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author:("kessler, J.")
1.  Hospital injury rates in relation to socioeconomic status and working conditions 
To describe the risk of work injury by socioeconomic status (SES) in hospital workers, and to assess whether SES gradient in injury risk is explained by differences in psychosocial, ergonomic or organisational factors at work.
Workforce rosters and Occupational Safety and Health Administration injury logs for a 5‐year period were obtained from two hospitals in Massachusetts. Job titles were classified into five SES strata on the basis of educational requirements and responsibilities: administrators, professionals, semiprofessionals, skilled and semiskilled workers. 13 selected psychosocial, ergonomic and organisational exposures were assigned to the hospital jobs through the national O*NET database. Rates of injury were analysed as frequency records using the Poisson regression, with job title as the unit of analysis. The risk of injury was modelled using SES alone, each exposure variable alone and then each exposure variable in combination with SES.
An overall annual injury rate of 7.2 per 100 full‐time workers was estimated for the two hospitals combined. All SES strata except professionals showed a significant excess risk of injury compared with the highest SES category (administrators); the risk was highest among semiskilled workers (RR 5.3, p<0.001), followed by nurses (RR 3.7, p<0.001), semiprofessionals (RR 2.9, p = 0.006) and skilled workers (RR 2.6, p = 0.01). The risk of injury was significantly associated with each exposure considered except pause frequency. When workplace exposures were introduced in the regression model together with SES, four remained significant predictors of the risk of injury (decision latitude, supervisor support, force exertion and temperature extremes), whereas the RR related to SES was strongly reduced in all strata, except professionals.
A strong gradient in the risk of injury by SES was reported in a sample population of hospital workers, which was greatly attenuated by adjusting for psychosocial and ergonomic workplace exposures, indicating that a large proportion of that gradient can be explained by differences in working conditions.
PMCID: PMC2092542  PMID: 17182643
2.  Potential subtypes of Chlamydia psittaci based on effects of cortisone with cytochalasin B or cycloheximide. 
Strains of Chlamydia psittaci were differentiated as to their biological characteristics using growth in Vero cells. These host cells were chlamydial infected without centrifugation, but treated with either cortisone and cytochalasin B or cortisone and cycloheximide. The criterion was the time of 100% cytopathic effect and specific sloughing, accompanied by the maximum infectivity of C. psittaci. Possible subtypic characteristics were determined for three avian strains.
PMCID: PMC1255169  PMID: 3742349
3.  Two fatal cases of type E adult food-borne botulism with early symptoms and terminal neurologic signs. 
Journal of Clinical Microbiology  1986;23(3):616-618.
Type E botulism, one of the least common forms of botulinal intoxication on the East Coast of the United States, is described for two elderly patients with chronic underlying disease. Both patients consumed tainted kapchunka, a salted, ungutted whitefish. Gastrointestinal symptoms and signs were prominent, but neurologic complaints, although noted soon after the consumption of the fish in one patient, did not progress until late in the course of the patient's illness. One patient exhibited both urinary retention, which was reported mainly in one outbreak of type E botulism (M.G. Koenig, A. Spickard, M.A. Cardella, and D.E. Rogers, Medicine [Baltimore] 43:517-545, 1964), and muscular fasciculations, which have been rarely reported.
PMCID: PMC268705  PMID: 3514662
4.  Comparative titers of egg assay against immunofluorescent assay of Chlamydia psittaci. 
A comparison of titers was made between an egg assay and a direct fluorescent antibody assay of three chlamydial strains propagated in Vero cells with and without cortisone plus cytochalasin B. The titer of NJ-1 strain was similar in the egg titration and the fluorescent antibody assay in the untreated sample and a little lower for the sample treated with cytochalasin B and cortisone. The SCT and CDC strains had approximately the same titers in the egg titration and the fluorescent antibody assay for samples with and without the antimetabolites.
PMCID: PMC1236128  PMID: 3886106
5.  Growth of several strains of Chlamydia psittaci in Vero and McCoy cells in the presence of cytochalasin and cortisone. 
Chlamydia psittaci of avian and mammalian origin were grown in McCoy and Vero cells in the presence of cytochalasin B with cortisone acetate. Six turkey strains, one parrot strain, one human strain, one ovine strain and one bovine strain were used in this study. All strains, except the turkey strain NJ-1, grew to higher titers in Vero cells than in McCoy cells. Five of the six turkey strains could be grouped together because they induced cytopathic changes rapidly. The other turkey strain, along with the parrot, human and ovine strain, induced cytopathic changes more slowly and the bovine strain failed to cause cytopathic changes, but it did replicate in the cell culture system.
