Cloning and characterization of mdc genes encoding malonate decarboxylase from Pseudomonas putida

The DNA fragment encoding malonate decarboxylase, involved in malonate assimilation, was cloned from Pseudomonas putida. The 11-kb DNA fragment contained nine open reading frames, which were designated mdcABCDEGHLM in the given order. N-terminal protein sequencing established that the mdcA, mdcC, mdcD, mdcE and mdcH genes encoded subunits alpha, delta, beta, gamma and epsilon of the malonate decarboxylase, respectively. Malonate decarboxylase was functionally expressed in Escherichia coli from plasmid harboring the entire gene cluster or the mdc genes lacking the mdcL and mdcM genes. The mdcL and mdcM genes encode membrane proteins and disruption of the genes of P. putida by the insertion of a kanamycin resistance cassette reduced the malonate uptake activity of the organism. Thus, we conclude that MdcLM is a malonate transporter.

Malonate decarboxylase of Pseudomonas putida is composed of five subunits

Two different forms of malonate decarboxylase were purified from Pseudomonas putida. The active form was composed of the five different subunits alpha (60 kDa), beta (33 kDa), gamma (28 kDa), delta (13 kDa), and epsilon (30 kDa) and the inactive form was composed of the four subunits lacking the epsilon subunit. The former catalyzed the decarboxylation of malonate to acetate, but the latter could not, although it retained both activities of acetyl-CoA:malonate CoA transferase and malonyl-CoA decarboxylase. The delta subunit of the active form was acylated by the incubation with [2-14C]malonyl-CoA, but the delta subunit of the inactive form was not labeled. From the above results and the N-terminal amino acid sequence analysis, it was concluded that the epsilon subunit was an essential subunit to function as malonyl-CoA:ACP transacylase, which was an indispensable component of the enzyme for the cyclic decarboxylation of malonate.

Antitumor effect of medium-chain triglyceride and its influence on the self-defense system of the body

Medium-chain triglyceride (MCT), long-chain triglyceride (LCT), and their mixture were compared in reference to both cytotoxic effect against human tumor cells and influence on the immune system. MCT showed more potent cytotoxicity than LCT. Continuous contact with MCT also inhibited the cytotoxic effect of lymphokine-activated killer (LAK) cells much more strongly than LCT. However, there is a discrepancy between the concentration of MCT, or the mixture, that could suppress the growth of tumor cells and the concentration that inhibited the cytotoxicity of LAK cells. Moreover, no damage was observed in PBL or LAK cells or in their cytotoxicity when the cells were incubated with TG for 2 h a day. Thus, short-term contact with TG could inhibit tumor growth while immune system was maintained within normal range. Clinically fine control of the concentration of injected triglycerides, especially MCT, can be expected to provide potent antitumor effect and maintenance of normal immune system.

Changes in size of intracellular pools of coenzyme A and its thioesters in Escherichia coli K-12 cells to various carbon sources and stresses

Intracellular pools of three CoA molecular species of coenzyme A, CoASH, acetyl-CoA, and malonyl-CoA, in Escherichia coli K-12 cells were studied by acyl-CoA cycling method in replacement culture. The sizes and compositions of CoA pools starved for a carbon source changed within minutes after the addition of one of various carbon sources. A large acetyl-CoA pool formed after the addition of D-glucose, D-fructose, D-mannose, glycerol, or sorbitol, but there was little change when L-glucose, sucrose, maltose, succinate, or acetate was added. The beta-anomer of D-glucose was assimilated 10 times faster than the alpha-anomer. Intracellular CoA pools also changed with stress: in the pH, incubation temperature, or with osmotic stress. The sizes and compositions of CoA pools were not affected by pH changing between 4 and 8, but the breakdown of acetyl-CoA and CoASH was greater at pH 9 than at pH 4 to 8. Production of acetyl-CoA was greatest at 40 degrees C, and at 50 degrees C, an acetyl-CoA pool did not form at all and the size of the CoASH pool declined. When the organism was stressed by the addition of NaCl at concentrations of more than 0.6 M, little acetyl-CoA was produced. The total CoA pool (the sum of the concentrations of CoASH, acetyl-CoA, and malonyl-CoA) remained within the limits of 0.83-1.40 nmol/mg of dry cell weight (0.30-0.52 mM). Whenever acetyl-CoA increased, CoASH decreased. Therefore, the acetyl-CoA/CoASH ratio is an important index of facultative anaerobes that reflects the state of carbon and energy metabolism in vivo.

