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R S Lorenc

Publications and source records attributed to R S Lorenc.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Comparison of bone density in various skeletal parts in women during peri and postmenopause with previous Colles fracture].

Forearm fracture of Colles type is one of the most frequently observed osteoporotic fractures in women in postmenopausal period. It is proved that the group of women who had Celles fractures (n = 63) has lower bone mineral density in all measured sites except hip comparing to the controls (n = 53). Osteopenia found involves trabecular bone. Women with previous forearm fracture can be treated as the group of increased risk for spine and femoral neck fracture in the future.

Aged↗
PubMed1995

[Role of densitometric examination in diagnosis of osteoporosis].

Densitometric studies gain even wider acceptance in the monitoring, treatment and diagnosis of metabolic bone diseases. The paper includes a number of views on the ways of using densitometric equipment in screening for osteoporosis, and remarks on the interpretation of the obtained results.

Adult↗
PubMed1994

Reproducibility of a questionnaire on risk factors for osteoporosis in a multicentre prevalence survey: the European Vertebral Osteoporosis Study.

BACKGROUND: The European Vertebral Osteoporosis Study Group (EVOS) developed a questionnaire, back translated into 14 different European languages, for use in a multinational epidemiological study of vertebral osteoporosis. We investigated the reproducibility of this questionnaire in four of the participating study centres. METHODS: In all 151 men and women, aged 50-85 years, from Lubeck (Germany), Malmo (Sweden), Warsaw (Poland) and Oviedo (Northern Spain), were retested with the questionnaire on two occasions using a different observer within a 28-day period. RESULTS: Questions relating to personal or medical history were more reproducible than questions concerning subjective symptoms or aspects of lifestyle. The level of agreement for the non-ordinal categorical variables, as estimated by kappa, varied from 0.38 to 1.00 across the four centres. Agreement for the multicategory ordinal, mainly lifestyle, questions was in general poorer though improved when a weighted analysis was performed. For continuous data the 95% limits of agreement were narrow, and there was no evidence of bias between interviewers. There were no important differences in reproducibility across the four centres for either categorical or continuous data. CONCLUSION: The study indicates that the questionnaire may produce useful and comparable information concerning risk factors for osteoporosis across different countries and in different languages. It also highlights that questionnaire instruments designed for use in multinational population-based studies may provide data of comparable quality across a range of settings.

Aged↗
PubMed1994

Potential of densitometric measurement in selected pediatric subject.

On the aim to recognize bone mineral measurements as somatic development parameter as well as its clinical usefulness in pediatric clinic, the investigations with of DPX-L were performed. Material consisted of 302 healthy scholars both sex and 85 patients aged 6.0-18.9 yrs children diagnosed as idiopathic juvenile osteoporosis (IJO) and osteogenesis imperfecta (OI). Total body mineral density (TBBMD) was evaluated as developmental parameter in normal children population and utilized in differential diagnosis and monitoring of bone pathology in children with IJO and OI.

Absorptiometry, Photon↗
PubMed1993

Vitamin B-6 deficiency alters rat enterocyte calcium homeostasis but not duodenal transport.

Isolated enterocytes were used as differential transporting cells to examine calcium homeostasis in control and vitamin B-6-deficient rats. Kinetic analysis of calcium fluxes, as well as biochemical determinations, indicated that enterocytes from control animals had high concentrations of cytosol ionized calcium (318.5 +/- 22.4 nmol/L) and a large pool of exchangeable calcium (2.72 nmol/mg protein, or 86% of total cell calcium). Vitamin B-6 deficiency resulted in a 44% reduction in total cellular calcium (1.71 +/- 0.24 vs. 3.07 +/- 0.29 nmol/mg protein), a 69% reduction in total exchangeable calcium (0.85 vs. 2.72 nmol/mg protein) and a 56% reduction in cytosol ionized calcium concentration (141.4 +/- 13.5 vs. 318.5 +/- 22.4 nmol/L). Calcium fluxes between all cellular compartments were markedly diminished as a result of vitamin B-6 deficiency. However, vitamin B-6 deficiency did not affect the basic morphological or functional features of the enterocytes, such as cell viability, cell volume, membrane permeability and protein content. Moreover, intestinal calcium transport in vivo was not affected during vitamin B-6 deficiency, perhaps due to the greater paracellular ion movement compensating for the lower transcellular transport.

Animals↗
PubMed1993

[Evaluation of bone mass in children in a national sample of the population].

Dual energy X-ray absorptiometry (DEXA) was used to measure a mean bone mineral density (BMD) and bone mineral content (BMC) in total body and lumbar spine (L2-L4--BMD; L2-L4--BMC) in a group of 306 healthy children of both sexes, aged between 6 and 18 years. Step-wise increase in BMD in peripubertal age was noted. A degree of an increase in BMD at the age of 10 and 16 years was higher in boys than in girls. Bone mineral density of the spine was lower in the Polish population than that in USA. A high degree correlation between densitometric measurements and calendar age, and body height and weight was noted.

Absorptiometry, Photon↗
PubMed1993

[Dynamics of the course of idiopathic juvenile osteoporosis].

