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Biomedical subjects

W Y Lin

Publications and source records attributed to W Y Lin.

At least 127 records · Page 7Linked to original sources
PubMed1995

The change in the distribution of Tc-99m human serum albumin radioaerosols in asthma after a 1-week course of corticosteroid inhalation treatment.

This study evaluated the effects of corticosteroid inhalation on the deposition pattern of Tc-99m HSA radioaerosols in 24 patients with asthma. The homogeneous degree of depositing radioaerosol was quantitatively evaluated using a modified standard score system over both lungs. The baseline scores were calculated before inhalation therapy of 0.05 mg beclomethasone dipropionate four times daily for 1 week. The studies were then repeated after treatment to evaluate the effects of inhalation therapy. After treatment, the scores decreased in 16 of 24 cases (67%), which means that the degree of the bronchial obstruction decreased. The statistical results revealed significant differences in the total homogeneity score (P < 0.001) before and after therapy. Thus, a 1-week course of beclomethasone dipropionate inhalation therapy improves the bronchial obstruction in asthma patients as shown by the quantitative homogeneity score system of the Tc-99m HSA radioaerosol inhalation lung scintigraphy.

Administration, Inhalation↗
PubMed1995

Three-phase abdominal scintigraphy in lupus vasculitis of the gastrointestinal tract.

Gastrointestinal vasculitis is a recognized but frequently misdiagnosed complication of systemic lupus erythematosus. The authors investigated the usefulness of three-phase Tc-99m pyrophosphate abdominal scintigraphy for identifying areas of vasculitis in patients with systemic lupus erythematosus who have gastrointestinal symptoms (diarrhea or abdominal pain). Among patients with gastrointestinal symptoms, 62 of 82 (75%) patients showed positive scan results, suggesting gastrointestinal vasculitis. Among patients without gastrointestinal symptoms, 6 of 43 (13%) patients showed positive scan results. Although three-phase Tc-99m pyrophosphate abdominal scintigraphy cannot provide a definite diagnosis of vasculitis of the gastrointestinal tract, it is a noninvasive and convenient method for suggesting and monitoring gastrointestinal vasculitis.

Abdomen↗
PubMed1995

Comparison of TI-201 and Tc-99m MIBI SPECT imaging in nasopharyngeal carcinoma.

Both TI-201 and Tc-99m MIBI uptake in nasopharyngeal carcinoma (NPC) have been reported, yet no comparative study of these two agents using SPECT images has been undertaken for NPC. This study compares the relative effectiveness of TI-201 and Tc-99m MIBI SPECT for detecting NPC. In the patients with NPC, 26 of 32 (81%) showed TI-201 tumor uptake, whereas 24 of 32 (75%) showed Tc-99m MIBI tumor uptake. This preliminary study suggests that both Tc-99m MIBI and TI-201 SPECT imaging can be helpful in detecting NPC, and that sensitivity is slightly higher in TI-201 SPECT imaging.

Adult↗
PubMed1995

Skull morphology affected by different sleep positions in infancy.

In infancy, prior to cranial suture and fontanel calcification, the craniofacial skeleton can be easily deformed by an externally exerted force. In this study, the relationship between the sleep position and skull morphology was investigated. A group of 81 cleft lip and/or palate infants without other systemic anomalies was first seen in the craniofacial center at approximately 1 month of age. The sleep position of each infant was recorded as supine, prone, or mixed type. The body and skull growth were longitudinally measured at 1, 3, and 6 months of age. Infants sleeping in the supine sleep position tended to have a wider head width, shorter head length, and a larger cephalic index by 6 months of age. The opposite phenomena were observed in the prone sleep group. The mixed sleep group tended to have head width, head length, and cephalic index between those of the supine sleep group and the prone sleep group. During the first 3 months of life, the sleep position could mold the skull primarily in the dimension of head width. In conclusion, the supine sleep position may promote brachycephaly and the prone sleep position dolichocephaly.

Age Factors↗
PubMed1995

Bone scintigraphy in evaluation of heel pain in Reiter's disease: compared with radiography and clinical examination.

