Biomedical subjects

J P Lefèvre

Publications and source records attributed to J P Lefèvre.

At least 19 recordsLinked to original sources

PubMed2002

Decrease in ovalbumin-induced pulmonary allergic response by benzaldehyde but not acetaldehyde exposure in a Guinea pig model.

The pulmonary effects of two environmentally relevant aldehydes were investigated in nonsensitized or ovalbumin (OA)-sensitized guineapigs (GPs). Four-week-old male Hartley GPs, weighing about 400 g, were intraperitoneally injected with 1 ml of an NaCl solution containing 100 microg OA and 100 mg Al(OH)(3). They were then exposed to either acetaldehyde (200 ppb) or benzaldehyde (500 ppb) for 4 wk (6 h/d, 5 d/wk). At the end of exposure, GPs were challenged with an OA aerosol (0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL). Sensitized nonexposed GPs showed bronchial hyperresponsiveness to OA and an increased number of eosinophils in blood and BAL, together with a rise in total protein and leukotrienes (LTB(4) and LTC(4)/D(4)/E(4)) in BAL. In nonsensitized GPs, exposure to acetaldehyde or benzaldehyde did not induce any change in the tested parameters, with the exception of irritation of the respiratory tract as detected by histology and an increased number of alveolar macrophages in animals exposed to acetaldehyde. In sensitized GPs, exposure to acetaldehyde induced a moderate irritation of the respiratory tract but no change in biological parameters linked to the inflammatory and allergic responses. In contrast, exposure to benzaldehyde induced a decrease both in OA-induced bronchoconstriction and in eosinophil and neutrophil numbers in BAL, an increase in the bronchodilatator mediator prostaglandin E(2) (PGE(2)), and a decrease in the bronchoconstrictor mediators LTC(4)/D(4)/E(4). Further investigations are needed to determine if the attenuated response observed in sensitized GPs exposed to benzaldehyde is due to an alteration of the mechanism of sensitization or to a more direct effect on various mechanisms of the allergic response.

Acetaldehyde↗

PubMed1992

Decreased sialidase activity in alveolar macrophages of guinea pigs exposed to coal mine dust.

The origin of immune dysfunctions that are observed in pneumoconiotic miners still remains unknown. There is evidence that the carbohydrate moiety of membrane glycoconjugates is of primary importance in many functions of immunocompetent cells. The glycosylation, and especially the sialylation level of membrane components of various lymphocyte and macrophage subsets, vary depending on the state of cellular differentiation and activation. Sialidases, which may regulate the amount of sialic acids exposed on the cell membrane, can thus be considered as immunoregulatory enzymes. In this report, the sialidase activity has been measured in alveolar macrophages (AM) and in cell-free bronchoalveolar lavage fluid (BALF) from guinea pigs exposed for 4 months to coal mine dust at a concentration of 300 mg/m3. The samples were collected by bronchoalveolar lavage 2 months after cessation of exposure. The sialidase activity in the cell-free fluid and in the purified alveolar macrophages showed a 10-fold decrease (p less than 0.001). Kinetic parameters of the enzyme such as Km and optimum pH did not change. This changed activity was specific for sialidase, as two other lysosomal glycosidases, beta-galactosidase and N-acetylglucosaminidase, showed unchanged activities. These results suggest the possibility that, by inducing a decreased sialidase activity, exposure to coal mine dust may lead to a modified expression of AM membrane-associated sialic acids giving rise to altered immune functions (i. e., phagocytosis, antigen processing, response to cytokines, etc.).

Animals↗

PubMed1989

[Parkinson disease and cognitive evoked potentials].

