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1

The antiviral drug ribavirin reversibly affects the reproductive parameters in the male Wistar rat

100%
Narayana K., D'Souza U. J. A., Narayan P., Kumar G.
Folia Morphologica
|
2005
|
tom 64
|
nr 2
65-71
The present study was planned to evaluate the toxic effects of ribavirin on the reproductive parameters in the male Wistar rat. Rats (11–13 weeks old) were treated with 5 injections (i.p.) of 20, 100 or 200 mg/kg/day ribavirin at intervals of 24 h. The testes were processed for histopathological analysis on days 14, 35, 70 and 105 after the last exposure. The parameters studied were body weight, the weights of the testis, epididymis, seminal vesicle and prostate, seminiferous tubular diameter (STD), epithelial height (SE), epithelial sloughing, incidence of stage XIV tubules, sperm abnormality and total serum level of testosterone. Data were analysed by ANOVA and the Bonferroni post hoc test for significances between different groups. There was a decrease in body weight and organ weights, excluding those of the testis and epididymis, against control at higher dose-levels. Ribavirin induced the formation of vacuoles, gaps and sloughing of the seminiferous epithelium. The STD, SE and the incidences of stage XIV tubules decreased on days 14 and 35. Ribavirin also induced the formation of sperm with microcephaly and cephalocaudal junction defects, with or without fibrils jetting out. All these morphological defects recovered to control limit by day 105. The serum level of testosterone was decreased at all dose-levels and time points, although recovery had started by day 105. In conclusion, ribavirin is gonadotoxic in male rats but the effects are reversible after a period of 105 days. However, the endocrine-disrupting properties of ribavirin persist beyond this period.
2

Incidence, types and clinical implications of a non-metrical variant - mylohyoid bridging in human mandibles

100%
Narayana K., Narayan P., Ashwin K., Prabhu L. V.
Folia Morphologica
|
2007
|
tom 66
|
nr 1
Mylohyoid bridging (MB) is a non-metrical variant of the human mandible. The incidence and types of MB were investigated in 264 mandibles (edentulous 116, semi-dentulous 90 and dentulous 58). No mandible showed a complete type of MB, although 19 (7.2%) mandibles had a partial type. These were classified into two subtypes: distal partial (DP; Type I) and proximal partial (PP; Type II), depending on their location over the mylohyoid groove. The MB was present unilaterally in 7.76% of edentulous mandibles: right side 5.17% (3.45% PP type and 1.72% DP type) and left side 2.59% (1.72% PP type and 0.86% DP type). Of the semi-dentulous mandibles 3.33% had DP type of MB, 1.11% on the right side and 2.22% on the left side, and of the dentulous mandibles 1.72% had DP type of MB on the right side. A total of 13 mandibles out of 264 (4.92%) had unilateral MB. No dentulous mandible had bilateral MB, but 3.45% of edentulous and 2.22% of semi-dentulous mandibles did have. In total, 6 mandibles out of 264 bones (2.27%) had bilateral MB. Of the bilateral incidences 1.72% of edentulous mandibles had a DP-DP combination and the remaining 1.72% had a PP-DP combination. However, both instances of bilateral MB in semi-dentulous mandibles were of PP-DP combination. The incidence or types of MB showed no statistically significant differences between the groups or sides (p > 0.5; χ² test). In conclusion, the complete type of MB is a rare occurrence. The incidence increases with age, as edentulous mandibles had a higher incidence of MB than the other two groups. Clinically, MB may compress the mylohyoid neurovascular bundle, leading to neurological or vascular disorders.
3