Tc-99m MDP bone scans were used to evaluate the heel pain (talalgia) in 38 patients with Reiter's disease, and compared with clinical examination and radiologic findings. In our work, 58% (22/38) patients presented talalgia with a total of 35 lesions. Only two lesions of clinical talalgia were missed by the bone scan. The diagnostic sensitivity was as high as 94% (33/35). However, the diagnostic sensitivity of radiography was only 69% (11/16) when the disease duration was more than one year; furthermore, it declined to 33% (4/12) when the disease duration was less than one year. Based on the bone scans, the correlation between positive scintigraphic findings and clinical talalgia was extremely good. Clinical talalgia occurred in all the 33 lesions demonstrated by bone scan. However, three lesions demonstrated by radiography were not consistent with clinical talalgia and not visualized by radioscintigraphy. Our data show that the radionuclide scan is a more sensitive indicator and has better correlation with clinical talalgia than radiography. We consider that bone scintigraphy is superior to radiography in the evaluation of heel pain in Reiter's disease.

Adolescent↗
PubMed1995

Hepatic perfusion index in evaluating treatment effect of transcatheter hepatic artery embolization in patients with hepatocellular carcinoma.

We assumed the hepatic perfusion index (HPI) in patients with hepatocellular carcinoma (HCC) treated by transcatheter arterial embolization (TAE) and compared the results with the following CT findings. From September 1993 to February 1994, 15 patients with newly diagnosed HCC, proven by biopsy, were studied. Hepatic perfusion index (HPI) studies were performed before-TAE as well as on the 1st day and 7th day post-TAE, and CT scans were performed before and one month after the TAE. HPI at 1st-day post-TAE (HPI1) over HPI pre-TAE (HPIp) and HPI at 7th-day post-TAE (HPI7) over HPIp were calculated. The HPI7/HPIps were chosen to evaluate the efficacy of TAE because they had better correlation with the CT findings than HPI1/HPIps. CT scans performed one month after the TAE showed obvious reduction of tumor size in all 7 patients with a HPI7/HPI p < 0.85 but in only 2 of the 7 patients with a HPI7/HPI p > or = 0.85. The difference was significant, with a p-value of 0.01 by Fisher's exact test. We consider that the HPI with its characteristics of relative safety, convenience, low radiation exposure, and inexpense, may provide an useful modality for early prediction of the efficacy of hepatic artery embolization in the treatment of HCC.

Aged↗
PubMed1995

The role of Hispanic race/ethnicity and poverty in breast cancer survival.

The association of Hispanic race/ethnicity and poverty with general survival time and breast cancer survival time was examined for a total of 14,896 breast cancer patients (14,035 White and 861 Hispanic) included in the National Cancer Institute Surveillance Epidemiology and End Results (NCI SEER) program in New Mexico and San Francisco between 1975 and 1984. Variables examined included: age, marital status, stage at diagnosis, tumor histology, delay, treatment, period of diagnosis (1975-79 vs. 1980-84), and poverty. Univariate analysis of 14,896 patients indicated that a greater proportion of Hispanics (vs. Whites) with breast cancer were: younger than age 50, married, diagnosed at a later stage, diagnosed in New Mexico, lived in greater poverty, were diagnosed between 1980-84, and died from breast cancer. Univariate Cox Proportion Hazards analysis indicated that poverty was a significant predictor for reduced general survival time. Being diagnosed in the 1980-84 period was a predictor for improved general survival time. Poverty and Hispanic race/ethnicity were significant predictors of reduced breast cancer survival time. Multivariate Cox Proportional Hazards models indicated that Hispanic race/ethnicity was a significant risk factor for breast cancer survival time for women aged 50 and older. For White women: state, marital status, poverty, surgery, radiation/hormonal treatments, and histology were significant risk factors for breast cancer survival time. For Hispanic women: stage, surgery, hormonal treatment and period of diagnosis were significant risk factors for breast cancer survival time. For White breast cancer patients, period of diagnosis was not a significant risk factor for reduced breast cancer survival time; but for Hispanics, it was a significant risk factor. In the age and race/ethnicity-stratified models of breast cancer survival time, similar risk factors emerged for both Whites and Hispanics. For both younger and older Hispanics, being diagnosed in the early 1980's (vs. the late 1970's) was associated with reduced breast cancer survival time--vs. Whites, who experienced no significant change in breast cancer survival time in the same time period. Poverty was not a predictor for Hispanic survival time in any of the models; however, it was a predictor for younger Whites for breast cancer survival time. These results fueled discussion in three areas targeting breast cancer in underserved women: the development of racial/ethnic-specific cancer control guidelines, the development of a breast cancer integrated delivery system, and population management.

