Biomedical subjects

G Berg

Publications and source records attributed to G Berg.

At least 19 recordsLinked to original sources

PubMed2006

Cytokine secretion in decidual mononuclear cells from term human pregnancy with or without labour: ELISPOT detection of IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha.

Cytokines are believed to be important in maintaining pregnancy and in the process of labour induction in humans. The aim of this study was to investigate the secretion of the cytokines interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-10, transforming growth factor-beta (TGF-beta) and tumour necrosis factor-alpha (TNF-alpha) in decidual tissue with or without labour. Decidual tissue was collected from 32 healthy women undergoing elective caesarean sections before the onset of labour (n=17) or after normal vaginal delivery (n=15). Mononuclear cells were analysed for cytokine secretion with ELISPOT. To validate the widely used method of tissue collected at caesarean sections and after vaginal deliveries as a representative of before and after labour, respectively, placenta biopsies were collected from 12 healthy women to study the expression of the prostaglandin pathway enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E(2) synthase (mPGES). Decidual mononuclear cells from term human pregnancy spontaneously secrete IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha. No difference was seen in cytokine secretion with or without labour, indicating that decidual leukocytes are not the main cell population responsible for plausible cytokine regulation in the process of termination of pregnancy. Placental tissues obtained after vaginal delivery showed a higher mRNA expression of the prostaglandin regulating molecules COX-2 and mPGES than tissues from caesarean sections before the onset of labour, validating that the model can be used as a representative of the state before and after labour.

Adult↗

PubMed2006

Effect of lifelong iodine supplementation on thyroid 131-I uptake: a decrease in uptake in euthyroid but not hyperthyroid individuals compared to observations 50 years ago.

BACKGROUND: In Sweden, iodine has been added to table salt (10 mg/kg) since 1936; this amount was increased in 1966 to 50 mg/kg. OBJECTIVE: To investigate a euthyroid Swedish population (n = 44, 60-65 years) with its entire lifespan with iodine supplementation as for 24-h 131-I uptake (24 h IU) and thyroid nodularity (thyroid scintigraphy). To compare the euthyroid 24 h IU with uptake of thyrotoxic individuals, and with observations from 1955. METHODS: The 24 h IU was used in euthyroid individuals after oral administration of 0.1 MBq/2.7 microCi radioiodine and imaging of the thyroid gland was carried out using 99mTc-pertechnetate. RESULTS: In 1999-2000, the mean 24 h IU in the euthyroid individuals was 21% (range 11-33%) and the normal (central 95%) reference interval was 14-30%. Scintigraphy suggested multinodular goitre in three euthyroid individuals. In Graves' patients (n = 53, 50-65 years), the mean 24 h IU was 61% (range 29-89%). In 1955, the 24 h IU in euthyroid individuals was higher (38%, range 10-70%), while hyperthyroid patients had uptake values similar to those recorded in the present investigation (mean 62%, range 40-90%). CONCLUSIONS: The population sample studied had to be small for ethical reasons. We conclude that the reference interval for 24 h IU is 14-30% in this population that had spent its entire lifespan with iodine supplementation. This is lower than that recorded in a Swedish euthyroid population half a century ago having had low-grade table-salt iodine supplementation for 20 years. Values for hyperthyroid patients, however, do not appear to have been affected likewise.

Aged↗

PubMed2006

[Aspects of sample size determination and power calculation illustrated on examples from rehabilitation research].

Often it is reported in medical studies that an expected effect could not be detected. This may be the case if the sample size had been too small to detect an effect which actually exists. This often is due to the fact that sound sample size estimation had been omitted prior to the study outset. As a result, it is not known how many persons should have been involved in the study to detect this effect if present. On the other hand, if sample size estimation has not been realized, more persons than needed might be included in the study. This is problematic for economic and in particular for ethical reasons. The aim of this paper is to point out the principles of sample size estimation as well as to emphasize its importance not only in general but also in medical rehabilitation research.

