Biomedical subjects

K Ojima

Publications and source records attributed to K Ojima.

At least 55 records · Page 3Linked to original sources

PubMed1997

Numerical variation and distributive pattern on microvascular cast specimens of vallate papillae in the crossbred Japanese cat tongue.

In order to examine in detail the numerical variation and distributive pattern of vallate papillae (VaP) on the lingual posterior dorsal surface of the crossbred Japanese cat tongue, macroscopic, stereoscopic and scanning electron microscopic studies by means of a microvascular cast specimen (MVCS) were carried out under the scanning electron microscope (SEM). Regardless of sex, there were 4-8 VaPs in number, with an average of 6, forming 2-4 pairs arranged by type which could be observed symmetrically or asymmetrically on both sides of the posterior dorsal region of the tongue surface. The results of this study showed that the distributive pattern of VaP can be classified into six forms: typical forms I (2 left and 2 right), II (3:3) and III (4:4); and forms IV (2:3), V (2:4) and VI (3:2) were atypical. It seems that there is every probability that statistically another atypical form (3:4), (4:2), (4:3) will appear in the future. Nevertheless, in a large number of studies on the lingual papillae of the cat tongue, 8 VaPs arranged in pairs by type have been found (form III (4:4)) has not yet been reported in the crossbred Japanese cat tongue.

Animals↗

PubMed1997

()-form distribution seen in microvascular cast specimens of the filiform and fungiform papillae on the anterior central dorsal surface of the cat tongue.)

Three-dimensional structures of the microvascular network of the filiform papillae (FiP) and fungiform papillae (FuP) on the cat tongue were observed by the corrosion cast method under a scanning electron microscope (SEM). FiP can be classified into five types, types I-V and FuP into four types, types I-IV according to the shape and size of the main process (MP) and the number of the accessory processes (AP) which are found on the anterior central dorsal surface. FuP (I-IV) were found to be distributed sporadically among FiP (I-V). Each of the types I-V of FiP were arranged the form of a in an oblique line running from the anterior central zone to the posterior peripheral zone in an orderly and geometrical fashion. Each of the types I-IV of FuP were scattered throughout in line of FiPs arranged in the form of a , the point of which is directed at right angles towards the apex. FiP play an important role in the drinking of milk and water, holding, masticating and swallowing the food and, after mixing the food with saliva, in the transporting of the food mass towards the pharynx. The MP of FuP was considered to be a modified form of the MP of FiP of the cat tongue and to function as part of a sense organ for taste.

Animals↗

PubMed1997

Angioarchitectural comparison of the fungiform papillae of the cat and rabbit using scanning electron microscopic specimens.

The functional and morphological characteristics of the fungiform papillae (FuP) on the anterior dorsal surface of the cat and rabbit tongues were studied and compared using a scanning electron microscope (SEM), because the comparison of the functional and morphological relationship of FuP in microvascular cast specimens (MVCS) between these tongues is as yet not clear. In both species, FuP were found to be distributed sporadically among the numerous filiform papillae (FiP). In the cat, in particular, FuP were classified into four types (FuP I-IV) according to the shape and size of a main process (MP) and the number of accessory processes (AP). Each FuP, (FuP I-III lay along oblique lines of FiPs) contained a MP and many APs lying at the anterior basal margin of the MP, whereas FuP IV contained only the small fishnet-ball-shaped MP. In the rabbit, however, only the similar size and shape of the capillary loops, resembling the carnation flower, were scattered among FiPs on the anterior dorsal surface of the fore-tongue. These results suggest that in comparing the functional sense mechanism in both species, the FuP of the rabbit tend to be more simple than those of the cat in respect to taste sense.

Animals↗

PubMed1997

Unusual post-mortem autolytic change in the liver: wavy transformation of hepatocytes.

An unusual morphologic change noted in the liver of a 21-year-old male who committed suicide by taking dimenhydrinate is described. The post-mortem interval was two days. Microscopically, there were no marked ante-mortem pathologic changes. In addition to the unusual post-mortem autolytic changes, such as disappearance of the hepatic cords and shrinkage of the hepatocytes, conspicuous way transformation of the hepatocytes, which was apparently never been reported before, was observed. This change could not be identified as an artifact, and it was assessed to be a type of autolysis.

