Dexmedetomidine reduces seizure threshold during enflurane anaesthesia in cats

Dexmedetomidine is an alpha 2 agonist and has been reported to have proconvulsant actions. To investigate the interaction of dexmedetomidine with convulsant anaesthetics, we studied effects on seizure threshold in cats during enflurane anaesthesia. Cats were prepared with chronic implantation of electrodes for recording of the cortical electroencephalogram (EEG) and midbrain reticular formation multi-unit activity (R-MUA). Seizure threshold, the reciprocal of the number of electrical stimuli required to induce generalized EEG seizure activity x 1000 (seizure induction index (SII)), was assessed. The effects of dexmedetomidine 1, 10 and 100 micrograms kg-1 i.v. and yohimbine 500 micrograms kg-1, an alpha 2 antagonist, on SII during 3.5% enflurane anaesthesia were investigated. Dexmedetomidine significantly increased SII at 10 and 100 micrograms kg-1, and this effect was reversed by yohimbine. We found that high-dose dexmedetomidine reduced seizure threshold during enflurane anaesthesia.

Xenon has greater inhibitory effects on spinal dorsal horn neurons than nitrous oxide in spinal cord transected cats

Xenon (Xe) suppresses wide dynamic range neurons in cat spinal cord to a similar extent as nitrous oxide (N2O). The antinociceptive action of N2O involves the descending inhibitory system. To clarify whether the descending inhibitory system is also involved in the antinociceptive action of Xe, we compared the effects of Xe on the spinal cord dorsal horn neurons with those of N2O in spinal cord-transected cats anesthetized with alpha-chloralose and urethane. We investigated the change of wide dynamic range neuron responses to touch and pinch by both anesthetics. Seventy percent Xe significantly suppressed both touch- and pinch-evoked responses in all 12 neurons. In contrast, 70% N2O did not show significant suppression in touch- and pinch-evoked responses. These results suggest that the antinociceptive action of Xe might not be mediated by the descending inhibitory system, but instead may be produced by the direct effect on spinal dorsal horn neurons.

IMPLICATIONS

Xenon (Xe) is an inert gas with anesthetic properties. We examined the antinociceptive effects of Xe and nitrous oxide (N2O) in spinal cord-transected cats. Our studies indicate that Xe has a direct antinociceptive action on the spinal cord that is greater than that of N2O.

Effect of xenon on central nervous system electrical activity during sevoflurane anaesthesia in cats: comparison with nitrous oxide

We have compared the effects of xenon and nitrous oxide on central nervous system (CNS) electrical activity during sevoflurane anaesthesia in cats by recording the electroencephalogram (EEG), multi-unit activity of the midbrain reticular formation (R-MUA) and somatosensory evoked potentials (SEP). Basal anaesthesia with 2% and 5% sevoflurane was used. With 2% sevoflurane, 70% xenon initially produced rhythmic slow waves which were followed by bursts of high-amplitude sharp waves interrupted by low amplitude slow waves on the EEG. Xenon induced an initial increase, followed by a decrease in R-MUA. Nitrous oxide 70% decreased the amplitude of the EEG activity which was associated with an increase in R-MUA. Xenon suppressed the amplitude of both the initial positive and negative deflections of the SEP to a greater extent than nitrous oxide. With 5% sevoflurane anaesthesia, both anaesthetics increased the frequency of spikes on the EEG and facilitated R-MUA. These findings indicate that xenon has a stimulatory action on CNS background activity and a suppressive action on CNS reactive capability which is more potent than that of nitrous oxide.

Primary familial polycythaemia associated with a novel point mutation in the erythropoietin receptor

Primary familial and congenital polycythaemia (PFCP) is a rare disease characterized by congenital erythrocytosis inherited in an autosomal dominant fashion. Recently, mutations in the erythropoietin receptor (EpoR) have been identified in PFCP families. We describe a Japanese family with an autosomal dominant inheritance of PFCP. An in vitro colony assay demonstrated hypersensitivity of erythroid progenitors to erythropoietin (Epo) in affected family members. Sequence analysis of RT-PCR products amplified from the C-terminal region of EpoR transcripts in affected family members revealed that they were all heterozygous for C and T bases at position 5986, which suggested a genetic mutation (C to T) on one allele of EpoR. This mutation gave rise to a translation termination codon TAG at amino acid 435. Thus, the resulting EpoR is a truncated protein product lacking all 74 amino acids downstream of the mutation. To date, all genetic mutations affecting a family with PFCP, including this one, have been located in the cytoplasmic negative regulatory region of the EpoR. All mutations gave rise to truncated Epo receptors between Tyrosine 427 and Tyrosine 455. The phosphotyrosines in this region of EpoR have been demonstrated to be binding sites for SHP-1 phosphatase. Therefore PFCP is presumably brought about as a result of genetic mutations which cause the loss of the SHP-1 binding site in the cytoplasmic region of EpoR.

The effect of xenon on spinal dorsal horn neurons: a comparison with nitrous oxide

We compared the effects of xenon (Xe) on the spinal cord dorsal horn neurons with those of nitrous oxide (N2O) in cats anesthetized with chrolarose and urethane. We assessed the potency of both anesthetics by the inhibition of wide dynamic range neuron responses evoked by cutaneous noxious (pinch) stimulation to a hindpaw. During 70% Xe inhalation, the responses of 7 of 11 neurons to pinch stimulation were suppressed. N2O, 70%, suppressed it in 8 of 11 neurons. The potency of Xe and N2O was compared in six neurons that were suppressed by both anesthetics. After 20 min of Xe inhalation, the response to pinch was suppressed to 49.5% +/- 8.2% (mean +/- SE), while N2O, 70% in oxygen, suppressed it to 45.9% +/- 7.9%. The difference between N2O and Xe was not significant. We conclude that Xe and N2O suppress the spinal cord dorsal horn neurons to a similar degree.

