Biomedical subjects

N Ohta

Publications and source records attributed to N Ohta.

At least 19 recordsLinked to original sources

PubMed1992

A histidine protein kinase homologue required for regulation of bacterial cell division and differentiation.

Differentiation in the dimorphic bacterium Caulobacter crescentus results from a sequence of discontinuous, stage-specific events that leads to the production of a stalked cell and a new motile swarmer cell after each asymmetric cell division. As reported previously, pseudoreversion analysis of mutations in the pleiotropic developmental gene pleC identified three cell division genes: divJ, divK, and divL. We show here that one of these genes, divJ, encodes a predicted protein of 596 residues with an extensive hydrophobic N-terminal region and a C-terminal domain containing all of the invariant residues found in the family of bacterial histidine protein kinases. Our results also show that divJ is discontinuously transcribed early in the swarmer cell cycle during a period that coincides with the G1 to S transition. We propose that the DivJ protein is one member of a signal transduction pathway regulating the cell cycle and differentiation in Caulobacter and that protein modification by phosphorylation may play a central role in coupling developmental events to progress through the cell division cycle.

Amino Acid Sequence↗

PubMed1992

C-erbB-2 oncoprotein expression versus internal mammary lymph node metastases as additional prognostic factors in patients with axillary lymph node-positive breast cancer.

The relationship was assessed between c-erbB-2 oncoprotein expression and other prognostic factors in breast cancer, such as axillary and internal mammary node metastases. The value of these indicators was analyzed in estimating prognosis, especially in patients with axillary node-positive breast cancer. These results showed that c-erbB-2 is significantly related to clinical stage and axillary node metastases. A univariate study revealed that disease-free and overall survival were correlated significantly with clinical stage, tumor size, axillary and internal mammary node metastases, and 21N status. Among the patients with axillary node involvement, however, 21N status did not appear to be a significant additional prognostic factor. Internal mammary node metastases were significant. In a multivariate study, only axillary and internal mammary node metastases were significant prognostic factors for either the entire group of patients or those with positive axillary nodes. Therefore, axillary node dissection and biopsy of the internal mammary nodes may provide important prognostic information for patients with breast cancer.

Adult↗

PubMed1992

Papillary thyroid cancer and its surgical management.

The surgical management in papillary thyroid cancer has been highly controversial. In the Department of Surgery (II), Kanazawa University Hospital, the surgical management especially for cervical lymph node metastases has changed since 1973 from a conservative approach to an aggressive one. In order to determine whether an aggressive approach is warranted, a retrospective multivariate analysis was carried out on 106 cases of papillary thyroid cancer. The patients have been followed for 10-28 years. Multivariate analysis was conducted following Cox's model. By this analysis, aggressive management appeared to have no impact on survival or relapse-free survival. However, age, sex, tumor size, and cervical lymphadenopathy were confirmed to be important prognostic factors in survival and/or relapse-free survival.

Adult↗

PubMed1992

Oncological aspect of immediate breast reconstruction in mastectomy patients.

In this study, we compared the relapse-free and overall survival of 83 patients who underwent mastectomy with immediate reconstruction (MIBR) using a musculocutaneous flap with or without silicone implant with those of 153 patients with breast cancer who underwent mastectomy without immediate reconstruction. In univariate analysis, the overall and/or relapse-free survival of reconstructed patients with four or more positive axillary lymph nodes or those with menopausal status were significantly inferior compared with those of nonreconstructed patients. In multivariate analysis, however, the immediate breast reconstruction did not appear to have a significant adverse influence on all patients, and on the subgroups stratified by menopausal status or axillary lymph node metastases. Therefore, it was concluded that MIBR using a musculocutaneous flap did not compromise the survival of patients with breast cancer.

Adult↗

PubMed1992

Transfection and expression of a gene coding for a human melanoma antigen recognized by autologous cytolytic T lymphocytes.

