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Biomedical subjects

A E Meinders

Publications and source records attributed to A E Meinders.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Metabolic acidosis caused by hyperalimentation; a dangerous complication of parenteral nutrition].

A man aged 46 developed oesophageal obstruction due to carcinoma. He was admitted with dehydration following strongly reduced fluid intake leading to prerenal kidney failure. He had had a renal transplantation, after which a moderate renal insufficiency persisted. During 12 days he received parenteral nutrition upon which he developed severe hyperchloraemic metabolic acidosis. The treatment of this condition consists of discontinuation of the parenteral nutrition and administration of bicarbonate. If the parenteral nutrition needs to be continued, the amount of chloride must be diminished and acetate be added. It is important to monitor the acid-base balance and plasma electrolytes in patients with parenteral nutrition, especially in the presence of renal failure. The patient recovered from the metabolic acidosis but later died of metastatic oesophageal carcinoma.

Acidosis↗
PubMed1999

Prognostic significance of the difference between mixed venous and jugular bulb oxygen saturation in comatose patients resuscitated from a cardiac arrest.

To determine the prognostic significance of the difference between mixed venous and jugular bulb oxygen saturation in survivors and non-survivors of a cardiac arrest, we studied 30 comatose patients (21 non-survivors and 9 survivors) resuscitated from a cardiac arrest. We measured mixed venous oxygen saturation (SmvO2) and jugular bulb oxygen saturation (SjO2) immediately after haemodynamic stabilisation (always within 6 h after cardiac arrest) and 6, 12 and 24 h later. In all patients the SjO2 was about 10% lower than the SmvO2 in the first measurement. In the survivors the SjO2 did not change and remained lower than SmvO2 in eight of nine survivors. However, in the non-survivors the SjO2 increased significantly and was finally higher than the SmvO2 in 12 of 20 patients 24 h after cardiac arrest suggesting a decrease in cerebral oxygen consumption due to extensive loss of functional brain tissue. The positive predictive value of (SmvO2-SjO2) < or = 0 for predicting irreversible brain damage at 24 h after cardiac arrest is 93% and the negative predictive value of (SmvO2-SjO2) > 0 is 53%. Sensitivity and specificity are 65 and 89%, respectively. In a previous study we concluded that early jugular bulb oximetry (within 4 h after cardiac arrest) cannot predict cerebral outcome in comatose patients after cardiac arrest. More studies are needed to clarify the role of prolonged monitoring in the prediction of cerebral outcome after cardiac arrest.

Adult↗
PubMed1999

Serum leptin levels are not influenced by physical training in type 2 diabetes mellitus patients.

AIM: To investigate the effect of physical training on leptin levels in elderly, obese patients with type 2 diabetes mellitus. METHODS: Twenty men and 38 women with type 2 diabetes mellitus with a body mass index (BMI) of > 25 kg/m2 participated in a prospective randomized study. Patients were either on oral glucose lowering drugs (n = 39) or insulin therapy (n = 19). Physical training consisted of a guided, standardized, 6-week training programme performed in the hospital on a cyclo ergometer followed by a 6-week period of guided training at home and ended in a 12-week period of training at home without supervision. Clinical data and laboratory samples including fasting insulin and leptin levels and maximal aerobic capacity were assessed at the start of the study and at 6 and 26 weeks thereafter. RESULTS: Physical training resulted in significantly positive changes in maximal aerobic capacity (VO2max) and maximum work load. No effects of physical training on serum leptin levels and insulin concentrations were detected. Leptin levels were strongly correlated with body mass index (r = 0.63), body fat content (r = 0.61), and fasting insulin concentrations (r = 0.38). Women had threefold higher leptin levels than men. No differences in leptin levels between patients on insulin therapy and patients on oral glucose lowering drugs were found. CONCLUSIONS: No effect of physical training on leptin levels was detectable in elderly, obese type 2 diabetes mellitus patients.

Aged↗
PubMed1999

Influence of obesity and body fat distribution on growth hormone kinetics in humans.

