Adrenergic receptor-mediated Cl- transport in rabbit corneal endothelial cells

Adrenoceptor-mediated Cl- transport in cultured rabbit corneal endothelium was examined using a Cl(-)-sensitive fluorescent dye. The intracellular Cl- concentration ([Cl-]i) in the endothelial cells was estimated to be about 30 mM. Noradrenaline (0.001-0.1 mM) transiently decreased the [Cl-]i in a dose-dependent manner. Such a decrease in [Cl-]i was completely antagonized by pretreatment with the alpha-adrenoceptor antagonist phentolamine (0.1 mM). The selective alpha 2-adrenoceptor agonist UK 14304-18 (5-bromo-6-[(4H,5H-imidazol-2-yl)amino]quinoxaline, 0.1 mM) persistently decreased the [Cl-]i, but neither the alpha 1-adrenoceptor agonist phenylephrine (0.1 mM) nor the beta-adrenoceptor agonist isoproterenol (0.1 mM) had any effect. The alpha 2-adrenoceptor agonist/antagonist yohimbine (0.1 mM) persistently and more strongly decreased the [Cl-]i than UK 14304-18 did. The yohimbine-induced decrease in the [Cl-]i was not further altered by UK 14304-18 or phenylephrine, but partly reversed by noradrenaline, isoproterenol and an adenylate cyclase activator, forskolin (0.1 mM). The yohimbine-induced decrease in [Cl-]i was inhibited by the carbonic anhydrase inhibitor acetazolamide (1 mM), and Cl-/HCO3- exchange inhibitors, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, but not by the H(+)-ATPase inhibitor N,N'-dicylohexylcarbodiimide. The forskolin-induced recovery in [Cl-]i was inhibited by the Na+/K+/Cl- cotransport inhibitor bumetanide (0.1 mM), but not by the Cl- channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of the time to peak hepatic enhancement to optimize contrast-enhanced spiral CT

A technique for the prediction of the time to peak hepatic enhancement to optimize contrast-enhanced spiral CT has been developed. The procedures are (a) to inject a small amount of contrast medium rapidly via the antecubital vein and measure aortic transit time (ATT) of the bolus by single slice dynamic CT; (b) to inject contrast medium at a high rate, expecting peak hepatic enhancement to occur at ATT plus 8 seconds after the end of injection; (c) to perform spiral scanning of the liver using thin collimation and caudo-cranial table movement beginning at ATT after the end of contrast medium injection.

Postsurgical intrahepatic portal thromboembolism: a possible cause of perfusion defects on CT during arterial portography

OBJECTIVE

Our goal was to investigate unexplained nontumorous perfusion defects on CT arterial portography (CTAP).

MATERIALS AND METHODS

The CTAP images of 35 patients who underwent partial hepatectomy or open biopsy were analyzed. Hepatic tumors consisted of hepatocellular carcinoma (n = 18) and colorectal carcinoma metastases (n = 17). Nontumorous perfusion defects were categorized into those previously explained and those unexplained. We investigated unexplained ones and their relationship with the underlying conditions.

RESULTS

Eight unexplained nontumorous perfusion defects were found in four patients with colorectal metastases. Statistical analysis showed that the defects occurred with significantly higher incidence in patients with colorectal metastases than in those with hepatocellular carcinoma (p = 0.046, Fisher test). All four patients with defects underwent CTAP within 1 month after colorectal surgery. A significant difference was seen in the distribution of surgery-CTAP time intervals between those patients with and those without defects (p < 0.05, Wilcoxon-Mann-Whitney test). Intrahepatic portal thrombi were pathologically proven in one of the four patients.

CONCLUSION

Unexplained nontumorous hepatic perfusion defects may represent postsurgical portal thromboemboli.

