Translational control of programmed cell death: eukaryotic translation initiation factor 4E blocks apoptosis in growth-factor-restricted fibroblasts with physiologically expressed or deregulated Myc

There is increasing evidence that cell cycle transit is potentially lethal, with survival depending on the activation of metabolic pathways which block apoptosis. However, the identities of those pathways coupling cell cycle transit to survival remain undefined. Here we show that the eukaryotic translation initiation factor 4E (eIF4E) can mediate both proliferative and survival signaling. Overexpression of eIF4E completely substituted for serum or individual growth factors in preserving the viability of established NIH 3T3 fibroblasts. An eIF4E mutant (Ser-53 changed to Ala) defective in mediating its growth-factor-regulated functions was also defective in its survival signaling. Survival signaling by enforced expression of eIF4E did not result from autocrine release of survival factors, nor did it lead to increased expression of the apoptosis antagonists Bcl-2 and Bcl-XL. In addition, the execution apparatus of the apoptotic response in eIF4E-overexpressing cells was found to be intact. Increased expression of eIF4E was sufficient to inhibit apoptosis in serum-restricted primary fibroblasts with enforced expression of Myc. In contrast, activation of Ha-Ras, which is required for eIF4E proliferative signaling, did not suppress Myc-induced apoptosis. These data suggest that the eIF4E-activated pathways leading to survival and cell cycle progression are distinct. This dual signaling of proliferation and survival might be the basis for the potency of eIF4E as an inducer of neoplastic transformation.

Targeting of U2AF65 to sites of active splicing in the nucleus

U2AF65 is an essential splicing factor that promotes binding of U2 small nuclear (sn)RNP at the pre-mRNA branchpoint. Here we describe a novel monoclonal antibody that reacts specifically with U2AF65. Using this antibody, we show that U2AF65 is diffusely distributed in the nucleoplasm with additional concentration in nuclear speckles, which represent subnuclear compartments enriched in splicing snRNPs and other splicing factors. Furthermore, transient expression assays using epitope-tagged deletion mutants of U2AF65 indicate that targeting of the protein to nuclear speckles is not affected by removing either the RNA binding domain, the RS domain, or the region required for interaction with U2AF35. The association of U2AF65 with speckles persists during mitosis, when transcription and splicing are downregulated. Moreover, U2AF65 is localized to nuclear speckles in early G1 cells that were treated with transcription inhibitors during mitosis, suggesting that the localization of U2AF65 in speckles is independent of the presence of pre-mRNA in the nucleus, which is consistent with the idea that speckles represent storage sites for inactive splicing factors. After adenovirus infection, U2AF65 redistributes from the speckles and is prefferentially detected at sites of viral transcription. By combining adenoviral infection with transient expression of deletion mutants, we show a specific requirement of the RS domain for recruitment of U2AF65 to sites of active splicing in the nucleus. This suggests that interactions involving the RS region of U2AF65 may play an important role in targeting this protein to spliceosomes in vivo.

Inhibition of clinical human immunodeficiency virus (HIV) type 1 isolates in primary CD4+ T lymphocytes by retroviral vectors expressing anti-HIV genes

Gene therapy may be of benefit in human immunodeficiency virus type 1 (HIV-1)-infected individuals by virtue of its ability to inhibit virus replication and prevent viral gene expression. It is not known whether anti-HIV-1 gene therapy strategies based on antisense or transdominant HIV-1 mutant proteins can inhibit the replication and expression of clinical HIV-1 isolates in primary CD4+ T lymphocytes. We therefore transduced CD4+ T lymphocytes from uninfected individuals with retroviral vectors expressing either HIV-1-specific antisense-TAR or antisense-Tat/Rev RNA, transdominant HIV-1 Rev protein, and a combination of antisense-TAR and transdominant Rev. The engineered CD4+ T lymphocytes were then infected with four different clinical HIV-1 isolates. We found that replication of all HIV-1 isolates was inhibited by all the anti-HIV vectors tested. Greater inhibition of HIV-1 was observed with transdominant Rev than with antisense RNA. We hereby demonstrated effective protection by antisense RNA or transdominant mutant proteins against HIV-1 infection in primary CD4+ T lymphocytes using clinical HIV-1 isolates, and this represents an essential step toward clinical anti-HIV-1 gene therapy.

