Current spread in the smooth muscle of the guinea-pig vas deferens

1. The membrane polarization in response to intracellular stimulation and external stimulation, the junction potentials evoked by nerve and field stimulation and the spontaneous junction potentials were studied in the guinea-pig vas deferens.

2. The responses to intracellular stimulation differed from those to external stimulation applied through a large electrode in the following ways: short time constant of the electrotonic potential; linearity of current—voltage relation; all-or-none spike only in a small proportion of the cells; high critical firing level; short latency; weak tendency for repetitive activity during depolarization; and sharp spatial decay of the response.

3. The difference between intracellular and external stimulation could be explained by differences in current distribution in the tissue, if many muscle fibres were aggregated in functional bundles, with three-dimensional cell-to-cell connexions, so that the membrane near an intracellular stimulating electrode was shunted by a large area of surrounding membrane.

4. The time course of the junction potentials depended on the manner by which they were produced. The junction potential evoked by hypogastric nerve stimulation was recorded in every cell with almost the same amplitude. The spontaneous junction potential decayed very sharply with distance and the time course of the falling phase was about 10 times faster than that of the evoked junction potential.

The difference between the time course of the junction potentials was also explained by the difference in current distribution in the tissue.

     

Detection of allelic imbalance in the gene expression of <Emphasis Type="Italic">hMSH2</Emphasis> or <Emphasis Type="Italic">RB1</Emphasis> in lymphocytes from pedigrees of hereditary,nonpolyposis, colorectal cancer and retinoblastoma by an RNA difference plot

A number of phenotypes in hereditary disorders or common diseases are associated with specific genotypes. However, little is known about the molecular basis of phenotypic variation among individuals carrying the same mutation or polymorphism. Here, a highly quantitative approach was taken to examine a relative amount of mRNA from two polymorphic alleles with a coefficient of variation of less than 10% using an RNA difference plot (RDP). RDP analysis revealed that most genes examined were expressed in equal amount from the two alleles in normal lymphocytes. In contrast, the relative amounts of hMSH2 or RB1 mRNAs carrying premature termination codons were significantly reduced compared with those of wild-type mRNAs in lymphocytes from carriers of hereditary, nonpolyposis, colorectal cancer and hereditary retinoblastoma. The balance of allelic expression of the RB1 was also significantly impaired in a pedigree of retinoblastoma carrying a missense mutation in codon 661. The relative expression of the mutant to the wild-type RB1 alleles among the carriers varied from 0.40 to 2.39. The analysis of the expression diversity of a disease-associated allele by RDP could provide a novel approach to elucidating the mechanisms underlying phenotypic variation among individuals carrying an identical mutation or polymorphism at a single locus.     

Bone mass and biochemical parameters in metabolic bone diseases

We studied the relationship between the bone mass and biochemical parameters in 175 normal premenopausal, 72 normal postmenopausal and osteoporotic postmenopausal women, between 20 and 88 years old, and in 40 patients with hyperthyroidism, and 23 patients with primary hyperparathyroidism, between 13 and 64 years old. The bone mineral density (BMD) of the spine (L2-L4) and proximal femur (femoral neck) was measured by dual-energy X-ray absorptiometry using a QDR-1000, Hologic. The bone mineral content (BMC) of the radius was measured by single photon absorptiometry (SPA) using a model 2780, Norland. Serum PTH, BGP and calcitonin (CT) were determined by radioimmunoassay. The BMD of the spine (L2-L4), and the proximal femur in postmenopausal women were negatively correlated with age. The mean BMD in patients with postmenopausal osteoporosis was significantly lower than that in normal postmenopausal women. In postmenopausal women, age was positively correlated with BGP, PTH, CT and negatively correlated with P. In patients with osteoporosis, the BMD of the spine was negatively correlated with serum BGP. The BMC of radius in patients with hyperthyroidism decreased significantly compared with that in the controls, and was negatively correlated with F-T3. The BMC of the radius in patients with primary hyperparathyroidism was significantly lower than that in the controls, and was negatively correlated with serum BGP and serum calcium. The measurements of biochemical parameters such as serum BGP, ALP and PTH may be useful in the assessment of metabolic bone diseases.     

