Clinical features of early recurrence of type I thoracolumbar intervertebral disk herniation in Miniature Dachshunds.

Some reports have been published on clinical features in dogs with early recurrence of type I thoracolumbar intervertebral disk herniation (TL-IVDH), but there is little understanding of the changes involved. This retrospective study describes the clinical features, including radiographic image results at the time of recurrence, of dogs with type I TL-IVDH that had undergone hemilaminectomy but then suffered early recurrence. Our medical records were searched between June 2007 and December 2022. Nine dogs showed deterioration in neurological signs within 4 to 6 weeks after surgery. All nine were Miniature Dachshunds. Radiographic images at initial onset showed calcification at the affected intervertebral disk space in all 9 dogs. Disk herniations at the initial onset were located between T11-12 and L1-2. After the first surgery, neurological function improved in all dogs. Recurrence occurred at the same site as at initial onset in all dogs. No calcification was observed at the affected intervertebral disk space on images at the time of recurrence. The extruded disk materials were surgically removed, and neurological function improved after the second surgery. In conclusion, calcification at the affected disk space at the time of initial onset is indicative of residual nucleus materials not yet fully extruded, and is a risk factor for early recurrence of type I TL-IVDH.

Experimental probing of dynamic self-organized columnar assemblies in colloidal liquid crystals.

Self-organized supramolecular assemblies are widespread in nature and technology in the form of liquid crystals, colloids, and gels. The reversible nature of non-covalent bonding leads to dynamic functions such as stimuli-responsive switching and self-healing, which are unachievable from an isolated molecule. However, multiple intermolecular interactions generate diverse conformational and configurational molecular motions over various time scales in their self-assembled states, and their specific dynamics remains unclear. In the present study, we have experimentally unveiled the static structures and dynamical behaviors in columnar colloidal liquid crystals by a coherent X-ray scattering technique using refined model samples. We have found that controlling the size distribution of the colloidal nanoplates dramatically changed their static and dynamic properties. Furthermore, the resulting dynamical behaviors obtained by X-ray photon correlation spectroscopy have been successfully decomposed into multiple distinct modes, allowing us to explore the dynamical origin in the colloidal liquid-crystalline state. The present approaches using a columnar liquid crystal may contribute to a better understanding of the dynamic nature of molecular assemblies and dense colloidal systems and bring valuable insights into rational design of functional properties of self-assembled materials such as stimuli-responsive liquid crystals, self-healing gels, and colloidal crystals. For these materials, the motion of constituent particles and molecules in the self-assembled state is a key factor for structural formation and dynamically responsive performance.

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation.

OBJECTIVE: To assess whether the volume of extruded materials is correlated with neurologic severity in dogs with type I thoracolumbar intervertebral disk herniation (TL-IVDH). ANIMALS: 70 client-owned small-breed dogs with type I TL-IVDH diagnosed between July 1, 2016, and June 30, 2018. PROCEDURES: For this retrospective cohort study, the medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed. The volume and height of the intervertebral disk and the area of the maximal transverse compressed spinal cord were measured using CT myelographic images. For each dog, the volume of the disk immediately cranial to the herniated disk was an internal control. Dogs were grouped on the basis of grade of neurologic severity. RESULTS: Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs. The total volume of the affected intervertebral disks was significantly larger than the internal control. Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity. CLINICAL RELEVANCE: Our findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity.

Biomineral-Inspired Colloidal Liquid Crystals: From Assembly of Hybrids Comprising Inorganic Nanocrystals and Organic Polymer Components to Their Functionalization.

