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Type 2 diabetes is a typical lifestyle disease. We aimed to identify the factors affecting glycemic control in 64 outpatients with type 2 diabetes over a 2-year period. We defined poor glycemic control using a change in glycosylated hemoglobin (ΔHbA1c) of ≥ 0.5% over 2 years and/or HbA1c ≥ 7.5% at the end of the study period. We used a questionnaire to collect information on oral health behavior and lifestyle, including eating and smoking habits, and analyzed the relationships between indices of diabetes control and responses to the questionnaire. The mean (SD) HbA1c of the participants was 6.87% (0.77%) at a baseline, and 6.93% (0.69%) after 2 years. Twenty-three participants (36.0%) had poor glycemic control. ΔHbA1c and the change in body mass index (ΔBMI) correlated (Spearman’s rank correlation, r = 0.350, p < 0.01). The HbA1c at baseline was associated with eating slowly / chewing well, and ΔBMI was associated with perceived oral symptoms. Binominal logistic regression analysis revealed that poor glycemic control was associated with ΔBMI and a smoking habit (odds ratio : 1.62, 95% confidence interval : 1.08–2.42 ; and 4.01, 1.12–14.36, respectively). These findings imply that weight gain and a smoking habit are associated with poor glycemic control in patients with type 2 diabetes.

Glycated hemoglobin (HbA1c) is an important indicator of glycemic control in patients with diabetes. High-performance liquid chromatography (HPLC) is the most commonly used method for measuring HbA1c levels; as HPLC measures all hemoglobin types, the values can be influenced by hemoglobin variants. Moreover, as HPLC-HbA1c levels are low in some diseases, including hemolytic anemia, it may be difficult to differentiate hemoglobin variants from these diseases based on HPLC-HbA1c levels alone. Similar HbA1c values using both HPLC and immunoassays (IAs) are noted for these diseases, while discrepancies are noted in the case of hemoglobin variants. Herein, we describe our process of differential diagnosis for hereditary spherocytosis, the most common inherited hemolytic anemia, in a 56-year-old man presenting with a low HPLC-HbA1c level compared to the glucose concentration, concomitant with anemia, jaundice, hyperbilirubinemia, cholelithiasis, and splenomegaly. There was a discrepancy between HbA1c levels measured with HPLC and IAs and glycated albumin levels. The possibility of hemoglobin variants was unlikely, based on the chromatography and isoelectric focusing results. The haptoglobin levels and reticulocyte counts were low and high, respectively. The direct and indirect Coomb’s tests were negative. The presence of spherocytes on blood smears and flow cytometric analysis of the eosin-5-maleimide binding test supported a diagnosis of hereditary spherocytosis. We recommend that when a discrepancy between HPLC-HbA1c levels and glucose concentrations is noted, clinicians should consider hemolysis or hemoglobin variants as the diagnosis. It should be considered that a discrepancy between HbA1c levels measured with HPLC and IAs does not specifically exclude hemolysis.

The aim of the present study was to examine whether an elderly subject without diabetes experiences hypoglycemia during his daily life or after an oral glucose tolerance test (OGTT), and investigate whether hypoglycemic episodes affect cognitive function. The 85-year-old healthy subject, who is a sports enthusiast, showed lower than normal (

Objective : The aim of this study was to evaluate the association between diabetes-related indicators and oral health behavior among patients with type 2 diabetes. Methods : Seventy-four outpatients were included. We administered a questionnaire and divided the patients into two groups according to oral health behavior and eating habits. We then compared diabetes-related clinical records between the groups and performed logistic regression analysis. Results : Participants who brushed their teeth before bedtime every night had lower BMIs than those who did not. Participants who reported eating slowly and chewing well every day had significantly lower HbA1c than their counterparts. Participants who reported gum bleeding had significantly higher LDL-cholesterol than their counterparts. Binominal logistic regression analysis revealed that BMI < 25 was associated with not brushing teeth before bedtime every night, HbA1c < 7.5 with not eating slowly or chewing well every day, and LDL-cholesterol < 120 with gum bleeding (odds ratio : 0.140, 95% confidence interval : 0.036-0.540 ; OR : 0.085, 95% CI : 0.010-0.736, OR : 0.275, 95% CI : 0.077-0.979, respectively). Conclusions : Our findings suggest that toothbrushing before bedtime every night is associated with reduced risk of obesity and that eating slowly and chewing well are advantageous for glycemic control in patients with type 2 diabetes.J. Med. Invest. 68 : 140-147, February, 2021.

IntroductionGiven an increasing use of dipeptidyl peptidase-4 (DPP-4) inhibitors to treat patients with type 2 diabetes mellitus in the real-world setting, we conducted a prospective observational study (Japan-based Clinical Research Network for Diabetes Registry: J-BRAND Registry) to elucidate the safety and efficacy profile of long-term usage of alogliptin.Research design and methodsWe registered 5969 patients from April 2012 through September 2014, who started receiving alogliptin (group A) or other classes of oral hypoglycemic agents (OHAs; group B), and were followed for 3 years at 239 sites nationwide. Safety was the primary outcome. Symptomatic hypoglycemia, pancreatitis, skin disorders of non-extrinsic origin, severe infections, and cancer were collected as major adverse events (AEs). Efficacy assessment was the secondary outcome and included changes in hemoglobin A1c (HbA1c), fasting blood glucose, fasting insulin and urinary albumin.ResultsOf the registered, 5150 (group A: 3395 and group B: 1755) and 5096 (3358 and 1738) were included for safety and efficacy analysis, respectively. Group A patients mostly (>90%) continued to use alogliptin. In group B, biguanides were the primary agents, while DPP-4 inhibitors were added in up to ~36% of patients. The overall incidence of AEs was similar between the two groups (42.7% vs 42.2%). Kaplan-Meier analysis revealed the incidence of cancer was significantly higher in group A than in group B (7.4% vs 4.8%, p=0.040), while no significant incidence difference was observed in the individual cancer. Multivariate Cox regression analysis revealed that the imbalanced patient distribution (more elderly patients in group A than in group B), but not alogliptin usage per se, contributed to cancer development. The incidence of other major AE categories was with no between-group difference. Between-group difference was not detected, either, in the incidence of microvascular and macrovascular complications. HbA1c and fasting glucose decreased significantly at the 0.5-year visit and nearly plateaued thereafter in both groups.ConclusionsAlogliptin as a representative of DPP-4 inhibitors was safe and durably efficacious when used alone or with other OHAs for patients with type 2 diabetes in the real world setting.

