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Biomedical subjects

D H Persing

Publications and source records attributed to D H Persing.

At least 73 records · Page 4Linked to original sources
PubMed1999

Infection, immunity, and cancer.

A significant percentage of human cancers worldwide are associated with infections due to known viruses, including human papillomaviruses (cervical cancer and other skin cancers), human T-lymphotropic viruses (adult T-cell leukemias and lymphomas in endemic areas), hepatitis B virus (liver cancer), and Epstein-Barr virus (Burkitt lymphoma and nasopharyngeal carcinoma). The fraction of human cancers attributable to infection may now need to be revised in light of the fact that new viral associations have been discovered and other nonviral associations have been identified. This article addresses the increasingly recognized role of infectious agents as precipitants of human neoplasia and the possibility that novel diagnostic, therapeutic, and chemopreventive strategies may emanate directly from research directed at identifying and understanding these agents.

Adult↗
PubMed1998

Persistent parasitemia after acute babesiosis.

BACKGROUND: Babesiosis, a zoonosis caused by the protozoan Babesia microti, is usually not treated when the symptoms are mild, because the parasitemia appears to be transient. However, the microscopical methods used to diagnose this infection are insensitive, and few infected people have been followed longitudinally. We compared the duration of parasitemia in people who had received specific antibabesial therapy with that in silently infected people who had not been treated. METHODS: Forty-six babesia-infected subjects were identified from 1991 through 1996 in a prospective, community-based study designed to detect episodes of illness and of seroconversion among the residents of southeastern Connecticut and Block Island, Rhode Island. Subjects with acute babesial illness were monitored every 3 months for up to 27 months by means of thin blood smears, Bab. microti polymerase-chain-reaction assays, serologic tests, and questionnaires. RESULTS: Babesial DNA persisted in the blood for a mean of 82 days in 24 infected subjects without specific symptoms who received no specific therapy. Babesial DNA persisted for 16 days in 22 acutely ill subjects who received clindamycin and quinine therapy (P=0.03), of whom 9 had side effects from the treatment. Among the subjects who did not receive specific therapy, symptoms of babesiosis persisted for a mean of 114 days in five subjects with babesial DNA present for 3 or more months and for only 15 days in seven others in whom the DNA was detectable for less than 3 months (P<0.05); one subject had recrudescent disease after two years. CONCLUSIONS: When left untreated, silent babesial infection may persist for months or even years. Although treatment with clindamycin and quinine reduces the duration of parasitemia, infection may still persist and recrudesce and side effects are common. Improved treatments are needed.

Animals↗
PubMed1998

Hepatitis G virus infection in patients transplanted for cryptogenic cirrhosis: red flag or red herring?

BACKGROUND: The significance of hepatitis G (HGV) infection in liver transplant recipients is not known. We set out to determine the pre-orthotopic liver transplantation (OLT) prevalence, the pre- and postoperative viral titers of HGV, and the allograft histology in patients infected with HGV who underwent OLT for cryptogenic cirrhosis. METHODS: HGV RNA was measured using a research-based branched DNA assay. The assay used a target-specific probe set that was based on the 5'-untranslated region of the HGV genome. Allograft histology was assessed with protocol liver biopsies in all patients who survived longer than 6 months. RESULTS: The preoperative prevalence of HGV infection in recipients transplanted for cryptogenic cirrhosis was 26%. Thirty-seven percent (12 of 33) of recipients who had serum available in the first postoperative month had HGV infection. Mean HGV RNA levels were 9.8 (+/-4.2) (viral molecular equivalents/ml x 10[6]) before OLT and 37.5 (+/-10.7) at 1 year after OLT. In 4 of the 11 cryptogenic recipients in whom HGV RNA was detectable in the first postoperative month, HGV RNA fell to undetectable levels at the most recent follow-up (mean 70 months). Of the five cryptogenic recipients who continue to have measurable HGV RNA, three have unexplained hepatitis histologically. CONCLUSIONS: These findings suggest the following: 1) The prevalence of HGV infection in patients undergoing OLT for cryptogenic cirrhosis is about 25%. 2) In recipients persistently infected with HGV, mean HGV RNA titers increase after OLT. 3) HGV RNA becomes undetectable in about one third of recipients who had detectable HGV RNA in the first month after OLT. 4) Hepatitis of uncertain etiology occurs in 60% (3 of 5) of persistently HGV-infected cryptogenic recipients.

