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Biomedical subjects

A Lim

Publications and source records attributed to A Lim.

At least 19 recordsLinked to original sources
PubMed2007

Feasibility study on the MammoSite in early-stage breast cancer: initial experience.

The aims of this study were to evaluate the feasibility, practicality, efficacy and safety of the delivery of accelerated partial breast irradiation using the MammoSite for the boost phase. Six patients aged 53-69 years with stage T1N0, T2N0, Grade I-II invasive ductal carcinoma received 9-10 Gy prescribed at 1 cm from the MammoSite balloon surface in two fractions of 4.5-5 Gy 6 h apart. The MammoSite was inserted 20-37 days postoperatively. External beam radiation therapy to the whole breast commenced 1-5 days after accelerated partial breast irradiation. The maximum skin dose ranged from 3 to 9 Gy. The skin-cavity distance ranged from 7 to 19 mm. Local discomfort resolved as the scar healed spontaneously within 3-5 days. No Grade III or higher acute toxicity or local infection was recorded. The ease of insertion and accuracy of dosimetry makes the MammoSite suitable for use in properly selected women with early-stage breast cancer in a trial setting.

Aged↗
PubMed2006

Accuracy of intraoperative frozen section in diagnosis of ovarian tumors.

OBJECTIVE: To determine the accuracy of intraoperative frozen section diagnosis of ovarian tumors according to malignancy status. MATERIAL AND METHOD: From May, 1999 to October, 2004 at Songklanagarind Hospital, a total of 229 ovarian specimens were transferred from the operating room to the Department of Pathology for intraoperative frozen section. All cases of deferred diagnosis and disagreement between frozen and permanent paraffin section were reviewed. RESULTS: Intraoperative frozen section diagnosis of all 229 ovarian specimens revealed 54.1% benign tumors, 8.3% borderline tumors, 30.6% malignant tumors, and 7% deferred diagnoses. The final paraffin section diagnoses revealed 52.4% benign tumors, 9.2% borderline tumors, and 38.4% malignant tumors. Mean tumor diameter of the agreement cases were 12.58 +/- 5.39 cm, disagreement cases were 17.64 +/- 6.83 cm, and deferred cases were 19.33 +/- 6.50 cm. The mean diameter of mucinous tumors was significantly different comparing between disagreement cases to agreement cases and deferred cases to agreement cases. The overall accuracy was 89.7%. Sensitivity was highest in the benign group at 98.2% and lowest in the borderline group at 57.1%. The sensitivity and specificity for benign, borderline, and malignant tumors were 98.2%, 57.1%, 86.1%, and 87.0%, 96.4%, 98.5%, respectively. The Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for benign, borderline, malignant tumors were 89.5%, 63.2%, 97.1% and 97.8%, 95.4%, 92.3%, respectively. CONCLUSION: Intraoperative frozen section diagnosis appears to be an accurate technique for the histopathologic diagnosis of ovarian tumors. However, limitations in use of frozen section must be recognized such as large specimens, especially mucinous subtype. Regular re-evaluation or consultation concerning disagreements between frozen section diagnosis and final permanent paraffin diagnosis should be conducted by both surgeons and pathologists as part of quality assurance to determine the most appropriate intraoperative management for patients with ovarian tumors.

Female↗
PubMed2005

Comparison of complementary and alternative medicine use: reasons and motivations between two tertiary children's hospitals.

AIMS: To compare prevalence, reasons, motivations, initiation, perceived helpfulness, and communication of complementary and alternative medicine (CAM) use between two tertiary children's hospitals. METHODOLOGY: A study, using a face-to-face questionnaire, of 500 children attending the University Hospital of Wales, Cardiff, UK was compared to an identical study of 503 children attending the Royal Children's Hospital, Melbourne, Australia. RESULTS: One year CAM use in Cardiff was lower than Melbourne (41% v 51%; OR = 0.67, 95% CI 0.52-0.85), reflected in non-medicinal use (OR = 0.41, 95% CI 0.29-0.58) and general paediatric outpatients (OR = 0.38, 95% CI 0.21-0.67). Compared to Melbourne, factors associated with lower CAM use in Cardiff included families born locally (father: OR = 0.58, 95% CI 0.44-0.77) or non-tertiary educated parents (mother: OR = 0.54, 95% CI 0.38-0.77). Cardiff participants used less vitamin C (OR = 0.31, 95% CI 0.18-0.51) and herbs (OR = 0.49, 95% CI 0.34-0.71), attended less chiropractors (OR = 0.25, 95% CI 0.06-0.37) and naturopaths (OR = 0.08, 95% CI 0.02-0.33), but saw more reflexologists (OR = 3.33, 95% CI 1.08-10.29). In Cardiff, CAM was more popular for relaxation (OR = 1.92, 95% CI 1.03-3.57) but less for colds/coughs (OR = 0.4, 95% CI 0.27-0.73). Most CAM was self-initiated (by parent) in Cardiff and Melbourne (74% v 70%), but Cardiff CAM users perceived it less helpful (OR = 0.46, 95% CI 0.31-0.68). Non-disclosure of CAM use was high in Cardiff and Melbourne (66% v 63%); likewise few doctors/nurses documented recent medicinal CAM use in inpatient notes (0/21 v 2/22). CONCLUSIONS: The differences in CAM use may reflect variation in sociocultural factors influencing reasons, motivations, attitudes, and availability. The regional variation in use and poor communication highlights the importance of local policy development.

