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Biomedical subjects

M Swanson

Publications and source records attributed to M Swanson.

At least 19 recordsLinked to original sources
PubMed2001

Latex aeroallergen quantification in hospitals of Moscow, Russia.

BACKGROUND: Health care workers (HCWs) who use latex gloves regularly are at a significant risk for developing allergic sensitization to natural rubber latex (NRL) proteins. The airborne route of exposure presents a hazard for sensitization and subsequent allergic symptoms. OBJECTIVE: The purpose of this study was to measure the content of the NRL proteins in the air of work areas (laboratories, treatment rooms, operating rooms, examination rooms, and dentist's treatment rooms) in eight Moscow hospitals where the employees used powdered latex gloves. METHODS: The air samples were collected by a volumetric filtration method using a static air sampler at a flow rate of 3 L/second. Airborne particles were collected onto polytetrafluoroethylene filters rated 99.9% efficient at 0.3 microm. The NRL allergens were extracted from the air filter samples in phosphate-buffered saline and quantified by an inhibition immunoassay using a five-person pool of sera containing latex-specific human immunoglobulin E. RESULTS: The airborne latex allergen concentrations in 11 areas (including positive control) where latex gloves were used varied from 5 to 26 ng/m3. Conversely, in 12 areas where latex gloves were seldom used or where powdered-free latex gloves were used allergen levels were not detectable (including two negative controls). The highest concentration of latex allergen (26 ng/m3) was found in an examination room of a gynecology department. Low and moderate concentrations were detected in most operating rooms, and low concentrations in the laboratories and treatment rooms. CONCLUSIONS: This study indicates that, in general, the airborne NRL concentrations in the work areas of Moscow hospitals are rather low compared with NRL concentrations reported from American hospitals and are dependent on the intensity of latex glove usage.

Air Pollution, Indoor↗
PubMed2000

Chemical and mutagenic properties of asphalt fume condensates generated under laboratory and field conditions.

Exposure to asphalt fumes is widely recognized as a potential occupational health concern for paving and roofing workers. Two studies suggest that asphalt fumes generated in the laboratory are carcinogenic to mice. In this study, asphalt fume condensate (AFC) was collected from the head space of an operating hot mix asphalt storage tank and from a laboratory fume-generating apparatus operating at approximately 149 degrees C and 316 degrees C. Salmonella assays for mutagenesis, in vitro chromosomal aberration assays using Chinese hamster ovary (CHO) cells, chemical analyses, and simulated distillations were performed using gas chromatography to characterize the toxicological and chemical properties of AFCs generated by these two methods. The 316 degrees C lab AFC sample was more mutagenic in the Salmonella assay than the 149 degrees C lab AFC sample, with mutagenicity indices (MIs) of 8.3 and 5.3, respectively. AFCs collected from the storage tank were not mutagenic. Chromosomal aberration assays of all AFCs were negative. Chemical analyses and simulated distillations showed substantial differences in the chemical composition of the AFC samples. The 316 degrees C lab AFC sample contained more higher-boiling-point (three- and four-ring) polycyclic aromatic sulfur heterocycle compounds than the 149 degrees C lab AFC sample, and both lab AFC samples contained 5 to 100 times more of these compounds than AFC samples collected from the asphalt storage tank. These results are consistent with other data reported in the scientific literature describing the carcinogenicity of higher-boiling-point sulfur heterocycle compounds. In contrast to other recent studies, the results of this study indicate that the chemical composition and toxicological properties of laboratory-generated asphalt fumes are not representative of those properties of fumes to which workers and the public might be exposed.

Air Pollutants, Occupational↗
PubMed2000

Cloning of the bovine immunodeficiency virus gag gene and development of a recombinant-protein-based enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was established for the rapid detection of specific bovine immunodeficiency virus (BIV) antibodies in cattle, using recombinant Gag protein as an antigen. The gag coding region from BIV was cloned into an expression vector, pQE32, which expressed high levels of recombinant protein from Escherichia coli. The ELISA was standardized by a checkerboard titration against known BIV-positive and -negative sera from cattle and a monoclonal antibody to the Gag protein. A total of 139 cattle serum samples, from the diagnostic laboratory at Kansas State University, Manhattan, and from the Dairy Station, Louisiana State University, Baton Rouge, were compared by ELISA and immunoblot assays for the detection of BIV-specific antibodies. Of 26 cattle sera samples which tested positive using the immunoblot assay, 23 were positive by ELISA, thus establishing a strong correlation between the two tests. The sensitivity and specificity of ELISA relative to immunoblotting were 0.88 and 0.93, respectively. ELISA proved to be as specific as immunoblotting but was much less time-consuming and easier to perform.

