Associations of segment-specific pulse wave velocity with vascular calcification: the Atherosclerosis Risk in Communities (ARIC) Study

Background

Pulse wave velocity (PWV) is a non-invasive measure of arterial stiffness and a predictor of cardiovascular disease (CVD). Vascular calcification, especially coronary artery calcium (CAC) measured by computed tomography (CT), is one of the strongest predictors of CVD but requires radiation for measurement. PWV may be helpful to identify persons with vascular calcification who may benefit from formal assessment of vascular calcification with CT. However, the associations between PWV and vascular calcification across different vascular beds have not been fully investigated.

Purpose

The aims of this study were to quantify the association between PWV and calcification at different segments and to explore whether PWV can identify individuals with vascular calcification beyond traditional risk factors.

Methods

Among 1486 ARIC Study participants (mean age 79.3 [SD 4.2] years), we measured PWV by OMRON VP1000plus at the following segments: heart-carotid (hcPWV), heart-femoral (hfPWV), carotid-femoral (cfPWV), heart-ankle (haPWV), brachial-ankle (baPWV) and femoral-ankle (faPWV). Participants were stratified into four groups based on quartiles of each PWV measure. Dependent (i.e., outcome) variables were high calcium score (≥75th percentile of Agatston score by CT) of the following vascular beds (including valves): coronary arteries, aortic valve ring, aortic valve, mitral valve, ascending aorta, and descending aorta. We ran multivariable logistic regression models and assessed c-statistics as a measure of prediction discrimination.

Results

Only cfPWV was significantly positively associated with high CAC (adjusted odds ratio [OR] for the highest vs. lowest quartile: 1.73 [95% CI: 1.17–2.55]) (green dot in figure). The associations were overall most evident for descending aorta calcification, with significantly positive results for hfPWV (gold dot in figure), cfPWV (green dot), haPWV (emerald dot), and baPWV (blue dot). For example, adjusted OR for the highest vs. lowest quartile of cfPWV was 4.08 (2.70–6.24). hfPWV and cfPWV were significantly associated with mitral valve calcification as well. In contrast, faPWV (purple dots) was inversely associated with calcification of aortic valve ring, ascending aorta, and descending aorta. For descending aorta calcification, even the second highest quartile of the following measures demonstrated significant adjusted OR: hfPWV (3.21 [2.11–4.95]), cfPWV (2.11 [1.40–3.20]), and baPWV (1.75 [1.14–2.69]). Simultaneously adding cfPWV and hfPWV improved c-statistic for CAC (Δc-statistic 0.011 [0.0007–0.022]) and descending aorta calcification (0.035 [0.017–0.053]).

Conclusions

The associations of PWV with vascular calcification varied substantially across segments, with descending aorta calcification most closely linked to PWV measures and cfPWV most robustly associated with calcification of multiple vascular beds. cfPWV and hfPWV, together, improved discrimination of high CAC beyond traditional risk factors.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The National Heart, Lung, and Blood Institute, National Institutes of Health

Association between adherence to home-based walking exercise with a pedometer and one-year adverse outcomes among lower extremity peripheral artery disease patients with endovascular treatment

Background

Home-based exercise after endovascular treatment (EVT) for lower extremity peripheral artery disease (LE-PAD) patients with intermittent claudication is suggested as an alternative therapy for supervised exercise; however, an association of adherence to home-based exercise with clinical adverse events has not been fully investigated.

Purpose

We aimed to investigate the association of adherence to home-based exercise with 1-year major adverse events (MAE), patency, and leg symptoms after EVT in a contemporary Japanese registry.

Methods

A total of 500 patients with LE-PAD within the Long Term Outcome of Endovascular Therapy for PAD with Intermittent Claudication Observational Prospective Multicenter (ASHIMORI-IC) registry (UMINCTR, UMINehab724.203718753) who underwent EVT between January 2016 and March 2019 were included in the analysis. After EVT, all patients were instructed to do home-based walking exercise with a pedometer. The study population was divided and compared between 2 groups according to adherence to home-based exercise: well-adherence and poor-adherence. The adherence of home-based exercise was as defined by step count derived from a pedometer on sites. The primary outcome was MAE defined as composite of all-cause death, myocardial infarction, stroke, target vessel revascularization, and major amputation of target lower limb for one year. The main secondary outcome was 1-year primary patency of the treated lesion, and the improvement of leg symptom (6-minute walk distance [6MWD] and claudication distance). The study followed the Consensus definitions from peripheral academic research consortium criteria.

Results

Overall, the mean age was 72.8 years, and 78% were men. At 1 year, MAE occurred in 45 patients (9.0%), and the primary patency rate was 85.3% (94.2% of EVT for aortoiliac and 71.9% of EVT for femoropopliteal). A significant difference in the incidence of MAE was observed between the well-adherence group and the poor-adherence group (10 of 233 patients [4.3%] vs. 35 of 267 patients [13.1%]; P<0.001). After multivariate Cox regression analysis, patients in the well-adherence group showed the lower hazard ratio for 1-year MAE (0.30; 95% confidence interval, 0.15–0.58; P<0.001) compared to those in the poor-adherence group. In the well-adherence group, compared with the poor-adherence group, higher primary patency rate (88.9% vs 81.5%; p=0.015), longer claudication onset distance (370 m [IQR 240–453 m] vs 240m [IQR 126–324 m]; P<0.001), and longer 6MWD (422 m [IQR 359–483 m] vs 325 m [IQR 213–400 m]; P<0.001) were observed even after adjusting for each baseline value.

Conclusion

Our study demonstrates the importance of adherence to home-based walking exercise after EVT in LE-PAD patients.

Funding Acknowledgement

Type of funding sources: None.

Detection of hepatocyte growth factor in oral rinses using water for possible periodontal diagnosis

The aim of this study is to analyze the relationship between Hepatocyte Growth Factor (HGF) levels in oral rinses using water and clinical parameters of periodontitis; and furthermore, to evaluate the potential of a prototype HGF immunochromatographic paper test strip (HGF-TS) for screening of periodontitis, in comparison with a commercially-available occult blood (hemoglobin) test strip (Hb-TS). Clinical periodontal parameters were recorded, and oral rinses were collected, from 125 subjects. Then, the presence of HGF, and hemoglobin (Hb), in each sample was detected using a prototype HGF-TS and an Hb-TS. In addition, the concentrations of HGF and Hb were also determined in each sample is necessary HGF concentrations in oral rinses showed significant correlations with clinical parameters of periodontitis. The positive rate and read value on HGF-TS showed significantly high values in cases of severe periodontitis compared to healthy subjects. Hb-TS showed generally higher positive rates than HGF-TS; however, it showed false positive results in healthy subjects. The concentration of HGF in oral rinses showed close association with the severity of periodontitis, suggesting that the prototype HGF-TS has potential for use in the diagnosis of periodontitis, although further refinement of the test strip is required to increase the sensitivity.