Isolation and characterization of a dideoxyguanosine triphosphate-resistant mutant of human immunodeficiency virus reverse transcriptase

The appearance of drug-resistant strains of viral pathogens is a major difficulty confounding current efforts to block viral infections. The identification and analysis of mutations responsible for drug resistance can provide important clues helpful in understanding the mechanisms of resistance and in the eventual development of better therapies. We have used a direct screening method to scan libraries of mutagenized genes encoding the reverse transcriptase of human immunodeficiency virus type 1, and have recovered a variant enzyme that is resistant to the chain-terminator inhibitor 2',3'-dideoxyguanosine triphosphate. The single substitution mutation in this variant conferred broad crossresistance to a variety of other antiviral compounds currently in clinical trials. Virus carrying the mutation was fully infectious in cultured human lymphocytes. The replication of the mutant virus was highly resistant to phosphonoformic acid but did not show increased resistance to the prodrug dideoxyguanosine.

Efficient random subcloning of DNA sheared in a recirculating point-sink flow system

Based on a high-performance liquid chromatographic pump, we have built a device that allows recirculation of DNA through a 63-microm orifice with ensuing fractionation to a minimum fragment size of approximately 300 base pairs. Residence time of the DNA fragments in the converging flow created by a sudden contraction was found to be sufficiently long to allow extension of the DNA molecules into a highly extended conformation and, hence, breakage to occur at midpoint. In most instances, 30 passages sufficed to obtain a narrow size distribution, with >90% of the fragments lying within a 2-fold size distribution. The shear rate required to achieve breakage was found to be inversely proportional to the 1.0 power of the molecular weight. Compared with a restriction digest, up to 40% of all fragments could be cloned directly, with only marginal improvements in cloning efficiency having been observed upon prior end repair with Klenow, T4 polymerase or T4 polynucleotide kinase. Sequencing revealed a fairly random distribution of the fragments.

Dually incontinent nursing home residents: clinical characteristics and treatment differences

OBJECTIVE

Previous studies have described urinary and fecal incontinence in nursing homes and their separate effects on healthcare utilization. However, little is known about those who are incontinent of both.

DESIGN

Retrospective chart review.

SETTINGS

Twenty sites in three states

PARTICIPANTS

A total of 413 nursing home residents were categorized as having neither fecal nor urinary incontinence (C, n = 114), urinary incontinence only (UI, n = 53), fecal incontinence only (FI, n = 9), or were dually incontinent (DI, n = 237).

MEASUREMENTS

Charts were abstracted for sociodemographic information and health status information as well as utilization for the year before the date of abstraction. We then compared these characteristics across groups using ANOVA with pairwise comparisons and multiply adjusted regression.

RESULTS

Almost all patients with DI were cognitively and mobility impaired. However, there were no significant differences between the groups with respect to age and number of diagnoses. A diagnosis of stroke was also more common among those with DI compared with C. When examining healthcare utilization in multiply adjusted regression, dually incontinent residents received significantly fewer days of hospital care than those with UI.

CONCLUSIONS

Dual incontinence in NH residents is likely to have an important functional component. These residents seem to be treated less aggressively with respect to hospitalization compared with those with UI alone. The reasons for these differences need to be explored further.