We studied the kinetics of exogenous recombinant 22-kDa human growth hormone (rhGH) in premenopausal women with upper body obesity (UBO), lower body obesity (LBO), or normal body weight. A bolus of 100 mU rhGH was administered during a continuous infusion of somatostatin to suppress endogenous GH secretion. GH kinetics were investigated with noncompartmental analysis of plasma GH curves. GH peak values in response to GH infusion and plasma half-life of GH were not significantly different between normal weight and obese subjects. In contrast, GH clearance was 33% higher in LBO women and 51% higher in UBO women compared with clearance in normal weight controls. The difference in clearance between LBO and UBO was not statistically significant. Altered GH clearance characteristics contribute to low circulating GH levels in obese humans. Body fat distribution does not appear to affect GH kinetics.

Adipose Tissue↗
PubMed1999

Severe hyperlipidemia in apolipoprotein E2 homozygotes due to a combined effect of hyperinsulinemia and an SstI polymorphism.

More than 90% of patients with type III hyperlipoproteinemia are homozygous carriers of the apolipoprotein (apo) E*2 allele. The great majority of these apoE2(Arg158-->Cys) homozygotes in the general population, however, are normolipidemic. Apparently, expression of the hyperlipidemic state requires additional genetic and/or environmental factors, suggesting a multifactorial etiology. To elucidate these additional risk factors, we analyzed normolipidemic and hyperlipidemic apoE2 homozygotes. Hyperinsulinemia was observed in 27 of 49 apoE2 homozygotes and associated with elevated lipid levels: hyperinsulinemic apoE2 homozygotes had type III hyperlipoproteinemia 6 times more often than apoE2 homozygotes with normal insulin levels (odds ratio 6.2, P=0.02). We screened the normolipidemic and hyperlipidemic apoE2 homozygotes for common variants in candidate genes involved in lipolysis-the APOA1-C3-A4 gene cluster, lipoprotein lipase, and hepatic lipase-and analyzed for associations with the expression of hyperlipidemia. In the hyperinsulinemic group, the 7 carriers of the SstI polymorphism (S2) in the APOC3 gene displayed severely elevated VLDL cholesterol (P(insulin by SstI)<0.001) and VLDL triglyceride (P(insulin by SstI)<0.01) and low levels of HDL (P(insulin by SstI)<0.02). In the normoinsulinemic group, no such relation of the SstI polymorphism with hyperlipidemia was observed. These data provide the first evidence for a combined effect of hyperinsulinemia and the SstI polymorphism on the expression of hyperlipidemia in apoE2 homozygotes.

Adult↗
PubMed1998

[Clinical thinking and decision making in practice. A patient with pain in the upper abdomen].

A 74-year-old woman was admitted because of abdominal pain. A few weeks before this admission she had had a cerebral infarction in the right hemisphere, reflected by a left sided paralysis, dysarthria, depression and a slight cognitive disorder. The night before admission she woke up from a sharp, continuous pain in the right upper abdomen. Physical examination disclosed pain in the right upper abdomen on palpation. Laboratory tests showed a slight elevation of all 'liver' enzymes. A differential diagnosis of cholecystitis or pyelonephritis was made. Additional tests did not confirm either of these diagnoses. Because of immobilisation pulmonary embolism was then suspected. This diagnosis was confirmed by scintigraphy. The patient was treated and made a full recovery. Diagnostic errors can be made by faulty triggering and omitting verification. The diagnostic strategy for pulmonary embolism is a ventilation perfusion scan, which is followed in case of a non high-probability result by pulmonary angiography. It is emphasized that the presentation of pulmonary embolism can be aspecific.

Abdominal Pain↗
PubMed1998

[Clinical thinking and decision making in practice. A patient with icterus].