1407Drug effect of luseogliflozin and voglibose on heart failure with preserved ejection fraction in diabetic patients: a multicenter randomized-controlled trial

Background

Recent randomized, placebo-controlled trial in patients with type 2 diabetes demonstrated that the sodium-glucose cotransporter 2 inhibitors reduced mortality, cardiovascular events and hospitalization for heart failure. However, those trials were not specialized design to investigate the effect of sodium-glucose cotransporter 2 inhibitors in patients with heart failure, in particular with heart failure with preserved ejection fraction.

Purpose

The aim of this study was to evaluate the drug efficacy of luseogliflozin, a sodium-glucose cotransporter 2 inhibitor, compared with voglibose, an alpha-glucosidase inhibitor, using brain natriuretic peptide (BNP) in type 2 diabetes patients with heart failure with preserved ejection fraction.

Methods

This study was a prospective, multicenter, open-label, randomized-controlled trial, comparing luseogliflozin 2.5 mg once daily or voglibose 0.2 mg three times daily in patients with type 2 diabetes suffering from heart failure with preserved ejection fraction (left ventricular ejection fraction >45% and BNP ≥35 pg/ml2) in a 1:1 randomization fashion. Randomization was undertaken using a computer-generated random sequence web response system. The primary outcome was the difference from baseline in BNP after 12 weeks of treatment between two drugs. The key secondary outcomes were the change from baseline in left ventricular ejection fraction and E/e' in echocardiographic parameters, body weight, glycohemoglobin level after 12 weeks of treatment. The safety outcomes included the incidence of major adverse cardiovascular events, hypoglycemic adverse events, and urinary tract infection.

Results

Between December 2015 and September 2018, 173 patients from 16 hospitals and clinics have been included in this study. Of those, 83 patients were assigned to receive luseogliflozin and 82 to receive voglibose. There was no significant difference in the reduction in the BNP concentration after 12 weeks from baseline between the two groups; the ratio of the average values at week 12 to the baseline value was 0.91 in the luseoglifllzin group as compared with 0.98 in the voglibose group (percent change, −9.0% vs. −1.9%, ratio of change with luseogliflozin vs. voglibose, 0.93; 95% confidence interval, 0.78 to 1.10; p=0.26). The key secondary outcomes including left ventricular ejection fraction, E/e', body weight, glycohemoglobin level and the safety outcomes did not differ significantly between the two groups.

Conclusions

In type 2 diabetes patients with heart failure with preserved ejection fraction, the administration of luseogliflozin did not lead to a significant reduction in the BNP concentration than that of voglibose. Left ventricular ejection fraction, E/e', body weight and glycohemoglobin level after 12 weeks of treatment, comparing with at baseline did not differ significantly between the two groups. (UMIN Clinical Trial Registry number, UMINehz748.005618395)

Acknowledgement/Funding

Novartis

In vitro and clinical evaluation of optical coherence tomography for the detection of subgingival calculus and root cementum

This study evaluated the effectiveness of swept-source optical coherence tomography (ss-OCT) for detecting calculus and root cementum during periodontal therapy. Optical coherence tomography (OCT) images were taken before and after removal of subgingival calculus from extracted teeth and compared with non-decalcified histological sections. Porcine gingival sheets of various thicknesses were applied to the root surfaces of extracted teeth with calculus and OCT images were taken. OCT images were also taken before and after scaling and root planing (SRP) in human patients. In vitro, calculus was clearly detected as a white-gray amorphous structure on the root surface, which disappeared after removal. Cementum was identified as a thin, dark-gray layer. The calculus could not be clearly observed when soft tissues were present on the root surface. Clinically, supragingival calculus and cementum could be detected clearly with OCT, and subgingival calculus in the buccal cervical area of the anterior and premolar teeth was identified, which disappeared after SRP. Digital processing of the original OCT images was useful for clarifying the calculus. In conclusion, ss-OCT showed potential as a periodontal diagnostic tool for detecting cementum and subgingival calculus, although the practical applications of subgingival imaging remain limited.

MicroRNA profiling in gingival crevicular fluid of periodontitis-a pilot study

Periodontitis is a chronic inflammatory disease that affects the interface of teeth and surrounding tissues. Gingival crevicular fluid (GCF) is an exudate of the periodontal tissues and can be collected from the gap between the tooth and gum (gingival sulcus or periodontal pocket) with paper strips. Testing of GCF is a low‐cost and minimally invasive procedure. In a variety of diseases, microRNAs (miRNAs) in body fluids are implicated in pathogenesis, and are suggested as potential diagnostic biomarkers. Here, we profiled miRNAs in GCF (two chronic periodontitis, one aggressive periodontitis, and five healthy subjects) using miRCURY LNA™ Universal RT microRNA PCR System, which yielded quantitative measures of more than 600 miRNAs. Through this analysis, we found that miRNA profiles in GCF of periodontitis patients are distinct from those of healthy controls. We further selected 40 miRNAs and confirmed their differential expression patterns in different subjects (five chronic periodontitis, one aggressive periodontitis, and six healthy subjects) using a custom miRNA PCR panel. This is the first demonstration of miRNA profiling in GCF and its alteration in periodontitis. Our findings suggest that a subset of miRNAs in GCF holds potential as a biomarker for periodontitis.

High-frequency low-level diode laser irradiation promotes proliferation and migration of primary cultured human gingival epithelial cells

In periodontal therapy, the use of low-level diode lasers has recently been considered to improve wound healing of the gingival tissue. However, its effects on human gingival epithelial cells (HGECs) remain unknown. The aim of the present study was to examine whether high-frequency low-level diode laser irradiation stimulates key cell responses in wound healing, proliferation and migration, in primary cultured HGECs in vitro. HGECs were derived from seven independent gingival tissue specimens. Cultured HGECs were exposed to a single session of high-frequency (30 kHz) low-level diode laser irradiation with various irradiation time periods (fluence 5.7-56.7 J/cm(2)). After 20-24 h, cell proliferation was evaluated by WST-8 assay and [(3)H]thymidine incorporation assay, and cell migration was monitored by in vitro wound healing assay. Further, phosphorylation of the mitogen-activated protein kinase (MAPK) pathways after irradiation was investigated by Western blotting. The high-frequency low-level irradiation significantly increased cell proliferation and [(3)H]thymidine incorporation at various irradiation time periods. Migration of the irradiated cells was significantly accelerated compared with the nonirradiated control. Further, the low-level diode laser irradiation induced phosphorylation of MAPK/extracellular signal-regulated protein kinase (ERK) at 5, 15, 60, and 120 min after irradiation. Stress-activated protein kinases/c-Jun N-terminal kinase and p38 MAPK remained un-phosphorylated. The results show that high-frequency low-level diode laser irradiation promotes HGEC proliferation and migration in association with the activation of MAPK/ERK, suggesting that laser irradiation may accelerate gingival wound healing.

