Antiviral effect of theaflavins against caliciviruses.

Caliciviruses are contagious pathogens of humans and various animals. They are the most common cause of viral gastroenteritis in humans, and can cause lethal diseases in domestic animals such as cats, rabbits and immunocompromised mice. In this study, we conducted cytopathic effect-based screening of 2080 selected compounds from our in-house library to find antiviral compounds against three culturable caliciviruses: feline calicivirus, murine norovirus (MNV) and porcine sapovirus (PoSaV). We identified active six compounds, of which two compounds, both related to theaflavins, showed broad antiviral activities against all three caliciviruses; three compounds (abamectin, a mixture of avermectin B1a and B1b; avermectin B1a; and (-)-epigallocatechin gallate hydrate) were effective against PoSaV only; and a heterocyclic carboxamide derivative (BFTC) specifically inhibited MNV infectivity in cell cultures. Further studies of the antiviral mechanism and structure-activity relationship of theaflavins suggested the following: (1) theaflavins worked before the viral entry step; (2) the effect of theaflavins was time- and concentration-dependent; and (3) the hydroxyl groups of the benzocycloheptenone ring were probably important for the anti-calicivirus activity of theaflavins. Theaflavins could be used for the calicivirus research, and as potential disinfectants and antiviral reagents to prevent and control calicivirus infections in animals and humans.

Discovery and Synthesis of Heterocyclic Carboxamide Derivatives as Potent Anti-norovirus Agents.

There is an urgent need for structurally novel anti-norovirus agents. In this study, we describe the synthesis, anti-norovirus activity, and structure-activity relationship (SAR) of a series of heterocyclic carboxamide derivatives. Heterocyclic carboxamide 1 (50% effective concentration (EC50)=37 µM) was identified by our screening campaign using the cytopathic effect reduction assay. Initial SAR studies suggested the importance of halogen substituents on the heterocyclic scaffold and identified 3,5-di-boromo-thiophene derivative 2j (EC50=24 µM) and 4,6-di-fluoro-benzothiazole derivative 3j (EC50=5.6 µM) as more potent inhibitors than 1. Moreover, their hybrid compound, 3,5-di-bromo-thiophen-4,6-di-fluoro-benzothiazole 4b, showed the most potent anti-norovirus activity with a EC50 value of 0.53 µM (70-fold more potent than 1). Further investigation suggested that 4b might inhibit intracellular viral replication or the late stage of viral infection.

[Screening test for drugs in health foods using 2-dimensional TLC].

A simple and rapid method for screening of drugs in health foods using 2-dimensional TLC was established. The development systems were: (1) ethyl acetate/methanol/28% ammonia (85:10:5), (2) cyclohexane/toluene/diethyl amine (65:25:10), (3) methanol and (4) ethyl acetate/methanol/25% ammonia (85:10:5). System (1) and (2) were run as 2-dimensional high-performance TLC, and System (3) and (4) were run as 2-dimensional conventional TLC. Sample extracted with methanol from health foods was applied to standardized two 2-dimensional TLCs and 4 Rf values obtained from 4 development systems were compared with reference Rf values which were measured previously using standard materials. The repeatability of reference Rf values were secured by standardizing development conditions and pattern of 4 Rf values was specific for 80 drugs. Moreover, using 2-dimensional TLC enable to assign 4 Rf values to unknown substance without influence of matrix from health foods, so it was possible to determine drugs comparing 4 Rf values. This method could be applied as first screening test for prevention of health crisis occurred by drugs added to health foods illegally.

Evaluation of blood supply to the parathyroid glands in secondary hyperparathyroidism compared with histopathology.

BACKGROUND: In chronic renal failure patients, the parathyroid glands progress from diffuse hyperplasia to nodular hyperplasia, and it is important to distinguish between these as the latter form is more aggressive. This progress can be confirmed histologically, but the present study aimed to determine whether the different types of hyperplasia could be distinguished by power-Doppler ultrasonography (US). METHODS: Twenty-one consecutive renal failure patients were scheduled to undergo parathyroidectomy (PTx). Of 70 resected parathyroid glands, 63 were assessed by pre-operative power-Doppler US, classified into four groups based on the flow signal pattern and then correlated with the post-operative histopathology. RESULTS: With power-Doppler US imaging, 60.0% of glands without a signal inside the gland were diagnosed as diffuse hyperplasia or diffuse hyperplasia with early nodularity. Of glands with in-gland signals, 83.7% were nodular or had a single nodule typical of nodular hyperplasia. Even when the focus was on parathyroid glands weighing