Bioinspired organic/inorganic synthetic composites have been studied as high-performance and functional materials. In nature, biominerals such as pearls, teeth, and bones are self-organized organic/inorganic composites. The inorganic components are composed of calcium carbonate (CaCO3) and hydroxyapatite (HAp), while the organic components consist of peptides and polysaccharides. These composites are used as structural materials in hard biological tissues. Biominerals do not show significantly higher performances than synthetic composites such as glass-fiber- or carbon-fiber-reinforced plastics. However, biominerals consist of environmentally friendly and biocompatible components that are prepared under mild conditions. Moreover, they form elaborate nanostructures and self-organized hierarchical structures. Much can be learned about material design from these biomineral-based hierarchical and nanostructured composites to assist in the preparation of functional materials.Inspired by these biological hard tissues, we developed nanostructured thin films and bulk hybrid crystals through the self-organization of organic polymers and inorganic crystals of CaCO3 or HAp. In biomineralization, the combination of insoluble components and soluble acidic macromolecules controls the crystallization process. We have shown that poly(acrylic acid) (PAA) or acidic peptides called polymer additives induce the formation of thin film crystals of CaCO3 or HAp by cooperation with insoluble organic templates such as chitin and synthetic polymers bearing the OH group. Moreover, we recently developed CaCO3- and HAp-based nanostructured particles with rod and disk shapes. These were obtained in aqueous media using a macromolecular acidic additive, PAA, without using insoluble polymer templates. At appropriate concentrations, the anisotropic particles self-assembled and formed colloidal liquid-crystalline (LC) phases.LC materials are generally composed of organic molecules. They show ordered and mobile states. The addition of stimuli-responsive properties to organic rod-like LC molecules led to the successful development of informational displays, which are now widely used. On the other hand, colloidal liquid crystals are colloidal self-assembled dispersions of anisotropic organic and inorganic nano- and micro-objects. For example, polysaccharide whiskers, clay nanosheets, gibbsite plate-shaped particles, and silica rod-shaped particles exhibit colloidal LC states.In this Account, we focused on the material design and hierarchical aspects of biomineral-based colloidal LC polymer/inorganic composites. We describe the design and preparation, nanostructures, and self-assembled behavior of these new bioinspired and biocompatible self-organized materials. The characterization results for these self-assembled nanostructured colloidal liquid crystals found using high-resolution transmission electron microscopy, small-angle X-ray scattering, and neutron scattering and rheological measurements are also reported. The functions of these biomineral-inspired liquid crystals are presented. Because these biomineral-based LC colloidal liquid crystals can be prepared under mild and aqueous conditions and they consist of environmentally friendly and biocompatible components, new functions are expected for these materials.

Shear-induced liquid-crystalline phase transition behaviour of colloidal solutions of hydroxyapatite nanorod composites.

Liquid-crystalline (LC) bio-inspired materials based on colloidal nanoparticles with anisotropic morphologies such as sheets, plates, rods and fibers were used as functional materials. They show stimuli-responsive behaviour under mechanical force and in electric and magnetic fields. Understanding the effects of external stimuli on the structures of anisotropic colloidal particles is important for the development of highly ordered structures. Recently, we have developed stimuli-responsive hydroxyapatite (HAP)-based colloidal LC nanorods that are environmentally-friendly functional materials. In the present study, the ordering behaviour of HAP nanorod dispersions, which show LC states, has been examined using in situ small-angle neutron scattering and rheological measurements (Rheo-SANS) under shearing force. The structural analyses and dynamic viscosity observations provided detailed information about the effects of shear force on the structural changes of HAP nanorods in D2O dispersion. The present Rheo-SANS measurements unraveled three kinds of main effects of the shear force: the enhancement of interactions between the HAP nanorods, the alignment of HAP nanorods to the shear flow direction, and the formation and disruption of HAP nanorod assemblies. Simultaneous analyses of dynamic viscosity and structural changes revealed that the HAP nanorod dispersions exhibited distinctive rheological properties accompanied by their ordered structural changes.

Bioinspired selective synthesis of liquid-crystalline nanocomposites: formation of calcium carbonate-based composite nanodisks and nanorods.

