Unusual MR appearance in a branchial cyst.
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Adult↗
Biomedical subjects
O Chan
Publications and source records attributed to O Chan.
Pseudosubluxation of C2 on C3 in polytraumatized children--prevalence and significance.
AIM: Pseudosubluxation of C2 on C3 is a recognized physiological variant in the upper cervical spine radiographs of normal children. The aim of this study was to determine the prevalence of this variant in children admitted with serious polytrauma, and to explore its significance in this setting. PATIENTS AND METHODS: A retrospective review was performed of 138 patients under 16 years of age admitted with polytrauma via The Helicopter Emergency Medical Service. All patients wore hard collars and underwent immediate horizontal beam lateral cervical spine radiography. Normal and C2/C3 pseudosubluxation groups were defined using standard criteria. The two groups were compared in terms of age, presence of an endotracheal tube, injury severity, and outcome. RESULTS: There were 108 (78.3%) children in the normal group and 30 (21.7%) in the C2/C3 pseudosubluxation group. No significant differences in sex ratio, intubation status, injury severity, or outcome were found. Patients in the pseudosubluxation group were significantly younger. CONCLUSION: In paediatric polytrauma it is essential to establish the integrity of the cervical spine promptly as this will deter unnecessary further imaging and investigation. In our study 21.7% of cases had C2/C3 pseudosubluxation on admission radiographs. We have shown that C2/C3 pseudosubluxation has no significant association with intubation status, injury severity, or outcome. We conclude that C2/C3 pseudosubluxation can be considered a benign variant even in the setting of polytrauma.
Adolescent↗
Untreated chronic lymphocytic leukemia concurrent with or followed by acute myelogenous leukemia or myelodysplastic syndrome. A report of five cases and review of the literature.
Although it has been known that patients with chronic lymphocytic leukemia (CLL) have a higher frequency of second malignant neoplasms, the development of acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) in these patients is extremely rare. Most reported cases have been therapy-related. In this article, we report the clinical and immunophenotypic features of 5 cases of untreated CLL concurrent with or followed by the development of AML or MDS. All 5 patients were men, with ages ranging from 57 to 87 years (mean, 73.8 years). Four patients had AML and 1 patient had refractory anemia with ringed sideroblasts. In the 4 cases of AML and CLL, 2 distinct cell populations (i.e., myeloblasts and lymphocytes) were identified morphologically and/or immunophenotypically. Our findings support that this rare concurrence of AML or MDS and untreated CLL may represent 2 separate disease processes.
Aged↗
A new role for B cells in systemic autoimmunity: B cells promote spontaneous T cell activation in MRL-lpr/lpr mice.
A conventional view of the pathogenesis of systemic lupus erythematosus has emerged. The role of B cells is to secrete pathogenic autoantibodies, while the role of T cells is to provide help for autoantibody-producing B cells. A problem with this view is that spontaneous T cell activation as well as T cell infiltration of organs such as kidney and skin are prominent features in systemic lupus erythematosus patients and murine models of lupus. The identification of T cell infiltrates, in particular, suggests that autoantibody-mediated damage may be only part of the story and that T cells could also play a primary role in immune-mediated pathology. To test the role of B cells directly, we previously generated autoimmune-prone MRL-lpr/lpr mice that lack B cells. The complete absence of T cell infiltrates in these mice was surprising, and it prompted us to examine whether a key role of B cells in disease evolution is to prime autoreactive T cells. Here we demonstrate, by comparing B cell-deficient and control mice, that the expansion of activated and memory T cells in the MRL-lpr/lpr mouse is indeed highly dependent on B cells. These results suggest a novel role for B cells in autoimmune disregulation.
Age Factors↗
Tuberculosis of the mandible in a child.
The incidence of notification of tuberculosis is increasing in the developed world. The disease has a variable mode of presentation and therefore diagnosis is not easy. We present an unusual case of tuberculosis involving the ramus of the mandible in a six-year-old boy and outline its management.
