Modified retro-tubercle opening-wedge versus conventional high tibial osteotomy

Despite the fact that common surgical techniques for the treatment of genu varum usually correct the malalignment in the affected knee, these methods have significant complications and cause problems in the long term. Retro-tubercle opening-wedge high tibial osteotomy is among the newer techniques for the treatment of genu varum. The goal of this study was to compare the results of retro-tubercle opening-wedge high tibial osteotomy with those of medial opening-wedge osteotomy. In a randomized, controlled trial, 72 patients with varus knees who were scheduled for surgery were assigned into either the retro-tubercle opening-wedge high tibial osteotomy (n=34) or medial opening-wedge osteotomy groups (n=38). Groups were matched for age and sex. The position of the patella was compared with respect to the tuberosity and the upper tibial slope pre- and postoperatively. Patients were followed for an average of 13 months (range, 10-21 months). In the retro-tubercle opening-wedge high tibial osteotomy group, the length of the patellar tendon did not significantly differ pre- and postoperatively (P≥.5); however, in the medial opening-wedge osteotomy group, a statistically significant shortening was noted in patellar tendon postoperatively (P≤.05). Similarly, the tibial plateau inclination showed a statistically significant difference postoperatively in the medial opening-wedge osteotomy group, while the difference in the retro-tubercle opening-wedge high tibial osteotomy group did not reach statistical significance.     

Study of CO⋯HN Hydrogen bond interactions in amyloid beta (Aβ): A DFT study of the electric field gradient and CS tensors and NBO analysis

A systematic computational density functional theory (DFT) study was carried out in amyloid-beta (Aβ) structure to investigate the hydrogen bonding interactions (HBs) effects on Chemical shielding (CS) and electric field gradient (EFG) tensors in site of hydrogen, oxygen, nitrogen and carbon nuclei. The results indicate that these tensors are more sensitive to the HB interactions in dimer model than those of trimer model. The calculated 15N and 13C in CS tensors in trimer model are in good agreement with experimental data. Natural bonding orbital analysis, NBO, indicate a reasonable correlation between 14N quadrupole coupling constant (C_Q) and strength of Fock matrix elements (F_ij). Moreover, the quantum chemical calculations indicated that the intermolecular the HB interactions play an essential role in variation of the relative orientation of CS and EFG tensors of nitrogen, hydrogen and oxygen nuclei in the molecular frame axes. Finally, 17O C_Q and η_Q show great dependency to backbone conformation, specifically dihedral angles ψ (psi).     

The natural history of anterior knee pain in 2 posterior-stabilized, modular total knee arthroplasty designs

Anterior knee pain (AKP) has been a persistent complaint after total knee arthroplasty; however, the natural course of this complaint has not been fully investigated. This is a 10-year follow-up report of a prospective, randomized study between the Insall-Burstein II (Zimmer, Warsaw, IN) and the Press Fit Condylar Modular (Johnson & Johnson, Raynham, MA) knees. Up to one third of total knee arthroplasties will experience mild to moderate AKP at 1-year follow-up, which will persist in approximately 30% of these previously symptomatic knees at 10-year follow-up. New-onset AKP will develop in approximately 10% of previously asymptomatic knees.     

Iniencephaly: clinical, radiological and surgical findings

The authors report a case of iniencephaly in a 6-year-old boy with a huge occipital bone defect and encephalocele, extensive spina bifida of the cervical vertebrae and fixed retroflexion of the head due to Sprengel's deformity. He presented with some cerebellar and cranial nerve symptoms and new episodes of neck pain and drop attacks. Brain imaging confirmed progressive deformity of the brain stem, cerebellar herniation into the encephalocele sac and ventriculomegaly. Surgical repair of the encephalocele was performed with preservation of all herniated cerebellar tissue and the release of thick arachnoid adhesions to make more space to return the herniated neural tissue from the sac to the cranium. The patient was found to have progressive facial palsy and intracranial hypertension 3 days after surgery, which improved with ventriculoperitoneal shunting. Iniencephaly is generally a fatal anomaly, and only 7 such patients have been reported to have survived. Because of the fatality of this anomaly, prenatal diagnosis of iniencephly and pregnancy termination are important. The patient presented herein is only the second patient with iniencephaly and encephalocele to be operated on. The severity of associated systemic and cranial abnormalities is fundamental with regard to survival. Essential points for surgery are preparing enough space to save herniated functional neural tissues, management of associated hydrocephalus and brain stem rotation/compression due to decreased postoperative space. In the surviving child, early correction of Sprengel's deformity would provide a better aesthetic position of the neck with preservation of brachial plexus integrity.     

Treadmill training enhances rat agouti-related protein in plasma and reduces ghrelin levels in plasma and soleus muscle

Ghrelin and agouti-related protein (AgRP) are orexigenic peptides secreted from stomach mucosa and the arcuate nucleus of the hypothalamus, respectively. Both peptides affect feeding behavior and play a role in energy balance, glucose homeostasis, and adiposity. The purpose of the current study was to determine the effects of moderate-term (6 weeks) running regimen on resting levels of ghrelin, AgRP, adenosine triphosphate, and glycogen in soleus muscle as well as plasma concentrations of the orexigenic hormones. Eighteen adult Wistar male rats (12 weeks old, 235-255 g) were randomly assigned to training (n = 10) and control (n = 8) groups. The training group ran for 60 min/d, 5d/wk at 25 m/min and 0% grade for 6 weeks. Forty-eight hours after the last exercise session, rats were killed; and soleus muscle and plasma were collected and frozen in liquid nitrogen for later analysis. Results demonstrated that 6 weeks of treadmill exercise reduced ghrelin and increased AgRP levels in plasma. Trained rat soleus muscle had higher levels of glycogen but not adenosine triphosphate or AgRP compared with untrained controls. Data indicate that training lowers ghrelin levels in rat soleus and plasma, which is accompanied by higher plasma AgRP and soleus glycogen content.     

Hypoglycemia leads to age-related loss of vision

The retina is among the most metabolically active tissues in the body, requiring a constant supply of blood glucose to sustain function. We assessed the impact of low blood glucose on the vision of C57BL/6J mice rendered hypoglycemic by a null mutation of the glucagon receptor gene, Gcgr. Metabolic stress from moderate hypoglycemia led to late-onset loss of retinal function in Gcgr(-/-) mice, loss of visual acuity, and eventual death of retinal cells. Retinal function measured by the electroretinogram b-wave threshold declined >100-fold from age 9 to 13 months, whereas decreases in photoreceptor function measured by the ERG a-wave were delayed by 3 months. At 10 months of age Gcgr(-/-) mice began to lose visual acuity and exhibit changes in retinal anatomy, including an increase in cell death that was initially more pronounced in the inner retina. Decreases in retinal function and visual acuity correlated directly with the degree of hypoglycemia. This work demonstrates a metabolic-stress-induced loss of vision in mammals, which has not been described previously. Linkage between low blood glucose and loss of vision in mice may highlight the importance for glycemic control in diabetics and retinal diseases related to metabolic stress as macular degeneration.