Improved single-strand DNA sizing accuracy in capillary electrophoresis

Interpolation algorithms can be developed to size unknown single-stranded (ss) DNA fragments based on their electrophoretic mobilities, when they are compared with the mobilities of standard fragments of known sizes; however, sequence-specific anomalous electrophoretic migration can affect the accuracy and precision of the called sizes of the fragments. We used the anomalous migration of ssDNA fragments to optimize denaturation conditions for capillary electrophoresis. The capillary electrophoretic system uses a refillable polymer that both coats the capillary wall to suppress electro-osmotic flow and acts as the sieving matrix. The addition of 8 M urea to the polymer solution, as in slab gel electrophoresis, is insufficient to fully denature some anomalously migrating ssDNA fragments in this capillary electrophoresis system. The sizing accuracy of these fragments is significantly improved by the addition of 2-pyrrolidinone, or increased capillary temperature (60 degrees C). the effect of these two denaturing strategies is additive, and the best accuracy and precision in sizing results are obtained with a combination of chemical and thermal denaturation.

Adult obesity and functioning in the family of origin

OBJECTIVE

This study investigated the relationship between eating and weight behaviors and functioning in individuals' families of origin.

METHOD

Subjects were 237 women and 242 men enrolled in the RENO (Relationship of Energy, Nutrition, and Obesity) Diet-Heart Study, a prospective 5-year study of the effects of weight fluctuation on cardiovascular disease risk factors in normal weight and obese adults. Variables of primary interest included subjects' body mass index (BMI), age of onset of obesity, eating attitudes, lack of control while eating, and family functioning.

RESULTS

In men, higher family cohesion was related to healthier eating attitudes and better control over eating, controlling for age, BMI, and adaptability, whereas higher adaptability (changing rules and poor leadership) was related to earlier onset of obesity and more disturbed eating attitudes. Cohesion and adaptability were not related to body weight or eating variables in women.

DISCUSSION

The lower societal pressure on men to be thin may increase the importance of family factors in influencing their shape and weight.

Thalidomide and thalidomide analogs reduce HIV type 1 replication in human macrophages in vitro

Thalidomide is currently being evaluated for efficacy in alleviating some manifestations of HIV-1 infection. To determine whether thalidomide has any direct effects on HIV-1 infection, we investigated the effect of thalidomide and also of three structural analogs of thalidomide on HIV-1 replication in vitro in human monocyte-derived macrophages. The thalidomide analogs were previously shown to inhibit TNF-alpha production in vitro at much lower concentrations than thalidomide. In HIV-1-infected macrophages treated with thalidomide or thalidomide analogs, viral replication was reduced by 60 to 80% as determined by measuring viral RT activity in the culture supernatants. In all experiments the analogs inhibited HIV-1 replication more efficiently than did thalidomide. The drugs also reduced HIV-1 gag mRNA expression. Furthermore, the drugs caused a decrease in NF-kappaB-binding activity in nuclear extracts of HIV-1-infected macrophages. The role of NF-kappaB in the drug-induced inhibition of HIV-1 replication was confirmed using an NF-kappaB-defective mutant virus to infect macrophages.

How Do Logical Inference Rules Help Construct Social Mental Models?

Starting from recent approaches in mental model research, it is argued that (1) logical inference rules are used in order to construct mental cliques from learned sentiment relations, and (2) social context cues (operationalized as primes) play a crucial role in activating such rules. Transitivity and antitransitivity are taken as examples, and are shown as core constituents of such models. In a first experiment, priming was achieved by announcing the sorting of fictitious persons in either two or three cliques. Thirty-one subjects studied eight sets of sentiment relations among these persons that either did or did not satisfy their primed clique expectations. They showed longer study times and more requests for additional information in the case of inconsistent fits between prime and set. Their sorting solutions also showed clear priming effects. A second experiment (n = 30) showed that when undergoing a recognition test after seeing the relation sets, subjects tended to confuse model-consistent distractors with information they had actually seen. In a third experiment (n = 30) the results from Experiment 1 were replicated using more realistic learning materials.

