Accuracy of co-morbidity data in patients undergoing abdominal wall hernia repair: a retrospective study.

OBJECTIVES: To determine the baseline accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of routinely collected co-morbidity data in patients undergoing abdominal wall hernia repair. METHODS: All patients aged > 18 who underwent umbilical, para-umbilical, inguinal or incisional hernia repair between 1 January 2015 and 1 November 2016 were identified. All parts of the clinical notes were searched for co-morbidities by two authors independently. The following co-morbidities were considered: hypertension, ischaemic heart disease (IHD), diabetes, asthma, chronic obstructive pulmonary disease (COPD), cerebrovascular disease (CVD), chronic kidney disease (CKD), hypercholesterolemia, obesity and smoking. The co-morbidities data from clinical notes were compared with corresponding data in hospital episode statistics (HES) database to calculate accuracy, sensitivity, specificity, PPV and NPV of HES codes for co-morbidities. To assess the agreement between clinical notes and HES data, we also calculated Cohen's Kappa index value as a more robust measure of agreement. RESULTS: Overall, 346 patients comprising 3460 co-morbidity codes were included in the study. The overall accuracy of HES codes for all co-morbidities was 77% (Kappa: 0.13). When calculated separately for each co-morbidity, the accuracy was 72% (Kappa: 0.113) for hypertension, 82% (Kappa: 0.232) for IHD, 85% (Kappa: 0.203) for diabetes, 86% (Kappa: 0.287) for asthma, 91% (Kappa: 0.339) for COPD, 92% (Kappa: 0.374) for CVD, 94% (Kappa: 0.424) for CKD, 74% (Kappa: 0.074) for hypercholesterolemia, 71% (Kappa: 0.66) for obesity and 24% (Kappa: 0.005) for smoking. The overall sensitivity, specificity, PPV and NPV of HES codes were 9, 100, 100, and 77%, respectively. The results were consistent when individual co-morbidities were analyzed separately. CONCLUSIONS: Our results demonstrated that HES co-morbidity codes in patients undergoing abdominal wall hernia repair are specific with good positive predictive value; however, they have substandard accuracy, sensitivity, and negative predictive value. The presence of a relatively large number of false negative or missed cases in HES database explains our findings. Better documentation of co-morbidities in admission clerking proforma may help to improve the quality of source documents for coders, which in turn may improve the accuracy of coding.

Dictyostelium discoideum plasmid containing an AP-endonuclease upstream sequence: bleomycin induction of a luciferase reporter.

A sequence of 1624 bp 5' to the apurinic/apyrimidinic (AP) endonuclease structural gene of Dictyostelium discoideum (APEA) has been inserted upstream of the luciferase reporter gene in pVTL2, an autonomously replicating nuclear plasmid in this organism. Cells transformed with this plasmid, designated pVTL-AL, displayed strong luciferase induction during treatment with the DNA-damaging agent bleomycin. For example, a luciferase activity of 45-fold above the constitutive level was observed for 20 hours of growth in axenic medium with 0.002 U/mL of bleomycin. The response was bleomycin concentration-dependent. Cell survival was greater than 90% for all treatments. The level of luciferase expression was highly dependent on the cell growth conditions, with the greatest induction observed for stationary phase axenically-grown cells. This effect may be related to a variation of plasmid copy number with growth conditions.

United States passenger-vehicle crashes by crash geometry: direct costs and other losses.

The personal and societal losses caused by motor-vehicle crashes are significant. This paper provides tools that describe these losses for 30 different crash geometries. Persons involved with the development and implementation of crash countermeasures can use these tools to prioritize their countermeasure approach. Multiple vehicle crashes currently account for much larger direct costs but only slightly more years lost than single vehicle crashes. Direct expenditures on multiple vehicle crashes exceed $41 billion per year; they claim 974,000 years of life and functioning. Direct expenditures on single vehicle crashes exceed $18 billion per year; they claim 937,000 years of life and functioning.

Apurinic/apyrimidinic (AP) endonuclease from Dictyostelium discoideum: cloning, nucleotide sequence and induction by sublethal levels of DNA damaging agents.

We have cloned an AP endonuclease gene (APEA) from Dictyostelium discoideum, along with 1.8 kb of the 5' flanking region. There are no introns. The sequence predicts a protein of 361 amino acids, showing high homology to the major human/Escherichia coli exonuclease III family of AP endonucleases. There is 47% identity and 64% similarity to the Ape endonuclease of human cells using the C-terminal 257 amino acids of the Dictyostelium protein. The 104 amino acids on the N-terminus show only low homology with other AP endonucleases. Instead, this region shows high homology with the acid-rich regions of proteins associated with chromatin, such as nucleolins and HMG proteins. The gene is transcriptionally activated up to 7-fold after treatment of cells with sublethal levels of DNA damaging agents, including ultraviolet light, MNNG and bleomycin. Induction does not occur following blocking of replication fork polymerases with aphidicolin. It is not eliminated by treatment with kinase or phosphatase inhibitors. Four DNA damage-sensitive mutants all retained the DNA damage-induced up-regulation.

