Simplified PET quantitation of myocardial glucose utilization

The purpose of this study was to validate experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using 14C-deoxyglucose and assess its clinical feasibility for myocardial PET.

METHODS

To validate the BRI method, glucose utilization in myocardial and skeletal muscle was studied in rats with 14C-deoxyglucose after increasing doses of oral glucose loading. To assess clinical feasibility of the method, the BRI was applied to nine patients undergoing myocardial PET and compared to rMGU measured by the deoxyglucose model of Sokoloff et al. and by Patlak graphical analysis. The normal range of myocardial FDG uptake expressed as the BRI was estimated with four normal volunteers.

RESULTS

In skeletal muscle, a dose-dependent increase of glucose utilization was observed during oral glucose loading with doses up to 4 mg/g. In the myocardium, glucose utilization increased with a glucose loading dose of up to 1 mg/g without increasing further at greater glucose doses. Ratios of maximal glucose utilization in glucose-loaded rats to 19-hr fasted rats (controls), expressed as the BRI for left and right ventricular myocardium and skeletal muscle were 4.16, 3.74 and 7.39, respectively. Glucose utilization of right ventricular myocardium was approximately 70% of left ventricular myocardium for all glucose-loaded conditions. For patients, the BRI correlated with rMGU; four of these patients had a constant plasma glucose concentration.

CONCLUSION

Myocardial BRI is a sensitive indicator of rMGU that does not require dynamic data acquisition or constant plasma glucose concentrations.

Improvement of nasal bioavailability of luteinizing hormone-releasing hormone agonist, buserelin, by cyclodextrin derivatives in rats

The effects of chemically modified cyclodextrins on the nasal absorption of buserelin, an agonist of luteinizing hormone-releasing hormone, were investigated in anesthetized rats. Of the cyclodextrins tested, dimethyl-beta-cyclodextrin (DM-beta-CyD) was the most effective in improving the rate and extent of the nasal bioavailability of buserelin. Fluorescence spectroscopic studies indicated that the cyclodextrins formed inclusion complexes with buserelin, which may reduce the diffusibility of buserelin across the nasal epithelium and may participate in the protection of the peptide against enzymatic degradation in the nasal mucosa. Additionally, the cyclodextrins increased the permeability of the nasal mucosa, which was the primary determinant based on the multiple regression analysis of the nasal absorption enhancement of buserelin. Scanning electron microscopic observations revealed that DM-beta-CyD induced no remarkable changes in the surface morphology of the nasal mucosa at a minimal concentration necessary to achieve substantial absorption enhancement. The present results suggest that DM-beta-CyD could improve the nasal bioavailability of buserelin and is well-tolerated by the nasal mucosa of the rat.

Structures of genomic and complementary DNAs coding for Pleurotus ostreatus manganese (II) peroxidase

To study the mechanism of regulation and structure/function relationship of the Pleurotus ostreatus manganese (II) peroxidase (MnP), we amplified the full-length genomic and complementary DNAs for the major isozyme of the MnP mainly by the cassette-primer PCR technique and then sequenced them. The cDNA contained an open reading frame of 1083 bp encoding for a polypeptide of 361 amino-acid residues, including the suggested signal peptide of 29 amino-acid residues with a prepro structure. The predicted amino-acid sequence of the protein shared several common characteristics with those of fungal lignin and manganese (II) peroxidases. We could find a suggested metal response element and two heat-shock element-like sequences in the 5'-flanking region of the structural gene. The structural gene contained 15 introns, many of which lie identical to those in lignin peroxidase genes rather than to those in the known MnP genes.

[Daily oral low-dose etoposide therapy for aged patients with relapsed aggressive lymphoma]

Two patients with relapsed Non-Hodgkin's lymphoma (NHL) were treated with oral administration of etoposide. In these patients, long-term hematological remission was obtained. One patient was a 76-year-old man, who was successfully treated with CHOP for diffuse large cell NHL stage III B. One year after obtaining CR, he was admitted to our hospital for enlargement of lymph node. Rebiopsy of lymph node made a diagnosis of relapse from NHL. A new regimen of oral administration of etoposide treatment was employed. Hematological remission was obtained and continued for 3 years. Without interfering with his quality of life. The other patient was a 74-year-old man, who was treated with 6 cycles of CHOP for diffuse large cell NHL stage IV B. The patient attained complete remission following an additional 2 cycles of COMLA therapy. Eight years later, he was admitted for enlargement of lymph node. Rebiopsy of lymph node provided the basis for a diagnosis of relapse from NHL. Oral administration of etoposide treatment was started. Hematological remission was obtained and has been continued until now. These results show that oral administration of etoposide treatment is effective for some patients with recurrent NHL.

CT evaluation of hepatic tumors: comparison of CT with arterial portography, CT with infusion hepatic arteriography, and simultaneous use of both techniques

OBJECTIVE

We hypothesized that CT with arterial portography (CTAP) might depict tumors undetected by CT with infusion hepatic arteriography (CTIHA), and the converse. Accordingly, we compared the detection rate of malignant tumors using CTAP, CTIHA, and simultaneous use of both techniques to determine whether CTIHA can be used to distinguish malignant from benign hepatic nodules.

