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1.
The purpose of the present study was to determine whether vitamin K2 and growth hormone (GH) had an additive effect on the long bones in hypophysectomized young rats. Forty-eight female Sprague–Dawley
rats (6 weeks old) were assigned to the following five groups by the stratified weight randomization method: intact controls,
hypophysectomy (HX) alone, HX + vitamin K2 (30 mg/kg, p.o., daily), HX + GH (0.625 mg/kg, s.c., 5 days a week), and HX + vitamin K2 + GH. The duration of the experiment was 4 weeks. HX resulted in a reduction of the cancellous bone volume/total tissue volume
(BV/TV) at the proximal tibial metaphysis, as well as decreasing the total tissue area and cortical area of the tibial diaphysis.
These changes resulted from a decrease of the longitudinal growth rate and the bone formation rate (BFR)/TV of cancellous
bone, as well as a decrease of the periosteal BFR/bone surface (BS) and an increase of endocortical bone turnover (indicated
by the BFR/BS) in cortical bone. Administration of vitamin K2 to HX rats did not affect the cancellous BV/TV or the cortical area. On the other hand, GH completely prevented the decrease
of total tissue area and cortical area in cortical bone, as well as the decrease of marrow area and endocortical circumference,
by increasing the periosteal BFR/BS compared with that in intact controls and reversing the increase of endocortical bone
turnover (BFR/BS). However, GH only partly improved the reduction of the cancellous BV/TV, despite an increase of the longitudinal
growth rate and BFR/TV compared with those of intact controls. When administered with GH, vitamin K2 counteracted the reduction of endocortical bone turnover (BFR/BS) and circumference caused by GH treatment, resulting in
no significant difference of marrow area from that in untreated HX rats. These results suggest that, despite the lack of an
obvious effect on bone parameters, vitamin K2 normalizes the size of the marrow cavity during development of the bone marrow in young HX rats treated with GH. 相似文献
2.
Hirao M Hashimoto J Ando W Ono T Yoshikawa H 《Journal of bone and mineral metabolism》2008,26(3):260-264
Alendronate decreases the risk of femoral neck fracture by suppressing bone turnover, and also decreases the serum total osteocalcin
level. A low serum carboxylated osteocalcin level or high undercarboxylated osteocalcin level could be risk factors for femoral
neck fracture. Vitamin K mediates the carboxylation of osteocalcin, but the effect of alendronate therapy with or without
vitamin K2 supplementation remains unknown. Forty-eight postmenopausal women were enrolled in a 1-year prospective randomized trial
and assigned to alendronate monotherapy (5 mg/day) (group A, n = 26) or vitamin K2 (45 mg/day) plus alendronate (5 mg/day) (group AK, n = 22). Bone mineral density was measured by dual-energy X-ray absorptiometry at 0 and 12 months; bone turnover parameters
were measured at 0, 3, and 12 months. Four patients discontinued alendronate therapy, and we analyzed the remaining 44 patients
(23 in group A and 21 in group AK) who completed 1 year of treatment. Alendronate decreased undercarboxylated osteocalcin;
carboxylated osteocalcin was not affected. Addition of vitamin K2 enhanced the decrease of undercarboxylated osteocalcin levels and led to a greater increase of femoral neck bone mineral
density. Alendronate monotherapy does not decrease carboxylation of osteocalcin, and combination of vitamin K2 and alendronate brings further benefits on both osteocalcin carboxylation and BMD of femoral neck in postmenopausal women
with osteoporosis. 相似文献
3.
4.
