[The most significative parameters for the diagnosis of focal neuropathy of the cubital nerve in the elbow]. / Parámetros más significativos para el diagnóstico de la neuropatía focal del nervio cubital en el codo.

OBJECTIVE: Determine the diagnostic validity of the most usual neurophysiological procedures in the examination of compressive neuropathies and/or ulnar nerve entrapment at the elbow. PATIENTS AND METHODS: A prospective observational study was carried out over a period of one year which included 19 patients with clinical features compatible with entrapment/compression of the ulnar nerve at the elbow, their neurophysiological diagnosis and surgical confirmation. We also studied 49 patients who were attended in our clinic for other reasons not related to disorders of the ulnar nerve. The variables studied were: maximum rate of motor conduction above the elbow; the amplitudes between spikes and the area between the first negative deflection and the last positive spike of the responses at the wrist and above the elbow. RESULTS: In the group of persons without disorders of the ulnar nerve the average rate of motor conduction was 58.07 m/s, with a confidence interval of 53-65. In the group of patients with specific clinical features the average rate of motor conduction was 47.26 m/s, with a confidence interval of 43.74-50.77. No relation was found between age and pathology, although rate of motor conduction was related to the presence of pathology. CONCLUSIONS: It was seen on logistical regression that the main variables for prediction of the presence or absence of pathology in a person were firstly motor conduction and secondly the amplitude index.

Characterization of the sarcoplasmic reticulum k(+) and Ca(2+)-release channel-ryanodine receptor-in human atrial cells.

Since the role of sarcoplasmic reticulum (SR) in the E-C coupling of mammalian atrial cells has long been a subject of debate, biochemical, electrophysiological and immunological assays were performed in order to define and compare the properties of the Ca(2+)-release channel-ryanodine receptor (RyR)-from atrial and ventricular tissues. Cardiac SR preparations from human, canine and ovine tissues were compared using [(3)H]ryanodine binding, channel reconstitution into planar lipid bilayers and Western blot analysis involving RyR antibodies. [(3)H]ryanodine binding assays revealed a K(d)value of; 2.5 n M for all investigated cardiac tissues. Bound [(3)H]ryanodine was Ca(2+)-dependent with similar EC(50)values of 0.43, 0.49 and 0.79 microM for human atrium, canine ventricle and ovine atrium, respectively. However the density of binding sites was 4.5 times lower in atrial than in ventricular tissues. Beyond the presence of selective K(+)channels (gamma=188 pS) recorded in the SR enriched fraction of human atrium, the activity of a large conducting (gamma=671 pS) cationic channel was also observed. The latter displayed typical characteristics of Ca(2+)-release channels which were activated by 10 microM free [Ca(2+)] and 2 m M ATP. Western blot analysis revealed the presence of the RyR2 isoform in atrial and ventricular samples whereas no immunoreactivity was detected with specific RyR1 and RyR3 antibodies. Our results, obtained at the molecular level, are consistent with the presence of functional SR in human atrial cells. The human atrial Ca(2+)-release channel displays binding and regulating properties typical of the RyR2 isoform.

Combined surgery for coronary artery disease and pheochromocytoma.

PURPOSE: To report a case of severe coronary artery disease complicating pheochromocytoma, managed with combined coronary artery bypass grafting (CABG) and adrenalectomy. CLINICAL FEATURES: A 55-yr-old woman presented with poorly controlled hypertension and investigation revealed an active pheochromocytoma of her left adrenal gland. During medical preparation for adrenalectomy, she developed an acute myocardial infarct complicated with unstable angina. This required urgent CABG, and combined surgery for the triple vessels coronary artery disease and the pheochromocytoma was planned. We explain the details of medical preparation before surgery and the anesthetic considerations during the surgical procedure. Postoperative recovery was normal and no complication occurred. Even if the pheochromocytoma was malignant, her urinary catecholamines two months after the surgery were normal and remain normal after more than two years of follow-up. CONCLUSION: We report a patient who underwent combined CABG and adrenalectomy for pheochromocytoma. The CABG was done first, followed by the adrenalectomy with invasive monitoring. The procedure was well tolerated with cure of the two underlying conditions. So we propose that combined procedure should be considered in this clinical setting.

