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Biomedical subjects

R Kay

Publications and source records attributed to R Kay.

At least 19 recordsLinked to original sources
PubMed2004

Clinical and electrophysiological features in Chinese patients with Kennedy's disease.

Kennedy's disease is a X-linked neuromuscular disorder caused by an expanded trinucleotide repeat in the androgen receptor gene. To ascertain the clinical diagnosis of Kennedy's disease in a Chinese population, we used a rapid, accurate PCR-based sizing method for the CAG repeat allelotype. The clinical and electrophysiological features of affected patients are described. The CAG repeats ranged from 43 to 53 and were inversely correlated with the age of onset (r = -0.63; P < 0.005).

Action Potentials↗
PubMed2003

Role of magnetic resonance imaging for preoperative evaluation of patients with refractory epilepsy.

OBJECTIVE: To investigate the magnetic resonance imaging characteristics of patients with refractory epilepsy and the relationship to progression to surgery. DESIGN: Prospective observational study. SETTING: University teaching hospital, Hong Kong. PATIENTS: Patients undergoing preoperative evaluation for epilepsy surgery. MAIN OUTCOME MEASURE: Cranial magnetic resonance imaging findings, correlation with electroencephalographic results, and percentage of patients who were considered suitable candidates for surgery. RESULTS: Structural abnormalities associated with refractory epilepsy in 100 consecutive patients were mesial temporal sclerosis (30%), neocortical sclerosis (23%), vascular malformation (7%), neuronal migration disorders (7%), and tumours (5%). Normal brain scans were found for 28% of patients. Fourteen of 30 (46%) patients with medial temporal lobe lesions at magnetic resonance imaging were suitable candidates for surgery compared with 8/42 (19%) patients with extrahippocampal lesions (odds ratio=3.7; 95% confidence interval, 1.3-10.6; P<0.012). CONCLUSION: Mesial temporal sclerosis was the most common pathology in patients with refractory epilepsy. At the Prince of Wales Hospital, for patients who have undergone a basic magnetic resonance imaging protocol and surface electroencephalography, the result of cranial magnetic resonance imaging is an important determinant for whether patients will undergo surgery.

Adolescent↗
PubMed2002

Lack of association between CYP1A1 polymorphism and Parkinson's disease in a Chinese population.

Apart from very few families who have a direct cause from genetic mutation, causes of most Parkinson's disease (PD) remain unclear. Many allelic association studies on polymorphism of different candidate genes have been studied. Although these association studies do not imply a causal relationship, it does warrant further studies to elucidate the pathophysiologic significance. CYP1A1 polymorphisms have been reported to be associated with PD in a Japanese population sample. Since CYP1A1 transforms aromatic hydrocarbons into products that may be neurotoxic and perhaps lead to PD, we therefore undertook a study to look at the possible association of CYP1A1 polymorphism and PD in a Chinese population. Contrary to the Japanese result, we did not find any statistically significant difference between the PD group and the control group in our study with a bigger sample size.

Aged↗
PubMed2002

Lack of clinical utility of the Siriraj Stroke Score.

BACKGROUND: The ability to distinguish between infarct and haemorrhage is essential to the management of acute cerebrovascular disease. In hospitals where emergency neuroimaging is not available, the use of stroke scores has been proposed to distinguish ischaemic from haemorrhagic stroke. AIMS: To determine the accuracy of the Siriraj Stroke Score in distinguishing ischaemic from haemorrhagic stroke in a cohort of Chinese patients. METHODS: We prospectively assessed and calculated the Siriraj Stroke Score from 253 patients with acute stroke. The sensitivity, specificity, positive and negative predictive values of this score were determined. RESULTS: For cerebral haemorrhage, the sensitivity and specificity were both 90% or above, but the positive predictive value was not greater than 70%. For cerebral infarct, the sensitivity and specificity were around 80%, while the positive predictive value exceeded 90%. Analysis by plotting receiver operating characteristic curves failed to find other cut-off points that would improve the performance of the Siriraj Stroke Score. CONCLUSIONS: Considering the inconsistent results from this study and previous studies of the Siriraj Stroke Score, we suggest that scoring systems that only require a small number of variables are unlikely to achieve the level of accuracy needed for clinical decision-making.

