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Biomedical subjects

C S Ng

Publications and source records attributed to C S Ng.

At least 55 records · Page 3Linked to original sources
PubMed1999

Retroperitoneoscopic surgery is not associated with increased carbon dioxide absorption.

PURPOSE: Previous studies have suggested that retroperitoneal laparoscopy is associated with greater carbon dioxide absorption and related postoperative morbidity, such as subcutaneous emphysema and pneumothorax. We prospectively compared the effects of carbon dioxide absorption during transperitoneal and retroperitoneal laparoscopic renal and adrenal surgery at our institution. MATERIALS AND METHODS: Data were collected prospectively on 51 patients who underwent laparoscopic renal (26) or adrenal (25) surgery via the transperitoneal (18) or retroperitoneal (33) approach from September 1997 to February 1998. RESULTS: There was no significant difference in carbon dioxide elimination in patients who underwent transperitoneal laparoscopy compared to retroperitoneoscopy at any interval. Subcutaneous emphysema occurred in 12.5% of the transperitoneal and 45% of the retroperitoneal group (p = 0.09). Patients with subcutaneous emphysema had greater carbon dioxide elimination during the first 2.5 hours of insufflation compared to those without subcutaneous emphysema and, thereafter, carbon dioxide elimination decreased to baseline. CONCLUSIONS: In contrast to previous reports our prospective nonrandomized study suggests that retroperitoneoscopy is not associated with greater carbon dioxide absorption compared to transperitoneal laparoscopy. Patients with subcutaneous emphysema exhibited only transient increases in carbon dioxide absorption above control levels.

Absorption↗
PubMed1998

Costochondral junction fractures and intra-abdominal trauma in non-accidental injury (child abuse).

Rib fractures are a common skeletal manifestation of non-accidental injury (NAI) in infants and young children and are generally considered to be highly specific for abuse. There are, however, relatively few descriptions of fractures involving the costochondral junctions in NAI. We present three children (two boys, one girl; 7, 18, and 36 months of age) with anterior rib fractures which involved the sixth to ninth costochondral junctions. The fractures were bilateral in two children and symmetrical in one. They had appearances analogous to 'bucket handle' metaphyseal fractures of long bones. They were difficult to visualise and healed with minimal callus formation. These fractures were associated with major abdominal visceral injuries, which in themselves carry a significant morbidity and mortality. The importance of recognising such fractures is highlighted.

Abdominal Injuries↗
PubMed1998

Correlation of CT with histopathological findings in patients with gastric and gastro-oesophageal carcinomas following neoadjuvant chemotherapy.

UNLABELLED: Gastric carcinoma is the fourth commonest cause of death from malignant disease in United Kingdom. In the Western hemisphere, it usually presents with advanced disease, which contributes to its very poor prognosis. Pre-operative (neoadjuvant) chemotherapy offers the possibility of down-staging such tumours and the potential to render tumours operable. Computed tomography (CT) plays a central role in the assessment of patients presenting with the disease, and in those who undergo chemotherapy, in evaluating their response. OBJECTIVE: This study was undertaken to evaluate the role of CT in predicting loco-regional spread of tumour following neoadjuvant chemotherapy in non-metastatic gastric and gastro-oesophageal cancers. METHODS AND MATERIALS: We correlated CT evidence of loco-regional spread with pathological findings following surgery in 21 patients who received pre-operative chemotherapy. RESULTS: Residual masses were seen on CT in 19 patients, and 15 contained active tumour, although in four patients no viable tumour was demonstrated at histopathology. The overall accuracy of CT in assessing loco-regional disease was disappointing with sensitivities, specificities, positive and negative predictive values of 57%, 43%, 75% and 33%, respectively. CONCLUSIONS: We conclude that CT is not accurate in identifying residual loco-regional spread and therefore should not preclude surgery in those patients who have received neoadjuvant chemotherapy.

Adult↗
PubMed1998

Primary non-Hodgkin's lymphoma of the nose and nasopharynx: clinical features, tumor immunophenotype, and treatment outcome in 113 patients.

