Mechanistic Insights into Alternative Gene Splicing in Oxidative Stress and Tissue Injury

Significance: Oxidative stress (OS) and inflammation are inducers of tissue injury. Alternative splicing (AS) is an essential regulatory step for diversifying the eukaryotic proteome. Human diseases link AS to OS; however, the underlying mechanisms must be better understood. Recent Advances: Genome‑wide profiling studies identify new differentially expressed genes induced by OS-dependent ischemia/reperfusion injury. Overexpression of RNA-binding protein RBFOX1 protects against inflammation. Hypoxia-inducible factor-1α directs polypyrimidine tract binding protein 1 to regulate mouse carcinoembryonic antigen-related cell adhesion molecule 1 (Ceacam1) AS under OS conditions. Heterogeneous nuclear ribonucleoprotein L variant 1 contains an RGG/RG motif that coordinates with transcription factors to influence human CEACAM1 AS. Hypoxia intervention involving short interfering RNAs directed to long-noncoding RNA 260 polarizes M2 macrophages toward an anti-inflammatory phenotype and alleviates OS by inhibiting IL-28RA gene AS. Critical Issues: Protective mechanisms that eliminate reactive oxygen species (ROS) are important for resolving imbalances that lead to chronic inflammation. Defects in AS can cause ROS generation, cell death regulation, and the activation of innate and adaptive immune factors. We propose that AS pathways link redox regulation to the activation or suppression of the inflammatory response during cellular stress. Future Directions: Emergent studies using molecule-mediated RNA splicing are being conducted to exploit the immunogenicity of AS protein products. Deciphering the mechanisms that connect misspliced OS and pathologies should remain a priority. Controlled release of RNA directly into cells with clinical applications is needed as the demand for innovative nucleic acid delivery systems continues to be demonstrated.

Endoscopic findings among geriatric patients with anaemia and chronic kidney disease at a tertiary teaching hospital in Malaysia

BACKGROUND

Older people with chronic kidney disease (CKD) may be anaemic due to various reasons, and they are vulnerable to various consequences. One of the most important causes of anaemia to be recognised in this population is gastrointestinal loss. The outcome can be improved by early detection, careful investigation, and suitable therapies. There is currently no standardised grading scale or reliable indicators to assist clinicians on handling gastrointestinal workup in elderly CKD patients who are anaemic.

METHODS

A cross-sectional study of 171 people aged 60 and over who had CKD (stages 3-5), including those on Renal Replacement Therapy (RRT) and anaemia. Using oesophagogastroduodenoscopy, colonoscopy, and double balloon endoscopy, we analysed the endoscopic findings and calculated the prevalence of anaemia secondary to gastrointestinal disease. Haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), mean cell haemoglobin (MCH), iron panels, and immuno-faecal occult blood test (iFOBT) were evaluated to predict the diagnostic utility of each parameter in relation to gastrointestinal disorder in the elderly CKD population.

RESULTS

Abnormal endoscopic findings were obtained by upper and lower endoscopy in 98 individuals (57.3%). Upper endoscopy revealed the most prevalent lesions to be gastritis, gastric ulcer, and duodenal ulcer. The upper and lower endoscopies revealed a total of 14.0% malignant and pre-malignant lesions. T-test and receiver-operating characteristic (ROC) curve were performed on all haematological parameters and iron panels. Low ferritin level (less than 100 ng/mL) and combination with low transferrin saturation (less than 20%) have a significant p value less than 0.05. None of these variables had a significant area under the curve (AUC) of more than 0.75.

CONCLUSION

Positive endoscopic findings of anaemia are common in the older population at various stages of CKD, regardless of age, gender, or race. Malignant and premalignant lesions are not uncommon in older CKD patients. In the older CKD population, GI inflammation and ulceration are common lesions. Serum ferritin and TSAT levels are useful indicators of GI disorder in this population. Endoscopic evaluation as part of anaemia workup in the older people with CKD should not be ruled out.

Hepatocellular carcinoma: A local registry on risk factors, imaging patterns, treatment strategies and overall survival

INTRODUCTION

Hepatocellular carcinoma (HCC) is among the common death-causing cancers worldwide. This liver malignancy is primarily diagnosed using radiological imaging techniques. Most of the patients in Malaysia present late and were diagnosed at an intermediate or advanced stage of Barcelona Clinic of Liver Cancer (BCLC). This causes a limitation on the treatment options for the patients.

MATERIALS AND METHODS

We performed a retrospective crosssectional study of HCC cases within a five-year period in our center with data collected from Hospital Canselor Tunku Mukhriz (HCTM). This study examines the HCC risk factors, the pattern of diagnosis, treatment options and overall survival.

