Biomedical subjects
Publications and source records attributed to T Hirota.
A new multipurpose head frame has been designed for microneurosurgery. It consists of a head holder with a frame to hold self-retaining brain retractors, hand rests, instrument holders, a plate for cotton patties, and skin-flap retractors. It has been satisfactorily used in 100 operations for 1 year.
Three new 8N-alkyl analogues of roseoflavin (MM), i.e., 8-ethylamino- (EH), 8-methylethylamino- (ME), 8-diethylamino-8-demethyl-D-riboflavin (EE), their tetraacetates, and 8-amino-8-demethyl-D-riboflavin (HH) tetraacetate, were synthesized. A relation between the anti-riboflavin activity and the chemical structure of 8N-alkyl analogues (8N-methyl, ethyl) was studied by a restoration by riboflavin (RF) of inhibitory effect of the analogues on a growth of Gram-positive bacteria, i.e., Sarcina lutea, Bacillus cereus, and Staphylococcus aureus. The inhibitory effect of most of the analogues was restored by RF. But in some cases, i.e., 8-methylamino-8-demethyl-D-riboflavin (MH) in Sar. lutea and MM in Staph. aureus, the effect was not completely restored. Apparently, the inhibition in early phase of growth was restored, but the maximum growth was still suppressed. The non-alkylated amino analogue (HH) showed only unrestorable suppression of maximum growth in Sar. lutea. Of restorable effect by RF of N-alkyl analogues, approximate decreasing orders of anti-RF activity were as follows. Dialkylated analogue greater than monoalkylated. HH showed insignificant anti-RF activity. In each group, methylated analogue greater than ethylated. In B. cereus monoalkylated analogues, and in Staph. aureus monoalkylated and EE showed no significant inhibitory effect. Redox potentials of the N-alkyl analogues were measured, and a definite relation between the chemical structure and the potential was found (RF = EE greater than ME greater than MM greater than HH greater than EH greater than MH). But the anti-RF activity of the analogues was not completely explained by the difference of the redox potential from RF.
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Epidemiologic and clinical studies conducted in the past 15 years have demonstrated striking differences in the biology of mammary carcinoma among Japanese and American women living in their native countries. These variations have, in part, been related to some differences in the characteristics of the primary tumors between the two groups. As part of a collaborative study we have had an opportunity to compare the stage of disease and to examine and compare histological sections of patients with breast carcinoma treated in 1973-74 at the National Cancer Center Hospital (NCH) in Tokyo and in 1974 at the Memorial Hospital (MH) in New York. The former group consisted of 216 and the latter of 555 carcinomas. Fewer patients in each group had axillary metastases than reported in a prior study of patients treated at MSKCC and in Tokyo 20 to 30 years earlier. Negative axillary nodes were now found in 58% of the MH patients and in 63% of women treated at the NCH. The magnitude of improvement in stage relative to the prior report was similar in both groups. However, it would appear that the change occurred mainly from the mid-1950s to the 1960s in New York and approximately 10 years later in Tokyo. Results of this study confirming prior reports were: (1) higher frequency of colloid and of medullary carcinoma with lymphoid stroma and lesser frequency of lobular carcinoma in the Japanese patients; (2) more intense lymphoid infiltrate in and around primary tumors in Japanese women; (3) higher frequency of rounded or circumscribed tumors in Japanese women; and (4) the more frequent occurrence of intralymphatic tumor emboli within the breast in American women. The difference in the frequency of lobular carcinoma was less striking when comparison was limited to patients with unilateral carcinoma.
Frequent adjustment of the angle and the focus of the operating microscope is the most important but troublesome manoeuvre during microneurosurgery. We have designed a new suspension and control system for the operating microscope. There is a magnetic lock system of all joints and axes for gross movement of the microscope and the other facility is a remote control microdriving system for fine adjustment of the focus either with the hand or a pedal control box. This system could effectively save operating time as well as surgeon's physical exertion.
The authors report a unique case of transient amaurosis occurring every time the patient flew in a jet plane and frequently when he drove up a mountain. X-ray examination showed dysplasia of the sphenoidal sinus and optic canals. The pathogenesis and the treatment of the amaurosis is discussed.
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Esophageal carcinomas were induced in three of five rabbits given 0.25% N-methylbenzylamine and 0.16% NaNO2 in their drinking water. The three rabbits with carcinoma had consumed more than 94 g of NaNO2 and had survived for more than 536 experimental days. The esophageal carcinomas were a slightly elevated type, and no polypoid lesions were seen. They were classified histologically as squamous cell carcinomas or adenosquamous carcinomas, or both. No metastases were found. The other two of the five rabbits died early in the experiment before any esophageal carcinoma had developed.
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Comparative study of the pressure and the resistance to slippage of several aneurysm clips was done. Knowledge of the physical characteristics of various clips, such as the pressure, maximum opening angle, and width and thickness of the blade is essential for their proper use.
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Leiomyosarcomas of the small intestine were found in dogs during experimental induction of gastric carcinoma by oral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Leiomyosarcomas were found most frequenly in the duodenum and jejunum, and occasionally in the stomach but never in the ileum, colon, or rectum. The leiomyosarcomas developed in all the dogs given 50 mug/ml of MNNG in deionized water to drink but not in dogs fed on porridge food made from standard pellet diet mashed with MNNG at the same concentration in tap water. Intestinal sarcomas developed in 3 months to 5 years after the end of MNNG administration, and frequently metastasized to the liver and/or the peritoneum.
In a series of 46 cases of pituitary adenomata (34 solid, 6 with yellow cyst, and 6 with hemorrhagic cyst), we found central scotomatous field defects in 8 patients. Of these 8 scotomatous cases 4 were associated with tumour containing a hemorrhagic cyst. We suggest that rapid expansion of the tumour is one of the principal etiological factors in the production of scotomatous instead of bitemporal field defects in patients with pituitary adenomas.
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