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Biomedical subjects

R D Nichols

Publications and source records attributed to R D Nichols.

At least 19 recordsLinked to original sources
PubMed2000

Use of intraoperative hetastarch priming during coronary bypass.

BACKGROUND: The use of hetastarch during coronary bypass surgery has been limited due to its unresolved potential risk for hemorrhage. Therefore, the purpose of this study was to investigate the effects of using 6% hetastarch in priming cardiopulmonary bypass (CPB) circuitry on the need for blood product transfusions and outcome after coronary bypass. MATERIALS AND METHODS: This nonrandomized retrospective study involved 887 patients who underwent isolated primary coronary artery bypass grafting. Based on the type of solution used in priming the CPB circuitry, patients were stratified into the following four different groups: group 1, crystalloid (500 mL; n = 211); group 2, 25% human albumin (50 mL; n = 217); group 3, 6% hetastarch (500 mL; n = 298); and group 4, 25% human albumin (50 mL) and 6% hetastarch (500 mL; n = 161). Patient characteristics and clinical variables were compared among the groups using the Kruskal-Wallis test. Patient survival estimates were compared using log-rank test. RESULTS: Demographic patient characteristics for all groups were similar (p > 0.05). Intraoperative and perioperative variables among groups were comparable (p > 0.05). The use of hetastarch as a part of prime solution in CPB circuitry did not alter the need for banked blood, platelets, or fresh frozen plasma transfusions (p > 0.05). The length of stay in the ICU or in the hospital was unaffected in all groups. The early (ie, 30-day) mortality rate was 1.4% in group 1, 1.8% in group 2, 1.0% in group 3, and 3.1% in group 4. Long-term survival among the groups was unaffected by the type of priming solution. CONCLUSIONS: The use of hetastarch in priming CPB circuitry is devoid of any added hemorrhagic risk after coronary bypass, and the type of prime solution for CPB has no influence on the early or late survival rates of patients undergoing primary coronary bypass.

Blood Loss, Surgical↗
PubMed2000

Acute renal failure requiring hemodialysis immediately after heart transplantation portends a poor outcome.

BACKGROUND: Previous studies have not provided a definite clarification for the predictive value of pretransplant renal indices on postcardiac transplant patient outcome. Therefore, the purpose of this study was to investigate the interaction between pretransplant renal function and recovery after heart transplantation. METHODS: The study group consisted of 199 consecutive patients who underwent heart transplantation between 1973 and 1994. For better comparison, patients were arbitrarily divided into three different groups based on the year of the transplant operation: Group I- before 1985 (n=13), Group II- between 1985 and 1989 (n=68) and Group III- between 1990 and 1994 (n=118). Values for serum creatinine (Cr), blood urea nitrogen (BUN), urea/creatinine ratio (U/Cr), creatinine clearance (Cr(cl)), length of hospital stay (LOS), early (30-day) mortality, and survival at 1-year and at 5-year were collected for each patient. The data was analyzed by the use of univariate log-rank test with forward stepwise procedure. RESULTS: Postcardiac transplant LOS in the hospital or survival was unaffected by the pretransplant renal indices except the U/Cr ratio (p>0.05). When adjusted for the time, the U/Cr ratio was also insignificant (p=0.1349). The use of hemodialysis was necessary in 9 patients (4.5%) for treatment of acute renal failure manifested immediately after the transplant operation. Early mortality was 44% for these 9 cardiac transplant recipients who required the use of hemodialysis: 0% (0/3) in the 1985-1989 period and 67% (4/6) in the 1990-1994 period. CONCLUSIONS: Pretransplant renal indices have no predictive value on outcome after a heart transplant operation, however, postcardiac transplant acute renal failure necessitating hemodialysis portends a poor outcome.

Acute Kidney Injury↗
PubMed1998

Influence of age-specific lung function on survival after coronary bypass.

