Platelet-derived growth factor (PDGF)-AA: a self-imposed cytokine in the proliferation of human fetal osteoblasts

PDGF, a multiple mitogen, stimulates osteoblast replication and bone collagen degradation, and it has been described as a key factor in bone metabolism. Recently, PDGF was disclosed to be the autocrine cytokine of human osteoblasts. PDGF's effect on human bone development needs elucidation, and the mechanism of PDGF-AA autocrining remains unclear. In this work, osteoblasts were isolated from human fetal calvaria which resemble the cells in developing bone tissue. Using an in vitro model, the effect of PDGF-AA on the cells was investigated with the results showing that (i) after PDGF-AA was added into the medium for 24 h, PCI of the cells increased by 48.2% (P<0.05), and PCI decreased after the removal of PDGF-AA. (ii) 24 h after treatment with PDGF-AA, the percentage of osteoblasts in G(0)/G(1)phase decreased and that in S phase increased. (iii) The expression of PDGF-A mRNA was upregulated by PDGF-AA, PDGF-BB, TGFbeta,and bFGF respectively. These results proved that: (i) PDGF-AA enhances cell replication by accelerating cell recycle and inducing the quiescent cells into the proliferation portion of cell cycle. (ii) PDGF-AA is a self-imposed cytokine in human fetal osteoblast replication.

Modulation of transforming growth factor beta to platelet-derived growth factor receptor-alpha of human osteoblasts

OBJECTIVE

To investigate the mechanism and the significance of TGF beta in modulating the expression of Platelet-Derived Growth Factor Receptor-alpha (PDGFR-alpha) in human osteoblasts.

METHODS

The osteoblasts were isolated from human fetal calvaria. The percentage of cell increase (PCI) in every 4 hours was calculated to demonstrate the proliferation of osteoblasts affected by PDGF-AA and TGF beta. The osteoblasts were cultured with TGF beta for 24 hours and with PDGF-AA for another 24 hours, and the cells proliferation was shown by PCI too. The osteoblasts were cultured with TGF beta for 24 h, and the PDGFR-alpha of the cells were measured by immunofluorescent analysis.

RESULTS

PCI was increased by 48.2% and 22.4% after PDGF-AA and TGF beta were added into the medium for 24 hours respectively (P < 0.05), and PCI decreased after the removal of the two cytokines. Preincubated with TGF beta for 24 hours and then stimulated with PDGF-AA, PCI grew slowly. TGF beta downregulated the expression of the PDGFR-alpha.

CONCLUSION

TGF beta can downregulate the mitogenesis of PDGF-AA by lowering the number of PDGFR-alpha.

[Detection of 17-ketosteroid and 17-hydroxycorticosteroid in urine after separation and collection by foam rubber]

Using foam rubber 17-ketosteroid (17-KS) and 17-hydroxycorticosteroid (17-OHCS) were separated and collected in urine. 17-KS and 17-OHCS were eluted down from the foam rubber with alcohol, colour reaction can be respectively produced by m-dinitrobenzene and phenyhydrazine hydrocholoride, then both of them were detected by spectro-photometry. The standard deviation of this method was +/- 0.032, and its minimum detectable concentration was 0.01 microgram.ml-1. The recovery rate of 17-KS and 17-OHCS estimation was from 99.0% to 101.0%, with co-efficients of variation less than 6.23%.

[Collagen expression of intra-acinar pulmonary arteries and right ventricle and intervention of Radix Astragali in rats with hypoxic pulmonary hypertension]

OBJECTIVE

To investigate the collagen expression effect of intra-acinar pulmonary arteries and the right ventricle and to observe the intervention effect of Radix Astragali in rats with hypoxic pulmonary hypertension.

METHODS

Wistar male rats were divided into three groups: hypoxia group, which was fed in hypoxic environment (oxygen concentration was 9%-12%) under normal atmospheric pressure for three weeks (12 hours every day); intervention group, which was abdomenly injected with Radix Astragali and fed in the same environment as hypoxia group; and control group, which was fed in normal environment. Pulmonary artery pressure and cardiac output of the right ventricle were measured with catheterization and Fick's method. Protein expression of collagen in intra-acinar pulmonary arteries was assessed with histopathologic method. mRNA expressions of collagen in the right ventricle, and endothelin-1 and nitric oxide synthase in lung tissue were evaluated by RT-PCR technique.

