The effect of slice thickness on target and organs at risk volumes, dosimetric coverage and radiobiological impact in IMRT planning.

PURPOSE: Dose-volume histogram (DVH) has become an important tool for evaluation of radiation outcome as reflected from many clinical protocols. While dosimetric accuracy in treatment planning system (TPS) is well quantified, the variability in volume estimation is uncertain due to reconstruction algorithm that is investigated in this study. In addition, the impact of dose distribution and tumor control probability (TCP) were also investigated with CT slice thickness for IMRT planning. MATERIALS AND METHODS: A water phantom containing various objects with accurately known volume ranging from 1 to 100 cm(3) was scanned with 1, 2, 3, 5, and 10 mm slice thickness. The CT data sets were sent to Eclipse TPS for contour delineation and volume estimation. The data were compared with known volume for the estimation of error in the volume of each structure. IMRT Plans were generated on phantom containing four objects with different slice thickness (1-5 mm) to calculate TCP. ICRU-83-recommended dose points such as D 2%, D 50%, D 98%, as well as homogeneity and conformity index were also calculated. RESULTS: The variability of volumes with CT slice thickness was significant especially for small volume structures. A maximum error of 92% was noticed for 1 cm(3) volume of object with 10 mm slice thickness, whereas it was ~19% for 1 mm slice thickness. For 2 and 3 cm(3) objects, the maximum error of 99% was noticed with 10 mm slice thickness and ~60% with 5 mm. The differences are smaller for larger volumes with a cutoff at about 20 cm(3). The calculated volume of the objects is a function of reconstruction algorithm and slice thickness. The PTV mean dose and TCP decreased with increasing slice thickness. Maximum variation of ~5% was noticed in mean dose and ~2% in TCP with change in slice thickness from 1 to 5 mm. The relative decrease in target volume receiving 95% of the prescribed dose is ~5% with change in slice thickness from 1 to 5 mm. The homogeneity index increases up to 163% and conformity index decreases by 4% between 1 and 5 mm slice thickness, producing highly inhomogeneous and least conformal treatment plan. CONCLUSIONS: Estimation of a volume is dependent on CT slice thickness and the contouring algorithm in a TPS. During commissioning of TPS and for all clinical protocols, evaluation of volume should be included to provide the limit of accuracy in DVH from TPS, especially for small objects. A smaller slice thickness provides superior dosimetry with improved TCP. Thus, the smallest possible slice thickness should be used for IMRT planning, especially when smaller structures are present.

Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions.

Rare impacted foreign bodies of larynx.

This paper presents our experience with three cases of very unusual impacted foreign bodies in larynx and all without any Classical signs and symptoms of foreign body inhalation. Review of literature reveals that these conditions are rare and reported infrequently. Correct diagnosis and adequate approach is necessary as foreign bodies that do not obstruct the airway and which are stuck in place may be relatively asymptomatic but could be life threatening.

Faunal diversity during rainy season in reclaimed sodic land of Uttar Pradesh, India.

Faunal diversity is an indicator of soil amelioration. Estimating the population size or density of an animal species in an area is fundamental to understand its status and demography and to plan for its management and conservation. Considering this, faunal diversity in reclamed sodic land was monitored during rainy season 2000-01 at different locations of district viz., Aligarh, Etah, Fatehpur, Mainpuri and Raebareli in Uttar Pradesh. The Shannon-Weiner species diversity index (H) of different fauna complex of each location was compared with zero years (1995-1996) indexes (before reclamation). Insects diversity index, in reclaimed sodic soil, varied from 3.8178 (Fatehpur: Bariyampur) to 4.623 (Fatehpur: Katoghan), which was 3.028 in zero year at Katoghan in Fatehpur 'H' index of other-arthropods ranged widely from 0.9743 (Etah: Bawali) to 2.0674 (Mainpuri: Pundari). The species diversity index of molluscs registered as high as 1.8637 at Ladhauwa site in Aligarh, which exhibited identical with Saripur site of Raebareli. 'H' index of mammal resulted with the highest (2.19) at Pundari in district Mainpuri. The avifauna and amphibian's indices were recovered maximal at Saripur site of Raebareli and Bariyampur site of Fatehpur respectively. Our result revealed that various fauna enriched with soil reclamation, which is good indicator of restoration of land, primarily due to soil-arthropods and earthworms and its eventual improvement along with succeeding rice-wheat cropping system widespread over there. It clearly shows that soil fauna strongly affects the composition of natural vegetation and we suggest that this knowledge might improve the restoration and conservation of biodiversity.

Chlorinated pesticide concentration in semen of fertile and infertile men and correlation with sperm quality.