[Myelogenous leukemia in children. ANLL9205 study by Children's Cancer and Leukemia Study Group (CCLSG)]

Treatment results were evaluated in 45 children with acute myeloblastic leukemia (AML) treated on the ANLL-9205 protocol of the Children's Cancer Leukemia Study Group (CCLSG, Japan). In this protocol, terarubicin (THP-ADR), vincristine and continuous infusion of cytosine arabinoside (Ara C) were applied for remission induction therapy (AVC), and VP16+ high dose Ara C were used sequentially for 32 or 48 weeks. Eleven patients received stem cell transplantation. Thirty-eight out of the 43 eligible patients (88.4%) achieved complete remission, and the overall 3-year event-free survival (EFS) was 55.6% (S.E.,10%). This favorable response was attributed mainly to the high induction rate of patients with the M5, M7 FAB subtypes and higher WBC counts (> or = 10 x 10(9)/L). There was no difference in the 3-year EFS of these patients who discontinued treatment between 32 weeks and 48 weeks. Serious toxicities were not observed in this study. These findings suggest that the ANLL-9205 protocol is an effective and safe treatment regimen for childhood AML. When comparing the treatment period of 32 or 48 weeks, the difference was not statistically significant.

Evaluation of patients with advanced neuroblastoma surviving more than 5 years after initiation of an intensive Japanese protocol: a report from the Study Group of Japan for Treatment of Advanced Neuroblastoma

In January 1985, a single protocol consisting of cyclophosphamide, vincristine, tetrahydropyranyl adriamycin, and cis-platinum for the treatment of advanced neuroblastoma was begun nationwide in Japan and was found to improve clinical results significantly in terms of 2- or 3-year survival rate. Between January 1985 and December 1988, 113 eligible patients (7 infants younger than 12 months of age with stage IVA disease and 106 patients aged 12 months or older with stage III or IV disease) were enrolled and followed up for 5 years or more after initiation of treatment, as of March 1994. In this study, the usefulness of the protocol for the treatment of advanced neuroblastoma was evaluated with survival rates in relation to age, tumor site, stage, and N-myc amplification for patients surviving more than 5 years after initiation of the protocol. Fifty of the 113 patients were alive 5 years or more after initiation of the treatment, 39 without any episodes of disease recurrence. Fourteen (70%) of 20 patients with stage III, 6 (50%) of 12 with stage IVB, and 24 (30%) of 81 with stage IVA disease were alive and disease-free 5 years after initiation of the protocol. Twenty (56%) of 36 patients without N-myc amplification were alive at 5 years after initiation of the protocol. Only one patient who was alive without evidence of the disease at 5 years had recurrence afterward.

Nitrous oxide depresses somatocardiac sympathetic A- and C-reflexes in anesthetized rats

Effect of nitrous oxide (N2O) on the somatosympathetic A- and C-reflexes was investigated using artificially ventilated rats anesthetized with alpha-chloralose and urethane. Somatocardiac sympathetic A- and C-reflexes were elicited in the inferior cardiac nerve by electrical stimulation of A and C afferent fibers of the tibial nerve, respectively. Both reflexes were depressed by inhalation of N2O for 20 min. The depression was greater in the C-reflex than in the A-reflex. The depressive effects of N2O on both reflexes were unchanged after pretreatment with intravenous naloxone (0.2 or 2.0 mg/kg) or by prolongation of the inhalation of N2O for 2 h. These results suggest that the opioid receptor is not involved and that acute tolerance is not developed in the depressive action of N2O on the somatosympathetic A- and C-reflexes.

Growth inhibition of human glioma cells by superinduced human interferon-beta

Superinduction of human interferon-beta (HuIFN-beta) from human glioma cells has greater cytotoxicity than purified HuIFN-beta derived from fibroblasts. However, superinduction requires several reagents like polyI:polyC, cycloheximide, and actinomycin D, which may contaminate the conditioned medium and obscure the effect of superinduced HuIFN-beta. The present study used minimum doses of polyI:polyC and cycloheximide without actinomycin D to superinduce HuIFN-beta. The superinduced HuIFN-beta was purified by passing the medium through molecular sieve column chromatography. Fractionation of the eluate provided semipurified superinduced HuIFN-beta which demonstrated a growth inhibitory effect against both the U251-MG autologous human glioma cell line and the SK-MG-1 homologous glioma cell line. This effect was neutralized by addition of anti-HuIFN-beta monoclonal antibody (YSB-1). In a separate experiment, combinations of superinduction reagents were found not to have growth inhibitory effects because all inhibition in superinduced medium was completely neutralized by YSB-1. Superinduced HuIFN-beta has a pure growth inhibitory effect on both autologous and homologous glioma cells, so may affect autocrine secretion of cytokines.

