[Bilateral pneumothorax in a young woman after acupuncture]. / Dubbelzijdige pneumothorax na acupunctuur bij een jonge vrouw.

A 30-year-old woman presented at the emergency department with severe bilateral chest pain and shortness of breath. The complaints began after acupuncture treatment along the spine and paraspinal region of the thorax the previous day. Further examination revealed bilateral pneumothorax. Two days after insertion of chest drains, the patient was able to leave the hospital in a good condition. Bilateral pneumothorax after acupuncture of the thorax is a rare complication and its precise incidence is unknown. Acupuncturists as well as general practitioners and emergency room physicians should be aware that acupuncture of the thorax can lead to unilateral as well as bilateral pneumothorax.

Pulse oximeter-induced digital injury: frequency rate and possible causative factors.

OBJECTIVE: To study the frequency rate of and factors associated with pulse oximeter-induced digital injury (PIDI). DESIGN: Prospective descriptive study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: All patients with a length of stay of >2 days. INTERVENTIONS AND MAIN RESULTS: We monitored 125 patients by using a pulse oximeter with a nondisposable clip-on probe changed every 3-4 hrs from one finger to another. Daily inspection was performed with special attention to digital injury. Factors implicated in the pathogenesis of PIDI, such as vasopressor therapy, hypotension, hypoxia, hypothermia, and arterial cannulation of the radial or ulnar artery were recorded daily. A total of 22 patients received norepinephrine and dopamine, 34 patients were given dopamine, and 69 patients did not receive vasoactive drugs. PIDI developed in 6 of 125 patients, five in the norepinephrine/dopamine group, one in the dopamine group, and none in the patients not receiving vasopressors. When comparing the frequency rate of PIDI in patients receiving norepinephrine (5 of 22) with patients not receiving norepinephrine (1 of 103) the relationship between the use of norepinephrine and PIDI is significant (p < .001). However, this relationship may also be explained by the fact that patients in the norepinephrine group were more severely ill than patients not requiring norepinephrine were. This is reflected by a higher median severity of illness score (Simplified Acute Physiology Score II) (p = .001), median duration of hypotension (p < .001), median number of saturation drops (p < .001), and higher mortality rate (p < .001). Hypothermia did not occur in any of the patients. There was no significant difference between the median right-left difference in duration of arterial cannulation between the two subgroups (p = .8). In all surviving patients, PIDI healed without permanent damage. CONCLUSIONS: In the studied population of critically ill patients in a surgical intensive care unit, the frequency rate of PIDI was 5% (6 of 125). Although an association with the use of norepinephrine was found, this small number of cases does not allow definite statistical conclusions concerning a relationship between the possible causative factors and PIDI. However, severely ill patients, as indicated by their need for more aggressive vasopressors, are more likely to develop PIDI. In survivors, PIDI healed without sequelae.

Outcome in patients requiring renal replacement therapy after surgery for ruptured and non-ruptured aneurysm of the abdominal aorta.

OBJECTIVES: to study the course of postoperative acute renal failure requiring renal replacement therapy (RRT) in patients with ruptured (RAAA) and non-ruptured (EAAA) aneurysm of the abdominal aorta (AAA) and to investigate the predictive value regarding outcome of parameters collected during the illness. DESIGN: retrospective study in a university hospital. MATERIALS AND METHODS: the records of 42 patients, 21 with RAAA and 21 with EAAA, were reviewed. RESULTS: overall mortality was 69%, 71% for RAAA patients and 66% for EAAA patients. RRT was started 9 (2-28) days - median (range) - postoperatively and continued during 9 (2-50) days. Renal function recovered in nine of the 13 survivors after 18 (2-50) days. Length of ICU stay was 50 (2-132) days for survivors vs. 19 (6-56) days for non-survivors. The systemic inflammatory response syndrome (SIRS) or need for vasoactive support was associated with poor outcome and the ability to wean from vasoactive or ventilatory support with improved outcome. CONCLUSIONS: RAAA and EAAA patients requiring postoperative RRT both had a high mortality. The ICU stay of non-survivors was shorter than that of survivors, who had a 75% chance of regaining renal function. The ability to wean from ventilatory and inotropic support may be of help in the clinical management of patients requiring RRT after AAA surgery.

