Biomedical subjects

G A Ponjee

Publications and source records attributed to G A Ponjee.

12 recordsLinked to original sources

PubMed1996

Haemolytic disease of the newborn due to anti-K antibodies.

We describe a case of intrauterine foetal death at 32 weeks gestation with signs of hydrops foetalis without erythroblastosis. The hydrops foetalis appeared to be caused by blood group incompatibility. Irregular antibodies of anti-K specificity were found in the serum of the mother, while the father was positive for the K-antigen. The antibody dependent cell-mediated cytotoxicity (ADCC) test with serum of the mother was positive. This case shows the characteristics of haemolytic disease of the newborn by anti-K. Moreover, it underlines the necessity of both adequate follow-up of individual cases, and screening for irregular antibodies in all pregnancies as well as central registration of screening results.

Adult↗

PubMed1996

Regular physical activity and changes in risk factors for coronary heart disease: a nine months prospective study.

This study reports the non-acute effects of a long-term training programme of increasing intensity on some cardiovascular risk factors and the interrelation between these risk factors. Twenty sedentary men and 14 sedentary women were trained 3 to 4 times a week for nine months. After 36 weeks all individuals ran a half marathon run. The Wmax, weight, body mass index, systolic and diastolic blood pressure were recorded. The concentrations of fibrinogen, tissue plasminogen activator, plasminogen activator inhibitor, triacylglycerols, total cholesterol, LDL cholesterol, HDL cholesterol and lipoprotein(a) were measured. The training programme induced a median increase in Wmax of 12% in the male group (from 226 to 251.5 Watt) and of 18% in the female group (from 160 to 188.5 Watt). These increases inn Wmax did not correlate with any other property under investigation in this study. Blood pressure was not altered, but body weight and body mass index were significantly decreased in the male group (from 74.6 to 72.2 kg and from 23.1 to 22.0 kg/m2, respectively) at the end of the training programme and decreased non-significantly in the female group (from 63.0 to 60.7 kg and from 21.6 to 21.5 kg/m2, respectively). In the male group total cholesterol, low density lipoprotein cholesterol and triacylglycerols decreased significantly under the influence of the training sessions. Furthermore, in both groups, a great decrease in plasma plasminogen activator inhibitor concentrations was noticed: in men from 22.5.10(3) AU/l to 4.5.10(3) AU/l and in women from 18.7 x 10(3) AU/l to 5.1 x 10(3) AU/l. However, the changes in the lipid and fibrinolytic quantities were not correlated with each other. Initial total cholesterol, LDL cholesterol and triacylglycerol levels correlated significantly with systolic blood pressure, while diastolic pressure was correlated to tissue plasminogen activator. Since tissue plasminogen activator also was significantly related to triacylglycerols, a trias existed between primary risk factors like blood pressure, lipid levels and fibrinolysis. In contrast, the changes in these properties under the influence of physical training were not interrelated. Median serum lipoprotein(a) concentrations were significantly increased in both men and women five days before the half marathon run: from 32 mg/l to 39 mg/l in men, and from 65 mg/l to 125.5 mg/l in women. Concomitantly, median fibrinogen concentrations were significantly elevated in men (from 2.32 g/l to 3.10 g/l) and non-significantly in women (from 2.62 g/l to 2.93 g/l), although no correlation existed between the changes in these properties. In conclusion, the nine months exercise programme increased the aerobic fitness in both men and women as indicated by the Wmax increase. This improvement coincided but was not correlated with beneficial changes in several anthropometric, lipid and fibrinolytic properties. Improvement in the risk factors under investigation was more pronounced in men than in women. The changes in lipid and haemostasis properties did not correlate with each other. The increases in lipoprotein(a) and fibrinogen concentrations, both atherogenic indices, could actually present a normal physiological response to the physical strain of exercise training of increasing workload.

Blood Pressure↗

PubMed1996

A Dutch family with Hb Atlanta [beta 75(E19)Leu-->Pro].

