Internet use 101 in college: Do undergraduates want to learn healthier internet use?

Background: Internet overuse is an emerging public health emergency, especially for college students in the United States. The purpose of this study was to assess college students' internet usage and interest in learning healthy internet usage skills as part of a college curriculum. Study design: Participants completed an online anonymous questionnaire which included the short version of the Internet Addiction Test, a modified Youth Health Movement survey, and questions regarding their interest in healthy internet use coursework. Methods: A total of 402 participants were recruited via an email LISTSERV of current undergraduates and recent graduates who had taken at least one class within a child and adolescent mental health studies minor while enrolled in a large university. Results: Overall, 70% of participants reported that they use the internet excessively, and a majority of participants reported that internet use has negatively affected their sleep and increased their anxiety. Seventy percent of participants reported that they would benefit from instruction on healthy internet usage via formal courses for credit or online modules. Conclusions: Students are aware of the difficulty in managing their internet use in college and are motivated to engage in novel courses on healthy internet usage. Academic institutions should consider developing courses or modules on healthy internet use.

Clonal evolution in a human neuroblastoma.

Tumor samples, obtained from a single patient at two points in his illness, have enabled us to study clonal evolution in a neuroblastoma. Cells from the primary tumor demonstrated considerable heterogeneity in terms of chromosome number; cells from 4 subsequent metastases were all nearly diploid; and cells from a tumor produced in a mouse by the injection of cells from the primary tumor were hypotriploid in modal number. All of the tumor samples contained the same marker chromosome rearrangements, indicating their origin from a common precursor. Each of the cell lines analyzed (including those from the patient's metastases, those from the tumor in a mouse, and those from the primary tumor after 11 months in continuous culture) also contained different and distinguishing chromosome abnormalities. The differences in karyotype among these tumor samples and cell lines presumably reflect the different selection pressures at work in each instance.

Human neuroblastomas and abnormalities of chromosomes 1 and 17.

Structural rearrangements of chromosome 1p have been reported previously as a frequent finding in human neuroblastomas. In a review of karyotypes from 35 neuroblastomas (including 29 published cases and 6 unpublished tumors and cell lines), it was found that, in addition to the abnormalities of chromosome 1p (found in approximately 70% of cases), abnormalities involving only 2 other chromosome segments occurred with significant frequency (in 20% or more of cases) in this cancer. These abnormalities involved trisomies for the long arms of chromosomes 1 and 17. In addition, two novel cytogenetic aberrations, homogeneously staining regions and double minutes, were identified in two-thirds of the cases. It is postulated that the gene change(s) produced by the abnormalities of chromosome 1p in neuroblastoma play a primary role in the development of this cancer. The gene changes produced by the abnormalities of chromosomes 1q and 17q and by the homogeneously staining regions and double minutes are presumed to contribute to tumor progression.

Recovery in geriatric depression.

BACKGROUND: Clinical characteristics of depression, age at illness onset, medical burden, disability, cognitive impairment, lack of social support, and poor living conditions may influence the course of depression. This study investigates the timetable of recovery and the role of the above factors in predicting recovery in elderly patients with major depression. METHODS: Recovery was studied in 63 elderly (age >63 years) and 23 younger patients with depression who were followed up for an average of 18.2 months (SD, 13.1 months) under naturalistic treatment conditions. Diagnosis was assigned according to Research Diagnostic Criteria after administration of the Schedule for Affective Disorders and Schizophrenia. The Longitudinal Follow-up Interval Examination was used to identify recovery. RESULTS: The recovery rate of depressed elderly patients was similar to that of younger depressed patients. In the elderly patients, age, antidepressant treatment, age at onset, and chronicity of episode were significantly associated with time to recovery since entry. Among these parameters, late age at onset was the strongest predictor of slow recovery. In younger patients, long time to recovery was predicted by weak social support, younger age, cognitive impairment, and low intensity of antidepressant treatment. In the elderly, the intensity of antidepressant treatment began to decline within 16 weeks from entry and approximately 10 weeks prior to recovery. CONCLUSIONS: These findings challenge the view that geriatric depression has a worse outcome than depression in younger adults. However, depressed patients with onset of first episode in late life may be at higher risk for chronicity. Antidepressant treatment prescribed by clinicians may decline prior to recovery despite evidence that high treatment intensity is effective in preventing relapse.

Relationship between Tetracyclines' Structure and Minimal Inhibitory Concentration of Streptococcus spp.