Clinical Trials as Topic↗

PubMed2006

Intrapartum transfer from a birth centre to a hospital - reasons, procedures, and consequences.

BACKGROUND: Investigation of the reasons for the transfer of women from a birth centre to a hospital in the course of childbirth as well as modalities and effects. PATIENTS AND METHOD: In the prospective investigation from September 1, 1999 to August 31, 2001, information was collected for all women in Berlin and Bavaria transferred intrapartum from a birth centre to a hospital concerning the reason for the transfer, stage of delivery at the start of transfer, details of the transport, accompaniment, state of mother and medical diagnosis on arrival at the hospital, further progress of delivery, and the condition of the baby postnatum. Comparison groups were formed by all birth centre deliveries in Berlin and Bavaria 1999/2000 (n = 3060) and hospital deliveries in Berlin and Bavaria 1998/1999 (selected data, n = 89 696 births). RESULTS: Three hundred and sixty transfer cases could be evaluated, and a majority of these were nulliparous. The most frequent reasons for transfer were prior premature rupture of membranes and failure to progress in labor. Fifty-seven percentages of the women who were transferred subsequently delivered spontaneously, with an episiotomy rate of approximately 30%. 1-min Apgar value < or = 7 were frequently in nulliparous and multiparous patients in the transfer group than in the comparison groups, as were 5-min Apgar values < or = 7 and pH < 7.10 in arterial cord blood in particular for nulliparous in the transfer group. Hospitalisation of neonates born to the transfer group and in particular the nulliparous was significantly more common. CONCLUSIONS: Women delivering in a birth centre represent in general a low-risk group as a result of careful preselection by the centres. However, some neonatal data and the high rate of operative deliveries (cesarean section, forceps, and vaginal extraction) indicate that the intrapartum-transferred women, in particular when nulliparous, represent than a special high-risk group.

Adult↗

PubMed2006

Determination of intrathyroidal iodine by X-ray fluorescence analysis in 60- to 65-year olds living in an iodine-sufficient area.

OBJECTIVES: X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations of iodine deficiency or iodine overload, the method has not so far been widely used. The objective was to investigate the applicability of the XRF method in a larger number of subjects. DESIGN AND SUBJECTS: The study comprised 37 individuals, aged 60-65 years, who had spent their entire life with iodine supplementation through iodinated table salt. Individuals with (previous) thyroid disease were excluded. The individual thyroid function had previously been evaluated by measurements of thyroid-related hormones, thyroid volume and 131-Iodine (131I) uptake which indicated a sufficient iodine intake of the population in the area. Iodine in the right thyroid lobe in each subject was examined using XRF. RESULTS: The mean thyroid iodine concentration was 0.4 mg mL(-1), corresponding to a mean total iodine content of 5.2 mg (range 0.9-20.2). There was a pronounced difference between individuals. No correlation was found between iodine concentration and 131I uptake or thyroid volume. Neither was iodine content and 131I uptake correlated. CONCLUSIONS: In a population living under iodine-sufficient conditions, a large variation of iodine stored in the thyroid is compatible with euthyroidism. Determination of the iodine pool by XRF investigation is feasible in a clinical setting and the method offers a unique possibility to study the intrathyroidal iodine pool in subjects with thyroid disease. The low radiation dose enables the use of the method in pregnant women and also in young individuals.

Aged↗

PubMed2006

Validation of short term recall of mobile phone use for the Interphone study.

