Biomedical subjects

R A Erdman

Publications and source records attributed to R A Erdman.

At least 73 records · Page 4Linked to original sources

PubMed1996

Abomasal infusion of cis or trans fatty acid isomers and energy metabolism of lactating dairy cows.

Diets for dairy cows that provide or induce formation of trans isomers of polyunsaturated fatty acids result in reduced percentages of milk fat. The effect of abomasal infusion of trans-C18:1 fatty acid isomers on energy utilization by mature cows was determined. Six multiparous Holstein cows in midlactation had ad libitum access to a basal diet containing 50% forage and 50% concentrate. Treatments were 1) no infusion, 2) infusion of 630 g/d of a fat mixture high in cis-C18:1 isomers (64% cis-C18:1; 68% high oleic sunflower oil and 32% cocoa butter), and 3) infusion of 623 g/d of a fat mixture high in trans-C18:1 isomers (42% trans-C18:1; 90% partially hydrogenated soybean oil and 10% high linoleic safflower oil). The experiment was a replicated 3 x 3 Latin square design with 4-wk periods. Measurements of energy balance were made in open circuit respiration chambers during wk 4 of each period. Fat infusion increased milk production by 2.5 kg/d; apparent digestibility of DM, OM, energy, ADF, and ash by 1 to 4 percentage units; metabolizable energy by 11%; and NEL of the diet by 15%. Milk fat percentage and yield were higher when cows were infused with cis-C18:1 than when they were infused with trans-C18:1 (4.12% and 1.41 kg/d vs. 3.15% and 1.06 kg/d, respectively). Infusion of fat increased milk production, but trans-C18:1 reduced milk fat and energy output.

Abomasum↗

PubMed1995

[Quality of life following coronary surgery and balloon angioplasty; more chest pain and social inhibition following angioplasty].

OBJECTIVE: To determine the differences in quality of life between patients who had a coronary artery bypass graft (CABG) and patients who had a percutaneous transluminal coronary angioplasty (PTCA). DESIGN: Comparative and prospective study. SETTING: Rotterdam, the Netherlands. METHOD: 91 patients with multi-vessel coronary disease who had been randomised to CABG (n = 37) or PTCA (n = 54), as participants in the CABRI study (Coronary angioplasty or bypass revascularisation investigation) completed several psychological questionnaires. Besides, the severity of angina pectoris after the procedure was estimated using the Canadian Cardiovascular Society score. In a subpopulation of 36 patients (CABG:14; PTCA:22) the quality of life just before the intervention was measured, also using psychological questionnaires. RESULTS: A significant difference in angina pectoris was found between the two groups. The PTCA group experienced more chest pain (p < 0.01), at an average of 2.6 years after the intervention. The quality of life aspects did not differ between the two groups, except for 'social inhibition' (p < 0.05): the PTCA group experienced more problems and had less energy (p < 0.01). No significant differences between the PTCA and CABG groups were found regarding to the change in quality of life caused by the intervention. CONCLUSION: The persistent angina pectoris and social inhibition among patients who have had a PTCA need further study.

Angioplasty, Balloon, Coronary↗

PubMed1995

Regions outside of the CAAX motif influence the specificity of prenylation of G protein gamma subunits.

A family of GTP-binding regulatory proteins (G proteins) transduces signals across the plasma membrane from a large number of receptors to a smaller number of effectors. Recent studies indicate that a series of post-translational modifications are required for their association with the plasma membrane and for their function. In the case of the G protein gamma subunits, the post-translational modifications include the prenylation of a cysteine residue within a carboxyl-terminal CAAX motif. Although prenylation has been shown to involve the addition of either a C15 farnesyl or a C20 geranylgeranyl group to proteins, the structural requirements and functional consequences of adding different types of prenyl groups to various members of the gamma subunit family have not been examined. In the present study, we have employed the baculovirus expression system to study the structural requirements for attaching different types of prenyl groups to various members of the gamma subunit family. We show that the gamma 2 subunit is modified by a C20 geranylgeranyl group, consistent with the presence of a geranylgeranylation target sequence in this protein. However, we found that the gamma 1 and mutant gamma 2(Ser-71) subunits are modified by both C15 farnesyl and C20 geranylgeranyl groups, despite the presence of an accepted farnesylation target sequence in both of these proteins. Using chimeras of the gamma 1 and gamma 2 subunits, we provide evidence indicating that structural elements upstream of the carboxyl-terminal CAAX motif play a role in the recognition of members of the gamma subunit family by the appropriate insect and mammalian prenyltransferases.