PURPOSE: To study the clinical features and outcome for primary non-Hodgkin's lymphomas of the nose/nasopharynx (NNP-NHLs) according to immunophenotype. PATIENTS AND METHODS: One hundred thirteen Chinese patients with primary NNP-NHLs that belonged to the categories E, F, G, or H according to the Working Formulation (WF), with full immunophenotypic data and complete clinical follow-up data, were analyzed in this retrospective study. RESULTS: Ninety (79.6%) patients had localized (stage I or II) disease, while 23 (20.4%) had stage III or IV disease. The lymphomas in 51 (45.1%), 24 (21.3%), and 38 (33.6%) patients showed natural killer (NK)/T- (CD56-positive), T-cell, and B-cell immunophenotype, respectively. Seventy-three patients (65.8%) achieved a complete remission, of whom 34 (46.6%) subsequently relapsed. The median follow-up time for those alive was 88 months. The 5-year actuarial disease-free and overall survival rates were 34.4% and 37.9%, respectively. Multivariate analysis showed that only stage and immunophenotype were significant for survival. NK/T lymphomas were distinctive among the three immunophenotypes in the following aspects: the highest male-to-female ratio, more frequent involvement of the nasal cavity alone, higher risk of dissemination to the skin, more frequent development of hemophagocytic syndrome, and the worst prognosis (overall median survival, 12.5 months). CONCLUSION: The three immunophenotypes studied are shown to exhibit different clinical patterns. Since the NK/T phenotype carries the worst prognosis, patients who present with NNP-NHL should have their tumors analyzed for CD56 expression.

Adolescent↗
PubMed1998

Medium-term results of percutaneous, arthroscopically-assisted osteosynthesis of fractures of the tibial plateau.

We carried out percutaneous, arthroscopically- and fluoroscopically-assisted osteosynthesis of fractures of the tibial plateau in 52 patients, of whom 38 were assessed using the HSS knee score and standing radiographs. We reviewed 31 AO type-B fractures and seven type-C fractures after a mean follow-up of five years (1 to 14). Fixation was achieved using percutaneous screws and/or an external frame; 33 associated intra-articular injuries, diagnosed in 21 out of the 38 patients, were treated arthroscopically. Subjectively, 94.7% of the patients reviewed were satisfied. According to the HSS knee score 78.9% of the results were excellent, 13.2% good, 7.9% fair and none was poor. Narrowing of the joint space was found in 28.9% of the injured and 5.3% of the unaffected knees and axial deviation of 5 degrees to 10 degrees in 15.8% of the injured and 10.5% of the unaffected knees. Of the 52 fractures, reduction was incomplete in one, and in two secondary displacement occurred, of which one required corrective osteotomy. Deep-venous thrombosis occurred in four cases. The technique has proved to be safe but demanding. It facilitates diagnosis and appropriate treatment of associated intra-articular lesions.

Adolescent↗
PubMed1998

Acute Wernicke's encephalopathy complicating chronic gallstone ileus.

An autopsy performed on a 53-year-old man who had unrelieved obstruction of the small bowel due to gallstone ileus revealed morphological features that were typical of acute Wernicke's encephalopathy. The likely sequence of disease in this patient was the development of thiamine deficiency owing to the unrelieved intestinal obstruction, which resulted in the development of acute Wernicke's encephalopathy. A high clinical awareness is required for the diagnosis of acute Wernicke's encephalopathy in patients with malnutrition from any cause.

Journal Article↗
PubMed1997

Nonnasal lymphoma expressing the natural killer cell marker CD56: a clinicopathologic study of 49 cases of an uncommon aggressive neoplasm.

Expression of the natural killer (NK) cell antigen CD56 is uncommon among lymphomas, and those that do are almost exclusively of non-B-cell lineage and show a predilection for the nasal and nasopharyngeal region. This study analyzes 49 cases of nonnasal CD56+ lymphomas, the largest series to date, to characterize the clinicopathologic spectrum of these rare neoplasms. All patients were Chinese. Four categories could be delineated. (1) Nasal-type NK/T cell lymphoma (n = 34) patients were adults 21 to 76 years of age (median, 50 years), including 25 men and 9 women. They presented with extranodal disease, usually in multiple sites. The commonest sites of involvement were skin, upper aerodigestive tract, testis, soft tissue, gastrointestinal tract, and spleen. Only 7 cases (21%) apparently had stage I disease. The neoplastic cells were often pleomorphic, with irregular nuclei and granular chromatin, and angiocentric growth was common. The characteristic immunophenotype was CD2+ CD3/Leu4- CD3epsilon+ CD56+, and 32 cases (94%) harbored Epstein-Barr virus (EBV). Follow-up information was available in 29 cases: 24 died at a median of 3.5 months; 3 were alive with relapse at 5 months to 2.5 years; and 2 were alive and well at 3 and 5 years, respectively. (2) Aggressive NK cell leukemia/lymphoma (n = 5) patients presented with hepatomegaly and blood/marrow involvement, sometimes accompanied by splenomegaly or lymphadenopathy. The neoplastic cells often had round nuclei and azurophilic granules in the pale cytoplasm. All cases exhibited an immunophenotype of CD2+ CD3/Leu4- CD56+ CD16- CD57- and all were EBV+. All of these patients died within 6 weeks. (3) In blastoid NK cell lymphoma (n = 2), the lymphoma cells resembled those of lymphoblastic or myeloid leukemia. One case studied for CD2 was negative and both cases were EBV-. One patient was alive with disease at 10 months and one was a recent case. (4) Other specific lymphoma types with CD56 expression (n = 8) included one case each of hepatosplenic gammadelta T-cell lymphoma and S100 protein+ T-cell lymphoproliferative disease and two cases each of T-chronic lymphocytic/prolymphocytic leukemia, lymphoblastic lymphoma, and true histiocytic lymphoma. All of these cases were EBV-. Six patients died at a median of 6.5 months. Nonnasal CD56+ lymphomas are heterogeneous, but all pursue a highly aggressive clinical course. The nasal-type NK/T-cell lymphoma and aggressive NK cell leukemia/lymphoma show distinctive clinicopathologic features and a very strong association with EBV. Blastoid NK cell lymphoma appears to be a different entity and shows no association with EBV.

