Transient adenosine infusion before ischemia and reperfusion protects against metabolic damage in pig hearts

We investigated whether transient adenosine (Ado) infusion before ischemia had the same effect on myocardial metabolism and function as ischemic preconditioning (IP). The control (C) group underwent 15 min of coronary artery occlusion followed by 120 min of reperfusion. The Ado group received a 15-min infusion of Ado (200 micrograms.kg-1.min-1) into the left atrium starting 20 min before ischemia. IP was elicited by two cycles of 5-min ischemia and 5-min reperfusion. In the area at risk, tissue levels of ATP, creatine phosphate (CP), and intracellular pH (pHi) were serially measured by 31P-nuclear magnetic resonance spectroscopy in 10 pigs from each group, and percent segment shortening (%SS) was measured in 7 pigs from each group. ATP and pHi were preserved after 15 min of ischemia in both Ado and IP groups [ATP = 64 +/- 7, 76 +/- 6, and 74 +/- 9% of baseline; pHi = 6.35 +/- 0.19, 6.54 +/- 0.11, and 6.64 +/- 0.11 in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. During reperfusion, ATP was restored progressively in both groups [71 +/- 7, 90 +/- 8, and 91 +/- 9% of baseline at 120 min of reperfusion in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. However, in contrast to the IP group, CP was not preserved during 15-min ischemia nor did it show persistent overshoot during reperfusion in the Ado group. There were no significant differences in %SS during ischemia and reperfusion among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetus-specific CYP3A7 and adult-specific CYP3A4 expressed in Chinese hamster CHL cells have similar capacity to activate carcinogenic mycotoxins

To assess whether CYP3A4 and CYP3A7 have a similar capacity to activate carcinogenic mycotoxins, we established cell lines stably expressing human CYP3A4 and CYP3A7, which are adult- and fetal-specific forms of cytochrome P450 in human livers, respectively. Each cDNA was introduced into CR-119 cells which had been established by introducing guinea pig NADPH-cytochrome P450 reductase cDNA into Chinese hamster lung cells. The cell lines (4-line and 7-line) stably expressed the mRNA and the protein corresponding to CYP3A4 and CYP3A7, respectively. The concentration-response for aflatoxin B1 (AFB1) cytotoxicity in 4-line and 7-line, respectively, was compared. 4-10 and 7-40 cells were approximately 17- and 20 times more sensitive to AFB1 than the parental CR-119 cells, respectively. In addition, the sensitivities to AFB1 of both 4-10 and 7-40 cells were enhanced approximately seven times by the addition of 10 microM alpha-naphthoflavone, a known activator of CYP3A enzyme, while the sensitivities were suppressed approximately four times by the addition of 100 microM troleandomycin, which forms a metabolite intermediate complex with CYP3A enzyme. Moreover, both cell lines showed approximately 10 and 2 times higher sensitivity to sterigmatocystin and aflatoxin G1 than CR-119 cells, respectively. These results indicate that CYP3A4 and CYP3A7 have essentially similar capacities to activate AFB1, sterigmatocystin, and aflatoxin G1 to produce toxic metabolites.

Metabolic alterations in the neonate and infant brain during development: evaluation with proton MR spectroscopy

PURPOSE

To evaluate the usefulness of hydrogen-1 magnetic resonance (MR) spectroscopy in the evaluation of the developing brain.

MATERIALS AND METHODS

Localized MR spectra were obtained with an echo time of 272 msec from the brain of 78 neonates and infants aged 1 week to 100 months. All patients were retrospectively classified into three groups on the basis of neurologic development: abnormal (group 2, n = 21), normal despite minor neurologic signs (group 1, n = 23), and normal (group 0, n = 34).

RESULTS

Seventeen patients in group 2 and eight patients in group 1 revealed abnormally low N-acetylaspartate (NAA)/choline or NAA/creatine ratios compared with those obtained in group 0. MR spectroscopy was slightly more useful in the differentiation of patients in groups 2 and 1 (chi 2 test, P < .005) than MR imaging (P < .01).

