Intraosseous ganglion communicating with soft tissue counterpart

We report the imaging and pathological findings of a rare case of intraosseous ganglion communicating with extraosseous counterpart. Both counterparts contain air and show rim-enhancement on T1-weighted images. Histopathologically, the enhanced-rim consists of reactive proliferation of capillary vessels due to degeneration.

Age-related changes in [3H]nimodipine and [3H]rolipram binding in the rat brain

Ageing is associated with changes in neurotransmission which might be correlated with abnormal calcium metabolism. Because there is evidence that nimodipine can enhance the learning abilities of ageing animals and rolipram can enhance the excitability of neurons, providing a functional basis for cognition-enhancing activity, age-related alterations in the binding of voltage-dependent L-type calcium channels and calcium/calmodulin-independent cyclic adenosine monophosphate-selective phosphodiesterase (cyclic-AMP PDE) were studied in 3-week- and 6-, 12-, 18- and 24-month-old Fisher 344 rats by use of receptor autoradiography. [3H]Nimodipine and [3H]rolipram were used to label the voltage-dependent L-type calcium channels and calcium/calmodulin-independent cyclic-AMP PDE, respectively. [3H]Nimodipine binding showed no obvious change in all brain areas of 12- and 18-month-old rats, as compared with 6-month-old animals. In 24-month-old rats, however, [3H]nimodipine binding increased significantly in the striatum and hippocampal CA3 sector. In contrast, [3H]rolipram binding showed no significant change in most brain areas during ageing, except for a transient change only in the hippocampal CA1 sector of 12-month-old animals. [3H]Nimodipine and [3H]rolipram binding showed a significant increase in some brain areas of 3-week-old rats compared with 6-month-old animals. The results indicate that in rats voltage-dependent L-type calcium channels are more susceptible to ageing processes than calcium/calmodulin-independent cyclic-AMP PDE. Our data also demonstrate that voltage-dependent L-type calcium channels and calcium/calmodulin-independent cyclic-AMP PDE might play roles in developmental processes. These findings might help further elucidation of the relationship between age-related neurological deficits and behavioural pharmacology including cognitive function.

Pancreatic ductal adenocarcinoma: preoperative assessment with helical CT versus dynamic MR imaging

PURPOSE

To compare helical computed tomography (CT) and dynamic, magnetic resonance (MR) imaging in the evaluation of pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Dynamic MR images obtained with breath holding, 256 phase- and 512 frequency-encoding steps, 5-mm section thickness, phased-array multicoil, and double-dose gadolinium were available from 21 patients. Dynamic MR images were retrospectively compared with helical CT images in the evaluation of tumor detection, local tumor extension, and vascular involvement.

RESULTS

Tumors were detected on dynamic MR images of 19 of 21 (90%) patients and on helical CT scans of 16 (76%) patients. Dynamic MR imaging had equal or better sensitivity, accuracy, and agreement of tumor grade than did helical CT in the comparison of imaging findings and histopathologic findings. Dynamic MR imaging also had equal or better specificity than had helical CT in determination of local tumor extension and vascular involvement, except in the factors of duodenal invasion and portal venous system involvement. However, there was no statistically significant difference among any of these measurements.

CONCLUSION

Dynamic MR imaging may be better than helical CT in the preoperative detection and evaluation of local tumor extension and of vascular involvement of pancreatic ductal adenocarcinomas.

Effect of nitric oxide synthase inhibitor on age-related changes in second messenger systems and calcium channels in rats