Human melanoma line MZ2-MEL expresses several antigens recognized by autologous cytolytic T lymphocytes (CTL). As a first step towards the cloning of the gene coding for one of these antigens, we tried to obtain transfectants expressing the antigen. The DNA recipient cell was a variant of MZ2-MEL which had been selected with a CTL clone for the loss of antigen E. It was cotransfected with genomic DNA of the original melanoma line and with selective plasmid pSVtkneo beta. Geneticin-resistant transfectants were obtained at a frequency of 2 x 10(-4). These transfectants were then screened for their ability to stimulate the production of tumor necrosis factor by the anti-E CTL clone. One transfectant expressing antigen E was identified among 70,000 drug-resistant transfectants. Its sensitivity to lysis by the anti-E CTL was equal to that of the original melanoma cell line. When this transfectant was submitted to immunoselection with the anti-E CTL clone, the resulting antigen-loss variants were found to have lost several of the transfected pSVtkneo beta sequences. This indicated that the gene coding for the antigen had been integrated in the vicinity of pSVtkneo beta sequences, as expected for cotransfected DNA.

Antigens, Neoplasm↗

PubMed1992

The relationship between lymph node metastases and DNA-ploidy status as prognostic factors in invasive breast cancer.

We evaluated the relationship between the regional lymph node metastases and the DNA ploidy status in 207 patients with invasive breast cancer, as well as their prognostic values in estimating the prognosis of breast cancer. A significantly higher incidence of aneuploidy was found in patients with a large T3 or T4 tumor, a positive axillary lymph node status, more than 4 positive axillary lymph nodes or positive internal mammary lymph nodes. In a univariate study, the overall survival was significantly correlated with tumor size, axillary lymph node status, axillary and internal mammary lymph node metastases, and DNA ploidy status. In the multivariate analysis, however, only axillary and internal mammary lymph node metastases were recognized as important independent prognostic factors on survival. In this series, the DNA ploidy status did not appear to be an independent prognostic factor either in the entire series or in negative axillary node patients, since it was closely correlated with the axillary or internal mammary lymph node metastases, and the axillary node negative patients had an extremely favorable prognosis.

Adult↗

PubMed1992

Effect of temporary pacing on patients with bradycardia in the acute stage following subarachnoid hemorrhage.

In nine cases of bradycardiac arrhythmia of less than 50 bpm that arose during cerebral vasospasm following aneurysmal rupture the patients were treated by temporary pacing. In patients with cerebral vasospasm, in whom autoregulation of the cerebral circulation is impaired, bradycardia aggravates the risk of decreased cerebral blood flow. This study demonstrated that temporary pacing is an effective and safe procedure in maintaining heart rate during vasospasm.

Bradycardia↗

PubMed1992

Cell cycle regulation in bacteria.

Significant progress has been made in the study of ftsZ expression and the topology of FtsZ protein localization in Escherichia coli cells. Exciting results on the identification of new genes required for chromosome resolution and partitioning after the completion of DNA synthesis have also been reported. A recent area of study is asymmetric cell division and its role in differentiation in Bacillus subtilis and Caulobacter crescentus. Biochemical activities of bacterial cell division gene products are also beginning to be addressed.

Bacteria↗

PubMed1992

Wide resection with latissimus dorsi muscle transposition in breast conserving surgery.

In this study we evaluated whether the immediate transposition of the latissimus dorsi muscle (LDM) improves breast appearance and patient satisfaction after quadrantectomy. Twenty-three patients (transposed group) had the transposition of LDM immediately after quadrantectomy, but eight patients (non-transposed group) had quadrantectomy alone. For evaluation, breast size was classified as small (A or B cup) and large (C or D cup). Consequently, the cosmetic result was evaluated as excellent in 73% of the patients with transposed small breasts, but in only 25% of the patients with non-transposed small breasts and by none of the patients with transposed large breasts. On the other hand, all patients with transposed small breasts reported that they are satisfied with their operation, as opposed to 88% of the patients with transposed large breasts and 63% of the patients with transposed large breasts and 63% of the patients with non-transposed small breasts. It was concluded therefore, that the transposition of LDM is useful in correcting post-quadrantectomy breast deformity, especially in patients with small breasts.

Adult↗

PubMed1992

Analysis of antigenic determinants shared by two different allergens recognized by human T cells: house dust mite (Dermatophagoides pteronyssinus) and chironomid midge (Chironomus yoshimatsui).