During the past years, a growing number of bacterial strains have become resistant to tetracyclines. The problem of increasing resistance and lack of susceptibility to tetracyclines applies to strains isolated from both: animals and humans. Basic tools to design new drugs and determining the direction of the search for new molecules is the analysis of the relationship between the chemical structure and the pharmacokinetic and pharmacodynamic parameters. Purpose of this study is to determine the relationship between physicochemical parameters of tetracyclines and MIC50 and MIC90 values determined for Streptococcus spp. Analysis of physicochemical parameters of selected drugs was made using MarvinSketch 5.11.5 (ChemAxon Ltd.) and QuickProp 3.1 software from Schrödinger package v 31207. MIC50 and MIC90 values were correlated with 51 calculated physicochemical parameters and arithmetic expressions. Internal and external model validation was performed using leave-one out method. 4 arithmetic expressions fulfilled all validation criteria, but only in relation to MIC50. A new method to optimize the tetracyclines' structure in relation to Streptococcus spp. was presented. It was also shown that the relations of structure: antimicrobial activity type can have different nature depending on MIC50 or MIC90 of specific bacterial strain.

mRNA:guanine-N7 cap methyltransferases: identification of novel members of the family, evolutionary analysis, homology modeling, and analysis of sequence-structure-function relationships.

BACKGROUND: The 5'-terminal cap structure plays an important role in many aspects of mRNA metabolism. Capping enzymes encoded by viruses and pathogenic fungi are attractive targets for specific inhibitors. There is a large body of experimental data on viral and cellular methyltransferases (MTases) that carry out guanine-N7 (cap 0) methylation, including results of extensive mutagenesis. However, a crystal structure is not available and cap 0 MTases are too diverged from other MTases of known structure to allow straightforward homology-based interpretation of these data. RESULTS: We report a 3D model of cap 0 MTase, developed using sequence-to-structure threading and comparative modeling based on coordinates of the glycine N-methyltransferase. Analysis of the predicted structural features in the phylogenetic context of the cap 0 MTase family allows us to rationalize most of the experimental data available and to propose potential binding sites. We identified a case of correlated mutations in the cofactor-binding site of viral MTases that may be important for the rational drug design. Furthermore, database searches and phylogenetic analysis revealed a novel subfamily of hypothetical MTases from plants, distinct from "orthodox" cap 0 MTases. CONCLUSIONS: Computational methods were used to infer the evolutionary relationships and predict the structure of Eukaryotic cap MTase. Identification of novel cap MTase homologs suggests candidates for cloning and biochemical characterization, while the structural model will be useful in designing new experiments to better understand the molecular function of cap MTases.

Overcoming cytoplasmic incompatibility in Drosophila.

The endocellular microbe Wolbachia pipientis infects a wide variety of invertebrate species, in which its presence is closely linked to a form of reproductive failure termed cytoplasmic incompatibility (CI). CI renders infected males unable to father offspring when mated to uninfected females. Because CI can dramatically affect fitness in natural populations, mechanisms that abate CI can have equally large impacts on fitness. We have discovered that repeated copulation by Wolbachia-infected male Drosophila simulans significantly diminishes CI. Repeated copulation does not prevent Wolbachia from populating developing spermatids, but may reduce the time during spermatogenesis when Wolbachia can express CI. This restoration of fertility in premated infected males could have important implications for Wolbachia transmission and persistence in nature and for its exploitation as an agent of biological pest control.

Ecological and evolutionary physiology of heat shock proteins and the stress response in Drosophila: complementary insights from genetic engineering and natural variation.

Classical adaptational and genetic engineering approaches offer complementary insights to understanding biological variation: the former elucidates the origins, magnitude and ecological context of natural variation, while the latter establishes which genes can underlie natural variation. Studies of the stress or heat shock response in Drosophila illustrate this point. At the cellular level, heat shock proteins (Hsps) function as molecular chaperones, minimizing aggregation of peptides in non-native conformations. To understand the adaptive significance of Hsps, we have characterized thermal stress that Drosophila experience in nature, which can be substantial. We used these findings to design ecologically relevant experiments with engineered Drosophila strains generated by unequal site-specific homologous recombination; these strains differ in hsp70 copy number but share sites of transgene integration. hsp70 copy number markedly affects Hsp70 levels in intact Drosophila, and strains with extra hsp70 copies exhibit corresponding differences in inducible thermotolerance and reactivation of a key enzyme after thermal stress. Elevated Hsp70 levels, however, are not without penalty; these levels retard growth and increase mortality. Transgenic variation in hsp70 copy number has counterparts in nature: isofemale lines from nature vary significantly in Hsp70 expression, and this variation is also correlated with both inducible thermotolerance and mortality in the absence of stress.

Deleterious consequences of Hsp70 overexpression in Drosophila melanogaster larvae.

