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C Mathis

Publications and source records attributed to C Mathis.

At least 55 records · Page 3Linked to original sources
PubMed1994

Vagal control of transpyloric flow and pyloric resistance.

Vagal control of pyloric resistance was evaluated in anesthetised pigs by recording gastropyloroduodenal motility and transpyloric flow during emptying of a liquid nonnutrient meal. Vagotomy did not modify pyloric resistance or the characteristics of the flow pulses. Electrical stimulation of the distal stumps of cervical or thoracic vagus nerves decreased pyloric resistance and triggered flow pulses of large stroke volume. This was associated with increased fundic tone and pressurization of the antrum. Phentolamine but not propranolol reduced the responses to vagal stimulation. These observations demonstrate that reduced pyloric resistance is one mechanism by which vagal activation promotes transpyloric flow.

Animals↗
PubMed1994

Antropyloric modulation of transpyloric flow of liquids in pigs.

BACKGROUND/AIMS: The proximal stomach is considered as the main contributor to liquid emptying. The aim of this study was to investigate the capacity of the distal stomach to generate transpyloric flow pulses in the absence of the proximal stomach. METHODS: Concurrent motility and flow measurements were made in eight anesthetized pigs. Four animals had the proximal stomach excluded by creation of a mucosal septal pouch. RESULTS: Although major modifications of both flow pulse and motility patterns resulted from proximal stomach exclusion, emptying remained pulsatile and overall emptying rate unchanged. After proximal stomach exclusion, backflow disappeared and flow pulses occurred simultaneously with antral and pyloric pressure events, whereas flow pulses preceded the pressure events in intact animals. The frequency of flow pulses decreased after proximal stomach exclusion because the interval between gastroduodenal pressure events was longer. In contrast, there was an increase in the stroke volume of flow pulses attributable to a decrease in pyloric resistance. CONCLUSIONS: Exclusion of the proximal stomach does not modify the overall emptying rate, although the mechanisms responsible for emptying are modified. In particular, the stroke volume of individual pulses is greater.

Animals↗
PubMed1993

Evaluation of [3H]paroxetine as an in vivo ligand for serotonin uptake sites: a quantitative autoradiographic study in the rat brain.

Paroxetine, a selective inhibitor of serotonin uptake and an antidepressant, was used in conjunction with quantitative ex vivo autoradiography to study the feasibility of imaging serotonin terminals in the living brain. Tritiated paroxetine was injected in the rat tail vein, and the brain was processed for quantitative autoradiography 3 hours later. Animals received either [3H]paroxetine alone (100 microCi/animal) or a mixture of labeled paroxetine (100 microCi) and an excess of unlabeled drug (0.5 or 2 mg/kg intravenously [i.v.]). Computerized image analysis of the resulting autoradiograms revealed high densities of radioactivity in brain regions known to contain high densities of serotonergic terminals and high specific binding of [3H] paroxetine in vitro, such as the raphe nuclei, interpeduncular nucleus, basolateral amygdala, substantia nigra, and some hypothalamic nuclei. Radioactivity uptake in these brain regions was effectively blocked (50-72%) by coadministration of excess unlabeled paroxetine. However, cortical and hippocampal binding of paroxetine in vivo was moderately high, in contrast to the relatively sparse serotonergic innervation in these regions. Only a relatively small proportion of cortical and hippocampal binding (20-40%) could be blocked by excess unlabeled paroxetine, indicating that most of the radioactivity in these regions is not associated with serotonin terminals or uptake sites. The usefulness of [3H]paroxetine as an in vivo ligand for imaging serotonin terminals in the human brain is limited by these nonserotonergic binding sites.

Animals↗
PubMed1993

[Major hypercalcemia disclosing sarcoidosis].

Sarcoidosis is exceptionally revealed by major isolated hypercalcemia. To the 4 cases already published, we are adding this one. A review of the literature is presented, focussed on the frequency and characteristic features of the hypercalcemia associated with sarcoidosis, as well as its physiopathology: an overproduction by granulomatous cells of 1-25 dihydroxyvitamin D3 evading the usual regulatory mechanisms. Treatment rests on corticosteroid therapy and sometimes hydroxychloroquine.

Calcitriol↗
PubMed1992

The selective protein kinase C inhibitor, NPC 15437, induces specific deficits in memory retention in mice.

We studied the effects of a selective inhibitor of protein kinase C (PKC), 2,6-diamino-N-[(1-(1-oxotridecyl)-2-piperidinyl]methyl)hexamide (NPC 15437), on acquisition and memory retention of a Y-maze avoidance task in mice. Post-training administration of NPC 15437 (0.1-10 mg/kg i.p.) induced a dose-dependent deficit in retention of the temporal but not the spatial component of the task. This selective amnesia does not reflect state dependence and NPC 15437 (1 mg/kg) had no effect on acquisition and memory retrieval. Our results suggest that this new PKC inhibitor interferes with mechanisms underlying memory consolidation. This is in agreement with recent findings suggesting that PKC is involved in memory processes.

