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Biomedical subjects

A D Kester

Publications and source records attributed to A D Kester.

At least 55 records · Page 3Linked to original sources
PubMed1995

Long-chain polyene status of preterm infants with regard to the fatty acid composition of their diet: comparison between absolute and relative fatty acid levels in plasma and erythrocyte phospholipids.

The long-chain polyene (LCP) status of thirty-nine premature infants (birth weight < 1800 g) was evaluated. Twenty-seven infants were fed on an artificial formula, twelve received their own mother's breast milk. Fatty acid compositions of both plasma and erythrocyte (RBC) phospholipids (PL) were determined in umbilical venous blood and in weekly postnatal blood samples until the 28th day of life. Individual fatty acid levels were expressed as absolute quantities (mg fatty acid/l plasma or RBC suspension) and as relative (mg/100 mg total fatty acids) values. The changes with time in the absolute values for 22:6n-3 and 20:4n-6 in plasma were strikingly different from those of the relative values for these fatty acids. In plasma PL the inter-group differences in the absolute postnatal values for 22:6n-3 (P < 0.0005) and 20:4n-6 (P < 0.05) and the relative values for 22:6n-3 (P < 0.02) were significant, with lower fatty acid values in the formula-fed infants. In RBC PL, no significant inter-group differences in the postnatal 22:6n-3 and 20:4n-6 values were found. Based on the assumption that it is desirable for formula-fed infants to achieve postnatal plasma LCP values at least comparable with those found in infants fed on human milk, the findings of the present study indicate that both n-3 and n-6 LCP should be added to preterm infant formulas. Moreover, the additional importance of absolute fatty acid levels was demonstrated, although analytical procedures need to be standardized to enable effective comparison of results from different research groups.

Dietary Fats↗
PubMed1995

Maternal essential fatty acid patterns during normal pregnancy and their relationship to the neonatal essential fatty acid status.

Although essential fatty acids (EFA) and their longer chain, more unsaturated derivatives play a major role during pregnancy, hardly any information is available with respect to the course of the maternal EFA status during an uncomplicated pregnancy and its relationship to the neonatal EFA status. Therefore, a longitudinal study was started in which 110 pregnant women gave repeated blood samples from the 10th week of gestation until delivery. After birth a blood sample from the umbilical vein and a maternal venous blood sample were collected as well, and 6 months after delivery a final blood sample from the mother was taken. The absolute (mg/l) and relative (% total fatty acids) amounts of the fatty acids in plasma phospholipids were determined. The total amounts of fatty acids increased significantly during pregnancy. This pattern was similar for the individual fatty acids and fatty acid families. The relative amount of linoleic acid (18:2n-6) did not change during pregnancy, whereas the relative amount of arachidonic acid (20:4n-6) decreased. Despite maternal mobilization of docosahexaenoic acid (22:6n-3, DHA), suggested by a temporary increase in the DHA status until 18 weeks gestation, the DHA status steadily declined thereafter. This pattern was associated with a progressive increase in the DHA deficiency index in maternal blood throughout pregnancy and resulted in a sub-optimal neonatal DHA status. The overall maternal EFA status also declined steadily during pregnancy. Therefore, the question arises whether the mother, under the prevailing dietary conditions, is able to meet the high fetal requirement for EFA.

Adult↗
PubMed1995

Effect of variable protein intake on whole-body protein turnover in young men and women.

The effect of the amount of protein intake (12% and 21% of total energy intake, diet A and diet B, respectively) on nitrogen balance and whole-body protein turnover (PT) was measured in 19 young men and 10 young women (aged 30 +/- 5 and 27 +/- 4 y, respectively). In young adults, mean nitrogen balance was approximately zero during diet A whereas it was positive during diet B. In young adults, PT was significantly higher during diet B in comparison with diet A. This was also seen in elderly subjects, as described before. From a comparison of the current data with the data previously obtained in elderly subjects it can be concluded that during diet A young adults had PT rates higher than those of elderly subjects. During diet B, PT of young men was comparable with the PT of elderly men whereas young women still had higher PT rates than elderly women (even when corrections were made for differences in body composition).

Adult↗
PubMed1995

Does a reduction in general practitioners' use of diagnostic tests lead to more hospital referrals?

BACKGROUND: Individual feedback on general practitioners' requests for tests can improve the quality of their test ordering behaviour. Little is known of the side effects on hospital referral behaviour when the use of tests is reduced through feedback. AIM: A study was undertaken to explore changes in general practitioners' hospital referral rates in a region where their use of diagnostic tests is reduced through feedback. METHOD: Trends in test requests and of first referrals to specialists were compared among 64 general practitioners in the Maastricht region of the Netherlands where routine feedback on test ordering behaviour is provided by the diagnostic coordinating centre. RESULTS: Reduction in diagnostic test use was not accompanied by a higher hospital referral rate, not even for specialties related to tests discussed in feedback. Good responders to feedback had decreased hospital referral rates in contrast to increased rates for poor responders (P < 0.01). CONCLUSION: Reducing the volume of general practitioners' diagnostic tests through feedback does not lead to more specialist referrals. Together with lower test use, fewer hospital referrals were seen.