Adrenocortical function in patients with ruptured aneurysm of the abdominal aorta.

OBJECTIVE: To investigate adrenocortical function in patients with ruptured aneurysm of the abdominal aorta. DESIGN: Prospective clinical investigation. SETTING: Surgical intensive care unit in a university teaching hospital and intensive care unit in a general hospital. PATIENTS AND PARTICIPANTS: 54 patients with a documented rupture of the abdominal aorta. INTERVENTIONS: A short adrenocorticotrophic hormone (ACTH) stimulation test was performed. MEASUREMENTS AND RESULTS: Patients were studied within 24 h of admission to the hospital. Blood samples for the measurement of cortisol and ACTH were collected at 0800 h. Subsequently 0.25 mg tetracosactrin (Synacthen) was injected i.v. and after 60 min cortisol measurement was repeated. The criterion for a normal short ACTH test was: stimulated or unstimulated cortisol levels > or = 0.55 mumol/l. For the group as a whole, an unstimulated plasma cortisol level of 0.76 mumol/l was comparable to that in other groups of critically ill patients with similar severity of illness. Between survivors and non survivors, significant differences were found between unstimulated plasma cortisol levels (0.70 vs 1.03 mumol/l), stimulated plasma cortisol levels (1.00 vs 1.30 mumol/l), and plasma ACTH levels (72 vs 133 ng/l). One patient did not meet the criteria for normal adrenocortical function: unstimulated plasma cortisol 0.26 mumol/l, stimulated plasma cortisol 0.47 mumol/l. CONCLUSIONS: In the patients studied with ruptured aneurysm of the abdominal aorta, adrenocortical response was comparable to that in other groups of critically ill patients with similar severity of illness. High cortisol levels were associated with mortality. One patient did not meet the criteria for normal adrenocortical function but survival without steroid treatment.

A double-blind randomized multicenter dose-ranging trial of intravenous streptokinase in acute myocardial infarction.

Intravenous streptokinase administration is now a widely applied therapy for patients in the early hours of acute myocardial infarction (AMI). The dosages used do not appear to be based on comparative clinical investigations. Therefore a double-blind randomized trial was carried out to establish the optimal dose of streptokinase. A total of 189 patients who had symptoms of AMI for less than 4 hours were treated with 200,000, 750,000, 1,500,000 or 3,000,000 IU streptokinase intravenously. At coronary angiography 2.8 +/- 2.7 hours (mean +/- standard deviation) after the start of streptokinase infusion, patency of the infarct-related coronary artery was observed in 38, 75, 60 and 82% of the patients, respectively, in the 4 groups. The result of the dosage of 200,000 IU was significantly poorer than that of the other dosages (p less than 0.01). The result of a dosage of 3,000,000 IU was significantly better than that of 1,500,000 IU (p less than 0.05), but the differences with 750,000 IU were not significant. Blood transfusion was required in 4 patients (2%), distributed over the 4 groups in 0, 2, 1 and 1 of the patients. One patient had major bleeding; this patient had been treated with 750,000 IU. The 3-month mortality-rate in the whole study population was 5%. Thus, of the 4 doses of streptokinase tested, 750,000 IU is the minimal therapeutic dosage, and the arguments for 1,500,000 IU as standard therapy for comparison with other fibrinolytic drugs are poor. The best results in this study were achieved with 3,000,000 IU, but further research will be needed to establish the efficacy and safety of this new regimen.

The electric potential field around cytochrome c and the effect of ionic strength on reaction rates of horse cytochrome c.

