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Biomedical subjects

Hiroaki Ohta

Publications and source records attributed to Hiroaki Ohta.

At least 37 records · Page 2Linked to original sources
PubMed2004

Absolute height reduction and percent height ratio of the vertebral body in incident fracture in Japanese women.

Vertebral fractures are the most common complication associated with osteoporosis. The definition of prevalent or incident vertebral fractures is important in epidemiological evaluation and in clinical trials of osteoporosis treatment. There have been few reports regarding the morphometric cutoff criteria for incident fractures in Asians, and only a few reports of their occurrence in Caucasians. The aim of this study was to establish a definition for incident fractures in Japanese women. A total of 279 women, aged 64.8 +/- 9.9 (mean +/- SD) years, were recruited, and repeated thoracolumbar spinal radiographs were performed at a mean of 1.45 +/- 0.44 years after the baseline film. Vertebral fractures were graded from 0 to 3 in both baseline and follow-up films using a semiquantitative assessment by the consensus of three readers. Incident fractures were defined as an increase of grade, except grade 3, and a vertebral body height of less than 12 mm on the baseline film. As morphometric criteria, both absolute height reduction (AHr) and the percent height ratio (PHr) were calculated. Prevalent fractures were observed in 207 vertebrae (6.2%) and 85 cases (30.5%), and incident fractures in 42 vertebrae (1.3%) and 29 cases (10.4%). As morphometric criteria for incident fracture, both a PHr > or =15% and an AHr > or =3 mm or > or =4 mm indicated sensitivity of 49.17% and 50.83% and specificity of 99.92% and 99.90%, respectively. In conclusion, the morphometric criteria of incident fracture combined with a semiquantitative assessment will provide useful information in the study of clinical osteoporosis, especially for international comparisons.

Aged↗
PubMed2004

Uterine cervical diverticulum resembling a degenerated leiomyoma.

BACKGROUND: Uterine diverticulum is a very rare anomaly. Most previously reported cases were called "pregnancy-associated sacculations," and only 2 cases were considered true uterine diverticula. CASE: A 41-year-old woman presented with fever and lower abdominal pain. An extrauterine mass was detected, and a hysterectomy was performed. Pathological examination revealed a cystic uterine diverticulum lined with cervical glands and myometrium arising from the cervix. The final diagnosis was an infected uterine cervical diverticulum. CONCLUSION: Cervical diverticulum is a rare lesion that should be added to the differential diagnosis of a woman presenting with a pelvic mass.

Adult↗
PubMed2004

[Selective estrogen receptor modulator].

SERMs (selective estrogen-receptor modulators) selectively act on various target tissues under estrogen influence as estrogen-agonists or antagonists. Following publication of an interim report from the Women's Health Initiative (WHI) randomized trial, SERMs have drawn considerable attention as agents of interest, in that they allow almost all beneficial effects of estrogen to be retained while at the same time avoiding the harmful side effects associated with HRT. In this regard, raloxifene is reported to act on bone as an estrogen-agonist as does HRT thereby contributing to a significant decrease in the incidence of osteoporotic fractures, while, in contrast, acting on the breast as an estrogen-antagonist unlike HRT to reduce the incidence of breast cancer, and its further role is expected in the treatment of coronary heart disease. Thus, SERMs are emerging as a class of versatile agents with great potential, and their indications are expected to widen with further research evidence.

Female↗
PubMed2004

[Defining the role of raloxifene as a therapeutic agent for postmenopausal osteoporosis: focus on its pharmacological properties].

