Identification and characterization of IL-2 hyper-responsive NZB/WF1 CD5- B cells

The responsiveness of CD5- and CD5+ B cells of BALB/c and NZB/WF1 mice to various cytokines was examined with respect to their growth and differentiation. BALB/c splenic CD5- B cells required longer incubation with IL-2 or pretreatment with IL-4 to respond to IL-2 by DNA synthesis, whereas NZB/WF1 CD5- B cells were highly competent to IL-2. Flow cytometric analysis demonstrated that NZB/WF1 and BALB/c CD5- B cells had higher and intermediate proportions of B cells positive for IL-2R beta, respectively. On the other hand, BALB/c and NZB/WF1 splenic CD5+ B cells consisted of lower proportion of B cells positive for IL-2R beta than did their corresponding CD5- B cells and grew meagerly in response to IL-2. Peritoneal exudative CD5+ B cells of NZB/WF1 mice lacked IL-2R beta mRNA expression and failed to respond to IL-2. Although both BALB/c and NZB/WF1 CD5- B cells pretreated with anti-IgM, IL-4, and IL-5 responded to IL-2 by DNA synthesis, only BALB/c CD5- B cells developed into IgM-producing cells. Furthermore, BALB/c, but not NZB/WF1 CD5-, B cells pretreated with anti-IgM and IL-5 responded to IL-2 by IgM production without DNA synthesis. Thus, cross-talk between IL-4 and IL-2 operated in the growth responses of both BALB/c and NZB/WF1 splenic CD5- B cells, whereas cross-talk between IL-5 and IL-2 operated only in the differentiation of BALB/c CD5- B cells, providing us with another intriguing functional abnormality of NZB/WF1 B cells.

Identification and characterization of IL-2 hyper-responsive NZB/WF1 CD5- B cells

The responsiveness of CD5- and CD5+ B cells of BALB/c and NZB/WF1 mice to various cytokines was examined with respect to their growth and differentiation. BALB/c splenic CD5- B cells required longer incubation with IL-2 or pretreatment with IL-4 to respond to IL-2 by DNA synthesis, whereas NZB/WF1 CD5- B cells were highly competent to IL-2. Flow cytometric analysis demonstrated that NZB/WF1 and BALB/c CD5- B cells had higher and intermediate proportions of B cells positive for IL-2R beta, respectively. On the other hand, BALB/c and NZB/WF1 splenic CD5+ B cells consisted of lower proportion of B cells positive for IL-2R beta than did their corresponding CD5- B cells and grew meagerly in response to IL-2. Peritoneal exudative CD5+ B cells of NZB/WF1 mice lacked IL-2R beta mRNA expression and failed to respond to IL-2. Although both BALB/c and NZB/WF1 CD5- B cells pretreated with anti-IgM, IL-4, and IL-5 responded to IL-2 by DNA synthesis, only BALB/c CD5- B cells developed into IgM-producing cells. Furthermore, BALB/c, but not NZB/WF1 CD5-, B cells pretreated with anti-IgM and IL-5 responded to IL-2 by IgM production without DNA synthesis. Thus, cross-talk between IL-4 and IL-2 operated in the growth responses of both BALB/c and NZB/WF1 splenic CD5- B cells, whereas cross-talk between IL-5 and IL-2 operated only in the differentiation of BALB/c CD5- B cells, providing us with another intriguing functional abnormality of NZB/WF1 B cells.

Lack of association of the transporter associated with antigen processing with Japanese insulin-dependent diabetes mellitus

