±0.285, 0.4±0.04 and 0.06±0.01 respectively. Spearman rank correlation for the frequency of nucleoplasmic bridge with respect to dose was considered to be significant (P<0.05) in non-smokers. This study is first of its kind to investigate NPB as a biomarker of early DNA damage induced by radon.

Dicentric assay: inter-laboratory comparison in Indian laboratories for routine and triage applications.

An Inter-Laboratory Comparison (ILC) study on Dicentric Chromosome Assay (DCA) was carried out between two Indian biodosimetry labs. Human peripheral blood samples exposed to 10 different doses of X-rays up to 5Gy were shared between the labs to generate calibration data. Validation of calibration curves was done by dose estimation of coded samples exposed to X- or gamma radiation. Reliability of the DCA data for triage application was evaluated by scoring 20, 50 and 100 metaphases in the dose range of 0.5-3.0Gy. No significant difference was observed between labs regarding the established calibration data as well as the DCA triage dose assessments. Scoring of 20 metaphases (MP) was adequate to detect radiation exposure of >2Gy whereas 50 MP were sufficient to determine exposures of 0.5Gy. Both labs performed the DCA in a reliable manner and made the first step in setting up a biodosimetry network in India.

Adsorption of uranium from aqueous solution by PAMAM dendron functionalized styrene divinylbenzene.

A new polymeric chelating resin was prepared by growing third generation poly(amido)amine (PAMAMG3) dendron on the surface of styrene divinylbenzene (SDB) and characterized by FTIR, TGA and SEM. The ideal branching of dendron in the chelating resin was determined from potentiometric titration. Adsorption of uranium (VI) from aqueous solution using PAMAMG3-SDB chelating resin was studied in a series of batch experiments. Effect of contact time, pH, ionic strength, adsorbent dose, initial U(VI) concentration, dendron generation and temperature on adsorption of U(VI) were investigated. Kinetic experiments showed that U(VI) adsorption on PAMAMG3-SDB followed pseudo-second-order kinetics model appropriately and equilibrium data agreed well with the Langmuir isotherm model. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) were evaluated from temperature dependent adsorption data and the uranium adsorption on PAMAMG3-SDB was found to be endothermic and spontaneous in nature. The sticking probability value (5.303 × 10(-9)), kinetic and isotherm data reveal the chemisorption of uranium on PAMAMG3-SDB and adsorption capacity of the chelating resin was estimated to be 130.25 mg g(-1) at 298 K. About 99% of adsorbed U(VI) can be desorbed from PAMAMG3-SDB by a simple acid treatment suggesting that the chelating resin is reusable.

Case series study of the clinical profile of H1N1 swine flu influenza.

OBJECTIVES: To study the clinical profile of the H1N1 influenza cases attending government hospitals in South India and to study the impact of H1N1 infection on pregnancy outcome. MATERIALS AND METHODS: A total number of 442 H1N1 positive patients (198 inpatients and 244 outpatients) from two government hospitals in Chennai, Madras Medical College & Government General Hospital and Institute of Child Health, Egmore were studied retrospectively during a period of 6 months from August 2009 to January 2010. RESULTS: The rate of reported cases and hospitalization rates was highest among individuals aged 5 to 24 years. H1N1 cases were equally distributed in both the sexes in the adult population In our study 86.92% percent of patients with pandemic H1N1 influenza A met the case definition for influenza like illness (subjective fever plus cough and/or sorethroat). Similar to the western data bronchial asthma, pulmonary tuberculosis were found to risk factors for complications in H1N1 infection. The overall mortality rate was 1.8% and the most common cause of death in patients was due to pneumonia. Ventilator requirement was associated with poor prognosis in H1N1 patients. P value < 0.01. The percentage of persons > 65 years who were affected was far less ie 0.67% which is quite unusual in the case of seasonal flu. H1N1 pnuemonia was found to involve predominantly the lower lobe of lung. (p value < 0.01).The mortality rate among pregnant women with H1N1 infection was 25% and the fetal loss rate was 16.67%. There was an increased risk of H1N1 influenza infection during the third trimester of pregnancy. (p value-0.027). CONCLUSIONS: Individuals with comorbid conditions, pregnancy were found to be severely affected. Hence individuals with risk factors need to be protected by vaccination.

Should a school honor a student's DNR order?

