Effects of calcium in continuous cardioplegia on myocardial protection

The effects of calcium (Ca) on a hyperkalemic cardioplegic solution for continuous cardioplegia were examined in an isolated perfused working rat heart model. The coronary arteries were perfused with a modified Krebs-Henseleit bicarbonate buffer (K-H) solution, containing various concentrations of Ca(0.1, 0.6, 1.2, and 2.5 mmol/l) and a high concentration of potassium (20 mmol/l), for 180 min, after which cardiac arrest was induced at 37°C for 180 min. Cardiac function and creatine kinase (CK) were measured. In the control group, K-H solution was infused in place of the cardioplegic solution, and cardiac arrest was not induced. No significant differences were observed between the groups infused with the K-H solution containing Ca concentrations of 0.6, 1.2, and 2.5 mmol/l in the percent recovery of aortic flow (82.1±2.9%, 80.6±2.0%, and 71.5±3.7% (mean±SEM) respectively) or in the recovery of other indices of cardiac function, or in CK leakage. There were also no significant differences in the recovery of cardiac function and CK leakage between these groups and the control group. In the Ca 0.1 mmol/l group, however, the characteristic Ca paradox was observed. These findings suggest that if the Ca concentration in a cardioplegic solution is higher than 0.6 mmol/l during continuous cardioplegia, excellent cardioprotective effects will be achieved.     

Metastatic Behavior and Tumorigenicity of a Human Melanoma Cell Line (MM-RU) after Injection into Nude Mice

The ability of the human amelanotic melanoma cell line MM-RU to produce experimental metastases and to grow tumors at subcutaneous inoculation sites in 4-week-old nude mice was examined. After i.v. inoculation of 10⁶ cells, all injected mice (n=21) developed consistent numbers of metastatic pulmonary colonies within 32 days. The coefficients of variation for the number of colonies were between 17%–23% in three independent experiments. Survival time after i.v. inoculation was 63 ± 7 days (mean ± SD) (n=20). Within 20 days, subcutaneous inoculation of 5 × 10⁶ cells resulted in tumor growths of 13 ± 3 mm (mean ± SD) at the inoculation sites in all nude mice (n=12). The MM-RU cell line seems to be a simple, fast vehicle for testing the effect of melanoma growth modulators on experimental pulmonary metastases as well as on subcutaneously growing melanoma.     

Discrete breakpoint mapping and shortest region of overlap of chromosome arm 1q gain and 1p loss in human hepatocellular carcinoma detected by semiquantitative microsatellite analysis

Recurrent chromosomal gain at 1q is one of the most common features of human hepatocellular carcinoma (HCC), but how the gain at 1q contributes to hepatocarcinogenesis is still unclear. To identify the target genes, precise determination of the shortest region of overlap (SRO) and of breakpoints is necessary. Similarly, the role of loss at 1p, which is also a major cytogenetic aberration in HCC, needs to be determined. Fifty HCCs were examined with the aid of 59 microsatellite markers distributed throughout both arms of chromosome 1. To detect allelic gain effectively, the cutoff value of the allelic imbalance index was set at 0.70. Alleles showing imbalance were subjected to multiplex PCR, using a retained allele as an internal control, to determine whether the imbalance was the result of chromosomal gain or loss. The SRO of the gains was defined as D1S2878-D1S2619 (1q23.-q25.3, 16.9 Mb), which involved 36 cases (72%). Gains in the number of copies of certain oncogenes within this region seemed to be critical for the pathogenesis of HCC. In contrast, the centromeric breakpoints of these gains varied, but they tended to occur mainly in the pericentromeric region (26 of 50 cases, 52%). Rearrangement of specific genes associated with the gains is unlikely. On the other hand, the SRO of deletion was defined as D1S2893-D1S450 (1p36.32-p36.22, 5.1 Mb). Four known putative tumor-suppressor genes (TP73, RIZ1, NBL1/DAN, and CDKN2C) were outside the SRO, suggesting the presence of other candidate genes with critical roles in hepatocarcinogenesis.     

WIDESPREAD ECZEMA VACCINATUM ACQUIRED BY CONTACTS A Report of an Autopsy Case

A4-moth-old male infant predisposed to allergic dermatitis acquired widespread eczema vaccinatum by contacts with a recently vaccinated sibling. He died of acute purulent peritonitis following a perforation of multiple duodenal ulcers. Fluorescence immunocytochemical and electron microscopic studies on the skin lesions revealed the presence of viral antigens and numerous virus particles compatible morphologically with those of the mature form from the same batch of smallpox vaccine given to the sibling. A large number of virus particles in the developmental form were also predominantly scattered in the cytoplasm of cells at the stratum malpighii of the epidermis as well as in neutrophils and macrophages in the skin lesions. The virus isolation from the skin lesions was done by using the HeLa cells and the human embryonic lung fibroblasts. No abnormal laboratory data were noted in immunoglobulins. On the basis of atrophy of the thymus and other lymphatic tissues and an appearance of large pyroninophilic cells in association with blastoid transformation, the authors discussed a possible participation of the disturbance of cellular immunity secondary to the virus infection in the development of the disease. ACTA PATH. JAP. 29 : 435–455, 1979.     

