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Biomedical subjects

J Wong

Publications and source records attributed to J Wong.

At least 253 records · Page 14Linked to original sources
PubMed1999

Prevalence of significant carotid stenosis in Chinese patients with peripheral and coronary artery disease.

BACKGROUND: The prevalence of extracranial carotid stenosis in the Chinese population is not known. This study aims to investigate and compare carotid disease in several groups of high-risk patients. METHOD: Routine screening carotid duplex scans were performed on high-risk Chinese patients without cerebrovascular symptoms. These consisted of 249 patients with peripheral vascular disease, 207 patients with coronary artery disease, and 45 patients with abdominal aortic aneurysm. In addition, 220 patients with cerebrovascular symptoms and 58 patients with carotid bruits were scanned. A group of 108 healthy individuals was included as a control. The data of all 887 subjects were analysed. RESULTS: Carotid stenosis of 70% or greater was detected in 37.7% of patients in the cerebrovascular disease group and 24.5% of patients with peripheral arterial disease; it was higher than in patients with coronary artery disease (11.1%), asymptomatic carotid bruit (10.3%) and aortic aneurysms (8.9%; P < 0.001). No significant disease was found in the controls. Patients with cerebrovascular disease have more severe degrees of carotid stenosis and significantly more total occlusions. Smoking, age and male sex were the main risk factors for high-grade (> or = 70%) carotid stenosis. CONCLUSION: The prevalence of extracranial carotid stenosis in Chinese patients is not low. Patients with peripheral arterial disease have the highest risk of significant carotid stenosis: routine carotid duplex screening in these patients is recommended.

Aged↗
PubMed1999

Esophageal carcinoma in a patient with bleeding esophageal varices.

More than 20 cases of esophageal carcinoma have been reported to develop after endoscopic injection sclerotherapy (EIS), and this technique is implicated in the pathogenesis of esophageal cancer. We report a case of esophageal carcinoma presenting as a superficial ulcer in a patient with esophageal varices with no prior EIS. Whether the development of esophageal carcinoma in patients with previous EIS is coincidental or consequential is controversial. Such carcinoma might have already existed before EIS in some reported cases. A causal relationship between EIS and esophageal carcinoma cannot be established without further clarification by a well-designed study.

Adenocarcinoma↗
PubMed1999

Administration of daniplestim and granulocyte colony-stimulating factor for the mobilization of hematopoietic progenitor cells in nonhuman primates.

We investigated the effects of administering a high-affinity interleukin-3 receptor agonist (daniplestim) and granulocyte colony-stimulating factor (G-CSF) on the mobilization of primitive hematopoietic progenitor cells into peripheral blood (PB). Groups of five rhesus monkeys were treated with 100 mg/kg of daniplestim for 5 days followed by 10 microg/kg of G-CSF for 5 days (D/G), daniplestim and G-CSF administered concurrently for 10 days (D+G), or G-CSF alone for 10 days. Phenotypic PB analysis indicated that the number of CD34+ cells in the G-CSF group had increased to 28 x 10(6)/L by Day 3 and then declined. In contrast, CD34+ cell counts of up to 68 x 10(6)/L were maintained until Day 10 in both the D/G and D+G groups. On Day 5, the total number of colony-forming cells in the PB had increased 15-fold in the D+G group and eightfold in both the D/G group and the G-CSF groups. By Day 7, the numbers of colony-forming units granulocyte/macrophage were comparable in all three groups, and 45-fold increases in the numbers of burst-forming units-erythroid and 12-fold increases in the numbers of multipotent colony-forming units were seen in both the D+G and the D/G groups. The frequency of circulating primitive progenitor cells in long-term stromal cultures was highest with D+G and lowest with G-CSF alone. These results indicate that the combination of daniplestim and G-CSF produces higher and more sustained levels of circulating stem cells than does G-CSF alone. D+G may offer advantages over D/G because it generates more long- and short-term clonogenic cells.