Otomo H Sakai A Ikeda S Tanaka S Ito M Phipps RJ Nakamura T 《Journal of bone and mineral metabolism》2004,22(5):404-414
The relationship between bone turnover and bone tissue and material properties was examined in ovariectomized (OVX) rats treated with risedronate in combination with or without vitamin K2. Seventy female rats, 18 weeks of age, were assigned to 7 groups (n = 10): sham-operated + vehicle control; OVX + vehicle control; OVX + risedronate 0.1, 0.5, or 2.5mg/kg/day po; OVX + vitamin K2 30mg/kg/day po; OVX + vitamin K2 (30mg/kg/day) and risedronate (0.5mg/kg/day). Treatments were given daily for 9 months. To assess bone turnover, we measured serum osteocalcin and urinary deoxypyridinoline at 0, 3, and 9 months. To assess vertebral and femoral tissue and material properties, bone mass, bone mineral density (BMD by DXA), trabecular bone structure (vertebra: 3D-CT), cortical bone structure (femur: histomorphometry), biomechanical properties, and mineral properties (mineral-to-matrix and carbonate-to-phosphate ratios by Fourier transform infrared microspectroscopy) were measured ex vivo at 9 months. Ovariectomy increased bone turnover and induced significant loss of bone mass/density, structure, mineral properties (mineral-to-matrix ratio), and strength. Risedronate produced dose-dependent inhibition of the ovariectomy-induced increase in turnover and loss of bone mass/density, structure, mineral-to-matrix ratio, and strength, with a lowest effective dose of 0.1–0.5mg/kg/day. High-dose risedronate (2.5mg/kg/day) did not induce increases in any parameter above that of sham control. Vitamin K2 had no effects. In the OVX groups, urinary deoxypyridinoline at 3 and 9 months correlated significantly with vertebral BMD, trabecular bone volume, ultimate load, stiffness, and mineral-to-matrix ratio, and with femoral BMD, cortical area, and ultimate load. These results support the concept that changes in bone tissue and material properties can result directly from changes in bone turnover. Different effects among different drugs on material properties, including mineral-to-matrix ratio, may reflect differences in the relative rate and magnitude of osteoclastic bone resorption and osteoblastic primary bone mineralization. 相似文献
5.
Iwasaki Y Yamato H Murayama H Sato M Takahashi T Ezawa I Kurokawa K Fukagawa M 《Journal of bone and mineral metabolism》2003,21(3):154-160
Bisphosphonate is a potent inhibitor of bone resorption, which results in the increase of bone volume. However, bisphosphonate
treatment may lead to extremely low bone turnover and abnormal bone microstructure. In this study, we examined whether the
combination of bisphosphonate with vitamin K2 treatment may have beneficial effects on bone turnover and trabecular microstructure as well as on bone volume loss by using
tail-suspension model rats. In these model rats, bone mineral density (BMD) decreased with histological evidence of enhanced
bone resorption and suppressed bone formation. By bisphosphonate treatment, BMD was increased compared with that of tail-suspended
rats. Osteoclast surface per bone surface (Oc.S/BS) and number of osteoclasts per bone perimeter (N.Oc/B.Pm) were reduced
and mineral apposition rate (MAR) decreased, suggesting extreme suppression of bone turnover. However, trabecular structure
examined by microfocus CT was apparently abnormal. By contrast, combination of bisphosphonate with vitamin K2 leads to further increase of bone volume. MAR and BFR as well as Oc.S/BS and N.Oc/B.Pm were increased compared with those
of the bisphosphonate-treated group. However, abnormal structure of trabeculae in secondary spongiosa was not completely ameliorated.
These data suggested that concomitant use of vitamin K2 with bisphosphonate excessively ameliorates too much suppression of bone turnover while more efficiently preventing bone
volume loss.
Received: January 30, 2002 / Accepted: November 6, 2002
RID="*"
ID="*" Present address: Department of Health Sciences, Oita University of Nursing and Health Sciences, Oita, Japan
Acknowledgments. This work was supported in part by a Special Grant for Medical Research from Ministry of Post and Telecommunications, Japan
(to M.F.), a grant in aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology
(#13671115 to M.F.), and by a grant from the Research Society for Metabolic Bone Disease (to M.F.). We are grateful to Miss
Sachiko Suzuki for technical assistance.
Offprint requests to: M. Fukagawa 相似文献
6.
