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Biomedical subjects

M Bruneau

Publications and source records attributed to M Bruneau.

16 recordsLinked to original sources
PubMed2005

Early surgery for brainstem cavernomas.

BACKGROUND: The purpose was to review our experience with the surgical management of brainstem cavernomas (BSCs) and especially the impact of the surgical timing on the clinical outcome. METHOD: We retrospectively reviewed 22 patients harboring a BSC, who underwent 23 procedures. FINDINGS: Surgery was carried out during the early stage after the last haemorrhage, with a mean delay of 21.6 days (range 4-90 days). Sixteen procedures were performed after a first bleeding event while seven after multiple bleedings. Complete resection was achieved in 19 patients (86.4%). Early after surgery, 12 patients (52.2%) improved neurologically, 5 (21.7%) were stable and 6 (26.1%) worsened. New postoperative deficits were noted after 9 procedures (39.1%). Statistically significant factors for postoperative aggravation were: late surgery (P = 0.046) and multiple bleedings (P = 0.043). No patient operated on within the first 19 days after bleeding did worsen (n = 11), as opposed to 6 out of 12 who did when operated on later. After a mean follow-up of 44.9 months, 20 patients (90.9%) were improved, 1 patient (4.6%) was worse and 1 patient was lost to follow-up (4.6%), after reoperation for rebleeding of a previously completely resected cavernoma. Late morbidity was reduced to 8.6%. The mean Glasgow Outcome Scale (GOS) at the end of the follow-up period was 4.24, compared to a mean preoperative GOS of 3.22 (P<0.001). Complete neurological recovery of motor deficits, sensory disturbances, cranial nerves (CNs), internuclear ophtalmoplegia and cerebellar dysfunction were respectively 41.7%, 38.5%, 52.6%, 60.0% and 58.3%. Among the most affected CNs: CN 3, CN 5 and CN 7 were more prone to completely recover, respectively in 60.0%, 70.0% and 69.2%. CONCLUSIONS: Surgical removal of BSCs is feasible in experienced hands with acceptable morbidity and good outcome. Early surgery and single bleeding were associated with better surgical results.

Adolescent↗
PubMed2005

Experimental and theoretical study of processes leading to steady-state sound in annular thermoacoustic engines.

This paper gives a simplified analytical description of spontaneous generation and finite amplitude saturation of sound in annular thermoacoustic engines, and also provides comparison with experiments. The model includes the precise description of thermoacoustic amplification of sound (induced by interaction between an heterogeneously heated stack of solid plates and resonant gas oscillations), which accounts for the details of the temperature distribution in the whole thermoacoustic device (i.e., which does not only account for the mean temperature gradient along the stack). The saturation of the acoustic wave amplitude is described by taking into account both the reverse influence of high amplitude acoustic field on temperature field, and the dissipation of acoustic energy due to higher harmonics generation and minor losses (vortex generation). From the comparison between simulation results and experiments, it is demonstrated that the dynamical behavior observed in our experimental device is predominantly controlled by the effects of acoustic streaming and acoustically enhanced thermal conductivity tending not only to reduce the externally imposed temperature gradient along the stack, but also to change the shape of the temperature field.

Journal Article↗
PubMed2005

[A new area for radiotherapy with favourable features].

Radiotherapy is a complex medical speciality involving technology research, biology research and clinical research. All these basic researches are performed in order to optimise the management of cancer treatment patients. The aim of the present review is to present radiotherapy as a moving speciality whatever the concerned section. It will be particularly described the new approaches in terms of technology but also clinical developments.

Humans↗
PubMed2001

Anterior cervical interbody fusion with hydroxyapatite graft and plate system.