Acute Disease↗
PubMed2002

Effects of the ultrasound contrast-enhancing agent Levovist on the detection of intracranial arteries and stenoses in chinese by transcranial Doppler ultrasound.

Proper assessment of intracranial arteries by transcranial Doppler sonography (TCD) in patients with intracranial stenoses is occasionally made difficult by an insufficient temporal bone window, an unfavourable insonation angle, or low flow velocity or volume. This condition is frequently found in Chinese. In these cases, echocontrast could be helpful. We investigated 48 temporal windows of 24 acute Chinese stroke patients with insufficient native transtemporal insonation conditions before and after the application of the echo enhancer Levovist (galactose/palmitic acid) by an injection pump. We classified the signal quality from four segments of the main intracranial arteries: anterior cerebral artery (A1), main stem of the middle cerebral artery (MCA, M1), intracranial segment of the carotid artery (C1), and posterior cerebral artery (P1). The signal quality was classified as follows: 0 = no signal, 1 = poor, envelope curve does not follow spectrum, 2 = adequate, envelope curve follows spectrum. As compared to the pre-contrast scans, echocontrast allowed for more segments to be evaluated by pulsed Doppler sonography. Before Levovist, only 12% of the segments could be detected, after Levovist 63%. For all arteries, signal quality was better after Levovist, p between 0.0180 and 0.0003. In 3 patients, MCA stenoses with peak systolic Doppler flow velocities above 160 cm/s were found only after Levovist. In patients with poor pre-contrast detection, echocontrast-enhanced TCD allows for more arterial segments to be insonated and for the detection of stenoses unnoted during the non-enhanced investigation.

Aged↗
PubMed2001

The chimeric protein tyrosine kinase ETV6-NTRK3 requires both Ras-Erk1/2 and PI3-kinase-Akt signaling for fibroblast transformation.

There is increasing interest in the potential role of the NTRK family of neurotrophin receptors in human neoplasia. These receptor protein tyrosine kinases (PTKs) are well-known mediators of neuronal cell survival and differentiation, but altered NTRK signaling has also been implicated in mesenchymal, hematopoietic, and epithelial malignancies. We recently identified a novel gene fusion involving one of the neurotrophin receptor genes, NTRK3, in the pediatric solid tumor, congenital fibrosarcoma. In these tumors (and subsequently demonstrated in several other human malignancies), a t(12;15)(p13;q25) rearrangement fuses the 3' portion of the ETV6 gene with exons encoding the PTK domain of NTRK3. The resulting ETV6-NTRK3 fusion protein functions as a chimeric PTK with potent transforming activity. However, previous studies failed to detect interactions between ETV6-NTRK3 and molecules known to link wild-type NTRK3 to its two major effector pathways, namely the Ras-Raf1-Mek1-Erk1/2 mitogenic pathway or the phosphatidylinositol 3'-kinase pathway leading to activation of the AKT survival factor. Therefore, it remains unknown whether ETV6-NTRK3 transformation involves altered NTRK3 signaling. We now report that ETV6-NTRK3 expression in NIH3T3 cells leads to constitutive activation of Mek1 and Akt, as well as to constitutively high expression of cyclin D1. ETV6-NTRK3-induced soft agar colony formation was almost completely abolished by inhibition of either the Ras-Raf1-Mek1-Erk1/2 or the phosphatidylinositol 3'-kinase-Akt pathway. Moreover, this inhibition dramatically reduced expression of cyclin D1. Our results indicate that ETV6-NTRK3 transformation involves a link between known NTRK3 signaling pathways and aberrant cell cycle progression and that Mek1 and Akt activation act synergistically to mediate these effects.

