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Biomedical subjects

C H Lu

Publications and source records attributed to C H Lu.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Experimental pathological study of brain damage in rats with copper deficiency].

Pathological observations on brain damage in baby rats with experimental copper deficiency were carried out and the following observations were made: 1. The cerebrum were decreased in size and weight, the cortex became thinner and the corpus striatum atrophic. 2. Vacuolar degeneration and swelling of the mitochondria in the extrapyramidal system within the corpus striatum resulted in axon damage and disintegration of the myelin sheath. 3. Proliferation of endoplasmic reticulum in the dark neurons, swelling and rupture of mitochondria in the light neurons, which can result in necrosis of both types of neurons. The damage due to copper deficiency could not be reversed by copper supplements in diet.

Animals↗
PubMed1994

Processing of an irrelevant location dimension as a function of the relevant stimulus dimension.

The effect of an irrelevant location dimension on choice reactions to the relevant stimulus dimension was examined. Experiment 1 used variations of the spatial Stroop task and the Simon task that differed in whether the relevant dimension (location name or color) was similar to the irrelevant location dimension. Congruity of the stimulus dimensions and stimulus-response (S-R) mapping had additive effects in the Simon task but overadditive effects in the Stroop task. Experiments 2-4 showed that each pattern could be obtained for both tasks, suggesting that dimensional similarity is not crucial; overadditivity occurred only when stimulus identification was prolonged. The results can be interpreted in terms of the relative timing of activation for the relevant and irrelevant information, if it is assumed that the activation function for irrelevant location varies across different stimulus-response mappings.

Adult↗
PubMed1993

Effects of different doses of norethisterone on ovarian function, serum sex hormone binding globulin and high density lipoprotein-cholesterol.

The ovarian effects of different doses of norethisterone (NET) were compared in 45 normally menstruating women in order to find the lowest effective dose of the Chinese NET "visiting pill". Subjects were randomly divided into 3 groups. Each subject in each group was taking 0.5, 1.5 or 3.0 mg per day from days 5 to day 18 of the cycle. Blood samples were taken on days 5, 8, 11, 14, 17, 20, 23, 26 and 29 of the cycle. Serum oestradiol (E2), progesterone (P), sex hormone binding globulin (SHBG), high density-lipoprotein cholesterol (HDL-C), and NET concentrations were measured. Ovulation, delayed ovulation, ovulation inhibition and follicular activity were classified by the analysis of the peripheral serum levels of sex hormones. Ovulation occurred in 7 women in the 0.5 mg group, in 2 women in the 1.5 mg group and in none of the 3.0 mg group. Mean serum SHBG levels were reduced progressively by 6.6% (Group 0.5), 15.5% (Group 1.5) and 23.4% (Group 3.0). There were no significant changes in HDL-C levels in any group. There was a significant correlation of mean serum NET concentrations with dose. The lack of complete inhibition of ovulation in most women in the 1.5 mg and 0.5 mg groups might suggest that the dose of NET required when used as a visiting pill could not be reduced below 3.0 mg.

Adult↗
PubMed1993

Stimulus-response compatability for moving stimuli: perception of affordances or directional coding?

Michaels reported a compatibility effect in which responses were fastest at the destination of a moving stimulus; she interpreted this "destination" compatibility effect in terms of catching actions "afforded" by the stimulus motion. The present study evaluated implications of the catching-affordance account and compared them with those of an account based on spatial coding of relative direction. The destination compatibility effect was obtained when the responses were keypresses rather that catching movements of a joystick and regardless of whether the stimulus expanded, contracted, or only changed location. This effect was a function of relative rather than absolute location of the responses. A similar compatibility effect was obtained when destinations were designated by static arrow stimuli. The results are inconsistent with the catching-affordance account and are best explained by the coding of relative direction.

Adult↗
PubMed1992

Enhancement of the Simon effect by response precuing.

