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Biomedical subjects

K L Streetz

Publications and source records attributed to K L Streetz.

4 recordsLinked to original sources

Type testing the Model 6600 plus automatic TLD reader.

The Harshaw Model 6600 Plus is a reader with a capacity for 200 TLD cards or 800 extremity cards. The new unit integrates more functionality, and significantly automates the QC and calibration process compared to the Model 6600. The Model 6600 Plus was tested against the IEC 61066 (1991-2012) procedures using Harshaw TLD-700H and TLD-600H, LiF:Mg,Cu,P based TLD Cards. An overview of the type testing procedures is presented. These include batch homogeneity, detection threshold, reproducibility, linearity, self-irradiation, residue, light effects on dosemeter, light leakage to reader, voltage and frequency, dropping and reader stability. The new TLD reader was found to meet all the IEC criteria by large margins and appears well suited for whole body, extremity and environmental dosimetry applications, with a high degree of dosimetric performance.

Equipment Design↗

Acute CMV-colitis in a patient with a history of ulcerative colitis.

A symptomatic cytomegalovirus (CMV) infection usually occurs in patients with debilitating diseases, immunosuppression, transplantations and acquired immunodeficiency syndrome (AIDS). Gastrointestinal infections with CMV, especially colitis, are usually found in immunocompromised patients and rarely affect immunocompetent subjects. Here we report the case of a young female patient with a history of ulcerative colitis (UC) who presented with an acute attack of colitis caused by CMV infection. This was documented by the presence of CMV early antigen, antibodies and evidence of CMV in the colonic mucosa. After combined anti-inflammatory and antiviral treatment the patient recovered completely. As most attention is given to CMV-pathogeneity in immunocompromised patients, here we discuss the relationship to inflammatory bowel diseases.

Acute Disease↗

Mediators of inflammation and acute phase response in the liver.

The acute phase response is a generalized response of the organism to multiple disturbances of its physiological homeostasis. It consists of local and systemic reactions. Inflammatory processes are the main causes for the initiation of these defence mechanisms. Responsible mediators for the acute phase response are predominantly cytokines, whereby the liver is the predominant target organ. Changes in hepatocyte gene expression profiles result in dramatic changes in serum concentrations of specific plasma proteins, called acute phase proteins. IL-6 was identified as the principal mediator of this reaction. Via its cellular signal transducer gp130 IL-6 induces DNA-binding of STAT transcription factors on regulatory elements of target genes. While IL-6 dependent processes are mainly conferred to be protective other inflammatory cytokines are attributed to be cytotoxic for the liver. TNF-alpha was shown to be involved in several models of liver failure as a mediator for both cytotoxicity and cell proliferation. TNF-alpha leads via caspases to the onset of apoptosis, the so-called programmed cell death. On the other hand it activates NF-kappaB thereby triggering inflammatory processes. In this review we display the relevance for intracellular actions of both cytokines in several models of liver injury. Especially we refer to the T-cell mediated Concanavalin A induced liver failure and to liver regeneration induced by CCL4 and partial hepatectomy. Both cytokines contribute in concert to a cellular balance during these pathophysiological conditions.

Acute-Phase Reaction↗