To analyse the cross-reactivity of T-cell-mediated immunity between Dermatophagoides pteronyssinus (Dp) and Chironomus yoshimatsui (Cy), the most common allergens in Japan, we established antigen-specific human T-cell lines and clones. Some but not all of the Cy-induced T-cell lines showed a significant proliferative response not only to Cy, but also to Dp. No T-cell line responded to other unrelated antigens. When we stimulated the Dp-induced T-cell clones with Cy, 3 of the 40 clones (7.5%) showed a significant proliferation, and 2 of the 3 clones produced interleukin-4 and interferon-gamma, indicating their helper function. Cross-reactivity was diminished significantly after the absorption of Dp antigen in an anti-Cy affinity column. The cross-reactive epitopes were thought to be expressed on the Dp molecule of 45-53 kD. The presence of helper T cells reactive to both allergens suggests a possibility that this cross-reactivity might be involved in part in the high incidence of allergy to the 2 major allergens.

Allergens↗

PubMed1992

The mechanism of photosensitization in photodynamic therapy: chemiluminescence caused by photosensitization of porphyrins in saline containing human serum albumin.

Chemiluminescence (CL) caused by photosensitization of porphyrins in phosphate buffered saline (PBS) solution containing 3% human serum albumin (HSA) was observed for the first time. Irrespective of porphyrins concerned, CL shows a spectrum ranging from 380 to 520 nm with a peak near 450 nm and decays almost single-exponentially with a lifetime of about 15 s. The intensity of CL depends on concentrations of porphyrins and HSA in PBS solution. We have examined a number of porphyrins and observed CL for the compounds with triplet lifetimes longer than 0.1 ms. The appearance and quenching of CL by photosensitization of porphyrin-HSA systems indicate that type II reaction by singlet oxygen occurs significantly in photodynamic therapy resulting in hypoxic regions in environments surrounding the sensitizer.

Humans↗

PubMed1992

[Tsutsugamushi disease found in Haruna District, Gunma Prefecture--evaluations of the clinical features and the outbreak pattern].

From November to December in 1990, 7 cases of tsutsugamushi disease were found first in the southern foot of Mt. Haruna of Gunma Pref., Japan. The present study was conducted to clarify the clinical features and the outbreak pattern of rickettsial infection in this area. All the patients consisting of 6 males and 1 female farmers were admitted to our hospital, complaining of high fever, chills and skin rash on 5-12 days after working in the field. Based on laboratory examinations and one (or two) typical eschar, a tentative diagnosis of tsutsugamushi disease was made and all patients became better soon after the therapy with intravenous administration of minocyclin (200 mg/day). The high titer of serum antibody to Karp type Rickettsia (Orientia?) tsustugamushi was detected by an immunoperoxidase test (IP) in most of the patients, and also a Karp-like strain was isolated from only one patient, probably due to low virulence to mice. The agricultural areas along the Agatuma and Nakuta rivers in the northern foot of Mt. Haruna have been well known as the most endemic foci of the disease in Gunma Pref. Nevertheless, it was suggested that outbreaks of the disease might be potentially wide-spread throughout this Pref., when the prevalences of the disease were evaluated as incidences to a hundred thousand inhabitants or adjusted by the density of agricultural populations of each administrative divisions. As most of the patients in Gunma Pref. have been officially reported in autumn, a statistical trial indicates that there is a significant correlation between the levels of temperature and outbreaks of the disease in autumn.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Effects of switching from a high-fat diet to a low-fat diet on tumor proliferation and cell kinetics of 7,12-dimethylbenz(a)anthracene-induced mammary carcinoma in rats.

We investigated the stimulatory effect of a high-fat diet on tumorigenesis, tumor proliferation and cell kinetics of 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas in Sprague-Dawley rats, and sought to determine whether switching the animals from a high-fat diet to a low-fat diet would suppress tumor proliferation and cell kinetics. The high-fat diet significantly stimulated tumorigenesis, tumor proliferation and cell kinetics. After the animals were switched from the high-fat diet to the low-fat diet, however, tumor growth decreased, the BrdUrd labeling indices of tumors significantly decreased, and the potential doubling times of tumors significantly increased. Therefore, switching from a high-fat diet to a low-fat diet may improve the prognosis of breast cancer.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1992

Disulfide bond cleavage of human fibrinogen by cis-diamminedichloroplatinum(II).

Disulfide bridges in fibrinogen (Fbg) were cleaved by cis-diamminedichloroplatinum(II) (cis-DDP). Incubation with 120 molar excess of cis-DDP at pH 7.4 and 37 degrees C in the presence of EDTA resulted in cleavage of seven disulfide bridges out of 29. In the presence of calcium, however, the number of cleavages were reduced to four. The result indicates that calcium, which has three high affinity sites on Fbg, protects disulfide bridges from the rupture. Thrombin clottability was examined by turbidity measurement. The cis-DDP treated Fbg was shown to give a decreased fiber thickness. As the cleavage proceeded, the clotting ability of Fbg decreased.