The present investigation evaluated the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on alveolar bone formation during tooth movement in rats. Orthodontic elastics were inserted between the maxillary first and second molars on bilateral sides in male rats. 1,25(OH)2D3 was injected locally, at the concentration of 10–10M, once every 3 days in the submucosal palatal area of the root bifurcation of the molar on the right side. Histomorphometric analysis revealed that tooth movement without application of 1,25(OH)2D3 decreased the mineral appositional rate (MAR) on the compression area at 7 days. Repeated injections of 1,25(OH)2D3 in the orthodontically treated animals distinctly stimulated alveolar bone formation on the mesial side at 14 days. There was a significant increase in MAR associated with elevated osteoblast surface (Ob.S/BS) value on the tension surface. These findings suggest that local application of 1,25(OH)2D3 enhances the reestablishment of supporting tissue, especially alveolar bone of teeth, after orthodontic treatment. 相似文献
7.
Satoshi Kato Kozo Sato Takeshi Sato Motoyoshi Gen Naohisa Miyakoshi 《Journal of bone and mineral metabolism》1997,15(4):193-205
Vitamin K2 is considered to have two different effects: one is to enhance bone formation, and the other is to suppress bone resorption.
However, as these effects have not been observed in a single experiment, it is unclear whether bone formation can proceed
during a state of accelerating bone resorption. We therefore examined the effects of vitamin K2 and calcitonin on a vitamin A-induced bone resorption model of thyroparathyroidectomized rats using bone histomorphometry
and bone metabolism markers. The seven groups of male Sprague-Dawley rats (6 weeks old) were sham operation of thyroparathyroidectomy
(TPTX) (sham group), TPTX (TPTX group), treated with vitamin A (20 mg/kg per day) from 11th to 20th day after TPTX (A group),
treated with vitamin A and vitamin K2 (30 mg/kg per day) or its vehicle from 11th to 20th day after TPTX [K group or K (veh) group], and treated with vitamin A
and calcitonin (10IU/kg/ per day) or its vehicle during the same period [CT group or CT (veh) group]. Serum and urine samples
were taken for marker determination on days 10, 13, 16, and 19 of TPTX and at death on the 21st day after TPTX. Undecalcified
sections (Villanueva bone stain) were made of the left tibiae and decalcified sections [tartrate-resistant acid phosphatase
(TRAP) stain] of the right tibiae. In the undecalcified sections, secondary trabeculae were used for histomorphometry, and
in the decalcified sections primary and secondary trabeculae were used. Serum Ca of the vitamin A-administered group was significantly
higher than that of the TPTX group, but this change was inhibited by vitamin K2 or calcitonin. Serum alkaline phosphatase (ALP) in the K group was significantly higher than in all the thyroparathyroidectomized
groups except the K (veh) group. In the undecalcified sections, although there was no significant difference between any of
the groups in bone volume, the K group showed an increase of osteoid surface and mineralizing surface. In the decalcified
sections, the K group showed a decrease of TRAP-positive areas compared to the K (veh) group in primary trabeculae. There
was no significant difference between the K and K (veh) groups in secondary trabeculae. Results from the CT group were compatible
with bone resorption inhibition in both bone metabolism markers and bone histomorphometry. We found that vitamin K2 enhances bone formation and suppresses bone resorption in areas with a high turnover of bone metabolism. Vitamin K2 is therefore expected to increase bone content if it is administered over an extended period. 相似文献
8.
This study aimed to evaluate the effects of different inflating gases used for ProSeal LMA (PLMA) cuff inflation on cuff pressure,
oropharyngeal structure, and the incidence of sore throat. Eighty patients (American Society of Anesthesiologists; ASA I–II)
were randomly divided into two groups. PLMA cuff inflation was achieved with appropriate volumes of 50% N2O + 50% O2 in group I and room air in group II, respectively. When the PLMA was removed, oropharyngeal examination was carried out immediately,
using a rigid optical telescope. Patients were asked about sore throat symptoms postoperatively. Cuff pressures were significantly
lower in group I, except at the initial pressure measurement. Cuff pressure was positively correlated with the length of the
operation in group II, and negatively correlated in group I. PLMA cuff inflation with room air led to increased cuff pressure
during the operation, possibly due to the diffusion of N2O into the cuff. We consider that a PLMA cuff inflated with an N2O-O2 mixture is convenient, especially in operations in which N2O has been used. 相似文献
9.
