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Biomedical subjects

K R Patel

Publications and source records attributed to K R Patel.

At least 37 records · Page 2Linked to original sources
PubMed1993

Functional foot salvage after extensive plantar excision and amputations proximal to the standard transmetatarsal level.

PURPOSE: It is generally accepted that when necrosis extends proximal to the transmetatarsal level a viable and functional foot can no longer be preserved and a major (above- or below-knee) amputation must be performed. However, with continuing advances in operations for limb salvage we felt the need to reexamine this concept. METHODS: In 1983 we initiated a prospective study to evaluate the role of extended foot amputations. All ambulatory patients with necrosis extending proximal to the transmetatarsal level (but not involving the whole foot) were included in the study. Among the 21 patients studied amputations ranged from open guillotine transmetatarsal amputation to removal of the medial or lateral three fifths of the foot. Five of these patients had adequate pedal circulation by clinical and laboratory criteria. The remaining 16 required vascular reconstruction to improve pedal flow. RESULTS: Eighteen (86%) of 21 patients had complete healing of the foot amputations and were ambulatory at the time of discharge from the hospital. Two patients required early above- or below-knee amputations. Three additional patients sustained limb loss in the follow-up period. The cumulative graft patency rate was 94% at 12 months. The cumulative limb salvage rate at 24 months was 84%. The operative mortality rate was 1 (5%) of 21. CONCLUSION: Our experience in a small number of patients suggests that functional foot salvage is possible even when necrosis or gangrene extends proximal to the transmetatarsal level.

Aged↗
PubMed1993

Effect of cetirizine, a potent H1 antagonist, on platelet activating factor induced bronchoconstriction in asthma.

Effect of cetirizine, a potent and specific H1 receptor antagonist, was examined on platelet activating factor-induced bronchoconstriction in 10 patients (5 male, mean [s.e.m.] aged 37.4 [3.6] years) with mild asthma in a placebo controlled, double-blind cross-over study. Airway responses were assessed by measuring specific airway conductance (SGaw). Patients were challenged with a single dose (12-96 micrograms) of PAF that had previously produced a 35% fall in SGaw. PAF challenges were performed after single dose (15 mg) and 1 week's treatment (15 mg twice daily) of cetirizine. There was no significant difference in pre- and post-treatment baseline values of SGaw on different study days and the percentage changes after cetirizine were 38.7 (7.01) and 45.6 (5.52) compared to 50.2 (2.89) and 43.9 (7.26) with placebo respectively. Similarly mean (s.e.m.) area under curve (AUC-SGaw/time course response) was 391 (143) and 514 (85) with cetirizine compared to 565 (37) and 461 (94) with placebo respectively. The difference was not statistically significant. There was no difference in facial flushing and feeling of warmth between cetirizine and placebo. We conclude that PAF induced bronchoconstriction in humans is not mediated by histamine release and that H1 receptor antagonists do not modify PAF induced bronchoconstriction.

Adult↗
PubMed1993

Effect of oral and inhaled cetirizine in allergen induced bronchoconstriction.

Cetirizine is a potent, selective H1 histamine receptor antagonist. The effect of oral and inhaled cetirizine was assessed on the early bronchoconstrictor response to inhaled allergen in 10 mild atopic asthmatic patients in a double-blind, randomized, placebo controlled trial. All were sensitive to Dermatophagoides pteronyssinus and this was used as the provoking allergen. The geometric mean PD20 FEV1 values obtained at allergen challenge were measured as cumulative breath units (c.b.u.) and following oral cetirizine, inhaled cetirizine and placebo were 124.5, 75.7 and 76.7 c.b.u. respectively. These did not differ significantly. We conclude that neither oral nor inhaled cetirizine significantly attenuates the early response to inhaled allergen in atopic asthmatic subjects. However, the method of repeated allergen challenge is likely to be relatively insensitive.