The transporter associated with antigen processing (TAP) encoded in the major histocompatibility complex (MHC) class II region is a molecule required for endogenous antigen processing. We have typed TAP polymorphism in 95 Japanese patients with insulin-dependent diabetes mellitus (DDM) and 75 normal controls. Amino acid substitutions at positions 333 and 637 of TAP1 and at positions 379, 665, and 687 of TAP2 were typed by the polymerase chain reaction (PCR)-sequence-specific oligonucleotide method. In addition, DNA typing of human leukocyte antigen (HLA)-DQA1 and -DQB1 loci was performed by the PCR-restriction fragment length polymorphism method. There was no significant difference between IDDM patients and normal controls in the frequencies of TAP1 and TAP2 alleles. On the contrary, the HLA-DQ locus showed a strong association with IDDM in the same series of subjects. The frequencies of HLA-DQA1*0301 and -DQB1*0401 were increased significantly and those of HLA-DQA1*0103, -DQB1*0501, -DQB1*0601 and -DQB1*0602 were decreased significantly in Japanese IDDM patients compared with normal controls. Positive linkage disequilibrium was observed between HLA-DQB1*0303 and TAP2C and between HLA-DQB1*0401 and TAP2B. Negative linkage disequilibrium was observed between HLA-DQA1*0103 and TAP2A. Even when subjects with HLA-DQA1*0103, -DQA1*0301, -DQB1*0302, -DQB1*0303, and -DQB1*0401 were considered separately, no significant differences was found in the distribution of TAP1 and TAP2 alleles between IDDM patients and normal controls. We conclude that it is not TAP but HLA-DQ that exhibits a primary association with Japanese IDDM.

Relief of opsin desensitization and prolonged excitation of rod photoreceptors by 9-desmethylretinal

The 9-methyl group of 11-cis-retinal plays a crucial role in photoexcitation of the visual pigment rhodopsin. A hydrogen-substituted analogue, 11-cis-9-desmethylretinal, combines with opsin to form a pigment that produces abnormal photoproducts and diminished activation of the GTP-binding protein transducin in vitro. We have measured the formation of this analogue pigment in bleached salamander rods and determined the size and shape of its quantal response. In addition, we have characterized the influence of opsin and newly formed analogue pigment on the quantal response to native porphyropsin. We find that, as 11-cis-9-desmethylretinal combines with opsin in bleached rods, the amplitude of the quantal response from residual native pigment is elevated by approximately 7.5-fold to 0.15 +/- 0.09 pA, a value close to the amplitude of the quantal response before bleach (0.31 +/- 0.10 pA). When activated by light, the new analogue pigment produces a quantal response that is approximately 30-fold smaller and decays approximately 5 times more slowly than that of native pigment in unbleached cells. We conclude that the 9-methyl group of retinal is not critical for conversion of opsin to its nondesensitizing state but that it is critical for the normal processes of activation and deactivation of metarhodopsin that give rise to the quantal response.

Coronary artery endothelial dysfunction after global ischemia, blood cardioplegia, and reperfusion

This study tests the hypothesis that blood cardioplegia (BCP) attenuates endothelial dysfunction related to nitric oxide after global normothermic ischemia, cardioplegic arrest, and reperfusion in anesthetized open-chest dogs placed on cardiopulmonary bypass. The dogs were divided into five groups to identify the time when endothelial injury occurred: group 1 = control without ischemia; group 2 = 45 minutes of normothermic ischemia only; group 3 = 45 minutes of normothermic ischemia plus unmodified reperfusion; group 4 = 45 minutes of ischemia plus intermittent BCP without reperfusion; and group 5 = ischemia plus BCP and reperfusion. In vitro coronary vascular relaxation responses to the nitric oxide stimulator acetylcholine (endothelium-dependent, receptor-dependent), the calcium ionophore A23187 (endothelium-dependent, receptor-independent), and acidified NaNO2 (endothelium-independent) were measured at the end of the protocol. Maximum in vitro coronary vascular responses to acetylcholine were similar among groups 1, 2, and 4, indicating an absence of endothelial injury. In contrast, significantly impaired relaxations to acetylcholine were demonstrated in the two reperfused groups (groups 3 and 5). Relaxation responses to A23187 and NaNO2 were not altered markedly in any group. Electron microscopy showed intact endothelium in groups 1, 2, and 4. However, moderately severe endothelium damage was seen in groups 3 and 5. We conclude that morphologic and functional endothelial damage occurs after blood reperfusion with or without BCP, and 1-hour hypothermic BCP arrest after normothermic ischemia is not associated with extension of endothelial damage.

