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Biomedical subjects

I W Chang

Publications and source records attributed to I W Chang.

5 recordsLinked to original sources
PubMed1998

Correlation of high-resolution magic angle spinning proton magnetic resonance spectroscopy with histopathology of intact human brain tumor specimens.

High-resolution magic angle spinning proton (HRMAS 1H) magnetic resonance spectroscopy produces well-resolved spectra of metabolites from intact tissue specimens. Here we report the results of a preliminary study of 19 human brain tumors obtained by applying this method. Among these 19 cases were 2 low-grade astrocytomas, 1 anaplastic astrocytoma, 8 glioblastomas, 6 meningiomas, and 2 schwannomas. In addition, autopsy human brain tissues from two subjects without any known neurological diseases were used as normal controls. The HRMAS 1H magnetic resonance spectroscopy measurements were performed at 2 degrees C on a 400-MHz NMR spectrometer with a HRMAS speed of 2.5 kHz. From these HRMAS 1H MR spectra, we measured the concentrations of 11 metabolites, the ratios of 15 metabolites (resonances) to creatine (at 3.03 ppm), and the spin-spin relaxation time for these metabolites (resonances). Our results indicate that these parameters have the potential to characterize tumor types and grades with statistical significance as well as identify tumor biochemical characteristics. In particular, we found that compared with metabolite concentrations and metabolite spin-spin relaxation time, the metabolic ratios presented the highest sensitivity in differentiating normal tissue from tumors, as well as in distinguishing between tumor groups. Of 15 analyzed metabolic ratios, 12 showed statistical significance in differentiating normal tissue from low-grade and anaplastic astrocytomas, 13 showed statistical significance in differentiating normal tissue from glioblastomas, 14 showed statistical significance in differentiating normal tissue from schwannomas, and 9 showed statistical significance in differentiating normal tissue from meningiomas. Moreover, our results strongly indicate that the resonance ratio of inositol (at 4.05 ppm) to creatine may help distinguish tumor type. Our results suggest that the HRMAS method for intact tissue measurement may function as an adjunct to histopathology and contribute to improved accuracy for brain tumor diagnoses.

Amino Acids↗
PubMed1998

Evaluating human breast ductal carcinomas with high-resolution magic-angle spinning proton magnetic resonance spectroscopy.

We report the results of a study of human breast ductal carcinomas, conducted by using high resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1HMRS). This recently developed spectroscopic technique can measure tissue metabolism from intact pathological specimens and identify tissue biochemical changes, which closely correspond to tumor in vivo state. This procedure objectively indicates diagnostic parameters, independent of the skill and experience of the investigator, and has the potential to reduce the sampling errors inherently associated with procedures of conventional histopathology. In this study, we measured 19 cases of female ductal carcinomas. Our results demonstrate that: (1) highly resolved spectra of intact specimens of human breast ductal carcinomas can be obtained; (2) carcinoma-free tissues and carcinomas are distinguishable by alterations in the intensities and the spin-spin relaxation time T2 of cellular metabolites; and (3) tumor metabolic markers, such as phosphocholine, lactate, and lipids, may correlate with the histopathological grade determined from evaluation of the adjacent specimen. Our results suggest that biochemical markers thus measured may function as a valuable adjunct to histopathology to improve the accuracy of and reduce the time frame required for the diagnosis of human breast cancer.

Adult↗
PubMed1978

The effects of 11-methyl 16,16 dimethyl prostaglandin E2 on canine gastric acid secretion.

11-Methyl 16,16 dimethyl Prostaglandin E2 (TM-PGE2) at peak effectiveness inhibited acid output stimulated submaximally by histamine in the dog by 95 and 84% when administered by the intravenous and oral routes, respectively. Inhibition of secretion was maintained for 1-1/2 hours following intravenous administration while with the oral route, secretory inhibition was still present at the end of two hours after administration of the drug. The degree of inhibition of acid secretion caused by TM-PGE2, its duration of action and the lack of side effects observed following administration of this drug makes it a suitable compound for evaluation as an anti-secretory agent in man.

Administration, Oral↗