Calcium bicarbonate as an antimicrobial, antiviral, and prion‑inhibiting agent (Review)

Calcium bicarbonate does not act as a disinfectant at neutral pH; however, it exerts strong antimicrobial activity after it is placed in a high-voltage electric field, whereby it assumes an alkaline pH (12.4). Moreover, the microbicidal activity of the resulting solution (named CAC-717) is not influenced by the presence of organic material or resistance of the agent to inactivation. When sprayed on the skin surface, the pH of CAC-717 decreases rapidly to 8.84. CAC-717 comprises fine particles of 50-500 nm. When these mesoscopic crystals are dissolved in water, they destroy the genomes of bacteria or viruses and neutralize the infectious properties of abnormal prion proteins produced in ScN2a cells. The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic has resulted in unprecedented international demand for disinfectants. A small titer of SARS-CoV-2 remains infectious even after 30 sec in growth medium at pH 12.4. CAC-717 has exhibited a strong virucidal effect (3.6 to 4.4 log₁₀ decrease) against all examined SARS-CoV-2 isolates, including mutant forms. Similarly, human noroviruses also remain intact at pH 12.4; however, CAC-717 has been shown to cause a 3.25 log₁₀ reduction in norovirus genomic RNA compared to untreated samples. Existing evidence suggests that an unidentified mechanism controls the virucidal activity of CAC-717.

IgE reactivity to milk components in dogs with cutaneous adverse food reactions

We investigated the IgE reactivity to crude and purified milk antigens in the sera of 112 dogs with cutaneous adverse food reactions (CAFRs). Of the 112 dogs, 33 (29%) had specific IgE for crude milk antigens. In the dogs with milk-specific IgE, IgE reactivity to casein, bovine serum albumin (BSA), α-lactalbumin, β-lactoglobulin, and bovine IgG were 81%, 85%, 39%, 27%, and 35%, respectively. Casein and BSA may be important allergens in dogs with CAFRs. Some canine vaccines contain casein hydrolysate as a stabilizer and the pooled serum with anti-casein IgE showed IgE reactivity to the vaccines containing it. Information about IgE reactivity to casein in dogs with CAFRs could be useful for predicting adverse reactions to the vaccines including casein hydrolysate.

Results of food challenge in dogs with cutaneous adverse food reactions

BACKGROUND

Elimination diet trials and food challenge tests remain the gold standard for diagnosing cutaneous adverse food reaction (CAFR) in dogs. However, food challenge tests are difficult to perform owing to a lack of definite information on expected clinical signs and the time frame within which they develop after challenge.

OBJECTIVES

To report the results of the food challenge test carried out in client-owned dogs under observation.

METHODS AND MATERIALS

A retrospective evaluation of the medical records of dogs presenting with pruritus was performed. Skin infections and/or parasites were treated before inclusion in the study. Dogs that underwent an elimination diet with clinical improvement and relapse with food challenge tests were included in this study. A pruritus Visual Analog scale score was recorded as an index of pruritus before and at the end of the elimination diet trial before challenge. The onset of time to relapse of clinical signs and the body sites affected after food challenge testing were recorded by the owners.

RESULTS

We examined the medical records of 310 dogs with pruritus. Of these, 46 dogs with a diagnosis of CAFR were enrolled in this study. Significant clinical improvement was observed after the elimination diet trial (P < 0.0001). All dogs exhibited pruritus, and none exhibited anaphylaxis after food challenge testing. Among these dogs, 60.9% developed pruritus within 12 h of food challenge. Notably, 23.9% of the dogs developed pruritus within 3-6 h. The limbs exhibited the highest frequency of pruritus (56.5%), followed by the face (26.1%).

CONCLUSIONS AND CLINICAL RELEVANCE

This study is the first to report details of the time to onset of clinical signs and body site affected after food challenge testing in dogs. These results will assist veterinarians and dog owners in the decision-making process regarding food challenge testing.

