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Biomedical subjects

J Nowakowski

Publications and source records attributed to J Nowakowski.

At least 19 recordsLinked to original sources
PubMed2001

Laboratory diagnostic techniques for patients with early Lyme disease associated with erythema migrans: a comparison of different techniques.

Recently, a number of refinements in diagnostic modalities for detection of Borrelia burgdorferi infection have been developed. These include large-volume blood cultures, quantitative polymerase chain reaction (PCR) techniques, and 2-stage serologic testing. In the present study, we compared 6 diagnostic modalities in 47 adult patients who had a clinical diagnosis of erythema migrans. Quantitative PCR on skin biopsy-derived material was the most sensitive diagnostic method (80.9%), followed by 2-stage serologic testing of convalescent-phase samples (66.0%), conventional nested PCR (63.8%), skin culture (51.1%), blood culture (44.7%), and serologic testing of acute-phase samples (40.4%). Results of all assays were negative for 3 patients (6.4%). We conclude that the clinical diagnosis of erythema migrans is highly accurate in an area where B. burgdorferi is endemic if it is made by experienced health care personnel, but some patients with this diagnosis may not have B. burgdorferi infection. No single diagnostic modality is suitable for detection of B. burgdorferi in every patient with erythema migrans.

Biopsy↗
PubMed2001

Yield of large-volume blood cultures in patients with early Lyme disease.

To improve yield, 6 3-mL plasma cultures (18 mL total) were established for adult patients with early Lyme disease associated with erythema migrans. Borrelia burgdorferi was recovered from the blood of 22 (44.0%) of 50 evaluable patients. The recovery rate per plasma culture and the frequency of positive results for plasma cultures for individual patients were consistent with a level of spirochetemia of approximately 0.1 cultivable cell/mL of whole blood. Our findings suggest that, if further improvements in the yield of blood cultures are possible, they probably will depend on enhancing the sensitivity of the culture method rather than increasing the volume of material cultured.

Bacteremia↗
PubMed2001

Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite.

BACKGROUND: It is unclear whether antimicrobial treatment after an Ixodes scapularis tick bite will prevent Lyme disease. METHODS: In an area of New York where Lyme disease is hyperendemic we conducted a randomized, double-blind, placebo-controlled trial of treatment with a single 200-mg dose of doxycycline in 482 subjects who had removed attached I. scapularis ticks from their bodies within the previous 72 hours. At base line, three weeks, and six weeks, subjects were interviewed and examined, and serum antibody tests were performed, along with blood cultures for Borrelia burgdorferi. Entomologists confirmed the species of the ticks and classified them according to sex, stage, and degree of engorgement. RESULTS: Erythema migrans developed at the site of the tick bite in a significantly smaller proportion of the subjects in the doxycycline group than of those in the placebo group (1 of 235 subjects [0.4 percent] vs. 8 of 247 subjects [3.2 percent], P<0.04). The efficacy of treatment was 87 percent (95 percent confidence interval, 25 to 98 percent). Objective extracutaneous signs of Lyme disease did not develop in any subject, and there were no asymptomatic seroconversions. Treatment with doxycycline was associated with more frequent adverse effects (in 30.1 percent of subjects, as compared with 11.1 percent of those assigned to placebo; P<0.001), primarily nausea (15.4 percent vs. 2.6 percent) and vomiting (5.8 percent vs. 1.3 percent). Erythema migrans developed more frequently after untreated bites from nymphal ticks than after bites from adult female ticks (8 of 142 bites [5.6 percent] vs. 0 of 97 bites [0 percent], P=0.02) and particularly after bites from nymphal ticks that were at least partially engorged with blood (8 of 81 bites [9.9 percent], as compared with 0 of 59 bites from unfed, or flat, nymphal ticks [0 percent]; P=0.02). CONCLUSIONS: A single 200-mg dose of doxycycline given within 72 hours after an I. scapularis tick bite can prevent the development of Lyme disease.

Adolescent↗
PubMed2001

Asymptomatic Borrelia burgdorferi infection.

Little is known about the natural history of asymptomatic Borrelia burgdorferi infection. Our analysis of the asymptomatic infections diagnosed serologically in a recent OspA vaccine trial conducted in the United States (N Engl J Med 1998;339: 209-215), suggests that the natural history of this event is more benign than that reported for untreated patients with erythema migrans (Ann Intern Med 1987;107: 725-731). We hypothesize that this is due either to incorrect diagnosis since the specificity of the serologic criteria used to diagnose asymptomatic infection in the vaccine study is unknown, or to infection with non-pathogenic strains of B. burgdorferi. Increasing evidence indicates that the invasive potential of strains of B. burgdorferi varies according to the specific subtype. Theoretically, a serologic testing method could be devised which would distinguish infection with invasive versus non-invasive strains of B. burgdorferi, and allow testing of the second hypothesis.

Bacterial Vaccines↗
PubMed2001

Efficacy of an evernimicin (SCH27899) in vitro and in an animal model of Lyme disease.

