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Biomedical subjects

P Allard

Publications and source records attributed to P Allard.

At least 109 records · Page 6Linked to original sources
PubMed1993

[Multicystic renal dysplasia with ectopic implantation of the ureter in boys. Apropos of 6 cases].

The prevalence of multicystic dysplastic kidney has increased since the development of antenatal ultrasound diagnosis. Even though, the rarity of symptomatic forms and case reports of spontaneous regressions antenatally or after postnatal ultrasound follow-up have reduced indications of nephrectomy which is less and less appropriate. However, discovery of ectopic ureteric implantation in boys makes certain additional investigations as intravenous pyelography, cystography and ultrasound, essential before making any therapeutic decision. Nevertheless, some cases remain undescriptible. In these cases, operative opacification of any patent ureter can provide more precise information about ureteric implantation. Lastly, only a dissection and resection as complete as possible of any patent ureter and pelvic cystic dilatation can prevent subsequent complications.

Child, Preschool↗
PubMed1992

Studies on ribonucleoside-diphosphate reductase from Escherichia coli. The product dCDP is a competitive inhibitor and functions as a spectroscopic probe for the substrate binding site; demonstration by enzyme kinetics and 1H NMR.

Ribonucleoside-diphosphate reductase (EC 1.17.4.1) from Escherichia coli consists of two protein subunits, R1 of 171.5 kDa and R2 of 86.8 kDa, and catalyzes the reduction of all four common ribonucleoside diphosphates. In a search for ligands that bind weakly to the enzyme active site and may be in fast exchange suitable for NMR studies, we have found that the product dCDP is a competitive inhibitor. Kinetics with CDP as substrate shows Km = 4.8 x 10(-5) M and dCDP inhibits with Ki = 1.6 x 10(-4) M. With an assumed diffusion limited binding rate approximately less than 10(9) M-1s-1, the dissociation rate of dCDP would be approximately less than 10(5) s-1. In 1H-NMR experiments studying linewidths, i.e. spin-spin relaxation, dCDP is indeed demonstrated to be in fast exchange. Enzyme subunit R1 causes a line broadening of dCDP resonances. Unexpectedly less broadening was observed when subunit R2 combined with R1. No paramagnetic interaction from the tyrosyl radical of R2 could be detected. It is concluded that dCDP is a promising NMR probe for studies of active-site properties of the enzyme.

Binding Sites↗
PubMed1992

Binding of the competitive inhibitor dCDP to ribonucleoside-diphosphate reductase from Escherichia coli studied by 1H NMR. Different properties of the large protein subunit and the holoenzyme.

Ribonucleoside-diphosphate reductase (EC 1.17.4.1) from Escherichia coli consists of two nonidentical subunits, proteins R1 and R2. The binding of the product dCDP to protein R1 and to the holoenzyme R1R2 has been studied by means of 1H-NMR spectroscopy. In presence of the effector dTTP at 25 degrees C, dCDP was found to be in rapid exchange between the binding sites and the solvent which results in a broadening of the dCDP resonances. When both proteins R1 and R2 are present, so that the complex R1R2 is formed, a smaller broadening is observed than with protein R1 alone. No further linewidth decrease was observed when the [R2]/[R1] ratio exceeded 1. The binding constant of dCDP to R1 or R1R2 is the same, Kd = 0.9 mM. The smaller broadening of the dCDP resonances observed with the complex R1R2 as compared with R1 may be explained by the combination of two effects: (a) the overall tumbling time of the protein will increase when going from R1 to R1R2, which will cause the broadening to increase correspondingly, and (b) a twofold decrease of the number of binding sites in rapid exchange, which will decrease the broadening by a factor of 0.5. The effect of R2 without iron (apoR2) is reduced compared with native R2, probably because of some denatured proteins, while a C-terminal peptide from R2 did not cause any narrowing at all.

Binding Sites↗
PubMed1992

Bronchogenic carcinoma in patients with pulmonary histiocytosis X.

Five cases of bronchogenic carcinoma were observed among 93 patients with pulmonary histiocytosis X (Hx). Mean age at the time of diagnosis of Hx was 42 years; on the average, cancer occurred 10.5 years later. All patients were smokers and continued to smoke heavily at the time of diagnosis of cancer. Comparison of the five cases associating Hx and lung carcinoma with a group of 88 control patients suffering from Hx alone suggested that smoking played the predominant role in the pathogenesis of cancer. In fact, among the four patients with Hx and carcinoma older than 45 years, tobacco consumption was significantly greater (64.7 +/- 37 pack-year, mean +/- SD) than that of the 15 control patients of the same age with only Hx (40.8 +/- 11.6, p less than 0.01). In light of this good correlation, the diagnosis of Hx strongly advocates stopping tobacco smoking and long-term medical follow-up.

