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Biomedical subjects

T Kadota

Publications and source records attributed to T Kadota.

At least 109 records · Page 6Linked to original sources

Somatotopic organization of the primary sensory trigeminal neurons in the hagfish, Eptatretus burgeri.

Primary sensory trigeminal projections were investigated in the hagfish following application of horseradish peroxidase (HRP) to the sensory branches. In our control preparations we were able to distinguish five sensory ganglia and their respective nerves. HRP application confirmed the almost exclusive relation of each of these nerves to their respective ganglia, with very little overlap. In normal frontal sections of the medulla oblongata, five columns of fibers surrounded by neuronal cell bodies could be clearly distinguished, but the number is probably fortuitous, for there was no one-on-one relationship with the five trigeminal ganglia. From their peripheral connections, we surmised that columns 1 and 3 handle general cutaneous sensation, columns 2, 4, and 5 handle taste sensation, and column 5 handles general mucous cutaneous sensation conveyed by utricular ganglion cells. Dorsally located columns received projections from nerves with dorsal peripheral connections, and more ventrally located columns received projections from nerves with ventral peripheral connections. This relation is the reverse of that seen in other vertebrates.

Afferent Pathways↗

Substance P-like immunoreactivity in the trigeminal sensory nuclei of an infrared-sensitive snake, Agkistrodon blomhoffi.

With the peroxidase-antiperoxidase immunohistochemical method we ascertained the presence of substance P-like immunoreactivity (SPLI) in fibers and cell bodies of the trigeminal sensory system of the pit viper, Agkistrodon blomhoffi. There are a few SPLI fibers each in the principal sensory nucleus and the main neuropil of the lateral descending nucleus (i.e., the infrared sensory nucleus); a moderate number in the descending nucleus; and a large number in the caudal subnucleus, the medial edges of the interpolar subnucleus, and the marginal neuropil of the lateral descending nucleus. About 30% of the cell bodies in the ophthalmic and maxillo-mandibular ganglia show SPLI, and of the two craniocervical ganglia, the proximal ganglion has many more cells with SPLI than the distal ganglion. The SPLI distribution in the common trigeminal sensory system is similar to that of mammals, and suggests that the function of this system is also similar. In the infrared that the function of this system is also similar. In the infrared sensory system, the differing distribution in the main and marginal neuropils suggests separate functions for these two structures in the system.

Afferent Pathways↗

Postsynaptic arch in the frog neuromuscular junction: paramembranous protuberances coating the inner surface of the postjunctional membrane.

The frog neuromuscular junction was fixed and processed for electron microscopy according to the method of rapid freezing followed by freeze-substitution. The synaptic structures, including cleft material, paramembranous cytoplasmic coating on the postsynaptic membrane, and subsynaptic cytoplasmic elements, were examined in thin sections. The basal lamina, about 50 nm thick, was seen to bisect a synaptic cleft approximately 100 nm wide. The lamina consists of two parts: the central dense line and the fine filaments protruding from it in the direction of the apposing postjunctional membrane. Present on the cytoplasmic surface of the postjunctional membrane are electron-dense protuberances, 41 +/- 5 nm in width and 27 +/- 5 nm in height (top to membrane centre). They are arranged in regular parallel rows, at 54 +/- 4 nm intervals (centre to centre). The paramembranous protuberance coats the inner surface of the postjunctional membrane at its apex as well as at the middle portion of the junctional process, pointing to its probable hairpin-like course in a transverse plane of the process. From its location and three-dimensional arrangement, this protuberance was termed the 'postsynaptic arch'. A filamentous meshwork is present just beneath the postjunctional membrane and extends into the cell interior. The submembranous meshwork appears to connect to the underlying bundles of cytoskeletal filaments. The possibility is discussed that the postsynaptic, electron-dense arch corresponds to the 43-kDa protein, a major alkaline-extractable protein thought to be associated with the cholinergic receptor molecules in the postsynaptic membrane.

Animals↗

Substance P-like immunoreactivity in the central retinal artery of the rabbit.

Substance P-like immunoreactive nerve fibers were identified in the central retinal artery of the rabbit using the peroxidase-antiperoxidase method. The fibers were seen to encircle the central retinal artery throughout its course in the main trunk of the optic nerve. No labeled fibers were seen in the central retinal vein or in the retinal blood vessels. It appears, therefore, that the central retinal artery and the retinal blood vessels are innervated by different nerve systems: the central retinal artery by one of the peripheral nerves, and the retinal vessels by the central nervous system.

Animals↗

The effect of laparoscopic multiple punch resection of the ovary on hypothalamo-pituitary axis in polycystic ovary syndrome.

