[Impact of different obesity patterns on coronary microvascular function in male patients with non-obstructive coronary artery disease].

Objective: This study sought to investigate the impact of different obesity patterns on coronary microvascular function in male patients with non-obstructive coronary artery disease. Methods: We retrospectively analyzed clinical data of male patients diagnosed with suspected coronary microvascular dysfunction (CMD) in the First Hospital of Shanxi Medical University between December 2015 and August 2021. All patients underwent the one-day rest and stress 13N-ammonia positron emission tomography myocardial perfusion imaging. Overall obesity was defined by body mass index (BMI) ≥28 kg/m2 and abdominal obesity was defined by waist circumference ≥90 cm. Hyperemic myocardial blood flow (MBF)<2.3 ml·min-1·g-1 or coronary flow reserve (CFR)<2.5 were referred as CMD. All patients were grouped based on their BMI and waist circumference. MBF, CFR, the incidence of CMD, hemodynamic parameters, and cardiac function were compared among the groups. Results: A total of 136 patients were included. According to BMI and waist circumference, patients were categorized into 3 groups: control group (n=45), simple abdominal obesity group (n=53) and compound obesity group (n=38). Resting MBF did not differ between groups (F=0.02,P=0.994). Compared with the control group, hyperemic MBF was significantly lower in the simple abdominal obesity and compound obesity groups ((2.82±0.64) ml·min-1·g-1, (2.44±0.85) ml·min-1·g-1 and (2.49±0.71) ml·min-1·g-1, both P<0.05, respectively). Hyperemic MBF was comparable among the groups of patients with obesity (P=0.772). CFR was significantly lower in the simle abdominal obesity group compared with the control group (2.87±0.99 vs. 3.32±0.62,P=0.012). Compared with the control group, CFR tended to be lower in the compound obesity group (3.02±0.91 vs. 3.32±0.62,P=0.117). The incidence of CMD was significantly higher in both the simple abdominal obesity and compound obesity groups than in the control group (62.3%, 52.6% vs. 22.2%, both P<0.01, respectively). Waist circumference was an independent risk factor for male CMD (OR=1.057, 95%CI: 1.013-1.103, P=0.011). Conclusions: In male patients with non-obstructive coronary artery disease, abdominal obesity is associated with decreased coronary microvascular function. Male patients with simple abdominal obesity face the highest risk of CMD.

A study of microRNA-223 in evaluating platelet reactivity in patients with acute ischemic stroke.

To investigate the relationship between plasma microRNA-223 expression and platelet reactivity in patients with acute ischemic stroke (AIS) and to evaluate its predictive value in clopidogrel resistance or high on-treatment platelet reactivity (HTPR). A total of 120 patients with acute ischemic stroke were screened in this study, and 60 patients were included in the acute ischemic stroke group according to the inclusion criteria and platelet reactivity after clopidogrel treatment. control group was 60 non-ischemic stroke patients hospitalized. The levels of phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and adenosine diphosphate-induced platelet aggregation (ADP-PAg) in platelets were detected by flow cytometry. The expression level of plasma microRNA-223 was detected before and after clopidogrel treatment using quantitative real-time polymerase chain reaction (PcR). The AIS group was then divided into the clopidogrel non-HTPR and the clopidogrel HTPR groups based on the relative inhibition rate. We found that: 1) the VASP platelet reactivity index (PRI) was positively correlated with ADP-PAg; 2) before administration, the plasma microRNA-223 expression level and VASP-PRI were higher in the AIS group than in the control group; 3) after administration, the expression level of microRNA-223 was negatively correlated with VASP-PRI; 4) before and after treatment, the plasma microRNA-223 expression level in the clopidogrel HTPR group was lower than in the non-AIS patients; 5) before treatment, there was an interaction between the expression level of microRNA-223 in the plasma and the cYP2c19 loss-of-function (LOF) allele. The study showed that decreased plasma microRNA-223 expression levels in AIS patients indicate an increased risk of clopidogrel HTPR. carrying cYP2c19 LOF alleles may result in the microRNA-223 expression being more distinct. The combined detection of plasma microRNA-223 and cYP2c19 gene polymorphisms may be effective in predicting the occurrence of clopidogrel HTPR in patients with AIS.