Adult↗

PubMed1997

Synthesis and biological activity of a 1 alpha,25-dihydroxyvitamin D2 analog bearing an amide group in the side-chain.

Synthesis of a 1 alpha,25-dihydroxyvitamin D2 analog (3), in which the double bond in the side-chain is replaced by an amide group, is described. Condensation of a carboxylic acid (8) with an amine (6) gave an amide (9), which in turn led to 3 via several steps. The analog (3) could not bind to the chick cytosol vitamin D receptor, which indicated the importance of the hydrophobic interaction of the C(22)-C(23) double bond in 1 alpha,25-dihydroxyvitamin D2 (2) with the vitamin D receptor.

Ergocalciferols↗

PubMed1997

Effects of tachykinins on rapidly adapting pulmonary stretch receptors and total lung resistance in anesthetized, artificially ventilated rabbits.

In anesthetized, artificially ventilated rabbits not treated with thiorphan (2 mg/kg), a neutral endopeptidase (NEP) inhibitor, substance P (SP) and neurokinin A (NKA) in doses from 0.2 to 2.7 microg/kg produced dose-related increases in rapidly adapting pulmonary stretch receptor (RAR) activity without any significant changes in total lung resistance (RL), whereas neurokinin B (NKB) at the same concentrations did not significantly alter either RAR activity or RL. In comparison with the excitatory responses of RAR activity to SP and NKA, the magnitudes of increased receptor activity evoked SP were significantly larger than those after NKA administration. The rank order of tachykinins for RAR stimulus potency was SP > NKA > KB. Pretreatment with thiorphan potentiated the increases of RAR activity and RL induced by SP but had no effect on the RAR and RL responses to NKA and NKB. Subsequent administration of L 659, 877 (a selective NK2 receptor antagonist, 2. 3 and 7.6 microg/kg) that dose-dependently inhibited NKA-induced RAR stimulation did not significantly influence augmentation of the RAR and RL responses to SP. Administration of atropine (2 mg/kg, n = 6) in thiorphan-treated rabbits, which had no effect on NKA- and NKB-induced RAR stimuli, significantly attenuated the increases of RAR activity and RL induced by SP. These results suggest that tachykinin-induced RAR stimulation is mediated by the activation of NK2 receptors, probably involving participation of NK1 receptors. Furthermore, potentiation of the increases of RAR activity and RL produced by SP administration in the presence of thiorphan is partly mediated by facilitation of cholinergic neurotransmission.

Animals↗

PubMed1996

Neurosteroidal modulation of social isolation-induced decrease in pentobarbital sleep in mice.

Stressful manipulations are known to change the level of neurosteroids capable of interacting with GABAA receptor in the brain. To clarify the involvement of these neurosteroids in social isolation stress-induced decrease in pentobarbital sleep in mice, we examined the effects of 3 beta-hydroxy-5-pregnen-20-one-3-sulfate (pregnenolone sulfate, PS), a steroidal GABAA antagonist, and 3 alpha,21-dihydroxy-5 alpha-pregnan-20-one (allo-THDOC) and 3 alpha,21-dihydroxy-5 beta-pregnan-20-one (THDOC), positive allosteric modulators of the GABAA receptor, on the hypnotic activity of pentobarbital in socially isolated mice. Pentobarbital (50 mg/kg, i.p.)-induced sleep was significantly shorter in isolated mice than in group-housed mice and adrenalectomy had no effect on the decrease of pentobarbital sleep following social isolation. PS (5-10 mg/kg, i.p. or 12-24 nmol, i.c.v.) decreased pentobarbital sleep in group-housed mice in a dose-dependent manner without affecting the sleep in socially isolated mice. In contrast, allo-THDOC (14.9-37.4 nmol, i.c.v.) and THDOC (5-12.5 mg/kg, i.p. or 14.9-37.4 nmol, i.c.v.) reversed the pentobarbital sleep decreased by social isolation to the level in group-housed mice. These steroids had no effect on the pentobarbital sleep in group-housed mice. Such a reversing effect of THDOC in isolated mice was significantly blocked by PS (24 nmol, i.c.v.). Moreover, i.c.v. injection of yohimbine (30 nmol), methoxamine (200 nmol) and CRF (2.1 nmol) significantly decreased pentobarbital sleep in group-housed mice but not that in isolated mice. The effects of these drugs on pentobarbital sleep in group-housed mice were significantly attenuated by THDOC (12.5 mg/kg, i.p.). These results suggest that changes in the level of neurosteroids with ability to modulate GABAA receptor function are involved in social isolation-induced decrease in the hypnotic activity of pentobarbital in mice.

