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Biomedical subjects

A Schlemmer

Publications and source records attributed to A Schlemmer.

At least 19 recordsLinked to original sources
PubMed2006

The effects of a language barrier in a South African district hospital.

BACKGROUND: Communication between health workers and patients at Hottentots Holland Hospital (HHH) is hindered by staff and patients not speaking the same language. HHH is a district hospital in the Cape Town Metropolitan District of the Western Cape where staff mainly speak Afrikaans or English and a large number of patients mainly Xhosa. OBJECTIVES: The study aimed to explore the effects of this language barrier on health workers and patients at HHH. DESIGN: Three focus group interviews were held with 21 members of staff and 5 in-depth patient interviews were conducted. RESULTS: The language barrier was found to interfere with working efficiently, create uncertainty about the accuracy of interpretation, be enhanced by a lack of education or training, cause significant ethical dilemmas, negatively influence the attitudes of patients and staff towards each other, decrease the quality of and satisfaction with care, and cause cross-cultural misunderstandings. CONCLUSION: The effects of the language barrier were considerable and persistent despite an official language policy in the province. The training and employment of professional interpreters as well as teaching of basic Xhosa to staff are recommended.

Communication Barriers↗
PubMed2002

Circadian variation in the serum concentration of C-terminal telopeptide of type I collagen (serum CTx): effects of gender, age, menopausal status, posture, daylight, serum cortisol, and fasting.

We examined the diurnal variation in serum concentration of C-terminal telopeptide of type I collagen (serum CrossLaps, sCTx) under various conditions. The studies included a total of 100 individuals. Blood samples were collected every 3 h over 27 h. sCTx levels varied over the 24 h with a maximum at about 05:00 in the morning and a minimum of about 14:00 in the afternoon. The variation had a magnitude of about +/-40% around the 24 h mean and was similar in premenopausal and early and late postmenopausal women with normal and low bone mass. Furthermore, it was not affected by 5 days of bed-rest, by absence of a normal diurnal variation in cortisol production, or by absence of a normal light cycle (blindness). Nasal salmon calcitonin, an antiresorptive drug used for treatment of osteoporosis, was not able to break the circadian pattern whether the treatment was administered in the morning or the evening. The only parameter that showed a pronounced influence on the circadian variation was fasting, which reduced the variation significantly to about one fourth. From a practical point of view the results of this study demonstrate that samples for sCTx should be taken in the fasting state.

Adult↗
PubMed1999

Acute fasting diminishes the circadian rhythm of biochemical markers of bone resorption.

OBJECTIVE: Biochemical markers of bone turnover exhibit circadian rhythms with the peak during the night/early morning and the nadir in the late afternoon. The nocturnal increase in bone resorption could theoretically be caused by the absence of food consumption which brings about a decrease in net calcium absorption and an increase in parathyroid hormone (PTH), followed by increased bone resorption in response to the body's demand for calcium. The aim of the present study was to assess the influence of a 33-h fast on the circadian variation in biochemical markers of bone turnover. DESIGN: Eleven healthy premenopausal women (age: 24+/-5 years) participated in a randomised, cross-over study consisting of two periods: either 33h of fasting (fasting) followed 1 week later by a 33-h period with regular meals eaten at 0800-0830h, 1130-1230h and 1800-1900h (control) or vice versa. METHODS: Urinary CrossLaps (U-CL/Cr) corrected with creatinine, as a marker of bone resorption; serum osteocalcin (sOC) as a marker of bone formation; serum intact PTH (iPTH); serum phosphate; and serum calcium corrected with albumin. RESULTS: Both the fasting and the control periods showed a significant circadian rhythm in U-CL/Cr (P<0.001), but the decrease was significantly less pronounced in the morning hours during the fasting period. Fasting resulted in a significant decrease in serum iPTH (throughout the study period) as compared with the control period (P<0.05-0.001). No change was observed in sOC by fasting. CONCLUSION: Food consumption has a small influence on the circadian variation in bone resorption, independent of PTH. The fall in iPTH during fasting may be secondary to an increased bone resorption produced by fasting.

Adult↗
PubMed1997

Morning or evening administration of nasal calcitonin? Effects on biochemical markers of bone turnover.

