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Biomedical subjects

R Imoberdorf

Publications and source records attributed to R Imoberdorf.

At least 19 recordsLinked to original sources

[Eating and drinking during aging].

The retirement is a good moment in life to mirror one's health behaviour in regard to eating habits and physical activity. Based on the literature we recommend the Mediterranean "diet" in all ages. This diet is characterized by the intake of fresh fruit, vegetables, cereals, olive oil, fish, little meat, legumes, spices and herbs such as basil and garlic. A glass wine a day is legitimate. In increasing age total energy needs are decreasing. Therefore the energy intake has to be adjusted. Caloric restriction per se is a powerful means to reduce cardiovascular morbidity and mortality. However, not only the eating habits but also the entire lifestyle are important factors to influence cardiovascular mortality. Thus, the "low risk factors", i.e. Mediterranean diet, moderate alcohol consumption, physical activity and non-smoking must be controlled to improve health. In the HALE project the control of these factors reduced over-all mortality by 65 percent!

Aging↗

[Nutritional support for critically ill and dying patients].

There is evidence in the literature that oral nutritional supplements, total enteral and parenteral nutrition can expand life expectancy and improve quality of life in patients suffering from undernutrition. In the present review, we outline whether these treatments regimens are also effective in severely ill patients. Moreover, the usefulness of nutritional interventions in patients sick unto death, e.g. by stroke, cancer or dementia, is broadly discussed. The controversy about terminal dehydration is shortly reviewed.

Critical Care↗

Determination of plasma volume by indocyanine green--validation of the method and use in patients after cardiopulmonary bypass.

OBJECTIVE: Validation of plasma volume (PV) determination by indocyanine green (ICG) in comparison to the gold-standard method with radioiodinated albumin, and investigation of the effect of commonly used plasma expanders (albumin, hydroxyethyl starch, and polygelatine) on PV in the early postoperative phase in patients undergoing cardiac surgery. DESIGN: Prospective clinical study. SETTING: Department of medicine and intensive care unit at a university hospital. PATIENTS AND PARTICIPANTS: Ten healthy volunteers and 21 patients after elective open-heart surgery. MEASUREMENTS AND RESULTS: PV of subjects was measured by i.v. injecting 5 microCi [125I]albumin (I-ALB). One hour later, PV was determined by a peripheral i. v. injection of 0.25 mg/kg body weight ICG (ICG1). In five subjects PV was measured repeatedly by ICG (ICG2) 1 h after ICG1. Mean PV of I-ALB and ICG1 or ICG2 showed consistent results. Further, we investigated central vs peripheral intravenous injection of ICG in six patients after open-heart surgery compared to [125I]albumin. There was no difference between mean PV measured by [125I]albumin and peripheral ICG (P = 0.40). PV determined by central injection of ICG was significantly higher than by the other methods. In 15 patients PV was determined by [125I]albumin. Thereafter, patients were randomly divided into three groups. Group ALB was infused with 1.75 ml/kg body weight human albumin 20%, group HAES with 5.25 ml/kg body weight hydroxyethyl starch 6%, and group HAEM with 7.0 ml/kg body weight polygelatine 3.5%. PV was measured 1 h and 4 h after infusion by ICG. There were no significant changes in PV between the groups. CONCLUSIONS: PV determination by peripheral i. v. injection of ICG produced reliable and consistent results when a reactive hyperaemia was produced by a tourniquet prior to injection. Therefore, central venous injection of ICG may not be prerequisite for precise measurements of PV. The expected acute increase in PV after infusion of commonly used plasma expanders after cardiac surgery was not found.

Adult↗

Acute metabolic acidosis decreases muscle protein synthesis but not albumin synthesis in humans.

Chronic metabolic acidosis induces negative nitrogen balance by either increased protein breakdown or decreased protein synthesis. Few data exist regarding effects of acute metabolic acidosis on protein synthesis. We investigated fractional synthesis rates (FSRs) of muscle protein and albumin, plasma concentrations of insulin-like growth factor-I (IGF-I), thyroid-stimulating hormone (TSH), and thyroid hormones (free thyroxin [fT(4)] and triiodothyronine [fT(3)]) in seven healthy human volunteers after a stable controlled metabolic period of 5 days and again 48 hours later after inducing metabolic acidosis by oral ammonium chloride intake (4.2 mmol/kg/d divided in six daily doses). Muscle and albumin FSRs were obtained by the [(2)H(5)ring]phenylalanine flooding technique. Ammonium chloride induced a significant decrease in pH (7.43 +/- 0.02 versus 7.32 +/- 0.04; P < 0.0001) and bicarbonate concentration (24.6 +/- 1.6 versus 16.0 +/- 2.7 mmol/L; P < 0.0001) within 48 hours. Nitrogen balance decreased significantly on the second day of acidosis. The FSR of muscle protein decreased (1.94 +/- 0.25 versus 1.30 +/- 0.39; P < 0.02), whereas the FSR of albumin remained constant. TSH levels increased significantly (1.1 +/- 0.5 versus 1.9 +/- 1.1 mU/L; P = 0.03), whereas IGF-I, fT(4), and fT(3) levels showed no significant change. We conclude that acute metabolic acidosis for 48 hours in humans induces a decrease in muscle protein synthesis, which contributes substantially to a negative nitrogen balance. In contrast to prolonged metabolic acidosis of 7 days, a short period of acidosis in the present study did not downregulate albumin synthesis.

