Biomedical subjects

J M Moreau

Publications and source records attributed to J M Moreau.

At least 37 records · Page 2Linked to original sources

PubMed1999

Acute inflammation of the eyelid and cornea in Staphylococcus keratitis in the rabbit.

PURPOSE: The inflammatory response during Staphylococcus keratitis was analyzed biochemically and histologically to determine the source of the neutrophils infiltrating the tear film and cornea. METHODS: Rabbit eyes were swabbed and then examined by slit-lamp microscopy at 0, 5, 10, 15, 20, and 25 hours after intracorneal inoculation with Staphylococcus aureus. Bacterial colony-forming units were quantified in the cornea, eyelid, and acute inflammatory exudate. Myeloperoxidase activity of ocular swabs of acute inflammatory exudate, corneal homogenates, and eyelid homogenates was determined. Gross and microscopic examinations of corneas and eyelids were performed. RESULTS: The colony-forming units per cornea exceeded 10(7) after 10 hours, whereas no bacteria were cultured from the eyelid until 15 hours postinfection. Slit-lamp examination revealed progressive pathology, and the myeloperoxidase activities of ocular swabs, corneas, and eyelids increased markedly by 15 hours postinfection. Corneas showed a wave of neutrophils moving from the tear film toward bacteria in the central corneal stroma and early neutrophil migration from the limbus into the stroma. In the eyelid, neutrophils migrated from the stromal vessels to the tear film. CONCLUSIONS: Staphylococcus keratitis in the rabbit causes acute inflammation in the overlying eyelid. Neutrophils of the acute inflammatory exudate interact with the infected cornea, whereas neutrophils migrating through the cornea from the limbus remained distant from the site of infection.

Acute Disease↗

PubMed1998

No effects of DC and 60-Hz AC magnetic fields on the first mitosis of two species of sea urchin embryos.

The early divisions of sea urchin eggs was used as a model to study the effects of static and of 60 Hz sinusoidal magnetic fields. Two species were used (Sphaerechinus granularis and Paracentrotus lividus). Eggs were fertilized and exposed in two separate coils to the fields (up to 8 mT). Great care was taken to control the temperature of each sample. No difference was found in the time of the first division that could not be attributed to a temperature difference between samples. Comparison is made with other published data on various species.

Animals↗

PubMed1998

Pseudomonas aeruginosa protease IV produces corneal damage and contributes to bacterial virulence.

PURPOSE: A Pseudomonas mutant deficient in protease IV has significantly reduced virulence in experimental keratitis. In the present study, the corneal toxicity of purified protease IV and its ability to augment the virulence of protease-IV-deficient bacteria were analyzed. METHODS: The toxicity of purified protease IV was determined by intrastromally injecting the exoenzyme (20-200 ng) into the cornea. The effects of protease IV on the corneal virulence of the protease-IV-deficient strain, PA103-29::Tn9, were determined by injecting eyes with 1000 CFU of log phase bacteria plus either 200 ng active purified protease IV or 200 ng heat-inactivated protease IV. Changes in ocular disease, determined by slit-lamp examination, were measured at 3, 16, 22, and 27 hours after infection. Colony-forming units per cornea were quantified at 27 hours after infection. RESULTS: Purified protease IV at doses from 50 to 200 ng induced epithelial defects within 3 hours of injection. Injection of 20 ng active protease IV or heat-inactivated protease IV (200 ng) had no effect on ocular tissue. Corneal virulence of the protease-IV-deficient strain was augmented by intrastromal injection with purified protease IV but not with heat-inactivated protease IV (P < or = 0.0001). Neither active nor heat-inactivated protease IV altered the growth of bacteria in the cornea (6 log units; P = 0.81). CONCLUSIONS: The important role of protease IV in corneal virulence was demonstrated by direct toxicity and by its ability to significantly augment the virulence of protease-IV-deficient Pseudomonas.

