Biomedical subjects

Y Fong

Publications and source records attributed to Y Fong.

At least 145 records · Page 8Linked to original sources

PubMed1996

Hepatic lobar atrophy: association with ipsilateral portal vein obstruction.

OBJECTIVE: This study was performed to evaluate the association between hepatic lobar atrophy, bile duct obstruction, and portal vein obstruction. MATERIALS AND METHODS: Thirty cases of hepatic lobar atrophy identified on angiography with CT during arterial portography from August 1992 to March 1995 were retrospectively reviewed by two independent observers. Cases were evaluated for vascular patency and bile duct obstruction. Malignant diagnoses were present in 28 of 30 patients. RESULTS: Twenty-two patients (73%) had atrophy in the left lobe and eight patients (27%) had right lobar atrophy. Portal vein obstruction was unilateral and confined to the atrophic lobe in 26 patients (87%). In contrast, bile duct obstruction was bilateral in 23 patients (77%) and in only four patients (13%) was it isolated to the atrophic lobe. The correlation between atrophy and portal vein obstruction was significant, with 90% sensitivity, 97% specificity, and 96% positive predictive value (p < .00001). For the correlation between atrophy and biliary obstruction, the sensitivity of angiography with CT during arterial portography was 90%, specificity was 23%, and positive predictive value was 54% (p = .17). CONCLUSION: Hepatic lobar atrophy usually occurs in the setting of combined biliary and portal vein obstruction. A significant correlation exists between hepatic lobar atrophy and ipsilateral portal vein obstruction.

Adult↗

PubMed1996

Malignant hepatic hilar tumors: can ultrasonography be used as an alternative to angiography with CT arterial portography for determination of resectability?

Nineteen consecutive patients with malignant hilar obstruction were imaged with angiography, CT portography, and ultrasonography with color and spectral Doppler technique; all had surgical pathologic correlation. At surgery, 12 of 19 patients (63%) were found to have portal vein involvement; 15 of 19 (79%) had parenchymal invasion; and 11 of 19 (58%) had lobar atrophy. Level of biliary obstruction was determined in seven of 19 patients (37%) without drainage catheters. No difference was found between ultrasonography and angiography with CT portography for diagnosis of atrophy, level of bile duct obstruction, hepatic involvement, or venous invasion. Extrahepatic metastases in nine of 19 patients (47%) were poorly predicted by both CT portography and ultrasonography.

Adult↗

PubMed1996

Proximal bile duct tumors.

Modern radiologic diagnostic approaches that identify patients with high bile duct cancer can predict resectability and provide information for biliary-enteric bypass in the case of irresectability. Twenty percent to 40% of patients are resectable by local excision with or without hepatic resection, and this represents the only opportunity for cure. Operative mortality is now acceptable and resection is associated with a median survival of approximately 35 months. Numerous palliative operative and nonoperative approaches are available, including biliary-enteric bypass, transtumoral stenting, and percutaneous endoprostheses. The role of both intraluminal and external beam radiotherapy also is discussed.

Bile Duct Neoplasms↗

PubMed1996

Surgical resection of metastatic liver tumors.

The liver is a common site of metastatic cancers. Abundant data now support surgical resection as the treatment of choice for metastatic colorectal cancer to the liver. For symptomatic neuroendocrine tumors, resection also is a useful palliative therapy. Roles for resection of metastatic cancer from other primary sites have yet to be defined.

Carcinoma↗

PubMed1995

Utility of routine chest radiographs in the surgical intensive care unit. A prospective study.

OBJECTIVES: To correlate patient condition and reasons for obtaining chest radiographs (CXRs) with the utility of CXRs in critical illness and to determine the potential impact of stricter criteria for obtaining a CXR in a surgical intensive care unit (ICU). DESIGN: Inception cohort study of 1003 CXRs examined prospectively. PATIENTS AND SETTING: A total of 157 consecutive patients admitted to the general surgical ICU of a 780-bed, urban, university-affiliated, tertiary care hospital. INTERVENTION: Nothing was done to influence the ordering of CXRs. OUTCOME MEASURES: Influence of CXR findings on clinical management. RESULTS: The likelihood of a clinically important finding was 17% for CXRs obtained for no clear clinical indication (routine), 26% for those obtained to verify the position of a medical device, and 30% for those obtained for suspected clinical conditions. By univariate analysis, suspected pathophysiologic condition, admission APACHE II (Acute Physiology and Chronic Health Evaluation II) score, presence of a central venous or Swan-Ganz catheter, and length of ICU stay were all predictors of a significant finding. By multivariate analysis, the only independent predictor of a finding was a suspected clinical condition, and the only indwelling medical device that was an independent predictor of a finding was a Swan-Ganz catheter. If the criterion that routine CXRs should only be obtained in patients with Swan-Ganz catheters had been used, 200 CXRs would have been avoided during the 3-month study period. The only findings missed by not obtaining those CXRs would have been two malpositioned nasogastric tubes and one malpositioned central venous catheter. CONCLUSIONS: Chest radiographs should only be obtained on surgical ICU patients for specific indications. Routine CXRs for ICU patients are justified only for patients with indwelling Swan-Ganz catheters.