Association analysis of non-synonymous polymorphisms of interleukin-4 receptor-α and interleukin-13 genes in canine atopic dermatitis

Interleukin-4 (IL4) and interleukin-13 (IL13) are involved in the initial response of T helper 2 lymphocytes through the activation of the IL4 receptor alpha (IL4RA), which is a common receptor chain for these cytokines. In humans, several single-nucleotide polymorphisms (SNPs) identified in the IL4R and in interleukin coding genes were associated with atopic disorders. However, the association between canine IL4R polymorphisms and atopic disorders has not been investigated yet. This study aimed to determine the associations between four non-synonymous SNPs and canine atopic dermatitis (CAD) in shiba inu and miniature dachshund populations. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis were used to genotype four polymorphisms of canine IL4R and IL13 in 34 shiba inu and 19 miniature dachshund patients with CAD, as well as 29 shiba inu and 39 miniature dachshund patients without the condition. Results from miniature dachshunds revealed a potential association between the presence of minor A allele rs24378020 and CAD (odds ratio, 0.10; 95% confidence interval, 0.01–0.85; P_original=0.0062). This CAD resistance allele led to an amino acid substitution (Arg688Cys) that could impair IL4 and IL13 signaling. In shiba inu patients, rs24378020 was fixed by homozygosity of the major G allele. No association was found between the remaining three evaluated SNPs and CAD. Nevertheless, the study suggests that the IL4R Cys688 variant reduces the risk of CAD in miniature dachshunds.

Inactivation of human norovirus and its surrogate by the disinfectant consisting of calcium hydrogen carbonate mesoscopic crystals

Human norovirus is one of the major causes of foodborne gastroenteritis, and it can be easily transmitted from infected person, virus-contaminated foods and environmental surfaces. Effective disinfection method is needed to stop the transmission of human norovirus. CAC-717 is a new disinfectant consisting of calcium hydrogen carbonate mesoscopic crystals. We aimed to evaluate the efficacy of CAC-717 against human norovirus. This study used human norovirus derived from fecal specimens and cultured murine norovirus, which is one of the surrogate viruses for human norovirus. The disinfection effect against murine norovirus was estimated by infectivity assay and transmission electron microscopy. The inactivation effect against human norovirus was assessed by reverse transcription polymerase chain reaction. Disinfection effect of CAC-717 against the infectivity of murine norovirus was shown within 100 s after the CAC-717 treatment, presenting the destruction of viral capsids. The treatment of CAC-717 significantly reduced human norovirus genomic RNA (3.25-log reduction) by the presence of the mesoscopic structure of calcium hydrogen carbonate. CAC-717 stably inactivated human norovirus in stool suspensions. The inactivation effect of CAC-717 against human norovirus was less susceptible to organic substances than sodium hypochlorite. CAC-717 would be a useful alternative for disinfecting human norovirus in contaminated environmental surfaces.

IgE sensitivity to Malassezia pachydermatis and mite allergens in dogs with atopic dermatitis

In this study, dogs with atopic dermatitis were separated into non-food-induced atopic dermatitis (NFIAD) group (n = 15) and food-induced atopic dermatitis (FIAD) group (n = 37) based on an elimination diet test. IgE reactivity for crude Malassezia pachydermatis (M. pachydermatis) and house dust mites (HDM) allergen extracts was investigated in the two groups using fluorometric enzyme-linked immunosorbent assay (ELISA) and intradermal skin test (IDST). Nine (60%) of the 15 dogs in NFIAD group and 6 (16%) of the 37 dogs in FIAD group showed specific IgE for M. pachydermatis (Mann-Whitney U-test, P < 0.01). By immunoblotting analysis, the pooled serum samples from dogs with IgE for M. pachydermatis showed IgE reactivity for 50 kDa protein of M. pachydermatis. Twelve (80%) of the 15 dogs in NFIAD group and 8 (22%) of the 37 dogs in FIAD group showed specific IgE for HDM (Mann-Whitney U-test, P < 0.01). In addition, the dogs in NFIAD group significantly show a positive IDST to M. pachydermatis and HDM extracts compared with the dogs in FIAD group. The results suggest that dogs with NFIAD are at increased risk of becoming sensitized to the normal commensal organism M. pachydermatis compared with dogs with FIAD, perhaps co-sensitization occurred due to an HDM protease antigen's, Der f 1 and/or Der p 1, proteolytic activity related epidermal skin barrier defects. Treatment to limit skin colonization may thus be especially important in NFIAD.