To evaluate the hormonal effect of laparoscopic ovarian punch resection in polycystic ovary syndrome (PCO), seven PCO patients were examined for pulsatile gonadotropin secretions and pituitary sensitivity before and after operation. Marked reductions of luteinizing hormone (LH) pulse amplitudes, mean LH levels, pituitary LH responsiveness, and circulating androgen levels (P less than 0.05) were observed, 3 to 4 days and 6 weeks postoperatively. LH pulse frequency, follicle-stimulating hormone (FSH), and prolactin (PRL) did not change significantly. These results are consistent with the reported hormonal effects of wedge resection and suggest that the impairment of ovarian surface acts on the hypothalamo-pituitary axis to decrease pituitary hypersensitivity and the key factor behind the resultant hormonal change lies not deep inside the ovarian stroma but in the superficial ovarian capsule.

Adult↗

[Reproduction studies of carboplatin (I)--Intravenous administration to rats prior to and in the early stages of pregnancy].

Carboplatin, an oncostatic drug, was administered intravenously to male Crj: CD (Sprague-Dawley) rats for 63 days and to female rats of the same strain for 14 days prior to mating at dose levels of 1, 2 and 4 mg/kg/day. These animals were then mated under the consecutive administration of this drug and the females confirmed to be copulated were further dosed from day 0 through 7 of gestation. The summarized results obtained are as follows: 1. Carboplatin 2 mg/kg and higher suppressed body weight gains accompanied by the decreases in food and water consumption in male rats. Further, body weight gains were suppressed in female rats followed by the decreases in food consumption at the same dose levels. 2. Though there were no differences between dosed animals and controls regarding the organ weights, the incidence of necrosis of the tails around the injection site was increased in male rats at 4 mg/kg. 3. Carboplatin failed to affect the reproductive ability of both sexes. 4. As for fetuses, the mortality was elevated at 2 mg/kg and higher and the number of live fetuses reduced at 4 mg/kg, but the influences on prenatal development were not apparently observed for live fetuses even at the highest dose level. Based on these results, the no-effect dose level of carboplatin under the present experimental condition was estimated to be 1 mg/kg/day against parent rats of both sexes and their offspring.

Animals↗

[Reproduction studies of carboplatin (II)--Intravenous administration to rats during the period of fetal organogenesis].

Carboplatin, an oncostatic drug, was administered intravenously to pregnant Crj: CD (Sprague-Dawley) rats from day 7 through 17 of gestation at dose levels of 1, 2 and 4 mg/kg/day. The summarized results obtained are as follows: 1. Carboplatin 4 mg/kg suppressed the maternal body weight gains from day 13 through 20 of gestation. 2. Uterine weights were reduced in F0 dams at term at carboplatin 4 mg/kg. 3. Carboplatin 4 mg/kg brought the inhibition of fetal growth accompanied by the lowered values in fetal weights, crown-rump distances and tail lengths. Furthermore, the elevated incidences of unossified 5th and 6th sternum , as well as retarded ossification of sacrococcygeal vertebrae were also noted in this dose level. 4. The birth rate was reduced in neonates (F1) at carboplatin 4 mg/kg. 5. Body weight gains in male F1 rats were suppressed at carboplatin 4 mg/kg from 4 to 8 weeks of age. 6. Carboplatin 4 mg/kg decreased the brain weights on an absolute basis in female F1 rats, but failed to affect their postnatal differentiations, early behavioral developments, learning ability, motor activity or emotional development. 7. Reproductive ability in F1 rats of both sexes were not affected by carboplatin. 8. Influences on prenatal development were not apparently observed for F2 fetuses derived from F1 rats whose dams had ever received carboplatin during the organogenetic period. Based on these results, the no-effect dose level of carboplatin under the present experimental condition was estimated to be 2 mg/kg/day against dams and their offspring.

Animals↗

[Reproduction studies of carboplatin(III)--Intravenous administration to rats during the perinatal and lactation periods].

Carboplatin, an oncostatic drug, was administered intravenously to pregnant Crj: CD (Sprague-Dawley) rats from day 17 of gestation through day 21 of postpartum at dose levels of 1, 2 and 4 mg/kg/day. The summarized results obtained are as follows: 1. Maternal body weight gains were suppressed during the former part of the lactation period at carboplatin 2 mg/kg and higher. 2. Thymic weights were decreased and lung weights were increased in dams (F0) at carboplatin 2 mg/kg and higher. Further, ovarian weights were reduced in dams (F0) at carboplatin 4 mg/kg. 3. Carboplatin failed to affect the parturition of F0 dams. 4. Carboplatin did not affect the viability of newborns (F1), and postnatal differentiations, early behavioral developments, learning ability, motor activity or emotional development in F1 animals. 5. Carboplatin 4 mg/kg brought a suppression of pituitary weights after mating in F1 male rats and decreases of adrenal and genital organ weights at weaning in F1 female rats, but failed to affect their reproductive ability. 6. Influences on prenatal development were not apparently observed for F2 fetuses derived from F1 rats whose dams had ever received carboplatin during the perinatal and lactation periods. Based on these results, the no-effect dose level of carboplatin under the present experimental condition was estimated to be 1 mg/kg/day against dams and 2 mg/kg/day against their offspring.

