Biomedical subjects

H Kitagawa

Publications and source records attributed to H Kitagawa.

At least 109 records · Page 6Linked to original sources

PubMed1999

Synaptic excitability of the burst firing neurons in cat sensorimotor cortex in vitro.

We have recently reported that the burst firing neurons are found in layer III as well as in layer V of cat sensorimotor cortex in vitro. In the present study, we examined the synaptic excitability of layer III neurons by white matter stimulation and compared with their firing patterns against the current injections through the recording microelectrodes. The firing patterns of layer III neurons were classified into three main classes as in our previous study, i.e., (1) regular spiking (RS), i.e., the tonic firing that often exhibited spike-frequency adaptation, (2) burst-and-single spiking (BS), i.e., the initial bursting followed by tonic firing, (3) repetitive-bursting (RB), the burst firing that recurred at fast frequency. In RS cells, single action potential was superimposed on the largest EPSPs among all cell types analyzed. BS cells also fired single action potential and never exhibited burst firing synaptically. Only in a part of RB cells, synaptic bursting instead of single action potential was evoked on smaller EPSPs. IPSPs could be observed in about 60% of all the recorded RS and BS cells, however, they were observed in only 10% of the RB cells.

Animals↗

PubMed1999

Effects of terfenadine, astemizole and epinastine on electrocardiogram in conscious cynomolgus monkeys.

We examined the effects of non-sedative histamine H1 receptor antagonists on the electrocardiogram (ECG) in conscious cynomolgus monkeys. Terfenadine (3 mg kg(-1) h(-1), i.v.) and astemizole (0.3 and 1 mg kg(-1) h(-1), i.v.) caused significant time-dependent increases in the QT interval and QTc Bazett (QTc). However, normal ECG forms were found during a 60-min infusion of epinastine (3 mg kg(-1) h(-1) i.v.). A higher dose of epinastine (10 mg kg(-1) h(-1), i.v.) increased the QTc and PR interval only 5 min after the start of the infusion. The minimum plasma concentrations of terfenadine, astemizole and epinastine which caused QTc prolongation were 85, 35 and over than 3600 ng/ml, respectively. These drugs did not alter the PQ and QRS intervals and did not cause arrhythmia or atrioventricular block. Our results are consistent with the clinical observation that prolongation of QTc is caused by terfenadine and astemizole but not by epinastine. Thus, measurement of QTc in cynomolgus monkey appears to be a useful approach for evaluating the potential cardiotoxicity of histamine H1 receptor antagonists.

Animals↗

PubMed1999

Induction of glial cell line-derived neurotrophic factor receptor proteins in cerebral cortex and striatum after permanent middle cerebral artery occlusion in rats.

In an attempt to elucidate whether glial cell line-derived neurotrophic factor (GDNF) receptors are induced after ischemic brain injury, possible expression of immunoreactive GDNF receptor-alpha1 (GFRalpha-1) and c-ret (RET) was examined at 3, 8, or 24 h after permanent middle cerebral artery occlusion (MCAO) in rats. Immunohistochemical study showed that both GFRalpha-1 and RET staining cells which were not detected in sham control brain, were present in the ipsilateral cortex and caudate at 3 to 8 h after permanent MCAO, and then decreased but remained to some extent at 24 h. Positive cells for both GDNF receptors were predominantly in cortical neurons of ischemic penumbral area. Western blot analysis confirmed the induction of those receptors after permanent MCAO. This rapid induction of GFRalpha-1 and RET, which correlates with the similar induction of GDNF under these conditions, may play a role in the early response to ischemic brain injury.

Animals↗

PubMed1999

Epinastine, a nonsedating histamine H1 receptor antagonist, has a negligible effect on HERG channel.