Animals↗
PubMed2000

Geographic distribution of human immunodeficiency virus-associated Pneumocystis carinii pneumonia in San Francisco.

The epidemiology of Pneumocystis carinii pneumonia (PCP) and its geographic distribution are incompletely understood. We examined the influence of geographic location as a risk factor for PCP through a retrospective case-control study of HIV-infected persons evaluated for PCP at San Francisco General Hospital. Subjects had microscopically confirmed PCP diagnosed between January 1996 and June 1999. Control subjects had a presentation suggestive of PCP, but had bronchoalveolar lavage examination that did not reveal P. carinii. Medical chart review was performed to obtain demographic and clinical characteristics of the subjects as well as their addresses at time of PCP evaluation. Multivariate analyses were performed in order to identify variables associated with PCP. Lack of P. carinii prophylaxis and a CD4 cell count </= 50 cells/microl were independent predictors of an increased risk of PCP. Interestingly, subjects living in the 94103 zip code had a significantly lower risk of PCP than subjects in other areas (odds ratio = 0.2, 95% confidence interval 0.1-0.6, p < 0.01). This effect was present despite controlling for risk factors for PCP such as use of prophylaxis or antiretroviral therapy, CD4 cell count, and HIV RNA level. We conclude that residence in the 94103 zip code of San Francisco is associated with a substantially lower risk of PCP than residence in other areas of the city.

AIDS-Related Opportunistic Infections↗
PubMed1999

HIV RNA and CD4 cell count response to protease inhibitor therapy in an urban AIDS clinic: response to both initial and salvage therapy.

OBJECTIVE: To determine the HIV RNA and CD4 cell response to both initial and salvage therapy with protease inhibitor-based therapy, and to examine the relationship between the virological response and pre-therapy characteristics. DESIGN: Observational cohort. SETTING: University-based public hospital AIDS clinic. PATIENTS: HIV-infected adults who received at least 16 continuous weeks' therapy with a potent protease inhibitor (indinavir, ritonavir or nelfinavir)-based regimen, and who have had at least 48 weeks of follow-up. MAIN OUTCOME MEASURES: Plasma HIV RNA and CD4 cell count response at week 48 of therapy for patients receiving their first protease inhibitor-containing regimen, and at week 24 of therapy with a salvage regimen. RESULTS: Of the 337 patients analysed, 170 (50.2%) had a successful outcome (HIV RNA <500 copies/ml after 48 weeks of treatment). Independent predictors of virological failure were higher baseline HIV RNA level, lower baseline CD4 cell count and failure to initiate at least one new nucleoside analog simultaneously at the time protease inhibitor therapy was initiated. The risk of failure increased incrementally across most HIV RNA and CD4 cell strata, with significant increases as the HIV RNA increased above 4.5 log10 copies/ml and the CD4 cell count fell below 100 cells/mm3 (P< or =0.01). The CD4 cell count remained above baseline to week 48 in most patients, regardless of the HIV RNA response. Of the 99 patients who experienced virological failure and switched to a salvage regimen, only 22 (22%) achieved an undetectable HIV RNA level 24 weeks after initiating salvage therapy. Independent predictors of failure with salvage therapy included an HIV RNA greater than 4.0 log10 RNA copies/ml at the time of the switch and failure to use a non-nucleoside reverse transcriptase inhibitor (NNRTI) in the salvage regimen. CONCLUSION: Failure of potent protease inhibitor therapy to suppress HIV RNA levels below detectable levels is common in clinical practice, and can often be explained by their suboptimal use. CD4 T cell counts remain above baseline for at least one year in most patients experiencing virological failure. Successful salvage therapy, which was uncommon, was associated with a low plasma HIV RNA at the time of the switch and the use of a new class of antiretroviral agents (NNRTI) in the salvage regimen.

Adult↗
PubMed1998

Structure-activity relationship of 2-[[(2-pyridyl)methyl]thio]-1H- benzimidazoles as anti Helicobacter pylori agents in vitro and evaluation of their in vivo efficacy.

