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Biomedical subjects

S Linn

Publications and source records attributed to S Linn.

At least 73 records · Page 4Linked to original sources
PubMed1995

The injury severity score--importance and uses.

The development and attributes of the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS) are reviewed. The ISS was proved to be an excellent method for retrospective comparison of overall injury data between populations differing in time or space. Its strengths, purpose, and appropriate uses are emphasized, together with specific comments on statistical analyses and combined scales of anatomic and physiologic injury.

Abbreviated Injury Scale↗
PubMed1995

Calcium and vitamin D enriched diets increase and preserve vertebral mineral content in aging laboratory rats.

To assess the long-term effect of vitamin D or calcium supplementation on the skeletal metabolism of aging laboratory rodents, 1.5-month-old female Wistar rats were fed with diets containing twice the concentration of vitamin D (group 2) and of calcium (group 3) as in the usual rat chow. Follow-up to 24 months of age did not show significant differences between the enriched-diet groups and the controls (group 1) in terms of the vertebral body weight and protein content. Significantly higher bone mineral contents were found in groups 2 and 3 than were found in controls, as revealed by an increased bone mineral density (BMD: +62%, group 2; +48%, group 3) and vertebral calcium content (+73%, group 2; +84%, group 3). The vertebral alkaline phosphatase enzymatic activity was significantly lower in the enriched diet groups than in controls (-47%, group 2; -45%, group 3). The ratio alkaline phosphatase/acid phosphatase activity was markedly reduced in groups 2 and 3 (-57% and -59%, respectively), which might indicate a diminished rate of bone turnover. The trabecular bone volume (BV/TV) decreased in all groups during senescence, being significantly elevated in group 3 as compared to controls. Vitamin D and calcium dietary supplementations increase the axial mineral bone content in laboratory rats and might reduce the bone turnover. Their influence on the trabecular bone volume has yet to be examined.

Absorptiometry, Photon↗
PubMed1995

Anxiety disorders among patients in a general emergency service in Israel.

OBJECTIVE: Several studies have suggested that many patients with anxiety disorders present in nonpsychiatric medical settings such as primary care facilities, emergency services, and general practice. This study examined the prevalence of panic disorder and generalized anxiety disorder among patients admitted to the general emergency service at an urban medical center in Israel. METHODS: Four groups totaling 517 patients were assessed. The groups consisted of patients presenting with somatic complaints for whom no physical condition was diagnosed, patients with somatic complaints found to have a physical disorder, a group of nonpsychiatric consecutive admissions to the emergency service, and a group of referrals to the psychiatric emergency service. RESULTS: The prevalence of panic disorder and generalized anxiety disorder in the entire sample was 2.7 percent, which is comparable to the prevalence rates reported in various community studies. However, the prevalence among patients with somatic complaints but no physical disorder was 6.7 percent, significantly higher than in the nonpsychiatric comparison groups. The prevalence in the group of psychiatric referrals was 4.8 percent. CONCLUSIONS: A population at risk for higher prevalence of anxiety disorders can be identified among patients seen in an emergency service. Physicians in primary care settings and general emergency services should consider anxiety disorders in the differential diagnosis of patients with somatic complaints but without a diagnosis of physical disorder.

Adolescent↗
PubMed1994

Three chemically distinct types of oxidants formed by iron-mediated Fenton reactions in the presence of DNA.

Exposure of Escherichia coli to H2O2 leads to two kinetically distinguishable modes of killing: mode I killing occurs maximally near 2 mM H2O2, whereas mode II killing is essentially independent of H2O2 concentrations up to 20 mM. A major portion of H2O2 toxicity is attributed to DNA damage caused by the iron-mediated Fenton reaction. By studying DNA damage during Fenton reactions in vitro, the same complex kinetics were observed and three types of oxidants were distinguished based upon their reactivities toward H2O2 and alcohols and upon iron-chelator effects. Type I oxidants are sensitive to H2O2 but moderately resistant to ethanol; type II oxidants are resistant to both H2O2 and ethanol; type III oxidants are sensitive to H2O2, ethanol, and t-butanol. To explain these results, we hypothesize that type I oxidants are generated upon Fe2+ associated with DNA only through electrostatic interactions and cause mode I killing of E. coli; type II oxidants arise upon Fe2+, which is at least partially base-associated, and cause mode II killing; type III oxidants arise on Fe2+ free in solution and probably do not cause killing. Therefore, particular interactions of DNA with transition metals should be considered to be an integral part of the chemistry and toxicity of H2O2.