When stimuli are presented to the left or right of fixation, and stimulus location is irrelevant, responses are faster if the stimulus location coincides with the location of the assigned response. This phenomenon is called the Simon effect. The present study examined the influence on the Simon effect of attentional precues that signaled the likely stimulus location and intentional precues that signaled the likely response. Experiment 1 was a close procedural replication of an experiment by Verfaellie, Bowers, and Heilman (1988); consistent with their findings, the Simon effect was enhanced by the intentional precue and unaffected by the attentional precue. Experiments 2 and 3 demonstrated the importance of the intentional precue with simpler procedures that involved only intentional and attentional precues, respectively. Finally, the intentional precuing enhancement of the Simon effect was obtained when two stimuli were assigned to each response, regardless of whether the hands were uncrossed (experiment 4) or crossed (experiment 5). Overall, the results indicate that response precuing enhances the Simon effect and favor response-selection accounts over those that attribute the effect to stimulus identification.

Adult↗
PubMed1991

[A light and electron-microscopic study of epileptogenic discharge focus in temporal lobe epilepsy].

Study of the structure of epileptogenic discharge focus in 16 cases of cryptic temporal lobe epilepsy was carried out through light and electron-microscopy. Microvascular malformation in both meninges and parenchyma of the brain were found in 9 cases. Ultrastructurally, all the 16 cases showed presence of tortuous capillaries in various extent accompanied with uneven thickening and splitting of the basement membrane, and 11 of them presented proliferation of the collagen fibers. Changes obtained in neurons were similar to those of the delayed neuronal death during ischemic damages of the brain tissue. Degeneration and edema of astrocyte processes were also available. These suggest that the local circulatory disturbance as a result of microvascular malformations may damage the inhibitory neurons of the hippocampus and amygdala and lead to the development of epileptic seizure.

Adolescent↗
PubMed1990

Sigmoid colon fistula complicating ovarian cystadenocarcinoma: a rare finding.

A case of sigmoid colon fistula complicating ovarian cystadenocarcinoma is reported. The entity demonstrated a large air-filled, thin-walled cystic lesion during barium enema examination. The differential diagnosis of distended air-filled cystic lesions is discussed and expanded to include colonic fistula complicating ovarian neoplasms.

Barium Sulfate↗
PubMed1990

Satisfaction of search in diagnostic radiology.

A subset of underreading errors (false-negative responses) in radiology has been attributed to "satisfaction of search," which occurs when lesions remain undetected after detection of an initial lesion. This phenomenon has not been studied in the experimental laboratory. A primary goal of this study was to develop a procedure or paradigm to study satisfaction of search. The authors measured detection accuracy for native lesions in images before and after the addition of a simulated nodular lesion. Simulated and native lesions were not spatially superimposed and the native abnormalities were physically identical with and without the nodules. Only responses related to the native lesion were analyzed. Accuracy parameters of receiver operating characteristic (ROC) curves were estimated by the method of maximum likelihood and jackknife. The average perceptual accuracy of the individual ROC curves as measured by Az and de' was significantly reduced with addition of the nodules (t = 2.364, p = 0.025, t = 2.648, p = 0.017, respectively). Az and de' parameters of the pooled ROC curve showed a similar effect (t = 1.573, p = 0.080; t = 1.934, p = 0.047, respectively). The results indicated a substantial satisfaction-of-search effect, with diminished accuracy in perception of native lesions.

Adolescent↗
PubMed1989

Primary adenocarcinoma of the duodenal bulb: radiographic and pathologic findings in two cases.

We reviewed the radiographic and pathologic findings in 2 patients with primary adenocarcinoma of the duodenal bulb. Barium studies provided important information, characterizing the nature and extent of the lesion, as well as complete evaluation of the descending and horizontal segments of the duodenum before surgical therapy. Early endoscopy is recommended for nonhealing duodenal ulcers, especially if suggestive malignant changes are present.

Adenocarcinoma↗
PubMed1989

Genotoxicity and genotoxic enhancing effect of tetrandrine in Salmonella typhimurium.

Tetrandrine has been used for the treatment of silicosis in China. The potential genotoxic and carcinogenic hazards of this drug were studied using the Salmonella/histidine reversion assay and the SOS/Umu test. The results show that tetrandrine was weakly mutagenic to Salmonella typhimurium TA98 with metabolic activation and did not induce SOS response. However, tetrandrine increased the mutagenic activity of benzo[alpha]pyrene, trinitrofluorenone (TNF), 2-aminoanthracene (2AA), diesel emission particles, airborne particles, and cigarette smoke condensate by more than 100%; the activity of aflatoxin B1 and fried beef was increased by over 75%. It also increased the 2AA and TNF-induced SOS response by more than 300%. These results indicated that tetrandrine was a weak promutagen inducing frameshift mutations and was a potent genotoxic enhancer. The mechanism for the genotoxic enhancement is not known. However, the fact that the increase in mutagenicity was noted only in TA98 and not in TA1538 suggested that the enhancement of genotoxicity by tetrandrine may result from an increase in error-prone DNA repair.