We investigated the effects of age and nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), on protein kinase C (PKC), adenylyl cyclase, calcium/calmodulin-independent cyclic-AMP phosphodiesterase (cyclic-AMP PDE) and voltage-dependent L-type calcium channels in Fischer rat brain using autoradiography. [3H]Phorbol 12,13-dibutyrate (PDBu), [3H]forskolin, [3H]rolipram and [3H]PN200-110 were used to label PKC, adenylyl cyclase, cyclic-AMP PDE and calcium channels, respectively. [3H]Forskolin binding significantly decreased in the striatum, hippocampal CA3 sector, dentate gyrus, hilus, thalamus, substantia nigra and cerebellum of 24-month-old (aged) rats, as compared with 6-month-old (adult) animals. [3H]Rolipram binding also showed an age-related reduction in the thalamus and cerebellum in rats. In contrast, no age-related changes were observed in [3H]PDBu and [3H]PN200-110 binding in the rat brain. Chronic treatment with L-NAME (5 mg/kg, once a day for 4 weeks) showed no significant changes in [3H]PDBu, [3H]rolipram and [3H]PN200-110 binding in aged rat brains. However, this treatment significantly increased age-related decreases in [3H]forskolin binding in the frontal cortex; striatum and hippocampal CA1 sector in rats. The results demonstrate that [3H]forskolin binding in the rat brain is more susceptible to aging processes than [3H]PDBu, [3H]rolipram and [3H]PN200-110 binding. Furthermore, our study shows that chronic treatment with NO inhibitor increases the age associated changes in [3H]forskolin binding in most brain areas of aged rats. These findings suggest that NO may play a key role in the regulation of adenylyl cyclase system during aging processes.

Ion transport systems in the uptake of 99Tcm-tetrofosmin, 99Tcm-MIBI and 201Tl in a tumour cell line

The kinetics, intracellular distribution and effects of ion transport inhibitors on the uptake of 99Tcm-tetrofosmin, 99Tcm-methoxyisobutyl isonitrile (99Tcm-MIBI) and 201Tl were investigated in a tumour cell line. Both uptake and washout of the tracers were measured at specific intervals. Cells were treated with ouabain, dimethyl amiloride (DMA) and bumetanide to observe the effects on uptake, while carbonyl cyanide m-chlorophenylhydrazone (CCCP) was used to study the release of the tracers. The tracers showed similar uptake and washout kinetics. Ouabain inhibited 55-67% of 201Tl, 16-22% of 99Tcm-tetrofosmin and 8-14% of 99Tcm-MIBI. DMA inhibited the uptake of both 99Tcm-tetrofosmin (30%) and 99Tcm-MIBI (21%). Bumetanide stimulated the uptake of 99Tcm-tetrofosmin and 99Tcm-MIBI but inhibited that of 201Tl (37%). When cells were pretreated with various combinations of these ion transport inhibitors, the uptake of 201Tl was related to Na+,K+ pump, Na+,K+, 2Cl- co-transport systems, whereas the uptake of both 99Tcm-tetrofosmin and 99Tcm-MIBI was related to the Na+,K+ pump, Na+/H+ antiport systems. Addition of CCCP released 55% and 90% of accumulated 99Tcm-tetrofosmin and 99Tcm-MIBI respectively, indicating that the percentage released was related to mitochondrial uptake.

Tc-99m-MIBI scintigraphy for detecting parathyroid adenoma and hyperplasia

We performed scintigraphy with technetium-99m-methoxyisobutylisonitrile (MIBI) in 10 patients with parathyroid adenoma (7 lesions) or hyperplasia (9 lesions). Correlation between an amount of accumulation of MIBI and histological types of the lesions were evaluated with special reference to an amount of oxyphilic cell in the lesions. Selected lesions were also evaluated for mitochondrial density by electromicroscopy and showed increased mitochondrial density in the oxyphilic cells. All lesions equal to or above 220 mg showed positive scintigraphic results despite differences in cell types. Undetected lesions were all equal to or below 100 mg. The scintigraphic results for 2 lesions with abundant oxyphilic cells were both positive although those for 11 lesions with abundant chief cells only 6 were positive, probably because these lesions were smaller in the hyperplasia group. In conclusion, MIBI uptake in parathyroid lesions was not dependent on the cell type but either on the size or functional state of the lesions.

