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Biomedical subjects

H Adam

Publications and source records attributed to H Adam.

At least 55 records · Page 3Linked to original sources
PubMed1985

Distribution of aminergic neurons in the brain of the sterlet, Acipenser ruthenus (Chondrostei, Actinopterygii).

Aminergic nuclear areas were identified in the brain of Acipenser ruthenus using formaldehyde-induced fluorescence (FIF). One group of scattered, green fluorescent cerebrospinal-fluid (CSF)-contacting neurons is located rostral to the commissura anterior. A second very prominent field of green fluorescent neurons is situated within the recessus preopticus, the recessus preopticus organ (RPO). Caudal to the latter there is a group of green and yellow fluorescent CSF-contacting neurons, the anterior part of the paraventricular organ (PVO). Further caudally, towards the dorsorostral entrance to the recessus lateralis the latter group is continuous with the main part of the PVO, which consists of large green and yellow, fluorescent CSF-contacting neurons in a stratified arrangement. The PVO is caudally continuous with small, green fluorescent CSF-contacting neurons situated within the roof of the recessus lateralis. The nucleus recessus posterior is made up of green and yellow fluorescent CSF-contacting neurons, which cover not only the walls of the recessus posteriores, but also line the lateral, dorsal and caudal aspects of the caudal hypothalamus. Small groups of green and yellow fluorescent CSF-contacting neurons can be found also in other areas of the hypothalamic ventricular walls, especially dorsal to the PVO and within the hypothalamic floor. Three large groups of aminergic neurons are present within the brain stem: One, yellow-fluorescent raphe-system and two green fluorescent groups. The floor of the canalis centralis is lined by green fluorescent CSF-contacting neurons. There is a very low density of aminergic terminals within the brain of Acipenser. A prominent fibre tract connects the PVO and the nucleus recessus posterior.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Comparative scanning electron microscopy of the ventricular surface in four actinopterygian fishes: Acipenser ruthenus, Salmo gairdneri, Tinca tinca and Blennius sanquinolentus (Pisces).

The ventricular surface structure of the brains of actinopterygian fishes representing four distinct evolutionary levels was investigated by scanning electron microscopy (SEM). In the chondrostean Acipenser ruthenus ventricular spaces are wide and the ependymal surface is for the greater part densely covered with cilia; apart from macrophages supraependymal cells (SE) are very scarce. In the teleosts Salmo gairdneri, Tinca tinca and Blennius sanquinolentus the ventricles are slit-like, the densely ciliated areas decrease in size. The following regions carry a variety of supraependymal (SE) cells and fibres: the rostral recessus supraopticus, the hypothalamic walls, especially the infundibulum and the dorsal walls of the rhombencephalic ventricle. There is no tight correlation between areas devoid of cilia and the circumventricular organs in teleosts. The long evolutionary history, independent of other vertebrate lines has caused a series of peculiarities in the brain of actinopterygian fishes, including a peculiar ventricular topography. Observations indicate that the rich spectrum of SE cells found in teleosts reflects a parallel evolution rather than a common heredity of teleostean fishes and higher vertebrates.

Animals↗
PubMed1985

Fine structure and vascular supply of the median eminence (ME) in Acipenser ruthenus (Chondrostei).