We have investigated four members of a three-generation Dutch family for a suspected hemoglobinopathy. Chronic hemolysis and a moderate macrocytic normochromic anemia with slight morphological abnormalities of the red cells was observed in all four. Hemoglobin chain synthesis in vitro and separation of the globin chains by reversed phase high performance liquid chromatography revealed an abnormal beta-globin species in addition to the normal alpha and beta chains. The decreased amount of normal beta-globin and the low amount of unidentified protein suggested an unstable beta-globin variant. An abnormal band was detected by isoelectrofocusing. In one family member tested, the hemoglobin in an erythrocyte lysate had decreased heat stability. All carriers were positive in the isopropanol hemoglobin instability test. Treatment of erythrocytes with methylviolet gave rise to microgranular inclusions. Nucleotide sequencing of the polymerase chain reaction-amplified beta-globin gene revealed a heterozygous single base pair T-->C mutation at codon 75, which changes the normal CTG codon for leucine to a CCG codon for proline. This variant has previously been identified as Hb Atlanta or beta 75(E19)Leu-->Pro. The mutation creates a new Msp I restriction site, which was used to confirm the diagnosis in all four family members. A quantitative reverse transcriptase polymerase chain reaction procedure for determining the relative amounts of mRNA transcripts for the normal and abnormal globin chain showed a comparable stability for both transcripts.

Aged↗

PubMed1995

Long-term physical exercise and lipoprotein(a) levels in a previously sedentary male and female population.

We investigated the effect of long-term physical exercise on serum lipoprotein(a) levels. 21 sedentary men and 15 sedentary women were trained three to four times a week with increasing intensity during 9 months. After 24 weeks all subjects ran a 15 km race and after 36 weeks a half marathon run (21 km). Blood samples were drawn before the training programme, 5 days before both races and 5 days after the half marathon run. Median (interquartile range) pre-training values in the male group were 32 (11-63) mg/L and in the female group 65 (23-199) mg/L. After 24 weeks of training, serum lipoprotein(a) concentrations had risen significantly in both male and female groups. Moreover, after 36 weeks of training, in preparation for the half marathon competition, median serum lipoprotein(a) rose almost twofold in both groups and was still elevated 5 days later. This study demonstrates that an exercise programme which includes running of increasing distances significantly increases serum lipoprotein(a) concentration.

Adult↗

PubMed1995

Effects of long-term exercise of moderate intensity on anthropometric values and serum lipids and lipoproteins.

The influence of endurance training on serum lipids and lipoproteins was investigated in 20 sedentary males and 14 sedentary females. The total group was trained 3 to 4 times a week for 9 months. After 24 weeks all subjects ran a 15 km-race and after 36 weeks a half-marathon (21 km) race. Anthropometric values were determined before and after the training programme. Blood samples were drawn before the start of the training programme and, in order to avoid the measurement of acute effects, 5 days before both races. In the male group, median body weight and body mass were significantly decreased (p < 0.01) after nine months of training, while in the female group body weight and body mass index remained essentially unchanged. Percentage body fat, measured by skinfold thickness was significantly decreased in both groups at the end of the training programme. During the training period, median serum total cholesterol, low density lipid cholesterol and triacylglycerol concentrations decreased significantly (p < 0.01) in the male group, while in the female population the median serum lipid- and lipoprotein concentrations did not differ from pre-training values. The changes in serum lipids or lipoproteins did not correlate significantly with changes in body weight, body mass index or percentage body fat. Stepwise multiple regression showed that these changes were mostly dependent on initial concentrations in serum. Finally, no significant increase in median high density lipid cholesterol was observed in either the male or female group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

High plasma antithrombin levels in acute hepatitis A.

BACKGROUND: Laboratory testing of antithrombin serves to demonstrate a decreased concentration that is indicative of a thrombotic tendency. We report unexpected high levels of antithrombin in a patient with hepatitis A. METHODS: A 37-year-old woman with a 4-week history of acute hepatitis A was studied. The diagnosis of cholestatic hepatitis A was confirmed by positive serology and liver biopsy. The patient recovered completely within 6 months. RESULTS: Antithrombin activity was increased (234%; reference range, 80-120%). This high activity was confirmed by an antithrombin antigen of 210%. On recovery antithrombin activity returned to normal. CONCLUSIONS: We are unaware of other reports of such high levels of antithrombin, in particular in patients with hepatitis A. It is not clear whether the high concentration observed in this case is due to an acute-phase reaction or to impaired clearance by the liver. The presence of a molecular variant with different secretion characteristics is unlikely, since antithrombin activity returned to normal on recovery, suggesting base-line values within the normal range.

