MEKA/phosducin attenuates hydrophobicity of transducin beta gamma subunits without binding to farnesyl moiety

Hydrophobic modifications of transducin (T) gamma, such as farnesyl-and carboxyl-methylation, are essential for the association of T beta gamma with the photoreceptor disc membrane, and MEKA/phosducin is known to inhibit the association. In this study, we examined the effect of MEKA on the hydrophobicity of T beta gamma. MEKA could bind to T beta gamma without farnesyl/carboxyl-methyl moieties as well as native T beta gamma. In the Triton X-114 phase separation assay, T beta gamma-MEKA complex was recovered in the aqueous phase, whereas T beta gamma was recover in the detergent phase. N-terminal portion of MEKA which includes T beta gamma-binding domain was not sufficient to reduce the hydrophobicity of T beta gamma or to dissociate T beta gamma from the membrane. The data suggest that MEKA attenuates the hydrophobicity of T beta gamma to result in the dissociation of T beta gamma from the membrane without directly binding to farnesyl/carboxyl-methyl moieties.

The possible role of nitric oxide in relaxations and excitatory neuroeffector transmission in the cat airway

1. To study the possible role of nitric oxide (NO free radical; NO) or NO-containing compounds in the non-adrenergic, non-cholinergic (NANC) relaxations, we observed the effects of carboxy-2-phenyl-4, 4, 5, 5-tetramethyl-imidazoline-1-oxyl-3-oxide (C-PTIO; a newly synthesized NO scavenger) on NANC relaxations in the cat airway. In addition, we also observed the effects of C-PTIO on excitatory junction potentials (EJPs), since NO has a prejunctional action on transmitter release. 2. Nitrosocystine (Cys-NO) (10(-7)-10(-3) M) dose-dependently relaxed the bronchial tissue in the presence of 5-HT, atropine and guanethidine and C-PTIO (10(-4) M) shifted the concentration-response curve of the Cys-NO to the right. 3. Electrical field stimulation (EFS) evoked biphasic NANC relaxations in the small bronchi of the cat. In general, C-PTIO suppressed non-selectively both the first and second components of the NANC relaxations to a similar extent. However, in some bronchial preparations C-PTIO (10(-4) M) selectively suppressed the first component of the NANC relaxation to approximately 50% of the initial value, enhancing the amplitude of the second component of the NANC relaxations. 4. After pretreatment of the bronchial tissues with alpha-chymotrypsin (1 unit ml-1) for 30 min in order to inhibit any response to peptides, EFS evoked monophasic NANC relaxation. C-PTIO (10(-5) - 10(-4) M) dose-dependently suppressed, and at a concentration of 10(-4) M almost halved, the amplitude of NANC relaxation. Additional application of L-NAME further reduced the C-PTIO-resistant NANC relaxation to 20-30% of the initial value. 5. C-PTIO (10(-4) M) enhanced the EJP amplitude evoked by single EFS in the trachea but not in the bronchi. However, C-PTIO enhanced the summation of the EJPs to repeated stimulation to a similar extent in the tracheal and bronchial tissues. Simultaneous application of C-PTIO and L-NAME did not further enhance the summation. 6. These results indicate that NO. and NO-containing compounds are involved in the L-NAME-sensitive NANC relaxation in the cat airway, and that only NO. has a prejunctional action which inhibits excitatory neuroeffector transmission.

Carnosine sustains the retention of cell morphology in continuous fibroblast culture subjected to nutritional insult

L- Carnosine (beta-alanyl L-histidine), occurring abundantly in skeletal muscles, has been suggested to possess antioxidant and anti-aging properties. Using three different experimental approaches (microscopic, flow cytometric and ELISA for one of the markers of DNA oxidative damage) this study on rat embryonic fibroblasts demonstrates that L-carnosine at 30 mM concentration sustains the retention of cell morphology even during a nutritional insult for five weeks. Also, L-carnosine significantly reduces the formation of 8-hydroxy deoxyguanosine (8-OH dG) in the cells after four weeks of continuous culture. Thus it could be inferred that the anti-senescent effect of L-carnosine is probably linked to its inhibition of formation of intracellular 8-OH dG during oxidative stress.