The fine structure and vascular supply of the median eminence (ME) was studied in 57 specimens of Acipenser ruthenus (Chondrostei) by means of light microscopy (normal histology, horseradish-peroxidase (HRP), formaldehyde induced fluorescence (FIF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) as well as by SEM of vascular corrosion casts. Light microscopy revealed that the ME increases in thickness from caudal to rostral with capillaries invading the subependymal layers only at the rostral median eminence (rME). At the middle (mME) and caudal median eminence (cME) capillaries are limited to the ME outer surface. Short term HRP-application (systemically as well as intraventricularly) resulted in reaction product in the intercellular space throughout the ME after a survival time of 2 hours. The ME tanycytes were distinctly marked after 7 days survival. FIF revealed aminergic cerebrospinal fluid (CSF-) contacting neurons; also the apical part of tanycytes showed specific fluorescence. SEM of vascular corrosion casts showed that the arterial supply of the whole ME results from branches of the hypothalamic artery and/or from those arteries supplying the saccus vasculosus. The whole 2-dimensional primary capillary plexus of the ME drains via portal vessels into the adenohypophysis. As demonstrated by SEM, the ME ependymal surface is made up by oligociliated tanycytes, abundant crown cells and intraventricular protrusions of CSF-contacting neurons. Supraependymal cells are lacking, supraependymal fibres are very sparse. TEM revealed the ME tanycytes with long ciliary rootlets. Their basal processes split into numerous delicate branches forming many end-feet, which end at the basal lamina opposite the fenestrated capillaries of the primary plexus. Like tanycytes, also the crown cells possess branching processes which may contribute to the outer glial membrane. CSF-contacting neurons of the type I (with dense core vesicles ranging in diameter from 100-120 nm and of presumed aminergic nature) and type II (with dense core vesicles ranging in diameter from 160-180 nm and of presumed peptidergic nature) were found. Both types are most abundant in the cME. Small astrocytes reveal delicate processes which cover parts of the CSF-contacting neurons and of tanycytes. Another glial cell type is situated near the basal lamina and forms processes parallel the latter. There are few axo-somal and axo-axonal synapses pointing rather to a humoral regulation of the ME with signals from the ME blood vascular bed or from the CSF acting on CSF-contacting neurons.

Animals↗
PubMed1984

Effect of gossypol on bull spermatozoa in vitro.

Gossypol acetic acid in a concentration of 1,000 microgram/ml solvent is able to immobilize 1 ml of native bull semen (sperm concentration: 8.5 X 10(8)/ml; motility rate: 87.4%) within 30 min. After GAA treatment the spermatozoa show severe morphological damage on the membrane system, on the acrosomal complex and on the tubular complex of the end piece. The working mechanism of GAA can be assumed to be inactivation of enzyme activities or in direct reactions with plasma membrane material.

Animals↗
PubMed1983

The aminergic system in the brain of Blennius incognitus (Bath 1968) (Teleostei, Perciformes).

In the brain of Blennius incognitus the distribution of biogenic amines was investigated by means of formaldehyde-induced fluorescence (FIF). The telencephalon of Blennius is devoid of fluorescent perikarya. Fluorescent telencephalic fibers and terminals contain either dopamine (DA), noradrenaline (NA), or an indolamine. Two diencephalic nuclei display fluorescent perikarya, the nucleus recessus lateralis and the nucleus recessus posterioris; both nuclear regions contain DA. Only occasionally single green-fluorescent perikarya are found within the ependymal lining of the caudal portion of the recessus lateralis. Four fluorescent nuclei, two catecholamine-containing nuclei and one indolamine-containing nucleus, are present in the tegmentum of the midbrain and in the medulla oblongata. Three of these nuclei, N1 and N3, consist of large, green-fluorescent neurons, which apparently contain NA. N2, located medial to the nucleus isthmi, is formed by several clusters of small neurons, which show a yellow indolamine fluorescence. Caudal to the calamus scriptorius another green-fluorescent nucleus (N4) is visible.

Animals↗
PubMed1983

Ultrastructural analysis of rat testes after gossypol acetic acid (GAA) treatment.

The present investigations were carried out to show the histological and ultrastructural alterations in rat testes 10 weeks after gossypol acetic acid treatment (dose: 30 mg gossypol acetic acid/kg/day). the morphological findings in the interstitial compartment were compared with the data from studies carried out to investigate the testosterone biosynthesis in gossypol acetic acid treated rats. No morphological changes in the epididymal and vasal epithelia were found; however, the germinal epithelial cells showed vacuolisation, pycnosis, disconnections of junctions, cytolysis and exfoliation of germ cells from the epithelium. The Sertoli cells were affected, too. Gossypol acetic acid seemed to stimulate the physiological activity pathologically; cellular organelles as mitochondria, endoplasmic reticulum, lysosomal vacuoles, pigment granules and nuclei were either enlarged in size and number or malformed in shape. The cellular contact was often restricted to spots or completely disconnected. If gossypol acetic acid was administered for a longer period of time some Sertoli cells were found to be unable to withstand the toxic stimulus, and the cells became necrotic too. In contrast to the toxic process in the germinal and Sertoli cells the Leydig cell compartment did not show any changes in fine structure, and therefore testosterone biosynthesis is presumed to be intact.

