Tracheal slowly adapting stretch receptors: Theoretical models

Explanations and conditions given for the occurrence of diffusive structure in two-species ecosystem models do not generalize to systems with three or more species.     

Purification,properties, and mode of action of hemicellulase I produced by Ceratocystis paradoxa

A culture isolate (CP₂) of the fungal plant pathogen Ceratocystis paradoxa produces at least five extra-cellular hemicellulases when grown on a medium containing a commercial hemicellulose as inducer. One of the five enzymes, hemicellulase I (HC-I), was purified by ammonium sulphate precipitation, ion-exchange chromatography (DEAE-Sephadex and then Cellex-CM), and iso-electric focusing at pH 3–10 and 8–10. HC-I behaves as a single protein on electrophoresis at pH 6.0 and 8.4. The enzyme degrades hemicellulose B (an arabino-4-O-methylglucuronoxylan) and arabinoxylan to arabinose, xylose, xylobiose (Xyl₂; β-D-Xylp-(1→4)-D-Xyl), and a mixture of arabinose-xylose and xylose oligosaccharides (AraXyl_n and Xyl_n, where n  3, 4, or 5). The enzyme is deduced to be an endo-enzyme. Xylotetraose (Xyl₄) was the lowest homologue of the xylose oligosaccharides attacked, yielding xylobiose and xylotriose (Xyl₃) only. A mechanism is postulated for this reaction. AraXyl₂AraXyl₅ were slowly hydrolysed to arabinose and the respective xylose saccharide (Xyl₂Xyl₅), and thence to Xyl₂ and Xyl₃. Hydrolysis of the arabinofuranosyl linkage probably does not occur at the same active site as for the xylose oligosaccharides. Hemicellulose B fractions from different sources appeared to be degraded by HC-I. The enzyme showed optimum activity at pH 5.5 and 40°, and K_m was 4.24 mg of hemicellulose/ml.     

Studies on the swimming musculature of the rainbow trout I. Fibre types

A histochemical study has been made on the myotomal musculature of the rainbow trout Salmo gairdneri Richardson. Four main types of fibre can be distinguished on the basis of differences in fibre size, lipid content and succinic dehydrogenase and myofibrillar adenosine triphosphatase activity (ATPase activity). Early histological studies have concluded that in addition to a superficial strip of muscle small diameter 'red' fibres occur throughout the trout myotome. These small diameter fibres occurring in the bulk of the myotome are shown to differ from the superficial fibres with respect to their oxidative metabolism and myofibrillar ATPase. The relevance of this finding to studies on the energetics and swimming efficiency of this species are discussed.     

A cutin acid in Pinus sylvestris microspores

Nonacosan-10-ol (0.7%) and the cutin acid, 9,16-dihydroxyhexadecanoic acid (0.3%) are present in Pinus sylvestris microspores. The pollen coat hence has some features in common with leaf cuticles.     

Genetic control of susceptibility of mice to Rous sarcoma virus tumorigenesis

Studies with congenic resistant strains of mice indicate that susceptibility to Rous sarcoma virus tumorigenesis is influenced by a gene or genes associated with the major histocompatibility complex (H-2). These genes manifest dominant relative susceptibility. Preliminary studies indicate that the CBA/J strain harbors a gene or genes for relative susceptibility, which are recessive. These results are compared with other studies onH-2-associated genes affecting murine viral oncogenesis.     

Intrathecal Morphine Use in Adolescent Idiopathic Scoliosis Surgery is Associated with Decreased Opioid Use and Decreased Length of Stay

BackgroundLength of stay (LOS) in the hospital following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has decreased over the past decade due to well-defined postoperative clinical pathways, earlier mobilization, and improved pain control methods. Historically, liberal use of parenteral and oral opioids for pain control caused side effects, resulting in delayed discharge. Intraoperative intrathecal morphine (ITM) has been posited to reduce the need for postoperative opioids and to expedite the discharge process. This study examines the relationship between the use of ITM with average required postoperative opioid usage and with average LOS.MethodsThis IRB-approved retrospective cohort study examined 105 patients with AIS who received PSF with instrumentation split into two cohorts. One cohort underwent PSF via standard surgical protocol (n=40) while the other cohort received intraoperative ITM with the standard surgical protocol (n=65). Power analysis demonstrated a study power of 0.8. LOS and total postoperative opioid analgesic medication (morphine milligram equivalent, MME) data were collected. Age at surgery, gender, number of spinal levels fused, estimated intraoperative blood loss (EBL), preoperative Cobb angle, and any complications related to the use of ITM were also recorded. Continuous variables were analyzed with Student’s t-test and categorical variables were analyzed with chi-square independent-sample tests using SAS 9.4 (α = 0.05).ResultsPatients who were treated with ITM displayed shorter LOS (p<0.0001) and reduced postoperative analgesic requirement (p<0.0001). Patients who received ITM spent an average of 1.8 fewer midnights in the hospital and received an average of 221.2 MME less than patients who received standard protocol (57% decrease). There were no significant differences between the two groups for any other variable.ConclusionIntraoperative ITM is a simple and effective treatment for scoliosis surgeons to better control postoperative pain in patients, reduce the risk of dependency, and achieve earlier discharge from the hospital. Shortened LOS reduces the overall cost of care, benefitting patients, hospitals, and insurance companies. Based on the results of this study and several earlier studies, the authors recommended that scoliosis surgeons consider incorporating use of ITM into their standard operative protocols. Level of Evidence: IV     

Bile acid receptors as targets for the treatment of dyslipidemia and cardiovascular disease

Dyslipidemia is an important risk factor for cardiovascular disease (CVD) and atherosclerosis. When dyslipidemia coincides with other metabolic disorders such as obesity, hypertension, and glucose intolerance, defined as the metabolic syndrome (MS), individuals present an elevated risk to develop type 2 diabetes (T2D) as well as CVD. Because the MS epidemic represents a growing public health problem worldwide, the development of therapies remains a major challenge. Alterations of bile acid pool regulation in T2D have revealed a link between bile acid and metabolic homeostasis. The bile acid receptors farnesoid X receptor (FXR) and TGR5 both regulate lipid, glucose, and energy metabolism, rendering them potential pharmacological targets for MS therapy. This review discusses the mechanisms of metabolic regulation by FXR and TGR5 and the utility relevance of natural and synthetic modulators of FXR and TGR5 activity, including bile acid sequestrants, in the treatment of the MS.