ABSTRACT
Genetic sex typing of vertebrate animals is an essential technique for research on reproductive phenomena such as sex determination of embryonic tissues. Polymerase chain reaction amplification of genomic DNA segments in the Z and W sex chromosomes has been widely used as a standard laboratory method to determine genetic sex of the chicken (Gallus gallus domesticus). However, conventional protocols for PCR determination of avian sex typically involve tedious steps of genomic DNA isolation, which often require relatively large amounts of tissue samples, and the purity of genomic DNA specimens significantly affects PCR efficiency. Moreover, detection of sex chromosome-specific PCR products by gel electrophoresis is prone to misjudgment caused by amplification of contaminating genomic DNA segments derived from tissue or DNA samples as well as previously generated PCR products. Thus, the credibility of genetic sex typing by conventional PCR-based methods that measure the relative amounts of the end product DNA amplicons critically depends on several experimental steps that are potentially vulnerable to errors. Here, we describe an optimized protocol of chicken genetic sex typing by TaqMan real-time quantitative PCR amplification of markers on the sex chromosomes. This TaqMan sex typing method accurately quantifies relative amounts of the Z and W sex chromosome markers directly from only 0.5 to 2 microL of total blood lysate without nucleic acid purification. The real-time amplification curves of the quantitative PCR reaction readily distinguished truly homozygous (ZZ) and heterozygous (ZW) sex chromosomes from contamination of the sex chromosomal DNA, ensuring highly credible sex determination. Thus, the TaqMan typing of chicken genetic sex has several advantageous features for high-throughput operation compared with conventional methods.
Subject(s)
Chickens/genetics , Sex Chromosomes , Sex Determination Analysis/veterinary , Animals , Chick Embryo , DNA/chemistry , DNA/genetics , Female , Male , Polymerase Chain Reaction/veterinaryABSTRACT
PURPOSE: An ileocecal intussusception developed in a 7-month-old infant with acute lymphoblastic leukemia (ALL) during induction therapy. Gastrointestinal complications, especially intussusception, are rare in children with ALL. PATIENT AND METHODS: The history of a 7-month-old white boy with ALL in whom an ileocecal intussusception developed 1 week into induction chemotherapy was reviewed. In addition, a literature search was performed to determine the prevalence of this complication in children with acute leukemia. RESULTS: On day 4 of induction chemotherapy for B-lineage ALL, the infant developed abdominal distension with hypoactive bowel sounds. After a barium enema and abdominal computed tomography scan, the symptoms were determined to be caused by an ileocecal intussusception. Chemotherapy was resumed 1 week after immediate surgical intervention (reduction of intussusception and resection of the "leading edge") with an uneventful post-operative recovery. Histopathologic examination of the resected edge revealed an intact mucosa with areas of necrosis in the submucosa. This was associated with a dense lymphoid infiltrate composed of mature lymphocytes and leukemic cells, edema, and focal necrosis. Despite a 1-week delay in chemotherapy, a complete remission was documented at day 32. DISCUSSION: The prevalence of intussusception in children with ALL and its possible etiology are discussed. The pathologic changes, clinical manifestations, and treatment outcome are briefly mentioned.