The biochemical studies on phalloidin-induced cholestasis in rats

We investigated sequential changes in bile flow, serum and biliary biochemical parameters in phalloidin-induced cholestasis in rats. Intrahepatic cholestasis was induced by administration with phalloidin (500 microg/kg) for 7 days, and then the animals were allowed to survive for 1, 2, 4, 7, 14 and 28 days after the last treatment. In phalloidin-treated rats, bile flow significantly decreased up to 4 days of recovery, compared with the control animals. In contrast, serum ALP activity, LAP activity, cholesterol concentration and phospholipid concentration exhibited a marked elevation throughout the recovery periods. For biliary parameters, bilirubin excretion rate was unchanged but, cholesterol excretion rate showed a marked decrease throughout the recovery periods. These results demonstrate that some parameters, particularly important indexes of cholestasis (serum ALP, cholesterol, bile flow and so on), continued significant changes at least 4 days after the last administration of phalloidin. These results demonstrate that successive treatment with phalloidin can cause damage in most of serum and biliary parameters at a chronic stage of cholestasis. Thus, our findings may provide useful information for diagnosis of drug-induced cholestasis and help to further elucidate the biochemical mechanisms of drug-induced cholestasis in humans.

Fetal plasma lipid peroxide levels in pregnancies complicated by preeclampsia

Fetal levels of a representative lipid peroxide malondialdehyde (MDA) were measured as an index of oxidative stress in pregnancies complicated by preeclampsia (n = 19) and in normal pregnancy (n = 23). PO2, PCO2 and pH were also measured in umbilical venous blood obtained by cordocentesis. Plasma MDA levels rose an average of 26% above those of normal pregnancy (p < 0.05) and the elevation correlated inversely with umbilical venous PO2 and pH. The results indicate that fetal oxidative stress occurs in preeclampsia before the onset of labor.

Age-independent constancy of mineral contents in human vertebra and auditory ossicle

To elucidate age-related changes of mineral contents in human bones, element contents of human vertebrae and auditory ossicles were determined by inductively coupled plasma atomic-emission spectrometry. The cervical, thoracic, and lumbar vertebrae were removed from 12 vertebral columns. The mallei of auditory ossicle were removed from 27 cadavers. It was found that average relative contents (RCs) of calcium and phosphorus in cervical, thoracic, and lumbar vertebrae remained almost constant within ages ranging from 46 to 99 y. In addition, it was found that the RCs of calcium and phosphorus in men's and women's mallei remained constant within ages ranging from 40 to 98 yr. These results support the view that there is no significant age-dependent change of mineral contents in human bones.

Age-related changes of sodium-dependent D-[3H]aspartate and [3H]FK506 binding in rat brain

We investigated age-related changes in excitatory amino acid transport sites and FK506 binding protein (FKBP) in 3-week-, and 6-, 12-, 18- and 24-month-old Fischer 344 rat brains using receptor autoradiography. Sodium-dependent D-[3H]aspartate and [3H]FK506 were used to label excitatory amino acid transport sites and immunophilin (FKBP), respectively. In immature rats (3-week-old), sodium-dependent D-[3H]aspartate binding was lower in the frontal cortex, parietal cortex, striatum, nucleus accumbens, whole hippocampus, thalamus and cerebellum as compared to adult animals (6-month-old), whereas [3H]FK506 binding was significantly lower in only the hippocampus, thalamus and cerebellum. 3[H]FK506 binding exhibited no significant change in the brain regions examined during aging. However, sodium-dependent D-[3H]aspartate binding showed a conspicuous reduction in the substantia nigra in 18-month-old rats. Thereafter, a significant reduction in sodium-dependent D-[3H]aspartate binding was found in the thalamus, substantia nigra and cerebellum in 24-month-old rats. Other regions also showed about 10-25% reduction in sodium-dependent D-[3H]aspartate binding. The results indicate that excitatory amino acid transport sites are more susceptible to aging process than immunophilin. Further, our findings demonstrate the conspicuous differences in the developmental pattern between excitatory amino acid transport sites and immunophilin in immature rat brain.

MR of the endolymphatic duct and sac: findings in Menière disease

PURPOSE

To compare the visibility of the endolymphatic duct and sac on high-resolution MR images with the symptoms and clinical course in patients with Menière disease.

METHODS

Twenty-two patients with unilateral Menière disease were sorted into two groups on the basis of the clinical stage of their disease at the time of imaging. Group 1 included patients in the acute phase, who presented with vertigo. Group 2 comprised patients in the nonacute phase of the disease, who were studied 9 days or more after an episode of vertigo.

