No enhancement by nitric oxide of glutamate release from P2 and P3 synaptosomes of rat hippocampus

Effects of nitric oxide on glutamate (Glu) release in long-term potentiation (LTP) were investigated by superfusion of conventional (P2) and large (P3) synaptosomes prepared from the rat hippocampus. Basal releasing rates of endogenous Glu from P2 and P3 fractions were 103.6 and 85.2 pmol/min/mg protein, respectively. Exposure to a depolarizing concentration of KCl (30 mM) evoked 3.58- and 4.52-fold increases in releasing rates of Glu from P2 and P3 fractions, respectively. Although the perfusion with sodium nitroprusside (NP, 10(-3) M), a nitric oxide-releasing agent, failed to augment the K(+)-evoked releases of Glu from P2 and P3 synaptosomes, NP enhanced that from slices of the hippocampus by 39% without changing basal release. Similarly, 8-bromoguanosine 3':5'-cyclic monophosphate (10(-4) M) increased the K(+)-evoked release of Glu from slices by 30%, but not from either synaptosomes. When synaptosomes were prepared from the hippocampus which was pretreated with two trains of electrical field stimulation (100 Hz, 0.1 ms, for 2 s), K(+)-evoked releases of Glu from P2 and P3 synaptosomes were increased by 15% and 23%, respectively. Although nitric oxide is postulated to function as a retrograde messenger to maintain LTP, present results suggest that nitric oxide may not directly act upon nerve terminals to enhance glutamate release, but that interventions of glias and short neurons may be involved in the presynaptic mechanism of LTP.

Effects of low-dose X-ray irradiation on biomembrane in brain cortex of aged rats

We previously found that low-dose X-ray irradiation or radon (weak alpha-ray) inhalation increases SOD activities and reduces lipid peroxide levels in various organs of 7-week-old rats or rabbits. In this study, we examined how the changes of SOD activity, lipid peroxide level, and membrane fluidity of the cerebral cortex in aged male Wistar rats (65 and 91 weeks old) were affected by low-dose X-ray irradiation (100 cGy or under) compared with those in 7-week-old rats, to elucidate the mechanism of aging inhibition. The following results were obtained: Although radiation sensitivity was observed to decreases with age, low-dose irradiation changed the Mn-SOD activity, lipid peroxide level, and membrane protein fluidity parameter of the cerebral cortex in the age rats to be closer to those in the youth. These findings suggest that the increased SOD activity induced by low-dose irradiation enhances biomembrane functions, and that the decrease of lipid peroxide level enhances the membrane protein fluidity.

[Contamination of healthy livestock with verocytotoxin producing Escherichia coli (VTEC), the first isolation from goats in Japan]

As part of the investigation on the source and route of infection with Verocytotoxin producing Escherichia coli (VTEC) in human beings, isolation of VTEC was attempted using fresh feces collected from healthy livestock (cattle, swine and goat) raised in Sagamihra, Yokohama and Hiratsuka cities from October, 1991 to March, 1992. VTEC could be isolated from 1 (1.0%) of 105 swine, 2 (3.6%) of 55 cattle and 2 (15.4%) of 13 goats. VTEC was isolated for the first time from goats in Japan. The combinations of the serotype and toxin type of the isolated strains were O116:H21 (VT2) and O163:H19 (VT2) for those isolated from the cattle, OUT:H19 (VT2vp) for that from the swine and OUT:H21 (VT1) for those from the goats. Since VTEC isolated from the cattle and goats were found to produce VT of the same serotypes as human VTEC, domestic animals were considered to be involved as a source of VTEC infection in human beings.

Detection of intrarenal venous invasions of malignant renal neoplasms by retrograde renal venography

The purpose of this study was to detect intrarenal venous invasion of malignant renal neoplasms not detected by other methods, with retrograde renal venography using a renal artery obstructing balloon. By this method, we studied 21 patients with malignant renal neoplasms, and clearly demonstrated the intrarenal branches up to the interlobar veins in all of these cases without any complications. This method detected small intrarenal venous lesions in three cases of renal cell carcinoma.