Analysis of trans-dominant mutants of the HIV type 1 Rev protein for their ability to inhibit Rev function, HIV type 1 replication, and their use as anti-HIV gene therapeutics

The HIV-1 rev gene product facilitates the transport of singly spliced and unspliced HIV-1 transcripts and is necessary for productive HIV-1 infection. On the basis of the previously described trans-dominant Rev mutant M10, four point mutants and one frameshift mutant of the Rev protein were constructed. The mutants were inserted into retroviral expression vectors and analyzed for their ability to inhibit Rev-mediated gene expression. Transient transfection systems were used to screen these new mutants, and each was shown to inhibit expression of a Rev-dependent CAT reporter plasmid. Inhibition of HIV-1 envelope gene expression was tested in the HeLa-T4 cell line and was also shown to be inhibited by the trans-dominant Rev mutants. Retroviral vector producer cell lines were constructed and used to transduce Rev trans-dominant genes into the human T-cell line SupT1. The engineered SupT1 cell lines were then challenged with HIV-1 IIIB and HIV-1 expression was monitored by Northern blot analysis and in situ hybridization. SupT1 cells expressing either a Rev point mutant or the frameshift mutant showed greatly reduced HIV-1 mRNA accumulation and the Rev-dependent singly spliced and unspliced HIV-1 mRNAs were reduced. The kinetics of viral replication following challenge of Rev trans-dominant-engineered SupT1 cells with both HIV-1 IIIB and MN strains was significantly reduced and cells were protected from viral lysis. Viruses that emerge late in infection from Rev trans-dominant-engineered cultures are not resistant to Rev-mediated inhibition. Last, trans-dominant Rev-mediated protection of human CD4+ lymphocytes from challenge with primary HIV-1 patient isolates confirms the potential utility of this system as an anti-HIV-1 gene therapy approach.

Peritherapeutic Hemodynamic Changes of Carotid Stenting Evaluated with Quantitative DSA in Patients with Carotid Stenosis

BACKGROUND AND PURPOSE

Quantitative data from DSA have become important tools for understanding hemodynamic changes of intracranial lesions. In this study, we evaluated 8 hemodynamic parameters in patients before and after carotid artery angioplasty.

MATERIALS AND METHODS

DSA images of 34 patients with carotid stenosis who underwent angioplasty and stent placement were retrospectively analyzed. Eleven ROIs (M1, M2, A1, A2, the parietal vein, superior sagittal sinus, internal jugular vein, and 4 in the ICA) were selected on color-coded DSA. Eight hemodynamic parameters (bolus arrival time, TTP, relative TTP, full width at half maximum, wash-in slope, washout slope, maximum enhancement, and area under the curve) were measured from the time-concentration curves of these ROIs. The dependent t test for paired samples was applied to these parameters before and after stent placement.

RESULTS

We found that the treatment significantly reduced TTP, relative TTP, bolus arrival time, and washout slope at all arterial ROIs and full width at half maximum and area under the curve at some arterial ROIs. Bolus arrival time was significantly reduced after treatment for all arterial ROIs, the parietal vein, and the superior sagittal sinus. The maximum enhancement and wash-in slope did not show significant changes after treatment. After treatment, the relative TTP from the ICA to M1, M2, and the parietal vein returned to normal values.

CONCLUSIONS

In addition to TTP and relative TTP, other parameters can be used to evaluate peritherapeutic cerebral hemodynamic changes. Bolus arrival time has the potential to evaluate brain circulation at arterial and venous sites, especially when TTP cannot be measured because of an incomplete time-concentration curve.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Gastricsin and cathepsin D in normal and hypertrophic human prostates

The relative contents of gastricsinogen, the inactive zymogen precursor of gastric gastricsin (EC 3.4.23.3), and cathepsin D (EC 3.4.23.5) in normal and benign hyperplasia of the prostate gland have been determined. Gastricsinogen levels are significantly lower (0.116 +/- 0.02 U/gm. wet tissue) in the hyperplastic than in normal prostates (0.65 +/- 0.06 U/gm.). Conversely, cathepsin D levels are higher in the diseased (0.705 +/- 0.17 U/gm.) as opposed to normal prostatic tissue (0.39 +/- 0.12 U/gm.). The average gastricsin-cathepsin D differences between the 2 tissues (0.26 +/- 0.025 for normal prostates and -0.59 +/- 0.057 SEM for hyperplastic tissue) are also significantly different (p less than 0.001). It is suggested that the simple determination of these 2 acid proteinases in prostate homogenates could be used as alternative and complementary marker enzymes for the study of the physiopathologic status of the prostate gland.

