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T Tada

Publications and source records attributed to T Tada.

At least 19 recordsLinked to original sources
PubMed1992

Particular types of tumor cells have the capacity to convert transforming growth factor beta from a latent to an active form.

We investigated the capacities of various tumor types to generate an active versus latent form of transforming growth factor beta (TGF-beta) in its culture supernatants (SNs). Tumor cell lines were divided into three types depending on the form and magnitude of TGF-beta detected in their culture SNs: some (2 of 7 lines) generated mostly an active form (Type A); others (4 of 7) generated exclusively a latent form (Type B); and the remaining line (1 of 7) produced only marginal levels of active/latent TGF-beta (Type C). When Type A tumor cells were cultured at lower numbers, cultures failed to generate active TGF-beta. However, the addition of Type B tumor cell culture SNs containing only a latent form of TGF-beta resulted in the generation of the potent activity of active TGF-beta. This capacity was observed for another Type A tumor but not for other types (Type B and Type C). An active form of TGF-beta was detected in culture SNs of Type A tumor cells as early as 3-6 h after the addition of Type B tumor culture SNs. The emergence of an active form of TGF-beta was also observed in cultures of Type A tumor cells, the protein synthesis of which was almost completely inhibited by pretreatment with cycloheximide. Moreover, the Type B tumor SN used for the induction of active TGF-beta activity was found to contain latent TGF-beta with an apparent molecular weight of about 200,000. Type A tumor cells were also capable of generating active TGF-beta by the addition of recombinant TGF-beta of latent form with a small molecular weight (about 60,000), although the generation of active TGF-beta was much weaker after the addition of small latent TGF-beta than after the addition of large latent TGF-beta. Taken collectively, these results indicate that particular types of tumor cells have the capacity to generate an active form of TGF-beta and that such capacity can be attributed to their potential to convert TGF-beta from a latent (mainly large type) to an active form.

Animals↗
PubMed1992

Establishment of stable CD8+ suppressor T cell clones and the analysis of their suppressive function.

Stable CD8+ suppressor T cell (Ts) clones were established by a relatively simple method. Keyhole limpet hemocyanin (KLH)-primed spleen cells from C3H mice were depleted of B cells and CD4+ T cells by panning and cytotoxic treatment, and the resulting CD8+ T cells were periodically stimulated with antigen and irradiated syngeneic spleen cells followed by manifestation in interleukin-2 (IL-2) containing medium. T cell clones with a definite suppressor function were established by limiting dilution. They were defined as classical effector type Ts of CD8+ phenotype as they had constant and definite suppressor functions in antigen-induced T cell proliferation and specific antibody response against T cell-dependent antigens without detectable cytotoxic activity against both antigen presenting cells (APC) and helper T cells (Th). They showed no helper activity for B cells and produced no detectable helper type lymphokines such as IL-2 and IL-4. CD8+ Ts clones were able to inhibit the antigen-induced IL-2 production of normal and cloned T cells. Their suppressive activity was antigen-nonspecific and major histocompatibility complex-unrestricted. CD8+ Ts clones were also able to suppress the proliferative response of Th clones induced by immobilized anti-T cell receptor (TcR) and anti-CD3 mAbs but not the response induced by concanavalin A (ConA) and IL-2. All the CD8+ T cell clones established independently utilized the TcR V beta 8 gene. Syngeneic antigen presenting cells could induce proliferation of these CD8+ clones, which was blocked by anti-CD8 and anti-I-Ak monoclonal antibody (mAb) but not by anti-class I mAbs. The stimulation of CD8+ Ts clones with immobilized anti-CD3 resulted in the release of a suppressor factor(s) that potently inhibited the antigen-induced proliferation of CD4+ Th clones and the in vitro secondary antibody formation.

Animals↗
PubMed1992

[Magnetic resonance (MR) imaging of chordoma and chondroma in the skull base--differential diagnosis by IR sequence].

