Biomedical subjects

Y Shyr

Publications and source records attributed to Y Shyr.

At least 73 records · Page 4Linked to original sources

PubMed1998

The significance of microabscesses in liver transplant biopsies: a clinicopathological study.

Parenchymal microabscesses (MA) in liver transplant biopsies are frequently associated with cytomegalovirus (CMV) infection. However, other potential causes of MA have not been fully investigated. We studied additional etiologies for MA via histological evaluation and clinicopathological correlation. Three hundred seventy-two liver transplant biopsies from 97 patients (from 1991 to 1997) were reviewed and stained immunohistochemically for CMV. Numerous histological features were evaluated including size and number of MA, lobular and portal inflammation, and cholestasis. Medical records were reviewed for radiographic, laboratory, and other clinical data from the time of biopsy. The chi2 or Fisher's Exact test and ANOVA with adjusted multiple comparisons were used to determine statistical significance. Sixty-two of 372 biopsies (17%) from 43 patients contained MA. Biopsies were obtained between 4 days and 2.3 years posttransplant (median, 14 days). Nineteen percent of biopsies had CMV infection at the time of biopsy; 27% were associated with other bacterial, viral, or fungal infections; 10% had graft ischemia; 15% had biliary obstruction/cholangitis; 3% had a combination of ischemia and sepsis; and no explanation was found in 26% of biopsies. Numerous MA within a biopsy (>9) correlated with CMV infection (P <.005); no other histological features, including size of MA, correlated with the etiology of MA. Overall, 43 of 97 (44%) liver transplantation patients at our institution had biopsies demonstrating MA at some point in their posttransplantation course. CMV infection appears responsible for only a minority of cases. MA, although nonspecific, are an important histological finding in numerous conditions that may have a significant impact on both graft survival and overall patient morbidity.

Abscess↗

PubMed1998

Prescribed versus delivered dialysis in acute renal failure patients.

The current study was designed first to determine separately the prescribed and delivered dose of dialysis and, second, to determine what factors lead to failure to deliver the prescribed dose of dialysis in patients with acute renal failure (ARF). Forty patients, who collectively underwent 136 dialysis treatments, were studied prospectively at two institutions. The results showed that almost half the prescriptions (49%) were for a Kt/V less than 1.2 and, more importantly, nearly 70% of the treatments delivered a Kt/V less than 1.2, the minimally acceptable dose defined in the Dialysis Outcomes Quality Initiative (DOQI) guidelines for chronic hemodialysis (CHD) patients. Patient predialysis weight was the most important variable associated with a low prescribed and delivered dose of dialysis, as well as lack of delivery of the prescribed dose of dialysis. From the statistical model, it is estimated that for every 10-kg increase in predialysis weight, the chance of prescribing or delivering a Kt/V less than 1.2 increased 4.6- and 1.95-fold, respectively. The lower than prescribed blood flow achieved by the temporary catheters and patients not receiving anticoagulation were variables also associated with not receiving the prescribed Kt/V. It is concluded that patients with ARF are prescribed and receive a dose of dialysis that would be considered inadequate for CHD patients. Until the association between dose of dialysis and outcome is better defined, it would be prudent that both the dialysis prescription and the delivery of dialysis to patients with ARF should be performed with the same care and goals as that currently received by patients with end-stage renal disease (ESRD).

Acute Kidney Injury↗

PubMed1998

Change in access blood flow over time predicts vascular access thrombosis.

BACKGROUND: Vascular access thrombosis accounts for at least $1 billion dollars in annual expenses and 25% of hospitalizations for chronic hemodialysis patients. Low vascular access blood flow (less than 800 ml/min) has been shown to modestly increase the relative risk for thrombosis in the subsequent three months. In this study, it is hypothesized that a time-dependent decrease in vascular access blood flow may be more predictive of subsequent thrombosis especially in vascular accesses with flows more than 800 ml/min, since it would indicate the development of a critical outlet stenosis in the graft. METHODS: Ninety-five accesses in 91 CHD patients were prospectively followed over 18 months. Vascular access blood flow was measured every six months by the ultrasound dilution technique. Thrombotic events were recorded during the three study periods. RESULTS: A total of 34 thrombotic events in 95 accesses were documented through the total study duration. Accesses that thrombosed had a 22% decrease in vascular access blood flow during the first observation period and a further 41% decrease during the second observation period as compared to 4% drop and 15% increase during the first and second observation periods, respectively, for accesses that did not thrombose. There was an estimated 13.6-fold (95%, confidence interval 2.68 to 69.16) increase in the relative risk of thrombosis for accesses with more than 35% decrease in vascular access blood flow compared to those accesses with no change in blood flow. There was no statistical difference in the average vascular access blood flow of all patients over the study period. CONCLUSIONS: Accesses that show a large (>15%) decrement in vascular access blood flow are associated with a high risk of thrombosis. Serial measurements of vascular access blood flow predict access thrombosis.

