Biomedical subjects
A Bayat
Publications and source records attributed to A Bayat.
Continuous intravenous versus bolus parenteral midazolam: a safe technique for conscious sedation in plastic surgery.
Conscious intravenous sedation is a safe alternative method to general anaesthesia. We have used a technique of continuously titrated, as opposed to incremental boluses of, intravenous or intramuscular midazolam for conscious sedation, with tumescent adrenaline-lignocaine solution for local anaesthesia, routinely in 421 plastic surgical procedures between 1997 and 2000. All patients were American Society of Anesthesiologists (ASA) class I or II. Conscious sedation was administered through our protocol of continuously titrated doses of midazolam in dextrose saline. The operative field was injected subcutaneously with varying volumes of diluted lignocaine and adrenaline, depending on the anatomical region. Preoperative sedation was administered 1 h before the procedure in the form of an intramuscular injection of pethidine and promethazine (Phenergan). Intraoperatively, a subset of patients received up to four divided diluted doses of pethidine. A preoperative 4 h starvation period pronounced the effect of the sedative. No intraoperative conversions to general anaesthesia were needed, and no sedation complications occurred. No unplanned re-admissions secondary to nausea, prolonged drowsiness or pain were required. All patients who were treated using this technique had an uneventful postoperative course. Hospital stay was substantially shorter than following general anaesthesia, which provided a significant reduction in medical-care expenses and a faster return to work. In conclusion, conscious sedation administered by titrated intravenous midazolam is a well-tolerated, safe, consistent, predictable and effective anaesthetic choice for a variety of plastic surgical procedures, many of which would commonly be performed under general anaesthesia.
Genetic susceptibility to Dupuytren's disease: transforming growth factor beta receptor (TGFbetaR) gene polymorphisms and Dupuytren's disease.
Dupuytren's disease (DD) is a benign fibroproliferative disease of unknown cause. It is a familial condition that commonly affects Caucasians. Genetic studies have yet to identify the genes involved in DD. Transforming growth factor beta (TGFbeta) family members are multifunctional; some play a central role in wound healing and fibrosis. Previous studies have implicated TGFbeta cytokines and receptors in DD. In the light of this evidence, TGFbeta receptors represent candidate susceptibility genes for this condition. In this study, we investigated the association of single nucleotide polymorphisms (SNPs) in TGFbeta receptors one, two and three (TGFbetaRI, RII and RIII) with the risk of DD formation. A polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping novel and known TGFbeta receptor polymorphisms. DNA samples from 183 DD patients and 181 controls were examined. There was a statistically significant difference (p<0.05) in genotype frequency distributions between cases and controls for TGFbetaRI polymorphisms in the recessive model. However, there were no significant difference in genotype or allele frequency distributions between cases and controls for the TGFbetaRII and TGFbetaRIII SNPs.
Implications for Burns Unit design following outbreak of multi-resistant Acinetobacter infection in ICU and Burns Unit.
We reviewed the emergence of 13 cases of multi-resistant Acinetobacter infection in burns patients over a 12-month period. The outbreak was started in a non-burn patient in the intensive care unit (ICU) that spread to burns patients in ICU and then the Burns Unit. The importance of opportunistic infection, potential risk factors, treatment and clinical outcome of Acinetobacter infection in burns patients from this cluster of cases is described. This paper implicates the movement of burns patients and medical equipment between ICU and the Burns Unit in the spread of this infection. Future design of Burn Units should aim to incorporate features to allow the management of all burns cases in one location with all intensive care, burns and theatre facilities built in close proximity.
Rapid denaturing high-performance liquid chromatography (DHPLC) for mutation scanning of the transforming growth factor beta3 gene using a novel proof-reading polymerase.