A 55-year-old man was admitted because of cholestatic jaundice. Extrahepatic obstruction and viral causes were excluded. A diagnosis of liver damage due to the combination preparation amoxicillin and clavulanic acid (Augmentin) was made. The patient had an uneventful recovery. It is pointed out that in case of cholestatic jaundice drug-induced cholestasis should be suspected early in the course. History taking is an important tool. If a suspected drug is found other causes of the disease can be excluded with simple tests.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed1998

[Overweight. III. Therapeutic strategies for weight reduction].

Obesity is a major health hazard. It increases the risk of cardiovascular disease, diabetes, mellitus and various malignancies. Minor weight loss (5-10% of body weight) appears to reduce this risk. (Very) low calorie diets alone are not effective in the long run. Regular physical exercise and behavioral interventions improve the effect of calorie restriction to an extent that is beneficial to health. Long term drug treatment is not recommended for the treatment of obesity. A number of appetite suppressants has been withdrawn from the market because of serious side effects during long term (> 3 months) use. Also, data on the efficacy of long term (> 1 year) drug treatment of obesity are not available. However, short term use to support calorie restriction might be helpful. Bariatric surgery is indicated and reasonably safe for morbidly obese patients (body mass index > or = 40 kg/m2), particularly for those who have other risk factors for cardiovascular disease. Adjustable gastric banding appears to be an effective and safe alternative to (vertical) gastroplasty.

Anti-Obesity Agents↗
PubMed1998

[Addisonian crisis provoked by levothyroxine substitution therapy].

A women aged 36 with a positive family anamnesis for autoimmune endocrine diseases and a history of thyroid diseases, developed major complaints of general malaise, orthostatic hypotension and loss of appetite after the start of a treatment with levothyroxin because of (sub)clinical hypothyroidism. She was found to suffer from primary adrenocortical insufficiency masked by excessive use of liquorice and a lowered metabolism, but which via the suppletion with thyroid hormone had led to an addisonian crisis.

Addison Disease↗
PubMed1998

[Clinical thinking and decision making in the practice. A patient with fever of unknown origin].

A 75-year-old woman was admitted because of fever of unknown origin (FUO). In the year before the current admission she developed myalgias and was treated for polymyalgia rheumatica with low-dose prednisone. Her complaints persisted and prednisone was discontinued. Five months before the present admission she developed fever (37.7-38.9 degrees C), malaise, fatigue and occipital headache. Laboratory tests showed an elevated erythrocyte sedimentation rate (98 mm in the first hour) and a severe hypochromic, slightly microcytic, anaemia. Although a recent temporal artery biopsy was negative, a second biopsy was taken which showed giant cell arteritis. The patient was treated with high-dose prednisone (60 mg daily) and made a full recovery. It is emphasized that temporal arteritis is a common cause of FUO in the elderly.

Aged↗
PubMed1998

[The hyperglycemic dehydration syndrome].

Two patients, men aged 47 and 64 years, were found in a comatose condition in their homes, after a period of fatigue, polyuria and polydipsia. They had not been known to suffer from diabetes mellitus, but now displayed a hyperglycaemic hyperosmolar non-ketoacidotic disorder as the first manifestation of diabetes mellitus type 2. In that condition, just sufficient insulin is present to counteract ketone production, but not enough to prevent hyperglycaemia. Neurological and thromboembolic manifestations, possibly fatal, may result from severe dehydration brought about by a vicious circle in which osmotic diuresis reduces the effective circulating volume, causing renal function to decrease and hyperglycaemia to increase even more. Both patients recovered fully after adequate treatment with solutions of NaCl and glucose.

Dehydration↗
PubMed1998

[Clinical decision making in family practice. A patient with abdominal pain and chills].

An 82-year-old man was admitted because of abdominal pain and a shaking chill. His medical history revealed ileocecal resection because of ileitis associated with a Yersinia infection 3 years before admission. One year later he was readmitted because of bowel obstruction due to recurrent ileitis. He was treated with trimethoprim-sulfamethoxazole for two weeks because of positive serological tests for Yersinia and made a full recovery except for chronic diarrhoea. On the current admission, stool cultures yielded Campylobacter upsaliensis. Further analysis showed severe non-specific ulcerative ileitis without colitis. A diagnosis of Crohn's disease was made. The patient was treated with prednisone and mesalazine and made a full recovery. The chronic diarrhoea disappeared. The course was complicated by a cerebro-vascular thrombosis and severe thrombocytosis due to polycythaemia vera. Treatment with hydroxyurea was effective in lowering the thrombocyte count.

