Photocrosslinkable chitosan as a biological adhesive

A photocrosslinkable chitosan to which both azide and lactose moieties were introduced (Az-CH-LA) was prepared as a biological adhesive for soft tissues and its effectiveness was compared with that of fibrin glue. Introduction of the lactose moieties resulted in a much more water-soluble chitosan at neutral pH. Application of ultraviolet light (UV) irradiation to photocrosslinkable Az-CH-LA produced an insoluble hydrogel within 60 s. This hydrogel firmly adhered two pieces of sliced ham with each other, depending upon the Az-CH-LA concentration. The binding strength of the chitosan hydrogel prepared from 30-50 mg/mL of Az-CH-LA was similar to that of fibrin glue. Compared to the fibrin glue, the chitosan hydrogel more effectively sealed air leakage from pinholes on isolated small intestine and aorta and from incisions on isolated trachea. Neither Az-CH-LA nor its hydrogel showed any cytotoxicity in cell culture tests of human skin fibroblasts, coronary endothelial cells, and smooth muscle cells. Furthermore, all mice studied survived for at least 1 month after implantation of 200 microL of photocrosslinked chitosan gel and intraperitoneal administration of up to 1 mL of 30 mg/mL of Az-CH-LA solution. These results suggest that the photocrosslinkable chitosan developed here has the potential of serving as a new tissue adhesive in medical use.

Construction of a new multi-turn time-of-flight mass spectrometer

A new type of multi-turn time-of-flight mass spectrometer was constructed, consisting of four cylindrical electric sectors and 28 electric quadrupole lenses, the size of the vacuum chamber being 60 x 70 x 20 cm. It was demonstrated that the mass resolution can be increased according to the number of cycles of the ions through the ion optical system.

Impeding O(2) unloading in muscle delays oxygen uptake response to exercise onset in humans

We tested whether the leftward shift of the oxygen dissociation curve of hemoglobin with hyperpnea delays the oxygen uptake (VO(2)) response to the onset of exercise. Six male subjects performed cycle ergometer exercise at a work rate corresponding to 80% of the ventilatory threshold (VT) VO(2) of each individual after 3 min of 20-W cycling under eupnea [control (Con) trial]. A hyperpnea procedure (minute ventilation = 60 l/min) was undertaken for 2 min before and during 80% VT exercise in hypocapnia (Hypo) and normocapnia (Normo) trials. In the Normo trial, the inspired CO(2) fraction was 3% to prevent hypocapnia. The subjects completed two repetitions of each trial. To determine the kinetic variables of VO(2) and heart rate (HR) at the onset of exercise, a nonlinear least-squares fitting was applied to the data averaged from two repetitions by a monoexponential model. The end-tidal CO(2) partial pressure before the onset of exercise was significantly lower in the Hypo trial than in the Con and Normo trials (22 +/- 1 vs. 38 +/- 3 and 36 +/- 1 mmHg, respectively, P < 0.05). The time constant of VO(2) and HR was significantly longer in the Normo trial (28 +/- 7 and 39 +/- 18 s, respectively) than in the Con trial (21 +/- 7, 34 +/- 16 s, respectively, P < 0.05). The VO(2) time constant of the Hypo trial (37 +/- 12 s) was significantly longer than that of the Normo trial, although no significant difference in the HR time constant was seen (Hypo, 41 +/- 28 s). These findings suggested that respiratory alkalosis delayed the kinetics of oxygen diffusion in active muscle as a result of the leftward shift of the oxygen dissociation curve of hemoglobin. This supports an important role for hemoglobin-O(2) offloading in setting the VO(2) kinetics at exercise onset.

