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P D Mitchell

Publications and source records attributed to P D Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed1995

Ixodes dammini as a potential vector of human granulocytic ehrlichiosis.

Little is known about the epidemiology and mode of transmission of the agent of human granulocytic ehrlichiosis (HGE). Analyses of an engorged female Ixodes dammini tick removed from an HGE patient and 101 field-collected I. dammini and Dermacentor variabilis from three Wisconsin counties for Borrelia burgdorferi and Ehrlichia phagocytophila/Ehrlichia equi DNA revealed that the patient tick and 7 of 68 I. dammini ticks from Washburn County collected in 1982 and 1991 were positive for ehrlichial DNA; 10 ticks from the same collections were positive for B. burgdorferi. Two specimens (2.2%) were positive for both organisms. Serologic evidence for exposure to the agent of HGE or its relatives was detected in 3 of 25 Lyme disease patients from the upper Midwest. These data argue that I. dammini is a common vector for transmission of both Lyme disease and HGE.

Animals↗
PubMed1994

An evaluation of media for transport of tissues infected with Borrelia burgdorferi.

Currently, the best medium for culture of Borrelia burgdorferi, the etiologic agent of Lyme disease, is Barbour-Stoenner-Kelly (BSK), or its modifications. This medium is complex, expensive, and laborious to prepare. A recent report suggested that a less expensive and simpler medium, hypertonic Columbia broth, might be useful as a transport medium for human tissues infected with B burgdorferi. To test this observation, hypertonic Columbia broth, Amies broth, distilled water, physiologic saline, phosphate-buffered saline (PBS), and modified Stuart medium were compared with BSK II as transport media, using ear and tail tissue samples from B burgdorferi-infected laboratory mice and using holding times and temperatures simulating actual transport conditions. The results showed BSK II to be markedly superior to the other media tested, although B burgdorferi remained viable in a few tissue samples held at room temperature in hypertonic Columbia broth, physiologic saline, or PBS for up to 2 days. Barbour-Stoenner-Kelly II continues to be the best medium for transport of tissues infected with B burgdorferi.

Animals↗
PubMed1994

Target imbalance: disparity of Borrelia burgdorferi genetic material in synovial fluid from Lyme arthritis patients.

Lyme arthritis is a late manifestation of Lyme disease that results in episodic synovial inflammation and swelling. Although this process is thought to be driven directly by the spirochetal etiologic agent, Borrelia burgdorferi, the organism itself has been recovered by culture only twice. In contrast, polymerase chain reaction (PCR) studies are usually positive. This apparent discrepancy in 19 culture-negative synovial fluid specimens from 18 patients with Lyme arthritis was investigated. In all 19, DNA sequences characteristic of plasmid-encoded genes OspA and OspB were easily detected. However, despite equivalent or even superior analytic sensitivity for detection of cultured organisms, the reactivity of two genomic DNA targets was often weak or absent altogether in the clinical specimens. This apparent overrepresentation of B. burgdorferi plasmid sequences was found exclusively in clinical specimens and not in cultured organisms. The physiologic imbalance of genomic and plasmid DNA reactivity in B. burgdorferi infection may signal an underlying pathogenetic mechanism.

Antigens, Bacterial↗
PubMed1994

Comparison of four immunoserologic assays for detection of antibodies to Borrelia burgdorferi in patients with culture-positive erythema migrans.

