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Biomedical subjects

P Marcus

Publications and source records attributed to P Marcus.

At least 19 recordsLinked to original sources
PubMed2005

Surface characterization of three marine bacterial strains by Fourier transform IR, X-ray photoelectron spectroscopy, and time-of-flight secondary-ion mass spectrometry, correlation with adhesion on stainless steel surfaces.

Adhesion of bacterial strains on solid substrates is likely related to the properties of the outer shell of the micro-organisms. Aiming at a better understanding and control of the biofilm formation in seawater, the surface chemical composition of three marine bacterial strains was investigated by combining Fourier transform IR spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary-ion mass spectrometry (ToF-SIMS). The D41 strain surface showed evidence of proteins, as deduced from the NH2 and NCO XPS and ToF-SIMS fingerprints; this strain was found to adhere to stainless steel, glass, or Teflon surfaces in a much higher quantity (2 orders of magnitude) than the two other ones, DA and D01. The latter are either enriched in COOH or sulfates, and this makes them more hydrophilic and less adherent to all substrates. Correlations with physicochemical properties and adhesion seem to demonstrate the role of the external layer composition, in particular the role of proteins more than that of hydrophobicity, on their adhesion abilities.

Adhesiveness↗
PubMed2001

Labelling and binding of poly-(L-lysine) to functionalised gold surfaces. Combined FT-IRRAS and XPS characterisation.

We compare herein the interfacial reactivity of self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA), 1-undecanethiol (UDT) and 11-mercaptoundecanol (MUD) on gold surfaces towards aqueous solutions of poly-(L-lysine) (PL). Liquid-phase labelling of PL with the alkyne dicobalt hexacarbonyl cluster 1 combined with analysis of the substrates by Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS) and X-ray photoelectron spectroscopy (XPS) revealed that irreversible binding of PL occurred in all cases. However, the mechanism of binding involved differed markedly from one monolayer to the other. The main mode of interaction of PL to MUA SAM was of electrostatic nature between the terminal carboxylate of MUA and the ammonium groups of PL. For a similar number of bound thiolate molecules, the UDT adsorbed layer was found less continuous than the MUA one, allowing a higher fraction of PL to directly bind to the gold surface. As for MUD, very little thiolate molecules were adsorbed, leaving bare gold surface areas for non specific adsorption of PL.

Journal Article↗
PubMed2001

Vaginal bleeding from massive hemoperitoneum. A case report.

BACKGROUND: A gynecology service is often asked to consult and evaluate in-house patients with vaginal bleeding. CASE: A 31-year-old, Asian woman with a history of end-stage renal disease and hemodialysis was admitted to the hospital with a falling hematocrit. She subsequently began to have heavy vaginal bleeding. Computed tomography suggested a peritoneal-cervical fistula. Subsequent exploratory laparotomy documented that the bleeding was caused by retrograde flow of a hemoperitoneum. CONCLUSION: This appears to be the first reported case of retrograde flow from a hemoperitoneum causing vaginal bleeding. Although unusual, this case expands the differential diagnosis when evaluating vaginal bleeding.

Adult↗
PubMed1998

Uranium in urine--normalization to creatinine.

"Spot samples" of urine are routinely used to monitor occupational exposure to uranium and other toxic heavy metals, such as mercury, lead, and cadmium. In the present work, it was shown that diurnal variations in the uranium concentration in different urine samples from the same individual could be quite large. However, these variations were in correlation to the creatinine level of the same samples, with values of R = 0.72-0.99, for the five subjects studied here. Thus, it is proposed here that uranium concentrations in "spot" urine samples be expressed in terms of ng uranium g(-1) creatinine rather than ng uranium L(-1). Once the 24-h creatinine level is estimated for the individual based on weight, height and age, the adjusted values can be used for determination of the internal dose of uranium.

Circadian Rhythm↗
PubMed1993

Characteristics of suicides by inmates in an urban jail.

OBJECTIVE: The authors' goals were to describe the characteristics of suicides committed by inmates in custody of the New York City Department of Correction between 1980 and 1988. METHODS: Data on suicides were collected from records of the jail health services, the municipal medical examiner's office, and the city's prison death review board, as well as from reports of the New York State Commission of Correction and other documents. RESULTS: The authors identified 48 suicides committed by inmates during the study period. Forty-two percent of the suicides occurred within the first 30 days of incarceration, and 50 percent occurred within three days of a court appearance. More than 90 percent of suicides were by hanging. Ninety-one percent of suicides took place in cells in which the inmate was housed alone. Fifty-two percent of the inmates who committed suicide had a major psychiatric diagnosis, and 46 percent had a history of inpatient or outpatient psychiatric care. CONCLUSIONS: The authors recommend that all inmates with a psychiatric history or potential suicidality be identified and linked with ongoing mental health services while incarcerated, that potentially suicidal inmates never be housed alone in a cell, and that correctional staff be trained to recognize potentially self-destructive inmates and to prevent suicide.

Adolescent↗
PubMed1992

Improving dental epidemiologic data collection with computers.

A computerized dental data recording system (DDRS) was developed for the New England Elder Dental Study to improve data quality and increase field staff efficiency. The DDRS displays video screens similar to traditional paper forms to record data on coronal and root caries, dentate and denture status, subacute bacterial endocarditis screening, gingival bleeding, calculus, and periodontal attachment level. DDRS provides facilities for date and exam-component time tracking, on-line contextual comments, random record retrieval, editing, data backup, and data output in various data formats. This study compared the DDRS with a paper-form system for data entry accuracy. Dental caries and periodontal disease measurement data from 38 subjects were recorded on paper forms and independently entered using DDRS. The DDRS identified 150 illogical data errors, 39 inconsistent data errors, 7 invalid data and 34 miscellaneous data errors. Four technicians with field experience using both paper forms and DDRS reported time savings using DDRS in the field. DDRS has the potential for additional time savings by minimizing the time for data coding, cleaning, and management. Results demonstrate that DDRS could improve the quality of oral epidemiologic data by mandating strict adherence to protocols, preventing errors, and increasing field efficiency.

Computers↗