Intrauterine transfusions influence fetal leukocyte counts and subsets

Histamine is an important mediator in allergic reactions, gastric acid secretions, and neurotransmission in the central nervous system. Basophils and mast cells are the main sources of histamine, which is formed from L-histidine by histidine decarboxylase (HDC). However, the regulatory mechanism of HDC in these cells remains unclear. We examined the regulation of HDC activity and gene expression using a unique human mast cell line, HMC-1, after stimulation with phorbol 12-myristate 13-acetate (PMA) or ionomycin. HDC activity was increased from 52.1+/-0.4 (mean+/-standard deviation) to 154+/-6.9, or 105.6+/-6.2 pmol/min/mg protein (n = 3), 4 hours after stimulation with PMA (10 ng/mL) or ionomycin (10[-6] M). Although actinomycin D had no effect on this increase, cycloheximide completely inhibited the increase caused by these stimuli. The population of HMC-1 cells containing HDC protein was increased after stimulation with either PMA or ionomycin as evaluated by immunocytochemical analysis with anti-HDC antibody as a marker. HMC-1 constitutively expressed HDC mRNA, and its level was not increased with these stimuli. These results suggest that the increase of HDC activity in HMC-1 induced by PMA or ionomycin is regulated at the translational level.     

Experimental studies of mechanically-induced articular cartilage defects following implantation of allogeneic embryonal chondrocytes in a collagen-fibrin gel in chickens

Full thickness defects (diameter 1,7 mm; depth 2,5 mm) were created mechanically in articular cartilage and subchondral bone of the condyles of tibiotarsal joints of 9-month old chickens. This full-thickness defects were repaired with cultured allogenic embryonic chick epiphyseal chondrocytes from the tibiae and femura of 10-days-old chicken embryos. The cells were embedded in a collagen-fibrinogen-matrix. Controls were similarly operated, but received either no treatment or implants the delivery substance only. Healing of the defects was observed macroscopically, histologically, histochemically and histomorphometrically after 3, 12 and 24 weeks. This graft was successfully transplanted in mechanically induced defects in 80%. The resulting hyaline cartilage was structurally reorganized according to the host pattern and under the influence of environmental conditions. The articular zone preserved it's cartilaginous phenotype, whereas the subchondral regions were transformed into bone. 12 weeks after the operation the defects in the experimental group were completely filled. In all instances in this group, there was an initial extreme increase of mitotic rate and cell number. After 24 weeks normal and subnormal values were founded. The defects in the control groups healed with fibrocartilage. Our results showed, that only the defects in the experimental group were completely filled with reparative hyaline cartilage tissue. In the present study the mixture of cultured allogenic embryonic chondrocytes and a collagen-fibrinogen-matrix was used successfully as a transplant for repairing defects in articular cartilage of chickens. Thus allogenic transplantation of cultured embryonal chondrocytes appears to be one of the most promising methods for the restoration of articular cartilage.     

HIV arthritis

Whether reexposure of varicella-immune persons to varicella-zoster virus would protect against or predispose to development of zoster was analyzed. The rate of zoster in 511 leukemic recipients of varicella vaccine who had 1 or > 1 dose of varicella vaccine and in those who did or did not have a household exposure to varicella was determined. A Kaplan-Meier life-table analysis revealed that the incidence of zoster was lower in those given > 1 dose of vaccine (P < .05). A Cox proportional hazards analysis showed that both household exposure to varicella and receipt of > 1 dose of vaccine were highly protective (P < .01) against zoster. Thus, the risk of zoster is decreased by reexposure to varicella-zoster virus, either by vaccination or by close exposure to varicella.     

Effects of ternary additions on the thermoelastic martensitic transformation of NiAl

Nickel-rich β-NiAl alloys, which are potential materials for high-temperature shape-memory alloys, show a thermoelastic martensitic transformation, which produces their shape memory effect. However, the transformation to Ni₅Al₃ phase during heating of NiAl martensite can interrupt the reversible martensitic transformation; consequently, the shape memory effect in NiAl martensite might not appear after heating. The phase transformation process in binary Ni-(34 to 37)Al martensite was investigated by differential thermal analysis (DTA) method, and we found that the condition of reversible martensitic transformation was not the β → Ni₅Al₃ transformation, but rather the M → Ni₅Al₃ transformation occurring at 250 °C to 300 °C. Therefore, the transformation temperature of M → Ni₅Al₃ determined the highest operating temperature for the shape memory effect. For verifying the critical temperature, the phase transformation process was investigated for eight ternary Ni-33Al-X alloys (X=Cu, Co, Fe, Mn, Cr, Ti, Si, and Nb). Only Ti, Si, and Nb additions were found to be effective in dropping the M _s temperature, and they facilitated the shape memory effect in Ni-33Al-X alloys. In particular, the addition of Si and Nb raised the transformation temperature of M → Ni₅Al₃, a potentially beneficial effect for shape memory at higher temperatures. This article is based on a presentation made in the symposium entitled “Fundamentals of Structural Intermetallics,” presented at the 2002 TMS Annual Meeting, February 21–27, 2002, in Seattle, Washington, under the auspices of the ASM and TMS Joint Committee on Mechanical Behavior of Materials.     

