Tra2ß protects against the degeneration of chondrocytes by inhibiting chondrocyte apoptosis via activating the PI3K/Akt signaling pathway.

OBJECTIVE: Osteoarthritis (OA) is a common disease in the elderly and seriously affects the quality of life of patients. Tra2ß is a protein that has been found to activate PI3K/Akt in recent years. The purpose of this study was to explore the protective effects of Tra2ß on chondrocytes and its mechanisms. PATIENTS AND METHODS: The expression of Tra2ß in knee cartilage tissue of patients with OA and normal people was compared. In addition, human primary chondrocytes were cultured, the expression of Tra2ß in chondrocytes by cell transfection was changed, and its effects on extracellular matrix, inflammation, and apoptosis in chondrocytes were examined. LY294002 was also used to inhibit the activity of PI3K/Akt signaling pathway to verify the mechanism of Tra2ß to protect chondrocytes. RESULTS: The expression of Tra2ß in the cartilage tissue of the OA group was significantly lower than that of the control group, and the IL-1ß-induced chondrocytes also expressed the lower Tra2ß. The overexpression of Tra2ß increased the expression of extracellular matrix collagen II and decreased the expressions of MMP3/13, inflammatory factors (IL-6, IL-8 and TNF-α), and apoptotic factors (caspase3/9, Bax). In addition, the overexpression of Tra2ß also increased expression and phosphorylation of PI3K and Akt. However, LY294002 attenuated the protective effect of Tra2ß on chondrocytes by inhibiting the PI3K/Akt signaling pathway. CONCLUSIONS: Tra2ß activates the PI3K/Akt signaling pathway, reduces the degradation of extracellular matrix of chondrocytes, reduces the level of inflammation and apoptosis of chondrocytes, and thus, plays a role in the treatment of OA.

Imperatorin ameliorates learning and memory deficits through BDNF/TrkB and ERK/CaMKIIα/CREB signaling in prenatally-stressed female offspring.

Prenatal stress (PS) can lead to impaired spatial learning and memory in offspring. Imperatorin (IMP) is a naturally occurring furanocoumarin with many pharmacological properties. However, the effects of IMP on cognitive impairment induced by PS and the underlying molecular mechanisms remain unclear. We investigated the protective effect of IMP treatment after PS on learning and memory deficits in female offspring at postnatal 60 days. After treating prenatally-stressed offspring with IMP (15 and 30 mg/kg) for 28 days, we found that IMP increased body weight and ameliorated spatial learning and memory and working memory deficits in female offspring rats. Meanwhile, hippocampal Glu and serum corticosterone levels in prenatally-stressed offspring were significantly decreased after IMP administration. Additionally, IMP treatment significantly increased BDNF, TrkB, CaMKII, and CREB mRNA expression in the hippocampus of offspring rats. Furthermore, PS-mediated induction of RKIP protein and mRNA expression and glucocorticoid receptor protein expression in the hippocampus of offspring rats were significantly decreased by IMP treatment, and the protein expression of BDNF and TrkB and relative levels of p-EKR/ERK, p-CaMKIIα/CaMKIIα, and p-CREB/CREB were remarkably increased after IMP treatment. Taken together, IMP can ameliorate PS-induced learning and memory deficits through BDNF/TrkB and ERK/CaMKIIα/CREB signaling pathway and hypothalamic-pituitary-adrenal axis.

Pretreatment With Erythropoietin Attenuates Intestinal Ischemia Reperfusion Injury by Further Promoting PI3K/Akt Signaling Activation.