Terfenadine and astemizole rarely cause cardiac arrhythmias by suppressing the cardiac rapid delayed rectifier K+ channel encoded by the human ether-a-go-go-related gene (HERG). Epinastine, however, has not been reported to have the adverse effect. We have therefore compared the effects of epinastine, terfenadine and astemizole on HERG channels expressed in Xenopus oocytes. Terfenadine and astemizole suppressed the HERG current with IC50 of 431 nM and 69 nM, respectively. In contrast, 100 microM epinastine inhibited the HERG current by only 11+/-2.1%. These results may provide an explanation for the difference in the cardiotoxicity between different nonsedating histamine H1 receptor antagonists.

Animals↗

PubMed1999

Involvement of the core protein in the first beta-N-acetylgalactosamine transfer to the glycosaminoglycan-protein linkage-region tetrasaccharide and in the subsequent polymerization: the critical determining step for chondroitin sulphate biosynthesis.

alpha-Thrombomodulin (alpha-TM) with a truncated glycosaminoglycan-protein linkage tetrasaccharide, GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl, was tested as an acceptor together with a sugar donor, UDP-N-[3H]acetylgalactosamine, using a cell-free enzyme system prepared from the serum-free culture medium of a human melanoma cell line. The truncated tetrasaccharide on alpha-TM served as an acceptor, whereas the linkage tetrasaccharide-serine did not. Our characterization of the radioactively labelled product by enzymic digestion revealed that the N-[3H]acetylgalactosamine residue was transferred to alpha-TM through a beta1,4-linkage. The substrate competition experiments with the chondro-hexasaccharide and alpha-TM reinforced our speculation that a common N-acetylgalactosaminyltransferase catalysed the transfer of N-acetylgalactosamine to both the linkage tetrasaccharide and the longer chondroitin oligosaccharides. Moreover, chondroitin polymerization was demonstrated on the tetrasaccharide of alpha-TM using both UDP-glucuronic acid and UDP-N-acetylgalactosamine as sugar donors. Much longer chains were synthesized on alpha-TM than on the linkage penta- and hexa-saccharide-serines. Together, these results indicated that the core protein is required for the transfer of the first N-acetylgalactosamine residue through a beta1,4-linkage and also for subsequent efficient chain polymerization reactions, and that the critical determining step for chondroitin sulphate biosynthesis is the transfer of the first N-acetylgalactosamine residue.

Acetylgalactosamine↗

PubMed1999

The tumor suppressor EXT-like gene EXTL2 encodes an alpha1, 4-N-acetylhexosaminyltransferase that transfers N-acetylgalactosamine and N-acetylglucosamine to the common glycosaminoglycan-protein linkage region. The key enzyme for the chain initiation of heparan sulfate.

We previously demonstrated a unique alpha-N-acetylgalactosaminyltransferase that transferred N-acetylgalactosamine (GalNAc) to the tetrasaccharide-serine, GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser (GlcA represents glucuronic acid), derived from the common glycosaminoglycan-protein linkage region, through an alpha1,4-linkage. In this study, we purified the enzyme from the serum-free culture medium of a human sarcoma cell line. Peptide sequence analysis of the purified enzyme revealed 100% identity to the multiple exostoses-like gene EXTL2/EXTR2, a member of the hereditary multiple exostoses (EXT) gene family of tumor suppressors. The expression of a soluble recombinant form of the protein produced an active enzyme, which transferred alpha-GalNAc from UDP-[3H]GalNAc to various acceptor substrates including GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser. Interestingly, the enzyme also catalyzed the transfer of N-acetylglucosamine (GlcNAc) from UDP-[3H]GlcNAc to GlcAbeta1-3Galbeta1-O-naphthalenemethanol, which was the acceptor substrate for the previously described GlcNAc transferase I involved in the biosynthetic initiation of heparan sulfate. The GlcNAc transferase reaction product was sensitive to the action of heparitinase I, establishing the identity of the enzyme to be alpha1, 4-GlcNAc transferase. These results altogether indicate that EXTL2/EXTR2 encodes the alpha1,4-N-acetylhexosaminyltransferase that transfers GalNAc/GlcNAc to the tetrasaccharide representing the common glycosaminoglycan-protein linkage region and that is most likely the critical enzyme that determines and initiates the heparin/heparan sulfate synthesis, separating it from the chondroitin sulfate/dermatan sulfate synthesis.