RESULTS

The findings from this study showed that viral hepatitis was the highest risk factor in which most of the patients were elderly males who presented with abdominal distension. In addition, given the high prevalence of metabolic diseases Malaysia, it is predicted that the number of non-alcoholic steatohepatosis (NASH)-related HCC cases might increase. Alpha-fetoprotein (AFP) proved to have no significant role in the detection of the disease. The number of patients detected at early BCLC was minimal, resulting in limited options of treatment. Overall survival of our HCC patients was poor at 17 months.

CONCLUSION

We conclude that HCC patients in HCTM mostly presented at late stage to hospital, hence limiting the treatment options and resulted in poor survival rate. Disease awareness should be implemented at primary care level to detect HCC at its early stage. Subsequently, a multidisciplinary hospital team is required to manage the disease at its different stages of presentation.

It's not just a heartburn and reflux disease: a case report of distal oesophageal spasm and review of literature

Distal oesophageal spasm is a rare condition that affects the motility of the oesophagus. It can be diagnosed by highresolution oesophageal manometry and the diagnosis is supported by other modalities such as barium swallow and esophagogastroduodenoscopy examinations. Treatment options include pharmacological therapy, endoscopy and surgical interventions. We described a case of distal oesophageal spasm in an elderly patient who presented with chronic dyspepsia.

Cardiotoxicity risks of adjuvant trastuzumab in Asian breast cancer patients

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Background: Adjuvant trastuzumab (T)-based chemotherapy has been shown to reduce relapse and improve survival in breast cancer patients but has been associated with increased risks of cardiotoxicity. Our study aims to define the incidence and severity of cardiotoxicity amongst Asian breast cancer patients. Methods: This is a retrospective review of patients who have received adjuvant T from June 2005 to 2007. Cardiotoxicity was defined as a drop in left ventricular ejection fraction (LVEF) to less than 50% and/or reduction of > 10% of baseline. Cardiovascular (CVS) risk factors were defined as having a family history or presence of CAD, hypertension, diabetes mellitus, hyperlipidemia and smoking. We used pair sampled t-test to evaluate the mean LVEF change and Chi-square test to evaluate the association of cardiotoxicity and demographics. Results: There were 179 female patients. Cardiotoxicity was reported in 70 (39.1%), of whom 59 had asymptomatic decline in LVEF and 11 experienced CHF. Mean LVEF, comparing various time points (3, 6, 9 and 12 months) against baseline showed statistically significant decline (p<0.05). T was withheld (n=33) due to asymptomatic decline in LVEF (n=24), symptomatic heart failure (n=4) and both (n=5). Twenty-one with resolution of CHF (n=7) or LVEF recovery (n=14) were rechallenged. Cardiotoxicity recurred in 9 - asymptomatic decline in LVEF (n=8) and recurrent CHF (n=1). There were no cardiac-related deaths. Neither patient demographics nor CVS risk factors predicted for cardiotoxicity. Conclusions: This is one of the largest series reported in Asians receiving T. As previously reported, T-induced cardiotoxicity resulted in mostly asymptomatic reversible decline in LVEF. Our incidence of cardiotoxicity appeared higher (39.1%) in Asians and more importantly, almost half of the patients experienced cardiotoxicity upon rechallenge. It would be prudent to explore whether there is any difference in susceptibility to T-induced cardiotoxicity between the different races.

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No significant financial relationships to disclose.

Triple-negative metastatic/recurrent breast cancer: Treatment with paclitaxel/carboplatin combination chemotherapy

