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PubMed2004

Antimicrobial screening and quantitative determination of benzoic acid derivative of Gomphrena celosioides by TLC-densitometry.

The antimicrobial activity of ethanolic extract and pure compounds of Gomphrena celosioides have been screened by Kirby-Bauer method. Quantitative determination of 4-hydroxy-3-methoxy-benzoic acid in stems, leaves, flowers and roots was established by TLC-densitometry. Results showed significant activity against Staphylococcus aureus and Salmonella typhi. There were no significant differences in the determined benzoic acid derivative.

Amaranthaceae↗
PubMed1979

Bone densitometry using computed tomography. Part II: increased trabecular bone density in children with chronic renal failure.

The method of gamma-ray computed tomography (gamma-ray CT) bone densitometry described in the preceding article provides selective determination of trabecular bone density (TBD), the relative amount of compact bone (bone density, BD), and the total absorption (TA) within a bone cross section. Seven of nine children with chronic renal failure (CRF), and selected only on the basis of their serum creatinine value (greater than 5 mg/100 ml), had increased TBD values above the normal range, whereas the other bone mineral parameters were normal. Radiographic signs of secondary hyperparathyroidism (subperiosteal erosions, cysts) were reported in the five patients with the highest TBD values, whereas the subjective diagnosis of osteosclerosis reported in three of these five and in one other patient correlated less well with the TBD increases. However, this is the first report of an objective, non-invasive documentation of the radiological finding of osteosclerosis in CRF. It also explains why methods for bone mineral measurements used previously, such as a photon absorptiometry which provides only a parameter equivalent to TA, failed to reveal increases in bone mineral content in renal osteodystrophy even when signs of osteosclerosis were present. Thus, gamma-ray CT helps to document objectively the degree of osteosclerosis and its location.

Adolescent↗
PubMed1998

Simultaneous densitometry and quantitative bone sonography in the estimation of osteoporotic fracture risk.

759 post-menopausal women (41-80 years old), 175 with and 584 without vertebral fracture, were studied by quantitative bone sonography and densitometry of the distal radius in order to evaluate the ability of ultrasound transmission velocity (UTV) to separate fractured from healthy women independently of bone mineral density (BMD) and to test the possibility of improving the discriminant ability of BMD by the simultaneous use of UTV. A second BMD measurement was made at the mid radial shaft. Both BMD and UTV were higher in healthy subjects than in fractured women; the latter being older, shorter and having a longer postmenopausal status. On logistic regression, standardized for 1 SD from the mean value of healthy women, UTV differentiated between healthy and fractured subjects after correction for BMD. UTV was also a significant predictor of fracture in a selected subgroup of healthy and fractured women paired for BMD (144 pairs). In this same subgroup, the difference in UTV between fractured and healthy women regression lines was related to elasticity (E) variation between pairs. Simultaneously evaluating BMD and UTV as fracture predictors, logistic regression showed an odds ratio that was twice that of each predictor alone and 1.2 times higher than that derived from the simultaneous evaluation of two different BMD predictors. These data confirmed that UTV differentiates between healthy and fractured women both as well as and independent of BMD. In addition, UTV separated fractured from healthy BMD matched women by measuring non mass related differences. The simultaneous use of BMD and UTV improved the discriminant ability of each of them alone and of two simultaneous measurements of BMD detected at different skeletal sites.

Adult↗
PubMed1998

Linearity and accuracy errors in bone densitometry.

This investigation was undertaken to quantify accuracy errors and identify possible linearity errors in dual energy X-ray absorptiometry (DXA) of bone, based on studies of commercially available bone densitometers for planar densitometry. The following was found in a combination of in vitro phantom studies and in vivo investigations of human volunteers: (1) Pronounced differences between the instruments when measuring vertebral size and contours of the projected bone regions. (2) Falsely low bone mineral content (BMC in terms of g) in cases of low nominal bone mass, due to the fact that edge regions were omitted by the calculation software of some devices. (3) An increase in the projected bone area secondary to an increase in nominal bone mass with some instruments. (4) Clinically and statistically significant errors of accuracy of BMC and to a lesser extent bone mineral density (BMD). (5) Substantial linearity errors with some osteodensitometers for BMC, a phenomenon that reduces the usefulness of this parameter. It is concluded that DXA devices are affected by a combination of accuracy errors and linearity errors, some more than others, and that linearity errors influence their ability to monitor change in BMC and to a lesser extent in BMD, making system intercomparison difficult.

Adult↗
PubMed2004

Official positions of the International Society for Clinical Densitometry.