Some repair-deficient mutants of Dictyostelium discoideum display enhanced susceptibilities to bleomycin.

Dictyostelium discoideum, a soil eukaryote, is highly resistant to DNA-damaging agents; repair mutants are more susceptible. Susceptibility to bleomycin, produced by Streptomyces verticillus, is greater for mutants which are susceptible to other agents than for resistant strains. The high potential for DNA repair may result from the need to cope with chemicals produced by other soil microorganisms.

Microvascularity in benign prostatic hyperplasia.

The vascular density of benign prostatic hyperplasia (BPH) has not been characterized. Previously we reported vessel density (vv/mm2) in prostatic carcinoma was twice that of normal prostate [Bigler et al.: Hum Pathol 24:220-226 1993]. To further characterize vessel density in benign prostate tissue we examined 15 cases of BPH obtained by open prostatectomy. Vessels were stained with antibodies to Factor VIII-related antigen, and vessel density was measured using computer-assisted image analysis. Vessel density was analyzed between various histologic tissue types. Mean vessel density in all transition zone tissue was 70.2 vv/mm2. Vessel density in epithelial hyperplastic nodules (mean 99.3, SD 40.7) exhibited density levels similar to those found in prostatic carcinoma (mean 101.4, SD 35.6). Vessel density in epithelial nodules was significantly higher than in non-nodular epithelial tissue (mean 76.7, SD 23.1; P < 0.001, ratio = 1.3). Higher vessel densities were found in hypercellular stromal nodules (mean 64.7, SD 19.1) than in adjacent stromal areas (mean 36.5, SD 15.3; P < 0.001, ratio = 1.8). Overall, vessel density in BPH was higher than previously found in benign tissue measured in radical prostatectomy specimens, especially in areas of nodular morphology.

Dictyostelium discoideum, a lower eukaryote model for the study of DNA repair: implications for the role of DNA-damaging chemicals in the evolution of repair proficient cells.

The evolution of the ability of living cells to cope with stress is crucial for the maintenance of their genetic integrity. Yet low levels of mutation must remain to allow adaptation to environmental changes. The cellular slime mold D. discoideum is a good system for studying molecular aspects of the repair of lethal and mutagenic damage to DNA by radiation and chemicals. The wild-type strains of this soil microorganism are extremely resistant to DNA damaging agents. In nature the amoeboid cells in their replicative stage feed on soil bacteria and are exposed to numerous DNA-damaging chemicals produced by various soil microorganisms. It is probable that the evolution of repair systems in this organism and perhaps in others is a consequence of the necessity to cope with chemical damage which also confers resistance to radiation.

Morphometric quantitation of stroma in human benign prostatic hyperplasia.

OBJECTIVES: Human benign prostatic hyperplasia (BPH) consists of three major histologic components: stroma, epithelium, and luminal space. For the relief of bladder outlet obstruction caused by BPH, quantitation of the histologic composition of BPH may aid in selecting treatment. To investigate variation between patients in the stromal percentage of BPH, we performed quantitative morphometry on specimens from patients with clinically significant bladder outlet obstruction obtained by three procedures: open prostatectomy, transurethral resection of the prostate (TURP), and prostate needle biopsy (PNB) just prior to TURP. METHODS: Ten specimens obtained by each surgical procedure were analyzed. Specimens were stained with antibody to muscle-specific actin to mark the stroma; quantitation of stroma was accomplished by computer image analysis. RESULTS: The percentage of stroma in all BPH cases ranged from 49.9% to 76.7% (mean, 65.4%, SD = 7.4). No significant difference was observed when comparing samples obtained by the three procedures (p = 0.70). Smooth muscle stromal composition was also quantified in PNB specimens. For these samples, a significant inverse relationship was found between the percentage stroma in the biopsy and the percentage of stroma composed of smooth muscle (r2 = 0.49; p = 0.021). CONCLUSIONS: The data demonstrated that the largest component of BPH was stroma, which comprised approximately 50% to 75% of the total hyperplastic tissue. The mean and range of stromal percentage were similar whether investigating large tissue samples from open prostatectomies or small samples from needle biopsies. PNB data indicated that an increased percentage of stroma may be due to increased nonmuscular elements in the stroma.

