Expression of c-fos gene inhibits proteoglycan synthesis in transfected chondrocyte

The effect of expression of c-fos gene on proteoglycan synthesis, one of the important markers of cartilage metabolism, was examined by introducing the c-fos DNA into HCS 2/8 chondrocytes. The [35S]sulfate incorporation into proteoglycan was decreased in the c-fos transfectants expressing exogenous c-fos mRNA, when compared to a control transfectant. A significant increase in transcription of MMP-3 with the suppressed transcription of aggrecan and TIMP-1 were also observed in the c-fos transfectants. Moreover, analysis of the effect of AP-1 proteins on the collagenase and TIMP-1 promoters in gastric carcinoma KKLS cells revealed that c-Fos combined with any of the Jun-related proteins failed to stimulate the TIMP-1 promoter, though collagenase promoter was effectively activated by any Fos/Jun-related protein heterocomplex. These findings indicate that the c-fos expression may govern the cartilage metabolism and hence may play an important role in the pathogenesis of joint destruction in arthritis.

Effect of pharmacotherapy on serum cholesterol levels in patients with panic disorder

It is unclear whether elevated cholesterol level is a complication of panic disorder (PD) or is associated with pharmacotherapy. We compared the total cholesterol (TC) level in 47 PD patients with that in 47 gender- and age-matched normal controls (NC), and we also examined the pre- and post-treatment TC levels. There was no sex difference in TC. Before pharmacotherapy, the mean TC level in the PD group (194.9 +/- 39.6 mg/dl) was non-significantly higher than that in the NC group (190.5 +/- 26.7 mg/dl). The mean TC level in the PD group was significantly reduced following the pharmacotherapy (post-TC: 184.7 +/- 31.0 mg/dl; t = 2.44, P < 0.02), and the subgroup treated with alprazolam (n = 26) showed markedly significant decrease of TC after the treatment (t = 2.36, P < 0.03). The TC level in the PD subgroup with agoraphobia (n = 24, 198.9 +/- 37.9 mg/dl) was slightly higher than that in the group without agoraphobia (n = 23, 190.8 +/- 41.6 mg/dl). These findings suggest that there is a relationship between cholesterol levels and treatment in PD.

Identification and antimicrobial activity of urinary metabolites of a rifamycin derivative in dog

1. Three metabolites of the antimicrobial agent 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin (KRM-1648) were isolated from dog urine obtained after administration of a single oral dose. These metabolites of KRM-1648 were identified by mass spectrometry and 1H and 13C-nmr spectrometry. 2. Three metabolites of KRM-1648 were identified as 25-deacetyl KRM-1648, 30-hydroxy KRM-1648 and 25-deacetyl-30-hydroxy KRM-1648. 3. The antimicrobial activities of 25-deacetyl KRM-1648 were comparable with those of the parent compound, whereas 30-hydroxy KRM-1648 was equipotent and 2-8-fold less active than the parent compound against bacteria and mycobacteria, respectively.

Auditory plasticity in cochlear implant patients

Dynamic range (DR) of cochlear implant electrodes and speech recognition scores (SRS) were chronologically studied in 23 post-lingually deaf subjects over a period of one year. DR significantly increased over one year (ANOVA, p = 0.03). When DR was compared among three groups of electrodes which were located in the inferior, ascending and superior segments of the cochlear basal turn, that in the superior segment showed the largest increase (p = 0.001), followed by those in the ascending and inferior segments. Vowel and consonant recognition scores with auditory cue were best 6 months after operation and were maintained at the level for one year. Although the time course of improvement differed between DR and SRS, a significant positive correlation was observed at 12 months after operation. Improvement of SRS could be a result of a DR increase in the superior segment of the cochlea, which should convey pitch information over the mid-frequency region.