[Prospective cohort study of relationship of triglyceride, fasting blood-glucose and triglyceride glucose product index with risk of hypertension].

Objective: To investigate the relationship of triglyceride (TG), fasting blood glucose (FPG) and triglyceride glucose product index (TyG) with the incidence of hypertension, and provide basic data for the prevention and treatment of hypertension in the population. Methods: A total of 23 581 individuals who met the research criteria in Jinchang cohort were selected as the research subjects, the Cox proportional hazard model was used to analyze the relationship of TG, FPG, and TyG with the risk of hypertension. A stratified analysis was conducted by sex. Results: After adjusting for confounding factors, compared with the normal TG group, the HR(95%CI) of the elevated TG margin group and the elevated group were 1.16 (1.01-1.34) and 1.49 (1.30-1.70), respectively in the total population. Among men, they were 1.13 (1.01-1.27) and 1.17 (1.06-1.30), and among women, they were 1.05 (0.88-1.26) and 1.06 (0.88-1.28). Compared with the normal FPG group, the HR (95%CI) of the FPG-impaired group were 1.29 (1.13-1.48) in the total population, 1.26 (1.08-1.48) in men and 1.59 (1.14-2.21) in women. Taking the lowest quartile array as a reference, the HR (95%CI) of the highest quartile array of TyG was 1.73 (1.45-2.07) in the total population, 1.32 (1.14-1.53) in men and 1.87 (1.37-2.54) in women. TG, FPG had a nonlinear dose-response relationship with the risk of hypertension, while TyG had a linear correlation with the risk of hypertension. Conclusions: Higher TG, FPG, and TyG levels are independent risk factors for the incidence of hypertension. People with higher TG, FPG and TyG are at high risk for hypertension, to which close attention should be paid in the prevention and treatment of hypertension.

[A nested case-control study on relationship of traditional and combined lipid metabolism indexes with incidence of diabetes].

Objective: To explore the relationship between lipid indicators and the incidence of diabetes, and to compare the diabetes prediction and identification power of traditional lipid combined lipid indicators, in order to explore the best alternative indicators for identifying and predicting diabetes. Methods: Based on the Jinchang cohort, a nested case-control study was conducted in 1 025 new cases of diabetes after excluding patients with malignant tumor and related endocrine, circulatory system disease, then an age (±2 years), gender matched 1∶1 control group of 1 025 cases was set to analyze the relationship between the incidence of diabetes and lipid parameters. Results: Among the traditional lipid parameters, the fourth quartile of TG, TC, and LDL-C indicated higher risks of developing diabetes, which was 14.00 times (95%CI: 9.73-20.15), 2.15 times (95%CI: 1.65-2.79) and 1.66 times (95%CI: 1.29-2.14) than that of the first quartile, respectively. The risk of developing diabetes indicated by the fourth quartile of HDL-C was 0.21 times than that indicated by the first quartile (95%CI: 0.15-0.28). In the combined lipid parameters, the fourth quartile of TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C indicated higher risks of developing diabetes, which was 14.86 times (95%CI: 10.35-21.34), 8.12 times (95%CI: 5.94-11.01), 5.85 times (95%CI:4.34-7.88) and 5.20 times (95%CI: 3.85-7.03) than that indicated by the first quartile, respectively. The areas under the ROC curve of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 0.76 (95%CI: 0.74-0.78), 0.59 (95%CI: 0.57-0.61), 0.67 (95%CI: 0.65-0.69), 0.57 (95%CI: 0.55-0.59), 0.77 (95%CI: 0.75-0.78), 0.73 (95%CI: 0.71-0.75), 0.69 (95%CI: 0.67-0.71) and 0.66 (95%CI: 0.64-0.68), respectively. The optimal diabetes predicting point cuts of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 1.40, 4.70, 1.28, 3.25, 1.17, 3.43, 2.46, and 3.58 mmol/L, respectively. Conclusions: Lipid metabolic disorder is a risk factor for diabetes. TG and TG/HDL-C are the good lipid metabolism indicators for the prediction of diabetic.