Here we report new organic/inorganic hybrid colloidal liquid crystals that consist of colloidal calcium carbonate (CaCO3)/poly(acrylic acid) (PAA) hybrid nanodisks. We selectively synthesized anisotropic liquid-crystalline CaCO3-based nanodisk and nanorod composites in water/methanol mixtures, which formed discotic and calamitic nematic liquid crystals in their colloidal dispersions, respectively. The vaterite nanodisks and calcite nanorods were selectively synthesized in methanol-rich and water-rich solutions, respectively. The observation of these materials with transmission electron microscopy clarified the atomic-scale structures of these nanodisks and nanorods, revealing the self-organized CaCO3/PAA hybrid structures with the ability to form colloidal liquid crystals. The liquid crystals were prepared under mild and aqueous conditions by methods using acidic polymers inspired by the biomineralization process. The present approach provides new insights into the design of organic/inorganic hybrid colloidal liquid crystals and development of environmentally friendly functional hybrid materials.

Liquid-Crystalline Hydroxyapatite/Polymer Nanorod Hybrids: Potential Bioplatform for Photodynamic Therapy and Cellular Scaffolds.

Recently, we found that self-organization of hydroxyapatite (HAp) with poly(acrylic acid) (PAA) leads to the formation of liquid-crystalline (LC) nanorod hybrids that form aligned films and show stimuli-responsive properties. Here, we demonstrate that these biocompatible HAp/PAA hybrid nanorods represent a platform technology as drug nanocarriers for photodynamic cancer therapy and as bioscaffolds for the control of cellular alignment and growth. To use hybrid nanorods as a drug nanocarrier, we introduced methylene blue (MB), a typical photosensitizer for photodynamic therapy, into the PAA nanolayer covering the surface of the HAp nanocrystals through electrostatic interactions. The stable MB-loaded HAp/PAA hybrid nanorods efficiently produced singlet oxygen from MB upon light irradiation and showed remarkable photodynamic therapeutic effects in cancer cells. Moreover, taking advantage of the mechanically responsive LC alignment properties of the HAp/PAA hybrid nanorods, macroscopically oriented bioscaffolds were prepared through a spin-coating process. The cells cultured on the oriented scaffolds showed cellular alignment and elongation along the oriented direction of the hybrid nanorods. The HAp/PAA hybrid nanorods demonstrate potential in drug delivery and tissue engineering. These unique LC HAp/PAA hybrid nanorods have significant potential as a platform for the development of various types of biomaterial.

Static structure and dynamical behavior of colloidal liquid crystals consisting of hydroxyapatite-based nanorod hybrids.

Biominerals such as bones and teeth have elaborate nanostructures composed of aligned anisotropic hydroxyapatite (HAp) nanocrystals, which results in excellent mechanical properties. Construction of such ordered structures of HAp nanocrystals in synthetic materials is challenging. Recently, we reported that HAp-nanorod-based colloidal liquid crystals could be obtained. In the present study, the static structure and dynamics of liquid-crystalline (LC) colloidal dispersions of HAp nanorods are investigated by using small-angle X-ray scattering (SAXS) and X-ray photon correlation spectroscopy (XPCS). The SAXS results reveal that the interparticle distance decreases with increasing HAp concentration, φHAp, and the decrease of the interparticle distance for the short-axis direction is significantly smaller in the LC phase than the interparticle distance in the isotropic phase. In the dynamical studies of the LC phase using XPCS, we observe the diffusive motion of the HAp colloids, with the diffusion coefficient being dependent on the wave number. The diffusive motion slows down with increasing φHAp. We observe anisotropic dynamics after long-term storage (160 days after sealing), whereas only isotropic dynamics are observed in the initial XPCS measurements after short-term storage (14 days after sealing). Moreover, we have found that the dynamics slows down with increasing storage time.

Stimuli-responsive hydroxyapatite liquid crystal with macroscopically controllable ordering and magneto-optical functions.

