Biomedical subjects
Publications and source records attributed to S H Goh.
Two new 5-oxonoraporphines, 1 and 2, together with three known compounds, ouregidione, 3-methoxycepharadione B, and isoelemicin, have been isolated from the bark of Mitrephora cf. maingayi. Structures of 1 and 2 were determined to be 1,2,3-trimethoxy-5-oxonoraporphine and 1,2-dimethoxy-3-hydroxy-5-oxonoraporphine on the basis of NMR and MS studies.
Isolates from 25 (13 sporadic and 12 outbreak) cryptosporidiosis cases, 24 of which were from British Columbia, Canada, were characterized using nested polymerase chain reaction amplification of the polymorphic internal transcribed spacer 1 locus. Two predominant Cryptosporidium parvum genotypes were found. Twelve (8 sporadic and 4 outbreak) isolates amplified with the cry7/cry21 primer pair and 12 (5 sporadic and 7 outbreak) isolates amplified with the cry7/cryITS1 primer pair. Multi-locus gene analysis using sequence polymorphisms on 3 other loci, i.e., the thrombospondin-related adhesion protein gene, the dihydrofolate reductase gene, and the 18S rRNA gene on 8 (4 outbreak and 4 sporadic) isolates showed non-random association among the human and animal alleles of the 4 different C. parvum gene loci. Associations between these 2 parasite genotypes and different routes of cryptosporidiosis transmission such as zoonotic, anthroponotic, and waterborne transmission were studied using municipal population and agricultural information, as well as detection of C. parvum oocysts in municipal drinking water specimens of the residential communities of sporadic and outbreak cases.
Over a period of sixteen months, 17 cases of submersion injury (encompassing victims of drowning and near-drowning) were attended to at our Accident and Emergency Department at Changi General Hospital. Most of the victims were inexperienced recreational swimmers, and in 6 of them, early bystander cardiopulmonary resuscitation enabled them to recover without severe morbidity. Non-cardiogenic pulmonary oedema with resulting chest infection was the commonest complication in survivors. Most of the episodes occurred in an urban setting in swimming pools without supervision by lifeguards. About two-thirds of the cases were adults over the age of fifteen years. In addition, there were patients in whom submersion injury was associated with more sinister conditions (fits, traumatic cervical spine injury, dysbarism, intoxication from alcohol or drugs), some of which were unsuspected by the doctors initially. Apart from the immediate threats of hypoxia and pulmonary injury, active search for any possible precipitating causes and associated occult injury should be made. In this study, the determinants of survival from near-drowning were early institution of cardiopulmonary resuscitation, presence of pupil reactivity, and presence of a palpable pulse and cardiac sinus rhythm.
It was recently reported that Streptococcus iniae, a bacterial pathogen of aquatic animals, can cause serious disease in humans. Using the chaperonin 60 (Cpn60) gene identification method with reverse checkerboard hybridization and chemiluminescent detection, we identified correctly each of 12 S. iniae samples among 34 aerobic gram-positive isolates from animal and clinical human sources.
A previous study (S. H. Goh et al., J. Clin. Microbiol. 34:818-823, 1996) demonstrated that a 600-bp region of the chaperonin 60 (Cpn60) genes from various bacterial isolates could be amplified by PCR with a pair of degenerate primers and that the products could be used as species-specific probes for Staphylococcus aureus, S. epidermidis, S. haemolyticus, S. lugdunensis, S. saprophyticus, and S. schleiferi. To further validate the utility of bacterial Cpn60 genes as universal targets for bacterial identification (ID), reverse checkerboard chemiluminescent hybridization experiments were performed with DNA probes from 34 different Staphylococcus species and subspecies. With the exception of probes from the Cpn60 genes of S. intermedius and S. delphini, which cross hybridized, all were species specific. Two subspecies of both S. capitis and S. cohnii were differentiated from one another, while DNAs from the two S. schleiferi subspecies cross hybridized. When 40 known Staphylococcus isolates were tested in a blind experiment by the Cpn60 gene method, 36 strains, representing six species and one subspecies (S. sciuri, S. caseolyticus, S. hominis, S. warneri, S. hyicus, S. haemolyticus, and S. capitis subsp. ureolyticus), were correctly identified. DNA from the four remaining isolates, known to be S. hyicus bovine strains, failed to hybridize to DNA from the S. hyicus target strain or any other Staphylococcus species. However, DNAs from these S. hyicus isolates did cross hybridize with each other. New DNA sequence data and evidence from previous studies suggest some genetic divergence between the two groups of S. hyicus isolates. Our results demonstrate that this Cpn60 gene-based ID method has the potential to be a basic method for bacterial ID. Studies are in progress to further validate the utility of this Cpn60 gene system for ID of Staphylococcus and other genera, including those of slow-growing microorganisms.
A set of universal degenerate primers which amplified, by PCR, a 600-bp oligomer encoding a portion of the 60-kDa heat shock protein (HSP60) of both Staphylococcus aureus and Staphylococcus epidermidis were developed. However, when used as a DNA probe, the 600-bp PCR product generated from S. epidermidis failed to cross-hybridize under high-stringency conditions with the genomic DNA of S. aureus and vice versa. To investigate whether species-specific sequences might exist within the highly conserved HSP60 genes among different staphylococci, digoxigenin-labelled HSP60 probes generated by the degenerate HSP60 primers were prepared from the six most commonly isolated Staphylococcus species (S. aureus 8325-4, S. epidermidis 9759, S. haemolyticus ATCC 29970, S. schleiferi ATCC 43808, S. saprophyticus KL122, and S. lugdunensis CRSN 850412). These probes were used for dot blot hybridization with genomic DNA of 58 reference and clinical isolates of Staphylococcus and non-Staphylococcus species. These six Staphylococcus species HSP60 probes correctly identified the entire set of staphylococcal isolates. The species specificity of these HSP60 probes was further demonstrated by dot blot hybridization with PCR-amplified DNA from mixed cultures of different Staphylococcus species and by the partial DNA sequences of these probes. In addition, sequence homology searches of the NCBI BLAST databases with these partial HSP60 DNA sequences yielded the highest matching scores for both S. epidermidis and S. aureus with the corresponding species-specified probes. Finally, the HSP60 degenerate primers were shown to amplify an anticipated 600-bp PCR product from all 29 Staphylococcus species and from all but 2 of 30 other microbial species, including various gram-positive and gram-negative bacteria, mycobacteria, and fungi. These preliminary data suggest the presence of species-specific sequence variation within the highly conserved HSP60 genes of staphylococci. Further work is required to determine whether these degenerate HSP60 primers may be exploited for species-specific microbic identification and phylogenetic investigation of staphylococci and perhaps other microorganisms in general.
Anterior dislocation of the shoulder is the most common dislocation encountered by the emergency room medical officer. Many of the present methods employed, such as Kocher's method, the Hippocratic method and distraction method, necessitate the use of both intravenous pethidine and midazolam, which prolongs the recovery time of the patient in the emergency room, as well as carrying the risk of respiratory depression. Also, such methods are associated with complications such as fractures of the humerus and injury to the axillary vessels and brachial plexus. In view of the above disadvantages, an alternative method of reducing anterior shoulder dislocations was introduced to our emergency room medical officers. For a period of 9 months, the Accident and Emergency Department of Toa Payoh Hospital assessed the method of scapular manipulation for reducing anterior shoulder dislocations. This was a descriptive study. The method was found to have a high success rate (78.4%), was easy to teach, did not rely on the use of strong intravenous sedative agents, and was free of complications. Our experience with this method compared favourably with that of another large series which had a success rate of 79%.
An audit of the accuracy of diagnosis for admitted patients made by the medical officers of the Accident and Emergency Department was carried out recently in Toa Payoh Hospital. This was done for a period of one week lasting from 2nd to 8th February, 1994. A total of 122 admissions were studied and their diagnoses at admission compared with the diagnoses at discharge made by the doctors from the various discipliner in the wards. It was found that a high degree of accuracy of diagnosis was achieved by the medical officers of the Accident and Emergency (A&E) Department for surgical disciplines (82.9% for General Surgery, and 95.8% for Orthopaedic Surgery), and an acceptable degree of accuracy (77.6%) for General Medicine. In addition, the usage of laboratory investigations in the Accident and Emergency Department was also studied. We also assessed the performances of trainees, senior and junior medical officers as well. It is hoped that such an audit will serve to define standards for diagnostic accuracy in the Accident and Emergency Department. This can be a useful tool in the future for measuring and improving the performance of individual Emergency Room medical officers, and also the various Accident and Emergency Departments.
Sebaceous carcinoma of the eyelid, although rare, carries a grave prognosis when diagnosed late. It may be mistaken by the unsuspecting ophthalmologist for a chalazion or chronic blepharoconjunctivitis. Six cases are presented. Three patients were in their fifth decade and the remaining three were over seventy. The latter group presented with advanced local disease and had poorly differentiated tumours. The two oldest patients died of metastasis within 54 months of presentation despite total excision of the lid tumour. This review demonstrates the problems encountered in diagnosis and management.
An audit of unplanned returns by patients to the Accident and Emergency Department was carried out recently in Toa Payoh Hospital. This was done for a period of eleven months for the year 1994. A total of 166 unplanned patient returns were studied. We analysed the reasons for their return, whether there were any differences between the diagnoses made initially and at the return visit, and the outcome of these return visits. It was found that more than two-thirds of patients (72.3%) returned because of a failure to improve from their initial condition even after treatment given by the Emergency Department doctors. The six most common illnesses for which there were failure to improve were asthma, epigastric pains (including gastritis and peptic ulcer disease), gastroenteritis and food poisoning, renal and ureteric colic, minor head injury and backache. Another 14.5% of patients were found to have wrong or missed diagnoses at the initial visit, the two most important of which were appendicitis and bleeding from the gastrointestinal tract. It is hoped that such an audit will serve to identify areas for improvement in patient care. It can also be a useful tool for measuring and improving the performance of individual Emergency Room doctors, or a group of doctors.
We studied 32 patients who presented to the Accident and Emergency Department of Toa Payoh Hospital with injuries sustained while roller-blading (in-line roller skating). This sporting activity carries risk of injuries, often fractures, due to 3 principal mechanisms of injury. The first and main mechanism of injury is that of a forward fall with the arms outstretched as a protective gesture. This is associated with fractures of the distal radius in the majority of cases, although other injuries to the upper limb can occur. The second important mechanism is that of a backward fall with resulting injury to the back of the head. Lastly, the patient may fall sideways, often together with a twisting force to the lower limbs, resulting in ankle sprains and meniscus injuries to the knee. The vast majority of patients are young teenagers who are beginners and had not been properly clad in protective gear. Roller-blading therefore carries a very real risk of sporting injury.
The oxidative susceptibilities of low density lipoproteins (LDL) isolated from rabbits fed high-fat atherogenic diets containing coconut, palm, or soybean oil were investigated. New Zealand white rabbits were fed atherogenic semisynthetic diets containing 0.5% cholesterol and either (i) 13% coconut oil and 2% corn oil (CNO), (ii) 15% refined, bleached, and deodorized palm olein (RBDPO), (iii) 15% crude palm olein (CPO), (iv) 15% soybean oil (SO), or (v) 15% refined, bleached, and deodorized palm olein without cholesterol supplementation [RBDPO(wc)], for a period of twelve weeks. Total fatty acid compositions of the plasma and LDL were found to be modulated (but not too drastically) by the nature of the dietary fats. Cholesterol supplementation significantly increased the plasma level of vitamin E and effectively altered the plasma composition of long-chain fatty acids in favor of increasing oleic acid. Oxidative susceptibilities of LDL samples were determined by Cu2(+)-catalyzed oxidation which provide the lag times and lag-phase slopes. The plasma LDL from all palm oil diets [RBDPO, CPO, and RBDPO(wc)] were shown to be equally resistant to the oxidation, and the LDL from SO-fed rabbits were most susceptible, followed by the LDL from the CNO-fed rabbits. These results reflect a relationship between the oxidative susceptibility of LDL due to a combination of the levels of polyunsaturated fatty acids and vitamin E.