Child↗
Potential of limited day 21 post-chemotherapy CT scan in predicting need for post-chemotherapy surgery in nonseminomatous testicular germ cell cancer.
UNLABELLED: Nonseminomatous germ cell cancers (NSGCC) have a varied response to chemotherapy, some melting away with resultant cure, some have tumour stem cell necrosis and residual benign disease whilst others are resistant to treatment. The latter two require surgical excision in order to identify those needing high intensity chemotherapy. OBJECTIVE: The aim of this study was to investigate whether it was possible to give an earlier prediction of need for surgery after chemotherapy on the basis of a limited CT scan performed after the first course. MATERIALS AND METHODS: Twenty-three patients with metastatic NSGCC undergoing induction chemotherapy were studied. The site of the maximum disease was noted before treatment and only this area was rescanned at day 21. The change in disease bulk, measured as maximum transverse diameter (MTD), was compared with appearances on a CT scan immediately after chemotherapy and post-treatment response. RESULTS: Of those patients showing a poor response on the day 21 scan (i.e. no change, or less than 50% reduction in MTD), 70% required early surgical excision of residual disease, while none of the good responders (i.e. greater than 50% reduction in MTD), required immediate surgery (p < 0.001). CONCLUSION: It is concluded that a limited day 21 CT scan may represent an independent predictor of good and poor response to chemotherapy, thus enabling reduction in chemotherapy and its toxicity in good responders and early identification of those who may need surgical excision, thereby permitting easier scheduling of these often difficult surgical procedures.
Adult↗
The roles of B cells in MRL/lpr murine lupus.
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Animals↗
A transforming growth factor beta 1 receptor type II mutation in ulcerative colitis-associated neoplasms.
BACKGROUND & AIMS: Numerous gastrointestinal tumors, notably sporadic and ulcerative colitis (UC)-associated colorectal carcinomas and dysplasias, gastric cancers, and esophageal carcinomas, manifest microsatellite instability. Recently, a transforming growth factor beta 1 type II receptor (TGF-beta 1RII) mutation in a coding microsatellite was described in colorectal carcinomas showing instability. One hundred thirty-eight human neoplasms (61 UC-associated, 35 gastric, 26 esophageal, and 16 sporadic colorectal) were evaluated for this TGF-beta 1RII mutation. METHODS: Whether instability was present at other chromosomal loci in these lesions was determined. In lesions manifesting or lacking instability, the TGF-beta 1RII coding region polydeoxyadenine (poly A) microsatellite tract was polymerase chain reaction amplified with 32P-labeled deoxycytidine triphosphate. Polymerase chain reaction products were electrophoresed on denaturing gels and exposed to radiographic film. RESULTS: Three of 18 UC specimens with instability at other chromosomal loci (17%) showed TGF-beta 1RII poly A tract mutation, including 2 cancers and 1 dysplasia; moreover, 2% of UC specimens without instability (1 of 43) (1 cancer), 81% of unstable sporadic colorectal cancers (13 of 16), and none of the 61 stable or unstable gastric or esophageal cancers contained TGF-beta 1RII mutations. CONCLUSIONS: Mutational inactivation of the poly A microsatellite tract within TGF-beta 1RII occurs early and in a subset of unstable UC neoplasms and commonly in sporadic colorectal cancers but may be rare in unstable gastric and esophageal tumors.
Activin Receptors, Type I↗
Infrequent DPC4 gene mutation in esophageal cancer, gastric cancer and ulcerative colitis-associated neoplasms.
