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Biomedical subjects

J Wong

Publications and source records attributed to J Wong.

At least 19 recordsLinked to original sources

Living donor versus deceased donor liver transplantation for early irresectable hepatocellular carcinoma.

BACKGROUND: Hypothetical studies that favour living donor liver transplantation (LDLT) for early hepatocellular carcinoma (HCC) assumed a comparable outcome after LDLT and deceased donor liver transplantation (DDLT). The aim of this study was to compare the outcome after LDLT with that after DDLT, and to identify factors that might account for any differences. METHODS: The study included 60 patients who met the radiological Milan or University of California at San Francisco (UCSF) criteria and underwent LDLT (43 patients) or DDLT (17). RESULTS: The LDLT group had fewer incidental tumours and a lower rate of pretransplant transarterial chemoembolization but a higher rate of salvage transplantation. Waiting time was shorter and graft weight to standard liver weight (GW : SLW) ratio was lower in this group. The perioperative course, and histopathological tumour size, number, grade and stage were comparable. Median follow-up was 33 (range 4-120) months. The cumulative 5-year recurrence rate was 29 per cent in the LDLT group and 0 per cent in the DDLT group (P = 0.029). A GW : SLW ratio of 0.6 or less, salvage transplantation, three or more tumour nodules, microscopic vascular invasion, and pathological stage beyond the Milan or UCSF criteria were significant confounding risk factors. Multivariable analysis identified salvage transplantation (relative risk 5.16 (95 per cent confidence interval (c.i.) 1.48 to 18.02); P = 0.010) and pathological stage beyond the UCSF criteria (relative risk 4.10 (95 per cent c.i. 1.02 to 16.48); P = 0.047) as independent predictors of recurrence. CONCLUSION: Despite standard radiological selection criteria based on number and size, patients who underwent LDLT for HCC had more recurrence because of selection bias for other clinical characteristics.

Adolescent↗

Severely disordered esophageal peristalsis is not a contraindication to laparoscopic Nissen fundoplication.

BACKGROUND: Laparoscopic Nissen fundoplication (LNF) is the preferred operation for the control of gastroesophageal reflux disease (GERD). The use of a full fundoplication for patients with esophageal dysmotility is controversial. Although LNF is known to be superior to a partial wrap for patients with weak peristalsis, its efficacy for patients with severe dysmotility is unknown. We hypothesized that LNF is also acceptable for patients with severe esophageal dysmotility. METHODS: A multicenter retrospective review of consecutive patients with severe esophageal dysmotility who underwent an LNF was performed. Severe dysmotility was defined by manometry showing an esophageal amplitude of 30 mmHg or less and/or 70% or more nonperistaltic esophageal body contractions. RESULTS: In this study, 48 patients with severe esophageal dysmotility underwent LNF. All the patients presented with symptoms of GERD, and 19 (39%) had preoperative dysphagia. A total of 10 patients had impaired esophageal body contractions, whereas 32 patients had an abnormal esophageal amplitude, and 6 patients had both. The average abnormal esophageal amplitude was 24.9 +/- 5.2 mmHg (range, 6.0-30 mmHg). The mean percentage of nonperistaltic esophageal body contractions was 79.4% +/- 8.3% (range, 70-100%). There were no intraoperative complications and no conversions. Postoperatively, early dysphagia occurred in 35 patients (73%). Five patients were treated with esophageal dilation, which was successful in three cases. One patient required a reoperative fundoplication. Overall, persistent dysphagia was found in two patients (4.2%), including one patient with severe preoperative dysphagia, which improved postoperatively. Abnormal peristalsis and/or distal amplitude improved postoperatively in 12 (80%) of retested patients. There were no cases of Barrett's progression to dysplasia or carcinoma. During an average follow-up period of 25.4 months (range, 1-46 months), eight patients (16%) were receiving antireflux medications, with six of these showing normal esophageal pH study results. CONCLUSION: The LNF procedure provides low rates of reflux recurrence with little long-term postoperative dysphagia experienced by patients with severely disordered esophageal peristalsis. Effective fundoplication improved esophageal motility for most of the patients. A 360 degrees fundoplication should not be contraindicated for patients with severe esophageal dysmotility.

Contraindications↗

Major degradation product identified in several pharmaceutical formulations against the common cold.

