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Biomedical subjects

H Azuma

Publications and source records attributed to H Azuma.

At least 271 records · Page 15Linked to original sources
PubMed1985

[The natural course of osteoarthritis of the hip. Indication of conservative treatment in relation to osteophyte formation at the acetabular rim].

One hundred and eighty-five hips from 152 patients with primary or secondary osteoarthritis were studied in an attempt to assess the degrees of hip pain in contrast to radiological and other clinical findings. In 30.8% and 26.4% of the primary and secondary osteoarthritic hips respectively, hip pain showed some gradual decrease as time elapsed. Pain relief probably in association with osteophyte formation at the craniolateral acetabular rim occurred in 62.5% and 33.3% of the primary and secondary osteoarthritic hips respectively. Significant parameters observed in the primary osteoarthritic cases of the decreasing pain group were as follows: A lesser extent of cranial displacement of the femoral head, poor capital drop development, well developed floor osteophyte. On the other hand significant parameters in the decreasing pain group of secondary osteoarthritis were as follows: Well developed floor osteophyte, a small size of cyst in both the femoral head and the acetabulum, few "b" or "d" type of bony sclerosis in the acetabulum. Careful observation of radiographic changes (cyst and sourcil) would be most important, especially in secondary osteoarthritis, to decide the indication of surgery. On the basis of histological studies of osteophyte at the craniolateral acetabular rim obtained at the operation, it was assumed that the osteophyte formation had initiated from metaplasia of the labrum or synovial membrane and progressed by a form of chondral ossification after the process of fibrous tissue formation. A well developed trabecular density in the osteophyte at the craniolateral acetabular rim was determined by the use of Muto digigrammer system, Model G-002.

Acetabulum↗
PubMed1984

Potentiation of antiaggregating activity of adenosine by a phosphodiesterase inhibitor, EG626 (oxagrelate), in human platelets in vitro.

EG626 (oxagrelate), a specific inhibitor of cyclic AMP phosphodiesterase, produced in vitro a concentration-dependent inhibition of platelet aggregation induced by collagen and ADP in human platelets. When adenosine was added to the platelet rich plasma (PRP) in the presence of a threshold concentration of EG626, the potency of adenosine in inhibiting platelet aggregation was markedly potentiated. This potentiating effect of EG626 proved to be synergistic, but not additive and was accompanied by a marked accumulation of cyclic AMP in the platelets. The antiaggregating and cyclic AMP increasing activities of adenosine were little affected by S-(p-nitrobenzyl)-6-thioguanosine (6TG), an uptake inhibitor of adenosine, or 2'-deoxycoformycin, an inhibitor of adenosine deaminase. The incorporation of adenosine into platelets was abolished by 6TG. These observations indicate that incorporation of adenosine into platelets is not required for inhibition of aggregation or an increase in cyclic AMP and that the site of action of adenosine is probably extracellular. It also appears that the synergistic action by EG626 is not the result of an inhibition of adenosine uptake and/or adenosine deaminase. This speculation is supported in part by the finding that EG626 also potentiates the antiaggregating activity of 2-chloroadenosine. Antiaggregating activity of prostaglandin E1, an activator of adenylate cyclase, was markedly potentiated in combination with EG626. Dibutyryl cyclic AMP showed a time-dependent inhibition of the platelet aggregation, and the inhibitory action was markedly potentiated by EG626. Qualitatively similar results were obtained with another phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX). All these data suggest that the synergistic potentiation of the antiaggregating activity of adenosine by EG626 might be due to the synergistic accumulation of cyclic AMP in the platelets. This action is mediated through activation of adenylate cyclase by adenosine in combination with the inhibition of cyclic AMP phosphodiesterase by EG626.

1-Methyl-3-isobutylxanthine↗
PubMed1984

Trabecular microfractures in the acetabulum. Histologic studies in cadavers.