CONCLUSION

H-1 MR spectroscopy provides prognostic information about the brain in healthy and neurologically damaged infants and augments the value of MR imaging.

[Optimal concentration of contrast medium in helical CT of the thorax]

In 99 examinations of 89 patients, we took CT images of the chest after administering one of three concentrations of contrast medium (iohexol 140 mgI/ml, 240 mgI/ml, 300 mgI/ml) to determine the optimal iodo-concentration for intravenous contrast enhancement in spiral CT. Attenuation values of the superior vena cava, ascending aorta, descending aorta, and pulmonary artery were measured to evaluate the degree of contrast enhancement. Five radiologists judged the image quality by scoring factors such as vascular opacification, delineation of the lung and chest wall, detectability of calcification, lymphadenopathy and pulmonary nodules, and the presence of artifacts. The relationships between the iodo-concentration and the scores were analyzed statistically. The higher the iodo-concentration of the contrast medium administered, the stronger the vascular structures were opacified. There was also a concurrent improvement in the detection of lymphadenopathy. However, artifacts appeared on the administration route as a result of the high-concentration contrast medium, and the image quality was degraded. Among the three groups, iohexol 240 mgI/ml exhibited the best performance, namely, good image quality, so that a high degree of contrast enhancement of the vasculature was obtained with few artifacts due to the contrast medium. However, we believe that iohexol 140 mgI/ml presents no significant problems in routine studies.

Serial proton magnetic resonance spectroscopy in a patient with the interval form of carbon monoxide poisoning

Serial proton magnetic resonance spectroscopy (1H-MRS) studies were performed from immediately after the appearance of sequelae in a patient with the interval form of carbon monoxide (CO) poisoning. The volume of interest was set over the frontal lobe white matter. In the early period a persistent increase in choline was found, which was thought to reflect the course of progressive demyelination. The appearance of lactate and decrease in N-acetylaspartate reflected the point at which neuron injury became irreversible. These were followed later by the finding of irreversible changes on MRI and single photon emission computed tomography. The findings suggest that 1H-MRS may be a useful modality to determine neuron viability and prognosis early in the course of the interval form of CO poisoning.

Effects of neuromedins and related peptides on the body temperature of rats

Neuromedin B (NMB) and neuromedin C (NMC) are peptides found in the mammalian central nervous system, and their concentrations are particularly high in the hypothalamus. The amino acid sequences of these peptides are similar to that of bombesin, which is known to induce marked hypothermia not only in amphibians but also in mammals. The effect of neuromedins and related peptides on the body temperature regulation was examined in the rat under a thermoneutral environment. The findings indicated that NMC caused moderate hypothermia following intracerebroventricular administration, while the effect of NMB was meager, suggesting that these two neuropeptides possess different physiological functions in the brain.

Molecular cloning and functional expression of a mouse cytochrome P-450 (Cyp3a-13): examination of Cyp3a-13 enzyme to activate aflatoxin B1 (AFB1)

A cDNA encoding a novel member of the cytochrome P-450 superfamily, Cyp3a-13, has been isolated from mouse liver cDNA library by hybridization screening. The Cyp3a-13 encoded 503 amino acid residues and shared 71% amino acid identity with Cyp3a-11. When Cyp3a-13 cDNA was expressed in CR119 cells which had been established as a cell line stably expressing NADPH-cytochrome P-450 reductase cDNA of guinea pigs, aflatoxin B1-dependent cytotoxicity was observed. This cytotoxicity was enhanced by alpha-naphthoflavone (7,8-benzoflavone), which is known to augment the CYP3A enzymatic activity. The results indicate that CYP3A in mice, which are relatively insensitive to aflatoxin B1, can activate aflatoxin B1 to a genotoxic product.