Adrenalectomy↗

PubMed1996

Effects of cocaine on the rat cerebral commissure.

We investigated the effects of cocaine on the corpus callosum, the nerve fibre bundle that connects the bilateral cerebral hemispheres. Our experiments in rats confirmed that, in the control group, the mid-sagittal area of the corpus callosum in the adult male was significantly larger than this area in the female. Early postnatal exposure to cocaine abolished this sexual dimorphism, that is, cocaine-treated males had a significantly smaller callosal area than the control males. Cocaine induced no significant changes in the weight of the body or brain. There were no significant sex differences in the midline sagittal area of the anterior commissure, and no apparent effects of cocaine exposure were determined in this structure. These findings suggest that early postnatal exposure to cocaine abolishes the sexual differentiation of the corpus callosum in male rats.

Animals↗

PubMed1996

Structural changes in the intramuscular connective tissue during development of bovine semitendinosus muscle.

Structural changes in the intramuscular connective tissue during development of bovine semitendinosus muscle were investigated using the cell-maceration method for scanning electron microscopy, by which cellular elements were eliminated and collagen fibrils and fibres were exposed. The endomysium was discontinuous and showed various shapes and sizes in the muscle of 7-month fetuses. The perimysium consisted of collagen fibres in loose contact with each other. In the muscle of neonatal calves, the endomysium consisted of cylindrical sheaths and displayed a honeycomb structure, and the perimysium was composed of several layers of collagen fibres. Collagen fibrils in the endomysium bound ever more closely with each other, and collagen fibres in the perimysium increased in thickness, and the wavy pattern of collagen fibres became more regular with growth of cattle. We have examined the mechanical strength of the intramuscular connective tissue by our new method, 'intramuscular connective tissue (IMCT) model'. The IMCT model is composed of collagen fibrils and fibres which maintains the organization in the endomysium and perimysium in situ. The shear-force value of the model increased rapidly from the 7th fetal month to the neonatal stage, and increased linearly with postnatal ageing thereafter. Changes in the arrangement of collagen fibrils and fibres seem to closely related to an increase in the mechanical strength of the intramuscular connective tissue during development of bovine skeletal muscle.

Animals↗

PubMed1996

Functional and morphological observations on the microvascular structure of the filiform and fungiform papillae in the cat tongue.

The purpose of this study was to undertake a three-dimensional comparative observation of the microvascular cast specimen (MVCS) of the filiform papillae (FiP) and fungiform papillae (FuP) on the dorsal surface of the cat tongue. By means of the corrosive resin casting technique, the MVCS of the FiP and FuP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). The numerous FiP and FuP distributed sporadically among the different types of the FiP were found on the entire dorsal surface of each cat tongue. A single FiP consisted of a main process (MP) which contained a large spoon-shaped concave network process and the accessory process (AP) contained a bundle of spine-like processes, arranged in a circle at the basal margin of the MP. The FiP can be classified into five types (Type I-V) according to the shape and size of the MP and numbers of the AP. Each FuP consisted of a single MP which contained an ovoid head and many AP surrounding the basal margin of the MP. The FuP can be classified into four types (FuP I-IV) according to the shape and size of the MP and numbers of the AP. The MP of the FuP, a sense organ for taste, of the cat tongue was considered to be a transformed type from the MP of the FiP, which acquires the ability to masticate and swallow functionally.

Animals↗

PubMed1996

The distributive pattern, form and function seen in microvascular cast specimens of filiform papillae on the anterodorsal surface of the adult rat tongue.

