Screening of fungal beta-xylanases for production of acidic xylooligosaccharides using in situ reduced 4-O-methylglucuronoxylan as substrate

Fungal beta xylanases were screened for production of acidic xylooligomers from 4-O-methylglucuronoxylan. In situ reduced hardwood xylan was used as substrate because the products of neutral- and acidic-branched xylooligomers help define substrate specificity of the enzymes. Borohydride reduction in situ transformed 30% of 4-O-methyl-alpha-D-glucopyranosyluronic acid residues into 4-O-methyl-alpha-D-glucopyranosyl residues and reduced C-1 end groups in the xylan backbones. A total of ten beta-xylanase fractions from four fungi were partially purified by chromatography by anion exchange and molecular sieving, and graded qualitatively for enzymatic hydrolysis of the substrate. The yield of acidic xylooligomers was highly affected by whether alpha-glucuronidases were present in the beta-xylanase fractions. Some fractions gave free 4-O-methyl-alpha-D-glucopyranosyluronic acid, but none of the enzyme fractions could release free 4-O-methyl-alpha-D-glucose. Among the beta-xylanase fractions studied, xylanase II of Trichoderma viride was the best producer of aldotetraouronic acid [2-O-(4-O-methyl-alpha-D-glucopyranosyluronic acid)-D-xylotriose]. The results obtained suggested that there was a difference in the steric hindrance of the branch point on fungal beta-xylanases between 4-O-methyl-alpha-D-glucopyranosyl and 4-O-alpha-D-glucopyranosyluronic acid residues.

Season of birth of schizophrenics in a recent Japanese sample

An excess of schizophrenic births in winter or early spring is a well replicated finding in studies on Western populations. However, there are few studies on Asian populations, and their results are not consistent. We examined the seasonality of schizophrenic births in Japanese subjects (n = 1024) born between 1955 and 1960. Our results showed a significant inverse relationship between temperature and number of schizophrenic births, which is in line with the findings in Western populations. In our data, observed reduction of schizophrenic births in summer was more marked than excess births in winter. We suggest the possibility that birth in summer may have some advantage in brain growth early in life, which results in reducing the risk of developing schizophrenia.

Predictors of the efficacy of interferon therapy in chronic hepatitis C virus infection. Tokyo-Chiba Hepatitis Research Group

BACKGROUND & AIMS

The relative role of virus load and hepatitis C virus (HCV) subtype as predictor of the efficacy of interferon (IFN) therapy is still in dispute. To resolve this issue, a multicenter, randomized, prospective study of 272 patients with chronic hepatitis C but without cirrhosis was conducted.

METHODS

The patients were randomly assigned to two different dose groups: 6 million units (MU) or 9 MU IFN three times a week for 6 months. Serum HCV RNA levels and HCV subtypes were determined.

RESULTS

HCV RNA negativity rate at the completion of treatment with 9 MU IFN was higher than that with 6 MU (75% vs. 44%; P < 0.05). Virus eradication at 12 months after completion of treatment was higher in the 9 MU group than in the 6 MU group (36% vs. 25%; P < 0.05), especially in patients who had an intermediate virus load (10(4)-10(5) copies/mL by Amplicor monitor assay) (52% vs. 19%; P = 0.029). Virus eradication rate in patients with serotype 2 was higher than in those with serotype 1 for both regimens (6 MU, 53% vs. 15%; 9 MU, 76% vs. 29%; each P < 0.05).

CONCLUSIONS

This prospective study showed that virus load, HCV serotype, and IFN dose are important predictors of the virological response to IFN therapy but virus load is the most important factor influencing the efficacy of IFN.

[Fundus hypothermia inhibits retinal damage induced by visible blue light]

We evaluated the role of fundus hypothermia in modifying photic retinopathy. The fundus was cooled with a copper plate inserted behind the eyeball. The anterior end of the plate was chilled with dry ice. Retinal temperature was thus reduced to 30 and 33 degrees C. This cooling manipulation had no effect on body temperature, retinochoroidal architecture, or choroidal circulation. The fundus was then exposed to visible blue light at an irradiance of 8 mW/cm2 for one hour. Retinal damage developed in 9 out of 10 eyes after the exposure alone, and in 3 out of 10 eyes when retinal temperature was reduced to 30 degrees C. The incidence of light damage with the cooling manipulation was decreased significantly when compared to that of controls (p < 0.05). Contrary to this, 5 out of 5 retinas treated with hypothermia at 33 degrees C showed damage and there was no significant difference in the incidence from that of controls. This finding indicates that local hypothermia at 30 degrees C protects the retina from light damage and that a subtle temperature milieu plays a role in producing retinal damage.

