Common phenotypic expression of gangliosides GM3 and GD3 in normal human tissues and neoplastic skin lesions

The expression of gangliosides in non-malignant tissues (epidermis and pigmented nevus) and neoplastic lesions (melanoma, squamous cell carcinoma [SCC] and basal cell carcinoma [BCS]) of the human skin was analyzed immunohistochemically and biochemically to characterize the features associated with malignancy. Immunohistochemical staining with an anti-II3NeuAc-LacCer (GM3) monoclonal antibody (M2590 mAb) and an anti-II3(NeuAc)2-LacCer (GD3) mAb (R24) showed the expression of the gangliosides GM3 and GD3 to vary among the different tissues. M2590 clearly stained epidermal keratinocytes and the tumor cells of BCC and SCC, and strongly stained melanocytes and melanoma cells. In contrast, R24 did not stain epidermal keratinocytes and only faintly stained SCC cells, while it clearly stained BCC cells, and intensely stained melanocytes and melanoma cells. GM3 showed a similar level of staining among the tissue specimens, while the level of GD3 staining was quite variable among the tumor specimens. Biochemical analysis by thin-layer chromatography (TLC) with resorcinol staining and TLC immunostaining with either M2590 or R24 showed both GM3 and GD3 to be commonly expressed by both the normal and malignant skin tissues, including SCC. There was no close correlation between the intensity of immunohistochemical staining and the biochemically detected amounts of these gangliosides. This may have been partly due to the so-called cryptic expression of cell membrane gangliosides. Our results thus suggest that analysis of the tumor-associated expression of gangliosides requires several methods, since the sensitivity of the methods used may have a considerable effect on the diagnostic value of gangliosides as skin cancer markers.

Altered expression of protein kinase C in adult T-cell leukemia cells

Protein kinase C (PKC) has been shown to be involved in the mitogenic response and in oncogenic cell transformation in many experimental models. We analyzed the expression of PKC in both highly purified leukemic T cells freshly isolated from adult T-cell leukemia (ATL) patients and control T lymphocytes obtained from healthy volunteers. PKC activity was decreased in the ATL cells as compared with the control T cells. Cytosolic PKC activity in the ATL cells was remarkably decreased, whereas particulate membrane PKC activity was similar to the control level. The percentage of PKC activity in the particulate fraction was 34% in the ATL cells and 19% in the control cells. Regarding the altered subcellular localization of PKC activity, phorbol ester-induced translocation of cytosolic PKC was inhibited in some ATL cases. Similarly to the decrease in PKC activity, there was a decrease in the expression of the major PKC isozymes II(beta) and III(alpha) in ATL cells. These results suggest impaired regulation of PKC expression in ATL as well as in many experimental cancers.

Inversion of chromosome 16 and bone marrow eosinophilia in a myelomonocytic transformation of chronic myeloid leukemia

We report a case of chronic myeloid leukemia (CML) in myelomonocytic transformation associated with bone marrow (BM) eosinophilia. At diagnosis, all BM cells showed a Ph chromosome. At the time of blastic phase, more than 50% of Ph+ cells had a pericentric inversion of chromosome 16, inv(16)(p13q22). This case confirms that blastic transformation of CML can involve any committed progenitor, and myelomonocytic leukemia with BM eosinophilia is specifically associated with rearrangement of chromosome 16 at band p13 and q22.

Nucleotide sequence of a carboxyphosphonoenolpyruvate phosphonomutase gene isolated from a bialaphos-producing organism, Streptomyces hygroscopicus, and its expression in Streptomyces lividans

The carboxyphosphonoenolpyruvate (CPEP) phosphonomutase gene of bialaphos-producing Streptomyces hygroscopicus, which encodes a C-P bond forming enzyme was cloned into Streptomyces lividans and sequenced. The amino acid composition of the protein coded in an open reading frame of 295 codons and its calculated molecular mass, 32,800 Da, coincided well with those of the purified enzyme. Introduction of the CPEP phosphonomutase gene, the expression of which is controlled by the promoter of the aph gene, into S. lividans resulted in the production of this enzyme at a level almost equivalent to that in the parent strain.

