Original Lamina Research Articles

Individualized artificial titanium alloy spinal lamina with 3D printing technology

Background: Laminectomy and decompression is a common procedure for treating spine diseases. However, due to the lack of a posterior, bony braced structure, the dural sac and nerve roots can adhere to the surrounding tissues, and scar formation can occur in muscle and soft tissues. This can cause new compression post surgery, and failure of the operation. Objective: This study aimed to produce an individualized titanium alloy spine lamina using 3D printing technology, and to evaluate its effectiveness by implantation in human cadaveric spines. Methods: Six adult lumbar cadaver specimens were used, and computed tomography (CT) was used to obtain DICOM medical digital image standard data. The lumbar vertebrae structure was reconstructed by three-dimensional (3D) modeling software, and then simulated lumbar laminectomy was performed. Based on the characteristics of the original lamina, an artificial spine lamina was designed, including suture holes at the posterior ligament attachment point and a locking screw hole for fixation. A titanium alloy spine lamina was fabricated by 3D printing, and a guide plate to assist artificial lamina implantation was designed. Using the guide plated, L4 lumbar vertebrae segment laminectomy was performed on the 6 lumbar spine specimens, titanium alloy spine lamina were implanted and fixed with cortical bone trajectory screws. After implantation, CT was performed to record the length of the screw, the trajectory of the screw in the pedicle, and changes of bony spinal canal volume and anteroposterior diameter of the spinal canal. Results: The morphology of artificial spine lamina matched that of the original lamina. The artificial lamina was easy to implant, and matched the original lamina. The laminas were fixed by 12 cortical screws (diameter, 4.5 mm; median length, 34.67 ± 1.97 mm). CT scan indicated that all screws passed through the pedicle cortex by < 2 mm (2 screws penetrated the inner wall). The bony canal volume of the L4 vertebral pedicle was 311.23 ± 38.17 mm2 before operation and 356.17 ± 43.11 mm2 after operation, and there was statistical difference (P < 0.001). The anteroposterior diameter of spinal canal was 17.82 ± 2.03 mm before surgery and 20.67 ± 2.38 mm after surgery, and they were statistically different (P < 0.001). Conclusion: An individualized artificial titanium alloy spine lamina designed and produced with 3D printing technology can be used to reconstruct the structure of the posterior spine complex after lumbar laminectomy. The artificial lamina can increase the volume of the spinal canal and provide a posterior ligament reconstruction attachment point.

Synaptic Properties of Corticocortical Connections between the Primary and Secondary Visual Cortical Areas in the Mouse

Despite the importance of corticocortical connections, few published studies have investigated the functional, synaptic properties of such connections in any species, because most studies have been purely anatomical or aimed at functional features other than synaptic properties. We recently published a study of synaptic properties of connections between the primary and secondary cortical auditory areas in brain slices from the mouse, and, in the present study, we aimed to extend this by performing analogous studies of the primary and secondary visual areas (V1 and V2). We found effectively the same results. That is, connections between V1 and V2 in both directions were quite similar; in each case, the glutamatergic inputs could be classified as one of two types, Class 1B (formerly "driver") and Class 2 (formerly "modulator"). There is a clear laminar correlation for these different inputs, in terms of both the laminae of origin and those in which the recorded cells were located. Our data suggest a common pattern to the functional organization of corticocortical connectivity in the mouse cortex.

The pattern of invasion of early carcinomas in Barrett's esophagus is dependent on the depth of infiltration

The differential diagnosis “high-grade intraepithelial neoplasia” or “well-differentiated Barrett's adenocarcinoma limited to the mucosa” is controversial. We investigated 277 endoscopically resected specimens of early Barrett's carcinoma. Depth of infiltration was classified as follows: m 1=carcinoma limited to Barrett's mucosa; m 2=carcinoma infiltrating the neo-muscularis mucosae; m 3=infiltration of the original lamina propria of the esophageal mucosa; m 4=infiltration of the original muscularis mucosae; sm 1, sm 2, and sm 3=infiltration into the upper third, middle third, and lower third of the submucosa. The pattern of invasion was classified and graded as follows: tubular (D 0)=only neoplastic tubuli showing cytologic criteria of malignancy – no tumor cell dissociation; dissociation grade 1 (D 1)=few dissociated tumor cells; D 2=moderate amount of dissociated tumor cells; D 3=pronounced tumor cell dissociation. 74–96% of m 1–m 4 Barrett's carcinomas limited to the mucosa have a D 0-pattern. Tubular invasion decreases only when the submucosa has been infiltrated (sm 1: 70.4%, sm 2: 30.0%, sm 3: 24.0%). Our study shows that the pattern of invasion in early cancer in Barrett's esophagus statistically significantly depends on depth of infiltration.