A unique origin and multistep process for the generation of expanded DRPLA triplet repeats

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder associated with the expansion of a CAG repeat at chromosome band 12p13. Epidemiological studies have demonstrated an increased prevalence of DRPLA in Japan, although several DRPLA kindreds of non-Japanese ancestry have been identified. To define the molecular basis for this geographic variation in prevalence, we have analyzed haplotypes around the repeat in several different ethnic groups. Two intragenic biallelic polymorphisms distinguished three haplotypes, each of which formed a predominant haplotype found in the three major racial populations. All the expanded repeats of Japanese and Caucasian patients studied were associated with a particular haplotype, which otherwise was associated with longer repeats commonly found in Asians. Our results support a multi-step model for repeat expansion, and suggest that expanded DRPLA repeats may have evolved from an ancient chromosomal haplotype of Asian origin. We also propose that a combination of a highly polymorphic microsatellite marker with relatively stable biallelic markers in a range of PCR amplification is a powerful tool for studies on human genome diversity, which may reveal the ancient human migration and the formation of ethnic groups.

Effect of omeprazole in the treatment of refractory acid-related diseases in childhood: endoscopic healing and twenty-four-hour intragastric acidity

OBJECTIVE

To determine the clinical efficacy of once-daily treatment with omeprazole in refractory acid-related diseases in children.

METHODS

Endoscopic healing and 24-hour intragastric pH values were assessed in 13 patients with refractory reflux esophagitis (n = 5), refractory and/or giant duodenal ulcer (n = 6), or giant gastric ulcer (n = 2). The mean dose of omeprazole was 0.6 mg/kg per day (range, 0.3 to 0.7 mg/kg per day). Pharmacokinetic studies of omeprazole were performed in seven patients.

RESULTS

The cumulative healing rates at 2, 4, 6, and 8 weeks of treatment were 46%, 85%, 92%, and 92%, respectively. Esophagitis in one patient did not heal despite increases in doses of up to 1.6 mg/kg per day (40 mg/day). The mean intragastric pH of omeprazole-treated patients was 5.2 (range, 3.0 to 6.6) and mean hydrogenion activity was 1.78 mmol/L (range, 0.01 to 10.42 mmol/L). There was wide interindividual variation in the reduction of gastric acid production. Mean intragastric H+ activity in omeprazole-treated patients was significantly lower than that of control subjects (p < 0.005) and that of patients treated with histamine type 2(H2)-receptor antagonists (p < 0.05). Mean intragastric H+ activity was not significantly correlated to the area under the concentration-time curve of omeprazole. No severe adverse effects were reported during treatment or at follow-up.

CONCLUSIONS

Omeprazole has a potent antisecretory effect and is a suitable alternative for short-term treatment of refractory acid-related diseases; a relatively low dose (0.6 mg/kg per day) appears to be optimal in most patients. Unhealed esophagitis at 8 weeks of treatment was considered to be refractory to omeprazole.

Hyperinsulinemia and left ventricular geometry in a work-site population in Japan

The present study was designed to test whether hyperglycemia or hyperinsulinemia influences left ventricular mass and geometry. An echocardiogram and 75-g oral glucose tolerance test were performed in 210 normotensive and 180 mildly to moderately hypertensive male workers in a bus company who were free from cardiac diseases and were not taking medication for hypertension and diabetes mellitus. When we divided subjects into four groups according to the left ventricular geometric pattern using left ventricular mass index of 110 g/m2 and relative wall thickness (ratio of 2 x posterior wall thickness to end-diastolic left ventricular diameter) of 0.44, body mass index and systolic blood pressure were higher in those with concentric hypertrophy and eccentric hypertrophy. In addition, hemoglobin A(Ic) level and the sum of fasting and 2-hour postload serum glucose levels were higher in subjects with concentric hypertrophy. In subjects without diabetes mellitus (n=336), 2-hour postload serum insulin level and the sum of fasting and 2-hour postload serum insulin levels tended to be higher in those with concentric hypertrophy and concentric remodeling. In multiple regression analysis, the sum of glucose levels (or hemoglobin A(Ic) level) in all subjects and the sum of insulin (or 2-hour postload insulin) levels in subjects without diabetes mellitus significantly correlated with relative wall thickness, independent of age, systolic blood pressure, and body mass index. Neither glucose nor insulin levels correlated with left ventricular mass index. Our results suggest that hyperglycemia and hyperinsulinemia may promote concentric changes in the left ventricle in normotensive and mildly to moderately hypertensive men.

