Evaluation of genetic counselling: recall of information, post-counselling reproduction, and attitude of the counsellees

Of the families who had received genetic counselling between 1972 and 1981, 791 replied to a questionnaire which covered recall of information, post-counselling reproduction and attitudes towards counselling and prenatal diagnosis. Eighty percent had adequate knowledge of mode of inheritance and 74% of recurrence risk. Knowledge of mode of inheritance was poorest in multifactorial transmission (63%) and knowledge of recurrence risk in X-chromosomal disorders (61%). Forty-five per cent of the families had started a pregnancy after the counselling. 25%). Early lethality of the disorder and feasibility of a prenatal study contributed to positive reproductive decisions. Nine per cent of the children born after the counselling were affected by the disorder in question. The observed risks tended to match well with the expected ones. Sixty-two per cent of the respondents felt that the counselling had had a great or moderate impact on their reproductive plans. Forty-two per cent expressed a wish to hear the counsellor's opinion in addition to the facts. This was more common when the disorder was severe. Although most couples (53%) wished to have a prenatal study, if feasible, and abort an affected foetus, 16% were against abortion in such a case and 31% wished to have the study but were ambiguous about an abortion.     

Different Ca2+ dynamics between isolated hippocampal pyramidal cells and dentate granule cells

The hippocampal formation contains a variety of neuronal types. The principal neurons are granule cells in the dentate gyrus and pyramidal cells in Ammon's horn. These two neuron types show distinct cell morphology and display a different vulnerability to ischemic injury or various neurotoxins. In order to illustrate the difference in the pathophysiological properties of these neurons, we established a method for separately culturing granule cells and pyramidal cells. They were prepared from the dentate gyrus and Ammon's horn of 3-day-old Wistar rat pups and maintained for 7–9 days in culture. After transient exposure to N-methyl-D-aspartate or glutamate, both the cultured neuron populations displayed somatic Ca²⁺ transients with similar amplitudes, but the subsequent recovery to baseline was about twice as fast in granule cells than in pyramidal cells. Similar results were obtained for K⁺ depolarization-induced Ca²⁺ elevation, suggesting that the relatively rapid Ca²⁺ clearance in granule cells is independent of Ca²⁺ influx pathways. The present study provides the first evidence for a difference in Ca²⁺ dynamics and homeostasis between granule and pyramidal cells and may represent a cellular basis for the differential vulnerability of hippocampal neurons.     

Application of personal computer to an analysis of smallde novo chromosomal insertion: A case ofde novo 3q2 trisomy with ins(8;3)

To identify the origin of a small inserted segment in ade novo 8p+ chromosome, an originally programmed computerized data-base for chromosomal aberration syndromes was utilized. The system selected 3q2 trisomy and 10q2 trisomy as candidates. As a result of a careful comparison of several high-resolution banding patterns among chromosomes 3, 10 and the inserted segment, her karyotype was disignated as: 46,XX,–8,+der(8), inv ins(8;3)(p21.1;q26.32q24)de novo. A small segment from 3q24 to 3q26.32 was trisomic, and invertedly inserted into the short arm of chromosome 8. This computerized database was considered to be useful for analyses of the smallde novo inserted chromosomal segment.     

HLA-DP and susceptibility to insulin-dependent diabetes mellitus in Japanese

ABSTRACT: Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM.     

Mutation analysis of two Japanese patients with Fanconi-Bickel syndrome

Fanconi-Bickel syndrome (FBS), or glycogen storage disease type XI, is a rare autosomal recessive disorder characterized by hepatorenal glycogen accumulation, Fanconi nephropathy, and impaired utilization of glucose and galactose. Recently, this disease was elucidated to link mutations in the glucose transporter 2 (GLUT2) gene. Only three mutations in three FBS families have been reported. Therefore, it is important to elucidate mutations in the GLUT2 gene in FBS by answering the question of whether the syndrome is a single gene disease. In this report, we describe two patients in two unrelated families clinically diagnosed with FBS. No mutation in the entire protein coding region of the GLUT2 gene was detected in patient 1, which suggested that no mutation existed in the GLUT 2 gene, or that some mutations had affected the expression of the GLUT 2 gene. In patient 2, a novel homozygous nonsense mutation (W420X, Trp at codon 420 to stop codon) was detected. These results support the correlation between GLTU2 gene mutation and FBS syndrome. However, many patients must be analyzed to determine whether other genes are involved in FBS. Received: July 16, 1999 / Accepted: September 3, 1999     

Blood Flow and Leukocyte Adhesiveness Are Reduced in the Microcirculation of a Peritoneal Disseminated Colon Carcinoma