Identification of a site required for DNA replication fork blocking activity in the rRNA gene cluster in Saccharomyces cerevisiae

The yeast genome has DNA replication fork blocking sites, that we have named sog sites, in the ribosomal RNA gene (rDNA) cluster. These are located at the 3' end of the 35S rRNA transcription unit and they block replication fork movement in a direction opposite to that of RNA polymerase I. We cloned this replication blocking site into a YEp-type plasmid and analyzed DNA replication intermediates, using two-dimensional (2D) agarose gel electrophoresis. The blocking activity remained even on a plasmid not involved in 35S rRNA transcription and inhibited fork movement in the same polar fashion as on the yeast chromosome. To define the site further, smaller fragments were subcloned into the YEp-type plasmid. A small 109 bp region exhibited sog activity and was located near the enhancer region for 35S rRNA transcription. It overlaps an essential element of the recombinational hot spot HOT1.

Termination complex in Escherichia coli inhibits SV40 DNA replication in vitro by impeding the action of T antigen helicase

DNA replication terminus (ter)-binding protein (TBP) in Escherichia coli binds specifically to the terminus (ter) site, and the resulting complex severely blocks DNA replication in an unique orientation by inhibiting the action of helicases. To generalize the intrinsic nature of the orientated ter-TBP complex against various helicases, we tested the potential of the complex to inhibit the action of three helicases, DNA helicase I, simian virus 40 (SV40) large tumor (T) antigen, and helicase B, derived from F plasmid, SV40, and mouse FM3A cell, respectively. The complex impeded the unwinding activities of all tested helicases in a specific orientation, with the same polarity observed in case of blockage of a replication fork, and, as a result, there was a block of SV40 DNA replication in both crude and purified enzyme systems in vitro. As the specificity in polarity of inhibition extends to heterologous systems, there may be common structure/mechanism features in helicases.

Highly conserved eight amino acid sequence in SH2 is important for recognition of phosphotyrosine site

Src homology region 2(SH2) has been demonstrated to recognize phosphotyrosine site. To clarify the precise mechanism of the recognition, we developed in vitro binding assay system using EGF receptor and SH2/SH3 region of phospholipase C(PLC) gamma 1. Phosphorylated EGF receptor bound to immobilized SH2/SH3 of PLC gamma 1 in Sepharose beads, while nonphosphorylated EGF receptor did not bind. In SH2 domain of PLC gamma 1, there are several highly conserved amino acid sequences that are common in a variety of SH2-containing proteins. Especially the eight amino acid sequence, G(S/T)FLVR(E/D)S is highly conserved in these proteins. We synthesized several peptides related to these sequences and examined the effect of peptides on the binding of EGF receptor to SH2 of PLC gamma 1. P1, GSFLVRES was the most effective inhibitor to suppress the binding. P2, GSFLVAES in which one amino acid, arginine of P1 is substituted by alanine is still effective. But a peptide, P3, SFLVRE in which two amino acids are deleted from P1 did not inhibit markedly. Moreover, P1 peptide immobilized in Sepharose beads also bound phosphorylated EGF receptor. These data suggest that highly conserved amino acid sequence GSFLVRES is the minimum essential unit to recognize tyrosine phosphorylated site.

[Serum deoxythymidine kinase activity in adult T-cell leukemia]

Serum deoxythymidine kinase activities (s-TK) of the patients with adult T-cell leukemia (ATL), carriers and healthy persons were measured, using a recently developed TK assay with 125I-iodo-deoxyuridine as a substrate. The mean s-TK values were 3.3 +/- 2.7 U/l (n = 21) in normal subjects (HTLV-1(-)), 4.7 +/- 5.0 U/l (n = 35) in carriers, 9.8 U/l (n = 3) in smoldering ATL and 26.7 U/l (n = 6) in chronic ATL. In the patients with acute ATL, the mean s-TK values before and after chemotherapy were 80.9 U/l (n = 2) and 11.6 U/l (n = 4), respectively. In the follow-up studies of the patients with acute ATL, the changes of s-TK levels revealed earlier than those of serum LDH levels. It is suggested that s-TK activity is more useful than LDH as a parameter of monitoring treatment in ATL.