Adult↗
PubMed1998

Ocular manifestations of Whipple disease: an atypical presentation.

A 62-year-old man developed bilateral granulomatous iridocyclitis after uncomplicated cataract surgery. On ophthalmic examination, we found moderate inflammation in the anterior chamber and vitreous, with granular crystalline deposits on the iris, intraocular lens, and capsular bag. Biopsy of the lens capsule and vitreous revealed periodic acid-Schiff-positive, diastase-resistant bacilli consistent with Tropheryma whippelii. Electron microscopy and polymerase chain reaction confirmed the diagnosis of Whipple disease. A jejunal biopsy specimen also revealed T whippelii. Treatment with trimethoprim-sulfamethoxazole, cefixime, rifampin, and doxycycline resulted in improvement of systemic symptoms, but intraocular inflammation persisted. Intraocular inflammation was eventually reduced with the intravenous administration of ceftriaxone sodium.

Actinobacteria↗
PubMed1998

Reverse transcriptase-polymerase chain reaction fails to detect peripheral-blood hepatitis C RNA in formalin-fixed liver tissue.

Currently, one of the major indications for liver transplantation is infection with hepatitis C virus (HCV). Many studies have suggested that recurrent infection with HCV is universal after transplantation. Fastidious techniques, such as reverse transcriptase-polymerase chain reaction (RT-PCR), have proved to be highly sensitive for detecting HCV RNA in serum and in fresh-frozen and formalin-fixed paraffin-embedded (FFPE) liver tissue. In this study, we wanted to determine whether the identification of HCV RNA in liver tissue by RT-PCR might reflect the detection of circulating HCV RNA in blood within the tissue, rather than implying true tissue infection. We performed RT-PCR for HCV RNA in FFPE liver biopsy specimens taken from 14 donor allografts shortly before and immediately after implantation into recipients. The recipients were known to have HCV RNA in serum and explanted liver tissue, as determined by RT-PCR. We were unable to detect HCV RNA in any of the study samples, either before or after transplantation. In a related study, qualitative and quantitative HCV RNA analyses were performed by RT-PCR and branched DNA (bDNA) amplification, respectively, on serum samples collected pretransplantation and immediately posttransplantation from 10 other patients who underwent transplantation for hepatitis C. HCV RNA was detected in all serum samples before and after transplantation by RT-PCR; however, the bDNA assay detected HCV RNA in only 6 of 10 samples pre-orthotopic liver transplantation (OLT) and in none of the immediately post-OLT samples. In our system, despite the RT-PCR detection of HCV RNA in serum before and after the transplantation, HCV RNA is not detectable in the peripheral blood that accompanies formalin-fixed liver tissue. This implies that RT-PCR detection of HCV RNA in tissue reflects true liver infection, rather than contamination by HCV RNA in accompanying peripheral blood.

Formaldehyde↗
PubMed1998

Cervical cancer in older women: a molecular analysis of human papillomavirus types, HLA types, and p53 mutations.

