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Biomedical subjects

M Lieber

Publications and source records attributed to M Lieber.

At least 19 recordsLinked to original sources
PubMed1999

Serum prostate-specific antigen concentration is a powerful predictor of acute urinary retention and need for surgery in men with clinical benign prostatic hyperplasia. PLESS Study Group.

OBJECTIVES: Prostate-specific antigen (PSA) is produced exclusively in the prostate gland and is currently the most useful clinical marker for the detection of prostate cancer. In this report, we examine whether serum PSA is also a predictor of important benign prostatic hyperplasia (BPH)-related outcomes, acute urinary retention (AUR), and the need for BPH-related surgery. METHODS: Three thousand forty men were treated with either placebo or finasteride in a double-blind, randomized study of 4-year duration. Serum PSA was measured at baseline, and baseline prostate volume was measured in a 10% subset of 312 men. Probabilities and cumulative incidences of AUR and BPH-related surgery, as well as reduction in risk of events with finasteride, were calculated for the entire patient population, stratified by treatment assignment, baseline serum PSA, and prostate volume. RESULTS: The risk of either needing BPH-related surgery or developing AUR ranged from 8.9% to 22.0% during the 4 years in placebo-treated patients stratified by increasing prostate volume and from 7.8% to 19.9% when stratified by increasing serum PSA. In comparison with symptom scores, flow rates, and residual urine volume, receiver operating characteristic curve analyses showed that serum PSA and prostate volume were the most powerful predictors of spontaneous AUR in placebo-treated patients (area under the curve 0.70 and 0.81, respectively). Finasteride treatment reduced the relative risk of needing surgery or developing AUR by 50% to 74% and by 43% to 60% when stratified by increasing prostate volume and serum PSA, respectively. CONCLUSIONS: Serum PSA and prostate volume are powerful predictors of the risk of AUR and the need for BPH-related surgery in men with BPH. Knowledge of baseline serum PSA and/or prostate volume are useful tools to aid physicians and decision makers in predicting the risk of BPH-related outcomes and choosing therapy for BPH.

Acute Disease↗
PubMed1999

Selenium-based digital radiography versus conventional film-screen radiography of the hands and feet: a subjective comparison.

OBJECTIVE: The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography. SUBJECTS AND METHODS: Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark. RESULTS: In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images. CONCLUSION: Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Aged↗
PubMed1999

Comparison of two barium suspensions for dedicated small-bowel series.

OBJECTIVE: The in vivo radiographic features of two commercially available formulations of barium used as contrast media in dedicated small-bowel series were compared. SUBJECTS AND METHODS: Fifty-six consecutive outpatients referred for a dedicated small-bowel series were randomly administered either E-Z-Paque or Entrobar. Representative survey radiographs from each examination were randomized and reviewed by six gastrointestinal radiologists from three institutions. Each observer assigned a numeric score (1 = poor, 2 = fair, 3 = good, and 4 = excellent) that rated the quality of the radiograph with respect to these characteristics: definition of fold pattern, translucency, distention, and integrity of the barium column. Statistical analysis was performed for each characteristic using Wilcoxon's two-sample rank sum test. RESULTS: All six observers found a statistically significant difference between the two barium formulations for mean scores for definition of fold pattern and translucency. Mean scores for fold pattern were 3.3, 3.0, 3.2, 3.6, 3.3, and 3.4 for Entrobar and 2.1, 2.3, 2.4, 3.2, 2.6, and 2.7 for E-Z-Paque. Mean scores for translucency were 2.5, 2.7, 2.8, 3.1, 2.7, and 3.3 for Entrobar and 1.6, 1.7, 2.1, 2.3, 1.9, and 2.7 for E-Z-Paque. No statistically significant difference was found for mean score for distention or integrity of the barium column. CONCLUSION: On radiographs, Entrobar was found to have superior characteristics for visualization of fold pattern and translucency but offered no advantages for distention or integrity of the barium column. Improved translucency and definition of fold pattern may translate into improved sensitivity and confidence in diagnosing small-bowel abnormality.

