Pharmacologic agents inhibit rat mesangial cell proliferation and collagen synthesis

Prevention of the development of end-stage renal disease is one of the most promising areas of research in nephrology. Because mesangial cell proliferation and extracellular matrix accumulation have been regarded as antecedents of glomerulosclerosis, agents that can inhibit mesangial cell proliferation may have a potential to retard the progression of renal diseases. Therefore, we investigated several clinically available agents that might affect mesangial cell proliferation and collagen synthesis in male Sprague-Dawley rats. Cell proliferation was measured by the tetrazolium dye uptake method. Collagen synthesis was measured by 3H-proline incorporation into pepsin-resistant, salt-precipitated collagen. Intracellular cAMP levels were measured by enzyme immunoassay. Our results showed that hydralazine (82% inhibition at 10 micrograms/mL), ticlopidine (61% inhibition at 30 micrograms/mL), aminophylline (66% inhibition at 200 micrograms/mL), and nicametate (91% inhibition at 1 mg/mL) inhibited serum-stimulated rat mesangial cell (RMC) growth in a dose-dependent manner. Ticlopidine (43% inhibition at 30 mg/mL), aminophylline (52% inhibition at 200 mg/mL), and nicametate (35% inhibition at 1 mg/mL) inhibited collagen synthesis in confluent RMCs. Aminophylline may act through increasing intracellular cAMP levels (9.7 +/- 0.7 pmol/mg protein at 200 micrograms/mL of aminophylline vs 4.2 +/- 0.6 pmol/mg protein at control). These data suggest that aminophylline, ticlopidine, hydralazine, and nicametate can inhibit RMC proliferation and collagen synthesis.

An immunohistochemical study of E-cadherin expression with correlations to clinicopathological features in gastric cancer

BACKGROUND/AIMS

Reduced expression of E-cadherin leading to loss of cellular adhesion is crucial for cancer invasion and metastasis. The aim of this study is to investigate the role of E-cadherin in gastric tumorigenesis.

METHODOLOGY

Immunohistochemical expression of E-cadherin was analyzed and correlated with clinicopathological characteristics of 122 patients with gastric cancer.

RESULTS

Reduced E-cadherin expression was noted in 71 tumors (58.2%), while all normal epithelium showed a normal expression. Correlation of E-cadherin status to histological subtypes and growth patterns revealed a significantly higher frequency of reduced expression in diffuse type (46/60, 76.7%), advanced tumors (48/68, 70.6%) and stage III/IV (39/53, 73.6%) than that in intestinal type (25/62, 40.3%, p<0.0001), early tumors (23/54, 42.6%, p<0.005) and stage I/II (32/69, 46.4%, p<0.005) respectively. Moreover, abnormal expression was more frequent in tumors with positive lymph node metastasis (45/62, 72.6%), peritoneum seeding (10/11, 90.9%) and venous permeation (27/37, 73%) than that in tumors without lymph node metastasis (26/60, 43.3%, p<0.005), peritoneum seeding (61/111, 55.0%, p<0.05) and venous permeation (44/85, 51.8%, p<0.05). There is no statistical difference between E-cadherin expression and the status of perineural invasion or H. pylori infection. Analysis of survival for patients demonstrated that reduced E-cadherin expression was correlated with poor prognosis.

CONCLUSIONS

These data indicate that impaired expression of E-cadherin is an important characteristic of gastric cancer and contributes to histogenesis, tumor growth, metastasis and poor survival.

Gastric cancer risk in relation to Helicobacter pylori infection and subtypes of intestinal metaplasia

Helicobacter pylori (H. pylori) infection and intestinal metaplasia (IM) are each associated with an increased risk of gastric cancer (GC). To explore further the influences of H. pylori and IM on GC, H. pylori and subtypes of IM were evaluated in 135 sex and age-matched case and control pairs. Odds ratios (ORs) with 95% confidence intervals of developing GC were calculated for each risk factor using multiple logistic regression analysis. ORs for H. pylori infection and IM were 2.43 (1.29-4.65) and 4.59 (2.58-8.16), respectively, and those for different IM subtypes gave values of 0.82 (0.28-2.36) for type I, 2.03 (0.95-4.34) for type II and 39.75 (14.34-110.2) for type III. Stratification analysis by histological subtype and stage of GC showed a particularly high OR for IM in intestinal type (12.8, 4.73-34.83) and early GC (6.40, 2.25-18.18). Our data indicate that both H. pylori and IM are related to GC risk. Type III IM is a more specific marker of premalignancy, with relevance, in particular, to the early and intestinal type of GC.

