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Biomedical subjects

V Bach

Publications and source records attributed to V Bach.

10 recordsLinked to original sources
PubMed1991

Cardiovascular responses and electroencephalogram disturbances to intermittent noises: effects of nocturnal heat and daytime exposure.

During sleep, in thermoneutral conditions, the noise of a passing vehicle induces a biphasic cardiac response, a transient peripheral vasoconstriction and sleep disturbances. The present study was performed to determine whether or not the physiological responses were modified in a hot environment or after daytime exposure to both heat and noise. Eight young men were exposed to a nocturnal thermoneutral (20 degrees C) or hot (35 degrees C) environment disturbed by traffic noise. During the night, the peak intensities were of 71 dB(A) for trucks, 67 dB(A) for motorbikes and 64 dB(A) for cars. The background noise level (pink noise) was set at 30 dB(A). The noises were randomly distributed at a rate of 9.h-1. Nights were equally preceded by daytime exposure to combined heat and noise or to no disturbance. During the day, the noises as well as the background noise levels were increased by 15 dB(A) and the rate was 48.h-1. Electroencephalogram (EEG) measures of sleep, electrocardiograms and finger pulse amplitudes were continuously recorded. Regardless of the day condition, when compared with undisturbed nights, the nocturnal increase in the level of heart rate induced by heat exposure disappeared when noise was added. Percentages, delays, magnitudes and costs of cardiac and vascular responses as well as EEG events such as transient activation phases (TAP) due to noise were not affected by nocturnal thermal load or by the preceding daytime exposure to disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Relative and combined effects of heat and noise exposure on sleep in humans.

In a counter-balanced design, the effects of daytime and/or nighttime exposure to heat and/or traffic noise on night sleep were studied in eight healthy young men. During the day, the subjects were exposed to baseline condition (ambient temperature = 20 degrees C; no noise) or to both heat (35 degrees C) and noise. The duration of the daytime exposure was 8 h ending 5 h before sleep onset. The following nights, the subjects slept either in undisturbed (20 degrees C; no noise) or in noise, heat, or noise plus heat-disturbed environments. During the day, the various types of traffic noise were distributed at a rate of 48/h with peak intensities ranging between 79 and 86 dB(A). The background noise level was at 45 dB(A). At night, the peak intensities were reduced by 15 dB(A), the rate was diminished to 9/h, and the background noise was at 30 dB(A). Electrophysiological measures of sleep and esophageal and mean skin temperatures were continuously recorded. The results showed that both objective and subjective measures of sleep were more disturbed by heat than by noise. The thermal load had a larger impact on sleep quality than on sleep architecture. In the nocturnal hot condition, total sleep time decreased while duration of wakefulness, number of sleep stage changes, stage 1 episodes, number of awakenings, and transitions toward waking increased. An increase in the frequency of transient activation phases was also found in slow-wave sleep and in stage 2. In the nocturnal noise condition, only total number of sleep stage changes, changes to waking, and number of stage 1 episodes increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Changes in serum electrolyte and atrial natriuretic peptide concentrations, acid-base and haemodynamic status after rapid infusion of isotonic saline and Ringer lactate solution in healthy volunteers.

Opinions differ on the use of isotonic sodium chloride and Ringer lactate solution for extracellular volume depletion. We have compared changes in serum electrolyte concentrations and acid-base and haemodynamic status after rapid infusion of 2 litre of either isotonic sodium chloride or Ringer lactate solution in healthy volunteers. Changes within groups were small and statistically insignificant. Central venous pressure changes were associated with secretion of atrial natriuretic peptide, but this response was delayed.

Acid-Base Equilibrium↗
PubMed1990

Priming principle with atracurium.

In order to substantiate the "priming principle" discussion, 44 patients admitted for elective gynecological surgery under modified neurolept anesthesia were randomized into two groups. In group I, atracurium was administered by a priming technique in which 0.1 mg/kg was given i.v. and, after 6 min, 0.5 mg/kg. In group II was given an atracurium bolus injection of 0.6 mg/kg. In group I onset time (median 61 sec, range 44-160 sec) was significantly more rapid than in group II (median 83 sec, range 60-128 sec). The median train-of-four ratio in group I was 0.80 (range 0.43-1.00, n = 23), 6 min after the priming dose, in 30% of these patients the TOF ratio was above 0.90 and in 22% below 0.70. It is impossible to determine a fixed pretreatment dose per kg body weight owing to the large individual variation in neuromuscular depression. Modification of the priming principle using incremental small doses of non-depolarizing neuromuscular blocking agents, with anesthetic induction, when the train-of-four ratio is between 0.90 and 0.70 or when there is clinical signs of neuromuscular block, might be an alternative in situations where rapid induction is required and where the use of suxamethonium is contraindicated.

