Showing papers on "Typing published in 1982"

Sodium dodecyl sulfate-polyacrylamide gel typing system for characterization of Neisseria meningitidis isolates.

Abstract: Thirty to fifty percent of group B and group C Neisseria meningitidis carrier isolates are not serotypable with existing outer membrane protein typing sera. A typing system based on differences in the outer membrane protein profiles after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was therefore developed as an adjunct to existing serotyping methods. Although most N. meningitidis strains contain several outer membrane proteins visible by SDS-PAGE, there are only one to three predominant proteins. The SDS-PAGE profiles of these major proteins were used to establish 10 different PAGE types. Greater than 95% of all meningococcal isolates, regardless of serogroup, fit into 1 of the 10 PAGE types. The outer membrane protein profile of individual strains after SDS-PAGE was constant when outer membrane fractions were prepared from the same strain on several different days. A comparison of gel profiles of meningococcal isolates obtained from different sites of the same patient revealed no significant differences among both major and minor proteins for isolate sets thus far examined. Characterization of strains by PAGE type can be a valuable epidemiological tool in addition to serotyping and in the absence of specific serotype antisera.

A simple and practical method for typing and strain differentiation of herpes simplex virus using infected cell DNAs.

Abstract: A simple and practical method for typing and strain differentiation of herpes simplex virus (HSV) isolates, based upon analysis of the restriction endonuclease cleavage patterns of viral DNAs, was established by using unlabeled infected cell DNAs. The preparation of infected cell DNA is technically easier than that of purified viral DNA or of radiolabeled viral DNA. The method provides a powerful and practical tool for epidemiological and clinical studies of HSV infection, which can be performed in most diagnostic laboratories. In order to select suitable restriction endonucleases for the study of HSV isolates, the cleavage patterns of viral DNAs (strains MacIntyre, HF, UW-268, and SAV) with 12 enzymes were analyzed. Several enzymes, Bam HI, Kpn I, Pst I, Sal I, Sst I, and Xho I, were found to be useful for both typing and strain differentiation. With this method, HSV isolates from different individuals and from the same individual were analyzed by digestion of their infected cell DNAs with Bam HI. Six isolates from epidemiologically unrelated individuals were readily typed and differentiated from each other. Three isolates from the same individual showed very similar patterns. However, there was a small degree of difference between the first two isolates and the third isolate.

Further development of a bacteriocin typing system for Clostridium perfringens.

Abstract: The specificity of typing Clostridium perfringens with bacteriocins was improved by adding new bacteriocins and deleting others from the original typing set of ten. A total of 516 new isolates of Cl. perfringens were screened for bacteriocin production and, of these, 162 strains (31%) were found to be producers. The sensitivity patterns obtained by testing 40 bacteriocins against 200 isolates of Cl. perfringens were recorded and the data subjected to a computer analysis. A total of 18 bacteriocins capable of dividing the 200 isolates into 98 typing patterns was selected. The repro-ducibility of the new system was tested by performing three sequential typings of 60 strains of Cl. perfringens. No variation was found in 73% of the strains, while a further 16% of the strains demonstrated a change in sensitivity to only one bacteriocin. Common serological types of Cl. perfringens were divisible into subtypes based upon both their ability to produce bacteriocins and their sensitivity to bacteriocins, suggesting a useful role for bacteriocin typing in conjunction with an already well-established tool for typing Cl. perfringens.

Typing of brucella strains isolated in Iran

Abstract: The results of typing of various strains of Bruc:eUa isolated in a decade, starting 1971, are reported. Isolates of Bruc:eUa abortus were of biotypes 1,2,3,4,5,6,8,9,. Bietype 3 heing considered as the endemic one and biotypes 5 and 9 the most prevalent, next to biotype 3. Bruc:eUa abortus biotype 7 has never heen isolated. Bruc:eUa melitensis biotypes 1 and 2 were mostly isolated from sheep, goats, and even from cattle, of the infected areas. Biotype 3 comprised a small portion of the isolates. The isolates from pigs were shown to he mainly biotype 1 and a few biotype 2 of Bruc:eUa suis. Bruc:eUa canis and Bruc:eUa ovis, which had not heen reported in Iran, were not isolated.

