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Biomedical subjects

H Dhaliwal

Publications and source records attributed to H Dhaliwal.

8 recordsLinked to original sources

Evidence for two components of object-based selection.

A wealth of research has shown that observers can bias visual processing toward specific locations, but the role of object-based selection is less clear In support of object-based selection, previous research has shown that when two objects are presented simultaneously, observers are better at reporting two attributes from one of the objects than one attribute from each object. However there has been controversy over whether this effect is best explained by object-based selection or spatial selection. Our work suggests that there are two separate components of selection in this task: (Ca) a spatial component that is observed when the relevant targets are cued for observers before the onset of the stimulus display and (b) an object-based component that can still be observed when the first component has been eliminated. The latter effect replicates the initial evidence in favor of object-based selection, and can be demonstrated even when the relevant targets are cued after the offset of the target stimuli.

Attention↗

Use of dexamethasone and granisetron in the control of delayed emesis for patients who receive highly emetogenic chemotherapy. National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: To evaluate the roles of granisetron and dexamethasone for emesis control on days 2 through 7 after the administration of cisplatin in doses of 50 mg/m2 or greater to patients who had not previously received chemotherapy. PATIENTS AND METHODS: Four hundred thirty-five eligible and assessable patients were randomized to one of two arms in a double-blind fashion: arm A; granisetron 3 mg intravenous (i.v.) plus dexamethasone 10 mg i.v. prechemotherapy followed by granisetron 1 mg orally at 6 and 12 hours, then granisetron 1 mg orally and dexamethasone 8 mg orally twice daily on days 2 through 7 (219 patients); arm B; as in arm A but with placebo substituted for granisetron on days 2 through 7 (216 patients). All patients completed diaries in which episodes of emesis and severity of nausea were recorded. RESULTS: The addition of granisetron on days 2 through 7 had no discernable impact on nausea and vomiting during this period. CONCLUSION: The administration of a 5-hydroxytryptamine3, receptor (5-HT3) antagonist, in this case granisetron, after 24 hours conferred no benefit. This negative result needs to be assessed in light of conflicting literature, but at present it does not appear that the routine use of these drugs in this setting is justified.

Antiemetics↗

Comparative clinical efficacy and safety of immediate release and controlled release hydromorphone for chronic severe cancer pain.

BACKGROUND: The short elimination half-life of hydromorphone necessitates 4-hourly dosing to maintain optimal levels of analgesia in patients with chronic cancer pain. The purpose of this study was to compare the clinical efficacy and safety of controlled release hydromorphone administered every 12 hours and immediate release hydromorphone administered every 4 hours in patients with chronic severe cancer pain. METHODS: Forty-eight patients with stable chronic severe cancer pain were randomized, in a double-masked crossover study, to controlled release hydromorphone every 12 hours or immediate release hydromorphone every 4 hours for 7 days each. Pain intensity was assessed using a visual analog scale (VAS) and the Present Pain Intensity Index of the McGill Pain Questionnaire. Nausea and sedation were also assessed using a VAS. Assessments were made by the patient four times a day at 7:00 a.m., 11:00 a.m., 3:00 p.m., and 7:00 p.m. Use of rescue hydromorphone also was recorded by the patient. RESULTS: Forty-five patients completed the study (26 women, 19 men; mean age, 57.1 +/- 13.6 years) and received a mean daily dose of 76 +/- 133 mg (range, 6-768 mg). There were no significant differences between controlled release hydromorphone and immediate release hydromorphone in overall VAS pain intensity scores (19 +/- 14 vs. 20 +/- 14 mm), ordinal pain intensity scores (1.2 +/- 0.8 vs. 1.2 +/- 0.8) and pain scores by day of treatment or time of day. The daily rescue analgesic consumption during controlled release hydromorphone and immediate release hydromorphone did not differ significantly overall (1.1 +/- 1.1 vs. 1.0 +/- 1.1 doses per day) or with respect to time of day. There were no significant differences in overall VAS sedation scores (18 +/- 18 mm vs. 19 +/- 18 mm) and in overall mean VAS nausea scores (12 +/- 15 mm vs. 11 +/- 14 mm) between controlled release hydromorphone and immediate release hydromorphone. CONCLUSIONS: Controlled release hydromorphone administered every 12 hours is as effective as immediate release hydromorphone administered every 4 hours in the management of patients with chronic severe cancer pain. The benefits of controlled release hydromorphone lie in the convenience of its capsule formulation, which can be sprinkled on soft food, and its 12-hour duration of action, which allows patients uninterrupted sleep and improved compliance.

Chronic Disease↗

Combination chemotherapy with teniposide (VM26) and carboplatin in small cell lung cancer.