Adult↗
PubMed1979

Clinical and experimental evaluation of cefoxitin therapy.

30 patients were treated with i.v. cefoxitin (4-8 g/day), of which 20 had documented infections which included endocarditis (5), lung abscess (4), empyema (4), liver and subhepatic abscess (3), osteomyelitis (3), and pancreatic abscess (1). 14 patients had infections caused by anaerobic bacteria and 5 had endocarditis due to aerobic organisms. All but 2 patients with osteomyelitis of the mandible were cured. Adverse reactions were noted in 7 patients, mostly due to drug fever and leukocytosis; one had Coombs'-positive hemolytic anemia. The average serum cefoxitin levels were 24, 16, 12, and 4 microgram/ml at 1, 2, 3 and 4 h, respectively, and the average serum/pleural fluid ratio was 1:0.5 +/- 0.25. All anaerobic and aerobic isolates except one strain of Bacteroides fragilis were susceptible to cefoxitin at less than or equal to 32 microgram/ml. The concentration of cefoxitin in the tissues was measured in 8 rabbits; it was 4 +/- 1 microgram/ml in the heart and 2 +/- 0.5 microgram/ml in the femur and mandibular tissue, suggesting that the lack of response in cases of osteomyelitis could be due to inadequate antibiotic concentration in the bone. Our study suggests that cefoxitin can be used in the treatment of anaerobic infections and endocarditis due to susceptible organisms.

Abscess↗
PubMed1979

Cyclacillin: in vitro activity against aerobic and anaerobic bacteria.

Cyclacillin at 50 microgram/ml inhibited streptococci (100%), shigella (72%), and Bacteroides (B) fragilis ss fragilis (84%). At 100 microgram/ml it inhibited proteus (75%), B. fragilis (86%), and E. coli (50%). Cyclacillin was more effective than ampicillin against beta-lactamase-producing H. influenzae. The activity of cyclacillin was found to be more enhanced when tested in nutrient agar and Mueller-Hinton agar than in brain heart infusion agar.

Ampicillin↗
PubMed1977

In vitro activity of ticarcillin against anaerobic bacteria compared with that of carbenicillin and penicillin.

A total of 334 clinical anaerobic isolates were tested in an anaerobic glove box by the agar dilution technique for susceptibility to clinically achievable levels of ticarcillin, carbenicillin, and penicillin. Thirty-two micrograms or less of penicillin per milliliter inhibited 91% of all strains, whereas 100 mug of carbenicillin and ticarcillin per ml inhibited 95 and 98%, respectively. A total of 82% (85 strains) of Bacteroides were inhibited by penicillin, and 93 and 96% were inhibited by carbenicillin and ticarcillin, respectively. Thirteen (24%) of 55 strains of Bacteroides fragilis tested were resistant to 32 mug of penicillin per ml, and 6 (11%) and 3 (5%) were resistant to 100 mug of carbenicillin and ticarcillin per ml, respectively. Within the therapeutic range, ticarcillin was the most effective of the three penicillins tested against B. fragilis subsp. fragilis.

Anaerobiosis↗
PubMedDate not supplied

Cefoxitin therapy for bacterial endocarditis.

Of 22 patients who were suspected of having bacterial endocarditis and who were treated with cefoxitin intravenously (8-12 g per day), 12 were evaluated for responses to therapy. Ten patients had infections due to a single pathogen, and two had polymicrobial infections. Staphylococci were isolated from eight patients, and streptococci from four; both of these pathogens were susceptible to 2-16 micrograms of cefoxitin/ml. Staphylococcus aureus and four strains of anaerobic bacteria, including Bacteroides fragilis (minimal inhibitory concentration, 32 micrograms/ml), were isolated from one patient. The average level of cefoxitin in serum was 32.8 micrograms/ml (range, 14.5-64 micrograms/ml) at 1 hr after an intravenous dose of 2 g; after 5 hr the average level in serum was 8.5 micrograms/ml (range, 2-20 micrograms/ml). The mean (+/- SD) level of cefoxitin in myocardial tissues from eight rabbits at 1 hr following a 250-mg/kg dose of the antibiotic was 4 +/- 0.5 micrograms/g. On the average, patients were treated for 29 days (range, 14-40 days), and they became afebrile in 6.2 days (range, three to 20 days). Both clinical and microbiologic responses to cefoxitin therapy were excellent in 10 patients with monobacterial infections. Both patients with polymicrobial infections were not cured. One, who was infected with a mixed flora of anaerobes, died; the other was cured after surgical valvectomy. These results suggest that cefoxitin is effective in the treatment of endocarditis due to a single susceptible organism but that this antibiotic should be used with caution in patients whose endocarditis is caused by a mixed population of bacterial pathogens.

Adult↗