Entomogenous fungi as promising biopesticides for tick control

When ticks were sealed in nylon tetrapacks and infected with the entomogenous fungi, Beauveria bassiana and Metarizium anisopliae and maintained in potted grass in the field, the fungal oil formulations (10(9) conidia per ml) induced 100% mortality in larvae of Rhipicephalus appendiculatus and Amblyomma variegatum, whereas mortalities in nymphs varied between 80-100% and in adults 80-90%. The aqueous formulations (10(9) conidia per ml) induced mortalities of 40-50% and reductions in egg hatchability of 68% (B. bassiana) and 48% (M. anisopliae) when sprayed on Boophilus decoloratus engorging on cattle. The strains of B. bassiana and M. anisopliae isolated from naturally infected ticks were also found to induce high mortalities in both R. appendiculatus and A. variegatum in tetrapacks placed in potted grass. Both aqueous and oil-based formulations were found to be effective, although the latter induced higher mortalities. These fungal strains in aqueous formulation (10(8) conidia per ml) suppressed on-host populations of adult R. appendiculatus by 80% (B. bassiana) and 92% (M. anisopliae) when sprayed on tick-infested grass once per month for a period of 6 months. The feasibility of using entomogenous fungi for tick control in the field is discussed.

The effect of magnesium sulfate on fetal heart rate parameters: A randomized, placebo-controlled trial

OBJECTIVE

We sought to determine the effect of magnesium sulfate on fetal heart rate baseline value, variability, and acceleration-deceleration pattern.

STUDY DESIGN

Normal, nonlaboring pregnant patients at >30 weeks' gestation were recruited. Baseline fetal heart rate monitoring for 1 hour was performed. After an 800-kcal meal, patients were randomized to receive either an intravenous loading dose of 6 g of magnesium sulfate in 100 mL of isotonic sodium chloride solution or 100 mL of isotonic sodium chloride solution alone. Subsequently, patients in the magnesium sulfate group received a 2-g/h intravenous infusion for 3 hours at a rate of 125 mL/h. Patients randomized to the sodium chloride solution group received a sodium chloride solution infusion at a similar rate (unlabeled intravenous bags). Maternal blood was drawn at 0, 1, and 3 hours for determination of total and ionized magnesium and calcium, electrolyte, and glucose levels. One hour of fetal heart rate monitoring was repeated at 1 and 3 hours of infusion. Tracings were interpreted without identifiers (of time or group) by using the National Institute of Child Health and Human Development fetal heart rate monitoring guidelines.

RESULTS

Magnesium sulfate administration resulted in decreased fetal heart rate baseline values and variability in the third hour. The fetal heart rate baseline value was 134.4 +/- 6.3 versus 136.6 +/- 6.4 beats/min before infusion (P >.05), 134.4 +/- 7.1 versus 135.1 +/- 6. 6 beats/min in the first hour (P >.05), and 134.6 +/- 7.1 versus 132. 3 +/- 7.6 beats/min in the third hour (P <.05) in the sodium chloride solution group versus the magnesium sulfate group, respectively. Fetal heart rate variability (grades 1-5) was 2.75 +/- 0.33 versus 2.82 +/- 0.29 before infusion (P >.05), 2.81 +/- 0.30 versus 2.84 +/- 0.28 in the first hour (P >.05), and 2.71 +/- 0.52 versus 2.67 +/- 0.36 in the third hour in the sodium chloride solution group versus the magnesium sulfate group, respectively (P <. 05). Magnesium sulfate blocked the positive correlation between gestational age and number of accelerations found in control subjects. No significant decelerations were identified.

CONCLUSIONS

Prolonged administration of magnesium sulfate was associated with decreased fetal heart rate baseline values and variability. Given the small magnitude of these changes, the clinical significance of these findings is questionable. Magnesium sulfate inhibition of the increasing number of accelerations with gestational age needs to be considered when fetal well-being is assessed.

