Heating patterns of microwave applicators in inhomogeneous arm and thigh phantoms.

Heating rate (HR) patterns in cylindrical structures were studied with inhomogeneous limb phantoms. These phantoms, arm and thigh models consisting of fat, bone, and muscle material, were heated with Clini-Therm L, M, and MS applicators at 915 MHz. The thigh model is 18 cm in diameter with 2.65-cm-thick fat on the outside and a 4-cm-diam bone in the center. The arm model is 9 cm in diameter with 1.35-cm-thick fat and 2-cm-diam bone. All models are 29 cm long with phantom muscle in the space between fat and bone and were heated with their long axes parallel or perpendicular to the E field. HR patterns in the transverse and longitudinal planes were obtained thermographically. A large water bolus, with the water channels parallel to the E field, was used in every case. In the thigh model, maximum heating was in the muscle for both L and M applicators when the E field was parallel to the long axis. When it was perpendicular, the maximum heating occurred in the fat layer. However, the peak HR in the fat remained about the same for both E field orientations. For the small applicator, heating was mostly in the fat, and the two field orientations did not cause much difference in the heating pattern. In the arm model, the maximum heating of all three applicators occurred mostly in the muscle for both E-field orientations. However, the maximum HR was reduced by a factor of 2 to 3 when the E field was perpendicular rather than parallel to the long axis.(ABSTRACT TRUNCATED AT 250 WORDS)     

The significance of small erythrocytes.

Small erythrocytes (mean corpuscular volume less than 80 mu-3 by the Coulter Model S) were found in 222 (2.75%) of 8,086 consecutive patients admitted to a large suburban general hospital. Forty-five (20.3%) of these 222 patients had laboratory findings consistent with thalassemia. Seventy-six (31.2%) were found to be iron deficient. Patients whose hemoglobin values were below 9.0 Gm. per 100 ml. were more likely to be iron deficient. The hemoglobin A2 values were significantly lower in iron-deficient than in non-iron-deficient patients. Although the mean corpuscular volume is much lower and the erythrocyte count is higher in thalassemia than in iron deficiency, hematologic values obtainable from the Counlter S (such as MCV, erythrocyte count, and hemoglobin) alone are not valuable in differentiating thalassemia from iron deficiency.     

Genetic changes in neoplasms arising in congenital melanocytic nevi: differences between nodular proliferations and melanomas

Large congenital melanocytic nevi (CMN) are at an increased risk of developing melanoma. Several forms of secondary proliferations can arise in congenital nevi on rare occasions. Although some of these closely resemble melanoma both clinically and histologically, metastasis is rare. We used comparative genomic hybridization to analyze chromosomal aberrations in different types of proliferations arising in CMN and compared them to typical congenital nevi, clear-cut melanomas arising in congenital nevi, as well as primary cutaneous melanomas that were not associated with a CMN. Cases of CMN and CMN with secondary proliferations were assigned to six groups according to the predominant histological pattern: group I, bland congenital nevi (n = 6); group II, congenital nevi with foci of increased cellularity (n = 4); group III, CMN with a proliferation simulating superficial spreading melanoma in situ (n = 3); group IV, CMN with a proliferation simulating nodular melanoma (n = 9); group V, proliferating neurocristic hamartoma (n = 1); and group VI, melanoma arising in congenital nevus (n = 6). No aberrations were found in groups I to III, whereas seven of nine cases of group IV, and one of one case of group V, showed aberrations. In group IV six of seven cases with aberrations (86%) showed numerical aberrations of whole chromosomes exclusively. This pattern differed significantly from the findings in melanoma that arose within CMN (n = 6), group VI, or independent of CMN (n = 122) in which only 5% showed numerical changes only. The single case in group V showed aberrations similar to melanoma. The finding of frequent numerical chromosomal aberrations in atypical nodular proliferations arising in CMN identifies these as clonal neoplasms with a genomic instability consistent with a mitotic spindle checkpoint defect. This difference compared to the aberration pattern found in melanoma might explain their more benign clinical behavior and may be of diagnostic value in ambiguous cases.     

