Discretized diffusion processes

We study the properties of the "rigid Laplacian" operator; that is we consider solutions of the Laplacian equation in the presence of fixed truncation errors. The dynamics of convergence to the correct analytical solution displays the presence of a metastable set of numerical solutions, whose presence can be related to granularity. We provide some scaling analysis in order to determine the value of the exponents characterizing the process. We believe that this prototype model is also suitable to provide an explanation of the widespread presence of power law in a social and economic system where information and decision diffuse, with errors and delay from agent to agent.

Adaptive response of thymocyte apoptosis and cell cycle progression induced by low dose X-ray irradiation in mice

The dose-effect of adaptive response of thymocyte apoptosis and cell cycle progression induced by whole-body X-ray irradiation (WBI) was studied in male Kunming mice. The inductive doses (D1) were 25, 50, 75, 100 or 200 mGy 6 h before the challenging doses (D2) of 1.0, 1.5 or 2.0 Gy. The changes in the percentages of the thymocyte apoptotic bodies (TAB) and the cells in different phases of cell cycle were measured with flow cytometry. The percentages of TAB decreased, the arrests of G1 and G2 + M phases diminished, and the cells of DNA synthesis of S phase increased when the D1 + D2 groups was compared with the D2 groups. When D1 was 200 mGy, the adaptive response of thymocyte apoptosis and cell cycle progression were no longer induced by low dose radiation (LDR). In addition, the extracellular fluid from the splenocytes were cultured with Con A for 48 h in vitro 24 h after 75 mGy WBI was placed in the murine thymocyte suspension from mice irradiated with 2.0 Gy WBI and co-incubated. The thymocyte apoptosis decreased. Especially, noteworthy was that the percentages of TAB after the incubation for 72 h were significantly lower than those in 2.0 Gy irradiated thymocytes (P < 0.05). These results indicate that when the mice were irradiated with 25-100 mGy (D1, 12.5 mGy/min) 6 h before 1.0-2.0 Gy (D2, 0.287 Gy/min) exposure, an adaptive response of thymocyte apoptosis and cell cycle progression may be induced under the condition of WBI, and LDR (75 mGy) may change the microenvironment of immune cells and decrease the thymocyte apoptosis.

Protection against myocardial dysfunction induced by global ischemia-reperfusion by antisense-oligodeoxynucleotides directed at beta(1)-adrenoceptor mRNA

Plasma catecholamine levels rise, and myocardial beta(1)-adrenoceptor (beta(1)-AR) sensitivity increases during ischemia. These factors enhance myocardial injury and cardiac dysfunction. beta(1)-AR blockers are clinically used to protect heart against ischemia and to improve cardiac dysfunction in patients with ischemic heart disease, but these agents often cause intolerable side effects. To examine the potential cardioprotective effect of therapy with antisense-oligodeoxynucleotides directed at beta(1)-AR mRNA (beta(1)-AS-ODNs) during myocardial ischemia-reperfusion, Sprague-Dawley rats were treated with beta(1)-AS-ODNs or inverted-oligodeoxynucleotides (IN-ODNs), each 200 microg/rat. Hearts were excised, perfused, and subjected to global ischemia (30 min) followed by reperfusion (30 min). Other rats were given selective beta(1)-AR blocker atenolol (2 mg/kg) or saline before excising the hearts. Ischemia-reperfusion resulted in cardiac dysfunction, indicated by an increase in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in developed left ventricular pressure, as well as evidence of lipid peroxidation in saline-treated rats (all P <.05 versus control values). Administration of AS-ODNs or atenolol, but not IN-ODNs, protected hearts against functional deterioration and lipid peroxidation (P <.05 versus saline or IN-ODNs treatment). AS-ODNs therapy appeared to be equivalent to atenolol in these effects. Expression of beta(1)-AR protein as well as mRNA in the myocardium were markedly up-regulated after ischemia-reperfusion, and treatment with beta(1)-AS-ODNs, but not atenolol, decreased the rise in enhanced expression of beta(1)-AR. These observations imply that beta(1)-AS-ODNs can ameliorate cardiac dysfunction after ischemia-reperfusion by reducing the expression of beta(1)-AR in the ischemic-reperfused myocardium.