Adolescent↗
PubMed1997

Validation of a high-performance liquid chromatographic assay method for pharmacokinetic evaluation of busulfan.

The development and validation of a high-performance liquid chromatographic (HPLC) assay for determination of busulfan concentrations in human plasma for pharmacokinetic studies is described. Plasma samples containing busulfan and 1,6-bis(methanesulfonyloxy)hexane, and internal standard, were prepared by derivatization with sodium diethyldithiocarbamate (DDTC) followed by addition of methanol and extraction with ethyl acetate. The extract was dried under nitrogen and the samples reconstituted with 100 microl of methanol prior to HPLC determination. Chromatography was accomplished using a Waters NovaPak octadecylsilyl (ODS) (150 x 3.9 mm I.D.) analytical column, NovaPak ODS guard column, and mobile phase of methanol-water (80:20, v/v) at a flow-rate of 0.8 ml/min with UV detection at 251 nm. The limit of detection was 0.0200 microg/ml (signal-to-noise ratio of 6) with a limit of quantitation (LOQ) of 0.0600 microg/ml for busulfan in plasma. Calibration curves were linear from 0.0600 to 3.00 microg/ml in plasma (500 microl) using a 1/y weighting scheme. Precision of the assay, as represented by C.V. of the observed peak area ratio values, ranged from 4.41 to 13.5% (13.5% at LOQ). No day-to-day variability was observed in predicted concentration values and the bias was low for all concentrations evaluated (bias: 0 to 4.76%; LOQ: 2.91%). The mean derivatization and extraction yield observed for busulfan in plasma at 0.200, 1.20 and 2.00 microg/ml was 98.5% (range 93.4 to 107%). Plasma samples containing potential busulfan metabolites and co-administered drugs, which may be present in clinical samples, provided no response indicating this assay procedure is selective for busulfan. This method was used to analyze plasma concentrations following administration of a 1 mg/kg oral busulfan dose.

Busulfan↗
PubMed1997

T- and T/natural killer-cell lymphomas of the salivary gland: a clinicopathologic, immunohistochemical and molecular study of six cases.

Primary salivary gland lymphomas are almost always of B lineage, with most being represented by low grade B-cell lymphoma of mucosa-associated lymphoid tissue. This study characterizes the rare non-B-cell lymphomas of the salivary gland based on an analysis of six cases. All patients were men, with a mean age of 53.5 years. They presented with submandibular or parotid mass, which on histological examination showed extensive interstitial infiltration by small, medium-sized, or large lymphoid cells. There was prominent invasion and expansion of the ducts and acini in five cases. Angioinvasion was evident in two cases. Three cases were of T lineage and were CD56 negative; one of these cases expressed CD30. Three cases showed an immunophenotype of CD2+ CD3(f)- CD3(p)+ CD56+, consistent with T/natural killer (NK) cell lymphoma. In situ hybridization for Epstein-Barr virus (EBV)-encoded early nuclear RNA (EBER) showed positive reaction exclusively in the three CD56+ cases. Clonal T-cell populations were shown in two CD56-negative cases by polymerase chain reaction on paraffin sections using primers for the T-cell-receptor (TCR) gamma-chain gene, but not in the other four cases (the three CD56+ cases and one CD56- case). Four patients (two CD56+ and two CD56-) died within 3 years, and two were disease free at 4 and 1.5 years, respectively. This study shows that salivary gland T- or T/NK-cell lymphomas cannot be reliably distinguished from B-cell lymphomas on morphological grounds alone, because both can show prominent lymphoepithelial lesions. It appears that T/NK-cell lymphomas, which are often extranodal in localization and strongly associated with Epstein-Barr virus (EBV), show a predilection to involve the salivary glands as well.