The purpose of the present study was to examine in detail the distributive pattern, form and function of small conical papillae (SCP) and of filiform papillae (FIP) in the anterodorsal part of the adult rat fore-tongue in a microvascular cast specimen (MVCS), with the scanning electron microscope (SEM), and to elucidate the close relationship between the morphological characteristics and the function of the tongue. From the results obtained in this study, SCP in the anterior part were subdivided into three types: SCP type I, II and III according to the shape, size, distributive pattern and form taken from the two peripheral sides as for as the median sulcus (MS) in the central portion. The results we obtained suggested that the primary role of SCP types I and II at the apex may be mainly that of touch and attachment to the food and water, while SCP types II and III in the anterior part function efficiently by taking the food and water from both peripheral sides to the MS or central portion, and finally transporting it into the oral cavity and supporting the mastication system.

Animals↗

PubMed1996

Angioarchitectural comparison of the filiform papillae of the cat and rabbit using scanning electron microscopic specimens.

Since the precise reasons for the functional and morphological relationship of the filiform papillae (FP) in microvascular cast specimens (MVCS) between the cat and rabbit tongue are as yet not clear, the functional and morphological characteristics of FP on the anterior dorsal surface of these tongues were studied and compared by scanning electron microscopy (SEM). In both species, numerous FP are usually inclined toward the pharynx. In the cat, in particular, there were five types of FP in which types I-III contained a main process (MP) and many accessory processes (AP), and the concave network aspect of their spoon-like and complex MP faced toward the posterior part of the tongue. In the rabbit, numerous FP showed the same type but without AP. The concave network aspect of their arrow-head-like and loose tips faced in an anterior direction, which was the opposite direction to those in the cat FP. These results suggest that the directional difference in the concave network face of MP on FP in both species i.e., the cat and the rabbit, is due to the difference in feeding habits.

Animals↗

PubMed1996

Angioarchitectural classification of the fungiform papillae in the cat tongue.

Three-dimensional structures of the microvascular network of the fungiform papillae (FuP) of the cat tongue were observed by the corrosion cast method under a scanning electron microscope (SEM). FuP were found to be distributed sporadically among the different types of numerous filiform papillae (FiP). A single FuP consisted of the main process (MP) and the accessory process (AP) which were arranged at-the anterior basal margin of the MP. FuP can be classified into four types (I approximately IV) according to the shape and size of the MP and the number of AP within each FuP. FuP-I to FuP-III contained a large, medium and small MP, showing the small fishnet-ball and oval-ball shapes, and these were surrounded at the anterior basal margin by AP inclining toward the anterior part of the tongue. FuP-IV contained only the small fishnet-ball-shaped MP.

Animals↗

PubMed1996

Death caused by undiagnosed acute pancreatitis.

A fatal case of acute pancreatitis is reported. On account of difficulty in eating caused by persistent dysphagia and heartburn, the clinical condition of a 39-year-old man who had been a heavy drinker deteriorated rapidly. He was taken to a hospital in an ambulance in an unconscious state. Based on the endoscopic examination and blood chemistry data, the diagnosis of hemorrhagic esophagitis and hepatic failure was made. Treatment including fluid infusion was unsuccessful and he died on the second hospital day. Based on a strong suspicion that the pathologic change in the esophagus may have been chemical esophagitis caused by corrosives of some type, the police ordered an administrative autopsy. The postmortem examination revealed marked necrosis in the pancreas and in the abdominal fatty tissue including the omentum and the mesentery. The necrotic areas in the pancreas were accompanied by only a slight degree of hemorrhage. The cause of death was diagnosed as acute pancreatitis. The pathologic change in the esophagus was identified as Candida esophagitis. Alcohol abuse and malnutrition caused by esophagitis were both considered to be factors which lead to the acute fatal pancreatitis.

Acute Disease↗

PubMed1996

Effects of postnatal cocaine on differentiation of the rat corpus callosum.

We investigated the effects of cocaine on the development of the corpus callosum. Pregnant Wistar strain rats (Thirteenth day of gestation) were used in this study. On the day following birth, litters were culled to 8 pups (4 males and 4 females), and rats were assigned to either a control or drug treatment group. From postnatal day 1 (P1, at birth = P0) to P5, cocaine (50 mg/kg) was subcutaneously injected to the cocaine-treated pups, and saline in the same volume to the control pups. Animals were sacrificed in 110 days and a mid-sagittal section of the callosum was obtained. From this section the morphometric measurement of the corpus callosum was performed. In the control group the rat corpus callosum has a sex difference with the male corpus callosum being larger than the female's. But this sex difference disappeared in the cocaine group. This was attributed to the fact that cocaine-treated male rats indicated a significant reduction of callosal area. These findings suggest that the early postnatal cocaine can abolish the sexual differentiation of the corpus callosum.

