Inhibitory effect of CV4151, a thromboxane A2 synthetase inhibitor, on ventricular arrhythmias induced by coronary artery occlusion in rats

The purpose of this study was to determine whether thromboxane A2 (TXA2) is involved in the development of ventricular arrhythmias produced by coronary artery occlusion. Ventricular arrhythmias were induced by coronary artery occlusion in 66 male Sprague-Dawley rats. Rats were separated into 4 groups, and saline (n = 19) or CV4151 (a TXA2 synthetase inhibitor)(10 mg/kg, n = 14; 30 mg/kg, n = 15; or 100 mg/kg, n = 18) was injected intravenously 5 min before coronary artery occlusion. The antiarrhythmic effect of CV4151 was assessed in terms of the number of ventricular premature complexes (VPCs), the combined duration of ventricular tachycardia (VT) and ventricular fibrillation (Vf), the incidence of Vf, and the mortality rate within 30 min after occlusion. The total number of VPCs was as follows; control: 1789 +/- 330 beats: 10 mg/kg group: 1289 +/- 302 beats: 30 mg/kg group: 1008 +/- 229 beats: 100 mg/kg group: 986 +/- 275 beats, with no significant differences between groups. The incidence of Vf was significantly reduced in the 30 mg/kg and 100 mg/kg groups, as was the combined duration of VT and Vf and the mortality rate. Our results indicate that the TXA2 synthetase inhibitor CV4151 reduces the incidence of lethal arrhythmias induced by coronary artery occlusion in rats.

[A 4-week intravenous toxicity study of the active metabolite (NM394) of prulifloxacin (NM441) in rats followed by a 4-week recovery test]

A repeated dose toxicity study of ( +/- )-6- fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H- [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid (NM394), the active metabolite of a new antibacterial agent, prulifloxacin, was conducted in Sprague-Dawley rats. Male and female rats were given the test material intravenously for 4 weeks at doses of 0 (control), 3, 10 and 30 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. There were no treatment-related effects on survival, clinical signs, body weight and food consumption. Ophthalmoscopic and hematologic examinations failed to show any abnormalities related to the treatment. Increased water consumption was observed in the 10 and 30 mg/kg groups. In these dose groups, increased urine volume and lowered urine specific gravity, and crystalline substance and small epithelial cells in urinary sediments were seen. Cloudy urine was also seen in the 30 mg/kg group. Blood chemical examination showed decreased gamma-globulin in the 10 and 30 mg/kg groups and increased BUN and creatinine in the 30 mg/kg group. Pathological changes caused by the treatment were as follows. In kidney, tubular nephrosis with crystalline substance was observed in the 10 and 30 mg/kg groups and its organ weight was increased in the 30 mg/kg group. Cecal weight was increased in the 30 mg/kg group. The above-mentioned changes were reversible except for decreased gamma-globulin. Plasma levels and urinary concentrations of the test material were increased in all dose groups with dose-related manner, whereby no sex differences were observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Toxicological findings were not observed in the 3 mg/kg group. The results show that the NOAEL of NM394 is 3 mg/kg for 4-week repeated dose toxicity in rats.

Tissue-specific regulation of angiotensinogen gene expression in spontaneously hypertensive rats

Angiotensinogen is expressed in many tissues besides the liver. Recent studies have suggested that abnormalities in the regulation of angiotensinogen gene expression may be involved in the development of hypertension. However, little information is available concerning the functional significance of tissue angiotensinogen. In this study, we measured plasma angiotensinogen concentration by radioimmunoassay and examined the expression of tissue angiotensinogen by Northern blot analysis in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Although plasma angiotensinogen concentration in SHR was comparable to that in WKY at 6 weeks of age, it was increased significantly at 14 weeks of age in SHR and became higher than that in WKY. The levels of hepatic angiotensinogen mRNA were similar in SHR and WKY, and the levels of aortic, adrenal, and renal angiotensinogen mRNAs were lower in SHR than in WKY at both 6 and 14 weeks of age. Brain angiotensinogen expression in SHR was higher than in WKY at 6 weeks of age and was comparable to that in WKY at 14 weeks of age. On the other hand, cardiac and fat angiotensinogen mRNA levels were significantly increased at 14 weeks of age in SHR. These results demonstrate that the expression of tissue angiotensinogen is regulated differently in SHR and WKY and indicate that the development of hypertension is accompanied at least temporally with increases in plasma angiotensinogen concentration as well as cardiac and adipogenic angiotensinogen mRNA in SHR.

