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At least 91 records · Page 5Linked to original sources
PubMed1995

Cerebrospinal fluid 'neuronal thread protein' comes from serum by passage over the blood-brain barrier.

Cerebrospinal fluid (CSF) biochemical markers for Alzheimer's disease (AD) would be of great value, both to improve clinical diagnostic accuracy and to increase our knowledge of the pathogenesis of the disorder. An increase in the CSF-level of 'neuronal thread protein' (pancreatic thread protein (PTP) immunoreactive material in the brain) has been suggested to be just such a biochemical marker. We have studied CSF 'neuronal thread protein'-like immunoreactivity (NTPLI) using a microparticle enzyme immunoassay. CSF-NTPLI did not differ significantly between AD type I (pure AD) and controls, but was significantly higher in AD type II (senile dementia) and vascular dementia (VAD) as compared with controls. Signs of blood-brain barrier (BBB) damage (elevated CSF/S albumin ratio) were found in both AD type II and in VAD, but not in AD type I. In a multiple ANOVA, with age and CSF/S albumin ratio as covariates, no significant difference in CSF-NTPLI between diagnostic groups was noted though both CSF/S albumin ratio and age (P < 0.0001 and P < 0.001 respectively) were found to influence the CSF-NTPLI level. Since BBB function was found to influence the CSF-NTPLI level, we examined whether NTPLI was present in serum. Indeed, serum NTPLI was about 40 times higher than CSF-NTPLI in neurological patients. Moreover, there was a statistically significant correlation between S-NTPLI and CSF-NTPLI. Taken together, present findings suggest that most of NTPLI in CSF comes from the serum, by passage over the BBB.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Expression of growth factors in a pancreatic islet regeneration model.

In this model of pancreatic regeneration, the initial trophic effect of cellophane wrapping is upon the ductular-epithelium, as shown by autoradiographic analysis following a single pulse of 3H-TdR. The uptake of 3H-TdR by ductular cells is maximal approximately 4 weeks before the peak uptake of the label by islet cells. Six weeks after the pulse, most of the label is contained in differentiating islet cells, not ductular cells. This phenomenon suggests that wrapping of the pancreas induces "progenitor" cells to differentiate along the line of endocrine cells. The essentially negative observations on REG gene expression in the regenerating hamster pancreas indicate that the message for this gene is either not involved in the regeneration process or that it is sufficiently different from the rat gene (a rat control probe was used) that it precludes detection by our methodology. It might be necessary therefore, to generate a hamster REG specific probe in order to further study this issue. In conclusion, the established model of cellophane wrapping of the pancreas provides a useful tool whereby the induced growth of beta-cells can be observed. The sequence appears to be initial stimulation of ductal cells followed by islet differentiation. Of the candidate genes, it appears that reg does not participate in the process. We will however, examine other candidate genes to elucidate the mechanism whereby celophane wrapping induces growth of beta-cells.

Animals↗
PubMed1992

Islet beta-cell regeneration and reg genes.

In this paper, we show that the reg gene is expressed in experimentally induced regenerating or hyperplastic islets. We have previously reported that ectopic expression of the reg gene occurs in some human colonic and rectal tumors, suggesting that enhanced reg expression may be related to the proliferative state of tumor cells. Reg protein has also been shown to have significant sequence homology with plant and animal lectins, a class of compounds that has been shown to be a growth promoter. At present, any direct relationship between reg protein and beta-cell replication remains to be established. However, since the reg protein is a secretory protein and reg can be expressed at an early stage of pancreatic cell differentiation, the reg protein may act on the stem cells of beta-cells in an autocrine or paracrine manner. In normal mature exocrine cells, the reg gene is expressed and the gene product may be necessary to maintain adequate exocrine pancreatic function. The physiological reasons for the maintenance of two functional reg genes encoding proteins of slightly different sequence in mice are still unclear. The cloning of additional rat and human non-allelic reg genes could provide additional clues.

Alloxan↗
PubMed1994

Pancreatic Reg/pancreatic stone protein (PSP) gene expression does not correlate with beta-cell growth and regeneration in rats.