Ligand activation of overexpressed epidermal growth factor receptor results in colony dissociation and disturbed E-cadherin function in HSC-1 human cutaneous squamous carcinoma cells

Various types of tumors show aberrant expression and overexpression of epidermal growth factor (EGF) receptor and the degree of receptor expression correlates with a malignant phenotype in many epithelial tumors. However, in vitro evidence supporting the advantageous role of receptor overexpression is deficient. In this study, we compared the effects of exogenous EGF on the cell colony morphology in monolayer and collagen gel culture between HSC-1 squamous carcinoma cells overexpressing EGF receptor and their revertant subline cells. These cells formed coherent cell colonies under routine culture conditions, but addition of EGF induced dissociation of cell colonies within 24 h in the parent HSC-1 cells, though not in the subline cells. Since the colony dissociation apparently involved loss of cell-cell adhesion, we also studied the effects of EGF on E-cadherin expression and its function. Cell aggregation assays showed that EGF reduced E-cadherin function dose-dependently in the parent cells, but not in the subline cells. However, immunoblotting analysis and ELISA showed the absence of downregulation or degradation of E-cadherin. Instead, EGF tyrosine phosphorylated cadherin/catenin complex components including beta-catenin and increased the detergent solubility of E-cadherin in the parent cells. These results suggest that EGF modified the functional association between E-cadherin and actin filament through tyrosine phosphorylation of the cadherin/catenin complex and thereby made the adhesion molecule incompetent. Our results indicate that the ligand activation of overexpressed EGF receptor impairs E-cadherin-mediated cell-cell adhesion and causes dissociation of the squamous carcinoma cell colonies, which facilitates tumor cell invasion in vivo. This might be relevant to the advantageous role of EGF receptor overexpression in malignant phenotype of epithelial tumor cells.

K-ras and p53 mutations in stage I gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

BACKGROUND

An anomalous junction of the pancreaticobiliary duct (AJPBD) was thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we compared K-ras and p53 mutations in Stage I gallbladder carcinomas (GC) of patients with AJPBD with those in patients without AJPBD:

METHODS

We examined 6 GC of patients with AJPBD and 20 GC of patients without AJPBD: Immunohistochemistry was performed for p53 protein. K-ras and p53 mutations were examined using genomic DNA extracted from the cancer regions. The methods of polymerase chain reaction (PCR) single strand conformation polymorphism analysis were performed for mutations in exons 5-8 of p53. The methods of PCR restriction fragment length polymorphism were performed for mutation in codon 12 of K-ras.

RESULTS

p53 positivity was 67% in GC of patients with AJPBD and 65% in GC of patients without AJPBD: p53 mutations were found in exons 7 and 8 in GC of patients with AJPBD and in exons 5, 6, and 7 in GC of patients without AJPBD: The incidence of K-ras mutation in GC of patients with AJPBD (50%) was greater than that in patients without AJPBD (6%) (P < 0.05).

CONCLUSIONS

These results suggest that K-ras mutation may be important in the early stage of carcinogenesis of the gallbladder mucosa with AJPBD, and that p53 mutations may also contribute to the early stage of carcinogenesis of the gallbladder mucosa, regardless of AJPBD:

Simplified model of krypton laser-induced thrombotic distal middle cerebral artery occlusion in spontaneously hypertensive rats

BACKGROUND AND PURPOSE

The effects of thrombotic occlusion of the middle cerebral artery on compromised ischemic tissue may be different from and more severe than those of cerebral ischemia induced by mechanical occlusion of the artery. Photothrombosis, which is based on photochemical damage to the endothelium and subsequent platelet aggregation, is an efficient method to induce thrombosis in vivo. This study aimed to improve and simplify this unique method for an ischemia model of middle cerebral artery occlusion in rats.