Physicians first present the case of a sixteen-year-old cardiac patient who has refused a heart transplant and cardiac resuscitation. Her family and physicians accept the decision. The family has asked the school system to honor her do not resuscitate order if she goes into cardiac arrest in school The school system has refused to do so. Following the case presentation, a lawyer, a physician/ethicist, and an educator consider the important issues raised by this ongoing case.

Pseudohypoaldosteronism.

Shortly after birth, a 1,860-g premature male newborn with respiratory distress syndrome had brisk diuresis, rapid weight loss, and severe hyponatremia despite aggressive Na+ and fluid replacement. The serum cortisol level was normal, and the 17-OH progesterone concentration was low. He did not show any response to treatment with dexamethasone and desoxycorticosterone acetate. Results of renal function studies were within the normal range for his gestational age. The serum aldosterone level and plasma renin activity were grossly elevated, confirming the diagnosis of pseudohypoaldosteronism. This uniquely early and dramatic presentation was attributed to immaturity of the proximal renal tubule at 32 weeks' gestation. The subsequent improvement paralleled the rapid maturation of the kidney after birth.

Nonoliguric acute renal failure in the newborn: a prospective evaluation of diagnostic indexes.

Fifteen newborn babies with azotemia without oliguria were studied. Group A infants had increased BUN levels and decreased creatinine clearance (Ccr) for gestational and postnatal age, and were compared with group B infants, who had increased BUN levels and normal Ccr. The Ccr was 0.35 mL/min in group A and 0.76 mL/min in group B. Urine volume during the same period was 2.45 mL/kg/hr in group A and 4.66 mL/kg/hr in group B. No significant differences in fractional sodium excretion; urine to plasma ratios of creatinine, osmolality, and sodium; and renal failure index were present between the two groups. The results suggest that nonoliguric acute renal failure is a diagnostic entity in the newborn. The Ccr is the most useful indicator for defining renal function in the presence of azotemia and normal urine volume.

Evolution of porencephalic cysts from intraparenchymal hemorrhage in neonates: sonographic evidence.

Ninety-four low-birth-weight neonates were screened consecutively with real-time sonography for evidence of cerebroventricular hemorrhage. Among them, 13 were found to have intraparenchymal hemorrhage beyond the area of the germinal matrix. Weekly follow-up sonograms revealed progression to porencephaly in every surviving infant. Four different sonographic patterns were observed during the evolution from the original hemorrhage to the porencephalic cyst. The size of the mature porencephalic cyst correlated directly with the size of the intraparenchymal hemorrhage. After ventriculoperitoneal shunting, the porencephalic cysts became smaller or remain unchanged. One small cyst was no longer identified after successful shunting, but reappeared with shunt failure.

Congenital esophageal atresia: lipase activity is present in the esophageal pouch and stomach.

Lipolytic activity was studied in aspirates from the esophageal pouch and from the stomach of eight infants with congenital esophageal atresia. Lipolytic activity, tested with doubly labeled ([3H]glyceryl, [14C]fatty acid) long-chain triglyceride was present in esophageal and gastric aspirates. The activity in esophageal aspirates was in the range of 2.7-130 nmol/min/ml aspirate and that in gastric aspirates was in the range of 2.9-40.4 nmol/min/ml aspirate. The reaction products of lipolytic activity in esophageal and gastric aspirates were a mixture of mono- and diglycerides, glycerol, and free fatty acids. The lipolytic activity at the two sites--esophagus and stomach--varied with respect to pH optimum (5.0-7.6 and 6.0-6.5, respectively) and reaction products (glycerol 41.6 +/- 20% and 7.3 +/- 4.6%, respectively). These findings confirm the earlier observations that digestion of dietary fat is initiated in the stomach and suggest that the lipolytic activity present in gastric contents originates concomitantly from the oral-esophageal area as well as from the stomach. These studies do not exclude the possibility that the lipolytic activity in the stomach of infants with esophageal atresia could originate in regurgitated intestinal contents.

Real-time ultrasonography of neonatal intraventricular hemorrhage and comparison with computed tomography.

