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Biomedical subjects

J Tanaka

Publications and source records attributed to J Tanaka.

At least 667 records · Page 37Linked to original sources
PubMed1988

[Combined radiotherapy and chemotherapy for head and neck cancer].

There are 4 modalities of combined radiotherapy and chemotherapy which include (1) concurrent radiotherapy and chemotherapy, (2) sequential use of radiotherapy and chemotherapy (pre-radiation chemotherapy), (3) pre-radiation chemotherapy followed by concurrent radiation and chemotherapy, and (4) alternating use of radiotherapy and chemotherapy based upon Looney's hypothesis. We studied concurrent use of radiotherapy and UFT by means of animal experimentation and clinical trials. The results obtained revealed that UFT was a most suitable agent together with 5-fluorouracil for concurrent application of radiotherapy and chemotherapy. Neoadjuvant chemotherapy including pre-radiation chemotherapy was also studied in cases of maxillary sinus carcinoma and nasopharyngeal carcinoma. From the results, it seemed desirable to use cisplatin and bleomycin analogs sequentially in combined chemotherapy and radiotherapy. Neo-adjuvant chemotherapy should be studied successively to improve local tumor control rates and prevent distant metastases. For future perspectives, new trials of alternating radiotherapy and chemotherapy based upon Looney's hypothesis seem necessary.

Animals↗
PubMed1988

[Indications for limited hepatic resection in hepatocellular carcinoma].

Indications for limited hepatic resection in patients with hepatocellular carcinoma were evaluated by retrospective and clinicopathologic analysis of postoperative cases. Particular attention was paid to hepatic functional reserve and long-term prognosis. In our department, in order to estimate the hepatic functional reserve, indocyanine green clearance test (ICG), Child's classification and the oral glucose tolerance test have been applied. For instances, the incidences of hospital deaths were 17% and 19% in cases with an ICG-K value below 0.06 and between 0.06 and 0.08, which were high, compared with 6% and 3% in cases ICG-K values of with 0.08-0.10 and 0.10-0.12. On the other hand, by clinicopathologically analyzing 18 surviving patients or those surviving without recurrence for over 3 years after hepatic resection and 41 cases of small hepatocellular cancer less than 3 cm in diameter, those with capsule formation and without portal tumor invasion, intrahepatic metastasis and capsular invasion had a good long-team prognosis without recurrence even following limited resection. Particularly, patients with a surgical margin of over 1cm between the tumor and cut surface were candidates for long, non-recurrence survival. Form these results, the indications for limited hepatic resection for hepatocellular carcinoma were considered to be on ICG-K value of less than 0.08 in hepatic function and cases without venous invasion and extracapsular tumor invasion. In other cases, it is recommended that limited resection should be followed by multidisciplinary treatment.

Carcinoma, Hepatocellular↗
PubMed1988

[Crystal morphology of cholesterol monohydrate in cholesterol gallstones and gallbladder bile].

To understand the pathogenesis of cholesterol gallstones from a crystallographic point of view, we investigated gallstones and precipitates in gallbladder bile by the optical method used in crystallography. First, ground thin sections of cholesterol gallstones in 28 cases were examined by a polarizing microscope. The crystalline fragments which were peeled off from gallstones by sonication were also examined in the same manner. Secondly, the cholesterol monohydrate crystals in gallbladder bile were examined by a polarizing and phase contrast microscope. The bile samples were obtained from 15 patients with cholesterol gallstones by the needle puncture of gallbladder during surgery. The results of observation were as follows. 1) The cholesterol gallstones were composed of many small plated cholesterol monohydrate crystals aggregated radially. 2) Each small plated crystal was grown by the lateral growth mechanism in bile. Spiral growth patterns were often observed on the (001) faces. 3) The cholesterol gallstones were formed by two successive mechanisms: The aggregation of cholesterol monohydrate crystals and the lateral growth of each single crystal.

Bile↗
PubMed1988

[Lengthening middle hand and finger segment stumps by external distraction devices following traumatic amputations and in congenital abnormalities].

