Indomethacin inhibits cell proliferation in the oxyntic epithelium of the rat

The aim of this investigation was to examine the action of parenteral indomethacin and oral prostaglandin E2 on cell proliferation in the rat oxyntic mucosa. Groups of Sprague Dawley rats were treated with either 1.5 mg/kg indomethacin subcutaneously, 5 mg/kg oral prostaglandin E2 or placebo, twice daily during 5 days. All rats were killed exactly 4 hours after mitotic arrest with vincristine, and a biopsy specimen from the oxyntic mucosa was processed for routine microscopic evaluation. Mitotic figures were distributed cluster-like along the oxyntic mucosa alternating with mitosis-free areas. The total number of mitotic figures in 8 mm of mucosa was significantly reduced by administration of indomethacin (p < 0.05). In rats given indomethacin, 32.5% of the examined mucosa did not have mitotic figures, which is significantly higher than 14.3% as observed in placebo-treated rats (p < 0.05). Both rats treated with indomethacin and with prostaglandin E2 had fewer microscopic fields containing 5-6 mitotic figures than placebo-treated animals (p < 0.05). The maximal length of mitosis-free areas was 0.6 (0.6-0.9) mm in rats given indomethacin which is significantly larger than 0.4 (0.2-0.4) mm observed in controls (p < 0.05). Indomethacin produced epithelial atrophy as shown by a significant reduction of the epithelial height observed in those rats compared to controls (p < 0.05). The inhibition of cell proliferation observed in the oxyntic mucosa of rats treated with the cyclooxygenase blocker indicates that an important physiological role of endogenous prostaglandin is to maintain the proliferative activity of the epithelium at a high level.

The characteristics of mitotic figures in jejunal mucosa of patients with celiac disease

The morphologic characteristics of the mitotic figures present in the jejunal mucosa of 23 pediatric patients having gluten enteropathy were recorded. Of the 851 mitoses found, 4.9% were in prophase, 39.9% in prometaphase, 29.5% in metaphase, 22.3% in anaphase, and 3.3% in telophase. Of the 851 mitoses found, 98.8% were considered to be morphologically normal and the remaining 1.2% were considered atypical. The occurrence of atypical mitoses in the jejunal mucosa of pediatric patients was unexpected. However, because jejunal adenocarcinomas in celiac patients are known to be rare, the plausible explanation for the present findings is that the occurrence of atypical mitoses may mirror morphologic variations from the normal mitotic pattern occurring in a rapidly proliferating mucosa, such as that of patients with gluten enteropathy.

Fluorescamine-induced membrane permeability in mitochondria

1. Addition of fluorescamine (75 microM) to mitochondria induced an increase in membrane permeability. 2. The leakiness of the inner mitochondrial membrane is characterized by extensive release of accumulated Ca2+, collapse of the transmembrane potential, mitochondrial swelling and efflux of matrix proteins, among them, malate dehydrogenase. 3. These effects were diminished by supplementing the media with 1 mM phosphate, and partially prevented by Mg2+. 4. These results indicate that the primary amino groups of membrane components contribute, partially, to the maintenance of the permeability barrier in mitochondria.

Somatostatin cells in the oxyntic mucosa of hypo- or hypergastrinemic rats

The present report describes the long-term effects of antrectomy, antrum exclusion, portacaval shunt, omeprazole treatment, or the combination of omeprazole treatment and portacaval shunt on the number and density of somatostatin cells in the oxyntic mucosa of the rat. Antrectomy, which is associated with hypogastrinemia, raised the number and density of the somatostatin cells, whereas antrum exclusion and omeprazole treatment, which are associated with hypergastrinemia, reduced the number and density of the somatostatin cells. Portacaval shunt, which is associated with hypogastrinemia, increased both the number and the density. Omeprazole treatment of portacaval--shunted rats suppressed or even reversed the somatostatin cell hyperplasia after portacaval shunt alone. From these findings it is unlikely that gastrin stimulates the proliferation of somatostatin cells in the oxyntic mucosa. In fact, there seems to be an inverse relationship between the serum gastrin concentration and the somatostatin cell number.

Oral prostaglandin E2 influences the enterochromaffin-like and somatostatin cell populations in the oxyntic mucosa of the rat

Our aim was to study the effects of long-term oral administration of different doses of prostaglandin E2 (PGE2) and of a synthetic analogue on the endocrine cells and on selected epithelial cells of the rat oxyntic mucosa. The endocrine cells were visualized by immunohistochemical staining and by the Sevier-Munger method. Quantification of the mucosal cells was performed at a light-microscopic level using stereological methods. The highest dose of 15-R-15-methylprostaglandin E2 (MePGE2) increased the total volume of enterochromaffin-like (ECL) cell profiles whereas no changes were observed after treatment with PGE2. On the other hand, the total mucosal volume of chromogranin A-immunoreactive cells was significantly reduced by both doses of natural PGE2. The highest dose of PGE2 increased the total volume of somatostatin-immunoreactive cells. The serotonin-immunoreactive cells were very few and unaffected by treatments. E2 prostaglandins induced hyperplasia and hypertrophy of epithelial cells. A selective trophic action on the mucous but not on the parietal cells was observed. The area of the parietal cells was increased in rats treated with the analogue. The gastric acid content was increased in rats treated with the highest doses of E2 prostaglandins. The plasma level of somatostatin was significantly increased in rats given MePGE2 and the highest dose of PGE2. The cell population of chromogranin A-immunoreactive cells did not reach the levels of the NECL cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Indomethacin accelerates clearance of labeled cells and increases DNA synthesis in gastrointestinal mucosa of the rat

