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Biomedical subjects

J Wong

Publications and source records attributed to J Wong.

At least 505 records · Page 28Linked to original sources
PubMed1991

Comparison of a single layer continuous hand-sewn method and circular stapling in 580 oesophageal anastomoses.

A total of 611 patients with carcinoma of the oesophagus or gastric cardia were operated on between July 1982 and December 1989. Resection was performed in 491 patients (one-stage, 483; two-stage, eight), bypass operation in 97, and 23 had exploration alone. The anastomoses of 580 patients with one-stage resection and bypass operations were evaluated. Hand-sewn anastomosis using a single layer of continuous absorbable monofilament suture was performed in 304 patients (221 resections and 83 bypasses). A stapled anastomosis was performed on 276 patients (262 resections and 14 bypasses). Following resection, there were 11 (5 per cent) anastomotic leaks in the hand-sewn group and ten (3.8 per cent) in the stapled anastomosis group (P = 0.69). Excluding anastomotic leaks, hospital mortality and anastomotic recurrence, stricture occurred in 18 of 172 hand-sewn anastomoses (10.5 per cent) and in 57 of 195 stapled anastomoses (29.2 per cent) (P less than 0.001). In patients who had bypass operations there were 12 anastomotic leaks, ten in the hand-sewn group (12.0 per cent) and two in the stapled anastomosis group (14.3 per cent). Only two of the discharged patients with bypass developed anastomotic strictures, a low incidence probably because of short survival. In addition, there were 245 subsidiary anastomoses made in the abdomen by the hand-sewn method as part of the reconstructive procedure, and there was one leak. The results of this non-randomized study suggest that hand-sewn anastomosis using a single layer continuous technique for the oesophagus is as safe as the use of circular staplers; hand-sewn anastomosis is less likely to become stenotic.

Anastomosis, Surgical↗
PubMed1991

Pyloroplasty versus no drainage in gastric replacement of the esophagus.

In a prospective randomized study of pyloroplasty versus no drainage, 200 patients (100 in each group) in whom the whole stomach was used for reconstruction following resection for esophageal carcinoma were studied. Only patients who underwent the Lewis-Tanner operation and who had a normal pylorus were included. There was no morbidity from the pyloroplasty procedure. Thirteen patients without drainage developed symptoms of gastric outlet obstruction, requiring prolonged post-operative parenteral nutrition, and reoperation was required in one patient. Four patients developed pulmonary complications associated with gastric distension, which resulted in fatal aspiration in two patients. Five patients had symptoms of outlet obstruction with eating at the time of their death. Mean and standard deviation of daily gastric aspirate was 161 +/- 88 mL in the pyloroplasty group and 233 +/- 142 mL for the control group (p = 0.23). Gastric emptying test showed mean T1/2 +/- standard deviation of 6.6 +/- 7.5 minutes in the pyloroplasty group and 24.3 +/- 31.5 minutes in the control group (p less than 0.001). More patients in the pyloroplasty group were able to tolerate a solid diet and at normal or increased amounts than were patients in the control group in the early postoperative weeks (p less than 0.01). In addition, control patients were found to have increased symptoms with meals, which were more frequent and of greater severity than symptoms in patients in the pyloroplasty group, even at 6 months after surgery (p less than 0.01). Therefore, we recommend a pyloroplasty for patients in whom the whole stomach is used for reconstruction after esophagectomy.

Deglutition↗
PubMed1991

Relationship between adenylate cyclase activity and regional myocardial energetics in experimental left ventricular hypertrophy.

The aim of this study was to examine the responsiveness of the hypertrophied left ventricle to beta-adrenergic stimulation in a pressure overload model produced by valvular aortic stenosis and characterized by reduced beta-adrenoceptor number. The study was designed to correlate changes in global and regional cardiac work and energetics in response to isoproterenol with adenylate cyclase activity. Eleven anesthetized dogs with left ventricular hypertrophy and 11 controls were studied at rest and during 0.5 and 1.0 micrograms/kg/min isoproterenol infusion. We measured regional work from segment length and force changes with ultrasonic dimension crystals and miniature force gauges in addition to arterial and left ventricular blood pressure and cardiac output. Regional myocardial oxygen consumption was calculated from O2 extraction using microspectrophotometry and blood flow using radioactively labeled microspheres. Adenylate cyclase activity was assayed at baseline and after stimulation with forskolin. Isoproterenol significantly increased heart rate, dP/dtmax, cardiac output, and external work to similar levels in control and hypertrophied animals. Similarly, regional work increased from 463 +/- 115 to 995 +/- 584 g x mm/min for controls and from 392 +/- 156 to 1175 +/- 577 for hypertrophied dogs with high dose isoproterenol. Regional O2 consumption also increased to similar levels (20.3 +/- 14.7 vs 16.2 +/- 6.3 ml O2/min/100 g) in both groups. Adenylate cyclase activity was lower in hypertrophy at baseline (23.9 +/- 7.3 vs 62.9 +/- 14.2 pM/min/mg protein for controls), but was the same as for controls with forskolin stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1991

Trauma to elbows, knees, and ankles.

