The effect of early burn wound excision on regional gastric blood flow in rats

This study examined the effects of early burn wound excision on gastric blood flow and on morphologic changes in mucosal vessels. Wistar rats were given a 30% total body surface area burn and divided into four groups, consisting of control animals (group 1), animals with burn injury without and with fluid resuscitation (groups 2 and 3, respectively), and animals with both fluid resuscitation and early wound excision (group 4). Gastric mucosal blood flow (GMBF) was measured by the hydrogen gas clearance method up to 24 h post-burn. Morphologic changes in mucosal vessels were examined by scanning electron microscopy (SEM) at 3 and 24 h post-burn. The GMBF sharply decreased in the acute period after the burn. In group 4, however, it recovered to the initial value by 6 h post-burn and there was no significant change throughout the experiment. Morphologically, although the mucosal capillaries revealed some changes such as irregularity in diameter in groups 2-4 at 3 h, most of mucosal capillaries retained their original appearance in group 4 at 24 h post-burn. These result suggest that early excision does not aggravate the state of gastric ischemia.

Peroxynitrite is not a major mediator of endothelial cell injury by activated neutrophils in vitro

OBJECTIVE

Human polymorphonuclear leukocytes (PMN) produce nitric oxide (NO), superoxide (O2.-) and peroxynitrite (ONOO-) upon stimulation. We investigated the role of ONOO- in PMN-induced injury to cultured bovine aortic endothelial cells (BAEC).

METHODS

BAEC were cocultured with phorbol 12-myristate 13-acetate (PMA)-activated human PMN (effector-to-target ratio, 10:1) and injury to BAEC was evaluated at intervals by 51Cr release assay. The levels of NO, O2.-, ONOO- and nitrotyrosine, a reaction product of ONOO-, were also measured, and the influence of NO synthase inhibitors, O2.- and hydroxyl radical scavengers and other effectors was examined.

RESULTS

In BAEC cocultured with PMA-activated PMN, 51Cr release was significantly increased [14.6 +/- 2.2% at 2 h (p < 0.05) and 42.6 +/- 2.7% at 4 h (p < 0.01); control (nonactivated PMN), < 4%]. Superoxide dismutase (100 U/ml) reduced 51Cr release to 4.6 +/- 2.2% at 2 h (p < 0.05). N-Iminoethyl-L-ornithine (L-NIO, 0.1 mM) potentiated 51Cr release (30.6 +/- 3.8% at 2 h, p < 0.01), and the potentiation was eliminated by anti-CD18 monoclonal antibody. The 51Cr release was completely prevented by dimethyl sulfoxide or by deferoxamine. Treatment of PMN with L-NIO inhibited NO generation and increased O2.- production. The nitrotyrosine level did not increase in BAEC cocultured with PMA-activated PMN.

CONCLUSION

NO-derived ONOO- is not a major cytotoxic mediator in BAEC injury by activated PMN. NO may have a cytoprotective effect by inhibiting PMN adherence to endothelial cells.

Mode of action of (1'S,2'R)-9-[[1',2'-bis(hydroxymethyl) cycloprop-1'-yl]methyl]guanine (A-5021) against herpes simplex virus type 1 and type 2 and varicella-zoster virus

The mode of action of (1'S,2'R)-9-([1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl)guanine (A-5021) against herpes simplex virus type 1 (HSV-1), HSV-2, and varicella-zoster virus (VZV) was studied. A-5021 was monophosphorylated at the 2' site by viral thymidine kinases (TKs). The 50% inhibitory values for thymidine phosphorylation of A-5021 by HSV-1 TK and HSV-2 TK were comparable to those for penciclovir (PCV) and lower than those for acyclovir (ACV). Of these three agents, A-5021 inhibited VZV TK most efficiently. A-5021 was phosphorylated to a mono-, di-, and triphosphate in MRC-5 cells infected with HSV-1, HSV-2, and VZV. A-5021 triphosphate accumulated more than ACV triphosphate but less than PCV triphosphate in MRC-5 cells infected with HSV-1 or VZV, whereas HSV-2-infected MRC-5 cells had comparable levels of A-5021 and ACV triphosphates. The intracellular half-life of A-5021 triphosphate was considerably longer than that of ACV triphosphate and shorter than that of PCV triphosphate. A-5021 triphosphate competitively inhibited HSV DNA polymerases with respect to dGTP. Inhibition was strongest with ACV triphosphate, followed by A-5021 triphosphate and then (R,S)-PCV triphosphate. A DNA chain elongation experiment revealed that A-5021 triphosphate was incorporated into DNA instead of dGTP and terminated elongation, although limited chain extension was observed. Thus, the strong antiviral activity of A-5021 appears to depend on a more rapid and stable accumulation of its triphosphate in infected cells than that of ACV and on stronger inhibition of viral DNA polymerase by its triphosphate than that of PCV.

