Biomedical subjects
Publications and source records attributed to W Y Cheng.
Particulate and histopathologic examination of atherosclerotic material collected during carotid artery stenting is presented, illustrating the limitations of current knowledge regarding the use of distal protection devices (DPD) during this novel vascular intervention.
Primary brain tumors associated with intracranial aneurysm are rare. A combination of glioblastoma multiforme (GBM) with cerebral aneurysm is even more rare. We present a 67-year-old female, who suffered from progressive weakness of the right limbs and dysphasia for 2 days. She was referred from another hospital with impression of having a brain tumor. The non-enhanced computed tomographic (CT) scan of the brain showed a mass lesion over the left parietal region, and another tiny lesion with relatively high density over the left suprasellar region. After admission, the carotid angiogram revealed a 13 x 12 x 14 mm aneurysm with a base about 8 mm from the anterior wall of the left supraclinoid internal carotid artery (ICA) between the left ophthalmic artery and the left anterior choroid artery. We first clipped the aneurysm by a basal pterion keyhole approach. One week later, the tumor was en bloc removed by a small left parietal craniotomy under the guidance of a navigator. The final diagnosis was confirmed by histopathological examination as GBM. After the surgeries, the patient received palliative radiotherapy with a dose of 4000 cGy. She recovered well with no evidence of recurrence of the tumor one year after the operations. In this report, the careful diagnosis and the possible mechanisms of concurring GBM and cerebral aneurysm, as well as the strategies of surgical treatment involving minimally invasive approaches are discussed.
Being the most common childhood tumor to involve the hypothalamus and pituitary gland, craniopharyngioma, a histologically benign tumor, is usually related to growth retardation and hypogonadism. The presentation of precocious puberty is very rare for a hypothalamic craniopharyngioma. Here, we report such a case. The female patient had presented with symptoms of menarche and breast development since she was 6 years old. Hormonal therapy with a gonadotropin-releasing hormone analogue was instituted to cease precocious puberty but was unsuccessful. Magnetic resonance imaging of the sella showed a 1-cm tumor in the hypothalamic area. Through a pterional approach, the tumor was removed en bloc with endoscope-assisted microsurgery. After the operation, our patient's symptoms improved, so the hormone therapy was discontinued. This extremely unique association of craniopharyngioma and precocious puberty, the causes and mechanisms involved along with the advantages of endoscope-assisted microsurgery are discussed.
OBJECTIVE: To evaluate positron emission tomography (PET) in diagnosing and staging of lung cancer. METHODS: One hundred and forty-seven patients (93 with lung cancer, 15 with lung metastatic tumors, 39 with benign lesions) were involved in the study. 163 whole body examinations (twice in 12 cases and 3 times in 2 cases) were performed after injection of 18F-fluro-deoxy-glucose (18FDG) with a Siemens ECAT EXACT HR + PET system. The results of PET were compared with pathological diagnoses (112 cases), clinical follow-up (35 cases), CT (68 malignant and 30 benign cases), and other imaging diagnoses. RESULTS: For the 147 cases with lung lesions, the sensitivity, specificity, and accuracy of FDG PET in differentiating the malignant from the benign were 97.2%, 89.7%, and 94.6% respectively. For the 93 lung cancer cases, more lesions were detected by PET in 58 (62.4%) cases, and changed staging in 36 (38.7%). In the 98 cases examinations, PET positive findings were consistent with CT in 39 (39.8%) cases; PET detected more lesions than CT in 29 (29.6%) cases; the lesions detected by CT were negative or with low uptake in the PET images in 30 (30.6%) cases, and they were finally proved as benign by follow-up. However, CT provided better detailed anatomical structures of the lesions than PET, and image fusion should give more information about the lesions. CONCLUSIONS: FDG PET had advantages in diagnosing and staging of lung cancer by providing metabolic information of the lesions. Comparison and fusion of PET with CT will give much help to clinical diagnosis.
Type 2 diabetes mellitus is characterized by impaired glucose uptake. With a photometric method of recording the erythrocyte suspension absorption during the course of glucose transport across the membranes, we observed that the initial rate of glucose zero-trans entry was decreased significantly in 30 Chinese type 2 diabetic patients as compared to 25 healthy controls. The rate of glucose infinite-cis efflux exhibited no difference between the patients and controls. The measurement of temperature dependence of glucose transport showed that the activation energy for glucose entry was increased in diabetic patients. The inhibitory constant of glucose entry by cytochalasin B (CB) in patients was similar to that of the controls. However, we found that the inhibitory constant was increased significantly in the patient erythrocytes after phloretin treatment. After the erythrocytes were made into stripped white ghosts, the fluorescence quenching experiment was performed. Glucose, CB and phloretin can quench the fluorescence of tryptophan residues in the glucose transporter 1, GLUT1. The abnormality of fluorescence quenching in the erythrocyte membranes of patients was observed. The transfer tendency of tryptophan residues from the hydrophilic environment to the hydrophobic environment was decreased in patient ghosts as binding with glucose, and the opposite tendency appeared as CB and phloretin instead of glucose. We conclude that the decreased in glucose entry in the erythrocyte membranes of diabetic patients was due to the GLUT1 change in structure - mostly the outer domain of the glucose transporter.