DNA↗
PubMed1994

Correction of the DNA repair defect in xeroderma pigmentosum group E by injection of a DNA damage-binding protein.

Cells from a subset of patients with the DNA-repair-defective disease xeroderma pigmentosum complementation group E (XP-E) are known to lack a DNA damage-binding (DDB) activity. Purified human DDB protein was injected into XP-E cells to test whether the DNA-repair defect in these cells is caused by a defect in DDB activity. Injected DDB protein stimulated DNA repair to normal levels in those strains that lack the DDB activity but did not stimulate repair in cells from other xeroderma pigmentosum groups or in XP-E cells that contain the activity. These results provide direct evidence that defective DDB activity causes the repair defect in a subset of XP-E patients, which in turn establishes a role for this activity in nucleotide-excision repair in vivo.

Cells, Cultured↗
PubMed1994

Bendectin and birth defects: I. A meta-analysis of the epidemiologic studies.

"Bendectin" (Doxylamine/Dicyclomine/Pyridoxine) was widely used for the treatment of nausea and vomiting of pregnancy until 1983, when production was discontinued in the face of lawsuits alleging that the drug caused congenital malformations. We have conducted a meta-analysis of the 16 cohort and 11 case-control studies that report birth defects from Bendectin-exposed pregnancies. This meta-analysis provides an estimate of the relative risk of malformation at birth in association with Bendectin exposure. The pooled estimate of the relative risk of any malformation at birth in association with exposure to Bendectin in the first trimester was 0.95 (95% Cl 0.88 to 1.04). Separate analyses were undertaken for cardiac defects, central nervous system defects, neural tube defects, limb reductions, oral clefts, and genital tract malformations. In these categories, the pooled estimates of relative risk ranged from 0.81 for oral clefts to 1.11 for limb reductions, with all 95% confidence intervals enclosing unity. With the exception of studies for oral clefts and for pyloric stenosis, tests for heterogeneity of association indicated for each table that all studies were estimating the same odds ratio. These studies, as a group, showed no difference in the risk of birth defects between those infants whose mothers had taken Bendectin during the first trimester of pregnancy and those infants whose mothers had not. It is unlikely that Bendectin exposure contributed to the prevalence of congenital malformations in the population.

Abnormalities, Drug-Induced↗
PubMed1993

Characterization of a human DNA damage binding protein implicated in xeroderma pigmentosum E.

A human DNA damage binding protein implicated in the DNA excision repair disorder xeroderma pigmentosum E was purified to near homogeneity from HeLa cells. The protein is abundant (approximately 10(5) copies/cell) and has a native molecular weight of 154,000-163,000 as estimated by gel filtration and glycerol gradient sedimentation. DNA damage binding activity copurified with polypeptides of 124 and 41 kDa. Based on the native molecular weight, cosedimentation of both polypeptides with DNA damage binding activity on glycerol gradients, and a molar ratio of approximately 1:1 for the two polypeptides, it appears that p124 and p41 are subunits of a heterodimeric protein. Binding to damaged DNA was resistant to K+ concentrations approaching 1 M, but showed anion-specific sensitivity to Cl- concentrations above 0.5 M, suggesting that the majority of the binding energy is contributed by nonionic interactions. In contrast to previous reports, the DNA damage binding protein was shown to recognize cyclobutane pyrimidine dimers in addition to a nonphotoreactivable lesion(s), most likely the pyrimidine-pyrimidone (6-4) photoproduct.

Chromatography, Gel↗
PubMed1993

Comparative analysis of binding of human damaged DNA-binding protein (XPE) and Escherichia coli damage recognition protein (UvrA) to the major ultraviolet photoproducts: T[c,s]T, T[t,s]T, T[6-4]T, and T[Dewar]T.

Human cells contain a protein that binds to UV-irradiated DNA with high affinity. This protein, the damaged DNA-binding protein (DDB), is absent from some xeroderma pigmentosum complementation group E cell strains; therefore, it has been suggested that it may be the damage recognition subunit of a human excision nuclease complex. However, the identity of the UV photoproduct bound by DDB and the role of this protein in nucleotide excision repair have been controversial. In this study, we used several synthetic DNA substrates, each of which contains one of the major UV photoproducts, and DDB purified to apparent homogeneity to quantify the specific binding of DDB to various photoproducts. For comparison, the binding of the same photoproducts by the Escherichia coli damage recognition protein UvrA, which is known to be a subunit of the E. coli excision nuclease, was also measured. UvrA and DDB each bound with high affinity to T[t,s]T, T[6-4]T, and T[Dewar]T, but only marginally discriminated between an undamaged oligomer and an oligomer with a T[c,s]T. In contrast to these similarities with regard to the binding to UV photoproducts, UvrA bound to another excision repair substrate, the psoralen-thymine monoadduct, with high specificity, whereas DDB was unable to distinguish between psoralen-adducted DNA and undamaged DNA. We conclude that DDB may play a special role in the repair of UV damage, but it cannot be the sole damage recognition subunit of human excision nuclease.