Alkaloids↗
PubMed1989

[Ferric ammonium citrate as virulence-enhancing agent in the toxicity test of Vibrio cholerae and the potency assay of cholera vaccine].

Using ICR strain mice as experimental animals, 0.25% (w/v) ferric ammonium citrate (FAC) was a suitable substitute for 5% (w/v) mucin as a virulence-enhancing (VE) agent in the toxicity test of Vibrio cholerae and the potency assay of cholera vaccine. There was no significant lethal toxicity difference between 0.25% FAC and 5% mucin as VE agents on Vibrio cholerae in mice. By using 0.25% FAC as a VE agent in estimating the potency of cholera vaccine, the relative potency (R.P.) of the tested cholera vaccine (Inaba) to the reference cholera vaccine (Inaba) was 0.896 +/- 0.208, the variation coefficient (V.C.) was 0.232, the correlation between the immune dose and the ratio of mouse death (r2) was 0.9932; for the cholera vaccine (Ogawa), R.P. was 1.373 +/- 0.366, V.C. was 0.266 and r2 was 0.8231. There was no significant difference between 5% mucin and 0.25% FAC used as VE agents in potency assay of cholera vaccine.

Animals↗
PubMed1988

Dendritic ramifications of trigeminal motor neurons innervating jaw-closing muscles of rats.

A cholera toxin subunit conjugated horseradish peroxidase (CTHRP) was found to be very useful in labelling the dendrites of motoneurons. CTHRP was injected individually to jaw-closing muscles (temporalis, masseter, and medial pterygoid) of rats, and their motoneurons including the dendrites were labelled and studied. The results show that the motoneuron cell bodies innervating temporalis, masseter, and medial pterygoid muscles are located in the trigeminal motor nucleus in dorsal, ventromedial and ventrolateral position. The dendrites of these motoneurons extend radially into mesencephalic nucleus, supratrigeminal nucleus, pontine reticular formation, trigeminal sensory nucleus and even into the bundles of the ascending root of the facial nerve. These dendrites may serve as an extended surface for various synaptic contacts to the jaw closing motoneurons. The possibility that they may also have presynaptic influence on the input to the trigeminal motoneurons is also discussed.

Animals↗
PubMed1987

Characterization of the binding of and the immune response to pneumococcal group 9 capsular polysaccharides.

The binding of Streptococcus pneumoniae 14C-9N and 14C-9V polysaccharides (PSs) to lymphocytes and polymorphonuclear leukocytes of human blood were studied. The quantity of 14C-9N and 14C-9V PSs bound to leukocytes was proportional to the number of leukocytes and the incubation time; the binding was temperature-dependent. The binding activity appeared to be specific, since the binding was inhibited by prior treatment with homologous group 9 PSs. The binding was also inhibited by prior treatment with cross-reactive group 9 PSs. The binding of 14C-9V PS to leukocytes was greater than that of 14C-9N PS. Reciprocal plot analysis revealed 6.4 X 10(4) binding sites for 9N PS on each lymphocyte and 9.5 X 10(4) binding sites for 9V PS on each lymphocyte, while the affinity constant for 9N PS was 3.7 X 10(9) M-1 and that for 9V PS was 9.4 X 10(8) M-1. Furthermore, there were 7.8 X 10(4) binding sites for 9N PS on each polymorphonuclear leukocyte and 1.2 X 10(5) binding sites for 9 V PS on each polymorphonuclear leukocyte, while the affinity constant for 9N PS was 1.6 X 10(9) M-1 and that for 9V PS was 8.5 X 10(8) M-1. There was a high degree of inhibition of the binding of 14C-9N PS to leukocytes by prior treatment with 9V PS, and a low degree of inhibition of the binding of 14C-9V PS to leukocytes by prior treatment with 9N PS. The high degree of inhibition of binding of 9V PS to leukocytes was not directly related to the production of cross-reactive antibodies to 9N PS. The serum antibody and the plaque-forming cell responses in mice immunized with 9V PS were significantly greater than responses in mice immunized with 9N PS.

Animals↗