Sprague-Dawley rats treated with placebo, parenteral indomethacin, or oral prostaglandin E2 for six days were given an intraperitoneal injection of [3H] methyl-thymidine and killed at 45 min and 96 hr after labeling. Treatments were continued until death. The dpm/DNA index was determined in mucosal scrapings of the stomach, duodenum, and jejunum and used to estimate DNA synthesis (45 min) and the clearance of labeled cells (96 hr). Indomethacin increased the DNA synthesis in both the duodenal and jejunal mucosa (P less than 0.05). In comparison to the controls, the clearance of labeled cells from the antral, duodenal, and jejunal mucosa was accelerated by indomethacin treatment, whereas the elimination of labeled cells from the antral and jejunal mucosa was slowed by PGE2 treatment (P less than 0.05). DNA synthesis of the antral mucosa was significantly reduced by PGE2 (P less than 0.05). The cyclooxygenase blocker did not affect the cell kinetic parameters of the oxyntic mucosa. The plasma levels of somatostatin were significantly higher both in PGE2- and indomethacin-treated rats than in controls (P less than 0.05). It is concluded that indomethacin treatment increases the cell losses from the epithelial surface, which in turn trigger a compensatory trophic reaction. It is suggested that an important physiological action of endogenous prostaglandins is to regulate the outflow of cells from the superficial zones of the epithelium. Finally, this study disclosed the presence of hitherto unknown regulatory mechanisms that promote cell proliferation in the gastrointestinal mucosa despite inhibition of the synthesis of endogenous prostaglandins.

E2 prostaglandins modulate cell proliferation in the small intestinal epithelium of the rat

Groups of Sprague-Dawley rats were administered 1 mg/kg indomethacin subcutaneously, indomethacin subcutaneously plus 200 micrograms/kg oral 15-R-15 methyl-prostaglandin E2 (MePGE2) or oral MePGE2 twice daily for 10 days. The animals were treated with antibiotics to prevent mortality. Two control groups were used: control 1 was given placebo and control 2 was treated with antibiotics. All rats were killed 4 h after injection of a metaphase blocker, and the proliferative activity of the distal small intestine was examined in histological sections by means of the cumulative mitotic index (MI). A reduction in the number of villous cells was observed in the rats given antibiotics (p < 0.05 vs. control 1). The small intestinal villi of the rats treated with indomethacin had fewer cells than those of both control groups (p < 0.05) whereas the crypts contained more cells (p < 0.05) and had a higher MI than those of the controls (p < 0.05 vs. controls 1 and 2). These changes were reverted by the prostaglandin analogue. The number of cells of the small intestinal crypts and the cumulative MI in the rats who received indomethacin and the prostaglandin analogue were similar to controls, and they were significantly lower than the values observed in the animals treated with indomethacin (p < 0.05). The animals treated with the prostaglandin analogue and placebo developed a marked hyperplasia of the small intestinal villi (p < 0.05 vs. both control groups), but the atrophy of the villi induced by indomethacin was not prevented by simultaneous administration of the analogue.(ABSTRACT TRUNCATED AT 250 WORDS)

Trophic doses of E2 prostaglandins do not influence the exocrine and endocrine pancreas in the presence of high levels of plasma somatostatin

The aim of the present investigation was to study the effect of a long-term and a short-term treatment regimen with 15-R-15-methyl prostaglandin E2 and natural prostaglandin E2 (PGE2) on the endocrine cell populations of the rat pancreas. Graded oral doses of the analogue (5 and 50 micrograms/kg) and PGE2 (5000 micrograms/kg) were given twice daily for 4 weeks. The pancreas was carefully excised and weighed. Sections from randomly taken pancreatic biopsy specimens were processed for immunohistochemistry or hematoxylin and eosin staining before quantitative estimations were made, using stereologic methods. The total pancreatic volumes of insulin-, glucagon-, polypeptide P-, somatostatin-, and chromogranin A-immunoreactive cells were not affected by E2 prostaglandins. Neither the total volume of the islets of Langerhans nor that of the pancreatic cell nuclei was affected. The size of pancreatic cell nuclei was the same in the groups. The plasma levels of the antitrophic peptide somatostatin were significantly increased in rats treated with doses of both the analogue and PGE2 (p less than 0.05). In an additional short-term study rats were given oral placebo or 5000 micrograms/kg PGE2 twice daily for 5 days. The total endocrine pancreatic volume was not affected by PGE2. As in the long-term study, natural PGE2 did not affect the total pancreas volume or the total volume of pancreatic cell nuclei. These findings indicate that E2 prostaglandins produce no changes in the exocrine or endocrine pancreas in a dose range known to induce hyperplasia in the gastrointestinal epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic laparoscopy

Laparoscopy is a unique procedure which can be used in diagnostic or therapeutic situations involving intra-abdominal pathology. Until recently, open laparotomy has been the preferred method for such evaluations. The following cases indicate the increased sensitivity, specificity, safety, and cost effectiveness of laparoscopy in diagnostic situations.

