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Biomedical subjects

A Dittmar

Publications and source records attributed to A Dittmar.

At least 55 records · Page 3Linked to original sources
PubMed1990

Influence of computer-modulated profile haemodialysis on cardiac arrhythmias.

To reduce hamodialysis-induced ventricular arrhythmias, each of 15 patients (age 66.9 +/- 6.2 years) with end-stage renal disease and cardiac irregularities was treated subsequently with four different computer-modulated bicarbonate haemodialysis profiles (A-D) for 2 weeks respectively: (A) constant UF, dialysate Na (138 mmol/l) and K (2 mmol/l); (B) decreasing UF, otherwise as (A); (C) decreasing UF and Na (starting with 10% higher than serum Na), otherwise as (A); (D) decreasing UF and Na, adapted K to achieve a maximal reduction of serum K of only 15%/h. Cardiac monitoring was done by 11 h ECG. Only in haemodialysis profile D a distinct reduction of ventricular extrasystoles during and after haemodialysis was obtained. It was accompanied by an improvement in the Lown classification. In addition, a weak but highly predictive correlation between the number of ventricular extrasystoles in the last hour of dialysis and the difference between pre- and post-dialysis potassium concentration in the serum could be established (r = 0.37; P less than 0.004). Computer-modulated potassium profile haemodialysis is a useful tool to reduce the number and severity of ventricular extrasystoles.

Aged↗
PubMed1990

[A comparison of intermittent compression with single and multi-chamber systems in treatment of secondary arm lymphedema following mastectomy].

In a comparative study 38 patients with secondary unilateral lymphatic oedema after mastectomy were investigated with regard to the efficacy of intermittent compression treatment using uni- or multichamber systems (Jobst and Lymph-a-mat respectively). Although both machines significantly reduce oedema, there is no difference between their reduction capacities.

Arm↗
PubMed1988

[Hypothermia and paradoxical sleep. I. Pontile cats without hypothalamo-hypophysis].

Chronic pontile cats (without hypothalamo-hypophysis) were kept during 4 days at central T (TC) between 37.5 and 30.8 degrees C at stable ambiant T (TA) between 28.5 and 23 degrees C. The vasomotor index of the forepaw was chosen for studying change in vasomotricity. Small and slow variations of TA (+1.5 degrees C) around 27 degrees C were followed by thermoregulatory response since a progressive decrease of TA under 27 degrees C led to vasoconstriction and increase of TC while progressive increase of TA above 27 degrees C led to vasodilatation and decrease of TC. However rapid and large decrease of TA under 27 degrees C (24-23 degrees C) led to the expected hypothermia with decrease of TC but without vasoconstriction. Paradoxical sleep (PS) amounts were strongly correlated with TC. At TC above 35.5 degrees C PS was almost totally suppressed while it increased significantly under 35 degrees C (Q10 = 0.10). Under 35 degrees C at stable TC and TA, PS occurred with an endogenous circahoral rhythm which did not vary significantly between 35 and 32 degrees C. These results strongly suggest that in pontile cats, PS is both gated and regulated by TC, while TC is regulated by pontobulbar vasomotor systems in response to TA. The putative role of the ventro-lateral medulla, in controlling both vasomotricity, TC and the excitability of the locus coeruleus is discussed in relation with PS.

Animals↗
PubMed1987

[Surface analysis of Bio-Sinter ceramic specimens using Rutherford backscattering spectrometry following subcutaneous implantation].

The formation of a calcium and phosphorous containing surface-layer is one of the essential suppositions of bioactive materials for the replace of bone. In the submitted study on sintered Bio-Vitro-ceramic specimens, which where explanted from the subcutaneous tissues of rats after 20, 40, 90 and 180 days, a relative increase of calcium content, and an absolute increase of phosphorous content of the direct surface of the specimens (approximately 0.01 micron) could be demonstrated. In contrast to not implanted specimens the values of silicat were 90% lower. After 180 days of implantation the distribution of elements at the surface of all types of sintered specimens had been stabilized 1.6 (Ap40KS15), 7.1 (Ap40KS30), 2.3 (Ap40SV).

Animals↗
PubMed1986

Skin blood flow changes in anaesthetized humans: comparison between skin thermal clearance and finger pulse amplitude measurement.

