Search PubMed⌕ Search

Biomedical subjects

B Richard

Publications and source records attributed to B Richard.

At least 37 records · Page 2Linked to original sources
PubMed2001

An in vitro study of the pH-lowering potential of salivary lactobacilli associated with dental caries.

AIMS: Lactobacilli are known to produce acids from sucrose or glucose. This acid production can cause a drop in pH which is sufficiently significant to demineralize the hard tissues of the teeth. Some authors have demonstrated the benefits of substituting sorbitol or xylitol for sucrose. The aim of this work was to study the acid production of salivary lactobacilli with one test sugar (glucose) and two polyols (sorbitol and xylitol). METHODS AND RESULTS: The pH-lowering potential of three strains of oral lactobacilli was recorded with glucose or one of the polyols at three different concentrations. The results showed that polyols were broken down by certain strains of lactobacilli. When this degradation took place, the pH dropped to values sufficiently low to demineralize the hard tissues of the teeth. CONCLUSIONS: Further studies must be carried out on the metabolism of polyols before encouraging their widespread substitution for sucrose.

Child↗
PubMed2001

Leprosy affects the tibial nerves diffusely from the middle of the thigh to the sole of the foot, including skip lesions.

This study investigated where leprosy affects the posterior tibial nerve and whether neurolysis is beneficial. Nine patients with bilateral posterior tibial leprous neuropathy with no sensorimotor recovery were studied. Preoperative sensory-muscle and nerve conduction velocity testing revealed the tarsal tunnel to be the site of a severe lesion in all cases. During surgery, the most proximal site of the nerve lesion was detected by electrically stimulating the spinal roots from the second lumbar nerve to the fourth sacral nerve, evoking efferent mixed nerve compound action potentials that were recorded from the exposed tibial nerve. In all patients, the nerve compound action potentials became normal only proximal to the sciatic nerve bifurcation. Epineuriotomy within these seemingly unaffected segments revealed fibrosis of the interfascicular epineurium. Interfascicular neurolysis was performed on all affected segments. A 2-year follow-up showed an increase in girth of the proximal calf musculature in six of eight patients (the ninth patient had no recordable nerve conduction velocity). It was concluded that (1) leprosy affects the tibial nerves in a scattered way from the sciatic nerve main trunk distally to the exit of the tarsal tunnel; and (2) interfascicular, microsurgical neurolysis is beneficial provided that it is performed on all affected nerve segments.

Action Potentials↗
PubMed2000

[Monoclonal antibody immunotherapy for malignant non-Hodgkin's lymphoma].

THERAPEUTIC OPTIONS: There is a need in the management of non-Hodgkin's lymphoma (NHL) for tumor-targeted therapy. Immunotherapy with monoclonal antibodies can be used to reach this goal. These treatments have however often produced disappointing efficacy and so have not been broadly applicable to patients. MODIFIED MONOCLONAL ANTIBODIES: Technological advances have been used to alter mouse monoclonal antibodies genetically, leading to the development of mouse/human chimeric or humanized antibodies with demonstrated advantages of reduced immunogenicity and enhanced ability to interact with human effector cells. Initial phase I/II trials of monoclonal antibodies for relapse or refractory NHL, especially with chimeric anti-CD20 rituximab, demonstrated encouraging results. FURTHER ASSESSMENT: Randomized trials are now necessary to compare these agents with standard regimens and to determine their optimal use.

Animals↗
PubMed2000

An interactive tool to visualize three-dimensional ultrasound data.

Three-dimensional ultrasound can provide images that are easily understood by people who are not specialists in ultrasonography. However, current visualization methods do not perform very well on 3-D ultrasound data. Apart from some specific cases (obstetrics, cardiology), 3-D ultrasound images have not yet demonstrated major benefits from a clinical point of view. In this article, we introduce an interactive method that allows the user easily to produce 3-D images for each ultrasound examination. It is a two-step method. First, the user roughly segments the data by drawing three boundary curves in perpendicular planes. A ray-casting algorithm then automatically retrieves the details of the objects. Because it can be used routinely, this tool should help to evaluate the potential of 3-D ultrasonography.

Algorithms↗
PubMed2000

Use of Van Nes rotationplasty to manage a burnt knee.

An 11 month old child sustained a deep burn injury to the left knee causing total destruction and sequestration of the knee epiphyses. The ensuing leg length discrepancy with growth was managed by a Van Nes rotationplasty at age four with a good immediate functional result using a below 'knee' prosthesis and the prospect of continuing ambulation as he grows. The surgical options for managing this problem are discussed.