3T3 Cells↗
PubMed2001

Local vs systemic corticosteroids in the treatment of carpal tunnel syndrome.

The authors compared the effectiveness of low-dose, short-term oral prednisolone vs local methylprednisolone injection in a prospective, double-blinded, parallel treatment study of carpal tunnel syndrome (CTS). A single injection of 15 mg methylprednisolone resulted in significant improvement in global symptom scores over a 12-week period. This study demonstrated the superiority of local steroid injection to oral steroid in the treatment of CTS.

Administration, Oral↗
PubMed2001

Stromal testis tumors in children: a report from the prepubertal testis tumor registry.

PURPOSE: Stromal testis tumors are rare and generally exhibit a benign behavior in prepubertal patients. We reviewed the Prepubertal Testis Tumor Registry to elucidate further the behavior of these tumors. MATERIALS AND METHODS: Epidemiological and clinical information on stromal testis tumors was compiled and reviewed from the Prepubertal Testis Tumor Registry. In addition, original pathology reports were requested for all patients registered as having undifferentiated stromal tumors. RESULTS: There were 43 patients registered with stromal tumors. Of the 21 patients with unspecified stromal tumors pathology reports were obtained on 11. Eight patients had truly mixed or undifferentiated stromal tumors. Mean patient age at presentation was 38 months (Leydig cell 70, Sertoli cell 52.5, juvenile granulosa cell 1.5 and mixed/undifferentiated 41.2). No patient with a Leydig cell, Sertoli cell or juvenile granulosa cell tumor had metastases at presentation or metastatic disease during an average 24.6 months of followup. One undifferentiated tumor demonstrated malignant behavior by presenting with metastatic disease. Pathological examination revealed a poorly differentiated tumor with extension into the adjacent tunica and frequent mitotic figures. While other stromal tumors displayed mitotic figures, none showed local invasion. CONCLUSIONS: Stromal testis tumors are rare. Data from the Prepubertal Testis Tumor Registry confirms the benign behavior of most of these tumors. However, undifferentiated stromal tumors may exhibit metastatic behavior. A high index of suspicion is appropriate when there are a large number of mitotic figures, the tumor is poorly differentiated or when local invasion is present in the primary tumor. Metastatic evaluation and close followup are warranted for this select group of patients.

Adolescent↗
PubMed2001

Recurrence after a first untreated seizure in the Hong Kong Chinese population.

PURPOSE: There is wide variation in the reported prognosis after a first unprovoked generalized tonic-clonic convulsion and in the risk factors that are associated with recurrence. Estimates for the risk of recurrence range from 26 to 71%. We investigated the likelihood of a second attack in Hong Kong Chinese patients. METHODS: One hundred thirty-two patients with a first convulsion that was unexplained by acute neurological or medical causes were retrospectively ascertained. Patients' demographic details, potential risk factors for recurrence, and current seizure status were recorded. Survival analysis was performed using the Kaplan-Meier procedure. RESULTS: The cumulative probability of a second attack at 1, 2, 3, and 4 years was 30, 37, 42, and 47%, respectively. Seizures in patients with abnormal computer tomography scans of the brain were associated with an increased risk of recurrence on multivariate analysis. CONCLUSIONS: Thirty percent of the sample population experienced a second seizure after 1 year. An additional 17% continue to be at risk of a second convulsion during the next 3 years.

Adolescent↗
PubMed2001

Renal neoplasms in adult survivors of childhood Wilms tumor.