Extending the Benefits of Recategorization: Evaluations, Self-Disclosure, and Helping

The Common Ingroup Identity Model proposes that if members of different groups conceive of themselves more as a single group rather than as two separate groups, intergroup bias will be reduced through processes involving pro-ingroup favoritism. The present research extended work on this model by investigating the effects of recategorization on intergroup behavior, specifically helping and self-disclosure, as well as evaluations. Participants first worked as members of two three-person groups, and then the two groups interacted under conditions designed to enhance a two-group representation or recategorization with an inclusive one-group representation. As expected, the manipulation of the intergroup contact situation that created stronger impressions of one group reduced intergroup bias in evaluations, self-disclosure, and helping. Furthermore, ratings of the extent to which the six participants felt like one group mediated the reduction in bias, particularly for evaluative bias. Conditions facilitating the generalization of the benefits of recategorization to group members not present and to other groups are considered.

The experience of thought-disordered individuals preceding an aggressive incident

The purpose of this qualitative study was to increase the understanding of the experiences of individuals with thought disorders, which precede incidents of aggression. Twelve individuals, from two hospitals, who had a nursing diagnosis of thought disorder and a history of aggression were interviewed, between one and four times, to collect baseline information and information about particular aggressive incidents. The participants described in their own words their thoughts, feelings and experiences preceding the aggressive incidents. Three themes emerged. First, participants perceived themselves to be strongly affected by the external environment; their responses to aspects of the environment were influential in precipitating the aggressive incident. Second, participants perceived themselves, paradoxically, to be both powerful and powerless; the act of aggression becomes an incident of brief self-empowerment. Third, the aggressive incident occurred in spite of the participants' acknowledgement and previous use of anger-controlling strategies; the participants' perceptions of themselves as powerless in an oppressive environment may have mitigated against the success of these strategies. Nurses need to know what triggers aggressiveness in psychiatric patients, in order to intervene effectively. Mental health professionals must also reexamine the psychiatric hospital environment, to make sure they are not needlessly exacerbating their patients' powerlessness with policies that are unjustifiably controlling.

Efficacy of electrical stimulation at frequencies higher than basal rate in canine stomach

The optimum frequency for electrically stimulating motility in the stomach is still in question. Some studies of gastric electrical stimulation (GES) at near physiologic frequencies have reported gastric electrical entrainment but with little efficacy in improving motility. In this study we examined the effectiveness of electrical stimulation at a broad range of frequencies in entraining gastric electrical activity (GEA) and eliciting contractions in a canine model. The stomachs of six dogs, each implanted with four pairs of stainless steel electrodes and two strain gauges were stimulated at frequencies ranging from 3 to 30 cycles/min. GEA and contractions were monitored before and during electrical stimulation. The ability of GES at different frequencies to reverse the effect of glucagon was also investigated. GEA was entrained in most animals at frequencies close to the intrinsic rate as well as at four to five times the intrinsic rate. At other stimulation frequencies, the recorded electrical control activity either remained unchanged, uncoupled, or became dysrhythmic. Contractile response to stimulation at four to five times the intrinsic rate were significantly higher than those at frequencies close to the intrinsic rate (P < 0.05). GES did not alter the effect of glucagon. Stimulation at a frequency of four times the basal rate of 5/min elicited the largest motility index in dogs. Stimulation at frequencies much higher than the physiologic rate warrants further study as a possible optimum range for GES.

The needs of parents of pediatric oncology patients during the palliative care phase

The death of a child is considered one of the greatest stresses a parent can experience. It has been suggested that death from childhood malignancies is more stressful for parents than death due to other chronic diseases. The purpose of this qualitative study is to identify parents' perceptions of their needs while their child was dying of cancer. Twelve parents of eight children, who died of various types of cancer 1 to 3 years ago, were interviewed by the primary investigator. These children died either in hospital or at home. Interviews were tape recorded, transcribed and analyzed by the investigators. Three needs were identified: (1) The need to have the child recognized as special while retaining as much normality within the child's and family's lives as possible; (2) The need for caring and connectedness with health care professionals; and (3) The need to retain responsibility of parenting their dying child. Findings suggest that parental needs are similar regardless of where the death occurred. Implications for nursing practice and areas for further research were identified.