[Relationship of body mass index and blood pressure with diabetes: a nested case-control study].

Objective: To explore the relationship of body mass index and blood pressure with the incidence of diabetes in Jinchang cohort. Methods: We designed a nested case-control study, a total of 29 572 workers who had no history of diabetes in baseline survey in Jinchang cohort were selected as the study cohort from June 2011 to December 2013. After 2 year follow-up, 1 021 workers with first diagnosed diabetes were selected as the case group, after 1∶1 matching according to the same gender and age ±2 years among those without diabetes, circulatory system, or endocrine system diseases during the same follow-up period, 1 021 controls was selected and 2 042 subjects were finally included. We used multivariate conditional logistic regression model, additive interaction model and multiplicative interaction model to explore the relationship of body mass index and blood pressure with the incidence of diabetes. Results: After adjusting for factors such as occupation, alcohol use, family history of diabetes, hyperuricemia, hypercholesterolemia, hypertriglyceridemia, low-HDL cholesterolemia and high-LDL cholesterolemia, multivariate conditional logistic regression analysis showed that the risk of diabetes increased with body mass index and blood pressure. Hypertension and overweight/obesity had a multiplicative interaction on the incidence of diabetes. The risks of diabetes in men and women with hypertension and overweight/obese were 2.04 times (95%CI: 1.54-2.69) and 3.88 times (95%CI: 2.55-5.91) higher than those in men and women with normal body weight and blood pressure, respectively. In the combination of BMI and blood pressure, obese individuals with SBP≥160 mmHg were 4.57 times (95%CI: 2.50-8.34) more likely to have diabetes than those with normal BMI and SBP, obese individuals with DBP≥90 mmHg were 3.40 times (95%CI: 2.19-5.28) more likely to have diabetes than those with normal BMI and DBP. Conclusions: Overweight/obesity and hypertension can increase the risk of diabetes. Health education about body weight and blood pressure controls should be strengthened to reduce the risk of diabetes.

[Exploration of standardized sleep medicine fellowship training in Peking University Health Science Center].

Sleep Medicine is a clinical specialty covering the main categories of sleep-wake disorders. The formal training system for sleep medicine has been established in many countries, but not yet in China. The implementation of a pilot sleep medicine fellowship program was elaborated in this article, based on needs assessment of the relevant affiliated hospitals and teaching hospitals of Peking University Health Science Center. It was intended to draw on experiences to build up formal sleep medicine training system in future.

[Value of absolute quantification of myocardial perfusion by PET in detecting coronary microvascular disease in patients with non-obstructive coronaries].

