Morphological basis of tolerance to ozone

The purpose of this research was to study Type 1 epithelial cells in the ozone (O3)-tolerant lung epithelium. Rats were made tolerant by exposure to 0.5 ppm O3 for 2 days and allowed to recover in air. Reexposure to a lethal concentration of O3 (6 ppm) at 3, 7, and 15 days of recovery revealed that tolerance was present at 3 days but almost absent at 7 and 15 days of recovery. Using Type 2 cell proliferation as a means of quantitating Type 1 cell injury, it was observed that when the preexposed rats were reexposed to 0.5 ppm at 3, 7, and 15 days, very little Type 1 cell injury occurred at 3 days. However, at 7 and 15 days the amount of Type 1 cell injury was the same as that associated with the original exposure. To determine whether there was any change in the alveolar epithelial cell populations between the periods of tolerance (3 days) and its decline (7 and 15 days), the percentage of tritiated thymidine [( 3H]TdR-labeled Type 1 and 2 cells at these times were determined. There was a significant decrease in [3H]TdR-labeled Type 1 and 2 cells between the third and fifteenth days of recovery as excess cells were sloughed off and the tissue returned to normal. Using electron microscopic morphometry, Type 1 and 2 cells were then studied during the decline of tolerance. No change was found in the morphology of Type 2 cells; however, the morphology of Type 1 cells revealed a 58% decrease in surface area and a 25% increase in the arithmetic mean thickness when tolerance was present at 3 days. As tolerance declined (7 and 15 days), Type 1 cell morphology returned to normal. It was concluded that tolerance exists when the surface area of a cell exposed to a particular concentration of ozone is small enough so that the existing antioxidant mechanism contained within that cell volume can protect it from damage.     

The role of seizures in reversible posterior leukoencephalopathy.

We report two hypertensive females, one suffering from chronic renal failure and on regular dialysis, the other with eclampsia. Both developed new onset seizures. The patients' MRI of brain showed signals consistent with the reversible posterior leukoencephalopathy syndrome (RPLES), but with the signals seen only in the hemisphere where the seizures predominated. The anatomic correlation of the clinical and imaging findings supports the notion that seizures have a major role in the genesis and evolution of RPLES.     

Femoral head avascular necrosis: correlation of MR imaging, radiographic staging, radionuclide imaging, and clinical findings

To better correlate the appearance of avascular necrosis (AVN) of the femoral head on magnetic resonance (MR) images with the stage of disease, MR images of 56 proved AVN lesions were compared with staging from corresponding radiographs (n = 56), Tc-99m scans (n = 41), and grade of symptoms (n = 28). Fractures complicating AVN were seen in 28 (50%) of 56 radiographs (radiographic stages III-V). With long repetition (TR) and echo delay (TE) times, a characteristic "double line sign" consisting of high signal intensity inside a low-intensity peripheral rim was seen in 45 lesions (80%). The central region within the rim was isointense with marrow fat on both short and long TR and TE images in 20 (71%) of 28 lesions uncomplicated by fracture (stages I-II) but in only four (14%) of 28 stage III-V lesions (P less than .001). Symptoms were least severe in lesions isointense with fat and most severe in lesions with low-signal central regions at short and long TRs and TEs. The peripheral double line sign on long TR/TE images may add specificity to the diagnosis of AVN by MR imaging. A chronologic pattern of central MR signal features is presented which may allow staging of AVN by MR imaging.     

The role of community pharmacists in depression management: a survey of attitudes,practices and perceived barriers

International Journal of Clinical Pharmacy - Background Community pharmacists play a significant role in depression care. Depression is a health priority in national health strategies around the...     

Adverse effects of arsenic exposure on uterine function and structure in female rat

The present investigation examined the adverse effects of arsenic exposure on uterine function and structure of female rat at 56 days of age, exposed to different doses (50, 100, and 200 ppm) of sodium arsenite in drinking water at immature age (28 days) for 28 days. Dose-dependent decrease (P<0.001) was observed in mean uterine weight and length in all treated groups compared to control. Higher arsenic deposition was found in uterine tissue against increased doses of arsenite. Arsenite treatment altered the histomormphology of the uterus. Uterine epithelium in 50 ppm group was lined by cuboidal cells instead of columnar cells observed in control epithelium. In 100 and 200 ppm groups, no demarcation was observed between epithelial cells and endometrial stroma. No basement membrane was seen in these groups; even in 50 ppm, basement membrane was disturbed. The endometrial stroma in 100 and 200 ppm groups was very dense in appearance and contained irregular-shaped cells. In myometrium, loosening of cells was observed in 100 and 200 ppm groups. Dose-dependent decrease (P<0.001) was observed in mean uterine diameter, epithelial height, thickness of endometrium, myometrium, and in plasma levels of estradiol, progesterone, FSH and LH in all the treatment groups compared to control. In summary, arsenic is a major threat to female reproductive health acting as a reproductive toxicant and as an endocrine disruptor, restricted the function and structure of uterus, by altering the gonadotrophins and steroid levels, not only at high dose concentration but also at low (50 ppm) levels, when they become mature.