Since November 1984, lengthening of metacarpals and digital phalanges by a distraction apparatus has been performed in six metacarpal bones and four phalangeal bones in nine patients (four females, five males). The age ranged from 14 to 59 years (average 36). The follow-up period was from two to 28 months (average 16). Lengthening was performed by two kinds of external distraction devices, the Ikuta external fixateur for metacarpals and the mini-Hoffmann-device for phalanges. The achieved elongation of the metacarpal bones varied from 26 mm to 30 mm (average 28.8 mm), and of the digital phalanges from 10 mm to 17 mm (average 13.5 mm). During the operation, the bone was distracted primarily about 5 mm and thereafter it was gradually distracted at a rate of 0.5 to 1 mm per day. Blood supply and subjective complaints were examined carefully. During distraction, following complications were observed: Fracture of grafted bone, necrosis of free grafted skin, rupture of a tendon with neglected lesion and delayed spontaneous bone union between the fragments. It is emphasized that skin, tendons, and other soft tissues around the thumb and fingers to be elongated should be intact and that the gap should be filled with an en-bloc bone graft. This facilitates early union in spite of a relatively short period of immobilization. Because of the relative simplicity of the method, no microsurgical technique is required. The main advantage of the procedure is that the lengthened digit retains its original sensation, vascular supply and some mobility. It is a useful procedure especially when a patient does not want to sacrifice another digit.

Adolescent↗
PubMed1988

Cerebral autoregulation during deep hypothermic nonpulsatile cardiopulmonary bypass with selective cerebral perfusion in dogs.

We evaluated effects of hypothermic cardiopulmonary bypass on the cerebral circulation and metabolism of six dogs over a temperature range of 37 degrees to 20 degrees C under alphastat acid-base regulation (uncorrected for body temperature). Cerebral metabolic rate for oxygen was determined from the difference between arterial and sagittal sinus blood oxygen contents, and direct cerebral blood flow measurements of the venous outflow from the isolated sagittal sinus. After core cooling at a constant perfusion flow rate of 80 ml/kg/min, cerebral blood flow significantly reduced to 10.0 +/- 1.1 ml/100 gm/min at 20 degrees C (20% +/- 2% of that at 37 degrees C) because of an increase in the cerebral vascular resistance (339% +/- 48%). Cerebral metabolic rate for oxygen reduced to 18% +/- 2%. The upper body vascular resistance decreased to a greater extent than the lower body resistance (37% +/- 4% versus 82% +/- 12%). In the selective cerebral perfusion system at 20 degrees C, when perfusion pressure (mean carotid arterial pressure minus central venous pressure) was lowered from 90 mm Hg by graded reduction of the perfusion flow rate, cerebral blood flow remained constant down to a perfusion pressure of 40 mm Hg, then steeply declined. Cerebral metabolic rate for oxygen also kept a constant level down to 30 mm Hg, then fell abruptly. Definite autoregulatory response was detected even in profound hypothermic nonpulsatile cardiopulmonary bypass. These results suggest that cerebral perfusion flow should be regulated so as to keep the perfusion pressure within the range of cerebral autoregulation to prevent cerebral ischemia or hyperperfusion, especially during selective cerebral perfusion for operations on the aortic arch.

Animals↗
PubMed1988

[Radical excision followed by reconstruction of recurrent cancers of the head and neck].

Various modalities of treatment for recurrent cancers of the head and neck were studied and discussed, focusing especially on radical excision followed by reconstruction. Thirty-two patients with recurrent cancer of the head and neck were given this treatment over a 12-year period. Pectoralis major myocutaneous flap was most commonly used for reconstruction, while free latissimus dorsi myocutaneous flap with microneurovascular anastomosis was used for total cheek defect after surgery for cancer of the maxillary sinus. Five-year survival was 62% in cases of radical excision followed by reconstruction. Simple resection of recurrent lesions was conducted in 36 cases and the 5-year survival was also 62%. Radical neck dissection was performed in 22 cases in which cervical node metastases developed after control of the primary tumor, and the 5-year survival was 52%. On the other hand, the 5-year survival was not obtained in cases treated with radiotherapy alone in this series, while the 5-year survival was only 1% in cases treated with chemotherapy alone. It was concluded that surgery was the most reliable treatment for recurrent cancers of the head and neck, and that radical excision followed by reconstruction played an important role as salvage surgery.

