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Biomedical subjects

K R Patel

Publications and source records attributed to K R Patel.

At least 73 records · Page 4Linked to original sources
PubMed1986

Bronchodilator activity of a new inhaled beta 2-adrenoceptor agonist, tulobuterol and its protective effect in exercise-induced asthma.

In fifteen patients with asthma tulobuterol, a new beta 2-adrenoceptor agonist, given by inhalation in 100 micrograms increments up to a cumulative dose of 600 micrograms produced dose related increases in both the FEV1 and FVC. The bronchodilation was observed within 5 min of the first dose. In a further nine patients tulobuterol 200 micrograms and 400 micrograms aerosol inhibited exercise-induced asthma following 6-8 min treadmill exercise and the effect was comparable to 200 micrograms salbutamol aerosol. Minor muscle tremors were observed in two patients with 400 micrograms of tulobuterol but no significant changes in pulse rate or blood pressure were noted.

Adult↗
PubMed1986

A comparison of oral astemizole with topical sodium cromoglycate in the treatment of hay fever.

An open, parallel group study was carried out in 95 hay fever patients during the 1984 season to compare the efficacy of oral astemizole with that of topical sodium cromoglycate. Patients were allocated at random to receive astemizole once daily (30 mg during the first week, then 10 mg for the rest of the study period) or sodium cromoglycate (2%), administered 6-times daily intranasally and 4-times daily in the eyes, for a maximum of 8 weeks. The severity of patients' nasal and ocular symptoms was assessed daily on two separate 100 mm visual analogue scales throughout the study period. No statistically significant difference could be detected between the two treatment groups in the control of either nasal or ocular symptoms. Side-effects in both groups were minor and transient. It is suggested that astemizole, however, has the advantage of greater patient convenience and cost effectiveness in hay fever sufferers.

Administration, Oral↗
PubMed1986

The rate of appearance of thyroid hormone nuclear receptor is increased during deoxyribose nucleic acid synthesis in GC cells: analysis of thymidine-treated GC cells using dense amino acid labeling.

The growth rate of GH-producing rat pituitary tumor cells (GC cells) is dependent on thyroid hormone. Previous studies have shown that GC cells can be partially synchronized in the DNA synthesis phase (S-phase) of the cell cycle by a 25-h incubation with 2 mM thymidine. Measurements in GC cells partially synchronized in S-phase showed a significant increase in cellular thyroid hormone nuclear receptor appearance and disappearance in thymidine-treated GC cells using dense amino acid labeling and subsequent sucrose gradient ultracentrifugation. In comparison with GC cells in asynchronous culture, thymidine treatment causes a steady state increase in thyroid hormone nuclear receptors which results from an increase in the receptor appearance rate without an effect on the disappearance rate. Thus, position in the cell cycle appears to be another factor that influences the appearance rate of nuclear thyroid hormone receptors.

Animals↗
PubMed1986

Dose-duration effect of sodium cromoglycate aerosol in exercise-induced asthma.

The dose-duration effect of sodium cromoglycate given by metered dose aerosol was studied in nine patients with exercise-induced asthma. Exercise tests were carried out at 15, 135 and 255 min after placebo, sodium cromoglycate 2 mg, 10 mg and 20 mg. The protective effect and the duration of action were dose-related. The new metered dose aerosol delivering 5 mg of sodium cromoglycate per actuation allows greater flexibility in adjusting the dosage and frequency of administration for individual patients.

Administration, Inhalation↗
PubMed1985

Modification of vesicle surfaces with amphiphilic sterols. Effect on permeability and in vivo tissue distribution.

In this paper, we describe the permeability of vesicles prepared with various synthetic cholesterol derivatives. Cholesterol derivatives with side-chains ending in hydroxyl groups reduced the permeability of unilamellar vesicles. However, addition of cholesterol derivatives with terminal amino groups makes the vesicles more permeable. Vesicles prepared with a short-chain amino-cholesterol derivative were found to be less permeable in phosphate-buffered saline, but not in bovine serum, while long-chain amino-cholesterol-containing vesicles were very permeable in both media. Studies in vivo indicate a rapid clearance rate for intravenously administered amino-cholesterol-containing vesicles with a concomitant increase in liver uptake. However, no difference was found in either the clearance or tissue distribution of control vesicles and the less permeable hydroxyl-cholesterol-containing vesicles.