Acetylgalactosamine↗

PubMed1999

Anti-P-selectin antibody attenuates rat brain ischemic injury.

We examined a protective effect of anti-P-selectin monoclonal antibody against rat ischemic brain injury with 24 h of middle cerebral artery occlusion (MCAO). Anti-rat P-selectin monoclonal antibody, was intravenously injected at a dose of 1 mg/kg at 5 min before MCAO. Control animals received the same volume of vehicle. MCAO was accomplished by an insertion of nylon thread with silicone coating for 24 h. Application of anti-P-selectin antibody significantly reduced infarct size and brain water content at 24 h of MCAO. Although leukocyte infiltration was not normally detected, it became remarkably evident at 1 day of MCAO. However, treatment with ARP 2-4 significantly reduced the number of leukocytes. These results demonstrated that administration of monoclonal antibody against P-selectin attenuated infarct size and brain edema, which was associated with reduction of leukocyte infiltration.

Animals↗

PubMed1999

Activation of stress-activated protein kinase/c-Jun NH2-terminal kinase and p38 kinase in calphostin C-induced apoptosis requires caspase-3-like proteases but is dispensable for cell death.

Apoptosis was induced in human glioma cell lines by exposure to 100 nM calphostin C, a specific inhibitor of protein kinase C. Calphostin C-induced apoptosis was associated with synchronous down-regulation of Bcl-2 and Bcl-xL as well as activation of caspase-3 but not caspase-1. The exposure to calphostin C led to activation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) and p38 kinase and concurrent inhibition of extracellular signal-regulated kinase (ERK). Upstream of ERK, Shc was shown to be activated, but its downstream Raf1 and ERK were inhibited. The pretreatment with acetyl-Tyr-Val-Ala-Asp-aldehyde, a relatively selective inhibitor of caspase-3, or benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD.fmk), a broad spectrum caspase inhibitor, similarly inhibited calphostin C-induced activation of SAPK/JNK and p38 kinase as well as apoptotic nuclear damages (chromatin condensation and DNA fragmentation) and cell shrinkage, suggesting that caspase-3 functions upstream of SAPK/JNK and p38 kinase, but did not block calphostin C-induced surface blebbing and cell death. On the other hand, the inhibition of SAPK/JNK by transfection of dominant negative SAPK/JNK and that of p38 kinase by SB203580 induced similar effects on the calphostin C-induced apoptotic phenotypes and cell death as did z-VAD.fmk and acetyl-Tyr-Val-Ala-Asp-aldehyde, but the calphostin C-induced PARP cleavage was not changed, suggesting that SAPK/JNK and p38 kinase are involved in the DNA fragmentation pathway downstream of caspase-3. The present findings suggest, therefore, that the activation of SAPK/JNK and p38 kinase is dispensable for calphostin C-mediated and z-VAD.fmk-resistant cell death.

Amino Acid Chloromethyl Ketones↗

PubMed1999

Analysis of paraaortic lymph node involvement in pancreatic carcinoma: a significant indication for surgery?