BACKGROUND: Erythropoietin (EPO) has been shown to be beneficial in resolution of acute inflammation and intestinal ischemia/reperfusion (IR) injury is featured by the excessive immune response. The current research is designed to evaluate the effect and potential mechanisms of EPO on the intestinal IR injury. Therefore, the effect of EPO on intestinal IR injury was examined by the change of intestinal histology; the expression of pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and interferon γ (IFN-γ); and the protein levels of EPOR, p-EPOR, p85, p-p85, Akt, p-Akt, IκΒ-α, p-p65, and p65. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were randomly divided into three groups: sham group (sham), IR-saline group (IRI), and the IR-EPO group (EPO). Rats were treated with EPO (5000 U/kg) 1 hour before IR induction. A rat model of IR injury was established by ligating the superior mesenteric artery for 30 minutes, followed by reperfusion for 1 hour. Intestinal histology, pro-inflammatory cytokines, and mediators were assessed. The effect of EPO on PI3K/Akt/NF-κB signaling and EPOR were also measured. RESULTS: EPO significantly decreased the pathologic changes of intestinal and reduced the elevation of pro-inflammatory cytokines TNF-α, IL-1ß, and IFN-γ in intestinal and serum caused by IR which was associated with suppressing NF-κB activation by further promoting activation of PI3K/Akt signaling. CONCLUSIONS: EPO ameliorated the acute intestinal injury caused by IR, which was associated with further activating PI3K/Akt signaling to suppress NF-κΒ-mediating inflammation. Our findings suggest that EPO could be useful for preventing IR-induced intestinal injury.

Reproducibility of anterior chamber angle measurement using the Tongren ultrasound biomicroscopy analysis system.

PURPOSE: To assess the intraobserver and interobserver variability of new software for the analysis of anterior chamber-angle images obtained using ultrasound biomicroscopy (UBM). PATIENTS AND METHODS: Consecutive UBM images of 4 quadrants (the superior, the nasal, the temporal, and the inferior) of 30 primary angle-closure suspects (PACSs) and 30 normal subjects with open angles were selected. Two observers used the new UBM image analysis software to calculate the following parameters on 2 separate occasions: angle opening distance (AOD), trabecular-iris angle (TIA), angle recess area (ARA), trabecular-ciliary process distance (TCPD), iris-ciliary process distance (ICPD), and iris thickness (IT). Intraobserver and interobserver reproducibility were measured using intraclass correlation coefficient (ICC) and Bland-Altman plots. RESULTS: For intraobserver measurements in PACS, the range of ICC for AODs, TIAs, ARAs, TCPDs, ICPDs, and ITs in the 4 quadrants were 0.77 to 0.94, 0.80 to 0.92, 0.82 to 0.94, 0.51 to 0.73, 0.42 to 0.78, and 0.76 to 0.89; in open angles, these were 0.83 to 0.94, 0.80 to 0.93, 0.84 to 0.93, 0.57 to 0.89, 0.57 to 0.84, and 0.70 to 0.95. For interobserver measurements in PACS, the range of ICC for AODs, TIAs, ARAs, TCPDs, ICPDs, and ITs in the same quadrants as above were 0.52 to 0.89, 0.65 to 0.92, 0.68 to 0.92, 0.22 to 0.80, 0.48 to 0.93, and 0.29 to 0.75; in open angles, these were 0.57 to 0.87, 0.60 to 0.86, 0.64 to 0.90, 0.27 to 0.94, 0.56 to 0.93, and 0.28 to 0.66. CONCLUSIONS: Angle width (AOD, TIA, and ARA) and IT of both PACS and open angles could be reliably measured by the same observer; interobserver measurements and those related to the ciliary process (TCPD and ICPD) were more variable. For the current version of this software, we recommend measurements of anterior chamber parameters by the same observer.

Gastroduodenal arterial reconstruction of the pancreaticoduodenal allograft.

Simultaneous procurement of the pancreas and liver necessitates division of vessels supplying both organs. The integrity of the pancreatic arterial supply appears to be related to surgical complications after pancreas transplantation. We have described herein three cases of gastroduodenal artery (GDA) reconstruction during pancreas transplantation, and reviewed other options for GDA reconstruction. These techniques performed safely during bench reconstruction can be applied to various clinical situations.

MRI-based investigation on outflow segment of cerebral venous system under increased ICP condition.

