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Biomedical subjects

T Kiviluoto

Publications and source records attributed to T Kiviluoto.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effect of vagotomy on expression of neuropeptides and histamine in rat oxyntic mucosa.

The effect of vagotomy and pyloroplasty on the density of nerve fibers containing bombesin/gastrin-releasing peptide (GRP), calcitonin gene-related peptide (CGRP), and galanin as well as histamine-, 5-hydroxytryptamine (5-HT)-, and somatostatin-containing cells in the oxyntic mucosa of the rat stomach was studied. Ten days after vagotomy and pyloroplasty the density of histamine-containing cells in the oxyntic mucosa was increased by 70% (P < 0.05), and these cells were larger and showed more extensive cell processes than in control animals. The density of 5-HT-immunoreactive (IR) cells and somatostatin-IR cells were not affected. A marked decrease in the density of CGRP-IR nerve fibers and a slighter decrease in the density of GRP-IR nerve fibers was observed in the mucosal layer, while only a minor reduction of CGRP-IR fibers, and no reduction of GRP-IR fibers was seen in the muscular layer. The density of galanin-IR nerve fibers was not affected. The height of the oxyntic mucosa was reduced by about 25% (P < 0.05). Thus, a striking effect on the histamine-IR cells was seen, supporting the view that these cells are regulated by the vagus nerve. The study also indicates that a major portion of the CGRP-IR nerve fibers, and part of the GRP-IR nerve fibers, in the mucosal layer of the fundic region are of vagal origin or regulated by normal vagus nerve activity.

Animals↗
PubMed1994

Laparoscopic gastro-oesophageal antireflux surgery.

Recent improvement in the understanding of gastro-oesophageal antireflux mechanisms and the pathophysiology of the gastro-oesophageal reflux disease (GERD) has warranted the concept that antireflux surgery provides a valid, and sometimes superior, alternative to medical therapy in selected patients. The main indications for surgical treatment of symptomatic GERD are: failure of medical therapy to heal ulcerative oesophagitis or to prevent recurrence of stricture or other complications, and the development of aspiration pneumonia or other airway complications. The Belsey and Nissen fundoplication and the Hill posterior gastropexy are the three most widely used surgical procedures to control reflux. The success rate of these operations, performed openly, in relieving symptoms and healing the lesions is 80-90%. The laparoscopic approach provides an interesting alternative in antireflux surgery. It affords a potential to reduce some inherent complications of conventional surgery, provided the operator is technically experienced and well aware of the pathophysiological principles of this disease. It is also superbly convenient to the patient. The currently published short-term results of laparoscopic antireflux surgery are comparable to those of open surgery, but the technique is still young, and its final evaluation is not possible until long-term results are available.

Female↗
PubMed1993

Preepithelial mucus-HCO-3 layer protects against intracellular acidosis in acid-exposed gastric mucosa.

The role of the preepithelial mucus-HCO-3 layer in protection against intracellular acidosis was investigated in isolated Necturus gastric antral mucosa exposed to luminal acid by simultaneous measurement of intracellular pH (pH(i)) and extracellular surface pH (pHs) in surface epithelium with microelectrode technique. Acidification of the luminal perfusate to pH 2.5 acidified pH(i) in surface epithelial cells from 7.33 +/- 0.02 to 7.20 +/- 0.04, whereas pHs fell from 6.75 +/- 0.21 to 5.20 +/- 0.25 (P < 0.01; n = 9), followed by a steady state for at least 2 h. Inhibition of epithelial HCO-3 secretion and transport by removal of serosal HCO-3 and CO2 (HEPES and O2 substitution) during acid exposure provoked a progressive acidification of pHs from 5.60 +/- 0.41 to 2.74 +/- 0.14 in 30 min (P < 0.01; n = 9), which was accompanied, after a 5- to 10-min delay, by acidification of pH(i) from 7.21 +/- 0.03 to 5.68 +/- 0.26 (P < 0.01). Digestion of the surface mucus gel by pepsin (5% wt/vol) at pH 2.5 caused a slow acidification of pHs from 5.22 +/- 0.59 to 3.60 +/- 0.46 within 2 h. This was followed by a more rapid acidification to 2.53 +/- 0.38 (P < 0.01; n = 7), with concomitant acidification of pH(i) from 7.19 +/- 0.05 to 6.03 +/- 0.33 (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1993

Thoracoscopic fundoplication.

