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Biomedical subjects

J Ryan

Publications and source records attributed to J Ryan.

At least 289 records · Page 16Linked to original sources
PubMed1981

Somatostatin in human pancreatic and gastric juice.

Considerable amounts of IRS are secreted after secretin injection in human pancreatic juice collected during endoscopic retrograde cholangiopancreatography. The mean IRS levels in the pancreatic juice of non-diabetic patients were 79 +/- 10 (SE) pg/ml. The IRS levels in NIDDM were considerably higher, the mean value being 1635 +/- 313 (SE) pg/ml. The mean IRS level in IDDM were 312 +/- 151 (SE) pg/ml. In IDDM, those patients whose blood glucose levels were well controlled by insulin showed low pancreatic juice IRS ranging from non-detectable to 46 pg/ml. On the other hand, those with uncontrolled hyperglycemia showed IRS levels ranging form 452 to 1047 pg/ml. Gel-filtration profiles of IRS in pancreatic juice extracts were not consistent in all cases. Some showed IRS peaks eluting with SS14 and SS28, while others contained IRS species that were eluted in more retarded fractions. The retarded IRS fraction exhibited biological activity indistinguishable from that of SS14 as indexed using a quantitative cytochemical method.

Chromatography, Gel↗
PubMed1981

Immunoreactive somatostatin in human pancreatic secretion.

Somatostatin in human pancreatic juice collected during endoscopic retrograde cholangiopancreatography following secretin injection was determined by RIA. The mean immunoreactive somatostatin (IRS) levels in the pancreatic juice of 13 non-diabetics was 78 +/- 11 (SE) pg/ml. The IRS levels in 4 non-insulin-dependent diabetics ranged from 843 to 2286 pg/ml with a mean of 1559 +/- 392 (SE) pg/ml. This was significantly greater than non-diabetic values. The IRS in the pancreatic juice was immunologically indistinguishable from somatostatin14 but consisted of 2 major components, one corresponding to somatostatin14 and the other being of a molecular size of approximately 3000 daltons.

Adult↗
PubMed1981

The effect of glucocorticoids on the insulin receptor: an in vivo and in vitro study.

We have studied the effect of glucocorticoid exposure on the insulin receptor of short term cultures of human lymphocytes (IM-9 cells) and the effect of short term administration of these agents to normal volunteers. When cultured human lymphocytes were exposed to 10(-5) M hydrocortisone for 18 h at 37 C, insulin binding increased due to an increase in the number of receptors per cell. The effect had appropriate specificity in terms of concentration and type of steroid used. By contrast, hGH binding to these cells was decreased under similar circumstances of incubation, due to a decrease in the number of hGH receptors per cell. When prednisone (40 mg/day) was given to normal subjects for 3 days, a moderate state of insulin resistance was induced characterized by a modest increase in blood glucose and a more pronounced increase in plasma insulin concentration. Under these circumstances there was no change in tracer insulin binding to peripheral monocytes nor changes in the concentration of insulin necessary to inhibit binding by 50%, the number of receptors per cell or the affinity of the receptor. We conclude that glucocorticoids increase insulin binding in vitro in cultured human lymphocytes but that competing influences in vivo such as increasing circulating insulin concentration, redistribution of cell types in the circulation, and possibly other influences prevent these changes from occurring in circulating monocytes. These findings emphasize the complexity of studying the effects of pharmacological agents on hormone binding.

Blood Glucose↗
PubMed1980

Alanine transport by Chinese hamster ovary cells with altered phospholipid acyl chain composition.

The Na+-dependent transport of alanine has been examined in Chinese hamster ovary (CHO) cells as a function of the fatty acid composition of their membrane lipids. Significant changes in the fatty acid composition of the CHO cell phospholipids were achieved by supplementation of the growth medium with specific saturated (palmitate) or monoenoic (oleate) free fatty acids. Arrhenius plots of the temperature-dependent uptake of alanine were constructed for cells of altered fatty acid composition. Alanine uptake was characterized by a single discontinuity in the Arrhenius plot. The temperature of this break was observed to be dependent upon the fatty acid composition of the cell phospholipids, ranging from 16 degrees C for cells enriched with oleate to 32 degrees C for cells enriched in palmitate. Calculation of the Km value for the uptake process showed no significant change with temperature or fatty acid supplementation. Correlations are made between the physical state of the membrane lipids and the temperature-dependence for alanine transport. The results are discussed in terms of membrane fatty acid composition, ordered in equilibrium fluid phase transitions and amino acid transport.

Adenosine Triphosphatases↗
PubMed1980

Cerebroarthrodigital syndrome: a newly recognized formal genesis syndrome in three patients with apparent arthromyodysplasia and sacral agenesis, brain malformation and digital hypoplasia.

We describe three patients with a complex syndrome of apparent arthromyodysplasia, dyscephaly, sacral agenesis, and hypoplastic digitis. Cause is unknown, but an environmental cause is suspected on the basis of ergotamine exposure in one case and diazoxide intake in another, together with suggestive similarities to anomalies seen in animals treated with these drugs and to calves with the Australian hydranencephaly/arthrogryposis syndrome caused by Akebane or Aino virus. Pathogenetically the primary defect may be a neural tube-neural crest dysplasia with multiple secondary and tertiary manifestations and deformities.

Arthrogryposis↗
PubMed1980

Positron emission tomography for the evaluation of pancreatic disease.