In summary, the emergency department or office-based physician should distinguish first between inflammation and injury. A clinical diagnosis of fracture should be made before obtaining and reading films. Comparison views help to resolve doubt. A neurologic examination should be documented before undertaking reduction. Finally, if in doubt, a splint for 24 to 48 hours until an orthopedic opinion is available causes no harm.

Ankle Injuries↗
PubMed1991

Peri-operative mortality in hepatic resection.

The operative results of hepatic resections (n = 67) during the past 28 months are reported. Major hepatic resection (lobectomy, extended lobectomy) was performed in 78% of patients with hepatocellular carcinoma (HCC) and in 24% of patients with non-HCC diseases. The overall operative mortality was 10%: 15% for HCC and 0% for non-HCC diseases. The operative mortality in the HCC group occurred exclusively in patients who had undergone right or extended right lobectomy. The operative mortality of right or extended right lobectomy in patients with HCC increased considerably with the presence of cirrhosis (32% vs 0%) and a liver function worse than Child's A (60% vs 17%). In HCC, the incidence of operative mortality (47%) and postoperative hepatic failure (73%) was higher when there had been massive operative blood loss (greater than or equal to 4.0 L) and/or persistent postoperative haemorrhage, compared with 0% and 24% respectively in cases without massive peri-operative bleeding. While postoperative hepatic failure was present in 5 of 7 fatalities, it was not an independent prognostic factor, but was dependent on the presence of massive peri-operative blood loss.

Adolescent↗
PubMed1991

A case of early carcinoma of the oesophagus in association with annular pancreas.

A Chinese patient presented with a 3-week history of vomiting. Pre-operative barium swallow and upper endoscopy and biopsy revealed a squamous cell carcinoma of the lower oesophagus. Operative findings included a relatively early carcinoma of the oesophagus and an annular pancreas with dilated proximal duodenum. Oesophagectomy was performed and the whole stomach used for reconstruction. A pylorojejunostomy provided drainage for the stomach as well as decompression of the proximal duodenum. This patient's congenital anomaly, with its attendant symptoms, led to the early diagnosis and treatment of an oesophageal malignancy with an expected improved prognosis.

Aged↗
PubMed1991

A mandibular block technique useful in 'gaggers'.

Three patients with severe gagging problems requiring mandibular molar extractions and who could not tolerate conventional block injections were successfully given closed-mouth mandibular block injections without provoking any retching. This technique permits patients to concentrate on clenching their teeth during the injection. This displacement activity, combined with the reduction in tactile sensation following anaesthesia, helps to prevent gagging.

Adult↗
PubMed1991

Hydroxyapatite cement based drug delivery systems: drug release in vitro.

A novel approach using a self-setting hydroxyapatite (HAP) cement as a skeletal drug delivery system has been proposed to solve the problem of delivering drugs to skeletal tissue at high local concentrations for desirable therapeutic effects. Hydroxyapatite cements loaded with antibiotics can be formed in situ and can be used as bonding materials between bone and prostheses as well as for drug release devices. The cement also possesses sufficient mechanical strength to be a potential bone grafting material. Using cephalexin and norfloxacin as model drugs, the continuous in vitro release profiles of these compounds from 0.9-4.8% by weight loaded cement pellets were observed. These drug release patterns correlated well with the Higuchi model. This hydroxyapatite cement drug delivery system can be applied in the treatment of osteomyelitis and infected compound fractures.

Bone Cements↗
PubMed1991

NGF rescues substance P expression but not neurofilament or tubulin gene expression in axotomized sensory neurons.