Different pharmaceutical preparations against the common cold contain acetaminophen, phenylephrine hydrochloride, and chlorpheniramine maleate. A degradation product had been discovered in these preparations after short- and long-term stability studies. This degradation product was isolated and found to be an adduct of phenylephrine and maleic acid. An account of the isolation and characterization of this compound was published. Our interest in this area led us to synthesize the compound, and we found that the synthesized compound does not have the same spectroscopic properties described in the original paper. Our subsequent work identified the structure of the degradation product as a "Michael addition" product of phenylephrine and maleic acid.

Acetaminophen↗

Pharyngolaryngoesophagectomy using the thoracoscopic approach.

BACKGROUND: Thoracoscopic mobilization of the esophagus for pharyngolaryngoesophagectomy allows dissection under direct vision, and therefore it potentially results in fewer complications than conventional transhiatal mobilization. In this article we report our experience with this approach. It was also hypothesized that a learning curve existed and that results have improved over time. PATIENTS AND METHODS: From July 1994 until January 2004, 57 patients underwent pharyngolaryngoesophagectomy in our institution. Intraoperative events and postoperative outcome were prospectively documented, and long-term follow-up data were also studied. Results were compared between the first 30 patients and the last 27 patients. RESULTS: There were no significant differences between the two groups with respect to the various clinicopathological characteristics. There was no difference in the median thoracoscopic time between the first 30 and last 27 patients at 90 and 75 min, respectively, p = 0.18. For the complete procedure there was significantly less blood loss in the later group; median (range) blood loss 700 (164-3000) ml versus 400 (100-1200) ml, p = 0.002. Overall pulmonary complications occurred in 12 patients (40%) in the first group versus 13 (48%) in the second group, p = 0.6. The incidence of atrial arrhythmia was also similar, affecting 6 (20%) patients and 3 (11%), respectively, p = 0.47. Hospital mortality rates were 13.3% and 7.4%, p = 0.67. Two-year survival rates were no different (46% versus 45% p = 0.85). CONCLUSIONS: Although, subjectively, operating skills have improved over time, better results in the second half of this series could not be demonstrated clearly, likely because the operating surgeons had prior extensive experience in esophageal and thoracoscopic procedures.

Adult↗

Temporal changes in cerebral tissue oxygenation with cerebrovascular pressure reactivity in severe traumatic brain injury.

OBJECTIVE: To investigate the temporal relationship between cerebrovascular pressure reactivity and brain tissue oxygenation in patients with severe head injury. METHODS: In 40 patients, brain tissue oxygenation and intracranial pressure were monitored. Time-averaged values for intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP) and brain tissue oxygenation (PtiO2) were computed. The pressure reactivity index (PRx) was calculated. The mean values of the variables were obtained at the 6-h and 72-h post-injury time points, and the difference between the two time points for each of the variables was denoted as delta (delta). RESULTS: Of the 40 patients, 32 were survivors and 8 were non-survivors. Statistically significant differences were present between these two groups with regard to deltaMAP (p = 0.013), ICP at 6 h (p = 0.027), CPP at 72 h (p = 0.018), deltaCPP (p = 0.033), PRx at 6 h (p = 0.029), PRx at 72 h (p = 0.002), PtiO2 at 72 h (p < 0.0005) and deltaPtiO2 (p = 0.023) values, reflecting an improvement with time in survivors and a deterioration with time in non-survivors. In non-survivors, the magnitude of change in PtiO2 and CPP with time correlated in a negative linear fashion (p = 0.042 and 0.029, respectively) with the change in PRx with time, whereas no such relationship was seen in survivors. CONCLUSION: The severity of brain tissue oxygenation derangement correlates with increasing cerebrovascular dysautoregulation in patients succumbing to severe head injury, supporting the utility of PRx as a monitoring variable and the rationale for a target-driven approach to head injury management.

Adult↗

In vivo tracking of macrophage activated killer cells to sites of metastatic ovarian carcinoma.

