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Biomedical subjects

S Haider

Publications and source records attributed to S Haider.

At least 73 records · Page 4Linked to original sources
PubMed1981

Histological and histochemical study of the caudal neurosecretory system of the freshwater teleost Ompok bimaculatus (Bloch) with a note on its response to hypophysectomy and osmotic stress.

The caudal neurosecretory system in well developed in Ompok bimaculatus. It extends from 8th to the last caudal vertebra. In the last vertebra the spinal cord forms a distinct, lobate and highly vascular ventral urophysis where the neurosecretory fibers have perivascular endings forming a neurohaemal organ. In the anterior segment near the 8th preterminal vertebra the Dahlgren cells are large and sparsely distributed. In the posterior segment close to the urophysis they are small and densely arranged. The neurosecretory material (NSM) has affinity for acid stains but reacts negatively to Gomori's stain or to a reagent demonstrating SS/SH group. The Dahlgren cells have high RNA content in the cytoplasm indicating active protein synthesis. Histological evidence suggests that the caudal neurosecretory system of this species did not respond to hypertonic osmotic stress. However, immersion in deionized water is accompanied by hypertrophy of Dahlgren cells and depletion of NSM from the caudal neurosecretory system. Hypophysectomy results in initial hypertrophy of the Dahlgren cells followed by atrophic changes and depletion of NSM. Ninety days after hypophysectomy this system gradually reverts to normal.

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PubMed1979

An in situ study of the hypothalamo-neurohypophysial complex of the freshwater teleost Ompok bimaculatus (Bloch) with a note on the tetrapodan features of its vascularization.

In Ompok bimaculatus the neurosecretory axons of both the pars magnocellularis and pars parvocellularis component of the nucleus preopticus contribute to the formation of the left and right main tracts. At rostral levels, one third of the tracts are loosely built forming a king of curtain, while they become more compact at caudal levels. The caudal two thirds of the main tracts give off several pairs of lateral tracts which join at the midline to form the paired median tracts. The median and the main tract jointly enter the pituitary as a common tract which, on entering the proximal pars distalis, separates into two and enters the pars intermedia. The hypothalamic and the hypophysial arteries take their origin from the internal carotid artery. The former contribute to the formation of the primary capillary plexus of the median eminence, whereas the latter enter the pituitary directly and ramify in the neuroadeno-interface. The primary capillary plexus is in close topographical contact with the neurosecretory axonal complex where the median and common tracts are formed. At this site at least some axons might have their endings on the capillary plexus. Thus, this region my be comparable in structure to the median eminence of the tetrapods. The neurons of the nucleus lateralis tuberis of O. bimaculatus are AF-positive. The infundibular cavity extends into the main neurohypophysial trunk and is lined by ependymal cells like the third ventricle.

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PubMed1979

Occurrence of oocytes in the liver of the percoid fish, Trichogaster fasciatus (Bloch and Schneider) and its probable significance.

Out of 500 Trichogaster fasciatus examined in one fish stage I and II oocytes were noticed in the liver and its blood sinuses. Apparently this is the first record of such occurrence. It is highly suggestive of the vascular migration of the germ cells enroute to the genital ridge. Possibly due to unknown reasons some might have been stuck up in the liver which is highly vascular.

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PubMed1978

Experimental and seasonal changes in the pituitary of the Teleost Heteropneustes fossilis (Bloch).

The pituitary of Heteropneustes fossilis is composed of a glandular adenohypophysis and a neurohypophysis (NH). The adenohypophysis is divided into three regions namely: rostral and proximal pars distalis (RPD and PPD) and pars intermedia (PI) consisting of seven different cell types. The RPD is made up of two cell types, the erythrosinophilic acidophils which form the major component of this region and H. Pb positive cells which border the NH. The latter exhibited hypertrophy during spawning and in radiothyroidectomised fishes. The erythrosinophils and H. Pb positive cells can be compared to the lactotrophs and corticotrophs described in the literature. The PPD is composed of three cell types: thyrotrophs, gonadotrophs and acidophils. The gonadotrophs and thyrotrophs readily take up the PAS, aldehyde fuchsin and anilin blue. The gnadotrophs show a marked numerical increase and hypertrophy in the breeding season, whereas they are small and comparatively few in nonbreeding season. In radiothyroidectomised fish the thyrotrophs show hypertrophy and degranulation and tendency to migrate into all the component parts, reaching upto the stalk region. In the control only few cells compared to thyrotrophs are seen in the NH and PI. The PI consists of H. Pb and PAS positive cells. They may be involved in the secretion of melanocyte stimulating hormone (MSH) and osmoregulation as suggested in the literature.

