Attenuating effect of antithrombin III on the fibrinolytic activation and microvascular derangement in rat gastric mucosa

The roles for the fibrinolytic activation and disorder of coagulation in formation of gastric ulcer induced by microvascular derangement were investigated. The rat stomach was exposed and repeated electrical stimuli (RES) were applied on the small arterial wall close to the lesser curvature to induce mucosal microcirculatory disturbances. The level of tissue-type plasminogen activator (t-PA), a key enzyme for fibrinolytic activity, in the regional blood of the stomach was significantly elevated immediately after RES. At 5 min after RES, the leakage of FITC-labeled albumin and thrombus formation in the mucosal microvasculature were visually demonstrated by using an intravital microscopic system. At 30 min, hemorrhagic erosions and linear ulcers were observed in the gastric mucosa. Pretreatment with human antithrombin-III (AT-III) in the range of 0.1-10 U/kg dose-dependently attenuated both the fibrinolytic activation and microvascular alteration promoted by RES. Human AT-III also prevented RES-induced gastric mucosal injury. Thrombin inhibitory activity in the gastric vein decreased (69.0 +/- 2.1%) just after RES, and further reduced at 30 min (47.7 +/- 5.3%). The present study suggests a hypothesis that human AT-III has a preventive effect on the gastric mucosal hemorrhagic changes via attenuating the fibrinolytic activation and subsequent microcirculatory disturbances.

The effects of immobilization of long segments of the spine on the adjacent and distal facet force and lumbosacral motion

Long levels of spinal instrumentation and fusion are common in surgery for spinal deformity. The effect on the remaining mobile segments is not well understood. The changes in lumbar facet loading and lumbosacral motion were evaluated as the number of immobilized levels increased. Four fresh canine cadaveric spines from T6 to sacrum were used. Lumbosacral motion was measured with an instrumented spatial linkage device, and facet loads were measured at L1, L4, and L7 using a strain gauge technique. Lumbosacral motion and facet loading were significantly increased (P < 0.05) after immobilization of proximal segments, and the amount of the increase was dependent on the number of immobilized segments (P < 0.05). This indicates that immobilization of long segments of the spine influences the remaining mobile segments by increasing the load and motion not only at the immediately adjacent segment but also at the distal segments.

Schwarzschild microscope for carbon Kα radiation

A Schwarzschild objective (magnification, ×32; numerical aperture, 0.2), which has a 0.1-µm resolution within 30 µm of the object height, was designed and fabricated. We have developed new normalincidence multilayer mirrors for carbon Kα radiation (wavelength, 44.8 Å), NiCr (80-20 wt. %)/C multilayers (thickness period, 22.5 Å; number of layers, 50), which are deposited by ion-beam sputtering with the thickness distribution corrected by deposition masks. Magnified images were taken on photographic film with the Schwarzschild objective by using an electron impact carbon Kα radiation source, and a resolution of < 0.5 µm was confirmed.

Inhibition of coaggregation between Porphyromonas gingivalis and Streptococcus oralis by fibrinogen fragments

The localization of regions of fibrinogen that inhibit coaggregation between Porphyromonas gingivalis and Streptococcus oralis was investigated. The coaggregation was inhibited by A alpha and gamma chains, but not by B beta chain. The inhibitory activity of fragment D was more potent than that of fragment E. Some cyanogen bromide-treated fragments isolated from A alpha and gamma chains including the NH2-terminal 148-207 amino acid residues of A alpha chain (A alpha 148-207) and gamma 1-78 showed inhibitory activities. A alpha 148-207 was further digested with lysyl endopeptidase. A alpha 158-176 and A alpha 192-206 which contained four and two arginine residues, respectively, retained the inhibitory activities. When the arginine residues of these two peptides were modified by phenylglyoxal, the inhibitory activities were much reduced. These findings suggest that the arginine residues of some specific regions of fibrinogen may play an important role in the inhibition of the coaggregation.

[Efficacy of the treatment of gastric cancer as neo-adjuvant chemotherapy of 48 hour continuous intravenous infusion of 5-fluorouracil (5-FU) with leucovorin (LV)]

A 51-year-old female with inoperable gastric cancer and with infiltration of pancreatic tail diagnosed by abdominal CT was treated with leucovorin (LV) and 5-fluorouracil (5-FU). The regimen was: LV 30 mg/body/24 hr prior to 5-FU 1,000 mg/m2/day for 48 hrs. This treatment was repeated 6 times. After treatment, the size of tumor decreased so that the patient was able to be operated (Total gastrectomy with partial distal pancreatico-splenectomy). During the treatment, patient showed no side effect except for slight nausea. This neo-adjuvant chemotherapy might be a recommendable treatment of advanced gastric cancer.

