A novel class of broad-spectrum active-site-directed 3C-like protease inhibitors with nanomolar antiviral activity against highly immune-evasive SARS-CoV-2 Omicron subvariants

Antivirals with broad coronavirus activity are important for treating high-risk individuals exposed to the constantly evolving SARS-CoV-2 variants of concern (VOCs) as well as emerging drug-resistant variants. We developed and characterized a novel class of active-site-directed 3-chymotrypsin-like protease (3CLpro) inhibitors (C2-C5a). Our lead direct-acting antiviral (DAA), C5a, is a non-covalent, non-peptide with a dissociation constant of 170 nM against recombinant SARS-CoV-2 3CLpro. The compounds C2-C5a exhibit broad-spectrum activity against Omicron subvariants (BA.5, BQ.1.1, and XBB.1.5) and seasonal human coronavirus-229E infection in human cells. Notably, C5a has median effective concentrations of 30-50 nM against BQ.1.1 and XBB.1.5 in two different human cell lines. X-ray crystallography has confirmed the unique binding modes of C2-C5a to the 3CLpro, which can limit virus cross-resistance to emerging Paxlovid-resistant variants. We tested the effect of C5a with two of our newly discovered host-directed antivirals (HDAs): N-0385, a TMPRSS2 inhibitor, and bafilomycin D (BafD), a human vacuolar H+-ATPase [V-ATPase] inhibitor. We demonstrated a synergistic action of C5a in combination with N-0385 and BafD against Omicron BA.5 infection in human Calu-3 lung cells. Our findings underscore that a SARS-CoV-2 multi-targeted treatment for circulating Omicron subvariants based on DAAs (C5a) and HDAs (N-0385 or BafD) can lead to therapeutic benefits by enhancing treatment efficacy. Furthermore, the high-resolution structures of SARS-CoV-2 3CLpro in complex with C2-C5a will facilitate future rational optimization of our novel broad-spectrum active-site-directed 3C-like protease inhibitors.

The PERCIVAL detector: first user experiments

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

Long-term belatacept exposure maintains efficacy and safety at 5 years: results from the long-term extension of the BENEFIT study

The Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial randomized patients receiving a living or standard criteria deceased donor kidney transplant to a more (MI) or less intensive (LI) regimen of belatacept or cyclosporine A (CsA). The 5-year results of the long-term extension (LTE) cohort are reported. A total of 456 (68.5% of intent-to-treat) patients entered the LTE at 36 months; 406 patients (89%) completed 60 months. Between Months 36 and 60, death occurred in 2%, 1% and 5% of belatacept MI, belatacept LI and CsA patients, respectively; graft loss occurred in 0% belatacept and 2% of CsA patients. Acute rejection between Months 36 and 60 was rare: zero belatacept MI, one belatacept LI and one CsA. Rates for infections and malignancies for Months 36-60 were generally similar across belatacept groups and CsA, respectively: fungal infections (14%, 15%, 12%), viral infections (21%, 18%, 16%) and malignancies (6%, 6%, 9%). No new posttransplant lymphoproliferative disorder cases occurred after 36 months. Mean calculated GFR (MDRD, mL/min/1.73 m(2) ) at Month 60 was 74 for belatacept MI, 76 for belatacept LI and 53 for CsA. These results show that the renal function benefit and safety profile observed in belatacept-treated patients in the early posttransplant period was sustained through 5 years.

Evaluation of CT coronary artery angiography with 320-row detector CT in a high-risk population

OBJECTIVES

The aim of this article was to prospectively evaluate the accuracy and radiation dose of 320-detector row dynamic volume CT (DVCT) for the detection of coronary artery disease (CAD) in a high-risk population.

METHODS

60 patients with a high risk of CAD underwent DVCT without preceding heart rate control and also underwent invasive coronary angiography (ICA), which served as the standard reference.

RESULTS

On a per segment analysis, overall sensitivity was 95.3%, specificity was 97.6%, positive predictive value was 90.6%, negative predictive value was 98.8% and Youden index was 0.93. In both heart rate subgroups, diagnostic accuracy for the assessment of coronary artery stenosis was similar. The accuracy of the subgroup with an Agatston score ≥100 was lower than that for patients with an Agatston score <100. However, the difference between DVCT and ICA results was not significant (p=0.08). The mean estimated effective dose of CT was 12.5 ± 9.4 mSv. In those patients with heart rates less than 70 beats per minute (bpm), the mean radiation exposure of DVCT was 5.2 ± 0.9 mSv. The effective radiation dose was significantly lower than that of ICA (14.1 ± 5.9 mSv) (p<0.001). When the heart rate was >70 bpm, a significantly higher dose was delivered to patients with DVCT (22.6 ± 5.2 mSv, p<0.001) than with ICA (15.0 ± 5.3 mSv, p<0.001).