OBJECTIVE: Increased intracranial pressure (ICP) is responsible for causing most nervous system diseases to progress seriously, till death. Recently, volume-targeted therapeutic strategy against increased ICP, which works by releasing excessive intracranial liquid especially from the venous compartment, attracted a great deal of attention. Previous research by us found a structurally special "outflow segment cuff" that is located at the juncture of superior sagittal sinus (SSS) and the brain-bridging veins in porcine model. Sequential observation demonstrated that this special structure appeared to have functional abnormalities. Based on these findings, it was proposed to try and prove a further hypothesis that there exists a similar structure in human beings that might be of importance for cerebral venous system to intervene in volume-initiated ICP regulation. Meanwhile, the diameters of bridging veins under either increased or normal ICP are compared by means of magnetic resonance imaging (MRI). METHOD: Forty patients who presented with increased ICP were selected to undergo 2D time of flight (TOF) venography and ten normal volunteers were taken as the control group. Increased intracranial pressure status was evaluated by using flash visual evoked potential (fVEP) technique. All the patients and volunteers underwent 2D-TOF MRI imaging for the following parameters: repetition time/echo time, 50/4.9 milliseconds; flip angle, 45 degrees ; field of view, 250x250 mm; matrix, 256x256 pixels; section thickness, 1.5 mm. Syngo fastview imaging system was used to process and analyze the targeted brain-bridging venous section. RESULTS: By using 2D-TOF method in vivo, most bridging venous profiles as well as SSS and vicinal cortical veins could be clearly visualized. A short and narrow section, as previously described, obviously emerged because of MRI signal weakness even disappearing at the juncture of SSS and bridging veins in increased ICP patients. In combination with previous animal morphological findings we believe that this section with abnormal MRI signal could stand for the human counterpart of "outflow segment cuff" in porcine. Such a special structure could be observed within a majority of increased ICP patients (32/40 cases), whereas only one case presented the existence of similar imaging signal weakness. Furthermore, the diameters of the bridging veins in increased ICP group are statistically larger than the control group. CONCLUSION: Intracranial venous compartment occupies about 70 to 80% blood volume inside the inflexible cranial cavity. Following volume-targeted rationale, ICP can be regulated effectively by the fluctuation of venous blood volume based on different aspects of morphology, biomechanics, and hemodynamics. In the present study, the coincidence of animal model and human venography in vivo offers strong evidences to support the hypothesis that venous hemodynamics, although passively, influences intracranial pressure environment through a possible key regulator - outflow segment narrow structure. The fact that this narrow formation and proximal vascular dilation appears more in patients under high ICP condition rather than in patients with normal pressure. Both narrow formation and proximal vascular dilation indicate its significant contribution to intracranial venous congestion, resulting from difficult drainage and the close relationship between intracranial venous volume and ICP.

Single-nucleotide polymorphisms in the lipoprotein lipase gene associated with coronary heart disease in Chinese.

Coronary heart disease is a complex disease reflecting the interaction of multiple genes with the environment (e.g. diet, life style). Lipoprotein lipase (LPL) plays an important role in lipid metabolism and the pathogenesis of coronary atherosclerosis. Recent associations between single-nucleotide polymorphisms in the LPL gene and heart disease have been reported, but little is known in Chinese. The LPL gene spans >26 kb, with an mRNA of 3549 bp. In the present study, we screened 5155 bp (565 bp of 5' flanking region, nine exons and donor- and acceptor-splice sites, and some intronic bases) in 160 Chinese patients with confirmed coronary heart disease and 150 age- and gender-matched controls. Thirteen of the sixteen single-nucleotide polymorphisms that we found have not been previously reported. In males, significant (P<0.05) differences between the coronary heart disease patients and controls were found for five single-nucleotide polymorphisms: -421G>A (5' flanking region); +13,577C>A (intron 2); +16,052G>A, R192Q (exon 5); +16,173C>G and +16,177T>C (intron 5). In females, significant differences between the patients with coronary heart disease and controls were found for only the -421G>A and +16,052G>A (R192Q) mutations. Among the coronary heart disease males, significant (P<0.05) associations were found between the low-HDL high-triglyceride (LHDL/HTG) phenotype and the non-LHDL/HTG trait for the 5' flanking-421G, the intron 2+13,577C, and the exon 5+16,052G mutations, with odds-ratios (ORs)[confidence intervals] of 3.90[1.12-13.66], 3.38[1.22-9.40], and 3.22[1.04-10.01], respectively; no corresponding associations were found in females. There were 69, 51, 57 and 41 unphased haplotype patterns in male coronary heart disease, male control, female coronary heart disease and female control groups, respectively; the computer program PM-Plus found the heterogeneity model by far the best fit (P<0.0001 in males, >0.01 in females). These data show that some single-nucleotide polymorphisms in the LPL gene among Chinese are associated with abnormal lipid and lipoprotein profiles and predisposition to coronary heart disease, a genetically heterogeneous complex disease, and that they are gender-specific.