AIM: To validate short term recall of mobile phone use within Interphone, an international collaborative case control study of tumours of the brain, acoustic nerve, and salivary glands related to mobile telephone use. METHODS: Mobile phone use of 672 volunteers in 11 countries was recorded by operators or through the use of software modified phones, and compared to use recalled six months later using the Interphone study questionnaire. Agreement between recalled and actual phone use was analysed using both categorical and continuous measures of number and duration of phone calls. RESULTS: Correlations between recalled and actual phone use were moderate to high (ranging from 0.5 to 0.8 across countries) and of the same order for number and duration of calls. The kappa statistic demonstrated fair to moderate agreement for both number and duration of calls (weighted kappa ranging from 0.20 to 0.60 across countries). On average, subjects underestimated the number of calls per month (geometric mean ratio of recalled to actual = 0.92, 95% CI 0.85 to 0.99), whereas duration of calls was overestimated (geometric mean ratio = 1.42, 95% CI 1.29 to 1.56). The ratio of recalled to actual use increased with level of use, showing underestimation in light users and overestimation in heavy users. There was substantial heterogeneity in this ratio between countries. Inter-individual variation was also large, and increased with level of use. CONCLUSIONS: Volunteer subjects recalled their recent phone use with moderate systematic error and substantial random error. This large random error can be expected to reduce the power of the Interphone study to detect an increase in risk of brain, acoustic nerve, and parotid gland tumours with increasing mobile phone use, if one exists.

Case-Control Studies↗

PubMed2004

A new approach to the quantitative measurement of dense LDL subfractions.

OBJECTIVES: Small dense low-density lipoproteins (LDLs) should be considered a major risk factor for cardiovascular disease, but there is still no recommended method for measuring them or expressing clinical values. We measured the dense LDL portion relatively simply by isolating it using density ultracentrifugation and then giving it a relative, quantitative value. DESIGN AND METHODS: Dense LDLs (d=1.048-1.063 g/mL) were isolated from human plasma at the same time as total LDL (d=1.021-1.063 g/mL) by means of sequential ultracentrifugation, and the former was assessed as a percentage of the latter. A receiver operator characteristic (ROC) curve was used to compare the different LDL components as markers of dense LDLs. The proposed method was compared with non-denaturing gradient gel electrophoresis (NDGGE). In order to obtain clinical data, the dense LDL portion was measured in diabetic and postmenopausal subjects and healthy controls. RESULTS: The ROC curve showed that cholesterol level was a more accurate marker of dense LDLs. The within-run precision (CV) was 2.28%, and the between-run CV was 5.1%. Analytical recovery was 80.2+/-1.6%. The correlation between the proposed method and NDGGE was r=0.90, p<0.001. The dense LDL percentage significantly correlated with serum triglyceride (r=0.57, p<0.001) and high-density lipoprotein cholesterol levels (r=-0.33, p<0.01), but not with the LDL-cholesterol/apolipoprotein B ratio. The diabetic patients and postmenopausal women had higher dense LDL values than the healthy controls. CONCLUSIONS: The results obtained using this procedure are in line with those obtained using NDGGE, which is the conventional assay system for measuring LDL size. Determining the small dense LDL portion by means of its cholesterol content may be a better approach to characterising the risk of cardiovascular disease, even in the presence of relatively normal LDL-cholesterol levels.

Adult↗

PubMed2004

Lipid and lipoprotein profile in menopausal transition. Effects of hormones, age and fat distribution.

The behavior of lipoproteins during the menopausal transition and their relationship with sex hormones and body fat distribution is still unclear. Our aim was to evaluate atherogenic IDL, LDL, Lp(a) and antiatherogenic HDL lipoproteins in four groups of women: premenopausal (n = 20), menopausal transition women with menstrual bleeding (n = 31), menopausal transition women with 3 to 6 months amenorrhea (n = 36), and postmenopausal women (n = 30). We also measured their FSH, LH and estradiol levels along with BMI and waist circumference. Menopausal transition and postmenopausal women showed higher values of waist circumference (p < 0.0032), LDL-cholesterol (p < 0.002), IDL-cholesterol (p < 0.002) and apoprotein B (p < 0.0001) than premenopausal women. Total-cholesterol (p < 0.0001), triglycerides (p < 0.004), IDL-cholesterol and Lp(a) were higher in menopausal transition women with amenorrhea and in postmenopausal women in comparison with premenopausal women. After adjustment according to age and waist circumference, multiple regression analysis showed the increase in total-cholesterol and LDL-cholesterol to be linearly associated to menopausal status and estradiol concentration, whereas Lp(a) was only related to menopausal status. Age was found to be an independent variable in relation to apoprotein B concentration changes. The effect of menopausal status on TG levels did not remain in the model when age, waist and BMI were included (beta = 0.05, p = 0.356). HDL-cholesterol levels were the same in all the groups. Menopause, age and the increase in abdominal fat distribution were three independent and significant factors impairing lipoprotein profiles from the beginning of the menopausal transition.