Adolescent↗
PubMed2005

Laparoscopic feeding jejunostomy: a systematic review.

BACKGROUND: Enteral feeding devices have gained popularity since the beneficial effects of enteral nutrition have been clarified. Laparoscopic placement of a feeding jejunostomy is the most recently described enteric access route. In order to classify current surgical techniques and assess evidence on safety of laparoscopic feeding jejunostomy, a systematic review was performed. METHODS: The electronic databases Medline, Cochrane, and Embase were searched. Reference lists were checked and requests for additional or unpublished data were sent to authors. Outcome measures were surgical technique and catheter-related complications. RESULTS: Enteral access for feeding purposes can be effectively achieved by laparoscopic jejunostomy. Laparoscopic jejunostomy can be accomplished by either total laparoscopic or laparoscopic-aided techniques. The most experience was obtained with total laparoscopic placement. Which technique to apply should depend on the surgeon's expertise. Conversion rate is similar to other laparoscopic procedures. Complications can be serious and therefore strict patient selection should be warranted. CONCLUSION: Laparoscopic feeding jejunostomy is a viable method to obtain enteral access with the advantages of minimally invasive surgery.

Humans↗
PubMed2005

Age-related calcium changes, oxyradical damage, caspase activation and nuclear condensation in hippocampal neurons in response to glutamate and beta-amyloid.

Neuronal degeneration increases with age in response to stressors, but the sub-cellular mechanism is unknown, partly because of previous difficulty in studying aged neurons in isolation. We studied the mechanism of enhanced neuronal susceptibility to glutamate and beta-amyloid in terms of condensed nuclei and other upstream events in hippocampal neurons cultured from old rats (24 months) compared to middle-age (10 months) and embryonic rats. Treatment of neurons from old animals with beta-amyloid (or glutamate) produced condensed nuclei 1.5x (2x) more frequently than middle-age and 3x (4x) more frequently than embryonic neurons. In addition to age-related baseline levels of caspase activation, neurons from old animals showed a 50% greater increase in caspase activation compared to middle-age and embryonic neurons. In contrast to glutamate treatment, beta-amyloid caused oxyradical damage as protein carbonyls increased 2-fold higher for old neurons than middle-age and 10-fold higher than embryonic neurons. Contrary to expectations, steady-state calcium levels for adult neurons did not increase in response to beta-amyloid. Overall, these results suggest that aged neurons have an inherent increased susceptibility to beta-amyloid toxicity through an early action of oxyradicals followed by caspase activation and nuclear condensation, a common pathway of apoptosis. Age-related glutamate toxicity involves other steps that lead to nuclear condensation, but neuron responses to calcium influx appear more important to cell death than the amount of influx.

Aging↗
PubMed2005

Does changing the configuration of a motor racing circuit make it safer?

OBJECTIVES: To assess the pattern of injuries presenting to a racing circuit medical centre in two three-year periods before and after two chicanes were built into the track. METHODS: Medical centre records were used to identify all patients assessed during the two time periods. Those referred to hospital were categorised by injury severity into three groups. RESULTS: The proportions of those attending the medical centre that were referred and admitted to hospital were the same in both periods (12-13% and 3% respectively). During the two study periods, the risk of a severe injury for a car driver decreased from 0.1% to 0.03% (p<0.05). For a motorcyclist, similar values were 0% and 0.2% (not significant). CONCLUSIONS: Chicanes have improved the safety of the racing circuit for car drivers, reducing the risk of injury.

Accident Prevention↗
PubMed2005

Factors associated with infection by Pseudomonas aeruginosa in adult cystic fibrosis.