A rare portosystemic shunt detected by MRI and diagnosed by dynamic liver scintigraphy with Tc-99m phytate

Although various types of portosystemic shunts with portal hypertension have been widely reported, a collateral circulation near the pancreas head is rare. The authors report a case of a rare portosystemic shunt surrounding the pancreatic head, which was diagnosed by dynamic liver scintigraphy using Ikoma's scintigraphic criteria for the presence of portosystemic shunts. According to these criteria, abnormal accumulation of radioactivity at various abdominal sites (not identified on static images after the dynamic study) on 6 or more continuous frames of 5-second intervals (i.e., for 30 seconds or more after the arterial phase) indicates the presence of a portosystemic shunt. If liver scintigraphy is performed on a patient with portal hypertension, the dynamic study is valuable in the detection and diagnosis of a portosystemic shunt.

[A surgical treatment of ruptured arch aneurysm]

A 83-year-old woman was admitted to our hospital because of back pain and shock. Her chest X-ray and CT scan demonstrated a large arch aneurysm and hemothorax, suggesting ruptured aortic arch aneurysm. The ruptured aortic arch aneurysm was replaced with a woven Dacron graft under selective cerebral perfusion (SCP). Her postoperative course was uneventful without any neurological deficits. For the past three years, we have utilized SCP in 12 cases of arch aneurysms. There were three early deaths in this series. The cause of death were bleeding in one patient and cerebral accident in two patients. The latter two patients had severe atheromatous changes in the aortic wall. The SCP technique was a useful method of cerebral protection, especially for elderly patient with aortic arch aneurysm.

Paradoxical embolism as a cause of ischemic stroke of uncertain etiology. A transcranial Doppler sonographic study

BACKGROUND AND PURPOSE

This study was designed to test the hypothesis that paradoxical embolization would be a cause of embolic strokes and transient ischemic attacks in patients with stroke of uncertain etiology in all age groups.

METHODS

Thirty patients who had stroke of uncertain etiology were studied. They were divided into the following three groups: 13 patients with sudden onset (group A), 11 patients with subacute onset (group B), and 6 asymptomatic stroke patients (group C). Eleven patients with stroke of obvious etiology (group D) and 11 normal healthy volunteers (group E) were also studied as controls. In all patients transcranial Doppler sonography and contrast echocardiography were recorded simultaneously after intravenous injection of the contrast medium. Findings of positive patient foramen ovale in contrast echocardiography or "chirp" sounds in transcranial Doppler sonography were defined as positive for paradoxical contrast embolization. Radioisotope phlebography of the lower extremities and pulmonary scintigraphy, using technetium-99 macroaggregated albumin, were performed in all 17 patients who had positive findings of paradoxical contrast embolization and in 12 patients whose findings were negative.

RESULTS

Positive findings of paradoxical contrast embolization were found in 17 subjects by transcranial Doppler sonography but in only 8 on contrast echocardiography. These positive findings were detected more frequently in group A (77%) than in groups B, D, and E (9%, 18%, and 9%, respectively) (P < .05). In group C, 4 of 6 patients (67%) had positive findings. There were positive findings on both phlebography and pulmonary scintigraphy only in 6 group A patients, with positive findings of paradoxical contrast embolization.

CONCLUSIONS

Transcranial Doppler sonography is a sensitive detector of right-to-left shunts. Paradoxical cerebral embolization might be frequent in patients with stroke of unknown etiology, especially when the stroke is of sudden onset.

