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Biomedical subjects

A Fernandez

Publications and source records attributed to A Fernandez.

At least 235 records · Page 13Linked to original sources
PubMed1988

Angiotensin converting enzyme in brush-border membranes of avian small intestine.

Angiotensin converting enzyme activity was identified in brush-border membranes purified from the small intestinal epithelium of the common grackle, Quiscalus quiscula. Angiotensin converting enzyme was enriched 20-fold in the membrane preparation, compared with intestinal epithelial cell scrapes, and was coenriched with the brush-border markers, alkaline phosphatase and aminopeptidase N. The kinetics of hydrolysis of N-[3-(2-furyl)acryloyl]-L-phenylalanylglycylglycine (FAPGG) gave a Vmax of 907 +/- 41 units g-1 and a Km of 55 +/- 6 mumol l-1. The avian intestinal angiotensin converting enzyme was inhibited by the antihypertensive drug, Ramipril, with a median inhibitory concentration (IC50) of 1 nmol l-1. In the light of previous studies on angiotensin converting enzyme in mammalian epithelia, these results may implicate a physiological role for angiotensin converting enzyme in regulating electrolyte and fluid uptake in bird small intestines.

Animals↗
PubMed1987

Dipeptidyl peptidase-II activity in cultured astroglial cells from neonatal rat brain.

Astrocytic glial cells in primary culture from neonatal rat brain possess prominent dipeptidyl peptidase-II activity. This enzyme has been previously isolated and purified from whole brain tissue. The glial enzyme characteristically hydrolyzed glycyl-proline-p-nitroanilide (GPN) substrate to release glycyl-proline dipeptide plus p-nitroaniline products. At the enzyme's optimal pH of 5.4, the activities of other tested amino exopeptidases were virtually zero. At pH greater than 8, activity was less than 2% of the activity at pH 5.4, which suggested a paucity of the related enzyme, dipeptidyl peptidase-IV. No competitive inhibition was observed for glycine, proline nor their permuted dipeptides. Glial dipeptidyl peptidase-II activity was strongly inhibited by Hg2+, while other redox sulfhydryl agents were ineffective. Tested cations did not affect activity, except K+ which was mildly inhibitory. Chelating agents were not inhibitory. Of the peptidase inhibitors tested, only phenylmethylsulfonyl fluoride and puromycin were partially inhibitory. We suggest that dipeptidyl peptidase-II may play a role in glial processing of brain peptides which possess an N-terminal penultimate proline residue.

Animals↗
PubMed1987

Regulation of membrane turnover by ras proteins.

Because ras oncogenes mediate abnormal cellular growth, ras proteins have been presumed to play a role primarily in growth control. The biological function of ras proteins may, however, prove to be much more diverse: ras proteins may be involved in cellular functions that control endocytosis and/or exocytosis.

Cell Membrane↗
PubMed1987

Differential gallbladder contractility in fundal adenomyomatosis: demonstration by cholecystokinin cholescintigraphy.

The cholecystokinin cholescintigraphic findings of fundal adenomyomatosis in a 29-yr-old male with severe post-prandial pain are presented. Planar cholescintigraphy demonstrated a trilobed gallbladder contour. Following the administration of 0.02 micrograms/kg of cholecystokinin at maximal gallbladder filling, fundal dyskinesia was observed. Regional gallbladder ejection fractions were: whole gallbladder, 43%; proximal two-thirds of the gallbladder, 70%; and gallbladder fundus, 32%. First harmonic Fourier phase and amplitude images demonstrated: (a) decreased fundal amplitude values, and (b) a phase shift of the pixels in the gallbladder fundus.

Adult↗
PubMed1985

Nausea, vomiting, and abdominal pain after Roux-en-Y anastomosis: motility of the jejunal limb.

The Roux-en-Y anastomosis is a surgical procedure performed to divert the pancreaticobiliary juices from the gastric pouch in patients who have alkaline reflux gastritis or esophagitis, or both, that develop after vagotomy and Billroth I or II operations. After the Roux-en-Y procedure the inflammation subsides but is often replaced by a characteristic group of symptoms--chronic abdominal pain, nausea, and vomiting worsened by eating. Using a semiconductor recording probe, we investigated the Roux limb in 7 subjects who were fasted and then fed (liquid and solid meals). In the fasted state the migrating motor complex was either completely absent or grossly disrupted. Only 1 subject converted to a fed-state motility pattern in the Roux limb after a liquid meal (Osmolite), and all 7 subjects failed to convert to a fed state after a solid meal. These studies suggest that the Roux-en-Y syndrome of pain, nausea, and vomiting is secondary to a defect in motor function and that the Roux limb is acting as an area of functional obstruction.

Adult↗
PubMed1985

Simultaneous ipsilateral trochanteric and femoral shaft fracture.

Thirteen cases of concomitant trochanteric and shaft fracture of the same femur are reported. The hip fracture was initially missed in two cases. Osteosynthesis of both fractures was performed in ten cases. Both fractures healed in the 12 cases followed for 6 months or more. Osteosynthesis of both fractures is recommended, preferably by fixation with angled or straight plates, and Ender nailing in selected cases.

Accidents, Traffic↗
PubMed1984

Purified Shigella enterotoxin does not alter intestinal motility.

A purified Shigella enterotoxin (pST) and a cell-free lysate with pST removed (CFL-pST) from the whole-cell lysate of Shigella dysenteriae 60 R were used to study their effect on the myoelectric activity and mucosal integrity of rabbit ileal segments. We have previously defined two myoelectric patterns: the migrating action potential complex and repetitive bursts of action potentials that occur in response to certain bacteria and their enterotoxins. The in vivo model consisted of isolated ileal segments in male New Zealand White rabbits. The segments were infused with sterile saline (1 ml/h), pST (2.4-micrograms injection), or CFL-pST (1 ml/h). Myoelectric activity in the segments exposed to pST was similar to that with the saline infusion, but CFL-pST induced significant alterations in myoelectric activity in the form of repetitive bursts of action potentials. The mucosa of the segments exposed to pST showed only mild inflammatory changes. In contrast, CFL-pST caused moderate to severe inflammatory changes with enterocyte necrosis. These studies show that pST, a known enterotoxin, did not alter myoelectric activity and had no significant effect on the integrity of ileal mucosa, as determined by light microscopy. CFL-pST caused both inflammation and tissue necrosis with significant alterations in motor activity. These studies suggest that S. dysenteriae 60 R produces a substance or substances other than pST that cause florid in vivo cytotoxicity and alter myoelectric activity.

Action Potentials↗
PubMed1983

Wound healing. Helping a natural process.

Wound healing calls for little outside interference. All the physician need do is ensure that the wound is clean and debrided and decide whether closure by suture or by granulation tissue formation is indicated. Suture repair should be delayed if the wound is heavily contaminated. Use of skin tapes or of constant-pressure garments may enhance results.

Anti-Bacterial Agents↗