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations in elderly men and women

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations were examined in 30 elderly men and women. These subjects were randomly divided into two groups. The training group [n = 15; 7 men and 8 women; mean age 75.5 (SD 5.6) years] agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate concentration threshold for 30 min 3-6 times a week for 9 months. The other group [n = 15; 7 men and 8 women; mean age 73.7 (SD 4.4) years] did not perform any particular physical training and was followed as the control. Following this training period the high density lipoprotein-cholesterol (HDL-C) had increased significantly (P < 0.01) while the total cholesterol (TC):HDL-C ratio had decreased significantly (P < 0.01) in the training group after 9 months but had not changed in the control group. The TC, triglyceride (TG) and low density lipoprotein-cholesterol (LDL-C) had not changed significantly in either group. No significant difference was seen between the groups throughout the period for TC. LDL-C or TG. There was, however, a significant correlation between the initial TC:HDL-C ratio and the change in the TC:HDL-C ratio following 3 months of training (P < 0.05). After 1 month of detraining in 5 patients, the HDL-C had decreased significantly (P < 0.05) while the TC:HDL-C had increased significantly in the training group (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Modification of rectal absorption of morphine from hollow-type suppositories with a combination of alpha-cyclodextrin and viscosity-enhancing polysaccharide

An attempt was made to optimize the rectal delivery of morphine, using cyclodextrins as an absorption enhancer and polysaccharides as a swelling hydrogel in Witepsol H-15 hollow-type suppositories, and this was tested in rabbits. alpha- and beta-cyclodextrins enhanced the rate and extent of bioavailability, the former being more effective; gamma-cyclodextrin decreased the absorption of morphine. The in-vitro membrane permeation studies using excised rectal sacs revealed that alpha-cyclodextrin enhanced the permeation of morphine through the rectal membranes. In contrast, viscous polysaccharides such as xanthan gum retarded the plasma morphine levels after the rectal administration, reflecting in-vitro slow release characteristics. A combination of alpha-cyclodextrin and xanthan gum produced sustained plasma profiles of morphine along with an increased rectal bioavailability (more than 4 times). From the observation of the distribution behavior of suppositories in rabbit rectum and colon after the rectal administration, xanthan gum was found to prevent the upward spread of the drug. Gross and microscopic observations suggested that this preparation was less irritating to the rectal mucosa.

Differential effects of sulfate and sulfobutyl ether of beta-cyclodextrin on erythrocyte membranes in vitro

The hemolytic activity of beta-cyclodextrin (beta-CyD) on rabbit erythrocytes was reduced by the introduction of negatively-charged groups onto the hydroxyls of beta-CyD; the membrane disrupting abilities decreased in the order of beta-CyD > 2-hydroxypropyl-beta-CyD (HP-beta-CyD) > sulfobutyl-beta-CyD (SB-beta-CyD) >> beta-CyD sulfate (S-beta-CyD). Under pre-hemolytic concentrations, both beta-CyD and SB-beta-CyD induced shape changes of membrane invagination on the erythrocytes. In sharp contrast, S-beta-CyD showed biphasic effect on the shape of the erythrocytes; i.e. the crenation at relatively low concentrations and the invagination at higher concentrations. The S-beta-CyD-induced membrane crenation arose from a direct action on the membranes rather than cell metabolism-mediated effects. Unlike beta-CyD, S-beta-CyD was found to bind to the erythrocytes and may be confined to the outer surface of the membrane bilayer, which may expand the exterior layer relative to the cytoplasmic half, thereby inducing the cells to crenate. On the other hand, the membrane invagination mediated by the three beta-CyDs was initiated by extracting specific membrane lipids from the cells, depending upon their inclusion abilities, subsequently leading to the lysis of the cells. These results indicate that SB-beta-CyD and S-beta-CyD interact with the erythrocyte membranes in a differential manner and possess lower membrane disrupting abilities than the parent beta-CyD and HP-beta-CyD.

In vivo measurement of acetylcholinesterase activity in the brain with a radioactive acetylcholine analog

A novel method for visualization of brain acetylcholinesterase (AChE) in vivo has been developed. Following intravenous administration of a radiolabelled acetylcholine analog, N-methyl-3-piperidyl acetate, there was very good agreement between the distribution of radioactivity and AChE activity in the brain of rat and monkey. The method would be applicable for in vivo studies of human brain AChE activity in disorders of central cholinergic systems such as Alzheimer's disease.