Thoracoscopic fundoplication and hiatoplasty were performed by a videoassisted technique in a patient with longstanding pathologic gastro-oesophageal reflux, reflux oesophagitis and hiatal hernia. Ten months later the patient was asymptomatic and had normal findings by oesophageal endoscopy and 24-hour pH-monitoring. Thoracoscopic fundoplication may be useful in patients with intra-abdominal adhesions due to previous abdominal surgery. Also obese patients with large hiatal hernias and perioesophageal adhesions may benefit from the thoracoscopic approach.

Adult↗
PubMed1993

Enucleation of an intramural lipoma of the oesophagus by videothoracoscopy.

An intramural oesophageal lipoma was enucleated by a videoassisted thoracoscopic technique in a patient with dysphagia and reflux symptoms. His symptoms and erosive reflux oesophagitis healed after the operation, but impaired oesophageal motility persisted as assessed by postoperative manometry four months later. The benefits of the videoassisted technique include decreased operative trauma, a short hospital stay and a rapid return to normal activities.

Adult↗
PubMed1992

Intracellular pH in isolated Necturus duodenal mucosa exposed to luminal acid.

Regulation of intracellular pH (pHi) and its maintenance within physiological ranges during exposure to luminal acid was studied in isolated Necturus duodenal mucosa using liquid sensor microelectrodes. Exposure of the mucosa to luminal pH 2.7 caused significant intraepithelial acidification. Subsequent removal of HCO3-/CO2 (HEPES/O2 substitution) from the serosal perfusate caused a further decrease of pHi. Blocking of HCO3- transport across the basolateral cell membrane by addition of 4-acetamido-4,isothiosyanostilbene-2,2-disulfonic acid (SITS) to serosal perfusate also caused a slight but significant decrease of pHi. Removal of Na+ (choline substitution) from the serosal perfusate during acid exposure likewise caused a significant decrease in pHi, as did serosal addition of an inhibitor of Na+/H+ antiport, 1 mmol/L amiloride. When Na+ was removed from the serosal perfusate after HCO3- removal, pHi first rapidly acidified; this was followed after an initial 5-minute steady state by an uncontrolled progressive acidification at a rate of 0.33 pH unit/15 min without any further steady state. A similar but weaker effect could also be shown with amiloride addition. The epithelial surface pH was 7.13 +/- 0.08 at the apex of mucosal villus and 7.42 +/- 0.11 (n = 5) in the cryptal area between the villi, i.e., greater than 1 pH unit higher than that of the luminal bulk solution (pH 6), thus suggesting active alkalization of the epithelial surface. Removal of serosal HCO3-/CO2 decreased surface pH significantly both at the villus apex and at the cryptal area, suggesting that the surface alkalization is mediated by transport of serosal HCO3- to the epithelial surface. The data suggest that pHi in acid-exposed duodenal mucosa is primarily maintained within physiological range by an HCO3(-)-dependent mechanism, which, at least in part, exerts its action extracellularly by forming an alkaline buffer layer at the epithelial surface. If adequate serosal (or systemic) HCO3- is not available, a second-line Na(+)-dependent and amiloride-sensitive pHi-regulatory mechanism, presumably an Na+/H+ antiport, becomes the main regulator of pHi.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1992

Effects of interferon alpha on insulin binding and glucose transport in human adipocytes.

We have previously demonstrated that interferon administration impairs glucose tolerance and causes insulin resistance in healthy man. Whether this is a direct effect of interferon is not known. The present study was undertaken to examine directly the effect of interferon alpha on insulin binding and action on glucose transport in isolated human adipocytes. Different concentrations of interferon alpha (range 10(-3)-10(5) IU ml-1) and different incubation times (0-5-24 h) with interferon were employed. Acute and 5-h and 24-h exposure of human adipocytes to 10(-2)-10 IU ml-1 of interferon increased the high affinity binding of 125I-insulin (P less than 0.05). In contrast, human interferon alpha had no effect on insulin binding in rat adipocytes. In short-term studies interferon had no effect on 14C-glucose transport clearance. 24-h preincubation of human adipocytes with 10(-2), 10, 10(4) IU ml-1 interferon increased maximally-insulin stimulated 14C-glucose transport clearance (P less than 0.05) and glucose transport responsiveness to insulin was enhanced by 24% (P less than 0.05) in cells exposed to 10(-2) IU ml-1 interferon. After 5 and 24-h preincubations with interferon we observed modest changes in glucose transport sensitivity to moderate concentrations of insulin (50-100 pM) with upregulation in the presence of 10(-2)-10 IU ml-1 interferon and downregulation in the presence of 10(4)-10(5) IUm ml-1 interferon (P less than 0.05). The insulin sensitivity index (ED50) did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1992

Laparoscopic cholecystectomy for symptomatic gallstone disease. Experience of the first 200 cases.

