Passively sensing SARS-CoV-2 RNA in public transit buses

Affordably tracking the transmission of respiratory infectious diseases in urban transport infrastructures can inform individuals about potential exposure to diseases and guide public policymakers to prepare timely responses based on geographical transmission in different areas in the city. Towards that end, we designed and tested a method to detect SARS-CoV-2 RNA in the air filters of public buses, revealing that air filters could be used as passive fabric sensors for the detection of viral presence. We placed and retrieved filters in the existing HVAC systems of public buses to test for the presence of trapped SARS-CoV-2 RNA using phenol-chloroform extraction and RT-qPCR. SARS-CoV-2 RNA was detected in 14% (5/37) of public bus filters tested in Seattle, Washington, from August 2020 to March 2021. These results indicate that this sensing system is feasible and that, if scaled, this method could provide a unique lens into the geographically relevant transmission of SARS-CoV-2 through public transit rider vectors, pooling samples of riders over time in a passive manner without installing any additional systems on transit vehicles.

A comprehensive analysis of gene expression changes in a high replicate and open-source dataset of differentiating hiPSC-derived cardiomyocytes

We performed a comprehensive analysis of the transcriptional changes occurring during human induced pluripotent stem cell (hiPSC) differentiation to cardiomyocytes. Using single cell RNA-seq, we sequenced > 20,000 single cells from 55 independent samples representing two differentiation protocols and multiple hiPSC lines. Samples included experimental replicates ranging from undifferentiated hiPSCs to mixed populations of cells at D90 post-differentiation. Differentiated cell populations clustered by time point, with differential expression analysis revealing markers of cardiomyocyte differentiation and maturation changing from D12 to D90. We next performed a complementary cluster-independent sparse regression analysis to identify and rank genes that best assigned cells to differentiation time points. The two highest ranked genes between D12 and D24 (MYH7 and MYH6) resulted in an accuracy of 0.84, and the three highest ranked genes between D24 and D90 (A2M, H19, IGF2) resulted in an accuracy of 0.94, revealing that low dimensional gene features can identify differentiation or maturation stages in differentiating cardiomyocytes. Expression levels of select genes were validated using RNA FISH. Finally, we interrogated differences in cardiac gene expression resulting from two differentiation protocols, experimental replicates, and three hiPSC lines in the WTC-11 background to identify sources of variation across these experimental variables.

Spatial and cell type transcriptional landscape of human cerebellar development

The human neonatal cerebellum is one-fourth of its adult size yet contains the blueprint required to integrate environmental cues with developing motor, cognitive and emotional skills into adulthood. Although mature cerebellar neuroanatomy is well studied, understanding of its developmental origins is limited. In this study, we systematically mapped the molecular, cellular and spatial composition of human fetal cerebellum by combining laser capture microscopy and SPLiT-seq single-nucleus transcriptomics. We profiled functionally distinct regions and gene expression dynamics within cell types and across development. The resulting cell atlas demonstrates that the molecular organization of the cerebellar anlage recapitulates cytoarchitecturally distinct regions and developmentally transient cell types that are distinct from the mouse cerebellum. By mapping genes dominant for pediatric and adult neurological disorders onto our dataset, we identify relevant cell types underlying disease mechanisms. These data provide a resource for probing the cellular basis of human cerebellar development and disease.

Ovarian reserve may influence the outcome of bone mineral density in patients with long-term use of dienogest

Objective:

Long-term administration of dienogest, which is known to have effect on bone mineral density, is frequently done in patients with endometriosis and adenomyosis, but a few studies focused on the bone mineral density changes after finishing the long-term therapy. This study aimed to reveal the factors that adversely affect lumbar bone mineral density.

Method:

Fifty-seven premenopausal women who visited our hospital were diagnosed as either endometriosis or adenomyosis, and they were treated by dienogest for more than 115 weeks (26.5 months). Based on a previous report, bone mineral density changes less than 2% was categorized as the osteopenic group ( n = 30), and the others were assigned to the unchanged group ( n = 27). Bone mineral density was measured at the lumbar spine using dual-energy X-ray absorptiometry. A representative ovarian reserve marker, endogenous estradiol levels, and follicle-stimulating hormone levels were measured over time and were compared between the osteopenic and unchanged groups.

Result:

Duration of dienogest intake was 59.5 months (osteopenic group) versus 57.5 months (unchanged group). These patients experienced ovarian surgeries in a similar frequency, but the ovarian reserve in osteopenic group was impaired as suggested by the decline of endogenous estradiol level during intake of dienogest compared to that of unchanged group ( p = 0.0146). Endogenous follicle-stimulating hormone level between osteopenic group and unchanged group did not reach statistically significant difference, although the osteopenic group showed relatively higher level.