Endometrial adenosquamous carcinoma with osteoclast-like giant cells: immunohistochemistry and histogenesis

Primary extraskeletal epithelial neoplasms containing osteoclast-like giant cells (OGCs) are rare. We herein describe a case of adenosquamous carcinoma that developed in the endometrium together with non-neoplastic OGCs. The patient was a 72-year-old woman who underwent radical hysterectomy with salpingo-oophorectomy and lymph node dissection after being diagnosed with uterine cancer. Histologically, the tumor was found to be an adenosquamous carcinoma containing a large number of OGCs and mononuclear cells (MNCs) that had infiltrated into the stroma. Immunohistochemically, the OGCs and MNCs stained strongly positive for KP-1 and alpha-1-antichymotrypsin, and negative for the epithelial markers epithelial membrane antigen (EMA) and cytokeratins. These findings suggest that the OGCs and MNCs in this patient's tumor originated from monocytes/histiocytes, and most likely developed as part of the stromal reaction to the neoplasm.     

Temporospatial study of the migration and distribution of cardiac neural crest in quail-chick chimeras

It has been demonstrated that the septation of the outflow tract of the heart is formed by the cardiac neural crest. Ablation of this region of the neural crest prior to its migration from the neural fold results in anomalies of the outflow and inflow tracts of the heart and the aortic arch arteries. The objective of this study was to examine the migration and distribution of these neural crest cells from the pharyngeal arches into the outflow region of the heart during avian embryonic development. Chimeras were constructed in which each region of the premigratory cardiac neural crest from quail embryos was implanted into the corresponding area in chick embryos. The transplantations were done unilaterally on each side and bilaterally. The quail-chick chimeras were sacrificed between Hamburger-Hamilton stages 18 and 25, and the pharyngeal region and outflow tract were examined in serial paraffin sections to determine the distribution pattern of quail cells at each stage. The neural crest cells derived from the presumptive arch 3 and 4 regions of the neuraxis occupied mainly pharyngeal arches 3 and 4 respectively, although minor populations could be seen in pharyngeal arches 2 and 6. The neural crest cells migrating from the presumptive arch 6 region were seen mainly in pharyngeal arch 6, but they also populated pharyngeal arches 3 and 4. Clusters of quail neural crest cells were found in the distal outflow tract at stage 23.     

Nuclear expression of phosphorylated EGFR is associated with poor prognosis of patients with esophageal squamous cell carcinoma.

OBJECTIVES: Although it has been reported that epidermal growth factor receptor (EGFR) is able to translocate from the plasma membrane to the nucleus, the pathophysiological role of this translocation in tumorigenicity is still unclear. In the present study, to elucidate the pathophysiological significance of EGFR translocation, we investigated the expression not only of conventional EGFR but also its phosphorylated form (pEGFR), focusing on its cellular localization in esophageal cancer tissues. METHODS: Fifty-two specimens of esophageal squamous cell carcinoma (SCC) obtained by surgery were examined immunohistochemically for their EGFR and pEGFR immunostaining patterns. The relationships between clinicopathological parameters and EGFR or pEGFR immunostaining patterns were then analyzed. RESULTS: In 37 (71.2%) of the 52 esophageal SCCs, EGFR immunoreactivity was clearly localized at the plasma membrane of the cancer cells, whereas pEGFR immunoreactivity was clearly localized in the nucleus in 19 (36.5%) cases. Nuclear expression of pEGFR significantly correlated with TNM stage and lymph node metastasis, and moreover was associated with a poor outcome of esophageal SCC. CONCLUSIONS: Nuclear translocalization of pEGFR is associated with an increase in the malignant potential of esophageal SCC and may affect prognosis in patients with esophageal SCC.     

Incidence of P53 and K-ras alterations in ovarian mucinous and serous tumors

Clarification of the pathogenic relationships existing among ovarian cystadenomas, tumors of low malignant potential (LMP) and various adenocarcinoma types, a series of 29 mucinous and 19 serous ovarian tumors including adenomas, LMP tumors and adenocarcinomas were examined. P53 protein was detected by the streptavidin-biotin method and point mutation of K-ras codon 12 was detected by polymerase chain reaction-restriction fragment length polymorphism analysis. P53 overexpression was observed more frequently in serous adenocarcinomas (5/8, 63%) than in mucinous adenocarcinomas (2/9, 22%) and was correlated with the malignant potential of serous tumors. Furthermore, the proportion of P53-positive cells was significantly higher in serous adenocarcinomas than in mucinous adenocarcinomas. P53 overexpression may therefore be closely related to the early events of carcinogenesis in serous tumors. Although mutation of the K-ras oncogene appears to be an important event in the early tumorigenesis of mucinous tumors, mutation of the K-ras oncogene in serous tumors may be dependent on morphology. Different complex pathways of oncogene and/or tumor suppressor gene abnormalities may be involved in the development of mucinous and serous adenocarcinomas.     

