Carrier-mediated processes in blood--brain barrier penetration and neural uptake of paraquat

Due to the structural similarity to N-methyl-4-phenyl pyridinium (MPP(+)), paraquat might induce dopaminergic toxicity in the brain. However, its blood--brain barrier (BBB) penetration has not been well documented. We studied the manner of BBB penetration and neural cell uptake of paraquat using a brain microdialysis technique with HPLC/UV detection in rats. After subcutaneous administration, paraquat appeared dose-dependently in the dialysate. In contrast, MPP(+) could not penetrate the BBB in either control or paraquat pre-treated rats. These data indicated that the penetration of paraquat into the brain would be mediated by a specific carrier process, not resulting from the destruction of BBB function by paraquat itself or a paraquat radical. To examine whether paraquat was carried across the BBB by a certain amino acid transporter, L-valine or L-lysine was pre-administered as a co-substrate. The pre-treatment of L-valine, which is a high affinity substrate for the neutral amino acid transporter, markedly reduced the BBB penetration of paraquat. When paraquat was administered to the striatum through a microdialysis probe, a significant amount of paraquat was detected in the striatal cells after a sequential 180-min washout with Ringer's solution. This uptake was significantly inhibited by a low Na(+) condition, but not by treatment with putrescine, a potent uptake inhibitor of paraquat into lung tissue. These findings indicated that paraquat is possibly taken up into the brain by the neutral amino acid transport system, then transported into striatal, possibly neuronal, cells in a Na(+)-dependent manner.

The precore/core promoter mutant (T1762A1764) of hepatitis B virus: clinical significance and an easy method for detection

Recently, a new hepatitis B virus (HBV) mutant with HBe antigen-negative phenotype has been characterized, in which one TATA box-like motif of the precore/core promoter had degenerated: most frequently by both A-->T and G-->A mutations at positions 1762 and 1764, respectively. The clinical significance of this mutant is as yet unknown. In our present study, the T1762 A1764 mutant was sought in sera from HBV-infected blood donors and chronic liver disease patients by directly sequencing a PCR-amplified region of HBVDNA. Also, because the A1764 mutation generates a Sau3AI cleavage site (GGTC-->GATC), we digested the PCR products with Sau3AI to see if cleavage would occur at this specific site. Our results mostly corroborated the earlier report but we found a higher-than-predicted frequency of HBe antigen-positive blood donors positive for the mutant (22%). The titres of HBe antigen in these mutant-positive sera were slightly decreased compared to the titres in wild-type HBV infection. In addition, these blood donors had relatively high (though within the normal range) serum alanine aminotransferase (ALT) levels, suggesting that the T1762 A1764 mutation could be used as a sensitive laboratory marker for insidious hepatitis in these otherwise 'asymptomatic' carriers. The Sau3AI assay, which is much more convenient than sequencing, was shown to be useful for the detection of the T1762 A1764 mutant in an extensive number of clinical samples.

Limitin: An interferon-like cytokine that preferentially influences B-lymphocyte precursors

We have identified an interferon-like cytokine, limitin, on the basis of its ability to arrest the growth of or kill lympho-hematopoietic cells. Limitin strongly inhibited B lymphopoiesis in vitro and in vivo but had little influence on either myelopoiesis or erythropoiesis. Because limitin uses the interferon alpha/beta receptors and induces interferon regulatory factor-1, it may represent a previously unknown type I interferon prototype. However, preferential B-lineage growth inhibition and activation of Janus kinase 2 in a myelomonocytic leukemia line have not been described for previously known interferons.

