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Biomedical subjects

T K Lim

Publications and source records attributed to T K Lim.

122 records · Page 7Linked to original sources
PubMed1978

Regulation of the biosynthesis of cytochrome P-450 in brewer's yeast. Role of cyclic AMP.

The drug metabolising enzyme cytochrome P-450 has been studied in great detail in mammalian systems and its presence in microorganisms is also well established. However, neither its function nor its means of control in brewer's yeast, Saccharomyces cerevisiae, has been investigated. We demonstrate here using yeast protoplasts that it is the intracellular concentration of cyclic AMP which controls, by repression, the de novo synthesis of the enzyme, and also that cyclic AMP concentrations are in turn inversely related to the concentration of glucose in the yeast growth medium.

Cyclic AMP↗
PubMed1978

Changes in metabolism of major food components in patients with intrathoracic replacement of the oesophagus with the stomach.

In 19 patients in whom the stomach had been used as an intrathoracic replacement after osephagectomy the absorption of fat, carbohydrate and protein was studied. There is no single pattern of disturbance of such absorption. Protein digestion and absorption occur earlier and more rapidly than in normal subjects, probably as a result of accelerated gastric emptying.

Adult↗
PubMed1978

Factors influencing morbidity and mortality in esophageal carcinoma.

In 1977, 152 patients with carcinoma of the esophagus were admitted under our care. The lesions were located from the hypopharynx to the cardiac portion of the stomach. A prospective study was conducted and the results (mortality and morbidity) were analyzed by computer. Resection was possible in 88 patients and a bypass procedure in 15. On exploration in five patients, the disease was found to be so extensive that no further operative procedures were undertaken. The mortality rate was high, hospital deaths being included in the operative mortality statistics. The best results were obtained by applying the Lewis-Tanner one-stage esophagectomy. When the disease was extensive, a bypass procedure using the Kirschner operation and postoperative irradiation was the method of choice. When the general condition of the patient was poor, the best procedure was a staged esophagectomy, with the reconstruction being undertaken at a later date.

Adult↗
PubMed1977

Equilibria involved in prothrombin- and blood-clotting factor X-membrane binding.

The study of prothrombin- and factor X-membrane interaction by light-scattering intensity measurements at 90 degrees is reported. This technique, which uses a fluorometer as a light-scattering photometer, can be applied to measurement of free and membrane-bound protein concentrations, from which equilibrium constants can be obtained. The following equilibria adequately describe the observed properties of prothrombin-membrane interaction (formula: see text) where P and PL are protein and phospholipid, PiCa and PLjCa are the calcium complexes, P'iCa is the protein after undergoing a calcium dependent transition, and P'-PLi+j+mCa is the protein-membrane complex. Several lines of evidence indicate that i, j, and m are interrelated and m decreases to 0 when i and j are saturated. In agreement with this, direct calcium binding measurements indicate m values of 3.2 +/- 1.5 and 1.1 +/- 1.5 at 0.5 and 1.2 mM calcium, respectively. The total number of functional calcium ions in the complex (i + j + m) is 6 to 9 based on Hill coefficients for the reactions and direct calcium binding measurements. In reaction 3, the maximum stoichiometry of calcium per acidic phospholipid is 1:2. While the details of factor X-membrane binding were not determined in quite as great detail, the equilibria (identified) appear the same but a major difference is the calcium concentration needed to initiate protein-membrane binding.

Animals↗
PubMed1977

Structure of the prothrombin- and blood clotting factor X-membrane complexes.

The configuration of the prothrombin- and factor X-membrane complexes was investigated by the technique of quasielastic light scattering. It is concluded that the fragment 1 region of prothrombin is located at one end of the prothrombin molecule and that the membrane binding site is at the tip of the fragment 1 region. Prothrombin binds to the surface of the membrane with no detected penetration into the lipophilic region of the membrane. The remainder of the prothrombin molecule extends radially from the membrane surface with maximum protrusion into solution. Factor X also binds to the membrane at one end of the molecule and extends into solution. Based on the evidence presented here and in other communications [Nelsestuen, G. L., and Lim, T. K. (1977), Biochemistry 16, and Nelsestuen, G. L., and Broderius, M. (1977), Biochemistry 16 (respectively the first and second in a series of three papers in this issue)] a model for prothrombin-membrane interaction is given. Quasielastic light scattering appears to be a valuable new method for studying protein-membrane interactions.

Animals↗
PubMed1977

Clinical study of hemospermia.

Sixty-five cases of hemospermia seen over a ten-year period were reviewed. No specific etiology was disclosed, although renal tuberculosis was seen in 11 per cent of cases, indicating that hemospermia is a self-limiting and benign condition which does not require full urologic investigation.

Adolescent↗
PubMed1976

Carcinoma of the renal pelvis: an analysis of the diagnostic problems in 23 cases.

A series of 23 patients with carcinoma of the renal pelvis is presented. The different presentations are described and discussed, and the difficulties in establishing a preoperative diagnosis are considered. There were 3 squamous cell carcinomas in the series, all of them associated with renal stone and urinary tract infection.

Adult↗
PubMedDate not supplied

Singapore's experience of SARS.

The coronavirus that causes severe acute respiratory syndrome (SARS) is transmitted mainly via respiratory droplets. Typical presenting symptoms are akin to those of ordinary pneumonia. Young patients start with fever, chills, malaise, headache, or myalgia; cough and dyspnoea follow. Older persons and those taking corticosteroids may have neither fever nor respiratory symptoms. Exceptional suspicion is needed to identify SARS early in the illness. During an outbreak, even patients with low suspicion of SARS should be promptly isolated, and all contacts quarantined. Health workers need training in the use of appropriate barriers against droplets and other body fluids. Any fever cluster in patients or carers requires immediate action: discharges, visits, and transfers between wards and hospitals should be stopped. Halting hospital admissions and ten-day quarantine of suspected cases create wide buffer zones. To counter a possible resurgence of SARS, a system of prepared isolation and quarantine facilities is important.

Disease Outbreaks↗