Mechanical stimulation by toothbrushing increases oxygen sufficiency in human gingivae

We studied the immediate effect of mechanical stimulation with a toothbrush on oxygen sufficiency in human gingivae. Teeth were brushed with a modified Bass technique at various forces (100, 200, and 300 g) for various times (5, 10, and 30 s). Hemoglobin (Hb) oxygen saturation was measured before and intermittently for 60 min after brushing, by non-invasive tissue reflectance spectrophotometry. Hb oxygen saturation increased within a few min after brushing and then slowly returned to the initial level. Toothbrushing at 200 g for 10 s caused the longest-lived increase in Hb oxygen saturation; saturation remained about 6% above the baseline level for more than 25 min. Before brushing, Hb oxygen saturation was significantly lower in inflamed gingivae than in healthy gingivae (p < 0.05). After brushing of inflamed gingivae, the Hb oxygen saturation almost reached the level measured in healthy gingivae before brushing. These findings suggest that stimulation with a toothbrush increases oxygen sufficiency in both healthy and inflamed gingivae.

Protein-losing enteropathy caused by mesenteric vascular involvement of neurofibromatosis

A 44-year-old man with neurofibromatosis suffered from severe diarrhea and progressive hypoproteinemia. Enteric protein loss was confirmed by an alpha 1-antitrypsin clearance test. An x-ray study showed irregular mucosa in the distal segment of the ileum. Protein loss has subsided after ileocecal resection. Laparotomy and radiological examinations failed to demonstrate neurofibroma or other tumors in the abdomen. The resected ileum revealed marked edema of the wall and a pseudomembranous enteritis-like appearance in the luminal surface. Microscopically, lymphatic vessels in the intestinal wall were dilated. Marked thickening of the intima with spindle cell proliferation was observed in the mesenteric arteries and veins. This finding is consistent with vascular changes in neurofibromatosis. These vascular changes in the mesentery due to neurofibromatosis may cause protein-losing enteropathy by altering the hemodynamic state and microvascular permeability in the intestine.

Regional differences in microvascular response in rat intestine during acute elevation of portal pressure

The effect of acute elevation of portal pressure on the blood flow of rat intestinal microvessels was studied using a laser Doppler velocimeter and in vivo microscopy. The total intestinal blood flow decreased when portal pressure increased more than +15 cmH2O above the basal value. Blood flow in villus capillaries did not change at portal pressures of +5 to +15 cmH2O, but did decrease at +20 cmH2O. Blood flow in muscle capillaries decreased at all steps of portal hypertension. Red blood cell velocity was decreased by portal hypertension in large venules, but not in small venules of the submucosa. Large venules, but not small venules, dilated in acute portal hypertension. Large arterioles in the submucosa constricted, while small arterioles dilated at portal pressures of +10 to +15 cmH2O. In conclusion, the intestinal microvascular flow response differs according to the degree of portal hypertension and the location on the microvascular tree. Blood flow in villus capillaries and in small submucosal venules is maintained at a small degree of portal hypertension.

Further histological observations on popliteal lymph nodes after interruption of the afferent lymphatic vessels

Lymphatic vessels afferent to the popliteal nodes in young adult rats and guinea pigs were interrupted at the lowest edge of the popliteal fossa, and regressive changes in the nodes occurring 4 to 16 or 18 weeks after surgery were re-examined histologically. In the rat, some popliteal nodes were drained by lymphatic channel(s) from the tail. After surgery, the popliteal nodes without lymphatic channel(s) from the tail underwent regression of all their constituent deep cortical units and also the peripheral cortex comprising lymph follicles, until at 18 weeks, the lymphoid organization of the node reached a minimal level. On the other hand, in popliteal nodes having a lymphatic channel from the tail, some deep cortical units and the overlying peripheral cortex underwent hypotrophy, leaving the remaining units and their overlying peripheral cortex little affected. In the guinea pig, the treated nodes underwent progressive atrophy and ultimately became rudimentary, or even vanished, after 16 weeks. Treated rudimentary nodes were composed largely of stromal cells only, and these were replaced to a various extent by fat. The present results are discussed in relation to complete and incomplete inhibition of the afferent lymph flowing into the surgically treated nodes.

