Correction: Histone Demethylase JMJD2B Functions as a Co-Factor of Estrogen Receptor in Breast Cancer Proliferation and Mammary Gland Development

[This corrects the article DOI: 10.1371/journal.pone.0017830.].

Modification of the HLA-A*24:02 Peptide Binding Pocket Enhances Cognate Peptide-Binding Capacity and Antigen-Specific T Cell Activation

The immunogenicity of a T cell Ag is correlated with the ability of its antigenic epitope to bind HLA and be stably presented to T cells. This presents a challenge for the development of effective cancer immunotherapies, as many self-derived tumor-associated epitopes elicit weak T cell responses, in part due to weak binding affinity to HLA. Traditional methods to increase peptide–HLA binding affinity involve modifying the peptide to reflect HLA allele binding preferences. Using a different approach, we sought to analyze whether the immunogenicity of wild-type peptides could be altered through modification of the HLA binding pocket. After analyzing HLA class I peptide binding pocket alignments, we identified an alanine 81 to leucine (A81L) modification within the F binding pocket of HLA-A*24:02 that was found to heighten the ability of artificial APCs to retain and present HLA-A*24:02–restricted peptides, resulting in increased T cell responses while retaining Ag specificity. This modification led to increased peptide exchange efficiencies for enhanced detection of low-avidity T cells and, when expressed on artificial APCs, resulted in greater expansion of Ag-specific T cells from melanoma-derived tumor-infiltrating lymphocytes. Our study provides an example of how modifications to the HLA binding pocket can enhance wild-type cognate peptide presentation to heighten T cell activation.

Affinity-matured HLA class II dimers for robust staining of antigen-specific CD4+ T cells

Peptide-major histocompatibility complex (pMHC) multimers enable the detection of antigen-specific T cells in studies ranging from vaccine efficacy to cancer immunotherapy. However, this technology is unreliable when applied to pMHC class II for the detection of CD4⁺ T cells. Here, using a combination of molecular biological and immunological techniques, we cloned sequences encoding human leukocyte antigen (HLA)-DP, HLA-DQ and HLA-DR molecules with enhanced CD4 binding affinity (with a K_d of 8.9 ± 1.1 µM between CD4 and affinity-matured HLA-DP4) and produced affinity-matured class II dimers that stain antigen-specific T cells better than conventional multimers in both in vitro and ex vivo analyses. Using a comprehensive library of dimers for HLA-DP4, which is the most frequent HLA allele in many ancestry groups, we mapped 103 HLA-DP4-restricted epitopes derived from diverse tumor-associated antigens and cloned the cognate T-cell antigen receptor (TCR) genes from in vitro-stimulated CD4⁺ T cells. The availability of affinity-matured class II dimers across HLA-DP, HLA-DQ and HLA-DR alleles will aid in the investigation of human CD4⁺ T-cell responses.

Genetic Ablation of HLA Class I, Class II, and the T-cell Receptor Enables Allogeneic T Cells to Be Used for Adoptive T-cell Therapy

Adoptive immunotherapy can induce sustained therapeutic effects in some cancers. Antitumor T-cell grafts are often individually prepared in vitro from autologous T cells, which requires an intensive workload and increased costs. The quality of the generated T cells can also be variable, which affects the therapy's antitumor efficacy and toxicity. Standardized production of antitumor T-cell grafts from third-party donors will enable widespread use of this modality if allogeneic T-cell responses are effectively controlled. Here, we generated HLA class I, HLA class II, and T-cell receptor (TCR) triple-knockout (tKO) T cells by simultaneous knockout of the B2M, CIITA, and TRAC genes through Cas9/sgRNA ribonucleoprotein electroporation. Although HLA-deficient T cells were targeted by natural killer cells, they persisted better than HLA-sufficient T cells in the presence of allogeneic peripheral blood mononuclear cells (PBMC) in immunodeficient mice. When transduced with a CD19 chimeric antigen receptor (CAR) and stimulated by tumor cells, tKO CAR-T cells persisted better when cultured with allogeneic PBMCs compared with TRAC and B2M double-knockout T cells. The CD19 tKO CAR-T cells did not induce graft-versus-host disease but retained antitumor responses. These results demonstrated the benefit of HLA class I, HLA class II, and TCR deletion in enabling allogeneic-sourced T cells to be used for off-the-shelf adoptive immunotherapy.

Landscape mapping of shared antigenic epitopes and their cognate TCRs of tumor-infiltrating T lymphocytes in melanoma

HLA-restricted T cell responses can induce antitumor effects in cancer patients. Previous human T cell research has largely focused on the few HLA alleles prevalent in a subset of ethnic groups. Here, using a panel of newly developed peptide-exchangeable peptide/HLA multimers and artificial antigen-presenting cells for 25 different class I alleles and greater than 800 peptides, we systematically and comprehensively mapped shared antigenic epitopes recognized by tumor-infiltrating T lymphocytes (TILs) from eight melanoma patients for all their class I alleles. We were able to determine the specificity, on average, of 12.2% of the TILs recognizing a mean of 3.1 shared antigen-derived epitopes across HLA-A, B, and C. Furthermore, we isolated a number of cognate T cell receptor genes with tumor reactivity. Our novel strategy allows for a more complete examination of the immune response and development of novel cancer immunotherapy not limited by HLA allele prevalence or tumor mutation burden.

The immune system is the body’s way of defending itself, offering protection against diseases such as cancer. But to remove the cancer cells, the immune system must be able to identify them as different from the rest of the body. All cells break down proteins into shorter fragments, known as peptides, that are displayed on the cell surface by a protein called human leukocyte antigen, HLA for short. Cancer cells display distinctive peptides on their surface as they generate different proteins to those of healthy cells. Immune cells called T cells use these abnormal peptides to identify the cancer so that it can be destroyed.

Sometimes T cells can lack the right equipment to detect abnormal peptides, allowing cancer cells to hide from the immune system. However, T cells can be trained through a treatment called immunotherapy, which provides T cells with new tools so that they can spot the peptides displayed by HLA on the previously ‘hidden’ cancer cells.

There are many different forms of HLA, each of which can display different peptides. Current research in immunotherapy commonly targets only a subset of HLA forms, and not all cancer patients have these types. This means that immunotherapy research is only likely to be of most benefit to a limited number of patients. Immunotherapy could be made effective for more people if new cancer peptides that are displayed by the other ‘under-represented’ forms of HLA were identified.

Murata, Nakatsugawa et al. have now used T cells that were taken from tumors in eight patients with melanoma, which is a type of skin cancer. A library of fluorescent HLA-peptides was generated – using a new, simplified methodology – with 25 forms of HLA that displayed over 800 peptides. T cells were then mixed with the library to identify which HLA-peptides they can target. As a result, Murata, Nakatsugawa et al. found the cancer targets of around 12% of the tumor-infiltrating T cells tested, including those from under-represented forms of HLA. Consequently, these findings could be used to develop new immunotherapies that can treat more patients.