Aged↗
PubMed1997

CD56+ putative natural killer cell lymphomas: production of cytolytic effectors and related proteins mediating tumor cell apoptosis?

Apoptosis is a regulated form of cell death that may be triggered by natural killer (NK) or cytotoxic T cells, which effect target cell lysis by cytolytic effector and related proteins through complex intracellular signals. This study was aimed to investigate whether there is selective expression of these cytolytic markers in the putative NK-cell lymphomas and whether there is correlation with zonal tumor cell death in these tumors. Expression of the cytolytic effectors perforin, granzyme B9, and the granule membrane protein TIA1 were examined in 24 putative NK-cell lymphomas, 18 postthymic T-cell lymphomas (one case CD8+ CD56+ and three anaplastic large cell lymphomas (ALCL), three T-lymphoblastic lymphomas, and 20 B-cell lymphomas. Nineteen (79%) putative NK-cell lymphomas expressed perforin, and all 24 cases expressed granzyme B9 and TIA1. The only CD8+ CD56+ postthymic T-cell lymphoma also expressed all three cytolytic markers, two CD8- ALCL expressed TIA1; other postthymic T-cell, T-lymphoblastic, and B-cell lymphomas were consistently negative. There was strong correlation between percentage perforin-positive cells and zonal tumor cell death. Angioinvasion, in contrast, was present only in a proportion (37%) of these lymphomas despite the frequent presence of zonal tumor cell death (71%). We propose that cytolytic effector and related proteins produced by putative NK and some CD8+ CD56+ postthymic T-cell lymphomas, probably in conjunction with other mechanisms, may effect massive tumor cell apoptosis. The frequent expression of cytolytic effector markers in the CD2+ surface CD3- CD56+ putative NK-cell lymphomas lends further support to their probable NK cell origin.

Apoptosis↗
PubMed1997

Intravascular lymphomatosis: a case presenting with encephalomyelitis and reactive haemophagocytic syndrome diagnosed by renal biopsy.

AIMS: To report an unusual instance of intravascular lymphomatosis presented with encephalomyelitis and reactive haemophagocytic syndrome. There was no skin involvement. The diagnosis was made on a renal biopsy. METHODS AND RESULTS: The marrow smear was air dried and stained with Diff-Quik. The tissue sections were stained with haematoxylin and eosin. Masson trichrome, periodic acid-Schiff's reagent, Elastic van Gieson's stain, modified hexamine-silver technique and Martius scarlet blue. Immunohistochemistry for CD45, CD20, CD45RO, Factor VIII related antigen, CD31 and CD34 was performed on paraffin-processed tissue. The marrow smear showed active haemophagocytosis in the histiocytes. The renal biopsy showed intravascular lymphomatosis with tumour cells positive for CD45 and CD20. CONCLUSION: The possibility of intravascular lymphomatosis should be considered in patients with reactive haemophagocytic syndrome where the underlying cause cannot be found after thorough investigation.

Adult↗
PubMed1997

Evaluation by magnetic resonance imaging of the inferior vena cava in patients with non-seminomatous germ cell tumours of the testis metastatic to the retroperitoneum.

OBJECTIVE: To assess the role of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in evaluating suspected occlusion of the inferior vena cava (i.v.c.) in patients with abdominal nodal metastases from non-seminomatous germ cell tumours, thus giving information that may be helpful in planning surgery and for determining the need for anticoagulant therapy. PATIENTS AND METHODS: Five patients with abdominal nodal metastases in whom occlusion of the i.v.c. was suspected on computed tomography (CT) were imaged using a 1.5 T MRI scanner. The MRI findings were compared with those from CT. RESULTS: The MR images successfully and clearly detected partial and total occlusions of the i.v.c. by both intraluminal thrombus and extrinsic compression. The technique also clearly detected extensive collateral venous circulation in several cases and in one a cavernous transformation of the i.v.c. In all patients, the MRI studies provided better information than that from CT. CONCLUSION: MRI, and particularly MRA, is a comparatively new technique that is non-invasive and offers the potential of evaluating vascular structures with no need for ionizing radiation or contrast media. This technique, if available, should be chosen for imaging the i.v.c. in patients suspected of having compression or occlusion of the i.v.c.

Adolescent↗
PubMed1997

The investigation of renovascular hypertension in children: the accuracy of radio-isotopes in detecting renovascular disease.