[Reoperation after corrective surgery for tetralogy of Fallot]

Thirty-two of 460 patients (6.9%) who had corrective surgery for tetralogy of Fallot in our institute between January, 1955 and March, 1994 required intracardiac reoperation. The indications for reoperation included residual lesions alone or combination of other lesions. The reoperation consisted of a new patch or direct closure of a residual ventricular septal defect in 28 (73%), reconstruction of a residual pulmonary stenosis in 18 (47%) and pulmonary regurgitation in 6 (16%), repair of tricuspid regurgitation in 11 (29%), recurrent infective endocarditis in 5 (13%), repair of a left ventricle-right atrium communication in 4 (11%). Six patients (19%) had required second reoperation of recurrent infective endocarditis in 3, other three patients required the repair of tricuspid valve disease. There were one operative death (3%) in reoperation and one death (17%) in second reoperation. Three patients (9%) died at follow-up periods of 1-21 years (mean of 9.6 years). Twenty-seven patients (84%) survived operation and 24 (89%) are now in NYHA class I and 3 patients are in class II. Reoperation after correction of tetralogy of Fallot is able to perform with low mortality and with excellent long-term results.

Plasmenylethanolamine in human intestinal mucosa detected by an improved method for analysis of phospholipid

Analysis of phospholipid and their fatty acid composition of human intestinal mucosa was performed by an method elaborated to analyze the limited amount of sample with 2-dimensional TLC followed by lipid-phosphorus determination. Using this method, plasmenylethanolamine was detected in human intestinal mucosa and accounted for about 7% of phospholipid in small and large intestinal mucosa. The amounts of polyunsaturated fatty acids of phosphatidylethanolamine were higher than those of other phosphoglycerides in intestinal mucosa, hence, inflammation-related eicosanoids may originate from ethanolamine containing phospholipid.

[Surgical treatment and long-term results of congenital heart disease in adults: early and late follow-up studies in 231 cases]

In a past one decade from January 1981 to August 1991, 231 patients over 18 years old with congenital heart disease (CHD) including 65 patients with cyanotic (C) and 166 with acyanotic (AC) diseases, were surgically treated. There were one operative death (0.6 percent mortality) and three late deaths (1.9%) in 166 patients with AC diseases, whereas there were four operative (6.1%), and four late deaths (6.1%) in 65 patients with C. These patients were followed for 3 to 124 months (the mean of 46.4 +/- 11.9) after the operation. Compared with group AC, group C showed a high rate of early postoperative deaths or late deaths. Group AC comprised patients in their forties (95 patients with ASD and 15 with PDA) and those in their thirties (26 with VSD and 13 with ECD) at the operation. On the contrary, except 5 patients with Ebstein disease, a mean age of patients of group C at the operation lay in their twenties. Surgical outcomes for adult patients of group C still pose much problems compared with AC group in terms of decreased heart function, development of collateral circulatory pathway, and impaired hepatic and renal functions by long lasting hypoxemia. In group C decreased heart function or association of abscess of the brain might be the main cause of postoperative LOS. These findings indicate that early diagnosis, recent advanced operative procedure and appropriate postoperative care can provide symptomatic remission for even adult patients with severe CHD with a low mortality.

[Interleukin-4 (IL-4)]

Helper T cells can be divided into Th1 type cell which produces IL-2 and IFN-gamma and Th2 type cell which produces IL-4, IL-5, and IL-6. In general, cytokine has a pleiotropic action. Furthermore cytokines have redundancy in their action. IL-4 is a major product of Th 2 type cell and is an essential cytokine for IgE production, which is also induced by recently found IL-13. Additionally IL-4 is a key factor for the development of Th2 cell, which produces cytokines responsible for inducing allergic reaction. In this paper, we described the gene regulation, molecular structure and biological action including the anti-tumor activity of IL-4.

Human neuroblastoma growth inhibitory factor (h-NGIF), derived from human astrocytoma conditioned medium, has neurotrophic properties

Investigations on the general characteristics of human astrocytoma cell line NAC-1 revealed neuroblastoma growth inhibitory activity in conditioned medium. Neuroblastoma growth inhibitory factor (NGIF) was partially purified by Econo Q, Econo CM, and Superose 12 column chromatography. The protein is weakly basic with an estimated M(r) of 120,000, possibly having an M(r) 60,000 dimeric structure. NGIF inhibits the growth of human neuroblastoma cell lines but has no effect on morphology nor does it produce any change in the growth of human glioblastoma cell lines. Interestingly, NGIF appears to promote survival and neurite outgrowth of embryonal rat cortical neurons. These neurotrophic properties suggest a role for NGIF in the development of the nervous system.

