Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice from lethal challenge

Efficient vaccines potentiate antibody avidity and increase T cell longevity, which confer protection against microbial lethal challenge. A vaccine strategy was established by using Lactobacillus acidophilus to deliver Bacillus anthracis protective antigen (PA) via specific dendritic cell-targeting peptides to dendritic cells (DCs), which reside in the periphery and mucosal surfaces, thus directing and regulating acquired immunity. The efficiency of oral delivery of L. acidophilus expressing a PA-DCpep fusion was evaluated in mice challenged with lethal B. anthracis Sterne. Vaccination with L. acidophilus expressing PA-DCpep induced robust protective immunity against B. anthracis Sterne compared with mice vaccinated with L. acidophilus expressing PA-control peptide or an empty vector. Additionally, serum anti-PA titers, neutralizing PA antibodies, and the levels of IgA-expressing cells were all comparable with the historical recombinant PA plus aluminum hydroxide vaccine administered s.c. Collectively, development of this strategy for oral delivery of DC-targeted antigens provides a safe and protective vaccine via a bacterial adjuvant that may potentiate mucosal immune responses against deadly pathogens.

Long-term tacrine (Cognex) treatment: effects on nursing home placement and mortality, Tacrine Study Group

OBJECTIVE

To assess the possible association between tacrine (Cognex, manufactured by Parke-Davis, Morris Plains, NJ) dose and likelihood of nursing home placement (NHP) or death in patients with AD.

DESIGN

A 30-week, randomized, double-blind, placebo-controlled, parallel-group multicenter clinical trial involving 663 patients, after which patients were treated openly and followed up a minimum of 2 years later.

PATIENTS

At baseline, outpatients were at least 50 years of age, met criteria for probable AD, with baseline Mini-Mental State Examination scores between 10 and 26 (inclusive), were otherwise healthy, and had a caregiver who could provide assessments and ensure medication compliance.

INTERVENTIONS

mandomized assignment to placebo or one of three ascending dosage regimens of tacrine over 30 weeks, followed by open label treatment for all patients who began the double-blind trial.

OUTCOME MEASURES

NHP and death were examined using logistic regression.

RESULTS

PATIENTS who remained on tacrine and were receiving doses > 80 mg/d or > 120 mg/d were less likely to have entered a nursing home than patients on lower doses (odds ratios > 2.7,2.8, respectively.) There was a trend for lower mortality for patients receiving > 120 mg/d (p = 0.063).

CONCLUSIONS

Treatment with tacrine at doses > 80 mg/d was associated with a reduced likelihood of NHP. These data demonstrate that tacrine's 30-week effects on cognitive function and clinicians' global ratings may generalize to effects on a major milestone of AD. Future studies should attempt to replicate these findings prospectively.

In vitro activity of the nitrogen fixation regulatory protein NIFA

We have detected activity of the nitrogen fixation regulatory protein NIFA of Klebsiella pneumoniae in vitro. To do so we directed synthesis of NIFA in a coupled transcription-translation system and detected its ability to activate expression of a translational fusion between the nifH and lacZ genes. We infer that NIFA stimulates initiation of transcription by sigma 54 holoenzyme from the nifHDK promoter. The activity of NIFA was lost rapidly under both aerobic and anaerobic conditions at 30 degrees C and was lost somewhat less rapidly at 0 degrees C. Loss of activity was not accompanied by degradation of NIFA polypeptide. Loss of activity was approximately exponential and was not affected by NIFA concentration over a 5-fold range. Therefore, NIFA inactivation does not appear to be due to self-association. We found that the factor in crude extracts previously demonstrated to bind to the nifHDK promoter-regulatory region [Beynon, J., Cannon, M., Buchanan-Wollaston, V., and Cannon, F. (1983) Cell 34, 665-671] is the integration host factor, which is known to bend DNA. Since the binding site for integration host factor lies between the upstream binding site for NIFA and the nifHDK promoter, integration host factor may bend the DNA between these two sites to facilitate productive interactions between NIFA and sigma 54 holoenzyme.