Background Local peritoneal effects of laparoscopic gases might be important in peritoneal biology during and after laparoscopic surgery.
The most commonly used gas, CO2, is known to be well tolerated, but also causes changes in acid-base balance. Helium is an alternative gas for laparoscopy.
Although safe, it is not widely used. In this study a method for monitoring peritoneal pH during laparoscopy was evaluated
and peritoneal pH during CO2 and helium pneumoperitoneum was studied as well as its systemic reflection in arterial pH.
Methods For these experiments 20 pigs were used, with ten exposed to pneumoperitoneum with CO2, and ten to helium. Peritoneal and sub-peritoneal pH were continuously measured before and during gas insufflation, during
a 30-minute period with a pneumoperitoneum and during a 30-minute recovery period. Arterial blood-gases were collected immediately
before gas insufflation, at its completion, at 30 minutes of pneumoperitoneum and after the recovery period.
Results Peritoneal pH before gas insufflation was in all animals 7.4. An immediate local drop in pH (6.6) occurred in the peritoneum
with CO2 insufflation. During pneumoperitoneum pH declined further, stabilising at 6.4, but was restored after the recovery period
(7.3). With helium, tissue pH increased slightly (7.5) during insufflation, followed by a continuous decrease during pneumoperitoneum
and recovery, reaching 7.2. Systemic pH decreased significantly with CO2 insufflation, and increased slightly during helium insufflation. Systemic pH showed co-variation with intra-peritoneal pH
at the the end of insufflation and after 30 minutes of pneumoperitoneum.
Conclusions Insufflation of CO2 into the peritoneal cavity seemed to result in an immediate decrease in peritoneal pH, a response that might influence biological
events. This peritoneal effect also seems to influence systemic acid-base balance, probably due to trans-peritoneal absorption. 相似文献
10.
Cannabinoids Stimulate Fibroblastic Colony Formation by Bone Marrow Cells Indirectly via CB<Subscript>2</Subscript> Receptors 总被引:1,自引:0,他引:1
Recently, the cannabinoid receptors CB1 and CB2 were shown to modulate bone formation and resorption in vivo, although little is known of the mechanisms underlying this. The effects of cannabinoids on mesenchymal stem cell (MSC) recruitment
in whole bone marrow were investigated using either the fibroblastic colony-forming unit (CFU-f) assay or high-density cultures
of whole bone marrow. Levels of the CB1 and CB2 receptors were assessed by flow cytometry. Treatment of CFU-f cultures with the endocannabinoid 2-arachidonylglycerol (2-AG)
dose-dependently increased fibroblastic and differentiated colony formation along with colony size. The nonspecific agonists
CP 55,940 and WIN 55,212 both increased colony numbers, as did the CB2 agonists BML190 and JWH015. The CB1-specific agonist ACEA had no effect, whereas the CB2 antagonist AM630 blocked the effect of the natural cannabinoid tetrahydrocannabivarin, confirming mediation via the CB2 receptor. Treatment of primary bone marrow cultures with 2-AG stimulated proliferation and collagen accumulation, whereas
treatment of subcultures of MSC had no effect, suggesting that the target cell is not the MSC but an accessory cell present
in bone marrow. Subcultures of MSCs were negative for CB1 and CB2 receptors as shown by flow cytometry, whereas whole bone marrow contained a small population of cells positive for both receptors.
These data suggest that cannabinoids may stimulate the recruitment of MSCs from the bone marrow indirectly via an accessory
cell and mediated via the CB2 receptor. This recruitment may be one mechanism responsible for the increased bone formation seen after cannabinoid treatment
in vivo. 相似文献
11.