Differential diagnosis of chordoma and chondroma in the skull base is sometimes difficult. We retrospectively reviewed the MR images of 14 patients with skull base tumors (nine chordomas, four chondromas and one chondrosarcoma). MR imaging was performed with a 0.5 Tesla system (Picker International). Inversion recovery (IR) (2500-2100/600-500/40), T1-weighted spin echo (SE) (800-600/40), and T2-weighted SE (2500-1800/120) images were obtained. On IR images, seven of eight chordomas showed heterogeneous low signal intensity, and one chordoma and all chondromas showed markedly low signal intensity similar to that of CSF. Calcified or ossified portions of the chondromas were demonstrated as areas of moderately low intensity on IR images. Chondrosarcoma showed moderately low intensity similar to that of chordoma. T1-weighted SE images of chordoma and chondroma showed no difference in signal intensity. On T2-weighed SE images, six of nine chordomas and all chondromas showed markedly high signal intensity. Three chordomas and one chondrosarcoma showed moderately high signal intensity. In the diagnosis of skull base tumors, the IR sequence seems to be useful for differentiating chondroma from chordoma.

Adolescent↗
PubMed1992

[Radiosensitizing effect of a 2-nitroimidazole hydroxamate (KIN-804) to murine tumors].

We studied the toxicity, pharmacokinesis and radiosensitizing effect of a newly developed 2-nitroimidazole-1-methylacetohydroxamate (KIN-804) in C3H/He mice bearing SCC-VII tumor. They were compared with misonidazole. LD50/7 of KIN-804 and misonidazole were 3200 and 2000 mg/kg. The concentration of KIN-804 in the brain and sciatic nerve was at a very low level and its clearance from the sciatic nerve was rapid. Enhancement ratios calculated using the growth delay method were 1.50 for KIN-804 and 1.36 for misonidazole respectively when they were administered by intraperitoneal injection with a dose of 100 mg/kg. KIN-804 was considered to be a promising radiosensitizer because it obtained less toxicity and a higher radiosensitizing activity than misonidazole.

Animals↗
PubMed1992

Malignant pilomatricoma. An immunohistochemical study with antihair keratin antibody.

A case is reported of malignant pilomatricoma confirmed by immunohistochemistry using anti-human hair keratin (anti-HHK) antibody prepared by the authors. The tumor occurred in the soft tissue of the inguinal region of an 88-year-old woman, with later invasion of the epidermis. No other possible primary lesion was found at autopsy. Histologically, the tumor was squamous cell carcinoma with nests of tumor cells and shadow cell-like necrotic cells showing central keratinization and focal calcification. Immunohistochemically, the hair keratin was positive in this tumor and in benign pilomatricomas exclusively. All other skin lesions and various squamous cell carcinomas examined were negative for this antigen. The staining patterns of commercial antiepidermal keratin and antiinvolucrin antibodies were significantly different from that of anti-HHK in normal skin and in these lesions. To the authors' knowledge, this is the first case of malignant pilomatricoma tested with anti-HHK staining. Malignant pilomatricoma is generally a low-grade malignant tumor, but it can metastasize and be fatal as it was in this case.

Aged↗
PubMed1992

Early development and X-chromosome inactivation in mouse parthenogenetic embryos.

Early development and X-chromosome inactivation were studied in ethanol-induced mouse parthenogenones. About 24% of oocytes transferred to 0.5-day pseudopregnant recipients successfully implanted. However, only 49%, 20%, and 16% of implanted parthenogenones survived 5, 6, and 7 days later, respectively. Abnormal development was evident in every parthenogenone as early as 5 days after activation with the degenerating polar trophectoderm. These embryos were destined to become either small disorganized embryos or embryonic ectoderm vesicles bounded by the visceral endoderm. Only 2 of 51 representative 6- to 8-day parthenogenones sectioned had morphology of the normal egg cylinder, although growth retardation was evident. Spontaneous LT/Sv parthenogenones shared similar morphological features. In late blastocysts, the frequency of cells with an apparently inactivated X chromosome was lower in parthenogenones than in fertilized embryos. The failure of X-inactivation in the trophectoderm seems to contribute to the defective development of parthenogenones.

Animals↗
PubMed1992

Secretory meningioma associated with numerous meningothelial rosettes.

A case of secretory meningioma with numerous meningothelial rosettes is reported. A 66-year-old man with moyamoya disease gradually developed skull deformity, and underwent surgery for the skull tumor overlying the hemisphere. Histological examination disclosed numerous meningothelial rosettes quite similar to those induced by subarachnoid injection of epinephrine and pseudopsammoma bodies described by Kepes. This may be the first case of meningioma associated with numerous rosette formations.

Aged↗
PubMed1992

Neuroepithelial cyst of the lateral ventricle. Clinical features and treatment.