METHODS

Male spontaneously hypertensive rats (5 to 6 months old, 300 to 450 g) were anesthetized with halothane, endotracheally intubated, and mechanically ventilated. A krypton laser operating at 568 nm was used to irradiate the exposed distal middle cerebral artery with an intact dura above the rhinal fissure. The photosensitizing dye rose bengal (20 mg/kg body wt) was administered intravenously over 90 seconds starting simultaneously with 4 minutes of laser irradiation at a power of 20 mW to cause thrombotic occlusion of this artery.

RESULTS

The irradiated middle cerebral artery was completely occluded by intraluminal thrombi within 3 minutes after simultaneous laser irradiation and rose bengal infusion. Thrombosed materials were not stained by phosphotungstic acid-hematoxylin stain (ie, aggregated platelets lacked apparent fibrin). The mean volume of 3-day-old infarction, indicated by the lack of staining with 2,3,5-triphenyltetrazolium chloride, was 84.8 +/- 17.4 mm3 (mean +/- SD, n = 6).

CONCLUSIONS

We demonstrated a reproducible and minimally traumatic model of brain infarction induced by the thrombotic distal middle cerebral artery occlusion in rats.

Significance of proliferating cell nuclear antigen (PCNA) expression in gastric cancer in relation to lymph node metastasis

Proliferating cell nuclear antigen (PCNA) in gastric cancer was evaluated in relation to lymph node metastasis. A total of 125 gastric cancer patients who underwent gastrectomy were studied immunohistochemically. The PCNA-positive rate of the primary lesion with lymph node metastasis (47.6%) was significantly higher than those in those without metastasis (24.3%, P < 0.0001). The PCNA-positive rate of early gastric cancer was significantly higher in lesions with lymph node metastasis (36.9%) than in lesions without lymph node metastasis (14.7%). However, there was no significant difference between lesions with and without lymph node metastasis in advanced gastric cancer. In addition, the PCNA-positive rate in metastatic lesions (44.6%) was significantly higher than that in the primary lesion (40.0%, P = 0.001). It is concluded that gastric cancer with higher tumor growth activity has a higher rate of lymph node metastasis. Cancer cells in the metastatic foci of lymph node have a higher proliferating activity than that in the primary lesion.

Distribution and physiological roles of ATP-sensitive K+ channels in the vertebrobasilar system of the rabbit

The effect of an opener (levcromakalim) and a blocker (glibenclamide) of ATP-sensitive K+ (KATP) channels was investigated in the vertebrobasilar system of the rabbit. Arterial tension and membrane potential were measured by the isometric tension recording method and the microelectrode technique, respectively. Glibenclamide (10(-6) mol/L) depolarized the membrane and potentiated the contraction to histamine in vertebral arteries. The sensitivity to the relaxant effects of levcromakalim was in the following descending order: vertebral > proximal basilar > distal basilar > superior cerebellar arteries. Vertebral arteries were approximately 50 times more sensitive to levcromakalim than were superior cerebellar arteries. The relaxation to levcromakalim was abolished by glibenclamide (10(-6) mol/L). Glibenclamide attenuated vasorelaxation to adenosine in proximal arteries (vertebral and proximal basilar) but not in superior cerebellar arteries. Levcromakalim (7 x 10(-8) mol/L) and adenosine (10(-5) mol/L) induced glibenclamide-sensitive membrane hyperpolarization in vertebral arteries but not in distal basilar arteries. These results suggest that KATP channels contribute to the determination of resting membrane potential and resting tone in vertebral arteries. Furthermore, there is a marked heterogeneity in the sensitivity to an opener of KATP channels, and the heterogeneity has a functional link to the mechanism underlying vasorelaxation to adenosine in the vertebrobasilar system of the rabbit.

