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Biomedical subjects

B Hiller

Publications and source records attributed to B Hiller.

7 recordsLinked to original sources
PubMed1999

Pharmacokinetics and pharmacodynamics of hydroxyethyl starch in hypovolemic pigs; a comparison of peripheral and intraosseous infusion.

Intraosseous (i.o.) infusion is considered a useful technique for the administration of medications and fluids in emergency situations when peripheral intravascular access is not possible. This study investigated the effectiveness of i.o. versus intravenous (i.v.) infusion of hydroxyethyl starch (HES 200/0.5) in hypovolemic pigs. Twenty-three pigs (8- to 9-week-old) were anaesthesized, instrumented and blood was withdrawn (25-30 ml/kg) to < 50 mmHg mean arterial pressure (MAP). The animals were left untreated in haemorrhage for 30 min. Relevant haemodynamic parameters were monitored and blood samples were collected for blood gas and HES concentration analysis. Infusion of HES via i.v. or i.o. line (20 ml/kg per h) carried out over a period of 30 min for volume resuscitation and measurements were taken every 5 min. Infusion was discontinued after 30 min and the animals were monitored for 1 h. Analysis of HES-pharmacokinetics and pharmacodynamics revealed no significant differences between i.o. and the i.v. administration. The results demonstrate i.o. infusion of HES to be a rapid and effective method for fluid resuscitation in hypovolemic shock.

Animals↗
PubMed1998

The hydrostatic measurement of systolic toe blood pressure: a preliminary validation of the method.

BACKGROUND: The hydrostatic method of measuring systolic toe blood pressure has not been validated. A comparison with established non-invasive methods is presented. PATIENTS AND METHODS: Conventional sphygmomanometry was applied to assess systolic arterial pressure at the ankle and brachial level; systolic arterial toe pressure was assessed by the hydrostatic method. An 8 MHz Doppler probe was used to demonstrate arterial pulsation in brachial, ankle, and toe arteries, respectively. 50 legs of patients with peripheral arterial occlusive disease were studied before and after successful arterial revascularisation. RESULTS: In all legs, ankle pressure and ankle/brachial pressure index (ABPI) increased postoperatively. Hydrostatic toe blood pressure (HSTBP) increased in 96% of cases, in 58% of cases above the upper detection limit of 70 mmHg. HSTBP and sphygmomanometric ankle pressures were significantly correlated (r = 0.754, p < 0.05). CONCLUSION: Successful arterial revascularisation in legs with peripheral arterial occlusive disease was associated with an increase in systolic ankle pressure and ABPI, assessed with sphygmomanometry. Similar changes were observed in systolic toe arterial pressure, assessed with the hydrostatic method. The correlation of the results obtained with both methods can be taken as a preliminary indication of the accuracy of the hydrostatic method, which may be particularly useful in cases of medial arterial calcification.

Adult↗
PubMed1997

Quasispecies analysis in hepatitis C virus infection by fluorescent single strand conformation polymorphism.

Hepatitis C virus (HCV) results frequently in chronic hepatitis and its sequelae liver cirrhosis and hepatocellular carcinoma. Interferon-alpha is at present the most effective treatment, resulting in a sustained response in about 20-25% of patients. HCV genotype, titer and quasispecies determine the success of treatment. In this study, fluorescent single strand conformation polymorphism (f-SSCP) was evaluated for the analysis of HCV quasispecies. Two sera from a chronically HCV-infected patient, obtained 6 years apart, were examined. The hypervariable region I (HVRI) of the HCV genome was amplified by reverse transcription and PCR. The PCR products were cloned and sequenced or fluorescein-labeled and subjected to f-SSCP. Both methods demonstrated a single HCV species in the early serum and multiple quasispecies in the late serum. Single clones of the heterogeneous virus population were used to optimize conditions for f-SSCP. The most important factors were the gel temperature and virus titer. At the optimal running temperature one base exchange in 218 bases was detectable. Repeat extractions and amplifications gave identical results. Dilution of the serum containing multiple quasispecies resulted in a 'loss' of species. Provided the running temperature is optimal and virus titer is sufficient, f-SSCP is shown to be fast and reliable for HCV quasispecies analysis.

Amino Acid Sequence↗
PubMed1994

Tn 5Map, a transposon for the rapid mapping of restriction sites in plasmids.

A transposon was constructed allowing the rapid restriction mapping of plasmids. This transposon, Tn 5Map, contains a cleavage site for the I-SceI endonuclease which recognizes an 18-mer. After in vivo transposition of Tn5Map into the plasmid of interest, the plasmid is isolated and linearized with I-SceI. Splinkers labelled with digoxygenin and complementary to the left and right end of the linearized molecule are added and ligated. After partial digestion of the splinkered molecules with the restriction enzyme of interest, separation of the cleavage products in an agarose gel, and Southern transfer, the labelled fragments are visualized by the addition of the chemiluminescent substrate AMPPD and alkaline phosphatase. The restriction map can be directly read from the bottom to the top of the gel.

Bacteriocin Plasmids↗
PubMed1994

[A respiratory microvalve for spontaneously breathing anesthetized small animals].

For the accurate functional analysis of the gas exchange in the lungs or evaluation of artificial oxygen carriers in spontaneously breathing anaesthetized small animals, we developed a new respiratory micro-valve. The body of the valve is made of aluminium, and the flaps are made of silicone rubber. The maximum flow rate in a rat measured with a pneumotachograph and the micro-valve was an average of 19.9 ml/s during inspiration, and 17.8 ml/s during expiration. The pressure measured in the tracheal tube was -0.85 during inspiration, and +0.39 cm H2O during expiration; the end-expiratory pressure in the tube was zero. In two experiments with anaesthetised rats lasting 4-5 hours, ventilation, oxygen uptake, carbon dioxide release and the respiratory exchange ratio were 638 ml/min/kg, 21.7 ml O2(STPD)/min/kg, 16.6 ml CO2(STPD)/min/kg, and 0.77, respectively. There was no significant change in any parameter during the experiment. The micro-valve increases the dead space by approximately 35%, but this is well tolerated by the rats, which compensate by increasing their tidal volume by about 10 to 15%. The major advantage of using the micro-valve in comparison with other methods is the fact that the true difference between inspiratory and mean mixed expiratory gas can be measured with great accuracy. The micro-valve can readily be adjusted for optimal use with a range of animals.

Anesthesia, General↗