Adenosine Triphosphatases↗
PubMed1993

Pyknodysostosis: imaging and laboratory observations.

Pyknodysostosis is a rare form of sclerosing bone dysplasia with autosomal recessive inheritance. Affected members of two families were assessed as follows: three patients underwent densitometry measurements and bone scans; four patients underwent magnetic resonance imaging (MRI) and an immunological investigation, as well as a detailed endocrinological and biochemical laboratory review. Densitometry measurements revealed values of up to 291% of age-matched normal controls; this increased bone density was mainly in the trabecular bone and not in the cortical bone. The MRI showed the cortex to be of normal thickness, whereas the increase in trabecular bone limited the space within the medullary canal. Bone scans and single photon emission computerized tomography in three patients showed an increased uptake of [99mTc]methylene diphosphonate of up to 538% of age-matched controls, which reflected the increased bone density. Monocyte function tests demonstrated a normal phagocytic capacity, but their killing activity was impaired. Interleukin-1 secretion was also impaired, which may point to the pathogenesis of the disease, in view of its function as an osteoclast activator and its role in bone resorption.

Adolescent↗
PubMed1993

Injury severity scoring and length of stay in hospital of war casualties--demonstration of an association and possible selection bias.

The Injury Severity Score (ISS) is a widely used measure of anatomical injury. It is the sum of squares of the highest scores on the Abbreviated Injury Scale (AIS) in each of the three most severely injured body regions. This study was designed to describe the relationship between ISS and length of stay (LOS) in hospital. The ISS was independently determined by four physicians who studied 491 war casualties, excluding dead on arrival and non-trauma patients. The study demonstrates non-linear and non-homogeneous relationships between ISS and LOS. Exclusion of fatalities resulted in biased (higher) estimates of LOS among those with ISS scores of 25-66. The patients could be grouped into five categories according to their maximal AIS (MAIS): (1) Slight injury--i.e. those with injuries appropriate for AIS scores 1 or 2 that lead to an LOS of median 5 days; (2) Moderate injury--i.e. those with injuries appropriate to AIS scores of 3, with an expected median LOS of 10 days; (3) Severe injuries--i.e. those with injuries appropriate to AIS scores of 4, with expected median LOS of about 17 days; (4) Very severe injuries--i.e. those with one injury appropriate to an AIS score of 5; and (5) Multiple severe injuries--those who are severely wounded in two or more body regions, i.e. those with two or more injuries appropriate to AIS scores of 5 and 4, with a median LOS of 39 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1993

High-density lipoprotein cholesterol and alcohol consumption in US white and black adults: data from NHANES II.

OBJECTIVES: High-density lipoprotein (HDL) cholesterol is known to be positively related to moderate alcohol consumption from studies in selected populations. This study describes the association in a representative sample of the US adult population. METHODS: Stratification and multivariate regression analyses were used to examine HDL cholesterol levels and alcohol consumption. RESULTS: Fewer women than men reported consumption of alcohol at any frequency. Similar percentages of Whites and Blacks reported alcohol consumption. Age-adjusted mean HDL cholesterol levels were higher among alcohol drinkers than among nondrinkers in all sex-race strata. Mean HDL cholesterol levels of Whites and Blacks of both sexes increased consistently with increased frequency of consumption of beer, wine, and liquor. With age, education, body mass index, smoking, and physical activity controlled for, there were higher age-adjusted HDL cholesterol levels with increasing reported quantities of alcohol consumed. Daily or weekly use of alcohol led to an increase of 5.1 mg/dL in mean HDL cholesterol level, whereas consumption of 1 g of alcohol led to an increase of 0.87 mg/dL. CONCLUSION: Even if there is a causal association between alcohol consumption and higher HDL cholesterol levels, it is suggested that efforts to reduce coronary heart disease risks concentrate on the cessation of smoking and weight control.