The purpose of this study was to examine the effect of intranasal salmon calcitonin (sCT) administration (200 IE), given either in the morning (8:00) or evening (21:00), on the known circadian variation in biochemical markers of bone turnover. An open, placebo-controlled, randomized, crossover study, with three 24 h studies of blood samples drawn every third hour and urine collected in 3 h aliquots was undertaken. Subjects consisted of nine healthy postmenopausal women, aged 58 +/- 7 years. Urinary CrossLaps (a measure of bone resorption) was measured by ELISA and corrected for creatinine (Cr). Serum osteocalcin (sOC) was measured by radioimmunoassay (RIA). The first 24 h study was performed without intervention. Prior to this control study the participants were randomized to either morning (8:00) or evening (21:00) sCT (200 IE). sCT administrations were given 4-5 days prior to and during the second study. After a washing-out period of 2 weeks the participants were given 200 IE of sCT at the reverse time of the day 5 days prior to and during the third study. At all timepoints, urinary CrossLaps/Cr exhibited a significant (p < 0.001) circadian rhythm with its zenith in early morning and nadir in late afternoon. Both morning and evening administration of sCT significantly decreased the urinary excretion of CrossLaps/Cr approximately 3-6 h after administration with a subsequent rebound effect. sOC did not exhibit a significant circadian variation and was not affected by the calcitonin. The 24 h mean urinary CrossLaps/Cr and sOC remained unchanged. Both morning and evening sCT significantly decreased the urinary excretion of CrossLaps/Cr 3-6 h after administration, with a rebound effect approximately 12 h later. However, the present study does not indicate that neither evening nor twice-daily administration is superior to morning administration.

Administration, Intranasal↗
PubMed1997

Circadian variation in bone resorption is not related to serum cortisol.

Serum osteocalcin, serum procollagen type I carboxyterminal propeptide (sPICP), and the urinary excretion of pyridinium crosslinks (biochemical markers of bone formation and resorption) all exhibit a circadian variation with a peak during the night. This study was performed to investigate the influence of the endogenous circadian rhythm in cortisol on the biochemical markers of bone turnover. Participants included 11 patients substituted with hydrocortisone due to either hypopituitarism (n = 7) or bilateral adrenalectomy (n = 4). Their daily tablet intake of hydrocortisone was divided in four equal doses in order to abrogate the known circadian variation in cortisol. 24 healthy postmenopausal women served as controls. The study design was performed over 24 h, with blood samples taken every 3 h, and urine collected in 3 h aliquots. Urinary pyridinium crosslinks (Pyr/ Cr, D-Pyr/Cr), serum osteocalcin (sOC), and serum PICP were measured. Patients without a circadian variation in cortisol had normal circadian variation in the urinary excretion of pyridinium crosslinks and sPICP, but no circadian rhythm in serum osteocalcin. We conclude that the etiology of the circadian rhythm in the biochemical markers of bone turnover is still unknown. This study indicates that the circadian variation in sOC can be controlled by the endogenous circadian variation in serum cortisol, whereas this hormone does not control the circadian variation in either the serum PICP or the urinary excretion in pyridinium crosslinks.

Adrenalectomy↗
PubMed1995

Circadian rhythm in type I collagen formation in postmenopausal women with and without osteopenia.

A circadian rhythm in the serum concentration of the procollagen type I carboxyl-terminal propeptide (sPICP) has previously been demonstrated in premenopausal women. This study was performed to investigate the circadian rhythm in sPICP in healthy and osteopenic postmenopausal women. Blood samples were taken every third hour for 27 h from three groups of women: 12 early postmenopausal women (aged 55 +/- 2 years; mean +/- SD); 12 late postmenopausal women (aged 73 +/- 1 years); and 12 osteopenic but otherwise healthy late postmenopausal women (aged 73 +/- 1 years). A circadian rhythm in sPICP was found in all three groups, as shown by cosinor analysis (p = 0.000003-0.03). The circadian rhythm in sPICP was significantly different between the osteopenic group and the age-matched healthy group (p < 0.008). The amplitude of the circadian rhythm in sPICP was about twice as high in the osteopenic group, and the time of the maximum tended to be about 3 h later, as compared with the age-matched healthy group. The plasma concentration of osteocalcin, as measured by a recently developed two-site enzyme-linked immunosorbent assay, also showed a circadian rhythm in all three groups (p = 0.0001-0.05), with no significant differences between groups. In conclusion, we have found a significant circadian rhythm in sPICP in both early and late postmenopausal women. In osteopenic women the nightly peak in sPICP is larger and persists later into the night as compared with non-osteopenic women.