[Optimal hypervolemic therapy for symptomatic vasospasm]

Thirty-five patients with symptomatic vasospasm (SV) following aneurysmal subarachnoid hemorrhage (SAH) were managed according to a method based on hemodynamic manipulation, monitored by Swan-Ganz catheter. Nine out of these had delayed surgery. For those who developed SV, the pulmonary wedge pressure (Pcwp) and/or central venous pressure (CVP) were immediately increased up to the point at which neurological deficit was reversed by rapid injection of fresh frozen plasma, albuminates, low molecular dextrose, and glycerol. On this regimen, patients were closely observed for any neurological change. Then the hemodynamic parameters were maintained as optimal values until they could be reduced below optimal values without reappearance of neurological deficit. In inoperable patients, special attention was given in making a decision about discontinuing the regimen. The results were compared with thirty-seven patients with SV who were treated with conventional hypervolemic therapy (CHT) by continuous administration of albuminates. In the treatment of CHT, optimal values could hardly be established, so the same hemodynamic parameters were applied in all the cases. From this study, in the majority of the cases optimal values were found as follows: Pcwp up to 10-15 mmHg, and CVP below 11 cmH2O. On the contrary, in 20% of patients, neurological deficit was reversed by increasing CVP to a point not above 7 cmH2O. Correlation between neurological reversal and systemic blood pressure was not statistically significant. After this regimen (OHT), 74% of patients showed immediate improvement after volume expansion, and, in 80%, outcome was good, while 20% died. The motor function at the time of discharge was more than 3 on the manual test in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

A newly identified DNA replication terminus site, TerE, on the Escherichia coli chromosome

To search for heretofore unidentified DNA replication termination (Ter) sites on the Escherichia coli chromosome, we screened the entire Kohara lambda bacteriophage library using as probes the four known 22-bp Ter sequences. We found a Ter site, which we named TerE, located at 23.2 min on the linkage map. TerE inhibits only counterclockwise DNA replication. Macroscopically, five Ter sites are located in a periodic arrangement on the genome.

Altered expression of gangliosides in erythrocytes of paroxysmal nocturnal hemoglobinuria

In paroxysmal nocturnal hemoglobinuria (PNH), impaired glycosyl-phosphatidylinositol (PI)-anchoring of membrane proteins such as decay-accelerating factor has been known to lead to increased susceptibility to complement. Moreover, abnormal expression of non-PI-anchoring glycoproteins such as C3b/C4b receptor (CR1) or glycophorin-alpha also has been shown in PNH. Therefore, we biochemically analyzed glycosphingolipids (GSL) as one of the membrane glycoconjugates of PNH erythrocytes. Erythrocytes of all seven PNH patients showed altered expression of sialosyl GSL (gangliosides) as compared with the control erythrocytes of healthy donors. Both a sialosylparagloboside (IV6NeuAc-nLc4Cer) among four major gangliosides and some minor gangliosides in normal erythrocytes variably disappeared in erythrocytes from the peripheral blood of PNH patients. As one of the possible mechanisms of altered expression of gangliosides in PNH erythrocytes, structural analysis suggested impaired sialylation of GSL. These results suggest not only the altered metabolism of gangliosides in PNH erythrocytes, but also a metabolic disorder of membrane glycoconjugates as a new feature of PNH.

Epidemiology of abomasal nematodes of dairy cattle in Hokkaido, northern Japan

The prevalence and intensity of infection with abomasal nematodiasis was studied in dairy cattle of Hokkaido, northern Japan, for successive two years. During the period of March in 1985 to September in 1987, a total number of 393 abomasa of Holstein-Friesian cows was examined for nematode parasites. Nematodes were detected from 75% of the cows. The prevalence of nematode species detected was Ostertagia ostertagi 250 (63.6%), Mecistocirrus digitatus 181 (46.1%), Trichostrongylus axei 85 (21.6%) and Haemonchus sp. 1 (0.3%). The prevalence and population composition of each growth stage varied seasonally in O. ostertagi and M. digitatus. The large percentage of arrested larvae, early L4 O. ostertagi and immature L5 M. digitatus, detected during the mid-winter and the increasing percentage of matured adult populations of both species in early spring revealed the occurrence of the autumn associated arrested development (hypobiosis) phenomenon in bovine abomasum nematodes of Japan.

Purification of a DNA replication terminus (ter) site-binding protein in Escherichia coli and identification of the structural gene

In Escherichia coli cells, there is a protein that specifically binds to DNA replication terminus (ter) sites on the host and plasmid genome and then blocks progress of the DNA replication fork. We reported that extract of the cells carrying the plasmid with the tau gene, which was identified to be an essential gene for the termination reaction at the ter site, contained about an 8-fold increase in ter-binding activity of the plasmid-free cells. With improvement of the promoter region of the tau gene on the plasmid by site-directed mutagenesis, the host cells produced the ter-binding protein (Ter protein) over 2,000-fold. Using these over-producing cells as the enzyme source, the Ter protein was purified to apparent homogeneity. Molecular mass 36,000, amino-terminal amino acid sequence (45 residues) and composition of the protein were in good agreement with those deduced from DNA sequence of the tau gene. Footprinting using the purified Ter protein revealed a specific binding to the ter sequences.