[Developmental changes in the pacemaker current and membrane currents of the guinea pig myocardium]

The pacemaker current (I(f)) in embryonic chick ventricular myocytes is present, but decreases during development. beta-Adrenergic agonists stimulate I(f), whereas muscarinic cholinergic agonists inhibit I(f) and reverse beta-adrenoceptor stimulation. G-proteins directly and indirectly couple autonomic receptors to I(f) channels in embryonic ventricular cells. The I(f) may contribute partly to the electrogenesis of the pacemaker potential. On the other hand, Ito current, voltage-dependent and 4-AP-sensitive, exists even in young embryonic cardiomyocytes, but not in all cells. The Ito increases during development, resulting in modulation of the action potential configuration. The action potential duration of guinea pig ventricular myocardium decreases during the late fetal period and increases postnatally. Single cell voltage clamp analyses revealed that the decrease and increase in action potential duration are due to developmental increases in the current densities of the calcium current and delayed rectifier potassium current, respectively. The role of the sarcoplasmic reticulum in contraction and relaxation of the guinea pig myocardium increases during fetal development.

Decrease in oxygen cost of contractility during hypocapnic alkalosis in canine hearts

Ca2+ sensitization of contractile machinery could theoretically enhance the mechanoenergetics of the heart. We studied the effects of alkalosis with Ca2+ sensitization on mechanoenergetics within the framework of the relationships of left ventricular pressure-volume area (PVA; a measure of the total mechanical energy), myocardial oxygen consumption per beat (VO2), and the contractility index [E(max) (slope of end-systolic pressure-volume relation)] in 10 excised, cross-circulated canine hearts. Alkalosis was stably maintained without hypoxia (mean pH 7.66). Alkalosis increased E(max) without changing the slope of the VO2-PVA relation, a reflected contractile efficiency. The incremental ratio of unloaded VO2 to E(max) in alkalosis was significantly lower than that in Ca2+ sensitization (0.0012 +/- 0.0010 vs. 0.0062 +/- 0.0030 ml O2 . mmHg-1 . ml . beat-1 . 100 g LV-2; P < 0.01). Basal metabolism under KCl arrest was unchanged by alkalosis, indicating the decreased energy cost of the excitation-contraction coupling by alkalosis. Compared with the control, alkalosis increased E(max) during the Ca2+ infusion of various concentrations without any further increase in unloaded VO2. Thus we demonstrated a decreased oxygen cost of contractility during alkalosis, presumably due to Ca2+ sensitization.

24R,25-dihydroxyvitamin D3 promotes bone formation without causing excessive resorption in hypophosphatemic mice

To clarify the differences in the action of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and 24,25-(OH)2D3 in hypophosphatemic (Hyp) mice, a model for familial X-linked hypophosphatemic rickets in humans, we carried out histomorphometric examinations of the effects of these agents in the lumbar vertebra of these mice. The Hyp mice received 1-1000 micrograms/kg.day 24,25-(OH)2D3, 0.01-0.1 micrograms/kg.day 1,25.(OH)2D3, or vehicle alone given daily for 28 days by ip injection. Histomorphometrically, 1,25-(OH)2D3 and 24,25-(OH)2D3 showed similar effects on bone formation. The parameters of bone formation, mineralized bone volume/bone volume, mineral apposition rate, and bone formation rate/bone surface, were improved to a similar extent in a dose-dependent manner by 1,25-(OH)2D3 and 24,25-(OH)2D3, but there were remarkable differences in the indexes of the bone resorption between these two metabolites. In 24,25-(OH)2D3-treated Hyp mice, osteoclast number/bone perimeter and osteoclast surface/bone surface, the parameters of bone resorption, increased to control levels and did not change according to the dose of 24,25-(OH)2D3. However, in 1,25-(OH)2D3-treated Hyp mice, these values increased remarkably, exceeding the control level. That is, 24,25-(OH)2D3 normalized bone resorption in the rachitic mice, whereas 1,25-(OH)2D3 caused excessive stimulation of bone resorption. This qualitative difference between the two compounds contributes to the superior effects exerted by 24,25-(OH)2D3 in improving the bone lesion in Hyp mice. At doses from 1-1000 micrograms/kg.day, 24,25-(OH)2D3 had dose-dependent effects in increasing bone formation without promoting excessive bone resorption, as shown by histomorphometric analysis.

