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Biomedical subjects

B Guidet

Publications and source records attributed to B Guidet.

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

[Access of torsades de pointes in Legionnaires' disease: an uncommon adverse effect of erythromycin].

We report the case of a 77-year-old man with legionnaires's disease who, immediately after an intravenous infusion of one gram of erythromycin presented with wave burst arrhythmia with widening of the QT space. The blood level of erythromycin at the time of this adverse reaction was the same as the peak observed in young subjects after intravenous administration of this drug. Fourteen similar cases were found in the literature. In vitro and in vivo studies have shown that erythromycin may exert on the cardiac muscle fibres an electrophysiological effect similar to that of class I antiarrhythmic agents.

Aged↗
PubMed1991

[Pneumococcal pneumonia resistant to penicillin].

The authors report a case of community-acquired pneumonia in a patient with chronic obstructive lung disease. The initial antibiotic therapy consisted of an amoxicillin-clavulanic acid combination and intravenous macrolides. Twenty-four hours after admission, blood cultures were positive for pneumococcus. Pending the results of disc sensitivity tests, the antibiotic therapy was modified and amoxicillin alone was prescribed. Clinical deterioration then developed rapidly, as the pathogen was amoxicillin-resistant. Subsequently, the patient recovered under erythromycin therapy. As illustrated by this case, the emergence of pneumococci resistant, or showing low sensitivity to penicillins raises the problem of the antibiotic therapy to be used against community-acquired lung diseases.

Amoxicillin↗
PubMed1991

[Inhibitors of factor VIIIc and pregnancy. Review of the literature].

Circulating anticoagulants directed against factor VIII coagulant activity are very rarely encountered. Eighteen per cent of them have been described in the peripartum period of primiparae aged 28 years on average. The clinical signs are the same as those of constitutional haemophilia, but they differ in frequency. The most common of these signs are haematoma, ecchymoses and haematuria. The diagnosis is confirmed by prolongation of clotting time alone, presence of an anticoagulant in blood and specific assay of the deficient coagulant factor. These inhibitors are usually immunoglobulins of the IgG type. The cause and pathogenesis of the disease are unknown. Treatment consists of administering coagulant factors in haemorrhagic periods and immuno-suppressive therapy. Spontaneous remissions are frequent.

Adult↗
PubMed1990

Nordihydroguaiaretic acid inhibits urokinase synthesis by phorbol myristate acetate-stimulated LLC-PK1 cells.

Protein kinase C (PKC) activation is regulated by Ca2+, phospholipids, diacylglycerol (DAG) and fatty acids. Phorbol myristate acetate (PMA) which mimics the effect of DAG on PKC induces transcriptional activation of the urokinase-type plasminogen activator (u-PA) gene in LLC-PK1 cells. We examined in the present work the relationships between PKC activity, fatty acids, and u-PA synthesis in this cell line. We showed that H7, an inhibitor of PKC, inhibited the PMA-induced u-PA synthesis by LLC-PK1 cells. PMA-induced u-PA synthesis was enhanced by eicosatetraynoic acid (ETYA), a competitive inhibitor of both the lipoxygenase and cyclooxygenase pathways and inhibited by nordihydroguaiaretic acid (NDGA), an inhibitor of the lipoxygenase pathway. Three other unrelated lipoxygenase inhibitors (phenidone 100 microM, BW755 50 microM and diethylcarbamazine 50 microM) had no effect on u-PA biosynthesis. Two polyunsaturated fatty acids other than ETYA, arachidonic acid and linoleic acid, also potentiated the PMA effect and a lipoxygenase derivative, 12 hydroxyeicosatetraenoic acid (12 HETE), did not modify the basal and PMA-stimulated u-PA syntheses. PKC activity purified from cytosol of LLC-PK1 cells was stimulated by addition of 16 nM PMA in vitro and this effect was blunted by simultaneous addition of 5 microM NDGA. By Northern blot analysis using a pig u-PA cDNA probe we found that PMA increased the steady state level of u-PA mRNA after 2 h of incubation and that NDGA inhibited this effect. These data suggest that NDGA inhibits PMA-stimulated PKC activity in intact cells leading to a decrease of u-PA mRNA level and u-PA biosynthesis in PMA-stimulated LLC-PK1 cells. Polyunsaturated fatty acids have opposite effects.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

[Non-lactic metabolic acidosis].

The definition of metabolic acidosis (MA) is a primary decrease in plasma bicarbonate concentration. The visceral consequences are largely dependent on the degree of acidosis and the rapidity of its onset; they have been studied mainly in animal studies and therefore, extrapolation to the clinical situation should be cautious. The MA can be classified in two groups according to whether the anionic serum gap is increased or normal (hyperchloremic acidosis). The etiologies of the first group are lactic acidosis, the cetoacidoses and renal failure. The hyperchloremic acidoses usually result from gastro-intestinal bicarbonate losses; the biochemical diagnosis of rarer causes of hyperchloremic acidosis is facilitated by measuring the serum potassium, urinary pH and the urinary anionic gap. Although all causes of MA must be treated, the use of bicarbonate should be discussed in each individual case.