Nitric oxide mediates vasoactive effects of endothelin-3 on rat mesenteric microvascular beds in vivo

In order to clarify whether the vasoactive effects of endothelin-3 (ET-3) on microvessels are associated with the endothelium-derived relaxing factor (EDRF) in vivo, the authors examined the effects of L-NG-monomethyl arginine (L-NMMA), an analog of L-arginine, on low-dose ET-3 induced hemodynamic changes in the mesenteric microcirculation of male Wistar rats. The intravital observation revealed that ET-3 100 pM induced a remarkable and periodic vasoconstriction in arterioles, and the constriction was sustained for approximately fifteen minutes. No remarkable change was observed in the microvessels after the superfusion of 1 pM ET-3. Superfusion of 1 pM ET-3 with 100 microM L-NMMA elicited the vasoconstriction in arterioles, and the arteriolar diameter recovered to the control level within ten minutes in spite of continuing the superfusion. The vasoconstriction induced by low-dose ET-3 with L-NMMA was suppressed by the additional superfusion of 200 microM L-arginine. The present study suggests that the recovery of arteriolar diameter after the ET-3-induced constriction may be mediated by nitric oxide at least in the early phase.

[Effects of protease inhibitors and protein synthesis inhibitors on cartilage tissue-dependent bone resorption]

We studied bone resorption of fetal rat femora in association with cartilage tissue. Some protease inhibitors, e.g., E-64, pepstatin A, phosphoramidon, amastatin, bestatin, foroxymithine, did not influence the bone resorption, but some serine protease inhibitors such as PMSF, TLCK, TPCK and elastatinal inhibited the bone resorption at 10(-5) M, 10(-4) M, 10(-4) M, 10(-4) M, respectively. A conditioned medium, obtained from cartilage tissue-cultured medium in the presence of 10(-4) M TPCK, which was then excluded from the medium by dialysis after the culture, stimulated the bone resorption. Cycloheximide (0.1 to 10 micrograms/ml) and puromycin (0.3 to 30 micrograms/ml) inhibited the cartilage tissue-dependent bone resorption. A A transient treatment of the femora with cycloheximide (3 micrograms/ml) for a day inhibited the bone resorption, but after the treatment, in the absence of cycloheximide, the femora gradually recovered the bone-resorbing activity. The conditioned medium, obtained from cartilage tissue-cultured medium in the presence of cycloheximide (3 micrograms/ml), which was then excluded from the medium by dialysis after the culture, failed to influence the bone resorption. These findings collectively suggest that cartilage tissue produces a bone resorption-stimulating factor(s) which is a serine protease or contains the protein as an inactive, latent form and then a certain serine protease converts it to an active form.

[Influence of epiphyseal cartilages on bone resorption of fetal rat femora]

We developed a facile method for studying bone resorption using fetal rat femur by labelling the bone with 45Ca in vitro. We found that cartilages stimulated the bone resorption of a shaft which was obtained by cutting off both distal and proximal cartilages from the femur. When the shaft was co-cultured with the cartilages isolated by a 0.4-microns microporous membrane in the same Transwell, the bone resorption of the shaft was increased. This finding suggests that the stimulation of bone resorption by the cartilages is not a result of recruitment of osteoclasts or the precursor cells from the cartilages. Indomethacin (10(-6) M) failed to influence the bone resorbing activity of the cartilages. The bone resorbing activity in the supernatant obtained from the cartilage-culture was decreased by heating. The bone resorbing activity of the supernatant did not remain in the lipid-extract or the pronase-digested supernatant, but was present in a fraction whose molecular weight was greater than 50,000. These results collectively suggest that the cartilages produce a bone resorption-stimulating factor(s) which is water-soluble, is a non-prostanoid material, contains protein and has a molecular weight greater than 50,000.

[Anesthetic management for cesarean section and clipping of aneurysm in a pregnant woman with ruptured cerebral aneurysm]

We report an anesthetic management for Cesarean section and clipping of aneurysm in a pregnant woman with a subarachnoidal hemorrhage secondary to a ruptured cerebral aneurysm. Anesthesia was induced with thiopental, vecuronium and sevoflurane, and maintained with sevoflurane (0.5-1%) before the delivery. Apgar score at 1 min was 1, but after 30 min her activity became almost normal. After the delivery, anesthesia was maintained with fentanyl for clipping surgery, because sevoflurane may inhibit uterine contraction and increase bleeding from the uterus after the delivery. We also infused prostaglandin E1 continuously at a rate of 50-70 ng.kg-1.min-1 to control arterial blood pressure and to maintain good contraction of the uterus during clipping surgery. We conclude that prostaglandin E1 is useful as a vasodilator after delivery because prostaglandin E1 contracts the uterus.

