Biomedical subjects

D S Smith

Publications and source records attributed to D S Smith.

At least 73 records · Page 4Linked to original sources

PubMed1997

The early detection of prostate carcinoma with prostate specific antigen: the Washington University experience.

BACKGROUND: It is not yet known whether screening for the detection of early prostate carcinoma will reduce mortality rates. However, data are available to assess intermediate outcomes from screening, including the performance characteristics of the screening tests and shifts in disease stage. METHODS: Approximately 30,000 community volunteers (mean age 60 years; <5% nonwhite) were enrolled in 1 of 3 screening studies. Volunteers were screened with PSA or PSA in combination with digital rectal examination at 6-month intervals, and prostatic biopsy was recommended for those with results suspicious for cancer. Based on a first-time screen, the current study reports screening test results, the proportion of men recommended to undergo biopsy, the proportion who actually underwent biopsy, and the carcinoma detection rates for each study, stratified by initial PSA level. The authors also report the pathologic features of screen-detected carcinomas for a subset of men who underwent radical prostatectomy and for whom complete embedding and microscopic examination of the surgical specimen was performed. RESULTS: Approximately 10% of the volunteers had PSA levels >4.0 ng/mL and 3-10% had digital rectal examination results suspicious for cancer. Overall, 9-20% of volunteers were recommended to undergo biopsy and 8-13% actually underwent the procedure. The positive predictive value for carcinoma detection ranged from 25-33% across studies. In the subset of men for whom surgical specimens were completely embedded, the majority of tumors detected had the clinicopathologic features of significant carcinoma (<10% possibly harmless). CONCLUSIONS: The intermediate outcomes for screening with PSA and/or PSA in combination with digital rectal examination are encouraging. In community volunteers these screening tests demonstrated reasonable positive predictive value and detected carcinomas at an earlier stage. The majority of screen-detected tumors had the pathologic characteristics of medically significant carcinoma.

Biopsy↗

PubMed1997

Prostate cancer detection in men with serum PSA concentrations of 2.6 to 4.0 ng/mL and benign prostate examination. Enhancement of specificity with free PSA measurements.

OBJECTIVE: To determine the detection rate of prostate cancer in a screening population of men with prostate-specific antigen (PSA) concentrations of 2.6 to 4.0 ng/mL and a benign prostate examination, to assess the clinicopathological features of the cancers detected, and to assess the usefulness of measuring the ratio of free to total PSA to reduce the number of prostatic biopsies. DESIGN: A community-based study of serial screening for prostate cancer with serum PSA measurements and prostate examinations. SETTING: University medical center. SUBJECTS: A total of 914 consecutive screening volunteers aged 50 years or older with serum PSA levels of 2.6 to 4.0 ng/mL who had a benign prostate examination and no prior screening tests suspicious for prostate cancer, 332 (36%) of whom underwent biopsy of the prostate. MAIN OUTCOME MEASURES: Cancer detection rate, clinical and pathological features of cancers detected, and specificity for cancer detection using measurements of percentage of free PSA. RESULTS: Cancer was detected in 22% (73/332) of men who underwent biopsy. All cancers detected were clinically localized, and 81% (42/52) that were surgically staged were pathologically organ confined. Ten percent of the cancers were clinically low-volume and low-grade tumors, and 17% of those surgically staged were low-volume and low-grade or moderately low-grade tumors (possibly harmless). Using a percentage of free PSA cutoff of 27% or less as a criterion for performing prostatic biopsy would have detected 90% of cancers, avoided 18% of benign biopsies, and yielded a positive predictive value of 24% in men who underwent biopsy. CONCLUSIONS: There is an appreciable rate of detectable prostate cancer in men with serum PSA levels of 2.6 to 4.0 ng/mL. The great majority of cancers detected have the features of medically important tumors. Free serum PSA measurements may reduce the number of additional biopsies required by the lower PSA cutoff.

Aged↗

PubMed1997

A transcription-dependent switch controls competence of adult neurons for distinct modes of axon growth.

