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Biomedical subjects

R Pillai

Publications and source records attributed to R Pillai.

At least 73 records · Page 4Linked to original sources
PubMed1993

Stentless aortic bioprosthesis? The way forward: early experience with the Edwards valve.

Tissue valve degeneration has been variably attributed to preservation and fixation methods. Additionally, a rigid valve ring might contribute to valve failure. The use of a nonstented porcine valve in the aortic position has clear hemodynamic advantages, and the lack of a stent may favorably influence long-term function. We have implanted stentless aortic valves (Prima valve) in 31 patients. There were 17 men. The mean age was 71.5 years (range, 50 to 83 years). After sculpturing of the sinuses the valve is positioned below the coronary arteries. Valve sizes ranged from 19 to 27 mm. There were no early or late deaths. Mean follow-up to date is 8.9 months (range, 4 weeks to 15 months). Early hemodynamic follow-up using Doppler echocardiography shows average peak systolic and mean gradients of 20.4 mm Hg and 8.6 mm Hg, respectively, at 4 weeks in 26 patients, with no significant change in 13 patients at 6 months. All patients are currently in New York Heart Association class I or II. Our early experience of stentless aortic valves shows them to be reliable with a satisfactory early hemodynamic profile. Their use in the elderly may conserve homografts for children and the young.

Aged↗
PubMed1993

Continuous retrograde cerebral perfusion during an aortic arch operation.

An 81-year-old woman presented with acute aortic regurgitation in the setting of an aneurysm of the ascending aorta and arch. The aortic valve, ascending aorta, and arch were replaced with a composite graft during continuous hypothermic total-body perfusion. Continuous cerebral perfusion was carried out by low-pressure retrograde perfusion via the superior vena cava while perfusion of the lower body was maintained via a femoral arterial cannula.

Aged↗
PubMed1993

Synthesis and biochemical studies of estrone sulfatase inhibitors.

The synthesis and biochemical evaluation of estrone sulfatase inhibitors are described. Inhibitors were designed through modifications of the substrate estrone sulfate. An in vitro assay using the microsomal fraction isolated from human term placenta was used to evaluate sulfatase inhibitory activity. All the inhibitors (except sulfonyl chloride analog) exhibited low inhibitory activities in the screening assay. Sulfonyl chloride analog is a strong inhibitor, which caused 91.5% inhibition of the enzymatic activity at 300 microM.

Estrenes↗
PubMed1993

Systemic inflammatory responses to cardiopulmonary bypass: a pilot study of the effects of pentoxifylline.

The potential of pentoxifylline (PTX) to modify systemic inflammatory responses and lung injury following cardiopulmonary bypass (CPB) was studied in 20 patients undergoing elective coronary artery surgery. Ten control patients were compared with ten patients who received a PTX infusion of 1 mg kg-1 h-1 during surgery. Intra-vascular pulmonary leukocyte sequestration was observed in neither group following discontinuation of CPB. Plasma elastase-alpha-1-antiprotease complex rose three-fold from baseline in both groups to peak at sternal closure. No significant plasma interleukin-1 (IL-1) response was detected. Plasma interleukin-6 (IL-6) rose in both groups from baseline to peak 4 h postoperatively. There was no correlation between plasma levels of elastase complex, IL-1 or IL-6 and impairment of postoperative oxygenation. CPB was associated with significant postoperative hypoxaemia and systemic release of neutrophil elastase and IL-6 but PTX, at the given dose, did not abrogate these responses.

Cardiopulmonary Bypass↗
PubMed1993

Atrial fibrillation after coronary artery bypass grafting: a comparison of cardioplegia versus intermittent aortic cross-clamping.

