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Biomedical subjects

C Martin

Publications and source records attributed to C Martin.

At least 577 records · Page 32Linked to original sources
PubMed1995

[Penetration of ceftriaxone (1 or 2 gr intravenous) into mediastinal and cardiac tissues in man].

Ceftriaxone penetration into heart tissues (valves, myocardium, auricles and pericardium) and mediastinal tissues (fat and sternal bone) was evaluated after two regimens of ceftriaxone administration. Ten patients were given 1,000 g intravenously of ceftriaxone 30 min. before anesthesia. Ten other patients received the same dose and then a second 1,000 mg dose at the time of initiation of cardiopulmonary bypass. Similar and very satisfactory ceftriaxone tissue penetrations were observed in both groups. However, for some patients in the two groups and mainly in the sternal bone at the time of thorax closure, ceftriaxone levels in tissues were less than the MICs for some potential pathogens (Methicillin susceptible Staphylococcus aureus and Staphylococcus epidermidis). During the different steps of the surgical procedures all patients in both groups had tissue levels greater than the MICs for Gram negative aerobic bacilli, except for Pseudomonas spp.

Adult↗
PubMed1995

[Widened retrolabyrinthine approach. Value in the surgery of acoustic neuroma with attempt of hearing preservation].

The retrolabyrinthine approach was described several years ago, however its use was restricted to functional surgery of the cerebellopontine angle. Its detractors reproach its narrowness. But a large approach to the cerbellopontine angle can be performed after an extended exposure of the posterior and middle fossa dura, and section of the endolymphatic sac. This approach was used in 5 cases of acoustic neurinomas stage I and II, with normal hearing. Hearing preservation was obtained in 2 cases. We had deafness in 2 cases who had extensive tumor in the bottom of the internal auditory canal.

Hearing Disorders↗
PubMed1995

Biomechanical effects of different surgical procedures on the extensor mechanism of the patellofemoral joint.

Loadbearing stresses in the patellofemoral joint were studied at different degrees of flexion before and after various surgical techniques recommended to treat knee disorders. Surgical procedures intended to reduce the intensity of stress were analyzed experimentally. The study was done using different experimental methods on whole knee specimens from fresh human cadavers that were not treated with formaldehyde. The results indicate that the most predictable procedure for increasing surface area and decreasing patellar stress is a combined procedure of anterior displacement of the anterior tibial tubercle by 1 cm while displacing it 0.5 to 1 cm medially.

Biomechanical Phenomena↗
PubMed1995

Sensory receptors in the anterior uvea of the cat's eye. An in vitro study.

PURPOSE: To identify electrophysiologically the functional types of sensory fibers innervating the iris and the ciliary body of the cat's eye. METHODS: The uveal tract tract of cat's eye was excised and placed in a superfusion chamber. Recordings were made from single afferent units of ciliary nerve branches responding to mechanical stimulation of the iridal surface, the ciliary body, and the choroid with a nylon filament or a glass rod. Chemical sensitivity was explored by applying acetic acid, hypertonic NaCl, and bradykinin. Warm (60 degrees C) and cold (4 degrees C) saline and a servocontrolled thermode were used for thermal stimulation. RESULTS: Thirty per cent of the studied population of sensory units (n = 95) were spontaneously active when the recording was started. Approximately 30% of the fibers conducted in the lowest range of the A-delta group; the remaining 70% were C fibers. Sustained mechanical stimulation of the receptive area elicited a tonic response in approximately 60% of the units, and a phasic response in the remaining 40%. Exposure of the receptive field of mechanosensitive fibers to 600 mM NaCl evoked a long-lasting discharge in 50% of the units; application of 1 to 10 mM acetic acid elicited a short discharge in 30% of the fibers, often followed by inactivation. Bradykinin (1 to 100 microMs) produced a long-lasting response in almost 50% of the units. Warming the receptive field recruited 20% of the explored units, whereas 17% were activated by low temperature. CONCLUSIONS: Two main functional types of sensory fibers innervating the iris and the ciliary body were distinguished: (1) mechanoreceptors, corresponding to afferent units sensitive only to mechanical stimuli were generally silent at rest, had relatively higher force thresholds, and discharged phasically in response to long-lasting mechanical stimulation; (2) polymodal nociceptors, which were activated by mechanical as well as by chemical and/or thermal stimuli, usually displayed spontaneous activity, had lower force thresholds, and fired tonically upon sustained mechanical stimulation.

Acetates↗
PubMed1995

["Optimized" retrolabyrinthine approach. Contribution of endoscopy of the cerebellopontine angle].