Adolescent↗

PubMed1995

Palliation of irresectable hilar cholangiocarcinoma with biliary drainage and radiotherapy.

Twelve patients with irresectable or recurrent hilar cholangiocarcinoma were treated with internal biliary drainage followed by intraluminal (iridium-192) and external-beam radiotherapy. Biliary drainage was accomplished by means of a combined surgical and interventional radiological approach. Initial biliary decompression was performed surgically by tumour resection, intrahepatic biliary enteric bypass or distal biliary-enteric anastomosis with a temporary stent. Maintenance of internal biliary drainage and application of intraluminal radiotherapy were accomplished radiologically with the use of percutaneous dilatation and metallic expandable biliary endoprostheses. Median survival was 14.5 months; all 12 patients survived for at least 6 months. Early complications during radiotherapy were minor and included two patients with cholangitis and one with transient haemobilia. Jaundice was relieved in ten of 12 patients, while episodes of cholangitis were seen during long-term follow-up in 11 (median 1.5 episodes per patient). Internal biliary drainage, in conjunction with radiotherapy, appears to be safe and effective palliation of irresectable or recurrent hilar cholangiocarcinoma. Patients can maintain a reasonable quality of life with an acceptable incidence of cholangitis, without the hindrance of external drainage devices.

Aged↗

PubMed1995

Surgical options in the treatment of hepatic metastasis from colorectal cancer.

Current data indicate that liver resection is the only available treatment that regularly produces long-term survival with possible cure in patients with metastatic colorectal carcinoma to the liver. Although a number of clinical or pathologic factors predicts a poor outcome, the only absolute contraindications to liver resection are general health incompatible with recovery from major hepatic resection or clear evidence of wide dissemination of disease. Important areas for future study include the potential role of adjuvant regional chemotherapy after resection and cryoablation of "close" margins. For patients with unresectable disease, operative therapy also plays an important role. Multiple operative modalities hold promise in palliative treatment in the setting of clinically incurable disease. It is imperative that a large randomized trial of regional chemotherapy be performed allowing no crossover and with mortality as an endpoint. Additionally, the role of cryoablation begs systematic investigation to ensure proper use of this modality.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1995

Pancreatic or liver resection for malignancy is safe and effective for the elderly.

BACKGROUND: Liver resection, or pancreaticoduodenectomy, has traditionally been thought to have a high morbidity and mortality rate among the elderly. Recent improvements in surgical and anesthetic techniques, an increasing number of elderly patients, and an increasing need to justify use of limited health care resources prompted an assessment of recent surgical outcomes. METHODS: Five hundred seventy-seven liver resections (July 1985-July 1994) performed for metastatic colorectal cancer and 488 pancreatic resections (October 1983-July 1994) performed for pancreatic malignancies were identified in departmental data bases. Outcomes of patients younger than age 70 years were compared with those of patients age 70 years or older. RESULTS: Liver resection for 128 patients age 70 years or older resulted in a 4% perioperative mortality rate and a 42% complication rate. Median hospital stay was 13 days, and 8% of the patients required admission to the intensive care unit (ICU). Median survival was 40 months, and the 5-year survival rate was 35%. No differences were found between results for the elderly and those for younger patients who had undergone liver resection, except for a minimally shorter hospital stay for the younger patients (median, 12 days vs. 13 days; p = 0.003). Pancreatic resection for 138 elderly patients resulted in a mortality rate of 6% and a complication rate of 45%. Median stay was 20 days, and 19% of the patients required ICU admission, results identical to those for the younger cohort. Long-term survival was poorer for the elderly patients, with a 5-year survival rate of 21% compared with 29% for the younger cohort (p = 0.03). CONCLUSIONS: Major liver or pancreatic resections can be performed for the elderly with acceptable morbidity and mortality rates and possible long-term survival. Chronological age alone is not a contraindication to liver or pancreatic resection for malignancy.