Clinical implications of the 'no reflow' phenomenon. A predictor of complications and left ventricular remodeling in reperfused anterior wall myocardial infarction

BACKGROUND

Recent studies demonstrated that the "no reflow" phenomenon after coronary reflow implies the presence of advanced myocardial damage. In this study, we verified the prognostic value of the detection of this phenomenon by studying complications, left ventricular morphology, and in-hospital survival after acute myocardial infarction (AMI).

METHODS AND RESULTS

The study population consisted of 126 patients with a first anterior AMI. All patients received coronary reflow within 24 hours of onset of symptoms and underwent myocardial contrast echocardiography (MCE) before and shortly after coronary reflow with an intracoronary injection of sonicated microbubbles. From contrast reperfusion patterns, patients were divided into two subsets: those with MCE no reflow (47 patients, 37%) and those with MCE reflow (79 patients). There was no difference in the frequency of arrhythmia or coronary events between the two subsets. Pericardial effusion and early congestive heart failure were observed more frequently in patients with MCE no reflow than in those with MCE reflow (26% versus 4%, P < .05; 45% versus 15%, P < .05, respectively). Congestive heart failure tended to be prolonged in those with MCE no reflow, and 3 patients (7%) of this subset died of pump failure. Left ventricular end-diastolic volume progressively increased in the convalescent stage in patients with MCE no reflow (early versus late, 145 +/- 43 versus 169 +/- 60 mL, P < .001), whereas it decreased in those with MCE reflow (154 +/- 42 versus 144 +/- 44 mL, P < .01).

CONCLUSIONS

The substantial size of the MCE no reflow phenomenon at coronary reflow conveys useful information about an outcome of coronary intervention and left ventricular remodeling in individual patients with anterior wall AMI, although these are suggestive results in a limited number of patients.

Benign fibrous histiocytoma of the femur: review of three cases

OBJECTIVE

Benign fibrous histiocytoma is a tumor with histologic features similar to those of xanthofibromas, which include fibrous cortical defects and nonossifying fibromas, but with different clinical features. This study investigated the findings of benign fibrous histiocytoma on various imaging modalities. It emphasized the importance of clinical and imaging features as well as histologic findings in establishing the diagnosis.

DESIGN

We reviewed three cases of benign fibrous histiocytoma of the femur that had been diagnosed histologically as (fibro)xanthoma during a retrospective analysis of 187 primary benign and malignant bone lesions.

PATIENTS

All the patients were middle-aged women with various knee complaints.

RESULTS AND CONCLUSIONS

Radiologically, the lesions were all lytic with well-defined geographic margins and sclerotic rims. The tumors arose within the medullary cavity in the distal metaphysis of the femur and involved the epiphysis. CT showed lytic destruction with well-defined marginal sclerosis. T1-weighted MR images showed that the lesions had predominantly the same signal intensity as that of skeletal muscle. The lesions were hypovascular on angiography. Bone scintigraphy showed moderately increased uptake. It was concluded that multiple images as well as clinical features can be useful in differentiating benign fibrous histiocytoma from fibroxanthoma, giant cell tumor, and other fibrohistiocytic tumors of bone.

[Fatty acid metabolic disorder detected by 123I-BMIPP SPECT shortly after elective percutaneous transluminal coronary angioplasty]

Decreased or unchanged BMIPP uptake is often observed in the repeated SPECT imaging soon after successful angioplasty, although coronary flow remarkably recovers. To evaluate clinical significance of this phenomenon, 23 patients underwent BMIPP SPECT before elective PTCA (BM-1), soon after PTCA (72 hours, BM-2), and 3 months later (BM-3). SPECT imagings were divided into 7 segments and were semiquantitatively evaluated by 2 cardiologists in the blinded fashion. Decreased uptake at BM-2 compared with BM-1 was evaluated by comparing with stress Thallium-201 SPECT performed in the same schedule but on the different date (TI-1, 2, 3), ischemic manifestation at PTCA, and wall motion change of LVG. Patients with restenosis were excluded from this study.