Abstract 568: Decoding shared antigenic epitopes and their cognate TCR genes in melanoma TILs using a library of paired human cell-based pHLA multimers and artificial APCs

HLA-restricted T cell responses toward immunogenic peptides, whether mutated or non-mutated, can induce antitumor responses in patients with advanced cancer. The fact that potential non-mutated antigens are greater in number than mutated antigens by multiple orders of magnitude and the high polymorphism of HLA genes may have hampered comprehensive analyses of the specificity of antitumor T cell responses toward non-mutated antigens than mutated antigens. Unlike shared antigens, the vast majority of neoantigens are not shared and are unique to each patient. The elucidation of T cell epitopes derived from shared antigens may facilitate the robust development of an efficacious and safe adoptive T cell therapy that is readily available to a larger cohort of cancer patients. It is well established that melanoma tumor-infiltrating T lymphocytes (TILs) contain antitumor T cells that are specific for both non-mutated and mutated antigens. The adoptive transfer of TILs can induce sustained clinical responses in some patients with advanced melanoma. However, a precise and extensive understanding of the shared antigen targets of TILs has been lacking. In this study, TILs were isolated from 8 metastatic melanoma patients, polyclonally expanded in vitro, and their shared antigen specificities for all 45 (25 different) class I alleles were examined. The combination of structure-based analysis using human cell-based peptide/HLA (pHLA) multimers and functional analysis using artificial antigen-presenting cells (APCs) were used to determine antigen-specific T cell responses. We were able to determine the specificity of 12.2 ± 7.2% (mean ± SD, max 25.8%, min 4.6%) of CD8+ T cells in an expanded TIL culture toward 3.0 ± 1.8 (mean ± SD, max 6, min 1) previously known or novel peptides derived from shared antigens. Furthermore, we isolated a number of cognate TCR genes with potent tumor reactivity from the CD8+ T cells. The strategy employed in this study using a library of paired human cell-based pHLA multimers and artificial APCs has enabled us to decipher the antigen specificity of tumor-specific T cells for any given HLA class I allele, regardless of allele frequency and for an infinite number of peptides. It has also allowed us to build a large database of class I-restricted peptides and cognate tumor-reactive TCR genes at an unprecedented scale. This database will be a valuable tool in defining the immune response at the level of each individual cancer patient with precision as well as the identification and validation of biomarkers to aid in patient-based selection of a cancer immunotherapy regimen. Furthermore, this database will help the robust development of novel cancer vaccines and TCR gene therapies for patients with a low mutation burden.

Citation Format: Kenji Murata, Kayoko Saso, Linh T. Nguyen, Douglas Millar, Marcus O. Butler, Pamela S. Ohashi, Naoto Hirano. Decoding shared antigenic epitopes and their cognate TCR genes in melanoma TILs using a library of paired human cell-based pHLA multimers and artificial APCs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 568.

JMJD2B/KDM4B inactivation in adipose tissues accelerates obesity and systemic metabolic abnormalities

Obesity is a serious global health issue; however, the roles of genetics and epigenetics in the onset and progression of obesity are still not completely understood. The aim of this study was to determine the role of Kdm4b, which belongs to a subfamily of histone demethylases, in adipogenesis and fat metabolism in vivo. We established conditional Kdm4b knockout mice. Inactivation of Kdm4b in adipocytes (K4bKO) induced profound obesity in mice on a high fat diet (HFD). The HFD-fed K4bKO mice exhibited an increased volume of fat mass and higher expression levels of adipogenesis-related genes. In contrast, the genes involved in energy expenditure and mitochondrial functions were down-regulated. Supporting these findings, the energy expenditure of Kdm4b-deficient cells was markedly decreased. In addition, progression of glucose intolerance and hepatic steatosis with hepatocellular damages was observed. These data indicate that Kdm4b is a critical regulator of systemic metabolism via enhancing energy expenditure in adipocytes.

DOT1L inhibition attenuates graft-versus-host disease by allogeneic T cells in adoptive immunotherapy models

Adoptive T-cell therapy is a promising therapeutic approach for cancer patients. The use of allogeneic T-cell grafts will improve its applicability and versatility provided that inherent allogeneic responses are controlled. T-cell activation is finely regulated by multiple signaling molecules that are transcriptionally controlled by epigenetic mechanisms. Here we report that inhibiting DOT1L, a histone H3-lysine 79 methyltransferase, alleviates allogeneic T-cell responses. DOT1L inhibition reduces miR-181a expression, which in turn increases the ERK phosphatase DUSP6 expression and selectively ameliorates low-avidity T-cell responses through globally suppressing T-cell activation-induced gene expression alterations. The inhibition of DOT1L or DUSP6 overexpression in T cells attenuates the development of graft-versus-host disease, while retaining potent antitumor activity in xenogeneic and allogeneic adoptive immunotherapy models. These results suggest that DOT1L inhibition may enable the safe and effective use of allogeneic antitumor T cells by suppressing unwanted immunological reactions in adoptive immunotherapy.

Mechanisms underlying the lack of endogenous processing and CLIP-mediated binding of the invariant chain by HLA-DP84Gly

While the principles of classical antigen presentation via MHC class II are well-established, the mechanisms for the many routes of cross-presentation by which endogenous antigens become associated with class II molecules are not fully understood. We have recently demonstrated that the single amino acid polymorphism HLA-DPβ^84Gly (DP^84Gly) is critical to abrogate class II invariant chain associated peptide (CLIP) region-mediated binding of invariant chain (Ii) to DP, allowing endoplasmic reticulum (ER)-resident endogenous antigens to constitutively associate with DP^84Gly such as DP4. In this study, we demonstrate that both the CLIP and N-terminal non-CLIP Ii regions cooperatively generate an Ii conformation that cannot associate with DP^84Gly via the CLIP region. We also demonstrate the ability of DP4 to efficiently process and present antigens encoded in place of CLIP in a chimeric Ii, regardless of wild type Ii and HLA-DM expression. These data highlight the complex interplay between DP polymorphisms and the multiple Ii regions that cooperatively regulate this association, ultimately controlling the presentation of endogenous antigens on DP molecules. These results may also offer a mechanistic explanation for recent studies identifying the differential effects between DP^84Gly and DP^84Asp as clinically relevant in human disease.

