Glucose facilitation of cognitive performance in healthy young adults: examination of the influence of fast-duration, time of day and pre-consumption plasma glucose levels

RATIONALE

Previous investigations have demonstrated increased performance after the administration of a glucose-load on certain aspects of cognitive functioning in healthy young adults. Generally these studies have used a procedure where participants were tested in the morning after an overnight fast.

OBJECTIVE

The aim of the present study was, for the first time, to investigate the glucose cognitive facilitation effect under more natural testing times and with shorter duration of the previous fast.

METHODS

Measures of verbal and non-verbal memory performance were compared under different fasting intervals (2-h fast versus overnight fast), times (morning versus afternoon) and glycaemic conditions (glucose versus aspartame drinks) in healthy young participants.

RESULTS

There was a significant glucose facilitation effect on long-term verbal memory performance. In addition, glucose significantly enhanced long-term spatial memory performance. The effect of glucose was essentially equivalent whether it was given after an overnight fast or a 2-h fast following breakfast or lunch. There was no effect of drink and time of day on working memory performance.

CONCLUSIONS

The results of this study further support the hypothesis that glucose administration can enhance certain aspects of memory performance in healthy young adults. More significantly, the findings indicate that this cognitive facilitation effect persists under more naturalistic conditions of glucose administration and is not restricted to long fast durations or morning administration.

A role of the C-terminal part of p44 in the promoter escape activity of transcription factor IIH

The p44 subunit plays a crucial role in the overall activity of the transcription/DNA repair factor TFIIH: on the one hand its N-terminal domain interacts with and regulates the XPD helicase (, ); on the other hand, as shown in the present study, it participates with the promoter escape reaction. Mutagenesis along with recombinant technology using the baculovirus/insect cells expression system allowed us to define the function of the two structural motifs of the C-terminal moiety of p44: mutations within the C4 zinc finger motif (residues 291-308) prevent incorporation of the p62 subunit within the core TFIIH. Double mutations in the RING finger motif (residues 345-385) allow the synthesis of the first phosphodiester bond by RNA polymerase II, but prevent its escape from the promoter. This highlights the role of transcription factor IIH in the various steps of the transcription initiation process.

Poly(lactic acid)-poly(ethylene glycol) nanoparticles as new carriers for the delivery of plasmid DNA

The purpose of the present work was to produce and characterize poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles (size lower than 300 nm) containing a high loading of plasmid DNA in a free form or co-encapsulated with either poly(vinyl alcohol) (PVA) or poly(vinylpyrrolidone) (PVP). The plasmid alone or with PVA or PVP was encapsulated by two different techniques: an optimized w/o/w emulsion-solvent evaporation technique as well as by a new w/o emulsion-solvent diffusion technique. Particle size, zeta potential, plasmid DNA loading and in vitro release were determined for the three plasmid-loaded formulations. The influence of the initial plasmid loadings (5, 10, 20 microg plasmid DNA/mg PLA-PEG) on those parameters was also investigated. The plasmid loaded into the nanoparticles and released in vitro was quantified by fluorimetry and the different molecular forms were identified by gel electrophoresis. PLA-PEG nanoparticles containing plasmid DNA in a free form or co-encapsulated with PVA or PVP were obtained in the range size of 150-300 nm and with a negative zeta potential, both parameters being affected by the preparation technique. Encapsulation efficiencies were high irrespective of the presence of PVA or PVP (60-90%) and were slightly affected by the preparation technique and by the initial loading. The final plasmid DNA loading in the nanoparticles was up to 10-12 microg plasmid DNA/mg polymer. Plasmid DNA release kinetics varied depending on the plasmid incorporation technique: nanoparticles prepared by the w/o diffusion technique released their content rapidly whereas those obtained by the w/o/w showed an initial burst followed by a slow release for at least 28 days. No significant influence of the plasmid DNA loading and of the co-encapsulation of PVP or PVA on the in vitro release rate was observed. In all cases the conversion of the supercoiled form to the open circular and linear forms was detected. In conclusion, plasmid DNA can be very efficiently encapsulated, either in a free form or in combination with PVP and PVA, into PLA-PEG nanoparticles. Additionally, depending on the processing conditions, these nanoparticles release plasmid DNA either very rapidly or in a controlled manner.

