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Biomedical subjects

V Anantharaman

Publications and source records attributed to V Anantharaman.

At least 19 recordsLinked to original sources
PubMed2002

Calcium channel blockers as first line treatment for broad complex tachycardia with right bundle branch block: ingenuity or folly?

OBJECTIVE: To study the response of regular broad-complex tachycardia (BCT) demonstrating right bundle branch block (RBBB) to treatment in the Emergency department (ED). METHODS: Retrospective chart review of management of patients with BCT, RBBB without a history of ischaemic heart disease. A diagnosis of ventricular tachycardia (VT) was made if the ECG showed features such as atrioventricular dissociation, capture or fusion beats or if VT was demonstrated during electrophysiological studies (EPS). RESULTS: A total of 25 patients were eligible. Nineteen patients were given intravenous (IV) calcium channel blockers (either verapamil or diltiazem), as first line treatment. Of these, 18 converted to sinus rhythm and the other one patient subsequently converted with amiodarone. The remaining six patients were given IV adenosine (n=3), lignocaine (n=2) or amiodarone (n=1) as first line treatment but none of them were converted. Of these, four of them converted with IV calcium channel blockers eventually. Of the other two patients, who were both given lignocaine initially, one deteriorated haemodynamically with the use of verapamil and required synchronised cardioversion to convert. The other patient did not respond to amiodarone and synchronised cardioversion but was subsequently converted with verapamil. The difference between the success rate of calcium channel blockers and other anti-arrhythmics is statistically significant (P<0.01 by Fischer's exact method). Fourteen cases had diagnoses of VT, including the two patients given lignocaine. Five cases were found to have supraventricular tachycardia with aberrant conduction. Six cases did not have confirmed diagnoses. CONCLUSION: In patients presenting with BCT and RBBB but without underlying ischaemic heart disease, there is evidence to suggest that calcium channel blockers could effectively be used as the treatment of choice.

Adult↗
PubMed2002

Slow-infusion of calcium channel blockers in the emergency management of supraventricular tachycardia.

OBJECTIVE: To compare the efficacy of verapamil and diltiazem as slow infusions in terminating spontaneous supraventricular tachycardia (SVT) in the emergency department (ED). METHOD: Patients of at least 10 years of age who presented to our ED with regular narrow complex tachycardia not converted with a vagal manoeuvre with an ECG diagnosis of SVT were included. Those who were haemodynamically unstable were excluded. Patients were randomized to undergo either verapamil infusion at a rate of 1 mg/min to a maximum of 20 mg or diltiazem infusion at a rate of 2.5 mg/min to a maximum of 50 mg. RESULTS: Eighty-one patients were randomized to receive verapamil infusion and 80 were randomized to receive the diltiazem infusion. There is no difference in success rate between verapamil (98.8%) and diltiazem (96.3%) infusion. The dose of medication required to convert 25,50 and 75% of SVTs were 4.0,5.0 and 8.0 mg for the verapamil infusion and 10.0,12.5 and 17.5 mg for the diltiazem infusion. There was one complication in each group. CONCLUSION: Calcium channel blockers infusions were safe and efficacious in terminating spontaneous SVT. There was no difference between the success rates of verapamil and diltiazem infusions.

Calcium Channel Blockers↗
PubMed2001

Peptide-N-glycanases and DNA repair proteins, Xp-C/Rad4, are, respectively, active and inactivated enzymes sharing a common transglutaminase fold.

Yeast RAD4, its human ortholog Xp-C and their orthologs in other eukaryotes are DNA repair proteins which participate in nucleotide excision repair through a ubiquitin-dependent process. However, no conserved globular domains that might have shed light on their origin or functions have been reported for these proteins. By using sequence profile analysis, we show that RAD4/Xp-C proteins contain the ancient transglutaminase fold and are specifically related to the recently characterized peptide-N-glycanases (PNGases) which remove glycans from glycoproteins during their degradation. The PNGases retain the catalytic triad that is typical of this fold and are predicted to have a reaction mechanism similar to that involved in transglutamination. In contrast, the RAD4/Xp-C proteins are predicted to be inactive and are likely to only possess the protein interaction function in DNA repair. These proteins also contain a long, low-complexity insert in the globular transglutaminase domain. The RAD4/Xp-C proteins, along with other inactive transglutaminase-fold proteins, represent a case of functional re-assignment of an ancient domain following the loss of the ancestral enzymatic activity.

