The vasorelaxant effects of amrinone on neonatal rabbit thoracic aortic strips

The present study was designed to compare the in vitro vasorelaxant responses to the bipyridine compound amrinone of prostaglandin F2 alpha (PGF2 alpha) precontracted aortic strips isolated from newborn (2 to 3 days old) and nonpregnant adult rabbits. Changes in forces were recorded isometrically. The effects of isoproterenol (beta-adrenergic receptor stimulator), forskolin (direct activator of adenylate cyclase) and theophylline (non-specific phosphodiesterase inhibitor) were also studied simultaneously. The vasodilator responses to amrinone, forskolin and theophylline in aortic strips from neonates were comparable to those of strips from adults. In contrast, the maximum relaxations to isoproterenol were significantly reduced in those from neonates as compared with those from adults, suggesting that beta-adrenergic receptor mediated responses are not fully developed in the neonate. The mean value for the ED50 concentration (half the maximum response) for amrinone, isoproterenol and theophylline was 1.10 +/- 0.10 x 10(-4) M, 3.47 +/- 1.31 x 10(-8) M and 1.53 +/- 0.10 x 10(-4) M, respectively, in the neonatal group and 1.17 +/- 0.19 x 10(-4) M, 3.75 +/- 1.11 x 10(-8) M and 1.75 +/- 0.06 x 10(-4) M, respectively, in the adult group; there were no significant differences between the neonatal and adult preparations. We concluded that the vasorelaxation produced by phosphodiesterase inhibitors demonstrated no maturation-related changes probably due to a stable cyclic AMP turnover through an unaltered phosphodiesterase activity in newborn and adult arteries.

Presence of prostaglandin EP4 receptor gene expression in a rat gastric mucosal cell line

RGM-1 is an epithelial cell line established from gastric mucosa of adult Wistar rats. In this study, we characterized this newly established cell line by Northern blot analysis. We also investigated deoxyribonucleic acid (DNA) synthesis and hexosamine production in RGM-1 by PGE2. Northern blot analysis did not detect any transcript of proton pump, gastrin receptor, histidine decarboxylase, somatostatin and pepsinogen 1, indicating the absence of characteristics of parietal, ECL, D and chief cells in RGM-1 cells. However, this periodic acid-Schiff (PAS)-positive cell line expressed prostaglandin EP4 receptor mRNA but not EP1 and EP3 receptor mRNAs. [3H]-thymidine incorporation into DNA of the cells was not increased by PGE2. In contrast, PGE2 increased hexosamine content in RGM-1 cells. These results suggest that RGM-1 may be a useful model of gastric mucosal cells and that PGE2 plays a role on mucin synthesis in RGM-1 cells possibly via EP4 receptors.

Effect of adamantylamide dipeptide on reinfection resistance after primary infection eradication in experimental Schistosomiasis mansoni

The immunomodulatory effect of adamantylamide dipeptide (AdDP) was tested in Schistosoma mansoni-infected challenged mice and infected praziquantel-treated (2 x 500 mg/kg) challenged animals. In AdDP-treated mice, the drug was given 58 days post infection of mice with 120 S. mansoni cercariae, challenged with 240 cercariae one day after treatment, while in praziquantel-treated mice, the drug was given 44 days post infection, two weeks post treatment (58 days post infection) they were given AdDP in the same dose and one day later challenged with the same cercarial load. AdDP increased the resistance against reinfection (90.3% vs. 83.5% in infected challenged control). The significant increase in resistance against reinfection was accompanied by significant increase in the percentage of lymphocytes forming EAC rosettes. Mice cured of their primary infection by praziquantel showed a significant reduction in percent resistance, hepatic granuloma size and intragranulomal Thy+ 1,2 and Lyt+ 1 T cells. In mice treated with both praziquantel and AdDP, resistance to reinfection was significantly higher than in mice treated with praziquantel only (89.29% vs. 62.13%) reaching a level comparable to that recorded in infected-challenged controls. Meanwhile granuloma size was not significantly different from that in the infected-challenged controls with a significant rise in Lyt+ 1 T cells. Data may suggest a role for granuloma as a mechanical obstacle and/or as a T cell-mediated reaction in maintenance of resistance to reinfection. A role for B lymphocytes should be considered as the rise of percent resistance to reinfection in mice treated with AdDP alone was accompanied by a significant increase in the percentage of B lymphocytes forming EAC rosettes. Moreover, findings may suggest the use of AdDP together with specific chemotherapy in endemic areas where reinfection and repeated treatment with its consequences are of common occurrence.

