Tracheobronchial tree and pulmonary arteries: MR imaging using electronic axial rotation

Standard coronal magnetic resonance (MR) imaging cannot depict long segments of the tracheobronchial tree and left pulmonary artery owing to the normal thoracic kyphosis and posteriorly angled course of these structures. By the use of electronic axial rotation (EAR), however, MR is capable of imaging any plane. We used EAR in 25 patients undergoing MR examinations of the thorax. This technique allowed superior definition of the longitudinal axis of the tracheobronchial tree and left pulmonary artery. The right pulmonary artery was satisfactorily imaged by the standard coronal plane.     

Study of enzyme polymorphism and haemoglobin patterns amongst sixteen tribal populations of central India (Orissa,Madhya Pradesh,and Maharashtra)

Summary A survey was conducted to study the genetic differentiation among 16 tribal groups of Orissa, Madhya Pradesh, and Maharashtra belonging to different ethnic and linguistic affiliations. Sixteen hundred and fifteen blood samples from both sexes were tested for 5 red cell enzyme systems: ACP, ESD, PGD, GLO, LDH, and Hb pattern. Three hundred and nineteen male individuals were tested for G-6-PD enzyme deficiency. The distribution of the enzyme markers and Hb show a range of variation which are more or less within the Indian range. Case of homozygous HbSS were detected in all the tribes except 3 tribes in Orissa. Two cases of LDH Cal-1 homozygote were found in two Dravidian language speaking Orissa tribes. The X²-values for testing the homogeneity of gene frequencies indicate a non-significant heterogeneity for all alleles in the individual system. Within population diversity seems to be larger than between population diversity. The degree of over all genetic differentiation as measured by G_ST value is 0.0154±0.0071.     

Central nervous system receptors involved in mediating the inhibitory action of neuropeptide Y on luteinizing hormone secretion in the male rhesus monkey (Macaca mulatta)

An earlier finding that gonadotropin-releasing hormone (GnRH) secretion may be triggered prematurely in the juvenile male monkey by central administration of 1229U91, a Y1 receptor antagonist, contributed to our current hypothesis that neuropeptide Y (NPY) is a major component of the brake that holds pulsatile GnRH release in check during prepubertal development in primates. However, 1229U91 is also a Y4 receptor agonist, and the present study was conducted to further examine the role of the Y1 receptor in mediating the putative inhibitory action of NPY on GnRH release. Agonadal juvenile and postpubertal male monkeys were implanted with i.v. and i.c.v. cannulae to gain continuous access to the venous and cerebroventricular circulations without sedation. Luteinizing hormone (LH) secretion was measured to provide an indirect index of GnRH release. The specific Y1 antagonists, VD-11 (476 microg; n = 4) and isopropyl 3-chloro-5-[1-((6-[2-(5-ethyl-4-methyl-1,3-thiazol-2-yl)ethyl]-4-morpholin-4-ylpyridin-2-yl)amino)ethyl]phenylcarbamate (Compound A, 300 microg; n = 4), did not mimic the stimulatory action of 1229U91 on GnRH secretion in the juvenile male monkey. Additionally, neither NPY (200 microg; n = 2), a general Y receptor agonist, nor rPP (100 microg; n = 4), a Y4 agonist, mimicked the action of 1229U91 in stimulating GnRH release. Moreover, previous exposure of the hypothalamus of juvenile monkeys (n = 5) to NPY (660 microg) failed to block 1229U91-induced (200 microg) GnRH release. However, the action of NPY (364 microg) in inhibiting GnRH release postpubertally was attenuated by 1229U91 (300 microg). We conclude that, although the action of exogenous NPY to suppress GnRH release from the postpubertal hypothalamus appears to be mediated, at least in part, by the Y1 receptor, the existence of a Y1 receptor pathway inhibitory to GnRH release in the prepubertal hypothalamus remains to be substantiated.     

Rearrangement of p53 gene with overexpressed p53 protein in primary cervical cancer

The frequency of p53 mutations is low and there is evidence of p53 protein overexpression even without p53 mutations in cervical cancers. This suggests that alternative mechanisms other than p53 mutation could be responsible for tumourigenesis of the uterine cervix. Therefore, an attempt has been made in the present investigation to analyze mutation and rearrangement of p53 gene in primary cervical cancers. The results indicated absence of mutation and presence of rearrangement in about 35% of cervical cancer patients. However, p53 overexpression in 50% of patients was demonstrated by immunohistochemistry and Western blot analysis. Further, rearrangement of p53 has been correlated with p53 mRNA and p53 protein status. The results indicated presence of overexpressed p53 protein in the samples with rearranged p53 gene. Thus, it is presumed that rearrangement of p53 might lead to production of defective p53 protein by affecting the level of p53 protein and this might have a role in the process of tumourigenesis. This study reports for the first time rearrangement of p53 in cervical cancers.     

Effect of choline and mineral fibres (chrysotile asbestos) on guinea-pigs

Both short-term and long-term, low and high doses of parenterally administered choline produce pathological lesions in lungs and lymph-nodes of rats and guinea-pigs. Male guinea-pigs given choline by intraperitoneal injection, 40 doses of 50 mg of choline chloride, 5 days per week for 8 weeks, developed lung lesions consisting of peripheral nodules of small cells, neoplastic bronchiolar epithelium, carcinomatous lesions and changes in the pleural surface by the end of the experiment (680 days). In a second group, a single intraperitoneal injection of 15 mg of chrysotile asbestos given after 210 days of choline administration resulted in the early onset of pulmonary lesions at 570 days but there was, in addition, evidence of enhancement of cancerous lesions both in lung and in lymph-nodes at 570 days and 680 days as compared with choline alone. It is clear from the present experiment that the parenteral administration of carcinogenic mineral fibres (chrysotile asbestos) and availability of excess choline act synergistically in producing cancerous lesions in lungs and other organs.     

Effects of antioxidants on quercetin-induced nuclear DNA damage and lipid peroxidation

The effects of catalase, superoxide dismutase, mannitol, glutathione, and diallyl sulfide on quercetin-induced DNA damage and lipid peroxidation were investigated in a model system of isolated rat-liver nuclei under aerobic conditions and in the presence of equimolar iron or copper. Mannitol produced a small but significant inhibition of the concurrent nuclear DNA damage and lipid peroxidation induced by quercetin in the presence of iron or copper. Catalase significantly decreased quercetin-induced nuclear DNA damage only in the presence of iron and had no significant effect on lipid peroxidation. Superoxide dismutase showed no significant effect on nuclear DNA damage, but stimulated the quercetin-induced lipid peroxidation only in the presence of copper. Glutathione significantly inhibited the nuclear lipid peroxidation but enhanced the DNA damage. Diallyl sulfide significantly enhanced the nuclear DNA damage but stimulated the lipid peroxidation only in the presence of iron. These results suggest that the reactive oxygen species, especially the hydroxyl radicals, are responsible for the concurrent lipid peroxidation and DNA damage induced by quercetin in the presence of iron or copper in isolated rat-liver nuclei.