The MICs of evernimicin at which 90% of Borrelia burgdorferi patient isolates were inhibited ranged from 0.1 to 0.5 microg/ml. Evernimicin was as effective as ceftriaxone against B. burgdorferi in a murine model of experimental Lyme disease. As assessed by culturing the urinary bladders of infected C3H mice, no live Borrelia isolates were recoverable following antibiotic treatment.

Aminoglycosides↗
PubMed2001

Characterization of Borrelia burgdorferi isolated from erythema migrans lesions: interrelationship of three molecular typing methods.

Genetic diversity among Borrelia burgdorferi isolates recovered from the skin of Lyme disease patients was assessed by ribosomal DNA (rDNA) spacer restriction fragment length polymorphism analysis, genomic restriction site polymorphism analysis, and plasmid content analysis. There was a significant association between the three rDNA spacer types, the six pulsed-field gel types, and plasmid content (P < 0.001). The association between distinct chromosomal and plasmid markers implies a clonal origin for each genotype.

Adult↗
PubMed2000

Alternative conformations of a nucleic acid four-way junction.

A crystal structure of a 108 nucleotide RNA-DNA complex containing a four-way junction was solved at 3.1 A resolution. The structure of the junction differs substantially from the "stacked-X" conformation observed previously, due to a 135 degrees rotation of the branches. Comparison of the two conformers provides insight into the factors contributing to the flexibility of four-way junctions. The stacked-X conformation maximizes base-stacking but causes unfavorable repulsion between phosphate groups, whereas the 135 degrees -rotated "crossed" conformation minimizes electrostatic clashes at the expense of reduced base-stacking. Despite the large rotation of the branches, both junction structures exhibit an antiparallel arrangement of the continuous strands and opposite polarity of the crossover strands.

Base Pairing↗
PubMed2000

Failure of treatment with cephalexin for Lyme disease.

CONTEXT: Lyme disease typically presents with a skin lesion called erythema migrans (EM), which though often distinctive in appearance may be confused with cellulitis. The first-generation cephalosporin, cephalexin monohydrate, is effective for treating bacterial cellulitis but has not been recommended or studied for treating Lyme disease because of poor in vitro activity. OBJECTIVE: To describe the outcome of patients with EM who were treated with cephalexin. PATIENTS AND METHODS: Patients presenting with EM to the Lyme Disease Diagnostic Center in Westchester, NY (May 1992-September 1997). A 2-mm punch biopsy specimen of the leading edge of the EM lesion and/or blood was cultured for Borrelia burgdorferi. RESULTS: Eleven (2.8%) of 393 study patients had been initially treated with cephalexin prior to our evaluation; 9 (82%) were originally diagnosed with cellulitis. Cephalexin was administered for 8.6 days (range, 2-21 days) prior to presentation. All 11 patients had clinical evidence of disease progression, including 8 whose rash enlarged, 2 who developed seventh-nerve palsy (1 with new EM lesions), and 1 who developed new EM lesions. Borrelia burgdorferi grew in cultures from 5 patients despite a mean of 9.8 days of treatment with cephalexin (range, 5-21 days). CONCLUSION: Cephalexin should not be used to treat early Lyme disease and should be prescribed with caution during the summer months for patients believed to have cellulitis in locations where Lyme disease is endemic.

Adult↗
PubMed2000

A limitation of 2-stage serological testing for Lyme disease: enzyme immunoassay and immunoblot assay are not independent tests.

To improve the accuracy of testing for antibody to Borrelia burgdorferi, 2-stage conditional testing has been recommended, in which sera that yield positive or equivocal results in a first-stage test (e.g., an ELISA) are then tested by immunoblot assay. The increased specificity anticipated with sequential testing, however, depends on immunoblot assays and ELISAs being independent tests. To examine whether they are independent, control serum samples were tested with 2 different commercially available IgM ELISAs and with an IgM immunoblot assay kit. The frequency of false-positive IgM immunoblot assays was significantly higher with ELISA-reactive than with ELISA-negative serum samples (P</=.001). In addition, there was a highly significant direct correlation between the number of reactive bands on IgM blotting and the rate of false-positive results by IgM ELISA (P<.0001). These observations demonstrate that IgM ELISAs and IgM immunoblot assays for antibodies to B. burgdorferi are not independent tests. Therefore, when used in sequential testing for Lyme disease, the immunoblot assay should be considered a test that supplements rather than confirms an ELISA.

Antibodies, Bacterial↗
PubMed2000

Comparison of the yields of blood cultures using serum or plasma from patients with early Lyme disease.

In an initial experiment, culture-grown Borrelia burgdorferi was added to freshly collected uninfected human blood. This in vitro study demonstrated that more spirochetes were distributed into the plasma than into the serum fraction. In a subsequent clinical study, B. burgdorferi was recovered from plasma cultures of approximately 50% of 42 patients with early Lyme disease associated with erythema migrans. The rate of recovery from plasma cultures was significantly greater than that from serum cultures (P < 0.001).