RESULTS

During acute attacks, the endolymphatic duct and sac were not adequately visible in the affected ear but were visible in the unaffected ear. During remission, the endolymphatic duct and sac were not observed in clinically advanced patients, but they were seen in patients in the early and intermediate stages.

CONCLUSION

High-resolution MR imaging can be used to evaluate the endolymphatic duct and sac: visible abnormalities and lack of a visible endolymphatic duct and sac correlate with the clinical course of Menière disease.

Anti-atherogenicity in women does not prevent restenosis after balloon angioplasty

To test the hypothesis that anti-atherogenicity in women exerts beneficial effects to prevent restenosis formation after coronary angioplasty, we studied 493 men (988 lesions) and 81 women (159 lesions), aged 40-60 years, who had undergone successful balloon angioplasty and had follow-up angiography, 4.9 +/- 4.1 months later. We compared the extent of restenosis between men and women, and between pre- and post-menopausal women, which was assessed by a categorical definition of restenosis (more than 50% diameter stenosis at follow-up) and by percent diameter measured immediately after angioplasty and at follow-up. Hypertension was more frequent in women and a significantly lower percentage of women smoked. In women, the levels of total cholesterol and low-density lipoprotein cholesterol were higher. The location of dilated lesions, frequency of angioplasty for lesions with chronic total occlusion, and frequency of emergency angioplasty in patients with unstable angina or acute myocardial infarction were similar in men and women. Restenosis formation, estimated by the categorical definition or percent diameter, did not differ between men and women, or between pre- and post-menopausal women. Menopausal status or sex was not an independent predictor of restenosis by multivariate analysis. Thus, the benefit of anti-atherogenicity in women does not play an important role in preventing restenosis after coronary angioplasty.

Effects of chronic treatment with a cyclic AMP-selective phosphodiesterase inhibitor, rolipram, on excitatory amino acid neurotransmission systems in young and aged rat brains

Rolipram selectively inhibits cyclic AMP-specific phosphodiesterase, and leads to an increase in cyclic AMP levels in the brain. In this study, we investigated the effects of chronic rolipram treatment on excitatory and inhibitory amino acid neurotransmission systems in young and aged Wistar rat brains. We used in vitro autoradiography with [3H]MK-801, [3H]glycine, D[3H]aspartate, and [3H]muscimol to label N-methyl-D-aspartate (NMDA) receptors, glycine modulatory sites, glutamate transport sites, and gamma-aminobutyric acid-A (GABA) receptors, respectively. Rolipram (0.01 or 0.1 mg/kg, per os) or its vehicle (distilled water) was administered once a day for 4 weeks. The highest binding of [3H]MK-801, [3H]glycine, and D-[3H]aspartate was seen in the hippocampus in vehicle-treated rats. No significant differences in these binding activities were seen between young and aged rat brains. [3H]Muscimol binding was the highest in the cerebellum, and decreased in many brain regions in aged rats. The chronic rolipram treatment resulted in (1) an increase in [3H]MK-801 binding in the dentate gyrus in both young and aged rats, (2) remarkable reductions in D-[3H]aspartate binding in many regions of both young and aged rats, and (3) no or minimal changes in [3H]glycine and [3H]muscimol binding. These results suggest that the chronic rolipram treatment modifies the excitatory amino acid neurotransmission system.

Effects of vinconate on neurotransmitter receptor systems in aged rat brain

We investigated the effects of age and (±)-methyl-3-ethyl-2,3,3a,4-tetrahydro-1 H-indolo[3,2,1-de][1,5]naphthyridine-6-carboxylate hydrochloride (vinconate), an indolonaphthyridine derivative, on neurotransmitter receptor systems in the rat brain using quantitative receptor autoradiography. [(3)H]Quinuclidinyl benzilate (QNB), [(3)H]hemicholinium-3 (HC) and [(3)H]muscimol were used to label acetylcholine receptors, high-affinity choline uptake sites and γ-aminobutyric acid(A) (GABA(A)) receptors, respectively. [(3)H]QNB, [(3)H]HC and [(3)H]muscimol binding decreased in any brain areas of 24-month-old (aged) rats in comparison with 6-month-old (adult) animals. Chronic treatment with vinconate (10 and 30 mg/kg, i.p., once a day for 4 weeks) partly ameliorated the reduction in [(3)H]QNB, [(3)H]HC and [(3)H]muscimol biding in aged rat brains. This effect was especially noted in [(3)H]muscimol binding. The results suggest that vinconate may have beneficial effects on age-related changes in neurotransmitter receptor systems.