Alkyl and Aryl Transferases↗

PubMed1995

Measuring quality of life in patients with myocardial infarction or stroke: a feasibility study of four questionnaires in The Netherlands.

OBJECTIVE: To test in patients with a history of myocardial infarction or stroke the feasibility of four quality of life measurements--the Nottingham health profile (NHP), the heart patients psychological questionnaire (HPPQ), the sickness impact profile (SIP), and the hospital anxiety and depression scale (HAD). DESIGN: Subjects were tested and retested after an interval of 14 days: questionnaires were self assessed. SUBJECTS: Participants were randomly selected from the Rotterdam stroke data bank (stroke patients; n = 16, mean (SD) age 66.0 (11.0) years and from the population based Rotterdam study (myocardial infarction; n = 20, mean (SD) age 72.7 (7.9) years, controls; n = 17, mean (SD) age 72.8 (7.3) years. MEASUREMENTS AND MAIN RESULTS: Mean (SD) administration times for the NHP, HPPQ, SIP, and HAD were 7.9 (3.5), 10.5 (4.3), 21.0 (9.8), and 5.5 (2.8) minutes respectively. On average, the test-retest reliability was good, with Spearman correlations ranging from 0.31 to 0.95. In spite of the limited size of the study, all instruments were able to show differences between the study groups. For instance, median SIP total scores for myocardial infarction and stroke patients were 12.4 (interquartile range 7.0-19.1) and 11.4 (5.9-15.4) respectively, compared with 7.7 (3.7-11.3) in the control group (p values of 0.04 and 0.14 respectively). CONCLUSIONS: This study suggests that use of the four instruments tested may be feasible and reliable for assessing aspects of quality of life in patients with a history of a myocardial infarction or stroke.

Aged↗

PubMed1995

Psychological and knowledge factors related to delay of help-seeking by patients with acute myocardial infarction.

Survival of an acute myocardial infarction (AMI) and subsequent prognosis are highly dependent on the time between onset of symptoms and medical intervention. The purpose of this study is to investigate which psychological and cardiovascular knowledge factors may contribute to the time the AMI patient takes to decide to seek medical help (patient delay). Three hundred patients took part in the study. They were interviewed and filled out several psychological questionnaires. The results show that patients who ask for medical help within half an hour have more cardiovascular knowledge, seek less distraction and more social support during the acute phase, compared to patients waiting longer. In general those who call soon appear to have easing thoughts in case of personal difficulties. They also deny their feelings of resentment to a lesser degree and interpret the symptoms of an AMI more often as originating in the heart. Future education campaigns should therefore not only address cardiovascular knowledge, but also coping and defense mechanisms.

Adaptation, Psychological↗

PubMed1995

Psychological aspects of non-cardiac chest pain.

Approximately 30% of patients visiting a cardiologist for the first time with complaints of chest pain appear to have normal coronary arteries. These patients generally have a higher prevalence of atypical chest pain, are relatively young, often female, in most cases suffer from panic disorder and have high scores on depression and anxiety scales. In this article some of the recent studies conducted in this particular line of research are reviewed and some possible explanations for the relationship between complaints and non-cardiac findings are presented. Furthermore, the ability of predicting non-cardiac chest pain from psychological factors and a range of follow-up studies are discussed. Finally the possibilities of treating cardiac phobia are mentioned.

Adult↗

PubMed1995

Prediction of body composition of dairy cows at three physiological stages from deuterium oxide and urea dilution.

To develop equations for predicting body composition, mature Holstein cows (n = 21) were slaughtered at three physiological stages (-7, 63, and 269 d postpartum) after consecutive intravenous dosing with urea and D2O. Blood was sampled at 0 and 12 min after dosing with urea for determination of urea space and from 0 to 72 h after dosing with D2O. Empty body water and total body water were estimated by dilution kinetics for D2O using two- and one-compartment models, respectively. At slaughter, body components were ground, sampled, and freeze-dried for chemical analysis. Prediction of empty body water by urea space was not an improvement over the prediction by body weight alone. Prediction by D2O dilution explained 73 and 87% of the variation in empty and total body water, respectively. Estimated body protein, as determined from empty body water, predicted actual body protein with an error of 4.7 kg. Daily DMI explained 84% of the variation in the DM of the gastrointestinal tract contents (DM fill). Estimations of empty body fat (R2 = .85) and empty body energy (R2 = .89) from D2O dilution were capable of detecting significant differences in body fat (42.9 kg) and body energy (375 Mcal) across physiological stages and might be useful for prediction of body composition changes during the lactation cycle.

