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Biomedical subjects

C Chou

Publications and source records attributed to C Chou.

At least 37 records · Page 2Linked to original sources
PubMed1995

99Tcm-MIBI mammoscintigraphy of breast masses: early and delayed imaging.

Forty patients with breast mass and 10 female controls underwent double-phase (15 min and 3 h) 99Tcm-sestamibi (MIBI) imaging. Another four post-mastectomy patients with suspected metastases underwent total body imaging at 15 min. The 99Tcm-MIBI images of all 10 female controls showed symmetrical homogeneous radioactivity in both breasts. A focal area of increased 99Tcm-MIBI uptake in the breast tumour is considered as positive. Eleven breasts of 10 patients underwent total mastectomies with lymph node dissection, with one patient having bilateral mastectomy. These 11 breast tumours were confirmed to be infiltrating ductal carcinoma. All 11 breast carcinomas had positive early and delayed phase results with the exception of one patient who had only a focal increased uptake in early phase which happened to be the smallest size of carcinoma. Focal areas of positive MIBI uptake in the axillae in 4 of 10 patients were confirmed to be metastatic carcinoma of the breast. One patient with breast carcinoma underwent mastectomy whose 99Tcm-MIBI imaging was negative. Twelve patients undergoing excisional biopsy or lumpectomy of breast resulted in 7 fibroadenomas, 2 papillomas, 1 abscess, 1 granuloma and 1 chronic inflammation. Four of 7 fibroadenomas having hypercellularity histopathologically exhibited a focal MIBI uptake on double-phase imaging. One granulomatous disease had positive early phase but faded on the delayed image. The patients with absence of MIBI uptake included 3 fibroadenomas, 2 papillomas, 1 abscess, 1 chronic inflammation and 17 fibrous hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Phase II study of 13-cis-retinoic acid and interferon-alpha 2a in patients with advanced squamous cell lung cancer.

The combination of interferon (IFN)-alpha 2a and 13-cis-retinoic acid (13-cRA) has demonstrated significant antitumor activity in patients with advanced squamous cell cancer of the skin and cervix. We performed a prospective phase II trial of this combination in patients with locally advanced or metastatic squamous cell lung cancer. Twenty-one patients were enrolled on the study. All patients were evaluable for toxicity and 17 were evaluable for response, four with locally advanced and 13 with metastatic disease. One partial response was obtained in a patient with locally advanced disease. Toxicity consisted mainly of constitutional side effects (fatigue, anorexia), which resulted in eight patients coming off-study. The combination of IFN-alpha 2a and 13-cRA is unlikely to exhibit significant clinical activity in patients with metastatic squamous cell lung cancer, but activity in patients with locally advanced disease has not been excluded.

Adult↗
PubMed1985

The uric acid-whewellite association in human kidney stones.

A total of twelve human kidney stones, composed almost exclusively of uric acid, whewellite and organic matrix were initially studied by x-ray (powder; single crystal), scanning and transmission electron diffraction techniques prior to as well as after exposure to 0.25 M EDTA solutions (96 hours; pH 7.1). Subsequent high-resolution scanning ion probe analyses eventually detected a phosphate phase not resolved by any of those techniques. Templates of organic matter lay above and in between the radial striations of whewellite. Often juxtaposing sets of striations are not in correct register with respect to one another. A sharp transition exists in the cores of the stones and separates an area characterized by the random deposition of whewellite from one in which the latter commences to grow in the form of radial striations. This transition is expected to be mediated by a physico-chemical and/or structural control. In laminae of organic matrix sectioned from EDTA-untreated cores well developed spherules are detected. Those superimpose on a substrate characterized by a considerable degree of crosslinking. Maximum spherule width is of the order of 0.8 micron. There is evidence of deposition in between the spherules. That deposition pattern appears to be controlled by the morphology and location of the spherules, thus suggesting that it is secondary to spherule formation.

Calcium Oxalate↗
PubMed1984

The uric acid-whewellite association in human kidney stones.

Human kidney stones, composed almost exclusively of uric acid and whewellite, were studied using x-ray (powder and single-crystal) as well as scanning electron-diffraction techniques. Whewellite--showing as a concentric aggregate characteristically marked by radial striations--is enclosed within a mass of uric acid, the crystallites of which grow with their b axis parallel to the radial direction of the striations. That axis corresponds to b (2 X 7.294 A) and tends to systematically superimpose over its uric acid counterpart (b = 7.40 A). Nonetheless no other such dimensional match was found for the other set of periodicities that characterize the uric acid whewellite interfaces, raising questions that a systematic epitaxial interaction could there take place. Selected uric acid-whewellite contacts and the crucial role of the "matrix" were also investigated.

Calcium Oxalate↗
PubMed1980

Morphogenesis of vaccinia virus in the process of envelopment as observed by freeze-etching electron microscopy.