CONCLUSION

DVCT reliably provides high diagnostic accuracy without heart rate/rhythm control. However, from a dosimetric point of view, it is recommended that heart rate should be controlled to <70 bpm to decrease radiation dose.

Prognostic significance of immunohistochemical expression of Rb gene product in operable breast cancer

21121

Background: The aim of this study was to investigate the prognostic significance of the expression of Rb gene product in operable invasive breast cancer by performing immunohistochemical analysis. Methods: Between January 1993 and December 2001, 212 operable invasive breast cancer patients underwent immunohistochemical staining for Rb, and we retrospectively analyzed these results together with the clinical outcomes. Results: The overexpression of p53 was detected in 72.7% of the cases. The overexpression of Rb was correlated with positive hormonal receptor (p=0.000), and inversely correlated with lymph node metastasis (p=0.017) and vascular invasion (p=0.004). The tumor size, tumor histology, histologic grade, and tumor stage were not related to the overexpression of p53. Multivariate Cox regression analysis indicate that lymph node metastasis and tumor size were the significant prognostic factors for overall survival; lymph node metastasis was the significant prognostic factor for relapse free survival. On the subgroup analysis, the Rb expressors showed better 7-year overall survival (98.5% vs. 81.5%, respectively, p=0.005) and relapse free survival (94.1% vs. 77.4%, respectively, p=0.021) than did the p53 non-overexpressors for the patients without lymph node metastasis. However, for the patients with lymph node metastasis, the survival rates were not different for both the Rb expressors and the Rb non-expressors. Conclusions: Immunohistochemical staining of the Rb gene product was an independent prognostic factor for predicting survival of the lymph node negative operable breast cancer patients.

No significant financial relationships to disclose.

[Analysis on the data regarding brucellosis at the National Monitoring Center]

Surveillance on brucellosis was carried out in 15 major monitoring places in 14 provinces from 1990 to 1996. The result indicated that in a few monitoring places the epidemic situation was stable but in many monitoring places outbreak had occurred in one or two monitoring places. Major source of infection was from infected sheep and cattle while in some old epidemic areas the pastoral area was active, which kept animals continuously excrete bacteria, making the potential of outbreak brucellosis exist. A tendency showed that the epidemic area was shifting to the farming and stockbreeding and agricultural areas. A comprehensive strategy including effective management and control the circulation of causative agent, needs to be developed.

Reappraisal of the inspiratory effect of Bötzinger complex on phrenic nerve discharge

Experiments were done on 12 urethane-chloralose anaesthetized, vagotomized, paralysed and ventilated cats. The effects of electrical microstimulation at the augmenting expiratory neurons (Aug-e) of Bötzinger complex (Bot.c) were investigated. It was found that long train stimulation (100 Hz, 3-50 microA, 4-6 s) caused intensity-dependent inhibition of phrenic inspiratory discharge. The threshold for complete inhibition was 10 +/- 2 microA (mean +/- S.E.). The expiratory duration showed shortening at low intensity (< 7 microA) and prolongation at higher intensity. Short train stimulation (10 microA, 50 ms) delivered in inspiratory phase produced a two-part transient inhibition of phrenic discharge. The latencies of the first- and second-part inhibition were 4.7 +/- 0.16 ms and 95 +/- 3 ms, respectively. Complete termination of inspiration could be produced by a short train delivered at late inspiration. The results suggest the importance of the Aug-e neurons of Bot.c in determining inspiratory amplitude and respiratory phase duration.

Afferent projections to the Bötzinger complex from the upper cervical cord and other respiratory related structures in the brainstem in cats: retrograde WGA-HRP tracing

Following injection of WGA-HRP (30-60 nl, 5%) into the Bötzinger complex (Böt.c), a group of expiratory neurons in the vicinity of the retrofacial nucleus, a number of labeled neurons were observed, predominantly ipsilaterally, in the intermediate zone of the upper cervical cord at the C1 and C2 segments, the retrotrapezoid nucleus (RTN) in the ventrolateral medulla and the parabrachial-Kölliker-Fuse nuclear complex in the rostral pons. In addition, clusters of labeled cells were also observed in and around the solitary tract nucleus, nuclei ambiguus and retroambiguus, and nucleus raphe magnus. Control injections into the magnocellular tegmental field adjacent to the Böt.c resulted in a diffuse distribution of labeled neurons in the reticular formation. These results demonstrate that the Böt.c receives convergent monosynaptic axonal projections from the upper cervical spinal cord, the pontine pneumotaxic area, the RTN and several other respiratory related structures in the medulla.

