Clinical Significance of the Champagne Bottle Neck Sign in the Extracranial Carotid Arteries of Patients with Moyamoya Disease.

BACKGROUND AND PURPOSE: The champagne bottle neck sign represents a rapid reduction in the extracranial ICA diameters and is a characteristic feature of Moyamoya disease. However, the clinical significance of the champagne bottle neck sign is unclear. We investigated the relationship between the champagne bottle neck sign and the clinical and hemodynamic stages of Moyamoya disease. MATERIALS AND METHODS: We analyzed 14 patients with Moyamoya disease before revascularization (5 men, 9 women; age, 43.2 ± 19.3 years). The ratio of the extracranial ICA and common carotid artery diameters was determined using carotid ultrasonography or cerebral angiography; a ratio of < 0.5 was considered champagne bottle neck sign-positive. The clinical disease stage was determined using the Suzuki angiographic grading system. CBF and cerebral vasoreactivity also were measured. RESULTS: The ICA/common carotid artery ratio (expressed as median [interquartile range]) decreased as the clinical stage advanced (stages I-II, 0.71 [0.60-0.77]; stages III-IV, 0.49 [0.45-0.57]; stages V-VI, 0.38 [0.34-0.47]; P < .001). Lower ICA/common carotid artery ratio tended to occur in symptomatic versus asymptomatic arteries (0.47 [0.40-0.53] versus 0.57 [0.40-0.66], respectively; P = .06). Although the ICA/common carotid artery ratio was not related to cerebral perfusion, it decreased as cerebral vasoreactivity decreased (P < .01). All champagne bottle neck sign-positive arteries were classified as Suzuki stage ≥III, 73% were symptomatic, and 89% exhibited reduced cerebral vasoreactivity. In contrast, all champagne bottle neck sign-negative arteries were Suzuki stage ≤III, 67% were asymptomatic, and all showed preserved cerebral vasoreactivity. CONCLUSIONS: The champagne bottle neck sign was related to advanced clinical stage, clinical symptoms, and impaired cerebral vasoreactivity. Thus, detection of the champagne bottle neck sign might be useful in determining the clinical and hemodynamic stages of Moyamoya disease.

Galectin-7 in the stratum corneum: a biomarker of the skin barrier function.

OBJECTIVE: Skin barrier disruption often occurs in diseased and damaged skin conditions such as atopic dermatitis (AD). We focused the galectin-7 protein (Gal-7) as a biomarker of skin condition and assessed whether the content of Gal-7 in stratum corneum (scGal-7) could be used as an indicator of skin barrier disruption and as an index of local skin symptoms in AD patients. METHODS: Alteration of Gal-7 expression levels in keratinocyte and scGal-7 contents after barrier disruption by sodium dodecyl sulphate were evaluated in vitro and in vivo, respectively. Correlation between scGal-7 content and transepidermal water loss (TEWL) was examined in 126 healthy subjects. We performed single measurements of scGal-7 contents in 34 AD patients and serial measurements of 15 inpatients among them. SC samples were collected by the tape-stripping method, and scGal-7 content was determined using enzyme-linked immunosorbent assay. RESULTS: Gal-7 expression in keratinocytes increased after barrier disruption. The scGal-7 content reflected the disruption of the skin barrier. The scGal-7 contents and TEWL values correlated in healthy subjects. The scGal-7 level was higher in AD patients than in healthy subjects. The scGal-7 contents in the cheek and neck of AD patients significantly correlated with the total and local skin lesion severity scores. Serial measurements in the inpatients showed that the scGal-7 contents in the cheek and neck decreased in tandem with local severity scores in response to treatment. CONCLUSION: Measurement of scGal-7 content in tape-stripped samples was useful for the evaluation of the skin barrier function in dry skin conditions such as AD.

The human ether-a-go-go-related gene (hERG) current inhibition selectively prolongs action potential of midmyocardial cells to augment transmural dispersion.

