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 degrees 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.

Decrease of tissue angiotensin I-converting enzyme activity upon feeding sour milk in spontaneously hypertensive rats

Blood pressure increases were inhibited by feeding a diet containing sour milk fermented by a starter containing Lactobacillus helveticus and Saccharomyces cerevisiae to spontaneously hypertensive rats. In rats fed with the sour milk, the angiotensin I-converting enzyme activity of the aorta was significantly lower than that of rats fed with the control commercial diet.

The Japan Society of Human Genetics Award Lecture. Application of DNA markers to clinical genetics

DNA technology using DNA sequence polymorphisms has brought a new system to the fields of medicine and forensic science, especially for the studies of genetic diseases and tumor suppressor genes, and for identification of individuals for forensic purpose. Linkage analysis based on segregation of polymorphic alleles in affected families has contributed to identification of many genetic disease. We isolated a large number of polymorphic DNA markers, called VNTR (variable number of tandem repeat) markers and identified the APC gene that is responsible for familial adenomatous polyposis (FAP) by means of a so-called "positional cloning" and characterized germline and somatic mutations of the APC gene in colorectal cancer patients. In addition, we have applied genetic information during colorectal carcinogenesis to sensitive diagnosis of lymph-node metastasis of colorectal cancer.

Upregulation of apolipoprotein A-IV gene expression in residual ileum after massive small bowel resection requires the biliary secretion in rats

Small bowel resection results in adaptation of residual intestine, but little is known about the postresectional response of apolipoproteins synthesized mainly in the small intestine. We have investigated the postresectional response of apolipoprotein A-1 and A-IV gene expression in residual ileum and assessed the mechanism of response, particularly the role of biliary secretion. Time course of changes in apolipoprotein A-1 and A-IV mRNA levels was examined by Northern blotting in the residual terminal ileum for 24 hr after 85% jejunoileal resection in fasted rats. Localization of these mRNAs was studied using in situ hybridization histochemistry. Effect of biliary diversion on the postresectional response of mRNAs and proteins was estimated by Northern blotting and immunoblotting, respectively. Apolipoprotein A-IV mRNA began increasing at 1 hr postresection, achieved a maximum by 12 hr (5-fold increase) and remained stable to 24 hr, while apolipoprotein A-1 mRNA did not change. Apolipoprotein A-IV mRNA accumulated predominantly in the upper part of ileal villi and increased its intensity postresection, and apolipoprotein A-1 mRNA was detected in the villus base to tip. The postresectional increase in apolipoprotein A-IV MRNA and protein was completely abolished by concurrent biliary diversion. The results suggest that the enterocytes in the ileal villi rapidly adapt to massive small bowel resection by increase in apolipoprotein A-IV gene expression which is mediated by biliary constituents but not luminal nutrients.

Isolation of a cosmid clone corresponding to an inv(21) breakpoint of a patient with transient abnormal myelopoiesis

Transient abnormal myelopoiesis (TAM) is a leukemoid reaction occurring occasionally on Down syndrome (DS) newborn infants. It has been hypothesized that "disomic homozygosity" in 21-trisomic cells plays an important role in the genesis of TAM, and the putative TAM gene was suggested to be mapped at a 21q11 region. We encountered a DS-associated TAM infant with a 47,XY,inv(21)(q11.1q22.13),+inv(21)(q11.1q22.13) karyotype. On the basis of another presumption that in this patient the putative TAM gene is disrupted by the break, we tried to isolate a breakpoint DNA. FISH analysis with cosmid clones corresponding to various sequence-tagged-site (STS) markers mapped at around 21q11.1-q11.2, we confirmed that the proximal breakpoint of the inv(21) was located between two STSs, G51E07 and D21S215, the latter locus being consistent with the previous tentative mapping. After construction of a cosmid contig encompassing between the two markers, we have isolated a cosmid clone corresponding to the proximal breakpoint of the inversion. This breakpoint was located near a previously identified duplicated region that is homologous to the sequence at 21q22.1. The isolated cosmid clone is useful for analysis of other TAM patients and for a search for a transcript at or flanking the breakpoint.