Age Factors↗

PubMed1995

Rapid and efficient gene transfer in Human hepatocytes by herpes viral vectors.

Retroviral vectors have been widely studied as vehicles for hepatocyte gene therapy, but they are limited by an inability to infect nondividing cells and the need for prolonged cell culture. Two replication deficient herpes simplex viral vectors (HSV) were constructed with the marker genes lac-Z/beta-galactosidase (HSVlac) or human-growth hormone (HSVhGH) to determine the efficiency of HSV gene transfer into adult human hepatocytes. Hepatocytes were isolated by collagenase perfusions and density centrifugation from liver wedge biopsy specimens obtained from six patients. After exposure to HSV (0, 50,000 and 500,000 viral particles/ 10(6) hepatocytes) for 20 minutes, 1 hour, or 2 hours, the hepatocytes were washed and placed in culture. Hepatocytes transduced with HSVlac were fixed at 24 hours and histochemically stained with X-gal, and media from HSVhgh-transduced cells were assayed at 48 hours by radioimmunoassay for hGH. After a 20-minute exposure at a multiplicity of infection of 0.5 (1 viral particle per 2 hepatocytes), greater than 35% of the hepatocytes expressed the lac-Z gene ( > 70% efficiency). hGH was also detected in the media from HSVhGH-transduced cells, showing that proteins coded for by foreign cells are not only expressed by transduced cells but are also secreted. Isolated liver perfusions using HSVlac were also performed in Fischer rats. A 20-minute isolated perfusion using 5 x 10(6) viral particles resulted in expression of the beta-galactosidase gene in the rodent livers 72 hours later without histological signs of tissue injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

A technique for the use of cryosurgery to assist hepatic resection.

BACKGROUND: Wedge or other nonanatomic hepatic resections, performed in an attempt to spare functional parenchyma, often are not accomplished with clear resection margins and may be complicated by hemorrhage from the depth of the resection. STUDY DESIGN: The current study describes a technique of cryoassisted hepatic resection that allows for controlled resection with well-defined margins. The early experience in managing 16 tumors in 13 patients is reported. RESULTS: A cryoprobe is inserted into the tumor and freezing performed to a predetermined resection margin using ultrasound control. The ice ball, so formed, is then maintained and excised. The management of these 13 patients was associated with one intraoperative and two postoperative complications, including a death of a patient with cirrhosis who had infected ascites and died as a result of hepatic failure. CONCLUSIONS: Cryoassisted hepatic resection seems to be safe and allows resection with good tumor clearance and maximal preservation of functional parenchyma.

Cryosurgery↗

PubMed1994

A Drosophila gene promoter is subject to glucose repression in yeast cells.

Previous work has shown that the alpha-amylase gene of Drosophila melanogaster is subject to repression by dietary glucose. Moreover, glucose repression of this gene is mediated by promoter elements that lie upstream of the transcriptional start site. In this study, we examined the activity of the glucose-repressible Drosophila promoter in transformed yeast cells. We show that the amylase promoter region can mediate glucose repression of a heterologous reporter gene in yeast. The implication of this result is that the yeast regulatory machinery can recognize the Drosophila promoter signals. This, in turn, implies an unexpectedly high degree of evolutionary conservation in the mechanism of glucose repression among eukaryotes. It also shows that genes that have acquired complex patterns of developmental regulation-e.g., the Drosophila amylase gene, can still retain, intact, more primitive forms of regulation, such as glucose repression.

Actins↗

PubMed1994

One hundred consecutive hepatic resections. Blood loss, transfusion, and operative technique.

BACKGROUND: Hepatic resection is prone to significant blood loss. Adverse effects of blood loss and transfusion mandate improvements in surgical techniques to reduce blood loss and transfusion requirements. METHODS: One hundred hepatic resections were carried out using a standard surgical technique that includes control of the hilar structures, extrahepatic control of the hepatic veins, and use of the Pringle maneuver. Low central venous pressure and Trendelenburg positioning were used during parenchymal transection. Data were collected retrospectively in the first 36 patients, whereas data were collected prospectively in the remaining 64 patients. RESULTS: Hospital mortality was 3%. Median blood loss was 450, 700, 1000, 1100, and 1500 mL for segmental, nonanatomic, lobar, extended right, and extended left resections, respectively. Major resections were more likely than minor resections to be transfused with albumin (P = .008), fresh frozen plasma (P = .009), and packed red blood cells or whole blood (P = .04). Overall transfusion of packed red blood cells or whole blood occurred in 59 of 100 patients. In the 64 patients who were followed up prospectively, the predeposit of autologous blood decreased the need for homologous transfusions from 56% to 38%. A further reduction in the transfusion rate of 25% could have been possible if all patients in the prospective group had donated 2 U of autologous blood. Patients who predeposited blood were more likely to receive transfusions and to have had a transfusion more than 24 hours after surgery than were patients who did not donate blood. CONCLUSIONS: The surgical techniques used results in acceptable blood loss and transfusion requirements for hepatic resection. This approach is safe, cost-effective, reproducible, and applicable for widespread use.