An Nrf2/small Maf heterodimer mediates the induction of phase II detoxifying enzyme genes through antioxidant response elements

The induction of phase II detoxifying enzymes is an important defense mechanism against intake of xenobiotics. While this group of enzymes is believed to be under the transcriptional control of antioxidant response elements (AREs), this contention is experimentally unconfirmed. Since the ARE resembles the binding sequence of erythroid transcription factor NF-E2, we investigated the possibility that the phase II enzyme genes might be regulated by transcription factors that also bind to the NF-E2 sequence. The expression profiles of a number of transcription factors suggest that an Nrf2/small Maf heterodimer is the most likely candidate to fulfill this role in vivo. To directly test these questions, we disrupted the murine nrf2 gene in vivo. While the expression of phase II enzymes (e.g., glutathione S-transferase and NAD(P)H: quinone oxidoreductase) was markedly induced by a phenolic antioxidant in vivo in both wild type and heterozygous mutant mice, the induction was largely eliminated in the liver and intestine of homozygous nrf2-mutant mice. Nrf2 was found to bind to the ARE with high affinity only as a heterodimer with a small Maf protein, suggesting that Nrf2/small Maf activates gene expression directly through the ARE. These results demonstrate that Nrf2 is essential for the transcriptional induction of phase II enzymes and the presence of a coordinate transcriptional regulatory mechanism for phase II enzyme genes. The nrf2-deficient mice may prove to be a very useful model for the in vivo analysis of chemical carcinogenesis and resistance to anti-cancer drugs.

Pyridoxine refractory X-linked sideroblastic anemia caused by a point mutation in the erythroid 5-aminolevulinate synthase gene

To elucidate how pyridoxine-refractory X-linked sideroblastic anemia (XLSA) develops, we analyzed the erythroid-specific 5-aminolevulinate synthase (ALAS-E) gene of a patient with the anemia. The activity and amount of the enzyme in bone marrow cells of the patient were found to be approximately 5% of the normal control. We identified a point mutation, which introduces an amino acid substitution from Asp 190 to Val. In transient transfection analyses using quail fibroblasts, accumulation of aberrantly processed proteins, the sizes of which were larger than that of mature ALAS-E, was found in mitochondria. The proteins were reproducibly detected in assays combining in vitro transcription/translation of ALAS-E precursor and import of the precursor into isolated mouse mitochondria. These results suggest that the mutation causing pyridoxine-refractory XLSA affects the processing of the ALAS-E precursor, thus provoking instability of the ALAS-E protein.

Cleavage of viral RNA and inhibition of viral translation by hepatitis C virus RNA-specific hammerhead ribozyme in vitro

BACKGROUND/AIMS

A hammerhead ribozyme has been used as a new way to suppress specific gene expression. We designed hammerhead ribozymes directed against hepatitis C virus RNA, and investigated their cleavage efficiency and inhibitory effect on viral translation in vitro.

METHODS

Three hammerhead ribozymes bearing different cleavage sites in the core region of hepatitis C virus RNA (genotype 1b) were designed in this study. Ribozymes and the target hepatitis C virus RNA were synthesized by in vitro transcription. The cleavage efficiency was evaluated by the ribozyme cleavage assay. The inhibitory effect of the ribozyme on viral translation was further studied by the viral translation inhibition assay.

RESULTS

All ribozymes specifically cleaved the target RNA of 1217 bases at a physiological temperature in a dose-dependent manner, with the specific cleavage increasing with a longer incubation period. The target RNA was cleaved most efficiently by the ribozyme with the cleavage site located nearest to the initiation codon. In the viral translation inhibition assay, all ribozymes showed a significant inhibitory effect on viral translation. The ribozyme with the cleavage site located farthest from the initiation codon blocked viral translation most efficiently, and demonstrated almost 70 to 80% inhibition. For ribozymes with the T7 transcription terminator sequence, both the target RNA cleavage and the inhibition of viral translation tended to be achieved less efficiently by ribozymes with T7 terminator than by those without it.

CONCLUSIONS

These findings suggest that ribozyme-mediated hepatitis C virus RNA cleavage may serve as a new strategy in the treatment of hepatitis C virus infection.