Evaluation of fetal echogenic bowel in the second trimester

Previous studies cite different possible etiologies for fetal echogenic bowel (FEB). The purpose of this study was to evaluate the possible etiologies for second-trimester FEB, and to provide clinical guidelines for evaluation of this finding. The study included 79 patients diagnosed with FEB in the second trimester. Fifteen cases (19%) were associated with maternal vaginal bleeding. Of these, 12 patients underwent amniocentesis, 9 of which had visible blood products in the amniotic fluid. Seven cases (8.9%) had associated severe malformation. Seven other cases (8.9%) were noted in multifetal pregnancies. Five fetuses (6.3%) had evidence of bowel obstruction or perforation not associated with cystic fibrosis (CF). Chromosomal aberrations were found in 5 fetuses (6.3%). Intrauterine infection with cytomegalovirus, herpes simplex virus, varicella-zoster virus, or parvovirus B-19 was documented in 5 patients (6.3%). Three cases (3.8%) were associated with subsequent unexplained stillbirth. Two fetuses (2.5%) were found to be affected by CF. Finally, in 30 cases (38%), no obvious reason for FEB was found. We conclude that the evaluation of second-trimester FEB should include targeted ultrasound for associated malformations, infectious studies, DNA analysis for CF mutations, amniocentesis for chromosomal analysis and evaluation of the amniotic fluid for degraded blood products, and an autopsy in cases of stillbirth. Even when no apparent reason is found, pregnancies should be considered at high risk for poor outcome.

Amnioinfusion in the evaluation of fetal obstructive uropathy: the effect of antibiotic prophylaxis on complication rates

OBJECTIVE

Amnioinfusion plays an important role in the intrauterine evaluation and treatment of fetal obstructive uropathy. However, it may significantly increase the risk for chorioamnionitis, premature rupture of membranes and premature labor. We evaluated the impact of prophylactic antibiotics on postamnioinfusion complications.

METHODS

Thirty pregnancies complicated by fetal obstructive uropathy, treated by amnioinfusion and with documentation of pregnancy outcome were identified from our database. Pregnancy outcomes were compared between patients who were treated with prophylactic antibiotics and those with no prophylaxis.

RESULTS

Chorioamnionitis was diagnosed in 3 out of 15 (20%) patients who did not receive prophylactic antibiotics as compared to 2 (13%) in the treated group. The overall rate of serious obstetrical complication was significantly higher in the untreated group (66 vs. 20%; p = 0. 021). Patients receiving prophylactic antibiotics delivered at a significantly greater gestational age than those who did not receive antibiotics (34.0 +/- 3.7 vs. 31.3 +/- 1.9 weeks, respectively; p = 0.018).

CONCLUSIONS

Our study supports the use of oral prophylactic antibiotics as being effective in reducing the previously observed significant risks associated with amnioinfusion in fetal obstructive uropathy.

Augmentation of water-immersion stress- induced gastric mucosal lesions in BALB/c mice infected with Helicobacter felis

BACKGROUND AND AIMS

Inoculation of Helicobacter felis into the murine stomach has been reported to induce chronic gastric inflammation and may be a model of Helicobacter pylori-induced chronic gastritis. In this study, to characterize H. felis-induced gastritis, the gastric production of interleukin-1beta (IL-1beta) and hepatocyte growth factor (HGF) was measured in mice.

METHODS

Gastric mucosal lesions were induced in H. felis-infected BALB/c mice by water-immersion stress. The severity score of gastric erosions per stomach was measured as the sum of the length of erosions. Gene expression of IL-1beta and HGF were analyzed by Northern blot analysis and production of HGF was examined using the enzyme immunoassay method.

RESULTS

Water-immersion stress induced gastric mucosal lesions accompanied by increased expression of IL-1beta mRNA. H. felis infection evoked enhanced expression of IL-1beta and HGF genes. When H. felis-infected mice were stressed by water immersion, the mucosal lesions were more severe than those in non-infected mice. Moreover, IL-1beta gene expression as well as HGF production was further increased.

CONCLUSIONS

Although H. felis inoculation did not cause gastric mucosal erosions by itself, it augmented the stress-induced erosions.