BACKGROUND: Respiratory complications after successful coronary artery bypass grafting influence the immediate recovery of a patient; however, whether they influence the longevity of a patient is largely unknown. The aim of this study was to examine the effects of preoperative pulmonary risk factors in younger patients and older patients on outcome after coronary artery bypass grafting. METHODS: A retrospective chart review was performed on 939 patients who underwent primary coronary artery bypass grafting between July 1987 and November 1996. For better comparison, they were arbitrarily divided by age into two groups: group 1, less than 70 years old (n = 710), and group 2, 70 years old or older (n = 229). The variables collected for each patient included history of chronic obstructive pulmonary disease, active smoking, forced expiratory volume, and ventilatory support for more than 48 hours. These variables were compared with postoperative length of stay in the intensive care unit, length of stay in the hospital, and the midterm survival up to 5 years. The data were analyzed by the use of univariate/multivariate log-rank tests and the method of Kaplan-Meier survival estimates. RESULTS: The presence of chronic obstructive pulmonary disease was associated with increased length of stay in the intensive care unit and in the hospital for both groups. Preoperative forced expiratory volume in 1 second, significantly affected length of stay in the hospital only in the patients less than 70 years old (p = 0.0001). Delayed extubation beyond 48 hours of ventilatory support resulted in prolonged length of stay in the intensive care unit and in the hospital for patients less than 70 years old (p = 0.0001, p = 0.0001, respectively) and patients 70 years old or older (p = 0.0001, p = 0.0001, respectively). The 5-year survival after coronary artery bypass grafting for both groups was significantly influenced by the level of preoperative forced expiratory volume in 1 second (p = 0.0004, p = 0.0282, respectively). CONCLUSIONS: Patients with chronic obstructive pulmonary disease, irrespective of age, stay in the intensive care unit and in the hospital longer after coronary artery bypass grafting. In addition, preoperative forced expiratory volume in 1 second is a significant predictor of 5-year survival in the young and aged individuals undergoing coronary artery bypass grafting.

Aged↗
PubMed1998

Long-term survival benefit of internal thoracic artery grafting is negligible in a patient with bad ventricle.

BACKGROUND: Although the internal thoracic artery (ITA) graft is well known for its benefit of enhancing patient longevity after coronary artery bypass grafting (CABG), whether its superior patency is associated with improved patient survival at all levels of left ventricular function is unknown. The purpose of this study was to determine whether the use of ITA grafting during CABG confers improved survival benefit to patients with impaired preoperative left ventricular function. METHODS: A retrospective chart review was performed in 966 patients who had undergone isolated primary CABG between 1984 and 1995. The study population included 320 patients with only venous conduits (no-ITA group) and 646 patients with at least one ITA conduit (ITA group). A Cox partial likelihood approach was used to model the instantaneous mortality risk ratios as functions of ITA use and preoperative ejection fraction (EF). The forward stepwise regression model specifically examined the following potential confounders in the risk analyses: year of operation, patient age, weight, body surface area, graft location, number of grafts, perfusion time, ischemia time and Veterans Administration preoperative cardiac surgical risk estimates. RESULTS: Early (30-day) mortality in the ITA group (0.5%) was lower than the no-ITA group (4.1%) (p=0.0004). While 91% of the ITA group patients were still alive, only 70% of the no-ITA group patients were long-term survivors (p=0.0001). The ITA risk ratios for the increasing proportions of EF were not the same. In patients with E<0.40, the ITA risk ratio, 2.96, was significantly different (p=0.0001). It was only for EF >0.46, a significant survival benefit due to an ITA graft could be detected. The ITA-EF relationship was not confounded by the inclusion of those potential confounding variables in the model. CONCLUSIONS: Patient survival after CABG using an ITA graft may be affected by the level of preoperative EF. The internal thoracic artery-specific patient survival benefit appears to be less in a patient with poor left ventricular function.

Aged↗
PubMed1998

The influence of cardiopulmonary function on outcome of veterans undergoing resectional therapy for lung cancer.

