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Biomedical subjects

A Aly

Publications and source records attributed to A Aly.

At least 37 records · Page 2Linked to original sources
PubMed1992

Role of immersion refractometry for investigating laser-induced effects in cells.

The broad background of scattered light observed in spectra of cell suspensions is reduced by factors of up to 20 by immersion refractometry allowing for improved spectroscopic determination of the absorption properties of cells in the 325-820 nm range. Refractive-index matched spectra of E. coli C1a exhibit a set of resonant features near 422, 561, and 582 nm. Exposure wavelengths are chosen based on this spectrum and cell viability is investigated in E. coli suspensions exposed to 350, 400, 422, 440, and 700 nm radiation delivered in nanosecond pulses with total doses from 500 millijoules to 60 Joules. We observe a loss in cell viability for doses greater than 1 Joule at 422 nm and for all doses at other wavelengths; exposures of less than 1 Joule at 422 nm enhance growth. Excluding exposures at wavelengths within the resonant feature, longer wavelengths are less effective at reducing the viability of E. coli C1a. This indicates the occurrence of at least two absorption processes.

Absorption↗
PubMed1991

Aspects on the role of tachykinins and vasoactive intestinal polypeptide in control of secretion, motility and blood flow in the gut.

Both intrinsic and extrinsic neurons of the gut respond to mechanical and chemical stimuli by the release of neurotransmitters. We summarize here some of our recent work on the role of vasoactive intestinal polypeptide (VIP), substance P (SP) and neurokinin A (NKA) in the secretory, motor and vascular effects of hydrochloric acid stimulation in the isolated rat duodenal loop and electrical nerve stimulation and mechanical stimulation of the cat colon. Isolated duodenal loops of conscious rats were perfused with isotonic saline, and challenged at hourly intervals with brief exposures to increasing concentrations of HCL. The concentrations of bicarbonate and prostaglandin E2 (PGE2) released from the duodenal mucosa were significantly augmented already by pH 5.0 whereas VIP was significantly augmented at pH 3.0 and the tachykinins SP and NKA at pH 2.0. Continuous electric stimulation of the pelvic nerve in cats at 4 Hz during 1 s with 10 s rest produced a marked release of NKA-LI and SP-LI from the colon to blood. Reflex activation of the pelvic nervae by mechanical stimulation of the anus or rectal distension produced a less pronounced release of NKA-LI and SP-LI from the colon to blood. There was a simultaneous colonic contraction and vasodilation during each nerve stimulation. Close intraarterial infusions of NKA, neurokinin B, SP, neuropeptide K (NPK), eledoisin and physalemin at doses of 0.1-100 pmol/min induced dose-dependent proximal and distal colonic contractions and vasodilation, NKA being the most potent. The effects of the tachykinins were reduced after tetrodotoxin and atropine, but unchanged after treatment with hexamethonium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Intraepithelial bodies in colorectal adenomas: Leuchtenberger bodies revisited.

The presence of intraepithelial inclusion bodies (Leuchtenberger bodies) was recorded in rectal or colonic specimens from 130 patients. Large to moderate number of intraepithelial bodies were recorded in 81.8 percent of 55 colorectal adenomas from patients with familial adenomatous polyposis (FAP). Conversely, none of the 55 non-FAP adenomas or of the 20 specimens with ulcerative colitis (10 with dysplasia) had similar amounts of intraepithelial granules. Feulgen studies demonstrated that the granules contain DNA and are probably nuclear fragments of destroyed lymphocytes. Although the pathogenesis of this phenomenon remains obscure, it appears that the presence of large to moderate number of intraepithelial bodies in colorectal adenomas should strongly raise the suspicion of FAP.

Adenoma↗
PubMed1991

Electrosurgery-induced endotracheal tube ignition during tracheotomy.

Electrosurgery was the most common source of ignition for operating room fires prior to the advent of lasers. When combined with volatile anesthetic mixtures, electrosurgery has caused ignition of plastic, rubber, paper, enteric gases, and combustible preparation solutions. We report on an intubated patient whose polyvinyl chloride endotracheal tube ignited during a tracheotomy performed with an electrosurgical unit. The oxygen-rich environment, the polyvinyl chloride tube, and the heat generated by the electrosurgical unit combined to produce a fire. Since otolaryngologists are called upon often to perform tracheotomies on intubated patients, it is imperative that they understand the factors involved in the development of such a fire. This case is presented with an explanation of why this type of fire occurs. A brief review of the literature is included. Different kinds of electrosurgical units, precautions as to their use, and the management of electrosurgery-induced endotracheal tube fires are also discussed.

Child, Preschool↗
PubMed1991

Occurrence of autoantibodies against intrinsic factor, H,K-ATPase, and pepsinogen in atrophic gastritis and rheumatoid arthritis.

