Factors influencing the cholinesterases of cerebrospinal fluid in the anaesthetized cat

Both acetylcholinesterase and non-specific cholinesterase are found in cerebrospinal fluid and blood plasma of the cat; the ratio of activities acetylcholinesterase/non-specific cholinesterase is about 1.5 in cerebrospinal fluid and 0.15 in plasma. A search was made for factors capable of influencing the concentration of the two cholinesterases in cerebrospinal fluid. Either the ventricular system was perfused with artificial cerebrospinal fluid from a lateral ventricle to the aqueduct, or the atlanto-occipital membrane was punctured and cerebrospinal fluid was collected continuously from the cisterna magna. Factors studied included: (a) procedures affecting the composition or formation of cerebrospinal fluid, such as changes in the ionic constituents of the perfusate, the inhibition of cerebrospinal fluid formation by acetazolamide or ouabain, or the rapid intra-carotid infusion of hypertonic urea; (b) arousal (noise or stimulation of the central ends of the sciatic nerves), or deepening of anaesthesia; (c) changes in blood pressure; (d) central stimulants and depressants, pyrogens, prostaglandins, antagonists of acetylcholine. Whereas most procedures or drugs tested increased the concentration of acetylcholinesterase, some central depressants (e.g. chlorpromazine) reduced, while another (ether) increased the appearance of acetylcholinesterase in the cerebrospinal fluid. The effect of ether was, in all probability, due to damage to the blood-brain barrier. A rise in acetylcholinesterase concentration was obtained upon stimulation of the central ends of the sciatic nerves; this was inhibited by atropine but not by N-methylatropine, indicating that the rise was due to increased nervous activity and not to the circulatory effects of the stimulation, since the changes in blood pressure caused by the stimulation remained the same after atropine administration. Amphetamine or leptazol raised the levels of acetylcholinesterase but it was not possible to determine whether this was due only to increased central nervous activity, since there was invariably leakage through the blood-brain barrier which by itself would be sufficient to produce the effect. A rise in the level of acetylcholinesterase was seen after administration of pyrogen; this was apparently not a simple effect of warming the body, but due to the action of the pyrogen on centers concerned with temperature control, since warming the animal by external heat failed to produce a similar change.(ABSTRACT TRUNCATED AT 400 WORDS)     

The influence of cerebral 5-hydroxytryptamine on catalepsy induced by brain-amine depleting neuroleptics or by cholinomimetics

1 Catalepsy was produced in rats and mice by the subcutaneous injection of either tetrabenazine or the butyrophenone U-32,802A (4′-fluoro-4-{[4-(p-fluorophenyl)-3-cyclohexen-1-yl]amino} butyrophenone hydrochloride). Catalepsy was evaluated by the duration of total immobility on a vertical grid.

2 Pretreatment with p-chlorophenylalanine (PCPA) reduced the intensity of catalepsy by 50% or more, whereas its time course remained the same.

3 5-Hydroxytryptophan (5-HTP), 10 mg/kg, enhanced the catalepsy induced by U-32,802A or tetrabenazine, provided it was administered soon (45 min) after the neuroleptic; injections at 90 min had no effect. Otherwise untreated rats given this dose of 5-HTP behaved normally on the grid.

4 The anticataleptic effect of PCPA was reversed by 5-HTP.

5 Measurable changes in 5-hydroxytryptamine (5-HT) metabolism in the rat forebrain accompanied the modification of catalepsy by 5-HTP and PCPA.

6 Methysergide (5 mg/kg) given 30 min before the neuroleptics to either mice or rats reduced the catalepsy, assessed 2.5 h after the methysergide. It also prevented the increase in neuroleptic-induced catalepsy following 5-HTP, 10 mg/kg.

7 Tryptophan, like 5-HTP, increased the catalepsy seen in mice after U-32,802A and tetrabenazine, and increased the production of 5-hydroxyindol-3-ylacetic acid in the forebrain.

8 In the rat, intracerebroventricular injection of physostigmine produced catalepsy which was not modified by methysergide or PCPA but was abolished by atropine. Similarly, in the mouse, catalepsy induced by the subcutaneous injection of pilocarpine was abolished by atropine but not affected by either methysergide or 5-HTP.

9 Atropine greatly reduced the catalepsy induced by U-32,802A and tetrabenazine but lowered striatal homovanillic acid (HVA) only after U-32,802A. D,L-DOPA, 20 mg/kg, diminished the cataleptogenic effect of both neuroleptics and raised striatal HVA.

10 The results support the view that there is a facilitating or permissive action of 5-HT-containing neurones on neuroleptic-induced catalepsy.

     

Utilidad de la ultrasonografía endoscópica (USE) en Oncología

Endoscopic ultrasound (EUS) consists in a flexible endoscopy with high frequency ultrasonic transducer at the tip, allowing to visualize the different layers of the intestinal wall and an area of 6 cm around. Thus, EUS is the best technique to determine the infiltration deep of the tumor in digestive neoplasms and to evaluate lymph node staging of tumors of the gastrointestinal tract and lung cancer. The aim of this article is to review the indications, limitations and accuracy of EUS in the digestive and non small lung cancer staging.     