OBJECTIVE: The purpose of this study was to evaluate cervical cancers in older women to determine whether they differed from tumors in younger women with respect to human papillomavirus types, frequencies of p53 mutations, and presence of a proposed high-risk HLA-DR2 haplotype. STUDY DESIGN: Cervical tissue was obtained from women undergoing surgical treatment of in situ or invasive carcinoma of the cervix. Viral and genomic deoxyribonucleic acid was extracted. The presence of human papillomavirus deoxyribonucleic acid was detected by polymerase chain reaction amplification. Viral subtypes were assigned by means of a combination of type-specific amplification and automated sequencing of the L1 region. The presence of p53 mutations was evaluated by direct sequencing of exons 5 through 9. The HLA-DR locus was screened for the presence of the high-risk DRB1*1501 allele by means of selective polymerase chain reaction amplification followed by agarose gel electrophoresis of HLA-DR2 types. RESULTS: Tumors from 39 women 62 to 85 years old were analyzed. Tumors from 104 younger women formed a reference group. Human papillomavirus 16 was found in 41% and 54% and human papillomavirus 18 was found in 10% and 12% of the tissue samples from older and younger women, respectively. The overall distributions of human papillomavirus types did not differ statistically between the groups. One of the 25 older patients tested had a p53 mutation. This tumor also had a positive test result for human papillomavirus 18. The DR*1501 allele was present in 33% of the older patients and 28% of the younger patients. The expected frequency of this allele in white Americans is 19.8%. The increased frequency of this allele among both older and younger women with cervical cancer was statistically significant (P < .05). CONCLUSIONS: We hypothesized that cervical cancer in older women might differ from that in younger women with respect to human papillomavirus types, natural host immunity, or the frequency of nonviral origins of the cancer. The findings show, however, that tumors from older women are extremely similar to those from younger women with respect to the human papillomavirus types present and the infrequent occurrence of p53 mutations. In addition we found that an HLA-DR allele that is associated with a risk of cervical cancer in younger women is also associated with risk in older women. These findings are most consistent with a model similar to that in younger women but with an unusually long latency for the transforming effect of the virus in some hosts.

Aged↗
PubMed1998

Coinfection with Babesia microti and Borrelia burgdorferi in a western Wisconsin resident.

A 68-year-old woman, who had not traveled outside of western Wisconsin, was hospitalized after 4 weeks of chills, fevers, myalgias, neuralgias in her right arm, and pain in the right upper quadrant of her abdomen. Physical examination revealed hepatosplenomegaly, and laboratory studies showed anemia, thrombocytopenia, increased aspartate transaminase level, and microscopic hematuria. Wright's stain of a blood smear revealed intraerythrocytic organisms consistent with Babesia species. A polymerase chain reaction of whole blood specimens along with an increased serologic titer confirmed the diagnosis of Babesia microti. Indirect immunofluorescent antibody serology and Western blot analysis revealed a simultaneous infection with Borrelia burgdorferi. Coinfection with B. microti and B. burgdorferi may occur in endemic areas where both organisms are carried by the same tick vector, Ixodes scapularis. The intensity and duration of illness seem to be greatest in patients with concurrent infection.

Aged↗
PubMed1998

GB virus-C infection in type 1 autoimmune hepatitis.

OBJECTIVE: To assess the frequency and significance of GB virus-C infection in type 1 autoimmune hepatitis. MATERIAL AND METHODS: Serum specimens from 94 patients with type 1 autoimmune hepatitis were tested for GB virus-C RNA by reverse transcription and polymerase chain reaction. Serum samples from 50 normal subjects were also assessed. RESULTS: Three of the 94 specimens from patients with autoimmune hepatitis were positive for GB virus-C RNA in comparison with none of the 50 control samples (3% versus 0%; P = 0.5). Two patients were seropositive after variceal hemorrhage and blood transfusion, including one patient who clearly acquired the infection in this fashion. One patient had no epidemiologic basis for his seropositivity. Viremia was prolonged in all infected patients (mean duration, 69 +/- 23 months; range, 36 to 113); however, no clinical features suggested a concurrent viral infection, and mortality was similar to that among the uninfected counterparts (33% versus 8%; P = 0.2). Liver transplantation was more common in the infected patients (67% versus 9%; P = 0.03), but the duration of disease was also longer in these patients (277 +/- 29 months versus 106 +/- 9 months; P = 0.0008). Clinical features and immediate responses to corticosteroid therapy were similar in both groups. CONCLUSION: GB virus-C RNA is found infrequently in type 1 autoimmune hepatitis, and GB virus-C is unlikely to be an important etiologic agent or prognostic determinant.