Differential projections to the raphe nuclei from the medial parabrachial-Kölliker-Fuse (NPBM-KF) nuclear complex and the retrofacial nucleus in cats: retrograde WGA-HRP tracing

After injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP, 2 x 30 nl) [corrected] into the nucleus raphe magnus (NRM) of 6 cats, a number of retrogradely labelled neurons were observed in the rostral pons, mainly in the pontine pneumotaxic area, i.e., the medial parabrachial and Kölliker-Fuse (NPBM-KF) nuclear complex, and the tegmental field. In addition, a cluster of labelled cells was observed in the retrofacial nucleus (RFN) and its adjacent areas in the medulla. Control injections of the same volume of WGA-HRP into the medullary magnocellular tegmental field (2 mm lateral to the NRM) resulted in a much lower number of labelled neurons in the areas described above, and the labelled cells in the tegmental fields were predominant ipsilateral to the injected side. Injections into the nucleus raphe pallidus caudal to the NRM resulted in a diffuse distribution of labelled neurons, mainly in the tegmental fields of the pons and medulla. This study demonstrates that the NRM receives specific convergent projections from the NPBM-KF complex and the RFN in the medulla. It is suggested that these pathways are involved in the control of respiration.

Axonal projections from the pontine pneumotaxic region to the nucleus raphe magnus in cats

In 15 pentobarbital anesthetized and vagotomized cats, 60 non-respiratory units recorded from the medial parabrachial and Kölliker-Fuse nuclear complex (NPBM-KF), were found to be antidromically activated by electrical stimulation of the nucleus raphe magnus (NRM). Seven respiratory units (6 inspiratory, 1 expiratory), comprising 8.0% of the 87 respiratory units examined, were also antidromically activated by stimulation of the NRM. The antidromic latencies ranged from 0.4 to 2.5 ms (mean 1.2 ms). In 6 cats, following injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, a number of retrogradely labelled neurons were observed mainly in the NPBM-KF complex, and some in subcoeruleus nucleus and adjacent tegmental field. These results demonstrate that predominantly non-respiratory and a portion of respiratory neurons in the rostral pons, especially in the NPBM-KF complex, send a monosynaptic axonal projection to the NRM. It is suggested that the NPBM-KF to NRM pathway could be, in part, involved in the control of respiration as well as nociception control.

Descending axonal projections from the medial parabrachial and Kölliker-Fuse nuclear complex to the nucleus raphe magnus in cats

In 9 Nembutal-anesthetized and vagotomized cats, a total of 42 units, including 2 respiratory units, recorded from the medial parabrachial (NPBM) and Kölliker-Fuse (KF) nuclear complex were found to be antidromically activated by electrical stimulation of the nucleus raphe magnus (NRM). The latencies ranged from 0.4 to 2.5 ms (mean 1.1 ms). In 5 cats, following injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, a number of retrogradely labelled neurons were observed in the rostral pons, mainly in the NPBM, KF and nearby pontine area. These results demonstrate that mainly non-respiratory neurons in the rostral pons, especially in the NPBM and KF nucleus, send monosynaptic axonal projections to the NRM.

Studies on the inspiratory generating effect of the dorso-medial area of nucleus facialis

The responses in phrenic nerve activity resulting from stimulation and successive focal block of the dorso-medial area of nucleus facialis (dmNF) were studied in urethane anaesthetized rabbits. It was found that: (1) Long train stimulation (0.025-0.2 mA, 100 Hz) delivered to the dmNF caused marked prolongation in inspiratory duration and distinct increase in amplitude of phrenic discharge. Continuous inspiration with increased amplitude was usually observed during stimulation. (2) Short train stimulation (10 pulses, 100 Hz, 0.025-0.2 mA) during inspiration increased the duration and amplitude of inspiration. When the short train stimulation was delivered during expiration, inspiration would be initiated prematurely. (3) Microinjection of L-glutamate (0.5 M, 0.5-2 microliters) into the dmNF also increased inspiratory duration and amplitude. (4) Focal block of the dmNF by microinjection of lidocaine (2%, 1-2 microliters) produced strong depression or complete cessation of inspiration. In conclusion, the results of the present study show that the dmNF may play an important role in the neurogenesis of respiratory rhythm.