The majority of drug induced arrhythmias are related to the prolongation of action potential duration following inhibition of rapidly activating delayed rectifier potassium current (I(Kr)) mediated by the hERG channel. However, for arrhythmias to develop and be sustained, not only the prolongation of action potential duration but also its transmural dispersion are required. Herein, we evaluated the effect of hERG inhibition on transmural dispersion of action potential duration using the action potential clamp technique that combined an in silico myocyte model with the actual I(Kr) measurement. Whole cell I(Kr) current was measured in Chinese hamster ovary cells stably expressing the hERG channel. The measured current was coupled with models of ventricular endocardial, M-, and epicardial cells to calculate the action potentials. Action potentials were evaluated under control condition and in the presence of 1, 10, or 100 µM disopyramide, an hERG inhibitor. Disopyramide dose-dependently increased the action potential durations of the three cell types. However, action potential duration of M-cells increased disproportionately at higher doses, and was significantly different from that of epicardial and endocardial cells (dispersion of repolarization). By contrast, the effects of disopyramide on peak I(Kr) and instantaneous current-voltage relation were similar in all cell types. Simulation study suggested that the reduced repolarization reserve of M-cell with smaller amount of slowly activating delayed rectifier potassium current levels off at longer action potential duration to make such differences. The action potential clamp technique is useful for studying the mechanism of arrhythmogenesis by hERG inhibition through the transmural dispersion of repolarization.

MR imaging texture analysis of the corpus callosum and thalamus in amnestic mild cognitive impairment and mild Alzheimer disease.

BACKGROUND AND PURPOSE: TA is a branch of image processing that seeks to reduce image information by extracting texture descriptors from the image. TA of MR images of anatomic structures in mild AD and aMCI is not well-studied. Our objective was to attempt to find differences among patients with aMCI and mild AD and normal-aging subjects, by using TA applied to the MR images of the CC and the thalami of these groups of subjects. MATERIALS AND METHODS: TA was applied to the MR images of 17 patients with aMCI, 16 patients with mild AD, and 16 normal-aging subjects. The TA approach was based on the GLCM. MR images were T1-weighted and were obtained in the sagittal and axial planes. The CC and thalami were manually segmented for each subject, and 44 texture parameters were computed for each of these structures. RESULTS: TA parameters showed differences among the 3 groups for the CC and thalamus. A pair-wise comparison among groups showed differences for AD-control and aMCI-AD for the CC; and for AD-control, aMCI-AD, and aMCI-control for the thalamus. CONCLUSIONS: TA is a useful technique to aid in the detection of tissue alterations in MR images of mild AD and aMCI and has the potential to become a helpful tool in the diagnosis and understanding of these pathologies.

Antiepileptic drug response in temporal lobe epilepsy: a clinical and MRI morphometry study.

OBJECTIVE: To investigate the relationship between brain MRI and clinical characteristics and patterns of antiepileptic drug (AED) response in patients with mesial temporal lobe epilepsy (MTLE). METHODS: A total of 165 MTLE patients were divided into seizure-free with AED (AED responders, n = 50), pharmacoresistant (n = 87), and remitting-relapsing seizure control group (n = 28). All groups were evaluated regarding age, frequency of seizures, and age at epilepsy onset, duration of epilepsy, febrile seizures, presence and side of hippocampal atrophy (HA), and initial precipitating injuries. For gray matter (GM) MRI voxel-based morphometry (VBM) we selected only patients with unilateral HA on visual MRI analysis (n = 100). Comparisons were made between all groups and 75 healthy controls. RESULTS: Age at epilepsy onset was lower (p = 0.005) and initial frequency of seizures was higher in the pharmacoresistant compared with the other 2 groups (p = 0.018). All groups showed GM atrophy compared to controls in ipsilateral hippocampus, bilateral parahippocampal gyri, frontal, occipital, parietal, and cerebellar areas. In the AED responders group, such findings were more restricted to areas ipsilateral to the epileptic focus and more widespread in the pharmacoresistant and remitting-relapsing groups. VBM pairwise comparisons showed areas with GM volume reduction in the pharmacoresistant and remitting-relapsing groups compared with AED responders in bilateral periorbital frontal (p < 0.01), cingulum (p < 0.05), and temporal lobe contralateral to the epileptic focus (p < 0.05). CONCLUSIONS: Pharmacoresistant and remitting-relapsing groups presented a similar pattern of GM atrophy, which was more widespread compared with AED responders. Conversely, age at epilepsy onset was lower and initial seizure frequency was higher in pharmacoresistant patients.

Rolandic discharges: clinico-neurophysiological correlation.