Successful treatment of retinoic acid syndrome with high-dose dexamethasone pulse therapy in a child with acute promyelocytic leukemia treated with ATRA

A 5 year old female developed femoral pain, fever, and hemorrhagic tendency. She was diagnosed as having acute promyelocytic leukemia (APL). Approximately 2 weeks after the administration of all-trans retinoic acid (ATRA), she developed a high fever, edema, and respiratory distress which met the criteria for retinoic acid syndrome. At first, we tried to treat the patient with oral corticosteroid, however, this approach was unsuccessful. Considering the worsening of her condition, we then chose to administer a large dose of intravenous dexamethasone therapy for 3 days. Immediately after this therapy, she became afebrile, respiratory distress and edema disappeared, and there was a general improvement of the symptoms. All-trans retinoic acid at the reduced dose of 25 mg/m2, was continued for an additional 6 weeks and then discontinued. Since the cessation of dexamethasone and ATRA, there has been no relapse of APL in this patient. Although based on only one case, we recommend the intravenous high-dose dexamethasone pulse therapy (13 mg/m2 per day, for 3 days) for treating retinoic acid syndrome which develops in pediatric APL patients treated with ATRA.

Pharmacokinetics and biologic activities of human native and asialointerferon-beta s

Glycoproteins are metabolized through an asialoglycoprotein metabolic pathway in vivo. They are desialylated and taken up by the liver via an asialoglycoprotein receptor. Fibroblast-derived natural human interferon-beta is a glycoprotein having a single asparagine-linked sugar chain. Although natural human interferon-beta may also be metabolized through this pathway, there is very little information about the biologic features of human asialointerferon-beta. We evaluated the pharmacokinetics and biologic activities of human native and asialointerferon-beta s. After intravenous administration to rabbits, human asialointerferon-beta was cleared from the blood circulation faster than the human native interferon-beta. More asialoprotein was distributed to the liver than the native type, but it induced less 2'5'-oligoadenylate synthetase. The human asialointerferon-beta had less activity than the human native interferon-beta on cell growth inhibition and 2'5'-oligoadenylate synthetase induction in Hep-G2 and HuH6 human hepatoblastoma cells. Southern blotting using a hepatitis B virus-transfected HuH6 cell line, HB611, revealed that the inhibition of hepatitis B virus DNA replication by the asialoprotein was weaker than that by the native protein. The results showed that the different effects exerted by the human native and asialointerferon-beta s may be a result of recognition of the sugar chains by rabbit hepatocytes or by human hepatoblastoma cells. The results also suggested that the terminal sialic acid of the sugar chains in natural human interferon-beta significantly affects its pharmacokinetics and biologic activities.

Purification and N-terminal sequence of a novel interferon-induced 100 kD protein secreted by mouse Ehrlich ascites tumor cells

Mouse Ehrlich ascites tumor cells secrete a 100 kD protein when they are stimulated by murine interferon-beta (2000 IU/ml). This 100 kD protein was purified from conditioned medium by chromatography on phenyl-Sepharose CL-4B, phosphocellulose, DEAE-Sephacel, and Vydac C4 columns and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A single species of 100 kD protein was isolated, and its N-terminal sequence analysis suggested that mouse Ehrlich ascites tumor cell-derived interferon-induced 100 kD protein is a novel protein.

Improved treatment results of non-Hodgkin's lymphoma in children: a report from the Children's Cancer and Leukemia Study Group of Japan

From 1985 to 1989, 69 patients with non-Hodgkin's lymphoma (NHL) were treated by members of the Children's Cancer and Leukemia Study Group of Japan with a protocol consisting of vincristine, prednisolone, cyclophosphamide, doxorubicin, high-dose methotrexate (HD-MTX), mercaptopurine and cytarabine; central nervous system (CNS) prophylaxis with intrathecal MTX and hydrocortisone (NHL855). The 4-year event-free survival (EFS) was 78% (S.E., 10%) for patients with localized disease (n = 18) and 38% (S.E., 7%) for those with advanced disease (n = 51). Among the patients with advanced disease, those with non-lymphoblastic lymphoma tended to have a better 4-year EFS than those with lymphoblastic lymphoma (52% vs. 25%). Based on these findings, we initiated a new protocol NHL890 in which patients were assigned to two different chemotherapies according to the histology. Non-lymphoblastic subtype was treated almost identically to NHL855 while asparaginase and VP-16 were newly added in the consolidation-maintenance phase in advanced-stage lymphoblastic lymphoma. Sixty-seven patients with advanced disease were assessable. The overall 4-year EFS for advanced disease improved to 69% (S.E., 6%). A significant improvement was gained in the lymphoblastic lymphoma with a 4-year EFS of 56% (S.E., 11%) as compared with 25% (S.E., 9%) in the preceding study (P < 0.05). These findings suggest the importance of histology in the treatment of advanced-stage non-Hodgkin's lymphoma in childhood.

Carbohydrate-dependent biological activities of glycosylated human interferon-beta on human hepatoblastoma cells in vitro

To evaluate the relationship between the sugar chain structure and biological activity, fibroblast-derived glycosylated human interferon-beta, Chinese hamster ovary cell-derived glycosylated recombinant human interferon-beta and Escherichia coli-derived unglycosylated recombinant human interferon-beta were evaluated using human hepatoblastoma cells in vitro. Native fibroblast interferon-beta expressed more cell-growth inhibitory action, 2'5'-oligoadenylate synthetase induction, and the inhibition of hepatitis B virus DNA replication than its asialoform and two recombinant interferon-betas. These results showed that the sugar chain structure of human interferon-beta affects its biological activity on human hepatoblastoma cells.

