[An approach to operative treatment for acute abdomen complicated by malignant hemopathy]

The experience of operative treatment in 14 cases of acute abdomen complicated by malignant hemopathy was reported. Primary diseases consisted of AL, NHL, MM, MH and MDS-RA, 13 cases of them were at progressing stage. The acute abdominal conditions included acute appendicitis, acute pancreatitis, acute cholecystitis, peritonitis secondary to intestinal perforation, intestinal obstruction, primary peritonitis and ileocecal syndrome. The type of acute abdomen was related with primary desease and chemotherapy. 8 cases were operated and 2 of them died of complications after operation. Biopsy of excised tissue showed tumor cells in 2 cases. The rate of correllation between preoper active and postoperative diagnosis was 62.5%. These findings suggest that malignant infiltration in the viscera, duration of abdominal pain before operation and the change of blood picture are the major factors for determining operative indication and the postoperative prognosis.

[Optimization of non-gel sieving capillary electrophoretic separation of DNA fragments of hundreds of base pairs]

Non-gel sieving capillary electrophoresis has been employed in the biological sciences for the size-based separation of macromolecules such as nucleic acids. In this paper, four factors i.e. electric field strength, capillary length, capillary diameter and hydroxy-propylmethylcellulose (HPMC) concentration were integratively evaluated to select the optimal condition of separating DNA fragments of a few hundreds of base pairs through orthogonal analysis. Conclusion was made through comprehensive analysis: better separation could be achieved in longer capillary, smaller inside diameter of capillary and less field strength. In practical application, effective separation in short time is important. We preferred to employ 8 g/L HPMC in coated capillary (37 cm x 75 microns i.d.) and electric field strength of 324 V/cm in separating DNA fragments of hundreds of base pairs. From sampling to getting results only a few more than ten minutes were needed in capillary electrophoresis. It needs less amount of sample (a few nanoliters) and shows higher sensitivity (0.1 pmol in UV detection) than polyacrylamide gel electrophoresis (PAGE). pBR322/Msp I fragments were completely resolved in both capillary electrophoresis and PAGE, and four-bases resolution was obtained. When the concentration of the PCR product is too low (< 20 mg/L), PCR reaction system is used as a negative control to make sure of the peak generated by the unpurified PCR products, avoiding interference made by PCR buffer and polymerase.

A secretory cellulose-binding protein cDNA cloned from the root-knot nematode (Meloidogyne incognita)

A cDNA encoding a secretory cellulose-binding protein was cloned from the root-knot nematode (Meloidogyne incognita) with RNA fingerprinting. The putative full-length cDNA, named Mi-cpb-1, encoded a 203 amino acid protein containing an N-terminal secretion signal peptide. The C-terminal sequence of the putative MI-CBP-1 was similar to a bacterial-type cellulose-binding domain, whereas the N-terminal sequence did not show significant similarity to any proteins in data bases. Recombinant MI-CBP-1 lacked cellulase activity, but bound to cellulose and plant cell walls. In Southern blot hybridization, Mi-cbp-1 hybridized with genomic DNA from M. incognita, M. arenaria, and M. javanica, but not M. hapla, Heterodera glycines, or Caenorhabditis elegans. Polyclonal antibodies raised against recombinant MI-CBP-1 strongly labeled secretory granules in subventral gland cells of second-stage juveniles in indirect immunofluorescence microscopy. Enzyme-linked immunosorbent assay detection of MI-CBP-1 in stylet secretions of second-stage juveniles with the polyclonal antibodies indicated MI-CBP-1 could be secreted through the nematodes' stylet, suggesting that the cellulose-binding protein may have a role in pathogenesis.