Adult↗

PubMed1998

Casemix adjustment of managed care claims data using the clinical classification for health policy research method.

OBJECTIVES: The objective of this study was to explore the use of the Clinical Classification for Health Policy Research (CCHPR) as a casemix adjustment method for examining physician practice patterns. METHODS: The data source was 2 years of administrative claims from an 86,000 member health maintenance organization in southeastern Michigan. The CCHPR version 2 algorithm, which is in the public domain, was used to assign each claim to one of 260 clinical categories. CCHPR and age-sex categories were used as explanatory variables in multiple linear regression models with approved claims payments in dollars as the outcome variable. Regressions were performed retrospectively for 1994 and 1995, and with 1994 claims' history to predict 1995 utilization. Similar regressions were performed with age-sex categories alone, and also with the ambulatory diagnostic groups. RESULTS: The adjusted R2 value of the retrospective regression models for total approved dollars was 0.42 for both study years when CCHPR categories were used. In contrast, age-sex explanatory variables alone achieved an R2 of 0.02. CONCLUSIONS: The CCHPR method appears to be a promising tool to understand variability in physician resource utilization in managed care.

Adult↗

PubMed1998

Visual assessment of the accuracy of retrospective registration of MR and CT images of the brain.

In a previous study we demonstrated that automatic retrospective registration algorithms can frequently register magnetic resonance (MR) and computed tomography (CT) images of the brain with an accuracy of better than 2 mm, but in that same study we found that such algorithms sometimes fail, leading to errors of 6 mm or more. Before these algorithms can be used routinely in the clinic, methods must be provided for distinguishing between registration solutions that are clinically satisfactory and those that are not. One approach is to rely on a human observer to inspect the registration results and reject images that have been registered with insufficient accuracy. In this paper, we present a methodology for evaluating the efficacy of the visual assessment of registration accuracy. Since the clinical requirements for level of registration accuracy are likely to be application dependent, we have evaluated the accuracy of the observer's estimate relative to six thresholds: 1-6 mm. The performance of the observers was evaluated relative to the registration solution obtained using external fiducial markers that are screwed into the patient's skull and that are visible in both MR and CT images. This fiducial marker system provides the gold standard for our study. Its accuracy is shown to be approximately 0.5 mm. Two experienced, blinded observers viewed five pairs of clinical MR and CT brain images, each of which had each been misregistered with respect to the gold standard solution. Fourteen misregistrations were assessed for each image pair with misregistration errors distributed between 0 and 10 mm with approximate uniformity. For each misregistered image pair each observer estimated the registration error (in millimeters) at each of five locations distributed around the head using each of three assessment methods. These estimated errors were compared with the errors as measured by the gold standard to determine agreement relative to each of the six thresholds, where agreement means that the two errors lie on the same side of the threshold. The effect of error in the gold standard itself is taken into account in the analysis of the assessment methods. The results were analyzed by means of the Kappa statistic, the agreement rate, and the area of receiver-operating-characteristic (ROC) curves. No assessment performed well at 1 mm, but all methods performed well at 2 mm and higher. For these five thresholds, two methods agreed with the standard at least 80% of the time and exhibited mean ROC areas greater than 0.84. One of these same methods exhibited Kappa statistics that indicated good agreement relative to chance (Kappa > 0.6) between the pooled observers and the standard for these same five thresholds. Further analysis demonstrates that the results depend strongly on the choice of the distribution of misregistration errors presented to the observers.

Algorithms↗

PubMed1998

Evaluation of a bioactive glass alloplast in treating periodontal intrabony defects.

