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Biomedical subjects

U Jensen

Publications and source records attributed to U Jensen.

At least 19 recordsLinked to original sources
PubMed2000

The calculation of blood ethanol concentrations in males and females.

In German-speaking countries, blood ethanol concentrations (BECs) are usually calculated using Widmark's equation. The distribution factor r of this equation is a correction factor needed to obtain a reduced body mass and corresponds to the ratio of total body water and blood water content. To enhance the reliability of Widmark's model equation, the body weight, body height, blood water content and total body water of 256 women and 273 men were measured. The ratio of body water to blood water ranged from 0.44 to 0.80 in women and from 0.60 to 0.87 in men. For both sexes equations were developed by multiple regression analysis which allow the determination of the individual, more realistic distribution factors rFI (for females) and rMI (for males) even when only body height and body weight are known. Drinking experiments revealed a clearly higher congruence of calculated and measured blood ethanol concentrations when rFI or rMI were used instead of rigid distribution factors, i.e. 0.6 for women and 0.7 for men with or without the assumption of a 10% so-called resorption deficit. Additionally, Widmark's equation in combination with rFI or rMI allows a more accurate prediction of blood ethanol concentrations than the equations of Watson and Ulrich.

Adult↗
PubMed2000

Neurologic injury in cardiac surgery: aortic atherosclerosis emerges as the single most important risk factor.

With older and sicker patients undergoing cardiac surgery, neurologic injury has emerged as an increasingly important cause of rising costs, morbidity and mortality. Several studies investigating the relationship between atherosclerotic aortic disease and subsequent adverse clinical outcomes have demonstrated that the single most important risk factor for neurologic injury following cardiac surgery is the presence of aortic atheromatous disease. The results of these studies suggest that atheroemboli are correlated with neurologic injury following cardiac surgery. Surgical techniques to avoid and prevent particulate debris during cardiac surgery may be a major step in preventing severe neurologic injury.

Aortic Diseases↗
PubMed1995

Characterization and evolutionary relationships of Magnolia legumin-encoding cDNAs representing two divergent gene subfamilies.

We have cloned and sequenced three different cDNAs encoding legumins of Magnolia salicifolia. Analysis of the nucleotide and derived amino acid sequences shows that the cDNAs designated A2, A11, and B14 represent two divergent subfamilies with nucleotide similarities of only about 55%. The B14 cDNA codes for a relatively methionine-rich legumin precursor, and the beta-chain of this protein is shown to be glycosylated; neither feature is common in legumin. In an evolutionary analysis, the B14 legumin cDNA is relatively similar to gymnospermous legumin sequences and paralogous to all angiosperm legumins hitherto known. The A legumin sequence clusters with those of monocot legumins in a low angiosperm branch. We conclude that the evolution of legumin genes in angiosperms involved an early gene duplication which resulted in the progenitor of the B14 legumin, on the one hand, and the progenitor of A2, A11 and modern angiosperm legumins, on the other hand.

Amino Acid Sequence↗
PubMed1994

Increase of streptozocin toxicity by magnesium deficiency in the diabetic rat model.

To study interactions between magnesium (Mg) and diabetes mellitus, female SD-rats weighing ca. 230 g were rendered Mg-deficient by offering a diet providing only 20% of the rat's requirement. After 14 days the animals were injected 75 mg streptozocin (STZ) per kg body weight intraperitoneally. Placebo-treated controls received the same diet, however their drinking-water was enriched with 20 mmol/l Mg as the magnesium-L-aspartate hydrochloride. Mg deficiency remarkably increased STZ-induced lethality from 3.8% to 61.1% on day 35. Pronounced hyperglycemia and necrosis of pancreatic beta cells also suggest an increased effect of STZ on the pancreas during Mg deficiency. The underlying mechanisms are discussed. Food consumption was decreased in Mg-deficient animals and steeply increased 7 days following STZ treatment. Similarly consumption of drinking-water also increased. Since diabetic rats lost body weight, relative and absolute Mg intake via food or drinking-water increased. In this way further Mg depletion of diabetic rats was prevented.

Animals↗
PubMed1993

Prevention of cerebral ischaemia under general anaesthesia.

General anaesthesia influences the oxygen supply/demand ratio of the brain and may thus be able to improve neurological outcome after carotid artery surgery. Among the anaesthetic agents, barbiturates and isoflurane produce a marked reduction of the cerebral metabolic rate and activity. But the incidence of neurological deficits in the immediate postoperative period is low, while the possible causes of any neurological deficits are multiple. Consequently, to date, no particular anaesthetic agent or management has been shown to influence the neurological results.