Amidohydrolases↗
PubMed2001

Regulatory potential, phyletic distribution and evolution of ancient, intracellular small-molecule-binding domains.

Central cellular functions such as metabolism, solute transport and signal transduction are regulated, in part, via binding of small molecules by specialized domains. Using sensitive methods for sequence profile analysis and protein structure comparison, we exhaustively surveyed the protein sets from completely sequenced genomes for all occurrences of 21 intracellular small-molecule-binding domains (SMBDs) that are represented in at least two of the three major divisions of life (bacteria, archaea and eukaryotes). These included previously characterized domains such as PAS, GAF, ACT and ferredoxins, as well as three newly predicted SMBDs, namely the 4-vinyl reductase (4VR) domain, the NIFX domain and the 3-histidines (3H) domain. Although there are only a limited number of different superfamilies of these ancient SMBDs, they are present in numerous distinct proteins combined with various enzymatic, transport and signal-transducing domains. Most of the SMBDs show considerable evolutionary mobility and are involved in the generation of many lineage-specific domain architectures. Frequent re-invention of analogous architectures involving functionally related, but not homologous, domains was detected, such as, fusion of different SMBDs to several types of DNA-binding domains to form diverse transcription regulators in prokaryotes and eukaryotes. This is suggestive of similar selective forces affecting the diverse SMBDs and resulting in the formation of multidomain proteins that fit a limited number of functional stereotypes. Using the "guilt by association approach", the identification of SMBDs allowed prediction of functions and mode of regulation for a variety of previously uncharacterized proteins.

Amino Acid Sequence↗
PubMed2001

TRAM, a predicted RNA-binding domain, common to tRNA uracil methylation and adenine thiolation enzymes.

A previously undetected conserved domain is identified in two distinct classes of tRNA-modifying enzymes, namely uridine methylases of the TRM2 family and enzymes of the MiaB family that are involved in 2-methylthioadenine formation. This domain, for which the acronym TRAM is proposed after TRM2 and MiaB, is predicted to bind tRNA and deliver the RNA-modifying enzymatic domains to their targets. In addition to the two families of RNA-modifying enzymes, the TRAM domain is present in several other proteins associated with the translation machinery and in a family of small, uncharacterized archaeal proteins that are predicted to have a role in the regulation of tRNA modification or translation. Secondary structure prediction indicates that the TRAM domain adopts a simple beta-barrel fold. In addition, sequence analysis of the MiaB family enzymes showed that they share the predicted catalytic site with biotin and lipoate synthases and probably employ the same mechanism for sulfur insertion into their respective substrate.

Adenine↗
PubMed2001

Mass cardiopulmonary resuscitation 99--survey results of a multi-organisational effort in public education in cardiopulmonary resuscitation.

Mass cardiopulmonary resuscitation (CPR) 99 in Singapore was a large-scale multi-organisational effort to increase awareness and impart basic cardiac life support skills to the lay public. Mass CPR demonstrations followed by small group manikin practice with instructor guidance was conducted simultaneously in three centres, four times a day. The exercise enlisted 15 community organisations and received the support of 19 other organisations. Three hundred and ninety-eight manikins and 500 instructors ('I's) were mobilised to teach an audience of 6000 participants ('P's). Two surveys, for 'I's and 'P's were conducted with respondent rates of 65.8% and 50%, respectively. 73.6% of the P-respondents ('P-R's) indicated that they attended the event to increase their knowledge. 66.9% were willing to attend a more comprehensive CPR course. Concerns and perceptions in performing bystander CPR were assessed.

Advertising↗
PubMed2001

The CHASE domain: a predicted ligand-binding module in plant cytokinin receptors and other eukaryotic and bacterial receptors.