Production of a mixture of antimicrobial organic acids from lactose by co-culture of Bifidobacterium longum and Propionibacterium freudenreichii

The antimicrobial activities of standard solutions of three organic acids (lactic, acetic, and propionic acids) were compared using Micrococcus luteus, Pseudomonas sp. and Staphylococcus aureus as test microorganisms. At the same concentrations of the undissociated form, the antimicrobial activities of acetic and propionic acids were higher than that of lactic acid, irrespective of test microorganisms. In a single cultivation of Bifidobacterium longum, a mixture of lactic (17 g/l) and acetic (20 g/l) acids was produced from 50 g/l lactose and its antimicrobial activities against M. luteus, Pseudomonas sp., and S. aureus correspond to that of 32, 19, and 25 g/l of acetic acid, respectively. To increase the total antimicrobial activity, a co-culture of B. longum and Propionibacterium freudenreichii, in which lactic acid produced once from lactose by B. longum was converted to acetic and propionic acids by P. freudenreichii, was done using TPY medium containing commercially available peptones as a nitrogen source. By the sequential conversion of lactose using the two microorganisms, the culture supernatant containing a mixture of acetic (27 g/l) and propionic (13 g/l) acids without lactic acid was produced. The antimicrobial activities of the mixture against M. luteus, Pseudomonas sp., and S. aureus were 35, 30, and 26 g/l as a concentration of acetic acid, respectively, higher than that obtained in the cultivation of B. longum alone. When the medium containing an enzymatic hydrolyzate of whey proteins with a protease was used in the co-culture of B. longum and P. freudenreichii, the culture supernatant containing the mixture of organic acids was also obtained in the same manner as the co-culture using TPY medium and the activities were 43, 29, and 29 g/l as a concentration of acetic acid for M. luteus, Pseudomonas sp. and S. aureus, respectively.

Separation of lac dye components by high-speed counter-current chromatography

High-speed counter-current chromatography has been successfully applied to the separation of the lac dye components. A 25-mg quantity of the sample was separated using a two-phase solvent system composed of tert.-butyl methyl ether-n-butanol-acetonitrile-water (2:2:1:5). The fractions were analyzed by high-performance liquid chromatography and electrospray tandem mass spectrometry. The separation yielded 2.6 mg of 97.2% pure laccaic acid C, 9.5 mg of 98.1% pure laccaic acid A, 3.6 mg of 98.2% pure laccaic acid B, and 0.5 mg of a 95.0% pure anthraquinonedicarboxylic acid with a molecular mass of 360.

Simultaneous determination of beta-lactam antibiotics in milk by ion-pair liquid chromatography

A simple and rapid ion-pairing liquid chromatographic method was developed for the simultaneous determination of five penicillins (PCs), ampicillin (AB-PC), benzylpenicillin (PC-G), Dicloxacillin (MDI-PC) and nafcillin (NF-PC) in milk. These PCs are most frequently used for the treatment of mastitis of cows. These antibiotics were extracted with acetonitrile from milk and cleaned up by solid-phase extraction with a C18 cartridge. PCs were separated on a Kaseisorb LC ODS-300-5 column with a mobile phase (1 ml/min) of acetonitrile-methanol-0.05 M potassium dihydrogenphosphate (20:10:80, v/v/v) mixture containing 5 mM of sodium 1-decanesulfonate adjusted to pH 3.5 and UV detection at 210 nm. The average recoveries of five PCs from milk fortified at 0.5 and 1.0 micrograms/ml (n = 5) were 79.8-89.4% with relative standard deviations ranging from 2.7 to 7.2% The detection limit of PCs in milk were 0.03-0.05 microgram/ml.