This study evaluated the use OF bioactive glass (BG) for repairing/regenerating periodontal intrabony defects. Fourteen systemically healthy patients participated. Each patient had 2 contralateral sites with > or = 6 mm clinical probing depth and radiographic evidence of an intrabony defect. One defect was treated with flap debridement plus BG (test) and the other with flap debridement alone (control). Baseline measurements included gingival index (GI), plaque index (PI), position of the free gingival margin (S/FGM), clinical attachment level (CAL), probing depth (PD), and mobility. At the time of surgery and at surgical reentry (9 to 13 months later), hard tissue measurements included: stent to defect base, bone crest to defect base, and defect width at the bone crest. One-way repeated ANOVA was used to analyze the treatment effect. Friedman's test was used to detect any significant changes of GI, PI and mobility at different time periods (baseline, 3 months, 6 months, and reentry). For multivariate analysis, the random coefficients mixed effect model was applied to adjust the intra-correlation effect. Both treatments resulted in decreased PD and gain of CAL. These changes were only significant (P < 0.05) for the BG treated sites (PD reduction = 1.24+/-0.43 mm, CAL gain = 0.87+/-0.38 mm) from baseline. Defect fill was significant for test (1.1+/-0.4 mm) and control (1.4+/-0.4 mm) alike (P < or = 0.01). Although BG treated sites had more PD reduction and CAL gain than debridement only controls, there were no statistically significant differences between groups for any parameter measured. Further studies are required to clarify the beneficial effects, if any, of BG alloplast in treating periodontal intrabony defects.

Adult↗

PubMed1998

Expression of beta-catenin, alpha-catenin, and E-cadherin in Barrett's esophagus and esophageal adenocarcinomas.

Loss of expression and function of the E-cadherin/catenin membrane complex can result in loss of cell adhesion and contribute to invasive or metastatic potential in carcinomas. The aim of this study was to examine the expression of alpha- and beta-catenin and E-cadherin in Barrett's esophagus with and without dysplasia and in esophageal adenocarcinomas and to identify any relationship with tumor growth pattern and clinical outcome. Immunoperoxidase staining for alpha- and beta-catenin and E-cadherin was performed on specimens of Barrett's esophagus with and without dysplasia and on 54 esophageal adenocarcinoma specimens. Membranous staining for all of the components was seen in normal gastric and esophageal mucosa. Abnormal expression of beta-catenin, alpha-catenin, and E-cadherin was significantly associated with higher degrees of dysplasia in Barrett's esophagus. Fourteen of 16 cases of high grade dysplasia and 7 of 7 cases of intramucosal carcinoma showed abnormal expression of beta-catenin, compared with 3 of 6 cases indefinite for dysplasia and 11 of 17 cases with low grade dysplasia (P = 0.022). Similar results were seen for expression of alpha-catenin (P < .01) and E-cadherin (P = .049). In esophageal adenocarcinomas, preserved expression of these proteins occurred more frequently in well-differentiated tumors; abnormal expression was more common in diffusely infiltrative poorly differentiated tumors that did not form glands. Focal nuclear staining for beta-catenin was present in two high-grade dysplasias, two intramucosal carcinomas, and five adenocarcinomas. No survival advantage was demonstrated for patients whose tumors retained expression of these cell adhesion components. In conclusion, abnormal expression of the E-cadherin/catenin membrane complex is common in esophageal adenocarcinoma and occurs early in the dysplasia/carcinoma sequence in Barrett's esophagus, indicating that disturbances in this cell adhesion complex might be important in tumorigenesis and tumor progression in this disorder.

Adenocarcinoma↗

PubMed1997

Optimal Albunex dosing for enhancement of Doppler tricuspid regurgitation spectra.

Intravenous albunex was more effective than agitated saline in enhancing incomplete Doppler echocardiography spectra for tricuspid regurgitation without a significant alteration in the maximal detected velocity. The optimal dose was 1 to 4 ml in most patients, using an initial dose of 1 ml and titrating further dosing on the basis of the initial contrast effect.

Adult↗

PubMed1997

A pilot study of protracted low dose cisplatin and etoposide with concurrent thoracic radiotherapy in unresectable stage III nonsmall cell lung cancer.