Distribution of control of oxidative phosphorylation in mitochondria oxidizing NAD-linked substrates

The flux control distribution of the net rate of state 3 respiration was determined in heart and kidney mitochondria incubated with low concentrations of pyruvate (0.5 mM) or 2-oxoglutarate (1 mM), and in conditions that led to activation of NAD-linked dehydrogenases, i.e., high substrate or Ca2+ concentrations. Control of flux was exerted by the ATP/ADP carrier (flux control coefficient, ci = 0.37) and Site 1 of the respiratory chain (ci = 0.28) when dehydrogenase activity was low. Control of the process shifted to the ATP synthase (ci = 0.32) and the Pi carrier (Ci = 0.27) when dehydrogenases were activated by high pyruvate and high Ca2+. The changes in the control exerted by the ATP/ADP carrier and the ATP synthase were not due to changes in the transmembrane potential, nor to a modification of intramitochondrial ATP/ADP ratios. Applying the summation theorem of the control analysis, it was found that at low Ca2+ and pyruvate concentrations the dehydrogenases shared the control of state 3 respiration with other steps. The NAD-linked dehydrogenases did not exert any significant control at high Ca2+ or high pyruvate concentrations.

Prostaglandin E2-induced hyperplasia of the rat antral epithelium is followed by a secondary inhibition of the mitotic activity

The aim of the study was to examine the mitotic activity in the antral and duodenal epithelium of Sprague-Dawley rats given trophic doses of E2 prostaglandins during a prolonged period of time. Natural prostaglandin E2 (dose range: 0.2-5.0 mg.k-1) and 15 (R) 15 methyl prostaglandin E2 (dose range: 0.03-2.0 mg.kg-1) were administered for 11 days, and mitoses were arrested with vincristine for 4 h before estimation of the cumulative mitotic index. A dose-related hyperplasia of the antral glands was observed after treatment with prostaglandin E2 and the synthetic analogue (p less than 0.05). The proliferative zone was enlarged in rats treated with high doses of the analogue but natural prostaglandin E2 did not affect the limits of the proliferative zone. A dose-related reduction of the mitotic index was observed in animals treated with prostaglandin E2 despite the presence of hyperplastic changes. All doses of the analogue induced antral hyperplasia without affecting the mitotic index except in rats given the highest dose who had a significantly lower mitotic index than controls (p less than 0.05). Hyperplasia of both crypts and villi was observed in the duodenum of rats given high doses of E2 prostaglandins (p less than 0.05) whereas the mitotic index and the growth fraction were not affected by treatments. It is concluded that hyperplasia by prostaglandins is developed in absence of changes of the mitotic activity. The observed reduction of the mitotic index is interpreted as a secondary phenomenon, possibly mediated by a regulatory mechanism of cell proliferation which is triggered to reduce further epithelial growth. It is suggested that prostaglandin E2 might influence such regulatory mechanisms.

[Coronary angioplasty in the treatment of symptomatic myocardial ischemia with one vessel disease]

Our group initiated a program of coronary angioplasty (CA) in patients with symptomatic one vessel disease, or multivascular lesions with a critical "culprit" stenosis. In a 16 month period we have performed CA of 28 lesions in 25 patients (20 men) with a mean age of 54 +/- 10 years. Stable angina was diagnosed in 14 patients, unstable angina in 7, and post-myocardial infarction residual angina or stenosis in 4 patients treated with streptokinase. Successful dilatation was obtained in 23 (82.1%) of 28 stenotic segments, reducing the stenosis from 90 +/- 8% (range 70-100) to 9 +/- 12% (range 0-30; p less than 0.00001). In 4 cases with total occlusion, dilatation was not obtained, and in one case the procedure was complicated by fatal brain embolism. There were 4 complications due to coronary occlusion or spasm, all of them resolved during CA without sequelae. The 20 cases with primary success have been followed during an average of 8.6 months. In three cases (15%) restenosis was detected; two of them underwent surgery, and CA was repeated successfully in the other. Disappearance of myocardial ischemia was confirmed in 14 patients, and functional improvement in the other three. In conclusion, CA is an effective and relatively safe therapeutic alternative in different clinical forms of coronary heart disease with a single vessel stenosis, or in selected cases of multivascular lesions with a critical stenosis.

