Osamu Uyama

Quantitative evaluation of vascular permeability in the gerbil brain after transient ischemia using Evans blue fluorescence.

Mongolian gerbils were used to evaluate brain edema during restoration of flow following bilateral carotid occlusion for 1 h. We have modified the method for fluorometric measurement of Evans blue to monitor vascular protein leakage (vasogenic edema). The extraction of extravasated Evans blue was performed by homogenizing the whole brain in 50% trichloroacetic acid. The supernatant was diluted fourfold with ethanol and the Evans blue fluorescence was measured. The tissue blank was negligible. Evans blue content of the plasma was similarly determined and the ratio of tissue to plasma Evans blue content was calculated. Furthermore, Evans blue fluorescence was used for microscopic investigation. It is suggested that Evans blue fluorescence can be applied for quantification of protein leakage with much more sensitivity and accuracy than the colorimetric absorbance method, as well as for tissue localization of protein leakage.

Protective effects of human recombinant superoxide dismutase on transient ischemic injury of CA1 neurons in gerbils.

Background and Purpose It has been postulated that oxygen-derived free radicals are produced in significant quantities upon reperfusion of ischemic brain and that the free radicals play a pivotal role in triggering the ischemic neuronal damage causing delayed neuronal death. This study was undertaken to examine the effects of human recombinant superoxide dismutase on the delayed neuronal death of CA1 neurons and on the change in the expression of messenger ribonucleic acid for endogenous copper-zinc superoxide dismutase after transient ischemia. Methods Human recombinant superoxide dismutase (8×105 units/kg) or apo-superoxide dismutase was administered intravenously 1 minute before bilateral carotid artery occlusion in gerbils divided among four experimental groups. Endogenous copper-zinc superoxide dismutase messenger ribonucleic acid was analyzed by in situ hybridization histochemistry using a sulfur-35-labeled oligonucleotide probe. Immunohistochemical localizations of administered human recombinant superoxide dismutase were investigated. Results All gerbils receiving apo-superoxide dismutase exhibited almost complete destruction of CA1 neurons 7 days after 5 minutes of ischemia. The gerbils treated with human recombinant superoxide dismutase showed mild lesions (p<0.01). Discrete localizations were observed for endogenous copper-zinc superoxide dismutase messenger ribonucleic add. Transient ischemia increased labeling throughout the hippocampus after 30 minutes and 24 hours of reperfusion. This increase was abolished by treatment with human recombinant superoxide dismutase. This phenomenon was confirmed by Northern blot analysis. The interneurons in CA3 and cells in the hilus were mainly stained against administered superoxide dismutase at 5 and 30 minutes, and these reactions had disappeared at 20 hours after the administration. Conclusions Our data demonstrate protective effects of human recombinant superoxide dismutase against ischemic neuronal damage and support the hypothesis that the generated free radicals induce a vicious cycle leading to delayed neuronal death.

Do anger and aggression affect carotid atherosclerosis

Background and Purpose Although a number of metabolic and psychosocial factors have been identified as coronary risk factors, no studies have evaluated the relation between personality and cerebrovascular disease. The purpose of the present study was to elucidate the relation between the characteristics of anger or aggression and the severity of carotid atherosclerosis on the basis of the findings of B-mode ultrasonography. Methods The Cornell Medical Index was used to measure anger in 34 patients with signs of atherosclerosis or at least one of four recognized risk factors for atherosclerosis (hypertension, hypercholesterolemia, diabetes mellitus, and cigarette smoking). The Rosenzweig Picture Frustration Study and Yatabe-Guilford Personality Test were used to evaluate aggression. High-resolution B-mode ultrasonography was performed, and the severity of carotid atherosclerosis was determined by plaque score. The occurrence of risk factors for carotid atherosclerosis was compared among the patients. Results The correlation of plaque score with one item that endorses anger was r=.65 (P<.01) and with “extrapersistive” in aggression was r=.50 (P<.01). Multivariate analysis identified significant correlations between plaque score and age, hypercholesterolemia, and anger. Conclusions Our results suggest that anger and, perhaps, aggression may be risk factors for cerebrovascular disease.

Protective effects of superoxide dismutase on acute reperfusion injury of gerbil brain.