Biochemical functions of adult rat hepatocytes in primary culture

Liver parenchymal cells from adult rats were isolated by treatment with collagenase and cultured as monolayers in Williams medium E with 10% fetal or calf serum. The additions of dexamethasone and insulin to the medium were essential for maintaining liver functions of the cells. These cells synthesized and secreted various serum proteins into the medium. Gluconeogenesis and glycogenolysis were enhanced by glucagon, and lipogenesis was stimulated by insulin. Many enzymes were also induced by various hormones. These activities were very low in freshly isolated cells, but were restored when the cells were cultured for a few days. Markers of plasma membranes, such as 5'-nucleotidase and insulin receptors, were reduced to half the normal levels on freshly isolated cells, but they were restored to the normal levels during culture of the cells without added hormones. Analysis of the profile of amino acids in the medium showed that freshly isolated cells were in a catabolic state of protein turnover and released branched chain amino acids into the medium, but that cultured cells consumed amino acids, not only for protein synthesis, but also for other metabolic processes, such as gluconeogenesis. These findings show that freshly isolated cells have impaired functions and are unsuitable for use in studies of liver metabolism, but that after culture for a few days the cells regain the activity of normal liver and hance become useful for studies of liver functions. Studies with these cells are simpler and give clear results than studies in vivo.

Calcium-specific precipitation of dentin phosphoprotein: a new method of purification and the significance for the mechanism of calcification

Calcium, but not magnesium or strontium ions, specifically induce the precipitation of dentin phosphoprotein, which is reversibly solubilized by EDTA. This finding is very useful in pruifying dentin phosphoprotein of either a free or matrix-bound type. Bovine dentin phosphoproteins, thus isolated, contain a minimal amount of contaminant protein, unlike previous preparations.

Molecular Genetic Dissection and Neonatal/Infantile Intrahepatic Cholestasis Using Targeted Next-Generation Sequencing

OBJECTIVES

To ascertain a molecular genetic diagnosis for subjects with neonatal/infantile intrahepatic cholestasis (NIIC) by the use of next-generation sequencing (NGS) and to perform a genotype-phenotype correlation.

STUDY DESIGN

We recruited Japanese subjects with NIIC who had no definitive molecular genetic diagnosis. We developed a diagnostic custom panel of 18 genes, and the amplicon library was sequenced via NGS. We then compared clinical data between the molecular genetically confirmed subjects with NIIC.

RESULTS

We analyzed 109 patients with NIIC ("genetic cholestasis," 31 subjects; "unknown with complications" such as prematurity, 46 subjects; "unknown without complications," 32 subjects), and a molecular genetic diagnosis was made for 28 subjects (26%). The rate of positive molecular genetic diagnosis in each category was 22 of 31 (71%) for the "genetic cholestasis" group, 2 of 46 (4.3%) for the "unknown with complications" group, and 4 of 32 (12.5%) for the "unknown without complications" group. The grouping of the molecular diagnoses in the group with genetic cholestasis was as follows: 12 with Alagille syndrome, 5 with neonatal Dubin-Johnson syndrome, 5 with neonatal intrahepatic cholestasis caused by citrin deficiency, and 6 with progressive familial intrahepatic cholestasis or benign recurrent intrahepatic cholestasis with low gamma-glutamyl transpeptidase levels. Several clinical datasets, including age of onset, direct bilirubin, and aminotransferases, were significantly different between the disorders confirmed using molecular genetic diagnosis.

CONCLUSION

Targeted NGS can be used for molecular genetic diagnosis in subjects with NIIC. Clinical diagnosis should be accordingly redefined in the view of molecular genetic findings.

Performance of commercial cultures in fluid milk applications

Six Lactobacillus acidophilus, 5 Bifidobacterium, and 6 Streptococcus thermophilus strains were studied for characteristics that are important to activity and stability in unfermented fluid milk products. Speciation, strain relatedness, frozen concentrate stability, bile sensitivity, and lactase activity were evaluated. The microbiological stability of a culture-containing fluid milk product was also determined. Two of the bifidobacteria cultures contained > 1 strain. Some strains were shown to be closely related or identical by pulsed-field gel electrophoresis of fragmented chromosomal DNA. Selective media that distinguished among all 3 added genera were identified. All lactobacilli and most of the bifidobacteria were resistant to bile concentrations varying from 1 to 3%, and all streptococci were sensitive to bile. Lactase activities were highest for S. thermophilus strains, supporting use of this species in fluid milk and dairy products to aid in the digestion of lactose by consumers. The experimental product evaluated in this study contained 10(7) cfu/ml of both L. Acidophilus and Bifidobacterium spp. and 5 x 10(7) cfu/ml of S. thermophilus. Lactic, but not psychrotrophic, populations were fairly stable during storage. The results suggest that milk formulated with high concentrations of three different genera of probiotic bacteria can be manufactured with commercial strains.