Clinicopathological significance of altered loci of replication error and microsatellite instability-associated mutations in gastric cancer

Replication errors (RERs) judged by microsatellite instability and its associated mutations have been recognized as an important mechanism in tumorigenesis of gastric cancers (GCs). To gain a deeper insight into its significance, we examined the frequency of RERs using nine microsatellite markers and screened mutations in the polydeoxyadenine tract of the transforming growth factor beta type II receptor gene (TGF-betaRII) and polydeoxyguanine tracts of insulin-like growth factor II receptor and BAX genes. Twenty-four (30%) of 80 patients with GC had RERs, of which 3, 8, and 13 had one, two, and three or more loci, respectively. In 13 tumors with RERs in three or more loci, frameshift mutations of TGF-betaRII, insulin-like growth factor II receptor, and BAX were identified in 12, 3, and 2, respectively. Compared with GC with none, one or two RER-positive loci as a group, GC with RERs in three or more loci showed a significantly higher frequency of antral location (12 of 13 versus 35 of 67; P = 0.01), intestinal subtype (11 of 13 versus 30 of 67; P = 0.01), and previous Helicobacter pylori infection (12 of 13 versus 41 of 67; P = 0.05) and a lower incidence of lymph node metastasis (5 of 13 versus 49 of 67; P = 0.02) and tended to be in an advanced stage (12 of 13 versus 54 of 67; P = 0.28). These data indicate that GC with multiple RERs manifest distinct clinicopathological characteristics, and that a high frequency of frameshift mutations involving the TGF-betaRII gene may be causatively linked with tumorigenesis and progression.

Loss of pS2 protein expression is an early event of intestinal-type gastric cancer

To investigate the prevalence of pS2 expression in gastric cancer with respect to tumor histopathology, intestinal metaplasia and Helicobacter pylori (H. pylori) infection, pathologic specimens of 91 patients with gastric cancer were immunostained for pS2. Such immunoreactivity was correlated with the status of H. pylori infection, tumor staging, histology, subtyping, and associated intestinal metaplasia. Positive pS2 staining was seen throughout all non-neoplastic epithelia, and in all 9 patients with the complete type of intestinal metaplasia. In contrast, 21 of 45 incomplete type of intestinal metaplasia had negative pS2 staining (P < 0.001), and 54 out of 91 tumors (59.3%) showed loss of pS2 expression in the cancer tissues proper. There was no correlation of pS2 expression with age, gender, depth of invasion, duodenal involvement, lymph node metastasis, venous invasion or H. pylori infection. Negative pS2 staining was significantly higher in the intestinal (74.5%) and Borrmann type I, II, III (64.2%) tumors than the diffuse (43.2%, P < 0.005) and Borrmann type IV (20%, P < 0.05) tumors. Our results indicate that loss of pS2 expression may occur as an early event in the malignant transformation process of intestinal-type tumors.

Overexpression of mutant p53 and c-erbB-2 proteins and mutations of the p15 and p16 genes in human gastric carcinoma: with respect to histological subtypes and stages

Although the mechanism remains obscure, two histological subtypes of gastric carcinoma (GC), the diffuse and intestinal types, differ drastically in epidemiological, clinical, pathological and biological characteristics. We investigated whether the genetic alterations of several oncogenes and tumour suppressor genes could be correlated with the two histological subtypes. In 60 patients with GC, the overexpression of mutant p53 and c-erbB-2 oncoproteins was studied using immunohistochemical stains. Mutations of the p15 and p16 tumour suppressor genes were assessed by polymerase chain reaction, Southern blotting, and direct DNA sequencing. Overexpression of c-erbB-2 and p53 was found in 21 (35.0%) and 27 (45.0%) patients, respectively. Overexpression of the c-erbB-2 oncoprotein was more common in the intestinal type (15/32, 46.9%) and the advanced stage (19/45, 42.2%) than in the diffuse type (6/28, 21.4%) and the early stage (2/15, 13.3%) of GC (P<0.05). Similarly, p53 overexpression was more frequently found in the intestinal type (19/32, 59.4%) and the advanced stage (24/45, 53.3%) than in the diffuse type (8/28, 28.6%) and the early stage (3/15, 20.0%) of GC (P<0.05). Homozygous deletions of p16 in exon 1 were found in six (10.0%) patients. Five of them had the intestinal-type advanced GC. Neither point mutations of p16 nor alterations of p15 were detected. The frequency of alterations of p53, c-erbB-2, and p16 was not related to sex and Helicobacter pylori infection. No correlation of genetic changes between any two genes was observed. Our preliminary results indicate alterations in the p15 gene were not important in gastric tumorigenesis, while infrequent homozygous deletions in the p16 gene play a limited role in tumour progression of intestinal-type GC. Moreover, overexpression of c-erbB-2 and p53 is frequently encountered in the intestinal-type advanced GC. Alterations of p53, c-erbB-2 and p16 genes may function independently of each other in gastric carcinogenesis. The association between genetic alterations and histological subtypes supports the notion that a distinct pathogenesis may exist in different histological subtypes.