Animals↗
PubMed1985

Pulmonary tuberculosis in residents of lodging houses, night shelters and common hostels in Glasgow: a 5-year prospective survey.

Despite a high prevalence of pulmonary tuberculosis in the vagrant population in large cities, this group is reluctant to accept chest radiograph screening and outpatient chemotherapy. In order to improve the response rate, inducements were given for chest radiographic examinations between 1978 and 1982 to residents in lodging houses, night shelters, common hostels in Glasgow. The response rate improved and 133 cases of active pulmonary tuberculosis were found. Of these, 63% had positive sputum for Mycobacterium tuberculosis. The clinical details were available in 105 cases; 40 residents completed adequate chemotherapy and there were 15 deaths. Six deaths could be attributed directly or indirectly to pulmonary tuberculosis. Procedures for case tracing should be improved if this reservoir of pulmonary tuberculosis is to be reduced.

Adult↗
PubMed1985

Dose-response effect of sodium cromoglycate pressurised aerosol in exercise induced asthma.

The effects of 2, 10, and 20 mg of sodium cromoglycate delivered by aerosol were compared with those of placebo in a double blind study in 11 patients with extrinsic and exercise induced asthma. The effect of nebulised sodium cromoglycate delivered through a Wright nebuliser (estimated dose 12 mg) was also studied. Patients exercised on a treadmill for six to eight minutes at submaximal work loads on five days, 30 minutes after inhaling placebo or sodium cromoglycate. The FEV1 was recorded before treatment, before exercise, and up to 30 minutes after exercise. Mean baseline values of FEV1 before and after placebo or sodium cromoglycate did not differ significantly on the five days. After exercise the mean (SEM) maximal percentage fall in FEV1 after placebo; 12 mg sodium cromoglycate nebuliser solution; and 2, 10, and 20 mg sodium cromoglycate aerosol were 31.1 (3.8); 9.4 (2.1); and 19.4 (4.6), 13.7 (3.5), and 9.4 (1.9). Sodium cromoglycate inhibited exercise induced asthma at all doses used; the protective effect of the aerosol increased from 2 to 20 mg. The protective effect of 20 mg sodium cromoglycate aerosol was similar to that seen with 12 mg nebulised solution. Our results suggest that the effect of sodium cromoglycate aerosol in exercise induced asthma is dose related.

Adult↗
PubMed1985

Tulobuterol in the management of obstructive airways disease in adults.

Beta 2-adrenergic agents are useful in the management of acute and chronic asthma. Chronic bronchitis and emphysema are less responsive to bronchodilator therapy; however, a trial of beta 2-agonists is warranted in search of a reversible component. The newer beta 2-sympathomimetic agents have no important differences in the quality of bronchodilation, but individual patients may respond more favorably to one drug than to another. Most of the common adverse effects (eg, tremor and tachycardia) are an extension of the pharmacologic effects, so there are no important differences at equipotent doses. When chronic symptoms necessitate maintenance treatment, the frequency of dosing may become a deciding factor in the selection of a bronchodilator. Since tulobuterol is recommended for twice-a-day dosing, it may be more convenient for the patient than beta 2-sympathomimetics that require more frequent administration. The prolonged duration of action of tulobuterol minimizes the need for nocturnal drug administration, allowing the patient to sleep through the night. Thus tulobuterol offers the benefits of extended symptomatic protection and improved patient compliance.

Adrenal Cortex Hormones↗
PubMed1985

Biodistribution of phospholipid vesicles in mice bearing Lewis lung carcinoma and granuloma.

Murine biodistributions of vesicle-encapsulated [111In]NTA were obtained under a number of conditions. These included normal animals, those bearing s.c.- or i.v.-implanted Lewis Lung Carcinoma (LLC) and those having both s.c.-LLC and sterile granuloma. Variations in the distributions were observed with a preinjection of unlabeled aminomannose (AM) vesicles or an increase in the labeled vesicle size. It was found that s.c. LLC exhibited uptake of between 10 and 25% injected dose/g (% ID/g) depending upon tumor mass with larger lesions having lower accumulation. Significant uptake enhancement (p less than 0.05) occurred after AM blockade. Similar results hold for the i.v.-injected LLC cells implying targeting to both primary and metastatic sites. By increasing vesicle size by a factor of 4, uptake by s.c. LLC declined to essentially blood levels; e.g., 2% ID/g. Granuloma accumulations were also at circulating values and, unlike s.c. LLC, could not be imaged.

