Biomedical subjects

K Itoh

Publications and source records attributed to K Itoh.

At least 541 records · Page 30Linked to original sources

PubMed1997

Neuropeptide Y as a stimulator of Na+ -dependent Ca2+ efflux from freshly isolated adult rat cardiomyocytes.

Several physiological stimuli cause a rise in intracellular Ca2+ concentration ([Ca2+]i) in cardiomyocytes. This increased [Ca2+]i must be restored to physiological resting level to ensure response to further stimuli. In the present study, we examined the effect of neuropeptide Y (NPY), which is secreted from certain adrenergic or nonadrenergic neurons, on Ca2+ efflux from freshly isolated, quiescent adult rat cardiomyocytes. The isolated cardiomyocytes were preloaded with 45CaCl2 for 1 h. Then, the fractional release of 45Ca2+ from the cells was measured. NPY stimulated the efflux of 45Ca2+ from isolated adult rat cardiomyocytes in a concentration-dependent manner (10(-8) M to 10(-6) M). NPY (10(-6) M)-induced Ca2+ efflux was 2.0 +/- 0.16% of the total cellular content. The 45Ca2+ efflux from the cells was also stimulated by Y1 receptor agonist, [Leu31, Pro34]NPY, but not by Y2 receptor agonist, NPY13-36. The effect of NPY was inhibited by a peptide NPY inhibitor, NPY18-36 and a non-peptide NPY inhibitor, benextramine to a similar extent. From these results, it is conceivable that the effect of NPY on Ca2+ efflux from cardiomyocytes is mediated through Y1 receptors. It was also observed that NPY caused a rise in [Ca2+]i to almost 150 nM. NPY-stimulated 45Ca2+ efflux was not affected by removal of extracellular Ca2+, but was dependent on the presence of extracellular Na+. Moreover, NPY caused a 22Na+ influx into the cells of about 1.6-fold over the basal value which was inhibited by amiloride and 5-(N,N-dimethyl)-amiloride, known Na+/Ca2+ exchange inhibitors. In addition, isoproterenol also caused 45Ca2+ efflux from the cells and which was enhanced by the addition of NPY. These results suggest that NPY stimulates extracellular Na+-dependent 45Ca2+ efflux from freshly isolated adult rat cardiomyocytes, probably through its stimulatory effect on plasma membrane Y1 receptors with which NPY may couple during Na+/Ca2+ exchange.

Adenosine Triphosphatases↗

PubMed1997

Correlation between vitamin D receptor genotypes and bone mineral density in Japanese patients with osteoporosis.

In order to better understand the pathogenesis of osteoporosis, we investigated the correlation between the vitamin D receptor (VDR) genotypes defined by BsmI restriction enzyme, as well as other related factors, and the bone mineral density (BMD) at the lumbar spine in 90 Japanese patients with osteoporosis. The same study was performed in 36 patients with osteoarthrosis of the hip joint and 92 healthy volunteers. The majority of the VDR genotypes were bb, and a few of the population showed either the BB or Bb genotype in all three groups. There was no statistical difference in the frequencies of these VDR genotypes in the three groups. The mean age-matched value of BMD (Z scores) at the lumbar spine in patients with osteoporosis was significantly lower than that in patients with osteoarthrosis or healthy volunteers. The mean Z scores of the healthy volunteers with bb genotype were significantly higher than those with BB genotype, whereas those of the osteoporosis patients with BB genotype were significantly higher than those with Bb genotype. There was no significant difference in the mean Z scores between bb and Bb genotypes in patients with osteoporosis and healthy volunteers. No significant difference was seen in the mean Z scores in patients with osteoarthrosis regardless of genotype. On the other hand, body weight significantly correlated with BMD in patients with osteoporosis by simple- and multiple-regression analysis. These results indicate that the BMD at the lumbar spine in Japanese patients with osteoporosis is affected by body weight, and might be affected partially by the VDR genotypes defined by BsmI.

Adult↗

PubMed1997

Silencing of waxy genes in rice containing Wx transgenes.