[Efficacy of the TURBO-fluid attenuated inversion recovery spin echo sequence of MRI as a preoperative neuroradiological examination]

Whenever the extirpation of intracranial tumors is planned, neurosurgeons always keep their eyes on the cerebrospinal fluid (CSF) space around intracranial tumors. If enough space exists in the neighborhood of the tumors, the damage to adjacent parenchyma may be reduced by the procedure through the CSF space. A newly advanced MRI pulse sequence: the FLAIR (fluid attenuated inversion recovery) imaging, in which a long TE spin echo sequence is used with suppression of the CSF with an inversion pulse, displays the CSF space as a no-signal intensity area. There have been only a few reports, however, on the FLAIR pulse sequence of brain tumors as yet. We examined 34 cases of intracranial tumors by FLAIR images and analyzed the advantages and disadvantages of the FLAIR pulse sequence for decision making on tumor removal. Making use of the FLAIR pulse sequence, the CSF space is depicted as a no-signal intensity area and much more information about perifocal edema and the invasion area around the tumors can be provided than that provided by the other ordinary pulse sequences (T1 weighted images, T2 weighted images and Proton weighted images). Therefore, operative strategies can be more easily worked out on the FLAIR images. Furthermore, the difference between arachnoid and epidermoid is able to be detected on the FLAIR images. Nevertheless, on FLAIR images, the tumors without perifocal edema or invasion to adjacent parenchyma were not apparent and the difference between tumoral dissemination into multi-ventricular space and the periventricular artifact of FLAIR images could not be distinguished. The FLAIR pulse sequence has other artifacts like intraventricular flow related enhancement and so on. If the images are carefully checked up on the above-mentioned points, the FLAIR pulse sequence of MRI can not fail to be useful in making plans for operations on intracranial neoplasms.

[Clinical investigation of prostatic cancer patients who underwent radical prostatectomy: analysis of patients in the Tokai Urological Cancer Registry]

Between 1989 and 1991, 815 cases of prostatic carcinoma were registered in the Tokai Urological Cancer Registry. We investigated the clinical features and prognosis of 69 patients who underwent radical prostatectomy. The median age and clinical stage, were 65.9 +/- 4.7 years and A in 7 patients, 66.3 +/- 5.8 years and B in 31, 68.2 +/- 2.7 years and C in 26, 63.4 +/- 13.5 years and N(+) in 5. Neoadjuvant therapy consisting of endocrine therapy and chemoendocrine therapy was administered to 28 and 14 patients, respectively. In comparison to the clinical stage, pathologically, 4 cases (9.5%) showed downstaging or overstaging, 15 (35.7%) understaging and 23 (54.8%) accurate staging in the neoadjuvant therapy group, and, respectively, 2 (7.4%), 12 (44.4%) and 13 (48.2%) in the non-neoadjuvant therapy group. There was a significant difference in the pretreatment prostatic antigen (PA) value between pT0 and pT3 (p < 0.05), between pT0 and pN(+) (p < 0.01) and between pT2 and pN(+) (p < 0.05). In addition, the pretreatment PA value in the recurrence group was higher than that in the non-recurrence group in both neoadjuvant and non-neoadjuvant groups, with a significant difference (p < 0.01) in the neoadjuvant group. Cancer recurrence was noticed in 2 patients given non-neoadjuvant therapy and 3 given neoadjuvant therapy. There was no significant difference in the non-recurrence rate with the pathological stage either with or without neoadjuvant therapy. However, the non-recurrence rate in the neoadjuvant therapy group was higher than that in the non-neoadjuvant therapy group.

Propionibacterium acnes treatment diminishes CD4+ NK1.1+ T cells but induces type I T cells in the liver by induction of IL-12 and IL-18 production from Kupffer cells

LPS injection into normal mice does not induce liver injury, while the same treatment of Propionibacterium acnes-primed mice induces severe liver injury, indicating that P. acnes treatment renders the mice susceptible to LPS. Since IFN-gamma sensitizes macrophages to LPS, we investigated the mechanism of induction and activation of IFN-gamma-producing (type 1) T cells by P. acnes. Twenty percent of liver lymphocytes of C57BL/6 mice are CD4+ NK1.1+ T cells that promptly produce IL-4 in response to anti-CD3 in vitro. However, P. acnes treatment diminished these lymphocytes. Therefore, liver lymphocytes from P. acnes-primed mice showed reduced IL-4 production. Furthermore, P. acnes treatment induced CD4- type 1 T cells in the liver. Isolated P. acnes-elicited Kupffer cells produced IL-12 and to a lesser degree IL-18 in vitro. Injection of anti-IL-12 Ab totally abrogated these actions of P. acnes, while injection of anti-IL-18 Ab caused only partial abrogation. Thus, administration of P. acnes diminished CD4+ NK1.1+ T cells, but induced type 1 T cells in the liver by induction of IL-12 and IL-18 production. Injection of IL-12 (approximately 1,000 ng) dose dependently diminished CD4+ NK1.1+ T cells, but induced type 1 T cells. In contrast, injection of IL-18 (approximately 1,000 ng) failed, although injection of a much larger dose of IL-18 (10,000 ng) or IL-18 (approximately 1,000 ng) with suboptimal doses of IL-12 (1-100 ng) diminished CD4+ NK1.1+ T cells in a dose-dependent manner. Thus, P. acnes treatment renders the mice highly susceptible to LPS by induction and activation of type 1 T cells.