A novel form of mouse cytochrome P450 3A (Cyp3a-16). Its cDNA cloning and expression in fetal liver

A complementary DNA clone coding for a novel form of cytochrome P450, Cyp3a-16, in mouse fetal livers was isolated and completely sequenced. This clone encoded a polypeptide of 504 deduced amino acids and showed 87.3% and 66.6% amino acid identities with mouse Cyp3a-11 and Cyp3a-13, respectively. Cyp3a-16 transcript was detectable before birth and remarkably diminished five weeks after birth in mice. We conclude that Cyp3a-16 is a fetal- and puberty-specific cytochrome P450 in mice.

Endothelial injury during extracorporeal circulation: neutrophil-endothelium interaction induced by complement activation

This study was designed to understand the physiologic intravascular and intradevice events at the cellular level following complement system activation during extracorporeal circulation. The addition of anaphylatoxin C5a or complement-activated serum into neutrophil- or endothelial cell-suspensions resulted in a dose-dependent transmembrane stimulation that was assessed by an intracellular free calcium ion mobilization technique using a calcium-sensitive photoprotein, aequorin. The adhesion and ruffle formation of neutrophils on endothelial cell monolayers were markedly enhanced when both cell types were treated with C5a or activated serum. The significance of complement activation on intravascular events during extracorporeal circulation is emphasized and discussed from the viewpoint of surface-expressed adhesion molecules.

Species differences in the inhibiting effect of fluvastatin, a new inhibitor of HMG-CoA reductase, on cholesterol biosynthesis

Cholesterol synthesis both ex vivo and in vivo in liver and ileum of hamsters was significantly inhibited by fluvastatin. This ex vivo inhibition was considerably lower in fluvastatin-treated hamsters than in fluvastatin-treated rats. In hamsters and rats, fluvastatin was more potent than pravastatin on inhibitory activities of sterol synthesis in liver, but not in the hamster ex vivo. This may indicate that, in part, the hydrophobicity of the fluvastatin molecule confers the selectivity and metabolism in the liver of hamsters and rats to originate from the species differences.

Kinetic study of quenching reactions of singlet oxygen and scavenging reactions of free radicals by alpha-, beta-, gamma- and delta- tocopheramines in ethanol solution and micellar dispersion

Quenching reactions of singlet oxygen and scavenging reactions of free radicals by alpha-, beta-, gamma- and delta-tocopheramines (Toc-amines) were investigated spectrophotometrically in ethanol and Triton X-100 micellar dispersions. The rate constants of quenching of singlet oxygen (kQ) by alpha-, beta-, gamma- and delta-Toc-amines increased as the total electron donating capacity of the methyl groups at the aromatic ring increased. A plot of logkQ vs. peak oxidation potential (Ep) was found to be linear and the slope was negative. Similar results were obtained for scavenging of a phenoxyl radical (PhO.). The results suggest that charge transfer plays an important role in these reactions. The kQ values were found to be 1.30-2.57 times as large as kQ for alpha-tocopherol (alpha-Toc). Although alpha-Toc has the highest antioxidant activity among natural tocopherols and related phenols, Toc-amines also can serve as antioxidants.

Studies on thermophile products. X. Further biological properties of isofatty acid-containing phosphatidylglycerol that enhances the induction of suppressor T cells

Isofatty acid-containing phosphatidylglycerol (Fr. 7-C), isolated from Bacillus stearothermophilus UBT8038, enhances the induction of concanavalin A (Con A)-activated suppressor T (Ts) cells in a dose dependent manner (0.01-1 microgram/ml). Its further biological properties on mouse mixed lymphocyte reaction (MLR) has been demonstrated. Fr. 7-C (0.01-1 microgram/ml) suppressed the MLR at 4 d in a dose-dependent manner when added at the start of splenocyte cultivation. Moreover, Fr. 7-C was effective in preventing the generation of cytotoxic T lymphocytes after the MLR. On the other hand, this fraction significantly enhanced the induction of Ts cells in the MLR carried out in any of the antigen-specific, antigen-nonspecific and major histocompatibility complex antigen-nonrestricted fashions. Fr. 7-C increased prostaglandin E2 (PGE2) release approximately 2-fold in the culture supernatant of Con A-activated splenocytes, and PGE2 release decreased dose-dependently when cultured with indomethacin. The inhibitory effect by Fr. 7-C on the MLR was abrogated by the addition of indomethacin. The enhancement by Fr. 7-C on Ts cell induction was blocked by indomethacin in a dose dependent manner. These results strongly suggest that Fr. 7-C suppresses the MLR via the enhancement of antigen-nonspecific Ts cell induction mediated at least partly by PGE2.