The reference value of erythrocyte sedimentation rate for differential diagnosis of rheumatic fever among Bangladeshi children

The aim of the present study is to determine the reference value of erythrocyte sedimentation rate for differential diagnosis of rheumatic fever in the National Center for Control of Rheumatic Fever and Heart Diseases, Dhaka, Bangladesh among patients with signs and symptoms which may be related to acute rheumatic fever. All medical records for the patients aged 5 to 20 years who attended the outpatient department of the hospital between July, 1994 and November, 1995 were reviewed. Fifty-three of 337 such patients had acute rheumatic fever defined by the updated Jones criteria. The performance of erythrocyte sedimentation rate test was evaluated by sensitivity, specificity, positive predictive value, and receiver operating characteristic curve. The findings of this study suggest that the lower limit for a positive test should be considered at 30 mm (Westergren 1 h) in this hospital.

Role of mast cells, eosinophils and IL-5 in the development of airway hyperresponsiveness in sensitized mice

BACKGROUND AND OBJECTIVE

In order to study the role of mast cells and IL-5 in allergen-induced airway hyperreactivity in mice, airway responsiveness in WBB6F1-W/Wv mice (mast cell deficient) and the effects of anti-IL-5 monoclonal antibody (NC-17) and three anti-allergic drugs (N-556, ketotifen and amlexanox) on airway hyperreactivity in Balb/c mice were studied.

METHODS

Mice were immunized with an antigen (ovalbumin; OA) at intervals of 12 days. OA was inhaled 10 days after the secondary immunization. Twenty-four hours after the last inhalation, airway reactivity to acetylcholine was measured and bronchoalveolar lavage fluid (BALF) was obtained.

RESULTS

Three inhalations of OA caused an increase in leucocytes (including eosinophils), accompanied by increases in IL-5 in BALF, and airway hyperreactivity to acetylcholine in Balb/c and WBB6F1- +/+ mice. In WBB6F1-W/Wv mice, antigen inhalation resulted in increases in leucocytes and IL-5 in BALF but did not result in airway hyperreactivity. NC-17 at doses between 10 and 20 micrograms (intratracheal injection) inhibited the antigen-induced eosinophilia but did not affect airway hyperreactivity in Balb/c mice. Three 'anti-allergic' drugs clearly inhibited antigen-induced increases in IL-5 levels and the number of eosinophils in BALF, but did not affect airway hyperreactivity in Balb/c mice.

CONCLUSIONS

These data suggest that mast cells play an important role in the onset of airway hyperreactivity but do not play a role in the production of IL-5 and eosinophilia. Furthermore, indicate that the inhibition of IL-5 is not always associated with a reduction in antigen-induced airway hyperreactivity in mice.