Biopsy, Needle↗
PubMed1998

Immunoserologic evidence of Human Granulocytic Ehrlichiosis in Danish patients with Lyme neuroborreliosis.

Human Granulocytic Ehrlichiosis (HGE) is a recently described human illness in the US which manifests as fever, myalgia and headache combined with pancytopenia and elevated concentrations of hepatic transaminases. Genetic analyses indicate that the agent of HGE appears to be an Ehrlichia species that is closely related to E. equi and E. phagocytophila. Ixodes dammini and I. scapularis were identified as potential vectors of HGE. Ixodes ticks are also the vector of Borrelia burgdorferi, the agent of Lyme borreliosis. The presence of antibodies against Ehrlichia in 132 sera from Danish patients with definite Lyme neuroborreliosis were examined in order to provide immunoserologic evidence of this infection in Denmark. Patients with Lyme neuroborreliosis were chosen as a test cohort, as these patients had been infested by a tick sufficient for transmission of B. burgdorferi. All had cerebrospinal fluid lymphocytic pleocytosis. As controls, serum samples from 50 healthy Danish blood donors were included. Of the 132 patients with Lyme neuroborreliosis, 5 (3.8%) reacted with the E. equi antigen substrate at titres 1:128. None of the blood donors were found seropositive for E. equi. At least 2 of the patients found seropositive for HGE constituted probable cases of HGE with E. equi antibody titres of at least 80 combined with fever, headache and myalgias. However, in no cases were we able to detect the presence of the HGE agent in the serum by PCR. We conclude that human exposure to granulocytic Ehrlichiae species may also occur in Europe, although further studies will be necessary to document active infection with these potential pathogens.

Adult↗
PubMed1998

Cosegregation of a novel Bartonella species with Borrelia burgdorferi and Babesia microti in Peromyscus leucopus.

During surveillance for various tickborne pathogens in the upper Midwest during the summer and early fall of 1995, a Bartonella-like agent was detected in the blood of mice that were concurrently infected with Borrelia burgdorferi or Babesia microti (or both). The organism was isolated in pure culture after inoculation of blood from wild-caught mice into C.B-17 scid/scid mice. Phylogenetic analysis of the 16S rRNA and the citrate synthase genes showed that the novel Bartonella species and a Bartonella isolate from a mouse captured on Martha's Vineyard, Massachusetts, were closely related to each other and secondarily related to Bartonella grahamii and Bartonella vinsonii. Further analysis of Peromyscus leucopus blood and tissue samples demonstrated that the novel Bartonella species was exclusively found in conjunction with B. burgdorferi and B. microti. Patent coinfection with these agents may be relatively frequent in naturally infected mice.

Animals↗
PubMed1998

Fatal pancarditis associated with human granulocytic Ehrlichiosis in a 44-year-old man.

Human cases of infection with a granulocytotropic Ehrlichia species closely related to Ehrlichia equi are now being described with increasing frequency in the United States, especially in areas where Lyme disease is already endemic. We describe a case of fatal pancarditis during the course of human granulocytic ehrlichiosis (HGE) in a 44-year-old outdoor worker who was previously treated for presumptive Lyme disease. Serological and molecular diagnostic tests for Borrelia burgdorferi and Babesia microti infections were negative. Postmortem serum specimens were seroreactive for HGE, and molecular evidence of infection with the HGE agent was obtained. These findings suggest that carditis may be a manifestation of HGE, further complicating the differential diagnosis of tick-borne illness.

Adult↗
PubMed1998

Evaluation of a polymerase chain reaction-based universal heteroduplex generator assay for direct detection of rifampin susceptibility of Mycobacterium tuberculosis from sputum specimens.