Adult↗
PubMed1995

Lung toxicity of chemotherapeutic agents detected by TC-99m DTPA radioaerosol inhalation lung scintigraphy.

We investigated the lung toxicity of chemotherapeutic drugs in patients with breast cancer by means of Tc-99m DTPA aerosol scintigraphy. Thirty three patients who underwent surgical resection for breast cancer were divided into two groups, those who received a combination of adjuvant chemotherapy and those who did not. Group 1 consisted of 19 patients who received adjuvant chemotherapy and group 2 consisted of 14 patients who did not received adjuvant chemotherapy. Chemotherapeutic agents included 5-fluorouracil 1000 mg, endoxan 1000 mg and MTX 50 mg, all given intravenously. Aerosol lung scintigraphy was performed in all patients, in the supine position. The degree of lung damage was presented as the half clearance time (T 1/2) in minutes from the dynamic lung images. Only the right lung was used to analyze clearance, in order to avoid interference from stomach activity on the left side. The results show T 1/2 times of 68.18 +/- 20.04 min and 94.46 +/- 34.78 min, over the right lung, for groups 1 and 2, respectively. The difference is significant, with a p-value of 0.016, using the Mann-Whitney U test. We conclude that some chemotherapeutic drugs such as MTX, may result in pulmonary damage and that aerosol lung scintigraphy can provide an objective mean for early detection of pulmonary damage during cytotoxic chemotherapy.

Administration, Inhalation↗
PubMed1995

Tc-99m DTPA aerosol lung clearance test in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) can affect every organ. Involvement of the lung in systemic lupus erythematosus may be a significant cause of morbidity and mortality. To evaluate alveolar epithelial damage in SLE, we studied lung epithelial permeability by measuring the clearance of inhaled Tc-99m DTPA aerosol. Twenty-three SLE patients without clinical pulmonary manifestations were studied. Of the 23 patients, 16 had normal clearance rates of Tc-99m DTPA (T1/2 > 60mins) and normal chest X-ray findings. A mild increase in the clearance rate was found in 5 cases (T1/2 between 40-60 min) and a significant increase in clearance rate in the remaining 2 (T1/2 < 40mins). Totally, 30% (7/23) of SLE patients have abnormal lung permeability. Of the 7 patients with abnormal clearance of Tc-99m DTPA, 3 had abnormal findings in chest X-rays and four had normal chest X-rays. Our study suggests that the clearance of Tc-99m DTPA aerosol may be a useful complementary study to assess pulmonary involvement in SLE.

Adolescent↗
PubMed1995

Technetium-99m-pyrophosphate scintigraphic findings of intestinal perforation in dermatomyositis.

Gastrointestinal complications are more common in children than in adults and present a serious problem with dermatomyositis. We report on a 66-yr-old man with dermatomyositis who suffered from intestinal perforation. The abdominal plain radiograph revealed only dilatation of the intestinal loops; increased radioactivity, however, was clearly demonstrated in the early 5-min and delayed 3-hr 99mTc-pyrophosphate images.

Aged↗
PubMed1995

The normal values of the radionuclide esophageal transit test and the influence of age and gender in healthy Chinese.

This study evaluates esophageal function in 55 healthy Chinese using a radionuclide esophageal transit test (RETT) of solid and liquid foods. A standard method modified from Klein et al. and Russell et al. was used to calculate: total mean transit time (MTT), residual fraction (RF), and retrograde index (RI) in the supine position. In Group 1, 30 cases accepted solid food RETT and in Group 2, 25 cases accepted liquid food RETT. Both groups were divided into different subgroups based on their ages: older and younger or according to their sex: male and female. The results show significant differences in MTT, RF and RI between the two groups, but no statistical differences were found in all of the parameters between the subgroups based on age or sex in both food types. In conclusion, the RETT is a simple and non-invasive method of evaluating the esophageal functions for both types of food and influences due to differences in age or sex were not significant in healthy Chinese.

Adult↗
PubMed1994

Chemical modification of aminopeptidase isolated from Pronase.