Simultaneous determination of five macrolide antibiotics in meat by high-performance liquid chromatography

A simple and rapid method using high-performance liquid chromatography (HPLC) for the simultaneous determination of five macrolides (josamycin, kitasamycin, mirosamicin, spiramycin and tylosin) in meat has been developed. The drugs were extracted with 0.3% metaphosphoric acid-methanol (7:3, v/v), and the extracts were cleaned up on a Bond Elut SCX (500 mg) cartridge. The HPLC separation was performed on a Puresil 5C18 column (150 x 4.6 mm I.D.) with a gradient system of 0.025 M phosphate buffer (pH 2.5)-acetonitrile as the mobile phase at a flow-rate of 1.0 ml/min. The drugs were detected at 232 mn for josamycin, kitasamycin, mirosamicin and spiramycin, and 287 mn for tylosin. The calibration graphs were rectilinear from 2.5 to 100 ng for each drug. The recoveries at the level of 1.0 microgram/g were 70.8-90.4%, and detection limits were 0.05 microgram/g for each drug.

Antiherpesvirus activities of (1'S,2'R)-9-[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanine (A-5021) in cell culture

Antiherpetic activity of (1'S,2'R)-9-([1',2'-bis(hydroxymethyl)cycloprop-1'yl]methyl)guanine (A-5021) was compared with those of acyclovir (ACV) and penciclovir (PCV) in cell cultures. In a plaque reduction assay using a selection of human cells, A-5021 showed the most potent activity in all cells. Against clinical isolates of herpes simplex virus type 1 (HSV-1, n = 5) and type 2 (HSV-2, n = 6), mean 50% inhibitory concentrations (IC50s) for A-5021 were 0.013 and 0.15 microgram/ml, respectively, in MRC-5 cells. Corresponding IC50s for ACV were 0.22 and 0.30 microgram/ml, and those for PCV were 0.84 and 1.5 micrograms/ml, respectively. Against clinical isolates of varicella-zoster virus (VZV, n = 5), mean IC50s for A-5021, ACV, and PCV were 0.77, 5.2, and 14 micrograms/ml, respectively, in human embryonic lung (HEL) cells. A-5021 showed considerably more prolonged antiviral activity than ACV when infected cells were treated for a short time. The selectivity index, the ratio of 50% cytotoxic concentration to IC50, of A-5021 was superior to those of ACV and PCV for HSV-1 and almost comparable for HSV-2 and VZV. In a growth inhibition assay of murine granulocyte-macrophage progenitor cells, A-5021 showed the least inhibitory effect of the three compounds. These results show that A-5021 is a potent and selective antiviral agent against HSV-1, HSV-2, and VZV.

Occurrence of Erysipelothrix spp. in broiler chickens at an abattoir

From September 1995 to August 1996, 750 chickens from 66 farms sent to an abattoir in Nagano Prefecture, Japan, were examined for the presence of Erysipelothrix spp. Erysipelothrix spp. were isolated from 118 (15.7%) of 750 skin samples, 27 (7.3%) of 372 hypoderm samples, 12 (1.9%) of 630 throat samples, 106 (59.2%) of 179 feather samples, and none of 257 spleen samples. Of 66 farms, 55 farms (83.3%) sent Erysipelothrix-positive chickens and 11 farms (16.7%) only negative ones. Of 297 Erysipelothrix isolates, 273 isolates were identified as Erysipelothrix rhusiopathiae and 24 as Erysipelothrix tonsillarum. E. rhusiopathiae isolates were serotyped into nine different serovars. Of the 273 E. rhusiopathiae isolates, 33 (11.1%) were serotyped to serovar 6; 22 (7.4%) were serovar 5; 19 (6.4%) were serovar 2; 15 (5.1%) were serovar 8; 2 (0.7%) were serovar 21; 4 each (1.3% each) were serovars 1b, 9, 12, and 19; and 178 (59.9%) were untypeable. Of 24 E. tonsillarum isolates, 15 (5.1%) were serotyped to serovar 3, and 9 (3.0%) were serovar 7. These findings indicate that chickens seem to be a potential reservoir of Erysipelothrix spp. in nature and to be a source of human Erysipelothrix infection.

