Loss or Somatic Mutations of hMSH2 Occur in Hereditary Nonpolyposis Colorectal Cancers with hMSH2 Germline Mutations

Hereditary nonpolyposis colorectal cancer (HNPCC) is a major cancer susceptibility syndrome known to be caused by the inheritance of mutations in DNA mismatch repair genes, such as hMSH2, hMLH1, hPMS1 and hPMS2 . To investigate the role of genetic alterations of hMSH2 in HNPCC tumorigenesis, we analyzed 36 Japanese HNPCC kindreds as to hMSH2 germline mutations. Moreover, we also examined somatic mutations of hMSH2 or loss of heterozygosity at or near the hMSH2 locus in the tumors from the hMSH2 -related kindreds. Germline mutations were detected in five HNPCC kindreds (5/36, 14%). Among them, three were nonsense mutations, one was a frameshift mutation and the other was a mutation in an intron where the mutation affected splicing. Loss of heterozygosity in four and somatic mutations in one were detected among the eight tumors with hMSH2 germline mutations. All these alterations were only detected in genomic instability(+) tumors, i.e., not in genomic instability(-) ones, indicating that mutations of hMSH2 were responsible for at least some of the tumors with genomic instability. These data establish a basis for the presymptomatic diagnosis of HNPCC patients, and constitute further evidence that both DNA mismatch repair genes and tumor suppressor genes may share the same requirement, i.e., two hits are necessary to inactivate the gene function.     

Effect of replacing the aspartic acid/glutamic acid residues of bullfrog sialic acid binding lectin with asparagine/glutamine and arginine on the inhibition of cell proliferation in murine leukemia P388 cells

The sialic acid binding lectin from bullfrog oocytes (cSBL) is known to have anti-tumor activity. In a previous report, to elucidate the relationship between the net charge and anti-tumor activity of cSBL, we examined the effect of chemical modifications of cSBL with a water-soluble carbodiimide in the presence of various nucleophiles. The results suggested that the anti-tumor activity and internalization into tumor cells increased with an increase in the net charge of cSBL. However, in the chemically modified cSBL, a modification site was observed on average in two of the carboxyl groups of cSBL. To confirm these previous results and to determine which modified carboxyl group contributes to the increase in anti-tumor activity, we prepared mutants with substitutions of Asn/Gln and Arg at three acidic amino acid residues of cSBL and studied their anti-tumor activity and internalization efficiency. The results showed the enhancing effect of charge on anti-tumor activity and internalization, and suggested that the replacement of D24 and E88 of cSBL with arginine is more effective than that of E97. The double mutant D24RE88R showed comparable anti-tumor activity to the ethylenediamine-modified cSBL reported previously. The mutant was well-characterized as a pure cSBL derivative suitable for studying the mechanism of the anti-tumor action of cSBL.     

Chinese medicine induces neurite outgrowth in PC12 mutant cells incapable of differentiation

During continuous culture of neural PC12 cells, we obtained a drug-hypersensitive PC12 mutant cell that showed high stimulation of neurite outgrowth by various drugs. When several Chinese medicines such as shu-jing-huo-xie-tang and Wu-Ling-San were provided to these PC12 mutant cells, the frequency of nerve growth factor (NGF)-induced neurite outgrowth increased approximately 30-fold compared to NGF alone. Neurite outgrowth induced by NGF in PC12 cells is accompanied by sustained activation of mitogen-activated protein kinase (MAPK); however, these Chinese medicines did not induce MAPK activity. The findings thus indicate that certain Chinese medicines may induce neurite outgrowth by a novel mechanism which is distinct from the NGF-activated pathway in PC12 mutant cells.     

Cerebral hemodynamics and metabolism in patients with cerebral arteriovenous malformations: an evaluation using positron emission tomography scanning