We have utilized a novel variation on the conventional denaturing high-performance liquid chromatography (DHPLC) technology, which we term rapid DHPLC, combining changes in instrumentation, cartridge technology and analysis conditions to enable significant increases in throughput to be achieved. In addition, the use of a novel proof-reading polymerase for sample amplification with a low misincorporation rate enables simplification of the DHPLC patterns and hence enhanced mutation detection recognition. This scheme for increasing DHPLC throughput has been tested by scanning the transforming growth factor (TGF) beta3 gene for the presence of mutations for which there is limited published or on-line data available regarding the presence of gene polymorphisms. TGFbeta isoforms have multiple roles in cell division, growth, proliferation, transformation and differentiation. TGFbeta3 is a TGFbeta cytokine isoform, and has an important role in embryogenesis, cell differentiation and wound healing. The TGFbeta3 gene consists of seven exons and six introns spanning 43 000 bp of the human genome on chromosome 14q23-24. The rapid DHPLC approach enabled scanning of all seven exons and part of the promoter region (1000 bp upstream from exon 1 in the 5'-flanking regions) of the TGFbeta3 gene in 95 Caucasian individuals in only 8 days, in comparison to the 17 days it would have previously taken. Mutations were clearly identified in the promoter region of the TGFbeta3 gene but were absent from the exonic regions. Understanding the genetic variations affecting the TGFbeta3 gene is important as this molecule has multiple regulatory functions on a variety of cell types.
A novel, triple-function vessel dilator.
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Novel single nucleotide polymorphisms in the 3'-UTR of the TGFbetaRI and TGFbetaRIII genes.
Transforming growth factor beta (TGFbeta) family members are multifunctional cytokines that play a key role in cellular growth, proliferation and differentiation. Transmembrane signalling by TGFbeta occurs via a complex of the serine/threonine kinases TGFbeta type 1 (TGFbetaRI), type 2 (TGFbetaRII), and type 3 (TGFbetaRIII) receptors. Previous studies have implicated TGFbeta receptors (TGFbetaR) in a variety of important hereditary clinical disorders. Mutations of the TGFbetaR genes have been observed in several human cancers. The aim of this study was to identify and confirm novel single nucleotide polymorphisms (SNPs) in TGFbetaRI and RIII and to determine the relative allele and genotype frequencies of these SNPs. SNPs were identified from the examination of sequence alignments held in databases and were confirmed by DNA sequencing. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was devised for genotyping TGFbeta receptor polymorphisms. DNA samples from 91 controls were examined. The observed heterozygosities of TGFbetaRI and TGFbetaRIII gene polymorphisms in the control population were 43 and 33%, respectively, suggesting these SNPs could be useful markers in disease association studies.
Necrotising fasciitis in an infant with congenital insensitivity to pain syndrome.
We present a rare case of necrotising fasciitis in an infant with congenital insensitivity to pain syndrome. The aetiology, diagnosis and management of necrotising fasciitis in children are compared with those in adults. In contrast to adults, children affected by necrotising fasciitis are usually previously healthy and have no predisposing factors. Early diagnosis, intravenous antibiotics and aggressive surgical debridement are mandatory for an optimal outcome.
Genetic susceptibility to keloid disease and transforming growth factor beta 2 polymorphisms.
Keloid disease (KD) is a benign fibroproliferative scarring condition of unknown aetiopathogenesis. There is a familial predisposition to keloid scarring. The genes involved in the pathogenesis of abnormal dermal scarring have yet to be identified. Transforming growth factor beta (TGF beta) is a family of multifunctional cytokines, which play a central role in wound healing and fibrosis. The TGF beta 2 isoform is a member of this cytokine family and has previously been implicated in KD pathogenesis. We tested for an association between KD and two novel polymorphisms within the TGF beta 2 gene: an insertion polymorphism within the 59-untranslated region, 109 base pairs away from the initiation codon, and a single nucleotide polymorphism in exon one. We examined DNA samples from 101 patients with KD and 187 ethnically matched controls. No statistically significant differences in TGF beta 2 genotype or allele frequency distribution were observed between the patients and the controls. We believe this to be the first report of a case-control association study in KD and TGF beta 2 polymorphisms.
Genetic susceptibility in Dupuytren's disease: lack of association of a novel transforming growth factor beta(2) polymorphism in Dupuytren's disease.