Gene expression of keratinocyte and hepatocyte growth factors during the healing of rat gastric mucosal lesions

BACKGROUND & AIMS

The factors that stimulate the growth of gastric mucosal cells during gastric mucosal healing are not completely understood. This study was designed to investigate the gene expression of keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) in the healing of gastric mucosal lesions.

METHODS

Northern blot analysis and reverse-transcription polymerase chain reaction were used to show HGF and KGF messenger RNA.

RESULTS

Transcripts of HGF and KGF were not shown in rat gastric mucosal epithelium but were found in submucosal and muscular layers under normal conditions. When acute gastric mucosal lesions were induced by indomethacin treatment, expression of HGF messenger RNA was augmented in submucosal, muscular, or serosal layers, whereas the transcript of KGF was not influenced. When rat gastric mucosal epithelial cell line RGM1 and rat gastric mucosal primary culture cells were incubated with HGF or KGF, their proliferation was enhanced.

CONCLUSIONS

The results showed increased gene expression of HGF together with constant production of KGF during gastric mucosal healing.

Paradoxical clinical deterioration despite near-complete pathological response to neoadjuvant chemotherapy for locally advanced gastro-oesophageal adenocarcinoma

Neoadjuvant chemotherapy for proximal gastric cancer has shown promise in early clinical trials. We report on a clinical deterioration, yet near-complete pathological and radiological response to a combination of cisplatin and fluorouracil in a patient with locally-advanced gastric adenocarcinoma.

Case of pelvic relapse in a child suffering from acute lymphoblastic leukemia

We describe here a case of an eight years old child suffering from acute lymphoblastic leukemia. She developed pelvic infiltration of leukemic cells while in bone marrow remission and receiving maintenance chemotherapy. She also developed leukemic infiltration of Central Nervous System and died of complications resulting from massive pelvic relapse. With greater number of children in bone marrow and CNS remission, the issue of possible greater predisposition to extramedullary relapse has been discussed. The need for greater vigilance towards pelvic surveillance has been stressed.

Establishment of primary epithelial cell culture from elutriated rat gastric mucosal cells

Proliferating cells in the gastric mucosal epithelium were successfully enriched by counterflow elutriation in a medium-sized cell fraction. When inoculated on culture plates coated with E-C-L cell attachment matrix, these cells differentiated into mucus-producing cells after reaching confluence. Northern blot analysis did not detect any transcript of the proton pump, histidine decarboxylase, somatostatin, or pepsinogen I, indicating the absence of parietal, ECL, D, and chief cells in the confluent monolayer. These mucus-producing cell monolayers that respond to various growth factors may be a suitable model with which to investigate the function of gastric mucus cells in vitro.

Biopotency of vitamin E in lucerne meal for chickens

In order to estimate the biopotency of vitamin E in lucerne/alfalfa meal in comparison to that of dl-alpha-tocopheryl acetate (dl-alpha-Ta; all-rac-alpha-Ta) a study was conducted with newly hatched White Leghorn male chicks. An increase in the vitamin E level in the liver and plasma, and the prevention of nutritional encephalomalacia (NE) were used as criteria for biopotency. After a vitamin E depletion period of one week posthatching, the chicks continued on a semipurified, vitamin E free basal diet without vitamin E supplementation, or were repleted with graded levels of that vitamin for six weeks, provided as extracted lucerne oil or as dl-alpha-Ta. High performance liquid chromatography (HPLC) with fluorescence detection was used for the analysis of the vitamin E homologues. The diagnosis of NE was based on clinical and histopathological observations. A significant increase (P < 0.05) in vitamin E content in the liver and plasma was observed in response to dietary supplementation with both vitamin E sources. The linear increase both in the liver and plasma storage assays was associated with a reduced incidence of NE. The disease was totally prevented by a dietary supplement of 7.50 and 5.40 mg vitamin E/Kg feed provided as dl-alpha-Ta or lucerne oil, respectively. The natural biopotency of the vitamin E in lucerne meal compared with that of dl-alpha-Ta in the liver and plasma storage assays and in the prevention of NE was 123, 105 and 99%, respectively, as calculated by the slope ratio technique.