Assessment of testicular biopsy after cessation of maintenance chemotherapy in childhood acute lymphoblastic leukemia: a report from the Children's Cancer and Leukemia Study Group

Among 484 male patients with acute lymphoblastic leukemia (ALL) registered into the protocols CCLSG 811, 841 and 874, from 1981 through 1990, 246 patients completed their protocols and were in continuous complete remission (CCR) for more than 3 years. One hundred and seven patients received bilateral testicular biopsies at the time of cessation of maintenance chemotherapy. Eight patients (7.5%) were found to have occult testicular leukemia (TL). Three of them did not receive any additional therapy and all suffered subsequent relapses; one bone marrow relapse and two testicular relapses. The other 3 patients received testicular radiation combined with an additional 2 years of chemotherapy, resulting in CCR for more than 6 years 10 months, 7 years 6 months, and 8 years 6 months. One with chemotherapy alone and another with radiation alone showed subsequent relapse. Overt TL after negative initial biopsy was developed in 3 (3.0%) of the 99 patients. All of them received testicular radiation with chemotherapy, resulting again in CCR for more than 1 year 0 months and 5 years 3 months; one patient showed relapse in testes and bone marrow after 3 years 8 months of CCR. These studies suggested that occult TL has an adverse prognostic significance unless retrieval chemotherapy is given and that performance of testicular biopsy at completion of maintenance chemotherapy is not contributory to prolongation of disease-free survival for males with ALL because the treatment employing testicular radiation plus retrieval chemotherapy for both occult TL and isolated overt TL after off-therapy is similarly very effective.

What is the benefit of aggressive chemotherapy for advanced neuroblastoma with N-myc amplification? A report from the Japanese Study Group for the Treatment of Advanced Neuroblastoma

In 1985, a nationwide single protocol (cyclophosphamide, vincristine, tetrahydropyranyl Adriamycin, and cisplatin) for the treatment of advanced neuroblastoma was begun in Japan and was found to significantly increase the 3-year survival rate--to 70% for stage III, and to 45% for stage IV. In this study, the authors investigated the efficacy of this protocol for advanced neuroblastoma with or without N-myc amplification. In 159 of the 233 patients with advanced neuroblastoma treated with this protocol (between January 1985 and March 1993), genomic amplification of N-myc was determined. These 159 patients were divided into two groups according to the number of N-myc copies, ie, those with fewer than 10 copies (105 patients) and those with 10 or more copies (54 patients). The survival curves for the two groups were significantly different. The 5-year survival rate for patients with 10 or more copies was 43.9%; this is surprisingly high in comparison to results of previous studies in which no survivors were expected in cases of advanced neuroblastoma with highly amplified N-myc. Persistent bone marrow suppression was common, but there were no deaths attributable to drug side effects. Five patients with fewer than copies of N-myc amplification died more than 3 years after initial treatment. Three of the five had tumors with an unfavorable Shimada classification, and two had diploid nuclear DNA content. The authors conclude that the protocol resulted in dramatic improvement in the patients with advanced neuroblastoma, even with high N-myc amplification.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical characteristics and treatment results of acute promyelocytic leukemia in children (Children's Cancer and Leukemia Study Group)]

The clinical characteristics and treatment outcome in 40 children with acute promyelocytic leukemia (APL) treated at institutions participating in the Children's Cancer and Leukemia Study Group (CCLSG) were studied retrospectively. The median age at diagnosis was 8 years old. Bleeding diathesis was the predominant presenting symptom (90%), associated with laboratory findings of disseminated intravascular coagulation. Hepatomegaly, splenomegaly and lymphadenopathy were observed in 35%, 10%, and 15% of the cases, respectively. The median WBC count was 4.25 x 10(9)/l. Anemia (hemoglobin < 8 g/dl) and thrombocytopenia (< 30 x 10(9)/l) were present in more than half of the patients. Cytogenetic studies demonstrated the characteristic 15; 17 translocation in about 90% of the patients analyzed. Induction therapy consisted of cytosine arabinoside and an anthracycline, with or without other agents. Twenty-nine patients (73%) achieved complete remission (CR) while early fatal hemorrhage was the predominant cause of induction failure. The survival rates continued to decrease (28% at 3 years, 24% at 5 years, and 7.9% at 10 years) due to late marrow relapses. Anthracycline cardiotoxicity was fatal in three patients in remission. These clinical features of childhood APL should be taken into account in the development of new protocols.

Structural, functional and evolutionary implications of the three-dimensional crystal structure of murine interferon-beta

The crystal structure of recombinant murine interferon-beta as elucidated by Senda et al. (Proc. Jap. Acad. 66B: 77-80 (1990); EMBO J. 11: 3193-3201 (1992)) appears to represent the basic structural framework of all Type I interferons including interferons-beta and all subtypes of interferons-alpha of various mammalian origin. Now the huge accumulated data on the structure-activity relationship of Type I interferons using various chemical and genetic techniques can be systematically evaluated in terms of the three-dimensional structure. Structural comparison with other cytokines, for which three-dimensional structures have been established, including interferon-gamma and considerations on the evolution of cytokines and cytokine receptors are also given.