Growth inhibitory effects of somatostatin on human leukemia cell lines mediated by somatostatin receptor subtype 1

Reverse transcription polymerase chain reaction analysis revealed that only somatostatin receptor (SSTR) 1 mRNA was expressed in Ball-1 B-, Jurkat T-, and HL60 leukemia cell lines. In contrast, human normal mononuclear cells expressed the mRNA of all five subtypes of SSTR, although the expression level of SSTR1 was the highest. A binding study, revealed that [125I]-somatostatin bound specifically to HL60 cells and this binding was inhibited concentration-dependently by unlabeled somatostatin (SS). A [3H]thymidine incorporation study showed that SS significantly and concentration-dependently inhibited HL60 and BALL-1 leukemia cell growth. Furthermore, this inhibition of leukemia cell growth was associated with reduces c-fos gene expression. These data indicate that leukemia cells express SSTR1 and SS reduce c-fos gene expression with resultant suppression of leukemia cell growth, possibly mediated by the SSTRI.

Patients view of the anaesthetist in a developing country

OBJECTIVE

The objective of this study was to assess patients regarding their knowledge and perception of the anaesthetists' role in patient care in a developing country.

SETTING

The audit was conducted at the Aga Khan University Hospital, Karachi.

METHODS

Two hundred surgical and 102 medical out-patients were included in the audit prospectively who filled a detailed questionnaire.

RESULTS

Fifty-six percent of the patients knew that anaesthetists were medically qualified but only 20% and 27% had an idea about their role in the intraoperative and immediate postoperative period. 14.6% were aware of the anaesthetists role outside the operating room. No difference was observed between the two groups of patients except that a higher percentage of surgical patients were interested in having more information regarding anaesthesia and wanted to choose their anaesthetist if the need arose. Gender difference was observed in answer to two questions only. A higher percentage of males know the role of anaesthetist in the recovery room whereas a greater number of females who had surgery before remembered their anaesthetist postoperatively.

CONCLUSION

The results of this audit show a poor perception of the anaesthetists role both inside and outside the operating room. Although public knowledge surveys have been carried out in developed countries there is a pressing need to repeat these in developing countries since the image as perceived by public may have a direct bearing on the recruitment of young doctors into an already shortage specialty in these less affluent countries.

Regenerating gene protein may mediate gastric mucosal proliferation induced by hypergastrinemia in rats

BACKGROUND & AIMS

Regenerating gene (Reg) has been isolated from rat regenerating pancreatic islets, and Reg protein is mitogenic to islet cells. We have recently shown that Reg gene and Reg protein are expressed in gastric enterochromaffin-like (ECL) cells. This study aimed to clarify whether gastrin enhances Reg protein production in ECL cells and whether Reg protein is mitogenic to gastric mucosal cells.

METHODS

Reg gene expression in response to acute and chronic hypergastrinemia was investigated in rats. Immunohistochemical studies, Northern blotting, and in situ hybridization were performed to investigate the expression of Reg protein and Reg gene. The direct effect of gastrin on Reg gene expression was investigated using isolated ECL cells, and the trophic effect of Reg protein on cultured gastric epithelial cells was assessed by [3H]thymidine uptake.

RESULTS

Both chronic hypergastrinemia and short-term gastrin administration stimulated Reg gene expression and Reg protein production in fundic mucosa. Reg gene expression was also augmented in isolated ECL cells after incubation with rat gastrin. Reg protein was mitogenic to cultured rat gastric epithelial cells.

CONCLUSIONS

Gastrin stimulates the production of Reg protein in gastric ECL cells, which may be involved in the gastrin-induced gastric mucosal cell growth.

Selective tracheal suctioning to prevent meconium aspiration syndrome

OBJECTIVE

To analyze the incidence and outcome of meconium aspiration syndrome (MAS) at Al-Yamamah Hospital, Riyadh, Saudi Arabia, where meconium-stained babies have intrapartum obstetrical cleansing of the upper airways, following which depressed/asphyxiated babies are intubated and vigorous babies are observed for 24 h.

METHOD

The total live births, records of meconium-stained neonates who had intubations and of those observed, during a 6-year period were reviewed.