Monoclonal antibody to galactosylceramide: discrimination of structural difference in the ceramide moiety

A mouse monoclonal antibody (mAb) was developed against monohexaosylceramide. This mAb differentially reacted on thin-layer chromatograms with 3 types of galactosylceramide (GalCer) obtained from bovine brain. Structural analysis of the 3 glycolipids revealed that they consisted of the same galactose and sphingosine but of apparently different fatty acids. Among the GalCers, the mAb reacted with teh two GalCers which contained alpha-hydroxy fatty acids, but not with GalCer composed of nonhydroxy fatty acids. These findings suggest that not only that the mAb discriminated the fatty acid composition in the ceramide moiety of GalCer, but also that the ceramide structure defines the immunological epitope as it is known to do for the carbohydrate moiety of glycosphingolipid.

Escherichia coli replication termination protein impedes the action of helicases

Identification of the consensus sequence for termination of replication (ter) in Escherichia coli and the isolation of the ter-binding protein (TBP) allowed us to test their effects on replication forks initiated at the unique origin of the E. coli chromosome (oriC) in a purified enzyme system. Replication was severely impeded by ter in a unique orientation when purified TBP was supplied to bind it. The target for blockage within the replication complex can now be ascribed to the inability of dnaB helicase to separate the duplex strands when it encounters ter bound by TBP. Other helicases, such as rep and uvrD proteins, that translocate on DNA and displace strands in the direction opposite to that of dnaB protein are also blocked, but only when the TBP-bound ter is oriented in the other direction. From these results, we infer that the orientation of ter confers a particular polarity on the TBP seated on it, such that a helicase is blocked when it confronts TBP from one side, but can act, presumably by displacing TBP, when facing its other side. Thus, the intrinsic nature of the oriented TBP-ter complex is responsible for impeding the helicases, rather than any protein-protein interactions.

[Case report: hemiballism due to a putaminal cavernous hemangioma]

A rare case of reversible hemiballism due to putaminal pathological process in a 51-year-old woman is described. She was hospitalized for evaluation of hemiballism and muscle weakness on the left side. A cranial computed tomography scan demonstrated a high density lesion in the right putamen with enhancement on delayed scan. Angiographic examination revealed no apparent abnormalities. Magnetic resonance imaging with T1 weighted showed a isodense lesion in the right putamen, while T2 weighted image revealed a ring like low signal area around a high signal lesion. These findings were compatible with the diagnosis of cavernous hemangioma. In order to establish the final diagnosis, CT-guided stereotaxic biopsy was carried out. But histological specimen showed only gliosis and calcification. Immediately after the biopsy, a small hemorrhage took place in the right putamen extending to the head of caudate nucleus head. Following this episode, hemiballism ceased, however, it gradually returned along with absorption of hemorrhage. The speculated pathophysiology of this on-and-off hemiballism was as follows; it initially developed as the result of suppression of inhibitory fibers from the striatum to the pallidum by a minor hemorrhage of putaminal cavernous hemangioma, and ceased by declining the activities of the pallidum due to interruption of excitatory fibers from the thalamus and the cortex to the striatum.

[Low-dose dopamine treatment of patients in nonketotic hyperosmolar hyperglycemic coma]

In the acute neurosurgical setting, nonketotic hyperosmolar hyperglycemic coma (NHC) is thought to be caused by cerebral dehydration therapy and administration of steroids, glycerol, or mannitol. The mortality of this complication is reportedly very high, and is due to acute renal and/or cardiac failure. The authors evaluated the effect of low-dose dopamine (LDD; 1 to 5 micrograms/kg/min) administration in 10 patients with this syndrome. LDD was given to five patients. In these cases, hypovolemia was treated under central venous pressure monitoring with an iso-osmolar hyponatremic lactate solution given in a volume greater than the urine output. After the hypovolemia was corrected, the fluid was administered in a volume equal to the urine output until the serum osmolarity was normalized. In the five patients not given LDD, a large quantity of hypotonic solution was rapidly administered. In all patients treated with LDD, the urinary sodium increased and the urinary output stabilized. Consequently, the excess urea-nitrogen and serum sodium were quite easily washed out. The total net intake volume for the normalization of serum osmolarity was small and the duration of treatment was much shorter than that of patients not treated with LDD. The LDD regimen was not associated with complications, such as aggravation of cerebral edema, renal failure, or cardiac failure. On the other hand, three of the five patients not given LDD died of acute renal and/or cardiac failure without normalization of laboratory data. It is emphasized that this therapy, which results in beta-effect of catecholamine, sodium diuresis, and increased renal blood flow, is a practical means of managing acute neurosurgical cases complicated by NHC.