A reduction in the supply of retrogradely transported NGF has been proposed as a possible signal for the axotomy response in dorsal root ganglion (DRG) neurons. Components of the axotomy response that have previously been well characterized in axotomized DRG cells include changes in cytoskeletal gene expression and changes in the expression of neurotransmitters/neuromodulators such as substance P. In this study, we examined the role of NGF in the axotomy response by examining protein synthesis and mRNA levels of the low-MW neurofilament protein (NF-L) and beta-tubulin in DRG cells at 1, 7, and 12 d after axotomy with and without continuous administration of exogenous NGF. We also examined substance P levels in the DRG by immunocytochemistry under the same experimental conditions. Sciatic nerves of adult male rats were unilaterally transected at the midthigh level, and the proximal nerve stumps were placed into Silastic tubes connected to osmotic minipumps that were filled with biologically active NGF. NGF (0.5 mg/ml in saline) was continuously infused (0.5 microliter/hr) onto the proximal stumps of transected sciatic nerves for 1-12 d. Control animals were prepared in an identical fashion except that the nerves were treated with saline alone. At death, DRGs were removed from the animals; the L4 experimental DRGs (axotomized) and contralateral L4 DRGs (uninjured) were used immediately for protein synthesis experiments, while the experimental and contralateral L5 DRGs were fixed in 4% paraformaldehyde and subsequently used for in situ hybridization and immunocytochemistry. From another set of experimental animals, the L4 and L5 DRGs were harvested and used for total RNA isolation and RNA blotting experiments. Immunocytochemical studies using a polyclonal antibody to substance P showed that the immunodetectable levels of this peptide decreased to undetectable levels in DRG neurons after axotomy and saline administration. However, in axotomized neurons treated with NGF, the level of immunodetectable substance P did not decrease, but instead, increased over even that present in normal DRG neurons. Pulse labeling of DRGs with 35S-methionine:cysteine followed by 2-dimensional (2D) gel electrophoresis and fluorography revealed that the synthesis of neurofilament (NF) proteins was decreased, while that of tubulin was increased, 12 d after sciatic nerve transection. NGF administration to axotomized neurons did not alter this pattern. Quantitative analysis of in situ hybridizations of DRG neurons and RNA blot analysis with cDNA probes specific for NF-L and beta-tubulin mRNAs showed that NGF treatment of axotomized DRGs did not significantly affect cytoskeletal gene expression at the mRNA level.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Tau gene expression in rat sensory neurons during development and regeneration.

In the mature rat dorsal root ganglion (DRG), only one tau isoform is expressed, and this protein (110 kDa in apparent molecular weight) is considerably larger in size than the predominant tau isoforms found in brain. The size of the mRNA encoding the "big" tau mRNA in DRG [approximately 8 kilobases (kb)] is also much larger than that of the major rat brain tau mRNA species (approximately 6 kb). In this study, we examined the pattern of normal developmental changes in expression of this high-molecular-weight (HMW) tau and its encoding mRNA and also determined how axonal injury of adult DRG neurons effected the expression of this gene. RNA blotting experiments revealed that higher levels of HMW tau mRNA were present in the DRG at early postnatal times than in the adult. Immunoblotting of total DRG protein using a monoclonal tau antibody revealed that the immature DRG (7 d postnatal) contained a 62-kDa tau isoform in addition to the HMW tau isoform that was expressed in the adult DRG. Neither of the tau isoforms expressed in the immature DRG was present to any significant extent in either immature or adult rat brain. To examine how tau expression changed in adult DRG neurons during regeneration, the sciatic nerves of rats were unilaterally crushed, and the L4 and L5 DRG were harvested 1, 7, and 14 d later.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

A modified reaction cartridge for direct protein sequencing on polymeric membranes.

A newly designed reaction vessel implements a vertical cross-flow type reactor with the Applied Biosystems multi-mode reaction cartridge design. This cartridge is designed for sequencing samples on polyvinylidine difluoride-type membranes. The benefits of this design include a reduced reaction chamber volume that results in lower rates of chemical consumption and less risk of sample loss or contamination during sequencing. Visualization of the membrane in the reaction chamber during sequencing facilitates optimization of drying, washing, extraction and transfer times. The cycle modifications described in this report are designed to optimize post-coupling extraction, cleavage and post-cleavage extraction steps during "flow across" conditions for polymeric membranes. Also, efficient washing and drying of membranes allows for a fast cycle time of 30 minutes when using Pulsed Liquid chemistry. Examples of Blott cartridge utility for sequencing polyvinylidine difluoride-bound proteins in the low picomole range are shown by analyzing samples prepared by a two-dimensional purification scheme using the 230A HPEC and sodium dodecyl sulfate polyacrylamide gel electrophoresis.

Amino Acid Sequence↗
PubMed1991

Ossicular erosion by cholesteatoma: investigation by scanning electron microscopy utilizing a new preparation technique.

