Caste-specific microRNA expression in termites: insights into soldier differentiation.

Eusocial insects have polyphenic caste systems in which each caste exhibits characteristic morphology and behaviour. In insects, caste systems arose independently in different lineages, such as Isoptera and Hymenoptera. Although partial molecular mechanisms for the development of eusociality in termites have been clarified by the functional analysis of genes and hormones, the contribution of microRNAs (miRNAs) to caste differentiation is unknown. To understand the role of miRNAs in termite caste polyphenism, we performed small RNA sequencing in a subterranean termite (Reticulitermes speratus) and identified the miRNAs that were specifically expressed in the soldier and worker castes. Of the 550 miRNAs annotated in the R. speratus genome, 74 were conserved in insects and 174 were conserved in other termite species. We found that eight miRNAs (mir-1, mir-125, mir-133, mir-2765, mir-87a and three termite-specific miRNAs) are differentially expressed (DE) in soldiers and workers of R. speratus. This differential expression was experimentally verified for five miRNAs by real-time quantitative PCR. Further, four of the eight DE miRNAs in soldier and worker termite castes were also differentially expressed in hymenopteran castes. The finding that Isoptera and Hymenoptera shared several DE miRNAs amongst castes suggests that these miRNAs evolved independently in these phylogenetically distinct lineages.

Phase I clinical trial of human vascular endothelial growth factor receptor 1 peptide vaccines for patients with metastatic renal cell carcinoma.

BACKGROUND: It is well known that renal cell carcinoma (RCC) represents one of the most immune-responsive cancers. Although the lack of defined antigens in RCC has hindered more specific vaccine development, research regarding vaccination therapy has been of special interest for the treatment of RCC for more than 30 years. METHODS: To evaluate the safety of the vascular endothelial growth factor receptor 1 (VEGFR1) peptide vaccination and its clinical outcomes, data from 18 metastatic RCC (mRCC) patients treated with VEGFR1 vaccine were collected. Toxicity assessments were performed. Clinical outcomes included assessment using CT scanning, magnetic resonance imaging or X-ray examination in accordance with the WHO Response Evaluation Criteria in Solid Tumors. RESULTS: No patient showed any toxicities of grade 3 or greater. Of the 18 patients, 2 patients showed a partial response during treatment. Stable disease for more than 5 months was observed in eight patients with a median duration of 16.5 months (4-32 months). At the time of the analysis in this study, six patients were alive with a median follow-up of 30 months (26-36 months). CONCLUSION: These results suggest that VEGFR1 peptide vaccine is safe and is recommended for further trials for patients with mRCC.

Development and evaluation of 'disaster preparedness' educational programme for pregnant women.

PURPOSE: The objective of this study is the development and evaluation of the usability of an educational programme that teaches disaster preparedness to pregnant women. METHODS: This intervention study examined an intervention group that attended an educational programme and a control group that did not. The subjects were pregnant women in their second trimester. The programme was developed with prior studies and evaluated by self-administered questionnaires that asked about disaster preparedness. The questionnaire was administered twice to the participants in both groups: to the intervention group just before the childbirth class and 1 month after the class, and to the control group at the time of their maternity examination and 1 month afterwards. Two hundred twenty-six members of the intervention group and 262 members of the control group responded to both questionnaires. Of these, 99 of the intervention group and 104 of the control group were primiparous without disaster experience, and the programme was evaluated by comparing these two groups. Effects due to the disaster experience were also analysed within the intervention group. RESULTS: Among primiparous without disaster experience, an intervention effect was found in items concerning awareness modification (five of six items) and behaviour modification (three of seven items). The intervention effect was particularly pronounced in a comparison of primiparous without disaster experience. CONCLUSIONS: An intervention effect was found among the pregnant women who took the programme. In particular, it was statistically significant among primiparous without disaster experience, which suggests that the programme should be shaped to reflect this subject demographic.

