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Biomedical subjects

R Gross

Publications and source records attributed to R Gross.

At least 199 records · Page 11Linked to original sources
PubMed1995

Alterations of insulin response to different beta cell secretagogues and pancreatic vascular resistance induced by N omega-nitro-L-arginine methyl ester.

1. We studied a possible interplay of pancreatic NO synthase activity on insulin secretion induced by different beta cell secretagogues and also on pancreatic vascular bed resistance. 2. This study was performed in the isolated perfused pancreas of the rat. Blockage of NO synthase was achieved with Nw-nitro-L-arginine methyl ester (L-NAME); The specificity of the antagonist was checked by using its D-enantiomer as well as by substitutive treatments with sodium nitroprusside (SNP) as a NO donor in studies of glucose-induced insulin secretion. 3. Arginine (5 mM) induced a monophasic response which was, in the presence of L-NAME at equimolar concentration, very strongly potentiated and converted into a 13 times higher biphasic one. D-NAME (5 mM) was only able to induce a 3 times higher response, but provoked a similar vasoconstrictor effect. 4. The small biphasic insulin secretion induced by L-leucine (5 mM) was also strongly enhanced, by 8 times, in the presence of L-NAME (5 mM) vs 2 times in the presence of D-NAME (5 mM). 5. beta cell responses to KCl (5 mM) and tolbutamide (0.185 mM) were only slight increased by L-NAME (5 mM) to values not far from the sum of the effects of L-NAME and of the two drugs alone. D-NAME (5 mM) was totally ineffective on the actions of both secretagogues. 6. L-NAME, infused 15 min before and during a rise in glucose concentration from 5 to 11 mM, was able in the low millimolar range (0.1-0.5 mM) to blunt the classical biphasic pattern of beta cell response to glucose and, at 5 mM, to convert it into a significantly greater monophasic one. In contrast, D-NAME (5 mM) was unable to induce similar effects. 7. SNP alone at 3 microM was ineffective but at 30 microM substantially reduced to second phase of insulin response to glucose; however, at both concentrations the NO donor partly reversed alterations in insulin secretion caused by L-NAME (5 mM) and restored a biphasic response.

Analysis of Variance↗
PubMed1995

Urban nutrition in developing countries.

In developing countries, the past decades have seen a marked demographic shift from rural to urban. By the year 2000, 40% of the population of the Third World will live in urban areas. We have limited specific knowledge of the similarities and differences in diet, nutrition status, and health effects of diet and lifestyle between the traditional rural populations and the emerging urban poor. Such information will be useful for basic descriptive information as well as for assistance in the design and execution of health and nutrition projects for the urban poor.

Child↗
PubMed1995

Biological activity of immunoreactive insulin-like activity extracted from rat submandibular gland.

Earlier studies indicate the presence of an insulin-like immunoreactivity (ILI) in rat submandibular salivary glands (SSG). Previous observations also showed that streptozotocin (STZ)-induced diabetes was accompanied by an increase in SSG ILI concentrations. In the present work we studied the effect of SSG ILI from normal and STZ diabetic rats (ILI-N and ILI-D, respectively) on insulin receptor binding and function in LMH cell line. ILI-N and ILI-D inhibited 125I-insulin binding to intact cells and wheat germ agglutinin (WGA)-purified insulin receptors with a high affinity. Furthermore, ILI-N and ILI-D activated, although weakly, the beta-subunit autophosphorylation of solubilized and WGA-purified insulin receptors. An ATP hydrolytic activity was present in ILI-N and, to a greater extent, in ILI-D extracts, which can at least in part explain their low potency for activating autophosphorylation and kinase activity of insulin receptors in vitro. However, after ILI treatment of intact cells and immunoprecipitation of insulin receptors, ILI induced a dose-dependent tyrosine phosphorylation of the insulin receptor beta-subunit. Finally, ILI-N and ILI-D stimulated amino acid uptake and lipogenesis in LMH cells. These findings suggest that SSG ILI is biologically active and can participate in metabolic regulations.

Amino Acids↗
PubMed1995

Analysis of breakthrough pain in 50 patients treated with intrathecal morphine infusion therapy. Development of tolerance or infusion system malfunction.

Fifty patients with intractable benign pain were treated with intrathecal morphine (IT-MS) infusion therapy. Median follow-up was 39 months (range 5-70). Breakthrough pain was reported in 45 (90%) patients in 75 outpatient clinic events. A diagnostic algorithm was developed to evaluate and efficiently treat these patients. A programmed bolus (50% of daily dose) identified that 50 (67%) breakthrough events where due to partial tolerance to the IT-MS. Radiographic survey of the catheters identified malfunctions in 11 patients. Attempts to withdraw CSF from the side-port demonstrated obstruction in 7 due to kinking not seen on X-rays. Side-port myelography demonstrated scarring that obstructed the flow of morphine to the spinal cord in 2 patients. Benefits were regained after all surgical catheter corrections. In total, partial tolerance was seen in 23 patients (46%) during 50 (67%) breakthrough events, 15 patients (30%) required 22 catheter revisions during 27% of breakthrough events and 2 patients had progressive disease. True tolerance was encountered in only 5 patients (10%) during 5 (7%) breakthrough pain events.

Adult↗
PubMed1995

[Assessment by the primary care physician of his influence on the patient's hospital choice and of his own ability to evaluate hospital quality].