Background The association of glycated albumin (GA) with mortality is unclear in chronic hemodialysis patients with diabetes. We investigated the usefulness of GA by comparing it with hemoglobin A1c (HbA1c) in this patient population. Research design and methods This was a multi-center, prospective cohort study of 841 Japanese chronic hemodialysis patients with diabetes. There were 235 women and 606 men included, with a mean age of 64 years. The primary and secondary endpoints were the incidence of all-cause and cause-specific mortality, respectively. The hazard ratios of GA and HbA1c for the endpoints were estimated using the values at baseline and during the study period. Results During the mean follow-up period of 3.1 years, there were 184 deceased cases, in which 30 and 154 resulted from atherosclerotic cardiovascular disease (ASCVD) and non-ASCVD, respectively. The hazard ratio for a 1% increase in GA was 1.033 (95% confidence interval 1.006–1.060, p = 0.017) for all-cause mortality with a statistical significance when GA was treated as a time dependent variable, but not when the baseline levels or the mean levels during the follow-up period were used in the analysis (p = 0.815 and 0.517, respectively). GA was a significant predictor for ASCVD-related mortality in the above 3 models, but was not for non-ASCVD mortality. Higher levels of HbA1c were only associated with ASCVD-related mortality when HbA1c was treated as a time-dependent variable. Conclusions GA may be useful compared to HbA1c for predicting all-cause and ASCVD-related mortality in Japanese patients with diabetes undergoing chronic hemodialysis.

Glycated albumin (GA) is recommended as a better glycemic indicator than HbA1c in patients undergoing hemodialysis, because the red blood cell lifespan is generally faster than that in normal subjects. However, GA can be also affected by protein loss in urine and hemodialysis fluid. Therefore, in this study, we investigated the effect of albumin leakage induced by hemodialysis on GA. Nine patients undergoing hemodialysis with a large or small amount of albumin leakage were observed for 9 months in a crossover manner. As a result, it was shown that albumin leakage could affect GA, but the effect was practically small considering the prescription of diabetic drugs. The correlations between HbA1c and blood glucose levels and between GA and blood glucose levels were similar in our study. In conclusion, GA was a reliable indicator, even with the change of hemodialysis modality. The influence of albumin leakage induced by hemodialysis on GA was negligible practically. We should recognize that the preferable glycemic indicator in patients undergoing hemodialysis depends on the hemoglobin and albumin metabolism of each patient.

The effectiveness of diabetes prevention programs for the general population of Tokushima Prefecture was investigated. The programs were designed by Tokushima Medical Association’s (TMA’s) Steering Committee for Diabetes Prevention. The committee promoted diabetes prevention by disseminating educational messages on diabetes to the general public and medical care providers, and by establishing a referral system among public health centers and medical institutes throughout Tokushima Prefecture during the period from 2004 to 2009. The outcomes of these activities were evaluated by analyzing data from Prefectural Health and Nutrition Surveys conducted in Tokushima in 1997 (n = 998), 2003 (n = 1,008) and 2010 (n = 1,130). The percentage of subjects with glucose intolerance at the time of initiation of the prevention program in Tokushima tended to increase from 1997 to 2003, but had slightly decreased by 2010, although these differences were not statistically significant. Obesity parameters, mean total energy intake and physical activity as evaluated by the daily step count changed favorably in parallel with changes in the prevalence of diabetes during the study period. The diabetes prevention programs initiated by the TMA committee may be useful in ameliorating the situation of diabetes in Tokushima Prefecture.

Background Glycated haemoglobin (HbA1c) concentration is lower relative to glyacemic control in diabetic patients on haemodialysis. However, it is unknown as to whether this is also true for diabetic patients with end-stage renal disease but not on haemodialysis. Methods Correlations between HbA1c or glycated albumin (GA) and estimated glomerular filtration rate (eGFR) (determined by serum creatinine concentration, sex and age) were investigated in 86 diabetic patients with renal dysfunction not on dialysis. The mean values of HbA1c and of red blood cell (RBC) lifespan were compared among four groups of patients: Group 1 ( n = 30, eGFR ≥ 60 mL/min/1.73 m2), Group 2 ( n = 30, eGFR < 60 mL/min/1.73 m2 but ≥30 mL/min/1.73 m2), Group 3 ( n = 13, eGFR < 30 mL/min/1.73 m2 but ≥15 mL/min/1.73 m2) and Group 4 ( n = 13, eGFR < 15 mL/min/1.73 m2 without haemodialysis). RBC lifespan was determined in each subject from the difference between alveolar carbon monoxide (CO) concentration and atmospheric CO concentration. Results HbA1c was significantly correlated with eGFR ( r = 0.37, P = 0.0004), but GA was not. The HbA1c values in Group 3 (6.8 ± 0.6%) and Group 4 (6.3 ± 0.5%) were significantly lower than that in Group 1 (7.4 ± 0.8%), but there was no difference between Group 2 (7.2 ± 0.7%) and Group 1. There was a significant correlation between RBC lifespan and eGFR, and the mean RBC lifespan in Group 3 (96 ± 35 d) and Group 4 (94 ± 30 d) were significantly shorter than that in Group 1 (127 ± 30 d). Conclusions Diabetic patients with stage 4 or 5 chronic kidney disease not on haemodialysis had significantly lower values of HbA1c and shorter RBC lifespan compared with diabetic patients without renal dysfunction.

OBJECTIVE The aim of this study was to compare the utility of hemoglobin A1c (HbA1c) and glycated albumin (GA) for evaluating the efficacy of the dipeptidyl peptidase-4 (DPP-4) inhibitor, sitagliptin, in patients with type 2 diabetes. METHODS Sitagliptin (50 mg) was administered orally once daily in 67 outpatients with type 2 diabetes. Drug effectiveness was deemed present if the HbA1c or GA level decreased by 5% at week 4 and week 12 relative to the baseline value. RESULTS The mean HbA1c level decreased from 8.1 ± 1.0% at baseline to 7.8 ± 0.9% at week 4 and 7.2 ± 0.8% at week 12. The mean GA level decreased from 25.0 ± 4.5% at baseline to 22.2 ± 3.8% at week 4 and 20.8 ± 3.5% at week 12. At week 4 and week 12, the drug was effective in 37.8% and 71.6% of the patients, respectively, when assessed based on changes in HbA1c, and in 83.6% and 97.0% of the patients, respectively, when assessed based on changes in GA. CONCLUSION GA is superior to HbA1c for evaluating the efficacy of sitagliptin treatment in patients with type 2 diabetes.

