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Biomedical subjects

M Niizuma

Publications and source records attributed to M Niizuma.

13 recordsLinked to original sources
PubMed1992

Myasthenia gravis developing after discovery of thymoma.

We report 4 cases of myasthenia gravis in which myasthenic symptoms developed after a thymoma was known to be present. They include 3 invasive thymomas and one thymoma. In 3 of them, myasthenic symptoms developed 2-7 months after removal of the thymoma; in 1 case, myasthenic symptoms developed 11 years after the thymoma was known to be present. We also discuss here the possible pathogenetic mechanism of post-thymomectomic myasthenia gravis, and propose that it is due to the natural course of the disease.

Adult↗
PubMed1992

[Myasthenia gravis and steroid therapy].

In the past 20 years, we experienced 242 myasthenic patients in our hospital. Fifty five cases were administered high doses of adrenocorticosteroid hormone for a long time. Among them, we analysed 39 cases with complete clinical records from admission to the present. We analysed 5 additional cases in whom responses to the therapy somewhat unique in that four cases have not shown any improvement until the drug was reduced to certain dosages, and in the 5th case change of method from alternate-day to every day brought good recovery of the symptoms. As a result, adrenocorticosteroid hormone was effective for 100% of the patients in this series. However, complete remission appeared in the above mentioned 10 patients (26%), after 2-3 years' continuous administration. Prognosis was far better in those who showed shorter durations between the onset of the disease and thymectomy or thymectomy than in those of longer one. In these cases, the maximum daily doses were 60-100 mg in alternate-day administration, and the total amount of prednisolone was 9-15 g in individual cases. Through data of these cases, it is recommended that the maximum dosage is to be continued for as long as 2 to 19 weeks with average 7 weeks.

Adolescent↗
PubMed1989

Model of neural visual system with self-organizing cells.

This paper describes a model of a neural visual system of a higher animal, in which the capability of pattern recognition develops adaptively. To produce the adaptability, we adopted "self-organizing cells," and with them modeled feature-detecting cells which were discovered by Hubel and Wiesel and whose plasticity was found by Blakemore and Cooper. Combining the "self-organizing cells" and the learning principle of a Perceptron-type system, we constructed a model of the whole visual system. The model is also equipped with an eye movement control mechanism for gazing, which reduces the number of "self-organizing cells" required for pattern recognition, thus contributing to their quick self-organization. Computer simulation and an experiment using a hardware simulator showed that "self-organizing cells" quickly become sensitive to the features often seen and that the resulted system can classify patterns with a rather small number of feature-detecting cells.

Computer Simulation↗
PubMed1989

Total replacement of the bladder with an intestinal pouch for normal micturition after cystectomy.

Between May 1987 and April 1988, seven male patients aged 43-69 years underwent an operation for total replacement of the bladder with an intestinal pouch for normal micturition after cystectomy. In five, the detubularized ileocecocolic segment was used as the internal reservoir and, in the other two, the ileum or the sigmoid colon was used because of a severe adhesion of the ascending colon due to previous surgery. Three months after surgery, six patients had a vesical capacity of 300 ml or more and could excrete a maximum 200-300 ml urine at one voiding. Daytime continence was achieved in six patients in three months, and night-time continence in five patients in six months. No abnormalities in serum electrolytes, acid-base balance or renal function were observed during follow-up periods of 8-16 months. The patients were enthusiastic about this procedure, including the patient requiring occasional self-catheterization to overcome his incontinence. The follow-up periods have been short, but this method seems promising as a new internal diversion.

Aged↗
PubMed1989

Early lesions and natural progression of bladder carcinoma (minute bladder carcinoma).

Morphological analyses of minute bladder carcinomas (less than 5mm in diameter) and their natural progression to advanced carcinomas were examined. There were 71 minute carcinomas in 25 cases, the highest number in any one case being eight. The growth forms of the 71 minute carcinomas were classified into six types: papillary (35), Brunn's nest-like (20), intermediate between those two (9), simple displacing (3), inverted papillary (2) and invasive (2). There appeared to be two kinds of advanced papillary carcinoma, one forming a papillary tumor from the onset of progression, and the other, initially exhibiting Brunn's nest-like, intermediate or simple displacing tumors and finally forming papillary tumors. Some of the papillary carcinomas seemed to have developed from papillomas. Two pathways to invasive carcinomas from papillary tumor were suggested: one showing invasive growth directly from the papillary tumor, the other developing invasive changes in the proliferative processes from Brunn's nest-like or intermediate tumors. Invasive growths occurred in tumors of G2 or over and in those in which the character of the tumor was changed to that of squamous cell carcinoma. They appeared to be more frequent (four cases out of 13 compared with one out of 10) in the advanced papillary carcinomas which had seemingly developed from the various kinds of minute tumor other than papillary. Invasive minute carcinoma was regarded as being an early stage of advanced non-papillary invasive carcinoma.

Adult↗
PubMed1986

Quantitative analysis of ultrasonogram of the prostate.

In 51 cases with prostatic cancer, 88 with prostatic hypertrophy, 109 with prostatitis, and 174 normal subjects, the following five parameters were calculated from prostatic ultrasonograms scanned transrectally; prostatic weight (W), presumed circle area ratio (PCAR), anteroposterior diameter/transverse diameter (ATR), asymmetry index (ASI), and dissimilarity index (DSI). The W and PCAR were higher in cancer and hypertrophy than in prostatitis and normal subjects. The ATR and ASI were higher in cancer. The DSI was lower in hypertrophy. A canonical discriminant analysis using these five parameters disclosed two canonical variates that were useful to separate the disease entities: one separated cancer and hypertrophy from prostatitis and normal subjects, and the other separated cancer from hypertrophy. The coefficients of these variates indicated that cancer was separated from prostatitis and normal subjects by increases in W and ATR and from hypertrophy by the greater effect of increases in ATR (as compared to PCAR) and the small increases in W.

Biometry↗
PubMed1981

Transurethral ultrasonotomography of the prostate.

Newly developed transurethral ultrasonic scanners were used to study 20 patients with histologically proven prostatic cancer. Fifty-two patients with or without other prostatic disease were also evaluated. The characteristic findings of prostatic cancer were asymmetry of the shape (85%), ill-defined contour (75%), protruded areas from the boundary (70%), elongation of anteroposterior diameter (65%), and enlargement of the prostate (65%). In addition, transurethral ultrasonography delineated a clearer contour of the prostate compared with the transrectal procedure.

Humans↗
PubMedDate not supplied

Biochemical study of different conditions of type 2C muscle fiber in rat.

Type 2C muscle fibers were histochemically and biochemically examined under three different conditions in rats: in the neonatal stage, after neonatal denervation and on regenerating process after bupivacaine-induced injury. On histochemical examination, soleus was found to contain up to 90% of type 2C fiber in every condition, whereas both gastrocnemius and extensor digitorum longus contained 40-70%. On biochemical analysis, triglyceride was the smallest and glycogen was the largest in amounts in neonatal muscles, triglyceride was the largest and glycogen was lowest in amount in neonatal denervated muscles, while both triglyceride and glycogen were low in amounts in bupivacaine-treated muscles. These results suggested that although histochemical characteristics are the same, significant differences in biochemical properties exist between type 2C fibers in these three different conditions.

Animals↗