Search PubMed⌕ Search

Biomedical subjects

R Ueno

Publications and source records attributed to R Ueno.

At least 55 records · Page 3Linked to original sources
PubMed1988

Cervical spondylotic myelopathy in the aged patient. A radiographic evaluation of the aging changes in the cervical spine and etiologic factors of myelopathy.

Cervical spondylotic myelopathy among older individuals was investigated radiographically in 42 patients over age 60 years, and compared with those of younger patients. The cervical spine in the aged patients displayed dynamic canal stenosis in addition to static canal stenosis based on the aging process. Myelography and computed tomography-myelography showed multisegmental lesions (average: 3.0 lesions), that contributed to the various clinical features of myelopathy. The upper disc levels of C3-4 and C4-5 had a tendency to be involved in the aged patients, and the spinal cords were extensively compressed as compared with the younger patients. Disc protrusion, posterior osteophyte, and retrolisthesis, in addition to ligamentous entrapments were the primary etiologic factors of myelopathy. Morphologically, the high prevalence of cord atrophy was seen on computed tomography-myelography in the aged patients. This indicated severe pathologic changes in the cervical spinal cord, and its prognosis was considered to be poor.

Aged↗
PubMed1987

[Etiologic factors of cervical spondylotic myelopathy in aged patients--clinical and radiological studies].

Thirty-seven aged patients with cervical spondylotic myelopathy were investigated clinically and radiologically, and their findings were compared with those of younger patients. Dynamic canal stenosis in addition to developmental canal stenosis had a significant role in the occurrence of myelopathy in the aged patients. This dynamic canal stenosis was commonly encountered in the upper disc levels of C3-4 and C4-5. Myelography and CT-metrizamide myelography represented multisegmental lesions which resulted in variable clinical features. Spinal cord compression was correlated with severity of symptoms (p less than 0.05) and was more extensive in the elderly than in the younger patients. Furthermore, morphological changes of spinal cord were classified into four types: central, lateral, diffuse and additionally atrophic types. The high prevalence of diffuse type (51.4%) and atrophic type (21.6%) in the aged patients suggested that the prognosis despite treatment might be poor.

Aged↗
PubMed1987

Etiologic factors of myelopathy. A radiographic evaluation of the aging changes in the cervical spine.

The radiographic characteristics of the cervical spine among older individuals were investigated in 100 normal subjects and compared with those of younger subjects. The cervical spine of the older subjects displayed narrowing of intervertebral discs and osteophytoses (posterior osteophytes as well as anterior osteophytes) at the levels of C5-6 and C6-7, where the range of motion was decreased. Such degenerative changes resulted in vertebrolisthesis, especially retrolisthesis, predominantly at the levels of C3-4 and C4-5, where intervertebral disc space was well maintained and mobility was well preserved. Both static and dynamic anteroposterior canal diameter decreased with age. Throughout the aging process the dynamic canal became much narrower than the static canal, except at C2-3. Posterior osteophytes at C5-6 or C6-7 and retrolisthesis at C3-4 or C4-5 were major levels of stenosis associated with changes in the dynamic canal. Following the same evaluation system, 20 elderly patients with cervical spondylotic myelopathy were assessed. Based on the above-noted characteristics of the aging process, patients with myelopathy had smaller static and dynamic canal measurements than normal subjects. The development of cervical myelopathy, however, was not always based on critical static or dynamic canal stenosis (10% in this series) and might involve other factors.

Aged↗
PubMed1986

Alterations in nociception after intracisternal administration of prostaglandin D2, E2 or F2 alpha to conscious mice.

The effect of intracisternal administration of three major prostaglandins on nociceptive responses was evaluated in mice. Prostaglandin D2 had biphasic effects on pain thresholds (hot plate and acetic acid writhing tests) when given in a dosage range of 5 ng to 5 micrograms per mouse. Lower doses of prostaglandin D2 (less than or equal to 15 ng) increased the sensitivity to pain stimulation. Higher doses (greater than or equal to 50 ng) caused hypoalgesia, which was completely blocked by intracisternal injection of 500 pg of naloxone. Prostaglandin E2 (5 ng-5 micrograms) also had a biphasic effect on pain thresholds, similar to the effect of prostaglandin D2. However, the hypoalgesia caused by a higher dose of prostaglandin E2 (5 micrograms) was not blocked at all by naloxone doses of up to 500 ng. Prostaglandin F2 alpha had little effect on pain thresholds. These results indicate that each prostaglandin has a specific effect on the modulation of nociception.

Animals↗
PubMed1986

Prostaglandin E2, a seminal constituent, facilitates the replication of acquired immune deficiency syndrome virus in vitro.