PURPOSE: A Phase II study to evaluate the response rate and toxicity of daily protracted cisplatin and etoposide with concurrent chest irradiation in patients with locally advanced, unresectable nonsmall cell lung cancer (NSCLC). METHODS AND MATERIALS: Twenty-one patients with histologically confirmed locally advanced inoperable NSCLC (Stage IIIA or IIIB) were entered on study. Radiotherapy consisted of 50.4 Gy in 1.8 Gy fractions followed by a 10 Gy boost in 2 Gy fractions. Chemotherapy included the following: Cisplatin was given at 5 mg/m2 i.v. Monday-Friday before RT weeks 1-6. Etoposide was given at 25 mg/m2 i.v. M-F weeks 1, 2, 5, and 6, with 50 mg/m2 p.o. daily on the same weekends. Because of severe myelosuppression in the first two patients, etoposide only was subsequently changed to 20 mg/m2 i.v. M-F weeks 1, 2, 5, and 6. RESULTS: Twenty patients were eligible and evaluable. The overall response rate was 65% (95% confidence interval 41-85%). The median progression-free survival was 43 weeks. The median overall survival was 50.2 weeks with a 1-year survival rate of 45%. Five patients (25%) developed severe radiation pneumonitis, leading to early closure of the study. CONCLUSIONS: Combining daily protracted cisplatin and etoposide with concurrent thoracic irradiation in patients with locally advanced unresectable NSCLC yields a high overall response rate and a median survival that is at least comparable to other combined modality trials. However, future studies using protracted radiosensitizing chemotherapy should be approached cautiously in light of the high incidence of severe radiation pneumonitis encountered in this trial.

Aged↗

PubMed1997

Ambulatory blood pressure monitoring in dialysis patients and estimation of mean interdialytic blood pressure.

To define blood pressure (BP) patterns and control in dialysis patients, 48-hour ambulatory BP monitoring was performed in 36 hemodialysis and 18 peritoneal dialysis patients. Monitoring began during a dialysis session for hemodialysis patients. Data revealed significantly lower diastolic BP (DBP) and lower diastolic load (percentage of diastolic values > 90 mm Hg) in hemodialysis patients compared with peritoneal dialysis patients (80.6 mm Hg v 88.8 mm Hg, respectively, [P < 0.03] and 26% v 45%, respectively [P < 0.03]) for the 48-hour period. When the 2 days were analyzed separately, the difference in diastolic pressures and loads was significant only for the first (dialysis) day. Similarly, trends toward lower systolic BP (SBP) and systolic load in hemodialysis patients existed throughout monitoring and were greater in magnitude during the first day. BP data were fit to a random-coefficient growth curve model to detect periodicity. This sensitive model did not detect diurnal variation of BP in either group. The incidence of hypotension did not differ between the two groups (2.0% v 1.0% of total observations, hemodialysis v peritoneal dialysis). In the hemodialysis group, the proportion of hypotensive observations was significantly greater during the 4 hours postdialysis compared with other periods (5.6% v 1.6%; P < 0.02), a finding that likely reflects the practice of holding antihypertensives until after hemodialysis. However, patient diaries did not reflect hypotensive symptoms during this time. In the hemodialysis group, mean BP and predialysis BP did not correlate with interdialytic sodium load or weight gain. Predialysis and postdialysis BP (recorded by dialysis nurses) correlated significantly with mean BP. Predialysis SBP overestimated mean SBP by an average of 10 mm Hg, while postdialysis SBP underestimated mean SBP by an average of 7 mm Hg. To create formulas to estimate mean SBP and DBP in hemodialysis patients, multiple linear regression was used to model these variables against age, sex, race, and average prehemodialysis/posthemodialysis BP. The model achieved a high degree of fit (r2 = 0.72 for SBP; r2 = 0.65 for DBP), demonstrating that prehemodialysis and posthemodialysis BP can be used to predict mean BP in hemodialysis patients. In summary, our data show the absence of a diurnal variation of BP in dialysis patients and lower BP in hemodialysis patients compared with peritoneal dialysis patients. Among hemodialysis patients, more hypotension occurred after dialysis compared with other periods, and predialysis and postdialysis BP can be used to model mean BP levels.

Analysis of Variance↗

PubMed1997

Predictive measures of vascular access thrombosis: a prospective study.