Nutrition Profile and Animal-Tested Safety of Morchella esculenta Mycelia Produced by Fermentation in Bioreactors

Morchella esculenta (ME), or “true” morel mushrooms, are one of the most expensive mushrooms. M. esculenta contain all the important nutrients including carbohydrates, proteins, polyunsaturated fatty acids, and several bioactive compounds such as polysaccharides, organic acids, polyphenolic compounds, and tocopherols, which are promising for antioxidant, immunomodulation, anti-cancer, and anti-inflammatory applications. However, the M. esculenta fruiting body is difficult to collect in nature and the quality is not always reliable. For this reason, the cultivation of its mycelia represents a useful alternative for large-scale production. However, for M. esculenta mycelia to be used as an innovative food ingredient, it is very important to prove it is safe for human consumption while providing high-quality nutrients. Hence, for the first time in this study, the nutritional composition, as well as 90 days of oral toxicity of fermented ME mycelia in Sprague Dawley rats, is examined. Results showed that the ME mycelia contained 4.20 ± 0.49% moisture, 0.32 ± 0.07% total ash, 17.17 ± 0.07% crude lipid, 39.35 ± 0.35% crude protein, 38.96 ± 4.60% carbohydrates, and 467.77 ± 0.21 kcal/100 g energy, which provides similar proportions of macronutrients as the U.S. Dietary Reference Intakes recommend. Moreover, forty male and female Sprague Dawley rats administrating ME mycelia at oral doses of 0, 1000, 2000, and 3000 mg/kg for 90 days showed no significant changes in mortality, clinical signs, body weight, ophthalmology, and urinalysis. Although there were alterations in hematological and biochemical parameters, organ weights, necropsy findings, and histological markers, they were not considered to be toxicologically significant. Hence, the results suggest that the no-observed-adverse-effects level (NOAEL) of ME mycelia was greater than 3000 mg/kg/day and can therefore be used safely as a novel food at the NOAEL.

DNA sequence characterization of the G gene region of bacteriophage Mu

The nucleotide sequence of a 1.2 kb region of bacteriophage Mu DNA was determined. This region contains the 3' end of the F gene, the complete G gene, and the 5' end of the I gene, all late genes involved in Mu virion morphogenesis. Identity of the G gene open reading frame was confirmed by sequencing four Gam mutations. The G open reading frame is predicted to encode proteins of 16.7 or 17.2 kDa, depending on which of two possible start codons are used to initiate translation. Four new nuB mutations in the DNA gyrase-binding site between the G and I genes were also sequenced and found to be identical to the nuB103 mutation sequenced previously.

Some quantitative aspects of myoplasmic ATPMg and total internal ATP and ArP levels in resting barnacle muscle fibres