The goal of this study was to identify risk factors for diabetic peripheral sensory neuropathy in type 2 diabetes mellitus in a Chinese population. Peripheral sensory neuropathy was detected by quantitative sensory testing (5.07/10 g monofilament, neurometer and 128-Hz Riedel Seiffert graduated tuning fork). Those who had two or more abnormal quantitative sensory testings were defined as having diabetic sensory neuropathy. Of the 558 non-insulin dependent diabetes mellitits subjects, 62 (11.1%) had peripheral neuropathy. In 59 (10.6%) detection was by monofilament testing, 45 (8.1%) by graduated tuning fork, and 189 (33.9%) by neurometer. In a multivariate logistic regression model, age and insulin therapy were significantly associated with peripheral neuropathy. Age, serum triglyceride, height, and fasting plasma glucose were independently associated with large fiber neuropathy. Our results confirm the previously identified multiple risk factors of diabetic neuropathy. Different quantitative sensory testings detect different nerve fiber defects. The weak correlation between these tests indicates the need to use more than one test in screening for diabetic neuropathy.
Patients with malignant lesions of the adrenal gland may present with a syndrome of excess mineralocorticoids. Both primary hyperaldosteronism and excess mineralocorticoids other than aldosterone resulting from adrenal carcinoma have rarely been reported. In most patients with adrenal tumors secreting mineralocorticoids other than aldosterone, distant metastasis had already occurred at the time of diagnosis and the prognosis was poor. We present a rare case of adrenal cancer with hypertension in a patient with low plasma renin activity and a low plasma aldosterone concentration. The patient's blood pressure returned to normal after removal of the tumor. The patient is still alive and without recurrence 6 years after surgery. This case illustrates the value of thorough evaluation of hypertension and prompt surgical treatment for patients with adrenal cancer.
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The importance of the sympathetic nervous system in the genesis of ventricular arrhythmias associated with acute myocardial ischemia (AMI) was assessed in urethane-chloralose anesthetized cats. AMI was created by a ligation of the left anterior descending coronary artery. All control cats developed ventricular tachyarrhythmia (VT), ventricular fibrillation (VF), bradycardia and hypotension, resulting in 50% mortality. In other groups the paramedian reticular nucleus (PRN) was intermittently stimulated to inhibit the sympathetic nervous system. Both sides of the stellate ganglia (SG) or adrenal glands (AG) were removed to exclude direct effects of cardiac sympathetic nerve or indirect effects of circulatory catecholamines from the adrenal medulla on the heart, respectively. AMI did not affect plasma norepinephrine (NE) and epinephrine (EPI) concentrations in all groups. However, NE concentration was higher in SG removed but lower in AG removed group. Removal of SG and stimulation of PRN significantly reduced arrhythmia score and the incidence of VT, VF and mortality. Removal of AG appeared to be less effective. These findings suggest that cardiac sympathetic innervation is more important than neural and adrenal catecholamine secretions in the plasma.
The oxic radiation response (cytotoxicity) of two heterogeneous murine tumor-cell lines cultured in vitro was studied as a function of the cell's physiological state at the time of X-irradiation. The proliferating (P) 66 and 67 cells displayed equal radiosensitivities; however, the quiescent (Q) cells were considerably more radiosensitive than the P cells, and the 66Q cells were even more radiosensitive than the 67Q cells. Also, the 66Q cells continued to proliferate slowly with about 85 per cent in the G1 phase and 10 per cent in the S phase, while the 67 Q cells displayed a more complete G1 arrest (92-95 per cent). A detailed analysis of the metabolic status vs cell-cycle age (i.e. G1 vs S phase) indicated that the cell-cycle age was the predominant factor influencing radiation-induced cytotoxicity in 67 cells. The data also showed that in the plateau phase Q-cell cultures, pH and cell contact were not influencing factors and that the increased radiosensitivity of the Q cells could not be explained on the basis of energy deprivation. Moreover, the 66Q, but not the 67Q cells displayed an increased sensitivity in addition to that caused by the predominant cell-cycle age shift. This extra increase in radiosensitivity is of unknown metabolic origin, but could be related to cellular membrane fragility in the stressed 66Q cells since this extra component of Q-cell radiosensitivity was reduced both by refeeding (metabolic activation) 4 h before X-irradiation and by delayed plating while incubating the cells in Q medium at 37 degrees C after X-irradiation.
Amino acids and small peptides with different steric configurations and lipophilicities were appended to dopamine. Eighteen compounds have been synthesized. The attachment of D-amino acids or N-methyl amino acids onto the dopamine molecule caused a marked decrease in cardiovascular activity by intravenous injection, while the introduction of lipophilic amino acids caused a marked increase in myocardial contractility and blood pressure in anesthetized dogs. The durations of action were also prolonged.
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