In view of the significant sequelae associated with Lyme borreliosis, there is a need for timely and accurate diagnosis of erythema migrans (EM). Although Borrelia burgdorferi can be cultured from biopsies of EM lesions, immunodiagnostic testing is more widely available. Four immunoserologic methods were studied by using the sera of 51 patients with EM lesions that were culture positive for B. burgdorferi. Nineteen patients had single primary lesions, and thirty-two had multiple secondary lesions. At the time of biopsy, 40 patients, 8 with primary lesions and all patients with secondary lesions, were seropositive by an immunoglobulin M (IgM) indirect fluorescent-antibody (IgM IFA) test (Bion Enterprises). Twenty-three patients were seropositive by a whole-cell fluorescence enzyme immunoassay (EIA) (BioWhittaker, Inc.), twenty-two were positive by immunoblotting (ViroStat, Inc.), and one was positive by a P39 recombinant EIA (P39 EIA) (General Biometrics, Inc.). Sera from various patient control groups were tested: rheumatoid arthritis (n = 19), infectious mononucleosis (n = 20), systemic lupus (n = 22), syphilis (n = 13), streptococcal sequelae (n = 20), and healthy subjects (n = 16). None of these sera reacted with the IgM IFA test or P39 EIA. Fifteen reacted with the fluorescence EIA. We conclude that the IgM IFA test is an effective and reliable assay for the diagnosis of EM, particularly for patients with secondary lesions. Immunoblot, fluorescence EIA, and P39 EIA lack the sensitivity to reliably diagnose EM.

Adolescent↗
PubMed1993

Evaluation of a commercial DNA purification system for plasmid analysis of nosocomial bacterial pathogens.

This study evaluated the Promega Magic Minipreps (MM) (Promega Corporation, Madison, WI) DNA purification system for use in plasmid analysis of common nosocomial bacterial pathogens. The MM system is a kit that includes lysis solutions and buffers and incorporates a minicolumn of DNA binding resin for recovery of plasmid DNA. The MM system was used according to the manufacturer's directions to recover plasmids for agarose gel electrophoresis from clinical isolates of Acinetobacter calcoaceticus, Enterobacter cloacae, and Klebsiella pneumoniae. For Salmonella enteritidis and Staphylococcus aureus, lysozyme and lysostaphin, respectively, were used for pretreatment. Plasmid DNA from ten isolates could be recovered in approximately one hour with very little manipulation and no phenol/chloroform extractions and was suitable for restriction endonuclease digestion. Compared with a standard miniprep protocol, the MM system was much easier to perform and resulted in significant cost savings due to a 50% reduction in technologist time. The authors conclude that the MM system is a convenient and cost-effective method for clinical microbiology laboratories for recovering plasmid DNA from nosocomial bacterial pathogens.

Acinetobacter calcoaceticus↗
PubMed1993

Isolation of Borrelia burgdorferi from skin biopsy specimens of patients with erythema migrans.

Procedures for the cultural isolation and identification of Borrelia burgdorferi from skin biopsy specimens are described. B. burgdorferi was isolated from 24 of 34 skin biopsy specimens from patients with erythema migrans. Eight of the culture-positive patients had single, primary lesions and 16 had multiple, secondary lesions. The 17 male and 7 female patients were 2 to 70 years old. Biopsy samples were obtained from erythematous or normal-appearing skin within 1 cm of the peripheral aspect of the lesion. Twenty-three of the isolates were detected within 8 days of incubation in Barbour-Stoenner-Kelly medium with no antimicrobial agents. The identities of the isolates were determined by reactivity with monoclonal antibodies H9724 and H5332. Cultivation of B. burgdorferi from skin lesions suggestive of erythema migrans is a practical and clinically relevant procedure. Clinical isolates and corresponding patient sera and urine will contribute to efforts to improve existing immunoserologic testing methods and develop new assays to diagnose Lyme borreliosis.

Adult↗
PubMed1993

Streptococcus bovis does not selectively colonize colorectal cancer and polyps.

The objective was to determine if Streptococcus bovis selectively colonizes colorectal cancer and polyps. Stools were submitted before colonoscopy; fluid and selected tissue biopsies obtained during colonoscopy were cultured for S. bovis. The setting was a large multispecialty clinic. Outpatients undergoing colonoscopy for suspected colorectal cancer and polyps were the participants. Forty studies on 35 patients were performed. One of 35 stools (2.9%) obtained before colonoscopy yielded S. bovis. S. bovis was cultured from three of 40 fluid aspirations (7.5%), one of 33 adenomas biopsied (3%), none of six adenocarcinomas, none of 14 nonneoplastic polyps, one of 40 (2.5%) biopsies from normal mucosa adjacent to an adenoma, and none of 40 mucosal biopsies remote from any lesion. These data do not support selective colonization of colorectal neoplasms by S. bovis.