Random amplified polymorphic DNA (RAPD) analyses for discriminating genotypes of Microcystis cyanobacteria

Random amplified polymorphic DNA (RAPD) analysis was used to discriminate genotypes in five species of Microcystis cyanobacteria. Strains of each group with the identical allozyme genotype (T. Kato et al., Algol. Stud., 1991, 129-140; M. Watanabe, in "Toxic Microcystis," ed. by M.F. Watanabe et al., CRC Press, Tokyo, 1966, pp. 13-34) gave similar RAPD patterns characterizing the respective group. On the other hand, no similarities in RAPD patterns were observed among strains of which allozyme genotypes were different. A good accordance between the RAPD analysis and allozyme divergence indicated a high reliability of both methods for discrimination of the affiliated groups of Microcystis. Several amplified DNA fragments, which were expected to be markers for a particular taxon with identical allozyme genotype, were also observed on the RAPD patterns. Genetic homogeneities of M. novacekii, M. viridis, and M. wesenbergii were shown by RAPD analysis as well as the allozyme genotype. However, significant variations were observed in M. aeruginosa and M. ichthyoblabe in the levels of DNA and proteins (allozymes).

Thoracic dumbbell-shaped neurinoma treated by unilateral hemilaminectomy with partial costotransversectomy--case report

A 56-year-old male was admitted in January 1994, with back pain persisting for 2 months. Magnetic resonance imaging disclosed a homogeneously enhanced mass occupying the spinal canal at the T-8 level and extending into the retropleural space through the left intervertebral foramen between T-8 and T-9. The diagnosis was a thoracic dumbbell-shaped neurinoma. The tumor was successfully removed through a posterolateral approach using hemilaminectomy and partial costotransversectomy with preservation of ipsilateral joint facets. Histological examination indicated neurinoma. This approach allows excellent visualization of anterior paraspinal components of the tumor, preserves important anatomic structures, and requires minimal compression of the cord for removal of the lesion.

Characterization of an extremely thermophilic and oxygen-stable membrane-bound hydrogenase from a marine hydrogen-oxidizing bacterium Hydrogenovibrio marinus

The membrane-bound hydrogenase from a marine hydrogen-oxidizing bacterium Hydrogenovibrio marinus was characterized as highly oxygen-tolerant, extremely thermophilic and thermostable in its membrane-bound form. The optimum temperatures for H2 oxidation and H2 evolution were 90 and 80 degrees C, respectively. The enzyme retained 90% of its activity after heating at 70 degrees C for 50 min under air and retained full activity at 90 degrees C for 80 min under hydrogen. The optimum pH values were 5.5 (H2 evolution) and 9.4 (H2 oxidation), and the activity ratio (H2 evolution/H2 oxidation) was high (50.3) at pH 5.5. The hydrogen evolution from reduced methyl viologen continued at high temperatures and acidic pH with the continuous addition of sodium dithionite.

Changes in the size and composition of intracellular pools of nonesterified coenzyme A and coenzyme A thioesters in aerobic and facultatively anaerobic bacteria

Intracellular levels of three coenzyme A (CoA) molecular species, i.e., nonesterified CoA (CoASH), acetyl-CoA, and malonyl-CoA, in a variety of aerobic and facultatively anaerobic bacteria were analyzed by the acyl-CoA cycling method developed by us. It was demonstrated that there was an intrinsic difference between aerobes and facultative anaerobes in the changes in the size and composition of CoA pools. The CoA pools in the aerobic bacteria hardly changed and were significantly smaller than those of the facultatively anaerobic bacteria. On the other hand, in the facultatively anaerobic bacteria, the size and composition of the CoA pool drastically changed within minutes in response to the carbon and energy source provided. Acetyl-CoA was the major component of the CoA pool in the facultative anaerobes grown on sufficient glucose, although CoASH was dominant in the aerobes. Therefore, the acetyl-CoA/CoASH ratios in facultatively anaerobic bacteria were 10 times higher than those in aerobic bacteria. In Escherichia coli K-12 cells, the addition of reagents to inhibit the respiratory system led to a rapid decrease in the amount of acetyl-CoA with a concomitant increase in the amount of CoASH, whereas the addition of cerulenin, a specific inhibitor of fatty acid synthase, triggered the intracellular accumulation of malonyl-CoA. The acylation and deacylation of the three CoA molecular species coordinated with the energy-yielding systems and the restriction of the fatty acid-synthesizing system of cells. These data suggest that neither the accumulation of acetyl-CoA nor that of malonyl-CoA exerts negative feedback on pyruvate dehydrogenase and acetyl-CoA carboxylase, respectively.