Administration, Inhalation↗
PubMed1993

Phlegmasia cerulea dolens: the role of non-operative therapy.

Thrombectomy and thrombolysis are often advocated in the treatment of phlegmasia cerulea dolens, but frequently result in incomplete clot removal, recurrence of thrombosis, local and systemic hemorrhagic complications and chronic venous stasis; this state is associated with a rate of major amputation and death of up to 50%. Non-operative therapy includes elevation, hydration and heparinization and excludes all methods aimed at surgical removal or chemical lysis of the thrombus. In 1982 it was decided to use non-operative therapy as the first line of treatment for phlegmasia cerulea dolens. In the last 9 years seven extremities in six patients with this condition have been treated. One patient had advanced gangrene on presentation and one underwent emergency thrombectomy. Five extremities (in five patients) were treated with non-operative therapy. Ischemia was rapidly corrected in all five patients. Edema resolved completely after 3-4 days in four patients. There were no complications attributable to the therapy. Two of six (33%) patients died from terminal disease. Non-operative therapy appears to be effective in preventing limb loss and avoiding the risks of thrombectomy and thrombolysis in critically ill patients.

Adult↗
PubMed1993

Cervical aortic arch associated with tetralogy of Fallot.

Forty-seven cases of cervical aortic arch have been reported in the literature. Eleven of these patients had congenital cardiac defects, including tetralogy of Fallot in three. An additional case of cervical aortic arch and tetralogy of Fallot is presented along with a brief review of the literature pertaining to this rare condition.

Adult↗
PubMed1992

Metastatic breast cancer presenting as an ovarian cyst: diagnosis by fine needle aspiration cytology.

A fifty-year-old woman with a history of breast cancer presented with a clinically benign ovarian cyst. Laparoscopic aspiration of cyst fluid was performed and the cytology was suspicious of epithelial neoplasia. At subsequent hysterectomy and bilateral salpingo-oophorectomy, the specimen showed extensive metastatic breast carcinoma. Although the cytological examination of fluid from ovarian cysts is often unrewarding, this case shows that metastatic carcinoma may occasionally be diagnosed in this fashion.

Biopsy, Needle↗
PubMed1992

Dose duration of nebulized nedocromil sodium in exercise-induced asthma.

The dose-duration effect of nebulized nedocromil sodium was studied in ten patients with exercise-induced asthma (7 males mean (SEM) age 30.1 (3.5) yrs and predicted forced expiratory volume in one second (FEV1) 102%). All of these patients showed > 40% protection of their exercise asthma with 4 mg of nedocromil sodium delivered via metered dose inhaler. Three concentrations of nedocromil sodium (0.5, 2.5 and 10 mg.ml-1) and placebo were administered in double-blind, randomized manner. One ml of each solution was nebulized via a Wright nebulizer. Effects were assessed from the mean maximal percentage fall in FEV1 after 6-8 min treadmill exercise at 15, 135 and 255 min following each treatment and expressed as percentage protection. The mean baseline FEV1 values before and after treatments were comparable on four days of testing. Nedocromil sodium inhibited exercise-induced fall in FEV1 at all concentrations (p < 0.001) and the inhibitory effect was still present at 255 min. No differences were observed between active treatments.

Adult↗
PubMed1991

Effect of cetirizine on histamine- and leukotriene D4-induced bronchoconstriction in patients with atopic asthma.