A Subset of Human Autoreactive CD1c-Restricted T Cells Preferentially Expresses TRBV4-1+ TCRs

In humans, a substantial portion of T cells recognize lipids presented by the monomorphic CD1 proteins. Recent studies have revealed the molecular basis of mycobacterial lipid recognition by CD1c-restricted T cells. Subsets of CD1c-restricted T cells recognize self-lipids in addition to foreign lipids, which may have implications in human diseases involving autoimmunity and malignancy. However, the molecular identity of these self-reactive T cells remains largely elusive. In this study, using a novel CD1c⁺ artificial APC (aAPC)-based system, we isolated human CD1c-restricted autoreactive T cells and characterized them at the molecular level. By using the human cell line K562, which is deficient in MHC class I/II and CD1 expression, we generated an aAPC expressing CD1c as the sole Ag-presenting molecule. When stimulated with this CD1c⁺ aAPC presenting endogenous lipids, a subpopulation of primary CD4⁺ T cells from multiple donors was consistently activated, as measured by CD154 upregulation and cytokine production in a CD1c-specific manner. These activated CD4⁺ T cells preferentially expressed TRBV4-1⁺ TCRs. Clonotypic analyses of the reconstituted TRBV4-1⁺ TCR genes confirmed CD1c-restricted autoreactivity of this repertoire, and the strength of CD1c reactivity was influenced by the diversity of CDR3β sequences. Finally, alanine scanning of CDR1 and CDR2 sequences of TRBV4-1 revealed two unique residues, Arg³⁰ and Tyr⁵¹, as critical in conferring CD1c-restricted autoreactivity, thus elucidating the molecular basis of the observed V gene bias. These data provide new insights into the molecular identity of human autoreactive CD1c-restricted T cells.

HLA-DP84Gly constitutively presents endogenous peptides generated by the class I antigen processing pathway

Classical antigen processing leads to the presentation of antigenic peptides derived from endogenous and exogenous sources for MHC class I and class II molecules, respectively. Here we show that, unlike other class II molecules, prevalent HLA-DP molecules with β-chains encoding Gly84 (DP^84Gly) constitutively present endogenous peptides. DP^84Gly does not bind invariant chain (Ii) via the class II-associated invariant chain peptide (CLIP) region, nor does it present CLIP. However, Ii does facilitate the transport of DP^84Gly from the endoplasmic reticulum (ER) to the endosomal/lysosomal pathway by transiently binding DP^84Gly via a non-CLIP region(s) in a pH-sensitive manner. Accordingly, like class I, DP^84Gly constitutively presents endogenous peptides processed by the proteasome and transported to the ER by the transporter associated with antigen processing (TAP). Therefore, DP^84Gly, found only in common chimpanzees and humans, uniquely uses both class I and II antigen-processing pathways to present peptides derived from intracellular and extracellular sources.

Transient stimulation expands superior antitumor T cells for adoptive therapy

Adoptive cell therapy is a potentially curative therapeutic approach for patients with cancer. In this treatment modality, antitumor T cells are exponentially expanded in vitro prior to infusion. Importantly, the results of recent clinical trials suggest that the quality of expanded T cells critically affects their therapeutic efficacy. Although anti-CD3 mAb-based stimulation is widely used to expand T cells in vitro, a protocol to generate T cell grafts for optimal adoptive therapy has yet to be established. In this study, we investigated the differences between T cell stimulation mediated by anti-CD3/CD28 mAb-coated beads and cell-based artificial antigen-presenting cells (aAPCs) expressing CD3/CD28 counter-receptors. We found that transient stimulation with cell-based aAPCs, but not prolonged stimulation with beads, resulted in the superior expansion of CD8⁺ T cells. Transiently stimulated CD8⁺ T cells maintained a stem cell-like memory phenotype and were capable of secreting multiple cytokines significantly more efficiently than chronically stimulated T cells. Importantly, the chimeric antigen receptor-engineered antitumor CD8⁺ T cells expanded via transient stimulation demonstrated superior persistence and antitumor responses in adoptive immunotherapy mouse models. These results suggest that restrained stimulation is critical for generating T cell grafts for optimal adoptive immunotherapy for cancer.

Key Residues at Third CDR3β Position Impact Structure and Antigen Recognition of Human Invariant NK TCRs

The human invariant NK (iNK) TCR is largely composed of the invariant TCR Vα24-Jα18 chain and semivariant TCR Vβ11 chains with variable CDR3β sequences. The direct role of CDR3β in Ag recognition has been studied extensively. Although it was noted that CDR3β can interact with CDR3α, how this interaction might indirectly influence Ag recognition is not fully elucidated. We observed that the third position of Vβ11 CDR3 can encode an Arg or Ser residue as a result of somatic rearrangement. Clonotypic analysis of the two iNK TCR types with a single amino acid substitution revealed that the staining intensity by anti-Vα24 Abs depends on whether Ser or Arg is encoded. When stained with an anti-Vα24-Jα18 Ab, human primary invariant NKT cells could be divided into Vα24 low- and high-intensity subsets, and Arg-encoding TCR Vβ11 chains were more frequently isolated from the Vα24 low-intensity subpopulation compared with the Vα24 high-intensity subpopulation. The Arg/Ser substitution also influenced Ag recognition as determined by CD1d multimer staining and CD1d-restricted functional responses. Importantly, in silico modeling validated that this Ser-to-Arg mutation could alter the structure of the CDR3β loop, as well as the CDR3α loop. Collectively, these results indicate that the Arg/Ser encoded at the third CDR3β residue can effectively modulate the overall structure of, and Ag recognition by, human iNK TCRs.

Generating De Novo Antigen-specific Human T Cell Receptors by Retroviral Transduction of Centric Hemichain

T cell receptors (TCRs) are used clinically to direct the specificity of T cells to target tumors as a promising modality of immunotherapy. Therefore, cloning TCRs specific for various tumor-associated antigens has been the goal of many studies. To elicit an effective T cell response, the TCR must recognize the target antigen with optimal affinity. However, cloning such TCRs has been a challenge and many available TCRs possess sub-optimal affinity for the cognate antigen. In this protocol, we describe a method of cloning de novo high affinity antigen-specific TCRs using existing TCRs by exploiting hemichain centricity. It is known that for some TCRs, each TCRα or TCRβ hemichain do not contribute equally to antigen recognition, and the dominant hemichain is referred to as the centric hemichain. We have shown that by pairing the centric hemichain with counter-chains differing from the original counter-chain, we are able to maintain the antigen specificity, while modulating its interaction strength for the cognate antigen. Thus, the therapeutic potential of a given TCR can be improved by optimizing the pairing between the centric and counter hemichains.

