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Biomedical subjects

S W Fong

Publications and source records attributed to S W Fong.

At least 19 recordsLinked to original sources
PubMed2001

Inhibition of androgen-sensitive LNCaP prostate cancer growth in vivo by melatonin: association of antiproliferative action of the pineal hormone with mt1 receptor protein expression.

BACKGROUND: Potential involvement of the mt1 receptor in the antiproliferative action of melatonin on androgen-sensitive LNCaP cells, and melatonin-induced modulation of androgen-insensitive PC-3 cell growth, have been reported in vitro. The effects of melatonin on prostate cancer cell proliferation and their association with mt1 receptor expression were investigated in athymic nude mice xenograft models of LNCaP and PC-3 cells. METHODS: Daily saline or melatonin (4 microg/g body weight) was given to nude mice before or after tumor cell inoculation. Tumor volume was measured periodically, and expression of PCNA, cyclin A, PSA, and mt1 receptor was assessed by immunohisto(cyto)chemistry and/or Western blotting. RESULTS: Melatonin inhibited the growth of LNCaP tumors, without affecting the growth of PC-3 xenografts, in nude mice. It induced significant decreases in the expression of PCNA, cyclin A, and PSA in LNCaP tumors. Expression of mt1 receptor protein was demonstrated in LNCaP cells, but not in PC-3 cells, both in vivo and in vitro. CONCLUSIONS: The antiproliferative action of melatonin on LNCaP tumor growth was demonstrated in vivo, and its association with mt1 receptor protein expression suggests the potential involvement of the receptor in the antitumor activity of the pineal gland hormone.

Animals↗
PubMed1977

Extracorporeal membrane oxygenator support for cardiopulmonary failure. Experience in 28 cases.

We have used extracorporeal membrane oxygenation (ECMO) for 28 patients (14 children and 14 adults) over a 5 year period. Nine patients improved on ECMO and 5 were long-term survivors. ECMO was used for pulmonary insufficiency in 24 patients. Initially, only moribund patients were treated, but recently the combination of open lung biopsy and pulmonary insufficiency index (PII) has been used to select patients. The best results have been obtained in newborn cases and the adult capillary leak syndromes; the major problem has been progression to fibrosis despite ECMO support. ECMO was used for cardiac failure in 4 patients. Children with postoperative cardiac failure did the best; profound shock was not reversed with venoarterial bypass. ECMO support is lifesaving in selected cases of pulmonary insufficiency. Initial trials in cardiac failure and the infant age group in this series suggest that ECMO will have an even greater role in those applications.

Adolescent↗
PubMed1976

Blood coagulation studies during six day heparinless venoarterial bypass in sheep.

Heparinless venoarterial bypass (HL-VAB) was carried out in 16 sheep for 6 days, by means of a closed circuit tubing coated with nonthrombogenic polyurethane-polyvinyl-graphite (PPG) and a roller pump. Nine experiments were completed uneventfully. Seven sheep died during bypass. The causes of death were pneumonia (2), caseous granulomatous lung abscess (3) or abdominal abscess (1), and thromboembolism (1). The last complication was caused by inadverten trauma to the PPG coating at the time of tubing connection. In the animals in which HL-VAB was uneventful, no significant changes were noted in the hematologic studies including white blood counts, platelet counts, hematocrit, plasma fibrinogen levels, prothrombin time, thrombin time, activated partial thromboplastin time, Factors V and VIII, and free plasma hemoglobin levels. Inconsistant changes in the above parmeters were noted in the animals which died of complications. In conclusion, prolonged HL-VAB has no adverse effects on blood coagulation mechanism.

Animals↗
PubMed1976

Extracorporeal membrane oxygenation (ECMO) cardiopulmonary support in infancy.

We have used prolonged extracorporeal membrane oxygenation (ECMO) in the treatment of 13 moribund infants (including 9 neonates), with 4 survivors (3 neonates). Successfully treated cases include post-operative cardiac failure, infant respiratory distress syndrome, massive meconium aspiration, and persistent fetal circulation. All cases have been managed with veno-arterial bypass at flow rates of 80-100 cc/Kg/min. Carotid cannulation for arterial access and careful control of heparin anticoagulation based on whole blood activated clotting time are among the techniques which have contributed to this success. Progressive pulmonary or cardiac failure has been the major problem in older infants, intracranial bleeding is the major problem in neonates. Both of these problems could be minimized by instituting ECMO earlier in the clinical course, but this awaits development of reliable early predictors of mortality.

Blood Coagulation↗
PubMed1975

Hematologic responses to prolonged extracorporeal circulation (ECC) with microporous membrane devices.

Twenty-four to 48 hr veno-arterial bypass with microporous membrane oxygenators causes moderate progressive thrombocytopenia associated with decreased platelet function, no significant change in clotting factors, fibrinogen, or the fibrinolytic system, and minimal change in white blood count, differential, and plasma hemoglobin. These effects are identical to those seen in previous studies following the same protocol with solid silicone rubber membrane oxygenators. Microporous membrane is suitable for prolonged extracorporeal support systems. This study suggests that the deleterious effects of a direct blood gas interface are caused by continuous renewal of the surface rather than the nature of the interface itself.

Adenosine Diphosphate↗
PubMed1974

Prolonged partial venoarterial bypass: physiologic, biochemical, and hematologic responses.

Prolonged veno arterial extracorporeal bypass (50-80% of cardiac output) was evaluated in normal, unanesthetized sheep. The evaluation protocol included serial measurements of hemodynamics, pulmonary and renal function, serum enzymes to detect organ damage, and detailed studies of coagulation and platelets. Blood exposure surfaces were primarily polyvinyl chloride and silicone rubber. Gas interfaces were carefully excluded with the exception of four experiments utilizing bubble oxygenators. Heparin dose was titrated to maintain activated clotting to two to three times baseline. Characteristics of 48 hour uncomplicated extracorporeal circulation in 8 sheep included normal hemodynamics, mild respiratory alkolosis negligable hemolysis, slight gradual increase in heart, liver, and muscle enzymes. The most significant changes occurred in coagulation and platelets characterized by an initial reduction in coagulation factors with a continued reduction in platelet count and return to normal clotting factors during extracorporeal circulation. This is followed by a two times normal increase in platelets and fibrinogen following extracorporeal circulation.

Acid-Base Equilibrium↗