Renovascular disease is an important cause of hypertension in children because it is potentially treatable by surgical or angioplasty techniques. The aim of this study was to assess the accuracy of radio-isotopes (DMSA, DTPA and MAG3) combined with the angiotensin converting enzyme inhibitor, captopril, in detecting children with renovascular hypertension. We retrospectively reviewed the ultrasound and pre- and post-captopril radionuclide studies (either DMSA and/or DPTA and/or MAG3) of children with sustained hypertension investigated at our institution. Renal angiography was used as the 'reference technique'. Thirty-nine children, over a period of 10 years, were evaluated: 17 (44%) children had renovascular disease that involved the proximal three divisions of the renal arteries, some of which were amenable to treatment. The overall sensitivity, specificity, positive predictive value and negative predictive value for detecting such renovascular disease, as assessed by changes between pre- and post-captopril radio-isotope studies, were disappointing at 59%, 68%, 59% and 68%, respectively. When considering only abnormalities in post-captopril studies, these indices were 82%, 41%, 52% and 75%, respectively. Three children with potentially treatable renovascular disease were not identified on the captopril studies. We conclude that renal angiography should remain the 'reference technique' in identifying children suspected of renovascular hypertension.

Adolescent↗
PubMed1997

Gastric malignant schwannoma in a child.

Malignant schwannoma (malignant peripheral nerve sheath tumour, MPNST) is a high grade sarcoma with a potential for local recurrence and distant metastasis that may occur at any site in the body where there is neural tissue. MPNST is rare in children and is unreported in the stomach in the paediatric age group. MPNST presents either as an expanding mass, with or without pain, or in the gastrointestinal tract with haemorrhage or obstruction. Many cases occur without evidence of neurofibromatosis but thers is a reported association between MPNST and neurofibromatosis of up to 50%. MPNST has a higher incidence at sites of previous irradiation. Treatment is by complete surgical excision. Radiology is of value in initial diagnosis and staging prior to surgery. The definitive diagnosis is made on the histopathological appearance and immunohistochemical profile. The findings on barium meal, abdominal ultrasound and CT are presented.

Barium↗
PubMed1997

Redefining the genital abnormality in the Robinow syndrome. -004.

PURPOSE: We defined the anatomical structure of the male genital abnormality in the Robinow syndrome. Features of this syndrome include mesomelic brachymelia of the arms, bifid terminal phalanges of the hands and feet, characteristic facies, skeletal anomalies and hypoplastic external genitalia. MATERIALS AND METHODS: Penile anatomy of 3 patients with the Robinow syndrome was assessed using computerized tomography and magnetic resonance imaging. Results were compared to those of 4 controls who underwent imaging for pelvic malignancies. RESULTS: Cross-sectional imaging showed that normal penile crura were inserted onto the anteromedial aspect of the pubic bone. In contrast, in the Robinow syndrome they were inserted inferiorly and posteriorly onto the medial aspect of the ischial tuberosity. In addition, the crura in the Robinow syndrome extended posterior to a line intersecting both femoral shafts. Compared to controls, there was a significant gap between the symphysis pubis and dorsal aspect of the penis. CONCLUSIONS: The penile anomaly in the Robinow syndrome is due to abnormal insertion of the penile crura, resulting in a penis that appears shorter and more inferiorly placed between the legs.

Abnormalities, Multiple↗
PubMed1997

Combination of "patch, drain, and wait" and home total parenteral nutrition for midgut volvulus with massive ischemia/necrosis.

The successful use of a combination of "patch, drain, and wait" (PDW) and home total parenteral nutrition (TPN) in the management of a case of acute, catastrophic midgut volvulus in a 2-year-11-month-old boy with near-total ischemia/necrosis of his small intestine is reported. The PDW approach to the highly effective management of acute midgut ischemia/necrosis in infancy and childhood (necrotizing enterocolitis and midgut volvulus) involves maximum gut salvage by avoidance of resection, stoma formation, or both through the use of extensive peritoneal cavity drainage by Penrose drains, TPN, and broad-spectrum antibiotics. The extensive peritoneal drainage fosters capture of enteric fistulas with the formation of enterostomies at drain exit sites, while adhesions and ischemia/inflammation-induced hypervascular obliteration of the peritoneal cavity diminish the potential for peritonitis (no peritoneal cavity, no peritonitis) and facilitate impressive salvage of seemingly hopelessly lost ischemic/necrotic gut (a simulation of the in utero ischemic gut process leading to atresias and some varying, but generally mild, gut loss) while simultaneously contributing to the resorption of absolutely non-salvageable gut and the creation of a remarkably clean and adhesion-free peritoneal cavity resembling that of a newborn infant with midgut intestinal atresia.

Abdomen, Acute↗