In order to study gene silencing in a monocot system we introduced a waxy (Wx) gene into rice. In the pollen grain of the transgenic wild-type plants, two types of Wx gene silencing were observed: Type I in which all the pollen grains showed the mutant (wx) phenotype, and Type II in which 50% of the pollen grains showed the wx phenotype. Analysis of Wx gene expression in the progeny of selfing and outcrossing indicated that Wx gene silencing was meiotically transmitted to the offspring. The number of transgene copies and transgene loci was determined by Southern blot analysis and suggested that the Wx transgene may have a paramutagenic effect on the endogenous Wx genes. In contrast to the pollen grain, the wx phenotype was not observed in the endosperm. However, the level of WAXY (WX) protein in the endosperm of Type I lines was similar to that in non-transgenic seed, while in Type II lines two classes of seeds, showing high and low levels of the protein segregated. When the same transgene was introduced into wx mutants in which no Wx transcript was detectable, the transgene behaved as a dominant Mendelian factor and no silencing was found, suggesting that the activity of the endogenous Wx gene influences the silencing phenomenon. Our study of Wx gene silencing in rice extends the well-known phenomenon of gene silencing, so far observed mainly in dicots, to a cereal.

Gene Expression Regulation, Plant↗

PubMed1997

Lay-open pulmonary arterioplasty for postoperative hilar pulmonary artery stenosis.

OBJECTIVE: Lay-open pulmonary arterioplasty, a novel surgical technique to enlarge postoperative stenosis at the hilar pulmonary artery, was evaluated. METHODS: Lay-open arterioplasty, in which the enlarged hilar stenotic pulmonary artery is partially made up of previous surgical scar tissue instead of being covered by a patch, was performed on 10 patients whose ages ranged from 2.2 to 15.7 years. Surgical results were assessed by angiography. RESULTS: All patients tolerated the procedure without bleeding or embolic complications associated with pulmonary arterioplasty. Nine patients underwent concomitant procedures including total repair (n = 5), central interposing shunt (n = 3), and right ventricular outflow tract reconstruction (n = 1). No deaths or life-threatening events occurred during the total follow-up period of 18 patient-years. The stenotic segment was significantly enlarged from the preoperative diameter of 0.9 +/- 1.1 mm (mean +/- standard deviation) to the postoperative diameter of 8.0 +/- 1.3 mm, values which correspond to 7.0% +/- 8.8% and 68.4% +/- 11.5% of the normative values, respectively. A follow-up angiogram (n = 5) revealed an increase in the pulmonary artery diameter balanced with somatic growth (initial value, 65.2% +/- 9.0% of normal; second value, 69.1% +/- 7.7% of normal). No aneurysms or clinically significant restenoses were seen on the angiograms. CONCLUSIONS: Our initial midterm results with this method were promising. The pulmonary arteries subjected to this procedure grew in proportion to somatic growth.

Angioplasty↗

PubMed1997

Effect of docarpamine, a novel orally active dopamine prodrug, on the formation of free and sulfoconjugated dopamine in patients who underwent cardiac surgery.

To evaluate the clinical efficacy of orally active dopamine prodrug, docarpamine [N-(N-acetyl-L-methionyl)-O,O-bis (ethoxycarbonyl) dopamine], we examined its effect on the formation of free and sulfoconjugated dopamine in patients who underwent cardiac surgery. The preoperative values of free and sulfoconjugated dopamine in patients were 216 +/- 52 pg/ml and 4,930 +/- 820 pg/ml, respectively. The plasma level of free dopamine increased to 95.3 +/- 28.3 ng/ml by dopamine infusion after the operation and was sustained at a high level (87.7 +/- 26.5 ng/ml) by concomitant administration of docarpamine in spite of tapering of dopamine infusion. After stopping dopamine infusion, plasma level of free dopamine was 24.5 +/- 17.6 ng/ml maintained by oral administration of docarpamine alone. From these results, docarpamine may be a useful alternative to intravenous dopamine after cardiac surgery. Sulfoconjugated dopamine in plasma increased to 267 +/- 120 ng/ml after the start of dopamine infusion and increased further after oral docarpamine administration to 2,060 +/- 610 ng/ml. Since sulfoconjugated dopamine is thought to be a possible precursor of active free dopamine in plasma, orally administered docarpamine might be stored as a reserve pool for free dopamine in patients who undergo cardiac surgery.

Administration, Oral↗

PubMed1997

Effects of polyvalent alcohol solutions as dentine primers.