Angiotensin converting enzyme inhibitor induced angio-oedema: a review of the pathophysiology and risk factors

Angio-oedema (AE) is a known adverse effect of angiotensin converting enzyme inhibitor (ACE-I) therapy. Over the past several decades, evidence of failure to diagnose this important and potentially fatal reaction is commonly found in the literature. Because this reaction is often seen first in the primary care setting, a review was undertaken to analyse and document the keys to both diagnostic criteria as well as to investigate potential risk factors for ACE-I AE occurrence. A general review of published literature was conducted through Medline, EMBASE, and the Cochrane Database, targeting ACE-I-related AE pathomechanism, diagnosis, epidemiology, risk factors, and clinical decision making and treatment. The incidence and severity of AE appears to be on the rise and there is evidence of considerable delay in diagnosis contributing to significant morbidity and mortality for patients. The mechanism of AE due to ACE-I drugs is not fully understood, but some genomic and metabolomic information has been correlated. Additional epidemiologic data and clinical treatment outcome predictors have been evaluated, creating a basis for future work on the development of clinical prediction tools to aid in risk identification and diagnostic differentiation. Accurate recognition of AE by the primary care provider is essential to limit the rising morbidity associated with ACE-I treatment-related AE. Research findings on the phenotypic indicators relevant to this group of patients as well as basic research into the pathomechanism of AE are available, and should be used in the construction of better risk analysis and clinical diagnostic tools for ACE-I AE.

A nuclear matrix-specific factor that binds a specific segment of the negative regulatory element (NRE) of HIV-1 LTR and inhibits NF-kappa(B) activity

The negative regulatory element (NRE) of human immunodeficiency virus type-1 (HIV-1) long terminal repeat (LTR) is a defined region that has been reported to downregulate LTR-directed HIV gene expression. However, information on the precise role of this region in regulating HIV gone transcription is lacking. We have investigated the possibility that these NRE sequences regulate HIV transcription by a mechanism mediated through a nuclear matrix-specific DNA-protein interaction. We find a nuclear matrix attachment region (MAR) present within the NRE of the HIV-1 LTR that recognizes a sequence-specific DNA-binding protein present in the nuclear matrix of HIV infected cells. Moreover, we also show that the purified DNA-binding nuclear matrix protein (NMP) specifically represses the DNA-binding activity of NF-kappaB. It is likely that the MAR and MAR-enriched specific DNA-binding NMP are brought into juxtaposition by the non-chromatin scaffolding of the nucleus, thus influencing NF-kappaB (and other nuclear proteins) DNA-binding activity through protein-protein and protein-DNA interactions. Our date suggest that one possible role of the NRE could be to act as a matrix attachment site in the nuclear matrix, thus, allowing interaction with a sequence-specific trans-acting factor. The negative effect on NF-kappaB activity due to this MAR-NMP-specific interaction provides a mechanism by which the NRE downregulates HIV gene expression.

Early human trials in the assessment of cognition activators

The assessment of cognition enhancers in the clinic is a broad topic that can be addressed from both academic/theoretical and therapeutic/drug development perspectives. The most important first step is to decide which perspective one is employing and to clearly specify, a priori, the goal of any intended study. Since the therapeutic benefit of cognition enhancers is not apparent until after many weeks of exposure, it is virtually impossible to demonstrate efficacy in early, short-duration Phase 2 trials. It is possible, however, to gain some knowledge of the doses that effect CNS, rCBF, PET etc. in either normal volunteers or the population of interest. However, these results should not be interpreted as evidence for, or lack of, efficacy. Recently, there has been growing interest in the reversal of scopolamine- or benzodiazepine-induced memory deficits in humans. A major problem is the potential for overinterpretation of the results of such studies. From a drug development approach, it is necessary to utilize larger numbers of subjects and longer-term studies. Specification of the indication should be as precise as possible and the outcome measures should accurately reflect both the current state of the patient and the course of the disease. The absence of normative and longitudinal data on such measures is a hurdle that is only now being overcome. Such data provide a scientific basis for the determination of the types of design and sample sizes that give adequate power to thoroughly assess new cognition enhancers.

Tat mediates transcriptional activation of HIV-1 gene in vitro

Gene expression of human immunodeficiency virus (HIV-1) is greatly enhanced by a viral transactivator, the Tat protein, which interacts with R region sequences of the HIV-1 long terminal repeat (LTR). There is no direct evidence to indicate transcriptional activation of HIV-1 by Tat. Using an in vitro transcription system, we demonstrate that an established mouse cell line, which constitutively expresses Tat protein, selectively stimulates the steady state levels of the transcripts directed from the long terminal repeat (LTR) sequences of HIV-1. The gel binding retardation assays further demonstrate a stable activated complex, formed due to direct binding of Tat to DNA elements of the HIV-1 LTR. These data implicate transcription as the site of Tat action in trans-activation and could play an essential role in human immunodeficiency virus replication, similar to the nuclear trans-activators of other viruses.