Genomic drift and copy number variation of chemosensory receptor genes in humans and mice.

Recent studies about the structural variation of genomic sequences have shown that there is a large amount of copy number variations (CNVs) of genes within species. Analyzing Redon et al.'s (2006) crude data on copy number variable regions (CNVRs), we previously showed that CNVs are particularly high for chemosensory receptor genes in human populations. In this paper, we reanalyzed the CNVs of these genes using more refined data by Perry et al. (2008). The results showed that the extent of CNVs is somewhat lower in this dataset than in the previous one, but that the extent is still substantial for olfactory receptor (OR), vomeronasal receptor (VR), and taste receptor (TR) genes. We also studied the CNVs for chemosensory receptor genes in mice, using CNVR data obtained from inbred strains. It was found that the extent of CNVs is quite substantial but is lower than that for human populations. However, because the mouse data came from inbred strains and might be biased, this conclusion should be regarded as tentative. Despite this reservation, the distribution of gene copy number for the OR gene family was approximately normal in both humans and mice, suggesting that genomic drift caused by random duplication and deletion of genes plays important roles in determining the evolutionary change of chemosensation.

Residents' awareness and behaviour regarding typhoon evacuation advice in Hyogo Prefecture, Japan.

BACKGROUND: When residents are confronted with disaster, it is often difficult for them to realize the danger and take protective action. In 2004, an evacuation advisory alert was issued on the approach of the season's 23rd typhoon in Japan, but only 5.1% of the residents actually evacuated. Therefore, we felt it necessary to elucidate the awareness and behaviours of residents during the period. AIMS: To clarify the awareness, behaviour and related factors of residents who were issued an evacuation advisory alert for the 2004 season's 23rd typhoon. METHODS: One questionnaire per one household was distributed to 2818 households in the area where the evacuation advisory alert was issued. FINDINGS: A total of 481 responses were returned (a response rate of 17.1%). Residents who evacuated made their decision because they felt the situation was dangerous; they recognized the extent of the danger. There was a pattern of agreement that it had been wise to do so. For those who didn't evacuate, many cited as the reason for their behaviour that their houses didn't flood. Non-evacuees also felt it was all right to stay at home and valued the merits of staying home. Related factors were housing structures, routine disaster-preparedness, a sense of personal danger and the impact of mass media news. CONCLUSIONS: Although the participation rate was only 17.1%, this study was successful in uncovering aspects of awareness and behaviour of residents in the designated area. It also provided insight into what is needed for future disaster-preparedness, equipment and education.

Mycelial glucoamylases produced by the thermophilic fungus Scytalidium thermophilum strains 15.1 and 15.8: purification and biochemical characterization.

Two strains (15.1 and 15.8) of the thermophilic fungus Scytalidium thermophilum produced high levels of intracellular glucoamylases, with potential for industrial applications. The isoform I of the glucoamylase produced by 15.1 strain was sequentially submitted to DEAE-Cellulose and CM-Cellulose chromatography, and purified 141-fold, with 5.45% recovery. The glucoamylase of strain 15.8 was purified 71-fold by CM- Cellulose and Concanavalin A-Sepharose chromatography, with 7.38% recovery. Temperature and pH optima were in the range of 50-60°C and 5.0-6.0, respectively, using starch and maltose as substrates. The glucoamylase of S. thermophilum 15.8 was more stable (t50 > 60 min) than that of S. thermophilum 15.1 (t50= 11-15 min), at 60°C. The glucoamylase activities were enhanced by several ions (e.g. Mn(2+) and Ca(2+)) and inhibited by ß- mercaptoethanol. The glucoamylase from 15.1 strain showed a Km of 0.094 mg/ml and 0.029 mg/ml and Vmax of 202 U/mg prot and 109 U/mg prot, for starch and maltose, respectively. The hydrolysis products of starch and maltose, analyzed by TLC, demonstrated glucose as end product and confirming the character of the enzyme as glucoamylase. Differences were observed in relation to the products formed with maltose as substrate between the two strains studied. S. thermophilum 15.8 formed maltotriose in contrast with S. thermophilum 15.1.

