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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 19 recordsLinked to original sources
PubMed2006

Medroxyprogesterone acetate stimulates cdk inhibitors, p21 and p27, in endometrial carcinoma cells transfected with progesterone receptor-B cDNA.

PURPOSE OF INVESTIGATION: Progestin is reported to suppress the growth of endometrial carcinomas, although its precise mechanism of action is not clear. This study aimed to transfect progesterone receptor-B (PRB) cDNA into endometrial carcinoma cells and investigate the effect of medroxyprogesterone acetate (MPA) on cell growth, and p21 and p27 expression in the transfectant. METHODS: Immunoblotting for p21 and p27 was performed at predetermined times after the administration of MPA. RESULTS: PR expression was maximally induced in Ishikawa cells at 24 hrs after the transfection. At 1 x 10(-6) M, MPA suppressed the growth of the transfectant by 34% on day 6 and stimulated p21 accumulation at 48 to 72 hrs and p27 accumulation at 48 to 96 hrs after its administration. PRB cDNA was effectively transfected and in the transfectant MPA at 1 x 10(-6) M, the dosage suppressing growth, induced p21 and p27expression. CONCLUSION: p21 and p27 may be related to progesterone-induced growth suppression in human endometrial adenocarcinoma.

Blotting, Western↗
PubMed2006

[Aortic valve replacement in elderly patients with small aortic annulus; is the indexed effective orifice area important?].

We sought to determine whether the small indexed effective orifice area (EOAI) increased mortality and morbidity after aortic valve replacement (AVR) in patients over 75 years of age. From May 1999 to July 2005, 77 patients underwent isolated AVR for aortic stenosis. They were divided into 3 groups (S-EOAI : EOAI < or = 0.7 cm2/m2, M-EOAI : 0.7 cm2/m2 <EOAI < or = 0.85 cm2/ m2, L-EOAI : 0.85cm2/m2 <EOAI) for evaluation. We examined the body surface area (BSA), EOAI, and the left ventricular (LV) mass index (LVMI). We found that patients with S-EOAI had less symptomatic improvement (p <0.05, vs L-EOAI) and LV mass regression (p< 0.01, vs L-EOAI). But, their average New York Heart Association (NYHA) class was improved significantly (2.3 +/- 0.8 vs 1.8 +/- 0.7 : preoperative vs postoperative, p=0.001). Furthermore, severe patient-prosthesis mismatch (PPM) had no significant negative impacts on the freedom of valve-related complications (75.1% : S-EOAI group vs 92.0% : L-EOAI group) and the 5-year survival (84.9% : S-EOAI group vs 87.8% : L-EOAI group). In elderly patients, the average NYHA class was 1.9 +/- 0.6 postoperatively (p<0.0001 vs preoperative) and the LVMI showed significant regression (p<0.0001) despite an average EOAI of 0.73 +/- 0.13 cm2/m2. It is important to consider whether the benefits of avoiding PPM overcome the drawbacks of other complicated techniques. In this study, we found that moderate PPM (0.7 cm2/m2 < or = EOAI) is acceptable to elderly patients.

Aged↗
PubMed2006

[Evaluation of aortic valve replacement involving small severely calcified aortic annulus in elderly patients].

We performed aortic valve replacement in 24 patients aged over 70 with small calcified valves. The surgical management of such patients remains controversial as the extensive calcification compromises implantation. Hence, we used an ultrasonic debridement instrument to remove calcium and selected a small prosthesis with the largest possible orifice without enlargement of the aortic annulus. Echocardiography showed significant reductions in left ventricular mass index compared with preoperative values. Early and mid-term prognosis has been relatively good.

Aged↗
PubMed2006

Angiopoietin-1, 2 and Tie2 expressions in endometrial adenocarcinoma--the Ang2 dominant balance up-regulates tumor angiogenesis in the presence of VEGF.

