3DFT-FISP MRI with gadopentetate dimeglumine in differential diagnosis of small liver tumors

OBJECTIVE

We assessed the value of dynamic sequential three-dimensional Fourier transformation (3DFT) MRI in differentiating various types of small liver tumors.

MATERIALS AND METHODS

Forty-seven patients with 65 liver masses < 3 cm in size (42 hepatocellular carcinomas, 11 hemangiomas, 12 metastatic tumors) were studied by 3DFT fast imaging with steady-state precession (FISP) MRI [TR(ms)/TE(ms)/flip angle (degree): 20/8/30]. The slab thickness was 21-35 mm, and there were seven partitions. The 3DFT-FISP MR images were obtained immediately after 0.1 mmol/kg of gadopentetate dimeglumine was administered intravenously over 2-3 s (early phase), 60 s after (late phase I), and 120 s after (late phase II).

RESULTS

Eighty-six percent of small hepatocellular carcinomas showed hyperintense enhancement relative to the surrounding liver parenchyma and iso- or hypointense enhancement with or without capsular enhancement in the late phase. Eighty-two percent of small hemangiomas showed peripheral globular enhancement in the early phase and total hyperintense or peripheral enhancement in the late phases. Ninety-two percent of the small metastatic liver tumors showed doughnut-like ring enhancement in the early phase.

CONCLUSION

By dynamic 3DFT-FISP MRI, we were able to accurately evaluate the hemodynamics and morphological findings of each type of small liver tumor.

The role of hydrated silica, titania, and alumina in inducing apatite on implants

Pure soluble silica prepared by a sol-gel method induced bone-like hydroxyapatite formation onto its surface when the silica was immersed in a simulated body fluid (SBF), whereas silica glass and quartz did not. This finding directly supports the hypothesis that hydrated silica plays an important role in biologically active hydroxyapatite formation on the surfaces of bioactive glasses and glass-ceramics, which leads to bone-bonding. Gel-derived titania is also a hydroxyapatite inducer because of its abundant TiOH groups. These results provide further insight into the unique osseointegration of titanium and its alloys. It is suspected that gel-derived titania develops an apatite layer by taking calcium and phosphate from the body fluid, thus producing bone-bonding. Although sufficient AlOH groups may remain in the alumina gel, they do not serve to initiate apatite generation when immersed in SBF. This phenomenon explains the fact that an intermediate fibrous tissue is usually found to separate the alumina implant from bone. One may infer that both abundant OH groups and negatively charged surfaces of gel-derived silica and titania are important for hydroxyapatite induction. material which possesses and/or develops both a negatively charged surface and abundant OH groups in a physiologically-related fluid is most likely to be an efficient apatite inducer. Such materials are suitable candidates to serve as bone-bonding biomaterials.

Five-year survival after transcatheter chemoembolization for hepatocellular carcinoma

The 5-year cumulative survival rate of 443 patients who underwent transcatheter chemoembolization (TCE) for non-resectable hepatocellular carcinoma (HCC) before December 1986 was 8.0%, and 29 patients survived for 5 years or more. Of these 29 patients, 25 were men and 4 were women; their mean age was 63.9 years. Macroscopic classification showed lesions of the single nodular type in 16 cases, the multiple nodular type in 10 cases, and the massive type in 3 cases; 12 of the single nodular lesions measured 5 cm or less in size. The TNM classification showed lesions of stage I in 3 cases, stage II in 14 cases, stage III in 6 cases, and stage IV in 6 cases. Lesions classified as Child A were found in 23 patients, and they were thus much more common than Child B lesions (2 patients) and Child C lesions (1 patient). The response was analyzed in relation to the use of iodized oil (Lipiodol). It was used in 215 of the patients, and the 5-year cumulative survival rate of those patients was 12.9% (23 of them survived for 5 years or more). Lipiodol was not used in 228 patients, and they showed a 5-year cumulative survival rate of 3.4%, with 6 patients surviving for 5 years or more. The 6 patients with stage III disease and the 6 with stage IV disease received Lipiodol. TCE with Lipiodol thus contributed greatly in prolonging the survival of patients with HCC complicated by intrahepatic metastases or intraportal tumor thrombi.