Calculation of personal dose equivalent for positron-emitting radionuclides using Monte Carlo code EGS5

The conversion coefficients, H'(d,α)/Φ, for monoenergetic positrons and positron-emitting radionuclides were calculated by using the user code UCICRPM of the Monte Carlo code EGS5 to estimate the radiation dose for medical staff involved in positron emission tomography examinations. From these coefficients, the dose equivalent rates per unit activity at 0.07 and 10 mm depths in a soft tissue for a straight-line source of 2-deoxy-2-[(18)F]fluoro-d-glucose ((18)F-FDG) were calculated by using the developed user code UCF18DOSE. The dose equivalent rates per unit activity at 0.07 and 10 mm depths were measured by using a personal dosemeter (DOSE(3)) under the same conditions as those considered in the calculation. The calculated dose equivalent rates per unit activity at 0.07 and 10 mm depths were 0.116 and 0.0352 pSv min(-1) Bq(-1), respectively, at 20 cm from the (18)F-FDG injection tube.

Shape-memory alloy loop snare for endoscopic photodynamic therapy of early gastric cancer

BACKGROUND AND STUDY AIMS

Photodynamic therapy (PDT) has proved effective in the treatment of gastric cancer, but there is room for improvement. To achieve the technical goal of carrying out endoscopic PDT, endoscopists need to determine the precise area for laser irradiation at adequate dosages. This report describes the use of a shapememory alloy (SMA) loop snare as a useful tool in endoscopic PDT.

PATIENTS AND METHODS

Eleven patients with biopsy-proved early gastric cancer were treated with endoscopic PDT after intravenous injection of Photofrin II (2 mg/kg b.w.). Five patients underwent PDT using the SMA loop snare, and six underwent PDT without the use of the device. Cancer lesions smaller than 2 cm in diameter were irradiated with an excimer-dye laser (4 mJ, 80 Hz, 630 nm) for 20 min.

RESULTS

All five patients (100%) treated with PDT using the SMA loop snare, and four of the six patients (67%) treated with PDT without use of the SMA loop snare, showed complete remission.

CONCLUSIONS

The SMA loop snare routinely forms a circle 2 cm in diameter, covering an area of 3.14 cm2, and makes it possible to mark and calculate the precise area of cancerous lesions for irradiation at appropriate dosages. The findings of this study suggest that the SMA loop snare is an effective tool for PDT in early gastric cancer.

Early and delayed Tc-99m ECD brain SPECT in SLE patients with CNS involvement

We compared early and delayed Tc-99m ECD SPECT scans in 32 SLE patients (Group 1, definite neuropsychiatric disorders; Group 2, minor neurologic symptoms or normal) with those of normal controls by visual inspection and semi-quantitative evaluation. With visual interpretation, 13 out of 14 patients in Group 1 (93%) and 7 out of 18 patients in Group 2 (39%) had diffuse uneven decrease in early scans. Seven patients in Group 2 (39%) who had normal early scans demonstrated focal decrease in the medial frontal lobe in delayed scans. With cerebral region to cerebellar ratios, in early scans, the medial frontal lobe in Group 1 and Group 2 was significantly lower than in normal controls, and lateral frontal lobe and occipital lobes in Group 1 were significantly lower than in normal controls. Nevertheless, in delayed scans, every cortical region except for the parietal lobe in Groups 1 and 2 was significantly lower than in normal controls. The retention rates in all regions in SLE patients were significantly lower than in normal controls. No case showed SPECT improvement on follow-up studies in either group in spite of clinical improvement. Delayed Tc-99m ECD brain SPECT of high sensitivity might be useful in detecting CNS involvement. Although the SPECT findings did not correlate with the neuropsychiatric symptoms, early and delayed Tc-99m ECD SPECT seems to provide useful objective diagnostic information in SLE patients.

Evaluation of asialoglycoprotein receptor imaging agent as a marker of hepatic ischemia-reperfusion injury and recovery

Protection of hepatocytes from ischemia-reperfusion injury is a clinically important issue. The purpose of this study was to evaluate changes in acute liver damage and recovery after ischemia-reperfusion in rats with asialoglycoprotein receptor (ASGP-R) ligand. Ischemia was induced by clamping the hepatoduodenal ligament for 90 min. At 1, 3, 24, 48 hr, 1 and 2 wk after reperfusion, I-125-GSA was injected. Five min after injection, blood samples were obtained and the liver was removed. Several regions from each lobe were dissected, weighed and counted. Mean uptakes (% dose/g) in the liver and blood samples were calculated. Histologic sections stained with hematoxylin-eosin (H-E) stain showed ischemic damage at 1 and 3 hr, and focal hepatocyte necrosis at 24 hr. Predominant massive necrosis was not seen. The mitotic index with H-E stain and proliferating cell nuclear antigen (PCNA) labeling index were highest at 1 wk, indicating liver regeneration. At 1 and 3 hr, liver uptake was significantly decreased, and blood uptake was significantly increased, indicating decreased tissue blood flow and ischemic damage. Liver uptake showed significant increases at 48 hr and 1 wk, and was the highest at 1 wk, indicating liver regeneration during the convalescence stage. ASGP-R binding may provide valuable information on ischemia-reperfusion injury and recovery.

[Synchronization between preverbal vocal behavior and motor action in early infancy. II: An acoustical examination of the functional significance of the synchronization]

Normal infants start to produce canonical babbling (CB) at the age of 6 to 10 months. CB consists of reduplicated sequences of consonant-vowel syllables which have adult-like acoustical features. Therefore, onset of CB is considered to be a landmark in the development of spoken language. The previous study indicated that a behavioral synchronization of vocalizations with rhythmic actions occurred in infants before the onset of CB. The present study examined the function of synchronization. Acoustical analyses were conducted on vocalizations of four infants during three-months-period including the month when synchronization occurred most frequently. The results show that both utterance length and formant frequency transition duration of synchronized vocalizations are shorter than those of non-synchronized vocalizations. These acoustical features, which are required to produce CB, persisted even after the synchronization has disappeared. The present study suggests that synchronization of vocalizations with rhythmic actions has the function of prompting infants to produce CB.

Developmental changes of gene expression in heme metabolic enzymes in rat placenta

Transcription levels of the non-specific delta-aminolevulinate synthase (ALAS-N) and heme oxygenase-1 (HO-1) in the placenta at the terminal stage of pregnancy were comparable to those in the female adult liver and in the spleen, respectively. Immunohistochemical studies demonstrated that both enzymes were exclusively expressed in the trophoblast. During gestation, transcript of ALAS-N slightly increased, while HO-1 mRNA significantly decreased. Induced acute fetal hypoxia resulted in an increase in ALAS-N mRNA and in a decrease in HO-1 mRNA. These findings indicate that placental heme metabolism is influenced by the oxygen supply.

Relationship between rhythmic behavior and canonical babbling in infant vocal development

The onset of canonical babbling (CB) is a landmark event in infants' vocal development for spoken language. Previous research has suggested that the onset of CB coincides with the peak period of rhythmic activities. To examine this phenomenon in detail, 28 Japanese infants (14 girls, 14 boys) were observed longitudinally from the age of 5 to 9 months. In the experimental sessions, an audible or an inaudible rattle was placed into a hand of each tested infant. Then the number of times that the infant shook the rattle was counted. In the observational sessions, infants' spontaneous rhythmic activities under natural conditions were observed. The result shows that rhythmic activities reached their peak around the onset of CB. When the infants began to babble, they shook whichever rattle was in their hand, regardless of its audibility. After this period, they shook the audible rattles more frequently than the inaudible ones. These findings suggest that, around the onset of CB, infants learn to control their motor activities based on auditory feedback.