Adrenal Glands↗

[Laparoscopic diagnosis and evaluation of danazol or gestrinone therapy for endometriosis in sterility].

In forty-six sterile women, endometriosis externa was diagnosed and classified laparoscopically. 21 patients were treated with Gestrinone 5mg-10mg/week and 25 patients were treated with Danazol 300mg-400mg/day for 6 months. The effects of these hormonal treatments were evaluated by second-look laparoscopy according to adhesion severity, number of blueberry spots and chocolate cyst size, as well as dysmenorrhea and other complaints. The results were as follows; 1) Dysmenorrhea was relieved in 60.0% of the Gestrinone-treated group and 45.5% of the Danazol group. 2) Adhesion was weakened or partially separated spontaneously in 66.7% of the Gestrinone group and 63.6% of the Danazol group. 3) Blueberry spots decreased in number or paled in 61.9% of the Gestrinone group and 75.0% of the Danazol group. 4) Chocolate cyst size became smaller in 60.0% of the Gestrinone group and 77.8% of the Danazol group. 5) Peritoneal fluid volume was not decreased after the hormonal treatments but the prostaglandin E2 concentration in peritoneal fluid was decreased (p less than 0.05) after Gestrinone therapy. 6) The patients complained of some side effects, liver function especially was disturbed in 48.0% of the Danazol group and 9.5% of the Gestrinone group. Hoarseness was complained of in 33.3% of the Gestrinone group and 12.0% of the Danazol group. 7) Finally, 23.8% of the Gestrinone group and 28.0% of the Danazol group conceived after the hormonal treatments.

Adult↗

[The clinical and hormonal effects of laparoscopic multiple punch resection (MPR) of the ovary in polycystic ovary syndrome].

Eleven women with polycystic ovary syndrome (PCO) were treated with Laparoscopic Multiple Punch Resection (MPR) of the ovarian follicle and capsule and studied by hormone analysis before and after MPR. In 90.9% of the patients, ovulation appeared to occur within 9 weeks and 63.6% conceived within 26 weeks. No changes in serum LH and FSH levels were seen before and after MPR, but testosterone levels which were in the upper normal range or slightly elevated before treatment were reduced after MPR. Endocrine responses to MPR were similar to those described previously after wedge resection. Laparoscopic MPR is a simple and least invasive method and makes it unnecessary to worry about periovarian adhesion after operation. Furthermore, other causes of infertility can be examined by laparoscopy. MPR appeared to be a promising alternative treatment for patients with PCO.

Adult↗

Primary neurons of the lateral line nerves and their central projections in hagfishes.

The hagfish lateral line system was studied by horseradish peroxidase transganglionic transport. The anterior lateral line nerve innervates the group of lateral line canals situated anteriorly to the eye, and the posterior lateral line nerve innervates the group of canals situated posteriorly to the eye. Although both nerves pass through the muscle fascia at the same point, each runs a different course to the brain. The anterior lateral line nerve runs near the trigeminal nerve and its ganglion is closely attached to the trigeminal ganglion, but both systems are completely independent. The posterior lateral line nerve runs independently of any other cranial nerve and makes a peculiar U-turn at the point of entry to the brain capsule. The anterior lateral line ganglion contains both cutaneous sensory cells (small to large cells) and lateral line sensory cells (small cells); from this ganglion projections run to both the trigeminal sensory nucleus (fine and thick fibers) and medial nucleus of the area acousticolateralis (fine fibers). The posterior lateral line ganglion contains only small lateral line cells that project fine fibers to the medial nucleus of the area acousticolateralis. There are no efferent components in this lateral line system, and its only afferent terminal field is the medial nucleus of the area acousticolateralis.

Afferent Pathways↗

Staging of bladder carcinoma by magnetic resonance imaging. A preliminary report.

Magnetic resonance imaging (MRI) of bladder carcinoma was performed in 10 patients who subsequently underwent operations for tumor staging. MRI was performed with a 0.1 T resistive magnetic resonance unit. Images were obtained in the transverse, coronal and sagittal directions with different repetition and echo times. Simultaneously, computed tomography (CT) was performed in 9 of the 10 patients. The accuracy of MRI and CT staging was then evaluated by comparison with the staging from pathologic diagnosis. All of the tumors, which were 2.3-6.3 cm in diameter, were readily depicted by both imaging techniques. The overall accuracy of MRI staging for the 10 patients in whom staging had been pathologically confirmed was 90%, while the accuracy of CT staging for the 9 patients was 55%. Although no statistically significant differences in accuracy between CT and MRI staging can be established on the basis of the above results because of the small number of patients included in this study, MRI appears to be a very useful modality for staging bladder carcinoma.