BACKGROUND: The unknown but presumably poor preoperative cardiopulmonary function of U.S. Armed Forces veterans with bronchogenic cancer may dissuade surgeons performing necessary major lung resection. The purpose of this study was to investigate the relationship between preoperative cardiopulmonary risk and the outcome of veterans undergoing pulmonary resection for bronchogenic carcinoma. METHODS: A retrospective chart review was performed on 79 veterans who underwent lung resection for bronchogenic cancer between March 1990 and June 1995. Preoperative cardiac function was assessed by 1) history of heart disease (myocardial infarction, previous open heart surgery, and hypertension), 2) electrocardiogram, EKG, and 3) transthoracic echocardiography, TTE (ejection fraction and left ventricular wall motion abnormalities). Pulmonary reserve was evaluated by 1) history of lung disease (active smoking, known chronic obstructive pulmonary disease, COPD), and 2) spirometry (forced expiratory volume in 1 second, FEV1, and minute ventilation volume, MVV). Resections were performed by standard pulmonary techniques and follow-up data was available in all patients. RESULTS: All patients were males except one, with a mean age of 66+/-1.0 yrs (range=32 to 81 yrs). Fifty-one patients (64.60%) had a history of COPD while one-third of the veterans were smoking and using excessive alcohol just prior to surgery. Twenty-four patients (29%) had abnormal preoperative EKG and only 10 (15%) had prior myocardial infarction. Eleven patients (13.9%) had undergone previous coronary bypass surgery. Average preoperative left ventricular ejection fraction was 63+/-2% (range=41 to 80%) and left ventricular wall motion abnormalities were present in only 6 patients (8%). Mean preoperative FEV1 was 2.2+/-0.1 L (range=0.6-4.1 L) and MW was 87+/-4 L/min (range=26-198 L/min). A lobectomy was performed in 68 patients (86.1%), pneumonectomy in 10 (12.7%), and wedge resection in 1 (1.2%). The most common types of cancer were squamous cell (36 patients) and adenocarcinoma (31 patients). While pulmonary complications (atelectasis, prolonged air leak, pneumonia) occurred in 8 patients (10%), only two (3%) suffered nonpulmonary complications (ischemic bowel disease). For all veterans with bronchogenic cancer, early (30-day) mortality after major lung resection was 3.9% (3/79): 1.5% (1/68) after lobectomy, and 20% (2/10) after pneumonectomy (p=not significant). Overall survival at 5 years was 39.5%. CONCLUSIONS: Preoperative cardiopulmonary risk for veterans with bronchogenic cancer is acceptable and lung resection can be performed with good outcomes in this distinct patient population.

Adult↗
PubMed1997

Assessment of internal thoracic artery vasoreactivity in response to sublingual nitroglycerin.

BACKGROUND: We have previously shown the feasibility of assessing internal thoracic artery (ITA) size and blood flow hemodynamics before and after coronary artery bypass grafting using color-flow duplex ultrasound. This noninvasive method would be an ideal diagnostic tool for the evaluation of ITA graft status after therapeutic interventions in a patient with angina after coronary artery bypass grafting. The purpose of this study was to investigate the effects of nitroglycerin on the diameter and blood flow velocities of the left native ITA before coronary artery bypass grafting and the ITA graft postoperatively. METHODS: The study consisted of 24 male patients (mean age, 59 +/- 2.3 years) who had undergone elective coronary artery bypass grafting using a left ITA graft to the left anterior descending artery, with additional saphenous vein grafts. Color-flow duplex ultrasound (5.0-MHz transducer) was used for both the preoperative imaging of native ITAs and the postoperative study of ITA grafts before patient discharge. Repeated-measures analysis of variance was used to compare measurements of the ITA size and flow velocities (peak systolic velocity and end-diastolic velocity) at 5, 10, and 15 minutes after a single dose of sublingual nitroglycerin (0.4 mg) with the baseline values obtained without nitroglycerin. RESULTS: The preoperative native left ITA and the postoperative left ITA graft diameters responded to sublingual nitroglycerin by showing a rapid and significant increase beginning at 5 minutes and lasting up to 15 minutes (p = 0.0001). Sublingual nitroglycerin caused the peak systolic velocity of the native left ITA to be augmented at 5 minutes (p = 0.0002), and this effect was still apparent at 10 minutes (p = 0.0001) and 15 minutes (p = 0.0192). However, postoperative left ITA graft peak systolic velocities remained unaffected by the sublingual nitroglycerin (p = not significant). CONCLUSIONS: We conclude that instantaneous noninvasive measurement of ITA graft size and blood flow velocities after a therapeutic drug intervention may be clinically useful, particularly in a post-coronary artery bypass grafting patient with recurrent angina.

Administration, Sublingual↗
PubMed1997

Clinical importance of measuring coronary graft flows in the revascularized heart. Ultrasonic or electromagnetic?