Cross-infection with Pseudomonas aeruginosa is an emerging issue in the care of patients with cystic fibrosis (CF). This study sought to determine the extent of, and patient factors associated with, cross-infection in a tertiary referral adult CF centre. P. aeruginosa isolates were genotyped into two groups between November 2001 and February 2003, using pulsed-field gel electrophoresis after DNA digestion by the SpeI endonuclease, and identified as clustered if there was >80% homology in the macrorestriction profiles. Patient factors and measures of disease severity were identified a priori. In total, 157 out of 227 patients had a P. aeruginosa isolate genotyped. Of these, 94 patients (60%) were infected with clustered genotypes and 47 (30%) were infected with the newly described "Midlands 1" (Md1) genotype. A further 18 patients were infected with the previously identified "Liverpool" genotype and two with the "Manchester" genotype. Logistic regression analysis revealed that the predominant predictor of infection with Md1 was age at the time of referral to the centre, suggesting that infection may have occurred prior to referral in some patients. Md1 demonstrated a relatively benign anti-biogram and did not appear to be associated with more severe disease. In conclusion, the present study provides further evidence of the emerging importance of Pseudomonas aeruginosa cross-infection in cystic fibrosis.

Adult↗
PubMed2004

Effect of intraabdominal pressure elevation and positioning on hemodynamic responses during carbon dioxide pneumoperitoneum for laparoscopic donor nephrectomy: a prospective controlled clinical study.

BACKGROUND: Carbon dioxide (CO2) pneumoperitoneum (PP) increases mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) but decreases stroke volume (SV) and cardiac output (CO). This study evaluated the hemodynamic effects of elevated intraabdominal pressure (IAP) occurring during laparoscopic donor nephrectomy (LDN). METHODS: Twenty-two patients undergoing LDN were investigated and hemodynamic parameters, P(v)CO2) (carbon dioxide partial pressure), and VCO2 (carbon dioxide production) were monitored during the procedure. Before and after PP, IAP was raised from 12 to 20 mmHg and the hemodynamic effects were measured every 30 s. RESULTS: During IAP of 12 mmHg and stable serum CO2, there was no change in SV compared to preinsufflation levels. When IAP was elevated from 12 to 20 mmHg, SV initially decreased (p < 05), followed by an increase in MAP and SVR (p < 0.05). CONCLUSION: This study shows that with the fluid and ventilation protocol used, PP has no significant effect on SV at an IAP of 12 mmHg, whereas increasing IAP to 20 mmHg does. In this study, the hemodynamic effects induced by CO2 PP of 12 mmHg are not due to changes in serum CO2. Compression of the venous system during a PP of 20 mmHg reduces preload, with an subsequent increase in SVR.

Abdominal Cavity↗
PubMed2003

LMO2-associated clonal T cell proliferation in two patients after gene therapy for SCID-X1.

We have previously shown correction of X-linked severe combined immunodeficiency [SCID-X1, also known as gamma chain (gamma(c)) deficiency] in 9 out of 10 patients by retrovirus-mediated gamma(c) gene transfer into autologous CD34 bone marrow cells. However, almost 3 years after gene therapy, uncontrolled exponential clonal proliferation of mature T cells (with gammadelta+ or alphabeta+ T cell receptors) has occurred in the two youngest patients. Both patients' clones showed retrovirus vector integration in proximity to the LMO2 proto-oncogene promoter, leading to aberrant transcription and expression of LMO2. Thus, retrovirus vector insertion can trigger deregulated premalignant cell proliferation with unexpected frequency, most likely driven by retrovirus enhancer activity on the LMO2 gene promoter.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Use of complementary and alternative medicine in children: too important to ignore.

There is evidence that complementary and alternative medicine (CAM) is commonly being used for Australian children, however, at the same time, many doctors have little interest or understanding of the topic. Just as with mainstream treatments, CAM therapies have significant potential for adverse effects and drug interactions. Some of these are potentially serious. The use of CAM therapies in children is not an occasional fringe activity, and evidence suggests its usage will increase further. Whatever one's own views on the role of CAM in childrens health care, the topic is important and it should not be ignored.

Australia↗
PubMed2003

Nerve anastomosis with glue: comparative histologic study of fibrin and cyanoacrylate glue.

The authors report the results of a comparative experimental nerve study, using a biologic tissue glue (fibrin) and a synthetic glue (2-cyanoacrylate) in a rat model. A tension-free repair is necessary with the use of fibrin glue, or gapping may occur, thus limiting the use of the agent in promoting re-neurotization. In addition, the human origin of fibrin and thrombin allow for the possibility of viral transmission. The aim of the study was to verify if the synthetic glue is a viable alternative, or whether it causes cellular and tissue lesions. Their main finding was that the cyanoacrylate causes a foreign-body inflammatory reaction and retractile fibrosis, often reducing the nerve diameter up to two-thirds. Cyanoacrylate glue is thus not recommended for peripheral nerve repair.

Animals↗
PubMed2002

Chronic fatigue syndrome: successful outcome of an intensive inpatient programme.