The occurrence of autoantibodies against intrinsic factor, H,K-ATPase, and pepsinogen was analysed by means of enzyme-linked immunosorbent assay in three groups of sera. Group 1 comprised sera from 14 rheumatoid arthritis patients with normal acid secretion; group 2, sera from 18 rheumatoid arthritis patients with reduced acid secretion; and group 3, sera from 11 patients with pernicious anaemia or achylia. Groups 1 and 2 were rheumatoid factor-positive, and group 3 was negative. Intrinsic factor autoantibodies were low in groups 1 and 2. In group 3, 9 of the 11 sera (82%) scored positive. The highest titres of H,K-ATPase and pepsinogen autoantibodies were found in groups 2 and 3. Only one serum in group 1 scored positive against H,K-ATPase, and two against pepsinogen, whereas corresponding values were 11 (61%) and 7 (39%) in group 2, and 10 (91%) and 6 (55%) in group 3. Autoantibodies against H,K-ATPase from a pool of patient sera recognized both the alpha- and beta-subunits of the enzyme. The present results support the hypothesis of an autoimmune disease overlap between non-organ-specific rheumatoid arthritis and organ-specific pernicious anaemia.

Adenosine Triphosphatases↗
PubMed1990

Role of VIP in local control of secretion.

Vasoactive intestinal peptide (VIP) is a potent stimulant of duodenal HCO3- secretion and may, like prostaglandins, have a stimulatory role in the local duodenal HCO3- response to luminal HCl. Using a proximal duodenal loop in conscious rats, we examined the local luminal release of HCO3-, VIP and prostaglandin (PG) E2 in response to increasing concentrations of HCl (0.01-150 mmol l-1), perfused for 5 min at 60-min intervals. HCO3- and PGE2 were detected in all basal saline perfusate effluents, and were increased in a concentration-dependent manner by all acid concentrations tested. VIP was increased in a concentration dependent manner from pH 3. Exogenous VIP did not affect the basal luminal output of PGE2, or vice versa. Inhibition of prostaglandin synthesis by indomethacin augmented the HCl-stimulated luminal release of VIP, as well as the HCO3- response to exogenous VIP. The results are in agreement with previous studies, demonstrating that PGE2 is an important regulator of the duodenal HCO3- response to HCl in the rat. In addition, prostaglandins may negatively modulate the release of VIP from local VIPergic neurones, as well as the HCO3- secretagogue effect of VIP. Released VIP may contribute to the HCO3- response at pH less than or equal to 3.

Acid-Base Equilibrium↗
PubMed1990

Cholinergic mechanisms involved in release and effect of prostaglandin E2 in HCl-stimulated duodenal HCO-3 secretion in the conscious rat.

Using a proximal duodenal loop in conscious rats, we investigated interactions between prostaglandin E2 and nicotinic and muscarinic receptor mechanisms previously found to be involved in the duodenal HCO3- response to HCl. In previous studies using the same model, a 5-min perfusion of the duodenal loop with 150 mmol l-1 HCl produced a marked and sustained HCO3- response. In the present study, the identical challenge produced a rapid 20-fold increase in the luminal output of prostaglandin E2 during acid exposure, followed by a sustained more than twofold elevation above the basal level during the 45 min monitored. The prostaglandin synthesis inhibitor indomethacin (4 mg kg-1 i.p.) suppressed the output of prostaglandin E2 during the HCl challenge from 131 +/- 84 to 15.4 +/- 10.0 pmol cm-1 h-1, and in the post-stimulatory period from 17.3 +/- 9.1 to 4.4 +/- 2.2 pmol cm-1 h-1. The nicotinic receptor antagonist hexamethonium (20 mg kg-1 i.v.) had no effect on the output of prostaglandin E2. The muscarinic receptor antagonist atropine (0.5 mg kg-1 s.c.) had no effect on the output of prostaglandin E2 during HCl challenge, but reduced the post-stimulatory output to 7.7 +/- 4.1 pmol cm-1 h-1. Perfusion of the duodenal loop with 0.1 mmol l-1 prostaglandin E2 produced a HCO3- response that was abolished by hexamethonium (20 mg kg-1 i.v.), but not affected by atropine (0.5 mg kg-1 s.c.).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Common skin lesions of the elderly.

The elderly patient can present with a variety of skin lesions of the head and neck. This article is designed to acquaint the otolaryngologist-head and neck surgeon with normal skin morphology and with the changes that occur with aging and sun exposure. Common benign and malignant skin lesions of the aging patient are discussed.

Head and Neck Neoplasms↗
PubMed1990

Evaluation and treatment of complications of thyroid and parathyroid surgery.