Superiority of interleukin-12-transduced murine lung cancer cells to GM-CSF or B7-1 (CD80) transfectants for therapeutic antitumor immunity in syngeneic immunocompetent mice

Interleukin-12 (IL-12) is a heterodimeric cytokine that consists of p40 and p35 subunits. IL-12 has been regarded as a potent inducer of host antitumor immunity through interferon-gamma (IFN-gamma) production and development of Th1 helper T cells from Th0 cells. Here, we demonstrate the immunomodulatory actions of an IL-12-transduced murine lung cancer cell line, Lewis lung carcinoma (LLC) (LLC/IL12) cells, in syngeneic C57BL/6 mice. We also report on their therapeutic potency. Three LLC/IL12 cells producing different levels of IL-12 were cloned and found to have diminished tumorigenicity in C57BL/6 mice depending on their level of IL-12 production. In vivo depletion assay demonstrated that the loss of tumorigenicity of LLC/IL12 depended on both CD4+ and CD8+ T cells, and that natural killer (NK) cells were involved, especially in the early phase of immunity. The strong systemic antitumor immunity against challenge with wild type LLC (LLC/wt) cells was also induced by LLC/IL12 cells. The systemic antitumor memory was found to be dependent mainly on the CD4+ T-cell subset. 51Cr-release assay revealed that the killer activity consisted of a specific killer activity directed at the parental LLC/wt cells and a nonspecific killer activity directed at both LLC/wt and syngeneic EL-4 thymoma cells. In addition, LLC/IL12 apparently had a much stronger antitumor effect against the established LLC/wt tumor than LLC transduced with B7-1 or GM-CSF cDNA. IL-12 can be considered an efficient candidate molecule for immunogene therapy for lung cancer in this experimental system.

Theoretical investigation of the SAW properties of ferroelectric film composite structures

The characteristics of surface acoustic waves (SAW) propagating on a three-layered structure consisting of a perovskite-type ferroelectric film, a buffer layer and a semiconductor substrate have been studied theoretically. Large coupling coefficients (K(2)) can be obtained when the interdigital transducer (IDT) is on top of the perovskite-type ferroelectric film, with (type 4) and without (type 3) the floating-plane electrode at the perovskite-type ferroelectric film-buffer layer interface. In the above cases, the peak values of K (2) Of the Pb(Zr,Ti)O(3) (PZT) films (3.2%-3.8%) are higher than those of the BaTiO(3) (BT) and PbTiO(3) (PT) films. In the IDT configuration of type 4, there exists a minor peak of the coupling coefficients for the PZT and BT films, but not for the PT films when the normalized thickness (hK) of the perovskite-type ferroelectric film is about 0.3. The minor peak values of the coupling coefficients (0.62%-0.93%) for different layered structures (PZT/STO/Si, PZT/MgO/Si, and PZT/MgO/GaAs) all decrease when we increase hK value from 0 to 0.25. The results could be useful in the integration of ferroelectric devices, semiconductor devices, and SAW devices on the same substrate.

Glomerular transforming growth factor-beta1 mRNA as a marker of glomerulosclerosis-application in renal biopsies

As transforming growth factor-beta1 (TGF-beta1) is implicated in the pathogenesis of glomerulosclerosis, the aim of the study was to demonstrate if levels of glomerular TGF-beta1 mRNA in renal biopsies correlated with glomerulosclerosis. Glomeruli were collected by microdissection from renal biopsies in patients with membranous nephropathy, lupus nephritis, diabetic nephropathy, minimal change disease and IgA nephropathy presented by proteinuria when serum creatinine was <3 mg%. Glomerular mRNAs were reverse transcribed and TGF-beta1, alpha2(IV) collagen, beta-actin cDNA quantitated by competitive polymerase chain reaction (PCR). By semiquantitative electron microscopy, a 3.5-fold increase of glomerular TGF-beta1/beta-actin mRNA ratio in the moderate sclerotic group (n = 23, p < 0.01) and a 1.5-fold increase in the mild sclerotic group (n = 22, p < 0.05) were observed when compared to the minimal sclerotic group (n = 12). A concordant increase of glomerular alpha2(IV) collagen mRNA was found with 2.2- and 1.3-fold in moderate and mild sclerotic groups, respectively. The TGF-beta1/beta-actin mRNA ratios were highest in membranous nephropathy (466.4 +/- 133.4, n = 11), followed by lupus nephritis (394.9 +/- 94.8, n = 12) and diabetic nephropathy (333.2 +/- 97.6, n = 10). Patients with minimal change disease(233.1 +/- 54.1, n = 15)and IgA nephropathy(185.3 +/- 39.6, n = 9) had low levels. The degree of glomerulosclerosis in each group followed the TGF-beta1/beta-actin mRNA ratios indicating that the level is the major determinant ofglomerulosclerosis but not the disease entities. Glomerular TGF-beta1/beta-actin mRNA ratio did not correlate with clinical parameters such as the urinary protein excretion and creatinine clearance. These results suggest that glomerular TGF-beta1/beta-actin mRNA ratio may be used as a marker of glomerulosclerosis in renal biopsy to reflect the local sclerotic process.