RESULTS

Compared with those in control group, pulmonary artery pressure and protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were obviously increased in hypoxia group (mean pulmonary artery pressure: (24.8 +/- 3.6) mm Hg vs (18.8 +/- 1.7) mm Hg, P < 0.01; protein expression of collagen: (20.4 +/- 4.5) AU vs (3.4 +/- 1.1) AU (P < 0.01), but mRNA expression of nitric oxide synthase in lung tissue was declined. Compared with the data obtained in hypoxia group, cardiac output and mRNA expression of nitric oxide synthase in lung tissue were raised in intervention group (cardiac output: [(141 +/- 20) ml/min vs (118 +/- 40) ml/min, P < 0.01], but protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were markedly decreased (protein expression of collagen: [(5.6 +/- 1.2) AU vs (20.4 +/- 4.5) AU, P < 0.001].

CONCLUSION

Changes of collagen expression in intra-acinar pulmonary arteries and right ventricle are one of the most important features in remodeling of pulmonary arteries and right ventricle in hypoxic pulmonary hypertension. Radix Astragali can partly inhibit the remodeling of pulmonary arteries and right ventricle, and regulate mRNA expression of endothelin-1, nitric oxide synthase, and collagen, thus contributing to the treatment of hypoxic pulmonary hypertension.

Psychological conditions diagnosed among veterans seeking Department of Defense Care for Gulf War-related health concerns

The Comprehensive Clinical Evaluation Program is a US military program that provides a voluntary, clinically oriented evaluation for Gulf War health concerns. This article presents administrative data on psychological conditions (as coded using the International Classification of Diseases, 9th Revision) from the first year of the program. The most commonly diagnosed psychological conditions were medically unexplained physical-symptom syndromes; depression and anxiety, including post-traumatic stress disorder; and alcohol abuse or dependence. Psychological conditions were significantly related to a higher number of workdays lost, and the 19% of veterans with a primary diagnosis of a psychological condition reported 28% of the lost workdays among veteran who participated. Stressful Gulf War experiences were weakly but significantly related to psychological conditions. We conclude that among Gulf War veterans seeking evaluation for Gulf War-related health concerns, psychological conditions are common and are associated with important occupational morbidity.

[The study on edge detection method of medical color image]

Considering the specificity of the medical color image, in this paper a medical color image is decomposed as three color orthogonal feature: I1, I2 and I3 in K-L transformation method, and Kirsch algorithm is used to detect the edge of the monochrome image I1 including rich information. Finally, both clarity edge and rich detail of color backdisplay image are gained, if we adopt I2 and I3 to compensate I1.

[Detection of human cytomegalovirus infection in blood donor population by the polymerase chain reaction]

Samples of peripheral blood from 76 different donors were detected for the presence of human cytomegalovirus (HCMV) DNA by polymerase chain reaction (PCR). The results showed that HCMVs were present in 39 out of 76 blood donors which reached an infection positive rate of 51.3%. In addition, the sensitivity and specificity on PCR were tested, it also indicated that the sensitivity can reach the level of 5fg.microliter-1. The method is simple, rapid, highly sensitive and specificity. It can be considered as a diagnostic measure in clinical detection of HCMV.

[Preventional intervention of myocardial interstitial fibrosis in murine myocardium with acute myocarditis]

OBJECTIVES

To explore that whether intervening the fibrosis of heart interstitium in acute viral myocarditis is practical or not, and offer the experimental basis for clinic to choose the optimum period to intervene myocardial fibrosis.

METHODS

Animals were divided into three groups: myocarditis, myocarditis intervened by Losartan, and normal control. The death rate of every group was compared. HE staining and picrosirius red staining and circularly polarized light were used to investigate myocardial collagen expression. Cardiac output was measured by impedance differentiation, and cardiac index was computed to evaluate cardiac function.

RESULTS

The death rate of the group with Losartan was 75.0%, and that of the myocarditis group was 41.7%. The cardiac index of the group with the drug was 0.014 +/- 0.001 ml.min-1.cm2, the myocarditis group 0.019 +/- 0.004 ml.min-1.cm2, and the normal control 0.024 +/- 0.002 ml.min-1.cm2. The scanning area of collagen in the group with the drug was 2.06 +/- 0.77 mm, the myocarditis group 4.72 +/- 2.22 mm and the normal control 3.74 +/- 1.50 mm.

CONCLUSIONS

Collagen has increased in acute viral myocarditis, but its main role in this time is to repair the necrotic myocardium, and Losartan may block this process and make lesions develop. Therefore, the acute stage is not an practical period for intervening myocardial fibrosis in viral myocarditis.