Detection and quantification of soluble intercellular adhesion molecule-1 (sICAM-1) in the serum and urine of patients with bladder cancer

BACKGROUND

A possible role for intercellular adhesion molecules in tumor progression and metastasis has been strongly suggested. To investigate the effect of soluble intercellular adhesion molecule-1 (sICAM-1) on bladder cancer, sICAM-1 serum and urinary concentrations were measured in patients with superficial or invasive bladder cancer and in patients with prostatic hypertrophy.

METHODS

Serum and urine samples were obtained from 26 patients with transitional cell carcinoma of the bladder (mean age, 66.8 years) and 14 patients with benign prostatic hypertrophy (BPH; mean age, 70.5 years). Fifteen healthy volunteers served as control patients. Samples were collected before surgery and 5 days after surgery. The serum and urinary slCAM-1 levels were measured by an ELISA.

RESULTS

The preoperative serum concentration of sICAM-1 was significantly higher in patients with invasive bladder cancer (351.8+/-158.0 ng/mL) than in the healthy controls (233.1+/-96.1 ng/mL; P< 0.05) or BPH patients (224.7+/-80.5 ng/mL; P< 0.05). In addition, serum sICAM-1 levels were significantly higher in patients with tumors greater than 3 cm in size (412.7+/-147.6 ng/mL) than in patients with smaller tumors (246.6+/-101.2 ng/mL; P<0.05). Urinary sICAM-1 levels in patients with invasive bladder cancer were also significantly higher than in the patients with superficial cancer prior to surgery.

CONCLUSION

Our results suggested that sICAM-1 may play an important role in the progression of bladder cancer, and that elevated serum sICAM-1 levels may be related to tumor size.

An unusual course of progressive multifocal leukoencephalopathy in a patient with idiopathic CD4+ T lymphocytopenia

A case is reported of idiopathic CD4+T lymphocytopenia with progressive multifocal leukoencephalopathy and cervical lymph node tuberculosis. A 57 year old Japanese man presented with cervical lymphadenopathy and progressive neurological deficits, and six months later he developed akinetic mutism. He had a persistent severely depressed number of circulating CD4+T lymphocytes in the absence of human immunodeficiency virus infection. T1 weighted MRI showed a diffuse decreased signal intensity limited to the white matter without mass effect. A brain biopsy specimen had a morphology similar to that of progressive multifocal leukoencephalopathy. Polyomavirus antigen was detected in the brain lesion, and viral DNA was identified in nucleated blood cells and urine. Unusually this serious medical condition has lasted for more than three years without remission. To our knowledge this is the first patient with CD4+T lymphocytopenia with progressive multifocal leukoencephalopathy, suggesting that similar opportunistic infections should be considered even in previously normal people.

Regulatory effects of heat on normal human melanocyte growth and melanogenesis: comparative study with UVB

Although energy-rich ultraviolet B (UVB) is considered to be primarily responsible for most of the effects associated with solar radiation, small energy recorded as heat appears to contribute to the biologic effects of solar radiation on the skin. We compared the effects of heat and UVB on normal human melanocyte functions. In monolayer culture the following was found. (i) Heat-treated melanocytes showed an increased dendricity and exhibited a larger cell body compared with nontreated melanocytes. (ii) After multiple treatments with UVB (20 mJ per cm2, 312 nm) or heat (42 degrees C for 1 h) for 3 d, melanocytes had a lower survival than nontreated melanocytes, but they resumed proliferation within 6 d in the same manner as seen in control. (iii) The expression levels of cell cycle regulators, p53 and p21 proteins, were increased after multiple treatments with UVB or heat. (iv) The tyrosinase (dopa-oxidase) activity per cell was increased after the multiple treatments with UVB or heat. (v) The number of dopa-positive melanocytes in coculture with keratinocytes in epithelial sheets was greatly increased by UVB or heat treatments. (vi) Similarly, the increased number of tyrosinase-related protein 1 positive melanocytes was seen in skin equivalents after UVB (100 mJ per cm2) or heat (42 degrees C for 1 h) treatments for 7 d. These results suggest that heat shares significant biologic activities with UVB in melanocyte functions. These results could be considered as one of the protective or adaptive responses of the skin pigmentary system to the environment.

