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Biomedical subjects

J Lim

Publications and source records attributed to J Lim.

At least 235 records · Page 13Linked to original sources
PubMed1984

Captopril in congestive heart failure resistant to other vasodilators.

In an attempt to study the possible mechanism(s) by which captopril controls resistant heart failure, sequential haemodynamic studies (radioisotope technique) and humoral measurements (plasma renin activity, plasma aldosterone and plasma catecholamines) were obtained in 11 such patients. The studies were made at the time patients became unresponsive to other vasodilators (hydralazine or prazosin); the vasodilator drug was then discontinued and five days later, the 'no-vasodilator' studies were obtained. Captopril therapy was then started. Optimum daily maintenance dose of captopril varied from 75 to 200 mg in different patients. Studies were again repeated after a period of time equal to the duration of the previous vasodilator therapy. Digitalis and diuretic doses were kept constant throughout. Captopril improved effort tolerance in ten patients. Haemodynamically, mean blood pressure and peripheral resistance were lower than during vasodilator therapy (85 +/- 3.1 v. 92 +/- 3.3 mmHg and 47 +/- 4.4 v. 59 +/- 4.4 U.M2, respectively; p less than 0.05 for both). Cardiac index was higher during captopril treatment (1.95 +/- 0.15 v. 1.63 +/- 0.10 l/m2, p less than 0.01) and pulmonary mean transit was normalized by captopril (14.6 +/- 1.7 v. 18.4 +/- 1.3 s, p less than 0.05). Humoral indices revealed a significant (p less than 0.05) reduction in plasma aldosterone during captopril therapy (25.9 +/- 5.6 ng/dl during captopril, v. 62 +/- 22 ng/dl with no vasodilators and 50.9 +/- 6.1 ng/dl with other vasodilators). Moreover, there was a decrease in circulating plasma catecholamines during captopril treatment, but differences between the three treatment periods were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1983

Experimental evaluation of a posterior drainage system.

We have evaluated an experimental artificial shunt to drain intraocular fluid into the retrobulbar space. The device consists of a hollow needle for insertion into the eye, a slit valve to regulate the drainage pressure, and a dome-shaped outflow system. The device was inserted through the sclera, choroid, and retina into the eyes of cynomolgus monkeys. The system was tolerated without producing retinal detachment. A localized foreign body reaction occurred in the retina, choroid, and sclera adjacent to the device. The intraocular pressure was lowered until fibrous encapsulation of the outflow system occurred.

Animals↗
PubMed1982

Ultraviolet light absorbing pseudophakos.

We evaluated a new compound of polymethylmethacrylate (PMMA) that effectively blocks radiation below 380 nm, while maintaining nearly ideal transmittance characteristics above this wavelength. Our in vitro studies demonstrated no toxicity from this compound. Comparisons in primate eyes showed the standard and ultraviolet (UV)-absorbing plastic to be equally well tolerated.

Animals↗
PubMed1982

Bioavailability of d-pseudoephedrine and azatadine from a repeat action tablet formulation.

The objective of this study was to compare in man the bioavailability of d-pseudoephedrine and azatadine from a repeat action tablet formulation and from conventional tablets. The repeat action tablet, containing 1 mg of azatadine maleate in the coat, and 60 mg of d-pseudoephedrine sulfate in both the coat and the core, was given at 0 hour. A conventional tablet of 60 mg of d-pseudoephedrine sulfate was given at 0 and 4 hours and a conventional tablet of 1 mg of azatadine maleate was given at 0 hour. The plasma levels of d-pseudoephedrine were measured by gas-liquid chromatography and the amount of azatadine in the urine was determined by a mass fragmentographic procedure. The results showed that there were no statistically significant differences in the measured bioavailability parameters (area under plasma concentrations-time curve, maximum plasma concentration and time to reach maximum plasma concentration) for pseudoephedrine from repeat action tablets and conventional d-pseudoephedrine sulfate tablets; neither was there any statistically significant difference in the cumulative urinary excretion of azatadine from the repeat action tablets and conventional azatadine maleate tablets (p less than 0.10). These data clearly demonstrate the bioequivalence of the repeat action tablets and the conventional tablets of d-pseudoephedrine and azatadine.