The effect of general anaesthesia on skin blood flow in the left hand, measured by a new non-invasive probe using the thermal clearance method was examined. A mercury silastic gauge was placed around the third left finger and the plethysmographic wave amplitude was recorded to measure changes in finger pulse amplitude. Heart rate (HR), mean arterial blood pressure (MABP) and skin temperature were also recorded. General anaesthesia was induced by droperidol and phenoperidine injection and propanidid infusion in eight female patients. Skin thermal clearance, plethysmographic wave amplitude, HR, MABP and skin temperature were 0.40 +/- 0.02 w X m-1 degree C-1, 9 +/- 1 mm, 98 +/- 5 beats X min-1, 12.50 +/- 0.93 kPa and 33.3 +/- 3.4 degrees C respectively. The minimal value of MABP was 9.58 +/- 1.06 kPa, whereas skin thermal clearance, plethysmographic wave amplitude, HR and skin temperature increased to 0.45 +/- 0.02 w X m-1 degree C-1, 29 +/- 3 mm, 110 +/- 4 beats X min-1 and 34.4 +/- 0.4 degrees C. Changes in skin thermal clearance correlated well with plethysmographic wave amplitude. Statistically significant changes in these two parameters occurred before significant change in HR, MABP or skin temperature. The results show that the new non-invasive probe using the thermal clearance method appears to be a useful device for measuring cutaneous microcirculation in anaesthetized humans, and responds more quickly than change in skin temperature, which is a delayed effect of skin blood flow change. Our results also show that the intensity of cutaneous vasodilatation induced by general anaesthesia did not relate to the vascular tone before anaesthesia.

Adult↗
PubMed1986

Changes in skin thermal clearance during anaesthesia.

Thermal and vascular side effects occurring during general anaesthesia are related to skin blood flow. A new, noninvasive probe which measures skin thermal clearance, a variable closely related to skin blood flow, was used in nine patients under phenoperidine, droperidol, propanidid anaesthesia. Statistically significant increases in skin thermal clearance clearly preceded the drop in mean arterial blood pressure and the rise in skin temperature. It is concluded that general anaesthesia induced an early increase in skin blood flow and that thermal clearance is a better technique than skin thermometry to monitor skin blood flow.

Adult↗
PubMed1986

Relationship between pulse amplitude and thermal exchange in the finger: the effect of smoking.

In 24 healthy volunteers finger pulse amplitude and heart rate (HR) were monitored by pulse plethysmography and thermal exchange from the finger and were compared before and after the smoking of a single cigarette. Thermal exchange was measured using a direct calorimeter consisting of a recording bath and a reference bath, both of which were filled with water at 18 degree C. The subject immersed the two distal phalanx of a finger into the recording bath. The water thermal gradient between both baths after 4 min of finger immersion and the maximal value of heat loss from the finger to the water were recorded. Decreases in the water thermal gradient (from 6.06 to 5.33 degrees C, P less than 0.05) in maximal value of heat loss (from 22.5 to 18.75 w.m-2, P less than 0.01) and in plethysmographic wave amplitude (from 25.8 to 14.6 mm, P less than 0.01) and increased HR (from 72 to 83 beats min-1) were observed in smokers. These changes were not statistically significant in non-smokers. Water thermal gradient and maximal value of heat loss correlated with plethysmographic wave amplitude before and after smoking but not with HR in the 24 subjects studied. The present study shows a good relationship between vascular phenomena and thermal exchange in the fingers. The variations of finger pulse amplitude provide an adequate and sensitive adjustment of thermal exchange since the effects of smoking a single cigarette can be detected by both PWA and calorimetric measurements in the finger.

Adult↗
PubMed1986

Non-invasive measurement of skin blood flow: comparison between plethysmography, laser-Doppler flowmeter and heat thermal clearance method.

A comparison was made between (a) a new probe measuring heat thermal (HTC), (b) plethysmography and (c) a Laser-Doppler (LDF) technique during changes in skin blood flow (SkBF) on six subjects, each participating in a single experiment. Increase of SkBF was induced by heating the body skin with an electric cover. Heat thermal clearance correlated well with the forearm blood flow (FBF) (r = 0.69-0.97) and with LDF measurements (r = 0.86-0.92) in each experiment, Laser-Doppler flowmeter also correlated well with FBF (r = 0.73-0.97). However, the relationship between HTC, LDF and FBF varied from one experiment to another. Values for HTC and for LDF at zero FBF, extrapolated from the regression relationships, ranged from 6.438 to 10.919 k, and from -0.37 to +0.17 volt respectively. The value for HTC at zero LDF extrapolated from the regression relationships ranged from 4.109 to 12.413 k. Values for HTC and LDF when blood flow to the arm was mechanically occluded ranged from 5.17 to 10.71 k and from 0.07 to 0.24 volt respectively. Thus HTC, LDF and FBF measurement of SkBF appear to produce the same response pattern during reflex cutaneous vasodilatation. Each of these three methods measured SkBF in different skin areas and at different depths in the skin, which might also explain the variability in their relationship.