A failure in the compensate proliferation of pancreaticβ-cells, as the primary pathogenic event, has been reported in OLETF rat, a model of NIDDM. The aim of the present study is to define whether theβ-cell defect is attributed to the fetal stage islet development, if so, whether the defect involves down regulation of PDX-1 protein expression. Morphological changes,β-cell function, and the expression of PDX-1 protein were examined in the cultured fetal islet-like cell clusters (ICCs) from OLETF rats along with their diabetes-resistant control counterpart LETO rats in the presence of 5.5 or 11.1mM glucose for 48, 72, 96, and 120-hr, respectively. We have observed four abnormalities in the ICCs of OLETF rats. First, a defective morphogenesis was noted during the 72 to 120-hr ICC culture, a period characterized by a dramatic increase in bothβ-cell and non-β-cell (α,σ, and PP) populations in control rats. This defective morphogenesis was demonstrated by a growth retardation of epithelial stratification and poor development of bothβ-cell and non-β-cell masses along with a parallel decline in relevant islet hormone contents. Second, a functional defect was characterized by failure to response to glucose during the 96 to 120- hr-cultured ICCs. Third, the ultrastructural analysis revealed a significant reduction in the number of secretory granules. Four, Western blot analysis showed a significant decrease of PDX-1 protein expression in the OLETF ICCs cultured in 11.1mM glucose for 48 to 72-hr and in 5.5mM glucose for 120-hr. Therefore, we concluded that during the fetal stage of islet development, OLETF rats exhibit both morphological and functional defects.

The Otsuka-Long-Evans-Tokushima fatty (OLETF) rat is a genetic model of spontaneous development of non-insulin-dependent diabetes mellitus (NIDDM) established as an inbred strain after 20 generations of selective breeding. Although they are thought to be genetically homogeneous, they show a dimorphism regarding the diabetic phenotype at an advanced age, with one remaining obese and modestly diabetic while the other becomes lean and overtly diabetic. To clarify the causes for this divergence, we examined the physical, biochemical, and histopathological features in rats at 50 weeks of age, including an analysis of islet angioarchitecture. Sixty-one of 85 male OLETF rats lost weight, while the remainder remained obese. Mean nonfasting plasma glucose in the lean group was 21.8+/-4.6 mmol/L, significantly higher versus the obese group (10.5+/-1.4 mmol/L) and the age-matched control Long-Evans-Tokushima-Otsuka (LETO) group (7.1+/-0.6 mmol/L). Morphological studies of the pancreas from the lean group showed enlarged multilobulated fibrotic islets with a paucity of B cells, whereas islets from the obese group appeared slightly enlarged and showed a relative abundance of B cells. The fine capillaries that form a network in the islets were extremely sparse in the lean group, resulting in a defective glomerular-like configuration, whereas those from the obese group were dense, forming a nearly typical glomerular-like configuration. Increased plasma insulin responses to oral and intravenous (i.v.) glucose and i.v. glucagon loads were nearly absent in the lean group, while they were evident in the obese group, although to a lesser extent compared with the LETO group. Mean insulin secretory output from the perfused pancreas in response to 11.1 mmol/L glucose in the lean group (3.5+/-2.2 pmol/20 min) was significantly lower versus the obese group (8.8+/-6.5 pmol/20 min) and LETO group (22.0+/-10.8 pmol/20 min). Similarly, pancreatic insulin content was significantly lower in the lean group (9.3+/-6.1 microg) versus the others (26.1+/-17.3 microg for obese and 41.1+/-24.8 microg for LETO). In vivo insulin-stimulated glucose uptake measured by a euglycemic clamp technique was significantly higher in the lean group compared with the obese group. These results demonstrate that the dimorphism regarding the diabetic phenotype in male OLETF rats at 50 weeks of age was due to differences in the number of islet B cells, which could be the result of a variation in the capacity for B-cell proliferation among male OLETF rats.

Otsuka Long–Evans Tokushima Fatty (OLETF) rats are a new strain of spontaneous non-insulin-dependent diabetes mellitus (NIDDM) models. To evaluate the role of glucose transporters (GLUT) in the development of diabetes in this model, we examined the action of insulin on the translocation of GLUT4 and GLUT1 in isolated adipocytes, and the GLUT4 protein levels in muscles. Long–Evans Tokushima Otsuka (LETO) rats were used as a control strain. In adipocytes, the GLUT4 protein levels in OLETF rats at 30 weeks of age (diabetic stage) were considerably lower than those in LETO rats at the same age. At a pre-diabetic stage (7 weeks), there were no significant differences in GLUT4 protein levels in adipocytes between LETO and OLETF rats. However, the degree of GLUT4 translocation in OLETF rats was lower than that in LETO rats at 7 weeks of age. There were no differences in GLUT1 levels in adipocytes between the two strains. In muscles, the decrease in GLUT4 protein was observed in OLETF rats at 30 weeks of age. Whether such a difference is under the influence of hyperglycemia was also examined using rats rendered diabetic by 70% pancreatectomy. OLETF rats aged 7 weeks were subjected to partial pancreatectomy (Px) and sham pancreatectomy (sham). At 4 weeks after surgery, GLUT4 protein levels in adipose tissues and skeletal muscles were determined. GLUT4 decrease was observed for both tissues of hyperglycemic Px rats compared with euglycemic sham. Moreover, we examined the direct effect of glucose on GLUT4 protein using primary cultured adipocytes of OLETF rats at 5 weeks of age. After 7-day culture with normal (5.6 mmol/l) or high (25 mmol/l) concentrations of glucose, the GLUT4 protein levels in adipocytes decreased at 25 mmol/l glucose compared with 5.6 mmol/l glucose. These findings suggest an early defect in the insulin resistance of OLETF rats probably reflects impaired GLUT4 translocation. The GLUT4 decrease, which occurs later in the process appears to be a consequence, rather than a cause of diabetes in OLETF rats.

The effects of exercise on alterations in the amount of B-cell mass, insulin content and fibrous tissue present in the pancreas were examined for a diabetic state induced by a 70% pancreatectomy and a prediabetic state in Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model for the spontaneous development of non-insulin-dependent diabetes mellitus (NIDDM). The rats (5-weeks old) were trained either by a 6-week running program or sedentary controls, and at 6-weeks of age, received either a 70% pancreatectomy or a sham-pancreatectomy (sham). As in our previous report, persistent hyperglycemia was detected after surgery for both trained pancreatectomized (Px) and sedentary Px groups. In the nondiabetic sham rats, exercise training resulted in a significantly smaller increase in body weight and beneficial effects on the pancreas as reflected by an increase in pancreatic volume, accompanied by increases in B-cell mass and insulin content as well as less connective tissue in the pancreas compared with the sedentary nondiabetic sham rats. The effect was not sufficient to improve sustained hyperglycemia in the trained diabetic Px rats. This is probably due to a decreased capacity for B-cell proliferation in response to an increased demand for insulin. Although exercise failed to improve this inherent defect in B-cell proliferation, it ameliorated the further deterioration of the pancreas which occurred with hyperglycemia, and resulted in a higher quantity of insulin stored per milligram of B-cell mass (as function of B-cell mass) and less fibrosis in the pancreas, compared with the sedentary diabetic Px rats. The findings of the present study suggest that exercise training has a beneficial effect on the pancreas in the nondiabetic state, and also exerts some positive effects in the diabetic state in this model rat.