Regulation of donor T cells in the tolerant rats to graft-versus-host disease by FTY720 following small bowel transplantation.

AIMS: The potency of immunosuppression is a critical factor in small bowel transplantation (SBTx). FTY720 altered lymphocyte trafficking and prevented the donor T cells from migrating into target organs, resulting in the prolongation of recipient survival in acute graft-versus-host disease (GVHD) of SBTx. However, the effect of FTY720 on donor T cells in the chronic phase of GVHD following SBTx remains unclear. METHODS: Heterotopic SBTx was performed in a WF-to-F1 (WF x ACI) rat combination. Recipients were given FTY720 for 14 days after SBTx. The subpopulations of donor-derived T cells and the cytokine production in the target tissues were evaluated on postoperative day 150. RESULTS: FTY720 treatment significantly prolonged recipient survival over 150 days without any clinical signs of GVHD. The numbers of donor-derived CD4+ and CD8+ T cells in the peripheral blood, mesenteric lymph nodes, and Peyer's patches of recipients were maintained at low levels on postoperative 150, which were almost similar to the levels on postoperative day 14. In the host lamina propria, however, a significant higher number of donor T cells (CD4+, 18.4 +/- 4.3 x 10(4); CD8+, 13.9 +/- 3.6 x 10(4)) were still observed on postoperative day 150. Production of interferon-gamma was significantly reduced in target tissues by FTY720 treatment both in the acute and chronic phase. However, interleukin-4 and interleukin-10 production, which was significantly higher on day 14, returned to the level of naive rats in the chronic phase. CONCLUSIONS: A 14-day treatment of FTY720 induced tolerance in our SBTx model. Down-regulation of both Th1 and Th2 immune response was observed in the chronic phase.

Prostate-specific transcription factor hPSE is translated only in normal prostate epithelial cells.

We recently cloned a novel transcription factor gene, hPSE, which belongs to the Ets gene family. hPSE mRNA was expressed specifically in prostate glandular epithelial cells and also in the human prostate carcinoma cell lines PC-3 and LNCaP. On the other hand, on immunoblot analysis with anti-hPSE antiserum, hPSE protein was detected only in human prostate tissue samples and not in PC-3 or LNCaP culture cells. Immunohistochemistry and in situ hybridization analysis revealed that hPSE protein was translated in normal prostate glandular epithelial cells, but not in carcinoma cells with hPSE transcripts. These findings suggest that expression of hPSE is regulated translationally in prostate epithelial cells and that hPSE protein is a candidate for a marker distinguishing normal cells from cancer cells in the prostate. It appeared that the 5'- and 3'-untranslated regions of hPSE transcripts might be necessary for translational control of hPSE, on the basis of results of transfection analysis in non-prostate lineage cells (HEK-293) using some deletion mutants of hPSE cDNA.

Midterm outcome of total hip arthroplasty for rapidly destructive coxarthrosis.

PURPOSE: To compare the midterm outcome in 12 women who underwent total hip arthroplasty (THA) for rapidly destructive coxarthrosis (RDC) and in 12 controls who underwent THA for osteoarthritis. METHODS: Records of 12 women aged 50 to 80 (mean, 72.3) years who underwent THA for RDC after a mean of 9 (range, 4-11) months since symptom onset were reviewed. They were compared with 12 age-and sex-matched controls who underwent THA for primary or secondary osteoarthritis. Acetabular bone deficiency of the 12 RDC patients was classified as type I (n=7), type II (n=4), or type III (n=1). Type I was treated with cementless THA, and types II and III were treated with THA with a cemented acetabular component. The femoral component was cementless. Pre- and post-operative Harris Hip Score was assessed. Radiographs of the hip were evaluated for implant migration, osteolysis, and periprosthetic radiolucency in the acetabulum and proximal femur. RESULTS: The 12 women who underwent THA for RDC and the 12 controls who underwent THA for osteoarthritis were comparable in terms of pre-, intra-, and post-operative parameters. After a mean follow-up of 9.3 years, the mean Harris Hip Score improved from 38.3 to 81.1 in RDC patients and from 43.6 to 84.2 in controls (p=0.13). One RDC patient had dislocation but did not require revision surgery. One RDC patient developed a radiolucent line <2 mm in zones 1 and 7 of the femoral component, but no migration occurred. No patient had progression of bony destruction, loosening, osteolysis, migration, or radiolucency of the acetabular component. CONCLUSION: Despite the rapid destruction of the acetabulum and femoral head in RDC patients, cemented or cementless THA achieved a good midterm outcome comparable to that for patients with primary or secondary osteoarthritis.