PURPOSE: Survivors of childhood Wilms tumor have been followed by large collaborative studies for approximately 31 years. In this time a number of second malignant neoplasms have been documented in these Wilms tumor survivors and they are at higher risk for such development compared with the general population. To our knowledge no renal neoplasms have been previously reported in patients successfully treated for Wilms tumor in childhood. MATERIALS AND METHODS: We reviewed the cases of 4 adults in whom Wilms tumor was treated in childhood by radical nephrectomy and adjuvant therapy and who presented to our institution with complex cystic or solid renal masses in the contralateral kidney. Parameters, including patient age at Wilms tumor diagnosis, Wilms tumor treatment modalities, age at second malignant neoplasm presentation and resected renal lesion pathology were outlined. A thorough literature review was performed to identify the development of renal malignancies as second malignant neoplasms in survivors of Wilms tumor in childhood. RESULTS: The International Society of Pediatric Oncology and National Wilms Tumor Study have followed patients treated for Wilms tumor for no greater than 31 years. Renal neoplasms, including 2 renal cell carcinomas, 1 oncocytoma and 1 atypical cyst, in the solitary remaining kidney of relatively young adults 34 to 50 years old who were treated for Wilms tumor greater than 31 years ago were successfully treated with partial nephrectomy at our institution. Neither the International Society of Pediatric Oncology nor National Wilms Tumor Study has identified renal cell carcinoma as a second malignant neoplasm in patients successfully treated for Wilms tumor. CONCLUSIONS: Our experience suggests that relatively young adults with a history of childhood treatment for Wilms tumor may be at increased risk for renal neoplasms at ages not yet achieved by those enrolled in large multicenter trials. This possibility should be considered when planning the long-term followup of these patients. The potential to develop this type of second malignant neoplasm again raises the clinical issue of performing a primary nephron sparing procedure in children presenting with Wilms tumor.

Adenoma, Oxyphilic↗
PubMed2001

A pilot study of microembolic signals in patients with middle cerebral artery stenosis.

OBJECTIVE: There has been limited data on the frequency of microembolic signals in patients with middle cerebral artery (MCA) stenosis, especially during the acute phase of stroke. Using transcranial Doppler, the authors prospectively monitored the MCA segments distal to stenosis in 4 groups of patients for 30 minutes: (1) symptomatic patients with acute ischemic stroke and MCA stenosis, (2) asymptomatic group patients with asymptomatic MCA stenosis, (3) control patients with acute ischemic stroke of undetermined etiology, and (4) normal people. A total of 60 patients completed the study. There were no microembolic signals in the asymptomatic, control, and normal groups. Among 20 patients in the symptomatic group, microembolic signals were detected in 3 patients (15%). The number of emboli ranged from 1 to 6 per 30 minutes. This is the first report of the presence of microembolic signals in acute stroke patients with MCA stenosis.

Acute Disease↗
PubMed2001

The process of informed consent for urgent abdominal surgery.

OBJECTIVES: To assess perceptions of the informed consent process in patients undergoing urgent abdominal surgery. DESIGN: A prospective observational study was carried out using structured questionnaire-based interviews. Patients who had undergone urgent abdominal surgery were interviewed in the postoperative period to ascertain their perceptions of the informed consent process. Replies were compared to responses obtained from a control group undergoing elective surgery, to identify factors common to the surgical process and those specific to urgent surgery. Patients' perceptions of received information were also compared to the information perceived to have been provided by the consent obtainers. SETTING: Gastrointestinal surgical service of a university teaching hospital. PATIENTS: Seventy-four consecutive patients undergoing urgent abdominal surgery and 80 control patients undergoing elective surgery. MAIN MEASUREMENTS: Principal outcome measures were patients perceptions of factors interfering with the ability to give informed consent, assessment of the quality of informed consent and the degree of discussion of the expected outcomes. RESULTS: Forty-nine of the seventy-four (66%) patients undergoing urgent surgery perceived that pain did not affect their ability to give informed consent. Twenty-seven reported an adverse effect of analgesia on the ability to give informed consent. Only 22% of patients undergoing urgent surgery perceived that there had been any discussion of potential side effects and complications of surgery. CONCLUSION: The majority of patients in this series with acute intra-abdominal surgical conditions perceive that they retain the ability to give informed consent for surgery. There is a need for improved discussion of therapeutic options and likely outcomes.

Abdomen, Acute↗