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Background: Patients with triple negative (ER, PR, Her2 negative) breast cancers do not derive benefit from Herceptin or hormonal agents. For them, conventional chemotherapy remains the only option. Recent data suggests that triple negative breast cancers (TNBC) have increased sensitivity to platinum agents. We conducted a retrospective analysis to determine the response rates of such patients treated with paclitaxel and carboplatin (TC) chemotherapy. Methods: Patients with metastatic/recurrent TNBC were included in our study. Chemotherapy administered at weekly (paclitaxel 80mg/m2 and carboplatin AUC2 on D1, D8, D15) or 3 weekly intervals (paclitaxel 175mg/m2 and Carboplatin AUC 5 on D1). ER and PR status was defined using IHC. Her 2 positive was defined by a positive FISH or 3+ IHC staining. Results: 101 patients with TNBC were diagnosed at our centre from 2002 to 2005 and of these only 23 patients had metastatic/ recurrent disease. 14 patients were treated with TC and therefore included in our analysis. Median age of patients was 53 yrs (range 36 to 68yrs). 3 patients had metastatic disease at diagnosis and 11 patients were treated for recurrent disease. Median time to recurrence for this subgroup was 20 months (range 8 to 224mths). 4 and 6 patients had prior adjuvant exposure to taxanes and anthracyclines respectively. Median prior lines of chemotherapy was 1 (range 0–4). Median number of disease sites in patients was 4. Eight patients (57%) experience a partial response (PR) with TC. 2 patients had stable disease and 4 progressive disease. Although no patients experienced complete response, 3 patients had good PR. One patient with metastatic disease had complete resolution of a large, 9cm locally invasive breast tumor after 3 cycles of TC. The second had a 90% reduction in volume of a large chest wall recurrence after 2 cycles TC. Patients who had 2 or 3 prior lines of chemotherapy also continued to show response. The median time to tumor progression was 16 weeks (range 4–28 wks). Conclusions: TC gives a high response rate in patients with metastatic/ recurrent TNBC. Patients with prior exposure to taxanes and those with large volume disease showed good response. Randomised trials are underway to compare the TC regimen with non-platinum containing doublets.

No significant financial relationships to disclose.

Group psychoeducation of relatives of schizophrenic patients: two-year experiences

In order to assess the feasibility and acceptability of group psychosocial education for the relatives of schizophrenics in the community, a 2-year project was carried out in two cities: Jinan and Shanghai, China. The completed sample included 682 cases in the experimental group and 366 cases in the control group. The experimental group received group psychotherapy including 14 lectures and five group discussions with conventional services, and the control group had conventional services only. The annual relapse rate in the experimental group was much lower than that in the control group (17.6 and 23.2%, P < 0.01) and the rate of regular work in the experimental group was higher than that in the control group (37.5 and 30.0%, P < 0.05). At the end of the second year, the relatives in the experimental group had less care burden, better mental and physical health status and more knowledge of caring for schizophrenics than those in the control group. This approach was well accepted by both mental health workers and relatives of schizophrenics and the rate of drop-out was 18.4% only during the 2-year period.

[Dose distributions of linac-based radiosurgery for pineal region mass]

The doses of linac convergent-beam irradiations to pineal region were measured in an anthropomorphic phantom. The feasibility of a linac accelerator as a radiosurgery tool to treat small sized intracranial masses was evaluated. The influences of some irradiation parameters on the dose distributions were discussed. Linac-based radiosurgery can result in dose distributions similar to those achieved by gamma knife, so it is another safe and effective treatment technique of neurosurgery. The smaller the aperture is and the greater the irradiation arc travel is, the larger the dose gradient will be and the better the dose distribution will be. The maximum target doses are dependent greatly upon the collimater aperture. The appropriate irradiation arc travel and margin isodose were also discussed.

A novel human DNA polymorphism resulting from transfer of DNA from chromosome 6 to chromosome 16

A cloned minisatellite, termed lambda MS29, that is unusual because it detects two variable loci in human DNA has been isolated. One locus, DNF21S1, located in the terminal region of the short arm of human chromosome 6, is also present in great apes. The second minisatellite locus, DNF21S2, is located interstitially on chromosome 16p11 and is absent both from non-human primates and from some humans. Physical mapping and sequencing show that the second locus has arisen recently in evolution by duplication of a large (greater than 15 kb) segment of chromosome 6 DNA containing a minisatellite and transposition onto chromosome 16 into a member of a novel low-copy-number repetitive DNA family. This unusual duplication/transposition event appears to represent the first example of a human DNA polymorphism arising through DNA-mediated, rather than RNA-mediated, transfer between autosomes.

Sequences flanking the repeat arrays of human minisatellites: association with tandem and dispersed repeat elements

We present DNA sequences flanking cloned hypervariable human minisatellites. In addition to providing confirmatory evidence that minisatellites cluster with other tandem repeats, these flanking sequences contain a high frequency of interspersed repetitive elements. These elements include a retroviral LTR-like sequence, from which one of the minisatellites appears to have expanded, and a recently described short interspersed repeat. We present our own findings concerning this element, in particular that those examples studied do not show significant evolutionary conservation, despite suggestions that the element may have a cis-acting function.

Clustering of hypervariable minisatellites in the proterminal regions of human autosomes

Six of the human minisatellites detected by DNA fingerprint probes have been localized by in situ hybridization to human metaphase chromosomes. These hypervariable loci are not dispersed at random in the human genome, but show preferential, though not exclusive, localization to terminal G-bands of human autosomes. Two of the proterminal minisatellites are very closely linked to other variable loci. Sequence analysis of one of these additional minisatellites suggests that the two linked minisatellites arose by independent amplification of different repeat units. The proterminal regions of human autosomes may therefore be rich in minisatellites, analogous to the pseudoautosomal terminal pairing region of human sex chromosomes that is similarly abundant in hypervariable minisatellites.