Adenocarcinoma↗
PubMed1993

Primary and secondary erythema migrans in central Wisconsin.

BACKGROUND AND DESIGN: We report a series of 28 consecutive patients with erythema migrans (EM) who underwent skin biopsies for culture of Borrelia burgdorferi. Culture results, Lyme serologic findings, and clinical features in patients with only primary EM are compared with those in patients with secondary EM. RESULTS: Culture preparations of skin specimens obtained from six of 12 patients with only primary EM, and from 14 of 16 patients with secondary EM were positive for B burgdorferi. Seven patients with only primary EM were initially seronegative, and only one patient had an annular lesion. A central crusted punctum was present in five of six primary EM lesions that were not culture positive, but in none of nine culture-positive primary EM lesions. Patients with secondary EM were all seropositive and had less cutaneous and more constitutional symptoms than patients with only primary EM. Three patients with secondary EM had abnormal liver enzyme profiles, one patient had complete heart block, and one patient had myocarditis simulating infarction. Less than one third of all patients recalled a tick bite. An isomorphic nonresponse was seen in skin previously involved with secondary EM in one patient who had a drug exanthem from amoxicillin. CONCLUSIONS: Borrelia burgdorferi can be reliably cultured from skin biopsy specimens of secondary EM. Culture preparation aids definitive diagnosis of Lyme disease in patients with only primary EM who often lack constitutional symptoms, have nondiagnostic lesions, or are seronegative.

Administration, Oral↗
PubMed1991

Diagnostic dilemma for the 1990s: Lyme disease versus rheumatic fever.

A 15-year-old boy developed an annular erythematous skin rash, fever, knee pain, syncope, and was found to be in complete heart block requiring temporary transvenous pacing. His recovery was complete following therapy with high dose steroids, aspirin, and IV ceftriaxone followed by oral penicillin. Serologic tests documented diagnostic levels of antibodies to Borrelia burgdorferi as well as to Group A streptococcal DNase B. Diagnoses of both Lyme disease and rheumatic fever are based on clinical presentation and serologic confirmation. Our patient had a clinical presentation compatible with either diagnosis and serologic test results suggestive of infection by both B burgdorferi and Group A streptococci. The patient's management was aimed at preventing complications of both diseases, since clinicians involved with the patient's case could not agree on the most likely diagnosis. We present this case to emphasize the following: both rheumatic fever and Lyme disease should be considered in patients presenting with annular skin rashes and complete heart block; serologic studies may be confusing in both Lyme disease and rheumatic fever since neither is entirely sensitive nor specific and efforts should be made to document the causative organism by appropriate cultures, biopsies, and stains when possible; and improved immunoserologic testing for Lyme disease, in particular, is highly needed.

Adolescent↗
PubMed1990

FPL 62064, a topically active 5-lipoxygenase/cyclooxygenase inhibitor.

FLP 62064 [N-(4-methoxyphenyl)-1-phenyl-1H-pyrazole-3-amine] is a dual inhibitor of prostaglandin synthetase and 5-lipoxygenase. The compound had anti-inflammatory activity in vivo in a number of models. It inhibited peritoneal inflammation induced by immune-complex when given locally. When applied to the skin, FPL 62064 inhibited UV irradiation-induced erythema and PGE2 formation in the guinea pig and also oedema formation and eicosanoid production in the mouse ear produced by arachidonic acid. Co-injected with arachidonic acid in rabbit skin, FPL 62064 inhibited oedema and eicosanoid formation.

Administration, Cutaneous↗
PubMed1990

FPL 63012AR: a potent D1-receptor agonist.