Yüksel Arikan Murat Tosun Volkan Şaykol Serpil Kalkan Serpil Erdem 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2008,393(6):877-882
Backgrounds and aims Laparoscopic surgery techniques have been increasingly preferred to classic laparotomy by surgeons since 1987. However, this
method has some important adverse effects on intra-abdominal organs. The aim of this study is to evaluate the effects of different
pressures of CO2 on apoptosis and p53 expression in cells in liver and spleen.
Methods In total, 30 male Sprague–Dawley rats were used in the study. CO2 was insufflated into the intra-abdominal cavity via angiocatheter cannule by an insufflator in two different pressures of
10 and 20 mm Hg for 60 min. However, in the control group, only cannule was inserted into the intra-abdominal cavity, but
no gas was insufflated. After 60 min, the rats were killed and laparotomy was applied. The liver and spleen were excised.
The samples were histologically processed and immunohistochemistry was applied.
Results All the data revealed that the number of apoptotic cells in liver and spleen increases in proportion to CO2 pressure level. No p53 expression was detected in both organs.
Conclusion CO2 pressure level and application time may affect on cells living in liver and spleen. High pressure and/or long application
time may cause releasing of cytokines and superoxide radicals from these organs’ cells, and transient or serious organ dysfunctions
may occur. 相似文献
12.
Summary Background. The exact effects of decompressive craniectomy on intracranial pressure (ICP) and cerebral tissue oxygenation (ptiO2) are still unclear. Therefore, we have monitored ICP and ptiO2 intra-operatively and correlated these values to different operative steps during craniectomy.Methods. ICP and ptiO2 values have been monitored both, simultaneously and continuously, in 15 patients with cerebral edema due to posttraumatic or postischemic brain swelling. Indications for craniectomy were an increase in ICP above 25 mmHg or a decrease in ptiO2 below 10 mmHg resistant to conservative treatment (e.g. mannitol, hyperventilation, adequate arterial blood oxygenation, etc.). In all cases, we performed a fronto-temporo-parietal craniectomy (15×12 cm) and dura enlargement with galea-periosteum. During craniectomy, monitoring of ICP and ptiO2 in the affected hemisphere was continued. Values were recorded and correlated with the different operative steps.Findings. We performed craniectomy according to our treatment protocol in 5 patients. Prior to surgery, mean ICP values were 25.6 mmHg (range: 23–29 mmHg), mean ptiO2 values were 5.9 mmHg (range: 2.4–9.5 mmHg), and mean CPP values were 66 mmHg (range: 60–70 mmHg). After removing the bone flap, ICP values dropped to physiological values (mean: 7.4 mmHg), whereas ptiO2 values increased only slightly (mean: 11 mmHg). Opening of the dura resulted in a further decrease of ICP (mean 4.8 mmHg) and an increase of ptiO2 to normal limits (mean: 18.8 mmHg). After skin closure, mean ICP was 6.8 mmHg and mean ptiO2 was 21.7 mmHg, respectively. We found a significant decrease of ICP after craniectomy (p<0.042) and after dura enlargement (p<0.039) as well as a statistically significant increase in ptiO2 after craniectomy (p<0.043) and after dura enlargement (p<0.041).Conclusion. As a large bone flap in decompressive craniectomy is essential for adequate ICP reduction, the results of the presented cases suggest that dura enlargement is the crucial step to restore adequate brain tissue oxygenation and that ptiO2 monitoring could be an important tool for timing craniectomy in the future. 相似文献
13.