Distinct clinicopathologic characteristics of diffuse- and intestinal-type gastric cancer in Taiwan

The clinicopathologic features of 221 patients with intestinal-type (IT) gastric cancer were compared retrospectively with those of 290 diffuse type (DT). Intestinal type was characterized by an older mean age (65.0 +/- 10.8 years vs. 56.2 +/- 13 years), a higher male-female ratio (2.56 vs. 1.06), predominance of blood group O (46.2% vs. 31.1%), and frequent habitual smoking (50.7% vs. 31.4%) and drinking (28.5% vs. 17.6%) than did DT. In contrast, DT had a higher frequency of positive history of parent or sibling with gastric cancer (9.3% vs. 4.1%) and blood group A (40.3% vs. 27.6%) than did IT. The distinguishing histologic features of DT included more Borrmann type IV (13.1% vs. 1.3%) but less Borrmann type I (1% vs. 7.2%), more frequent involvement of middle third (26.9% vs. 15.9%) and whole stomach (4.1% vs. 0%), and more peritoneal seeding (15.5% vs. 9%), lymph node metastasis (67.2% vs. 51%), and nerve permeation (34.1% vs. 24.4%), but less Helicobacter pylori infection (55.9% vs. 69.2%) when compared with those of IT. There was no difference in depth of tumor invasion, venous permeation, duodenal involvement, and postoperative survival between IT and DT. These distinct clinicopathologic features between IT and DT in Taiwan suggest the presence of a different pathogenic process for these two histologic subtypes of gastric cancer.

Leptospirosis: an ignored cause of acute renal failure in Taiwan

Leptospirosis, caused by a spirochete, is the most common zoonosis in domestic or wild animals. Animals excrete infected urine in soil or water and may cause human infections through abrased wound, mucosa, conjunctiva, or by swallowing contaminated water. Clinical presentations of leptospirosis are mostly subclinical. Five to ten percent of leptospirosis are fatal, causing fever, hemorrhage, jaundice, and acute renal failure (Weil's syndrome). Leptospirosis has been ignored as a cause of acute renal failure in Taiwan. We report two patients with leptospirosis who presented with high fever, abdominal pain, jaundice, and acute renal failure. Patient 1 died on day 12 of admission of multiple organ failure associated with pancytopenia, hypogammaglobulinemia, and reactive hemophagocytosis. Leptospirosis was recognized after death. Patient 2 was admitted with similar presentations 2 weeks later. Penicillin and doxycycline were given early in the course, and azotemia, jaundice, respiratory failure, and aseptic meningitis gradually improved. Renal biopsy showed interstitial nephritis. Several tubular clearance tests showed proximal tubular defect with severe bicarbonate wasting (FeHCO3- 20.9%) and incomplete type II renal tubular acidosis without affecting the distal nephron. After 80 days of treatment, this patient was discharged with recovery of conscious level and renal function. This is the first leptospirosis patient with detailed tubular functional and morphological studies of the kidney. Diagnosis of leptospirosis was made by microscopic agglutination test (MAT) for antibody to leptospira and by polymerase chain reaction (PCR) for leptospira DNA in blood and urine (interrogans serogroup australis in case 1 and Leptospira borgpetersenii serogroup ballum in case 2). Because active surveillance has resulted in 13 cases diagnosed as leptospirosis islandwide thereafter, underestimation and ignorance of leptospirosis as a cause of acute renal failure may occur in Taiwan. Therefore, an area with a low leptospirosis incidence may actually have a very high incidence. Leptospirosis should be suspected in febrile patients with jaundice and renal failure when pathogens cannot be identified by traditional culture for microorganisms.

