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Biomedical subjects

J Aslanzadeh

Publications and source records attributed to J Aslanzadeh.

At least 19 recordsLinked to original sources
PubMed2000

Incidence and outcome of vancomycin-resistant enterococcal bacteremia following autologous peripheral blood stem cell transplantation.

A retrospective evaluation of 321 consecutive recipients of high-dose chemotherapy (HDC) and autologous peripheral blood stem cell transplantation (PBSCT) was conducted to ascertain the incidence and outcome of vancomycin-resistant enterococcal (VRE) bacteremia. Ten patients developed VRE bacteremia at a median of 6 days following PBSCT. Nine isolates were Enterococcus faecium and one was E. faecalis. The median duration of bacteremia was 5 days. The central venous catheter was removed in seven individuals. Nine patients were treated with a variety of antimicrobial agents including quinupristin-dalfopristin, chloramphenicol, doxycycline, oral bacitracin, co-trimoxazole, and nitrofurantoin. Bacteremia resolved without adverse sequelae in seven patients. Two individuals who died of other causes had persistent or relapsed bacteremia at the time of death. An additional patient suffered multiple relapses of VRE bacteremia and died as a result of VRE endocarditis 605 days following PBSCT. Mortality as a direct result of VRE bacteremia was 10% in this series. The optimal type and duration of treatment of VRE bacteremia has not been clearly defined. Therefore, we perform weekly stool surveillance cultures for VRE in our hospitalized transplant population and apply strict barrier precautions in those individuals in whom stool colonization has been identified. Furthermore, the empiric use of vancomycin has been restricted. Bone Marrow Transplantation (2000) 25, 147-152.

Adolescent↗
PubMed1999

Cytomegalovirus viremia, viruria and disease after autologous peripheral blood stem cell transplantation: no need for surveillance.

A retrospective evaluation of 200 consecutive recipients of autologous peripheral blood stem cell transplantation (PBSCT) was conducted to ascertain the incidence, risk factors, clinical features, complications, and outcome of cytomegalovirus (CMV) infection. A total of 26 patients (13%) developed CMV viremia (n = 5), DNAemia (n = 3), viruria (n = 18) and/or disease (n = 3) at a median of 45 days following stem cell infusion. None of the patients underwent surveillance testing for CMV. A diagnosis was established by culture and polymerase chain reaction of blood, urine or other tissue samples submitted when patients exhibited clinical features suggestive of CMV infection. Cytomegalovirus seropositivity prior to transplantation was the only statistically significant risk factor predicting subsequent identification of CMV (P < 0.001). The symptoms were severe enough in 23 patients to warrant treatment with intravenous ganciclovir. Three patients developed CMV disease; two developed fatal CMV pneumonia and one developed CMV gastritis which responded to antiviral treatment. Clinical signs and symptoms as well as viremia and viruria resolved with (20 patients) and without (three patients) treatment in the remaining individuals. All instances of CMV viremia, DNAemia, viruria and disease occurred within 3 months of stem cell infusion. These results demonstrate that CMV is a common pathogen after autologous PBSCT and may result in fatality in rare instances. Surveillance programs appear to be neither useful nor cost-effective. Diagnostic evaluation should be performed only in patients exhibiting suspicious clinical features and antiviral chemotherapy should be administered for persistent and severe signs and symptoms.

Adolescent↗
PubMed1999

Southern extension of the range of human babesiosis in the eastern United States.

We sought evidence of babesiosis in three residents of New Jersey who were suspected of local acquisition of Babesia microti infection. We tested serial blood samples from these residents for B. microti antibodies and amplifiable DNA by using immunofluorescent antibody and PCR techniques. All three residents experienced symptoms suggestive of acute babesiosis. The sera of each of the patients reacted against babesial antigen at a titer fourfold or higher in sequentially collected blood samples. PCR-amplifiable DNA, characteristic of B. microti, was detected in their blood. These data suggest that human B. microti infections were acquired recently in New Jersey, extending the range of this piroplasmosis in the northeastern United States.

Adult↗
PubMed1998

Comparison of culture and acid-fast bacilli stain to PCR for detection of Mycobacterium tuberculosis in clinical samples.