Animals↗

PubMed1995

Fixed yield responses to increased milking frequency.

Data from 19 literature reports that measured the effect of milking frequency on milk yield were summarized. When milking three times daily was compared with milking twice daily, the three times daily yield was 3.5 kg/d higher with a 95% confidence interval of 3.1 to 3.9 kg/d. Response of fat yield to increased milking frequency, from twice daily to three times daily, was 92 g/d, and the 95% confidence interval was 67 to 117 g/d. Linear regression analysis showed that no relationship existed between twice daily milk yield or fat yield and the amount of increase of milk yield or fat yield caused by increasing milking frequency to three times daily. This result implied that increased milking frequency from twice to three times daily resulted in a fixed increase of 3.5 kg/d of milk yield and 92 g/d of fat yield, regardless of the yield for cows milked twice daily. Responses of primiparous and multiparous cows were similar in magnitude for twice daily versus three times daily milking frequency, suggesting that the separate adjustment factors currently used for conversion of three times to twice daily equivalents for primiparous and multiparous cows may not be needed if adjustments are expressed on the basis of actual yield. The numbers of comparisons of once daily and four times daily milking frequency with twice daily milking were limited, but showed no relationship with milk yield, and the mean response was -6.2 and 4.9 kg/d, respectively. These data also support the concept of a fixed yield response to altered milking frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Effects of prepubertal growth rate and diet on lipid metabolism in lactating Holstein cows.

The objectives were to determine the effects of rate of BW gain and type of silage fed before puberty on the partitioning of excess dietary energy between synthesis of milk and BW gain in second or third lactation. Accordingly, 41 Holstein heifers weighing 175 kg were fed diets containing either alfalfa silage or corn silage to gain either 725 or 950 g/d until BW was 325 kg and two estrous cycles were observed. Puberty occurred near 281 kg of BW. During second (n = 36) or third (n = 5) lactation, the cows were fed a control diet (60% forage and 40% concentrate) and a high energy diet (20% forage and 80% concentrate) in a double-reversal experimental design with three 6-wk periods. The rate of BW gain before puberty did not affect the magnitude of changes in DMI, milk yield, milk composition, or concentrations of thyroid hormones, insulin, bST, glucose, or lipids in serum when cows were switched from a control to a high energy diet during second or third lactation. However, compared with cows fed a corn silage diet, cows fed alfalfa silage between 175 and 325 kg of BW had more depressed yields of fat, total solids, and FCM when fed the high energy diet than when fed the control diet during second or third lactation. Increased deposition of fat in adipose and mammary tissues of cows with mean BW gain in excess of 950 g/d or fed a corn silage diet between 175 and 325 kg of BW did not result in more pronounced depression of milk fat percentage when cows were switched from a control to a high energy diet during second or third lactation. Overall, neither rate of BW gain nor type of silage fed between 175 and 325 kg of BW had a major influence on partitioning of excess dietary energy between synthesis of milk and BW gain during second or third lactation.

Adipose Tissue↗

PubMed1995

Milk fat depression, the glucogenic theory, and trans-C18:1 fatty acids.

Metabolic and endocrinological characteristics were compared for cows that differed in the extent of milk fat depression. Forty-one multiparous Holstein cows were fed control (40% concentrate and 60% forage) and high concentrate (80% concentrate and 20% forage) diets in a doubale-reversal design. Cows showing one or more percentage units of depression in milk fat were arbitrarily classified as responders (n = 26); those remaining were classified as nonresponders (n = 15). Compared with nonresponders, responders had greater increases in DMI, estimated NEL intake and balance, BW, milk yield, protein and lactose yields in milk, weight percentage of trans-C18:1 fatty acids in milk, and concentrations of triiodothyronine and thyroxine in serum when switched from the control diet to the 80% concentrate diet. Lack of an increase in concentrations of glucose and insulin in serum of cows with the greatest decline in percentage of milk fat casts doubt on the ability of the glucogenic theory to explain milk fat depression completely.

Animal Feed↗

PubMed1995

Patient and doctor delay in acute myocardial infarction: a study in Rotterdam, The Netherlands.