'Inverse' substrates for butyrylcholinesterase.

1. 'Inverse'-type substrates for butyrylcholinesterase (acylcholine acylhydrolase, EC 3.1.1.8), i.e., p- and o-nitrophenyl esters of (3-carboxypropyl)-trimethylammonium iodide, (4-carboxybutyl)trimethylammonium iodide and (5-carboxypentyl)trimethylammonium iodide were prepared, and their kinetic parameters for butyrylcholinesterase-catalyzed hydrolysis were determined. 2. The hydrolysis of these 'inverse'-type substrates were found to proceed through specific binding with the enzyme and efficient production of acyl enzyme intermediates, a pathway essentially identical with that followed by choline esters, normal type substrates.

Somatostatin release from the isolated, perfused diabetic rat pancreas: inverse relationship between pancreatic somatostatin and insulin.

The changes in pancreatic somatostatin content and release were studied in streptozotocin (STZ)-diabetic rats. Male Wistar rats were treated with a graded dose of STZ (group I, 0; II, 25; III, 50; IV, 75 mg/kg), which produced various grades of diabetic rats four weeks later. The pancreatic somatostatin content increased in proportion to the dose of STZ (I, 189 +/- 31; II, 222 +/- 20, III, 343 +/- 4; IV, 515 +/- 36 ng/g wet wt), while graded reductions of insulin content were observed. Significant increases in glucagon content were found only in groups III and IV. Pancreatic somatostatin release increased during arginine infusion (19.2 mM) dose dependently, (I, 543 +/- 36; II, 946 +/- 64; III, 1229 +/- 55; IV, 2186 +/- 150 pg/15 min), and it correlated with the graded decreases of insulin release. The glucagon release induced by arginine, however, did not change significantly. These results indicate that pancreatic somatostatin content and release increased in STZ-diabetic rats in proportion to the degree of insulin deficiency.

Reversal of the enhanced somatostatin release from the isolated, perfused diabetic rat pancreas after the amelioration of diabetes by whole pancreas transplantation.

To investigate the pancreatic endocrine function in streptozotocin-diabetic rats before and after the whole pancreas was transplanted, pancreatic insulin, glucagon, and somatostatin content and release were measured. Highly inbred Lewis male rats were divided into the following three groups: normal control rats; streptozotocin-induced-diabetic rats; and streptozotocin-diabetic rats transplanted with whole pancreas. Studies in vivo revealed normalization of elevated blood glucose and marked improvement of the impaired arginine-induced plasma insulin release by the transplantation of a healthy pancreas into the diabetic rats. Neither basal nor arginine-induced plasma glucagon levels in the diabetic rats were significantly different from the normal group, but significantly higher plasma glucagon levels were found in the transplanted rats. Studies in vitro using the isolated perfused rat pancreas revealed a significant increase of somatostatin release from the diabetic pancreas, with a marked reduction of insulin release and almost normal glucagon release. In the transplanted rats, on the other hand, arginine-induced somatostatin release from the host pancreas was reduced to normal without a significant change in insulin or glucagon release. In addition, the endocrine function of the graft remained normal in the transplanted rats. Pancreatic somatostatin release, thus, appears to be effected by changes in circulating insulin, since pancreatic transplantation effectively corrects the circulating insulin level.

