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Biomedical subjects

C J Dominic

Publications and source records attributed to C J Dominic.

At least 73 records · Page 4Linked to original sources
PubMed1978

Sterilization of a non-scrotal mammal (Suncus murinus L.) by intratesticular injection of cadmium chloride.

The testis of the musk shrew is resistant to subcutaneous administration of cadmium chloride. In contrast, a single intratesticular injection of cadmium chloride (0.01 to 0.03 mM/kg body weight) caused total destruction of germinal epithelium; Leydig cells, however, regenerated after an initial phase of atrophy. Unilateal injection of the drug induced degenerative changes in the injected testis only; the contralateral testis appeared normal macroscopically and histologically. The factors responsible for the differential response of the testes of this non-scrotal mammal to the two routes of administration of cadmium chloride are discussed.

Animals↗
PubMed1977

Morphology of the accessory reproductive glands of some male Indian chiropterans.

The accessory glands of seven species of male chiropterans are described. The unpaired prostate and paired Cowper's glands occur in all the species. The seminal vesicles are present only in Cynopterus and Taphozous. The ampullary glands occur in all the species except Cynopterus sphinx. The presence of solid rounded bodies is a characteristic feature of the seminal vesicles of Cynopterus sphinx. The urethral gland is present in all the species except Taphozous and Rhinopoma; utriculus prostaticus was not seen in any of the species investigated. The study reveals that the male accessory glands show great diversity and remarkable differences are seen even between closely related species.

Animals↗
PubMed1975

Stereometric observations on the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck, in total preparations.

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.

Animals↗
PubMed1975

Changes induced by formalin in the hypothalamic neurosecretory system of the spotted owlet, Athene brama temminck.

Histological changes induced in the HNS of the spotted owlet, Athene brama Temminck, by injection of 1 ml 5 or 10% formalin are described. No difference could be detected in the response of the HNS to 5 or 10% formalin administration. In the HNS of birds killed within 5 min of formalin administration, there was only partial depletion of NSM from the neurons, the tract and the NL; the quantity of NSM in the AME remained more or less unchanged. In animals killed 10-90 min after formalin injection, the depletion of NSM from the neurons, the tract and the NL was more complete. The neurons of the preoptic division of the SON exhibited the maximum response; these neurons were also moderately hypertrophied. The NL also was hypertrophied in some animals; the NSM in the AME registered only a partial loss. The interval between formalin administration and killing did not influence the degree of changes in the HNS. The depletion of NSM was no greater at 90 min following formalin injection than at 10 min. Since it is well established that formalin stress causes augmented secretion of ADH and that there is a close functional relationship existing between ADH and NSM, the depletion of NSM noticed in the HNS of the spotted owlet following formalin administration is interpreted as indicating augmented secretion of ADH. Hence it seems that the response of the HNS of birds to formalin stress are comparable to those of the HNS of mammals. The results thus provide histological evidence in favour of the concept that stressful stimuli cause increased secretion of ADH.

Animals↗
PubMed1975

Sodium fluoride-induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck.

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 aranged in caplike 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 lossmthe 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.

Animals↗
PubMed1975

Anterior and posterior groups of portal vessels in the avian pituitary: incidence in forty nine species.

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.

Animals↗