[Visual evoked potentials (VEP). Current perspectives]. / Potenciales evocados visuales (PEV). Perspectivas actuales.

INTRODUCTION: The objective of this study is to describe current tendencies in the recording and interpretation of visual evoked potentials (VEP). In the introduction we describe the history of the three main classical schools and the modern methodology which combines them, so as to study the photopic and scotopic systems together and thus be better able to determine the origin of the underlying pathology. MATERIAL AND METHODS: We describe recording techniques using flash and chequer-board and a strategy for study of the visual pathway. RESULTS: The application of this technique is described for pathologies in which its findings are of particular interest: Silent multiple sclerosis, Parkinson, hepatic encephalopathy, dementia and psychiatric disorders in which certain neurotransmitters play a part; visual acuity; coma and brain death; cortical blindness. A separate section deals with paediatrics, in view of its special characteristics. We call for a return to the use of this technique with great future diagnostic potential.

Beta-adrenergic signal transduction and contractility in the canine heart after cardiopulmonary bypass.

OBJECTIVE: Impaired beta-adrenergic signal transduction has been proposed as a mechanism contributing to myocardial depression after cardiac surgery. This study determined the changes in the beta-adrenergic system in a model of postoperative myocardial dysfunction induced by myocardial ischaemia and reperfusion under cardiopulmonary bypass (CPB). Those changes were then related to contractility and responsiveness to beta-adrenergic stimulation. METHODS: Four groups of dog hearts were studied: 7 hearts harvested immediately after anaesthesia induction (control group representing the preoperative cardiac condition); 6 hearts harvested after three hours of chest opening by sternotomy (open chest group serving as control for the effects of anaesthesia and surgery); 7 hearts harvested during CPB after 30 minutes of global ischaemia (ischaemia group); and 10 hearts from dogs submitted to one hour of CPB involving 30 minutes of global cardiac ischaemia, harvested 30 minutes after CPB (ischaemia-reperfusion group). Myocardial membranes were prepared to assess: (1) beta-adrenergic receptor density using the radioligand [125I]iodocyanopindolol; (2) GTP-sensitive adenylate cyclase activity and its regulation by isoprenaline and forskolin; (3) G protein levels, using an immunoblotting technique. Ventricular trabeculae or papillary muscles served to assess contractility and responsiveness to isoprenaline. RESULTS: The control and open chest groups had comparable beta-adrenergic receptor density, adenylate cyclase activity and cardiac contractility. In the ischaemia group, the left ventricular membranes had a 55% decrease in receptor density as compared to the controls (P < 0.005), similar GTP-sensitive adenylate cyclase activity and significantly lower adenylate cyclase responses to stimulation with isoprenaline and forskolin. In the ischaemia-reperfusion group, a 144% increase in the left ventricular receptor density was found as compared to the controls (P < 0.005), with a 70% increase in GTP-sensitive adenylate cyclase activity (P < 0.05), a similar adenylate cyclase response to isoprenaline and a 61% increase in response to forskolin (P < 0.005). As compared to the controls, the ischaemia and ischaemia-reperfusion groups had comparable Gs alpha levels, but markedly decreased Gi alpha-2 and Gi alpha-3 levels. The baseline tension of the isolated muscles in the ischaemia and ischaemia-reperfusion groups was comparable, but was 61% and 47% lower than the controls, respectively (P < 0.05). The maximal isoprenaline stimulated tension in the ischaemia and ischaemia-reperfusion groups was 66% and 36% lower than the controls, respectively (P < 0.05 between all groups). CONCLUSIONS: The beta-adrenergic system is severely depressed during global cardiac ischaemia under CPB, but recovers to supranormal values after CPB. However the increased cAMP generation by myocardial membranes after CPB is associated with decreased tension generation by corresponding cardiac muscles. Thus decreased contractility after CPB may be better explained by cellular alterations distal to cAMP generation rather than by changes in the beta-adrenergic system.

Hemolysis during cardiopulmonary bypass.