OBJECT: In cases of spondylosis or spine trauma, cervical interbody grafts are sometimes required after anterior discectomy. To avoid morbidity related to the harvesting of iliac crest bone, numerous materials have been developed such as allografts, methylmethacrylate, biocompatible osteoconductive polymer, and coralline grafts or cages. Some of these materials, however, are inefficient for fusion or are associated with specific complications. Conversely, hydroxyapatite (HA) grafts have numerous advantages. For example, their mechanical properties provide adequate load resistance and their porosity allows infiltration by newly formed bone, leading to complete fusion. The authors studied the results of using HA grafts combined with plating in patients who underwent anterior cervical discectomy. METHODS: Fifty-four patients underwent 68 cervical interbody fusion procedures in which an HA graft and plating were used. Indications for surgery were radiculopathy (caused by soft-disc herniation or spondylosis) in 46 cases, spondylotic myelopathy in two cases, and spinal trauma in six cases. Postoperatively the patients were followed for a mean of 24.6 months. Patients underwent radiography to evaluate fusion, intervertebral disc height, and the degree of lordosis. Clinically, excellent or good results (based on the Odon classification) were demonstrated in 91% of patients who presented with radiculopathy. Complete interbody fusion was achieved in 99% of all cases. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was maintained throughout follow up. Surgery-related morbidity was low; only one patient suffered from a permanent dysphagia. Graft deterioration was observed in 13 cases and two graft fractures occurred but without adversely affecting fusion. There were no cases of graft extrusion. CONCLUSIONS: Hydroxyapatite grafts are very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability is achieved and graft displacement is prevented.

Adult↗
PubMed2000

Acoustic streaming in annular thermoacoustic prime-movers

The theory of acoustic streaming in an annular thermoacoustic prime-mover is developed. It is predicted that above the threshold for traveling wave excitation the device considered (which does not contain any moving parts or externally imposed pressure gradients) produces circulation of fluid. The heat flux carried by this directional mass flow inside the thermoacoustic stack exceeds (or is comparable with) the heat flux associated with the acoustically induced increase of thermal diffusivity of the gas. The effects investigated are important for optimization of the performance of thermoacoustic devices.

Journal Article↗
PubMed1998

Long-term survival after aortic valve replacement for native active infective endocarditis.

BACKGROUND: The objective of this study was to analyse the impact of acute surgery for native aortic valve endocarditis and its influence on the long-term prognosis after surgery. METHODS: A total of 161 patients underwent aortic valve replacement for native active aortic valve endocarditis (NAAVE) during a 29-year period, from 1967 to 1995 (age range: 10 to 72 years; mean 48 +/- 12). The main indication for surgery was progressive congestive heart failure (76%). Other indications were untreatable sepsis (27%), peripheral or central emboli (12%) and, from 1978, echocardiographic evidence of friable, pedunculated vegetations (3%). Streptococcal and staphylococcal infections predominated. Concomitant procedures were performed in 27% of the patients, including mitral and tricuspid valve surgery and coronary bypass procedures. RESULTS: Operative mortality was 8% in the majority of cases caused by heart failure or multi-organ failure. Multivariate logistic regression analysis identified NYHA class IV to be an independent predictor for postoperative death. Long-term survival for discharged patients was 75% at 10 years and 58% at 15 years, with a mortality rate of 3.6%/patient/year. Cox regression analysis identified the year of operation, trivalvular endocarditis and staphylococcal infection as independent predictors of survival. At 10 and 15 years after aortic valve replacement, 91% and 84% of the patients, respectively, were free of recurrent endocarditis. The presence of an abscess cavity at first operation was found to be predictive of recurrent endocarditis. CONCLUSIONS: Valve replacement for NAAVE offers a good chance for a cure and satisfactory long-term survival. Improvements in pre- and per-operative management of the very ill patient, and the use of allograft valves are likely to further improve long-term results. Finally, the presence of staphylococcal endocarditis requires long-term postoperative antibiotic therapy.

Adolescent↗
PubMed1997

Popliteal-to-distal bypass grafts for limb salvage.