Ultrastructure of the post-corpus of Zeldia punctata (Cephalobina) for analysis of the evolutionary framework of nematodes related to Caenorhabditis elegans (Rhabditina)

The ultrastructure of the post-corpus of Zeldia punctata (Cephalobina) was compared with previous observations of Caenorhabditis elegans (Rhabditina) and Diplenteron sp. (Diplogastrina) with the goal of interpreting the morphological evolution of the feeding structures in the Secernentea. The post-corpus of Z. punctata consists of six marginal, 13 muscle, five gland and seven nerve cells. The most anterior of four layers of muscle cells consists of six mononucleate cells in Z. punctata. The homologous layer in C. elegans and Diplenteron consists of three binucleate cells, suggesting a unique derived character (synapomorphy) shared between the Rhabditina and Diplogastrina. Contrary to Diplenteron sp. where we observed three oesophageal glands, Z. punctata and C. elegans have five oesophageal glands. We question this shared character as reflecting a common evolution between the Cephalobina and Rhabditina, because there are strong arguments for functional (adaptive) convergence of the five glands in these bacterial feeders. Convergence is further suggested by the mosaic distribution of three versus five glands throughout the Nemata; this distribution creates difficulties in establishing character polarity. Although morphological data are often laborious to recover and interpret, we nevertheless view 'reciprocal illumination' between molecular and morphological characters as the most promising and robust process for reconstructing the evolution of the Secernentea and its feeding structures.

Antisense inhibition of beta(1)-adrenergic receptor mRNA in a single dose produces a profound and prolonged reduction in high blood pressure in spontaneously hypertensive rats

BACKGROUND

beta-Blockers are the first line of therapy for hypertension. However, they are associated with side effects because of central nervous system (CNS) effects and beta(2)-adrenergic antagonism. To overcome these problems and provide a long-term beta(1)-blockade, antisense oligonucleotides against rat beta(1)-adrenergic receptor (beta(1)-AR) mRNA (beta(1)-AS-ODN) were designed and tested for the ability to inhibit cardiac beta(1)-ARs as well as lower blood pressure in spontaneously hypertensive rats (SHRs).

METHODS AND RESULTS

Radioligand binding assay showed that a single intravenous injection of beta(1)-AS-ODN delivered in cationic liposomes significantly decreased cardiac beta(1)-AR density by 30% to 50% for 18 days (P<0.01), with no effect on beta(2)-ARs. This was accompanied by marked attenuation of beta(1)-AR-mediated positive inotropic response in isolated perfused hearts in vitro (P<0.02) and in conscious SHRs monitored by telemetry in vivo (P<0.02). Furthermore, the blood pressure of SHRs was reduced for 20 days, with a 38 mm Hg maximum drop. Heart rate was not significantly decreased. Quantitative autoradiography was performed to assess beta(1)-AS-ODN effects on the CNS, which demonstrated no changes in beta(1)-ARs in brain, in contrast to a significant reduction in heart and kidney (P<0.05). For comparison with beta-blockers, the effects of atenolol on cardiovascular hemodynamics were examined, which lowered blood pressure for only 10 hours and elicited appreciable bradycardia in SHRs.

CONCLUSIONS

These results indicate that beta(1)-AS-ODN, a novel approach to specific beta(1)-blockade, has advantages over currently used beta-blockers in providing a profound and prolonged reduction in blood pressure without affecting heart rate, beta(2)-ARs, and the CNS. Diminished cardiac contractility resulting from less beta(1)-AR expression contributes to the antihypertensive effect.

Intravenous angiotensinogen antisense in AAV-based vector decreases hypertension

Angiotensinogen (AGT) has been linked to hypertension. Because there are no direct inhibitors of AGT, we have developed antisense (AS) inhibition of AGT mRNA delivered in an adeno-associated virus (AAV)-based plasmid vector. This plasmid, driven by the cytomegalovirus promoter, contains a green fluorescent protein reporter gene and AS cDNA for rat AGT. Transfection of the plasmid into rat hepatoma cells brought a strong expression of the transgenes and a significant reduction in the level of AGT. In the in vivo study, naked plasmid DNA was intravenously injected into adult spontaneously hypertensive rats at different doses (0.6, 1.5, and 3 mg/kg). Expression of AGT AS mRNA was present in liver and heart, and it lasted longer in the liver. All three doses produced a significant decrease in blood pressure (BP). BP decreased for 2, 4, and 6 days, respectively. The lowest dose decreased BP by 12 +/- 3.0 mmHg, whereas the higher doses decreased BP by up to 22.5 +/- 5.2 mmHg compared with the control rats injected with saline (P < 0.01). The injection of the plasmid with liposomes produced a more profound and longer reduction (8 days) in BP. Consistent changes in plasma AGT level were observed. Sense plasmid had no effect. No liver toxicity was observed after injection of AS plasmid with or without liposomes. Our results suggest that the systemic delivery of AS against AGT mRNA by AAV-based plasmid vector, especially with liposomes, may have potential for gene therapy of hypertension and that further studies with the plasmid packaged into a recombinant AAV vector for a longer-lasting AS effect are warranted.