Amnesia↗
PubMed1992

Corticosteroid injection of the sacroiliac joint in patients with seronegative spondylarthropathy.

OBJECTIVE: We report our experience with the use of corticosteroid injections into the sacroiliac joint in the treatment of patients with seronegative spondylarthropathy. METHODS: We performed 42 injections, constituting 24 procedures in 22 patients (2 patients had the procedure performed twice). RESULTS: The response was considered very good or good in 19 of 24 procedures (79.2%) and 34 of 42 joints (81%). Improvement persisted in 14 patients after a mean +/- SD followup time of 9.6 +/- 4.2 months. CONCLUSION: This technique appears to be safe, easy to apply into ambulatory patients, and quite effective.

Adolescent↗
PubMed1992

Comparative analysis of seizures induced by intracerebroventricular administration of NMDA, kainate and quisqualate in mice.

The dose-related time course and occurrence of different seizure subtypes was examined in mice after i.c.v. administration of N-methyl-D-aspartate (NMDA), kainate (KA) or quisqualate (QA). At doses of 0.2 to 1 nmol, NMDA dose-dependently induced a single clonic-tonic seizure. Low doses (0.1 to 0.3 nmol) of KA induced only mild myoclonus and whole body clonus, which were dose-dependently replaced by short-delay clonic-tonic seizures at higher doses (0.4 to 1.2 nmol). In contrast, mice treated with 13 to 32 nmol of QA exhibited either mild myoclonus or whole body clonus as well as clonic-tonic seizures. Clonic-tonic seizures induced by NMDA or KA appeared at shorter latencies than those induced by QA, whereas whole body clonus induced by KA or QA appeared with long onset latencies. These results clearly show that i.c.v. administration of NMDA, KA and QA produces different patterns of seizures in mice. This study confirms that NMDA, KA and QA induce convulsions through different underlying mechanisms and suggests that different anatomical pathways are involved in these models.

Animals↗
PubMed1992

Pharmacologic maintenance of abstinence in patients with alcoholism: no efficacy of 5-hydroxytryptophan or levodopa.

Pharmacologic enhancement of central nervous system serotonin and dopamine functions has been postulated to improve maintenance of abstinence in patients with alcoholism. To test this hypothesis, patients with alcoholism who completed a 42-day inpatient treatment program were randomized to be administered, in a double-blind fashion, either 5-hydroxytryptophan and carbidopa, levodopa and carbidopa, or placebo for 1 year. Eight of 31 patients who entered the analysis remained abstinent from alcohol for 1 year; however, there was no significant effect of the treatment condition on maintenance of abstinence. Baseline psychologic measures showed that patients who abstained from alcohol had more education and higher scores on memory function tests. Measures of cerebrospinal fluid obtained before the start of the study indicated that all patients who had higher concentrations of the dopamine metabolite homovanillic acid relapsed, suggesting that further research is needed to elucidate the role of dopamine in alcoholism.

5-Hydroxytryptophan↗
PubMed1991

The NMDA receptor antagonists, CPP and gamma-L-glutamyl-L-aspartate, selectively block post-training improvement of performance in a Y-maze avoidance learning task.

Behavioral effects of CCP and gamma-L-glutamyl-L-aspartate (gamma-LGLA) were studied in a Y-maze avoidance learning task. Male Swiss mice had to leave the start alley of the maze within the first 5 s of a trial (temporal component) and to choose the left alley (spatial component) to avoid footshocks; they were trained to a criterion of 7 correct out of 8 consecutive trials. CPP and gamma-LGLA when administered immediately following the learning session (0.025-200 mumol/kg, i.p.) significantly impaired retention 48 h later at doses of 0.025-0.25 and 0.25-25 mumol/kg, respectively, but had no significant effect at higher doses. CPP, when administered 30 min before the learning session (0.025-25 mumol/kg) did not affect learning acquisition at any dose, whereas it significantly impaired retention 48 h later but only at the doses of 0.025-0.25 mumol/kg. CPP and gamma-LGLA did not erase all memory traces; posttraining performances on the temporal component, which significantly improved in control animals during the hours following acquisition, were much more affected by CPP and gamma-LGLA than posttraining performances on the spatial component which did not improve over time in controls. Moreover, CPP (0.025-25 mumol/kg) had no effect on spatial recognition memory in an alternation task in which no spontaneous improvement of posttraining performance was observed in controls. These results strongly suggest that CPP and gamma-LGLA interfere with mechanisms underlying posttraining organization of memory traces and that NMDA receptors are involved in this action.