Reversal of increased gastric somatostatin in streptozotocin-diabetic rats by whole pancreas transplantation.

Changes in both the content and the release of gastric somatostatin after amelioration of streptozotocin (SZ)-induced diabetes by whole pancreas transplantation were investigated in the present study. Highly inbred male Lewis rats were divided into three groups: normal, control rats; SZ-induced diabetic rats; and SZ-diabetic rats after whole pancreas transplantation. Fundic as well as antral somatostatin content in the streptozotocin-diabetic rats was significantly increased compared with the controls. Whole pancreas transplantation in SZ-diabetic rats markedly lowered the increased somatostatin content both in the fundus and the antrum. On the other hand, the exaggerated somatostatin release induced by glucagon from the isolated, perfused stomach observed in the SZ-diabetic rats was reduced to the level of normal rats by whole pancreatic transplantation. From these results, it is concluded that the hyperfunction of gastric D-cells in the SZ-diabetic rats is reversed by transplantation of whole pancreas.

Somatostatin release from isolated perfused rat pancreas. Possible role of endogenous somatostatin on insulin release.

In order to elucidate the role of endogenous somatostatin in the control of insulin and glucagon secretion, glucagon- or insulin-induced somatostatin release from the isolated perfused rat pancreas was studied. Immunoreactive somatostatin was persistently released for 60 min in response to perfusion by 5.5 mM glucose at concentrations ranging between 10 and 15 pg/ml. The addition of glucagon (10(-8), 10(-7), and 10(-6) M) caused a dose-related increase of somatostatin release. In contrast, insulin release, especially its first phase, was suppressed when concentrations of glucagon were increased. The addition of insulin (10(-7) M and 10(-6) M) had no significant effect on somatostatin and glucagon release. These results raise the possibility that endogenous somatostatin and glucagon together regulate insulin secretion, suggesting a close interrelationship between insulin, glucagon, and somatostatin secretion within the islet.

Beneficial effects of pancreas transplantation: regeneration of pancreatic islets in the spontaneously diabetic Torii rat.

AIMS: Type 2 diabetes is characterized by a combination of insulin resistance and pancreatic beta-cell dysfunction. Although pancreas transplantation (PTx) is mainly performed in patients with type 1 disease, both clinical and experimental data have demonstrated that PTx improves insulin sensitivity in type 2 diabetic recipients. However, it remains unclear whether PTx has the potential to induce islet neogenesis in a recipient's native pancreas. METHODS: Nondiabetic 10-week-old and diabetic (defined as blood glucose level >250 mg/dL) 25-week-old (average onset age of diabetes) male spontaneously diabetic Torii (SDT; RT1(a)) rats served as donors and recipients, respectively. RESULTS: In nontreated control SDT rats, beta-cell mass gradually decreased and blood glucose levels progressively increased (>600 mg/dL after 40 weeks of age). In PTx rats, however, the onset of diabetes was significantly delayed (>47.5 +/- 18.2 [graft age] versus 25.2 +/- 3.9 weeks in control rats). On immunohistochemical staining, insulin-secreting islets were observed in the naive pancreata of 40-week-old recipients with PTx (PTx40w), whereas no islets were found in 40-week-old control SDT rats. Moreover, the islets in the native pancreata of PTx40w recipients were located close to ductal structures, and PDX-1 (pancreatic duodenal homeobox-1)-positive cells were more clearly visible. These results indicate the possibility of beta-cell regeneration in the recipient native pancreas by avoiding glucose toxicity under normoglycemic condition achieved by PTx. CONCLUSIONS: Pancreas transplantation has beneficial effects on impaired islet, inducing regeneration in the spontaneously diabetic Torii rat.