Malfunction of permanent vascular accesses remains a cause of frequent and costly morbidity in patients receiving chronic hemodialysis (CHD). Several recommendations for routine monitoring of these permanent vascular accesses for incipient failure have been proposed. In this study, multiple indicators of incipient vascular access dysfunction, including "venous" and "arterial" pressures at serial blood flows (200 ml/min, 300 ml/min, and 400 ml/min), percent urea recirculation, Doppler ultrasound, and access blood flow by ultrasound dilution technique were simultaneously evaluated in a total of 220 vascular accesses in 170 chronic hemodialysis patients in two separate study periods (6 months apart). The rate of thrombosis was determined within the subsequent 12 weeks of each study period to assess the short-term predictive power of access thrombosis. During the period of follow-up, there were 34 thrombotic events in 172 polytetrafluoroethylene (PTFE) grafts and only one thrombotic event in 48 arterio-venous fistulas (AVF). Therefore, the statistical analysis was limited to the PTFE grafts. When grafts with thromboses were compared to those without thrombosis by univariate analysis, access blood flow measured either by ultrasound dilution technique (875 +/- 426 ml/min with thrombosis vs. 1193 +/- 677 ml/min without thrombosis, P = 0.001) or by Doppler ultrasound (762 +/- 420 ml/min with thrombosis vs. 1171 +/- 657 ml/min without thrombosis, P = 0.001) were significantly different in the two groups. There was good correlation (r = 0.79, P = 0.0001) between the blood flows determined by both techniques. The grade of stenosis determined by ultrasound was also a statistically significant predictor (P = 0.02). "Venous" and "arterial" pressures were numerically similar and were not statistically different between the accesses that did and those that did not thrombose. When multivariate analysis was used, there was a significantly increased risk of thrombosis only with decreasing access blood flow determined by ultrasound dilution techniques after adjusting for other confounding variables. When the average blood flow of all grafts (1134 ml/min) is considered as the reference access blood flow (relative risk of 1.0), the relative risk of a PTFE thrombotic event within the subsequent 12 weeks was 1.23 at a blood flow 950 ml/min, 1.67 at a blood flow of 650 ml/min and to 2.39 at a blood flow of 300 ml/min. In summary, access blood flow measured by either Dilution or Doppler is a reliable indicator of subsequent short-term thrombosis risk. Other proposed methods of evaluating access dysfunction were not useful in our patients. If simple to use, cost-effective devices to measure dialysis access blood flow become readily available, the measurement of access blood flow will likely become the method of choice for screening of PTFE vascular access dysfunction in hemodialysis patients.

Aged↗

PubMed1997

Antioxidants enhance the cytotoxicity of chemotherapeutic agents in colorectal cancer: a p53-independent induction of p21WAF1/CIP1 via C/EBPbeta.

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States. Five-fluorouracil (5FU) remains the single most effective treatment for advanced disease, despite a response rate of only 20%. Herein, we show that the antioxidants pyrrolidinedithiocarbamate and vitamin E induce apoptosis in CRC cells. This effect is mediated by induction of p21WAF1/CIP1, a powerful inhibitor of the cell cycle, through a mechanism involving C/EBPbeta (a member of the CCAAT/enhancer binding protein family of transcription factors), independent of p53. Antioxidants significantly enhance CRC tumor growth inhibition by cytotoxic chemotherapy in vitro (5FU and doxorubicin) and in vivo (5FU). Thus, chemotherapeutic agents administered in the presence of antioxidants may provide a novel therapy for colorectal cancer.

Acetylcysteine↗

PubMed1997

Genital malformations and coexistent urinary tract or spinal anomalies in patients with imperforate anus.

PURPOSE: Urinary tract malformations have been described in up to 50% of patients with imperforate anus but genital anomalies have been less well analyzed in the same patient population. We sought to evaluate the frequency of coexisting genital, urinary and spinal malformations in a population with imperforate anus. MATERIALS AND METHODS: We reviewed 128 cases of imperforate anus, focusing on genital malformations and their relationship to anomalies of the urinary tract and spine. The series included 69 boys and 59 girls with low (59), intermediate (22) and high (47) imperforate anus. RESULTS: Boys were much more likely to have a genital or upper urinary tract problem than girls (26 or 50 versus 5 or 30%, respectively). The risk for both sets of problems increased with the level of the anorectal lesion. The incidence of genital malformations increased from 14 to 26% in the presence of a renal lesion and from 10 to 23% with an associated spinal problem. Conversely, the incidence of urinary and spinal anomalies increased in patients with genital malformations. CONCLUSIONS: The genitalia of children with imperforate anus should be carefully examined. Patients with anorectal malformations should also be evaluated for urinary tract and spinal problems. The yield of such studies increases in patients with recognized genital malformations.