Antithrombotic effect of an anti-glycoprotein IIB/IIIA antibody in primate lethal thrombosis

We investigated the antithrombotic effect of anti-glycoprotein (GP) IIb/IIIa antibody in a primate model of lethal thrombosis. Eight monkeys were injected intravenously with an anti-CD9 antibody (MALL13). They died within 5 min and displayed severe thrombocytopenia. Histological examination showed multiple platelet thrombi in the pulmonary microvasculature, but no thrombi in the liver, kidneys, or spleen. In contrast, monkeys pretreated with an anti-GPIIb/IIIa antibody (NNKY1-32) at 30 min before MALL13 administration did not die, and the thrombocytopenia in these animals did not develop as rapidly or become as severe. These results suggest that the antiCD9 antibody caused lethal pulmonary thrombosis in vivo, and that pretreatment with the anti-GPIIb/IIIa antibody was able to prevent this thrombosis.

Oxyradical generation from leukocytes during endotoxin-induced microcirculatory disturbance in rat mesentery--attenuating effect of cetraxate

By using the intravital microscope equipped with digital imaging processor, we investigated the granulocyte-mediated oxidative burst during the endotoxin-induced microvascular derangement in rat mesentery. The leukocyte behavior after the injection of acridine orange was detected by using a silicon-intensified target camera, the erythrocyte velocity was measured by using a high-speed video camera system, and the luminol-dependent photoemission was visualized by an ultrasensitive photon-counting camera in lipopolysaccharide (LPS)-treated microvascular beds. At 60 min after the LPS administration, a significant leakage of FITC-labeled albumin was observed along mesenteric venules under a fluorescence microscopy. The number of sticking leukocytes increased in association with the decrease in erythrocyte velocity after starting the LPS infusion. The luminol-dependent chemiluminescence in microvascular beds gradually increased over that recorded prior to LPS exposure and was fourfold higher 60 min after the start of LPS infusion. The distribution of the photoemission clearly corresponded to the venular endothelium, to which leukocytes adhered. In blood samples taken from the mesenteric vein at 60 min after the LPS administration, a decrease in the number of granulocytes and increases of total and individual chemiluminescence activities were observed. These results suggest that LPS induces oxidative burst from granulocytes on the venular endothelium. Cetraxate, an inhibitor of proteases including plasmin, significantly inhibited the leukocyte activation and prevented alterations in microvascular hemodynamics induced by LPS in vivo, whereas it had no effect on the LPS-induced oxyradical generation from adherent leukocytes in vitro. The present study demonstrates that proteases such as plasmin may play an important role in the pathogenesis of endotoxin-induced microvascular disturbances.

Fluorographic study on the oxidative stress in the process of gastric mucosal injury: attenuating effect of vitamin E

In vivo oxidative change was visualized in the gastric mucosa of rats and the alteration was analysed by using a fluorescence microscope equipped with a digital imaging processor during the development of mucosal damage. Dichlorofluorescein (DCF)-associated fluorescence increased after the repeated electrical stimulation on the gastric artery (irritation), suggesting the occurrence of lipid peroxidation. The increase was enhanced in the mid-zone of two adjacent collecting venules. Allopurinol attenuated the oxidative stress in mucosa, showing the involvement of xanthine oxidase. Luminol-dependent chemiluminescence value in the blood taken from gastric vein was elevated by the irritation, suggesting that leucocyte-generated oxygen radicals also participate in this oxidative process. alpha-Tocopherol attenuated both the DCF activation and the increase in chemiluminescence value and prevented gastric mucosal injury. The present results suggest that alpha-tocopherol may be useful for the prevention of oxidative alteration in gastric mucosa.

The superoxide generation of neutrophils in normal and preeclamptic pregnancies

OBJECTIVE

To determine whether preeclampsia enhances superoxide generation of neutrophils.

METHODS

Samples were obtained from 12 normal nonpregnant, 15 normal pregnant, and 11 preeclamptic women. The superoxide production of neutrophils was measured by the superoxide dismutase-inhibitable reduction of ferricytochrome C at 550-540 nm using a dual-wavelength spectrophotometer.