Animals↗
PubMed1985

Comparison of two calcium antagonists, verapamil and gallopamil (D-600), in exercise-induced asthma.

The effect of inhaled verapamil and gallopamil (estimated dose 3 mg) was studied in 10 patients with exercise-induced asthma. Saline was used as a control. Verapamil and gallopamil modified exercise-induced asthma in 8 of the 10 patients and the degree of inhibition with both the drugs was comparable. Gallopamil, which is a more potent vascular smooth muscle calcium antagonist when compared to verapamil, failed to show a greater protective effect in exercise-induced asthma in the patients studied.

Administration, Oral↗
PubMed1985

Inhaled ketotifen in exercise-induced asthma--a negative report.

The effects of 2 concentrations of inhaled ketotifen (0.25 g/l and 0.5 g/l) were compared with saline in 7 extrinsic asthmatics with exercise induced asthma (EIA). Inhaled ketotifen produced bronchodilatation with a significant increase of 15.4% on mean baseline FEV1 at the higher concentration (p less than 0.05). After exercise the mean percentage fall in FEV1 was 38.4% in the saline group, with no significant difference in the ketotifen pretreated groups, although 2 patients did not have EIA after inhalation of either ketotifen concentrations.

Adolescent↗
PubMed1984

Mouse Lewis lung carcinoma and hepatoma ascites treatment by combination of liposome chemotherapy and non-specific immunotherapy.

Liposomes have been used as biological carriers of anti-tumor drugs, and their potential use has been tested in mouse Lewis lung carcinoma and hepatoma ascites tumor models. Ara-C3 given by the intraperitoneal i.p. route either at 35 mg/kg in a single dose or at 2.5 mg/kg/dose with 5 doses/day for 3 days had no effect on the average survival time of i.v. implanted LLC. However, the same single dose of Ara-C encapsulated in positively charged MLV significantly improved the average survival time of LLC-bearing mice. MTX was chosen as a test drug for the treatment of hepatoma ascites. Non-encapsulated MTX given at either 3 or 30 mg/kg by the i.p. route had little effect on the average survival of i.p.-implanted hepatoma ascites. However, MTX encapsulated in SUV at a 3 mg/kg dose by the i.p. route significantly improved the average survival time of tumor-bearing mice. A combination of chemotherapy and non-specific immunotherapy has also been tested with these 2 tumor models. Two non-specific microbial immune stimulators, Bacillus Calmette Guérin (BCG) and Corynebacterium parvum (CP) were tested by both the i.v. and i.p. routes. A combination of BCG therapy with non-encapsulated anti-tumor drugs was not effective for either of the tumor models. A combination of BCG therapy with liposome therapy appeared to improve the average survival time of LLC-bearing mice. In particular, BCG treatment by the i.p. route in combination with liposome therapy resulted in a 20% long-term survival rate among treated mice. However, BCG therapy by either route in combination with SUV encapsulated MTX therapy had no effect on the average survival time of hepatoma ascites-bearing mice. Immunostimulation with CP at a given dose appears to be superior to BCG therapy for both tumor models. In the treatment of LLC, injection of CP by either the i.v. or i.p. route appears to be equally effective in combination with liposome therapy. However, for the treatment of hepatoma ascites, CP was only effective by the i.p. route, in combination with liposome therapy.

Animals↗
PubMed1984

Treatment of intravenously implanted Lewis lung carcinoma with liposome-encapsulated cytosine arabinoside and non-specific immunotherapy.

Liposomes have been used as biological carriers of antitumor drugs, and their potential use has been tested using various mouse tumors. In this study, we describe a potential role of liposome-encapsulated 1-beta-D-arabinofuranosylcytosine (Ara-C) with a mouse solid lung tumor model. Non-encapsulated Ara-C at 25 mg/kg dose by the intraperitoneal (i.p.) route on days 1, 4 and 7 had no improving effect on the average survival time of tumor-bearing mice compared to untreated control mice. However, the same dose of Ara-C encapsulated in multilamellar liposomes (MLV) improved the average survival of tumor-bearing mice by 60 to 80%. Ara-C was encapsulated more efficiently when DSPC or DPPC MLV were prepared at temperatures below their respective transition temperatures. DSPC and DPPC MLV prepared at 25 degrees C and DPPC MLV prepared at 50 degrees C were equally effective for in vivo therapy, while DSPC MLV prepared at 60 degrees C were not as effective. Non-specific immunotherapy using BCG (Bacillus Calmette-Guérin, Mycobacterium tuberculosis) and CP Corynebacterium parvum) was effective, particularly when injected by the intravenous (i.v.) route, in prolonging the average survival of tumor-bearing mice. A combination of either i.v. BCG or i.p. CP with liposome therapy gave no further improvement in the average survival of tumor-bearing mice. However, a combination of either i.p. BCG or i.v. CP with liposome therapy was somewhat more effective than either liposome therapy or immunotherapy alone.

