Induction of cyclooxygenase 2 in gastric mucosal lesions and its inhibition by the specific antagonist delays healing in mice

BACKGROUND & AIMS

The role of two forms of cyclooxygenase (COX-1 and COX-2) in gastric mucosal lesions is not well understood. The regulation of both forms of COX and the effect of COX-2 on the repair process of gastric mucosal lesions in mice were investigated.

METHODS

Gastric mucosal erosions and ulcers were induced experimentally in mice. The level of COX messenger RNA (mRNA) was determined by reverse-transcription polymerase chain reaction. COX proteins were detected by Western blot analysis, and COX activity was determined in the presence or absence of NS-398, a specific COX-2 antagonist. The effects of long-term administration of NS-398 on gastric ulcers were examined.

RESULTS

COX-2 mRNA levels were not detected in control conditions but were high during the acute stages of gastric erosions and ulcers. COX-2 protein was detected 5 days after ulcer induction but not in control mice. Gastric ulceration was not associated with a change in COX-1 mRNA and protein levels. Administration of NS-398 to mice with ulcers at acute stages impaired the healing of ulcers.

CONCLUSIONS

High levels of COX-2 mRNA and protein during the acute stages of gastric mucosal lesions may be involved in the repair process of these lesions in mice.

Effects of sucralfate on acute gastric mucosal injury and gastric ulcer induced by ischemia-reperfusion in rats

We have revealed that acute gastric mucosal injury induced by a single ischemia-reperfusion (I-R) treatment develops into an ulcerative lesion within a few days. In the present studies, we examined the effects of oral administration of sucralfate on gastric damage induced by I-R. Sucralfate (1-100 mg/kg, 15 min before I-R) significantly reduced the total erosion area observed immediately after I-R. A high dose of sucralfate (30-100 mg/kg) inhibited the increase in the thiobarbituric acid-reactive substances, an index of lipid peroxidation, induced by I-R, although a low dose of it failed. When sucralfate (30 mg/kg, once a day) was orally administered after I-R, it prevented mucosal damage from developing into gastric ulcers: the total area of the ulcers was significantly reduced compared to that without sucralfate administration 72 h after I-R. High concentrations of sucralfate (3-10 mg/ml) reduced the superoxide radicals generated by leukocytes or xanthine-xanthine oxidase, and protected erythrocyte membrane ghosts against lipid peroxidation induced by hydrogen peroxide and Fe2+ in vitro. These results indicate that sucralfate may prohibit both the generation of acute gastric mucosal injury and its progression to ulcer induced by I-R, probably due to a cytoprotective action on the mucosal surface. However, the protective mechanism may involve an inhibitory action on superoxide and hydroxyl radicals at high doses.

Intraischemic hypothermia during pretreatment with sublethal ischemia reduces the induction of ischemic tolerance in the gerbil hippocampus

We examined whether mild brain hypothermia during pretreatment with sublethal 2-min ischemia affected the tolerance to subsequent lethal 5-min ischemia. The neuronal densities in the hippocampal CA1 sector of gerbils preconditioned at mild brain hypothermia (32% of normal) were significantly lower than those in gerbils preconditioned at brain normothermia (70% of normal). 72-kDa heat-shock protein immunoreactivity in the CA1 sector preconditioned at mild hypothermia was reduced. These results suggests that mild brain hypothermia during pretreatment with sublethal ischemia reduces the tolerance to subsequent lethal ischemia.

Quantitative analysis of cyclooxygenase-2 gene expression on acute gastric injury induced by ischemia-reperfusion in rats

The rat model of acute gastric damage induced by ischemia-reperfusion (I-R) has been used to evaluate the protective effect of various drugs on gastric injury. However, the quantitative expression state of cyclooxygenase-2 (COX-2), a protein which induces cytoprotective prostaglandins during inflammation, is still unknown in acute gastric injury induced by I-R. Therefore, we have quantitatively investigated the level of expression of COX-2 mRNA in injured gastric tissue of this model using the reverse transcription-competitive polymerase chain reaction method. The mRNA for COX-2 was expressed at low or undetectable levels in the normal gastric tissues in control rats, which were fasted for 18 hrs without I-R. The mRNA levels of COX-2 in injured gastric tissues were higher than those of control tissues between 6 hrs and 48 hrs after I-R. The maximum expression of COX-2 mRNA was recorded at 24 hrs (approximately a 200-fold increase). The expression state of COX-2, which has been ascertained in this study, should be useful in evaluating the effect of various drugs on the expression of COX-2 in acute gastric damage.