Conclusion:

This study might suggest that decreased ovarian reserve as judged by endogenous estradiol level is a factor that negatively affect bone mineral density, and measurement of endogenous estradiol level during intake of dienogest could have a predictive meaning of future decreased bone mineral density level.

Microbial single-cell RNA sequencing by split-pool barcoding

Single-cell RNA sequencing (scRNA-seq) has become an essential tool for characterizing gene expression in eukaryotes, but current methods are incompatible with bacteria. Here, we introduce microSPLiT (microbial split-pool ligation transcriptomics), a high-throughput scRNA-seq method for Gram-negative and Gram-positive bacteria that can resolve heterogeneous transcriptional states. We applied microSPLiT to >25,000 Bacillus subtilis cells sampled at different growth stages, creating an atlas of changes in metabolism and lifestyle. We retrieved detailed gene expression profiles associated with known, but rare, states such as competence and prophage induction and also identified unexpected gene expression states, including the heterogeneous activation of a niche metabolic pathway in a subpopulation of cells. MicroSPLiT paves the way to high-throughput analysis of gene expression in bacterial communities that are otherwise not amenable to single-cell analysis, such as natural microbiota.

Overcoming the ceiling effects of experts' motor expertise through active haptic training

One of the most challenging issues among experts is how to improve motor skills that have already been highly trained. Recent studies have proposed importance of both genetic predisposition and accumulated amount of practice for standing at the top of fields of sports and performing arts. In contrast to the two factors, what is unexplored is how one practices impacts on experts' expertise. Here, we show that training of active somatosensory function (active haptic training) enhances precise force control in the keystrokes and somatosensory functions specifically of expert pianists, but not of untrained individuals. By contrast, training that merely repeats the task with provision of error feedback, which is a typical training method, failed to improve the force control in the experts, but not in the untrained. These findings provide evidence that the limit of highly trained motor skills could be overcome by optimizing training methods.

Redefining the Etiologic Landscape of Cerebellar Malformations

Cerebellar malformations are diverse congenital anomalies frequently associated with developmental disability. Although genetic and prenatal non-genetic causes have been described, no systematic analysis has been performed. Here, we present a large-exome sequencing study of Dandy-Walker malformation (DWM) and cerebellar hypoplasia (CBLH). We performed exome sequencing in 282 individuals from 100 families with DWM or CBLH, and we established a molecular diagnosis in 36 of 100 families, with a significantly higher yield for CBLH (51%) than for DWM (16%). The 41 variants impact 27 neurodevelopmental-disorder-associated genes, thus demonstrating that CBLH and DWM are often features of monogenic neurodevelopmental disorders. Though only seven monogenic causes (19%) were identified in more than one individual, neuroimaging review of 131 additional individuals confirmed cerebellar abnormalities in 23 of 27 genetic disorders (85%). Prenatal risk factors were frequently found among individuals without a genetic diagnosis (30 of 64 individuals [47%]). Single-cell RNA sequencing of prenatal human cerebellar tissue revealed gene enrichment in neuronal and vascular cell types; this suggests that defective vasculogenesis may disrupt cerebellar development. Further, de novo gain-of-function variants in PDGFRB, a tyrosine kinase receptor essential for vascular progenitor signaling, were associated with CBLH, and this discovery links genetic and non-genetic etiologies. Our results suggest that genetic defects impact specific cerebellar cell types and implicate abnormal vascular development as a mechanism for cerebellar malformations. We also confirmed a major contribution for non-genetic prenatal factors in individuals with cerebellar abnormalities, substantially influencing diagnostic evaluation and counseling regarding recurrence risk and prognosis.

Cerebral Mitochondrial Microangiopathy Leads to Leukoencephalopathy in Mitochondrial Neurogastrointestinal Encephalopathy

BACKGROUND AND PURPOSE

Mitochondrial neurogastrointestinal encephalopathy is a rare disorder due to recessive mutations in the thymidine phosphorylase gene, encoding thymidine phosphorylase protein required for mitochondrial DNA replication. Clinical manifestations include gastrointestinal dysmotility and diffuse asymptomatic leukoencephalopathy. This study aimed to elucidate the mechanisms underlying brain leukoencephalopathy in patients with mitochondrial neurogastrointestinal encephalopathy by correlating multimodal neuroradiologic features to postmortem pathology.