Clinical course of the idiopathic juvenile osteoporosis (IJO) was monitored in the group of 45 patients of both sexes with diagnosed disease, verified during follow-up period. The aim of the study was to evaluate the relationship between clinical symptoms and the results of biochemical, anthropometric, and densitometric measurements. An analysis of the obtained data enabled to distinguish the acute and chronic IJO phases. Evolution of the acute phase into chronic one was manifested by the cessation of pain and pathological gait stereotype, normalization of muscular strength, anthropometric parameters and urinary Pyr and DPyr excretion, as well as improvement in bone density. Hypercalciuria and increased urinary excretion of Pyr and DPyr, observed in the acute phase of IJO, may indicate that bone resorption exceeded bone formation. Tendency to maintain of alkaline phosphatase activity within lower limits of the normal values with slight increase during an improvement of densitometric parameters suggested transient osteoblast dysfunction.

Adolescent↗
PubMed1993

[Measurements of bone mineral density of the calcaneus in children with ultrasonic methods].

The study aimed at determining precision and accuracy of the ultrasound technique measuring bone mineral density in the calcaneus bone in children. Bone densitometer of Achilles type was adapted for measurements in children. Ultrasound beam was narrowed and a system of special pads positioning the foot were used for this purpose. Precision (CV (%) SOS: phantom 0.42, patients -0.42; BUA: phantom 1.46, patients -3.03) and accuracy of this technique were determined in comparison with dual energy X-ray absorptiometry as well as its value in diagnosis of osteopenia in childhood. An increase in SOS and BUA with the age was found. A decrease in these parameters was noted in children with osteopenia, comparing with the values in healthy children. Significant correlations (r ranging from 0.50 to 0.91) between ultrasound and DEXA techniques were seen. The results suggest that ultrasound technique might be useful in pediatric densitometry.

Absorptiometry, Photon↗
PubMed1993

[Evaluation of reproducibility and precision of ultrasonic measurements of the calcaneus for diagnosing osteopenia].

The study aimed at evaluating precision of ultrasound measurements of mineral bone density of the calcaneus, and evaluating correlation between the obtained results with those measured with single photon absorptiometry (SPA) and DEXA in different skeletal sites. In 24 healthy individuals and 44 patients with osteoporosis SOS, BUA, calcaneus stiffness index, spine bone mineral density (L2-L4), femoral neck and calcaneal bone mineral densities were measured with DEXA technique whereas BMD in distal radial bone was measured with SPA. Very good precision of ultrasound measurements--better for SOS (CV = 0.12%), worse for BUA (CV = 1.64%) due to repositioning--was achieved. Statistically significant correlation between ultrasound and DEXA measurements of BMD in calcaneus bone (r = 0.90), and significant but worse correlations with BMD measurements for the spine (r = 0.43), femoral bone neck (r = 0.53), and 1/3 radius, (r = 0.51) were achieved. Ultrasound measurements of bone mineral density have low error of repeatability and good accuracy, enabling to discriminate healthy individuals from osteoporosis patients.

Adult↗
PubMed1993

[Analysis of risk factors and prevalence of spinal osteoporosis in a population sample of Warsaw residents over 50 years of age].

Vertebral fractures are the one typically seen in osteoporosis. An incidence of vertebral body fractures and risk factors for osteoporosis were analysed in the retrospective population based epidemiological study. Population sample included 607 Warsaw inhabitants aged between 50 and 80 years (301 women and 306 men divided into age groups of 5 years, including approx. 50 subjects each). Vertebral body fractures were diagnosed on thoraco-lumbar spine X-rays made in the lateral projection. Risk factors for osteoporosis were analysed with the aid of an questionnaire. Bone mineral density was measured with dual energy X-ray absorptiometry and single photon absorptiometry in about 1/3 of the examined women. The prevalence of vertebral osteoporosis was high in both women (20.5%) and in men (27.8%). Low dietary calcium intake (below 800 mg daily) and low serum vitamin D levels (250HD less than 11 micrograms/ml) were characteristic for about 90% of the examined population. In osteoporotic subjects the following risk factors were significantly more frequent: age (p < 0.01), tobacco smoking (p < 0.001), low physical activity (p < 0.05), long-term immobilization (p < 0.01). Densitometry showed significantly lower bone mineral density in both women with vertebral fractures (p < 0.01) and low serum vitamin D levels (p < 0.05). Osteoporotic vertebral fractures were diagnosed more frequently in women with early menopause (p < 0.001). In the examined population there is a ligh prevalence of vertebral osteoporosis (predominating in mean) and risk factors.

Aged↗
PubMed1993

[Bone density in axial and peripheral skeleton and mineral density of the entire body as an age dependent factor in a population sample of healthy women].

Bone mineral density has been measured with dual energy X-ray absorptiometry (DEXA) in both axial and peripheral skeleton of 208 randomly selected healthy women aged between 20 and 80 years. Examined women have been stratified into the age groups of every 10 years. Bone mineral density has been measured in lumbar spine L2-L4 (AP), L2-L3 (Lat.) and proximal femur together with total body mineral density in every examined woman. The obtained results are considered reference values for the Polish population.