[Analysis of cytoplasmic antigens in acute leukemia by flow cytometry]

The expression of cytoplasmic antigens in 77 cases of acute leukemia were analyzed by flow cytometry using the following monoclonal antibodies: CD3, CD22, anti-myeloperoxidase (MPO-7) and anti-mu-heavy chain. CD22 antigen was detected in the cytoplasm of all non-T-ALL patients excluding one not-tested patient. In two patients with unclassified ALL, surface CD22 antigen was not expressed but cytoplasmic CD22 antigen was strongly expressed. Three out of 9 patients with common ALL were cytoplasmic mu-heavy chain-positive, so these patients were diagnosed as Pre-B ALL. In four out of 8 patients with T-ALL, CD3 antigen was not expressed on the cell surface membrane. However all of T-ALL patients excluding one non-tested patient were cytoplasmic CD3-positive. The cytoplasmic expression of myeloperoxidase antigen was detected in twenty out of 21 patients with acute non-lymphoblastic leukemia (ANLL). One megakaryocytic leukemia patient was MPO-negative. In two ANLL patients, the percentage of MPO for conventional cytochemical staining was undetectable or low, but MPO antigens were positive (77% and 70%) for flow cytometric analysis. All of 46 non-T ALL patients were cytoplasmic MPO-negative, however 4 out of 10 T-ALL patients were cytoplasmic MPO-positive. The study proved that the analysis of cytoplasmic CD3, CD22, mu-chain and MPO antigens were very useful to define the cell lineage of leukemia and to classify ALL and ANLL. It is necessary to study further whether the expression of MPO in the cytoplasm of T-ALL was non-specific reaction or whether MPO precursors are expressed in the cytoplasm of T-ALL.

[Transient subacute encephalopathy induced by high-dose methotrexate treatment in children with acute lymphoblastic leukemia and malignant lymphoma]

Transient subacute encephalopathy was detected in 4 of 83 patients undergoing treatment with high-dose methotrexate (HD-MTX) and citrovorum factor rescue for childhood acute lymphoblastic leukemia and malignant lymphoma from 1984 to 1991. Subacute encephalopathy occurred in relatively older patients and early in the course of treatment with HD-MTX. The average interval between the HD-MTX course and the onset of the neurologic disturbance was 6.5 days. All 4 patients treated had no neurological sequelae. Laboratory evaluations disclosed nontoxic plasma MTX levels at onset of symptom and not detected in liquor. CT in 4 patients disclosed no abnormality, but MR images revealed abnormal signal intensity patterns of cerebral white matter in 2 cases. In one case the abnormal MR finding resolved after 3 months. The pathogenesis of this neurologic symptom remains unknown, but further HD-MTX treatment may be acceptable in follow-up of MR image, because the prognosis of subacute encephalopathy seems favorable.

Retrospective analysis of late intensification therapy with high-dose methotrexate for standard-risk acute lymphoblastic leukemia in childhood (CCLSG-S811 study). The Children's Cancer and Leukemia Study Group

Using the CCLSG-S811 protocol for children with standard-risk acute lymphoblastic leukemia (ALL), late intensification therapy (LIT) with high-dose methotrexate (HD-MTX) was conducted without randomization. Of 118 eligible patients, 114 attained complete remission and 82 maintained continuous complete remission (CCR) for at least 3 years, completing the entire S811 regimen. Among the latter, 74 patients received LIT with HD-MTX between 2-3 years after CCR onset. MTX (2,000 mg/m2 per dose per week) was administered by 24 h infusion and three doses were given every 12 weeks. Leucovorin rescue (15 mg/m2 i.v.) every 6 h was initiated 12 h after the end of MTX infusion for seven doses. As regular maintenance chemotherapy, intermittent (Regimen A) or continuous (Regimen B) MTX plus 6-mercaptopurine (6MP) combined with pulses of prednisolone and vincristine was administered (Koizumi S, Fujimoto T, Takeda T, et al. Cancer 1988; 61: 1292-1300). Retrospective analysis revealed that patients on Regimen A who started LIT earlier (within 2 years of CCR onset (n = 23)) showed a higher rate of event-free survival (EFS) at 8 years (95.5% +/- 4.4%, mean +/- S.E.) than patients who started LIT later (2.5 years after CCR onset (n = 18, 66.2% +/- 11.3%, p less than 0.01)). In addition, the superiority of four or five courses of the LIT (n = 39) as compared to 2 or 3 courses (n = 35) was noted for both regimens. The data suggest that early and aggressive LIT with HD-MTX may improve the long-term survival of childhood ALL patients.

[Evaluation of myocarditis using T1-201 myocardial scintigraphy with bull's eye functional map]

In order to evaluate myocardial damage in a patient with myocarditis, rest thallium-201 myocardial single photon emission computed tomography (SPECT) was performed in 15 patients with myocarditis. For qualitative and semiquantitative analysis, Bull's eye functional maps were made up with SPECT images. In the functional map, the abnormal area, where T1 uptake is less than mean-2SD of the T1 uptake of normal subjects, is generally distributed in the myocarditis group. But focal and sequential abnormal areas were recognized more often in the clinically severe cases. Abnormal area tended to be observed commonly at the antero-septal wall, but it was uncommon at the lateral wall. Extent score, i.e. degree of extension of abnormal area, and severity score, i.e. degree of abnormality, were in good negative correlation with left ventricular ejection fraction (r = 0.6, r = 0.7). Furthermore, existence of abnormal area was in good correlation with the left ventricular regional wall motion. Abnormal area existed 100% in the akinetic region, 71% in the region of severe hypokinesis, and 27% in the region of hypokinesis. Abnormal area occupied 30% of the normokinetic region in the myocarditis group, which was a higher rate than in the normal control group (p less than 0.05). It was suggested that latent myocardial damage existed in the normokinetic myocardium with myocarditis. Thus, rest T1-201 SPECT with Bull's eye map is useful for clinical diagnosis in patients with myocarditis.