RESULTS

During this period, there were 85562 live births. One in 325 births (0.27%) was complicated by MAS and the mortality rate was 7%. These figures concur with the reported incidence and mortality of MAS following routine combined obstetric-pediatric suction of airways at birth. Of the 265 cases of MAS that occurred during this period, 237 were in the intubated group and 28 in the observed group. The babies of the former group had severe disease compared with that of the latter. All mortality was from the intubated group.

CONCLUSION

Adequate obstetrical cleansing of the upper airway in vigorous babies may obviate the need for endotracheal intubation; intubation of depressed babies following this treatment may be useful.

Development and validation of a visual acuity chart for Australian Aborigines and Torres Strait Islanders

BACKGROUND

A new visual acuity chart was designed for use with Australia's indigenous population to overcome perceived inadequacies of conventional English letter charts for this group. This chart, which incorporates a black and white turtle icon, is described, and validation data are presented.

METHODS

The chart is based on logarithm of the minimum angle of resolution (logMAR) principles and incorporates a turtle symbol modified from the design of an indigenous artist. The task is one of discrimination, with subjects being required to distinguish the split tail of the turtle from its head, which has the same overall shape and average luminance; the body of the turtle provides no directional cues which might assist in this judgment. The chart was validated in two ways: Experiment I. Performance was compared with the Bailey-Lovie and Konig bar charts in terms of unaided visual acuity data for 90 subjects (mean age: 38.3 +/- 20.3 years) and Experiment II. Data were obtained for 10 young subjects for these 3 charts and an Illiterate E chart, with refractive blur imposed with trial lenses over habitual distance corrections (spherical: +0.50, +1.00, +2.00, and +4.00 D; cylindrical: +1.00 and +2.00 D, axes 45, 90, and 180 degrees). To avoid cultural and literacy issues as possible sources of differences in performance between the charts in this validation study, subjects were selected from the wider Australian population rather than specifically from its indigenous segment.

RESULTS

Experiment I: The Turtle chart performed most like the Konig Bar chart for this component of the validation exercise. Nonetheless, results for the Turtle chart correlated highly with those for the Bailey-Lovie chart as well as the Konig Bar chart, although there were subtle differences between charts in the rate of decline of visual acuity as visual performance decreased. Experiment II: The turtle chart behaved most like the Illiterate E chart with imposed spherical focusing errors, with the Bailey-Lovie chart showing a faster decline and the Konig Bar chart showing a slower decline in performance, with increasing defocus. All 4 charts showed similar directional biases with astigmatic defocus, being most affected by oblique (45 degrees) astigmatism.

CONCLUSION

The Turtle chart met the criteria set for its validation as a visual acuity chart in that it gave comparable results to the other commonly used visual acuity charts, both in the case of unaided vision and when refractive blur was imposed.

Extracorporeal shock wave lithotripsy for the rescue of post-endoscopic or surgically retained biliary duct stones: does saline irrigation affect the outcome?

Extracorporeal shock wave lithotripsy (ESWL) has been found valuable in situations where obstructing stones in the common bile or intrahepatic ducts are retained following surgery or attempted endoscopic removal. However, success rates are dependent on the type of ESWL system employed and upon a high frequency rate of repeated treatment sessions. We outline our experience with 23 cases of retained, obstructing bile duct stones, ranging in size from 10 to 40 mm diameter, treated with Dornier HM3 ESWL. In the initial 12 patients in the series, successful stone fragmentation occurred in 83% of cases with a median 1.6 treatment sessions. In the latter 11 cases in the series, patients were treated prone and the stone-bearing biliary duct was irrigated with saline solution during ESWL delivery. With this technique, successful stone break up was achieved in all patients (100%) with a single treatment session. Endoscopic sphincterotomy is, however, a prerequisite for extracorporeal lithotripsy and, despite the high success rates now available with new techniques, we believe the ESWL should continue to be employed in support of primary endoscopic methods of management for obstructing bile duct stones.