The International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences at which a panel of experts agreed on recommendations for performance and clinical applications of bone density testing. These recommendation were reviewed by the ISCD Board of Directors, and those approved by the board are now official positions of the ISCD. These include (1) indications for bone density testing, (2) reference databases for T-scores, (3) standards for performing central dual-energy X-ray absorptiometry (DXA) for diagnosis, (4) interpretation of peripheral bone density results, (5) diagnosis of osteoporosis in postmenopausal women, (6) diagnosis of osteoporosis in men, (7) diagnosis in premenopausal women, (8) diagnosis in children, (9) indications and interpretation for serial bone mass measurement, (10) technical standards for phantom scanning and calibration, (11) technical standards for cross-calibration of DXAsystems, and (12) standards for reporting of bone density results including correct nomenclature and preferred number of decimal digits.

Absorptiometry, Photon↗
PubMed1990

Determination of gangliosides in human cerebrospinal fluid by high-performance thin-layer chromatography and direct densitometry.

A method for the separation and quantification of a complex ganglioside mixture from a clinically available amount (5 ml) of human cerebrospinal fluid (CSF) is described. After reduction of the CSF volume by ultrafiltration, gangliosides are extracted with methanol/chloroform, then separated and quantified by high performance thin layer chromatography (HPTLC) and direct densitometry. For purification of crude ganglioside extract, the method of choice was microdialysis against water. Recovery for the present method including all methodological steps was 78%. No delective loss of gangliosides was demonstrated. The CSF ganglioside pattern from 'normal' CSF samples resembles that of brain gangliosides, particularly cerebellum gangliosides. Based on chromatographic comparison with standards, the percentages of lipid-bound NeuAc-positive fractions were: GM1 = II3NeuAc-GgOse4Cer (3%), GD3 = II3NeuAc2-Lac-Cer (3%), GD1a = IV3NeuAc,II3NeuAc-GgOse4Cer (15%), X1 (3%), GD1b = II3(NeuAc)2-GgOse4Cer (16%), X2 (3%), GT1b = IV3NeuAc,II3NeuAc2-GgOse4-Cer (41%), and GQ1b = IV3NeuAc2-,II3NeuAc2-GgOse4-Cer (16%). The total ganglioside content varied between 616-944 micrograms/l. Within-run and between-run assay precision (relative standard deviation) for 'normal' pooled CSF ranged from 0.04 to 0.12 for the predominant CSF ganglioside fractions (GD1a, GD1b, GT1b, GQ1b), and from 0.13 to 0.23 for the less pronounced fractions (GM1, GD3).

Adult↗
PubMed2006

Measurement of serum monoclonal components: comparison between densitometry and capillary zone electrophoresis.

Quantitative measurement of serum monoclonal protein (M-protein) is one of the most important tools for monitoring disease activity in monoclonal gammopathies. The aims of this study were to evaluate serum M-protein quantification by capillary zone electrophoresis (CZE) and to compare results with those obtained by densitometric scanning of high-resolution agarose gel electrophoresis (HRE-AGE). The evaluation was carried out on 82 samples from patients with various monoclonal gammopathies. All the suspected M-proteins were confirmed and characterised by immunofixation on agarose gel (IFE). CZE was performed on a Paragon CZE 2000 system (Beckman Coulter). Passing-Bablok regression was: y (CZE)=1.27 x(HRE-AGE)-5.21 g/L. The correlation coefficient was 0.92. Bland-Altman analysis demonstrated a mean difference of -1.83 g/L (95% CI -0.76 to -2.90) with clear evidence of a concentration-related bias. Densitometry gave higher values at low M-spikes (<20 g/L), whereas CZE gave higher values at large M-spikes (>20 g/L). The concentration-related bias was found to be independent of the immunoglobulin isotype. In conclusion, to compare previous results obtained by M-protein densitometric scanning with those obtained by direct measurement of CZE peaks, the calculation of a univocal transforming factor appears to be unreliable.

Antibodies, Monoclonal↗
PubMed2001

Effect of 17beta-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats.

The objective of the present study was to evaluate the effect of 17beta-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17beta-estradiol at a dose of 30 microg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17beta-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass.

Alendronate↗
PubMed2003

[Technology assessment in health care: bone densitometry and alternative therapies in post-menopausal osteoporosis].

This article briefly presents the target factors and methods for summarizing evidence employed in a technological evaluation, as well as the underlying logic in their elaboration and utilization in the field of public health. The example is post-menopausal osteoporosis, analyzing the current timeliness of disseminating bone densitometry and technologies to combat osteoporosis in Brazil Available studies on the effects of the respective technologies were reviewed according to the recommended methodology in order to produce a synthesis of the scientific evidence, updated and applied in Brazil. Preliminary cost-effective analyses of different alternatives for intervention (as compared to traditional care) are presented, considering women in and around menopause and at 65 years of age. Despite the optimistic hypotheses, the incremental cost estimates per averted fracture were high, all above R$ 10,000 for any of the various intervention alternatives, as compared to a mean cost of fractures treated by traditional care estimated at less than R$ 2,000, suggesting that the implementation of any of the target alternatives in the SUS would be questionable according to both efficiency criteria in the use of resources as well as equity.