We investigated Ang1, Ang2 and Tie2 expressions including balance and intratumoral vessels in the role of angiogenesis of endometrial adenocarcinoma. Immunohistochemical staining was performed on 133 patients with endometrial (endometrioid) adenocarcinoma, including 73 with G1, 34 with G2, and 26 with G3. The levels of Ang1, Ang2 and Tie2 expressions were expressed as staining score. Total vessel count (TVC), microvessel count (MVC) and mean vessel diameter (VD) in the CD34-stained tissues were measured in five hot spot areas at x 200 magnification by image cytometry. These results were compared with high and low vascular endothelial growth factor (VEGF) expressions. Ang1, Ang2, Tie2 and CD34 were expressed in the cytoplasm of tumor cells. A significant correlation was found among Ang1, Ang2 and Tie2 expressions. In high VEGF cases, Ang1 expression was correlated negatively with TVC and MVC, but positively with VD, and the Angl < Ang2 group was significantly higher in TVC and MVC and tended to be smaller in VD than the Ang1 > Ang2 group. VD was significantly larger in G3 than in G1. The Ang1 < Ang2 balance may be one of the key factors for angiogenesis of endometrial carcinoma in the presence of high VEGF expression.

Adenocarcinoma↗
PubMed2006

[Effects of additional pulmonary blood flow after bidirectional Glenn procedure].

Thirteen cases of functional single ventricle who had undergone bidirectional Glenn procedure were divided into 2 groups according to presence (5) or absence (8) of additional pulmonary blood flow. Additional flow was preserved in cases with relatively small pulmonary artery index (PA index), and their sources were antegrade pulmonary blood flow (2), and Blalock-Taussig (BT) shunt (3). In the control group, PA index was reduced to about 70% of the preoperative value, while in the additional group, pulmonary artery growth was recognized without significant elevation of mean pulmonary artery pressure. However, atrioventricular valve regurgitation progressed and systemic ventricular volume did not decrease after Glenn in the additional group. Therefore special consideration for the timing of Fontan procedure is mandatory.

Anastomosis, Surgical↗
PubMed2006

[Effects of octreotide acetate on intractable chylothorax after surgery for congenital heart diseases].

We experienced 2 infants in whom octreotide acetate was effective on intractable chylothorax after surgery for congenital heart diseases. They were 8- and 5-month-old. They were diagnosed as having corrected transposition of the great arteries (TGA) and tetralogy of Fallot respectively, and underwent bidirectional Glenn anastomosis and right modified Blalock Taussig shunt. Chylothorax was revealed on the 11th and the 1st postoperative day, and was not improved by any conventional therapy in either case. Then octreotide acetate was infused continuously with 0.1-0.6 micorg/kg/hour for 24 and 7 days. Chylothorax disappeared completely without any complications such as disturbance of blood sugar level or growth retardation. Octreotide acetate was effective and safe even in infants in intractable chylothorax after surgery for congenital heart diseases, as long as used for short period.

Cardiac Surgical Procedures↗
PubMed2006

[Effects of dexmedetomidine hydrochloride on postoperative sedation in cardiovascular surgery].

BACKGROUND: Postoperative assessment of brain damage in cardiovascular surgery is often obscured by sedatives. Therefore, early postoperative detection of brain attack and its treatment are also hampered. A newly approved sedative, dexmedetomidine hydrochloride has weak analgesic effect and no respiratory depressive effect. These characteristics allow early assessment of brain damage after surgery. In this report, we compared 2 sedatives, propofol and dexmedetomidine hydrochloride, in cardiovascular settings. SUBJECT AND METHODS: Both sedatives were initiated right after admission to the intensive care unit (ICU), followed by titrimetric method targeting for the sedation agitation scale (SAS) from 1 to 4. Thirty-five cases were included in dexmedetomidine hydrochloride group (DEX group) and 16 cases were included in propofol group (Prop group). RESULTS: Preoperative and operative demographic data were the same between the 2 groups. Conversion rate to another sedatives, and incidence of vasopressor or hypotensor use were both in the same proportion in both groups. Intubated time was the same in both groups. Both systolic and diastolic blood pressures were kept lower in DEX group than Prop group until 8 hours after ICU admission. Other hemodynamic measurements, heart rate, pulmonary artery pressure and cardiac index showed no statistical difference. SAS and Ramsay score were better in DEX group early after ICU admission, and remained better until 10 hours later. CONCLUSION: Dexmedetomidine hydrochloride has no major hemodynamic nor other side effects after cardiovascular surgery. Dexmedetomidine hydrochloride could be used as an effective agent for postoperative sedation and analgesia in cardiovascular settings.

Aged↗
PubMed2005

Construction of perineuronal net-like structure by cortical neurons in culture.