US-guided left-sided biliary drainage: nine-year experience

PURPOSE

The feasibility and safety of left-sided biliary drainage with ultrasound (US) guidance were studied prospectively.

MATERIALS AND METHODS

From July 1987 to July 1996, 208 consecutive patients underwent US-guided biliary drainage; all were evaluated for left-sided drainage. Drainage procedure was begun with puncture of the hepatic duct branch of the lateral segment of the left lobe when the branch was well visualized with US; otherwise, a right-sided approach was used. When the hepatic duct branch diameter was greater than 3 mm, puncture was performed with an 18-gauge needle; smaller branches were punctured with 21-gauge needles.

RESULTS

In 147 (71%) patients, the left hepatic duct branch was well visualized with US, and the branch diameter was greater than 3 mm. In these patients, left-sided drainage with use of an 18-gauge needle was successful. In 26 (12%) patients, the left hepatic duct branch diameter was less than 3 mm, and drainage was initiated with a 21-gauge needle. In six (23%) of these 26 patients, left-sided drainage was unsuccessful, but five of these patients underwent successful US-guided drainage from the right hepatic duct branch. Two patients died of septic shock within 72 hours of completed drainage. Three patients experienced severe hemobilia.

CONCLUSION

US-guided left-sided biliary drainage is a highly successful and safe method when the left hepatic duct branch diameter is greater than 3 mm.

Propionibacterium acnes treatment diminishes CD4+ NK1.1+ T cells but induces type I T cells in the liver by induction of IL-12 and IL-18 production from Kupffer cells

LPS injection into normal mice does not induce liver injury, while the same treatment of Propionibacterium acnes-primed mice induces severe liver injury, indicating that P. acnes treatment renders the mice susceptible to LPS. Since IFN-gamma sensitizes macrophages to LPS, we investigated the mechanism of induction and activation of IFN-gamma-producing (type 1) T cells by P. acnes. Twenty percent of liver lymphocytes of C57BL/6 mice are CD4+ NK1.1+ T cells that promptly produce IL-4 in response to anti-CD3 in vitro. However, P. acnes treatment diminished these lymphocytes. Therefore, liver lymphocytes from P. acnes-primed mice showed reduced IL-4 production. Furthermore, P. acnes treatment induced CD4- type 1 T cells in the liver. Isolated P. acnes-elicited Kupffer cells produced IL-12 and to a lesser degree IL-18 in vitro. Injection of anti-IL-12 Ab totally abrogated these actions of P. acnes, while injection of anti-IL-18 Ab caused only partial abrogation. Thus, administration of P. acnes diminished CD4+ NK1.1+ T cells, but induced type 1 T cells in the liver by induction of IL-12 and IL-18 production. Injection of IL-12 (approximately 1,000 ng) dose dependently diminished CD4+ NK1.1+ T cells, but induced type 1 T cells. In contrast, injection of IL-18 (approximately 1,000 ng) failed, although injection of a much larger dose of IL-18 (10,000 ng) or IL-18 (approximately 1,000 ng) with suboptimal doses of IL-12 (1-100 ng) diminished CD4+ NK1.1+ T cells in a dose-dependent manner. Thus, P. acnes treatment renders the mice highly susceptible to LPS by induction and activation of type 1 T cells.