Therapeutic effect of secretin in patients with jaundice; double-blind placebo-controlled multicentric trial

Secretin, a gastrointestinal hormone, has been shown to have a potent choleretic effect. Having already obtained some beneficial effects with secretin in patients with intrahepatic cholestasis, we sought to confirm its effects in a double-blind placebo-controlled study in patients with mild jaundice after acute or during chronic hepatitis, where total bilirubin level was in excess of 4.0 mg/dl for 3 days or more. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and familiar hyperbilirubinemia were excluded from the study. Ninety-three patients were included in this analysis, but the final evaluation covered 69 of them. No statistically significant differences were found in the reduction of serum bilirubin levels between secretin and placebo groups. As a number of patients with liver cirrhosis had been included, the subjects were subdivided into one group with cholestasis in hepatitis and one with liver cirrhosis. In the subgroup of cirrhotic patients who received secretin, serum levels of AST were significantly increased compared with the placebo group. However, since the choleretic effect of secretin is unique, further studies seem to be warranted.

The F wave disappears due to impaired excitability of motor neurons or proximal axons in inflammatory demyelinating neuropathies

OBJECTIVES

Investigation of pathophysiology of F wave disappearance in demyelinating neuropathies.

METHODS

The peripheral motor nerve conduction was studied by motor evoked potential (MEP) on transcranial magnetic stimulation as well as conventional nerve conduction studies before and after the treatment in 26 patients with inflammatory demyelinating neuropathies. In addition, serum antiganglioside antibodies in the acute or active stage were examined.

RESULTS

The F wave was abolished in 10 patients. Seven of the 10 patients showed motor evoked potentials (MEPs) on transcranial magnetic stimulation that ranged from 1-4 mV. In six of them the F wave reappeared in the recovery stage, but the MEP size did not change. This may be caused by humoral factors, because the F wave reappeared immediately after plasma exchange or intravenous immunoglobulin treatment. A correlation of F wave disappearance with the presence of serum antiganglioside antibodies was found.

CONCLUSIONS

The major pathophysiology of F wave disappearance in demyelinating neuropathies is impairment of motor neuron excitability or prolonged refractoriness of the most proximal axon for backfiring. The conventional interpretation that absent F waves suggest a conduction block at the proximal site is often inadequate.

Effect of tamsulosin, a novel alpha 1-adrenoceptor antagonist, on urethral pressure profile in anaesthetized dogs

1. The effect of tamsulosin (YM617, (R) (-)-S-[2-[[2-(o-ethoxyphenoxy)ethyl]amino] propyl]-2-methoxybenzenesulfonamide HCl), a potent and selective alpha 1-adrenoceptor antagonist, was examined on urethral pressure profile (UPP) and mean arterial blood pressure (MBP) in pentobarbital anaesthetized male dogs. 2. Selective alpha 1-adrenoceptor antagonists tamsulosin (1-100 micrograms kg-1 i.v.), prazosin (1-100 micrograms kg-1 i.v.) and bunazosin (1-100 micrograms kg-1 i.v.) produced a dose dependent reduction in prostatic pressure in the UPP. Doses required to reduce prostatic pressure in UPP by 30% were 3.6 +/- 0.8 (n = 8), 6.9 +/- 1.5 (n = 8) and 4.6 +/- 0.9 (n = 8) micrograms kg-1 i.v., respectively. At the highest dose, tamsulosin exerted less hypotensive effect than prazosin and bunazosin. 3. The calcium antagonist nicardipine (0.1-10 micrograms kg-1 i.v.) and angiotensin converting enzyme inhibitor captopril (10-1,000 micrograms kg-1 i.v.) reduced MBP in a dose dependent manner, but exerted no effect on prostatic pressure in the UPP. The diuretic trichloromethiazide (1-100 micrograms kg-1 i.v.) exerted no effect on UPP or MBP. Treatment with nicardipine (3 micrograms kg-1 i.v.), captopril (100 micrograms kg-1 i.v.) or trichlormethiazide (100 micrograms kg-1 i.v.) did not affect relaxant effect of tamsulosin on prostatic pressure in UPP, or potentiate its hypotensive effect. 4. These results suggest that the alpha 1-adrenoceptor regulates urethral pressure as well as blood pressure in anaesthetized dogs, and that alpha 1-adrenoceptor antagonists may be useful in the treatment of micturition disorders associated with benign prostatic hyperplasia. In addition, as tamsulosin decreased urethral pressure with less hypotension, and as its effect was not influenced by treatment with hypotensive drugs, it may be a useful drug for the treatment of micturition disorders with few cardiovascular side effects.