Liquid crystals are mostly formed by self-assembly of organic molecules. In contrast, inorganic materials available as liquid crystals are limited. Here we report the development of liquid-crystalline (LC) hydroxyapatite (HAp), which is an environmentally friendly and biocompatible biomineral. Its alignment behavior, magneto-optical properties, and atomic-scale structures are described. We successfully induce LC properties into aqueous colloidal dispersions of rod-shaped HAp by controlling the morphology of the material using acidic macromolecules. These LC HAp nanorod materials are macroscopically oriented in response to external magnetic fields and mechanical forces. We achieve magnetic modulation of the optical transmission by dynamic control of the LC order. Atomic-scale observations using transmission electron microscopy show the self-organized inorganic/organic hybrid structures of mesogenic nanorods. HAp liquid crystals have potential as bio-friendly functional materials because of their facile preparation, the bio-friendliness of HAp, and the stimuli-responsive properties of these colloidal ordered fluids.

Methylprednisolone sodium succinate reduces spinal cord swelling but does not affect recovery of dogs with surgically treated thoracolumbar intervertebral disk herniation.

The effect of methylprednisolone sodium succinate (MPSS) therapy was studied in 50 dogs with surgically treated Hansen type I thoracolumbar intervertebral disk herniation (TL-IVDH). Administration of MPSS significantly reduced the swelling of the spinal cord. The sensitivity of localization of disk extrusion using myelography in the MPSS group was 92.3%, and in the non-administration group was 83.3%. No significant difference in recovery rate or length of recovery time was found between the two groups. Administration of MPSS reduced spinal cord swelling, but has no effect on recovery in dogs after surgery for TL-IVDH.

Liquid-crystalline calcium carbonate: biomimetic synthesis and alignment of nanorod calcite.

Liquid-crystalline CaCO3 has been prepared for the first time. The nanorods of CaCO3 calcite are obtained by bio-inspired crystallization through aqueous colloidal precursors of amorphous CaCO3 stabilized by poly(acrylic acid). The synthesized calcite nanocrystals have well-tuned morphologies that are preferable for formation of liquid-crystalline phases in concentrated aqueous colloidal solution. The one-dimensional alignment of calcite crystals is achieved by mechanical shearing of the aqueous colloidal solution showing liquid-crystalline phases. These CaCO3-based liquid crystals formed by a self-organization process in mild conditions may have great potential for use as environmentally friendly materials.

Evaluation of serum phosphorylated neurofilament subunit NF-H as a prognostic biomarker in dogs with thoracolumbar intervertebral disc herniation.

OBJECTIVE: To investigate whether pNF-H is a prognostic biomarker of spinal cord injury (SCI) in paraplegic dogs with thoracolumbar intervertebral disc herniation (IVDH). STUDY DESIGN: Prospective, case-control clinical study ANIMALS: Dogs (n = 60) with SCI from IVDH and 6 healthy dogs. METHODS: Serum from 60 thoracolumbar IVDH dogs (Grade 4: 22 dogs; Grade 5: 38 dogs) collected 1-3 days after injury, and 6 control dogs, was analyzed using enzyme-linked immunosorbent assay (ELISA) against a phosphorylated form of the high-molecular-weight neurofilament subunit NF-H (pNF-H). Serum pNF-H levels were compared between different IVDH grades and their prognostic value was investigated. RESULTS: pNF-H levels were significantly greater in Grade 5 than Grade 4 dogs. There were significant differences in pNF-H levels between dogs that regained voluntarily ambulation and those that did not. All 8 dogs that had high pNF-H levels 1-3 days after injury did not regain the ability to walk after surgery. CONCLUSIONS: Serum pNF-H levels might be a biomarker for predicting prognosis of canine SCI.

A spayed female cat with squamous cell carcinoma in the uterine remnant.

A 7-year-old spayed female domestic short-haired cat presented with dysuria and hematuria that had been unresponsive to medical therapy. Imaging tests such as ultrasonography, urethrocystography and computed tomography revealed a pelvic mass compressing the urethra. Based on histological examination of the mass following surgical resection, the cat was diagnosed squamous cell carcinoma (SCC) derived from the uterine remnant. After surgery, dysuria was resolved, but on instead, urine and fecal incontinence were observed. Then, about four months after surgery, recurrence of the mass and the symptoms was observed. Consequently, the cat was ultimately euthanized. This is the first report of SCC arising from the uterine remnant in a spayed female cat.

