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K K Ng

Publications and source records attributed to K K Ng.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy and safety of radiofrequency ablation for perivascular hepatocellular carcinoma without hepatic inflow occlusion.

BACKGROUND: The role of radiofrequency ablation (RFA) for perivascular (up to 5 mm from the major intrahepatic portal vein or hepatic vein branches) hepatocellular carcinoma (HCC) is unclear because of possible incomplete tumour ablation and potential vascular damage. This study aimed to evaluate the safety and efficacy of RFA for perivascular HCC without hepatic inflow occlusion. METHODS: Between May 2001 and November 2003, RFA using an internally cooled electrode was performed on 52 patients with perivascular HCC (group 1) through open (n = 39), percutaneous (n = 9), laparoscopic (n = 2) and thoracoscopic (n = 2) approaches. Hepatic inflow occlusion was not applied during the ablation procedure. The perioperative and postoperative outcomes were compared with those of 90 patients with non-perivascular HCC (group 2) treated by RFA during the same period. RESULTS: The morbidity rate was similar between groups 1 and 2 (25 versus 28 per cent; P = 0.844). One patient in group 1 (2 per cent) and two in group 2 (2 per cent) had developed thrombosis of major intrahepatic blood vessels on follow-up computed tomography scan. There were no significant differences between groups 1 and 2 in mortality rate (2 versus 0 per cent; P = 0.366), complete ablation rate for small HCC (92 versus 98 per cent; P = 0.197), local recurrence rate (11 versus 9 per cent; P = 0.762) and overall survival (1-year: 86 versus 87 per cent; 2-year: 75 versus 75 per cent; P = 0.741). CONCLUSION: RFA without hepatic inflow occlusion is a safe and effective treatment for perivascular HCC.

Adolescent↗
PubMed2005

Gallbladder cancer presenting with acute cholecystitis: a population-based study.

BACKGROUND: The role of laparoscopic cholecystectomy (LC) in acute cholecystitis remains controversial. The aim of the present study was to determine the incidence, clinicopathological characteristics, and outcome of patients with gallbladder cancer presenting with acute cholecystitis. METHODS: We performed a retrospective analysis of patients with gallbladder cancer who presented with acute cholecystitis and were treated at the public hospitals in Hong Kong between 1998 and 2002. RESULTS: Among 2,700 patients with acute cholecystitis managed with cholecystectomy (1,347 open and 1,353 LC), 63 patients (2.3%) were found to have gallbladder cancer. There were 44 women and 19 men with a mean age of 74.7 (+/-12.8) years. Adenocarcinoma (90.5%) was the most common cancer. The overall median survival was 5 months (95% CI = 2.6-7.4). The 5-year survival rate was 20.8%. Laparoscopic cholecystectomy was attempted in 11 patients and was completed successfully in six of them. There was no difference between the LC and open groups in the complication rate, hospital mortality rate, or survival rate. CONCLUSIONS: In the ethnic Chinese population of Hong Kong, the incidence of gallbladder cancer presenting with acute cholecystitis is higher than the same finding in patients undergoing elective cholecystectomy for cholelithiasis. Long-term survival is possible because such patients may be diagnosed at an early stage of the disease.

Acute Disease↗
PubMed2005

False-positive fluorine-18 fluorodeoxy-D-glucose positron emission tomography imaging caused by retained gauze in a woman with recurrent ovarian cancer: a case report.

We report a case of a 47-year-old woman with a false-positive [18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) result caused by retained gauze during resection of liver metastasis for a Stage IV ovarian cancer at primary cytoreductive surgery. She achieved complete remission and remained free of progression for seven years. Owing to elevation of CA-125, computed tomography and PET studies were performed, and both showed two potentially resectable lesions. One was located ventral to the diaphragmatic surface of the left hepatic lobe and the other was around the gauze at the right hepatorenal fossa. During surgical intervention, the left supraheptic tumor was excised and the gauze with surrounding granulation was removed. However, the former proved to be recurrent ovarian cancer with the latter proven false-positive. This case demonstrates that PET results should be interpreted with caution in differentiating a benign inflammatory process from malignant abnormalities, especially in regions with a high probability of granulomatous lesions.

Adenocarcinoma, Papillary↗
PubMed2005

Epidemiological study of diabetic retinopathy in a primary care setting in Hong Kong.