Maternal theophylline administration and breathing movements in late-gestation human fetuses

OBJECTIVE

To investigate the relation between maternal administration of theophylline and breathing movements during late gestation in human fetuses.

METHODS

After a 1-hour control period, 17 women with normally grown fetuses at 33-38 weeks' gestation were given 400 mg of sustained-release theophylline orally. Maternal plasma theophylline and glucose concentrations were measured every hour, and the incidence of fetal breathing movements and breathing rates were measured continuously during the next 8 hours. Results were compared with those of a similar control group that did not receive theophylline.

RESULTS

The maternal plasma theophylline concentration increased to detectable levels after 1 hour, reached therapeutic levels of 6.9 +/- 0.4 micrograms/mL (standard error of the mean) after 6 hours, and thereafter averaged 8.3 +/- 0.3 micrograms/mL, significantly higher than initial control values (P < .05). The mean glucose concentration was unchanged during the first 6 hours (79.2 +/- 1.1 mg/dL) and then decreased somewhat, averaging 75.8 +/- 1.1 mg/dL in the 7-8 hour period. The incidence of fetal breathing increased 26.4 +/- 1.9% after 5 hours and remained elevated during the next 3 hours at levels significantly higher than in the initial control period (P < .05) and higher than in the control group that did not receive theophylline. The mean hourly breathing rate averaged 40.9 +/- 1.3 breaths per minute after ingestion of theophylline, a nonsignificant change.

CONCLUSIONS

Ingestion of theophylline by pregnant women in late gestation is associated with an increase in fetal breathing movements. Theophylline has been used widely in the management of asthma in pregnancy, and the assessment of fetal breathing movements is used routinely for evaluation of fetal status. Therefore, account must be taken of changes in breathing movements caused by maternal theophylline administration.

Adenosine A1-receptor agonist attenuates the light-induced phase shifts and fos expression in vivo and optic nerve stimulation-evoked field potentials in the suprachiasmatic nucleus in vitro

Adenosine is widely accepted to act as an inhibitory neuromodulator in the mammalian central nervous system. In the present study, we examined whether adenosine receptor agonist modifies the photic entraining responses in the rat suprachiasmatic nucleus both in vivo and in vitro. Light (200 lux, 15 min)-induced phase shifts of hamster wheel-running rhythms was attenuated by a systemic administration of A1-adenosine receptor agonist N6-cyclohexyladenosine (N-CHA) in a dose-dependent manner; 0.5 mg/kg N-CHA caused 60% inhibition of light-induced phase shifts. On the other hand, A2-adenosine receptor agonist N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl]adenosine (DPMA) failed to inhibit light-induced phase shifts. Systemic administration of N-CHA but not of DPMA inhibited light (300 lux, 1 h)-induced Fos expression in the suprachiasmatic nucleus in a dose-dependent manner; 1 mg/kg N-CHA caused 73% inhibition of light-induced Fos expression. Bath application of N-CHA but not of DPMA inhibited optic nerve stimulation-evoked field potentials in rat suprachiasmatic nucleus slices. The present results suggest that activation of adenosine A1-receptor attenuates the photic input through the inhibition of retinohypotalamic pathway to the SCN.

Positions of disulfide bonds in yam (Dioscorea japonica) acidic class IL (class IV) chitinase

Yam acidic class I chitinase belongs to a low molecular weight subclass of class I (class IL; corresponds to class IV) chitinase. The positions of disulfide bonds in this chitinase were examined. Chitinase protein was digested with acid protease and thermolysin, and the resulting disulfide bond containing peptides were separated by reversed-phase HPLC and detected using the SBD-F (7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonic acid ammonium salt) method. Four intradisulfide bonds containing peptides were purified and three disulfide bonds in the catalytic domain were identified as Cys-66 and Cys-115, Cys-128 and Cys-136, and Cys-218 and Cys-250. Location of disulfide bonds in the catalytic domain was identical to that of barley class II chitinase but different from rye class II chitinase at the C-terminal. Conservation of S-S bonds at the N-terminal half of the catalytic domain between class I and class II chitinases strongly suggests that this region is important for formation of the active site.