MATERIALS AND METHODS

Seven patients underwent brain MR imaging, including single-voxel proton MR spectroscopy and diffusion imaging. Absolute concentrations of metabolites calculated by acquiring unsuppressed water spectra at multiple TEs, along with diffusion metrics based on the tensor model, were compared with those of healthy controls using unpaired t tests in multiple white matters regions. Brain postmortem histologic, immunohistochemical, and molecular analyses were performed in 1 patient.

RESULTS

All patients showed bilateral and nearly symmetric cerebral white matter hyperintensities on T2-weighted images, extending to the cerebellar white matter and brain stem in 4. White matter, N-acetylaspartate, creatine, and choline concentrations were significantly reduced compared with those in controls, with a prominent increase in the radial water diffusivity component. At postmortem examination, severe fibrosis of brain vessel smooth muscle was evident, along with mitochondrial DNA replication depletion in brain and vascular smooth-muscle and endothelial cells, without neuronal loss, myelin damage, or gliosis. Prominent periependymal cytochrome C oxidase deficiency was also observed.

CONCLUSIONS

Vascular functional and histologic alterations account for leukoencephalopathy in mitochondrial neurogastrointestinal encephalopathy. Thymidine toxicity and mitochondrial DNA replication depletion may induce microangiopathy and blood-brain-barrier dysfunction, leading to increased water content in the white matter. Periependymal cytochrome C oxidase deficiency could explain prominent periventricular impairment.

Examination of Visceral Perception and Gastric Tone by Gastric Stimulation Using Air Inflation during Endoscopy

This study investigated the assessment of visceral perception and gastric tone using insufflation during endoscopy. The intragastric pressure was measured during insufflation in 16 patients with gastro-oesophageal reflux disease, 25 patients with functional dyspepsia and 24 normal controls, using a pressure transducer inserted through the forceps aperture until gastric symptoms appeared. The intragastric pressure at the visceral perception threshold, the time to threshold and the time-pressure curve gradient were measured. The visceral perception threshold was significantly reduced in the functional dyspepsia group compared with the normal controls. Balloons were also inserted into the duodenal bulbs of 10 normal controls to investigate the effect of efflux of air into the duodenum; the measured parameters were not influenced by inflation and deflation. These results suggest that it is possible to assess visceral perception and gastric tone by measuring changes in intragastric pressure, using gastric stimulation by insufflation during endoscopy.

Liposome chaperon in cell-free membrane protein synthesis: one-step preparation of KcsA-integrated liposomes and electrophysiological analysis by the planar bilayer method

Chaperoning functions of liposomes were investigated using cell-free membrane protein synthesis.

Cytochemical studies of nuclear DNA and RNA in normal and abnormal keratinizing tissues

The distribution patterns of nuclear DNA and RNA in normal and abnormal keratinizing tissues of human skin were examined by electron microscopy, using an enzyme digestion technique. We found that the distribution of nucleic acids in the nuclei of epidermal cells during keratinization changes gradually. In the hair cells, particularly in the cells of hair cortex and Henle's layer of inner root sheath, essentially similar findings were observed. On the other hand, the distribution patterns observed in the tumor cells of calcifying epithelioma and the parakeratotic cells of psoriasis were different from each other and different from the distribution patterns of normal keratinizing tissue, hair, and epidermis. It seems that a similar pattern of reorganization of nucleic acids occurs in the nucleic of normal keratinizing cells as the cells keratinize. However, in abnormal tissue, it seems that the reorganization pattern of nucleic acids in the nuclei is different in each case.

Pharmacokinetics of everolimus when combined with cyclosporine in Japanese de novo renal transplant recipients

BACKGROUND

Currently, there are no published data on pharmacokinetics (PK) of everolimus in combination with cyclosporine in Japanese renal transplant patients. We evaluated the PK of everolimus in Japanese de novo renal transplant patients who received everolimus in combination with cyclosporine.

METHODS

In this phase 3, multicenter, randomized, open-label study, patients were randomized (1:1) to 1 of the 2 groups: everolimus 1.5 mg (targeted C0 of 3-8 ng/mL) plus reduced-dose cyclosporine or mycophenolate mofetil 2 g/d plus standard-dose cyclosporine. PK assessments for everolimus were performed on day 28 (month 1) in the PK subpopulation.