BACKGROUND: In the past, routine coronary graft flow measurement at the end of coronary artery bypass grafting (CABG) was not universally adopted by cardiac surgeons due to the lack of reliable flow measurement techniques. The purpose of this study was to investigate the efficacy of ultrasonic and electromagnetic techniques in coronary graft flow measurements and to determine the relationship, if any, between intraoperative ultrasonic or electromagnetic coronary graft flows and postoperative early clinical outcome. METHODS: We studied 66 consecutive patients who underwent elective CABG using internal thoracic artery (ITA) and reversed saphenous vein graft (SVG) conduits. All patients were males with the mean age of 65 +/- 1 yrs (range = 45 to 80 yrs). Coronary bypass graft flows (both ITA and SVG) were determined by the use of both ultrasonic and electromagnetic flowmeters. In addition, the flow waveform pattern was continuously recorded and analyzed with the ultrasonic technique. In this prospective non-randomized study, the following variables were considered in the forward stepwise multivariate regression analysis of the data: age, weight, body surface area, ejection fraction, perfusion and ischemia times, number of grafts, amount of allogenic banked blood, platelets, fresh frozen plasma transfusions, cardiac output/index, ultrasonic (USF) and electromagnetic flows (EMF), length of intensive care unit (ICU) and hospital stays, and early (30-day) mortality. RESULTS: Based on their location, 226 grafts were divided into four groups: (I) ITA to left anterior descending (LAD) (n = 66) 34 +/- 2.5 ml/min USF and 45 +/- 4.4 ml/min EMF; (II) SVG to circumflex (CX) (n = 62) 33 +/- 2.4 m/min USF and 58 +/- 4.9 ml/min EMF; (III) SVG to diagonal (DIAG) (n = 37); 30 +/- 3.5 ml/min USF and 50 +/- 6.0 ml/min EMF; (IV) SVG to right coronary artery (RCA) (n = 61); 36 +/- 3.1 ml/min USF and 56 +/- 5.3 ml/min EMF. Electromagnetic flow measurements were higher than USF values in all locations (p < 0.05). Difficulties in obtaining proper contact with the vessel wall and finding suitable size probes were major drawbacks in measurement of ITA graft flow by the use of electromagnetic technique. All flow measurements were done within 10 minutes or less. There was no demonstrable correlation between the length of stay (ICU and hospital), and coronary graft flows at the ITA to LAD, SVG to DIAG, or SVG to CX locations. However, ultrasonic coronary graft flows at the SVG to RCA location had a significant inverse correlation with the length of ICU and hospital stays (r = -0.45, p < 0.0005 for both). Early mortality was unaffected by the intraoperative coronary graft flow values (p = NS). CONCLUSIONS: The ultrasonic flowmeter is well-suited for intraoperative assessment of arterial and venous coronary graft flows at the completion of CABG. There is a real potential for using intraoperative graft flow values to predict early outcome after coronary bypass.

Aged↗
PubMed1996

Influence of increasing age on long-term survival after coronary artery bypass grafting.

BACKGROUND: Despite the steady increase in the number of elderly patients undergoing coronary artery bypass grafting (CABG), skepticism still exists as to whether this operation is justified in older people with a reduced life expectancy. The purpose of this study was to examine the effects of increasing age on outcome after CABG. METHODS: A retrospective chart review was performed on 1,689 consecutive veterans of the United States Armed Forces undergoing isolated primary CABG from January 1972 through December 1994. For better comparison, they were arbitrarily divided by age into three groups: group I, 50 years of age or less (n = 213), group II, between 51 and 70 years of age (n = 1,258), and group III, more than 70 years of age (n = 218). Long-term survival for each group was compared to that of their age-matched population derived from Wisconsin life tables. RESULTS: The preoperative ejection fraction was comparable in all three groups (p = 0.114). The patients older than 70 years of age had received more grafts per operation than the patients 50 years of age and younger (3.7 versus 3.3) (p = 0.0001). Although the aortic cross-clamp time was prolonged with advanced age (p = 0.0002), the cardiopulmonary perfusion time was shortest in elderly patients (p = 0.0001). The early (30-day) mortality for the entire study population was 1.3%. There was a linear correlation between increasing age and early (30-day) mortality: group I, 0.5% (1/213); group II, 1.0% (13/1,258); and group III, 3.2% (7/218). The overall 10-year actuarial survival for all patients was 67%. The 10-year survival was diminished with increasing age (p = 0.0001): 74% for group I, 68% for group II, and 47% for group III. Comparative analysis of the three groups with their age-matched counterparts demonstrated an age-related survival after CABG. In group I, reduced survival was evident 4 years after the CABG: the 10-year survival in group I was 74.2%, and the survival of their age-matched population was 93.4% (confidence interval, 67% to 81.9%). In group II a survival difference was obvious 8 years after CABG: 10-year survival of 67.5% versus 75.1% in their age-matched population (confidence interval, 64.8% to 71.6%). In the elderly group of patients, no survival difference was noted: 10-year survival of 42.7% versus 45.9% of the age-matched population (confidence interval, 29.8% to 64.6%). CONCLUSIONS: An acceptable early mortality and long-term survival equal to those seen for an age-matched elderly population are sound outcome measures that support the justification of CABG in older patients irrespective of age.