Increased histidine preference during specific alteration of rhythm of environmental temperature stress in rats

It has been reported that specific alteration of rhythm of environmental temperature (SART) stress induces various physiological changes. In this study, changes in taste preference during SART stress were investigated in rats. Rats were given free access to six amino acid solutions, saline, and water in a choice paradigm. During SART stress, daily food intake increased significantly by 50% whereas the rate of body weight gain decreased significantly to one third that observed during the prestress baseline period. In addition, consumption of histidine solution increased significantly, whereas intakes of water, monosodium glutamate, saline, glycine, arginine, lysine, and threonine were unaffected. Results suggest that a specific preference for histidine emerges during SART stress, which may be related to the stress-induced changes in the histamine turnover in the brain and peripheral tissues.

Increased histidine preference during specific alteration of rhythm of environmental temperature stress in rats

It has been reported that specific alteration of rhythm of environmental temperature (SART) stress induces various physiological changes. In this study, changes in taste preference during SART stress were investigated in rats. Rats were given free access to six amino acid solutions, saline, and water in a choice paradigm. During SART stress, daily food intake increased significantly by 50% whereas the rate of body weight gain decreased significantly to one third that observed during the prestress baseline period. In addition, consumption of histidine solution increased significantly, whereas intakes of water, monosodium glutamate, saline, glycine, arginine, lysine, and threonine were unaffected. Results suggest that a specific preference for histidine emerges during SART stress, which may be related to the stress-induced changes in the histamine turnover in the brain and peripheral tissues.

Emotional and behavioral correlates of mediodorsal thalamic neurons during associative learning in rats

Neuronal activity was recorded from the mediodorsal thalamic nucleus (MD) of behaving rats that were trained to lick a protruding spout just after a conditioned stimulus to obtain reward or to avoid shock. Conditioned stimuli included both elemental (auditory or visual stimuli) and configural (simultaneous presentation of auditory and visual stimuli predicting reward outcome opposite that predicted by each stimulus presented alone) stimuli. Of 122 MD neurons responding during the task, the activity of 13 increased just before licking only during the task, but not before spontaneous licking during the intertrial interval (conditioned behavior related). These conditioned behavior-related neurons were located mainly in the lateral MD, which has intimate anatomical connections with motor-related areas such as anterior cingulate and striatum. The activity of the other 109 neurons was related to conditioned stimulation (conditioned stimulus related). Most of these neurons responded differentially to both elemental and configural stimuli in terms of reward contingency, and also changed their responses during extinction and relearning trials. Conditioned stimulus-related neurons with latencies < 300 msec were located mainly in the rostromedial MD, which receives afferents from the basolateral nucleus of the amygdala in which sensory information from various sources converge. Furthermore, most differential neurons that were tested responded during the delay period in a reward task in which a delay was imposed between the conditioned stimulus and reward delivery. The present results, along with previous anatomical studies, suggest the existence of two limbic circuits: anterior cingulate-striatum-lateral MD (motor) and amygdala-medial MD-orbital prefrontal cortex (short-term memory/emotion).

[Transverse myelitis in a patient with primary antiphospholipid syndrome--a case report]

A case of acute transverse myelitis following primary antiphospholipid syndrome was presented. The patient was 32-year-old Japanese female who was admitted to our hospital with paresthesia and weakness of the right upper extremity in September 1995. Neurological examinations revealed slight weakness and hypesthesia of the right arm and leg, impairment of vibration sense below the right knee, and hyperreflexia on the right side. There was no apparent history of systemic lupus erythematosus or multiple sclerosis. Laboratory investigations disclosed raised anticardiolipine antibody level of the IgG class. A magnetic resonance (MR) imaging of the cervical spine revealed changes in the spinal cord at C3-5. A gradual enlargement of the cord at C3-5 level was revealed on T1-weighted sagittal images; increased signal intensity at these same levels was visualized on T2-weighted images. Following administration of contrast material, an area of increased signal intensity was visualized within the cord extending from the C3/4 level to the C4/5 level in sagittal views and was located in the right lateral and posterior funiculus of the cord in axial views. After the admission, the patient's neurological symptoms worsened, and then we treated her by steroid pulse therapy. After that, the patient's symptoms gradually disappeared and the abnormal signal intensity of the spinal cord on an MR imaging disappeared. No evidence of recurrence was yielded by neurological examinations or neuroimaging studies. Antiphospholipid antibodies should be studied in all patients with transverse myelitis whether known to systemic lupus erythematosus, multiple sclerosis or not.