Regulation of STAT3-mediated signaling by LMW-DSP2

Signal transducer and activator of transcription 3 (STAT3), which mediates biological actions in many physiological processes, is activated by cytokines and growth factors, and has been reported to be constitutively activated in numerous cancer cells. In this study, we examined whether low molecular weight-dual specificity phosphatase two (LMW-DSP2) is involved in the regulation of the interleukin 6 (IL-6)/leukemia inhibitory factor (LIF)/STAT3-mediated signaling pathway. IL-6/LIF-induced LMW-DSP2 expression in murine testicular or hepatoma cell lines, while LMW-DSP2 overexpression in 293T cells suppressed IL-6-induced phosphorylation and activation of STAT3. Furthermore, LMW-DSP2 suppressed the expression of IL-6-induced endogenous genes. In contrast, small-interfering RNA-mediated reduction of LMW-DSP2 expression enhanced IL-6-induced STAT3-dependent transcription. In fact, LMW-DSP2 interacted with STAT3 in vivo and endogenous LMW-DSP2 bound to STAT3 in murine testicular GC-1 cells. These results strongly suggest that LMW-DSP2 acts as a negative regulator of the IL-6/LIF/STAT3-mediated signaling pathway.

Electrotransformation of lactobacillus acidophilus group A1

Two strains of Lactobacillus acidophilus Group A1, the neotype ATCC 4356 and a human isolate NCFM-N2, widely used as a dietary adjunct in milk and cultured dairy products, were transformed with plasmid DNA by electroporation. The transformation characteristics exhibited by the two L acidophilus strains were found to differ markedly even though they appeared similar at the genomic level based on the DNA patterns of SmaI restriction fragments. To our knowledge, this is the first report of a consistent, reproducible transformation system of Lactobacillus acidophilus strains comprising the A1 DNA homology group.

Cricoid pressure impedes positioning and ventilation through the laryngeal mask airway

PURPOSE

To assess the effect of cricoid pressure on the positioning of and ventilation through the laryngeal mask airway (LMA).

METHODS

In a double-blind, randomized design, the LMA was inserted with (CP[+] group, n = 20) or without double-handed cricoid pressure (CP[-] group, n = 20). Ventilation through the LMA was assessed by measuring expiratory tidal volume and judged as adequate when a mean expiratory tidal volume of > or = 10 ml.kg-1 could be obtained. The LMA position was examined by fibreoscopy. The position of the mask relative to the cricoid cartilage and the cervical spine was radiologically examined (n = 10 in each group).

RESULTS

Ventilation was adequate in all patients in the CP[-] group but in only five patients (25%) of the CP[+] group (P < 0.001). The glottis was visible fibreoptically below the mask aperture in all patients in the CP[-] group, but in only three patients in the CP[+] group (P < 0.001). Fibreoscopy showed that the mask was not inserted far enough in the remaining 17 patients of the CP[+] group. The reason for unsuccessful ventilation in the CP[+] group was excessive gas leakage (n = 2) and/or partial or complete airway obstruction (n = 13), which was noted fibreoptically. The radiographs showed that the tip of the mask in the CP[-] group was located below the level of the cricoid cartilage (C6 or C7 vertebra). The mask tip in the CP[+] group was above this level (C4 or C5 vertebra) (P < 0.01).

CONCLUSION

Cricoid pressure impedes positioning of and ventilation through the LMA.

Effects of benzene inhalation on lymphocyte subpopulations and immune response in mice

To clarify the immunotoxicity of benzene, the effects of benzene inhalation on T and B lymphocytes and immune responses in mice were examined. BALB/c male mice were exposed to 50 or 200 ppm benzene vapor, 6 hr/day for 7 or 14 consecutive days. T and B lymphocytes, in blood and spleen, were detected by the cytotoxicity assay with anti-Thy-1.2 monoclonal antibody and the membrane immunofluorescence test with anti-immunoglobulin antibody, respectively. Humoral immune response to sheep red blood cells was determined by the hemolytic plaque-forming cell assay. Cell-mediated immune response was measured by contact sensitivity (CS) to picryl chloride. The activity of suppressor cells was evaluated in spleen by the suppressive effect on passive transfer of CS. The ratio and absolute number of T and B lymphocytes in blood and spleen were depressed after a 7-day exposure at 50 ppm benzene. The depression of B lymphocytes was dose dependent and more intense than that of T lymphocytes. The ability to form antibodies was suppressed by benzene at all exposure levels, but the CS response was resistant to benzene inhalation and rather enhanced at 200 ppm exposure for 14 days. The activity of suppressor cells could not be detected at this dose level. These data show that benzene inhalation effects on humoral and cell-mediated immune responses are a result of the selective toxicity of benzene to B lymphocytes and suppressor T cells.