[The role of flagella of Campylobacter jejuni in colonization in the intestinal tract in mice and the cultured-cell infectivity]

For analyzing the role of the bacterial flagella in colonization in the intestinal tract of mice and adhering to or invading the Intestine 407 cell, a nonflagellated, nonmotile mutant was induced by ultraviolet irradiation of a flagellated, motile wild-type strain of Campylobacter jejuni CF84-340. There was no great difference in the cellular infectivity to the Intestine 407 cells between the wild-type and the mutant strains. Cellular adherence and invasiveness were then compared by fluorescent antibody staining, and an obvious difference was found in the latter. While 21.4% of the organisms of the wied-type strain invaded the cells, only 6.1% of those of the flagella-defective mutant did so. In the experiments in mice involving oral administration, cellular invasiveness was not found with the flagella-defective mutant and no organisms were detected from the blood, although bacteremia is one of the characteristics of infection with C. jejuni. Moreover, no intestinal adherence of the mutant was detected, suggesting early elimination of the organism administered. These results indicate that the bacterial flagella are concerned in not only the cellular adherence and intestinal deposit, but also the intracellular invasiveness and invasion into the blood stream from the intestinal wall in the infected mice.

[A successful case report of coronary artery bypass grafting under ventricular fibrillation with circulatory arrest]

Coronary artery bypass grafting in a 78-year-old female with severely calcified ascending aorta was performed successfully. Bilateral internal thoracic arteries and saphenous vein were anastomosed under ventricular fibrillation and hypothermia without aortic cross-clamping. Proxymal anastomosis of saphenous vein graft was performed directly under circulatory arrest in a normal part of ascending aorta which was confirmed by intraoperative ultrasonography. Weaning from ECC was easy and no neurological complication was observed after operation. Bypass grafts were patent on postoperative coronary angiogram and postoperative course was uneventful. We think the technique of circulatory arrest and intraoperative ultrasonography were useful in a patient with severely calcified ascending aorta.

[Evaluation of combination chemotherapy for advanced gastric carcinoma as a neoadjuvant chemotherapy with CDDP, MMC, etoposide and 5'-DFUR]

Seven cases of nonresectable gastric carcinoma with lymph node metastasis were treated with combination chemotherapy [CDDP 75 mg/m2 i.v. day 1 (A method: Ccr > or = 50 ml/min) or 20 mg/m2 i.v. day 1, 2, 4, 5 (B method: Ccr < 50 ml/min), MMC 10 mg/m2 i.v. day 1, etoposide 50 mg/body i.v. day 3, 4, 5, 5'-DFUR 2,100 mg/body po 4 day/week] every 4 weeks as a neoadjuvant chemotherapy. After treatment, the size of the primary tumor was reduced in four of seven cases. The lymph nodes disappeared in one case and were reduced in size in four cases. Metastatic liver tumors were found in four cases. They disappeared in one case and the size was reduced in one of seven cases. One patient with renal dysfunction was treated with B method. However, renal dysfunction did not become worse. Five patients were operated after chemotherapy. Absolute curative resection was performed in three of them. The total rate of curative resection was 43% (3/7). Four patients were alive for 19 months after operation. The main side effects of this therapy were nausea, anorexia and bone marrow suppression, which, were found in all patients. These results suggest that this combination chemotherapy is as effective as neoadjuvant chemotherapy for advanced gastric carcinoma.

[Evaluation of the biological malignancy in hepatocellular carcinoma by argyrophilic nucleolar organizer region (AgNOR) staining--morphological study of AgNOR using image analyzer]

Using the Colloid silver staining technique to reveal AgNOR and immunostaining for anti-PCNA monoclonal antibody, 23 resected specimens with hepatocellular carcinoma (HCC, < or = 3.5cm in diameter) were examined. These cases were divided into two groups; Group A [9 cases without vascular invasion and a satellite nodule] and Group B [14 cases with satellite nodules]. Comparison of AgNOR score, the morphological features of AgNOR (the area and roundness factor of AgNOR) and PCNA labeling index between Group A and Group B was made by a image analyzer (SP-500). The AgNOR scores and PCNA labeling indices of HCCs in Group B were significantly higher than those of HCCs in Group A. And a close correlation was shown between AgNOR score and PCNA labeling index. Further more, the area, form, and distribution of AgNORs within the nucleus were also different in the two study groups. In Group A, many AgNORs were regular and medium-sized brown dots (AgNOR-roundness factor; > or = 80%, AgNOR-area; 1.5-4.5 microns 2). But in Group B, AgNORs showed marked variation in size and form. These results suggest that HCCs with multiple, smaller, irregular, and widely dispersed AgNOR in combination with high AgNOR scores have a more aggressive potential. The morphological features of AgNOR may be useful indicators for evaluating the proliferative activity of HCC.

