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Biomedical subjects

J Hamada

Publications and source records attributed to J Hamada.

At least 127 records · Page 7Linked to original sources
PubMed1990

Age-related decrease of pulmonary metastasis of rat mammary carcinoma by activated natural resistance.

We found that the number of pulmonary metastatic foci of spontaneously developed rat mammary carcinoma (SST-2), when transplanted subcutaneously in spontaneously hypertensive (SH) rats, decreased with aging. In the SST-2-bearing SH rats, it was observed that T cell functions progressively declined while activities of macrophages and natural killer cells were non-specifically activated by increasing age. To examine the mechanisms of the age-related decrease of pulmonary metastasis in SH rats, we treated the SST-2-bearing rats with anti-(asialo-GM1) antibody and/or carrageenan, which are known to suppress the functions of macrophages and natural killer cells, or with poly(I).poly(C), which is a stimulator to natural killer cells. The anti-(asialo-GM1) treatment significantly increased the number of pulmonary metastatic foci in both young and old SH rats, while poly(I).poly(C) significantly decreased the lung nodules in the old SH rats. These result suggest that the decrease of pulmonary metastasis in the SH rats with aging may be closely correlated with non-specifically activated natural killer cells and macrophages, though it should be also considered that non-immunological tumor-host interactions may be involved in the differences between the young and the old SH rats.

Aging↗
PubMed1990

Immunological regression of metastatic cancer in the liver as a result of "in vivo xenogenization".

We attempted to induce the regression of liver metastatic tumor cells in vivo by the administration to rats of Friend leukemia virus (FV) (in vivo xenogenization). The virus which was used in this experiment, FV, is highly immunogenic and does not normally cause disease in an adult rat. At first, we induced a FV viremia in tumor bearing rats in order to deliver the virus to the site of the tumor cells. FV viremia was induced by injecting 60 mg/kg cyclophosphamide (CY) i.v. after the administration of FV, and by transferring syngeneic bone marrow cells so that FV would be able to infect them and then replicate. In order that the tumor cells which were infected with virus should regress, it was necessary to break down their tolerance to FV antigens. As adoptive immunotherapy we therefore, transferred syngeneic spleen cells from rats which had been immunized with FV to tumor bearing rats. The result of this experiment was that these tumor bearing rats infected with FV which had received either normal syngeneic spleen cells or no spleen cells as controls died from liver metastasis (8 out of 9 rats (89%) and 15 out of 17 (88%) respectively). On the other hand, only 4 out of the 15 (27%) tumor bearing rats which were infected with FV and which received FV-immune spleen cells died from liver metastasis. These sets of data indicate that the in vivo xenogenization of tumor cells are indeed able to induce the regression of metastatic tumor cells.

Animals↗
PubMed1990

Correlation between the presence of microvilli and the growth or metastatic potential of tumor cells.

We used an electron microscope to examine microvilli which appear on the surfaces of various tumor cells with high or low growth potential and/or metastatic ability. The results show that a greater number of microvilli appeared on the surfaces of tumor cells (QRpP and ERpP) which possess high growth potential than on tumor cells (QR and ER) with low growth potential. We also observed that microvilli were more abundant on the surface of highly metastatic clone cells, i.e. c-SST-2 (cl-2), mouse B16 melanoma (F-10) and human colon carcinoma (KM12SM) than on weakly metastatic clone cells, c-SST-2 (cl-4-2), B16 (F-1) and (KM12C). At the same time, more microvilli were observed on the surface of B16 BL6 cells, which were obtained from the metastatic site of the B16 F10 cells, than on the surface of the parent B16 F10 cells. Immunoelectron microscopy revealed that the c-neu oncogene product, which is closely related to an epidermal growth factor receptor, was positively stained in the microvilli of tumor cells (ERpP) with high growth potential and high metastatic ability, whereas the tumor cells (ER) with low growth potential and weak metastatic ability were not stained. These findings suggest that the increased presence of microvilli correlates closely with the growth potential and metastatic ability of tumor cells.

Animals↗
PubMed1990

[Rapid resolution of acute subdural hematoma. Report of two cases].