We compared transgenic Drosophila larvae varying in hsp70 copy number to assess the consequences of Hsp70 overexpression for growth and development after heat shock. Exposure to a mildly elevated temperature (36 degrees C) induced expression of Hsp70 (and presumably other heat shock proteins) and improved tolerance of more severe heat stress, 38.5-39.5 degrees C. We examined this pattern in two independently derived pairs of extra-copy and excision strains that differed primarily in hsp70 copy number (with 22 and 10 copies, respectively). Extra-copy larvae produced more Hsp70 in response to high temperature than did excision larvae, but surpassed the excision strain in survival only immediately after thermal stress. Excision larvae survived to adulthood at higher proportions than did extra-copy larvae and grew more rapidly after thermal stress. Furthermore, multiple pretreatment reduced survival of 1st-instar extra-copy larvae, but did not affect the corresponding excision strain. While extra Hsp70 provides additional protection against the immediate damage from heat stress, abnormally high concentrations can decrease growth, development and survival to adulthood.

Changes in thermotolerance and Hsp70 expression with domestication in Drosophila melanogaster.

To examine how the duration of laboratory domestication may affect Drosophila stocks used in studies of thermotolerance, we measured expression of the inducible heat-shock protein Hsp70 and survival after heat shock in D. melanogaster strains recently collected from nature and maintained in laboratory culture for up to 50 or more generations. After an initial increase in both Hsp70 expression and thermotolerance immediately after transfer to laboratory medium, both traits remained fairly constant over time and variation among strains persisted through laboratory domestication. Furthermore, variation in heat tolerance and Hsp70 expression did not correlate with the length of time populations evolved in the laboratory. Therefore, while environmental variation likely contributed most to early shifts in strain tolerance and Hsp70 expression, other population parameters, for example genetic drift, inbreeding, and selection likely affected these traits little. As long as populations are maintained with large numbers of individuals, the culture of insects in the laboratory may have little effect on the tolerance of different strains to thermal stress.

A 2p;11q chromosome translocation in dysmyelopoietic preleukemia.

Three patients with dysmyelopoietic preleukemia had a marrow clone with translocation t(2;11)(p21;q23) as the only chromosome change. In one patient, the cytogenetically altered cells disappeared following treatment with 13-cis-retinoic acid. Although these patients did not constitute a homogeneous clinical subgroup, the 2p;11q translocation should probably be added to the short list of nonrandom karyotypic alterations involving 11q23 that have been described in various hematopoietic disorders.

Preleukemia and leukemia with 12p- and 19q+ chromosome alterations following Alkeran therapy.

Among 20 patients with acute nonlymphocytic leukemia or dysmyelopoietic preleukemia secondary to Alkeran therapy for another tumor, four had a del(12)(p11-p12) and four had a translocation to 19q13 among multiple karyotypic alterations in their neoplastic hematopoetic clones. It is suggested that these two cytogenetic abnormalities may occur nonrandomly in such hemic disorders and may play a limited role in their pathogenesis.

Detection of aneuploidy in interphase nuclei from non-small cell lung carcinomas by fluorescence in situ hybridization using chromosome-specific repetitive DNA probes.

Interphase fluorescence in situ hybridization (FISH) is particularly useful for detecting chromosome changes in tumors exhibiting a low mitotic index, as is the case in many human non-small cell lung carcinomas (NSCLCs). A panel of centromeric DNA probes specific for the autosomes 6, 7, 8, 9, 12, 17, and 18 was used to analyze 17 primary NSCLCs. Evidence for aneuploidy was obtained in all specimens. Gain of part or all of chromosome 7 was especially prominent, occurring in a large population of cells in each of 14 tumors (82%). Extra centromeric copies of chromosomes 6, 12, and 17 were also common, being observed in 9 to 11 cases each. Gain of chromosome 9 was infrequent (three tumors). In two cases, most of the nuclei had only a single chromosome 9 fluorescent signal. Karyotypic findings were available for six cases and were generally consistent with the FISH data. Both methods revealed considerable heterogeneity within individual tumors. NSCLC specimens from 26 males were assayed with a Y-specific centromeric sequence; loss of the Y was observed in 13 cases (50%). These investigations demonstrate the feasibility of interphase FISH for the successful analysis of numerical chromosome changes in NSCLCs.

Clinical relevance of chromosome abnormalities in non-small cell lung cancer.

The relationship between clonal chromosome alterations and various clinical parameters was evaluated in 70 patients with non-small cell lung cancer (NSCLC) for whom detailed karyotypic assessment was possible. Included in the analysis are karyotypes of 63 previously published cases and seven new NSCLCs. Clinical features investigated were diagnosis, tumor stage and grade, gender, smoking history measured in pack years, and survival. Certain chromosome abnormalities were significantly associated with histologic subtype, tumor grade, stage, and prognosis. Rearrangements involving chromosome arms 2p and 3q were more common in squamous cell carcinoma (SCC) than in adenocarcinoma (ADC). Loss of 3p was observed more often in SCC. Gain of 7p was more frequent in ADC. Rearrangement of 17p was associated with a lower tumor grade. Rearrangement of Xp and loss of chromosome 12 or 22 were each associated with higher tumor stage. Rearrangement of 3p or 6q was correlated with a better survival outlook. In contrast, loss of chromosomes 4 or 22 portended a poor prognosis. Finally, an increased number of marker chromosomes was observed in patients having a higher number of pack years. These data indicate that chromosome abnormalities can have clinical and pathologic significance in NSCLC.