Effectiveness of Glomus species in protecting white clover against nematode damage

Three species of arbuscular mycorrhizal (AM) fungi, Glomus aggregatum Schenck and Smith emend. Koske, Glomus intraradices Schenck and Smith, and Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe, were evaluated for their effectiveness to suppress the plant parasitic nematode Meloidogyne incognita (Kofoid and White) Chitwood in white clover (Trifolium repens L.) in a greenhouse study. Forty 1-day-old seedlings not colonized or colonized to the same extent by the fungi were transplanted into a growth medium uninoculated or inoculated with 10 000 M. incognita eggs. After 40 days of further growth, root mass, shoot mass, extent of galling, number of nematodes and nematode eggs in roots, and extent of mycorrhizal colonization of roots were determined. Growth of white clover was significantly stimulated by mycorrhizal colonization, and nematodes caused the greatest damage when plants were not colonized by the fungi. The degree to which mycorrhizal fungi reduced nematode damage varied with the species of mycorrhizal fungus; the extent of damage reduction ranged from 19 to 49.8%, based on loss of shoot mass. The effectiveness of the mycorrhizal fungal species in suppressing nematodes was not related to the degree to which they colonized roots or their effectiveness in enhancing host growth.Key words: AM colonization, galls, Glomus aggregatum, Glomus intraradices, Glomus mosseae, inoculum potential, Meloidogyne incognita, nematode eggs, phosphorus.

Upregulation of endothelial receptor for oxidized low-density lipoprotein (LOX-1) in cultured human coronary artery endothelial cells by angiotensin II type 1 receptor activation

Cross talk between oxidized LDL (ox-LDL) and angiotensin II (Ang II) may be relevant in atherosclerosis. In this study, we examined the presence of a specific endothelial receptor for ox-LDL (LOX-1) and Ang II receptors in human coronary artery endothelial cells (HCAECs). In addition, we studied the effect of Ang II on LOX-1 gene and protein expression. LOX-1 was consistently identified in HCAECs by reverse transcriptase-polymerase chain reaction (RT-PCR), cDNA sequence, Western blot, and 125I-labeled ox-LDL binding assay (Bmax, 29.7 ng/mg protein). The HCAECs also exhibited Ang II receptors (AT1>AT2), as determined by RT-PCR and 125I-labeled Ang II binding assay (Bmax, 2.21 and 1.19 fmol/mg protein, respectively). Incubation of HCAECs with Ang II markedly increased LOX-1 mRNA (RT-PCR) and protein (Western blot) expression. The increase in LOX-1 expression was dependent on Ang II concentration (10(-12) to 10(-6) mol/L). Ang II caused a concentration-dependent increase in 125I-labeled ox-LDL uptake by HCAECs and enhanced ox-LDL-mediated cell injury, as evident from an increase in LDH release and a decrease in cell viability. These effects of Ang II were completely blocked by pretreatment of HCAECs with losartan, a specific AT1 blocker, but not by PD123319, a specific AT2 blocker. These observations indicate the following: (1) HCAECs possess abundant LOX-1 as well as Ang II (AT1>AT2) receptors, (2) Ang II upregulates LOX-1 receptor and ox-LDL uptake, (3) the effects of Ang II are mediated by AT1 activation, and (4) Ang II enhances ox-LDL-mediated injury to HCAECs.