Oral E2 prostaglandins affect endocrine cell populations in the gastric antrum of the rat

The aim of the present study was to investigate antral endocrine cell populations and tissue and circulating hormone levels following a 4-week oral regimen with prostaglandin E2 (25, 250 and 5000 micrograms/kg-1 b.i.d.) or a stable methyl analogue (5 and 50 micrograms kg-1 b.i.d.). Epithelial hyperplasia of the gastric antrum was observed with the highest dose of prostaglandin E2 and both doses of the analogue, as evaluated by stereological methods and conventional cell count. The treatments significantly affected the endocrine cell population. Somatostatin-immunoreactive cells were increased in proportion to the increased epithelial cellularity and plasma levels of somatostatin were increased in parallel. The tissue content of somatostatin-like immunoreactivity differed according to the extraction procedure used, and was significantly higher than controls in specimens extracted in neutral water. In the neutral extracts an immunoreactive somatostatin of unidentified molecular structure dominated quantitatively over somatostatin 14 and 28, which were the major components in acetic acid extracts. The serotonin-immunoreactive cell population was also significantly increased by natural prostaglandin E2 and the analogue but the gastrin cell population was not significantly affected by treatments. Accordingly, no significant changes were observed in tissue or plasma gastrin levels. It is concluded that the epithelial hyperplasia of the antral epithelia produced by E2 prostaglandins is associated with selective changes of endocrine cell populations. The changes were proportional to the increases of epithelial cellularity and required quantitative determination of the total antral volume to be detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prostaglandin E2 on disease activity, gastric secretion and intestinal permeability, and morphology in patients with rheumatoid arthritis

The effects of oral natural prostaglandin E2 (PGE2) on symptoms, disease activity, and gastrointestinal functions in rheumatoid arthritis (RA) were studied in an open pilot trial. Twelve patients, six taking and six not taking non-steroidal anti-inflammatory drugs (NSAIDs), received 1 mg natural PGE2 three times a day for six weeks. The treatment was tolerated well and the only side effect noted was slightly looser stools in three patients. Half of the patients reported subjective improvement and none had aggravation of symptoms. The Ritchie articular index and several biochemical inflammation markers decreased and were significantly reduced at the end of the treatment period. The thickness of the small intestinal mucosa increased during the PGE2 treatment. The intestinal permeability pattern, measured by urinary excretion of polyethylene glycols (PEG 400), differed between the patients taking and not taking NSAIDs. The initially high urinary PEG 400 excretion values in the patients taking NSAIDs decreased and the initially low excretion values in patients not taking NSAIDs increased during the PGE2 treatment. The jejunal contents became sterile in 5/6 patients not taking NSAIDs and remained sterile in 1/6 patients taking NSAIDs at the end of the treatment. The treatment period was associated with a reduction of lactobacilli in patients not treated with NSAIDs. Thus the treatment appeared to decrease disease activity and to improve small intestinal functions in patients with RA, findings that need confirmation in a controlled trial.

Initial kinetic changes of prostaglandin E2-induced hyperplasia of the rat small intestinal epithelium occur in the villous compartments

This study was performed to further identify the sequence of cell kinetics that occurs in the development of gastric and intestinal epithelial hyperplasia after orally administered prostaglandins of the E series. A high-dose, short-treatment schedule was used to examine the initial effects on kinetic parameters in the rat small intestinal epithelium. Groups of rats were killed after a single dose of oral prostaglandin E2 at 1 h after in vivo labeling with [methyl-3H]thymidine and during continued treatment at 6, 12, 24, 48, 72, and 96 h. As evidenced by autoradiography, the earliest change produced by prostaglandin E2 was an increased cellularity of the villous compartment (p less than 0.05 after 24 h). There was no change of labeling index of the villous compartment or of the leading edge of labeled cells within 24 h. At 48 h, the increased cellularity was accompanied by a significantly elevated labeling index of the villi. Throughout the study period no significant differences were observed between groups in the number of cells or labeling indices in the jejunal crypts, or in cellular input from the crypts to the villi. Epithelial turnover time in the placebo and treatment groups was 69 and 71 h, respectively. To exclude the possibility that prostaglandin E2 initially affects cell birth rate and mean cell cycle time, a metaphase blocker was given after 4 days of treatment in a second study. Animals were killed after 0, 0.5, 1.0, 1.5, and 2.5 h. The rate of entry into mitoses was 8.1% cells/h in controls compared with 8.2% cells/h in treated rats. The distribution of mitoses within crypts was identical in the two groups and the mean cell cycle time was 13.6 and 13.2 h, respectively. Also in this study there were trophic changes of the villi. It is concluded that the hyperplasia produced by oral prostaglandin E2 starts in the villi of the small intestine and is initiated by reduced cell exfoliation from the villous tips. Previously recorded retention of cellular elements in villi and crypts, increased cellularity of the proliferative compartments, and reduced mitotic index are secondary events.

A method for the quantitation of intestinal metaplasia of the stomach by morphometry

A novel method to quantitate the extent of intestinal metaplasia in gastrectomy specimens is presented. Morphometric measurements of histochemically labeled mucin-producing goblet cells were done in three selected gastrectomies (one having a peptic ulcer, one with adenocarcinoma of the intestinal type, and one with adenocarcinoma of the diffuse type). The sectioning of the gastrectomy specimens was standardized. The results indicated that the intestinal metaplasia was significantly higher in the specimen with adenocarcinoma of the intestinal type (as compared to the other two specimens), both along the lesser and greater curvatures as well as in the fundic area. These quantitative results confirm nonquantitative reports based on subjective visual impressions. This quantitative histochemical method for measuring the actual length as well as the topographical distribution of intestinal metaplasia in resected stomachs will be used in future studies of intestinal metaplasia with the aim of disclosing possible differences among populations with disparate incidences of gastric carcinoma.