It has been postulated that oxygen-derived free radicals are produced in significant quantities upon reperfusion of ischemic brain and could cause brain edema and cell death. This study was undertaken in an attempt to examine the effect of recombinant human superoxide dismutase, a scavenger of superoxide radicals, on survival outcome and brain edema in gerbils undergoing 1-hour bilateral carotid occlusion and reperfusion. Superoxide dismutase was continuously infused over either 1 or 3 h of reperfusion. Neither low dose (100,000 U/kg bolus followed by 100,000 U/kg/h continuous infusion) nor high dose (100,000 U/kg bolus followed by 800,000 U/kg/h) recombinant human superoxide dismutase had an effect upon water and sodium content of whole brain at 1 h of reperfusion following 1 h of ischemia, but high-dose treatment effectively reduced brain water content at 3 h of reperfusion. All gerbils receiving high-dose treatment survived the 3 h of reperfusion, while 4 of the 7 gerbils in the control group died between 2 and 3 h of reperfusion (p less than 0.05). From this study, we conclude that prophylactic administration of superoxide dismutase can reduce the delayed vasogenic edema developing at 3 h of reperfusion and afford significant cerebroprotection in these models of transient global ischemia.

Prostate Cancer-Induced Oncogenic Hypophosphatemic Osteomalacia

A 65-year-old male with prostate carcinoma showed mild hypocalcemia of 7.9 mg/dl, marked hypophosphatemia of 1.7 mg/dl, hyperphosphaturia (tubular reabsorption of phosphorus 43% and tubular threshold for phosphorus of 0.6 mg/dl), low serum 1,25 (OH)2D level of less than 5 pg/ml and osteomalacia indicated by a marked increase of relative osteoid volume and fractional formation rate in the undecalcified section. Oncogenic osteomalacia due to prostatic carcinoma with suppression of 1,25 (OH)2D production and phosphaturia was suggested.

Niceritrol reduces plasma lipoprotein(a) levels in patients undergoing maintenance hemodialysis

Lp(a) is an LDL-like lipoprotein carrying the apoprotein(a) glycoprotein and has recently been recognized to be an independent risk factor for coronary heart disease. We studied plasma Lp(a) levels in 40 patients undergoing maintenance hemodialysis (24 male, 16 female; aged 16-83 years). Fasting plasma Lp(a) levels were measured by an enzyme-linked immunosorbent assay. The median value of plasma Lp(a) concentrations in hemodialysis patients was significantly higher than that of the normal volunteers (26.0 +/- 2.7 vs. 10.8 +/- 3.7 mg/dL, p < .05). Lp(a) levels did not correlate with age, duration of hemodialysis, total cholesterol, triglyceride, HDL cholesterol, or LDL cholesterol. The 11 patients whose plasma Lp(a) concentrations exceeded 20 mg/dL received niceritrol, a prodrug of nicotinic acid, at a dosage of 500 mg t.i.d. for 4 weeks. The plasma Lp(a) levels were significantly lower after 4 weeks of treatment (38.3 +/- 4.2 vs. 31.5 +/- 3.2 mg/dL, p < .01).

Decreased Sodium Dependent D-Glucose Transport Across Renal Brush-Border Membranes in cis-Diamminedichloride Platinum Induced Acute Renal Failure

Na-coupled D-glucose transport in rabbits with cis-diamminedichloride platinum (CDDP; cisplatin) induced acute renal failure (ARF) has been studied. ARF occurred at 3 days after injection of CDDP (3 mg/kg i.v.). Na-coupled D-glucose transport into brush-border membrane vesicles (BBMV) from both outer cortex (OC) and outer medulla (OM) of ARF rabbits under zero-trans condition was decreased. Increased Km (i.e., decreased affinity of transport carrier for D-glucose) in OC and decreased Vmax (i.e., decreased number of glucose carrier) in OM were observed in CDDP-induced ARF rabbits. Decrease glucose transport was also observed under equilibrium exchange condition. Intravesicular volume of BBMV from OC and OM of ARF rabbits was decreased. In homogenate and BBMV from OC and OM of ARF rabbits, activities of gamma-glutamyl transpeptidase and alkaline phosphatase (marker enzymes of brush-border membrane) were decreased. Activities of succinate dehydrogenase, glucose-6-phosphatase, and Na-K ATPase (marker enzymes of mitochondria, endoplasmic reticulum, and basal lateral membrane, respectively) were not affected by CDDP administration. These results suggested that one of the main target sites of CDDP in kidney is brush-border membrane (BBM) along the proximal tubule, that is, not only Na-coupled D-glucose transport carrier protein but also other proteins in BBM.

