Analysis of skull bone thickness during growth: an anatomical guide for safe pin placement in halo fixation

PURPOSE

To assess skull bone thickness from birth to skeletal maturity at different sites to provide a reference for the correct selection of pin type and pin placement according to age.

METHODS

270 children and adolescents (age: 0-17 years) with a normal CT scan obtained at Emergency Department for other medical reasons were included. Skull thickness was measured on the axial plane CT scans at eight different sites of the vault: midline anterior (A) and posterior (P), right and left lateral (L), antero-lateral (AL), postero-lateral (PL).

RESULTS

From birth to skeletal maturity, L thickness was increased significantly less (+ 58%) compared with AL (+ 205%), P (+ 233%), PL (+ 247%), and A (+ 269%) thickness (P < 0.01). At the end of growth, the thickest and thinnest points of the vault (absolute value) were found at the P and L measurement sites, respectively (P < 0.01). Children aged < 4 years exhibited the highest variability in AL and PL skull bone thickness, with thickness < 3 mm observed in 85% (64/75 patients) and 92% (69/75 patients) of cases, respectively.

CONCLUSION

We recommend that the tip of the pin should not exceed 2-3 mm in children aged < 4, and 4 mm in children aged 4-6 years, to decrease the risk of inner table perforation. After the age of 7 years and 13 years, standard-sized pin tips (5 and 6 mm, respectively) may be safely used. Children aged < 4 years show significant variability in skull thickness, and therefore a CT scan may be required for this particular age group.

Establishment of a new cell line susceptible to Cyprinid herpesvirus 3 (CyHV-3) and possible latency of CyHV-3 by temperature shift in the cells

A new cell line named CCF-K104 predominantly consisting of fibroblastic cells showed optimal growth at temperatures from 25 °C to 30 °C. Serial morphological changes in the cells induced by Cyprinid herpesvirus 3 (CyHV-3) included cytoplasmic vacuolar formation, cell rounding and detachment. Mature virions were purified from CyHV-3-infected CCF-K104 cells by sucrose gradient ultracentrifugation and had a typical herpesvirus structure on electron microscopy. Infectious CyHV-3 was produced stably in CCF-K104 cells over 30 viral passages. Our findings showed that CCF-K104 is a useful cell line for isolation and productive replication of CyHV-3. A temperature shift from 25 °C to 15 °C or 35 °C did not allow serial morphological changes as observed at 25 °C for 14 days. Under the same conditions, real-time PCR showed that CyHV-3 was present with low viral DNA loads, suggesting that CyHV-3 may establish latent infection in CCF-K104 cells. Amplification of the left and right terminal repeat sequences of the CyHV-3 genome arranged in a head-to-tail manner was detected by nested PCR following an upshift in temperature from 25 °C to 35 °C. The PCR results suggested that the circular genome may represent a latent form of CyHV-3.

The involvement of IL-23 and the Th17 pathway in periodontitis

Interleukin (IL)-23 is an essential cytokine involved in expansion of the Th17 lineage, which is associated with many immune-related destructive tissue diseases. We hypothesized that the IL-23-induced Th17 pathway plays a role in periodontal pathology and examined the expression of cytokines, and related molecules, in periodontal lesions and control sites. IL-23 and IL-12 were expressed at significantly higher levels in periodontal lesions than in control sites. However, the relative expression of the IL-23 receptor compared with the IL-12 receptor beta2 was significantly higher in periodontal lesions. Moreover, IL-17 expression was significantly higher in periodontal lesions, especially in the tissue adjacent to bone destruction, than in control sites. There was no significant difference in the expression levels of IFN-gamma, an important cytokine inhibiting differentiation toward the Th17 pathway, between periodontal lesions and control sites. Together, these results suggest that the IL-23-induced Th17 pathway is stimulated in inflammatory periodontal lesions.

Establishment of graded spinal cord injury model in a nonhuman primate: the common marmoset

Most previous studies on spinal cord injury (SCI) have used rodent models. Direct extrapolation of the results obtained in rodents to clinical cases is difficult, however, because of neurofunctional and anatomic differences between rodents and primates. In the present study, the development of histopathologic changes and functional deficits were assessed quantitatively after mild, moderate, and severe spinal cord contusive injuries in common marmosets. Contusive SCI was induced by dropping one of three different weights (15, 17, or 20 g) at the C5 level from a height of 50 mm. Serial magnetic resonance images showed significant differences in the intramedullary T1 low signal and T2 high signal areas among the three groups. Quantitative histologic analyses revealed that the number of motor neurons, the myelinated areas, and the amounts of corticospinal tract fibers decreased significantly as the injury increased in severity. Motor functions were evaluated using the following tests: original behavioral scoring scale, measurements of spontaneous motor activity, bar grip test, and cage-climbing test. Significant differences in all test results were observed among the three groups. Spontaneous motor activities at 10 weeks after injury were closely correlated with the residual myelinated area at the lesion epicenter. The establishment of a reliable nonhuman primate model for SCI with objective functional evaluation methods should become an essential tool for future SCI treatment studies. Quantitative behavioral and histopathologic analyses enabled three distinct grades of injury severity (15-g, 17-g, and 20-g groups) to be characterized with heavier weights producing more serious injuries, and relatively constant behavioral and histopathologic outcomes.

Effect of organic germanium compound (Ge-132) on experimental osteoporosis in rats

1. The therapeutic effect of organic germanium compound, 2-carboxyethylgermaniumsesquioxide (Ge-132), for experimental osteoporosis was studied using ovariectomized rats maintained on a low calcium containing diet. 2. Serum calcitonin (sCT) level was decreased and serum parathyroid hormone (sPTH) level was increased by ovariectomy and the decrement and increment rates, respectively, were reduced by administration of Ge-132. Thus, the sCT/sPTH ratio was greater in the groups given Ge-132, indicating that the resorption was somehow inhibited by Ge-132. 3. The transverse strength of femur bone was significantly enhanced by Ge-132. 4. A trend was found in the group given Ge-132 for a larger femur cortical bone index. 5. The relative femur bone wet weight was greater in the group given Ge-132. 6. These results indicate that Ge-132 prevents decreased bone strength, and affects the femur cortical bone index, and bone mineral mass caused by osteoporosis.

Ampicillin concentrations in human oral tissues following a single oral administration of lenampicillin

1. Ampicillin concentrations in serum (n = 20), gingiva (n = 12), jawbone (n = 13), dental follicle (n = 12), radicular granuloma (n = 2) and radicular cyst (n = 2) were measured in specimens obtained during 0.5-2.5 hr after a single oral administration of lenampicillin (equivalent to 500 mg of ampicillin). 2. Measurable ampicillin concentrations were found in all serum and tissues. 3. Ampicillin concentrations in serum and tissues except for some gingiva and jawbone exceeded MIC for 90% of clinically isolated strains of alpha-hemolytic Streptococci. 4. Ampicillin concentrations in gingiva and jawbone were below the MIC for 90% in 2 out of 12 and 4 out of 13 specimens, respectively.