Vitamin D2 and D3 are generally considered equipotent in humans. A few studies have reported that serum 25OHD levels are higher in vitamin D3- compared with vitamin D2-supplemented subjects. As both vitamin D2 and D3 supplements are commonly used by elderly in United States, in the present study we determined the effect of self-reported vitamin D2 and vitamin D3 supplement use on serum total 25OHD levels according to season in elderly women aged 65–77 years. Serum total 25OHD levels were determined in winter and summer in unsupplemented women (N = 307) and in women who reported taking vitamin D2 (N = 56) and vitamin D3 (N = 55) supplements by competitive protein binding assay. In vitamin D2-supplemented women, the contribution of vitamin D2 and D3 to the mean serum total 25OHD level was assessed by HPLC. In summer, there were no significant differences in the mean total serum 25OHD levels (ng/ml) among the vitamin D2 (32 ± 2.1), vitamin D3 (36.7 ± 1.95), and unsupplemented (32.2 ± 0.95) groups. In winter, the mean serum total 25OHD levels were higher in women on vitamin D2 (33.6 ± 2.34, P < 0.05) and vitamin D3 (29.7 ± 1.76, NS) supplements compared with unsupplemented women (27.3 ± 0.72). In vitamin D2-supplemented women, about 25% of the mean serum total 25OHD was 25OHD2, in both summer and winter. Twelve percent of unsupplemented women and 3.6% of vitamin D-supplemented women had a mean serum total 25OHD level below 15 ng/ml in winter. In elderly subjects, both vitamin D2 and Vitamin D3 supplements may contribute equally to circulating 25OHD levels, with the role of vitamin D supplement use being more predominant during winter.
This work was presented in part as an abstract at Second Joint Meeting of the American Society for Bone and Mineral Research and The International Bone and Mineral Society, San Francisco, CA, 1–6 December 1998. 相似文献
14.
The effect of different levels of peritoneal CO<Subscript>2</Subscript> pressure on bleeding time of spleen capsule injury 总被引:1,自引:0,他引:1
Aims: The authors, in contrast to similar injuries with open surgery, had observed spontaneous hemostasis of relatively large spleen capsule injuries during laparoscopic surgery. Methods: Standard spleen injuries were carried out in 5 anesthetized mongrel dogs at different CO2 pressures and in open surgery. Bleeding was checked every minute by wiping around the injury but not removing the clot. Bleeding time was measured until no more oozing was detected. At every pressure level 3-3 measurements were done and analyzed. Parenchymal pressure of the spleen and systemic blood pressure were detected with direct catheter implantation. Results: In open surgery the average bleeding time was 15.2 min; at 5, 15, and 25 mmHg CO2 pressures bleeding times were 12.3, 10.6, and 9.8 min, respectively. The parenchymal pressure of the spleen (5–6 mmHg) rose synchronously with peritoneal pressure, but no significant changes in systemic blood pressure were seen. Conclusion: Peritoneal CO2 pressure may counterweight the parenchymal pressure of the spleen, thus helping hemostasis. There seems to be an inverse proportion between peritoneal pressure and bleeding time. In case of spleen capsule injury during laparoscopic surgery, chances for spontaneous hemostasis are much better compared to open surgery. Attention must be paid to maintain adequate peritoneal pressure. 相似文献
15.
Miki T Nakatsuka K Naka H Kitatani K Saito S Masaki H Tomiyoshi Y Morii H Nishizawa Y 《Journal of bone and mineral metabolism》2003,21(3):161-165
Twenty elderly osteoporotic women with vertebral fracture(s) were randomly allocated to two groups; women in the MK4 group received calcium with menaquinone 4 (MK4) at a dose of 45 mg/day for 2 weeks, and women in the control group received calcium alone for the same period. Serum intact
osteocalcin (OC) and undercarboxylated osteocalcin (uc-OC) levels were measured by immunoradiometric assay and enzyme immunoassay,
respectively, at baseline and on the 7th and 14th days following the start of the treatment. There were no differences in
the baseline data including age, weight, phylloquinone, menaquinone 4, menaquinone 7, OC, and uc-OC levels between the MK4 group and the control group. Administration of MK4 significantly raised the MK4 level from 0.20 ± 0.10 (mean ± SE) pg/ml to 15.09 ± 5.62 pg/ml (P < 0.04), and reduced serum uc-OC levels from 2.80 ± 0.93 ng/ml to 1.76 ± 0.56 ng/ml (P < 0.05) at the end of the study, respectively. No significant changes in these levels were observed in the control group.