Effect of tolbutamide on insulin, glucagon, and somatostatin release from the diabetic rat pancreas with special reference to glucose concentration.

The effects of tolbutamide on insulin, glucagon, and somatostatin secretion were investigated in the isolated perfused pancreas from normal and diabetic rats under low (30 mg/dl), normal (100 mg/dl), and high (300 mg/dl) glucose conditions. In the normal rat pancreas, tolbutamide-induced insulin release was increased when the glucose concentration in the perfusion medium was increased from 30-300 mg/dl. Tolbutamide had an inhibitory effect on glucagon release at the low (30 mg/dl) glucose concentrations, although a stimulatory effect was observed under normoglycemic conditions. The total amount of somatostatin secretion above baseline during tolbutamide infusion was higher under the normal glucose than under the low glucose condition. However, further augmentation of somatostatin release was not found at the high glucose concentration. In the diabetic rat pancreas, insulin release was diminished and tolbutamide-induced somatostatin release was enhanced with increasing glucose concentrations. Glucagon release was stimulated at the normal glucose concentration, but inhibited temporarily at the high glucose concentration. The maximum somatostatin response in the early phase was significantly decreased in the diabetic pancreas under low and normal glycemic conditions, when expressed as an incremental change (percentage) above baseline. From these results, one can conclude: (1) tolbutamide has a stimulatory effect on the pancreatic D cell in both the normal and diabetic pancreas; (2) the early response of somatostatin is decreased in the diabetic pancreas, except under conditions of high glucose concentration; and (3) the pancreatic A cell response to tolbutamide was not uniform and was quite different from the response of the D cell.

Importance of donor-derived lymphocytes in the protection of pancreaticoduodenal or islet grafts from recurrent autoimmunity: a role for RT6+NKR-P1+ T cells.

BACKGROUND: A rat pancreas transplantation model with insulin-dependent diabetes mellitus (IDDM) recurrence was established using a Wistar-Furth (WF; RT1u, RT6.2) rat as a donor and diabetes-prone (DP; RT1u, rt6.1 gene carrier) BioBreeding rat as a recipient. Interestingly, NKR-P1+TCRalphabeta+ (NKT) cells have recently been reported to have immunoregulatory functions in preventing autoimmune diabetes. The purpose of this study was to specifically examine the contribution of NKT cells in the prevention of IDDM recurrence. METHODS: Graft survivals with or without anti-intercellular adhesion molecule-1/leukocyte function-associated antigen-1 monoclonal antibodies were examined comparing pancreaticoduodenal (PD) transplantation with islet transplantation or pancreas-alone transplantation excluding duodenum and peripancreatic lymph nodes, in an IDDM recurrent model. The cells of the spleen were analyzed by flow cytometry (including intracellular interleukin (IL)-4 analysis), and serum cytokine levels (IL-4 and interferon-gamma) were determined by enzyme-linked immunosorbent assays (ELISA). RESULTS: Only those DP recipients transplanted with PD grafts with monoclonal antibody treatment were free from IDDM. Flow cytometric analyses of spleen cells showed that NKT cells in them, compared with those in the recurrent DP recipients (mean <7%), increased significantly (13.7+/-3.1% in the total splenic T cells), most of which (85.9+/-4.3%) were derived from the donor (RT6.2+). The absolute number of RT6+NKT cells significantly increased in the nonrecurrent DP recipients, whereas that of RT6-NKT cells was similar with those of the other recurrent DP recipients. These RT6+NKT cells were predominantly CD4+ and showed significantly more expressions of intracellular IL-4 than the other T cells. By ELISA, serum interferon-gamma was not detectable (< 13 pg/ml) in any of the rats. However, IL-4 was detected at 111.6+/-47.8 pg/ml only in the nonrecurrent DP recipients. CONCLUSIONS: Unlike islet or pancreas-alone transplants, NKT cells, especially RT6+NKT cells derived from PD grafts, may have an important immunoregulatory function of preventing IDDM recurrence, involving a Th2 deviation.