Glucokinase (GK) plays a key role in the regulation of glucose-induced insulin secretion, and questions have been raised about its relationship to the glucose transporter GLUT2 and its function in diabetes. This study examined the location of immunostained GK and GLUT2 in beta-cells using confocal microscopy. On double stained sections from pancreases of normal fed rats, GLUT2 Texas Red staining was restricted to the plasma membrane, and GK fluorescein isothiocyanate staining was found in a limited area of cytoplasm that was perinuclear with slight extension toward the apical pole. The GK staining occupied 8.6 +/- 1.7% of total cytoplasmic area and was almost never adjacent to the GLUT2 staining of the plasma membrane. To determine whether the GK staining pattern is altered by metabolic perturbation, normal rats were made acutely hyperglycemic with iv glucose injections; after 20 min the GK staining changed from being localized to become diffusely distributed throughout the cytoplasm. To examine the influence of chronic hyperglycemia, rats were subjected to 90% partial pancreatectomy (Px), which produced glucose levels of 10.9-20.8 mM. When studied 6 or 14 days after Px, those rats with glucose levels greater than 17.7 mM had an altered GK staining pattern that was variable; in some beta-cells GK staining was diffuse and in others the localized staining pattern was preserved. GLUT2 staining was reduced overall, but variability between cells was observed, unlike the more uniform reductions seen with hyperglycemia of longer duration. Other rats received islet transplants to prevent hyperglycemia after Px; their GK and GLUT2 staining patterns were normal. These findings indicate that GK is translocated in association with acute and chronic hyperglycemia. The translocation of this key enzyme for glucose recognition by beta-cells may lead to altered rates of insulin secretion during acute perturbations of fuel provision and in the diabetic state.

Either 200 or 400 syngeneic islets were transplanted under the kidney capsule of normal or streptozocin-induced diabetic B6/AF1 mice. The diabetic mice with 400 islets became normoglycemic, but those with 200 islets, an insufficient number, were still diabetic after the transplantation (Tx). Two weeks after Tx, GLUT2 expression in the islet grafts was evaluated by immunofluorescence and Western blots, and graft function was examined by perfusion of the graft-bearing kidney. Immunofluorescence for GLUT2 was dramatically reduced in the β-cells of grafts with 200 islets exposed to hyperglycemia. However, it was plentiful in grafts with 400 islets in a normoglycemic environment. Densitometric analysis of Western blots on graft homogenates demonstrated that GLUT2 protein levels in the islets, when exposed to chronic hyperglycemia for 2 weeks, were decreased to 16% of those of normal recipients. Moreover, these grafts had defective glucose-induced insulin secretion, while the effects of arginine were preserved. We conclude that GLUT2 expression in normal β-cells is promptly down-regulated during exposure to hyperglycemia and may contribute to the loss of glucose-induced secretion of diabetes.

We studied the effect of treatment with cyclophosphamide (CY) on the incidence of diabetes in Long-Evans Tokushima Lean (LETL) rats, a newly established strain of spontaneously type I diabetic rats. The overall incidence of diabetes among 356 LETL rats treated with CY was 25.6%, which was significantly higher than the 10.5% among 857 untreated LETL rats at 27 weeks of age, and there was no significant sex difference. The incidence of CY-induced diabetes in adult (>16 weeks of age) female LETL rats was 7.7% ( 10 130 ), which was significantly lower than that in other CY-treated groups of LETL rats. No diabetes mellitus was induced by administration of CY to 23 diabetes-resistant LETO rats. There were no significant differences in the degrees of hyperglycemia or hyperketonemia in spontaneously and CY-induced diabetic LETL rats, but the plasma glycated albumin level of CY-induced diabetic rats (10.3% ± 2.1%) was significantly higher than that of spontaneously diabetic rats (8.2% ± 1.3%), suggesting that plasma glucose levels increased more rapidly in the latter. More than half of the diabetic rats showed type C or D morphological changes of the islets, ie, atrophic change with little mononuclear cell infiltration or almost complete loss of the islets. However, distributions of various types of morphological changes in the islets were not significantly different in the two groups. Ovariectomy (OVX) significantly increased the incidence of CY-induced diabetes in adult female rats from 7.7% to 20.8%. The number of CD8 + cells was significantly increased in noncastrated adult female LETL rats and decreased to the level of other groups after OVX. These results indicate that CY is diabetogenic in our colony, and that its effect is related to the gonadal hormone environment.

We studied the natural course of disease in spontaneously diabetic rats, Long Evans Tokushima Lean (LETL) rats, to determine whether it showed similar pathogenetic heterogeneity to that of patients with insulin-dependent diabetes mellitus (IDDM) with regard to the relationships between age at onset, rapidity of disease progress, and degree of β-cell function at the time of its manifestation. Type 1 diabetes developed in 35 rats (6.3%) between 40 and 140 days of age. Eight rats that became diabetic at age 69 days or less were more severely ketotic at the time of first detection of glycosuria and showed more rapid deterioration than seven rats that became diabetic later after birth (mean plasma 3-hydroxybutyrate levels, 4,707 ± 1,215 pmol/L v 1,390 ± 859 pmol/L; mean ± SEM, P < .01). The mean plasma levels and pancreatic content of immunoreactive insulin (IRI) of the early onset rats, 47 ± 13 pmol/L and 19 ± 12 pmol/g tissue weight, were significantly lowere (P < .01) than the corresponding values of the late-onset rats, 262 ± 52 pmol/L and 348 ± 87 pmol/g tissue weight, respectively. Both values were markedly lower than the mean values of 25 nondiabetic LETL rats, 976 ± 122 pmol/L and 3,488 ± 628 pmol/g tissue weight. Plasma immunoreactive glucagon (IRG) levels were significantly increased in the diabetic groups (early onset, 57 ± 13 pmol/L; late-onset, 51 ± 12 pmol/L; nondiabetic, 18 ± 1 pmol/L; P < .01). These changes in pancreatic hormone levels of the early onset and late-onset rats were compatible with the histological features of their pancreatic islets. The titers of plasma competitive insulin autoantibodies (CIAA) were within the normal range in all but two diabetic LETL rats. The changes in blood chemistry, pancreatic hormone content, and histology of the pancreatic islets of 13 cyclophosphamide-induced diabetic LETL rats were similar to but less marked than those of the spontaneously diabetic rats with regard to the relationship between age at onset and β-cell function at the time of manifestation of disease. These results demonstrate that LETL rats with spontaneous or cyclophosphamide-induced type 1 diabetes showed similar pathogenetic heterogeneity to that of IDDM patients with respect to the relationship between age at onset and the rapidity of progress of disease; pancreatic β cells tend to be more rapidly and severely damaged in early onset than in late-onset diabetic LETL rats.