Sex ratio distortion and severe inbreeding depression in the gypsy moth Lymantria dispar L. in Hokkaido, Japan

An abnormal female producing only female progeny was found in Lymantria dispar in Hokkaido, Japan, in July 1996. Similarly, its progeny produced only females. Egg hatch rates were near 50% in all-female matrilines. Therefore, a certain cytoplasmic factor was thought to kill males in eggs differentially, resulting in only female hosts. In the next generation, the field population was estimated to contain 9.1% abnormal females. Severe inbreeding depression was also observed in egg hatch rates during confirmation of maternal inheritance. The cost of inbreeding was estimated at 0. 395, which is one of the highest in insects. Inbreeding avoidance by their host has been cited as one of the advantages of a male-killing factor, but we suggest that this is not applicable in this moth.

Interaction between sodium ascorbate and polyphenols

The interaction between sodium ascorbate and polyphenols was investigated by two different parameters: radical intensity and cytotoxicity induction. ESR spectroscopy shows that sodium ascorbate, lignins (alkali-lignin, lignin sulfonate, pine cone-derived lignin) and tannins (gallic acid, epigallocatechin gallate (EGCg), tannic acid) all produced radicals with different intensities under alkaline conditions. All lignin samples significantly enhanced the radical intensity and cytotoxic activity of sodium ascorbate, whereas all tannin samples slightly reduced the radical intensity of sodium ascorbate. Sodium ascorbate efficiently scavenged the radical and cytotoxic activity of gallic acid, as expected by the ionization potential and heat of reaction by the PM3 semiempirical method. EGCg and tannic acid slightly reduced the cytotoxic activity of sodium ascorbate. The present study demonstrates that lignins and tannins modify the radical intensity and cytotoxic activity of sodium ascorbate in different manners, and suggests the applicability of ESR spectroscopy for the screening of drug to drug interaction.

Expression of a chitinase gene and lysis of the host cell wall during Chlorella virus CVK2 infection

A chitinase gene (vChti-1) encoded by the Chlorella virus CVK2 was cloned and characterized. The vChti-1 open reading frame consisted of 2508 bp corresponding to 836 amino acid residues. The predicted amino acid sequence contained two sets of a family 18 catalytic domain that is responsible for chitinase activity. Northern blot analysis revealed that the vChti-1 gene was expressed in virus-infected Chlorella cells late in infection, when a single transcript of about 2.5 kb appeared at 120 min postinfection. This result was confirmed by Western blotting with a specific anti-vChti-1 protein antibody; a protein of about 94 kDa was detected specifically beginning at 240 min postinfection and was present until cell lysis. The protein was not incorporated into viral particles but remained in the medium after cell lysis. The vChti-1 protein produced in virus-infected cells showed chitinase activity on zymogram assays.

Structural features in heparin that interact with VEGF165 and modulate its biological activity

The 165 amino acid form of vascular endothelial growth factor (VEGF165) is a heparin-binding growth factor with mitogenic activity for vascular endothelial cells. We examined activities of various heparin derivatives toward their interactions with VEGF165 using an enzyme-linked immunosorbent assay and elucidated the structural features in heparin for the interactions. Native heparin interacted with VEGF165, whereas N-desulfated, N-acetylated (N-DS, N-Ac-) heparin, and 6-O-desulfated (6-O-DS-) heparin did not. The 2-O-desulfated (2-O-DS-) heparin retained the ability for the interaction with VEGF165. In contrast, the 2-O-DS-heparin exhibited no ability for the interaction with FGF-2 and HGF. Thus, structural requirements in heparin for the specific interaction with VEGF165 are distinct from those with FGF-2 and HGF which require a high content of 2-O-sulfate groups. In a cell proliferation assay, native heparin and 2-O-DS-heparin exhibited inhibitory abilities for VEGF165-induced proliferation of human umbilical vein endothelial cells (HUVECs) with their high concentrations (more than 64 microg/ml), while only native heparin could enhance the proliferation of the chlorate-treated cells. These results suggested that a high content of 2-O-sulfate groups is not required for the specific interaction with VEGF165alone, although it is essential for the mitogenic activity of the growth factor.

