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D S Smith

Publications and source records attributed to D S Smith.

At least 109 records · Page 6Linked to original sources
PubMed1995

Effect of inflammation and benign prostatic hyperplasia on elevated serum prostate specific antigen levels.

PURPOSE: We quantify the causes of elevated serum prostate specific antigen (PSA) concentrations in men whose prostate biopsies repeatedly showed no cancer. MATERIALS AND METHODS: The effects of prostate volume, inflammation, echogenicity on ultrasound and calculi were examined in a large PSA-based screening population of 148 men with serum PSA concentrations greater than 4.0 ng./ml., findings suspicious for cancer on digital rectal examination and multiple negative biopsies. These men were selected and compared to 64 men with suspicious rectal examinations, multiple negative biopsies and serum PSA concentrations of 4.0 ng./ml. or less. RESULTS: The high PSA group had larger prostates (68 versus 33 cc, p = 0.0001) and significantly more subclinical prostatic inflammation. Acute and chronic inflammation was more prevalent in the high PSA group (63% versus 27%, p = 0.0001 and 99% versus 77%, p = 0.0001, respectively). A simultaneous regression analysis showed that prostatic size accounted for 23%, inflammation 7%, prostatic calculi 3% and nonisoechoic ultrasound lesions 1% of the serum PSA variance. CONCLUSIONS: Prostate volume and inflammation are the most important factors contributing to serum PSA elevation in men without clinically detectable prostate cancer.

Aged↗
PubMed1995

The rotator cuff.

The functional anatomy of the rotator cuff and its relationship to the mechanism of shoulder joint movements and control is now becoming more clearly understood. Common variations in the anatomy of the acromion and the subacromial region, particularly the coraco-acromial ligament, and its relationship to the tendon of the supraspinatus are now seen to be major determinants of degenerative changes in the rotator cuff. Changes in the matrix of the musculotendinous region, which may be related to mechanical interference with the vascular supply to the tendon are now a possible determinant of early degenerative changes (both primary, and those secondary to trauma) in the rotator cuff. The relationship of these findings to the management of lesions of the rotator cuff is discussed.

Humans↗
PubMed1995

Effects of hypercapnia on ECoG and oxidative metabolism in neonatal dog brain.

The effects of hypercapnia on cerebral electrical activity and mitochondrial oxidative phosphorylation were studied in the anesthetized neonatal dog by using the electrocorticogram (ECoG) and 31P-magnetic resonance spectroscopy. Three levels of hypercapnia with arterial PCO2 values of approximately 70, 100, and 140 Torr reduced the intracellular pH of the brain from 7.11 to 6.99, 6.87, and 6.76, respectively. These levels of hypercapnia also reduced ADP concentration ([ADP]) from 21.5 to 18.1, 14.8, and 12.9 microM as well as the average ECoG power output by 20, 30, and 40%. A Michaelis-Menten relationship for the mitochondrial respiratory enzymes was fitted with [ADP] and the change in the average ECoG. The result suggests that mitochondrial respiration is regulated by [ADP] and that the in vivo Michaelis-Menten constant for ADP was 21 microM, a value close to the in vitro value. The mitochondrial maximal reaction velocity was reduced by only 10% during hypercapnia and showed no relationship with the degree of acidosis, suggesting that mitochondrial respiratory enzymes are not responsible for the inhibition of the brain electrical activity.

Adenosine Diphosphate↗
PubMed1995

Catch in the primary spines of the sea urchin Eucidaris tribuloides: a brief review and a new interpretation.

Previous models of reversible catch in echinoid spines, as a property of muscle or of collagen, are briefly reviewed and discussed. This brief review offers a new interpretation of catch in primary spines of Eucidaris tribuloides, viewing the collagen and small muscles of the catch ligament working together as a variable-length tendon. In the model presented, changes in ligament length when out of catch are accommodated by sliding of discontinuous, interdigitating and cross-link-stabilized columns of collagen fibrils, the muscle layer external to the ligament effecting spine movement. Catch is viewed as a consequence of contraction of small muscles inserted on the collagen columns within the ligament. Ligament shortening tightens the profuse (ca. 30,000/mm2) and highly ordered collagen insertion loops within the stereoms of the spine base and test, and catch results from the multiplicative effect of these friction sites in series. New data are presented on novel structural cross-links between collagen fibrils. The cross-links stabilize the ligament columns. The central ligament in Eucidaris plays a purely passive mechanical role in maintaining the alignment of the spine-test articulation. It contains no muscle and neither contracts nor undergoes catch; its insertions are simple, unlike the complex stereom insertions of the main ligament.