A new technique for removing the soft tissues from middle ear ossicles to prepare them for scanning electron microscopy is described. The technique involved use of a solution of hypochlorite. The bony surface of normal ossicles was studied as a control group after preparation by the technique and no morphological distortion was observed. Ossicles eroded by cholesteatoma were then studied, and we propose that the erosion occurs in three stages; pumicing, pitting and cavitating. The mucoperiosteum of normal ossicles and otosclerotic foci were also studied.

Cholesteatoma↗
PubMed1991

Carcinoma of the gallbladder: a diagnostic challenge.

Since the introduction and availability of abdominal ultrasound and computed tomography, 38 patients have been admitted to the Department of Surgery, Queen Mary Hospital, University of Hong Kong with a subsequently confirmed histological diagnosis of carcinoma of the gallbladder. The majority of patients presented with abdominal pain, anorexia or weight loss, jaundice, and anaemia or an abdominal swelling. Abnormal liver function tests were found in 70-90%. Cholangiography, ultrasound and particularly computed tomography helped to confirm clinical suspicion when performed but 23 patients (61%) had an inaccurate diagnosis made before surgery. Operative intervention was only of benefit when the carcinoma was confined to the gallbladder (median survival after cholecystectomy alone 13 months; other procedures 2 months; P less than 0.01). Carcinoma of the gallbladder carries a poor prognosis but ultrasound and computed tomography can help select patients for appropriate treatment (surgery, endoscopic stenting, radiotherapy, chemotherapy) if clinical suspicion is raised.

Adult↗
PubMed1991

Treatment of hepatolithiasis: improvement of result by a systematic approach.

In previous decades the result of treatment of hepatolithiasis has been unsatisfactory. The incidence of residual stones after surgery might reach 77%. In the past 6 years we adopted a systematic approach comprised of accurate delineation of disease in the liver and biliary tract by direct cholangiography, ultrasonography, and computed tomography; tailored surgical treatment according to the extent of involvement of the liver and biliary tract; access to the intrahepatic ducts through the left duct or round ligament approach when there was difficulty with common bile duct exposure; routine use of flexible choledochoscopy; and application of electrohydraulic lithotripsy for large and impacted stones. Complete stone clearance was achieved in 114 of 127 patients (89.8%). Of those patients who had incomplete stone clearance, only six cases (4.7%) were related to technical failure of postoperative choledochoscopy. The incidence of stone recurrence was 15.8%, the lowest rate so far reported. It was the same regardless of whether a biliary drainage procedure had been performed, but the treatment for recurrent stones was facilitated by previous hepaticocutaneous jejunostomy. Overall the surgical treatment required for stone recurrence was of a lesser magnitude than that in the past.

Adolescent↗
PubMed1991

Risk models for rebleeding and postoperative mortality in bleeding gastric ulcer.

In order to better define management policies we attempted to construct risk models for rebleeding on initial conservative management and mortality after emergency surgery for failure of medical therapy in 387 patients with bleeding gastric ulcer. Several different models were constructed using logistic regression analysis with validation by the 'leaving-one-out' method. However, despite large patient numbers, modelling in this way is difficult because of inherent wide variation between patients. Suitable models for rebleeding were regarded as rather unsatisfactory, for although overall accuracy was 86%, sensitivity was only 54%. More promising was a model for mortality after emergency surgery which had an accuracy of 93% and a sensitivity of 80%. Such mortality models incorporating age, history of previous malignant disease or dyspepsia, the presence or absence of ascites and total transfusion requirements may well prove to be of value in surgical practice. This paper seeks to examine the process of modelling rebleeding and mortality and of interpreting the models produced.

Aged↗
PubMed1990

Doxorubicin for unresectable hepatocellular carcinoma. A prospective study on the addition of verapamil.

A prospective study was conducted to assess the safety and efficacy of the addition of oral verapamil to intravenous Adriamycin (doxorubicin) for the management of patients with unresectable hepatocellular carcinoma (HCC). All 28 patients studied had histologically verified disease, and cirrhosis was present in 20 of the 21 patients with adequate tissue sampling. The overall median survival was 57 days. Chemotherapy was terminated in seven patients after one course of treatment. Partial response and complete response were noted in four patients (19%) and one patient (4.8%), respectively, among the 21 patients evaluated. Side effects related to the chemotherapy were present in all patients studied. Death from fulminating sepsis occurred in three of the 13 patients with leukopenia. Symptomatic myocardial dysfunction developed in one patient. The addition of verapamil apparently did not potentiate the tumoricidal effect of systemic Adriamycin on HCC but probably did increase its complications.

Carcinoma, Hepatocellular↗