Nicotinamide-N-methyltransferase is higher in the lumbar cerebrospinal fluid of patients with Parkinson's disease

Parkinson's disease (PD) may be initiated or precipitated by endogenous toxins with a structure similar to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in genetically-predisposed individuals. Nicotinamide N-methyltransferase (NNMT) catalyzes N-methylation of nicotinamide and other pyridines to form pyridinium ions. The protein amount of NNMT was measured in the lumbar cerebrospinal fluid of PD patients by immunoblot analysis using anti-human NNMT antibody. In younger (65 years old or younger) PD patients, the relative level of NNMT protein was significantly higher than that in younger controls. The NNMT protein was significantly affected by aging: the amount decreased along with aging in PD patients. These findings suggested that excess NNMT in the central nervous system might be implicated in the PD pathogenesis.

The triple airway manoeuvre for insertion of the laryngeal mask airway in paralyzed patients

The efficacy of the triple airway manoeuvre (mouth opening, head extension and jaw thrust) for insertion of the laryngeal mask airway (LMA) was compared with the standard insertion method. One hundred paralyzed patients were allocated randomly into two groups: in the control group (n = 50) the LMA was inserted by the standard method, and in the other (TAM group, n = 50) by the triple airway manoeuvre. In ten patients of each group, the position of the LMA and the epiglottis was assessed radiographically before insertion, after insertion but before cuff inflation, and after cuff inflation. In all patients the position was examined using fibrescopy before and after cuff inflation. The mean distance between the epiglottis and the posterior pharyngeal wall, measured radiographically before LMA insertion, was greater in the TAM group (16.3 (SD 4.3) mm) than in the control group (7.0 (2.8) mm) (P < 0.001). Before cuff inflation, radiography and fibrescopy showed that the LMA compressed the epiglottis downwards more frequently in the control group. After cuff inflation the glottis was completely visible fibreoptically in 66% in the TAM group, compared with 14% in the control group (P < 0.001). Complete downfolding of the epiglottis was seen in 10% in the control group and none in the TAM group (P < 0.05). We conclude that in paralyzed patients LMA insertion with the triple airway manoeuvre provides wider pharyngeal space and decreases the incidence of epiglottic downfolding by the LMA compared with the standard method.

Spy1, a histidine-containing phosphotransfer signaling protein, regulates the fission yeast cell cycle through the Mcs4 response regulator

Common histidine-to-aspartate (His-to-Asp) phosphorelay signaling systems involve three types of signaling components: a sensor His kinase, a response regulator, and a histidine-containing phosphotransfer (HPt) protein. In the fission yeast Schizosaccharomyces pombe, two response regulators, Mcs4 and Prr1, have been identified recently, and it was shown that they are involved in the signal transduction implicated in stress responses. Furthermore, Mcs4 appears to be involved in mitotic cell-cycle control. However, neither the HPt phosphotransmitter nor His kinase has been characterized in S. pombe. In this study, we identified a gene encoding an HPt phosphotransmitter, named Spy1 (S. pombe YPD1-like protein). The spy1(+) gene showed an ability to complement a mutational lesion of the Saccharomyces cerevisiae YPD1 gene, which is involved in an osmosensing signal transduction. The result from yeast two-hybrid analysis indicated that Spy1 interacts with Mcs4. To gain insight into the function of Spy1, a series of genetic analyses were conducted. The results provided evidence that Spy1, together with Mcs4, plays a role in regulation of the G(2)/M cell cycle progression. Spy1-deficient cells appear to be precocious in the entry to M phase. In the proposed model, Spy1 modulates Mcs4 in a negative manner, presumably through a direct His-to-Asp phosphorelay, operating upstream of the Sty1 mitogen-activated protein kinase cascade.