Effects of hydrocortisone and aminophylline on plasma leukotriene C4 levels in patients during an asthmatic attack

To study the role of leukotriene C4(LTC4) and the effect of hydrocortisone and aminophylline on plasma LTC4 levels in patients with asthmatic attacks, we measured LTC4 in plasma of 18 asthmatics during a wheezing attack and of 7 normal subjects. Blood samples were obtained before and after treatment with aminophylline and/or hydrocortisone injections. We extracted LTC4 using a Sep-Pak C18 cartridge for the measurement of LTC4 by radioimmunoassay. The plasma levels of immunoreactive LTC4 (i-LTC4) of the normal subjects were 142 +/- 25 pg/ml (n = 7), while those of nonatopic type asthmatic patients with wheezing attacks were 208 +/- 68 pg/ml (n = 15) (p less than 0.01). Before and after treatment with both hydrocortisone succinate (100 mg) and aminophylline (250 mg), 6 asthmatic patients with wheezing attacks had a mean plasma level of i-LTC4 181 +/- 24 and 132 +/- 18 pg/ml (p less than 0.01), respectively. On the other hand, the treatment with aminophylline 250 mg alone increased the i-LTC4 levels from 178 +/- 19 pg/mg to 213 +/- 16 pg/mg (n = 6)(p less than 0.05), while treatment with hydrocortisone succinate 100 mg decreased the i-LTC4 level 0.05 from 284 +/- 99 pg/ml to 249 +/- 85 pg/ml (n = 4)(p less than 0.05). In conclusion, the present study shows that the i-LTC4 level in venous blood of patients with asthmatic attacks is decreased significantly by treatment with hydrocortisone succinate.

Sustained Metabolic Alkalosis Associated with Development of the Milk-Alkali Syndrome

Takeshi Nakanishi, MD, 5th Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663 (Japan) Dear Sir, The milk-alkali syndrome (MAS) has been described as hypercalcemia and metabolic alkalosis from the treatment for peptic ulcer with a high calcium and absorbable alkali intake in any form, usually as calcium carbonate. After the introduction of H2 Mockers has altered the basis of treatment of peptic ulcer, MAS may still occur with the ingestion of a smaller amount of calcium and alkali [1-3]. The pathogenesis of MAS has not been fully understood. The evidence below suggests that the sustained alkalosis might be related to MAS. (a) Patients with accelerated acid excretion or suppressed alkali excretion, i.e., duodenal ulcer or renal complication, are more inclined to develop MAS and to a much greater degree [4]. (b) Increased tubular reab-sorption of calcium is maintained in chronic metabolic alkalosis [5, 6]. We saw a patient with MAS suggesting that only sustained metabolic alkalosis could develop MAS. This 74-year-old man had a history of cerebral infarction (middle cerebral artery region), and improved activity during the course of rehabilitation. The patient had been prescribed magnesium oxide (2 g/day = 35.5 mEq alkali) for chronic constipation and ingested milk (200 ml = 0.22 g calcium) and ice cream (145 g = 0.19 g calcium) every day for 4 months. He had several episodes of aspiration pneumonia and elevated body temperature and was treated with minocyc-line and ofloxacine. When the patient began to feel severe nausea and anorexia, hypercalcemia (serum Ca 14.3 mg/dl), hypernatremia (serum Na 161 mEq/1), metabolic alkalosis (HCOi 37.4 mEq/1), and renal insufficiency (serum creatinine 2.34 mg/dl) were observed. A predisposition to hypercalcemia could not be shown by any known factors. On cessation of therapy and correction of dehydration, the serum Ca rapidly returned to normal within 1 week. TRP on diagnosing this disorder was 50.5%, which suggested hyperparathyroid-ism, and returned to a 90% normal range when serum Ca was restored to its normal range. Although the present case showed triads of MAS, hypercalcemia, metabolic alkalosis, and renal insufficiency, it could be distinguished from any other case previously reported with regard to the small amount of calcium (0.4 g/day) and alkali (35.5 mEq/ day) intake and the two clinical situations outlined below. The patient did not have the complication of peptic

Amino acids as well as polyols and methylamines accumulated in rat kidney during dehydration.

SummaryDuring antidiuresis cells in the renal inner medulla contain large amounts of sorbitol, myo-inositol, glycerophosphorylcholine and betaine to adjust the intracellular osmolality to the extracellular hyperosmolality. Although the accumulation of these four major organic osmolytes in the inner medulla of the dehydrated animal has been a consistent finding, the role of another class of organic osmolytes, amino acids, in osmoregulation in the kidney remains controversial. In the present study, renal responses of four major osmolytes and amino acids to dehydration were investigated using two HPLC systems. Taurine levels were significantly higher in the inner medulla of the dehydrated rats as compared with the control rats, and increased monotonically from the cortex to the inner medulla along the corticopapillary axis in the dehydrated rats. As for four major osmolytes, we confirm previously reported patterns in antidiuresis in greater detail. In conclusion, not only the four major osmolytes but taurine also plays a salient role in the osmoregulation in the kidney.