Evaluation of Debonding of Lamina from Foam and Repairs to Exterior Insulation and Finish System Façade

Abstract A large building in Denver, Colorado was constructed in 1999 with exterior insulation and finish system (EIFS) cladding. About a year after completion, the lamina started to debond from the foam on the darker-colored EIFS panels. Tests were conducted to determine the cause of the delamination. The influence of solar radiation was studied. Although elevated temperatures were measured in these areas, they were not above the “melting point” of the foam insulation. During the investigation it was discovered that the pattern of the fiberglass mesh appeared to be “embossed” in the foam surface. Microscopic examination confirmed that the surface of the foam had been locally dissolved in the pattern of the mesh. Chemical analysis and exposure tests performed on the fiberglass mesh used in the lamina revealed that plasticizers migrating from the mesh would attack the interface surface of the foam insulation at elevated temperatures that are below the typical melting point of the foam. The elevated surface temperatures of the darker-colored panels appeared to accelerate the effect of the plasticizers. The scope of repairs at the darker-colored EIFS included removal of the original lamina, preparation of the foam, and installation of new lamina. The mesh used in the new lamina was analyzed to ensure that it did not contain plasticizers capable of dissolving the foam. The lighter-colored EIFS had not exhibited widespread delamination of the lamina. However, the risk of migration of the plasticizers and the potential for future delamination still existed. Mechanical-fastening was used to secure the original lamina to the framing, then a new lamina was applied over the original lamina. This repair concept was dependent on proper bond between the new and original laminas. The bond was tested using techniques similar to those used for measuring adhesion for both new synthetic and cementitious base coat materials.

Sedimentation Equilibrium-Quantitative Polyacrylamide Gel Electrophoresis (SE-QPAGE): A New Technique for the Detection of Associations in Multicomponent Solutions

A new technique for the characterization of self- and hetero-associations in multicomponent solutions without chemical modification of the salutes is described. Solutions containing between one and four distinct protein components were first centrifuged to sedimentation equilibrium in swinging bucket rotors. Following centrifugation, the contents of each centrifuge tube were fractionated into 3-μl aliquots deriving from sequential laminae of solution, and each aliquot was diluted into sodium dodecyl sulfate-containing buffer. Following incubation, 20 μl of each aliquot was applied to individual lanes of a polyacrylamide gel. Following electrophoresis, proteins on the gel were stained with Coomassie blue R-250. The pattern of stained bands on the gel was digitized and the resulting image file analyzed to yield relative intensities of individual bands. A quantitative relationship between band intensity and amount of protein in a band was established by means of calibration gels. This relationship was found to be essentially constant for a variety of different proteins except for a protein-dependent scaling factor. Analysis of the dependence of band intensity of a single protein component upon the radial position of the original lamina from which the fraction was derived yielded reliable estimates of the molecular weight of that component in the original solution and in some cases showed that two components were cosedimenting as a complex.

Ascending tract neurons survive spinal cord transection in the neonatal rat

Retrograde axonal transport was used to determine which ascending nerve tracts from the lumbosacral spinal cord are present in the cervical spinal cord of the newborn rat and if their cell bodies survive axotomy. A pledget of true blue was applied to a low cervical spinal transection in the newborn rat ( N = 4). After a 5-day survival period, neurons were labeled in the laminae of origin of all ascending nerve tracts throughout the lumbosacral spinal cord. Neurons labeled in the same way survived for at least 1 month postoperatively when the spinal cord was transected at a midthoracic level at 5 days of age ( N = 4). No neurons in the lumbosacral spinal cord were labeled if the midthoracic spinal cord was transected at the same time as application of the dye to cervical spinal cord ( N = 2). Therefore, neurons labeled with true blue from cervical spinal cord during the neonatal period are likely to have been axotomized by thoracic injury made at 5 days of age. Three months after midthoracic spinal transection of newborn rats, HRP was injected or a pledget was applied to the first spinal segment caudal to this lesion ( N = 8). The same population of neurons was labeled as in adult rats receiving application of HRP to an acute midthoracic spinal transection ( N = 4). Neurons were seldom labeled in adult rats in which HRP was injected and ascending nerve tract axons not damaged ( N = 4). These results suggest that most ascending nerve tract axons are present in cervical spinal cord during the neonatal period (by 4 to 5 days of age). A substantial number of these neurons survive neonatal midthoracic spinal transection and their axon terminals remain near this lesion site.