Asymptomatic carotid lesions and silent cerebral infarction

BACKGROUND AND PURPOSE

Few studies have investigated the relationships between asymptomatic carotid lesions and silent infarcts confirmed on magnetic resonance imaging.

METHODS

A consecutive series of 117 subjects (average age, 62 +/- 9.4 years) who were free from neurological deficit but had at least one established risk factor for stroke were investigated by B-mode carotid ultrasonography and magnetic resonance imaging of the brain. Carotid lesions were evaluated by plaque score, maximum percent stenosis, and the existence of ulcerated lesions. The relations between the carotid lesions and the incidence, size, or localization of the brain lesions were investigated.

RESULTS

The incidence of silent infarcts was 42% in all subjects and significantly increased with advancing age (P < .05). Most lesions were smaller than 1 cm in diameter and were usually localized in the subcortical white matter or the basal ganglia. The percentage of subjects with infarcts increased significantly as the plaque score increased (P < .05) or when subjects had high-grade stenosis (P < .05) or ulcerated lesions (P < .01). These relationships were also noted in each decade of age. A higher incidence of larger lesions (> 1 cm) was found in the brain hemisphere ipsilateral to the carotid lesion, particularly in subjects with high-grade stenosis or ulcerated lesions (P < .01). Multivariate analysis indicated significant correlations with silent infarcts for age, hypertension, and plaque score.

CONCLUSIONS

Both the severity and characteristics of asymptomatic carotid lesions estimated by B-mode ultrasonography were closely related to the appearance of silent infarcts. These results demonstrate that noninvasive assessment of carotid lesions can be useful in predicting the existence of silent cerebral infarction even in patients free from neurological deficits.

Studies on dissolution tests for soft gelatin capsules. IV. Dissolution test of nifedipine soft gelatin capsule containing water soluble vehicles by the rotating dialysis cell method

The dissolution of oval soft gelatin capsules containing 5 mg of nifedipine dissolved in a water soluble vehicle was evaluated by the rotating dialysis cell (RDC) method and the paddle (PD) method as described in the Japanese Pharmacopoiea (JP) XI. The dissolution pattern of nifedipine obtained by the PD method was linear, and almost 100% of the content was dissolved within 7 to 10 min. The dissolution pattern obtained by the RDC method corresponded to the absorption pattern vs. time curve obtained by th oral administration test in humans. When the RDC method was performed with the cell containing a buffered solution coupled with n-octanol as the dissolution medium, the in vitro dissolution pattern best simulated the in vivo absorption pattern.

[A concomitant operation of Damus-Kaye-Stansel procedure, atrioventricular valvuloplasty and total cavopulmonary connection]

A 2-year-old girl with single ventricle and coarctation of aorta, who received subclavian flap aortoplasty and pulmonary artery banding at 30 days of age, developed subaortic stenosis and atrioventricular valve regurgitation. At the age of 2 years and 10 months, physiologic correction with atrioventricular valvuloplasty, Damus-Kaye-Stansel procedure, and total cavopulmonary connection were performed concomitantly. She showed uneventful convalescence, and postoperative cardiac catheterization revealed trivial atrioventricular valve regurgitation with a mild pressure gradient between the left ventricle and aorta.

[Successful patch angioplasty for the right coronary artery dissection following selective coronary perfusion]

A case of successful patch angioplasty for the right coronary artery (RCA) orifice dissection following selective coronary perfusion is reported. A 56-year-old woman who had mitral restenosis, aortic stenosis, and atrial fibrillation with bradycardia-tachycardia syndrome was referred to our hospital for operation. The operation, which contained aortic valve replacement and mitral commissurotomy, was performed with hypothermic cardiopulmonary bypass and crystalloid cardioplegic arrest. The ascending aorta was opened, and selective coronary perfusion was performed. The right coronary cannula was difficult to insert and dislodged several times. At the second infusion of the cardioplegic solution, the right coronary orifice and ascending aortic wall was dissected. The dissection extended to the proximal RCA. The aortotomy was extended into the RCA beyond its orifice. The Xenomedica pericardial patch was used to enlarge the diameter of the RCA with closing the dissected cavity. Then the patch was brought onto the side of the aorta and the aortotomy was closed in the usual manner. Post operative coronary angiography revealed widely patent RCA orifice and good runoff. Two years after operation the patient is free of angina with unlimited physical activity.

