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Biomedical subjects

S S Ho

Publications and source records attributed to S S Ho.

At least 19 recordsLinked to original sources

Economic analysis of four triple regimens for the treatment of Helicobacter pylori-related peptic ulcer disease in in-patient and out-patient settings in Hong Kong.

BACKGROUND: One-week triple regimens have been shown to be effective for the treatment of Helicobacter pylori-related peptic ulcer disease. AIM: To conduct an economic analysis of four triple regimens for the treatment of H. pylori-related peptic ulcer disease from the perspective of a public health organization in Hong Kong. METHODS: Records of 200 patients with H. pylori-related peptic ulcer disease, who had previously participated in a randomized comparison of ranitidine bismuth citrate (RBC) with amoxicillin and clarithromycin (RAC), omeprazole with amoxicillin and clarithromycin (OAC), RBC with metronidazole and tetracycline (RMT), or, colloidal bismuth subcitrate with metronidazole and tetracycline (BMT) in either in-patient or out-patient setting were reviewed. RESULTS: Fifty patients were excluded because of incomplete documentation or lack of peptic ulcer. In the out-patient group (n=72), the median direct costs of the RAC group (HK $ 5094) were lower those of the BMT (HK $ 5400), RMT (HK $ 5394), or OAC (HK $ 5440) groups, but the difference was significant only between the RAC and BMT groups (P < 0.05). In the in-patient group (n=78), the median direct costs of the RMT group (HK $ 8524) were significantly lower than those of the OAC (HK $ 13 871) and RAC (HK $ 12 092) groups (P < 0.05), but were similar to those of the BMT group (HK $ 8758). CONCLUSIONS: RAC and RMT are the least costly regimens for out-patient and in-patient treatment, respectively, of H. pylori-related peptic ulcer disease in Hong Kong.

Adolescent↗

Distribution of intranodal vessels in differentiating benign from metastatic neck nodes.

AIM: Recent studies report high accuracy of power Doppler sonography in the differentiation of benign from malignant cervical lymphadenopathy. This study was undertaken to identify which of the parameters used in Doppler sonography of cervical lymph nodes is accurate and readily applicable in routine clinical practice. MATERIALS AND METHODS: We reviewed the power Doppler ultrasound examinations of 50 patients with cytologically proven metastatic nodes from nasopharyngeal carcinoma and 50 patients with proven reactive lymphadenopathy. All the examinations had been performed by an experienced sonologist, and intranodal vascular distribution and resistance were evaluated during real-time ultrasound. Twenty metastatic nodes and 40 reactive nodes were less than 10 mm in maximum transverse diameter. The vascular patterns of lymph nodes were classified into three categories: (1) hilar; (2) capsular; (3) hilar and capsular. The resistive index (RI) and pulsatility index (PI) were measured by spectral Doppler. RESULTS: Although metastatic nodes (RI, 0.81 +/- 0.11; PI, 1.89 +/- 0.89) tended to have higher intranodal vascular resistance than reactive nodes (RI, 0.65 +/- 0.08; PI, 1.07 +/- 0.26), there was considerable overlap of the resistance parameters between benign and malignant nodes. Most of the metastatic nodes showed the presence of capsular vascularity (capsular, 16%; capsular and hilar, 78%), whereas the majority of the reactive nodes showed hilar vascularity (98%), and the difference was significant. CONCLUSION: The distribution of intranodal vascularity appears to be more useful than RI or PI in differentiating benign from malignant cervical lymphadenopathy. It is also easier to evaluate the distribution and the results are therefore readily applicable in routine clinical practice.

Adult↗

Does anybody know how we should measure Doppler parameters in lymph nodes?

AIM: To show how currently described techniques confuse interpretation of Doppler indices in lymph node characterization. MATERIALS AND METHODS: The Doppler indices [resistivity index (RI) and pulsatility index (PI)] were obtained in 35 malignant lymph nodes by colour duplex sonography. Each node was sampled at eight different sites. Data were analysed using our own method, and methods employed in six previous studies. RESULTS: Restistivity index values varied between 0.69 and 0.88 and PI values ranged from 1.28 to 2.34. All but two methods produced different resistance indices (P < 0.05). CONCLUSION: Conflicting results are obtained analysing the same data using different methods. Standardized techniques should be agreed and employed in future studies.

Blood Flow Velocity↗

Degree of ERK activation influences both positive and negative thymocyte selection.