Radio-labelling of blood cells is an established technique for evaluating in vivo migration of normal cells to sites of pathology such as infection and haemorrhage. A limitation of cellular immunotherapies to induce anti-tumour responses is in part due to the uncertain ability of cellular effectors to reach their intended target. We extended the approach of cell radiolabelling to accurately examine the in vivo distribution of cellular immunotherapy with ex-vivo macrophage activated killer (MAK) cells. We describe the use of two methods of cell labelling for tracking the destination of autologous-derived macrophage activated killer (MAK) cells linked to the bi-specific antibody MDX-H210 delivered either by intravenous (i.v.) or intraperitoneal (i.p.) injection in ten patients with peritoneal relapse of epithelial ovarian carcinoma. Our results demonstrate the feasibility of generating high numbers and purity of GMP quality MAK cells, which can be radiolabelled with (18)F-FDG or (111)In-oxime. MAK cell administration produced minimal infusional toxicity and demonstrated a reproducible pattern of in vivo distribution and active in vivo tracking to sites of known tumour following 8 of 16 i.v. infusions or 4 of 6 i.p. infusions. However, the leakage of (18)F-FDG limited the ability to confidently confirm the tracking of MAK cells to tumour in all cases and improved PET labels are required. The addition of MDX-H210 bispecific antibody did not alter the distribution of cells to tumour sites, but did accelerate the clearance of i.v. administered MAK cells from the pulmonary circulation. This data demonstrates that cellular cancer immunotherapies may be successfully delivered to the sites of active tumour following either i.v. or i.p. injection in a proportion of patients with metastatic cancer. Incorporation of tracking studies in early cycles of cellular immunotherapy may allow selection of patients who demonstrate successful targeting of the immunotherapy for ongoing treatment.

Antibodies, Bispecific↗

The impact of various rehydration volumes for firefighters wearing protective clothing in warm environments.

This study examined different fluid replacement quantities during intermittent work while wearing firefighting protective clothing and self-contained breathing apparatus in the heat (35 degrees C, 50% relative humidity). Twelve firefighters walked at 4.5 km per h with 0% elevation on an intermittent work (50 min) and rest (30 min) schedule until they reached a rectal temperature of 39.5 degrees C during work periods and 40.0 degrees C during rest, heart rates of 95% of maximum and/or exhaustion. During the heat-stress trials subjects received one of four fluid replacement quantities, high (H), moderate (M), low (L), and no hydration (NH), where H, M and L represented 78%, 63% and 37% of fluid loss, respectively. The total tolerance time (work + rest) was significantly greater during H (111.8 +/- 3.5), M (112.9 +/- 5.2) and L (104.2 +/- 5.8) compared to NH (95.3 +/- 3.8). In addition, work time (min), which excluded rest periods, was significantly greater in H (82.6 +/- 3.5), and M (82.9 +/- 5.2) compared to NH (65.3 +/- 3.8). It is concluded that incorporating even partial fluid replacement strategies while wearing firefighting protective clothing and self-contained breathing apparatus in the heat improves tolerance time.

Fires↗

Decreased intranuclear mobility of acute myeloid leukemia 1-containing fusion proteins is accompanied by reduced mobility and compartmentalization of core binding factor beta.

Acute myeloid leukemia 1 (AML1) gene on chromosome 21 is involved in several chromosomal translocations, including t(8;21) and t(16;21), that produce chimeric fusion proteins AML1-eight twenty-one (ETO) and AML-myeloid transforming gene chromosome 16 (MTG16), which contribute to leukemogenesis. The molecular basis for the leukemogenic effects of these fusion proteins is incompletely understood. Using gel-shift assay, we showed that AML1-ETO and AML1-MTG16 bound to a series of AML1 consensus DNA-binding sites with different affinities. Using fluorescence recovery after photobleaching (FRAP), we demonstrated that a fusion of AML1 with ETO or MTG16 exhibits reduced intranuclear mobility compared with wild-type AML1 or either fusion partner. The dimerization domain (nervy homology region 2) of ETO is responsible for the reduced mobility of AML1-ETO. Dual FRAP studies revealed that CBFbeta colocalized with AML1-ETO within the nucleus, resulting in reduced mobility of CBFbeta. Therefore, AML1 fusion proteins may interfere with normal AML1 function due to aberrant nuclear dynamics, which leads to spatial and temporal sequestration of CBFbeta and perhaps other coregulators critical for myeloid differentiation.

Animals↗

Improved operative and survival outcomes of surgical treatment for hilar cholangiocarcinoma.

BACKGROUND: The aim of the present study was to assess whether an aggressive surgical approach in the management of patients with hilar cholangiocarcinoma was associated with improved operative and survival outcomes. METHODS: Eighty-two patients with hilar cholangiocarcinoma treated between 1989 and 1998 (period 1), and 60 patients treated between 1999 and 2004 (period 2), were evaluated. Modifications to management in period 2 primarily included percutaneous biliary drainage instead of endoscopic drainage for relief of obstructive jaundice, preoperative right portal vein embolization before right-sided hepatectomy, routine total caudate lobectomy and radical lymphadenectomy during surgical resection of the tumour. RESULTS: The surgical resection rate was significantly higher in period 2 than in period 1 (45 versus 16 per cent; P < 0.001). All patients in period 2 underwent major hepatectomy with concomitant caudate lobectomy. The operative morbidity and hospital mortality rates decreased significantly in period 2 compared with period 1, with significantly better survival outcomes. In multivariate analysis, resection of the tumour in period 2 and operative blood loss of 1.5 litres or less were the significant independent factors associated with improved survival. CONCLUSION: An aggressive surgical approach was associated with improved operative and survival outcomes for patients with hilar cholangiocarcinoma.