Adolescent↗
PubMed1982

Comparative bioavailability of d-pseudoephedrine from a conventional d-pseudoephedrine sulfate tablet and from a repeat action tablet.

The bioavailability of a single dose of d-pseudoephedrine sulfate administered to male volunteers in repeat action tablet form (60 mg d-pseudoephedrine sulfate in the coat and 60 mg d-pseudoephedrine sulfate in the core) was compared with the bioavailability of an equivalent quantity of the drug given as two 60 mg conventional tablets, one given at 0 hour and the second 6 hours later. There was no significant difference (P less than 0.10) between the conventional tablets and the repeat action tablet formulation in area under the plasma concentration-time curve and the maximum plasma concentration of d-pseudoephedrine. Based on the data, we conclude that the repeat action tablet formulation and the conventional tablet are bioequivalent.

Adolescent↗
PubMed1982

Comparative bioavailability of a microsize and ultramicrosize griseofulvin formulation in man.

The bioavailability of 500 mg of a microsize formulation of griseofulvin has been compared to two new ultramicrosize griseofulvin formulations, two 165 mg tablets and a 330 mg tablet, in sixteen healthy, male, volunteers in a randomized crossover study design. Based on the griseofulvin plasma levels measured at specified times over a 48-hour period, the major bioavailability parameters (i.e., area under plasma concentration-time curve, maximum plasma concentration, and time to reach maximum plasma concentration) were determined and statistically evaluated. The results showed that one 330 mg ultramicrosize tablet is bioequivalent to two 165 mg ultramicrosize griseofulvin tablets and that either ultramicrosize griseofulvin dosage regimen is bioequivalent to 500 mg of the microsize griseofulvin formulation.

Biological Availability↗
PubMed1979

The spatial relationships and structure of the binuclear iron-sulfur clusters in succinate dehydrogenase.

Two binuclear iron-sulfur clusters (designated S-1 and S-2) are present in succinate dehydrogenase in approximately equal concentration to that of flavin. The large difference in their midpoint potentials (0 and -400 mV, respectively, in the soluble enzyme) permits the acquisition of individual electron paramagnetic resonance spectra characterized by nearly identical rhombic g tensors (gz = 2.025, gy = 1.93, gx = 1.905). Spin-coupling between the two centers is manifested by broadening and splitting of spectra of reconstitutively active and inactive succinate dehydrogenase, respectively, as the temperature is lowered; relief of power saturation of Center S-1 spectra on reduction of Center S 2; and observation of half-field ("delta ms = 2") signals in the dithionite-reduced enzyme. Saturation behavior of fully reduced dehydrogenase is consistent with the presence of S-1 and S-2 at equivalent concentrations/molecule. Simulation of the spin-coupled spectra, assuming dipolar interaction, provides information on molecular structure. Electron paramagnetic resonance spectra of the enzyme in 80% dimethylsulfoxide are nearly identical to the characteristic binuclear spectra obtained with adrenodoxin. These data provide additional evidence for binuclear structure of both Center S-1 and S-2. The extremely fast relaxation of Center S-2 at low temperatures would imply either an anomalously small value of J or an alternative relaxation mechanism, possibly due to the coupling between S-1 and S-2.

Animals↗
PubMed1976

Thermodynamic and EPR characteristics of a HiPIP-type iron-sulfur center in the succinate dehydrogenase of the respiratory chain.

In addition to the two species of ferredoxin-type iron-sulfur centers (Centers S-1 and S-2), a third iron-sulfur center (Center S-3), which is paramagnetic in the oxidezed state analogous to the bacterial high potential iron-sulfur protein, has bwen detected in the reconstitutively active soluble succinate dehydrogenase preparation. Midpoint potential (at pH 7.4) of Center S-3 determined in a particulate succinate-cytochrome c reductase is +60 +/- 15 mV. In soluble form, Center S-3 becomes extremely labile towards oxygen or ferricyanide plus phenazine methosulfate similar to reconstitutive activity of the dehydrogenase. Thus, even freshly prepared reconstitutively active enzyme preparations show EPR spectra of Center S-3 which correspond approximately to 0.5 eq per flavin; in particulate preparations this component was found in a 1:1 ratio to flavin. All reconstitutively inactive dehydrogenase preparations that Center S-3 is an innate constituent of succinate dehydrogenase and plays an important role in mediating electrons from the flavoprotein subunit to most probably ubiquinone and then to the cytochrome chain.