From July 1989 to July 1994, a total of 44 popliteal-to-distal artery bypasses were performed in 36 patients (29 men and seven women, mean age 62 +/- 10 years). These procedures accounted for 8.8% of all infrainguinal revascularizations performed during that period. Risk factors included diabetes in 33 patients (92%), smoking in 18 (50%), and coronary artery disease in 15 (42%). Prior to revascularization all patients were at risk of limb loss. Tissue necrosis was present in 31 cases (71%), ulceration in eight cases (18%), and rest pain in five cases (11%). Patency of the femoral and popliteal arteries was confirmed prior to surgery in all cases. Intraoperative percutaneous angioplasty of the superficial femoral artery was performed in three cases. Proximal anastomosis was made to the distal popliteal artery in all cases. A total of 52 distal anastomoses (eight sequential bypasses) were made on the following arteries: posterior tibial artery in 13 cases, anterior tibial artery in eight cases, peroneal artery in six cases, plantar artery in two cases, and dorsalis pedis artery in 21 cases. The greater saphenous vein was used as graft material in 42 cases (95%) and the lesser saphenous vein in two cases (5%). No patient died during hospitalization. Early bypass occlusion occurred in three cases (6.8%) and led to amputation in all cases. Secondary patency and limb salvage rates at 3 years calculated using the actuarial method were 74% and 82% respectively. Bypass thrombosis due to superficial femoral artery deterioration was not observed in any case. The present study indicates that popliteal-to-distal artery bypass is a simple, durable, and low-risk method of lower limb revascularization. Medium-term results are promising and support routine use of popliteal-to-distal artery bypass for limb salvage in patients without significant stenosis of the superficial femoral artery.

Aged↗
PubMed1995

Surgical treatment for acute native aortic valvular infective endocarditis: long-term follow-up.

During the period 1970-1993, 116 patients (63 men, 53 women) with native aortic valvular infective endocarditis were treated surgically. The mean age was 37 years. The main causative organisms were streptococci and staphylococci. Indication for surgery was cardiac failure (70 cases), uncontrolled sepsis (30), peripheral emboli (11) and overwhelming destruction of the aortic valve (five). Hospital and late mortality rates were 8% and 11% respectively. Patients who died in hospital and those who presented a paravalvular leakage had a ring abscess associated with aortic wall destruction. Among 34 patients screened for cerebral septic emboli the condition was confirmed in 15, of whom six were symptom-free. Thus, it is believed that in the presence of root abscess, surgery should be undertaken promptly, regardless of the cardiac status. It is confirmed that cerebral septic emboli should be systematically screened for in the presence of any infective endocarditis.

Acute Disease↗
PubMed1987

Blood chemistry of normal human fetuses at midtrimester of pregnancy.

Thirteen biochemical parameters and five enzymatic activities were determined on sera of 63 normal human fetuses sampled by direct puncture under ultrasound guidance, between the 20th and the 26th wk of gestation, and on their mothers. They were referred to us for various prenatal diagnoses but were well and confirmed healthy at birth. Some parameters were found to be very similar in both groups, mainly creatinine, calcium, creatine kinase, aspartate aminotransferase, and gamma-glutamyl transferase. Some values were significantly higher in the fetuses, such as total bilirubin, direct bilirubin, phosphorus, lactic dehydrogenase and alkaline phosphatase activities, and alpha-fetoprotein. Urea, uric acid, glucose, triglycerides, cholesterol, total protein, and albumin levels were found to be lower in fetuses. These data indicate a slower metabolism in fetuses compared to their mothers, a lower level of energy requirement, and a relative liver immaturity. These normal values of fetal biochemistry will improve our knowledge of physiology and help to determine the specific values of a test in fetal pathology.

Blood Chemical Analysis↗
PubMed1984

[Comparative variations in natriuresis and urinary calcium in patients with hypercalciuric lithiasis treated with thiazide diuretics].