In recent years controversy has evolved regarding the role of environmental pollutants especially chlorinated pesticides and heavy metals on male infertility. Previous data generated on the correlation of chlorinated pesticides with human semen are scarce and controversial. The objective is to explore the possibility of correlation if any between the chlorinated pesticides and sperm count and motility. Semen analysis were performed in 50 samples collected each from fertile and infertile men and pesticides estimation for dichlorodiphenyltrichloroethane (DDT) and its metabolites dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE); 1,1,1-trichloro-2,2-bis(p-chlorophenyl ethane) (pp'DDT); 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (pp'DDD), 1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (op'DDT), aldrin, hexachlorocyclohexane (HCH) isomers alpha (α), beta (ß), gamma (γ), delta (δ) were done by gas liquid chromatography. The higher concentrations of pesticide, viz. α-, ß-, γ-, δ-HCH, DDT and its metabolites (pp'DDE and pp'DDD) were detected in semen samples of infertile males. The data showed significant association between ß-HCH, γ-HCH, pp'DDE, pp'DDD with semen quality parameters.

Spindle cell sarcoma of larynx.

Spindle cell carcinoma of larynx is rare tumors constituting only 0.6% of laryngeal neoplasm with predominance in elderly males (average 63 yrs). These tumors were described under various names: pseudosarcoma, Carcinosarcoma, fibromyxosarcoma, mixed sarcoma, polypoidal sarcoma. Immunohistochemistry and electron microscopy suggest that spindle cell carcinoma are true neoplasm and spindle cells are part of the neoplasm and not benign reactive fibroblast.

Voice prosthesis - Our experience.

Malignancy of the larynx is a large group of malignancies in our country. The advanced stage of laryngeal carcinoma requires total laryngectomy which results in loss of speech along with other psychological and functional damages. Following total laryngectomy, tracheo-oesophageal voice prosthesis offers the most reliable form of voice rehabilitation. At S.M.S. Medical College and Hospital, Jaipur 25 patient underwent speech rehabilitation with voice prosthesis between Dec. 2001 to Dec. 2003. Speech rehabilitation was successful in all patients with few problem associated with indwelling prosthesis.

Correlation of chlorinated pesticides concentration in semen with seminal vesicle and prostatic markers.

Semen samples of fertile and infertile men were analysed by gas liquid chromatography (GLC) for the presence of dichlorodiphenyltrichloroethane (DDT) and its metabolites (1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene) (pp'-DDE); (1,1,1-trichloro-2,2-bis(p-chlorophenyl ethane) (pp'-DDT); (1,1-dichloro-2,2 bis(p-chlorophenyl) ethane) (pp'-DDD); (1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl) ethane) (op'-DDT), hexachlorocyclohexane (HCH) and its isomers alpha (alpha), beta (beta), gamma (gamma), delta (delta) and aldrin. The biochemical analysis of seminal vesicle and prostatic marker was done by spectrophotometer. The concentrations of alpha-, beta-, gamma-HCH, pp'-DDE and pp'-DDD were higher in the semen of infertile than in that of fertile men. An elevation in the fructose level along with decrease in the gamma-glutamyl transpeptidase and acid phosphatase activity was noticed in infertile men as compared to fertile subjects. The data showed correlation between alpha-, beta-, gamma-HCH, pp'-DDE, pp'-DDD and seminal vesicle marker fructose and prostatic marker gamma-gluatamyl transpeptidase and acid phosphatase in infertile men. The study suggests that the chlorinated pesticides may influence the semen quality by affecting the seminal and prostatic functions in infertile men.

Male reproductive toxicity of sodium arsenite in mice.

The effect of chronic oral exposure to arsenic on male mouse testicular and accessory sex organ weights, sperm parameters and testicular marker enzymes was studied. In addition, the distribution of arsenic in reproductive organs was measured using atomic absorption spectrophotometry. Sodium arsenite administered to mice (Mus musculus) via drinking water at a dose of 53.39 micromol/L (4 ppm As) for 365 days caused a decrease in the absolute and relative testicular weight. However, epididymal and accessory sex organ weight was similar to control. The activities of marker testicular enzymes such as sorbitol dehydrogenase, acid phosphatase and 17beta-hydroxy-steroid dehydrogenase (17beta-HSD) were significantly decreased, but those of lactate dehydrogenase and gamma-glutamyl transpeptidase (gamma-GT) were significantly increased. A decrease in sperm count and sperm motility, along with an increase in abnormal sperm, was observed in arsenite-exposed mice. A significant accumulation of arsenic in testes, epididymis, seminal vesicle and prostate gland was observed in treated animals. Thus long term exposure (365 days) at the dose level of 53.39 micromol/L sodium arsenite (4 ppm As), to which human beings are likely to be exposed via drinking water, may cause testicular and spermatotoxic effect.