Loss of imprinting and overexpression of IGF2 gene in gastric adenocarcinoma

Both insulin-like growth factor II (IGF2) and H19 gene are located on chromosome 11p15.5 in close vicinity to each other, and are imprinted on different parental alleles. Although the exact mechanism remains unclear, loss of imprinting (LOI) leading to the biallelic expression of IGF2 and H19 genes has recently been reported in a variety of tumors. To study the role of IGF2 and H19 genes in gastric carcinogenesis, the LOI and loss of heterozygosity (LOH) status of these two genes were determined in 70 patients with gastric cancer. Among them, 30 patients were heterozygous for IGF2, 28 patients were heterozygous for H19, and 42 patients were heterozygous for either IGF2 or H19 gene. Among the 30 patients who were heterozygous for IGF2, one exhibited LOH (1/30, 3.3%) and 10 exhibited LOI (10/29, 34.5%). None of the 28 patients heterozygous for H19 gene had either LOH or LOI. LOI of IGF2 was more frequently found in the diffuse type (8/15, 53.3%) than the intestinal type (2/14, 14.3%, P < 0.05) gastric cancer. Five out of the six tumors with LOI of IGF2 exhibited overexpression of mRNA, but no obvious alterations of expression of H19 were noted by Northern hybridization. These data suggest that LOI leading to overexpression of IGF2 plays an important role in carcinogenesis of diffuse type gastric cancer.

Attenuated response of renal mechanoreceptors to volume expansion in chronically hypoxic rats

Multifiber renal afferent nerve activity responds to volume expansion in sea level rats but not in chronically hypoxic (high altitude) rats. We performed single-unit recordings of renal afferent nerve activity to characterize renal sensory receptors and their responses to volume expansion in these animals. Hypoxia was induced by placing Wistar rats in an altitude chamber (380 Torr, 5,500 m) for 4 wk. Spontaneously firing renal R2 chemoreceptor and arterial, ureteropelvic, and venous mechanoreceptors were identified. The basal activity of each receptor was similar among these rats. In response to specific stimulus, the increasing impulse of R2 chemoreceptor was similar between two groups of rats, but the increasing activity of each mechanoreceptor was less in hypoxic rats. When challenged with saline load, R2 chemoreceptor activity decreased, but all mechanoreceptors activated in all rats. Despite similar increases of arterial, renal ureteropelvic, and venous pressure during saline load, the increasing activity of each mechanoreceptor was significantly less in hypoxic rats. These results indicated chronic hypoxia attenuates the sensitivity of renal mechanoreceptors in response to the stimulation of saline load.

Poor pre-dialysis glycaemic control is a predictor of mortality in type II diabetic patients on maintenance haemodialysis

BACKGROUND

In type II diabetic patients, a better glycaemic control has been reported to slow down the progression of nephropathy. The effect of pre-dialysis glycaemic control on the long term prognosis in type II diabetics on haemodialysis is still uncertain. The purpose of this study is to evaluate the effect of glycaemic control before starting maintenance haemodialysis on the clinical outcome in type II diabetic haemodialysis patients.

METHODS

One hundred and thirty-seven type II diabetics receiving regular haemodialysis in a single university hospital were enrolled. The patients were classified as either good or poor glycaemic control group according to their glycaemic control within 6 months before starting haemodialysis. Serum albumin, haematocrit, cholesterol, triglyceride, residual renal function, diabetic complications, and patient survival were analysed in both groups.

RESULTS

There was no significant difference in age, gender, predialysis albumin level, cholesterol level, triglyceride level, and residual renal function between the two groups. The 1-year (94.5% vs 80.0%), 3-year (82.9% vs 58.1%), and 5-year (75.8% vs 21.8%) cumulative survival rates were lower in the poor glycaemic control group than in the good glycaemic control group (P < 0.001). The poor glycaemic control group also had more cardiovascular morbidity during the period of dialysis (P < 0.001). The increase in cardiovascular complications also accounted for the increased mortality during the course of haemodialysis.

CONCLUSIONS

We conclude that poor glycaemic control before starting dialysis is a strong predictor of cardiovascular morbidity and survival for type II diabetics on haemodialysis. These results imply that better glycaemic control before dialysis might be important in improving the long-term prognosis in type II diabetics on haemodialysis.

Hepatitis B vaccine in hemodialysis patients with hepatitis C viral infection

Patients on hemodialysis therapy are at a relatively high risk of exposure to hepatitis B virus (HBV) infection. The prevalence of hepatitis C virus (HCV) infection is even higher and was reported as 33.2% in Taiwan. Although the efficacy of hepatitis B vaccine was well documented, the vaccination schedule in hemodialysis patients is not clearly defined. And under such a high prevalence of HCV infection, little is known about the influence of HCV imposing on HBV vaccination. We studied 50 chronic hemodialysis patients who were serologically negative for the hepatitis B surface antigen (HBsAg), the antibody to the hepatitis B surface antigen (anti-HBs) and the antibody to the hepatitis B core antigen (anti-HBc); 26 of them were positive for the antibody to hepatitis C virus (anti-HCV) test. Recombinant hepatitis B vaccine (Engerix-B) 40 micrograms per dose was administered by the intramuscular route at deltoid region at 0, 1, 2, 6 and 12 months respectively to all the patients. Forty-six patients had completed the study. The effective seroconversion rate (serum anti-HBs titer > 10 mIU ml-1) at 1 month after the final vaccine was 76.1% (35/46). The effective conversion rates of the anti-HCV(+) group to the anti-HCV(-) were 75% versus 77.3% (P = 0.857). Geometric mean anti-HBs titers were 177.67 mIU ml-1 versus 189.28 mIU ml-1 (P = 0.867). Our results showed that five-dose injections of HBV vaccine do not present a superior outcome to the four-dose regimen comparing to published data. The status of positivity of anti-HCV do not pose an suboptimal effect on HBV vaccination of hemodialysis patients.