Cisplatin↗

PubMed1992

Hormonal modulation of prolyl endopeptidase and dipeptidyl peptidase IV activities in the mouse uterus and ovary.

Prolyl endopeptidase and dipeptidyl peptidase IV are proline-specific peptidases, and are ubiquitously distributed in various tissues in mammals. The specific activities of these peptidases in both uterus and ovary were examined in the SHN strain of mice at estrus or diestrus. A marked change in prolyl endopeptidase activity was found in the uterus and ovary in intact mice during the estrous cycle, the activity being high at estrus and low at diestrus. In ovariectomized mice, prolyl endopeptidase activity was significantly higher in the uterus treated with progesterone or estradiol than in the uterus treated with vehicle oil only or a dopamine antagonist (perphenazine) which stimulates prolactin secretion. On the other hand, notable change in dipeptidyl peptidase IV activity during the estrous cycle was found only in the uterus of intact mice. The activity was low at estrus and high at diestrus. In ovariectomized mice, the uterus exposed to estradiol showed a lower dipeptidyl peptidase IV activity than the uteri treated with progesterone, the dopamine antagonist or vehicle oil. These findings reveal that there is a close correlation between the circulating level of ovarian steroids and the activities of these proline-specific enzymes.

Animals↗

PubMed1992

IgE, IgG, and IgG4 antibody titers to fractionated house dust mite antigens in nasal allergy patients.

Using 6 fractions differing in molecular weight of Dermatophagoides pteronyssinus (Dp)-antigen, we measured by enzyme-linked immunosorbent assay (ELISA) the titers of specific IgE, IgG and IgG4 antibodies against Dp antigen in sera of allergic subjects who were sensitive to house dust mite. We intended to evaluate which Dp fraction acts as the major antigenicity for allergic subjects. Results were as follows: 1) In comparison with normal controls, the titer of IgE antibody specific to crude Dp antigen was evaluated, but no significant difference was found among the titers of IgE antibody against each Dp fraction. 2) The titer of IgG antibody against the fraction with a high molecular weight (190 KD, 95 KD) was significantly higher than the titer of the 15 KD fraction in the nasal allergy patients. 3) The 15 KD fraction induced significant elevation of the titer of IgG4 antibody. It suggests that the low molecular weight fraction may act as the major allergenicity of Dp-antigen for inducing both IgE and competitive IgG4 antibodies, although other fractions induce significant IgE responses in patients with nasal allergy.

Adolescent↗

PubMed1992

[Primary tumor of the ureteral stump following nephrectomy for non-malignant disease. A case report].

Primary tumor in the ureteral stump is rare. A 66-year-old woman visited our hospital because of microscopic hematuria. She had undergone right nephrectomy for the contracted kidney 36 years ago. Intravenous pyelography and cystoscopy showed no positive findings for hematuria. But urine cytology indicated class V. The flexible ureterorenoscopy disclosed a nonpapillary sessile tumor in the ureteral stump. We also did the biopsy of the tumor under the direct vision before open surgery. The specimen showed transitional cell carcinoma, grade 3. The ureteral stump was successfully removed. The flexible ureterorenoscopy was most useful for the diagnosis in this case.

Aged↗

PubMed1992

[Percutaneous nephrostomy versus the placement of double pigtail ureteral stent for the treatment of postrenal failure secondary to malignancies].

From August 1989 through September 1991 we performed percutaneous nephrostomy under ultrasonic guidance in 26 kidneys of 25 patients. We also indwelled double pigtail ureteral stents by endoscopy in 14 kidneys of 13 patients. No patients died because of renal failure. The survival was dependent on progression of primary disease and performance status. Neither significant nor life-threatening complications were encountered. The difference in the improvement of renal function between nephrostomy group and stent group was not statistically significant. Although the indwelling ureteral stent method requires no external drainage bag, this method has certain drawback such as occasional obstruction of stent. Especially in poor risk patients, percutaneous nephrostomy technique seems to be better than placement of double pigtail ureteral stent in the treatment of postrenal failure secondary to malignancies.

Adult↗