[Synchronization between preverbal vocalizations and motor actions in early infancy. I: Pre-canonical babbling vocalizations synchronize with rhythmic body movements before the onset of canonical babbling]

This study reports the synchronization between vocal behaviors and motor actions in infants at the prelinguistic stage. Four Japanese infants were studied from the age of 4-6 months to 11 months. For all infants, a 40-min segment was selected from the 60-90 min observation recording taken on each month. All the vocalizations and motor actions recorded in the segment were transcribed. The results show that a behavioral synchronization occurred between vocalizations and rhythmic actions in infants at the prelinguistic stage. The synchronization was particularly obvious in the month immediately before the onset of canonical babbling. These findings suggest that the synchronization between vocalizations and rhythmic actions may have the function of promoting infants to produce canonical babbling, that is indispensable for the acquisition of spoken language.

[Evaluation of the clinical usefulness of super dynamic 99mTc-HM-PAO SPECT in ischemic cerebrovascular disease--detection of hypo- and hyperperfusion area]

The purpose of this study is to assess the clinical usefulness of super dynamic SPECT of 99mTc-HM-PAO. Six patients with unilateral occlusion of middle cerebral artery (MCA) or internal carotid artery (ICA) in the chronic phase, and 5 patients with subacute cerebral infarction were studied. We used a ring-type SPECT "HEADTOME." Two types of collimator were used: a high sensitivity (HS) collimator for super dynamic scan and a high resolution (HR) collimator for static scan. First, the intravenous constant infusion of 99mTc-HM-PAO (925-1480 MBq) for 1 minute was started. After 30 seconds from the beginning of the injection, we performed the 12 seconds/frame super dynamic SPECT for 2 minutes. Then, the static SPECT for 10 minutes was done. For semiquantitative analyses, differential percentage of regional activity between affected and non-affected hemispheres was calculated in the 6th frame image of super dynamic SPECT and static SPECT image. In all 6 patients with unilateral occlusion of MCA and ICA, super dynamic SPECT images showed the better contrast of low perfusion areas in comparison with the static SPECT images. In 5 patients with subacute cerebral infarction who showed focal hyperactivities on static SPECT, focal hyperactivities (hyperperfusion or hyperemia) were displayed in 3 cases, whereas, focal hypo- or isoactivities (hypo- or isoperfusion) were shown in 2 cases on super dynamic SPECT. However, all patients with subacute cerebral infarction showed hyperfixation on static SPECT as compared with super dynamic SPECT. Although the image quality on super dynamic SPECT is not as high as that on static SPECT, cerebral hemodynamics would be detected with less backdiffusion of 99mTc-HM-PAO from the brain to blood, and with less accumulation of hydrophilic components in subacute infarct region. In conclusion, super dynamic SPECT in early distribution of 99mTc-HM-PAO using dedicated SPECT device might be helpful to detect cerebral perfusion close to true cerebral blood flow distribution.

Effect of intracellular free calcium mobilization on aggregation of umbilical cord blood platelets

Aggregation activity of platelets in umbilical blood is lower than that in adult blood, but the reason for this is not well understood. It has recently been clarified that calcium plays a role as a second messenger of platelet aggregation, and that glycoproteins of platelet surface membrane such as glycoprotein I b and IIb/IIIa are receptors for agonists inducing aggregation. We examined the concentrations of intracellular calcium and the membrane glycoproteins of platelets in umbilical and adult blood. The increase of intracellular calcium in umbilical platelets was lower than that in adult platelets when the aggregation was induced by ADP, collagen, thrombin and epinephrine. Only calcium ionophore A23187 induced aggregation of both umbilical and adult platelets. On the other hand, there were no qualitative differences between glycoproteins I b and IIb/IIIa of these two groups. Therefore, the low aggregation activity of umbilical platelets seems to be due to low responsiveness of the intracellular calcium system, not to the disorder of functional surface membrane glycoprotein.

Developmental changes in P300 wave elicited during two different experimental conditions

Age-related correlations on auditory event-related potentials were studied using a task-relevant oddball paradigm in 175 normal subjects aged 4-21 years and age-related correlations in the "ignore" condition were studied in 108 normal subjects aged 1-21 years. In the ignore condition, subjects more than 4 years of age were instructed to read a book to divert attention from the auditory stimulus. From 4 to about 17 years of age, the latencies of task-relevant P300 in event-related potentials (ERPs) gradually shortened. In the ignore condition experiment, the P300 latency shortened progressively, but stabilized at about 12 years of age. Whereas P300 in the ignore condition likely corresponds to P3a described previously (passive attention), the conventional P300 wave corresponds to P3b (active attention). The findings indicate a developmental difference between the P3a and P3b potential.

[Effectiveness of haloperidol in the treatment of chorea minor]

Chorea minor is the most curious manifestation of rheumatic fever, first described by Sydenham in 1686. Subsequent evidence showed that chorea could be a late manifestation of rheumatic fever, often occurring several months after a streptococcal infection in contrast to other major manifestations. During the ten-year period between 1984 and 1993, 11 children with rheumatic fever were seen at our hospital, two cases of these being accompanied with chorea minor. Case 1, a male aged 12, presented with involuntary movements. He was diagnosed as having rheumatic fever because of chorea and systolic ejection murmur at the apex of the heart. Plain cranial CT was normal. However, positron emission computed tomography revealed an increased 11C-glucose uptake in the caudate nucleus as compared with the cerebral cortex. Case 2, a female aged 14, presented with involuntary movements. Plain cranial CT was normal, but single photon emission CT showed a difference between the right and left brain. These two patients were given penicillin G (PCG), predonisolone (PSL) and haloperidol. Haloperidol was administered, because PCG and PSL had no effect to improve the clinical manifestations. After administer decreased to a half with a clinical improvement, but the level of GABA did not change. Haloperidol seemed to be an effective and useful agent for motor manifestations of the disease.

[The administered activity of radionuclides in nuclear medicine--rational reduction of medical radiation exposure]

A survey of 104 hospitals was conducted to determine the administered activity of radionuclides. Eighty-five hospitals responded, and reported a total of 119,614 examinations in one year. The examinations included: bone scintigraphy, 26.4%; Thallium-201 (201Tl) myocardial scintigraphy, 15.5%; Gallium-67 (67Ga) scintigraphy, 13.3%; N-isopropyl-p-[123I]iodoamphetamine (IMP) brain perfusion scintigraphy, 7.0%. The administered activity was corrected by body weight only for children at more than 80% of the responding hospitals. The number of hospitals that reported over-administration of radionuclide varied according to the type of scintigraphy performed: bone, 76%; inflammatory (67Ga), 93%; myocardial (201Tl), 89.2%; brain (IMP), 8.5%. The administered activity of IMP was closer to the upper limits specified in the Recommendations on Standardization of Radionuclide Imaging by the Japan Radioisotope Association (1987), because IMP is very expensive and is supplied as single vials. The highest average effective dose was for myocardial scintigraphy, the second-highest for inflammatory scintigraphy, and the third-highest for bone scintigraphy. In 201Tl and 67Ga scintigraphy, the entire contents of the vial may be administered two days before the expiration date, because the ratio of (true patient administered activity) to (declared patient administered activity) is similar to the ratio of (radioactivity on the day of supply) to (radioactivity on the day of expiration). The factors that influence administered activity are throughput, price of the radionuclide, and whether the radionuclide is sold as a single vial. In order to decrease the effective dose, it is necessary to establish a close cooperation between medical personnel, the makers of radiopharmaceuticals, and manufacturers of gammacameras.