The contribution of the preceding blood glucose level to glycated protein was theoretically analyzed using a linear kinetic model and was compared with experiments using streptozotocin-diabetic rats. We assumed that the glycation process can be described by one irreversible step and that the fraction of glycated protein is small. A formula based on these two assumptions showed that the level of glycated protein was proportional to the weighted mean blood glucose concentration in the preceding period and that the weight function was determined by the metabolic characteristics of each protein. For assessing the usefulness of the present formula, the value calculated for the response of glycated albumin (GA) to acute blood glucose change in streptozotocin-diabetic rats was compared with the data obtained under three experimental conditions. The calculated responses of GA showed a little more retardation than the observed data, but showed enough agreement with them.

To determine whether starvation affects the metabolism of glucagon-like peptide-1 (GLP-1), we measured the plasma levels of proglucagon-derived peptides and the biosynthesis and posttranslational processing of proglucagon in groups of six rats starved for 1, 3 and 5 days. The plasma levels of GLP-1 immunoreactivity (GLP-1 IR) and glucagon-like immunoreactivity (GLI) decreased during starvation reaching 79 and 56% of the respective control values by day 5 (P less than 0.05 and less than 0.01 vs control). The same is true of the plasma IRI level. The ileal contents of GLP-1 IR and GLI were 50.8 +/- 3.8 pmol/g wet weight and 161.8 +/- 13.2 pmol/g wet weight, respectively, on day 5 of starvation, which were significantly lower (P less than 0.01) than the respective values of 94.8 +/- 16.6 pmol/g wet weight and 262.7 +/- 28.1 pmol/g wet weight in control rats. However, the pancreatic contents of proglucagon-derived peptides tended to increase during starvation, although their increases were not statistically significant. No significant change in the posttranslational processing of proglucagon was detected during starvation. The decrease in the ileal proglucagon-derived peptides content was not associated with a decrease in intestinal proglucagon mRNA transcripts. These results suggested that decreased synthesis of proglucagon-derived peptides by the intestine was largely responsible for the reductions in their circulating levels in starved rats.

Diabetes mortality rates of Tokushima prefecture have been worst one in Japan for 12 years. We started up the organization named "Tokushima Medical Doctors Association against Diabetes" for the disease prevention and the improvement of the treatments in Tokushima prefecture. More than 240 medical doctors in Tokushima prefecture joined the association. The activities of the association are ( 1) training of medical doctors, (2) education for co-medical staffs, (3) education and enlightenment for patients and the public, (4) cooperation with Tokushima prefectural medical association and the communities. For the purpose of education for the co-medical staffs, we organized the association of Certified Diabetes Educator of Japan in Tokushima and support the association as the secretariat office. We also work as Tokushima branch office of Japan Association for Diabetes and Education and Care. The prevention of disease and the improvement of medical activity level are one of the big roles those the university hospital is responsible, because the university hospital is anticipated to work as a medical leader in the community. As the University hospital can take care of all medical staffs, so it is thought to be important to contribute the local medical treatment level different with the medical association and prefecture secretariat. The promotion conference for Diabetes mellitus was established last year. The relation among the associations we take care, the local medical association, and the prefecture secretariat are getting better. We hope that our cooperative activities will contribute to reducing morbidity and mortality from diabetes in Tokushima prefecture.

A sexual dimorphism regarding the incidence of diabetes mellitus in OLETF rat, a model of Type II diabetes, has been reported. As a result, the effects of ovarian hormones on beta cells per se was examined by comparing the capacity of beta-cell proliferation and changes in blood glucose and plasma insulin concentrations after a 70 % pancreatectomy. All female animals were randomly assigned to two protocols. The rats involved in protocol I received either a 70 % pancreatectomy (Px) or a sham pancreatectomy (sham) at 6 weeks of age, along with their diabetes-resistant counterparts, female LETO rats, which served as normal controls. The rats belonging to protocol II were given an ovariectomy (Ox) at 5 weeks of age, and one week later, they were subjected to either Px or the sham operation, with/without hormone (estradiol, 50 μg/kg; testosterone, 1 mg/kg) replacement. The findings indicate that the capacity for compensatory growth of beta cells after Px was affected by both sex hormonal and genetic components, since a 70 % Px resulted in sustained hyperglycaemia within the first week after surgery, but was ameliorated by an increase in beta-cell mass thereafter in the non-Ox Px OLETF rats. The Ox also caused a decline in beta-cell mass which could be improved by replacement with ovarian hormones. Not only endogenous but also replacement ovarian hormones, led to a beneficial effect on beta cells per se in OLETF female rats. This was reflected by an increased beta-cell mass accompanied by a parallel increase in plasma immunoreactive insulin concentration. The effects of ovarian hormones, however, contributed to the beta-cell hypertrophy rather than expansion of the beta-cell population to achieve glucose homeostasis, as evidenced by an increased area of individual beta-cell after Px rather than an increased BrdU-labelling index for the beta cells. The present study suggests that ovarian hormone-induced beta-cell hypertrophy may typically occur, to compensate for changes in functional demand as the results of a 70 % Px in female OLETF rats. [Diabetologia (1998) 41: 799–805]

Hypertriglyceridemia is known to be a feature of obesity-related NIDDM, but the patho-etiological significance of this association is obscure. The effects of triglycerides (TGs) on β-cell function and morphological changes in pancreas were examined using in vivo and in vitro approaches in male OLETF rats at ages 6, 12, and 30 weeks, with their diabetes-resistant counterpart, LETO rats, as normal controls. The results showed that, in the fasting state, plasma TGs in OLETF rats were increased 2.5-fold at age 6 weeks, 3.3-fold at age 12 weeks, and 6.2-fold at age 30 weeks, compared with age-matched LETO rats. The TG content in islets from 12-week-old OLETF rats was significantly increased when compared with those from their age-matched counterparts, but this was not the case with the 6-week-old OLETF rats. Therefore, the islets from 6-week-old rats were cultured with either free fatty acids (FFAs; 1.0 mmol/1 sodium oleate) or TG (5.0 mmoM Intralipide) for 72 h. Several abnormalities in OLETF rats were evident, in contrast to the results from control LETO rats: 1) glucose-induced insulin secretion was more inhibited by either FFAs or TGs in the presence of 27.7 mmol/l glucose, a result associated, at least in part, with reduced glucokinase activity in the islets; 2) a marked elevation in TG content was found in the islets; and 3) the deposition of fat droplets in the enlarged islets, even in the β-cells, was found by Oil Red O-insulin double staining at age 30 weeks. In conclusion, hypertriglyceridemia resulted in significant TG stores in the islets, which subsequently inhibited glucose-induced insulin secretion, at least in part, via reduced glucokinase activity in the islets. Fat droplets in islets, therefore, may play an important role in hastening the development of NIDDM in this rat model.