OBJECTIVES: To estimate the prevalence and risk factors of diabetic retinopathy in type 2 diabetic patients, and to investigate the difference in retinopathy progression in patients with normal fundi or established retinopathy at baseline and the risk factors implicated in the progression. DESIGN: Retrospective community-based study. SETTING: Ten primary care clinics in Hong Kong. PATIENTS: Type 2 diabetic patients; subsidiary analysis included subjects with more than one screening event. MAIN OUTCOME MEASURES: Patient demographics, baseline prevalence, and risk factors of diabetic retinopathy; progression of retinopathy in patients with normal fundi and established retinopathy at baseline, and the associated risk factors. RESULTS: A total of 6165 patients were recruited from January 1998 to May 2004. Primary analysis included 4423 patients with good-quality retinal photographs. The mean age of the patients was 60.36 years (standard deviation, 10.80 years; range, 28-94 years), the mean duration of diabetes was 4.71 years (standard deviation, 4.67 years; range, 0.1-40.6 years), and the mean level of glycated haemoglobin was 7.47% (standard deviation, 1.44%). The prevalence of retinopathy at baseline was 28.4%. Subsidiary analysis showed progression to sight-threatening retinopathy was more common in the group with baseline retinopathy than that without (7.9% vs 0.7%), and occurred at a faster rate (mean, 1.5 [range, 0.5-3.0] vs 2.0 [1.0-4.2] years). Logistic regression revealed that the level of glycated haemoglobin was positively associated with both the onset (P<0.001) and progression of retinopathy (P=0.03). CONCLUSION: Optimal glycaemic control is important for reducing sight-threatening retinopathy. Close observation is required for patients with established retinopathy as progression occurs more rapidly.

Adult↗
PubMed2004

Sperm output of older men.

BACKGROUND: Declining fertility of couples from the fourth decade of life is largely attributable to the drop in female fertility. However, increasing numbers of men, whose fertility theoretically lasts until death, are seeking fertility treatment at older ages, yet there is little information on sperm production and function past the age of 50 years. The few studies of such older men have examined men attending fertility clinics, and therefore willing to provide semen samples, but the participation bias of such recruitment hinders extrapolation to the unselected general male population. METHODS: We have taken the opportunity to study a convenience sample of 55 healthy, non-infertile men ranging in age from 52 to 79 years old who provided semen samples as part of a prostate cancer screening project. They were compared with a control group (n = 409) of younger (< 52 years) men from among 567 volunteers screened as potential sperm donors for an artificial insemination program. RESULTS: Older men had lower semen volume (mean semen volume 1.8 versus 3.2 ml; P < 0.0001) and total sperm output (median 74 versus 206 million sperm per ejaculate; P < 0.0001), whereas sperm density (median 64 versus 73 million sperm/ml; P = 0.12) was non-significantly decreased. Older men had more abnormal sperm morphology with decreasing numbers of normal forms (mean 14% versus 25%; P < 0.0001) and reduced vitality (mean 51% versus 80%; P < 0.0001), as well as increased numbers of cytoplasmic droplets (median 1 versus 0; P < 0.0001) and sperm tail abnormalities (30% versus 17%; P < 0.0001). Sperm head or neck abnormalities were no different between the groups. CONCLUSIONS: While neither study group may be representative of the general male population, these findings suggest that sperm production, reflected in sperm output but not sperm density, as well as sperm morphology and viability are diminished in this population of healthy, non-infertile older men.

Aged↗
PubMed2004

Role of CT-guided core needle biopsy in the diagnosis of a gossypiboma: case report.

A 66-year-old woman with previous hysterectomy had dysuria and vaginal spotting for 1 month. Computed tomography showed a heterogeneous presacral mass with eccentric calcification. Biopsies of the bladder and vagina and transrectal biopsy of the pelvic mass yielded only inflammation. T2-weighted magnetic resonance images revealed a heterogeneous mass with wavy hypointensities. Computed tomographically guided biopsy targeting at the calcified area disclosed thread-like materials, thus confirming the diagnosis of gossypiboma.

Aged↗
PubMed2004

Combined hepatocellular-cholangiocarcinoma: a case report.

Combined hepatocellular-cholangiocarcinoma (HCC-CC) is a rare primary liver tumour. We report a carrier of both HBV and HCV presenting with intermittent abdominal pain, fever, chillness and elevated á-fetoprotein (AFP) of 1197 ng/ml. Computed tomography showed an irregular hypodense mass in the left lateral segment of the liver with vague contrast enhancement and multiple regional lymphadenopathy. Hepatic angiogram showed that the mass was hypovascular and the left portal vein was occluded with a tapered end. Percutaneous ultrasound-guided core needle biopsy of the liver yielded HCC-CC. We suggest that HCC-CC should be considered in hypovascular liver tumours with striking elevation of serum AFP and multiple regional lymphadenopathy.