Identification and characterization of a novel tissue-specific transcriptional activating element in the 5'-flanking region of the CYP2A3 gene predominantly expressed in rat olfactory mucosa

CYP2A3 is expressed preferentially in rat olfactory mucosa and is believed to play important roles in maintaining cellular homeostasis in the chemosensory tissue. DNase I footprinting analysis revealed a single protected region in the proximal promoter of the CYP2A3 gene with nuclear extracts from olfactory mucosa, but not from liver, lung, kidney, or brain. The core sequence of the binding site, named the nasal predominant transcriptional activating (NPTA) element, is similar to that of nuclear factor 1, but it interacted with unique proteins detected only in the olfactory mucosa in electrophoretic mobility shift assays or on Southwestern blots. The NPTA element is conserved in rat CYP2A3, mouse Cyp2a5, and human CYP2A6 genes and was found to be essential for transcriptional activity of the CYP2A3 promoter in in vitro transcription assays. NPTA-binding proteins were detectable at day 1 and were much more abundant at day 8 than at day 60 after birth. Furthermore, their levels decreased dramatically during chemically induced degeneration of the olfactory epithelium, paralleling the disappearance of CYP2A3 protein, and rebounded to higher than pretreatment levels during recovery. Thus, we have identified a novel transcriptional activation element potentially responsible for the olfactory mucosa-predominant expression of the CYP2A3 gene in rats and orthologous genes in mice and humans.

GB virus C/hepatitis G virus infection among Colombian native Indians

To elucidate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection in Colombian native Indians, serum GBV-C/HGV RNA was assayed in 163 native Indians and 67 members of the general population in Colombia. The native Indians (males:females = 40:123) and the members of the general population (males:females = 20:47) were tested by reverse transcription-semi-nested polymerase chain reaction. Of the 163 native Indians, 10 (6.1%) were positive for GBV-C/HGV RNA, compared with one (1.5%) of 67 from the general population. All Indians were negative for hepatitis B surface antigen and antibody to hepatitis C virus. Of 10 Indians with GBV-C/HGV RNA, the genotype of nine subjects was the Asian type. These data indicated that 1) the prevalence of GBV-C/HGV RNA in Colombian native Indians is high, and 2) GBV-C/HGV was probably brought from Asia and inherited for generations in some native Indian groups.

Insulin secretion is inhibited by subtype five somatostatin receptor in the mouse

BACKGROUND

Recently five somatostatin receptor subtypes (SSTRs) were cloned, allowing the development of highly specific agonists to these SSTRs. Previous studies have shown a species specificity phenomenon with respect to the inhibition of insulin secretion by these selective agonists. This study was undertaken to determine which SSTR (2 or 5) is responsible for the inhibitory effect of somatostatin on glucose-stimulated mouse insulin secretion.

METHODS

Intact mouse islets (n = 10) were stimulated with D-glucose in the presence or absence of receptor-specific somatostatin agonists.

RESULTS

D-glucose (16.7 mmol/L) augmented insulin secretion by 158% above that seen with 3.9 mmol/L D-glucose. In the presence of DC 32-92 (SSTR5) selective agonist, D-glucose (16.7 mmol/L) augmented insulin secretion by 64% above that seen with 3.9 mmol/L D-glucose. The presence of SSTR 5 selective agonist resulted in a significant (P < .05) inhibition of glucose-stimulated insulin secretion. The identification of SSTR5 within the mouse pancreas was established by reverse transcriptase polymerase chain reaction and confirmed by Southern blot analysis.

CONCLUSIONS

These results suggest that the inhibitory effect of somatostatin on insulin secretion is mediated through the subtype 5 receptor within the mouse islet.

[Investigation of the genetic instability of tumor cells by transfection of RER+ cell lines with exogenous microsatellite sequence]

OBJECTIVE

Frequent alterations of microsatellite sequence of cancer cells were found recently in a substantial fraction of human cancers including hereditary non-polyposis colon cancer. This paper aimed to investigate the genetic instability of tumor cells by using microsatellite instability(MI) as the marker in vitro.

METHODS

Two RER+ cell lines (replication error phenotype), RKO and HCT116 and one RER- cell line, sw480, were used as the hosts for transfection with an episomal plasmid, pCMV-CAR, containing an exogenous (CA)14 repeat which was inserted within the coding sequence of lacZ reporter gene and thus made lacZ misreading. The transfectant clones were selected and established by hygromicin. Expression and production of lacZ reporter gene of restored reading frame were detected with X-gal staining assay.

RESULTS

After hygromicin selection, stable pCMV-CAR transfectant clones were established. It was shown that mutation of deletion of insertion within(CA)14 occurred in the transfectant RER+ cells but not in the RER-cells. The mutation restored normal reading frame of lacZ gene, and resulted in expression and production of bio-active beta galactosidase which was detected with X-gal staining. This feature of the transfectant clones was maintained during culture passages.

