Biomedical subjects
Publications and source records attributed to C Lakshmi.
Two fluorophore-dipicolylamine-Zn2+ conjugates are shown by epifluorescence microscopy to stain the membranes of bacterial cells in preference to mammalian cells.
The appearance of phosphatidylserine on the membrane surface of apoptotic cells (Jurkat, CHO, HeLa) is monitored by using a family of bis(Zn2+-2,2'-dipicolylamine) coordination compounds with appended fluorescein or biotin groups as reporter elements. The phosphatidylserine affinity group is also conjugated directly to a CdSe/CdS quantum dot to produce a probe suitable for prolonged observation without photobleaching. Apoptosis can be detected under a wide variety of conditions, including variations in temperature, incubation time, and binding media. Binding of each probe appears to be restricted to the cell membrane exterior, because no staining of organelles or internal membranes is observed.
Modulatory effects of dopamine (DA) on hematotoxicity and antitumor efficacy of cyclophosphamide (CY) were studied in Swiss mice bearing transplantable Ehrlich ascites carcinoma (EAC). DA was administered i.p. at a dose of 50 mg/kg/day for 5 consecutive days beginning day 3 after tumor transplantation. CY (200 mg/kg i.p.) was injected 24 hour after completion of DA treatment. DA pretreatment reduced the suppressive effects of CY on hemoglobin, RBC, total WBC, neutrophil, platelet, and bone marrow nucleated cell counts. Likewise, DA partially prevented the CY-induced fall in pluripotent (CFU-S12) and lineage-specific stem cells for granulocytes (CFU-C) in bone marrow. Moreover, mice receiving a combination of DA and CY illustrated greater reduction in tumor volume, viable tumor cell count and mitotic index along with upregulation of tumor cell apoptosis than CY-only group. As a result, the former group demonstrated prolonged hosts survival. Thus, DA protected to a great extent the hematopoietic cells of tumor bearing hosts from the suppressive action of CY and concomitantly augmented its antitumor efficacy resulting in improved hosts survival.
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Platelet serotonin (5-HT) concentration was measured by HPLC with electrochemical detection in 46 women suffering from cancer of the uterine cervix and 16 matched controls. About 53% reduction (p < 0.05) was recorded in platelet 5-HT level in cancer patients against a control value of 1.29 +/- 0.16 (mean +/- S.E.) nmol per 10(9) platelets. Depletion of intraplatelet 5-HT was positively correlated with clinical stage of the disease although a modest rise (p > 0.05) in platelet 5-HT was observed in patients at stage I. Serotonin release from platelets following activation with thrombin was considerably increased in cancer patients (38.2% compared to 17.4% in controls). The results demonstrate progressive depletion of intraplatelet 5-HT in cervical cancer patients. In addition, their platelets release more 5-HT than the controls upon activation by thrombin.
BACKGROUND: Patients with concomitant critical carotid and coronary artery disease are at risk of major neurological events while undergoing coronary artery bypass grafting. The presence of carotid artery stenosis increases the stroke rate in the perioperative period. In an effort to reduce the stroke rate, many institutions perform routine preoperative noninvasive assessment of the carotid arteries. METHODS AND RESULTS: We analyzed the clinical and laboratory data of 1,200 patients who underwent coronary artery bypass surgery in the last 2 years. Carotid Doppler was normal in 186 patients (15.5%), and showed <30% stenosis in 796 (66.3%), 30%-50% in 110 (9.2%), 50%-70% stenosis in 64 (5.3%) and critical (>70%) stenosis in 44 (3.7%) patients. Conventional risk factors such as hypercholesterolemia, hypertension, smoking and family history were not independent predictors of carotid artery stenosis. However, diabetes as a risk factor had a significant association with carotid artery disease (79.6% v. 43.8%, p<0.02). There was a trend towards increased prevalence of carotid artery stenosis in patients with > or = 2 risk factors (84.3% v. 68.8%). Patients with significant carotid artery stenosis had severe coronary artery disease (triple-vessel disease 93.3%, left main coronary artery disease 12.0%). Out of 44 patients with critical carotid artery stenosis, 27 were subjected to carotid angiography. Doppler findings correlated well with angiography. Seventeen patients underwent carotid artery intervention. None had any perioperative neurological events. A total of 5 (0.4%) patients had a major stroke. Coronary artery bypass grafting was done in 27 patients with critical stenosis without any intervention. The stroke rate (11.1%) was higher in these patients compared to patients with < 70% carotid artery disease or post-carotid intervention (2.5%) patients. Thus, untreated >70% carotid artery stenosis was associated with a higher stroke rate. CONCLUSIONS: Doppler screening of the carotid artery is helpful in detecting the subgroup of patients at increased risk of stroke. Patients with critical carotid artery stenosis should be subjected to angiography. Prophylactic intervention may reduce the occurrence of stroke in the perioperative period.