Animals↗

PubMed1998

Effectiveness of ciprofloxacin-polystyrene sulfonate (PSS), ciprofloxacin and ofloxacin in a Staphylococcus keratitis model.

PURPOSE: Staphylococcus aureus causes severe corneal infections that often result in corneal scarring and blindness. Presently, therapy often involves the use of a fluoroquinolone antibiotic. This study, employing an experimental rabbit model of Staphylococcus keratitis, compared the effectiveness of two commonly prescribed formulations of fluoroquinolones to an experimental formulation, ciprofloxacin with polystyrene sulfonate (ciprofloxacin-PSS). The ciprofloxacin-PSS formulation uses an ion exchange resin to aid in the delivery of drug to the cornea. METHODS: Early (4-9 h postinfection, PI) and late (10-15 h PI) therapies were studied, employing 5 groups: ciprofloxacin-PSS, ciprofloxacin, ofloxacin, PSS vehicle. and untreated. Dosing regimens were: every 30 min, 60 min, or a single drop applied at 9 h PI. Eyes were observed by slit lamp examination (SLE) and bacterial colony forming units (CFU) per cornea were determined. RESULTS: Early phase therapy with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin administered every 30 or 60 min were equally effective (P > or = 0.2880), decreasing CFU per cornea by >5 log. Ciprofloxacin was significantly more active than ciprofloxacin-PSS or ofloxacin (P < or = 0.0410) when applied as a single drop. Late therapy with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin administered every 30 or 60 min resulted in >3 log decrease in CFU per cornea relative to controls (P < or = 0.0001). CONCLUSIONS: Topical treatment of experimental Staphylococcus keratitis with ciprofloxacin-PSS, ciprofloxacin, or ofloxacin was effective. The effectiveness of ciprofloxacin-PSS suggests that improved drug delivery systems employing an ion exchange resin could be useful in an ocular fluoroquinolone formulation.

Animals↗

PubMed1997

Histopathological studies of staphylococcal alpha-toxin: effects on rabbit corneas.

PURPOSE: Previous studies from this laboratory have demonstrated, in a rabbit model of keratitis, a relationship between the corneal virulence of Staphylococcus aureus and the alpha-toxin activity of the infecting bacteria. This study is a histopathological characterization of the action of purified alpha-toxin on corneal tissue. METHODS: Alpha-toxin was purified by isoelectric focusing and intrastromally injected into rabbit corneas (2 micrograms per cornea). A kinetic analysis of toxin effect was performed following injection. Normal corneas and corneas injected with phosphate buffered saline (PBS) or heat-inactivated alpha-toxin in PBS served as controls. Eyes were examined from 0 to 4 h by slit lamp examination (SLE) and scored on the basis of seven ocular parameters. Corneal tissue was removed and examined for histopathological changes. RESULTS: From 0.5 to 4 h post-injection, alpha-toxin injection induced a significant increase in the SLE score relative to untreated eyes or eyes injected with PBS (P < 0.0001). Histolo-pathological examination of corneas one-half h after alpha-toxin injection revealed edema of the central cornea and death of epithelial cells by both necrosis and apoptosis. Later times showed continued edema and loss of apparently normal epithelial cells. Development of polymorphonuclear (PMN) leukocyte infiltration from the tear film into the central cornea and from limbal vessels into the peripheral cornea was observed. CONCLUSIONS: Purified alpha-toxin mediates cell death by necrosis and apoptosis, sloughing of viable corneal epithelial cells, severe corneal edema, and PMN migration into the cornea from both the tear film and limbal vessels. The pathologic changes revealed by histological studies of corneas injected with purified alpha-toxin included death of cells by necrosis and apoptosis as well as overall changes analogous to that seen by SLE of eyes infected with wild-type, but not alpha-toxin-deficient strains of Staphylococcus aureus.

Animals↗

PubMed1997

Specific roles of alpha-toxin and beta-toxin during Staphylococcus aureus corneal infection.

