Computed tomography in metastatic disease of the brain

15 male undergraduates were presented with 10-sided random forms which they explored visually, or one-handed haptically, or two-handed haptically. Forms were exposed for various durations and subjects were required to draw each form immediately after its removal. The results indicated that 30 sec. of one-handed exploration and 20 and 30 sec. of two-handed exploration produced performance comparable to just 2 sec. of visual exploration. Two-handed exploration was significantly superior to one-handed exploration only at the 20-sec. exposure duration. These results illustrate the disparity in the information-gathering capabilities between the visual and haptic systems.     

Smoking habits and changes in smoking habits as they relate to chronic conditions and respiratory symptoms

The relation of smoking to chronic lung disease has been documented in several studies. Several conclusions have been drawn about the type of smoking associated withdisease, including inhalation, filter tip use, and reduction in smoking. These factors were examined in a community epidemiologic study of chronic obstructive lung diseases. It was found that the community population exhibited greater filter tip use and higher rates of exsmoking than often seen elsewhere. Smoking habits and the changes in smoking habits over time were related to physician-diagnosed emphysema and/or chronic bronchitis, but not asthma. Some relation was seen also with present heart trouble. There was dose-relationship to pack-years of smoking in both present and ex-smokers. There were more ex-smokers among males. Most male ex-smokers quit due to symptoms. Ex-smokers were found to have high rates of diagnosed disease but reduced rates of symptoms. The incidence of diagnosed disease was found to be associated with smoking, both in intensity and duration. Changes in smoking over time were found to be correlated with symptomatology.     

Dystroglycan in development and disease

Our understanding of the structure and function of dystroglycan, a cell surface laminin/agrin receptor, has increased dramatically over the past two years. Structural studies, analysis of its binding partners, and targeted gene disruption have all contributed to the elucidation of the biological role of dystroglycan in development and disease. It is now apparent that dystroglycan plays a critical role in the pathogenesis of several muscular dystrophies and serves as a receptor for a human pathogen as well as being involved in early development, organ morphogenesis, and synaptogenesis.     

Experimental evaluation of two simple thermal models using transient temperature analysis

Thermal models are used to predict temperature distributions of heated tissues during thermal therapies. Recent interest in short duration high temperature therapeutic procedures necessitates the accurate modelling of transient temperature profiles in heated tissues. Blood flow plays an important role in tissue heat transfer and the resultant temperature distribution. This work examines the transient predictions of two simple mathematical models of heat transfer by blood flow (the bioheat transfer equation model and the effective thermal conductivity equation model) and compares their predictions to measured transient temperature data. Large differences between the two models are predicted in the tissue temperature distribution as a function of blood flow for a short heat pulse. In the experiments a hot water needle, approximately 30 degrees C above ambient, delivered a 20 s heating pulse to an excised fixed porcine kidney that was used as a flow model. Temperature profiles of a thermocouple that primarily traversed the kidney cortex were examined. Kidney locations with large vessels were avoided in the temperature profile analysis by examination of the vessel geometry using high resolution computed tomography angiography and the detection of the characteristic large vessel localized cooling or heating patterns in steady-state temperature profiles. It was found that for regions without large vessels, predictions of the Pennes bioheat transfer equation were in much better agreement with the experimental data when compared to predictions of the scalar effective thermal conductivity equation model. For example, at a location r approximately 2 mm away from the source, the measured delay time was 10.6 +/- 0.5 s compared to predictions of 9.4 s and 5.4 s of the BHTE and ETCE models, respectively. However, for the majority of measured locations, localized cooling and heating effects were detected close to large vessels when the kidney was perfused. Finally, it is shown that increasing flow in regions without large vessels minimally perturbs temperature profiles for short exposure times; regions with large vessels still have a significant effect.     

Proton T1rho-dispersion imaging of rodent brain at 1.9 T

Detection of H2(17)O with proton T1rho-dispersion imaging holds promise as a means of quantifying metabolism and blood flow with MRI. However, this technique requires a priori knowledge of the intrinsic T1rho dispersion of tissue. To investigate these properties, we implemented a T1rho imaging sequence on a 1.9-T Signa GE scanner. A series of T1rho images for different locking frequencies and locking durations were obtained from rat brain in vivo and compared with 5% (wt/vol) gelatin phantoms containing different concentrations of (17)O ranging from .037% (natural abundance) to 2.0 atom%. Results revealed that, although there is considerable T1rho-dispersion in phantoms doped with H2(17)O, the T1rho of rat brain undergoes minimal dispersion for spin-locking frequencies between .2 and 1.5 kHz. A small degree of T1rho dispersion is present below .2 kHz, which we postulate arises from natural-abundance H2(17)O. Moreover, the signal-to-noise ratios of T1rho-weighted images are significantly better than comparable T2-weighted images, allowing for improved visualization of tissue contrast. We have also demonstrated the feasibility of proton T1rho-dispersion imaging for detecting intravenous H2(17)O on a live mouse brain. The potential application of this technique to study brain perfusion is discussed.     

Evaluation of an extremely flatulent patient: case report and proposed diagnostic and therapeutic approach

We recently encountered a patient with severe flatulence who previously had been subjected to innumerable diagnostic tests and ineffective therapies based on the belief that his rectal gas was produced in the colon. Analysis of three flatus samples demonstrated that nitrogen (N2) was the predominant flatus gas whereas the three gases produced in the gut (CO2, H2 [hydrogen], and CH4 [methane]) comprised <16% of rectal gas. This result plus a series of other diagnostic tests clearly indicated that the patient's flatus was derived almost entirely from swallowed air. Based on this case, the present report summarizes available data on excessive flatulence and suggests a rational approach to the patient complaining of this problem. Particular emphasis is placed upon a sequential strategy consisting of: 1) a count of flatus passages to determine if the subject truly is abnormal (normal: <20 passages/day); 2) an analysis of flatus to determine if the flatus originates from swallowed air (predominantly nitrogen) or intraluminal production (predominantly CO2, H2, and CH4); and 3) treatment based upon the origin of the rectal gas.     

Report of the first case of invasive fungal sinusitis caused by Scopulariopsis acremonium: review of scopulariopsis infections

Scopulariopsis acremonium is a species of saprophytic fungus not previously reported to cause invasive disease in humans, although invasive infections from other species of Scopulariopsis have been reported and are reviewed. Deep infection with this fungus is associated with a high mortality rate. Invasive fungal sinusitis, in general, is a potentially fatal disease that typically affects immunocompromised patients, such as those receiving intensive chemotherapy or undergoing bone marrow transplantation. We report a case of invasive fungal sinusitis caused by Scopulariopsis acremonium in a patient with leukemia, who was successfully treated with amphotericin B, itraconazole, endoscopic sinus surgery, and granulocyte colony-stimulating factor.