Optimization of properties of carburized high-chromium steels

The influence of the pack carburization regime on the bulk strength and wear properties of hypoeutectoid (0.3 wt% C, 3–17wt% Cr) and hypereutectoid (0.8 wt% C, 4–16 wt% Cr) high-chromium steels was examined (950–1050 °C, and duration, 4–8h). The results obtained enable an optimum combination of bulk (tensile, bending and impact strength) and surface properties (abrasive and unlubricated sliding wear resistance) of a carburized high-chromium steel to be obtained.     

Serologic survey of Toxoplasma gondii in grizzly bears (Ursus arctos) and black bears (Ursus americanus), from Alaska, 1988 to 1991

We tested 644 serum samples from 480 grizzly bears and 40 black bears from Alaska (USA), collected between 1988 and 1991, for Toxoplasma gondii antibodies, using a commercially available latex agglutination test (LAT). A titer > or = 64 was considered positive. Serum antibody prevalence for T. gondii in grizzly bears (Ursus arctos) was 18% (87 of 480). Prevalence ranged from 9% (seven of 77) on Kodiak Island to 28% (15 of 54) in northern Alaska. Prevalence was directly correlated to age. No grizzly bears < 2-year-old had T. gondii antibody. High antibody titers were found mainly in grizzly bears captured north of the Arctic Circle. Antibody prevalence in black bears (Ursus americanus) from Interior Alaska was 15% (six of 40), similar to the prevalence in grizzly bears from the same area (13%; five of 40).     

Population dynamics of the deer mouse (Peromyscus maniculatus) and Sin Nombre virus, California Channel Islands

Alteration of the wild-type (wt) p53 gene by mutation, deletion or re-arrangement is a major factor in the development of human colon cancer. Recent studies have demonstrated that p53 might be an essential component of the apoptotic pathway triggered by DNA-damaging stimuli such as chemotherapeutic agents and ionizing radiation. We examined the anti-tumor effects of adenovirus-mediated wt-p53 gene transfer in combination with a chemotherapeutic drug on the human colon cancer cell line WiDr, which is homozygous for a mutation in the p53 gene. Treatment with the chemotherapeutic drug cisplatin following infection with a replication-deficient, recombinant adenoviral vector expressing wt-p53 (termed AdCMVp53) significantly suppressed the growth of WiDr cells compared to single treatments alone. To evaluate the in vivo efficacy of AdCMVp53 and cisplatin given sequentially, WiDr cells were inoculated s.c. in nu/nu mice. After 3 days, AdCMVp53 was injected s.c. into the area where tumor cells were implanted, followed by i.p. administration of cisplatin. Analysis of initial growth inhibition at 21 days demonstrated a profound therapeutic cooperativity, though administration of either AdCMVp53 or cisplatin alone was followed only by a slowing of growth. Our results suggest that gene therapy using wt-p53-expressing adenovirus in combination with a chemotherapeutic DNA-damaging drug could be a useful strategy for treating human colon cancer.     

TR1, a new member of the tumor necrosis factor receptor superfamily, induces fibroblast proliferation and inhibits osteoclastogenesis and bone resorption

A newly identified member of the tumor necrosis factor receptor (TNFR) superfamily shows activities associated with osteoclastogenesis inhibition and fibroblast proliferation. This new member, called TR1, was identified from a search of an expressed sequence tag database, and encodes 401 amino acids with a 21-residue signal sequence. Unlike other members of TNFR, TR1 does not contain a transmembrane domain and is secreted as a 62 kDa glycoprotein. TR1 gene maps to chromosome 8q23-24.1 and its mRNA is abundantly expressed on primary osteoblasts, osteogenic sarcoma cell lines, and primary fibroblasts. The receptors for TR1 were detected on a monocytic cell line (THP-1) and in human fibroblasts. Scatchard analyses indicated two classes of high and medium-high affinity receptors with a kD of approximately 45 and 320 pM, respectively. Recombinant TR1 induced proliferation of human foreskin fibroblasts and potentiated TNF-induced proliferation in these cells. In a coculture system of osteoblasts and bone marrow cells, recombinant TR1 completely inhibited the differentiation of osteoclast-like multinucleated cell formation in the presence of several bone-resorbing factors. TR1 also strongly inhibited bone-resorbing function on dentine slices by mature osteoclasts and decreased 45Ca release in fetal long-bone organ cultures. Anti-TR1 monoclonal antibody promoted the formation of osteoclasts in mouse marrow culture assays. These results indicate that TR1 has broad biological activities in fibroblast growth and in osteoclast differentiation and its functions.     

Practice guideline for forensic pathology. Members of the Forensic Pathology Committee, College of American Pathologists

The guideline for forensic pathology was prepared by the Forensic Pathology Committee of the College of American Pathologists. The definitional criteria for forensic pathology included in this guideline have been approved both by the House of Delegates and the Board of Governors of the College of American Pathologists. The guideline presents an overview of forensic pathology and an approach to the forensic autopsy and medicolegal death investigation. Emphasis is placed on the role of forensic pathology in maintaining public health, welfare, and safety. The guideline is intended to serve as an educational tool, and its use should be determined by the individual circumstances and settings of specific cases.