Biomedical subjects

Y Toh

Publications and source records attributed to Y Toh.

At least 73 records · Page 4Linked to original sources

PubMed1993

Candidate metastasis-associated genes of the rat 13762NF mammary adenocarcinoma.

Differential hybridization was used to isolate genes potentially involved in the process of metastasis. Ten complementary DNAs (cDNAs) that were differentially expressed between a highly metastatic (MTLn3) and a nonmetastatic (MTC.4) line of the rat 13762NF mammary adenocarcinoma were isolated and sequenced. Examination of the EMBL/GenBank database revealed that one of the genes had a high degree of homology (98.8%) to annexin I (also known as calpactin II). Quantitative analysis of Northern blot hybridizations showed that the annexin I-like sequence was expressed 4- to 7-fold higher in MTLn3 than in MTC.4 cells. Steady state mRNA levels were also low in MTLn2, a cell line of low metastatic potential closely related to MTLn3, but were not related to metastatic potential in colon adenocarcinoma or melanoma cells. Two of the cDNAs (designated 8.11 and 10.14) were found to be novel. The expression of 10.14 mRNA (3.2 kb) was 4-fold higher in MTLn3 than in MTC.4 cells. Sequencing of the 10.14 cDNA (2.2 kb) revealed a putative open reading frame of 583 amino acids that was also novel. Expression of 8.11 mRNA (> 7 kb) inversely correlated with metastatic potential. Another differentially transcribed gene was highly homologous to ERK2 (extracellular signal related kinase 2), a mitogen-activated protein kinase (MAPK). Northern analysis of ERK2 expression revealed 3-fold higher amounts of a 1.3 kb mRNA in MTLn3 than in MTC.4 cells. Higher levels of ERK2 mRNA were generally seen in the more metastatic human colon but not in melanoma cell lines. We also corroborated the work of Taniguchi (Nucl Acids Res 19:6949, 1991) by independently identifying EF-1 alpha as a putative metastasis-associated gene.

Adenocarcinoma↗

PubMed1993

Necrotizing chorioretinitis in mice inoculated with herpes simplex virus type 1 with or without glycoprotein C: anterior chamber-associated immune deviation does not persist.

BALB/c mice developed contralateral necrotizing retinitis following intracameral inoculation with herpes simplex virus type 1 (HSV-1). The animals showed a positive delayed-type hypersensitivity (DTH) response at 10 days postinoculation, indicating that the anterior chamber-associated immune deviation was transient after HSV-1 inoculation. Since glycoprotein C (gC) of HSV-1 is a major immunogen, we examined DTH and the antibody response induced by a gC-deficient strain TN-1 and compared them with those induced by the recombinant gC-positive mutants. We found that gC was not required for DTH reaction, and that gC was neither necessary for nor protective against the contralateral retinal necrosis. Serial lymphocyte subset analyses of the draining lymph nodes revealed an absolute increase of B cells, CD4-positive T cells, and CD8-positive T cells. CD4-positive T cells but not CD8-positive T cells increased in the contralateral eyes during the inflammation and necrosis. The coincident emergence of the positive DTH and contralateral retinal necrosis of HSV-1-inoculated mice, together with the presence of CD4-positive cells in the retina, indicated that CD4-positive T cells responsible for DTH induction may participate in the retinal necrosis.

Animals↗

PubMed1993

Induction of bilateral retinal necrosis in mice by unilateral intracameral inoculation of a glycoprotein-C deficient clinical isolate of herpes simplex virus type 1.