Sporothrix schenckii isolated from a cat in Japan

A yeast-like fungus isolated from a granulomatous and ulcerative skin lesion in a mongrel cat was mycologically examined. The isolate was identified as Sporothrix schenckii from the morphological findings and its pathogenicity in a mouse, confirming the first case of feline sporotrichosis in Japan. Fortunately, no transmission to humans occurred in this case, however the risk of humans contracting Sporothrix schenckii infection increases with the increase in the number of animals with sporotrichosis. Consequently when handling such animals protective clothing such as gloves should be worn to reduce the risk of transmission of the fungus through open wounds.

Dynamics of bovine glial fibrillary acidic protein phosphorylation

Recently, the dynamic features of the intermediate filaments (IF) have been revealed. The effect of phosphorylation on the dynamics of bovine glial fibrillary acidic protein (GFAP), the astroglial IF, was studied in vitro with fluorescently labeled GFAP. Soluble GFAP in low ionic strength buffer was rapidly and fully phosphorylated to be used as phosphorylated GFAP. Assembly of GFAP was observed to be inhibited in proportion to the extent of phosphorylation by mixing phosphorylated and non-phosphorylated GFAP at various ratios, and phosphorylated GFAP could not be assembled with non-phosphorylated GFAP into filaments at all. Furthermore, the subunit exchange was suppressed in proportion to the extent of phosphorylation. Phosphorylation affects the dynamic equilibrium of GFAP, and contributes to breaking down GFAP frameworks in mitotic glial cells.

Tob, a novel protein that interacts with p185erbB2, is associated with anti-proliferative activity

We have molecularly cloned a cDNA for a novel protein termed Tob (Transducer of ErbB-2) that interacts with the c-erbB-2 gene product p185erbB2. Nucleotide sequencing reveals that the Tob protein is a 45 kDa protein that does not contain either SH2 (Src Homology 2) or SH3 domain but is homologous to the previously characterized anti-proliferative gene product BTG-1 at its amino-terminal half. The carboxyl-terminal half of Tob is characterized by the presence of a sequence rich in proline and glutamine and shows no homology to known proteins. Like BTG-1, exogenously expressed Tob is able to suppress growth of NIH3T3 cells, but the growth suppression is hampered by the presence of kinase-active p185erbB2. By using the GST-Tob protein that contains either full length or amino-terminal half of Tob, we show that the carboxyl-terminal half of Tob is relevant to its interaction with p185erbB2. Furthermore, we could co-immunoprecipitate the Tob protein with anti-ErbB-2 antibody, and reciprocally the p185erbB2 with anti-Tob antibodies. These data suggest that p185erbB2 negatively regulates the Tob-mediated anti-proliferative pathway through its interaction with Tob, resulting possibly in growth stimulation by p185erbB2. Finally, expression of the Tob mRNA is observed in various cell types and is not correlated with expression of c-erbB-2, suggesting that other receptor-type protein-tyrosine kinases are also involved in the Tob-mediated regulation of cell growth.

Molecular cloning and mapping of a human cDNA for cytosolic malate dehydrogenase (MDH1)

We have isolated a human cDNA encoding a protein of 334 amino acids that shows 96% identity in amino acid sequence to murine cytosolic malate dehydrogenase. Heart and skeletal muscle expressed this gene most highly among the adult human tissues examined by Northern blot analysis. By fluorescence in situ hybridization, we determined its chromosomal location to be 2p15.

Cloning and mapping of a novel human cDNA homologous to DROER, the enhancer of the Drosophila melanogaster rudimentary gene

We have isolated a novel human cDNA clone that encodes a protein with 80% identity in amino acid sequence to DROER, the enhancer of the rudimentary gene in Drosophila melanogaster. The rudimentary gene product is thought to have significant enzymatic functions in the pyrimidine metabolic pathway, as well as a critical role in development of the wings. The human cDNA, termed ERH, consists of 797 nucleotides, which include an open reading frame of 312 nucleotides encoding 104 amino acids. The ERH gene was expressed in all normal human tissues examined. We assigned the ERH gene locus to chromosomal band 7q34 by fluorescence in situ hybridization.