Somatic mosaicism of expanded CAG repeats in brains of patients with dentatorubral-pallidoluysian atrophy: cellular population-dependent dynamics of mitotic instability

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disease caused by unstable expansion of a CAG repeat in the DRPLA gene. We performed detailed quantitative analysis of the size and the size distribution (range) of the expanded CAG repeats in various regions of the CNS of eight autopsied patients with DRPLA. Expanded alleles (AE) showed considerable variations in size, as well as in range, depending on the region of the CNS, whereas normal alleles did not show such variations, which indicates the occurrence of somatic mosaicism of AE in the CNS. The AE in the cerebellar cortex were consistently smaller by two to five repeat units than those in the cerebellar white matter. Moreover, the AE in the cerebral cortex were smaller by one to four repeat units than those in the cerebral white matter. These results suggest that the smaller AE in the cerebellar and cerebral cortices represent those of neuronal cells. The ranges of the AE in the cerebral cortex, cerebral white matter, and cerebellar white matter showed considerable variation ranging from 9 to 23 repeat units, whereas those in the cerebellar cortex showed little variance and were approximately 7 repeat units. The ranges of the AE in the cerebral cortex, cerebral white matter, and cerebellar white matter were much broader in patients with higher ages at death than they were in patients with lower ages at death, raising the possibility that the range of AE increases with time, as the result of mitotic instability of AE.

[A case of the giant and pedunculated thrombus formation in the left atrium with normal mitral valve]

Occurrence of thrombus formation in the left atrium is rare without accompanying abnormalities at the mitral valve. Only a few cases of giant and pedunculated thromboses in the left atrium have been reported in the Japanese literatures. This is a case report of giant thrombus in the left atrium treated surgically. Patient was 61 years old male suffering from palpitation. Physical examination of the heart revealed increased first sound and diastolic rumbling at the apex. ECG revealed atrial fibrillation and LVH. Echocardiography and chest CT demonstrated a huge tumor like mass in the left atrium attached to the septal area. There were no abnormalities found at mitral valvular structures or motion. Catheterization studies revealed no disturbance of valvular functions. Angiographic examination demonstrated smooth surfaced tumor mass occupied left atrium. Coronary angiography revealed significant stenosis in segments 6, 7, 9, 12 and 14. Prior to surgery, patient was diagnosed myxoma of the left atrium and ischemic heart disease. Removal of the mass and CABG were carried out at a same time. Pathology revealed giant and pedunculated globular thrombus. Contributional factors possibly growing of such huge thrombus formation explained resulting from atrial fibrillation and decreased contractile force of the hypertrophied ventricle.

Nonlinear spatial filtering with a dye-doped liquid-crystal cell

Light-induced molecule reorientation in dye-doped liquid crystals has been applied to nonlinear spatial filtering of periodic patterns. Photoisomerization of azo-dye molecules leads to local alignment changes in the liquidcrystal molecules because of interaction among the molecules. Consequently the polarization of transmitted light is modulated, depending on the induced light intensity. By selection of suitable polarization of the transmitted light self-aligned filtering is realized. Both temporal response and filtering efficiencies have been experimentally investigated.

A gene for a dominant form of non-syndromic sensorineural deafness (DFNA11) maps within the region containing the DFNB2 recessive deafness gene

Hereditary hearing loss is divided into two groups, syndromic and non-syndromic, the latter being more common and highly heterogeneous. Linkage analyses were performed on a Japanese family showing a dominant form of non-syndromic progressive sensorineural hearing loss. This gene (DFNA11) was localized within the region of chromosome 11q which contains the second gene for a recessive form of non-syndromic sensorineural hearing loss (DFNB2). Since it has been reported that another gene for dominant non-syndromic hearing loss (DFNA3) has been mapped to the same region as the first gene for recessive hearing loss (DFNB1), it is possible that different mutations in the DFNB2 gene may result in either dominant or recessive hearing loss.