Although maturing neurons undergo a precipitous decline in the expression of genes associated with developmental axon growth, structural changes in axon arbors occur in the adult nervous system under both normal and pathological conditions. Furthermore, some neurons support extensive regrowth of long axons after nerve injury. Analysis of adult dorsal root ganglion (DRG) neurons in culture now shows that competence for distinct types of axon growth depends on different patterns of gene expression. In the absence of ongoing transcription, newly isolated neurons can extend compact, highly branched arbors during the first day in culture. Neurons subjected to peripheral axon injury 2-7 d before plating support a distinct mode of growth characterized by rapid extension of long, sparsely branched axons. A transition from "arborizing" to "elongating" growth occurs in naive adult neurons after approximately 24 hr in culture but requires a discrete period of new transcription after removal of the ganglia from the intact animal. Thus, peripheral axotomy-by nerve crush or during removal of DRGs--induces a transcription-dependent change that alters the type of axon growth that can be executed by these adult neurons. This transition appears to be triggered, in large part, by interruption of retrogradely transported signals, because blocking axonal transport in vivo can elicit competence for elongating growth in many DRG neurons. In contrast to peripheral axotomy, interruption of the centrally projecting axons of DRG neurons in vivo leads to subsequent growth in vitro that is intermediate between "arborizing" and "elongating" growth. This suggests that the transition between these two modes of growth is a multistep process and that individual steps may be regulated separately. These observations together suggest that structural remodeling in the adult nervous system need not involve the same molecular apparatus as long axon growth during development and regeneration.

Afferent Pathways↗

PubMed1997

Is unilateral spatial neglect a single phenomenon? A comparative study between exploratory-motor and visual-counting tests.

The aim of this study is to report the preliminary findings of a traditional battery of tests and our original battery capable of assessing the presence of components and extent of lesions in patients with unilateral spatial neglect. Thirty patients who had unilateral spatial neglect with a stroke in the right hemisphere were assessed for unilateral spatial neglect on exploratory-motor (E-M) tasks, visual-counting (V-C) tasks, and traditional neglect batteries at least 4 weeks after the onset. Other neuropsychological tests and computed tomography were also performed to investigate the relationship with neglect. A factor analysis showed that our tasks loaded significantly on three factors. E-M neglect was found in 16 patients, and V-C neglect in 22 patients with unilateral spatial neglect. There were high correlations between E-M neglect and motor paralysis, word fluency, backward digit span and motor impersistence. There were high correlations between V-C neglect and visual-field defect, line bisection, line cancellation and figure copying. Lesions in the frontal lobe, caudate, insula, and anterior portion of the paraventricular white matter were commonly associated with E-M neglect. Lesions in the occipital lobe were also associated with V-C neglect. We suggest that unilateral neglect is not a single phenomenon, but rather involves several different components. We propose that E-M and V-C tasks are useful methods for evaluating the extent of lesions in patients with unilateral spatial neglect.

Adult↗

PubMed1997

Urinary interleukin-8/creatinine level as a predictor of response to intravesical bacillus Calmette-Guerin therapy in bladder tumor patients.

PURPOSE: Our purpose was to determine whether urinary interleukin-8 (IL-8) levels could be used to predict a tumor-free response to intravesical bacillus Calmette-Guerin (BCG) therapy in bladder cancer patients. MATERIALS AND METHODS: A total of 46 patients with superficial bladder cancer underwent an initial 6-week course of intravesical BCG therapy after transurethral resection. Voided urine samples were collected immediately before BCG instillations 1 and 6. Urine samples were centrifuged at 1,500 rpm for 8 minutes, and the supernatant was stored at -20 C. An enzyme-linked immunosorbent assay technique was used to measure urinary IL-8 levels. The Jaffé method was used to measure urinary creatinine. Results were expressed as the IL-8/creatinine ratio. Patients were followed with cystoscopy and urinary cytology every 3 months to detect bladder tumor recurrence. RESULTS: IL-8/creatinine ratios were measured in 31 patients before BCG therapy and were undetectable in 15. After 5 weeks of intravesical BCG therapy, IL-8/creatinine ratios fell in 27 patients (59%), were unchanged in 10 (22%) and rose in 9 (19%). Mean followup was 20.9 months (range 3 to 48). There was no association between the direction of change in IL-8/creatinine ratio and response to intravesical BCG therapy (p = 0.5). CONCLUSIONS: Urinary IL-8 levels obtained before intravesical BCG therapy and after instillation 5 of BCG were not helpful in predicting tumor recurrences in bladder cancer patients.