In this semiar, I propose to describe the pharmacological properties of raloxifene that provide a basis for its role in the treatment of postmenopausal osteoporosis. These pharmacological properties can be described as providing therapeutic benefits in the following three areas: 1) reduction in bone turnover, 2) increases in bone mineral density, and 3) risk reduction in fractures. While reloxifene shares these effects with conventional bisphosphonates that are in common use for postmenopausal osteoporosis, it exerts its antiresorptive effects through a different mechanism of action from those of the bisphosphonates. Furthermore, raloxifene exerts its stimulatory or inhibitory effects on estrogen in a tissue-specific fashion as a selective estrogen-receptor-modulator (SERM), thereby providing a wide range of clinical benefits that result from its ability to exert estrogen-like beneficial effects in tissues other than bone while at the same time inhibiting estrogen-like deleterious effects in other tissues. I therefore propose to define the role of raloxifene as a viable therapeutic option in the treatment of postmenopausal osteoporosis in light of these unique pharmacological features. Current data suggests that raloxifene can be positioned somewhere in between hormone replacement therapy (HRT) and bisphosphonates, and is highly likely to be suitable for use in patients between the ages of 55 and 70, while other agents may be indicated in special populations, such as premenopausal patients, postmenopausal patients with hot flushes, or elderly patients who may be placed at accelerated risk of developing femoral neck fractures. Thus, as a novel therapeutic option with unique clinical benefits, a far greater role may be expected for raloxifene in the treatment of postmenopausal osteoporosis than for other conventional therapeutic agents.

Biomarkers↗
PubMed2004

[Lifestyle management approaches in postmenopausal osteoporosis].

Of the lifestyle management approaches to postmenopausal osteoporosis recommended, encouraging walking appears to be more relevant than ensuring appropriate nutritional intake in preventing bone loss. The focus of the current lecture is therefore on encouraging exercise, as it is not hard to imagine the physical impact of exercise on bone mineral density. As has long been pointed out, in fact, the initial management of postmenopausal osteoporosis consists in subjecting the bone to a continual physical stress, including exercise. In this regard, aerobic exercise including walking has been widely recommended;however, there is no clear evidence showing aerobic exercise to be superior to other kinds of exercise, while several studies reported on the benefit of combining aerobic exercise with pharmacological treatments in postmenopausal women, including our own series. Physical exercise programs or guidelines aimed at the prophylaxis of postmenopausal osteoporosis that draw on research evidence supporting the benefit of encouraging physical exercise need yet to be put in place as a matter of urgency.

Exercise↗
PubMed2003

p54nrb acts as a transcriptional coactivator for activation function 1 of the human androgen receptor.

The androgen receptor (AR) has two transactivation functions that have been mapped to the N- and C-terminal domains and designated as activation function-1 (AF-1) and AF-2, respectively. While the molecular basis for AF-2 function has been well studied, little is known about AF-1 coregulators. Therefore, we attempted to identify AF-1-interacting proteins from HEK293 cells by biochemical purification followed by mass fingerprinting by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Purified AF-1 region-interacting proteins were found to contain nuclear RNA-binding protein p54(nrb), polypyrimidine tract-binding protein-associated splicing factor (PSF), paraspeckle protein 1 (PSP1), and PSP2, which are assumed to be involved in pre-mRNA processing. p54(nrb) interacted with AR via the A/B domain in a ligand-dependent manner. Reflecting the physical interaction between p54(nrb) and the AR A/B domain, AR AF-1 function was potentiated by p54(nrb). Our results suggest that p54(nrb) functions as a coactivator of AR that potentiates transcription, and presumably splicing as well.

Cell Line↗
PubMed2003

One-year spinal bone change in pre- and perimenopausal Japanese women. A prospective observational study.

BACKGROUND: This prospective observational study was designed to determine whether the bone mineral density (BMD) of the lumbar spine decreases before menopause. METHODS: The change in BMD of the second through fourth lumbar vertebrae (delta%L2-4BMD) over the course of 12 months was measured in 197 pre- and perimenopausal Japanese women aged 48.2 +/- 2.3 (mean +/- SD) years. RESULTS: Overall, delta%L2-4BMD decreased significantly, with a greater decrease seen in perimenopausal women. This group also had a significantly higher level of FSH (p < 0.05, t = 7.356), a significantly lower level of estradiol (p < 0.05, t = 4.245), and significantly higher levels of the bone metabolic markers, alkaline phosphatase (p < 0.05, t = 3.841), calcium (p < 0.05, t = 3.939), and osteocalcin (p < 0.05, t = -3.295). Overall, there was a significant positive correlation between osteocalcin and delta%L2-4BMD (r = -0.194, p = 0.0479). CONCLUSION: A subset of perimenopausal women with transient decreases in ovarian function that do not respond to increased FSH may be at increased risk for abnormally low BMD, and may benefit from early management of bone mass.