Acidosis↗

Enhanced synthesis of albumin and fibrinogen at high altitude.

The acute effects of active and passive ascent to high altitude on plasma volume (PV) and rates of synthesis of albumin and fibrinogen have been examined. Measurements were made in two groups of healthy volunteers, initially at low altitude (550 m) and again on the day after ascent to high altitude (4,559 m). One group ascended by helicopter (air group, n = 8), whereas the other group climbed (foot group, n = 9), so that the separate contribution of physical exertion to the response could be delineated. PV was measured by dilution of (125)I-labeled albumin, whereas synthesis rates of albumin and fibrinogen were determined from the incorporation of isotope into protein after injection of [ring-(2)H(5)]phenylalanine. In the air group, there was no change in PV at high altitude, whereas, in the foot group, there was a 10% increase in PV (P < 0.01). Albumin synthesis (mg. kg(-1). day(-1)) increased by 13% in the air group (P = 0.058) and by 32% in the foot group (P < 0.001). Fibrinogen synthesis (mg. kg(-1). day(-1)) increased by 40% in the air group (P = 0.068) and by 100% in the foot group (P < 0.001). Hypoxia and alkalosis at high altitude did not differ between the groups. Plasma interleukin-6 was increased modestly in both groups but C-reactive protein was not changed in either group. It is concluded that increases in PV and plasma protein synthesis at high altitude result mainly from the physical exercise associated with climbing. However, a small stimulation of albumin and fibrinogen synthesis may be attributable to hypobaric hypoxia alone.

Adult↗

[Recurrent Clostridium difficile enterocolitis].

Pseudomembranous enterocolitis generally occurs after antibiotic treatment. The standard treatment is oral metronidazol or vancomycin. Nevertheless, relapses of Clostridium difficile enterocolitis are observed in 10-25% of cases. Factors associated with recurrences include endogenous reinfection by spore formation, selective IgG1 or IgA deficiency or infection with mutated strains of Clostridium difficile. Recurrent Clostridium difficile enterocolitis may be treated with repeat oral vancomycin combined with Sacchoromyces boulardii, with intravenous immunoglobulin for severe colitis.

Aged↗

[Junk food revolution or the cola colonization].

In ancient times, the main problem was to get food. Nowadays the difficulty is to decide for or against some foodstuff. In industrialized countries, this abundance led to the fact that people eat differently from what they should. Traditional populations were subject to periods of feast and famine. Those with a metabolism which stored energy with high energetic efficiency had a survival advantage. This is called the 'thrifty' genotype hypothesis. With the secured supply of calories, coupled with a sedentary lifestyle, the thrifty genotype becomes disadvantageous, causing obesity. Industrialization or 'cola-colonization' also leads to a dramatic increase in obesity and non-insulin dependent diabetes mellitus in developing countries. The spread of fast food restaurants all over the world has changed modern nutrition fundamentally. Influence begins early in childhood. Advertising concentrates on the selling of image over substance. However, fast food contains high levels of fat, especially trans fatty acids. Higher consumption of trans fatty acids was associated with a higher incidence of and mortality from coronary heart disease.

Adult↗

[Obesity: principles of drug therapy].

Obesity is a major global public health problem. In many instances, a combination of diet modification, increased physical activity and behavior therapy fail or are insufficient for sustained weight loss. In these situations, drug therapy may be helpful. However, drug treatment of obesity resulted in unexpected devastating events in recent years. In the late sixties, aminorex caused an epidemic of pulmonary hypertension with high mortality rates. Dexfenfluramine and phentermine were also associated with the development of pulmonary hypertension and with alarming reports of cardiac valvular abnormalities. Therefore, these drugs were withdrawn from the market. Newer drugs, like sibutramine, a serotonin and norepinephrine reuptake inhibitor, and orlistat, a specific lipase inhibitor, reduce body weight significantly compared to placebo. In combination with a hypocaloric diet, weight loss of three to ten kilos can be achieved. Pharmacotherapy is limited to patients with a body mass index greater than 30 kg/m2, if non-pharmacological treatment programs have failed. The drugs should be prescribed under strict medical surveillance only.

Aminorex↗

[Rhabdomyolysis in carnitine palmitoyltransferase II deficiency: developments in pathophysiology, diagnosis and therapy].