Supraventricular tachyarrhythmias following coronary artery bypass grafting are a common cause of postoperative morbidity, with a reported incidence of 10-40%. Two techniques of myocardial protection were assessed to determine their influence on the occurrence of postoperative supraventricular tachyarrhythmias. Group I (n = 82) received cold potassium cardioplegia combined with topical hypothermia and systemic cooling to 28 degrees C. Group II (n = 88) were protected by intermittent aortic cross-clamping with a systemic temperature of 32 degrees C. The overall incidence of atrial fibrillation/flutter was 22.3%. No significant difference was detected in the incidence of clinically important atrial fibrillation/flutter between the two groups [21/82 (25.6%) in group I versus 17/88 (19.3%) in group II, P > 0.25]. There was a positive association with age: in patients over 60 years the incidence of arrhythmias (31.8%) was significantly greater than in those less than 60 years (12.9%), P < 0.01. Sex, cardiopulmonary bypass times, aortic cross-clamp times, number of coronary grafts, end-operative creatine kinase myocardial band isoenzyme, right coronary endarterectomy and perioperative myocardial infarction had no association with the occurrence of postoperative atrial tachyarrhythmias.

Atherectomy, Coronary↗
PubMed1993

Does modern cardiac surgery require conventional intensive care?

We considered that, with modern perfusion equipment and mildly hypothermic cardiopulmonary bypass, protracted post-operative ventilation in an intensive care unit (ITU) is no longer required after most cardiac operations. We used a three-bedded cardiac recovery area (CRA) within the operating suite for 1,000 patients between January 1990 and June 1991. Forty-five patients with special needs were managed in the ITU. The time to extubation (T50%; range) for coronary bypass, aortic valve, mitral valve, and double-valve patients was 2.0 (0-42), 2.5 (0-12), 3.0 (0-15), and 3.0 (1-36) hours, respectively. Recovery beds were re-used allowing 5-6 operations daily. The difference in nursing staff complement for a CRA versus ITU bed was 4.5/7.8. Patient management was by nurse specialists supported by cardiac surgeons. Intervention by cardiac anaesthetists or intensivists was limited to specific ventilatory problems or renal failure. The early extubation policy failed in ten patients (five coronary, three aortic, one mitral and one double-valve patient) through poor pre-operative respiratory function, left ventricular failure or intra-operative events. The overall mortality in CRA was 1.4%. The mean duration of post-operative stay was 7 days (range 5-12). We conclude that a CRA staffed by nurse practitioners provides a safe and effective alternative to the anaesthetist-managed ITU. A rapid turnover of CRA beds removes the constraints of ITU bed availability.

Adolescent↗
PubMed1993

The effect of a cardiac surgical recovery area on the timing of extubation.

The anesthetic and postoperative management of cardiac surgical patients was modified to achieve an early return to spontaneous ventilation. A total of 278 patients were studied to determine the effect of this change. Patients in group I (n = 198) were managed in a cardiac surgical recovery area according to the new policy. Group II (n = 80) was a comparable group of patients operated upon before this change. The median duration of postoperative ventilation was reduced from 5 hours in group II to 1 hour in group I, and the time to extubation was reduced from 7 hours to 2 hours, respectively. There were no major postoperative complications resulting from this change. The factors that influence the duration of postoperative ventilation are discussed.

Adult↗
PubMed1993

Replacement of the thoracic aorta with collagen-impregnated woven Dacron grafts. Early results.

We used the collagen-impregnated woven double-velour Dacron graft in 120 patients undergoing 122 aortic reconstructions. Seventy-nine aortic root, ascending, or arch replacements were performed during cardiopulmonary bypass with or without circulatory arrest; 53 of the 79 were for acute aortic dissection. In addition, three infants and one child underwent repair of truncus arteriosus. There were no deaths caused by hemorrhage or bleeding-related complications. For aortic root replacement, the impervious nature of the collagen-impregnated woven double velour Dacron graft allowed elimination of wrap-around techniques. Eight deaths occurred as a result of multisystem organ failure, which followed late diagnosis of type A dissection. Two patients underwent reoperation for late complications of type A dissection. Thirty-nine patients underwent treatment for disease of the descending aorta; eight of these patients underwent a central cannulation technique with profound hypothermic cardiopulmonary bypass. The other 31 underwent repair with aortic crossclamping without bypass. Four of these patients died: two as a result of multisystem organ failure, one as a result of uncontrolled bleeding from the native dissected aorta, and one as a result of intestinal necrosis. Follow-up studies for 2 months to 5 years revealed three late deaths caused by the rupture of a persistent aneurysmal false lumen after type A dissection. The intraoperative advantages of the collagen-impregnated woven double velour Dacron graft represent an important advance in vascular graft technology. Its handling and suturing characteristics are excellent, and the graft is completely impervious in its originally manufactured state. Needle holes self-seal rapidly. Medium-term follow-up by clinical, angiographic, computed tomographic, and magnetic resonance imaging techniques showed no late graft complications--specifically, no dilatation or thrombus formation.