Renal function of substance P in rats chronically exposed to hypoxia

BACKGROUND

We studied the renal action of substance P (SP) in rats chronically exposed to hypoxia (high altitude, HA), compared to control rats kept at sea level (SL).

METHODS

Hypoxia was induced by placing female Wistar rats (182-225 g) in an altitude chamber (5500 m) 15 h.d-1 for 4 weeks.

RESULTS

Intrarenal arterial infusion of substance P (60 ng.kg-1. h-1) increased the excretion of urine, sodium in both groups of rats, however, the excretion of kallikrein (KK) and the glomerular filtration rate (GFR) were not significantly altered. After aprotinin (10,000 kiu.kg-1. min-1) treatment, kallikrein was depleted, and substance P lost its diuretic action. Spantide, an SP antagonist (6000 ng.kg-1. h-1, I.V.) decreased urine, and urinary excretion of sodium and potassium in SL rats, but not in HA rats. Acute renal denervated diuresis in SL rats was not modified after Spantide administration. Finally, it was found that both SP and SP antagonist did not significantly change the renal parameters in either group of rats after chronic renal denervation.

CONCLUSION

We made the following conclusions: a) endogenous renal action of SP was suggested in SL but not in HA rats; b) the renal action of SP might be through KK release, although urinary KK did not increase after SP administration; and c) SP action is renal nerve dependent in both groups of rats.

Timed appearance of lymphocytic choriomeningitis virus after gastric inoculation of mice

Arenaviruses present an emerging health threat in agrarian areas of Africa and South America; however, the natural routes of arenaviral infections are not clearly understood. Our previous studies with lymphocytic choriomeningitis virus (LCMV), the prototype arenavirus, implicate oral and intragastric routes as natural routes of infection. Our studies raised many questions about the primary site of infection and the route of dissemination after gastric infection. In this report, we use in situ hybridization to detect LCMV in various organs at different time points (0 to 96 hours). After gastric inoculation, the gastric mucosa is the initial site of viral infection, followed by infection of the spleen and liver, then ileum and last, lung, kidney, brain, and esophagus. Furthermore, our observations suggest that virus is disseminated lymphatically rather than by a hematogenous route. Infectious center assays using mononuclear cells from stomach, blood, and spleen of mice infected by the gastric route confirmed active infection with LCMV and the presence of mononuclear cells producing infectious virus in these tissues. This is the first identification of gastric epithelia as a primary site of virus infection.

Renal R2 chemoreceptor activity is attenuated after back heating in the rat

Recent study in our laboratory has found that renal afferent nervous activity (RANA) was decreased during and after 42 degrees C back heating (BH). To investigate which renal sensory receptor is influenced during and after BH, a C-shaped glass heating pad (42 degrees C) was used on the skin of the back overlying the kidneys. A single-unit recording was used to identify four types of renal sensory receptors, the R2 chemoreceptor (CR2), arterial mechanoreceptor (MRa), ureteropelvic mechanoreceptor (MRu) and venous mechanoreceptor (MRv) in anesthetized female Wistar rats. Renal cortical microvascular blood flow (CMBF) and urinary water, potassium and sodium output were measured. It was found that CR2 activity was significantly decreased during and after BH, but three types of MRs were not altered. CMBF and urine output were significantly increased during and after BH. It is concluded that the increase in renal hemodynamics by BH may dilute some chemicals in the kidney and decrease the firing rate of R2 chemoreceptors.

Increased prevalence of Helicobacter pylori infection among patients affected with intestinal-type gastric cancer at non-cardiac locations