Objective: To compare the incidence of coronary microvascular disease (CMVD) between patients with non-obstructive and obstructive coronary arteries. Methods: We retrospectively analyzed 97 patients with angina pectoris, who underwent the absolute quantitative PET examination of myocardial perfusion and coronary anatomy examination within 90 days. All patients were divided into two groups: non-obstructive group (72 cases, no stenosis ≥50% in all three coronary arteries) and obstructive group (25 cases, at least one coronary stenosis ≥50%; and at least one coronary stenosis<50%). Quantitative parameters derived from PET including rest myocardial blood flow (RMBF), stress myocardial blood flow (SMBF), coronary flow reserve (CFR) and cardiovascular risk factors were compared between the two groups. CMVD was defined as CFR<2.90 and SMBF<2.17 ml·min(-1)·g(-1). Results: Incidence of CMVD was significant higher in the non-obstructive coronary arteries of the obstructive group than in the non-obstructive coronary arteries of non-obstructive group (47.1% (16/34) vs. 25.5% (55/216), χ(2)=6.738, P=0.009) while incidence of CMVD was similar between non-obstructive and obstructive patients ((44% (11/25) vs. 33.3% (24/72), χ(2)=0.915, P=0.339). RMBF ((0.83±0.14) ml·min(-1)·g(-1) vs. (0.82±0.17) ml·min(-1)·g(-1)), SMBF ((2.13±0.60) ml·min(-1)·g(-1) vs. (1.91±0.50) ml·min(-1)·g(-1)) and CFR (2.59±0.66 vs. 2.36±0.47) were similar between the two groups (all P>0.05). Conclusions: CMVD can occur in non-obstructive coronary arteries in both patients with non-occlusive coronary arteries and patients with obstructive coronary arteries. Prevalence of CMVD is significantly higher in patients with obstructive coronary arteries than in patients with non-obstructive coronary arteries. The CMVD severity is similar between the two groups.

CT and MRI studies of hepatic angiosarcoma.

AIM: To analyse the computed tomography (CT) and magnetic resonance imaging (MRI) manifestations of hepatic angiosarcoma. MATERIALS AND METHODS: Nineteen patients with hepatic angiosarcoma underwent preoperative abdominal unenhanced and contrast-enhanced CT (11 cases) or (eight cases) MRI. RESULTS: The results of a coagulation examination showed varying degrees of abnormalities in 12 (63.16%) cases (most were prolonged prothrombin time and an increased proportion of prothrombin time), which were the most common abnormalities on the laboratory tests. Unenhanced CT of the lesions showed homogeneous or heterogeneous hypointense with hyperintense haemorrhagic lesions, contrast-enhanced CT was performed for six cases (6/11, 54.5%) with centripetal heterogeneous filling. All lesions showed heterogeneous intensity at MRI, including heterogeneous hypointense T1WI and homogeneous or heterogeneous hyperintense T2WI. Haemorrhage lesions showed higher hyperintensity with spot or patchy signals. Centripetal enhancement was found in six cases using contrast-enhanced imaging. Flaky patches of contrast enhancement were seen in the lesions. CONCLUSION: The CT and MRI features of most of the hepatic angiosarcomas in the present study were relatively characteristic: the border of the mass was indistinct, the density was heterogeneous, and haemorrhage was frequently seen, with secondary calcification in a few cases, whereas enhanced imaging showed typical centripetal heterogeneous enhancement. In addition, highly malignant angiosarcoma could not be enhanced.

[Studies on the serum types and identification efficiency on Diarrheagenic Escherichia coli isolated from diarrhea patients, in Zhejiang province].

Objective: To investigate the serotypes of Diarrheagenic Escherichia coli (DEC) isolated from diarrheal patients in Zhejiang province and to explore the identification efficiency of serological screening methods. Methods: Serological agglutination tests were carried out in 696 strains of DEC (through the identification of virulence genes) which were selected from the Infectious Diarrhea Pathogen Monitoring Network Strain Bank of Zhejiang province, from July 2009 to June 2013. Results of virulence genes, serological identification and classification were compared. Results: Among the 696 isolates of DEC, O antigen type was identified in 288 (41.4%) isolates which belonging to 35 different 'O' serum types. H antigen was seen in 171 (24.6%) isolates and determined as having 21 types. The agglutination rates of EAEC, ETEC, EPEC and EHEC isolates were 31.9% (130/408), 70.6% (127/180), 31.5% (29/92) and 14.3% (2/14), respectively and belonged to 30, 18, 15 kinds of 'O' sero-groups, respectively. One EHEC isolate was identified as O157∶H7. Serum groups were diverse for EAEC and EPEC, while relatively concentrated on ETEC. Different types of DEC might belong to the same sero-group or type. Among the 74 strains of DEC available for classification serologically, 41 isolates were in consistent with virulence gene identification and another 33 strains were not. Conclusions: The sero-group/type of DEC strains in Zhejiang were varied. Based on the serological screening method alone, DEC classification might end in getting the wrong answer, thus we would recommend the use of virulence gene for the purpose of identification.