Adult↗
PubMed1993

Effect of cardiopulmonary bypass on systemic release of neutrophil elastase and tumor necrosis factor.

Leukocyte counts, plasma neutrophil elastase, tumor necrosis factor-alpha and C-reactive protein were determined serially in 19 patients undergoing elective coronary artery surgery with cardiopulmonary bypass. Neutrophil counts (mean +/- standard deviation 3.85 +/- 1.20 x 10(9)/L preoperatively) peaked 4 hours postoperatively at 10.35 +/- 4.24 x 10(9)/L (p < 0.001) and remained significantly elevated 48 hours postoperatively at 7.80 +/- 2.70 x 10(9)/L, p < 0.05. Plasma neutrophil elastase level (187 +/- 74 ng/ml preoperatively) peaked at 698 +/- 323 ng/ml at the end of surgery (p < 0.001) and remained significantly elevated at 424 +/- 146 ng/ml 48 hours postoperatively (p < 0.01). Peak elastase levels correlated significantly with duration of bypass (r = 0.47, n = 19, p < 0.05). Monocyte counts (0.29 +/- 0.19 x 10(9)/L preoperatively) peaked 4 hours postoperatively (0.87 +/- 0.41 x 10(9)/L, p < 0.001) and fell to baseline levels by 48 hours postoperatively. Plasma tumor necrosis factor-alpha, detectable in 10 of the 19 patients preoperatively (median 0.39 U/ml, range up to 10.1 U/ml), did not change significantly during or after bypass. Plasma C-reactive protein level (median 1.67 [range 0.69 to 34.33] micrograms/ml preoperatively) rose significantly to 3.99 (range 1.95 to 12.55) micrograms/ml 4 hours postoperatively (p < 0.01) and rose 48 hours postoperatively at 303 (210 to 410) micrograms/ml, p < 0.001. Oxygenation, determined by the respiratory index, was impaired at the end of operation (2.07 +/- 0.82) and remained impaired 24 hours postoperatively (2.48 +/- 0.83). Impairment of oxygenation was temporally related to elevated elastase levels, but neither peak elastase levels nor the change in elastase levels with lung reperfusion correlated significantly with the area under the respiratory index curve up to 6 hours postoperatively. This study demonstrates neutrophil elastase release during cardiopulmonary bypass but fails to show a definite role for neutrophil activation or tumor necrosis factor-alpha in the etiology of pulmonary dysfunction after cardiopulmonary bypass.

Aged↗
PubMed1992

Role of immune response in the prognosis of carcinoma of the uterine cervix: can in vitro analysis provide a better framework for more effective management?

Cancer of the uterine cervix is the single largest female malignancy in India and also remains a major problem facing oncologists in other parts of the world. While advances in radiation therapy and surgical techniques have made the treatment of cervical carcinoma impressive, limitations to successful management still remain. In fact, the 5-year survival rate, stage for stage, has not improved in the United States or world wide in the past 40 years. With an estimated half a million women developing this disease annually, this lack of improved survival poses an international unresolved health problem. Immune response has been shown to be a major factor involved in the course of the disease for this cancer. Immunologic monitoring was also shown to be of effective value in assessing the prognosis for cervical carcinoma. We studied the various immunologic abnormalities in cervical cancer, the effects of radiation therapy on immune function, prospects of an immunologic staging system, the relationship between human papillomavirus infection and the immune response, and the possibility of using in vitro immunologic assessment to provide a better framework for more effective management of cancer of the uterine cervix.