Adjuvants, Immunologic↗

PubMed1997

Racial differences in operating characteristics of prostate cancer screening tests.

PURPOSE: We evaluated racial differences in the operating characteristics of prostate specific antigen (PSA) and digital rectal examination as screening tests for early detection of prostate cancer. MATERIALS AND METHODS: We screened 18,527 white and 949 black men 50 years old or older using serum PSA measurement and digital rectal examination. We recommended biopsies if either test was suspicious for cancer. For PSA greater than 4.0 ng./ml. and rectal examination we calculated relative sensitivity (percentage of men with cancer who had a positive test), specificity (percentage of men without cancer who had a negative test) and positive predictive value (percentage of men with a positive test in whom cancer was detected) for the prediction of prostate cancer stratified by race. RESULTS: In white and black men PSA greater than 4.0 ng./ml. detected more cancers than rectal examination (p < 0.002) with a trend for a greater increase in sensitivity in black men. PSA was associated with fewer false-positives than rectal examination in white (p < 0.0001) but not in black (p > 0.05) men. Positive predictive value for prostate cancer of PSA and rectal examination was greater in black than in white men (48 versus 34 and 38 versus 22%, respectively). CONCLUSIONS: PSA detects more cancers than rectal examination in both races, although this advantage is more pronounced in black men. In white men PSA yielded fewer false-positive results than rectal examination. However, PSA had more false-positive results than rectal examination in black men. Cancer was detected in a higher percentage of black men with PSA greater than 4.0 ng./ml. and, therefore, the risk of cancer associated with PSA greater than 4.0 ng./ml. differs by race. In a screening setting the widely accepted 25 to 30% positive predictive value for PSA greater than 4.0 ng./ml. may only apply to white men. A higher risk estimate of 36 to 60% is more accurate in black men.

Black People↗

PubMed1997

Serum free prostate specific antigen and prostate specific antigen density measurements for predicting cancer in men with prior negative prostatic biopsies.

PURPOSE: We examined the usefulness of measurements of free prostate specific antigen (PSA) and PSA density for predicting prostate cancer in men who had had a prior negative biopsy, a serum PSA level of 4.1 to 10.0 ng./ml. and benign findings on prostate examination. MATERIALS AND METHODS: We measured percent free serum PSA and PSA density in 163 male volunteers age 50 years or older who were advised to have repeat prostatic biopsies for a serum PSA level of 4.1 to 10.0 ng./ml. RESULTS: Of 99 men who had repeat biopsies 20 (20%) had prostate cancer detected. Prostate cancer was significantly associated with lower free PSA level and higher PSA density, with overlap in 83% of the cases. The use of percent free PSA cutoffs of 28 and 30% would have detected 90 and 95% of cancers, respectively, and avoided 13 and 12% of the biopsies, respectively. PSA density cutoffs of 0.10 and 0.08 would have detected 90 and 95% of cancers, respectively, and avoided 31 and 12% of biopsies, respectively. CONCLUSIONS: Free PSA and PSA density predict prostate cancer in men who have had prior negative prostatic biopsies, serum PSA levels of 4.1 to 10.0 ng./ml. and a benign prostate examination. Both parameters may be used to avoid unnecessary biopsies with an acceptable decrease in sensitivity. Further studies are needed to determine cutoffs to be used in clinical practice.

Aged↗

PubMed1997

Stability of serum total and free prostate specific antigen under varying storage intervals and temperatures.