Alternating proliferative capacity in the rat gastrointestinal mucosa. Effects of E2 prostaglandins and indomethacin

Having previously observed an apparent uneven distribution of proliferating cells in the gastric corporic mucosa of the rat, we examined the mitotic distribution along 8-mm sections of gastric and jejunal epithelia. Metaphases were arrested with vincristine to facilitate mitotic count, and the effects of treatment with a prostaglandin E2 analogue and a cyclooxygenase blocker were examined. Clusters of mitotic figures alternating with non-proliferating areas were observed in the gastric corporic epithelium of control rats. During 4 h mitotic activity was absent over 21% of the corporic mucosa. Extending the examined area to about 240 glands reduced substantially the error of mitotic counts. An uneven distribution of mitoses was found in the antral and jejunal epithelium, but areas without proliferating cells were uncommon. Treatment with the prostaglandin E2 analogue reduced the number of mitosis-free areas in the gastric corpus to 13%, and clusters were less easily identified. The total mitotic count was unaffected by treatment. In the jejunum prostaglandin increased the absolute number of mitoses. The mitotic span was also increased, reflecting the uneven distribution. Indomethacin produced the opposite effects to the prostaglandin analogue, including reduction of epithelial height. Of the gastric corporic mucosa 35% was non-proliferating during the observation period, but the clustering phenomenon was still apparent. Absence of dose relationship was attributed to ulcerogenic actions of high doses of indomethacin. It is concluded that mitoses are unevenly distributed in the upper gastrointestinal epithelium of the rat and that safe estimates of mitotic count require examination of large corporic areas.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA synthesis in the gastroduodenal mucosa during acute and chronic stress in the rat

We investigated the effects of acute and chronic stress on the DNA synthesis of the gastroduodenal mucosa of the rat using two different methods of physical stress at various time intervals. Acute stress was produced in the rats being briefly plunged or swimming for two hours (water temperature 37 degrees C). "Sham - transported" rats were used as controls. The results indicate that in the stomach the DNA synthesis was substantially reduced during acute stress in both groups tested (when compared to controls). The DNA synthesis was also reduced in experimental rats after one and two weeks of stress (as compared to day one). By four and eight weeks, the rate of DNA synthesis in the gastric mucosa had significantly increased in the stressed animals. Controls demonstrated significantly lower DNA values following two to eight weeks of stress (as compared to day one). From the outset, the DNA replication values were 2.5 to 3 times higher in the duodenal mucosa than in the gastric mucosa. Following two weeks of stress, the duodenal mucosa of both test groups showed significantly lower DNA values than controls, but significantly higher values after four weeks of stress. By eight weeks, the duodenal mucosa in all rats had reached the same values as that of day one. This was considered a sign of "adaptation to stress" in the duodenal mucosa. The above results suggest that the fluctuations of DNA replication may be connected to compensatory mechanisms aimed at adjusting the gastroduodenal mucosa to protracted stress situations.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction, the trace formula, and semiclassical asymptotics

We state a theorem that relates the theory of dimensional reduction in Hamiltonian mechanics to the spectral properties of elliptic operators with symmetries on compact manifolds. As an application, we show that the spectrum of the Schrödinger operator, -[unk]hDelta + V, as [unk]h --> 0, contains geometric information about the closed trajectories of a classical particle with Hamiltonian p(2) + V(q). More generally, we show that this is true for particles with internal degrees of freedom and subject to an external Yang-Mills field, the classical limit being the Wong-Sternberg-Weinstein system for such particles.

Cell cycle distribution of proliferative and functional cells of the rat jejunum after treatment with oral E2 prostaglandins

Proliferative and functional epithelial cells were isolated from jejunal specimens of the rat by means of vibrational treatment combined with differential air insufflation. This method gave a good separation between superficial cells of the villi and the crypt cells, as evaluated by flow cytometry, morphology, cytology, and incorporation of radioactive thymidine into DNA. Groups of Sprague-Dawley rats (260 g) were treated twice daily for 11 days with oral placebo, 15(R)15-methyl-prostaglandin E2 in the range of 0.125-2 mg X kg-1, or 5 mg X kg-1 natural PGE2. Isolated crypt cells and superficial cells of the jejunal villi were then analysed by flow cytometry. Morphometric measurements were performed on sections of some jejunal specimens not submitted to vibrational treatment. The cell cycle distribution of crypt cells was unaffected by treatment with the prostaglandin analogue despite the presence of trophic changes. The proportion of crypt cells in G2/M phase was slightly but significantly reduced in rats given natural PGE2 compared with controls. The cell cycle distribution of villus cells was not affected by prostaglandin treatment. Trophic changes in the absence of increased DNA synthesis (S phase) or increased mitotic activity suggests that the hyperplasia observed after prostaglandin treatment is due to a reduced cell loss and/or slower migration time of epithelial cells.