Artificial Limbs↗
PubMed2000

Polymorphonuclear leukocyte-elastase in Crohn's disease: correlation with 99mtechnetium hexamethyl propylene amine oxime leukocyte scintigraphy.

In Crohn's disease (CD), labeled leukocyte scintigraphy results are highly correlated with radioendoscopic findings and the degree of histologic inflammation. We evaluated the correlation between leukocyte activity measured by two complementary methods. polymorphonuclear leukocyte (PMN)-elastase concentration and leukocyte scintigraphy. In 20 patients with CD, labeled leukocytes, 99m technetium hexamethyl propylene amine oxime (99mTc-HMPAO) scintigraphy, and PMN-elastase concentration were evaluated on the same day. A good correlation was found between PMN-elastase concentrations and the scintigraphic scores (p = 0.005; rs = 0.60; 95% CI, 0.20-0.83). Scintigraphy results were significantly correlated with CD activity index (p = 0.023, rs = 0.50). In four patients, scintigraphic scores and clinical disease activity were not consistent due to the state of PMN leukocyte activation, measured by elastase concentration. In CD, PMN-elastase can provide information about the degree of activation of PMN leukocytes and may explain discrepancy between clinical and scintigraphic indexes.

Adult↗
PubMed2000

Phase II study of 3-hour infusion of high dose paclitaxel in refractory and relapsed aggressive non-Hodgkin's lymphomas. Groupe d'Etude des Lymphomes de l'Adulte.

BACKGROUND AND OBJECTIVE: The first clinical studies of paclitaxel as a single agent for the treatment of relapsed or refractory low or intermediate grade non-Hodgkin's lymphomas (NHL) yielded controversial results regarding the response rates observed, mainly related to the dose and schedule of administration used. To obtain additional data concerning the efficacy and toxicity of paclitaxel in intermediate and high grade NHL we initiated a phase II study using a 3-hour infusion of high doses of paclitaxel. DESIGN AND METHODS: The eligibility criteria included patients with relapsed or refractory aggressive NHL, a performance status < or = 2 (WHO index), a platelet count > or = 100,000/microL, a neutrophil count > or = 2,000/microL, measurable disease, and adequate hepatic function. Patients were excluded if they were infected with HIV, had a left ventricular ejection fraction < 50%, or prior peripheral neuropathy. Paclitaxel was administered as a 3-hour infusion at a dose of 250 mg/m2 every 3 weeks for a maximum of 6 courses. RESULTS: Of 45 eligible patients, 42 received a total 73 courses of paclitaxel. Forty patients were assessable for response (89%), and 42 for toxicity (93%). Six patients (15%) achieved a partial (n = 4) or a complete remission (n = 2). Responses were observed in intermediate grade (n = 4) as well as in high grade lymphoma (n = 2). The main factor influencing the response to paclitaxel was the median duration of response to previous chemotherapy regimens which was 3 times longer in patients who responded to paclitaxel (16.3 months) than in patients who did not respond to paclitaxel (5.2 months) (p<0.05). The most common serious side effects were related to the hematologic toxicity of paclitaxel, and included grade IV granulocytopenia in 20 cases (48%), grade III/IV thrombocytopenia in 14 cases (33%) and grade III-IV anemia in 13 cases (31%). INTERPRETATION AND CONCLUSIONS: Despite frequent manageable hematologic toxicity, paclitaxel is usually well tolerated at a dose of 250 mg/m2 given by a 3-hour infusion. However, the clinical efficiency as a single therapy seems modest in relapsed or refractory aggressive lymphoma.

Adolescent↗
PubMed2000

[Ovarian endometriosis cyst with iodine 131 uptake : first case of false positive in the follow up for differentiated thyroid carcinoma].

A whole body scan is performed after a radioiodine treatment in patients with differentiated thyroid carcinoma. This scan is useful coupled with thyroglobulin level for the patient's management. When unusual uptake is found, investigations have to be done to eliminate thyroid metastasis. A 28-year old woman underwent a total thyroidectomy for micro papillary carcinoma. Two years and a half after, ultrasonography of the neck showed a small lymph node in homolateral side of carcinoma. It was decided to begin treatment with iodine 131. The post-therapeutic scan showed an abnormal pelvic uptake. IRM found no osseous abnormality but an ovarian lesion. After surgery, histological diagnosis was an endometriosis cyst without thyroid or tumoral cells. Abdominal ou pelvic iodine false positive are rare. Ovarian cysts may be the cause of false positive radioiodine uptake. Endometriosis cyst was not previously described and the mecanism of iodine uptake is not clear.

