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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synthetic porcine secretion was labelled by the conjugation-labelling method of Bolton & Hunter, the lactoperoxidase method, the gaseous diffusion method, and the chloramine-T method. The chloramine-T technique was adapted as routine method. Ten mug (3.27 nmol) peptide was reacted with 5 mCi of Na125I at a concentration of chloramine-T of 1.3 mmol/l. Synthetic secretin was suitable for labelling for at least eight months when stored as dry matter in nitrogen-filled glass ampoules. Purification and separation of labelled from unlabelled hormone was carried out by gel-permeation chromatography on Sephadex G-50 superfine. The labelled preparation had a specific radioactivity of 405 +/- 33 muCi/nmol (mean +/- SEM., n = 9) and was unable for six days. 6-tyrosyl-secretin took more iodine compared to porcine synthetic secretin but had lower immunoreactivity with all antisera tested.
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PMID:Preparation of 125I-labeled synthetic porcine secretin for radioimmunoassay. 1 92

Panhypopituitarism may be associated with spontaneous hypoglycemia and marked insulin sensitivity. Five children with both growth hormone (GH) and adrenocorticotrophin (ACTH) insufficiency were studied in three periods: a) on no therapy; b) during cortisone acetate; and c) during GH and cortisone acetate replacement. With total caloric restriction prior to therapy, all patients became hypoglycemic (109 +/- 18 leads to 37 +/- 3.5 mg/dl, mean +/- SEM) and ketonemic (beta-hydroxybutyrate 0.10 +/- 0.02 leads to 3.04 +/- 0.63 mM and acetoacetate 0.05 +/- .01 leads to 0.80 +/- 0.15 mM) within 30 hours. Glutamine and alanine concentrations fell with fasting (511 +/- 13 leads to 293 +/- 26 muM and 394 +/- 58 leads to 137 +/- 12 muM, respectively) but to levels lower than in normal children. However, only alanine was significantly lower (P less than 0.05). With cortisone plus GH therapy, fasting glycemia was improved (73 +/- 6 mg/dl) at 30 hours fasting and was associated with increased alanine and glutamine concentrations (206 +/- 28 muM and 448 +/- 40 muM, respectively) and less ketonemia (beta-hydroxybutyrate 1.13 +/- 0.39 mM). Cortisone therapy alone resulted in intermediate improvement of these values. Only combined therapy resulted in increased lactate and pyruvate concentrations, which fell to normal with fasting. Fasting urinary ammonia excretion was unchanged whereas urea nitrogen excretion decreased significantly with therapy. The responses to alanine infusions following each study period in one patient were normal. The glycemic response to iv glucose was similar during each study period; however, post-prandial and glucose-stimulated insulin responses were increased with cortisone and cortisone plus GH therapy. We suggest that the hypoglycemia observed in hypopituitary patients is a substrate-mediated phenomenon, and that cortisone and growth hormone replacement therapy improve fasting glucose homeostasis, increase circulating alanine and glutamine concentrations, and decrease hepatic gluconeogenesis. These effects may be mediated through an increase in fat catabolism.
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PMID:The role of growth hormone and cortisone on glucose and gluconeogenic substrate regulation in fasted hypopituitary children. 17 83

In attempts to find a drug more active than pilocarpine, the tertiary nitrogen derivative of carbachol, N-demethylated carbachol, was synthetized and tested on several autonomic nervous system preparations. N-Demethylated carbachol was active at muscarinic and nicotinic sites in vivo and in vitro. In superfusion studies, N-demethylated carbachol contracted the smooth muscle of the guinea pig ileum as well as skeletal muscles of frog recus abdominis and chick biventer cervicis. N-Demethylated carbachol decreased blood pressure in the rat, with an ED50 ("/- SEM) of 4.82 +/- 0.78 mg/kg. After close arterial injection to the cat superior cervical ganglion, N-demethylated carbachol elicited contractions of the nictitating membrane (ED50 of 1.68 +/- 0.24 mg/kg) that were not significantly affected by atropine. N-D-methylated carbachol stimulated salivation in dog Wharton duct preparations with an ED50 of 2.55 +/- 0.81 mg/kg. In contrast, pilocarpine had no effects on skeletal muscles in vitro, produced ganglionic effects blocked by atropine, had a prominent effect on salivation, and tended to elevate blood pressure.
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PMID:Pharmacological studies on N-demethylated carbachol. 30 56