RESULTS

BM-2 showed decreased uptake in 14 (61%), unchanged in 2 (9%), and increased in 7 (30%) patients, while stress TI showed increased perfusion in all patients. Among 91 myocardial segments correspondent to PTCA vessels, 30 (33%) showed overt uptake reduction, and only 13 (14%) segments showed increased uptake. BM-2 uptake reduction was significantly associated with the absence of collateral artery (odds ratio, OR = 3.1, p <0.01), multi vessel disease (OR = 2.0, p = 0.01), total balloon inflating time (p <0.05), ST elevation on ECG (OR = 3.6, p = 0.01), chest pain during PTCA (OR = 3.1, p <0.1), while pre-dilatation by using small size balloon catheter prevented BM-2 uptake reduction (OR = 6.0, p = 0.01). Multiple logistic regression analysis showed that chest pain, balloon inflating time and pre-dilatation were independently associated with BM-2 uptake reduction. Three months after PTCA. the segments with BM-2 reduction had stress TI uptake similar to the segments without BM-2 reduction, however, they showed poorer recovery of BM-3 uptake and LV wall motion.

CONCLUSION

BMIPP uptake reduction shortly after angioplasty was associated with ischemic manifestation and poor LV motion recovery, thus, it may be a sensitive representation of the stunned myocardium.

Mild hyperglycemia and insulin treatment in experimental cerebral ischemia in rats

We investigated the effects of mild hyperglycemia and insulin treatment on the metabolism of the ischemic brain in spontaneously hypertensive rats with acute hyperglycemia (n = 9), acute hyperglycemia treated with insulin during ischemia (n = 10), and normoglycemia (n = 10). Cerebral blood flow was measured by the H2 clearance method. Cerebral ischemia induced by occlusion of the bilateral carotid arteries. Cerebral glycolytic metabolites were measured enzymatically. Blood glucose levels were significantly higher in hyperglycemic animals (11.8 to 13.7 mM/l) than in normoglycemic animals (6.0 mM/l). At 60 min of ischemia, the blood flow to the parietal cortex was decreased to 3% of the resting value in all groups. Blood glucose levels at 60 min of ischemia in the hyperglycemic rats were 1.9--3 times higher than the treated hyperglycemic rats and normo-glycemic rats. Glucose concentrations were significantly and positively correlated with the ATP level (p < .0001) but not with the lactate levels in the ischemic brain. Our results suggest that mild hyperglycemia may preserve glucose metabolism in the presence of ischemic insult.

Lithium side effects in relation to brain lithium concentration measured by lithium-7 magnetic resonance spectroscopy

1. The relationship between lithium (Li) side effects and brain Li concentration was examined in 17 patients with bipolar disorder treated with Li and other psychotropic drugs. 2. Brain Li concentration was measured by Li-7 magnetic resonance spectroscopy (MRS). Side effects were assessed using the UCLA General Side Effect Rating Scale For Lithium Treatment (GSE). 3. There was no correlation between the total GSE score and the brain, serum, or erythrocyte Li concentrations. Patients with hand tremor had significantly higher brain Li level (0.51 + or - 0.27 mM) than those without apparent tremor (0.36 + or - 0.20 mM), but no significant difference in serum Li level was seen. As far as the patients had hand tremor, they rarely had brain Li concentration less than the therapeutic range (1 of 15 measurement). On the other hand, they often had brain Li levels less than the therapeutic range when they did not have apparent tremor (13 of 52 measurements). 4. This preliminary study suggests that hand tremor is associated with the brain Li concentration.