Adult↗
PubMed1996

Tympanostomies with tubes: the parent perspective.

Successful physician-patient encounters satisfy patient and family member needs beyond the effect on the disease process itself. To evaluate that aspect of care in children with chronic and recurrent acute otitis media with effusion, surveys regarding perceptions of health, socioeconomic issues, and other aspects of postoperative status were sent to the parents of 637 children who underwent tympanostomies with tubes in 1994. Three hundred one (47.3%) were returned. Responses included perceptions of improved health (87%), improvement in socioeconomic factors (75%), overall satisfaction with the results of the operation (93%), and willingness to consent to the operation given similar problems in another child (87%). There were no significant differences in responses with regard to patient gender, length of follow-up, or multiple operations. These results suggest that patient and family needs are satisfied by tympanostomies with tubes.

Adolescent↗
PubMed1995

Accelerated fractionation radiotherapy and concomitant chemotherapy in patients with stage IV inoperable head and neck cancer.

BACKGROUND: Stage IV inoperable head and neck cancer has a 2-year mortality rate of greater than 70% when treated with conventional radiotherapy. A Phase II study was undertaken to evaluate the effects of concomitant chemotherapy and accelerated, interrupted, twice-a-day radiotherapy on tumor response, locoregional control, survival, and morbidity. METHODS: Thirty-four patients with Stage IV inoperable squamous cell carcinoma of the head and neck and a minimum follow-up of 36 months were evaluated. Concomitant chemoradiotherapy was administered during weeks 1, 3, and 5 (with planned breaks during weeks 2 and 4), consisting of cisplatin 60 mg/m2 on day 1, continuous 5-day infusion of 5-fluorouracil, 750 mg/m2 per day, and radiotherapy, 2 Gy twice a day, more than 6 hours apart, followed by 3 days of radiation therapy alone (final "boost") in week 6, for a total dose of 70 Gy and treatment duration of 5 1/2 weeks (38 days). RESULTS: Twenty-seven patients achieved a clinical complete response (82%). Actuarial locoregional control at 3 years was 73% and the actuarial 3-year survival probability, including all deaths, was 38%. All locoregional recurrences were manifested within 12 months. Of the 20 deaths, 12 were tumor related (locoregional and/or metastatic), 3 were treatment related, and 5 were due to other causes. Acute toxicity consisted of grade 3 mucositis and dysphagia and grade 2-3 leukopenia, not requiring treatment interruption or cessation. CONCLUSION: Concomitant accelerated radiation therapy and chemotherapy is a feasible treatment approach in this prognostically poor patient population, yielding dramatic tumor responses and impressive locoregional control at the cost of somewhat increased acute toxicity. Although serious late complications have not been observed, caution should be exercised in view of the relatively short follow up.

Adult↗
PubMed1995

Color-flow duplex ultrasound assessment of internal thoracic artery graft after coronary bypass.