OBJECTIVES: The purpose of this study was to examine the bonding effect of polyvalent alcohols as dentine primers without a methacrylate group, which may cause contact dermatitis. METHODS: The efficacy of polyvalent alcohols as dentine primers was estimated by measuring the wall-to-wall polymerization contraction gap width of a light-activated resin composite filled in a cylindrical dentine cavity in an extracted human tooth. A dentine cavity was cleaned with ethylenediaminetetraacetic acid (EDTA) and primed with an aqueous solution of either ethylene glycol, glycerol, erythritol, xylitol or sorbitol at concentrations of between 25 and 75 wt%. A light-cured resin composite was filled after the application of a commercial dual-cured bonding agent. RESULTS: Contraction gap formation was completely prevented only in the group in which the dentine cavity had been primed with an aqueous solution of 62.5% wt% ethylene glycol. Furthermore, in the measurement of a tensile bond strength to a flat dentine surface, high tensile bond strength (17.5 +/- 4.4 MPa) was observed in the group that was primed with 62.5% ethylene glycol solution. CONCLUSION: These results suggest that it is not necessary to dissolve methacrylates in a dentine primer when the primer is dried with a blast of compressed air before application of a polymerizable, suitable bonding agent. It is concluded that a dentine primer composed of polyvalent alcohol solutions without a methacrylate group which may cause contact dermatitis, is effective as a dentine primer, affects the dentine surface, and promotes the efficacy of the dentine bonding system.

Acid Etching, Dental↗

PubMed1997

Screening and detection of gene mutations in Japanese patients with Fabry disease by non-radioactive single-stranded conformation polymorphism analysis.

We have applied non-radioactive polymerase chain reaction (PCR)-single-stranded conformation polymorphism (SSCP) to the detection of gene mutations causing Fabry disease. Nineteen of 22 known mutations were detected as electrophoretic mobility shifts on PCR-SSCP analysis. Then, DNA from newly diagnosed Japanese patients with the classical form of Fabry disease was subjected to PCR-SSCP analysis, and 4 novel mutations (1 small deletion, 1 nonsense mutation and 2 missense mutations) and 1 neutral polymorphism were identified. Furthermore, identification of an asymptomatic heterozygote and a hemizygote with moderate clinical manifestations was successfully achieved by application of this method to a family with the variant form of Fabry disease. PCR-SSCP is useful for the gene diagnosis of etiologically heterogeneous Fabry disease.

Adolescent↗

PubMed1997

Molecular form and subcellular distribution of acid beta-galactosidase in fibroblasts from patients with GM1 gangliosidosis, Morquio B disease and galactosialidosis.

The molecular form and subcellular distribution of acid beta-galactosidase in cultured fibroblasts from patients with beta-galactosidase deficiency (GM1-gangliosidosis, Morquio B disease and galactosialidosis) were studied, using antibodies against three different forms of the human enzyme: a high-molecular-weight multienzymic complex, a recombinant 84-kDa precursor, and a 64-kDa tryptic product of the precursor. The mature enzyme from normal fibroblasts was immunoprecipitated by the anti-complex and anti-64-kDa protein antibodies, but not by the anti-84-kDa precursor one. immunofluorescence staining of normal fibroblasts revealed the granular (lysosomal) distribution with anti-64-kDa protein antibody and the perinuclear reticular distribution with anti-84-kDa precursor antibody, probably representing the Golgi apparatus. Both patterns were demonstrated in Morquio B disease, but the residual enzyme activity was exclusively due to the mature enzyme. In Type 1 galactosialidosis, most of the expressed enzyme was detected as the precursor form with a perinuclear reticular distribution. In type 2 galactosialidosis, more than half of the enzyme activity was due to the mature form with a lysosomal distribution. Fibroblasts from a patient with GM1 gangliosidosis, expressing no beta-galactosidase mRNA, did not react against either anti-64-kDa protein antibody or anti-84-kDa precursor antibody. The combined use of immunoprecipitation and immunostaining was useful for analysing the pathophysiology of the intracellular processing and transport of the mutant beta-galactosidase.

Antibody Specificity↗

PubMed1997

Graded amounts of Xenopus dishevelled specify discrete anteroposterior cell fates in prospective ectoderm.