Laparoscopic cholecystectomy was carried out in 200 patients between January 1991 and September 1992 at the Second Department of Surgery, Helsinki University Central Hospital. Mortality was nil. The overall major complication rate was 4% (n = 8). The incidence of common bile duct lesions was 0.5% (n = 1). In seven (3.5%) patients the procedure had to be converted into open cholecystectomy. Repeat surgery was needed in two patients. The average hospital stay was 3.0 +/- 1.5 days and the average sick leave 14 +/- 4 days. Obese and high-risk patients tolerated the procedure well without significant increase in complication rate or hospital stay. Laparoscopic cholecystectomy may be regarded as the treatment of choice for symptomatic gallstone disease.

Adolescent↗
PubMed1991

Exogenous surface-active phospholipid protects Necturus gastric mucosa against luminal acid and barrier-breaking agents.

The nature of the protective action of exogenous surface-active phospholipid on gastric mucosa was studied in isolated Necturus antral mucosa by measuring intracellular pH and intraepithelial potentials and resistances with a microelectrode technique. Exposure of the antral mucosa to luminal pH 2 acidified intracellular pH in surface epithelial cells by 0.6-0.3 pH units. A 20-minute pretreatment with exogenous (pulmonary) surfactanlike phospholipid completely abolished this effect. Obviously, phospholipid protected the mucosa against intracellular acidosis by decreasing the apical cell membrane conductance to H+ (and other ions), because it increased apical cell membrane resistance by +108% and total transcellular resistance by +86% but had no significant effects on paracellular or total transepithelial resistances. In mucosas exposed to three barrier-breaking agents, 10 mmol/L acetylsalicylic acid, 20% (vol/vol) ethanol, and 10 mmol/L taurocholate, at acid luminal perfusate (pH 2.0-2.5), a profound intracellular acidification of 0.9-1.3 pH units/15 min occurred. Pretreatment of the tissue with phospholipid significantly opposed intracellular acidification, but the modulatory influences on the changes in intraepithelial potentials or resistances were less conspicuous and mostly insignificant.

Animals↗
PubMed1991

Different metabolic regulation by adenosine in omental and subcutaneous adipose tissue.

Adenosine content was higher in omental adipose tissue (0.91 +/- 0.13 nmol g-1 of wet weight; mean +/- S.E.M.) than in abdominal subcutaneous adipose tissue (0.42 +/- 0.08 nmol g-1 of wet weight) in rapidly frozen surgical biopsy samples taken from ten patients undergoing elective abdominal surgery. This difference was statistically significant (P less than 0.002). The sensitivity of isoprenaline-stimulated lipolysis to inhibition by N6-(phenylisopropyl)adenosine was studied in omental and abdominal subcutaneous adipocytes isolated from nine patients. The effect of this adenosine Ri-site agonist was less pronounced in omental than in abdominal subcutaneous adipocytes which could be due to a desensitization phenomenon. This difference was statistically significant (P = 0.012). The ratio of the inhibitory guanine nucleotide binding proteins Gi1 and Gi2 to the corresponding stimulatory protein Gs was the same in plasma membranes prepared from omental and abdominal subcutaneous adipocytes. In conclusion, in omental adipose tissue, adenosine content is higher and the response to this nucleoside is less pronounced than in subcutaneous adipocytes. This difference cannot be explained by a different (Gi1 + Gi2)/Gs ratio.

Abdomen↗
PubMed1990

Tolerance of rat duodenum to luminal acid.

The tolerance of the duodenal mucosa to luminal acid was investigated by measuring with a liquid sensor pH microelectrode technique the epithelial surface pH (pHs) and subepithelial tissue pH (pHt) in rat proximal (duodenal bulb, Brunner gland area) and distal duodenum exposed to luminal acid. Under basal conditions, pHs was roughly equal in both parts of the duodenum; proximal duodenum, 7.40 +/- 0.14 (mean +/- SEM) at the villus tip and 7.54 +/- 0.16 at the depth of crypt; distal duodenum, 7.46 +/- 0.19 and 7.55 +/- 0.09, respectively. Yet, exposure of the mucosa to luminal acid (10 mM HCl) provoked a significantly lesser decrease of pHs (0.25 +/- 0.13 vs 0.42 +/- 0.12 pH units) in the proximal duodenum, suggesting that the response of epithelial HCO3 secretion to luminal acid is stronger in that part of the duodenum. Further, the initial acidification of pHs was followed in the proximal duodenum by a secondary alkalinization of pHs, leading to normalization of pHs, which may suggest activation of compensatory protective mechanisms. pHt at the villus tip was likewise roughly equal in both parts of duodenum (7.29 +/- 0.05 vs 7.17 +/- 0.04), but, again, acidification of the luminal perfusate progressively from 10 to 100 mM HCl induced a much earlier and significantly more profound acidification in the distal than in the proximal duodenum. The possible contribution of Brunner glands to the greater mucosal tolerance to acid in the proximal duodenum was assessed by investigating whether stimulation or inhibition of Brunner gland secretion modulates the response of the duodenal mucosa to acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1990