Isoflurane acts as an inhibitor of oxidative dehalogenation while acting as an accelerator of reductive dehalogenation of halothane in guinea pig liver microsomes

The effects of isoflurane, 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether, on the oxidative metabolism of halothane to produce trifluoroacetic acid (TFA) and on the reductive metabolism of halothane to produce chlorodifluoroethylene (CDE) and chlorotrifluoroethane (CTE) in liver microsomes of guinea pig were examined. Isoflurane enhanced the production of CDE and CTE and inhibited the production of TFA. Isoflurane enhanced cytochrome P450 reduction and formation of an intermediate complex with cytochrome P450 without enhancement of NADPH-cytochrome P450 reductase (EC 1.6.2.4) activity. We conclude that isoflurane interacts with cytochrome P450 to prevent the formation of the halothane-cytochrome P450 complex, causing inhibition of the oxidative dehalogenation. This interaction of isoflurane enhances the reduction of cytochrome P450 and the formation of a reductive intermediate-cytochrome P450 complex under anaerobic conditions causing reductive dehalogenation of halothane.

[Diagnostic assistance system based on possibility for evaluation of long bone tumorous lesions]

We constructed a diagnostic assistance system for long bone lesions using a relational data base management system, in which we categorized radiographic findings of all parameters in various lesions and stored them as degrees of possibility. Possible diagnoses of unknown lesions were listed by max-min calculation between the data base and findings of the lesions. Integration of parameters narrowed the scope of possible diagnoses. Fifty-six cases with long bone lesions were tested. Experts diagnosed correctly up to 64 percent, while the system showed a correct diagnosis rate of 43 percent as the first rank of possibility. However, the system gave 75 percent correct diagnosis when listed up to the third rank, and this increased up to 100 percent at the ninth rank. The rate of true diagnosis by experts did not exceed 73 percent. The diagnostic assistance system based on possibility analysis proved to be useful for suggesting differential diagnoses in diagnosing long bone tumorous lesions from plain radiographs.

L-arginine ameliorates cerebral blood flow and metabolism and decreases infarct volume in rats with cerebral ischemia

Effects of L-arginine, 300 mg/kg, i.p., on the regional cerebral blood flow (rCBF), brain metabolism, and infarct volume were examined in spontaneously hypertensive rats subjected to occlusion of both left middle cerebral artery and left common carotid artery. Rats treated with L-arginine had higher rCBF, determined by hydrogen clearance method, in the ischemic core (7 +/- 1 ml/100 g/min, mean +/- S.E.M.) and penumbral regions (16 +/- 2) than did rats treated with saline (5 +/- 0 and 7 +/- 1, respectively). Simultaneously, L-arginine attenuated metabolic derangement in the ischemic tissue at 60 min, i.e. well maintained adenosine triphosphate (ATP) in ischemic region (1.29 +/- 0.07 mmol/kg in L-arginine group vs. 1.05 +/- 0.06 in saline group), and also close to normal levels in ATP (2.61 +/- 0.02 mmol/kg vs. 2.45 +/- 0.05), glucose (2.29 +/- 0.12 mmol/kg vs. 1.80 +/- 0.17) and lactate (1.63 +/- 0.10 mmol/kg vs. 2.24 +/- 0.21) in periischemic region. In another experiment, the effects of L-arginine on rCBF in the subcortical regions and on infarct volume were evaluated. L-arginine, compared with saline, increased rCBF by 8 ml/100 g/min in the ischemic side and reduced infarct volume by 29% at 24 h of ischemia. These findings support that L-arginine may be potentially useful for the treatment of acute cerebral ischemia.

Inhibitory effect of cold stress against acetaminophen-induced hepatic injury in B6C3F1 and ICR mice

The effect of cold stress (at 0 +/- 1 degree C for 3 h) on acetaminophen-induced hepatic injury was investigated in B6C3F1 and ICR mice. When acetaminophen (250 mg/kg) was injected intraperitoneally in B6C3F1 mice, the plasma GPT activity was significantly increased by 93 or 107-fold at 6 h or 24 h after the drug injection. However, when B6C3F1 mice were exposed to cold stress, the increase in plasma GPT activity induced by acetaminophen was significantly inhibited by 53% and 44%, respectively. On the other hand, when acetaminophen at the same dose was injected in ICR mice, the activity of plasma GPT was increased by 9-fold at 6 h, or 16-fold at 24 h after the drug injection. The increased plasma GPT activity elicited a significant inhibition of 35% and 36%, respectively, by the exposure to cold stress. These results suggest that acetaminophen-induced hepatic injury may be blocked by physical stress in mice.

