[Survey on the Number and Percentage of MR Safety Labeling Changed for Implantable Medical Devices].

PURPOSE: The purposes of this study were to investigate the number and percentage of items that changed magnetic resonance (MR) safety information labeling for implantable medical devices (IMDs) and to confirm the importance of checking the latest MR safety information database (117 types and 10031 items). METHODS: We investigated the number and percentage of MR safety labeling changed for IMDs in the MR safety information database as of December 2021 and August 2022. RESULTS: IMDs of MR Safety Unlabeled decreased from 4116 items (41.1%) to 859 items (8.6%). IMDs of MR Conditional increased from 4141 items (41.3%) to 5896 items (58.8%). CONCLUSIONS: Since there have been changes in the MR safety labeling for many IMDs, this study shows that it is important to confirm the latest MR safety information for IMDs.

Development of a Searchable System to Confirm MR Imaging Safety Information for Implantable Medical Devices.

The purpose of this study was to develop a searchable system to confirm magnetic resonance (MR) safety information of implantable medical devices (IMDs) to safely perform magnetic resonance imaging examinations. We labeled MR safety information for IMDs based on package insert descriptions and then categorized allowed MR conditions for IMDs. Finally, a searchable system was developed to use the database via the internet. This system enables efficient and accurate confirmation of MR safety information for IMDs.

A Web-based searchable system to confirm magnetic resonance compatibility of implantable medical devices in Japan: a preliminary study.

Confirmation of the magnetic resonance (MR) compatibility of implanted medical devices (IMDs) is mandatory before conducting magnetic resonance imaging (MRI) examinations. In Japan, few such confirmation methods are in use, and they are time-consuming. This study aimed to develop a Web-based searchable MR safety information system to confirm IMD compatibility and to evaluate the usefulness of the system. First, MR safety information for intravascular stents and stent grafts sold in Japan was gathered by interviewing 20 manufacturers. These IMDs were categorized based on the descriptions available on medical package inserts as: "MR Safe," "MR Conditional," "MR Unsafe," "Unknown," and "No Medical Package Insert Available". An MR safety information database for implants was created based on previously proposed item lists. Finally, a Web-based searchable system was developed using this database. A questionnaire was given to health-care personnel in Japan to evaluate the usefulness of this system. Seventy-nine datasets were collected using information provided by 12 manufacturers and by investigating the medical packaging of the IMDs. Although the datasets must be updated by collecting data from other manufacturers, this system facilitates the easy and rapid acquisition of MR safety information for IMDs, thereby improving the safety of MRI examinations.

The first reported case of canine subcutaneous Cryptococcus flavescens infection.

This report describes the first documented case of subcutaneous infection due to Cryptococcus flavescens in a dog. The chief symptoms of the patient dog were abscessed lesions on the dorsal muzzle, right eyelid, and lower jaw. Biopsy specimens from the lesions on the dorsal muzzle and lower jaw showed pyogranulomatous inflammation with numerous yeast cells. The patient dog was diagnosed with a subcutaneous fungal infection and orally received 5 mg/kg itraconazole once a day for 2 months, the abscesses disappeared. After 1 month at the end of treatment, the skin lesions did not redevelop. Isolates from the biopsy specimens were identified as C. flavescens by molecular analysis as well as morphologic and biochemical examination, indicating that C. flavescens is a potential canine pathogen.

Staphylococcus pseudintermedius exfoliative toxin EXI selectively digests canine desmoglein 1 and causes subcorneal clefts in canine epidermis.

Staphylococcal exfoliative toxins are known to digest desmoglein (Dsg) 1, a desmosomal cell-cell adhesion molecule, thus causing intraepidermal splitting in human bullous impetigo, staphylococcal scalded skin syndrome and swine exudative epidermitis. Recently, a novel exfoliative toxin gene (exi), whose sequence shares significant homology with previously identified exfoliative toxins, was isolated from Staphylococcus pseudintermedius. Little is known about the pathogenic involvement of this toxin in canine pustular diseases such as impetigo. The aim of this study was to determine whether EXI, the product of the exi gene, digests canine Dsg1 and causes intraepidermal splitting in canine skin. An exi gene was isolated from chromosomal DNA of an S. pseudintermedius strain obtained from a pustule of a dog with impetigo, and was used to produce a recombinant EXI by Escherichia coli expression. When purified recombinant EXI was injected intradermally into normal dogs, it caused the development of vesicles or erosions with superficial epidermal splitting. In addition, the EXI abolished immunofluorescence for Dsg1, but not for Dsg3, at the injection sites. Moreover, the EXI directly degraded baculovirus-secreted recombinant extracellular domains of canine Dsg1, but not that of canine Dsg3, in vitro. The EXI also degraded mouse Dsg1α and swine Dsg1, but not human Dsg1, mouse Dsg1ß and Dsg1γ. Conversely, recombinant SIET, previously designated as S. intermedius exfoliative toxin, did not cause intraepidermal splitting or degradation of any Dsgs. These findings indicate that EXI has a proteolytic activity that digests canine Dsg1, and this characteristic might be involved in the pathogenesis of intraepidermal splitting in canine impetigo.

Isolation of Fusarium sp. from a claw of a dog with onychomycosis.