Chemical modification of aminopeptidase from pronase has revealed two important histidines in enzyme catalysis. In the absence of metal ions, modification of the readily-modified histidine (pKa 6.9 +/- 0.5) results in a drastic loss of activity, indicating that this residue is indispensible for enzyme activity. In the presence of CaCl2, the modified enzyme still retains approx. 60% of the activity, whereas modification of another histidine (pKa 7.7 +/- 0.2) leads to a dramatic loss of activity. In fact, the enzyme with the first histidine being modified is active only in the presence of metal ions. Moreover, modification of the second histidine is prevented by the presence of Ca(II). These results indicate that the second histidine is serving as a ligand for Ca(II) and the bound Ca(II) is directly involved in enzyme catalysis. The c.d. spectra of the modified and unmodified enzymes in the absence or presence of CaCl2 are all very similar, indicating that no gross conformational changes in protein occur upon modification or by the presence of Ca(II). Modification of both histidines is prevented by the presence of a competitive inhibitor, suggesting that they are located in the active centre. Modification of 11 amino groups, two tyrosines, or four arginines causes no appreciable inactivation of the enzyme, indicating that these residues are not directly involved in enzyme catalysis.

Aminopeptidases↗
PubMed1994

Detection of gaps in sinusoids by frog auditory nerve fibers: importance in AM coding.

Physiological studies were carried out in the frog (Rana pipiens pipiens) eighth nerve to determine: (i) whether the modulation rate or the silent gap was the salient feature that set the upper limit of time-locking to pulsed amplitude-modulated (PAM) stimuli, (ii) the gap detection capacity of individual eighth nerve fibers. Time-locked responses of 79 eighth nerve fibers to PAM stimuli (at the fiber's characteristic frequency) showed that the synchronization coefficient was a low-pass function of the modulation rate. In response to PAM stimuli having different pulse durations, a fiber gave rise to non-overlapping modulation transfer functions. The upper cut-off frequency of time locking was higher when tone-pulses in PAM stimuli had shorter duration. The fact that the cut-off frequency was different for the different PAM series suggested that the AM rate was neither the sole, nor the main, determinant for the decay in time-locking at high AM rates. Gap detection capacity was determined for 69 eighth nerve fibers by assessing fiber's spiking activities to paired tone-pulses during an OFF-window and an ON-window. It was found that the minimum detectable gap of eighth nerve fibers ranged from 0.5 to 10 ms with an average of 1.23-2.16 ms depending on the duration of paired tone pulses. For each fiber, the minimum detectable gap was longer when the duration of tone pulses comprising the twin-pulse stimuli was more than four times longer. When the synchronization coefficient was plotted against the silent gap between tones pulses in the PAM stimuli, the gap response functions of a fiber as derived from multiple PAM series were equivalent to gap response functions deriving from twin-pulse series suggesting that it was the silent gap which primarily determined the upper limit of time-locking to PAM stimuli.

Acoustic Stimulation↗
PubMed1994

Dysphagia in Parkinson's disease. Assessment by solid phase radionuclide scintigraphy.

Patients with Parkinson's disease often experience dysphagia, in which case food seems to be blocked in the throat. The patient must swallow over and over to get it down. A radionuclide solid phase esophageal motility study was conducted to evaluate esophageal function of patients with Parkinson's disease. Twenty-seven patients and 27 age-matched normal volunteers were studied. Each subject was placed in the supine position above a gamma camera linked to a computer and was given a 4 mL bolus of solid gelatin containing 75 MBq Tc-99m pertechnetate. Data were acquired in the list mode. A computer routine was used to calculate the total mean transit time, the residual fraction after the first swallow, and the retrograde index. The preliminary results suggest: 1) patients with Parkinson's disease display significantly slowed transit time when compared with normal age-matched controls, and 2) dysphagia of Parkinson's disease may improve with medication. A solid phase esophageal motility study may be used as a monitor of dysphagia in patients with Parkinson's disease in our future studies.

Aged↗
PubMed1994

The role of Tc-99m MDP and Ga-67 imaging in the clinical evaluation of malignant fibrous histiocytoma.