To clarify the mechanism(s) of the antidiabetic effects of truncated glucagon-like peptide-1 (GLP-1) in diabetics, we examined its insulinotropic and extrapancreatic effects in a newly established strain of spontaneously non-insulin-dependent diabetic (NIDDM) rats, Otsuka Long-Evans Tokushima Fatty (OLETF) rats, that received a continuous infusion of truncated GLP-1 620 pmol/d/kg (G group, n = 12) or of vehicle (V group, n = 12) for 4 weeks by Alzet pump. Nonfasting plasma glucose levels were significantly lower (P.05) in the G group than in the V group (7.0 +/- 0.67 v 9.1 +/- 1.7 mmol/L), and fasting plasma immunoreactive insulin (IRI) levels were lower in the former than in the latter (0.63 +/- 0.31 v 0.78 +/- 0.25 nmol/L). At day 15 of infusion, the G group showed an attenuated plasma glucose response to an oral glucose load, but had plasma IRI levels comparable to those in the V group. A long-term infusion of truncated GLP-1 increased the glucose infusion rate (GIR) significantly (P.05) during a euglycemic-hyperinsulinemic clamp test (59.0 +/- 14.8 mumol/kg/min for group G v 38.9 +/- 12.2 for group V), but hepatic glucose output (HGO) did not differ significantly for either group. Uptake of 2-deoxy-D-glucose (2DG) by peripheral muscles in the G group was as much as 2.4-fold higher than in the V group (5.52 +/- 2.04 v 2.29 +/- 0.97 mumol/100 g muscle weight/min). We conclude from these data that truncated GLP-1, in addition to its well-known incretin effect, is capable of augmenting insulin action in peripheral tissues of diabetics, which can contribute, in part, to improve glucose intolerance in OLETF rats.

We examined whether a 70% pancreatectomy changes the morphofunctionality of pancreatic A cells in a model rat (Otsuka Long-Evans Tokushima Fatty [OLETF]) with non—insulin-dependent diabetes mellitus. Male OLETF rats aged 6 weeks were assigned to two groups: partial pancreatectomy (Px) and sham pancreatectomy (sham). The Px group was divided into three subgroups based on treatment received after surgery, which included treatment with nicotinamide, phlorhizin, or saline. As a control, their diabetes-resistant counterparts, Long-Evans Tokushima Otsuka (LETO) rats, were similarly treated and grouped. Six weeks after surgery, plasma glucagon responses to arginine- and insulin-induced hypoglycemia were examined. In addition, the glucagon content and morphological features of pancreatic A cells in Px-remnant and remnant-equivalent pancreata were investigated 7 weeks after surgery.A sustained nonfasting hyperglycemia was evident in Px OLETF rats, which was ameliorated by administration of nicotinamide. The glucagon content and A-cell mass were not decreased significantly in the remnant pancreas of saline- and phlorhizin-treated Px animals of either strain but increased in nicotinamide-treated animals compared with those in the remnant equivalent of the respective sham rats. The areas under the response curves of plasma glucagon (ΣIRG) during an arginine infusion test and 90 minutes of insulin-induced hypoglycemia were 1,010.7 ± 72.9, 1,083.1 ± 95.3, 1,029.6 ± 65.0, and 1,779.8 ± 226.9 pmol · L −1 · min −7 versus 1,997.0 ± 283.1, 2,217.0 ± 395.0, 1,479.6 ± 78.0, and 3,466.4 ± 174.0 pmol · L −1 · min −1 in phlorhizin-, nicotinamide-, and saline-treated Px OLETF and sham OLETF rats, respectively. A similar trend was observed for differences in the response of pancreatic A cells to both stimuli among various groups of LETO rats. There was no significant difference in ΣIRGs during both tests between OLETF and LETO rats with similar treatments, except during an insulin tolerance test (ITT) in saline-treated Px rats. The magnitude of the plasma glucagon response to both stimuli in the test animals was roughly parallel to the glucagon cotent in the pancreas. These findings suggest that differences in the proliferation and responsiveness of pancreatic A cells between OLETF and LETO rats after a 70% pancreatectomy are not nearly as significant as compared with B cells.

Exercise training has been shown to be effective in preventing the development of non-insulin-dependent diabetes mellitus (NIDDM) in a model rat (Otsuka-Long-Evans-Tokushima Fatty [OLETF]). For determination of how long a preventive effect of exercise training against the development of NIDDM lasts in this model, six male OLETF rats each were assigned to training (1) for a whole experimental period, from 7 to 28 weeks of age (E-E); (2) for the first half of the period, from 7 to 15 weeks of age (E-S); and (3) for the second half of the period, from 16 to 28 weeks of age (S-E). In addition, eight male OLETF rats were given no exercise during the experimental period (S-S). At 28 weeks of age, E-E, E-S, S-E, and S-S rats, weighed averages of 514, 542, 557, and 669 g and had abdominal fat deposits of 13.9, 21.3, 38.2, and 76.0 g, respectively. At 28 weeks of age, the cumulative incidence of NIDDM in S-S was 100%, while none of the trained rats were diabetic. The glucose infusion rate (GIR) during a hyperinsulinemic euglycemic clamp test, an index of insulin sensitivity, in the E-E group was significantly greater than that in the S-S group. The values in the E-S and S-E groups were slightly, but not significantly, less than that in the E-E group. Morphologic studies on the pancreas of E-E rats and S-E rats showed minimal changes of islets, whereas sections of islets from E-S rats appeared slightly enlarged and fibrotic, although significantly less than those of islets of S-S rats. These results demonstrate that the preventive effect of excercise training against the development of NIDDM lasts for at least 3 months after the cessation of exercise in this model.

