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Biomedical subjects

E Montoya

Publications and source records attributed to E Montoya.

At least 73 records · Page 4Linked to original sources
PubMed1975

Interactions between Azotobacter and "phosphobacteria" and their establishment in the rhizosphere as affected by soil fertility.

The effects on plant growth of "bacterial fertilizers" prepared from Azotobacter spp. and phosphate-solubilizing bacteria ("phosphobacteria") have been the subject of much controversy. Cases where no plant-growth stimulation occurred may often be accounted for by the failure to establish the bacterial inocula in the rhizosphere. Three factors that may influence inocula establishment, i.e. soil fertility, manuring, and interactions between Azotobacter and "phosphobacteria," were examined in pot experiments, designed for statistical analysis, in two neutral-alkaline soils, using lavender plants (Lavandula spica L.). During the experiments the numbers of Azotobacter and "phosphobacteria" were counted. Dry weights of roots and shoots were recorded after 16 weeks of growth. At the end of the experiments there were always more Azotobacter and "phosphobacteria" in the rhizospheres when plants were inoculated with both groups of organisms together than when they were inoculated singly. Addition of 2% farmyard manure to the richer soil enhanced this effect. Plant growth was greatest when seedlings were inoculated with both Azotobacter and the "phosphobacteria".

Azotobacter↗
PubMed1975

Thyrotropin-releasing hormone secretory physiology: studies by radioimmunoassay and affinity chromatography.

Thyrotropin-releasing hormone (TRH) in rat blood and mathanol extracts of hypothalami has been quantified by a specific TRH radioimmunoassay, in conjunction with TRH affinity chromatography. Blood TRH was found to be elevated dramatically after 1 h by the physiologic stimulus, ambient cold (4 C), which was also attended by a 2-fold rise in serum thyrotropin (TSH). The acute administration of parenteral triodothyronine (T3) over a period of 48 h prior to identical cold exposure completely abolished the rise in serum TSH. Blood TRH however, rose in a fashion qualitatively similar to that seen in euthyroid animals. Similarly, chronic induction (32 days) of experimental euthyroidism, hypothyroidism, and hyperthyroidism, which altered metabolic states were corroborated by measurement of serum thyroxine (T4) and TSH, did not result in any significant changes in either the hypothalamic content or blood concentration of TRH. These data provide direct documentation that the regulatory control of pituitary TSH secretion by T4 and/or T3 is not mediated by inhibiting the hypothalamic secretion of TRH, but presumably by inhibiting the actions of TRH at the level of the pituitary thyrotroph cell.

Animals↗
PubMed1975

Thyrotropin-releasing hormone (TRH): Measurements in human spinal fluid.

Levels of thyrotropin-releasing hormone (TRH) were quantitated in human lumbar spinal fluid (CSF) utilizing a sensitive and specific TRH radioimmunoassay. Endogenous TRH was sufficiently stable in CSF to permit 85% recovery of intact TRH after 48 h storage at 4 C. TRH levels in AM or PM samples obtained from 15 women and 12 men were easily detected in all CSF specimens. No significant difference between the TRH concentration in CSF of men and women was observed (44.2+/-6.8 and 38.1+/-6.5 pg/ml (mean+/-SE) respectively). TRH concentrations were 40.2+/-6.9 pg/ml (mean+/-SEM) in AM and 41.4+/-8.0 pg/ml in PM samples. By contrast, CSF cortisol levels obtained concurrently were twofold higher in AM than PM (0.68+/-0.08 vs 0.38+/-0.02 mug/100 ml (mean+/-SEM) respectively, P less than 0.001). These data are consistent with the possibility that a portion of the TRH in CSF can be derived from the central nervous system (CNS) and unrelated to the hypo-physiotropic control of thyrotropin (TSH) synthesis and secretion.

Circadian Rhythm↗
PubMed1972

Effects of hypo- and hyper-thyroidism on liver composition, blood glucose, ketone bodies and insulin in the male rat.