Aldecalmycin, a new antimicrobial antibiotic from Streptomyces. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties

A new antibiotic, aldecalmycin, has been discovered in the culture broth of Streptomyces sp. MJ147-72F6. Aldecalmycin was purified by solvent extraction, Diaion HP-20 chromatography, silica gel chromatography, Sephadex LH-20 chromatography, HPLC and centrifugal partition chromatography. The 1H and 13C NMR spectra of aldecalmycin showed the presence of keto-enol tautomers. Aldecalmycin is equipotent in inhibiting the growth of sensitive and methicillin-resistant Staphylococcus aureus (MRSA).

Prevention of delayed vasospasm by an endothelin ETA receptor antagonist, BQ-123: change of ETA receptor mRNA expression in a canine subarachnoid hemorrhage model

The authors investigated the roles of endothelin (ET)-1 and the ETA receptor in the pathogenesis of delayed cerebral vasospasm following subarachnoid hemorrhage (SAH). A study was made of the preventive effect of a novel ETA receptor antagonist, BQ-123, on vasospasm and the expression of the ETA receptor messenger ribonucleic acid (mRNA) using a canine two-hemorrhage SAH model. Continuous intrathecal administration of BQ-123 (5 x 10(-6) mol/day) prevented narrowing of the basilar artery on Day 7 after SAH in 97.6% of cases in the study group versus 70.7% of cases in the control group (p < 0.05). While expression of the mRNA-coding ETA receptor was not detected in the control animals, it markedly increased on Day 3 after SAH and was also detected on Day 7. The results suggest that endothelin-1 and the ETA receptor participate in the pathogenesis of delayed cerebral vasospasm following SAH.

CT findings in groove pancreatitis: correlation with histopathological findings

OBJECTIVE

To clarify the CT characteristics of groove pancreatitis, which is a segmental form of chronic pancreatitis.

MATERIALS AND METHODS

The CT findings in four patients with proved groove pancreatitis were reviewed retrospectively. The examinations consisted of plain CT, dynamic CT, and high dose enhancement CT in each patient. Correlation between the CT findings and the resected specimens was performed in three patients.

RESULTS

In every patient a mass was detected in the head of the pancreas that involved the duodenum. Dynamic CT demonstrated a poorly enhancing lesion extending between the pancreatic head and the duodenum. Cysts in the duodenal wall and/or the groove and duodenal stenosis due to wall thickening were seen in four and three patients, respectively. These CT findings reflect the histological characteristics of this disease.

CONCLUSION

Computed tomography, including dynamic study, can demonstrate the characteristic findings of groove pancreatitis and suggest the diagnosis.

Portal venous invasion by pancreatobiliary carcinoma: diagnosis with intraportal endovascular US

PURPOSE

To evaluate use of intraportal endovascular ultrasonography (IPEUS) in diagnosing portal venous invasion by pancreatobiliary carcinoma.

MATERIALS AND METHODS

IPEUS was performed in 26 consecutive patients with pancreatobiliary carcinoma. All patients underwent surgery. IPEUS was performed intraoperatively in 20 cases and preoperatively in six. The sonographic criterion for detection of portal venous invasion was obliteration of the echogenic band of the portal vein. The IPEUS results were compared with those of computed tomography (CT) and arterial portography.