We report a mail survey (1993) of 677 primary care physicians employed by Israel's 4 sick funds of their influence on the patient's choice of hospital. In the light of the far-reaching changes currently taking place in the health system in Israel, factors considered by physicians in recommending a hospital were studied. About 50% reported having a high degree of influence over patient choice of hospital for elective procedures. Most reported themselves able to evaluate the quality of hospital care, especially results of clinical treatment (89%). Multivariate analysis revealed the physicians who reported a high degree of influence on patient hospital choice were men under the age of 65, independently employed by a smaller sick fund or by several sick funds. They considered themselves capable of evaluating hospital quality and were in regular professional contact with at least 1 hospital. The main factors considered in recommending a hospital were quality of its physicians and medical care, the way in which the hospital staff related to patients, and the level of equipment and technology available. Little importance was given to sick fund hospitalization policy. The survey findings had implications for primary care physicians, and for policymakers of the sick funds and the government.

Choice Behavior↗
PubMed1994

Identification and characterization of two functional domains of the hemolysin translocator protein HlyD.

Secretion of Escherichia coli hemolysin is mediated by a sec-independent pathway which requires the products of at least three genes, hlyB, hlyD and tolC. Two regions of HlyD were studied. The first region (region A), consisting of the 33-amino acid, C-terminal part of the HlyD protein, is predicted to form a potential helix-loop-helix structure. This sequence is conserved among HlyD analogues of similar transport systems of other bacterial species. Using site-directed mutagenesis, we showed that the amino acids Leu475, Glu477 and Arg478 of this region are essential for HlyD function. The last amino acid of HlyD, Arg478, is possibly involved in the release of the HlyA protein, since cells bearing a hlyD gene mutant at this position produce similar amounts of HlyA to the wild-type strain, but most of the protein remains cell-associated. Competition experiments between wild-type and mutant HlyD proteins indicate that region A interacts directly with a component of the secretion apparatus. The second region of HlyD (region B), located between amino acids Leu127 and Leu170, is highly homologous to the otherwise unrelated outer membrane protein TolC. Deletion of this region abolishes secretion of hemolysin. This sequence of HlyD also seems to interact with a component of the hemolysin secretion machinery since a hybrid HlyD protein carrying the corresponding TolC sequence, although inactive in the transport of HlyA, is able to displace wild-type HlyD from the secretion apparatus.

Amino Acid Sequence↗
PubMed1994

[Laparoscopic cholecystectomy using the Hasson trocar].

Laparoscopic cholecystectomy has become the standard operation for symptomatic gallstone disease. There is general agreement that the advantages of this procedure in selected patients outweigh those of conventional open cholecystectomy. However, technical aspects of the procedure may expose the patient to severe and even lethal complications, such as bowel or bladder perforation or injury to major blood vessels. In our opinion these complications are avoided by the routine use of the blunt-tipped Hasson trocar, introduced through a 2 cm infra-umbilical incision in an open laparoscopic technique. We have used it successfully in 120 consecutive patients and believe it to be the procedure of choice for laparoscopic cholecystectomy.

Cholecystectomy, Laparoscopic↗
PubMed1994

Effects of imidazolines and derivatives on insulin secretion and vascular resistance in perfused rat pancreas.

The effects of imidazolines and derivatives were studied on insulin secretion and vascular resistance in the isolated perfused rat pancreas. On insulin secretion, two imidazoline alpha 2-adrenoceptor antagonists, efaroxan (1-100 microM) and RX821002 (10 microM), had a stimulating response; however, idazoxan, like the non-imidazoline alpha 2-adrenoceptor antagonist yohimbine, was ineffective at 10 microM. The oxazoline rilmenidine with alpha 2-adrenergic activity at 10 microM), an imidazoline devoid of alpha 2-adrenergic activity, also had an insulin-releasing effect. On pancreatic vessels, all imidazolines tested (efaroxan, RX821002, antazoline and idazoxan), in contrast to yohimbine, induced vasoconstriction. Rilmenidine did not have a vasoconstrictor effect after blockade of alpha 2-adrenoceptors. Furthermore, the efaroxan-induced insulin release or vasoconstriction was not affected by the blockade of alpha 2- and alpha 1-adrenoceptors. This study shows that imidazolines and derivatives are able to stimulate insulin release and induce vasoconstriction in the rat pancreas. These effects cannot be ascribed to an interaction with alpha-adrenoceptors but may involve different types of imidazoline sites.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1994

Presence of infective Epstein-Barr virus in the urine of patients with infectious mononucleosis.

The presence of Epstein-Barr virus (EBV) in the blood and urine of 20 patients with infectious mononucleosis (IM) was investigated together with the clinical course of the disease, and in 9 patients up to 2-7 months after recovery. EBV DNA, analyzed by the polymerase chain reaction (PCR), was detected in the blood of all 20 patients from the first sample obtained and detected between 3 to 42 days from the beginning of symptoms and up to 2-3 months after recovery. In the urine, EBV DNA was detected in 15 out of 16 (93%) patients in the first sample obtained and detected between 3 to 50 days during the clinical course of the disease. In four patients EBV DNA was detected in the urine up to 3 months after full recovery. Seventeen out of 26 (65%) urine samples including 3 which were obtained 2-7 months after recovery infected B cells as assessed by PCR. Nine out of 12 (75%) urine samples tested induced Epstein-Barr nuclear antigen (EBNA) in the infected B-cell line. In addition to the persistence of EBV in the blood of IM patients, these studies show for the first time the presence of infective EBV in the urine during the clinical course of the disease and up to 7 months after full clinical recovery.

Antigens, Viral↗