PMCID: PMC1236063  PMID: 6478298
6.  Goat serums for fluorescent antibody conjugates to chlamydial antigens. 
Serums from goats hyperimmunized with Chlamydia psittaci consistently produce antichlamydial fluorescent antibody conjugate of high titer. The titer of the fluorescent antibody conjugate prepared from a given serum correlated well with the titer obtained by agar gel precipitin, but not with the complement fixation. The agar gel precipitin test can be used to predict whether a given serum is satisfactory for use in production of a conjugate for direct fluorescent antibody tests. Serums with an agar gel precipitin titer of 1/8 or higher generally produce a usable fluorescent antibody conjugate. Labeling gamma globulins with fluorescein isothiocyanate at a ratio of 1/150 resulted in satisfactory fluorescent antibody conjugates. Cultures of Vero cells infected with chlamydiae were found to be suitable for titration of the fluorescent antibody conjugates.
PMCID: PMC1236045  PMID: 6372973
7.  Effects of cortisone, cytochalasin B and cycloheximide on strains of Chlamydia psittaci in cell cultures. 
Vero and McCoy cell cultures were tested for their susceptibility to Chlamydia psittaci in the presence of several antimetabolites, such as cortisone acetate, cytochalasin B and cycloheximide. Vero cells were more susceptible than the McCoy cell cultures as demonstrated by cytopathic changes, fluorescent antibody activity, and titer of C. psittaci. Although all of the antimetabolites increased these parameters, a mixture of cortisone and cytochalasin B was the most effective.
PMCID: PMC1235952  PMID: 6357413
8.  Direct immunofluorescence tests with counterstains for detection of Chlamydia psittaci in infected avian tissues. 
Different methods of preparation and serological evaluation of rabbit globulins for use in fluorescent antibody conjugate and different methods of counterstaining with fluorescent antibody tests were evaluated for detection of Chlamydia psittaci in infected turkey tissues. The agar gel precipitin reaction was that chosen for testing and selecting antiserums to be used for fluorescein isothiocyanate conjugation. The fluorescent antibody staining was most pronounced with conjugate made from globulins precipitated with ammonium sulfate. A direct fluorescent antibody method with Evans blue counterstain correctly identified "coded" specimens of C. psittaci-infected and noninfected turkey air sacs. However, naphthalene black was superior to Evans blue as a counterstain when infected pericardial sacs were tested.
PMCID: PMC1319921  PMID: 91417
9.  Optimal macroculture method for studying mitogenic stimulation of turkey lymphocytes. 
This report describes a method for culturing turkey lymphocytes in disposable, unwashed glass test tubes with Morton closures and for recovering lymphocytes on fiber glass filters with a cell harvester made of common laboratory equipment for assay of mitogenic stimulation. Optimal conditions for culture were established.
PMCID: PMC1277630  PMID: 352493
10.  Tween 80: a marker for differentiation of hog cholera and bovine viral diarrhea viruses. 
Markers for differentiating hog cholera and bovine viral diarrhea viruses were studied using Tween 80, chloroform, trichlorotrifluoroethane and tri (n-butyl) phosphate. Attenuated A and virulent Ames strains of hog cholera virus were employed. Moreover, the NADL PK-15 cell culture adopted strain and low cell culture passaged Purdue strain of bovine viral diarrhea virus were used. These viruses were reacted with 2,500 micrograms/ml of Tween 80 for one hour at 37 degrees C. When attenuated A and virulent Ames strains of hog cholera virus with titers greater than 10(6) and 10(5) plaque forming units respectively, were reacted with Tween 80 the titer of each strains was reduced by approximately 10(4) plaque forming units of virus. When either strain of bovine viral diarrhea virus was reacted with Tween 80, virus was not detected.
PMCID: PMC1277704  PMID: 188531
11.  Stabilization of hog cholera virus by dimethyl sulfoxide. 
The stability of hog cholera virus through five freeze-thaw cycles in the presence and absence of dimethyl sulfoxide was studied. In the absence of dimethyl sulfoxide the hog cholera virus titer was reduced 52% to 91% following successive freezing and thawing cycles. However, when dimethyl sulfoxide was added to the viral suspension the virus titer appeared to remain the same after the same number of freezing and thawing cycles.