OBJECTIVE: The aim of this study was to analyze neurophysiologic aspects of rolandic discharges. METHODS: We reviewed 45 electroencephalograms of patients divided into two groups: those with benign childhood epilepsy with centrotemporal spikes (BCECTS) and symptomatic partial epilepsy (SPE), following ILAE criteria (1989). The EEG data analyzed were: horizontal dipole discharges, double spike phenomenon, the extension of epileptiform discharges and background activity. RESULTS: There was a predominance of horizontal dipole between patients with BCECTS compared with patients with SPE; however, this difference was not statistically significant. There was also no statistically significant difference between the two groups when the double spike phenomenon and the extension of discharges beyond the rolandic area were considered. The slower background activity in the SPE group was the only variable with statistical significance. CONCLUSIONS: This study revealed similarities between rolandic discharges of two different epilepsy groups. The only reliable parameter to differentiate the groups was the background activity. SIGNIFICANCE: Our findings suggest that most EEG rolandic features are not pathognomonic of BCECTS, as they are related to the area of the discharges and not to the epileptic syndrome itself.

Relationship between environmental factors and gray matter atrophy in refractory MTLE.

OBJECTIVE: To investigate clinical, neuropsychological, and MRI abnormalities (gray matter atrophy [GMA] and white matter atrophy [WMA]) in surgical mesial temporal lobe epilepsy (MTLE) patients with and without familial antecedent for epilepsy. METHODS: A cohort study including 69 operated patients with unilateral MTLE, divided into a group of 29 patients (mean age 35.8 +/- 10.4 years) with a negative family history (FH) of epilepsy and a group of 40 patients (32.8 +/- 10 years) with a positive FH. We performed voxel-based morphometry (VBM) on preoperative MRIs and investigated possible clinical and neuropsychological differences between the 2 groups. We also performed VBM and t tests to compare the patients' groups with normal controls. RESULTS: The negative-FH group had lower IQ scores (p = 0.004), performed poorer on the Boston Naming Test (p = 0.02) and on delayed recall (p = 0.03), and presented a more prominent asymmetry index of hippocampal volume (p = 0.04) and more frequent initial precipitating injuries (p = 0.023). VBM showed a more restricted pattern of GMA in the positive-FH group and a more bilateral and widespread pattern of GMA in the negative-FH group, involving thalami, temporal, frontal, parietal, and occipital lobes. WMA was widespread and bilateral in both groups. CONCLUSIONS: The more widespread structural voxel-based morphometry abnormalities and worse IQ performance identified in the negative-family history (FH) group may result from a stronger environmental influence, including initial precipitating injuries. This is further support for the hypothesis that hippocampal sclerosis in mesial temporal lobe epilepsy with positive FH is determined by a stronger genetic predisposition with less influence of environmental factors compared with patients in the negative-FH group.

Differences in grey and white matter atrophy in amnestic mild cognitive impairment and mild Alzheimer's disease.

BACKGROUND: Grey matter (GM) atrophy has been demonstrated in amnestic mild cognitive impairment (aMCI) and mild Alzheimer's disease (AD), but the role of white matter (WM) atrophy has not been well characterized. Despite these findings, the validity of aMCI concept as prodromal AD has been questioned. METHODS: We performed brain MRI with voxel-based morphometry analysis in 48 subjects, aiming to evaluate the patterns of GM and WM atrophy amongst mild AD, aMCI and age-matched normal controls. RESULTS: Amnestic mild cognitive impairment GM atrophy was similarly distributed but less intense than that of mild AD group, mainly in thalami and parahippocampal gyri. There were no difference between aMCI and controls concerning WM atrophy. In the mild AD group, we found WM atrophy in periventricular areas, corpus callosum and WM adjacent to associative cortices. DISCUSSION: We demonstrated that aMCI might be considered a valid concept to detect very early AD pathology, since we found a close proximity in the pattern of atrophy. Also, we showed the involvement of WM in mild AD, but not in aMCI, suggesting a combination of Wallerian degeneration and microvascular ischaemic disease as a plausible additional pathological mechanism for the discrimination between MCI and AD.

The effect of endostatin evaluated in an experimental animal model of collagen-induced arthritis.

OBJECTIVE: To investigate the arthritis-inhibiting effect of endostatin, a potent angiogenesis inhibitor, on type II collagen-induced arthritis (CIA). METHODS: In an experimental system of prophylactic administration, endostatin was administered once daily at 1 mg/kg/day or 10 mg/kg/day for 2 weeks from before the onset of arthritis. In the experimental system of therapeutic administration, mice with an arthritis score of 1 to 3 were administered endostatin once daily at 10 mg/kg. In the experimental system of continuous administration, endostatin was administered using an osmotic pump capable of continuously administering a calculated dose of 1 mg/kg/day for 2 weeks. RESULTS: Arthritis scores were lower in a dose-dependent manner in the prophylactic administration group than in the control group. Arthritis scores were lower in the therapeutic administration group than in the control group. Compared with the once-daily dosage regimen, the administration of endostatin by an osmotic pump achieved a similar arthritis-inhibiting effect at one-tenth of the dose. CONCLUSION: Both prophylactic and therapeutic administration of endostatin inhibited type II CIA in mice. The administration method using an osmotic pump is useful.