Dynamic behavior of leukocytes in the microcirculation of solid tumor tissue was visualized using a fluorescent labeling technique combined with the use of a real-time confocal laser-scanning microscope (CLSM) system. Colon tumor cells (RCN-9) were inoculated into the peritoneal cavity of male Fischer 344 rats. Tumor-free rats were similarly injected with physiological saline (intraperitoneally). Ten days after tumor inoculation, the mesentery was exteriorized and subjected to vital microscopic observation under the CLSM system. Leukocytes were labeled with rhodamine 6G (100 g kg^–1, intravenously), and their behavior within the microvessels (10–30 m in diameter) was analyzed both in the solid tumor tissues and the normal mesentery. Wall shear rate was calculated from the measured values of vessel diameter and erythrocyte flow velocity. In tumor microvasculature of tumor-bearing rats, the centerline erythrocyte velocity (0.73 ± 0.58 mm s^–1, mean±standard deviation) and wall shear rate (210 ± 151 s^–1 were significantly lower than those of the tumor-free rats (1.27 ± 0.83 mm s^–, 344 ± 236 s^–1, respectively). Despite such reduced flow conditions, flux of the rolling leukocytes as well as density of the adhered leukocytes both decreased significantly in tumor microvasculature as compared with normal controls. The methods developed in this work show promise in improving our understanding of tumor biology and pathophysiology. © 1998 Biomedical Engineering Society. PAC98: 8722Fy, 8745Hw, 8745Ft, 8764-t, 4262Be     

Role of fibronectin-stimulated tumor cell migration in glioma invasion in vivo: clinical significance of fibronectin and fibronectin receptor expressed in human glioma tissues

In order to clarify the role of fibronectin in glioma invasion in vivo, we analyzed the relationship between fibronectin-stimulated cell migration and adhesion in 14 primary glioma cells and the expression of fibronectin and the fibronectin receptor in the corresponding tumor tissues. The tumors comprised nine glioblastomas (GB) and five anaplastic gliomas (AG) consisting of two astrocytomas, two oligoastrocytomas and one ependymoma. All glioma cells tested in the primary cell culture were found to migrate to fibronectin in a dose-dependent manner. The extent of cell migration to fibronectin was not significantly different for the GB and AG groups. On the other hand, cell adhesion to fibronectin in the AG was much stronger than that in the GB group. Immunohistochemistry demonstrated that fibronectin positively stained in the extra-cellular matrix (ECM) in eight cases and that the fibronectin receptor was positive in tumor cell membranes in 10 cases. In addition, cellular fibronectin isoforms containing ED-A and ED-B sequences were found to be immunolocalized in the tumor cells and the ECM of GB. These isoforms were also specifically expressed in tumor vessels within tumor tissues, but not in those within normal brain tissues. Cell migration tended to be expressed more strongly by glioma cells derived from tumor tissues in which fibronectin was posi-tively immunolocalized in the ECM than from tissues with negative fibronectin in the ECM. Four glioma cells derived from GB whose tumor cells did not positively stain for fibronectin receptors migrated much less extensively to fibronectin than other glioma cells whose tissues showed positive staining for the fibronectin receptor. Of these four GB, two had loss of heterozygosity in the locus of fibronectin receptor b1 gene. These results suggest that fibronectin deposited in the extracellular matrix of tumors, which can be derived from both plasma and the tumor cell itself, strongly promotes the migration of glioma cells, and that expression of the fibronectin receptor may play a critical role in the biological behavior of the tumor cells, particularly in fibronectin-stimulated cell migration in vivo.© Kluwer Academic Publishers 1998     

Identification of ligand recognition sites in heat-stable enterotoxin receptor, membrane-associated guanylyl cyclase C by site-directed mutational analysis.

Guanylyl cyclase C (STaR), a receptor protein for heat-stable enterotoxin (STa) elaborated by Escherichia coli, is associated with and spans the plasma membrane of mammalian intestinal cells. The extracellular domain functions in the binding of STa and the association of each domain to an oligomeric form. Two amino acid residues, Arg-136 and Asp-347, were identified as the residues binding to STa in the extracellular domain of pig STaR by site-directed mutagenesis and analysis of expression on 293T cells. Replacement of these residues by other amino acid residues resulted in the loss of binding of pig STaR to STa, and as a result, STa-induced guanylyl cyclase activity was eliminated. Furthermore, mutation in a region (from Asp-347 to Val-401) which is close to the transmembrane domain caused a significant reduction in both STa-binding activity and guanylyl cyclase catalytic activity. These results suggest that the region adjacent to the transmembrane domain plays an important role in facilitating a favorable conformation of STaR for STa binding.