The effect of fasting on 5-hydroxytryptamine metabolism in brain regions of the albino rat.

The turnover of 5-hydroxytryptamine (5-HT) in the whole brain and different brain regions was studied in rats fasted for 24 h. These rats showed an increased tissue concentration of the amine in the whole brain and of its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the whole brain, the striatum, the combined pons-medulla and the cerebral cortex. The accumulation of 5-HIAA after probenecid was increased by fasting in the regions mentioned above except for the striatum. The effect of probenecid was also increased by fasting in the midbrain, the hypothalamus and the hippocampus. In the striatum, the administration of probenecid produced a smaller increase in 5-HIAA concentration in fasted than in fed rats. The decay of 5-HT following p-chlorophenylalanine (PCPA) was increased in the hypothalamus of fasted rats at 16 h, but not at 4 h, after the intraperitoneal administration of the inhibitor. In the midbrain, the striatum and the combined pons-medulla, food deprivation did not modify the decrease induced by PCPA. However, the inhibitor induced a reduction of food consumption in the fed group, which made this group rather similar to the fasted one and complicated the interpretation of the results in these last three cerebral areas. Our results confirm that food deprivation increases the turnover of brain 5-HT and point out that the increase probably occurs in all brain areas. This increased turnover appears to be accompanied, in the hypothalamus, by an increased neuronal release of the amine. In the striatum, fasting probably blocks the active transport system which removes acid metabolites from the brain.     

Growth and micronutrient status in children receiving a fortified complementary food

Linear growth retardation and anemia are the most prevalent nutritional problems in the world; effective interventions are urgently needed. We evaluated Ecuador's National Food Nutrition Program (PANN 2000) that included a micronutrient-fortified complementary food (FCF), Mi Papilla, in poor periurban and rural communities of Ecuador. The program is preventive and targeted to all infants and young children living in poor communities and receiving government health services. We compared dietary intake, micronutrient status, and growth over 11 mo in a cohort of children from the catchment areas of the PANN 2000 with same-age control children in nearby communities eligible to enter the program 1 y later. PANN 2000 children enrolled in the program when they were age 9-14 mo and were age 20-25 mo at the final survey. They consumed significantly more energy, protein, fat, iron, zinc, vitamin A, and calcium than control children because of their FCF consumption. Anemia, 76% in both groups at baseline, fell to 27% in PANN 2000 children but only to 44% in control children (P < 0.001). The odds of being anemic were 58% lower for PANN 2000 children (P = 0.003). The effects on linear growth and weight were limited to children who were older when the program began (12-14 mo) and were significant for weight (interaction with age, 0.38 kg; P = 0.029) and positive but not significant for length (0.66 cm; P = 0.08). An FCF, including ferrous sulfate, delivered through public health services, is highly effective in improving weight and hemoglobin and reducing anemia.     

Left ventricular cineangiography in Chagas' disease: Detection of early myocardial damage

The purpose of this investigation was to identify early left ventricular (LV) cineangiographic signs of myocardial damage and to study the evolution of the characteristic lesions in 126 chronic chagasic patients, divided into three groups. Group I patients had no clinical, ECG, or radiologic evidences of heart disease; 41% of them manifested apical or anterior apical asynergy, suggestive of early subclinical myocardial damage. Group II patients had abnormal ECG findings and no clinical signs of heart failure. Extensive asynergy, LV dilatation, decreased distensibility, and depressed contractility were found in 98% of these cases. Group III patients presented with congestive heart failure, a greatly dilated, hypokinetic LV chamber, and a 40% incidence of large apical aneurysms, 20% with thromboses within the LV. The performance of a left cineventriculogram in our chagasic patients enabled us to diagnose early myocardial damage and to detect potentially resectable lesions, such as ventricular aneurysms and apical thromboses.     

Early resolution of Ogilvie's syndrome with intravenous neostigmine

PURPOSE: Our aim was to assess the value of a parasympathomimetic drug (neostigmine) in the early resolution of acute colonic pseudo-obstruction (Ogilvie's syndrome). METHODS: A prospective study was undertaken in 18 consecutive patients (mean age, 76 (range, 31–87) years) with acute colonic pseudo-obstruction. After a varying period of conservative treatment in all cases, 16 patients with persistent, massive abdominal distention were given intravenous neostigmine. RESULTS: A rapid and satisfactory clinical and radiologic decompression of the large bowel was obtained in 12 patients (75 percent) after a single dose of the drug; another patient had complete resolution after a second dose, and the other 3 patients had only partial resolution, in one of them after a second dose of the drug. No patient required surgical decompression of the bowel. CONCLUSION: These results give support to the theory of excessive parasympathetic suppression in most cases of Ogilvie's syndrome. The treatment with intravenous neostigmine has proved very effective, preventing in many cases prolonged periods of uncomfortable and potentially hazardous conventional conservative management and avoiding surgical treatment in a consecutive series of patients.Presented in part at the XIX Congress of the European Federation of the International College of Surgeons (ICS)-National Congress of the Spanish Section of the ICS, Tenerife, Spain, October 12 to 14, 1995.