Perineuronal nets consisting of chondroitin sulfate proteoglycans and hyaluronic acid are associated with distinct neuronal populations in mammalian brain. Whether neurons or glia cells produce these surface-associated chondroitin sulfate proteoglycan perineuronal nets has remained in question. In the present study, we observed perineuronal net-like structure by rat cortical neurons in dissociated culture using Wisteria floribunda aggulutinin, hyaluronic acid binding protein, and the antibodies recognizing chondroitin sulfate proteoglycans. The double labeling experiments showed that perineuronal net-like structure labeled with Wisteria floribunda aggulutinin was observed often at parvalbumin-positive neurons in dissociated cortical culture without glia. Perineuronal net-like structure was not seen at the early stage of culture, but they became visible concomitantly with neuronal maturation after longer culture. High magnification observation further demonstrated that Wisteria floribunda aggulutinin labeling on cortical neurons was seen as numerous puncta along surface of somata and proximal dendrites, but not axons and synapses. Perineuronal net-like structure on cultured neurons was also visualized using chondroitin sulfate proteoglycan-specific antibodies and hyaluronic acid binding protein. Double labeling study demonstrated that perineuronal net-like structure in cultured cortical neurons was composed of chondroitin sulfate proteoglycans such as neurocan and phosphacan. The hyaluronidase treatment of live neurons abolished cellular labeling of hyaluronic acid binding protein and concomitantly diminished that of Wisteria floribunda aggulutinin. These results indicate that cultured cortical neurons are able to construct perineuronal net-like structure without glial cells.

Animals↗
PubMed2005

Depressive mood is independently related to stroke and cardiovascular events in a community.

By means of a multivariate Cox model, we investigated the predictive value of a depressive mood on vascular disease risk in middle-aged community-dwelling people. In 224 people (88 men and 136 women; mean age: 56.8 +/- 11.2 years) of U town, Hokkaido (latitude: 43.45 degrees N, longitude: 141.85 degrees E), a chronoecological health watch was started in April 2001. Consultations were repeated every 3 months. Results at the November 30, 2004 follow-up are presented herein. 7-day/24-h blood pressure (BP) and heart rate (HR) monitoring started on a Thursday, with readings taken at 30-min intervals between 07:00 h and 22:00 h and at 60-min intervals between 22:00 h and 07:00 h. Data stored in the memory of the monitor (TM-2430-15, A and D company, Japan) were retrieved and analyzed on a personal computer with a commercial software for this device. Subjects were asked to answer a self-administered questionnaire inquiring about 15 items of a depression scale, at the start of study and again after 1-2 years. Subjects with a score higher by at least two points at the second versus first screening were classified as having a depressive mood. The other subjects served as the control group. The mean follow-up time was 1064 days, during which four subjects suffered an adverse vascular outcome (myocardial infarction: one man and one woman; stroke: two men). Among the variables used in the Cox proportional hazard models, a depressive mood, assessed by the Geriatric Depression Scale (GDS), as well as the MESOR of diastolic (D) BP (DBP-MESOR) and the circadian amplitude of systolic (S) BP (SBP-Amplitude) showed a statistically significant association with the occurrence of adverse vascular outcomes. The GDS score during the second but not during the first session was statistically significantly associated with the adverse vascular outcome. In univariate analyses, the relative risk (RR) of developing outcomes was predicted by a three-point increase in the GDS scale (RR = 3.088, 95% CI: 1.375-6.935, P = 0.0063). Increases of 5 mmHg in DBP-MESOR and of 3 mmHg in SBP-Amplitude were associated with RRs of 2.143 (95% CI: 1.232-3.727, P = 0.0070) and 0.700 (95% CI: 0.495-0.989, P = 0.0430), respectively. In multivariate analyses, when both the second GDS score and the DBP-MESOR were used as continuous variables in the same model, GDS remained statistically significantly associated with the occurrence of cardiovascular death. After adjustment for DBP-MESOR, a three-point increase in GDS score was associated with a RR of 2.172 (95% CI: 1.123-4.200). Monday endpoints of the 7-day profile showed a statistically significant association with adverse vascular outcomes. A 5 mmHg increase in DBP on Monday was associated with a RR of 1.576 (95% CI: 1.011-2.457, P = 0.0446). The main result of the present study is that in middle-aged community-dwelling people, a depressive mood predicted the occurrence of vascular diseases beyond the prediction provided by age, gender, ABP, lifestyle and environmental conditions, as assessed by means of a multivariate Cox model. A depressive mood, especially enhanced for 1-2 years, was associated with adverse vascular outcomes. Results herein suggest the clinical importance of repetitive assessments of a depressive mood and the need to take sufficient care of depressed subjects. Another result herein is that circadian and circaseptan characteristics of BP variability measured 7-day/24-h predicted the occurrence of vascular disease beyond the prediction provided by age, gender, depressive mood and lifestyle, as assessed by means of a multivariate Cox model. Earlier, we showed that the morning surge in BP on Mondays was statistically significantly higher compared with other weekdays. Although a direct association between the Monday surge in BP and cardiovascular events could not be demonstrated herein, it is possible that the BP surge on Monday mornings may also trigger cardiovascular events. We have shown that depressive people exhibit a more prominent circaseptan variation in SBP, DBP and the double product (DP) compared to non-depressed subjects. In view of the strong relation between depression and adverse cardiac events, studies should be done to ascertain that depression is properly diagnosed and treated. Chronodiagnosis and chronotherapy can reduce an elevated blood pressure and improve the altered variability in BP and HR, thus reducing the incidence of adverse cardiac events. This recommendation stands at the basis of chronomics, focusing on prehabilitation in preference to rehabilitation, as a public service offered in several Japanese towns.