RESULTS

N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced superoxide production of neutrophils was significantly higher in preeclamptics than in normal nonpregnant and pregnant subjects, whereas phorbol 12-myristate 13-acetate-induced superoxide production did not differ among them. When neutrophils prepared from normal nonpregnant women were preincubated with sera from the study groups, sera from preeclamptics enhanced the FMLP-induced superoxide production to about twice that of the other subjects. The serum-enhancing factor appeared to be a heat-labile protein, different from other known activators.

CONCLUSION

Preeclampsia is characterized by the presence of a neutrophil activator that enhances superoxide production. This enhanced production may contribute to the pathophysiologic changes observed in preeclampsia.

Mathematical modeling of fetal organ growth using the Rossavik growth model: II. Adrenal gland

Growth of the fetal adrenal gland has been monitored by measurements of the circumference (AGC) and area (AGA) of the adrenal gland from 16 to 40 weeks menstrual age. Growth curves for these parameters have been determined using a Rossavik growth curve models [P = c(t)k + s(t)]. R2 values of 86.2 and 91.1% were obtained for AGC and AGA, respectively. Variability analysis indicated a progressive increase in variability with menstrual age for these two parameters. Variability data were used with the growth curve models to determine standard curves for AGC and AGA. These standard curves provide a superior means for evaluating the adrenal growth in the fetus and the fetal status in utero in high-risk pregnancies.

The decreased immune responses in macular mouse, a model of Menkes' kinky hair disease

The macular mutant mouse is a murine model of the Menkes' kinky hair disease, characterized by a copper deficiency in serum. The immune response of its hemizygote (ml/y) was examined, herein. Ml/y mice which were not treated with Cu were atrophy of lymphoid tissues on day 14. However, kidney, brain, heart and lung weights were higher in ml/y mice without Cu treatment than in normal (+/y) mice. When compared to cells from +/y mice, spleen cells from ml/y mice exhibited similar proliferation-curves stimulated by Con A or LPS. Lymph node cells from ml/y mice showed a significantly decreased mixed lymphocyte reaction (MLR) response when stimulated by spleen cells from Balb/c mice. Spleen cells from ml/y mice demonstrated similar stimulation against lymph node cells from Balb/c mice. Antibody production against sheep red blood cells (SRBC) in vivo, a T cell dependent response, was suppressed in ml/y mice. By contrast, the antibody production against dinitrophenyl-ficoll, a T cell independent response was similar in +/y and ml/y. The antibody production against SRBC in vitro was also suppressed in ml/y mice. However, when the T cell-enriched fraction of ml/y mouse spleen cells was replaced by the T cell-enriched fraction of +/y mouse spleen cells, the antibody production against SRBC was recovered. The percentage of Ly-5-positive cells (B cell) from ml/y mice was greater than those from +/y mice. The percentage of Thy-1.2-positive cells (T cell) was decreased, and the decrease was most prominent with the L3/T4-positive T cell (helper T cell) subset.

Prenatal evaluation and obstetrical management of fetuses at risk of developing lung hypoplasia

The aim of this study was to measure the fetal lung area of normal human fetuses using ultrasound and them to test the predictive values of a nomogram in the identification of fetal lung hypoplasia. A nomogram for ultrasound-measured fetal lung area were constructed from 264 normal fetuses from 17 to 39 weeks of gestation. In 19 cases running the risk of developing lung hypoplasia, the sensitivity, specificity, and positive and negative predictive values of lung area measurements below the mean -2 SD were 75%, 100%, 94% and 100%, respectively, with total lung area showing a significant relation to the combined lung weight (Y = -1.05 + 2.06 X, r2 = 0.88). These results indicate that lung area measured by ultrasound is a good indicator of lung weight, and this nomogram of lung area may be useful in evaluating lung growth prenatally, as well as in the direct obstetrical management of fetuses at risk of developing lung hypoplasia.

[A müllerian duct cyst treated by injection of minocycline: a case report]

A 29-year-old male was admitted for the examination of left flank pain. Abdominal ultrasonography revealed a cystic mass beneath the urinary bladder. Computed tomographic scan, magnetic resonance imaging and transrectal ultrasonography showed that this cystic mass was located between the bladder and the prostate. DIP, urethrocystography and seminal vesiculography demonstrated no communication between this mass and the urinary and the seminal tract. From these findings it was diagnosed a müllerian duct cyst. We obtained 15 ml of clear yellowish fluid which contained no sperm by fine needle aspiration under ultrasound guidance and injected minocycline for sclerotherapy. Left flank pain had disappeared and repeated ultrasonography showed a small cystic lesion. However, the size of the cyst was unchanged for six months after discharge. Twenty-five müllerian duct cysts reported in the Japanese literature were reviewed.