1. The electric potential fields around tuna ferri- and ferrocytochrome c were calculated assuming that (i) all of the lysines and arginines are protonated, (ii) all of the glutamic and aspartic acids and the terminal carboxylic acid are dissociated, and (iii) the haem has a net charge of +1e in the oxidized form. 2. Near the haem crevice high values for the potential (greater than +2.5 kT/e) are found. Consequently, electron transfer via the haem edge is favored if the oxidant or reductant is negatively charged. 3. The inhomogeneous distribution of charges leads to a dipole moment of 244 and 238 debye for oxidized and reduced tuna cytochrome c, respectively. Horse cytochrome c has dipole moments of 303 (oxidized) and 286 (reduced) debye. 4. A line through the positive and negative charge centres, the dipole axis, crosses the tuna cytochrome c surface at Ala 83 (positive part) and Lys 99 (negative part). The direction of the dipole axis of horse cytochrome c is very similar. Since the centre of the domain on the cytochrome c surface, which is involved in the binding to cytochrome c oxidase, is found at the beta-carbon of the Phe 82 in horse cytochrome c (Ferguson-Miller, S., Brautigan, D.L. and Margoliash, E. (1978) J. Biol. Chem. 253, 149--159) it is suggested that the direction of the dipole is of physiological importance. 5. The activity coefficients of horse ferri- and ferrocytochrome c were calculated as a function of ionic strength using a formula derived by Kirkwood (Kirkwood, J.G. (1934) J. Chem. Phys. 2, 351--361). 6. Due to the high net charge at pH 7.5 the influence of the dipole moments of horse ferri- and ferrocytochrome c on the respective activity coefficients can be neglected at I less than or equal to 50 mM. 7. Using the Brønsted relation the effect of ionic strength on reaction rates of horse cytochrome c was calculated. Good agreement is found between theory and experimental results reported in the literature.

The reduction of porphyrin cytochrome c by hydrated electrons and the subsequent electron transfer reaction from reduced porphyrin cytochrome c to ferricytochrome c.

1. Hydrated electrons, produced by pulse radiolysis react with porphyrin cytochrome c with a bimolecular rate constant of 3-10(10) M-1 S-1 at 21 degrees C and pH 7.4. 2. After the reduction step an absorbance change with a half-life of 5 microns is observed with the spectral range of 430-470 nm. A relatively stable intermediate then decays with a half-life of 15 s. 3. The spectrum of the intermediate observed 50 microns after the generation of hydrated electrons shows a broad absorption band between 600 and 700 nm and a peak at 408 nm. The spectrum is attributed to the protonated form of an initially produced porphyrin anion radical. 4. Reduced porphyrin cytochrome c reacts with ferricytochrome c with a bimolecular constant of 2-10(5) M-1- S-1 in 2 mM phosphate pH 7.4, at 21 degrees C and of 2 - 10(6) M-1-S-1 under the same conditions but at 1 M ionic strength. It is proposed that electron transfer in an analogous exchange reaction between ferrocytochrome c and ferricytochrome c occurs via the exposed part of the haem.

Mechanism of the reaction of hydrated electrons with ferrocytochrome c.

1. The hydrated electron reacts with ferrocytochrome c to form an unstable intermediate. This intermediate decays in a first-order manner to give, in the first instance, a product which has a similar absorption spectrum in the range 400-610 nm as normal ferricytochrome c. 2. At 21 degrees C the rate constant for the reaction of hydrated electrons with ferrocytochrome c at pH 7.4 (2 mM phosphate buffer) is (3.0 +/- 0.3) = 10(10) M-1 - S-1. As the pH is increased above pH 8.0 the rate constant steadily decreases. The dependence of the rate constant on pH can be explained if ferrocytochrome c has a pK of around 9.2. 3. At 21 degrees C and pH 7.4, the rate constant for the decay of the intermediate is (1.40 +/- 0.15) - 10(5) S-1. This reaction shows no pH dependence in the range 6-2-11.0. 4. A mechanism is proposed whereby the central metal atom of the ferrocytochrome c is oxidased and a thioether bond is reduced. The resulting ferricytochrome c species then slowly develops an absorbance at 606 nm due to the attack of the sulfhydryl group on the haem.