Ameloblastoma of the mandible metastasizing to the orbit with malignant transformation. A histopathological and immunohistochemical study

We report here a case of ameloblastoma of the mandible with multiple local recurrences and metastasis to the orbit. The patient was a 63-year-old Japanese woman with visual disturbance of her right eye. Diagnostic imaging revealed a mass occupying the right orbital apex with partial intracranial involvement. She had been surgically treated for mandibular ameloblastoma 27 years previously, and the tumour had recurred three times in the past 5 years. The orbital tumour and recurrent ameloblastomas were investigated histopathologically and immunohistochemically. The tumour changed in morphology as it recurred, from follicular ameloblastoma without atypia to apparent malignant tumours disclosing undifferentiated or squamoid features. On immunohistochemical analysis, staining for cytokeratin was positive in the squamoid cells but not in the undifferentiated cells. Both histopathologically and immunohistochemically, the orbital tumour was almost identical to the undifferentiated recurrent tumour. The orbital tumour was distinct from the primary site or sites of recurrence of ameloblastoma, and we concluded that the mandibular ameloblastoma underwent malignant transformation with multiple recurrences and finally metastasized to the orbit.

[Inoperable esophageal carcinoma managed by combined chemotherapy (CBDCA, 5-FU and VDS) and radiotherapy]

Eleven inoperable patients with advanced esophageal carcinoma were treated with chemotherapy (carboplatin, 5-FU, vindesine) and concomitant radiotherapy. Two patients (T2) received this treatment due to their poor general condition and refusal of operation, and 9 patients for infiltration of tumor into the adjacent organs (T4). Administration of carboplatin (30 mg/body) and 5-FU (250 mg/body) together with radiotherapy (1.8 Gy/d) for 5 days a week was performed. This chemoradiation therapy was carried out for 5 consecutive weeks. In addition, vindesine (1-3 mg/body) was administered in the 1st and 4th week. After evaluation, endoscopic balloon dilatation was performed in 6 patients with stenosis of the esophagus. The general response rate was 80%. CR was noted in 2 patients of T2 but 1 patient of T4 developed severe leucopenia and immunosuppression, and died of septic MOF. All but the MOF case could take enough food orally following the endoscopic dilatation. The 1-year survival rate in the T4 group (45%) was significantly better than the non-treatment group (0%). In conclusion, this treatment is beneficial for patients with inoperable esophageal carcinoma to obtain a satisfactory QOL and survival rate.

[CT-guided biopsy of small lung nodules: usefulness of frozen-section pathologic diagnosis]

PURPOSE

To improve the diagnostic accuracy of computed tomography (CT)-guided biopsy of small lung nodules.

MATERIALS AND METHODS

The usefulness of fine-needle core biopsy combined with immediate frozen-section diagnosis by pathologists was prospectively studied. Forty-six biopsies of small lung nodules (less than 3 cm in greatest diameter) were performed under CT guidance in 46 patients with 31 malignant and 15 benign processes. Initial biopsy was always attempted with a 20 or 21G histological needle; tissue samples were sent to the pathology department immediately after biopsy for pathologic diagnosis of the frozen sections.

RESULTS

In 41 of 46 lesions (89.1%), sufficient material was obtained for diagnosis, permitting a correct final diagnosis. For malignancy, the sensitivity was 100%, whereas 81.8% of the benign lesions were diagnosed as specifically benign. Pneumothorax occurred in 41.3%.

CONCLUSION

Histological diagnosis using frozen sections is a useful adjunct for CT-guided biopsy of the chest.

[Vitamin K deficiency syndrome caused by antituberculous agents]

Vitamin K deficiency caused by antituberculous agents was examined in clinical patients and in experimental rats. When antituberculous agents given to the patients who had only total elental diet because of small intestinal dysfunction, a marked increase in plasma PIVKA-II and a decrease in thrombo-test value were observed. These changes were quickly normalized by administration of vitamin K, despite of succeeding or stopping of antituberculous agents. In rat experiments, effects of four agents (ethambutol, isoniazid, paraaminosalicylate, and rifampicin) on prothrombin time were studied. Among these agents, only rifampicin prolonged prothrombin time. This prolongation depended on drug doses and duration of administration. In addition to this hypoprothrombinemia, an increase in plasma PIVKA-II was also observed, and these changes were normalized within 24 hours of vitamin K administration. These data suggest that rifampicin inhibits vitamin K epoxide reductase interfering re-use of vitamin K and caused vitamin K deficiency in patients with total elental diet.

[Clinical statistics of living and cadaveric renal transplantation at the Department of Urology, Mie University School of Medicine]

A statistic survey was made on the clinical results of living and cadaveric renal transplantations performed at our department between October 1980 and June 1996. A total of 38 patients received 6 living and 32 cadaveric renal transplants. The graft and patient survival rates of a living renal transplantation were 83.3% and 100% at 3 years, respectively. The graft survival rate of cadaveric renal transplantation was 66.3% at 3 years and 56.0% at 5 years. In a cadaveric renal transplantation, patients with episodes of acute rejection within 12 months showed a significantly worse graft survival rate. This clinical parameter seems to be a prognostic factor for a long-term graft survival.