BACKGROUND: Early thrombolytic therapy for patients having a myocardial infarct size and improves survival. AIM: A study was undertaken to examine the components of pre-hospital delay in patients with retrospectively proven myocardial infarction. METHOD: Data were gathered from 300 patients with a documented myocardial infarction admitted to three hospitals in Rotterdam, the Netherlands. Interviews were carried out with patients, questionnaires were given to their spouses or significant others, medical information was provided by cardiologists, and logbook information was gathered from the ambulance service. RESULTS: Half of all patients (51%) called for medical help within 30 minutes of symptom onset. General practitioners arrived within 11 minutes in half of the 257 cases to which they were called. However, in half of the 257 cases, decision making by the general practitioner before the patient was sent to a hospital took more than 82 minutes. The ambulance arrived within 15 minutes in 90% of all 242 cases, while the time required for stabilization of the patient by the ambulance staff and transport to the hospital took a median of 15 minutes. CONCLUSION: Compared with earlier studies, patients with a myocardial infarction called for help sooner. However, it may take a considerable time before the general practitioner refers the patient to hospital. Further research is needed to design measures which will improve the diagnostic power of the general practitioner in order to further reduce pre-hospital delay.

Adult↗

PubMed1994

Psychosocial functioning of young adults after surgical correction for congenital heart disease in childhood: a follow-up study.

To investigate the long-term psychosocial outcome of congenital heart disease, the emotional, intellectual and social functioning of 288 (young) adult patients was assessed with standardized assessment procedures 9-23 years (mean follow-up interval: 16 years) after surgical correction for congenital heart disease in childhood, and compared with that of reference groups. With respect to emotional functioning, the patients reported significantly fewer feelings of hostility, fewer neurotic complaints and a better self-esteem than reference subjects. Overall, the results concerning social functioning showed favourable outcomes on daily activities (school, employment) and leisure-time activities for (young) adults with congenital heart disease. No significant differences were found between scores of different cardiac diagnostic groups on hostility, neuroticism, self-esteem and leisure-time activities. The possibility whether the 'denial'-mechanism might have contributed to the positive outcomes is discussed.

Activities of Daily Living↗

PubMed1994

Home measures of anxiety, avoidant coping and defence as predictors of anxiety, heart rate and skin conductance level just before invasive cardiovascular procedures.

The question was whether anxiety, heart rate and skin conductance level just before invasive cardiac procedures could be predicted by anxiety related measures obtained at patients homes approximately 3 weeks before treatment. Trait measures of avoidant coping and defence were provided by sixty-three male and thirty-three female patients who were scheduled for a diagnostic or interventional heart catheterization. In hospital physiological measures were registered continuously during a 20 min interview and subsequently patients reported their anxiety. Results with hierarchical regression analysis showed that sex, age, medical variables and state anxiety at home explained 62% of state anxiety in hospital. Female sex predicted high anxiety in hospital while advanced age predicted low anxiety. Medical variables and measures of coping and defence did not add a significant contribution to this prediction of anxiety. Skin conductance and heart rate measures could not be predicted by the psychological measures collected at home.

Adaptation, Psychological↗

PubMed1994

Milk fat yield and composition during abomasal infusion of cis or trans octadecenoates in Holstein cows.

The role of trans-C18:1 fatty acids in milk fat depression was examined. Six rumen-cannulated Holstein cows were assigned to two Latin squares with 21-d periods. The common basal diet contained 40% forage and 60% concentrate. Treatments were the uninfused control, 750 g/d of a mixture of cis fat (65% high oleic sunflower oil and 35% cocoa butter), and 750 g/d of a mixture of trans fat (93% shortening and 7% corn oil) infused into the abomasum via a tube that passed through the rumen cannula. Milk yield was similar among treatments. Milk fat percentage and yield were lower, and milk citrate concentration was higher, for the trans than the cis treatment. Changes in the fatty acid composition of milk were similar for the cis and trans treatments compared with the control except for trans-C18:1. The concentration of trans-C18:1 was greater for the cis and trans treatments than for the control and was greater for the trans than for the cis treatment. These data clearly demonstrated that infusion of trans-C18:1 fatty acids into the abomasum depressed milk fat percentage and yield. We speculate that reduced synthesis of fatty acids and reduced activity of acyl transferase in mammary tissue contributed to depressed milk fat percentage for the trans treatment.

Abomasum↗

PubMed1994

Effects of alfalfa and orchardgrass on digestion by dairy cows.