Isolating and confirming the Mudr­inserted flanking sequences of maize.

MuDR exhibits the highest transposition activity and insertional mutagenesis frequency in Mutator (Mu) family. If we isolate the MuDR­insertion­specific flanking sequences (MuDRFs), it will be crucial for using Mu element­mediated mutants. The MuDR­TAIL­PCR system was constructed and optimized using a combination of MuDR­TIR­nested specific primers and 12 arbitrary degenerate (AD) primers, modified reaction system and procedure and mutant DNA templates of 87 genotypes from M2 or M2:3 families created by crossing the W22::Mu line (active MuDR donor parent) from the UniformMu population with the Zong31 (Z31) line (recipient parent). Here 129 different MuDRFs were acquired by MuDR­TAIL­PCR, accounting for 86.60 % of the total mutant­specific agarose gel bands. In addition, we confirmed the authenticity of the non­redundant flanking sequence amplifications. The amplified non­redundant flanking sequences accounted for 65.12 % of the total MuDRFs, and 88.00 % of the non­redundant MuDRFs were inserted inside the genes. These results show that the MuDR­TAIL­PCR system that we developed can be used for specifically isolating MuDRFs.

First-principles study on electron transport of carbon dumbbells C60-C(n)-C60.

Electronic transport properties of carbon dumbbells, a new type of carbon hybrid nanostructures formed by connecting carbon atomic chains to two fullerenes C(60), are investigated by using nonequilibrium Green's functions in combination with the density-functional theory. Specifically, the transport properties as a function of the carbon chain length n are examined. An obvious metal-insulator-like oscillation has been achieved with the increase of the carbon chain length. When n is even, the device behaves as a metal. In contrast, when n is odd, it behaves as an insulator. It is quite different to the carbon chains directly sandwiched between metallic leads where the low conductance states are observed for even n while the high conductance states are observed for odd n. Such a difference arises from the screening effect of C(60)s.

Preparation and characterization of nanostructured Ni(OH)2 and NiO thin films by a simple solution growth process.

Nanostructured Ni(OH)2 thin films were prepared by a simple solution growth process with F(-) and NH3 used as Ni2+ coordination agents, and ammonia hydroxide solution used as OH(-) supplier to accelerate the hydrolyzation of nickel complex species. The results showed Ni(OH)2 thin films were constructed mainly with hexagonal beta-Ni(OH)2 nanorods; the F(-) and NH3 in reactive solutions played important roles in the film growth process; and solution pH had great influence on the morphologies of thin films, which was explained by the competition of Ni(OH)2 nucleation and growth in solutions. NiO crystallinity thin films were obtained by annealing Ni(OH)2 thin films at 400 degrees C for 2 h and the morphologies of the Ni(OH)2 thin films were sustained well during the annealed process.

[P53 delta 37 protein exhibits 3'-5' exonuclease activity].

Mummenbrauer et al. (1996) found that P53 protein exhibits 3'-5' exonuclease activity. This exonuclease activity is intrinsic to wildtype P53 protein, dependent on Mg2+, and it can be inhibited by addition of 5 mmol/L nucleoside monophosphates. In the present study, we intended to know whether mutated P53 protein--P53 delta 37 has this 3'-5' exonuclease activity or not. The results reveal that P53 delta 37 also has 3'-5' exonuclease activity. It has more protein and more exonuclease activity, but this activity can not be inhibited by guanine monophosphate. There are many processes related to exonuclease activity in mammalian cells; for example, DNA replication, DNA recombination and DNA repair. The exonuclease activity of P53 delta 37 protein may be important in these processes.