Frozen-section-guided breast-conserving surgery: implications of diagnosis by frozen section as a guide to determining the extent of resection

This study was conducted to analyze retrospectively the results of performing sector resection on 56 breasts in 54 patients with breast cancer. The glands were resected with a 2-cm tumor-free margin on both lateral sides and the distal side, and with more than a 3-cm tumor-free margin on the nipple side. The frequency of positive resection margins for the cancer cells was 7/56 (12.5%) on the nipple side and 12/46 (26.1%) on the lateral sides, with an overall frequency of 15/56 (26.8%). There were positive resected margins for cancer cells on both the nipple and lateral sides in 4/46 patients (9%). Assuming the equivocal margins were positive for cancer cells, an accurate diagnosis by frozen section examination was made in 51 of the 56 operations (91.1%). Additional resection of the margins was performed in all 20 cases of a positive resected margin for cancer cells according to the diagnosis by frozen section. Thereafter, the resected margins became negative in 13 cases (65%), but remained positive in 7 cases (35%). These results show that performing diagnosis by frozen section of the surgical margins is an effective guide to resecting tumors adequately.

Inhibition by cigarette smoke of lipid peroxidation-induced neurotransmitter release

Effects of water-soluble substance in cigarette smoke on neurotransmitter release were investigated using nerve terminals (synaptosomes) prepared from rat cerebral cortex. 2,2'-Azobis (2-amidinopropane) dihydrochloride (ABAP), a peroxyl radical-generator, enhanced the depolarization-evoked release of glutamate and aspartate from synaptosomes with concomitant increase in thiobarbituric acid-reactive substances (TBA-RS) levels in membrane lipids of synaptosomes. The trapped smoke-substance attenuated the lipid peroxidation-enhanced release of excitatory amino acids during the depolarization with reduction in TBA-RS, although it failed to affect the basal release of neurotransmitters. These data suggest that cigarette smoke may possess antioxidant properties to reduce oxidation-induced enhancement of transmitter release from nerve terminals.

SHP-2 is involved in neurotrophin signaling

To investigate the involvement of SHP-2 in the signal transduction pathway stimulated by neurotrophins, the association of SHP-2 with components of the pathway was examined. Following NGF stimulation of PC12 cells, SHP-2 was found to be associated with the p85 subunit of PI3-kinase and the Shc proteins. In retinoic acid-differentiated SH-SY5Y cells and primary cultures of rat cortical neurons, BDNF treatment similarly caused the association of SHP-2 with p85. In addition, a tyrosine-phosphorylated protein, which is probably TrkB, was coimmunoprecipitated with SHP-2 in both cultures. These results show that SHP-2 becomes associated with signaling proteins after treatment with neurotrophins and suggest that SHP-2 plays a fundamental role in neurotrophin signaling.

Changes in levels of mRNAs of transforming growth factor (TGF)-beta1, -beta2, -beta3, TGF-beta type II receptor and sulfated glycoprotein-2 during apoptosis of mouse uterine epithelium