Adult↗
PubMed2003

Levels of lipoprotein(a) in normal and compromised pregnancy.

OBJECTIVE: To study maternal lipoprotein(a) levels in normal pregnancy and in pregnancy with evidence of vascular disease in the maternal uteroplacental circulation defined by Doppler ultrasound study. SAMPLES: Maternal venous blood was collected from 75 normal pregnant women and 68 pregnant women with evidence of potential uteroplacental vascular disease identified by Doppler ultrasound study. METHODS: Plasma lipoprotein(a) levels in maternal blood were measured using an enzyme-liked immunosorbent assay method. MAIN OUTCOME MEASURES: Plasma lipoprotein(a) levels and pregnancy outcome were examined. RESULTS: None of the normal group had lipoprotein(a) levels greater than 30 mg/dl, a cutoff level which has been associated with increased risk of atherosclerosis. 28 of the 68 women with uteroplacental insufficiency had lipoprotein(a) levels greater than this cutoff level. In this group there was a statistically significant higher prevalence of preeclampsia in comparison with women with a normal lipoprotein(a) level (p < 0.001). The lipoprotein(a) level was significantly higher in severe (n = 13, median 60.5 mg/dl, P < 0.001] than in mild preeclampsia (n = 5, median 34 mg/dl). Those with high levels (> 30 mg/dl) exhibited significantly more adverse indices of fetal outcome. CONCLUSION: This study has demonstrated that high levels of lipoprotein(a) interfere with uteroplacental circulation and play a role in the pathophysiology of preeclampsia. Lipoprotein(a) concentrations are associated with the severity of the disease. We suggest that high levels of lipoprotein(a) might affect the placenta and fetus.

Adult↗
PubMed2003

Early and definitive diagnosis of toxic shock syndrome by detection of marked expansion of T-cell-receptor VBeta2-positive T cells.

We describe two cases of early toxic shock syndrome, caused by the superantigen produced from methicillin-resistant Staphylococcus aureus and diagnosed on the basis of an expansion of T-cell-receptor VBeta2-positive T cells. One case-patient showed atypical symptoms. Our results indicate that diagnostic systems incorporating laboratory techniques are essential for rapid, definitive diagnosis of toxic shock syndrome.

Adult↗
PubMed2003

[A newly opened palliative care ward and the nursing of terminal patients with gynecological cancer at our Department of Obstetrics and Gynecology in Tokyo Women's Medical University Hospital].

Seventy-nine terminal patients with gynecological cancer treated in the past 5 years in our hospital or their families were interviewed on where those patients died and the reason why they chose to die in the place. Fifty-two patients (65.8%) were died at our hospital, 18 patients (22.8%) at other hospitals, 5 (6.3%) at other hospice and 4 (5.1%) at home. The 52 patients who died at our hospital were asked why they chose to die there. 42 of them (80.8%) wanted care at our hospital to the death. 10 (20.2%) had no time to think of home care or other institutions because of the sudden change of the condition. The 18 patients who died at other institutions were also asked about the reason. 9 of them (50%) wanted to die in their hometown or close to their home. 5 of them (27.8%) were referred to other hospitals due to brain metastasis or the necessity of undergoing dialysis. 2 of them (11.1%) were referred to the institutions which provide long-term care. 2 of them (11.1%) were brought into a nearby emergent care hospital and died after the sudden change of the condition. The palliative care ward in our university hospital can provide continued relationship with cancer patients. We had time to talk enough with carcinoma patients and their family in the ward, which widened choices of their death place, including home death.

Attitude to Death↗
PubMed2003

[A newly opened palliative care ward and the nursing of terminal patients with gynecological cancer at our Department of Obstetrics and Gynecology in Tokyo Women's Medical University Hospital].