BET bromodomain inhibition enhances T cell persistence and function in adoptive immunotherapy models

Adoptive immunotherapy is a potentially curative therapeutic approach for patients with advanced cancer. However, the in vitro expansion of antitumor T cells prior to infusion inevitably incurs differentiation towards effector T cells and impairs persistence following adoptive transfer. Epigenetic profiles regulate gene expression of key transcription factors over the course of immune cell differentiation, proliferation, and function. Using comprehensive screening of chemical probes with defined epigenetic targets, we found that JQ1, an inhibitor of bromodomain and extra-terminal motif (BET) proteins, maintained CD8+ T cells with functional properties of stem cell-like and central memory T cells. Mechanistically, the BET protein BRD4 directly regulated expression of the transcription factor BATF in CD8+ T cells, which was associated with differentiation of T cells into an effector memory phenotype. JQ1-treated T cells showed enhanced persistence and antitumor effects in murine T cell receptor and chimeric antigen receptor gene therapy models. Furthermore, we found that histone acetyltransferase p300 supported the recruitment of BRD4 to the BATF promoter region, and p300 inhibition similarly augmented antitumor effects of the adoptively transferred T cells. These results demonstrate that targeting the BRD4-p300 signaling cascade supports the generation of superior antitumor T cell grafts for adoptive immunotherapy.

CD4(+) and CD8(+) TCRβ repertoires possess different potentials to generate extraordinarily high-avidity T cells

Recent high throughput sequencing analysis has revealed that the TCRβ repertoire is largely different between CD8(+) and CD4(+) T cells. Here, we show that the transduction of SIG35α, the public chain-centric HLA-A*02:01(A2)/MART127-35 TCRα hemichain, conferred A2/MART127-35 reactivity to a substantial subset of both CD8(+) and CD4(+) T cells regardless of their HLA-A2 positivity. T cells individually reconstituted with SIG35α and different A2/MART127-35 TCRβ genes isolated from CD4(+) or CD8(+) T cells exhibited a wide range of avidity. Surprisingly, approximately half of the A2/MART127-35 TCRs derived from CD4(+) T cells, but none from CD8(+) T cells, were stained by A2/MART127-35 monomer and possessed broader cross-reactivity. Our results suggest that the differences in the primary structure of peripheral CD4(+) and CD8(+) TCRβ repertoire indeed result in the differences in their ability to form extraordinarily high avidity T cells which would otherwise have been deleted by central tolerance.

The Histone Variant MacroH2A1.2 Is Necessary for the Activation of Muscle Enhancers and Recruitment of the Transcription Factor Pbx1

Histone variants complement and integrate histone post-translational modifications in regulating transcription. The histone variant macroH2A1 (mH2A1) is almost three times the size of its canonical H2A counterpart, due to the presence of an ∼25 kDa evolutionarily conserved non-histone macro domain. Strikingly, mH2A1 can mediate both gene repression and activation. However, the molecular determinants conferring these alternative functions remain elusive. Here, we report that mH2A1.2 is required for the activation of the myogenic gene regulatory network and muscle cell differentiation. H3K27 acetylation at prospective enhancers is exquisitely sensitive to mH2A1.2, indicating a role of mH2A1.2 in imparting enhancer activation. Both H3K27 acetylation and recruitment of the transcription factor Pbx1 at prospective enhancers are regulated by mH2A1.2. Overall, our findings indicate a role of mH2A1.2 in marking regulatory regions for activation.

Histone demethylase JMJD2B functions as a co-factor of estrogen receptor in breast cancer proliferation and mammary gland development

Estrogen is a key regulator of normal function of female reproductive system and plays a pivotal role in the development and progression of breast cancer. Here, we demonstrate that JMJD2B (also known as KDM4B) constitutes a key component of the estrogen signaling pathway. JMJD2B is expressed in a high proportion of human breast tumors, and that expression levels significantly correlate with estrogen receptor (ER) positivity. In addition, 17-beta-estradiol (E2) induces JMJD2B expression in an ERα dependent manner. JMJD2B interacts with ERα and components of the SWI/SNF-B chromatin remodeling complex. JMJD2B is recruited to ERα target sites, demethylates H3K9me3 and facilitates transcription of ER responsive genes including MYB, MYC and CCND1. As a consequence, knockdown of JMJD2B severely impairs estrogen-induced cell proliferation and the tumor formation capacity of breast cancer cells. Furthermore, Jmjd2b-deletion in mammary epithelial cells exhibits delayed mammary gland development in female mice. Taken together, these findings suggest an essential role for JMJD2B in the estrogen signaling, and identify JMJD2B as a potential therapeutic target in breast cancer.

Defective FESTA/EAF2-mediated transcriptional activation in S-II-deficient embryonic stem cells

S-II is a transcription stimulation factor that enhances RNA synthesis by RNA polymerase II in vitro. To elucidate the function of S-II in transcriptional activation in mammalian cells, we generated an S-II-deficient murine embryonic stem (ES) cell line, DKO20, through targeted gene disruption. The DKO20 cells were viable, grew normally, and had a stable karyotype. The ability to evoke transcriptional activation of hsp70 and c-fos genes was not significantly altered in DKO20. In contrast, transcriptional activation mediated by FESTA/EAF2, a transcription factor that interacts with S-II, was decreased in DKO20 cells. The reduced transactivation potential of FESTA/EAF2 was rescued by introducing the wild-type S-II gene in DKO20. The amino-terminal region of S-II, a binding surface for FESTA/EAF2, was essential for the recovery. These results suggest that S-II is selectively required for positive transcriptional regulation of a subset of genes in murine ES cells.

Transcription elongation factor S-II is required for definitive hematopoiesis

Transcription elongation factor S-II/TFIIS promotes readthrough of transcriptional blocks by stimulating nascent RNA cleavage activity of RNA polymerase II in vitro. The biologic significance of S-II function in higher eukaryotes, however, remains unclear. To determine its role in mammalian development, we generated S-II-deficient mice through targeted gene disruption. Homozygous null mutants died at midgestation with marked pallor, suggesting severe anemia. S-II(-/-) embryos had a decreased number of definitive erythrocytes in the peripheral blood and disturbed erythroblast differentiation in fetal liver. There was a dramatic increase in apoptotic cells in S-II(-/-) fetal liver, which was consistent with a reduction in Bcl-x(L) gene expression. The presence of phenotypically defined hematopoietic stem cells and in vitro colony-forming hematopoietic progenitors in S-II(-/-) fetal liver indicates that S-II is dispensable for the generation and differentiation of hematopoietic stem cells. S-II-deficient fetal liver cells, however, exhibited a loss of long-term repopulating potential when transplanted into lethally irradiated adult mice, indicating that S-II deficiency causes an intrinsic defect in the self-renewal of hematopoietic stem cells. Thus, S-II has critical and nonredundant roles in definitive hematopoiesis.