Growth hormone deficiency in Dubowitz syndrome

Severe short stature as a result of intra-uterine growth retardation is one of the characteristics of Dubowitz syndrome. There have been few reports elaborating growth hormone secretory status in this syndrome. A child with Dubowitz syndrome, who was found to have complete growth hormone (GH) deficiency and who responded to growth hormone therapy, is described. This appears to be the first documentation of GH deficiency in this syndrome.

An intensive chemotherapy of adult T-cell leukemia/lymphoma: CHOP followed by etoposide, vindesine, ranimustine, and mitoxantrone with granulocyte colony-stimulating factor support

SUMMARY

An intensive combination chemotherapy regimen supported by granulocyte colony-stimulating factor (G-CSF) was evaluated in adult T-cell leukemia/lymphoma (ATLL) patients in a multiinstitutional, cooperative study. Vincristine 1 mg/m2 i.v. day 1, Adriamycin 40 mg/m2 i.v. day 1, cyclophosphamide 400 mg/m2 i.v. day 1, prednisolone 40 mg/m2 i.v. days 1 to 3 and 8 to 10, etoposide 35 mg/m2 i.v. days 1 to 8, vindesine 2 mg/m2 i.v. day 8, ranimustine 50 mg/m2 i.v. day 8, mitoxantrone 7 mg/m2 i.v. day 8, and G-CSF 50 mg/m2 s.c. days 9 to 21 were given for 2 to 4 courses every 3 weeks to 83 patients with ATLL. Complete remission (CR) and partial remission (PR) were achieved in 35.8 and 38.3 percent, respectively, of 81 evaluable patients. The median survival of all patients was 8.5 months, with a predicted 3-year survival of 13.5 percent by the Kaplan-Meier method. The median duration of response was 7.6 months (range 0.2-42.7), and 13 patients were alive. Their median survival time was 29.1 months (range 19.2-44.7). In 67.6 percent of courses, white blood cell (WBC) nadirs were < 1.0 x 10(9)/L. Days required for the recovery of WBC from the nadir to > 1.0 x 10(9)/L were <5 days in 71.4 percent of the treatment courses. The G-CSF supported an intensified chemotherapy regimen for ATLL and yielded better response rate and longer survival compared to previous reports in Japan. Because duration of remission is still short, further studies of postremission therapy or other strategies are warranted.

[A 4-week oral toxicity study of prulifloxacin (NM441) in rats followed by a 4-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in Sprague-Dawley rats. Male and female rats were given the test material orally for 4 weeks at doses of 0 (control), 30, 300 and 3000 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. There was one case of death in the 3000 mg/kg group. Grayish green and soft feces, unkempt fur, transient deep respiration and decreased body weight gain were observed in the 3000 mg/kg group. Decreased food consumption and increased water intake were seen in the 300 and 3000 mg/kg groups. Ophthalmoscopic examination failed to show any abnormalities related to the treatment. In urinalysis, crystalline substance in the urinary sediments, cloudy urine and decreased Na+ excretion were observed in the 300 and 3000 mg/kg groups. Increased urine volume, lowered urine specific gravity and decreased K+ and Cl- excretions were seen in the 3000 mg/kg group. Hematologic examination showed decreased Hb, Ht, MCV and MCH and increased WBC in the 3000 mg/kg group. Blood chemical examination revealed increased BUN and decreased K+ and Cl- in the 3000 mg/kg group, and decreased K+ and gamma-globulin in the 300 mg/kg group. Pathological changes caused by the treatment were as follows. Cecal weight was increased in all dose groups. Cecal distention and swelling of its absorptive cells were seen in the 300 and 3000 mg/kg groups. In kidney, tubular nephrosis with crystalline substance was observed in the 300 and 3000 mg/kg groups, and its organ weight was increased in the 3000 mg/kg group. The above-mentioned changes were reversible except for decreased gamma-globulin, increased BUN and urine volume, and lowered urine specific gravity. Ulcer and small cavities associated with proliferation of fibrous tissue in the femoral articular cartilage were observed in the 3000 mg/kg group at the end of recovery period of 4 weeks. Plasma levels and urinary concentrations of active metabolite of the test material were increased in all dose groups with dose-related manner, whereby no sex difference was observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Increased cecal weight in the 30 mg/kg group was considered to be attributable to the pharmacological effect of the test material. The results show that the NOAEL of prulifloxacin is 30 mg/kg for 4-week repeated dose toxicity in rats.