The Reg/pancreatic stone protein (PSP) gene is postulated to be an important regulator of pancreatic beta-cell growth. To investigate this hypothesis, we analysed the expression of the Reg/PSP gene following a 90% pancreatectomy and after chronic glucose infusion, two well-defined models of pancreatic beta-cell growth. There was a rapid induction of the Reg/PSP gene in the remnant pancreas after a 90% pancreatectomy in rats during the period of marked growth of the exocrine and islet tissue. However, a similar rapid, but smaller, induction of the Reg/PSP gene was observed in sham-operated rats and in non-surgical control rats in which there was no enhanced pancreatic growth. Furthermore, there was no pancreatic Reg/PSP gene induction in a model of selective beta-cell growth, the chronic glucose-infused rat. Thus, it is unlikely that Reg/PSP is a beta-cell specific growth factor, even though the function of this important pancreatic gene is still unknown.

Animals↗
PubMed1995

Expression of Reg gene in the Syrian golden hamster pancreatic islet regeneration model.

We have reported previously that cellophane wrapping of the hamster pancreas is a stimulus that leads to the induction of duct epithelial cell proliferation, followed by endocrine cell differentiation and new islet formation. Reg is a candidate gene that has been reported to be expressed in regenerating pancreatic islets, suggesting a role in islet growth. We examined Reg gene expression in the cellophane-wrap model by isolating total RNA from hamster pancreata at various times after wrapping. Northern blot analysis using a rat cDNA Reg probe showed no expression of Reg in control non-wrapped hamster pancreas, whereas a strong signal was detected in control wrapped rat pancreas. Using reverse transcription of RNA followed by polymerase chain reaction (PCR) we amplified, isolated and sequenced a 194 base pair product which showed homology to rat Reg in both control and wrapped hamster pancreas. When the PCR product was used as a probe for Northern blot analysis, no signal was detected in control non-wrapped pancreata. In contrast, a strong signal was detected 1 and 2 days after wrapping, which then returned to basal between 4 and 6 days after wrapping. A similar temporal pattern was observed using in situ hybridization to localize the Reg gene. One- and 2-day wrapped but not control pancreas expressed Reg in acinar cells, but not in islets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Structural analysis of bovine pancreatic thread protein.

Pancreatic thread protein (PTP) forms double helical threads in the neutral pH range after purification, undergoing freely reversible, pH-dependent globule-fibril transformation. The purified bovine PTP consists on SDS gels of two carbohydrate-free polypeptide chains (Gross et al., 1985). Plasma desorption mass spectrometry and amino acid sequence analysis now confirm that bovine PTP contains two disulfide-bonded polypeptides, an A chain of 101 amino acid residues with a molecular weight of 11,073 and a B chain of 35 residues with a molecular weight of 3970. The intact protein exhibits a molecular weight of 15,036, agreeing greater than 99.9% with the molecular weight calculated from the sequence. The B chain sequence was determined by gas-phase Edman degradation of the intact polypeptide. The A chain sequence was determined from overlapping peptides generated by cleavage at lysyl, tryptophanyl, and aspartyl-prolyl residues. Based upon the bovine PTP cDNA structure, the two chains of the protein result from cleavage of a single polypeptide with removal of a dipeptide between the NH2-terminal A chain and COOH-terminal B chain. Comparison of bovine PTP with other proteins reveals significant structural relatedness with the single-chain homologues from human and rat pancreas and with the motif associated with Ca2(+)-dependent carbohydrate recognition domains. The physiological role of PTP has not yet been resolved. The protein is present in very high concentration in pancreatic secretion and it has been detected in brain lesions in Alzheimer's disease and Down syndrome and in regenerating rat pancreatic islets. The present results provide a firm protein base for ongoing molecular, physical-chemical, and structure-function studies of this unusual protein.

Amino Acid Sequence↗
PubMed1993

Idiopathic chronic calcifying pancreatitis with diabetes mellitus. Analysis of pancreatic stone protein gene.