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PubMed1978

Micromorphology of the median eminence in the percoid fish, Trichogaster fasciatus (Bloch and Schneider).

The pituitary of Trichogaster fasciatus is devoid of a distinct stalk and is closely attached to the floor of the brain. The third ventricle is in wide communication with the anterior neurohypophysis adjacent to the pars distalis. The subterminal region of the hypothalamus and the anterior neurohypophysis forms the median eminence. Structurally this region can be compared to the median eminence of tetrapods as it is differentiated into ependymal, fibrous and reticular layers. A close morphological contact between the stainable neurosecretory and silver positive axons with the capillary plexus and accumulation of neurosecretory material around the capillary network suggest the presence of an incipient tetrapodan type of median eminence in this species.

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PubMed1977

Hypothalamo-hypophysial neurosecretory system of the teleost Trichogaster fasciatus (Bloch & Schneider) with a note on it's vascularization.

The hypothalamo-hypophysial neurosecretory (HN) complex of Trichogaster fasciatus is described with the help of in situ staining technique and tissue sections. The neurons of the nucleus preopticus (NPO) give rise to fine neurosecretory axons which form the left and right main tracts. The bulk of the tracts come laterally and enter the middle portion of the neurohypophysis. However, some of them spread out and penetrate the rostral neurohypophysis as well. Hypophysial artery contributes to the formation of primary capillary plexus (PCP) which extends from the subterminal region to the extremity of the anterior neurohypophysis. Structurally, the subterminal region and the anterior neurphoyophysis can be compared to the median eminence (ME) of tetrapods as it is differentiated into ependymal, fibrous and reticular layers. Also, these areas have aboundant neurosecretory and silver positive axons suggesting the possibility of direct transmission of neurohormones into the blood.

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PubMed1975

Antagonistic response of chlorpromazine and formalin in effecting quantitative changes in the neurosecretory material in the teleost Clarias batrachus (L.).

The hypothalamoneurohypophysial complex of Clarias batrachus maintains an appreciable quantity of neurosecretory material (NSM) under normal conditions. Stress caused by the injection of formalin depletes 70-90% of the stainable NSM from all the component parts of the neurosecretory system, namely the nucleus preopticus (NPO) the neurosecretory tract, and the neurohypophysis. Formalin apparently releases the NSM and stimulates the neurons of the NPO. Chlorpromazine (CPZ) treatment seems to cause quantitative increase of NSM throughout the neurosecretory complex. Simultaneous injection of CPZ and formalin showed that the formalin-induced depletion of NSM could be inhibited by CPZ.

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PubMed1975

Pituitary cytology of radiothyroidectomised teleost Heteropneustes fossilis (Bloch.).

The pituitary of Heteropneustes fossilis is divisible into rostral (RPD) and proximal (PPD) pars distalis, and pars intermedia (PI). Neurohypophysis extensively ramifies in the PI. The RPD is formed of acidophilic prolactin cells and lead hematoxylin (H. Pb) positive ACTH cells. The latter is arranged around the neurohypophysial extensions. The PPD is comprised of thyrotrophs (TSH) and gonadotrophs which are stainable with PAS, AF, and aniline blue. Acidophilic somatotrophs (STH) and chromophobes are scattered throughout the PPD. In the pars intermedia PAS positive and H. Pb positive cells are present. The latter is believed to secrete MSH whereas the function of the former is yet to be confirmed. In the partly and completely thyroidectomised H. fossilis the TSH cells exhibited marked hypertrophy. They are located in the middle of the PPD flanked by the gonadotrophs on either side. Hypertrophy of the ACTH cells were also evident. But the other cell types did not show any marked changes as compared to the controls.

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PubMed1975

Alcohol inhibition of formalin induced depletion of neurosecretory material in the teleost Clarias batrachus (L).

In the normal C. batrachus a fair amount of stainable neurosecretory material (NSM) is always present in all the component parts of the hypothalamo-neurohypophysial (HN) complex. When formalin was injected intraperitoneally 70 to 90% of the NSM was depleted from the HN complex. When ethyl alcohol was administered immediately after formalin treatment, the depletion of NSM was inhibited, and their staining intensity could be compared with those of untreated controls.

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