PATHOLOGY OF ULCEROGENIC AND DIARRHEOGENIC TUMORS OF THE PANCREAS

Ulcerogenic and diarrheogenic tumors of the pancreas were studied both light and electron microscopically in the documented cases of two different kinds of tumors to elucidate the histogenesis of non-beta islet cell tumors in reference to islet cells of the normal pancreas.
Argyrophil stain for delta (D) islet cells revealed a few limited number of argyrophil tumor cells, suggesting some relationship to D islet cell as being origin of the ulcerogenic tumor. Alpha (A) cells were not detected in either of ulcerogenic or diarrheogenic tumors. Electron microscopic finding is more confusing. Z-E tumor granules are heterogenous and variable in relatively smaller sizes of 100–130 mμd 170–200 mμ Diarrheogenic tumors have more homogenously smaller granules (100–130 mμ) with minor components of intermediate sizes (150–200 mμ).
Thus, both ulcerogenic and diarrheogenic tumors are quite different from D islet cells (average granule-350 mμ) or antral G cells (average granule-250 mμ), both of which are two different gastrin-producing cells.
A tentative conclusion will be that ulcerogenic tumors originate from gastrin cell similar to antral G cell and diarrheogenic tumors stem from gastrin-antagonist producing cell, presumably similar to the gastric inhibitory peptide (G.I.P.) cell of the small intestine.     

Targeting antigen-specific receptors on B lymphocytes to generate high yields of specific monoclonal antibodies directed against biologically active lower antigenic peptides within presenilin 1

We describe a targeting technique that selects antigen-specific receptors on B lymphocytes using antigen driven selective production of monoclonal antibodies which are directed against functional peptide sequences within the presenilin 1 molecule that is believed to be related to the early-onset of familial Alzheimer's disease. Three different peptide sequences of presenilin 1 were constructed, one including the region around the amino acid position 300, where the putative cleavage site exists and the other two present in the N- and C-terminal regions of that site. The efficiency in production of the desired monoclonal antibodies was at least 5-40-fold that obtained with the poly(ethylene glycol) (PEG)-mediated method. In addition, monoclonal antibodies directed against each of the peptide sequence displayed a high specificity for the corresponding peptide, in contrast to the lack of success using the PEG method. Also, the selection of surface immunoglobulin receptors on B lymphocytes by the peptides of interest was confirmed by immunofluorescent analysis. Here we demonstrate that targeting B lymphocytes results in the successful and efficient production of highly specific monoclonal antibodies against the lower antigenic peptide sequences.     

Possible role of preproghrelin gene polymorphisms in susceptibility to bulimia nervosa.

Previous investigations have suggested that ghrelin, an endogenous orexigenic peptide, is involved in the pathology of eating disorders. We conducted a study to determine whether any preproghrelin gene polymorphisms are associated with eating disorders. Three hundred thirty-six eating disorder patients, including 131 anorexia nervosa (AN)-restricting types (AN-R), 97 AN-binge eating/purging types (AN-BP) and 108 bulimia nervosa (BN)-purging types (BN-P), and 300 healthy control subjects participated in the study. Genotyping was performed to determine the polymorphisms present, and with this information, linkage disequilibrium (LD) between the markers was analyzed and the distributions of the genotypes, the allele frequencies, and the haplotype frequencies were compared between the groups. The Leu72Met (408 C > A) (rs696217) polymorphism in exon 2 and the 3056 T > C (rs2075356) polymorphism in intron 2 were in LD (D' = 0.902, r2 = 0.454). Both polymorphisms were significantly associated with BN-P (allele-wise: P = 0.0410, odds ratio (OR) = 1.48; P = 0.0035, OR = 1.63, for Leu72Met and 3056 T > C, respectively). In addition, we observed a significant increase in the frequency of the haplotype Met72-3056C in BN-P patients (P = 0.0059, OR = 1.71). Our findings suggest that the Leu72Met (408 C > A) and the 3056 T > C polymorphisms of the preproghrelin gene are associated with susceptibility to BN-P.