Acid-Base Equilibrium↗
PubMed1990

Capillary leakage complicated by compartment syndrome necessitating surgery.

A single episode of systemic capillary leak syndrome is reported in a HIV-positive patient. The shock had necessitated the infusion of large amounts of fluid with concomitant diffuse swelling and weight gain leading to compartment syndrome of both legs. This required surgical relief. The initial high hematocrit (62%) and low serum protein concentration (48 g/l) with normal factor V (molecular weight above 300,000) concentrations are the hallmark of capillary leak when they are associated with hypovolemic shock. It must be emphasized that fluid resuscitation may worsen the muscle damage with ultimate compartment syndrome. Therefore, it appears reasonable to monitor muscular pressure during volume expansion in patients with capillary leak syndrome, severe shock and muscular swelling.

Adult↗
PubMed1990

[Evaluation of the efficacy of plasma exchange in Leber's disease].

Amaurosis congenita of Leber is a hereditary optic neuropathy, usually bilateral, that quickly leads to blindness. There is no effective treatment. The inflammatory aspect of the papillary lesions in the early stage, in addition to the beneficial effect of plasma exchanges reported for other optic neuritides, led us to propose such a therapeutic regimen to 6 young adult men afflicted with the disease. This treatment was initiated early, before optic nerve atrophy occurred. The plasma volume exchanged was 3.2 +/- 0.5 liters/session and 4.2 +/- 1.8 (3 to 7) exchanges were performed. The exchanges were always well tolerated. Three patients subjectively reported improvement immediately following the exchanges but only one had some improvement of his visual acuity. However, a more sensitive evaluation of the ability to distinguish contrasts revealed improvement in patients whose visual acuity remained unchanged. This visual gain was lost 3 months later. Therefore, it appears that plasma exchanges are not the treatment of choice for this disease.

Adult↗
PubMed1990

[Acute respiratory distress caused by distal neoplastic pulmonary emboli].

In contrast to pulmonary parenchyma metastases or lymphangitic carcinomatosis, neoplastic emboli of small pulmonary arteries and capillaries frequently go unrecognized and are only discovered at autopsy. Five patients (48 +/- 12 years old) were admitted to 3 intensive care units for severe acute respiratory failure and died between the first and the tenth day following hospitalization. Each patient had a history of rapidly progressive dyspnea, and physical examination showed clinical evidence of right ventricular failure. The lungs were clear on chest X-rays and the ECG revealed sinus tachycardia with a right QRS axis. The mean partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were, respectively, 50.8 +/- 9.1 mm Hg and 22.2 +/- 2.4 mm Hg. A swan-Ganz catheter, inserted into 4 patients, revealed pulmonary arterial hypertension (55, 43, 37, 28) with capillary wedge pressure within the normal limits and cardiac output normal or low (3.0, 3.8, 4.4, 5.0 l/min). Pulmonary angiograms from each patient showed decreased distal lung perfusion without any proximal defects suggestive of pulmonary embolism. The inferior vena cava always appeared clear. Malignant cells were found upon autopsy (4 cases) in the lumina of the pulmonary arterioles and the primary site of the cancer was determined in 3 patients (2 hepatomas and 1 pancreatic carcinoma). The last patient had a known breast cancer with bone marrow metastases and clinical, hemodynamic and angiographic evidence of neoplastic emboli. The clinical course of neoplastic emboli can suggest acute pulmonary embolism, but the diagnosis can only be advanced after pulmonary angiography, especially if the patient is to have a cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

[Specificity and serum concentrations of tumor necrosis factor in septic shock].

Several lines of evidence implicate tumor necrosis factor (TNF), a cytokine produced by monocytes-macrophages, in the systemic manifestations of shock induced by Gram-negative bacteria. Whether the increase of circulating TNF levels is specific to septic shock as compared to sepsis without shock or to non-septic shock is still unclear. Since TNF values recorded at the time of admission to the hospital vary widely, statistical analysis has not been possible. Therefore, we postulated that the evolution of a patient's TNF serum level as compared to his initial value may better distinguish the survivor from the non-survivor than a single initial determination. Using a radioimmunoassay, we measured the TNF concentrations in the sera of 7 patients with severe infections without shock, 16 patients with septic shock and 8 patients with non-septic shock. Blood samples were drawn within the first 12 hours after the onset of shock. Patients with cancer, HIV infection, or under steroid therapy were excluded. Repeated measurements were made during the first 3 days of septic shock in 10 patients. The circulating TNF level, determined upon admission, appears to be neither specific nor predictive of the outcome of septic shock. In contrast, persistently high levels of circulating TNF seem to be well correlated with a poor prognosis, since 5 out of 6 patients with elevated TNF values died of septic shock.

Adult↗
PubMed1990

[Recurrence of atypical pulmonary pneumocystosis treated with pentamidine aerosol].