Adipose Tissue↗

PubMed2004

Urinary iodine and thyroid volume in a Swedish population.

OBJECTIVE: To evaluate the present efficacy of an iodine supplementation programme working in Sweden since 1936 by studying the iodine excretion in urine and determining the thyroid volume in a population in a semi-rural community. DESIGN: A cross-sectional population screening comprising three age groups with randomly selected individuals: group 1 (children): 7-9 years, n = 61 (invited 70); group 2 (teenagers): 15-17 years, n = 61 (invited 63), and group 3 (adults): 60-65 years; n = 57 (invited 73). MAIN MEASUREMENTS: Urinary iodine was measured spectrophotometrically; thyroid volume by ultrasonography. RESULTS: The median values for urinary iodine concentration in the three age groups were 194 microg L(-1), 246 microg L(-1) and 190 microg L(-1), respectively, indicating an adequate iodine intake. In the 7-9 year olds, the median value of the thyroid volume was 4.7 mL, which coincides with the recently established upper limit of normal children of that age, 4.0-4.8 mL (ICCIDD, International Council for control iodine deficiency disorders). One eight-year-old boy had a pronounced goiter. Four teenagers and one adult were found to have an enlarged thyroid gland according to earlier established reference volumes (15 years >16 mL; adults > 25 mL). CONCLUSION: We conclude that the iodine intake in our region is sufficient in age groups ranging from young children to pre-retirement adults.

Adolescent↗

PubMed2004

Comparison of survival following coronary artery bypass grafting vs. percutaneous coronary intervention in diabetic and non-diabetic patients: retrospective cohort study of 6320 procedures.

AIM: To determine whether mortality following percutaneous coronary intervention vs. coronary bypass grafting varies according to whether or not patients have diabetes. METHODS: We used the Scottish Coronary Revascularization Register to identify all patients undergoing revascularization in Scottish NHS hospitals since 1997. We excluded single-vessel disease, left main stem stenosis, and bypass grafting performed at the same time as other operations. We used death certificate data from the Registrar General to identify all subsequent deaths. RESULTS: Of the 6320 eligible procedures, 5042 (80%) were bypass grafts and 1278 (20%) angioplasties. Overall 831 (13%) patients had diabetes with no significant difference by procedure (13% vs. 12%). A total of 382 deaths occurred over a mean follow-up of 2.3 years. Diabetic patients had a poorer prognosis following both surgery (adjusted hazards ratio (HR) 1.43, 95% confidence interval (CI) 1.08, 1.89) and percutaneous intervention (adjusted HR 2.58, 95% CI 1.43, 4.63). Among non-diabetic patients, no significant differences in mortality were detected between the two procedures. Among diabetic patients, no significant difference was detected in those with two-vessel disease. In those with impaired left ventricular function and triple-vessel disease, angioplasty was associated with a significantly higher risk of death (adjusted HR 3.58, 95% CI 1.40, 9.19). CONCLUSIONS: This is the first study to demonstrate statistically significant results that support the BARI trial findings. Our study demonstrated a significant difference for triple-vessel disease but not two-vessel disease. The former may be due to incomplete revascularization using percutaneous intervention. Our results require corroboration from randomized trials.

Aged↗

PubMed2003

Evidence for dose-dependent effects on plant growth by Stenotrophomonas strains from different origins.