The major drawback in effective use of polymerase chain reaction (PCR) for detecting Mycobacterium tuberculosis (MTB) in clinical samples is the presence of PCR inhibitors and unique cell components of the organism that complicate DNA extraction and subsequent PCR amplification. A PCR assay with a unique multistep DNA extraction method that minimizes these problems was compared in a prospective study to acid-fast bacilli stain (AFBS) and culture for detecting MTB in clinical samples. A total of 254 clinical specimens in two separate studies were processed for MTB by these techniques. While PCR and culture were 100% sensitive and specific, culture required up to 8 weeks of incubation and additional time to perform biochemical testing to identify the isolated micro-organism. Acid-fast bacilli stain had a specificity of about 87% and did not differentiate among Mycobacterial species. In contrast, the results from PCR were available within 48 h and did not require additional testing to attain a final result. Polymerase chain reaction was highly reliable for detection and confirmation and interpretation of positive AFBS results. The assay was easy to perform with a turn around time of about 2 days.

Bacteriological Techniques↗
PubMed1996

Evaluation of PCR and nested PCR for laboratory diagnosis of hepatitis C virus infection.

The detection of hepatitis C virus (HCV) RNA by nested polymerase chain reaction (PCR) is believed to be the most reliable method to diagnose HCV infections. A pitfall of nested PCR is that it is prone to contamination. Single step reverse transcription-PCR (RT-PCR) was performed, prospectively, on 80 sera from 59 patients with a set of primers that amplified a 273 bp sequence unique to the 5' noncoding (NC) region of the HCV genome. Nested PCR, was performed on all PCR negative specimens with a set of primers that amplified a 255 bp internal to the original primers. Single step RT-PCR was positive on 45 sera from 35 patients following gel electrophoresis and on two additional sera from two patients following Southern blot hybridization. Nested PCR was positive on two more sera following gel electrophoresis of the nested PCR products. These two patients were seropositive and subsequent serum from one patient was positive by single step PCR. Three additional sera were positive following Southern blot analysis of the nested PCR products. Two patients were seropositive and had elevated serum alanine aminotransferase (ALT) levels. The third patient was seronegative with normal ALT level and was considered a false positive. The remaining seronegative control specimens were PCR negative by both methods. The majority of PCR positive patients (82%) had elevated ALT levels, while the majority of PCR negative seropositive patients had normal ALT levels. We conclude that single step PCR is a sensitive test for the laboratory diagnoses of the majority of the HCV infections.

Animals↗
PubMed1996

Use of AmpliWax to optimize amplicon sterilization by isopsoralen.

The photochemical inactivation of amplicons by isopsoralen (IP-10) has been suggested as a possible means to prevent PCR carryover contamination. To evaluate the technique, serial dilutions of amplicons (10(11) to 10(3)) from the Borrelia burgdorferi OSP A gene were amplified in the presence of 0, 25, 50, and 100 micrograms of IP-10 per ml for 45 cycles. The PCR products were exposed to UV light for 15 min to activate IP-10 and sterilize the amplicons. One microliter of each sterilized sample was reamplified for an additional 45 cycles. The PCR products were then resolved in an agarose gel, blotted onto a nylon membrane, and probed with an alkaline phosphatase-conjugated chemiluminescent probe. Although IP-10 at concentrations of 50 and 100 micrograms/ml effectively sterilized up to 10(11) amplicons, the compound was inhibitory to PCR. IP-10 at a concentration of 25 micrograms/ml had slight inhibitory effect on PCR and did not completely sterilized all of the amplicons. Therefore, in subsequent experiments AmpliWax was substituted for mineral oil, and PCR was performed on 10(9) to 10(3) amplicons as described above. Following the amplification, the PCR tubes were cooled to solidify the AmpliWax and inoculated with various concentrations of IP-10. With this technique, PCR products produced from as many as 10(9) target amplicons were effectively sterilized with 200 micrograms of IP-10 per ml. Similarly, the addition of IP-10 (50 micrograms/ml) before and after PCR was evaluated for the detection of B. burgdorferi in 62 ticks from a region of Southern Connecticut where the organism is highly endemic. PCR performed in the presence of 50 micrograms of IP-10 per ml detected B. burgdorferi-specific DNA in 17 of 62 ticks (27%) following gel electrophoresis and in 34 of 62 ticks (55%) following Southern blot hybridization of the PCR products. In contrast, post-PCR addition of IP-10 detected borrelia-specific DNA in 31 of 62 ticks (50%) following gel electrophoresis and in 46 of 62 ticks (64%) following Southern blot hybridization. We conclude that the replacement of mineral oil with AmpliWax can be useful in eliminating the inhibitory effects of IP-10 and other sterilizing agents for post-PCR sterilization of amplicons.