Acute Disease↗

PubMed1994

Androgen turnover during marathon running.

The purpose of the study was to investigate the effect of prolonged physical stress on peripheral androgen turnover. Venous blood samples were taken from 18 athletes 24 h before finishing a competitive marathon run and directly after running the race. Serum cortisol, testosterone (T), dehydroepiandrosteronesulfate (DHEAS), sex hormone binding globulin (SHBG), and 5 alpha-androstane- 3 alpha, 17 beta-diolglucuronide (3 alpha-AdiolG) were determined and corrected for hemoconcentration. Marathon running caused a rise in serum cortisol concentration in all athletes. Furthermore, a significant (P < 0.01) rise in serum T and T-index (index of free T) was observed. The significant (P < 0.01) rise in serum DHEAS concentration, a mainly adrenal cortical androgen, pointed toward a stimulation of the adrenal cortex or a reduced hepatic metabolic clearance rate. Finally, 3 alpha-AdiolG, an androgen metabolite exclusively formed in peripheral tissues, was increased in the sera of all athletes. These results suggest that marathon running leads to increased concentrations of serum adrenal and gonadal androgens. The simultaneously increased 3 alpha-AdiolG levels may be caused by increased androgen turnover in peripheral tissues containing 5 alpha-reductase.

Adult↗

PubMed1993

Prolonged endurance exercise and blood coagulation: a 9 month prospective study.

To study the long-term overall effect of physical exercise on blood coagulation, 20 sedentary males and 15 sedentary females were trained three to four times a week with increasing intensity for 9 months. After 24 and 36 weeks all subjects ran a 15 km and a half-marathon (21 km) race, respectively. Blood samples were drawn before the training programme, 5 days before both races and 5 days after the half-marathon run. Plasma factor VIII coagulant activity and von Willebrand factor antigen concentration did not increase during the training programme. In both males and females plasma fibrinogen concentration was not enhanced after 24 weeks of training but increased in preparation for the 21 km race and was still raised significantly (P < 0.01) 5 days later. No significant changes in plasma thrombin-antithrombin III concentrations were observed in either group during the training programme. The results of this study demonstrate that an exercise programme of increasing intensity induces physical stress which has significant effects on plasma fibrinogen concentrations, even at rest. However, in contrast to acute post-exercise effects, a regular physical fitness programme does not induce a long-term activation of the haemostatic system.

Adult↗

PubMed1991

Androstanediolglucuronide: a parameter for peripheral androgen activity before and during therapy with cyproterone acetate.

Serum 5 alpha-androstane-3 alpha,17 beta-diolglucuronide (3 alpha-AdiolG) levels were measured and the degree of hirsutism was scored in female outpatients complaining of excessive hair growth before and during treatment with cyproterone acetate. In a group of 16 patients with idiopathic hirsutism and in a group of 9 patients with either polycystic ovary syndrome and hirsutism or 21-hydroxylase deficiency and hirsutism, the serum 3 alpha-AdiolG levels were significantly increased (p less than 0.01) as compared with the serum 3 alpha-AdiolG level in a control group of 13 apparently healthy women: 3 alpha-AdiolG levels, median (range), being 5.3 (2.3-7.8) nmol/l, 8.5 (4.1-10.4) nmol/l, and 2.9 (1.5-5.2) nmol/l, respectively. In contrast to a previous report, no correlation was found between the serum 3 alpha-AdiolG levels and the Quetelet Index (N = 18, R = 0.42, p greater than 0.05), indicating an apparent ineffectiveness of the excessive androgen turnover in fat tissue. The use of the anti-androgen drug cyproterone acetate alone or in combination with ethinylestradiol in reverse sequential therapy did lower the 3 alpha-AdiolG levels significantly (p less than 0.01) together with a significant decrease (p less than 0.01) in hirsutism score. From the results of this study we therefore conclude that 3 alpha-AdiolG can be used as a parameter for peripheral androgen action before and during treatment with anti-androgens.