Intracellular pH in isolated Necturus antral mucosa exposed to luminal acid.

Regulation of intracellular pH in gastric epithelial surface cells exposed to luminal acid was investigated in isolated Necturus antral mucosa using microelectrode technique. Exposure of the mucosa to luminal pH 2 acidified intracellular pH from 7.21 +/- 0.01 to 6.95 +/- 0.04 (N = 50). Removal of Na+ from the perfusates or addition of amiloride (1 mM) to serosal perfusate (containing HCO3-) had no influence on intracellular pH during exposure to pH 2 (N = 6), but removal of HCO3-/CO2 from or addition of 4, acetamido-4-isothiocyanatostilbene-2,2-disulfonic acid (0.5 mM) to the serosal perfusate (containing Na+) acidified intracellular pH from 7.02 +/- 0.03 to 6.45 +/- 0.15 (p less than 0.01, N = 10) and from 6.97 +/- 0.06 to 6.58 +/- 0.26 (p less than 0.01, N = 6), respectively, in 15 min. In tissues exposed to mucosal pH 6, epithelial surface pH was about 1.3 pH units higher than pH of the mucosal bulk solution. Removal of Cl-/HCO3- from the serosal perfusate acidified epithelial surface pH by about 0.5 pH units (p less than 0.01, N = 6), suggesting that serosal HCO3- sustains intracellular pH, at least in part, by generating an alkaline buffer layer at the epithelial surface. In the absence of HCO3-/CO2, a stable intracellular pH was obtained when the tissue was exposed to mucosal pH 2.7, but in this situation intracellular pH was sensitive to Na+ removal or amiloride addition, intracellular pH decreasing from 7.00 +/- 0.07 to 6.48 +/- 0.10 (p less than 0.01, N = 6) and from 6.86 +/- 0.06 to 6.32 +/- 0.01 (p less than 0.01, N = 7), respectively, in 15 min. The data suggest that in gastric epithelium exposed to luminal acid, physiological intracellular pH is primarily maintained by the buffer action of serosal HCO3- transported to the epithelial surface to impede the entry of luminal H+ into mucosal tissue. Removal of the sheltering HCO3- unmasks a second line, Na(+)-dependent and amiloride-sensitive intracellular pH regulatory mechanism, presumably a Na+/H+ antiport.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1990

Gastric mucosal acid-base balance.

Acute gastric ulceration induced by haemorrhagic shock is associated with profound intramucosal acidification due to diffusion of luminal H+ into the mucosa. High-HCO3- metabolic alkalosis protects the mucosa against this ulceration, whereas low-HCO3- respiratory alkalosis does not, suggesting that lack of systemic and intramucosal HCO3-, rather than tissue acidosis per se, renders the mucosa susceptible to ulceration. In normal mucosa, disruption of the mucosal barrier by taurocholate, ethanol or acetylsalicylic acid leads to efflux of alkali (HCO3-) from the mucosa, with generation of an alkaline buffer layer at the epithelial surface to protect the mucosa from further damage. In ischaemic mucosa no such protective alkaline layer is formed, and exposure to luminal acid leads to severe acidification of and damage to the mucosa. The efflux of alkali may be driven by capillary hydrostatic pressure, since no such protective alkaline efflux occurs in vitro, but rather exposure to luminal acid and barrier-breaking agents results in intracellular acidification. The potential pathogenetic role of a disrupted intramucosal acid-base balance, as well as the protective effect of systemic and intramucosal HCO3- in acute gastric stress ulceration is further substantiated by the in vitro findings that perfusion conditions simulating in vivo ulcerogenic conditions provoke intracellular acidosis, and serosal HCO3- significantly contributes to the maintenance of normal intracellular pH in surface epithelial cells exposed to luminal acid.