CONCLUSION

The alterations of the exogenous(CA)14 repeat in the transfectant RER+ clones revealed genetic instability and complicated mutation status of cancer cells. It is suggested that the exogenous (CA)14 in transfectant clones could be a useful target sequence for monitoring the effects of environmental agents on MI of human cancer cells.

Differential xenobiotic induction of CYP2A5 in mouse liver, kidney, lung, and olfactory mucosa

The effects of pyrazole, which is known to induce hepatic cytochrome P4502A5 (CYP2A5) through posttranscriptional mechanisms, on the level of CYP2A5 in liver and extrahepatic tissues were examined in this study. Intraperitoneal administration of pyrazole at 200 mg/kg for 3 days induced CYP2A4/5 mRNAs and proteins and microsomal coumarin 7-hydroxylation activity in liver and kidney of C57BL/6 mice. A marginal increase (30%) in CYP2A4/5 mRNAs was also observed in the olfactory mucosa but not in the lung, and no increase in CYP2A4/5 proteins or microsomal coumarin 7-hydroxylation activity was observed in either the olfactory mucosa or lung. CYP2A4/5 proteins were not detected on immunoblots in other tissues examined, including breast, bone marrow, testis, prostate, ovary, and uterus from control or pyrazole-treated mice. On the other hand, pyrazole treatment induced CYP2E1 in the olfactory mucosa as well as in liver and kidney, indicating that the olfactory mucosa was exposed to pyrazole. The lack of CYP2A inducibility in the olfactory mucosa was also observed for several other known inducers of hepatic CYP2A5, including cobaltous chloride, stannous chloride, griseofulvin, thioacetamide, and aminotriazole. These results suggest that the mechanisms involved in the induction of hepatic and renal CYP2A5 by pyrazole and other xenobiotic compounds may be tissue-specific.

Structure of the metal-ion-activated diphtheria toxin repressor/tox operator complex

The virulent phenotype of the pathogenic bacterium Corynebacterium diphtheriae is conferred by diphtheria toxin, whose expression is an adaptive response to low concentrations of iron. The expression of the toxin gene (tox) is regulated by the repressor DtxR, which is activated by transition metal ions. X-ray crystal structures of DtxR with and without (apo-form) its coordinated transition metal ion have established the general architecture of the repressor, identified the location of the metal-binding sites, and revealed a metal-ion-triggered subunit-subunit 'caliper-like' conformational change. Here we report the three-dimensional crystal structure of the complex between a biologically active Ni(II)-bound DtxR(C102D) mutant, in which a cysteine is replaced by an aspartate at residue 102, and a 33-base-pair DNA segment containing the toxin operator toxO. This structure shows that DNA interacts with two dimeric repressor proteins bound to opposite sides of the tox operator. We propose that a metal-ion-induced helix-to-coil structural transition in the amino-terminal region of the protein is partly responsible for the unique mode of repressor activation by transition metal ions.

[Analysis of 25 episodes of acute occupational poisoning accidents and studies on its preventive strategy]

OBJECTIVE

To study the causes of the occurrence of severe acute occupational poisoning and its first-aid, and to improve its prevention and management.

METHODS

Data of labor health conditions in 25 episodes of poisoning during the past 13 years were collected and analyzed statistically according to industries, enterprises and toxicals.

RESULTS

Twenty-five episodes of poisoning accidents involved 131 persons, with 22 deaths. The incidence rate of occupational poisoning accidents in township and town enterprises exceeded that in state-owned ones. Ten kinds of toxicants were involved in the poisoning, with the hydrogen sulfide, benzene, carbon monoxide, phosgene and organophosphorus pesticide at the top five places in the number of cases with poisoning they caused. There were another 131 persons intoxicated during their emergency action and eight deaths, with a higher incidence and mortality rates due to poisoning than those in the operation workers.

CONCLUSION

The major causes of the poisoning accidents were lack of knowledge of prevention and protection from them. It laid a good foundation for the establishment of emergency rescuing system in the grassroots.

Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects

Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1x10(12)ions/cm2. The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed.

