A global marine sedimentary response to the end-Permian mass extinction: Examples from southern Turkey and the western United States

The end-Permian mass extinction greatly diminished marine diversity and brought about a whole-scale restructuring of marine ecosystems; these ecosystem changes also profoundly affected the sedimentary record. Data presented here, attained through facies analyses of strata deposited during the immediate aftermath of the end-Permian mass extinction (southern Turkey) and at the close of the Early Triassic (southwestern United States), in combination with a literature review, show that sedimentary systems were profoundly affected by: (1) a reduction in biotic diversity and abundance and (2) long-term environmental fluctuations that resulted from the end-Permian crisis. Lower Triassic strata display widespread microbialite and carbonate seafloor fan development and contain indicators of suppressed infaunal bioturbation such as flat-pebble conglomerates and wrinkle structures (facies considered unusual in post-Cambrian subtidal deposits). Our observations suggest that depositional systems, too, respond to biotic crises, and that certain facies may act as barometers of ecologic and environmental change independent of fossil assemblage analyses. Close investigation of facies changes during other critical times in Earth history may serve as an important tool in interpreting the ecology of metazoans and their environment.

Deoxyribonucleic acid content as an indicator of progression of squamous cell carcinogenesis in the esophagus: comparative analysis on imprint-cytospin and tissue section preparation.

BACKGROUND: The purpose of this study was to explore the potential use of image analysis on tissue sections preparation as a predictive marker of early malignant changes during squamous cell (SC) carcinogenesis in the esophagus. Results of DNA ploidy quantification on formalin-fixed, paraffin-embedded tissue using two different techniques were compared: imprint-cytospin and 6 microm thick tissue sections preparation. METHODS: This retrospective study included 26 surgical specimens of squamous cell carcinoma (SCC) from patients who underwent surgery alone at the Department of Surgery in CHUV Hospital in Lausanne between January 1993 and December 2000. We analyzed 53 samples of healthy tissue, 43 tumors and 7 lymph node metastases. RESULTS: Diploid DNA histogram patterns were observed in all histologically healthy tissues, either distant or proximal to the lesion. Aneuploidy was observed in 34 (79%) of 43 carcinomas, namely 24 (75%) of 32 early squamous cell carcinomas and 10 (91%) of 11 advanced carcinomas. DNA content was similar in the different tumor stages, whether patients presented with single or multiple synchronous tumors. All lymph node metastases had similar DNA content as their primary tumor. CONCLUSIONS: Early malignant changes in the esophagus are associated with alteration in DNA content, and aneuploidy tends to correlate with progression of invasive SCC. A very good correlation between imprint-cytospin and tissue section analysis was observed. Although each method used here showed advantages and disadvantages; tissue sections preparation provided useful information on aberrant cell-cycle regulation and helped select the optimal treatment for the individual patient along with consideration of other clinical parameters.

Early effects of intravitreal triamcinolone on macular edema: mechanistic implication.

PURPOSE: To evaluate the early effects of intravitreal triamcinolone acetonide (TA) on cystoid macular edema associated with retinal vein occlusion and diabetic retinopathy. DESIGN: Prospective, interventional, small case series. PARTICIPANTS: Four patients with cystoid macular edema resulting from retinal vein occlusion or diabetic retinopathy of more than 4 months' duration and evaluated as suitable for treatment with intravitreous injection of TA. METHODS: After ophthalmic examination, including visual acuity assessment, intraocular pressure (IOP) measurement, and optical coherence tomography (OCT) analysis, the patients received a single intravitreal injection of 4 mg TA. After the injection, consecutive visual acuity assessment, IOP measurement, and OCT analysis were performed after 1 hour, 6 hours, 1 week, and 2 weeks. MAIN OUTCOME MEASURE: Optical coherence tomography assessment of macular thickness. RESULTS: Macular thickness and edema initially were reduced as early as 1 hour after TA injection. A further continuous decrease was observed during the 2 weeks after treatment. CONCLUSIONS: This rapid effect of intravitreal TA is interpreted to indicate that nongenomic effects on retinal or retinal pigment epithelial cell membranes, or both, may be responsible for this phenomenon. Identifications of these mechanisms may help design alternative, more specific drugs for the treatment of macular edema.