Origin of Ooids in Pleistocene Miami Limestone, Florida Keys: ABSTRACT

Scanning electron microscopy reveals that ooids in this marine unit are of biogenic origin in the sense that endolithic and epilithic algae, fungi?, and mucilage played primary roles in constructing laminae in the cortex of each ooid. Three end-member types of original laminae are recognized (1, 2, 3, below); each is made up of fundamental building blocks of aragonite crystals typically shaped like miniature batons. (1) Filaform (common): laminae composed of a network of calcified algal or possibly fungal filaments, or both. Batons in such laminae are typically less than 1 µ long and most are randomly oriented relative to the nucleus. The batons formed within a mucilaginous sheath surrounding the original algae or fungi. Filaments in such laminae could go through lif as epiliths or begin as epiliths that became endoliths which eventually became epiliths once again. (2) Spheroform (rare): laminae composed mainly of calcified spherical bodies of algal or fungal origin. (3) Sheet (common): pavement-like layers of batons that are typically 0.5 to 2.0 µ long and are oriented tangentially relative to the nucleus. Most batons in type (3) laminae originated in a layer of mucilage or mucous that did not surround algae or fungi, but which enveloped all or much of the surface of a developing ooid. Examples of typical sequences of laminae development are (1)-(1)-(1) etc, (3)-(3)-(3) etc, and (1)-(3)-(1)-(3) etc, possibly with a final type (2) lamina. Contrary to evidence from many modern marine aragonite ooids, filamentous algae was not a constructive fact r in the formation of all laminae in the cortex of all ooids in the Miami Limestone. End_of_Article - Last_Page 943------------

Brick-like texture and radial rays in Triassic pisolites of Lombardy, Italy: A clue to distinguish ancient aragonitic pisolites

Triassic pisolites from the Calcare Rosso, Lombardy, Italy, were formed in a hypersaline vadose environment and now show alternating dolomite and calcite laminae. The calcite consists either of microsparite laminae with a brick-like fabric, or of a mass of mosaic crystals with the external form of square-ended rays. These features suggest that the original laminae and rays were aragonitic, like those of the Holocene supratidal pisolites of the Persian Gulf, which consist of alternating laminae of unoriented nannomicrite with Mg-rich mucilaginous material, and aragonitic fibers with radial orientation separated by mucilaginous films. It is suggested that the transformation to brick-like and ray textures passed through the following diagenetic path: (1) original formation of fibrous aragonite laminae; (2) local aggrading recrystallization of aragonite fibers to large square-ended rays during hypersaline phases; (3) dolomitization of Mg-rich mucilaginous nannomicrite laminae during hyposaline phases; (4) inversion of the aragonite fibers and rays to calcite on a piece-by piece basis that preserved the original textural details, when the pH or Mg/Ca ratio dropped. The brick-like and ray fabrics have not been found in laminae of continental freshwater pisolites because these were deposited as equant and stable crystals of low-Mg calcite. These textures consequently make it possible to establish the chemistry of the depositional and early diagenetic milieu for some ancient pisolitic rocks.

Terminal arborizations of retinotectal axons in the bullfrog.

AbstractIn the optic tectum of Rana catesbeiana four laminae of myelinated fibers in the superficial zone of the optic tectum (laminae B, D, F, and G: Potter, ′69) are identified as retinal axons on evidence from patterns of degeneration following contralateral eye removal. After survival times of 5 to 22 days Cajal's block method II shows either fragmentation or abnormal beading of the axons in the four laminae and the paraffin‐Nauta method shows coarse granules, representing axonal debris, in these laminae.Golgi impregnations of terminal arborizations arising from fibers in laminae B, D, F, and G show three major types of branching patterns. The arbors are horizontally flattened and are elongated in the same direction as the parent fibers. Densely branched (DB) arbors have stem fibers in laminae B and D and are distributed within the same and adjacent laminae. Widely branched (WB) and thin, straight (TB) arbors have stem fibers in laminae F and G and are distributed mainly in the two laminae of origin with some overlap into adjacent layers of cells and fibers. The horizontal dimensions of DB arbors are 30 μ–70 μ by 100 μ–200 μ, whereas the WB arbors are more variable in overall dimensions. The TB arbors consist of long thin stem axons that give off infrequent terminal specializations in the form of forked or spiny appendages. Numerous terminal forks are present on the WB arbors but are rare on the DB arbors. Swellings and varicosities, that probably represent synaptic specializations, are particularly numerous on the long tertiary branches of DB arbors.

Experimental studies on the formation of the glomerular basement membrane

The glomerular basement membrane of rats was permanently labeled with deposits of silver nitrate ingested in drinking water. After labeling was achieved, silver nitrate ingestion was stopped. Thickening of the basement membranes was effected by normal aging of the rats or by the administration of aminonucleoside which induced chronic nephrosis. In both groups of rats new increments of glomerular basement membrane were free of silver, while the original lamina densa was diffusely and homogenously stippled by silver deposits. The new increments were located on the epithelial side of the basement membrane and were indistinguishable from the labeled portion. These experiments have demonstrated that glomerular basement membrane is a product of the epithelial cells, both in the normal processes of aging and in the pathological processes of aminonucleoside nephrosis.