Cytogenetic studies of Hynobiidae (Urodela)XVIII. A ZZ/ZW sex-determining mechanism in a hynobiid salamander species, Hynobius tokyoensis Tago

The karyotype of Hynobius tokyoensis (2n = 56) was analyzed using three kinds of banding methods to determine the morphological differentiation of the sex chromosomes of this species. Salamanders and egg sacs were collected from seven localities around Tokyo, Japan. Of 28 chromosome pairs, microchromosome No. 21 was identified as a ZZ/ZW-type sex chromosome. The Z chromosome was acrocentric, whereas the W chromosome was submetacentric, with a heterochromatic, elongated short arm. Interestingly, the W chromosome is of three distinct types, W(A), W(B), and W(C), based on R-banding and Ag-NOR patterns. W(A) was detected in five populations from southern habitats, whereas W(B) and W(C) were detected in one population each from northern habitats. W(A), W(B), and W(C) were all found to carry Ag-NORs on their heterochromatic short arms. Considering the karyotypes of other species belonging to the same genus, we discuss the evolution of the sex chromosomes of H. tokyoensis.

Identification of a novel tissue-specific transcriptional activator FESTA as a protein that interacts with the transcription elongation factor S-II

Transcription elongation factor S-II was originally purified as a specific stimulator of transcription by RNA polymerase II. Recent studies suggest that S-II participates in gene-specific transcriptional activation in vivo, despite the fact that it directly binds RNA polymerase II and does not recognize specific DNA sequences. In this study, under the hypothesis that S-II requires co-factors to regulate the expression of specific-genes in vivo, we searched for factors that directly interact with S-II using a yeast two-hybrid system, and isolated a novel nuclear protein, FESTA. FESTA is expressed specifically in kidney and spleen, supporting our notion that S-II participates in gene-specific regulation. Two mRNA isoforms of FESTA encoding proteins with different sizes were identified and named FESTA-S and FESTA-L. FESTA contains a serine-rich region and a C-terminal tail that are highly similar to those of the ELL-associated factor EAF1. Reporter gene assays indicated that both GAL4-FESTA-S and GAL4-FESTA-L fusion proteins have trans-activating ability. Furthermore, deletion of the C-terminal tail of FESTA dramatically reduced its trans-activating ability and abolished its interaction with S-II. This study is the first report of a transcriptional activator that directly interacts with S-II and contains a transcriptional activation domain that cooperates with S-II via direct interaction.

Th1/Th2 cytokine profiles and their relationship to clinical features in patients with chronic hepatitis C virus infection

PURPOSE

An imbalance in helper T-cell type 1 (Th1) and type 2 (Th2) cytokines is suggested to play an important role in the pathogenesis of chronic viral infections, but this issue is not resolved in patients with hepatitis C virus (HCV) infection. The aim of this study was to clarify the relationship between the balance of Th1 and Th2 cytokines and liver damage.

METHODS

We investigated cytokine levels in the peripheral blood and liver tissue of patients with chronic HCV infection (n = 59) by three different methods; we used flow cytometry to detect intracellular cytokines, and we measured cytokine titers in sera and in the supernatants of lymphocyte cultures with enzyme-linked immunosorbent assays (ELISAs).

RESULTS

In both CD4+ and CD8+ cells, interferon (IFN) gamma-producing cell populations increased, while there was no difference in interleukin (IL)-10 production, indicating a shift to a Th1 cytokine profile with the progression of liver disease. With respect to the ratio of IFN-gamma to IL-10, a correlation was found in CD4+ cells between peripheral blood and liver tissue (r = 0.98; P = 0.0011). Th1 cytokine was predominant in intrahepatic CD4+ cells, while it was predominant in peripheral blood CD8+ cells.

CONCLUSIONS

These findings indicate a correlation between dominant Th1 response and disease activity and progression. In addition, we suggest that intrahepatic CD4+ T cells play a pathogenetic role in the hepatic injury of HCV infection.

Percutaneous radiofrequency ablation therapy using a clustered electrode in the animal liver

BACKGROUND/AIMS

The aim of the present study was to examine the safety and effectiveness of percutaneous radiofrequency ablation therapy using a needle with cluster radiofrequency electrodes in an animal model.

METHODOLOGY

A total of 10 radiofrequency applications were performed in the normal liver of 5 domestic pigs with real-time ultrasonography until roll-off occurred two times. Aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase, and total bilirubin were evaluated before the procedure and 1 h, 24 h, and 7 days following percutaneous radiofrequency ablation therapy. The animals were euthanized 1 or 2 weeks after percutaneous radiofrequency ablation therapy, and the livers were removed for gross and histopathologic analysis for coagulation necrosis.

RESULTS

There were no complications in any of the experimental animals. Aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels peaked 24 h following percutaneous radiofrequency ablation therapy, and decreased with time thereafter. Total bilirubin was not elevated in any of the animals at any time. Macroscopic examination revealed that the area of coagulated necrosis was 28 x 21 mm when using a 2.0-cm needle, and 41 x 35 mm when using a 3.5-cm needle. Coagulation necrosis did not occur near large vessels. Microscopic examination of the fixed tissue revealed that coagulation necrosis occurred in preserving lobular structure.

CONCLUSIONS

Percutaneous radiofrequency ablation therapy using a clustered electrode is a safe and effective treatment for liver tumor. Incomplete coagulation necrosis, however, can occur when percutaneous radiofrequency ablation therapy is performed for tumors located near large vessels.

Diagnosis of small hepatocellular carcinoma--imaging diagnosis and significance of tumor biopsy

BACKGROUND/AIMS

To compare the effectiveness of different imaging modalities and the significance of tumor biopsy for diagnosing small hepatocellular carcinoma.

METHODOLOGY

Nodules (n = 352) with diameters of 30 mm or less newly detected by periodic ultrasonography and computed tomography in 234 patients with chronic liver disease were investigated with magnetic resonance imaging and digital subtraction angiography. These findings were compared with histologic findings. Histologic diagnoses were dysplastic nodule (n = 23), well-differentiated hepatocellular carcinoma (n = 163), moderately differentiated hepatocellular carcinoma (n = 159), and poorly differentiated hepatocellular carcinoma (n = 7). We compared three groups based on-diameters of 10, 11-20, and 21-30 mm. Nodules were diagnosed as hepatocellular carcinoma if they had hypervascular staining on digital subtraction angiography, hyperintensity on magnetic resonance T2-weighted images, arterial phase enhancement on enhanced magnetic resonance imaging, or low-high-low density on enhanced computed tomography.

RESULTS

Imaging alone was sufficient to diagnose hepatocellular carcinoma in 66.3% of the well-differentiated nodules and 91.6% of the moderately and poorly differentiated nodules (P < 0.001) The size of the nodule influenced the diagnosis of hepatocellular carcinoma by imaging alone in 65.5% (< or = 10 mm), 77.2% (11-20 mm), and 92.3% (21-30 mm) (< or = 10 vs. 21-30: P < 0.0001, 11-20 vs. 21-30: P < 0.0005). It was impossible to determine the degree of differentiation of the hepatocellular carcinoma by imaging alone.