Determinants of vaginal-perineal integrity and pelvic floor functioning in childbirth

OBJECTIVES

Our purpose was to evaluate risk factors for severe vaginal-perineal trauma and to ascertain determinants of pelvic floor strength.

STUDY DESIGN

Secondary analysis of 459 nulliparous women enrolled in a randomized controlled trial of episiotomy was carried out. In a multivariate analysis we examined the association between (1) sulcus tears, (2) third- or fourth-degree tears, and (3) pelvic floor strength and selected demographic, physiologic, pregnancy-related, and intrapartum factors.

RESULTS

Unemployment and shorter second stage of labor were significant predictors of sulcus tears. Episiotomy, forceps use, and birth weight were important predictors of third- and fourth-degree tears. Whereas perineal intactness (use of episiotomy and spontaneous tears) was not influenced by exercise, a strong exercise profile was associated with fewer third- and fourth-degree tears in the presence of episiotomy. Exercise did not influence the rate of sulcus tears. A total of 35% of the variability in postpartum pelvic floor strength was explained by antepartum strength; however, we were only able to identify 5% of the factors contributing to antepartum pelvic floor strength.

CONCLUSIONS

Determinants of sulcus tears appear to be present before pregnancy; third- and fourth-degree tears are related to physician management. Exercise mitigates the potential for severe trauma induced by episiotomy.

Pleistocene geochronology and palaeothermometry from protein diagenesis in ostrich eggshells: implications for the evolution of modern humans

Proteinaceous residues incorporated within the crystal structure of ostrich eggshells (OES) are retained without loss over geological time exceeding 10 million years. Degradation of the polypeptides, including hydrolysis to smaller peptide fragments and eventual release of free amino acids, decomposition, and racemization and epimerization occur at regular, predictable rates dependent on ambient temperature. The extent of isoleucine epimerization (alle/Ile ratio) in OES follows linear first-order reversible kinetics in controlled-temperature laboratory simulations of time up to an alle/Ile ratio in excess of 1.0. The hydrolysis of leucine also follows a predictable pattern, but deviates from first-order kinetics. A nonlinear mathematical model has been developed that adequately describes the pattern of leucine hydrolysis through a wide temperature range. Arrhenius parameters were derived from laboratory experiments combined with rate constant values found for 14 C-dated OES from stratified caves in southern Africa. These parameters for isoleucine epimerization and leucine hydrolysis differ by ca . 10%, allowing the simultaneous solution of the two equations for temperature, independent of sample age. Although the uncertainty of the simultaneous temperature is relatively high (± 10°C), it provides an effective means of identifying burned samples. If sample age is known, palaeotemperatures (the integrated thermal history experienced by an eggshell as opposed to an ‘instantaneous’ temperature) can be calculated with a precision of better than ± 1°C. The ages of levels at Border Cave, South Africa, from which anatomically modern human skeletal remains have been recovered, are dated by the extent of isoleucine epimerization in associated OES. The reaction is calibrated in the upper levels by a series of concordant radiocarbon dates on charcoal at 38 ka before present (BP). The amino acid dates on deeper levels indicate that the Howiesons Poort stratum at Border Cave is more than 70 ka old, and that anatomically modern humans occupied the site as early as 100 ka ago.

Combined finasteride and flutamide therapy in men with advanced prostate cancer

OBJECTIVES

To evaluate the efficacy of combined finasteride and flutamide therapy in men with advanced prostate cancer by determining (1) the short-term tolerability of finasteride monotherapy and its effect on serum prostate-specific antigen (PSA) and hormone (testosterone, dihydrotestosterone) levels, and (2) the effects of the addition of flutamide on tolerability and on serum PSA and hormone levels.

METHODS

Thirteen hormone-naive men with advanced prostate cancer (4 with Stage D2, 1 with Stage D1, 1 with Stage D0, and 7 with rising PSA levels after radical prostatectomy [n = 2] or definitive radiation therapy [n = 5]) were initially treated with 5 mg finasteride daily. Flutamide (250 mg three times a day) was added after serum PSA levels stabilized.

