Mass spectrometry: application in the exercise sciences

This paper outlines a computerized system for monitoring physiological functions during exercise, using a mass spectrometer for analyzing the concentration of the mixed expired air. Examples are provided illustrating the operation of this system in both research and clinical situations. The most remarkable aspect of the system is its versatility, coupled with its accuracy. While the applications reviewed in this paper are rather narrow, work has been initiated using the mass spectrometer to measure residual lung volumes by the oxygen dilution technique, cardiac output by the CO2 rebreathing technique, and total body density by the helium dilution technique. The application of the mass spectrometer into other areas most certainty will occur in the near future.     

Hematuria and sickle cell disorders

To examine the relationship between gross hematuria and sickle cell disorders, all patients admitted to Grady Memorial Hospital with the diagnosis of a sickle cell disorder during a 14-month period were reviewed. Of 115 such patients, 65% had sickle cell disease and 35% had sickle cell trait. None of the former but seven of the latter group had gross hematuria. Mean age of the seven was 30 years. Comprehensive examinations and laboratory studies showed that all were free of concomitant disease. Physical findings, diagnostic modalities, and treatment were reviewed. Findings suggest that conservative therapy (bed rest, hydration, and diuresis) is usually effective.     

Quantitative blood speed imaging with intravascular ultrasound

Previously, we presented a method of real-time arterial color flow imaging using an intravascular ultrasound (IVUS) imaging system, where real-time RF A-scans were processed with an FIR (finite-impulse response) filter bank to estimate relative blood speed. Although qualitative flow measurements are clinically valuable, realizing the full potential of blood flow imaging requires quantitative flow speed and volume measurements in real time. Unfortunately, the rate of RF echo-to-echo decorrelation is not directly related to scatterer speed in a side-looking IVUS system because the elevational extent of the imaging slice varies with range. Consequently, flow imaging methods using any type of decorrelation processing to estimate blood speed without accounting for spatial variation of the radiation pattern will have estimation errors that prohibit accurate comparison of speed estimates from different depths. The FIR filter bank approach measures the rate of change of the ultrasound signal by estimating the slow-time spectrum of RF echoes. A filter bank of M bandpass filters is applied in parallel to estimate M components of the slow-time DFT (discrete Fourier transform). The relationship between the slow-time spectrum, aperture diffraction pattern, and scatterer speed is derived for a simplified target. Because the ultimate goal of this work is to make quantitative speed measurements, we present a method to map slow time spectral characteristics to a quantitative estimate. Results of the speed estimator are shown for a simulated circumferential catheter array insonifying blood moving uniformly past the array (i.e., plug flow) and blood moving with a parabolic profile (i.e., laminar flow)     

Surgical management of locally recurrent rectal cancer

The surgical management of locally recurrent rectal cancer may involve major procedures and is not for the faint-hearted. Nevertheless, such treatment is preferable to chemotherapy and radiotherapy; the latter will fail over a period of months during which the patient is likely to experience intractable pain. Radical surgery offers good palliation and a better quality of life. Survival is prolonged by such operations which may be curative in up to one-third of patients. Nevertheless, surgeons must be realistic in their assessment of and discussions with patients.     

Pitfalls of processed pseudogenes in RT-PCR

The patient was a 72-year-old female who had Stage IVb advanced gastric cancer with Virchow's and paraaortic lymph node metastases. She was considered nonresectable and placed on neoadjuvant chemotherapy consisting of low-dose CDDP and 5-FU. After 1 course of administration, Virchow's metastasis disappeared, and the tumor was remarkably reduced in size. However, this chemotherapy was interrupted by toxicity of grade 3 appetite loss, nausea and vomiting, so that total gastrectomy and splenectomy were performed, which were non-curative operation because of paraaortic lymph node metastases. Histopathological examination of the section of the primary tumor revealed that cancer cells had almost disappeared, and only a few atypical cells remained in the granulation tissue. Eleven months after the surgery, there has been no progression of Virchow's and paraaortic lymph node metastases. Combination chemotherapy of low-dose CDDP and 5-FU appears useful as an inductive approach to advanced gastric cancer.