PURPOSE: Measurement of total serum prostate specific antigen (PSA) is widely used as an aid to early detection of prostate cancer. Measurement of the ratio of free-to-total PSA (percentage of free PSA) may help increase specificity of PSA testing. We prospectively studied the effects of varying the storage temperature and interval on total and free PSA levels. MATERIALS AND METHODS: We measured the baseline total and free serum PSA levels in 36 volunteers (mean age 66 years) and then retested aliquots of these serum samples after varying storage intervals (24 hours, 2 weeks and 9 months) at 3 different temperatures (4C, -20C and -70C). Volunteers represented a spectrum of prostatic conditions (PSA levels 2.0 to 4.0 ng./ml., PSA levels greater than 4.0 ng./ml. without cancer and PSA levels greater than 2.0 ng./ml. with prostate cancer). We used repeated measures analysis of variance to test for changes in total and free PSA levels as a function of time and temperature. We also evaluated the impact of storage at different temperatures and times on the percentage of free PSA. RESULTS: Across groups total and free serum PSA decreased from the baseline level differentially as a function of longer storage interval and higher temperature (p <0.05). No significant difference was found for change in total PSA at 24 hours, 2 weeks or 9 months for storage temperatures of -20C compared with -70C. A significant change from baseline level was found for free PSA when stored in -20C compared with -70C for 2 weeks but the magnitude of the change was modest. CONCLUSIONS: For storage intervals up to 9 months total PSA is more stable than free PSA under temperature conditions ranging from 4C to -70C. This differential stability has important implications for the clinical evaluation of percentage of free PSA to distinguish between benign and malignant diseases of the prostate.

Clinical Protocols↗

PubMed1997

Effect of ejaculation on serum total and free prostate-specific antigen concentrations.

OBJECTIVES: Measurement of total serum prostate-specific antigen (PSA) is widely used as an aid to early detection of prostate cancer. Measurement of the ratio of free to total PSA may increase the specificity of PSA testing. To improve specificity further, other factors that may cause transient increases in PSA, such as ejaculation, have been identified. We prospectively studied the effect of ejaculation on total and free PSA levels and examined whether changes induced by ejaculation would affect recommendations for performing prostatic biopsy. METHODS: We measured the baseline total and free serum PSA levels and obtained measurements 1.6, and 24 hours after ejaculation in 20 volunteers (mean age 59 years). All men had baseline PSA levels less than 4.0 ng/mL. We used repeated-measures analysis of variance to test for changes in total, free, and percent free PSA after ejaculation. We also calculated the proportion of men with PSA levels greater than the expected biologic variability at each timepoint. RESULTS: The mean total, free, and percent free serum PSA increased 1 hour after ejaculation. Mean total PSA levels remained significantly increased 6 and 24 hours after ejaculation. Mean free PSA decreased to baseline levels by 6 hours after ejaculation, and percent free PSA returned to baseline by 6 hours after ejaculation and then decreased below baseline by 24 hours. When normal biologic variation was accounted for, 40% of men, at 24 hours after ejaculation, had total PSA levels above the baseline level. Similarly, 24 hours after ejaculation, the percent free PSA remained above baseline level in 10% and below baseline level in 35% of the men. CONCLUSIONS: Both total and free PSA increase immediately after ejaculation, with differing rates of return to baseline levels. PSA testing within 24 hours after ejaculation may lead to an erroneous interpretation of the results of both total and percent free PSA measurements in a small proportion of men.

Biopsy↗

PubMed1997

Buccofacial apraxia and left cerebral haemorrhage.

We examined 33 patients with left intracerebral haemorrhage to investigate the relations to buccofacial apraxia (BFA). BFA was present in 18 cases at 1 month and disappeared in 3 cases and persisted in 15 cases at 6 month from the onset. The existence of BFA seems to be partially dependent the haematoma volume which may cause the organic damage in lenticulate nucleus, insula, posterior limb or internal capsule and anterior portion of paraventricle white matter. All patients with BFA had aphasia (Broca 6, Wernicke 1, Total 10, Amnestic 1). Aphasia of the patients with transient BFA improved as well as the patients without BFA after BFA disappeared. We suspected that improvement or aphasia might be affected by BFA.

Aphasia↗

PubMed1997

Cloning, sequence, and expression of a blood group B active recombinant alpha-D-galactosidase from pinto bean (Phaseolus vulgaris).