Distribution of Ca2+/calmodulin-dependent protein kinase kinase alpha in the rat central nervous system: an immunohistochemical study

Ca2+/calmodulin-dependent protein kinase IV (CaM-kinase IV) is activated by CaM-kinase IV kinase. We provided a rabbit antiserum against 20 amino acid residues at the carboxyl-terminal end of CaM-kinase IV kinase, and examined regional and intracellular distribution of CaM-kinase IV kinase immunohistochemically in the central nervous system of the rat by light and electron microscopy. The immunoreactivity was found in cellular nuclei of virtually all neurons. However, the immunoreactivity was weak in the nuclei of the granule cells in the cerebellar cortex, although the nuclei of the granule cells were reported to contain high CaM-kinase IV activity. Thus, it was suggested that other types of CaM-kinase IV kinase might exist in the cerebellum, and the present CaM-kinase IV kinase was named as CaM-kinase kinase alpha.

Progesterone inhibits superoxide radical production by mononuclear phagocytes in pseudopregnant rats

This study investigated the changes in superoxide radical production by mononuclear phagocytes in the corpus luteum (CL) during pseudopregnancy in rats. Activity of superoxide radical production was determined by the conversion of nitro blue tetrazolium (NBT) to blue formazan deposit. Rats received 10 mg NBT via the abdominal aorta on day 3, 7, or 13 of pseudopregnancy and were autopsied 1 min later to prepare the histological sections. The cells with blue formazan deposits (NBT-positive cells) in the CL were scarce on days 3 and 7 of pseudopregnancy and significantly increased on day 13 of pseudo-pregnancy. On the other hand, simultaneous administration of 100 micrograms phorbol 12-myristate 13-acetate, which activates mononuclear phagocytes to produce superoxide radical, significantly increased the numbers of NBT-positive cells in the CL on day 7 of pseudopregnancy, but not in the CL on day 3 or 13 of pseudopregnancy. To study the possibility that superoxide radical production by mononuclear phagocytes is inhibited by progesterone on day 7 of pseudopregnancy, peritoneal mononuclear phagocytes prepared on day 7 or 13 of pseudopregnancy were preincubated with 10, 50, or 100 ng/ml progesterone for 6 h and then stimulated with phorbol 12-myristate 13-acetate. Superoxide radical production was measured by the cytochrome c reduction method. One hundred nanograms per ml progesterone significantly inhibited superoxide radical production by mononuclear phagocytes, and this inhibitory effect of progesterone was significantly blocked by the simultaneous addition of RU486 (10(-7) M). These results suggested that progesterone inhibited superoxide radical production by the mononuclear phagocytes in the CL during midpseudopregnancy in rats.

Mutational analysis of mismatch repair genes, hMLH1 and hMSH2, in sporadic endometrial carcinomas with microsatellite instability

Microsatellite instability, monitored by replication error (RER), has been observed in both sporadic and hereditary types of endometrial carcinoma. In the hereditary tumors, this instability is considered to be caused by a germline defect in the DNA mismatch-repair system. We previously reported that nearly one-quarter of sporadic endometrial carcinomas examined revealed an RER-positive phenotype at multiple microsatellite loci. To investigate the role of genetic alterations of DNA mismatch-repair genes in sporadic endometrial carcinomas, we screened 18 RER(+) endometrial carcinomas for mutations of hMLH1 and hMSH2. Although we found no germline mutations, we detected two somatic mutations of hMLH1 in a single endometrial cancer; these two mutations had occurred on different alleles, suggesting that two separate mutational events had affected both copies of hMLH1 in this particular tumor. These data implied that mutations of hMLH1 or hMSH2 play limited roles in the development of sporadic endometrial carcinomas, and that the tumors with genetic instability might have alterations of other mismatch-repair genes, such as hPMS1 and hPMS2, or of unknown genes related to the mismatch-repair system.

Adenosine and propentofylline inhibit the proliferation of cultured microglial cells

Propentofylline is a xanthine derivative that has been known to protec t neurons against ischemia-induced damage. To assess its neuroprotective mechanisms, we examined the effect of propentofylline on microglial proliferation that is thought to play an important role in neuronal damage. We determined the proliferation of microglia cultured from neonatal rat brains by measuring [3H]thymidine update. Propentofylline inhibited microglial proliferation in a dose dependent manner; EC50 was about 3 mu M. Similar results were observed with 2-chloroadenosine (agonist for A1 and A2 adenosine receptors) and 2-chloro-N6-cyclopentyladenosine (A1 receptor agonist) but not with 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethyl-carboxamidoadenosine hydrochloride (A2 receptor agonist). However, 8-cyclopentyl-1,3-dipropylxathine (A1 receptor antagonist) could not reverse the inhibitory effect of propentofylline. Our results suggest that the neuroprotection by propentofylline is, as least in part, due to the direct effect of the drug on microglia and that the drug inhibits the proliferation via a certain mechanism not directly mediated by adenosine receptors.

