Browsing by Author "K.B. Singh"

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Anterior and posterior groups of portal vessels in the avian pituitary: incidence in forty nine species
(1975) K.B. Singh; C.J. Dominic
The hypophyseal portal vessels were studied in forty nine species of birds. The primary capillary plexus in the median eminence is single or divided into an anterior and a posterior plexus. Irrespective of whether the primary capillary plexus is single or divided, distinct, non interconnected anterior and posterior groups of portal vessels are present in all the species investigated. The anterior group of portal vessels originates in the anterior region of the median eminence and breaks up into capillaries in the cephalic lobe of the pars distalis; the posterior group of portal vessels originates in the posterior region of the median eminence and breaks up into capillaries in the caudal lobe of the pars distalis. This type of regional distribution of portal vessels appears to be of general occurrence in the avian pituitary. The median eminence in the species investigated shows an AF positive anterior region and an AF negative posterior region. The pars distalis is differentiated into histologically distinct cephalic and caudal lobes. The arrangement of the portal vessels into anterior and posterior groups provides morphological basis for the view that the functions of the cephalic lobe may be controlled by the anterior median eminence, whereas those of the caudal lobe may be controlled by the posterior median eminence. However, experimental data available to date do not suggest a physiological significance to the widespread incidence of the regional distribution of portal vessels in the avian pituitary.
Changes induced by morphine administration in the hypothalmic neurosecretory system of the spotted owlet, Athene brama Temminck
(1975) K.B. Singh; C.J. Dominic
[No abstract available]
Effect of ethanol on the hypertonic saline induced histological changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck
(1974) K.B. Singh; C.J. Dominic
[No abstract available]
Elemental and phytochemicals profile in ethno medicinal plants used for treating cardiovascular diseases by mizo-tribe of North Eastern India
(Chemical Publishing Co., 2019) J.P. Rajan; R.K. Mishra; K.B. Singh
Proton induced X-ray emission (PIXE) and gas chromatography-mass spectroscopy (GC-MS) were used to detect elements as well as phytochemicals in the Centella asiatica and Elsholtzia communis having possible roles for cardio-protections. Elements namely K, Cl, Ca, Fe, Mn, Zn and Cu were present in varying concentration with notable concentration of K, Cl and Fe. Phytochemicals such as stigmasterol, β-sitosterol, phytol and N-hexadeconic acid were detected in the C. asiatica while E. communis was found to contain β-carotene, β-sitosterol, phytol and N-hexadeconic acid. The study reveals that these two ethnomedicinal herbs are found to contain elements and phytochemical known for their cardio-protective roles. © 2019 Chemical Publishing Co.. All rights reserved.
Failure of chloral hydrate to block the hypertonic saline induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck
(1974) K.B. Singh; C.J. Dominic
Administration of chloral hydrate, 10 to 25 mg/animal/day, failed to block the appearance of the histological changes in the hypothalamic neurosecretory system (HNS) that normally follow daily administration of 1 ml of 3% NaCl solution. Since the histologic changes induced in the HNS by hypertonic saline are morphological manifestations of augmented secretion of antidiuretic hormone (ADH), the failure of chloral hydrate to block these changes in the HNS of the spotted owlet is suggestive of its failure to block ADH secretion. The failure of chloral hydrate to block the appearance of the hypertonic saline induced histological changes in the HNS contrasts with the ability of ethanol, reserpine and chlorpromazine to block the said changes in the HNS of the spotted owlet. The results suggest that in contrast to the situation prevailing in mammals, chloral hydrate does not exert an inhibitory influence on ADH secretion in birds.