Animals↗
PubMed1999

Malignant melanoma of the oesophagus: clinicopathological features, lack of p53 expression and steroid receptors and a review of the literature.

AIMS: Fortunately, primary malignant melanoma of the oesophagus is a rare entity. The aims of this study were to evaluate the clinicopathological features, p53 over-expression and steroid receptors in oesophageal melanomas and to review the reported cases in the literature. METHODS: Melanomas reported during a 15-year period (1982-1996) in the Queen Mary Hospital were studied. The clinicopathological features and survival data of patients with oesophageal melanomas were noted. Representative tissue was collected from each tumour and immunohistochemical preparations for HMB-45, p53, oestrogen and progesterone receptors were made. A review of oesophageal melanomas reported in the literature was also performed. RESULTS: Three cases of primary malignant melanoma of the oesophagus were found. They accounted for 3% of melanomas and 0.2% of oesophageal cancers diagnosed. The melanomas were fusiform and large at the time of resection. All three patients died of their malignancy within 9 months of operation. The tumours stained positive for HMB-45 and were negative for p53, oestrogen and progesterone receptors. From previous reports, 154 oesophageal melanomas were documented. The tumours were fusiform, large, often pigmented and located in either the middle or lower oesophagus. Although many oesophageal melanomas presented at early stages (stages I or II), their biological behaviour was aggressive. The 5-year survival rate was 5.7%. CONCLUSIONS: Melanoma of the oesophagus is an aggressive tumour. There is no evidence for the p53 gene and female sex hormones having a role in the development or progression of the tumour.

Aged↗
PubMed1999

Intrahepatic recurrence after curative resection of hepatocellular carcinoma: long-term results of treatment and prognostic factors.

OBJECTIVE: This study aimed to evaluate the long-term results of treatment and prognostic factors in patients with intrahepatic recurrence after curative resection of hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: Recent studies have demonstrated the usefulness of re-resection, transarterial oily chemoembolization (TOCE), or percutaneous ethanol injection therapy (PEIT) in selected patients with intrahepatic recurrent HCC. The overall results of a treatment strategy combining these modalities have not been fully evaluated, and the prognostic factors determining survival in these patients remain to be clarified. METHODS: Two hundred and forty-four patients who underwent curative resection for HCC were followed for intrahepatic recurrence, which was treated aggressively with a strategy including different modalities. Survival results after recurrence and from initial hepatectomy were analyzed, and prognostic factors were determined by univariate and multivariate analysis using 27 clinicopathologic variables. RESULTS: One hundred and five patients (43%) with intrahepatic recurrence were treated with re-resection (11), TOCE (71), PEIT (6), systemic chemotherapy (8) or conservatively (9). The overall 1-year, 3-year, and 5-year survival rates from the time of recurrence were 65.5%, 34.9%, and 19.7%, respectively, and from the time of initial hepatectomy were 78.4%, 47.2%, and 30.9%, respectively. The re-resection group had the best survival, followed by the TOCE group. Multivariate analysis revealed Child's B or C grading, serum albumin < or = 40 g/l, multiple recurrent tumors, recurrence < or = 1 year after hepatectomy, and concurrent extrahepatic recurrence to be independent adverse prognostic factors. CONCLUSIONS: Aggressive treatment with a multimodality strategy could result in prolonged survival in patients with intrahepatic recurrence after curative resection for HCC. Prognosis was determined by the liver function status, interval to recurrence, number of recurrent tumors, any concurrent extrahepatic recurrence, and type of treatment.

Adult↗
PubMed1999

Hepatectomy for hepatocellular carcinoma: toward zero hospital deaths.