CONCLUSIONS

The effectiveness of imaging for the diagnosis of hepatocellular carcinoma improved with decreasing differentiation and increasing diameter of the nodules. Tumor biopsy was required to make a histological accurate diagnosis.

Treatment of solitary small hepatocellular carcinoma: consideration of hepatic functional reserve and mode of recurrence

BACKGROUND/AIMS

Hepatocellular carcinoma (HCC) recurs frequently after initial treatment. The subsequent prognosis varies with the mode of recurrence. Some patients die of hepatic failure even though the HCC is controlled. We consider the clinical stage (CS), using the modified Child-Pugh classification, to be an important factor influencing the prognosis of these patients.

METHODOLOGY

To determine the most effective treatment for HCC, we examined 105 patients with solitary small HCC who were followed-up for more than 1 year after initial treatment. All of them were judged to be cured according to imaging or histological studies. The initial treatments were hepatic resection (n = 43), percutaneous ethanol injection therapy (PEIT, n = 33), and percutaneous microwave coagulation therapy (PMCT, n = 29). The modes of recurrence were divided into intrahepatic metastasis (IM) and multicentric occurrence (MO).

RESULTS

Prognosis of MO was superior to that of IM in CS I patients, but there was no difference in prognosis between these modes in CS II. The hepatic resection group had more MO recurrences in CS I patients and more IM recurrences in CS II patients. IM developed frequently after PEIT and PMCT, regardless of the CS. Prognosis with hepatic resection was superior to that of the other treatments in CS I patients, but there was no difference in prognosis among the 3 treatment modalities in CS II patients.

CONCLUSIONS

These data indicate that hepatic resection is the first choice for treating HCC in CS I patients, and that PEIT or PMCT is preferable for CS II patients.

Coexistence of primary biliary cirrhosis and myasthenia gravis: a case study

We present a case that suggests a relationship between primary biliary cirrhosis and myasthenia gravis. A 43-year-old Japanese woman was admitted to the Nagoya City University Medical School, First Department of Internal Medicine with abnormal liver function in August 1991. She had had ptosis of the right eye since 1990. She had not been treated for liver disease. Ptosis of the right eye and hepatomegaly were present. Serum laboratory examinations revealed elevated biliary enzymes and IgM levels; tests were positive for antimitochondrial antibody and antiacetylcholine antibody. Liver histology revealed chronic non-suppurative destructive cholangitis and led to a diagnosis of primary biliary cirrhosis. The tensilon test was positive. Electromyography with repetitive motor nerve stimulation revealed a neuromuscular junction defect; i.e., the primary characteristic of myasthenia gravis. The patient was diagnosed with myasthenia gravis. Although the development of myasthenia gravis has previously been reported in patients with primary biliary cirrhosis during D-penicillamine administration, this is a very rare case of the coexistence of both diseases before such treatment.

Endoscopic injection sclerotherapy for esophagogastric variceal bleeding in children with biliary atresia

BACKGROUND/AIMS

To determine the safety and effectiveness of endoscopic injection sclerotherapy (EIS) for children with biliary atresia.

METHODOLOGY

Subjects were 7 patients with biliary atresia with esophagogastric varices and variceal bleeding. Intravariceal injection using 5% ethanolamine oleate was performed under fluoroscopy until varices were eradicated.

RESULTS

Endoscopic examination revealed that bleeding occurred in the junctional gastric varices in most of the cases. The mean number of EIS sessions required for obliteration of the varices was 2.3. In the observation period (mean: 21 months), recurrent esophagogastric varices occurred in 2 patients. One had variceal bleeding that was treated successfully by additional EIS. There were no severe complications associated with EIS.

CONCLUSIONS

EIS under fluoroscopy was safe and effective for variceal bleeding in children with biliary atresia.

Standards for selecting percutaneous ethanol injection therapy or percutaneous microwave coagulation therapy for solitary small hepatocellular carcinoma: consideration of local recurrence

OBJECTIVE

Percutaneous ethanol injection therapy (PEIT) and percutaneous microwave coagulation therapy (PMCT) are effective treatments for small hepatocellular carcinoma (HCC). There are no clear standards, however, for the selection of PEIT or PMCT. We determined standards based on local recurrence.

METHODS

The subjects were 88 patients with solitary HCC measuring < or = 30 mm in diameter, who were treated by PEIT (n = 45) or PMCT (n = 43) and judged to be cured using computerized tomography (CT) with contrast medium after treatment. Patient characteristics, including age, gender, viral markers, Child-Pugh classification, tumor size, tumor cell differentiation, and serum alpha-fetoprotein (AFP) concentration we analyzed, and the factors influencing the local recurrence in the PEIT and PMCT groups were determined, using univariate and multivariate analysis.

RESULTS

Univariate analysis indicated that tumor cell differentiation and serum AFP concentration influenced local recurrence in the PEIT group, and tumor size did so in the PMCT group. Multivariate analysis revealed that tumor cell differentiation influenced local recurrence in the PEIT group, and tumor size did so in the PMCT group. PEIT was effective for treating well-differentiated HCC, and PMCT was effective for treating HCC measuring < or = 15 mm in diameter. PMCT was superior to PEIT for treating patients with HCC measuring < or = 15 mm in diameter. In such cases with well-differentiated HCC, PEIT was as effective as PMCT.

CONCLUSIONS

The selection of PEIT or PMCT to treat patients with HCC should be based on tumor size and cell differentiation.

Limitations of imaging diagnosis for small hepatocellular carcinoma: comparison with histological findings

BACKGROUND AND AIMS

The purpose of this study was to clarify the value and limitation of imaging modalities for diagnosing small hepatocellular carcinoma (HCC).

METHODS

Nodules (n = 207) with diameters of 20 mm or less detected by periodic ultrasonography and computed tomography in 139 patients with chronic liver disease were investigated with digital subtraction angiography (DSA) and magnetic resonance imaging (MRI). These findings were compared with histological findings.

RESULTS

Histological diagnoses were adenomatous hyperplasia (AH, n = 27), well-differentiated HCC (n = 99), moderately differentiated HCC (n = 79) and poorly differentiated HCC (n = 2). We compared two groups: group A (n = 62), nodules of 10 mm diameters or less; and group B (n = 145), nodules 11-20 mm. Adenomatous hyperplasia accounted for approximately 30% of group A, but was difficult to diagnose with imaging modalities alone. We diagnosed those nodules showing hypervascular staining on DSA or hyperintensity on MRI T2-weighted images as HCC. Imaging alone was sufficient to diagnose HCC in 58% of the well-differentiated nodules and 87% of the moderately and poorly differentiated nodules (P < 0.01). It was possible to diagnose HCC by imaging alone in 60% of all nodules or 45% of group A and 68% of group B (A vs B, P < 0.005).

CONCLUSIONS

With decreasing differentiation and increasing diameter of nodules, the use of imaging modalities to diagnose HCC improved. Tumour biopsy was required to diagnose 55% of the cases in group A and 32% of the cases in group B.