Analgesics, Opioid↗
PubMed1993

[Ambulatory epidural morphine analgesia via a transcutaneous implanted spinal catheter].

This report deals with a patient suffering from recurring rectum carcinoma infiltrating the lumbosacral plexus who received ambulant treatment with spinal opiate supply by a pump device, using a transcutaneous spinal catheter over a period of 12 weeks. The catheter turned out to be simple to implant. During the whole period no malfunctions occurred. This form of spinal analgesic treatment allowed the patient a relatively pain-free life outside the hospital.

Ambulatory Care↗
PubMed1992

The N-terminal amino acid sequence of the beta-subunit of the legumin-like protein from seeds of Ginkgo biloba.

The sequence of the first 52 amino acids at the N-terminus of the beta-subunit of a legumin-like protein from seeds of the gymnosperm Ginkgo biloba were determined by automated sequencing and DABITC/PITC microsequence analyses of peptides derived from the protein by enzymatic digestions and chemical cleavage with CNBr. The protein from Ginkgo exhibits sequence homologies (32-49% identities) with the 11S globulins and legume-like proteins from seeds of various angiosperm monocotyledons and dicotyledons.

Amino Acid Sequence↗
PubMed1988

[The equilibrium of nitrogen, potassium and phosphate and renal excretion of creatinine and creatinine over the course of 3 weeks following severe trauma].

In 19 patients after accidental trauma and with intact renal function during an observation time of 21 days we found a cumulated negative balance of nitrogen (N), phosphate (P) and potassium (K) amounting to a mean of 214g, 357 and 447 mmol, respectively. Median daily potassium balance was positive on day 2 to 5 and this was interpreted as an increased extrarenal potassium deposition due to increased levels of circulating catecholamines. Median renal creatinine excretion was about 120% of predicted normal till day 10 and continuously decreased thereafter to values lower than predicted normal. Three patients did not show creatinuria (greater than 200 mg/day) during the whole observation time. In 15 patients after a "free interval" with a mean duration of 7 days creatinuria frequently developed rather quickly and maximal excretion of creatine was as high as 4 g/day. In 7 patients creatinuria persisted to the end of the 21 days observation time. During the phase of creatinuria the median cumulated excretion of creatine amounted to 14.4 g. The "free interval" of creatinuria after severe trauma is remarkable. Most of the N, K and P, which is lost from the body during this time obviously stems from tissues other than sceletal muscle. During the phase of creatinuria, however, the negative balance of N, K and P seems to be mainly due to muscle wasting. Hypophosphatemia was prominent during the first 5 days after trauma and obviously was caused by a decrease in renal phosphate threshold (TmPO4/GFR). The underlying mechanism of this primary change in renal function after severe trauma could not yet be identified.

Adolescent↗
PubMed1988

[Water-electrolyte balance and kidney function for 3 weeks following severe trauma].

A study on water-electrolyte metabolism and renal function was performed in 32 patients (mainly young to middle-aged males) over three weeks after severe accidental trauma (mainly brain trauma), who did not suffer from acute renal failure. With a mean water input of 4 l/day the difference of water input and urine volume was positive over the whole observation time. Patients had a mean osmolar excretion of 1800 mosm/day which was twice normal and was mainly caused by a high urea excretion. They were almost invariably in the state of antidiuresis and achieved unusually high values for negative free-water clearance around 2 ml/min. This, however, was adequate in terms of normotonicity of body water. Cumulated sodium balance over 21 days was negative and, on the average, amounted to minus 440 mmol. The median value for creatinine clearance was in the range of predicted normal (156 ml/min.) between day 5 and 10 and a little less before and thereafter. We frequently observed an elevation of creatinine clearance to 120-150% of normal. Renal clearance of urea was around 100 ml/min. during the phase of maximal protein catabolism. Therefore the reasonable increases in urea production up to a mean of 60 g/day resulted only in moderately elevated levels of plasma urea (40-50 mg/100 ml). In 14 patients we performed a total of 83 measurements of plasma volume (Evans-Blue). In patients with intact renal function mean plasma volume amounted to 110% normal. This, in combination with a reduced red all volume on the average, resulted in mild hypovolaemia (blood volume about 90% of predicted normal).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1987

Prevention of colonization and respiratory infections in long-term ventilated patients by local antimicrobial prophylaxis.

