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Biomedical subjects

D Fung

Publications and source records attributed to D Fung.

At least 19 recordsLinked to original sources
PubMed2003

The dental management of adult patients with haemophilia and other congenital bleeding disorders.

The management of adult dental patients with congenital bleeding disorders has caused a considerable number of problems to the dental profession. There is a need to simplify the process and identify what can be safely carried out on a 'shared care' basis in General Dental Practice or the Community Dental Service. Particular problems are discussed with special reference to those requiring hospital care. The Scottish Oral Health Group for Medically Compromised Patients has developed this clinical guidance in conjunction with the Scottish Haemophilia Directors. It is important that dental care is easily available for this group of patients, especially those living at some distance from the regional centres. The aim is to simplify planning dental care for this group of patients and remove a number of myths concerning their management. The hospital departments, both medical and dental, must be available for advice and to arrange for treatment that is inappropriate outside a specialist hospital.

Adult↗
PubMed2001

What do outpatients value most in their anesthesia care?

PURPOSE: To determine what outpatients ranked highest in their anesthesia care and whether anesthesiologists could predict that ranking. METHODS: A 36 item mail-back questionnaire was administered post-operatively to 45 surgical outpatients and to 15 expert anesthesiologists. Respondents were asked to rank the three highest items from each of four lists of nine items representing pre-operative, intra-operative, pre-discharge and post-discharge outpatient anesthesia care. RESULTS: Complete responses were obtained from 30 outpatients and all anesthesiologists. In each phase of their care (pre-operative, intra-operative, pre-discharge and post-discharge), outpatients ranked highest those elements representing information and communication. Physical conditions of care tend to be least valued. Although anesthesiologists were able to predict what patients valued in the pre and post-discharge phases of their anesthesia care (r = 0.85 and 0.91), they undervalued the importance to patients of communication and information in pre-operative and intra-operative care (r = -0.09 and .65). CONCLUSIONS: Our results reinforce the value that patients place in adequate communication and provision of information in all phases of outpatient anesthesia care, a value that may be underappreciated by anesthesiologists.

Anesthesia↗
PubMed2000

A clinical study of child dental anxiety.

Dental fear in children was studied using Rachman's theory of fear acquisition. Sixty children from two age groups (7-10 years, 11-14 years) participated in the project. The children were new patients attending a paediatric consultation clinic for specialised dental treatment. Thirty-one were diagnosed as being clinically anxious regarding dentistry and 29 were found to be nonanxious. Information regarding children's past experiences and present level of anxiety was obtained from the examining dentist, the children and their parents. Mothers were also interviewed and observed to ascertain their own anxieties and behaviour. The results showed that of Rachman's three pathways to fear, conditioning appeared largely responsible for the children's development of dental fear. Children's fear was more strongly associated with subjective experience of pain and trauma than with objective dental pathology. Indirect learning processes were found to be of only minor importance in this study.

Adolescent↗
PubMed2000

Polymorphisms in the CAG repeat--a source of error in Huntington disease DNA testing.

Five of 400 patients (1.3%), referred for Huntington disease DNA testing, demonstrated a single allele on CAG alone, but two alleles when the CAG + CCG repeats were measured. The PCR assay failed to detect one allele in the CAG alone assay because of single-base silent polymorphisms in the penultimate or the last CAG repeat. The region around and within the CAG repeat sequence in the Huntington disease gene is a hot-spot for DNA polymorphisms, which can occur in up to 1% of subjects tested for Huntington disease. These polymorphisms may interfere with amplification by PCR, and so have the potential to produce a diagnostic error.

Adult↗
PubMed1998

Plasma electrolyte and metabolite concentrations associated with pentobarbital or pentobarbital-propofol anesthesia during three weeks' mechanical ventilation and intensive care in dogs.

Propofol and pentobarbital were used for deep sedation during prolonged mechanical ventilation (3 weeks) and nutritional supplementation in 17 clinically normal dogs in an intensive care setting. Tolerance developed to both drugs. Propofol, in combination with pentobarbital, at an infusion rate of 75 micrograms/kg of body weight per minute was preferred. Pentobarbital infusion alone, begun at the rate of 5 to 6 mg.kg-1.h-1, was satisfactory. The combination of both drugs provided smooth, stable anesthesia and required minimal interventions by intensive care unit personnel. Blood gas tensions and electrolyte, parathyroid hormone (PTH), and metabolite concentrations were generally stable throughout, unless condition of the dog deteriorated (e.g., infection, pneumothorax). Hematocrit and red blood cell count decreased with time, likely attributable principally to multiple blood sample collections. White blood cell count, alkaline phosphatase, phosphate, fibrinogen, cholesterol, and triglyceride values increased with time, in association with pentobarbital and the combination of pentobarbital and propofol. Some of these changes appear to have been related to generic responses to stress and inflammation, some to altered metabolism, and some to the lipid solvent of propofol. The increase in triglyceride concentration was greater when propofol was used. Mortality was 47%, with death occurring between days 2 and 18.

Anesthesia, Intravenous↗
PubMed1997

Applications of capillary electrophoresis in DNA mutation analysis of genetic disorders.

AIM: To facilitate DNA mutation analysis by use of capillary electrophoresis. METHODS: The usefulness and applications of capillary electrophoresis in DNA fragment sizing and sequencing were evaluated. RESULTS: DNA mutation testing in disorders such as cystic fibrosis, Huntington disease, alpha thalassaemia, and hereditary fructose intolerance were undertaken effectively. However, sizing the (CAG)n repeat in the case of Huntington disease was a potential problem when using capillary electrophoresis. Separation polymers used in capillary electrophoresis are still in the developmental phase, with improved ones being released regularly. CONCLUSIONS: In the DNA diagnostic setting, capillary electrophoresis is a valuable development because it expands the scope for automation and has useful analytical properties. The potential to perform complex multiplexing within one electrophoresis run facilitates DNA diagnosis. The different mobility of DNA fragments in capillary electrophoresis compared with conventional gel electrophoresis will require, in some circumstances, additional care when results are being interpreted or reported. Capillary electrophoresis is a cheap alternative for combined automated sequencing and fragment analysis that utilises multicolour fluorescence capability. However, in its present form, it is not useful for large scale sequencing.

Costs and Cost Analysis↗
PubMed1991

Fibrinogen depletion and control of permeability in oleic acid lung injury.

To determine if the biphasic pulmonary clearance of aerosolized 99mTc diethylene penta acetate (99mTc-DTPA) observed in oleic acid lung injury represents acute epithelial damage followed by sealing as a result of intra-alveolar fibrin deposition, we examined the effect of fibrinogen depletion. 99mTc-DTPA clearance was assessed in three groups of rabbits: Group 1, normal fibrinogen + oleic acid injury; Group 2, fibrinogen-depleted + oleic acid injury; Group 3, fibrinogen-depleted with no oleic acid injury. In Group 3 animals with no lung injury, the 99mTc-DTPA clearance rate, expressed as k, the percent decrease in thoracic radioactivity, was similar to that previously reported for healthy rabbits (k = 1.16 +/- 0.57%/min, mean +/- SD). Oleic acid administration to Groups 1 and 2 resulted in significantly faster clearance rates, with identical biphasic curves in all animals, irrespective of fibrinogen status. There were no significant differences between either the initial fast phase (k, Group 1 = 5.26 +/- 1.83%/min, Group 2 = 5.70 +/- 1.77%/min) or the subsequent slow phase (k, Group 1 = 1.67 +/- 0.63%/min, Group 2 = 1.57 +/- 0.55%/min, p greater than 0.05). On histologic examination, Groups 1 and 2 showed greater cellular interstitial infiltrate, alveolar edema, and hemorrhage than did Group 3. Fibrinogen depletion plus oleic acid injury resulted in greater alveolar cellular exudate, edema, and hemorrhage than did either oleic acid or fibrinogen depletion alone. We conclude that fibrinogen is not necessary to produce biphasic 99mTc-DTPA clearance in oleic acid lung injury.

Animals↗
PubMed1990

Lung injury in a surfactant-deficient lung is modified by indomethacin.

Repetitive total lung lavage in adult rabbits leads to a reproducible severe surfactant-deficient lung injury. Hypoxemia requiring mechanical ventilation occurs, accompanied by a substantial pulmonary hypertension, a large intra-alveolar protein leak, peripheral neutropenia, and pathological features of marked neutrophil infiltration with extensive hyaline membrane formation. Pretreatment with indomethacin abolishes postlavage pulmonary hypertension, preserves a slightly better lung function with higher arterial PO2, and prevents the postlavage peripheral neutropenia found in untreated animals. Pretreatment with a thromboxane A2 receptor blocker (L 655,240, Merck Frosst, Canada) also completely attenuated pulmonary hypertension, providing evidence that thromboxane A2 mediates pulmonary arterial hypertension after lung lavage. However, specific thromboxane receptor blockade had no other long-lasting beneficial effects on the ongoing injury in this model.

Animals↗
PubMed1989

Measurement of vibration of hand-held tools: weighted or unweighted?

The standards for hand-arm vibration have evolved from research studies in the late 1960s and were based on discomfort and tolerance levels. The lower frequencies were more intolerant and were weighted accordingly. The vascular and neurologic components of the hand-arm vibration syndrome may develop independently, and recent epidemiologic studies have shown both underestimation and overestimation in the incidence of Raynaud's phenomenon from the International Standard Organization dose-response criteria with respect to different tools. The validity of the current International Standard Organization, British Standards Institute, American National Standards Institute, and The American Conference of Governmental Industrial Hygienists Threshold Limit Values is therefore questionable. The weighted and unweighted frequency spectra of various hand-held tools are presented in this paper. It is concluded that, until such time as more dose-effect data become available, unweighted measurements should be determined. Furthermore, the frequencies measured should be extended to 5 kHz.

Arm↗
PubMed1986

Exonuclease III and endonuclease IV remove 3' blocks from DNA synthesis primers in H2O2-damaged Escherichia coli.

Escherichia coli deficient in exonuclease III (xth gene mutants) are known to be hypersensitive to hydrogen peroxide. We now show that such mutants accumulate many more DNA single-strand breaks than do wild-type bacteria upon exposure to H2O2. DNA isolated from H2O2-treated xth- cells contains strand breaks that do not efficiently support synthesis by E. coli DNA polymerase I, indicating the presence of blocking groups at the DNA 3' termini. Purified E. coli exonuclease III activates this blocked DNA to allow substantial synthesis by polymerase I in vitro. Another E. coli enzyme, endonuclease IV, also activates primers for DNA polymerase. Exonuclease III accounts for greater than 95% of the total activity in E. coli crude extracts for removal of 3'-terminal phosphoglycolaldehyde esters from model DNA substrates. Purified exonuclease III and endonuclease IV can each efficiently remove 3'-terminal phosphoglycolaldehyde in vitro. An important physiological function for exonuclease III is thus the activation of blocked 3' ends for DNA repair synthesis. Endonuclease IV can also initiate the repair of ruptured 3'-deoxyribose in DNA.

DNA Damage↗
PubMed1985

Gas chromatographic/mass spectrometric analysis of specific isomers of polychlorodibenzofurans.

The gas chromatographic/mass spectrometric characteristics of 26 congeners of polychlorinated dibenzofurans, previously characterized by specific synthetic routes and by standard spectroscopic techniques, have been evaluated. The electron impact mass spectra are not particularly isomer-specific, though 2,3,7,8-tetrachlorodibenzofuran is distinguishable on this basis from the three other tetrachloro isomers investigated in this work. Positive ion methane chemical ionization mass spectra do show a greater degree of isomer distinction, and are reasonably reproducible. Electron attachment negative ion spectral characteristics are also presented. Preliminary results on negative ion chemical ionization mass spectra, obtained using methane plus small amounts of oxygen as reagent gas, are reported.

Benzofurans↗
PubMed1984

Anaesthesia for caesarean section and cerebral aneurysm clipping.

A pregnant patient at 38 weeks gestation presented for a combined procedure of Caesarean section, tubal ligation and cerebral aneurysm clipping. Anaesthesia was induced with thiopental, succinylcholine was administered to facilitate tracheal intubation, and intravenous lidocaine and sodium nitroprusside were used to reduce the hypertensive response to tracheal intubation. Anaesthesia was maintained with nitrous oxide until delivery of the infant, after which time fentanyl, low-dose halothane and pancuronium were added for maintenance of anaesthesia during the neurosurgical procedure. Blood pressure was controlled during the case by administration of a sodium nitroprusside infusion and propranolol. Following completion of the surgical procedures, the patient promptly emerged from anaesthesia and was neurologically normal in the operating room. It is concluded that general anaesthesia can be used satisfactorily for a combined procedure of Caesarean section and cerebral aneurysm clipping.

Adult↗
PubMed1983

Quantitative analysis of lesion parameters in radiofrequency trigeminal rhizotomy.

A series of 144 lesions made during 32 radiofrequency rhizotomies was reviewed. The parameters of each lesion were compared with the sensory change resulting from the lesion. One-half of the lesions resulted in no sensory change, but 16.7% produced numbness in a division not predicted by stimulation. This was a barely detectable sensory change in 6% of lesions and more dense in 10%. The first lesion in a series was particularly likely to result in sensory deficit, and accounted for half of the more dense lesions not predicted by stimulation. When the threshold at which stimulation was perceived was 0.2 volts or less, a lesion was likely to produce numbness, and when it was 0.5 volts or greater, marked sensory loss did not occur. There was no apparent relationship between the likelihood of sensory change and lesion temperature or duration. Analysis of lesion temperature was made more difficult by the use of low temperatures when numbness should be easy to obtain. With careful technique, radiofrequency rhizotomy can be performed with acceptable risk of unpredicted sensory loss. Particular care should be taken during the first lesion in each procedure and when stimulation thresholds are 0.2 volts or less.

Aged↗