Adult↗
PubMed1999

Unilateral neck exploration under local anesthesia: the approach of choice for asymptomatic primary hyperparathyroidism.

BACKGROUND: Conventional parathyroidectomy involves a bilateral neck exploration with the patient under general anesthesia with a thorough search for all parathyroid tissue. The purpose of this study was to assess the efficacy and safety of unilateral neck exploration under local anesthesia in patients with asymptomatic primary hyperparathyroidism (first-degree hyperparathyroidism). METHODS: Of 679 patients who underwent parathyroidectomy for first-degree hyperparathyroidism from July 1989 to June 1997, 230 asymptomatic patients underwent unilateral neck exploration under local anesthesia. Selection criteria for this approach included the successful identification of a solitary parathyroid adenoma on preoperative imaging, no thyroid disease, and no family history of multiple endocrine neoplasia. Intact parathyroid hormone levels were monitored during the operation. RESULTS: Total serum calcium levels were normal in 220 patients (96%) 3 to 6 months after surgery. Ten patients (4%) experienced persistent hypercalcemia, 8 of whom had multiple gland disease and 2 of whom had false-positive imaging. Two of these patients underwent bilateral neck exploration under general anesthesia and were cured, although 8 patients remained asymptomatic and were followed up non-operatively. The mean operating time was 30 minutes (range, 12-65 minutes). There were two complications (0.87%) including one wound hematoma and one transient recurrent laryngeal nerve palsy. CONCLUSIONS: Unilateral neck exploration under local anesthesia is an efficacious and safe approach to the treatment of first-degree hyperparathyroidism and should be considered in all patients with asymptomatic disease.

Adenoma↗
PubMed1999

Test object for measurement of section thickness at US.

A simple phantom was used to test the ultrasound beam profile in the elevation direction (perpendicular to the scanning plane). Based on the inclined plane method, the phantom allowed direct clear display of the section thickness over the whole exploration depth on a single standard ultrasonographic image. This was demonstrated with one- and one and one-half-dimensional arrays. The results showed the efficiency of electronic focusing in the elevation plane associated with one and one-half-dimensional arrays.

Humans↗
PubMed1999

The stapedial reflex as a topographical marker of proximal involvement of the facial nerve in leprosy. A pilot study.

This study aimed to determine the parameters necessary for a study of stapedial reflexes in leprosy patients to ascertain if the facial nerve is involved more proximally than the stylomastoid foramen. It involved leprosy patients with and without facial nerve involvement and non-leprosy controls. Clinical examination of the patients' ears, a tympanogram and audiogram to exclude conductive and sensorineural deafness, followed by the measurement of a stapedial reflex and the acoustic reflex threshold, were carried out. The number of absent reflexes and the acoustic reflex thresholds did not differ between the three groups of subjects. A definitive study would be logistically impossible. Suggestions are made as to more exact patient selection in order to demonstrate any stapedial reflex changes due to leprosy. The findings of this study do not suggest that facial nerve pathology extends proximally to the stylomastoid foramen, unless such proximal involvement is subclinical to the detection methods used.

Adolescent↗
PubMed1998

[Imaging of adrenal glands].

The technical choice in imaging the adrenal gland will depend on several factors discussed in the review. CT and MRI are achieving increasingly high accuracy in the investigation of patients suspected to present adrenal pathology. Scintigraphy evaluates functional patterns of both adrenal cortex and medulla, depending on the radiopharmaceutical that is used. Non invasive characterization of adrenal lesions is very important in cases of incidental discovery of adrenal masses. This review concentrates on new techniques for evaluating the incidentally discovered adrenal masses and differentiating between adrenal adenomas and metastases.

Adenoma↗
PubMed1998

Technetium Tc 99m hexamethyl propylene amine oxine leukocyte scintigraphy in patients with ulcerative colitis: correlation with clinical, biologic, endoscopic, and pathologic intensity, and local release of interleukin 8.