Barium Sulfate↗
PubMed1998

The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia. Finasteride Long-Term Efficacy and Safety Study Group.

BACKGROUND: Finasteride is known to improve urinary symptoms in men with benign prostatic hyperplasia, but the extent to which the benefit is sustained and whether finasteride reduces the incidence of related events, including the need for surgery and the development of acute urinary retention, is not known. METHODS: In this double-blind, randomized, placebo-controlled trial, we studied 3040 men with moderate-to-severe urinary symptoms and enlarged prostate glands who were treated daily with 5 mg of finasteride or placebo for four years. Symptom scores (on a scale of 1 to 34), urinary flow rates, and the occurrence of outcome events were assessed every four months in 3016 men. Prostate volume was measured in a subgroup of the men. Complete data on outcomes were available for 2760 men. RESULTS: During the four-year study period, 152 of the 1503 men in the placebo group (10 percent) and 69 of the 1513 men in the finasteride group (5 percent) underwent surgery for benign prostatic hyperplasia (reduction in risk with finasteride, 55 percent; 95 percent confidence interval, 41 to 65 percent). Acute urinary retention developed in 99 men (7 percent) in the placebo group and 42 men (3 percent) in the finasteride group (reduction in risk with finasteride, 57 percent; 95 percent confidence interval, 40 to 69 percent). Among the men who completed the study, the mean decreases in the symptom score were 3.3 in the finasteride group and 1.3 in the placebo group (P<0.001). Treatment with finasteride also significantly improved urinary flow rates and reduced prostate volume (P<0.001). CONCLUSIONS: Among men with symptoms of urinary obstruction and prostatic enlargement, treatment with finasteride for four years reduces symptoms and prostate volume, increases the urinary flow rate, and reduces the risk of surgery and acute urinary retention.

5-alpha Reductase Inhibitors↗
PubMed1998

Parathyroid detection in secondary hyperparathyroidism with 123I/99mTc-sestamibi subtraction single photon emission computed tomography.

123I/99mTc-sestamibi subtraction single photon emission computed tomography (SPECT) has been proposed to detect hyperplastic parathyroid tissue, but the clinical usefulness of this technique in secondary hyperparathyroidism is uncertain. The purpose of this study was to evaluate preoperative parathyroid localization using 123I/99mTc-sestamibi subtraction SPECT in patients with renal failure and secondary hyperparathyroidism. Nineteen patients with chronic renal failure and secondary hyperparathyroidism underwent 123I/99mTc-sestamibi subtraction SPECT imaging preoperatively. None of these patients had undergone previous neck surgery. The location, weight, and histopathological results of all identified parathyroid glands were recorded. Surgery was considered successful in all patients, with resection of a total of 74 hyperplastic parathyroid glands. 123I/99mTc-sestamibi subtraction SPECT correctly identified 57 of these parathyroid glands (77% sensitivity). The mean weight among the true positive glands (n = 57) was 1031 mg (range, 45-7900 mg), and that among the false negative glands (n = 17) was 465 mg (range, 20-1800 mg). This difference between the mean weights was statistically significant (P = 0.018). There was a positive correlation between parathyroid weight and detectability with 123I/99mTc-sestamibi subtraction SPECT (Spearman correlation = 0.28; P = 0.0167). 123I/99mTc-sestamibi subtraction SPECT is able to correctly localize hyperplastic parathyroid glands in patients with renal failure and secondary hyperparathyroidism, but there is a fairly weak relationship between preoperative detection rate and anatomical parathyroid gland size.

Adenoma↗
PubMed1998

Prognostic significance of allelic imbalance of chromosome arms 7q, 8p, 16q, and 18q in stage T3N0M0 prostate cancer.