OBJECTIVE: The authors report on the surgical techniques and protocol for perioperative care that have yielded a zero hospital mortality rate in 110 consecutive patients undergoing hepatectomy for hepatocellular carcinoma (HCC). The hepatectomy results are analyzed with the aim of further reducing the postoperative morbidity rate. SUMMARY BACKGROUND DATA: In recent years, hepatectomy has been performed with a mortality rate of <10% in patients with HCC, but a zero hospital mortality rate in a large patient series has never been reported. At Queen Mary Hospital, Hong Kong, the surgical techniques and perioperative management in hepatectomy for HCC have evolved yearly into a final standardized protocol that reduced the hospital mortality rate from 28% in 1989 to 0% in 1996 and 1997. METHODS: Surgical techniques were designed to reduce intraoperative blood loss, blood transfusion, and ischemic injury to the liver remnant in hepatectomy. Postoperative care was focused on preservation and promotion of liver function by providing adequate tissue oxygenation and immediate postoperative nutritional support that consisted of branched-chain amino acid-enriched solution, low-dose dextrose, medium-chain triglycerides, and phosphate. The pre-, intra-, and postoperative data were collected prospectively and analyzed each year to assess the influence of the evolving surgical techniques and perioperative care on outcome. RESULTS: Of 330 patients undergoing hepatectomy for HCC, underlying cirrhosis and chronic hepatitis were present in 161 (49%) and 108 (33%) patients, respectively. There were no significant changes in the patient characteristics throughout the 9-year period, but there were significant reductions in intraoperative blood loss and blood transfusion requirements. From 1994 to 1997, the median blood transfusion requirement was 0 ml, and 64% of the patients did not require a blood transfusion. The postoperative morbidity rate remained the same throughout the study period. Complications in the patients operated on during 1996 and 1997 were primarily wound infections; the potentially fatal complications seen in the early years, such as subphrenic sepsis, biliary leakage, and hepatic coma, were absent. By univariate analysis, the volume of blood loss, volume of blood transfusions, and operation time were correlated positively with postoperative morbidity rates in 1996 and 1997. Stepwise logistic regression analysis revealed that the operation time was the only parameter that correlated significantly with the postoperative morbidity rate. CONCLUSION: With appropriate surgical techniques and perioperative management to preserve function of the liver remnant, hepatectomy for HCC can be performed without hospital deaths. To improve surgical outcome further, strategies to reduce the operation time are being investigated.

Adolescent↗
PubMed1999

The clinicopathological significance of p21 and p53 expression in esophageal squamous cell carcinoma: an analysis of 153 patients.

OBJECTIVE: The p21 gene is thought to play a central role in tumor suppression. The aim of this study was to examine the clinicopathological role of p21 and p53 in esophageal squamous cell carcinomas. METHODS: The expression of p21 and p53 proteins in 153 Chinese patients (131 men, 22 women) with resected esophageal squamous cell carcinomas was investigated by the immunohistochemical method. Correlation between p21 and p53 expression and clinicopathological features was examined. RESULTS: The expression of p21 and p53 was detected in 70% and 64% of the tumors, respectively. The staining of p21 and p53 was also found in squamous carcinoma in situ, dysplasia, and nontumor epithelium. p21 expression was often weak in the suprabasal cells and found in better differentiated tumors. There was no significant correlation between the expression of p21 and the abnormal accumulation of p53. The prognosis of the patients depended on the size, stage, and p21 expression of the lesion. In stage III lesions with tumor diameter < or = 7.5 cm (n = 93), patients with loss of p21 expression had better survival. The survival rates of patients were worse if they had expression of both p21 and p53. CONCLUSIONS: Thus, p21 and p53 had prognostic value for esophageal squamous cell carcinomas. Loss of p21 expression was shown without p53 alternations, indicating that other mechanisms are also involved in turning off the gene. The pattern of p21 and p53 expression predicts an aggressive clinical course of esophageal squamous cell carcinomas.

Actuarial Analysis↗
PubMed1999

Hepatocellular carcinoma in the elderly: results of surgical and nonsurgical management.