Adult↗
PubMed1988

[Respiratory function of mitochondria fractionated from isolated hepatocytes of rats with obstructive jaundice].

Obstructive jaundice model was created using rats by the ligation of bile duct. One, 2, 3 weeks later, the respiratory function and morphology of the hepatic mitochondria were comparatively evaluated between mitochondria directly fractionated from liver tissue and mitochondria from isolated hepatocytes. Respiratory function of the former deteriorated with the duration of jaundice. ATP synthesis decreased to 75% of the control at 1 and 2 weeks, and 58% at 3 weeks after ligation. On the contrary, it was 97%, 88% and 87% of the control. On the contrary, it was 97%, 88% and 87% of the control at 1, 2 and 3 weeks in the latter. By electron microscopic examination, the size of mitochondria of the jaundiced liver is inconsistent and smaller in general than the control. These data suggest that the deterioration of mitochondrial function in the jaundiced liver is not caused mainly by the disturbance of mitochondria themselves, but caused by the respiratory inhibitory factors which exist around the mitochondria.

Animals↗
PubMed1987

Subfornical organ and hypothalamic paraventricular nucleus connections with median preoptic nucleus neurons: an electrophysiological study in the rat.

The role of pathways from the subfornical organ (SFO) to the hypothalamic paraventricular nucleus (PVN) through the median preoptic nucleus (MnPO) in regulating the activity of putative vasopressin (VP)-secreting neurons in the PVN was examined in urethane-anesthetized male rats. The activity of the majority (79%) of SFO neurons antidromically identified as projecting to the MnPO was excited by microiontophoretically (MIPh) applied angiotensin II (ANG II) and the effect was blocked by MIPh-applied saralasin (Sar), an ANG II antagonist. Identified SFO neurons that were excited by MIPh-applied ANG II were also excited by intravenously administered ANG II. Electrical stimulation of the SFO produced orthodromic excitation (48%) or inhibition (24%) of the activity of MnPO neurons antidromically identified as projecting to the PVN. Identified MnPO neurons that were excited by SFO stimulation were also excited by MIPh-applied ANG II, while the remaining neurons were not affected. The excitatory responses to SFO stimulation and to MIPh-applied ANG II were both blocked by MIPh-applied Sar, whereas the inhibitory responses to SFO stimulation were not affected. ANG II injected into the region of the SFO produced either an excitation (55%) or no effect (45%) on the activity of identified MnPO neurons. Electrical stimulation of the MnPO produced orthodromic excitation (27%) or inhibition (23%) of the activity of putative VP-secreting PVN neurons. ANG II injected into the region of the MnPO produced either an excitation (31%) or no effect (69%) on the activity of putative VP-secreting PVN neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1987

The A1 noradrenergic region enhances the responsivity of hypothalamic paraventricular neurohypophyseal neurons to inputs from the subfornical organ in the rat.

The action of the A1 noradrenergic neurons of the ventrolateral medulla on the responsiveness of neurohypophyseal neurons in the rat hypothalamic paraventricular nucleus (PVN) to inputs from the subfornical organ (SFO) was examined in antidromically identified PVN neurons that respond to electrical stimulation of both the SFO and A1 region. In both putative vasopressin (VP)-and oxytocin (OXY)-secreting PVN neurons that were classified according to their spontaneous firing patterns and their responsivity to baroreceptor activation, prior stimulation of the A1 region did not affect the short latency brief duration excitatory response induced by SFO stimulation. Simultaneous stimulation of the A1 region significantly enhanced the long latency prolonged excitatory response induced by SFO stimulation and the enhancement was blocked by microiontophoretically applied phentolamine, and alpha-adrenoceptor antagonist, but not by timolol, a beta-adrenoceptor antagonist. Simultaneous stimulation of the A1 region also significantly enhanced the inhibitory response induced by SFO stimulation and the enhancement was blocked by microiontophoretically applied timolol, but not by phentolamine. These results suggest that the A1 region may act to enhance the partial excitatory (via an alpha-adrenoceptor mechanism) and inhibitory SFO inputs (via a beta-adrenoceptor mechanism) to the PVN neurohypophyseal neurons as a modulatory action.

Animals↗