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PubMed1987

Cerebral activating properties of indeloxazine hydrochloride.

The cerebral-activating properties of indeloxazine hydrochloride [(+/-)-2-[(inden-7-yloxy) methyl]morpholine hydrochloride, YM-08054] were examined in comparison with those of calcium hopantenate (a cerebral metabolic enhancer), dihydroergotoxine (a cerebral vasodilator), viloxazine and amitriptyline (antidepressants). Indeloxazine enhanced the acquisition of learned behavior (passive avoidance, active avoidance and maze learning) and desynchronized the spontaneous EEG in rats. Amnesia in scopolamine-treated rats, disturbances of consciousness in concussed mice and synchronized EEG in rabbits with lesions of the internal capsule were improved by the administration of indeloxazine. Calcium hopantenate and dihydroergotoxine also showed cerebral-activating properties in the majority of behavioral and electroencephalographic paradigms; however neither improved scopolamine-induced amnesia and calcium hopantenate had no effects on learning. Neither viloxazine nor amitriptyline enhanced the acquisition of learned behavior. The results indicate that indeloxazine possesses activating effects on cerebral functions, including learning and the EEG, and that the pharmacological profile of indeloxazine is wider than those of dihydroergotoxine and calcium hopantenate in cerebral-activating activity.

Amnesia↗
PubMed1996

Inverse relationship between sensation of effort and muscular force during recovery from pure motor hemiplegia: a single-case study.

A 39-year-old patient with a right pure motor hemiplegia, who complained of a striking sensation of effort when he performed a movement, was regularly examined during 4 months. The effort sensation and the force recovery have been measured during the execution of upper limb movements: shoulder antepulsion up to horizontal, supined elbow flexion up to horizontal and full hand digital grip. The subject was asked to realize a movement with the paretic arm and to concentrate on the felt effort; then he had to perform the same movement against a resistance with the healthy arm, until the perceived heaviness matched the effort sensation felt on the other side. Recovery of force and evolution of effort sensation did not follow linear trends over time. The curves displayed significant steps and plateaus, which were mainly observed for the proximal movements. The steps tended to be clustered within a few days, consistent with crucial periods in the restoration process. Within these, significant reduction of the effort sensation and increase of the force were together observed. These critical moments of the motor recovery could be analyzed as the result of an improvement of the neural traffic in the internal capsule and an activation of specific structures involved in the representation of the force and effort.

Adult↗
PubMed1977

Neural pathway mediating somatic evoked responses in the caudate nucleus of cats.

The course of somatic afferents to caudate nucleus (CN) was investigated. In curaized cats discrete lesions in intralaminar nuclei, n. centralis medialis (NCM) affect evoked response (ER) in CN to radial nerve stimulation. NCM lesions totally abolish these somatic responses, while after subthalamic lesions ER appear only when a high stimulus intensity is used. Lesions in the specific relay nuclei, ventralis posterior lateralis (VPL) have no effect on somatic ER in CN. Barbiturates (10 mg/kg) abolish somatic ER in CN. Stimulation of the ponto-mesencephalic reticular formation (RF) in a region where visual and somatic responses are recorded shows lowest threshold values for eliciting evoked responses in NCM and CN. The potentials in CN to RF stimulation are restricted to this nucleus and disappear in the internal capsule.

Afferent Pathways↗
PubMed1985

[Modulation of cutaneous evoked potentials during the period preparatory to a reaction time task in the cat].

Evoked potentials (EP) were elicited in four cats either when they sat still or when they performed a reaction time (RT) task. The foreperiod (FP) of the RT situation started with the cat placing his paw on a platform and ended 1.5 sec later with the vibration of the platform, used as a signal to withdraw the paw. The paw was electrically stimulated, once per trial, during the last second of the FP. Evoked potentials were recorded in the medial lemniscus (ML), in the thalamic nucleus centrum medianum (CM), in the internal capsule (IC) and over the anterior suprasylvian gyrus (ASSG). On the average, the EPs recorded in the CM, in the IC and over the ASSG (early and late waves) were significantly reduced during the FP. The EPs recorded in the ML did not show any significant change. The reduction in the EPs amplitude decreases along the FP, being the less at the time of arrival of the response signal. Neither the amplitude nor the time course of the EPs are correlated with the RT duration. These results are discussed with reference to the concepts of preparation for movement and of anticipation of the response stimulus.