Identification of bovine papillomavirus type 1 and 2 from bovine anogenital fibropapillomas

Papillomavirus (PV) is a well-known pathogen associated with epithelial and mucosal neoplastic diseases. In contrast to human PVs, characterization of animal PVs from the aspect of anogenital neoplasm is still on a learning curve. In the present study, two vulval and one anal warts, histologically diagnosed as fibropapillomas, excised from dairy cattle were analyzed. PCR and sequencing revealed that bovine papillomavirus type 1 (BPV-1) and BPV-2 were detected from anal and vulval fibropapillomas, respectively. Immunohistochemistry detected PV antigen in a few differentiated keratinocytes of one vulval case. Reverse-transcriptase PCR detected the early region, but not the late region of BPV mRNA in all three cases. The present study will provide new insight into the relationship between BPV and anogenital papilloma in cattle.

Spontaneous regression of canine papillomavirus type 2-related papillomatosis on footpads in a dog

Persistent papillomatosis on footpads related to canine papillomavirus type 2 (CPV-2) infection has been described in dogs with immunocompromised condition. A 9-year-old, male French bulldog was presented with cauliflower-like nodules on the footpads of his left front leg. Histopathological examination revealed multiple finger-like projections of squamous epithelium with intranuclear inclusion bodies. Immunohistochemistry using an anti-bovine papillomavirus antibody demonstrated immunostaining in the keratinocytes. Partial genome DNA of CPV-2 was amplified from the lesion. Full genome sequence of CPV-2 in the subject showed 99.95% nucleotide identity with that of CPV-2 from the reference data. Two weeks after a biopsy, the skin lesion spontaneously regressed without any specific treatment. In non-immunocompromised dogs, CPV-2-related footpad papillomatosis could spontaneously resolve after a biopsy.

Full genome analysis of bovine papillomavirus type 1 derived from a calf with severe cutaneous multiple papillomatosis

Severe papillomatosis occasionally causes astasia leading to euthanizing cattle. There are currently a limited number of reports on virologic approach in severe bovine papillomatosis. Here we report a full genome characterization of bovine papillomavirus type 1 (BPV-1) from the case of severe papillomatosis. A calf developed numerous papillomas on the skin and some nodules in the upper gastrointestinal tract at seven months old. The skin lesion was diagnosed as the epithelial papilloma with BPV antigen expression, while the gastrointestinal lesions were diagnosed as the fibropapilloma without BPV antigen. Full genome analysis revealed that BPV-1s detected in all the lesions were exactly the same. Compared with the reference BPV-1 sequence, there was a single nucleotide insertion in the upstream regulatory region.

Detection of felis catus papillomavirus type 3 and 4 DNA from squamous cell carcinoma cases of cats in Japan

Association of felis catus papillomaviruses (FcaPVs) with feline squamous cell carcinoma (SCC) has been reported worldwide, while there is limited information about FcaPVs in Asia. In this study, 21 feline SCC biopsy samples from cats in Japan were analyzed by PCR with PV consensus primers and type-specific primers for FcaPV type 2 (FcaPV-2), FcaPV-3 and FcaPV-4 designed in this study. Sequence analysis revealed that one sample was FcaPV-3, and two were FcaPV-4. In both FcaPV-4 positive samples, 334th tryptophan in L1 ORF was deleted compared with the reference sequence. Moreover, immunohistochemistry showed that p16 protein was positive in both FcaPV-4 detected samples. This study would contribute to the molecular epidemiological and pathological understanding of FcaPV in Japan.

Characterization of Pseudomonas aeruginosa phage KPP21 belonging to family Podoviridae genus N4-like viruses isolated in Japan

Bacteriophages (phages) belonging to the family Podoviridae genus N4-like viruses have been used as therapeutic agent in phage therapy against Pseudomonas aeruginosa infections. P. aeruginosa phage KPP21 was isolated in Japan, and phylogenetically investigated the phages belonging to this viral genus. Morphological and genetic analyses confirmed that phage KPP21 belongs to the family Podoviridae genus N4-like viruses. Moreover, phylogenetic analyses based on putative DNA polymerase and major virion protein showed that P. aeruginosa phages belonging to the genus N4-like viruses are separated into two lineages and that phage KPP21 is in the same clade as phage LUZ7.

