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Biomedical subjects

R Hassler

Publications and source records attributed to R Hassler.

At least 55 records · Page 3Linked to original sources
PubMed1978

The normal seminal vesiculogram.

Vasoseminal vesiculography was performed on 69 asymptomatic men. Considerable variability in the appearance of the normal adult seminal tract was seen. On the left, the normal seminal vesicle averaged 5.6 cm long, 2.0 cm wide, and 0.6 cm in luminal diameter; on the right, it averaged 5.0 cm long, 2.0 cm wide, and 0.6 cm in luminal diameter. The normal ejaculatory duct averaged 16.0 mm long and 1.5 mm wide on the left and the same on the right. Criteria for normality are presented and the radiographic techniques reviewed.

Adult↗
PubMed1978

[Demonstration of intrastriatal types of synapses and axon-collaterals by experimental isolation of fundus striati from all extrastriatal connections (author's transl)].

After columnar isolation of the cat's fundus striati with a survival time of 2 days or 2 or 4 weeks all axospinous boutons (type I, III And iv) and most axo-dendritic (or axo-somatic) boutons (type II, VI and VII) undergo dark degeneration. All specimens of axo-somatic (or axodendritic) type IX bouton (containing large, round vesicles in a clear axoplasm) and most specimens of type V bouton (with pleomorphic and some dense core vesicles) are unaltered. Many type VIII boutons (dindritic terminals containing scattered, small, sphrical vesicles suspended between the filaments of many microtubules in clear dendroplasm) are almost preserved, in the fundus more than in the caudate nucleus. After 2 or 4 weeks, some perikarya and many dendrites have undergone an electron-dense retrograde degeneration resulting from interuption of the efferent axons of the large striatal cells. The type IX synapses are interpreted as intrinsic between the small spiny and the large efferent striatal neurons; the type V as intrastriatal axon-collaterals of the large efferent neurons and the type VIII as dendritic terminals of intrastriatal Golgi type II nerve cells (possibly dwarf cells).

Animals↗
PubMed1977

Electron microscopic study of terminal degeneration in the anterodorsal thalamic nucleus of the cat.

The ultrastructure and synaptic organization of the anterodorsal nucleus (AD) of the thalamus were investigated under normal and experimental conditions. The large glomeruli are composed of an extensive central dendrite, probably arising from a projecting neuron, and of various terminal boutons. Besides the typical small bouton (RS) filled with round vesicles, two specializations of the large bouton (RL) containing round vesicles are found. The larger one (RL1) is characterized by a looser arrangement of synaptic vesicles and many mitochondria; it undergoes dark degeneration following unilateral lesions of the mamillary body in both AD. The intermediate type (RL2) is distinguished by a denser arrangement of vesicles; it undergoes dark degeneration following lesions of the midline nuclei of the thalamus. The two types of terminal boutons (F1 and F2) which contain flattened or pleomorphic vesicles do not degenerate following lesions of the mamillary body and midline nuclei; they belong to Golgi type II interneurons.

Animals↗
PubMed1977

Degeneration of two of nine types of synapses in the putamen after center median coagulation in the cat.

The cat putamen contains the identical nine types of synapses and the same proportion of axo-dendritic (or axo-somatic) synapses as described for the fundus striati. However, type III (cortico-striatal) (31:16%) and type V Caxon-callateral) (13:1%) occur much more frequently and type I (nigro-striatal) much less frequently (14:34%) in the putamen than in the fundus striati. Of the axo-spinous synapses only type IV, with densely arranged small round vesicles and interrrupted, asymmetric contact, shows a dark degeneration after center median lesions, mainly in the parvocellular part. Of the six axo-dendritic (or axo-somatic) synapses, only type VII, with densely packed small round vesicles and asymmmetric contact, is degenerated after the same lesion in the center median nucleus. However, after such lesions type VII synapses are much more frequently degenerated in the putamen than those of type IV.

Animals↗
PubMed1976

[Interaction between the systems involved in fast pain perception and in slow, persistent pain (author's transl)].