[Expression of p53 and ras p21 gene products in malignant transformed V79 cell induced by various organic components of DEPs]

The effect of various fractions of diesel exhausted particles on the expression of mutant p53 antigen product and ras oncogene p21 product was examined by immunohistochemical method in malignant transformed V79 cell. The result showed that all fractions of diesel exhausted particles (DEPs) could significantly increase the expression of p53 products (P < 0.01). It demonstrated that the organic fractions of DEPs could induce the mutation of p53 suppressor gene in malignant transformed cells. But the expression levels of ras oncogene p21 product were not changed under the same experimental conditions (P > 0.05).

[Chemical constituents of Phyllanthus urinaria L. and its antiviral activity against hepatitis B virus]

Studies on the chemical constituents of Phyllanthus urinaria and its antiviral activity against hepatitis B virus were completed. Eleven compounds have been isolated. Two of them are new compounds methyl ester dehydrochebulic acid and methyl brevifolin carboxylate. Antiviral experiments on HBsAg in vitro and liver damage caused by CCl4 have shown that. Phyllanthus urinaria possesses antiviral activities against HBV.

Purification and characterization of heterologously expressed mouse CYP2A5 and CYP2G1: role in metabolic activation of acetaminophen and 2,6-dichlorobenzonitrile in mouse olfactory mucosal microsomes

The metabolic activation of two known olfactory mucosal (OM) toxicants, acetaminophen (AP) and 2,6-dichlorobenzonitrile (DCBN), was examined with mouse liver and OM microsomes and purified, heterologously expressed mouse CYP2A5 and CYP2G1. In reconstituted systems, both isoforms were active in metabolizing DCBN and AP to metabolites that formed protein adducts. The formation of DCBN- or AP-protein adducts and other AP metabolites, including 3-hydroxy-AP and, in the presence of glutathione, AP-glutathione conjugate, was also detected in OM microsomal reactions and to a much greater extent than in liver microsomes. Evidence was obtained that CYP2A5 and CYP2G1 play major roles in mouse OM microsomal metabolic activation of DCBN and AP. Immunoblot analysis indicated that CYP2A5 and CYP2G1 are abundant P450 isoforms in OM microsomes. OM microsomal AP and DCBN metabolic activation was inhibited by 5- and 8-methoxsalen, which inhibit both CYP2A5 and CYP2G1, and by an inhibitory anti-CYP2A5 antibody that also inhibits CYP2G1. In addition, the roles of CYP1A2 and CYP2E1 in the OM bioactivation of AP and DCBN were ruled out by comparing activities of acetone-treated mice or Cyp1a2(-/-) mice with those of control mice. Thus, CYP2A5 and CYP2G1 may both contribute to the known OM-selective toxicity of AP and DCBN. Further analysis of the kinetics of AP and DCBN metabolism by the purified P450s suggested that CYP2A5 may play a greater role in OM microsomal metabolism of AP, whereas their relative roles in DCBN metabolism may be dose dependent, with CYP2G1 playing more important roles at low substrate concentrations.

Role of CYP2A5 and 2G1 in acetaminophen metabolism and toxicity in the olfactory mucosa of the Cyp1a2(-/-) mouse

Acetaminophen (AP) is a widely-used analgesic agent that has been linked to human liver and kidney disease with prolonged or high-dose usage. In rodents, the target organs that are affected include liver, kidney, and the olfactory mucosa. AP toxicity requires cytochrome P450(CYP)-mediated metabolic activation, and the isozymes CYP1A2, 2E1, and 3A are known to activate AP in the human. In the present study, we determined that olfactory mucosal toxicity of AP was not different between the Cyp1a2(+/+) wild-type and the Cyp1a2(-/-) knockout mouse, whereas the hepatic toxicity of AP was significantly diminished in Cyp1a2(-/-) mice. Western blots of olfactory mucosa revealed that CYP2E1 and CYP3A levels are similar between untreated Cyp1a2(+/+) and Cyp1a2(-/-) mice. Diallyl sulfide (DAS), a known inhibitor of CYP2E1 and of CYP2A10/2A11 (the rabbit orthologue of mouse CYP2A5), completely eliminated olfactory toxicity of AP in both the Cyp1a2(-/-) and wild-type mouse olfactory mucosa. We found that heterologously expressed mouse CYP2A5 and CYP2G1 enzymes (known to be present in olfactory mucosa) form 3-hydroxyacetaminophen (3-OH-AP) and 3-(glutathion-S-yl)acetaminophen (GS-AP); CYP2A5 is considerably more active than 2G1. Addition of GSH caused increases in GS-AP proportional to decreases in 3-OH-AP, suggesting that these two metabolites arise from a common precursor or are formed by way of competing pathways. We also found that both CYP2A5 and CYP2G1 are inhibitable by DAS in vitro. These studies provide strong evidence that, in addition to CYP2E1, CYP2A5 and 2G1 are important in AP bioactivation in the mouse olfactory mucosa and that CYP1A2 appears to be of minor importance for AP olfactory toxicity.