BACKGROUND: Lymph node status is a key prognostic factor for pancreatic carcinoma. The paraaortic lymph nodes are the highest level of lymph nodes that can be resected safely in the abdomen for pancreatic and other gastrointestinal tumors. The pattern of paraaortic lymph node involvement and its relation with other lymph node groups were analyzed and the significance of this information relative to surgical therapy examined. METHODS: Between 1974-1996, 99 patients with invasive ductal carcinoma of the pancreas underwent pancreatectomy at the study institution. The pattern of lymph node involvement, particularly paraaortic, was evaluated by careful pathologic review of extended lymphadenectomy specimens. RESULTS. Fifty-eight of 76 patients (76%) with carcinoma in the pancreatic head (Ph) and 19 of 23 patients (83%) with carcinoma of the pancreatic body and tail (Pbt) had lymph node involvement. Fourteen patients with Ph disease (18%) and 4 with Pbt disease (17%) had paraaortic lymph node involvement. Tumor size did not correlate with paraaortic lymph node involvement. A correlation was found between Group 13 (posterior pancreaticoduodenal lymph nodes), Group 14 (lymph nodes surrounding the superior mesenteric artery), and the paraaortic lymph nodes for Ph disease. All paraaortic lymph node metastases were located in the 16M region (the region between the celiac trunk and the inferior mesenteric artery). For patients with Pbt disease, the distribution of paraaortic lymph node metastases was the same as for those with Ph disease. Only 33% of cases of paraaortic lymph node metastases were suspected preoperatively or perioperatively. The longest survival for a patient with paraaortic lymph node metastases was 36 months and 17 months, respectively, for patients with Ph and Pbt disease. CONCLUSIONS: The paraaortic lymph nodes are frequent sites of metastasis from pancreatic carcinoma, and are difficult to evaluate preoperatively or perioperatively. This situation mandates paraaortic lymph node dissection, at least in the 16M region.

Adult↗

PubMed1999

Proteasome inhibitors induce mitochondria-independent apoptosis in human glioma cells.

The proteasome inhibitors lactacystin and AcLLNal induced p53-independent apoptosis in two human glioma cell lines, and the apoptosis was accompanied by up-regulation of immunoreactive wild-type p53, p21Waf1, Mdm2, and p27Kip1. Pretreatment with cycloheximide decreased the induction of cell death independently of p53 protein status, suggesting that the up-regulation of short-lived proteins is associated with proteasome inhibitor-induced apoptosis. Caspase-3-like proteases were activated in the proteasome inhibitor-mediated apoptosis, and the induction of cell death was inhibited more effectively in the presence of z-VAD.fmk than in the presence of Ac-DEVD.fmk, suggesting that caspases other than caspase-3 are involved. Nonetheless, there were no significant alterations in levels of immunoreactive Bcl-2, Bcl-X(L), Bax, Bad, and Bak, nor any evidence of cytochrome c release into cytosol and dissipation of delta(psi)m. Thus, the proteasome inhibitor-induced apoptosis is mediated by a mitochondria-independent mechanism, and the once activated caspase-3 does not cause the cytochrome c release and the delta(psi)m disruption.

Animals↗

PubMed1999

Transient mutism resolving into cerebellar speech after brain stem infarction following a traumatic injury of the vertebral artery in a child.

A 3.7-year-old girl presented with an anterior neck injury followed by progressive subcutaneous emphysema and loss of consciousness. After resuscitation, a laceration on the first tracheal cartilage was closed surgically. As she was extubated one week later, she was found to have right hemiplegia and muteness. MRI showed a T2-bright lesion on the tegmentum of the left midbrain down to the upper pons. Right vertebral angiography disclosed an intimal flap with stenosis at the C3 vertebral level presumably caused by a fracture of the right C3 transverse process later confirmed in a cervical 3D-CT scan. Her muteness lasted for 10 days, after which she began to utter some comprehensible words in a dysarthric fashion. Her neurological deficits showed improvement within 3 months of her admission. Transient mutism after brain stem infarction has not been reported previously. We discuss the anatomical bases for this unusual reversible disorder in the light of previous observations and conclude that bilateral damage to the dentatothalamocortical fibers at the decussation of the superior cerebellar peduncle may have been responsible for her transient mutism.

Brain Mapping↗

PubMed1999

The pathogenesis of dysplastic kidney in a urinary tract obstruction in the female fetal lamb.