Adult↗

PubMed1994

Systemic and liver cytokine activation. Implications for liver regeneration and posthepatectomy endotoxemia and sepsis.

BACKGROUND: The liver is known to be an important site of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) production during infection, but local changes in these cytokines after liver resection are unknown. DESIGN: Fischer rats were subjected to 70% hepatectomy or sham operation to determine if hepatic resection alters liver cytokine production and subsequent response to infection. RESULTS: During liver regeneration, circulating IL-6 levels were mildly increased but no expression of TNF-alpha or IL-6 could be detected in the regenerating livers. However, the capacity for the regenerating liver to produce cytokines was intact, since intraperitoneal Escherichia coli endotoxin (2 mg/kg) produced liver cytokine messenger RNA levels in hepatectomized animals comparable to those in pair-fed controls. Systemic response to endotoxin and sepsis was also intact after hepatectomy, as circulating cytokine response was similar between hepatectomized and pair-fed animals after endotoxin administration as well as after cecal ligation and puncture. CONCLUSION: Hepatectomy elicits a circulating cytokine response without effects on liver IL-6 or TNF-alpha production. However, cytokine defense mechanisms are intact during noncomplicated liver regeneration, as indicated by normal TNF-alpha and IL-6 responses to endotoxemia or sepsis. Endotoxemia is a more potent stimulus for liver cytokine production than local trauma or liver regeneration, suggesting that not only the proximity to injury but also the severity and mechanisms of injury determine local cytokine responses.

Animals↗

PubMed1994

Association of perioperative transfusions with poor outcome in resection of gastric adenocarcinoma.

The clinical records of patients identified by a prospective database as having undergone curative gastric resections for adenocarcinoma not involving the gastroesophageal junction were reviewed in order to examine transfusional practices and to determine if perioperative transfusion had an adverse effect on outcome. Between January 1985 and January 1992, 232 patients received such curative resections. The median follow-up for these patients was 19.0 months, whereas median survival for nonsurvivors was 12.3 months. Fifty-eight percent of the patients received transfusion of blood products. Fifty-four percent of these transfusions amounted to less than 2 units of blood products. By chi 2 analysis, advanced stage of disease (p = .03), advanced T-stage of primary tumor (p = .004), and total gastrectomy (p = .04) were associated with greater likelihood of transfusion. By univariate analysis, male sex (p = .004), total gastrectomy (p = .01), advanced stage of disease (p = .000006), high histologic grade of tumor (p = .03), and blood transfusion (p = .006) were predictors of poor outcome. By multivariate analysis using the proportional hazards model with stage, tumor grade, gender, extent of resection, and transfusion as covariates, blood transfusion was an independent predictor of poor outcome (p = .029, hazard 1.74). These results encourage prospective studies of transfusion on cancer recurrence and studies of alternatives to allogeneic blood transfusions in restoration of oxygen-carrying capacity during surgery in patients with gastric cancer.

Adenocarcinoma↗

PubMed1994

Isolated single-lung perfusion with TNF-alpha in a rat sarcoma lung metastases model.

We conducted a trial of isolated lung perfusion using tumor necrosis factor (TNF) in an experimental sarcoma lung metastasis model. In an in vitro experiment, methylcholanthrene-induced sarcoma cells were incubated for 48 hours with 42 micrograms/mL of either human or murine TNF. Controls were incubated with Hank's balanced salt solution. In an in vivo experiment, 23 F344 rats were injected with 10(7) methylcholanthrene-induced sarcoma cells. On day 7, 4 animals were perfused with 210 micrograms of murine TNF, 5 animals were perfused with 420 micrograms of murine TNF, 10 animals underwent isolated lung perfusion with 420 micrograms of human TNF, and 4 animals were injected systemically with 420 micrograms of human TNF. Animals were sacrificed on day 14 and the lung nodules counted. The cells incubated with murine TNF exhibited a 21% decrease in growth (p = 0.07); cells incubated with human TNF showed a 37% decrease in growth (p < 0.05). Animals perfused with 210 micrograms/mL of murine TNF and animals treated by systemically administered human TNF showed no tumor response. Animals perfused with 420 micrograms/mL of murine TNF had 7.8 +/- 14.2 nodules on the left lung and 58.5 +/- 66.0 nodules on the right lung (p = 0.07). Animals perfused with 420 micrograms/mL of human TNF had 21.7 +/- 18.3 nodules on the left lung and 91.7 +/- 66.2 nodules on the right lung (p < 0.01). On the basis of these findings, we conclude that isolated lung perfusion with TNF can be done safely in the rat and is effective in decreasing the growth of sarcoma lung metastases.