1. Thyroidectomized rats injected daily with 0, 0.1, 2 or 25mug of l-thyroxine/100g body wt. were compared with intact controls. In plasma, the protein-bound iodine was decreased in the rats given the 0 or 0.1mug doses and increased in those given the 25mug dose. 2. Blood glucose decreased in those given 2mug and was augmented in those given 25mug, and ketone bodies were the same in all the groups. 3. Plasma insulin was lowest in the rats given the 0 or 0.1mug doses and was highest in those given the 2 or 25mug doses of thyroxine. 4. After 48h starvation, the decrease in blood glucose and increase in ketone bodies observed in all the groups was greatest in the group not supplemented with thyroxine. 5. Plasma insulin concentrations remained at the value for fed animals in the rats given the 25mug dose of thyroxine but decreased in the other groups. 6. In fed animals, concentrations of hepatic DNA P, citrate, total fatty acids and acetyl-CoA were similar in all the groups, and glycogen was low only in the rats given the 25mug dose of thyroxine. 7. After 48h starvation, liver DNA P, total fatty acids and acetyl-CoA increased in all the groups, except in the rats given the 25mug dose, where both total fatty acids and acetyl-CoA remained at the value for fed animals. Liver citrate did not change in the groups given the 0 or 25mug doses of thyroxine, but decreased in the other groups. 8. The results are discussed in relation to the regulation of intermediary metabolism in hypo- and hyper-thyroidism.

Animals↗
PubMed1967

Toxohormone from normal tissues.

The presence of toxohormone-like factor in autolysates of animal tissues was investigated. One could always isolate appreciable quantities of preparations having toxohormone activity. At the doses tested, no activity could be shown in preparations from nonautolyzed tissues. We suggest that autolysis phenomena may cause the presence of toxohormone in tumor-bearing organisms.

Animals↗
PubMedDate not supplied

Spontaneous cardiomyopathy resembling acute rheumatic heart disease in an owl monkey.

A wild-caught male Aotus vociferans died spontaneously during quarantine. Histologic examination of the heart showed several small myocardial arteries replaced with fibrinoid necrosis and adjacent inflammation that included lymphocytes and large histiocytic cells. Less often, similar inflammatory foci were observed in the myocardium interstitium. The lesions observed in the heart of the owl monkey resembled Aschoff bodies.

Acute Disease↗
PubMedDate not supplied

Pasteurella haemolytica infection in a Goeldie's monkey.

An adult male Callimico goeldii died spontaneously. At necropsy, small whitish foci were found randomly distributed on the liver surface. Histologically, the foci were composed of mixed inflammatory cells with predominant polymorphonuclear cell infiltration and central areas of necrosis. Microbiological cultures revealed a Gram-negative coccoid-bacilli with bipolar staining. Biochemical analysis revealed that the microorganism was Pasteurella haemolytica.

Animals↗
PubMedDate not supplied

[T-L mucosa to mucosa pancreatojejunal anastomosis for pancreatic reconstruction following a duodenopancreatectomy].

INTRODUCTION: The pancreatojejunal anastomosis is considered the weak spot when carrying out a duodenopancreatectomy, because it causes most of the complications following a Whipple surgery. Here we present a series of cases using a single technique for performing this anastomosis. MATERIAL AND METHODS: During the period between October 2002 and August 2005, 49 duodenopancreatectomies were performed at the 3AII Department of the National Hospital Edgardo Rebagliati Martins - H.N.E.R.M., in 31 of these cases a lateral mucosa to mucosa pancreatojejunal anastomosis was carried out by the same surgeon. RESULTS: The most frequent complication was infection of the operating wound followed by pancreatic fistula and intra-abdominal hemorrhage and the overall morbidity was 29%. Pancreatic fistula developed in 13% of the cases; however, no patient required additional treatment and the fistula closed maximum twenty days after the surgery. On average, patients resumed oral food intake after 6 days and remained hospitalized for 16 days. Mortality was 3%, because a patient developed a pseudo-aneurism of the hepatic artery, which ruptured 17 days after the operation. CONCLUSIONS: The mucosa to mucosa pancreatojejunal anastomosis is a safe technique with a low index of pancreatic fistula and mortality.

Adult↗