Aged↗
PubMed1995

Changes in the carboxyl-terminal propeptide of type I procollagen and other markers of bone formation upon five days of bed rest.

This study was performed in order to investigate the influence of skeletal unloading on the serum concentration of the carboxyl-terminal propeptide of type I procollagen (sPICP) and other markers of bone formation. Blood samples were taken every third hour from nine healthy premenopausal women (22-29 years) in two 24 h studies, before and at the end of five days of bed rest. Furthermore, a set of samples were taken 12 h apart after three days of bed rest. We measured sPICP, the serum concentration of intact and N-terminal-Mid fragment osteocalcin (sOC), and the serum concentration of alkaline phosphatase (sAP). During the five days of bed rest a gradual increase in sOC was observed, while sPICP gradually decreased. sAP was unchanged. Five days of best rest resulted in the following overall changes in the 24 h mean values: sPICP: -14% (p = 0.002); sOC: +9% (p = 0.009); sAP: -1% (not significant). The circadian patterns did not change significantly after bed rest. It is puzzling that the changes in the bone formation markers are of different magnitude, and for sPICP and sOC even in opposite directions. The increase in sOC may be caused by an increase in OC secretion by the osteoblasts or a release of bone-incorporated OC from resorbing sites; the accompanying decrease in sPICP may indicate that bone formation is actually transiently decreased after short term bed rest.

Adult↗
PubMed1994

Posture, age, menopause, and osteopenia do not influence the circadian variation in the urinary excretion of pyridinium crosslinks.

This study was performed to investigate whether the circadian variation in urinary pyridinium crosslinks is related to physical activity, age, the menopause, and asymptomatic osteopenia. We measured urinary pyridinoline/creatinine (Pyr/Cr) and deoxypyridinoline/creatinine (D-Pyr/Cr) in 9 healthy premenopausal women in two 27 h studies, before and at the end of 5 days of total bed rest. Both Pyr/Cr and D-Pyr/Cr showed highly significant circadian variations, with the peak at night and the nadir during the day (p < 0.001). The 5 days of complete bed rest produced no changes in the circadian pattern, but a general increase of 28% was observed in pyridinium crosslinks. A group of 12 healthy, early postmenopausal women (aged 55 +/- 2 years), 12 healthy, elderly postmenopausal women (aged 73 +/- 1 years), and 12 elderly osteopenic but otherwise healthy women (aged 73 +/- 1 years) were also studied for 27 h. All three groups showed highly significant (p < or = 0.001) circadian variations in the urinary excretion of pyridinium crosslinks. As expected, both Pyr/Cr (p < 0.05) and D-Pyr/Cr (p < 0.001) increased at the time of menopause, but the circadian variations in Pyr/Cr and D-Pyr/Cr were similar in all groups studied. We conclude that the circadian variation in the urinary excretion of pyridinium crosslinks is independent of physical factors. Furthermore, the circadian variation in pyridinium crosslinks was not related to age, menopausal status, or asymptomatic osteopenia.

Adult↗
PubMed1994

Urinary excretion of pyridinium cross-links in healthy women; the long-term effects of menopause and oestrogen/progesterone therapy.