Role of nitric oxide and peroxynitrite in the cytokine-induced sustained myocardial dysfunction in dogs in vivo

Studies in vitro suggested that inflammatory cytokines could cause myocardial dysfunction. However, the detailed mechanism for the cytokine-induced myocardial dysfunction in vivo remains to be examined. We thus examined this point in our new canine model in vivo, in which microspheres with and without IL-1beta were injected into the left main coronary artery. Left ventricular ejection fraction (LVEF) was evaluated by echocardiography for 1 wk. Immediately after the microsphere injection, LVEF decreased to approximately 30% in both groups. While LVEF rapidly normalized in 2 d in the control group, it was markedly impaired in the IL-1beta group even at day 7. Pretreatment with dexamethasone or with aminoguanidine, an inhibitor of inducible nitric oxide synthase, prevented the IL-1beta-induced myocardial dysfunction. Nitrotyrosine concentration, an in vivo marker of the peroxynitrite production by nitric oxide and superoxide anion, was significantly higher in the myocardium of the IL-1beta group than in that of the control group or the group cotreated with dexamethasone or aminoguanidine. There was an inverse linear relationship between myocardial nitrotyrosine concentrations and LVEF. These results indicate that IL-1beta induces sustained myocardial dysfunction in vivo and that nitric oxide produced by inducible nitric oxide synthase and the resultant formation of peroxynitrite are substantially involved in the pathogenesis of the cytokine-induced sustained myocardial dysfunction in vivo.

Increased nitric oxide in nasal lavage fluid and nitrotyrosine formation in nasal mucosa--indices for severe perennial nasal allergy

BACKGROUND

The nose contributes the large amount of nitric oxide (NO) to exhaled air. NO is a mediator of vasodilation and yields peroxynitrite (ONOO-) by reacting with superoxide (O2-). ONOO attacks tyrosine residues to form nitrotyrosine.

OBJECTIVE

The aim of this study was to examine the pathophysiological role of NO in nasal mucosa in patients with perennial nasal allergy.

METHODS

We measured nitrite and nitrate (NO2-/NO3-) and 3',5'-guanosine monophosphate (cyclic GMP) in nasal lavage fluid, and also measured haemoglobin concentration in nasal mucosa as an indicator of blood volume in the patients and healthy volunteers. The deleterious role of NO was also investigated by measuring nitrotyrosine in nasal mucosa.

RESULTS

The NO2-/NO3- concentration in the nasal lavage fluid was 39.5+/-2.8 microM in healthy volunteers (n=40), 42.4+/-3.0 microM in patients with mild allergy (mild group, n=32), and 88.7+/-6.6 microM in patients with severe allergy (severe group, n=61). In the patients whose symptoms were improved with treatment, NO2-/NO3- levels decreased to 45.7+/-10.4 microM. The concentration of cyclic GMP in nasal lavage fluid was higher in the severe group than in the healthy volunteers. The mucosal haemoglobin index was 88+/-4 in the healthy volunteers, 67+/-4 in the mild group, and 53+/-2 in the severe group. The formation of nitrotyrosine was expressed 0.58+/-10% to total tyrosine in the severe group (n=11), but was not found in non-allergy patients (n=9).

CONCLUSIONS

The production of NO was increased in patients with perennial nasal allergy, but the blood flow in the nasal mucosa of patients was reduced. Nitrotyrosine formation suggests that there is a process of ONOO(-)-induced damage in mucosa of patients with the perennial nasal allergy and this damage may limit the dilatation of blood vessels, despite the presence of excessive NO.

Complete sequence and gene organization of the genome of a hyper-thermophilic archaebacterium, Pyrococcus horikoshii OT3

The complete sequence of the genome of a hyper-thermophilic archaebacterium, Pyrococcus horikoshii OT3, has been determined by assembling the sequences of the physical map-based contigs of fosmid clones and of long polymerase chain reaction (PCR) products which were used for gap-filling. The entire length of the genome was 1,738,505 bp. The authenticity of the entire genome sequence was supported by restriction analysis of long PCR products, which were directly amplified from the genomic DNA. As the potential protein-coding regions, a total of 2061 open reading frames (ORFs) were assigned, and by similarity search against public databases, 406 (19.7%) were related to genes with putative function and 453 (22.0%) to the sequences registered but with unknown function. The remaining 1202 ORFs (58.3%) did not show any significant similarity to the sequences in the databases. Sequence comparison among the assigned ORFs in the genome provided evidence that a considerable number of ORFs were generated by sequence duplication. By similarity search, 11 ORFs were assumed to contain the intein elements. The RNA genes identified were a single 16S-23S rRNA operon, two 5S rRNA genes and 46 tRNA genes including two with the intron structure. All the assigned ORFs and RNA coding regions occupied 91.25% of the whole genome. The data presented in this paper are available on the internet at http:@www.nite.go.jp.

