Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non‐union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty‐four New‐Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:513–520, 2015.     

Retropharyngeal abscess--a ten-year experience

The authors present an extensive review of current literature as well as their ten-year experience in management of patients with retropharyngeal abscesses. Emphasis is placed upon age, sex, type and duration of symptoms, bacteriology, methods of diagnosis, therapy, and complications. The authors' series reveals that retropharyngeal abscesses are found in adults, there is a wide spectrum of bacteriological organisms represented, and with appropriate antibiotic and surgical management the majority of patients survive without major residual sequelae.     

Chronic otitis media requiring ventilation tubes in tracheotomized ventilator dependent children

The occurrence of sinusitis and middle ear effusions has frequently been attributed to the obstruction of the sinus ostia and/or eustachian tube. In the intensive care unit setting, edema caused by the irritation from nasogastric, nasotracheal and orotracheal tubes has been associated with this pathology and has been responsible for occult sepsis in this population. Our investigation was performed to determine the risk of chronic otitis media with effusion necessitating myringotomy with tympanostomy tubes among tracheotomized, ventilator dependent children in a consecutive series of children admitted to our recently created stable ventilator unit. We retrospectively reviewed the medical records of all tracheotomized, chronically ventilator dependent children < 48 months of age who had been hospitalized in this unit from the initial opening in September 1990 to January 1993. Data collected consisted of patient demographics, gestational age, cognitive abilities, age at onset of mechanical ventilation, age at tracheostomy, age at myringotomy, presence of nasogastric and gastroenterostomy tubes and evidence of gastric-esophageal reflux. All children underwent a tracheostomy procedure subsequent to the onset of mechanical ventilation. Of these patients, 9/12 (75%) later required myringotomy with tympanostomy tube placement following the occurrence of chronic otitis media with effusion. Ventilation tubes for chronic otitis media with effusion were not required in 3 patients. Using a case control study design, we examined the need of myringotomy tubes for children requiring continuous mechanical ventilation versus those requiring night-time only ventilation. The risk of myringotomy tubes in the continuously ventilated group (9/9) was significantly greater than the risk in the intermittently ventilated group (0/3) P < 0.01. We conclude chronic otitis media with effusion is a common finding among preschool-aged children who are tracheotomized and ventilator dependent. Routine periodic ENT evaluation may be indicated in all pediatric patients who require chronic mechanical ventilation. In this specific population of children, there may be a subset of patients who would benefit from prophylactic antibiotic therapy or tympanostomy tube insertion during the duration of positive pressure ventilation. Further prospective study is warranted.     

Dibenzylamine--a novel blocker of the voltage-dependent K+ current in myocardial mouse cells

Ventricular myocytes of the mouse ventricle were voltage clamped with a patch-clamp technique in the whole-cell configuration. At depolarizing voltage pulses, these myocytes develop a large voltage-dependent K+ outward current. Application of the drug dibenzylamine (DBA) to the bath solution blocked the voltage-dependent K+ current. The concentration/response relationship for the peak current at +40 mV indicates a 1:1 binding of the drug to the receptor with a concentration of half maximum effect of 43.1 micromol/l. The block did not require activation of the channels by depolarizing pulses. At concentrations causing partial block (25 micromol/l), the block was independent of voltage. At the same concentration, DBA completely blocked the slow component of the recovery from inactivation (-80 mV) whereas steady-state inactivation was not altered. It is concluded that DBA is a novel blocker of the voltage-dependent K+ current in mouse cardiac myocytes which preferentially affects the current component generating the slow recovery from inactivation.     

Number and timing of antenatal HIV testing: Evidence from a community-based study in Northern Vietnam

Background  

HIV testing for pregnant women is an important component for the success of prevention of mother-to-child transmission of HIV (PMTCT). A lack of antenatal HIV testing results in loss of benefits for HIV-infected mothers and their children. However, the provision of unnecessary repeat tests at a very late stage of pregnancy will reduce the beneficial effects of PMTCT and impose unnecessary costs for the individual woman as well as the health system. This study aims to assess the number and timing of antenatal HIV testing in a low-income setting where PMTCT programmes have been scaled up to reach first level health facilities.     

Colonic GLP‐2 is not Sufficient to Promote Jejunal Adaptation in a PN‐Dependent Rat Model of Human Short Bowel Syndrome

Background: Bowel resection may lead to short bowel syndrome (SBS), which often requires parenteral nutrition (PN) due to inadequate intestinal adaptation. The objective of this study was to determine the time course of adaptation and proglucagon system responses after bowel resection in a PN‐dependent rat model of SBS. Methods: Rats underwent jugular catheter placement and a 60% jejunoileal resection + cecectomy with jejunoileal anastomosis or transection control surgery. Rats were maintained exclusively with PN and killed at 4 hours to 12 days. A nonsurgical group served as baseline. Bowel growth and digestive capacity were assessed by mucosal mass, protein, DNA, histology, and sucrase activity. Plasma insulin‐like growth factor I (IGF‐I) and bioactive glucagon‐like peptide 2 (GLP‐2) were measured by radioimmunoassay. Results: Jejunum cellularity changed significantly over time with resection but not transection, peaking at days 3‐4 and declining by day 12. Jejunum sucrase‐specific activity decreased significantly with time after resection and transection. Colon crypt depth increased over time with resection but not transection, peaking at days 7‐12. Plasma bioactive GLP‐2 and colon proglucagon levels peaked from days 4‐7 after resection and then approached baseline. Plasma IGF‐I increased with resection through day 12. Jejunum and colon GLP‐2 receptor RNAs peaked by day 1 and then declined below baseline. Conclusions: After bowel resection resulting in SBS in the rat, peak proglucagon, plasma GLP‐2, and GLP‐2 receptor levels are insufficient to promote jejunal adaptation. The colon adapts with resection, expresses proglucagon, and should be preserved when possible in massive intestinal resection.