Psoas muscle area as a predictor of low muscle mass in Asian patients with compensated advanced chronic liver disease

PURPOSE

The relationship between the psoas muscle index (PMI) and the appendicular skeletal muscle index (ASMI) in patients with compensated advanced chronic liver disease (cACLD) is not yet understood. Our goal is to determine which level of the lumbar spine best represents the appendicular skeletal muscle.

METHODS AND MATERIALS

This retrospective study involved patients with cACLD between January 2020 and December 2021. We documented the patients' body weight, height, gait speed, handgrip strength, appendicular skeletal muscle measured by DXA, and psoas muscle area segmented on computed tomography or magnetic resonance imaging. Low muscle mass, as defined by the Asian working group for sarcopenia, is less than 7.0kg/m2 in males and less than 5.4kg/m2 in females. We analyzed the correlation between PMI and ASMI.

RESULTS

A total of 134 patients were enrolled in the study, with 74 being male and 60 being female. The mean age was 63.9±7.7 years old. Significant associations (p <0.001) were found between PMI of all levels and ASMI. In the analysis of Pearson's correlation coefficients, it was noted that the r value increased gradually in both males (r =0.3197 at L2, 0.4006 at L3, 0.5769 at L4) and females (r =0.3771 at L2, 0.4557 at L3, 0.5251 at L4). Similarly, the area under the curve (AUC) values predicting low muscle mass were as follows: for males, AUC=0.582 at L2, 0.619 at L3, 0.728 at L4; for females, AUC=0.685 at L2, 0.733 at L3, 0.744 at L4. The cut-off point for PMI in males was 4.12 at L2, 6.25 at L3, and 8.48 at L4, while in females was 2.61 at L2, 4.47 at L3, 6.07 at L4.

CONCLUSION

The Psoas muscle index can be used to assess the muscle mass status in patients with cACLD. Among the various levels that can be used, we recommend using the fourth inferior endplate of the lumbar spine, as it shows the highest correlation. Additionally, we suggest using a PMI cut-off point of 8.48 cm2/m2 for males and 6.07 cm2/m2 for females as a predictor of low muscle mass in Asian.

Posterior spinal fusion with lowest instrumented vertebra at L4 in idiopathic scoliosis: optimizing radiographic outcomes using pre-operative flexibility radiographs

PURPOSE

In idiopathic scoliosis (IS), there is general agreement ending PSFs at L3 or more cranial is preferred to optimize spinal motion, and extending PSFs to L4 may be necessary; however, this may also cause coronal imbalance or caudal disc wedging post-operatively due to leveling of L4 tilt. The purpose of this study was to identify a pre-operative radiographic measurement, which can be used to quantify the optimal amount of L4 tilt for ideal post-operative radiographic alignment.

METHODS

The study was a retrospective analysis of IS patients who underwent PSF to L4, with minimum 2-year follow-up post-operatively. Optimal outcome was defined by coronal balance, and L4-5 and L5-S1 disc wedging.

RESULTS

44 patients (84% females, mean age 13.6 years) were included. Analysis of pre-operative flexibility radiographs determined only the L5 tilt on the right side-bending (RSB) radiograph correlated with optimal outcome 2 (p = 0.03). To confirm the validity, the RSB value was subtracted from the post-operative C7-L4 tilt and the odds ratio analysis which was significantly correlated with optimal outcome 1 at final follow-up (OR 1.04, 95% CI 1-1.09).

CONCLUSIONS

In PSF to L4 for IS, L5 tilt measured from the pre-operative supine RSB radiograph can be used to optimize radiographic outcomes. Matching the pre-operative L5 tilt on RSB radiograph by leaving L4 tilted at the end of the PSF construct during surgery, quantified by the C7-L4 acute angle tilt, appears to be a useful method to achieve the desired post-operative alignment.