RESULTS

A total of 11 patients (7 men), mean age 47.5 ± 11.21 years, were enrolled for PK analysis of everolimus. Starting at 1.5 mg (0.75 mg twice a day), the mean dose over a period of 28 days was 0.705 ± 0.1011 mg. Everolimus mean trough concentration was 4.307 ± 1.2459 ng/mL and mean peak concentration was 13.539 ± 3.5330 ng/mL, which peaked at 1 to 2 hours postdose. The average concentration was 7.558 ± 1.4723 ng/mL, area under the concentration-time curve was 90.70 ± 17.667 ng·h/mL, and peak-trough fluctuation was 122.6%. The PK parameters of everolimus were comparable to those in the earlier phase 3 studies (A2306 and A2307). The mean everolimus trough levels were within the target ranges at all time points ranging from 3.4 to 5.5 ng/mL (everolimus 0.75 mg twice a day, safety population). The majority of patients (>85% from day 7 onward) were maintained within the targeted everolimus trough blood levels (safety population). These data were similar to a non-Japanese study (A2309).

CONCLUSIONS

The pharmacokinetic characteristics of everolimus in Japanese de novo renal transplant patients did not differ from those previously observed in non-Japanese patients, hence the same dosage of everolimus may be acceptable in Japanese patients.

1306-km 20x124.8-Gb/s PM-64QAM transmission over PSCF with net SEDP 11,300 (b ∙ km)/s/Hz using 1.15 samp/symb DAC

We demonstrated the transmission of a Nyquist-WDM signal based on PM-64QAM modulation in an EDFA-only submarine configuration composed of 54.4 km-long fiber spans: 20 channels at 124.8-Gb/s were propagated over 1306 km of low-loss pure-silica-core fiber (PSCF). Thanks to an aggressive digital spectral shaping, we achieved a raw spectral efficiency (SE) of 10.4 b/s/Hz, corresponding to 8.67 b/s/Hz net SE when considering a 20% FEC overhead. Transmitter DACs are operated at a record-low 1.15 samples/symbol, enabled by the insertion of advanced anti-alias filters. The achieved SE-times-distance product was 11,327 (b ∙ km)/(s ∙ Hz), the highest reported so far for PM-64QAM. Combining the experimental results with the performance predictions obtained using an analytical model of nonlinear propagation in uncompensated coherent optical systems (the so-called "GN-model"), we show that PM-64QAM is a realistic option for ultra-high capacity systems in the 1,000 km range, carrying up 40 Tb/s in the C-band.

In not only vertebroplasty but also kyphoplasty, the resolution of vertebral deformities depends on vertebral mobility

BACKGROUND AND PURPOSE

It has not been clarified whether the postoperative resolution of vertebral deformities achieved by KP are superior to those achieved by VP. We compared the outcomes of KP and VP, taking into account the presence of vertebral mobility, to determine whether the balloon inflation in KP may contribute to postoperative resolution of the vertebral deformities in patients with VCFs.

MATERIALS AND METHODS

The subjects had 34 vertebral bodies treated by VP, and 43 vertebral bodies treated by KP. In all patients, preoperative dynamic imaging was performed to assess the presence of vertebral mobility. First, the vertebral height restoration and kyphotic change were compared between the VP and KP groups. Then, the patients were further divided into 2 groups on the basis of the presence of vertebral mobility, and they were compared within and between the VP and KP groups in relation to the presence of vertebral mobility.

RESULTS

Overall, no significant differences were observed in either the vertebral height restoration or kyphotic change between the VP and KP groups (P > .20). Preoperative dynamic imaging identified 19 vertebral bodies each with vertebral mobility in the VP (56%) and KP groups (44%) (P = .21). Within the VP and KP groups, the vertebral height restoration and kyphotic changes were significantly better in patients with vertebral mobility than in those without (P < .01). There were no significant differences between the 2 treatment groups after adjustment for the presence of vertebral mobility (P > .30).

CONCLUSIONS

In both the VP and KP groups, the vertebral height restoration and kyphotic change largely depended on the preoperative vertebral mobility. The use of the balloon itself contributed little to resolution of the vertebral deformities.

Validity of intervertebral bone cement infusion for painful vertebral compression fractures based on the presence of vertebral mobility

BACKGROUND AND PURPOSE

It is uncertain whether analgesic effects of vertebroplasty in patients with painful VCF are actually attributable to intervertebral cement infusion. This study aims to assess the validity of cement infusion performed for pain relief based on the presence or absence of pseudoarthrosis.