Evaluation of methods for cell harvesting and the biological properties at successive passages of canine bone marrow stromal cells.

OBJECTIVE: To compare methods for harvesting canine bone marrow stromal cells (BMSCs) and determine the biological properties of canine BMSCs at successive passages in vitro. SAMPLE: BMSCs collected from the femurs of 9 Beagles. PROCEDURES: A fibroblast assay was performed to compare 2 methods for harvesting BMSCs: the aspiration and perfusion method. Flow cytometric analysis was performed to evaluate the cell surface markers. Changes in proliferative activity were analyzed by examining radioactivity of hydrogen 3-thymidine. Cell senescence was studied via senescence-associated ß-galactosidase staining, and differentiation properties (osteogenesis and adipogenesis) were estimated in association with passage. RESULTS: The aspiration method yielded significantly more fibroblasts than the perfusion method. The cells harvested by both methods gave positive results for CD44 and CD90 and negative results for CD34 and CD45. After induction, the cells had osteogenic and adipogenic phenotypes. The biological properties of BMSCs harvested by the aspiration method were estimated in association with passage. With increasing number of passages, the proliferative activity was reduced and the proportion of cells with senescence-associated ß-galactosidase staining was increased. The capacity of differentiation was reduced at passage 3. CONCLUSIONS AND CLINICAL RELEVANCE: The aspiration method was superior for collection of BMSCs. In early passages, canine BMSCs had the proliferative activity and potential of osteogenic and adipogenic differentiation, but this decreased with increased number of passages. Consideration of passage will be important to the success of any strategy that seeks to regenerate tissue though the use of BMSCs.

Safety of autologous bone marrow stromal cell transplantation in dogs with acute spinal cord injury.

OBJECTIVE: To assess the feasibility and safety of transplantation of autologous bone marrow stromal cell (BMSC) in dogs with acute spinal cord injury (SCI). STUDY DESIGN: An open-label single-arm trial. ANIMALS: Dogs (n = 7) with severe SCI from T6 to L5, caused by vertebral fracture and luxation. METHODS: Decompressive and stabilization surgery was performed on dogs with severe SCI caused by vertebral fracture and luxation. Autologous BMSCs were obtained from each dog's femur, cultured, and then injected into the lesion in the acute stage. Adverse events and motor and sensory function were observed for >1 year after SCI. RESULTS: Follow-up was 29-62 months after SCI. No complications (eg, infection, neuropathic pain, worsening of neurologic function) were observed. Two dogs walked without support, but none of the 7 dogs had any change in sensory function. CONCLUSIONS: Autologous BMSC transplantation is feasible and safe in dogs with acute SCI. Further studies are needed to determine the efficacy of this therapy.

Three cases of idiopathic sterile pyogranulomatous inflammation of epidural fat in Miniature Dachshunds.

Progressive ataxia and paralysis in three Miniature Dachshunds were found to be caused by idiopathic sterile pyogranulomatous inflammation of epidural fat between T5 and L4. All dogs were managed by hemilaminectomy and removal of epidural compressive material. Surgical findings and histopathological evaluation were necessary to diagnose epidural pyogranulomatous inflammation. A dog did not regain motor and sensor function after the surgery. Two dogs had exhibited improved neurological function after the surgery, but they recurred. Oral cyclosporine treatment was useful for their long remission. Idiopathic sterile pyogranulomatous inflammation of epidural fat can be considered to be a cause of thoracolumbar myelopathy in dogs.

Evaluation of transplantation of autologous bone marrow stromal cells into the cerebrospinal fluid for treatment of chronic spinal cord injury in dogs.