Differential repair of UV damage in a developmentally regulated gene of Dictyostelium discoideum.

The repair of cyclobutane pyrimidine dimers was measured under non-replicating conditions in a 2054-bp fragment of a cAMP-inducible cysteine proteinase (CP2) gene in D. discoideum. Overall genomic repair was unaffected by cAMP. The removal of dimers from CP2 in the wild-type NP2 cells as quantified using T4 endonuclease V was independent of transcription and was the same as in the overall genome. In a UV-sensitive radC mutant in which the rate of overall dimer removal was previously shown to be reduced, the initial rate of dimer removal in the uninduced CP2 gene (-cAMP) was 3-fold lower compared to the induced gene (+cAMP), in which repair was identical to that for the induced and uninduced states of NP2. D. discoideum may have two pathways for repairing dimers. One, effective in the wild-type strain but of reduced efficiency in radC repairs dimers equally well independent of transcription and at about the same rate as in the overall genome. A second pathway, retained in radC, repairs dimers more slowly in the overall genome and in the uninduced CP2 gene while undergoing the wild-type rate of repair in the transcriptionally active gene. Hence radC has reduced ability to repair transcriptionally inactive DNA, a defect similar to that of xeroderma pigmentosum group C.

Predictors of pathologic stage in prostatic carcinoma. The role of neovascularity.

BACKGROUND: Prostate adenocarcinoma is a significant cause of morbidity and mortality in older men. However, the histologic prevalence far exceeds clinically manifest disease. Increased screening has resulted in the detection of a large number of carcinomas of unknown malignant potential. The authors investigated tumor angiogenesis to predict pathologic stage in prostatic tumors. Angiogenesis in prostatic intraepithelial neoplasia (PIN), a putative premalignant lesion, also was investigated. METHODS: Immunohistochemistry was used to highlight the tumor vasculature. Vessels were quantified using computerized image analysis. A minimum of five randomly selected microscopic fields were measured from each tumor. To investigate PIN, the authors measured vessels per millimeter of gland perimeter, compared with benign glands in the same patient. RESULTS: Vessel density (vessels per millimeter squared [vv/mm2]) correlated with pathologic stage. The mean vessel density of organ-confined tumors was 80.2 vv/mm2 (95% confidence interval [CI], 71.4-91.0), compared with 110.4 vv/mm2 (95% CI, 97.9-122.8) for tumors with capsular penetration or positive lymph nodes. Logistic regression analysis and modeling showed vessel density superior to histologic grade and preoperative prostate-specific antigen (PSA) level in distinguishing organ-confined tumors from those having extracapsular extension or pelvic lymph node metastasis. PIN in acini and ductules had increased microvascularity relative to benign epithelium in 18 of 25 tumors (P < 0.05). CONCLUSIONS: Neovascularity has been demonstrated to be a prerequisite for tumor progression. These data demonstrate that microvessel density in prostatic carcinoma is an independent predictor of pathologic stage and, presumably, malignant potential. Quantification of tumor angiogenesis may allow stratification of patients to type of treatment and may allow selection of expectant management for men with low tumor microvessel density.

Selenium status of infants is influenced by supplementation of formula or maternal diets.

Plasma selenium of infants fed proprietary formula was significantly less than that in infants fed human milk. Addition of selenite to the formula (0.253 mumol Se/L) increased plasma selenium and activities of glutathione peroxidase (GPx) and total peroxidase (Px). However, erythrocyte selenium decreased significantly during the 12-wk study in infants receiving human milk or formula with or without supplemental selenite. Infants fed human milk from women receiving 0 or 200 micrograms supplemental selenium as selenomethionine or selenium-enriched yeast had plasma selenium that paralleled changes in their selenium intake. Plasma GPx and Px activities were unrelated to human milk selenium intake. Milk from women given either selenium supplement prevented the decline in infant erythrocyte selenium. Results of these studies suggest that the method of feeding modifies the infant's apparent selenium status and that the molecular form of selenium provided and/or its interaction with other milk constituents are determinants of infant selenium status.

Selenium status of lactating women is affected by the form of selenium consumed.