[A 4-week oral toxicity study of prulifloxacin (NM441) in dogs followed by a 4-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in beagle dogs. Male and female dogs were given the test material orally for 4 weeks at doses of 0 (control), 30, 150 and 750 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. Feces containing white material were seen in the 150 and 750 mg/kg groups. Salivation, prone, lateral or sitting position, gait disturbance, and locomotor depression were observed in the 750 mg/kg group. In this dose group, decreased body weight and food and water consumptions were also observed. There were no treatment-related effects on survival. Ophthalmoscopic and electrocardiographic examinations and urinalysis failed to show any abnormalities related to the treatment. Hematologic examination showed decreased WBC in the 750 mg/kg group. Blood chemical examination revealed increased GPT and alpha 2-globulin in the 750 mg/kg group. Pathological changes caused by the treatment were as follows. Rarefaction of matrix, cavitations and erosions in humeral and femoral articular cartilages, and inflammatory cell infiltration in synovium were seen in the 150 and 750 mg/kg groups. Focal hemorrhage in synovium was also observed in the 750 mg/kg group. In kidney, regeneration of tubular epithelium, inflammatory cell infiltration, fibrosis and crystalline substance in the tubular lumen were observed in the 750 mg/kg group. The above-mentioned changes were satisfactorily reversible except for the changes in the humeral and femoral articular cartilages and in the kidney. Plasma levels and urinary concentrations of active metabolite of the test material were increased in all dose groups with dose-related manner, whereby no sex difference was observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Toxicological findings were not observed in the 30 mg/kg group. The results show that the NOAEL of prulifloxacin is 30 mg/kg for 4-week repeated dose toxicity in dogs.

Pro-gastrin-releasing peptide (31-98) as a tumour marker of small-cell lung cancer: comparative evaluation with neuron-specific enolase

We attempted to clarify whether serum levels of a carboxy-terminal fragment of ProGRP, ProGRP(31-98), could serve as a more accurate tumour marker in patients with SCLC than neuron-specific enolase (NSE). ProGRP(31-98) and NSE were measured retrospectively in 101 newly diagnosed untreated patients with SCLC, 111 with non-small-cell lung cancer (NSCLC) and 114 patients with non-malignant lung diseases. ProGRP(31-98) and NSE levels were determined using a sandwich enzyme-linked immunosorbent assay. Sensitivity in SCLC patients was 72.3% for ProGRP(31-98) and 62.4% for NSE. Comparing the area under curve (AUC) of 'receiver operator characteristics' of ProGRP(31-98) with that of NSE, ProGRP(31-98) was the more powerful marker in the diagnosis of SCLC (P = 0.0001). Serum levels of ProGRP(31-98) were higher in the 40 patients with extensive disease than in the 61 patients with limited disease (P = 0.0082). ProGRP(31-98) was significantly higher in patients with pure small-cell carcinoma than in patients with mixed small-cell/large-cell carcinoma (P = 0.02). In serial measurement in 16 patients responding to treatment, a high degree of correlation was noted between the decrease in serum ProGRP(31-98) levels and clinical response during the second week after treatment (P = 0.0045). These results indicate that the determination of serum ProGRP(31-98) levels plays an important role in the diagnosis and treatment of SCLC patients.

Citral, an inhibitor of retinoic acid synthesis, modifies chick limb development

Exogenously applied retinoic acid (RA) is known to affect cartilage pattern in developing and regenerating limbs. There are, however, few reports which analyze the participation of endogenous RA in limb pattern formation. Using an organ culture system, we attempted to reduce the concentration of endogenous RA in the developing chick wing buds by the treatment with citral (3,7-dimethyl-2,6-octadienal), an inhibitor of retinoic acid formation. After this treatment, the cultured wing buds were grafted to the stumps of host embryos. These citral-treated limb buds frequently formed truncated cartilage elements and the defects were rescued by simultaneous treatment with an appropriate concentration of RA. These results suggest that endogenous RA plays a role in chick limb bud development.