Bends in human mitotic metaphase chromosomes revisited: 15q11-13 is the most frequent non-random autosomal bend in blood cultures

We have investigated the preferential bending of some chromosome sites in blood cultures from normal and chromosomally abnormal subjects. A total of 2,262 centromeric and 2,718 non-centromeric bends were recorded, and 69 non-centromeric sites were found not to bend at random. 15q11-13 bending was found to be the most frequent non-random autosomal bend. Bends on chromosomes may be remnants of a folded chromosome state in the nucleus, and may facilitate the preferential involvement of some chromosomal bands in structural reorganizations such as the isoacentric fragments, or contribute to the high frequency of interstitial deletions and isodicentric inversion duplications involving the 15q11-13 region.

Nocardiosis revealed by thyroid abscess in a liver--kidney transplant recipient

Nocardiosis is a life-threatening infection, particularly among immunocompromised patients, which usually affects lungs, skin and central nervous system. We report a case of disseminated nocardiosis revealed by suppurative thyroiditis in a liver-kidney transplant recipient with poor nutritional status at the time of infection. Nocardia Asteroides was isolated from fine-needle aspiration material of the thyroid abscess. Clinical manifestations resolved after surgical drainage of the thyroid abscess, prolonged antibiotherapy and diminution of immunosuppressive regimen. Clinicians should be aware of this entity, as Nocardia Asteroides may need more than 5 days of culture to be isolated.

Recent strategies in the development of new human cytomegalovirus inhibitors

Human cytomegalovirus (HCMV) is one of the most common opportunistic infections in immunucompromised individuals, such as AIDS patients and organ transplant recipients, and is the most frequent congenital viral infection in humans. Despite a reduction of the incidence of AIDS-related opportunistic infections in patients under highly active antiretroviral treatment, attention should be paid to the HCMV risk factor in these individuals. Furthermore, HCMV may have an important role in atherosclerosis. Existing antiviral treatments for the HCMV infection suffer from poor bioavailability, toxicity, and limited effectiveness, mainly due to the development of drug resistance. Fortunately there are novel and potentially very effective new compounds undergoing pre-clinical and clinical evaluation. This review provides an overview in the last five years of new HCMV inhibitors (chemical structures, SAR, and new mechanisms of action) with the aim to provide new clues for the development of future drugs against this opportunistic virus.

Randomized phase III intergroup trial of isotretinoin to prevent second primary tumors in stage I non-small-cell lung cancer

BACKGROUND

Promising data have suggested that retinoid chemoprevention may help to control second primary tumors (SPTs), recurrence, and mortality of stage I non-small-cell lung cancer (NSCLC) patients.

METHODS

We carried out a National Cancer Institute (NCI) Intergroup phase III trial (NCI #I91-0001) with 1166 patients with pathologic stage I NSCLC (6 weeks to 3 years from definitive resection and no prior radiotherapy or chemotherapy). Patients were randomly assigned to receive a placebo or the retinoid isotretinoin (30 mg/day) for 3 years in a double-blind fashion. Patients were stratified at randomization by tumor stage, histology, and smoking status. The primary endpoint (time to SPT) and the secondary endpoints (times to recurrence and death) were analyzed by log-rank test and the Cox proportional hazards model. All statistical tests were two-sided.