The distribution of trabecular microfractures was studied in 39 cadaveric acetabula. The mean age of the group with microfractures was 71 years and the mean age of the group without fractures was 60 years. Most of the microfractures were located at the subchondral, weight-bearing portion of the acetabulum. Our observations suggest that trabecular microfractures are involved in the formation of bone cysts.

Acetabulum↗
PubMed1984

[Growth of the human acetabulum--with a comparison of cartilaginous proliferation in acetabular and triradiate physeal cartilages].

For the purpose of investigation on the human acetabular growth, proliferation of cartilage cells as well as extent and degree of maturation of newly formed trabeculae in both acetabular and triradiate physeal plates were observed. The material consisted of 13 acetabula of the left hip joints from necropsies whose age distribution ranged from the period of neonate to adolescence. The acetabulum was divided into 5 parts by radial lines. Histological sections were then prepared from each of these parts. The growth of the acetabulum was mainly based on the development of the acetabular and triradiate physeal cartilages, and it seemed that the course of newly formed trabeculae from both physeal plates showed centripetally directed arrangement, with convergence upon a point. These trabecular arrangement was most conspicuous in the neonatal period in which active new bone formation progressed. Based on these findings it would be reasonable to consider that the acetabular physeal cartilage takes a large part of increase in depth of the acetabulum, while the triradiate one is mainly responsible for increase in its diameter. From neonatal period to about 1 year of age there was an active growth of both acetabular and triradiate cartilages. With age the growth rate of physeal plates showed a decrease, and there was a tendency to a predominance of triradiate cartilage proliferation over acetabular one. On reaching adolescence cessation of cartilage growth occurred in both physeal plates.

Acetabulum↗
PubMed1984

[Distribution of trabecular microfractures in the proximal femur--with the epiphyseal scar as a landmark].

The distribution of the trabecular microfractures in normal human proximal femora was investigated to see whether they were related to the femoral neck fracture of the elderly. In this study the epiphyseal scar was employed as an anatomical landmark in the proximal femur, since the authors' observation suggested that it remained throughout life and was located in constant connection with the margin of the articular cartilage. The medial aspect of the proximal femur was divided into three anatomical zones, which were called epiphyseal, subepiphyseal and subcapital ones, respectively. There were two areas in which trabecular microfractures concentrated; one was about the lateral end of the epiphyseal scar and another the subepiphyseal zone. Few microfractures were noted on the principal compressive trabeculae. A femoral neck fracture of the elderly usually provides a fracture line running from the lateral end of the epiphyseal scar down to the subcapital zone. Thus the fracture takes place just within the area of concentration of trabecular microfractures laterally, whereas it passes caudad to the medial group of microfractures. The authors hypothesize that the trabecular microfractures arising about the lateral end of the epiphyseal scar may have an etiological significance for the femoral neck fracture, in contrast that those in the subepiphyseal zone may not.

Adult↗
PubMed1983

Pharmacological properties of platelet strips.

The pharmacological properties of human platelet strips were studied by recording changes in tension after the application of various compounds. The platelet strips were prepared by packing cold re-calcified human platelets over a sheer gelatinized nylon mesh. The contractile response of such a strip was dependent on the number of platelets sticking to the nylon mesh. The strip was contracted by the addition of platelet aggregation inducers such as ADP, norepinephrine, thrombin and collagen, thereby suggesting that the contractile response is mediated through membrane receptors on the platelets. The ED50 values of the aggregation agents which contracted the strip were much the same as those which induced platelet aggregation, thereby suggesting that contraction of the platelet strip is similar to platelet aggregation in platelet rich plasma (PRP). The addition of platelet aggregation inhibitors such as papaverine, W-7 and PGE1 relaxed the platelet strip. The ED50 values of the aggregation inhibitors which relaxed the platelet strip were also similar to those for platelet aggregation inhibition. The time course of the release of the preloaded [14C]serotonin from the platelet strips correlated well with that of the tension developed.