Retrolabyrinthic access was described long ago but was often found to narrow and progressively abandoned in favour of the retrosigmoid route. Certain modification in the initial technique, notably in wider dissection of the dura-mater of the sigmoid sinus and sometimes section of the endolymphatic canal provides a larger access to the ponto-cerebellous angle. A rigid 0 degree or 30 degrees endoscope can be introduced. In order to evaluate this method, we examined surgical specimens and subjects operated via retrolabyrinthic access for a neurinoma of the acoustic nerve in an attempt to preserve auditive function or for suspected vessel-nerve conflict. Our findings demonstrated that the retrolabyrinthic route allows direct access to the ponto-cerebellous angle doser to the vascular and nervous structures than the retro-sigmoid route and also provides remarkable endoscopic vision of the angle and its elements. This route is particularly interesting for surgery of acoustic neurinomas when attempting to preserve the auditive functions, for diagnosis and treatment of vessel-nerve conflicts, and to a lesser extent for vestibular neurotomy or for evaluating certain diseases difficult to diagnosis in the posterior cranial fossa.

Cerebellar Neoplasms↗
PubMed1995

[Comparative study of recovery in neurosurgery after continuous perfusion of etomidate or propofol].

Two groups of patients were studied. Patients in group 1 were given 0.3 mg.kg-1 IV etomidate, 5 micrograms.kg-1 fentanyl and 0.6 mg.kg-1 atracurium for induction. Maintenance was obtained using continuous infusion of etomidate and fentanyl. Patients in group 2 were given propofol for induction and maintenance. Recovery was assessed with three parameters: time to recovery of spontaneous ventilation (SV), time to obey oral order (OO), and time to obey written order (WO). Time to OO and WO were significantly shorter in group 2.

Adult↗
PubMed1995

[Use of the Bactec TB 460 method for the bacteriological diagnosis of tuberculosis. Results of a multicenter study].

Isolation of Mycobacteria on Loewenstein-Jensen medium lasts many weeks. The use of Radiometric method (Bactec TB 460) reduces the delays. Results of 79,064 cultures are reported from a multicentric study associating 16 laboratories. The average was 4.8% of positivity and 2.51% of contamination. The comparison of the results with conventional method previously obtained shows that radiometric method is more sensitive and contaminations are less numerous. Concerning hemocultures the Bactec method is very usefull. Among 11,277 tests performed 907 were positive (8.04%). Mycobacterium avium was identified in 89% of the cases. Identification test utilizes Biochemical and NAP tests, but also more and more Nucleic probes. The antibiotic sensitivity is performed in five days. The mean delay of analysis is about 25 days, lessening by half the conventional method delays. Nevertheless, Bactec method has the following inconveniences: syringe inoculation, use of radiolabelled products, expensive cost.

Anti-Bacterial Agents↗
PubMed1995

[Adenoviruses from stool samples in hospital units. Comparison with main pathogens in gastroenteritis (rotavirus, Campylobacter, Salmonella)].

During a six-years period (1988-1993), a total of 14,644 stool samples from in-patients of Limoges University Hospital were examined for the presence of principal enteric pathogens, such as adenovirus, rotavirus, Campylobacter, Salmonella, Shigella and others. Stools were processed for identification of bacteria by standard methods and viruses were detected in fecal specimens using antigen detection methods: ELISA (Enzyme Linked Immunosorbent Assay) and latex agglutination test. The decreasing rates of presence of enteric agents were respectively 6% for rotavirus, 3.2% for Salmonella, 2% for adenovirus, 1.6% for Campylobacter and 0.2% for Shigella, but according to the lack of sensibility of latex agglutination test, adenovirus prevalence was probably underestimated. Concerning the distribution of enteric pathogens throughout the year, our data demonstrate that rotavirus were rather shed during the months from January to April, adenovirus between April and August, Campylobacter during summer and Salmonella from July to October. The two thirds of Campylobacter and rotavirus infections and the half of adenovirus and Salmonella infections were identified during the ten first years of life. The highest prevalence occurs before 5 years old, during the 2nd year of life for adenovirus (4.4%) and rotavirus (22.3%) and during the 3rd year of life for Campylobacter (6.84%) and Salmonella (8.6%).

Adenovirus Infections, Human↗
PubMed1995

[Value of media containing chromogenic substrates for the identification and the listing of urinary bacteria].

Performance in terms of enumeration, growth and identification with a new culture medium (CPS ID2, bioMérieux) was evaluated using 405 urine samples and 244 collection strains. The CPS ID2 medium contains chromogenic substrates enabling the detection of 4 bacterial enzymes which leads to the identification of colonies: Escherichia coli, Proteus mirabilis, Proteus-Morganella-Providencia and enterococci. No discrepancies in the enumeration were observed with the collected strains and urine samples. Sensibility and specificity of the identification of Proteae taxa (TDA +) and enterococcal taxa (Gram positive cocci and beta-glucosidase +) was 100% using urine samples and 95.1% of E. coli strains (beta-glucuronidase +, indole +) are detected. Routine use of this new medium for the bacterial examination of urine is satisfactory and an ultra-violet lamp is no longer required for reading as was the case previously with media containing fluorogenic substrates.