Identification of 16 novel mutations in the argininosuccinate synthetase gene and genotype-phenotype correlation in 38 classical citrullinemia patients

Classical citrullinemia (CTLN1), a rare autosomal recessive disorder, is caused by mutations of the argininosuccinate synthetase (ASS) gene, localized on chromosome 9q34.1. ASS functions as a rate-limiting enzyme in the urea cycle. Previously, we identified 32 mutations in the ASS gene of CTLN1 patients mainly in Japan and the United States, and to date 34 different mutations have been described in 50 families worldwide. In the present study, we report ASS mutations detected in 35 additional CTLN1 families from 11 countries. By analyzing the entire coding sequence and the intron-exon boundaries of the ASS gene using RT-PCR and/or genomic DNA-PCR, we have identified 16 novel mutations (two different 1-bp deletions, a 67-bp insertion, and 13 missense) and have detected 12 known mutations. Altogether, 50 different mutations (seven deletion, three splice site, one duplication, two nonsense, and 37 missense) in 85 CTLN1 families were identified. On the basis of primary sequence comparisons with the crystal structure of E. coli ASS protein, it may be concluded that any of the 37 missense mutations found at 30 different positions led to structural and functional impairments of the human ASS protein. It has been found that three mutations are particularly frequent: IVS6-2A>G in 23 families (Japan: 20 and Korea: three), G390R in 18 families (Turkey: six, U.S.: five, Spain: three, Israel: one, Austria: one, Canada: one, and Bolivia: one), and R304W in 10 families (Japan: nine and Turkey: one). Most mutations of the ASS gene are "private" and are distributed throughout the gene, except for exons 5 and 12-14. It seems that the clinical course of the patients with truncated mutations or the G390R mutation is early-onset/severe. The phenotype of the patients with certain missense mutations (G362V or W179R) is more late-onset/mild. Eight patients with R86H, A118T, R265H, or K310R mutations were adult/late-onset and four of them showed severe symptoms during pregnancy or postpartum. However, it is still difficult to prove the genotype-phenotype correlation, because many patients were compound heterozygotes (with two different mutations), lived in different environments at the time of diagnosis, and/or had several treatment regimes or various knowledge of the disease.     

Occlusion and subsequent re-canalization in early duodenal development of human embryos: integrated organogenesis and histogenesis through a possible epithelial-mesenchymal interaction

Histogenesis of the duodenum, especially changes in the epithelium in relation to temporal occlusion and re-canalization of the lumen, was investigated by light microscopy together with morphometric analysis, as well as by scanning and transmission electron microscopy of 133 externally normal human embryos ranging from Carnegie stage 12 to 23. A series of morphogenetic events passed the duodenum in a cranio-caudal (proximo-distal) wave like fashion during the period examined. They included: (1) a decrease in the caliber and area of the lumen, (2) ’occlusion’ of the lumen, (3) vacuole formation, (4) ’re-canalization’ and villi formation. The only exemption to this rule was that, in the upper part of the duodenum, the lumen was not obliterated in the embryos examined. Morphometric analyses revealed that both the area of the epithelium and the number of epithelial cells decreased during the ’occlusion’ phase. This result suggests that, unlike the classical view, epithelial cell proliferation does not play an important role in occluding the lumen, but the predominant morphogenetic event during this phase is convergence of the epithelial cells to elongate the duodenum. Apoptosis, contrary to some classical views, decreased during the ’re-canalization’ phase, and it appeared to be involved in the formation of the small lumens in the epithelial ’plug’ and in villi formation, but not in enlarging the secondary lumens. The secondary small lumens in the occluded lumen were frequently formed near the border between the central ’plug’ and peripheral basal cells on the basement membrane. This and other findings of concentric differentiation in both the epithelial and mesenchymal layers suggested a possible control mechanism by the epithelium-mesenchymal interaction on human duodenal morphogenesis and histogenesis. The present electron microscopic observations also provided details on the mechanisms involved in the enlargement of the secondary lumen and differentiation of villi. The implications of these findings to duodenal anomalies are also discussed. Accepted: 12 November 2001     

Clinical significance of a highly sensitive enzyme immunoassay of hepatitis B surface antigen using a novel electron spin resonance technique.