Characterization of the inclusion mode of beta-cyclodextrin sulfate and its effect on the chlorpromazine-induced hemolysis of rabbit erythrocytes

The inclusion mode of beta-cyclodextrin sulfate (beta-CyD-sul) with a cationic drug, chlorpromazine, was investigated, and the effect of beta-CyD-sul on the hemolytic activity of chlorpromazine was compared with that of parent beta-CyD. The interaction of beta-CyD-sul with chlorpromazine was weaker than that of parent beta-CyD, probably because of the steric or electrostatic repulsion between anionic sulfate groups and hydrophobic phenothiazine moiety. Spectroscopic studies, including pH- and salt-effects, as well as thermodynamic parameters, suggested that both electrostatic and hydrophobic interactions are operative in the inclusion complexation of beta-CyD-sul with chlorpromazine. The inhibiting effect of parent beta-CyD on the chlorpromazine-induced hemolysis of rabbit erythrocytes was accounted for by the decreased fraction of free drug through the complexation. In the case of beta-CyD-sul, the hemolysis and binding of the drug to the erythrocyte membrane was higher than those estimated from the fraction of free drug, probably due to the increased hydrophobicity of the drug through the complexation. However, the chlorpromazine-induced shape change of the erythrocytes was significantly suppressed by beta-CyD-sul, and its inhibiting effect was greater than that of beta-CyD, because of the counterbalance of the opposite effects, i.e., internalization and externalization induced by chlorpromazine and beta-CyD-sul, respectively.

[Ultrasonography in primary malignant lymphoma of the thyroid]

We analyzed retrospectively the sonographic appearance of eight cases of primary malignant lymphoma of the thyroid. Sonography showed hypoechoic masses replacing thyroid parenchyma with posterior acoustic enhancement. A hypoechoic and/or nearly anechoic confluent nodular appearance characterized malignant lymphoma of the thyroid.

Monoclonal antibodies recognizing 2-oxo acid dehydrogenase components in granular structures in neurons

Monoclonal antibodies (MAbs) were raised against the hippocampal homogenate of young rats and classified into three types by immunohistochemical analysis: (1) MAbs specific for a granular structure observed within neurons, (2) MAbs specific for neuronal cell surface and cell body, and (3) MAbs specific for both neurons and astroglial cells. One MAb (2D11-7) specifically reacted with granular structures observed in neurons. A specific protein antigen was purified from rat homogenate by immunoadsorbent assay with MAb 2D11-7. Amino acid sequencing followed by lysyl endopeptidase digestion of the proteins in the eluate demonstrated that the antigens recognized by MAb 2D11-7 were E2 components of the 2-oxoglutarate dehydrogenase complex and pyruvate dehydrogenase complex. The cell specificity and age dependency of these proteins are also discussed.

Design and evaluation of radioactive acetylcholine analogs for mapping brain acetylcholinesterase (AchE) in vivo

For mapping brain acetylcholinesterase (AchE) in vivo, seven radioactive acetylcholine analogs, N-[14C]methylpiperidyl-3- and 4-acetates, propionates, isobutyrates, and 3-butyrate were newly synthesized and evaluated in mice. The esters readily entered the brain and were hydrolyzed into the hydrophilic metabolite, which was trapped. In brain homogenates, the esters showed a wide range of enzymatic reactivity (about 40-fold), and high specificity for AchE (more than 82%) except the butyrate. Intra-brain distribution of the esters reflected a pattern of AchE activity.

Partial splenic embolization with Y-shaped silicone particles

We have developed an embolizing material consisting of Y-shaped silicone particles for partial splenic embolization. Wide spaces for blood flow are left around the particles when these are lodged in arterial branches. We embolized one kidney in each of 3 dogs with the particles and observed a slowly induced occlusion of renal arterial branches during one month. The particles were also used for partial splenic embolization in 14 patients. The average portion of infarcted spleen tissue 7 days after embolization was 51% calculated from CT images. In 6 patients who had CT both 2 and 7 days after embolization, the average rate of splenic infarction increased from 29% at 2 days to 60% at 7 days. Our patients required analgesics for only 2.3 days on average. The Y-shaped silicone particles by slowly occluding splenic arterial branches produce ischemia in a gradual fashion which may minimize the pain after embolization.

Cystic islet cell tumors: radiologic findings in three cases

We report three cases of cystic islet cell tumors, two caused by gastrinomas and the other by an islet cell carcinoma. All three patients underwent computed tomography (CT) and angiography and two also had magnetic resonance (MR) imaging. Several common radiographic findings were present as follows: thickening of the cyst wall and irregularity of the inner surface on postcontrast CT and MR images, neovascularity and a densely staining hypervascular rim on angiography, and moderately increased signal intensity of the cyst content on T1-weighted MR images, which indicated fluid containing blood and/or necrotic tissue. These findings are helpful in defining the nature of these lesions and strongly suggest that cystic islet cell tumor should be included in the differential diagnosis.