The morphogenesis of vaccinia virus was studied during its synthesis in HeLa cells. Freeze-etching electron microscopy demonstrated intramembrane granules attached to convex faces, a granule-free area characterized by eccentric location and smooth appearance, and an eccentric nucleoid structure occasionally associated with a membranous structure. It is postulated that the granule-free area may be a precursor of the nucleoid envelope.

Crystallization↗
PubMed1978

Adriamycin cardiotoxicity: early detection by systolic time interval and possible prevention by coenzyme Q10.

Recent work suggests that adriamycin (ADM) cardiotoxicity results from the depletion of coenzyme 10 (CoQ10) activity in myocardial mitochondria. CoQ10 is indispensable in the bioenergetics of coupled respiration of oxidative phosphorylation. It exists naturally in mitochondria, especially in the myocardium. Bertazzoli et al have reported a decrease in ADM-induced cardiotoxicity by CoQ10 both in vivo and in the in vitro isolated rabbit heart. The systolic time interval (ATI) (pre-ejection period/left ventricular ejection time ratio) has been shown to increase (indicating cardiac dysfunction) with increasing doses of ADM. We have noted a gradual increase in the STI in eight of ten patients receiving 200-500 mg/m2 of ADM. Two of these eight patients had congestive heart failure (CHF) at doses of 200 and 350 mg/m2. The continued daily oral administration of 50 mg of CoQ10 beginning with the first dose of ADM resulted in a decreased incidence of cardiac dysfunction, and a gradual increase in STI occurred in only two of eight patients receiving 200-400 mg/m2 of ADM. CHF was observed inone patient at a dose of 350 mg/m2. It is suggested that CoQ10 was nontoxic and did not affect the antitumor activity or modify the ADM-induced bone marrow toxicity. A prospective randomized study comparing ADM with and without CoQ10 is in progress.

Aged↗
PubMed1977

Inhibition of thyroid-stimulating hormone stimulation of protein kinase, glucose oxidation, and phospholipid synthesis in thyroid slices previously exposed to the hormone.

Prior exposure of thyroid slices to thyrotropin (TSH) induced refractoriness to subsequent stimulation of the cyclic AMP system by the hormone. Although the inhibition is incomplete, we examined whether the reduction in cyclic AMP was sufficient to alter other metabolic effects of TSH. Bovine or dog thyroid slices were incubated with or without 5-100 mU/ml TSH for 1-2h, washed, and then incubated without hormone for 1-2h. Half of the slices not exposed to TSH initially were then incubated with buffer and half were exposed to 5-100 mU/ml TSH. Slices initially incubated with TSH were also incubated with or without TSH in the third incubation. During the refractory period, TSH activation of protein kinase was inhibited even though the hormone still caused some increase in cyclic AMP concentrations. However, protein kinase activity was fully responsive to dibutyryl cyclic AMP when slices were incubated with it during the third incubation. Stimulation of glucose oxidation by TSH was significantly decreased in thyroid slices previously incubated with the hormone. During refractoriness, stimulation of glucose oxidation caused by prostaglandin E1 and dibutyryl cyclic AMP was also significantly diminished but that due to acetylcholine was not. Thus even though dibutyryl cyclic AMP could fully activate protein kinase activity during refractoriness, its effect on glucose oxidation was still inhibited, suggesting that the metabolic block responsible for this refractoriness was distal to activation of protein kinase. Stimulation of 32Pi incorporation into phospholipid by TSH and acetylcholine was also inhibited during refractoriness. Despite reduction of the stimulatory effect of TSH, binding of 125ITSH was not modified by prior incubation of thyroid slices with TSH. These results indicate that changes in the TSH receptor are not responsible for the development of refractoriness and other metabolic sites besides activation of adenylate cyclase appear to be involved.

Acetylcholine↗
PubMed1975

Cochlear microphonics generated by microwave pulses.

Oscillations at 50 kHz have been recorded from the round window of guinea pigs during irradiation by 918-MHz pulsed microwaves. The oscillations promptly follow the stimulas, outlast it by about 200 musec and measure to 50 muV in amplitude. They precede the auditory nerve's response and disappear with death. They are interpreted to be a cochlear microphonic and hence to demonstrate that the microwave auditory effect, in the guinea pig at least, is accompanied by a mechanical disturbance of the hari cells of the cochlea.

Animals↗
PubMed1967

Daily rhythm in tyrosine concentration in human plasma: persistence on low-protein diets.

The concentration of tyrosine in the plasma of normal males varies diurnally. It is lowest (9.5 +/- 0.35 micrograms per milliliter) between 0130 and 0230 hours and rises to a peak of 16.2 +/- 0.82 micrograms per milliliter by 1030 hours. This rhythm persists when subjects are maintained for 2 weeks on a diet that is very low in protein.

17-Hydroxycorticosteroids↗