Frequent allelic imbalance of polymorphic markers mapped to regions of the 7q, 8p, 16q, and 18q arms has been reported in prostate cancer. To better define the clinical significance of these genetic alterations, we undertook a retrospective analysis of systemic progression and survival in patients with a single stage of prostate cancer. We ascertained all 227 patients from the Mayo Clinic Radical Prostatectomy Registry who had a histologic high-grade, pathologic stage C (pT3N0M0) tumor surgically removed between 1966 and 1987. The mean follow-up of this population of patients was 7.7 years. DNAs were extracted from cancer lesions identified in 5-micron paraffin-embedded tumor sections. Control DNAs were obtained from surgically removed lymph nodes. Paired DNA samples of 153 patients were available for analysis using 16 polymorphic microsatellite markers mapped to 7q31, 8p22-p21, 16q23-qter, and 18q21-q22. The frequencies of allelic imbalance for at least one marker mapped to 7q31, 8p22-p21, 16q23-qter, and 18q21-q22 were 30, 58, 53, and 45% of all informative cases, respectively. Allelic imbalance at 7q31 strongly correlated with systemic cancer progression and to a slightly lesser extent with cancer-specific death. Eight-year systemic cancer progression-free rates were 58 and 81% for cases with and without 7q31 allelic imbalance, respectively (P < 0.001). Eight-year prostate cancer-specific survival rates were 70 and 85% with and without 7q31 allelic imbalance, respectively (P = 0.019). Multivariate analysis indicated that allelic imbalance at 7q31 is a significant independent predictor of systemic progression (P < 0.001) and possibly prostate cancer death (P = 0.029). In addition, allelic imbalance of the specific loci D7S522 (7q31.1) and D8S258 (8p22-p21.3) was strongly associated with systemic progression (P < 0.001 and P = 0.010, respectively) and with prostate cancer death (P < 0.001 and P = 0.009, respectively). The results suggest that a gene or genes mapped to 7q31.1 and possibly 8p22-p21.3 play an important role in tumor progression, and that allelic imbalances at these regions are markers for poor prognosis in prostate carcinoma.

Aged↗
PubMed1997

Segmented three-dimensional echo-planar flow imaging of the cervical carotid arteries.

PURPOSE: To implement and assess the application of segmented three-dimensional echo-planar MR imaging time-of-flight flow sequences for studying the anatomy of the cervical carotid arteries at 1.5 T. METHODS: The 3-D echo-planar sequences were segmented along the in-plane phase-encoding direction. Echo train lengths (ETLs) of 3 and 5 and signal bandwidths of +/-25, +/-33, and +/-50 KHz were tested along with a conventional (ETL = 1) 3-D MR flow study in six healthy volunteers and in five patients with known arteriosclerotic disease involving the carotid bifurcation as confirmed by conventional angiography. The volunteer data were used to rank the techniques with respect to vessel dimension, vessel/background contrast, and quality by four trained neuroradiologists. For the patient studies, the percentage of stenoses was measured for all MR studies and compared against the conventional angiographic data using the criteria of the North American Symptomatic Carotid Endarterectomy Trial. RESULTS: Using Wilcoxon's test statistic and a significance level of .05, we found that the conventional MR flow examination was better than the segmented techniques and that the segmented techniques with ETL of 3 were superior to their counterparts with ETL of 5. For the ETL of 3 techniques, the high-bandwidth studies were inferior to their lower bandwidth counterparts; however, there was no significant difference between the performance of the medium- and low-bandwidth sequences. The patient data revealed that the segmented techniques consistently overestimated the severity of stenosis; however, in no instance did any of the segmented examinations erroneously indicate the presence of disease. CONCLUSIONS: The reduction in acquisition time and the zero false-positive rate we obtained suggest that segmented 3-D echo-planar MR flow techniques may be used as a screening/locating study for cervical carotid artery disease.

Adult↗
PubMed1996

Immunoglobulin diversity: rearranging by cutting and repairing.