Isolation of flat revertants from human papillomavirus type 18 E6E7 transformed 3Y1 cells by transfection with a rat embryo fibroblast cDNA expression library

A rat embryo fibroblast (REF) cDNA expression library was transfected into 3Y1 cells transformed by human papillomavirus type 18 E6 and E7 genes and 10 flat revertants were isolated. These revertants expressed the same levels of E6 and E7 mRNA as the parent cells, but had greatly reduced ability to form colonies in soft agar. Suppression of transformation was dominant in cell hybrids generated by fusing each revertant with the parental transformed cells. Furthermore, loss of transfected cDNA was observed in re-transformed cell hybrids derived from one flat revertant. Overexpression of the cDNA suppresses the colony-forming efficiency of the cells transformed by E6 and E7 genes.

Separation of the sticky peptides from membrane proteins by high-performance liquid chromatography in a normal-phase system

The amphiphilic peptides obtained upon cleavage of membrane proteins, including numerous receptors, are recalcitrant to most separation techniques as a consequence of their limited solubility and tendency to aggregate and adsorb to surfaces. This paper describes HPLC systems that can separate these "sticky" peptides on silica and aminopropyl-modified silica columns with a mobile phase consisting of a mixture of chloroform/methanol/isopropylamine. The protocols developed have been applied to synthetic M1 and M2 peptides, which constitute part of the transmembrane domain of glutamate-gated ion-channel proteins. Four of these M1 and M2 peptides were separated from minor synthetic impurities, and a 23-mer was baseline separated from a 28-mer. The HPLC procedures have also led to purification of the 10 peptides resulting from cyanogen bromide cleavage of bacteriorhodopsin, peptides which have so far eluded HPLC separation despite numerous attempts. These HPLC protocols have been used to purify peptides ranging from 4 to 50 amino acids in high yield while the columns continued to resolve sharp peaks after more than 100 separation runs over a 6-month period. These new HPLC systems offer an efficient method for the isolation and analysis of this important albeit troublesome class of peptides.

[Risk factors of hepatitis C virus infection]

In order to clarify the risk factors of hepatitis C virus (HCV) infection, past medical histories, family histories of liver disease, and lifestyle factors (smoking and drinking habits) were compared between anti-HCV positive cases and anti-HCV negative controls. Studies were 433 anti-HCV positive cases and 298 negative controls, all of whom were out-patients with chronic hepatitis or liver cirrhosis. The findings were contrasted with the risk factors of hepatitis B virus (HBV) chronic infection. Multiple logistic regression analysis revealed the following findings. Prevalence of anti-HCV among patients with chronic hepatitis or liver cirrhosis increased with age, while prevalence of HBsAg decreased with age. Histories of blood transfusion were closely associated with the risk of HCV infection. Adjusted relative risk for patients with a history of blood transfusion was estimated to be 2.97 (95% confidence intervals: 1.88-4.71) in comparison with the risk for patients without it. Any family history of liver disease was not related with the risk of HCV infection, while mother's history of liver disease was significantly associated with the risk of chronic HBV infection (adjusted relative risk was 2.96 with 95% confidence intervals: 1.32-6.62).

Antineutrophil and myocardial protecting actions of a novel nitric oxide donor after acute myocardial ischemia and reperfusion of dogs

BACKGROUND

It has recently been demonstrated that myocardial ischemia and reperfusion results in a marked decrease in the release of nitric oxide (NO) by the coronary endothelium. NO may possess cardioprotective properties, possibly related to inhibition of neutrophil-related activities. We tested the hypothesis that a cysteine-containing nitric oxide donor compound, SPM-5185, would reduce infarct size and inhibit neutrophil-related activities (adherence to coronary vascular endothelium, accumulation).