Because of the close relation between sodium (Na) and calcium (Ca) tubular reabsorption, restriction of sodium intake has been proposed in hypercalciuric stone formers. We simultaneously measured urinary concentrations of both ions in 30 recurrent stone formers (19 male, 11 female, mean age 40,8 +/- 10,2 years) with fasting hypercalciuria, before and after reduction of calciuria using long-term thiazide (TZ) treatment associated with moderate restriction of calcium intake, without concomitant Na restriction. No recurrence of stones was observed in this group with a 12 to 49 month follow-up. UCa strongly correlated with UNa in both conditions. However, UCa significantly decreased with TZ (128 +/- 32 vs 73 +/- 26 mumol/kg/day, p less than 0.001), whereas neither UNaV (190 +/- 60 vs 202 +/- 57 mmol/day) nor diuresis significantly varied. We conclude that calciuria can be lowered without reduction in Na intake in hypercalciuric stone formers controlled by thiazide treatment.

Adult↗
PubMed1983

[Urinary excretion of lithogenic substances in hospitalized patients with calcium lithiasis. Physiopathologic meaning and prognostic value].

The urinary excretion of various substances involved in kidney stone formation was evaluated in 67 patients with hypercalciuric lithiasis (HCl), 36 lithiasis patients with normal calciuria (NCl) and 21 controls without urinary stones. All subjects were hospitalized for 3 days and given a calcium, phosphorous and sodium-controlled diet. The 24-hour urine volume was significantly larger in the HCl and NCl groups than in controls. The 24-hour Ca, Na and uric acid excretion was significantly greater in the HCl group than in the NCl and control groups. Oxalate and pyrophosphate excretion was the same in all three groups. Urinary Ca correlated with urinary creatinine in the HCl and control groups, but the slope and ordinate of the regression line were significantly higher in the former group. Similarly, urinary Na correlated with urinary creatinine in the HCl and control groups with a significantly steeper slope in the HCl group. These data are suggestive of abnormalities in the tubular reabsorption of Ca and Na in HCl patients. Finally, there was no correlation between the values obtained and the activity of the disease, as evaluated by the finding of at least 3 urinary stones or one staghorn calculus during the 5 years preceding the study. It is concluded that measurements of Ca, Na, uric acid, creatine, oxalates and phosphates during a stay in hospital provide pathophysiological information but cannot be taken as indices of urolithiasis activity.

Calcium↗
PubMed1982

[In vitro supplementation of pyridoxal phosphate for the optimisation of the determination of the catalytic activity of alanine aminotransferase and aspartate aminotransferase in kidney transplant patients (author's transl)].

Pyridoxal phosphate (PLP) is the coenzyme of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Thus, in vitro supplementation with PLP is important for the optimisation of the determination of catalytic activity of both enzymes. It patients with kidney transplants, stimulation by PLP is very important for ALT activity, which could be affected by plasma PLP deficiency. Furthermore, in this population catalytic activities are more frequently found increased using methods with PLP supplementation than without PLP supplementation (56% and 71% of patients for AST and ALT, respectively). These differences are not related to HBs antigen.

Adolescent↗
PubMedDate not supplied

[Electrophysiologic abnormalities in chronic alcoholism, disclosed by the methods of evoked potentials and Hoffman's reflex. Study of a possible metabolic pathogenesis].

During a preliminary study comparing 5 normal subjects and 5 alcoholics (25 experiments) changes in evoked potentials were found in these patients. There was mainly a reduction in these potentials during the first 100 milleseconds following stimulation. Such a reduction generally means a disorder of the arrival of the influx at the level of the cortex and may be found mainly in peripheral nerve involvement. A complementary study of the H reflex (34 experiments) showed that this reflex was affected in 60% of chronic alcoholics whether or not they had liver cirrhosis. The theory according to which the EEG abnormalities observed may be linked to a metabolic disorder of the amino-acids was not confirmed. The changes of the first 100 milleseconds of the evoked potential associated with the change in Hoffman's reflex are in favour of early peripheral involvement even in alcoholics who do not appear to have any peripheral neuritis. These signs are different from those which are observed in marijuana or psylocybine poisoning where the EEG signs are due to central involvement.

Alcoholism↗