A single pinprick triggers both a pang, the "1st pain" and after a pause of 0.5 s, a spreading burning feeling, the "2nd pain". The 2nd pain is delayed because it is conducted by unmyelinated C-fibers at a rate of less than 1 m/s, 20 times slower than conduction of the 1st pain. In the spino-thalamic tract the myelinated fibers of the 1st pain conduct much faster than those of the 2nd pain, and terminate in the parvocellular ventroposterior (VP) thalamic nucleus, which projects to area 3b in the postcentral gyrus. The slow C-fibers of the 2nd pain terminate in cortex-independent thalamic nuclei like limitans, which project to the outer segment of the pallidum. This subcortical pain pathway is disinhibited after destruction of the cortical pathway of the 1st pain, so that the patients suffer from spontaneous agonizing pain feeling (thalamic pain). Unbearable pain in cases of thalamic softening, in anaesthesia dolorosa and in phantom pain can be relieved by stereotactic coagulation of the thalamic nuclei involved in the 2nd pain. Normally they are inhibited by the cortical pathway of the 1st pain.

Analgesia↗
PubMed1976

Degenerated boutons in the fundus striati (nucleus accumbens septi) after lesion of the parafascicular nucleus in the cat.

An attempt has been made to reveal which of the nine different types of synapses in the fundus striati, discriminated in a previous study, degenerate following experimental lesions in the parafasciculo-center median complex of the cat. Two types of synaptic contacts were found to be degenerated two days after the lesion was performed: (1) the axo-spinous type IV, characterized by densely-packed, small, round vesicles and a strong asymmetric thickening, and (2) the axo-dendritic or axo-somatic type VII, again characterized by small, round vesicles in a dense accumulation and an asymmetric thickening. After two days of survival the original characteristics of the boutons could still be recognized in both types of synapses. A positive correlation exists between the location and extent of the coagulation foci in the parafascicular nucleus and the appearance of degenerated boutons in the fundus striati. Therefore, the conclusion that the parafasciculofundus neurons terminate as type IV or type VII boutons is entirely justified. Additionally, the role of the special types of boutons in the synaptic organization of the fundus striati has been discussed.

Animals↗
PubMed1976

The discrimination of nine different types of synaptic boutons in the fundus striati (Nucleus accumbens septi).

An attempt has been made to discriminate additional types of synapses than have been previously described in the nucleus accumbens septi of the cat, which can, according to Brockhaus (1942), justifiably be termed the fundus striati due to the fact that it possesses all of the morphological and some of the neurochemical features of the striatum. This was undertaken in order to correlate at least one type of synapse with each different afferent pathway. Nine distinct types of synapses could be differentiated electron microscopically: Type I: axo-spinous synapses with sparse, small, round vesicles which seemed to be the nigro-striatal endings (35%). Type II: axo-somatic or axo-dendritic en passant synapses containing small, round vesicles (3%). Type III: axo-spinous synapses filled with densely-packed, small, round vesicles displaying strong postsynaptic thickenings which seem to be cortico-striatal (17%). Type IV: large axo-spinous synapses with densely-arranged, small, round vesicles contacting larger spines branching off a pedicle (9%). Type V: axo-somatic or axo-dendritic synapses containing large pleomorphic vesicles, probably axon collaterals (1%). Type VI: axo-somatic or axo-dendritic synapses with elongated small vesicles (20 X 45 nm) (3%). Type VII: large axo-somatic or axo-dendritic synapses filled by densely-packed, small, round vesicles (11%). Type VIII: large axo-somatic or axo-dendritic synapses containing loosely-arranged, small, round vesicles (8%). Type IX: axo-somatic or axo-dendritic synapses containing large, round vesicles in a translucent axoplasm (13%).

Animals↗
PubMed1976

The nigrostriatal projection in the cat. Part 1. Silver impregnation study.