Screening of KHP30-like prophages among Japanese Helicobacter pylori strains, and genetic analysis of a defective KHP30-like prophage sequence integrated in the genome of the H. pylori strain NY40

We have recently reported the active Helicobacter pylori bacteriophages (phages), KHP30 and KHP40, the genomic DNAs of which exist as episomes in host bacterial strains isolated in Japan (i.e. pseudolysogeny). In this study, we examined the possibility of the lysogeny of active KHP30-like phages in Japanese H. pylori strains, because their genomes contain a putative integrase gene. Only the NY40 strain yielded partial detection of a KHP30-like prophage sequence in PCR among 174 Japanese H. pylori isolates, except for strains producing the above active phages. Next, according to the genomic analysis of the NY40 strain, the KHP30-like prophage sequence was found to be located from ca. 524 to 549 kb in the host chromosome. The attachment sites, attL and attR, in the NY40 genome showed almost the same genomic location and sequence as those detected in a French isolate B38, suggesting that an active parental KHP30-like phage had integrated into the ancestral NY40 genome in a site-specific manner. The prophage found in the NY40 genome was assumed to have been genetically modified, after site-specific integration. These, together with the data in the KHP30-like prophages of other H. pylori genomes, suggest that the lysogenic state of the KHP30-like phages is generally unstable.

Cross-reactivity between major IgE core epitopes on Cry j 2 allergen of Japanese cedar pollen and relevant sequences on Cha o 2 allergen of Japanese cypress pollen

BACKGROUND

Cry j 2 and Cha o 2 are major allergens in Japanese cedar (Cryptomeria japonica; CJ) and Japanese cypress (Chamaecyparis obtusa; CO) pollen, respectively. Here, we assessed the epitopes related to the cross-reactivity between Cry j 2 and Cha o 2 using in vitro analyses.

METHODS

Peptides were synthesized based on Cry j 2 sequential epitopes and relevant Cha o 2 amino acid sequences. Four representative monoclonal antibodies (mAbs) against Cry j 2 were used according to their epitope recognitions. Serum samples were collected from 31 patients with CJ pollinosis. To investigate cross-reactivity between Cry j 2 and Cha o 2, ELISA and inhibition ELISA were performed with mAbs and sera from patients with CJ pollinosis.

RESULTS

Two of four mAbs had reactivity to both Cry j 2 and Cha o 2. Of these two mAbs, one mAb (T27) recognized the amino acid sequence (169)KVVNGRTV(176) on Cha o 2. This is related to the core epitope (169)KWVNGREI(176) on Cry j 2, which is an important IgE epitope. In addition, we found that these correlative sequences and purified allergens showed cross-reactivity between Cry j 2 and Cha o 2 in IgE of CJ patients.

CONCLUSIONS

We demonstrated the importance of (169)KVVNGRTV(176) in Cha o 2 for cross-reactivity with the Cry j 2 epitope (169)KWVNGREI(176), which plays an important role in allergenicity in CJ pollinosis. Our results are useful for the development of safer and more efficient therapeutic strategies for the treatment of CJ and CO pollen allergies.

Prevalence of food-responsive enteropathy among dogs with chronic enteropathy in Japan

There have been limited reports on the prevalence of adverse food reactions among dogs suffering from chronic enteropathy (CE) in Japan. We examined the prevalence and histological features of food-responsive enteropathy (FRE) in a total of 32 dogs with history of CE. Fourteen of 18 cases (56.2%) diagnosed as FRE had lymphocytic-plasmacytic enteritis or eosinophilic enteritis by histopathological examination. Characteristic histopathological changes indicating FRE were not identified in 18 cases, though 4 cases did not show any abnormalities. Results collected from this study provided important information that can help to change the way dogs with CE are treated in the future.