Animals↗
PubMed1996

Oerskovia xanthineolytica infection of a prosthetic joint: case report and review.

Oerskovia spp. are gram-positive, Nocardia-like bacilli which inhabit the soil and rarely cause human infections. Previously reported cases of Oerskovia infection have been characterized by a nonaggressive course and an association with foreign bodies. We report the first case of a patient with a prosthetic joint infection due to Oerskovia xanthineolytica. Our patient presented with a prolonged, indolent course and was thought to have aseptic loosening of his prosthesis until the time of surgery. He was cured of his infection by removal of the prosthesis, antibiotic therapy, and delayed reimplantation. Review of the previous 10 reported cases of Oerskovia infection in humans supports the recommendation that foreign-body-associated infections should be treated with a strategy that includes removal of the foreign material.

Actinomycetales↗
PubMed1993

Application of hydroxylamine hydrochloride for post-PCR sterilization.

A major problem in the application of polymerase chain reaction (PCR) in diagnostic laboratories is contamination with exogenous nucleic acid, especially aerosolized amplicon, from previous PCR. Although several pre- and post-PCR sterilization techniques have been proposed, an optimal sterilization technique is not yet available. Hydroxylamine hydrochloride is a mutagenic agent that binds to and chemically modifies DNA. In the present study PCR was performed on DNA extracted from Herpes simplex virus (HSV) and Borrelia burgdorferi with two sets of primers that amplified a 92 bp sequence unique to HSV DNA polymerase gene and a 156 bp sequence unique to B. burgdorferi Osp-A gene (35 cycles). Following the amplification, PCR products were treated with 0-500 mM hydroxylamine hydrochloride and incubated at room temperature for 30 min. One microlitre of each hydroxylamine treated PCR product was reamplified for an additional 35 cycles. Pre- and post-hydroxylamine treated PCR products were separated by electrophoresis in 3% agarose gel. Hydroxylamine, at a concentration of 250 mM or higher, was found to effectively modify PCR products and prevent their amplification in subsequent PCR.

Artifacts↗
PubMed1992

A prospective study of the polymerase chain reaction for detection of herpes simplex virus in cerebrospinal fluid submitted to the clinical virology laboratory.

Polymerase chain reaction (PCR) was prospectively performed with cerebrospinal fluid (CSF) from 51 patients whose CSF was available for analysis and was submitted for viral culture and/or herpes simplex virus (HSV) serology and 20 patients whose CSF was submitted exclusively to the Clinical Biochemistry Laboratory. Primers were used that flanked a 92 bp segment of the HSV DNA polymerase gene (35 cycles). Amplified products were electrophoresed on agarose gel, blotted onto nylon membrane, and probed with a 32P-labelled sequence internal to the primers. For nested PCR, 1 microliter of PCR product was amplified for an additional 35 cycles before electrophoresis and Southern blot analysis. Review of the clinical records revealed that 15 patients had central nervous system (CNS) infections. Specific HSV DNA sequences were detected in CSF specimens of three of the individuals [PCR(2), nested PCR(1)]. Two of these patients had disseminated HSV infection including encephalitis and one patient had aseptic meningitis. The diagnoses of the 12 patients with CNS infection who did not have HSV DNA detected in CSF included encephalitis [varicella-zoster virus (1), cytomegalovirus (1), Mycoplasma pneumoniae (1)], meningitis [Neisseria meningitidis (1), Coccidioides immitis (1), Enterovirus (1), aseptic meningitis (1)], varicella-zoster radiculitis (2), human immunodeficiency virus dementia (2), and transverse myelitis due to Epstein-Barr virus (1). Importantly, HSV DNA was also not detected in the CSF of the 36 patients who did not have CNS infection and 20 samples submitted exclusively to the Clinical Biochemistry Laboratory. Our findings demonstrate the utility of PCR as a rapid, non-invasive method for the routine laboratory diagnosis of CNS infection due to HSV.