Bacteriological Techniques↗
PubMed2000

Fibrillar amyloid-beta production, accumulation, and recycling in transgenic mice pancreatic acinar cells and macrophages.

Amyloid-beta (A beta) production, accumulation, and recycling were examined by light and electron microscopy in the pancreas of transgenic mice (from 45 days to 22 months of age) that express the gene for the carboxy-terminal fragment of the human amyloid-beta protein precursor. Ultrastructural immunocytochemistry revealed four types of cells accumulating fibrillar A beta 1-40 in cytoplasmic vacuoles: acinar pancreatic cells, macrophages infiltrating stroma, epithelial cells of pancreatic ducts, and blood monocytes/macrophages in the lumen of pancreatic vessels. The ultrastructure of amyloid deposits suggests that each of these four types of cells produces fibrillar A beta. Three basic types of amyloid deposits were distinguished: primary vacuoles in different stages of amyloid aggregation and fibrillization, secondary vacuoles that are the product of fusion of primary vacuoles, and phagosome-like vacuoles with morphologically intact fibrillar amyloid and residues of ingested cells. Amyloid production in acinar pancreatic cells starts in mice younger than 45 days, progresses in 2- to 7-month-old mice, and plateaus in the second year of life. In macrophages, amyloid appears in 60-day-old mice, and the increase in the number of macrophages and the amount of amyloid in their cytoplasm correlates with age.

Aging↗
PubMed1999

Temporal relation between Ixodes scapularis abundance and risk for Lyme disease associated with erythema migrans.

Understanding the role that nymphal and female ticks, Ixodes scapularis, have in the epidemiology of Lyme disease is essential to the development of successful prevention programs. In this study, the authors sought to evaluate the seasonal and annual relations between tick densities and patients > or = 16 years of age diagnosed with erythema migrans (EM), the rash associated with early Lyme disease. Ticks were collected weekly by drag sampling throughout most of the year from 1991 to 1996 in Westchester County, New York. The number of EM cases was based on patients diagnosed at the Westchester County Medical Center using Centers for Disease Control and Prevention (CDC) criteria. No patients with EM were diagnosed from January through April, when only adult ticks were active. Correlation analysis between monthly tick densities and EM incidence was significant for nymphs (r = 0.87, p < 0.01), but not for adult ticks (r = -0.57, p > 0.05). There was a strong, although not significant, correlation between peak annual number of patients with EM and peak nymphal tick abundance (r = 0.76, p = 0.08). These data indicate that bites from adult I. scapularis only rarely result in Lyme disease, and that annual nymphal tick abundance determines exposure. This suggests that annual fluctuations in Lyme disease case numbers are largely due to natural changes in tick abundance and, therefore, that control of nymphal I. scapularis should be a major component of Lyme disease prevention efforts.

Adult↗
PubMed1999

Comparison of culture-confirmed erythema migrans caused by Borrelia burgdorferi sensu stricto in New York State and by Borrelia afzelii in Slovenia.

BACKGROUND: The clinical manifestations of Lyme borreliosis in North America and Europe seem to differ, but a systematic comparison has never been done. OBJECTIVE: To compare European and U.S. patients with culture-confirmed erythema migrans. DESIGN: Prospective, clinical cohort study. SETTING: University medical centers in Westchester County, New York, and Ljubljana, Slovenia. PATIENTS: 119 U.S. patients with Borrelia burgdorferi sensu stricto infection and 85 Slovenian patients with B. afzelii infection. MEASUREMENTS: Interview, physical examination, and laboratory assays. RESULTS: Compared with Slovenian patients, U.S. patients had erythema migrans for a briefer duration (median duration, 4 days compared with 14 days; P < 0.001) but were more likely to have systemic symptoms (P = 0.01), abnormal findings on physical examination (P < 0.001), and seroreactivity (P < 0.001). Central clearing of erythema migrans lesions was more likely in Slovenian patients (P < 0.001). CONCLUSIONS: Erythema migrans caused by B. afzelii in Slovenia and erythema migrans caused by B. burgdorferi in New York have distinct clinical presentations. Caution should be used when clinical and laboratory experience from one side of the Atlantic is applied to patients on the other.

Adolescent↗
PubMed1999

Crystal structure of an 82-nucleotide RNA-DNA complex formed by the 10-23 DNA enzyme.

The structure of a large nucleic acid complex formed by the 10-23 DNA enzyme bound to an RNA substrate was determined by X-ray diffraction at 3.0 A resolution. The 82-nucleotide complex contains two strands of DNA and two strands of RNA that form five double-helical domains. The spatial arrangement of these helices is maintained by two four-way junctions that exhibit extensive base-stacking interactions and sharp turns of the phosphodiester backbone stabilized by metal ions coordinated to nucleotides at these junctions. Although it is unlikely that the structure corresponds to the catalytically active conformation of the enzyme, it represents a novel nucleic acid fold with implications for the Holliday junction structure.

Base Sequence↗