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Biomedical subjects

W Li

Publications and source records attributed to W Li.

At least 1,405 records · Page 78Linked to original sources
PubMed1980

Anterior and cervical mediastinoscopy for determining operability and predicting resectability in lung cancer.

Forty-seven (39%) of 120 patients with presumably operable lung cancer were found to have metastatic tumor in mediastinal lymph nodes by mediastinoscopy. Unnecessary thoracotomy was avoided in these 47 patients. Results of anterior mediastinal node biopsy were positive in 16 (38%) of 42 patients with primary tumors of the left lung who were evaluated by anterior mediastinoscopy without resection or division of costal cartilage. Thirty-one (40%) of 78 patients with primary tumors of the right lung had positive results of mediastinal node biopsy as demonstrated by cervical mediastinoscopy. Sixty-seven percent of patients with centrally located tumors, 43% with adenocarcinoma, and 57% with undifferentiated carcinoma had mediastinal lymph node metastasis. Negative results of anterior mediastinoscopy in patients with primary tumors of the left lung predicted resectability in 25 (96%) of 26 instances. Forty-three (91%) of 47 patients with primary tumors of the right lung and negative results of cervical mediastinoscopy had resectable tumors. Anterior mediastinoscopy appears to be as accurate in the evaluation of mediastinal lymph node metastasis in left lung cancer as cervical mediastinoscopy is in the evaluation of right lung cancer.

Adenocarcinoma↗
PubMed1975

Successful use of intra-aortic balloon counterpulsation in the treatment of refractory intraoperative cardiogenic shock.

Intra-aortic balloon counterpulsation (IABC) has been used successfully in the treatment of shock following myocardial infarction. This report describes eight patients who developed medically refractory cardiogenic shock following cessation of cardiopulmonary bypass and who were treated with IABC. None of the eight became balloon dependent and seven of eight (87.5%) left the hospital doing well. The treatment of refractory intra-operative cardiogenic shock represents a new and additional indication for IABC.

Aortic Valve Stenosis↗
PubMedDate not supplied

Evaluation of three antidotes on arsenic toxicity in the common earthworm (Lumbricus terrestris).

The common earthworm (Lumbricus terrestris) is being evaluated in our laboratories as a substitute for mice in metal toxicity studies. These two disparate species have enzymes in common, such as catalase, superoxide dismutase and glutathione-S-transferase. Also, worms respond similarly to these rodents for selenium and nickel toxicity. Worms are less sensitive, however, to metal toxicity. In this study earthworms were challenged with three different arsenic compounds: arsenite, arsenate and the vesicant phenyldichloroarsine (PDA). The median lethal dose for each arsenic compound was determined. The order of toxicity of the arsenic compounds to the worms was PDA > arsenite > arsenate (24 h LD50 values were 189.5, 191.0 and 519.4 mumol kg-1, respectively). Individual mammalian dithiol antidotes, namely the sodium salt of 2,3-dimercapto-1-propanesulfonic acid (DMPS), meso-dimercaptosuccinic acid (DMSA) or 2,3-dimercapto-1-propanol (BAL), were injected into the worms 5 min after various doses of the arsenic compound were administered. The decreases in acute toxicity values were recorded. All three antidotes protected the worms against arsenic toxicity with varying degrees of effectiveness. The protective action for the inorganic arsenic compounds was in the order DMPS > DMSA > BAL. For the organic arsenical, PDA, the most effective antidote was BAL.

Animals↗
PubMedDate not supplied

Flow velocity quantification in human coronary arteries with fast, breath-hold MR angiography.

Measurement of coronary artery flow velocities has, until now, largely required the use of invasive technologies. The authors have implemented a breath-hold magnetic resonance (MR) angiography technique for depicting the coronary arteries and for quantifying flow velocities. The method was tested in flow phantoms and then applied to a series of subjects: 11 subjects were studied at rest, and four were studied before and during pharmacologic stress induced by intravenous adenosine. Flow velocities at rest in the midportion of the right coronary artery were 9.9 cm/sec +/- 3.5 (n = 12); in the proximal left anterior descending coronary artery, they were significantly higher, measuring 20.5 cm/sec +/- 5.2 (n = 6). With adenosine, flow velocities typically increased at least fourfold. The authors conclude that noninvasive measurement of coronary artery flow velocities is feasible with MR angiography; this method may prove useful for determining the physiologic significance of coronary artery stenosis.