A novel, 200-230 amino acid extracellular domain was identified in the plant cytokinin receptor Cre1, in the receptor-histidine kinase DhkA and the adenylyl cyclase Acg from the slime mold Dictyostelium discoideum, and in a variety of other receptor-like proteins from bacteria and eukaryotes. The domain is predicted to bind diverse low molecular weight ligands, such as the cytokinin-like adenine derivatives or peptides, and mediate signal transduction through the respective receptors.

Adenylyl Cyclases↗
PubMed2001

Hospital and emergency ambulance link: using IT to enhance emergency pre-hospital care.

Emergency ambulances traditionally inform receiving hospitals of impending arrival of patients only in instances of load and go situations, which on average constitute less than 5% of ambulance runs. Information transmitted is usually sparse. For all other runs, information is made available only on arrival at the emergency department (ED). There have also been numerous limitations associated with voice transmissions.A comprehensive electronic ambulance case record was created as a pilot project in Singapore between three emergency ambulances and the busiest ED there. All information captured by the ambulance crew, including vital signs information and ECGs was entered or downloaded onto a ruggardised PC in the ambulance and this complete ambulance record was transmitted to the ED. Transmission was wireless via the public mobile data network. A 3-month analysis of this pilot run revealed the following. (1) It was possible to capture a complete ambulance case record electronically at a mean time of 94 s vs 7 min 7 s for the traditional written record. (2) Air transmission time for data was approximately 4 s unless ECG wave forms were also transmitted resulting in transmission times frequently exceeding 60 s. (3) At least 68% of data was transmissible in 75% of Hospital & Emergency Ambulance Link (HEAL) ambulances as opposed to only 25% in less than 5% of non-HEAL ambulances. (4) Paramedics' time in the ED decreased from 15 to 8 min as a result of HEAL. (5) The waiting time for critical care patients to be seen at the ED decreased from 35 to 17 min if brought by HEAL ambulances.(6) The HEAL system was able to effectively prompt paramedics in carrying out critical aspects of treatment in close to 100% of instances. (7) The pilot HEAL system was able to demonstrate a limited amount of automated audit of specific aspects of ambulance runs. Having demonstrated the feasibility of the HEAL system, it is a matter of time before enhanced features such as electronic data collection at patient site, voice activated data entry, transmission of data from site, automated ambulance audits and an enhanced level of professional care in the ambulances become common-place reality.

Ambulances↗
PubMed2000

Effects of Nucleoside Analogs on Native and Site-Directed Mutants of HTLV Type 1 Reverse Transcriptase.

A bacterial assay was developed for testing HTLV-1 reverse transcriptase sensitivity to common nucleoside analog inhibitors in an Escherichia coli strain characterized by a temperature sensitive PolI/RecA deletion phenotype. This genetic complementation assay exploits the ability of HTLV-1 reverse transcriptase to functionally replace these missing activities at nonpermissive temperatures. The four inhibitors tested, dideoxyinosine, dideoxyadenosine, deoxythymidine, and didehydrodeoxythymidine are well-known inhibitors of HIV reverse transcriptase. All except dideoxyadenosine showed a strong activity against HTLV-1 reverse transcriptase with IC(50); in the nanomolar range. Sequence alignments were used to identify amino acid residues in HTLV-1 reverse transcriptase, which correspond to those identified as important for drug-resistance in HIV reverse transcriptase. Mutations of some of these HTLV-1 residues altered the IC(50) for the inhibitors as expected, which suggests that these amino acids have a function in HTLV-1 reverse transcriptase similar to that of their homologs in HIV reverse transcriptase. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Changes in chest electrode impedance.

