Inhibitory effect of 2,4-dihydroxyphenylacetylasparagine, a common moiety of spider toxin, on glutamate binding to rat brain synaptic membranes

2,4-Dihydroxyphenylacetylasparagine (2,4-DHPA-ASN), a common moiety of molecules of spider toxins, was shown to inhibit L-[3H]glutamic acid binding to rat brain synaptic membranes in a dose-dependent manner. The inhibitory effect of 2,4-DHPA-ASN was almost the same as that of intact spider toxin isolated from Nephila clavata, but significantly higher than that of 2,4-dihydroxyphenylacetic acid (2,4-DHPA). In addition, neither 2,4-dihydroxybenzoic acid nor the isomers of 2,4-DHPA suppressed the glutamate binding. These results suggested that 2,4-DHPA might be the functional part and asparagine in the molecules of spider toxins seemed to cause increasing affinity toward the recognition site of glutamate binding.     

ISOLATED ADRENOCORTICOTROPIC HORMONE (ACTH) DEFICIENCY

The case to be reported is that of a 72-year-old woman with isolated adrenocorticotropic hormone (ACTH) deficiency, who complained of anorexia and generalized malaise. The secretions of human growth hormone(HGH), prolactin (PRL), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH) were all within normal limit. In spite of the extremely low level of Cortisol, the plasma level of AGTH would not rise sufficiently, but a marked response of Cortisol to AGTH stimulation was recognizaed. The postmortem examination revealed a decrease In basophilic or PAS-positive cells of the anterior pituitary gland which also showed a selective loss of AGTH-secreting cells over immunohistochemical study. Electron microscope could easily visualize somatotroph, mammotroph, thyrotroph, FSH- and LH-gonadtroph, but corticotroph was difficult to be discerned. Adrenocortical cells demonstrated atrophy and degeneration, for which the zona fasciculata and zona reticularis were narrowed. The zona glomerulosa was slightly enlarged In width.     

IMMUNOHISTOCHEMICAL DEMONSTRATION OF PEPTIDE YY IN GASTROINTESTINAL ENDOCRINE TUMORS

Fourteen cases of gastrointestinal endocrine tumors were examined im-munohistochemically for peptide YY, pancreatic polypeptide, glucagon, and somatostatin. Peptide YY cells were present in seven tumors, pancreatic polypeptide cells in eight tumors, glucagon cells in six tumors, and somatostatin cells in nine tumors. All 7 rectal endocrine tumors examined were found to contain peptide YY, while in the tumors of the other sites peptide YY cells were not detected. Peptide YY cell population in the rectal tumors was small to moderate in comparison with pancreatic polypeptide and glucagon cell population. This study suggests that peptide YY cells may be a common constituent of rectal endocrine tumors together with pancreatic polypeptide and glucagon cells, and that the peptide YY spectrum of gastrointestinal endocrine tumors may be closely related to the location of the tumors. Moreover, it can also be said that peptide YY may be used as one of the markers of rectal endocrine tumors.     

Expression of matrix metalloproteinase-2 (MMP-2) and of membrane-type-1-matrix metalloproteinase (MT1-MMP) in transitional cell carcinoma of the upper urinary tract

Tumor cell invasion and metastasis are biologically dependent on the proteolytic destruction of surrounding matrix components. Matrix metalloproteinase-2 (MMP-2) is able to cleave type IV collagen, and membrane-type-1-matrix metalloproteinase (MT1-MMP) induces activation of proMMP-2. We investigated the expression of MMP-2 and MT1-MMP using in situ hybridization and immunohistochemistry in 102 cases of transitional cell carcinoma of the upper urinary tract (TCC-UUT). A positive expression of each metalloproteinase was recognized in all samples and was apparent within the cytoplasm of tumor epithelial cells and/or stromal cells situated at the interface between tumor and stroma. Our analysis of clinicopathologic findings showed a relationship between MMP-2 and MT1-MMP expression and stage. The correlation between the MMP-2 protein staining score for tumor epithelial cells and overall survival rate reached significance in the univariate analysis. However, only stage was associated with disease-free and overall survivals in the multivariate analysis. In conclusion, the detection of MMP-2 and MT1-MMP would appear to be of limited value in informing the prognosis of TCC-UUT.     