Signals emitted from the prospective dorsal marginal zone (the organizer) are thought to specify neuroectodermal cell fates along the anteroposterior (AP) axis, but the mechanisms underlying this signaling event remain to be elucidated. To assess the effect of Xenopus Dishevelled (Xdsh), a proposed component of the Wnt, Notch and Frizzled signal transduction pathways, on AP axis determination, it was supplied in varying doses to presumptive ectodermal cells. Two-fold increments in levels of microinjected Xdsh mRNA revealed a gradual shift in cell fates along the AP axis. Lower doses of Xdsh mRNA activated anterior neuroectodermal markers, XAG1 and Xotx2, whereas the higher doses induced more posterior neural tissue markers such as En2, Krox20 and HoxB9. At the highest dose of Xdsh mRNA, explants contained maximal amount of HoxB9 transcripts and developed notochord and somites. When compared with Xdsh, Xwnt8 mRNA also activated anterior neuroectodermal markers, but failed to elicit mesoderm formation. Analysis of explants overexpressing Xdsh at the gastrula stage revealed activation of several organizer-specific genes which have been implicated in determination of neural tissue (Xotx2, noggin, chordin and follistatin). Whereas Goosecoid, Xlim1 and Xwnt8 were not induced in these explants, another early marginal zone marker, Xbra, was activated at the highest level of Xdsh mRNA. These observations suggest that the effects of Xdsh on AP axis specification may be mediated by combinatorial action of several early patterning genes. Increasing levels of Xdsh mRNA activate posterior markers, whereas increasing amounts of the organizer stimulate the extent of anterior development (Stewart, R.M. and Gerhart, J.C. (1990) Development 109, 363-372). These findings argue against induction of the entire organizer by Xdsh in ectodermal cells and implicate signal transduction pathways involving Xdsh in AP axis determination. Thus, different levels of a single molecule, Xdsh, can specify distinct cell states along the AP axis.

Actins↗

PubMed1997

Processing down the garden path in Japanese: processing of sentences with lexical homonyms.

This paper investigates whether or not Japanese sentences with lexical homonyms cause measurable processing difficulties for Japanese speakers. Pairs of sentences involving lexical homonyms were tested with three types of questionnaires (who-did-what questions, difficulty ratings, and misleadingness ratings) and two experimental tests (an eye-movement monitoring experiment and a self-paced reading experiment). In both the difficulty rating and the misleadingness rating questionnaires, "late boundary" sentences, in which a phrase boundary followed a homonymous phrase, were rated as significantly more difficult and more misleading than "early boundary" sentences, where the boundary preceded the homonymous phrase. The results from the eye-movement study and the self-paced reading study showed that the late boundary difficulties were associated with the processing of the regions that followed the homonymous phrases. These results confirmed our prediction that the difficulty of late boundary sentences is likely to be caused by a subject's original misanalysis and subsequent revision. The results are discussed in terms of possible reasons why the early boundary version was preferred in these sentences.

Eye Movements↗

PubMed1997

Patients in phase I trials of anti-cancer agents in Japan: motivation, comprehension and expectations.

We attempted to characterize the motivation, comprehension and expectations of patients who had given informed consent to participate in phase I trials of anti-cancer agents at the National Cancer Center of Japan. Thirty-three patients were given a simple multiple-choice questionnaire and asked to return it at a later date. The completed survey was returned by 32 patients. The patients were surveyed before they had received any investigational phase I agents. Nineteen per cent of patients were motivated to participate in the phase I trials by the possibility of therapeutic benefit, 9% because participation seemed a better choice than no treatment and only 6% for altruistic reasons. Most patients comprehended the major features of a phase I trial, namely its investigational nature, the unknown effects of the agent investigated and the unclear benefit to the patients themselves. Fifty-nine per cent of the patients anticipated that they might suffer severe or life-threatening side-effects if they participated in the phase I trial, and 43% were able to indicate accurately the purpose of the phase I trial as a dose determination study. Although only a minority of the patients indicated that their motivation to participate was possible treatment benefit to themselves, when answering questions regarding expectations, more than half indicated that there might be personal benefits of varying degrees by participation.

Antineoplastic Agents↗

PubMed1997

Selective production of transgenic mice using green fluorescent protein as a marker.

The low efficiency of transgenic animal production by microinjection has been a serious problem especially for the production of transgenic livestock. We developed a method to selectively produce transgenic mice using green fluorescent protein (GFP) as a marker. Using this method, we obtained eight fetuses and four live-born mice derived from 55 GFP-positive blastocysts. PCR analysis showed 11 out of 12 mice (fetuses and newborn mice) were transgenic. Southern blot analysis showed that 8 out of 12 were transgenic. GFP expression was also observed in bovine blastocysts, suggesting that this method should contribute to the efficient production of transgenic livestock.