Relationship between severity and symptoms of reflux oesophagitis in elderly patients in Japan

Since information concerning reflux oesophagitis in the elderly is limited, particularly in Japan, the severity and symptomatic profiles of reflux oesophagitis in elderly patients were investigated. One hundred and nineteen patients with reflux oesophagitis found among 2278 endoscopy cases between 1993 and 1996 were investigated in this study. The patients were divided into two groups, elderly and non-elderly. The severity of reflux oesophagitis was estimated by the Los Angeles classification. The presence or absence of typical symptoms (heartburn and regurgitation) was determined by interview. Reflux oesophagitis was not only more frequently found in the elderly group, but was more severe than in the non-elderly. Although the degree of manifestation of typical symptoms was similar between the elderly and the non-elderly with high-grade oesophagitis, the elderly patients with mild reflux oesophagitis were less symptomatic than the non-elderly. Mild reflux oesophagitis in the elderly may be missed due to its rarity of typical reflux symptoms and a substantial number of elderly persons might have subclinical reflux oesophagitis.

Surgical treatment of acromio-clavicular dislocation

Acromio-clavicular joint (ACJ) dislocation usually occurs in young adults following trauma or sports injury. Fourteen patients underwent surgical treatment for symptomatic total ACJ dislocation (Rockwood and Matsen Type III-VI) in our unit between January 1996 and June 1997. Eight patients were operated within three weeks of injury and six in the chronic period (after three weeks). In the acute group, two patients had Botsworth procedure and six had Weaver-Dunn operations. All six in the chronic group had Rockwood procedure. Nine patients achieved excellent outcome with full range of shoulder movement, pain free and return to work within three months of surgery. Two patients had good outcome. Three other patients had satisfactory outcome with tolerable pain and light duty at three months. Two patients developed chronic shoulder pain and one had painful hypertrophic surgical scar. Two patients had screw breakage requiring revision surgery. In conclusion, surgical treatment for ACJ dislocation produces good results. We suggest that surgical treatment be the treatment of choice for young patients requiring early recovery and good shoulder function.

Geranylgeranylacetone, an anti-ulcer drug, stimulates hexosamine production in a rat gastric mucosal cell line through binding to a specific cytosolic protein

An anti-ulcer drug, geranylgeranylacetone (GGA), stimulates hexosamine production in a rat gastric mucosal cell line (RGM-1). The aim of this study was to elucidate the mechanism of this action. The role of protein kinase A, inositol phospholipid turnover and tyrosine kinase in the stimulatory action of GGA on hexosamine production in RGM-1 was determined by observing cAMP production, [3H]-inositol phosphate turnover and western blotting of tyrosine phosphorylation, respectively. Any trophic effect of GGA on RGM-1 was also checked by [3H]-thymidine incorporation. Our experiments showed that GGA has no effect on cAMP production, inositol phospholipid turnover, tyrosine phosphorylation or DNA synthesis in RGM-1. Finally, a [14C]-GGA competitive receptor binding assay was performed on RGM-1 and we found that [14C]-GGA specifically bound to RGM-1 cytosolic protein. Although retinoic acid (RA), another polyisoprenoid compound significantly stimulated hexosamine production in RGM-1, we confirmed that the [14C]-GGA binding site in RGM-1 is different from the RA binding site. In summary, GGA stimulates hexosamine production in RGM-1 and this action is probably mediated through its binding to a specific cytosolic protein in RGM-1.

Viscosity studies on Mestranol

The viscosity of 1x10(-4) M to 4x10(-4) M solution of Mestranol (synthetic oestrogenic steroidal hormone) in ethanol was measured at 32 degrees, 40 degrees and 50 degrees C in a viscometric bath. The viscosity rates are maximum at 30 degrees C as compared to 40 degrees and 50 degrees C. The disappearance rate of Mestranol at higher temperature and lower viscosity is due to triplet state of species transitions at higher thermal conditions.

