Biomedical subjects

A Roodt

Publications and source records attributed to A Roodt.

5 recordsLinked to original sources

PubMed2003

Calcium supplementation to prevent pre-eclampsia--a systematic review.

BACKGROUND: Calcium supplementation during pregnancy may prevent high blood pressure and preterm labour. OBJECTIVE: To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child adverse outcomes. DESIGN: A systematic review of randomised trials that compared supplementation with at least 1 g calcium daily during pregnancy with placebo. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register (October 2001) and the Cochrane Controlled Trials Register (Issue 3, 2001) were searched and study authors were contacted. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed. Data were extracted and analysed. MAIN RESULTS: There was a modest reduction in the risk of pre-eclampsia with calcium supplementation (relative risk (RR) 0.68, 95% confidence interval (CI): 0.57-0.81). The effect was greatest for women at high risk of hypertension (RR 0.21, 95% CI: 0.11-0.39) and those with low baseline calcium intake (RR 0.32, 95% CI: 0.21-0.49). There was no overall effect on the risk of preterm delivery, although there was a reduction in risk among women at high risk of hypertension (RR 0.42, 95% CI: 0.23-0.78). There was no evidence of any effect of calcium supplementation on stillbirth or death before discharge from hospital. There were fewer babies with birthweight < 2,500 g (RR 0.83, 95% CI: 0.71-0.98). In one study, childhood systolic blood pressure > 95th percentile was reduced (RR 0.59, 95% CI: 0.39-0.91). CONCLUSIONS: Calcium supplementation appears to be beneficial for women at high risk of gestational hypertension and in communities with low dietary calcium intake. These benefits were confined to several rather small trials, and were not found in the largest trial to date, conducted in a low-risk population. Further research is required.

Calcium↗

PubMed2001

trans-Diiodobis(1,3,5-triaza-7-phosphaadamantane)platinum(II).

The crystal structure of the title compound, trans-[PtI(2)(C(6)H(12)N(3)P)(2)], describes one of the few platinum(II) complexes containing two of the water-soluble 1,3,5-triaza-7-phosphaadamantane ligands reported to date. The complex crystallizes on an inversion centre with the most important bond lengths and angles being Pt-P 2.3128 (12) A, Pt-I 2.6022 (6) A, P-Pt-I 90.94 (3) degrees and P'-Pt-I 89.06 (3) degrees.

Journal Article↗

PubMed2000

Packing effects on the geometry of neutral platinum(II) complexes due to solvate molecules: the structures of trans-dichlorobis(triphenylarsine)-platinum(II)