[Composition of vascular tree using moving-table MR angiography: development and preliminary clinical experience with a semi-automated program combining stacks of MR angiographic images]

Moving-table MR angiography, combining a contrast enhanced MRA approach with table movement, has recently become available. This technique allows imaging of long, longitudinal anatomical regions of vasculature. We have developed a semi-automated program combining stacks of MRA images obtained from different image stations, and applied it to the reconstruction of vascular trees in twenty-five patients with peripheral arterial occlusive disease. Using this program, continuous vascular trees, extending from the abdominal aorta to lower leg (up to 124 cm), were semi-automatically reconstructed within two minutes from six different projection angles. Extensive vascular lesions were recognized three-dimensionally by moving image display mode.

Loss of interhemispheric connectivity in patients with lacunar infarction reflected by diffusion-weighted MR imaging and single-photon emission CT

BACKGROUND AND PURPOSE

Although decreased neuronal connectivity in white matter has been reported to be a key mechanism of vascular dementia, assessment of white matter changes by diffusion-weighted MR imaging in relation to measures of associative function has not been previously addressed. We evaluated the loss of interhemispheric neuronal connectivity in vascular dementia by measuring diffusional anisotropy of the corpus callosum and determining its relationship to the regional cortical activity as reflected by cortical perfusion.

METHODS

Nine patients with multiple lacunar infarction and six healthy volunteers (25-35 years old) were examined. We developed a method to determine the active cortical volume (ACV) by masking iodine-123 iodoamphetamine SPECT scans to eliminate the effect of brain atrophy. The anisotropic rate (AR) was calculated as a ratio of two perpendicular diffusion coefficients in diffusion-weighted MR imaging.

RESULTS

Compared with the ACVs of the healthy volunteers, there were significant decreases in the ACVs in the frontal associative areas in the patients, and these were significantly correlated with cognitive scores. The frontal ACVs showed good correlations with the AR of the anterior corpus callosum among all participants; however, only insignificant trends toward correlation were observed between these two parameters within the patient group.

CONCLUSION

A possible relationship between diffusional anisotropy of the anterior corpus callosum and frontal associative function was suggested; however, an estimation of the decrease in neuronal connectivity in patients with multiple lacunar infarction in terms of the deterioration in diffusional anisotropy requires further documentation.

Loss of transcription factor IRF-1 affects tumor susceptibility in mice carrying the Ha-ras transgene or nullizygosity for p53

The transcription factor IRF-1 has been implicated in tumor suppression: IRF-1 suppresses cell transformation and mediates apoptosis in vitro. Here we show that the loss of IRF-1 alleles per se has no effect on spontaneous tumor development in the mouse but dramatically exacerbates previous tumor predispositions caused by the c-Ha-ras transgene or by nullizygosity for p53. Grossly altered tumor spectrum, as compared to p53-null mice, was also observed in mice lacking both IRF-1 and p53, and cells from these mice show significantly higher mutation rate. Our results suggest that IRF-1 is a new member of the tumor susceptibility genes.

Interferon gamma increases the antitumor activity of mitomycin C against human colon cancer cells in vitro and in vivo

A combined antitumor activity of mitomycin C (MMC) and interferon gamma-1a (IFN-gamma) was evaluated to be synergistic by the 3-(4, 5-dimethylthiazol-2yl)-2,5-diphenyl-2H tetrazolium bromide assay and human tumor xenografts/severe combined immunodeficient (SCID) mouse system using colon cancer cell lines. The experimental metastasis of WiDr cells in SCID mouse was inhibited by MMC and IFN-gamma with their synergism. Intracellular uptake of MMC in WiDr cells in vitro was significantly increased by IFN-gamma, suggesting the mode of synergism of these agents. This model may also partly explain the antitumor activity of combined MMC, 5-fluorouracil and interleukin-2 treatment on hepatic metastasis of colon cancer.

Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies

BACKGROUND/PURPOSE

This report describes the results of a group study of the Japanese Study Group of Anorectal Anomolies (JSGA) to determine the relative incidence of specific types of anorectal anomaly in Japan, and includes discussion of rectourethral fistula regarding the relationship between the levels of the fistula and blind end of the rectum, low type deformity, rare types, and associated anomalies.