Néel temperature of quasi-low-dimensional Heisenberg antiferromagnets.

The Néel temperature T(N) of quasi-one- and quasi-two-dimensional antiferromagnetic Heisenberg models on a cubic lattice is calculated by Monte Carlo simulations as a function of interchain (interlayer) to intrachain (intralayer) coupling J(')/J down to J(')/J approximately = 10(-3). We find that T(N) obeys a modified random-phase approximationlike relation for small J(')/J with an effective universal renormalized coordination number, independent of the size of the spin. Empirical formulas describing T(N) for a wide range of J(') and useful for the analysis of experimental measurements are presented.

Quantitative nested reverse transcriptase PCR vs. real-time PCR for measuring AML1/ETO (MTG8) transcripts.

A quantitative nested reverse transcriptase polymerase chain reaction (QN-RT-PCR) method was developed using a plasmid cDNA containing the AML1/ETO (MTG8) fusion transcript from Kasumi-1 cells, an acute-myelogenous leukemia cell line with the t(8;21) translocation. In this method, the plasmid was detectable at a concentration of 10(-17) m. The fusion transcript in a mixture of 10(7) Rice94 (Burkitt lymphoma cell line) cells containing two Kasumi-1 cells was detectable at 10(-17) m. In a previously published real-time PCR method, the plasmid containing the fusion transcript was detectable at 10(-16) m or higher, and 20 or more Kasumi-1 cells were detectable in 10(7) Rice94 cells. Thus, this QN-RT-PCR method is more sensitive than the real-time PCR. When the same samples were examined by real-time PCR and our QN-RT-PCR method, in one patient in clinical remission after chemotherapy and allogeneic-bone marrow transplantation (BMT), the transcript was detected by QN-RT-PCR 60 days prior to hematological relapse, in contrast to 10 days before hematological relapse by real-time PCR. The transcript level was below 10(-17) m (undetectable) with this QN-RT-PCR in patients in clinical remission after chemotherapy and BMT, while it was 10(-15)-10(-16) m in patients in clinical remission after chemotherapy alone. The quantitative difference of the transcript level in minimal residual disease (MRD) between these two different types of clinical remission was estimated to be at least 10(2)-fold. This QN-RT-PCR method is useful for predicting hematological relapse and for quantitatively estimating MRD in different types of clinical remission.

Effect of surgical treatment on the cellular immune response of gastric cancer patients.

Patients with gastric cancer have a variety of immunological abnormalities. In the present study the lymphocytes and their subsets were determined in the peripheral blood of patients with gastric cancer (N = 41) both before and after surgical treatment. The percent of helper/inducer CD4 T cells (43.6 +/- 8.9) was not different after tumor resection (43.6 +/- 8.2). The percent of the cytotoxic CD8+ T cell population decreased significantly, whether patients were treated surgically (27.2 +/- 5.8%, N = 20) or not (27.3 +/- 7.3%, N = 20) compared to individuals with inflammatory disease (30.9 +/- 7.5%) or to healthy individuals (33.2 +/- 7.6%). The CD4/CD8 ratio consequently increased in the group of cancer patients. The peripheral blood lymphocytes of gastric cancer patients showed reduced responsiveness to mitogens. The defective blastogenic response of the lymphocytes was not associated with the production of transforming growth factor beta (TGF- ) since the patients with cancer had reduced production of TGF- Beta1 (269 +/- 239 pg/ml, N = 20) in comparison to the normal individuals (884 +/- 175 pg/ml, N = 20). These results indicate that the immune response of gastric cancer patients was not significantly modified by surgical treatment when evaluated four weeks after surgery and that the immunosuppression observed was not due to an increase in TGF- 1 production by peripheral leukocytes.