Serum OC levels were stable during the period in both groups. In this randomized prospective study, the MK4 group shows a reduction in the serum uc-OC level within 2 weeks without any significant change in OC, suggesting that the
uc-OC is changed to carboxylated OC. This early effect of MK4 on bone metabolism may be estimated by the measurement of serum uc-OC in elderly osteoporotic women with vertebral fractures.
Received: January 21, 2002 / Accepted: November 6, 2002
Offprint requests to: T. Miki 相似文献
16.
Pockaj BA Basu GD Pathangey LB Gray RJ Hernandez JL Gendler SJ Mukherjee P 《Annals of surgical oncology》2004,11(3):328-339
Background: In several neoplastic diseases, including breast cancer, immunosuppression correlates with disease stage, progression, and outcome. Thus, thorough analysis of immune parameters in breast cancer patients may be beneficial in designing effective anticancer immune-based therapies.Methods: We investigated dendritic cell and T-cell function in breast cancer patients at various stages of the disease and in age-matched controls. We also evaluated cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) levels within the tumor milieu and in the circulation.Results: T cells from cancer patients showed decreased proliferation in response to CD3 antibody stimulation. Analysis of T-cell helper type 1 and 2 cytokines revealed reduced levels of interferon-, tumor necrosis factor-, interleukin (IL)-12, and IL-2 and increased levels of IL-10 and IL-4. Dendritic cells from these patients showed significantly reduced expression of co-stimulatory molecules (B7 and CD40) and demonstrated reduced phagocytic ability, reduced antigen presentation to T cells, and reduced ability to mature in response to lipopolysaccharide. Data revealed increased synthesis of PGE2, an immune suppressor, along with increased expression of COX-2, a key regulator of PGE2 synthesis.Conclusions: COX-2–induced PGE2 may contribute to immunosuppression and may directly block antitumor immunity while promoting tumor growth, providing us with the rationale for using COX-2 inhibition combined with immunotherapy. 相似文献
17.
Tjellesen Lone Gotfredsen Anders Christiansen Claus 《Calcified tissue international》1985,37(3):218-222
Summary In 22 epileptic outpatients treated for at least 1 year with phenobarbitone/phenytoin the local and total bone mass, together
with serum and urinary indices of calcium metabolism, were measured before and during treatment with either vitamin D2 or D3, 4,000 IU daily for 24 weeks. The results showed a distinct difference in the action of the two vitamins on bone metabolism
during anticonvulsant treatment. The bone mass increased during treatment with vitamin D2, whereas the vitamin D3-treated patients showed unchanged values of bone mass, but an increased excretion rate of calcium, probably caused by increased
intestinal calcium absorption. The data demonstrate that vitamins D2 and D3 (or their metabolites) have quantitative different effects in patients treated with phenobarbitone/phenytoin. 相似文献
18.
Summary Vitamin K mediates the synthesis of proteins regulating bone metabolism. We have tested whether high vitamin K2 intake promotes bone mineral density and bone strength. Results showed that K2 improved BMC and femoral neck width, but not DXA-BMD. Hence high vitamin K2 intake may contribute to preventing postmenopausal bone loss.
Introduction Vitamin K is involved in the synthesis of several proteins in bone. The importance of K vitamins for optimal bone health has
been suggested by population-based studies, but intervention studies with DXA-BMD as a clinical endpoint have shown contradicting
results. Unlike BMC, DXA-BMD does not take into account the geometry (size, thickness) of bone, which has an independent contribution
to bone strength and fracture risk. Here we have tested whether BMC and femoral neck width are affected by high vitamin K
intake.
Methods A randomized clinical intervention study among 325 postmenopausal women receiving either placebo or 45 mg/day of vitamin K2 (MK-4, menatetrenone) during three years. BMC and hip geometry were assessed by DXA. Bone strength indices were calculated
from DXA-BMD, femoral neck width (FNW) and hip axis length (HAL).
Results K2 did not affect the DXA-BMD, but BMC and the FNW had increased relative to placebo. In the K2-treated group hip bone strength remained unchanged during the 3-year intervention period, whereas in the placebo group bone
strength decreased significantly.