Homozygously Deleted in Pancreatic Cancer 4 (DPC4), a recently identified candidate tumor suppressor gene, was previously shown to be altered in human pancreatic cancers. We examined DPC4 mutation in 30 examples of three other types of gastrointestinal malignancy: 10 esophageal cancers, 10 gastric cancers and 10 colorectal cancers occurring in the preneoplastic condition, ulcerative colitis. The entire coding region of DPC4 (including all 11 exons) was analysed by either direct sequencing of PCR product or the in vitro synthesized protein assay. No coding region mutations of DPC4 were found in any of the samples examined. Our results suggest that inactivation of DPC4 may not be important in the majority of these types of gastrointestinal cancer.
Colitis, Ulcerative↗
Chest trauma.
Trauma is a major cause of morbidity and mortality worldwide. Despite the advent of specialised trauma centres the outcome of patients who sustain major trauma remains disappointing. Plain radiography and more advanced imaging techniques such as ultrasound, computerised tomography (CT) and angiography, have a major role to play in the early decision making and subsequent management of patients who sustain polytrauma. This article discusses the choice of emergency imaging techniques available in chest trauma for clinicians and radiologists; their evaluation and some of the common pitfalls that may lead to errors of interpretation.
Aorta↗
Case report: pulmonary arterial obstruction caused by recurrent tumour treated with endovascular stenting.
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Arterial Occlusive Diseases↗
Alterations of transforming growth factor-beta 1 receptor type II occur in ulcerative colitis-associated carcinomas, sporadic colorectal neoplasms, and esophageal carcinomas, but not in gastric neoplasms.
BACKGROUND & AIMS: Gastric cancers, sporadic colorectal cancers, and ulcerative colitis (UC)-associated colorectal carcinomas and dysplasias manifest microsatellite instability (MI); however, esophageal carcinomas rarely exhibit MI. Recently, a transforming growth factor-beta 1 type II receptor (TGF-beta 1RII) mutation in a coding microsatellite was described in primary colorectal carcinomas demonstrating MI. No previous studies of TGF-beta 1RII have addressed mechanisms of inactivation other than MI in human tumors; furthermore, MI-negative tumors have not been examined for TGF-beta 1RII mutation. We evaluated 138 primary human neoplasms for mutation in the poly-A microsatellite tract of TGF-beta 1RII. Additionally, a group of esophageal tumors was evaluated for the expression of TGF-beta 1RII messenger RNA (mRNA). METHODS: First, we determined whether MI was present at other chromosomal loci in these lesions. The poly-deoxyadenine (poly-A) microsatellite tract within the TGF-beta 1RII coding region was then PCR-amplified. In a group of MI-negative esophageal tumors, RT-PCR was performed to determine the expression of TGF-beta 1RII mRNA. RESULTS: Among 17 MI+ UC specimens, 3 (18%) demonstrated TGF-beta 1RII poly-A tract mutation (2 cancers and 1 dysplasia), while 2 (4%) of 44 MI-negative UC specimens (1 dysplasia and 1 tumor), and 13 (81%) of 16 MI+ sporadic colorectal cancers, contained TGF-beta 1RII poly-A mutation. No gastric or esophageal tumors contained TGF-beta 1RII mutation. Among 21 MI-negative esophageal carcinomas. 6 cases (28.5%) had TGF-beta 1RII transcripts that were low or undetectable by RT-PCR. CONCLUSIONS: Mutation within the poly-A microsatellite tract of TGF-beta 1RII occurs early in a subset of UC-neoplasms and commonly in sporadic colorectal cancers, but may be rare in MI+ gastric tumors. Diminished expression of TGF-beta 1RII mRNA in esophageal tumors suggests that mechanisms of inactivation in this gene other than MI play a role in esophageal carcinogenesis.
Colitis, Ulcerative↗
Adenomatous polyposis coli gene mutations in ulcerative colitis-associated dysplasias and cancers versus sporadic colon neoplasms.