[DNA synthesis in the testes of infertile men with varicocele--image cytometeric analysis of proliferating cell nuclear antigen]

BACKGROUND

The analysis of cell kinetics of germ cells have been implicated as important clue to investigate the etiology of infertile patients. We examined the germ cell kinetics of varicocele testis using proliferating cell nuclear antigen (PCNA) immunostaing by image cytometry (CAS 2000), which is very accurate and useful method to evaluate the staining intensity.

PATIENTS AND METHODS

Testicular biopsy specimen obtained from 28 cases of male infertility with left varicocele and 5 normal controls were quantitatively examined concerning PCNA expression. Positive rate of PCNA (PR) was expressed as the percent of nuclear area positively stained with PCNA monoclonal antibody compared with total nuclear area analyzed in more than 20 seminiferous tubules. A hematoxylin and eosin-stained sections, which were fixed in Bouin's solution were used to examine Johnsen's mean score by photomicroscopy.

RESULTS

PR of right and left testes of varicocele patients were 11.3 +/- 4.8% and 11.3 +/- 4.1%, respectively. PR of normal testes was 21.7 +/- 3.1%. PR of each side were reduced similarly and the difference of PR between right and left testes of varicocele patients were not significant. Bilateral PR was 11.4 +/- 4.1%. Bilateral PR was significant lower than that of normal testes (p < 0.001). Concerning varicocele grade, sperm concentration of seminogram, Johnsen's mean score and the improvement of seminogram, no significant correlations between PR and those were observed.

CONCLUSION

PR evaluated by image cytometry is very useful biological parameter to assess the germ cell kinetics. In varicocele patients, not only left side but also right side of testes were deteriorated in the cell kinetics and the decrease in DNA synthesis is one of the causes that have deleterious effects on spermatogenesis.

[Comparison of measuring an area with a planimeter and by rectangular dimensional methods]

We have developed a system that measures the volume of air cells in the temporal bone through computerized digital processing of high-resolution CT images. By using this method, the volume of pneumatization was measured, and the results were compared with the measured area of pneumatization obtained from two conventionally used simple ear X-ray methods (the planimeter and rectangular dimensional methods). A total of 57 ears, from 34 subjects, confirmed as normal by CT were examined. The average volume of pneumatization measured on CT images was 5.97 +/- 4.15ml, and the average areas of pneumatization measured by the planimeter and rectangular methods were 9.08 +/- 5.64 and 17.39 +/- 9.77 cm2, respectively. Graphically, when the volume of pneumatization was plotted on the Y axis and the planimeter-measured area of pneumatization on the X axis, a regression formula of Y = 0.651X + 0.054 was obtained, with a correlation coefficient of 0.89. With the volume of pneumatization plotted on the Y axis and the rectangular-dimensional-measured area of pneumatization on the X axis, the regression formula was Y = 0.375X - 0.559, with a correlation coefficient of 0.88. Both these correlation coefficients were considered high. Furthermore, 3D models of the air cells in the temporal bone were created and compared for patients with high and low correlations. In order to capture the morphological characteristics of these 3D models, they were examined from four different angles (lateral, upper lateral, anterior lateral and upper medial). The results showed that regardless of whether air-cell growth was present in the direction of the apex partise petrosae in patients with a low correlation coefficient, such growth played a major role in the degree of the correlatiton. Future studies will be required to clarify this point, though it can already be said that 3D models are indispensable for studying the air cells in the temporal bone. When we compared the volume and area of pneumatization in the temporal bone at different CT cross-sections, we found correlation coefficients in the vicinity of the canalis semicircularis lateralis of about 0.9 or higher. A statistical comparison of correlation coefficients for the CT, planimeter, and rectangular dimensional methods, made by using the CT cross-section with the highest coefficient, found a significant difference between the CT method and the other two methods (p < 0.05). In other words, the volume of pneumatization can be estimated more accurately with CT images than with simple ear X-rays.