OBJECTIVES: We investigated the effect of the menopause when followed longitudinally for a decade to evaluate whether women with an increased bone loss continue to have elevated urinary excretion of pyridinium cross-links later in menopause. Furthermore, we investigated the effect of oestrogen/progesterone therapy on the urinary excretion of pyridinium cross-links. PARTICIPANTS: In the cross-sectional study: 18 healthy premenopausal, 142 healthy post-menopausal women and 41 osteopenic post-menopausal women. In the longitudinal study: 45 healthy post-menopausal women followed up for 7-10 years after the menopause; these women were further divided into two equal groups, according to their loss of forearm bone mineral content over 2 years. In the oestradiol/progesterone double-blind, placebo-controlled 2-year trial: early post-menopausal women were given either hormone replacement therapy (n = 38) or placebo (n = 16). MEASUREMENTS: The urinary excretion of pyridinoline/creatinine (Pyr/Cr) and urinary deoxypyridinoline/creatinine (D-Pyr/Cr), two new markers of bone resorption. RESULTS: Pyr/Cr and D-Pyr/Cr increased significantly after the menopause (Pyr/Cr, 77%; D-Pyr/Cr, 98%, P < 0.001). Hormone replacement therapy reversed this increase towards premenopausal levels. Both pyridinium cross-links remained fairly constant during the first decade of the menopause, when measured in the longitudinal study. When the women were divided according to loss in forearm BMC, those with a loss greater than 3.5%/2 years had significantly higher levels of pyridinium cross-links (P < 0.05-0.01). Furthermore, both Pyr/Cr and D-Pyr/Cr were significantly higher in elderly osteopenic women (aged 68-72 years) than in age-matched non-osteopenic women (P < 0.01-0.001). CONCLUSIONS: Both Pyr/Cr and D-Pyr/Cr, two new markers of bone resorption, increased significantly at the time of the menopause, thereafter remaining fairly constant during the first post-menopausal decade. Women with increased bone loss continue to have elevated urinary excretion of pyridinium cross-links during the first decade of the menopause. This post-menopausal change is reversed by hormone replacement therapy to the premenopausal level.

Adult↗
PubMed1993

Possible variation in bone resorption during the normal menstrual cycle.

In order to determine whether bone turnover varies during the normal menstrual cycle, we measured biochemical markers of bone resorption (serum pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (sICTP), fasting urinary hydroxyproline/creatinine, fasting urinary pyridinoline/creatinine and fasting urinary deoxypyridinoline/creatinine) and bone formation (plasma osteocalcin, serum carboxy-terminal propeptide of type I procollagen and serum alkaline phosphatase) in ten healthy premenopausal women every two or three days for a complete menstrual cycle. A cyclic pattern was detected in sICTP, with its nadir during the follicular phase and its peak during the luteal phase, and an overall variation of 17% during the menstrual cycle (p = 0.004). No cyclic changes were observed in the urinary parameters of bone resorption or in the biochemical markers of bone formation. We conclude that sICTP, a new biochemical marker of bone resorption, undergoes small variations during a normal menstrual cycle in premenopausal women, whereas the biochemical markers of bone formation remain constant.

Adult↗
PubMed1992

Marked diurnal variation in urinary excretion of pyridinium cross-links in premenopausal women.

To investigate whether bone resorption exhibits a diurnal variation in healthy premenopausal women, we measured urinary excretion of pyridinoline and deoxypyridinoline cross-links (U-Pyr/Cr and U-D-Pyr/Cr) every 3 h over a 24-h period in 12 healthy premenopausal women (mean +/- 1 SD age, 32 +/- 5 yr). To study diurnal variation, U-Pyr/Cr and U-D-Pyr/Cr are the best available markers of bone resorption for a diurnal variation study, as they are not influenced by diet. Plasma osteocalcin and serum alkaline phosphatase (markers of bone formation) were also measured. A marked diurnal rhythm was observed in U-Pyr/Cr and U-D-Pyr/Cr, with the peak between 0500-0800 h and the nadir between 1400-2300 h. The fluctuation was 2-fold over the 24-h period, with a mean fall of 25-35% between 0800-1100 h. This study demonstrates a marked diurnal variation in the new biochemical markers of bone resorption, U-Pyr/Cr and U-D-Pyr/Cr, in premenopausal women. Furthermore, this study emphasizes the importance of regulating the time of the urine sample taken for measuring urinary pyridinium cross-links for clinical investigations as well as in clinical practice.

Adult↗
PubMed1991

Urinary excretion of pyridinoline crosslinks correlates with bone turnover measured on iliac crest biopsy in patients with vertebral osteoporosis.