Characterization of the cytochrome P450 CYP2J4: expression in rat small intestine and role in retinoic acid biotransformation from retinal

The sites of expression in the small intestine and the function of CYP2J4, a recently identified rat cytochrome (P450) isoform found to be predominantly expressed in the small intestine, were characterized. Immunoblot analysis with a polyclonal antibody to heterologously expressed CYP2J4 revealed that expression of CYP2J4 was at the highest level in the distal duodenum and jejunum and decreased toward the ileum. Villous cells expressed higher levels of CYP2J4 than crypt cells. Isoform-specific RNA polymerase chain reaction indicated that a related P450 isoform, CYP2J3, was only a minor form in rat small intestine. Since the intestinal mucosa is exposed to high levels of dietary nutrients, we hypothesized that CYP2J4 may be active toward diet-derived factors. We determined that purified, heterologously expressed CYP2J4 is active toward all-trans- and 9-cis-retinal in reconstituted systems, producing the corresponding retinoic acids as the major products. Apparent K(m) values for the formation of retinoic acids were 54 and 49 microM, respectively, and apparent Vmax values were 20 and 21 nmol/min/nmol P450, respectively. These activities were readily inhibited by a polyclonal anti-CYP2J4 antibody. Rat enterocyte microsomes were also active with all-trans-retinal to produce all-trans-retinoic acid in the presence of NADPH, and the majority of retinoic acid synthesis activity was inhibited by the polyclonal anti-CYP2J4 antibody. These findings suggest that CYP2J4 plays a major role in intestinal microsomal metabolism of retinal to retinoic acid and may be involved in the maintenance of retinoid homeostasis in the small intestine in vivo.

Insect resistance of transgenic tobacco expressing an insect chitinase gene

Chitinase expression in the insect gut normally occurs only during moulting, where the chitin of the peritrophic membrane is presumably degraded. Thus, insects feeding on plants that constitutively express an insect chitinase gene might be adversely affected, owing to an inappropriately timed exposure to chitinase. This hypothesis was tested by introducing a cDNA encoding a tobacco hornworm (Manduca sexta) chitinase (EC 3.2.1.14) into tobacco via Agrobacterium tumefaciens-mediated transformation. A truncated but enzymatically active chitinase was present in plants expressing the gene. Segregating progeny of high-expressing plants were compared for their ability to support growth of tobacco budworm (Heliothis virescens) larvae and for feeding damage. Both parameters were significantly reduced when budworms fed on transgenic tobacco plants expressing high levels of the chitinase gene. In contrast, hornworm larvae showed no significant growth reduction when fed on the chitinase-expressing transgenics. However, both budworm and hornworm larvae, when fed on chitinase-expressing transgenic plants coated with sublethal concentrations of a Bacillus thuringiensis toxin, were significantly stunted relative to larvae fed on toxin-treated non-transgenic controls. Foliar damage was also reduced. Plants expressing an insect chitinase gene may have agronomic potential for insect control.