A 90-day rodent feeding study with grain for genetically modified maize L4 conferring insect resistance and glyphosate tolerance

A 90-day rat feeding study was performed to conduct a safety assessment on L4, a multi-gene genetically modified maize, conferring "Bt" insect resistance and glyphosate tolerance. A total of 140 Wistar rats were assigned to seven groups, 10 animals/group/sex, which comprised three genetically modified groups fed diets containing different concentrations of L4, three corresponding non-genetically modified groups fed diets containing different concentrations of zheng58 (parent plants), and a basal diet group fed the standard basal diet for 13 weeks. The fed diets contained L4 and Zheng58 at w/w% percentages of 12.5%, 25.0%, and 50% of the total. Animals were evaluated on some research parameters, including general behaviour, body weight/gain, feed consumption/efficiency, ophthalmology, clinical pathology, organ weights, and histopathology. Throughout the feeding trial, all animals were in good condition. No mortality and no biologically relevant effects or toxicologically significant alterations were observed in the total research parameters of the rats in the genetically modified groups compared with those in the basal diet group or their corresponding non-genetically modified groups. No adverse effects were observed in any of the animals. The results indicated that L4 is as safe and wholesome as conventional, non-genetically modified control maize.

L4 Corpectomy: Surgical Approaches and Mitigating the Risk of Femoral Nerve Injuries

OBJECTIVE

Because of the challenging anatomic location, corpectomies are performed less often at the fourth lumbar vertebral body than at other levels. Our objective was to review the literature of L4 corpectomy and anterior column reconstruction.

METHODS

A literature search in the Medline/PubMed database was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify all relevant cases and cases series describing corpectomies of the L4 vertebral body using "lumbar" AND "corpectomy" as search terms. We present an illustrative case to describe the technique.

RESULTS

We identified 18 articles with 30 patients who met the search criteria. Including our case illustration, the most common approach used was the lateral retroperitoneal approach (n = 17, 54.8%), of which 8 (26.7%) were performed via a transpsoas approach. Seven (23%) patients underwent corpectomy through a posterior approach, 4 (12.9%) through an anterior retroperitoneal approach, and 3 (10%) through combined anterior and lateral retroperitoneal. The overall complications rate was 19.3% including 1 case each of femoral nerve injury and iatrogenic lumbar nerve root injury.

CONCLUSIONS

Corpectomies of the L4 vertebral body are challenging. None of the various approaches described clearly demonstrates any superiority in mitigating the risk of neural complications. Decision making about which surgical approach to use should be based on patient-specific characteristics.

Body mass estimation from dimensions of the fourth lumbar vertebra in middle-aged Finns

Although body mass is not a stable trait over the lifespan, information regarding body size assists the forensic identification of unknown individuals. In this study, we aimed to study the potential of using the fourth lumbar vertebra (L4) for body mass estimation among contemporary Finns. Our sample comprised 1158 individuals from the Northern Finland Birth Cohort 1966 who had undergone measurements of body mass at age 31 and 46 and lumbar magnetic resonance imaging (MRI) at age 46. MRI scans were used to measure the maximum and minimum widths, depths, and heights of the L4 body. Their means and sum were calculated together with vertebral cross-sectional area (CSA) and volume. Ordinary least squares (OLS) and reduced major axis (RMA) regression was used to produce equations for body mass among the full sample (n = 1158) and among normal-weight individuals (n = 420). In our data, body mass was associated with all the L4 size parameters (R = 0.093-0.582, p ≤ 0.019 among the full sample; R = 0.243-0.696, p ≤ 0.002 among the normal-weight sample). RMA regression models seemed to fit the data better than OLS, with vertebral CSA having the highest predictive value in body mass estimation. In the full sample, the lowest standard errors were 6.1% (95% prediction interval ±9.6 kg) and 7.1% (±9.1 kg) among men and women, respectively. In the normal-weight sample, the lowest errors were 4.9% (±6.9 kg) and 4.7% (±5.7 kg) among men and women, respectively. Our results indicate that L4 dimensions are potentially useful in body mass estimation, especially in cases with only the axial skeleton available.

Methods to Determine the Role of Autophagy Proteins in C. elegans Aging

This chapter describes methods for the analysis of autophagy proteins in C. elegans aging. We discuss the strains to be considered, the methods for the delivery of double-stranded RNA, and the methods to measure autophagy levels, autophagic flux, and degradation by autophagy.

Clinching the cause: A review of foot drop secondary to lumbar degenerative diseases

Foot drop is defined as weakness on dorsiflexion of the foot. The top two most common etiologies for foot drop include lumbar degenerative disease and common peroneal nerve injury. This review provides "updates" on understanding the lumbar etiologies of foot drop. Since the publication of "Preoperative motor strength and time to surgery are the most important predictors of improvement in foot drop due to degenerative lumbar disease" in the Journal of Neurological Sciences, three cohort studies have been published on spinal causes of foot drop. Classification, clinical features, diagnosis, and pathogenesis that may 'clinch' the cause of foot drop are discussed in the context of these recent publications.