We present a case of a 27-year-old female suffering from chronic calcifying pancreatitis with diabetes mellitus. Radiographic examinations and exocrine pancreatic function tests revealed considerable dilatation of pancreatic ducts with large intraductal calculi and exocrine pancreatic insufficiency, respectively. Recent literature indicates that a decrease in the activity of pancreatic stone protein (PSP), which inhibits CaCO3 crystal formation in pancreatic juice, is closely related to the development of chronic calcifying pancreatitis. The patient had no apparent cause or family history of pancreatitis. We therefore investigated the possibility that alterations in the PSP gene might explain the chronic pancreatitis seen in this patient. Six exons of the PSP gene amplified by polymerase chain reaction were directly sequenced, but there was no apparent base mutation observed. Furthermore, Southern blot analysis revealed neither rearrangement nor deletion of the PSP gene in the genomic DNA of this case. However, this genetic approach will be useful for future study of the etiology of hereditary pancreatitis.

Adult↗
PubMed1986

Etiopathogenesis and definition of chronic pancreatitis.

This is a critical review of papers published on definition, classification, etiology, and pathogenesis of chronic pancreatitis from 1981 to 1985. Articles published earlier will only be mentioned when they are necessary to the understanding of the present knowledge or when they are insufficiently known. The more ancient literature has been reviewed elsewhere. The etiology and pathogenesis section will be limited to calcifying pancreatitis which is the most frequent form of chronic pancreatitis. The etiology of chronic obstructive pancreatitis has been studied in another review. The simple fibrosis of the pancreas is excluded from this chapter.

Alcoholism↗
PubMed1995

Measurement of serum PSP/reg-protein concentration in various diseases with a newly developed enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay, based on two monoclonal antibodies (Hreg1-1 and Hreg101-1) specific for pancreatic stone protein (PSP)/reg-protein, was developed to determine the concentration of this protein in serum from individuals with various diseases. The serum concentration of PSP/reg-protein was significantly higher in patients with various pancreatic diseases than in normal controls, and was also significantly higher in patients with acute pancreatitis or chronic relapsing pancreatitis than in patients with chronic pancreatitis. Furthermore, the serum PSP/reg-protein concentration was also significantly increased in liver cirrhosis, choledocholithiasis, and various cancers of the digestive system, and was extremely high in all patients tested with chronic renal failure. A significant correlation was apparent between the serum concentration of PSP/reg-protein and elastase-I in 68 patients with chronic pancreatitis or pancreatic cancer. Whereas only 7 of these patients showed a normal serum PSP/reg-protein concentration and a significantly increased elastase-I concentration, 15 of these patients showed a significantly increased serum PSP/reg-protein concentration and a normal serum elastase-I concentration. These results indicate that the serum PSP/reg-protein concentration may reflect pancreatic damage, especially in acute pancreatitis, and may be a sensitive a marker for such damage as elastase-1, although false positivity was apparent in renal failure and in some patients with hepatic dysfunction or digestive system malignancies.

Antibodies, Monoclonal↗
PubMed1995

Insulin-induced differentiation and modulation of neuronal thread protein expression in primitive neuroectodermal tumor cells is linked to phosphorylation of insulin receptor substrate-1.

Neuronal thread proteins (NTPs) are a family of developmentally regulated molecules expressed in central nervous system (CNS) neurons and primitive neuroectodermal tumor (PNET) cell lines. NTP gene expression is modulated with DNA synthesis, neuritic sprouting, and neuronal differentiation. The present study explores the mechanism of insulin modulation of NTP gene expression during neuronal differentiation using PNET cell lines of CNS origin. PNET2 cells underwent neuronal differentiation with neurite outgrowth coupled with transient up-regulation of several species of NTP. In contrast, PNET1 cells failed to differentiate in response to insulin stimulation, although insulin receptors were more abundant than in PNET2 cells. Analysis of the insulin-mediated signal transduction pathway demonstrated that the lack of insulin responsiveness in PNET1 cells was primarily caused by impaired insulin-mediated tyrosyl phosphorylation of the insulin receptor substrate-1 (IRS-1). Correspondingly, the association between phosphatidyl-inositol 3 (PI3) kinase and phosphorylated IRS-1 was reduced in PNET1 compared with PNET2 cells. In contrast, the levels of IRS-1 protein were similar in PNET1 and PNET2 cells, and expression of the insulin receptor beta subunit (Ir beta) and insulin-mediated tyrosyl phosphorylation of the Ir beta were greater in PNET1 than PNET2 cells. The findings suggest that insulin effected neuronal differentiation and modulation of NTP gene expression in PNET cells utilizes a signal transduction cascade that requires tyrosyl phosphorylation of IRS-1.