Animals↗
PubMed1984

The pharmacological efficacy of a rigid non-phospholipid liposome drug delivery system.

Hydration of an ethoxylate derivative of cholesterol, triethoxycholesterol, results in the formation of stable, rigid, bilayer-like structures capable of encapsulating polar compounds. Studies on the stability and tissue distribution of these liposomes in mice indicate that they are suitable as a drug delivery system. Intraperitoneal injection of triethoxycholesterol encapsulated methotrexate into mice bearing hepatoma ascites tumor results in a doubling of the survival time, relative to untreated mice and those receiving unencaptulated drug. These studies show that fluid, acyl chains are not required for the formation of pharmacologically useful vesicles and that such formulations need not be limited to phospholipid-containing systems.

Animals↗
PubMed1984

The treatment of intravenously implanted Lewis lung carcinoma with two sustained release forms of 1-beta-D-arabinofuranosylcytosine.

Liposomes have been used in recent years as carriers for drugs and molecules of biological importance. In cancer chemotherapy, however, the advantages of liposome encapsulation of antitumor drugs remain uncertain, with the possible exception of the usefulness of encapsulated 1-beta-D-arabinofuranosyl-cytosine (ara-C), an antitumor drug of a very short half-life. Liposome-encapsulated ara-C has been shown by others to enhance significantly the survival time of mice bearing leukemia, and the enhancement may be attributable to the role of liposomes as a slow release system for ara-C. We now further explore the advantages of two sustained release systems for ara-C, namely the liposome-encapsulated ara-C and 1-beta-D-arabinofuranosylcytosine-5'-diphosphate-L-1,2-dipalmitin (ara-CDP-L-dipalmitin, a prodrug of ara-C). Intravenously implanted Lewis lung carcinoma is used as a solid tumor model. The therapeutic effectiveness of the two slow release forms of ara-C given by either i.v. or i.p. injections is examined. Viable tumor cells (1.0 X 10(5) cells/mouse) were inoculated i.v. and treatment was initiated 24 hr later using three schedules of multiple treatments for liposomal ara-C and single or multiple injections of ara-CDP-L-dipalmitin. Liposomal ara-C given by the i.p. route consistently increased the number of cures (greater than 120 days survival). For example, when nine small doses (10 mg/kg) were given on consecutive days by i.p. injections, 50% of mice given liposomal ara-C were cured, compared with 10% cures in the group given ara-C liposomes by i.v. and no cures in mice receiving free ara-C given according to the same schedules. On the other hand, ara-CDP-L-dipalmitin given at a single dose is more effective than an equal dose divided in five injections. However, no cures have been obtained by treatments with ara-CDP-L-dipalmitin. These results have further demonstrated the advantage of liposomes as carriers for antitumor drugs of short half-life.

Animals↗
PubMed1984

Circadian variation in number and affinity of beta 2-adrenoceptors in lymphocytes of asthmatic patients.

To determine whether circadian variation in adrenoceptor function might underlie the 'morning dip' in peak expiratory flow (PEF) rate and its abolition by salbutamol we measured indices of beta-adrenoceptor function (Bmax. and Kd), the ratio FEV1/FVC, and plasma cortisol at 08.00 and 18.00 hours on and off salbutamol (4 mg given orally every 4 h) in five extrinsic asthmatic patients and five normal volunteers. There was a significant circadian variation in receptor numbers (Bmax.) in both the control and asthmatic groups which was not abolished on treatment with salbutamol. Both groups appeared to compensate for loss of receptor number induced by salbutamol administration by increasing receptor affinity. For comparable combinations of drug/time, there was no significant difference between the control and asthmatic groups. We conclude that the 'morning dip' observed in asthmatic patients cannot simply be explained by changes in cell receptor number or affinity, as our results suggest that both groups have intact beta-adrenoceptor function. Nevertheless, our observations of the normal circadian rhythm has important implications for future studies of beta-adrenoceptors in asthmatic patients.

Albuterol↗