Cetirizine, a derivative of hydroxyzine, is a new compound with potent antihistaminic property without antiserotonin and anticholinergic activities. The effect of both a single dose (15 mg) and 7 days of treatment (15 mg twice daily) with cetirizine, a potent H1 antagonist on bronchoconstriction induced by histamine and leukotriene D4 (LTD4) has been examined in 10 patients with mild atopic asthma in a placebo-controlled, double-blind, crossover study. Cetirizine, after a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of histamine causing a 20% fall in FEV1 (millimolars) were 1.60 (95% confidence interval, 0.82 to 3.11) and 1.67 (0.77 to 3.65), compared with 118.07 (77.22 to 180.54) (p less than 0.0001) and 53.16 (20.50 to 137.84) after cetirizine administration (p less than 0.0002). The mean inhibition after a single dose was twofold higher than after 1 week of treatment (p less than 0.05). After a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of LTD4 causing a 20% fall in FEV1 (micromolars) were 2.26 (1.74 to 2.94) and 2.37 (1.77 to 3.17), compared with 3.90 (2.60 to 5.86) (p less than 0.05) and 3.21 (2.28 to 4.52) after cetirizine administration. This result suggests that cetirizine is a potent H1 antagonist in the human airways. Diminished activity after 1 week of treatment suggests subsensitivity of H1 receptors developing in human airways. The small protective effect after a single dose against LTD4-induced bronchoconstriction indicates a nonspecific rather than a specific receptor antagonism.

Adult↗
PubMed1991

Subclavian artery to innominate vein fistula after insertion of a hemodialysis catheter.

Insertion of hemodialysis catheters for temporary use is now preferentially performed by percutaneous infraclavicular subclavian vein catheterization. This method involves passage of a stiff dilator and a peel-away sheath over a guide wire, and is usually carried out without fluoroscopy. For the most part this has proved to be a valuable and safe approach. However, a small incidence of major complications occurs, which needs to be emphasized. Sixteen cases of arteriovenous fistulas between the subclavian artery or its branches and the subclavian vein have been reported so far in the literature. To date only one case of subclavian artery to innominate vein fistula has been reported. We report the second case with this complication and suggest possible preventive measures.

Adult↗
PubMed1991

Lack of dose-response effect of terfenadine on resting bronchomotor tone in patients with asthma.

Bronchodilatation data from three, four-period cross-over studies were combined to assess the effect of oral terfenadine 60, 120, 180 mg and placebo on the airways of 26 patients with atopic asthma. Meta-analysis of these data showed that mean changes in FEV1 from pre-dose to 4 hr were 11.4, 14.6 and 11.8% for the three doses of terfenadine, respectively, and -2.9% for placebo. There was a significant treatment effect (P = 0.0001) but no effect of dose. Terfenadine, a non-sedating histamine H1-receptor antagonist, caused bronchodilatation in a single dose. Whether this effect is sustained with long-term treatment requires further investigation.

Adolescent↗
PubMed1991

Effect of cetirizine on exercise induced asthma.

The effect of oral and inhaled cetirizine, a potent and specific H1 receptor antagonist, was studied in patients with exercise induced asthma. Twelve patients (five male; mean age 35.2 years) were given oral placebo or cetirizine 10 mg twice daily for one week, double blind and in randomised order, and exercised on a treadmill for six to eight minutes at a submaximal work load two hours after the final dose. There was no significant change in baseline FEV1 after treatment and cetirizine failed to inhibit exercise induced bronchoconstriction (maximum falls in FEV1 28% and 27% of baseline). In a further eight patients (four male; mean age 40.8 years) the effect of 1 ml cetirizine (5 and 10 mg/ml) given through a Wright nebuliser was compared with that of placebo in a double blind trial. The fall in FEV1 after exercise was reduced after both concentrations of cetirizine by 15.2% of baseline after 5 mg/ml and by 10.2% after 10 mg/ml, compared with 23.7% after placebo. In two patients cetirizine had no effect. In a further study cetirizine (10 mg/ml) given by inhalation displaced the geometric mean PC20 histamine 13.1 fold to the right by comparison with placebo. The reason for the difference between the effects of oral and of inhaled cetirizine on exercise asthma is not clear but may be related to differences in local concentration in the airway.

Administration, Inhalation↗
PubMed1990

Prolonged treatment with oral and inhaled tulobuterol does not induce airways tachyphlaxis.