Animals↗

PubMed1994

Repeat hepatic resections for metastatic colorectal cancer.

OBJECTIVE: The authors weighed the risks and benefits of repeat liver resections for colorectal metastatic disease. METHOD: In the 6-year period between January 1985 and June 1991, 499 patients underwent liver resections for colorectal metastases at the Memorial Sloan-Kettering Cancer Center. Of these, 25 patients had repeat surgical resections for isolated recurrent disease to the liver. The clinical data for these patients were reviewed. RESULTS: The median interval between the two resections was 11 months. There were no perioperative deaths, and the complication rate was 28%. Median follow-up after the second liver resection is 19 months, with median survival of 17 months for nonsurvivors. Although the median survival after the second resection is 30 months, 20 of the 25 patients have had recurrences with a median disease-free interval of only 9 months. No characteristic of primary or metastatic disease predicted outcome, including time between presentation of the primary and development of liver metastases, disease-free interval after the first liver resection, and bilobar liver involvement. CONCLUSIONS: Although repeat liver resections can be performed safely and improves survival, the likelihood of cure from such resection therapy is low. This likelihood of further recurrences encourage studies of adjuvant or alternative treatments of this population.

Adult↗

PubMed1994

Whole body and splanchnic leucine, phenylalanine, and glucose kinetics during endotoxemia in humans.

To examine the whole body and splanchnic tissue substrate handling during endotoxemia, an intravenous bolus of endotoxin was given to six healthy volunteers during primed, continuous infusions of [1-13C]leucine, [ring-2H5]phenylalanine, and [6,6-2H2]glucose. Whole body protein breakdown, based on whole body Leu and Phe appearance rates (Ra), increased in response to endotoxin given at time 0 (RaLeu 77 +/- 2 mol.kg-1 x h-1, t = 0 h; 88 +/- 6, t = 4 h; P < 0.05) (RaPhe 39 +/- 2 mol.kg-1 x h-1, t = 0; 46 +/- 3, t = 4 h; P < 0.05). Splanchnic amino acid balance (Bal) increased (BalLeu 7 +/- 4 mol.kg-1 x h-1, t = 0; 21 +/- 5, t = 2 h; P < 0.05) (BalPhe 3 +/- 2 mol.kg-1 x h-1, t = 0; 16 +/- 4, t = 2 h; P < 0.05) and can be accounted for by increased splanchnic uptake (Rd) of Phe and Leu (RdLeu 21 +/- 3 mol.kg-1 x h -1, t = 0; 37 +/- 7, t = 120 min; P < 0.05) (RdPhe 10 +/- 3 mol.kg-1 x h-1, t = 0; 24 +/- 5, t = 120 min; P < 0.05). Splanchnic conversion of Leu to ketoisocaproate increased with endotoxin administration (0.7 +/- 0.6 mol.kg-1 x h-1, t = 0; 8 +/- 3, t = 360 min; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Proteins↗

PubMed1994

Cytokine neutralizing strategies in experimental sepsis.

Endotoxemia and bacteremia initiate a cytokine cascade, which may be beneficial to host defense, but in its exaggerated form may be responsible for shock and death. A large amount of experimental and clinical investigation has centered on neutralizing the cytokine cascade in order to prevent the severe pathophysiologic sequelae associated with infection and sepsis. Most of the work has been focused on systemic administration of antibodies for neutralization of specific cytokines, particularly tumor necrosis factor and interleukin-1. Both biologic and fiscal obstacles have prevented this strategy of using specific antibodies from becoming clinical practice. Of the many other strategies under investigation, four are particular exciting: 1) utilization of natural cytokine antagonists, 2) strategies for increasing cytokine clearance, 3) dietary modulation of cytokine production, and 4) gene therapy of sepsis.

Animals↗