Evidence of a ter specific binding protein essential for the termination reaction of DNA replication in Escherichia coli

Activity binding specifically to the 22 bp of the DNA replication terminus (ter) sequence on plasmid R6K and the Escherichia coli genome was detected in the crude extract of E. coli cells. This activity was inactivated by heat or by protease but not by RNase treatments. Overproduction of the ter binding activity was observed when the extract was prepared from the cell carrying a plasmid with a chromosomal-derived 5.0 kb EcoRI fragment, on which one of the four terC sites, terC2, was also located. By mutagenesis of the 5.0 kb fragment on the plasmid with transposon Tn3 and subsequent replacement of the corresponding chromosomal region with the resulting mutant alleles, we isolated tau- mutants completely defective in ter binding activity. These mutants simultaneously lost the activity to block the progress of the DNA replication fork at any ter site, on the genome or the plasmid. It would thus appear that the ter binding protein plays an essential role in the termination reaction, at the ter sites.

[Synthesis and reactivity of anthracene-1-carbonyl azide as a fluorescent derivatization reagent for alcohols]

Anthracene-1-carbonyl azide was found to be a sensitive fluorescent derivatization reagent for primary and secondary alcohols for high-performance liquid chromatography. Reaction conditions were investigated for cholestanol. The reagent reacts with alcohols in benzene in the presence of 4-dimethylaminopyridine to give the corresponding fluorescent urethanes at 100 degrees C for 50 min. The detection limit for cholestanol was 250 fmol for an injection volume of 10 microliters. Tertiary alcohols and phenols do not produce fluorescent derivatives under these conditions.

[Peripheral superior cerebellar artery aneurysm. Case report]

The patient, a 37-year-old female, was hospitalized with a severe headache. Neurological examination on admission revealed no deficits except for neck stiffness and somnolence. Computed tomography showed a subarachnoid hemorrhage, which was especially prominent in the supracerebellar and quadrigeminal cisterns, but demonstrated no ventriculomegaly. Cerebral angiography on admission revealed no apparent abnormalities, but repeat angiography 8 days later disclosed a saccular aneurysm (2 X 3 mm) arising from the hemispheric branch of the left superior cerebellar artery (SCA). Three days after admission, the patient developed cerebellar dysarthria, which was assumed to be due to vasospasm. On the 24th day after admission, the aneurysm was successfully clipped through the infratentorial-supracerebellar approach. The postoperative course was uneventful and the patient was discharged with no neurological deficit. Nineteen other cases of peripheral SCA aneurysm have been reported in the literature. The presence of this type of aneurysm should be considered in patients who are fairly young and have focal neurological signs, such as third or fourth nerve palsy and/or cerebellar dysfunction. The prognosis for such patients is good, except in cases in which the neurological status is poor at the onset.

Characteristic mode of action of gangliosides in selective modulation of CD4 on human T lymphocytes

We have explored the possible mechanisms for selective modulation by gangliosides of CD4 on human T lymphocytes and subsequent re-expression of CD4. Indirect immunofluorescence staining with anti-CD4 antibodies revealed newly internalized CD4 in ganglioside-treated cells after membrane permeabilization with 0.1% saponin. Cycloheximide and other metabolic inhibitors did not alter the modulation but inhibited significantly the re-expression of CD4. These results suggest both selective modulation of CD4 by a process of endocytosis and re-expression of CD4 through de novo protein synthesis.