Antibody Formation↗
PubMed1992

Pathogenesis of oral submucous fibrosis. Relationship to risk factors associated with oral cancer.

Oral submucous fibrosis (OSF) is a chronic disease of the oral mucosa characterized by inflammation and a progressive fibrosis of the lamina propria and deeper connective tissues. It is a condition predominantly seen among people of Indian origin, and an epidemiologic survey done a decade ago showed no less than 250,000 cases in India, a figure that must have increased sharply. OSF is a condition with a high risk of malignant transformation; to date, no conclusive etiologic agent has been identified, although plenty of data have been generated on various aspects of the disease. These include genetic, carcinogenic, immunologic, viral, nutritional, and autoimmune possibilities, all of which also have been implicated in the development of oral cancer. This article reviews existing evidence on the pathogenesis of OSF and its relation to oral cancer and suggests a possible multifactorial model to explain the disease process.

Humans↗
PubMed1992

Biological monitoring of cancer chemoprevention.

A major limiting factor in the successful implementation of cancer chemoprevention trials has been the determination of endpoints to measure efficacy and success. The use of the ultimate goal of such trials, namely, cancer incidence, as an endpoint has serious feasibility problems, including the need for large numbers of participants, long follow-up periods, and high costs. The application of biological markers as intermediate endpoints to reveal responses to chemopreventive agents within a short time and to act as surrogates for cancer is an attractive concept worthy of intense investigation. This study reviews some potential biological markers, including genetic, cellular, biochemical, and immunological, as well as their possible application to cancer chemoprevention.

Antineoplastic Agents↗
PubMed1992

Cytokine responses to cardiopulmonary bypass with membrane and bubble oxygenation.

The systemic inflammatory response to cardiopulmonary bypass was assessed in 20 patients who underwent elective coronary artery bypass grafting with flat-sheet membrane oxygenation (group I; n = 10; age, 59 +/- 5 years) or bubble oxygenation (group II; n = 10; age, 62 +/- 8 years). The duration of cardiopulmonary bypass was 46 +/- 12 minutes in group I and 47 +/- 15 minutes in group II. Plasma interleukin-6, plasma interleukin-1 beta, transpulmonary leukocyte counts, pulmonary hemodynamic variables, and respiratory index were determined in all patients perioperatively. The plasma interleukin-6 response (median [range]) was similar in both groups at the end of the operation, peaked 4 hours postoperatively (99 [30 to 320] pg/mL in group I; 123 [21 to 300] pg/mL in group II; p greater than 0.05), and remained elevated 48 hours postoperatively (76 [9 to 140] pg/mL in group I; 65 [25 to 159] pg/mL in group II; p greater than 0.05). No significant interleukin-1 beta response was demonstrated. Pulmonary neutrophil and lymphocyte sequestration was observed on commencement of cardiopulmonary bypass in group II but did not occur in either group on discontinuation of cardiopulmonary bypass. Pulmonary vascular resistance at the end of the operation (82 [48 to 320] dynes.s.cm-5 in group I; 119 [54 to 385] dynes.s.cm-5 in group II; p greater than 0.05) was similar to preoperative values (151 [30 to 327] dynes.s.cm-5 in group I; 185 [62 to 291] dynes.s.cm-5 in group II; p greater than 0.05). The respiratory index at the end of the operation was similarly and significantly increased in both groups (1.26 [0.92 to 4.17] in group I; 1.44 [0.73 to 3.30] in group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Oncogenesis of squamous carcinoma of the uterine cervix.

Carcinoma of the uterine cervix is the most frequent neoplasm among women in India, accounting for up to 85% of all female gynecological malignancies. In the United States, it accounts for about 48% of all female tumors and 4% of all cancer deaths of females. Epidemiological evidence suggests involvement of numerous risk factors in the etiology of cervical cancer, including sexual behavior, number of pregnancies, cigarette smoking, and venereal disease. Recent studies, however, tend to emphasize viral involvement in the development of cervical cancer along with concomitant cytogenetic and immunological changes. This review focuses on the roles of human papillomavirus infection, chromosomal abnormalities, and immune function changes in the pathogenesis of cervical carcinoma.