Impaired compensatory adaption to B-cell mass reduction in young spontaneously hypertensive rats (SHR)

The aim of this study was to examine the effect of insulin resistance on B-cell function and replication. To this end insulin-resistant spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY) as a control were subjected to 90% pancreatectomy (Px) or sham operation at the age of 4 weeks. Islet function and regeneration were examined 4 weeks after surgery. Plasma glucose levels were higher in SHR than in WKY 4 weeks after Px (488 +/- 30 vs. 395 +/- 31 mg/dl; p < 0.01). In sham-operated animals, plasma glucose responses to intravenous injections of glucose (0.5 g/kg body weight) were much higher in WKY than in SHR, while plasma insulin responses were greater in SHR than in WKY. There was no insulin response to glucose in either strain of Px rats. In sham-operated rats, the insulin content of the remnant equivalent pancreas (4.6 +/- 0.8 vs. 3.0 +/- 0.3 micrograms; p < 0.05) and whole pancreas (62.2 +/- 2.8 vs. 53.3 +/- 2.1 micrograms; p < 0.05) were greater in SHR than in WKY. However, the insulin content was lower in SHR than in WKY (1.9 +/- 0.3 vs. 2.5 +/- 0.7 micrograms; p < 0.05) 4 weeks after Px. Fibrotic degeneration of pancreatic islets was greater in Px-SHR than in Px-WKY. These data suggest that the B cells of SHR are more vulnerable to reduction of islet mass than those of WKY. A diminished capacity for islet cell regeneration in SHR may be linked to insulin resistance presented in this animal model of hypertension.

Distribution of nitric oxide synthase-containing nerves in the aganglionic intestine of mutant rats: a histochemical study

We examined the distribution of nerves containing nitric oxide synthase in the intestine of congenitally aganglionic rats, using a reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemical method for whole-mount and cryostat specimens. A constricted intestinal segment extends from the terminal ileum to the anus in this mutant. No nerve elements with the activity were found in the affected terminal ileum, cecum and proximal colon. Although intrinsic ganglionic neurons were absent along the constricted intestine, nerve fibers with the activity were found in both the submucous and intermuscular layers distal to the proximal colon. These fibers increased in density towards the rectum, forming hypertrophic nerve bundles and unusual fiber networks. However, positive fibers were never seen within the circular and longitudinal musculature of the constricted lesion. Some of these hypertrophic nerve bundles were continuous with ectopic ganglia that were situated in the adventitial connective tissue around the lower rectum and in the submucosa near the anus. The hypertrophic nerve bundles seemed to have an extrinsic origin; some of them may have originated from ectopic ganglia. These results suggest that the defective distribution of nerves containing nitric oxide synthase may be involved in the pathogenesis of congenital colonic aganglionosis.

Expression of CD26/dipeptidyl peptidase IV in adult T cell leukemia/lymphoma (ATLL)

The association of CD26/dipeptidyl peptidase IV (DPPIV) and human T lymphotropic virus type I (HTLV-I) was studied by two approaches. First, we examined the expression of CD26 in peripheral blood mononuclear cells (PBMC) from the patients with adult T cell leukemia/lymphoma (ATLL), an HTLV-I-related malignancy. The expression of CD26 on the surface of PBMC was decreased in all 20 patients with ATLL compared with those from normal individuals (P < 0.01) and the expression of the CD26 gene transcript was not detectable in seven out of eight patients with ATLL. Then we compared the quantity of viral DNA in CD26-negative (CD26-) and CD26-positive (CD26+) cells obtained from 17 HTLV-I healthy carries by using a polymerase chain reaction method. The CD26-cells had a higher copy number of viral DNA than CD26+ cells. These findings indicate that HTLV-I has in vivo tropism to CD26- cells, suggesting that some phenotypes of ATLL cells reflect the in vivo cellular tropism of HTLV-I.

Prevalence, resolution, and determinants of late potentials in patients with unstable angina and left ventricular wall motion abnormalities

Although transient myocardial ischemia such as exercise-induced ischemia has not been reported to be associated with the occurrence of late potentials, the association of late potentials with more profound ischemic damage, which is represented by reversible but prolonged left ventricular wall motion abnormalities, has not been demonstrated. We prospectively evaluated 37 unstable angina patients who had reversible but prolonged wall motion abnormalities after resolution of chest pain and electrocardiogram (ECG) changes. Signal-averaged ECG (SAECG) and echocardiogram were recorded during the acute phase and before hospital discharge. Late potentials were present in 6 (16 percent) patients on the initial SAECG recording and resolved in all 6 patients on the second recording before hospital discharge. Normalization of inferior left ventricular wall motion abnormality and multivessel disease were observed more frequently in patients with late potentials on the initial recording than in patients without (p < 0.05 and p < 0.05, respectively). In conclusion, late potentials were observed in patients who had reversible but prolonged wall motion abnormalities; these late potentials were resolved with improvement of left ventricular wall motion abnormalities. These results suggest that myocardial ischemia with prolonged wall motion abnormalities is a possible mechanism of the occurrence of late potentials.