METHODS

A total of 1,992 patients (1,183 boys and 809 girls) registered from 1976 to 1995 were analyzed.

RESULTS

High-type deformities accounted for 26.0% of cases, intermediate 10.7%, low 57.2%, miscellaneous 4.5% and unclassified 1.8%. The most frequent deformity was male anocutaneous fistula (n = 364), followed by male rectourethral fistula (n = 333), and female anovestibular fistula (n = 241). There were 42 rectovesical fistulas in boys and 93 rectocloacal fistulas in girls. Covered anus complete occurred at the same frequency (10.1% of low deformities) as covered anal stenosis. In rectourethral fistula, the blind end of the rectum lay at or above the level of the P-C line in 40.3% of cases, at or above the M line in 39.6% and at the vicinity of the I line in 20.2%, respectively. There was no parallel relationship between the site of the fistula opening and the level of the rectal pouch. The overall incidence of patients having one or more associated anomalies was 45.2%: 70.6% in high deformity, 60.7% in intermediate, and 31.3% in low. The rate of association of Down's syndrome with deformities without fistula (40.3%) was significantly higher than with deformities with fistula (0.3%).

CONCLUSIONS

Rectovesical fistula and covered anus complete were not infrequent deformities in this series. We consider that at least 20% of rectourethral fistula should be categorized as intermediate or low deformity from the viewpoint of the position of the rectal pouch. A significant preponderance of Down's syndrome in the deformities without fistula suggests that further investigation of associated anomalies in comparision with other congenital diseases may provide insights into the pathogenesis of anorectal malformation in the field of molecular genetics.

Metallic artifacts of coronary and iliac arteries stents in MR angiography and contrast-enhanced CT

Metallic artifacts of intravascular stents were assessed with MR angiography and contrast-enhanced spiral CT. Stainless steel showed less metal artifact than tantalum stent in CT. Metallic artifact in coronary and iliac arteries treated with tantalum stent was not remarkable in MR angiography. Contrast-enhanced CT might be preferable to assess patency of arteries treated with stainless steel stent. while MR angiography was useful in depicting intraluminal signal in tantalum stent.

[Relationship between plasma hormones and ventricular premature contractions in extracorporeal shock wave lithotripsy--significance of human atrial natriuretic peptide (hANP)]

Extracorporeal shock wave lithotripsy (ESWL) is a safe and effective treatment for upper urinary tract stones. However, the mechanism by which this treatment may be involved in causing ventricular premature contractions (VPC) is unknown. We evaluated the relationship between VPC and plasma hormones in patients treated by ESWL. Holter monitoring was performed on 61 outpatients undergoing ESWL with electrocardiographic synchronization for upper urinary tract stones. The levels of cathecolamine, plasma renin activity (PRA), plasma aldosterone concentration (PAC), and human atrial natriuretic peptide (hANP) were measured before, immediately after, and 7 days after ESWL. Systolic blood pressure increased significantly immediately after, and decreased 7 days after ESWL. VPC occurred during 23 treatments (37.7%) but during ESWL no significant relationship was observed with the treatment side or location. Epinephrine increased significantly immediately after ESWL. hANP increased significantly immediately after ESWL, and decreased 7 days later. VPC occurred in all patients who had an hANP value above 40 pg/ml before ESWL. These results suggest that VPC is related to hemodynamic changes, and that hANP can predict VPC during ESWL.

