Search PubMed⌕ Search

Biomedical subjects

T Rochat

Publications and source records attributed to T Rochat.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Tuberculosis 1992: current clinical aspects, epidemiology and diagnosis].

We review four different aspects of tuberculosis (TB), a disease which is making a comeback as a focus of medical attention. The diagnosis of TB in HIV infected individuals can be very challenging for the clinician and an increased number of side effects complicates treatment. Updated information in this area appears necessary for physicians who are in charge of HIV-infected patients. The "cursed duet" of TB and HIV infection is also responsible for the increase of TB in subsaharan Africa. Recent data are discussed in relation to this issue. Another problem for developing countries is the diagnosis and treatment of children's TB, which involves particular features as compared to the adult form of the disease. Finally, new diagnostic methods are now available from the laboratory. The detection of mycobacteria with the polymerase chain reaction has proven very useful in the diagnosis of tuberculous meningitis. Detection of tuberculostearic acid and mycobacterial antigen also represent important advances. The role of these techniques in the diagnosis of TB forms other than meningitis will need to be defined in the near future.

AIDS-Related Opportunistic Infections↗
PubMed1993

Childhood tuberculosis at a Swiss university hospital: a 2-year study.

The incidence of tuberculosis (TB) presenting to the University Hospital, Geneva, Switzerland, was studied over 2 years. Clinical data on all children receiving antituberculous drug therapy was collected. Of the 43 identified cases, 42% had active disease (i.e. clinical evidence of organ involvement), the remaining 58% being asymptomatic. All 43 children originated from countries other than Switzerland. Symptomatic, drug induced hepatitis necessitated temporary interruption of therapy in 2 children (5%). Contact screening yielded three new cases of pulmonary TB, three previously diagnosed cases and seven instances of a positive medical history in relatives living in other countries. Of the 34 families in this study, contact screening could not be completed in 8. The results of this study indicate that children with TB are primarily associated with families originating from countries other than Switzerland, particularly those in which TB remains endemic. Tuberculin skin testing should therefore be targeted at this group. Contact tracing has also been shown to be beneficial.

Adolescent↗
PubMed1993

Oxidative stress causes a protein kinase C-independent increase of paracellular permeability in an in vitro epithelial model.

To evaluate the response of an epithelial barrier to a moderate but sustained oxidative stress, we cultured monolayers of Madin Darby canine kidney cells on microporous filters and exposed them to the hypoxanthine-xanthine oxidase (HX-XO) reaction. The transepithelial permeability coefficient for mannitol (Pm) was assessed as a marker of paracellular permeability. When the oxidative stress was limited in intensity and duration (production of 10 nmol/ml/min O2- with generation of 467 +/- 30 nmol/ml H2O2 over 1 h), we observed an increase of Pm with a delay of several hours (324 +/- 65% of baseline by 6 h, P < 0.005). There was complete return to control values by 24 h. The increase of Pm did not appear to be related to a depletion of cellular ATP. Protein kinase C (PKC) activity did not increase, and the rise in Pm was not prevented by CGP 41,251, a specific inhibitor of PKC. By contrast, CGP 41,251 inhibited the Pm increase that was elicited by PDBU, a phorbol ester that activates PKC. In our model, we conclude that a reversible increase of paracellular permeability occurs after oxidative stress independently of ATP depletion or PKC activation. Other, as yet unknown mechanisms have to be involved in this process.

Adenosine Triphosphate↗
PubMed1993

Alterations in inspiratory and leg muscle force and recovery pattern after a marathon.

We measured lung mechanics and metabolic parameters, first in a series of 15 marathon (M) and 12 half-marathon (H) runners, before and 2.5 h after the race, in order to assess the running effect on respiratory muscles. Maximal static inspiratory (Pi) and expiratory (Pe) pressures, maximal voluntary ventilation (MVV), blood lactate (LAC), arterialized blood gases (ABG), plasma glucose (GLU), and, with a visual analog scale, subjective tiredness were assessed. Pi decreased in M and H without change in Pe, MVV, or lung mechanics; it was still abnormal 2.5 h after the race and did not correlate with LAC, ABG, training parameters, running times, or subjective tiredness. A second study of six other M compared Pi, Pe, adductor pollicis longus (Ppol), and triceps surae (Ptri) forces, aiming to: 1) assess the reproducibility of the prolonged Pi decrease without Pe change, 2) prove that such a decrease corresponded to a real reduction in inspiratory muscle force and was not due to a poor collaboration of the subjects, 3) correlate Pi decrease with the force loss of a potentially tired leg muscle: the triceps surae. We observed a significant and similar decrease in Pi and Ptri, but no change in Ppol and Pe. Moreover, the high correlation between Pi and Ptri diminutions suggested a similar recovery pattern for inspiratory and leg muscles. In conclusion, the prolonged decrease in Pi after such races is compatible with inspiratory muscle fatigue, which, as well as its recovery, is similar to leg muscle tiredness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Assessment of whole-body composition with dual-energy x-ray absorptiometry.

Dual-energy x-ray absorptiometry (DXA) allows noninvasive direct measurement of the three major components of body composition: lean body mass (LBM), fat body mass (FBM), and bone mineral body mass (BBM). To study the accuracy and short-term and long-term precision of body composition measurements, the authors measured body composition with DXA in 60 healthy young adults. Independent measurement of LBM (LBMK-40), obtained from the determination of the whole-body content of potassium-40 with a whole-body scintillation detector, was highly correlated with LBM determined with DXA (LBMDXA) (LBMK-40 = 1.069.LBMDXA,R2 = .996). Assessment of body composition in 10 patients with acquired immunodeficiency syndrome (AIDS) and 10 patients with cystic fibrosis was performed with DXA. The AIDS patients showed a marked decrease in LBM, while in patients with cystic fibrosis, LBM and BBM were decreased. DXA measurements of body composition appeared accurate and precise enough to be of clinical relevance in detecting specific alterations of body composition.