Afferent Pathways↗
PubMed1982

Inspiratory onset or termination induced by electrical stimulation of the brain.

In anesthetized cats, electrical stimulation of the cerebral cortex and subcortical structures with short trains could induce onset or termination of activity of the phrenic nerve. Onset of phrenic discharge was obtained following stimulation of the primary sensory areas of the cerebral cortex, the periaqueductal gray, the ponto-mesencephalic reticular formation, the parabrachial nucleus, the vestibular nucleus, and the fastigial nucleus. When these structures were stimulated by repetitive trains at frequencies of 1-5 Hz, the respiratory rhythm was entrained to these same frequencies. The phrenic discharge during these repetitive stimulations exhibited a decrementing pattern similar to that during thermal polypnea. Termination of phrenic activity was obtained upon stimulation of the motor and visceral cortices, the internal capsule, the pyramidal tract, the red nucleus, the rubrospinal tract and the motor nucleus of the trigeminal nerve. Stimulation of these latter structures by repetitive trains resulted in a temporary or permanent arrest of phrenic discharge. These results are discussed in the context of the possible roles of medullary respiratory neurons in the onset or termination of inspiratory activity.

Animals↗
PubMed1981

The prolonged Q-T syndrome presenting as a focal neurological lesion.

A patient with a prolonged electrocardiographic Q-T interval suddenly developed left hemiplegia after an episode of ventricular fibrillation. A CT scan showed a cerebral infarction in the right internal capsule. The prolonged Q-T interval, by virtue of its association with cardiac arrhythmias, may cause cerebral hypoperfusion that commonly results in generalized neurological deficits. The lack of evidence for embolization in this patient suggests that decreased cerebral perfusion was responsible for the genesis of her neurological signs and symptoms. The prolonged Q-T interval is an easily overlooked cardiac abnormality that must be considered in a patient who exhibits a focal neurological deficit.

Adult↗
PubMed1985

Quantitative electron microscopic study of calcium accumulation in cerebral ischemia mitochondria.

Formation of calcium deposits in mitochondria is a consistent feature of irreversible injury in ischemic myocardium. We studied calcium accumulation in nerve cell mitochondria in a cat model 30 and 60 minutes after cerebral ischemia localized in the anterior part of the caudate nucleus and adjacent internal capsule. In control animals, calcium deposits were visible in synaptic vesicles, Golgi apparatus, mitochondria, lysosomes, and in glial and neuronal nuclei. After cerebral ischemia, findings included astrocytic swelling and degeneration of neurons, with an increase in calcium pyroantimoniate mitochondrial deposits. Content of intramitochondrial calcium deposits is related to duration of ischemia as well as the amount of cellular lesions.

Animals↗
PubMed1990

Selective occlusion of blood supply to the anterior perforated substance of the dog: a highly reproducible stroke model.

We created a highly reproducible stroke model in dogs by the selective occlusion of middle and anterior cerebral artery branches that penetrate the anterior perforated substance and supply much of the basal forebrain. We also analyzed the anatomic organization of the arterial supply to this region in this animal. Perforators came from anterior communicating artery branches similar to the recurrent artery of Heubner in humans and from the middle cerebral artery at several sites distal to the bifurcation of the internal carotid artery. Although some animals had a single source of the perforating arteries, most had two or more. In 50% of our specimens, the anterior communicating artery was the dominant source of arterial supply, in 21% the middle cerebral artery was dominant, and in 24% neither source dominated. Occlusion of all microscopically visible perforators to the anterior perforated substance reliably resulted in infarction of the internal capsule (100%), caudate nucleus (91%-100%), putamen or globus pallidus (82%-91%), and anterior commissure (73%). Structures involved less frequently in infarctions include the external capsule, claustrum, anterior commissure, and septal nuclei. We believe this anatomic information is useful for understanding why previous focal ischemia lesions in the distribution of the middle cerebral artery in the dog have been highly variable as well as for planning and interpreting future studies in this species. The proposed model of focal ischemia may be of use for the study of stroke.