The effects of alfalfa and orchardgrass diets of similar NDF content on ruminal digestion and digesta kinetics as measured using radiolabeled herbage were evaluated in Holstein cows. Two dry and two lactating cows, fitted with ruminal and duodenal cannulas, were fed 12 times daily at restricted and ad libitum intakes, respectively, in a crossover design. Diets were 65:35 and 55:45 hay: concentrate in DM for alfalfa and orchardgrass, respectively, with approximately 19% CP and 42% NDF. The DMI by lactating cows was greater for the alfalfa diet than for the orchardgrass diet. Ruminal and apparent total tract digestibilities of NDF and ADF were less for cows consuming the alfalfa diet than for those on the orchardgrass diet. Particle size of ruminal digesta, based on specific activity from a ruminal pulse-dose of 14C-labeled alfalfa or orchardgrass, did not decrease consistently with time and was greater than fecal particle size, suggesting selective retention of large digesta particles before passage. Ruminal and total tract fractional passage rates of indigestible NDF, based on 14C-labeled forage, did not differ as a result of forage or lactation stage, but NDF gut fill was greater in lactating than in dry cows, indicating that changes in gut fill were related more to differences in intake than to passage rate.

Animal Feed↗

PubMed1994

Direct analysis of body composition of dairy cows at three physiological stages.

Holstein cows were killed at three physiological stages, prepartum (-7 d, n = 10), early lactation (63 d, n = 7), and late lactation (269 d, n = 8), for determination of chemical composition and prediction of energy changes during lactation. Cows were weighed, slaughtered, and separated into five or six fractions, including carcass, gastrointestinal tract, mammary gland, uterus, and fetus (if present); the remainder was noncarcass. Live BW and weight of all empty body components except fat were unaffected by physiological stage. Empty body fat was reduced 42.3 kg for the early lactation cows compared with that of prepartum cows. Fat-free matter was similar across physiological stages; however, the water content of fat-free matter was greater for the prepartum and early lactation cows than for late lactation cows. In early lactation cows, the percentages of total protein were less in carcass and greater in gastrointestinal tissue than in prepartum and late lactation cows, but fat distribution was not affected. The energy values of 9.2 and 5.57 Mcal/kg for fat and protein in tissue, respectively, were determined by regression and used to apportion energy associated with fat, .925, and protein, .07, during lactation using data adjusted for ash. A maximum loss of 442 Mcal of tissue energy by approximately 77 DIM was determined by regression of empty body energy on DIM).

Animals↗

PubMed1993

[Delay in hospitalization of patients with myocardial infarct].

Timely treatment of patients with an evolving myocardial infarction improves the short and long term prognoses. Because of a wrong judgement of the situation by the patient, a significant other or by a general practitioner (GP), treatment may be delayed. To examine this delay 300 patients with myocardial infarction took part in a study between March 1990 and October 1991. After written consent was given, they were interviewed about the pre-hospital period. The significant others received a questionnaire about this period. Medical information was collected from the cardiologists. Fifty percent of all patients called for medical help within 30 minutes. The GP arrived within 11 minutes at the patient's place in 50% of all cases. However, in 50% of all cases the decision making of the GPs before the patient was sent to a hospital required more than 82 minutes. The ambulance arrived within 15 minutes at the patient's place in 90% of all cases. Stabilisation of the patient by the ambulance staff and transport to the hospital took slightly more time. Compared with earlier studies, the patient with a possible myocardial infarction calls for help sooner. Subsequently, in many cases it takes considerable time before the GP refers the patient to a hospital. Further research is needed to improve the diagnostic power of the GP.

Decision Making↗

PubMed1993

Compliance with the medical regimen and partner's quality of life after heart transplantation.

The authors investigated 40 heart transplant recipients and their partners to determine both the partner's quality of life upon transplantation and the experiences of both patient and partner with compliance with the medical regimen. Data on sleep disturbances, social isolation, emotional reactions, depression, anxiety, partner's apprehension, social support and compliance (regarding behaviour and emotional experience) were obtained approximately 21 months after transplantation. Compared to related study groups, partners did not experience more problems in sleep, social isolation, emotional reactions, depression and anxiety. Patients overestimated the apprehension of their partners significantly (p < 0.0001). Generally speaking, with the exception of three items relating to eating fish, canned food and forgetfulness in medicine intake, patients and partners agreed with respect to actual compliance behaviour. Lowest compliance concerned regular physical exercise: 28%. Both patient and partner insisted that they had scarcely any emotional problem with the regimen. Further systematic research is needed to bring to light factors that affect compliance as well as adequate methods to bring about an improvement therein.

Adult↗