Rapid axonal transport velocity is reduced in experimental ethylene oxide neuropathy

Chronic exposure of rats to ethylene oxide (EO) causes distal axonal neuropathy of lumbosacral primary sensory neurons. To study the pathogenesis of this neuropathy, we measured rapid axonal transport in peripheral nerves. Rats were exposed for 6 h to 500 ppm EO in a chamber three times a wk for 15 wk. Rapid axonal transport and quantitative histological alterations of peripheral nerves were studied. After [35S]methionine injection into the dorsal root ganglion, the velocity of rapid anterograde axonal transport of radioisotope-labeled protein was measured. The velocity in the rats exposed to EO was 33% less than that in control rats exposed to filtered room air. However, histological differences were slight. Morphometric studies showed that in EO-exposed rats, only the distal portions of the sural nerve had significantly greater incidental degeneration of myelinated fibers than did controls. There were significantly fewer large myelinated fibers only in the distals peroneal nerve. Therefore, a decrease in the velocity of anterograde axonal transport, related to these slight histological abnormalities of the peripheral nerve, may play a causative role in the development of the distal axonal neuropathy owing to chronic EO exposure.

[Investigation of the incidence of aberration in various indication for prenatal cytogenetic analysis]

In order to evaluate the role of prenatal cytogenetic analysis for the management of pregnant women, we studied the incidence of chromosomal aberration in 1,258 cases. In 502 cases with advanced maternal age (at least 35 years older), 12 (2.4%) cases of chromosome aberration were detected. The incidence of chromosomal aberration in the cases with women who had a previous child with chromosome aberration, women who had given birth to a congenital malformation child, and women who had ultrasonographic abnormalities were 3.0% (8/271), 0% (0/103) and 11.7% (36/307), respectively. Of cases with advanced maternal age, the incidence of chromosome aberration is 0% (0/21) at age 35, 0% (0/22) at age 36, 19% (1/52) at age 37, 2.2% (2/92) at age 38, 10% (1/102) at age 39, 1.3% (1/75) at age 40, 5.3% (3/56) at age 41, 6.9% (3/43) at age 42, 4.4% (1/23) at age 43 and 6.7% (1/15) at age 44. These results indicate that the incidence of chromosome aberration increases with maternal age. On the basis of these data, we recommend medical practice to offer prenatal diagnosis to all women who will be 37 or older. In the cases of fetal anomaly, they were diagnosed by ultrasonographic examination, the high incidence of chromosome aberration was detected in comparison with another group. Therefore, the prenatal cytogenetical analysis may also be performed in these cases.

How blood viscosity influences changes in circulation during pregnancy?

The changes of whole blood viscosity and plasma viscosity were studied in 15 normal non-pregnant women, and 120 normal pregnant women ranging from 8 to 39 weeks of gestation. The values of whole blood viscosity during normal pregnancy were significantly lower from 20 to 31 weeks of gestation than those in the other periods of gestation, and there was a positive correlation between whole blood viscosity and hematocrit. Plasma viscosity, however, did not change significantly during pregnancy. There was no correlation between whole blood viscosity and plasma viscosity, and there was also no correlation between plasma viscosity and plasma fibrinogen concentration. These findings suggest that decreases in whole blood viscosity, resulting from the change of packed-cell volume, may strongly contribute hemorheologically to the decrease in peripheral resistance during the second trimester.

Role of platelet activating factor on the fibrinolytic activation in the pathogenesis of gastric mucosal damage induced by endothelin-1

We have examined the hypothesis that the release of tissue type plasminogen activator may play a prominent role in endothelin induced gastric mucosal injury. We determined tissue type plasminogen activator activity in the regional blood sample and the concentration of platelet activating factor in the gastric mucosa after the administration of endothelin-1 in a range of 50-500 pmol/kg into the left gastric artery of male Wistar rats. Endothelin-1 increased the tissue type plasminogen activator release and platelet activating factor formation, and induced subsequent gastric mucosal haemorrhagic change in a dose dependent manner. In addition CV-6209, a selective platelet activating factor blocker, attenuated the activation of regional tissue type plasminogen activator and the development of mucosal damage induced by endothelin-1. The results of this study showed that tissue type plasminogen activator activation may play an important role in the pathogenesis of endothelin induced mucosal injury of rat stomach, and suggest that the platelet activating factor may be involved in the process of regional fibrinolytic activation induced by endothelin-1.