[The study of mismatch negativity]

We studied age related correlations of mismatch negativity (MMN) auditory event-related potentials (ERPs) using odd ball paradigm in 121 normal subjects (from 6 months to 43 years) and 33 mentally retarded subjects (from 2 to 18 years). The subject was instructed to read a book in order to ignore the stimulus during the experiment, or no specific task was imposed on young child. The MMN wave form was clearly obtained in normal 6 month old subjects. As the age advanced from 6-months, the latencies of MMN progressively shortened till about 7 years, when the latency reached adult level. One-third of mentally retarded patients had prolonged MMN than that normal age-matched subjects. Reliable recording of P300 requires subject's cooperation and attentiveness, which are difficult to achieve in young children or mentally retarded patients. MMN may be utilized in children to evaluate the development of the cognitive function.

Effect of taurine concentration on platelet aggregation in gestosis patients with edema, proteinuria and hypertension

To elucidate the relationship between the high concentration of taurine in platelets and platelet aggregation in patients with EPH gestosis (gestosis with edema, proteinuria and hypertension), platelet aggregation and the platelet release response (release of ATP and beta-thromboglobulin) were studied in the washed platelet suspension (PS) obtained from normal pregnant or non-pregnant women and EPH gestosis patients. Platelet aggregation and platelet release response were significantly lower in EPH gestosis patients than in normal pregnant and non-pregnant women. Platelet aggregation, platelet release response induced by ADP and collagen and the aggregation induced by A23187 were inhibited in taurine-loaded PS from non-pregnant women. These results suggest that the decrease of platelet aggregation in EPH gestosis patients was caused by high concentrations of taurine in platelets, which may inhibit the intracellular Ca2+ movement and platelet release response. Therefore, taurine appears to have a protective effect against the hyper-coagulative state in EPH gestosis.

Concentration and uptake of taurine in umbilical blood platelets

The concentration and uptake of taurine in the umbilical and adult blood platelets were studied. Taurine was the most abundant free amino acid in both umbilical and adult blood platelets. The taurine concentration in umbilical blood platelets (2.30 pmoles/10(4) cells) was significantly lower than that of adult blood platelets (3.27 pmoles/10(4) cells) in contrast to the reverse relationship in taurine concentrations in umbilical and adult blood plasma. No other amino acid showed such significant difference in the concentrations between umbilical and adult blood platelets. Taurine uptake into umbilical blood platelets was temperature sensitive and sodium-dependent in a manner similar to that of adult blood platelets. The uptake conformed well to Hanes-plot. The Vmax of the uptake into adult blood platelets was about 3.6 times higher than that of umbilical blood platelets, but no significant difference was seen in the Km value between the two groups.

Platelet taurine concentration and uptake in gestosis patients with edema, proteinuria and hypertension

The taurine concentration and uptake in platelets obtained from normal pregnant women and gestosis patients with edema, proteinuria and hypertension (EPH gestosis) were investigated. The taurine concentration in platelets showed a marked increase in severe EPH gestosis compared with normal pregnancy or mild and moderate EPH gestosis, while the plasma taurine concentration did not change significantly. Taurine uptake in platelets paralleled the severity of EPH gestosis. The Vmax of the uptake in severe EPH gestosis was about 2.4 times higher than that in normal pregnancy or mild and moderate EPH gestosis, but no significant difference was seen in the Km value among these groups.

Effect of the cooling rate on insulin release from frozen-thawed In-111 cells

Cultured cells derived from hamster insulinoma (In-111 R1 cells) were placed in 1.4 M dimethyl sulfoxide (Me2SO)-containing RPMI 1640 at 20 degrees C for 20 min. They were frozen to -40 degrees C at a cooling rate of 1.0 or 0.5 degrees C/min, subsequently to -80 degrees C at 3 degrees C/min with a programmable freezer. After being maintained at -80 degrees C, they were rapidly thawed to 37 degrees C. Thawed cells were washed with 0.75 M sucrose for removal of Me2SO. Recovered cells were cultured in 2 ml of RPMI 1640 with 1.3 mM theophylline under a gas phase of 95% air -5% CO2 at 37 degrees C for 2 days. In both cooling rates, frozen-thawed cells discharged more insulin than the thawed in the absence of theophylline. However, this released insulin level was higher in the cells frozen at a cooling rate of 0.5 degrees C/min than that at 1.0 degrees C/min. Moreover, insulin released from frozen-thawed hamster insulinoma cells increased significantly with the addition of 1.3 mM theophylline. Considering that the higher insulin release level at 11.1 mM glucose alone might indicate cellular damage, it is suggested that the cooling rate of 1 degree C/min may be better for cryopreservation of the dispersed cells under the present protocol for the assessment of the function of insulin release.

[The influence of the time activity variation on dynamic SPECT images in camera based SPECT]

Image quality of dynamic single photon emission computed tomography (SPECT) using a rotating gamma camera is dependent on the time activity variation of the tracer such as accumulation and excretion in the object's organ. Especially at the early time after injection of radionuclide, artifacts may occur strongly in the SPECT images. Simulated and experimental projection data of line sources and Jaszczak phantom were altered by sequentially weighting the projections with a function that varied linearly with time. With a variation of object activity given by linearly decaying functions, the main effect observed on the SPECT images obtained from simulated line sources was an elliptical deformation on the object. If the changing rate (R (t + 1)-R(t))/R(t) x 100 remained within 20% during acquisition, this deformation of SPECT images of line sources was not noticeable visually and resolution (FWHM) of line sources scarcely was degraded. In renal dynamic SPECT study using 99mTc-DTPA, the image quality of the first scan (30 sec) was considerably degraded. However, the changing rates after the third scan were less than 20% on the mean of 10 kidneys and the image quality was not noticeable visually.

Photodynamic therapy for early gastric cancer using a pulsed gold vapor laser

Endoscopic photodynamic therapy (PDT) using a pulsed gold vapor laser (wavelength 628 nm, LaserSonics Inc.) was performed on eight cases of early gastric cancer. Three patients refused to have surgery, and the others were in a high-risk group due to old age or complications with other diseases. Hematoporphyrin derivative (HpD I, 2.5-3 mg/kg, Photofrin Inc.) was injected intravenously, and 48-72 hours later, the entire cancer lesion and 5 mm width mucosa encircling it were irradiated with a gold vapor laser through a single quartz fiber. The irradiation was delivered at 300-330 mW for 5-20 minutes, which gave about 90 J/cm 2 dosage. In seven of eight cases, local cure was achieved. Recurrence was noted only in one patient. In one of eight patients, operation was carried out 1 month after PDT. Pathological examination of the resected stomach revealed that the effect of PDT extended into the tunica muscularis propria. Side effects of HpD, such as skin rash, were noted in two patients, but no serious complications of PDT were encountered. This suggests that PDT with a pulsed gold vapor laser is clinically useful in the treatment of early gastric cancer.