Animals↗
PubMed1991

Memory deficits induced by gamma-L-glutamyl-L-aspartate and D-2-amino-6-phosphonovalerate in a Y-maze avoidance task: relationship to NMDA receptor antagonism.

Post-training administration (ICV) of gamma-L-glutamyl-L-aspartate (gamma-LGLA) or D-2-amino-5-phosphonovalerate (D-AP5), a competitive NMDA antagonist, decreased retention of the temporal component but not the spatial discrimination component of a Y-maze active avoidance task. Inverted U-shaped dose-response curves were obtained for the ability of gamma-LGLA and D-AP5 to decrease retention, with maximum effects occurring at doses of 2-20 nmol/mouse for gamma-LGLA and 0.02 nmol/mouse for D-AP5. gamma-LGLA and D-AP5 impaired the traction reflex only at doses (80 and 2 nmol/mouse, respectively) higher than those producing retention deficits. Convulsions induced by ICV administration of 1 nmol NMDA were antagonized by gamma-LGLA and D-AP5 with ED50 values of 46 (32-66) and 0.2 (0.16-0.25) nmol/mouse, respectively. The dose-effect curve of NMDA for producing convulsions was shifted to the right in a parallel manner and to the same extent by 80 nmol gamma-LGLA and by 0.3 nmol D-AP5. Taken together, these results are consistent with previous studies suggesting that the behavioral effects of gamma-LGLA might be related to its NMDA receptor antagonist properties. The selectivity of the memory deficits induced by gamma-LGLA and D-AP5 is in agreement with recent reports suggesting a role for NMDA receptors in the mechanisms underlying posttraining organization of memory traces.

2-Amino-5-phosphonovalerate↗
PubMed1990

NMDA antagonist properties of gamma-L-glutamyl-L-aspartate demonstrated on chemically induced seizures in mice.

In order to determine the gamma-L-glutamyl-L-aspartate (gamma-LGLA) site of action in excitatory amino acids (EAA) systems, we studied the gamma-LGLA anticonvulsant activity against seizures induced in mice by pentylenetetrazol, picrotoxin and EAA agonists. The mice were protected against seizures induced by pentylenetetrazol (80 mg/kg s.c.) and picrotoxin (2.75 mg/kg s.c.) after intraperitoneal administration of gamma-LGLA with two significant peak effects around the doses of 0.25 and 200 mumol/kg as revealed by the dose-response curves obtained in both experiments. Use of an intracerebroventricular co-injection procedure showed that gamma-LGLA dose dependently suppressed the seizures induced by NMDA (1 nmol/mouse) with a maximal effect at 80 nmol/mouse but, at the same dose, it only slightly suppressed seizures induced by kainate (0.3 and 0.8 nmol/mouse) or by quisqualate (18.5 nmol/mouse). The anticonvulsant activity of gamma-LGLA on these chemically induced seizures is consistent with an antagonistic action of gamma-LGLA on NMDA receptor subtypes.

Animals↗
PubMed1988

Chest radiography in infant cardiac allotransplantation.

Heart transplants were performed in seven infants at Loma Linda University Medical Center from 1985 to 1987. Five of these seven patients survived. In this report, the radiographic appearance of the chest is presented before surgery, immediately after surgery, and during a documented episode of rejection. The most current available chest radiograph is also presented. Acute rejection was confirmed by clinical, echocardiographic, and ECG findings. The only pulmonary infection encountered was mycoplasma pneumonitis. Four patients developed gastrointestinal rotavirus infections and were shown to have dilated proximal small-bowel folds on upper gastrointestinal studies. At the time of this writing, the prognosis for the five surviving infants is good. We conclude that the radiographs of infants who have received heart transplants show an unusual cardiac contour and slight cardiomegaly. Increasing cardiomegaly can alert one to early rejection. Prominent folds in the small bowel are of uncertain origin and significance, but they may be related to infection resulting from immunosuppression.

Female↗
PubMed1986

Size and X-ray density of normal and denervated muscles of the human leg and forearm.

An accurate assessment of muscle size and tissue density can be obtained by X-ray computed tomography. CAT scans of the extensor and flexor muscle compartments of the leg and forearm were performed on normal subjects to establish: normal ranges of muscle densities, and the effect of sex and side dominance on muscle size and density. The same muscle groups were studied in patients with nerve damage resulting in either total or very extensive denervation of the corresponding muscle compartments. In normal subjects muscle density is significantly lower in females and the effect of side dominance is more marked in the upper extremity. Denervated muscle compartments show reduced cross-section and density. Electrotherapy does not appear to be effective in preventing muscle atrophy.

Absorptiometry, Photon↗