In a double-blind study, 655 sputum specimens were obtained from individuals suspected of having tuberculosis and were analyzed for the presence of Mycobacterium tuberculosis and rifampin susceptibility with use of a polymerase chain reaction (PCR)-based universal heteroduplex generator assay (PCR/UHG-Rif). Of the specimens containing viable M. tuberculosis, 100% of the smear-positive (n = 41) and 50% of the smear-negative (n = 6) specimens tested positive for the organism by PCR/UHG-Rif. Nineteen of 537 culture-negative specimens tested positive for M. tuberculosis by PCR/UHG-Rif and were from patients with confirmed tuberculosis who were receiving antituberculosis therapy at the time of specimen collection. Thirty-five specimens contained nontuberculous mycobacteria and were negative by PCR/UHG-Rif. Genotypic evidence of rifampin resistance in five of six culture-confirmed, rifampin-resistant isolates was obtained by PCR/UHG-Rif, yielding a sensitivity and specificity for the assay of 83% and 98.2%, respectively. These results demonstrate the feasibility of using a PCR-based assay directly on sputum specimens for simultaneous detection of M. tuberculosis and rifampin susceptibility, and they suggest that patients with smear-positive, untreated tuberculosis and those presenting with suspected drug-resistant tuberculosis are the most appropriate groups for testing by PCR/UHG-Rif.

Antibiotics, Antitubercular↗
PubMed1998

Bordetella holmesii-like organisms associated with septicemia, endocarditis, and respiratory failure.

We recovered an unusual bacterial strain from blood or sputum of three patients with septicemia, endocarditis, and/or respiratory failure. The three isolates were thin, curved, gram-negative, light brown, pigment-producing bacilli with variable catalase activity. They were asaccharolytic, oxidase-negative, nonmotile, and fastidious. Identification was not possible on the basis of these characteristics alone or in combination with cellular fatty acid profiles. Nucleic acid amplification and sequence analysis of the 16S rRNA gene revealed that all three isolates were identical and most closely related to the emerging pathogen Bordetella holmesii, diverging from the published sequence at three nucleotide positions (99.8% similarity). Isolation of a B. holmesii-like pathogen from sputum suggests that, in addition to producing septicemia, the organism may inhabit the respiratory tract like other Bordetella species.

Adolescent↗
PubMed1998

Differential effects of infection with a Babesia-like piroplasm, WA1, in inbred mice.

A newly identified intraerythrocytic Babesia-like organism, WA1, and its relatives were recently shown to be infectious for humans in the western United States. The purpose of the present study was to determine the susceptibilities of selected mouse genotypes to WA1 infection in an attempt to develop a murine model of the human disease. Several mouse strains were inoculated intraperitoneally with various passages of WA1-parasitized erythrocytes. Parasitemia was evaluated by blood smears and by PCR with blood samples collected at various intervals after inoculation. Hematologic parameters were monitored in blood samples at all intervals. C57BL/6 and C57BL/10 mice exhibited mortality rates of <10%. BALB/cJ, CBAJ, and 129/J mice had higher peak parasitemias than did C57BL mice, with mortality rates of 40, 50, and 50%, respectively. A/J, AKR/N, C3H, and DBA/1J mice also had higher peak parasitemia and mortality rates (>95%). An F1 cross of C57BL/6 (resistant) and C3H.RKK (susceptible) mice had a mortality rate similar to that of the resistant parental strain. Histopathology of BALB/cJ and C3H mice at 9 and 14 days after inoculation revealed erythrophagocytosis and deposition of an iron-negative pigment in multiple organs. Morbidly ill C3H mice at 14 days had severe pulmonary edema, hemoglobinuria, and glomerulonephritis.

Animals↗
PubMed1998

Comparison of phenotypic and genotypic techniques for identification of unusual aerobic pathogenic gram-negative bacilli.

