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Biomedical subjects

B Drews

Publications and source records attributed to B Drews.

At least 19 recordsLinked to original sources
PubMed2001

Cerebrospinal fluid response to structured treatment interruption after virological failure.

OBJECTIVE: Structured antiretroviral treatment interruption (STI) has been advocated as a therapeutic strategy for HIV-1 infection. We report initial observations of cerebrospinal fluid (CSF) HIV-1 infection in five patients undergoing serial lumbar punctures (LPs) during STI undertaken following virological failure. DESIGN AND METHODS: In this prospective observational study we quantified HIV-1 RNA concentrations and assessed both phenotypic drug susceptibility profiles and genotypic antiviral drug resistance mutations in CSF and plasma during the period of treatment interruption. CSF white blood cells were also counted, and patients' neurological status monitored. RESULTS: In four of the patients, CSF HIV-1 concentration increased more rapidly than that of the plasma, with consequent reduction in the ratio between plasma and CSF viral loads (pVL : cVL). Three individuals developed robust, though asymptomatic CSF lymphocytic pleocytosis. In all patients the predominant HIV-1 quasispecies shifted simultaneously in CSF and plasma from a drug-resistant to a more drug-susceptible phenotype with identical and simultaneous changes in genotypes associated with drug resistance. CONCLUSIONS: STI may be accompanied by previously unrecognized changes in tissue viral exposures and lymphocyte traffic. Hence, despite 'virological failure' as evidenced by persistent plasma viremia, ongoing antiretroviral treatment prior to its interruption appeared to suppress CSF HIV-1 infection (indeed more effectively than that of plasma) and restrain lymphocyte traffic into the CSF. Simultaneous change of resistance mutations in CSF and plasma was likely due to re-emergence and overgrowth of pre-existing strains with ready exchange of virus between these two compartments, either facilitated by or provoking a local CSF lymphocytosis.

Adult↗
PubMed1998

Venous Function in Patients with Venous Disease and Healthy Controls Before and After a Bathing Procedure and Subsequent Cold Stimulus

The object of this study was to determine whether bathing in thermal water acutely affects venous function in patients with venous insufficiency. Measurements were taken of venous function in patients with leg varicosities and healthy subjects before and after a thermal bath and exercise on two days, with subsequent application of a cold stimulus on 1 day. A total of 28 patients with varicose veins in one or both legs (n = 45 legs) and 30 healthy controls (n = 60 legs). On 2 consecutive days all subjects underwent a standardized bathing and exercise procedure in water at 34 degreesC for 20 minutes. On one day, determined randomly for each subject, a cold stimulus was applied to both lower legs after bathing. Measurements were done before subjects entered the bath and after the completion of bathing (including cold stimulus on one day). Without the cold stimulus, venous function of patients and controls did not change. After application of the cold stimulus the venous capacity of both patients and controls was significantly reduced compared with the basal levels. There was no change in maximum venous outflow in the controls, but that of the patient group decreased slightly compared with basal levels. Contrary to widespread belief, bathing in water at temperatures above 28 degreesC does not adversely affect venous function in patients with varicose veins. When applied in moderation (34 degreesC for 20 minutes) this physical therapy should not be regarded as contraindicated in this and related conditions, especially given its known hemodynamic benefits. Further studies are required to determine the long-term effects of repeated immersion.

Journal Article↗
PubMed1997

Physical therapy improves venous hemodynamics in cases of primary varicosity: results of a controlled study.

Physical factors are known to influence hemodynamics in the veins of the lower extremities. In a controlled, randomized study the authors investigated the effects of combined physical therapy on varicose veins. Over a twenty-four-week period a treatment group consisting of 12 persons exercised under the supervision of a therapist twice a week for sixty minutes. This included muscle and joint activation by means of externally applied compression and cold-temperature stimuli (ie, thermosteresis). They also exercised once a day without supervision for fifteen minutes. During the same period a control group of 12 persons underwent the same measurements but no treatment. In the treatment group venous capacity decreased by an average of 16% from 4.9 +/- 0.3 (sd) mL/100 mL tissue to 4.1 +/- 0.4 (P < 0.005, U-test) while in the control group it remained practically unchanged at 4.8 +/- 0.4 vs 5.0 +/- 0.3. Venous refilling time in the lower extremities also increased in the treatment group, half refilling time rising from 7.8 +/- 1.0 to 11.3 +/- 0.9 seconds (P < 0.001) and total refilling time from 17.0 +/- 1.4 to 25.7 +/- 2.1 seconds (P < 0.001); these parameters remained virtually unchanged in the control group, with half refilling time dropping slightly from 7.7 +/- 1.1 to 7.1 +/- 1.3 seconds and total refilling time from 18.3 +/- 1.7 to 16.3 +/- 1.9 seconds. Patient self-rating scores obtained by use of a standardized questionnaire administered at baseline and at the end of week 24 improved in the treatment group only. The combined physical therapy was thus shown to be of long-term therapeutic value, improving venous function and reducing patients' symptoms. These findings indicate that for the further development of this combined treatment regimen it would be useful to identify the individual factors contributing to its efficacy and evaluate them separately.