Exocrine pancreatic ductograms in insulin-dependent diabetes mellitus

OBJECTIVES

To examine the prevalence of abnormal pancreatic ductograms in patients with insulin-dependent diabetes mellitus (IDDM) and to determine the clinical characteristics of those patients.

METHODS

Pancreatic exocrine morphology was studied by endoscopic retrograde pancreatography (ERP) in 43 patients with IDDM, 12 patients with islet cell antibody (ICA)-positive non-insulin-dependent diabetes mellitus (NIDDM), and 22 patients with ICA-negative NIDDM.

RESULTS

ERP revealed a significantly higher prevalence of abnormal pancreatic ducts (dilation and stenosis, tortuosity, obstruction, and intraductal calculi) in the patients with IDDM (17/43, 40%) than in the patients with ICA-negative NIDDM (2/22, 9%, p = 0.018). IDDM patients who slowly progressed to insulin dependency more than 13 months after the onset of diabetes had a higher frequency of abnormal pancreatic ducts (13/22, 59%) than those who needed insulin therapy within 12 months after the onset (4/21, 19%, p = 0.016). There was no difference in duration of diabetes between the two groups. ICA-positive NIDDM patients also had a higher frequency of abnormal pancreatic ducts (7/12, 58%) than ICA-negative NIDDM patients (2/22, 9%, p = 0.0074).

CONCLUSIONS

These results indicate that a high proportion of IDDM patients who have prolonged histories of non-insulin dependency with ICA suffer pancreatic exocrine impairment. A similarity between IDDM with a slowly progressive clinical course and fibrocalculous pancreatic diabetes seen in tropical countries also was suggested.

Effect of chronic renal medullary nitric oxide inhibition on blood pressure

The effects of chronic nitric oxide inhibition in the renal medulla on renal cortical and medullary blood flow, sodium balance, and blood pressure were evaluated in conscious uninephrectomized Sprague-Dawley rats. During a 5-day renal medullary interstitial infusion of the nitric oxide inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 120 micrograms/h) in saline (0.5 ml/min), renal medullary blood flow was selectively decreased by 30% after 2 h and was maintained at that level for the entire infusion. The decrease in medullary blood flow was associated with sodium retention and increased blood pressure. After the cessation of L-NAME infusion, medullary blood flow returned to control, and the sodium balance became negative as blood pressure returned to baseline. These data indicate that renal medullary nitric oxide plays an important role in the regulation of renal blood flow, sodium excretion, and blood pressure.

Chronic exposure to simulated altitude does not increase angiogenic activity in skeletal muscle of rats

In order to examine whether the hypoxia of high altitude increases angiogenic activity in skeletal muscle, six male Wistar rats were subjected to a simulated altitude of about 5,500 m (ambient pressure 380 mmHg) for 3 weeks, and the whole soleus, gastrocnemius, and extensor digitorum longus muscles were collected. As a result, any muscle extracts from high altitude rats did not significantly enhance the capillary growth in an in vitro angiogenesis model compared with those from sea-level rats. This appeared to confirm previous morphological studies that hypobaric-hypoxic environment did not cause the formation of new capillaries in skeletal muscles.

Fermentative production of tryptophan by a stable recombinant strain of Corynebacterium glutamicum with a modified serine-biosynthetic pathway

