Purification and sequencing of neuropeptides contained in neuron R15 of Aplysia californica.

R15 is a large identified neuron present in the abdominal ganglion of the mollusc Aplysia. Previous studies have indicated that this neuron may play a role in water balance and possibly renovascular functions. A peptidic factor contained in the neuron R15 has been shown to increase the water content of Aplysia. To determine the structure of the peptides contained in R15, we purified the extracts of 820 R15 cells by means of two steps of reverse-phase HPLC. The purification yielded a number of peptides, only one of which, R15 alpha 1, resulted in water uptake when injected into animals. Determination of the amino acid content and sequence analysis of the R15 alpha 1 peptide demonstrated that this peptide contains 38 residues, including two cysteines. The peptide failed to react with iodoacetate, indicating that the two cysteines are connected by a disulfide bridge. To confirm the assigned structure, the peptide was synthesized with a disulfide bridge. The chromatographic properties and bioactivity of the synthetic material were identical to those of the native peptide. Several other R15 peptides were inactive in the bioassay for water uptake. The sequence of one of these peptides (R15 beta) was determined, and it was established that the peptide contains 28 residues. Amino acid analysis of three other peaks was performed. One of these peaks contained a peptide (R15 beta f) whose amino acid composition suggests that it is a fragment of the R15 beta peptide. The other two peaks contained peptides with identical amino acid compositions, suggesting that they are variants of a single peptide (R15 gamma). The amino acid sequences of all the peptides identified in neuron R15 correspond to stretches of a polyprotein encoded by a recently sequenced R15 cDNA.     

Anatomy of the lymphovenous valve of the thoracic duct in humans

The majority of lymph generated in the body is returned to the blood circulation via the lymphovenous junction (LVJ) of the thoracic duct (TD). A lymphovenous valve (LVV) is thought to guard this junction by regulating the flow of lymph to the veins and preventing blood from entering the lymphatic system. Despite these important functions, the morphology and mechanism of this valve remains unclear. The aim of this study was to investigate the anatomy of the LVV of the TD. To do this, the TD and the great veins of the left side of the neck were harvested from 16 human cadavers. The LVJs from 12 cadavers were successfully identified and examined macroscopically, microscopically, and using microcomputed tomography. In many specimens, the TD branched before entering the veins. Thus, from 12 cadavers, 21 LVJs were examined. Valves were present at 71% of LVJs (15/21) and were absent in the remainder. The LVV, when present, was typically a bicuspid semilunar valve, although the relative size and position of its cusps were variable. Microscopically, the valve cusps comprised luminal extensions of endothelium with a thin core of collagenous extracellular matrix. This study clearly demonstrated the morphology of the human LVV. This valve may prevent blood from entering the lymphatic system, but its variability and frequent absence calls into question its utility. Further structural and functional studies are required to better define the role of the LVV in health and disease.     

Degenerative lumbar spinal stenosis diagnostic value of the history and physical examination

Objective. To assess the value of the history and physical examination findings in the diagnosis of symptomatic degenerative lumbar spinal stenosis (LSS). Methods. The study was performed in 3 specialty clinics, and included patients with low back pain who were at least age 40. Findings from a standardized history and physical examination were compared with the diagnostic impression of expert attending clinicians. Imaging studies were available in 88% of those with LSS, and the findings further supported the diagnosis of LSS in each case. The sensitivity, specificity, and likelihood ratio associated with each history and physical examination finding were calculated in bivariate analyses, and independent correlates of LSS were identified with multivariate analyses. Results. Ninety-three patients were evaluated. History findings most strongly associated with the diagnosis of LSS (likelihood ratio ≥2) were greater age, severe lower-extremity pain, and absence of pain when seated. Physical examination findings most strongly associated with the diagnosis were wide-based gait, abnormal Romberg test result, thigh pain following 30 seconds of lumbar extension, and neuromuscular deficits. Independent correlates of LSS included advanced age (P = 0.0001), absence of pain when seated (P = 0.006), wide-based gait (P = 0.013), and thigh pain following 30 seconds of lumbar extension (P = 0.002). Conclusion. Specific history and physical examination findings are useful in the diagnosis of LSS and should be ascertained routinely in older patients with low back pain.     

The association between adverse childhood experiences and adult traumatic brain injury/concussion: a scoping review

Background: Adverse childhood experiences are significant risk factors for physical and mental illnesses in adulthood. Traumatic brain injury/concussion is a challenging condition where pre-injury factors may affect recovery. The association between childhood adversity and traumatic brain injury/concussion has not been previously reviewed. The research question addressed is: What is known from the existing literature about the association between adverse childhood experiences and traumatic brain injury/concussion in adults?

Methods: All original studies of any type published in English since 2007 on adverse childhood experiences and traumatic brain injury/concussion outcomes were included. The literature search was conducted in multiple electronic databases. Arksey and O’Malley and Levac et al.’s scoping review frameworks were used. Two reviewers independently completed screening and data abstraction.

Results: The review yielded six observational studies. Included studies were limited to incarcerated or homeless samples, and individuals at high-risk of or with mental illnesses. Across studies, methods for childhood adversity and traumatic brain injury/concussion assessment were heterogeneous.

Discussion: A positive association between adverse childhood experiences and traumatic brain injury occurrence was identified. The review highlights the importance of screening and treatment of adverse childhood experiences. Future research should extend to the general population and implications on injury recovery.

• Implications for rehabilitation

• Exposure to adverse childhood experiences is associated with increased risk of traumatic brain injury.

• Specific types of adverse childhood experiences associated with risk of traumatic brain injury include childhood physical abuse, psychological abuse, household member incarceration, and household member drug abuse.

• Clinicians and researchers should inquire about adverse childhood experiences in all people with traumatic brain injury as pre-injury health conditions can affect recovery.

     

Superiority of Higher-Volume Fresh Feces Compared to Lower-Volume Frozen Feces in Fecal Microbiota Transplantation for Recurrent Clostridioides Difficile Colitis

Digestive Diseases and Sciences - To compare the clinical outcomes of different protocols for fecal microbiota transplantation (FMT) in two community hospitals with similar patient demographics....