The recombination process that assembles antigen-receptor genes is now understood in some biochemical detail. The initial steps reflect a common theme seen in retroviral integration and prokaryotic transposition, and the later steps involve the enzymatic machinery for double-strand break DNA repair.

Animals↗
PubMed1996

Hyperbaric oxygen therapy for nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To evaluate the effectiveness of hyperbaric oxygen therapy in reducing optic nerve damage in acute nonarteritic anterior ischemic optic neuropathy. METHODS: Twenty-two eyes in 20 patients with acute nonarteritic anterior ischemic optic neuropathy were treated with hyperbaric oxygen (100% oxygen, 2.0 absolute atmospheres of pressure) in two 90-minute inhalation sessions per day for ten days. Changes in mean visual acuity and mean sensitivity loss were compared with those of 27 untreated control patients with acute nonarteritic anterior ischemic optic neuropathy, and proportions of patients with a change in acuity or mean sensitivity loss were compared with controls. Similar analysis was performed on subgroups based on time delay from symptom onset to therapy. RESULTS: Mean values for visual acuity were increased at final examination in both groups; although the increase was greater in controls, the difference was not statistically significant. Mean visual field sensitivity loss was minimally increased; although the increase was smaller in controls, the difference between groups was not significant. There was no significant difference between groups in proportions of patients with change in acuity score or mean sensitivity loss. Stratification by time delay to therapy did not suggest that treatment within nine days produced better visual results than that for either controls or those treated later. CONCLUSIONS: Hyperbaric oxygen therapy using 100% oxygen and 2.0 absolute atmospheres of pressure did not produce a significant improvement in visual acuity or visual field for patients with acute nonarteritic anterior ischemic optic neuropathy.

Acute Disease↗
PubMed1995

Treatment with finasteride following radical prostatectomy for prostate cancer.

OBJECTIVES: The objective of this study was to evaluate the effect of finasteride (10 mg/d) or placebo on serum prostate-specific antigen (PSA) and recurrence rates in men with detectable PSA levels after radical prostatectomy. METHODS: A total of 120 men, 48 to 89 years old, previously treated with radical prostatectomy for prostate cancer within the past 10 years, with serum PSA levels between 0.6 and 10.0 ng/mL, with no evidence of skeletal metastasis on bone scan, and with no previous androgen deprivation therapy, were treated with 10 mg finasteride or placebo in a double-blind fashion for 12 months. After the first year, all patients were treated with finasteride for an additional 12 months. Primary endpoints were serum PSA levels and recurrence rates defined as positive bone scan or positive biopsy. RESULTS: Patients treated with finasteride had a delayed increase in serum PSA compared with placebo of approximately 9 months in the first year and 14 months by the end of the second year. Patients with baseline PSA levels less then 1.0 ng/mL had no significant increase in serum PSA during the 2 years of treatment. Fewer recurrences were observed in the finasteride group, but these differences were not statistically significant. Finasteride was well tolerated, and side effects were balanced between treatment groups. CONCLUSIONS: The results of this study indicate that treatment with finasteride delays but does not prevent the rise in serum PSA observed in untreated patients with detectable PSA levels after radical prostatectomy. The reduction in local and distant recurrences in the finasteride group suggests that the effect on PSA reflects a direct effect on tumor growth without affecting the initial response to subsequent hormonal therapy. These data require confirmation by studies that are longer and larger, focused on demonstrating significant differences in progression rates and survival before the use of finasteride can be considered as an option for men with detectable PSA levels after radical prostatectomy.

Aged↗
PubMed1994

Clinical utility of cellular DNA measurements in prostate carcinoma. Consensus Conference on Diagnosis and Prognostic Parameters in Localized Prostate Cancer. Stockholm, Sweden, May 12-13, 1993.