To examine the roles played by transforming growth factors (TGF)-beta1, -beta2, -beta3, and TGF-beta type II receptors in the induction of apoptosis in the mouse uterine epithelium after estrogen deprivation, we investigated the expression of their mRNAs and the mRNA of sulfated glycoprotein-2 (SGP-2). Pellets containing 100 microg estradiol-17beta (E2) were implanted into ovariectomized mice and removed four days later. Apoptotic indices (percentage of apoptotic cells) of both luminal and glandular epithelia increased after E2 pellets were removed, but administration of progesterone (P), 5alpha-dihydrotestosterone (DHT), or continued implantation of E2 pellets suppressed this increase. Levels of mRNAs of TGF-beta1, -beta2, and -beta3, and SGP-2 did not increase after estrogen deprivation. However, estrogen deprivation caused a gradual increase in the level of TGF-beta type II receptor mRNA, and its level increased about six-fold six days later. Moreover, E2, P, and DHT markedly decreased the level of TGF-beta type II receptor mRNA. In situ hybridization demonstrated that mRNAs of TGF-beta1, -beta2, -beta3 and TGF-beta type II receptor were localized to the epithelium. Exogenous administration of TGF-beta1 into the uterine stroma induced apoptosis in the epithelium, a finding that suggests that signals produced by TGF-betas can induce apoptosis. Therefore, the present results suggest that increased sensitivity of uterine epithelial cells to TGF-betas, as demonstrated by an increase in TGF-beta type II receptor mRNA, is involved in the induction of apoptosis after estrogen deprivation, although signals produced by TGF-betas do not appear sufficient to induce apoptosis.

Repeated hyperbaric oxygen induces ischemic tolerance in gerbil hippocampus

Hyperbaric oxygen (HBO; 100% oxygen at 2 atmospheres absolute) was administered for 1 h to male Mongolian gerbils either for a single session or every other day for five sessions. Two days after HBO pretreatment, the gerbils were subjected to 5 min of forebrain ischemia by occlusion of both common carotid arteries under anesthesia. Seven days after recirculation, neuronal density per 1-mm length of the CA1 sector in the hippocampus was significantly better preserved in the five-session HBO pretreatment group (n = 10: 175.7 (47.8/mm, 54.9% of normal) than in the ischemic control group (n = 10: 26.2 (11.6/mm, 8.0% of normal) and in the single-session HBO pretreatment group (n = 7: 37.3 (21.7/mm, 11.4% of normal). Immunohistochemical staining for the 72-kDa heat-shock protein (HSP-72) in the CA1 sector performed 2 days following pretreatment revealed that the five-session HBO pretreatment increased the amount of HSP-72 present compared with that in the ischemic control group and in the single HBO pretreatment group. These results suggest that tolerance against ischemic neuronal damage was induced by repeated HBO pretreatment, which is thought to occur through the induction of HSP-72 synthesis.

Effects of cigarette smoke on nitric oxide-induced increase in cyclic GMP in nerve terminals of rat cerebral cortex

Since nitric oxide (NO) has been widely accepted as a novel neuromodulator, which activates soluble forms of guanylate cyclase to increase in guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels, the effect of water-soluble substance in cigarette smoke on cyclic GMP levels were investigated using nerve terminals prepared from rat cerebral cortex. Although the smoke-substance itself failed to affect cyclic GMP levels in the synaptosomes, the smoke-substance significantly inhibited the increases in cyclic GMP levels induced by NO donors. The blocking effect of the smoke-substance was inhibited by concomitant incubation with superoxide dismutase, but not with mannitol. In addition, the effect of smoke-substance was mimicked by products of the xanthine/xanthine oxidase system, but not by nicotine. The effect of smoke-substance was preserved at least 7 days after they were stored at room temperature. Therefore, these results suggest that the smoke-substance may possess long half-lives to produce the radicals which inactivate NO, and to inhibit the increase in cyclic GMP levels in nerve terminals. The interference with NO may explain the part of mechanism in effects of cigarette smoke on neuronal functions.

Nerve growth factor induces resistance of PC12 cells to nitric oxide cytotoxicity

Nitric oxide (NO) donors, sodium nitroprusside and NOC 7, caused pheochromocytoma (PC12) cell death in a concentration and time-dependent manner. This cytotoxicity was blocked by the NO trapping agent, oxyhemoglobin. A membrane permeable cGMP analogue had no cytotoxicity in a reasonable concentration. Moreover, the selective inhibitor of cGMP-dependent protein kinase, KT5823, had no effect on NOC 7 cytotoxicity. These results suggest that NO caused PC12 cell death but not through the cGMP pathway. Additionally, this NO-induced PC12 cell death is not accompanied by DNA fragmentation. Nerve growth factor (NGF), which is able to rescue PC12 cells from serum deprivation, failed to protect PC12 cells from NO-induced cell death by acute treatment. However, PC12 cells differentiated by NGF treatment for more than 3 days did not die after NO exposure. The differentiated PC12 cells, but not undifferentiated cells, expressed NO synthase (NOS). NGF-differentiated PC12 cells acquired the resistance to NO, by a mechanism not yet identified, accompanied by the expression of NOS.