Aged↗

Characterization of cerebrovascular reactivity after craniectomy for acute brain injury.

Analysis of slow waves in arterial blood pressure (ABP) and intracranial pressure (ICP) has been used as an index to describe cerebrovascular pressure-reactivity. It has been previously demonstrated that the pressure-reactivity index (PRx) can be used to reflect global cerebrovascular reactivity with changes in ABP. A positive PRx signifies a positive association between ABP and ICP, indicating a non-reactive vascular bed, while a negative PRx is reflective of intact cerebral autoregulation, where ABP waves provoke inversely correlated waves in ICP. To date, there has been no characterization of pressure-reactivity following decompressive craniectomy. In this prospective observational study, 33 patients who underwent surgery for acute brain injury with mass lesions for which the bone flap was left out were studied. The PRx was calculated as a moving correlation coefficient between 30 consecutive samples of values of ICP and ABP averaged for a period of 10 s. The time profiles of mean PRx values at 6-hourly intervals were analysed and compared with that in seven patients treated by medical therapy alone. The initial mean PRx 6 h after surgery was positive, indicative of disturbed pressure-reactivity. With time, PRx trended towards a more negative value, suggestive of an improving cerebrovascular autoregulatory reserve. The mean PRx 24 h after surgery was 0.28 (+/-0.26), while the mean PRx 72 h after surgery was 0.15 (+/-0.25) (p = 0.012). In contrast, the mean PRx in patients that were not decompressed did not change significantly with time (p = 0.357). Surgery in acute brain injury for which the bone flap is left out in anticipation of raised intracranial pressure in the postoperative period leads to an improved PRx as compared with controls. Craniectomy in this situation may have a contribution to the restoration of disturbed cerebrovascular pressure-reactivity.

Adult↗

Central neurocytoma in third and fourth ventricles with aqueductal involvement.

Central neurocytomas are characterized by their intraventricular locations, usually arising from the lateral ventricles and their benign clinical course. Variations in location, histology and clinical behaviour have been reported in recent years. The authors present two cases of central neurocytomas arising in the third and fourth ventricles with aqueductal involvement. The atypical features in their location and behaviour are discussed. The cases represent the extended spectrum of central neurocytomas.

Adult↗

Esophageal hematoma.

Hematoma of the esophagus is an uncommon condition. Patients often present with acute odynophagia or retrosternal pain, which may be confused with other diagnoses. We report herein two patients with esophageal hematoma caused by foreign body ingestion. Conservative treatment resulted in complete resolution. The literature is reviewed for the etiology, clinical features and management of this condition.

Aged↗

The metabolic syndrome in type 2 diabetes: When does it matter?

AIMS: Young adults with type 2 diabetes (T2Dm) present the clinician with the problem of when to start therapies for the primary prevention of vascular disease and how to identify those at most vascular risk. We examine whether the metabolic syndrome (MetS) can be a useful clinical tool to stratify vascular risk in this context. METHODS: Data were collected from 5928 subjects with T2Dm, and subjects were categorized as having MetS by World Health Organization criteria (body mass index criteria modified for Asians using >23 kg/m2). The prevalence of macrovascular disease was examined by MetS status and age. RESULTS: The overall MetS prevalence was 72.3%. MetS was associated with an increased prevalence of ischaemic heart disease (IHD) (17.2% MetS vs. 11.6% no MetS, p < 0.0001), coronary artery bypass graft (7.6 vs. 4.7%, p < 0.0003), peripheral vascular disease (PVD) (4.7 vs. 3.7%, p = 0.08) and stroke (6 vs. 3.9%, p = 0.002) across all age groups. MetS subjects had an IHD prevalence equivalent to that seen in subjects who were one decade older without MetS. The most significant impact of MetS was for the age group of 40-49 years with much lesser impact seen with progressively increasing age [odds ratio (OR) = 2.1 for IHD in MetS compared with no MetS at age 40-50 years, p < 0.05; falling progressively to OR = 1.5 at age >70 years, p > 0.05]. Similar trends were seen for coronary artery by-pass graft (CABG) and PVD. There was a strong relationship between the number of MetS risk factors and IHD prevalence (r = 0.99, p = 0.0001). CONCLUSIONS: These data suggest that MetS is particularly useful in stratifying vascular risk in younger T2Dm patients and in those with a high number of MetS components. For patients with MetS, especially those with a full house of MetS risk factors, commencing risk-lowering interventions 10 years earlier than their MetS-free counterparts could be considered.