This study tested the hypothesis that treatment with a nonsteroidal anti-inflammatory drug will not alter the hypotensive effect of a dihydropyridine calcium channel antagonist. Fifteen essential hypertensives (ages 58-80 years) had a supine diastolic blood pressure (DBP) < 100 mmHg after 4 weeks monotherapy with nitrendipine 5-20 mg twice daily. They entered a double-blind randomised crossover study in which the addition of indomethacin 25 mg three times daily was compared with placebo in treatment phases each of 4 weeks duration. Subjects were seen weekly and measurements in the last 2 weeks of each phase were compared. Supine blood pressure (mean +/- SE) was higher in the indomethacin phase (158 +/- 4/80 +/- 2) than in the placebo phase (154 +/- 4/76 +/- 3) (p < 0.01 for DBP). In 6/15 (40%) of subjects the increase in supine diastolic blood pressure with indomethacin was > 5 mmHg. Plasma urea was also increased in the indomethacin phase: 7.6 +/- 0.6 mmol/l compared with placebo: 6.3 +/- 0.5 mmol/l (p < 0.001). The study has demonstrated that concurrent treatment with the NSAID indomethacin impairs the blood pressure lowering effect of the dihydropyridine calcium channel antagonist nitrendipine. This increase in blood pressure with indomethacin in subjects treated with nitrendipine may represent either an independent pressor effect of indomethacin or a reduced vasodilator prostanoid contribution to the hypotensive effect of nitrendipine. This blood pressure increase may be sufficient to interfere significantly with clinical blood pressure control in some subjects.
An unusual case of tuberculosis paronychia with skin infection of the big toe was recently seen in a patient returning from Kalimantan. This was complicated by inguinal lymphadenitis and tuberculosis abscess formation. The diagnosis was made on culture of the pus from the abscess and upon biopsy and histological examination of the skin lesion from the toe. The patient responded to surgical treatment and chemotherapy with ethambutol, rifampicin and isoniazid.
Traumatic bronchial rupture is a rarity. Its incidence is about 1.5% to 3% in most series of blunt chest trauma. We report a patient who presented after a road traffic accident with an apparently persistent pneumothorax which failed to respond to emergency treatment. This was later discovered to be due to a traumatic bronchial rupture. It is difficult to diagnose traumatic bronchial rupture, the main reason being that it is often not considered by doctors caring for the patient with blunt chest trauma in the Accident and Emergency Department. Failure to recognise this condition contributes to its high mortality. The authors would like to recommend that emergency bronchoscopy be carried out in patients with blunt chest trauma to exclude this potentially treatable condition. This is especially so if there are suggestive clinical features, such as the presence of extensive and spreading subcutaneous emphysema, pneumomediastinum, pneumothorax, haemoptysis, fractures of the first two ribs and respiratory distress. A history of massive blunt force to the chest wall as a mechanism of injury should also prompt the trauma team to consider the need for emergency bronchoscopy.
Inhibition of tumour promotion by various vitamin E compounds (tocopherols and tocotrienols) and some of their dimers was examined by an in vitro assay utilizing the activation of Epstein-Barr virus (EBV) early antigen (EA) expression in EBV-genome-carrying human lymphoblastoid cells. The results reveal that gamma- and delta-tocotrienols derived from palm oil exhibit a strong activity against tumour promotion by inhibiting EBV EA expression in Raji cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). However, alpha- and gamma-tocopherols and dimers of gamma-tocotrienol or gamma-tocopherol lack this activity.
Tuberculosis of the stomach is a rarity. Its diagnosis is difficult as it is often unsuspected or unrecognised. This is a case report of an elderly man who presented with active upper gastrointestinal tract bleeding. The diagnosis was made postoperatively following gastrectomy for bleeding gastric ulcers. The histological specimens showed caseating epithelioid granulomas with Langerhan's giant cells centrally. The authors reviewed the recent literature on tuberculosis of the stomach, and suggest ways to identify the patients at risk.
This is a case report on a 33-year-old man who had a right orbital tumour which was thought to be a cavernous hemangioma clinically and at the time of surgery. This tumour was shown to be hemangiopericytoma of borderline grade on histological study. The purpose of this paper is to present this rare orbital tumour, especially amongst Asians, which may seem benign at presentation. A review of the literature is done with emphasis on its malignant potential and the recommended mode of treatment.