Beta 2-agonists have been shown to induce beta 2-adrenoceptor downregulation in vivo and in vitro. Whether this has any functional relevance remains unclear. Tulobuterol is a new synthetic beta 2-agonist with potent and prolonged bronchodilator activity when given by oral and inhaled routes. The effect of tulobuterol aerosol (400 micrograms q.i.d.) and tulobuterol tablets (2 mg b.i.d.) was studied in patients with chronic asthma and reversible airways obstruction in two separate trials. Tulobuterol produced significant bronchodilatation after the first and final dose over a 6-h period and the effects were comparable. The bronchodilator activity of tulobuterol given by inhalation and oral routes was not attenuated after 6 months of continuous treatment. There was significant improvement in symptom score and lung function measurements. Side effects, predominantly tremors, were observed at the start of treatment with tablet formulation but the incidence and severity of tremors decreased after 6 months. The changes in BP and pulse rate were not clinically significant. These results confirm the potent bronchodilator activity of tulobuterol and the lack of tachyphylaxis after prolonged treatment.

Administration, Inhalation↗
PubMed1990

Development of a probe for the in vivo measurement of airway humidity during anaesthesia.

Airway drying can arise during long-term respiration of anaesthetic dry gases and this may have implications for the function of the airway wall. Monitoring airway humidity can identify drying trends, although previous attempts have been limited for technical reasons. The design and development of a probe to measure mid-tracheal air humidity is described. The device comprises a commercially available capacitive humidity sensor and a thermocouple. The assembled probe is catheter-like with a diameter of 9.5 mm and a length of 312 mm. Water vapour transfer response times of 1.4s (absorption) and 3.6s (desorption) were evaluated for the probe. A preliminary trial to record airway humidity in ambient air and involving six patients was performed during anaesthesia.

Adult↗
PubMed1990

Sphincters in pulmonary veins. An anatomic study in rats.

To better understand blood flow and edema formation in the lung, anatomic evidence for venous sphincters was sought by a scanning electron microscopic investigation of vascular casts in the rat. In the first study, indentations in the casts of veins and arteries were compared. Casts of the pulmonary veins had narrow (1 to 3 microns) circumferential constrictions about every 30 microns in length (range 20 to 50 microns) and before and after accepting tributaries. Most arteries had no constriction. Infrequently, arterial narrowing occurred over long distances (greater than 30 microns). To determine if these indentations could be altered by a neural stimulus, a second study tried to cast the pulmonary microcirculation after the rats were given a blow to the head, but was unsuccessful. In a third study, the pulmonary vasculature of anesthetized rats was cleared and cast. As the resin began to harden and the animals' circulation ceased, half the animals were given a sharp blow on the head. The casts of the veins in the animals that received the blow had deeper bands than the control animals (p less than 0.001). Pulmonary veins have annular constrictions (sphincters) that are strategically located to influence blood flow. They deepen in response to the neural discharge of a head blow and should be considered in the study of neurogenic pulmonary edema.

Animals↗
PubMed1989

The effect of inhaled ouabain on bronchomotor tone and histamine responsiveness in asthmatic patients.

We have studied the effect of inhaled ouabain on resting bronchomotor tone and histamine responsiveness in eight asthmatic patients in an attempt to clarify the role of Na/K ATPase in airway reactivity. Doses ranged from 50 micrograms to 5000 micrograms and were given in a placebo controlled, double blind manner. Baseline FEV1 was recorded prior to inhalation and at intervals up to 30 min thereafter. At 30 min, a histamine provocation test was performed and results expressed as that concentration producing a 20% fall in FEV1. Maximum fall in FEV1 was not significantly different between placebo or any dose of ouabain, ranging from 4.3%-8.2% (p greater than 0.06) nor was histamine reactivity altered significantly (geometric mean range 0.17 mg-0.29 mg [p greater than 0.2]). Unlike animal studies therefore, we have been unable to demonstrate any effect of Na/K ATPase inhibition on airway reactivity in vivo.

Administration, Inhalation↗