METHODS AND RESULTS

The effects of intracoronary infusion of SPM-5185 were investigated in a 5.5-hour model of myocardial ischemia (1 hour) and reperfusion (4.5 hours) (MI-R) in anesthetized, open-chest dogs. SPM-5185 (500 nmol/L) or saline vehicle was infused for 4.5 hours into the left anterior descending coronary artery (LAD) at the time of reperfusion after 1 hour of LAD occlusion. MI-R in dogs receiving saline vehicle resulted in severe myocardial injury characterized by dyskinesis, a profound elevation of plasma creatine kinase, marked myocardial necrosis, and high cardiac myeloperoxidase (MPO) activity in the ischemic and necrotic zones. In contrast, treatment with SPM-5185 resulted in a modest restoration of regional function, a reduction of myocardial necrosis expressed as a percentage of the area at risk (12.5 +/- 3.2% versus 41.7 +/- 5.4%, P < .001), and significant reductions of MPO activity in the ischemic zone (0.8 +/- 0.1 versus 2.5 +/- 0.7 U/100 mg tissue, P < .05) and the necrotic zone (1.6 +/- 0.2 versus 3.3 +/- 0.6 U/100 mg tissue, P < .05). In additional studies, SPM-5185 (500 nmol/L) significantly (P < .001) attenuated the adherence of LTB4-stimulated canine neutrophils to autologous segments of coronary artery and attenuated the neutrophil-induced contraction of isolated coronary arterial rings.

CONCLUSIONS

SPM-5185 reduces myocardial necrosis and neutrophil accumulation in an acute model of canine myocardial ischemia and reperfusion. This reduction in myocardial cell injury may be partially related to the inhibitory actions of this novel NO donor on neutrophil adherence to the coronary endothelium.

Acadesine improves surgical myocardial protection with blood cardioplegia in ischemically injured canine hearts

BACKGROUND

Adenosine is a cardioprotective autacoid that exerts receptor-mediated protection from ischemia/reperfusion injury. In ischemically injured hearts, avoidance of ischemia/reperfusion injury with hypothermic chemical cardioplegia may be incomplete, and consequently, postischemic left ventricular (LV) function may be severely depressed and chamber stiffness increased. This study tested the hypothesis that the adenosine-regulating agent acadesine improves myocardial protection with hypothermic blood cardioplegia (BCP), resulting in better postischemic LV function and diastolic characteristics in hearts injured by 45 minutes of normothermic global ischemia.

METHODS AND RESULTS

Eighteen anesthetized (350 micrograms fentanyl citrate, 5 mg diazepam) dogs on total vented bypass were randomized to receive vehicle (n = 5), low-dose acadesine (LDA, 0.125 mg.kg-1.min-1, n = 6) or high-dose acadesine (HDA, 0.5 mg.kg-1.min-1, n = 7) continuously infused 30 minutes before global ischemia and discontinued 10 minutes after aortic cross-clamp removal. Hearts were protected with cold (4 degrees C) multidose (every 20 minutes) potassium BCP, which contained saline vehicle, 1 mg/L acadesine (LDA), or 4 mg/L acadesine (HDA) for a total of 1 hour of cardioplegic arrest. Postischemic LV function, assessed by the slope of the end-systolic pressure-volume (impedance catheter) relation, was depressed by 34 +/- 7% of baseline (5.6 +/- 1.0 versus 2.7 +/- 0.7 mm Hg/mL, P < .05) in vehicle. With LDA, there was variable improvement in postischemic function (5.1 +/- 1.3 versus 3.6 +/- 0.6 mm Hg/mL, P = .26 versus baseline). In contrast, there was complete postischemic functional recovery with HDA (5.9 +/- 0.6 versus 5.2 +/- 0.8 mm Hg/mL, P = .54). Postischemic chamber stiffness was preserved in both LDA and HDA.

CONCLUSIONS

We conclude that the higher dose of acadesine improves myocardial protection when used as a pretreatment and BCP adjuvant, resulting in better postischemic LV systolic function and diastolic characteristics.

[Surgical treatment of the patients with pulmonary atresia, ventricular septal defect associated with major aorto-pulmonary collateral arteries--a report of two cases]

Two patients undergoing corrective operation for pulmonary atresia with ventricular septal defect associated with major aortopulmonary collateral arteries (MAPCAs) were reported. Both patients underwent staged surgical repair, first stage: unifocalization, and second stage: Rastelli type operation. Case 1 was a 13-year-old female who had a confluent central pulmonary artery and 1 MAPCA, unifocalized at 10 years of age. After the corrective operation, the ratio between peak right ventricular and peak left ventricular pressure (pRV/LV) was 0.5 and she followed a satisfactory post-operative course. Case 2 was a 11-year-old female who had a severe hypoplastic central pulmonary artery (3 mm in diameter) and 3 MAPCAs, and she underwent unifocalization twice. After the corrective operation, pRV/LV was 0.65 and her postoperative course was also satisfactory.