Cerebral venous sinus thrombosis associated with systemic multiple hemangiomas manifesting as chronic subdural hematoma--case report

A 35-year-old male was admitted with headache, nausea, and vomiting persisting for 2 days. Computed tomography (CT) revealed a left chronic subdural hematoma. Cerebral angiography demonstrated cerebral venous sinus thrombosis (CVST). He had presented with a subcutaneous mass involving the neck at age 2 years, which was shown to be a cavernous angioma, and thereafter shown signs of consumptive coagulopathy with systemic multiple hemangiomas. Burr hole aspiration of the hematoma was performed. Seventy-two-hours later, he developed clouding of consciousness and right hemiparesis. CT revealed a fresh hematoma in the operated subdural cavity and hemorrhagic diathesis manifested. A frontotemporoparietal large craniotomy was performed to remove the hematoma. Extensive electrocauterization was required. He had a satisfactory postoperative course. Collateral venous pathways, resulting from the CVST due to systemic multiple hemangiomas, may have caused hemodynamic stress in the bridging veins which subsequently induced chronic subdural hematoma.

[Magnetic resonance imaging of supratentorial and parafalcial empyema]

The authors report the MR imaging of two patients with multiple subdural empyemas, including one in the interhemispheric fissure. MRI demonstrated convexity and interhemispheric collections which were mild hyperintense relative to CSF, hypointense relative to gray and white matter on T1W1, and marked hyperintense relative to CSF, and brain on T2W1. On the basis of signal intensity differences, MRI can distinguish subdural empyemas from most sterile effusions and chronic subdural hematomas with similar CT appearances. MRI was found to be clearly more sensitive to subdural empyemas than CT, though such lesions missed on CT were considered to be relevant. MR was superior to CT in demonstrating the nature, presence, and extent of these lesions. In both cases, the capsule of the lesions demonstrated enhancement, and connection between each lesion was obvious on contrast-enhanced MRI. It seems that contrast-enhanced MR image may detect encapsulation of an abscess which can not be detected from contrast-enhanced CT. We emphasized that the most significant factor in the successful surgical management of multiple subdural empyema, particularly including interhemispheric collections is the accurate location of pus. This can be reliably achieved with MR imaging.

An isolated dissecting aneurysm of the superior mesenteric artery: report of a case

We report herein the case of a 56-year-old man found to have an isolated dissecting aneurysm of the superior mesenteric artery (SMA) after he presented with a 3-day history of postprandial epigastralgia of sudden onset. An echogram showed marked dilatation of the SMA and a high level of peripheral echoes in a linear fashion within its lumen. A thin-section contrast enhanced computed tomography revealed a thin flap, separating two distinct well-enhanced lumina. Angiography confirmed the presence of a localized dissecting aneurysm of the SMA. The patient was treated conservatively and has since been followed up as an outpatient. Following the presentation of this case, the problems regarding the diagnosis and management of this rare disease are discussed based on a review of the literature.

Positive chronotropic and inotropic effects of higenamine and its enhancing action on the aconitine-induced tachyarrhythmia in isolated murine atria

Aconitine and higenamine are the components of aconite root. We investigated the cardiac effects of these compounds on murine right and left atria and the interaction of higenamine with aconitine on the rate of spontaneously beating right atria. Higenamine increased the rate (EC50 = 38 nM) and the force of contraction (EC50 = 97 nM), the maximal responses being comparable with those of isoproterenol. The positive chronotropic effect of higenamine was antagonized by propranolol (30-300 nM) and practolol (10 nM-3 microM), but not by butoxamine (1 microM), indicating that it was a beta 1-adrenoceptor-mediated action. The positive chronotropic effect of higenamine was not changed by pretreatment with reserpine (4 mg/kg, i.p., 4 hr). Aconitine (0.16-0.25 microM) induced tachyarrhythmia in right atria was attenuated by quinidine (1 microM), atropine (8.6 microM) and AF-DX 116 (8.6 microM), suggesting that aconitine activates sodium channels and muscarinic receptors. Higenamine (2.5 nM) and dobutamine (1 nM) did not cause chronotropic effects by themselves, but enhanced the aconitine-induced tachyarrhythmia. These results indicate that higenamine is a beta 1-adrenoceptor full agonist in murine atria and that the aconitine-induced tachyarrhythmia is augmented by the beta 1-adrenergic action of higenamine.