Cell proliferation of the rat gastrointestinal mucosa after treatment with E2 prostaglandins and indomethacin

The frequency of arrested mitoses after vincristine injection was studied in the gastrointestinal mucosa of rats treated with either natural prostaglandin E2 (0.2-5.0 mg X kg-1, b.d.), 15-R-15 methyl prostaglandin E2 (2 mg X kg-1, b.d.) or indomethacin (1.0-3.0 mg X kg-1, b.d.). In addition to the mitotic index, morphometric measurements including the mucosal thickness and the thickness of the proliferative and functional zones of the gastric corpus, antrum and jejunum were performed. Natural prostaglandin E2, at the highest dose range, reduced significantly the mitotic index in the gastric antrum. Normal values were found in the gastric corpus and jejunum and in the antrum with the lower doses. The mitotic index was unaffected by treatment with 15-R-15 methyl prostaglandin E2. Natural prostaglandin E2 produced trophic changes (i.e. increased thickness and/or hyperplasia) in the antrum, functional epithelial zone of the gastric corpus and in the jejunum. More pronounced trophic changes were observed in the mucosa of rats treated with the analogue. Indomethacin reduced the mucosal thickness in all examined epithelia and lowered the mitotic index in the jejunum. It is concluded that the trophic effects of E2 prostaglandins on gastrointestinal epithelia are not caused by increased production of new cells. The reduced mitotic index observed in the antral mucosa of prostaglandin-treated rats could be secondary to a negative feedback from the hyperplastic epithelium. The antitrophic effects of the prostaglandin-synthesis blocker (indomethacin) indicates that endogenous prostaglandins may participate in the epithelial cell regulation of the gastrointestinal tract.

Effect of oral prostaglandin E2 on DNA turnover in gastric and intestinal epithelia of the rat

The mucosal incorporation and clearance of a DNA precursor was examined in the rat stomach and intestine following oral treatment with natural prostaglandin E2 (PGE2) or 15(R) 15 methyl prostaglandin E2 (Me PGE2). Control groups received vehicle or pentagastrin. After five days of treatment animals were labelled with methyl-3H-thymidine. Groups of rats were killed at 0.75, 24, 72, 96 and 120 h after labelling. Treatments continued until killed. Mucosal scrapings were analysed for radioactivity and DNA. Morphometric measurements were performed and plasma levels of gastrin and somatostatin determined. PGE2 and its stable analogue produced hyperplasia within one week of treatment, in particular of the gastric antrum and changed the incorporation and clearance of radioactive thymidine from gastric and intestinal epithelia. The most consistent finding was a delayed elimination of thymidine from the mucosa, indicating a slowing of the DNA turnover. The DNA synthesis was differently affected along the gastrointestinal tract, being unchanged or reduced in the stomach and moderately increased in the intestine. Prostaglandin treatment was associated with a three- to ten-fold increase of the gastric acid contents and with elevated plasma levels of gastrin and somatostatin. It is concluded that E2 prostaglandins produce hyperplasia of gastric and intestinal epithelia in the rat by prolonging the cell survival time rather than by increasing new cell production. Hypergastrinemia is not a likely mediator of trophic actions of E2 prostaglandins, which develop despite elevated plasma levels of somatostatin.

Cell kinetics of rat gastrointestinal mucosa. Autoradiographic study after treatment with 15(R)15-methyl-prostaglandin E2

Forty Sprague Dawley rats (120 g) were divided in groups of five rats each, and 2 mg , kg-1 15(R)15-methyl-prostaglandin E2 or vehicle was administered orally, twice daily for 5 days. On the 6th day, 1 mCi . kg-1 methyl-3H-thymidine was given intraperitoneally to all rats. Groups of rats were killed at 45 min and 24 h, 72, and 120 h after the labelling. Treatments were continued until death. Samples were taken from the corpus, antrum, and jejunum and processed for autoradiography. Microscopic evaluation of the proliferative and functional compartments included cell counts and determination of the labelling index (LI) and mitotic index (MI). Prostaglandin treatment increased the number of cells in the jejunal and gastric epithelia. The DNA synthesis, evaluated from the LI and 45 min after thymidine injection, was unaffected by treatment. The clearance of label from jejunal crypts and villi was significantly slower in the prostaglandin groups. Similar observations were made in the proliferative zone of the corporal and antral epithelia. The MI was unchanged or reduced by prostaglandin treatment, the reduction being significant after 8 to 10 days' treatment. It is suggested that the trophic action of prostaglandin E2 is produced by reduction of epithelial cell losses, thereby prolonging the cell survival time. The reduced MI may be secondary to negative feedback from the hyperplastic epithelium. Trophic actions are produced by short-term treatments.