21 patients with gastroenterological disease and indication for the use of intravenous nutrition received an elemental diet (ED) for 5-44 days. In 6 out of 8 patients with exacerbation of Crohn's disease remissions were achieved, apart from 3 persistent fistulas. In 5 out of 9 cases with various primary diseases and postoperative intestinal fistulas, spontaneous healing was observed. Furthermore, 2 patients with ulcerative colitis, 1 with radiation enteritis and 1 with pancreatitis were treated with ED. On ED, hemoglobin increased from 11.3 +/- 0.4 (m +/- SEM) to 12.0 +/- 0.5 g% (p less than 0.01) and serum albumin from 2.7 +/- 0.1 to 3.4 +/- 0.1 g% (p less than 0.001). Nitrogen requirements were studied in 11 patients receiving various quantities of ED. Nitrogen balance was found to be in equilibrium or positive in 7 patients, and negative in 4. In one patient with severe ulcerative colitis, fecal nitrogen losses were higher than urinary nitrogen losses. The unpleasant taste of ED resulting from free amino acids limited the ED supply in 3 patients and led to premature ending of ED administration in 3 other patients. In such cases ED may be given by nasogastric tube feeding. From the results presented it appears that ED is indicated in Crohn's disease and intestinal fistulas. However, the results obtained require confirmation by further observations and comparison with an intravenously fed control group.
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PMID:[Elementary diet as an alternative to parenteral feeding in severe gastrointestinal diseases]. 40 20

The structure of nitrogen-fixing nodules produced by Rhizobium infection of the non-legume Parasponia andersonii was examined by light and electron (both SEM and TEM) microscopy. Comparisons were made with the nodules previously described on P. rugosa. Like the nodules on different non-legumes formed by other types of endophytes, the Rhizobium nodules on Parasponia resembled modified roots by having a central vascular bundle surrounded by an endophyte-infected zone. The intimate association between the Rhizobium and the host nodule cell was compared with the Rhizobium association found in legumes. The rhizobia were not released from the infection thread as happens in the legume. The infection thread, which propagates the Rhizobium infection to new cells, was transformed within a nodule cell from a darkly stained (light microscopy) or very electron-dense (TEM) structure to a number of thread types. The walls of the threads varied greatly in thickness and often the thread structures were without rigid walls and were only enclosed by a plasma membrane. If the rhizobia are transformed into bacteroids, as in the legumes, it would have to occur when the threads had reached their mature size, when bacterial division had ceased. Nitrogen fixation was considered to occur in all thread types.
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PMID:Structure of nitrogen-fixing nodules formed by Rhizobium on roots of Parasponia andersonii Planch. 47 39

Plastic coverslips made of polymethylpentene serve as excellent substrates for growth of bovine endothelial cells, and are easily processed for both transmission (TEM) and scanning (SEM) electron microscopy. Portions of the same coverslip (monolayer) are used for both SEM and TEM examination and are fixed, postfixed, and dehydrated as a single entity. The portion of the coverslip for SEM is then excised, critical point dried, and mounted for sputter coating prior to viewing. The remaining piece of coverslip used for TEM is Epon-Araldite embedded, polymerized, separated from the coverslip by liquid nitrogen immersion, and sectioned either "en face" or in cross section for viewing. Coated glass coverslips are not required and organic solvents such as propylene oxide, acetone, and amyl acetate can be used for dehydration and infiltration. Furthermore, specimens do not require re-embedding or blocks to be glued onto blank capsules before sectioning. The number of cells needed to achieve a monolayer is significantly reduced compared to the usual culture flasks, but are abundant enough to assess ultrastructural changes accurately. Support films may be required to prevent folding of the ultrathin section which can obstruct viewing of cells located on the edge of the section.
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PMID:Transmission and scanning electron microscopy of cell monolayers grown on polymethylpentene coverslips. 49 32

Since large volumes of nutrient rich amniotic fluid are swallowed by the fetus, it has been suggested that intestinal digestion and absorption contribute significantly to fetal nutrition. To see if nutrients are being gained across the intestine, we measured blood flow and intestinal arteriovenous concentration differences of glucose, alpha-amino nitrogen, lactate, fructose and oxygen in eleven third trimester fetal sheep with chronically implanted vascular catheters. We found that in fetal blood circulating through the intestine nutrient concentration decreased significantly with arterio-venous concentration differences for glucose of 0.78 +/- 0.21 (SEM) mg/dl (P < 0.002), for alpha-amino nitrogen of 0.52 +/- 0.15 mg/dl (P < 0.005), for lactate of 0.68 +/- 0.24 mg/dl (P < 0.05) and for oxygen of 1.50 +/- 0.08 ml/dl (P < 0.001). Fructose concentration did not change. Blood flow to the fetal intestine averaged 89.92 +/- 7.16 ml/min and the intestine consumed 0.74 +/- 0.24 mg of glucose, 0.43 +/- 0.17 mg of alpha-amino nitrogen, 0.83 +/- 0.28 mg of lactate and 1.37 +/- 0.14 ml of oxygen per minute. Compared to previously published values for the umbilical uptake of nutrients the fetal intestine metabolizes about 4% of the glucose, 6% of the alpha-amino nitrogen, 13% of the lactate and 6% of the oxygen obtained across the umbilical circulation. Intestinal absorption does not appear to serve as a source of simple nutrients for the rest of the fetus, in fact intestinal metabolism extracts significant amounts of nutrients from fetal blood.
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PMID:Consumption of carbohydrates, amino acids and oxygen across the intestinal circulation in the fetal sheep. 55 Nov 16