Estimation of stature from dimensions of the fourth lumbar vertebra in contemporary middle-aged Finns

BACKGROUND

Accurate stature estimation plays an essential role in the identification of unknown deceased individuals. For cases in which conventional methods of stature estimation are not applicable, we studied the stature estimation potential of the fourth lumbar vertebra (L4) among a large living sample of representative contemporary Finns. We also generated stature estimation equations for the middle-aged Finnish population.

MATERIAL AND METHODS

Our study population comprised the Northern Finland Birth Cohort 1966 for which lumbar magnetic resonance imaging (MRI) scans and objective measurements of stature were available from midlife (n=1358). After screening the MRI scans for vertebral pathologies, we measured the maximum and minimum widths, depths and heights of the L4 body with high precision and reliability. We then calculated their sums and means together with approximations of vertebral cross-sectional area and volume. By constructing simple and multiple linear regression models around the L4 parameters, we generated equations for stature prediction, and investigated their accuracy on the basis of the adjusted R squared (R²) and standard error of the estimate (SEE) values of the models.

RESULTS

The multiple linear regression models of the mean width, depth and height of L4 yielded the highest prediction accuracies with the lowest prediction errors (for the entire sample, R²=0.621 and SEE=5.635cm; for men, R²=0.306 and SEE=5.125cm; for women, R²=0.367 and SEE=4.640cm).

CONCLUSION

When conventional methods for estimating stature are not applicable, the lumbar vertebrae may be utilized for this purpose. Relatively accurate stature estimates can be given on the basis of only L4 dimensions.

Implication of C-type lectin receptor langerin and keratan sulfate disaccharide in emphysema

Glycosylation is profoundly involved in various diseases, and interactions between glycan binding proteins and their sugar ligands are plausible drug targets. Keratan sulfate (KS), a glycosaminoglycan, is downregulated in lungs by cigarette smoking, suggesting that KS is involved in smoking-related diseases, such as chronic obstructive pulmonary disease (COPD). We found that a highly sulfated KS disaccharide, L4, suppresses lung inflammation and is effective against COPD and its exacerbation in mouse models. Its anti-inflammatory activity was comparable to that of a steroid. As a possible mechanism, langerin, a C-type lectin receptor (CLR) expressed in dendritic cells, was suggested to function as an L4 receptor. Oligomeric L4 derivatives were chemically designed to create new ligands with higher affinity and activity. The synthetic L4 oligomers bound to langerin with over 1000-fold higher affinity than the L4 monomer, suggesting that these compounds are effective drug candidates against COPD and inflammatory diseases.

High affinity sugar ligands of C-type lectin receptor langerin

BACKGROUND

Langerin, a C-type lectin receptor (CLR) expressed in a subset of dendritic cells (DCs), binds to glycan ligands for pathogen capture and clearance. Previous studies revealed that langerin has an unusual binding affinity toward 6-sulfated galactose (Gal), a structure primarily found in keratan sulfate (KS). However, details and biological outcomes of this interaction have not been characterized. Based on a recent discovery that the disaccharide L4, a KS component that contains 6-sulfo-Gal, exhibits anti-inflammatory activity in mouse lung, we hypothesized that L4-related compounds are useful tools for characterizing the langerin-ligand interactions and their therapeutic application.

METHODS

We performed binding analysis between purified long and short forms of langerin and a series of KS disaccharide components. We also chemically synthesized oligomeric derivatives of L4 to develop a new high-affinity ligand of langerin.

RESULTS

We show that the binding critically requires the 6-sulfation of Gal and that the long form of langerin displays higher affinity than the short form. The synthesized trimeric (also designated as triangle or Tri) and polymeric (pendant) L4 derivatives displayed over 1000-fold higher affinity toward langerin than monomeric L4. The pendant L4, but not the L4 monomer, was found to effectively transduce langerin signaling in a model cell system.

CONCLUSIONS

L4 is a specific ligand for langerin. Oligomerization of L4 unit increased the affinity toward langerin.

GENERAL SIGNIFICANCE

These results suggest that oligomeric L4 derivatives will be useful for clarifying the langerin functions and for the development of new glycan-based anti-inflammatory drugs.