An efficient implementation of surface impedance boundaryconditions for the finite-difference time-domain method

An efficient way to implement the surface impedance boundary conditions (SIBC) for the finite-difference time-domain (FDTD) method is presented in this paper. Surface impedance boundary conditions are first formulated for a lossy dielectric half-space in the frequency domain. The impedance function of a lossy medium is approximated with a series of first-order rational functions. Then, the resulting time-domain convolution integrals are computed using recursive formulas which are obtained by assuming that the fields are piecewise linear in time. Thus, the recursive formulas derived here are second-order accurate. Unlike a previously published method [7] which requires preprocessing to compute the exponential approximation prior to the FDTD simulation, the preprocessing time is eliminated by performing a rational approximation on the normalized frequency-domain impedance. This approximation is independent of material properties, and the results are tabulated for reference. The implementation of the SIBC for a PEC-backed lossy dielectric shell is also introduced     

Cerebral blood flow relationships associated with a difficult tone recognition task in trained normal volunteers

Tone recognition is partially subserved by neural activity in the right frontal and primary auditory cortices. First we determined the brain areas associated with tone perception and recognition. This study then examined how regional cerebral blood flow (rCBF) in these and other brain regions correlates with the behavioral characteristics of a difficult tone recognition task. rCBF changes were assessed using H2(15)O positron emission tomography. Subtraction procedures were used to localize significant change regions and correlational analyses were applied to determine how response times (RT) predicted rCBF patterns. Twelve trained normal volunteers were studied in three conditions: REST, sensory motor control (SMC) and decision (DEC). The SMC-REST contrast revealed bilateral activation of primary auditory cortices, cerebellum and bilateral inferior frontal gyri. DEC-SMC produced significant clusters in the right middle and inferior frontal gyri, insula and claustrum; the anterior cingulate gyrus and supplementary motor area; the left insula/claustrum; and the left cerebellum. Correlational analyses, RT versus rCBF from DEC scans, showed a positive correlation in right inferior and middle frontal cortex; rCBF in bilateral auditory cortices and cerebellum exhibited significant negative correlations with RT These changes suggest that neural activity in the right frontal, superior temporal and cerebellar regions shifts back and forth in magnitude depending on whether tone recognition RT is relatively fast or slow, during a difficult, accurate assessment.     

Synthesis of ultrafine LiCoO2 powders by the sol-gel method

Ultrafine high-temperature (HT) LiCoO₂ powders were synthesized by the sol-gel method using polyacrylic acid (PAA) as a chelating agent. The decomposition process of the gel precursor was examined to determine the crystallization temperature and the dependence of the physicochemical properties of HT-LiCoO₂ powders on the PAA quantity was extensively investigated. Polycrystalline HT-LiCoO₂ powders, composed of very uniformly sized ultrafine particulates with an average particle size of 30–50 nm and a specific surface area of 2.3–17 m²g^–1, could be obtained at the lower calcination temperature of 550 °C and the shorter calcination time of 1 h compared to the solid-state reaction.     

Temporary antibiotic-loaded cemented prosthesis for two-stage septic hip arthroplasty

BACKGROUND AND OBJECTIVES: Myofascial pain is the leading cause of chronic low back pain and in most cases can be successfully resolved with trigger point injections of local anesthetics. This type of pain can exist during pregnancy and exceed the analgesia provided by an epidural for labor. METHODS: A 31-year-old primiparous woman received an epidural infusion for labor analgesia. Despite complete resolution of labor pain and a solid, bilateral T10 block, the patient reported discomfort at two discrete locations in her right lumbar paraspinous muscle. RESULTS: The administration of local anesthetic via trigger point injections resulted in successful palliation of the myofascial pain. CONCLUSIONS: Myofascial pain can be an etiology of back pain in the parturient. Trigger point injections, even when used concomitantly with a functioning epidural infusion, can be a valuable aid for the provision of complete analgesia.