BACKGROUND/PURPOSE: The type of renal dysplasia resulting from obstructive uropathy depends on the completeness of the obstruction and its timing with respect to the stage of glomerulogenesis at the time of the obstruction. The authors created a successful obstructive uropathy model in the female fetal lamb to demonstrate the differing pathogenesis of renal dysplasia. METHODS: Female fetal lambs at 60 and 90 days' gestation had their urethra and urachus ligated transabdominally and were delivered by cesarean section at 145 days (full term). Kidney length and cortical thickness were measured, and samples were examined histologically. In the lambs operated on at 90 days, the urine was collected at delivery and Na and CI were measured and compared with the results obtained from normal full-term lambs. RESULTS: Seven of 10 female lambs had hydronephrosis or dysplastic kidneys. The cortext to kidney length ratio was 10+/-3% in the 90-days hydronephrotic group versus 29+/-6% in the controls (P<.001). Morphologically, the 90-day model had dilatation of the collecting tubules with normal glomerular numbers. The 60-day model had tubular cysts with fibromuscular cuffing and reduced glomerular numbers. The fetal urine Na was 47+/-3.3 mmol/L in controls versus 78+/-24 mmol/L in the hydropnephrotic lambs (P<.05). The urine CI in these lambs was 38+/-8.6 mmol/L in controls versus 55+/-14.5 mmol/L in the hydronephrotic lambs (P<.05). CONCLUSIONS: An obstructive uropathy model was created in female fetal lambs. There were no dysplastic changes in the kidneys in lambs operated on at 90 days' gestation, but there were definite dysplastic changes in those operated on at 60 days. Concentrations of Na and CI in the fetal urine are higher than normal in the 90-day model.

Animals↗

PubMed1999

Characteristic transport of lactoferrin from the intestinal lumen into the bile via the blood in piglets.

Lactoferrin is a major iron-binding protein in milk from several species, such as humans, monkeys, mice and sows. Using neonatal and weaner piglets, the characteristic transfer of lactoferrin from intestinal lumen into bile via the circulation was investigated. Bovine lactoferrin (1 or 3 g/kg body weight) was infused into the stomach through a polyethylene tube or into the duodenum through a duodenal catheter over 5 min. Peripheral blood and bile samples were collected after the infusion. Lactoferrin absorbed into plasma and bile were assayed quantitatively by double-antibody enzyme-linked immunosorbent assay, and homogeneity of bovine lactoferrin in plasma and bile was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting methods. Morphological investigation was carried out according to the peroxidase anti-peroxidase method. Following oral administration in neonatal pigs, bovine lactoferrin appeared in the blood circulation and reached a peak level after 2 h. It was confirmed immunohistochemically that lactoferrin was transported by endocytosis via the epithelial cells. Lactoferrin absorbed into the blood was also detected in the bile and reached a peak value 12 h after oral administration. Transportation of lactoferrin from the intestinal lumen into the bile via the bloodstream was also observed in weaner piglets. Lactoferrin transported into plasma and bile was confirmed to be the same substance as administrated lactoferrin by electrophoresis and immunoblotting methods. Lactoferrin transported into bile was re-absorbed into the blood in neonatal pigs. These results demonstrate that lactoferrin contained in milk is transported into the circulation from the intestinal lumen and excreted into the bile, suggesting the possibility of entero-hepatic circulation of lactoferrin in neonatal pigs.

Administration, Oral↗

PubMed1999

Effect of icatibant, a bradykinin B2 receptor antagonist, on the development of experimental ulcerative colitis in mice.

Dextran sulfate sodium-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, we carried out a study on the preventive effect of Icatibant, a bradykinin B2 receptor antagonist previously called HOE 140, on the development of colitis. Subcutaneous administration of Icatibant (0.3 or 1.5 mg/kg) significantly suppressed shortening of the large intestine and worsening of the general health. Oral administration of Icatibant (50 mg/kg) significantly suppressed shortening of the large intestine, the onset of diarrhea, and worsening of the general health. In addition, the oral treatment significantly inhibited the development of colitis that was observed histopathologically. These results indicate a role of BK in the development of dextran sulfate sodium-induced colitis in mice, and suggest that BK could be important in human ulcerative colitis.