Scattered radiation in scanning slot mammography

Monte Carlo simulations were used to quantify the amount of scattered radiation a scanning slot detector geometry designed for use in digital mammography. Ratios of the scatter to primary (S/P) x-ray photon energy absorbed in the detector were obtained for a Lucite phantom, and were investigated as a function of photon energy, phantom thickness, and slot detector width. Over a Lucite phantom thickness range of 2-6 cm, the S/P ratios range from about 0.10 to 0.17 for a 4 mm wide slot detector at the x-ray photon energies used in mammography. These ratios increased by a factor of approximately 1.8 when the slot width was increased to 10 mm. In general, 20 keV photons gave S/P ratios similar to those of a 30 kVp x-ray spectrum (Mo target + 30 microns Mo filtration). The use of a 3 cm air gap reduced the S/P ratios by a factor of between 2.5 and 3.4, depending on the phantom thickness. For a constant primary energy fluence, coherent scatter was reduced as photon energy increased, whereas Compton scatter increased with increasing photon energy. With no air gap, the contributions of coherent and Compton scatter were found to be equal at 25 keV, whereas the introduction of a 3 cm air gap resulted in equal contributions for the two scatter processes at 36 keV. A 10 mm wide slot detector consisting of a 36.7 mg/cm2 thick Gd2O2S:Tb phosphor screen was compared to an ideal detector absorbing all incident primary/scatter photons. Average differences in the S/P ratios for these two detectors were 7% with no air gap and approximately 4% with a 3 cm air gap. The results obtained in this study will assist in the design of an optimal slot detector for use in digital mammography.

[A study of genetic heterogeneity in Pfeiffer syndrome]

OBJECTIVE

To understand the molecular pathology of Pfeiffer syndrome.

METHODS

DNA from peripheral blood was examined in 4 families with Pfeiffer syndrome by SSCP-sequence analyses and PCR-restriction enzyme digestion.

RESULTS

The authors found the mutations of FGFR2 gene in two families, an A to G transition in the 3' acceptor splice site of intron 8 in a family, and Asp321 Ala substitution in exon 9 in another family. In addition, the mutation in exon 5 of FGFR1 gene (Pro252Arg) was found in a family.

CONCLUSION

These findings reveal the genetic heterogeneity of Pfeiffer syndrome and can help one understand the molecular mechanism of the disease.

[Endovascular exclusion of abdominal aortic aneurysm]

OBJECTIVE

To explore the indications, methods, manipulations, and problems of endovascular exclusion of abdominal aortic aneurysm (AAA).

METHOD

Under general anesthesia and dynamic supervision of DSA, an endovascular exclusion with a stent-graft complex of 11.0 cm x 2.6 cm was successfully performed on a 70-year-old man contraindicated for major open surgery with AAA of 10.0 cm x 6.0 cm and an AAA neck of 2.5 cm x 1.6 cm.

RESULT

The patient was up and about on the first postoperative day. Duplex scan (by the end of the first postoperative week) and CT (on the postoperative 20th day) revealed a completely excluded AAA by the stent-graft that was patent and had an inner diameter of 2.2-2.4 cm, without migration and torsion. The primary AAA sac was full of thrombi and no patent lumbar and inferior mesenteric arteries were observed. The external diameter of AAA was unchanged, renal and iliac arteries were all patent, but a micro-crevice between the proximal end of the stent-graft and the anterior wall of the AAA neck was revealed. Six months postoperative follow-up showed that the patient's abdominal pulsatile mass and the left lower extremity's claudication disappeared.

CONCLUSION

Endovascular exclusion of AAA is of great practical value.

[A comparative study on transabdominal versus retroperitoneal approach for abdominal aortic surgery]

OBJECTIVE

To retrospectively compare transabdominal with retroperitoneal approach to the aorta for infrarenal aortic reconstruction.

METHODS

From January 1988 to December 1996, Patients undergoing surgery for abdominal aortic aneurysm (AAA) or aortoiliac occlusive disease (AIOD) were included in the retrospective comparison of transabdominal approach (TAA) with retroperitoneal approach (RPA) for aortic surgery. Forty-four patients were analyzed, with 26 (23 with AAA and 3 with AIOD) in TAA group and 18 (16 with AAA and 2 with AIOD) in RPA group. There were no significant differences between the groups in terms of age, sex, comorbid conditions, and vascular graft anastomoses.

RESULTS

The incidence of intraoperative complications was similar for both groups. Postoperatively, RPA group had significantly fewer overall complications than TAA group (P < 0.01). The incidence of prolonged ileus (6 cases in TAA group, none in RPA group) and small bowel obstruction (2 cases in TAA group, none in RPA group) was higher in the TAA group (P < 0.01). Postoperatively four deaths occurred with two in each group. There was no difference in pulmonary complications (P = 0.70). In long-term follow-up (mean 32 months), no significant difference was found in incisional hernias in the two groups.