In hospitalized patients rhabdomyolysis is an important clinical entity, leading to myoglobinuria and acute renal failure in 8-25% of cases. When common causes of rhabdomyolysis, such as crush, trauma, infections, and drug abuse are excluded, inherited disorders of energy metabolism, in particular lipid metabolism, should be considered. Carnitine palmitoyltransferase (CPT) II deficiency is a common disorder of mitochondrial lipid oxidation. There are two distinct clinical forms: a severe and usually fatal infantile form and a benign classical muscular form. Usually, patients with CPT II deficiency present with episodic myoglobinuria, muscle cramps and weakness prompted by strenuous exercise or prolonged fasting. Liver and cardiac dysfunction are rarely seen and indicate severe disease. Most affected patients are males, although CPT II deficiency shows an autosomal recessive mode of inheritance. The human CPT II gene has been cloned, sequenced and localised to chromosome 1p32. Several mutations have been detected in the human gene which differ in the remaining enzyme activity and may explain the heterogeneity in the clinical picture of this disorder. Diagnosis is by muscle biopsy. Normally, light microscopy shows no pathological findings, and diagnosis must be established by biochemical and molecular methods. In our report on two typical cases we set out to promote knowledge of this disorder and discuss the diagnostic approach, which requires a specialised laboratory.

Adult↗

[Clinical value of bilateral measuring of blood pressure].

By describing six patients who present with a multitude of clinical signs we want to demonstrate the importance of bilateral blood pressure readings. In patients with repeated blood pressure differences in the two arms of greater than 20 mmHg [1] further examination by ultrasound and/or angiography is indicated.

Adult↗

Immuno-nutrition: designer diets in cancer.

Weight loss, associated with advanced stage of neoplastic disease, is negatively correlated with survival in cancer patients. Alterations in substrate metabolism contribute to the impaired nutritional status. Energy expenditure, assessed by indirect calorimetry, seems to be very variable. Hypermetabolism may occur frequently, but the increase in energy expenditure rarely exceeds 10-15%. Another hallmark of cancer is depression of both cellular and humoral immune functions. Glutamine, the most abundant amino acid in the body, is an important substrate for rapidly proliferating cells and tissues. Arginine has been shown to stimulate the immune system, to enhance wound healing and to decrease the rate of tumour growth. Dietary supplementation with omega-3 fatty acids shifts the production of prostaglandins from the dienoic to the trienoic variety, which is much less immunosuppressive. Finally, administration of oligonucleotides improved survival to a challenge with Candida albicans. The needs for nutritional support in cancer patients should be considered from at least two perspectives: curative versus palliative treatment. Several prospective, randomized, double-blind studies in cancer patients undergoing major upper gastrointestinal surgery demonstrated significant improvements in postoperative immunological responses, a reduction in the frequency of infections and wound complications and in the length of hospital stay in the group receiving a diet enriched with arginine, RNA and omega-3 fatty acids. However, the impact on mortality remains to be established. In palliative situations, no clinical data documenting beneficial effects of long-term nutritional support with designer diets have been published, probably as a consequence of persisting concern about promoting tumour growth. Moreover, because of the heterogeneity of this patient population such studies are difficult to perform. Finally, nutritional intervention for patients with terminal cancer remains highly controversial. The basis for improvements in nutritional support is a better understanding of the metabolism of cancer patients, especially in patients with advanced disease.

Clinical Trials as Topic↗

Immunohistochemical demonstration of interleukin-1 beta induced changes in acute-phase proteins and albumin in rat liver.

Interleukin-1 beta is a potent mediator of the acute-phase response. However, the effects of interleukin-1 beta administration on the topic in vivo production of acute-phase proteins and albumin are so far not well understood. Overnight fasted rats were subcutaneously injected with 0.2 mL 0.9% NaCl (control group) or 6.25 micrograms recombinant human interleukin-1 beta, and rectal temperature was measured at intervals up to 48 h. Livers were perfused-fixed in vivo prior to injection (base-line), and at 9, 24, and 48 h following the interleukin-1 beta injection. Fibrinogen, orosomucoid (alpha 1-acid glycoprotein) and albumin were immunostained using a streptavidin-biotin-immunoperoxidase technique. Rectal temperature peaked 5 h after the single interleukin-1 beta injection, and fell gradually to base-line values by 24 h. Prior to injection only a few hepatocytes, randomly scattered throughout the liver lobule, stained positive for fibrinogen and orosomucoid. In contrast, all hepatocytes stained uniformly positive for fibrinogen and orosomucoid 9 h after interleukin-1 beta injection, whereas at 24 h a predominant centrilobular staining pattern occurred. Due to fasting, albumin positive hepatocytes were already reduced at base-line in both groups. Interleukin-1 beta induced a further significant loss of albumin positive cells in the periportal zone (35 +/- 21%) at 9 h when compared with controls (58 +/- 11%, p = 0.037). In conclusion, subcutaneous interleukin-1 beta (probably by stimulation of interleukin-6) strongly induces fibrinogen and orosomucoid expression in rat liver, and suppresses immunohistochemically stainable albumin in a heterogenous way, mainly in the periportal zone.

Acute-Phase Proteins↗