Hydrocortisone inhibition of hypertonic saline-induced changes in hypothalamic neurosecretory system of the spotted owlet Athene brama Temminck
(1979) K.B. Singh; C.J. Dominic
[No abstract available]
Inhibition by chlorpromazine of the hypertonic saline induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck
(1974) K.B. Singh; C.J. Dominic
Administration of chlorpromazine (CPZ), 10 mg/animal/day, inhibited the appearance of the histological changes in the hypothalamic neurosecretory system (HNS) of the spotted owlet which normally follow injection of hypertonic saline, 1 ml/animal/day. The histological appearance of the HNS of the CPZ treated birds was comparable in all respects to that of the HNS of normal birds. Since the histological changes which are induced in the HNS by hypertonic saline administration are morphological indications of augmented secretion of the antidiuretic hormone (ADH), the inhibition, by CPZ, of these changes in the HNS of the spotted owlet, is suggestive of the inhibition of ADH secretion. Hence the results are interpreted as providing histological evidence in favour of an inhibitory effect of CPZ on ADH secretion. The results obtained in the spotted owlet are comparable to those obtained in mammals. The pathways involved in the CPZ induced inhibition of ADH secretion are briefly discussed.
Reserpine inhibition of hypertonic saline induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck
(1974) K.B. Singh; C.J. Dominic
The effects of reserpine on the histology of the HNS in the spotted owlet, Athene brama, which was treated with hypertonic saline, were investigated. Reserpine, 25-30 μg/animal/day, completely blocked the appearance of the histological changes in the HNS that normally follow daily treatment with 1 ml of 3% NaCl solution. The histological picture of the HNS of reserpine treated birds was identical with that of the HNS of normal birds, indicating the effectiveness of the drug in inhibiting the hypertonic saline induced histological changes in the HNS. Since the histological changes that are induced in the HNS by hypertonic saline are presumably indicative of increased secretion of ADH, the results are interpreted as providing histological evidence in favor of the concept that reserpine exerts an inhibitory effect on ADH secretion. It is suggested that the effect of reserpine on ADH secretion in birds is comparable to that reported in the case of mammals. The probable pathways involved in the reserpine induced inhibition of antidiuresis are discussed.
Sodium fluoride induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck
(1975) K.B. Singh; C.J. Dominic
Administration of 10 or 20 mg of sodium fluoride (NaF) induced depletion of neurosecretory material (NSM) from the neurons of the supraoptic (SON) and paraventricular (PVN) nuclei in spotted owlet (Athene brama Temminck). The residual NSM in the perikarya was arranged in cap like paranuclear positions. The NSM in the hypothalamo hypophysial tract, the zona externa of the anterior median eminence (ME) and in the neural lobe (NL) showed only a partial loss. The effects of NaF administration on the HNS of the spotted owlet are similar to those induced by such stimulators of ADH secretion as hypertonic saline, morphine and formalin. Hence the histological changes induced by NaF administration in the HNS of the spotted owlet are presumably indicative of increased neurosecretory activity resulting in the augmented secretion of ADH. It is suggested that NaF, like other stressful agents, is a stimulator of ADH secretion.
Stereometric observations on the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck, in total preparations
(1975) K.B. Singh; C.J. Dominic
The configuration of the HNS of the spotted owlet, Athene brama Temminck, was studied by employing the bulk staining technique. This enabled a three dimensional view of the HNS. The neurons of the SON are distributed into three divisions, namely, the preoptic, median and lateral. The PVN is U shaped; the distal portion of the arms of the U extends laterally to form the lateral division of the PVN, which remains in continuity with the lateral division of the SON. The periventricular division of the PVN joins ventrally the median division of the SON. Unlike in the passerine birds, in the spotted owlet the PVN is more prominently developed than the SON. Since the axonal pathways are not stained, the proximal portion of the hypothalamo hypophysial tract could not be demonstrated in bulk stained preparations. Hence it was not possible to trace with certainty the origin of the axonal terminations in the ME and in the NL. Anterior of the ME, the tract branches into two; one branch enters the zona externa to the ME and the other is continued into the NL. The ME is divisible into an AF positive anterior region and an AF negative posterior region. The NL is saccular and heavily loaded with the NSM. Studies on the HNS of the spotted owlet by the bulk staining technique reveal that the general configuration of the system is comparable to that of the HNS of birds studied previously.