Anti-Bacterial Agents↗
PubMed1994

[Iatrogenic and traumatic cerebro-meningeal infections].

Nosocomial cerebro-meningeal infections have a severe prognosis and are increasing infrequence. Main causes are neurosurgical procedures, ventriculostomies, head trauma and rarely peridural anaesthesia and lumbar punctures. The diagnosis is usually difficult because of the poor specificity of the clinical and laboratory signs. Predominant pathogens are gram-negative bacteria (including Enterobacteriaceae and Pseudomonas) and staphylococci (including Staphylococcus epidermidis). Treatment is based on the use of 3rd generation cephalosporins and sometimes imipenem. An alternative choice is the use of 2nd generation quinolones. If staphylococci are suspected, vancomycin, alone or in combination is prescribed.

Craniocerebral Trauma↗
PubMed1994

Effects of neutron-gamma irradiation on striatal D1 and D2 receptor distribution.

The early effects of neutron irradiation on the striatal D1 and D2 dopaminergic receptor distribution were investigated by quantitative receptor autoradiography. One hour after exposure at the dose of 8.4 Gy, an increase of D1 (+21%) and D2 (+25%) receptor density was observed in the striatum, located at the most anterior levels, containing the richest plexus of dopaminergic fibers afferent from the substantia nigra. Regional differences in changes of D1 and D2 receptor density were observed. This up-regulation could contribute to the development of early radio-induced neuro-vegetative syndrome.

Animals↗
PubMed1994

Trapping of dextran-coated colloids in liposomes by transient binding to aminophospholipid: preparation of ferrosomes.

A procedure is described that allows to increase the efficiency of the loading of liposomes with dextran-stabilized iron oxides (MION). The method produces a preparation of liposomes (REVs) with high iron oxide content as a result of transient binding of oxidized dextran with amino groups of aminophospholipids. Phosphatidylethanolamine (PE)-containing lipid mixtures (PC/DOPE/CH or SM/DOPE/CH, 9:2:9 molar ratio) in organic phase were combined with oxidized MION at pH 8. Liposomes then were obtained by reversed-phase evaporation. Liposomes, 263 +/- 89 nm in diameter, contained up to 11.8 mol Fe/mol phospholipid (encapsulation yield 49%). 10.2% of liposome-associated iron was dissociated from liposomes upon changing the pH to 4.5. When lipid compositions of extracts prepared from liposomes incubated at pH 4.5 and pH 8.0 were compared, an increase of relative PE-content in extracts of liposomes incubated at lowered pH was detected. This indicates a dissociation of imine bonds between aldehydes on the MION surface and PE. The accessibility of liposomal PE for acylation was demonstrated by modification with an activated ester of methoxy poly(ethylene glycol) succinate. Control liposomes, containing no aminophospholipid, or PE-containing liposomes obtained in the presence of non-oxidized MION, were 3.5-5-fold less effective for MION encapsulation and showed extensive aggregation.

Colloids↗
PubMed1994

Flower colour intensity depends on specialized cell shape controlled by a Myb-related transcription factor.

Flower colour is determined primarily by the production of pigments, usually anthocyanins or carotenoids, but the shade and intensity of the colour are often changed by other factors such as vacuolar compounds, pH and metal ions. Pigmentation can also be affected by the shape of epidermal cells, especially those facing prospective pollinators. A conical shape is believed to increase the proportion of incident light that enters the epidermal cells, enhancing light absorption by the floral pigments, and thus the intensity of their colour. We have identified a gene (mixta) that affects the intensity of pigmentation of epidermal cells in Antirrhinum majus petals. The cells of the corolla lobes fail to differentiate into their normal conical form in mixta mutants. We have cloned the mixta gene by transposon tagging; its sequence reveals that it encodes a Myb-related protein that probably participates in the transcriptional control of epidermal cell shape.

Amino Acid Sequence↗
PubMed1994

Gas chromatography applied to the lactulose-mannitol intestinal permeability test.

Intestinal permeability can be modified by various illnesses, trauma and sepsis. Alterations of the intestinal wall can facilitate the diffusion of potentially harmful substances such as endotoxins, as well as bacterial translocation. We describe the validation of a capillary gas chromatographic method for the determination of mannitol and lactulose, used as intestinal permeability probes. The method is linear up to 3 g/l for mannitol and 300 mg/l for lactulose; recovery from overload samples is between 92 to 110%. Intra-assay coefficients of variation (C.V.s) were 2.7 and 6.8% for mannitol and lactulose, respectively, and inter-assay C.V.s were 8.9 and 9.3%. Normal values for 25 healthy subjects (mean +/- S.D.) were 14.5 +/- 3.1% and 0.27 +/- 0.15% for mannitol and lactulose, respectively. The GC method presented is rapid and precise.

Adult↗