The incidence of a superficial arterial pattern in the human upper extremities

100%
D'Costa S., Shenoy B. M., Narayana K.
Folia Morphologica
|
2004
|
tom 63
|
nr 4
The incidence of superficial arteries was studied in 68 (38 right and 30 left) upper extremities. One right limb of an adult male presented a superficial arterial pattern (2.63%, total 1.47%) resembling a superficial brachio-ulno-radial artery (SBUR). The median nerve crossed the superficial brachial artery (SBA) from the posterior to the medial side and again posterior to the same at the cubital fossa. The superficial brachial artery divided into superficial radial and superficial ulnar arteries, which coursed distally superficial to the muscles but deep to the deep fascia. The superficial radial artery passed deep to the extensor tendons of the thumb. The superficial ulnar artery gave only muscular branches in the forearm. The superficial radial artery gave origin to the radial recurrent artery and the common interosseous trunk. The latter gave origin to a palmar type of median artery, muscular branches, and an artery that divided into anterior and posterior ulnar recurrent arteries. It also gave origin to the anterior and posterior interosseous arteries. The latter provided the interosseous recurrent artery and a branch that coursed towards the olecranon process of the ulna. The knowledge of this variation is important since it may be compromised in surgical procedures of the upper limb.
4

The effect of carbamazepine on sperm counts in Wistar rats – reflecting upon its mitogenic potential 1

88%
Shetty A. J., Narayana K., Bairy K. L., Bhat P., D'Souza U.
Reproductive Biology
|
2007
|
tom 07
|
nr 2
5

The reproductive toxicity of the organophosphate pesticide O,O-dimethyl 0-4-nitrophenyl phosphorothioate [methyl parathion] in the male rat

76%
Prashanthi N., Narayana K., Nayanatara A., Chandra Kumar H. H., Bairy K. L., D'Souza U. J. A.
Folia Morphologica
|
2006
|
tom 65
|
nr 4
309-321
Methyl parathion (MP) is a pesticide widely used to protect crops but also illegally used in many countries for spraying homes and businesses to contain insects. The present study was planned to investigate the effects of MP on the male reproductive organs in the rat. Male Wistar rats (13–14 weeks old) were treated with MP and sacrificed as follows. Experiment 1: 0 (water vehicle), 1.75, 3.5 or 7 mg/kg (i.p.) for 5 days and sacrificed on day 14; experiment 2: 0, 0.5 or 1 mg/kg (i.p.) for 12 days and sacrificed on day 130; experiment 3: 0, 0.5 or 1 mg/kg (i.p.) for 12 days and sacrificed on day 77; experiment 4: 0, 0.75 or 1.5 mg/kg (i.p.) for 25 days and sacrificed on day 17; experiment 5: 0 or 3.5 mg/kg (p.o.) for 25 days and sacrificed on day 17 after the last exposure. The reproductive organs were removed, weighed and processed for histopathological analysis. Structural changes, for example the morphology of the epithelium and the lumina of the organs, were observed in all animals. Biochemical estimates of acid phosphatase (ACP), cholesterol, total protein, uric acid, and vitamin C were conducted in the epididymes. The weight of the epididymes increased in experiment 2 in a dose-dependent pattern (p < 0.01) and decreased in experiments 4 and 5 (p < 0.01). The weight of the ductus deferens decreased in experiment 3 at 1 mg/kg dose level (p < 0.001) and increased in experiment 5 (p < 0.05). The weight of the seminal vesicle decreased in experiment 3 at both 0.5 mg/kg and 1 mg/kg dose levels (p < 0.001), and increased in experiment 5 (p < 0.01). The weight of the prostate decreased in experiments 4 (in a dose-dependent pattern) and 5 (p < 0.001). ACP levels decreased in experiment 4 (p < 0.001) with a greater effect at 0.5 mg/kg than at 1 mg/kg. In experiment 5 (p < 0.01) cholesterol levels decreased to less than 50% of the control level for this experiment (p < 0.01) and protein levels also decreased (p < 0.01). Vitamin C levels decreased in a dose-dependent pattern in experiments 4 (p < 0.001) and 5 (p < 0.01). There were no effects on uric acid level. Sperm density was decreased in the epididymes of the rats treated and the epithelium of the epididymis and ductus deferens showed cellular necrosis, brush-border disruption and nuclear pyknosis. Nuclei were haloed, except in experiment 2 and the 0.5 mg/kg group of experiment 3. Methyl parathion did not induce significant changes in the structure of the seminal vesicle and prostate, except that epithelial folding was shorter than in the control. In conclusion, MP is a reproductive toxicant in the male rat and causes deterioration in the structural integrity of the reproductive organs and also the biochemical parameters in the epididymis.
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