Heterogeneity of islet cell autoantibodies in terms of insulin release from rat islets and insulinoma cells

The clinical significance of cytoplasmic islet cell autoantibodies (ICA) has been studied since their discovery by Bottazzo et al. in 1974. Some ICAs destroy pancreatic B cells in the presence of complement, whereas others take no part in this destruction. This suggests that islet function varies with the amount of ICA produced. In the present investigation we report the heterogeneity of monoclonal islet cell antibodies produced by one of us in terms of insulin release from isolated rat islets as well as from rat insulinoma cells (RINr).

Possible involvement of cholinergic nicotinic receptor in insulin release from isolated rat islets

Insulin release is influenced by the autonomic nervous system. Regarding parasympathetic control, previous reports have shown that regulation of insulin release is executed exclusively through muscarinic receptors in the pancreatic islets. In the present study, however, we examined the effect on insulin release at the islet level of various agents affecting the parasympathetic nervous system, especially nicotinic receptor blockers. Pancreatic islets isolated from adult Wistar male rats were incubated with these agents and insulin release in the media was measured. Acetylcholine chloride (10(-5) M), as well as distigmine bromide (10(-6), 10(-5) M), both of which are cholinesterase inhibitors, stimulated insulin release, whereas atropine (5 x 10(-6), 5 x 10(-5) M) suppressed it. On the other hand, serum and IgG from myasthenia gravis patients, containing anti-acetylcholine receptor antibodies, affected insulin release, and alpha-bungarotoxin (10(-9)-10(-7) M), a nicotinic receptor blocker, stimulated insulin release dose-dependently. The present observations suggest that insulin release is influenced by the parasympathetic nervous system, mediated via not only muscarinic but also nicotinic receptors.

Cerebral hemodynamics in patients with chronic obstructive carotid disease by rCBF, rCBV, and rCBV/rCBF ratio using SPECT

To evaluate cerebral hemodynamics, 21 patients with chronic occlusion or severe stenosis of the internal carotid or middle cerebral artery with normal or only lacunar infarction on x-ray CT were studied using single photon emission computed tomography (SPECT). We measured rCBV with 99mTc erythrocytes after rCBF with 133Xe, and calculated rCBV/rCBF. rCBF and rCBV of the 25 affected hemispheres were classified as (a) patients with normal rCBF [type I (n = 7) and type II (n = 3)]; (b) patients with decreased rCBF [type III (n = 6) and type IV (n = 9)]. These two groups then could be subdivided according to findings of rCBV, normal, and increased blood volumes. rCBV/rCBF increased as the cerebral perfusion pressure dropped from type I to type III. In type IV, other situations but cerebral autoregulation could be assumed. rCBV/rCBF signifies vascular mean transit time. Type III (high rCBV/rCBF) assumed as the increased OEF, misery perfusion as reported in PET. We propose rCBF, rCBV and rCBV/rCBF using SPECT can be an index for cerebral circulatory reserve.

Lack of favorable effect of immunomodulators on outbred syngeneic rodent islet transplantation

We studied the effect of two immunomodulators, lobenzarit disodium and OK-432, on outbred syngeneic islet transplantation. Six hundred fresh islets taken from two male Wistar rats were transplanted intraportally into other male Wistar rats that had been made diabetic with streptozotocin. Lobenzarit was given to 12 recipients and OK-432 to seven recipients intraperitoneally for 1 month, while nine controls received only intraperitoneal saline. Both drug-treated groups could not maintain lower fasting plasma glucose levels or higher fasting body weights at each time as compared with controls. The islet survival time in lobenzarit-treated (23.5 +/- 8.0 days) and OK-432-treated (25.3 +/- 13.4 days) groups was not longer than that (21.6 +/- 9.4 days) of the control group. All the pancreatic insulin contents of the seven surviving controls, ten surviving lobenzarit and five surviving OK-432 recipients were less than 0.8% of the mean insulin content obtained from 12 normal male rats. The hepatic insulin content of both drug-treated groups was not higher than that of the control group. These results suggest that lobenzarit disodium and OK-432 cannot protect outbred syngeneic islet grafts.

[SPECT measurement of cerebral hemodynamics in transient ischemic attack patients--evaluation of pathogenesis and detection of misery perfusion]

To evaluate the cerebral hemodynamics and the pathogenesis by regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV), 42 transient ischemic attack (TIA) patients and 9 normal volunteers were studied using SPECT. We classified these patients into Group A (n = 23: no occlusion or stenosis of the internal carotid or middle cerebral artery; non large vessel disease) and Group B (n = 19: chronic occlusion or severe stenosis of the internal carotid or middle cerebral artery; large vessel disease). We obtained rCBF with 133Xe inhalation and rCBV with 99mTc-red blood cells. Of 9 normal volunteers aged 43-70 yr (mean age 59.8 +/- 8.3 yr), the mean rCBF was 45.8 +/- 5.1 (ml/100 g brain/min), the mean rCBV was 4.0 +/- 0.4 (ml/100 g brain). The examination was done by comparing the values of the affected hemispheres of Group A and Group B patients with the mean rCBF and the mean rCBV of normal volunteers. Eleven out of Group A patients and 15 out of Group B patients showed decreased rCBF. But of those patients, no patients of Group A showed increased rCBV and 6 out of 19 Group B patients showed increased rCBV. Thromboembolic mechanism which is of Group A patients and Group B patients without increased rCBV, and hemodynamic mechanism which is of Group B patients with increased rCBV were considered as the main cause of TIA. Decreased rCBF and increased rCBV in Group B patients can be assumed as the misery perfusion as reported in PET studies.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of cerebral hemodynamics by 123I-IMP in cerebral AVMs before and after operation by using SPECT]

To evaluate cerebral hemodynamics by N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) preoperative and postoperative (after 1 day, and after 7-10 days) regional cerebral blood flow scan, 6 arteriovenous malformations (AVMs) which performed total removal operations were studied by using a ring type SPECT "HEADTOME". We performed the dynamic scan just after the intravenous injection of 222 MBq (6 mCi) of 123I-IMP, then the static scan 20 minutes after the intravenous injection. In preoperative dynamic scans of all cases, only the first frame image showed the increased activity on the nidus probably because of the blood pool. Preoperative static scans of all cases showed the remarkable decreased activity on the nidus, and decreased activity surrounding the nidus probably because of the peripheral steal phenomenon. In postoperative scan of the next day, 4 out of 6 cases showed the transient decreased peripheral steal, particularly 2 out of those 4 cases showed the transient hyperperfusion probably because of the normal perfusion pressure breakthrough (NPPB). And, 2 out of 6 cases showed transient peripheral low perfusion on much larger area than those of the preoperative scans probably because of the focal brain damages and edemas. We conclude that 123I-IMP SPECT on AVM is very useful to decide the indication of the removal operation, and to estimate the postoperative risk, and to evaluate the preoperative and postoperative cerebral hemodynamic changes in the peripheral area of AVM.