Animals↗

PubMed1996

Grazing bullet wounds on the tongue and liver.

A 59-year-old man was shot at the wheel of his car while waiting for a traffic light at an intersection. He was shot through the windshield from a distance of about 1 m. He was pronounced dead on arrival at an emergency hospital. X-ray photographs taken there demonstrated the presence of three bullets within the body. The murder weapon was found to be a thirty-eight caliber revolver. In all, five bullet wounds were recognized, one was located in the right side of the neck, one in the lower part of the left temple, and three on the right side of the body. The wound in the right neck was an entrance bullet wound. The bullet had exited at the left temple, after glancing on the root of the tongue. The three wounds on the right side of the body were all entrance bullet wounds. The fatal bullet entered the right chest cavity at the 7th intercostal space and lacerated the right lung and the ascending aorta after glancing on the right lobe of the liver. The cause of death was hemorrhage from the lacerated aorta. The grazing bullet wounds of the tongue and liver were shallow defects of the tissues with irregular margins.

Forensic Medicine↗

PubMed1995

Hyperactivity of central noradrenergic and CRF systems is involved in social isolation-induced decrease in pentobarbital sleep.

The modulatory effects of the central noradrenergic and CRF systems on the pentobarbital-induced hypnotic activity were investigated in socially isolated mice. Pentobarbital-induced sleeping time decreased depending on the duration of isolation period and reached the minimum at 4 weeks after the isolation. The intermale aggressive behavior tested in isolated mice increased along with the decrease of hypnotic activity of pentobarbital. I.c.v. injection of CRF (corticotropin-releasing factor; 0.6-2.1 nmol) and i.p. injection of yohimbine (0.5-1 mg/kg), an alpha 2-adrenoceptor antagonist, significantly decreased the pentobarbital-induced sleeping time in group-housed but not in socially isolated mice while alpha-helical CRF9-41 (alpha hCRF; 3.3-6.5 nmol i.c.v.), a CRF antagonist, and clonidine (12.5-100 micrograms/kg i.p. and 7.5-15 nmol i.c.v.), an alpha 2-adrenoceptor agonist, recovered the hypnotic activity of pentobarbital decreased by social isolation to the level in group-housed mice without changing the activity observed in group-housed animals. alpha hCRF (6.5 nmol i.c.v.) significantly abolished the yohimbine (1 mg/kg i.p.)-induced decrease in the hypnotic activity of pentobarbital in group-housed mice. Propranolol (50-100 nmol i.c.v. and 5-10 mg/kg i.p.), a beta-adrenoceptor antagonist, and prazosin (5-10 nmol i.c.v. and 250-500 micrograms/kg i.p.), an alpha 1-adrenergic antagonist, significantly and dose-dependently recovered the hypnotic activity of pentobarbital in socially isolated mice to the level in group-housed mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic Agents↗

PubMed1995

Noradrenergic denervation attenuates desipramine enhancement of aggressive behavior in isolated mice.

The effects of denervation of central noradrenergic system on the desipramine-induced enhancement of aggressive behavior were examined in long-term isolated mice. Consistent with previous reports, desipramine (10 mg/kg, IP) significantly increased the duration of aggressive behavior in isolated mice. Pretreatment of isolated mice with DSP-4, a selective noradrenaline neurotoxin, significantly attenuated the enhancing effect of desipramine on aggressive behavior without affecting the basal aggressive responses. This effect appeared concomitant with decrease of noradrenaline levels in the cortex, hippocampus, cerebellum and hypothalamus (78%, 75%, 57%, and 17%, respectively). DSP-4 did not significantly affect dopamine or 5-HT levels in these regions. These results suggest that noradrenergic terminals originating mainly from the locus coeruleus play an important role in the desipramine enhancement of aggressive behavior, but not in the basal aggressive behavior of isolated mice.

Aggression↗