OBJECT: The purpose of this study was to evaluate cerebral hemodynamic and metabolic features in patients with arteriovenous malformations (AVMs) by using positron emission tomography (PET) scanning. METHODS: Twenty-four patients with supratentorial cerebral AVMs participated in PET studies in which 15O inhalation steady-state methods were used. The authors recorded the values of regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), the regional oxygen extraction fraction (rOEF), and the regional cerebral metabolic rate of O2 (rCMRO2) at three designated regions of interest (ROIs) in each patient. These ROIs included perilesional (ROI-p), ipsilateral remote (ROI-i), and contralateral symmetrical (ROI-c) brain regions. To identify the factors that exert a direct effect on the hemodynamics of brains affected by AVM, we also separated the lesions according to their size and flow type shown on angiograms, and grouped the patients according to the presence or absence of progressive neurological deficits. We then compared the PET parameters at different ROIs in individual patients and evaluated the mean values obtained for all 24 patients according to AVM flow type and size, and the presence or absence of progressive neurological deficits. CONCLUSIONS: Overall, mean rCBV and rOEF values were significantly higher in ROI-p than in ROI-c (p = 0.00046 and p = 0.015, respectively). No significant differences were seen between the ROI-i and ROI-c with respect to rCBF, rCBV, and rOEF. Mean rCMRO2 values were similar in the three ROIs; however, the mean rCBF was significantly lower in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.019), large AVMs (p = 0.017), and progressive neurological deficits (p = 0.021). Furthermore, the mean rOEF values were significantly higher in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.005), large AVMs (p = 0.019), and progressive neurological deficits (p = 0.017). The PET studies revealed hemodynamic impairment characterized by decreased rCBF and increased rOEF and rCBV values in the ROI-p of patients with large, high-flow AVMs regardless of whether they exhibited progressive neurological deficits.     

Concentrative relationship between polymorphonuclear elastase and urinary trypsin inhibitor in amniotic fluid

In the amniotic fluid, urinary trypsin inhibitor (UTI) seems to inhibit polymorphonuclear elastase (PMNE) activity. The PMNE and UTI concentrations in normal amniotic fluid at 16–20 and 38–40 gestational weeks were measured. The PMNE concentration increased significantly at 38–40 weeks, whereas UTI concentration decreased significantly. According to concentrative relationships between both substances, PMNE may be activated more at the full term pregnancy. Since PMNE-induced tissue injury potentially causes degradation of amniotic collagen, the present result suggests that the quotient of PMNE and UTI concentrations is a reliable index to estimate the occurrence of rupture of the membranes. Received: May 1999 / Accepted: 11 January 2000     

A study of cerebral circulation following cervical sympathetic ganglion block]

Cerebral circulation following cervical epidural block or stellate ganglion block at the transverse process of the 6th cervical vertebra (C6-SGB) was evaluated by single photon emission computed tomography of inhaled Xenon-133. Cerebral blood flow before and 15 min after both blocks was measured in eight patients after cervical epidural block and ten patients after C6-SGB. Cerebral blood flow decreased slightly following cervical epidural block, but it was not a statistically significant difference. Cerebral blood flow following C6-SGB could be separated into two groups; in one it increased and in the other it decreased slightly. In conclusion, cerebral circulation is not influenced by cervical epidural block, but it is probably affected by C6-SGB. The manner in which C6-SGB increases cerebral blood flow seems that local anesthetics reached the superior cervical ganglion and block it. C6-SGB without superior cervical ganglion block does not influence cerebral circulation, and it only dilates extracranial vessels.     

Growth Hormone-Releasing Hormone (GHRH)-GH-Somatic Growth and Luteinizing Hormone (LH)RH-LH-Ovarian Axes in Adult Female Transgenic Mice Expressing Human GH Gene

We have examined alterations in the hypothalamo-pituitary GH-somatic growth axis and the hypothalamo-pituitary LH-ovarian axis in a line of transgenic ICR mice expressing human GH (hGH) under the influence of the whey acid protein promoter. Transgenic female mice weighed twice as much as control females and were infertile. The size of the anterior pituitary (AP) was that of the controls. In transgenic mice, acinar cells in the mammary and mandibular glands displayed hGH-immunoreactivity, and plasma hGH was detected by radioimmunoassay. In the medial basal hypothalamus (MBH) of transgenic females, the immunoreactive-GHRH level was decreased (P<0.01). There was a corresponding reduction in the number of GHRH-immunoreactive neurons in the arcuate nucleus (ARC) and in the immunostaining of GHRH nerve terminals in the median eminence. The level of somatostatin (SRIH) in the MBH was increased (P<0.05), and SRIH-immunoreactive neurons in the periventricular nucleus (PeV) were increased in size and number in transgenic mice. The MBH level of LHRH in transgenic animals was greater (P<0.01) than in controls, although there was no apparent difference in the number of LHRH-immunoreactive neurons or in LHRH level in the preoptic area. There are fewer SRIH- and LHRH-immunoreactive neurons in the ARC in transgenic mice. Cells in the AP for GH, PRL, and LH were fewer in transgenic mice. The ovary suffered disturbance of follicular development and of corpora lutea formation.