Seventy patients with previously untreated histologically proven small cell lung cancer (SCLC) were treated with a combination of teniposide 60 mg/m2 intravenously (i.v.) on days 1 through 5 and carboplatin 400 mg/m2 i.v. on day 1 every 28 days for six courses. Patients with limited stage disease, (LD) who achieved a response, subsequently received 2,000 cGy prophylactic cranial and 3,000 cGy involved field thoracic radiotherapy. Of the 70 patients, 62 were evaluable for response: 47 patients (76%) achieved an objective response; 14 of 29 patients (48%) with LD had a complete response (CR), with a partial response (PR) plus CR rate of 76%. Seven of 33 patients (21%) with extensive disease (ED) achieved a CR, with a combined PR and CR rate of 76%. Median time to progression (TTP) for all responders was 292 days (42 weeks). Median duration of survival for all LD patients was 415 days (59 weeks). Survival for LD patients was 88% at 6 months, 61% at 12 months, and 29% at 18 months. Median survival duration for all patients in the study was 311 days (44 weeks), with a survival of 79% at 6 months, 44% at 1 year, and 16% at 18 months. Myelosuppression was the main toxicity, with World Health Organization (WHO) grade 3 or 4 infection occurring in 33% of patients. Two patients died of pneumonia, one complicated by renal failure, and another suffered cardiac arrest related to treatment. The high activity of this drug combination justifies its use as a first-line treatment of previously untreated SCLC.

Adult↗

Teniposide (VM-26) and carboplatin as initial therapy for small cell lung cancer.

Forty-four patients with previously untreated histologically proven small cell lung cancer (SCLC) were treated with a combination of teniposide 60 mg/m2 intravenously (IV) on days 1 through 5 and carboplatin 400 mg/m2 IV on day 1 every 28 days for six courses. Patients with limited disease (LD) subsequently received prophylactic cranial and thoracic radiotherapy. Of the 44 patients, 40 were evaluable for response: 31 (78%) achieved an objective response; 9 of 18 patients (50%) with LD had a complete response (CR), with a partial response (PR) plus CR rate of 78%. Two of 22 patients (9%) with extensive disease achieved a CR, with a combined PR and CR rate of 77%. Median duration of response for all evaluable patients was 253 days (36 weeks). Median duration of survival for LD patients was 368 days (52 weeks). Survival of LD patients was 86% at 6 months, 52% at 12 months, and 26% at 18 months. Median duration of survival for all patients in the study was 275 days, with a survival of 79% at 6 months, 36% at 1 year, and 12% at 18 months. Myelosuppression was the main toxicity, with World Health Organization (WHO) grade 3 or 4 infection occurring in 38% of patients. However, no patient died of sepsis or hemorrhage. Treatment was otherwise well tolerated, with no neurotoxicity or nephrotoxicity documented. The high activity of this drug combination justifies its use as first-line treatment of previously untreated SCLC.

Adult↗

Correlation between antioxidant changes during hypoxia and recovery on reoxygenation.

Changes in myocardial antioxidants due to different durations of hypoxia at normal or lower temperatures were correlated with the recovery of structure and function on reoxygenation. Hearts perfused with substrate-free hypoxic buffer at 37 degrees C for 5 or 10 min and at 22 degrees C for 10 min showed a significant depression in the contractile function and rise in resting tension. Reoxygenation of these hearts at 37 degrees C for 20 min resulted in a recovery of these functions. On reoxygenation, hearts made hypoxic for 10 min at 37 degrees C showed poor recovery of the contractile function, increase in malondialdehyde content and a dramatic increase in the creatine phosphokinase activity in the coronary effluent. Addition of catalase to the perfusion medium markedly improved function recovery of these hearts. Hypoxia at 37 degrees C for 5 min or at 22 degrees C for 10 min with or without reoxygenation had no effect on superoxide dismutase (SOD) or glutathione peroxidase (GSHPx) activities. These antioxidants were depressed in hearts made hypoxic for 10 min at 37 degrees C with no further change on reoxygenation. Neither SOD nor GSHPx was detected in the coronary effluent during hypoxia or reoxygenation. Hypoxia at 37 or 22 degrees C for 10 min caused significant ultrastructural changes, and on reoxygenation 37 degrees C hypoxic hearts showed exacerbation, whereas the 22 degrees C hypoxic hearts showed recovery. These data support the hypothesis that reduced antioxidant reserve during hypoxia may contribute to the oxidative injury on reoxygenation, suggesting that maintenance of endogenous antioxidant levels during hypoxia may be important for recovery.

Animals↗

Pure red cell aplasia--evidence for an inhibitory action of the bone marrow adherent cell layer.

Evidence is presented for an inhibitory action of the bone marrow adherent cell layer on erythropoiesis in a case of pure red cell aplasia. Cultures of the patient's bone marrow with autologous and normal plasma showed normal numbers of CFU-C, but total absence of BFU-E. There was no inhibition of BFU-E when normal bone marrow was cultured with the patient's plasma. T-cell depletion of the patient's bone marrow did not affect these results, but after removal of the adherent cells, normal numbers of BFU-E were cultured. These observations suggest that the adherent cells, which are predominantly macrophages, were responsible for the inhibitory action on erythropoiesis.

Aged↗