Absorptiometry, Photon↗
PubMed1992

Hyperoxia induces alkalinization and dome formation in MDCK epithelial cells.

We observed that confluent Madin-Darby canine kidney (MDCK) epithelial cells exposed to 95% O2 showed intensive dome formation, a manifestation of cell differentiation and transepithelial fluid transport, whereas cells exposed to 40% O2 or to normoxia did not. Hyperoxia-induced dome formation (HIDF) was preceded and accompanied by a significant rise in intracellular pH (pHi) on days 2 (7.53 vs. 7.42) and 3 (7.62 vs. 7.45), as compared with controls. Inhibition of the Na(+)-H+ exchanger by 0.1 or 1.0 mM amiloride caused 29 or 69% reduction of HIDF and completely abolished hyperoxia-induced alkalinization of the cells. HIDF was altered by modification of extracellular pH (pHo); there was a decrease by 84% with pHo 6.8, while pHo 7.8 led to earlier and more intensive dome formation (day 2, +472%; day 3, +27%). We also found that adenosine 3',5'-cyclic monophosphate (cAMP) was increased in hyperoxic cells, a change that was independent from the rise of pHi. We conclude that high-level hyperoxia induces dome formation in MDCK epithelial monolayers by a process involving activation of the Na(+)-H+ exchanger, together with increased intracellular cAMP.

Alkalies↗
PubMed1989

[Intermittent mechanical ventilation as home care].

Nocturnal mechanical ventilation (NMV) is a promising technique increasing survival and improving the quality of life of myopathic and kyphoscoliotic patients. The indications for NMV must be careful and the patients strictly selected. NMV is rarely useful in patients with pulmonary diseases, like COPD or restrictive disorders. When a professional medical and paramedical support is locally available, NMV can be undertaken at home. Negative and positive pressure ventilation can be used for NMV. Actually, tracheostomy can be replaced very often by a new type of positive pressure ventilation via a nasal face mask. We present here our series of 11 patients submitted to NMV and describe carefully the problems and the results of a 5-years experience with NMV in Geneva.

Adolescent↗
PubMed1988

Neutrophil cathepsin G increases permeability of cultured type II pneumocytes.

Neutrophils contribute to inflammatory injury in some types of acute and chronic lung disease. Among the injurious agents released by activated neutrophils are cationic proteins such as cathepsin G that may contribute to edema formation. Using cultured rat type II alveolar epithelium, we examined the effect of human neutrophil cathepsin G on permeability to mannitol and electrical resistance across the cultured epithelium. Monolayers maintained in control media alone had constant permeability to mannitol (4.5 +/- 0.3 X 10(-3) cm/h at base line and 4.4 +/- 0.3 X 10(-3) cm/h after 2 h). When monolayers were exposed to cathepsin G at concentrations of 5, 10, and 20 micrograms/ml, there was a progressive increase in mannitol permeability (120 +/- 26% increase at 5 micrograms/ml, 174 +/- 40% increase at 10 micrograms/ml and 301 + 116% increase at 20 micrograms/ml, P less than 0.001). The effect of cathepsin G on mannitol permeability was blocked by the presence of the polyanion-sulfated dextran, and the polycation protamine also increased permeability to mannitol 57 +/- 5% (P less than 0.001), suggesting a role for charge in this effect. Cathepsin G exposure also resulted in a progressive decrease in electrical resistance (67 +/- 2% base line after 15 min, 55 +/- 1% after 30 min, and 43 +/- 2% after 60 min). Cathepsin G at these concentrations was not cytolytic to the cells as measured by lactate dedrogenase release. These functional alterations were accompanied by increase in intercellular gaps in the monolayers seen on scanning electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Exercise induced asthma and endogenous opioids.

Concentrations of endogenous opioid peptides in the plasma are increased during exercise and these substances have been implicated in the pathogenesis of asthma induced by chloropropramide and alcohol in diabetic patients. This work was undertaken to determine whether exercise induced asthma might be mediated by endogenous opioids. Plasma beta endorphin, met-enkephalin, and adrenocorticotrophic hormone (ACTH) concentrations were measured in five asthmatic patients and five normal volunteers breathing cold air during exercise. In four of the patients the effect of an infusion of naloxone on FEV1 was also measured during exercise induced asthma. Exercise produced acute bronchoconstriction in all asthmatics, characterised by a fall in FEV1; whereas no change occurred in normal subjects. There was no difference in plasma met-enkephalin, beta endorphin, and ACTH concentration between the two groups. Infusion of naloxone neither prevented nor worsened exercise induced asthma. These data suggest that endogenous opioids probably do not play a part in the development of exercise induced asthma.

Adult↗
PubMed1985

Circulating endogenous opioids and ventilatory response to CO2 and hypoxia.

The role of endogenous opioids in the control of breathing is not yet well defined. Radioimmunoassays that measure beta-endorphin (BE) and met-enkephalin (MET) having recently become available, we decided to evaluate the possible relation between the blood levels of these two opioids and different hypercapnic and hypoxic ventilatory responses observed in a group of normal subjects. Ventilatory response to hypercapnia (n = 9) and to hypoxia (n = 7) were determined by classical rebreathing methods. A voluntary isocapnic normoxic hyperventilation test was used as a control. Basal levels of BE and MET did not correlate with the magnitude of the ventilatory response to either hypercapnia or hypoxia. Moreover, BE and MET levels measured repeatedly up to 30 min after each test did not change significantly. We conclude that circulating endogenous opioids do not play a role in the control of breathing in normal humans. These results do not rule out a possible role for these substances as locally released mediators.

Adult↗