Hashimoto thyroiditis, distal renal tubular acidosis, pernicious anaemia and encephalopathy: a rare combination of auto-immune disorders in a 12-year-old girl

A case of a 12-year-old girl with a multiple auto-immune disorder is reported. She showed Hashimoto thyroiditis which subsequently developed to hashitoxicosis and distal renal tubular acidosis at 5 years of age, pernicious anaemia at the age of 9 and severe encephalopathy at the age of 12. Laboratory studies revealed very high titres of anti-microsomal and anti-thyroglobulin antibodies and positive gastric parietal cell antibody. As to the encephalopathy, positive oligoclonal IgG bands and high values of IgG index and IgG synthesis ratio in CSF were observed with aggravation of her neurological symptoms. High-dose steroid therapy was effective toward the encephalopathy. Paediatricians should pay careful attention to patients with Hashimoto thyroiditis for association with other autoimmune disorders.

MKC-231, a choline uptake enhancer, ameliorates working memory deficits and decreased hippocampal acetylcholine induced by ethylcholine aziridinium ion in mice

The effects of acute and chronic administration of MKC-231, a new choline uptake enhancer, and two other nootropic agents, linopiridine (Dup 996) and tetrahydroaminoacridine (THA) on working memory deficits and decreased hippocampal acetylcholine (ACh) content were studied in a delayed non-matching to sample task, using a T-maze, in ethylcholine aziridinium ion (AF64A)-treated mice. Treatment with AF64A (3.5 nmol, i.c.v.) produced memory deficits and decreased hippocampal ACh content. In acute behavioral experiments, MKC-231 and THA had no significant effect on AF64A-induced memory deficits at any doses tested (0.3, 1.0 and 3.0 mg/kg), whereas Dup 996, at a dose of 1.0 mg/kg, significantly improved memory deficits. In chronic experiments, MKC-231 improved memory deficit at all doses tested (0.3, 1.0, or 3.0 mg/kg p.o., once daily for 11 days) and Dup 996 did so only at a dose of 3.0 mg/kg, whereas THA did not improve memory deficit at any doses tested. In acute neurochemical experiments, MKC-231 and THA did not reverse the AF64A-induced hippocampal ACh depletion. Dup 996, however, further decreased hippocampal ACh content compared to that in the AF64A-treated group. In chronic experiments, MKC-231 significantly reversed hippocampal ACh depletion at doses of 0.3 and 1.0 mg/kg, whereas neither Dup 996 nor THA reversed hippocampal ACh depletion at any doses tested. These results indicate that MKC-231 improved the AF64A-induced working memory deficit and hippocampal ACh depletion, probably by recovering reduced high-affinity choline uptake and ACh release.

Reactivity of cerebral blood flow to carbon dioxide in hypertensive patients: evaluation by the transcranial Doppler method

OBJECTIVE

To evaluate hypertensive cerebral involvement before cerebrovascular accidents.

DESIGN

Cerebral microvascular responses to changes in the arterial partial pressure of CO2 (pCO2; the CO2 reactivity) were compared among patients with different stages and severity of hypertensive disease.

PATIENTS

Fifty-eight patients with hypertension, 11 with borderline hypertension, 15 hypertensives with cerebral infarction and 58 normotensive controls were studied.

METHODS

The cerebrovascular CO2 reactivity was determined by measuring simultaneously the end-tidal pCO2 and the blood flow velocity in the middle cerebral artery using transcranial Doppler sonography under hypocapnic, normocapnic and hypercapnic conditions.

