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Biomedical subjects

J Koller

Publications and source records attributed to J Koller.

At least 73 records · Page 4Linked to original sources
PubMed1991

Comparison of vecuronium- and atracurium-induced neuromuscular blockade in postpartum and nonpregnant patients.

The time-course of action of 0.1 mg/kg vecuronium and 0.5 mg/kg atracurium was investigated in nonpregnant and in postpartum patients within 4 days after delivery. The clinical duration of vecuronium, but not that of atracurium, was significantly prolonged in the latter group (P less than 0.001) and averaged 36 +/- 6 and 37 +/- 4 min for atracurium and 32 +/- 6 and 49 +/- 10 min for vecuronium in nonpregnant and in postpartum patients, respectively (mean +/- SD). In additional in vitro experiments in the rat phrenic nerve-hemidiaphragm preparation no difference could be observed in the neuromuscular blocking effects of vecuronium in postpartum and nonpregnant female rats. It is concluded that pregnancy-induced changes in liver blood flow and/or competition for the liver uptake of sexual hormones might interfere with the hepatic clearance of vecuronium in postpartum patients and thereby cause the observed prolongation of neuromuscular blockade.

Adult↗
PubMed1991

Acute macular neuroretinopathy after shock.

Acute macular neuroretinopathy is a rare disease that has been described mainly in women taking hormonal contraceptives. An association either with a viral illness or with the parenteral use of sympathomimetics was sometimes found. We describe its occurrence in a 22-year-old female following an anaphylactic shock after a bee sting, and in a 26-year-old female following a pregnancy complicated with vena cava syndrome and delivery by caesarean section. A combination of factors including hypoperfusion, Valsalva stress, estrogen-induced hematological and rheological changes, and alpha-adrenergic stimulation apparently provoked this clinical manifestation.

Adult↗
PubMed1990

[Initial experience with a new blood pump].

A new type of blood pump was tested in calves for 6 hours. The pump consists of a rigid housing with a trochoidal internal surface, an inlet and outlet, and two lateral walls. A two-corner piston rotating on an eccentric shaft, describes a trochoidal path, thus creating a gap seal, the gap measuring a constant 10-35 microns. The pump is driven by a watercooled DC motor. For right ventricular assist, a cannula is inserted into the right ventricle through the right atrium, and into the left ventricle for left ventricular assists. From a total of 10 experiments, two left ventricular assists, two right ventricular assists, and three biventricular assists were evaluated. The pump produced a pulsatile flow of 31 at 70 rpm. Energy requirements were 2.19 watts for left, 2.06 for right, and 7.26 for biventricular assists. Plasma hemoglobin remained as low as 10 mg/dl during monoventricular, and increased during biventricular assists to 20 mg/dl after 3 hours, and returned to 16 mg/dl after 6 hours. From these preliminary results it is concluded that this new rotary blood pump may be suitable as a circulatory assist device.

Animals↗
PubMed1990

[Plasma levels of atrial natriuretic peptide, cyclic guanosine monophosphate and renin following 7.5% NaCl + 6% hydroxyethyl starch or Ringer's lactate. A comparative study of 6 normal subjects].

Small-volume resuscitation with hypertonic saline in combination with dextran appears to be very successful in experimental animals, where better results are achieved than in animals treated with a traditional infusion regime. This effect is apparently related to improved organ blood flow due to reflex vasodilatation. This reflex is based on the arrival of hypertonic solution in the pulmonary circulation. The expansion of intravascular volume would seem to be of secondary importance. Atrial natriuretic peptide (ANP) is released from secretory granules located in atrial cardiocytes. Atrial distention appears to be the predominant stimulus triggering ANP production. In addition to the natriuretic and diuretic effects, ANP leads to vasodilation, especially when vascular tone is elevated; the sympathetic reflex seems to be attenuated. Cyclic Guanosine Monophosphate (cGMP) is an intracellular messenger and is partly released by ANP in the membrane-bound form. Renin excretion is highly influenced by ANP. The object of this study was to evaluate the influence of a hypertonic solution on this hormonal regulatory system. METHOD. This study compared a hypertonic sodium chloride solution (7.5%) in combination with hydroxyethyl starch (6%) (HH) to Ringer's lactate (RL). Six healthy volunteers received 4 ml/kg HH and 1 week later 500 ml RL. The infusion was administered in 20 minutes via a central venous catheter 70 cm in length. Blood pressure, heart rate, hemoglobin (Hb), hematocrit (Hk), colloid osmotic pressure (COP), sodium (Na+), chloride (Cl-), and plasma osmolarity were measured before starting and 5 and 30 min following infusion. At the same times ANP, cGMP, and plasma renin were also determined. RESULTS. Both groups showed no change in blood pressure or heart rate. The decrease of Hb, Hk, and COP in the HH and RL groups indicated the expansion of circulating plasma volume. HH infusion caused significant increases in ANP and cGMP, whereas plasma renin declined significantly. After RL infusion, ANP and renin values were very similar to the HH group except in one volunteer, who showed an extreme increase in ANP (760 pg/ml) 5 min after HH infusion. cGMP did not increase significantly in the RL group. On comparison of the two groups, only a significant difference in plasma osmolarity and in sodium and chloride levels was noted. CONCLUSION. We found that hypertonic NaCl (7.5%) with HH was well tolerated. Release of ANP and cGMP after HH infusion in healthy volunteers was not as high as expected, and the vasodilatory effect of hypertonic solutions was not explained by ANP or cGMP release in this investigation.