The Prehospital Defibrillation Program in Singapore has in some cases shown a lower amplitude of ventricular fibrillation (VF) than considered the norm. The electrode skin impedance (ESI) refers to the skin impedance determined between two electrodes placed at specific positions on the body surface. The objective of this prospective study was to measure the ESI of patients at 5 Hz and 2 kHz frequencies, and assess its change with time from the application of electrodes, the difference between the ESI at two different sets of electrode placement positions, and correlation with patient factors. Patients who were 25 years or older and not critically ill had their ESI measured with a modified Heart-Save 911 defibrillator, using signal frequencies at 5 Hz and 2 kHz, at 10 seconds, 1 and 2 minutes after electrodes application. Two sets of positions were used; position 1 where an electrode is placed in the right subclavicular region and another just lateral to the apex beat on the left and position 2, which represents the mirror-image of position 1. Thirty-six each of men and women patients were studied. The mean age and weight were 59.9 +/- 13.5 years and 56.8 +/- 24.1 kg respectively. There was no significant correlation between the ESI and patients' body weight or sex. However, there was a significant decrease in the ESI with time from application of electrodes at both positions (P < .05) with the two different frequencies. The ESI was lower when measured at lower frequencies and higher when taken at higher frequencies, but there was no statistically significant difference between the two mirror-image positions used. Thus, with lower frequency, the electrocardiogram amplitude of VF recorded on the automated external defibrillator could be enhanced.

Adult↗
PubMed2000

The short-stay emergency observation ward is here to stay.

The traditional venue for the management of most medical and surgical emergencies has been the in-hospital environment. It is only when patients have been fully evaluated and treated that they are discharged. The increasing cost of hospital stay and burgeoning cost of health care are forcing the medical profession to consider options where illnesses can be managed on a more ambulatory basis. The objective of this study was to assess the volume, characteristics, and disposition of emergency department (ED) patients who were managed in the Short-Stay Emergency Observation Ward (SSEOW). A retrospective study of all patients managed in the SSEOW at the Singapore General Hospital (SGH) from July 1 to December 31, 1997 was conducted. The ED case-records of all observed patients were reviewed. Demographic data as well as information on duration of stay, provisional diagnoses, investigations performed, treatment rendered, and disposition were collected. A total of 114,586 patients were seen at the ED during the study period. There were 9,126 (7.9%) patients who were observed and 1,756 (19.2% of observed or 1.5% of total ED attendance) were subsequently admitted. The median duration of observation was 5.6 +/- 9.2 hours. The hospitalization rate for male and female patients was almost equal (19.2% versus 19.3%) and those 60 years and older (3,559 or 39.00%) had the highest hospitalization rate (28.0%). The higher the triage priority, the more likely the patient was to be observed and subsequently admitted. Most were observed between 2 to 4 hours (3,288 or 36.0%) and the largest group comprised of those with abdominal complaints (4,115 or 45.1%). Patients with alcohol-related problems were observed the longest (6.7 + 9.8 hours) but had the lowest hospitalization rate (2.6%). The SSEOW allowed a 6.4% savings to direct inpatient admission at SGH. The SSEOW represent a management area for the delivery of short-term and diagnostic care on an ambulatory basis. It is accessible, safe and effective in reducing adions.

Adolescent↗
PubMed2000

Chest impedance: characteristics of local patients.

The Pre-hospital Defibrillation Program in Singapore has in some cases demonstrated a lower amplitude of Ventricular Fibrillation (VF) than considered the norm. The Electrode Skin Impedance (ESI) refers to the skin impedance determined between two electrodes placed at specific positions on the body surface. The objective of this prospective study was to measure the ESI of patients at 5 Hz and 2 kHz frequencies, and assess its change with time from the application of electrodes, the difference between the ESI at two different sets of electrode placement positions and correlation with patient factors. Patients who were 25 years or older and not critically ill had their ESI measured with a modified Heart-Save 911 defibrillator, using signal frequencies at 5 Hz and 2 kHz, at 10 seconds, 1 and 2 minutes after electrodes application. Two sets of positions were used; Position 1 where an electrode is placed in the right infra-clavicular region and another just lateral to the apex beat on the left and Position 2, which represents the mirror image of Position 1. 36 each of male and female patients were studied. The mean age and weight were 59.9 +/- 13.5 years and 56.8 +/- 24.1 kg respectively. There was no significant correlation between the ESI and patients' body weight or sex. However, there was a significant decrease in the ESI with time from application of electrodes at both Positions (p < 0.05) with the two different frequencies. The ESI was lower when measured at lower frequencies and higher when taken at higher frequencies, but there was no statistically significant difference between the two mirror-image positions used. Thus, with lower frequency, the ECG amplitude of VF recorded on the automated external defibrillator could be enhanced.