Adult↗
PubMed2005

Arterial stiffness independently predicts cardiovascular events in an elderly community -- Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study.

We investigated the predictive value of arterial stiffness to assess cardiovascular risk in elderly community-dwelling people by means of a multivariate Cox model. In 298 people older than 75 years (120 men and 178 women, average age: 79.6 years), brachial-ankle pulse wave velocity (baPWV) was measured between the right arm and ankle in a supine position. The LILAC study started on July 25, 2000, consultation was repeated yearly, and the last follow-up ended on November 30, 2004. During this follow-up span of 1227 days, there were nine cardiovascular deaths, the cause of death being myocardial infarction for two men and three women or stroke for two men and two women. In Cox proportional hazard models, baPWV as well as age, Mini-Mental State Examination (MMSE), Hasegawa Dementia Scale Revised (HDSR) and the low-frequency/high-frequency (LF/HF) ratio showed a statistically significant association with the occurrence of cardiovascular death. A two-point increase in MMSE and HDSR score significantly protected against cardiovascular death, the relative risk (RR) being 0.776 (P = 0.0369) and 0.753 (P = 0.0029), respectively. The LF/HF ratio also was significant (P = 0.025), but the other indices of HRV were not. After adjustment for age and HDSR, a 200 cm/s increase in baPWV was associated with a 30.2% increase in risk (RR = 1.302, 95% CI: 1.110-1.525), and a 500 cm/s increase in baPWV with a 93.3% increase in risk (RR = 1.933, 95% CI: 1.300-2.874, P = 0.0011), whereas the LF/HF ratio was no longer associated with a statistically significant increase in cardiovascular mortality. In elderly community-dwelling people, arterial stiffness measured by means of baPWV predicted the occurrence of cardiovascular death beyond the prediction provided by age, gender, blood pressure and cognitive functions. baPWV should be added to the cardiovascular assessment in various clinical settings, including field medical surveys and preventive screening. The early detection of risk by chronomics allows the timely institution of prophylactic measures, thereby shifting the focus from rehabilitation to prehabilitation medicine, as a public service to several Japanese towns.

Aged↗
PubMed2005

Fractal analysis of heart rate variability and mortality in elderly community-dwelling people -- Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study.