The genes involved in the pathogenesis of Dupuytren's disease have yet to be identified. In this study, we tested for an association between Dupuytren's disease (DD) and a novel insertion polymorphism within the 5'-untranslated region (5'-UTR), of the TGFbeta(2) gene. DNA samples from 179 DD patients and 187 ethnically matched controls were examined. There was no statistically significant difference in TGFbeta(2) allele frequency distributions between cases and controls for the TGFbeta(2) polymorphism.
Genetic susceptibility in Dupuytren's disease. TGF-beta1 polymorphisms and Dupuytren's disease.
Dupuytren's disease is a benign fibroproliferative disease of unknown aetiology. It is often familial and commonly affects Northern European Caucasian men, but genetic studies have yet to identify the relevant genes. Transforming growth factor beta one (TGF-beta1) is a multifunctional cytokine which plays a central role in wound healing and fibrosis. It stimulates the proliferation of fibroblasts and the deposition of extracellular matrix. Previous studies have implicated TGF-beta1 in Dupuytren's disease, suggesting that it may represent a candidate susceptibility gene for this condition. We have investigated the association of four common single nucleotide polymorphisms in TGF-beta1 with the risk of developing Dupuytren's disease. A polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping TGF-beta1 polymorphisms. DNA samples from 135 patients with Dupuytren's disease and 200 control subjects were examined. There was no statistically significant difference in TGF-beta1 genotype or allele frequency distributions between the patients and controls for the codons 10, 25, -509 and -800 polymorphisms. Our observations suggest that common TGF-beta1 polymorphisms are not associated with a risk of developing Dupuytren's disease. These data should be interpreted with caution since the lack of association was shown in only one series of patients with only known, common polymorphisms of TGF-beta1. To our knowledge, this is the first report of a case-control association study in Dupuytren's disease using single nucleotide polymorphisms in TGF-beta1.
A novel irrigating vessel dilator for microsurgery.
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Two novel polymorphisms in the human transforming growth factor beta 2 gene.
We have identified two novel polymorphisms in the transforming growth factor beta 2 (TGFbeta2) gene; an insertion in the 5'-untranslated region (5'UTR) and a single nucleotide polymorphism (SNP) in exon 1. A 895-bp fragment was analysed covering part of the 5'UTR and exon 1. Single-strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) products was performed to detect sequence variations. This was followed by the sequencing of samples demonstrating distinct banding patterns. A 4-bp insertion (ACAA) in the 5'UTR and a SNP (G > A) within exon 1 was identified. The 5'UTR polymorphism was found to be common in three Caucasian populations from Spain, Turkey and the UK. Exon 1 polymorphism is rare and results in an R to H amino acid substitution in codon 91. Both polymorphisms may prove useful for investigating possible associations of TGFbeta2 with disease.
Split skin grafting fixation for multiple small burn wound areas. A dual technique using tissue glue and staples.
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Late repair of simultaneous bilateral distal biceps brachii tendon avulsion with fascia lata graft.
A 50 year old rock climber sustained a bilateral rupture of the distal biceps brachii tendons. He retained some flexion power in both arms but minimal supination, being weaker on the non-dominant right side. As the patient presented late, with retraction and shortening of the biceps muscle bellies, reconstruction was carried out using fascia lata grafts on both sides. Because of residual weakness on the left (dominant) side, three further surgical procedures had to be carried out to correct for elongation of the graft. A functionally satisfactory outcome, comparable with that on the right side, was eventually obtained. In summary, bilateral fascia lata grafts to bridge the gap between the retracted biceps bellies and the radial tuberosities were successful in restoring function and flexion power to the elbow. Despite being the stronger side, the dominant arm did not respond as well to the initial surgery. This may be due to overuse of this arm after the operation.
Nasopharyngeal electrode recording of somatosensory evoked potentials as an indicator in brain death.