ST2作为Th2细胞亚群标志以及其与支气管哮喘的关系的研究

各自主要分泌IFN γ和IL 4的Th1和Th2亚群 ,与临床疾病的关系十分密切。如何从表面标志上加以区分是一项迫切需要解决的问题。ST2是近年来提出的Th2细胞的稳定标志物。本工作在体外成功地诱导人脐带血T细胞向Th1或Th2分化的基础上 ,应用逆转录PCR分析了ST2mRNA的表达特点。证实ST2在人Th2细胞上的选择性表达。为了探索ST2、Th2与支气管哮喘的关系 ,本工作进一步检测了正常人和支气管哮喘患者外周血单个核细胞中 β actin、ST2以及IFN γ和IL 4的mRNA水平。结果显示 :支气管哮喘患者ST2mRNA水平升高 ,IL 4水平也明显升高 ,但IFN γ无变化。这提示ST2作为Th2细胞的标志物 ,有可能成为Th2极化性疾病如哮喘发病机制研究的一个参考性标志 ,至于ST2是否有可能作为治疗的靶分子 ,有待进一步探讨     

Rises in antibody to human herpesvirus 6 detected by enzyme immunoassay in transplant recipients with primary cytomegalovirus infection.

Immunoglobulin G to human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) in sera from solid organ recipients was measured by an enzyme-linked immunoassay (ELISA) before and after transplant. The HHV-6 ELISA was developed from glycine extracts of HHV-6-infected and uninfected HSB-2 cells. At a serum dilution of 1:500, 80 (91%) of 88 recipients were seropositive for HHV-6 before transplant, while only 14 (16%) were seropositive for CMV. Posttransplant HHV-6 serologic rises were observed in 38 (43%) recipients; rises in 25 of these recipients were associated with primary CMV infection. Titration of sera revealed much higher HHV-6 titer rises among those with primary CMV infection than among those with CMV reactivation or with no CMV infection. Elevated HHV-6 antibody titers persisted for up to 2 years after primary CMV infection. No correlation was noted between CMV and HHV-6 antibody titers in individual serum samples.     

Genetic linkage of the tricho-dento-osseous syndrome to chromosome 17q21

Tricho-dento-osseous syndrome (TDO), MIM# 190320, is transmitted as a highly penetrant autosomal dominant trait that is characterized by variable clinical expression. The principal clinical features include kinky/curly hair in infancy, enamel hypoplasia, taurodontism, as well as increased thickness and density of cranial bones. Possible genetic linkage has been reported for TDO with the ABO blood group locus, but the gene defect remains unknown. We have identified four multiplex families (n = 63, 39 affected, 24 unaffected) from North Carolina segregating TDO. We previously have excluded a major locus for TDO in the ABO region for these families. Utilizing a genome-wide search strategy, we obtained conclusive evidence for linkage of the TDO syndrome locus to markers on chromosome 17q21 (D17S791, Z max = 10.54, Theta = 0.00) with no indication of genetic heterogeneity. Multipoint analysis suggests the TDO locus is located in a 7 cM chromosomal segment flanked by D17S932 and D17S941. This finding represents the first step towards isolation and cloning of the TDO gene. Identification of this gene has important implications for understanding normal and abnormal craniofacial development of hair, teeth and bone.      

Myosin light chain kinase modulates hypotonicity-induced Ca2+ entry and Cl– channel activity in human cervical cancer cells

Hypotonicity-induced Ca2+ entry is a critical signal for the normal regulatory volume decrease in human cervical cancer cells. The aim of this study was to explore the role of myosin light chain kinase (MLCK) in the regulation of hypotonicity-induced Ca2+ signalling and Cl- channel activity. Blockade of MLCK activity by MLCK(11-19) amide, a substrate-specific peptide inhibitor, markedly attenuated hypotonicity-induced Ca2+ entry. A similar result was obtained with ML-7, a synthetic naphthalenesulphonyl derivative that inhibits the binding of ATP to MLCK. More than 85% of the activity of the volume-regulated Cl- channel was suppressed when intracellular Ca2+ was buffered to near zero in the absence of extracellular Ca2+, suggesting that hypotonicity-induced Ca2+ signalling is important for the activation of the volume-regulated Cl- channel. Intracellular dialysis with MLCK(11-19) amide or ML-7 concentration-dependently reduced the amplitude and rate of activation of the volume-regulated Cl- channel. Swelling-activated taurine transport was also inhibited concentration dependently by ML-7 and MLCK(11-19) amide with IC(50) values of 6.4 and 2.0 microM, respectively. Hypotonicity induced MLC phosphorylation which was mediated totally by MLCK and depended on Ca2+ entry. However, phosphorylated MLC per se was not involved critically in the regulation of Ca2+ entry and activation of volume-sensitive organic osmolyte/anion channels (VSOAC). We propose that MLCK has a novel function in regulating the activation of VSOAC by mediating Ca2+ entry in response to hypotonicity. This function of MLCK on Ca2+ signalling does not correlate with MLC phosphorylation.     