Protection by disulfiram and diethyldithiocarbamate against hypoxia-induced lethality in mice

The effects of disulfiram (DS) and its major metabolite, diethyldithiocarbamate (DEDC), on the survival time under normobaric and hypobaric hypoxia were examined in mice. At an ambient temperature of 24 degrees C, DS at 0.5-3.0 mmol/kg (i.p.) caused a marked dose-dependent prolongation of the survival time in mice subjected to both types of hypoxia. DEDC also prolonged the survival time, but the effect was less at its higher doses with decreased brain superoxide dismutase. The maximum effects of DS and DEDC were found at 3 hr and 1 hr after injection, respectively. Of the metabolites of DEDC, the copper complex with DEDC caused a significant effect, whereas neither diethylamine nor carbon disulfide did. Furthermore, DS, DEDC and copper complex caused marked hypothermia, and the time course changes of hypothermia by DS and DEDC closely paralleled those of the degree of anti-hypoxic effects, respectively. At an ambient temperature of 36 degrees C, in which the body temperature was maintained near the normal level, both DS and DEDC still exhibited a weak anti-hypoxic effect. These results suggest that DEDC itself, formed as a metabolite of DS, and partly the copper complex produced the anti-hypoxic effect, which could not be explained by concomitant hypothermia alone.

Induction and morphology of hydroxyapatite, precipitated from metastable simulated body fluids on sol-gel prepared silica

Hydroxyapatite crystallization is induced at 37 degrees C by sol-gel prepared silica from metastable calcium phosphate solutions. The morphology of the apatite forming on the silica surface depends on the nature of the solutions. For example, apatite grew in a flake-like form at pH 7.4. The morphology changed to plate-like when the pH was adjusted to pH 7.2. At this lower pH, the apatite plate even exhibited a hexagonal feature, reflecting the unique hexagonal structure of hydroxyapatite. An increase in either Mg or P ion concentration of the fluid can cause apatite to grow in a rod-like shape while addition of F ions to the fluid leads to a perfect needle pattern. The flake geometry of apatite was not altered by increasing Ca concentration from 2.5 to 3.8 mM in the solution. From this we conclude that sol-gel prepared silica is an efficient apatite inducer and the morphology of the hydroxyapatite deposit is determined by factors of the fluid such as pH, Ca/P molar ratio, Mg and F concentrations.

Tendon insertions onto allografts pretreated with heat and/or bone surface demineralization

Tendon insertions onto allogeneic bone grafts were studied histologically and biomechanically in 132 rats. Before grafting, allogeneic bone was treated at different temperatures or partially demineralized or both. Mesenchymal cell and fibrous tissue invasion were easily recognized in non-heat-treated allograft groups and in groups with allografts incubated at 70 degrees; invasion was not observed in autoclaved (130 degrees) allograft groups. New bone formations were found between the tendon and the surface-demineralized allografts in the non-heat-treated and 70 degrees-treated bone groups but not in the autoclaved group. Allografts pretreated with heat demonstrated graft-insertion tensile strengths lower than in non-heat-treated and 70 degrees-treated allografts. Surface-demineralization enhanced graft-insertion tensile strengths in the non-heat-treated and 70 degrees-treated groups, whereas the tensile strength of attachments in noninductive, autoclaved allografts was not enhanced.

Serum lipoprotein(a) levels differ in different phenotypes of primary hyperlipoproteinemia

Previous studies have indicated that serum lipoprotein(a) [Lp(a)] levels are mostly under genetic control. We have attempted to determine whether serum Lp(a) levels differ in different phenotypes of primary hyperlipoproteinemia (HL). A total of 129 subjects with HL (three with type I, 43 with familial hypercholesterolemia [FH], 17 with type IIa [non-FH], 11 with type IIb, six with type III [E2/2], 44 with type IV, and five with type V) and 18 normolipidemic controls were included in the study. Thirty-two FH subjects were being treated with hypolipidemic agents, but none of the other subjects were receiving any medication. Fasting blood samples were collected for determination of both serum lipid and Lp(a) levels. Lp(a) level was measured by enzyme-linked immunosorbent assay. The 18 controls had serum Lp(a) concentrations of 18.0 +/- 14.5 mg/dL (mean +/- SD), and four of them had high serum Lp(a) levels (> or = 25 mg/dL). Serum Lp(a) concentrations in FH subjects tended to be higher than in the controls (30.5 +/- 25.0 mg/dL), and the incidence of high Lp(a) levels in FH subjects was significantly higher than in the controls (51% v 22%, P < .01). There was no difference between serum Lp(a) levels of FH subjects depending on whether they were receiving medication. In contrast, most of the subjects with selective hypertriglyceridemia had very low serum Lp(a) levels (1.5 +/- 0.7, 8.1 +/- 8.3, and 3.5 +/- 5.3 mg/dL in type I, IV, and V, respectively; P < .01 v controls).(ABSTRACT TRUNCATED AT 250 WORDS)

