Biochemical aspects of symbiosis in carbon and nitrogen metabolism in higher termites

A comprehensive study of carbon metabolism has been carried out on representatives of two genera of higher termites, Nasutitermes walkeri and the fungus gardeners, Macrotermes spp. Substantial activity of cellulase and its components endo-B-l,4—glucanase and B—glucosidase, was found in workers of N. walkeri, Macrotermes michaelseni M. subhyalinus, M. bellicosus and M. mulleri. Less activity was found in the soldiers and none in the larvae of the Macrotermes spp. In fungal material associated with Macrotermes spp. only the fungal nodules had significant enzyme activity. In N. walkeri and M. michaelseni at least 90% of all enzyme activities was found in the midgut, with the exception of endo-B-l,4-xy1anase activity which was not measured in M. michaelseni. Low levels of endo-fi-l,4—xylanase activity were evenly distributed throughout the gut of N. walkeri. Midgut enzyme activity was restricted to the anterior region. The salivary glands contained variable amounts of enzyme activities. Less than 5% of the endo-B-l,4— glucanase activity was located in the hindgut. The endogenous cellulase from N. walkeri consisted of multiple B-glucosidase and endo-B-1,4- glucanase components. Elution profiles of fungal endo-B—l,4—glucanase activities on Bio-Gel® P-150 indicate that each Macrotermes spp. has a different Termitomyces sp. associated with it, consisting of one to three endo-B-l,4-glucanase activities. Endo-B-1,4-glucanase components from termite workers also consisted of one to three enzymes. A comparison of the elution profiles on Bio-Gel® P-60 of endo-B-lA—glucanase and Bglucosidase activities from fungal and termite material was used to show the absence of fungal enzymes in the termite gut. Similar results were found with fungal and termite material from M. bellicosus and M. mulleri using Bio-Gel® P—150 chromatography

Cervical lymph node metastasis in adenoid cystic carcinoma of the larynx: a collective international review

Adenoid cystic carcinoma (AdCC) of the head and neck is a well-recognized pathologic entity that rarely occurs in the larynx. Although the 5-year locoregional control rates are high, distant metastasis has a tendency to appear more than 5 years post treatment. Because AdCC of the larynx is uncommon, it is difficult to standardize a treatment protocol. One of the controversial points is the decision whether or not to perform an elective neck dissection on these patients. Because there is contradictory information about this issue, we have critically reviewed the literature from 1912 to 2015 on all reported cases of AdCC of the larynx in order to clarify this issue. During the most recent period of our review (1991-2015) with a more exact diagnosis of the tumor histology, 142 cases were observed of AdCC of the larynx, of which 91 patients had data pertaining to lymph node status. Eleven of the 91 patients (12.1%) had nodal metastasis and, based on this low proportion of patients, routine elective neck dissection is therefore not recommended