Adenosine↗
PubMedDate not supplied

Differentiation between hemangiomas and cysts of the liver with nonenhanced MR imaging: efficacy of T2 values at 1.5 T.

The authors studied the utility of non-contrast-agent-enhanced magnetic resonance (MR) imaging for differentiating cysts and cavernous hemangiomas of the liver. Nineteen patients with hemangiomas (51 lesions) and 16 with cysts (30 lesions) were studied with a 1.5-T MR imager. T2 values were calculated with the two-point method to evaluate the efficacy of T2 values in the differentiation between hemangiomas and cysts of the liver. For lesions larger than 1 cm, the mean T2 value of cysts (306 msec +/- 156) was significantly longer than that of hemangiomas (113 msec +/- 15) (P < .0001); there was no overlap of the ranges for T2 values of hemangiomas and cysts. All cysts larger than 1 cm could be differentiated from hemangiomas by using a threshold T2 value of 140 msec. This study suggests that calculated T2 values permit differentiation between hemangiomas and cysts larger than 1 cm at 1.5 T.

Adult↗
PubMedDate not supplied

Effect of oxygen inhalation on relaxation times in various tissues.

The effect of the oxygen inhalation on relaxation times was evaluated in various tissues, including the myocardium, liver, spleen, skeletal muscle, subcutaneous fat, bone marrow, and arterial blood, with a [1H]MR system. Statistically significant decrease of T1 relaxation times was observed in the myocardium, spleen, and arterial blood after inhalation of 100% oxygen, whereas no significant change was observed in liver, skeletal muscle, subcutaneous fat, or bone marrow. The T2 relaxation time of these tissues did not differ significantly between before and after inhalation of the oxygen. These results indicate that [1H]MRI can be used to evaluate changes with oxygen inhalation and that the effect of the oxygen inhalation on T1 relaxation time is different among various tissues.

Adipose Tissue↗
PubMedDate not supplied

Magnetic resonance urography by breath-hold contrast-enhanced three-dimensional FISP.

The purpose of this study was to present our initial experience with contrast-enhanced MR urography with a breath-hold three-dimensional imaging technique. We performed MR urographic studies in two pigs (four studies) and five human subjects using gadopentetate dimeglumine. The FISP sequence we used was the same as the one used for contrast-enhanced three-dimensional breath-hold angiography. MR three-dimensional urograms were obtained 7-24 minutes after the contrast injection with a dose as low as .03 mmol/kg. The calyces, renal pelves, and ureters were very well visualized. Three-dimensional MR urography can be acquired within a single breath-hold after administration of gadolinium chelates. This technique could become part of a protocol that could potentially lead to a single comprehensive diagnostic workup for suspected ureteral obstruction and gross hematuria.

Adult↗
PubMedDate not supplied

Three-dimensional low dose gadolinium-enhanced peripheral MR venography.

Our initial experience with low dose contrast-enhanced (LCE) peripheral MR venography (MRV) is presented. Five subjects were studied using three-dimensional (3D) fast imaging with a steady-state precession (FISP) sequence. A dose of 60 ml of gadopentetate dimeglumine diluted 1:20 was used. A tourniquet was applied during lower extremity MR venography. The venous anatomy was well depicted with the 3D LCE technique in all subjects. Compared to the two-dimensional (2D) time-of-flight (TOF) technique, acquisition time of 3D LCE MRV was much shorter, images looked sharper, and more veins could be seen. It is not affected by in-plane saturation and can be performed repeatedly because of the low dose of contrast. This technique holds promise for the detection of venous thrombosis and other disorders.

Adult↗