[Pacemaker implantations in children with regard to the site of implantation]

We reviewed thirty eight children, ranged 3 days to 15 years (mean, 7.2 years) of age, who underwent permanent pacemaker implantations in our hospital. Long-term results including the site of generator pocket were discussed. They are alive and well except two early and three late deaths that were not related to the pacemaker implantation. Twenty-seven epicardial and 11 endocardial electrodes were implanted at the initial operations. Thirteen pulse generators implanted in subaxillar position had no complications, otherwise, 12 subcostal implantation resulted 4 skin necrosis and 3 lead fractures. Eleven anterior chest implantations used for relatively older children resulted in one skin necrosis. We recommend subaxillar implantation for children, especially for small infants. The replacements of pulse generators due to battery depletion were done between 1.7 to 5.5 years (mean 4.0 years). Because epicardial implanted electrodes often show higher stimulation threshold than epicardial ones, pacing rate should be as lowered as possible if the patient had no symptom. Stab-in leads placed on the atrial wall sometimes caused the elevation of stimulation threshold and undersensing. We conclude that the development of more reliable and stable electrode is desired to improve the long term results of pacemaker therapy in children although the improvement of pulse generator itself and the operative procedure.

Growth-promoting action of adenosine-containing dinucleotide on neuroblastoma cells: detection of adenosine-cytidine dinucleotide (ApCp) in neurofibroma (NF1) extracts

Neurofibroma type 1 tissue was investigated for the presence of growth-promoting activity on human neuroblastoma cells. The activity was isolated by gel filtration and reversed-phase column chromatographs from neurofibroma type 1 extracts. An adenosine-containing dinucleotide (adenylyl(3'-5')cytidine-3'-phosphate) was identified as one of the major components of the activities by its enzymatic fragmentation and liquid chromatography/mass spectrometry. Synthetic adenosine-containing dinucleotide derivatives such as cytidyl(3'-5')adenosine, cytidyl(2'-5')adenosine, adenylyl(3'-5')cytidine, and adenylyl(2'-5')cytidine showed a similar action. Cytidyl(3'-5')adenosine, cytidyl(2'-5')adenosine, and adenylyl(2'-5')cytidine, which are able to release a free adenosine through enzymatic hydrolysis, in particular elicited a strong activity corresponding to that of adenosine with the highest action. These results suggest that neuroblastoma cells are able to use adenosine-containing dinucleotides as well as mononucleotides for their survival and proliferation.

Neurotrophic action of gliostatin on cocultured neurons with glial cells

Gliostatin is a polypeptide factor (apparent M(r) = 100 k with a homodimeric structure comprising two 50 kDa subunits) acting on cortical neurons (neurotrophic action) as well as astrocytic cells (growth inhibition). Under the coculture system of cerebral cortical neurons and astrocytes from fetal rats (E15 or E16), the neurotrophic action of gliostatin was examined immunocytochemically. Immunostaining by an anti-neurofilament (NF) monoclonal antibody visualized a marked neurite-outgrowth and interconnecting bundles of neuritic processes induced by gliostatin in the coculture system. Neurons stimulated by gliostatin formed dense aggregates in clumps, while neurons in control coculture spread out. Gliostatin has also shown survival-promoting effects on neurons. Furthermore, it was shown that gliostatin induced the differentiation of protoplasmic astrocytes to fibrous astrocytes. These results further support our previous contention that gliostatin plays physiological roles on neuronal and glial development.