BACKGROUND: Technetium Tc 99m hexamethyl propylene amine oxine (99mTc-HMPAO) has been used to radiolabel leukocytes with promising results for its clinical use in inflammatory bowel disease. During active ulcerative colitis, colonoscopy is indicated to determine the extent and the intensity of the disease for proper management. The aim of this prospective study was to determine whether 99mTc-HMPAO-labeled leukocyte scintigraphy can give information similar to that obtained with colonoscopy during acute attacks of ulcerative colitis. METHODS: Thirty-three consecutive patients with 50 acute episodes of ulcerative colitis underwent 99mTc-HMPAO scintigraphy and colonoscopy with biopsies. Scintigraphic determination of disease extent and intensity were compared with those obtained by colonoscopy with biopsies and clinicobiologic markers. RESULTS: The scintigraphic index of disease intensity was correlated with endoscopic index, Truelove index, biologic markers, and local release of interleukin-8. The extent measured by scintigraphy was well correlated to the endoscopic and histologic extent. CONCLUSIONS: 99mTc-HMPAO scintigraphy accurately determines the extent and the intensity of acute ulcerative colitis lesions. This noninvasive method can specify the extent and the intensity of an acute attack in patients with previously known ulcerative colitis.

Adult↗
PubMed1998

Experimental evaluation of nonlinearities of small-sized insertable gradient coils.

A phase imaging technique is proposed to map out and quantify gradient nonlinearities of small-sized insertable gradient coils, assuming the whole-body system gradients are highly linear in the domain of interest. The theory is developed and simple equations are derived to allow quantification. It is applied to a 4-loop 18-cm diameter cylindrical gradient coil of optimal design. Experimental gradient nonlinearity maps are obtained for different fields of view. Gradient non-linearities are quantified locally and in regions of interest, showing close agreement with model data.

Algorithms↗
PubMed1998

C-reactive protein serum level is a valuable and simple prognostic marker in non Hodgkin's lymphoma.

Interleukin-6 plays a central role in normal B-cell maturation and in proliferation of some B-cell malignancies including multiple myeloma and some non Hodgkin's lymphomas (NHL). Furthermore, this cytokine also plays a major role in acute phase response by mediating synthesis of acute phase proteins such as C-reactive protein (CRP). In order to evaluate the exact role of CRP serum level as a simple prognostic factor, we analyzed CRP and IL-6 serum levels in 39 patients with NHL. Eleven patients had low grade NHL, 15 intermediate grade NHL, and 13 high grade NHL. Thirty percent of the patients presented detectable IL-6 serum levels (mean+/-SD: 33.6+/-95.2 U/ml, range: 0 to 500). Increased serum CRP levels were found in 42% of the patients with a mean of 29.2+/-41.97 mg/l] (range: 0 to 129). Thirty seven patients were studied for both markers. Three groups of patients were determined. One with low IL-6 and CRP serum levels (N=21), a second with high level of both markers (N=10), and the third with high serum CRP levels alone (N = 5). Only one patient had high level of serum IL-6 with no detectable CRP. The correlation of serum IL-6 and CRP levels with patient survival was investigated. Median survival in the group with low IL-6 level was not reached. 67% of patients of this group were still alive at 32 months from diagnosis. The group of patients with detectable IL-6 had a median of survival of 12 months (p<0.025). The survival of patients with a CRP<10 mg/l was not reached. 75% of patients survive at 32 months from diagnosis, whereas the group with higher CRP level reached a median survival at 8.5 months (p<0.009). As expected, on univariate analysis, there is a significant relationship between CRP and IL-6 levels (p<0.00017), and CRP levels and B symptoms (p<0.001). Furthermore there is a significant relationship between CRP and LDH levels (p<0.042).These results indicated that CRP may be considered as a valuable and easy prognostic biomarker of NHL.

Biomarkers, Tumor↗
PubMed1997

Technetium-99m sestamibi scintigraphy, magnetic resonance imaging and venous blood sampling in persistent and recurrent hyperparathyroidism.

Surgical treatment for primary hyperparathyroidism (HPT) is effective in 90% of cases. Recurrent or persistent HPT occurs in 10% of cases. Parathyroid imaging is indicated to confirm and locate an abnormal gland before reoperation. The aim of this study was to evaluate whether the combination of 99Tcm sestamibi scintigraphy, MRI and venous blood sampling (VBS) improved the overall sensitivity for abnormal parathyroid gland detection. 18 patients with recurrent or persistent HPT underwent sestamibi scintigraphy (n = 18), MRI (T1 weighted and STIR sequences) (n = 18) and venous blood sampling (n = 12) at different sites (internal jugular veins, innominate veins, and superior vena cava). All patients underwent surgical exploration. MRI yielded positive results in 15 cases (sensitivity 88%), sestamibi scintigraphy in 14 cases (83%) and VBS in 10 cases out of 12 (83%). Combined results of MRI, sestamibi and VBS yielded positive results in 16 cases (94%). The combination of MRI, sestamibi scintigraphy and VBS improved accuracy in detecting abnormal parathyroid glands before reoperation.

Adenoma↗