Adenosine Diphosphate↗
PubMed1983

A new anatomic classification of capital fragments in femoral neck fractures with the epiphyseal scar as a guide.

Seventy femoral neck fractures were examined clinically, radiologically, and histologically to ascertain whether the shape of the capital fragment, irrespective of the nature or age of the fracture, could be a determinant of the biologic condition within the head. Three types of excised capital fragments were defined according to the anatomic location of the fracture surface, with particular reference to the epiphyseal scar. Type I fragments, in which the fracture surface lies along the epiphyseal scar, showed complete capital necrosis, whereas Types II and III fragments, with the fracture surface in the subepiphyseal and subcapital zones, respectively, were found to be histologically viable. Moreover, Type III specimens tended to be more abundant in biologic response than Type II specimens. Thus, the biologic condition of the capital fragment is closely related to its shape. Since the type of capital fragment is, in most cases, judged correctly on the preoperative roentgenogram, this classification can be a helpful clue to the choice of treatment. From the biologic point of view, osteosynthesis should be limited to fractures with Type III capital fragments. The authors also hypothesize that the fractured femoral head, if untreated, may decrease in size and, therefore, in vascularity during the postfracture course.

Adolescent↗
PubMed1982

Contents and compositions of glycosaminoglycans in different sites of the human hip joint cartilage.

The distribution of glycosaminoglycans (GAGs) in different functional regions (weight-bearing and nonweight-bearing portions) of the human hip joint cartilage was studied. The results obtained were as follows: (1) Weight-bearing cartilage contains larger amounts of GAGs than nonweight-bearing, cartilage. (2) Weight-bearing cartilage contains keratan sulphate in higher ratio to chondroitin sulphate than nonweight-bearing cartilage. (3) The differences in content and composition of GAGs between the weight-bearing and nonweight-bearing portions are more pronounced in the femoral head than in the acetabulum. The preliminary analyses showed that the chondroitin sulphate from the acetabular cartilage contained exclusively 6-sulphated disaccharide units and there was some heterogeneity in keratan sulphate.

Acetabulum↗
PubMed1982

Effects of 7-ethoxycarbonyl-6,8-dimethyl-4-hydroxymethyl-1(2H)-phthalazinone (EG626) on the spinal trigeminal nucleus, ventral posteromedial nucleus, and sensory cortex.

Effects of 7-ethoxycarbonyl-6,8-dimethyl-4-hydroxymethyl-1 (2H)-phthalazinone (EG626) on the spinal trigeminal nucleus (STN), ventral posteromedial nucleus (VPM), and sensory cortex were examined in cats anesthetized with alpha-chloralose in comparison with the effects of morphine. EG626 produced a dose-dependent inhibition of the polysynaptic components of the cortical field potentials upon VPM stimulation and either facilitatory or inhibitory effects on the polysynaptic components of the VPM field potential upon stimulation of the medial lemniscus, while the drug failed to affect the STN field potential with trigeminal nerve stimulation. Morphine inhibited the postsynaptic components of the STN field potentials and to a lesser extent, the polysynaptic components of the cortical field potential; and the effects of morphine on the VPM field potential were similar to those seen with EG626. Pretreatment of the animal with naloxone antagonized the facilitatory effect on the VPM field potentials produced by morphine, but not those by EG626. Morphine and EG626 induced either a prolonged increase in the blood flow or transient increase followed by a decrease in the blood flow in the VPM. These results suggest that EG626 may impair the polysynaptic transmission and/or neuron excitability in the sensory cortex and the VPM at least partly due to the change in blood flow there as does morphine. Unlike morphine, however, EG626 did not produce any obvious effect on the STN.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1982

[Suppressive effects of lisuride on the synthesis, release and metabolism of dopamine in rat brain].