Adult↗

An evaluation of emergency medicine investigators' views on open access to medical literature.

BACKGROUND: Scientists and governmental agencies have called for free universal access to research publications via the internet--open access. OBJECTIVES: To examine the current medical literature reading practices of emergency medicine investigators (EMIs) and their views towards open access. METHODS: Surveys were mailed to the 212 corresponding authors of all original research articles published in years 2002 and 2003 in the Annals of Emergency Medicine, Academic Emergency Medicine and The Journal of Emergency Medicine. RESULTS: The most commonly read forms of medical literature reported by the 129 (61%) EMI respondents were hard-copy medical journals and online literature review services. 59% of EMIs were in favour of open access; 58% stated they would read a wider variety of medical literature; 21% believed open access would improve the quality of publications and 39% thought it would decrease the quality. When asked how a US 1500 dollars fee for open access would affect their ability to publish research, 69% said it would greatly impede and 19% said it would slightly impede their research. CONCLUSIONS: Despite concerns that open access may impede their ability to publish research and decrease the quality of publications, most EMIs surveyed favoured open access. They believed open access would increase and broaden their medical literature reading.

Adult↗

Clinical relevance of Fas expression in oesophageal squamous cell carcinoma.

AIMS: To determine the extent of Fas expression in oesophageal squamous cell carcinomas (ESCCs) from Chinese patients and to correlate Fas expression with clinicopathological prognostic parameters. METHODS: Clinicopathological data were collected from 58 patients with ESCC who underwent oesophagectomy and had no prior radiotherapy or chemotherapy. Immunostaining was performed on the primary tumours. Expression of Fas was correlated with patients' demographics, tumour characteristics and stage, R category of surgery, and patients' survival. RESULTS: The actuarial survival rates of all patients at two and five years after surgery were 48% and 14%, respectively. Fas expression was detected in 89.7% of ESCCs. Higher Fas expression recorded on a four point scale correlated with better tumour differentiation (p < 0.01), but not with other patient or tumour variables. Importantly, higher Fas expression was associated with better survival (p = 0.0317). CONCLUSIONS: These findings suggest that Fas activated apoptosis is important in the pathogenesis of ESCC. This molecular pathway may be a potential therapeutic target for ESCC.

Adult↗

Cardiovascular complications of severe acute respiratory syndrome.

BACKGROUND AND AIMS: Severe acute respiratory syndrome (SARS) is a virulent viral infection that affects a number of organs and systems. This study examined if SARS may result in cardiovascular complications. METHODS AND RESULTS: 121 patients (37.5 (SD13.2) years, 36% male) diagnosed to have SARS were assessed continuously for blood pressure, pulse, and temperature during their stay in hospital. Hypotension occurred in 61 (50.4%) patients in hospital, and was found in 28.1%, 21.5%, and 14.8% of patients during the first, second, and third week, respectively. Only one patient who had transient echocardiographic evidence of impaired left ventricular systolic function required temporary inotropic support. Tachycardia was present in 87 (71.9%) patients, and was found in 62.8%, 45.4%, and 35.5% of patients from the first to third week. It occurred independent of hypotension, and could not be explained by the presence of fever. Tachycardia was also present in 38.8% of patients at follow up. Bradycardia only occurred in 18 (14.9%) patients as a transient event. Reversible cardiomegaly was reported in 13 (10.7%) patients, but without clinical evidence of heart failure. Transient atrial fibrillation was present in one patient. Corticosteroid therapy was weakly associated with tachycardia during the second (chi(2) = 3.99, p = 0.046) and third week (chi(2) = 6.53, p = 0.01), although it could not explain tachycardia during follow up. CONCLUSIONS: In patients with SARS, cardiovascular complications including hypotension and tachycardia were common but usually self limiting. Bradycardia and cardiomegaly were less common, while cardiac arrhythmia was rare. However, only tachycardia persisted even when corticosteroid therapy was withdrawn.

Blood Pressure↗