Effects of various kinds of dietary amino acids on the hepatotoxic action of D-galactosamine in rats

The protective effects of various kinds of dietary amino acids against the hepatotoxic action of D-galactosamine (GalN) were examined. Male Wistar rats fed with 20% casein diets containing 10% or 5% amino acid for one week were injected with GalN (800 mg/kg body weight), and the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities, the hepatic glycogen concentration, and the serum glucose-level were examined 20 hours after the injection. In the groups with the 10% amino acid diets, activities of AST, ALT, and LDH in serum of 10% L-glutamine (Gln), 10% L-asparagine (Asn), and 10% L-serine (Ser) groups were significantly lower than those of the control group, and in the groups with the 5% amino acid diets, those activities of 5% L-histidine (His), 5% L-tyrosine (Tyr), 5% L-lysine (Lys), and 5% L-glycine (Gly) groups were also lower than those of the control group. The concentration of liver glycogen of 10% Gln-, 10% Asn-, and 10% Ser- groups and those levels of 5% His-, 5% Tyr-, 5% Lys-, and 5% Gly-groups were also significantly higher than that of the control group. As a result, it was found that some kinds of dietary amino acid such as L-Ser, L-Asn, L-His, L-Lys, L-Tyr, and L-Gly, in addition to L-Gln were effective to protect the rats from GalN-induced injury.

Effect of luminance contrast on the motion aftereffect

The effects of luminance contrast and spatial frequency on the motion aftereffect were investigated. The point of subjective equality for velocity was measured as an index of the motion aftereffect. The largest effect was observed when a low contrast grating (5%) was presented as a test stimulus after adaptation to a high contrast grating (100%) in the low spatial frequency condition (0.8 cycle deg.-1). On the whole, the effect increased with increasing adapting contrast and with decreasing test contrast or spatial frequency. Small effects were observed at high test contrasts. These results were inconsistent with those of Keck, Palella, and Pantle in 1976. Analysis showed that there was no saturation on velocity of the motion aftereffect above 5% of the contrast although Keck, et al. (1976) found that the incremental increases of the effect above 3% adapting contrast were small.

Crossed cerebellar diaschisis: the role of motor and premotor areas in functional connections

The authors assessed the relationship between crossed cerebellar diaschisis (CCD) and cortico-pontine cerebellar pathway (CPCP) damage in 29 chronic supratentorial infarct patients to elucidate the role of motor and premotor areas for functional cerebro-cerebellar connections. The CCD rate was calculated from side-to-side cerebellar count differences on 123I-IMP single-photon emission computerized tomography images. Neuronal damage was estimated by the three scores of computed tomography density from equal to normal brain tissue (score 0) to equal to cerebrospinal fluid (score 2) in the 4 major regions on CPCP; frontal association, motor and premotor, sensory and parietal associations, and the posterior limb of the internal capsule. Two-factor factorial ANOVA by the score and the region revealed significant differences of the CCD rate in the score factor (score 0 or 1 vs. score 2, p = < 0.05) and the independency of these two factors. Categories determined by the scores in each region were analyzed by multiple stepwise regression analysis using the theory of quantification I, in which significant correlation only between CCD and the necrotic density (score 2) in motor and premotor areas were demonstrated (r = 0.515, p = < 0.05). The authors conclude that neuronal loss in motor and premotor areas seem to contribute significantly to functional cerebro-cerebellar disconnections.

Combined antitumour activity of mitomycin C, 5-fluorouracil and interleukin-2 against human colon cancer cells

Combined treatment of interleukin-2 (IL-2), 5-fluorouracil (5-FU) and mitomycin C (MMC) is reported to be effective against hepatic metastasis of colon carcinoma. To clarify this modality, we investigated lymphokine activated killer (LAK) activity of human peripheral lymphocytes on colon cancer cell lines by 51Cr release assay. LAK activity against Colo 205 cells by untreated lymphocytes was 12%, which increased to 25% upon the addition of 5-FU, but remained unchanged upon the addition of MMC. The combined antitumour activity of MMC or 5-FU with or without LAK-supernatant was evaluated by MTT assay; antitumour activity of MMC was increased by the addition of LAK-supernatant. The concentration of interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) was increased in LAK-supernatant, and the antitumour activity of combined IFN-gamma and MMC was synergistic. The mechanism of this therapy seemed to be associated with both increased LAK activity by 5-FU and increased antitumour activity of MMC with IFN-gamma.