Abdominal Pain↗
PubMed1998

Similar response to simvastatin in patients heterozygous for familial hypercholesterolemia with mRNA negative and mRNA positive mutations.

In patients heterozygous for familial hypercholesterolemia, the low-density lipoprotein (LDL) cholesterol lowering effect of beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors may depend on the nature of the mutation in the LDL receptor gene. To test this hypothesis, we compared the response to simvastatin, 20 mg daily for 9 weeks, between heterozygous carriers of functionally different classes of mutations, i.e. mRNA negative or mRNA positive mutations. Out of 116 consecutive, unrelated patients with familial hypercholesterolemia, 27 patients were selected for molecular analyses: 14 patients with mRNA negative and 13 with mRNA positive mutations. Before simvastatin treatment, patients with mRNA negative mutations had higher levels of LDL cholesterol, lower levels of high-density lipoprotein (HDL) cholesterol and significantly more often tendon xanthomas, compared to patients with mRNA positive mutations. Simvastatin reduced the mean fasting LDL cholesterol levels to a similar percentage in the mRNA negative and mRNA positive patients (37, 36%, respectively, 95% CI of difference--8 to 5%, P = 0.2). This effect was similar to the 37% decrease observed in our total series of patients with familial hypercholesterolemia (n = 116). The increase in mean concentration of HDL cholesterol was greater in the mRNA negative group than in the mRNA positive group (16, 0%, respectively, 95%, CI of difference 8-25%, P = 0.002) independent of the response of total triglycerides to simvastatin. The percentage LDL cholesterol lowering response varied among multiple carriers of the same mutation, even in the case of mRNA negative mutations. We conclude that the percentage LDL lowering response to simvastatin treatment was similar in patients with mRNA negative and mRNA positive mutations. Moreover, variation of this response within multiple carriers of the same mutation suggests an influence of additional factors.

Anticholesteremic Agents↗
PubMed1998

Can intra-operative GH measurement in acromegalic subjects predict completeness of surgery?

OBJECTIVE: Results of trans-sphenoidal pituitary surgery, in terms of long-term cure, vary considerably between centres. Additional techniques, which can assist the neurosurgeon in deciding whether surgery is complete or not, might therefore be important. One such potential tool is the intra-operative measurement of GH and calculating the plasma half-life from the plasma samples obtained after the presumed complete resection of the adenoma. METHODS: GH half-life was calculated from 5-10 min plasma samples after adenomectomy in 20 patients. GH was measured with a sensitive and rapid IFMA, and the results could be reported within 30 min, but were not used in this study for per-operative decisions. Cure was defined by a glucose suppressed plasma GH concentration below 1 mU/l (0.38 microgram/l) during follow-up studies and a normal plasma IGFI concentration. RESULTS: In 13 cured patients the plasma half-life was 22.2 +/- 1.9 min (range 14-40.6). In three non-cured patients the plasma half-life could not be calculated, and in four other patients the plasma half-life was 35.8 +/- 5.9 min (range 25.8-51 min). By applying 25 min as the upper normal limit for the GH plasma half-life, the sensitivity was 77%, specificity 100%, and positive predictive value 100%. CONCLUSION: Per-operative plasma GH monitoring is a potentially useful tool for determining the completeness of trans-sphenoidal surgery in acromegaly.

Acromegaly↗
PubMed1998

A comparison of near-infrared spectroscopy and jugular bulb oximetry in comatose patients resuscitated from a cardiac arrest.