Animals↗

PubMed1997

The role of soluble growth factors in inducing transient growth and clonal extinction of stroma cell dependent erythroblastic leukemia cells.

A coculture system of a murine erythroblastic leukemia cell line (ELM-D) with its supportive stromal cell line (MS-5) was established. Long-term growth of ELM-D cells is strictly stroma cell dependent. Interaction between stem cell factor (SCF) and its receptor, c-kit, was demonstrated to be important for stroma cell-dependent growth by anti c-kit neutralizing monoclonal antibody (mAb) inhibition experiments. Significantly, soluble growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) or SCF of MS-5 stromal cells (MS-5 CM) could replace the requirement of stroma cells for a considerable period. However, ELM-D cells maintained in these growth factors underwent clonal extinction after 3-6 weeks unless contact with stroma was re-established. Furthermore, IL-3 or GM-CSF acted in a dominant manner in inducing cell death in the presence of stroma cells. Cells showing clonal extinction undergo programmed cell death and do not differentiate. These altered growth properties of ELM-D cells exposed to soluble growth factors or to stroma cells appear to be analogous to those described for T or B cells primed by antigen presenting cells and then grown in growth factors.

Animals↗

PubMed1997

Magnetic resonance imaging patterns in patients with multiple myeloma.

Sixty-one consecutive patients with multiple myeloma were studied with magnetic resonance (MR) imaging of the spine. Sagittal T1-weighted and short inversion time (TI) inversion recovery (STIR) images were obtained. The MR patterns of the bone marrow were classified as diffuse (D) (n=26), nodular (N) (n=11), D+N (n=13) or normal (n) (n=11). Abnormal patterns were seen in 50 (82%) of the 61 patients. Correlations were found between the MR imaging patterns and some laboratory findings (WBC, haematocrit, platelet count, serum albumin, and percentage of marrow plasmacytosis). The survival of the patients with abnormal MRI patterns was significantly poorer than that of the patients with normal patterns. However, the survival of patients with a nodular pattern did not differ from those with a normal pattern. The MR imaging pattern of the bone marrow in patients with multiple myeloma is a useful factor in the assessment of prognosis.

Adult↗

PubMed1997

Non-restricted T cell receptor (TCR)-V alpha and -V beta gene usage in patients with pulmonary sarcoidosis.

Sarcoidosis is a systemic granulomatous disease of unknown etiology characterized by the pronounced accumulation of CD4+ T cells and macrophages in the affected organs. TCR variable (V) alpha and V beta gene usage in patients with sarcoidosis is still a matter of discussion. In this investigation, we analysed TCR-V alpha and -V beta gene usage in bronchoalveolar lavage fluid (BALF) and peripheral blood mononuclear cells (PBMC) of 30 patients with active pulmonary sarcoidosis using an adapter ligation method, reverse transcriptase-polymerase chain reaction (RT-PCR), and sequence-specific oligonucleotide probe (SSOP) analyses. There was no significant difference in TCR-V alpha or -V beta gene usage between BALF (n = 12) or PBMC (n = 27) of patients and PBMC of healthy subjects (n = 10). Neither selective TCR-V alpha nor -V beta expansion was observed in the paired BALF and PBMC from seven of nine patients. However, selective expansions were observed in a few TCR-V alpha or -V beta subsets in the BALF or PBMC of some individuals. Although a modest increase in a few TCR-V alpha or -V beta subsets was observed in the BALF or PBMC of some individuals, the increased TCR-V alpha or -V beta subsets were not closely associated with the HLA-DRB1, DQA1, DQB1, and DPB1 alleles of these patients. These results suggest that TCR-V alpha or -V beta gene usage is not restricted in both lung and peripheral blood in the majority of patients with active pulmonary sarcoidosis.

Adult↗

PubMed1997

Infection with hepatitis G virus and its strain variant, the GB agent (GBV-C), among blood donors in Japan.