Introduction of plasmid pKW99, which coexpresses the deregulated 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and tryptophan-biosynthetic enzymes, into tryptophan-producing Corynebacterium glutamicum KY10894 resulted in a marked increase (54%) in yield of tryptophan production (43 g/liter), but incurred two problems. One was a decline in sugar consumption at the late stage of fermentation, and the other the loss of the plasmid in the absence of selective pressure. The retarded sugar assimilation was found to be attributed to the death of cells that arose from the detrimental action of indole, the last intermediate in the tryptophan pathway, accumulated as a by-product. A chain of these events simultaneously disappeared when serine, the other substrate of the final reaction by tryptophan synthase, was added. These results indicated that a limiting supply of serine was the cause of the decline in the sugar consumption. Thus, to increase carbon flux into serine, the gene for 3-phosphoglycerate dehydrogenase (PGD), the first enzyme in the serine pathway, was cloned from wild-type C. glutamicum ATCC 31833 and joined onto pKW99 to generate pKW9901. Strain KY10894 transformed with pKW9901 favorably consumed sugar through fermentation with accumulating little indole. Furthermore, on the basis of the observation that serine in the medium was consumed rapidly by the recombinant cells, we developed a unique plasmid stabilization system composed of KY9218 (a PGD-deficient serine-requiring strain of KY10894) and pKW9901: In its combination, cells lacking the plasmid should not proliferate in the fermentation medium which does not contain serine. Even if selective pressure was not applied, the modified strain KY9218 with pKW9901 stably maintained the plasmid during fermentation and produced 50 g/liter of tryptophan in a 61% increased yield relative to strain KY10894.

Protection against alloxan-induced diabetes by diethyldithiocarbamate and disulfiram in mice

Diethyldithiocarbamate (DEDC, 0.25-2.00 mmol/kg) injected into mice at 0.5 hr prior to alloxan administration dose-dependently protected the mice against the diabetogenic actions of 75 mg/kg alloxan. Disulfiram (DS, 0.50-2.00 mmol/kg), a corresponding disulfide form, also exhibited similar protection. The maximum effect of DEDC was found by dosing at 0.5 hr prior to alloxan, and the effect afforded by DEDC pretreatment persisted up to 3 hr, whereas the effect of DS was exhibited when the compound was given 0.5 hr prior to alloxan. Of the metabolites of DEDC, diethylamine and carbon disulfide had no effect. At 0.5 hr after injection, DEDC alone had a potent increasing ability on blood glucose in a dose-dependent manner, but DS was less potent. Mannoheptulose, an antagonist of glucose action at pancreatic beta-cells, when given 24 min after DEDC and 6 min before alloxan, eliminated the DEDC-induced protection. Fasted mice did not exhibit hyperglycemia at 0.5 hr after DEDC injection, and alloxan given at that time produced diabetes. These findings indicate that DEDC itself protected mice from alloxan-induced diabetes by the indirect mechanism of producing hyperglycemia at the time of alloxan administration. The anti-diabetogenic action of low doses of DS and DEDC, in animals lacking hyperglycemia at the time of alloxan injection, is likely based on a mechanism other than one involving hyperglycemia.

[The importance of dose intensity in preoperative chemotherapy for osteosarcoma--retrospective analysis of a short intensive chemotherapy regimen preoperatively using high-dose methotrexate and cisplatinum]

A retrospective investigation was performed on the significance of dose intensity in preoperative chemotherapy for osteosarcoma. In this paper, we studied 29 patients, who had classical stage II-B osteosarcoma and received preoperative treatment consisting of high dose methotrexate (HD-MTX) and/or cisplatinum (CDDP) between 1985 and 1991. Preoperative dose intensity was calculated in the following two ways. 1. Total dose of MTX and CDDP administered during initial five weeks: MTX (g)/10/m2 + CDDP(mg)/100/m2 2. Dose intensity of MTX and CDDP from initiation of treatment (I) to resumption of postoperative chemotherapy (R): MTX (g)/10/m2 + CDDP (mg)/100/m2 / days from (I) to (R)/ideal period of new regimen (63 days) Continuous disease free survival rate (CDFR) was significantly higher in the group receiving preoperative chemotherapy at higher dose intensity (> 3.0). Supplementary administration of adriamycin (ADR) to CDDP/MTX was not favorable in the preoperative stage, because it put off the following therapy and diminished the dose intensity. Since July 1989, we have tried a short intensive preoperative chemotherapy regimen: weekly two cycles of CDDP 100 mg/m2 intravenously, followed by weekly two cycles of HD-MTX 10g/m2. Surgery was scheduled six weeks after beginning treatment, and postoperative chemotherapy was started three weeks after surgery. Twenty patients have been treated by this regimen to date. All patients remain disease free, and six are CDF beyond 24 months.