Differential inhibition of epidermal growth factor signaling pathways in rat hepatocytes by long-term ethanol treatment

BACKGROUND & AIMS

Long-term ethanol intake suppresses liver regeneration in vivo and ethanol interferes with epidermal growth factor (EGF)-induced DNA synthesis in vitro. Therefore, the effects of long-term ethanol treatment on EGF-activated signaling reactions in rat hepatocytes were investigated.

METHODS

Hepatocytes from long-term ethanol-fed rats and pair-fed controls were stimulated with EGF (0.5-20 nmol/L) for 15-120 seconds. Tyrosine phosphorylation of EGF receptor (EGFR), Shc, and phospholipase-C gamma1 (PLC gamma), and growth factor receptor binding protein 2 (Grb2) coprecipitation with EGFR and Shc were analyzed by Western blotting.

RESULTS

EGFR autophosphorylation was suppressed at all EGF concentrations in ethanol-fed cells compared with pair-fed cells, without significant differences in total EGFR protein or EGFR tyrosine kinase activity detected in cell lysates, suggesting that intracellular factors suppressed EGFR function. EGF-induced PLC gamma tyrosine phosphorylation and inositol 1,4,5-trisphosphate (InsP3) formation were suppressed, but cytosolic [Ca2+]c elevation was little affected, indicating enhanced InsP3-mediated intracellular Ca2+ release in ethanol-fed cells. Grb2 binding to EGFR was suppressed, but EGF-induced Shc tyrosine phosphorylation and Grb2 association with Shc were not significantly decreased.

CONCLUSIONS

Long-term ethanol feeding suppressed EGF-induced receptor autophosphorylation in rat hepatocytes with differential inhibition of downstream signaling processes mediated by PLC gamma, Shc, and Grb2. Altered patterns of downstream signals emanating from EGFR may contribute to deficient liver regeneration in chronic alcoholism.

Inhibitory effect of ethanol on hepatocyte growth factor-induced DNA synthesis and Ca2+ mobilization in rat hepatocytes

Hepatocyte growth factor (HGF) is the most potent mitogen identified for hepatocytes and is thought to be an important growth factor in the regulation of liver regeneration. Its effects are mediated through a tyrosine kinase receptor, the product of c-met proto-oncogene. One of the downstream signaling processes activated by HGF is phospholipase C-gamma. HGF stimulation of liver cells causes formation of inositol 1,4,5-triphosphate, which releases Ca2+ from intracellular Ca2+ ([Ca2+]i) stores, and causes elevation of cytosolic Ca2+ levels. It is known that liver regeneration is inhibited by both acute and chronic ethanol (EtOH) treatment. We investigated the effect of EtOH on HGF-induced DNA synthesis and mobilization of [Ca2+]i in rat hepatocytes in primary culture. DNA synthesis was monitored by [3H]thymidine incorporation in primary cultures of hepatocytes 42 hr after stimulation with HGF. HGF concentration required for maximum DNA synthesis was 0.3 to 1 ng/ml, and DNA synthesis was inhibited by 100 mM EtOH at HGF concentrations in the range of 0.1 to 5 ng/ml. This inhibition was strongest (45 to 47% inhibition) at a low concentration of HGF (0.1 to 0.3 ng/ml) and decreased at an HGF concentration > 1 ng/ml. HGF-induced changes in [Ca2+]i were measured in single fura 2-loaded hepatocytes by fluorescence imaging techniques. The Ca2+ response induced by HGF (0.3 to 5 ng/ml) was inhibited by EtOH, with an EC50 of approximately 50 mM. Analysis of Ca2+ response patterns in individual cells indicated that EtOH suppressed the number of responsive cells and made Ca2+ responses more transient, but did not affect peak [Ca2+]i elevation; thus suggesting an inhibition at the level of phospholipase C-gamma-activation. These data indicate that inhibition by EtOH of the response of liver cells to HGF may contribute to the inhibitory effect of EtOH on liver regeneration.

Interaction of protein phosphatases and ethanol on phospholipase C-mediated intracellular signal transduction processes in rat hepatocytes: role of protein kinase A

Phospholipase C (PLC)-mediated signal transduction processes in rat hepatocytes are subject to modulation by protein phosphatases (PPases) and protein kinases, including protein kinase A (PKA) and protein kinase C. Ethanol (EtOH) stimulates PLC activity in liver cells in the absence of hormones, and EtOH pretreatment inhibits the subsequent stimulation of PLC by hormonal stimuli. There is evidence that protein kinase activities are involved in these actions of EtOH. We investigated the effects of okadaic acid (OKA), a PPase inhibitor, and 8-(4-chlorophenylthio)adenosine 3':5'-cyclic monophosphate (cpt-cAMP), a cell permeant cAMP analog that activates PKA, on EtOH-induced PLC activation. In addition, we studied the combined effects of cpt-cAMP and EtOH/OKA on vasopressin-induced PLC activation. PLC activation (cytosolic Ca2+ mobilization and inositol trisphosphate accumulation) induced by EtOH and vasopressin was inhibited by treatment with OKA, and was potentiated by cpt-cAMP. OKA treatment prevented the effect of cpt-cAMP. Pretreatment with EtOH caused inhibition of vasopressin-induced PLC activation. EtOH also decreased the enhancing effect of cpt-cAMP on the responses to vasopressin. The susceptibility to enhancement by cpt-cAMP plotted as a function of the initial rate of vasopressin-induced Ca2+ mobilization in EtOH-treated cells was similar to the pattern observed in OKA-treated cells. These data suggest that interactions of OKA and PKA on EtOH-induced PLC activation occurred at the level of G-protein, and indicate that EtOH may act as an inhibitory agent of PPase.

Effect of glutathione on inositol 1,4,5-triphosphate-induced Ca2+ release in permeabilized hepatocytes from control and chronic ethanol-fed rats

The effect of oxidized and reduced glutathione on inositol 1,4,5-trisphosphate (InsP3)-induced Ca2+ release from endoplasmic reticular Ca2+ stores was studied in digitonin-permeabilized hepatocytes from chronically ethanol-fed rats and pair-fed control animals. The fractional Ca2+ release induced by a subsaturating concentration of InsP3 was significantly enhanced in cells from ethanol-fed rats in the absence of a change in maximal InsP3-releasable Ca2+ pool size, and this difference was not affected by preincubation with reduced glutathione. Incubation with oxidized glutathione (1 mM) increased the efficacy of Ca2+ release by subsaturating concentrations of InsP3 in both control preparations and in cells from ethanol-fed rats. The shift in the InsP3 dose-response curve was not significantly different between the two preparations. These findings suggest that the enhanced efficacy of InsP3-induced Ca2+ release in hepatocytes from ethanol-fed rats is not caused by the oxidation of protein-bound thiol groups on the InsP3 receptor.