Aged↗
PubMed2000

Effect of combined treatment with calcitonin on bone densitometry of patients with treated hypothyroidism.

INTRODUCTION: Thyroid hormones (TH) may affect bone metabolism and turnover, inducing a loss of bone mass among hyperthyroid and in hypothyroid patients under hormone replacement treatment. Thyroid dysfunction leads to changes in the dynamics of parathyroid hormone (PTH) and calcitonin (CT) secretion. OBJECTIVE: The objective of the study was to determine the usefulness of CT as adjuvant therapy in the prevention of bone loss during the treatment of hypothyroidism. MATERIAL AND METHODS: We studied 16 female patients with recently diagnosed primary hypothyroidism, divided into two groups: group G1 (n = 8) submitted to treatment with thyroxine (L-T4), and Group 2 (n = 8) that, in addition to being treated with L-T4, received a nasal CT spray. All patients were submitted to determination of TSH, free T4, bone mineral densitometry (BMD) and total bone calcium (TBC) at the time of diagnosis, after 6 to 9 months of treatment, and after 12 months of treatment. RESULTS: No statistical significant differences were detected in either group between the total BMD values obtained for the femur and lumbar spine before and after treatment. However, group G1 presented a statistical significant TBC loss after 12 months of treatment compared to initial values. In contrast, no TBC loss was observed in the group treated with LT-4 in combination with CT, a fact that may suggest that CT was responsible for the lower bone reabsorption during treatment of hypothyroidism.

Bone Density↗
PubMed1980

Measurement of tamoxifen in serum by thin-layer densitometry.

A method is described for the determination of tamoxifen in serum. The drug was extracted from the serum and separated from its metabolites by thin-layer chromatography. Irradiation of the thin-layer plate with ultra-violet light after development converted tamoxifen to a fluorescent product which could be estimated in situ by densitometry. The fluorescent product was identified as a substituted phenanthrene by thin-layer chromatography, and gas chromatography--mass spectrometry. The method allowed concentrations as low as 6.8 nmol/l serum to be measured. After an oral dose of tamoxifen (10 mg) to a female patient the maximum serum concentration (66.2 nmol/l) was achieved in 3 h. When 10 mg tamoxifen were taken twice daily for 21 days by the same patient serum concentrations of about 500 nmol/l were achieved.

Chromatography, Thin Layer↗
PubMed1999

[Densitometry for assessment of periacetabular bony changes after Parhofer-Mönch total hip replacement].

Densitometry for assessment of mineral changes after Parhofer-Mönch total hip replacement 10 mm around the acetabular component has been done in 53 patients (31 females and 22 males, mean age 52.1 years) with unilateral hip arthritis. Lunar DPX apparatus has been used, "manual analysis" of "Orthopedic" software and modification of DeLee and Charnley zones for DEXA technique was employed. After 6 months follow-up BMC and BMD decreased in all zones analyzed, especially in zone 2. These values increased in next 6 and 12 months but did not compensate for the primary loss.

Acetabulum↗
PubMedDate not supplied

Identification and assay of lamotrigine in human milk with gas chromatography and densitometry.

Conditions necessary for isolation and assay of lamotrigine in the human milk with gas chromatography in the range of concentrations 2-20 micrograms/ml, and densitometry in the range of 2-10 micrograms/ml are discussed. Lamotrigine was extracted with methylene chloride from the alkaline solution. In gas chromatography capillary column DB-17, flame-ionizing detector, and octacozanole as the internal standard have been used. Densitometric measurements have been performed at 217 nm.

Anticonvulsants↗
PubMed2000

[Clinical evaluation of hepatic blood flow and oxygen metabolism during thoracoabdominal aortic surgery using pulse dye-densitometry combined with hepatic venous oxygen saturation].