Animals↗
PubMed1995

Competence and performance in activities of daily living of patients following rehabilitation from stroke.

Indices of activities of daily living (ADL) are commonly criticized for failing to yield other than functional information. We suggest an alternative approach in which tested functional ability (ADL competence) is distinguished from actual behaviour (ADL performance). A method of making these assessments, based on the Australian ADL Index, was trialled in a longitudinal study involving 130 patients admitted for rehabilitation following stroke. Twelve months after discharge from rehabilitation the total ADL performance score was higher, that is to say worse, than the total ADL competence score; further, there was no significant agreement between the competence and performance ratings for nine of the 17 activities. It appears that ADL competence and ADL performance can be distinguished both theoretically and empirically. Two case studies illustrate the usefulness of the performance assessment. We recommend the ADL performance assessment as an outcome measure in rehabilitation.

Activities of Daily Living↗
PubMed1995

The development of a purification procedure for saxitoxin-induced protein.

A simple economical procedure for purifying saxitoxin-induced protein (SIP) from crude extracts of the small shore crab, Hemigrapsus oregenesis, was developed. (NH4)2SO4 precipitation, chymotrypsin digestion, heat treatment, gel filtration and ion-exchange-chromatography procedures were evaluated in purifying SIP. An enzyme immunoassay was used to determine the SIP yield and relative purity at each step of three procedures, thus permitting an assessment of the conditions required for maximum recovery. Response surface analysis was used in an attempt to determine the optimum temperature and exposure time for the heat treatment. A 20 min incubation at 65 degrees C was confirmed by electrophoretic analysis to be the best combination of time and temperature for achieving both an acceptable yield and purity of SIP. SIP in desalted concentrate was shown to be resistant to chymotrypsin proteolysis; however, this enzyme had deleterious effects on SIP purification at later stages of the procedure. The omission of the chymotrypsin digestion, and the inclusion of gel-filtration chromatography in the final clean-up step, resulted in the purification of SIP comparable with that achieved with affinity chromatography.

Ammonium Sulfate↗
PubMed1994

Changes over four years in musculoskeletal impairment in men and women.

OBJECTIVE: To measure changes over four years in musculoskeletal impairment in a group of healthy adults. DESIGN: Longitudinal intervention study with repeated questionnaire assessments at entry, two and four years. SUBJECTS: Adults who volunteered for a fitness program and complied with all three assessments (373 men and 259 women; mean age 42 years). RESULTS: The general four-year trend was an acceleration of musculoskeletal impairment of about 10% per year for three indicators. Movement limited activities increased to a similar extent in men and women; women showed greater increases in pain or discomfort and specialist consultations. For both sexes the most vulnerable anatomical locations were the lower back, neck and knees, while the most common activities associated with movement limitations were jogging and lifting. Pain or discomfort and movement limited activities were age related. CONCLUSIONS: The findings justify anxieties about the increasing costs of musculoskeletal impairment, and highlight important questions about the nature, monitoring and control of such impairment.

Adult↗
PubMed1994

Comparison of spouse and nonkin controls: the experience of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD).

Normal spouses may be an excellent source of control subjects in research on noninstitutionalized Alzheimer's disease (AD) cases. To determine to what extent spouses might differ from nonkin controls, we compared information on 145 spouses of AD patients with 158 nonkin community volunteers enrolled by 23 centers of the Consortium to Establish a Registry for Alzheimer's Disease. Chi square and 1-way ANOVA analyses indicate that neither at entry nor over the next two years did the two groups of controls differ significantly on demographic characteristics, health status, or performance on neuropsychological measures. However, hierarchical logistic regression showed that, after controlling for demographic characteristics and physical status, dropout was nearly twice as high among spouse controls. Dropout was related to nonreturn of the AD case. Thus, as controls, spouses are viable as long as the cases to whom they are married remain in the study.