Staphylococcus aureus corneal infection results in extensive inflammation and tissue damage. Our previous studies of bacterial mutants have demonstrated a role for alpha-toxin in corneal virulence. This study analyzes, by genetic rescue experiments, the virulence of mutants affecting alpha-toxin and beta-toxin activity and demonstrates the ocular toxicity of these purified staphylococcal proteins. Three types of isogenic mutants were analyzed: (i) mutants specifically deficient in alpha-toxin (Hla) or beta-toxin (Hlb), (ii) a mutant deficient in both Hla and Hlb, and (iii) a regulatory mutant, deficient in the accessory gene regulator (agr), that produces reduced quantities of multiple exoproteins, including alpha- and beta-toxins. Plasmids coding for Hla and Hlb (pDU1212 and pCU1hlb, respectively) were used to restore toxin activity to mutants specifically deficient in each of these toxins. Either corneas were injected intrastromally with logarithmic-phase S. aureus or purified alpha- or beta-toxins were administered to normal eyes. Ocular pathology was evaluated by slit lamp examination and myeloperoxidase activity of infiltrating polymorphonuclear leukocytes. Corneal homogenates were cultured to determine the CFU per cornea. Eyes infected with the wild-type strain developed significantly greater corneal damage than eyes infected with Agr-, Hlb-, or Hla- strains. Epithelial erosions produced by parent strains were not produced by Agr- or Hla- strains. Hlb+ strains, unlike Hlb- strains, caused scleral edema. Plasmid pDU1212 restored corneal virulence to strain DU1090 (Hla-), and plasmid pCU1hlb restored corneal virulence to strain DU5719 (Hlb-). Application of purified alpha-toxin produced corneal epithelial erosions and iritis, while application of beta-toxin caused scleral inflammation. These studies confirm the role of alpha-toxin as a major virulence factor during S. aureus keratitis and implicate beta-toxin, a mediator of edema, as a lesser contributor to ocular damage.

Animals↗

PubMed1997

Pseudomonas deficient in protease IV has significantly reduced corneal virulence.

PURPOSE: The role of protease IV in the pathogenesis of Pseudomonas aeruginosa keratitis was investigated by comparing a mutant strain completely deficient in protease IV activity with its protease IV activity-producing parent. METHODS: A protease IV-deficient Pseudomonas strain PA103-29::Tn9 was generated by mutagenesis of strain PA103-29, which produces protease IV, through transposon insertion. Protease IV activity was determined by a casein agar assay, zymography, and cleavage of the chromogenic substrate, Chromozym PL. Corneal virulence was evaluated by slit lamp examination and bacterial cultures in both a rabbit intrastromal model and a mouse topical model of keratitis. RESULTS: The protease IV-deficient strain PA103-29::Tn9 had significantly reduced corneal virulence relative to its parent strain PA103-29 in both a rabbit intrastromal model and a mouse topical model of infection. In the rabbit model, ocular damage (slit lamp examination score) mediated by the parent strain was severe at 32 hours after infection, whereas damage mediated by the mutant was minimal at both 32 and 55 hours after infection. This difference in virulence was not a result of differences in growth in vivo, because both strains grew equally. In the mouse model, eyes inoculated with the protease IV-producing parent strain had significant corneal damage as early as 24 hours after infection, whereas the protease IV-deficient mutant strain produced no significant corneal damage during 6 days of infection. CONCLUSIONS: The ability to produce active protease IV was the determining factor in the severity of corneal virulence. Protease IV appears to mediate corneal virulence and should be considered as a target in the development of medications designed to minimize corneal damage during Pseudomonas keratitis.

Animals↗

PubMed1993

Effects of time-varying uniform magnetic fields on natural killer cell activity and antibody response in mice.