The major complications of thyroid and parathyroid surgery include hemorrhage, respiratory obstruction, hyperthyroid storm, hypoparathyroidism, and laryngeal nerve injury. In this article, the incidence, diagnosis, and treatment of various complications are reviewed, with emphasis on hypoparathyroidism and vocal cord paralysis, either bilateral or unilateral. Thyroplastic phonosurgery and carbon dioxide laser arytenoidectomy, two recent surgical additions to the rehabilitation of vocal cord paralysis, are described in depth.

Aluminum Hydroxide↗
PubMed1989

The effect of arachidonic acid and its metabolites on acid production in isolated human parietal cells.

The effect of arachidonic acid and its metabolites on the histamine-stimulated acid production in human isolated parietal cells provenient from endoscopic biopsies was examined. 14C-aminopyrine (14C-AP) accumulation in the parietal cells was used for evaluation of acid production. Histamine dose-dependently increased AP uptake. Histamine stimulation (taken as 100% at 10(-5) M) was significantly inhibited by prostaglandin (PG) E2 to 66 +/- 7% at 10(-8) M, 42 +/- 8% at 10(-6) M, and 13 +/- 10% at 10(-4) M (mean +/- SEM, n = 10). PGF2 alpha, PGD2, and PGI2 showed significant inhibitory effects only at very high concentrations (10(-5)-10(-4) M). Leukotriene (LT) B4 and LTC4 were without effect. The basal acid production (taken as 0%) was lowered significantly by 10(-6) M arachidonic acid to -20 +/- 7.4% (p less than 0.02, n = 10), and the histamine-stimulated (10(-6) M) acid production from 100% to 64 +/- 7.2% (p less than 0.001, n = 10). Aspirin (10(-3) M) increased basal (45 +/- 9.6%, p less than 0.001, n = 10) and histamine-stimulated (10(-6) M) acid production (164 +/- 16.3%, p less than 0.001). It is concluded that PGE2, the major product from arachidonic acid metabolism in the human gastric mucosa, is a significant inhibitor of the histamine-stimulated human parietal cell and may, in humans, play a role as a local physiologic inhibitor of acid secretion.

Adult↗
PubMed1989

Concentrations of cholestenoic acids in plasma from patients with liver disease.

The concentrations of 3 beta-hydroxy-5-cholestenoic acid, 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acid were determined in plasma from patients with different liver diseases and compared with those of unconjugated and conjugated C24 bile acids. The levels of the cholestenoic acids were similar in patients with extrahepatic cholestasis and in controls (median concentration 153 and 162 ng/ml, respectively), whereas significantly elevated levels were found in plasma from patients with primary biliary cirrhosis (median concentration 298 ng/ml) and alcoholic liver cirrhosis (median concentration 262 ng/ml). As expected, conjugated C24 bile acids were elevated in most patients whereas the corresponding unconjugated compounds were low in cholestasis and elevated in alcoholic liver cirrhosis. The levels of the individual C27 acids were usually positively correlated to each other and also to the levels of conjugated C24 bile acids in plasma from patients with liver cirrhosis. In contrast, there was no correlation between the levels of C27 acids and conjugated bile acids in patients with extrahepatic cholestasis. The levels of unconjugated C24 bile acids were not correlated to C27 acids or conjugated bile acids in any of the groups. The results indicate that there is a close metabolic relationship between the individual C27 acids, that they do not participate in an enterohepatic circulation, and that the liver is important for their elimination/metabolism.

Aged↗
PubMed1989

Concentrations of cholestenoic acids in plasma from patients with reduced intestinal reabsorption of bile acids.

The concentrations of 3 beta-hydroxy-5-cholestenoic acid, 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acid were determined in plasma from patients treated with cholestyramine or subjected to resection of the ileum or colon. The values were compared with those for conjugated and unconjugated C24 bile acids. Patients with an intact ileum but without colon had normal levels of cholestenoic acids. Patients treated with cholestyramine or with ileal resection had elevated levels of 7 alpha-hydroxy-3-oxo-4-cholestenoic acid (median values 189 and 233 ng/ml, respectively, compared to 85 ng/ml in controls). The levels of the other two C27 acids were normal in cholestyramine-treated and low in ileoresected patients and were positively correlated to each other but not to the 3-oxo-delta 4 acid. There were no consistent correlations between the levels of C27 acids and those of conjugated or unconjugated C24 bile acids. The results indicate an increased formation of 7 alpha-hydroxy-3-oxo-4-cholestenoic acid in subjects having a stimulated activity of cholesterol 7 alpha-hydroxylase.

Adult↗
PubMed1988

Levels of 7 alpha-hydroxy-4-cholesten-3-one in plasma reflect rates of bile acid synthesis in man.