Positive pressure ventilation during fibreoptic intubation: comparison of the laryngeal mask airway, intubating laryngeal mask and endoscopy mask techniques

BACKGROUND

The efficacy of delivery of mechanical ventilation through different airway devices during fibreoptic intubation is not known.

METHODS

We compared the laryngeal mask airway (LMA), intubating laryngeal mask (ILM) and endoscopy mask for positive pressure ventilation (PPV) during fibreoptic intubation. In 80 adult paralysed patients, fibreoptic intubation was performed during PPV using a combination of a size 3 or 4 LMA with a 6.0 mm nasal RAE tracheal tube (LMA3/4 group; n=22), a size 5 LMA with a 7.0 mm nasal RAE tube (LMA5 group; n=18), an ILM with an 8.0 mm special reinforced tracheal tube (ILM group; n=20) or an endoscopy mask (Patil mask) with a 7.5 mm standard tracheal tube (Patil group; n=20). The inspiratory and expiratory tidal volumes (VI and VE) with a ventilation pressure of 20 cm H2O were measured using a pneumotachograph.

RESULTS

Mean VE values during fibreoptic intubation in the LMA5 [5.3 (SD 1.5) ml kg(-1)] and ILM [7.1 (2.3) ml kg(-1)] groups were greater than in the LMA3/4 group [2.6 (1.0) ml kg(-1), P<0.0001]. The mean VE was greater in the Patil group [20.6 (4.9) ml kg(-1)] than in the other three groups (P<0.0001). Gastric insufflation during intubation was more frequent in the Patil group (30%) than in the other three groups (4.5-5.6%) (P<0.05).

CONCLUSION

PPV is possible with the LMA, ILM or endoscopy mask during fibreoptic intubation. With an airway pressure of 20 cm H2O, ventilation during intubation using a size 3 or 4 LMA was almost insufficient, while ventilation using a size 5 LMA or an ILM was almost acceptable. Ventilation during intubation with the endoscopy mask was greater than that with the LMA or ILM, but gastric insufflation was more frequent.

Hormonal regulations of glucose-6-phosphate dehydrogenase and lipogenesis in primary cultures of rat hepatocytes

In primary cultured monolayer hepatocytes of adult rats, insulin (1 x 10(-8) M) induced glucose-6-phosphate dehydrogenase [EC 1.1.1.49, G6PDH] several fold in 48 h. It also induced lipogenesis, measured as [1-14C]acetate incorporation in 2 h, in these cells. Of the various lipids, triglycerides and phospholipids were induced markedly, while cholesterol and its esters were not induced. The increase of G6PDH and lipogenesis were parallel. Glucagon, dibutyryl cyclic AMP, triiodothyronine, dexamethasone, epinephrine, isoproterenol, and dibutyryl cyclic GMP were also tested under similar conditions, but none of them caused significant induction of G6PDH or lipogenesis. Use of anti-G6PDH serum showed that induction of G6PDH by insulin was due to increase in the amount of enzyme protein. Insulin was found to increase the rate of synthesis of G6PDH about 3-fold. SDS-polyacrylamide gel electrophoresis of the immunoprecipitable protein revealed that besides G6PDH another radioactive fraction (Mr 37,000) was increased by insulin. This suggests that complete synthesis of G6PDH protein is slowed down in primary cultured hepatocytes and that an apparent nascent peptide of the enzyme accumulates. Although on long-term treatment (48 h), glucagon and dibutyryl cyclic AMP had no effect on lipogenesis, when added with [14C]acetate for 2 h they strongly inhibited lipogenesis. Significant inhibition of lipogenesis by short-term treatment with glucagon was seen even in cells with a high capacity for lipogenesis induced by long-term treatment with insulin. Insulin again stimulated lipogenesis in short-term treatment, but its effect was slight. It is concluded from these results that insulin exerts long-term stimulation of lipogenesis by inducing enzymes related to lipogenesis including G6PDH as well as causing slight stimulation by enhancing supply of substrate for lipogenesis. Glucagon seems to play a minor role in long-term control, but it causes short-term inhibition of lipogenesis.