Adult↗
PubMed1992

Role of type 1 and type 3 fimbriae on the adherence and pathogenesis of Salmonella enteritidis in mice.

Through hemagglutination tests two isogenic strains of Salmonella enteritidis were shown to possess type 1 fimbriae (strain V) and type 1 and type 3 fimbriae (strain A). The two strains bound to human buccal and mouse small intestine epithelial cells. Strain A attached to the epithelial cells more readily and in larger numbers in comparison to strain V. Adherence of both strains were sensitive to the presence of D-mannose and pretreatment of the epithelial cells with tannic acid did not promote D-mannose resistant type binding of strain A S. enteritidis to human buccal and mouse small intestine epithelial cells. Furthermore, results from LD50 study indicated that, when the tests were carried out through oral inoculation of the mice the highly fimbriated stain A appeared to be more virulent. However, when the tests were carried out through intraperitoneal inoculation strain V was more virulent. These results indicate that adherence is a major contributing factor to the virulence of S. enteritidis and both type 1 and type 3 fimbriae contribute to this phenomenon.

Administration, Oral↗
PubMed1992

Detection of HSV-specific DNA in biopsy tissue of patients with erythema multiforme by polymerase chain reaction.

Formalin-fixed paraffin-embedded skin biopsies of lesions of erythema multiforme (EM) from 32 patients and 13 controls were examined for the presence of herpes simplex virus (HSV) by polymerase chain reaction (PCR) and for histological findings by direct immunofluorescence and staining with haematoxylin and eosin. HSV-specific DNA was detected in 23 (72%) patients. A history of recurrent skin rash was present in 59% of the PCR-positive cases, while 55% had had suspected HSV infections. Only two PCR-positive specimens were found in patients without a history of recurrent rash and/or previous oral lesions. One biopsy was positive for HSV by conventional cell cultures. There was no significant difference in histology between HSV-related and HSV-negative cases of EM. In the 13 control specimens [bullous pemphigoid (3), dermatitis herpetiformis (2), lichen planus (1), aphthous ulcer (1), fixed-drug eruption (1), varicella-zoster (1), hypereosinophilic syndrome (1), photocontact dermatitis (1), contact dermatitis (1), and cellulitis (1)], no HSV-DNA was detected.

Adult↗
PubMed1991

Anticryptococcal activity of amphotericin B-stimulated macrophages.

Amphotericin B (AmB) and its methyl ester derivative (AME) are immunoadjuvants with macrophage stimulating properties. Cultures containing AmB and murine peritoneal macrophages showed synergistic anticryptococcal activity. The antifungal activity was associated with AmB-stimulated macrophages and with their culture supernatants. Photoinactivation of the residual AmB in the macrophage culture supernatant did not result in the loss of antifungal activity. AmB-stimulated macrophage culture supernatants inhibited the growth of C. neoformans in a dose responsive manner and the activity was destroyed by incubation at 100 degrees C but not at 60 degrees C.

Amphotericin B↗
PubMed1990

Adherence and pathogenesis of Salmonella enteritidis in mice.

Adherence of many pathogenic organisms to the host cells has been associated with the presence of fimbriae. The exact role of these organelles in the adherence and pathogenesis of Salmonella enteritidis is not well established. Utilizing hemagglutination tests, S. enteritidis was shown to possess type 1 and type 3 fimbriae. Polyacrylamide gel electrophoresis of the isolated fimbriae showed that type 1 and 3 fimbriae of S. enteritidis had subunit M.r of 17 and 22 kDa, respectively. In vitro adherence assays suggested that S. enteritidis utilized type 1 fimbriae to adhere to human buccal and mouse small intestine epithelial cells. In addition, antibody produced against type 1 and type 3 fimbriae protected the mice from infection with a lethal dose of S. enteritidis. These results suggest that type 1 and possibly type 3 fimbriae are involved in the adherence and pathogenesis of S. enteritidis. The data further suggest that they may have a role in the adherence and pathogenesis of the other enteric organisms.

Animals↗