RESULTS

Finasteride alone (median 5 weeks) had no significant effect on serum PSA levels (P > 0.05). Combined finasteride and flutamide resulted in a mean 91% reduction in serum PSA levels, with 85% of men achieving a nadir serum PSA level of less than 4.0 ng/mL and 46% achieving undetectable levels (0.2 ng/mL or less). Finasteride alone had no significant effect on serum testosterone levels (P > 0.05) but did result in a mean 74% reduction in serum dihydrotestosterone levels. Combined finasteride and flutamide resulted in a mean 56% increase in serum testosterone levels but had no additional effect on serum dihydrotestosterone levels (P > 0.05). Side effects occurred in 85% (gynecomastia or breast tenderness in 62% [8 of 13] and diarrhea in 23% [3 of 13]) of men on combined therapy. Potency was preserved in 66%. Combined finasteride and flutamide therapy was withdrawn from 15% (2 of 13) because of flutamide-induced diarrhea and from 23% (3 of 13) because of disease progression. All remaining patients (8 of 13) have serum PSA levels below 4.0 ng/mL and 4 of these 8 have undetectable levels. These men have received combined finasteride and flutamide for a median 11 months (range 6 to 19).

CONCLUSIONS

Finasteride monotherapy is inadequate therapy for advanced prostate cancer, but combined finasteride and flutamide may be a reasonable alternative for men with advanced prostate cancer who refuse conventional hormone therapy.

IL-1 beta stimulates superoxide and delayed peroxynitrite production by pulmonary vascular smooth muscle cells

Our previous studies have shown that rat pulmonary microvascular smooth muscle cells (RPMSMC) upregulate inducible nitric oxide synthase (iNOS) and produce nitric oxide (NO) when treated with interleukin-1 beta (IL-1 beta). We now report that an additional effect of IL-1 beta stimulation in RPMSMC is an increase in production of superoxide (O2-) that results in the formation of peroxynitrite (ONOO-). IL-1 beta produced a rapid (within 1 h) concentration-dependent increase in O2-, as detected by ferricytochrome c reduction and lucigenin-enhanced chemiluminescence. O2- production was sensitive to quinacrine and diphenyliodinium, suggesting that NADH and NADPH oxidoreductases were responsible. After induction of iNOS and production of iNOS-derived NO, ONOO- was detected by luminol-enhanced chemiluminescence and was found to cause lipid peroxidation and to form nitrotyrosine in the cytoskeleton, detected by immunostaining. Cell viability, however, appeared to be unaffected. IL-1 beta-mediated induction of RPMSMC-derived ONOO- may have significant effects on pulmonary vascular function in sepsis and inflammatory states.

Glycine regulation of synaptic NMDA receptors in hippocampal neurons

1. Although glycine has been identified as a required coagonist with glutamate at N-methyl-D-aspartate (NMDA) receptors, the understanding of glycine's role in excitatory synaptic neurotransmission is quite limited. In the present study, we used the whole cell patch-clamp technique to examine the ability of glycine to regulate current flow through synaptic NMDA receptors at excitatory synapses between cultured hippocampal neurons and in acutely isolated hippocampal slices. 2. These studies demonstrate that the glycine modulatory site on the synaptic NMDA receptor is not saturated under baseline conditions and that increased glycine concentrations can markedly increased NMDA-receptor-mediated excitatory postsynaptic currents (EPSCs) in hippocampal neurons in both dissociated cell culture and in slice. Saturation of the maximal effect of glycine takes place at different concentrations for different cells in culture, suggesting the presence of heterogenous NMDA receptor subunit compositions. 3. Bath-applied glycine had no effect on the time course of EPSCs in either brain slice or culture, indicating that desensitization of the NMDA receptor is not prevented by glycine over the time course of an EPSC. 4. When extracellular glycine concentration is high, all miniature EPSCs recorded in the cultured hippocampal neurons contained NMDA components, indicating that segregation of non-NMDA receptors at individual synaptic boutons does not occur.

High-speed exercise history and catastrophic racing fracture in thoroughbreds

OBJECTIVE

To investigate the relation between several racing speed history characteristics and risk of fatal skeletal injury (FSI) in racing Thoroughbreds.