MATERIALS AND METHODS

We compared therapeutic effects between PVP and vertebral perforation without bone cement infusion in patients with painful VCF. The subjects were 64 patients undergoing PVP (PVP group) and 67 undergoing vertebral perforation (perforation group). In all patients, preoperative dynamic radiography was performed to assess the presence of vertebral mobility. Patients were classified into 2 groups, those with and those without vertebral mobility, and changes in VAS and ADL scores before and after surgery were compared between the PVP and perforation groups.

RESULTS

Regarding patients with vertebral mobility, VAS improved during the 3 months immediately after surgery in the PVP group compared with the perforation group (P < .05). Although no significant difference in postoperative ADL scores was observed between the 2 treatment groups, the scores 3 months after surgery were better in the PVP group than in the perforation group. Meanwhile, in the subgroup of patients without vertebral mobility, both treatments produced marked pain relief, but the difference was not significant (P > .05). Moreover, there was no difference in ADL scores between the 2 treatment groups.

CONCLUSIONS

Intervertebral cement infusion exerts analgesic effects in patients with VCF with pseudoarthrosis. However, in those without vertebral mobility, the analgesic effects of vertebroplasty are the same regardless of bone cement infusion.

Tapering of the cervical spinal canal in patients with Chiari I malformations

BACKGROUND AND PURPOSE

Upper cervical spinal canal dimension may have a role in abnormal CSF dynamics in patients with Chiari I malformation. We attempted to measure spinal canal tapering from anteroposterior spinal canal dimensions in patients with Chiari I.

MATERIALS AND METHODS

Twenty-one patients with Chiari I malformation, including 12 with syringomyelia and 7 patients with IS were identified from a local registry. Age- and sex-matched control subjects with cervical spine MR imaging findings reported as normal were selected from the PACS. The anteroposterior diameter of the spinal canal was measured at C1-C7 on T2-weighted sagittal MR images. The taper ratio of the spinal canal was calculated with the regression line. Goodness of fit was calculated as R(2). Differences between patients with Chiari I and other patients were tested for significance with Kruskal-Wallis tests and multivariate analysis.

RESULTS

Taper ratios averaged -0.6 ± 0.3 mm/level in the patients with Chiari and syrinx, -0.4 ± 0.2 mm/level (mean ± 1 SD) in the patients with Chiari without syrinx, and -0.3 ± 0.5 mm/level in the patients with IS; control groups had average taper ratios of -0.3 ± 0.2 mm/level. Mean R(2) equaled 0.43. Taper ratios in patients with Chiari and syringomyelia differed significantly from those in the control group (P = .003). Taper ratios in the patients with Chiari without syrinx and in patients with IS did not differ significantly from their matched control groups (P = .60 and 0.76, respectively).

CONCLUSIONS

Patients with Chiari I and a syrinx have steeper tapering of the upper cervical spinal canal than matched controls.

Metamagnetic behavior and Kondo breakdown in heavy-fermion CeFePO

We report that nonmagnetic heavy-fermion (HF) iron oxypnictide CeFePO with two-dimensional XY-type anisotropy shows a metamagnetic behavior at the metamagnetic field H(M)≃4  T perpendicular to the c axis and that a critical behavior is observed around H(M). Although the magnetic character is entirely different from that in other Ce-based HF metamagnets, H(M) in these metamagnets is linearly proportional to the inverse of the effective mass, or to the temperature where the susceptibility shows a peak. This finding suggests that H(M) is a magnetic field breaking the local Kondo singlet, and the critical behavior around H(M) is driven by the Kondo breakdown accompanied by the Fermi-surface instability.

Comparative study of percutaneous vertebral body perforation and vertebroplasty for the treatment of painful vertebral compression fractures

BACKGROUND AND PURPOSE

Percutaneous vertebral body perforation is a new technique for treating painful VCFs. Herein, we compare the therapeutic effect of vertebral perforation and conventional vertebroplasty for treating VCFs.

MATERIALS AND METHODS

One hundred eight patients with single painful VCFs were assigned to undergo vertebral perforation (perforation group) or vertebroplasty (PVP group). Clinical outcomes were assessed by using the VAS. The associations of analgesic effect and clinical factors were also analyzed by multivariate regression. Plain radiographs were used to quantify the progression of vertebral body compression after surgery and to evaluate cement leakage and new vertebral fractures. The median follow-up time was 10 months.