OBJECTIVE: To evaluate effects of transplantation of bone marrow stromal cells (BMSCs) into the CSF for the treatment of chronic spinal cord injury in dogs that had not responded by 1 month after decompressive surgery. ANIMALS: 23 dogs. PROCEDURES: Dogs with paraplegia and loss of nociception in the pelvic limbs for at least 1 month after decompressive surgery were assigned to transplantation or control groups. Dogs in the transplantation group received BMSCs injected into the CSF 1 to 3 months after decompressive surgery. Dogs in the control group did not receive additional treatments. Improvements in gait, proprioceptive positioning, and nociception were evaluated by use of the Texas Spinal Cord Injury Scale for ≥ 6 months after BMSC transplantation. RESULTS: 6 of 10 dogs in the transplantation group regained the ability to walk, whereas only 2 of 13 dogs in the control group regained the ability to walk. Scores for the Texas Spinal Cord Injury Scale in the transplantation group were significantly higher than scores in the control group at the endpoint of the study (6 months after BMSC transplantation or after decompressive surgery for the transplantation and control groups, respectively). Only 1 dog (transplantation group) recovered nociception. All dogs from both groups had fecal and urinary incontinence. No complications were observed in relation to BMSC transplantation. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of BMSCs into the CSF caused no complications and could have beneficial effects on pelvic limb locomotion in dogs with chronic spinal cord injuries.

Acute myelomonocytic leukemia (AML-M4) in a dog with the extradural lesion.

A two-year-old dog having presented with neurological signs showed marked leukocytosis and appearance of blast cells in the peripheral blood. Hematological and bone marrow examination showed an increase in blasts having both myeloid and monocytic cells characteristics. The dog was diagnosed with acute myelomonocytic leukemia (AML-M4) on the basis of bone marrow findings. Although the dog was treated with a multi-combination chemotherapy, the neurological abnormalities progressed and the dog was euthanized. Myelographic examination and necropsy revealed the extradural lesion formed by AML-M4 around the cervical spinal cord and this lesion was considered as a cause of the neurological signs.

Inflammatory reaction in the herniated degenerative disc materials in miniature dachshunds.

Histological and immunohistochemical studies were conducted using herniated intervertebral disc materials obtained surgically from 39 miniature dachshunds. Infiltration of inflammatory cells, such as macrophages, neutrophils, T or B lymphocytes, and multinucleated giant cells, were identified in intervertebral disc materials in 23 cases. Furthermore, proliferations of connective tissue, including neovascularization, were also observed in 17 cases. These results suggest that spontaneous regression of herniated intervertebral disc material could occur in affected dogs.

Rectification of width and area of the ciliary cleft in dogs.

The width and area of the ciliary cleft (CCW and CCA) according to ultrasound biomicroscopy was rectified to compare dogs of different body sizes/weights, including toy breed (TBG), small breed (SBG), medium breed (MBG) and large/giant breed groups (LGBG). A linear correlation was detected between the natural log of body weight and the ocular axial length (OAL) reflecting the ocular size (OS; r=0.81, p<0.001). A significant positive correlation was found between OAL and the distance of the Schwalbe's line to the anterior lenticular capsule (SLD; r=0.87, p<0.001), suggesting that SLD could rectify canine OS. Rectified CCW (r-CCW) and CCA (r-CCA) were calculated using SLD and fixed SLD as the SLD mean (SLDM). The SLDM was 2.55 mm in this study, and r-CCW and r-CCA were calculated as r-CCW = CCW x (2.55/SLD) and r-CCA = CCA x (2.55/SLD)(2). The CCW values of TBG, SBG and MBG were narrower than those of LGBG (p<0.05). There were significant statistical differences in CCA between all groups other than TBG and SBG (p<0.05). There were no significant differences in r-CCW and r-CCA in any of the groups. In addition, CCW/SLD did not show significant changes in dogs with different body sizes/weights. These results suggested that r-CCW, r-CCA and CCW/SLD can be used for comparison between dogs of different body sizes/weights.