ANIMALS

64 Thoroughbreds euthanatized during a 9-month period in 1991 at a California racemeet because of a catastrophic fracture incurred while racing (cases), identified retrospectively. For each race in which an FSI occurred, 1 control horse was randomly selected from the noncatastrophically injured participants.

PROCEDURE

Racing and officially timed workout histories were obtained for each horse. Several history characteristics were calculated to summarize racing career patterns and high-speed exercise schedules prior to date of injury and included age at first race, proportion of career spent laid up, average duration of laid up periods, average lifetime racing frequency, time from last lay up to date of injury, and total and rate of distance accumulated 1 to 6 months prior to date of injury. History characteristics associated with FSI were screened by paired t-test and studied in detail, using conditional logistic regression.

RESULTS

High total and high average daily rates of exercise distance accumulation within a 2-month period were associated with higher risks for FSI during racing, yet career patterns, such as age at first race or total proportion of career spent laid up, were not found to be associated with risk for FSI. A horse that had accumulated a total of 35 furlongs of race and timed-work distance in 2 months, compared with a horse with 25 furlongs accumulated, had an estimated 3.9-fold increase in risk for racing-related FSI (95% confidence interval = 2.1, 7.1). A horse that had accumulated race and timed-work furlongs at an average rate of 0.6 furlong/d within a 2-month period, compared with a horse with an average of 0.5 furlong/d, had an estimated 1.8-fold increase in risk for racing-related FSI (95% confidence interval = 1.4, 2.6).

CONCLUSIONS AND CLINICAL RELEVANCE

Thoroughbred racehorses that either accumulate large total high-speed distances or rapidly accumulate high-speed distances within a 2-month period may be at increased risk for FSI during racing.

Flowable networks as DNA sequencing media in capillary columns

A novel class of materials that self-assemble in water into equilibrium network structures with a well-defined mesh size consist of polyethylene glycols (PEG's) end-capped with micelle-forming fluorocarbon tails. These micellar systems form flowable aqueous gel-like networks that permit electrophoretic DNA sequencing in capillary columns. The gels have unusual rheological properties, including network breakdown under shear, resulting in plug flow that allows columns refill with complete ejection of byproducts of the previous sequencing analysis. In this system, DNA fragment electrophoretic mobilities are unaffected by the hydrophobicity of the polymer tails. Low molecular weight (M) PEG chains (M 8000) show catastrophic resolution loss for DNA fragments larger than 100 bases due to band broadening. For a longer PEG segment (M 35000) separating the end groups, band broadening occurs for DNA fragments larger than 300 bases, implying that the PEG segment length controls the mesh size in the equilibrium network structure. Optimum sequencing results were obtained from a 6% solution of a 1:1 mixture of C6F13 end-capped- and C8F17 end-capped PEG 35,000. The resolution limit of fluorescent-dye-labeled sequencing products in this formulation was 450 bases in 75 microns capillaries at 200 V/cm.

Quantitative EEG differences in a nonclinical sample of children with ADHD and undifferentiated ADD

OBJECTIVE

To use quantitative electroencephalographic (EEG) techniques to identify electrophysiological differences between children with distinct disorders of attention and/or hyperactivity.

METHOD

Forty children from a prescreened community sample were evaluated by means of both spectral EEG and evoked response potential (ERP) techniques. The children were 7 to 13 years of age and were selected on the basis of membership in one of the following DSM-III-R categories: attention-deficit hyperactivity disorder (ADHD) (n = 16), undifferentiated attention deficit disorder (UADD) (n = 12), or no disruptive disorder diagnosis (n = 12).

RESULTS

Spectral EEG revealed that UADD subjects had less delta band relative percent power (RPP) (p < .01), more beta band RPP (p < .01), and ERP findings of a decreased rare tone P300 amplitude (p < .02) compared with the control group. ADHD subjects had spectral EEG findings of increased beta band RPP (p < .05) and ERP findings of an increased common tone N100 latency (p < .02) and a decreased rare tone P300 amplitude (p < .02). Interhemispheric asymmetries appeared to distinguish the groups: the UADD group had spectral EEG asymmetries; the ADHD group had only ERP asymmetries; and the control group had no asymmetries.

CONCLUSION

Quantitative EEG techniques may prove useful in differentiating specific subtypes of ADHD.