Can transcranial Doppler really detect reduced cerebral perfusion states?

BACKGROUND AND PURPOSE

This study was designed to determine whether transcranial Doppler ultrasonography (TCD) may detect reduced perfusion states of the brain in patients with hypertension or diabetes mellitus with suspected cerebral atherosclerosis and arteriolosclerosis.

METHODS

We determined blood flow velocity with TCD in the middle cerebral artery and cerebrovascular vasodilator responses to carbon dioxide in 22 patients with or without carotid artery occlusive disease and minor stroke; we compared the results with the measurements of cerebral blood flow and oxygen metabolism by positron emission tomography (PET).

RESULTS

Blood flow velocity measured by TCD correlated with ipsilateral cerebral blood flow measured by PET in frontal, temporal, and striatal regions and throughout the entire hemisphere (P < .05 to P < .005). Relative changes in blood flow velocity and calculated cerebrovascular resistance tested by carbon dioxide inhalation both correlated closely with regional mean transit time (calculated as the ratio of cerebral blood volume divided by cerebral blood flow) in frontal, striatal, temporal, parietal, and occipital regions and also in the entire hemisphere (P < .05 to P < .0001). TCD variables did not correlate with hemispheric measurements of oxygen metabolism by PET.

CONCLUSIONS

Although TCD is not useful in assessing impairments of cerebral metabolism, it is useful for detecting abnormalities of cerebral hemodynamics among patients with risk factors for cerebrovascular disease.

Periventricular haemosiderin deposition in patients with congenital hemiplegia

Two patients with congenital hemiplegia without obvious prenatal, perinatal or neonatal difficulties showed linear low signal intensity lesions along the wall of the dilated lateral ventricles without any parenchymal lesions on T2- and proton density weighted MRI. Haemosiderin deposition secondary to intra-uterine subependymal haemorrhage with intraventricular haemorrhage was considered most likely from the signal intensity, distribution and clinical histories. MRI, which is the only means of detecting haemosiderin deposition, could be beneficial for evaluating the pathogenetic cause of congenital hemiplegia.

Evidence that PGF2 alpha-induced contraction of isolated guinea pig bronchi is mediated in part by release of tachykinins

To investigate whether prostaglandin F2 alpha (PGF2 alpha) stimulates the release of tachykinins and whether the tachykinins play a role in the PGF2 alpha-induced bronchial contraction, we examined the contractile response to PGF2 alpha in the presence or absence of a neutral endopeptidase (NEP) inhibitor phosphoramidon in the guinea pig main bronchus in vitro. Because NEP effectively cleaves tachykinins, we hypothesized that the inhibition of NEP would enhance a PGF2 alpha-induced bronchial contraction if PGF2 alpha stimulates the release of tachykinins. Phosphoramidon significantly enhanced the concentration-response curve to PGF2 alpha. And it also significantly enhanced 10(-5) M PGF2 alpha-induced contraction. The enhancement was significantly attenuated in tissues where the tachykinins had been depleted by treatment with capsaicin. Furthermore, the enhancement of contraction was also significantly attenuated in the presence of tachykinin antagonist FK-224 (10(-5) M). Tetrodotoxin, a sodium-channel blocker that blocks nerve conduction, did not affect the enhancement. From these results we conclude that 1) PGF2 alpha causes the release of tachykinin-like substances, 2) these substances play a role in bronchial contraction in tissues where NEP activity is inhibited, and 3) nerve conduction is not necessary for the release of these substances in the guinea pig bronchus.