Effects of lisuride, a central dopaminergic agonist of the ergot type, on the biosynthesis, release and metabolism of dopamine at the dopaminergic nerve terminals of the rat brain were studied under several experimental conditions. 1) In the rat whose impulse flow of dopamine neurons and the activity of aromatic amino acid decarboxylase were inhibited by the pretreatment with gamma-butyrolactone and with 3-hydroxybenzylhydrazine (NDS 1015), respectively, DOPA formation in the neostriatum and limbic forebrain were decreased significantly by the s.c. administration of lisuride at the dosage known to be ineffective on the postsynaptic dopamine receptor. 2) When it was measured by the accumulation of 3-methoxytyramine in the neostriatum and limbic forebrain of pargyline (MAO inhibitor)-pretreated rats, lisuride at the low dosage caused the inhibition of not only the spontaneous release of dopamine from the nerve terminal to the synaptic cleft, but also the release induced with methamphetamine. 3) In the rat whose dopamine biosynthesis was inhibited with alpha-methyl-p-tyrosine, lisuride caused the suppression of dopamine metabolism, resulting in significant increases of dopamine histofluorescence in the nucleus caudatus, olfactory tubercle and median eminence. As to the effect on dopamine histofluorescence, apomorphine at 1 mg/kg was equipotent to lisuride at 50 micrograms/kg. It was concluded from these results that lisuride administered at low dosage interacts preferentially with the presynaptic dopamine receptor, hereby causing the suppressive effects on the tyrosine hydroxylase reaction and the dopamine release mechanism in the dopamine nerve terminals of the brain.

Animals↗
PubMed1982

[Effects of an ergot derivative, lisuride, on the central nervous system -- stimulatory effect on local cerebral glucose utilization in the rat].

Effects of lisuride, a central dopamine and serotonin agonist of the ergot type, on local cerebral glucose utilization were studied in conscious, anesthetized, and substantia nigra-lesioned rats using the autoradiographic 2-deoxyglucose method. In the conscious rat, lisuride produced dose-dependent (0.05-0.5 mg/kg s.c.) increases of glucose utilization in the cerebellar gray structures (lobule of culmen, vermian lobule, uvula, cerebellar hemisphere) and the lateral nucleus of the thalamus. Although some other gray structures including cerebral cortex were also slightly stimulated, no change was observe in the hippocampus, hypothalamus, amygdala, mammillary body, superior colliculus, pons, and any of the white structure. The stimulatory effect of lisuride was abolished almost completely by the pretreatment with sulpiride or haloperidol. Pentobarbital and gamma-butyrolactone produced marked reduction in the glucose utilization all over the brain, and these effects were not affected by the pretreatment of lisuride. A unilateral 6-hydroxydopamine lesion at the substantia nigra caused a reduction of glucose utilization in the ipsilateral auditory cortex that was reversed by the administration of lisuride. These results indicate that lisuride modulates the motion coordination function of the cerebellum through the cerebral cortex.

4-Butyrolactone↗
PubMed1982

[Changes of the femoral head in intracapsular fractures of the femoral neck---with special reference to old fracture cases].

Coronal slab sections of 78 femoral heads removed from patients with fractures of the proximal end of the femur were examined by radiographical and histological methods and a classification of fracture types based on the epiphysial scar holding an anatomical landmark was presented. The transepiphysial type (type I) showed total necrosis, and in the subepiphysial type (type II) some new bone formation was found at the "subepiphysial" zone, though no such reactive changes were seen in most parts of the specimens. Although necrosis was observed in different degrees and extent in the subcapital type (type III), some reactive new bone formation was always observed in the vicinity of the fracture surface. In the type III which was most frequent, viabilities of the trabeculae were examined in cases of fresh and old fractures (over one month after fractures), with or without internal fixation in old cases. It was then found that bone viabilities were remarkable in the fresh head than the old, and the head excised for failed internal fixation proved to be more viable than the head for primary insertion of a prosthesis. In about a half to one third of the type III the inferior metaphysial vessels were spared. Considering the types of fractures with post-fracture course, the initial type III may be changed into types I, II or III and the initial type II can remain as it is or be transformed into type I.

Adult↗