Role of corticotropin-releasing factor and substance P in pressor responses of nuclei controlling emotion and stress

The wide distribution of corticotropin-releasing factor (CRF) and substance P (SP)-immunoreactive cell bodies, nerve terminals and corresponding receptors in pressor nuclei controlling emotion and stress implies that CRF and SP may play important roles in pressor responses of these nuclei; hence CRF or SP was microinjected into these nuclei respectively in Wistar male rats anesthetized with urethane to test this possibility. Microinjection of CRF into nucleus amygdaloideus centralis, nucleus paraventricularis, nucleus ventromedialis, lateral hypothalamus-perifornical region, periaqueductal gray matter, nucleus parabrachialis, locus coeruleus or rostral ventrolateral medulla respectively could evoke pressor responses (but CRF injection into nucleus dorsomedialis could not elicit significant pressor responses). Injection of substance P into all the above nuclei could also elicit hypertensive responses of different magnitudes, whereas normal saline injection into these nuclei had no effect. These results indicate that both CRF and SP in the above mentioned nuclei may play important roles in hypertension induced by prolonged emotional stress.

Pancreatic cancer cells selectively stimulate islet beta cells to secrete amylin

BACKGROUND & AIMS

Patients with pancreatic adenocarcinoma have a high incidence of diabetes, profound insulin resistance, and high circulating amylin concentrations. It was hypothesized that pancreatic cancer cells produce a factor that stimulates islets to secrete amylin but not insulin.

METHODS

Amylin and insulin secretion were measured after coculture of pancreatic cancer cells with beta cells (BRIN-BD11). The factor responsible was characterized by exposing beta cells to cancer cell-conditioned medium.

RESULTS

Coculture with pancreatic (PANC-1 HPAF, and MiaPaCa2) but not colonic cancer cells (Colo 320) significantly increased amylin secretion but did not change insulin output. This effect was both time and cell number dependent. Coculture with PANC-1 or HPAF cells significantly decreased intracellular amylin, but not insulin, content. PANC-1 or HPAF cell-conditioned medium also increased amylin secretion and decreased intracellular amylin content. The factor responsible was extracted under both neutral and acidic conditions, was heat labile, and had a molecular weight of approximately 1500.

CONCLUSIONS

A soluble factor from pancreatic cancer cells selectively stimulates amylin secretion from islet cells, explaining the excessive amylin secretion found in pancreatic cancer. Because elevation of amylin concentration is an early feature of pancreatic cancer, characterization and measurement of the tumor-derived amylin-releasing factor might be valuable in the early detection of this disease.

Pre-MBT patterning of early gene regulation in Xenopus: the role of the cortical rotation and mesoderm induction

Patterning events that occur before the mid-blastula transition (MBT) and that organize the spatial pattern of gene expression in the animal hemisphere have been analyzed in Xenopus embryos. We present evidence that genes that play a role in dorsoventral specification display different modes of activation. Using early blastomere explants (16-128-cell stage) cultured until gastrula stages, we demonstrate by RT-PCR analysis that the expression of goosecoid (gsc), wnt-8 and brachyury (bra) is dependent on mesoderm induction. In contrast, nodal-related 3 (nr3) and siamois (sia) are expressed in a manner that is independent of mesoderm induction, however their spatially correct activation does require cortical rotation. The pattern of sia and nr3 expression reveals that the animal half of the 16-cell embryo is already distinctly polarized along the dorsoventral axis as a result of rearrangement of the egg structure during cortical rotation. Similar to the antagonistic activity between the ventral and the dorsal mesoderm, the ventral animal blastomeres can attenuate the expression of nr3 and sia in dorsal animal blastomeres. Our data suggest that no Nieuwkoop center activity at the blastula stage is required for the activation of nr3 and sia in vivo.

Signals regulating accelerated muscle protein catabolism in uremia

In chronic renal failure (CRF), the ATP-dependent, ubiquitin-proteasome proteolytic pathway is activated with concurrent increases in the transcription of genes encoding proteins of this pathway in muscle. We have shown that the stimuli for these responses include acidosis and glucocorticoids, but other endocrine abnormalities in CRF (e.g., insulin resistance) could contribute to these responses. In fact, a major effect of insulin in muscle is to suppress protein degradation. To examine whether insulin influences the ubiquitin-proteasome pathway, we measured protein degradation in incubated epitrochlearis muscles of diabetic and pair-fed control rats. Muscle proteolysis was increased in pathways that do not involve lysosomes or Ca(2+)-dependent proteases; but MG132, a protease inhibitor that blocks ATP synthesis, eliminated the accelerated rate of protein degradation in diabetic rat muscles. Diabetes mellitus also increased levels of mRNAs encoding ubiquitin (334%), E2 ubiquitin-conjugating enzyme (247%), and the C3 (320%), C5 (349%), and C9 (216%) proteasome subunits in muscle. Finally, transcription of the ubiquitin gene in diabetic rat muscles was increased. Diabetic rats were acidotic, but eliminating acidemia by giving NaHCO3 did not block the increase in muscle proteolysis. Giving diabetic rats insulin prevented the excessive muscle proteolysis, suggesting that insulin acts as a suppressor of the ubiquitin-proteasome pathway. Thus, the insulin resistance of uremia could contribute to muscle protein wasting in CRF.