Membrane-anchored heparin-binding epidermal growth factor-like growth factor acts as a tumor survival factor in a hepatoma cell line

Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), which belongs to the EGF family, is produced as a membrane-anchored form (pro-HB-EGF) and later processed to a soluble form (sHB-EGF). It is known that high expression of pro-HB-EGF occurs in hepatoma tissues, although its biological meaning remains unknown. We established two types of hepatoma cell lines (AH66tc), which stably produce pro-HB-EGF and sHB-EGF, respectively. While sHB-EGF-producing cells (sHB-AH) showed rapid growth, pro-HB-EGF-producing cells (pHB-AH) showed markedly suppressed cell growth as compared with the parental cells. Transforming growth factor beta or serum-starved conditions induced apoptosis of mock and sHB-AH as well as the parental cells, but not of pHB-AH. The resistance to apoptosis upon serum-starved treatment was correlated with an increase in the rate of the G1 phase in the cell cycle due to up-regulation of the cyclin-dependent kinase inhibitor p21. The mechanism underlying this resistance of pHB-AH to apoptosis was thought to be related to the prolonged half-life of the EGF receptor followed by continuous phosphorylation of the tyrosine residues. These observations demonstrate a unique function of pro-HB-EGF that is not observed for the mature form and show that pro-HB-EGF may act as a tumor survival factor in hepatoma cells.

Arrest in primitive erythroid cell development caused by promoter-specific disruption of the GATA-1 gene

To elucidate the in vivo function of GATA-1 during hematopoiesis, we specifically disrupted the erythroid promoter of the GATA-1 gene in embryonic stem cells and generated germ line chimeras. Male offspring of chimeras bearing the targeted mutation were found to die by 12.5 days post coitus due to severe anemia while heterozygous females displayed characteristics ranging from severe anemia to normal erythropoiesis. When female heterozygotes were crossed with transgenic males carrying a reporter gene, which specifically marks primitive erythroid progenitors, massive accumulation of undifferentiated erythroid cells were observed in the yolk sacs of the GATA-1-mutant embryos, demonstrating that GATA-1 is required for the terminal differentiation of primitive erythroid cells in vivo.

Evaluation of peri-infarcted hypoperfusion with T2*-weighted dynamic MRI

The purpose of this study was to evaluate cerebral perfusion with T2*-weighted dynamic MRI in the area around the infarcted core. We examined seven patients with subacute cerebral infarction. After bolus injection a gadopentetate dimeglumine, a series of gradient-echo images were recorded in a selected slice. From these images, concentration-time curves were created on a region-of-interest (ROI) basis around infarction for calculating relative regional cerebral blood volume (rrCBV). Brain perfusion single photon emission computed tomography (SPECT) study also was performed with intravenous injection of 123I-labeled N-isopropyl-p-iodoamphetamine (123I-IMP). All patients showed prolonged signal decrease in the area around the infarcted core. ROI analysis showed significantly increased rrCBV compared to the normal side (P < .01, paired t test). The 123I-IMP SPECT study showed that these areas had decreased cerebral blood flow. Theses findings suggest compensatory vascular dilatation due to decreased perfusion pressure. T2*-weighted dynamic MRI is a useful method for detecting compensatory vasodilatation of ischemic insult in the peri-infarcted area.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 1st communication: antihypertensive effects of valsartan in hypertensive models

The antihypertensive effects of valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl¿ valine, CAS 137862-53-4, CGP 48933), an angiotensin II type 1 receptor antagonist, were examined in hypertensive rats and dogs. In normotensive rats and deoxycorticosterone acetate (DOCA)/salt hypertensive rats, valsartan had no effect on blood pressure. Single oral administrations of valsartan at doses of 3-30 mg/kg reduced blood pressure dose-dependently in renal (2 kidney 1 clip, 2K1C) hypertensive and spontaneously hypertensive rats (SHR). Repeated oral administrations of valsartan to these hypertensive rats controlled blood pressure throughout a treatment period of 4 weeks, and showed no rebound phenomenon following drug withdrawal. This drug at 30 mg/kg p.o. decreased blood pressure in renal (2K1C) hypertensive dogs by single and repeated administrations. The extent and duration of the hypotensive action of valsartan were similar to those of enalapril. Valsartan would thus appear as useful as enalapril.