Top-quark spin correlations at hadron colliders: predictions at next-to-leading order QCD.

The collider experiments at the Tevatron and the LHC will allow for detailed investigations of the properties of the top quark. This requires precise predictions of the hadronic production of tt pairs and of their subsequent decays. In this Letter we present for the reactions pp, pp-->tt+X-->l+l'-+X the first calculation of the dilepton angular distribution at next-to-leading order in the QCD coupling, keeping the full dependence on the spins of the intermediate tt state. The angular distribution reflects the degree of correlation of the t and t spins which we determine for different choices of t and t spin bases. In the case of the Tevatron, the QCD corrections are sizable, and the distribution is quite sensitive to the parton content of the proton.

Absorption spectra of the 4f electron transitions of the praseodymium complex with 1-cyclopropyl-6-fluoro-1,4-dihydro-7-(4-ethyl-1-piperazinyl) -4-oxo-3-quinoline carboxylic acid hydrochloride and its analytical application.

The absorption spectra of the praseodymium complex with 1-cyclopropyl-6-fluoro-1,4-dihydro-7-(4-ethyl-1-piperazinyl)-4-oxo-3- quinoline carboxylic acid hydrochloride (NNFX) has been studied by normal and derivative spectrophotometry. The complex showed maximum absorption at 350 nm at pH 6.0. The stoichiometry of the Pr-NNFX complex was calculated by the molar ratio and continuous variation methods. The ratio of Pr to NNFX was 1:3. The absorption bands of the 4f electron transitions of the praseodymium complex with NNFX are enhanced markedly, especially the wavelength at 481 nm. Using the third-derivative spectrum, the calibration graph is linear over the range 2.5 x 10(-5)-3.5 x 10(-4) mol dm-3 for praseodymium. The detection limits (signal-to-noise ratio of 2) is 1.4 x 10(-6) mol dm-3. The relative standard deviation is 1.2% for 7.0 x 10(-5) mol dm-3 of praseodymium. A method for the direct determination of praseodymium in rare earth mixtures with good accuracy and selectivity is described.

Envelope glycoprotein determinants of neutralization resistance in a simian-human immunodeficiency virus (SHIV-HXBc2P 3.2) derived by passage in monkeys.

The simian-human immunodeficiency virus SHIV-HXBc2 contains the envelope glycoproteins of a laboratory-adapted, neutralization-sensitive human immunodeficiency virus type 1 variant, HXBc2. Serial in vivo passage of the nonpathogenic SHIV-HXBc2 generated SHIV KU-1, which causes rapid CD4(+) T-cell depletion and an AIDS-like illness in monkeys. A molecularly cloned pathogenic SHIV, SHIV-HXBc2P 3.2, was derived from the SHIV KU-1 isolate and differs from the parental SHIV-HXBc2 by only 12 envelope glycoprotein amino acid residues. Relative to SHIV-HXBc2, SHIV-HXBc2P 3.2 was resistant to neutralization by all of the antibodies tested with the exception of the 2G12 antibody. The sequence changes responsible for neutralization resistance were located in variable regions of the gp120 exterior envelope glycoprotein and in the gp41 transmembrane envelope glycoprotein. The 2G12 antibody, which neutralized SHIV-HXBc2 and SHIV-HXBc2P 3.2 equally, bound the HXBc2 and HXBc2P 3.2 envelope glycoproteins on the cell surface comparably. The ability of the other tested antibodies to achieve saturation was less for the HXBc2P 3.2 envelope glycoproteins than for the HXBc2 envelope glycoproteins, even though the affinity of the antibodies for the two envelope glycoproteins was similar. Thus, a highly neutralization-sensitive SHIV, by modifying both gp120 and gp41 glycoproteins, apparently achieves a neutralization-resistant state by decreasing the saturability of its envelope glycoproteins by antibodies.