RESULTS

CO2 reactivity was impaired in the hypertensive patients compared with in the normotensive controls, but less so than in the symptomatic hemisphere of the hypertensive patients with cerebral infarction. The CO2 reactivity in the borderline hypertensive patients was greater than that in both the symptomatic and asymptomatic hemispheres of the hypertensive patients with cerebral infarction. In the subjects without cerebral infarction, two risk factors for cerebral atherosclerosis (age and hypertension) were negatively correlated with cerebrovascular CO2 reactivity. In the hypertensive patients age and the estimated duration of hypertension were negatively correlated with cerebrovascular CO2 reactivity. CO2 reactivity in the patients with hypertensive or arteriosclerotic retinopathy or ST-T changes on their electrocardiogram was impaired compared with that in the patients without such changes.

CONCLUSIONS

Hypertension affected the microvascular reactivity of the brain before the development of cerebrovascular accidents, and its effect varied dependently on the extent of involvement of other target organs.

Cytoplasmic membrane-associated protein (CAP) isolated from Streptococcus pyogenes: as a new bacterial superantigen

A protein isolated from the cytoplasmic membranes of Streptococcus pyogenes (cytoplasmic membrane-associated protein, CAP) stimulated human T cells in vitro to induce their mitogenic response. This CAP-induced T cell proliferation required the presence of nylon-adherent accessory cells (AC) of either autologous or allogeneic origin in the reaction mixtures. In addition, the reaction was inhibited by monoclonal antibodies (mAbs) against major histocompatibility complex (MHC) class II molecules, HLA-DR and -DQ, but not -DP. Human lymphoid cell lines positive for HLA-DR but not those lacking it were also effective as AC for the reaction. A binding test using fluorescein-labeled protein revealed that CAP bound to the adherent monocytes and HLA-DR+ but not to -DR- lymphoid cell lines. The proliferative response of T cells to CAP was, however, not inhibited by the addition of the lysosomotrophic agent NH4Cl to the reaction mixtures. These results suggest that the presentation of CAP by AC to human T cells is mediated through binding of the protein to the MHC class II molecules but without being processed in the AC. The proliferative response of T cells was also found to be inhibited by addition of anti-CD2, -CD3 or -T cell receptor (TcR) mAbs. A major population responding to CAP was CD3+4+8- T cells. CAP also appears to stimulate T cells bearing V beta 8 sequences much more selectively than T cells bearing other V beta s. These results indicate that this streptococcal membrane protein, CAP, may be a new protein belonging to a group of bacterial superantigens.

A new approach for aortocaval fistula from ruptured abdominal aortic aneurysm. Balloon occlusion technique under echogram guidance

Aortocaval fistula is a rare but well-recognized complication of abdominal aortic aneurysms. However, it is difficult to make preoperative diagnosis due to various clinical findings in a patient. Once the diagnosis is made surgical treatment is urgently required. Successful surgical therapy depends on control of bleeding from the fistula. We used two Forgaty balloon catheters inserted into the inferior vena cava under echogram guidance, thus restricting bleeding from the fistula. This new approach is safe and useful for intraoperative control of hemorrhage from a ruptured abdominal aortic aneurysm.

Determination of carbenicillin epimers in plasma and urine with high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for determining the concentrations of carbenicillin (CBPC) epimers in plasma and urine. Samples were prepared for HPLC analysis by solid-phase extraction and the concentrations of CBPC epimers were determined using reversed-phase HPLC with a mixture of 0.05 M ammonium acetate and methanol as a mobile phase. Baseline separation of the two epimers was observed for both plasma and urine samples with a detection limit of ca. 10 micrograms/ml. No peaks interfering with either of the CBPC epimers were observed on the HPLC chromatograms for blank plasma and urine. The presented method was used to determine the protein binding of CBPC epimers in vitro in human and rabbit plasma. The stereoselectivity of the binding of CBPC appeared to be reversed in human and rabbit plasma.