[A case report of germinoma with syncytiotrophoblastic giant cells (STGC) in the basal ganglia]

We report a case of germinoma with syncytiotrophoblastic giant cells (STGC) in the basal ganglia which was encountered at the Department of Neurosurgery, Hiratsuka City Hospital, Kanagawa, Japan. A 9-year-old boy was admitted to our hospital on September 13th, 1993 because of left hemiparesis and precocious puberty. Endocrinological examination revealed a high serum level of human chorionic gonadotropin (HCG) (290 mIU/ml) and beta-subunit human chorionic gonadotropin (HCG-beta) (1.3 ng/ml). Plain CT scan showed an irregularly-defined mass lesion in the right basal ganglia, which had several low density spots and was inhomogeneously enhanced on contrast CT scan. The tumor developed from the right putamen to the thalamus and showed a tendency towards involvement of the hypothalamic region on MR imaging. We performed a right front-temporal craniotomy on 29th September, 1993, and a piece of the tumor was removed. It was histologically diagnosed to be germinoma with STGC. We treated the patient with carboplatin and etoposide (CBDCA 200 mg/m2day1, VP-16 60 mg/m2day1-5) chemotherapy and radiotherapy (local 30 Gy) after surgery. Postoperative course was good without recurrent signs. He is now in good health and going to elementary school without neurological deficit. There are very few reports of germinoma with STGC arising in the basal ganglia. We provide a new treatment of germinoma with STGC, chemotherapy and radiotherapy after surgery.

Inhibition by acetylsalicylic acid, a cyclo-oxygenase inhibitor, and p-bromophenacylbromide, a phospholipase A2 inhibitor, of both cirrhosis and enzyme-altered nodules caused by a choline-deficient, L-amino acid-defined diet in rats

Effects of inhibitors of arachidonic acid (AA) metabolism on the development of fatty liver, cirrhosis, glutathione-S-transferase placental form (GST-P)-positive nodules and the generation of 8-hydroxydeoxyguanosine (8-OHdG) and thiobarbituric acid-reactive substances (TBARS), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in male Fischer 344 rats by feeding CDAA diets supplemented with the inhibitors for 12 and 30 weeks. Acetylsalicylic acid (ASA) (at doses of 0.1 and 0.2%) and p-bromophenacylbromide (BPB) (0.1 and 0.2%) were used as inhibitors of, respectively, cyclo-oxygenase and phospholipase A2, and quercetin (QU) (0.75 and 1.5%) and nordihydroguaiaretic acid (NDGA) (0.1 and 0.2%) as inhibitors of lipoxygenase. None of the inhibitors affected the development of fatty liver caused by the CDAA diet. ASA at a doe of 0.2% almost completely prevented the appearance of cirrhosis, GST-P-positive nodules, 8-OHdG and TBARS in seven out of 11 (63.7%) rats. BPB at a dose of 0.2% also exerted inhibitory effects on all of these lesions but to a lesser extent than ASA. QU and NDGA exerted inhibitory effects limited to the GST-P-positive nodule case. The results indicate that a perturbed AA metabolism, particularly of the cyclo-oxygenase pathway, derived secondarily from depletion of labile methyl groups or phosphatidylcholine, might play key roles in the cirrhosis, hepatocarcinogenesis and oxidative stress caused by a CDAA diet. The results also indicated a possible involvement of the lipoxygenase pathway in hepatocarcinogenic processes.