T lymphocytes from a subset of patients with pemphigus vulgaris respond to both desmoglein-3 and desmoglein-1

Pemphigus vulgaris and pemphigus foliaceus are cutaneous autoimmune diseases characterized by intraepithelial blisters and autoantibodies to desmosomal glycoproteins. The antigens recognized by pemphigus vulgaris and pemphigus foliaceus autoantibodies are desmoglein-3 (Dsg3) and desmoglein-1 (Dsg1), respectively. Dsg3 and Dsg1 are members of the desmoglein subfamily of the cadherin supergene family of cell adhesion molecules. It has been well documented that a subset of pemphigus vulgaris sera have IgG reactivity to both Dsg1 and Dsg3, suggesting that Dsg1 may also participate in the autoimmune response of these patients. The cellular mechanisms of T cell autoimmunity in these patients, however, are completely unknown. In this study, we tested the proliferative responses of T lymphocytes from eight pemphigus vulgaris patients after incubation with Dsg3 and Dsg1 fusion proteins. The sera of four of these PV patients showed reactivity with both Dsg1 and Dsg3, whereas the remaining four reacted only with Dsg3. We found that T cells obtained from those patients that exhibited the combined Dsg1/Dsg3 autoantibody reactivity showed a proliferative response after exposure to either Dsg1 or Dsg3 fusion proteins. The cellular responses to both of these recombinant proteins were highly specific and restricted to the CD4-positive T cell population. T cells from pemphigus vulgaris patients with no anti-Dsg1 serum reactivity showed a proliferative response to Dsg3, but not to Dsg1. The Dsg1 fusion protein used in this study has minimal sequence homology with Dsg3. Thus, this study provides the first evidence that T cells from a subset of pemphigus vulgaris patients respond to both Dsg1 and Dsg3.

[Analysis of triacylglycerol composition of perilla oil by combination of non-aqueous reversed-phase high performance liquid chromatography with gas chromatography]

Perilla oil was verified to be a rich source of polyunsaturated fatty acid (PUFA). Its linolenic content is 64.82%, the highest in the plants. Its triacylglycerol (TAG) components were isolated and identified first time in this paper by a combination of non-aqueous reversed-phase high performance liquid chromatography (RP-HPLC) with gas chromatography (GC). The TAG of perilla oil were isolated by HPLC with a Zorbax ODS column (5 microm, 4.6 mm i.d. x 250 mm; Dupont, Inc) and differential refractometer. The eluent was acetone/acetonitrile (80:20, V/V) with flow rate of 1.0 mL/min. The TAG component acyl groups were converted to fatty acid methyl esters (FAME). The acyl constituents for each TAG were determined by GC analysis. Gas chromatography of FAMEs was performed with a AC20 Carbowax 20M column (30 m x 0.32 mm i.d.). Detector and injection port temperatures were 260 degrees C. Column temperature was programmed from 120 degrees C, 1 min initially hold, then 8 degrees C/min to 220 degrees C and finally hold for 10 min. Nitrogen was the carrier gas. FAMEs peaks were identified by comparison of their retention times with those of standards. The retention times of the palmitic, stearic, oleic, linoleic, n-nonadecanoic acid (internal standard) and linolenic FAMEs were 10.7, 13.0, 13.3, 13.8, 14.2 and 14.7 min respectively. Five main components were determined. They were LnLnLn (34.10%), LnLnL (13.22%), LnLL (6.22%), LnLnO (11.38%) and LnLnP (9.17%). The TAG contents were corrected from their fatty acids content. The combination of non-aqueous RP-HPLC with GC is a simple and rapid method for the analysis of oil TAG structure and is also very helpful for the identification of oil quality.