A prevalence survey of mental disorders among children in a rural Malaysian village

This is the first epidemiological survey of mental disorders among children in a Malaysian village. The WHO Research Questionnaire for Children (RQC) was used for initial screening followed by a semistructured interview, the Follow-up Interview for Children (FIC) at its second stage. Diagnosis was obtained by using Rutter's multi-axial classification. The prevalence rates obtained for the diagnostic categories were described in 3 age groups, in accordance with the age of attending school in Malaysia. Of 507 children screened aged 1-15, 6.1% were classified as having a mental disorder.

Histopathological and biochemical changes associated with selenium and vitamin E deficiency in chicks

One day old unsexed White Leghorn chicks obtained either from commercial hens fed adequate levels of selenium (Se) and vitamin E (VE) (Comm. chicks), or from hens depleted in both nutrients (Depl. chicks), were fed a low Se-VE semi-synthetic basal diet. The dietary Se content was kept constantly low, while graded levels of VE as dl-alpha-tocopheryl acetate (dl-alpha Ta), (0, 5, 10 or 15 mg VE/kg diet) were fed for six weeks. An efficient carry-over of Se and VE from hens to their progeny was observed by a significant increase in their muscle Se, liver Se-glutathione peroxidase (Se-GSH-Px), and VE content at hatching. In the Depl. chicks, signs of Se-VE deficiency, i.e. exudative diathesis (ED) were observed at hatching, indicating that the deficiency lesions had developed during the embryonic period, whereas these signs were not observed in Comm. chicks on the depletion diets until they were 2 weeks old. The VE supplemental level of 15 mg/kg was not adequate to provide a complete protection against ED. Exudative diathesis was associated with low levels of muscle Se, liver Se-GSH-Px and VE and was also accompanied by a simultaneous increase in the liver non-Se-GSH-Px. Autopsy findings and histopathological lesions were observed only in subcutaneous tissue and skeletal muscle. The subcutaneous tissue was edematous with hyaline vascular lesions and hemorrhages. The thigh muscles were more susceptible to deficiency lesions than were the breast muscles, and showed in acute stages degenerative processes of the muscle fibers including calcium deposits, vascular lesions and hemorrhages. In subacute and chronic cases, reparative changes and muscle damage may develop independently of the hyaline vasculosis. To prevent ED, adequate Se and VE in chick diet is essential after hatching, irrespective of their tissue reserves of both nutrients at 1 day of age.

Utilization of dietary sodium selenite, barley, oats and meat meal selenium by the chick

The biological availability of selenium (Se) in barley, oats and meat meal as compared to that in sodium selenite was determined by whole blood glutathione peroxidase (GSH-Px) activity and Se concentration depletion-repletion bioassays. One day old White Leghorn chicks, initially of low-Se status, were further depleted for Se by feeding a low-Se casein basal diet (0.03 mg Se/kg diet) adequate in vitamin E for the first two weeks of life. Repletion treatments of Se at graded levels supplemented by the natural sources or sodium selenite were then provided for 4 weeks. A multiple regression equation was calculated to relate the final whole blood GSH-Px activity and Se concentration to the dietary intake of Se. The percent biological availability of Se present in the natural sources was evaluated by slope ratio analyses in comparison to the standard, sodium selenite (100%). The activity of whole blood GSH-Px established a relative bioavailability for barley, oats and meat meal Se of 85, 41 and 25%, respectively (as mu kat/l), and 81, 51 and 17%, respectively (as mu kat/g Hb). The estimated bioavailability of Se in the different natural sources, as measured by blood Se concentration was: barley, 104%; oats, 99% and meat meal, 69% in comparison to that of sodium selenite. Thus, selenite Se was superior to the natural Se sources for the induction of GSH-Px activity. Barley Se appeared to be of higher biological value to chicks than did oats and meat meal Se. Even though meal Se was retained in appreciable amounts in chick blood, it showed the poorest utilization for the synthesis of blood GSH-Px.