Target cell of leukemic transformation in acute megakaryoblastic leukemia

Acute megakaryoblastic leukemia (AMkL) is a newly defined acute leukemia in which the differentiation of proliferating blasts is arrested at the megakaryocytic precursor stage. In order to clarify whether a target cell of leukemic transformation in AMkL is a cell committed to megakaryocytic lineage, or a multipotential stem cell, we examined AMkL patients with regard to: a) the presence of myelodyplastic features in residual erythroid and granulocytic cells, b) coexistence of myeloperoxidase (MPO)-positive blasts with megakaryoblasts, and c) the presence of the same chromosomal abnormality in erythroid and granuloid colony-forming cells as seen in megakaryoblasts. Regarding the former two items, results were compared with those from megakaryoblastic crisis of chronic myelocytic leukemia (CML-MkBC) and transient myeloproliferative disorder in Down syndrome (DS-TMD), which are thought to be multipotential stem cell disorders. Among 18 patients with AMkL, three, all complicating myelofibrosis, had marked myelodysplastic changes of erythroid series and/or granulocytic series. In 4 out of 7 patients with CML-MkBC, 5 out of 8 patients with DS-TMD, and 7 out of 18 patients with AMkL, MPO-positive blasts, even though rare, were observed in addition to PPO-positive blasts. All except one of these patients with AMkL also showed complicating myelofibrosis. In one case of AMkL with myelofibrosis, chromosomal analysis of cultured cells of individual colonies revealed that all the analysable metaphases from both CFU-GM and BFU-E had the same chromosomal abnormality as megakaryoblasts. This study has clarified that a considerable proportion of AMkL cases, particularly those with complicating myelofibrosis or showing acute myelofibrosis, arise against the background of a multipotential stem cell disorder, even if blasts are exclusively megakaryocytic in phenotype.

Stability of human interferon-beta 1: oligomeric human interferon-beta 1 is inactive but is reactivated by monomerization

Human interferon-beta 1 is extremely stable is a low ionic strength solution of pH 2 such as 10 mM HCl at 37 degrees C. However, the presence of 0.15 M NaCl led to a remarkable loss of antiviral activity. The molecular-sieve high-performance liquid chromatography revealed that, whereas completely active human interferon-beta 1 eluted as a 25 kDa species (monomeric form), the inactivated preparation eluted primarily as a 90 kDa species (oligomeric form). The specific activity (units per mg protein) of the oligomeric form was approx. 10% of that of the monomeric form. This observation shows that oligomeric human interferon-beta 1 is apparently in an inactive form. When the oligomeric eluate was resolved by polyacrylamide gel containing sodium dodecyl sulphate (SDS), it appeared to be monomeric under non-reducing conditions. Monomerization of the oligomeric human interferon-beta 1 by treatment with 1% SDS, fully regenerated its antiviral activity. These results suggest that the inactivation of the human interferon-beta 1 preparation was caused by its oligomerization via hydrophobic interactions without the formation of intermolecular disulphide bonds. These oligomers can be dissociated by SDS to restore biological activity.

Characterization of four different mammalian-cell-derived recombinant human interferon-beta 1s. Identical polypeptides and non-identical carbohydrate moieties compared to natural ones

In order to evaluate the structural identification of various recombinant human interferon-beta 1s, the recombinant proteins were produced in four different mammalian cells (human PC12 and PC8 lung adenocarcinoma cells, Chinese hamster ovary cells and mouse C127 cells) and characterized. Each mammalian-cell-derived recombinant human interferon-beta 1 represented a single band of 23 kDa on sodium dodecyl sulphate/polyacrylamide gel electrophoresis, the same molecular mass as fibroblast-derived natural human interferon-beta 1. Specific activities, amino acid compositions, amino-terminal sequences, peptide maps on C18 reversed-phase high-performance liquid chromatography and circular dichroic spectra of recombinant proteins were in good agreement with natural ones. On the other hand, the patterns of isoelectric focusing were different between mammalian-cell-derived recombinant human interferon-beta 1s and natural human interferon-beta 1. Sugar composition analysis revealed that the recombinant protein from Chinese hamster ovary cells has a similar sugar composition to that of natural protein and the other recombinant proteins have increased amounts of galactose and glucosamine in comparison to the natural protein. Furthermore, there is no galactosamine in the natural protein, while small amounts of galactosamine were detected in the oligosaccharides released from PC8- and C127-derived recombinant proteins by N-glycanase. These results indicate that mammalian-cell-derived recombinant human interferon-beta 1s have identical polypeptides to those of natural human interferon-beta 1 but their carbohydrate moieties, including unusual N-linked oligosaccharides, are individually different from natural ones and depend on the host cell.

Comparative study of the asparagine-linked sugar chains of natural human interferon-beta 1 and recombinant human interferon-beta 1 produced by three different mammalian cells

The asparagine-linked sugar chains of natural interferon-beta 1 secreted from human foreskin fibroblasts by poly I:poly C induction and of three recombinant human interferon-beta 1 produced by Chinese hamster ovary cells, mouse epithelial cells (C127), and human lung adenocarcinoma cells (PC8) were released quantitatively as oligosaccharides by hydrazinolysis followed by N-acetylation. After being reduced with either NaB3H4 or NaB2H4, their structures were comparatively analyzed. More than 80% of the sugar chains of natural interferon-beta 1 occur as biantennary complex-type sugar chains, approximately 10% of which contain N-acetyllactosamine repeating structure in their outer chain moieties. The remainders are 2,4- and 2,6-branched triantennary complex-type sugar chains. The sugar chains of the recombinant interferon-beta 1 derived from Chinese hamster ovary cells were very similar to those of its natural counterpart. In contrast, two other recombinant proteins contain quite different sugar chains. The protein derived from C127 cells contains complex-type sugar chains with the Gal alpha 1----3Gal beta 1----4GlcNAc group in their outer chain moieties. Their sialic acid residues occur solely as the Sia alpha 2----6Gal group, where Sia is sialic acid. In contrast, the sialic acid residues of other interferon-beta 1 occur as the Sia alpha 2----3Gal group only. A part of the sugar chains of the protein derived from PC8 cells contains bisecting N-acetylglucosamine residue in addition to the Gal alpha 1----3Gal beta 1----4GlcNAc group.