Rat gastric mucosal cells express ICAM-1 and proinflammatory cytokines during indomethacin-induced mucosal injury

Adhesion molecules and cytokines are known to be involved in the formation of acute gastric mucosal injury. However, it is not clear whether the gastric mucosal cells express these molecules and modulate the inflammation. To clarify whether gastric mucosal cells express intercellular adhesion molecule-1 (ICAM-1) and proinflammatory cytokines (tumor necrosis factor-alpha (TNF-alpha), interleukin-1-alpha (IL-1-alpha), and cytokine-induced neutrophil chemoattractant-2-beta (CINC-2-beta)) in the formation of gastric mucosal injury, we have used rat indomethacin-induced gastric mucosal lesions as an in vivo model. The gene expression of all cytokines and ICAM-1 increases at the early stages of indomethacin-induced gastritis (TNF-alpha and IL-1-alpha gene expression began to increase earlier than that of ICAM-1 and CINC-2-beta) and can mainly be detected in the gastric epithelial layer. To further identify the source of those molecules, the epithelial cells were separated into seven fractions according to their sizes by a counterflow elution. ICAM-1 and CINC-2-beta gene expressions are particularly enhanced in the middle-sized cell fractions that are rich in gastric mucous-producing cells. The effect of TNF-alpha or IL-1-alpha on the gene expression of ICAM-1 and cytokines was examined by using RGM-1 cells as a model for gastric mucosal cells. RGM-1 cells show an augmented ICAM-1 and proinflammatory cytokine expression in response to TNF-alpha or IL-1-alpha stimulation. Moreover, immunohistochemical staining also reveals an increase in ICAM-1 and CINC protein production in RGM-1 cells in response to TNF-alpha stimulation. We conclude that gastric mucosal cells express various cytokines and an adhesion molecule during the formation of acute gastric mucosal injury and that they may modulate the inflammation.

Expression of protooncogene c-kit and its ligand stem cell factor (SCF) in gastric carcinoma cell lines

We examined 13 human gastric carcinoma cell lines for the expression of both c-kit and stem cell factor (SCF). Expression of mRNAs was detected by both Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR), and expression of translated proteins was detected by western blotting. Using RT-PCR we confirmed the expression of c-kit in five (ECC12, TMK1, MKN7, GCIY, and HGC27) cell lines. Northern blot analysis showed coexpression of both c-kit and SCF in ECC12 and expression of SCF in five other (MKN74, MKN1 OKAJIMA, KATOIII, and TMK1) cell lines. SCF stimulated both tyrosine phosphorylation of c-kit and growth of ECC12, whereas it did not stimulate those of GCIY. The sizes of c-kit transcript and protein in GCIY were slightly smaller than those of the reported ones, suggesting the presence of a biologically inactive truncated form of c-kit in GCIY. The present study suggests that c-kit/SCF system might play an important role in the carcinogenesis and tumor growth of ECC12 and that the truncated form of c-kit in GCIY might not be associated with malignant transformation.

Intragastric distribution of nonsteroidal anti-inflammatory drug-related ulcers in patients without collagen diseases

During the long-term administration of nonsteroidal anti-inflammatory drugs (NSAIDs), approximately 3% of patients have gastric ulcers develop in each year. Although much is known about the endoscopic characteristics of NSAID-induced gastric ulcers in patients with rheumatoid arthritis (RA), it is not clear where in the stomach NSAIDs induce ulcers in patients without RA. We looked at that question. During the 1-year study period, 29 patients with gastric ulcer, who had been taking NSAIDs regularly for more than 4 weeks mainly for osteoarthritis, were identified. Seventy-five patients with gastric ulcers who had not taken NSAID also were found. The sites of gastric ulcers of these two groups were quite different. The NSAID-induced ulcers mainly were found in the gastric antrum, whereas the majority of NSAID-unrelated ulcers were in the gastric corpus. We conclude that NSAID-induced ulcers in non-RA patients mainly are formed in the gastric antrum.