A relationship between the structure of 21 2-[[(2-pyridyl)methyl]thio]-1H-benzimidazoles (6) and their anti Helicobacter pylori activity expressed as minimum bactericidal concentration (MBC) values is described. Observed MBCs ranged from 256 to 1 microg/mL. The structure-activity relationship (SAR) showed that larger and more lipophilic compounds, especially compounds with such substituents in the 4-position of the pyridyl moiety, generally had lower MBC values. Four new compounds that were predicted to be potent by the established SAR model were synthesized and tested. One such compound, i.e., 2-[[(4-[(cyclopropylmethyl)oxy]-3-methyl-2-pyridyl)methyl]thio]-1H-be nzimidazole (18), was tested for in vivo efficacy in a mouse Helicobacter felismodel (125 micromol/kg bid given orally for 4 days, n = 4). Unfortunately, antibacterial activity could not be clearly demonstrated in this model. Instead a potent acid secretion inhibition was observed. This finding was attributed to the methylthio compound being oxidized to the corresponding methyl sulfinyl derivative, i.e., a proton pump inhibitor, in vivo. Although the antibacterial activity had the potential of decreasing H. felis cell counts in vivo the proton pump inhibitory effect became dominant and actually promoted H. felis cell growth. Hence, we conclude that the antibacterial utility of the 2-[[(2-pyridyl)methyl]thio]-1H-benzimidazoles (6) as a compound class is compromised by their propensity to become proton pump inhibitors upon metabolic oxidation in vivo.

Animals↗
PubMed1998

The Gcn4p activation domain interacts specifically in vitro with RNA polymerase II holoenzyme, TFIID, and the Adap-Gcn5p coactivator complex.

The Gcn4p activation domain contains seven clusters of hydrophobic residues that make additive contributions to transcriptional activation in vivo. We observed efficient binding of a glutathione S-transferase (GST)-Gcn4p fusion protein to components of three different coactivator complexes in Saccharomyces cerevisiae cell extracts, including subunits of transcription factor IID (TFIID) (yeast TAFII20 [yTAFII20], yTAFII60, and yTAFII90), the holoenzyme mediator (Srb2p, Srb4p, and Srb7p), and the Adap-Gcn5p complex (Ada2p and Ada3p). The binding to these coactivator subunits was completely dependent on the hydrophobic clusters in the Gcn4p activation domain. Alanine substitutions in single clusters led to moderate reductions in binding, double-cluster substitutions generally led to greater reductions in binding than the corresponding single-cluster mutations, and mutations in four or more clusters reduced binding to all of the coactivator proteins to background levels. The additive effects of these mutations on binding of coactivator proteins correlated with their cumulative effects on transcriptional activation by Gcn4p in vivo, particularly with Ada3p, suggesting that recruitment of these coactivator complexes to the promoter is a cardinal function of the Gcn4p activation domain. As judged by immunoprecipitation analysis, components of the mediator were not associated with constituents of TFIID and Adap-Gcn5p in the extracts, implying that GST-Gcn4p interacted with the mediator independently of these other coactivators. Unexpectedly, a proportion of Ada2p coimmunoprecipitated with yTAFII90, and the yTAFII20, -60, and -90 proteins were coimmunoprecipitated with Ada3p, revealing a stable interaction between components of TFIID and the Adap-Gcn5p complex. Because GST-Gcn4p did not bind specifically to highly purified TFIID, Gcn4p may interact with TFIID via the Adap-Gcn5p complex or some other adapter proteins. The ability of Gcn4p to interact with several distinct coactivator complexes that are physically and genetically linked to TATA box-binding protein can provide an explanation for the observation that yTAFII proteins are dispensable for activation by Gcn4p in vivo.

Animals↗
PubMed1998

Breast cancer risk and lifetime occupational history: employment in professional and managerial occupations.

OBJECTIVE: In this case-control study, occupational histories were used to assess the relation between risk of breast cancer and employment in professional and managerial occupations while adjusting for reproductive and other risk factors. METHODS: Incident, primary, female cases of breast cancer diagnosed between 1986 and 1991, and randomly selected controls were interviewed to obtain detailed medical, reproductive, and occupational histories. Mantel-Haenszel crude odds ratios (OR) and 95% confidence intervals (95% CIs) were used to estimate risk of breast cancer related to the job of longest duration. Unconditional logistic regression was used to estimate crude and adjusted ORs and 95% CIs associated with having ever been employed and duration of employment in a professional or managerial occupation. RESULTS: A non-significant threefold increase in risk was found among premenopausal women whose major job was in the occupational category of precision production, craft, and repair (95% CI 0.90 to 20.35). No increase in risk was found for premenopausal women whose major job was a managerial or professional occupation. However, an inverse relation between risk of premenopausal breast cancer and having ever held a professional or managerial job was observed (OR 0.53, 95% CI 0.34 to 0.82). This relation was strongest for women who worked one to 10 years (OR 0.47, 95% CI 0.29 to 0.77). Postmenopausal breast cancer was not related to professional and managerial employment. CONCLUSIONS: In this population, employment in professional and managerial occupations is not associated with postmenopausal risk of breast cancer, but seems to be related to a reduction in risk of premenopausal breast cancer. Methodological limitations of this study including response rates are discussed.