Adult↗
PubMed2000

Hypotension in acute myocardial infarction patients given streptokinase.

OBJECTIVE: This is a prospective cohort study done over a period of one year to look at hypotension that developed in the local Acute Myocardial Infarction (AMI) patients given Streptokinase (SK). METHOD: Suitable patients with AMI (those with ischaemic chest pain most severe within the last 8 hours, ST-segment elevation and no contraindications) were selected for thrombolysis with SK given as the standard dose of 1.5 mega-units diluted in 100 mls of normal saline and infused over 60 minutes. (Group A). The AMI patients who did not receive SK (Group B), were analysed separately and acted as "controls", as it was not possible to withhold thrombolytic therapy in a group of patients in a completely randomised fashion. The pulse, non-invasive blood pressure and electrocardiogram were monitored and recorded. RESULTS: Of 120 patients analysed, 70 received SK (Group A) and 50 (Group B) did not due to a variety of reasons. There was no statistically significant difference in the sex, age and body weight distribution as well as the initial mean arterial blood pressure (MAP) in the two groups. The MAP showed a statistically significant decrease at 15 minutes (105.6 to 81.4 mmHg, 95%CI: 13.965, 28.178) and 30 minutes (105.6 to 89.6 mmHg, 95%CI: 10.929, 19.814) after the commencement of SK in Group A patients. When analysed separately, the decrease in MAP was also statistically significant at 15 minutes (95%CI: 4.263, 22.014) for those with anterior AMI and both at 15 (95%CI: 19.112, 41.299) and 30 minutes (95%CI: 1.191, 28.716) for those with inferior AMI. There was no statistically significant decrease noted in Group B patients and the door-to-needle time for Group A patients was 37.2+/-6.0 minutes. The SK infusion time for Group A patients who developed hypotension was prolonged to 95.3+/-14.1 minutes. CONCLUSION: Hypotension was more commonly noted in the AMI patients given SK. The MAP tend to decrease in the first 30 minutes after commencing the SK infusion. It is thus possible to conclude that the hypotension was at least partly due to SK and is probably a rate-related phenomenon.

Aged↗
PubMed2000

Island Life.

Explore the source record for details and available documents.

Emergency Medical Service Communication Systems↗
PubMed1999

Emergency medicine in Singapore: past, present, and future.

What began in 1948 as a "Casualty and Outpatient Service" at the Singapore General Hospital grew into the first 24-hour emergency unit in 1964 and has since expanded to the current emergency departments of the 6 public hospitals providing acute 24-hour accident and emergency services with an annual patient load of up to 540,000. In 1984, emergency medicine was recognized as a distinct medical specialty by the Ministry of Health. Five years later, structured academic postgraduate training programs were introduced. In 1990, a specialist training committee for emergency medicine was appointed to oversee the development of advanced training in emergency medicine locally. Seven areas of subspecialization have since been identified and are in various stages of development: emergency cardiac care, emergency trauma care, emergency toxicology, prehospital emergency care, pediatric emergency medicine, disaster medicine, and observation medicine. The achievements in emergency medicine in Singapore can help to provide a model for the future development of emergency medicine in other similar environments.

Emergency Medical Services↗
PubMed1999

Hospital resuscitation of cardiac arrest patients.

Resuscitation of collapsed cardiac patients is often a not-too-successful affair. It has been repeatedly emphasised that the most important aspect of cardiac resuscitation is early access, early recognition of ventricular fibrillation and early defibrillation in patients with ventricular fibrillation. However, the co-ordination of the various phases of cardiac resuscitation itself, which is often forgotten, would need a good organisation so that a systematic assessment of the patient can be done while resuscitation is in progress. In this report, we describe a case of successful prolonged cardiac resuscitation with emphasis on the organisation of resuscitation as well as early defibrillation. We would also like to emphasise that all procedures that were done were performed correctly and their effects on the monitored patient were assessed frequently so as to maximise efficiency, myocardial salvage and patient survival.

Aged↗