Effect of cytokines on thrombin-stimulated increases in intracellular calcium and PGI2 production by cultured human umbilical vein endothelial cells

The influence of cytokines on intracellular calcium concentration ([Ca2+]i) and the production of prostacyclin (prostaglandin l2; PGI2) by cultured human umbilical vein endothelial cells (HUVEC) were examined. HUVEC were incubated for 24 h in media containing interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN gamma), or interleukin-6 (IL-6), and thrombin-stimulated increases in [Ca2+]i and PGI2 production were then examined. Thrombin-stimulated PGI2 production by HUVEC pretreated with 10 U/mL of IL-1 beta or 200 U/mL of TNF-alpha for 24 h was potentiated, while increases in [Ca2+]i were suppressed. In contrast, HUVEC pretreated with 5000 U/mL of IFN-gamma for 24 h had both enhanced PGI2 production and increases in [Ca2+]i. IL-6 affected neither PGI2 production nor [Ca2+]i in HUVEC stimulated with thrombin. The burst increase in thrombin-stimulated PGI2 production by HUVEC pretreated with cytokines did not correlate with the increase in [Ca2+]i. Cytokines have been reported to induce enzymes involved in the arachidonic acid cascade, such as phospholipase A2 (PLA2) and cyclooxygenase-2 (COX-2). Therefore, the increase in [Ca2+]i does not appear to be as important for thrombin-stimulated PGI2 production as does the induction of these enzymes by cytokines.

Intracellular free Ca2+ movements in cultured cardiac myocytes as shown by rapid scanning confocal microscopy

Two-dimensional images of intracellular free Ca2+ movements in cultured cardiac myocytes were obtained at 33-ms intervals with a Ca(2+)-sensitive fluorescence probe, fluo-3, and a rapid scanning confocal laser microscope, a prototype of Nikon RCM8000. The cells used were isolated from the ventricular myocardium of neonatal mice, cultured for approximately 72 h and loaded with fluo-3. One type of cytoplasmic Ca2+ movement observed was a simultaneous increase in [Ca2+] throughout the cytoplasm, termed a "spike"; another type was a local increase in [Ca2+] propagating in the cytoplasm, termed a "wave." Cells with either spike or wave or both types of movements were observed. Tetrodotoxin (TTX) 10(-5) M, nicardipine 10(-6) M, and increased extracellular potassium concentration (40 mM) selectively inhibited spike, and ryanodine 10(-6) M and cyclopiazonic acid (CPA) 3 x 10(-6) M selectively inhibited wave. These results indicate that spike was triggered by depolarization-induced Ca2+ influx across the sarcolemma, whereas wave was a propagating local increase in Ca2+ due to Ca2+ release from the sarcoplasmic reticulum (SR). On spike, nuclear [Ca2+] was shown to increase and decrease synchronously with cytoplasmic [Ca2+], with a delay and slower time course.

Assessment of visuoperceptual disturbance in children with spastic diplegia using measurements of the lateral ventricles on cerebral MRI

The authors estimated perceptual disturbance in children with spastic diplegia from the difference between the visual and performance IQ scores (VIQ-PIQ) on the Wechsler Intelligence Scale for Children-Revised (WISC-R), having found a strong negative correlation between this score and the PQ obtained on the Frostig Developmental Test of Visual Perception (DTVP). The ratio of the areas of the posterior horns to the anterior horns (P/A) correlated negatively with visuoperceptual disturbance. This ratio can therefore be used to assess perceptual disturbance at an early age in children with spastic diplegia.