Ultrastructure of the Esophagus of Diplenteron sp. (Diplogasterida) to Test Hypotheses of Homology with Rhabditida and Tylenchida

The ultrastructure of the isthmus and basal bulb (postcorpus) of Diplenteron sp. (Diplogasterida) was revealed through transmission electron micrographs of serial sections. The postcorpus is glandular and muscular. There are 26 cells in the postcorpus, including 6 marginal (two sets of three), 6 muscle (two sets of three), 3 gland, and 11 nerve cells. Most of the cell bodies, including the nuclei, are in the basal bulb. Unlike Caenorhabditis elegans, Diplenteron sp. has three gland cells. The glands are embedded in a muscular framework in both taxa, but each gland cell is much bigger in Diplenteron sp. than in C. elegans. Each of the anterior set of three marginal cells is located at the apex of the esophageal lumen and overlaps slightly with one of the posterior sets of three marginal cells. All six marginal cells in Diplenteron sp. have homologs in C. elegans. The anterior set of radial muscle cells is V-shaped and is homologous to m5 muscle cells in C. elegans. The posterior set of muscle cells appears to be homologous to m6 muscle cells in C. elegans. Diplenteron sp. does not have muscle cells corresponding to the m7 cells associated with the "grinder" in C. elegans, which is absent in diplogasterids. The single saucer-shaped muscle cell, m8, covering the posterior wall of the basal bulb in C. elegans was not observed in Diplenteron sp. The structure of the esophageal-intestinal junction in Diplenteron sp. is similar to that of C. elegans in being composed of five epithelial cells. Neurons appear to be more abundant in Diplenteron sp. than in C. elegans. Ultrastructure of the esophagus in diplogasterids, rhabditids, cephalobids, and tylenchids will be useful in testing classical and recent competing hypotheses of secernentean phylogeny.

Critical role of AT1 receptor expression after ischemia/reperfusion in isolated rat hearts: beneficial effect of antisense oligodeoxynucleotides directed at AT1 receptor mRNA

To examine the relevance of angiotensin II type 1 receptor (AT1R) expression in the determination of myocardial function after ischemia/reperfusion, Sprague-Dawley rats were treated intravenously with antisense oligodeoxynucleotides (AS-ODNs) directed at AT1R mRNA (100 microg/rat, n=9) or scrambled antisense oligodeoxynucleotides (Scr-ODNs, 100 microg/rat, n=6). Both AS-ODNs and Scr-ODNs were given along with 300 microg/rat of liposome DOTAP/DOPE, a positive electron carrier (wt:wt= 1:1). The hearts from AS-ODN- or Scr-ODN-treated rats were excised 24 hours later, perfused in vitro, and subjected to 25 minutes of global ischemia followed by 30 minutes of reperfusion. Parallel groups of rats were given the specific AT1R antagonist losartan (10 mg/kg IV, n=6) or saline (n=7) 4 to 6 hours before excising the hearts. Ischemia/reperfusion resulted in a significant increase in myocardial AT1R expression (autoradiography and binding assay) and myocardial dysfunction, indicated by increases in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in developed left ventricular pressure (all P<0.01 versus baseline) in the saline-treated group. AT1R protein and mRNA levels also increased in ischemic/ reperfused myocardial tissues. Administration of AS-ODNs or losartan, but not Scr-ODNs, preserved myocardial function and blocked the increased AT1R binding after ischemia/reperfusion (both P<0.01). Myocardial AT1R mRNA levels were not affected by either AS-ODNs or losartan, and the AT1R protein levels were significantly reduced by AS-ODN, but not losartan, treatment. Plasma angiotensin II levels increased after administration of losartan but not after administration of AS-ODNs. These observations imply a critical role of AT1R upregulation in determining myocardial function immediately after ischemia/reperfusion. AS-ODNs to AT1R mRNA may be more beneficial than losartan, because losartan does not affect the plasma angiotensin II level. The sustained increase in AT1R mRNA, but diminished protein expression, in rat hearts treated with AS-ODNs suggests that AS-ODNs block AT1R at the translational level.

Artemisinin blocks activating and slowly activating K+ current in guinea pig ventricular myocytes

AIM

To study the effect of artemisinin (Art) on outward rectifier potassium current in ventricular myocytes.

METHODS

In isolated guinea pig ventricular myocytes, the effects of Art on the two components of delayed outward rectifier K+ current (IK), the rapidly activating inward K+ current (IKr), and the slowly rectifying outward K+ current (IKs) were observed by the whole cell patch-clamp technique.