Diagnostic Tests, Routine↗
PubMed1994

Short-term variation in the elastic properties of a muscular artery in humans.

1. Information on the interaction between mechanical strain and the elastic properties of large arteries could give insight to the origin of haemodynamic vascular injury, possibly resulting in formation of atherosclerotic plaques. Intra-individual variation in the elastic properties of muscular arteries measured using non-invasive techniques has been observed. This variation could be due to changes in blood pressure, since the elastic properties of muscular arteries are strongly non-linear. 2. The objective of the present study was to evaluate variability in the elastic properties of a muscular artery over a time period of up to 1 h. Furthermore, the relation between changes in elastic properties and alterations in blood pressure was studied. With a non-invasive high-resolution ultrasound technique, the diameter and distension of the femoral artery were assessed by repeated measurements in 10 healthy subjects (mean age 27 +/- 2.9 years) under resting conditions over 40-60 min. Intra-arterial blood pressure of the contralateral common femoral artery and heart rate were recorded simultaneously. From the distension and pulse pressure, the distension/pressure ratio was calculated, a measure of the compliance. For each parameter the variation coefficient was computed. 3. In all subjects a considerable variation was found in distension (mean variation coefficient 14.8%) but not in pulse pressure (mean variation coefficient 3.7%). The expected positive correlation between pulse pressure and distension was absent in eight subjects. As a consequence, large intra-individual variation was found in the distension/pressure ratio (mean variation coefficient 15.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Cow's milk protein intolerance in infants under 1 year of age: a prospective epidemiological study.

Incidence and clinical manifestation of cow's milk protein intolerance (CMPI) were studied in 1158 unselected newborn infants followed prospectively from birth to 1 year of age. No food changes were required in 914 infants who were used as healthy controls. When CMPI was suspected (211 infants), diagnostic dietary interventions according to a standard protocol were performed. After exclusion of lactose intolerance, two positive cow's milk elimination/challenge tests were considered diagnostic of CMPI. Two hundred and eleven symptomatic infants were examined for possible CMPI. A large group of 80 infants improved on a lactose reduced formula. In 87/211 infants CMPI was excluded (sick controls). Finally CMPI was proven in 26 infants. The calculated incidence rate for CMPI was 2.8%. The principal symptoms in infants with CMPI were gastrointestinal, dermatological and respiratory in 50%, 31% and 19% respectively. A positive family history for atopy (first or second degree relatives) was more frequent in either CMPI infants (65%), or sick controls (63%) when compared to either healthy controls (35%) or infants improving on a low lactose formula (51%). Differences between patients with CMPI and sick controls were only found for the presence of atopy in at least 2 first degree relatives [(5/26 in CMPI infants and 4/87 in sick controls (P < 0.05)] and for multiorgan involvement [10/26 infants with CMPI as opposed to 12/87 in the sick control group (P < 0.02)]. These statistical differences are too weak to be of clinical value.

Humans↗
PubMed1993

The effect of replacement of dietary fat by palm oil on in vitro cytokine release.

In the present study the effect of replacement of dietary fat by palm oil in the normal Western diet on the in vitro release of the inflammatory cytokines tumour necrosis factor (TNF), interleukin (IL)-6 and IL-8 was examined. A maximal replacement of 700 g/kg dietary fat was achieved for thirty-eight male volunteers who consumed either a palm-oil diet or a control diet in a double-blind, cross-over study with 6-week experimental periods, and 3-week run-in and wash-out periods. At the end of both experimental periods, whole blood was stimulated in vitro with 0.02 (sub-optimal), or 10 ng lipopolysaccharide (LPS)/ml (maximal), whereafter TNF, IL-6, and IL-8 concentrations in the culture supernatant fraction were measured using specific enzyme-linked immunosorbent assays (ELISA). Mean cytokine production with sub-optimal, or maximal LPS stimulation of peripheral whole blood was similar for both the palm oil, and the control group. The relative TNF response, however, was reduced by replacement of dietary fat with palm oil. Separate analysis of the data from the first and second experimental periods strongly suggested that the residual effect of the palm-oil diet on the relative TNF response was longer than 9 weeks. Cytokine homeostasis determines the course of the inflammatory response and the progression of atherosclerosis. The effect of palm-oil consumption on the proneness of the peripheral blood cells to produce TNF may, therefore, alter the prevalence of these common diseases.