["AB-Triple V" therapy of relapsed or refractory acute myelogenous leukemia]

Sixteen adults with acute myelogenous leukemia (AML) in relapse or refractory to conventional therapy were treated with AB-Triple V therapy. This regimen consists of aclarubicin, behenoyl cytosine arabinoside, etoposide, vincristine, and vinblastine or vindesine. Patients who obtained complete remission (CR) were then given monthly three courses of AB-Triple V therapy, and further courses of AB-triple V therapy every three months. Eleven of the 16 patients entered CR, three were no response, and two died early after initial AB-Triple V therapy. Among 11 patients who achieved CR, 7 are alive and in CR during 1 to 13 months, one died of hepatic failure, and three patients died of infection in CR. Systemic arthralgia following the administration of vinblastine were frequently observed. These results indicate that this salvage therapy are useful relapsed or refractory AML. Therefore, the role of this combination chemotherapy as a part of the initial post-remission therapy needs to be evaluated.

Five cases of ectopic liver and a case of accessory lobe of the liver

Five cases of ectopic liver, two of retro-peritoneal cavity and three of gallbladder, and a case of accessory lobe of the liver, are reported. One of these cases with ectopic liver was accompanied by multiple cysts of the liver and kidney, and biliary microhamartoma, which was observed laparoscopically on the surface of the main liver and histologically proven in the ectopic liver.

Alteration of infection pattern of duck hepatitis B virus by immunomodulatory drugs

The relationship between host immune state and hepatic inflammation and infection pattern of the Duck hepatitis B virus (DHBV) was investigated by experimental transmission of DHBV into 98 Japanese 7-day-old ducklings that had been pretreated with immunoregulatory drugs including cyclophosphamide, OK 432, and a steroid hormone. Immunosuppressive treatment with cyclophosphamide revealed an extension of the viremic period associated with an absence of inflammatory changes in the liver. Although immunostimulating treatment with OK 432 showed a remarkable accumulation of inflammatory cells in the liver, the viremic period was not shortened. Treatment with a steroid used as a immunosuppressant did not suppress the hepatitis; moreover, it increased viral DNA replication and extended the viremic period. This phenomenon of viral replication seemed to be caused by the direct effects of the steroid. Alteration of DHBV infection by modifying the host immune state is quite similar to that of hepatitis B virus (HBV) in humans. In DHBV infection, the host immune state seemed to have a considerable role in determining the infection pattern and degree of hepatitis activity. DHBV may be a helpful model of HBV for studying host-viral interaction and the immunological mechanism of viral hepatitis.

A consensus sequence of three DNA replication terminus sites on the E. coli chromosome is highly homologous to the terR sites of the R6K plasmid

Using the "Ter assay" we developed, three separate replication terminus (terC1, terC2, and terC3) sites on the E. coli chromosome were identified. The locations are at 28.3, 35.6, and 33.9 min on the linkage map, respectively. The terC1 site can block the counter-clockwise replication fork only, while the terC2 and terC3 sites inhibit the clockwise fork traveling on the chromosome. DNA sequences of the terC sites required for termination of DNA replication are highly homologous to those of terminus (terR) sites of the R6K plasmid, and the 21 bp consensus DNA sequence of terC is 5'-(A or T) TTAGTTACAACAT (A or C) CT (A or T) (A or T) (A or T) T-3'. In addition, all Ter active pUC-terC plasmids had a low copy number and were unstable in the host cells.

[Autotransplantation of nipple-areolar complex in a modified radical mastectomy--indications and three-stage breast reconstruction]

Necessity of breast reconstruction after mastectomy has been increasing in recent years. For better reconstruction, we preserve a nipple-areolar complex (NAC) by transplanting it temporarily onto the lower abdominal wall and retransplant it to the restored breast mound in a subsequent operation. Indications for NAC preservation are as follows: (1) by palpation the tumor is found to be smaller than 3.0cm in diameter without apparent regional and distant metastasis, (2) neither abnormal nipple discharge nor nipple retraction is observed, (3) tumor is remote more than 3.0cm from the areolar margin, (4) no abnormal shadows are seen below the nipple and areola in the mammogram, (5) no microscopic extension of the cancerous cells is detected beneath the resected NAC. We have performed 18 transplantations using this procedure with good cosmetic results. There were no recurrent cases due to NAC preservation. It is concluded that this technique for preserving the NAC by autotransplantation is easy to perform and useful for breast reconstruction because of low risk of recurrence and better cosmetic results.