Physicochemical characterization of a ouabain isomer isolated from bovine hypothalamus

Recent reports have shown the presence of a ouabain-like inhibitor of Na+/K(+)-ATPase in humans. We have purified a bovine hypothalamic Na+/K(+)-ATPase inhibitory factor (HIF) by using affinity chromatography combined with HPLC. This inhibitor has a molecular weight of 584 as determined by ion-spray mass spectrometry, making it isobaric with ouabain. Glycosidase treatment or acid hydrolysis of HIF released only L-rhamnose, the hexose isomer found in ouabain, as detected by chiral GC/MS. Additionally, enzymatically generated desrhamnosyl HIF was found to have a molecular weight of 438, as does ouabagenin, the aglycone of ouabain. HIF and its aglycone were indistinguishable from ouabain and ouabagenin, respectively, by reversed-phase HPLC retention times. However, derivatization with naphthoylimidazole followed by HPLC revealed different retention times for naphthoylation products of HIF and ouabain. Subsequent CD spectroscopy on isolated naphthoylation products of HIF and ouabain confirmed that they were different. This study provides chromatographic and spectroscopic evidence that ouabain and HIF are isomeric cardenolides. The structural difference is presumed to account for the significant differences in biological properties observed for HIF and ouabain.

Selective antagonism of native and cloned kainate and NMDA receptors by polyamine-containing toxins

Antagonism of rat excitatory amino acid receptors by a synthetic analog [philanthotoxin-343 (PhTX-343)] of a polyamine amide, wasp toxin (philanthotoxin-433) and a structurally related spider toxin, argiotoxin-636 (ArgTX-636), was examined in Xenopus oocytes injected with rat brain RNA or RNA transcribed from the excitatory amino acid receptor clones GluR1, GluR2 and NMDAR1. Antagonism of both kainate- and N-methyl-D-aspartate (NMDA)-elicited responses by PhTX-343 and ArgTX-636 was reversible, noncompetitive and partly voltage-dependent. Dose-inhibition curves were constructed using EC50 concentrations of kainate (100 microM) and N-methyl-D-aspartate (33 microM) in the presence of variable concentrations of ArgTX-636 and PhTX-343. In oocytes injected with rat brain RNA, IC50s for antagonism of kainate-induced currents were similar, i.e., 0.07 microM and 0.12 microM for ArgTX-636 and PhTX-343, respectively, whereas IC50s for antagonism of NMDA-induced currents were dissimilar, i.e., 0.04 microM for ArgTX-636 and 2.5 microM for PhTX-343. In oocytes expressing NMDAR1, IC50s were similar to those for the antagonism of NMDA-induced currents of oocytes injected with rat brain RNA. PhTX-343 and ArgTX-636 were more or less equally potent (IC50s were 2.8 microM and 3.4 microM, respectively) antagonists of the response of GluR1 to 100 microM kainate. However, GluR1 was approximately 50 times less sensitive to the toxins than non-N-methyl-D-aspartate receptors expressed in oocytes injected with rat brain RNA. Receptors co-expressed from GluR1 + GluR2 were virtually insensitive to PhTX-343 (IC50 = 270 microM) and to ArgTX-343 (IC50 approximately 300 microM).

Lectin binding and expression of blood group-related antigens in carcinoma-in-situ and invasive carcinoma of urinary bladder

To determine whether histochemical reactivities of carcinoma-in-situ of the urinary bladder differ from those of invasive transitional cell carcinoma, we tested a profile of eight different lectins and three antibodies directed against blood group-related antigens for 15 cases of carcinoma-in-situ and 26 cases of non-papillary (6 superficially and 20 deeply) invasive transitional cell carcinoma that had been diagnosed according to the histopathological criteria of the International Union against Cancer. For biotin-labelled lectins and monoclonal antibodies to mouse blood group-related antigens, the avidin-biotin peroxidase complex method was applied. Positive histochemical reactions of peanut agglutinin without neuraminidase treatment--PNA N(-)--in the 20 deeply invasive tumour cases were significantly higher than those in the 15 carcinoma-in-situ cases (P < 0.05). In contrast, the reactions of blood group-related antigens in the 20 deeply invasive tumour cases were significantly lower than those in the 15 carcinoma-in-situ cases or the 11 normal controls (P < 0.05). The results confirm previously reported studies of the staining of PNA N(-) and blood group-related antigens on carcinoma-in-situ and invasive tumours of urothelial organs. The application of lectins and blood group-related antigens to the histopathology of urinary bladder cancer may be helpful in the differential diagnosis of carcinoma-in-situ from invasive cancer, but neither PNA N(-) nor blood group-related antigens can be solely reliable in this.

