PubMed Health⌕ Search

Biomedical subjects

H Richardson

Publications and source records attributed to H Richardson.

108 records · Page 6Linked to original sources
PubMed1975

Isolation and characterization of an aetiological agent in Whipple's disease.

A cell wall deficient form of an alpha-haemolytic streptococcus was grown from a prolonged monolayer cell culture of a lymph node taken from a patient with Whipple's disease. Serological cross reactivity was shown between the organism and the material within Whipple's disease macrophages positive for diastase-resistant periodic acid-Schiff (D./P.A.S.). In vitro studies characterized the organism as a facultative intracellular parasite which caused the accumulation within cells of D./P.A.S.-positive material. These results suggest that a pathogenic bacterium is the essential aetiological agent and that the culture of Whipple's disease tissues in hypertonic media may have practical value.

Adult↗
PubMed1975

Clinical aspects of atypical mycobacterial infection.

SUMMARY: Atypical mycobacterial infections may give rise to various clinical difficulties. Case reports of six patients--three adult patients with pulmonary lesions, two children with cervical lymphadentis and one patient in whom the atypical mycobacterium appeared to be present as a commensal--illustrate these difficulties. Determination of the significance of the organism and differentiation of condition from tuberculosis and others requires consideration of the clinical picture, the results of skin testing, histologic features and cultural characteristics. Three patients, including the two children, were treated with a combination of surgery and chemotherapy, with satisfactory results. An elderly patient with chronic bronchitis and a pulmonary infection due to M. kansasii was treated successfully with antiuberculosis agents alone. Chemotherapy is being tried on a fifth patient with cavitary disease due to M. intracellulare, but is seems likely that an operation will also be required.

Adult↗
PubMed1968

Agar diffusion method for the assay of colicins.

An agar diffusion method for the assay of colicins A, B, D, E(2), E(3), and K is described. The assays were performed in large, square pyrex dishes that contained an agar layer seeded with an indicator organism sensitive to the colicin. The samples were applied to the agar in steatite beads positioned in a randomized sequence. The plates were stored at 4 C for 24 hr to allow the colicins to diffuse into the agar. After incubation at 37 C, the activity of each colicin preparation was estimated by measuring the diameter of the zone of inhibition of the growth of the indicator strain around each bead. The results of each assay were subjected to a statistical analysis, which included an analysis of variance and calculation of the theoretical regression and the confidence interval of the assay. The size of the inhibition zones, the form of the regression, and the slope of the regression of the responses were affected by the type and concentration of the agar, the depth of the agar layer, the indicator organism, the indicator inoculum density, and the time allowed for prediffusion of the colicins. Optimal conditions for the assay of each colicin were determined. Using a four-point assay design, the relative colicin concentration of unknown preparations was estimated in terms of a standard preparation of the same colicin. The experimental error of these assays (95% confidence interval) was about +/- 10%.

Agar↗
PubMedDate not supplied

Detection of Chlamydia trachomatis in genitourinary tract specimens using an automated enzyme-linked fluorescent immunoassay.

BACKGROUND AND GOAL: The VIDAS Enzyme Linked Fluorescent Assay is a fully automated assay for the detection of Chlamydia trachomatis in clinical specimens. Because there is an increasing demand for automated assays for large volume laboratories and there is little performance data available, the authors evaluated the performance of the VIDAS enzyme linked fluorescent assay by comparing it with Chlamydiazyme and polymerase chain reaction. STUDY DESIGN: Endocervical swabs from 330 women attending a hospital based obstetrics/gynecology clinic and 100 first void urine specimens from males attending a sexually transmitted disease clinic were tested by enzyme linked fluorescent assay, Chlamydiazyme, and polymerase chain reaction. RESULTS: Fourteen of 330 endocervical specimens and 14 of 100 first void urine specimens were positive by Chlamydiazyme. Enzyme linked fluorescent assay detected 12 of 14 endocervical and 11 of 14 first void urine specimens. Compared with Chlamydiazyme, enzyme linked fluorescent assay had a sensitivity of 85.7% (12 of 14) for endocervical swabs and 76.9% (11 of 14) for first void urine specimens. Polymerase chain reaction detected an additional five endocervical and two first void urine specimens that had negative results by both enzyme linked fluorescent assay and Chlamydiazyme. All 7 were confirmed positive by polymerase chain reaction using a second primer set. Using an expanded gold standard of blocked Chlamydiazyme and confirmed polymerase chain reaction, enzyme linked fluorescent assay had a sensitivity of 63.2% (12 of 19) for endocervical swabs and 68.8% (11 of 16) for first void urine specimens compared with 73.7% (14 of 19) and 87.5% (14 of 16) for Chlamydiazyme. Polymerase chain reaction had a sensitivity of 100% (19 of 19) and 93.8% (15 of 16) for endocervical swabs and first void urine specimens, respectively. The specificity of enzyme linked fluorescent assay and Chlamydiazyme was 100%. CONCLUSIONS: The VIDAS enzyme linked fluorescent assay for the detection of Chlamydia trachomatis in genitourinary specimens is highly specific but is not sufficiently sensitive for use as a routine diagnostic test.

Automation↗
PubMedDate not supplied

Cutting the children.

Explore the source record for details and available documents.

Aid to Families with Dependent Children↗