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Biomedical subjects

G Bergeron

Publications and source records attributed to G Bergeron.

At least 19 recordsLinked to original sources
PubMed1995

Development of bacterial biofilms in dairy processing lines.

Adherence of bacteria to various milk contact sites was examined by scanning electron microscopy and transmission electron microscopy. New gaskets, endcaps, vacuum breaker plugs and pipeline inserts were installed in different areas in lines carrying either raw or pasteurized milk, and a routine schedule of cleaning-in-place and sanitizing was followed. Removed cleaned and sanitized gaskets were processed for scanning or transmission electron microscopy. Adherent bacteria were observed on the sides of gaskets removed from both pasteurized and raw milk lines. Some areas of Buna-n gaskets were colonized with a confluent layer of bacterial cells surrounded by an extensive amorphous matrix, while other areas of Buna-n gaskets showed a diffuse adherence over large areas of the surface. Most of the bacteria attached to polytetrafluoroethylene (PTFE or Teflon) gaskets were found in crevices created by insertion of the gasket into the pipeline. Examination of stainless steel endcaps, pipeline inserts, and PTFE vacuum breaker plugs did not reveal the presence of adherent bacteria. The results of this study indicate that biofilms developed on the sides of gaskets in spite of cleaning-in-place procedures. These biofilms may be a source of post-pasteurization contamination.

Animals↗
PubMed1994

Hydromorphone patient-controlled analgesia (PCA) after coronary artery bypass surgery.

We conducted a study to compare the effectiveness of patient-controlled analgesia (PCA) technique to conventional analgesic therapy (CAT) after coronary artery bypass graft (CABG). The PCA group received hydromorphone 0.1 mg.hr-1 basal infusion and bolus doses of 0.2 mg Q 5 min (maximum 1.2 mg.hr-1) while the CAT group received morphine 2.5 mg iv Q 30 min prn until extubation followed by prn meperidine 1 mg.kg-1 im Q 4 hr or acetaminophen 325 mg with codeine 30 mg po (1 or 2 tablets) when oral intake was possible. The degree of pain was assessed using a Visual Analogue Scale (VAS) starting after extubation and every 6-8 hr for the next 60 hr. Holter monitoring was initiated one hour after patient arrival in the Intensive Care Unit (ICU) and continued for 72 hr. Other measured variables were pulmonary function, sedation, side effects and total opioid requirements. Results show that the day-to-day VAS pain score decreased in the PCA group (P < 0.001) while it remained unchanged in CAT patients. The PCA patients had lower VAS pain scores at extubation (P < 0.05). During the third postoperative day, the PCA group had a lower VAS pain score, a lower incidence of severe pain defined as a score > 5 on the VAS scale, and a reduced incidence of myocardial ischaemia (P < 0.01). However, there was no difference in the duration, severity, area under the curve (AUC), or heart rate during ischaemic events. Postoperative pulmonary function was abnormal in both groups (NS) with minimal recovery by the fourth day.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesia↗
PubMed1988

[Current forms of toxicomania in adolescents].

The authors analyse current aspects of toxicomania in young persons. Addiction to licit or illicit drugs usually originates in the conjunction of the use of a substance and a personality crisis, in a propitious socio-cultural context. Except in cases of overdoses which are the ultimate emergency, the follow-up care of adolescent drug addicts does not require specialist therapy. It is the business of adult counsellors to listen to these adolescents and take full responsibility for them.

Adolescent↗
PubMed1985

Method for improving the detection of viruses in fecal samples.

A method is described that improved the detection of viruses in fecal samples by electron microscopy. The virus particles were concentrated, and much of the background debris was removed by adsorption of viruses on meat protein added to the fecal sample at a low pH and a low salt concentration. Viruses were eluted by raising the pH and the salt concentration. Further concentration was achieved by acid precipitation and vacuum dialysis.

Adsorption↗
PubMed1985

Ultrastructural changes observed in Rickettsia rickettsii incubated at different temperatures in cell-free medium.