A keratan sulfate disaccharide prevents inflammation and the progression of emphysema in murine models

Emphysema is a typical component of chronic obstructive pulmonary disease (COPD), a progressive and inflammatory airway disease. However, no effective treatment currently exists. Here, we show that keratan sulfate (KS), one of the major glycosaminoglycans produced in the small airway, decreased in lungs of cigarette smoke-exposed mice. To confirm the protective effect of KS in the small airway, a disaccharide repeating unit of KS designated L4 ([SO₃^--6]Galβ1-4[SO₃^--6]GlcNAc) was administered to two murine models: elastase-induced-emphysema and LPS-induced exacerbation of a cigarette smoke-induced emphysema. Histological and microcomputed tomography analyses revealed that, in the mouse elastase-induced emphysema model, administration of L4 attenuated alveolar destruction. Treatment with L4 significantly reduced neutrophil influx, as well as the levels of inflammatory cytokines, tissue-degrading enzymes (matrix metalloproteinases), and myeloperoxidase in bronchoalveolar lavage fluid, suggesting that L4 suppressed inflammation in the lung. L4 consistently blocked the chemotactic migration of neutrophils in vitro. Moreover, in the case of the exacerbation model, L4 inhibited inflammatory cell accumulation to the same extent as that of dexamethasone. Taken together, L4 represents one of the potential glycan-based drugs for the treatment of COPD through its inhibitory action against inflammation.

Nicotine exposure caused significant transgenerational heritable behavioral changes in Caenorhabditis elegans

Passive and active exposure to tobacco smoking among youth is directly associated with immediate as well as long-term health deterioration. Despite all public health policies and efforts, the percentage of teenage smokers is still relatively high, especially in developing countries. Very few, if any, studies have been done on the transgenerational effect of nicotine exposed during the more sensitive, early developmental stages. We employed C. elegans as a biological model to study the multigenerational impact of chronic nicotine exposure. Nicotine treatment was limited to N2 hermaphrodites of the F0 generation. Exposure was limited to the larval period L1-L4 (~31 hours) after which worms were transferred to a fresh NGM plate. N2 hermaphrodites at L4 developmental stage were used for behavioral analysis across three generations: F0, F1, and F2. Our results show that nicotine was associated with changes in sinusoidal locomotion, speed, and body bends in L4 larvae in all three tested generations. These behavioral alterations were not restricted to F0, but were observed in F1 and F2 generations which were never exposed to nicotine. Our study is the first to reveal that nicotine addiction is heritable using C. elegans as a model organism. These results underscored the sensitivity of early development stages, with hope to spread more awareness to encourage the avoidance of nicotine exposure, especially at a young age.

Reduced competitiveness of Wolbachia infected Aedes aegypti larvae in intra- and inter-specific immature interactions

Wolbachia are maternally inherited intracellular bacteria that frequently infect a diverse range of arthropod species. Empirical and theoretical studies examining Wolbachia invasiveness have emphasized Wolbachia effects on adult hosts, but recent studies show that Wolbachia impacts on immature hosts can be important also. Here, we have examined for effects of Wolbachia infection in Aedes aegypti. Specifically, differential survivorship is observed when young larvae (1st instar) are exposed to older Aedes albopictus larvae (4th instar) or con-specific larvae. In an additional experiment, we have examined for differential behavior and observed that Wolbachia-infected larvae differ from uninfected larvae in their reaction to light stimulation. Our results support a hypothesized effect of Wolbachia on A. aegypti larval behavior. The results are discussed in relation to the ability of Wolbachia to invade natural populations and recently applied public health strategies that target the replacement or suppression of this important disease vector.

Early gamma oscillations

Gamma oscillations have long been considered to emerge late in development. However, recent studies have revealed that gamma oscillations are transiently expressed in the rat barrel cortex during the first postnatal week, a "critical" period of sensory-dependent barrel map formation. The mechanisms underlying the generation and physiological roles of early gamma oscillations (EGOs) in the development of thalamocortical circuits will be discussed in this review. In contrast to adult gamma oscillations, synchronized through gamma-rhythmic perisomatic inhibition, EGOs are primarily driven through feedforward gamma-rhythmic excitatory input from the thalamus. The recruitment of cortical interneurons to EGOs and the emergence of feedforward inhibition are observed by the end of the first postnatal week. EGOs facilitate the precise synchronization of topographically aligned thalamic and cortical neurons. The multiple replay of sensory input during EGOs supports long-term potentiation at thalamocortical synapses. We suggest that this early form of gamma oscillations, which is mechanistically different from adult gamma oscillations, guides barrel map formation during the critical developmental period.