A simple method for measuring glucose utilization of insulin-sensitive tissues by using the brain as a reference

A simple method, without measurement of the plasma input function, to obtain semiquantitative values of glucose utilization in tissues other than the brain with radioactive deoxyglucose is reported. The brain, in which glucose utilization is essentially insensitive to plasma glucose and insulin concentrations, was used as an internal reference. The effects of graded doses of oral glucose loading (0.5, 1 and 2 mg/g body weight) on insulin-sensitive tissues (heart, muscle and fat tissue) were studied in the rat. By using the brain-reference method, dose-dependent increases in glucose utilization were clearly shown in all the insulin-sensitive tissues examined. The method seems to be of value for measurement of glucose utilization using radioactive deoxyglucose and positron emission tomography in the heart or other insulin-sensitive tissues, especially during glucose loading.

A one-stage method for obtaining CT during arterial portography and hepatic arteriography

We describe a new technique for performing CT during arterial portography (CTAP) and during hepatic arteriography (CTHA) in a one-stage procedure, using a coaxial balloon catheter system and slip-ring CT equipment. This technique was employed in 10 patients with liver neoplasms. Both CTAP and CTHA images were obtained in all patients.

Aluminium beta-cyclodextrin sulphate as a stabilizer and sustained-release carrier for basic fibroblast growth factor

The water-insoluble aluminium salt of beta-cyclodextrin sulphate (Al.beta-CyD-Sul) was used as a stabilizer and sustained-release carrier for recombinant human basic fibroblast growth factor (bFGF). An adsorbate of bFGF with Al.beta-CyD-Sul was prepared by incubating the protein with a suspension of Al.beta-CyD-Sul in water. The mitogenic activity of bFGF released from the adsorbate, as indicated by the proliferation of kidney cells of baby hamster (BHK-21), was almost comparable with that of the intact bFGF. Al.beta-CyD-Sul significantly protected bFGF from proteolytic degradation by pepsin and alpha-chymotrypsin, compared with the water-soluble sodium salt. The in-vitro release of bFGF from the adsorbate was sustained in proportion to a rise in the ratio of Al.beta-CyD-Sul to the protein in the adsorbate. Of the bFGF preparations evaluated, the adsorbate of bFGF with Al.beta-CyD-Sul, when given subcutaneously to the rat, showed the most prominent increase in the formation of granulation tissues, due to the stabilization and slow-release of the mitogen. The limited data presented here suggest that the adsorbate of bFGF with Al.beta-CyD-Sul has a potent therapeutic efficacy for wound healing, and may be applicable to oral protein formulations for the treatment of intestinal mucosal erosions.

Airborne cat (Fel d I), dog (Can f I), and mite (Der I and Der II) allergen levels in the homes of Japan

We measured the airborne and floor dust allergen levels of the cat (Fel d I), dog (Can f I), and mite (Der I and Der II) allergens in 13 houses. Airborne allergens were sampled with a low-noise air sampler for 5 to 7 days in the living rooms where the inhabitants were living as usual. The mean levels of airborne Fel d I and Can f I in houses with cats or dogs were 5960 and 2880 pg/m3, respectively, which were about 160 and 100 times higher than levels of airborne Der I. In floor dust the mean levels of Fel d I and Can f I were 322 and 236 micrograms/gm fine dust, respectively, which were 59 and 10 times higher than the levels of Der I. These results suggest that the airborne cat and dog allergens might be important sources of allergens for persons who live in a house with those animals, because the absolute allergen levels in both the air and dust are significantly higher than those of mite.

Evaluation of phenylmethanesulfonyl fluoride (PMSF) as a tracer candidate mapping acetylcholinesterase in vivo

The availability of phenylmethanesulfonyl fluoride (PMSF), an irreversible cholinesterase inhibitor, for a tracer mapping acetylcholinesterase (AchE) in vivo in brain and other organs was evaluated using [35S]PMSF in mice and rats. [35S]PMSF was well taken up into the brain, heart and muscle, and the radioactivities were trapped in these organs. Pretreatment with non-labeled PMSF decreased 33-40% of the trapped radioactivities in the brain and other organs in mice. However, regional distribution of [35S]PMSF in rat brain did not correlate well with that of AchE activity, suggesting that the selectivity of PMSF toward AchE may be insufficient for use as an in vivo tracer mapping AchE.