Natural Killer cell activity and antibody response were studied in Balb/c mice which were exposed in vivo to uniform pulsed magnetic fields (square-wave, 0.8 Hz, 120 mT maximum field strength, 0.1 s rise-time) for 5 days, 10 h/day. No effects were found in antibody response to sheep red blood cell (SRBC) immunization as assayed by counting the plaque-forming cells (PFC) in the spleens of animals on the sixth day. Following 5-day exposures, the activity of Natural Killer (NK) cells was measured in vitro by challenge with YAC-1 cells, in experiments in which mice were not immunized. An increase of NK cytotoxic activity due to exposure was found which depended on the age of the mice (effect observed above 12 weeks) and on the strength of the applied field (effect observed above 30 mT).

Age Factors↗

PubMed1991

Antibody responses of mice exposed to low-power microwaves under combined, pulse-and-amplitude modulation.

Irradiation by pulsed microwaves (9.4 GHz, 1 microsecond pulses at 1,000/s), both with and without concurrent amplitude modulation (AM) by a sinusoid at discrete frequencies between 14 and 41 MHz, was assessed for effects on the immune system of Balb/C mice. The mice were immunized either by sheep red blood cells (SRBC) or by glutaric-anhydride conjugated bovine serum albumin (GA-BSA), then exposed to the microwaves at a low rms power density (30 microW/cm2; whole-body-averaged SAR approximately 0.015 W/kg). Sham exposure or microwave irradiation took place during each of five contiguous days, 10 h/day. The antibody response was evaluated by the plaque-forming cell assay (SRBC experiment) or by the titration of IgM and IgG antibodies (GA-BSA experiment). In the absence of AM, the pulsed field did not greatly alter immune responsiveness. In contrast, exposure to the field under the combined-modulation condition resulted in significant, AM-frequency-dependent augmentation or weakening of immune responses.

Animals↗

PubMed1991

Post traumatic tracheobronchial lesions. A follow-up study of 47 cases.

This report concerns 47 ruptures of the tracheo-bronchial tree from the tracheal origin to the division of the lobar bronchi (trachea in 30 patients, main bronchus in 11, intermediate or lobar bronchus in 6). The disruption was circumferential in 24 cases and non-circumferential in 23. Injuries resulted from crush or blunt trauma in 35 cases, from seat belt or rope strangulation in 8 cases and in 4 cases, lesions were discovered following the tracheal intubation. The main symptoms were cervico-mediastinal emphysema (39), pneumothorax (31), acute dyspnea (28) and hemoptysis (11). The diagnosis was always confirmed endoscopically. In 8 patients, management of the lesions was delayed for more than 1 week due to misdiagnosis or severe associated injuries. Thirty-eight patients underwent tracheal or bronchial surgical repair associated in 13 cases with a temporary stenting, 4 patients underwent partial or total lung resection, 2 were managed by laser therapy and the 5 others received only medical care and endoscopic survey. Four patients died (8.5%), 2 from bleeding in the bronchial tree from a pulmonary artery tear, 1 from hypertensive pneumothorax under respiratory support and the last from mediastinitis due to delayed diagnosis of an associated oesophageal wound. All 43 other survived in spite of some very critical situations. This experience confirms that technical problems of surgical repair are nowadays overcome and that prognosis of tracheobronchial ruptures mainly depends on the initial control of respiratory failure and complications. Avoiding lethal anoxia or endobronchial damage in the emergency period before referring the patient to the surgeon is essential.

Bronchi↗

PubMed1991

[What may be expected from endorectal ultrasonography and magnetic resonance imaging in the assessment of local extension of cancer of the prostate?].

