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At least 163 records · Page 9Linked to original sources
PubMed1978

Myoclonus developing after vermisectomy in photosensitive Papio papio.

Two vermisectomized photosensitive baboons exhibited two different types of myoclonus, one induced by intermittent light stimulation (ILS) and the other occuring "spontaneously". The characteristics of these two types of myoclonus are described from a clinical and from an ECoG point of view. Myoclonus induced by ILS (ML) started at the eyelids and secondarily invaded the face and body; it was always preceded by frontorolandic spike-waves or polyspike-waves. The "spontaneous" myoclonus which followed vermisectomy (MV) was "massive", but involved firstly the trunk and secondarily the face and limbs; no ECoG paraoxysm accompanied this myoclonus, but we observed a parietal evoked potential of small amplitude, 10--15 msec after its onset. If MLs can be considered as consequences of the fronto-rolandic paroxysmal discharges, MVs seem to originate in the brain stem but appear similar to action myoclonus. This experimental situation showing two types of myoclonus resembles human hereditary degenerative syndromes (dyssynergic cerebellar myoclonus, progressive myoclonic epilepsy), without being exactly comparable. The conditions in which MVs were seen and their modifications during sleep and by different drugs are described. The relationships between MVs and MLs and myoclonic epilepsy are discussed.

Animals↗
PubMed1981

Opposite effects of lorazepam on two kinds of myoclonus in the photosensitive Papio papio.

The action of lorazepam was studied in photosensitive baboons. Animals were either naturally very photosensitive or rendered photosensitive by a previous injection of allylglycine. Intravenous administration of varying doses, from 0.05 to 0.5 mg/kg, of lorazepam blocked the myoclonus induced by intermittent light stimulation in all the animals. However, in the naturally photosensitive baboon the injection of lorazepam favoured the appearance of spontaneous myoclonus with no important EEG modification. This myoclonus is different from that induced by intermittent light stimulation, which is always preceded by spike-wave cortical discharges. Lorazepam-induced myoclonus appears during the period when the animal is not photosensitive and its origin is probably in the medulla or in the brain stem.

Animals↗
PubMed1981

Cerebral and extracerebral blood volume in generalized seizures in the baboon Papio papio.

Relative variations of the cerebral and extracerebral blood volume (CBV) were measured continuously by a novel atraumatic method in baboons to explore the relationship between changes in the systemic circulation and in the cerebral (and extracerebral) vascular responses, before, during and after generalized seizures induced by photic stimulation. Major bursts of generalized spikes and waves are accompanied by an increase of the mean arterial pressure and of the cerebral blood volume and a decrease of the nasal blood volume. During the seizure discharge a substantial increase in CBV occurs, associated with a dramatic increase in arterial pressure. However, the greatest increase in CBV occurs after the peak mean arterial pressure. The results show that the CBV does not passively follow the blood pressure and demonstrate the dramatic responsiveness of the nasal region to seizure discharge.

Animals↗
PubMed1984

The influence of intermittent light stimulation on potentials evoked by single flashes in photosensitive and non-photosensitive Papio papio.

The effects of intermittent light stimulation (ILS) on visual potentials (VEPs), evoked in different cortical areas, were statistically studied in baboons either naturally photosensitive or made photosensitive by allylglycine at a subconvulsant dose, as well as in non-photosensitive animals. VEPs were induced by single flashes (paradigm a) or by flashes preceded by trains of ILS (paradigm b). In every baboon, photosensitive or not, the VEPs induced by paradigm b in the striate area show a decrease of amplitude compared to VEPs induced by paradigm a. The ERG evolves in the same way. Therefore, these effects do not depend on photosensitivity; they depend on the intensity of stimulation. In photosensitive animals the single flash in paradigm b can induce a paroxysmal VEP in the fronto-rolandic (FR) area. In parietal and peristriate areas the VEPs induced by paradigm b show new late components when compared to those induced by paradigm a. These changes are observed even if no FR paroxysmal VEP is induced; they depend on the presence of a train of ILS preceding the single flash and on the predisposition to epilepsy (both natural and due to allylglycine); in the non-photosensitive animals the VEPs recorded in the same areas do not show such differences. We consider that among afferents which could act in inducing FR paroxysmal activities some cortico-cortical visual afferents can come from non-specific cortical areas (parietal or peristriate), but would not directly originate in the striate cortex; anatomical data in this species may support such a hypothesis.

