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Biomedical subjects

S L Yang

Publications and source records attributed to S L Yang.

At least 145 records · Page 8Linked to original sources
PubMed1987

Intraoperative ultrasound of the liver. An important adjunctive tool for decision making in the operating room.

Forty-nine patients operated on for liver or other pathologic processes were examined intraoperatively with special ultrasound transducers during surgical exploration of the abdomen. Subjects were evaluated because of known or suspected disease of the liver. All patients were examined using sterile technique. Prospective diagnosis and retrospective analysis of data were used. In 55% of subjects, no new information was obtained. In 19%, new information was gathered that changed the surgical approach. In 14% of patients, new information was obtained but it was such that no change in the therapeutic approach was needed. In 12% of patients, although no new information was gathered by the use of intraoperative ultrasound, a change in the surgical approach and management of the patient was still possible because of intraoperative ultrasound. These studies show that the routine use of ultrasound during intraoperative procedures, particularly when involving hepatic structures, is a clinically useful technique. In many instances, it will change the course of management.

Evaluation Studies as Topic↗
PubMed1987

Pathognomonic scintigraphic finding of hepatic cavernous hemangioma.

Hemangioma is the most common benign tumor of the liver. An accurate diagnosis of such tumor is essential for proper management of patients with hepatic cavernous hemangioma (HCH). Noninvasive diagnosis of HCH can be made using sequential Tc-99m RBC scintigraphy by demonstrating a "perfusion-blood pool mismatch." In addition, a case of HCH was observed which demonstrated peripheral enhancement with subsequent central enhancement on a sequential Tc-99m RBC blood pool scintigraphy. It is felt that this scintigraphic finding is pathognomonic for HCH.

Adult↗
PubMed1987

The periportal collar: a CT sign of liver transplant rejection.

A low-attenuation region around the peripheral portal tracts (periportal collar) was noted on 13 of 43 computed tomographic studies obtained in 17 patients who had undergone 20 orthotopic liver transplantations. This region was then correlated with acute liver transplant rejection. The periportal collar as a sign of rejection has a sensitivity of 1.0, a specificity of 0.86, a negative predictive value of 1.0, and a positive predictive value of 0.62. This sign corresponds histopathologically with the lymphocytic portal infiltration that occurs during acute liver transplant rejection. Though viral hepatitis and nonspecific portal triad edema can also result in a periportal collar, acute liver rejection is strongly suggested when this sign is seen after liver transplantation. Early diagnosis and confirmation of rejection permit faster and more appropriate clinical intervention.

Adolescent↗
PubMed1987

DNA and protein interactions in the regulation of plasmid replication.

As for bacterial and animal viruses that employ different mechanisms for their duplication in a host cell, plasmids have evolved different strategies to assure their hereditary stability or maintenance at a specific copy number during cell growth and division. A characteristic feature of plasmid replication control, however, is an involvement of one or more negatively controlling elements. Furthermore, a majority of the bacterial plasmids examined to date contain direct nucleotide sequence repeats at their origin of replication and encode a replication protein that binds to these repeat sequences. The binding of the replication protein (pi protein) specified by the antibiotic resistance plasmid R6K to a set of 22 base pair direct nucleotide sequence repeats is required for the initiation of replication at each of three origins of replication (alpha, beta and gamma) within a 4 Kb segment of R6K. The pi initiation protein is multifunctional in that it has both positive and negative activities in both controlling the initiation of replication and autoregulating its own synthesis. Similarly, the direct repeats of plasmid R6K and several other plasmid systems play more than one role in plasmid replication. These repeats, termed iterons, are not only required for origin activity but also exert a negative effect on plasmid copy number possibly as a result of their 'titration' of a plasmid encoded replication protein. The properties of plasmid replication proteins and direct nucleotide sequence repeats that are important for their opposing positive and negative roles in the regulation of the initiation of replication are described with particular emphasis on plasmid R6K of Escherichia coli.

Bacterial Proteins↗
PubMed1987

Validation of cognitive and functional assessment instruments in vascular dementia.

Vascular dementia is a common and potentially reversible type of dementing illness. Simple, yet valid, assessment instruments are needed to quantitate the severity of cognitive and functional impairment in vascular dementia patients seen in consultation or studied in therapeutic trails. Among sixty-three patients with known ischemic cerebrovascular disease, we found thirteen who satisfied research criteria for vascular dementia, nineteen who were "borderline" and thirty-one who were not demented. We administered the Cognitive Capacity Screening Examination and the Functional Activities Questionnaire to these patients and found both tests capable of distinguishing demented from nondemented groups with a high degree of sensitivity and specificity. This battery of assessment instruments was especially helpful in evaluating patients who fell into the "borderline" category. Both tests can be easily administered at the bedside or during routine office visits.

Aged↗
PubMed1987

[Kinetic observation and analysis of the radioactivity distribution of 125I-labelled F(ab')2 fragments of monoclonal antibody against human lung cancer cells in normal mice].