Long latency auditory evoked potentials were recorded in 50 patients with Parkinson's disease, some case were also investigated by the Rapid Evaluation of Cognitive Functions test (RECF) and Trail Making A test (TMA). Latencies of P2, N2 and P300 waves were longer in the parkinsonian group than in a control group matched for age. Latencies of N2 and P300 waves were correlated significantly with scores for RECF and TMA presumed to be sensitive to organic brain lesions. On the other hand no significant correlation was found between RECF and P1 and P2 latencies. In addition, correlation was lacking between Verbal Automatism test scores, presumed to be resistant to organic brain lesions, and P300 wave latencies. Cognitive evoked potential (CEP) latency increases with age in normal subjects. In the parkinsonian group the coefficient of correlation between these two factors was lower but still significant. The parkinsonian patients with dementia as defined by DSM III criteria, or an RECF score of less than 46, showed longer N2 and P300 latencies but no significant difference in N1 and P2 latencies. In contrast, comparison of P300 and N2 wave latencies in depressed and non-depressed parkinsonian patients failed to show any significant difference. The bilateral akinetic forms had marked lengthening of P300 wave latencies and a lower TMA score. Neither the duration of the disease, type of treatment, duration of L-Dopa therapy significantly influenced the latency of cognitive event-related potentials.

Age Factors↗

PubMed1987

[Intracranial hypertension and hydrocephalus caused by spinal cord tumors. Apropos of 3 cases].

Three cases of spinal cord tumor, revealed by hydrocephalus, are reported. Two patients showed symptoms of increased intracranial pressure and the third one presented himself with ataxic gait without intellectual impairment nor incontinence. In two cases ventriculo atrial shunt was initially inserted and the correct diagnosis was made only later on myelogram because lombosciatalgia or syndrome of the cauda equina. Clinical outcome was satisfying after surgical removal of the tumor. The nature of which was a neurinoma of the cauda equina; a lumbar intradural granuloma and an ependymoma of the cauda equina. The mechanism by which spinal cord tumors raised intracranial hypertension is discussed.

Adolescent↗

PubMed1987

[Cutaneous ulcerations and osteolysis in the carpal tunnel syndrome].

A case of carpal tunnel syndrome with skin ulcerations and osteolysis is reported. Such cases are unusual. There was a sensory and motor deficit with chronic ulcerations on the palmar surface of the third phalanx of the medius. The distal phalanx of the forefinger had been lost due to osteolysis. Surgical treatment is said to be followed by a healing of the ulcerations.

Aged↗

PubMed1984

[Morvan's fibrillary chorea and acrodynic syndrome following mercury treatment].

A 31 year-old inhabitant of French Guiana was prescribed mercuric iodide per os for two and a half months. Shortly before the end of the treatment he developed fasciculations in the trunk and particularly the lower limb muscles, distal painful paresthesias with vasomotor disorders, episodes of excessive perspiration and palmoplantar erythema, moderate fluctuating hypertension, progressive loss of weight and irritability with insomnia. Clinical and electrical signs of neuropathy were lacking. The clinical picture was that of Morvan's fibrillary chorea with acrodynia, the conditions of onset strongly suggesting a mercurial intoxication. Blood and particularly urine mercury levels were elevated. Administration of dimercaprol (BAL) considerably increased urinary excretion of mercury and there was progressive improvement and finally recovery after two months of BAL treatment. This case exemplifies the possible co-existence of fibrillary chorea and acrodynia. Whereas in many cases of fibrillary chorea a precise etiology cannot be determined, the affection can be induced by mercury as by gold administration. The fact that cases of fibrillary chorea due to mercury poisoning are rarely reported may be the result of individual patient hypersensitivity or particular metabolic absorption and excretion features of mercury. This case cannot be included within the continuous activity syndrome of muscle fibers described by Isaacs, since muscle contractures were absent and there was associated acrodynia. Moreover, there was no latent polyneuropathy, in spite of the intense fasciculations. It must be concluded, therefore, that in spite of its rarity fibrillary chorea should keep its semiologic autonomy.

Acrodynia↗

PubMed1983

[Spinal meningeal hemorrhage of tumor origin].

Intraspinal tumors with subarachnoid hemorrhage are exceptional. They are most often localized at the cauda equina. Ependymoma is the most common tumor. Low back pain followed by headache (Fincher syndrome) should suggest hemorrhage originating from a low lesion.

Adolescent↗

PubMed1983

[Optokinetic nystagmus and the Tensilon test in myasthenia].

Horizontal optokinetic nystagmus was measured before and after the intravenous administration of 10 mg of Tensilon in 12 patients with myasthenia gravis; 11 patients showed an increase of amplitude; this measure seems to be a reliable test for the diagnosis of myasthenia but the increase of frequency of optokinetic nystagmus is less specific. The increases of amplitude in the same patient may show important variations between the two eyes and depending on the direction of nystagmus; however, the greatest response is often observed in the optokinetic nystagmus which was initially the weakest.