Aged↗
PubMed1994

Using Functional Independence Measure profiles as an index of outcome in the rehabilitation of brain-injured patients.

Rehabilitation preserves and restores everyday functions in people who have disabilities. Functional change for patients undergoing a rehabilitation program is the best measure of the effectiveness of the rehabilitation program. One tool used for measuring function is the Functional Independence Measure (FIM). However, there are problems with the psychometric properties of FIM. This article presents a method for using FIM with median patient profiles. We show the method with data from 53 patients. The results show a relationship between the pattern of recovery and the length of stay in the unit. Spearman's rank order correlation coefficients confirm this observation. Median patient profiles prove to be a useful method of displaying data as outcome measures of the effectiveness of a rehabilitation program.

Activities of Daily Living↗
PubMed1994

Development of a monoclonal-based enzyme-linked immunoassay for saxitoxin-induced protein.

A monoclonal antibody was generated against saxitoxin-induced protein (SIP) from the small shore crab Hemigrapsus oregenesis. SIP was induced by saxitoxin injection and could be detected in the crude crab extracts with both polyclonal and monoclonal antibody preparations. On Western blots, the polyclonal serum reacted against several bands which were induced by saxitoxin in the crude extracts. These bands represented proteins related to SIP. The monoclonal (4G5), however, was specific for the 79,000 mol. wt subunit of SIP. A triple antibody sandwich ELISA was developed in which polyclonal anti-SIP IgG was used as a trapping layer and monoclonal 4G5 was used as the detection layer. This assay was shown to be more specific and more accurate than a direct bind assay which employed the polyclonal antiserum alone. Although the polyclonal serum was more sensitive than the monoclonal on Western blots, the triple antibody sandwich and direct bind ELISAs were of comparable sensitivity.

Animals↗
PubMed1994

A competitive enzyme-linked immunoassay for domoic acid determination in human body fluids.

A polyclonal antiserum was raised in mice against domoic acid. Two of three immunogens consisted of domoic acid coupled to ovalbumin (OVA) and keyhole limpet haemocyanin at molar ratios of 47:1 and 44:1, respectively using a carbodiimide reaction. Titres of both antisera exceeded 1/35,000 against domoic acid coupled to the non-relevant carrier. Domoic acid was also conjugated to bovine serum albumin at a molar ratio of 30:1 using N-hydroxysuccinimidyl-4-azidobenzoate, a photoreactive compound. This immunogen, however, produced no measurable serum titres against domoic acid. The antiserum produced against the OVA conjugate displayed the highest affinity for free domoic acid in competitive enzyme-linked immunosorbent assay (ELISA). Furthermore, this antiserum preparation did not significantly cross-react with glutamic acid, aspartic acid, the structural analogue kainic acid, or the paralytic shellfish toxin, saxitoxin. The competitive ELISA was used to quantify domoic acid concentrations in human body fluids spiked with pure domoate. The lower limits of accurate domoic acid determinations in competitive ELISA were 0.2 micrograms/ml in urine, 0.25 micrograms/ml in plasma and 10 micrograms/ml in milk. It was concluded that the competitive ELISA described herein could be used to quantitate directly the concentration of domoic acid in the body fluids of individuals with amnesic shellfish poisoning.

Animals↗
PubMed1994

The nature of prostate cancer detected through prostate specific antigen based screening.

Prostate specific antigen (PSA) based screening nearly doubles the detection rate of early prostate cancer. However, it is unknown whether the additional tumors detected are medically important. Traditional clinical and pathological features associated with medically important cancer include a palpable tumor, multifocal or diffuse involvement and moderately or poorly differentiated histology. In contrast, microfocal, well differentiated tumors are considered to be possibly medically unimportant. We sought to examine the clinical and pathological tumor stage and tumor grade in 1,169 consecutive men whose prostate cancer was detected during serial PSA based screening protocols involving 24,346 men screened at 6-month intervals. Of the patients 97% had clinically localized (clinical stage T1 or T2) tumors, of which 39% were not palpable (stage T1). Of the men whose cancer was detected through initial screening who underwent surgical staging 69% had pathologically organ confined (pathological stage whose cancer was detected through initial screening pT1 or pT2) disease compared to 74% whose cancer was detected through serial screening (after an initially negative screening). Impalpable, clinically focal, well differentiated minimal tumors were noted in 16% of the men. However, only 3% of the men who underwent surgical staging had impalpable, pathologically microfocal, well differentiated minimal tumors. We conclude that the majority of tumors detected through PSA based screening have the clinical and pathological features associated with medically important prostate cancer.

Aged↗
PubMed1994

5-year tumor recurrence rates after anatomical radical retropubic prostatectomy for prostate cancer.

The new anatomical approach to radical retropubic prostatectomy with its nerve sparing option allows for preservation of erections, improved urinary continence, decreased blood loss, and lower operative mortality and morbidity rates. We sought to evaluate cancer control with this operation by determining the 5-year tumor recurrence rates using detectable serum prostate specific antigen levels as a criterion for tumor recurrence in a series of 925 consecutive men with clinical stage T1 or T2 prostate cancer. Overall, the 5-year probability of nonprogression was 78% (95% confidence limits 74 to 82%). The 5-year nonprogression rate was higher in patients whose tumors were not palpable (90% for impalpable tumors detected through transurethral resection of the prostate, 97% for impalpable prostate specific antigen detected tumors and 74% for palpable tumors). Nonprogression correlated with pathological tumor stage (91% for organ confined disease, 74% for positive margins or microscopic capsular perforation, 32% for seminal vesical invasion and virtually nil for lymph node metastases) and tumor grade (89% for well, 78% for moderately and 51% for poorly differentiated tumors). We conclude that anatomical radical prostatectomy achieves excellent cancer control for patients with organ confined prostate cancer.

Adult↗
PubMed1994

Early complications of contemporary anatomical radical retropubic prostatectomy.

Anatomical radical retropubic prostatectomy is commonly performed to treat select patients with clinically localized prostate cancer. Because this recently introduced surgical technique is technically demanding, and since early detection programs have altered the age and stage distribution of men undergoing radical prostatectomy, earlier reports describing complication and death rates from radical prostatectomy may not accurately reflect contemporary experience. A retrospective review of 1,342 radical retropubic prostatectomies performed during a 5-year period showed an early complication rate of 7.4%. The most common complications were thromboembolic (pulmonary embolism) and cardiac (myocardial infarction). Patient age, mode of diagnosis (transurethral resection of the prostate versus needle biopsy) and pathological stage of the tumor did not correlate with the rate of complications. Three patients died in this series (0.2%). This retrospective review shows that contemporary anatomical retropubic radical prostatectomy may be performed with acceptably low early morbidity and mortality rates, and that appropriate selection of chronologically older patients is not associated with significantly greater rates of early complications. These data may be useful in decision analytic models evaluating the role of therapy for patients with early stage prostate cancer.

Adult↗
PubMed1994

Artificial neural networks in the diagnosis and prognosis of prostate cancer: a pilot study.

There is controversy about how prostate cancer screening tests should best be used because of the false-negative and false-positive results. There also is controversy about prostate cancer treatment because of errors in tumor staging, uncertainty about treatment efficacy and the variable natural history of the disease. We sought to determine in a pilot study whether artificial neural networks would be helpful to predict biopsy results in men with abnormal screening test(s) and to predict treatment outcome after radical prostatectomy. To predict biopsy results, we extracted data from a prostate specific antigen (PSA) based screening study data base in 1,787 men with a serum PSA concentration of more than 4.0 ng./ml. (approximately 40% of the men also had suspicious findings on digital rectal examination). To predict cancer recurrence after radical prostatectomy, we extracted data from a random sample of 240 patients selected from a data base of men who had undergone radical prostatectomy. The neural network predicted the biopsy result with 87% overall accuracy, and its output threshold could be adjusted to achieve the desired tradeoff between sensitivity and specificity. It also predicted tumor recurrence with 90% overall accuracy. We conclude that trained neural networks may be useful in decision making for prostate cancer patients.

Aged↗