The impact of providing selenomethionine (2.7 mumol Se) or selenium-enriched yeast (2.9 mumol Se) on the selenium status of lactating and nonlactating women with customary intakes of approximately 1.3 mumol Se/d was studied. Plasma selenium declined in unsupplemented lactating women but not in nonlactating women. Selenomethionine increased plasma selenium in both lactating and nonlactating women whereas selenium-enriched yeast increased plasma selenium only in nonlactating women. Erythrocyte selenium concentration was not significantly modified by lactation. Plasma glutathione peroxidase (GPx) activity decreased with duration of lactation in unsupplemented women and selenomethionine or selenium-enriched yeast supplementation prevented the decline. Milk selenium declined markedly for 20 wk after parturition in unsupplemented women. Selenomethionine significantly increased milk selenium concentrations whereas selenium-enriched yeast prevented a decline. These results clearly show that the source of selenium provided to lactating women can significantly influence selected indexes of selenium status, including milk selenium concentration.

Comparison of microscopic vascularity in benign and malignant prostate tissue.

A variety of malignant neoplasms have been shown to induce capillary neovascularization, and in some cases the degree of vascularization appears to correlate with aggressive behavior and risk of metastasis. We hypothesized that carcinoma of the prostate also induces the formation of new capillaries, and we developed a method to quantify the relative density of microscopic vessels in carcinoma of the prostate compared with benign prostatic glandular tissue. The number of microvessel profiles in tissue sections was quantified by marking the vascular endothelial cells with antibodies to factor VIII-related antigen using standard immunohistochemistry techniques and comparing fields of adenocarcinoma with benign glandular tissue in 15 radical prostatectomy specimens. The analysis was facilitated by using the Optimas computerized image analysis system (Bioscan, Seattle, WA) with software written for this investigation. Fourteen of the 15 cases demonstrated significantly higher vascular density in the areas of carcinoma than in the benign tissues. Overall, the ratio of vessels per unit area in sections of carcinoma versus benign tissue was approximately double (ratio = 2.02; P < .001). In benign tissues the capillaries are restricted for the most part to the periglandular stroma immediately adjacent to the epithelium, whereas the distribution in carcinoma appears to be more random. The data demonstrate the increased density of capillaries in prostatic carcinoma when compared with benign prostate tissue.

Mutations affecting sensitivity of the cellular slime mold Dictyostelium discoideum to DNA-damaging agents.

We describe 22 new mutants of D. discoideum that are sensitive to DNA damage. These mutants were isolated on the basis of sensitivity to either temperature, gamma-rays, or 4-nitroquinolone-1-oxide (4NQO). The doses of gamma-rays, ultraviolet light (UV), and 4NQO required to reduce the survival of colony-forming ability of these mutants to 10% (D10) range from 2% to 100% of the D10s for the nonmutant, parent strains. For most of the mutants, those which are very sensitive to one agent are very sensitive to all agents tested and those which are moderately sensitive to one agent, are moderately sensitive to all agents tested. One mutant is sensitive only to 4NQO. Linkage relationships have been examined for 13 of these mutants. This linkage information was used to design complementation tests to determine allelism with previously characterized complementation groups affecting sensitivity to radiation. 4 of the new mutants fall within previously identified complementation groups and 3 new complementation groups have been identified (radJ, radK and radL). Other new loci probably also exist among these new mutants. This brings the number of characterized mutants of D. discoideum which are sensitive to DNA-damaging agents to 33 and the number of assigned complementation groups to 11.

Quantitative morphometric analysis of the microcirculation in prostate carcinoma.

Many neoplasms have been shown to induce capillary neovascularization and this may correlate with aggressive behavior. We investigated the phenomenon of neovascularity in benign and malignant prostatic tissue. Microvessel profiles and tissue sections were visualized by antibodies to Factor VIII and standard immunohistochemical techniques, and quantified utilizing the Optimas computerized image analysis system. Microvessel density was compared in benign and cancerous portions of 15 radical prostatectomy specimens. Fourteen of 15 cases demonstrated significantly higher vascular density in the area of carcinoma as compared with benign tissue (ratio = 2.02, p < 0.001). Distribution of microvessels within malignancy was random, whereas it was restricted primarily to the periglandular space in benign tissue. Among 20 men undergoing radical retropubic prostatectomy, there was a correlation between the vessel density and the pathologic stage. No patient with organ-confined carcinoma or cancer penetrating (but not perforating) the capsule had microvessel density greater than 156 microvessels/mm2. In contrast, six of 15 men with more advanced pathologic stage exceeded this arbitrary threshold. These data demonstrate both increased vascularity of prostatic carcinoma as compared with benign tissue, and a further correlation between pathologic stage and vascularity. Microvessel density may be useful as a prognostic indicator.

Identification and characterization of a Dictyostelium discoideum ribosomal protein gene.

We have identified a developmentally repressed large-subunit ribosomal protein gene of Dictyostelium discoideum based on sequence similarity to other ribosomal proteins. Protein rpl7 is homologous to large subunit ribosomal proteins from the rat and possibly to Mycoplasma capricolum and Escherichia coli, but is not similar to three sequenced ribosomal proteins in Dictyostelium. The rpl7 gene is present at one copy per genome, as are six other cloned Dictyostelium ribosomal proteins. Restriction fragment length polymorphisms exist for ribosomal protein genes rpl7, rp1024, and rp110 in strain HU182; most Dictyostelium ribosomal protein genes examined are linked no closer than 30-100 kb to each other in the genome. Dictyostelium ribosomal proteins are known to be developmentally regulated, and levels of rpl7 transcript gradually decrease during the 24-hour development cycle. This drop correlates with that of rp1024, indicating these and other ribosomal protein genes may be coordinately regulated. To determine the cellular location of the protein, we raised antibodies to an rpl7-derived branched synthetic peptide. These antibodies cross-reacted with one protein of the expected size in a ribosomal protein fraction of Dictyostelium, indicating that the product of gene rpl7 is localized in the ribosome.

Nuclear DNA synthesis is blocked by UV irradiation in Dictyostelium discoideum.

We have used a thymidine auxotroph of the simple eukaryote, Dictyostelium discoideum and alkaline sucrose gradients of isolated nuclei to study alterations in DNA synthesis following irradiation of replicating haploid cells with 254 nm UV light. Three responses were characterized using pulse-chase protocols: (1) Lags in DNA synthesis as measured by the amount of label incorporated were 4, 9, and 20 h after 10, 50, and 200 J/m2. (2) The DNA synthesized during a 15-min pulse immediately after irradiation was of lower single strand molecular weight: 7, 3.5, and 3 x 10(6) dalton after 0, 50, and 200 J/m2. (3) The time required for maturation of the nascent DNA to full-sized single strands of about 2 x 10(8) dalton was 45-50 min for unirradiated cells, 3 h after 10 J/m2, and 20 h after 200 J/m2. The DNA of the irradiated cells did not mature uniformly during these delays; instead, a period of no increase in size was followed by a rapid, nearly control rate of maturation. We conclude: (a) at least some UV lesions block elongation of replicons; (b) the elongation of the replicons and their subsequent joining to yield mature high molecular weight DNA occurs after most of the lesions are repaired; (c) the timing of the different aspects of recovery suggest that initiation of replication is also inhibited.

Genetic analysis of two mutations affecting thymidine metabolism in Dictyostelium discoideum.

The tmpA600 mutation confers thymidylate synthase deficiency and thymidine auxotrophy to Dictyostelium discoideum. The tdrA600 mutation enhances transport of thymidine and thereby reduces the auxotrophic requirement of tmpA600 strains. The tmpA locus maps to linkage group III. The tdrA600 mutation is dominant and cosegregates with both linkage groups IV and VI, possibly because of a translocation between the two. The tdrA600 allele is sufficient to allow efficient incorporation of exogenous [3H]thymidine or [3H]uridine into TCA-precipitable material and to sensitize the cell to the nucleoside-analog inhibitor, 5-fluorodeoxyuridine. These properties make the tdrA mutation useful for studies requiring labelling of DNA or RNA in vivo.

Enhanced thymidine uptake causes the lowered thymidine requirement of D. discoideum auxotroph HPS 401.

Dictyostelium discoideum strain HPS 401 contains a spontaneous mutation that lowers the amount of thymidine required for cell growth relative to that of the auxotrophic parental strain HPS 400. Growth studies in defined medium show that as little as 8 micrograms thymidine/ml supports maximal growth of HPS 401, whereas 50 micrograms/ml is required by HPS 400. In contrast, both strains require over 40 micrograms thymidylate/ml to achieve maximal growth. HPS 401 exhibits thymidineless death when grown without thymidine; relative viability decreases to less than 0.01% after 190 h incubation. Assays for enzymes related to thymidine metabolism reveal that none of the strains tested (HPS 401, HPS 400, and prototrophic HPS 83 cells) contain detectable thymidine phosphorylase activity and that the specific activity of thymidine kinase is the same in these three strains. Thin-layer chromatography of extracts from cells grown on radiolabeled thymidine shows that there is no detectable conversion of thymidine to thymine in any of these strains. These analyses show that HPS 401 has rapid intracellular accumulation of thymidine, while only slight uptake is observed with HPS 400 or wild-type strains. HPS 401 also shows greater uptake of uridine in comparison to HPS 400 and wild-type cells. Thymidylate uptake was the same for all three strains. Thus, the mutation giving rise to the HPS 401 phenotype selectively increases the uptake of thymidine into the cell, where it can be efficiently utilized for DNA synthesis by the "salvage" pathways of nucleotide metabolism.