Trophic actions of E2 prostaglandins in the rat gastrointestinal mucosa. A quantitative morphologic study

Adult, male Sprague-Dawley rats in groups of 10 received one of the following treatments orally twice daily for 3 wk: prostaglandin E2 (PGE2) 7.5 mg X kg-1, 15(R)-15-methyl prostaglandin E2 (MePGE2) at 0.2 or 2.0 mg X kg-1, or vehicle. After 18 h of fasting and 10-12 h after the last dose, the rats were anesthetized, and the gastrointestinal tract was fixed and processed for macroscopic and microscopic investigations. Trophic changes were more pronounced in the gastric antrum than in the gastric corpus or small intestine. The thickness of the antral mucosa was significantly increased by PGE2 and in a dose-related way by MePGE2. The mucosa of the gastric corpus became significantly thicker only with the higher dose of MePGE2. In all the prostaglandin-treated groups, the proportion of endocrine cells was reduced. Small--but sometimes significant--changes were registered in the proportions of the various exocrine cells. The parietal cells became significantly larger (+88%) in the rats treated with high doses of MePGE2. The secretory surface of the parietal cells was markedly increased by PGE2 and MePGE2. The enlargement of the secretory surface in animals treated with prostaglandins corresponded to a marked elevation of the basal gastric acid secretion and an increase in plasma gastrin levels. Hypergastrinemia can explain some, but not all, of the trophic changes observed in this study. Light microscopic examination of the duodenal and jejunal mucosa showed dose-related increases in villus heights and crypt lengths after treatment with MePGE2. Only the duodenal villus heights were increased by PGE2.

Protection of the gastroduodenal mucosa by prostaglandins

Like other nucleated cell populations in the body, the cells of the gastroduodenal mucosa are capable to metabolise arachidonic acid into prostaglandins, with prostaglandin E2 as the probable major metabolite. The production increases on demand and can be followed in the gastric lumen, where the output of prostaglandin E2 increases two to fourfold after exposure of the mucosa to hydrochloric acid. Exogenous prostaglandins, in particular of the E series, stimulate several identified mucosal defense factors in the upper gastrointestinal tract. Prostaglandins of the E series stimulate the transport of bicarbonate and the production and release of mucus glycoproteins from the gastroduodenal mucosa. They have trophic effects on gastrointestinal epithelia by increasing the survival time of mucosal cells and have cytoprotective properties. In addition, E2 prostaglandins suppress the gastric acid secretion and accelerate peptic ulcer healing. Non steroidal antiinflammatory drugs, which block the biosynthesis of prostaglandins, suppress the bicarbonate secretion, the production of mucus glycoproteins and cytoprotective properties. They interfere with the inhibitory feedback regulation of the gastric acid secretion and are ulcerogenic in experimental and clinical situations. These actions of PG biosynthesis blockers provide indirect information on the importance of local prostaglandin formation for maintenance of gastrointestinal mucosal integrity. It is hypothesised that biosynthesis of prostaglandins in the gastroduodenal mucosa is of importance and may be a key event in triggering the different components of the mucosal defense.

A quantitative method of estimating inflammation in the rectal mucosa. IV. Ulcerative colitis in remission

Histological preparations of the rectal mucosa were analyzed quantitatively in 61 patients with ulcerative colitis in remission (UCR). Four histological variables were recorded: the diameter (minor axis) of the lumen of 10 consecutive (transversally cut) glands, the interglandular linear distance between 10 consecutive glands, the number of glands at high-power field examination, and the number of nuclei in 10 consecutive areas of lamina propria. The most important feature to differentiate UCR patients from non-colitic patients was the distance between glands and the number of glands per area. The sum of the values of the four variables demonstrated that 84% of the patients with UCR had scores of 22 or more, whereas only 1 of 124 non-colitic patients (that is, 0.8%) had similar scores.

Effects of 16,16 dimethyl prostaglandin E2 on irradiation damage of the small intestine

The effects of oral 16,16 dimethyl prostaglandin E2 on irradiation induced damage of the small intestine was examined in the rat. Groups of Sprague-Dawley rats received graded doses of the analogue or placebo at 24, 8 and 0.5 hours before and at 16 and 24 hours following whole abdominal exposure to 10 Gy. Rats were killed 72 hours after irradiation. Pretreatment within the lower dose range had a moderate protective effect with better preserved crypts and crypts to villus ratio. Larger doses seemed to increase the intestinal damage. The prostaglandin treated sham irradiated rats had higher villous height and larger epithelial surface compared with controls.

Amikacin concentration in the cerebrospinal fluid of children with acute bacterial meningitis

Penetration of the aminoglycoside, amikacin, into the cerebrospinal fluid (CSF) of twenty children with acute bacterial meningitis was studied at various times after intramuscular administration and at various stages of therapy. Six of the patients were evaluated during therapy with amikacin at 7.5 mg/kg (intramuscularly) every 12 hours plus ampicillin every 6 hours at 300 mg/kg/day (intravenously); thirteen of the remaining fourteen patients were treated with ampicillin alone, but were given a single intramuscular dose of 7.5 mg/kg of amikacin for evaluation of CSF concentration. Amikacin concentration in CSF with respect to time after administration followed essentially the same pattern as in serum. A minimum concentration of 2 microgram/ml was found in 76% of the CSF samples obtained between 0.5 and 7 hours after administration. A mean amikacin serum/CSF ratio of 3:1 was demonstrated up to 7 hours after dose in all patients who underwent clinical improvement. Patient response was predictable by a correlation of in vitro MIC values with in vivo CSF concentration in three of the six patients who received amikacin therapy.