Adult↗

Chemoarchitectonics of the brainstem in infrared sensitive and nonsensitive snakes.

The crotaline snake Agkistrodon possesses infrared receptors, whereas the colubrid Elaphe quadrivirgata does not. We compared the histochemical activity of succinate dehydrogenase (SDH), monoamine oxidase (MAO), and acetylcholinesterase (AChE) in the brainstem of these 2 species, by the method of Nachlas et al. (1957), Glenner et al. (1957), and Koelle and Friedenwald (1949), respectively, and made the following observations. Visual system: The tectum opticum (TO) exhibited strong or moderate AChE and SDH activity in areas receiving retinal projections, i.e. the str. zonale (sz), str. fibrosum et griseum superficiale (sfgs), and narrow areas between small tight fasciculi of the tr. opticus. The sfgs was divided into 2 sublayers, a superficial and a deep, by the intensity of AChE activity. The deep sublayer of the sfgs and sfc of Agkistrodon were stained more strongly than other layers. Numerous fibers within the TO showed MAO activity. The entire sfgs of Agkistrodon was thinner than in Elaphe. The nucl. posterodorsalis showed moderate AChE, and weak SDH and MAO activity in Agkistrodon, but lack of AChE, weak SDH, and moderate MAO activity in Elaphe. Infrared system: This system was present only in Agkistrodon. The nucl. of the lateral descending trigeminal tract (dlV) and the nucl. reticularis caloris (rc) showed to moderate SDH activity in the main neuropil and/or perikarya. These nuclei were not conspicuous in AChE preparations. The marginal neuropil of the dlV had weak SDH, and moderate AChE and MAO activity. Common sensory trigeminal system: Moderate activity of the 3 enzymes was seen in the nucl. tr. descendens n. trigemini (dl). In the dorsomedial part of the nucl. interpolaris, the round limited portion was stained strongly for SDH and AChE. Cells of the nucl. tr. mesencephalicus n. trigemini showed strong SDH and AChE activity. Other regions: In Elaphe, there was strong to moderate AChE and SDH activity in the nucl. of the fasciculus longitudinalis medialis, nucl. centralis superior, raphe nuclei, and reticular nuclei, but only weak activity in Agkistrodon. We also found the following similarities in the 2 species. Strong to moderate AChE and SDH activity was observed in the motor nuclei of the cranial nerves, pretectal nuclei excepting the nucl. posterodorsalis, nucl. opticus basalis, and nucl. posterolateralis tegmentalis. Strong to moderate activity of the 3 enzymes together was detected in the nucl. interpeduncularis as found in other animals previously studied, and in the nucl. commissurae cornae dorsalis, nucl. cochlearis angularis, and the molecular and granular layer of the cerebellum.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholinesterase↗

Organization of the trigeminal and facial motor nuclei in the hagfish, Eptatretus burgeri: a retrograde HRP study.

We studied the trigeminal and facial motor nuclei of the hagfish by the retrograde HRP method. We distinguished 4 components in a single column of the motor nuclei of the trigeminal nerve and the facial nerve, viz., the pars magnocellularis of the trigeminal motor nucleus (mVm), the anterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp1), the posterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp2) and the facial motor nucleus (mVII). Although in Nissl preparations only the mVm could be distinguished from the rest of the nucleus, the boundaries of the other 3 components were clearly demarcated in HRP preparations. Intramuscular injections into two representative antagonistic jaw muscles revealed that there was no apparent topological organization of the neurons pertaining to the opening and closing muscles in the mVm and mVp1, but both antagonistic muscles were innervated bilaterally. Although the hagfish does possess a cartilaginous jaw, the organization pattern of the motor nuclei of the jaw muscles seems to be the most primitive of all living vertebrates.

Animals↗

Fenvalerate-induced granulomatous changes in rats and mice.

Wistar rats and ddY mice were fed diet containing 10 to 3000 ppm technical fenvalerate for the major portion of their life span. Microgranulomatous changes were observed in lymph nodes, liver and spleen of both rats and mice as well as in adrenals of rats. The no-effect level for microgranulomatous changes was 30 ppm for mice and 150 ppm for rats. Transmission electron microscopy of phagocytes in the granulomatous foci revealed needle- or rod-shaped crystalline bodies within the cytoplasm. To examine reversibility of the microgranulomatous changes, ddY mice were fed the diet containing technical fenvalerate at the levels of 1000 and 3000 ppm for 6 weeks, followed by rearing on the control diet for up to 12 months. The size and number of the microgranulomatous changes were reduced with time. The microgranulomatous changes were typical of foreign body granulomas; they did not have the appearance of granulomas formed in response to immunologic stimulus.

Adrenal Glands↗