Considerable evidence suggests that the ERK pathway is required for positive but not negative thymocyte selection. Here, we report that ERK is highly activated in double-positive (DP) thymocytes expressing an MHC class I-restricted TCR (P14) in response to negatively selecting conditions, whereas ligands that trigger positive selection induced weaker ERK activation. Biochemical evidence also shows that death by neglect is associated with a further reduction in ERK activation. These findings are consistent with the affinity / avidity model of thymocyte selection. To further examine the role of ERK in negative selection we used the MEK-1 inhitibor, PD98059, a specific pharmacological inhibitor of the ERK pathway. Biochemical data demonstrated a reduction of ERK activity by PD98059 in the presence of the negatively selecting ligand. Analysis of P14 TCR-transgenic fetal thymic lobes cultured with PD98059 under negatively selecting conditions showed impaired clonal deletion of DP thymocytes and a concomitant increase in positive selection of functional mature, TCR(hi) transgenic T cells. This demonstrates that altering ERK activity switched negative to positive selection. Contrary to previous reports that show an exclusive role for ERK signaling in positive selection, our data demonstrate that negative selection is also sensitive to the degree of ERK activation.

Animals↗

Longitudinal colour doppler study of superficial lymph nodes in non-Hodgkin's lymphoma patients on chemotherapy.

AIMS/METHODS: A longitudinal study of 22 malignant lymph nodes by colour Doppler (CD) and/or colour power (CP) ultrasonography was undertaken in 12 non-Hodgkin's lymphoma patients to delineate changes in vascularity, and correlate this response with clinical outcome. RESULTS: Reduced vascularity in response to chemotherapy was shown to be a positive prognostic sign. CONCLUSIONS: More persistent nodal vascularity may signify a less favourable prognosis.

Adult↗

Differentiation of lymphadenopathy in different forms of carcinoma with Doppler sonography.

AIM: The aim of the study was to show whether it may be possible to characterize malignant nodes of different aetiologies with Doppler imaging. Non-Hodgkin's lymphoma (NHL) and nasopharyneal carcinoma (NPC) were used as the models. MATERIALS AND METHODS: A prospective study was undertaken using colour Doppler sonography in 60 enlarged peripheral lymph nodes of 34 patients with either lymphoma or NPC. The vascular distribution, peak systolic velocity (PSV), end diastolic velocity (EDV), resistivity index (RI) and the pulsatility index (PI) of the largest node on each side of the patient were investigated. RESULTS: The vascular distribution was predominantly 'capsular and central' or 'capsular' in 57 nodes, consistent with previous descriptions, but there was no significant difference in the mean PSV (lymphoma: 20.0 cm/s; NPC: 21.86 cm/s;P > 0.05) and mean EDV (lymphoma: 5.95 cm/s; NPC: 5.07 cm/s;P > 0.05). However, significant differences were shown in the mean RI (lymphoma: 0.71; NPC: 0.81;P < 0.05) and mean PI (lymphoma: 1.43; NPC: 1.88;P < 0.05) of these two groups of lymph nodes. CONCLUSIONS: There is significant difference in the Doppler waveform between malignant nodes affected by lymphoma or NPC, suggesting that further differentiation of malignant nodes may be possible.

Adult↗

Preferred technique for blood flow volume measurement in cerebrovascular disease.

BACKGROUND AND PURPOSE: A noninvasive reliable technique that can reveal cerebral blood flow volume could be a valuable tool in screening programs for stroke prevention. In diagnostic ultrasonography, spectral Doppler imaging (SDI) is popular among sonologists and vascular technologists to estimate blood flow volume despite its documented inaccuracy and the availability of the more accurate technique of color velocity imaging (CVI). The aim of the present study was to demonstrate the discrepancy of blood flow volume estimation with CVI and SDI with use of an "internal" standard. METHODS: The common, internal, and external carotid arteries of 50 healthy subjects (22 men, 28 women, age range 19 to 54 years) were examined with CVI and SDI. The total blood flow volume of the internal and external carotid arteries was then compared with the ipsilateral common carotid artery flow. An accurate technique would demonstrate no difference. The difference (expressed as a percent inconsistency) was therefore a measure of the accuracy of the method. RESULTS: The mean+/-SD inconsistency was found to be 10.6+/-8.3% for CVI and 27.9+/-14.3% for SDI. The difference in inconsistency between CVI and SDI in measurement of carotid blood flow volume was statistically significant (P<0.01). CONCLUSIONS: CVI is more accurate than SDI in the determination of blood flow volume in the carotid arteries. For noninvasive clinical estimation of cerebrovascular blood flow volume, CVI quantification should be the preferred technique.

Adult↗

Competitiveness and conflict behavior in simulation of a social dilemma.