The purpose of this study was to evaluate the value of bone and Ga-67 imaging in patients with malignant fibrous histiocytoma (MFH). Thirty-four patients with biopsy-proven MFH were studied. Of these patients, 15 underwent Ga-67 imaging, 26 underwent Tc-99m MDP imaging, and 7 underwent both imaging procedures. In evaluation of the primary tumors, intense Ga-67 uptake was observed in 14 of 15 patients with a diagnostic sensitivity of 93.3%. However, positive bone imaging results were observed in only 10 of 26 patients with a diagnostic sensitivity of 38.5%. Most of these were secondary to Tc-99m MDP uptake in adjacent bone invaded by the primary tumor. Only two patients, of the 18 patients without direct bone invasion, had increased radioactivity in the tumors (11.1%). In evaluation of the metastatic lesions, increased Ga-67 uptake was observed in 8 of 8 metastatic sites (100%). However, Tc-99m MDP could only detect 5 of 12 metastatic sites (41.7%), which were all diagnosed to be bone metastases. None of the extraskeletal metastasis could be detected by Tc-99m MDP imaging. Ga-67 scintigraphy appears to be a very useful tool in the evaluation of both primary and metastatic lesions of MFH and is assumed to be useful in the follow-up. However, it is emphasized that bone scintigraphy is useful only when the tumor invades the skeletal system and is of limited value in the evaluation of extraskeletal lesions.

Bone Neoplasms↗
PubMed1994

Phase-locked response characteristics of single neurons in the frog "cochlear nucleus" to steady-state and sinusoidal-amplitude-modulated tones.

1. We made extracellular recordings from 164 single neurons in the frog dorsal medullary nucleus (DMN), a homologue of the cochlear nucleus. Phase-locked responses to tones at the unit's characteristic frequency (CF) and to off-CF tones were evaluated. We also stimulated units with tones at CF that were amplitude modulated sinusoidally between 5 and 1,000 Hz and examined responses to these stimuli. 2. Results showed that single neurons in the frog DMN displayed phase-locked discharges to tones at frequencies < or = 800 Hz. Phase-locking was robust at low frequencies (< 400 Hz) and became poorer at higher frequencies; the variation of the synchronization coefficient (SC) with frequency typically showed a low-pass characteristic. 3. The capacity of phase-locking to tones was correlated with the functional classification of a DMN neuron and the firing rate of its CF response. Primarylike neurons exhibited various degrees of phase-locked discharges to tones at off-CF frequencies. The average upper cutoff frequency, i.e., the frequency at which the SC dropped to 0.5 of maximum value, differed for the three classes of primarylike neurons. The average cutoff frequency was respectively 183, 325, and 536 Hz for primarylike neurons that displayed low (PL-1), intermediate (PL-2), and high (PL-3) steady-state firing rates to CF stimulation. The phasic neurons showed poor phase-locking capacities at all tone frequencies. 4. The frequency range of phase-locking to amplitude-modulated stimuli was also different for the different cell types, as evidenced by the units' modulation transfer functions (MTFs). The primarylike neurons exhibited mostly all-pass or low-pass sync-based MTFs. The mean upper cutoff frequencies for primarylike neurons having low-pass MTFs were 155 Hz for PL-1 neurons, 176 Hz for PL-2 neurons, and 218 Hz for PL-3 neurons. Pauser, chopper, phasic, and phasic-burst neurons gave mostly low-pass MTFs having a mean upper cutoff frequency of 219, 235, 242, and 251 Hz, respectively. 5. The phase-locking ability of DMN neurons to tones and to amplitude-modulated stimuli are compared with those of frog's primary afferent fibers and with those of avian and mammalian cochlear nucleus neurons. The significance of results in terms of sound localization and sound pattern recognition is discussed.

Animals↗
PubMed1994

Maternal and child health in urban Sabah, Malaysia: a comparison of citizens and migrants.

This paper describes selected maternal and child health indicators based on a cross-sectional study of citizens and migrants in Sabah, Malaysia. A total of 1,515 women were interviewed from a multi-stage random sample of households in eight urban centers. Among the 1,411 women in the sample who had experienced a pregnancy before, 76% were local citizens and 24% were migrants. There were statistically significant differences between citizens and migrants in ethnicity, religion, education, household income, and access to treated water supply and sanitary toilet facilities. Significantly fewer migrants practiced any form of contraception and obtained any antenatal care during any pregnancy. Furthermore, citizens tended to initiate care as early as three months but migrants as late as seven months. Despite these differences, only the infant mortality rate, and not pregnancy wastage, was statistically significantly higher among migrants. Pregnancy interval was also similar between the two groups. The influence of several socioeconomic factors on pregnancy wastage and infant mortality was explored.

Adolescent↗