This report concerns eight patients with noncolloid neuroepithelial cyst of the lateral ventricle, including four surgical and four conservative cases. Of the surgical patients, two had headache, one had orbital pain, and one had seizures. In the conservative group there were no symptoms due to the cysts and no changes in computed tomography scan during follow-up for an average of 1.4 years. Magnetic resonance imaging was performed in five cases and showed a cyst with an intensity similar to cerebrospinal fluid, while a cyst membrane was also detected in three cases. Our findings suggest that (1) the majority of symptomatic neuroepithelial cysts in the lateral ventricle are located in the trigone; (2) the cause of symptoms suggestive of obstruction, such as headache, is an isolated ventricle that demonstrates dilatation of the inferior horn on computed tomography and magnetic resonance imaging; (3) the operative indication is obstructive symptoms; and (4) cyst-peritoneal shunt is an effective procedure.

Adult↗
PubMed1992

Radiosensitizing, toxicological, and pharmacokinetic properties of hydroxamate analogues of nitroimidazoles as bifunctional radiosensitizers/chemical modifiers.

We examined the pharmacokinetics of KIH-802, potassium 2-nitroimidazole-1-acetohydroxamate, using its radioisotope-labelled compound and the acute toxicity in mice. We discovered that the concentration of KIH-802 was very low in the brain and its LD50 was nearly half the value of that of MISO. We also present here new 2-nitroimidazole radiosensitizers/chemical modifiers (KIN-804, 811, 831, 841, 844, 821, 823 and 824) designed to enhance their sensitizing ability intensely by substituting various biologically active groups, such as hydroxamic acids and oximes, with moderate lipophilicity to the aromatic ring, if necessary, through some spacers. The sensitizing effects of all compounds were estimated to be almost equal to or better than that of MISO. The results of their toxicities shows that new hydroxamates KIN-804 and 831 are less toxic than KIH-802 and MISO. Their in vitro enhancement ratios are 2.00 and 1.75, respectively, compared with those of KIH-802, MISO and SR-2508, 1.77, 1.72 and 1.72, respectively, at each dose of 1 mM for EMT6/KU single cell. We concluded that they may be superior radiosensitizers of hydroxamic acid analogues to KIH-802.

Animals↗
PubMed1992

Kinetic study of the transformation from tetrahydrate to monohydrate of a new antiallergic, sodium 5-(4-oxo-phenoxy-4H-quinolizine-3-carboxamide)-tetrazolate.

Two hydrates (tetrahydrate, I, and monohydrate, II) of a new antiallergic, sodium 5-(4-oxo-phenoxy-4H-quinolizine-3-carboxamide)-tetrazolate (FR71021), were prepared and characterized by means of infrared spectrometry, thermal analysis, and power X-ray diffraction spectrometry. While I was confirmed to dehydrate readily resulting in an anhydrate form (noncrystalline form) below its critical relative humidity for dehydration, I was also transformed into II under humid conditions. The transformation kinetics from I to II were investigated under varying temperature and humidity conditions by a powder X-ray diffraction technique. The transformation mechanism followed a zero-order reaction, and the apparent transformation rate constant (k) could be described as a function of water vapor pressure (P), temperature (T), and the interaction orders between water vapor pressure and the samples (s): k = A.exp(-Ea/RT).Ps, where Ea is the activation energy and R is the gas constant.

Biotransformation↗
PubMed1992

Intracranial mycotic aneurysm caused by Aspergillus--case report.

A 75-year-old female with chronic renal failure diagnosed as Wegener's granulomatosis was receiving steroids and immunosuppressive agents when subarachnoid hemorrhage developed. Cerebral angiography showed a fusiform aneurysm arising from an angular branch of the left middle cerebral artery. Hemorrhage occurred and the aneurysm was excised by emergency surgery. Microscopic examination of the aneurysm revealed dense infiltration of hyphae identified as Aspergillus. She died of subsequent hemorrhage. Autopsy showed numerous Aspergillus hyphae in the lung. Fungal mycotic aneurysm should be considered in the differential diagnosis of an immunocompromised patient with subarachnoid hemorrhage.

Aged↗
PubMed1992

WF11605, an antagonist of leukotriene B4 produced by a fungus. II. Structure determination.