Abnormalities, Multiple↗

PubMed1997

Paclitaxel/5-fluorouracil/leucovorin in metastatic breast cancer: a Vanderbilt Cancer Center phase II trial.

Fifty-five women with metastatic breast cancer were treated with a regimen consisting of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) 175 mg/m2 administered intravenously over 3 hours on day 1 only plus leucovorin given intravenously over 30 to 60 minutes followed by 5-fluorouracil 350 mg/m2 via intravenous push on days 1 to 3 every 28 days for six cycles. Eight patients were chemotherapy naive. Of 47 previously treated women, 30 had received anthracyclines. Fifty-two patients were evaluable for response. Three (6%) experienced a complete response and 24 (46%) had a partial response, for an overall response rate of 52%. Patients previously exposed to doxorubicin had a response rate similar to those with no prior doxorubicin exposure (50% v 54%, respectively). The median duration of response was 8.6 months and median survival was 17.7 months. Toxicity was modest, with grade 3 or 4 neutropenia observed in only 5.5% (15 of 274) of cycles. Preliminary results indicate that paclitaxel/5-fluorouracillleucovorin is an active, well-tolerated regimen for treating metastatic breast cancer.

Adult↗

PubMed1997

Preliminary analysis of a phase II study of paclitaxel, carboplatin, and hyperfractionated radiation therapy for locally advanced inoperable non-small cell lung cancer.

We conducted a prospective phase II study to determine the response rate, toxicity profile, and survival rate among patients with locally advanced unresectable non-small cell lung cancer receiving concurrent weekly paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), carboplatin, and hyperfractionated radiation therapy followed by two cycles of adjuvant paclitaxel and carboplatin. The weekly paclitaxel/carboplatin regimen was designed to optimize the radiosensitizing properties of paclitaxel during the concurrent phase of treatment. Thirty-two patients with unresectable stage IIIA and IIIB non-small cell lung cancer from Vanderbilt Cancer Center Affiliate Network institutions entered the study from June 1996 until February 1997. Weekly intravenous paclitaxel (50 mg/m2 over 1 hour) and weekly carboplatin (area under the concentration-time curve of 2) plus concurrent hyperfractionated chest radiotherapy (1.2 Gy twice daily [69.6 Gy total]) delivered for 6 weeks were followed by two cycles of paclitaxel (200 mg/m2) and carboplatin (area under the concentration-time curve of 6). Among 22 patients evaluable for response, one (4.5%) achieved a complete response and 16 (72.7%) achieved partial response, for an overall response rate of 77%. Among 23 patients evaluable for toxicity, esophagitis was the principal finding: grade 3 or 4 esophagitis occurred in eight patients (35%). Grade 3 and 4 pulmonary toxicities each occurred in 26% of patients. Thus, weekly paclitaxel/carboplatin plus concurrent hyperfractionated radiotherapy is a well-tolerated outpatient regimen with an encouraging response rate that is at least equivalent to more toxic chemoradiation regimens. These findings indicate that further clinical evaluation of weekly paclitaxel/carboplatin/hyperfractionated radiotherapy is warranted in phase III trials.

Adult↗

PubMed1997

Long-term renal function in heart transplant recipients receiving cyclosporine therapy.

BACKGROUND: Immunosuppression with cyclosporine has improved allograft function and reduced both morbidity and mortality in organ transplantation. However, cyclosporine-induced nephrotoxicity still is a concern. The purpose of our study was to evaluate the effects of cyclosporine on renal function in orthotopic heart transplant recipients. METHODS: Thirty-nine patients who received transplants from 1985 to 1991 and had at least three yearly glomerular filtration rate measurements posttransplantation by 125I-iothalamate clearance method were included in the study. In addition, serum creatinine (before and after transplantation) and cyclosporine doses were analyzed. RESULTS: Maintenance immunosuppression at 1 year consisted of prednisone (0.1 mg/kg/day), azathioprine (2 mg/kg/day), and cyclosporine (12-hour trough level 100 to 150 ng/ml by fluorescence polarization immunoassay). The mean serum creatinine at 1 year was significantly higher than the mean pretransplantation serum creatinine (1.51 +/- 0.32 versus 1.28 +/- 0.38, p < 0.05) and stabilized after the first year. The mean glomerular filtration rate by 125I-iothalamate clearance method was 70.6 +/- 20.3 ml/min/1.73 m2 (range 32 to 105) at 1 year and remained relatively stable during the follow-up period of up to 7 years. Creatinine clearance calculated by the Cockcroft and Gault formula overestimated the true glomerular filtration rate after the third year. The mean cyclosporine dosage was significantly lower after the first-year dose of 3.9 +/- 1.8 mg/kg/day (p < 0.05). Three patients in 39 started hemodialysis at 5, 7, and 10 years after transplantation. CONCLUSION: Our data indicate that the adequacy of renal function is preserved with long-term cyclosporine therapy in heart transplant recipients.