Acquired immune deficiency syndrome (AIDS)-associated virus is thought to be transmitted effectively through semen during sexual activities from male to male or from male to female. Prostaglandin (PG) E2 is one of the immunosuppressive compounds present in high concentrations in human semen. We, therefore, investigated direct effects of PGE2 and other PGs on AIDS-associated virus infection and replication in vitro. First, type III human T-lymphotropic virus (HTLV-III) was used to infect a T-cell line (MT-4) in culture. PGE2 (10 nM to 10 microM) added to the culture medium enhanced the production of infectious virus in a dose-dependent fashion. In the presence of 5 microM PGE2, 2.5-fold more virus were released from the infected MT-4 cells as compared to untreated control cells on day 3 after infection. Second, when we used an HTLV-III continuous-producer cell line (Molt-4/HTLV-III), PGE2 and PGD2 added to the culture medium increased the number of viruses released from Molt-4/HTLV-III cells. Other PGs such as PGF2 alpha and 13,14-dihydro-15-keto PGE2 did not affect the replication of HTLV-III in this system. These results indicate that some PGs including seminal PGs enhance the AIDS-associated virus replication in vitro. We propose that PGE2 in human semen might directly facilitate the infection of AIDS-associated virus and cause the efficient transmission of the virus during sexual activities.

Cell Transformation, Viral↗
PubMed1986

Prostaglandin E2 administered via anus causes immunosuppression in male but not female rats: a possible pathogenesis of acquired immune deficiency syndrome in homosexual males.

To explain a possible pathogenesis of acquired immune deficiency syndrome (AIDS) in homosexual males, we propose the following hypothesis. Prostaglandin E2 in human semen given via anus during anal intercourse may cause an immune dysregulation in the male semen recipients; this immunosuppressive effect of prostaglandin E2 may be one of the underlying factors that stimulate AIDS-associated virus infection or that trigger the latent AIDS-associated virus. This hypothesis is supported by the following experimental results. Anal infusion of prostaglandin E2 or D2 into male rats reduced in vitro responses of T lymphocytes to phytohemagglutinin. However, the T-cell response of female rats was not reduced significantly by the anal infusion of seminal prostaglandins.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Prostaglandin synthesizing enzyme activities of hepatocytes and non-hepatocytes in rat liver as a function of age.

The developmental profile of prostaglandin (PG)-synthesizing enzymes in liver was investigated in rats from the fetus to 2 years old. In the neonatal period, the activities of PGD2-(2.7 nmol/min/mg protein) and PGE2-(2.2 nmol/min/mg protein) synthesizing enzymes were predominant, whereas PGE2-synthesizing enzyme alone further increased in activity during adult to old ages (5.2-6.1 nmol/min/mg protein). In order to determine the sites of PGs production in rat liver, we prepared hepatocytes and non-hepatocytes by a collagenase digestion method. Regardless of the ages we examined, the major PG produced in the hepatocytes was proved to be PGE2, on the other hand, PGD2 was almost exclusively produced in the non-hepatocytes. These results suggest that each PG may have individual roles in the development of rat liver.

Aging↗
PubMed1985

Flash photolysis studies on the CO complexes of ferrous cytochrome P-450scc and cytochrome P-45011 beta. Effects of steroid binding on the photochemical and ligand binding properties.

Upon irradiation by a light flash (100-J), the carbon monoxide complex of cytochrome P-450scc was fully photodissociated in both the presence and absence of cholesterol, while less than 20% of the CO complex was photodissociable with those of deoxycorticosterone-bound and -free forms of cytochrome P-45011 beta. When the quantum yield of the reaction was measured for each photodissociable portion, the values were 0.5 and 1.0 for the substrate-free and -bound forms of cytochrome P-450scc, and 0.03 and 0.8 for the substrate-free and -bound forms of cytochrome P-45011 beta, respectively. Thus, CO complexes of these enzymes become more photosensitive upon binding with the specific substrates. Steroid binding also affected kinetic constants of reactions between the ferrous enzymes and CO. The rate constants for the CO recombination at 15 degrees C were 2.7 X 10(6) and 2.3 X 10(5) M-1 s-1 for the substrate-free and -bound forms of cytochrome P-450scc, and were 7.0 X 10(5) and 5.4 X 10(3) M-1 s-1 for the substrate-free and -bound forms of cytochrome P-45011 beta, respectively. The rate constants for the CO dissociation also decreased upon the steroid bindings. The products of the enzyme reactions, pregnenolone and corticosterone, had similar effects on the kinetic constants. From these findings, we postulate that the binding of a steroid to the substrate site of each enzyme alters the bonding character of CO with the heme-iron, thereby affecting both photochemical and kinetic properties of the CO complex. The nature of the photoindissociable portion of the CO complex of cytochrome P-45011 beta is also discussed.

Adrenal Cortex↗