Two cis-acting elements responsible for posttranscriptional trans-regulation of gene expression of human T-cell leukemia virus type I

The pX sequence of human T-cell leukemia virus type I codes for two nuclear proteins, p40tax and p27rex, and a cytoplasmic protein, p21x-III.p40tax activates transcription from the long terminal repeat (LTR), whereas p27rex modulates posttranscriptional processing to accumulate gag and env mRNAs that retain intron sequences. In this paper, we identify two cis-acting sequence elements needed for regulation by p27rex: a 5' splice signal and a specific sequence in the 3' LTR. These two sequence elements are sufficient for regulation by p27rex; expression of a cellular gene (metallothionein I) became sensitive to rex regulation when the LTR was inserted at the 3' end of this gene. The requirement for these two elements suggests an unusual regulatory mechanism of RNA processing in the nucleus.

Core sequence of two separable terminus sites of the R6K plasmid that exhibit polar inhibition of replication is a 20 bp inverted repeat

The DNA replication terminus (terR) of the R6K plasmid located on a 216 bp Alul fragment (Alu216) can block progress of the DNA replication fork. We previously developed an electrophoresis assay that allows detection of terminus activity on any DNA fragment cloned in the pUC vector. For precise identification of terR, we tested Alu216, its subfragments, and synthetic oligonucleotides by this assay. We found terR to be composed of a pair of separable sites, terR1 and terR2, each of which can block the DNA replication fork traveling in a specific but not the opposite direction. Both terR sites were composed of 22 nucleotides containing the repeated 20 bp sequence 5'-TAGTTACAACAC(A or T) CAA(G or T) AGA-3', located 73 bp apart in the inverted position of Alu216. A DNA homology search suggested that the R6K plasmid and the E. coli chromosome share a common termination system.

Post-transcriptional regulator (rex) of HTLV-1 initiates expression of viral structural proteins but suppresses expression of regulatory proteins

Gene expression of human T-cell leukemia virus type 1 (HTLV-1) is regulated by two trans-acting factors encoded by the pX region, p40tax and p27tax.p40tax is a transcriptional activator and p27rex is a post-transcriptional regulator. Using full-length viral DNA, we studied the regulatory effects of rex on HTLV-1 gene expression. p27rex is required for expression of both gag and env proteins, increasing the level of their mRNAs. The effect was dependent on the dose of p27rex expression plasmid. In parallel, increased doses of p27rex suppressed the expression of fully spliced pX mRNA, which encodes the regulatory proteins. These two effects of p27rex operated at the post-transcriptional level and were independent of transcriptional regulation. Lowering the level of pX mRNA down-regulates transcription of the proviral genome. These observations demonstrate that rex is a positive post-transcriptional regulator for gag, pol and env protein expression, and acts at the same time as an indirect negative regulator of viral transcription.

An experimental study on viability of the devascularized trachea

This experiment was designed to evaluate the effect of varying extents of devascularization to the viability of the trachea, and the influence of preservation of the right bronchial artery on the ischemia of the widely devascularized trachea. In experiment 1, the canine trachea was devascularized in a stepwise manner, and the regional blood flow was measured in each situation. This experiment revealed that the regional blood flow decreased to one-third of the non-treated trachea when the bilateral bronchial arteries were transected, and to nil when the cervical and mediastinal trachea was devascularized. In experiment 2, in which dogs were divided into 2 groups depending on preservation of the right bronchial artery, the trachea was stepwisely devascularized and the regional blood flow measured. This experiment indicated that the regional blood flow in the trachea when the right bronchial artery was preserved did not so remarkably diminish, though the cervical and mediastinal trachea was devascularized. In experiment 3, dogs were divided into 3 groups according to the extent of devascularization of the trachea and to the presence or absence of the preserved right bronchial artery, and were followed for 2 months postoperatively. This experiment demonstrated that the preservation of the right bronchial artery prevented tracheal necrosis caused by devascularization of the cervical and mediastinal trachea. We concluded that the regional tracheal blood flow markedly decreased and that tracheal necrosis occurred following devascularization of the cervical and mediastinal trachea when the bilateral arteries were transected. The preservation of the right bronchial artery however, prevented a decrease in the regional blood flow and necrosis of the widely devascularized trachea.

Replication intermediate of a hybrid plasmid carrying the replication terminus (ter) site of R 6K as revealed by agarose gel electrophoresis

A 4.32 kb DNA fragment, on which the DNA replication terminus (terR) site of plasmid R 6K was located, was inserted into the unique EcoRI site of plasmid pUC9. To detect replication intermediate molecules with a replication fork halted at the terR site, a cell DNA extract was digested with EcoRI, electrophoresed through an agarose gel and stained with ethidium bromide. In addition to two major bands, one derived from vector DNA and the other from the ter insert fragment, two extra minor bands were detected. Following DNA-DNA hybridization and electron microscopic observation we concluded that the two minor bands corresponded to the two Y-shaped molecules, produced from the theta-shaped intermediate molecules by EcoRI digestion.