A cDNA encoding pinto bean alpha-D-galactosidase [E.C. 3.2.1.22] was obtained by amplification of cDNA using highly conserved sequences found in eucaryotic alpha-D-galactosidases. Subsequently a full length Phaseolus cDNA clone was obtained that is 1537 nt long and contains untranslated 5' and 3' sequences. The nucleotide sequence of the cDNA has a high degree of homology with other eucaryotic alpha-D-galactosidase genes. The recombinant alpha-D-galactosidase (rGal) was expressed in Escherichia coli and purified by ion exchange and affinity chromatography. Purified rGal was homogeneous by SDS-PAGE and had relative masses of 40.1 and 45.4 kDa under nonreducing and reducing conditions, respectively. The N-terminal sequence of the expressed protein contained the sequence GNGLGQTPPMG corresponding to that deduced from the cDNA sequence. The native molecular weight for rGal was determined to be 32.18 kDa by Sephacryl S-200 chromatography. The specific activity of the rGal was 349 mu moles of PNP-alpha-D-galactopyranoside hydrolyzed per mg of pure rGal per min. rGal was highly specific for alpha-D-galactosyl residues and degraded B oligosaccharide. No detectable hemagglutinin or protease activity was present in the preparations. Furthermore, rGal was active against the blood group B antigen on native human erythrocytes in cell suspension assays. The only detectable RBC phenotypic change was loss of the B and P1 epitopes. Recombinant Phaseolus vulgaris alpha-D-galactosidase may have useful biotechnical applications in the potential mass production of enzymatically converted, universally transfusable type O RBCs. alpha-D-galactosidase [E.C. 3.2.1.22] has been purified from a variety of procaryotic and eucaryotic species. Most alpha-D-galactosidases have similar low molecular weight substrate specificities, but activity against high molecular weight substrates is variable. Terminal alpha-D-galactoside residues are present in glycoproteins and glycolipids. Some alpha-D-galactosidases have activity against alpha-D-galactosyl residues on cell membrane glycoconjugates. Glycosidases with this property are useful for carbohydrate structural studies and biotechnical applications. Enzymes free of other glycosidase activities with activity near neutral pH are particularly useful for membrane modification studies on native cells. Complex sugar chains in glycolipids and glycoproteins have often been implicated in the growth and development of eucaryotes. In particular, complex sugar chains play an important role in the recognition of self in the immune system. Some alpha-D-galactosidases can modify certain carbohydrate membrane epitopes, thereby modulating the immune response. For example, the blood group B epitope expressed on erythrocytes contains a terminal alpha-D-galactosyl residue. Individuals lacking this antigen produce naturally occurring complement fixing antibodies to the B epitope. Hydrolysis of this terminal saccharide destroys the antigenic activity of the B determinant producing H antigen (blood type O) on erythrocytes. Only rare individuals produce clinically significant antibodies to the H antigen, and therefore, type O red blood cells are "universally" compatible and in great demand. Dhar purified alpha-D-galactosidase isozymes from Phaseolus vulgaris and characterized their activity. To our knowledge, our laboratory, in a brief report, is the first to describe the cloning of the gene and the use of recombinant enzyme for seroconverting blood type B to O cells. This paper describes the cloning, sequence, expression, purification, and characterization of recombinant alpha-D-galactosidase. Activity of the recombinant enzyme on the native human erythrocyte blood group B epitope is shown.

ABO Blood-Group System↗

PubMed1997

Risk of nodal metastases at laparoscopic pelvic lymphadenectomy using PSA, Gleason score, and clinical stage in men with localized prostate cancer.

Laparoscopic pelvic lymph node dissection (LPLND) is a low-morbidity procedure used to stage prostate cancer accurately prior to definitive local therapy. To better select patients for LPLND, we reviewed the clinical features of 120 patients with clinically localized prostate cancer who underwent LPLND to define significant risk factors for nodal metastases. The age ranged from 43 to 79 years (mean 68). Serum prostate specific antigen (PSA) concentration ranged from 1.3 to 329 ng/mL, Gleason score ranged from 2 to 9, and clinical stage ranged from T1b to T3c. Nodal metastases were discovered in 15 patients (13%). Among men with a Gleason score > or = 7, 21% had nodal metastases (P = 0.004). A serum PSA > 20 ng/mL and clinical stage T1b, T2b, or greater also were statistically significant predictors of lymph node metastases (20% and 19%, respectively). In multivariate analysis, Gleason score significantly predicted nodal metastases when controlling for all other clinical measures. Therefore, LPLND is indicated for any patient with a Gleason score > or = 7, PSA > 20 ng/mL, and advanced clinical T stage, independently or in combination.