To study the effect of lung expansion at birth on surfactant secretion, we delivered by hysterotomy 11 litters of rabbit pups at 30 days of gestation and divided them into three groups that were killed: 1) after 30 min air-breathing, 2) after 30 min nitrogen-breathing, and 3) after 30 min tracheal occlusion. Each group was compared to a littermate group killed at birth. Groups 2) and 3) continued respiratory efforts for 30 min despite progressive asphyxia. Six additional litters were pretreated with atropine; at delivery one-half of each litter was killed, the remaining pups were subjected to 30 min of hypoxic gas breathing. After sacrifice, alveolar surfactant was recovered by saline lavage and estimated quantitatively on a surface-tension balance. Surfactant concentration at birth was 1.40 +/- 0.22 mg/g dry lung and increased to 1.86 +/- 0.19 (+/- SEM) after 30 min air-breathing (P less than 0.01). Also, surfactant was increased in the nitrogen-breathing pups (from 1.61 +/- 0.35 in littermate controls to 2.41 +/- 0.58; P less than 0.03), but not to a significant degree in the occluded group (1.34 +/- 0.33 vs. 1.41 +/- 0.28), or the atropine pretreated breathing pups (1.77 +/- 0.29 vs. 1.89 +/- 0.25).
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PMID:Augmentation of pulmonary surfactant secretion by lung expansion at birth. 58 65

The role of angiotensin II in the pulmonary vasoconstriction induced by alveolar hypoxia was investigated with the competitive inhibitor of angiotensin, saralasin acetate. Unilateral alveolar hypoxia was induced in dogs by ventilation of one lung with 100% N2 through a double lumened endotracheal cannula while maintaining adequate systemic oxygenation by ventilating the other lung with 1oo% O2. Pulmonary perfusion was monitored with 133Xe and external detectors. In 8 dogs perfusion to the test lung on room air before N2 ventilation was 49.2% (SEM +/- 3.8) of total lung perfusion. After 7 min of nitrogen ventilation, perfusion to that lung was 35.6% (SEM +/- 2.9) of cardiac output (P less than 0.001), a reduction of 27.5% (SEM +/- 2.4). After infusion of 6--24 microgram.kg-1/min of saralasin acetate, beginning 2 min before the alveolar hypoxic challenge and continuing through it, unilateral alveolar hypoxia continued to reduce perfusion to that lung by 28.8% (P = 0.6 from control). In 2 dogs a higher infusion of 60 microgram.kg-1/min failed to reduce the alveolar hypoxic vasoconstriction and in 2 dogs a 15 min infusion of 6 microgram.kg-1 of saralasin acetate before alveolar hypoxia and continuing through it, still failed to inhibit alveolar hypoxic vasoconstriction. Thus, no role was demonstrated for angiotensin II in acute alveolar hypoxic vasoconstriction of the dog.
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PMID:Failure of saralasin acetate, a competitive inhibitor of angiotensin II, to diminish alveolar hypoxic vasoconstriction in the dog. 60 79

A chamber for introducing, fracturing and coating frozen biological samples has been developed as an attachment to the sepcimen chamber of a scanning electron microscope. Together with a eucentric-tilt cold-stage, this chamber constitutes a complete system for viewing fractured biological surfaces of the type normally only seen by replica techniques. An air-lock on the chamber accepts a transfer module to allow insertion of the frozen sample without frost build-up. Fracturing is carried out with a precisely adjustable cooled knife under a 10--100X binocular microscope. The sample can tilt and rotate while being coated with carbon or metals evaporated from rechargeable sources introduced through the air-lock. Cooling in the chamber is provided by a cylindrical copper tank filled with liquid nitrogen. The chamber has its own LN2 trapped high vacuum system. After preparation the sample can be placed directly into the SEM through an isolation valve. The cold-stage utilizes a Joule-Thomson refrigerator. The sample can be kept below 103 K at all times though there are provisions for heating it in the fracturing and cold-stage positions. A system of controls, sensors and interlocks simplifies the operation of the system.
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PMID:A chamber attached to the SEM for fracturing and coating frozen biological samples. 65 Jun 76


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