Testicular and spermatotoxic effects of quinalphos in rats.

Testicular and spermatotoxic effects were investigated in rats exposed to technical-grade quinalphos (70%) at dose levels of 0.52 mg kg(-1) (1/50th ld(50)) or 1.04 mg kg(-1) body weight (1/25th ld(50)) for 5 days a week for 60 days. The activities of marker testicular enzymes such as sorbitol dehydrogenase (SDH) and acid phosphatase were significantly decreased but those of lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (gamma-GT) and beta-glucuronidase were significantly increased in a dose-dependent manner. This particular pattern in the activity of testicular-cell-specific enzymes, a decrease in sperm motility and total epididymal sperm count and an increase in abnormal sperm suggest damage to germ cells and Sertoli cells. The testicular and spermatotoxic effects observed in rats may be due to the pesticide quinalphos or its metabolites.

Lead and cadmium concentration in the seminal plasma of men in the general population: correlation with sperm quality.

The concentration of lead and cadmium in the seminal plasma of men in the general population, including fertile and infertile subjects, was measured. Semen samples were categorised as demonstrating oligospermia (sperm concentration < 20 x 10(6)/ml), asthenospermia (<50% motilesperm), oligoasthenospermia (a combination of the two criteria), and azoospermia (no sperm). An increase in lead and cadmium levels was observed in infertile men and there was a significant negative correlation of cadmium and lead semen concentration with sperm motility and sperm concentration in oligoasthenospermic men.

Correlation of trace mineral concentrations with fructose, gamma-glutamyl transpeptidase, and acid phosphatase in seminal plasma of different categories of infertile men.

The study describes the concentrations of zinc, magnesium, copper, iron, and biochemical markers of seminal vesicle and prostate in seminal plasma of different categories of infertile men. The zinc level in oligasthenospermic subjects was significantly higher than in azoospermic, asthenospermic, and oligospermic subjects. The gamma-glutamyl transpeptidase activity in both oligoasthenospermic and azoospermic subjects were significantly lower than in asthenospermic and oligospermic individuals. There was no significant difference in iron, copper, and magnesium levels and acid phosphatase activity among the different infertile categories. A positive correlation between zinc and acid phosphatase (r=0.84, r= 0.73; p < 0.05), and between copper and fructose (r=0.81, r=0.72; p<0.05) was observed in oligoasthenospermic and azoospermic men, respectively. On the basis of our results, it may be postulated that there is a direct effect of the trace elements zinc and copper on acid phosphatase and fructose, respectively, in oligoasthenospermic and azoospermic subjects.

Correlation of lead and cadmium in human seminal plasma with seminal vesicle and prostatic markers.

The objective of this study was to investigate the correlation between lead and cadmium with seminal vesicle and prostatic markers. Semen samples categorized into fertile and infertile were evaluated for the presence of lead and cadmium and biochemical markers in the seminal plasma. Associations between lead and fructose, acid phosphatase and gamma-glutamyl transpeptidase (gamma-GT) were observed. However, no such relationships were noticed for cadmium. It is concluded that lead may be one of the pollutants indirectly affecting semen quality by altering the functions of accessory sex glands.

Persistent chlorinated pesticides and intra-uterine foetal growth retardation: a possible association.

OBJECTIVE: To examine the association between DDT (dichlorodiphenyl trichloroethane) and HCH (hexachlorocyclohexane) exposure and intra-uterine growth retardation (IUGR, <10th percentile of birth weight for gestational age). METHOD: We detected p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE and alpha-HCH, beta-HCH, gamma-HCH, delta-HCH in maternal blood, placenta and cord blood, collected at parturition, from mothers with IUGR babies ( n=30) and from those with babies of normal weight ( n=24), using gas-liquid chromatography equipped with electron capture detector ((63)Ni). The adjusted odds ratios (ORs) for these pesticides in mothers and infants were determined by multiple logistic regression. RESULTS: There were statistically significant associations ( P<0.05) between maternal blood levels of alpha-HCH (OR=1.22; 95% CI: 1.02-1.46), gamma-HCH (OR=1.38; 95%CI: 1.05-1.80), delta-HCH (OR=1.61; 95% CI: 1.01-2.54), total HCH (OR=1.07; 95% CI: 1.01-1.13) and p,p'-DDE (OR=1.21; 95%CI:1.03-1.42) and IUGR after adjustment for potential confounders. Also, significant association (P<0.05) between cord blood levels of gamma-HCH (OR=1.14; 95% CI: 1.00-1.31), delta-HCH (OR=1.31; 95% CI: 1.00-1.75), total HCH (OR=1.07; 95% CI: 1.00-1.14) and IUGR were found after adjustment for potential confounders. A significant negative correlation between body weight of newborn babies and p,p'-DDE in maternal blood (r= -0.25; P<0.05) and delta-HCH and p,p'-DDE in the cord blood (r= -0.27 and -0.26; P<0.05) was noticed after gestational age had been accounted for. CONCLUSION: Exposure of pregnant women to organochlorine pesticides may increase the risk of IUGR, which is a contributing factor for infant mortality in India.