OBJECTIVE: This study evaluated the results of surgical and nonsurgical treatments of hepatocellular carcinoma (HCC) in the elderly to determine the optimal management strategy. METHODS: Clinicopathological data and treatment results of 222 elderly (> or = 70 yr) and 1116 younger patients with HCC managed between 1989 and 1997 were prospectively collected and compared between the two groups. RESULTS: The resection rate in the elderly (14%) was lower than in younger patients (27%) (p < 0.001). Among patients who underwent resection, there were no significant differences in morbidity rate (48% vs 40%, p = 0.354), hospital mortality rate (10% vs 6%, p = 0.431), or long-term survival (median, 38 vs 42 months, p = 0.940). Comparing the periods 1989-1992 and 1993-1997, hospital mortality rate in the elderly was reduced from 25% to 4% (p = 0.079). Sixty-seven elderly and 317 younger patients underwent transarterial oily chemoembolization (TOCE), with similar morbidity rate (24% vs 26%, p = 0.775), mortality rate (7% vs 5%, p = 0.365), and long-term survival (median, 12 vs 9 months, p = 0.277). The results of other nonsurgical treatments were also similar between the two groups. CONCLUSIONS: Hepatic resection for HCC is safe in selected elderly patients, and the improved results in recent years indicate that more elderly patients could benefit from surgical management. TOCE is well tolerated in elderly patients and is the treatment of choice for unresectable HCC. The overall management strategy of HCC in the elderly should not be different from that in younger patients.

Age Factors↗
PubMed1999

Genetically determined obesity in Prader-Willi syndrome: the ethics and legality of treatment.

A central characteristic of people with Prader-Willi Syndrome (PWS) is an apparent insatiable appetite leading to severe overeating and the potential for marked obesity and associated serious health problems and premature death. This behaviour may be due to the effects of the genetic defect resulting from the chromosome 15 abnormalities associated with the syndrome. We examine the ethical and legal dilemmas that can arise in the care of people with PWS. A tension exists between a genetic deterministic perspective and that of individual choice. We conclude that the determination of the capacity of a person with PWS to make decisions about his/her eating behaviour and to control that behaviour is of particular importance in resolving this dilemma. If the person is found to lack capacity, the common law principles of acting in a person's "best interests" using the "least restrictive alternative" may be helpful. Allowing serious weight gain in the absence of careful consideration of these issues is an abdication of responsibility.

Adolescent↗
PubMed1999

A mouse with a monoclonal primary immunoglobulin repertoire not further diversified by V-gene replacement.

We have generated a monoclonal B-cell mouse by introducing homozygous, nonfunctional RAG-2 alleles and a lambda1 light-chain transgene into the quasi-monoclonal (QM) mouse, which contains a "knocked-in" V(H)DJ(H) rearrangement. Thus, this mouse, which we call MonoB, is devoid of T cells and contains preformed heavy- and light-chain genes encoding immunoglobulin with an anti-NP specificity. The MonoB mouse allows us to examine immunoglobulin diversity in the absence of processes mediated by V(D)J recombination and T cells. Here we report that not only is the MonoB's primary immunoglobulin repertoire monoclonal, but also that its secondary repertoire is not further diversified by V-gene replacement or gene conversion. Among 99 heavy-chain and 41 lambda light-chain genes from peripheral B cells of the MonoB mouse, there were no V-gene replacements. When compared to the QM mouse, which has RAG activity, and for which V-gene replacement is the major diversifying mechanism, these data suggest that V-gene replacement is mediated by V(D)J recombination and not by other recombination systems.

Animals↗
PubMed1999

Effects of granulosa cells, cumulus cells, and oocyte density on in vitro fertilization in women.