Radioactivity distribution of 125I-labelled F(ab')2 fragments in 14 organs and tissues of normal mice for 11 time-phases from 0.5 hour to 7 days after injection was observed. The radioactivity-time curves of these organs and tissues were divided into three types according to their characteristics: excreting type (blood and liver), absorbing type (thyroid), absorbing-excreting type (the other organs and tissues). The organs fully perfused with blood had shorter peak-time and higher peak-value, such as heart, lung, kidney and liver. All of the peak-times were equal to or less than 2 days after injection, therefore the image taking should be kept away from this period. The excreting rate constants of slow metabolic component were similar for various organs and tissues except thyroid and brain. The brain had a low peak in the curve and small excreting rate constant. It was demonstrated that F(ab')2 fragments were able to penetrate the blood-brain barrier but absorption and excretion were slower compared with the other organs and tissues. The radioiodine was obviously concentrated in the subcutaneous tissue, which may have been the main cause of the subcutaneous tissue tumor induced by radioiodine. The radioactivity-time curve in which the peak value and inflect point existed simultaneously shows that radioactivity metabolism after injection of 125I-F(ab')2 follows three compartment models. The biological meanings corresponding to three sections of the blood radioactivity-time curve are pure distribution, distribution-recycle and catabolic-excretory phases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Risk of pulmonary embolus with inferior vena cava thrombosis.

The authors have evaluated the risk of pulmonary embolism both as a primary event or as a secondary embolus despite adequate anticoagulation in 39 patients with phlebographically documented inferior vena caval (IVC) thrombosis. Twenty-six of these patients had thrombi characterized as free floating, and 13 had thrombi that were adherent to the IVC wall without a free-floating component. The incidence of initial pulmonary embolism confirmed by either pulmonary arteriography or high probability ventilation-perfusion lung scanning was 50 per cent (13/26) in those patients with free-floating IVC thrombi, but 15 per cent (2/13) in those with closely adherent mural thrombi (P less than 0.05). Pulmonary embolism despite adequate anticoagulation occurred in 27 per cent (7/26) of patients with free-floating clots, but in only 17 per cent (1/8) of cases with adherent thrombi (P greater than 0.05). These data strongly suggest that patients with documented free-floating inferior vena caval thrombi are at a significant risk for pulmonary embolism as an initial event and perhaps also as a recurrent embolus, even in the presence of adequate anticoagulation. When such thrombi are identified, the overall incidence of pulmonary embolus is high and conventional anticoagulant treatment with heparin may not be sufficient.

Heparin↗
PubMed1986

Antipyrine kinetics in liver disease and liver transplantation.

Antipyrine kinetics were studied in seven normal subjects, 10 patients with liver disease, and 13 clinically stable patients who received a liver transplant. Five patients were studied both before and after liver transplantation. Antipyrine concentrations in saliva after oral dosing were measured by HPLC. The antipyrine t1/2 was significantly longer (P less than 0.05) in patients with liver disease than in patients undergoing liver transplantation and normal subjects. Antipyrine clearance was not significantly different between patients undergoing liver transplantation and normal subjects, but it was significantly reduced (P less than 0.05) in patients with liver disease. In five patients who were studied before and after liver transplantation, there was a significant (P less than 0.05) increase in the antipyrine clearance and a marked reduction in its t1/2 after liver transplantation. These results indicate that liver transplantation improves the drug metabolizing ability of patients with liver disease and that the oxidative metabolizing capacity of the liver in clinically stable patients after liver transplantation is similar to that of normal subjects.

Administration, Oral↗
PubMed1985

Immunoglobulins in prolonged ruptured membranes.

Concentrations of immunoglobulins G, M, and A were studied in maternal and cord serum of patients with prolonged premature rupture of membranes, as well as in properly matched control patients. None of the patients studied showed any evidence of clinical chorioamnionitis or other prenatal infections. Cases were divided into term premature rupture of membranes and term controls and preterm (less than 34 gestational weeks) premature rupture of membranes and preterm controls. In the term group, with 12 to 24 hours of premature rupture of membranes, maternal immunoglobulins M and A, and cord immunoglobulin A were significantly increased. With a duration of premature rupture of membranes of more than 24 hours, levels of immunoglobulins M and A in maternal serum and levels of immunoglobulins G and A in cord serum showed significant elevations. Levels of cord immunoglobulin M from both subgroups of patients with premature rupture of membranes showed a trend upward but were not significantly higher than those in control patients. In the preterm group, with 12 to 24 hours of premature rupture of membranes, only cord immunoglobulin A was significantly increased. With premature rupture of membranes of greater than or equal to 72 hours, only maternal immunoglobulin G increased significantly and remained elevated; immunoglobulins M and A in cord serum were also significantly increased. The significant rise in immunoglobulins in patients with premature rupture of membranes may indicate subclinical maternal and fetal infection. This suggests the possibility that subclinical infections may play a role in the etiology of premature rupture of membranes.

Female↗
PubMed1985

Transvenous catheter pulmonary embolectomy.

Acute cardiovascular collapse in the hospitalized patient is associated with a high mortality rate and remains a therapeutic dilemma. Survival could be improved in the subgroup of patients with massive pulmonary thromboembolism if prompt surgical intervention is undertaken. This report presents the cases of two patients with cardiovascular collapse who survived transvenous catheter pulmonary embolectomy (herein described in detail). This procedure can be performed in any hospital with angiographic facilities and personnel trained in the technique. In our opinion it is the procedure of choice in patients with refractory cardiovascular collapse from massive pulmonary thromboembolism.

Catheterization↗