Missense mutation in a von Willebrand factor type A domain of the alpha 3(VI) collagen gene (COL6A3) in a family with Bethlem myopathy

The Bethlem myopathy is a rare autosomal dominant proximal myopathy characterized by early childhood onset and joint contractures. Evidence for linkage and genetic heterogeneity has been established, with the majority of families linked to 21q22.3 and one large family linked to 2q37, implicating the three type VI collagen subunit genes, COL6A1 (chromosome 21), COL6A2 (chromosome 21) and COL6A3 (chromosome 2) as candidate genes. Mutations of the invariant glycine residues in the triple-helical domain-coding region of COL6A1 and COL6A2 have been reported previously in the chromosome 21-linked families. We report here the identification of a G-->A mutation in the N-terminal globular domain-coding region of COL6A3 in a large American pedigree (19 affected, 12 unaffected), leading to the substitution of glycine by glutamic acid in the N2 motif, which is homologous to the type A domains of the von Willebrand factor. This mutation segregated to all affected family members, to no unaffected family members, and was not identified in 338 unrelated Caucasian control chromosomes. Thus mutations in either the triple-helical domain or the globular domain of type VI collagen appear to cause Bethlem myopathy.      

Evaluation of RGS4 as a candidate gene for schizophrenia.

Several studies have suggested that the regulator of G-protein signaling 4 (RGS4) may be a positional and functional candidate gene for schizophrenia. Three single nucleotide polymorphisms (SNP) located at the promoter region (SNP4 and SNP7) and the intron 1 (SNP18) of RGS4 have been verified in different ethnic groups. Positive results have been reported in these SNPs with different numbers of SNP combinatory haplotypes. In this study, these three SNP markers were genotyped in 218 schizophrenia pedigrees of Taiwan (864 individuals) for association analysis. Among these three SNPs, neither SNP4, SNP7, SNP18 has shown significant association with schizophrenia in single locus association analysis, nor any compositions of the three SNP haplotypes has shown significantly associations with the DSM-IV diagnosed schizophrenia. Our results fail to support the RGS4 as a candidate gene for schizophrenia when evaluated from these three SNP markers.     

Impact of cadaveric organ donation on Taiwanese donor families during the first 6 months after donation

OBJECTIVE: Organ donation is a complex decision for family members of Asian donors. The impact of cadaveric organ donation on both Chinese and Western donor families has not been well investigated within a cultural framework. The purposes of this study were to follow Chinese family members' appraisal of their decision to donate organs, to explore the possible negative and positive impacts of organ donation on their family life, and to determine what help they expected from healthcare providers during the first 6 months after donation. METHODS: Twenty-two family members (10 men and 12 women) of cadaveric organ donors who signed consent forms at an organ transplant medical center in Taiwan participated in this project and completed in-depth interviews during the sixth month after donation. RESULTS: Participants were 25 to 56 years old (mean = 48.15 +/- 8.31 years). The type of kinship of the participants included the donor's parents, older sister, and spouse. Subjects reported several negative impacts: worry about the donor's afterlife (86%), stress due to controversy among family members over the decision to donate (77%), and stress due to others' devaluation of the donation (45%). Positive impacts reported by the subjects included having a sense of reward for helping others (36%), having an increased appreciation of life (32%), having closer family relationships (23%), and planning to shift life goals to the study of medicine (9%). Subjects expected the transplant team to provide information about organ recipients (73%), to submit the necessary documents so that family members could receive healthcare payments from the insurance company (68%), to help resolve legal proceedings and settlements associated with accidents (64%), and to not overly publicize their decision to donate (64%). CONCLUSIONS: Although all of the subjects reported that organ donation was the right decision, the decision to donate did not protect Taiwanese donor families from negative psychocognitive bereavement. The impacts of organ donation were affected by the subject's social cultural, spiritual, and legal context and the nature of their bereavement.