Animals↗
PubMed1994

Selective intra-arterial chemotherapy with a combination of etoposide and cisplatin for malignant gliomas: preliminary report.

We administered selective intra-arterial chemotherapy consisting of a combination of etoposide and cisplatin to 20 patients with malignant glioma (seven with recurrent and six with enlarged tumors after initial treatment, and seven newly diagnosed patients). Evaluation of efficacy was based on computed tomographic and magnetic resonance imaging findings. In the process of establishing a safe technique for superselective intra-arterial chemotherapy, we encountered cerebrovascular accidents in two patients (after etoposide in one and after etoposide plus cisplatin in the other). In these two cases, 100 mg/m2 of etoposide and 100 mg/m2 of cisplatin were delivered via the horizontal segment of the middle cerebral artery (M1) or the tip of the basilar artery, with the infusion time reduced to 20 minutes. Thereafter, the etoposide was diluted, and the doses of both drugs were reduced to 80 or 50 mg/m2, and finally to 60 mg/m2, and both were infused over 60 minutes. In addition, for prevention of local spasm, papaverine hydrochloride and nicardipine were given via the same catheter at 5-minute intervals during administration of etoposide and cisplatin. No complications developed in the later cases. Thereafter, selective intra-arterial infusion of etoposide and cisplatin into the anterior cerebral artery, middle cerebral artery, posterior cerebral artery, or the basilar artery for malignant gliomas in the basal ganglia, internal capsule, and brainstem--a procedure generally considered risky in terms of potential complications--was performed safely, with tolerable side effects. Computed tomography and magnetic resonance imaging indicated improvement in 13 patients, including four whose tumors completely disappeared. This method of intra-arterial chemotherapy may be useful as an adjuvant treatment for malignant glioma.

Adolescent↗
PubMed1994

Total excision of a thalamic arteriovenous malformation using an orbito-fronto-malar approach: case report.

A 37-year-old woman was admitted to Osaka Neurological Institute after the sudden onset of left hemiplegia, hemihypesthesia, and ipsilateral hemianopia on February 4, 1992. Computed tomography (CT) disclosed the presence of hemorrhage in the right thalamus extending to the ipsilateral internal capsule. Cerebral angiography after CT scanning disclosed the presence of a cerebral arteriovenous malformation (AVM) fed by copsulothalamic and lateral geniculate body arteries originating from the right anterior choroidal artery. She was operated on with removal of the AVM using a right orbito-fronto-malar approach (OFM approach), which did not require transection of the cerebral parenchyma. The anterior choroidal artery could be followed distally from its origin and small feeding branches originating from the parent artery were easily identified, and the cerebral base could be examined in greater detail than with the conventional frontotemporal approach. The nidus could be excised in its entirety without difficulty. Postoperative angiography confirmed total excision of the AVM. She was transferred to another hospital for rehabilitation on April 13, 1992. Motor strength on the left side had improved to 3/5 by that time. The OFM approach appears to be potentially useful for the resection of inferolateral thalamic AVMs, because it does not require corticotomy and feeding branches can be identified and dealt with prior to other surgical manipulations.

Adult↗
PubMed1990

Analysis of voiding disorders in patients with cerebrovascular accidents.

Urodynamic evaluation was undertaken in 33 patients (15 males and 18 females, age range 48-90 years) with voiding problems following cerebrovascular accidents. In the majority of these patients (26) cystometry revealed involuntary contractions of the bladder. The critical volume for involuntary bladder contractions was approximately 200 mL. The majority of patients with cerebral cortex and/or internal capsule lesions had uninhibited relaxation of the sphincter during involuntary bladder contractions, while all of the patients with lesions only in the basal ganglia or thalamus had normal sphincter function. The remaining 7 patients had poor bladder contractions. Correlation of bladder dysfunction with the area of brain injury was not conclusive, but was suggestive of directions to be taken in future research.

Aged↗
PubMed1987

Characteristics of memory impairment in cerebral embolized rats at the chronic stage.