We studied whether obesity or inheritance was the more important factor in the development of non-insulin-dependent diabetes mellitus (NIDDM) using female Otsuka-Long-Evans-Tokushima Fatty rats (OLETF) possessing one of the diabetic genes, ODB-1 , and male Long-Evans-Tokushima-Otsuka rats (LETO) possessing no ODB-1 , neither of which were diabetic when bred normally. Diabetes-resistant male LETO rats and female OLETF rats (4 weeks old) were assigned to three groups of 6 rats each, respectively; two groups in which obesity was induced by high calorie ‘cafeteria’ diet (D), or ventromedial hypothalamus lesions (V) with normal chow diet and a control group fed on normal chow (C). Six male OLETF rats were used as NIDDM positive controls. The mean daily energy intakes of obese male LETO and female OLETF rats were higher than those of the respective C groups. At 27 weeks of age, the average body weights of the obese LETO and female OLETF rats were significantly higher than those of the respective C groups and similar to that of the male OLETF group. Abdominal fat deposits of the obese groups were significantly higher than those of the respective C groups. At 28 weeks of age, the cumulative incidence of diabetes mellitus in obese LETO rats was 0% in group D and 17% in group V, while that of obese female OLETF rats in groups D and V were 100%. At 29 weeks of age, the plasma immunoreactive insulin (IRI) responses to glucose in obese female OLETF rats, groups D and V, were higher than that in group C. In obese LETO rats, insulin-stimulated glucose disposal in vivo was similar to that in group C, but in obese female OLETF rats, it was reduced to 41% in group D and 37% in group V of that in group C. Sections of islets of the pancreas of obese LETO rats appeared histologically normal, whereas those of obese female OLETF rats showed enlarged multilobulated fibrotic islets. These results demonstrate that obesity is necessary, but not sufficient alone for the development of NIDDM in these rat models.

Long-term glyburide therapy has been reported to improve glucose-induced insulin secretion in patients with NIDDM. We examined the effects of glyburide on the synthesis release of insulin and insulin gene expression in isolated islets in vitro. Incubation with glyburide (500 ng/ml) significantly increased insulin release without affecting the insulin content. The PPI mRNA level was not increased after incubation for 1 h but was increased after incubation for 20 h. Incubation with 5 ng/ml of glyburide for 1 h or 20 h had no effect on the content or release of insulin, but incubation with 5 ng/ml of glyburide for 20 h significantly increased the PPI mRNA level and enhanced insulin release induced by 11 mM glucose. These results suggest that a high concentration of glyburide stimulates insulin release directly, while a low concentration of glyburide increases the PPI mRNA level and may thereby enhance glucose-induced insulin release.

DNA sequence analysis of class II HLA from Caucasian and black patients with type 1 (insulin-dependent) diabetes mellitus has suggested that aspartic acid at position 57 (Asp 57) of the DQ beta chain provides protection against insulin-dependent diabetes mellitus (IDDM). In contrast, most Japanese patients with IDDM have Asp 57-positive alleles. To determine the reason for the differences and to localize the HLA-linked diabetogenic gene in Japanese, we studied the DQA1 and DQB1 genes of Japanese patients with IDDM and control subjects by the polymerase chain reaction in combination with restriction fragment length polymorphism analysis. Associations of DQA1*0301 and DQB1*0303 with IDDM were observed. DQA1*01 was associated negatively with IDDM. The HLA-DR9 haplotype, which is associated positively with IDDM in Japanese, was associated with DQA1*0301 and DQB1*0303, indicating that the Japanese DR9 haplotype is the same as that in caucasians but different from that in blacks. Of the loci on Japanese DR9 haplotypes, the DQA1*0301 allele showed the highest association with IDDM. DQB1*0303 was also positively associated with IDDM. Since DQB1*0303 is identical to DQB1*0302 except that it contains Asp 57, the data suggests that an Asp 57-positive allele confers susceptibility to IDDM when the whole molecule of the DQ beta chain is similar to other susceptible DQ beta chains. DQA1*0301 appears to be a marker of IDDM in all these populations: Japanese, caucasian, and black.

In order to investigate whether urinary C-peptide (UCP) excretion can be a useful index of insulin-dependent diabetes mellitus (IDDM) with unstable glycemic control, UCP was measured in nine IDDM patients with unstable glycemic control, nine IDDM patients with stable glycemic control, and 12 non-insulin-dependent diabetic (NIDDM) patients treated with insulin. The UCPs in overnight urine (U1) and fasting single void urine (U2) in IDDM patients with unstable glycemic control were significantly lower than those in IDDM patients with stable glycemic control (U1: 0.03 +/- 0.03 vs 0.24 +/- 0.20 nmol/mmol-Creatinine, U2: 0.02 +/- 0.01 vs 0.20 +/- 0.20 nmol/mmol-Cr, mean +/- SD, both P less than 0.01). The UCPs in U1 and U2 in both groups of IDDM were significantly lower than those in NIDDM (U1: 0.97 +/- 0.52, U2: 0.73 +/- 0.41 nmol/mmol-Cr, both P less than 0.01). The UCPs in U1 and U2 significantly correlated with incremental C-peptide response to intravenous glucagon injection and with glycemic stability assessed by the standard deviation of 10 previous fasting plasma glucose levels. These results suggest that UCP reflects their residual insulin secretory capacity and that UCP can be a useful index which distinguishes patients with unstable IDDM from those with stable diabetes mellitus.

To investigate how urinary excretion rates (UERs) of maltose and glucose are determined after intravenous maltose infusion, maltose and glucose solutions were infused at various rates and the relationships between UERs of maltose and glucose and their plasma concentrations were examined. Results showed the existence of a threshold plasma maltose concentration for the urinary excretions of maltose and glucose and the existence of a maximum rate of urinary glucose excretion after maltose infusion. Elevation of plasma glucose concentration by simultaneous glucose infusion increased urinary glucose excretion but did not increase urinary maltose excretion; the relationship between plasma total sugar concentration and urinary total sugar excretion was unchanged. Results suggest that maltose administered intravenously is hydrolyzed to glucose by maltase in renal tubules and reabsorbed as glucose competitively with glucose derived from plasma and that the maximum utilization of intravenously infused maltose is determined by the tubular glucose reabsorption capacity.

The cellular mechanism of glucagon gene expression in intact rat islets and their synthesis and release of glucagon were investigated. Arginine significantly increased the amounts of preproglucagon mRNA and glucagon in the islets and glucagon release. H-7, a specific inhibitor of protein kinase C (PKC), significantly inhibited these effects of arginine. However, H-8, a potent inhibitor of cyclic nucleotide-dependent protein kinases, did not affect the arginine-induced biosynthesis of glucagon or glucagon release. These results suggest that the regulation of glucagon gene expression by arginine is mediated by PKC, not by cyclic nucleotide-dependent protein kinases.