Herpes simplex virus can cause acute retinal necrosis, a blinding retinal disease in man. A unilateral intracameral inoculation of herpes simplex virus type 1 (HSV-1) in mice induces retinal necrosis primarily in the contralateral eye and provides an experimental model for the disease. Previous studies suggested that a major envelope glycoprotein of HSV-1, glycoprotein C (gC), is required for retinal necrosis. We studied HSV-1 strain TN-1, a gC-deficient clinical isolated from a lesion of herpetic keratitis, for its pathogenicity in mice with an intracameral inoculation of the virus and found that TN-1 could induce severe necrotizing retinitis in both inoculated and uninoculated eyes of BALB/c mice. Inoculation with a lower dose of TN-1 resulted in a unilateral necrotizing retinitis in the uninoculated eyes. Tissue virus titration of infected mice killed at various times after inoculation detected an infectious virus in various organs including the eyeballs, trigeminal ganglia, brain and adrenal glands. Anterior chamber-associated immune deviation (ACAID) was observed in TN-1-inoculated mice as well as in mice inoculated with gC-positive laboratory strain KOS 7 days postinoculation. Our findings suggested that gC of HSV-1 is not necessary for either the induction of retinal necrosis, neural spread of the virus, or ACAID.

Adrenal Glands↗

PubMed1993

Molecular characterization of naturally occurring glycoprotein C-negative herpes simplex virus type 1.

We previously isolated glycoprotein C (gC)-negative herpes simplex virus type 1 (HSV-1) mutants, TN-1, TN-2 and TN-3, from a patient with recurrent herpetic keratitis at one-year intervals. In the present study, the molecular basis for the inability of these clinical isolates to express gC was examined. The nucleotide sequence of the gC gene of the TN-1 strain was compared with that of the HSV-1 KOS strain. In the open reading frame of the gC gene, there were 12 nucleotide differences between the TN-1 and KOS strains, seven of which led to amino acid substitutions. Importantly, one of them was the codon change from CAG for glutamine at position 280 to TAG for the amber termination codon. Accordingly, the TN-1 strain produced a truncated gC with a predicted molecular weight, which was secreted into the extracellular fluid. These results suggest that this amber mutation in the TN-gC gene results in a premature termination of gC translation and is the cause of the gC-negative phenotype of the TN strains. It is expected that these extremely rare HSV-1 strains will provide us with valuable information concerning the in vivo functions of gC, especially in ocular diseases.

Adult↗

PubMed1993

Nucleotide sequence of the major DNA-binding protein gene of herpes simplex virus type 2 and a comparison with the type 1.

The nucleotide sequence of a region encompassing about 5,200 base pairs (bp) of the left side of the origin of replication in the long unique region of the herpes simplex virus type 2 (HSV-2) has been determined. This region contained the major DNA-binding protein or the infected-cell protein 8 (ICP 8) gene and 5'-part of the counterpart of HSV-1 ICP 18.5 gene. A comparison of the nucleotide sequence of the ICP8 gene between HSV-1 and HSV-2 showed an 89.8% homology. A primer extension analysis for the HSV-2 ICP 8 mRNA showed that the major transcriptional start site was mapped at 315 bp upstream of the initiation codon. A comparison of the predicted functional amino acid sequence of the ICP 8 between HSV-1 and HSV-2 revealed a striking homology (97.2%), the value of which was the highest among those of the other polypeptides encoded by HSV-1 and HSV-2. Some domains, which were shown to be required for the nuclear function, the binding to single-stranded DNA and the nuclear localization were well conserved. In addition, the nucleotide and the functional amino acid sequences of a part of the HSV-2 counterpart of the HSV-1 ICP 18.5 gene were also compared, demonstrating an 88.4% and 95.9% homology, respectively.

Amino Acid Sequence↗

PubMed1993

Molecular analysis of a neurovirulent herpes simplex virus type 2 strain with reduced thymidine kinase activity.