SUBJECTS AND METHODS

Fifty-four candidates for partial liver resection who underwent combined CTAP and CTIHA were studied. Histopathologic study confirmed 77 malignant and 15 benign nodules in these patients. CTAP, CTIHA, and combined CTAP and CTIHA were used by three observers before surgery, and the sensitivities of the three methods in detecting malignant tumors were compared. Contrast-enhancement patterns of the nodules on CTIHA scans were determined.

RESULTS

Sixty-eight malignant nodules (88%) were detected with CTAP, 64 (83%) with CTIHA, and 69 (90%) with simultaneous interpretation of both scans. These differences were not significant. CTIHA showed 16 malignant and 12 benign small nodules. Of these, 13 malignant and two benign nodules had rim enhancement. Use of rim enhancement as the criterion for malignancy of these small nodules gave an accuracy rate of 82%.

CONCLUSION

CTAP, CTIHA, and simultaneous use of both techniques are similar in their ability to detect malignant hepatic tumors. CTAP alone is recommended for the detection of malignant hepatic tumors. CTIHA is of value in differentiating malignant from benign small nodules.

Direct measurement of high-density lipoprotein cholesterol in serum with polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin

We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective catalytic activities towards lipoprotein fractions, with the reactivity increasing in the order: low-density lipoprotein < very-low-density lipoprotein approximately chylomicron < HDL. In the presence of magnesium ions, alpha-cyclodextrin sulfate reduced the reactivity of cholesterol, especially in chylomicrons and very-low-density lipoprotein, without the need for precipitation of those lipoprotein fractions. The combination of PEG-modified enzymes with alpha-cyclodextrin sulfate provided selectivity for the determination of HDL-cholesterol in serum in the presence of a small amount of dextran sulfate without the need for precipitation of lipoprotein aggregates. The results of the HDL-cholesterol assayed in serum by this direct method correlated well with those obtained by precipitation-based methods and also that by an ultracentrifugation method.

Direct measurement of high-density lipoprotein cholesterol in serum with polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin

We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective catalytic activities towards lipoprotein fractions, with the reactivity increasing in the order: low-density lipoprotein &lt; very-low-density lipoprotein approximately chylomicron &lt; HDL. In the presence of magnesium ions, alpha-cyclodextrin sulfate reduced the reactivity of cholesterol, especially in chylomicrons and very-low-density lipoprotein, without the need for precipitation of those lipoprotein fractions. The combination of PEG-modified enzymes with alpha-cyclodextrin sulfate provided selectivity for the determination of HDL-cholesterol in serum in the presence of a small amount of dextran sulfate without the need for precipitation of lipoprotein aggregates. The results of the HDL-cholesterol assayed in serum by this direct method correlated well with those obtained by precipitation-based methods and also that by an ultracentrifugation method.

Retrievable IVC filter: preliminary in vitro and in vivo evaluation

PURPOSE

To develop an inferior vena cava (IVC) filter that is retrievable even after neointimal formation and incorporation into the caval wall.

MATERIALS AND METHODS

Eight filters were placed percutaneously in the infrarenal IVC of eight dogs. Four weeks after placement, percutaneous retrieval of the filters was attempted. Vena cavograms were obtained before and immediately after retrieval. Three dogs were killed immediately after the retrieval procedure was completed. In the other five dogs, follow-up vena cavography was performed 4-14 weeks after retrieval, and autopsy was performed.

RESULTS

The filters were placed and retrieved successfully in all eight dogs. No migration, caval penetration, or tilting occurred. The IVCs were completely patent both before and immediately after retrieval in all eight dogs. In the three dogs killed immediately after retrieval, neointimal hyperplasia was seen around the struts, but there was no detachment. Delayed stenosis was not seen in any of the five dogs that were followed up, and the inner surface of the caval wall was smooth.

CONCLUSION

This IVC filter can be easily placed and safely retrieved percutaneously, even after neointimal formation.

Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome

PURPOSE

To determine the factors that may be used to predict outcome of stent placement in patients with malignancies obstructing the superior or inferior vena cava.

MATERIALS AND METHODS

Gianturco stents were placed in 39 patients with malignant obstruction of the superior (n = 16) or inferior (n = 23) vena cava. Thirteen patients with obstruction of the superior vena cava received radiation therapy and/or chemotherapy at some time in their course of treatment. Computed tomographic (CT) scans were obtained in all patients. The authors analyzed treatment outcome with the location, length, and CT appearance of obstruction.

RESULTS

Venous congestive symptoms disappeared after stent placement in 35 patients and remained in four. Symptoms did not recur during 1-13-month follow-up in 32 of the 35 patients in whom the symptoms disappeared. Nonfatal complications were observed in nine patients. Results of multivariate analysis showed that the outcome of stent placement is best predicted by the appearance of obstructions on CT scans irrespective of the location and length of the lesions.

CONCLUSION

Good results can be expected from placement of Gianturco stents except when CT shows the obstruction to be totally enveloped by tumor.

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.