Carcinoma, Squamous Cell↗
PubMed1992

Cardiac surgery: moving away from intensive care.

OBJECTIVE: To evaluate outcome in patients managed outside an intensive care unit after open heart surgery. BACKGROUND: The high cost of cardiac surgery is mainly due to the needs of traditional postoperative care. The requirements for intensive care and treatment has decreased with improvements in techniques of cardiac surgery and anaesthesia. In this setting the need to continue to depend on intensive care units for the recovery of cardiac surgical patients is questionable on clinical and economic grounds. DESIGN: Postoperative outcome in 245 patients over a four month period was studied prospectively. PATIENTS: Mean age of the patients was 63.2 years. They underwent a wide variety of operative procedures. Ninety percent of them recovered in a dedicated three bed cardiac surgical recovery area where the management protocol led to rapid extubation and step down in dependency care. RESULTS: Median time for ventilatory support was 90 minutes after transfer to the area. Only five patients were subsequently admitted to the general intensive care unit for prolonged respiratory and cardiac support. Ten patients were electively admitted to the general intensive care unit. Two deaths occurred in hospital in this group (0.8%). Four patients were ventilated for 24 hours in the recovery area itself and made an uncomplicated recovery. CONCLUSION: This study confirms that over 90% of patients undergoing cardiac surgery would recover safely and be treated effectively in a more economical area than intensive care.

Adult↗
PubMed1992

Aortic root replacement: modifications of technique with improvements in technology.

Potential morbidity remains substantial in aortic root replacement. The tissues are often fragile, contributing to the risk of haemorrhage and postoperative complications. In the past surgery has been directed towards minimising haemorrhage by wraparound techniques and the right atrial fistula method of Cabrol. However, recent use of aortic homografts, collagen-impregnated grafts and tissue glues have reduced bleeding and simplified operative technique. Profound hypothermia and total circulatory arrest allows aneurysm resection to extend into the aortic arch. Between 1986 and 1991 25 aortic root replacements were carried out at the Oxford Heart Centre in 21- to 76-year-olds, 13 for aorto-annular ectasia (4 due to Marfan's syndrome), 7 for aortic dissection (2 Marfan's syndrome) and 2 for complications of previous aortic valve replacement. Three patients had homograft root replacement for aortic root endocarditis. We implanted 14 Medtronic composite grafts, 1 St Jude conduit and 7 collagen-coated Dacron grafts (Hemashield, Meadox) into which a Starr-Edwards valve was sewn, as well as 3 homografts. One patient with a massive chronic dissection following previous aortic valve replacement required an interposition graft to the coronary ostia. In the others, the coronary ostia were mobilised from the native aorta and directly implanted into the conduit. In dissections a ring of pericardium or GoreTex was used to buttress the coronary anastomoses. Six patients also required coronary artery grafting. Native aorta was excised and not wrapped around the conduit. Coagulation defects were corrected aggressively with platelets, fresh frozen plasma and cryoprecipitate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Combined cardiac and abdominal aortic aneurysm operations. The dual operation on cardiopulmonary bypass.

Eight patients underwent both cardiac operation and repair of abdominal aortic aneurysm. All had respiratory impairment and significant impairment of left ventricular function, whereas six patients had severe diffuse distal coronary disease. In all patients the cardiac procedure was performed first, and the patients continued to receive cardiopulmonary bypass. Rewarming was not commenced until the abdominal repair was well under way, to protect the vital organs. There were no problems in weaning the patients from bypass, and six of the patients were extubated within 24 hours; one required ventilation for 36 hours. One patient died of colonic infarction complicated by kidney failure without being extubated. Another patient who was initially extubated in 11 hours required reintubation because of poor lung function and eventually died of multisystem organ failure caused by bilateral lower limb ischemia that persisted despite embolectomies. All survivors are well and in New York Heart Association functional class I or II between 3 and 18 months postoperatively. We conclude that for patients considered unfit for abdominal aortic aneurysm operations because of the nature of the cardiac disease, the combined operation with cardiopulmonary bypass is both safe and effective.

Aged↗