Adult↗
PubMed1993

Disability and the years of potential productivity lost: modifying the years of potential life lost and the investment-production-consumer model by disability level.

The full impact and the loss to society from disability are seldom evaluated. We suggest a modification of the years of potential life lost (YPLL) by the overall percentage of permanent disability to obtain estimates of years of potential productivity lost (YPPL). We compare YPPL with the maximal years of potential productivity of an individual by difference and ratio measures. We employ similar methodology to modify valued years of potential life lost (VYPLL) according to the investment-producer-consumer model. We demonstrate the methodology by an example using data on disabled veterans.

Adolescent↗
PubMed1992

Selective immunoneutralization of the multiple activities of Escherichia coli DNA polymerase I supports the model for separate active sites and indicates a complex 5' to 3' exonuclease.

DNA polymerase I (pol I) from Escherichia coli has three well-defined activities: DNA polymerase, 3'-5' exonuclease, and 5'-3' exonuclease. We have raised monoclonal antibodies to pol I which selectively neutralize each of these three activities, thus supporting the model of separate active sites for each activity, heretofore exclusively demonstrated with proteolytic fragments of pol I. Antibodies from each class could bind pol I in the presence of antibodies of another class, indicating the existence of significant spatial separation between each of the three sites. In addition, several of the neutralizing antibodies were able to distinguish particular activities of the 5'-3' exonuclease. One of them, for example, inhibited the RNase H activity but not the DNase activity. Two other antibodies could, in addition to inhibiting the polymerase and the 3'-5' exonuclease, either stimulate or inhibit the 5'-3' exonuclease depending upon the assay conditions, particularly the ionic strength.

Animals↗
PubMed1992

Influence of cumulative sun exposure on the prevalence of common acquired nevi.

BACKGROUND: Conflicting evidence exists on the relation between sun exposure and the number of common acquired nevi. The increase in the number of common acquired nevi until early adulthood and their greater concentration on sun-exposed areas suggested that the growth of common acquired nevi is promoted by UV radiation. Nevertheless, it was noticed that although solar exposure accumulates with age, the number of common acquired nevi decreases after the third decade. OBJECTIVE: Our purpose was to examine the relation between the prevalence of common acquired nevi and accumulative sun exposure. METHODS: The number of common acquired nevi on 128 patients with multiple solar keratoses (SK) was compared with their number on 82 control subjects. The existence of SK served as a biologic marker for long-term solar effects. RESULTS: On patients with SK we counted 1285 nevi (mean 10.0 nevi per person) and on control subjects, 1521 nevi (mean 18.5 nevi) (p = 0.0046; Kruskal-Wallis test). The finding that persons exhibiting signs of accumulating sun effects have fewer nevi was maintained irrespective to differences of gender, occupation, and complexion. CONCLUSION: Our data suggest that accumulating solar effects may contribute to the natural maturation and elimination of common acquired nevi in late adulthood.

Aged↗
PubMed1992

Biochemical heterogeneity in xeroderma pigmentosum complementation group E.

Cells from two patients with xeroderma pigmentosum complementation group E (XP-E) have been shown to lack an activity which binds specifically to UV-irradiated DNA (Chu and Chang, 1988). We investigated the occurrence of this binding activity in cell strains from nine additional, unrelated XP-E patients and found that all but one of these strains contained normal levels of the binding protein. Furthermore, the binding activity from these XP-E strains was indistinguishable from that of normal controls in thermal stability, behavior on ion-exchange chromatography, and electrophoretic mobility of protein-DNA complexes, indicating that there were no gross structural alterations in the protein. The association of XP-E with a deficiency in DNA-damage binding protein in cells from 3 of 12 XP-E patients (compared to 0 of 20 non-XP-E controls) is statistically significant (p less than 0.05), but there is no obvious correlation between the biochemical defect and the clinical or cellular characteristics of individual patients. Implications of these findings for the role of the binding protein in XP-E are discussed.

Cells, Cultured↗
PubMed1992

DNA polymerase I modulates inducible stable DNA replication in Escherichia coli.

Mutants of Escherichia coli lacking RNase HI activity and cells induced for the SOS response express modes of DNA replication independent of protein synthesis, called constitutive and induced stable DNA replication, respectively. We report here that mutants deleted for the polA gene express induced stable DNA replication at approximately 25-fold the rate of wild-type cells, whereas constitutive stable DNA replication is not enhanced.

DNA Polymerase I↗