Effect of surgical treatment on the cellular immune response of gastric cancer patients

Patients with gastric cancer have a variety of immunological abnormalities. In the present study the lymphocytes and their subsets were determined in the peripheral blood of patients with gastric cancer (N = 41) both before and after surgical treatment. The percent of helper/inducer CD4 T cells (43.6 ± 8.9) was not different after tumor resection (43.6 ± 8.2). The percent of the cytotoxic CD8+ T cell population decreased significantly, whether patients were treated surgically (27.2 ± 5.8 percent, N = 20) or not (27.3 ± 7.3 percent, N = 20) compared to individuals with inflammatory disease (30.9 ± 7.5 percent) or to healthy individuals (33.2 ± 7.6 percent). The CD4/CD8 ratio consequently increased in the group of cancer patients. The peripheral blood lymphocytes of gastric cancer patients showed reduced responsiveness to mitogens. The defective blastogenic response of the lymphocytes was not associated with the production of transforming growth factor beta (TGF-á) since the patients with cancer had reduced production of TGF-á1 (269 ± 239 pg/ml, N = 20) in comparison to the normal individuals (884 ± 175 pg/ml, N = 20). These results indicate that the immune response of gastric cancer patients was not significantly modified by surgical treatment when evaluated four weeks after surgery and that the immunosuppression observed was not due to an increase in TGF-á1 production by peripheral leukocytes

Pattern of cytokine secretion by peripheral blood cells of patients with multiple sclerosis in Brazil.

Autoimmune T cells play a key role as regulators and effectors of organ-specific autoimmune disease. In multiple sclerosis (MS), activated T cells specific for myelin components produce a plethora of inflammatory cytokines and mediators that contribute to myelin damage. The production of proinflammatory and regulatory cytokines by peripheral blood cells from patients with active and stable MS and healthy controls were examined. The results show that TNF alpha production was somewhat elevated in active MS with no significant increase in the level IFN gamma, whereas in the chronic phase the anti-inflammatory cytokines IL-10 and TGF beta increased, accompanied by a reduction in IFN gamma when stimulated by myelin basic protein. Multiple Sclerosis (2000) 6 293 - 299

Reversible dissociation/association of D-amino acid transaminase subunits: properties of isolated active dimers and inactive monomers.

The crystal structure of dimeric D-amino acid transaminase shows that the two Trp-139 sites are located in a hydrophobic pocket at the interface between the subunits and that the two indole side chains face one another and are within 10 A of coenzyme. This enzyme prefers an aromatic character at position 139, as previously demonstrated by the finding that Phe-139 but no other substitution tested provides the maximum degree of thermostability and catalytic efficiency. Here we show that an equilibrium between active dimers and inactive monomers can be demonstrated with the W139F mutant enzyme, whereas with the wild-type enzyme the subunit interface is so tight that a study of this equilibrium is precluded. We show how the processes of dimerization of monomers and dissociation of dimers to monomers are controlled. Lower pH (5.0) favors monomer formation from dimers. Gel filtration and activity analysis show that at higher pH (7.0) the monomers combine to form active dimers with a K(d) of 0.17 microM. This assembly process is relatively slow and takes several hours for completion, thereby permitting accurate measurement of kinetics and equilibrium parameters. Absorption and circular dichroism spectra of dimers and monomers are significantly different, indicating that the environment around the cofactor is very likely altered between them. The circular dichroism peak of the W139F dimer at 418 nm is less negative than that of the wild-type enzyme in accordance with its lower visible absorbance; the circular dichroism peak of the W139F monomer at 418 nm is more negative than that of the wild-type enzyme. The dissociation of dimers to monomers has also been studied by taking advantage of these spectral differences, thus permitting the rates of the dissociation and the reassociation to be calculated and compared. 2-Mercaptoethanol assists in the conversion of monomers to dimers. The results here describe dissociation/reassociation in the dimeric enzyme under native conditions without denaturants.

Interferon beta modulates experimental autoimmune encephalomyelitis by altering the pattern of cytokine secretion.

The mechanism of action underlying the beneficial effect of IFNbeta in Multiple Sclerosis is poorly understood. Experimental Autoimmune Encephalomyelitis (EAE) is the experimental model for Multiple Sclerosis; therefore, we investigated the effects of recombinant mouse IFNbeta on the severity of EAE induced in SJL mice and on cytokine production by Th1 and Th2 lymphocytes. The results indicated that rmIFN beta reduced the disease activity with an I.P. dosage of 10,000 U/day every other day, and successfully treated EAE mice revealed reduced amounts of IFN gamma; no changes in the levels of IL4 were observed, although thera was a significant increase in IL10 and TGFbeta production. Beneficial effects on EAE are associated with inhibition of inflammatory cytokines and stimulation of anti-inflammatory cytokines.

Evidence for the presence of major peripheral myelin glycoprotein P0 in mammalian spinal cord and a change of its glycosylation state during aging.