Characterizations of natural and induced polyhedrin gene mutants of Bombyx mori cytoplasmic polyhedrosis viruses

Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) polyhedrin gene from natural mutant strain B, B2 and P was cloned and the amino acid sequence was compared with that of wild-type virus (strain H). Chimeric polyhedrin genes (8 types) containing only one site of mutation within the amino acid sequence were also constructed. Fifteen types of polyhedrin genes were introduced into a baculovirus expression vector and hexahedral, acicular, pyramidal, or amorphous polyhedra were formed in infected cells. These results demonstrated that the shape of polyhedra as well as the crystallization pattern of the polyhedrin could be changed by mutations at respectively N-terminal and C-terminal regions of BmCPV polyhedrin gene.

UV-radiation-specific p53 mutation frequency in normal skin as a predictor of risk of basal cell carcinoma

BACKGROUND

A strong association has been found between skin cancer and exposure to UV radiation. The p53 tumor suppressor gene (also known as TP53), which is frequently mutated in human cancers, is believed to be an early target in UV radiation-associated skin carcinogenesis. We have previously developed a sensitive, polymerase chain reaction-based method capable of detecting and quantifying a UV radiation-specific mutation in the p53 gene (codons 247 and 248: AAC CGG --> AAT TGG) in normal skin. We have used this method to examine whether UV radiation-specific mutation frequency is associated with risk of basal cell carcinoma (BCC) and with sun exposure.

METHODS

This case-control study in Australia involved 53 case subjects with BCC and 75 control subjects. DNA was isolated from normal skin (mirror-image anatomic site to the cancer site for case subjects and a randomly selected site for control subjects) and assayed for p53 mutation. Relationships between p53 mutation frequency and risk of BCC, sun sensitivity, or sun exposure were estimated by use of odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Case subjects were more likely to have a p53 mutation than control subjects (OR = 3.1; 95% CI = 1.3-7.1). In addition, the odds of BCC increased monotonically with increasing frequency of p53 mutation. No statistically significant associations could be demonstrated between p53 mutation frequency and age, sex, sensitivity to the sun, pigmentary characteristics, total lifetime sun exposure, or sun exposure to the biopsy site.

CONCLUSIONS

Our results indicate that tandem CC --> TT mutations involving codons 247 and 248 of the p53 gene are associated with an increased risk of BCC but cannot be used as an accurate measure of total UV-radiation exposure.

Determination of l-menthol in pharmaceutical products by high performance liquid chromatography with polarized photometric detection

A simple analytical method for l-menthol by high-performance liquid chromatography with a polarized photometric detector was established. The polarized photometric detector was constructed with two polarizers mounted on both sides of the flow cell in a conventional photometric detector and can be easily used for the detection of optically active compound, such as l-menthol. This study was conducted with a newly developed split-cell assembly in order to increase the sensitivity. The characteristic of this method is the ability to determine optically active compounds selectively among the other coexisting materials and the pretreatment of the sample can be very simple or not required at all. The detection of l-menthol by this method is 0.5 microgram. A good agreement was shown between another commonly used GC method and the method described in this paper.

Methylmercury inhibits gap junctional intercellular communication in primary cultures of rat proximal tubular cells

Methylmercury (MeHg) causes renal injury in addition to central and peripheral neuropathy. To clarify the mechanism of nephrotoxicity by MeHg, we investigated the effect of this compound on intercellular communication through gap junction channels in primary cultures of rat renal proximal tubular cells. Twenty minutes after exposure to 30 microM MeHg, gap junctional intercellular communication (GJIC), which was assessed by dye coupling, was markedly inhibited before appearance of cytotoxicity. When the medium containing MeHg was exchanged with MeHg-free medium, dye coupling recovered abruptly. However, the dye-coupling was abolished again 30 min after replacement with control medium, and the cells were damaged. Intracellular calcium concentration, [Ca2+]i, which modulates the function of gap junctions, significantly increased following exposure of the cells to 30 microM MeHg and returned to control level following replacement with MeHg-free medium. These results suggest that the inhibiting effect of MeHg on GJIC is related to the change in [Ca2+]i, and may be involved in the pathogenesis of renal dysfunction.