Administration, Oral↗

PubMed1999

Purification and characterization of fetal bovine serum beta-N-acetyl-D-galactosaminyltransferase and beta-D-glucuronyltransferase involved in chondroitin sulfate biosynthesis.

beta-N-Acetylgalactosaminyltransferase II and beta-glucuronyltransferase II, involved in chondroitin sulfate biosynthesis, transfer an N-acetylgalactosamine (GalNAc) and glucuronic acid (GlcA) residue, respectively, through beta-linkages to an acceptor chondroitin oligosaccharide derived from the repeating disaccharide region of chondroitin sulfate. They were copurified from fetal bovine serum approximately 2500-fold and 850-fold, respectively, by sequential chromatographies on Red A-agarose, phenyl-Sepharose, S-Sepharose and wheat germ agglutinin-agarose. Identical and inseparable chromatographic profiles of both glycosyltransferase activities obtained through the above chromatographic steps and gel filtration suggest that the purified enzyme activities are tightly coupled, which could imply a single enzyme with dual transferase activities; beta-N-acetylgalactosaminyltransferase and beta-glucuronyltransferase, reminiscent of the heparan sulfate polymerase reaction. However, when a polymerization reaction was performed in vitro with the purified serum enzyme preparation under the polymerization conditions recently developed for the chondroitin-synthesizing system, derived from human melanoma cells, each monosaccharide transfer took place, but no polymerization occurred. These results may suggest that the purified serum enzyme preparation contains both beta-N-acetylgalactosaminyltransferase II and beta-glucuronyltransferase II activities on a single polypeptide or on the respective polypeptides forming an enzyme complex, but is different from that obtained from melanoma cells in that it transfers a single GalNAc or GlcA residue but does not polymerize chondroitin.

Animals↗

PubMed1999

Reduction of ischemic brain injury by anti-P-selectin monoclonal antibody after permanent middle cerebral artery occlusion in rat.

The selectin family of adhesion molecules is involved in adhesion of leukocyte to microcirculatory system and the transmigration into brain parenchyma. Although the role of P-selectin may be important in the pathogenesis of brain ischemia, a possible protective effect on ischemic brain injury by blocking P-selectin has not been reported. We have examined the effects of a novel anti-P-selectin antibody on ischemic brain injury after 24 h of permanent middle cerebral artery occlusion (MCAO) in rat. Male Wistar rats were subjected to MCAO by an insertion of a silicone rubber cylinder for 24 h. Anti-rat P-selectin monoclonal antibody, ARP 2-4, was injected intravenously at a dose of 1 mg kg-1 at 5 min before the induction of MCAO. Control animals received the same volume of vehicle solution. Regional cerebral blood flow (rCBF) was measured immediately after and at 8 h of MCAO. At decapitation of rats at 24 h of permanent MCAO, infarct size was compared between the antibody and vehicle treated group. In addition, immunohistochemistry for leukocyte infiltration and HSP72, and histochemistry for TUNEL were also, compared. Pretreatment with ARP 2-4 improved rCBF at 8 h of MCAO (55.4% +/- 11.7% of control, n = 5) as compared to vehicle group (24.2% +/- 11.8%, n = 5, p < 0.02). Although leukocyte infiltration was not normally detected by monoclonal antibodies for CD11a and CD18, it became remarkably evident at 1 day of MCAO. Although HSP72 and TUNEL were not also detected in sham control brains, they were induced in neurons of the MCA area at 1 day of MCAO. Treatment with ARP 2-4 significantly reduced the numbers of leukocyte and neurons with positive HSP72 and TUNEL stainings. These results demonstrated that an administration of a monoclonal antibody against P-selectin improved rCBF, and attenuated infarct size that was associated with reduction of leukocyte infiltration. Furthermore, treatment with the antibody reduced both HSP72 and TUNEL stainings. These data suggest an important role of P-selectin in ischemic brain damage, and a future therapeutic potential to human stroke patients.