1. Flash height recorded following the injection of firefly into the external calibration medium depends on the concentration of K-glutamate used, e.g. 120 mM K glutamate reduces flash height by approximately 20 percent. 2. Suspending the fibre in air instead of artificial sea water (ASW) or replacement of NaCl in the bathing medium with Na-glutamate fails to alter flash height. 3. Firefly preparations from DuPont, Packard and SAI give similar myoplasmic ATPMg values viz. 1.1 mM. 4. Analysis of 36 fibres shows the following: myoplasmic ATP = 1.03 +/- 0.06 mM; total ATP (firefly method) = 5.26 +/- 0.12 mmol/kg water; total ATP (enzymic fluorimetry) = 6.27 +/- 0.13 mmol/kg water and ArP = 20.76 +/- 0.59 mmol/kg water. 5. Measurement of ATPMg in samples of myoplasmic aspirate gives a value that is greater than that obtained in situ. 6. Iodoacetate, whether applied externally or internally, reduces resting luminescence in a dose-dependent manner. It also reduces myoplasmic ATP and total ATP. 7. 2-Deoxy-d-glucose fails to reduce myoplasmic ATP but reduces total ATP. 8. Diethylpyrocarbonate, whether applied externally or internally, reduces myoplasmic ATP. It also causes a slow decline in ArP but little change in total ATP. 9. Injection of L-arginine causes a fall in resting luminescence in some fibres while in others it causes a prompt transitory rise. Injection of L-arginine also causes a fall in total ATP. 10. Collectively, these results suggest that the immediate buffering system in the myoplasm is ArP and that ATP supplied by glycolysis lies in a compartment, presumably the interfibrillar space, which is inaccessible to injected firefly.

The nature of the increased sensitivity to injected GTP of the sodium efflux in barnacle muscle fibers pre-exposed to aldosterone

A study has been made of the increased sensitivity to injected GTP of the sodium efflux in barnacle muscle fibers pre-exposed to aldosterone and of the problem whether or not aldosterone acts by raising the internal ATP level. The results indicate that increased sensitivity to injected GTP develops fully some 8 hr following external application of 10(-6) M aldosterone. Neither actinomycin D nor cycloheximide abolishes this extrasensitivity. This is also true of colchicine and cytochalasin B. The magnitude of the sustained response to injected "dialyzed" cholera toxin or cAMP-protein kinase catalytic subunit is practically the same as that of unexposed fibers. Internal ATP levels in pre-exposed fibers are higher than in unexposed fibers, even in the presence of cycloheximide. Injection of ADP (0.1 M) raises the ATP levels and reduces the ArP levels, more so in unexposed fibers. The suggestion is made that extrasensitivity of pre-exposed fibers to injected guanine nucleotides represents a post-translational phenomenon which might involve delay in the reassociation of R2 with C (of cAMP-PK).

Partial characterization of pepsins and gastricsins and their zymogens from human and toad gastric mucosae

1. Three zymogens have been isolated from human gastric mucosae and two from the stomachs of the toad Caudiverbera caudiverbera. 2. Human zymogens I and III were immunologically related and cross-reacted with antisera prepared against porcine pepsinogen. The third, (II), showed no cross-reactivity. 3. Human zymogens I and III and toad zymogen ZII gave rise to two human pepsins and to a pepsin-like enzyme, respectively. 4. Human zymogen II (gastricsinogen) and toad zymogen ZI gave rise to human gastricsin and to a gastricsin-like enzyme respectively. 5. The toad enzymes showed much greater stability at neutral and alkaline pH values than the human enzymes.

Predictors of medication prescription in nursing homes

OBJECTIVES

To identify patient characteristics associated with higher numbers of prescribed drugs or risk of receiving one or more inappropriate medications.

DESIGN

A cross-sectional survey using chart reviews.

PARTICIPANTS

A total of 414 long-stay residents of 20 nursing homes in three states

MEASUREMENTS

Current medication orders, sociodemographic information, and diagnoses and health status information as indicated by the MDS. The number of routine, total, and inappropriate medications were tabulated.

RESULTS

Higher numbers of medications were associated with higher total numbers of diseases. In addition, several diseases (congestive heart failure, hypertension, depression, anxiety, and diabetes) were associated with higher numbers of medications even after controlling for total disease burden. Cognitive impairment was associated with fewer medications after controlling for total number of diseases. Advanced age also attenuated the effect of disease burden on the number of total and routine medications. The only independent predictor of more inappropriate medications was higher numbers of routine medications.

CONCLUSION

Several specific disease states predispose patients to prescription of higher numbers of medication, and, these patients must be managed more carefully to prevent adverse drug-drug or drug-disease interactions. Why patients with compromised cognitive status receive fewer medications requires further study.