Maintenance of beta-cell function and survival following islet isolation requires re-establishment of the islet-matrix relationship.

Islet transplantation is associated with a high rate of early graft failure, a problem that remains poorly understood. It is probable that the destruction of the islet microenvironment and loss of tropic support that occur during isolation lead to compromised survival. The purpose of this study was to determine the role of matrix-integrin interactions on beta-cell survival and function following islet isolation. Canine islets were obtained by conventional methods. Immediately after isolation, the peri-insular basement membrane (BM) was absent. The ability of islets maintained in suspension culture to attach to a collagen matrix declined progressively over 6 days. Attachment could be blocked by an arginine-glycine-aspartate (RGD) motif-presenting synthetic peptide, thereby implicating an integrin-mediated process. Characterization of cell surface integrins by immunocytochemistry (ICC) demonstrated that the expression of integrins alpha3, alpha5 and alphaV diminished during the culture period. This change was coincident with both a decrease in beta-cell function (proinsulin gene expression, islet insulin content and stimulated insulin release) and a rise in beta-cell death from apoptosis, as determined by in situ cell death detection (TUNEL) assay. These adverse events were prevented or delayed by exposure of islets to matrix proteins. In conclusion, routine islet isolation disrupts the cell-matrix relationship leading to a variety of structural and functional abnormalities, including apoptotic cell death. These alterations can be diminished by restoration of a culture microenvironment that includes matrix proteins.

Pancreatic islet cell survival following islet isolation: the role of cellular interactions in the pancreas.

The purpose of this study was to characterize the trophic effect of pancreatic duct cells on the islets of Langerhans. Ductal epithelium and islets were isolated from hamster pancreata. In addition, duct-conditioned medium (DCM) was prepared from primary duct cultures that had been passaged twice to remove other cellular elements. Three experimental groups were then established: Group 1, 100 islets alone; Group 2, 100 islets+80 duct fragments; and Group 3, 100 islets in 25% DCM. All tissues were embedded in rat tail collagen for up to 12 days and the influence of pancreatic ductal epithelium on islet cell survival was examined. By day 12, 20.6+/-3. 0% (S.E.M.) of the islets cultured alone developed central necrosis, compared with 6.7+/-2.0% of the islets co-cultured with ducts and 5.6+/-1.5% of the islets cultured in DCM (P<0.05). The presence of apoptotic cell death was determined by a TdT-mediated dUTP-biotin nick end labelling (TUNEL) assay and by a specific cell death ELISA. DNA fragmentation in islets cultured alone was significantly increased compared with islets cultured either in the presence of duct epithelium or in DCM (P<0.05). More than 80% of TUNEL-positive cells were situated in the inner 80% of the islet area, suggesting that most were beta-cells. DCM was analysed for known growth factors. The presence of a large amount of IGF-II (34 ng/ml) and a much smaller quantity of nerve growth factor (4 ng/ml) was identified. When the apoptosis studies were repeated to compare islets alone, islets+DCM and islets+IGF-II, the cell death ELISA indicated that IGF-II produced the same beneficial result as DCM when compared with islets cultured alone. We conclude that pancreatic ductal epithelium promotes islet cell survival. This effect appears to be mediated in a paracrine manner by the release of IGF-II from cells in the ductal epithelium.

Characterization of integrin expression in islets isolated from hamster, canine, porcine, and human pancreas.