Seventy-nine terminal patients with gynecological cancer treated in the past 5 years in our hospital or their families were interviewed on where those patients died and the reason why they chose to die in the place. Fifty-two patients (65.8%) died at our hospital, 18 patients (22.8%) at other hospitals, 5 (6.3%) at other hospice and 4 (5.1%) at home. The 52 patients who died at our hospital were asked why they chose to die there. 42 of them (80.8%) wanted care at our hospital to the death. 10 (20.2%) had no time to think of home care or other institutions because of the sudden change of the condition. The 18 patients who died at other institutions were also asked about the reason. 9 of them (50%) wanted to die in their hometown or close to their home. 5 of them (27.8%) were referred to other hospitals due to brain metastasis or the necessity of undergoing dialysis. 2 of them (11.1%) were referred to the institutions which provide long-term care. 2 of them (11.1%) were brought into a nearby emergent care hospital and died after the sudden change of the condition. The palliative care ward in our university hospital can provide continued relationship with cancer patients. We had time to talk enough with carcinoma patients and their family in the ward, which widened choices of their death place, including home death.

Attitude to Death↗
PubMed2003

[Sex differences over time in bone development and maintenance and their mechanisms].

There is a clear, sex-related difference in speed of bone development in favor of female infants over that of females infants, with an excess of estrogen secretion at this stage likely accounting for the difference. In this, females appear to benefit by their high level of estrogen secretion which is three times that in males. However, males are less susceptible to a drastic change in bone density even at a greater age, as they are able to develop and maintain bone mass with a much lower but constant level of estrogen than that required in females. In contrast, females undergo a drastic change in estrogen levels after menopause and are hardly able to arrest bone resorption, thus suffering a steep fall in bone mass. Thus, there is also a clear difference in bone development and maintenance over time between sexes, the reason likely being a drastic rise or fall in estrogen levels over time.

English Abstract↗
PubMed2002

Bone resorption versus estrogen loss following oophorectomy and menopause.

OBJECTIVES: To investigate if menopause and oophorectomy may represent different risk factors for bone resorption/loss. METHODS: The urinary levels of pyridinoline (Pyr) and deoxypyridinoline (D-pyr), the serum levels of type I carboxy-terminal pyridinoline cross-linked telopeptide (ICTP), and lumbar bone mineral density (BMD), were compared in 80 Japanese women after menopause or oophorectomy. These women were divided into four groups of 20 women each as follows: early postmenopausal stage (early physiologic menopause < 3 years before study entry); late postmenopausal stage (physiologic menopause > or = 3 years before study entry); early postoophorectomy stage (oophorectomy < or = 03 years before study entry); or late oophorectomy stage (oophorectomy > 3 years before study entry). RESULTS: Lumbar BMD was significantly lower in the late groups compared to their respective early groups and was lowest in the late postoophorectomy group. The ratio of D-pyr/creatinine (Cr) was not significantly different among the four groups. The ratio of Pyr/Cr was significantly higher in the early postoophorectomy subjects compared with either late group. The serum level of ICTP was significantly higher in the early postoophorectomy group compared to all other groups. CONCLUSIONS: These findings suggest that serum ICTP may be useful in detecting changes in bone resorption after oophorectomy and that women are at greater risk for bone resorption after oophorectomy than after physiologic menopause, although this difference appears to diminish with time.

Amino Acids↗
PubMed2002

A case of pregnancy with a history of paradoxical brain embolism.

Brain embolisms in younger persons are rare but are often caused by a paradoxical embolism, the embolic entry of a venous thrombus into the systemic circulation through a right-to-left shunt. A 27-year-old pregnant woman presented with hemiplegia that had been treated with an antiplatelet agent since the occurrence of a paradoxical brain embolism via the pulmonary arteriovenous fistula. A tendency of hypercoagulation is generally observed during pregnancy, so a patient with this condition has a strong risk factor for venous thromboembolism during pregnancy and even more so for arterial thromboembolism under the intense strain of labor, which is much stronger than that of the Valsalva maneuver. This case had been controlled well with an antiplatelet agent and an anticoagulant while the levels of coagulation and fibrinolytic factors were monitored and was followed by a successful pregnancy outcome.

Adult↗