RESULTS

After a median follow-up of 3.5 years, there were no statistically significant differences between the placebo and isotretinoin arms with respect to the time to SPTs, recurrences, or mortality. The unadjusted hazard ratio (HR) of isotretinoin versus placebo was 1.08 (95% confidence interval [CI] = 0.78 to 1.49) for SPTs, 0.99 (95% CI = 0.76 to 1.29) for recurrence, and 1.07 (95% CI = 0.84 to 1.35) for mortality. Multivariate analyses showed that the rate of SPTs was not affected by any stratification factor. Rate of recurrence was affected by tumor stage (HR for T(2) versus T(1) = 1.77 [95% CI = 1.35 to 2.31]) and a treatment-by-smoking interaction (HR for treatment-by-current-versus-never-smoking status = 3.11 [95% CI = 1.00 to 9.71]). Mortality was affected by tumor stage (HR for T(2) versus T(1) = 1.39 [95% CI = 1.10 to 1.77]), histology (HR for squamous versus nonsquamous = 1.31 [95% CI = 1.03 to 1.68]), and a treatment-by-smoking interaction (HR for treatment-by-current-versus-never-smoking = 4.39 [95% CI = 1.11 to 17.29]). Mucocutaneous toxicity (P<.001) and noncompliance (40% versus 25% at 3 years) were higher in the isotretinoin arm than in the placebo arm.

CONCLUSIONS

Isotretinoin treatment did not improve the overall rates of SPTs, recurrences, or mortality in stage I NSCLC. Secondary multivariate and subset analyses suggested that isotretinoin was harmful in current smokers and beneficial in never smokers.

Adult Still's disease associated with Mycoplasma pneumoniae infection

Adult Still's disease (ASD) is a systemic inflammatory disorder of unknown origin. Several reports have suggested a triggering infection in ASD. We describe a case of ASD associated with acute Mycoplasma pneumoniae infection. The close temporal relationship between ASD and acute infection strongly suggests that M. pneumoniae triggered ASD. We suggest that M. pneumoniae should be added to the list of infectious agents that may play a role in its etiology.

Pharmacological effects of elenoside, an arylnaphthalene lignan

Acute toxicity (24 h) and general behavior in mice of a lignan from Justicia hyssopifolia, a beta-D-glucoside (elenoside), was studied, and the cytotoxic activity was performed. Elenoside (arylnaphthalene lignan) in mice showed a moderate toxicity order (305 mg/kg) and central depressive properties at doses of 25, 50, and 100 mg/kg. It also displayed cytotoxic activity in a range of concentration of 10(-5)-10(-4) M when studied in the human tumor cell line panel of the US National Cancer Institute (NCI). The results indicated that elenoside has central depressant effects, and the cytotoxic activity of elenoside suggests that this compound and its genin derivatives merit further investigation as antitumoral drugs.

Distal third fibular aneurysmal bone cyst: en bloc resection and proximal third fibular reconstruction

Treatment of aneurysmal bone cysts (ABCs) located in the distal third fibula adjacent to the growth plate, can be problematic. The first choice of treatment for these lesions has been cyst curettage and bone graft. Complications include the high recurrence rate, possible growth-plate injury, and possible ankle instability associated with that treatment led to the development of other surgical options. We used en bloc resection and proximal third fibular bone reconstruction to treat an 8-year-old female patient with a distal third fibular ABC close to the growth plate. There was no recurrence, growth-plate injury, or ankle instability at 30-month follow-up.

[Iron deficiency anemia due to stromal tumor of the ileum]

Iron-deficiency anemia occurs in 3.5 to 5.3% of adult men and postmenopausal women. Occult gastrointestinal bleeding is the cause in the vast majority of cases. After endoscopic examinations have ruled out lesions in colon and upper gastrointestinal tract, 5 to 20% of those patients remain without diagnosis. Angiodysplasias and tumors are the most common causes of occult bleeding arising from the small bowel. Their diagnosis requires complex studies with quite low yield. However, it is necessary to perform them when anemia becomes severe or persistent. We report the case of a male patient with severe and persistent iron-deficiency anemia who had a stromal gastrointestinal tumor located in the ileum.