Comparative Treatment Outcomes for Patients With Idiopathic Subglottic Stenosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadImportance: Surgical treatment comparisons in rare diseases are difficult secondary to the geographic distribution of patients. Fortunately, emerging technologies offer promise to reduce these barriers for research. Objective: To prospectively compare the outcomes of the 3 most common surgical approaches for idiopathic subglottic stenosis (iSGS), a rare airway disease. Design, setting, and participants: In this international, prospective, 3-year multicenter cohort study, 810 patients with untreated, newly diagnosed, or previously treated iSGS were enrolled after undergoing a surgical procedure (endoscopic dilation [ED], endoscopic resection with adjuvant medical therapy [ERMT], or cricotracheal resection [CTR]). Patients were recruited from clinician practices in the North American Airway Collaborative and an online iSGS community on Facebook. Main outcomes and measures: The primary end point was days from initial surgical procedure to recurrent surgical procedure. Secondary end points included quality of life using the Clinical COPD (chronic obstructive pulmonary disease) Questionnaire (CCQ), Voice Handicap Index-10 (VHI-10), Eating Assessment Test-10 (EAT-10), the 12-Item Short-Form Version 2 (SF-12v2), and postoperative complications. Results: Of 810 patients in this cohort, 798 (98.5%) were female and 787 (97.2%) were white, with a median age of 50 years (interquartile range, 43-58 years). Index surgical procedures were ED (n = 603; 74.4%), ERMT (n = 121; 14.9%), and CTR (n = 86; 10.6%). Overall, 185 patients (22.8%) had a recurrent surgical procedure during the 3-year study, but recurrence differed by modality (CTR, 1 patient [1.2%]; ERMT, 15 [12.4%]; and ED, 169 [28.0%]). Weighted, propensity score-matched, Cox proportional hazards regression models showed ED was inferior to ERMT (hazard ratio [HR], 3.16; 95% CI, 1.8-5.5). Among successfully treated patients without recurrence, those treated with CTR had the best CCQ (0.75 points) and SF-12v2 (54 points) scores and worst VHI-10 score (13 points) 360 days after enrollment as well as the greatest perioperative risk. Conclusions and relevance: In this cohort study of 810 patients with iSGS, endoscopic dilation, the most popular surgical approach for iSGS, was associated with a higher recurrence rate compared with other procedures. Cricotracheal resection offered the most durable results but showed the greatest perioperative risk and the worst long-term voice outcomes. Endoscopic resection with medical therapy was associated with better disease control compared with ED and had minimal association with vocal function. These results may be used to inform individual patient treatment decision-making.Patient-Centered Outcomes Research Institute - PCOR

Fault Analysis of Vision System on Autonomous Blast Hole Drills

Rio Tinto has a continually increasing number of autonomous blast hole drills operating on multiple sites in the Pilbara region of Western Australia. The vision system on these drills forms a critical layer of the functional safety system in which they operate. This research project is to objectively analyse fault data in order to ascertain best practice solutions to reduce lost time for repairs and maintenance to the components of this system. An autonomous blast hole drill operates on a blast pattern in an active mining environment. These drills need to be able to interact safely with other production machines, support vehicles and personnel on foot at all times. The vision system is used by a remote operator in Perth in conjunction with an object detection system to safely operate. By analysing historical fault data and interviewing support personnel, common fault modes and patterns can be identified. In depth analysis will be performed on each type of failure, the probable causes, repair options and failings in the current processes. Targeting these common fault modes reveals two areas of improvement and their respective solutions. Low complexity hardware faults of gears or motors and software configuration faults on the PTZ cameras. By delivering a hand-held configuration tool to resolve the configuration problems for any user hardware and software issues. The PTZ camera configuration tool dramatically reduces the repair time simply by reducing the complexity of the task. Also, by taking ownership and responsibility of low complexity repairs, the time and cost savings can be significant, especially in remote mining environments

The Indoor Environment and Otitis Media among Australian Children: A National Cross-Sectional Study

The association between the indoor environment and lifetime prevalence of otitis media (OM) in Australian children was assessed. We analysed data from a cross-sectional study of children, aged 7–11 years, performed in twelve Australian cities during 2007–2008. The main outcome was a parental report of their child’s diagnosis with OM by a doctor. Information on the indoor environment (energy sources used for heating, cooling, and cooking, pets, and second-hand smoke exposure), in the first year of life and at present, was collected from parents by a questionnaire. Multi-level logistic regression models were used to adjust for individual- and area-level confounders. Our analysis comprised 2872 children (51% female, mean age: 10.0 (SD 1.2)). Of those, 1097 (39%) were reported to have OM. Exposure to gas heating in the first year of life was significantly associated with higher odds of OM in adjusted models (OR:1.22; 95% CI: 1.00,1.47), as was current exposure to reverse-cycle air conditioning (OR: 1.52, 95% CI: 1.27,1.82). Ownership of a cat or dog at any time was also associated with high odds of OM (OR: 1.50; 95% CI: 1.17,1.92). No other significant associations were observed. In this national study of Australian children, indoor environmental exposures associated with the lifetime prevalence of OM were gas heating, reverse-cycle air conditioning and pet ownership. Exposures in both early life and later childhood may both play a role in OM