AIM: Fractal analysis of heart rate (HR) variability (HRV) has been used as a new approach to evaluate the risk of mortality in various patient groups. Aim of this study is to examine the prognostic power of detrended fluctuation analysis (DFA) and traditional time- and frequency-domain analyses of HR dynamics as predictors of mortality among elderly people in a community. METHODS: We examined 298 people older than 75 years (average age: 79.6 years) and 1-h ambulatory ECG was monitored. During the last 10 min, deep respiration (6-s expiration and 4-s inspiration) was repeated six times in a supine position. Time-domain and frequency-domain measures were determined by the maximum entropy method. Scaling exponents of short-term (<11 beats, alpha 1) and longer-term (>11 beats, alpha 2) were determined by the DFA method. Six estimates, obtained from 10-min segments, were averaged to derive mean values for the entire recording span. These average values were denoted Alpha 1 and Alpha 2, estimates obtained during the first 10-min segment Alpha 1 S and Alpha 2 S, and those during the last 10-min segment Alpha 1E and Alpha 2E, respectively. The LILAC study started on July 25, 2000 and ended on November 30, 2004. We used Cox regression analysis to calculate relative risk (RR) and 95% confidence interval (CI) for all-cause mortality. Significance was considered at a value of P < 0.05. RESULTS: Gender, age and Alpha 2E showed a statistically significant association with all-cause mortality. In univariate analyses, gender was significantly associated with all-cause mortality, being associated with a RR of 3.59 (P = 0.00136). Age also significantly predicted all-cause mortality and a 5-year increase in age was associated with a RR of 1.49 (P = 0.01809). The RR of developing all-cause mortality predicted by a 0.2-unit increase in Alpha 2E was 0.58 (P = 0.00390). Other indices of fractal analysis of HRV did not have predictive value. In multivariate analyses, when both Alpha 2E and gender were used as continuous variables in the same model, Alpha 2E remained significantly associated with the occurrence of all-cause mortality (P = 0.02999). After adjustment for both gender and age, a 0.2-unit increase in Alpha 2E was associated with a RR of 0.61 (95% CI: 0.42-0.90, p = 0.01151). CONCLUSION: An intermediate-term fractal-like scaling exponent of RR intervals was a better predictor of death than the traditional measures of HR variability in elderly community-dwelling people. It is noteworthy that the longer-term (alpha 2) rather than the short-term fractal component (alpha 1) showed predictive value for all-cause mortality, which suggests that an increase in the randomness of intermediate-term HR behavior may be a specific marker of neurohumoral and sympathetic activation and therefore may also be associated with an increased risk of mortality.

Aged↗
PubMed2005

Common carotid intima-media thickness is predictive of all-cause and cardiovascular mortality in elderly community-dwelling people: Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study.

Several cohort studies have examined the association of carotid intima-media thickness (IMT) with the risk of stroke or myocardial infarction in apparently healthy persons. We investigated the predictive value of IMT of cardiovascular mortality in elderly community-dwelling people, beyond the prediction provided by age and MMSE, assessed by means of a multivariate Cox model. Carotid IMT and plaque were evaluated bilaterally with ultrasonography in 298 people older than 75 years (120 men and 178 women, average age: 79.6 years). The LILAC study started on July 25, 2000. Consultations were repeated every year. The follow-up ended on November 30, 2004. During the mean follow-up span of 1152 days, 30 subjects (21 men and nine women) died. Nine deaths were attributable to cardiovascular causes (myocardial infarction: two men and three women; stroke: two men and two women). The age- and MMSE-adjusted relative risk (RR) and 95% confidence interval (95% CI) of developing all-cause mortality was assessed. A 0.3 mm increase in left IMT was associated with a RR of predicted 1.647 (1.075-2.524), and a similar increase in right IMT with a RR of 3.327 (1.429-7.746). For cardiovascular mortality, the corresponding RR values were 2.351 (1.029-5.372) and 2.890 (1.059-7.891), respectively. Carotid IMT assessed by ultrasonography is positively associated with an increased risk of all-cause and cardiovascular death in elderly community-dwelling people.

Age Factors↗
PubMed2005

[Sutureless technique for oozing type postinfarction left ventricular free wall rupture].

We report our experience using a sutureless technique for oozing type postinfarction left ventricular free wall rupture. Several materials such as fibrin seat, autologous or heterologous pericardial patch, fibrin glue, and geratin-resorcin-formaldehyde (GRF) glue have been used. Nine patients, who developed postinfarction left ventricular free wall rupture, underwent surgical repair using a sutureless technique between 1999 and 2004. All patients survived and discharged our hospital without any postoperative complications. And all are alive an exellent condition in 5 to 44 months. A sutureless technique for the treatment of oozing type postinfarction left ventricular free wall rupture is simple, effective, and associated with a favorable outcome.

Aged↗
PubMed2005

[Jatene procedure with arch repair; usefulness of rapid two-stage repair].