OBJECTIVE: To study the outcome of adolescents with chronic fatigue syndrome (CFS) following an intensive multi-disciplinary inpatient programme. METHODS: A follow-up questionnaire was distributed to all 57 adolescents who had completed the CFS inpatient programme at the Austin and Repatriation Medical Centre. RESULTS: Forty-two adolescents (74%) returned follow-up questionnaires. Immediately following the programme and up to five years after the programme, the majority of participants had returned to school and were functioning better in terms of physical activity and social interactions as compared with before the programme. Before the programme, 94% of adolescents were attending school half-time or less. Up to 5 years after the programme, 78% of adolescents were attending school full-time or with occasional absences only. CONCLUSIONS: A multidisciplinary inpatient programme for CFS was successful in helping to rehabilitate this group of adolescents who were significantly incapacitated prior to entering the inpatient programme.

Adolescent↗
PubMed2001

Identification and location of a cysteinyl posttranslational modification in an amyloidogenic kappa1 light chain protein by electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry.

Amyloid-deposited light chain (AL) amyloidosis is correlated with the overproduction of a monoclonal immunoglobulin light chain protein by a B-lymphocyte clone. Since the amyloid fibril deposits in AL amyloidosis most often consist of the N-terminal fragments of the light chain, the majority of studies have focused on the determination of the primary structure of the protein, and reducing agents have been used routinely in the initial purification process. In this study, two light chain proteins were isolated and purified, without reduction, from the urine of a patient diagnosed with kappa 1 (kappa1) AL amyloidosis. One protein had a relative molecular mass of 12,000 and the other 24,000. Electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry, in combination with enzymatic digestions, were used to verify the amino acid sequences and identify and locate posttranslational modifications in these proteins. The 12-kDa protein was confirmed to be the N-terminal kappa1 light chain fragment (variable region) consisting of residues 1-108 or 1-109 and having one disulfide bond. The 24-kDa protein was determined to be the intact kappa1 light chain containing a cysteinyl posttranslational modification at Cys214 and disulfide bonds located at Cys23-Cys88, Cys134-Cys194, and Cys214-Cys. The methods used in this report enable high-sensitivity determination of amino acid sequence and variation in intact and truncated light chains as well as posttranslational modifications. This approach facilitates consideration of the effect of cysteinylation on the native protein structure and the potential involvement of this modification in AL amyloidosis.

Amino Acid Sequence↗
PubMed2001

Cross-presentation by dendritic cells of tumor antigen expressed in apoptotic recombinant canarypox virus-infected dendritic cells.

We have investigated the possible usefulness of recombinant canarypox virus (ALVAC) encoding the melanoma-associated Ag, Melan-A/MART-1 (MART-1), in cancer immunotherapy, using a dendritic cell (DC)-based approach. ALVAC MART-1-infected DC express, and are able to process and present, the Ag coded by the viral vector. One consistent feature of infection by ALVAC is that these viruses induce apoptosis, and we show cross-presentation of Ag when uninfected DC are cocultured with ALVAC MART-1-infected DC. Uptake of apoptotic virally infected DC by uninfected DC and subsequent expression of tumor Ag in the latter were verified by flow cytometry analysis, image cytometry, and confocal microscopy. Functional activity was monitored in vitro by the stimulation of a MART-1-specific cytotoxic T cell clone. Heightened efficiency in Ag presentation is evidenced in the 2- to 3-fold increase in IFN-gamma production by the T cell clone, as compared with the ALVAC-infected DC alone. Cocultures of ALVAC MART-1-infected and uninfected DC are able to induce MART-1-specific T cell immune responses, as assessed by HLA class I/peptide tetramer binding, IFN-gamma ELISPOT assays, and cytotoxicity tests. Overall, our data indicate that DC infected with recombinant canarypox viruses may represent an efficient presentation platform for tumor Ags, which can be exploited in clinical studies.

Antigen Presentation↗
PubMed2001

Plate-based dormancy culture system for Mycobacterium smegmatis and isolation of metronidazole-resistant mutants.

Mycobacterium smegmatis is an obligate aerobe. However, growth analyses in oxygen-limited liquid cultures have shown that the bacillus is able to survive anoxia with a half-life of 4 days by shifting down to a drug-resistant, dormant state. Metronidazole is the first lead against dormant bacilli and shows selective toxicity for this physiological state. Here, we report a plate-based dormancy culture system employing anoxic jars for M. smegmatis. Its usefulness for the genetic analysis of dormancy was demonstrated by isolating the first metronidazole-resistant mutants. Highly resistant mutants formed slightly yellow (as opposed to creamy) colonies. Furthermore, high-level metronidazole resistance correlated with an increased half-life of 12 days under anoxic conditions. This suggests a link between metronidazole susceptibility and anaerobic survival.

Anti-Bacterial Agents↗