Vertebral osteoporosis, a common disorder in elderly women, is characterized by a wide spectrum of bone turnover abnormalities on iliac crest biopsy. The level of bone formation can be assessed noninvasively by measuring serum osteocalcin, whereas conventional biochemical markers of bone resorption lack specificity and do not reflect bone resorption assessed from histology. We measured the urinary excretion of pyridinoline crosslinks Pyr and D-Pyr, a specific marker of bone and cartilage collagen degradation, along with serum osteocalcin and urinary hydroxyproline, in 36 elderly women with vertebral osteoporosis who had a simultaneous iliac crest biopsy. Urinary pyridinoline crosslinks, but not hydroxyproline, correlated significantly with histologic resorption, assessed by the osteoclast surface (r = 0.35, p less than 0.05 for Pyr; r = 0.46, p less than 0.01 for D-Pyr). In addition, Pyr and D-Pyr were correlated with the bone formation rate as well as serum osteocalcin, with correlation coefficients ranging from 0.69 to 0.80, p less than 0.0001. These data indicate that Pyr and D-Pyr are sensitive markers of bone turnover in elderly women with vertebral osteoporosis. The poor correlation between the level of urinary collagen crosslinks and histological assessment of bone resorption indicates the low sensitivity of iliac crest histomorphometry in the measurement of resorption rate of the skeleton.

Aged↗
PubMed1991

The effect of growth hormone (GH) therapy on urinary pyridinoline cross-links in GH-deficient adults.

OBJECTIVE: The aim was to study the effect of growth hormone (GH) on new markers of bone resorption (fasting urinary excretion of pyridinium cross-links (pyridinoline and deoxypyridinoline)) in GH-deficient adults. DESIGN: Randomized, double-blind, placebo-controlled cross-over study. The treatment periods (GH 2 IU/m2 subcutaneously, or placebo daily for 4 months) were separated by a 4-month washout period. PATIENTS: Twenty GH-deficient adults (aged 18-39). MEASUREMENTS: Blood and fasting urine samples were collected at the end of each 4-month treatment period. Plasma bone Gla protein was measured by radioimmunoassay and urine pyridinoline and deoxypyridinoline were measured by spectrofluorometry after high performance liquid chromatography and corrected for urinary creatinine. RESULTS: GH increased fasting urinary excretion of pyridinoline (287 +/- 123%, P less than 0.001) and deoxypyridinoline (313 +/- 140%, P less than 0.001). The GH-induced increment in these parameters correlated with the increase seen in plasma bone Gla protein (r = 0.83-0.86, P less than 0.001). CONCLUSION: Four months of GH substitution in GH-deficient adults increases bone resorption as well as bone formation. The effect on bone mass has yet to be assessed.

Adolescent↗
PubMed1991

Effect of menopause and hormone replacement therapy on the urinary excretion of pyridinium cross-links.

Pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) are two cross-links of collagen molecules that are present in the extracellular matrix and released during its degradation. In contrast to the wide distribution of collagen, Pyr is present in bone and cartilage, but not in significant amounts in other connective tissues, and D-Pyr appears to be specific for bone tissue. Therefore, the urinary excretion of Pyr and D-Pyr might be a sensitive marker of bone matrix degradation. Using a specific high pressure liquid chromatography assay we have measured Pyr and D-Pyr cross-links in a 24-h and a fasting urine sample in 60 early postmenopausal women and 19 premenopausal women matched for age. Menopause induced a 62% increase in Fu Pyr (49.8 +/- 18.7 vs. 30.8 +/- 8.0 pmol/mumol creatinine; P less than 0.001) and an 82% increase in Fu D-Pyr (8.2 +/- 3.4 vs. 4.5 +/- 1.4 pmol/mumol creatinine; P less than 0.001). In 20 postmenopausal women on hormone replacement therapy, urinary Pyr and D-Pyr returned to premenopausal levels within 6 months, contrasting with unchanged levels during placebo treatment. The 24-h excretion of Pyr and D-Pyr was significantly lower than the fasting excretion, but was similarly decreased after hormone replacement therapy. Pyr and D-Pyr excretion measured in the same urinary sample were highly correlated (r = 0.85 for fasting and 0.83 for 24-h sampling), but correlations between fasting and 24-h values were weak (D-Pyr, r = 0.30; Pyr, r = 0.29; P less than 0.05 for both). Correlations between urinary cross-links and other markers of bone turnover (Fu hydroxyproline/creatinine and plasma osteocalcin) were significant but low (Pyr vs. osteocalcin, r = 0.29, P less than 0.05; Pyr vs. hydroxyproline, r = 0/.34; P less than 0.01; D-Pyr vs. osteocalcin, r = 0.39; P less than 0.01), except for D-Pyr vs. hydroxyproline (r = 0.24; P = 0.07), suggesting that these markers reflect different events of bone metabolism. Finally, a single measurement of the fasting excretion, but not of the 24-h excretion, of cross-links was significantly correlated (Pyr, r = 0.34; P less than 0.05; D-Pyr, r = -0.46; P less than 0.01), with the subsequent spontaneous rate of bone loss assessed by repeated measurements of the radial bone mineral content in 37 postmenopausal women.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1990