OBJECTIVE: There has been no report that pulse dye-densitometry (PDD), a novel non-invasive modality for monitoring hepatic blood flow (HBF), was applied during cardio-pulmonary bypass (CPB). We investigated weather PDD was useful to measure HBF during thoracoabdominal aortic surgery using partial CPB. Furthermore, HBF and hepatic metabolism were assessed during selective visceral perfusion or shunt using PDD, hepatic venous oxygen saturation (ShO2), and analysis of hepatic metabolic products. METHODS: A prospective study was carried out in eight patients who underwent thoracoabdominal aortic surgery from April 1998 to October 1999. Operative adjuncts were partial CPB with mild hypothermia in six (femoral veno-arterial bypass: FF group) and deep hypothermic circulatory arrest in two (DHCA group). Measurements were performed at following five time points; just before initiating CPB, just after establishing CPB, during selective visceral perfusion, during selective visceral shunt, and just after weaning CPB. RESULTS: Plasma clearance rate of indocyanine green measured by PDD well correlated with that obtained by in vitro spectrophotometry (p < 0.0001, R2 = 0.644). PDD demonstrated that decreased IIBF during selective visceral perfusion or shunt was well compensated by increased hepatic oxygen extraction rate in FF group and reduced oxygen consumption in DHCA group. Lactic acid extraction ratio and arterial ketone body ratio also decreased during this period. ShO2 during selective visceral shunt correlated with systemic systolic arterial pressure (SAP), and it showed a marked decrease under 20% when SAP was below 80 mmHg. Postoperative time course of serum total bilirubin and alanine aminotransferase of almost patients were within acceptable limits except the patient who required large amount of homologous blood transfusion. CONCLUSIONS: PDD proved to be a useful modality that enabled non-invasive monitoring of HBF even during partial CPB. Decreased HBF during selective visceral perfusion or shunt in thoracoabdominal aortic surgery was within physiological compensation, which led us conclude that it might be effective adjuncts, for visceral organ protection.

Adult↗
PubMed2000

[Technical improvements in bone densitometry].

The SBU-report no 127 "Mätning av bentäthet" [Measuring bone density] was published in 1995 and its conclusions are still valid. However, since then new treatment modalities have placed increasing demands on the diagnostic capability and performance of the apparatus used for bone densitometry. The most well-established and widely used technique for bone mineral determination is dual energy X-ray absorptiometry. Several international studies have shown that quantitative ultrasound should not be used for diagnosis or monitoring of osteoporosis. The reproducibility of one's method is important for monitoring, and the method's accuracy is important for diagnosis. Due to the limitations of the techniques and the slow turnover of the skeleton, repeated measurements are not meaningful until at least two years have passed. In order to maintain high quality in measurement results it is important to have trained personnel and to have a regular quality assurance program for the apparatus.

Absorptiometry, Photon↗
PubMed2000

[Bone densitometry and uterine size: a practical relationship for climacteric women].

BACKGROUND: Double beam bone densitometry allows to select climacteric women who will benefit from hormone replacement. However, it is not always affordable in clinical practice. AIM: To study possible alternative markers of bone mineral density. PATIENTS AND METHODS: A retrospective survey of climacteric women in whom bone mineral density was measured when hormone replacement therapy was started. Eighty one women were studied and in 27, uterine size index was obtained from pelvic ultrasound examinations. Women with and without uterine size index measurements were analyzed separately. Relationships of bone mineral density with age, lapse from menopause, body mass index and uterine size index were sought. RESULTS: There was a significant regression between the lapse in years from menopause and lumbar bone mineral density in the group without uterine size index measurements (r2 = 0.228, ANOVA p = 0.014). There was also a significant regression of lumbar bone mineral density with the uterine size index (r2 = 0.236, ANOVA p = 0.01) in those women in whom this measurement was available. No other variables were associated with bone mineral density. CONCLUSION: In this group of patients, the lapse after menopause and uterine size index are predictors of lumbar bone mineral density (Rev Méd Chile 2000; 128: 1127-31).

Adult↗
PubMedDate not supplied

Selective separation and simultaneous determination of trace levels of five types of fluorinated quinolone drugs by thin-layer chromatography/fluorescence densitometry.

This paper reports the determination of trace levels of 5 types of fluorinated quinolone drugs, i.e., ciprofloxacin, norfloxacin, enoxacin, pefloxacin, and ofloxacin, by thin-layer chromatography (TLC)/fluorescence densitometry. The new analytical method uses 2-step TLC development, selective separation, and simultaneous determination of the 5 drugs. The method was also applied to the determination of recoveries of standards of the 5 drugs in plasma and urine samples. The results show that the method has a wide linear range, high repeatability, and good stability.

Anti-Infective Agents↗
PubMed1975

Quantitative determination of drugs by means of densitometry of thin-layer chromatograms. Part 4: Determination of vitamins A and E in pharmaceutical preparations.

A quantitative method for the determination of vitamins A and E is proposed based on the direct densitometry of thinlayer chromatographic spots. An appropriate solvent system for the chromatographic separation of the vitamins and the conditions under which a linear relationship between the absorbed light and the logarithm of concentration exists (1--10 mug range) are found. The precision of the method is evaluated by a statistical treatment of the results. Satisfactory reproducibility is established-- the variation coefficient for the determination of the two vitamins is about 4--5%. The method is applied for the analysis of oil and aqueous injection solutions, mixtures containing the three vitamins A, E and D2 and some pharmaceutical preparations (Pharmavit¿ and Devitforte¿). The presence of the decomposition products and other substances (other pharmaceuticals, stabilizers, solubilizers etc.) does not affect the determination. The analysis is performed without preliminary treatment of the sample.

Chromatography, Thin Layer↗