AIMS: To assess the influence of Stenotrophomonas on plants, the interaction of 16 Stenotrophomonas strains from clinical and environmental sources with strawberry plant seedlings was analysed. METHODS AND RESULTS: In vitro, all Stenotrophomonas strains influenced plant growth when applied to seedlings. Whereas most of the Stenotrophomonas strains promoted root growth and hair development, a statistically significantly negative influence on the length of stem was found. Although strains from a clinical origin also showed statistically significant effects on plants, this was generally lower when compared with environmental strains. For three selected strains, a strong dose-dependent effect was observed for all parameters. In vitro, a correlation was found between plant growth promotion and production of a plant growth hormone, indole-3-acetic acid (IAA). Xanthomonas campestris, a phylogenetically very closely related species to Stenotrophomonas, was used as a phytopathogenic control. It too confirmed the reduction of plant growth in this in vitro system. CONCLUSIONS: Independent of their origin, Stenotrophomonas strains can produce IAA in vitro and subsequently, influence plant growth. The effect of Stenotrophomonas presence on plants was dose-dependent. SIGNIFICANCE AND IMPACT OF THE STUDY: The dose-dependent effect of Stenotrophomonas, a bacterium of both biotechnological and medical interest, is of great interest for biocontrol applications of plant-associated strains. This paper is the first report that clearly demonstrates the phytopathogenic capacity of Stenotrophomonas.

Fruit↗

PubMed2003

Cytokine secretion patterns of NK cells and macrophages in early human pregnancy decidua and blood: implications for suppressor macrophages in decidua.

PROBLEM: Local immune modulation has been shown to be of considerable importance for the maintenance of successful pregnancy. We have previously reported the secretion of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cellular source of cytokine secretion in the decidua, and compare this to secretion patterns in peripheral blood. METHOD OF STUDY: Decidual tissue and peripheral blood was collected from 20 women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were enriched by immunomagnetic cell separation and cytokine secretion was detected by enzyme-linked immunosorbent spot-forming cell assay. RESULTS: Decidual and peripheral monocytes/macrophages and NK cells spontaneously secrete IFN-gamma, IL-4 and IL-10. The number of IL-10 secreting cells was significantly higher in decidual macrophages compared with decidual non-monocytic cells as well as compared with blood monocytes/macrophages. These differences were not seen for IFN-gamma or IL-4. CONCLUSIONS: Our results indicate that decidual macrophages subserve important suppressive functions in the pregnant uterus.

Adolescent↗

PubMed2002

Radioiodine ablation and therapy in differentiated thyroid cancer under stimulation with recombinant human thyroid-stimulating hormone.

We investigated whether recombinant human TSH (rhTSH) safely and effectively induces uptake of high-dose 131-iodine (131I) to ablate thyroid remnant or treat disease, in patients with well-differentiated thyroid carcinoma. Eleven consecutive patients unable to tolerate thyroid hormone withdrawal received one im injection of 0.9 mg rhTSH on 2 consecutive days before receiving 4000 MBq (approximately 108 mCi) radioiodine orally. Eight patients received one, and 3 patients 2 courses. Our series comprised 7 women and 4 men (mean age, 78 yr, range: 56-87 yr). Ten patients had undergone total or near-total thyroidectomy up to 19 yr earlier. rhTSH-stimulated single course radioiodine with the intention to ablate thyroid remnant was performed in 3 patients, with following estimation of radioiodine uptake and TG measurements. Of another 8 patients given this treatment palliatively, 5 had radiological, clinical and/or laboratory response, including: 80% decreased pathological uptake between treatment courses; pronounced decrease in bone pain; diminished symptoms; improved physical condition and quality of life; lower serum TG concentration; and/or normalization of TG recovery test. Two patients with small lung metastases on computed tomography had no detectable radioiodine uptake or other response; they also lacked uptake after withdrawal-stimulated radioiodine treatment. Despite being elderly and frail, patients generally tolerated treatment well; rhTSH caused nausea in one patient and transiently increased pain in bone and soft tissue lesions in another. We conclude that rhTSH-stimulated high-dose radioiodine for remnant ablation or tumor treatment is safe, feasible and seemingly effective, enhancing quality of life and offering reasonable palliation in patients with advanced disease.