An 8-year-old male Golden Retriever had lameness and claw abnormality in the second digit of the left forelimb. Radiography revealed osteomyelitis in the distal phalanx bone of the affected limb. Microscopic examination of the claw revealed numerous hyphae in the claw matrix. Fungal DNA fragments coding the ribosomal internal transcribed spacer region (ITS) were detected from the claw matrix as well as fungal colonies of the clinical isolates by PCR. Nucleotide sequencing revealed that the amplicons shared > 99% homology with Fusarium sp. Therapy including oral itraconazole resulted in regrowth of a new claw, in which no hyphae were detected. To the authors' knowledge, this is the first case report of canine onychomycosis in which Fusarium sp. was isolated from the affected claw.

Two dogs with juvenile-onset skin diseases with involvement of extremities.

Two dogs of juvenile-onset skin diseases with involvement of extremities were examined by histopathological, immunohistochemical and ultrastructural analyses. Clinically, both cases showed alopecia and crusts on the face and extremities. Case 1 showed histopathology of dermo-epidermal separation. Ultrastructural analysis revealed that the clefts were recognized between hemidesmosomes and lamina densa. In case 2, histopathology showed follicular atrophy, vacuolar degeneration at lower epidermis and masseter muscle degeneration, without remarkable ultrastructural abnormalities in basement membrane zone of the skin. Thus, the findings in case 1 were compatible to those in junctional epidermolysis bullosa, while those in case 2 were compatible to dermatomyositis-like disease. Combination of histopathological and ultrastructural analyses was useful to distinguish the diseases in two dogs.

The first case of feline Prototheca wickerhamii infection in Japan.

A 3-year-old castrated male domestic short-haired cat was presented with nodules on the left nasal wing and the left earflap. Prototheca cells were found after excision biopsy of one of the nodules located on the left earflap. The patient cat was generally in good condition without skin problems. Prototheca wickerhamii was isolated from all 6 masses after they were surgically nucleated. The cat was recovered two months after intervention with no recurrence of skin nodules. This report deals with the first case of feline protothecosis in Japan.

Cutaneous nocardiosis in a cat.

A 4-year-old spayed female domestic shorthair cat was presented to us for swelling of all foot pads. The skin lesions were histopathologically diagnosed as suppurative pyogranulomatous panniculitis. The lesions did not respond to cephalexin, prednisolone or itraconazole. However, complete resolution of the skin lesions was obtained with doxycycline. A littermate living in the same household developed similar skin lesions that were also successfully treated with doxycycline. Polymerase chain reaction analysis detected the 16S ribosomal RNA gene of Nocardia spp. in DNA extracted from lesion pus, and direct nucleotide sequencing analysis revealed 100% homology with Nocardia elegans. We diagnosed this case as nocardiosis.

Fibrodysplasia ossificans progressiva in a Maine Coon cat with prominent ossification in dorsal muscle.

A one-year and six-month-old female Maine Coon cat presented with skin problems and paravertebral induration with a history of seven months. Survey radiographs and computed tomography revealed prominent calcifications in both sides of cervical, thoracic and lumbar vertebrae and soft tissue in femoral regions, below knee regions and in brachial regions. Histopathological findings from muscle biopsy samples showed connective tissue proliferation around adjacent skeletal muscle, cartilage formation and endochondral ossification. On the basis of these findings, this feline patient was diagnosed with fibrodysplasia ossificans progressiva (FOP). The most prominent signs observed in this FOP case were significant calcifications of dorsal muscle and presentation of cutaneous signs at the early stage.

Neutrophils contact to plasma membrane of keratinocytes including desmosomal structures in canine pemphigus foliaceus.

Pemphigus foliaceus (PF) is an autoimmune blistering skin disease that affects certain mammals including dogs. In canine PF, neutrophils are infiltrated intensely into pustular lesions including acantholytic cells, although neutrophilic infiltration is not characterized in human PF. The roles of the neutrophils in the cutaneous lesions of canine PF have not yet been understood. The purpose of this study was to characterize the ultrastructural features underlying the acantholysis with pustule formation in canine PF. Four dogs diagnosed as PF on the basis of clinical signs, histopathological findings, and direct and indirect immunofluorescence examinations were performed. Electron microscopy revealed that the acantholytic cells were adjacent to multiple neutrophils in the pustules. At the contact points between neutrophils and acantholytic keratinocytes, half-desmosomes of acantholytic keratinocytes with intact attachment plaques were observed within invaginations of neutrophils. Furthermore, on the surface of acantholytic cells in the pustules, neutrophil granules seemed to be secreted to the surface of acantholytic cells and to degenerate the half-desmosome structures. Neutrophils were also observed within the epidermis adjacent to the pustule. At the intercellular gap between two dissociated keratinocytes, neutrophils inserted its pseudopodia into the gap between the two half-desmosomes of keratinocytes. These findings taken together suggested that, at least in the areas where we analyzed ultrastructurally, neutrophils contact desmosomal structures and seem to play some parts in separation of keratinocytes and degeneration of split-desmosomes in pustules of dogs with PF.

Successful treatment of two dogs with allergic dermatitis by anti-allergic peptides (MS-antigen).

The effects of non-specific immunotherapy with anti-allergic peptides extracted from the urine of human allergic patients (MS-antigen), in two dogs with allergic dermatitis (AD) have been described. Clinically, severe pruritus accompanied by secondary bacterial pyoderma did not respond to conventional therapy with systemic antibiotics. The first clinical change appeared as a significant reduction in pruritus within 3 months, around the time of the 15th injection in both cases. The clinical condition was stabilized after 5 months, allowing the gradual withdrawal of concurrent therapies and an increase of injection intervals. The correlation between the results of intradermal skin tests before and after treatment and the improvement of clinical signs was not obvious.