Effects of long-term acidification of extracellular pH on ATP-induced calcium mobilization in rabbit lens epithelial cells

ATP-induced calcium (Ca2+) mobilization was investigated in rabbit lens epithelial cells that had been cultured in a medium with pH of 7.4 (group 1), 7.2 (group 2), or 7.0 (group 3) for 10 to 21 d. Intracellular free Ca2+ ([Ca2+]i and pH (pHi) were measured by using fluorescent dyes, fura-2 and BCECF, respectively. The long-term acidification decreased the pHi to 7.15 +/- 0.01, from 7.22 +/- 0.01, in group 2 and to 7.09 +/- 0.01 in group 3. The administration of 10 micromol/l ATP produced an initial peak followed by a sustained increase in [Ca2+]i in the lens cells of group 1. Both the initial peak and the sustained increase in [Ca2+]i were enhanced in groups 2 and 3. The initial peak was abolished by pretreatment with 1 micromol/l thapsigargin, an ER Ca2+ pump inhibitor, but was not affected by the removal of extracellular Ca2+. On the other hand, the sustained increase was suppressed either by the thapsigargin treatment or by the Ca2+ removal. Treatment with only thapsigargin caused a sustained increase in [Ca2+]i that was greater in group 3 than in group 1. These results suggest that (1) the ATP-induced initial peak in [Ca2+]i is due to Ca2+ release from the intracellular stores, (2) the sustained increase in [Ca2+]i is mediated through either Ca2+ influx from the extracellular space or Ca2+ release from the store triggered by the Ca2+ influx, and (3) long-term, moderate acidification enhances both the initial peak and the sustained increase in [Ca2+)]i in rabbit lens epithelial cells. One possible mechanism of the ATP-induced Ca2+ influx seems to be a capacitative Ca2+ entry pathway.     

Nuclear accumulation of beta-catenin and transcription of downstream genes are regulated by zygotic Wnt5alpha and maternal Dsh in ascidian embryos.

Nuclear beta-catenin plays crucial roles in the establishment of the embryonic axis and formation of mesendoderm tissues in ascidians and other animals. However, the cue responsible for nuclear accumulation of beta-catenin in the vegetal hemisphere is still unknown in ascidians. Here, we investigated the roles of Wnt5alpha and Dsh in the nuclear accumulation of beta-catenin and activation of its downstream genes in the ascidian Halocynthia roretzi. Wnt5alpha knockdown embryos lost nuclear accumulation of beta-catenin at the 64-cell stage but not at the 32-cell stage, and expression of Hr-lim, one of the targets of beta-catenin, was impaired in the anterior region of the embryo. Zygotic Wnt5alpha expression in the anterior-vegetal blastomeres was primarily responsible for these defects. Dsh knockdown showed no effect on nuclear localization of beta-catenin, but inhibited Hr-lim expression in the posterior region. These results suggest that maintenance of nuclear Hr-beta-catenin after the 64-cell stage is regulated by zygotic Hr-Wnt5alpha, and that expression of its target genes is modulated by both Hr-Wnt5alpha and Hr-Dsh. Our results also highlight the importance of nuclear accumulation of beta-catenin up to the 32-cell stage through a still unclarified mechanism.     

The inferior supernumerary renal arteries: A classification into three types

Among cases that had multiple renal arteries on one side, an inferior supernumerary renal artery was found in 24/270 cases (ca. 9%) on the right and in 19/270 cases (ca. 7%) on the left, together with the usual renal artery. We have noticed that there are correlations between their levels of origin from the aorta and their positional relation to the ureter and the inferior vena cava (IVC). An inferior supernumerary renal artery (InfRA) of lower origin passes in front of the IVC and behind the ureter. An InfRA of middle origin passes in front of both the IVC and the ureter. An InfRA of upper origin passes behind the IVC and in front of the ureter or renal pelvis. In addition there was a tendency for the lower origin type to have an ureteric branch, while the middle and upper origin types had a gonadal branch. These findings suggest that different derivations lead to the inferior supernumerary renal arteries.