Age Factors↗

PubMed1997

Alzheimer's disease and driving: prediction and assessment of driving performance.

OBJECTIVES: To examine driving competence in a group of drivers diagnosed with probable Alzheimer's Disease (AD) in terms of a standardized open road evaluation and expert judgments. To examine the validity of a standardized medical examination, including administration of the Mini-Mental Status Exam (MMSE), and a standardized neuropsychological assessment as predictors of open road driving performance. DESIGN: A prospective investigation with consecutively referred subjects. SETTING: Coorabel Driver Assessment Centre, Royal Rehabilitation Centre Sydney, Australia. PARTICIPANTS: Nineteen subjects with a diagnosis of probable AD. MEASUREMENTS: A standardized clinical medical examination, a standardized neuropsychological assessment, and a standardized open road driving evaluation. The driving evaluation provided a correct driving actions score. The outcome measure was the expert judges' rating of overall driving competence, which was termed the final on-road result. RESULTS: Seven subjects passed the on-road driving evaluation, and 12 failed. MMSE was found to be a significant predictor of final on-road result. The physician's prediction, the neuropsychology test scores, and the neuropsychologist's prediction were not found to be significantly associated with the final on-road result. The on-road driving evaluation was a reliable test. CONCLUSION: Inasmuch as all subjects except one were still driving and all wished to continue to drive, it is important to note that 63.2% of subjects failed the on-road evaluation. Conversely, 36.8% were judged safe to drive, suggesting that AD diagnosis alone may be insufficient criteria for cessation of driving. A standardized road test may be the only appropriate means of determining driving competence in people diagnosed with AD.

Aged↗

PubMed1997

Abnormal illness behaviour in rehabilitation from stroke.

OBJECTIVE: To examine the effect of abnormal illness behaviour (AIB) on rehabilitation outcome following stroke. DESIGN: A longitudinal design, with assessments on admission to and discharge from rehabilitation, and six and 12 months after discharge. SETTING: The study was undertaken in the rehabilitation unit at Repatriation General Hospital, in Adelaide, South Australia. SUBJECTS: Ninety-four 12-month stroke survivors who had undergone an inpatient rehabilitation programme. MAIN OUTCOME MEASURES: AIB was assessed using the Illness Behaviour Questionnaire. Additional psychological measurements comprised the Zung Self-Rating Depression Scale, General Health Questionnaire, and a visual analogue mood scale. Functional ability was assessed with the Australian ADL Index, and lifestyle activities with the Frenchay Activities Index. RESULTS: Cluster analysis of discharge data was used to define a rule for identifying patients with AIB. AIB was apparent in nearly 30% of patients at discharge, and persisted for 12 months. Patients with AIB scored more poorly than non-AIB patients on functional, social and psychological indicators. CONCLUSIONS: AIB emerged as a key determinant of long-term disability. It is important to consider why AIB develops during rehabilitation, and how to identify patients at risk.

Activities of Daily Living↗

PubMed1997

Functional outcome following thalamic haemorrhage: relationship between motor and cognitive functions and ADL.

Twenty-two patients with thalamic haemorrhage were examined to investigate the relationship between motor and cognitive function, and activities of daily living (ADL). Patients with unilateral spatial neglect had lower ADL scores on admission than patients without unilateral spatial neglect (Mean: 17.0 and 24.6, respectively; F = 4.38, df = 1, p < 0.05). Unilateral spatial neglect related to feeding, bowel control and transfer in Barthel index on admission. Patients with aphasia on admission had lower ADL at discharge than patients without aphasia on admission (Mean: 57.0 and 84.7, respectively; F = 7.70, df = 1, p < 0.05). Aphasia related to the bathing, toilet, stair climbing, dressing, and ambulation in Barthel index on discharge. There was a significant difference between the severity of paresis in upper and lower limb on admission and ADL at discharge. The two-way repeated measures ANOVA showed a significant difference between severity of paresis in lower limb and ADL improvement. It can be suggested that the most important predictor of outcome was paresis in lower limb, and not aphasia or unilateral spatial neglect.