The reasons for the failure of clinical islet transplantation remain obscure. Islet isolation, however, exposes the islet to variety of cellular stresses, including disruption of the cell-matrix relationship, an event associated with apoptosis. The cell-matrix relationship is characterized by an interaction between cell surface integrin receptors and matrix molecules of the surrounding basement membrane (BM). The purpose of this study was to characterize integrin expression and the distribution of the peri-insular BM in human, porcine, canine, and hamster pancreas, and after routine islet isolation. Whereas islets in the porcine pancreas do not have a demonstrable BM, islets in the human, canine, and hamster pancreas have an almost continuous BM with very little direct exocrine to endocrine cell-cell contact. After islet isolation, the BM was destroyed, only to be reestablished during the period of culture. In the pancreas of all four species, integrin alpha3 was expressed only on islet cells, and integrin alpha5 was present on islet cells as well as on acinar, centroacinar, and duct cells. Integrin alphaV was detected only in human and canine pancreas. Integrin beta1 was demonstrated only in the human pancreas. In isolated islets, integrin alpha3, alpha5, and alphaV expression decreased during the culture period and the intensity of the staining was observed to be coincident with the distribution of the BM. In summary, this is the first report of integrin expression in hamster, canine, porcine, and human islets. After islet isolation, the altered islet cell-matrix relationship is reflected both in the decrease in integrin expression and in the destruction of the peri-insular BM. These profound changes will need to be considered as the process of islet isolation for transplantation is refined. (J Histochem Cytochem 47:499-506, 1999)

Distinct regions of frequent loss of heterozygosity of chromosome 5p and 5q in human esophageal cancer.

Loss of heterozygosity (LOH) studies reported thus far suggest that tumor suppressor loci on chromosome 5q are important in esophageal cancer (EC) while little is known about the involvement of chromosome 5p. To investigate the potential existence of tumor suppressor gene(s) on chromosome 5 contributing to the development of EC, we performed LOH studies using a total of 24 polymorphic markers spanning the entire chromosome 5. Seventy primary esophageal cancers were microdissected and allelic deletions were detected by polymerase chain reaction (PCR)-single strand conformation polymorphism or by microsatellite analysis. LOH was observed in at least 1 of the loci in 47 of 70 (67%) esophageal tumors. Initially, 40 tumors [24 squamous cell carcinomas (SCC) and 16 adenocarcinomas (ADC)], each with matched histologically normal esophageal mucosa, were analyzed at 15 marker loci on 5p and 5q. A novel locus, D5S667 on 5p15.2, exhibited the highest frequency of LOH (44%) in these tumors along with another previously reported region of frequent deletion, irf-1 (5q31.1). In a series of 30 additional EC tumors (11 SCC and 19 ADC), a detailed LOH analysis of chromosome 5p15.2 region was conducted using 10 additional polymorphic markers, which mapped the frequently deleted region within 1 cM. Overall, LOH at the D5S667 locus was observed more frequently in SCC than in ADC (62% vs. 23%, p = 0.01). This significant rate of LOH of a distinct region of chromosome 5p implicates the existence of a putative tumor suppressor gene locus involved in EC.

Expression of gastrin and transforming growth factor-alpha during duct to islet cell differentiation in the pancreas of duct-ligated adult rats.

In adult rats islet cell neogenesis can be stimulated by partial duct ligation. Duct to islet cell differentiation is thought to be regulated by growth factors such as gastrin and transforming growth factor-alpha (TGF alpha). To test this hypothesis, we examined the expression of gastrin and TGF alpha at the mRNA and protein level in pancreatic tissue following partial duct ligation. Pancreatic specimens were investigated on days 3, 5, 7 and 14 after duct ligation by means of non-isotopic in situ hybridization, immunocytochemistry and Western blotting. Gastrin mRNA was strongly expressed in newly developed duct-like cell structures in the ligated tail portion of the pancreas before the period of pronounced islet cell neogenesis (days 5 and 7), and immunostaining for gastrin peptides was positive at days 5-7. In the non-ligated head portion and in control pancreases, gastrin was not expressed. Expression of TGF alpha was found to be increased in the ligated tail portion of the pancreas on day 3 and particularly on day 5, while there was no enhanced signal in the non-ligated part. Western blotting revealed two different TGF alpha isoforms (18 kDa and 42 kDa) in the ligated tail part and three isoforms (18 kDa, 24 kDa and 42 kDa) in the non-ligated head part and in untreated pancreases. The induction of gastrin and TGF alpha expression preceded the peak in the bromodeoxyuridine pulse labelling index of beta cells, known from a previous study to occur on day 7. We conclude that pancreas duct ligation induces the overexpression of gastrin and TGF alpha in the first days following ligation. Since ductal cells are known to give rise to endocrine cells after duct ligation, gastrin and TGF alpha may play a role as growth factors in islet neogenesis.