Collagen I/III and matrix metalloproteinases (MMP) 1 and 13 in the fascia of patients with incisional hernias.

The late appearance ofincisional hernias several years after laparotomy and the high recurrence rates after operation strongly imply the presence of a disorder of the connective tissue, although a specific defect in patients with incisional hernias has not yet been identified. In the present study we used both immunohistochemistry and Western blot analysis to evaluate the ratio of collagen I and III and the expression of the metalloproteinases (MMP) 1 and 13 in the fascia of patients with incisional or recurrent incisional hernias. Samples of healthy skin or stable skin scar in patients without hernias served as controls. Altogether, our data indicated a significantly decreased ratio of collagen I/III in the fascia of patients with incisional hernias and recurrent incisional hernias. Furthermore, in these patients the expression of MMP-1 was decreased compared to the controls, whereas MMP-13 could not be detected in any fascia sample, with or without hernias present. For the first time, our results give evidence of the existence of a possible collagen disorder in these patients. The decreased ratio ofcollagen I/III is explainable due to a relative increase of collagen type III, which is known to be characterized by thin fibril diameters and lowered mechanical strength. The altered collagen ratio might be the result of the decreased activity of MMP-1, whereas the absent MMP-13 expression did not seem to modify the scar formation. Thus, our data indicate the presence of collagen metabolic disorders in patients with incisional hernias and recurrent incisional hernias. Furthermore, these results might explain the poor results of a mesh-free hernia repair, which again builds up scar tissue of inadequate collagen composition and strength.

Development of human fetal pancreas after transplantation into SCID mice.

Only a small component of human fetal pancreas consists of beta cells, and yet this tissue is capable of normalizing the blood glucose levels of diabetic recipients when transplanted. The time taken to achieve this goal is several months, during which time the tissue proliferates and eventually differentiates into beta cells. The dynamics of beta cell development have not been described previously. We transplanted human fetal pancreas beneath the renal capsule of immunodeficient mice and analysed the grafts for a period of 12 weeks using antibodies against exocrine cells (lipase), endocrine cells and protodifferentiated duct cells. Exocrine cells constituted 48% of all epithelial cells in the untransplanted pancreas, with duct cells comprising 29% and endocrine cells 16% (beta cells 7%). The percentage of exocrine cells declined with time after transplantation, with only a small number undergoing apoptosis, and the duct cells increased, the values for these two cell types at 12 weeks being 20 and 57%, respectively. Both cell types appeared to proliferate equally for up to 8 weeks after transplantation, but only duct cells thereafter. Endocrine cells began to increase from 8 weeks after transplantation, representing 28% of epithelial cells (beta cells 11%) at this time. Intermediate cells, that is, cells expressing the characteristics of more than one type of mature pancreatic cell, were observed both in the ungrafted pancreas and after transplantation. The commonest intermediate cell type was duct/exocrine, with exocrine/endocrine and duct/endocrine cells also observed, suggesting active transdifferentiation from one cell type to another. We hypothesize that following the transplantation of human fetal pancreatic tissue, exocrine cells mostly transdifferentiate into duct cells and these eventually develop into endocrine cells, in particular beta cells.

In vitro dedifferentiation of fetal porcine pancreatic tissue prior to transplantation as islet-like cell clusters.