Rapid typing of herpes simplex virus based on immunological specificity of viral thymidine kinase and typing according to sensitivity to iododeoxyuridine.

Abstract: We describe two methods for typing of herpes simplex virus (HSV). One procedure is based on the finding that the multiplication of HSV type 1 strains in primary rabbit kidney cells is inhibited by 2 x 10(-5) M iododeoxyuridine, whereas growth of HSV type 2 strains is considerably less affected. Forty-nine different HSV isolates were typed according to this method. For all isolates except two the results were found to be in agreement with results obtained by another typing procedure, the counterimmunoelectroosmophoretic method (S. Jeansson, Appl. Microbiol. 24:96-100, 1972). One HSV type 1 isolate behaved as a type 2 strain and was found to be a deoxythymidine kinase-negative mutant strain. The other deviant strain exhibited an intermediate iododeoxyuridine sensitivity, thus being impossible to type with this method. Another, faster typing procedure which is based on the immunological difference between HSV type 1 and 2 deoxythymidine kinase is also presented. This assay, in combination with the conventional methods for isolation, enables the detection of deoxythymidine kinase-negative therapy-resistant HSV strains. Finally, we report the detection and typing of HSV deoxythymidine kinase present in vesicle fluids.

Membrane Keyboards and Human Performance

Abstract: Membrane switch technology has become increasingly popular in many consumer-oriented products due to its low production cost and design flexibility. However, the absence of familiar key travel associated with membrane switches removes an important, direct source of feedback to the user with respect to specific keystrokes. Hence, the conventional wisdom has been that membrane switches without key travel are unacceptable for keyboard applications such as typing tasks.This paper describes systematic human factors research in which typing performance using a commercially available membrane keyboard and a conventional, full-travel keyboard was compared for subjects representing different levels of typing proficiency. Each subject (N = 21) used a membrane keyboard for 3 consecutive (or nearly consecutive) days and a conventional keyboard for 3 consecutive (or nearly consecutive) days. Each day of experience consisted of a one-hour session in which various typing exercises were completed. Traditional tests of ty...

Development of sensitive and enzyme-linked immunoassays for herpesvirus antigens and some applications.

Abstract: Sensitive enzyme-linked immunoassays for herpes simplex virus (HSV), cytomegalovirus (CMV) and varicella-zoster virus (VZV) were developed. Both a sandwich technique, using antiviral antibodies from two species to detect the antigen, and an inhibition assay where the sample antigen was incubated with one antiserum, could be used. Around 4-50 ng of viral antigens (measured as protein content) could be detected. The ELISA inhibition technique using type-specific antisera could differentiate between HSV-1 and HSV-2 strains. These could also be distinguished in clinical samples. For CMV, both early and late antigens could be measured as well as the antigenic activity of CMV DNA polymerases. CMV activity in clinical specimens could be detected. The inhibition technique for VZV antigen determination appeared suitable for direct typing of clinical material. No cross-reaction with HSV was seen.

Biotype-Specific Restriction and Modification of DNA in Vibrio cholerae

Abstract: By using Vibrio cholerae typing phages it was possible to demonstrate that within V. cholerae of the O-1 serotype there are at least two biotype-specific DNA restriction and modification systems.

The estimation of gene frequency, based on a particular mixed leukocyte culture experiment.