Insulin-like growth factor binding protein-3 inhibits gonadotropin-induced ovulation, oocyte maturation, and steroidogenesis in rabbit ovary

The effects of insulin-like growth factor binding proteins (IGFBPs) on human CG (hCG)-induced oocyte maturation, ovulation, steroidogenesis, and intrafollicular plasminogen activator (PA) activity were investigated in rabbit ovaries perfused in vitro. The addition of IGFBP-3, but not IGFBP-1, to the perfusate dose dependently inhibited hCG-induced ovulation, whereas ovulation failed to occur in any ovaries perfused with medium or IGFBP-3 alone. IGFBP-3 (100 ng/ml) significantly inhibited the resumption of meiosis in ovulated ova and follicular oocytes in hCG-treated ovaries, as well as the hCG-stimulated production of estradiol (E2), but not progesterone, by the perfused ovaries. Intrafollicular PA activity increased significantly within 1 h after exposure to hCG, reaching a maximum at 4 h; IGFBP-3 significantly inhibited hCG-stimulated intrafollicular PA activity. The blockade of hCG-induced ovulation by IGFBP-3 correlated with the reduction in intrafollicular PA activity. Treatment with hCG induced a 2.5-fold increase in intrafollicular IGF-I messenger RNA levels at 4 h. Although ovulation failed to occur in ovaries treated with IGF-I (100 ng/ml) in the absence of gonadotropin, IGF-I significantly increased the mean diameter of preovulatory follicles and stimulated the resumption of meiosis in follicular oocytes. These effects of IGF-I on follicular growth and oocyte maturation were significantly inhibited by IGFBP-3 (100 ng/ml). Furthermore, IGFBP-3 significantly inhibited the IGF-I-stimulated production of E2. In conclusion, IGFBP-3, but not IGFBP-1, blocked the stimulatory effects of hCG in the ovulatory process. These findings suggest that IGFBP-3 may contribute to the regulation of intrafollicular PA activity during follicular development and ovulation evoked by gonadotropin exposure, at least in part, via neutralizing endogenously produced IGF-I.

Effect of in vitro and in vivo administration of dexamethasone on rat macrophage functions: comparison between alveolar and peritoneal macrophages

Resident alveolar macrophages (AMs) and peritoneal macrophages (PMs), though they originate from common precursor cells, differ morphologically and functionally. The two types of macrophages residing in different tissues may respond differently to glucocorticoids. In the present study, we compared the effects of a synthetic glucocorticoid, dexamethasone (Dex), on rat AMs and PMs with regard to their phagocytic activity and tumour necrosis factor-alpha (TNF-alpha) releasability. In vitro exposure of the macrophages to Dex caused the depression of phagocytic activity of AMs but not of PMs. In contrast, TNF-alpha releasability was depressed in the both types of macrophages, and no difference was found between AMs and PMs in their susceptibility to TNF-alpha regulation by Dex. When Dex was administered subcutaneously into rats, phagocytic activity was severely depressed in AMs but not in PMs. On the other hand, TNF-alpha releasability was depressed both in AMs and PMs by the in vivo Dex administration. The depression in PMs, however, was transitory and less severe than that in AMs. These results suggest that alveolar macrophages and peritoneal macrophages differ intrinsically in responses to glucocorticoid, and that the cell location and the cell's microenvironment can also modulate the effects of glucocorticoid on macrophage functions.

Oxygenation in fetal lambs supported by extrauterine right atrium to artery extracorporeal membrane oxygenation

OBJECTIVE

Our purpose was to determine the adequacy of oxygenation, particularly cranial and cardiac oxygenation, in exteriorized fetal lambs on right atrium to artery extracorporeal membrane oxygenation.

STUDY DESIGN

Thirteen fetal lambs were placed on right atrium to artery extracorporeal membrane oxygenation between the gestational ages of 113 and 133 days. Various PO2 and oxygen saturation (SO2) values were obtained by varying the oxygen concentrations at the oxygenator membrane. Blood gases, pH, and SO2 were observed on samples taken before and after membrane oxygenation from the left ventricle and through the cranial carotid arterial catheter. These were compared with control values obtained before the cessation of umbilical circulation. Fetal coronary oxygenation was represented by left ventricle PO2 and SO2 and cranial oxygen by carotid artery PO2 and SO2.