Adolescent↗
PubMed1992

Running gait impulse asymmetries in below-knee amputees.

In running, large gait asymmetry is expected due to the inability of the foot prosthesis to comply with the kinematic demands and produce a powerful plantarflexion moment. In this work, interlimb asymmetry in below-knee (BK) amputee running gait was assessed for one rigid and three flexible keel prostheses, using vertical and anteroposterior ground reaction forces and respective impulses. Nine BK amputees and 6 controls participated in this study. The running speed was monitored by two light sensitive detectors while the ground reaction forces were measured with a Kistler force plate. Between the prosthetic side and the sound limb the impulse indicator showed greater asymmetry than the force. Interlimb asymmetry was very much present in all types of prosthesis tested but is less pronounced in the flexible keel prostheses. In the latter, the asymmetry may be associated with the force-time history modulation rather than its magnitude alone. Generally, the impulses better describe interlimb asymmetry and the forces allow a greater discrimination between prosthetic foot types.

Adolescent↗
PubMed1992

Six vs twelve cycles for complete responders to chemotherapy in small cell lung cancer: definitive results of a randomized clinical trial. The "Petites Cellules" Group.

Of 320 patients with small cell lung cancer (SCLC) entered into a clinical trial of chemotherapy between January 1983 and September 1985, 106 patients achieved a complete response. The induction chemotherapy used was lomustine 60 mg.m-2 p.o., cyclophosphamide 1 g.m-2 i.v., doxorubicin 45 mg.m-2 i.v. and etoposide 150 mg.m-2 i.v., every four weeks. Lomustine was only given for the first three cycles. Seventy nine of the 106 patients still in complete response after six chemotherapy cycles were subsequently randomized to receive either six more cycles or no more treatment until relapse. In this group of 79 patients, a difference was shown from the time of inclusion between the 51 patients with limited disease and the 28 patients with disseminated disease, with overall median survivals of 395 and 165 days, respectively, (p = 0.0002). No difference was shown between the two treatment groups: the median survival was 332 days from the time of second randomization with a two year survival rate of 28% for the patients randomized to receive six more cycles and 246 days and 22% for those randomized to receive no more treatment (add 147 days to obtain overall median survival). Continuing chemotherapy for more than six cycles to patients in complete response did not improve survival.

Aged↗
PubMed1992

[Malignant primary intrathoracic histiocytofibroma].

Malignant primary intrathoracic fibrous histiocytoma (MFH) is a rare tumour: since it was first described in 1979, hardly more than 80 cases have been published. We present a large MFH which had started in the pleura and was intrathoracic. The tumour was typical, being comprised of malignant fibroblastic and histiocytoid cells in storiform arrangement. It was revealed by spinal bone metastases which multiplied over the whole skeleton in spite of chemotherapy. The patient died of cerebral metastasis developed 8 months after the onset of the disease. The cases found in the literature are gathered together and commented.

Bone Neoplasms↗
PubMed1991

The descriptive epidemiology of hysterectomy, Province of Quebec, 1981-1988.

This study reports the descriptive epidemiology of hysterectomy in the Province of Quebec, Canada, from 1981 to 1988. Data on hysterectomies (n = 150,849) among women 15 years and older were obtained from MED-ECHO, a computerized database of hospital discharge summaries. Hysterectomy rates were established, with denominators consisting of the estimated female populations with a uterus. From 1981 to 1988, the age-adjusted rate for hysterectomy declined from 100.4 to 67.4 per 10,000 women with a uterus. Curves representing age-specific rates of hysterectomy revealed a consistent bimodal pattern over time, a first peak occurring in women aged 40 to 44 years, and a second in women aged 65 to 69. Hysterectomy rates for elective conditions such as leiomyoma, endometriosis, disorders of menstruation, and prolapse decreased consistently over time. The proportion of women who had a hysterectomy and simultaneous bilateral oophorectomy declined from 35% in 1981 to 30% in 1988. Despite the substantial decline in the frequency of hysterectomy over the 8-year period, at rates prevailing in 1988, three of ten women would have had a hysterectomy by the age of 60.

Adolescent↗
PubMed1991

[Primary bronchial cancer in subjects aged 40 or younger].