A method for analysis of 7 alpha-hydroxy-4-cholesten-3-one in plasma is described. Following solid-phase extraction/purification the compound is determined by high-performance liquid chromatography using a UV detector. The median concentration in healthy subjects was 12 ng/ml (range 3-40). The levels were lower in diseases associated with a low bile acid production: extrahepatic cholestasis, less than 1.5 ng/ml (range less than 0.9-3); liver cirrhosis less than 1.5 ng/ml (range less than 0.9-38), and higher in diseases associated with a high bile acid production: cholestyramine treatment, 188 ng/ml (range 54-477); ileal resection 397 ng/ml (range 128-750). The levels were essentially normal in patients with colon resection. The results are consistent with a strong positive correlation between the levels of 7 alpha-hydroxy-4-cholesten-3-one in plasma and the rate of bile acid synthesis.

Adult↗
PubMed1988

Topical prostaglandin E2 in the treatment of chronic leg ulcers--a pilot study.

The results of treatment with topical PGE2 dispersed in hydrocolloid granules, in nine patients with chronic leg ulcers is reported. The healing process was evaluated by stereophotogrammetry, which enables objective measurements of ulcer area and volume. Ulcers in eight patients healed completely and that in the ninth, almost completely. These results suggest that topical PGE2 has a beneficial effect in the treatment of leg ulcers.

Administration, Topical↗
PubMed1988

Construction of ileal reservoir with longitudinal ileal myotomy.

An attempt was made to construct an ileal reservoir in 15 colectomized dogs by making a longitudinal myotomy of 15 cm length. The volume of the myotomized ileal segment did not increase, even when accompanied by more than 50 per cent obstruction of the distal sigmoid colon for periods of follow-up to 4 months. Peristalsis was not altered by the longitudinal muscular incision on the antimesenteric side of the ileum. Although the operative technique for longitudinal ileal myotomy has the benefit of simplicity compared with construction of an ileal reservoir, the latter techniques, which have been used clinically on an extensive basis, are more likely to produce a consistent distension that is suitable for fecal storage. Although there were no leaks from the mucosa and no complications occurred in the 15 dogs evaluated, the dilatation of an isolated ileal segment was so minor that this technique appears to have little application in the treatment of patients undergoing the endorectal ileal pullthrough procedure.

Animals↗
PubMed1987

Comparison of transit times in the J-shaped and the isoperistaltic lateral ileal reservoir--using isotope technique in rabbits.

An ileal reservoir appears to reduce stool frequency and urgency in conjunction with endorectal ileal pull-through operations. The optimal type of reservoir construction has not been determined. In a rabbit model, the isotope transit time, measured as a percentage of isotope remaining in a segment of intestine one hour after injection, was 79% for the J-shaped reservoir (JR) and 57% for the lateral isoperistaltic reservoir (LR). Transit times in ileal segments longitudinally incised and closed and control segments were 49% and 63%, respectively. The mean reservoir volume three months after operation was 53 mL for LR, 101 mL for JR, 20 mL for longitudinally incised and closed ileal segments, and 25 mL for control segments. Although reservoir function between the LR and JR may be similar at six to nine months postoperatively, it appears that the JR empties more slowly and becomes more distended during the first three months after construction in the rabbit model studied.

Animals↗
PubMed1987

Prostaglandins in clinical treatment of gastroduodenal mucosal lesions: a review.

E-type prostaglandins inhibit gastric acid secretion and stimulate gastroduodenal bicarbonate and mucus secretion as well as the formation of hydrophobic surfactant-like phospholipids in the gastric epithelial cells. Furthermore, E-type prostaglandins have trophic effects on the gastro-duodenal mucosa. These effects may partly explain the unique protective effects of E-type prostaglandins against experimental damage of gastroduodenal mucosal lesions in animals and humans. E-type prostaglandins have been used in clinical trials on peptic ulcers, on upper gastrointestinal bleeding, and on mucosal lesions induced by non-steroid anti-inflammatory drugs. In nearly all trials natural prostaglandin E2 as well as the synthetic prostaglandin analogues arbaprostil, misoprostol, enprostil, rioprostil, trimoprostil, and rosaprostol accelerated the healing of peptic ulcers compared with placebo. The PGE analogues must be given in gastric acid antisecretory dosage to reach healing rates similar to those of cimetidine. The drugs seem to be safe, and diarrhoea--the main adverse effect--occurs rarely. Future studies are necessary to identify the place of prostaglandins among other drugs used in peptic ulcer treatment. In the treatment of acute upper gastrointestinal bleeding, arbaprostil was not more effective than placebo in spite of several case reports suggesting that prostaglandin E analogues would be helpful in these situations. E-type prostaglandins were effective in preventing gastroduodenal mucosal lesions caused by non-steroid anti-inflammatory drugs, but the long-term efficacy of prostaglandins has to be established in studies on patients under continuous anti-inflammatory treatment.

Anti-Inflammatory Agents, Non-Steroidal↗