Malonofungin: an antifungal aminomalonic acid from Phaeoramularia fusimaculans

In screening for antifungal metabolites, a novel compound, malonofungin, exhibiting growth inhibitory activity against Botrytis cinerea (grey mould), has been isolated from fermentations of Phaeoramularia fusimaculans CBS 616.87. Its structure is established as (E)-(3R,4S,5S)-5-acetoxy-2-amino-2-carboxy-3,4-dihydroxy-14-oxoicos++ +-6-enoic acid, representing an addition to the rare class of naturally occurring aminomalonic acids. 1H NMR data and extensive use of CD spectroscopy have been utilized to establish the absolute stereochemistry of malonofungin. The structural and biological relationship of malonofungin to previously reported fungal metabolites is discussed.

[Usefulness of 3DFT-FISP MR imaging in differential diagnosis of liver tumor]

Dynamic 3-dimensional Fourier transformation (3 DFT)-FISP MR imaging was performed in 30 patients with 49 liver tumors (hepatocellular carcinoma 26, hemangioma 13, cholangiocellular carcinoma 2, metastatic liver tumor 8) to evaluate characteristic enhancement patterns. MR images of 3 DFT-FISP (TR/TE/flip angle/slab thickness/partition/slice thickness, 20 msec/8 msec/30 degree/21-75 mm/7 or 15/3-5 mm) were obtained before, just after (early phase), 1 min after (late phase 1) and 2-4 min after (late phase 2) the administration of 0.1 mmol/kg of Gd-DTPA. Twenty-three of the 26 (88%) hepatocellular carcinomas showed total hyperintense enhancement relative to surrounding liver parenchyma in the early phase, and isointense or total hypointense enhancement in the late phase. Eleven of 13 (85%) hemangiomas showed peripheral hyperintense enhancement in the early phase, and peripheral or total hyperintense enhancement in the late phase. Cholangiocellular carcinomas were enhanced gradually from the early to the late phase. Metastatic liver tumors showed doughnut-like ring enhancement in all 8 lesions in the early phase. We concluded that 3 DFT-FISP dynamic MR imaging was useful in the differential diagnosis of liver tumor.

A1 receptor mediated myocardial infarct size reduction by endogenous adenosine is exerted primarily during ischaemia

OBJECTIVE

The aim was to test the hypothesis that A1 receptor mediated cardioprotection by endogenous adenosine is exerted during ischaemia rather than reperfusion.

METHODS

Anaesthetised open chest rabbits were subjected to 30 min regional ischaemia and 120 min reperfusion, and randomised to one of six groups: group I--saline vehicle (VEH) (n = 12) to allow A1 and A2 adenosine receptor interactions during ischaemia and reperfusion; group II--both A1 and A2 receptors were antagonised during ischaemia and reperfusion with 8-p-sulphophenyltheophylline (SPT) (10 mg.kg-1) (SPTIR, n = 14); groups III and IV--the selective A1 adenosine receptor antagonist 8-(3-noradamantyl)-1,3-dipropylxanthine (KW-3902) was given during ischaemia-reperfusion in low dose (1 mg.kg-1, LA1-IR, n = 11) and higher dose (2 mg.kg-1, HA1-IR, n = 6); group V--KW-3902 (1 mg.kg-1) was given only during reperfusion (A1-R, n = 12); group VI--SPT was given only at reperfusion (SPTR, n = 11).