The effect of cerebral embolization on learning and memory in rats was studied at the chronic stage (8 weeks or more after embolization). At the chronic stage, embolized rats showed no significant change in emotional behavior, but exhibited an increase in ambulation in the open-field test. Rats with cerebral embolization exhibited marked impairment of the response was observed at the chronic stage. In a two-way active avoidance task, embolized rats showed accelerated acquisition of the avoidance response in comparison with a sham-operated control group. However, at the chronic stage, embolized rats exhibited marked impairment of light-dark discrimination learning. Spatial memory impairment was also observed in embolized rats, as demonstrated by a significant decrease in initial correct responses and an increase in total errors in the radial maze task. Upon microscopic examination, multi-focal necroses were detected in several brain regions, being particularly obvious in the hippocampus and internal capsule of the embolized hemisphere. These results demonstrate that embolized rats show definite impairment of memory and learning at the chronic stage, and suggest that the impairment may be qualitatively different from that observed at the early stage.

Animals↗
PubMed1987

Co-dergocrine, cerebral glucose utilization and maze performance in middle-aged rats.

The objective of this study was to determine the effect of co-dergocrine in rats on local cerebral glucose utilization and performance in a complex T-maze. Middle-aged (12-16 months) male Fischer-344 rats were given injections of co-dergocrine (3 or 10 mg/kg, IP) 35 min before behavioral testing or the administration of 2-deoxy-D-[1-14C]glucose ([14C]DG), a radiotracer for local cerebral glucose utilization (LCGU). Both doses stimulated LCGU in the locus ceruleus and median raphe nucleus and in subcortical structures associated with learning and memory (hippocampus and subiculum). The higher dose also stimulated LCGU in motor areas (caudate-putamen, globus pallidus, internal capsule). In contrast, co-dergocrine decreased LCGU in the frontal cortex. Poorer performance in a complex maze (increased shocks, errors and run time) was observed in middle-aged as compared with younger animals (3 months). Acute co-dergocrine treatment did not improve performance of middle-aged rats in this task. Thus, in the present experimental paradigm employing single dose administration, co-dergocrine's stimulation of LCGU was not associated with an alteration of maze performance in age-matched animals.

Age Factors↗
PubMed1990

Temporal dimensions of consonant and vowel production: an acoustic and CT scan analysis of aphasic speech.

This study explored a number of temporal (durational) parameters of consonant and vowel production in order to determine whether the speech production impairments of aphasics are the result of the same or different underlying mechanisms and in particular whether they implicate deficits that are primarily phonetic or phonological in nature. Detailed analyses of CT scan lesion data were also conducted to explore whether more specific neuroanatomical correlations could be made with speech production deficits. A series of acoustic analyses were conducted including voice-onset time, intrinsic and contrastive fricative duration, and intrinsic and contrastive vowel duration as produced by Broca's aphasics with anterior lesions (A patients), nonfluent aphasics with anterior and posterior lesions (AP patients), and fluent aphasics with posterior lesions (P patients). The constellation of impairments for the anterior aphasics including both the A and AP patients suggests that their disorder primarily reflects an inability to implement particular types of articulatory gestures or articulatory parameters rather than an inability to implement particular phonetic features. They display impairments in the implementation of laryngeal gestures for both consonant and vowel production. These patterns seem to relate to particular anatomical sites involving Broca's area, the anterior limb of the internal capsule, and the lowest motor cortex areas for larynx and tongue. The posterior patients also show evidence of subtle phonetic impairments suggesting that the neural instantiation of speech may require more extensive involvement, including the perisylvian area, than previously suggested.

Aged↗
PubMed1988

Tissue reaction to fabrics coated with turbostratic carbon: subcutaneous versus vascular implants.