Receptor-mediated cardioprotective effects of endogenous adenosine are exerted primarily during reperfusion after coronary occlusion in the rabbit

BACKGROUND

We hypothesized that: (1) endogenous adenosine released during ischemia/reperfusion reduces infarct size and preserves postischemic myocardial blood flow by receptor-mediated mechanisms and (2) this cardioprotection is exerted predominantly during reperfusion.

METHODS AND RESULTS

Sixty-one anesthetized open-chest rabbits subjected to 30 minutes of coronary occlusion and 120 minutes of reperfusion were randomized to six groups: group 1, saline (Vehicle) (n = 10) to allow receptor interaction of endogenous adenosine (Ado) during ischemia/reperfusion; group 2, Ado-receptor blockade during both ischemia and reperfusion with intravenous 8-p-sulfophenyltheophyl-line (10 mg/kg) (SPTIR, n = 10); group 3, Ado-receptor blockade in multiple doses during both ischemia and reperfusion (MSPTIR, n = 11); group 4, blockade during reperfusion (SPTR, n = 10); group 5, blockade during reperfusion with PD115,199 (6 mg/kg) (PDR, n = 10); and group 6, blockade after 30 minutes of reperfusion (SPT30R, n = 10) to allow adenosine receptor interaction during early reperfusion. Transmural myocardial blood flow in the area at risk (Ar) (15-microns radiolabeled microspheres) was reduced by 96.7% in all groups, from 137.9 +/- 15.5 to 4.5 +/- 1.4 mL.min-1 x 100 g-1 (P < .001). MSPTIR, SPTIR, and SPTR significantly attenuated reactive hyperemia at 15 minutes of reperfusion (144 +/- 18, 141 +/- 22, and 144 +/- 20 mL.min-1 x 100 g-1, respectively) compared with Vehicle (257 +/- 40 mL.min-1 x 100 g-1, P < .05). This attenuation was more pronounced in the necrotic zone than in the nonnecrotic zone. Reactive hyperemia at 15 minutes of reperfusion in SPT30R group was comparable to the Vehicle group. At 120 minutes of reperfusion, blood flow in Ar was significantly less in MSPTIR (77 +/- 10), SPTIR (82 +/- 9), and SPTR (80 +/- 11) compared with Vehicle (140 +/- 12) and SPT30R (105 +/- 24 mL.min-1 x 100 g-1). Infarct size (by triphenyltetrazolium chloride), expressed as a percent of Ar, was largest in the multiple-dose group with blockade during both ischemia and reperfusion (MSPTIR, 51.9 +/- 2.3%) and was significantly increased also in single-dose SPTIR (39.1 +/- 2.2%) compared with 25.7 +/- 1.7% in the Vehicle group (P < .05). Ado-receptor blockade only during reperfusion was associated with 14% smaller infarct size in the SPTR group than the MSPTIR group (P < .05). In contrast, Ado-receptor blockade after 30 minutes of reperfusion (SPT30R) did not increase infarct size (27.9 +/- 2.2%), which was comparable to infarct size in the Vehicle group.

CONCLUSIONS

We conclude that: (1) endogenous adenosine released from the myocardium during ischemia/reperfusion reduces infarct size by receptor-mediated mechanisms and (2) Ado-mediated cardioprotection is most pronounced during the early phase of reperfusion.