Adolescent↗

PubMed1997

The effect of an absorbable collagen membrane on the subgingival microflora.

The purpose of this study was to determine the effect of use of an absorbable collagen membrane in guided tissue regeneration (GTR) therapy upon the subgingival microflora. The study group consisted of 12 systemically healthy patients with bilateral mandibular furcation defects with attachment loss > or = 6 mm; one site was randomly assigned for GTR treatment while the contralateral site received surgical flap debridement only. Subgingival plaque samples were collected by paper point on the day of surgery and at 2, 4 and 6 months post-surgery. Three sites were sampled in each patient: a collagen membrane site, a control surgical site, and an unoperated control site. Plaque samples were transported in a non-phosphated buffer solution and examined by phase-contrast microscopy. Cocci, rods, spirochetes, fusiforms, curved rods, and total bacteria were recorded per 10 high-power fields. Following statistical analysis utilizing the Bonferroni (Dunn) t test, no differences in total bacterial counts were found among the sites at any of the time intervals examined. Total bacterial counts were found lower at both the collagen membrane and control surgical sites post-surgery as compared to unoperated control sites, but these differences were not statistically significant (P > .05). In addition, no significant differences were detected in bacterial profiles between sites or individual time points. Results from this 6-month limited clinical trial suggest that the placement of an absorbable collagen membrane as part of a standard surgical regimen for GTR therapy does not alter the local microflora.

Absorption↗

PubMed1996

Hemodynamic exercise testing. A valuable tool in the selection of cardiac transplantation candidates.

BACKGROUND: Peak exercise oxygen consumption (Vo2), a noninvasive index of peak exercise cardiac output (CO), is widely used to select candidates for heart transplantation. However, peak exercise Vo2 can be influenced by noncardiac factors such as deconditioning, motivation, or body composition and may yield misleading prognostic information. Direct measurement of the CO response to exercise may avoid this problem and more accurately predict prognosis. METHODS AND RESULTS: Hemodynamic and ventilatory responses to maximal treadmill exercise were measured in 185 ambulatory patients with chronic heart failure who had been referred for cardiac transplantation (mean left ventricular ejection fraction, 22 +/- 7%; mean peak Vo2, 12.9 +/- 3.0 mL. min-1.kg-1). CO response to exercise was normal in 83 patients and reduced in 102. By univariate analysis, patients with normal CO responses had a better 1-year survival rate (95%) than did those with reduced CO responses (72%) (P < .0001). Survival in patients with peak Vo2 of > 14 mL.min-1.kg-1 (88%) was not different from that of patients with peak Vo2 of < or = 14 mL.min-1.kg-1 (79%) (P = NS). However, survival was worse in patients with peak Vo2 of < or = 10 mL.min-1.kg-1 (52%) versus those with peak Vo2 of > 10 mL.min-1.kg-1 (89%) (P < .0001). By Cox regression analysis, exercise CO response was the strongest independent predictor of survival (risk ratio, 4.3), with peak Vo2 dichotomized at 10 mL. min-1.kg-1 (risk ratio, 3.3) as the only other independent predictor. Patients with reduced CO responses and peak Vo2 of < or = 10 mL.min-1.kg-1 had an extremely poor 1-year survival rate (38%). CONCLUSIONS: Both CO response to exercise and peak exercise Vo2 provide valuable independent prognostic information in ambulatory patients with heart failure. These variables should be used in combination to select potential heart transplantation candidates.

Analysis of Variance↗