RESULTS

Baseline characteristics were similar in the 2 groups. No factors correlated with analgesic effects in the PVP group. The analgesic effect of vertebral perforation was, however, related to the preoperative severity of vertebral compression and was low in patients with severe deformity (P < .05). Among patients with preoperative vertebral percentage of compression below 30%, there were no significant differences between the 2 groups in analgesic effect at any postoperative intervals. Progression of vertebral compression after surgery occurred in 22.2% and 16.0% of treated vertebrae in the perforation and PVP groups, respectively (P = .38). Respectively, 3.7% and 20.0% of the perforation and PVP groups had new postoperative fractures during follow-up (P < .05). There were no other complications.

CONCLUSIONS

Vertebral perforation was safe and effective for painful VCFs with slight compression. However, vertebroplasty should be considered for patients with marked vertebral body compression.

A comparison between SSMF and large-A(eff) Pure-Silica core fiber for ultra long-haul 100G transmission

We compare the transmission performance of 112-Gb/s POLMUX-QPSK modulation over large-A(eff) Pure-Silica core fiber and SSMF using EDFA-only amplification. The higher nonlinear threshold of the large-A(eff) Pure-Silica core fiber allows for a 55% increase in transmission distance. By using back-propagation an additional 10% increase is observed. In case spans with equal length for both fiber types and two splices per span only would have been used, resulting in a lower span loss for the large-A(eff) Pure-Silica core fiber, the total increase grows to 85%.

Natural history of MELAS associated with mitochondrial DNA m.3243A>G genotype

OBJECTIVE

To describe the natural history of clinical and laboratory features associated with the m.3243A>G mitochondrial DNA point mutation. Natural history data are needed to obtain prognostic information and for clinical trial planning.

METHODS

We included 85 matrilineal relatives from 35 families with at least 2 visits in this prospective cohort study. Thirty-one were fully symptomatic with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), and 54 were carrier relatives. Evaluations included standardized questionnaires (medical history and daily living functioning), physical examination, neuropsychological testing, and a battery of imaging and laboratory tests. We evaluated changes in clinical and laboratory features over time and survival. Outcomes are reported over a follow-up period of up to 10.6 years (mean 3.8 ± 2.2 years for patients and 5.5 ± 3.0 for carrier relatives).

RESULTS

Neurologic examination, neuropsychological testing, and daily living scores significantly declined in all patients with MELAS, whereas no significant deterioration occurred in carrier relatives. Cerebral MRI scores declined significantly in patients with MELAS. Magnetic resonance spectroscopy estimates of lactate in the lateral ventricles increased over time, and high lactate was associated with increased mortality. Symptom onset in childhood often was associated with worse outcome. Patients with MELAS had a greater death rate than carrier relatives.

CONCLUSIONS

Patients with MELAS carrying the m.3243A>G mutation show a measurable decline in clinical and imaging outcomes. It is hoped that these data will be helpful in anticipating the disease course and in planning clinical trials for MELAS.

Evaluation with three-dimensional computed tomography after anterior skull base reconstruction using two musculopericranial flaps and a grafted bone

Postoperative evaluation by three-dimensional (3D) computed tomography (CT) was performed in 15 patients who underwent anterior skull base reconstruction using two musculopericranial flaps and a grafted bone sandwiched between the two flaps. Especially in the case of large bone grafts (4 x 4 cm or more), the graft was positioned with the convex side facing upward into the cranial cavity to avoid creating an intracranial dead space. The extent of the absorption and changes in the contour of the grafted bone were evaluated. Imaging was done at a CT level of 150 using a Proceed 3-D CT scanner (Yokogawa Medical Co., Tokyo, Japan). Donor bone for grafting to the skull base was harvested the cranium in 10 patients and the ilium in 5 others. Patients ranged in age from 7 to 76 years (mean, 47); there were 10 men and 5 women. The grafted bone ranged in size from 1 x 2 cm to 5 x 8 cm (1 x 2 cm to about 4 x 3 cm: 10 patients; 4 x 4 to about 5 x 8 cm: 5 patients).No marked absorption of grafted bone was seen in these 15 patients, and no brain hernia occurred. In patients with large bone grafts (4 x 4 cm to about 5 x 8 cm), a graft that had been positioned with the convex side facing upward into cranial cavity at the time of transplant was subsequently observed to be transformed into a downward convex contour of normal skull base. Fostoperative infection did not occur because of the dead space nor were there any symptom of pressure on the brain because of the upward convexity of the grafted bone.The present reconstructive method is not only a minimum invasive but also a safe and reliable method for anterior skull base surgery.

Effects of the systemic administration of alendronate on bone formation in a porous hydroxyapatite/collagen composite and resorption by osteoclasts in a bone defect model in rabbits

Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 μm to 500 μm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 μg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks. In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites.