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Biomedical subjects

J Antony

Publications and source records attributed to J Antony.

At least 19 recordsLinked to original sources
PubMed2001

Dynamics of mononuclear cadmium beta-lactamase revealed by the combination of NMR and PAC spectroscopy.

The two metal sites in cadmium substituted beta-lactamase from Bacillus cereus 569/H/9 have been studied by NMR spectroscopy ((1)H, (15)N, and (113)Cd) and PAC spectroscopy ((111m)Cd). Distinct NMR signals from the backbone amides are identified for the apoenzyme and the mononuclear and binuclear cadmium enzymes. For the binuclear cadmium enzyme, two (113)Cd NMR signals (142 and 262 ppm) and two (111m)Cd PAC nuclear quadrupole interactions are observed. Two nuclear quadrupole interactions are also observed, with approximately equal occupancy, in the PAC spectra at cadmium/enzyme ratios < 1; these are different from those derived for the binuclear cadmium enzyme, demonstrating interaction between the two metal ion binding sites. In contrast to the observation from PAC spectroscopy, only one (113)Cd NMR signal (176 ppm) is observed at cadmium/enzyme ratios < 1. The titration of the metal site imidazole (N)H proton signals as a function of cadmium ion-to-enzyme ratio shows that signals characteristic for the binuclear cadmium enzyme appear when the cadmium ion-to-enzyme ratio is between 1 and 2, whereas no signals are observed at stoichiometries less than 1. The simplest explanation consistent with all data is that, at cadmium/enzyme ratios < 1, the single Cd(II) is undergoing exchange between the two metal sites on the enzyme. This exchange must be fast on the (113)Cd NMR time scale and slow on the (111m)Cd PAC time scale and must thus occur in a time regime between 0.1 and 10 micros.

Bacillus cereus↗
PubMed2001

Infantile-onset paroxysmal dystonia: a diagnostic dilemma.

A 4-year-old boy presented with a history of paroxysmal dystonic posturing since birth. Episodes were triggered by stress, fatigue, and cold. Sleep, for as short as 1 minute, resulted in complete resolution of dystonia. He was developmentally normal, with no focal neurologic deficits. Cerebrospinal fluid, homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) were borderline low. On ictal spectroscopy, there was reduced blood flow to the right temporal region, caudate nuclei, and thalami. The typical infantile form of dystonia is benign, resolving by 2 years of age in an otherwise normal child. Our patient remains symptomatic at 4 years of age.

Brain↗
PubMed2000

The assessment of quality in medical diagnostic tests: a comparison of ROC/Youden and Taguchi methods.

Diagnostic tests are widely used in many areas of modern technological society, but they are of particular importance in medicine, where early and accurate diagnosis can decrease morbidity and mortality rates of disease. How the quality of diagnostic information and decisions should be measured in a meaningful way has become increasingly important in recent years as an abundance of new diagnostic tests have been introduced. A number of seemingly independent indices are studied for evaluating diagnostic performance such as the receiver operating characteristic curves and signal-to-noise ratios. Designing robustness into diagnostic tests can only be achieved by minimizing the variation in the total number of false diagnosis. This article has undertaken a comparison of signal-to-noise ratios developed by Taguchi in quality engineering and system performance in manufacturing industry. A hybrid is also computed and its relevance to physicians as an efficient assessment method is proposed and strongly encouraged.

Decision Support Techniques↗
PubMed2000

The value of partial sleep deprivation as a routine measure in pediatric electroencephalography.

For more than 50 years it has been known that in patients with epilepsy, sleep markedly increases the diagnostic yield of the electroencephalogram (EEG). Sleep deprivation could have an additional activating role. Many laboratories do not use these methods routinely but reserve them for a second EEG if equivocal or negative findings are present in the initial EEG. We studied a regime of routine partial sleep deprivation without the use of hypnotic agents in 396 children younger than age 17 years who were referred for EEG with a diagnosis of epilepsy or suspected epilepsy. Sleep was achieved for the EEG in 77% (96% in the 1 month to 2 year age group, 78% in the 2 to 8 year age group, and in 64% of those more than 8 years old). In a comparison group of 72 children who had not been sleep-deprived, sleep was achieved in 44% (69% of those less than 2 years old, 27% of those between 2 and 8 years of age, and 33% of those older than 8 years). The differences were highly significant. The regime was well tolerated. Routine partial sleep deprivation is a practical and effective method of obtaining sleep and thus maximizing the information obtained from a single EEG.

Adolescent↗
PubMed1999

Surveillance of acute flaccid paralysis in Australia, 1995-97. Australian Paediatric Surveillance Unit.

OBJECTIVE: Acute flaccid paralysis (AFP) surveillance in Australia as part of the World Health Organization (WHO) certification process for polio eradication in the Western Pacific region. METHODS: Active monthly AFP surveillance through the Australian Paediatric Surveillance Unit, from March 1995 to December 1997. RESULTS: Based on 80 cases, the reported overall rate of AFP was 0.73 per 10(5) children < 15 years (below the expected 1 per 10(5)). The major causes of AFP were Guillain-Barré syndrome (51%) and transverse myelitis (19%). According to the WHO virological classification, there was no case of poliomyelitis, 37.5% were 'non-polio' and 62.5% cases were 'polio compatible' due to inadequate stool testing and follow-up. However, case review by an expert panel enabled 95% to be classified as 'non-polio'. CONCLUSION: Australia must improve AFP surveillance to confirm absence of wild poliovirus. Paediatricians can help Australia meet its certification requirements and contribute to the global eradication effort by reporting and investigating all cases of AFP.

Adolescent↗
PubMed1999

Teaching fractional factorial experiments via course delegate designed experiments.

Industrial experiments are fundamental in enhancing the understanding and knowledge of a process and product behavior. Designed industrial experiments assist people in understanding, investigating, and improving their processes. The purpose of a designed experiment is to understand which factors might influence the process output and then to determine those factor settings that optimize the process output. Teaching "design of experiments" using textbook examples does not fully shed light on how to identify and formulate the problem, identify factors, and determine the performance of the physical experiment. Presented here is an example of how to teach fractional factorial experiments in a course on designed experiments. Also presented is a practical, hands-on experiment that has been found to be extremely successful in instilling confidence and motivation in course delegates. The experiment provides a great stimulus to the delegates for the application of experimental design in their own work environment.

Analysis of Variance↗
PubMed1991

Bulbar and pseudobulbar palsy complicating therapy with high-dose cytosine arabinoside in children with leukemia.

Three of 38 children given high-dose cytosine arabinoside therapy developed a previously undescribed complication. Neurological problems are a frequent occurrence in patients given this therapy, particularly cerebellar ataxia, but the development of bulbar and pseudobulbar palsy has not been reported. In two of these cases, it was sufficiently marked for the course of treatment to be curtailed and occurred at a relatively low cumulative dose of the drug. Neurotoxicity can occur at any time using high-dose cytosine therapy.

Adolescent↗
PubMed1991

Benign intracranial hypertension in childhood: a review of 23 patients.

Twenty-three patients with benign intracranial hypertension (BIH) were seen at the Royal Alexandra Hospital for Children, Sydney over an 18 year period to 1988. Age at presentation ranged from 6 months to 13 years and 5 months. The female to male ratio was 2.3:1. The aetiological factors (sometimes multiple) included: chronic middle ear infection, 30%; dural sinus thrombosis, 22%; head injury, 13%; Vitamin A overdosage, 4%; tetracycline exposure, 4%; and no apparent cause, 43%. Headache was the most common presenting symptom occurring in 91% of patients, followed by vomiting in 65% and blurred or double vision in 57%. Papilloedema occurred in 96% of patients, abducens palsy was noted in 48% and visual impairment in 45%. All patients improved clinically after treatment, one with lumbar puncture only. Of 17 patients treated with steroids, 10 patients recovered and seven patients went on to lumboperitoneal shunt. Two patients recovered with steroid and diuretic treatment. Of two patients initially treated with diuretics only, one recovered and one subsequently required a shunt. Only one patient was initially treated with a lumboperitoneal shunt. Three of the shunted patients had shunt block requiring revision. None had permanent visual loss or other significant sequelae. The visual prognosis of BIH in childhood is good. In view of the relatively high complication rate of steroids and shunting, a controlled comparison of steroid vs acetazolamide/diuretic therapy should be undertaken.