N-methylation ability for azaheterocyclic amines is higher in Parkinson's disease: nicotinamide loading test

The discovery of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) leads to the hypothesis that Parkinson's disease (PD) is may be initiated or precipitated by endogenous toxins by the mechanism similar to that of MPTP in genetically-predisposed individuals. The higher cerebrospinal fluid levels of N-methylated azaheterocyclic amines, such as beta-carboline and tetrahydroisoquinoline, have been found in parkinsonian patients compared with age-matched controls. To estimate the N-methylation ability for azaheterocyclic amines in parkinsonian patient, nicotinamide was dosed with 100 mg to 26 parkinsonians and 20 controls consisted of 16 other neurogenic disease patients and 4 healthy volunteers. The urine was collected for 4 h, and then analyzed urinary its metabolites by an improved HPLC method. Nicotinamide has a pyridine ring in its structure and may be metabolized through the pathways similar to those for the endogenous neurotoxins. The urinary excretions of nicotinamide metabolites were significantly affected by aging. The excretion of N1-methylnicotinamide decreased along with aging both in PD patients and controls. In younger (65 years old or younger) PD patients, the excretion amount of N1-methylnicotinamide was significantly higher than that in younger controls. The decline rate of N1-methylnicotinamide excretion in parkinsonians was significantly greater than that in controls; the rate is more than 2-fold higher in parkinsonian patients. The age-associated decrease in 1-methyl-2-pyridone-5-carboxyamide excretion was observed only in parkinsonian patients, but not in controls. The total excreted amount of N-methylated metabolites (N1-methylnicotinamide plus 1-methyl-2-pyridone-5-carboxyamide) was also observed the age-related decline in both groups. The urinary excretions of nicotinamide and nicotinamide-N-oxide were not influenced by aging. These results would indicate that the excess N-methylation ability for azaheterocyclic amines before the onset had been implicated in PD. On the other hand, the present results suggested that the contribution of aberrant cytochrome P450 or aldehyde oxidase activity acting on the pyridine ring, that could act as detoxification routes of endogenous neurotoxins, would be small in the etiology of PD.

Molecular cloning and characterization of a novel dual specificity phosphatase, LMW-DSP2, that lacks the cdc25 homology domain

A novel dual specificity phosphatase (DSP) designated LMW-DSP2 was cloned with a combination of reverse transcription-polymerase chain reaction and cDNA library screening strategies. The LMW-DSP2 open reading frame of 194 amino acids contained a single DSP catalytic domain but lacked the cdc25 homology domain, which is conserved in most known DSPs. Northern blot and reverse transcription-polymerase chain reaction analyses revealed that LMW-DSP2 was specifically expressed in testis. Recombinant LMW-DSP2 protein exhibited phosphatase activity toward an artificial low molecular weight substrate para-nitrophenyl phosphate, and the activity was inhibited completely by sodium orthovanadate but not sodium fluoride, pyrophosphate, and okadaic acid. The substitution of critical amino acid residues, aspartic acid and cysteine, resulted in a dramatic reduction of phosphatase activity. Transient transfection of LMW-DSP2 in COS7 cells resulted in the expression of a 21-kDa protein, and the phosphatase was shown to be distributed in both the cytosol and the nucleus. LMW-DSP2 dephosphorylated and deactivated p38, to a higher extent, and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases, in transfected COS7 cells and in vitro. Interestingly, mutation in a conserved docking motif of p38 and SAPK/JNK as well as in a cluster of aspartic acids of LMW-DSP2 did not affect the deactivation of the mitogen-activated protein kinases by LMW-DSP2. Furthermore, the binding between LMW-DSP2 and p38 and SAPK/JNK was also not disrupted by such mutations. Among the DSPs lacking the cdc25 homology domain, LMW-DSP2 is the first one that dephosphorylates and deactivates p38 and SAPK/JNK.