Conclusions Vitamin K2 helps maintaining bone strength at the site of the femoral neck in postmenopausal women by improving BMC and FNW, whereas
it has little effect on DXA-BMD. 相似文献
19.
C. J. Andresen M. Moalli C. H. Turner E. Berryman R. Pero C. M. Bagi 《Calcified tissue international》2008,83(6):393-403
Intermittent combination of an anabolic agent to promote bone formation and an antiresorptive agent that would prevent further
bone loss is a theoretically attractive approach for restoring bone mass. We tested the potential of intermittently dosed
calcitriol and calcitonin (CT) to restore bone properties in ovariectomized (Ovx) rats. Rats had Ovx or sham surgery at 8 weeks
old and 4 weeks later were assigned to experimental groups: (1) sham vehicle, (2) Ovx vehicle, (3) Ovx + parathyroid hormone
(PTH, 40 μg/kg), and (4) Ovx + calcitriol (2 μg/kg) + CT (2 μg/kg). Group 3 received PTH every week throughout the study,
and group 4 received calcitriol at weeks 1, 3, 5, and 7 and CT at weeks 2, 4, 6, and 8. Dosing was carried out for 8 weeks
with serum, and micro-computed tomographic analysis was done at 0, 4, and 8 weeks. Femurs and tibias were used for radiological
analyses and for mechanical testing. Dosing with PTH improved bone mass and structure of cancellous bone at metaphyses of
tibias and femurs as well as properties of cortical bone including geometry and strength. Intermittent dosing with calcitriol
and CT was less potent in correcting loss of cancellous bone relative to treatment with PTH and had no effect on cortical
bone parameters. However, intermittent dosing with calcitriol and CT was robust enough to improve cancellous bone mass and
structure through bone formation without causing deleterious side effects. Our data provide additional evidence that therapies
can be devised to ameliorate the skeletal defects associated with established osteoporosis. 相似文献
20.
Wataru Sakamoto Haruo Isomura Katsutoshi Fujie Tadashi Iizuka Jun Nishihira Gen Tatebe Kazuhiko Takahashi Yusuke Osaki Michio Komai Hiroshi Tamai 《Osteoporosis international》2005,16(12):1604-1610
Reactive oxygen species (ROS) may contribute to aging and osteoporosis resulting from marked decreases in plasma antioxidants in aged osteoporotic women. On the other hand, high-dose vitamin K2 (menaquinone-4: menatrenone, MK-4) supplementation has been reported to reduce ovariectomy-induced bone loss in rats and to decrease osteoporotic fracture in postmenopausal women. However, the mechanism by which vitamin K2 prevents osteoporosis is unclear. Recently, vitamin K2 has been suggested to preserve antioxidant activity as a novel function. Therefore, we investigated the effect of vitamin K2 on the osteoporosis of aged rats by evaluating the relationships between serum antioxidant levels and bone metabolism. Aged female rats exhibited significantly lower serum alkaline phosphatase activity and osteocalcin level, together with lower serum levels of antioxidants such as 17-estradiol, macrophage migration inhibitory factor (MIF) and glutathione peroxidase (GPx) activity, as compared with young female rats. On the other hand, vitamin K2 supplementation (500 mg/kg, food intake) for 98 days led to a significantly increased serum vitamin K2 level (3,045±915 ng/ml in the vitamin K2 supplemented group vs. 4.6±3.4 ng/ml in the control diet group; P <0.0001) with increased serum alkaline phosphatase activity and MIF level ( P <0.05). Unexpectedly, however, it failed to increase the serum level of antioxidants such as GPx. Nor did it affect bone metabolism markers such as oteocalcin and osteopontin, which were significantly lower than in the young female rats ( P <0.05). Finally, the histomorphometric properties of the proximal tibia in the femur were not altered by vitamin K2. These results suggest that high-dose vitamin K2 supplementation neither improves lowered antioxidant levels nor stimulates bone formation in aged rats. 相似文献