Biomedical subjects
Publications and source records attributed to Y Tan.
The test was conducted on the interrelated factors of germination of Nutmeg seeds. The result indicated that germination occurred fast and exuberantly (up to 88.8%) when the fresh and plump seeds (collected in summer or early autumn) were shown and expedited in clean sand in the complete shade during May-August after being treated with wet sand for 96 hours.
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The absorption and diuretic effect of furosemide 40 mg alone (F), and of the free (F + T) and the fixed (FT) combinations of furosemide 40 mg and triamterene 50 mg have been compared in 12 healthy young men. A slight reduction in the area under the concentration-time curve (AUC) of plasma furosemide was found for the fixed combination (AUC480) F2.58 micrograms.h.ml-1; F + T 2.46 micrograms.h.ml-1; FT 1.97 micrograms.h.ml-1. There was a significant reduction in the AUC480 of plasma triamterene (F + T 204.9 micrograms.h.l-1; FT 130.2 micrograms.h.l-1). Sodium excretion after F + T and FT was more pronounced than after F (F + T 302 mmol; FT 311 mmol; F259 mmol). When compared to F alone, there was a reduction in the 24-hour potassium excretion after F + T as well as after FT (F 121 mmol; F + T 104 mmol; FT 107 mmol). It is concluded that the absorption of triamterene was significantly reduced after ingestion of the fixed combination tablet. However, in healthy male adults this had no influence on its natriuretic and potassium-sparing effect as compared to the free combination.
In a randomized, double-blind, between-patient, multicenter study in 301 patients with ROAD, the efficacy and tolerability of the new long-acting selective beta 2-sympathicomimetic drug formoterol (12 micrograms inhalation b.i.d.) was compared with salbutamol (200 micrograms inhalation q.i.d.). There was no statistically significant (s.s.) difference in acute reversibility and long-term efficacy of both drugs, measured by the point in time of expected maximal effect. However, formoterol had a highly s.s. longer duration of action than salbutamol, as shown by peak expiratory flow (PEF) measurements: the overall mean morning PEF in the formoterol group was 341 L/min. 14 h after the last taken dose and in the salbutamol group this measure was 304 L/min 9 h after the last dose. The patients taking formoterol had s.s. less asthma attacks and needed s.s. less rescue medication than those taking salbutamol. In the global assessment of efficacy, formoterol was accepted as being s.s. better ("very good" + "good": 76%) than salbutamol ("very good" + "good": 50%). The tolerability of each drug, as reflected by adverse reactions and global assessment, was equally good in both groups. Ninety-one percent of the patients in the formoterol group wanted to receive the same drug again versus 79% in the salbutamol group.
The effects of iv salbutamol on respiratory mechanics were studied in six infants with bronchopulmonary dysplasia. Salbutamol was infused at a dose of 30 micrograms/kg over 30 min in five infants; a sixth infant received 66.7 micrograms/kg over 4 min. Salbutamol caused improvement in total respiratory system compliance and in airflow resistance. There was no correlation between salbutamol serum concentration and pulmonary function. Elimination half-time appears to be dictated in these infants more by the distribution volume (Vd) than by clearance (Cl). The area under concentration-time curve of salbutamol correlated inversely to the change in heart rate (HR). There was a significant positive correlation between Vd and percent HR change. These data provide evidence that preterm infants have measurable activity of bronchiolar beta 2 receptor responsive to salbutamol.
The LAK cells activity of the peripheral blood from 28 patients of the gastric cancer was reported. The results showed that the LAK cells activity was significantly lower in the patients than normal controls (P less than 0.001), and there was positive correlation between the LAK cells activity and IL-2 activity (P less than 0.01). In certain extent the LAK cells in the patient increased IL-2 concentration during incubation, but it did not reach the normal level. The plasma of the patient was inhibitory to LAK cells activity of normal human. The LAK cells activity obviously revived after the tumor resected.