Previous data on the association of Helicobacter pylori infection with gastric cancer by demographic or histological features are inconsistent due to a univariate analysis of limited case numbers. The aim of the present study was to determine such an association by the use of a large series of patients and multiple variables analysis. The serum IgG antibodies against H. pylori were measured in 397 patients with histologically verified gastric cancer. A multiple logistic regression analysis was used to define the association between seropositivity and demographic or tumour characteristics of gastric cancer. The overall seropositivity of H. pylori was 63%. In univariate analysis, the prevalence was significantly lower among patients with cardia (50%) or diffuse-type (56.6%) cancers than those with non-cardia (64.8%) or intestinal-type (70.3%) cancer (P < 0.05 and P < 0.01, respectively). There was no statistical difference between H. pylori infection rate and gender, age or tumour stage. A multiple logistic regression analysis showed tumour location and histology remained significant factors associated with seropositivity of H. pylori with an odds ratio of approximately 2.0. Analysis of combined histology and location revealed that patients with intestinal-type cancer at non-cardia locations had the highest odds ratio of 3.93 (95% confidence interval (CI): 1.55-10.0) compared with the lowest odds ratio of 0.69 (95% CI: 0.30-1.62) in diffuse cardia cancer (P < 0.005). Our data indicate H. pylori infection in gastric cancer is independently affected by the histological subtype and by tumour location.

Genetic alterations in gastric cancer: relation to histological subtypes, tumor stage, and Helicobacter pylori infection

BACKGROUND & AIMS

A different spectrum of genetic changes including p53, c-erbB-2, c-met, adenomatous polyposis coli (APC), and deleted in colorectal cancer (DCC) is involved in gastric cancer (GC). The aim of this study was to correlate these alterations with histological subtypes, tumor stages, and Helicobacter pylori infection.

METHODS

Specimens of 163 patients with GC were immunostained for p53, c-erbB-2, and c-met, and polymerase chain reaction was performed in them to determine loss of heterozygosity (LOH) of APC and DCC.

RESULTS

Overexpression of p53 was more frequent in early intestinal than early diffuse GC and was noted in the stage progression of diffuse but not intestinal GC. Overexpression of c-erbB-2 occurred more commonly in intestinal GC and advanced GC of both types. Overexpression of c-met was greater in diffuse GC, particularly at advanced stage. LOH of APC was more common in intestinal GC irrespective of the stage but rarely in diffuse GC. LOH of DCC occurred primarily in advanced intestinal GC and infrequently in early GC or advanced diffuse GC. Alterations of these five genes were not correlated with H. pylori infection.

CONCLUSIONS

A distinct genetic pathway exists in gastric carcinogenesis of different histological subtypes and their tumor progression, in which H. pylori infection may play an equal role or no role.

Predialysis glycemic control is an independent predictor of clinical outcome in type II diabetics on continuous ambulatory peritoneal dialysis

OBJECTIVE

To evaluate the correlation between predialysis glycemic control and clinical outcomes for type II diabetic patients on continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

Sixty type II diabetic patients on CAPD were classified into 2 groups according to the status of glycemic control. In group G (good glycemic control), more than 50% of blood glucose determinations were within 3.3-11 mmol/L and the glycosylated hemoglobin (HbA1C) level was within 5-10% at all times. In group P (poor glycemic control), fewer than 50% of blood glucose determinations were within 3.3-11 mmol/L or HbA1C level was above 10% at least once during the follow-up duration. In addition to glycemic control status, predialysis serum albumin, cholesterol levels, residual renal function, peritoneal membrane function, and the modes of glycemic control were also recorded.

SETTING

Dialysis Unit, Department of Nephrology of a single university hospital.

PATIENTS

From February 1988 to October 1995, 60 type II diabetic patients receiving CAPD for at least 3 months were enrolled.

MAIN OUTCOME MEASURES

Morbidities before and during the dialysis period, patient survival, and causes of mortality.

RESULTS

The patients with good glycemic control had significantly better survival than patients with poor glycemic control (p < 0.01). There was no significant difference in predialysis morbidity between the two groups. No significant differences were observed in patient survival between the patients with serum albumin greater than 30 g/L and those with less than 30 g/L (p = 0.77), with cholesterol levels greater or less than 5.18 mmol/L (p = 0.73), and with different peritoneal membrane solute transport characteristics evaluated by peritoneal equilibration test (p = 0.12). Furthermore, there was no significant difference in survival whether the patients controlled blood sugar by diet or with insulin (p = 0.33). Cardiovascular disease and infection were the major causes of death in both groups. Although good glycemic control predicts better survival, it does not change the pattern of mortality in diabetics maintained on CAPD.

CONCLUSIONS

Glycemic control before starting dialysis is a predictor of survival for type II diabetics on CAPD. Patients with poor glycemic control predialysis are associated with increased morbidity and shortened survival.

Seroprevalence of Helicobacter pylori in patients with surgical peptic ulcer

BACKGROUND

Helicobacter pylori is known as a major cofactor in ulcerogenesis. However, the role of H pylori in surgical patients with peptic ulcer and its possible influence on surgical treatment is unclear.

OBJECTIVES

To determine the prevalence of H pylori infection in surgical patients with complicated peptic ulcer diseases and analyze its clinical significance.

DESIGN

A prospective, controlled study.

SETTING

University-affiliated hospital and tertiary care center.