RESULTS

Art decreased IK in a concentration-dependent manner. The IKstep and IKtail were reduced from 387 +/- 46 pA to 240 +/- 48 pA and from 299 +/- 30 pA to 130 +/- 38 pA, respectively at holding potential of +40 mV by Art 50 mumol.L-1. The envelope of tail analysis suggested that both IKr and IKs were inhibited.

CONCLUSION

Art blocked the two components of delayed outward rectifier K+ current (IKr and IKs) in guinea pig ventricular cells.

Comparative study on 4 EIA kits for screening antibody to hepatitis C virus in pooled sera

Four enzyme immunoassay (EIA) test kits, 1 Canadian product and 3 Chinese products, were used in the comparative study. Each pool consisted of 5 sera, and the 5 single sera were tested as controls. The tests were carried out according to the instructions, keeping the same dilution of each serum in single and pool samples. It was found that with the Canadian kit, the positive and negative results of pooled sera had no difference from that of the controls (P > 0.10). In the case of Chinese Yali and Kehua kits, the positive results of pooled sera showed no difference from the controls (P > 0.10), but the optical density (OD) of negative pools were increased (P < 0.01), though quite distant from the cut-off values. In the case of Changzheng kit, the OD of positive pools were significantly lower than those of the controls (P < 0.05), and weak positive samples missed the detection. However this problem could be overcome by blocking the microwells beforehand. Our experiment demonstrate that not all EIA test kits are suitable for screening pools for antibody to hepatitis C virus, and that it is important to assess the sensitivity of the EIA kit to be used for this purpose.

A prospective study of a serum-pooling strategy in screening blood donors for antibody to hepatitis C virus

BACKGROUND

To examine the feasibility and to perform a cost-benefit analysis of a pooling protocol of enzyme immunoassay (EIA) screening for antibody to hepatitis C virus (anti-HCV) under real conditions, a prospective study was carried out using sera from 1875 local blood donors.

STUDY DESIGN AND METHODS

In the absence of knowledge of the anti-HCV reactions, the donor's sera were pooled into groups of five consecutive samples for testing by EIA. The dilution and final volume of the serum pool were adjusted to equal those recommended for single-serum EIA by the manufacturer of the test kit. The results obtained were compared with those of single-serum EIA to assess the feasibility of the pooling protocol. By applying probability theory, the percentage of reduction in the number of tests performed (L value) when the serum-pooling strategy was used was calculated for several anti-HCV seroprevalences and for varied sizes of pool. The calculations were performed on a computer using a program compiled by the authors.

RESULTS

The results showed that seroprevalence was 2.24 percent (95% CI, 1.57-2.91%); the rate of false negativity was 0 (95% CI, 0-8.4%), the sensitivity of the pooling protocol was 100 percent (95% CI, 91.6-100.0%), the rate of false positivity was 0.8 percent (95% CI, 0-1.8%), and the specificity of the pooling protocol was 99.2 percent (95% CI, 98.2-100.0%). Cost-benefit analysis showed that the pooling protocol could save 69.3 percent of the cost. A table of L values can be used conveniently by serologists to determine the optimum pool size if estimates of seroprevalence are available.

CONCLUSION

The pool EIA did not perform worse than individual EIAs, and the pooling strategy was markedly less expansive. The pooling protocol was recommended for screening of anti-HCV-positive subjects from large populations with low seroprevalence.

Thymocyte apoptosis in response to low-dose radiation

Thymocyte apoptosis was assessed by counting apoptotic bodies with flow cytometry (FCM) and measuring DNA fragmentation with fluorescence spectrophotometry (FSP). J-shaped dose-response curves were obtained after both whole-body irradiation (WBI) of mice and in vitro irradiation of EL4 cells with doses ranging from 0.025 to 4 Gy X-rays. There was a significant reduction of apoptosis rate to below control level with doses within 0.2 Gy, and a dose-dependent increase in apoptosis with doses above 0.5 Gy. When thymocytes were cultured 24 h after WBI with 75 mGy X-rays in complete RPMI 1640 medium, a reduction in apoptosis was observed in the course of incubation for 72 h, and the presence of Con A in the medium accentuated this reduction in a dose- and time-dependent manner. The implications of these observations and the possible molecular mechanisms for future studies are proposed.