Hemolysis of red blood cells is a problem during cardiopulmonary bypass. The present study was undertaken to evaluate the influence of the priming solution and of the initial acceleration of the pump on red blood cell trauma and hemolysis. Eighty adult patients undergoing coronary artery grafting with cardiopulmonary bypass (CPB) were randomly assigned to one of four groups according to the nature of the priming solution and the initial speed of CPB flow (time from the start to the full calculated flow): group 1, lactated Ringer's (LR) with 5% dextrose (5%D), 1 minute; group 2, LR5%D, 2 minutes; group 3, LR, 1 minute; group 4, LR, 2 minutes. Plasma hemoglobin was found to be 4 times higher in group 1 than in the three other groups (P less than 0.001). It is concluded that there is an interaction between the presence of glucose in the priming solution and the initial acceleration of pump flow. The combination of LR5%D prime with a short time interval to full pump flow leads to a significant degree of hemolysis.

Staphylococcus aureus mediastinitis: prognostic usefulness of an early medicosurgical therapy.

Six cases of acute Staphylococcus aureus mediastinitis after median sternotomy were reported. Five resulted from an asymptomatic disseminator of S aureus present in the operating room. Each case was characterized by an acute bacteremic phase, occurring after a mean interval of 8.2 +/- 1.7 days after the surgical procedure; within 24 to 36 hours all patients had a temperature above 39 degrees C, toxic appearance, and marked leukocytosis. Pericicatricial inflammation was moderate, instability of the sternum was present in only two patients, and chest roentgenogram was not helpful in making an early diagnosis. No risk factor for mediasinitis in connection with the perioperative or postoperative periods was noted in cases compared with a control group of 103 patients. All strains of S aureus were susceptible in vitro to the antibiotic regimen used in prophylaxis. All patients underwent early surgical reopening of the mediastinum within 47 +/- 15 hours after the first sign of acute mediastinitis. Mediastinal debridement and continuous irrigation-suction with dilute povidone-iodine solution were associated with intravenous antistaphylococcal therapy for a period of four to six weeks. All patients survived and no recurrence was observed, a finding we think due to early diagnosis and aggressive medicosurgical therapy.

A six-year study of the Omniscience valve in four Canadian centers.

Stimulated by the recent controversy over the Omniscience valve, we conducted a follow-up study on 413 hospital survivors in whom this prosthesis was implanted at four Canadian centers from 1979 to 1985. One hundred forty-seven underwent aortic valve replacement (AVR), 203 had mitral valve replacement (MVR), 10 had tricuspid valve replacement (TVR) and 53 underwent multiple valve replacement (45 AVR + MVR, 5 MVR + TVR, and 3 AVR + MVR + TVR). The mean age was 50.8 +/- 13 years (range, 2 months to 75 years). Follow-up of 96% was achieved for a mean of 2.6 years and a maximum of 6 years with a total of 1,076 patient-years. Complications were defined and graded according to severity. Analyses were performed to yield linearized and actuarial rates for complications. There were 30 late deaths (2.8% per patient-year). At 5 years, the actuarial survival was 89 +/- 3% (AVR, 89 +/- 3% and MVR, 91 +/- 3%). Percentages for freedom from each complication are as follows: endocarditis, 96 +/- 1% (AVR, 96 +/- 2% and MVR, 98 +/- 1%); periprosthetic leak, 99 +/- 0.6% (AVR, 98 +/- 1% and MVR, 99 +/- 0.6%); thrombotic complications, 87 +/- 3% (AVR, 84 +/- 6% and MVR, 90 +/- 3%); valve thrombosis 99.4% (AVR and MVR, 100%); anti-coagulant-related hemorrhage, 94 +/- 2% (AVR, 97 +/- 2% and MVR, 94 +/- 2%); and all valve-related complications, 77 +/- 3% (AVR, 77 +/- 6% and MVR, 79 +/- 4%). Reoperation was required at the rate of 1.2% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)

Localized hypertrophic osteoarthropathy due to arterial graft sepsis from an enteroprosthetic fistula.