Adult↗
PubMed2004

Extracorporeal shockwave lithotripsy and intracorporeal lithotripsy for proximal ureteric calculi--a comparative assessment of efficacy and safety.

INTRODUCTION: Extracorporeal shockwave lithotripsy (ESWL) is the treatment modality of choice of many urologists for proximal ureteric calculi. In this study, we compared the efficacy and safety of ESWL versus ureteroscopy with holmium laser lithotripsy for the treatment of this group of stones. MATERIALS AND METHODS: Between May 1999 and October 2000, 50 patients had ESWL and another 51 patients underwent ureteroscopy with holmium laser lithotripsy for proximal ureteric calculi. The two groups were similar in age, sex ratio and stone size. ESWL was performed with the Dornier Compact lithotriptor whereas holmium laser lithotripsy was performed via retrograde ureteric access with a Wolf 7.5 Fr semirigid ureteroscope. RESULTS: Ureteroscopy with holmium laser lithotripsy was significantly better in terms of the mean procedure time (56 min in ESWL; 25 min in ureteroscopy; P < 0.001) and the 1-month stone free rate (50% in ESWL; 80% in ureteroscopy; P = 0.001). The 3-month stone free rate was also higher for ureteroscopy (78% in ESWL; 90% in ureteroscopy) but this difference was not statistically significant (P = 0.09). Minor complications of steinstrasse (6%) occurred in ESWL and proximal stone migration (8%) occurred during ureteroscopy. CONCLUSION: Ureteroscopy with holmium laser lithotripsy is a viable and safe alternative to ESWL for the management of proximal ureteric calculi.

Adult↗
PubMed2004

The prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting: cross-sectional study.

OBJECTIVES: To determine the prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting, and to study the association between various risk factors and the presence of microalbuminuria. DESIGN: Cross-sectional community-based study. SETTING: Four primary care clinics, Hong Kong. PATIENTS: All patients with type II diabetes mellitus who regularly attended the clinics between May 2002 and March 2003. MAIN OUTCOME MEASURES: Patients' demographic data, the proportion with microalbuminuria (measured using a spot urine test), and the association between this condition and risk factors for diabetic nephropathy (via correlation and multivariable logistic regression analysis). RESULTS: The mean age of the 1161 patients in the sample population was 58.0 years. The mean duration of diabetes mellitus was 5.7 years, and the mean level of glycated haemoglobin was 7.4%. A total of 13.4% of the patients had microalbuminuria. Having the condition was significantly associated with advanced age, female sex, poor glycaemic control, and coexisting hypertension in both correlation and regression analyses. No significant association with ever smoking was found. CONCLUSION: Early screening for incipient diabetic nephropathy and aggressive management of modifiable risk factors in a primary care setting may be important in optimising the renal outcome of patients with type II diabetes mellitus.

Adolescent↗
PubMed2003

Magnetic resonance imaging of hyaline cartilage regeneration in neocartilage graft implantation.

BACKGROUND: The purpose of this study was to investigate the regenerative potential of hyaline cartilage in a neocartilage graft implant with the aid of MR cartilage imaging using a rabbit model. METHODS: Surgical osteochondral defects were created in the femoral condyles of 30 mature New Zealand rabbits. The findings of neocartilage in autologous cartilage grafts packed into osteochondral defects were compared with control group of no implant to the osteochondral defect. The outcome of the implantations was correlated with histologic and MR cartilage imaging findings over a 3-month interval. RESULTS: Neocartilage grafts packed into osteochondral defects showed regeneration of hyaline cartilage at the outer layer of the implant using MR cartilage imaging. Fibrosis of fibrocartilage developed at the outer layer of the autologous cartilage graft together with an inflammatory reaction within the osteochondral defect. CONCLUSION: This animal study provides evidence of the regenerative ability of hyaline cartilage in neocartilage transplants to repair articular cartilage.

Animals↗
PubMed2002

Penile colour duplex ultrasonography as a screening tool for venogenic erectile dysfunction.