Response of whole blood, erythrocyte and plasma vitamin E content to dietary vitamin E intake in the chick

Whole blood, red blood cells (RBC), and plasma vitamin E (VE) levels in chicks fed dietary VE (dl-alpha-tocopheryl acetate, dl-alpha Ta) supplementation in steps of 0.0, 5.0, 10.0, 15.0, 20.0 and 30.0 mg/Kg were determined to examine their usefulness as an index of VE status. The increase in VE level was significant and linear in whole blood (r = 0.90), RBC (r = 0.89) and plasma (r = 0.93) in response to dietary VE intake. There was a close correlation between VE in plasma vs whole blood (r = 0.90), plasma vs RBC (r = 0.91) and whole blood vs RBC (r = 0.95). The plasma VE content was 1.2-1.8 times greater than that of whole blood, and 6.6-12.5 times greater than that of RBC. The plasma total lipids content was not affected by the dietary VE intake, whereas the level of VE in the plasma total lipids was significantly increased with increasing supplementation. Alpha tocopherol was the major isomer (ca 92%) of VE in whole blood, RBC and plasma at hatching. The small proportions of beta-tocopherol (ca 2%), gamma-tocopherol (ca 5%) and alpha-tocotrienol (ca 1%) observed at 1 day of age had decreased or totally disappeared by 7 days of age after feeding the VE-free basal diet. The data showed that in the chick, the whole blood and RBC levels of VE were as sensitive and reliable indexes of dietary VE status as was that of the plasma.

Evidence that glutamate mediates axon-to-Schwann cell signaling in the squid

High-frequency stimulation (100 Hz) of isolated giant axons of the small squid Alloteuthis subulata and the large squid Loligo forbesi caused the periaxonal Schwann cell resting potential (Em = -40 mV) to hyperpolarize up to 11 mV in direct proportion to train duration and action potential amplitude. In both species, the Schwann cell also hyperpolarized up to 17 mV with the application of L-glutamate (10(-9) to 10(-6) M), in a dose-dependent manner. By contrast, in the presence of 10(-8) M d-tubocurarine (d-TC) to block the cholinergic component of the Schwann cell response, Schwann cells depolarized 8-9 mV during electrical stimulation of the axon or application of L-glutamate. In the presence of 10(-5) M 2-amino-4-phosphonobutyrate (2-APB), the hyperpolarization to glutamate and to axon stimulation was blocked, whereas the cholinergic (carbachol-induced) hyperpolarization was unaffected. In experiments with Alloteuthis, L-aspartate (10(-7) M) also caused a Schwann cell hyperpolarization, but this was not blocked by 2-APB. In tests with glutamate receptor agonists and antagonists, quisqualate (10(-5) M) produced a hyperpolarization blocked by 10(-4) M L-glutamic acid diethylester (GDEE), which also blocked the response to axonal stimulation. Kainic acid (10(-4) M) also caused a hyperpolarization, but n-methyl-D-aspartate (NMDA; 10(-4) M), ibotenate (10(-5) M), alpha-amino-3-hydroxy-5-methyl-isoxazole proprionate (AMPA; (10(-4) M), and isethionate (10(-5) M) had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies of axon-glial cell interactions and periaxonal K+ homeostasis--III. The effect of anisosmotic media and potassium on the relationship between the resistance in series with the axon membrane and glial cell volume