Evidence that disruption of connexon particle arrangements in gap junction plaques is associated with inhibition of gap junctional communication by a glycyrrhetinic acid derivative

Glycyrrhetinic acid exhibits many pharmacological activities, including the ability to block gap junctional communication. However, the mechanism of glycyrrhetinic action is not clear. Others have shown that glycyrrhetinic acid apparently binds to a single proteinatious binding site in the plasma membrane. We present evidence that while exposure to glycyrrhetinic acid derivatives may not affect protein synthesis or location, it does seem to alter connexon particle packing in gap junction plaques.

Effect of low dose radiation on intracellular calcium and protein kinase C in lymphocytes

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming mice with 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+]i mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBI with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed.

Signal transduction in lymphocytes after low dose radiation

Mice were given whole-body irradiation (WBI) with 75 mGy X-rays which had previously been found to stimulate immunologic functions. This low dose radiation (LDR) potentiated [Ca2+]i mobilization in thymic and splenic lymphocytes in response to Con A and anti-CD3 McAb and activated protein kinase C in T and B lymphocytes of the spleen. The expression of TCR/CD3 molecules on the thymocytes was enhanced after LDR indicating an expedited maturation and differentiation process in the thymus. The changes in TCR/CD3 expression and [Ca2+]i mobilization in response to McAb-CD3 after LDR was found to be highly correlated. Meanwhile the transcription of c-fos and c-jun genes was up-regulated beginning 3 hours after LDR. The expression of IL2R in active thymocytes was potentiated 24 hours after LDR which coincided with the previous finding of increased secretion of IL2 by splenocytes after WBI with 75 mGy X-rays. It is first reported in the present paper that LDR could stimulate immunologic functions through facilitation of the signal transduction process in the lymphocytes.

Geographic pathology of gastric dysplasia in China

Six hundred seventeen cases of gastric dysplasia were studied morphologically and were grouped histogenetically into adenomatous, cryptal, regenerative, and globoid dysplasias. The characteristics and their relationships with various histological types of gastric carcinoma were analysed as well. Twenty-four cases of gastric dysplasia showed malignant change, which was most commonly seen in regenerative dysplasia in five high-incidence areas of gastric dysplasia in China. The causative factors of gastric dysplasia, especially regenerative dysplasia, were analysed in terms of foodstuffs and eating habits of the local inhabitants.

An epidemic of encephalitis and meningoencephalitis in children caused by echovirus type 30 in Shanghai

An outbreak of viral central nervous system infection occurred from May to September, 1991 in Shanghai, China. Totally 376 cases were admitted into our hospital, 54% with encephalitis and 46% with meningoencephalitis. Echovirus type 30 was isolated from CSF and stools of the patients. Only 3 of the patients were under 1 year of age. CSF examination revealed the cell count from 0-1600 x 10(6)/L. Interestingly, 9 had CSF PMNs over 90% and 13 had low sugar levels. EKG was randomly done in 20 patients and 15 demonstrated myocarditis. The outcome was uneventful in all except 1 who had psychological problem at the time of discharge.

[A study on the effect of dynorphin A- (1-13) ICV injection on water, sodium and potassium excretion of rats]

The effect of Kappa-agonist dynorphin A-(1-13) on the urine flow was studied in ethanol-anesthetized rats. Intracerebroventricular injection of dynorphin A- (1-13) (5 micrograms, 10 micrograms) induced a potent diuretic response with insignificant action on mean arterial pressure and heart rate. The diuretic response began to show at about 20 min after injection and lasted 120 min. This diuretic effect could be almost completely blocked by pretreatment with naloxone (20 micrograms) or atropine (10 micrograms).