Amikacin in gram-negative paediatric infections

Amikacin was used in the treatment of various Gram-negative infections in sixty-six children ranging in age from two days to thirteen years. Over 72% of the infections treated were classified as severe and the remainder were moderate. Among infections in which the site of origin was the urinary or gastro-intestinal tract, amikacin achieved thirty-eight (95%) complete or partial cures in forty patients. In respiratory tract infections, amikacin completely or partially cured six (75%) out of eight patients. The remaining eighteen infections involved skin, soft tissue and other miscellaneous categories in which amikacin therapy resulted in seventeen (94%) complete or partial cures. Overall, amikacin achieved fifty-four complete cures and seven clinical or bacteriological cures in sixty-six patients, which represents an 82% complete cure rate and 10% partial cure rate for all the patients in the study.

Clinical and laboratory studies with amikacin in newborns, infants, and children

Thirty (86%) of 35 infants and older children with proven gram-negative sepsis had a complete clinical remission after treatment with amikacin. In 27 (82%) of 33 infectious episodes for which bacteriologic results were available before and after treatment, the organism was eradicated. The dosage of amikacin was either 7.5 mg/kg or 15 mg/kg given intramuscularly at 12-hr intervals. No adverse clinical effects or laboratory abnormalities were observed during treatment, which lasted from five to 14 days. All bacteria were sensitive to amikacin when tested by the disk diffusion method, and all but a single strain of Pseudomonas were sensitive when tested by the agar dilution method. Assays of serum and urine demonstrated adequate levels of amikacin after single intramuscular injections of 3.75 or 7.5 mg/kg; simultaneous assays of serum and cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid during infection. Serial measurements of amikacin in serum from 0.5 to 12 hr after administration of single doses of 7.5 mg of drug/kg to six newborns revealed no significant differences in the concentrations achieved with intramuscular or intravenous administration of the drug.

Effectiveness of two new cephalosporins, cephazolin and cephapirin, administered intermittently in acute and chronic osteomyelitis in children

Ten patients were treated, most of pre-school age, with acute osteomyelitis, produced by Staphylococcus aureus and Salmonella, having evolved for approximately one week, with sodium cephazolin at doses of 60 mg/kg/day intramuscularly in two daily injections for the first seven days and then in a single dose every twenty-four hours for four to seven weeks. Nine of ten patients were asymptomatic six months after this treatment. The patient who manifested chronic signs at the end of six weeks of therapy continued to be treated with three weekly injections of the same drug at an equal dose until the completion of six months, at the end of which he was asymptomatic. Ten patients with chronic osteomyelitis having evolved for two months to five years, due to penicillin-resistant Staphylococcus aureus, were treated with cephapirin at the dose of 30 mg/kg in one daily injection intramuscularly for three to four weeks and then the same dose on Mondays, Wednesdays and Fridays until the completion of six months. Eight patients who required it were sequestrectomized. Seven of the ten patients improve and remained asymptomatic for the same period of observation. The three patients who did not show marked clinical improvement did exhibit an appreciable radiological recovery. We have presented these regimens of treatment with a view of encouraging research into the intermittent administration of bactericidal antibiotics for pyogenic infections; in spite of the good results, we do not dare to recommend them in daily practice.

Amikacin (BBK8) in infections due to gram-negative organisms in children over the age of one month

Thirty children over the age of one month were treated with amikacin (BBK8), a new aminoglycoside derived from kanamycin A, with three intramuscular dosage schedules. Each group consisted of ten patients. The first received 7-5 mg/kg/12 hours, the second 7-5 mg/kg/24 hours and the third, 3-75 mg/kg/12 hours. The infections and the bacteria were similar in all three groups: pyelonephritis, abscesses of soft tissues, infected wounds, septicaemia, superinfected empyema, gastro-enteritis, chronic otitis media; the bacteria were E. coli, Klebsiella, Pseudomonas and Salmonella. A were sensitive by the Kirby-Bauer method, although two were resistant by dilution in Petri dish. Of the thirty patients, twenty four (80%) were cured. The schedule of 3-75 mg/kg/12 hours was as effective as the schedule of 7-5 mg/kg/12 hours for infections such as pyelonephritis, superficial abscesses, contaminated wounds, gastro-enteritis and sepsis. The cases with infections localized in rather unaccessible sites required double the dose and strict drainage and cleanliness. Plasma levels with the administration of 3-75 mg/kg fluctuated between 8-3 and 12-6 mcg/ml; with 7-5 mg/kg they fluctuated between 8-6 and 13-1. The minimum inhibitory level (MIL) for the majority of the bacteria was 1-25 mcg/ml. No toxic reactions were observed.

Lung puncture-aspiration as a bacteriologic diagnostic procedure in acute pneumonias of infants and children

Lung puncture-aspiration is simple and generally innocuous. For the study of acute pneumonia it is superior to examination of naso pharyngeal, throat or laryngeal cultures and gives more positive re sults than does blood culture. It can be extremely useful in investi gational studies and with selected patients in whom identification of the precise pathogen is necessary for optimal antibiotic therapy.