Thymidine kinase (TK) of herpes simplex virus (HSV) has been identified as one of the factors responsible for its virulence. We have previously isolated acyclovir (ACV)-resistant HSV type 2 (HSV-2), strain YS-4 C-1, by simple plaque cloning from a clinical isolate. Although YS-4 C-1 had extremely low TK activity, it retained high virulence in mice. To determine the mechanism of the reduction of TK activity, a molecular analysis of the YS-4 C-1 TK gene was performed. YS-4 C-1 produced TK mRNA, which was indistinguishable both in size and amount from that of wild-type strains. However, the YS-4 C-1 TK had a single amino acid change from serine to asparagine at amino acid residue 182 of the TK polypeptide, which was caused by a single nucleotide mutation. It was situated within a highly conserved region (162-194) and close to the putative nucleoside-binding site (169-177), one of the three active centers of TK. In order to confirm the effect of this missense mutation on both the TK activity and neurovirulence, the mutation was introduced into the TK genes of wild-type strains. Although all the recombinants were altered to ACV-resistant viruses with reduced TK activity, they retained high neurovirulence for mice. Our study thus suggested that this mutant TK, in spite of low activity, might play a role in the neurovirulence of HSV-2.

Acyclovir↗

PubMed1993

Separation of large and small granules from horseshoe crab (Tachypleus tridentatus) hemocytes and characterization of their components.

We designed a method for separating two types of granules, a smaller (S) but dense and a larger (L) but less dense granule from hemocytes of the horseshoe crab (Tachypleus tridentatus), using continuous sucrose density gradient centrifugation. The isolated L-granules contained at least three clotting factors plus a clottable protein, coagulogen, as the major component. The known anti-lipopolysaccharide factor and 7 additional unknown protein components were also present in the L-granules. Two known natural substrates, Pro-rich protein and 8.6 kDa protein, for limulus transglutaminase [Tokunaga, F., Yamada, M., Miyata, T., Ding, Y.-L., Hiranaga-Kawabata, M., Muta, T., Iwanaga, S., Ichinose, A., & Davie, E.W. (1993) J. Biol. Chem. 268, 252-261] were present in the L-granules. On the other hand, the isolated S-granules contained antimicrobial tachyplesins I and II (17 amino acids in length) as the major component, in addition to 6 unidentified proteins with molecular masses of less than 30 kDa. The structural analyses of tachyplesin analogs indicated that all these peptides of mature form are stored in the S-granules, together with a processing intermediate containing the COOH-terminal Gly-Lys sequence. We also found an Arg-rich protein of 22 kDa and a Leu-rich protein of 30 kDa in S-granules. Based on these observations, we speculate that protein components in L-granules, which probably contain all the factors essential for the limulus clotting system, participate in immobilization of invading microbes and that factors in the S-granules containing tachyplesins contribute to a self-defense system against invaders.

Amino Acid Sequence↗

PubMed1993

Hyperthermo-chemo-radiotherapy for patients with early carcinoma of the esophagus.

Hyperthermia combined with irradiation and chemotherapy (hyperthermo-chemo-radiotherapy) was prescribed pre-operatively for 21 patients with submucosal carcinoma of the esophagus, and its effectiveness was evaluated by a comparison with patients who also had massive submucosal carcinoma, but received no pre-operative treatment (n = 12). There was no difference in the survival rates of these groups (hyperthermo-chemo-radiotherapy group: 3-year survival in 56.6%), but the patients who responded well to the HCR therapy (n = 6) demonstrated better survival rates (3-year survival in 83.3%) than did the patients without any pre-operative treatment (3-year survival in 33.9%). An HCR sensitivity test using the succinate dehydrogenase inhibition test was devised and showed good correlation with the clinical remedial values (the diagnostic specificity was 0.89). An accurate diagnosis of the esophageal lesion and appropriate selection of potentially treatable cases are considered essential for the optimal use of HCR therapy in patients with submucosal carcinoma.

Adult↗

PubMed1993

Long-term results of esophagectomy for early esophageal carcinoma.