A series of structures of trans-dichlorobis(triphenylarsine)platinum(II), recrystallized from four different solvents, have been characterized by X-ray crystallography and were shown to crystallize as different solvates (same metal complex, different crystallization solvents). Their geometric differences induced by packing and solvent molecules were analysed with half-normal probability plots and root-mean-square deviations. The recrystallization solvents used in the investigation were 1,1,1-trichloroethane, dichloromethane, 1,2-dichloroethane and benzene, and the following crystallization modes were obtained. From 1,1,1-trichloroethane the metal complex crystallizes without solvent as trans-[PtCl2(AsPh3)2] in P2(1)/n with Z = 2, a = 9.271 (2), b = 19.726 (4), c = 9.830 (2) A, beta = 111.83 (3)degrees, V = 1668.8 (6) A3, R = 0.0262, and from dichloromethane with two solvent molecules as trans-[PtC12(AsPh3)2].2CH2C12 in Pbca with Z= 4, a = 20.582 (4), b = 8.146 (2), c = 23.491 (5) A, V = 3938.5 (14) A3 and R = 0.0316. From dichloroethane it crystallizes with one solvent molecule as trans-[PtC12(AsPh3)2].C2H4C12 in P1 with Z = 1, a = 9.390 (2), b= 9.548 (2), c = 11.931 (2) A, alpha = 109.70 (3), beta = 108.26 (3), gamma = 98.77 (3) , V= 915.6 (3) A3, R = 0.0390, and from benzene with half a solvent molecule as trans- [PtC12(AsPh3)2].0.5C6H6 in P2(1)/n with Z = 4, a = 11.778 (2), b = 18.712 (4), c = 16.647 (3) A, beta = 104.78 (3) , V= 3547.3 (12) A3 and R = 0.0303. In all four compounds platinum(II) coordinates to triphenylarsine and chloride in a pseudo-square-planar trans configuration. The Pt-As distances are in the range 2.4104 (4)-2.3923 (4) A and the Pt-C distances are in the range 2.309 (2)-2.2839 (9) A. The solvents have a large influence on the packing, resulting in different space groups or different occupancies in the same space group. Half-normal probability plots show that the largest geometric differences, within the metal complex, are in the bond and torsion angles around the As-C bonds. Very similar torsion angles were observed around the Pt-As bond for all the structures, except for one AsPh3 ligand in the benzene solvate, which differs by about 10 from the others. The metal-donor bond distance varies by as much as 0.019 and 0.025 A (95% confidence interval) for Pt-As and Pt-C1, respectively. The variations are essentially caused by intermolecular interactions. Packing efficiency is expressed as the volume filled by each metal complex in the unit cell and is calculated by subtracting the sum of the solvent molecule volumes from the total volume of the unit cell and then dividing by Z. The efficiency is largest in the dichloroethane solvate and smallest in the non-solvated compound, with a difference of approximately 22 A3 per metal complex.

Journal Article↗

PubMed1997

Radiation dose estimates of 186Re-hydroxyethylidene diphosphonate for palliation of metastatic osseous lesions: an animal model study.

A common complication in patients with breast or prostate cancer is bone metastases causing pain. New radionuclide therapy methods have recently been proposed for palliation, including 186Re-hydroxyethylidene diphosphonate (186Re-HEDP). This paper reports on the local development of 186Re-HEDP and the biodistribution studied in animals for eventual use in patients. Adult dose was computed assuming a 70 kg standard man. The 186Re was labelled to HEDP using standard techniques. The biodistribution in five Chacma baboons (Papio ursinus) was studied. Doses ranging from 39.4 to 44.9 MBq kg(-1) (mean 43.6 +/- 2.8 MBq kg[-1]) were administered, corresponding to an adult human dose of 2960 MBq (80 mCi). Whole-body images of the animals were obtained with a dual-headed scintillation camera on an hourly basis for 6 h post-injection and then daily for 3 days. The bone, soft tissue, kidneys and urinary bladder were considered source organs and data from these organs were used in a compartmental model to obtain the mean residence times of the radionuclide in the different source organs. Radiation dose estimates for 186Re-HEDP were subsequently obtained with the MIRDOSE 3 program. The estimated absorbed radiation doses to some of the organs (expressed in mGy MBq[-l]) were as follows: bone surface 1.69; kidneys 0.09; liver 0.04; ovaries 0.04; red marrow 0.75; total body 0.12; urinary bladder wall 0.43. 186Re-HEDP yielded an effective dose of 0.17 mSv MBq(-1). The radiation dose delivered to the bone marrow in this study did not cause any detrimental effect to the baboons, indicating that locally produced 186Re-HEDP is suitable for clinical use.

Adult↗

PubMedDate not supplied

A two-year, single-group experience with rotational atherectomy.

Rotational atherectomy was introduced with a view to approaching percutaneously, cases that were suboptimal or unsuitable for conventional percutaneous transluminal coronary angioplasty (PTCA). In this article we present our findings for a period of two years starting in April 2001, when 60 procedures were performed on 54 patients. We found the procedure to be successful in B2 and C type lesions. It is our opinion that the lower burr-to-artery ratio used in our cases was significantly beneficial in decreasing immediate complications related to the procedure. Complimentary PTCA and stenting improved the angiographic end result. Using this strategy, we have achieved very acceptable clinical results.

Aged↗