Activities of Daily Living↗

PubMed1997

Effect of digital rectal examination and needle biopsy on serum total and percentage of free prostate specific antigen levels.

PURPOSE: We determined the effect of digital rectal examination and prostatic biopsy on serum total and free prostate specific antigen (PSA) concentrations in men undergoing screening for prostate cancer. MATERIALS AND METHODS: In 93 men recruited from our PSA screening program we measured the serum concentrations of total and free PSA on 3 occasions during a 30-day interval before performing digital rectal examination. Total and free PSA measurements were repeated 1 and 24 hours after the rectal examination. Serum total and free PSA also was measured immediately before, and 1 hour, 24 hours and 1 week after prostatic biopsy in 30 men. RESULTS: Biological variation for total and free PSA was 14.7 and 14.0%, respectively. At 1 hour after rectal examination total and free PSA increased by more than the biological variation in 31 and 48% of the men, respectively. Increases were significantly greater in men whose initial PSA concentrations were less than 4.0 ng./ml. There was a dramatic increase in total and percentage of free PSA in all men 1 hour after prostatic biopsy. Increases in percentage of free PSA were greater in men whose biopsies revealed cancer. Total PSA remained elevated for at least 1 week in most men, while percentage of free PSA returned to within or less than the biological variation of the baseline level in 90% of the men by 24 hours. CONCLUSIONS: Digital rectal examination causes a modest increase in total and percentage of free PSA. Prostate needle biopsy causes more dramatic increases in both forms of PSA. Free PSA is preferentially released into the serum after prostatic manipulation and appears to be cleared more rapidly than complexed PSA. The differential return of the different PSA forms to baseline levels after biopsy could affect the use of measurements of the percentage of free PSA in clinical practice.

Aged↗

PubMed1997

The impact of systematic prostate biopsy on prostate cancer incidence in men with symptomatic benign prostatic hyperplasia undergoing transurethral resection of the prostate.

PURPOSE: We determined the impact of 1 or more systematic (4 to 6 cores) needle biopsies of the prostate on the incidence of prostate cancer in men undergoing transurethral resection of the prostate for symptomatic benign prostatic hyperplasia (BPH) with elevated serum prostate specific antigen (PSA) and/or suspicious digital rectal examination. MATERIALS AND METHODS: Records were reviewed retrospectively for 85 consecutive men 54 to 85 years old who underwent transurethral resection of the prostate for symptomatic BPH. Of the men 56 (66%) had at least 1 prior benign systematic prostate biopsy. RESULTS: Cancer was detected in the transurethral resection specimen in 5 of 29 men (17.2%) who had no prior prostatic biopsy and in 9 of 56 (16.1%) who had at least 1 prior benign biopsy. Among the latter group the probability of cancer being present in the transurethral resection specimen was not related to the number of prior biopsies, PSA concentration or PSA density. Of the cancers detected in men with at least 1 prior benign biopsy 89% were clinical stage T1b or greater. CONCLUSIONS: Clinically relevant prostate cancers may be detected in a significant proportion (more than 15%) of men undergoing transurethral resection of the prostate for symptomatic BPH despite prior screening with serum PSA, digital rectal examination and 1 or more systematic needle biopsies of the prostate.

Aged↗

PubMed1997

Biological variation of total, free and percent free serum prostate specific antigen levels in screening volunteers.

PURPOSE: We determined the biological variation of the total, free and percent free serum prostate specific antigen (PSA) in men 50 years old or older. MATERIALS AND METHODS: Between July 1995 and February 1996 we studied 84 healthy men from our PSA screening study to determine biological variation by calculating the coefficients of variation of 3 PSA measurements on blood samples drawn from each subject 2 weeks apart. RESULTS: The mean coefficients of variation for total, free and percent free serum PSA were 15, 17 and 14%, respectively. Age, total PSA and ejaculation were not confounding factors in this analysis (that is multivariate R2 less than 5% for all indexes). CONCLUSIONS: There is a mean variation of approximately 15% in measurements of total, free and percent free PSA that does not appear to be significantly affected by age and total PSA level.

Aged↗