The authors report two cases of rapid resolution of acute subdural hematoma. Case 1, a 78-year-old male, sustained head trauma and became unconscious for a few minutes, but on arrival he was alert and neurological examination was normal. A computed tomography (CT) scan taken 5 hours after the injury showed a high-dense subdural hematoma partly containing low-density area over the right cerebral hemisphere. He was conservatively treated. A CT scan taken 33 hours after the injury disclosed diminution of the hematoma and appearance of a thin high-density layer in the subdural space adjacent to the tentorium. The high-density layer disappeared on a CT scan taken 7 days after the injury. Case 2, an 84-year-old female, struck her head in the occipital region. On arrival she was drowsy but otherwise had no neurological abnormality. A CT scan taken 1 hour after the injury demonstrated a high-dense subdural hematoma partly containing low-density area over the right cerebral hemisphere. She was conservatively managed and became asymptomatic. A CT scan taken 14 hours after the injury disclosed complete resolution of the hematoma and appearance of a thin high-density layer in the subdural space adjacent to the falx and the tentorium. This high-density layer also completely disappeared on a CT scan taken 14 days after the injury. It was suggested that a mechanism of rapid resolution of the acute subdural hematoma was attributable to washing-out by cerebrospinal fluid.

Acute Disease↗
PubMed1990

[Some differences between the visual and auditory memories in the short-term memory].

In order to clarify the differences between the visual and the auditory memories and the interference effect between them, a paired presentation method was developed. In this method, the subject under the experimental condition memorized two independent sequences of random digits, which were presented simultaneously digit by digit, the digits of the one sequence being presented visually and the digits of the other auditorily. After the presentation, subjects were asked to recall first either the visual or the auditory digit sequence, and then the other sequence. The subject under the control condition, on the other hand, memorized one sequence of random digits which were presented either visually or auditorily, and after recalling them memorized another sequence of random digits presented in the other modality. The results can be summarized as follows. (1) Under the experimental as well as under the control conditions, the recency effect appeared in the auditory memory task, but it did not in the visual memory task. (2) The performance for visual by presented digits under the experimental condition was lower than that under the control condition, whereas the performance for auditorily presented digits under the former was equal to that under the latter. The results presented might suggest that: (1) there are independent visual and auditory memories in the short-term memory; and (2) the memorizing of the auditory materials interferes with the memorizing of the visual one, but the latter does not interfere with the former.

Adult↗
PubMed1990

[Aneurysm arising from the cortical branch of the superior cerebellar artery: case report].

We reported a case of a 64-year-old man who presented a subarachnoid hemorrhage due to rupture of an aneurysm arising from the cortical branch of the superior cerebellar artery (SCA) at the junction of the superior vermian branch and the hemispheric branch. Eight days after the rupture, neck clipping of the aneurysm was performed successfully using the occipital transtentorial approach in a prone position, and the patient's postoperative course was uneventful. This rare case of aneurysm arising from the cortical branch of SCA was discussed with a review of literature.

Arteries↗
PubMed1990

Rapidly destructive coxarthrosis--a report of a patient with "strip-mining" and "interior crumbling" of bone architecture.

The pathomechanism of rapidly destructive coxarthrosis has not been clarified. Interesting findings were obtained in specimen from a 64-year-old male patient, i.e., the break-down (crumbling) of the internal structure of osteonal bone and superficial strip-mining of the femoral head. The detritic fragments and hydroxyapatite crystals were mainly deposited in the pocket of the joint capsule and some of them were embedded beneath the synovial membrane. We conjecture that apatite-associated destructive arthritis and/or detritic synovitis might accelerate the progression of rapidly destructive coxarthrosis.

Cartilage, Articular↗
PubMed1989

Growth-associated shedding of a tumor antigen (CE7) detected by a monoclonal antibody.

A monoclonal antibody was developed against an antigen, termed CE7, which was highly expressed on the surface of rat fibrosarcoma KMT-17 cells (clone A3) cultured in low serum medium (A3-1% FCS). The CE7 antigen was not detectable on A3 cells cultured in ordinary high serum medium (A3-10% FCS), on in vivo passaged A3 cells, or on parental in vivo KMT-17 cell line. However, immunoelectron microscopy and Western blot analyses indicated that CE7 antigen was produced by these tumor cells in all circumstances but was shed from their surfaces in vesicular form into the surrounding tissue culture medium or ascites, unless low serum concentration prevailed and disappeared from their cell surfaces. We have previously reported that the immunogenicity of A3 cells was increased when the serum concentration was lowered from 10% to 1% and the phenomenon paralleled the CE7 antigen expression on the A3 cells. These results suggest that the CE7 antigen could be a tumor-associated rejection antigen and that the expression of the CE7 antigen on A3-1% FCS cells (which is shed by high serum culture or in vivo transplantation and disappears from the cell surface) may play a role in immunological responses against the tumor cells.

Animals↗
PubMed1989

Sweating function and retinal vasomotor reactivity in migraine.