Adult↗
PubMed1995

Efficacy, safety, and cost of intravenous sedation versus general anesthesia in children undergoing endoscopic procedures.

We prospectively evaluated 226 patients under 18 years of age who underwent 296 procedures, and intravenous sedation and general anesthesia were compared in regard to efficacy, safety, and cost. Children 6 to 9 years of age required the highest doses of midazolam (0.14 +/- 0.04 mg/kg) and meperidine (2.5 +/- 0.8 mg/kg). A Relative Adequacy Scale, constructed to assess each patient's arousal and cooperation during intravenous sedation, revealed a 95% completion rate. Heart rate monitored before, during, and after the procedure was similar in both groups during the procedure, but a lower preprocedure heart rate was noted in older patients having intravenous sedation, suggesting less patient anxiety. Average charges, excluding endoscopist's and pathology fees, were $768.52 in the intravenous sedation group versus $1,965.42 in the general anesthesia group. Endoscopic procedures can be performed safely, effectively, and at a lower cost to the patient under intravenous sedation in a properly equipped and staffed pediatric endoscopy suite.

Adolescent↗
PubMed1991

[CO2-induced acral blood flow and the oxygen partial pressure in arterial occlusive disease].

The effect of CO2-containing water on foot skin blood flow (laser-Doppler flux) and transcutaneous oxygen partial pressure (tcpO2) was measured in 16 patients (15 men and 1 woman; mean age 58 [49-71] years) with peripheral arterial occlusive disease (stage II of Fontaine: bilateral occlusions of the superficial femoral arteries). After 30 minutes lying down and 10 minutes sitting up, one lower leg was immersed in fresh water, the other in CO2-containing water (1400 mg CO2/kg H2O), both at 34 degrees C for 20 minutes. On the next day the measurements were repeated changing sides. Skin blood flow of the dorsum of the foot and rhythmic flow oscillations (flux motion) increased threefold in the CO2 water-bath, after a latency period averaging 2 minutes, within 3 minutes from 1.1 to 3.9 relative units (P less than 0.005). Average tcpO2 increased during the bath in CO2 water by 9 mm Hg (P less than 0.005). There was no change in fresh water. The increase in cutaneous blood flow and oxygen partial pressure, which persisted throughout the period in CO2 water, is interpreted as an increase in microcirculation and can explain part of the effectiveness of this largely empirical treatment.

Aged↗
PubMed1991

[Increase in skin blood circulation and transcutaneous oxygen partial pressure of the top of the foot in lower leg immersion in water containing carbon dioxide in patients with arterial occlusive disease. Results of a controlled study compared with fresh water].

Semi-quantitative Doppler laser flowmetry and measurement of transcutaneous oxygen partial pressure (TCPO2 in mmHg) are reliable, non-invasive methods of continuous measurement suitable for underwater use. We measured the effect of aqueous CO2 (succinate + sodium bicarbonate = Kao Bub; 1400 mg CO2 per kg water) compared with fresh water (both at 34 degrees C, depth of leg immersion 35 cm, immersion time 20 min) on circulation and TCPO2 in the feet of 15 patients with bilateral stage-II occlusion of the Aa. fem. superf. intraindividually in a randomised, crossover trial. Measurements were made at the same time of day on two consecutive days. No change in either cutaneous microcirculation or TCPO2 was observed during immersion in fresh water. During immersion in a CO2 bath both culaneous blood flow (as expressed by Doppler laser flux) and the amplitude of the Doppler laser vasomotion flux increased more than threefold (p less than 0.001, Wilcoxon), while sitting TCPO2 increased by over 10% (from 63 to 71 mmHg; p less than 0.001). The observed changes in oxygen dissociation and cutaneous microcirculation may help to provide an explanation for the well-known therapeutic effect of CO2 baths in all stages of occlusive arterial disease.

Adult↗
PubMed1988

Plasma-triglycerides and exercise: a delicate balance.

Alimentary lipemia was studied in 12 healthy young men with and without exercise. Three sets of experiments were performed. While continuous exercise of 90 min duration significantly reduced postprandial triglycerides by 26% (study I), this effect could not be observed when exercise was interrupted for 5 min after each 25 min (study II). Plasma free fatty acid concentrations, in the latter experiment, were significantly higher (by 311%) than during rest. When, in a third experiment continuous exercise was compared with intermittent physical activity, the latter condition significantly increased postprandial triglyceridemia, most probably due to precipitous rises of free fatty acids on each interruption of ergometry. It is concluded that in the third experiment the balance between triglyceride removal and triglyceride synthesis was shifted toward the latter. Whether exercise lowers, leaves unaltered, or raises plasma triglyceride levels may depend on subtle changes of experimental design.

Adult↗