Effect of cooling rate on insulin release from frozen-thawed dispersed rat islet cells

Rat islet cells, dissociated with EDTA-Dispase, were immersed in 10% dimethyl sulfoxide at 20 degrees C for 15 min and frozen to -40 degrees C at a cooling rate of 0.5 or 1.0 degree C/min and subsequently further to -80 degrees C at 3 degrees C/min by a programmable freezer. After being maintained at -80 degrees C for 10 min, they were rapidly thawed in a water bath at 37 degrees C. They were cultured for 12 h and preincubated in 3.3 mM glucose-containing Krebs-Henseleit bicarbonate buffer (KHBB) for 1 h. Groups of 10(4) cells were then incubated in 3.3 or 16.7 mM glucose-containing KHBB for another hour. As a control, non-frozen-thawed cultured islet cells were incubated similarly. The non-frozen rat islet cells released 1.29 pg insulin/cell.60 min in the presence of 3.3 mM glucose and this release level was significantly elevated to 1.64 pg insulin/cell.60 min in the presence of 16.7 mM glucose. The cells frozen at 0.5 degree C/min releasing 1.55 pg insulin/cell.60 min in the presence of 3.3 mM glucose also responded to 16.7 mM glucose and released the significantly high level of 1.87 pg insulin/cell.60 min. However, the islet cells frozen at a cooling rate of 1 degree C/min secreted 1.74 and 1.92 pg insulin/cell.60 min in the presence of 3.3 mM and 16.7 mM glucose respectively. There was no significant difference between these levels. These results indicate that cryopreservation at a cooling rate of 0.5 degree C/min may be adequate for the preservation of dispersed pancreatic endocrine cells.

Vacor inhibits insulin release from islets in vitro

It has been reported that Vacor, a rodenticide containing N-3-pyridylmethyl-N'-p-nitrophenyl urea, causes insulin-dependent diabetes mellitus. The pathomechanism of Vacor-induced diabetes mellitus has not been clarified yet. The effect of Vacor, therefore, was studied in terms of insulin release from isolated rat pancreatic islets. Vacor suppressed glucose-stimulated insulin release, but did not affect the insulin release induced by theophylline or 12-o-tetra-decanoylphorbol 13-acetate. It is suspected that the suppression of insulin release from pancreatic islets by Vacor may contribute to the pathogenesis of Vacor-induced diabetes mellitus and that this suppression might not be related to cAMP and C-kinase.

Effect of dimethylthiourea on syngeneic rodent islet transplantation

We studied the effects of a hydroxyl radical scavenger, dimethylthiourea (DMTU), on syngeneic islet grafts. Six hundred fresh islets taken from two Wistar rats were transplanted intraportally into other Wistar rats made diabetic with streptozotocin. DMTU was given to five recipients intraperitoneally for a month while nine controls received only intraperitoneal saline. The DMTU-treated group had significantly lower fasting plasma glucose levels at 1.5, 4.5, 5, 5.5, 6, 7, 9 and 11 weeks and had higher mean fasting body weights between the 2.5th week and their eventual sacrifice. Their islets also survived significantly longer than did those of the controls (73.6 +/- 3.4 vs. 21.6 +/- 9.4 days). This suggests that oxygen free radical production endangers graft survival and that the hydroxyl radical scavenger DMTU protects syngeneic islet grafts.

Sophisticated mesh filtration technique of a large-scale isolation of islets and their function

A large-scale isolation of islets is required for islet transplantation. We improved our conventional method, and could obtain about three times more islets than by the conventional methods. Pancreata of adult Wistar rats were inflated by injection of buffer with (A) or without 1.3 mg/ml collagenase (B). The rats were bled from the inferior vena cava and the aorta in (A) simultaneously with the inflation. They were further digested with collagenase and filtered through two different meshes (pore size: 1190 and 590 microns) (A1) or three different meshes (pore size: 1190, 590 120 microns) (A2) in order. Insulin released from islets isolated in this manner was determined by 1-h incubation with 3.3 and 16.7 mM glucose. Besides, 600 islets each were transplanted into the liver of streptozotocin-induced diabetic Wistar rats and their fasting plasma glucose was measured at weekly intervals. (1) With these methods more numerous islets were harvested by A1 (mean: 554) and A2 (mean: 746) than B (mean: 224). (2) Insulin released at both glucose concentrations was similar among islets obtained by A1, A2 and B. (3) The plasma glucose-lowering effect was similar among the islets obtained by these methods. (4) A more selected range of islet sizes was obtained by A2 than A1. These observations indicate that the present techniques (A1 and A2) are less time-consuming and simpler for a large-scale isolation of islets.

Islet function after storage at -2 degrees C and -196 degrees C

The radical treatment of type 1 diabetes by transplantation requires the extracorporeal storage of islets, and this has frequently been studied. Damage from ice formation, however, has prevented the development of any satisfactory method for preservation. We compared islet function after frozen storage with that after non-frozen storage. Isolated rat islets immersed in 10% dimethyl sulfoxide were kept at -2 degrees C (group A) and -196 degrees C (group B) for 7 days. After one day of culture, some of the islets were incubated in 3.3 and 16.7 mM glucose-containing Krebs--Henseleit bicarbonate buffer for 60 min. The other islets were incubated with 3H-leucine for 2 h. The radioactivity of whole-islet homogenate and the insulin extracted from it were measured. We also counted the number of islets before and after the 7-day storage. The islets thus preserved were transplanted into streptozotocin-induced diabetic rats and the fasting plasma glucose was determined weekly. Non-cooled islets were used as controls (group C). Insulin release in the presence of 16.7 mM glucose did not significantly differ between groups C and A, whereas it was lower in group B than in groups A or C. The islet uptake of 3H-leucine was lower in A and B compared with C, but the insulin synthesis was similar in all three groups. More islets were recovered from A than B. Fasting plasma glucose was lowered similarly in the diabetic rats after transplantation of islets from A and B. The relative ease of preservation at -2 degrees C, and the positive results of this experiment, favor this method of preservation.

Production of anti-insulin monoclonal antibody and its application to immunoassay of insulin and immunohistochemistry

An unlimited supply of suitable antisera is wanted for immunoassays, analysis of antigenic determinants and precise localization of antigens in biological systems. Therefore, we produced a monoclonal antiporcine insulin antibody by the hybridoma technology and assessed it in comparison with polyclonal antibody. The spleen cells of BALB/c mice immunized against porcine insulin were hybridized with mouse myeloma cells (P3-X63-Ag8-U1). The monoclonal antibody thus generated was shown to have high binding capacity and specificity to porcine insulin in radioimmunoassay. It reacted with human insulin as well, but did not crossreact with other polypeptide hormones produced in the pancreatic islets such as glucagon, somatostatin and pancreatic polypeptide. In immunohistochemistry human and dog islets were stained by this monoclonal antibody. Rat islets were not stained, although they reacted with polyclonal anti-insulin antibody. The insulin of human serum samples measured using the monoclonal antibody was tightly correlated with that using the polyclonal antibody. These observations indicate that our hybridoma-derived monoclonal antibody is useful for immunoassay as well as localization of insulin.