BACKGROUND: The purpose of the study was to survey the epidemiology of recently reported non-A through -E hepatitis virus designated hepatitis G virus (HGV) and its strain variant, the GB agent (GBV-C). STUDY DESIGN AND METHODS: Pilot samples from 2461 blood donors in Japan, randomly selected to form cohorts with different levels of alanine aminotransferase (ALT) and markers of hepatitis B virus or hepatitis C virus (HCV) infection, were tested for RNA of HGV/GBV-C by reverse transcription-polymerase chain reaction with nested primers deduced from the 5'-noncoding region. RESULTS: HGV/GBV-C RNA was detected in 23 (7.4%) of the 361 donors with anti-HCV and HCV RNA. This detection is more frequent than that in donors without elevated ALT levels (< or = 45 U/L) or markers of HCV or hepatitis B virus infection (15/1303; 1.2%) (p < 0.001), donors with ALT values between 46 and 99 U per L (0/108) (p < 0.002), donors with ALT values > or = 100 U per L (5/361; 1.4%), and donors with anti-HCV but without detectable HCV RNA (1/93; 1.1%) (p < 0.05). CONCLUSION: More than 1 percent of Japanese blood donors were infected with HGV/GBV-C, and the prevalence was much higher in those with HCV RNA. Should persistent infection with HGV/GBV-C induce any hepatotoxic sequelae, either alone or in concert with the other hepatitis viruses, screening of blood units for HGV/GBV-C would deserve consideration.

Adult↗

PubMed1997

The effects of high oral magnesium supplementation on blood pressure, serum lipids and related variables in apparently healthy Japanese subjects.

In a double-blind, placebo-controlled study, thirty-three subjects were allocated to undergo either a 4-week treatment with oral Mg supplementation (Mg(OH)2; 411-548 mg Mg/d) or a placebo. The urinary excretion of Mg increased significantly in both the first 2 weeks and the following 2 weeks of Mg supplementation, while the urinary Na excretion also increased significantly over the experimental period. The systolic and diastolic blood pressure values decreased significantly in the Mg group, but not in the placebo group. The urinary aldosterone excretion and packed cell volume increased significantly during the last 2 weeks of the experimental period compared with the run-in period and first 2 weeks of supplementation. There was a statistically significant positive correlation between the values for urinary noradrenaline excretion and diastolic blood pressure at the end of the supplementation period (both expressed as a percentage of the run-in value). Statistically significant increases in lecithin-cholesterol acyltransferase (EC 2.3.1.43; LCAT), HDL-cholesterol and apolipoprotein AI were also observed after Mg supplementation. A significant positive correlation was observed between the levels of LCAT and urinary Mg excretion for the experimental period (expressed as a percentage of the run-in value). The total cholesterol:HDL-cholesterol ratio decreased significantly during the last 2 weeks of Mg supplementation compared with the first 2 weeks and the run-in periods, but this did not occur in the placebo group. These results suggest that Mg supplementation may lower blood pressure through the suppression of the adrenergic activity and possible natriuresis, while also improving the serum lipids through the activation of LCAT in human subjects.

Administration, Oral↗

PubMed1997

Morphological changes of intraparenchymal arterioles after experimental subarachnoid hemorrhage in dogs.

OBJECTIVE: Morphological and microcirculatory changes in intraparenchymal vessels after subarachnoid hemorrhage (SAH) have not yet been fully clarified. We conducted this experimental study to investigate the serial morphological changes of intraparenchymal arterioles after SAH. METHODS: SAH was produced by injecting autologous arterial blood into the cisterna magna twice at 48-hour intervals in 30 dogs. The dogs were killed 3, 7, or 14 days after SAH, and then perfusion-fixed specimens of both anterior sylvian giri were obtained by using two methods. Microvascular corrosion casts produced by arterial injection of polyester resin were examined using scanning electron microscopy, and the widths of 40 arterioles of each animal were measured. Sectioned slices from the brain surface to 500 microns deep were examined by light microscopy, and external diameter, internal diameters, and wall thickness of the arterioles at depths of 50, 200, and 500 microns from the brain surface were morphometrically evaluated in 40 arterioles of each animal. In control animals receiving cisternal injections of mock cerebrospinal fluid (n = 10) and in healthy control animals (n = 10), the same examination and evaluation were performed. RESULTS: Corrosion casts of arterioles showed tapered narrowing with folding after SAH, and the width of the arterioles significantly decreased 3 and 7 days after SAH (P < 0.01). Morphometric examination by light microscopy showed a significant decrease of internal diameter of arterioles associated with a significant increase of wall thickness at any depth from the brain surface 3 and 7 days after SAH (P < 0.05 or P < 0.01). These findings improved 14 days after SAH. Control animals receiving cisternal injections of mock cerebrospinal fluid showed no significant differences compared with healthy control animals. CONCLUSION: These results suggest that constriction of intraparenchymal arterioles occurs after SAH and may contribute to delayed cerebral ischemia.

Animals↗