Biomedical subjects

M Ikoma

Publications and source records attributed to M Ikoma.

32 records · Page 2Linked to original sources

PubMed1990

Mechanism of the unique susceptibility of deep cortical glomeruli of maturing kidneys to severe focal glomerular sclerosis.

The alterations in single glomerular hemodynamics, glomerular size, and development of glomerular sclerosis after subtotal nephrectomy were assessed in approximately 32-d-old young and greater than 3-mo-old adult Munich-Wistar rats. In 6 wk, young rats developed more pronounced glomerular sclerosis and more marked elevation in blood urea nitrogen. The deep (versus superficial) cortical region of young rats was characterized by having a greater number of glomeruli with advanced sclerosis. Single nephron glomerular filtration rate of superficial glomeruli of the young increased to a much greater extent than whole kidney glomerular filtration rate, whereas there were comparable post-subtotal nephrectomy increases in whole kidney glomerular filtration rate in these two age groups, indicating that the deep glomeruli were exposed to a lesser hemodynamic load than were the superficial. Since the remnant nephrons of young and adult rats achieved equally high glomerular pressures and comparably large glomerular size shortly after subtotal nephrectomy, the unique susceptibility of young glomeruli to sclerosis is attributed to the intrinsic property of these glomeruli, rather than the abnormal hemodynamics or stimuli promoting hypertrophy and mesangial matrix accumulation imposed upon the glomeruli.

Age Factors↗

PubMed1989

Effects of antihypertensive drugs on glomerular morphology.

We quantitated the glomerular size and the degree of sclerosis simultaneously in individual glomeruli with the use of three-dimensional histological analysis on serial sections obtained from remnant kidneys with highly heterogeneous glomerular lesions after subtotal nephrectomy (sNPX). Four to six weeks after sNPX (Group I, N = 7), 90% of glomeruli had mild sclerosis (sclerosis index, SI; less than 1.5 on a 0 to 4 scale) with a strong positive correlation between the maximum planar area of glomerulus (PAmax) versus SI. Twelve weeks after sNPX (Group II, N = 6) more than 50% of glomeruli had advanced sclerosis (average SI:1.88), and a significant positive correlation was again found between PAmax and SI in glomeruli with mild to modest sclerosis (SI less than 1.5), whereas these two variables were correlated inversely in glomeruli with advanced sclerosis. Administration of enalapril (50 mg/liter drinking water) or hydralazine (200 mg/liter) + hydrochlorothiazide (50 mg/liter) for 12 weeks (Group III, N = 12) markedly attenuated the sclerosis to comparable degrees (average SI: 0.15 vs. 0.22). The former antihypertensive therapy decreased glomerular capillary hydraulic pressure (PGC) to normal range, whereas the latter triple drug therapy was largely without effect on PGC. Of note, the positive correlation between SI and PAmax remained unaffected by these anti-hypertensive drugs. SI of the glomeruli from both treated groups was expressed as a first-order function of PAmax. The correlation coefficient is identical to that found in non-treated Group II remnant glomeruli, so that the degree of sclerosis is mathematically uniquely correlated with the glomerular size, regardless of drug treatment. Thus, within a given remnant kidney, the magnitude of glomerular hypertrophy has a direct correlation with the degree of sclerosis, while the altered glomerular hemodynamic pattern has little modulatory role in determining the magnitude of this hypertrophy. Enalapril and triple drug therapy, at equi-depressor doses in regard to systemic blood pressure, had identical potency in sparing glomerular structure. The primary determinant for this antisclerotic potency appears to be related to the drugs' potency to inhibit glomerular growth rather than an effect on the abnormal hemodynamics which develop in the glomerulus.

Animals↗

PubMed1989

Inherited deficiency of the seventh component of complement: studies of C7-consuming activity.

Neither the hemolytic activity nor the protein level of the seventh component of serum complement (C7) was detectable in an 8-year-old girl with nephritis, but in her parents and her brother, they were about half of the normal level. The patient was a homozygote type with a complete deficiency of C7 while her parents and brother were all heterozygote type with a partial deficiency of C7. C7-consuming activity was demonstrated in the native serum of the patient with complete C7 deficiency, and it was found that large amounts of C56 were readily generated upon incubation of the patient's serum with zymosan. It is proposed that the C7-consuming activity in the native serum of this patient is due to small amounts of C56 generated during the activation of serum complement by some kind of infection such as a common cold.

Child↗

PubMed1988

[Preoperative intra-arterial infusion chemotherapy in locally advanced primary breast cancer-tissue concentrations of 5-fluorouracil and adriamycin, and the histological evaluation].

The effect of preoperative intra-arterial infusion of mitomycin C, 5-fluorouracil (5-FU) and adriamycin (ADM) were studied in seven patients with locally advanced breast cancer, including five inflammatory carcinomas, and a patient with stromal sarcoma of the breast. Reducing rate of the primary tumor of more than 30% was observed in all cases, and remarkable degenerative changes of tumor cells were histologically noted in six out of eight surgical specimens. The tissue concentrations of 5-FU and ADM were also studied in five breast cancer patients. There was no correlation between the concentration of 5-FU or ADM and histological effect. In intra-arterial infusion, ADM seemed to have a high affinity to the regional lymphnode and breast tumor, compared to normal breast tissue and might also be applicable to the control of lymphnode metastasis. Three out of six cases which received radical mastectomy subsequently had recurrence except in the regional lymphnodes and the prognosis was unsatisfactory (5 year survival was 2/4). Other alternative or multi-disciplinary treatment seems to be necessary for improving the survival rate.

Adult↗

PubMed1986

[Undifferentiated carcinoma of the pancreas with a choriocarcinomatous feature producing human chorionic gonadotropin].

An undifferentiated carcinoma of the pancreas in a 50-year-old man was found to be associated with a very elevated level of serum hCG. Syncytiotrophoblastic tumor cells were seen sporadically in the cancer nest, and they showed diffuse positive staining for hCG by immunohistochemical techniques. Positive staining for hCG was also observed in a few mononucleated cancer cells. The results indicated ectopic production of hCG by pancreatic cancer with a choriocarcinomatous feature and tended to support the hypothesis of the retrodifferentiation theory holding that choriocarcinoma is derived from a pre-existing pancreas cancer through metaplastic proliferation.

Carcinoma↗

PubMed1984

[Radical operation for rectal cancer to preserve anorectal, urinary and sexual function].

Recently, preservation of physiological functions have become to be considered in the operative treatment for rectal cancer. Dysfunction caused following radical operation for rectal cancer is divided into two parts as follows, (1) disturbance or loss of anorectal function due to sacrifice of the anus in abdomino-perineal resection and decrease function as fecal reservoir following anal sphincter preserving resection of the rectum. (2) anorectal, urinary and sexual dysfunction following surgical injury to the autonomic nerves by pelvic lymph nodes dissection. Our conceptions of the indication for sphincter preserving operation and for wide dissection of pelvic lymph nodes which cause severe dysfunction of urinary and sexual functions postoperatively were discussed.

Anal Canal↗

PubMed1983