Sweating function and retinal arterial reactivity in patients with migraine were examined during headache-free intervals. The sweat glands were stimulated by intradermal injection of pilocarpine hydrochloride, and molds of sweat droplets were obtained using Silastic. The number of droplets in classic migraine was significantly lower than that in the controls. The retinal arterial response to changes in perfusion pressure was measured by means of a fundus camera. The retinal vasomotor index (-change in retinal arterial diameter (%)/change in effective MABP (mmHg)) was significantly lower in classic and in common migraine than in controls. The above results suggest that sweating function and retinal arterial reactivity are impaired in patients with migraine and that the impairment may play an important role in the pathophysiology of migraine attacks.

Adolescent↗
PubMed1989

[The usefulness of lumbar epidural pressure as an index of intracranial pressure].

The reliability of lumbar intraspinal epidural pressure (ISEDP) as an index of intracranial pressure was investigated in seven patients with high intracranial pressure following neurosurgery. ISEDP and intracranial epidural pressure (ICEDP) were measured simultaneously, the latter by the conventional method. ISEDP was measured with a Gaeltec catheter-tip pressure transducer placed percutaneously in the lumbar epidural space via Touhy's needle. In five of seven patients, the ISEDP value was consistently 70 to 100% of the ICEDP value. In all patients, ISEDP always fluctuated in parallel with ICEDP, and the time courses of both were quite similar in response not only to normal cardiac pulsation but also to various manipulations, such as neck compression, coughing, breath holding, mannitol administration, and compression at the cranial defect. In one patient with communicating hydrocephalus following subarachnoid hemorrhage, the relationship between ISEDP and cerebrospinal fluid (CSF) pressure was studied. Upon gradual withdrawal of CSF, ISEDP decreased in parallel with CSF pressure until the latter reached 8 mmHg. Below 8 mmHg CSF pressure, ISEDP did not correlate with CSF pressure. This phenomenon was attributed to slackness of the dural sac due to lowering of CSF pressure, which severed contact between the spinal dural theca and the sensor. Although the discrepancy between ISEDP and ICEDP was prominent in some patients, especially those with low intracranial pressure or blockage of the subarachnoid space, in this study ISEDP reliably reflected ICEDP. The results suggest that ISEDP measurement is useful in monitoring intracranial pressure in patients with increased intracranial pressure. Also, the procedure is simple and relatively noninvasive.

Adult↗
PubMed1989

[Timing of UFT administration combined with surgical operation in pulmonary metastasis of rat mammary carcinoma].

We investigated the effective timing of UFT administration combined with surgical operation for inhibiting pulmonary metastasis of spontaneously developed mammary carcinoma (SST-2) which produces 100% pulmonary metastasis in syngeneic rats after s.c. transplantation. Rats (5 rats per group) were inoculated s.c. with 1 X 10(6) SST-2 cells and administered orally with UFT (15, 30 and 60 mg/kg/day) starting 21 days after the tumor inoculation for 2 weeks. UFT at the dose of 30 mg/kg/day was found to be most effective in inhibiting pulmonary metastasis in SHR rats without any noticeable side effects. The rats inoculated s.c. with 5 X 10(4) SST-2 cells were divided into 3 groups: The 1st group was given oral administration of UFT (30 mg/kg/day) starting 7 days before surgical excision of the primary tumor for 2 weeks; 2nd group was treated with UFT starting one day after surgical operation for 2 weeks; and 3rd group was treated with UFT starting 7 days after surgical operation for 2 weeks. The number of lung colonies and survival time were compared among these 3 groups. The results clearly showed that combination of UFT and surgical operation was most effective on the 1st group when compared with the other two groups. UFT therapy, therefore, should be started prior to surgical operation for inhibiting cancer metastasis.

Animals↗
PubMed1989

[Experimental approach to the investigation of tumor progression].

We investigated the effects of host inflammatory cells on the progression of QR (C57BL/6 mouse) and ER (SHR rat) regressor tumor cells which spontaneously regress in normal syngeneic hosts. We noted an enhanced tumorigenicity of regressor tumor cells after s.c. implantation with attachment to plastic plate, a situation which induces inflammation in normal hosts accompanied by the development of tumors as compared to normal mice injected with regressor tumor cells in suspension in PBS- which spontaneously regressed. We also observed enhanced tumorigenicity of regressor tumor cells injected into the site of the plastic plate which had been previously implanted into the normal host. Regarding these phenomena, we suggest that tumor progression may be induced by host induced inflammatory cells or their products. We also found enhanced tumor progression of QR regressor tumor cells after co-inoculation with inflammatory cells produced by the implantation of hemostatic spongel into the peritoneal cavity of mice. The mechanisms involved in the progression of regressor tumor cells by co-existence with inflammatory cells are thought to be associated with the production of oxygen radicals, tumor cell chemotactic factors, soft agar colony promoting factors and PGE2.