The microbiology and biochemistry of the Australian termite, Mastotermes darwiniensis

The microbiological and biochemical aspects of digestion in the lower termite Mastotermes darwiniensis were investigated with particular emphasis on the role of the symbiotic microbiota. The digestive tract of !:h darwiniensis is typical of the Isoptera with paired salivary glands emptying into a foregut and the midgut separated from the hindgut by twelve Malpighian tubules. The hindgut contains the symbiotic microbiota - four species of large protozoa, three species of small protozoa and a variety of bacteria. The cuticle of the hindgut is marked with depressions and pores, and a number of morphotypes of attached bacteria. The major bacteria iso­lated from the hindgut, Streptococcus and Enterobacter, are not con­sistent with the main types attached to the cuticle observed by electron microscopy, suggesting the isolated bacteria represent those free in the lumen. No cellulolytic bacteria were isolated. The gut is surrounded by fat body tissue which was examined using light and electron microscopy. Three cell types were present: trophocytes or fat cells, urocytes which contain urate deposits, an mycetocytes. Endosymbiotic bacteria, long curved Gram-positive rods, were enclosed in vacuoles in the mycetocyte cytoplasm. Morphometric analysis of electron micrographs indicated that the bacteria and associated vacuoles accounted for 61% of the mycetocyte volume. Attempts to cu 1 ture these bacteria using a wide range of media and conditions were unsuccessful, indicating a very specialised rela­tionship of the bacterium with its environment. To determine the physico-chemical properties of the various gut sec­tions, termites were fed redox and pH indicators. The foregut and midgut were aerobic with an Eh greater than + 100 mV, whereas thepaunch and co 1 on were anaerobic with an Eh of -200 · mV. The rectum had an Eh of + 5mV. The pH rises from a strongly acidic foregut to neutral to alkaline midgut, declining to a slightly acidic paunch and colon, and finally a strongly acidic rectum. Removal of the protozoa and spirochaetes by high pressure oxygen treatment and complete remo­val of the microbiota by feeding tetracycline showed the bacteria were responsible for maintaining the redox potential of the hindgut suitable for the anaerobic components of the microbiota. The distribution of a number of important digestive enzymes was also studied. Under normal conditions, most of the cellulase activity (40 to 75%) was found in the hi ndgut where the symbi ants are 1 ocated. Small amounts of activity were found in the salivary glands and midgut. The cellulases from the hindgut and salivary glands differed in pH profile and product formation. The salivary glands were the major source of a-amylase while the midgut was the major source of cellobiase, maltase, invertase and protease. When termites were starved, cellulase activity declined in all gut sections, disappearing completely in the hindgut. This was asso­ciated with the death of the large protozoa and the decline in num- bers of small protozoa. When termites were fed starch, the cellulase levels again declined and the large protozoa died; however, the small protozoa remained unaffected. Amylase levels remained normal and the termites survived indefinitely. Apparently, amylase levels were sufficient to produce enough energy for the termite and its remaining symbionts. If termites were transferred to a wood diet after being fed starch, the termites died. If, however, they were refaunated with the large protozoa, they were again able to live on wood. Thus on a normal cellulose diet the termites have an absolute requirement for the large protozoa which in turn have a specific requirement for cellulose and are responsible for the production of cellulase in the hindgut. Acetate, a product of cellulose fermentation, was found predominantly in the hindgut. Acetate levels declined by 50% following the death of the large protozoa during the feeding experiments, indicating that only about half of the acetate present in the hindgut of nonnal termites is produced by cellulose fermentation by the large protozoa. Experiments with 14c-acetate showed that acetate was able to pass through the gut wall, illustrating that the termite can derive metabolites from its gut symbionts