Abstract: In the treatment of leukemia and aplastic anemia, increasing use is being made of bone marrow transplantation. The feasibility of such transplants depends on the existence of a compatible donor whose marrow cells can be used to repopulate the patient's marrow after its destruction by chemotherapy or radiation. This compatibility is determined by laboratory typing of those loci in the major histocompatibility complex which constitute the human leukocyte antigen (HLA) system. I:)ogs are frequently used as experimental animals in the study of bone marrow transplantation. In dogs the analog of the HLA system is the dog leukocyte antigen (DLA) system. The understanding of the DLA system is, however, much less complete than that of the HLA system. Four gene loci, denoted A, B, C and D, have been identified in the DLA system. This paper is concerned with the D locus and the estimation of gene frequencies for the alleles associated with that locus. A number of alleles have been identified previously by various laboratories and additional alleles have been identified recently at the Fred Hutchinson Cancer Research Center. For a total of 13 alleles, homozygous typing cells have been obtained from dogs shown to be homozygous by family studies. In a mixed leukocyte culture (MLC), responder leukocytes from a dog for which the DLA-D typing is unknown are stimulated by irradiated leukocytes from the panel of homozygous typing cells. The absence of proliferation indicates the presence of the allele typed for by a pa'rticular typing cell in the dog being tested. If a dog's leukocytes do not respond to two typing cells then the phenotype is known. If only one typing cell does not induce proliferation then the dog may be homozygous or heterozygous with the second allele being one for which a typing cell is not in the panel. Homozygosity could be determined by reversing the stimulator and responder cells but for practical reasons this is not done routinely. In laboratories at the Fred Hutchinson Cancer Research Center, 157 dogs from the King County animal shelter were typed against a panel of 13 typing cells. An objective of

Quantitative antibiogram as a potential tool for epidemiological typing.

Abstract: Forty stock, sink drain and clinical isolates of gram-negative bacilli were tested by broth microdilution against eight aminoglycoside antibiotics. Results show that quantitative antibiograms provide more information as epidemiological tools than qualitative antibiograms.

Typing for RhLA—D in Rhesus monkeys: I. characteristics of ten groups of homozygous typing cells1

Abstract: Certain characteristics of 38 homozygous typing cell (TC's) of rhesus monkeys were determined. These TC's define ten RhLA-D locus specificities. Eight of them are associated with established RhLA-DR antigens. Two other groups of typing cells, D9 and D10, were previously considered to be associated with "blank" antigens of the DR series; they now appear to be associated with B-cell antigens which are also likely to be controlled by the DR locus. No influence of RhLA-A or B antigens of MLC reactivity was observed. It was shown, however, that products of at least one locus other than D/DR is responsible for MLC stimulation. Whether those MLC antigens are associated with serologically identifiable B-cell antigens which are not controlled by the DR locus, is not yet clear.

A Bacteriocin Typing Scheme for Bacteroides

Abstract: Summary Epidemiological studies of Bacteroides spp. have been hindered because a suitable typing method is not available. In preliminary studies, 50 strains of Bacteroides were screened against each other for bacteriocin production and sensitivity; 54% of them produced bacteriocin(s) and more than 90% were sensitive to at least one bacteriocin. After calculation of similarity values for these 50 isolates, a typing set of six bacteriocinogenic strains was selected for a typing method based on bacteriocin sensitivity. With this typing set c. 90% of strains could be typed and tests of reproducibility suggested that acceptable accuracy and discrimination could be obtained without applying any one-reaction or two-reaction difference rules. Isolates from four hospitals gave a similar spectrum of typing patterns with 18 bacteriocin types being demonstrated. There was no correlation between bacteriocin type and species of Bacteroides. Repeat isolates from the same patient gave identical typing patterns.

Host specificity of Salmonella weltevreden typing phages.

Abstract: The host range of the six S. weltevreden typing phages was studied on 1469 strains belonging to 37 different Salmonella serotypes. In addition to S. weltevreden, only S. nchanga, S. give, S. lexington and S. anatum, all belonging to O group E, showed varying degrees of susceptibility to the action of some of the typing phages. Typing phage VI lysed only one strain other than S. weltevreden. All serotypes tested other than S. weltevreden were resistant to phages III and IV even at 1000 times the routine test dilution. Thus, typing phages III and IV were specific for S. weltevreden. The sensitivity patterns of S. weltevreden typing phages were not found to bear much correlation with either somatic of flagellar antigens of Salmonellae.