In an effort to develop a noninvasive method to evaluate flow characteristics of the internal thoracic artery (ITA) graft after coronary artery bypass grafting, we performed color-flow duplex ultrasound studies of the right and left ITAs of 42 patients before and 5 weeks after bypass grafting. The ITA was visualized with a duplex scanner (5.0-MHz probe) through the first or second intercostal space. We recorded the diameter, peak systolic velocity, and end-diastolic velocity for each patient. Preoperative measurements of the native ITAs were obtained easily in all patients. Postoperatively, the unused right ITA was seen in all patients. Postoperative visualization of the left ITA graft was adequate to make reliable measurements in 40 patients (95%). Postoperative end-diastolic velocities of the unused right ITA and the left ITA graft were markedly higher than the preoperative end-diastolic velocities of the native ITAs (p < 0.001). Whereas there was a marked increase in the peak systolic velocity of the postoperative unused right ITA (p < 0.05), the postoperative peak systolic velocity of the left ITA graft was significantly lower than the preoperative value (p < 0.001). We conclude that postoperative visualization of the left ITA graft is possible with the use of color-flow duplex ultrasound. Ultrasonic surveillance of postoperative ITAs may reveal ITA graft velocity abnormalities before overt graft failure is manifested in the patient who has undergone coronary artery bypass grafting.

Adult↗
PubMed1995

Management guidelines for improvement of otolaryngology referrals from primary care physicians.

OBJECTIVE AND DESIGN: A prospective evaluation of the effectiveness of otolaryngology evaluation, treatment, and referral guidelines developed collaboratively by otolaryngologists and primary care physicians on referrals and access to otolaryngology. Comparisons of appropriate to unnecessary referrals, the percentage of patients referred with disorders addressed to those without disorders addressed in the guidelines, access to otolaryngology, and questionnaire evaluations of primary care physician and patient satisfaction were measured before and after guideline implementation. RESULTS: A significant decrease in appropriate to unnecessary referrals was seen, from 55% before to 12% after guidelines. The percentage of patients seen within 1 month of scheduling improved from 39% to 59%. Guideline-addressed disorders decreased from 63% to 40%. The need for patients to see another physician for the referred symptom while waiting to see an otolaryngologist decreased from 31% to 3%. Patient satisfaction with wait times improved. Eighty-six percent of the primary care physicians used the guidelines, and 85% wanted to expand the guidelines to other specialty areas. CONCLUSIONS: Management and referral guidelines are effective in improving patient access and the ratio of appropriate to unnecessary referrals. Such guidelines are well accepted and used by primary care practitioners in this setting.

Appointments and Schedules↗
PubMed1995

The effects of intraoperative autologous whole blood sequestration on the need for transfusion of allogenic blood and blood products in coronary bypass operations.

We investigated the effect of intraoperative autologous blood sequestration (IABS), an old blood conservation method, on transfusion requirements for homologous packed red blood cells (PRBC), platelets, and fresh frozen plasma (FFP) for patients undergoing coronary bypass surgery. This non-randomized retrospective study involved 204 patients who underwent isolated primary coronary artery bypass grafting (CABG). In 140 patients (IABS Group), autologous heparinized whole blood was removed intraoperatively via aortic cannula before bypass and retransfused at the conclusion of extracorporeal circulation. In 64 control patients, no IABS was performed. Demographic characteristics and operative and perioperative variables for both groups were similar (p > 0.05). In 140 patients, the mean sequestered blood volume was 1430 ml (range = 700-2100 ml). The banked PRBC requirement during hospitalization was 1.91 units in the No IABS Group and 2.25 units for the IABS Group (p = 0.2957). The need for platelet transfusion was 3.06 units in the No IABS Group and 1.09 units in the IABS Group (p = 0.0003). In the No IABS Group, 1.31 units of FFP was transfused and in the IABS Group, 0.49 units was transfused (p = 0.0004). To identify possible confounding factors, we performed a multivariate Poisson regression analysis for the 22 patient variables by a forward stepwise procedure. Regression analysis indicated that IABS did not alter the need for PRBC transfusion (p = 0.6194) but adjusted differences did confirm that IABS was associated with decreased need for transfusion of platelets and FFP (p = 0.0001 and p = 0.0002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous↗
PubMed1994

Intracellular modulation of acid secretion in rat inner medullary collecting duct cells.

In this study we defined some of the important elements in the acidification process of rat inner medullary collecting duct (IMCD) cells in culture. After cell acidification, i.e., cell pH (pHi) = 6.51 +/- 0.02, pHi increased 0.046 +/- 0.003 units/min. N-ethylmaleimide, N,N'-cyclohexylcarbodiimide, and bafilomycin reduced this rate by over 85%. In contrast, omeprazole and Sch-28080 had no effect. 1,2-Bis(2-aminophenoxy)ethane-N,N,N,N'-tetraacetic acid, which prevents a rise in cell Ca2+ concentration ([Ca2+]i) reduced the rate of pHi recovery to 0.013 +/- 0.002 units/min. Calmodulin inhibitors or disruption of cytoskeletal elements with cytochalasin B and colchicine also reduced pHi recovery significantly. In addition, these cells contain acidic vesicles and undergo pHi-regulated endocytosis and exocytosis, which are inhibited by disrupting the cytoskeleton. We conclude that, in our cultured line of rat IMCD cells, proton secretion is mediated by an H(+)-adenosinetriphosphatase. Changes in pHi produce alterations in acid secretion through a signal cascade that requires changes in [Ca2+]i, activation of calmodulin, an intact cytoskeleton, and alteration in the rate of exocytosis and endocytosis.

Acids↗
PubMed1993

Alveolar consolidation detection: advanced multiple beam equalization radiography versus conventional chest radiography.

Advanced multiple beam equalization radiography (AMBER) and conventional chest radiography were prospectively evaluated in the detection and quantitation of alveolar (air-space) consolidation. Thirty-seven healthy volunteers underwent bronchoalveolar lavage (BAL), the retained lavage fluid serving as a model for alveolar consolidation. After BAL, the subjects underwent AMBER and conventional chest radiography. The lower lung zones on the radiographs were divided into four zones and graded for alveolar consolidation by three observers. There was no significant difference in the area under the receiver operating characteristic curve between the two techniques in the detection of lavage fluid. The grade of opacification was rated significantly higher (P < .05) on conventional radiographs for three of the four lung zones examined, and the correlation between the quantity of retained lavage fluid and grade of opacity was better on conventional radiographs. Detection of lavage fluid was poor with either technique. The exposure compensation of AMBER was evident in this model of air-space disease but did not affect overall observer performance.

Adult↗
PubMed1991

Partial laryngectomy after irradiation failure.

Forty-three patients who had partial laryngectomies after radiotherapy were evaluated. Forty-two had failed irradiation for laryngeal carcinoma. Nine had supraglottic procedures, 3 endoscopic, and 31 vertical partial. Twelve (28%) required subsequent completion laryngectomy. Major complications included laryngeal stenosis in 1, incompetent laryngeal sphincters in 2, mucocutaneous fistulas in 3, and delayed deglutition in 3. Six patients had positive permanent section margins. In 5 of those, intraoperative frozen sections had been taken and were negative. Recurrent or persistent disease was eventually demonstrated in all patients with positive margins. The 2-year determinant disease-free survival rate for stage I and II disease was 85%. Three-year disease-free survival was 50% for stage III and IV disease. Partial laryngectomies, including supraglottic, can be done after irradiation failure with a high expectation of cure and acceptable morbidity. Immediate additional operation should be considered in patients with positive margins.

Adult↗
PubMed1990

Denker rhinotomy for inverted papilloma of the nose and paranasal sinuses.

Inverted papilloma of the nose and paranasal sinuses is an unusual benign neoplasm that has the propensity for local tissue destruction and an association with malignant degeneration. The tumor represents an inverted growth of epithelium rather than outward proliferation. It most commonly arises from the lateral nasal wall with growth into the nose and paranasal sinuses and only rarely originates from the septum. Presenting symptoms are usually unilateral nasal obstruction and clear rhinorrhea. Surgical excision is the recommended treatment though the aggressiveness of the approach has varied. Transnasal local excision has been associated with a high recurrence rate. Lateral rhinotomy with removal of the lateral nasal wall and wide local excision has a low recurrence rate and has been the recommended treatment by most authors since 1980. However, the poor cosmetic results in some patients due to the visible external scar is especially undesirable in young females. We present a series of 23 patients treated over a ten-year period. Fifteen underwent a Denker rhinotomy and medial maxillectomy through a sublabial approach without an external incision. The recurrence rate in our group is 27% with a mean 4.7 year follow-up. This recurrence rate lies between that reported for lateral rhinotomy and local transnasal excision.

Adult↗