The Boston Diagnostic Aphasia Examination-Spanish version: the influence of demographic variables

The Boston Diagnostic Aphasia Examination Battery (BDAE) is one of the most widely used aphasia tests worldwide. Information about general population performance, however, is limited. This paper analyzes the effects of gender, age, socioeconomic status (SES), academic achievement, and occupation on the BDAE Spanish version. The BDAE was administered to a randomized sample of 156 occupationally active 19-60-year-old participants (75 male and 81 female) from two SES groups. Gender and age had a significant effect on some reading and writing subtests. Body-part naming and mechanics of writing scores were significantly decreased in the low SES group. Education had a significant impact over most of the BDAE subtests. A stepwise regression model showed that academic achievement was best able to predict the variance in BDAE scores with a low (< 15%) to modest (> 17%) but significant capability (F MANOVA p < .01). A factor analysis disclosed 7 factors that explained 67% of the total variance.

p44/SSL1, the regulatory subunit of the XPD/RAD3 helicase, plays a crucial role in the transcriptional activity of TFIIH

In order to unravel the mechanism that regulates transcription of protein-coding genes, we investigated the function of the p44 subunit of TFIIH, a basal transcription factor that is also involved in DNA repair. We have shown previously that mutations in the C terminus of the XPD helicase, another subunit of TFIIH, prevent its regulation by p44 (Coin, F., Bergmann, E., Tremeau-Bravard, A., and Egly, J. M. (1999) EMBO 18, 1357-1366). By using a site-directed mutagenesis approach within the p44 region from amino acids 66 to 200, we indicate how a decrease in the interaction between p44 and XPD results in a decrease of the XPD helicase activity and leads to a defect in the first steps of the transcription reaction, namely the first phosphodiester bond formation and promoter clearance. We thus provide some explanation for the transcriptional defect found in SSL1 mutated yeast (Wang, Z., Buratowski, S., Svejstrup, J. Q., Feaver, W. J., Wu, X., Kornberg, R. D., Donahue, T. F., and Friedberg, E. C. (1995) Mol. Cell. Biol. 15, 2288-2293). Moreover, this study shows how the activity of the the cyclin-dependent kinase-activating kinase associated with TFIIH complex in stimulating transcription is mediated in part by p44/XPD interaction.

Analysis of treatment results for floor-of-mouth cancer

OBJECTIVE

This study reports the results of treating floor-of-mouth cancer with five different treatment modalities with long-term follow-up.

STUDY DESIGN

Retrospective study of 280 patients with floor-of-mouth cancer treated in the Department of Otolaryngology-Head and Neck Surgery at Washington University Medical School (St. Louis, MO) from 1960 to 1994.

METHODS

Patients with biopsy-proven squamous cell carcinoma of the floor of mouth who were previously untreated were treated with curative intent by one of five modalities and were all eligible for 5-year follow-up. The treatment modalities included local resection alone, composite resection alone (with neck dissection), radiation therapy alone, local resection with radiation therapy, and composite resection with radiation therapy. Multiple diagnostic, treatment, and follow-up parameters were studied using standard statistical analysis to determine statistical significance.

RESULTS

The overall 5-year disease-specific survival (DSS) was 56% with death due to tumor in 44% of patients. The 5-year cumulative disease-specific survival (CDSS) was 0.61 (Kaplan-Meier probability) with a mean of 8.3 years and a median of 9.7 years. The DSS by treatment modality included local resection (76%), composite resection (63%), radiation therapy (43%), local resection with radiation therapy (61%), and composite resection with radiation therapy (55%). Overall, there was no significant difference in DSS by treatment modality. Recurrence at the primary site (41%) was the most common site of treatment failure. Nineteen percent of patients had recurrence in the neck. Eighty-eight percent of initial recurrences occurred within 60 months after the onset of treatment. Metastasis to a distant site occurred in 30% of patients. Twenty percent of these patients had second primary cancers, and 53% of these patients died of their second primary cancers.