Between 1985 and 1989, 395 patients with primary lung cancer were treated at the Percy military teaching hospital, Paris. Among them were 16 patients (4%) aged between 29 and 40 years (mean: 34 years) and smokers (mean cumulative tobacco consumption 24 P.A.). Six of these (37%) had lung parenchyma dystrophy with bilateral apical bullae of emphysema, 1 had a clean cavity left by a previous lung abscess and 1 had microcytic fibrosis resulting from histiocytosis X of the lungs and bones. In all cases cancer had developed in contact with bullous lesions or sequelae. Cancer was discovered during radiological mass screening in 6 cases (37.5%), on the finding of systemic or thoracic symptoms in 5 cases and because of a distant metastasis in 5 other cases. Pathological examination revealed an adenocarcinoma in 8 out of 16 patients and only one small-cell carcinoma. Nearly two-thirds of the patients had reached an advanced stage: 3 were in stage III A, 1 in stage III B and 6 in stage IV. Eight patients underwent curative surgery (7 lobectomies, 1 pneumonectomy). Survival was known with precision in 14 patients: 8 died after a mean follow-up of 15 months (range: 3 and 31 months); 3 were alive with an active cancer and 4 are still alive in complete remission after curative surgery. Six published studies totalling 387 cases are concordant in demonstrating that primary lung cancer is severe in adults below 40 years of age and that surgery is useful in such cases, even with N2 lymph node involvement.

Adenocarcinoma↗
PubMed1991

[Eosinophilic lung disease caused by filariasis. Apropos of a case].

A 23-year-old male Pondichery native consulted for vesperal dispnoea. The main abnormalities detected were blood and alveolar eosinophilia and bilateral micronodular lesions at radiography. The parasitic origin of these symptoms was suspected, then confirmed by serological tests for filaria. The outcome was favourable after antiparasitic therapy. The histopathological, clinical and evolutionary features of pulmonary eosinophilic filiariasis are described, with emphasis on the treatment and on follow-up laboratory tests.

Adult↗
PubMed1991

[Wegener's granulomatosis. Therapeutic indications and follow-up course. Apropos of 5 cases].

Five cases of Wegener's granulomatosis treated with cyclophosphamide (CPM) and prednisolone are reported. Four of these patients received intermittent intravenous boluses of cyclophosphamide with the aim of improving the prognosis and renal function and at the same time to attenuate any haematological or vesical toxicity of CPM. The initial response to treatment by boluses of CPM was favourable in all cases but three patients presented with relapses, which were sometimes repeated and boluses of CPM did not enable a remission to be maintained at the time. Recourse to continuous oral therapy in place of bolus therapy proved viable for the maintenance of remission in two cases. The bladder and haematological tolerance to the bolus was satisfactory but an episode of severe neutropenia led to an adaptation of the dose of CPM. The intermittent administration above all the low cumulative dose of CPM obtained with the boluses will explain the better vesical and haematological tolerance observed depending on the capacity to maintain a prolonged remission. The indications for boluses of CPM in the treatment of Wegener's granulomatosis remain uncertain and do not seem to be totally without inconvenience.

Administration, Oral↗
PubMed1990

Sensitivity and specificity of computed tomography for the detection of adrenal metastatic lesions among 91 autopsied lung cancer patients.

The ability of computed tomography (CT) to detect metastatic lesions in adrenal glands was evaluated on 91 autopsied lung cancer patients who died in 11 hospitals in the eastern United States and Canada from January 1983 to February 1988. Abdominal CT scans within 90 days of death were reviewed twice by two radiologists blinded to the autopsy diagnosis. The likelihood of metastatic spread in each adrenal gland was scored on a five-level scale. Histopathologic findings at autopsy were used to establish the presence or absence of metastases. The sensitivity of CT was low. Among 53 adrenal glands with proven metastatic lesions, the proportion with positive CT scans varied from 20.0% to 41.1%, according to the positivity threshold. In contrast, the specificity of CT was high, even at relaxed positivity thresholds, from 84.5% to 99.4%. The relatively low sensitivity of CT to detect adrenal metastatic lesions is explained to a large extent by the lack of substantial structural changes in many adrenal glands found to have metastases at autopsy. With a strongly positive CT scan, the probability of an adrenal metastatic lesion is high, and confirmatory adrenal biopsy may not be needed in patients with adenocarcinoma and large cell carcinoma.

Adenocarcinoma↗
PubMed1990

Failure of the perioperative PCV neoadjuvant polychemotherapy in resectable bronchogenic non-small cell carcinoma. Results from a randomized phase II trial.

In 1985, the authors began a phase II study to assess the PCV perioperative polychemotherapy (cisplatin 100 mg/m2, cyclophosphamide 600 mg/m2, vindesine 3 mg/m2) in patients with resectable bronchogenic non-small cell carcinoma. Patients were randomized to receive either two preoperative courses of PCV chemotherapy, surgery, and two postoperative courses of PCV chemotherapy (PCV group) or immediate surgery (surgery group). A staging procedure using the CT scan was performed before randomization and, additionally, before surgery in the PCV group. There were 26 randomized patients, 13 in each group. In the PCV group, 11 patients agreed to receive the two preoperative courses of chemotherapy. A response was observed in five patients (45%), and a progression was observed in four patients (36%) leading to a cancellation of surgery in two of them. Postoperative care was the same for each group. Although no death could be related to chemotherapy, it was decided to stop entering new patients into this trial because of the rate of preoperative progression in the PCV group.

Adult↗