The objective of this study was to determine if in vitro fertilization (IVF) rate is affected by the diameter of oocyte-cumulus complex (OCC), by coculturing oocytes with autologous granulosa cells, or by increasing the oocyte density in culture medium. Women with previous fertility problems underwent the IVF program. In study 1, the diameter of OCC was graded on retrieval on a scale of 0-3: grade 0 = no cumulus at all; grade 1 = diameter of 75-100 microm; grade 2 = diameter of 125-150 microm; and grade 3 = diameter of 200-225 microm. In study 2, oocytes were cocultured with autologous granulosa cells. In study 3, oocytes were cocultured in groups of one, two, or four. OCCs with a grade > 1.5/3 resulted in a greater (P = 0.04) proportion of embryo/oocyte than did OCCs with a grade < 1.5/3 (0.91 +/- 0.05 vs 0.68 +/- 0.10; mean +/- SEM). Coculturing oocytes with autologous granulosa cells did not affect (P = 0.42) the proportion of embryo/oocyte (0.63 +/- 0.11 vs 0.74 +/- 0.07 in controls). Coculturing oocytes in groups of two or four in culture drop did not affect (P = 0.37 and P = 0.38, respectively) the proportion of embryo/oocyte (0.63 +/- 0.07 vs 0.73 +/- 0.08 in controls, and 0.73 +/- 0.08 vs 0.63 +/- 0.08 in controls, respectively). In conclusion, coculturing oocytes with autologous granulosa cells or increasing the oocyte density from 1 to 2 or 4 oocytes/culture drop, in the context of our study, did not affect rate of IVF and embryo formation. The diameter of OCC at retrieval may give some indication regarding its future fertilization and development. This diameter varies with the type of ovarian stimulation and the patient's age. This variation in diameter does not correlate with oocyte maturity.

Cell Communication↗
PubMed1999

Immediate stenting of iliofemoral occlusive lesions: a surgeon's early experiences.

PURPOSE: To report the early and midterm results of balloon angioplasty and immediate stenting of atherosclerotic iliofemoral lesions in an operating room setting. METHODS: Sixty-one patients (41 men, mean age 70 +/- 8 years, range 49 to 86) underwent balloon dilation and systematic stenting for 80 stenotic and occlusive lesions in the iliac (n = 47) and superficial femoral (n = 33) arteries in 72 limbs. One hundred two stents (63 VascuCoil, 33 Wallstent, and 6 miscellaneous) were placed. Patients were followed with serial duplex scans at 3-month intervals. RESULTS: Initial technical success by intention-to-treat was 96.2% (77/80) (iliac: 100%, femoral: 90.9% [30/33]). There were 9 (11.3%) procedure-related complications and no deaths. Initial success by anatomic, hemodynamic, and clinical limb criteria were 100%, 95%, and 94.4%, respectively. Thirty procedures were performed for limb salvage with a success rate of 86.7%. Six patients (7 limbs) died during follow-up of unrelated causes. Fifty-nine (81.9%) limbs were available for duplex follow-up over a mean 17.7 months (range 3 to 37). Cumulative patency rates were 87.3% at 2 years for iliac stents and 66.6% at 18 months for femoral stents with an overall 2-year patency rate of 76.3%. The only independent risk factors affecting late patency were the site of angioplasty, stent diameter, lesion grade, and the preoperative ankle-brachial index. Stents placed with a diameter < or = 5 mm and > 5 mm had 1-year patency rates of 51.0% and 97.6%, respectively (p = 0.004) CONCLUSIONS: Iliac and femoral angioplasty and immediate stenting have acceptable midterm patency rates. The patency of femoral stenting is inferior and is adversely affected by stents < or = 5 mm in diameter.

Aged↗
PubMed1998

Long term prognosis after hepatectomy for hepatocellular carcinoma: a survival analysis of 204 consecutive patients.