Four cases of Jatene procedure with arch repair were performed since 2000 in our department. Two-stage repair was used in all cases and the extended end-to-end anastomosis and pulmonary artery banding (PAB) were performed in 3 cases as the initial repair. In a recent case of TGA type I with coarctation of the aorta (CoA), only subclavian flap aortoplasty was performed when he was 6-day-old and patent ductus arteriosus (PDA) was preserved and rapid two-stage Jatene procedure was performed when he was 8-day-old. There was no hospital or late death, or reoperation. The results of the two-stage Jatene procedure with arch repair was good and safe. Rapid two-stage repair was thought to be a useful choice especially for TGA type I with arch anomaly.

Aorta, Thoracic↗
PubMed2004

Skeletal phenotype of growing transgenic mice that express a function-perturbing form of beta1 integrin in osteoblasts.

Skeletal modeling entails the deposition of large amounts of extracellular matrix (ECM) to form structures tailored to withstand increasing mechanical loads during rapid growth. Specific ECM molecules bind to integrin receptors on the cell surface, thereby triggering a cascade of signaling events that affect critical cell functions. To evaluate the role of integrins during skeletal growth, transgenic mice were engineered to express a function-perturbing fragment of beta1 integrin consisting of the transmembrane domain and cytoplasmic tail under the control of the osteocalcin promoter (TG mice). Thus, transgene expression was targeted to mature cells of the osteoblast lineage, and herein we show that cultured cells resembling osteocytes from 90-day-old TG mice display impaired adhesion to collagen I, a ligand for beta1 integrin. To determine the influence of beta1 integrin on bones that are responsible for providing structural support during periods of rapid growth, we examined the phenotype of the appendicular skeleton in TG mice compared to wild type (WT) mice. According to radiographs, bones from mice of both genotypes between 14 and 90 days of age appeared similar in gross structure and density, although proximal tibiae from 35-90 days old TG mice were less curved than those of WT mice (72-92% TG/WT). Although there were only mild and transient differences in absolute bone mass and strength, once normalized to body mass, the tibial dry mass (79.1% TG/WT females), ash mass (78.5% TG/WT females), and femoral strength in torsion (71.6% TG/WT females) were reduced in TG mice compared to WT mice at 90 days of age. Similar effects of genotype on bone mass and curvature were observed in 1-year-old retired breeders, indicating that these phenotypic differences between TG and WT mice were stable well into adulthood. Effects of genotype on histomorphometric indices of cancellous bone turnover were minimal and evident only transiently during growth, but when present they demonstrated differences in osteoblast rather than osteoclast parameters. Together, these results suggest that integrin signals generated during growth enhance the acquisition of a skeletal mass, structure, and strength to withstand the mechanical loads generated by weight-bearing.

Animals↗
PubMed2004

Effects of disrupted beta1-integrin function on the skeletal response to short-term hindlimb unloading in mice.

The study was designed to determine whether beta1-integrin plays a role in mediating the acute skeletal response to mechanical unloading. Transgenic (TG) mice were generated to express a dominant negative form of beta1-integrin under the control of the osteocalcin promoter, which targets expression of the transgene to mature osteoblasts. At 63 days of age, wild-type (WT) and TG mice were subjected to hindlimb unloading by tail suspension for 1 wk. Pair-fed, normally loaded WT and TG mice served as age-matched controls. Bone samples from each mouse were processed for quantitative bone histomorphometry and biomechanical testing. The skeletal phenotype of TG mice was characterized by lower cancellous bone mass in the distal femoral metaphysis (-52%) and lumbar vertebral body (-20%), reduced curvature of the proximal tibia (-20%), and decreased bone strength (-20%) and stiffness (-23%) of the femoral diaphysis with relatively normal indexes of cancellous bone turnover. Hindlimb unloading for only 1 wk induced a 10% decline in tibial curvature and a 30% loss of cancellous bone in the distal femur due to a combination of increased bone resorption and decreased bone formation in both WT and TG mice. However, the strength and stiffness of the femoral diaphysis were unaffected by short-term hindlimb unloading in both genotypes. The observed increase in osteoclast surface was greater in unloaded TG mice (92%) than in unloaded WT mice (52%). Cancellous bone formation rate was decreased in unloaded WT (-29%) and TG (-15%) mice, but, in contrast to osteoclast surface, the genotype by loading interaction was not statistically significant. The results indicate that altered integrin function in mature osteoblasts may enhance the osteoclastic response to mechanical unloading but that it does not have a major effect on the development of cancellous osteopenia in mice during the early stages of hindlimb unloading.

Animals↗