Mayr, Dobzhansky, and Bush and the complexities of sympatric speciation in Rhagoletis

The Rhagoletis pomonella sibling species complex is a model for sympatric speciation by means of host plant shifting. However, genetic variation aiding the sympatric radiation of the group in the United States may have geographic roots. Inversions on chromosomes 1-3 affecting diapause traits adapting flies to differences in host fruiting phenology appear to exist in the United States because of a series of secondary introgression events from Mexico. Here, we investigate whether these inverted regions of the genome may have subsequently evolved to become more recalcitrant to introgression relative to collinear regions, consistent with new models for chromosomal speciation. As predicted by the models, gene trees for six nuclear loci mapping to chromosomes other than 1-3 tended to have shallower node depths separating Mexican and U.S. haplotypes relative to an outgroup sequence than nine genes residing on chromosomes 1-3. We discuss the implications of secondary contact and differential introgression with respect to sympatric host race formation and speciation in Rhagoletis, reconciling some of the seemingly dichotomous views of Mayr, Dobzhansky, and Bush concerning modes of divergence.     

Improved results of treatment of adult acute lymphoblastic leukemia

We designed a treatment program to improve the outcome for adults with acute lymphoblastic leukemia (ALL). Treatment included a remission- induction phase followed by intensive alternating cycles of non-cross- resistant chemotherapy and prolonged oral maintenance therapy. Eighty- one consecutive previously untreated patients were entered on this study. Ninety-four percent of patients entered complete remission. A Kaplan-Meier analysis predicts that 53% +/- 9% (SEM) of patients in remission will remain free of disease at 3 years. Neither age, sex, WBC count, nor immunophenotype had a significant effect on remission duration. This program of intensive cyclical chemotherapy has improved the disease-free survival of patients with adult ALL.     

Analysis of human platelet antigen systems in a Moroccan Berber population

The human platelet alloantigen systems HPA-1, -2, -3, -4, -5 and -6 in a Moroccan Berber population from the Amizmiz region were determined by polymerase chain reaction using sequence-specific primers (PCR-SSP). The gene frequencies obtained from these unrelated Berbers were 0 x 747 and 0 x 252 for HPA-1a and -1b; 0 x 817 and 0 x 182 for HPA-2a and -2b; 0 x 682 and 0 x 317 for HPA-3a and -3b; 1 and 0 x 0 for HPA-4a and -4b; 0 x 8616 and 0 x 1383 for HPA-5a and -5b; 1 and 0 x 0 for HPA-6a and -6b. The Berbers have the highest frequency for the 1b, 2b and 5b alleles of all the populations reported to date and also the lowest frequency for the 3b allele.     

Bowel and mesenteric injury following blunt abdominal trauma: evaluation with CT

Computed tomography (CT) used in cases of blunt abdominal trauma has been found sensitive in detection of bowel and mesenteric injuries and discrimination of operable from nonoperable candidates. In 51 patients with suspected bowel or mesenteric injury following blunt abdominal trauma, CT correctly depicted bowel hematoma or mesenteric injury in 17 of 19 nonoperable patients (89%) and severe injuries in one patient who died preoperatively. In 26 of 28 patients who underwent therapeutic laparotomy (93%), initial CT enabled identification of surgically confirmed injuries. In two cases, initial scan misinterpretation delayed diagnosis of serious bowel injuries. The correct interpretation was rendered preoperatively and at blind retrospective review. CT findings that correlated with bowel or mesenteric injury requiring surgery were free peritoneal fluid (27 of 28, 96%), mesenteric infiltration (24 of 28, 86%), thick-walled bowel (17 of 28, 61%), associated abdominal injuries (12 of 28, 43%), and free air (nine of 28, 32%). In nonoperable cases, CT scans demonstrated bowel thickening (84%) but less frequently peritoneal fluid (21%), mesenteric infiltration (26%), or associated injuries (5%). In three of four patients who underwent nontherapeutic laparotomy, preoperative CT correctly imaged the limited abdominal injuries.     

Cutaneous lymphoblastic lymphoma with pre-B markers

Two children with cutaneous convoluted lymphoblastic lymphoma are reported. Malignant cells from both patients contained cytoplasmic Mu heavy chains characteristic of pre-B-cells and expressed CALLA and la antigens as well. Most cases of convoluted lymphoblastic lymphoma are T- cell-derived neoplasms. The non-T, non-B phenotype found in these two children demonstrates that histology does not necessarily predict immunophenotype. The association of the pre-B phenotype with cutaneous lymphoma has not been previously reported, but may represent a unique clinical-histopathologic-immunologic entity that occurs in young children.