RESULTS

Vascular invasion was confirmed with use of resected specimens in seven patients and operative findings in five patients. For diagnosis of portal venous invasion, the sensitivity, specificity, and overall accuracy of IPEUS were all 100%; respective values were 92%, 64%, and 77% for angiography and 50%, 79%, and 65% for CT.

CONCLUSION

IPEUS allows detection or exclusion of early invasion of the portal venous wall by pancreatobiliary carcinoma.

Differences in the entire nucleotide sequence between hepatitis B virus genomes from carriers positive for antibody to hepatitis B e antigen with and without active disease

The entire nucleotide sequence was determined for eight hepatitis B virus (HBV) genomes from three symptom-free carriers, two patients with chronic persistent hepatitis and one patient with chronic active hepatitis, who were positive for antibody to hepatitis B e antigen (HBeAg). The two patients with chronic persistent hepatitis were tested again after they developed chronic active or fulminant hepatitis, making a total of eight samples. Six had a point mutation in the preC region prohibiting the encoding of HBeAg precursor, while the remaining two had a deletion of 8 or 21 nucleotides within the X gene upstream of the preC transcription initiation sites which would affect the X gene and the putative preC/C promoter. Most genomes from the three symptom-free carriers and the two patients with chronic persistent hepatitis, with HBV DNA levels of 10(2)-10(3)/ml, had deletion, frameshift mutation, initiation failure or a premature stop codon, rendering them replication-incompetent. In contrast, such mutations were rarely seen in HBV genomes from the two patients with chronic persistent hepatitis after they had developed active or fulminant hepatitis and from the patient with chronic active hepatitis, all of whom had vigorous HBV replication with serum HBV DNA from 10(6) to 10(9)/ml. Unique mutations for amino acid changes were more frequent in HBV genomes with a higher replicative activity. These results indicate two kinds of HBV genomes with an HBeAg-minus phenotype, one with defects seriously affecting viral replication and the other without such defects, which would account for different clinical profiles in carriers with antibody to HBeAg.

[Clinical study of neoadjuvant intraarterial chemotherapy (I A-MAC) for advanced bladder cancer]

The clinical efficacy of intraarterial neoadjuvant chemotherapy with MTX, ADR and CDDP in 88 patients with advanced bladder cancer (> or = T2 or TCC G3) was evaluated. The intraarterial chemotherapy was performed using Seldinger's method. The three drugs were administered at the same time among 60 patients. In sixteen patients MTX was administered intravenously before intraarterial infusion of ADR and CDDP. In twelve patients, a high dose of CDDP (more than 100 mg/m2) was administered. The mean regression rate was 70%. That of the high-dose CDDP group was rather superior to the other two groups. However, the adverse reaction and duration of recovery were inferior to those of the other two groups. When intraarterial chemotherapy is performed as a neoadjuvant chemotherapy, care must be taken to determine the suitable dose.

Studies on thermophile products. IX. Isofatty acid-containing phosphatidylglycerol that enhances the induction of concanavalin A-activated suppressor T cells

A new enhancer of the induction of concanavalin A (Con A)-activated suppressor T (Ts) cells has been demonstrated in the ethanolysate of Bacillus stearothermophilus UBT8038. It was purified by successive silica gel column chromatographies and identified as phosphatidylglycerol with C14:0-C18:0 isofatty acids (Fr. 7-C). Mouse splenocytes activated with Con A and Fr. 7-C (0.01-1 microgram/ml) in vitro significantly suppressed the proliferative response of syngenic splenocytes by mitogen stimulation in a dose-dependent manner, compared to those stimulated by Con A alone. The immunosuppressive response enhanced by Fr. 7-C disappeared when the cell populations of Thy-1.2 or CD8 positive lymphocytes were depleted. The result strongly suggests that Fr. 7-C is an immunosuppressive substance which enhances the induction of Con A-activated CD8 positive Ts cells.