Thirty-three low-birth-weight neonates were diagnosed prospectively as having an intraventricular hemorrhage, using a real-time sonographic sector scanner. Ultrasound findings were corroborated in 27 patients by computed tomography (CT) or autopsy. Intraventricular blood is hyperechoic and, in a fresh hemorrhage, a continuous cast-like pattern of increased echogenicity replaces the usually minute, echo-free lateral ventricles. After one to three days, the lateral ventricles begin to enlarge around the echogenic clot if hydrocephalus complicates the hemorrhage. The sonographic findings indicating intraventricular hemorrhage and its progression to hydrocephalus are presented. The accuracy of sonographic real-time sector scanning in the evaluation of neonatal intraventricular hemorrhage is discussed and compared to CT.

Postheparin lipolytic activity and Intralipid clearance in very low-birth-weight infants.

The effect of heparin (10 U/kg) on serum lipolytic activity, triglyceride and FFA levels, during four hours infusion of 0.5 gm/kg Intralipid was measured in 18 AGA infants, 25 to 32 weeks' gestational age. PHLA, TG, and FFA were measured at 0, 10, 30, 120, and 240 minutes of infusion of Intralipid, before and following a bolus of 10 U/kg heparin iv. Lipolytic activity, measured by hydrolysis of activated tri-3H-oleate and expressed in mumol FFA released per milliliter serum per hour, was not detected in serum before heparin administration. Ten minutes after heparin administration peak PHLA was significantly higher in infants of 27 to 32 weeks' gestation than in infants of 25 to 26 weeks' gestation. There was no significant difference in peak PHLA between infants of 27 to 28 and 29 to 32 weeks' gestation. PHLA returned to baseline (zero) two hours after heparin administration in all infants. Infants of 25 to 26 weeks' gestational age had significantly higher concentrations of serum triglycerides before and during Intralipid infusion than in infants of 27 to 32 weeks' gestational age. Although there was a transient rise in FFA 10 and 30 minutes after heparin administration, the levels of FFA and triglycerides were not different at the end of infusion with or without heparin in either group, suggesting that a single bolus of heparin has only a transient effect on Intralipid clearance.

Real-time sonography of the neonatal and infant head.

Fifty neonatal and infant heads were examined using a 5 MHz real-time sector scanner. Anatomic detail superior to that previously described was achieved by this method. Normal structures routinely imaged included the entire ventricular system and many parts of the subarachnoid spaces. The gray scale detail of parenchymal structures was usefully demonstrated. Routinely visualized vascular structures included the anterior cerebral artery system, the middle cerebral arteries, the choroid plexus, and the posterior cerebral arteries. Hydrocephalus, as well as intraventricular hemorrhage and its sequelae, were investigated. Computed tomography (CT) is considered diagnostic in hydrocephalus and intraventricular hemorrhage, but evaluation by sonography compares favorably. Among other advantages of sonography are the feasibility of bedside scans without removing the patient from the intensive care nursery and the elimination of ionizing radiation.

Behavioral and dermatologic changes and low serum zinc and copper concentrations in two premature infants after parenteral alimentation.

Two premature infants were observed to develop behavioral and dermatologic changes and low serum zinc and copper concentrations following cessation of prolonged parenteral alimentation, while being fed exclusively with human milk. Following treatment with exogenous oral zinc supplementation, prompt relief of symptoms and increases of serum zinc and copper concentrations were observed in both infants. These patients comprise about 5% of our premature infants who are treated with parenteral alimentation for more than two weeks. We recommend that premature infants on prolonged parenteral alimentation should be monitored for changes in serum zinc and copper concentrations and, if a marked fall is observed, supplementation should be considered.

Fat digestion in the stomach of premature infants. I. Characteristics of lipase activity.

Lipolytic activity was studied in gastric aspirates of 13 premature infants of birth weight 1,050 to 1,786 gm. All infants received a diet of infant formula fed by gastric tube. Gastric aspirates were collected after irrigating the stomach with 2 to 5 ml sterile saline before regular feeding. Lipolytic activity, tested with doubly labeled 3H glyceryl-14 C tripalmitin substrate, was 55.6 +/- 11.7 n mol/min/ml (range 4.2 to 140). The lipolytic activity had a pH optimum of 5.4 and produced partial glycerides (mono and diglycerides), glycerol, and free fatty acids. Lipolysis was inhibited by bile salts. Our findings show that in premature infants, as in adults, digestion of dietary fat starts in the stomach. Since bile salt concentrations are low in premature infants, the amphiphilic reaction products formed (monoglyceride and FFA) could play a significant role in the stabilization of lipid emulsions.