The kinetics of the reduction of cytochrome c by the superoxide anion radical.

1. At neutral pH ferricytochrome c is reduced by the superoxide anion radical (O2-), without loss of enzymatic activity, by a second order process in which no intermediates are observed. The yield of ferrocytochrome c (82-104%), as related to the amount of O2- produced, is slightly dependent on the concentration of sodium formate in the matrix solution. 2. The reaction (k1 equals (1.1+/-0.1) - 10(6) M-1 - s-1 at pH 7.2, I equals 4 mM and 21 degrees C) can be inhibited by superoxide dismutase and trace amounts of copper ions. The inhibition by copper ions is removed by EDTA without interference in the O2- reduction reaction. 3. The second-order rate constant for the reaction of O2- with ferricytochrome c depends on the pH of the matrix solution, decreasing rapidly at pH greater than 8. The dependence of the rate constant on the pH can be explained by assuming that only the neutral form of ferricytochrome c reacts with O2- and that the alkaline form of the hemoprotein is unreactive. From studies at pH 8.9, the rate for the transition from the alkaline to the neutral form of ferricytochrome c can be estimated to be 0.3 s-1 (at 21 degrees C and I equals 4 mM). 4. The second-order rate constant for the reaction of O2- with ferricytochrome c is also dependent on the ionic strength of the medium. From a plot of log k1 versus I1/2-(I + alphaI1/2)-1 we determined the effective charge on the ferricytochrome c molecule as +6.3 and the rate constant at I equals 0 as (3.1+/-0.1) - 10(6) M-1 - s-1 (pH 7.1, 21 degrees C). 5. The possibility that singlet oxygen is formed as a product of the reaction of O2- with ferricytochrome c can be ruled out on thermodynamic grounds.

The mechanism of reduction of cytochrome c as studied by pulse radiolysis.

1. The reaction of hydrated electrons with ferricytochrome c was studied using the pulse-radiolysis technique. 2. In 3.3 mM phosphate-buffer (pH 7.2), 100 mM methanol and at a concentration of cytochrome c of less than 20 muM the reduction kinetics of ferricytochrome c by hydrated electrons is a bimolecular process with a rate constant of 4.5-10-10 M-1-S-1 (21 degrees C). 3. At a concentration of cytochrome c of more than 20 muM the apparent order of the reaction of hydrated electrons with ferricytochrome c measured at 650 nm decreases due to the occurrence of a rate-determining first-order process with an estimated rate constant of 5-10-6s-1 (pH 7.2, 21 degrees C). 4. At high concentration of cytochrome c the reaction-time courses measured at 580 and 695 nm appear to be biphasic. A rapid initial phase (75% and 30% of total absorbance change at 580 and 695 nm, respectively), corresponding to the reduction reaction, is followed by a first-order change in absorbance with a rate constant of 1.3-10-5 S-1 (pH 7.2, 21 degrees C). 5. The results are interpreted in a scheme in which first a transient complex between cytochrome c and the hydrated electron is formed, after which the heme iron is reduced and followed by relaxation of the protein from its oxidized to its reduced conformation. 6. It is calculated that one of each three encounters of the hydrated electron and ferricytochrome c results in a reduction of the heme iron. This high reaction probability is discussed in terms of charge and solvent interactions. 7. A reduction mechanism for cytochrome c is favored in which the reduction equivalent from the hydrated electron is transmitted through a specific pathway from the surface of the molecule to the heme iron.

Dependence of the G value for radical production on the physical state.

Collagen was modified in several different ways which supplied a number of different samples. Their chemical composition (amino acid composition) was nearly equal; the physical properties (molecular weight and molecular organization) were different. The production of free radicals in these compounds was studied quantitatively with the electron spin resonance method. Differences in radical yield of at most a factor of 5 were observed. The results could be explained by assuming the presence of a radical-turnover process during irradiation, and the occurrence of a fast physical process of energy migration in ordered systems.