Rapid and accurate identification of bacterial pathogens is a fundamental goal of clinical microbiology, but one that is difficult or impossible for many slow-growing and fastidious organisms. We used identification systems based on cellular fatty acid profiles (Sherlock; MIDI, Inc., Newark, Del.), carbon source utilization (Microlog; Biolog, Inc., Hayward, Calif.), and 16S rRNA gene sequence (MicroSeq; Perkin-Elmer Applied Biosystems Division, Foster City, Calif.) to evaluate 72 unusual aerobic gram-negative bacilli isolated from clinical specimens at the Mayo Clinic. Compared to lengthy conventional methods, Sherlock, Microlog, and MicroSeq were able to identify 56 of 72 (77.8%), 63 of 72 (87.5%), and 70 of 72 (97.2%) isolates to the genus level (P = 0.002) and 44 to 65 (67.7%), 55 of 65 (84.6%), and 58 of 65 (89.2%) isolates to the species level (P = 0.005), respectively. Four Acinetobacter and three Bordetella isolates which could not be identified to the species level by conventional methods were identified by MicroSeq. In comparison to the full 16S rDNA sequences, the first 527 bp provided identical genus information for all 72 isolates and identical species information for 67 (93.1%) isolates. These data show that MicroSeq provides rapid, unambiguous identification of clinical bacterial isolates. The improved turnaround time provided by genotypic identification systems may translate into improved clinical outcomes.

Carbon↗
PubMed1998

Clinical evaluation of the Gen-Probe Amplified Direct Test for detection of Mycobacterium tuberculosis complex organisms in cerebrospinal fluid.

Eighty-four cerebrospinal fluid (CSF) samples from different children who presented with signs and symptoms of meningitis were evaluated for the presence of Mycobacterium tuberculosis complex organisms by the Gen-Probe Amplified Mycobacterium tuberculosis Direct Test (MTD; Gen-Probe, San Diego, Calif.). All CSF samples had negative acid-fast smears by the Ziehl-Neelsen staining method. M. tuberculosis was recovered from five samples. M. tuberculosis did not grow from 19 additional samples, but the samples were from patients who fulfilled specific clinical and laboratory criteria for probable tuberculous meningitis (TBM). The remaining samples (n = 60) were from patients with other infections or noninfectious causes of meningitis. The results of the MTD were interpreted as positive or negative on the basis of recommended cutoff values for respiratory specimens. These results were interpreted as true or false positives or true or false negatives on the basis of the results of M. tuberculosis culture or whether the patient fulfilled criteria for probable TBM. The Gen-Probe MTD was 33% sensitive and 100% specific for detecting M. tuberculosis complex organisms in these 84 CSF samples. If the cutoff values for positive results were decreased for the MTD (> or = 11,000 versus > or = 30,000 relative light units), the sensitivity increased to 83% and the specificity remained 100%. These results for the MTD are encouraging considering that TBM is a highly fatal disease and difficult to diagnose by conventional laboratory techniques.

Adolescent↗
PubMed1998

Branched-DNA assay for detection of the mecA gene in oxacillin-resistant and oxacillin-sensitive staphylococci.

The identification of methicillin-resistant staphylococcus isolates in the clinical laboratory has typically been performed by using methods that detect phenotypic expression of resistance determinants. However, these methods may be difficult to interpret and some isolates do not express resistance until selective pressure is administered. Assays that detect genetic determinants are not subject to these limitations and have been effective in distinguishing isolates that are capable of expressing the resistance phenotype. In this study, a novel branched-DNA (bDNA) hybridization assay was used to test for the mecA gene in 416 clinical staphylococcal isolates. The results were compared with those obtained by a PCR-based assay and oxacillin disk diffusion. For 155 Staphylococcus aureus and 261 coagulase-negative Staphylococcus isolates, the bDNA assay and PCR results were 100% concordant. Among the S. aureus isolates, 20 were MecA+ and 135 were MecA-. For the coagulase-negative staphylococci, 150 were MecA+ and 111 were MecA-. The results from the genotypic detection methods were compared with those obtained by oxacillin disk diffusion. No discrepancies were detected among the S. aureus isolates; however, 10 coagulase-negative isolates were MecA+ but oxacillin sensitive and 1 isolate was MecA- but oxacillin resistant. Oxacillin resistance was induced in 6 of the 10 MecA+ isolates previously classified as oxacillin sensitive. These results suggest that the bDNA method described here is a sensitive and efficient method for detection of methicillin resistance in staphylococci and that genetic detection methods may be useful for detection of potential methicillin resistance in the clinical laboratory.

DNA Primers↗