Adult↗
PubMed1985

Heat loss and anticipatory finger vasoconstriction induced by a smoking of a single cigarette.

The effects of smoking of a single cigarette on finger vasomotion were investigated in 15 healthy subjects classified according to their smoking habit into one of 3 groups: heavy, light, and non-smokers. Finger pulse amplitude was recorded using a plethysmographic mercury gauge before, during and after cigarette smoking and finger heat loss evaluated using direct calorimetry before and after smoking. Heavy smokers showed a decrease of finger pulse amplitude at the sight of the cigarette and before the first puff. Finger pulse amplitude in light smokers decreased during cigarette smoking. In heavy smokers and light smokers finger heat loss decreased after smoking. In non-smokers, there was no change either in finger heat loss or in finger pulse amplitude. Anticipatory finger vasoconstriction in response to the sight of a cigarette may represent a pavlovian conditioning occurring in heavy smokers only.

Body Temperature Regulation↗
PubMed1985

Potentiated muscular thermogenesis in cold-acclimated muscovy duckling.

The capacity for nonshivering thermogenesis (NST) was examined in 26- to 27-day cold-acclimated (CA) muscovy ducklings reared for 21 days at 4 degrees C. Metabolic rate and integrated electromyographic (EMG) muscle activity were measured at ambient temperature ranging from -10 to 28 degrees C. Compared with controls reared at 30 degrees C, CA ducklings were more resistant to cold and had higher peak metabolic rate in extreme cold. Shivering threshold temperature of CA ducklings was 14.2 degrees C lower than lower critical temperature, whereas for controls the two temperatures were similar. Thus CA ducklings exhibited an NST in moderate cold. In addition, at temperatures that produced shivering, EMG activity in CA duckling muscle was lesser than that of controls, even at a higher metabolic rate. Because these ducklings are devoid of brown adipose tissue, these results indicated an increased thermogenic efficiency of muscular activity in CA ducklings.

Acclimatization↗
PubMed1984

[Surface analysis of intramuscular bioglass ceramic implants using pro ton-induced x-ray emission].

The method of the proton induced x-ray emission ( PIXE ) was used for the investigation of ion exchange processes on the surface of intramuscularly implanted Bioglass-Ceramics. This method allows a simultaneous analysis free from destruction in concentrations ranges of ppm for several elements. The measurements were carried out with different proton energy, in that manner a relative quantity analysis was possible in different layers. A durable two-layered surface already originates in a short time after the implantation on the implant interface. This one consists of a layer rich in calcium and phosphorus as well as a second zone rich in silicon. The meaning of this two-layered surface for the bio-activity and the bio-stability of the material is discussed.

Animals↗
PubMed1984

[Correlation between the measurement of PO2 by percutaneous route and the measurement of cutaneous irrigation by thermal clearance in the foot in chronic obliterative arteriopathies of the lower limbs].

Possible influence of skin circulation in percutaneous determination of pedal TcPO2 of patients with lower limbs arteriopathy was investigated. Findings demonstrated close correlation between TcPO2 and the morphology of the pulsatile signal on digital plethysmography in hyperemia, and the degree of lower limbs ischemia, particularly during the stage of permanent ischemia. Histograms of skin irrigation values measured by thermal clearance were similar in normal subjects and patients with lower limbs arteriopathy. Values for skin irrigation measured in this way failed to show linear correlations with TcPO2 values. These findings suggest that TcPO2 values reflect any global tissue ischemia at the measurement site and not cutaneous vascularization alone.

Arterial Occlusive Diseases↗
PubMed1982

Influence of thermoregulation on energy metabolism of the low birthweight infant.

UNLABELLED: By combining continuous measurements and recordings of (a) 02 consumption and CO2 production, (b) core, mean skin and temperature, (c) "radiative and convective" (R + C) heat loss, we have tried to assess the characteristics and effiency of different heating systems in the usual environment of an intensive care unit. PRELIMINARY RESULTS: minimal heat loss is obtained in an incubator with manual temperature control versus serocontrolled incubator on radiant heater; the radiant heater can maintain adequate core temperature but with higher than normal heat loss from the sides of the body and increased warming only of the skin facing the heater; metabotic rate measurements do not show any statistical difference between these various environments; both with an incubator and a radiant heater, a thin plastic sheet (used as heatshield) lowers "R + C" heat loss.

Body Temperature Regulation↗