Aged↗

PubMed2002

Vasorelaxant properties of isolated human radial arteries: comparison with internal mammary arteries.

Radial arteries, used in revascularisation surgery, are prone to spasm. We have examined the ability of nitrovasodilators, calcium channel blockers, and K(ATP) channel openers to cause vasodilation, and to attenuate contractions due to depolarisation and receptor activation in radial and mammary arteries used in coronary artery bypass graft surgery. Two to three millimetre rings of artery obtained from patients at surgery were studied in organ baths in vitro. Constriction to KC1 and phenylephrine was examined before and again after treatment of the rings with drug or vehicle. Calcium channel blockers were the only compounds to inhibit contractions to both KC1 and phenylephrine. Sodium nitroprusside attenuated constriction to phenylephrine but not KC1 in both vessels. K(ATP) channel openers similarly attenuated constriction to phenylephrine in radial arteries but were much less effective in mammary arteries. These studies support the continued use of calcium blockers after revascularisation with radial artery but suggest that other classes of drug may be as effective at minimising spasm due to receptor mediated constriction.

Adult↗

PubMed2002

Spontaneous secretion of interleukin-4, interleukin-10 and interferon-gamma by first trimester decidual mononuclear cells.

PROBLEM: A T-helper cell type 2 (Th2) cytokine dominated microenvironment has been predicted to be crucial for successful pregnancy. However, little information is available about local cytokine secretion in the human decidua. We determined the spontaneous secretion of interleukin-4 (IL-4), interferon-gamma (IFN-gamma) and IL-10 by decidual mononuclear cells at the single cell level and compared it with their secretion by peripheral blood mononuclear cells (PBMC) in the first trimester of pregnancy. METHODS OF STUDY: The cytokine secretion from decidual and blood cells was detected by a sensitive enzyme-linked immunosorbent spot-forming cell (ELISPOT)-assay. RESULTS: Cells secreting IL-4 (median 153, range 8-530), IL-10 (median 188, range 32-1600) and IFN-gamma (median 123, range 15-1140) were detected in all decidual and blood samples. The cytokine secretion showed a co-linear pattern in both the blood and decidua, i.e. when one cytokine was secreted at high levels, the others followed the trend. No correlation was found between the number of cytokine secreting cells in blood and decidua for any of the cytokines. CONCLUSIONS: Interleukin-4 and IL-10 are locally secreted in the decidua early during normal pregnancy, probably counteracting the fetal rejecting effects of co-expressed IFN-gamma. The cytokine secretion by blood cells does not generally reflect the local secretion pattern during first trimester pregnancy.

Adolescent↗

PubMed2002

Impact on lipoprotein profile after long-term testosterone replacement in hypogonadal men.

Testosterone serum levels may influence the lipoprotein metabolism and possibly atherogenic risk. Our aim was to investigate the effects of long-term testosterone supplementation in hypogonadal men on multiple lipoprotein markers. 18 Hypogonadal men were studied before and after 3, 6, and 18 (n = 7) months of treatment with testosterone enanthate. During treatment, serum testosterone and estradiol increased, reaching normal levels (p < 0.0001 and 0.003, respectively). This was associated with a decrease in HDL cholesterol (from 1.40 +/- 0.10 mmol/l to 1.22 +/- 0.08 mmol/l, p < 0.001) after six months at the expense of HDL2 cholesterol (p < 0.01), as well as apoprotein A1 (from 139 +/- 3.4 mg/dl to 126 +/- 3.0 mg/dl, p < 0.005). Hepatic lipase activity increased (p < 0.05) and correlated positively with testosterone (r = 0.56, p < 0.02) and negatively with HDL cholesterol (r = - 0.58, p < 0.02). Total and LDL cholesterol, triglycerides, and apoprotein B did not increase. Among the seven patients who completed 18 months of treatment, triglycerides, total cholesterol, LDL and HDL cholesterol, as well as total cholesterol/HDL cholesterol ratio values did not differ from baseline while apoprotein A1 (p < 0.03) and HDL cholesterol (p < 0.015) remained decreased and hepatic lipase unchanged. Restoration of testosterone levels in hypogonadal men in this study did not reveal unfavorable changes based on total cholesterol/HDL cholesterol and LDL cholesterol/apoprotein B ratios, which are both atherogenic risk markers. Whether the changes in light of lipoprotein metabolism will adversely influence cardiovascular risk over time remains to be determined.