Structural components of beta-eudesmol essential for its potentiating effect on succinylcholine-induced neuromuscular blockade in mice

beta-Eudesmol, a sesquiterpenoid alcohol isolated from Atractylodes lancea rhizoma, potentiates the neuromuscular blocking effect of succinylcholine (SuCh). The potentiating effect is greater in diabetic muscles than in normal ones. To identify the structural components of beta-eudesmol contributing to this action, we examined the potentiating effect of newly synthesized tertiary alcohols related to beta-eudesmol in phrenic nerve-diaphragm muscle preparations of normal and alloxan-diabetic mice. Potentiating effects were exhibited by cyclohexylidene derivatives but not by cyclohexanone or cyclohexanol derivatives. The compound 2-(3-hydroxy-3-methylbutyl)cyclohexylidene exhibited a potentiating effect, but 3-(3-hydroxy-3-methylbutyl)cyclohexylidene did not. These results indicate that both the presence of an exo-methylene attached to a cyclohexane ring and the distance between the exo-methylene and the hydroxy group in beta-eudesmol are involved in the potentiating effect on SuCh-induced neuromuscular blockade.

Effects of intraventricular administration of neuropeptide Y on feeding behavior in fasted female rats with ventromedial hypothalamic lesions

The role of ventromedial hypothalamic nucleus (VMN) in feeding behavior induced by central administration of porcine neuropeptide Y (NPY) in fasted female rats was investigated focusing on the effect of the intracerebroventricular (i.c.v.) injection of NPY on food intake in rats with VMN lesions after 24 h of food deprivation. Cumulative food intake was measured 1, 3 and 6 h after injection. In Exp. 1, the i.c.v. injection of NPY into intact rats stimulated food intake compared with the injection of saline 1 and 3 h after the injections in a dose dependent manner (1 h; NPY 1 microgram, 3.29 +/- 0.43, 2 micrograms, 4.64 +/- 0.88, 5 micrograms, 5.15 +/- 0.61 vs. saline 2.48 +/- 0.42 g, P < 0.05 in 2 and 5 micrograms). 5 micrograms of NPY significantly stimulated food intake 6 h later. In Exp. 2, i.c.v. injection of NPY (2 micrograms) in VMN-lesioned rats showed no significant effect on food intake compared with the injection of saline 3 weeks after VMN lesioning (1 h; NPY 2 micrograms, 2.46 +/- 0.58 vs. saline 2.39 +/- 0.12 g). These results suggest that central administration of NPY enhances food intake in fasted female rats and that the VMN is one of the crucial sites of NPY induced feeding.

Transformation of Pseudomonas putida by electroporation

The optimum electrotransformation conditions were determined for Pseudomonas putida PpY101 with plasmid pSUP104 (9.5 kb) and pSR134 (18.6 kb). Field strength was a very important parameter for electrotransformation efficiency. Optimum efficiencies (1.1 x 10(5) transformants/micrograms DNA) with pSUP104 and pSR134 were obtained at a field strength of 12.5 kV/cm, a time constant of about 4.5 ms (resistance setting of 200 ohms), a supercoiled DNA concentration of 100 ng/ml, and a cell concentration of 10(9)/ml. Because the efficiency obtained is high enough, electrotransformation is useful for the direct cloning of P. putida PpY101. No significant relationship between plasmid size and electrotransformation efficiency was observed. These efficiencies were about 4.5 times higher than those using the MgCl2 method. Under these conditions, electrotransformation efficiencies of relaxed plasmid DNA treated with topoisomerase I and that linearized by EcoRI digestion were high.

[Cerebellar infarcts that require differentiation from tumors: diagnosis with MRI]

It is often difficult to differentiate cerebellar infarct with cerebellar swelling from neoplastic disorders, because former can be shown as cerebellar mass with marked contrast enhancement on CT scan. We analyzed radiologically three cases with cerebellar infarction by using MRI, conventional CT scan and angiography. Two cases in the acute stage could be diagnosed as cerebellar infarction by MRI alone based on the following findings: 1) the lesion was distributed in the territory of cerebellar arteries; 2) the normal pattern of cerebellar folia and fissures was preserved in Gd enhancement MRI image; 3) characteristics of MRI intensity were compatible with hemorrhagic infarction. The other case in the chronic stage showed peculiar enhancement, which was unusual for infarction. It was diagnosed as cellular infarction with reference to the angiographic findings. MRI is generally useful to obtain early diagnosis of tumor-like cerebellar infarcts, and proper treatment should be started as early as possible.