Adult↗
PubMed1998

Compliance with and typical usage of artificial tears in dry eye conditions.

BACKGROUND: Although the literature on dry eye is extensive, little has been written about the typical use of tear supplements among the clinical population. METHODS: This study consisted of chart reviews and telephone surveys. Self-reported use of tear supplements was evaluated. RESULTS: At the time of the survey, 63% of those recommended to use artificial tear solutions (114 of 229) continued to do so. The discontinuation rate was higher for ointments, with 53% (47 of 89) having stopped using a recommended ointment. The majority of those continuing to use drops will use one or two drops per day (30 gtts/30 days, +/- 89). In addition to the extreme amount of variability in the number of artificial tears used by any individual, a great deal of day-to-day variability is seen within any individual. CONCLUSIONS: Patients appear to titrate dosage to symptoms on any given day. Given this, there may be little reason to prescribe a specific dosage regimen for the majority of persons using tears. Researchers who are looking at the effectiveness of tear supplements need to take into account the individual variability of use in tear supplements. When prescribing artificial tears, patient education regarding purpose for treatment, specific agent, and dosage used may improve relatively low compliance rates.

Adolescent↗
PubMed1997

The workup for bariatric surgery does not require a routine upper gastrointestinal series.

BACKGROUND: Morbid obesity is a serious disease that afflicts over five million Americans, threatening their health with such co-morbidities as diabetes, arthritis, pulmonary failure and stroke. Surgery is the only effective therapy, providing long-term control of weight, diabetes, pulmonary failure, and hypertension for as long as 14 years. Because the operation presents a major expense, this study examined whether X-ray examination of the gut could be omitted safely as a cost-saving measure. METHODS: The records of 814 consecutive morbidly obese patients who underwent gastric bypass were reviewed to determine: (1) whether these individuals had undergone an upper gastro-intestinal (GI) series, and (2) if these studies influenced therapy or caused cancellation or postponement of surgery. RESULTS: Of the 814 patients, 657 (80.7%) underwent a preoperative GI radiography. Of these examinations, 393 (59.8%) were normal, with the following abnormalities in the remaining 264: hiatal hernia, 164; esophageal reflux, 39; Schatzki's ring, 18; small bowel diverticula, four; renal stones, four; malrotation, three; gall stones, two; pyloric ulcer, one; possible pelvic mass, one; calcified leiomyoma, one; and dysphagial lusoria, one. None of these findings resulted in cancellation or a delay in surgery. CONCLUSIONS: The upper GI series can be safely omitted from the routine preoperative evaluation of patients undergoing gastric bypass. At a cost of $741.00 per examination, this change represents significant potential savings. Similar evaluations of other routine preoperative tests may well provide a better basis for the evaluation of these complex patients.

Adult↗
PubMed1996

A plant viral coat protein RNA binding consensus sequence contains a crucial arginine.

A defining feature of alfalfa mosaic virus (AMV) and ilarviruses [type virus: tobacco streak virus (TSV)] is that, in addition to genomic RNAs, viral coat protein is required to establish infection in plants. AMV and TSV coat proteins, which share little primary amino acid sequence identity, are functionally interchangeable in RNA binding and initiation of infection. The lysine-rich amino-terminal RNA binding domain of the AMV coat protein lacks previously identified RNA binding motifs. Here, the AMV coat protein RNA binding domain is shown to contain a single arginine whose specific side chain and position are crucial for RNA binding. In addition, the putative RNA binding domain of two ilarvirus coat proteins, TSV and citrus variegation virus, is identified and also shown to contain a crucial arginine. AMV and ilarvirus coat protein sequence alignment centering on the key arginine revealed a new RNA binding consensus sequence. This consensus may explain in part why heterologous viral RNA-coat protein mixtures are infectious.

Alfalfa mosaic virus↗
PubMed1996

A comparison of two noninvasive methods of blood pressure measurement in the triage area.