Effects of 1-[3-(4-benzhydryl-1-piperazinyl)propyl]-3- (1H-imidazol-1-ylmethyl)-1H-indole-6-carboxylic acid with thromboxane A2 synthetase inhibitory and H1-blocking activities on anaphylactic bronchospasm

1-[3-(4-Benzhydryl-1-piperazinyl)propyl]-3-(1H-imidazol-1-ylmethyl )- 1H-indole-6-carboxylic acid (CAS 172544-75-1, KY-234) was characterized pharmacologically. KY-234 (10(-9)-10(-6) mol/l) and ozagrel (10(-8)-10(-5) mol/l) inhibited the production of thromboxane A2 (TXA2) in rabbit platelets. KY-234 and pyrilamine at concentrations of 10(-9)-10(-6) mol/l relaxed the isolated guinea pig trachea contracted with histamine, while neither drug attenuated the heart rate increased by histamine. Cimetidine antagonized histamine in the right atrium but not in the trachea. KY-234 (10(-8)-10(-5) mol/l) and ozagrel (10(-7)-10(-4) mol/l), but not pyrilamine, attenuated the contraction induced by leukotriene D4 (LTD4) and platelet-activating factor in the lung parenchymal strips. In anesthetized guinea pigs, KY-234 (1-10 mg/kg p.o.) inhibited the LTD4- and histamine-induced bronchoconstriction. Ozagrel and terfenadine inhibited only the LTD4- and histamine-induced constrictions. KY-234 (3-30 mg/kg p.o.) inhibited the anaphylactic bronchoconstriction continuously for 15 min after antigen-challenge. Terfenadine (3-30 mg/kg p.o.) inhibited the constriction more strongly within the first 5 min (fast phase) than it did within 5 to 15 min (slow phase) after the challenge. Ozagrel (100 mg/kg p.o.) slightly attenuated only the constriction during the slow phase. These findings demonstrated that KY-234 has a selective TXA2 synthetase-inhibitory and H1-blocking activity and protects against anaphylactic bronchospasm more effectively than a TXA2 synthetase inhibitor or H1-blocker alone.

Sensitive determination of nitrotyrosine in human plasma by isocratic high-performance liquid chromatography

A highly sensitive and simple isocratic high-performance liquid chromatographic method was developed for determination of 3-nitrotyrosine in human plasma with precolumn derivatization with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole. The precision of the method was satisfactory (coefficient of variation 4.8%), and the detection limit was established at 0.1 pmol of 3-nitrotyrosine allowing the determination at the level of 6 pmol/ml in human plasma. The recoveries of 3-nitrotyrosine and alpha-methyltyrosine, an internal standard, were 89.3 +/- 7.1 and 85.7 +/- 7.6%, respectively. The 3-nitrotyrosine level was 31 +/- 6 pmol/ml (mean +/- S.D., n = 9) in plasma from healthy volunteers. Since 3-nitrotyrosine is a stable product of peroxynitrite, an oxidant formed by a reaction of nitric oxide and superoxide radicals, the measurement of its plasma concentration may be useful as a marker of nitric oxide-dependent oxidative damage.

[A case of bilateral infarction of medial pontomedullary junction]

A 69-year-old man suffered from dizziness and nausea after work, and was admitted to our hospital on the next day. On admission, he showed bilateral horizontal nystagmus and left hemiparesis. On the 3rd day he vomited frequently, and the dizziness became worse. Bilateral horizontal and upward gaze palsy and bilateral facial nerve palsy were observed. Brain MRI on the 5th day disclosed bilateral upper medial medullary infarction that extended to the pontomedullary junction. Cerebral angiography on the 13th day revealed occlusion of the right vertebral artery. This case did not show typical medial medullary syndrome. The mechanism was unknown, but similar cases were reported. Recently, many cases of medullary infarction are reported with the progress of MRI technology. It is suggested that the addition of the new concepts on the conventional syndromes of medullary infarction is necessary.