INTRODUCTION: Vasculogenic impotence is one of the major causes of erectile dysfunction. Cavernosometry and cavernosography is traditionally the gold standard for evaluation of venogenic impotence. However, it is invasive and there are potentially significant complications. Penile colour flow Doppler imaging (PCDI) is non-invasive and can be used to assess venous incompetence. MATERIALS AND METHODS: One hundred and sixty-eight patients were referred for PCDI assessment from March 1998 to February 2001. Forty-three of these also had cavernosogram and cavernosometry done and were included in the study. RESULTS: The sensitivity was 93.9%, the specificity was 90.0%, the accuracy was 93.0% with a negative predictive value of 81.8% and a positive predictive value of 96.9%. Kappa value of 0.81 was obtained, indicating excellent agreement between PCDI and cavernosogram and cavernometry. CONCLUSIONS: Penile colour flow Doppler imaging is accurate in the assessment of venogenic erectile dysfunction. It can replace cavernometry and cavernosogram as a screening tool. Cavernometry and cavernosogram should only be done in cases when PCDI suggests venogenic impotence, and when surgery is contemplated.

Adult↗
PubMed2002

The use of sildenafil in patients with erectile dysfunction in relation to diabetes mellitus--a study of 1,511 patients.

Erectile dysfunction (ED) seriously impairs the quality of life. Patients with diabetes mellitus (DM) are prone to ED due to various factors, including vasculopathy, neuropathy and sex hormone abnormalities. This is a retrospective study involving 1,511 patients taking sildenafil. Patients with DM have significantly more comorbidities like hypertension and ischaemic heart disease. They are also more likely to be on medications which may affect erectile function, including various antihypertensive drugs. 77.9% of patients with DM reported success with sildenafil, as compared to 86.5% of patients without DM. A significant number of patients with DM require a higher dose of sildenafil as compared to those without DM.

Diabetes Complications↗
PubMed2001

Crystal structure of gamma-chymotrypsin in complex with 7-hydroxycoumarin.

The 1.8 A crystal structure of 7-hydroxycoumarin (7-HC) bound to chymotrypsin reveals that this inhibitor forms a planar cinnamate acyl-enzyme complex. The phenyl ring of the bound inhibitor forms numerous van der Waals contacts in the S1 pocket of the enzyme, with the p-hydroxyl group donating a hydrogen bond to the main-chain oxygen atom of Ser217, and the o-hydroxyl group forming a water-mediated hydrogen bond with the carbonyl oxygen of Val227. The structure of the acyl-enzyme complex suggests that the mechanism of inhibition of 7-HC involves nucleophilic attack by the Ser195 O(gamma) atom on the carbonyl carbon atom of the inhibitor, accompanied by the breaking of the 2-pyrone ring of the inhibitor, and leading to the formation of a cinnamate acyl-enzyme derivative via a tetrahedral transition state. Comparisons with structures of photoreversible cinnamates bound to chymotrypsin reveal that although 7-HC interacts with the enzyme in a similar fashion, the binding of 7-HC to chymotrypsin takes place in a productive conformation in contrast to the photoreversible cinnamates. In summary, the 7-HC-chymotrypsin complex provides basic insight into the inhibition of chymotrypsin by natural coumarins and provides a structural basis for the design of more potent mechanism-based inhibitors against a wide range of biologically important chymotrypsin-like enzymes.

Animals↗
PubMed2001

Induction chemotherapy plus three-dimensional conformal radiation therapy in the definitive treatment of locally advanced non-small-cell lung cancer.

PURPOSE: To evaluate our institution's experience using chemotherapy in conjunction with three-dimensional conformal radiation therapy (3D-CRT). METHODS AND MATERIALS: From 1991 to 1998, 152 patients with Stage III non-small-cell lung cancer (NSCLC) were treated with 3D-CRT at Memorial Sloan-Kettering Cancer Center. A total of 137 patients (90%) were surgically staged with either thoracotomy or mediastinoscopy. The remainder were staged radiographically. Seventy patients were treated with radiation therapy alone, and 82 patients received induction chemotherapy before radiation. The majority of chemotherapy-treated patients received a platinum-containing regimen. Radiation was delivered with a 3D conformal technique using CT-based treatment planning. The median dose in the radiation alone group was 70.2 Gy, while in the combined modality group, it was 64.8 Gy. RESULTS: The median follow-up time was 30.5 months among survivors. Stage IIIB disease was present in 36 patients (51%) in the radiation-alone group and 57 patients (70%) in the combined-modality group. Thirty-nine patients had poor prognostic factors (KPS < 70 or weight loss > 5%), and they were equally distributed between the two groups. The median survival times for the radiation-alone and the combined-modality groups were 11.7 months and 18.1 months, respectively (p = 0.001). The 2-year rates of local control in the radiation-alone and combined-modality groups were 35.4% and 43.1%, respectively (p = 0.1). Grade 3 or worse nonhematologic toxicity occurred in 20% of the patients receiving radiation alone and in 16% of those receiving chemotherapy and radiation. Overall, there were only 4 cases of Grade 3 or worse esophagitis. CONCLUSION: Despite more Stage IIIB patients in the combined-modality group, the addition of chemotherapy to 3D-CRT produced a survival advantage over 3D-CRT alone in Stage III NSCLC without a concomitant increase in toxicity. Chemotherapy thus appears to be beneficial, even in patients who are receiving higher doses of radiation therapy than are typically given with conventional techniques. Because locoregional failure remains a major challenge in patients with advanced disease, 3D-CRT in conjunction with chemotherapy may allow safe treatment to the dose levels required to further enhance local control.