Not only osmotic stress but also repeated restraint stress causes structural plasticity in the supraoptic nucleus of the rat hypothalamus

Magnocellular neuroendocrine cells (MNCs) in the supraoptic nucleus (SON) of the hypothalamus have been known to undergo dramatic structural changes during chronic stimulation such as osmotic stress. In the present study, we examined whether this anatomical neural plasticity is associated with an another stress, such as restraint. Rats were chronically stimulated by either dehydration with 2% saline drinking instead of water or daily restraint with leg immobilization. The structural reorganizations of MNCs in the SON were analyzed morphometrically with use of light and electron microscopy. The results were compared to control animals that had free access to water and food. In restraint rats, the soma size of both oxytocin (OXT) and arginine vasopressin (AVP) neurons was enlarged, and the percent of soma-somatic/dendritic membrane contact (juxtaposition) was elevated significantly. The number of total synapses per 100 microns soma membrane was not changed, although soma profiles were enlarged. However, the number of multiple synapses (which contacted with more than one postsynaptic element) per 100 microns soma membrane was significantly increased. Similar structural changes were observed in dehydrated animals, and the degree of morphological changes was stronger than the restraint one. These findings indicate that NMCs undergo structural plasticity during not only osmotic stress but also restraint stress.

Estradiol-17 beta regulates the induction of VCAM-1 mRNA expression by interleukin-1 beta in human umbilical vein endothelial cells

We examined the effect of estradiol-17 beta on the expression of vascular cell adhesion molecule-1 (VCAM-1), an adhesion molecule, in human umbilical vascular endothelial cells. After preincubation with estradiol-17 beta for 24 hours, cells were treated for 4 h with 0.5 micrograms/ml recombinant human interleukin-1 beta. The RNase protection assay was performed using an [alpha-32P]-labeled 121 base pair VCAM-1 cRNA probe. Preincubation with estradiol-17 beta (250 or 500 pg/ml) suppressed the induction of VCAM-1 mRNA expression by interleukin-1 beta. VCAM-1 staining with a monoclonal antibody decreased when cells were incubated with estradiol-17 beta at 250 and 500 pg/ml, while staining was detectable when cells were treated with interleukin-1 beta at 0.5 micrograms/ml. In conclusion, estradiol-17 beta regulates the induction of VCAM-1 gene expression by interleukin-1 beta in human umbilical vein endothelial cells.

Gestational changes in endothelium-dependent vasorelaxation in human umbilical artery

OBJECTIVE

We intended to clarify whether (1) the amount of endothelium-derived vasorelaxing factor or nitric oxide released by histamine is sufficient to cause relaxation in human umbilical artery at different stages of gestation and (2) the functional role of endothelium-derived relaxing factor changes with the progress of gestation.

STUDY DESIGN

By means of a bioassay cascade technique with very thin muscle strips, which allows rapid diffusional access of applied drugs (of the order of a few seconds), contractile properties were examined.

RESULTS

At 18 to 22 weeks of gestation histamine produced only a minor contraction, but as gestation progressed the contractile responses increased. L-NG-nitro-arginine greatly enhanced the histamine-induced contractions. Histamine produced a concentration-dependent relaxation during the maintained contraction induced by 39 mmol/L K+ in tissues from 18 to 22 weeks or 30 to 32 weeks but not 38 to 41 weeks of gestation. Thus the concentration-relaxation relationship for histamine showed decreased sensitivity during gestation. The histamine-induced relaxation was enhanced by superoxide dismutase and completely blocked by L-NG-nitro-arginine or mepyramine (H1 antagonist). The concentration-relaxation relationship for the action of glycerol trinitrate relaxation decreased as gestation progressed. In a bioassay cascade an endothelium-intact umbilical artery from 18 to 22 or 38 to 41 weeks of gestation was used as a "donor" and L-NG-nitro-arginine-treated umbilical artery from 18 to 22 and 38 to 41 weeks as a "detector." In the presence of histamine the perfusate that had passed through a donor from 18 to 22 weeks (but not 38 to 41 weeks) attenuated the high K(+)-induced contraction in the detector only from 18 to 22 weeks.

CONCLUSION

These results suggest that the amount of endothelium-derived relaxing factor and the sensitivity of smooth muscle to endothelium-derived relaxing factor decreased with the progress of gestation.