This experiment examined the competitive behavior in a seven-choice Prisoner's Dilemma game of 108 adult students (68 women, 40 men) classified as high, average, or low in competitiveness based on their scores on the Competitiveness Index. Participants were then presented one of three preprogrammed response conditions representing (1) Competitive, (2) De-escalating, or (3) Noncompetitive conflict behavior from a simulated opponent. Participants high in competitiveness engaged in more competitive behavior and reported higher satisfaction with the task than those low in competitiveness. As expected, the Competitive conditions elicited more competitive behavior than Noncompetitive conditions. The results suggest competitive individuals may be particularly susceptible to social cues that trigger competitive behavior.

Adult↗

Temporal lobe developmental malformations and hippocampal sclerosis: epilepsy surgical outcome.

BACKGROUND: Temporal lobe developmental malformations coexist with mesial temporal sclerosis in the form of dual pathology with a high frequency of bilateral amygdala or hippocampal abnormalities. OBJECTIVE: The aim of this study was to correlate and compare the MRI findings and the surgical outcome in patients with temporal lobe developmental malformations (n = 20) and isolated mesial temporal sclerosis (n = 36). METHODS: MRI-based normalized volumetry of the amygdala and hippocampal formation in patients with unilateral temporal lobe developmental malformations and isolated mesial temporal sclerosis who underwent temporal lobe resections was performed. Seizure outcome was compared between groups at follow-up. RESULTS: The frequency of bilateral hippocampal or amygdala atrophy (p < 0.04) and combined hippocampal-amygdala atrophy (p < 0.02) was higher in patients with temporal lobe developmental malformations. Although no significant difference in postsurgical seizure-free status was found between the temporal lobe developmental malformations and isolated mesial temporal sclerosis groups (70% versus 91%), patients with temporal lobe developmental malformations and bilateral amygdala or hippocampal-amygdala atrophy had a significantly worse outcome (p < 0.02). CONCLUSION: Bilateral hippocampal atrophy is frequent in patients with temporal lobe developmental malformations. However, it is the presence of bilateral amygdala or amygdalo-hippocampal atrophy that is associated with a higher risk of seizure recurrence.

Adolescent↗

Comparison of laparoscopic sonography with surgical pathology in the evaluation of pelvic lymph nodes in women with cervical cancer.

OBJECTIVE: This study compared laparoscopic sonography with surgical pathology in the evaluation of pelvic lymph nodes in women with cervical cancer. SUBJECTS AND METHODS: Intraoperative laparoscopic sonography of pelvic lymph nodes was performed in 31 women with biopsy-proven cervical cancer. A lymph node that was rounded (longitudinal-transverse axis ratio of <2) or showed absence of central hilum was defined as positive for metastasis. For comparison, lymph nodes from each hemipelvis were grouped anatomically into paraaortic, common, internal, and external iliac chains during evaluation on laparoscopic sonography and on surgical pathologic examination. RESULTS: Pelvic dissection in 31 women yielded 630 lymph nodes. There were 54 metastatic nodes in 12 women. Laparoscopic sonography revealed 32 (59%) of all pathologically metastatic lymph nodes. Sensitivity on laparoscopic sonography when comparing groups by hemipelves was 93.3% and by anatomic lymph node chains was 76.2%. Metastatic nodes were most commonly located in the common iliac region and were characteristically rounded, hypoechoic, showed absence of central hilum, and occasionally showed central necrosis. Nine (28%) of 32 metastatic lymph nodes revealed by laparoscopic sonography measured 1 cm or less. Six benign nodes in four patients were also visualized with laparoscopic sonography. CONCLUSION: Laparoscopic sonography achieved a sensitivity exceeding 90% in the detection of metastatic lymph nodes in the hemipelves of women with cervical cancer. Laparoscopic sonography is a feasible and promising technique for the evaluation of pelvic lymph nodes in women with cervical cancer and merits further evaluation.

Adult↗

Metastatic adenopathy from nasopharyngeal carcinoma: successful response to radiation therapy assessed by color duplex sonography.

