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Biomedical subjects

C S Chan

Publications and source records attributed to C S Chan.

At least 91 records · Page 5Linked to original sources
PubMed1987

Intravenous regional analgesia with a forearm tourniquet.

Lidocaine 0.5 per cent in a dose of 2 mg X kg-1 was used for intravenous regional analgesia with the tourniquet cuff placed over the forearm. The level of tourniquet cuff pressure employed was the arterial "occlusion pressure" plus 50 mmHg. In 48 normotensive patients successful analgesia was achieved; in seven hypertensive patients, four were pain-free, but the other three required more lidocaine to achieve adequate analgesia. No toxic symptoms and signs were observed. Measurement of serum lidocaine concentrations in 12 patients confirmed the safety of the technique, although small leakage of lidocaine past the inflated forearm tourniquet was detected in some patients.

Adolescent↗
PubMed1984

Hydrocortisone-induced anaphylaxis.

Two patients with asthma developed an anaphylactic reaction after the intravenous administration of hydrocortisone. In both cases, the reaction included the rapid development of airflow obstruction. Previous reports have suggested that the allergenic component may be hydrocortisone itself, rather than the diluents or preservatives. When administering hydrocortisone, one should be aware of the possibility of such a reaction, even though it is uncommon. Although potentially life-threatening, particularly in an asthma sufferer, this reaction should be reversible with prompt recognition and appropriate management.

Aged↗
PubMed1984

Anaesthetic management during repair of tracheo-oesophageal fistula.

A flexible fibreoptic laryngoscope was used to facilitate the passage of a long polyvinyl chloride tracheal tube into the left main bronchus during repair of a tracheo-oesophageal fistula situated near the carina in a patient in whom intubation with a double-lumen endobronchial tube was difficult. Close monitoring of neuromuscular transmission using a peripheral nerve stimulator also contributed to the successful anaesthetic management of this patient.

Anesthesia, Inhalation↗
PubMed1984

Bronchodilator responses to nebulised ipratropium and salbutamol singly and in combination in chronic bronchitis.

A placebo controlled study compared the magnitude and duration of bronchodilatation produced by nebulised salbutamol (5 mg) and ipratropium (0.5 mg) singly and in combination in twenty patients with chronic bronchitis (mean baseline FEV1 was 33% predicted). The onset of action, of both nebulised salbutamol and ipratropium given singly, occurred within 15 min. Both agents produced a similar degree of bronchodilatation. In combination both the magnitude and duration of the bronchodilatation produced was significantly greater than with either agent alone.

Aged↗
PubMed1984

Assessment of the clinical usefulness of nebulised ipratropium bromide in patients with chronic airflow limitation.

The effect of adding nebulised ipratropium bromide to bronchodilator treatment was studied in 20 patients with severe chronic airflow limitation. Maintenance theophylline with or without a steroid preparation was continued and comparison made between placebo, nebulised salbutamol, and a combination of nebulised salbutamol and ipratropium. Although the mean FEV1 values showed the combination to produce a small but significant increase in peak bronchodilatation over the effect of salbutamol alone, there were eight patients in whom no clinically useful improvement occurred. The remaining 12 patients did obtain clinically useful improvement in the magnitude or the duration of bronchodilatation (or both) as a result of the added ipratropium. The conclusion is that individual patients with chronic airflow limitation responded to the addition of nebulised ipratropium bromide in a variable way. Patients who could obtain additional benefit from ipratropium need to be identified by an appropriate reversibility study before its inclusion in their bronchodilator treatment.

Aerosols↗
PubMed1983

A family of Saccharomyces cerevisiae repetitive autonomously replicating sequences that have very similar genomic environments.