[Ocular tuberculosis]

The frequency of tuberculous uveitis has extremely decreased in Japan. Anterior granulomatous or non-granulomatous uveitis, chorioretinitis and retinal vasculitis are common ocular manifestations, while tuberculoma, scleritis, keratitis and orbital tuberculosis are rare. The diagnosis of ocular tuberculosis is extremely difficult because ocular tuberculosis tends to be negative in chest x-ray or tuberclin skin test. To diagnose ocular tuberculosis clinically some ophthalmologists recommend subconjunctival tuberculin test or therapeutic isoniazide (INH) test. Recently, for confirmed diagnosis, polymerase chain reaction (PCR) technique has been used to detect mycobacterium in intraocular samples such as aqueous or vitreous humor. The mainstay of treatment is antituberculosis agents. Active retinal vasculitis or tuberculoma are generally responsive to corticosteroid therapy. Although ocular tuberculosis is rare, it must be considered as one of the possible causes of uveitis.

Anti-ulcer effects of antioxidants, quercetin, alpha-tocopherol, nifedipine and tetracycline in rats

When free radical-scavenging activities of quercetin, alpha-tocopherol, nifedipine and tetracycline were measured by an electron spin resonance technique, all test compounds (10(-5) to 10(-3) M) scavenged both superoxide anions and hydroxyl radicals. The oral administration of quercetin (50 and 100 mg/kg), alpha-tocopherol (8 and 16 mg/kg), nifedipine (20 and 40 mg/kg) or tetracycline (10 and 20 mg/kg) markedly prevented the HCl plus ethanol-induced gastric mucosal injury and the increase in the content of thiobarbituric acid-reactive substances in the injured mucosa in rats. In addition, quercetin (25, 50 and 100 mg/kg), alpha-tocopherol (4, 8 and 16 mg/kg), nifedipine (10, 20 and 40 mg/kg) and tetracycline (5, 10 and 20 mg/kg), given orally, twice daily for 14 consecutive days from the day after acetic acid injection, dose-dependently promoted the ulcer healing and inhibited the increase in the content of thiobarbituric acid-reactive substances in the ulcerated mucosa. These results indicate that quercetin, alpha-tocopherol, nifedipine and tetracycline possess gastric cytoprotective and gastric ulcer healing-promoting actions. In addition, the free radical-scavenging properties of these compounds may be partly related to their anti-ulcer effects.

Induction of apoptosis by cooperative action of vitamins C and E

Millimolar concentrations of sodium ascorbate (vitamin C) induced apoptotic cell death in human promyelocytic leukemic HL-60 cells. The apoptotic cells displayed a smaller cell volume, disappearance of cell surface microvilli, appearance of cytoplasmic vacuoles, chromatin condensation, nuclear fragmentation and production of apoptotic bodies. The apoptosis-inducing activity of sodium ascorbate was significantly enhanced by noncytotoxic concentrations of CuCl2, but was almost completely eliminated by FeCl3. CuCl2 transiently stimulated the hydrogen peroxide (H2O2) production by sodium ascorbate, whereas FeCl3 slightly reduced the H2O2 production. alpha-Tocopherol (vitamin E) slightly enhanced the radical and H2O2 productions, and apoptosis induction by sodium ascorbate. The effect of alpha-tocopherol seems to be rather specific for ascorbic acid, since alpha-tocopherol did not significantly affect the cytotoxic activity of CuCl2, FeCl3 nor gallic acid. The present study demonstrated the cooperative action of vitamins C and E.