[Coagulase-negative Staphylococci isolated from patients. III. Phage typing].

Abstract: Coagulase-negative staphylococci of clinical origin were subjected to phage typing by means of phages from the experimental Dutch (Verhoef) and American (Paris) sets. These sets of phages were used to study 153 and 378 strains, respectively. The Dutch phages could lyse 30.1%, and the American ones 19.6% of the cultures. The strains belonging to the species S. epidermidis were lysed in 34.3% and 32.4% of cases, respectively, which is indicative of the fact that the American phages possess a more pronounced specificity in respect to S. epidermidis. The unsufficient effectiveness of typing phages does not yet allow one to evaluate the outlook for the method of phage typing in the study of coagulase-negative staphylococci.

Rapid identification and typing of herpes simplex virus in clinical specimens by a direct microneutralization test.

Abstract: Now that various drugs for treating patients suffering from herpes simplex virus (HSV) infections are available (I, 3, 5, 6, 11), it is desirable to give a quick and accurate diagnosis by a method feasible for clinical laboratories. It is also necessary to determine the type of HSV to trace the route of infection as well as to accumulate data for epidemiological analysis. Isolation of the virus from patients followed by a microneutralization test for viral identification and typing (8, 12), if performed within a short period of time, would serve these purposes. The isolation rate seems to be nearly 100% when a suitable transport medium and adequate cells are used (9). However, in this procedure, we have to spend days for preparation of monolayer cultures of an appropriate cell age, observation of cytopathic effect (CPE) and the final neutralization test. To shorten the whole process, we used the clinical specimens directly in a microneutralization test in parallel with conventional cell inoculation. The results were satisfactory in that more than 90% of the isolation-positive specimens could be identified within 3 days by means of the direct assay. Outpatients visiting the Department of Dermatology, Tokyo Women's Medical College, suspected of having herpetic infections were examined by applying a skin swab to the lesion. Just before use, the swab was soaked in divalent cation-free phosphate buffered saline (2) containing 1,000 p,g of streptomycin and 5,000 units of penicillin per ml. After rubbing the lesion, the swab was quickly squeezed into 2 ml of a transport medium which consisted of either Earle's saline plus 0.5% lactalbumin hydrolysate and 0.1 % yeast extract or Eagle's minimum essential medium (MEM) supplemented with 0.11 % NaHCOa and 20% inactivated calf serum. The tube was rubber-stoppered and kept frozen until tested. The suspension was thawed only once and passed through a Millipore membrane of 0.45-p, porosity. No special pretreatment to prevent viral adsorption to the membrane was necessary in this case (8). In most cases, the direct assay was performed simultaneously with inoculation of cells according to the conventional procedure. In the direct assay, the clinical

Short articles a bacteriocin typing scheme for bacteroides

Abstract: SUMMARY. Epidemiological studies of Bacteroides spp. have been hindered because a suitable typing method is not available. In preliminary studies, 50 strains of Bacteroides were screened against each other for bacteriocin production and sensitivity; 54% of them produced bacteriocin(s) and more than 90% were sensitive to at least one bacteriocin. After calculation of similarity values for these 50 isolates, a typing set of six bacteriocinogenic strains was selected for a typing method based on bacteriocin sensitivity. With this typing set c. 90% of strains could be typed and tests of reproducibility suggested that acceptable accuracy and discrimination could be obtained without applying any one-reaction or two-reaction difference rules. Isolates from four hospitals gave a similar spectrum of typing patterns with 18 bacteriocin types being demonstrated. There was no correlation between bacteriocin type and species of Bacteroides. Repeat isolates from the same patient gave identical typing patterns.