Adult↗
PubMed2001

Isolated paraaortic lymph node recurrence after definitive irradiation for cervical carcinoma.

PURPOSE: To evaluate the clinical features of isolated paraaortic lymph node (PALN) recurrence after definitive radiotherapy, and analyze the prognostic factors and effect of salvage treatment. METHODS AND MATERIALS: Of a total 876 patients who received pelvic radiotherapy after the diagnosis of primary cervical carcinoma, 26 were found to have isolated PALN recurrence as the first recurrent site, and these patients enrolled in this study. Only those with primary-site carcinoma controlled and who were free of other distant metastases were eligible. Nineteen of the 26 patients accepted salvage therapy. Fourteen patients accepted concurrent chemoradiation (CCRT), 1 accepted radiation to the paraaortic region, and 4 accepted chemotherapy alone. Clinical parameters evaluated included tumor markers (SCC and CEA) and image studies. RESULTS: Seven of the 26 patients were alive and disease-free. All 7 survivors had salvage treatment with radiation to the paraaortic region and concurrent cisplatin-based chemotherapy. None of the patients receiving chemotherapy or radiation alone enjoyed long-term, disease-free survival. The 5-year survival rate for isolated PALN recurrence of the 14 patients who accepted salvage concurrent chemoradiation (CCRT) was 51.2%. The presence of a clinical symptom at the time of PALN recurrence was analyzed. Seven of the 12 asymptomatic patients and none of the 14 symptomatic patients survived without disease after salvage treatment. The SCC levels at recurrence showed a statistically significant relationship to disease-free survival. CONCLUSIONS: An SCC level of < or = 4 ng/ml and a lack of symptoms at the time of recurrence were good prognostic factors in isolated PALN recurrence after primary radiation therapy. In addition to concurrent CCRT, periodical surveillance with tumor markers and imaging studies allowed early detection and salvage of those patients.

Adult↗
PubMed2001

X-ray crystallographic analyses of complexes between bovine beta-trypsin and Schiff base copper(II) or iron(III) chelates.

To establish the structural basis underlying the activity of a novel series of metal-chelate trypsin inhibitors, the structures of p-amidinosalicylidene-l-alaninato(aqua)copper(II) (1a), m-amidinosalicylidene-l-alaninato(aqua)copper(II) (1b), bis(p-amidinosalicylidene-l-alaninato)iron(III) (2a), and bis(m-amidinosalicylidene-l-alaninato)iron(III) (2b) bound to bovine beta-trypsin were studied by X-ray crystallography. The amidinium group of the inhibitor donates hydrogen bonds to Asp189, Gly219 and Ser190, as seen before in trypsin-benzamidine complexes. The copper(II) ion of 1a is situated away from trypsin's catalytic triad residues, and is octahedrally coordinated by a Schiff base and three water molecules. In contrast, the copper(II) ion of 1b is situated close to the catalytic triad and adopts a square pyramidal coordination geometry. The iron(III) ion of 2a is octahedrally coordinated by two Schiff base ligands and, like the copper(II) ion of 1a, is situated away from the catalytic triad. The p-amidinophenyl ring of a second Schiff base ligand of 2a is directed toward a hydrophobic groove formed by Trp215 and Leu99. Finally, the iron(III) ion of 2b appears to be replaced by magnesium(II), which is octahedrally coordinated by a Schiff base, Gln192 and two water molecules. One of the Schiff base ligands seen in the trypsin-2a complex or in the unbound form of 2b is replaced by water molecules and Gln192. His57 and Ser195 form water-mediated interactions with the magnesium(II) ion of 2b, and Ser195 also forms a hydrogen bond with the phenolic oxygen atom of the Schiff base ligand. These structures reveal a novel mode of interaction between metal-chelate inhibitors and serine proteases, thus providing a structural basis for the development of more potent inhibitors against a variety of trypsin-like enzymes.

Animals↗