The effect of anisosmotic physiological solutions and [K+]o on the resistance in series with the axon membrane were studied in medial giant axons of the crayfish, Procambarus clarkii, to determine if changes in series resistance are correlated with changes in glial cell volume and volume regulatory responses. Series resistance was estimated from computer analysed voltage waveforms generated by constant current and space clamp techniques using piggy-back axial wire current passing and glass pipette recording electrodes. Axons subjected to anisosmotic physiological solution in the range of 23 to 175% of isosmolar solution demonstrated that the series resistance of axons changes in a manner similar to that expected for a volume change in isolated cells. In hyperosmotic solution the series resistance changes biphasically, initially decreasing followed by a recovery of the series resistance, similar to the regulatory volume increase described for glial cells in culture. The increase in series resistance following the initial decrease is inhibited by bumetanide (0.1 mM). Ouabain (1 mM), an inhibitor of the volume decreasing Na-K pump, causes the series resistance to increase significantly above that seen for the no-drug control. Bumetanide, an inhibitor of the volume increasing Na-K-Cl cotransporter, inhibits the volume regulatory response to anisosmotic media. Treating the axon with three times normal external [K+] causes the series resistance to decrease approximately 15% while five times normal [K+] leads to a 15% increase in series resistance. Both ouabain and d-tubocurare (10(-p8) M) prevent the three-fold [K+]-induced decrease in series resistance while carbachol (10(-7) M) and bumetanide have little effect. On the other hand, ouabain enhances the five-fold [K+]-induced increase in series resistance while carbachol and bumetanide cause the five-fold [K+] response to be in a decreasing direction. d-Tubocurare has little effect on the five-fold [K+]-induced increase in series resistance. The study demonstrates that under the conditions of these experiments changes in series resistance are a reflection of changes in cell volume modulated by ouabain- and bumetanide-sensitive K+ uptake mechanisms. The effects of carbachol and d-tubocurare on the series resistance suggest that their effects are modulated through their actions on the glial cell membrane potential and the electrochemical gradient for K+, which in turn controls the amount of K+ that appears in the periaxonal space.(ABSTRACT TRUNCATED AT 400 WORDS)

Studies of axon-glial cell interactions and periaxonal K+ homeostasis--II. The effect of axonal stimulation, cholinergic agents and transport inhibitors on the resistance in series with the axon membrane

The small electrical resistance in series with the axon membrane is generally modeled as the intercellular pathway for current flow through the periaxonal glial (Schwann cell) sheath. The series resistance of the medial giant axon of the crayfish, Procambarus clarkii, was found to vary with conditions known to affect the electrical properties of the periaxonal glia. Series resistance was estimated from computer analysed voltage waveforms generated by axial wire-constant current and space clamp techniques. The average series resistance for all axons was 6.2 +/- 0.5 omega cm2 (n = 128). Values ranged between 1 and 30 omega cm2. The series resistance of axons with low resting membrane resistance (less than 1500 omega cm2) increased an average of 30% when stimulated for 45 s to 7 min (50 Hz) whereas the series resistance of high membrane resistance (greater than 1500 omega cm2) axons decreased an average of 10%. Carbachol (10(-7) M) caused the series resistance of low membrane resistance axons to decrease during stimulation but had no effect on high membrane resistance axons. d-Tubocurare (10(-8) M) caused the series resistance of high membrane resistance axons to increase during stimulation but had no effect on low membrane resistance axons. Bumetanide, a Na-K-Cl cotransport inhibitor and low [K+]o, prevented the stimulation-induced increase in series resistance of low membrane resistance axons but had no effect on the high membrane resistance axons. The results suggest that the series resistance of axons varies in response to the activity of the glial K+ uptake mechanisms stimulated by the appearance of K+ in the periaxonal space during action potential generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary C-peptide in the neonate correlates both to maternal glucose tolerance and to fetal size at birth

In 18 women with gestational diabetes the variables of an oral glucose tolerance test (fasting and 2-hour blood glucose values and area under the blood glucose curve) performed in the last trimester of pregnancy correlated significantly with the urinary C-peptide excretion during the first 12 hours of the life (r = 0.47, 0.71, and 0.60, respectively). In a combined group with 28 type II pregnant diabetic women there was also a significant correlation between the urinary C-peptide excretion of the infants and their skinfold. Assay of the urinary C-peptide excretion of the neonate, reflecting its insulin production, seems to be a sensitive parameter to study the influence of the maternal carbohydrate metabolism in the offspring.