[Clinical analysis of the fatal cases of adult malignant gliomas after aggressive treatment]

Six patients operated on for supratentorial malignant astrocytomas and seven patients operated on for glioblastoma multiforme were analyzed to evaluate the effect of aggressive surgical resection on the length of survival and causes of death. Early postoperative contrast enhanced CT scan was used to assess the extent of surgical resection. A gross total resection was considered to have been accomplished when there was no evidence of any residual enhanced mass. When 10% or less of the preoperative enhanced mass remained, the resection was classified as a subtotal resection. Subsequent follow-up CT scan showed that a gross total resection was accomplished in nine patients, and a subtotal resection was attained in four patients. The patients' ages ranged from 40 to 78 years (mean, 59 years). The median survival after the first aggressive surgical resection was 18.0 months in patients with malignant astrocytoma and 13.6 months in those with glioblastoma multiforme. The median duration between first operation and recurrence of tumor was 8.8 months in patients with malignant astrocytoma and 11.5 months in those with glioblastoma multiforme. A second aggressive surgical resection for recurrent malignant astrocytoma or glioblastoma multiforme was carried out in four patients (40%) of the evaluated ten patients. The median survival of these patients after reoperation was 8.25 months. Accordingly, aggressive surgical resection of malignant astrocytoma and glioblastoma multiforme is correlated with longer survival and is advocated in the treatment of recurrent tumors. Leptomeningeal dissemination was diagnosed in nine patients (90%) of evaluated ten patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Percutaneous transluminal angioplasty for progressing stroke caused by severe basilar artery stenosis: case report]

We encountered one case of progressing stroke caused by severe basilar artery stenosis. The patient was treated with emergent percutaneous transluminal angioplasty (PTA) with satisfactory results. A 54 year-old woman was admitted 15 minutes after the sudden onset of rt. hemiparesis, rt. hemidysesthesia, dysarthria and consciousness disturbance. CT scan on admission showed no abnormal findings. The consciousness level of the patient deteriorated rapidly from JCS 1 to JCS 20 within 30 minutes from the ictus. An emergent angiogram revealed severe basilar artery stenosis at its middle portion and poorly developed collateral circulation. One hour after the stroke occurred, PTA was performed. Using a 3mm diameter balloon catheter, we introduced the balloon into the stenotic lesion and inflated it 6 times from 4 atm to 8 atm pressure. The patient recovered immediately on the operating table improving from JCS 20 to JCS 1. Rt. hemiparesis also improved. Follow-up MRI showed a small area of ischemic change in the brain stem, but no large infarction appeared. The patient was discharged with no neurosurgical deficits after 30 days of PTA. PTA for basilar artery stenosis is still a controversial subject. One reason is the risk of basilar artery perforating branches occlusion by balloon catheter and the other is the difficulty of introducing a flexible balloon catheter into the basilar artery beyond the acute angulation of the vertebral artery. If those two problems were solved, PTA would be the first-choice therapy for basilar artery stenosis in both acute and chronic stages.

Gastric damage and body weight loss in LHA-lesioned rats: effects of cytoprotective geranylgeranylacetone

We investigated the development of gastric damage and body weight (BW) loss in lateral hypothalamic area (LHA)-lesioned rats, measured 2 h and 1 and 3 days after the lesioning (experiment 1), as well as the effects of geranylgeranylacetone (GGA), a cytoprotective antiulcer agent, on these disorders (experiment 2). In experiment 1, BW of LHA-lesioned rats decreased throughout the 3-day experiment. In LHA-lesioned rats, gastric mucosal lesions appeared 1 day after lesioning in the glandular portion and persisted, whereas those in the rumenal portion appeared only after 3 days. Gastric transepithelial potential differences (PDs) of glandular portion began to decrease after 2 h and had decreased in both portions. Gastric acid output was increased transiently at 2 h but it was not high after 1 day and after 3 days was lower than that in sham-LHA-lesioned rats. In experiment 2, PDs of the rumenal decreased more in LHA-lesioned rats than in sham-LHA-lesioned rats pair fed to LHA-lesioned rats after 3 days. Three days of treatment with GGA (200 mg/kg ip) improved PDs of rumenal and glandular portions in LHA-lesioned rats and reduced lesions of the rumenal portion. Loss of BW in LHA-lesioned rats was significantly but not completely inhibited by GGA. These results indicate that disturbance to the gastric defensive mechanism plays an important role in the development of gastric lesions after LHA lesions and that the impairment of gastric functions may be a partial cause of the loss of BW in LHA-lesioned rats.