Restoration of immune abnormalities in diabetic BB rats after pancreas transplantation. I. Macrochimerism of donor-graft-derived RT6+ T cells responsible for restoration of immune responsiveness and suppression of autoimmune reaction.

Diabetes-prone (DP) BB rats (RT1(u), RT6.1) spontaneously develop insulin-dependent diabetes mellitus (IDDM) and the disease manifestation resembles that in human IDDM. DP rats are immunodeficient with severe T lymphocytopenia due to the absence of T cells expressing the RT6 differential alloantigen, which have immunoregulatory functions. MHC- and non-MHC-compatible Wistar Furth (WF; RT1(u), RT6.2) pancreases were transplanted into DP rats. WF pancreas grafts were destroyed by IDDM recurrence (insulitis), but not by rejection, with a mean survival time of 65.3 +/- 21.7 days. To prevent the recurrence of IDDM in the grafts, monoclonal antibodies to intercellular adhesion molecule-1 and leukocyte function-associated antigen-1 were administered. WF pancreas grafts were indefinitely accepted (>108.0 +/- 26.8 days) in monoclonal antibody-treated DP recipients. The number of T cells was increased and cellular immune responses restored only in the DP rats that had accepted grafts. The increased number of T cells was due to the peripheral appearance of donor-type RT6.2+ T cells, which represented 34.3 +/- 7.0% of total splenic T cells. The cytotoxicity of splenic T cells to WF islet cells was suppressed in the presence of RT6+ T cells in vitro. These findings demonstrated that stable macrochimerism of donor-derived RT6+ T cells could restore the immune responses and prevent the recurrence of IDDM in the DP recipients.

Cardiac heterotransplantation. Morphological and immunohistological studies.

A vascularized heterograft model using outbred strains of animals was developed by transplanting mouse hearts heterotopically into rats. With this species desparity rapid but not immediate graft rejection was observed, with a predictably narrow range of graft survival times. Morphological and immunohistological studies showed early deposition of fibrinogen and vascular and myocardial inflammation without prominent or consistent localization of either IgG or C3. Later more extensive changes were observed, and deposition of IgG and C3 were more prominent in the grafts. Pretreatment of the recipient with cyclophosphamide alone or cyclophosphamide plus antigen prolonged graft survival; however, no statistically significant difference was noted between these groups. Morphological and immunohistological alterations preceded clinical rejection, and tissue injury appeared to be mediated by humoral and cellular immune mechanisms and by the coagulation system. This model is potentially useful for the study of heterotransplantation.

Generation of nitric oxide as a rejection marker in rat pancreas transplantation.

In clinical pancreas transplantation, no reliable marker for the early diagnosis of acute rejection has been reported. This is one reason why the graft survival rate of pancreas transplantation alone is much lower than that of other organs, such as hearts, livers, and kidneys. We designed an experiment to investigate acute rejection of pancreas allografts in hyperglycemic rats by measurement of blood glucose levels and nitric oxide (NO) products (nitrite plus nitrate, and nitrosyl hemoglobin). As recipients, Lewis rats were rendered hyperglycemic by intravenous injection of streptozotocin before transplantation. F344 rats were used as donors of pancreas allografts. Lewis rats were also used as donors of syngeneic pancreas grafts. After transplantation, the blood glucose level returned to a normal level and rejection was defined as the recurrence of hyperglycemia. The mean survival time of pancreas allografts was 14 +/- 0.7 days. The plasma level of nitrite plus nitrate in allografted rats peaked on postoperative day 7. Electron spin resonance spectra of NO bound to hemoglobin were detected in the blood from allografted rats with a peak on postoperative day 7, whereas NO bound to hemoglobin was not detected in the blood from recipients of syngeneic grafts at any sampling time. The results show that NO was synthesized in the earlier period than the elevation of the blood glucose level during rejection after pancreas transplantation in rats.