Seasonal occurrence of Rhipicephalus sanguineus in Okayama Prefecture, Japan and effect of temperature on development of the tick

The seasonal occurrence of Rhipicephalus sanguineus on dogs was examined at a kennel in Okayama Prefecture, Japan. The number of ticks suddenly decreased after treatment with an acaricide in late August. Small numbers of adults and nymphs were detected in September and October, then ticks were not seen on the dogs early in November, when the mean temperature was below 15 degrees C. Then 3 dogs were found to be infested by some adult ticks toward the end of March, when the mean temperature was about 11 degrees C. The effects of temperature on the oviposition and the development of the tick were examined under laboratory conditions. The larval and nymphal post parasitic period, the pre-oviposition period and the oviposition period were prolonged when the temperature was decreased from 37 to 23 degrees C. The oviposition period was extremely long at 14 degrees C, but the tick could not develop below 14 degrees C. No eggs hatched below 14 degrees C. The ability to attach an engorge of adult ticks was examined under cold conditions. Unengorged adult ticks could attach to rabbits on the ear which were kept in an outdoor kennel in October, November and March, however they could not engorge completely in November. They could not attach on rabbits from December to February. The longevity of the tick was also examined under low temperatures. Unengorged adults could attach and engorge on rabbits after kept at 12 degrees C with 50% relative humidity (RH) for 140 days or 12 degrees C with 50% RH for 40 days followed by 4 degrees C with 50% RH for 100 days. These findings suggest that R. sanguineus could be established in Okayama Prefecture under optimum condition.

Role of transcriptional cis-elements, angiotensinogen gene-activating elements, of angiotensinogen gene in blood pressure regulation

Results of recent genetic studies suggest that the angiotensinogen gene is a possible determinant of hypertension. Using antisense technology, we demonstrated that generation of circulating angiotensinogen is a rate-limiting step in blood pressure regulation. In the present study, we examined how the angiotensinogen gene is regulated in vivo. The transcriptional cis-elements, angiotensinogen gene-activating elements (AGE) 2 and 3, have been reported to regulate angiotensinogen production in human hepatocytes in vitro. To determine the critical transcriptional regulator of angiotensinogen production in vivo, we used synthetic double-stranded oligodeoxynucleotides (ODN) as "decoy" cis-elements to block the binding of nuclear factors to promoter regions of the targeted gene, resulting in the inhibition of gene transactivation. Here we examined whether AGE 2 and AGE 3 in the promoter region of the angiotensinogen gene have a pivotal role in hepatic angiotensinogen production in vivo. Hepatic angiotensinogen mRNA was decreased by the transfection of AGE 2 but not mismatched decoy ODN. Transfection of decoy but not mismatched ODN against AGE 2 resulted in a transient decrease in blood pressure of spontaneously hypertensive rats (SHR), accompanied by a reduction in plasma angiotensinogen and angiotensin II levels. In contrast, transfection of AGE 3 decoy ODN had little effect on blood pressure. Overall, our results demonstrate that transfection of decoy ODN against AGE 2, but not against AGE 3, of the angiotensinogen gene resulted in a transient decrease in high blood pressure of SHR, suggesting that the transcriptional cis-element AGE 2, rather than AGE 3, has an important role in blood pressure regulation through the control of circulating angiotensinogen.

Clinical significance of abnormal postexercise systolic blood pressure response in patients with hypertrophic cardiomyopathy

The clinical significance of abnormal postexercise systolic blood pressure (SBP) response in patients with hypertrophic cardiomyopathy (HCM) was assessed by treadmill exercise testing in 30 normal subjects and 96 patients with HCM. SBP recovery ratios were derived by dividing the SBP at 1 and 3 min after exercise by the peak exercise SBP. The upper normal limit of the SBP ratio was defined by two standard deviations (SD) from the mean in 30 normal subjects. A postexercise SBP ratio that exceeded the upper normal limits of the SBP ratio was considered to be an abnormal SBP response in patients with HCM. Twenty-seven (28%) of 96 patients with HCM showed an abnormal SBP response. Compared with the normal SBP response group (69 cases) among patients with HCM, the abnormal SBP response group had lower SBP response during exercise (22 +/- 25 vs 62 +/- 26 mmHg : mean +/- 1 SD, p < 0.05), more prolonged QRS width (110 +/- 21 vs 92 +/- 20 msec, p < 0.05), higher incidences of ventricular tachycardia (12 vs 7 cases, p < 0.001), and sudden death (7 vs 0 cases, p < 0.0001). The defect area of Tl-201 myocardial scintigraphy was more extensive in the abnormal SBP response group (2.9 +/- 1.7 segments) than in the normal SBP response group (1.1 +/- 1.3 segments, p < 0.05). During atrial pacing (120/min), pulmonary artery wedge pressure was slightly elevated from 10 +/- 2 (at rest) to 14 +/- 3 mmHg (during pacing) (p<0.001), cardiac index showed no significant changes, and time constant T was shortened from 58 +/- 13 to 48 +/- 10 msec (p < 0.001) in the normal SBP response group, but in the abnormal SBP response group pulmonary artery wedge pressure was highly elevated from 12 +/- 5 to 20 +/- 3 mmHg (p < 0.0001), cardiac index was decreased from 2.5 +/- 0.7 to 2.1 +/- 0.6 l/min/m2 (p < 0.05), and the time constant T had no significant changes. These observations suggest that patients with HCM and abnormal postexercise SBP response have an abnormal cardiac response during exercise and extensive myocardial damage.