We have characterized a family of moderately repetitive autonomously replicating sequences (ARSs) in Saccharomyces cerevisiae. Restriction mapping, deletion studies and hybridization studies suggest that these ARSs, which are probably less than 350 base-pairs in size, share one common feature: each is located close to, but not within, a repetitive sequence (131) of approximately 10(3) to approximately 1.5 X 10(3) base-pairs in length. These ARSs can be divided into two classes (X and Y) by their sequence homology and genomic environments. Each of the class X ARSs is embedded within a repetitive sequence (X) of variable length (approximately 0.3 X 10(3) to approximately 3.75 X 10(3) base-pairs); each of the class Y ARSs is embedded within a highly conserved repetitive sequence (Y) of approximately 5.2 X 10(3) base-pairs in length. Both of these sequences are located directly adjacent to the 131 sequence.

Base Sequence↗
PubMed1983

Organization of DNA sequences and replication origins at yeast telomeres.

We have shown that the DNA sequences adjacent to the telomeres of Saccharomyces cerevisiae chromosomes are highly conserved and contain a high density of replication origins. The salient features of these telomeres can be summarized as follows. There are three moderately repetitive elements present at the telomeres: the 131 sequence (1 to 1.5 kb), the highly conserved Y sequence (5.2 kb), and the less conserved X sequence (0.3 to 3.75 kb). There is a high density of replication origins spaced about 6.7 kb apart at the telomeres. These replication origins are part of the X or the Y sequences. Some of the 131-Y repetitive units are tandemly arranged. The terminal sequence T (about 0.33 to 0.6 kb) is different from the 131, X, or Y sequences and is heterogeneous in length. The order of these sequences from the telomeric end towards the centromere is T-(Y-131)n-X-, where n ranges from 1 to no more than 4. Although these telomeric sequences are conserved among S. cerevisiae strains, they show striking divergence in certain closely related yeast species.

Base Sequence↗
PubMed1982

Pregnancy in patients with prosthetic heart valves: an experience with 45 pregnancies.

Between 1974 and 1981, 27 patients became pregnant after prosthetic heart valve replacement with a total of 45 pregnancies. Four pregnancies terminated in therapeutic abortions. Of the remaining 41 pregnancies, 30 were associated with the use of anticoagulants and 11 not. Haemorrhage related to anticoagulant therapy occurred in one patient. The foetal loss in the group with anticoagulant therapy was 33 per cent (10 abortions) and that in the group without was 9 per cent (one abortion). The use of aspirin and dipyridamole during pregnancy (eight pregnancies) did not appear to threaten the outcome of pregnancy. A total of 30 babies were born alive and 20 per cent of them were light for date. There was no perinatal mortality. The typical warfarin embryopathy was not found. Congenital anomalies in four newborns included congenital hydrocephalus, harelip and complete cleft palate, bilateral accessory auricles and bilateral incurving 5th fingers. Subsequently, all except the newborn with congenital hydrocephalus showed normal developmental milestones.

Abortion, Spontaneous↗
PubMed1981

Electroacupuncture in the treatment of post-traumatic sympathetic dystrophy (Sudeck's atrophy).

Twenty patients with established post-traumatic sympathetic dystrophy were treated with electroacupuncture after physical therapy with or without oral medication had failed to produce satisfactory relief of symptoms. Of these patients 14 (70%) experienced marked and permanent improvement. No complications were encountered. The possible mechanisms involved are discussed.

Acupuncture Therapy↗
PubMed1980

Autonomously replicating sequences in Saccharomyces cerevisiae.

A method is presented for isolating DNA segments capable of autonomous replication from Saccharomyces cerevisiae chromosomal DNA based on the differential transforming ability of autonomously replicating plasmids and nonreplicating plasmids. DNA plasmids that are capable of self-replication in yeast transform yeast spheroplasts at about 1000-fold higher frequency than nonreplicating plasmids. We have cloned from total yeast DNA a number of DNA segments that permit the pBR322 plasmid carrying the yeast LEU2 gene to replicate autonomously. These plasmid clones are characterized by their ability to transform Leu- spheroplasts to Leu+ at a high frequency and their ability to replicate autonomously. Analysis of the insert DNAs carried in some of these self-replicating plasmids divides them into two categories: those that are unique in the yeast genome and those that are repetitive.

DNA Replication↗