Beta-cell growth in adolescent and adult rats treated with streptozotocin during the neonatal period.

Regeneration of neonatal beta cells after subtotal streptozotocin (STZ)-induced destruction is incomplete but nevertheless leads to rapid remission of hyperglycaemia. To study the proliferative and functional capacity of regenerated beta cells in adolescent and adult rats after early beta-cell damage and to determine the time point after birth which is decisive for regeneration, beta-cell growth and metabolic capacity were analysed in rats treated during the neonatal period with STZ (100 micrograms/g body weight) and studied over 3 to 20 weeks. Using immunocytochemistry combined with morphometry we found that the regenerated beta cells continue to increase in number till week 6 of life, when they reached values of more than 50% of those of controls. After week 6, the regenerated beta cells had enlarged in size but failed to further increase their number, although their proliferative activity, determined by bromodeoxyuridine (BrdU) pulse labelling, was still higher at 6 and 10 weeks than that of normal rats. The inability of regenerated beta cells to further increase their number coincided with a deterioration of their function (week 10, male rats; week 20, female rats). When beta cells were destroyed on day 2 or 5 instead of the day of birth, regeneration of beta cells markedly decreased and the rats were already on the threshold of development of glucose intolerance at 3 weeks of age. We concluded that the partially regenerated beta-cell population in rats treated with STZ on the day of birth ceases to grow 10 to 20 weeks later. This growth arrest may be due to the sustained functional demand to which these beta cells are exposed in order to compensate for their reduced number. Beta-cell capacity for regeneration declines rapidly during the first days of life.

Duct- to islet-cell differentiation and islet growth in the pancreas of duct-ligated adult rats.

We investigated the growth of islet beta and alpha cells in adult rats which had undergone partial pancreatic duct ligation. Whereas the non-ligated head portion of the pancreas remained unaffected in terms of histology and cell population dynamics, the ligated tail part of the pancreas showed pronounced changes in histology and cell growth. These changes included replacement of exocrine acini by ductal complexes and significant growth of islet cells. Using immunocytochemistry and morphometry, we found that the beta-cell population had nearly doubled within 1 week and that a smaller, but also significant growth of the alpha-cell population had occurred. In addition, small islets and islet-cell clusters were more numerous in the pancreatic tail, indicating islet neogenesis. The bromodeoxyuridine (BrdU) pulse labelling index of beta and alpha cells increased five fold and threefold, respectively, in the tail. However, the observed beta-cell labelling index remained below 1% which was largely insufficient to explain the increased number of beta cells. This indicates that recruitment from a proliferating stem-cell compartment was the main source for the beta-cell hyperplasia. A tenfold-elevated BrdU labelling index (18%) was observed in the duct-cell compartment which was identified by specific immunostaining for cytokeratin 20. Transitional cytodifferentiation forms between duct cells expressing cytokeratin 20 and beta cells expressing insulin, or alpha cells expressing glucagon, were demonstrated by double immunostaining. Pancreatic duct ligation also induced the expression of the beta-cell-specific glucose transporter type 2 (GLUT-2) in duct cells, indicating their metaplastic state. We concluded that in this adult rat model, the proliferation and differentiation of exocrine duct cells represents the major mechanism of endocrine beta-cell neogenesis. Our study thus demonstrates that in normal adult rats islet-cell neogenesis can be reactivated by stimulation of pancreatic duct cells.