Will thallium-201 replace gallium-67 in salivary gland scintigraphy?

We investigated and compared findings on combined 99mTc pertechnetate-201Tl with those of [99mTc]pertechnetate-67Ga scintiscans to elucidate the advantages of 201Tl in detecting various salivary glands disorders.

METHODS

We studied 23 patients: 6 had sialadenitis, 12 had benign tumors and 5 had malignant tumors. All but four patients had undergone [99mTc]pertechnetate (before and after lemon stimulation), 201Tl (early and delayed) and 67Ga imaging.

RESULTS

Five of six sialadenitis patients showed various degrees of diffuse uptake of 99mTc. All six except one showed early uptake without retention of 201Tl on delayed imaging. The 67Ga scan showed uptake in all patients except one. Nine of 12 benign tumors showed a cold defect on 99mTc scans. Patients with Warthin's tumors and plasmacytoma showed increased 99mTc uptake at the tumor with retention. The 201Tl scan showed early uptake without retention in benign tumors except in three patients, two of whom had Warthin's tumor. Five of the benign tumors, however, were positive on 67Ga scan. None of the malignant tumors showed any uptake of 99mTc. The 201Tl scan showed uptake with tumor retention on delayed images in three patients; three other patients also had positive 67Ga scans. Overall, sensitivity and specificity of 201Tl in detecting malignant tumors were 60% and 73%, respectively, with a negative predictive value of 85%. Sensitivity and specificity for 67Ga were 60% and 47%, respectively, with a negative predictive value of 80%.

CONCLUSION

In view of sensitivity, specificity and convenience of 201Tl as well as future prospects for dual-isotope acquisition, 67Ga may be replaced by 201Tl in detecting salivary gland disorder.

[89Sr Therapy for pain relief in patients with bone metastases]

Radioactive strontium chloride (89Sr) was administered for pain relief in 6 patients with bone metastases (4 prostate cancer and 2 breast cancer patients). Out of 6 patients, 2 showed apparent relief of bone pain and improvement of QOL, and 3 showed slight relief of the pain with or without improvement of QOL; that is, 83% was effective. Side effects were seen in 2 patients; transient deterioration of bone pain in one patient and bone marrow suppression in the other patient. The patient who showed bone marrow suppression had rather more lesions of bone metastasis (diffuse metastasis) and least urinary excretion of the radioactivity. Urinary excretion for 2 days varied 5 to 40% of the administered dose and was less in the patients with more metastatic lesions.

Microglial activation by epileptic activities through the propagation pathway of kainic acid-induced hippocampal seizures in the rat

We studied the distribution of activated microglia in the brain during kainic acid-induced acute hippocampal seizures in rats. Although no microglial activation was observed 4 h after seizure induction, activation was detected in the primary focus and also in other selected structures in the limbic and non-limbic structures after 8 and 24 h, in the absence of any obvious morphological changes in the neurons. The structures with activated microglia were highly consistent with those included in the propagation pathways of the hippocampal seizures. These findings thus suggest that the microglial cells are activated through the propagation pathways by the seizure activities that propagate transynaptically from the primary focus, even without any apparent neuronal injury.

Studies on the magnitude and the mechanism of cough potentiation by angiotensin-converting enzyme inhibitors in guinea-pigs: involvement of bradykinin in the potentiation