Disulfide bond interchange in Escherichia coli-derived recombinant human interferon-beta 1 under denaturing conditions

Disulfide bond interchange has been pointed out as a considerable problem in preparing recombinant proteins from Escherichia coli cells. This has been reported in the system of reducing denaturation followed by a refolding process, where incorrectly folded molecules are sometimes produced. As the possibility of disulfide bond interchange may also arise in the cytoplasm of E. coli cells, the state of sulfhydryl groups of recombinant proteins obtained from a nonreducing and nondenaturing process should be examined. The state of sulfhydryl groups of E. coli-derived recombinant human interferon-beta 1, which had been purified under nonreducing and nondenaturing conditions, was examined by using the N-(7-dimethylamino-4-methylcoumarinyl)maleimide (DACM) labeling technique. Among the three cysteine residues in E. coli-derived human interferon-beta 1, the 17th cysteine was identified as being unpaired, as in the natural molecule. However, it was found that three isomers of the recombinant protein could be formed when the protein was denatured with 6 M guanidine hydrochloride. These three isomers were identified as having unpaired cysteine residues at positions 17, 31, and 141, respectively. These results indicate that disulfide bond interchange occurs in E. coli-derived recombinant human interferon-beta 1 under denaturing conditions in spite of the absence of a reducing agent.

Structural characterization of fibroblast human interferon-beta 1

The complete amino acid sequence of fibroblast human interferon-beta 1 (IFN-beta 1) was determined, and the higher-order structure of the protein was characterized with Raman spectroscopy. That amino acid sequence was identical to the entire sequence deduced from the cDNA nucleotide sequence, showing there are no proteolytic cleavages of carboxy-terminal residues in contrast to natural human IFN-alpha and natural human IFN-gamma. The N-glycosylation site was confirmed as Asn-80 by the detection of glucosamines in the peptide containing Asn-80. An S-carboxymethyl Cys-17 was detected in the S-carboxymethylated protein, suggesting that Cys-17 is unpaired. Raman spectra indicated a predominance of alpha-helical backbone and three Cys residues in this protein form, one unpaired Cys residue and one disulfide bond. These results provide some evidence for the primary and higher-order structures of natural IFN-beta 1 so far predicted.

Comparison of intermittent or continuous methotrexate plus 6-mercaptopurine in regimens for standard-risk acute lymphoblastic leukemia in childhood (JCCLSG-S811). The Japanese Children's Cancer and Leukemia Study Group

From 1981 to 1983, 131 previously untreated patients with acute lymphoblastic leukemia (ALL) standard-risk group were entered to the protocol JCCLSG-S811. Of 119 eligible patients, 115 (96.6%) attained complete remission by treatment with prednisone (PRD) plus vincristine (VCR) or vindesine (VDS). After preventive central nervous system (CNS) therapy including 18 Gy cranial irradiation and three doses of intrathecal methotrexate (MTX), the patients were assigned randomly to the two maintenance chemotherapies, Regimen A and Regimen B. Regimen A (intermittent regimen) consisted of PRD (120 mg/m2/day by mouth for 5 days) plus 6-mercaptopurine (6MP) (175 mg/m2/day by mouth for 5 days) plus VCR (2.0 mg/m2 intravenously) alternating biweekly with MTX (225 mg/m2 intravenously). Regimen B (continuous regimen) consisted of 6MP (50 mg/m2/day by mouth) plus MTX (20 mg/m2/week by mouth) combined with pulses of PRD and VCR (the same dosages as Regimen A) every 4 weeks. As the late intensification therapy (LIT), five courses of high-dose MTX (2000 mg/m2 per dose per week intravenously for three doses every 12 weeks) with leucovorin rescue were administered to all patients who were in continuous complete remission (CCR) for more than 2 years. Sixty and 55 patients, respectively, were registered in Regimen A and B. The CCR rates in Regimen A and B were 75.1% +/- 5.8% (mean +/- 1 SE) and 49.7% +/- 7.3% (P less than 0.01) at 4 years, and 72.1% +/- 6.3% and 49.7% +/- 7.3% (P less than 0.05) at 5 years, respectively. In Regimen B, CNS and testicular relapses increased after 3 years of CCR. In addition, the patients in Regimen B had a much higher incidence of infections than Regimen A. The LIT did not seem to have important effects on the duration of CCR. From these data we conclude that the intermittent cyclic regimen of 6MP and MTX may be more effective as compared to the continuous administration of these drugs in the maintenance chemotherapy.