Influence of smoking, body fat distribution, and alcohol consumption on serum lipids, lipoproteins, and apolipoproteins in early postmenopausal women.

The impact of smoking, alcohol consumption, obesity, and body fat distribution (measured either directly by dual photon absorptiometry as abdominal fat% (AF%) or as the waist-to-hip ratio (WTH] on serum lipids, lipoproteins, and apolipoproteins was investigated in 148 early postmenopausal women. All the women were healthy and none were taking medication known to influence the parameters studied. Smokers had significantly higher levels of triglycerides, low density lipoprotein cholesterol (LDL-C), and apolipoprotein B (P less than 0.05), and higher ratios of LDL-C/HDL-C and apolipoprotein B/A-I (P less than 0.01), but lower levels of high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (P less than 0.01). Moderate alcohol consumption was positively associated with HDL-C and apolipoprotein A-I (P less than 0.001). Body weight and body mass index (BMI) tended to be positively associated with an atherogenic lipoprotein and apolipoprotein profile. However, body fat distribution parameters (AF% and WTH) were stronger predictors of lipoproteins and apolipoproteins than were body weight and BMI, which did not seem to be independent predictors of lipoproteins and apolipoproteins. We conclude that cigarette smoking and a central fat distribution have a significant, independent, negative influence on lipids, lipoproteins, and apolipoproteins, whereas moderate alcohol consumption has a positive effect on these parameters in early postmenopausal women.

Adipose Tissue↗
PubMed1990

Smoking induces increased androgen levels in early post-menopausal women.

In order to clarify the effect of smoking on androgen status in the early post-menopause we examined 267 women aged 45-54 years, of whom 146 (55%) were smokers. The cigarette smokers had a significantly higher serum concentration of androstenedione (P less than 0.001) and a raised serum concentration of luteinizing hormone (P = 0.06) in comparison with the non-smokers. The number of cigarettes consumed was apparently immaterial. The concentrations of oestrone, oestradiol and follicle-stimulating hormone were similar in the two groups. This study lends support to the hypothesis that the observed decreased risk of endometrial and breast cancer associated with cigarette smoking may be mediated by androgenic protection.

Androstenedione↗
PubMed1990

Direct measurement of abdominal fat by dual photon absorptiometry.

We have assessed photon absorptiometry as a new technique for direct measurement of the abdominal fat percentage (AF%). The accuracy of the method was assessed in vitro with phantoms consisting of ox muscle, lard, and a mixture of both. The results showed good linearity (r = 0.999). The in vitro reproducibility and the in vivo reproducibility were s.d. = 2.0 and s.d. = 2.8 (AF%), respectively. The AF% was measured in 148 healthy post-menopausal women and found to correlate with other measurements of fatness, such as total body fat per cent (r = 0.82, P less than 0.001), body mass index (r = 0.79, P less than 0.001) and the ratio of waist-to-hip circumference (r = 0.59, P less than 0.001). The waist-to-hip ratio, an important predictor of cardiovascular disease, was more tightly correlated with AF% than with body mass index. We conclude that this method may be a useful new research tool for direct measurements of abdominal fat, a possible cardiovascular risk factor.

Abdomen↗