Animals↗
PubMedDate not supplied

'Someone who cares:' a qualitative investigation of cancer patients' experiences of psychotherapy.

Although psychotherapy for cancer patients is known to be effective, there is little in the research to indicate what elements of their therapy patients find most helpful. To explore this question, we interviewed cancer patients diagnosed with metastatic disease who had been offered two different forms of individual psychotherapy as part of a larger funded study. These interviews were then transcribed and analysed using grounded theory. Our aim was to explore patients' psychotherapy experience from their perspective and to determine what common elements in the two approaches they felt were of greatest benefit. Results indicated that patients offered cognitive behavioural therapy had similar experiences to those who received a type of relaxation therapy that included time for non-specific, patient-centred 'chat'. Central to participants' experiences was the opportunity both therapies gave them to enter a relationship in which they could safely share their thoughts and feelings with someone who seemed genuinely interested in understanding their cancer experience and 'truly cared'. These findings suggest that the unique perspectives of cancer patients can add considerably to our understanding of individual psychotherapy in cancer care settings and how this might be improved.

Adult↗
PubMedDate not supplied

Acute myeloid leukemia in elderly adults.

One hundred and fifteen previously untreated adults aged over 60 years were referred to St Bartholomew's Hospital between 1978 and 1986 for management of acute myeloid leukemia (AML). Twenty-seven patients received symptomatic or palliative treatment only because combination chemotherapy was considered inappropriate. Eighty-eight patients received intensive chemotherapy with curative intent. There was a 48 per cent 'early death' rate and a 24 per cent incidence of resistant disease; complete remission (CR) was achieved in 25/88 patients (28 per cent). By multivariate analysis, a blast count less than 50 x 10(9)/l at presentation was the only factor predictive for achievement of CR whilst the latter and a presentation blast count less than 50 x 10(9)/l predicted for superior survival. Treatment was often curtailed on account of unacceptable toxicity; only 2/88 patients received the planned six cycles of treatment. Two patients died in CR. Four patients are alive in first CR at 3-9 years from treatment; one is alive in second CR following meningeal relapse. Overall survival was significantly worse than that of a contemporaneous group of adults aged 15-59 years treated at this hospital, but duration of CR was comparable. There are great difficulties involved in the intensive treatment of AML in elderly adults, but the major survival benefit gained by achieving CR should stimulate the search for better tolerated but still curative regimens.

Aged↗
PubMedDate not supplied

Comparison of intranasal triamcinolone acetonide with oral loratadine for the treatment of patients with seasonal allergic rhinitis.

This multicenter, double-blind, randomized, controlled, parallel-group study compared the safety and efficacy of intranasal triamcinolone acetonide with oral loratadine in relieving symptoms of ragweed-induced seasonal allergic rhinitis. Patients from community-based allergy practices with a history of at least two seasons of seasonal allergic rhinitis verified by a positive skin test received either once-daily treatment with intranasal triacinolone acetonide 220 micrograms plus 1 placebo capsule or oral loratadine 10 mg plus placebo nasal spray. Other medications for rhinitis were prohibited. Changes in rhinitis symptoms were assessed by using patient evaluations, physician global evaluations, and withdrawal rates. Efficacy was evaluated in 274 of 298 patients randomized to treatment (134 to triamcinolone acetonide and 140 to loratadine). Mean total nasal symptom scores for weeks 1, 2, 3, and 4 and the overall score showed greater improvement (P = 0.001) with triamcinolone acetonide than with loratadine. Improvement in all rhinitis symptoms was significantly greater with triamcinolone acetonide than with loratadine; there was a trend for greater improvement in ocular symptoms with triamcinolone acetonide. Physicians' global evaluations indicated triamcinolone acetonide provided moderate-to-complete relief in 78% of patients compared with 58% of loratadine-treated patients (P < or = 0.0001). Both treatments were well tolerated; headache was the most commonly reported adverse event in both groups. Intranasal triamcinolone acetonide was significantly more effective than oral loratadine in relieving the symptoms of seasonal allergic rhinitis.

Administration, Intranasal↗