The course and destination of the degenerating nigrostriatal fibers were studied by selective silver impregnation methods in 37 cats with unilateral lesions in the substantia nigra. The nigrostriatal fibers ascend along the dorsomedial border of the substantia nigra to the prerubral area; they proceed for a short distance through the lateral hypothalamus, enter the medial part of the internal capsule and run in a dorsorostral direction to reach the head of the caudate nucleus and the rostral portion of the putamen. A smaller number of degenerating fibers obliquely cross the peduncular part of the internal capsule and traverse the entopeduncular nucleus and the pallidum to terminate in the central and caudal portions of the putamen. Some features of the topical distribution of the nigrostriatal tract are described. Apparently, the more anterior part of the pars compacta sends axons primarily to the head of the caudate nucleus and to the most rostral putamen. The most medially situated nigral neurons project to the fundus striati. The posteromedial cell groups of the pars compacta innervate primarily the central putamen and the caudal part of the caudate nucleus. The projection of the lateral cell group of the posterior zona compacta to the caudal putamen is sparser than from the other nigral groups, suggesting that a part of them has another destination, possibly lower in the neuraxis. The contribution of the pars of reticulata to the nigrostriatal connections seems to be modest, according to the small number of neurons; they project to the lateral caudate and putamen. Thus, the ascending nigrostriatal fibers mirror the distribution of the descending striatonigral fibers. No convincing evidence for the existence of a nigroentopeduncular and nigropallidal projection was found.

Animals↗
PubMed1976

Regional distribution of choline acetyltransferase and acetylcholinesterase activity in baboon brain.

(1) The activities of choline acetyltransferase (ChAc) (EC 2.3.1.6) and acetylcholinesterase (AChE) (EC 3.1.1.7) were determined in about one hundred regions and subregions of baboon brain. The activities and distributions of these enzymes were in comparable to those found previously in the brains of other species. (2) ChAc activity was highest in the interpeduncular nucleus, where it was about twice that in the putamen, the region previously thought to be the richest in this enzyme. The caudate nucleus, the substantia perforata, the nucleus basalis, the central part of the amygdala and the oculomotor nucleus also had high activities. The activities in the cerebral and cerebellar cortex were less than one twentieth of that in the interpeduncular nucleus. (3) The distribution of AChE activity was not entirely in parallel with that of ChAc.

Acetylcholinesterase↗
PubMed1975

Intention myoclonus of multiple sclerosis, its patho-anatomical basis and its stereotactic relief.

The typical multiple sclerosis case considered here is especially informative from both the standpoint of its clinical course and on the basis of the autopsy findings. The foci responsible for the severe bilateral intention myoclonus of the trunk and limbs are the nerve cell losses in both red nuclei due to extensive and almost complete demyelination. Thereby the triangle of Mollaret between the red nucleus, inferior olives and dentate nucleus is involved as the patho-physiological circuit responsible for myoclonus. Stereotactic coagulation of dentato-thalamic fibres resulted in complete relief of intention myoclonus. With regard to the triggering of fresh demyelinating foci by stereotactic interventions, our point of view is as follows: Although a stereotactic operation introduces the possibility of triggering new demyelinating foci in less than 10% of the cases, such a possibility does not represent an absolute contra-indication to the stereotactic treatment of action myoclonus in multiple sclerosis, if the patient is informed accordingly.

Adult↗
PubMed1975

Experimental kuru in the spider monkey. Histopathological and ultrastructural studies of the brain during early stages of incubation.