Adult↗
PubMed1993

Effect of the pattern of food intake on human energy metabolism.

The pattern of food intake can affect the regulation of body weight and lipogenesis. We studied the effect of meal frequency on human energy expenditure (EE) and its components. During 1 week ten male adults (age 25-61 years, body mass index 20.7-30.4 kg/m2) were fed to energy balance at two meals/d (gorging pattern) and during another week at seven meals/d (nibbling pattern). For the first 6 d of each week the food was provided at home, followed by a 36 h stay in a respiration chamber. O2 consumption and CO2 production (and hence EE) were calculated over 24 h. EE in free-living conditions was measured over the 2 weeks with doubly-labelled water (average daily metabolic rate, ADMR). The three major components of ADMR are basal metabolic rate (BMR), diet-induced thermogenesis (DIT) and EE for physical activity (ACT). There was no significant effect of meal frequency on 24 h EE or ADMR. Furthermore, BMR and ACT did not differ between the two patterns. DIT was significantly elevated in the gorging pattern, but this effect was neutralized by correction for the relevant time interval. With the method used for determination of DIT no significant effect of meal frequency on the contribution of DIT to ADMR could be demonstrated.

Adult↗
PubMed1993

Value of immunohistochemical laminin staining in transitional cell carcinoma of human bladder.

A prospective immunohistochemical study of 66 human bladder biopsies with and without transitional cell carcinoma (TCC) of the bladder was performed to assess the diagnostic and prognostic value of laminin staining in TCC of the human bladder. In all normal and nonmalignant inflammatory specimens, a continuous intact basement membrane (BM) laminin could be identified. In bladder cancer specimens laminin staining revealed focal interruption of the subepithelial BM with microinvasion in 2 of 6 specimens initially diagnosed as Tis(Pis) and 7 of 25 specimens initially diagnosed as pTa tumors. A statistically significant association between the pT category and BM interruption was found (p < 0.025). BM loss was directly proportional with the stage of the tumor. However, no significant association could be observed between BM interruption and the grade of the tumor (p > 0.25). In a short-term follow-up (mean 16 months) a statistically significant correlation (p = 0.01) could be observed between tumor recurrence and BM integrity in that a higher recurrence rate and shorter recurrence-free interval was found in patients with interrupted BM versus those with intact BM. Assessment of the vascular BM-staining pattern revealed interruption in specimens from 5 patients who died from advanced metastatic tumors. The metastatic process was found to be closely associated with focal interruption of the subendothelial BM (p < 0.001). From our results it appears that the adjunct use of immunohistochemical laminin staining in the histopathologic examination of TCC of the bladder is essential in more exact identification of the different pathologic stages and is also of help in the more detailed prediction of tumor behavior and prognosis.

Aged↗
PubMed1992

Effect of feedback on test ordering behaviour of general practitioners.

OBJECTIVE: To assess the effect of feedback on the test ordering behaviour of general practitioners. DESIGN: Comparison of requests at two diagnostic centres, and internal comparison between tests which were discussed in feedback and tests which were not. SETTING: A diagnostic centre in Maastricht giving feedback and another elsewhere in the Netherlands (laboratory A) not giving feedback. SUBJECTS: All 85 general practitioners in the region of Maastricht, and all general practitioners in the region of laboratory A. MAIN OUTCOME MEASURES: Numbers of tests requested by general practitioners. RESULTS: Requests at the Maastricht diagnostic centre decreased soon after the onset of feedback whereas there was a persistent increase in requests at laboratory A. Tests that were discussed showed the strongest decrease (maximum 40%), though tests that were not discussed decreased as well (maximum 27%). CONCLUSIONS: Feedback on diagnostic requests may exert a strong influence on request behaviour. Four years after the onset of feedback the effects were still noticeable.

Clinical Laboratory Techniques↗
PubMed1992

Carpal tunnel syndrome: prevalence in the general population.

To study the prevalence of carpal tunnel syndrome (CTS) in the general population and the value of brachialgia paraesthetica nocturna (BPN) in diagnosing CTS, an age and sex stratified random sample of 715 subjects was taken from the population register of Maastricht (The Netherlands) and surrounding villages, between September 1983 and July 1985. The response rate was 70%. Of these, 12 CTS cases had already been diagnosed. Of the remaining subjects, 64 (13 men, 51 women) woke up because of BPN. Among these subjects 1 man and 23 women were found to have CTS. The prevalence rate of undetected CTS was 5.8% [95% confidence interval (CI): 3.5-8.1%] in adult women; 3.4 percent (95% CI: 1.5-5.3%) had already been diagnosed as CTS. The overall prevalence rate for men was 0.6% (95% CI 0.02-3.4%). These figures have to be regarded as minimal estimates. The overall diagnostic value of BPN for CTS was 38%, while for women only this was 45% (95% CI: 31-60%).