Median nerve somatosensory evoked potentials were recorded in 28 comatose patients, eight of whom were progressing from coma to eventual brain death and in 11 brain dead patients using electrodes over the scalp, neck and nasopharynx (nasopharyngeal electrode). This recording technique was used to assess the different derivation of brainstem P14 wave activity. It showed that in the midfrontal scalp to the nasopharynx derivation a clear P14 was present in all comatose patients. This component disappeared during the passage from coma to brain death. In a separate group, simultaneous direct recordings in the vicinity of the dorsal column nuclei and with a nasopharyngeal electrode were made in five patients undergoing neurosurgical procedures at the craniocervical junction with the same somatosensory evoked potential monitor. We found that the P14 recorded with the nasopharyngeal electrode in the neurosurgical patients corresponded in latency and morphology with the P14 recorded directly on the surface of the craniocervical junction and more specifically in the vicinity of the nucleus cuneatus. The nasopharyngeal electrode provides non-invasive access to the ventral brainstem at the medullo-pontine level and the disappearance of the P14 shows a clear sign of involvement of the craniocervical junction in brain dead patients. Our study showed that with a simple montage the nasopharyngeal electrode is an effective non-invasive monitor for brainstem activity and can be used as an early diagnostic indicator of brainstem death.
Comparison between enzyme-linked immunosorbent assay and cytotoxic cross-match procedures for detecting IgG anti-donor antibodies.
BACKGROUND: Disadvantages inherent to complement-dependent cytotoxicity cross-match (CDC XM) methods are the requirements for complement and viable target cells, detection of antibodies (Abs) against non-HLA antigens, and subjective scoring. Cross-Stat (SangStat Medical Corp., Menlo Park, CA), a recently developed enzyme-linked immunosorbent assay XM procedure for the detection of IgG anti-donor HLA Abs, is theoretically devoid of these flaws. METHODS: We compared results of Cross-Stat and our standard anti-human globulin (AHG)-enhanced CDC XM procedure on 524 sera from 230 transplant candidates, which were evaluated against 51 cadaveric donors. RESULTS: There was a significant correlation between AHG-CDC IgG XM and Cross-Stat results (P<0.001). For false negative sera, repeat AHG-CDC IgG XMs were still positive after platelet absorption, indicating that the Abs present were either non-HLA Abs or anti-HLA class II. Flow cytometry testing of false positive sera usually (42/62) substantiated Cross-Stat results, indicating that the discrepancy with AHG-CDC IgG XM is caused by greater sensitivity of Cross-Stat. Relative to the AHG-CDC XM, the sensitivity of Cross-Stat was 100%, the specificity was 93%, the positive predictive value was 73%, and the negative predictive value was 100%. A technical shortcoming of the Cross-Stat assay is that the frequency of indeterminate samples in the assays was 15%. Among 49 Cross-Stat negative vs. 13 Cross-Stat positive primary cadaveric renal allograft recipients (all AHG-CDC IgG-XM negative), there was no statistical difference in overall graft survival. CONCLUSION: Given the important theoretical advantages of enzyme-linked immunosorbent assay-based XM methods over the CDC XM, however, further testing of the clinical relevance of the Cross-Stat is warranted.
Involvement of dopaminergic receptor subtypes in straub tail behaviour in mice.
1. Administration of apomorphine to mice induced straub tail behaviour dose-dependently. The response was decreased by the D1 antagonist SCH 23390, the D2 antagonist sulpiride. Reserpine plus alpha-methyl-p-tyrosine (AMPT), caused a marked increase in the response of the drug. 2. The D1 agonist SKF 38393 induced the straub tail behaviour in a dose-dependent manner, which was decreased by SCH 23390, sulpiride or reserpine + AMPT. 3. When animals were administered the D2 agonist quinpirole, a dose-dependent response was produced. This effect was decreased by sulpiride and reserpine + AMPT, but not by SCH 23390. 4. In animals pretreated with reserpine + AMPT, the combination of SKF 38393 with quinpirole produced a significant straub tail behaviour. 5. It is concluded that the concurrent D1/D2 dopamine receptor stimulation is necessary to produce straub tail behaviour in mice.