The brains of 10 spider monkeys inoculated intracerebrally with brain suspension from kuru patients have been studied histologically and ultrastructurally. The animals were killed by perfusion of fixative from four to forty-one weeks after inoculation, when healthy and free of neurological signs. Definite histopathological changes had occurred as early as four weeks after inoculation, when moderate numbers of bi-nucleated neurons were found within the limbic cortex, striatum, the hypothalamus and amongst the Purkinje cells of the cerebellum. At later stages of incubation a moderate loss of neurons in the cerebral and cerebellar cortex and a mild to moderate proliferation of fibrous astrocytes here and also in the hypothalamus were the most striking features. None of our cases showed either status spongiosus or the generalized astrocytic proliferation and hypertrophy, characteristic of fully developed experimental kuru, in any region of the brain. The principal ultrastructural abnormalities consisted of the formation of membrane-bound intracytoplasmic vacuoles, predominantly within dendrites, and of concentric laminar arrays derived from the endoplasmic reticulum. The former were seen in all regions of the brain examined and at all stages of incubation. Concentric laminar arrays were confined to the cerebellar nodulus, where they were most numerous in dendrites and neuronal perikarya four weeks after inoculation. Both changes are interpreted as an indication that the kuru agent acts upon the plasma membrane from an early stage onwards and, by stimulating its growth, leads to the formation of complex, membrane-bounded vacuoles and to hyperplasia of the endoplasmic reticulum. The formation of vacuoles is further regarded as the first sign of status spongiosus on an ultrastructural level. Attention is drawn to the great similarities between the changes observed in the present material and those described in the brains of patients dying from kuru and of primates with fully developed experimental kuru. The significance of the relatively rapid spread of the kuru agent throughout the brain is discussed in relation to the concept of "slow virus" diseases.

Animals↗
PubMed1975

Activity of L-glutamic acid decarboxylase in different regions of baboon brain.

1. The activity of glutamic acid decarboxylase (GAD), the enzyme synthesizing gamma-aminobutyric acid (GABA), was determined in over one hundred areas and sub-areas of baboon brain. Remarkably higher enzyme activities were found in the substantia nigra, the pallidum, the colliculi and the certain regions of the hypothalamus. These findings agreed with earlier report on fewer numbers of regions in the brains of lower mammals. 2. By careful dissections and determinations, several specified nuclei of extremely small size were also studied and it was found that the bed nucleus of the stria terminalis had enzyme activity equivalent to that in the substantia nigra. Considerable activity was also found in the coordination nuclei in the midbrain, the nucleus basalis and some other restricted regions. 3. The significance of the differences in GAD activities found in the various regions of the brain is discussed.

Animals↗
PubMed1975

Pathologic-anatomical findings and cerebral localization in stereotactic treatment of extrapyramidal motor disturbances in multiple sclerosis.

Two postmortem case of multiple sclerosis treated by sterotactic operations for the intention shaking of limbs, trunk, and head, and for the action myoclonus are analyzed to determine the location of the substrate of myoclonic and ballistic movements, the location of the coagulations for relief of these movements, and whether fresh demyelinating foci are elicited by intracerebral interventions. In the first case of a clinically typical multiple sclerosis, the foci responsible for the severe action myoclonus and intention ataxia of the trunk are demyelinations in the right and left red nucleus resulting in nerve cell damage and loss and an almost complete destruction of myelinated fibers. The restricted foci in the white matter of the cerebellum which do not involve the cerebellar nuclei are not extensive enough or old enough to be the cause of the action myoclonus but may, perhaps, sustain the pathogenesis. - In the second case of cerebral palsy and combined multiple sclerosis (detected post mortem), the combination of the severe damage of putamen and caudate nucleus by status marmoratus and the extensive nerve cell and fiber damage due to demyelinating foci in the substantia nigra are probably the substrate of the jactitation and intention myoclonus of the left limbs. The stereotactic coagulation of the dentatothalamic and pallidothalamic fibers in the base of V. o.p. and V.o.a. at the point where they pass through the zona incerta (location confirmed post mortem) resulted in a nearly complete relief of hyperkinetic movements. In the first case, fresh demyelinating foci are present in both hemispheres with stereotactic interventions; these foci are located, amongother places, around the coagulation and the electrode track. In the second case, post mortem serial brain sections demonstrate that stereotactic operations even in subacute multiple sclerosis can be carried out without eliciting any exacerbation of demyelination foci. Therefore, the danger exists that stereotactic intervention in cases of multiple sclerosis may precipitate fresh demyelinating foci. As our clinical experience [Riechert and Richter, 1972a, b] indicates, however, this occurred in markedly less than 10% of the cases.

Adult↗