1. FPL 63012AR is a D1-receptor agonist in the dog kidney, 10 times as potent as dopamine, reducing renal vascular resistance by 20% with an intra-arterial dose of 0.42 nmol kg-1. 2. No prejunctional inhibitory D2-receptor agonist activity was detected in either the isolated ear artery of the rabbit or in the conscious dog as D2-receptor-mediated emesis. 3. Unlike dopamine, FPL 63012AR had no significant agonist activity at alpha 1-, alpha 2-, beta 1- or beta 2-adrenoceptors. 4. FPL 63012AR is a potent inhibitor of [3H]-noradrenaline uptake (Uptake1) into brain synaptosomes, with an IC50 of 29.5 nM, i.e. 9.2 times more potent than dopamine. 5. The ability to block Uptake1, in the anaesthetised dog was confirmed by inhibition of the tyramine-induced pressor and inotropic responses. 6. Intravenous infusion of FPL 63012AR in anaesthetized and conscious dogs (0.3 to 3 nmol kg-1 min-1) reduced vascular resistance and increased blood flow to the kidney which was accompanied by hypotension and tachycardia. 7. It is concluded that FPL 63012AR is an example of a novel class of potent agonists at the D-receptor. Such compounds may have the potential for use clinically in improving renal perfusion and reducing afterload.

Anesthesia↗
PubMed1988

Sensitivity and specificity of clinical case definitions for pertussis.

We evaluated the diagnostic performance of 15 clinical case definitions for pertussis in 233 patients who developed acute respiratory illness during community outbreaks in Wisconsin and Delaware. Using results from culture (Regan-Lowe media) and serology (Ig-class-specific ELISA) as diagnostic standards, cough for greater than or equal to 14 days was both sensitive (84 per cent-92 per cent) and specific (63 percent-90 per cent) in identifying patients with pertussis. This definition may be useful in monitoring pertussis outbreaks and for investigating contacts of culture-positive cases.

Adolescent↗
PubMed1987

Inhibition of Uptake1 by dopexamine hydrochloride in vitro.

1 Dopexamine hydrochloride, a compound under evaluation for the acute treatment of heart failure, was examined in vitro for its ability to prevent neuronal uptake of noradrenaline. 2 Despite possessing only weak beta 1-adrenoceptor agonist activity in paced guinea-pig left atria, dopexamine hydrochloride was only 23 times less potent than isoprenaline in augmenting responses of field-stimulated atrial preparations. 3 This potent effect was not observed in field-stimulated atria depleted of noradrenaline by reserpine and in the presence of cocaine was greatly reduced (1 microM) or abolished (50 microM). 4 Dopexamine hydrochloride (3 microM) potentiated the inotropic effect of exogenous noradrenaline in paced atria, thereby resembling cocaine (10 microM) and dopamine (30 microM), both of which are known inhibitors of Uptake. 5 The sodium-dependent uptake of [3H]-noradrenaline into rabbit brain synaptosomes was prevented by dopexamine hydrochloride (IC50 26 nM) and cocaine (IC50 108 nM), as well as by two other catecholamines used in the treatment of heart failure, dopamine (IC50 270 nM) and dobutamine (IC50 380 nM). 6 The cardiac stimulant effect of dopexamine hydrochloride reported in dogs and in patients with heart failure, may therefore be due in part to potentiation of endogenous catecholamines.

Adrenergic Agonists↗
PubMed1981

Does bacteremia follow upper gastrointestinal endoscopy?

To determine the risk of bacteremia, 53 patients had blood collected for culture before and five, ten and 15 minutes following fiberoptic endoscopy of the upper digestive tract. One patient had transient bacteremia with Acinetobacter Sp. five minutes after endoscopy. Combining our study with four others, 447 patients have been evaluated of which 6% had bacteremia after upper gastrointestinal endoscopy. Biopsy or other endoscopic operation does not increase the likelihood of bacteremia. We recommend careful attention to instrument and accessory cleaning and prophylactic antibiotics (probably penicillin or oxacillin alone suffices) only for patients with prosthetic heart valves.

Acinetobacter Infections↗