BACKGROUND AND PURPOSE: Although the role of gray-scale sonography for neck nodes is well documented, it plays a limited role in the evaluation of nodal response to treatment. This preliminary limited study sought to determine color duplex sonographic changes in successfully treated metastatic nodes from nasopharyngeal carcinoma. METHODS: Fourteen patients with nodal metastases from nasopharyngeal carcinoma were studied. A pretreatment sonogram was obtained for all patients. Patients were divided into two groups of seven: in one group, repeat sonograms were obtained 8 weeks after completion of treatment; in the second group, sonograms were obtained 16 weeks after treatment. The features studied included distribution of intranodal vascularity, resistive and pulsatility indexes, and peak systolic velocity. In 11 patients, follow-up sonograms were obtained 1 year after treatment. RESULTS: The majority (90%) of malignant nodes from nasopharyngeal carcinoma have an increased central and peripheral vascularity, a high resistive index (0.8), and a high pulsatility index (1.8). After radiation therapy to the nodes, a reduction in intranodal vascularity and a statistically significant reduction in the resistive index (0.58 to 0.59) and pulsatility index (0.91 to 0.93) are found. Although a similar reduction in the peak systolic velocity is observed, it is not statistically significant. CONCLUSION: Our preliminary findings suggest that after radiation therapy for malignant nodes in nasopharyngeal carcinoma, a reduction in intranodal vascularity is found, and the resistive and pulsatility indexes may return to benign parameters as early as 8 weeks after completion of treatment.

Adult↗

Normal fetal thyroid volume.

A prospective study of 289 normal fetal thyroids was undertaken between 20 and 36 weeks of gestation in 289 mothers without any history of thyroid disease or maternal disease that could cause intrauterine growth restriction. The fetal thyroid volume was calculated by the ellipsoid equation, with the assumption that each lobe was an ellipse. A nomogram relating fetal thyroid volume to gestational age was established. The mean fetal thyroid volume was found to be 0.23 +/- 0.18 cm3 (median 0.17 cm3; range 0.022-0.85 cm3). The ratio of fetal thyroid volume to estimated fetal weight (V/W ratio) (at 0.163 +/- 0.079 cm3/kg) was constant throughout gestation. The value was smaller than those of the child and the adult reported in other studies, indicating that fetal thyroid enlargement is likely to be underestimated if based on postnatal criteria. It was found that the mean fetal thyroid volume was significantly correlated with estimated fetal weight and gestational age, in which the former dominated the effect. The fetal thyroid increased in size much faster after 32 weeks, suggesting that evaluation of possible fetal goiter should take into account gestational age and the nomogram developed in this study.

Body Weight↗

Pleural fluid pseudouridine in malignant and benign pleural effusions.

Pseudouridine in urine and plasma has been proved to be a useful tumour marker in many malignant conditions. We studied its usefulness in pleural fluid for distinguishing malignant from non-malignant pleural effusions. Pleural fluid pseudouridine concentrations in different groups of patients with pleural effusion (31 malignant, 29 benign, 16 unknown, 1 double pathology) was measured and compared. Its usefulness in distinguishing malignant from non-malignant pleural effusions was analysed by receiver-operating characteristic (ROC) curve analysis. Pseudouridine concentrations in the malignant group were significantly higher than the non-malignant group (P < 0.017, Bonferroni adjustment) with values overlapping extensively at the lower end. The area-under-the curve (AUC) value in the ROC curve analysis was 0.675 (P < 0.05). We conclude that the pleural fluid pseudouridine is of limited clinical value in distinguishing malignant from non-malignant pleural effusion due to its extensive overlap. However, it is useful when the concentration is higher than 65 mumol/L, which indicates malignancy.

Area Under Curve↗

Temporal lobe developmental malformations and epilepsy: dual pathology and bilateral hippocampal abnormalities.

Temporal lobe developmental malformations (TLDM) with focal cortical dysplasia and balloon cells may coexist with mesial temporal sclerosis. The true incidence of this dual pathology is unknown. Our aim was to assess the frequency of amygdala (AM)-hippocampal abnormality in a homogeneous population with this specific developmental malformation. MRI-based volumetry of the AM and hippocampal formation (HF) in 30 patients with unilateral TLDM and intractable partial epilepsy was performed. A volume normalization process defined a normal range of HF and AM volumes in control subjects, and enabled the detection of bilateral volume loss. Normalized volumes detected HF atrophy in 26 patients (nine unilateral and 17 bilateral) and AM atrophy in 18 patients (three unilateral and 15 bilateral). Visual analysis detected unilateral HF abnormality in 21 patients and bilateral abnormality in two. When compared with a group of patients with temporal lobe epilepsy and pure hippocampal sclerosis (N = 92), where volumetry revealed bilateral HF atrophy in 18%, a significant difference in the frequency of bilateral HF atrophy was found (p < 0.0001). Dual pathology is frequent in patients with TLDM (87%), and the AM-HF abnormality is often bilateral (57%). Our data suggest that more widespread and potentially epileptogenic lesions coexist with visibly detectable unilateral TLDM. This has implications for the selection of patients for temporal lobe surgery and may influence surgical strategies.