Assessment of T1 time course changes and tissue-blood ratios after Gd-DTPA administration in brain tumors

Sequential T1 changes in brain tumor tissue after Gd-DTPA administration were investigated in 10 patients, including 4 meningiomas, 2 gliomas, 3 metastatic cerebral tumors and 1 brain abscess. T1 values were measured serially for 60 minutes following Gd-DTPA injection using a magnetic focusing technique. In vitro T1 of the whole blood samples was also comparatively examined. Time processes in the tissue-blood ratio (TBR) were calculated from two-point relaxation rates at 5 and 30 minutes. The obtained ratios of TBR were ranged from 1.0 to 3.0, probably depending on histological types of brain tumor (the value of 1.0 to 1.5 for meningioma and 1.5 to 3.0 for glioma and metastatic tumor). No significant changes in the T1 value were observed in the examined normal tissue and peritumoral edema. These results indicate that Gd-DTPA plays an important role not only as an image enhancer for tumor tissue but also as an indicator for estimating the blood-brain barrier function.

Transfer index of MR relaxation enhancer: a quantitative evaluation of MR contrast enhancement

To clarify the effects of Gd-DTPA on biological water, we examined the effects of the compound on spin-lattice relaxation rate with various concentrations of gelatin solutions. The results indicate that the effects of relaxation rate of Gd-DTPA in biological water fundamentally correspond to those in aqueous solution. To evaluate the distribution of Gd-DTPA in tissues, we introduced a transfer index that represents the product of tissue-blood ratio of Gd-DTPA and the ratio of extracellular volume of a tissue based on the above findings. The index depends neither on dose of the compound nor on Larmor frequency. The clinical significance of the index was studied in patients with brain tumors. The indexes varied from 0.038 to 0.51, depending on the biological characteristics of the tumors. The transfer index may be used in the quantitative evaluation of MR relaxation enhancement, which may be applied to monitoring therapeutic efficacy and to estimating tissue perfusion.

[Evaluation of peritumoral edema by proton T1 values with special remarks on time courses following intracranial surgery]

Proton NMR is said to be sensitive to change in tissue water content. Much more attention has been paid to clinical NMR technique for evaluating pathophysiological states including intracranial edema dynamics. This paper describes the follow up data in NMR imaging and spin-lattice relaxation time (T1) measurement in peritumoral brain tissues. Special attention was directed to the time course of focal T1 values before and after surgery. Twenty-one patients with brain tumor, including 6 meningiomas, 7 gliomas and 8 metastatic tumors, were subjected to the present studies in the term from March 1983 to September 1985. Age distribution of this series ranged from 39 to 74 years (average: 58.2). Fonar QED 80-alpha system was applied for NMR examinations of dual modes (static magnetic field: 433 gauss), i.e. image display by steady state free precession (SSFP) and in vivo T1 measurement by field focussing technique. Standard T1 values for healthy brain were 290 +/- 41 ms and 230 +/- 34 ms (mean +/- SD) in cerebral gray and white matter, respectively. Both T1 values in tumors and in peritumoral tissues before craniotomy were obviously prolonged as compared to standard T1 of corresponding site. However, it remained difficult to discriminate statistically these histological differences by preoperative T1 values. Time course of peritumoral T1 was characteristic in accordance with the sorts of brain tumor. T1 values in the brain parenchyma around meningioma were shortened after operation in the earlier stage up to 1 month, showing relatively rapid normalization in T1.(ABSTRACT TRUNCATED AT 250 WORDS)

Spin-lattice relaxation times of bound water--its determination and implications for tissue discrimination

Measurements were made of T1 of bound water (T1b) and bound water fraction (alpha) for gelatin solutions and human tissues (sera, brain tumor, cerebral white matter). Bound water fraction in each sample was measured by means of thermal analysis (differential scanning calorimetry: DSC). T1 values were measured by FONAR QED 80-alpha. T1b values were calculated by an equation derived from the fast-exchange two-state model. In the study of gelatin solutions, the relationship between T1 and water content differed depending on the sort of solutions. This was considered to be due to differences in T1b values. In each biological tissue the values of T1b and alpha had different distributions. These results indicate that values of T1b and alpha for biological tissues may be altered in correspondence to the changes in pathophysiological states in those tissues.

[Time course of NMR images and T1 values associated with hypertensive intracerebral hematoma]

The present study describes time courses in tissue T1 values, as well as in NMR imagings, associated with hypertensive intracerebral hematoma (ICH). Non-operative 21 cases of ICH were examined by FONAR QED 80-alpha NMR system, which possessed dual modes of image display and focal T1 measurement (static magnetic field: 433 gauss). As the first step of examination SSFP images are displayed and then, at the regions of interest, absolute values of T1 are measured by field focusing technique. The extent of ICH was revealed as high density zone in NMR imaging, occasionally represented much wider extent of high density area than the finding on X-ray CT. Prolonged T1 values were obtained from such high density zone. This wide-spread high density area was regarded to reflect the spread of perifocal brain edema. T1 value of the hematoma itself was rather shortened in its initial phase within 2 weeks, thereafter followed by prolongation in the time lapse. This seemed to reflect the alterations in the properties of hematoma such as clot formation in earlier phase and resolution in later phase. On the contrary, T1 in the brain tissue surrounded to hematoma was apparently prolonged in the early phase within 2 weeks, representing the maximal values of 312 msec around 2 to 4 weeks after the onset, and then gradually normalized in the period over 1 month. This alteration in tissue T1 likely represents the processes of edema formation and its regression in perifocal zone. T1 values measured in perifocal region might be available for the evaluation of edema state in association with cerebrovascular accident.

[Hemodilutional therapy in raised intracranial pressure; observations in a case of cerebral infarction associated with polycythemia vera]

A 36-year-old man presented with sudden onset of hemorrhagic cerebral infarction in association with polycythemia vera. On admission this patient manifested semicomatous state and left hemiplegia which were gradually progressed. X ray CT demonstrated a severe hemorrhagic infarction in right MCA territory accompanying marked shift of midline structures. Cerebral angiograms represented occlusion of right MCA showing floating emboli in the internal carotid. Hematocrit value was found to be high as 61.2 per cent. Elevated ICP levels were noted by means of epidural pressure monitoring. Deterioration of patient status was considered to be based on impairment of cerebral circulation due to hemostasis by elevated blood viscosity. In addition to administration of mannitol solution, intermittent exsanguinations, 1000 ml in total amount, were performed and hematocrit levels were corrected by hemodilution. Consciousness level was remarkably improved in accordance with reduction of ICP, which well corresponded to values of hematocrit. Level of ICP and tissue perfusion are convinced to be strongly affected by hemorheological factor in the state of raised ICP.