Adult↗
PubMed1990

[The dose-response relationship and time course of the neuromuscular blockade by alcuronium].

Although alcuronium has been in clinical use for almost 40 years, there is still considerable controversy in the literature regarding its neuromuscular blocking potency, the time course of the drug action and the side effects. The aim of this study was to investigate the dose-response relationship of alcuronium and to compare the time course of its neuromuscular effects with vecuronium following intubation doses of both compounds. METHODS. The study was carried out in two parts. In the first part 60 patients and in the second part 30 consenting ASA class I or II patients 20-60 years of age were included. The patients were undergoing elective gynecological or intra-abdominal operations. In the first part the patients received six different doses of alcuronium (60, 90, 120, 150, 180 or 210 micrograms/kg) in order to establish its dose-response relationship. Each dose was administered to ten patients. In the second part patients received either 300 micrograms/kg alcuronium (n = 15) or 100 micrograms/kg vecuronium (n = 15), and the time course of these two compounds (onset time, duration 25%, duration 75% and the recovery index) were compared. To test the reversibility, ten patients in each group received 30 micrograms/kg neostigmine at 25% recovery of T1. The neuromuscular effects of alcuronium and vecuronium were quantitated by EMG using the DATEX relaxograph. RESULTS. The log-logit analysis of the dose response data revealed an ED50 of 111 micrograms/kg and an ED95 of 250 micrograms/kg, which is in reasonable agreement with the measured effects following 120 micrograms/kg and 210 micrograms/kg alcuronium, resulting in 52 +/- 21% and 96 +/- 4% T1 depression, respectively. The onset time, duration 25%, duration 75% and spontaneous recovery index following 300 micrograms/kg alcuronium (5.0 +/- 3.4 min, 62 +/- 25 min, 119 +/- 38 min and 58 +/- 34 min) appeared to be significantly longer (P less than 0.05) than those observed after 100 micrograms/kg vecuronium (3.2 +/- 1.2 min, 33 +/- 7 min, 49 +/- 9 min and 18 +/- 7 min), respectively. The most striking finding of this study is the enormous individual variations observed in both neuromuscular potency and the time course of action of alcuronium. Following 150 micrograms/kg (routinely employed in daily clinical practice), the magnitude of T1 depression ranged between 19% and 100%. The same vast individual variations were observed in the time course of action following 300 micrograms/kg of alcuronium. The onset time, duration 25%, duration 75% and spontaneous recovery index ranged between 1.3 and 14 min, 22 and 110 min, 93 and 186 min and 32 and 116 min, respectively. CONCLUSIONS. The ED50 and ED95 values for alcuronium found in this study are in the same order of magnitude as 106.8 micrograms/kg and 135 micrograms/kg for ED50 and with 280 micrograms/kg for ED95, respectively, as reported by others. The long duration with slow recovery and the wide individual variation in the neuromuscular effects observed in our study have been reported earlier. Based on the above observations and because of the availability of better alternatives with fewer side effects, we conclude that alcuronium should be added to the list of obsolete neuromuscular blocking agents, together with gallamine and d-tubocurarine.

Adult↗
PubMed1990

[A new topical preparation for the treatment of burns. I. Technical aspects of preparation].