Glycoproteins, which react with Lens culinaris agglutinin, in the membrane preparation of various portions of brains and spinal cords, obtained from 9-week-old rats and 29-month-old rats, were comparatively analyzed by SDS-polyacrylamide gel electrophoresis. In contrast to the samples from brain, which showed similar staining patterns in the two different age groups, the glycoprotein patterns of spinal cords showed marked differences by the age of donors. The most prominent evidence is that a glycoprotein with an apparent molecular weight of 30 kDa (gp30) was detected in the aged rats, but not in the young adult rats. Based on the amino acid sequence data around the glycosylation site, the gp30 was identified as P0, which is a member of immunoglobulin superfamily and a major structural component of mammalian peripheral nerve myelin. This is the first report indicating that P0, which has been considered as a peripheral nerve-specific glycoprotein, occurs also in the spinal cord of mammals. In addition, nonglycosylated P0 molecule could be detected in the spinal cord of young adult rats by anti-P0 polyclonal antibody. These results indicate that the glycosylation state of the P0 molecule in the spinal cord changes during aging.

Experimental studies on potentiation of the antitumor activity of 5-fluorouracil with 3'-azido-3'-deoxythymidine for the gastric cancer cell line MKN28 in vivo.

A new method of biochemical modulation of 5-fluorouracil (5-FU) with 3'-azido-3'-deoxythymidine (AZT) was studied experimentally. Nude mice transplanted with cells of the human gastric cancer cell line MKN28 were divided into 4 groups, i.e., control, 5-FU, AZT, and 5-FU plus AZT, and the antitumor activities were compared. Based on the assessment of tumor volume, significant suppression of tumor growth was observed in the 5-FU and 5-FU plus AZT groups (P<0.05, P<0.01, versus control, respectively). The thymidylate synthase (TS) inhibition rate, an index of inhibition of the de novo pathway, was significantly higher in the 5-FU and 5-FU plus AZT groups than in the control group (P<0.01), but it did not differ from the control in the AZT group. TS-bound FdUMP tended to be higher in the 5-FU plus AZT group than in the 5-FU group. The activity of thymidine kinase (TK) and the uptake ratio of 5-bromo-2'-deoxyuridine (BrdU), indices of salvage pathway activity, were significantly lower in the AZT and 5-FU plus AZT groups than in the control group (TK, P< 0.05, P < 0.01; uptake ratio of BrdU, P < 0.01, P < 0.05, respectively). There were slight losses of body weight in the 5-FU and 5-FU plus AZT groups compared with that in the control group, but no difference between the AZT and control groups in weight loss. These findings suggest that addition of AZT plays an important role in potentiating the antitumor activity of 5-FU through both blockage of a compensatory increase of activity in the salvage pathway and also an increase in TS-bound FdUMP, and has no adverse effects. Thus, the combination of 5-FU and AZT could be useful as a new modality in gastric cancer chemotherapy.

Insulin nonattenuation of vasoactive agent-induced responses in mesangial cells from spontaneously hypertensive rats.

We recently found that insulin attenuates intracellular calcium transients and cell contraction caused by vasoactive agents in cultured rat mesangial cells. Because altered glomerular function may be causally related to the evolution of hypertension, we examined in the present study the effects of insulin on the functions of mesangial cells derived from spontaneously hypertensive rats (SHR) of 4- and 8-weeks of age. Age-matched Wistar Kyoto rats (WKY) were used as controls. Intracellular calcium concentration ([Ca2+]i) was measured with Fura-2 method in suspended mesangial cells. Pretreatment of mesangial cells with 5 micrograms/ml insulin for 120 minutes did not affect basal [Ca2+]i in either WKY or SHR mesangial cells. However, insulin pretreatment significantly attenuated [Ca2+]i transients to vasoactive agents in WKY mesangial cells. In contrast, [Ca2+]i transients to these agents were not attenuated by insulin in SHR mesangial cells. Additionally, SHR mesangial cell contraction in response to angiotensin II (Ang II) was not altered by insulin, while WKY mesangial cell contraction to Ang II was, as in normal Wistar rats, significantly reduced by insulin. Since we previously showed the possibility that the attenuation of calcium signal by insulin is via insulin-like growth factor I (IGF-I) receptor, we also examined the effect of IGF-I. In contrast to WKY mesangial cells, IGF-I-induced attenuation of [Ca2+]i responses to platelet activating factor was absent in SHR mesangial cells. [125I]-IGF-I binding in SHR mesangial cells was not significantly different from that in WKY mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)