One cause of cerebral damage in comatose patients resuscitated from a cardiac arrest is cerebral ischaemia occurring during the postresuscitation period. Near-infrared spectroscopy has been advocated as a useful monitor of brain oxygenation, but data on clinical use in comatose postarrest patients are not available. Therefore, we compared regional oxygen saturation measured with the INVOS 3100 with global oxygen saturation measured using jugular bulb oximetry in 10 comatose patients successfully resuscitated from an out-of-hospital cardiac arrest. Our data show that, in most patients, there is a significant difference between the two methods. The INVOS 3100 over-read at low jugular bulb saturations (< 60%) and under-read at high jugular bulb saturations (> or = 60%). During hypoventilation we found a significant increase in regional oxygen saturation. This increase was significantly correlated with the rise in cerebral blood flow and cardiac index, indicating that regional oxygen saturation is influenced by both cerebral and extracerebral components. We conclude that regional cerebral oxygen saturation measured with the INVOS 3100 cannot be compared with global cerebral oxygen saturation measured with jugular bulb oximetry in comatose patients resuscitated from a cardiac arrest. This may be due to characteristics of the INVOS 3100 or to the distribution of cerebral blood flow after cardiac arrest.

Aged↗
PubMed1998

No effect of consumption of green and black tea on plasma lipid and antioxidant levels and on LDL oxidation in smokers.

Intake of flavonoids is associated with a reduced cardiovascular risk. Oxidation of LDL is a major step in atherogenesis, and antioxidants may protect LDL from oxidation. Because tea is an important source of flavonoids, which are strong antioxidants, we have assessed in a randomized, placebo-controlled study the effect of consumption of black and green tea and of intake of isolated green tea polyphenols on LDL oxidation ex vivo and on plasma levels of antioxidants and lipids. Healthy male and female smokers (aged 34+/-12 years, 13 to 16 per group) consumed during a 4-week period 6 cups (900 mL) of black or green tea or water per day, or they received as a supplement 3.6 grams of green tea polyphenols per day (equivalent to the consumption of 18 cups of green tea per day). Consumption of black or green tea had no effect on plasma cholesterol and triglycerides, HDL and LDL cholesterol, plasma vitamins C and E, beta-carotene, and uric acid. No differences were found in parameters of LDL oxidation. Intake of green tea polyphenols decreased plasma vitamin E significantly in that group compared with the control group (-11% P=.016) but had no effect on LDL oxidation ex vivo. We conclude that consumption of black or green tea (6 cups per day) has no effect on plasma lipids and no sparing effect on plasma antioxidant vitamins and that intake of a high dose of isolated green tea polyphenols decreases plasma vitamin E. Although tea polyphenols had a potent antioxidant activity on LDL oxidation in vitro, no effect was found on LDL oxidation ex vivo after consumption of green or black tea or intake of a green tea polyphenol isolate.

Adult↗
PubMed1998

Circadian rhythm of plasma leptin levels in upper and lower body obese women: influence of body fat distribution and weight loss.

Plasma leptin concentrations were measured every 20 min for 24 h in eight normal weight women and in eight upper body and eight lower body obese women matched for body mass index. The circadian rhythm of leptin, which could mathematically be described by a cosine, was characterized by an acrophase just after midnight in all subjects. The amplitude of a cosine fit as well as the average 24-h leptin concentration were increased by 280% and 420%, respectively, in obese compared to normal weight women. All characteristics of leptin concentration profiles were similar in upper body and lower body obese women, except for a significantly higher amplitude in the lower body obese group. Visceral and sc body fat depots were measured using magnetic resonance imaging in all three groups. Average 24-h leptin concentrations were strongly correlated with sc fat (r = 0.84), whereas visceral fat was not an independent predictor of the plasma leptin level. A loss of 50% of the overweight was associated with a 55% decrease in the average 24-h leptin concentrations in obese women (95% confidence interval, 12.3, 26.6), whereas the characteristics of the circadian rhythm of leptin remained unchanged. Finally, it was observed that a fasting plasma leptin concentration is not an acceptable indicator of the average leptin concentration over 24 h.

Adipose Tissue↗