Seventy three cases of gastrointestinal smooth muscle tumors (GISMT) were collected and their correlation between pathology and prognosis and their histogenesis was studied, microscopically, the following parameters were evaluated: 1. cellularity; 2. grade of differentiation; 3. nuclear pleomorphism; 4. mitotic rate/10 HPF. All cases were followed up, but from only 47 information was elicited. To study the histogenesis, the technique of immunohistochemical staining to desmin, S-100 protein was used in all the cases and five were examined by EM. The results showed that the mitotic rate was the most important and reliable pathological parameter used to differentiate between benign and malignant tumors, and to evaluate the prognosis of a given tumor; in the cases which showed active mitosis, tumor size was important to evaluate the prognosis; the other histologic parameters of less, if any, significance in evaluation of prognosis. The authors supported the hypothesis that GISMT might mainly be derived from primary mesenchymal cells potentiated with smooth muscle cells differentiation. The hypothesis that GISMT are derived from nerve tissue waits for further evidence.
A single intravenous injection of adriamycin (5 mg/kg) into rats caused the full expression of nephrotic syndrome characterized by heavy proteinuria, hypoalbuminemia, hypercholesterolemia, thoracic and ascitic fluid; swelling and fusion of foot processes of epithelial cells could be observed under electron microscope; histologic examination by light microscopy did not reveal any significant changes. The features of the model in clinic and pathology were very similar to those described humans with minimal change nephrotic syndrome. The observation in the various periods of the model indicated that the ultrastructure changes in epithelial cells occurred prior to the onset of proteinuria. The present study, combined with the results of quantitative analysis with image analyzer for alteration of glomerular polyanions, suggests that both morphologic changes and proteinuria may be the consequence of a common primary event that is the loss of glomerular polyanions. The model has the advantages of being rather simple and convenient; providing lasting proteinuria and pathological changes in stable condition; and having high reproducibility and a sufficient supply of the drug used.
Clinical analysis of serum lipoprotein (Han and minorities) in 117 patients of different nationalities with acute cerebrovascular disease (91 with cerebral infarction, 26 with cerebral hemorrhage) and 1000 normal people (control group). These results showed that these was no statistically significant difference between patients of Han and minorities, the level of serum HDL-C in patients with acute CVD was much lower than in control group, level of serum TG in patients was greatly higher than that in control group.
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The kinetics of naproxen was studied in healthy volunteers after cutaneous application of gels containing 5 and 10% of the drug. Bioavailability was estimated from serum concentration and cumulative urinary metabolite excretion data, both determined up to 96 hours after drug administration. The mean bioavailability after the 10% gel was 1.1% (serum data) and 1.0% (urine data), and after the 5% gel it was 2.1% (serum data) and 1.8% (urine data). Despite the small amount of naproxen absorbed, a potential pharmacological effect, due to cutaneous accumulation of the drug following topical administration, may be suggested from the course of the serum concentration-time curves.
Bacillus thuringiensis strain AF101 possesses a single plasmid (pAF101) with a molecular size of 42 MDa (69 kb). During plasmid curing experiments in strain AF101, we found that a phage (J7W-1) was induced by ethidium bromide treatment. Moreover, the phage genome (48 kb) hybridized only with pAF101 on a Southern blot of the DNA of a cleared lysate prepared from strain AF101. Comparison of the restriction patterns of pAF101 and J7W-1 phage DNA revealed that pAF101 contains not only the entire phage DNA but also a plasmid-specific DNA region. These results indicate that the J7W-1 genome has been stably integrated into pAF101 in strain AF101. Integration of the J7W-1 genome into a plasmid was also observed after phage infection of the type strain of B. thuringiensis subsp. israelensis.