Helicobacter pylori induces proinflammatory cytokines and major histocompatibility complex class II antigen in mouse gastric epithelial cells

Although Helicobacter pylori has been reported to stimulate the release of various cytokines from gastric tissue, it remains unknown whether normal and nontumorous gastric epithelial cells produce these cytokines. Therefore, in this study, we used a normal mouse gastric surface mucous cell line (GSM06) to determine whether gastric epithelial cells produce proinflammatory cytokines in response to H. pylori. The expression of MHC class II antigen was also examined, to investigate whether gastric epithelial cells participate in the immune response to H. pylori. In the study, GSM06 cells were incubated with H. pylori or its lipopolysaccharide (LPS). Proinflammatory cytokines were detected by Northern and Western blot analysis. The expression of MHC class II antigen was examined by fluorescence activated cell sorter (FACS) analysis. Genetic expression of proinflammatory cytokines such as interleukin-1alpha, tumor necrosis factor-alpha, and cytokine-induced neutrophil chemoattractant-2beta was enhanced by both intact and sonicated H. pylori, but not by H. pylori LPS. The expression of MHC class II antigen was induced by H. pylori more strongly than by interferon-gamma. We conclude that H. pylori induces the expression of proinflammatory cytokines and MHC class II antigen in gastric epithelial cells. Gastric epithelial cells may act as antigen-presenting cells and participate in the immune response to H. pylori infection.

Expression of PTHrP, PTH/PTHrP receptor, and Ca(2+)-sensing receptor mRNAs along the rat nephron

To provide a frame of reference for studies of renal divalent cation and phosphate metabolism, we assessed the cellular localization of kidney calcium receptor (RaKCaR), parathyroid hormone-related protein (PTHrP), and parathyroid hormone/ parathyroid hormone-related protein (PTH/PTHrP) receptor mRNA. The studies used using reverse transcription-polymerase chain reaction (RT-PCR) applied to cDNA prepared from dissected rat nephron segments and from primary cultures of mouse juxtaglomerular granular cells. With species-specific primers, PCR products of expected size were obtained for RaKCaR (967 bp), PTHrP (420 bp), and PTH/PTHrP receptor (817 bp), with product identity being confirmed by restriction digestion. RaKCaR mRNA was found in medullary and cortical thick ascending limbs (MTAL and CTAL, respectively), the macula densa-containing segment, distal convoluted tubules (DCT), and, to a lesser extent, in cortical collecting ducts (CCD). It was not found in glomeruli, proximal convoluted and straight tubules (PCT and PST, respectively), outer and inner medullary collecting ducts (OMCD and IMCD, respectively), or in juxtaglomerular granular cell isolates. PTHrP mRNA was predominantly expressed in glomeruli and at lower levels in PCT and the macula densacontaining segment but was not detectable in CTAL, MTAL, DCT, and CD segments. Presence of PTH/PTHrP receptor mRNA was demonstrated in glomeruli, PCT, PST, CTAL, MTAL, and DCT but not in CD segments. These results suggest that the function of TAL and DCT cells, in addition to being affected by PTH, may be directly altered by extracellular divalent cations through RaKCaR and that PTHrP may act in the glomerulus and proximal tubule as an autocrine or paracrine regulator of hemodynamics and phosphate transport.

Distribution of prostaglandin E receptors in the rat gastrointestinal tract

AIMS

In order to study the role of prostaglandin in the regulation of the gastrointestinal functions, gene expression of prostaglandin receptors along the rat gastrointestinal tracts were investigated.

METHODS

Rats were used for the study. The combination of counterflow elutriation separation of mucosal cells and Northern blot analysis was used to detect the gene expression of prostaglandin receptors in gastrointestinal tracts.

RESULTS

In small intestine and colon, prostaglandin E2 EP1 and EP3 receptor mRNAs were mainly localized in the deeper intestinal wall containing muscle layers. EP4 receptor gene expression, on the other hand, was detected in the intestinal mucosal layer. In the stomach, EP1 mRNA was detected in gastric muscle layers, whereas EP3 and EP4 receptor gene expression was mainly present in the gastric mucosal layer containing epithelial cells. In gastric epithelial cells, parietal cells were found to have both EP3 and EP4 receptors. At lower concentrations, prostaglandin E2 inhibited gastric acid secretion by parietal cells probably through EP4 receptors. At higher concentrations, however, it stimulated it. On the other hand, mucous cells possessed only EP4 receptor mRNA.

CONCLUSIONS

Thus, it is suggested that prostaglandin E2 modulates gastrointestinal functions through at least three different prostaglandin receptors (EP1, EP3, and EP4), each of which has a distinct contribution in the gastrointestinal tract.