At a WHO consensus conference on Early Diagnosis and Prognostic Parameters in Localized Prostate Cancer, a working group discussed the clinical utility of DNA measurements in stages T2 and T3 prostate carcinoma. Incidentally discovered prostate cancer of stage T1 was excluded. The members of the working group, representing various clinical and laboratory disciplines, discussed technical considerations of DNA measurements by flow and image analysis, pretreatment prediction of prognosis, and posttreatment clinical relevance. The group agreed to subdivide tumors into diploid, tetraploid and non-tetraploid aneuploid, expressing various degrees of aggressiveness and gave guidance for the definition of limits of these groups. The panel agreed that knowledge on DNA ploidy prior to treatment is of value in treatment decisions, particularly when surveillance is a treatment option. Aneuploid tumors can be expected to respond very poorly to either irradiation or endocrine therapy, and the presence of aneuploid tumor, either on pretreatment biopsies or in radical prostatectomy specimens, is an ominous sign. The identification of a group of patients with a uniformly poor prognosis should encourage medical oncologists and basic scientists to develop adequate treatment options for this particular group. The panel expressed a strong opinion that DNA ploidy should be uniformly studied in clinical trials, particularly in patients with localized prostate cancer.

Biopsy↗
PubMed1991

Incidence and outcome of surgery for benign prostatic hyperplasia among residents of Rochester, Minnesota: 1980-87. A population-based study.

The incidence and outcome of surgery for benign prostatic hyperplasia (BPH) was studied in Rochester, Minnesota, during the period 1980-1987. Three hundred thirty Rochester men without a diagnosis of prostate or bladder cancer underwent prostatectomy for BPH for the first time. Mean and median ages were both seventy (range: 46-95). The incidence of initial prostatectomy for BPH among men forty-five years of age and older age-adjusted to the 1980 U.S. white male population was 642 cases per 100,000 persons per year (py). Among the 330 men undergoing initial prostatectomy for BPH, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within thirty days of surgery, and 13 (3.9%) had other serious complications within thirty days after surgery, including 1 death (surgical mortality 0.3%). Forty-five patients (14%) required blood transfusions within thirty days of surgery. The likelihood of reoperation within six years of the initial surgery was 15.1 percent (95% CI 9.7, 20.6). Short- and long-term postoperative mortality was not statistically significantly different than expected based on age- and sex-specific mortality statistics for Rochester, Minnesota.

Aged↗
PubMed1991

Benign prostatic hyperplasia: a population-based study.

To evaluate the incidence and outcome of initial surgery for benign prostatic hyperplasia (BPH) and to clarify the natural occurrence and progression of such urologic diseases, two studies have been conducted in a free-living population in Rochester, MN. The first followed 330 men who had not been diagnosed with prostate or bladder cancer at the time of prostatectomy. All surgery subjects were area residents and between 46 and 95 years of age (mean age 70 years). Among the operated subjects, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within 30 days after surgery, and 13 (3.9%) experienced other serious complications in that same time period. Blood transfusions within 30 days of surgery were necessary in 45 patients (14%). The risk of reoperation within 6 years of the initial surgery was calculated at 15.1% (95% CI: 9.7, 20.6). On the basis of age- and sex-specific mortality statistics for Rochester, short- and long-term postoperative mortality was not statistically significantly different from that expected. Results of the second study are not yet available. This population-based evaluation of the natural history of urologic disease is expected to clarify the relative utility of various treatment options and provide a useful perspective on the management of BPH.

Aged↗
PubMed1990

Mutagenesis as viewed from another perspective.

Mutation has generally been considered a random process, not directed. Thus, a mechanism allowing for adaptively responsive mutagenesis has conceptually been precluded. However, an adaptively directed mutagenesis in response to environmental stress can be based upon genetic mutator systems. Such systems, known for years, have been seen as exceptional and not considered in terms of an adaptively responsive mutagenesis. Environmental stress which invokes this type of mutagenesis can thus be regarded as mutagenic itself, and our concept of what is mutagenic must therefore be broadened. Relevant matters are also discussed.

Adaptation, Physiological↗