The fetal porcine pancreas under experimental conditions can be transplanted in the form of explants or islet-like cell clusters (ICCs) to normalize blood glucose levels in diabetic recipients. ICCs are released from the collagenase-digested pancreas and require a 4- to 5-day culture period for their complete formation. In order to maximize insulin producing beta cell differentiation following transplantation, an understanding of ICC development is essential to utilize this alternative treatment for type 1 diabetes. In this study a role is proposed for exocrine cells in the generation of the multipotent pancreatic precursor cells during the culture period. Acinar cells undergo dedifferentiation during the initial stages of the culture period into multipotent pancreatic precursor cells, previously called protodifferentiated cells. The progressive loss of exocrine differentiation appears to involve rapid degranulation of zymogen granules by exocytosis and loss of the prominent secretory apparatus. These processes occur in parallel with a significant reduction in the expression of lipase in the period from day 0 to day 5 and simultaneously there is an increase in the epithelioid/ductal cell marker, cytokeratin 20. Using proliferating cell nuclear antigen, cell proliferation during the culture period does not appear to account for the increase in epithelioid/ductal cells. Further the rates of apoptosis and necrosis which were identified using the TUNEL technique and propidium iodide, respectively, do not appear to account for the reduction in exocrine cell numbers. Exocrine cell dedifferentiation appears to increase the pool of protodifferentiated cells which have the potential to develop into the insulin-producing beta-cell population following transplantation into the diabetic recipient

[Studies on morphology and histology of medicinal part of Corydalis yanhusuo].

OBJECTIVE: To Study the morphology, microstructure and morphosis of medicinal part of Corydalis yanhusuo, and provide a basis for the knowledge of the type of modified stem of Corydalis yanhusuo and the identification of crude drug. METHOD: Sample collection, culture observation and microsectile observation. RESULT: Morphological and histological characters and morphogenetic and developmental regulation of medicinal part of Corydalis yanhusuo are described with pictures. CONCLUSION: The medicinal part of Corydalis yanhusuo is bulb, and the conception that the medicinal part of Corydalis yanhusuo is tuber is wrong.

Association of structural changes in the V2 and V3 loops of the gp120 envelope glycoprotein with acquisition of neutralization resistance in a simian-human immunodeficiency virus passaged in vivo.

The in vivo passage of a neutralization-sensitive, laboratory-adapted simian-human immunodeficiency virus (SHIV-HXBc2) generated a pathogenic, neutralization-resistant virus, SHIV-HXBc2P 3.2. SHIV-HXBc2P 3.2 differs from SHIV-HXBc2 only in 13 amino acid residues of the viral envelope glycoproteins. Here we used antibody competition analysis to examine the structural changes that occurred in the SHIV-HXBc2P 3.2 gp120 exterior envelope glycoprotein. The relationships among the antibody epitopes on the conserved gp120 core of SHIV-HXBc2 and SHIV-HXBc2P 3.2 were similar. The third variable (V3) loop was more closely associated with the fourth conserved (C4) region and CD4-induced epitopes on the gp120 core in the HXBc2P 3.2 gp120 glycoprotein compared with the HXBc2 gp120 glycoprotein. Rearrangements of the second variable (V2) loop with respect to the CD4 binding site and associated epitopes were evident in comparisons of the two gp120 glycoproteins. Thus, the in vivo evolution of a neutralization-resistant virus involves conformational adjustments of the V2 and V3 variable loops with respect to the conserved receptor-binding regions of the gp120 core.

Abnormal collagen I to III distribution in the skin of patients with incisional hernia.

The surgical mesh-free repair of incisional hernias has to face recurrence rates of up to 50%. Apart from technical faults this is probably due to collagen metabolic disorders, known to play an important role in the development of inguinal hernia. In particular an altered ratio of collagen types I and III with an increase in collagen type III has been claimed to reduce the mechanical strength of connective tissues. Therefore, we investigated the content of collagen types I and III in the skin of patients with incisional hernia (n = 7) and recurrent incisional hernia (n = 5) in comparison to controls with healthy skin (n = 7) and normal skin scar (n = 7) both by immunohistochemistry and Western blot analysis. Both immunohistochemistry and Western blot analysis revealed a decrease in the ratio of collagen I/III due to a concomitant increase in collagen III. The patients with incisional hernias and with recurrent incisional hernias showed a ratio of 1.0 +/- 0.1 and 0.8 +/- 0.1, respectively, whereas the controls exhibit a ratio of 2.1 +/- 0.2 in healthy skin and of 1.2 +/- 0.2 in normal skin scar, respectively. The decrease was highly significant (p < 0.01) between the patients with either primary or recurrent hernia and the controls or the normal scar, as well as between controls and normal scar, whereas there was not any significant difference between primary and recurrent hernia (p > 0.05). Our data for the first time confirmed that the presence of incisional hernia is accompanied by impaired collagen synthesis in the skin. The decreased tensile strength of collagen type III may play a key role in the development of incisional hernias. Furthermore, it might explain the high recurrence rates of hernia repair by simple closure, as a repetition of the primarily failing technique, and the improvement by the additional use of alloplastic material.