CONCLUSIONS

Significantly improved 5-year DSS was seen in the patients with clear margins, early clinical tumor stage, and negative nodes. Significantly decreased 5-year survival was seen in the patients with involved margins, advanced clinical tumor stage, positive nodes, and tumor recurrence. Patients with no clinically positive nodes (cNO) can be observed safely for regional nodal disease and subsequent positive nodes can be treated as they occur with no adverse affect on survival. Because of high recurrence rates at the primary site and neck, and an increased rate of both distant metastasis and the development of second primary cancers, patients should be monitored closely for a minimum of at least 5 years.

The effect of hyperglycemia on cocaine neurotoxicity and death in mice

OBJECTIVE

Cocaine toxicity frequently manifests as seizures and status epilepticus. Frequently, dextrose is administered to patients with cocaine-induced seizures. The objective of this study was to examine the effect of pre-existing hyperglycemia on cocaine neurotoxicity and death in mice.

METHODS

Swiss albino mice received intraperitoneal dextrose at a dose of 1 g/kg (12.5%) (hyperglycemic group, n = 98). The euglycemic group (n = 98) received an equal volume of 0.9% saline. After 60 minutes, all the animals received intraperitoneal cocaine at a dose of 90 mg/kg. The times to onset of ataxia, seizure, and death were recorded in seconds. Times to events were compared using a Kaplan-Meier method and results were compared using the logrank test. The overall percentage outcomes were compared using chi-square.

RESULTS

The ataxia rates (hyperglycemic 97%, euglycemic 97%, chi(2) = 0, p = 1), seizure rates (hyperglycemic 85%, euglycemic 82%, chi(2) = 0.292, p = 0.589), and survival rates (hyperglycemic 62%, euglycemic 51%, chi(2) = 0.2514, p = 0.113) were similar between the groups. The survival following a seizure was significantly higher in the hyperglycemic group (hyperglycemic 57%, euglycemic 41%, chi(2) = 4.439, p = 0.035). The median ataxia time was earlier in the hyperglycemic group (190 sec) than in the euglycemic group (166 sec) (p = 0.031). Seizures occurred no earlier in the hyperglycemic group (331 sec) than in the euglycemic group (342 sec) (p = 0.207). Survival times were not different for the hyperglycemic group (9,133 sec) and the euglycemic group (7,593 sec) (p = 0.394). Survival times following seizures were not different for the hyperglycemic group (8,095 sec) and the euglycemic group (5,816 sec) (p = 0.0752).

CONCLUSIONS

In mice with pre-existing hyperglycemia, ataxia occurred earlier and survival following cocaine-induced seizures was longer than for euglycemic mice. No significant difference in the overall percentage of seizures and death was detected. Pre-existing hyperglycemia had minimal effect on worsening cocaine toxicity in mice.

Nonnucleoside human cytomegalovirus inhibitors: synthesis and antiviral evaluation of (chlorophenylmethyl)benzothiadiazine dioxide derivatives

A second generation of benzothiadiazine dioxide (BTD) derivatives was synthesized employing benzylation reactions mainly. The chlorophenylmethyl BTD derivatives showed activity against human cytomegalovirus (HCMV) with IC(50) values ranging from 3 to 10 microM. Their 50% cytotoxic concentrations were often >200 microM to lung fibroblast HEL cell proliferation and between 20 and 35 microM for lymphocyte CME cell growth. When cytotoxicity for cell morphology was considered, the minimum cytotoxic concentration for the different BTD derivatives varied between 5 and 200 microM. Some of the anti-HCMV compounds also showed activity against HIV-1 and HIV-2. The chlorophenylmethyl derivative 21 was active against a variety of HCMV clinical isolates from patients with different clinical manifestations and fully maintained its activity against a ganciclovir-resistant HCMV strain. The dibenzyl BTD derivatives did not inhibit HCMV protease, and preliminary pharmacological experiments revealed that their anti-HCMV action stems from interference with an early stage of the viral replicative cycle.