Participation of nicotinic receptor in hormone release from isolated rat islets of Langerhans

Pancreatic hormone release is generally thought to be regulated through adrenergic as well as muscarinic receptors. We have previously observed possible nicotinic involvement in insulin release. In the present study, we incubated isolated rat islets for 60 min with various concentrations of atropine (a muscarinic receptor blocker), alpha-bungarotoxin (alpha-Btx, a nicotinic receptor blocker), and anti-acetylcholine receptor antibody (IgG) (anti-Ach.R.Ab) obtained from a patient with myasthenia gravis. Atropine suppressed insulin release, and alpha-Btx and anti-Ach.R.Ab potentiated it; atropine did not suppress glucagon release, while alpha-Btx and anti-Ach.R.Ab raised it. None of these agents influenced somatostatin release. These observations suggest that muscarinic as well as nicotinic receptors influence insulin release, as nicotinic receptors do glucagon release. Neither nicotinic nor muscarinic receptors seem to regulate somatostatin release.

Production of anti-insulin monoclonal antibody and its clinical application

Hybridoma-produced monoclonal antibody (MoAb) against insulin is useful for insulin assays because of its specificity and plentiful supply. The spleen cells of male BALB/c mice immunized against monocomponent porcine insulin were hybridized with mouse myeloma cells (P3-X63-Ag8-U1). The resulting anti-insulin antibody (Ab) was purified and characterized by radioimmunoassay (RIA) using 125I-porcine insulin and sandwich-method enzyme immunoassay (EIA) using Ab-conjugated beads and beta-galactosidase. For reference, we used anti-insulin polyclonal antibody raised in guinea pigs (PoAb). Using the Ouchterlony technique, we identified the antibody as being of subclass IgG 1. We judged this antibody to be MoAb because it did not react at all with porcine insulin during EIA, in concentrations between 0 and 12.5 ng/ml; in contrast, PoAb reacted dose-dependently. During RIA, this Ab did not cross-react with glucagon, somatostatin or pancreatic polypeptide. It did cross-react with human and bovine insulins but not with rat insulin. The proper concentration of this MoAb for RIA proved to be 1:1,500,000 and the smallest detectable level of porcine insulin by RIA using this Ab was 0.5 ng/ml. These levels were similar to those obtained with PoAb. The binding activity of this MoAb to human insulin was quite similar to that of porcine insulin. RIA insulin determinations using our MoAb correlated well with those employing PoAb.

Complements in diabetes mellitus: activation of complement system evidenced by C3d elevation in IDDM

To characterize insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) in terms of the complement system, some components of the system as well as the related substances and indices were studied. CH50, C3, C4 and C3bINA significantly increased in both IDDM and NIDDM compared with non-diabetic healthy controls. ACH50 was also elevated in NIDDM, whereas it was similar in IDDM and controls. Besides, the serum concentration of C3d, a breakdown product of C3, was higher in IDDM than in NIDDM and healthy controls, but that in NIDDM did not differ significantly from the control. B1Hg1 was not different among IDDM, NIDDM and non-diabetic controls. These observations suggested that there is a high level of complements in both types of diabetes mellitus, but the complement activation seems to be much enhanced in IDDM compared with NIDDM.

Evaluation of cryopreservation techniques of pancreatic fragments and islets in vitro and in vivo

We evaluated cryopreservation techniques for pancreatic fragments and islets using rat tissue. After equilibration in 10% dimethyl sulfoxide (Me2SO), the tissue was frozen in a programmable freezer at 1 degree C/min down to -40 degrees C and at 3 degrees C/min down to -71 degrees C. The islets, when thawed, released abundant insulin in the presence of as little as 3.3 mM glucose, much more so than non-frozen islets did. Three additional procedures, prefreezing and post-thawing culture and the stepwise dilution of the Me2SO, lowered the non-specific insulin release of the thawed islets and improved their insulin response to 16.7 mM glucose. Thawed pancreatic fragments subjected to these additional procedures, transplanted into the peritoneal cavity of streptozotocin-induced diabetic rats, reduced their hyperglycemia significantly. The thawed fragments and islets did not differ from their corresponding non-frozen controls in 3H-leucine incorporation. The maintenance of tissue function was not satisfactory. However, our observations indicate that culturing pancreatic tissue before freezing and after thawing and the stepwise dilution of the cryoprotective agent reduce the damage induced by freezing the tissue.

Complements in non-insulin-dependent diabetes mellitus with complications

A relation of the complement system to the development of complications in non-insulin-dependent diabetes mellitus (NIDDM) was evaluated by measuring some components of the complement system. CH50, C3, C4 and C3bINA were significantly elevated in subjects with NIDDM as compared with healthy non-diabetic controls. However, CH50 and C3 did not differ between diabetics with and without complications. C4 was higher in diabetics with retinopathy as well as with retinopathy and neuropathy than in diabetics without these complications. ACH50, beta 1Hg1 and C3d were similar in subjects with NIDDM and non-diabetics, and not associated with complications of NIDDM. C3d/C3 in NIDDM without complications was lower than in healthy subjects, but did not significantly differ between the types of complications. These results suggest that the high level of complements in NIDDM might be due to enhanced production of complements and the development of diabetic complications would be related to the elevated level of complements.

An improved method for the isolation of islets from the rat pancreas

The conventional method for rat islet isolation was improved by injection of collagenase solution (1.3 mg/ml) into the bile duct and the concomitant dissection of the inferior vena cava, static incubation of the removed distended pancreas for 15 min at 37 degrees C and filtration of the digested tissue through two different meshes of 1190 and 590 micron in pore size. This new technique led to about 2.5 times higher yield of viable islets than the conventional method.

Non-frozen cold storage is favorable for islet function and morphology

Freezing has been shown to damage pancreatic islets and to disrupt their insulin release, probably because of intracellular ice formation. We compared frozen islets with fresh ones and with others stored at temperatures above freezing from a standpoint of insulin release response to glucose and transplantation. Group A islets, isolated from rats and immersed in 10% dimethyl sulfoxide in RPMI 1640, were stored at -2 degrees C, and group B islets at -196 degrees C, for 7 days. As for group B, the islets were cooled at 1 degree C/min from room temperature to -40 degrees C, subsequently at 3 degrees C/min to -80 degrees C and then put into liquid nitrogen to be rapidly frozen to -196 degrees C. The control islets were fresh. In vitro, basal release at 3.3 mM glucose was similar in group A to that in the controls, but was higher in group B than group A. Stimulated release against 16.7 mM glucose was lower in group A than group B. However, insulin responsiveness, i.e., the ratio of insulin release at 16.7 mM glucose to that at 3.3 mM glucose, was lost in group B. Freezing also caused damage to the group B cells visible under the light and electron microscopes, while group A islets were largely intact. In vivo, after 600 islets were transplanted into streptozotocin-induced diabetic rats, group A was better able to lower fasting blood glucose than was group B, and remained so for 4 weeks. Above sub-zero preservation in the non-frozen state thus seems adequate for the short-term storage for 7 days.