30 patients presenting with a clinical stage A or B cancer underwent TRUS and MRI with a body coil prior to radical prostatectomy. Imaging and pathology were correlated to assess the limits of TRUS and MRI in pre-operative staging of prostatic carcinoma. Results showed that TRUS and MRI had a sensitivity of 42 and 66% and a specificity of 89 and 94% respectively, for the diagnosis of macroscopic capsular effraction. Seminal vesicle invasion was diagnosed by TRUS with a sensitivity of 16% and a specificity of 81%. With MRI, the sensitivity and the specificity were 85 and 94% if only gross infiltration was considered. Sensitivity dropped to 45% if microscopic invasion was included. We conclude that: (1) postero-lateral venous plexus are more easily delineated by MRI, permitting a more accurate diagnosis of capsular penetration. (2) Seminal vesicle invasion cannot be diagnosed by TRUS as the echostructure of the cancer and the caudal junction of the seminal vesicles and vas deferens are similar. (3) A normal caudal junction on TRUS or a normal bilateral hypersignal of the seminal vesicles on MRI are associated with seminal vesicle invasion in less than 5% of cases. (4) A normal caudal junction on TRUS eliminates false positive cases of MRI related to non tumoral hyposignals of the seminal vesicles.

Aged↗

PubMed1990

The growth of circumferential scars of the major airways from infancy to adulthood.

The factors affecting the development and prognosis of scarred airways in children are presented from a long-term follow-up study of 14 cases of tracheobronchial lesions following either injury or operation. Four children managed by endoluminal treatment developed severe stenosis and required treatment, later as adults, by laser resection in 2 cases and by laryngotracheal plastic enlargement and resection with anastomosis in 1 case each. The follow-up of 7 children managed by plastic procedures showed inconsistent results: they were good or excellent in 3 cases but with a decrease in the laryngotracheal diameter of 36%, 28% and 7% respectively. The laryngotracheal calibre decreased in 2 patients to 45% due to partial fibrous stenosis. Resection and anastomosis was required in the remaining 2 patients after 11 and 12 years for severe re-stenosis. The 3 patients who underwent immediate surgical resection all had an excellent clinical and morphological result, with a decrease in the laryngotracheal diameter of only 7%, 13% and 19% after a follow-up of 18, 20 and 15 years, respectively. These results show that the growth capacity of scars in children's airways is closely related to residual sclerosis following the initial treatment. It is thus suggested that primary resection and anastomosis should be performed in as many cases as possible. In the performance of plastic procedures, special attention should be paid to complete resection of the fibrotic tissues. Finally, a very long postoperative follow-up is always required in children in order to assess the development of the airway.

Adolescent↗

PubMed1990

[Transposition of the temporal muscle and surgery of the middle third of the face. Technic, indications and results].

The authors reemploy the technique using the temporal muscle to fill in large surgical cavities after tumoral surgery of the middle 1/3 of the face. The purpose of this technique is to prevent crust formation after radiotherapy, and to improve esthetic results by preventing further cutaneous retraction. They expose their own technique, the results and the indications from 8 cases.

Adult↗

PubMed1988

Mixed human immunodeficiency virus (HIV) infection in an individual: demonstration of both HIV type 1 and type 2 proviral sequences by using polymerase chain reaction.

Sera from persons seroreactive to both human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), by whole-virus (VEIA) enzyme immunoassays (EIAs) for each virus, were selected from a seroprevalence study of 944 persons in Abidjan, Cote d'Ivoire, West Africa, in 1987. These sera were subsequently tested for HIV-1 and HIV-2 antibody specificity by type-specific peptide EIAs (PEIA) and western blot (WB) analysis for both viruses. Peripheral blood monocytes (PBMCs) from representative individuals were cultured in the presence of phytohemagglutinin-stimulated normal donor PBMCs. These cultures were periodically monitored for HIV-1 and HIV-2 proviral sequences by using the selective DNA amplification technique polymerase chain reaction (PCR). As an outgrowth of this study, we report the case of a person dually reactive by various serological techniques in whom proviral sequences from HIV-1 and HIV-2 were detected by PCR. This is the first confirmed case of a mixed HIV-1 and HIV-2 infection in a single individual.

Acquired Immunodeficiency Syndrome↗

PubMed1986