Adult↗

PubMed2002

Kinetics of in vitro lipolysis of human very low-density lipoprotein by lipoprotein lipase.

BACKGROUND AND AIM: An initial step in the catabolism of triglyceride-rich lipoprotein involves the hydrolysis of the triglyceride moiety by lipoprotein lipase (LPL). As differences in the lipolytic behaviour of very low-density lipoprotein (VLDL) particles have been observed, it is possible that different VLDL particles have a different affinity to the enzyme, which means that their fate may partially depend on the LPL-mediated hydrolysis of their triglyceride content. Our aim was to determine whether variation in VLDL chemical composition affects their properties as a substrate for LPL. METHODS AND RESULTS: Isolated VLDL was incubated in vitro with bovine LPL to determine substrate affinity. Under optimal assay conditions, free fatty acids were measured and the kinetic indicators for in vitro triglyceride hydrolysis (Km and Vmax) were calculated. VLDL cholesterol (VLDL-C), VLDL-apoB and the cholesterol/triglyceride ratio were assessed and the triglyceride/protein and triglyceride/apoB ratios were calculated as lipoprotein size estimators. VLDL-C, VLDL-apoB and the VLDL-C/triglyceride ratio positively correlated with Km: r = 0.52, p < 0.01; r = 0.52, p < 0.03; r = 0.69, p < 0.001 respectively. No correlation was found between the VLDL-triglyceride/protein or the VLDL-triglyceride/apoB ratios and Km (r = -0.20, and -0.06 respectively, p = not significant). Of the subjects' anthropometric characteristics, only the waist/hip ratio significantly correlated with Km: r = 0.63, p < 0.01. CONCLUSIONS: In the present study, we investigated the substrate function of VLDL particles in vitro. Enzyme affinity seems to be associated with cholesterol-triglyceride content or the number of VLDL particles rather than particle size. It may be expected that VLDL with a low cholesterol/triglyceride ratio will be efficiently lypolised by LPL, thus leading to the formation of a smaller particle with atherogenic potential.

Animals↗

PubMed2001

Purification and properties of two chitinolytic enzymes of Serratia plymuthica HRO-C48.

The chitinolytic rhizobacterium Serratia plymuthica HRO-C48 was previously selected as a biocontrol agent of phytopathogenic fungi. One endochitinase (E.C. 3.2.1.14), CHIT60, and one N-acetyl-beta-1,4- D-hexosaminidase (E.C. 3.2.1.52), CHIT100, were purified and characterized. The endochitinase CHIT60, with an apparent molecular mass of 60.5 kDa, had a N-terminal amino acid sequence highly similar to that of chitinases A from Serratia liquefaciens and Serratia marcescens. The enzyme activity had its peak at 55 degrees C and pH 5.4, and increased by more than 20% in the presence of 10 mM Ca(2+), Co(2+) or Mn(2+). Activity was inhibited by 80% in the presence of 10 mM Cu(2+). CHIT100 appeared to be a monomeric enzyme with a molecular mass of 95.6 kDa and a pI of 6.8. Optimal activity was obtained at 43 degrees C and pH 6.6, and decreased by more than 90 % in the presence of 10 mM Co(2+) or Cu(2+). CHIT100 (100 microg ml(-1)) inhibited spore germination and germ tube elongation of the phytopathogenic fungus Botrytis cinerea by 28 % and 31.6 %, respectively. With CHIT60 (100 microg ml(-1)), the effect was more pronounced: 78 % inhibition of of germination and 63.9 % inhibition of germ tube elongation.

Amino Acid Sequence↗