CONCLUSIONS

RPA approach, with fewer postoperative complications, short stay in the hospital and intensive care unit, is a safer and simpler approach for abdominal aortic surgery.

[Angioscopic in-situ arterial bypass for lower extremity revascularization]

The authors' initial experience of angioscopic in-situ arterial bypass of 37 extremities reveals that angioscopy can be used to assist complete valvular ablation and precise location and ligation of tributaries of saphenous vein grafts, avoiding postoperative arterial-venous fistula and warm ischemic injury to grafts. Angioscopy is also used to perform intraoperative completion inspection of the grafts and anastomoses. The designed biocomposite graft and common ostium technique promotes the usage rate of the limited autogenous vein grafts and enlarges the diameter of grafts and blood flow through the distal anastomosis. Because of the above new series of procedures, the extremity salvage rate in this study was 34/37 limbs. During the follow-up period of 2-18 months, all anastomoses were patent. The preoperative ankle and toe pressure of 3.5 +/- 0.2 kPa and 2.0 +/- 0.1 kPa respectively rose to 5.4 +/- 0.1 kPa and 3.8 +/- 0.2 kPa postoperatively. We conclude that angioscopic in-situ arterial bypass surgery is of practical value and specially advantageous in lower extremity revascularization.

[Effect of tetramethyl pyrazine on coronary vasoconstriction induced by endothelin-1 in dogs]

The purpose of this study was to determine the antagonistic effect of tetramethyl pyrazine (TMP), a sort of chinese herbal medicine, on coronary vasoconstriction induced by endothelin-1 (ET-1) in closed chest dogs. ET-1 at doses of 50, 75 and 100 pmol was selectively administered into left main coronary artery and coronary angiogram was performed in 1, 3 and 10 minutes after intracoronary administration of ET-1. After a 60 minute interval ET-1 administration and coronary angiogram were repeated in two groups in group A with 5 dogs intravenous infusion of saline solution was administered while in group B with 4 dogs TMP was infused at a dose of 80 mg/kg. Blood pressure of intra-femoral artery, heart rate and ECG were monitored during the experiment. The study demonstrated that coronary vessel diameter significantly decreased by 17% (P < 0.02) in group A and 20% (P < 0.02) in group B, associated with ischemia in ECG (4/5 in group A and 3/4 in group B) after intracoronary administration of ET-1. Endothelin-1 induced coronary vasoconstriction and ischemic changes in ECG were significantly inhibited by intravenous TMP. The coronary diameter increased by 20% (P < 0.03) after administration of TMP, comparing with the control group. Heart rate had an increased response to TMP. In conclusion this study demonstrated that intracoronary administration of ET-1 caused significant myocardial ischemia through coronary vasoconstriction, which was inhibited by TMP. TMP significantly dilated coronary artery.

Unintended consequences of immigration reform: discrimination and Hispanic employment

The record-keeping requirements of the Immigration Reform and Control Act(IRCA), and fines for illegal employment, may induce employers to discriminate against foreign-appearing workers. The General Accounting Office (GAO) reported widespread IRCA-related discrimination but did not link reported discriminatory practices to discriminatory employment behavior. We analyze the GAO's random survey and, controlling for selectivity effects, demonstrate that employers who report discriminatory practices actually employ fewer Hispanics. Although the measured reduction of Hispanic employment due to IRCA is fairly small, this finding parallels research alerting us to adverse consequences of a law that so far has achieved few of its intended effects.

[Comparative study of ultrasonic detection of popliteal vein reflux]

The venous valve undergoes more destruction and malfunction, and the quantity and duration of venous valvular reflux are larger and longer. On the basis of this mechanism, we detected the popliteal vein reflux duration and various influencing factors with duplex ultrasound. The reflux duration longer than 0.5 secand was verified as the evidence of primary venous insufficiency (PVI) in the detection of 40 cases. The detecting method recommended by us is that with standing position, and pneumatic compression 10. 67kPa (80mmHg) applied to calf, the reflux duration through popliteal venous valves is detected by using both pulsed-wave Doppler scanning and color-flow Doppler scanning. With the rates of sensitivity (92%), specificity (100%), and accuracy (94%), this noninvasive, quantitative, and easily handled method showed a very good diagnostic value.

Film density calibration for computed radiography systems: is the standard three-point procedure accurate?

With computed radiography (CR) systems, laser printer-film processor combinations are normally checked daily by using test film three-point density measurements. In this study, the authors show that the recommended three-point quality assurance procedure can show satisfactory results even though the CR film output behaves in an anomalous manner. This problem can be corrected by using a 16-point calibration procedure. Regular 16-point calibrations should be performed to ensure satisfactory CR system performance.