The effects of rheumatoid arthritis disease activity on the pharmacokinetics of the highly albumin-bound nonsteroidal anti-inflammatory drug naproxen were studied in six patients during chronic therapy. In the same patients, kinetics during active disease were compared with those in improvement. Active disease is commonly associated with hypoalbuminemia: 30 +/- 4 gm/L vs. 41 +/- 2 gm/L (mean +/- SD) at the time of improvement. Total naproxen concentrations were significantly lower in active disease, together with a larger apparent volume of distribution (10.6 +/- 1.8 L vs. 8.4 +/- 1.3 L; P less than 0.05) and total body clearance (0.79 +/- 1.8 L/hr vs. 0.59 +/- 0.14 L/hr; P less than 0.001). Peak unbound naproxen concentrations were 29% +/- 19% (P less than 0.05) lower at the time of improvement. The unbound clearance was found diminished during active disease (390 +/- 277 L/hr) in comparison with improvement (488 +/- 343 L/hr; P less than 0.05). Clinical implications of the alterations in naproxen kinetics induced by polyarticular inflammation in patients with rheumatoid arthritis are discussed.
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After multiple oral doses of 500 mg naproxen twice daily, eight young healthy male volunteers and six male and female elderly patients participated in a pharmacokinetic study. Serum naproxen levels were measured by high-pressure liquid chromatography; protein-unbound drug was determined after equilibrium dialysis. A significantly lower maximal serum concentration (Cpeak), smaller area under the curve during one dose interval [AUC(0-12)], larger total body clearance (CL/F) and apparent volume of distribution (V/F body wt-1) were found for the total drug in elderly patients. The pharmacokinetics of the protein-unbound drug showed higher trough and peak concentrations, larger AUC(0-12)u, and smaller (CL/F)u and (V/F)u in the elderly patients. The unbound fraction (less than 1% of total naproxen) showed concentration dependency; in the elderly, a larger unbound fraction was found. Pharmacokinetic differences between the elderly and the young may be explained by a lower serum albumin concentration in the aged, together with a decrement in binding affinity of naproxen to albumin; moreover, the clearance of unbound drug was significantly reduced in the elderly (281 +/- 96 l/h) as compared with the young (713 +/- 164 l/h). We conclude that age-related factors increase serum unbound naproxen concentrations. It is, therefore, advisable to start treatment with naproxen in the elderly at a low dosage.
Patients with rheumatoid arthritis often have hypoalbuminaemia as a sign of disease activity. In view of the extensive binding of naproxen to albumin, the pharmacokinetics of total and unbound drug were studied in eight patients and eight healthy male volunteers during chronic intake of 500 mg twice daily. The area under the serum concentration-time curve of total naproxen during a dose interval, AUC (0,12), smaller in patients (641 +/- 101 mg l-1 h) than in volunteers (896 +/- 85 mg l-1 h; P less than 0.0001). The unbound naproxen AUCu (0,12) was larger in patients (1.9 +/- 0.9 mg l-1 h) than in volunteers (0.7 +/- 0.2 mg l-1 h; P less than 0.01). The higher unbound naproxen concentrations in patients were accompanied by an approximately 40% increase in apparent clearance/bioavailability (CL/F) and a 60% increase in volume of distribution (V/F). Both CL/F and V/F were inversely correlated with the individual serum albumin concentration (r = 0.76, P less than 0.001; r = -0.85, P less than 0.001, respectively). The high unbound naproxen concentration in the serum of patients with active rheumatoid arthritis and concomitant hypoalbuminaemia is not known to be accompanied by an increase in side effects and may be beneficial if anti-inflammatory effects correlate with unbound drug concentration.
A problem usually not taken into account when a quantitative HPLC method for phenylbutazone is developed is the degradation of this drug and its metabolites not only upon storage, but also on extraction under acidic conditions, especially when the temperature is raised. Moreover, the degradation products in the chromatograms may interfere with the determination of gammahydroxyphenylbutazone. In our newly developed HPLC method, using feprazone as an internal standard, extreme care is taken to avoid degradation of the compounds during the extraction procedure. In view of the present results it is concluded that previously published data on phenylbutazone, oxyphenbutazone and gammahydroxyphenylbutazone levels should be considered with reserve.