Stimulation of interleukin-1beta-converting enzyme activity during growth inhibition by CPT-11 in the human myeloid leukemia cell line K562

Camptothecin (CPT) was first extracted from Camptotheca acuminata and has a strong antitumor effect. Its water-soluble derivative, CPT-11, has higher therapeutic efficacy and less toxicity than CPT. Recently, CPT-treated cells have been shown to undergo apoptosis. However, the mechanism of induction of apoptosis by CPT has not been characterized in detail in any type of cells. On the other hand, interleukin-1beta-converting enzyme (ICE) is a mammalian homologue of CED3, a protein required for apoptosis in the nematode Caenorhabditis elegans. To determine how CPT-11 brings about cell death by apoptosis, we investigated the effects of CPT-11 on the expression of ICE activity in K562 cells, which represent human myeloid leukemia cells. The proliferation of K562 cells was shown to be inhibited by the presence of CPT-11 in the culture medium. We also found that the levels of mRNA for ICE in the cells were increased in the presence of CPT-11. Furthermore, we demonstrated that when CPT-11 was added to the culture medium, apoptosis of K562 cells was clearly detected in situ. These features suggested that CPT-11 enhances the apoptotic cell death in K562 cells and that a part of induction of apoptosis by CPT-11 may be correlated with the stimulation of the ICE activity.

[Suspension of ventilation during extracorporeal membrane oxygenation with veno-venous by pass in dogs]

We studied whether extracorporeal membrane oxygenation with a veno-venous bypass would allow withdrawal of mechanical ventilation. Three mongrel dogs were anesthetized with intravenous pentobarbital. A Swan-Ganz catheter was placed via the left jugular vein into the main pulmonary artery, and an extra-long total volume catheter was placed in the right femoral artery. The animals were placed in the lateral position, and cannulas (15 Fr.) were placed in the inferior vena cava and the superior vena cava via the right jugular vein and the right femoral vein. These cannulas were connected to a pump and a membrane oxygenator. When the pump flow was almost the same as the previous cardiac output, the partial pressure of oxygen in the pulmonary artery, was high enough to allow ventilation to be suspended. All dogs survived. This suggests that extracorporeal membrane oxygenation with a veno-venous bypass can allow mechanical ventilation to be suspended during tracheocarinal operations such as tracheocarcinal resection.

A nitric oxide-sensitive electrode: requirement of lower oxygen concentration for detecting nitric oxide from the tissue

In order to directly detect nitric oxide (NO) liberated from isolated tissue, a practical and convenient method using a nitric oxide-sensitive electrode is described. To avoid the nonselective signal caused by ionic substances, the electrode was covered with three layers but remains permeable for gaseous substances. In a solution bubbled with 20% oxygen (pO2, approximately 150 mm Hg), administration of S-nitroso-N-acetyl-d, l-penicillamine (SNAP) at concentrations greater than 10(-7) mol/L elicited an electrode response. Based on a comparison with the chemical determination of NO released from SNAP, the electrode may be able to detect nitric oxide around nmol/L. At least 30 nmol NO per liter in anoxic conditions was reported to be detected by this electrode (Matsui, 1995). In a specially designed small chamber, the electrode was attached on the surface of endothelial side of the isolated aorta of the guinea pig. When carbachol was added to the chamber, the electrode responded when the solution was bubbled with 20% but not with 40% or 95% of oxygen, suggesting a much faster decomposition of nitric oxide in the presence of higher concentrations of oxygen. The electrode response to carbachol was abolished in the presence of NG-monomethyl-L-arginine or nitro arginine. These results suggest that the electrode method described in this manuscript is suitable for detecting nitric oxide liberated from isolated tissues when comparatively low oxygen levels are present in the physiological salt solution.