Adult↗
PubMed1992

Fat-free mass as a function of fat mass and habitual activity level.

The best predictor of energy expenditure in man is the fat-free mass of the body. Fat-free mass explains most of the variation in resting metabolic rate and even in total metabolic rate under sedentary conditions. We studied possible determinants of fat-free mass as routes to influence energy metabolism. Existing data sets were analysed with observations on height, fat mass (FM), fat-free mass (FFM), and habitual level of physical activity (PA). PA was calculated from average daily metabolic rate (ADMR) as measured over 1-4-week intervals with 2H2(18)O and basal metabolic rate (BMR): PA = ADMR/BMR. Ninety-six subjects, 66 females and 30 males, from 7 different studies were included. FFM and FM were adjusted for height by taking its ratio to the square of height, in analogy with the body mass index. Subsequently, all analyses were corrected for origin of the data. In a regression analysis FM explained 53 and 40% of the variation in FFM in females and males, respectively. Adding PA to the model raised the explained variation in FFM in females to 62%. In contrast with females (r = 0.10, n.s.), there was an independent relationship between PA and FM in males (r = -0.41, p less than or equal to 0.05), such that a higher PA was related to a lower FM. In conclusion, FFM is a function of FM and PA. The absence of an effect of exercise training on FFM, i.e. additional exercise in weight-reduction programmes, is discussed.

Adipose Tissue↗
PubMed1992

Replacement of dietary fat with palm oil: effect on human serum lipids, lipoproteins and apolipoproteins.

Thirty-eight male volunteers participated in a double-blind cross-over trial evaluating the effect of replacing the usual sources of saturated fat in the Dutch diet (animal fats and hydrogenated oils) by palm oil, which is virtually free of cholesterol and trans-fatty acids, on serum lipids, lipoproteins and apolipoproteins. Maximum (about 70%) replacement had no significant effect on serum total cholesterol or most lipoprotein fractions, but resulted in an 11% increase in serum high-density-lipoprotein (HDL)2-cholesterol relative to the control (P2 = 0.01). The palm-oil diet also caused an 8% decrease in low-density-lipoprotein (LDL):HDL2 + HDL3-cholesterol ratio (P2 = 0.02) as well as a 9% decrease in triacylglycerols in the low-density-lipoprotein fractions (P2 = 0.01). Palm oil consumption resulted in a 4% increase in serum apolipoprotein AI (P2 = 0.008) and a 4% decrease in apolipoprotein B (P2 = 0.01) relative to the control diet; the B:AI apolipoprotein ratio was decreased by 8% (P2 < 0.0001). These results were not significantly affected by the different lipoprotein E phenotypes of the volunteers. Although the observed differences were relatively modest, the present study, nonetheless, indicates that dietary palm oil, when replacing a major part of the normal fat content in a Dutch diet, may slightly reduce the lipoprotein- and apolipoprotein-associated cardiovascular risk profiles.

Adult↗
PubMed1992

The role of serum laminin P1 in the diagnosis of transitional cell carcinoma of the bladder.

In order to explore the possible role of serum laminin P1 in the diagnosis of transitional cell carcinoma (Tcc) of the bladder, the sera of 50 healthy control subjects and of 35 bladder-cancerous patients were measured by radioimmunoassay. In 27 patients (77%), the serum level was elevated above the upper limit of normal range. Statistically significant elevation could be determined in all stages and grades of Tcc of the bladder compared to those of normal subjects (mean +/- SD: 1.18 +/- 0.16 kU/l). Deterioration of the clinical stages or pathologic grades of the tumor was associated with a progressive increase in the mean values of serum laminin P1. A longer study with serial determination is planned to assess the prognostic significance of serum laminin in bladder cancer patients.

Aged↗
PubMed1991

Resting energy expenditure in patients with non-small cell lung cancer.

Resting energy expenditure (REE) was determined in 30 patients with newly detected non-small cell lung cancer. Measured values were compared with the values predicted by the Harris-Benedict (HB) formula. Mean REE was 20% higher than predicted. Sixty percent of the patients (18 patients) had an elevated REE (greater than or equal to 115%) compared with this formula. The prevalence of hypermetabolism in a group of patients with gastric and colorectal cancer was only 13% (13 of 104 patients). When corrected for fat-free mass (FFM), REE was still significantly higher (P less than 0.001) in the lung cancer group compared with the gastric and colorectal cancer group. Whereas weight loss in healthy men leads to an adaptational decrease in energy expenditure (EE), weight loss in the patients with lung cancer was accompanied by an increase in REE. Tumor stage, tumor localization, pulmonary function, or smoking behavior could not explain the observed increase in REE in patients with lung cancer. Therefore, these metabolic alterations appear to be tumor mediated.

Aged↗