Adenomatous polyposis coli (APC) gene mutations occur in most sporadic colonic adenomas and carcinomas. Precursor lesions of ulcerative colitis (UC)-associated colon carcinomas, although morphologically similar to sporadic adenomas, may be biologically distinct from them and are, in fact, managed differently. Since sporadic adenomas may also occur in UC, a method of discriminating between these forms of neoplasia could have clinical utility. We examined 33 patients with UC-associated dysplasias and cancers and 23 sporadic colon neoplasms in a side-by-side comparison for APC mutations. Codons 686-1693, containing 64% of all reported APC mutations (the mutation cluster region), were screened for truncating mutations using an in vitro synthesized protein assay. Two of thirty-three patients (6%) with UC-associated dysplasias and cancers had a total of three truncating APC mutations, all in frank carcinomas, while 17 of 23 (74%) with sporadic colonic neoplasms had mutations. DNA sequencing confirmed two mutations in codon 1460, replacing arginine with a stop codon, as well as one 2-base pair deletion, resulting in a frameshift and a stop at codon 1477. One specimen contained one each of these APC mutations. This apparent contrast in mutation rates at the mutation cluster region of APC is consistent with other biological characteristics separating sporadic colon neoplasms from UC-associated dysplasias and cancers. These data raise the possibility that nonadenomatous UC dysplasias may arise by a molecular pathway distinct from that prevailing in sporadic colon carcinogenesis, and they suggest a molecular assay to discriminate between sporadic adenomas and dysplasias occurring in UC.
Base Sequence↗
The trauma team concept and its implementation in a district general hospital.
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Emergency Service, Hospital↗
Preliminary observations on the changing roles of malaria vectors in southern Belize.
A survey for larval and adult Anopheles mosquitoes was conducted in Toledo District of southern Belize during August-September 1992. We surveyed for larvae in 145 habitats and conducted paired indoor-outdoor collections of adult mosquitoes landing on humans at 6 houses. In 1940-41, Kumm and Ram reported Anopheles darlingi females to be the most common Anopheles mosquitoes inside houses and reported no specimens of Anopheles vestitipennis in southern Belize. In our 1992 survey we found no An. darlingi mosquitoes either as adults or larvae. More An. vestitipennis females were captured indoors than outdoors, whereas most Anopheles albimanus and Anopheles apicimacula females were captured outdoors. All 3 species were represented occasionally in 145 collections of larvae from diverse habitats. Anopheles vestitipennis now appears to be a potentially important vector of malaria during the wet season in Toledo District.
Animals↗
Case report: widespread tuberculosis in sickle cell disease.
We report a case of a patient with sickle cell disease who presented with mesenteric nodes and pulmonary TB and who subsequently relapsed on triple therapy and presented with disseminated tuberculous osteomyelitis and cervical lymphadenopathy. We emphasize the difficulty of establishing the diagnosis at all stages of presentation.
Adolescent↗
Case report: misdiagnosis of an atypical pericardial cyst presenting in a patient with chest trauma.
We report a patient who presented following major trauma to the chest who had a pericardial cyst in the anterior aspect of the upper mediastinum, the high CT number of which led to a misdiagnosis. The patient underwent surgery when the pericardial cyst was excised.
Adolescent↗
Misinterpretation of the upper parathyroid adenoma on thallium-201/technetium-99m subtraction scintigraphy.
Pre-operative thallium-technetium subtraction scintigraphy of 50 patients with primary hyperparathyroidism, which was subsequently proven on histology to be due to an adenoma, was compared with operative findings. Six scans were negative and seven uninterpretable. Of the remaining 37 patients, 34 had correct scan prediction of the anatomical locations of the adenomas. On examination of the origins of the adenomas, all six scintigraphic predictions of upper adenomas corresponded to tumours arising from the upper gland found at operation. Of the 25 lower predictions, there was one false positive and 16 were correct, i.e. of lower gland origin, but eight were found to originate from the upper gland. This misinterpretation is though to be due to the prolapse of an adenoma arising from the upper gland towards the lower pole of the thyroid, thereby mimicking a lower lesion on the scan.
Adenoma↗