c-erbB-2 promoter-specific DNA-binding protein isolated from human breast cancer tissues displays mitogenic activity

Amplification and overexpression of the c-erbB-2 gene appears to play a role in the pathogenesis of human breast and other cancers. Frequent amplification (20-30%) of the c-erbB-2 gene was observed in human adenocarcinomas of kidney, pancreas, lung, ovarian, and breast cancer. The gene product is a 185-kDa glycoprotein that has intrinsic tyrosine kinase activity and is believed to be a receptor. Several candidate ligands have been described. In the present study we have identified and purified a novel DNA-binding protein from malignant human breast tissues. The protein binds to a core element (-22 to +9, +1 being the transcription start site) of the c-erbB-2 promoter region in a sequence-specific manner. The affinity-purified protein has the ability to induce DNA synthesis in quiescent NIH/3T3 cells, suggesting that the factor has mitogenic activity. The purified protein induces c-erbB-2 expression on the surface of microinjected NIH/3T3 cells. This DNA-binding protein is a sequence-specific cellular factor that is associated with high level expression of the c-erbB-2 gene and appears to play a role in cell transformation. Understanding the control and expression of this DNA-binding protein may shed light on the mechanism(s) of c-erbB-2 gene regulation and its potential role in the pathogenesis of human adenocarcinomas.

Outcomes of Proton Therapy for Patients with Infradiaphragmatic Lymphoma

PURPOSE/OBJECTIVE(S)

While the role of proton radiation (PT) in treating supradiaphragmatic targets in lymphoma patients is becoming increasingly well-established, outcomes of PT for infradiaphragmatic locations have not been reported. We report on the radiation planning details, doses achieved to key organs at risk (OARs), and clinical outcomes for a cohort of lymphoma patients treated with PT to infradiaphragmatic locations.

MATERIALS/METHODS

This is a single institution retrospective study of patients with biopsy-proven lymphoma who received PT to an infradiaphragmatic target between 2011-2022. Patient, disease, and radiation details were collected. Comparison photon plans were generated for a subset of patients. Toxicity was reported using CTCAE version 5.0. Dosimetric and clinical factors associated with toxicity and oncologic outcomes were assessed via linear regression, Wilcoxon rank sum test, Fisher's exact test, and/or independent t-test while the paired t-test or Wilcoxon signed rank test was used for dosimetric analyses.

RESULTS

38 patients comprising 40 PT courses were included. Median age was 63 years and median follow-up was 48 months. The most common diagnoses were DLBCL (58%) and Hodgkin lymphoma (18%). 28% of PT courses had direct overlap with a prior radiation field and 20% were palliative. Median dose was 30.6 GyE over 17 fractions to the retroperitoneum (30%), spine/paraspinal region (30%), pelvis (18%), inguinals (8%), spleen (3%), or other (8%). Top G1 toxicities were fatigue (65%), dermatitis (28%), and nausea (23%). 10% of PT courses led to a G2 toxicity and there were no G3+ toxicities. Higher number of fractions was associated with increased incidence of dermatitis (mean 16 vs. 19, p = 0.008), but no OAR parameters were associated with CTCAE toxicities. Among patients treated with curative intent, 44% experienced progression of disease (PD) at a median time of 3 months after PT; of these progressions, 60% were distant only, 20% were marginal only, 10% was marginal and distant, and 10% was in-field and distant. Higher number of systemic therapy lines received prior to PT was associated with increased likelihood of PD (mean 1.4 vs. 4.1, p = 0.01), and PD increased the risk of death (OR 15.3, 95% CI 2.5-95.2). 5/39 patients were diagnosed with a second malignancy after PT, two of which were hematologic. Among the 10 patients with photon comparison plans, PT provided a significant decrease in kidney doses (mean and V5), small bowel V5 Gy, large bowel V5 Gy, bowel bag V15 Gy, and mean liver (all p = 0.045 or less). However, average spinal cord/cauda Dmax was slightly higher with PT (24 vs. 25 Gy, p = 0.0156).

CONCLUSION

PT is a well-tolerated treatment for infradiaphragmatic lymphoma that leads to excellent outcomes with minimal high-grade toxicities. Compared to photon therapy, PT can significantly reduce doses to key abdominopelvic OARs.