Afferent Pathways↗
PubMed1989

Effects of localized, chronic GABA infusions into different cortical areas of the photosensitive baboon, Papio papio.

The effects of chronic (7 days) intracortical GABA infusions were investigated in both naturally photosensitive and non-photosensitive baboons. Bilateral and unilateral infusions into motor and occipital regions blocked photosensitivity, while premotor and prefrontal cortex infusions had no effect on the electro-clinical manifestations of this type of reflex epilepsy; the monkeys with prefrontal GABA infusions, however, showed selective attention deficits, detected with the delayed response test. In all cases a GABA withdrawal syndrome, appearing as epileptogenic spontaneous activity localized to the infused sites, was found at the cessation of GABA application. We conclude that GABAergic systems localized at discrete cortical areas play an important role in photosensitivity and in the modulation of cognitive processes in the monkey.

Animals↗
PubMed1985

Chemical synaptic transmission is not necessary for epileptic seizures to persist in the baboon Papio papio.

The spread and persistence of epileptic seizures have generally been attributed to chemical synaptic interactions. Using ion-sensitive microelectrodes, we showed that in the allylglycine-treated photosensitive baboon, prolonged light-induced generalized seizures were accompanied by abnormally large decreases in the concentration of extracellular calcium ions, reaching values at which chemical synaptic transmission was certainly very reduced or blocked. This feature was observed in all cortical layers. Measurements of the concentration of extracellular potassium ions in the course of such light-induced seizures indicated that the observed low values of the concentration of calcium ions could not be ascribed to the occurrence of spreading depressions. These findings showed that nonsynaptic mechanisms play a prominent role in the persistence of epileptic seizures.

Animals↗
PubMed1978

Identification of 7xi-hydroxytetrahydrocortisol and 7xi-hydroxytetrahydrocortisone from urine of newborn baboons (Papio papio).

Two highly polar, unconjugated metabolltes of tetrahydrocortisol and tetrahydrocortisone, which had been shown previously to account for greater than 40% of [14C]cortisol (F) administered to baboon neonates, were isolated from urine of a term newborn animal. Metabolites were extracted with ethyl acetate, purified by sequential paper chromatography and crystallization, and identified by chemical and biochemical procedures. Both metabolites of F are 5beta-pregnanes with a hydroxyl of unknown orientation at C-7, a 3alpha-hydroxyl, and a dihydroxyacetone side chain. The two compounds differ from each other by the presence of either oxo or hydroxyl functions at C-11. The following nomenclature is proposed: unknown 1: 3alpha,7xi,11beta,17,21-pentahydroxy-5beta-pregnan-20-one (7xi-hydroxytetrahydrocortisol); unknown 11: 3alpha,7xi,17,21-tetrahydroxy-5beta-pregnane-11,20-dione (7xi-hydroxytetrahydrocortisone). Production of these compounds compensates quantitatively for the decreased formation of F glucuronoside metabolites by baboon neonates, compared with that in adults. Therefore, we propose that 7-hydroxylation is a major alternative pathway for F metabolism in the perinatal period of the baboon.

Animals↗
PubMed1985

Different neuronal localization of aspartate-like and glutamate-like immunoreactivities in the hippocampus of rat, guinea-pig and Senegalese baboon (Papio papio), with a note on the distribution of gamma-aminobutyrate.