Biochemical studies on liver functions in primary cultured hepatocytes of adult rats. III. Changes of enzyme activities on cell membranes during culture

When liver cells were dispersed with collagenase, their 5'-nucleotidase activity decreased to half the initial level, but it increased to the original level again on culture of the cells for a few days. The activity of another membrane enzyme, alkaline phosphatase, did not decrease on dispersion of the cells, but it increased about 10-fold on culture of the cells. These inductions did not require any hormone, but the effects were greater at a high cell density. These enzymes are located in both the plasma membranes and the cytoplasm, but the enzymes in these two locations can be distinguished by differences in their pH optima, substrate specificities, and susceptibilities to inhibitors. The increases were found to be due to increases in the activity of only the enzymes in the plasma membranes. The increases in enzyme activities were inhibited by actinomycin D, cycloheximide, and puromycin. The activities of leucine aminopeptidase and aminopeptidase B, other membrane enzymes, remained constant during dispersion and culture of the cells. These results show that enzymes in the cell membranes are affected in different ways by cell dispersion with collagenase and subsequent culture of the cells.

Chemical structure and biological activity of a lipid A component from Helicobacter pylori strain 206

The chemical structure of a lipid A, which was obtained as a minor component from lipopolysaccharide of Helicobacter pylori strain 206-1, was determined to be a glucosamine beta-(1 -6) disaccharide 1-(2-aminoethyl)phosphate acylated by (R)-3-hydroxyoctadecanoic acid, (R)-3- hydroxyhexadecanoic acid, and (R)-3-(octadecanoyloxy)octadecanoic acid at the 2-, 3- and 2'-positions, respectively. Compared with the other major lipid A from the same strain, which was previously reported [Suda Y, Ogawa T, Kashihara W et al. Chemical structure of lipid A from Helicobacter pylori strain 206-1 lipopolysaccharide. J Biochem 1997; 121: 1129--1133], the structure was very similar with one exception. An (R)-3-hydroxyhexadecanoic acid was present at the 3-position of the novel lipid A component. The structure is apparently identical to one of the proposals by Moran et al. [Moran AP, Lindner B, Walsh EJ. Structural characterization of the lipid A component of Helicobacter pylori rough- and smooth-form lipopolysaccharides. J Bacteriol 1997; 179: 6453--6463], who concluded the same structure as the so-called major lipid A from the H. pylori strain NCTC 11637 but without isolating a homogeneous component. The endotoxic properties and pro-inflammatory cytokine-inducing activities of this novel tetra-acyl type lipid A were lower than those of previously reported major tri-acyl type lipid A.

A method for 2D crystallization of soluble proteins at liquid-liquid interface

Two-dimensional crystals of soluble proteins were formed at the interface between an aqueous solution of proteins and a thin organic liquid (dehydroabietylamine). Proteins were adsorbed to the interface from the aqueous side and formed a two-dimensional crystal under suitable conditions. This method offers the advantage of great surface mobility and ideal homogeneity. Furthermore, the positive charge attracted negatively charged proteins well to the interface and no denaturation of the proteins was observed. With this technique, two-dimensional crystals of ferritin, catalase, chaperonin and 50S ribosome were prepared and their structural features were determined.

Aging and oxidative stress in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder, which may possibly be induced by oxidative stress. However, the age-related alteration of the endogenous antioxidant system is not well understood. To better understand this, we measured Cu/Zn-superoxide dismutase (SOD), glutathione peroxidase (GPx), and 4-hydroxynonenal (HNE)-conjugated GPx in cerebrospinal fluid of PSP patients by enzyme linked immunosorbent assay. A significant increase in the Cu/Zn-SOD level was detected in PSP group compared with controls. The levels of Cu/Zn-SOD and GPx in PSP group showed positive correlations with age. Two-thirds of total GPx was present as the HNE-conjugated form with positive correlation in PSP group. In conclusion, the endogenous antioxidant system of PSP patients appears to be activated with aging, however, it might be unable to function effectively because of conjugation with HNE.

Complete nucleotide sequence and characterization of a cryptic plasmid from Lactobacillus helveticus subsp. jugurti

A small cryptic plasmid, pLJ1, was isolated from Lactobacillus helveticus subsp. jugurti and was cloned into Escherichia coli HB101 by using pBR329 as a vector. Plasmid pLJ1 was 3,292 base pairs long and had single restriction endonuclease sites for PvuII, KpnI, AvaII, Acci, HindIII, and EcoRI. In a maxicell system, pLJ1 produced a protein of about 41 kilodaltons.