Synthesis, characterization, dehydration and solid state conductance studies on chromium (III) oxaldihydrazide, azide/sulphate complexes
(1988) K.K. Narang; K.B. Singh
Chromium (III)-oxaldihydrazide-azide complexes of the type Cr(ODH(N3)y(|S04)3-y.6H2O>where x and y»l-3 and ODH = oxaldihydrazide,were synthesized. The complexes were characterized by elemental analysis, IR and electronic spectral and magnetic data, and studied for their weight loss (between 40-180°C) and solid state conductance. The complexes are insoluble in water and common polar and non-polar solvents, paramagnetic and semiconductors. Water molecules are partly coordinated and partly in the lattice. The sulphate and azide are ionic and ODH bonds to octahedral Cr(III) via -NH2groups. © 1988, Taylor & Francis Group, LLC. All rights reserved.
Synthesis, characterization, dehydration, solid state conductance and biological activity of chromium(III) benzoylhydrazin e azide/sulphate complexes
(1993) K.K. Narang; K.B. Singh; M.K. Singh; M.P. Goyle; K. Bhuvaneshwari; V. Singh
A series of chromium(IIl) benzoylhydrazine azide/sulphate complexes of the type Cr(BH)x(N3)y(SO4)3 y.6H20 where BH = benzoyl-hydrazine, C6H5CONHNH2and x, y = 1–3 have been prepared and characterized by elemental analyses, weight loss, IR and electronic spectra, solution and solid state conductance and magnetic susceptibility data. The complexes are paramagnetic and have octahedral stereochemistry with BH bonds to Cr(III) through >C=0 and-NH2 groups. N3 -and SO4 -- groups are ionically associated. Dehydration studies show stepwise elimination of water molecules. The molar conductance values of some of the complexes are low. Solid state conductance between 1.4 Χ 10-8to 18.16 Χ 10-8(ohm cm)-1varying with the number of N3 -groups and frequency, indicates a semiconducting nature of the complexes at room temperature. BH, NaN3, K2SO4Cr2(SO4)3.24 H20 and four of Cr(III) complexes were screened against Synechococcus cedrorum, a unicellular non-nitrogen fixing, mesophilic blue green alga, and have shown significant inhibition. © 1993, Taylor & Francis Group, LLC. All rights reserved.
synthesis, characterization, xrd, magnetic moments, electronic and ir spectra of chromium(III) malondihy dr azide azide/ sulphate complexes
(1993) K.K. Narang; K.B. Singh; M.K. Singh
Chromium(III) malondihydrazide azide/sulphate complexes of the type Cr(MDH) x(N3)ySO4)3_y.6H20, where x = y = 1–3 and MDH = malondihydrazide, CH2(C0NHNH2)2, have been synthesised and characterized by elemental analyses. All the complexes are insoluble in water and pol ar/non-polar common organic solvents. Electronic spectral and magnetic moment data indicate octahedral stereochemistry around chromium(III) in all complexes. MDH bonding occurs only through the two imino NH groups as indicated by the IR spectra. The azide and sulphate groups are ionically associated. The absence of sharp lines in the XRD patterns of two complexes indicate their micro crystalline character. © 1993, Taylor & Francis Group, LLC. All rights reserved.
Synthesis, electronic and IR spectral studies of some polymeric cobalt(II), nickel(II), zinc(II) and cadmium(II) azido complexes with hydrazine
(2009) Vinod P. Singh; K.B. Singh; K.K. Narang
A series of polymeric cobalt(II), nickel(II), zinc(II) and cadmium(II) azido complexes with hydrazine of the type [M(N2H4)(H 2O)(N3)Cl]n, [M(N2H 4)(N3)2]n and [M(N2H 4)2(N3)2]n have been prepared. These were characterized by elemental analyses, magnetic susceptibility measurements, electronic and IR spectra. The complexes are highly insoluble in polar and non polar solvents. All the complexes decompose with explosion at different temperatures between 100°C to 200°C. The magnetic moment and electronic spectral data for Co(II) and Ni(II) complexes suggest that the complexes have octahedral structure. The ligand-field parameters (10 Dq, B, Β, Β° and LFSE) have also been calculated for all Co(II) and Ni(II) complexes which indicate a significant covalent character of M-L bonds. The IR spectra of the complexes show that the azide group and hydrazine molecule both act as bidentate bridging ligands in [M(N2H 4)(H2O)(N3)Cl]n and [M(N 2H4)(N3)2]n type complexes but the azide group is terminally bonded to metal in all [M(N 2H4)2(N3)2]n type complexes.