The discrepancy between 99Tcm-ECD dynamic and static SPET images in patients with ischaemic lesions corresponds to reduced vasoreactivity to acetazolamide

We evaluated 99Tcm-N,N'-(1,2-ethylenediyl)bis-L-cysteine diethyl ester (99Tcm-ECD) dynamic and static SPET (single photon emission tomographic) images to examine 99Tcm-ECD kinetics under ischaemic cerebrovascular conditions. In 20 patients who showed arterial occlusion on magnetic resonance angiography, dynamic (0-10 min) and static (15-35 min) SPET images were acquired after the intravenous administration of 99Tcm-ECD. Thirteen of the patients had focal perfusion deficits that were more evident on the dynamic than on the static images; the other seven showed no such discrepancy. In those patients with a mismatch between the dynamic and static images, the extent corresponded to reduced vaso-reactivity to acetazolamide. Based on quantitative analysis of the ratio of tracer uptake in affected to that in unaffected areas, the patients with discrepant findings showed significantly different ratios on the dynamic and static images, whereas those with no such mismatch did not. Our results suggest that dynamic 99Tcm-ECD images provide circulatory information and that static images reflect a filling-in phenomenon of ECD metabolites in ischaemic lesions. 99Tcm-ECD dynamic and static SPET images offer an alternative method of detecting mild perfusion deficits without the need for acetazolamide challenge.

Reduced serum dehydroepiandrosterone levels in diabetic patients with hyperinsulinaemia

OBJECTIVE

To elucidate the interaction between insulin and dehydroepi-androsterone (DHEA) concentrations, we evaluated serum DHEA and DHEA-sulphate (DHEA-S) levels in diabetic patients with hyperinsulinaemia.

PATIENTS AND DESIGN

Twenty-four subjects with non-insulin dependent diabetes mellitus, 12 hyperinsulinaemic subjects (fasting serum insulin concentrations > or = 10 mU/ml (71.8 pmol/l)) and 12 non-hyperinsulinaemic subjects, and 10 normal control subjects were studied. Serum DHEA, DHEA-S, cortisol and ACTH levels were investigated in these subjects. Moreover, their serum DHEA levels were compared during hyperinsulinaemic-euglycaemic clamp and after ACTH stimulation.

MEASUREMENTS

Serum insulin, cortisol, ACTH, DHEA and DHEA-S concentrations were evaluated by RIA. Serum glucose was determined by the glucose oxidase method.

RESULTS

Diabetic patients with hyperinsulinaemia showed significantly lower levels of serum DHEA and DHEA-S than controls. After ACTH stimulation, these patients also showed significantly lower DHEA levels. During the hyperinsulinaemic-euglycaemic clamp, serum DHEA concentrations of diabetic patients with hyperinsulinaemia remained low and did not decline further, although those of control subjects and non-hyperinsulinaemic diabetic patients showed a significant decline of serum DHEA levels. Even after ACTH stimulation during the clamp, serum DHEA in hyperinsulinaemic patients was still significantly lower than in controls.

CONCLUSIONS

In diabetic patients with hyperinsulinaemia, baseline DHEA levels are chronically and maximally suppressed compared to control subjects and non-hyperinsulinaemic diabetic patients, and thus not decreased further by exogenous insulin infusion during hyperinsulinaemic-euglycaemic clamp.

Anti-ulcer effects of antioxidants: effect of probucol

We investigated the effect of probucol, a lipid-lowering agent with antioxidant properties, on HCl plus ethanol-induced gastric mucosal injury and on the healing of acetic acid-induced gastric ulcers in rats. When the free radical-scavenging activity of probucol was measured by an electron spin resonance technique, the agent (10(-5)-10(-3) M) scavenged both superoxide anions and hydroxyl radicals. Oral administration of probucol (250-1000 mg/kg) dose dependently prevented the HCl plus ethanol-induced gastric mucosal injury and the increase in thiobarbituric acid-reactive substances, an index of lipid peroxidation, in the injured mucosa. Repeated oral administration of probucol (250-1000 mg/kg twice daily) dose dependently accelerated the healing of acetic acid-induced gastric ulcers. In addition, probucol already inhibited the increase in the content of thiobarbituric acid-reactive substances in the ulcerated region before the ulcer-healing effect of this agent was recognized. These results suggest that probucol may partly protect gastric mucosa from acute gastric mucosal injury and promote the healing of chronic gastric ulcers by its antioxidant activity.