In this paper we report on the long-term results achieved in 75 patients with superficial carcinoma of the thoracic esophagus who have been treated since 1965 with esophagectomy at our institute. In three of these patients, the carcinoma was limited to the epithelium (intra-epithelial carcinoma), while in 13 cases it was confined to the mucosa, and in 59 cases to the submucosa. There was no lymph node metastasis in patients with intra-epithelial or mucosal carcinoma, but lymph node involvement was found in 13 (22.0%) of the 59 cases of submucosal carcinoma. The five-year survival rate of patients with intra-epithelial carcinoma and mucosal carcinoma was 100%, which was significantly better than that for carcinoma invading the submucosa (49%). The five-year survival rate for patients with lymph node involvement was only 46%, which was significantly worse than that for patients without lymph node involvement (60%). No recurrence occurred in patients with intra-epithelial carcinoma or mucosal carcinoma, while recurrent disease occurred in 19 (32.2%) of the 59 patients with submucosal carcinoma. Lymph node recurrence and hematogenic recurrence such as lung and bone metastasis were the most frequent developments in patients with submucosal carcinoma of the esophagus.

Adult↗

PubMed1993

Endoscopic ultrasonography in the diagnosis of an early esophageal carcinoma.

Patients with epithelial or mucosal carcinoma of the esophagus are considered to have a much better prognosis than those with submucosal carcinoma, although both lesions are classified as superficial carcinomas of the esophagus. With this in mind, we evaluated the usefulness of endoscopic ultrasonography for pre-operatively distinguishing either epithelial or mucosal carcinoma from submucosal carcinoma by comparing the results of endoscopic ultrasonography with the histological findings established in resected specimens. Between 1987 and 1991, 26 patients with no pre-operative treatment were confirmed histologically to have epithelial (2 cases), mucosal (11 cases) or submucosal (13 cases) carcinomas of the esophagus. In 13 patients with epithelial or mucosal carcinoma, 10 were correctly diagnosed with endoscopic ultrasonography (76.9%), while the remaining 3 were overdiagnosed as being submucosal. In 13 patients with submucosal carcinoma, 12 were correctly diagnosed by endoscopic ultrasonography (92.3%), although another case was overestimated. Including one patient with an advanced carcinoma who was underdiagnosed by endoscopic ultrasonography as having a submucosal lesion, the overall accuracy of endoscopic ultrasonography was 81.5% for diagnosing the depth of invasion of a superficial esophageal carcinoma. The above results show that endoscopic ultrasonography can provide surgeons with important information in the pre-operative assessment of a superficial esophageal carcinoma.

Adult↗

PubMed1993

Histopathology of early esophageal carcinoma and squamous epithelial dysplasia.

To examine the histogenesis of esophageal cancer and the pathological relationship between dysplasia and carcinoma of the esophagus, 44 cases of superficial esophageal carcinoma (restricted to within the submucosal layer) who received no pre-operative treatment were reviewed retrospectively. There were 40 dysplastic lesions in 17 cases (38.6%) and epithelial dysplastic lesions were classified into 6 with mild, 17 with moderate and 17 with severe, degrees of dysplasia. Although the continuity of dysplastic lesions with the carcinomatous areas was not frequent (35.0%), it was more often encountered in severe dysplasia than in moderate or mild dysplasia, suggesting some relationship between the severity of dysplasia and carcinoma. In the cases with a dysplastic lesion, multiplicity of squamous cell carcinoma was more frequently seen (p < 0.01), suggesting a multicentric occurrence of dysplastic lesions and carcinomas.

Adult↗

PubMed1993

Mediastinal drainage prevents fatal pyothorax from anastomotic leakage after intrathoracic anastomosis in reconstruction for carcinoma of the esophagus.

In our experience, anastomotic leakage occurred in five of 69 patients with intrathoracic anastomosis after resection of carcinoma of the esophagus. In the early period, only an ordinary right thoracic drain was put in place, and when leakage occurred, two patients died because of pyothorax, while one patient was saved by surgical drainage. However, in the recent period, in addition to the ordinary right thoracic drain, another drain has also been placed just distal to the anastomosis through the esophageal hiatus through the abdominal cavity, exiting the abdominal wall. After such procedure, drainage has been adequate without any occurrence of pyothorax, even when anastomotic leakage occurred, as in the two most recent instances. Therefore, unless drainage is inadequate and surgical drainage is indicated, as in instances of necrosis of substitutes, mediastinoabdominal drainage seems to be effective in the treatment of intrathoracic anastomotic leakage.

