Heterogeneity of clonal expansion and maturation-linked mutation acquisition in hematopoietic progenitors in human acute myeloid leukemia.

Recent technological advances led to an appreciation of the genetic complexity of human acute myeloid leukemia (AML), but underlying progenitor cells remain poorly understood because their rarity precludes direct study. We developed a co-culture method integrating hypoxia, aryl hydrocarbon receptor inhibition and micro-environmental support via human endothelial cells to isolate these cells. X-chromosome inactivation studies of the least mature precursors derived following prolonged culture of CD34(+)/CD33(-) cells revealed polyclonal growth in highly curable AMLs, suggesting that mutations necessary for clonal expansion were acquired in more mature progenitors. Consistently, in core-binding factor (CBF) leukemias with known complementing mutations, immature precursors derived following prolonged culture of CD34(+)/CD33(-) cells harbored neither mutation or the CBF mutation alone, whereas more mature precursors often carried both mutations. These results were in contrast to those with leukemias with poor prognosis that showed clonal dominance in the least mature precursors. These data indicate heterogeneity among progenitors in human AML that may have prognostic and therapeutic implications.

Can simple radiographs be predictive of total hip dislocation?

The usefulness of angles measured on standardized radiographs to determine acetabular position and predict dislocation after primary total hip arthroplasty (THA) was reviewed retrospectively. Seventy-four patients (97 primary THAs) were reviewed. All patients underwent a standardized protocol of postoperative radiographs which included an anteroposterior view of the pelvis and a cross-table lateral radiograph of the hip. Two angles were measured to define acetabular position: the abduction angle was measured on the anteroposterior radiograph and the version angle was measured on the cross-table lateral radiograph. The values for these angles were compared in a group of known dislocating THAs (7 hips) and a control group of stable THAs (90 hips). These radiographic measurements were also assessed for their reproducibility. The values for the abduction and version angles were not significantly different between the two groups. The values for abduction and version angles for a given hip, from one examination to another, were reproducible. Neither the abduction nor the version angle was a predictor of dislocation.

Cigarette smoking, physical fitness, and injuries in infantry soldiers.

Reliable data on the impact of physical training on light infantry units in terms of injuries and time loss are sparse. This study evaluated a light infantry unit (n = 181) prospectively and followed it throughout one year of infantry training and operations. Fifty-five percent of the soldiers (n = 101) experienced one or more injuries. Eighty-eight percent of the injuries were training-related conditions, which resulted in 1,103 days of limited duty. Lower extremity overuse injuries were the most common type of injury documented. Fractures accounted for the greatest number of days of limited duty. Risk factors for training-related injuries identified by this study were cigarette smoking, high percentage of body fat, extremely high or low body mass index, low endurance levels, and low muscular endurance levels (sit-ups). Logistic regression showed that cigarette smoking and low endurance levels were independent risk factors for training injuries. These data indicate that the incidence of training-related injuries in infantry units is high. A number of modifiable injury risk factors were identified, suggesting that many of these injuries may be preventable.

Incidence of Branhamella catarrhalis in the sputa of patients with chronic lung disease.

The incidence of Branhamella catarrhalis in the respiratory tract of adults, especially in the United States, is not known. During the 30-month period from January 1983 to June 1985, 4180 sputum and endotracheal samples from patients in a hospital for chest diseases were evaluated. All samples were acceptable for Gram-stain analysis and/or culture based on published cellular criteria. Using primarily Gram-stain directed cultures, 220 isolates of B. catarrhalis were identified in 180 patients, being present in 5.3% of all sputum cultures and 11.5% of those positive for a pathogen. B. catarrhalis was the fourth most common pathogen identified. It was found in pure culture (124) and mixed culture (96), the latter usually in association with Haemophilus influenzae or Streptococcus pneumoniae. Of the 220 B. catarrhalis isolates, 158 (71.8%) were positive for beta-lactamase. The number and incidence of B. catarrhalis varied, with the organism being most prevalent during the winter months. Despite its frequent presence in sputum, B. catarrhalis was not recovered from pleural fluid or blood during the same period. This study demonstrates the frequent presence of B. catarrhalis in the sputum of adults with chronic lung disease, although the role of this organism as a pathogen was not determined.

Bone marrow metastases in disseminated alveolar rhabdomyosarcoma: case report with ultrastructural study and review.

A case of desseminated alveolar rhabdomyosarcoma in an 18-year-old male with leuco-erythroblastic anaemia is described. Numerous bizarre malignant cells, including frequent multinucleated giant cells, were seen in bone marrow aspirates, and osteolytic lesions appeared late in the clinical course. The primary site of the neoplasm remained undertermined during life and also at necropsy, which revealed minute pulmonary metastases and extensive lymph nodal, pleural and skeletal deposits. The diagnosis was confirmed on necropsy tissue by ultrastructural examination which demonstrated numerous thin (5 nm) and thick (15 nm) intracytoplasmic filaments in tumour cells, sometimes organized in bundles; scattered dense Z-band-like bodies, and rod-shaped structures were also seen. The fine structure of the rhabdomyosarcoma in the present case is compared with previous ultrastructural studies. Elongated, thick intracytoplasmic filaments whose diameter corresponds to that of myosin myofilaments are strong evidence for rhabdomyoblastic differentiation and are considered to be the sine qua non of a positive electron microscopic diagnosis of rhabdomyosarcoma. Orgaized bundles of filaments and Z-band-like dense bodies are usually present, and rod-shaped structures are found infrequently, but none of these are necessary for the ultrastructural diagnosis.