Derivative spectrophotometric determination of praseodymium in rare earth mixtures with lomefloxacin.

Praseodymium forms a Pr(LMFX)(3) complex with lomefloxacin. In this paper, the absorption spectra of the complex has been investigated by applying conventional and derivative spectrophotometric methods. It was found that lomefloxacin could form a stable complex with praseodymium in the pH 6.5-8.5 media. The absorption intensity of the complex is 4.5-fold more than PrCl(3). Using the second derivative spectra, the sensitivity is 7.4 times higher for Pr than in the normal method (zero derivative spectra). The second derivative spectrophotometry for determination of praseodymium in the presence of other rare earths has been developed. The calibration curves were linear in the range of 3.5-65 mug ml(-1) for Pr. The detection limit is 0.85 mug ml(-1). The method is satisfactory for the determination of praseodymium in mixed rare earths.

Expression and regulation of glucokinase in rat islet beta- and alpha-cells during development.

Glucokinase (GK) is the rate-limiting enzyme in the glycolytic pathway of the beta-cell and, even in the rat fetus at 22-days gestation, immediately before birth, acts as a sensor of glucose influencing the rate of glucose utilization. However, when GK first appears in islets during beta-cell development is unknown. Whether GK is expressed in fetal glucagon-producing cells is also unknown. To determine this information, fetal rat islets were examined at 16-, 18-, and 22-days gestation. GK was identified immunocytochemically in both beta- and alpha-cells at all these ages, with the number of GK immunoreactive cells positively correlated to the fetal age from 16-22 days. Western blot analysis of islet protein extracts demonstrated the presence of GK, at 52 kDa, at 16 days and thereafter. To determine whether glucose had any effect on regulation of GK biosynthesis, fetal islets were cultured in medium containing a wide range of concentrations of glucose for 7 days. The amount of GK protein was significantly decreased in low concentrations of glucose and augmented at high concentrations. In conclusion, GK was expressed in both beta- and alpha-cells in fetal rat islets during development. GK is an integral part of the function of both of these cells at all stages in the development of the fetal islet.

Expression of the extracellular matrix proteins collagen I, collagen III and fibronectin and matrix metalloproteinase-1 and -13 in the skin of patients with inguinal hernia.

Although abnormal collagen metabolism has been ascribed an important role in the high recurrence rates after surgical hernia repair, knowledge on tissue sampled in the region affected by inguinal hernias is poor. In the present study, we determined collagen type I and type III in the skin of adult patients with indirect and direct inguinal hernias by both immunohistochemistry and Western blot analysis. In addition, we quantified the immunohistochemical expression of fibronectin and matrix metalloproteinase (MMP)-1 and -13. The results indicated that the ratio of collagen type I/III was significantly decreased in the skin of patients with either indirect (n = 9) or direct hernia (n = 7), with a concomitant increase in collagen type III (p < 0.001 vs. controls, n = 7, without affection of the inguinal region). There was no significant difference between patients with indirect and direct hernia (p > 0.05). MMP-13 was not expressed in any of the skin samples investigated, whereas MMP-1 was found in the epidermis. Fibronectin was predominantly detected at the epidermal-dermal junction. MMP-1, MMP-13 and fibronectin levels were significantly different between patients and controls (p > 0. 05). We conclude that in contrast to the unchanged expression of fibronectin and MMP-1 and MMP-13, the decreased ratios of collagen tpye I/III with the basically increased amount of collagen type III could be of significant importance for the pathophysiology of hernias. The specific ratio collagen I/III probably reflects the altered structural integrity and mechanical stability of the connective tissue in both indirect and direct hernias. Moreover, our findings stress that hernias should be regarded as the manifestation of a systemic disease in the inguinal region with a genetic background, explaining the high recurrence rates after repeated suture repair, as well as the usefulness of surgical meshes in this clinical setting.