Aged↗

PubMed1992

Detection of human papillomavirus DNA in esophageal carcinoma in Japan by polymerase chain reaction.

BACKGROUND: Human papillomaviruses (HPV) have been implicated strongly in the pathogenesis of human squamous cell carcinomas, especially of anogenital carcinomas. Some pathologic changes of the esophagus may be one of the candidates for HPV etiology, but the role of HPV infections in the carcinogenesis of the esophagus remains to be clarified. METHODS: To elucidate the association of HPV with carcinogenesis of the esophagus, 45 biopsy samples of esophageal squamous cell carcinomas were examined for the presence of HPV DNA by polymerase chain reaction (PCR). Primers for PCR were (1) consensus primers (CP) for the simultaneous amplification of the E6-E7 regions of cancer-associated HPV types (HPV 16, 18, 31, 33, 52b, and 58), which have been shown to have transforming activities; (2) type-specific primers (SP16, SP18) for the E7 regions of HPV 16 and HPV 18, respectively; and (3) general primers (GP) for the simultaneous amplification of the L1 regions of HPV 6, 11, 16, 18, 31, and 33. RESULTS: PCR using CP first was done for screening and showed that 3 (6.7%) of 45 specimens contained HPV 16 or HPV 18 DNA, the oncogenic high-risk HPV types. This was confirmed by SP16 and SP18 PCR. However, no HPV DNA was detected by PCR using GP. These results suggested that the HPV DNA detected might be integrated into the cell genome with their transforming genes retained and their late regions deleted. CONCLUSIONS: Most oncogenic types of HPV (HPV 16 and HPV 18) were detected by PCR in carcinomas of the esophagus. Thus, HPV might play a role, although at a low frequency, in carcinogenesis of the esophagus.

Base Sequence↗

PubMed1992

Reactivation of cytomegalovirus in patients with cirrhosis: analysis of 122 cases.

Human cytomegalovirus causes severe and often fatal infections in immunocompromised patients. After organ transplantation cytomegalovirus in peripheral blood mononuclear cells is thought to be activated by alloreaction and to spread because of immunosuppression, and it may cause endogenous cytomegalovirus diseases. Patients with cirrhosis, one group of candidates for liver transplantation, often show various grades of immunosuppression before transplantation. To evaluate the status of cytomegalovirus infection in cirrhotic patients and its relevance to the degree of immunosuppression, we examined the presence of cytomegalovirus in mononuclear cells by polymerase chain reaction and immunocytochemical analysis. We studied 122 patients with definite cirrhosis and 43 normal volunteers. All cirrhotic patients (100%) and 40 (93%) of 43 normal controls were seropositive for cytomegalovirus. Cytomegalovirus DNA was detected by polymerase chain reaction in 77 (63.1%) of 122 seropositive cirrhotic patients, but in only 1 (2.5%) of 40 seropositive normal controls (p < 0.01). Cytomegalovirus antigen could not be detected in mononuclear cells by immunocytochemical staining with monoclonal antibodies. Cytomegalovirus DNA-positive patients have a greater impairment of liver function than do cytomegalovirus DNA-negative patients; this fact is manifested by delayed indocyanine green retention rates and elevated serum bilirubin levels (p < 0.05). Lymphocyte proliferative response induced by phytohemagglutinin and natural killer cell activity were also significantly lower in cytomegalovirus DNA-positive patients as compared with cytomegalovirus DNA-negative patients (p < 0.01). Our data suggest that the reactivation of cytomegalovirus may have already occurred in patients with cirrhosis before transplantation.

Adult↗

PubMed1992

Synergistic effects of intratumor administration of cis-diamminedichloroplatinum(II) combined with local hyperthermia in melanoma bearing mice.