When cells of Rickettsia rickettsii were suspended at different temperatures in growth medium free of host cells, ultrastructural changes were observed in some of these organisms. Depending upon the temperature and length of incubation, loosely organized cells developed into compact, intensely stained, rod-shaped organisms. These compact cells closely resembled the morphology of the original culture of Rickettsia used for inoculation. Morphological changes were primarily noted in cells maintained at 21 degrees C. The viability of the cells was also affected by the temperature of incubation.

Culture Media↗
PubMed1982

Agreement among teacher, peer, and self-ratings of children's aggression, withdrawal, and likability.

This study examined the relationship among teacher, peer, and self-ratings of children's social behavior. The Pupil Evaluation Inventory was completed by 172 first-graders, 346 fourth-graders, 283 seventh-graders, and 30 teachers. Groups of deviant responders and controls were also selected from the total sample on the basis of peer-rated aggression and withdrawal scores. Interrater agreement was consistently greater between peer and teacher ratings than between self-ratings and either peer or teacher ratings. Discrepancies between raters were greatest for children with more deviant scores, with peer ratings providing the highest estimates of deviant behavior, and self-ratings yielding the lowest. Self ratings were lower than teacher or peer ratings on aggression and withdrawal, and higher on likability. Aggression produced greatest agreement between raters. Agreement was uninfluenced by the cognitive maturity of peer evaluators. The results suggest that the selection of raters should be influenced by the class of behaviors to be evaluated and the context in which they occur.

Aggression↗
PubMed1974

Concentration of enteric viruses from water with lettuce extract.

A method for recovering enteroviruses, adenovirus, and reovirus from water with lettuce extract is described. Lettuce extract at pH 8.5 was added to the sample and the pH was reduced stepwise with hydrochloric acid to 4.0 to 4.5. The flocculent lettuce-extract particles, and adsorbed virus, were readily removed from solution by low-speed centrifugation. Electron microscopy suggests that, under conditions suitable for adsorption, virus particles are coated with the lettuce-extract colloid.

Adenoviridae↗
PubMed1969

Mesosomes in Escherichia coli.

When Escherichia coli was grown in a synthetic medium and fixed with osmium, sections of the cells revealed clearly defined mesosomes. These mesosomes appeared to develop, in dividing cells, as coiled infoldings of the cytoplasmic membrane. Mature mesosomes formed a link between the cytoplasmic membrane and the nucleus of the cell. The arrangement of the mesosomes in dividing cells led to the hypothesis that division of the nucleus in these cells is accomplished by two separate polar mesosomes. One mesosome is derived from the parent cell and is present at one pole of the daughter cell. The other is freshly synthesized at or near the newly forming pole of the daughter cell. While the old mesosome remains attached to the chromosome received from the parent cell, the newly synthesized mesosome becomes attached to and initiates replication of the new chromosome. As the cell grows and elongates, the two mesosomes, attached to their respective chromosomes move apart, thus effecting nuclear division.

Cell Division↗
PubMedDate not supplied

Vero cells co-infected with Chlamydia trachomatis and herpes simplex virus type 2: a scanning and transmission electron microscope study.

Vero (African Green Monkey Kidney) cells infected with Chlamydia trachomatis (serovar L2) (CT-L2) for 48 hr and superinfected with herpes simplex virus type 2 (HSV-2) were fixed 24 hr later and examined with the transmission electron microscope (TEM) and scanning electron microscope (SEM). Ultrastructural examination of the co-infected cells showed that, although many CT-L2 inclusions were present, most were empty of reticulate bodies or elementary bodies. However, large numbers of viruses were observed in the co-infected Vero cells and, in some instances, were seen inside the CT-L2 inclusions. SEM studies of the co-infected cells revealed a swelling and rounding up of the Vero cells typical of a CT-L2 or HSV-2 infection. The outer surface of the co-infected cells were covered with many long microvilli typical of HSV-2 infection with only a few surface protruberances similar to those found in CT-L2 infected cells.

Animals↗