The case of a 73-year-old man with localized left-lower-limb hypertrophic osteoarthropathy in association with aortic left-iliac-artery bypass and enteroprosthetic fistula was studied. The patient presented first with massive gastrointestinal bleeding and with pain and swelling of his left leg. He was hospitalized on numerous occasions for recurrent episodes of bacteremia involving enteric flora; hypertrophic osteoarthropathy and aortoduodenal fistula were documented before surgery. Symptoms and signs of hypertrophic osteoarthropathy were markedly alleviated after removal of the infected prosthesis. A review of the literature revealed seven additional patients with a similar presentation. The diagnosis of infected arterial graft with enteroprosthetic fistula may be extremely difficult, and a delay in this diagnosis may be lethal. Awareness of this uncommon association may lead to prompt diagnosis and early surgical therapy.

Urethral stricture following cardiovascular surgery: role of urethral ischemia.

The incidence of urethral stricture has been surprisingly high following cardiovascular surgery in the last few years. We conducted a prospective study on 68 male patients undergoing cardiovascular surgery to determine the main factor(s) responsible for the development of urethral stricture. The penile-brachial pressure index was checked by strain gauge plethysmography. We found that urethral strictures developed in 15 patients (22 per cent) within an average of 3 months after cardiovascular surgery. Of these patients 13 had a penile-brachial index of 0.6 or less and complained of erectile impotence. A latex type of catheter was used in 11 and a silicone catheter in 4 of these 15 patients for urinary drainage. We conclude that urethral ischemia has an important role in the development of stricture, particularly when a latex urethral catheter is used for drainage. We recommend that a vascular penile study should be done in patients with erectile impotence undergoing an open heart operation, and that serious consideration should be given to the use of a cystocatheter diversion the night before the operation in those with a penile-brachial index less than 0.6. We strongly recommend the use of a silicone catheter in all other patients undergoing open heart surgery with hypothermia.

Role of urethral ischemia in the development of urethral strictures after cardiovascular surgery: a preliminary report.

A high incidence of urethral stricture was noted following cardiovascular surgery. In an attempt to elucidate factors predisposing to the occurrence of urethral stricture, we studied the penile blood flow in 7 patients presenting with strictures after cardiovascular surgery. Of these patients 5 had penile-brachial pressure indexes less than 0.5 and 6 had weak or absent erections. Of 14 patients studied prospectively by penile blood flow 2 had a low penile-brachial pressure index and suffered urethral strictures 6 weeks after cardiovascular surgery. This finding suggests that urethral ischemia could be a predisposing factor for the development of urethral strictures after cardiovascular surgery.

Urethral stricture after cardiovascular surgery, a retrospective and a prospective study.

In a review of our cases presenting with urethral stricture we noted a high incidence following cardiovascular surgery. A retrospective study was done, including 87 patients treated for urethral stricture and 304 undergoing open heart surgery during the same period, to search for a possible etiologic factor. A prospective study also was done on 98 patients subjected to cardiovascular surgery. Strictures developed in 17.5 per cent of 63 patients who had a urethral catheter placed for urinary diversion at operation compared to none of 35 who had a suprapubic cystocatheter. We believe that the urethral catheter is at least partly responsible for stricture formation. Associated factors, for example urethral ischemia, may be contributory.

Congenitally corrected transposition in a patient with situs inversus, atrioventricular discordance and mesocardia (I,D,D).

The clinical, hemodynamic and angiographic features of a patient with situs inversus, atrioventricular discordance, corrected transposition of the great arteries (I,D,D) and mesocardia are presented. A review of the literature concerning corrected transposition of the great arteries in situs inversus is included. The incidence of associated cardiovascular and electrocardiographic anomalies is compared with that found in corrected transposition of the great arteries in situs solitus; special surgical aspects of the above cases are also discussed.

[Urethral stenosis following cardiac surgery]. / Sténoses uréthrales postchirurgie cardiaque.