In the present paper some problems connected with the formulation of a topical preparation of the hydro-ointment type intended for the treatment of deep dermal burns were examined. Sixteen ointment bases containing hydroxypropyl-methylcellulose, hydroxyethylcellulose, Carbopol 934 and Pluronic F-127 as gel-forming substances were evaluated. The local anaesthetic agents carbizocaine and lidocaine served as active ingredients. Suitability of ointment bases was evaluated on the basis of their liberating capability for drugs, rheological properties and washability. The results show that an increase in the concentration of the gel-forming substance in the ointment resulted in a decrease in carbizocaine liberation. A decrease in the released amount of drugs occurred also after an addition of a humectant additive to the ointment base. The local anaesthetic agents under study decreased the viscosity of ointment bases. The highest coefficient of washability was found in the Carbopol ointment base. From the viewpoint of administration, the base with 1% Carbopol, or a combined base with 2% Methocel and 0.5% Carbopol proved to be most suitable.

Anesthetics, Local↗
PubMed1989

[The effect of donor conditioning and perioperative management of recipients on the initial and late function of kidney transplants].

On the basis of 88 consecutive cadaveric renal transplants, multiple variables concerning donor conditioning and perioperative recipient management which may have an influence on the occurrence of acute tubular necrosis (ATN), were analysed and their impact on long-term results assessed. Cold ischaemia time turned out to be the greatest risk factor and was seven hours shorter in patients with good initial function when compared with patients with ATN. Although actual one-year graft survival was similar in both groups, the postoperative course was more complicated in the ATN group and management more onerous. Furthermore, two patients of the initial non-function group died of complications directly related to renal replacement therapy. Seventeen hours cold ischaemia time was associated with more than 80% initial function. This time is sufficient to allow careful tissue typing and organ transportation.

Acute Kidney Injury↗
PubMed1989

Delayed neurological sequelae of high-tension electrical burns.

Five patients showed delayed spinal cord damage following high-tension electrical injury. Early specialist care of this complication is necessary and is best carried out in burn units. Our experience shows that recovery may be complete or only partial.

Adult↗
PubMed1989

Studies of the mechanism of tolerance induced by short-term immunosuppression with cyclosporine in high-risk corneal allograft recipients. I. Analysis of CTL precursor frequencies.

Transplantation of unmatched allogeneic corneas into highly vascularized recipient eyes under the cover of short-term immunosuppression with cyclosporine enables permanent engraftment. The aim of this study was to further elucidate the mechanism(s) underlying this tolerant state. In eight "high-risk" cornea recipients the clone sizes of donor-specific and third-party reactive cytotoxic T cell precursors were assessed by limiting dilution analyses before and at three and six months after transplantation. Acquired allograft tolerance in these patients was not accompanied by clonal reduction of donor-specific CTL-p, whereas in the case of an irreversible rejection the donor-specific CTL pool size was significantly enlarged. This donor-specific CTL-p increase could already be seen two months before clinical manifestation. These patterns differed from that of tolerant renal transplant patients, in whom marked and donor-specific reduction of CTL-p was observed. During rejection identical patterns with increasing donor-specific CTL-p frequencies were seen in both groups of patients. We conclude that induction of tolerance by short-term CsA to unmatched cornea grafts is not caused by clonal reduction of the effector precursor cell pool.

Adult↗
PubMed1989

Do donor age and cold-ischemia time have a detrimental effect on early pancreas-allograft function?

To study the impact of donor age and cold-ischemia time (CIT) on early graft function, we retrospectively divided the donors of 51 pancreas transplants performed between 1979 and 1987 at Innsbruck University Hospital into four groups according to donor age (greater than 45 yr and less than 15 yr) and CIT (greater than 8 h and less than 3 h). All organs were perfused with Eurocollins solution and stored at 4 degrees C. Fasting blood glucose levels and total amount of pancreatic juice produced over the first 3 postoperative days were recorded to assess graft function. No statistically significant difference was found between groups 1 and 2 and between groups 3 and 4. From these data, it is concluded that with the preservation method used, CIT can without a doubt be extended to at least 12 h, and a maximum donor age similar to that for the kidney can be adopted. This might not only enlarge the donor pool but also facilitate distant organ procurement.

Age Factors↗
PubMed1989

Classification of inhalation injuries.

A new system of classification of inhalation injuries called APB classification is proposed. The classification is based on the anatomical level of the injury (A), degree of pathological changes of the respiratory tract mucosa (P), extent and severity of associated cutaneous burns (B). The authors assume the classification would be of help in the analysis of severity, prognosis and treatment methods of inhalation injuries particularly in larger groups of burn patients.

Burns, Inhalation↗