BACKGROUND: Intrahepatic recurrence continues to be the main cause of late death among hepatocellular carcinoma patients after hepatic resection. The aims of the current study were to identify the prognostic factors affecting long term survival and to evaluate the clinical value of pTNM classification as a prognostic factor for these patients. The identification of significant prognostic factors plays an important role in the selection of patients for postoperative adjuvant therapy and counseling. METHODS: From January 1989 to August 1995, 204 consecutive patients underwent hepatectomy for hepatocellular carcinoma. The overall cumulative and disease free survival rates for these patients were analyzed. Univariate and multivariate analyses of 16 clinicopathologic factors, including factors associated with pTNM classification, were performed to determine the significant prognostic factors. RESULTS: The median periods of overall cumulative survival and disease free survival were 35 months and 12.4 months, respectively. By univariate analysis, all factors associated with tumor (T) classification, namely, tumor size, vascular invasion, the number of tumor nodules, and tumor localization, were correlated with survival. By Cox regression analysis, preoperative indocyanine green retention value at 15 minutes, tumor size, and number of tumor nodules were independent prognostic factors of long term survival, whereas the number of tumor nodules, tumor size, and venous permeation were the most powerful predictors of tumor recurrence. The cumulative 5-year survival rates for patients with Stages I, II, III, and IVA tumors were 72%, 55%, 34%, and 8%, respectively. Significant differences in cumulative survival curves were observed among the categories of pTNM classification. CONCLUSIONS: The results of this study showed that pTNM classification correlated well with postoperative survival. Preoperative evaluation of hepatic functional reserve with an indocyanine green clearance test plays an important role in determining the long term prognoses of patients with hepatocellular carcinoma.

Adolescent↗
PubMed1998

(+)-4-[2-[4-(8-Chloro-3,10-dibromo-6,11-dihydro-5H-benzo[5, 6]cyclohepta[1,2-b]- pyridin-11(R)-yl)-1-piperidinyl]-2-oxo-ethyl]-1-piperidinecarboxamid e (SCH-66336): a very potent farnesyl protein transferase inhibitor as a novel antitumor agent.

We have previously shown that appropriate modification of the benzocycloheptapyridine tricyclic ring system can provide potent farnesyl protein transferase (FPT) inhibitors with good cellular activity. Our laboratories have also established that incorporation of either pyridinylacetyl N-oxide or 4-N-carboxamidopiperidinylacetyl moieties results in pharmacokinetically stable inhibitors that are orally efficacious in nude mice. We now demonstrate that further elaboration of the tricyclic ring system by introducing a bromine atom at the 7- or the 10-position of the 3-bromo-8-chlorotricyclic ring system provides compounds that have superior potency and selectivity in FPT inhibition. These compounds have good serum levels and half-lives when given orally to rodents and primates. In vitro and in vivo evaluation of a panel of these inhibitors has led to identification of 15 (SCH 66336) as a highly potent (IC50 = 1.9 nM) antitumor agent that is currently undergoing human clinical trials.

Alkyl and Aryl Transferases↗
PubMed1998

Application of color Doppler flow mapping to calculate orifice area of St Jude mitral valve.

BACKGROUND: The effective orifice area (EOA) of a prosthetic valve is superior to transvalvular gradients as a measure of valve function, but measurement of mitral prosthesis EOA has not been reliable. METHODS AND RESULTS: In vitro flow across St Jude valves was calculated by hemispheric proximal isovelocity surface area (PISA) and segment-of-spheroid (SOS) methods. For steady and pulsatile conditions, PISA and SOS flows correlated with true flow, but SOS and not PISA underestimated flow. These principles were then used intraoperatively to calculate cardiac output and EOA of newly implanted St Jude mitral valves in 36 patients. Cardiac output by PISA agreed closely with thermodilution (r=0.91, Delta=-0.05+/-0.55 L/min), but SOS underestimated it (r=0.82, Delta=-1.33+/-0.73 L/min). Doppler EOAs correlated with Gorlin equation estimates (r=0.75 for PISA and r=0.68 for SOS, P<0.001) but were smaller than corresponding in vitro EOA estimates. CONCLUSIONS: Proximal flow convergence methods can calculate forward flow and estimate EOA of St Jude mitral valves, which may improve noninvasive assessment of prosthetic mitral valve obstruction.

Adult↗