A technique allowing the deposition of an adherent thin film of turbostratic, high-density carbon on heat-sensitive polymers was recently developed. The biological response to this biomaterial on yarns and fabrics of the type used in cardiovascular surgery has been studied. Polyester yarns, knitted Dacron sheets and knitted uncrimped Dacron vascular grafts were coated with a thin film (less than 1 micron) of turbostratic carbon using a physical vapour deposition process. Coated and control discs of knitted material, as well as coated and uncoated yarns, were implanted in pairs in the subcutaneous tissue of mice, using for each type of implant two cohorts of 12 animals, with observation periods of 4 and 8 wks respectively. Vascular grafts (8 cm long, 8 mm i.d.) coated with carbon on the luminal side only, were implanted for 12 wks in the infrarenal aortic position in six dogs, and compared to uncoated Dacron grafts of the same dimensions inserted in the same location and for the same duration in the infrarenal aortic position in six control animals. With subcutaneous implants, there was no significant difference in the tissue reaction to either coated or uncoated patches. In contrast, the vascular grafts, all of which were patent upon retrieval, showed a much lower extent of thrombosis on the blood-exposure surface in the case of carbon-coated Dacron, as compared to the luminal surface of control prostheses. The internal capsule (tissue formed between the polymer fabric and the blood interface) was thinner in carbon-coated grafts than in control grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

In vivo performance of the polyesterurethane Vascugraft prosthesis implanted as a thoraco-abdominal bypass in dogs: an exploratory study.

Among the various prototype vascular prostheses that have been developed over recent years as small vessel substitutes, the Vascugraft polyurethane device produced by Braun-Melsungen AG has a number of attractive features. As well as having high mechanical compliance similar to that of the arterial tree, it has been manufactured from a specially synthesized poly(ester urethane) with improved biostability and its microfibrous structure provides a highly porous wall with open communicating pores. With a view to evaluating the in vivo biofunctionality and biostability of this prosthesis in the dog, 10 mm diameter grafts were implanted as thoraco-abdominal bypasses for prescheduled periods of 1 months and 12 months, and their performance monitored in terms of gross morphology, histology and the measurement of the chemical and physical properties of the explanted and cleaned specimens. Both grafts were patent at retrieval. Each had a smooth and glistening flow surface without organized mural thrombi and showed the development of a thin collagenous internal capsule with the presence of endothelial-like cells. Both grafts were well encapsulated externally and revealed a small distal bend or kink which is frequently observed by any thoraco-abdominal bypass in dogs. The fresh explanted prostheses were cleaned by a new enzyme treatment which provided specimens for microscopic, mechanical and thermal analyses, as well as studies of the surface and bulk chemistry. By comparing the results from the explanted and cleaned material with those of the virgin prosthesis, we have observed some deterioration in the integrity of the microfibrous structure, some loss in mechanical performance, marginal changes in molecular weight, and an apparent microphase separation of the hard and soft segment domains at a depth of a few microns. While the biofunctionality of a 10 mm calibre device has been demonstrated, additional in vivo studies are recommended to assess the biofunctionality at different diameters and the biostability over longer periods of implantation.

Abdomen↗
PubMed1995

Carbodiimide cross-linked gelatin: a new coating for porous polyester arterial prostheses.

The performance of a polyester arterial prosthesis impregnated with gelatin and cross-linked with carbodiimide (Uni-graft) was compared with its porous parent graft (Protegraft) using a canine thoraco-abdominal bypass model. The grafts were investigated in terms of their handling characteristics, imperviousness at implantation, surface thrombogenicity and healing behaviour. Prostheses 30 cm in length were implanted for the following periods: 4, 24 and 48 h, 1, 2 and 4 weeks, 2, 3, 4, 5 and 6 months. Both types of graft had good handling characteristics. The ready-to-use impregnated graft provided satisfactory haemostasis at implantation with no blood permeating through the wall after flow was restored. Both grafts exhibited low surface thrombogenicity, as determined by the uptake of labelled fibrin and platelets, and the healing sequence of the impregnated graft after resorption of the gelatin was equivalent to that of the preclotted control. Biodegradation of the gelatin was complete within 1 month of implantation with the subsequent development of a collagenous internal capsule at both anastomoses. Endothelial cells were observed between 4 and 6 months, but were confined to small islets distributed along the luminal surface. The prostacyclin/thromboxane A2 (PGI2/TXA2) ratio, which gives an indication of the level of endothelial cell activity, was greater than 1.0 after 1 week of implantation for the control graft. For the impregnated graft it reached 1.0 only after 3 months of implantation, but remained above 1.0 for periods of up to 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