In a randomized clinical trial the prophylactic effects of locally administered antimicrobials on quantitative colonization and respiratory infections were studied in intubated patients with an expected period of mechanical ventilation of greater than 6 days. Nineteen patients received 50 mg of polymyxin B and 80 mg of gentamicin distributed among nose, oropharynx and stomach at 6-h intervals, as well as 300 mg of amphotericin B in the oropharynx. Twenty untreated patients served as controls. In the control group colonization by respiratory pathogens was more common (oropharynx 19 vs 6 patients (p less than 0.001); trachea 19 vs 11 (p less than 0.01)), and the number as well as the count of the colonizing species was usually higher. Fourteen patients of the control group developed respiratory infections, including nine cases of pneumonia, as compared to four patients with prophylaxis, including one case of pneumonia (p less than 0.01). Pneumonia-associated deaths were prevented with prophylaxis; however, the overall mortality remained unchanged. Respiratory infections in the prophylaxis group were associated with organisms resistant to the agents used, but the overall occurrence of resistance was not increased, as compared to the control group. We conclude that unrestrained upper airway colonization by respiratory pathogens and respiratory tract infection were causally related. Local antimicrobial prophylaxis proved to be a highly effective strategy for the prevention of potentially life-threatening pneumonias in critically ill patients, but in the present study the host setting appeared to be the major determinant of outcome.

Administration, Intranasal↗
PubMed1986

[Work of breathing in spontaneous respiration with continuous positive airway pressure].

In postoperative respiratory failure continuous positive airway pressure (CPAP), besides improving pulmonary gas exchange, influences respiratory mechanics. Elastic and flowresistive components of respiratory work were measured in intensive care patients being weaned from the respirator. Measured values during breathing with a continuous-flow CPAP system with elastic reservoir were compared with those for O2 breathing via T-tube. Under CPAP total breathing work and resistance were reduced. Compliance, tidal volume and respiratory frequency did not change significantly. The reduction in respiratory work was primarily due to decreased nonelastic work associated with a decrease in resistance. Thus, on weaning from mechanical ventilation using a reservoir-CPAP system, the respiratory work was reduced in comparison to O2 breathing via T-tube.

Airway Resistance↗
PubMed1986

[Thiopental kinetics in high-dose use].

The kinetics of thiopentone when administered in high doses were investigated in two patients with elevated intracranial pressure and three patients with focal cerebral ischemia. Initial saturation of the tissues is best achieved by a series of infusions with decreasing infusion rate. Administration of a bolus followed by maintenance doses proved unsuitable. The course of concentration under maintenance dosage was extremely variable, mainly due to interindividual and intraindividual variations in clearance. The apparent distribution volumes in these patients (1.38-3.10 l/kg, mean 2.43 l/kg) corresponded to the volumes determined after bolus administration. The total body clearance was low (45.8-103.4 ml/min, mean 72.3 ml/min) and was the reason for long elimination half-times (15.6-25.0 h, mean 23.2 h). Four patients biotransformed thiopentone regardless of the concentration. In one female patient the biotransforming enzyme systems may have been saturated. While conversion of thiopentone to pentobarbitone is generally only of secondary importance, an unusually high plasma pentobarbitone concentration was observed in one patient, reaching 50% of the concentration of the original substance. On the average, thiopentone was 75-80% proteinbound. The binding rate changed considerably with time. It could not be shown that this was influenced by albumin concentration between 25 and 50 g/l. The thiopentone concentration in the ventricular fluid corresponded approximately to that in the plasma fluid. Owing to the variability of the total body clearance and plasma protein binding, and the possibility of changes in tolerance, thiopentone administration must be controlled individually according to the EEG and intracranial pressure. Monitoring of the drug concentration in plasma is recommended.

Adult↗
PubMed1983

Metabolism of phosphate and calcium after severe accidental trauma.

Hypophosphatemia is a common finding during the first 4-5 days after severe accidental trauma. We demonstrated that hypophosphatemia after trauma is caused by a definite decrease in renal phosphate threshold (TmPO4/GFR), that is the theoretical plasma phosphate concentration at which all of the filtered phosphate is reabsorbed by the renal tubules and renal excretion of phosphate is close to zero. We speculated that the decrease in renal phosphate threshold could be due to an increased activity of PTH which in turn could be the result of ionized hypocalcemia. In 7 patients with severe and in 8 patients with moderate trauma, however, we found ionized calcium and PTH levels to be within normal limits. Total plasma calcium was below normal (1.90-2.00 mmol/l) up to 20 days after trauma, probably due to a decreased plasma albumin concentration (25-30 g/l). We conclude, that ionized hypocalcemia and consecutive stimulation of PTH is not the cause of decreased renal phosphate threshold after severe accidental trauma.

Adolescent↗