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R Hollis

Publications and source records attributed to R Hollis.

26 records · Page 2Linked to original sources
PubMed1989

18q21 rearrangement in diffuse large cell lymphoma: incidence and clinical significance.

Cytogenetic, molecular genetic and clinical information was collected for 102 cases of diffuse large cell lymphoma (DLCL) ascertained in a diagnostic laboratory over a 3-year period. Nineteen cases showed evidence of either a t(14;18) or a rearrangement of one of three genomic probes for breakpoints at 18q21. Clinical and histologic evidence of transformation from follicular lymphoma or chronic lymphocytic leukaemia was available in six cases. Except for age, prognostic clinical variables (LDH, stage, extranodal involvement) were similar between the 18q21 rearranged patients and DLCL patients without 18q21 rearrangement. At a median follow-up in excess of 2 years for both groups, there was no difference in overall survival between the 18q21 rearranged group compared to DLCL patients lacking this genetic abnormality. The median disease-free survival for the 18q21 rearranged group, however, was significantly shorter and survival in partial remission longer. The propensity for extended survival of the 18q21 rearranged DLCL patients with residual or recurrent disease resembled the clinical behaviour of nodular lymphoma patients with t(14;18). These results suggest that cytogenic or molecular genetic identification of a chromosome 18q21 translocation may be of prognostic significance in the analysis of treatment protocols for patients with DLCL.

Adult↗
PubMed1986

The chromosome breakpoint at 14q32 in an ataxia telangiectasia t(14;14) T cell clone is different from the 14q32 breakpoint in Burkitts and an inv(14) T cell lymphoma.

The T cell receptor alpha chain gene locus and the immunoglobulin heavy chain gene locus (IgH) have previously been mapped to the q11 and q32 positions respectively of the human chromosome 14. Both of these sites are also common breakpoints in lymphocytes from ataxia telangiectasia (A-T) patients. Using in situ hybridisation we show that the 14q32 breakpoint in an A-T non-leukaemic T cell clone with t(14;14) translocation, lies outside the IgH locus and proximal to it with respect to the centromere. The 14q11-14qter segment of the homologous chromosome 14 carrying the constant gene region of the alpha chain locus is translocated to this 14q32 position.

Ataxia Telangiectasia↗
PubMedDate not supplied

The application of molecular and immunologic techniques to study the epidemiology of Legionella pneumophila serogroup 1.

We applied monoclonal antibody typing and restriction endonuclease analysis of plasmid DNA to study 28 clinical and 35 environmental (potable water) isolates of Legionella pneumophila serogroup 1 from three hospitals in Iowa between 1981 and 1986. Monoclonal antibody typing employed a panel of seven antibodies and delineated eight different subtypes. Plasmids were present in 57% of the isolates including 12 of 28 (43%) clinical and 25 of 35 (69%) potable water isolates. The plasmids ranged in size from 28 to 98 kilobase pairs and comprised eight distinct subtypes by restriction endonuclease analysis with Eco RI. Combination of monoclonal antibody and restriction endonuclease subtyping (composite subtyping) revealed 19 different composite subtypes of Legionella pneumophila serogroup 1. The most common composite subtype, 09:04, comprised 29% (18 of 63) of the isolates and was only found in clinical and potable water samples from a single pavilion in hospital A during an outbreak of Legionella pneumophila serogroup 1 pneumonia. Aside from this cluster the diversity of composite subtypes of Legionella pneumophila serogroup 1 observed in clinical and potable water sources over the 5-year period was striking. The combination of monoclonal antibody and restriction endonuclease typing resulted in improved strain delineation and a more useful use of epidemiologic markers for Legionella pneumophila serogroup 1.

Antibodies, Monoclonal↗
PubMedDate not supplied

The use of biotyping and DNA fingerprinting in typing Candida albicans from hospitalized patients.

The application of typing procedures for the purpose of strain differentiation among isolates of Candida albicans obtained from hospitalized patients has been limited. We have applied biotyping and DNA restriction fragment analysis (DNA fingerprinting) by using EcoRI to the study of C. albicans isolates obtained from hospitalized patients. A total of 68 isolates from 15 patients were studied. Thirteen subtypes were identified by biotyping, 8 by DNA fingerprinting, and 21 by a combination of the biotyping and DNA fingerprinting approaches (composite subtype). Both techniques were highly reproducible. In examining the strain variation among isolates obtained from multiple anatomic sites over time, we found that similar, if not identical, strains were recovered from the oropharynx, urine, stool, and blood in a given patient, and these strains persisted. Only rarely did two patients share the same composite subtype suggesting sporadic nosocomial transmission. The combination of biotyping and DNA fingerprinting improved strain discrimination compared to either method alone. Further investigation with these and other epidemiologic typing methods will be necessary to enhance the understanding of the epidemiology and pathogenesis of candidiasis in hospitalized patients.

Bacterial Typing Techniques↗
PubMedDate not supplied

The clinical microbiology laboratory as an aid in infection control. The application of molecular techniques in epidemiologic studies of methicillin-resistant Staphylococcus aureus.

A microbiologic surveillance study was performed in order to estimate the point prevalence, source, and nosocomial acquisition of methicillin-resistant Staphylococcus aureus (MRSA) within the Iowa City Veterans Affairs Medical Center (IC VAMC). Immediately following the microbiologic surveillance study, a cluster of nosocomial MRSA infections was detected by routine infection control surveillance. An epidemiologic investigation was conducted and all isolates of MRSA detected during the microbiologic surveillance study and the subsequent cluster of nosocomial infections were characterized by restriction endonuclease analysis of plasmid DNA (REAP). REAP subtyping defined a total of ten distinct subtypes from 24 patients infected or colonized with MRSA. The documentation of a single subtype of MRSA (subtype A2) in nine patients from the surgical service, eight of which were hospitalized in the surgical intensive care unit, provided convincing evidence of a breakdown of infection control practices in that unit. REAP subtyping was a highly discriminating means of identifying different subtypes among the various isolates of MRSA and was useful in directing infection control efforts to specific problem areas within the hospital. Molecular typing methods, such as REAP, when used appropriately in conjunction with careful epidemiologic investigation provide an effective approach to the investigation and control of the spread of MRSA within the hospital.

Clindamycin↗
PubMedDate not supplied

Application of restriction endonuclease analysis of chromosomal DNA in the study of Staphylococcus aureus colonization in continuous ambulatory peritoneal dialysis patients.

The relationship between nasal and skin colonization with Staphylococcus aureus and subsequent infection in continuous ambulatory peritoneal dialysis (CAPD) patients in Brazil has been documented by restriction endonuclease analysis of plasmid DNA. However, S. aureus strains without detectable plasmids have been identified. Using restriction endonuclease analysis of chromosomal DNA hybridized with an rRNA gene probe, we document the diversity of S. aureus strains without detectable plasmids colonizing CAPD patients. Ten paired strains without detectable plasmids from five patients were studied by restriction endonuclease analysis of chromosomal DNA and by phage typing. Five different profiles were obtained by restriction endonuclease analysis of chromosomal DNA. Although four of the ten paired isolates were nontypeable by phage typing, all were discriminated by restriction endonuclease analysis of chromosomal DNA. These results demonstrate that restriction endonuclease analysis of chromosomal DNA is a useful epidemiologic tool and complements the restriction endonuclease analysis of plasmid DNA of S. aureus by providing a means of typing strains without detectable plasmids.

Bacteriophage Typing↗