Postcardioplegia acute cardiac dysfunction and reperfusion injury

In cardiac surgery, an obligatory period of ischemia is imposed in order to provide a convenient operative field. Brief periods of ischemia produce systolic and diastolic abnormalities related to pathology occurring during ischemia per se (ischemic injury) or expressed after the onset of reperfusion (reperfusion injury). In the surgical setting, ischemia may be encountered preoperatively with preexisting coronary disease, hypotension, or ventricular fibrillation, between intermittent infusions of cardioplegia solutions, or as a result of maldistribution of cardioplegia solution. The potential for reperfusion injury exists not only at the time of cross-clamp removal, but also with each infusion of cardioplegia solution. Infusion of cardioplegic solution is, in fact, a form of reperfusion to previously ischemic myocardium. Ischemic injury and reperfusion injury are intimately linked in that the severity of ischemia sets the stage for and determines, in part, the extent of reperfusion injury. Mild-to-moderate systolic dysfunction, which may be called "postcardioplegia stunning," remains a significant complication after cardiac surgery. More significant postoperative functional depression may occur in hearts with severe preoperative dysfunction, and in operations requiring long cross-clamp times. In addition, the failure to adequately distribute cardioplegic solution to all areas of the myocardium because of coronary stenoses, high coronary resistance or inadequate delivery pressure-flow relations, contributes to postcardioplegia dysfunction. However, the cardioplegic solution itself may also contribute to postcardioplegic dysfunction by creating temporary ionic and metabolic abnormalities. In addition, systemic hypocalcemia or hyperkalemia resulting from using large doses of cardioplegic solution may temporarily aggravate postcardioplegic mechanical dysfunction. Current formulations and strategies for delivery of cardioplegia solutions are designed to address the various contributors to both ischemic and reperfusion injury that may impact on postoperative mechanical performance. Ischemic injury is avoided by reducing myocardial oxygen demand by engaging immediate arrest and cooling the heart to approximately 10 degrees centigrade, and intermittently infusing solution to reoxygenate the myocardium, maintain hypothermia, and wash out accumulated metabolites. Reperfusion injury may be avoided by infusing hyperosmotic solutions at moderate pressures, and by incorporating oxygen radical scavengers or inhibitors to reduce membrane lipid peroxidation, myocellular and microcirculatory (endothelium) damage.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative study of phototactic and photophobic receptor chromophore properties in Chlamydomonas reinhardtii

The motile, unicellular, eukaryotic alga Chlamydomonas reinhardtii exhibits two distinct behavioral reactions to light stimuli, phototaxis and the photophobic response. Both are mediated by retinal-containing receptors. This paper focuses on a direct comparison of the two photoresponses and the chromophore requirements for their photoreceptor(s). Using computerized motion analysis assays for phototaxis and photophobic responses by the same populations of cells, we measured the ability of various isomers and analogues of retinal to reconstitute photobehavior in the pigment-deficient mutant FN68. The results indicate that photophobic and phototaxis responses each require chromophores with an all-trans polyene chain configuration, planar ionone ring/polyene chain conformation, and the ability to isomerize around the retinal C13-C14 double bond. One difference between the two behaviors is that the photophobic response becomes highly desensitized after light stimuli to which the phototaxis response does not become desensitized, indicating the existence of at least one distinct step in the photophobic response pathway. A second difference is that the retinal regeneration of the photophobic response but not of phototaxis is inhibited by a 5-membered ring 13-trans-locked analogue. While showing close similarity in the chromophore structural requirements of the two behaviors, the results indicate that differences exist between the two responses at the level of their photoreceptor proteins and/or in their transduction processes.

Association of HLA-A24 with complete beta-cell destruction in IDDM

A sensitive C-peptide immunoreactivity radioimmunoassay demonstrated the presence of subtle, but definite residual beta-cell function in patients with IDDM of long duration. Although HLA antigens are known to influence susceptibility to IDDM, their contribution to the extent of pancreatic beta-cell destruction has not yet been examined extensively. We studied the relationship between residual beta-cell function and HLA class I and class II antigens in 111 unrelated Japanese IDDM patients. Using the sensitive C-peptide immunoreactivity radioimmunoassay, the presence or absence of residual beta-cell function was evaluated by the C-peptide immunoreactivity response to a 100-g oral glucose load. DNA typing for HLA-DQA1 and HLA-DQB1 antigens was performed in addition to serological typing of HLA-A, HLA-B, HLA-C, and HLA-DR antigens. A C-peptide immunoreactivity response > 0.033 nM was regarded as an indication of the presence of residual beta-cell function, not the assay error. Surprisingly, 35 of 37 (94.6%) patients without residual beta-cell function had HLA-A24, whereas only 39 of 74 (52.7%) patients with residual beta-cell function had this antigen (corrected P = 9.795 x 10(-6). Any other HLA antigens, including the DR and DQ loci, showed no difference in the frequency with regard to residual beta-cell function. The duration of diabetes was similar between the groups with and without residual beta-cell function.(ABSTRACT TRUNCATED AT 250 WORDS)