Animals↗
PubMed1983

Influence of sample site on blood concentrations of ICI 35868.

Simultaneous blood samples from an artery, a peripheral vein and a central vein were analysed for ICI 35868 concentrations following an induction dose of 2.0 mg kg-1 administered i.v. over 60 s, to five patients before cardiac surgery. Up to 60 s after the end of the administration of the drug there were wide differences in drug concentration between the sampling sites. Thus, any attempt to correlate effect with blood concentration over this early period would be problematic. From 60 s there were no significant differences in drug concentration between the three sites. Thus, as long as the mixing period is allowed for, peripheral venous sampling provides an acceptable alternative to arterial puncture in studies to correlate drug effect and concentration and for pharmacokinetic investigations.

Adult↗
PubMed1983

Pharmacokinetics and tolerance of single intramuscular doses of cefotetan in normal Caucasian volunteers.

Cefotetan, a third-generation cephalosporin, is extremely well tolerated by healthy Caucasian volunteers when given by intramuscular injection. It gives rise to prolonged high plasma antibiotic concentrations. Lignocaine (0.5%), when used as a diluent, had no effect on the pharmacokinetic parameters of cefotetan. Two grams of cefotetan given as the disodium salt 12 hourly by the intramuscular route gives plasma levels that are likely to be clinically effective in the treatment of infections due to a very wide range of Gram-positive and Gram-negative aerobes and anaerobes. The validity of this prediction however can only be established by subsequent clinical trials.

Adolescent↗
PubMed1983

The endocrine status of gossypol - treated male rats.

Male adult Wistar rats were exposed daily or every other day to oral gossypol acetic acid (GAA) concentrations of 2.5-30 mg/kg for 10-20 weeks. Controls received the GAA-suspension medium or were left completely untreated. The serum concentrations of testosterone, LH and FSH as well as the weight of testis, epididymis, prostate, seminal vesicle, coagulating gland, and pituitary were determined. The accessory sex organs were prepared for light microscopy. Significant antifertility effect in these animals was achieved at GAA-dosage of 15 mg/kg and higher. GAA-administration neither altered the serum hormonal profiles nor the reproductive organ weights in comparison to the controls. Accordingly, light microscopical examination revealed no alterations in the histological picture of prostate, seminal vesicle and coagulating gland when compared with the controls. The results indicate that GAA does not interfere with the hypothalamic-pituitary-gonadal axis in male adult rats.

Animals↗
PubMed1983

Somatostatin-immunoreactive cells in the gastro-entero-pancreatic endocrine system of Xenopus laevis.

Somatostatin-like immunoreactivity has been demonstrated in cells of the gastro-entero-pancreatic endocrine system of Xenopus laevis (Amphibia) using peroxidase-anti-peroxidase immunohistochemistry. The identified cells of the gastro-intestinal tract correspond to the "Open-Paraneurons" of FUJITA (1974). Somatostatin-immunoreactive cells were found in the stomach (fundic and pyloric region), the duodenum and in the anterior ileum, but not in the colon. The dimensions of these 'Somatostatin-Open-Paraneurons' were measured: mean maximum height = 41.31 micron (S.D. = 10.87 micron), mean maximum breadth = 8.73 micron (S.D. = 2.31 micron). Frequency distributions of the maximum height and of the maximum breadth were processed by use of a computer. Somatostatin-immunoreactive cells in the pancreatic islets occupied about 15 to 25% of the total islets volume. These cells are "Closed-Paraneurons" (according to FUJITA 1974) with a mean diameter of 11.68 micron (S.D. = 2.61 micron).

Animals↗
PubMed1983

[Regression in the ovary of Myxine glutinosa L. (Cyclostomata). IV. Histochemical studies of atretic follicles].

