Biomedical subjects
A Chang
Publications and source records attributed to A Chang.
Anemia in the newborn due to intrauterine fetomaternal transfusion.
Explore the source record for details and available documents.
Electron-microscopic evidence for reactions of axial filaments of Leptospira with IgM and IgG antibodies.
Serological identifications of structural components of leptospires have not previously been reported although morphological and antigenic studies have been carried out extensively.The antigenic activity of isolated axial filaments was characterized by direct electron-microscopic visualization of immune precipitates with fractionated antisera. The precipitates were composed of axial filament with IgM or IgG antibodies attached.The axial filament is the first structural component of leptospires to be identified serologically. Knowledge of the pattern of cross-reactivity of this axial filament antigen among various serotypes may be of value in helping to establish a new system of classification based on specific antigens rather than the current system using reciprocal agglutinin-absorption tests, which measures the resultant of many antigens.
The aetiology of upper respiratory tract infections seen in general practice in Sydney.
Explore the source record for details and available documents.
Effect of stretch on the isolated cat sinoatrial node.
Explore the source record for details and available documents.
Relative increased incidence of childhood Hodgkin's disease in Peru.
Explore the source record for details and available documents.
Comparison of urographic and cholegraphic contrast enhanced CT liver scanning.
Explore the source record for details and available documents.
Multilevel modeling of fetal and placental growth using echo-planar magnetic resonance imaging.
OBJECTIVE: To quantify longitudinal increases in fetal, fetal liver, and fetal brain volume using echo-planar magnetic resonance imaging and to quantify the results using appropriate statistical modeling. METHODS: Fifty-six singleton fetuses were studied using echo-planar (snap-shot) magnetic resonance imaging, between 19 weeks and term. They were assessed at a variety of different gestations and on a different number of occasions, thereby requiring multilevel statistical modeling to analyze the pattern of fetal growth. RESULTS: Fetal volume varied according to the following equation: square root (radical) [fetal volume]=-37.71+2.17 x gestational age (GA)-0.004 x GA(2). The equation for fetal liver volume was radical[fetal liver volume]=9.47+0.56 x GA-0.02 x GA(2), for fetal brain volume was radical[fetal brain volume]=15.50+0.69 x GA-0.014 x GA(2), and for placental volume radical[placental volume]=28.54+0.95 x GA-0.039 x GA(2), where GA is the gestational age in weeks -30. CONCLUSION: The assessment of fetal, fetal organ, and placental volume was feasible using echo-planar magnetic resonance imaging from 20 weeks to term. Multilevel statistical modeling can be applied to analyze sets of data with different measurements on different occasions. This information is useful clinically to assess abnormal fetal growth.
Familial cutaneous mastocytosis.
Cutaneous mastocytosis appears to occur sporadically; however, familial inheritance has been reported in 50 families since the mid-1880s. We report four cases of telangiectasia macularis eruptiva perstans (TMEP) occurring in three generations of a family. Whereas most patients with TMEP manifest in adulthood, all of the members of this family developed initial lesions during childhood. This is the third documented instance of familial mastocytosis affecting members of three generations, and the first report of familial TMEP. Although the inheritance pattern is unknown, the presentation of disease in this family further supports the hypothesis of an autosomal dominant mode of transmission with incomplete penetrance.
Nipple feeding for preterm infants with bronchopulmonary dysplasia.
OBJECTIVE: To examine the influence of an infant's physical condition on nipple-feeding practices and the contribution of the infant's age at complete nipple feeding to dietary intake and somatic growth outcomes. DESIGN: A retrospective, correlational study. SETTING: Two Level III nurseries. PARTICIPANTS: Records of 55 preterm infants with bronchopulmonary dysplasia. MAIN OUTCOME MEASURES: The infant's intake of kcal/kg on Day 1 of complete nipple feeding and the weight gain per day between complete nipple feeding and discharge. RESULTS: Gestational age and days on mechanical ventilation, continuous positive airway pressure, or supplementary oxygen influenced age at start and at completion of nipple feeding (p < .05). The infant's weight when nipple feeding was introduced was the primary determinant of age at introduction of nipple feeding (B = .50, p < .001). The physical condition variables did not influence the transition time from introduction of nipple feeding to complete nipple feeding. Neither the physical condition variables nor the feeding practice variables contributed to caloric intake. Weight gain between the time of complete nipple feeding and hospital discharge was less for infants who were on supplementary oxygen longer and who were older when completely nipple fed (p < .01).
Identification and molecular characterization of five novel kallikrein gene 13 (KLK13; KLK-L4) splice variants: differential expression in the human testis and testicular cancer.
The kallikrein gene family is comprised of genes that have either established or potential applications in prostate and breast cancer diagnostics. New members of the human kallikrein gene family have been recently identified. By using the positional candidate gene approach, we were able to clone a novel human serine protease gene that maps to chromosome 19q13.3-q13.4, the location of the kallikrein gene family. We named this gene KLK-L4 (now also known as KLK13). Here, we describe the identification of five new KLK-L4 splice variants which are not expressed in any other tissue except the human testis. We have further established that these splice variants can be detected in normal testis but not in the adjacent matched testicular tumors. In addition, differential expression of the KLK-L4 gene was found in various histological types of testicular cancer. Our results suggest that the KLK-L4 gene is expressed in normal and cancerous testicular tissue; however, its five variants are all expressed in normal tissue but not in testicular tumors. The physiological relevance of these variants and the implications of their differential expression between cancerous and normal tissues are currently unknown.
Bone response to functioning implants in dog mandibular alveolar ridges augmented with distraction osteogenesis.
The specific aim of this study was to determine the response of alveolar bone after it was augmented vertically using distraction osteogenesis and subsequently loaded with implant restorations. Four dogs each had four implants placed horizontally into an edentulous mandibular quadrant and, after integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the device was stabilized with light cured resin. Following bone fill confirmation of the distraction gap at 10 weeks, two implants were placed into the ridges, one in distracted bone and one in nondistracted bone. After 4 months for implant integration, freestanding prostheses were fabricated. Crestal bone levels were evaluated throughout the period of function. Animals were sacrificed after 1 year of loading, for histologic evaluation of the bone. The vertical ridge augmentation averaged 8.85 +/- 1.05 mm after 10 weeks of healing following distraction, without change over 1 year of implant loading. Histologic examination showed that bone had formed between the distracted segments, creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone and the lingual and labial nondistracted cortical bone. The presence of the dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis maintained bone and were functional for the length of this study.