The structure of WF11605, a novel tetracyclic triterpene glucoside, was determined to be 1. The plane structure of deacetyl-WF11605 aglycone was elucidated as 2 through the concerted application of a series of 2D NMR techniques. The relative configurations were established by X-ray crystallographic analysis of bis(p-bromobenzoyl) derivative 3 and absolute stereochemistry by CD exciton chirality method.

Chrysenes↗
PubMed1992

[Changes in seizure-triggering threshold and after discharge duration in seizure susceptibility].

Epilepsy is analysed on terms of two different conditions, seizure susceptibility and seizure induction. Reports on detailed changes of seizure-triggering threshold and after discharge duration in seizure susceptibility are few. We examined staged changes of seizure-triggering threshold and after discharge duration in seizure susceptibility in a cat amygdaloid kindling model. Ten crossed adult cats were used. We investigated after discharge threshold (ADT), partial seizure threshold (PST) in stage 4 group (P) and generalized seizure threshold (GST) in stage 6 group (C). At the same time, we examined after discharge duration on electroencephalograph (EEG) in each stage. Seizure-triggering threshold decreases significantly step by step. After discharge duration increases significantly step by step. It is concluded that staged decrease of seizure-triggering threshold and increase of seizure's grade and duration was seen in seizure susceptibility.

Amygdala↗
PubMed1992

Suppression of immune responses by cloned T cells and their products.

We have established a number of IL-2 dependent T cell clones with a definite suppressor function for the antibody response. Our collection included CD4+ helper (Th) and suppressor T cell (CD4+ Ts), and CD8+ cytotoxic (Tc) and suppressor T cell (CD8+ Ts) clones. Ts clones were defined by their suppressive activity on antigen-induced proliferative response and on helper functions of other CD4+ Th clones without detectable cytotoxicity and production of known helper type interleukins. The I-J expression was found to be present on both Th and Ts clones, and was generally associated with the H-2 restriction specificity of TcR of these clones. We have shown that the activated CD4+ Ts cells could inhibit the increase of intracellular Ca2+ of Th clones induced by antigen-pulsed antigen-presenting cells (APC). The identity of MHC restriction-specificities was required for the instant suppression of Ca2+ influx of Th clones, while a longer period of activation of Ts clones was needed to suppress the response of Th clones having different MHC restrictions. A strict selectivity was found in the suppressive activity of Ts clones in that Ts clones could suppress the Ca2+ responses of Th1 or Th2 clones but not of other CD4+ Ts clones. Ts clones could suppress the Ca2+ influx of Th clones induced only by antigen-pulsed APC or anti-TcR antibody but not by Con A or IL-2. Both CD4+ and CD8+ Ts clones released soluble immunosuppressive factors upon stimulation with immobilized anti-CD3 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Postoperative intracranial hemorrhage due to vitamin K deficiency: report of two cases].

Vitamin K deficient hemorrhagic diathesis is well known as a cause of infantile intracranial hemorrhage. Its occurrence, however, as a post-surgical complication is rare and has never been reported previously. Two cases are presented here which illustrate the existence of such a hazard. Case 1. A 73-year-old woman admitted with subarachnoid hemorrhage (WFNS IV) underwent microsurgical exploration of a left internal carotid aneurysm, and neck clipping of the aneurysm was performed. She had an uneventful postoperative course, but her neurological condition deteriorated suddenly on the fifth postoperative day. CT scan revealed a large epidural hematoma. Case 2. A 6-year-old boy was admitted due to the dysfunction of a ventriculo-peritoneal shunt system that had previously been placed for hydrocephalus. This dysfunction was thought to be caused by meningitis. Twelve days after ventricular drainage and antibiotic therapy, sudden intraventricular hemorrhage occurred. In both cases, PT and APTT were markedly prolonged, FDP slightly increased and fibrinogen slightly decreased. SFMC was positive in case 2. After the administration of vitamin K, PT and APTT were immediately normalized. Recent reports emphasize the adverse effect of antibiotics that leads to vitamin K deficient hemorrhagic diathesis, especially, in patients in a cachectic state. In these two cases, such a cachectic condition was not observed. We presume that the cause of vitamin K deficiency would be, along with the administration of antibiotics, a preliminary condition of disseminated intravascular coagulation which is encountered in some neurological disorders including subarachnoid hemorrhage. We conclude that attention should be paid for these pitfalls in perioperative neurosurgical care.

Aged↗