Animals↗
PubMed1988

Metastatic capacity and intercellular communication between normal cells and metastatic cell clones derived from a rat mammary carcinoma.

Three highly metastatic clones and two weakly metastatic clones were obtained from a spontaneously arising mammary carcinoma in an SHR rat. The difference in their capacity to generate metastatic ability was recognized when the tumor cells were implanted s.c. but not when they were implanted i.v. This evidence possibly indicates that the difference in the metastatic capacity of these clones is caused by different potential for detachment from the primary site and for intravasation during the various steps of metastasis. There are no differences between highly and weakly metastatic clones with regard to their in vitro growth characteristics (doubling time, saturation density, plating efficiency, etc.), homotypic aggregation, and adhesiveness to plastic matrices and fibroblast monolayers. Therefore, we used a dye transfer method to examine the relationship between the metastatic capacity of tumor cells and the capacity of tumor cells to make junctional communication with normal fibroblasts. We found that the incidence of intercellular communication between weakly metastatic clone cells and fibroblasts (derived from normal s.c. tissues and tumor tissues) was significantly higher than that between highly metastatic clone cells and fibroblasts. These results suggest that junctional communication between tumor cells and normal fibroblasts may play a part in the early stage of cancer metastasis.

Animals↗
PubMed1988

Modification of regression of virally xenogenized tumor cells by cyclophosphamide and busulfan.

Rat fibrosarcoma cells infected with Friend leukemia virus (FV-KMT-17) grow for a short time and then regress spontaneously in syngeneic hosts. This regression mechanism was examined by analyzing the immunomodulating action of the antitumor drugs busulfan (BU) and cyclophosphamide (CY). In preliminary experiments, the optimum dosages of BU and CY for the enhancement of DTH responses to SRBC were 10 mg/kg and 40 mg/kg respectively. Treatment of rats with BU (10 mg/kg) on day 5 induced the regression of KMT-17 cells, while in contrast, the same drug delayed the spontaneous regression of FV-KMT-17 cells. Pretreatment with CY (40 mg/kg) on day 5 did not affect the growth of KMT-17 or FV-KMT-17 cells. After the same treatment schedule, BU inhibited humoral antibody formation against SRBC and against virus-associated antigen (VAA), NK cell activity, and ADCC effector cell activity. On the other hand, CY did not affect the activities of NK cells or ADCC effector cells, although it significantly augmented the DTH responses to SRBC and the production of antibody to VAA but had no effect on production of antibodies to SRBC. These results suggest that NK cells and ADCC may play an important role in the initial stage of the spontaneous regression of FV-KMT-17 cells.

Animals↗
PubMed1988

Depression of T cell-mediated immunity and enhancement of autoantibody production by natural infection with microorganisms in spontaneously hypertensive rats (SHR).

We studied the effects of breeding conditions on the development of immunological abnormalities in spontaneously hypertensive rats (SHR) with congenital T cell depression. The depression of T cell functions, the production of natural thymocytotoxic autoantibody (NTA), and the development of polyarteritis nodosa were more evident in SHR reared under a conventional (CV) environment than in specific-pathogen-free (SPF) SHR bred in a semi-barrier system. Enhancement of these immunologic abnormalities was also observed by the conventionalization of SPF-SHR. A high frequency of antibodies to mouse hepatitis virus (MHV), Sendai virus, and Mycoplasma pulmonis was detected in CV rat sera, whereas no antibodies were detected in SPF-SHR. The experimental infection of Sendai virus induced the enhancement of T cell depression and of NTA production in SPF-SHR. We interpret these results to mean that the natural infection of microorganisms causes an acceleration of immunologic abnormalities in SHR reared in a CV environment.

Animals↗
PubMed1988

[Effects of symmetry groups on complexity and goodness in visual pattern].

Two experiments were performed to investigate stimulus determinants of pattern complexity and pattern goodness. Two hundred and ninety-six undergraduates rated complexity and goodness of two-dimensional patterns, which consisted of solid and/or open circles. The patterns were invariant under transformations of reflection or rotation, and they formed cyclic groups or dihedral ones. The results were summarized as follows. (1) Goodness of patterns increased with the order of cyclic and dihedral groups with different weights. (2) Complexity of patterns having line-segments decreased with the order of cyclic and dihedral groups with equal weights, whereas that of patterns having no line-segments was medium regardless of the order. (3) Simplicity and goodness of patterns with a vertical axis of reflection were higher than those with the other orientation axes. (4) Patterns consisting of solid circles were rated more complex than those of open ones. (5) Complexity increased as a positively accelerated function of the number of circles, whereas goodness increased as a negatively accelerated function. It was concluded that complexity and goodness were determined by compound factors, which are processed at different stages of human visual system.

Adult↗