Regulation of sodium-dependent phosphate transport in osteoclasts

Osteoclasts are the primary cells responsible for bone resorption. They are exposed to high ambient concentrations of inorganic phosphate (Pi) during the process of bone resorption and they possess specific Pi-transport system(s) capable of taking up Pi released by bone resorption. By immunochemical studies and PCR, we confirmed previous studies suggesting the presence of an Na-dependent Pi transporter related to the renal tubular "NaPi" proteins in the osteoclast. Using polyclonal antibodies to NaPi-2 (the rat variant), an approximately 95-kD protein was detected, localized in discrete vesicles in unpolarized osteoclasts cultured on glass coverslips. However, in polarized osteoclasts cultured on bone, immunofluorescence studies demonstrated the protein to be localized exclusively on the basolateral membrane, where it colocalizes with an Na-H exchanger but opposite to localization of the vacuolar H-ATPase. An inhibitor of phosphatidylinositol 3-kinase, wortmannin, and an inhibitor of actin cytoskeletal organization, cytochalasin D, blocked the bone-stimulated increase in Pi uptake. Phosphonoformic acid (PFA), an inhibitor of the renal NaPi-cotransporter, reduced NaPi uptake in the osteoclast. PFA also elicited a dose-dependent inhibition of bone resorption. PFA limited ATP production in osteoclasts attached to bone particles. Our results suggest that Pi transport in the osteoclast is a process critical to the resorption of bone through provision of necessary energy substrates.     

History of urethral catheters and their balloons: drainage, anchorage, dilation, and hemostasis

Male urethral catheterization, as practiced in early Greece, was made possible by a sound knowledge of anatomy. It has been preserved by written tradition and advanced by the development of new materials. Balloon dilation, conceived and practiced more than 160 years ago by urologists, has undergone a similar cycle. Some useful ideas, once conceived, have been forgotten and have surfaced again, decades, sometimes centuries, later as new inventions.     

The effect of combined estrogen/progestogen treatment in women with hyperprolactinemic amenorrhea

Eleven women with hyperprolactinemic amenorrhea were treated with a combined estrogen/progestogen preparation (Loestrin 30) for 3 months as hormone replacement therapy because of estrogen deficiency, with a view to protection against osteoporosis. Serum prolactin levels rose during the 1st month of treatment (p < 0.05) but did not rise significantly further during the 2nd and 3rd months. The levels rose in proportion to pretreatment levels by 28% (median), and fell significantly but not completely during the 1-week treatment-free intervals. After the study period, prolactin values appeared to remain stable in those women who continued longer on treatment, and returned to around pretreatment values in those who stopped. In one woman there was radiological evidence of pituitary tumor growth during treatment. This study shows that estrogen/progestogen treatment in standard contraceptive dosage usually leads to only moderate and non-progressive stimulation of pituitary activity in women with hyperprolactinemic amenorrhea, but occasional excessive growth of a prolactinoma can occur and treatment needs to be monitored. Women with relatively high prolactin levels seem to be at particular risk. Safer variations of estrogen therapy such as lower dosage or combination with a protective low dose of a dopamine agonist should also be considered.     

戴上它吧，给你自由！

自从黑猩猩习惯直立行走，学会制造并使用工具以来，双手在整个进化过程中起到了绝对重要的作用。可是，5万年后的今天，我们引以为豪的现代文明却将我们的双手重新束缚起来——现在几乎人手一部的手机，已经成为掌中把握时间最长的东西。无论何处，随处可见一只手拿着手机谈笑风生的路人；走在路上，汽车的驾驶员不得不冒着发生交通事故的危险，     

HPLC-ABTS~+·在线法筛选细叶杜香叶部抗氧化活性成分

利用HPLC-ABTS+.在线法对细叶杜香叶中的抗氧化活性成分进行筛选和分析鉴定,结果表明:在细叶杜香甲醇提取物的乙酸乙酯萃取组分中筛选到2种抗氧化活性成分,经质谱和核磁共振波谱分析鉴定为染料木苷和槲皮素。     

Surgical strategy in gastric cancer in aged patients

The trend of the National mortality rate for gastric cancer in the general population and in the old people between 1955 and 1990 was studied. A decreased incidence of mortality in the general population whereas an increased mortality rate in elderly was found. Between 1990 and 1994, 17 patients over 70 years of age were operated on for gastric cancer. The influence of the ASA classification on postoperative complications was then evaluated registering a significant statistical difference between patients included in ASA III group and or > and major complications and mortality (P = 0.044). The surgical strategy in the management of elderly patients with gastric cancer is also discussed.     

Enhancement of radiosensitivity of rat rhabdomyosarcoma R1H with normobaric carbogen and hyperbaric oxygen (HBO) using conventionally fractionated irradiation

Hypoxic clonogenic cells are an important contributory factor in tumour radioresistance. The objective of the present study was to evaluate whether hyperbaric oxygen enhances tumour radiosensitivity, using a conventionally fractionated irradiation schedule, and whether the radiosensitizing potential is different from carbogen. Experiments were performed using the rhabdomyosarcoma R1H model transplanted subcutaneously in the flank of WAG/Rij rats. A total of 30 X-ray fractions of 2 Gy were given either in air, normobaric carbogen or high pressure oxygen (HPO) (240 kPa, 2.37 atm) without anaesthesia. The time taken to achieve complete remission was 38.7 +/- 3.6 days, 36.7 +/- 2.7 days and 32.4 +/- 4.1 days for air, normobaric carbogen and HBO, respectively. The differences between air and HBO (p = 0.002) and carbogen and HBO (p = 0.015) were significant. Use of carbogen and HBO produced the same local control probability at 150 days and this was significantly higher than local control under ambient conditions (p < 0.0001). It was concluded that the time to achieve complete remission of the rat rhabdomyosarcoma R1H can be shortened by HBO. Furthermore, both HBO and carbogen give higher local control probabilities than treatment under ambient conditions when used with a conventionally fractionated radiation schedule.