Insulin-dependent diabetes mellitus (IDDM) in Caucasians is closely associated with the HLA-DQ gene, especially the residue 57 of the DQ beta chain. Aspartic acid at this position provides protection against IDDM, and substitution of this residue by alanine, valine or serine increases susceptibility to IDDM. To determine whether this is a common feature of IDDM in different ethnic groups, we studied DQB1 DNA in Japanese patients with IDDM by polymerase chain reaction and non-radioactive restriction site analysis. In contrast to Caucasian patients with IDDM, most Japanese patients with IDDM possessed at least one aspartic acid at position 57 of DQ beta. This finding strongly suggests that aspartic acid at position 57 of DQ beta does not protect the Japanese from IDDM.

Glucagon-like peptide-1 (GLP-1) has been reported to inhibit glucagon release. To investigate the mechanism involved, we examined the effects of GLP-1 on the preproglucagon mRNA level and the content and release of glucagon in the isolated rat islets. Arginine significantly increased the content and release of glucagon after incubation for 1 h or 18 h. The preproglucagon mRNA level was not increased after incubation for 1 h but was increased after incubation for 18 h. GLP-1(7–36 amide) significantly decreased the content and release of glucagon after incubation for 1 h or 18 h, but did not affect arginine-induced increase in the preproglucagon mRNA level after incubation for 18 h. These data suggest that GLP-1 suppresses post-transcriptional processes in the content and release of glucagon.

We have cloned cDNAs for IgG, induction factor and T cell replacing factor. The recombinant factors were shown to have multiple activities on B cells, which could explain most, if not all, of B cell growth and differentiation factor activities so far claimed. Since the recombinant factors were also shown to affect bone marrow-derived cells other than B cells, the names of interleukins 4 and 5 were proposed for IgG1 induction factor and T cell replacing factor, respectively.

Complementary DNA encoding the IgG1 induction factor, the first lymphokine directed to B lymphocytes, from a murine T-cell line has been cloned using a new strategy. The putative primary amino-acid sequence was deduced from the nucleotide sequence determined. The lymphokine synthesized by the direction of this cloned cDNA has many other functions, such as production of B-cell growth factor-1 and induction of Ia on B cells.

著明な低栄養状態にて血中CEAが異常高値を示し,栄養状態の改善とともにCEAが低下した症例を3例経験した. 3症例とも悪性腫瘍の術後で消化吸収不良症候群から極度の低栄養状態に陥ったが,臨床的には悪性腫瘍の再発は否定された.低栄養状態にてCEA高値が認められたが,栄養改善とともにCEAは低下,低栄養による代謝低下がCEA上昇に関連している可能性が示唆された.

We have determined the complete organization of the mouse CH gene family, which is comprised of the 8 CH genes in the order 5’-JH-6.5kb-Cμ-4.5kb-Cδ-55kb-Cγ3-34kb-Cγ1-21kb-Cγ2b-15kb-Cγ2a-14kb-Ce-12kb-Cα-3’. The S regions, which contain characteristic tandemly repeated unit sequences, are located 5’ to each CH gene except for the Cδ gene. There are at least two types of repetitive sequences dispersed in this 200 kb region. No pseudogenes are present. The arrangements of the CH genes in BALB/c and C57BL mice are similar, but the lengths of the S regions vary. The basic structures of all the CH genes are similar in that coding sequences are interrupted at the junctions of the domains and the hinge regions. Comparison of the nucleotide sequences of the CH genes revealed that sequence segments have been exchanged among members of the CH gene family. Cloning and characterization of human Cγ genes, i.e. Cγ1, Cγ2, Cγ3, Cγ4 and φCγ, indicate that the human Cγ gene family evolved by dynamic DNA rearrangements, including gene duplication, exon duplication, and exon reassortment by unequal crossing-over. A human pseudo-epsilon gene (Ce3) is a processed gene that has completely spliced out introns. The presence of movable genetic elements surrounding the Ce3 gene suggests that the Ce gene evolved by a translocation mechanism. Although S-S recombination has been shown to take place in myelomas and hybridomas secreting a large amount of immunoglobulin, analyses of the CH gene organization in normal spleen B cells bearing immunoglobulin on their surface suggest that RNA splicing may be responsible for the first step in class switching, followed by S-S recombination. The nucleotide sequences of S regions contain short common sequences, TGGG(G) and (G)AGCT. Comparison of nucleotide sequences surrounding recombination sites revealed common sequences TGAG and TGGG. A sister chromatid exchange model was proposed to explain deletion of CH genes accompanying S-S recombination. We have found that the S region serves as a preferred recombination site in E.coli extracts.

Flow cytometric analyses of surface immunoglobulins of human neoplastic B cells from four patients indicated that more than two isotypes were expressed on the surface of each patient's neoplastic B cells. Southern blot analysis of DNAs of these cells showed that each patient's neoplastic cells had the monoclonal rearrangement profile of the J segment of the immunoglobulin heavy-chain gene. Heavy-chain constant-region genes of these cells had no deletion associated with S-S recombination. Northern blot analysis of RNA from two neoplastic cells revealed that each RNA contained comparable amounts of mRNAs for two different isotypes which were identified by surface staining. These results support the hypothesis that the simultaneous expression of two different isotypes in a certain stage of B-cell differentiation is mediated by alternative RNA splicing without DNA deletion.

The involvement of soluble factors in the regulation of mammalian cell proliferation and differentiation has received considerable attention within the past decade. Extensive investigations have established the importance of soluble factor mediated control, during the ontogeny of many cellular populations, including normal epithelial, fibroblastic, hematopoetic and lymphoid (1).

To understand molecular mechanisms of clonal expansion of lymphocytes we have isolated cDNA clones for two lymphokines, interleukins (IL) 4 and 5 that induce proliferation and maturation of B-lymphocytes. Structures of IL-4 and IL-5 revealed a remote homology with other lymphokines such as IL-3 and γ-interferon. IL-4 and IL-5 were shown to affect not only B-lymphocates but also T-lymphocytes and several other cells derived from bone marrow stem cells. We have also studied the structure and function of the IL-2 receptor: our focus was the molecular basis for the high and low affinity states of the receptor encoded by the identical cDNA. We propose the affinity conversion model that the high-affinity state of the IL-2 receptor is a ternary complex of IL-2, the IL-2 receptor, and a postulated “converter protein”, which is fewer in number than the receptors.