Animals↗

PubMed1999

Identification and characterization of a novel UDP-GalNAc:GlcAbeta-R alpha1,4-N-acetylgalactosaminyltransferase from a human sarcoma cell line.

We recently discovered a novel alpha-N-acetylgalactosaminyltransferase in fetal bovine serum (Kitagawa et al., J. Biol. Chem., 270, 22190-22195, 1995) and also in mouse mast cytoma cells (Lidholt et al., Glycoconjugate J., 14, 737-742, 1997), which catalyzed the transfer of an alpha-GalNAc residue to the linkage tetrasaccharide-serine, GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser, derived from proteoglycans. In this study, we characterized this enzyme using a preparation obtained from the serum-free culture medium of a human sarcoma (malignant fibrous histiocytoma) cell line by phenyl-Sepharose chromatography. Structural characterization by1H NMR spectroscopy of the reaction product using the linkage tetrasaccharide-serine, GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser, as a substrate demonstrated that the enzyme was a UDP-GalNAc:GlcAbeta1-R alpha1,4-N -acetylgalactosaminyltransferase. This is the first identification of an alpha1,4-N-acetylgalactosaminyltransferase. Using N -acetylchondrosine GlcAbeta1-3GalNAc as an alternative substrate, the enzyme required divalent cations for the transferase reaction, with maximal activity at 20 mM Mn2+and exhibited a dual optimum at pH 6.5 and pH 7.4 depending upon the buffers used, with the highest activity in a 50 mM 2-( N -morpholino)ethanesulfonic acid buffer at pH 6.5. The apparent Km values obtained for N -acetylchondrosine, the linkage tetrasaccharide-serine, and UDP-GalNAc were 1060 microM, 188 microM, and 27 microM, respectively. This suggested that the linkage tetrasaccharide-serine was a good acceptor substrate for the enzyme. In addition, the enzyme utilized glucuronylneolactotetraosylceramide GlcAbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4G lcbeta1-1Cer but not sulfoglucuronylneolactotetraosylceramide GlcA(3-O -sulfate)beta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Gl cbeta1-1Cer as acceptor substrates. The possibility of involvement of this enzyme in the biosynthesis of glycosaminoglycan as well as other GlcA-containing glycoconjugates is discussed.

Animals↗

PubMed1999

Role of nodal involvement and the periductal soft-tissue margin in middle and distal bile duct cancer.

OBJECTIVE: To determine the pattern of middle (Bm) and distal (Bi) bile duct cancers in an attempt to optimize surgical treatment. SUMMARY BACKGROUND DATA: Lymph node involvement and neural plexus invasion are the prognostic factors most amenable to surgery in Bm and Bi disease. However, a detailed analysis of these factors has not been conducted. METHODS: Fifty patients with Bm and Bi disease (Bm 14 patients, Bi 36 patients) were examined histopathologically. A precise determination was made of lymph node involvement and neural plexus invasion. Important prognostic factors were examined by clinicopathologic study to apply these findings to surgical management. RESULTS: Frequencies of nodal involvement for Bm and Bi disease were 57% and 71%, respectively. The inferior periductal and superior pancreaticoduodenal lymph nodes were most commonly involved. Neural plexus invasion occurred in 20% of patients, particularly involving the plexus in the hepatoduodenal ligament and pancreatic head. Tumor was present at the surgical margin in 50% and 14% of patients with Bm and Bi disease, respectively. Five-year survival rates were 65% in the absence of nodal metastasis and 21% with nodal metastasis. A significant correlation existed between absence of tumor at the surgical margin and survival. A Cox proportional hazard model projected absence of tumor at the surgical margin, followed by nodal involvement, as the strongest prognostic variables. CONCLUSIONS: Absence of tumor at the surgical margin and nodal involvement are important independent prognostic factors in Bm and Bi disease. Skeletonization of the hepatoduodenal ligament, including portal vein resection, is necessary for patients with Bm disease, and a wide nodal dissection is essential in all patients.

Adult↗