A web-based teaching program for laboratory diagnosis of coagulation disorders.

OBJECTIVE: To implement an interactive program for teaching coagulation disorders on the World Wide Web. DESIGN AND RESULTS: The core materials in this program were derived from a personal computer software program previously designed by the authors. Three modules were developed in this program: (1) a coagulation profile to display typical results of coagulation screening tests for each disorder; (2) a differential diagnosis module to generate a list of diagnoses that fit the test results in a given case; and (3) a synopsis of coagulopathy and therapy to provide essential information on disorders and therapeutic options. A total of 41 coagulation disorders were included in the knowledge base. CONCLUSIONS: Since the World Wide Web is increasingly more accessible to computer users, it has become an ideal medium for teaching purposes. Our experience with this program in teaching medical students and pathology residents at our institution has been very encouraging.

Worst headache and subarachnoid hemorrhage: prospective, modern computed tomography and spinal fluid analysis.

STUDY OBJECTIVE: This study investigated the hypothesis that modern computed tomographic (CT) imaging is sufficient to exclude subarachnoid hemorrhage (SAH) in patients with severe headache. METHODS: All 38,730 adult patients who presented to Hermann Hospital in Houston, Texas, during a 16-month period were prospectively screened to detect those with "the worst headache of my life." Two neuroradiologists blinded to the study hypothesis interpreted the CT scans. Patients with negative scans underwent comprehensive cerebrospinal fluid (CSF) analysis including cell count in first and last tubes, visual and spectrophotometric detection of xanthochromia, and CSF D-dimer assay. RESULTS: A chief complaint of headache was elicited in 455 patients, and 107 of these had "worst headache" and were enrolled in the study. CT-confirmed SAH was found in 18 of the 107 (17%). Only 2 patients (2.5%, 95% confidence interval, .3% to 8.8%) had SAH detected by CSF analysis among those with negative CT imaging result. CSF spectrophotometric detection was the most sensitive test for blood. Three patients with less than 6 red blood cells in tube 1 had positive spectrophotometric results, but in all 3, tube 4 was negative on spectrophotometric analysis, suggesting a high false-positive rate. CONCLUSION: Modern CT imaging is sufficient to exclude 97.5% of SAH in patients presenting to the ED with "worst headache" symptoms.

Asbestos and silica-induced changes in human alveolar macrophage phenotype.

The mechanism by which fibrogenic particulates induce inflammation that can progress to lung fibrosis is uncertain. The alveolar macrophage (AM) has been implicated in the inflammatory process because of its function and reported release of inflammatory mediators when isolated from fibrotic patients. It has been recently shown that fibrogenic, but not nonfibrogenic, particulates are highly potent in inducing apoptosis of human AM. In this study, we tested the hypothesis that fibrogenic particulates could shift the phenotypic ratio of human AM to a more inflammatory condition. The macrophage phenotypes were characterized by flow cytometry targeting the RFD1 and RFD7 epitopes. Results demonstrated that chrysotile and crocidolite asbestos, as well as crystalline silica, but not titanium dioxide or wollastonite, increased the RFD1+ phenotype (inducer or immune activator macrophages) and decreased the RFD1+ RFD7+ phenotype (suppressor macrophages). These results provide a mechanistic explanation that may link apoptosis (namely, suppressor macrophages) to a shift in the ratio of macrophage phenotypes that could initiate lung inflammation.

Differentiation of T-cell lymphoma from Hodgkin's disease. Mitotic rate and S-phase analysis.

Flow cytometric DNA and proliferative compartment (S + G2M) analysis was performed on lymph nodes from 37 patients with Hodgkin's disease (HD) and on 16 lymph nodes plus 6 extranodal biopsies from 22 patients with peripheral T-cell lymphomas (PTCLs). The mitotic rate per 20 high-power fields (HPFs) was also determined for each case. The PTCLs showed significantly higher proliferative activity than the HD cases, as evidenced by a mean S + G2M of 12.0% versus 5.0% for HD and a median mitotic rate of 27 versus 5 mitoses per 20 HPFs in the HD cases. Because morphologic distinction, particularly of mixed cellularity HD (HDMC), from the diffuse small cleaved cell (DSCCL) or mixed cell (DMCL) pattern of PTCL may at times be difficult, these subgroups were compared separately. The 2 cases of DSCCL plus 12 of DMCL yielded a higher proportion of S-phase cells than the 9 HDMC cases with S + G2M means of 9.9% versus 3.3% and a higher mitotic rate, median 21 versus 7 per 20 HPFs. These findings suggest that S-phase determination and mitotic rate provide additional parameters in discriminating PTCL from HD in the most histologically similar cases.