Intermediate-range chemical ordering of cations in molten RbCl-AgCl

A first sharp diffraction peak (FSDP) is observed in the X-ray total structure factor of a molten mixture of RbCl-AgCl, while both pure melts of RbCl and AgCl do not exhibit FSDP individually. Molecular dynamics simulations were performed to investigate the origin of the FSDP with the polarizable ion model (PIM). Coexistence of covalent Ag-Cl and ionic Rb-Cl bonds leads the system to evolve intermediate range ordering, which is simulated by introducing the induced polarization in different ways between Ag-Cl with fully polarizable treatment based on Vashishta-Raman potential and Rb-Cl with suppression over-polarization in the nearest neighbor contribution based on Born-Meyer potential. The partial structure factors for both the Ag-Ag and Rb-Rb correlations, SAgAg(Q) and SRbRb(Q), show a positive contribution to the FSDP, while SAgRb(Q) for the Ag-Rb correlation exhibits a negative contribution, indicating that Ag and Rb ions are distributed in an alternating manner within the intermediate-range length scale. The origin of the intermediate-range chemical ordering of cations can be ascribed to the preferred direction of the dipole moments of anions in the PIM.

Analysis of conformational and sequential IgE epitopes on the major allergen Cry j 2 of Japanese cedar (Cryptomeria japonica) pollen in humans by using monoclonal antibodies for Cry j 2

PURPOSE

Japanese cedar (Cryptomeria japonica; CJ) pollinosis is a type I allergy induced by CJ pollen, and Cry j 2 is one of the major allergens in this pollen. In a previous study, we analyzed IgE epitopes on Cry j 2 in humans by using synthetic peptides. The main purpose of this study was to identify B-cell epitopes on Cry j 2 in patients with CJ pollinosis by using monoclonal antibodies (mAbs) for Cry j 2.

METHODS

We used ELISA with mAbs for the epitope analysis. Sera samples were collected from 80 patients with CJ pollinosis, and allergenic epitopes for mAbs and human IgE were identified using ELISA with synthetic peptides. The importance of the epitopes for human IgE was analyzed using an inhibition ELISA.

RESULTS

Four independent epitopes (epitope #1, #2, #3, and #4) were identified on Cry j 2 with the use of mAbs. Epitope #3 and #4, corresponding to peptides No. 25 and No. 33, respectively, were newly determined as epitopes for mAbs and human IgE. Inhibition ELISA showed that not only epitope #2 (sequential) but epitope #1 (conformational) may play an important role in the CJ pollinosis.

CONCLUSIONS

Our results revealed 4 epitopes, including two new ones, on Cry j 2. We also found that inhibition ELISA with appropriate mAbs could be a viable method of evaluating the importance of the conformational and sequential epitopes for human IgE. These results are beneficial for the development of safer and more efficient therapeutic strategies for treating CJ pollinosis.

Large-scale survey of adverse reactions to canine non-rabies combined vaccines in Japan

Canine non-rabies combined vaccines are widely used to protect animals from infectious agents, and also play an important role in public health. We performed a large-scale survey to investigate vaccine-associated adverse events (VAAEs), including anaphylaxis, in Japan by distributing questionnaires on VAAEs to veterinary hospitals from April 1, 2006 through May 31, 2007. Valid responses were obtained for 57,300 vaccinated dogs at 573 animal hospitals; we obtained VAAEs information for last 100 vaccinated dogs in each veterinary hospital. We found that of the 57,300, 359 dogs showed VAAEs. Of the 359 dogs, death was observed in 1, anaphylaxis in 41, dermatological signs in 244, gastrointestinal signs in 160, and other signs in 106. Onset of VAAEs was mostly observed within 12 h after vaccination (n = 299, 83.3%). In this study, anaphylaxis events occurred within 60 min after vaccination, and about half of these events occurred within 5 min (n = 19, 46.3%). Furthermore, where anaphylaxis was reported, additional information to support the diagnosis was obtained by reinvestigation. Our resurvey of dogs with anaphylaxis yielded responses on 31 dogs; 27 of these demonstrated collapse (87.1%), 24 demonstrated cyanosis (77.4%), and both signs occurred in 22 (71.0%). Higher rates of animal VAAEs, anaphylaxis, and death were found in Japan than in other countries. Further investigations, including survey studies, will be necessary to elucidate the interaction between death and vaccination and the risk factors for VAAEs, and thus develop safer vaccines. Moreover, it may also be necessary to continually update the data of VAAEs.