OBJECTIVE In triage of patients in the emergency department, nurses can identify conditions such as elevated blood pressure that can lead to serious health problems. It is imperative that the method used to evaluate blood pressure is dependable and accurate. The introduction of new technology may yield results that are not comparable to traditional measures. Therefore we compared the traditional auscultatory method of measuring blood pressure with the use of an automated device. METHODS The blood pressure of 100 healthy adult volunteers was measured first with the traditional cuff method and then with an automated device (IVAC model 4200). The measurements were recorded and then compared for each individual. RESULTS The mean difference between the paired systolic measurements was 4.3 mm Hg (p = 0.0001). The mean difference between the paired diastolic measurements was 1.3 mm Hg. There was a clinically significant difference (> 9 mm Hg) in 37% of the systolic readings and 26% of the diastolic readings. In 76% of those clinically significant systolic differences, the IVAC 4200 measurement exceeded the manual method. For the clinically significant diastolic differences, 58% of the IVAC 4200 measurements were greater than the manual method. CONCLUSION Clinicians must be cautious when using new technology to measure blood pressure. Results may not be comparable with results obtained with the traditional method.

Adolescent↗
PubMed1996

Measurement of natural rubber proteins in latex glove extracts: comparison of the methods.

BACKGROUND: Health care workers and individuals with frequent contact with latex are at risk for latex protein allergy. OBJECTIVE: The purpose of this study was to compare several established methods for measuring protein in extracts from latex-containing medical devices. METHODS: Extracts from latex gloves were analyzed for natural rubber proteins using a modified Lowry assay and two different immunochemical assays. The immunochemical methods were competitive inhibition assays that employed either immune rabbit serum or human serum with antibodies directed against natural rubber proteins. RESULTS: Seventy extracts representing five different brands of gloves from four manufacturers were analyzed. A good linear correlation (R = 0.88) was found between the immunoassay methods. Correlation to the modified Lowry method was not possible because many of the samples were below the limit of detection for the Lowry assay. Reference extracts and antisera were further characterized by Western blot analysis. The data demonstrate that the proteins recognized by rabbit antisera and the proteins recognized by human IgE are similar. The greatest difference in the immunochemical assays appears to be the relative binding of the antibody sources to high and low molecular weight natural rubber proteins in the reference extracts. CONCLUSIONS: The immunochemical assays are specific for latex proteins and provide a more sensitive and biologically relevant method for determining protein levels in latex medical products.

Animals↗
PubMed1996

Public perceptions of an appropriate donor card/brochure.

Donor card/brochures have not had a major impact on donation, though considerable resources have been invested in their development and distribution. One reason for this may be that they have not been evaluated by the people expected to sign them: the American public. A focus group format was used to develop a quantitative survey to assess the public's perception of an appropriate donor card/brochure. Several donor card/brochures were studied to compare and evaluate their effectiveness, content, format, and acceptance of the message. A donor card/brochure was designed that was based on the results of the survey: it included a business reply card for further evaluation. The newly developed donor card/brochure continues to be viewed positively by those returning business reply cards. Most have signed the card and discussed donation with family members.

Attitude to Health↗
PubMed1996

Organ transplantation at the Hartford Transplant Center.

Over 1,243 organ transplants have been performed at the Hartford Transplant Center over the past two decades. Survival in kidney, heart, liver, and pancreas patients is at or above the national average. Hartford was one of the first centers to use triple immunosuppression, which significantly improved survival in kidney transplantation. For recipients of kidneys from living related donors and cadaveric kidneys, two-year actuarial graft survival has been 98% and 83%, respectively, over the last five years. For heart and liver transplants, two-year survival has been 79% and 67%, respectively. Despite high success rates at most transplant centers, donor organs remain scarce. This problem needs to be addressed through increased cooperative efforts in the health-care community and the general public.

Adolescent↗
PubMed1995

Lifetime alcohol consumption and risk of breast cancer.

The relation of lifetime alcohol intake to risk of breast cancer in pre- and postmenopausal women was examined in a case-control study in western New York. Cases with incident primary histologically confirmed breast cancer diagnosed during the period 1986-1991 (n = 740) and controls, frequency age-matched women drawn from New York state driver's license records (age < 65 yrs) and from records of the Health Care Finance Administration (age > or = 65 yrs, n = 810), were interviewed regarding intake of wine, beer, and hard liquor 2, 10, and 20 years ago and at 16 years of age. Although women in this study had generally low intakes of alcohol, there was little evidence of increased risk of breast cancer with intake of alcohol at any of the time periods or with an index of total lifetime intake. There was a weak indication of an increase in risk with beer for intakes of at least one drink per day. This risk was evident for 2, 10, and 20 years ago but not at 16 years of age. In this group with relatively low intakes of alcohol, evidence was weak for an association of increased risk of breast cancer with intake of alcohol, with the possible exception of a weak association with beer intake.

Adolescent↗