The latissimus dorsi muscle flap is useful for the repair of tracheal defects--an experimental study

An experiment was designed to evaluate the limitations of the muscle flap method in treating various locations and sizes of tracheal defects. Five groups of dogs with several types of tracheal defects were prepared. Each defect was covered by the latissimus dorsi muscle flap. Defects of the tracheal membrane (posterior one-third of the tracheal wall) were successfully repaired by the muscle flap without stenosis, even if they extended to 10 rings in length or were situated at the carina. Defects in the posterior one-half of the trachea, up to 5 rings long, were repaired, with minimal stenosis. Defects of the posterior two-thirds, or anterior one-third of the trachea, resulted in marked stenosis following muscle flap repair. Tracheal movement as seen in the saver sheath type of tracheomalasia was observed when anterior support of the trachea was lost. On the other hand, the movement seen in the crescent type of tracheomalasia was observed when posterior support of the trachea was lost. We concluded that a defect of less than the posterior one-half of the trachea can be repaired by muscle flap, without inducing respiratory insufficiency. Therefore, muscle flap coverage for tracheal defects should be a useful technique in the combined resection of the tracheobronchial tree in cases of esophageal cancer.

Cloning and structural analysis of the calf prochymosin gene

Calf prochymosin (cPC) gene was cloned from calf abomasum DNA by using a cloned cPC cDNA as a probe. The cPC gene spans approx. 10.5 kb and consists of 9 exons and 8 introns. The positions of exon-intron junctions coincide completely with those in the human pepsinogen gene. Analysis of 5'-flanking region sequence and S1 nuclease mapping revealed that the transcriptional start point was located 25 bp upstream from the start codon and that the putative transcriptional promoter sequences (TATA box and CCAAT box) were located in -30 and -90 regions, respectively. Some distinctive sequences possibly functioning as regulatory signals for gene expression are present at the 5'-flanking region.

[Combined resection of the thoracic aorta associated with subtotal esophagectomy for carcinoma of the esophagus]

With recent advances in surgical techniques and post-operative care, surgical treatment of esophageal cancer has been safely performed. Nevertheless, prognoses of such cases in which the cancer is invading the ajacent aorta and when only an incomplete resection was performed are very poor. The following case in which annular resection of the thoracic aorta combined with subtotal esophagectomy was performed and an aorto-aortic bypass graft was replaced was reported. A 70 year old man came to our hospital, complaining of difficulty in swallowing. The upper GI series showed a 8 cm long filling defect in the middle esophagus. Computed tomography suggested that the tumor was directly invading the aorta. The patient underwent two staged procedure operations. During the first operation, the left chest was opened, and a side-to-end bypass graft was replaced to detour around the tumor bearing aorta with 20 mm phi Dacron Double Velour graft. The aorta was then transected. The second operation was performed through the right thoracotomy. During the operation, the thoracic esophagus and the tumor bearing aorta were resected en bloc. The patient died of hepatic failure and right pyothorax 4 months after the first operation.

Expression of cloned calf prochymosin cDNA under control of the tryptophan promoter

To increase yields of calf prochymosin (PC) produced in Escherichia coli, PC cDNA was cloned in a plasmid vector under control of the trp promoter. The hybrid plasmid pCR501 constructed for this purpose contains cDNA coding for PC (from the 5th Arg to the C-terminal Ile) fused to the N-terminal fragment of the trpE gene preceded by the trp promoter and attenuator region. E. coli C600 harboring this plasmid produces approx. 300 000 molecules of PC per cell. This is about a tenfold increase above the amount obtained using lacUV5 promoter [Nishimori et al., Gene 19 (1982) 337-344]. A similar plasmid, pCR601, which contains the same coding sequence fused to the trp promoter and N-terminal fragment of the trpL gene, directs the production of PC at the same rate as pCR501. In pCR601 the trp attenuator is deleted. Another plasmid, pCR701, in which construction of a sequence coding for fMet-PC cDNA that was aided by chemical synthesis, was placed under direct control of the trp promoter, produced PC at a much lower rate. Extracts prepared from all these bacterial transformants in the presence of urea showed distinct milk-clotting activity after renaturation and processing.