Blotting, Western↗
PubMed1986

Chemical studies of pancreatic nonopaque concretions and protein plug.

Chemical studies were performed on all or part of four X-ray translucent (nonopaque) concretions and one protein plug to investigate a possible relationship between these substances, and to find the similarities and differences between these materials and pancreatic stone protein. Through elemental analysis, infrared absorption spectrometry, quantitative analysis of protein, and amino acid analysis, nonopaque concretions and protein plug were found to consist mainly of protein. One nonopaque concretion contained a very small amount of crystalline which differed greatly from calcite type calcium carbonate as observed in pancreatic calcified stones. The pattern of amino acid composition was very similar between the concentrations and the protein plug: rich in acidic amino acids, but poor in basic and aromatic residues. The aspartic acid content was the highest among detected amino acids. Comparison of amino acid composition between the nonopaque concretions which we analyzed and the pancreatic stone protein reported from Sarles' laboratory suggested that the concretions seem to contain some stone protein.

Adult↗
PubMed1993

Serum pancreatic stone protein in pancreatic diseases.

Serum pancreatic stone protein (PSP) was determined in sera of pancreatic and nonpancreatic diseases using enzyme immunoassay specific to human PSP to study the diagnostic and pathophysiological significance of PSP. Serum PSP in acute pancreatitis (mean +/- SD = 1075.4 +/- 2849.1 ng/mL, n = 33) was significantly higher than that in controls (78.6 +/- 31.8 ng/mL, n = 37, p < 0.01), chronic pancreatitis (156.8 +/- 82.8 ng/mL, n = 32, p < 0.05), and pancreatic cancer (148.468.8 ng/mL, n = 26, p < 0.05). No significant difference was found between noncalcified and calcified chronic pancreatitis. Serum PSP levels were significantly higher in chronic renal failure under hemodialysis (1796.0 +/- 1492.9 ng/mL) than in other diseases such as peptic ulcer, liver cirrhosis, gallstone, and diabetes mellitus. Low but significant correlation was obtained between serum PSP and serum immunoreactive trypsin (r = 0.22, p < 0.05). Increased serum PSP levels in acute pancreatitis and chronic renal failure suggest that serum PSP levels reflect reflex from pancreatic secretion, release from damaged pancreatic acinar cells, or retention in circulation, and can be useful for diagnosis of acute pancreatitis, but not chronic calcified pancreatitis.

Acute Disease↗
PubMed1993

The immunohistochemical evaluation of PSP/reg-protein in normal and diseased human pancreatic tissues.

In order to elucidate the characteristics of reg-protein, which is identical to pancreatic stone protein (PSP/reg-protein), and the relationship between the generation and evolution of chronic pancreatitis and the expression of PSP/reg-protein in the pancreas, we investigated the expression of PSP/reg-protein in normal and diseased human pancreatic tissues by immunohistochemistry. The PSP/reg-protein was expressed in all cases with normal pancreas or chronic pancreatitis, and in 70.6% of cases with pancreatic cancer. This protein was present in the cytoplasm of acinar cells and, in some cases, in the intraluminal contents of ductules in nonmalignant tissues. From the view of distribution and cellular localization, PSP/reg-protein was expressed more broadly and densely in chronic pancreatitis with mild to moderate injury than in the normal pancreas. However, the protein was less expressed in severely damaged chronic pancreatitis tissue, such as calcifying pancreatitis, than in the normal pancreas. These findings suggest that mild to moderate injury to pancreatic tissue may stimulate the synthesis of PSP/reg-protein, whereas more severe injury tends to depress it.

Calcium-Binding Proteins↗