Two cases are reported of atypical relapses of pneumocystosis in AIDS patients treated with aerosol pentamidine for 14 and 22 months. These pneumopathies are unusual because of their pitted aspect and recurrent spontaneous pneumothoraxes in spite of repeated drainage. They are difficult to diagnose because bronchoalveolar lavage fluid is negative for Pneumocystis carinii, despite their presence in lung biopsies. Histological lesions vary, being granulomatous, necrotizing and invasive, with involvement of the pleura and lymph nodes. Although a highly effective therapy against P. carinii pneumonia, aerosol pentamidine may play a role in these atypical episodes: either by causing bronchial obstructions beyond which the pneumocytotic lesions cannot be reached by lavage and become necrotic, or by favoring the extrapulmonary spread of P. carinii.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Enhanced in vivo H2O2 generation by rat kidney in glycerol-induced renal failure.

Aminotriazole-mediated inhibition of catalase has been used in previous studies as a measure of in vivo changes in the hydrogen peroxide generation. Using this method, we found a significantly higher inhibition of renal catalase activity at various time points (30, 60, and 90 min) in glycerol-treated rats (a well-established model for myoglobinuric acute renal failure) compared with rats treated with aminotriazole alone. The greater inhibition in the glycerol-treated group was not due to differences in aminotriazole levels. We confirmed that catalase inactivation by aminotriazole was due to formation of catalase-hydrogen peroxide intermediate (compound I) because catalase inactivation was prevented by ethanol, a competitive substrate for compound I. There were no significant differences in the aminotriazole-induced inhibition of renal cortical catalase activity in control and uranyl nitrate-treated rats, suggesting that there was no enhanced generation of hydrogen peroxide in this model of acute renal failure. Taken together, these data provide evidence for enhanced generation of hydrogen peroxide in glycerol-induced acute renal failure and suggest that the enhanced generation of hydrogen peroxide in the glycerol-induced acute renal failure is not a result of nonspecific response to tissue injury.

Acute Kidney Injury↗
PubMed1987

Polycythemia in chronic obstructive pulmonary disease. A study of serum and urine erythropoietin and medullary erythroid progenitors.

In order to investigate the mechanism of polycythemia in chronic obstructive pulmonary disease (COPD), serum and urinary levels of erythropoietin and medullary erythroid progenitors were studied in 21 patients; nine were nonpolycythemic (hematocrit, 39 +/- 4 percent; red blood cell [RBC] mass, 28 +/- 5 ml/kg; forced expiratory volume in one second [FEV1], 0.6 +/- 0.1 L), and 12 patients were polycythemic (hematocrit, 52 +/- 7 percent; RBC mass, 46 +/- 7 ml/kg; FEV1, 0.9 +/- 0.3 L). Hypoxia was severe in both groups, with mean arterial oxygen pressure of 47 mm Hg. The following parameters of tissue oxygenation were not significantly different between the two groups: arterial and mixed-venous oxygen saturations; cardiac output; oxygen utilization coefficient; 2, 3-diphosphoglycerate, and carboxyhemoglobin level. The level of erythropoietin was measured by bioassay in vitro. The level was increased in the serum of 85 percent (18) and in the urine of 38 percent (8) of the patients. There was no significant difference between the nonpolycythemic and polycythemic groups. Without exogenous erythropoietin, none of the subjects showed spontaneous colonies of erythroid progenitors. The addition of one unit of erythropoietin induced a similar normal proliferation of erythroid progenitors in both groups. The absence of adaptative polycythemia in the nonpolycythemic group with severe hypoxia was seemingly related neither to a quantitative deficit of erythropoietin nor to a lack of sensitivity of erythroid progenitors to its action.

Aged↗
PubMed1987

Hemodynamic tolerance and plasma volume variations during plasma exchange. Replacement fluid: albumin alone or albumin plus gelatin?

Little is known about mechanisms of systemic hypotension frequently reported during plasma exchange (PE). Type of substitution fluids may interfere with hemodynamic tolerance. In a prospective study, right heart catheterization was performed during 18 PE by filtration with isovolumic substitution. Blood volume was measured with 51Cr tagged erythrocytes and plasma volume (PV) calculated from hematocrit. Substitution fluids were either albumin (A; n = 9) or A + gelatin (A + G; n = 9). In both groups, PE induces significant (p less than 0.01) decreases of mean arterial pressure: group A: - 21 +/- 14%; group A + G: - 23 +/- 15%; of pulmonary wedge pressure: group A: - 41 +/- 33%; group A + G: - 36 +/- 22%; of cardiac index: group A: - 38 +/- 18%; group A + G: - 25 +/- 15%. Plasma volume also decreases after PE: group A: - 13.5 +/- 4%; group A + G: - 18.5 +/- 4%. None of the variations are significantly different between the two groups. So we think that substitution with albumin alone has no advantage for hemodynamic tolerance.

Albumins↗