The synergistic effect of local hyperthermia (LHT) with intratumor injection (i.t.) of cis-diamminedichloroplatinum (II) (DDP) was studied using a rodent model with implanted B16 melanoma tumors. The hindfoot of the C57BL/6 mouse bearing the tumor was placed in a water bath at 42.5 +/- 0.2 degrees C (intratumor temperature was at 42.3 +/- 0.1 degrees C) for 30 minutes just after local (i.t.) or systemic (intraperitoneal;i.p.) administration of DDP (1-3 mg/kg once in experiment I and 1-3 mg/kg three times in experiment II). The tumor growth ratio (TGR) at 7 days after treatment in the group given DDP 3 mg/kg (i.t.) with LHT was 1.1 in experiment I and 0.5 in experiment II, and there was a statistically significant difference in both experiments compared to findings in other groups (P < 0.01). The mean survival time was 42.1 days in experiment I and 50.2 days in experiment II, with a significant difference in the latter (P < 0.001). Thus regional injection chemotherapy given concomitantly with local hyperthermia promotes the anticancer effects and improves the prognosis without either severe renal injury or the promotion of hematogenic metastasis.

Animals↗

PubMed1992

Possible role of cytomegalovirus in the pathogenesis of inflammatory aortic diseases: a preliminary report.

To search for possible evidence of a relationship between human cytomegalovirus and aortic diseases, we examined 41 aortic lesions excised at surgery and 16 aortic tissues obtained at autopsy for the presence of cytomegalovirus DNA, by use of polymerase chain reaction. Cytomegalovirus DNA was present in seven (88%) of eight lesions of inflammatory aortic diseases with periaortic fibrosis, five of six inflammatory aneurysms, and all of two aortic occlusive lesions with inflammation. Cytomegalovirus DNA was detected in 20 (61%) of 33 atherosclerotic aneurysms, whereas it was detected in only five (31%) of 16 autopsy samples that showed neither inflammation nor atherosclerosis. Thus the possibility that cytomegalovirus may play a role in the pathogenesis of inflammatory aortic diseases warrants further attention.

Adult↗

PubMed1991

Limulus factor C. An endotoxin-sensitive serine protease zymogen with a mosaic structure of complement-like, epidermal growth factor-like, and lectin-like domains.

Factor C is an endotoxin-sensitive, intracellular serine protease zymogen which initiates the coagulation cascade system in the limulus hemolymph. We have determined the entire amino acid sequence of factor C using recombinant DNA technique. The zymogen consisted of 994 amino acid residues with a calculated molecular mass of 109,648 Da. Most interestingly, factor C has five repeating units ("Sushi" domain or short consensus repeat) of about 60 amino acid residues each, which have been found in many proteins participating in the mammalian complement system. In addition to a typical serine protease domain in the carboxyl-terminal portion, characteristic segments with an epidermal growth factor-like, a lectin-like, a cysteine-rich, and a proline-rich domain were also found, revealing a unique mosaic protein structure. The serine protease domain was most analogous to human thrombin. Factor C was identified to localize in large granules in the cell, indicating that it is released from the cell by lipopolysaccharide stimulation. Furthermore, we identified a transcript possibly derived by alternative splicing of factor C mRNA, which encodes a protein sharing the amino-terminal portion of factor C. We suggest that factor C, a newly discovered type of serine protease zymogen, is a "coagulation-complement factor" which may play important roles in both hemostasis and host defense mechanisms.

Amino Acid Sequence↗

PubMed1991

Gastropericardial and gastrobrachiocephalic vein fistulae caused by penetrating ulcers in a gastric pedicle following esophageal cancer resection: a case report.

The gastric pedicle is commonly used for reconstruction following resection of esophageal cancer. However, we recently experienced a case in which two gastric tube ulcers occurred three months postoperatively; one penetrating into the pericardial cavity and the other into the left brachiocephalic vein. To our knowledge, no other such a case has ever been reported and we therefore report and discuss its etiology and management.

Aged↗