Advances in the analysis of chromosome alterations in human lung carcinomas.

A review of chromosomal analyses of human lung carcinomas is presented. Karyotypic studies have revealed multiple cytogenetic changes in most small cell lung carcinomas (SCLCs) and non-small cell lung carcinomas (NSCLCs). In SCLCs, losses from 3p, 5q, 13q, and 17p predominate; double minutes associated with amplification of members of the MYC oncogene family may be common late in disease. In NSCLCs, deletions of 3p, 9p, and 17p, +7, i(5)(p10), and i(8)(q10) often are reported. The recurrent deletions encompass sites of tumor suppressor genes commonly inactivated in lung carcinomas, such as CDKN2 (9p21), RB1 (13q14), and TP53 (17p13). Despite technical advances in cell culture, the rate of successful karyotypic analysis of lung carcinomas has remained low. Alternative molecular cytogenetic methods to assess chromosome changes in lung cancer, particularly comparative genomic hybridization (CGH) analysis, are discussed. Initial CGH studies confirm the existence of many of the karyotypic imbalances identified earlier in lung cancer and have revealed several recurrent abnormalities, such as 10q- in SCLC, that had not been recognized previously. The further application of such molecular cytogenetic approaches should enable investigators to define more precisely the spectrum and clinical implications of chromosome alterations in lung cancer.

Natural hyperthermia and expression of the heat shock protein Hsp70 affect developmental abnormalities in Drosophila melanogaster.

We demonstrate that natural heat stress on wild larval Drosophila melanogaster results in severe developmental defects in >10% of eclosing adults, and that increased copy number of the gene encoding the major inducible heat shock protein of D. melanogaster, Hsp70, is sufficient to reduce the incidence of such abnormalities. Specifically, non-adult D. melanogaster inhabiting necrotic fruit experienced severe, often lethal heat stress in natural settings. Adult flies eclosing from wild larvae that had survived natural heat stress exhibited severe developmental anomalies of wing and abdominal morphology, which should dramatically affect fitness. The frequency of developmental abnormalities varied along two independent natural thermal gradients, exceeding 10% in adults eclosing from larvae developing in warm, sunlit fruit. When exposed to natural heat stress, D. melanogaster larvae with the wild-type number of hsp70 genes (n=10) developed abnormal wings significantly more frequently than a transgenic sister strain with 22 copies of the hsp70 gene.

Molecular thermal telemetry of free-ranging adult Drosophila melanogaster.

The expression of two temperature-sensitive reporter genes, hsp70 and an hsp70-LacZ fusion, in free-ranging adult Drosophila melanogaster indicates that natural thermal stress experienced by such small and mobile insects may be either infrequent or not severe. Levels of the heat-shock protein Hsp70, the major inducible Hsp of Drosophila, were similar in most wild Droso- phila captured after warm days to levels previously reported for unstressed flies in the laboratory. In a transgenic strain transformed with an hsp70-LacZ fusion (i.e., the structural gene encoding bacterial ß-galactosidase under control of a heat shock promoter), exposure to temperatures ≥32°C in the laboratory typically resulted in ß-galactosidase activities exceeding 140 mOD450 h-1µg-1 soluble protein. Flies caged in sun frequently had ß-galactosidase activities in excess of this level, whereas flies caged in shade and flies released and recaptured on cool days did not. Most flies (>80%) released on warm, sunny days had low ß-galactosidase activities upon recapture. Although the balance of recaptured flies had elevated ß-galactosidase activities on these days, their ß-galactosidase activities were <50% of levels for flies caged in direct sunlight or exposed to laboratory heat shock. These data suggest that even on warm days most flies may avoid thermal stress, presumably through microhabitat selection, but that a minority of adult D. melanogaster undergo mild thermal stress in nature. Both temperature-sensitive reporter genes, however, are limited in their ability to infer thermal stress and demonstrate its absence.

Image compression via improved quadtree decomposition algorithms.

Quadtree decomposition is a simple technique used to obtain an image representation at different resolution levels. This representation can be useful for a variety of image processing and image compression algorithms. This paper presents a simple way to get better compression performances (in MSE sense) via quadtree decomposition, by using near to optimal choice of the threshold for quadtree decomposition; and bit allocation procedure based on the equations derived from rate-distortion theory. The rate-distortion performance of the improved algorithm is calculated for some Gaussian field, and it is examined vie simulation over benchmark gray-level images. In both these cases, significant improvement in the compression performances is shown.