Frequent loss in chromosome 8p loci in liver cirrhosis accompanying hepatocellular carcinoma

Most hepatocellular carcinoma (HCC) is preceded by liver cirrhosis, but the genetic changes involved in cirrhosis are not well understood. We therefore studied loss of heterozygosity (LOH) in cirrhotic and neoplastic foci in livers of 14 patients with HCC. The samples, microdissected from paraffin-embedded tissues, were analyzed using a polymerase-chain-reaction-based assay for dinucleotide repeat polymorphisms on 8p. Of the 14 cases, 13 showed constitutional heterozygosity for the microsatellite markers. In 7 (54%) of these 13 informative cases, LOH was detected in the primary HCC and, in these 7 doubly informative (informative and LOH-positive in primary HCC) cases, LOH was found in 16 (70%) of 23 liver cirrhotic foci. The pattern of 8p allelic loss was identical in each doubly informative tumor; however, some of the liver cirrhotic foci harbored an 8p loss identical to that seen in the primary HCC, some harbored a different 8p loss, and some did not harbor any 8p loss. The remaining 6 cases without LOH on 8p in HCC showed no 8p loss in any cirrhotic foci. Presumably HCC could develop from cirrhotic cells harboring 8p loss.

A new gastric ulcer model induced by ischemia-reperfusion in the rat: role of leukocytes on ulceration in rat stomach

A new model of gastric ulcer involving damage to the muscularis mucosae was developed by clamping the celiac artery in rat to induce ischemia-reperfusion (I-R) injury. Although erosions with falling off of the gastric mucosa were observed immediately, 24 and 36 hours after the I-R, gastric ulcers involving the injury of muscularis mucosae were observed in the area of gastric glands at 48 and 72 hours after initiation of injury. Administration of omeprazol, a proton pump inhibitor, or pentoxifylline, an anti-leukocyte drug, just after the initiation of injury significantly decreased the total area of ulcers at 72 hours. A combination of omeprazol and pentoxifylline was more effective than either drug alone. An anti-leukocyte adhesion molecule (anti-CD18 antibody) also showed significant inhibitory effect on the development of ulcers at 72 hours and the infiltration of leukocytes into both submucosa and mucosa. These results indicate that in our model, gastric acid together with leukocytes contribute to the development of ulcers following erosions. This model may be used to investigate the mechanisms of the development of gastric ulcer and evaluate antiulcer drugs in a preclinical setting.

Intraventricular administration of estradiol modulates rat prolactin secretion and synthesis

The effect of estradiol (E2) on rat tuberoinfundibular dopaminergic (TIDA) neurons was examined in vivo, employing chronic intraventricular (i.c.v.) infusion technique using an osmotic mini-pump. The activity of TIDA neurons was assessed by the release and synthesis of prolactin (PRL) in the rat pituitary gland and by the changes in the 3, 4-dihydroxyphenylacetic acid (DOPAC) and dopamine (DA) levels and in the DOPAC/DA ratio in the rat hypothalamus. We also examined the [3H] E2 binding in the rat hypothalamus. Ovariectomized female Wistar rats with E2 replacement were treated with daily i.c.v. infusion of 1 microM of E2 or saline vehicle for 1, 3, and 7 days using the Alzet osmotic mini-pump and brain infusion kit. At 1 day of i.c.v. infusion of E2, the serum PRL level was significantly decreased compared with that in the vehicle group. Northern blot analysis of the total RNA isolated from the pituitary glands demonstrated a decrease in the PRL gene transcript level in the E2 group. At 3 days of E2 treatment, however, the serum PRL level was significantly increased compared with that of the vehicle-injected group and Northern blot analysis also demonstrated that the PRL gene transcript level was increased in the E2 group. At 7 days of E2 administration, there were no significant differences between the E2 and vehicle groups in either serum PRL or PRL gene transcript levels. There was a significant increase in the DOPAC/DA ratio after 1 day in the E2 group. However, no significant effects of E2 on this ratio were observed at 3 and 7 days of treatment. The DOPAC concentration in the E2 group was significantly increased at day 1 and significantly decreased at day 3, compared with that of the respective time in vehicle group. At day 7 there was no significant change in DOPAC concentration in either groups. The DA concentrations in the hypothalamus was not changed on any day in either group. Specific [3H] E2 binding was observed in the rat hypothalamus. These data suggest that E2 may have a biphasic effect on the accumulation of PRL gene transcripts and on the PRL secretion in the rat pituitary by first stimulating and then inhibiting the TIDA neuronal activity.