Inhibition of nitric oxide synthesis aggravates myocardial ischemia in hemorrhagic shock in constant pressure model

In hemorrhagic shock (HS), nitric oxide synthase (NOS) inhibitor is known to increase blood pressure and prolong survival time. On the other hand, NOS inhibitor decreases coronary flow and worsens myocardial ischemia. Therefore, we hypothesized that the beneficial effect of NOS inhibitor is attributable to the increased coronary perfusion pressure and that it outcompetes the coronary vasodilating effects of nitric oxide. To investigate the direct effect of NOS inhibitor on the regulation of coronary circulation and the induction of myocardial ischemia in HS, we used a canine model at a constant aortic pressure of 40 mmHg with an aortic reservoir. In seven dogs, intravenous administration of Nomega-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg) at 10 min after induction of HS increased both systemic and coronary vascular resistances and further increased the serum catecholamine concentration at 10 min after L-NAME. In another 14 dogs, the beating hearts were rapidly cross-sectioned (120 ms) and freeze clamped (-190 degrees C) by a specially developed sampling device after 10 min of HS. Transmurally distributed myocardial ischemia was visualized by the enhanced reduced nicotinamide adenine dinucleotide fluorescence, which was significantly increased with L-NAME (n=7). Chemical analysis revealed a decrease in the myocardial ATP concentration with L-NAME in the subendocardial ischemic region in HS. In conclusion, with the use of an aortic reservoir to keep the aortic pressure constant in HS, NOS blockade significantly worsened myocardial ischemia by decreasing coronary flow and augmenting the serum catecholamine concentration.

[Study on urinary levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha in patients with renal cell carcinoma]

We examined the preoperative and postoperative, urinary levels of the cytokines, interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in 14 patients with renal cell carcinoma (RCC), and 9 patients who underwent nephrectomy as donors (controls). Although urinary IL-1 beta was measurable in every subject, both IL-6 and TNF-alpha were undetectable in 12 of the 14 patients. None of the urinary cytokines showed levels significantly different from the controls preoperatively. Urinary levels of IL-1 beta showed no correlation with clinical stage or histological grade. Only urinary IL-1 beta was significantly elevated after nephrectomy, when compared with the controls (P < 0.05). However, urinary IL-1 beta showed no correlation with operative blood loss or postoperative infection. These findings suggest that measurement of urinary cytokines is not useful for diagnosis or monitoring of therapy in RCC patients.

Peroxynitrite formation in focal cerebral ischemia-reperfusion in rats occurs predominantly in the peri-infarct region

Peroxynitrite (ONOO-) exhibits potent neurotoxicity and plays an important role in neuronal death, but no evidence shows that it is formed in the brain during ischemia or subsequent reperfusion. To detect the formation of ONOO-, we used a hydrolysis/HPLC procedure to measure the formation of 3-nitro-L-tyrosine (NO2-Tyr), which is considered to reflect attack of ONOO- on L-tyrosine residues of cellular components in the brain. Focal ischemia was produced by occluding the right common carotid and right middle cerebral arteries for 2 hours, and the ischemic area was reperfused by reopening the middle cerebral artery. After 2 hours of ischemia, the values of the ratio of NO2-Tyr to L-tyrosine were 0% +/- 0%, 0.42% +/- 0.13% and 0.29% +/- 0.10% in the noninfarct, periinfarct, and core-of-infarct regions, respectively. After 3 hours of reperfusion following 2 hours of ischemia, the ratio in the periinfarct region reached 0.89 +/- 0.22%, which was significantly higher than that in the core-of-infarct region (0.35 +/- 0.09%). The NO2-Tyr was not detected in 50 mg/kg of N-monomethyl-L-arginine-treated or sham-operated rats. Regional CBF in the periinfarct region decreased to 30.8 +/- 15.9 mL/100 g/min during occlusion, but recovered more rapidly than did that in the core-of-infarct region.