87 cases of urethral stenosis were treated over a two year period. This study was motivated by the high incidence of urethral stenosis after cardiac surgery. The patients were classified into four groups; urological surgery, cardiovascular surgery, medicine and other surgical specialties. The mean age was 60. It is easy to explain the development of urethral stenosis following endoscopic urological surgery, but rather more difficult, following cardiac surgery. The patients undergoing cardiac surgery were compared with those having a transurethral resection of the prostate. Neither traumatic catheterisation, urinary infection, prolonged catheterisation nor any factors specific to cardiac surgery could be implicated. The number of stenoses of the penile urethra was similar to the number of stenoses in the bulbar urethra. The critical period is within the first three months following surgery. Two hypotheses have been proposed to explain the pathogenesis of urethral stenosis after cardiac surgery: a hypersensitivity of the urethral mucosa combined, perhaps, with episodes of ischaemia. In order to verify the first hypothesis, the authors undertook a prospective study. Two groups of patients were chosen at random: 45 had a urethral catheter, 28 had a cystocatheter; 4 cases of urethral stenosis developed after the urethral catheter and there were no cases with the cystocatheter.

[Surgical treatment of sternal tumors]. / Tratamiento quirúrgico de los tumores de esternón.

Sternal tumors are rare. The surgical indication in case of metastasis is only justified if the primitive tumor is considered cure and with solitary metastasis. The en-block surgical resection must be based on pre-operative exploration in which a thoracic CAT SCAN has a very important role to determine the extent of the tumor and the anatomico-pathological control of the margin of resection during surgery. The reconstruction using methyl-methacrylate plate is interesting because of its rigid mounting by a moldable substance during surgery, being radiotransparent, inert and well-tolerated by the organism. On high sternal position it contributes to stabilize the scapular belt and assures mediastinal protection. The authors present a case of a partial sternectomy due to metastatic thyroid carcinoma with en-block resection and reconstruction by a methyl-methacrylate moulded plate.

[Conduction and origin of evoked potentials in the somesthetic pathway (author's transl)]. / Conducción y origen de los potenciales evocados en la vía somestésica.

In 24 normal subjects, sensory conduction velocity increased progressively from the distal to the proximal segments of the peripheral nervous system. In the central somatosensory pathway, sensory impulses slowed down at a rate much greater than what could be expected from just the three known synaptic delays (1 ms each) in medulla, thalamus and somatosensory cortex. The present data point to the special characteristic of conduction in the thalamo-cortical axons as the main cause for the deceleration observed in the central somatosensory pathway. A conduction velocity of 14 m/s has been calculated for this last segment. However it is also possible that sensory conduction in the medial lemniscus might be reduced in relation to the conduction values in the peripheral segments.

[Alterations of previous potentials of somatosensory cerebral evoked potential after lesions of the brain-stem (author's transl)]. / Alteración de los potenciales previos del potencial evocado somatosensorial en lesiones de tronco encefálico.

The characteristics of previous potentials of somatosensory evoked potential in 12 patients with lesions of the brain-stem and in 24 normal individuals have been studied. Lesions of the brain-stem were confirmed by means of computerized axial tomography, arteriography or necropsy. According to data reported by other authors somatosensory evoked potential is anteceded by three previous potentials with central latencies of 10, 12, and 14 milliseconds. Brain-stem lesions which do not involve the medial lemniscus showed normal potencials, while extensive lesions of the protuberance abolish P-12 potential and increase central latencies of P-14 and somatosensory evoked potential. P-12 potential originates in the medial lemniscus and P-14 potential in the thalamic nuclei. The present results confirm the interest of previous potentials of somatosensory evoked potential, as well as other neurophysiologic techniques, in the evaluation of lesions of the brain-stem.

Neurophysiological assessment of alpha pattern coma.

Somatosensory evoked potentials, blink reflexes, and H wave reflexes, were recorded on several days from three patients with alpha pattern coma. Coma was secondary to cardiac arrest in two cases and to brainstem infarction in one. Results are compatible with damage to the brainstem reticular formation with sparing of thalamo-cortical circuits as the main physiopathological characteristic of alpha pattern coma. This condition should not be regarded as a discrete entity when establishing the prognosis of patients in coma, since they only differ from other patients in coma from the point view of the EEG record.