Androgen Antagonists↗

PubMed1991

One-step chromogenic equivalent of activated partial thromboplastin time evaluated for clinical application.

We evaluated the clinical usefulness of a recently developed semi-automated one-step chromogenic equivalent of activated partial thromboplastin time (APTT; Behring). This simple test is easily adaptable for automation. Generally, the results with this chromogenic one-step APTT were at least as precise as those obtained with comparative coagulometric methods. The chromogenic one-step APTT showed, both in vitro and in vivo, adequate sensitivity to congenital intrinsic factor deficiency but no sensitivity to Factor VII deficiency. Unlike a two-step coagulometric APTT (Dade), the one-step chromogenic APTT seemed sensitive to activation products of the contact system, which are present in immunoadsorbed factor-deficient plasma. The in vitro sensitivity of the chromogenic APTT to heparin was comparable with that of a coagulometric APTT, but the sensitivity to heparin in patients' samples differed slightly. The chromogenic APTT is relatively insensitive to anomalies in the fibrinogen-fibrin conversion. Finally, we observed discrepancies between the chromogenic and coagulometric APTT results for plasma of patients with disseminated intravascular coagulation. We conclude that this one-step chromogenic APTT warrants further evaluation for possible use as a routine test for the clinical laboratory.

Amino Acid Sequence↗

PubMed1985

Investigations on the insertion of the mitochondrial precursor protein apocytochrome c into model membranes.

Different aspects of the interaction of apocytochrome c and model membranes composed of negatively charged lipids, were studied in order to get insight into the nature of this interaction. The effect of the protein on the lipid packing properties are revealed by DSC, ESR and monolayer techniques. These experiments clearly demonstrate that upon electrostatic interaction with the negatively charged phospholipids, apocytochrome c is able to penetrate into the hydrophobic region of the model membrane. In the case of 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol, this results in a perturbation of 160 lipid molecules per apocytochrome c molecule. Most likely, apocytochrome c disrupts the formation of the gel phase and restricts the lipid chain motion above the gel to liquid-crystalline phase transition. Tryptophan fluorescence measurements confirm that at least a part of the protein penetrates into the bilayer, and suggest that after this penetration, the tryptophan (residue no. 59) is located in the glycerol backbone region of the phospholipids. Although the secondary structure of apocytochrome c is predicted to contain about 35% of alpha-helical structure, the CD pattern of an aqueous solution of the protein is featureless. However, negatively charged lipids are able to express this alpha-helical potency in the apocytochrome c, which might be important for the insertion of the protein into lipid membranes.

Animals↗

PubMedDate not supplied

Prolonged physical conditioning and blood platelet release markers: a longitudinal study.

To study the long-term non-acute effect of endurance physical exercise on blood platelet activation, 20 sedentary males and 14 sedentary females were trained 3 to 4 times a week for 9 months. After 24 weeks all subjects ran a 15-km race; and after 36 weeks a half-marathon (21 km) race. Blood samples were drawn before the training programme and 5 days after both races. Median (interquartile range) platelet factor 4 and beta-thromboglobulin pretraining values for the total group were 9 (5-35) and 69 (40-495) IU/ml, respectively. During the course of the training programme, plasma platelet factor 4 concentrations rose steadily and significantly in both the male and female group (p < 0.05), together with a non-significant rise in plasma beta-thromboglobulin. At the end of the training procedure, 5 days after the half-marathon run, median (interquartile range) plasma factor 4 and beta-thromboglobulin concentrations for the total group were 150 (62-198) and 156 (84-288) IU/ml, respectively. No difference existed in median platelet factor 4 and beta-thromboglobulin concentrations of the male and female population before or during the training programme. In summary, the results of this study demonstrate that prolonged physical conditioning of increasing intensity is mainly associated with an elevation of the platelet protein platelet factor 4.

Adult↗