We developed a highly sensitive enzyme immunoassay (EIA), the p-AP/HHTIO method, that detects serum hepatitis B surface antigen (HBsAg) by measuring stabilized nitroxide radicals using a novel electron spin resonance technique [Matsuo et al. (1998) Free Radic Biol Med 25:929-935]. To demonstrate the clinical significance of this method and to reveal occult hepatitis B virus (HBV) infection in patients, we used the method to analyze serum samples of 30 patients with acute or fulminant hepatitis who were negative for HBsAg by standard EIA, and those of seven chronic HBV carriers who became negative for HBsAg during a follow-up period by standard EIA. We also examined serum HBV DNA by amplification of the HBV S gene, using the polymerase chain reaction (PCR) technique. The p-AP/HHTIO method showed that 9 of 20 (45%) patients with acute hepatitis and 2 of 10 (20%) with fulminant hepatitis were positive for HBsAg; PCR detected HBV DNA in these HBsAg-positive patients. Antibody against hepatitis B core antigen was detected in one patient with fulminant hepatitis. The p-AP/HHTIO method demonstrated prolonged seropositivity of HBsAg even after standard EIA showed a loss of HBsAg in all seven HBV carriers. Our p-AP/HHTIO method is useful for screening and diagnosing HBV infection in patients with liver diseases who are negative for conventional HBV-related serological markers.     

Genetic polymorphisms of orosomucoid and alpha-2-HS-glycoprotein in Thai,Sri Lankan and Paraguayan populations

The genetic polymorphism of orosomucoid (ORM) and alpha-2-HS-glycoprotein (AHSG) were studied in Thai, Sri Lankan and Paraguayan populations using isoelectric focusing. Gene frequencies in these populations were compared with those in other populations. Four new ORM variants were detected:ORM1 ^* 15 in Thai,ORM1 ^* 16 in Paraguayan,ORM2 ^* 21 andORM2 ^* 22 in Sri Lankan.     

Usefulness of continuous air tonometry for evaluation of splanchnic perfusion during cardiopulmonary bypass

Although gastric mucosal tonometry has been reported as a useful method to assess splanchnic perfusion during cardiovascular surgery, the conventional discontinuous method of tonometry (saline tonometry) was cumbersome and prone to systematic errors. A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 10 minutes) measurement of gastric regional CO2 (PrCO2) and may be more suitable as a monitoring system in cardiac patients. We evaluated the usefulness of continuous air tonometry as a marker of splanchnic perfusion during cardiopulmonary bypass (CPB). In 19 patients (53-79 years, mean 63 years) who underwent cardiovascular surgery under standard CPB with mild hypothermia (32 degrees C) from January 2001 to May 2002, the PrCO2 and calculated intramucosal pH (pHi) of gastric tonometry was monitored using Tonocap, and their relation to postoperative visceral organ function was evaluated. The pHi significantly increased after initiation of CPB from 7.32 +/- 0.07 to 7.43 +/- 0.10 (p < 0.05) and then consistently decreased in all patients to 7.39 +/- 0.09 at the end of CPB. The value of PrCO2 significantly (p < 0.01) correlated with the value of pHi. The lowest value of pHi during CPB was significantly related to blood urea nitrogen (r = -0.75, p < 0.05), serum creatinine (r = -0.78, p < 0.05), creatinine clearance (r = 0.68, p < 0.05) on postoperative day 1, and blood urea nitrogen (r = -0.84, p < 0.01) on day 3. In contrast, arterial blood lactate level, venous oxygen saturation, and routinely measured hemodynamics (e.g., pump flow, arterial pressure) during CPB were unrelated to the postoperative visceral organ function. These results suggest that continuous monitoring of gastric regional CO2 and pHi by air tonometry system is useful for the evaluation of splanchnic perfusion during CPB and may contribute to improve CPB technique by allowing the early detection of visceral malperfusion.     

Pituitary Folliculo-Stellate-Like Cells Stimulate Somatotroic Pituitary Tumor Growth in Nude Mice

A new cell line (TtT/GF) established from a murine pituitary thyrotropic tumor having characteristics similar to those of pituitary folliculo-stellate cell (FS cell) was implanted into nude mice together with cells from a rat pituitary somatotrophic tumor cell line (MtT/S) to determine whether the former enhances pituitary tumor growth. For as long as 2-3 mo after implantation, MtT/S cells implanted either alone or together with fibroblasts formed either no tumors or only very small tumors in the nude mice. In contrast all of the nude mice that had received MtT/S cells implanted together with TtT/GF cells developed large tumors. Furthermore, the mice bearing the MtT/S and TtT/GF implants showed a significantly higher body weight and serum growth hormone level than those bearing only MtT/S cells or a combination of MtT/S cells and fibroblasts. The TtT/GF cell line itself had no tumorigenicity during the experimental period. Therefore, the TtT/GF cell line as a model of FS cells enhanced pituitary endocrine cell tumor formation. Additionally, immunocytochemistry showed that TtT/GF cells positive for glial fibrillary acidic protein (GFAP) or S-100 protein were present in the parenchymatous tissue elements or connective tissue surrounding the tumor nests. In the parenchymatous tissue, the TtT/GF cells exhibited a stellate appearance and surrounded neighboring tumor cells with their long cell processes. These results suggest that TtT/GF cells can serve as a model for pituitary FS cells, and are capable of stimulating pituitary tumor growth either by modifying the microenvironment or producing growth factors.