One adverse effect of the angiotensin-converting enzyme (ACE) inhibitors used for treatment of hypertension and congestive heart failure is the production of dry coughs. Imidapril is a new type of ACE inhibitor with a very low incidence of coughs. The magnitude and the mechanism of cough potentiation of imidapril and other ACE inhibitors has been studied in guinea-pigs. In normal guinea-pigs single and repeated dosing of imidapril at 0.1 to 100 mg kg-1 had no effect on capasaicin- or citric acid-induced coughs. Single and repeated dosing of enalapril and captopril at 10 to 30 mg kg-1, respectively, significantly increased the number of capsaicin-induced coughs. Repeated dosing of 1 mg kg-1 enalapril also significantly augmented the capsaicin cough. In bronchitic guinea-pigs imidapril also had no effect on the coughs induced by the two stimulants. Enalapril and captopril significantly increased the number of coughs induced not only by capsaicin but also by citric acid. Lower doses of enalapril were enough to augment the capsaicin-induced coughs, whereas medium to large doses failed to augment the cough irrespective of the protocol of administration. Bradykinin-induced discharges of the vegal afferents from the lower airway were significantly increased by enalaprilat but not by imidaprilat. Capsaicin-induced discharges of the afferents were, on the other hand, significantly depressed by enalaprilat, but not by imidaprilat. Interestingly, enalaprilat depression of the discharges was significantly reversed by Hoe-140, a bradykinin B2 receptor blocker. In guinea-pigs pretreated with a low dose of enalapril, arterial infusion of bradykinin significantly potentiated the coughs induced by capsaicin. The results indicated that imidapril was less potent than enalapril and captopril in potentiating cough responses induced by capsaicin and citric acid in guinea-pigs, and further suggest that bradykinin might be a key substance in the mechanism of the potentiation of coughs associated with ACE inhibitors.

Progressive expression of immunomolecules on activated microglia and invading leukocytes following focal cerebral ischemia in the rat

In order to evaluate the involvement of inflammatory reactions following focal cerebral ischemia in the rat, we immunohistochemically visualized microglial cells and blood-borne leukocytes (neutrophils and monocytes) using various antibodies directed against immunomolecules expressed on these cells. Focal cerebral ischemia was produced by intraluminal occlusion of the right middle cerebral artery for 1 h. The brains were perfusion-fixed at 4 h, 1 day, 3 days, 7 days and 14 days after ischemia. Frozen brain sections were prepared and stained with monoclonal antibodies to complement receptor type 3 (OX42), major histocompatibility complex (MHC) class I and class II antigens (OX18 and OX6, respectively), a pan-macrophage/monocyte marker (ED1), intercellular adhesion molecule-1 (ICAM-1), LFA-1 alpha chain (CD11a) and beta chain (CD18), and T cells (CD5). In ischemic areas where infarction developed later, microglial cells were destroyed (beginning at 4 h), neutrophils migrated (1-3 days), and then monocytes/macrophages infiltrated and covered the entire lesions (3-14 days). The invading leukocytes expressed CD11 and CD18 adhesion molecules on their cell surface while ICAM-1 was expressed on endothelial cells. In surrounding areas, in contrast, there was a rapid activation of microglia showing morphological changes and upregulation of OX42 immunoreactivity (4 h-7 days), especially in the transitional rim of the infarct (7 days). ED1 and MHC antigens were expressed on both activated microglia and invading leukocytes. Thus, developing infarction was accompanied by accumulation of inflammatory cells of both intrinsic (microglia) and extrinsic (leukocytes) origins. Thus, results suggest that the relative importance of each source is determined by the time after ischemia and the site within the lesion, and that the expression of immunological molecules plays an important role in eliciting such inflammatory reactions.

Involvement of p53 in DNA strand break-induced apoptosis in postmitotic CNS neurons

The tumour suppressor p53 gene serves as a critical regulator of the cell cycle and of apoptosis following the exposure of normal cells to DNA damage. To examine the role of p53 in postmitotic CNS neurons, we cultured cerebellar neurons from normal wild-type mice and mutant p53-null mice under various conditions inducing neuronal death. When cerebellar neurons from 15- to 16-day postnatal wild-type mice were treated with ionizing radiation or DNA-damaging agents, massive neuron death occurred after 24-72 h. In contrast, neurons from p53-/- mice evidently resisted gamma-irradiation and some DNA-damaging agents, such as etoposide and bleomycin. On the other hand, low-K+ medium-induced apoptosis of cerebellar neurons was not affected by p53 status. Neither cell cycle progression nor DNA synthesis occurred during cell death induced by gamma-irradiation and low-K+ medium, as well as in normal cultures of p53+/+ and p53-/- neurons. These results suggest that p53 is required for the apoptotic death of postmitotic cerebellar neurons induced by DNA strand breaks.