Geographic pathology on the precursors of stomach cancer

The classification of dysplasias of the gastric mucosa used in our institute includes adenomatous dysplasia, regenerative dysplasia, and cryptal dysplasia. We compared the incidence of gastric dysplasia in three regions of China which have quite different geographical environments: the loess plateau of Wuwei area in the Gansu Province, the island of the Yangtze River in the Jiangsu Province of southern China, and the coastal area of the Liaoning Province in northern China. The mortality rate of stomach cancer in these areas is more than 50 per 100,000. We found a total of 323 cases of gastric dysplasia in these three areas. Regenerative dysplasia is the most common precancerous lesion of the stomach and was found in 40% of the cases from the three high-risk areas of gastric cancer. The background lesions consist of gastric erosions, severe gastritis, gastric ulcers, and intestinal metaplasia, which indicate that some factors causing damage to gastric mucosa are very important in the histogenesis of stomach cancer. The gastric dysplasia sites involved are different in the three geographical regions studied. On the island of the Yangtze River, cardiac dysplasia and intestinal metaplasia are common (75%), and cancer of the cardia is also common. In the other two geographical areas, antral dysplasia predominates (85 to 91%). The finding of different sites of gastric dysplasia in different geographical environments may be very important in our search for etiological factors of gastric cancer and may allow for beneficial intervention in the prevention of this disease.

Geographic survey of cancer in China

Cancer incidence in China shows characteristics related to geographic distribution, ecological factors, dietary and nondietary habits, lifestyles and living conditions, and occupational factors. The random interaction of these factors resulted in a markedly uneven distribution of each of the major types of cancer throughout China. This article reviews the main types of cancer found in China in relation to their relevant epidemiological factors.

Effects of berbamine on contraction and Ca2+ influx of pig basilar artery

Effects of berbamine (Ber) on KCl- and 5-HT-induced contraction of basilar artery (BA) of pigs were studied in vitro. Ber relaxed markedly KCl-induced contraction of BA (IC50 = 4.63 mumol.L-1) and its effect was antagonized by increasing the concentration of extracellular Ca2+; Ber inhibited 5-HT-induced contraction of BA, showing significant inhibition of sustained tonic contraction (STC) (IC50 = 0.64 mumol.L-1) whereas the initial fast phasic contraction (FPC) was relatively unaffected (IC50 = 19.8 mumol.L-1); the 5-HT-induced contraction of BA was dependent on the concentration of extracellular Ca2+, especially STC. The results of Ca2+ withdrawal and replacement indicated that STC was due to 5-HT-stimulated Ca2+ influx, while 5-HT-induced release of intracellular Ca2+ resulted in FPC. Ber 0.8 mumol.L-1 produced markedly inhibitory effect on Ca2+ influx induced by 5-HT (P < 0.01). The effects of Ber were similar to those of nimodipine (Nim). The present results suggested that Ber has antagonistic effect on the potential sensitive channels (PSC) and the receptor operated channels (ROC).

Radioimmunolocalization of human gastric carcinoma xenografts SY 86 B and SY 86 D with 131I-labeled monoclonal antibody

The suitability of individual MAb for application in vivo should be carefully confirmed. The monoclonal antibody GL-013, with specific binding reactivity in vitro to human tumors of the gastrointestinal tract, was radioiodinated and injected intraperitoneally into nude mice bearing human gastric carcinoma xenografts SY 86 B (moderately differentiated glandular adenocarcinoma) and SY 86 D (signet ring cell carcinoma). Whole body scintigraphy indicated tumor localization with 131I-labeled MAb GL-013, but not with 131I-labeled normal mice immunoglobulin. The best tumor contrast was obtained between days 3 and 7 after injection. As confirmation of the imaging results, 131I-GL-013 preferentially localized in tumor tissue compared with normal tissue and 131I-GL-013 gave a higher tumor uptake ratio than the control 131I-NMIgG (at day 9 after injection), as determined by tissue counting of radioactivity. These results demonstrate that MAb GL-013 localizes in xenografts SY 86 B and SY 86 D and the possible clinical application of MAb GL-013 to radioimmunolocalization.

Clinical studies on bladder tumor-associated antigen in serum of patients with bladder cancer by using monoclonal antibody and sandwich ELISA

Investigations on tumor-associated antigen in the serum of patients with bladder cancer by using monoclonal antibody Hb 7A and sandwich ELISA were carried out on 36 patients with bladder cancer (BCa group), 18 patients with other tissue tumor (OTT group) and 22 normal subjects (control group). The average OD value of Hb 7A antigen of BCa group, OTT group and control group was 0.315 +/- 0.033, 0.124 +/- 0.026 and 0.12 +/- 0.021 respectively. The OD value of Hb 7A antigen in BCa group was significantly higher than that of control group and of OTT group (P less than 0.01), but there was no obvious difference between the control group and OTT group (P greater than 0.05). The positive detection rate in BCa group was 86% (31/36), while detection in all 22 normal subjects and the 18 patients of OTT group yielded negative results. The results indicated that the method of using McAb Hb 7A and sandwich ELISA, characterized by high specificity and sensitivity, is of value for clinical diagnosis and follow-up of patients with bladder cancer and general survey of persons at high risk of bladder cancer.