Antisera were raised in rabbits against aspartate or glutamate conjugated to bovine serum albumin by glutaraldehyde. After immunosorbent purification the antisera reacted selectively with brain protein-glutaraldehyde conjugates of the respective amino acids. These results from model systems encouraged us to employ the antisera to study the distribution of free aspartate and glutamate in brain tissue. The aspartate antiserum produced intense staining of interneurons and deep hilar neurons and modest labelling of pyramidal and granular cells in the hippocampal formation of rats, guinea-pigs and baboons perfusion-fixed with glutaraldehyde. In contrast, glutamate-like immunoreactivity was generally high in pyramidal and granular cells and low in interneurons. In hippocampal slices immersion fixed in glutaraldehyde after being soaked in Krebs' solution aspartate-like and glutamate-like immunoreactivities were lost from perikarya and dendrites. The staining that remained occurred in nerve terminal-like dots and matched the distribution of the major excitatory fiber systems, except that only glutamate-like immunoreactivity, and not aspartate-like immunoreactivity, was concentrated at the site of the mossy fiber terminals, and that aspartate-like but not glutamate-like immunoreactivity occurred between the granular and pyramidal cell bodies. The present technique specifically demonstrates aspartate and glutamate in glutaraldehyde-fixed tissue. We suggest that in perfusion-fixed material the staining intensities reflect the total concentrations of the amino acids (i.e. the "metabolic pool" plus the "transmitter pool"). In immersion-fixed hippocampal slices the "transmitter pool" may be preferentially visualized.

Animals↗
PubMed1995

A serial section study of visually normal posterior pelvic peritoneum from baboons (Papio cynocephalus, Papio anubis) with and without spontaneous minimal endometriosis.

OBJECTIVES: To determine if microscopic endometriosis exists in visually normal pelvic peritoneum from baboons with and without endometriosis. DESIGN: Observational histologic study at Institute of Primate Research, Nairobi, Kenya. SUBJECTS: Seventeen baboons including 13 adult females (5 with histologically proven endometriosis, 8 with a normal pelvis) and 4 juveniles (1 female and 3 males). INTERVENTIONS: Diagnostic laparoscopy with identification of visually normal pelvic peritoneum before euthanasia, followed by laparotomy with excision of a large area (at least 4 x 6 cm or 24 cm2 per animal, 408 cm2 surface in all baboons) of this visually normal-appearing peritoneum. MAIN OUTCOME MEASURE: Presence of microscopic endometriosis (endometrial glands and stroma) in serial sections of visually normal pelvic peritoneum. RESULTS: Two adjacent glandular structures compatible with endometriosis were found in normal peritoneum obtained during menses from one female baboon without macroscopic disease. Microscopic endometriosis was not detected in the other female primates with or without macroscopic disease or in male animals. CONCLUSION: Microscopic endometriosis was found in only 1 of 14 female baboons (prevalence 7%; 95% confidence interval 0% to 33%) with visually normal pelvic peritoneum. These findings suggest that, with the paucity of human data available, more studies are needed before concluding that massive microscopic disease exists in visually normal-appearing peritoneum of women.

Animals↗
PubMed1996

Disappearance of the ovulation stigma in baboons (Papio anubis, Papio cynocephalus) as determined by serial laparoscopies during the luteal phase.

OBJECTIVE: To investigate how long an ovulation stigma remains visible as determined by serial laparoscopies performed during the luteal phase in baboons. SUBJECTS AND SETTING: Sixteen female baboons with a normal pelvis (n = 6) and with endometriosis (n = 10) housed at the Institute of Primate Research, Nairobi, Kenya. INTERVENTIONS: Fifty-six laparoscopies were carried out before ovulation (n = 7) and serially during the luteal phase (n = 49; 3 +/- 1 per baboon): 1 to 2 days (n = 2), 4 to 5 days (n = 15), 8 to 9 days (n = 11), 12 to 13 days (n = 12), and 16 to 17 days (n = 9) after ovulation. MAIN OUTCOME MEASURE: During each laparoscopy the ovaries were screened systematically for the presence and size of an ovulation stigma and/or corpus luteum (CL). RESULTS: When the laparoscopy was done within 5 days after ovulation, a fresh ovulation stigma was observed in all nine baboons with a normal pelvis or minimal endometriosis, but only in four of seven animals with mild to severe disease. If a fresh ovulation stigma had been observed within 5 days after ovulation (n = 13), it gradually became smaller but remained visible 8 to 9 days after ovulation in 91%, at 12 to 13 days after ovulation in 75%, and at 16 to 17 days after ovulation in 50% of the primates. CONCLUSION: If a fresh ovulation stigma was observed in baboons within 5 days after ovulation, it diminished in size but remained visible up to 8, 12, and 16 days after ovulation in 91%, 75%, and 50% of animals, respectively. Therefore, diagnostic laparoscopies for the detection of an ovulation stigma in baboons should be performed in the early luteal phase.

Animals↗