Temporal and spatial distribution of ferredoxin isoproteins in tomato fruit

Five ferredoxin (Fd) isoproteins (FdA, FdB, FdC, FdD, and FdE) were isolated from tomato (Lycopersicon esculentum cv Momotaro) fruit. These isoproteins showed differential temporal and spatial accumulation patterns. FdA and FdC were present in leaves. FdE was present in roots, and FdB and FdD were fruit-specific. During fruit growth, the relative abundance of FdA decreased and that of FdE increased. The FdE/FdA ratio was higher in the inner tissues of the fruit than in the outer tissue, and it was correlated with starch accumulation. In darkgrown fruit the contents of FdA, FdB, and FdC, as well as chlorophyll, decreased remarkably relative to their light-grown counterparts; however, the contents of FdE and starch did not change significantly. Under in vitro conditions FdE showed higher cytochrome c reduction activity than FdA and FdB. These results, together with their N-terminal sequences, indicate that both photosynthetic- and heterotrophic-type Fd isoproteins are present in tomato fruit.

[Recovery from descending necrotizing mediastinitis and multiple organic failure after seven months of mechanical ventilation]

A 61-year-old man with a history of hypertension and diabetes mellitus had a tooth extracted. Nine days later, he was admitted to the hospital with complaints of high fever, dyspnea, and anterior chest pain. Physical examination revealed a drowsy man with a fever of 38.2 degrees C, blood pressure of 66/44 mmHg, and marked redness and swelling from the neck to anterior part of the chest. Laboratory examination indicated severe infection and multiple organ failure, consisting of cardiac, respiratory, renal, and hepatic failure, with disseminated intravascular coagulation. Chest X-ray and CT-scan films showed abscesses extending from the neck to the mediastinum, and bilateral pleural effusion. Immediately, he was treated with catecholamines, furosemide, mechanical ventilation with a high concentration of oxygen, continuous drainage, repeated skin incisions, and broad-spectrum antibiotics. In addition, steroid pulse therapy was administered for persistent respiratory failure. On the 28th hospital day, a fistula developed between the trachea and the mediastinum, and an intratracheal tube had to be inserted through the fistula. On the 212 th hospital day, after intravenous hyperalimentation, continuous intravenous insulin infusion, and administration of broad-spectrum antibiotics, catecholamines, and furosemide, the patient was weaned from mechanical ventilation. A restrictive ventilatory defect due to ankylosis and atrophy of underused muscles was noted after weaning, but the PaO2 was high with a low dose of oxygen (1 to 2 l/min), and 21 months later, the blood gases were normal while the patient was breathing room air. As of January, 1996, he was undergoing rehabilitation to promote his recovery from ankylosis, muscle atrophy, and speech dysfunction.

Altered prostaglandin metabolism induced by angiotensin-converting enzyme inhibitors in broncho-alveolar lavage fluid of the guinea pig

The aim of this study was to investigate if prostaglandin (PG) metabolism is altered by angiotensin-converting enzyme (ACE) inhibitors as determined in the broncho-alveolar lavage fluid (BALF) of the guinea pig. Enalapril or imidapril was orally administered once a day for 2 weeks to Hartley male guinea pigs. Twenty-four hours after the last treatment, BALF was collected and the concentrations of PGI2, thromboxane A2 (TXA2) and PGE2 were measured by enzyme immunoassay. Enalapril significanlty P < 0.05) increased the TXA2 content, which was inhibited by indomethacin treatment and significantly (P < 0.05) decreased the PGI2 content. Imidapril, however, did not affect TXA2 or PGI2 generation. These findings suggest that altered PG metabolism may be associated with coughing as a side effect of enalapril.