PMCID: PMC1277503  PMID: 1236769
12.  Immunofluorescence Plaque Assay for African Swine Fever Virus 
Suitably diluted cell culture adapted African swine fever virus preparations were inoculated on VERO cell monolayers and grown on coverslips. Gum tragacanth was used as an overlay. After three days incubation at 37°C the infected cultures were fixed with acetone and stained with fluorescent antibody conjugate. Fluorescing plaques consisted of 20-30 infected cells.
Three statistical criteria for a quantitatively reliable assay were met: the Poisson distribution for plaque counts, linearity of the relationship between the concentration of virus and the plaque count and reproducibility of replicate titrations. The method is suitable for counts up to at least 70 plaques per 5 cm2 coverslip and computed titers are reproducible within 0.16 log units with a total of 300 plaques enumerated.
PMCID: PMC1319849  PMID: 4279763
13.  Differentiation Among Strains of Goat Mycoplasma by Incident Light Immunofluorescence 
Antigenic differentiation between strains of goat mycoplasma was studied by direct fluorescent antibody reactions employing incident (vertical) ultraviolet light. Agar colonies of the mycoplasma grown in petri dishes were fixed by alcohol in situ, and stained with conjugated globulin before examination with ultraviolet light.
The fluorescent antibody (FA) conjugate against Vom strain of Mycoplasma mycoides var. capri was Vom strain-specific, no cross reaction with Mexico, Connecticut, or Maryland strains. Similarly, the Mexico strain conjugate was specific for colonies of Mexico, and did not cross with the Vom, strain. Additionally, the conjugate of the PG-2 strain of Mycoplasma agalactiae, which was specific for the colonies of PG-2 was refractory for the strain #99 of M. agalactiae.
It was therefore possible to utilize an immunofluorescent technique (incident ultraviolet light) to demonstrate differences among strains of M. mycoides var. capri and M. agalactiae.
PMCID: PMC1319799  PMID: 4270812
14.  Vesicular Lesions Produced in Guinea Pigs by a Staphylococcus aureus Strain 
A bacterium isolated from vesicular lesions on foot pads of guinea pigs reproduced lesions similar to those seen in experimental infections of guinea pigs with foot-and-mouth disease virus. (FMDV). These bacterial lesions were produced with an inactivated FMDV suspension. Identification as Staphylococcus aureus was determined by growth characteristics on nutrient and blood agar, Gram staining, fermentation of mannitol and coagulase positive reactions. In addition, the organism was sensitive to concentrations of penicillin and streptomycin commonly used in laboratory diluents.
PMCID: PMC1319780  PMID: 4355472
15.  Comparative Study of Agar Mediums for Propagation of Ruminant Mycoplasma 
A brain heart infusion agar supplemented with 16.7% rabbit serum (BHIR) was found the most suitable for the culturing of ruminant mycoplasma. Gourlay medium and Perreau medium (4, 5) were not suitable for growth of Mycoplasma mycoides var. mycoides or M. agalactiae, but were satisfactory for M. mycoides var. capri.
Four strains of M. mycoides var. mycoides, three strains of M. agalactiae and three strains of M. mycoides var. capri were grown in our laboratory.
PMCID: PMC1319756  PMID: 4266704
16.  Incident Light Immunofluorescence of Alcohol-fixed Colonies of Ruminant Mycoplasma 
Two species of ruminant mycoplasma colonies had to be fixed in ethyl alcohol so that incident immunofluorescence method could be applied. In addition, the stain reaction had to be kept for 90 minutes at 37°C.
This fluorescent antibody (FA) method was developed to identify colonies of Vom strain of Mycoplasma mycoides var. capri, V-5 strain of M. mycoides var. mycoides, and PG-2 strain of M. agalactiaeon agar, using fluorescent ultraviolet light. Fluorescence was not demonstrated when heterologous conjugates or normal rabbit serum conjugate were applied but the reaction appeared to be specific for each strain of mycoplasma.
The FA method was able to differentiate specific mycloplasma colonies in mixed cultures.
PMCID: PMC1319754  PMID: 4121200
18.  Detection of African Horsesickness Viral Antigens in Tissues by Immunofluorescence 
The fluorescent antibody reaction was studied in tissues of ponies infected with African horsesickness virus (AHSV). Lung, spleen, lymph node, liver, skeletal muscle, intestine, stomach, nerve ganglion and kidney were sectioned and stained by the direct fluorescent antibody technique (FA). Fluorescence was demonstrated only in the spleen and could be inhibited by using unconjugated antiserum.
PMCID: PMC1319637  PMID: 4259931

Results 1-19 (19)