[A histochemical study of diethylnitrosamine-induced altered liver cells in rats]

The histochemical changes of gamma-glutamyltransferase (gamma-GT), adenosine triphosphatase (ATPase), glucose-6-phosphatase (G-6-Pase) and ornithine carbamyltransferase (OCT) were studied in diethylnitrosamine (DEN) -induced and enzyme-altered liver cell lesions (Solt-Farber model) in rats. The number of altered liver cell foci tended to decrease after ceasation of 2-acetylaminofluorene (2-AAF); nevertheless, the number and size of the nodules increased rapidly within 20 weeks. The histochemical changes of most of the altered liver cell foci were focused on one or two kinds of enzyme activity (mostly gamma-GT and ATPase); while most of the nodules presented 3 or 4 kinds of histochemical changes, including OCT and G-6-Pase. It is concluded that some of those altered nodules of multi-enzyme changes might develop continuously to become tumors.

Immunopathological study on human cartilage allografts

The fate of human cartilage allografts and the mechanism of its kinetical development were studied histopathologically and immunohistologically. After transplantation, the grafts underwent necrosis, calcification and were partially invaded by osteoplastic tissue of the host and eventually replaced by bone tissue. Thus, the contour of the transplanted cartilage was kept partially by the living cartilage and the newly-formed osseous tissue. The grafts were surrounded initially by granular tissue and then by scar tissue, in which numerous T cells and a few macrophage infiltrates were noted. In T cells, T4+ lymphocytes predominated but T8+ cells accounted for a small number. B cells were not found within the infiltrates. Most of the infiltrating cells expressed 12 antigens, indicating that the majority of T cells were activated. It was concluded that T lymphocytes mediated cellular immunity played an important role. The chondrocytes of the cartilage did not express HLA I and II antigens before transplantation, but one month later, the living chondrocytes became HLA I and II antigens positive, and the antigen expression became stronger with the elapse of time; this might be induced by lymphokins, especially by interferon produced by the infiltrating lymphocytes. Such an expression of MHC antigens on chondrocytes might contribute to the further enhancement of immunorejection.

Invasion and metastasis of SY86B human gastric carcinoma cells in nude mice

A moderately differentiated tubular adenocarcinoma of human stomach, named SY86B, was successfully transplanted subcutaneously to nude mice of different genetic backgrounds (BALB/CA/PBI-nu, C57BL/6J.615/PBI-nu and ICR.BALB/CA/PBI-nu). The tumor has been passaged for 13 generations and the transplantability was 100%. The SY86B cells retained the capacity of invasive and metastatic growth in the nude mice and showed a high rate of metastasis to the regional lymph nodes and to such distant organs as the lungs, liver and pancreas. The overall rate of metastasis was 77.7%. The species of the nude mice, their age and sex apparently did not significantly affect the occurrence of metastasis. Tumor-bearing time and the aggressive character of the tumor cells themselves appeared important for the genesis of metastasis. This experimental model can provide a new approach to basic and clinical studies of cancer metastasis.

Histochemistry and electron microscopy in the diagnosis of small mucous cells in carcinoma of the stomach

One hundred and two cases of poorly differentiated adenocarcinoma were obtained from 71 surgical and 31 biopsy specimens of the stomach. These tumours produced both intracellular and extracellular mucins, which were demonstrated to be neutral mucins, N-acetyl sialomucins, sulphomucins and O-acetyl sialomucins. The majority of tumours (85.3%) secreted two or more kinds of mucins simultaneously, but only a small proportion (14.7%) produced a single kind of mucin. Ultrastructurally, three types of mucin granules were identified; these differed in shape and density. Tumour cells containing intracellular mucins or mucin granules were designated as mucous cancer cells and further subdivided into small, large and goblet mucous cells; tumour cells having neither mucins nor glandular differentiation were designated as undifferentiated cancer cells. These histochemical distinctions, supported by the electron microscopical observations, may be useful to demonstrate early malignant foci in gastric biopsies.