Adolescent↗
PubMed1990

Dural tears associated with lumbar burst fractures.

A retrospective review of 817 spinal fracture patients revealed a 7.7% (20 of 258) incidence of dural tears in surgically treated patients. Dural tears were most common in the lumbar burst fractures (10 of 85). Twenty-five percent of patients with lumbar spine burst fractures and a neurologic deficit had a dural tear requiring repair. Eighty-six percent of patients with lumbar burst injuries and dural tears had a neurologic deficit. An initial posterior approach with inspection of the dura and stabilization of the fracture is recommended when treating lumbar burst fractures with a neural deficit.

Dura Mater↗
PubMed1990

Non-contiguous spinal fractures.

A retrospective review of 817 spinal fracture patients revealed a 6.4% (52/817) incidence of non-contiguous spine fractures. Seventy-three per cent of the non-contiguous injuries were comprised of combinations of injuries in the cervical and thoracic regions or in the thoracic and lumbar regions. Forty-five per cent of fractures were a combination of compression fractures, 40% a combination of a compression fracture and a major spine fracture (i.e., one more likely to cause a neurologic deficit), and 15% a combination of major fractures.

Fractures, Bone↗
PubMed1987

Chronic experimental allergic neuritis. An electrophysiological and histological study in the rabbit.

Ten adult outbred New Zealand white rabbits were inoculated with a single multiportal dose of purified bovine peripheral nerve myelin and Freund's adjuvant containing 500 mg of nerve antigen. Seven animals developed chronic relapsing or progressive disease which was followed by clinical examination for 14 months. Electrophysiological studies showed marked slowing of motor conduction velocity, dispersion of the evoked muscle action potential (MAP) and reduction in amplitude of the MAP derived from distal stimulation. Histological examination of the peripheral nervous system showed at 12 months a marked hypertrophic neuropathy in the nerve roots with well developed onion bulbs, active demyelination and a moderate nerve fibre loss. It is suggested that these animals provide a reliable and predictable model for human chronic inflammatory demyelinating polyneuropathy (CIDP) which should prove valuable for therapeutic trials and studies of pathogenetic mechanisms.

Animals↗
PubMed1985

Vascular access for extracorporeal therapy in the rabbit.

A technique allowing short-term blood access for extracorporeal therapy in rabbits is described. The technique utilizes silicone rubber cannulae and teflon vessel tips to construct an externalized carotid-jugular arteriovenous shunt. The insertion procedure takes 1 h and extracorporeal blood flows in excess of 10 ml/min are obtainable for up to 7 days. Blood flow may still be obtained following shunt clotting by insertion of smaller diameter catheters through the arterial cannula. This technique has been successfully used for extracorporeal therapy in rabbit disease models.

Animals↗
PubMed1980

A method of repair of recurrent recto-vesico-prostatic fistula following prostatectomy.

A recto-vesico-prostatic fistula is a rare complication of prostatectomy. Because of its rarity the literature on the subject is scanty and an individual surgeon's experience in the field is limited. Recurrence of such fistulas are common after repair, posing a difficult problem for the surgeon. A method of repair is presented, which is a combination of procedures based on sound surgical principles. This repair also holds a promise of cure for recurrent fistulas.

Colostomy↗