Spontaneous mutation rates to new length alleles at tandem-repetitive hypervariable loci in human DNA

Tandem-repetitive minisatellite regions in vertebrate DNA frequently show substantial allelic variation in the number of repeat units. This variation is thought to arise through processes such as unequal crossover or replication slippage. We show here that the spontaneous mutation rate to new length alleles at extremely variable human minisatellites is sufficiently high to be directly measurable in human pedigrees. The mutation rate at different loci increases with variability in accord with the neutral mutation/random drift hypothesis, and rises to 5% per gamete for the most unstable human minisatellite isolated. Mutations are sporadic, occur with similar frequencies in sperm and oocytes, and can involve the gain or loss of substantial numbers of repeat units, consistent with length changes arising primarily by unequal exchange at meiosis. Germline instability must therefore be taken into account when using hypervariable loci as genetic markers, particularly in pedigree analysis and parenthood testing.

Characterization of a panel of highly variable minisatellites cloned from human DNA

Five of the most variable loci detected in human DNA by hybridization with DNA fingerprint probes have been cloned and characterized. Each locus consists of a tandem-repetitive minisatellite, with repeat units ranging in length from 9 to 45 base pairs depending on the locus. All of these cloned minisatellites act as locus-specific hybridization probes, and detect extremely variable Mendelian loci with heterozygosities ranging from 90 to 99%. These five hypervariable loci, together with a previously-isolated minisatellite designated p lambda g3, are dispersed over four autosomes (chromosomes 1, 5, 7 and 12). Syntenic pairs on chromosomes 1 and 7 show no detectable pair-wise linkage, and thus these hypervariable loci show no evidence of clustering within the genome and should provide valuable markers for mapping inherited disease. The locus-specific minisatellites act as very sensitive hybridization probes, and can be pooled to detect several hypervariable loci simultaneously. The applications of these probes in individual identification, paternity testing and analysis of cell chimaerism are discussed, and are illustrated by an analysis of forensic specimens from two victims who had been sexually assaulted and murdered.

Linkage analysis of British and Indian families with Von Recklinghausen neurofibromatosis

Linkage analysis has been undertaken in two British and three South African Indian families with Von Recklinghausen neurofibromatosis. Eleven polymorphic DNA probes were studied, including both random DNA sequences and candidate oncogenes. Although no evidence for linkage of these probes to the disease was detected, substantial exclusion regions were established on six of the chromosomes studied.

Deletion of genes on chromosome 1 in endocrine neoplasia

Recent studies have identified normal cellular DNA sequences which are lost in the development of embryonal and adult tumours. These tumours are thought to arise after a primary mutation in one allele of such a sequence is followed by loss of its normal homologue. In familial cases, the primary mutation is transmitted in the germ line. The secondary mutation may involve a substantial loss of chromosomal material and thus lead to identification of the site of the inherited mutation. We have examined constitutional and tumour genotypes of medullary thyroid carcinomas and phaeochromocytomas which develop in the dominantly inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN2) to locate the predisposing gene in this syndrome. We observed deletion of a hypervariable region of DNA on the short arm of chromosome 1 in seven out of fourteen tumours. Analysis of the parental origin of the deleted allele in two families showed that it was derived from the affected parent in one case, which suggests that the deletion does not reflect the site of the inherited mutation in MEN2. The deleted region is distal to the breakpoint commonly detected in neuroblastomas, which share with the tumours of MEN2 embryological origin from neuroectoderm.

Cloning a selected fragment from a human DNA 'fingerprint': isolation of an extremely polymorphic minisatellite

A large hypervariable DNA fragment from a human DNA fingerprint was purified by preparative gel electrophoresis and molecular cloning. The cloned fragment contained a 6.3 kb long minisatellite consisting of multiple copies of a 37 bp repeat unit. Each repeat contained an 11 bp copy of the "core" sequences, a putative recombination signal in human DNA. The cloned minisatellite hybridized to a single locus in the human genome. This locus is extremely polymorphic, with at least 77 different alleles containing 14 to 525 repeat units per allele being resolved in a sample of 79 individuals. All alleles except the shortest are rare and the resulting heterozygosity is very high (approximately 97%). Cloned minisatellites should therefore provide a panel of extremely informative locus-specific probes ideal for linkage analysis in man.