Adolescent↗

PubMed1983

[Plasmocyte dyscrasia with polyneuropathy, polyendocrinopathy and polyadenopathy].

A 72 years old, male complains difficulty in walking, a peripheral neuropathy of four limbs is found. Clinical examination shows a peripheral lymphadenopathy predominating in left inguinal nodes. A malignant IgA k plasmocytoma is seen on lymph node biopsy. There is no pathological plasmocytosis on bone trephine biopsy. Bone radiographies are normal. Immunoelectrophoreses finds a monoclonal IgA lambda protein of little abundance without lowering of other immunoglobulins. Insufficiency of adenohypophysis clinically suspected, is confirmed by static and dynamic tests as well as anomaly of glucose tolerance. Biopsies of skin, muscle and nerve show neither plasma cell infiltrate nor amyloid deposit. Evolution is stabilized during 12 months by an hematosarcoma type treatment which must be stopped because of bad hematologic tolerance. This interruption is followed by a fast severe evolution that leads to death in few weeks. This case as comparable with those reported by japanese authors in Far East and of which rare cases have been reported in non japanese people. It seems that the association of a non myelomatous plasma cell dyscrasia of uncertain malignancy with peripheral neuropathy, endocrinic, cutaneous and various visceral signs must be individualized. It could be considered as a particular paraneoplastic syndrome more especially as in many case the cure of the plasma cell proliferation has been followed by disparition of visceral signs.

Aged↗

PubMed1982

[Involvement of oculomotor nerves. A little-known complication of Horton's disease].

Third, fourth and sixth cranial nerve palsy is a less common complication of giant cell arteritis than ischemic optic neuritis. Nevertheless, it occurs in at least 10% of cases. A case of giant cell arteritis with third nerve palsy which resolved under corticosteroid therapy is reported. The incidence of ocular complications is assessed from a review of the cases previously seen in the department and of data from the medical literature. The authors believe that the index patient has ischemic neuritis rather than myositis. It is concluded that giant cell arteritis should be considered at an early reversible stage.

Aged↗

PubMed1977

[Temporal arteritis and rhizomelic pseudo-polyarthritis. Clinical aspects and nosologic problems. Apropos of 48 cases].

The authors report 40 cases of temporal arteritis, of which 16 were associated with pseudo-polyarthritis, and 8 cases of polyarthritis alone. The clinical picture of temporal arteritis in the elderly, includes headaches in 95% of cases, clinical changes in the superficial head arteries in 75% of cases, joint and muscle signs dominated by pseudo-polyarthritis in 40% of cases; general signs were practically constant. A major inflammatory syndrome was also constant. From the histological point of view, there was pan-arteritis with giant cells, and their wide diffusion is shown by the presence of eye signs in 27.5% of cases, brain signs in 10% of cases, and extra-cephalic vascular signs in 10%. The relationship in classification between temporal arteritis and polyarthritis of the roots of the limbs is recalled. The course is long, the duration of corticosteroid therapy should never be less than two years; relapses are common but the mortality appears low.

Aged↗

PubMed1977

[Encephalopathy due to organomercuric compounds].

A 27 year old agricultural worker presented about one month after treating cereal seeds with an alcoxyalkyl mercurial derivative, an encephalopathy with a confusional state, a cerebellar stato-kinetic syndrome, an intention tremor and grand mal epileptic fits. Treatment with dimercaprol produced a clinical improvement on the fourth day with a fall in blood mercury from 3.5 mug to 2.2 mug whilst urinary excretion of mercury remained low. A fortnight later the patient was completely cured. Although less common than collective poisoning by ingestion, organo-mercurial encephalopathies due to occupational exposure are a real danger although it is not known whether the relative rareness of published cases is due only to lack of observance of security rules or to individual sensitivity which might be due to increased absorption of mercury through the lungs or skin. This case shows that although alkyl mercurial derivatives are reputed to be the most dangerous, alcoxyalkyl derivatives may also cause encephalopathies. Also, as long as non-toxic substances remain unavailable for use in agriculture, one should emphasise the necessity of careful observance of the security rules during manipulation of these products.

Adult↗

PubMed1975