A new murine lymphocytotoxic monoclonal antibody recognizing HLA-A2, -A28 and -A9

Monoclonal antibodies recognizing polymorphic as well as monomorphic epitopes on HLA antigens are important tools for understanding the immunobiology of HLA molecules. We immunized BALB/c mice with a HLA-A2 transfectant and screened for hybridomas which reacted with a HLA-A2 transfectant but not with a HLA-B75 transfectant. After subcloning by limiting dilution four times, a hybridoma secreting a monoclonal antibody (mAb) (IgG 2a, kappa) designated 1-145 was established. 1-145 reacted with Epstein-Barr virus transformed B lymphoblastoid cell lines (B cell lines) which expressed HLA-A2, -A28, -A23 and -A24. The titer of 1-145 in culture supernatant against HLA-A2 and -A28 antigens was similar and the titer against HLA-A23 was lower. 1-145 reacted with cells expressing HLA-A24 but the titer against HLA-A24 antigens was even lower than that against HLA-A23 antigens. The HLA-A24 antigens on the peripheral blood lymphocytes were not detected by 1-145 possibly due to the lower expression compared to the B cell lines. These differences of the titers were reflected to microlymphocytotoxicity assay in which 1-145 culture supernatant lysed all PBLs expressing HLA-A2,-A28 and -A23 but did not lyse PBLs expressing HLA-A24. Published deduced amino acid sequence data of HLA class 1 molecules indicate that Lys in position 127 may be critical for 1-145 binding.

EAAT4 is a post-synaptic glutamate transporter at Purkinje cell synapses

To study cellular and subcellular localizations of the glutamate transporter EAAT4, antibody was raised against the N-terminal peptide. On immunoblotting the antibody recognized a band in membrane extracts from the cerebellum, but not from the forebrain. Immunohistochemistry revealed that its distribution was restricted to the cerebellar molecular layer, where the immunoreactivity was observed as numerous punctate stainings. Electron microscopy showed the antibody to label dendritic spines of the Purkinje cells. EAAT4 is, therefore, a Purkinje cell-specific, postsynaptic transporter. Together with dense localization of other transporter subtypes in Bergmann astrocytic membranes, Purkinje cell synapses are thus provided with distinct glutamate transporter subtypes at discrete synaptic elements, which would play important roles in regulating excitability of the Purkinje cells and protecting against excitotoxicity.

[Clinical studies on vancomycin in the treatment of MRSA infection]

We evaluated the effectiveness and safety of vancomycin (VCM) alone and in combination with beta-lactam antibiotics in the treatment of MRSA infections, and obtained the following results: 1. Effectiveness. (1) In cases of MRSA infections alone, the improvement rate was 71.4% (5/7 patients) with VCM alone and 77.8% (35/45) with VCM in combination with beta-lactam antibiotics. (2) In cases of polymicrobial infections, few cases were treated with VCM alone, but the improvement rate in combination use with beta-lactam antibiotics was 71.8% (28/39). 2. Bacteriological effect. (1) In cases of single infection with MRSA, the rate of bacterial eradication was 71.4% (5/7) with VCM alone and 68.2% (30/44) with VCM in combination with beta-lactam antibiotics. (2) In cases of polymicrobial infections, few cases were treated with VCM alone, but the rate of bacterial eradication in combination use with be ta-lactam antibiotics was 63.2% (24/38) against MRSA and 31.6% (12/38) against polymicrobial agents including MRSA. 3. Safety. Occurrences of adverse reactions and abnormal laboratory test values when VCM was used alone or when it is used in combination with another drug were about the same in these uses. As a whole, advance reactions were observed in 16 patients (9.5%). Main adverse reactions were whole body redness, drug eruption, and rash etc. Abnormal laboratory test values were observed mainly in hepatic functions, and renal functions. 4. VCM concentrations in blood was determined in 38 patients. Doses of 0.5 g and 1.0 g of VCM was administered by intravenous drip infusion over a period of 1 to 2 hours, and mean blood concentrations 1 to 2 hours after the completion of drip infusion were 25.4 micrograms/ml and 14.4 micrograms/ml, respectively. 5. Synergic effects between VCM and other antibiotics tested were observed in FIC index against all of the six MRSA strains isolated from six patients, and the clinical effects of improvement or better were obtained against five of them.