SUBJECTS

Two study groups: surgical group (n = 66), i.e., patients who received surgical treatment for their peptic ulcer disease), and control group (n = 377) comprising 3 subgroups: normal volunteers (NV subgroup, n = 136) and patients who required only medical treatment for duodenal ulcer (DU subgroup, n = 119) or gastric ulcer (GU subgroup, n = 122) from January 1, 1994 to June 30, 1995.

METHODS

Preoperative or overnight fasting serum samples were collected, and H pylori state was assessed by serum anti-H pylori IgG.

RESULTS

Seropositivity was similar between the surgical group (60.6%) and NV control subgroup (58.8%), but it was highest in the DU control subgroup (87.4%) (P < .001 compared with NV control subgroup), followed by GU control subgroup (76.2%) (P < .01 compared NV). The patients with surgical peptic ulcer who had both seropositive and seronegative results for H pylori were similar for sex, age, social status, ulcer history, associated major medical problems, use of nonsteroid anti-inflammatory drugs, ulcer location, type of surgery, and ulceration recurrence rate. Although patients who underwent elective surgery had a higher seroprevalence rate (88.9%) than those requiring emergency surgery (56.4%) and patients who were seronegative for H pylori seemed to be associated with a higher major morbidity, these results were not statistically significant.

CONCLUSION

No significant association of H pylori infection and peptic ulcer was noted between patients who required surgical treatment compared with those who required only medical treatment; H pylori played only a limited role in the cause of disease in surgical patients, perhaps only in the cases complicated with stenosis or intractable ulcers. This suggests that presently adequate acid reduction procedure will still be the main objective of surgical treatment and prevention of the ulcer recurrence.

Relationship of p53 and c-erbB-2 expression to histopathological features, Helicobacter pylori infection and prognosis in gastric cancer

BACKGROUND/AIMS

Conflicting results concerning the relationships between abnormal expression of p53 and c-erbB-2 and biologic behavior of gastric cancer are noted. Therefore, overexpression of p53 and c-erbB-2 in relation to the following aspects of gastric cancer: tumor histopathology, Helicobacter pylori infection, and prognosis are explored.

MATERIALS AND METHODS

Expression of p53 and c-erbB-2 by immunohistochemistry was correlated with histopathology, H. pylori infection and prognosis of gastric cancer in 112 patients.

RESULTS

Positive p53 staining was found in 61 (54.5%) of 112 tumors examined. There was no association of p53 expression with sex, age, lymph node metastasis, H. pylori infection or prognosis. A significantly higher frequency of p53-positive staining was observed in advanced (60.7%), intestinal (69.8%) and cardia (76.5%) than in early (30.4%, p < 0.01), diffuse (34.7%, p < 0.01) and noncardia (50.5%, p < 0.05) carcinoma, respectively. Expression of c-erbB-2 was found in 34 cases (30.3%), and was not related to sex, age, H. pylori infection and tumor location. Tumors with positive c-erbB-2 staining appeared to behave more aggressively in view of higher rates of nodal metastasis (38.0% vs 17.1%, p < 0.05), advanced stage (37.1% vs 4.3%, p < 0.01) and poor mean survival (p < 0.01). Patients with intestinal type tumors also had a significantly higher rate of c-erbB-2 expression than those with diffuse tumors (39.7% vs 18.4%, p < 0.01).

CONCLUSIONS

Our results indicate that immunohistochemical expressions of p53 and c-erbB-2 are significantly associated with some histopathological phenotypes. Genetic alterations of c-erbB-2 or p53 may not be affected by H. pylori infection. C-erbB-2 expression may be used as a marker for identifying more aggressive gastric cancer for designing further therapy.

Infrequent hMSH2 mutations in sporadic gastric adenocarcinoma with microsatellite instability

The status of genetic instability was determined with seven microsatellite markers from 40 patients with primary gastric adenocarcinoma. For those cases with microsatellite instability, alterations of hMSH2 were further investigated by direct sequencing of reverse transcription-polymerase chain reaction products. Twelve (30%) of 40 patients were found to have microsatellite instability. Among them, one patient (1/6, 16.7%) was early gastric cancer and 11 (11/34, 32.4%) were advanced gastric cancer. There were seven patients with diffuse type (7/18, 38.7%), while five (5/22, 22.7%) were intestinal type tumors. The entire coding region of the hMSH2 gene in these 12 affected individuals was amplified and sequenced. Only a 41-year-old female patient with diffuse type advanced gastric cancer showed a GCT to TCT missense mutation at codon 207 with predicted protein change from alanine to serine. Our results indicate that genetic instability plays an important role in gastric tumorigenesis and alterations of the hMSH2 gene are related to only a small portion of sporadic gastric adenocarcinoma with microsatellite instability.