Absorptiometry, Photon↗
PubMed1993

[Pyridinoline and deoxypyridinoline excretion in urine of healthy children--dependence on age].

Pyridinoline (Pyr) and deoxypyridinoline (DPyr) are crosslinking compounds of bone collagen. Their urinary excretion is considered to be the first sensitive and specific marker of bone resorption in a number of metabolic bone diseases in adults. Application of crosslinks measurements to evaluate bone turnover rate in pediatric patients is so far limited because of lack of reference values. Therefore, the aim of our study was to determine urinary excretion of Pyr and DPyr in healthy children aged 3-18 yrs, and to evaluate the possible relationship between the levels of both compounds and body height, weight, BMC, and BMD. Pyr and DPyr levels were determined in first void urine samples obtained from 249 children (124 boys, 125 girls). Urine aliquots were hydrolysed, Pyr and DPyr extracted on CF1 cellulose, and analysed by HPLC with fluorimetric detection. Bone mineral content (BMC) and density (BMD) were measured with Lunar DPX-L apparatus in 205 children (104 boys, 101 girls) from the same population, aged over 5.5 yrs. In prepubertal children, a tendency towards lowering of urinary Pyr and DPyr levels with advancing age was shown. At puberty, urinary excretion of both crosslinks markedly decreased. This phenomenon was observed at various calendar age in girls as compared to boys, reflecting sex-dependent differences. Significant negative correlation (p < 0.0001) between urinary Pyr and DPyr levels and calendar age, body height and weight, BMC and BMD, were also found. The obtained results suggest that references values for Pyr and DPyr excretion in growing children should be related to calendar age, sex, and--in case of adolescents--phase of puberty.

Adolescent↗
PubMed1993

[Rehabilitation procedures for osteoporosis in children: practical advice].

The authors, basing on their own experience, propose rehabilitation program for osteoporotic children. Such a program may restore basic locomotive system functions in the period of time up to 12 weeks. Efficacy of the proposed rehabilitation program was evaluated with orthopaedic examination, X-ray, densitometry, and biochemical measurements in 210 children of both sexes who were followed-up for 3 years. The program includes motoric rehabilitation with specifically designed exercises. Basic exercises include active exercises without loading, isotonic resistive exercises and exercises in water whereas auxiliary program includes relaxing and active-passive exercises. The authors discuss rehabilitation priorities in osteoporosis such as the use of analgesics and early erect positioning. An effective rehabilitation requires, however, hospitalization.

Adolescent↗
PubMed1993

[Epidemiology of proximal femur fracture and results of therapy in patients treated at the Orthopedic-Trauma Ward of the Railway Hospital in Warsaw in the years 1986-1990].

A retrospective analysis included 441 hospitalized patients with fractures of the proximal femoral bone, treated at the orthopedic-traumatology ward in 1986-1990. Such patients constituted 9.12% of all patients treated during those years. There were 313 women aged between 26 and 99 years (mean 77.4 years) and 128 men aged between 30 and 95 years (mean 68.3 years). Fractures were more frequent in women than in men (rate 2.4:1). Four hundred four patients (91.6%) were treated surgically. Mortality rate in this group was about 10% whereas in patients treated conservatively--approximately 66%. Locomotive functions were restored in the majority of patients under 80 years of age. Mean hospitalization time was 22 days. Mean cost per patient in zlotys treated surgically was 4.97 million in 1990, and 8.3 million in 1992.

Adult↗
PubMed1991

Extremely low serum pyridoxal 5'-phosphate in children with familial hypophosphatemic rickets.

The apparent vitamin B-6 status of 31 children with familial hypophosphatemic rickets (FHR) was determined. All children had alkaline phosphatase activity that was high-normal to elevated for their ages. A sensitive assay for pyridoxal 5'-phosphate (PLP) indicated that 15 of the 31 children had an undetectable (less than 0.2 nmol/L) concentration of the vitamer--the lowest values yet reported in human serum. The 16 remaining children had concentrations of the vitamer so low that they indicated a potential severe vitamin B-6 deficiency. However, none of the children had ever presented with any of the classical vitamin B-6-deficiency symptoms. Treatment of three additional FHR children with 100 mg pyridoxine.HCl/d resulted in a moderate and transient elevation of their serum PLP concentrations, a dramatic elevation of their erythrocyte PLP concentrations, and no improvement in clinical condition. Serum or plasma PLP concentrations are an inappropriate index for determining vitamin B-6 status in people with FHR and perhaps in others with elevated alkaline phosphatase activity.

Adolescent↗
PubMed1989

Simplified HPLC method for quantitation of vitamin D in blood serum.

A single-step high performance liquid chromatography (HPLC) method for vitamin D quantitation in blood serum is described. Methanol/hexane extraction, silica Sep-Pak purification, differential dissolution, filtration, and the use of a precolumn in place of an injector sample loop allow for using only one (reversed phase) HPLC step instead of the usual two. Detection limit with the HPLC system used was about 1 micrograms/L of serum. Recovery of vitamin D3 added to serum ranged from 90% to 109%. Intra and interassay coefficient of variation values were 8.1% and 15.4%, respectively.

Cholecalciferol↗