Adolescent↗

Amygdala atrophy and seizure outcome after temporal lobe epilepsy surgery.

Surgical outcome in hippocampal atrophy (n = 44) and amygdalohippocampal atrophy (n = 14) were compared. Hippocampal atrophy had better seizure-free outcome than amygdalohippocampal atrophy (80% versus 50%, p = 0.043). Severity of hippocampal atrophy correlated with duration of epilepsy in patients with hippocampal atrophy (r = 0.4, p = 0.007), but not in those with amygdalohippocampal atrophy, suggesting that these two groups may have a different pathogenesis.

Amygdala↗

Intraoperative laparoscopic sonography for improved preoperative sonographic pathologic characterization of adnexal masses.

This study compares the diagnostic accuracy of laparoscopic sonography and transvaginal sonography in the evaluation of adnexal masses. Fifty-eight women underwent transvaginal sonography, which showed 69 adnexal masses, and laparoscopic ultrasonography, which showed 68 adnexal lesions. Conventional gray-scale ultrasonography (using transvaginal sonography and laparoscopic ultrasonography) was performed with morphologic characterization of internal architecture, followed by color Doppler imaging with spectral Doppler analysis where possible. A specific diagnosis was obtained with transvaginal sonography and laparoscopic ultrasonography based on a combination of imaging features. The specific diagnosis obtained with each imaging modality was compared with the final histologic diagnosis as the gold standard in 57 patients with 68 adnexal masses who underwent cystectomy or oophorectomy. The ability of laparoscopic sonography to detect the contralateral ovary and any residual ovarian tissue in the presence of a mass was also compared with transvaginal sonography. The accuracy of laparoscopic ultrasonography in the characterization of adnexal masses was 83.8% and that of transvaginal sonography was 73.5% (P < 0.05). Laparoscopic sonography showed greater morphologic detail than that obtained with transvaginal sonography, allowed more precise and specific characterization of adnexal masses, and detected additional adnexal lesions not evident on preoperative transvaginal sonography. Laparoscopic ultrasonography showed the contralateral ovary in 86.2% of patients, compared with 81.0% using transvaginal sonography (P = 0.51). In addition, laparoscopic ultrasonography was able to demonstrate the presence of residual ovarian tissue in the side affected pathologically in 76.5% of patients compared with 59.4% using transvaginal sonography (P < 0.005). Laparoscopic sonography allows more precise morphologic characterization of internal architecture and histologic diagnosis of adnexal lesions, but it is as yet unable to increase the diagnostic accuracy of borderline or malignant lesions, possibly due to the small sample size. Laparoscopic sonography is superior to transvaginal sonography in the evaluation of residual ovarian tissue in the side affected pathologically, which may help in surgical planning between cystectomy and oophorectomy, and also in the identification of the contralateral ovary, which may potentially increase the detection of bilateral pathologic conditions.

Adnexal Diseases↗

Congenital porencephaly: MR features and relationship to hippocampal sclerosis.

PURPOSE: We determined the frequency of amygdalar-hippocampal atrophy in patients with congenital porencephaly-related seizure disorders to ascertain whether specific MR features of the porencephaly correlate with amygdalar-hippocampal atrophy and epilepsy. METHODS: We studied brain MR images of 22 patients with congenital porencephaly and measured the volume of the amygdala, the hippocampal formation, and the porencephalic cyst. We then compared imaging features with seizure symptoms. RESULTS: Porencephaly was unilateral in 20 patients and bilateral in two. Eighteen patients had cortical or subcortical cavitation and four had encephaloclastic changes (noncircumscribed parenchymal destruction associated with cystic components). The porencephaly was located in the middle cerebral artery territory in 12 patients, in the posterior cerebral artery in four, in the internal carotid artery in two, and in multiple vessels in four. The volume of the porencephalic cyst ranged from 1% to 32% of total intracranial volume (mean, 11%). Volumetry detected atrophy of the hippocampal formation in 21 cases (11 unilateral, 10 bilateral) and atrophy of the amygdala in 12 (nine unilateral, three bilateral). No correlation was found between size or location of the porencephaly and degree of hippocampal atrophy. Seizure symptoms correlated with mesial temporal origin but not with cyst location. CONCLUSION: Amygdalar-hippocampal atrophy often coexists with congenital porencephaly (95%), and the atrophy may be bilateral despite unilateral cysts. Hippocampal structures should be carefully assessed in patients with porencephaly-related seizures.

Adolescent↗