Acid-Base Imbalance↗
PubMed1989

Pseudocysts in chronic pancreatitis. Surgical results in 102 consecutive patients.

Preoperative symptoms, diagnoses, and postoperative outcomes in 102 consecutive patients with pancreatic pseudocysts were analyzed. Upper epigastric pain, loss of weight, obstructive jaundice, and sudden arterial bleeding from the pseudocyst were the most common preoperative symptoms. Ultrasonography, computed tomography, and endoscopic retrograde cholangiopancreatography were the most useful diagnostic tools in the evaluation of the presence, size, location, and possible pancreatic ductal communications of the pseudocyst. In a single thick-walled pseudocyst, the best long-term results were achieved by internal drainage. Pancreatic resection is justified if the patient already has diabetes or multiple pseudocysts or if the pseudocyst is not amenable to internal drainage. The most fatal preoperative complication was a sudden arterial bleeding from a pseudocyst. In treating this complication, hemostasis with transcystic arterial ligation and external drainage of the pseudocyst gave the best results.

Adult↗
PubMed1989

Prostaglandin protection against hemorrhage-induced gastric stress ulceration in the rat.

The present study investigates whether prostaglandins "cytoprotect" the gastric mucosa against hemorrhage-induced stress ulceration by assessing the influence of 16,16-dimethyl prostaglandin E2 (16,16-dm PGE2) on gross and microscopic lesion formation, intramucosal tissue pH, H+ back-diffusion, and mucosal blood flow in rat gastric mucosa exposed to luminal acid (100 mM HCl) during hemorrhagic shock (13 ml/kg for 20 min). Intramucosal tissue pH was measured using pH-sensitive antimony microelectrodes, and mucosal blood flow was measured by the radiolabeled microsphere technique. 16,16-dm PGE2 (5 micrograms/ml topically) significantly protected the gastric mucosa against gross (lesion index 2.25 +/- 0.34 vs 0.87 +/- 0.21) and microscopic (lesion index 2.12 +/- 0.20 vs 0.87 +/- 0.09) damage during the shock. This protection was associated with a significantly lesser acidification of the mucosa during the shock (intramural tissue pH 6.67 +/- 0.08 vs 6.03 +/- 0.17). In order to elucidate whether the lesser intramucosal acidification was due to diminished entry of H+ (H+ back diffusion) into or better disposal of H+ from the mucosa, the influences of 16,16-dm PGE2 on transmucosal H+ fluxes and mucosal blood flow were determined. It appeared that 16,16-dm PGE2 had no influence on the rate of H+ back-diffusion, but it significantly enhanced mucosal blood flow both in the corpus (0.23 +/- 0.04 vs 0.14 +/- 0.03 ml/min/g) and in the antrum (0.24 +/- 0.03 vs. 0.14 +/- 0.03 ml/min/g) during the shock.(ABSTRACT TRUNCATED AT 250 WORDS)

16,16-Dimethylprostaglandin E2↗
PubMed1989

Effect of barrier-breaking agents on intracellular pH and epithelial membrane resistances: studies in isolated Necturus antral mucosa exposed to luminal acid.

Features of "H+ back-diffusion" after disruption of the gastric mucosal barrier were investigated by assessing, with a microelectrode technique, the influence of three barrier-breaking agents, taurocholate (10 mM), ethanol (20% vol/vol), and acetylsalicylic acid (10 mM) on intracellular pH and epithelial membrane potentials and resistances in isolated Necturus antral mucosa exposed to luminal acid (pH 3). Exposure of the mucosa to each of the three agents induced intracellular acidification of surface epithelial cells, but the pattern of pHi behavior was different for each agent: taurocholate induced immediate acidification of pHi, ethanol acidified pHi after a delay of 4-6 min, whereas acetylsalicylic acid initially alkalinized pHi, whereafter a rapid acidification of pHi occurred. Assessment of intraepithelial membrane resistances indicated that taurocholate primarily increases cellular conductance, decreasing in particular Ra. In contrast, ethanol mainly increased paracellular conductance, but also decreased cellular resistance, in particular Ra. Acetylsalicylic acid initially increased cell membrane resistances and Ra/Rb, whereafter a rapid decrease of Ra/Rb and Rt occurred. In each instance, the decrease of Ra/Rb preceded acidification of pHi. The data suggest that all three agents induce intracellular acidification by increasing the conductance of the apical cell membrane to H+, but in ethanol-treated tissues paracellular conductance primarily contributes to H+ back-diffusion.

Animals↗