Within the atretic follicles of Myxine glutinosa neither 3 beta-hydroxysteroiddehydrogenase, being in close relation to steroid production, nor cholesterol was found. The proofs of aryl sulphatase activity and acid phosphatase activity gave positive results in all cell types of the atretic follicle. A very strong reaction was observed in the granulosa cells and the migrating cells of the atretic follicle of the closed involutionary type.

3-Hydroxysteroid Dehydrogenases↗
PubMed1983

Development and differentiation of the brain ventricular system in tadpoles of Xenopus laeris (Daudin) (Amphibia, Anura).

The development and the differentiation of the ventricular system of the brain of tadpoles of the South African Clawed Toad, Xenopus laevis (Daudin), is studied by light microscopy (stages 45 to 66) and scanning and transmission electron microscopy (stages 50 to 66). Special interest is paid to the ependymal structures of the foramen of Monroe, the ventricles of the diencephalon, the mesencephalon, and the rhombencephalon, and to the ependymal of the central canal and the choroid plexus of the third and fourth ventricle. At early developmental stages the lower two thirds of the ventricles are dominated by blebs, cytoplasmatic protrusions of the ependymal cells. During the development they become reduced and replaced by cilia. The number of cilia and microvilli increases strongly towards the end of the metamorphosis. The surface structures demonstrated by scanning electron microscopy are discussed in respect to morphology and physiology.

Animals↗
PubMed1983

[Regression in the ovary of Myxine glutinosa L. (Cyclostomata) II. Electron microscope studies of atretic follicles].

In the atretic follicle of the open involutionary type an opening in the wall of the follicle is formed through which granulosa cells and yolk platelets are emitted. Migrating cells of the theca layer invade the follicular lumen and absorb phagocytotically residues of granulosa cells. On the other hand, atretic follicles of the closed involutionary type show yolk platelets which remain in the follicular lumen and are dissolved there. The granulated residue of the yolk platelets and the residue of the granulosa cells are absorbed phagocytotically by migrating cells. The follicular atresia of both degenerating types can be regarded as a process exclusively devoted to the purpose of resorbing atretic oocytes. No indications for the production of steroid hormones were found.

Animals↗
PubMed1983

[Crown cells in the diencephalon of Acipenser ruthenus (Acipenseridae, Chondrostei)].

Crown cells are considered to be typical for the Saccus vasculosus of gnathostome fishes. In Acipenser ruthenus these cells could be found on the entire floor of the diencephalon by SEM. There is one accumulation of crown cells in the frontal Recessus praeopticus, one caudal to the optic chiasma and one on the floor of the Recessus lateralis. The number of apical processes of the crown cells decreases significantly according to their distance from the Saccus vasculosus. In all basal gnathostome fishes examined until now, crown cells were found on the floor of the diencephalon outside the Saccus vasculosus.

Animals↗
PubMed1983

Scanning electron microscopical investigation of the larval development and the morphological differentiation of the paraventricular organ (PVO) of the South African clawed toad Xenopus laevis Daudin.

The development and the differentiation of the surface of the paraventricular organ (PVO) in tadpoles of the South African Clawed Toad Xenopus laevis Daudin from stages 46 to 66 and one adult animal was studied by means of light microscopy, scanning and transmission electron microscopy. At the light microscopical level, the PVO is visible from stage 46 on. From stage 48 on the organ is divided into two parts, a narrow rostral one and a more flattened and broad caudal one. From stage 58 on the rostral part of the PVO lies in the sulcus organi paraventricularis similar to the caudal part which lies in the sulcus lateralis infundibuli. The position of the PVO on both sides of the third ventricle is unchanged over all stages studied. The growth of the organ is finished at stage 65. The structure of the surface of the rostral and the caudal part of the organ differs up to the stage of 57. From stage 58 on the surfaces of the two parts of the PVO assimilate by developing a network of fibers which is orientated transversally. The different cell types of the PVO which can be seen at the level of transmission electron microscopy are fully developed at stage 57 but their position does not correspond to that of the adult animal. There is no difference between the right and left half of the organ in all groups studied.

Animals↗