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J P Dumont

Publications and source records attributed to J P Dumont.

15 recordsLinked to original sources
PubMed1986

Local inhibitor of the crayfish telson-flexor motor giant neurons: morphology and physiology.

The motor circuits that control telson flexion in the crayfish (Procambarus clarkii) include a curiously arranged sub-circuit: a premotor 'command' neuron excites a motor neuron via a trisynaptic pathway, but also inhibits (and prevents firing of) the motor neuron via a shorter latency pathway (Kramer et al. 1981 a). The premotor and motor neurons in this circuit have been previously identified (Kramer et al. 1981 a; Dumont and Wine 1985a, b; see Fig. 1). We have now identified a local interneuron that inhibits the motor neurons. The cell we studied is called the 'C' cell because of its distinctive structure (Figs. 2, 3). A single pair of bilaterally homologous C-cells was found in the last (6th) abdominal ganglion. The C-cells are invariably dye coupled to one another following injections of lucifer yellow into either one of them, and are frequently dye coupled to smaller axons in the 2nd, 3rd, and 6th nerves. In addition, some of the extensive branches of the C-cell extend out into the 6th nerve, where they are in close proximity to the axons of the motor neurons they inhibit (Fig. 3). Two kinds of evidence established that the C-cell directly inhibits the motor neurons. First, when simultaneous recordings were made from the C-cell and the motor neurons, spikes in the C-cell, no matter how evoked, were invariably followed, within 1.5 ms, by depolarizing IPSPs in the motor neuron (Fig. 6). Second, when the C-cell was hyperpolarized so that it could not fire, that same IPSP in the motor neuron was abolished (Fig. 6). The inhibitory pathway to the motor neurons must be fired at short latency in order to prevent firing caused by the trisynaptic excitatory input (Fig. 1). The C-cells were fired at short latency (less than 3 ms) by impulses in either of the escape command cells (Fig. 4), and at even shorter latency by impulses in the Segmental Giant of the 6th ganglion (SG6) (Fig. 5). It has been established elsewhere that the SGs are a major output pathway of the escape command cells; our results suggest that they may be the pathway for command-evoked firing of the C-cell. The C-cells are also excited by two descending, non-giant, flexion premotor neurons, called I2 and I3 (Fig. 5). The EPSPs from a single I2 or I3 impulse were subthreshold, but temporal and spatial summation of EPSPs from the non-giant pathway sometimes fired the C-cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1986

Combination chemotherapy with mitomycin and vindesine in advanced non-small cell lung cancer: a pilot study by the Lung Cancer Working Party (Belgium).

The combination of mitomycin plus vindesine in advanced non-small cell lung cancer induced an objective response rate of 23% in 43 evaluable patients: 33% in nonpretreated patients (nine responses among 27 patients) and 6% in pretreated patients (one response among 16 patients). Toxicity was tolerable. We conclude that the regimen was a moderately active and easy to administer treatment for advanced non-small cell lung cancer.

Adult↗
PubMed1985

Combination chemotherapy with adriamycin, etoposide, and cyclophosphamide for small cell carcinoma of the lung. A study by the EORTC Lung Cancer Working Party (Belgium).

The current study reports the results of Adriamycin (doxorubicin), etoposide, and cyclophosphamide (AVE) in small cell bronchogenic carcinoma. The overall rate of response was 82% in patients with limited disease and 66% in patients with extensive disease; complete remissions have been achieved in 20% of the patients with limited disease and in 7% of those with extensive disease. The median duration of survival was 14 months in patients with limited disease and 8.3 months in those with extensive disease. The results, and the analysis of literature, suggest that survival rather than response should be used to compare studies of chemotherapy in small cell bronchogenic carcinoma.

Adult↗
PubMed1981

[Decreased binding by isolated rat hepatocytes of asialo-haptoglobin after combination with hemoglobin].

The desialilation of 125I-labelled haptoglobin unmasks non-reducing galactose which has become terminal and permits its recognition and binding by isolated hepatocytes. However, the prior formation of an asialohaptoglobin-haemoglobin complex diminishes this property considerably. The explanation suggested is that there could either be a structural rearrangement of the complexed asialo-haptoglobin or steiric hindrance due to a masking of the galactose by the haemoglobin.

Animals↗
PubMed1981

[Repair of loss of substance from the nose with a two-pointed lozenge-shaped flap (author's transl)].

A lozenge-shaped resection is employed to obtain a flap consisting of two triangular elements having a common pedicle. The resulting flap has similar qualities to the one described by Esser-Zymany: available tissue is obtained at a distance from the lesion, with reduced torsion of the pedicle and without deformation of the intermediary zone; use can be made, if necessary, of the lax tissue in the different quadrants surrounding the pedicle; double locking of the graft is possible. The flap has the additional advantage that its borders can be easily adapted. The authors have used it in 16 out of 34 cases treated over a period of 18 months.

Aged↗
PubMed1980

Effect of streptozotocin diabetes on sialic acid content and glycoprotein binding of isolated hepatocytes.

The possible correlation between sialic acid content of hepatocyte plasma membranes, and their binding capacity was investigated. For that purpose, [3H] asialotransferrin binding was tested with hepatocytes from both normal and streptozotocin treated rats. The observed decrease in binding capacity was parallel to a decrease in the sialic acid content Insulin therapy restored simultaneously normal blood glucose level, hepatic membrane sialic acid content and binding capacity.

Animals↗
PubMed1979

Production of S-Methylthioacetate by Brevibacterium linens.

Volatile sulfur compounds production by eight strains of Brevibacterium linens isolated from cheeses was demonstrated: methanethiol, dimethyldisulfide, and 2,3,4-trithiapentane. Four of these strains also produced S-methylthioacetate, an important aroma component of smear-coated cheeses. It is the first demonstrated microbiological production of a thioester.

Journal Article↗
PubMedDate not supplied

Further observations showing the impact of the probenecid test in movement disorders.

Two patients with movement disorders are described and neurochemically studied. The first subject concerns a central anticholinergic syndrome in a 83 years old man treated with l-dopa and amantadine for red nucleus tremor. The second one is an association of parkinsonism and chorea in a 76 years old woman presenting with FAHR's syndrome. In both cases, CSF HVA levels were measured before and after oral probenecid load. The observations confirm the usefulness of this neurochemical strategy in order to classify aging patients with parkinsonism into dopasensitive and doparesistant groups.

Aged↗