Monoclonal antibody to human beta interferon: characterization and application

Seven stable mouse hybridomas secreting monoclonal antibodies to human fibroblast beta interferon (IFN-beta) were isolated, all seven of which belonged to IgGl subclass and kappa type. While neutralizing the antiviral activity of human fibroblast IFN-beta, they failed to neutralized both that of human IFN-alpha and human IFN-gamma. These monoclonal antibodies neutralized the antiviral activity of human fibroblast IFN-beta but not that of human IFN-alpha and IFN-gamma. Two of the seven monoclonal antibodies, YSB-1 and YSB-2, showed particularly high neutralization titers in the ascitic fluid. Monoclonal antibodies were purified from cultures of hybridoma grown in a serum-free medium. The purified monoclonal antibodies, YSB-1(5 micrograms/ml) and YSB-2(1 microgram/ml), neutralized IFN-beta from 10EU/ml to 1EU/ml. Human fibroblast IFN-beta was purified to 3.5 X 10(7) IU/mg protein (1.0 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-2) affinity column chromatography, whereas human recombinant IFN-beta obtained from E.coli was also purified to 6.5 X 10(7) IU/mg protein (1.1 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-1) affinity column chromatography.

Characterization of E. coli-derived recombinant human interferon-beta as compared with fibroblast human interferon-beta

Homogeneous E. coli-derived recombinant human interferon-beta (E. coli-rHuIFN-beta) was characterized in order to elucidate its physicochemical properties, as compared with those of fibroblast human interferon-beta (fibroblast HuIFN-beta). Purified E. coli-rHuIFN-beta and fibroblast HuIFN-beta exhibited a single band of Mr 19,000 and 23,000, respectively, on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The primary structure of E. coli-rHuIFN-beta was identical to the prediction from the cDNA sequence. Furthermore, both the circular dichroism (CD) spectra and the 1H nuclear magnetic resonance (NMR) spectra of E. coli-rHuIFN-beta and fibroblast HuIFN-beta at pH 6.8 were closely similar to each other. On the other hand, on reverse-phase high-performance liquid chromatography (HPLC) using a C18 column, the retention time of E. coli-rHuIFN-beta was longer than that of fibroblast HuIFN-beta. Moreover, although the isoelectric point of E. coli-rHuIFN-beta was pH 8.9, purified fibroblast HuIFN-beta exhibited multiple isoelectric points, probably due to heterogeneity of the carbohydrate moiety. These results indicate that the E. coli-rHuIFN-beta polypeptide folds similarly to fibroblast HuIFN-beta, and the carbohydrate moiety of natural HuIFN-beta has little influence on higher-order structure but does influence the hydrophobic and the electrostatic properties of the molecule.

Purification and characterization of recombinant mouse interferon-beta

Recombinant mouse interferon-beta (rMuIFN-beta) produced in Escherichia coli was purified to homogeneity and characterized. The purified protein exhibited a single band of Mr 19,900 on SDS-polyacrylamide gel electrophoresis under both reducing and nonreducing conditions, and also exhibited a single band on native polyacrylamide gel electrophoresis at pH 4.3. The observed molecular weight corresponded to that of the polypeptide moiety of natural MuIFN-beta of Mr 19,700. The amino acid composition and the amino-terminal sequence of the purified rMuIFN-beta were identical to those predicted from cDNA sequence. These results indicate that the purified protein is a nonglycosylated MuIFN-beta, which forms no disulfide-linked dimer and probably exists as a monomeric form.

Conformations of fibroblast and E. coli-derived recombinant human interferon-beta s as studied by nuclear magnetic resonance and circular dichroism

The conformations of fibroblast and E. coli-derived recombinant human interferon-beta s were studied by circular dichroism and nuclear magnetic resonance spectroscopy in the acidic pH region of 4.6 to 1.6. Both interferons have very similar conformations with high alpha-helix contents (approximately 70%). These results suggest that glycosylation does not appreciably change the conformation of human interferon-beta. Moreover, a slow conformational change is observed below pH 2.0, which induces the disruption of beta-sheets.

Interferon production with multitray culture system on a large scale

A multitray culture system was devised for cell culture and interferon (IFN) production on a large scale. The system consisted of a cell culture apparatus which has stacked multitrays and a reservoir. All components of the system were made of nontoxic, nonmutagenic, washable, and autoclavable materials, so that the system can be repetitively used in suitable condition for cultivations of anchorage-dependent cells with low running cost. Large quantities of mouse IFN (containing both MuIFN-alpha and MuIFN-beta) from mouse L cells and human beta interferon (HuIFN-beta) from human fibroblast cells, respectively, were obtained very efficiently using this system in comparison with roller bottle, bulk culture vessel, and microcarrier systems.

Familial leukemia. HLA system and leukemia predisposition in a family

Four cases of acute lymphocytic leukemia occurred in a family comprising 30 members. Genetic and cytogenetic studies showed a possible linkage between an HLA haplotype and the leukemia predisposition that was suggested by site-directed chromosome rearrangements in cultured skin fibroblasts. The possession of genetic markers, other than HLA types, could not be linked to the occurrence of leukemia in the family. These findings suggest that the major histocompatibility complex or gene(s) linked to it may have played a part in the pathogenesis of the leukemic process in this family.

Site-directed chromosome rearrangements in skin fibroblasts from persons carrying genes for hereditary neoplasms

Chromosomal variability was studied in cultured skin fibroblasts in members of two unrelated families associated with hereditary neoplasms, one with familial childhood leukemia and the other with medullary thyroid cancer syndrome. Nonconstitutional chromosome rearrangements occurred with consistent frequency in the patients and obligate carriers. The G-banding analysis showed that th chromosome rearrangements were not random, and site of rearrangements tended to cluster to band p22 of chromosome 1 in the carriers of childhood leukemia gene and to band q23 of chromosome 17 in the patient with medullary thyroid cancer. The de novo rearrangements of chromosomes and their tendency to cluster to particular chromosomal sites strongly point to the possibility that the procancer type-dominant mutations responsible for these diseases have a mutator function analogous to the property of some insertion mutations or transposable elements.