RESULTS

In in vitro studies, (1) KW-3902 completely inhibited negative inotropic effects of the A1 agonist R(-)N6-(2-phenylisopropyl) adenosine (R-PIA) in catecholamine stimulated papillary muscles, and (2) had no effect on concentration dependent vasorelaxation to adenosine or R-PIA. In in vivo studies, transmural myocardial blood flow in the area at risk (determined using 15 microns radiolabelled microspheres) was reduced by 98% in all groups from 139(SEM 15.8) to 2.7(1.1) ml.min-1 x 100 g-1 (p < 0.001). At 120 min of reperfusion, blood flow in the area of necrosis was significantly less in groups LA1-IR [48.6(6.2)], HA1-IR [36.1(7.1)], SPTIR [35.9(6.4)], and SPTR [25.1(5.4)] compared to groups VEH [69.1(15.8)] and A1-R [77.2(11.8)]. The area at risk (Ar) was equivalent among groups. SPT treatment during ischaemia-reperfusion in the SPTIR group increased the area of necrosis (An, assessed by triphenyltetrazolium chloride) relative to Ar (An/Ar) to 51(1.9)% v 26.0(1.7)% in VEH group. KW-3902 in LA1-IR and HA1-IR during both ischaemia and reperfusion increased An/Ar to 35.2(2.5)% and 35.2(2.1)% of area at risk, respectively, both of which were significantly less than the SPTIR group. With A1 blockade at reperfusion (A1-R), An/Ar was equivalent to that in VEH [27.0(1.9)%], while an infarct size of 46.7(2.1)% was still observed in SPTR.

CONCLUSIONS

While adenosine exerts its predominant modulation of infarct size during reperfusion, the cardioprotection mediated by A1 receptor mechanisms is modest and exerted principally during the ischaemic time period.

Immobilized cells used for detection and analysis

Many kinds of biosensor have now been developed and utilized for various types of analysis including clinical, medical and environmental monitoring, industrial process control, as well as many other applications. The microbial biosensor has advantages, such as longer lifetime and lower cost, over other types of biosensor. Recently, photobacteria and recombinant bacteria have been employed in biosensors both for determining biochemical oxygen demand and for detecting heavy metals and other toxic compounds.

Intracellular signaling activity of synthetic (14R)-, (14S)-, and (14RS)-14-hydroxy-4,14-retro-retinol

14-Hydroxy-4,14-retro-retinol (14-HRR), first isolated from cultures of lymphoblastoid 5/2 and HeLa cells and characterized by NMR, UV, and CD, is a metabolite of retinol which promotes growth of B lymphocytes in culture and activation of T lymphocytes by antigen receptor-mediated signals. It is also produced by various tested cell lines: fibroblasts, leukemia, and Drosophila cells. 14-HRR is the first bioactive retro-retinoid to be discovered and, after retinal and retinoic acid, is the third intracellular messenger molecule derived from retinol. Physical properties and intracellular signaling activities of synthetic (14R)-HRR, (14S)-HRR, and racemic 14-HRR are described. CD spectra indicate that natural 14-HRR isolated previously was a mixture of enantiomers. B-cell survival and T-cell activation assays performed in the optimal range of (7-1.6) x 10(-7) M surprisingly showed that all 14-HRR compounds exhibit similar activity, with the 14R enantiomer exhibiting slightly higher activity in comparison to the 14S enantiomer. However, because of the semiquantitative nature of the assays, the conclusion as to which enantiomer is more active and which is the true ligand for the target receptor must await characterization of this protein.

Unbleachable rhodopsin with an 11-cis-locked eight-membered ring retinal: the visual transduction process

Visual transduction occurs through photorhodopsin, the primary photoproduct of rhodopsin, which relaxes to bathorhodopsin and a series of other intermediates until it reaches the metarhodopsin II stage, upon which the enzymatic cascade leading to vision is activated. Despite advances in areas related to visual transduction, the triggering process itself, a key problem in the chemistry of rhodopsin, has remained unsolved. In order to clarify the extent of involvement of the chromophoric excited state versus the 11-cis to trans isomerization, and as an extension of past studies with 11-cis-locked seven-membered ring rhodopsin (Rh7), 11-cis eight- and nine-membered ring retinal analogs, ret8 and ret9, respectively, have been synthesized. The bulkiness of the tetramethylene bridge in ret8 led to numerous unexpected obstacles in attempts to reconstitute a ret8-containing rhodopsin (Rh8) embedded in lipid bilayer membranes. These obstacles were solved by using methylated rhodopsin which gave MeRh8 containing 11-cis-ret8 as its chromophore. MeRh8 exhibited UV-vis and CD spectra very similar to those of native rhodopsin (Rh); furthermore, the quantum efficiency of photorhodopsin formation was comparable to that of Rh.(ABSTRACT TRUNCATED AT 250 WORDS)