RESULTS

We classified oxygen saturation as low, medium, and high on the basis of the level of postmembrane SO2. Carotid artery cranial oxygenation in the low SO2 group was equivalent to control values, but that in the medium and high SO2 groups was significantly higher than in the control group. Left ventricle oxygenation was consistently lower than cranial oxygenation in any SO2 group. In the low group left ventricle oxygenation was significantly lower than the control values.

CONCLUSIONS

Right atrium to artery extracorporeal membrane oxygenation appears sufficient to oxygenate the fetal cranial circulation but may be inadequate for the efficient distribution of oxygenated blood into the left ventricle and thus the coronary circulation.

[Evaluation of a nationwide surveillance system for Kawasaki disease over an eleven-year period from 1984]

OBJECTIVE

The Japan Kawasaki Disease Research Committee has conducted a surveillance of Kawasaki disease in order to monitor changes in incidence continually, and to provide timely incidence data to the hospitals and related organizations. This study aims at clarifying the 11-year time trend between 1984 and 1995 of the incidence of Kawasaki disease in Japan and evaluating the validity of the surveillance system.

METHODS

Incidence data were obtained from 143 monitor hospitals throughout Japan with a postcard notification form, which included the number of patients with Kawasaki disease by sex for each of three 10-day periods every month.

RESULTS

1. The total number of patients thus reported in the 11-year period by the 143 facilities was 21,406. 2. After experiencing the two major outbreaks observed in 1984 and 1985, no abnormal increase has been seen for a least 8 1/2 years. 3. The changes in the time trend of the incidence from the surveillance data was almost identical to those of the nationwide surveys, indicating the high validity of the surveillance system for timely estimation of an abnormal increase in incidence. 4. Because about one-third of the total number of the patients reported by the nationwide surveys come from only about 9% of the total number of hospitals included in the nationwide survey, efficiency in data collection without serious distortion was confirmed for the surveillance system. 5. The estimated number of patients in 1993 and 1994 calculated from the ratio of the numbers of patients between the surveillance and nationwide surveys was 5700 in 1993 and 6000 in 1994. The average yearly incidence rates per 100,000 children aged 0-4 years was 90.

CONCLUSION

From the above results it is recommended that the surveillance system be continued in order to provide timely data on changes in the incidence of Kawasaki disease in Japan. It appears that the methods of data collection adopted in this system is applicable to the surveillance of other diseases.

Augmentation of antitumor immunity using genetically M-CSF-expressing L1210 cells

Macrophage colony-stimulating factor (M-CSF) enhances tumoricidal activities of macrophages. We transduced human M-CSF cDNA into the mouse lymphoid cell line, L1210, and examined the antitumor effect of the locally expressed M-CSF. Mice injected with the M-CSF-producing subline showed improved survival in comparison with the mock-transfected cell line or parental cell line plus M-CSF administration (20 microg/kg for 3 days) at inoculated cell numbers of 10(2) or 5 x 10(3). The survival rate at 50 days after injection of 10(6) high M-CSF-expressing cells was 80%, significantly higher than that after injection of the mock-transfected cells, which killed all the mice by day 23. The survival rate appeared to depend on the amount of M-CSF produced. Moreover, all surviving mice after intravenous injection of the M-CSF-expressing sublines were rechallenged with 10(6) parental L1210 cells at day 50, and all survived up to day 100, demonstrating that M-CSF-expressing cells induced immune protection against the parental cells. The same improvement of survival was observed in mouse M-CSF-expressing cell lines. These observations imply that M-CSF cDNA is a candidate gene for use in gene therapy in leukemia.

Adult onset of the Dandy-Walker syndrome

We describe a case of adult onset Dandy-Walker syndrome. A 35-year-old woman presented with symptoms of increased intracranial pressure and cerebellar signs. After excision of the cyst wall of the posterior fossa. The patient recovered completely. The role of magnetic resonance imaging in establishing the diagnosis and following the course of operation are emphasized. Possible pathophysiological mechanisms involved in the late appearance of the clinical symptoms and the treatment of this anomaly are discussed.