Efficient techniques for native-labeling of amino acids have been combined successfully with emission tomography to yield significant improvements in pancreatic imaging. Carbon-11-labeled tryptophan appears to be the best agent available currently for imaging the pancreas. Optimum scanning times begin 30 min after tracer administration. Positron emission tomography with 11C-tryptophan is capable of defining both morphological and functional alterations in the pancreas. Tumors as small as 2 cm in diameter can be detected, but reliable differentiation of pancreatic cancer from pancreatis may not be possible even with this improved imaging technique. Longitudinal multiplane emission tomography in single-photon mode with the Pho/Con provides an efficient and satisfactory approach to pancreatic imaging with the positron-emitting radiopharmaceuticals.

Carbon Radioisotopes↗
PubMed1979

Impact of new diagnostic imaging methods on pancreatic angiography.

The results of 100 consecutive pancreatic arteriograms performed in concert with a combination of other diagnostic procedures (gray scale ultrasonography, computed tomography, endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography) were evaluated to determine the value of angiography in diagnosis and management of patients with known or suspected pancreatic disease. Angiography was found to be valuable for diagnosis in 68% (68/100) of cases and was considered helpful for management in 81% (57/70) of patients with pancreatic neoplasm, pancreatitis, or a nonpancreatic abnormality.

Angiography↗
PubMed1979

Hepatic clearance mechanism of Tc-99m-HIDA and its effect on quantitation of hepatobiliary function: Concise communication.

Parameters affecting the hepatobiliary clearance of Tc-99m N(2,6-dimethylphenyl carbamoylmethyl) iminodiacetic acid (Tc-HIDA) were evaluated in dogs. Competitive clearance studies, were performed with Tc-HIDA after infusion to plasma saturation levels of an anion, sodium sulfobromophthalein (BSP), and a cation, oxyphenonium. The results demonstrated that Tc-HIDA is transported through hepatocytes by a carrier-mediated organic-anion pathway. The data are consistent with an alteration of the elimination kinetics of Tc-HIDA induced by elevations in the serum bilirubin level, and it is predicted that serum bilirubin at some increased concentration will dominate the distribution and elimination kinetics of Tc-HIDA independently of hepatobiliary status. A quantitative description of liver function in terms of regional distribution and elimination rate constants will require either a pharmacokinetic model that expressly includes the effects of bilirubin, the development of new anionic hepatobiliary agents capable of displacing endogenous bilirubin from transport binding sites, or the development of new hepatobiliary agents that use a different clearance mechanism from that used by bilirubin.

Animals↗
PubMed1979

Apathy in nursing.

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Attitude of Health Personnel↗
PubMed1977

Early detection of breast cancer.

One thousand referred patients with breast symptoms, a history of breast disease, or a family history of breast carcinoma have been examined at a suburban breast clinic. This is a preliminary survey of the data and results so far obtained from the initial examination of these patients. The examination consisted of history-taking by means of a questionnaire, physical examination of the breasts, thermography and xeromammography. A report correlating the findings was forwarded to the referring doctor in each case and any necessary action was indicated in the report. Seventy-eight patients were thought to require biopsy of a suspicious lump or mammographic lesion (7.8% of the total number); 76 patients actually had biopsies, and 18 patients were found to have carcinoma of the breast (23.8% of the total number of patients who had biopsies). The overall incidence of carcinoma in the 1000 women attending the clinic was 1.8% at the initial visit. While general population screening for breast carcinoma may be hard to justify, from both the detection rate and an economic point of view, it would appear from our experience to date that screening of selected high-risk referred patients is justified and, in fact, desirable.

Adenocarcinoma↗
PubMed1977

Formation of adenosine 5'-phosphoroglycerol from ATP and glycerol by rat liver plasma membranes.

Rat liver plasma membranes are shown to catalyze the formation of adenosine 5'-phosphoroglycerol and adenosine 5'-phosphoromethanol from ATP and glycerol or methanol, respectively. In the presence of 2.7 M glycerol and 1 mM ATP, 30 nmol of adenosine 5'-phosphoroglycerol were formed in 10 min per mg of rat liver plasma membranes. The structures of these phosphodiesters were determined from the following evidence. Radioactivity was incorporated into the nucleotide from [alpha-32P]ATP, [2,8-3H]ATP, or [2-3H]glycerol. Treatment with snake venom phosphodiesterase I converted the nucleotides to AMP. The compound formed from glycerol and ATP co-migrated with adenosine 5'-phosphoroglycerol synthesized from glycerol and adenosine 5'-phosphoromorpholidate in five thin layer chromatography systems. The methyl derivative co-migrated with adenosine 5'-phosphoromethanol synthesized from methanol and adenosine 5'-phosphormorpholidate in several thin layer chromatography systems. The synthesis of these phosphodiesters was also catalyzed by chicken embryo fibroblast membranes and solubilized rat liver plasma membranes but not by rat heart plasma membrane preparations. Formation of significant amounts of these phosphodiesters required relatively high concentrations of the alcohols (greater than 1 M). The alcohol concentration dependence did not exhibit substrate saturation at physiologically meaningful concentrations of glycerol or methacol. It is proposed that either the alcohols examined were not the natural substrates for this enzyme or that the alcohol/AMP phosphodiesters were formed as a result of trapping of an enzyme/nucleotide intermediate. Adenosine 5'-phosphoroglycerol formation was inhibited approximately 50% by 15 mM NaF. Epinephrine, norepinephrine, glucagon, and prostaglandin E1 were without effect. Alloxan, an inhibitor of adenylate cyclase did not inhibit formation of adenosine 5'-phosphoroglycerol. It is concluded that adenylate cyclase was not responsible for formation of these phosphodiesters. The physiological significance of this reaction remains undefined.

Adenosine Triphosphate↗