Relationships of maternal blood lead and disorders of pregnancy to neonatal birthweight.

Transient complications of pregnancy (anemia, toxemia, proteinuria, arterial hypertension and hyperemesis) were studied in pregnant women from the general population reporting to local hospitals. Comparison of blood lead levels (PbB) was made between women with normal pregnancies and those with complications. Significantly higher PbB were found in women with pregnancy complications as compared to those with normal pregnancies. Increments in the PbB levels were accompanied by statistically significant decrements in neonate birthweights. Complications of pregnancy may be induced by higher PbB and may also compound the adverse effects of decrements of neonate birthweights

Molybdenum in rat tissue.

Male rats were given 50 mg/kg molybdenum (Mo; as sodium molybdate) in drinking water for eight consecutive doses. The feeding of Mo was associated with an increased concentration of Mo in body tissues. The highest concentrations of metal were found in the kidney while it was least in blood cells. The accumulation was considered to be significant.

Testicular and spermatotoxic effect of nitrate in mice.

A study was conducted with nitrate to assess the testicular and spermatotoxic effects in mice at doses to which human beings are exposed as well as at higher dose levels in the drinking water. Potassium nitrate was administered to mice at dose levels 90, 200, 500, 700 and 900 ppm for 35 days. There was no difference in the uptake of water in control and treated animals. The amount of nitrate intake/ mouse/day calculated on the basis of water intake in the different groups ranged from 22.5 to 27, 50 to 60, 125 to 150, 175 to 210 and 225 to 270 mg/kg body weight. No changes were evident in the body weight, testicular, epididymal and accessory organ weight at all the dose levels tested, although a decline in sperm count and sperm motility along with an increase in abnormal sperm was noticed at 900 ppm. The activity of marker testicular enzymes, mainly 17-beta hydroxysteroid dehydrogenase (17-betaHSD) and gamma glutamyl transpeptidase (gamma-GT), associated with specific cell types were altered. Histopathological changes including atrophy and disturbed spermatogenesis were observed only at the 900-ppm dose level. In conclusion, we can say that the testicular and spermatotoxic effects are observed only at the highest dose level, which is not likely to be encountered in the drinking water.

Some essential elements in maternal and cord blood in relation to birth weight and gestational age of the baby.

Maternal and cord blood were collected from 54 Indian women at parturition and analyzed for Zn, Cu, and Fe by flame atomic absorption spectrophotometry to determine the relationship between levels of these elements in mother's and infant's blood and maternal age, birth weight, and gestational age of the baby. The blood Zn level of mothers in the age group 24-28 yr was significantly higher than those of mothers in the age group of 18-23 yr (p<0.05). Similarly, mothers in the 24 to 28-yr group also had higher blood Fe level than mothers in the group 29-38 yr (p<0.05). The levels of Zn, Cu, and Fe were higher in the maternal blood and lower, but not significantly, in the cord blood of low-birth-weight babies than in those of normal-birth-weight babies. However, differences in the levels of Zn, Cu, and Fe between maternal and cord blood of the two birth-weight groups was statistically significant. There were no significant differences in the levels of the three elements in maternal or cord blood by the gestational age of the baby. A weak but significant correlation was found between the birth weight of the baby and the Fe level in the cord blood (r=0.26; p<0.05). Also, weak significant correlations were observed between gestational age of the baby and Fe (r=0.23; p<0.05) and Cu (r=0.31; p<0.05) levels in the cord blood. Although, there are many confounders of low birth weight and preterm deliveries, a diminished placental transfer of these essential elements could be one of the several etiological factors for low birth weight of newborns.

Neuropsychological studies on lead battery workers.

This study assessed the psychological status of 60 lead-acid battery workers occupationally exposed to low level lead and 30 referents in Lucknow. Digit spans and symbol, Bourdon-wiersma vigilance and Raven's Progressive matrices tests were administered. Significant impairments in concentration, attention, auditory and visual memory, psycho-motor speed, perceptual accuracy, and visual reasoning were observed in the workers compared to the referents. The deficits were not related to exposure duration since the magnitude of the impairments observed in workers with 1-y duration was the same as in those with more (up to 30 years) work duration. The blood lead of the battery workers was significantly elevated. There were functional deficits of the central nervous system in the lead-acid battery workers.