Primary sequence, copy number, and distribution of mariner transposons in the honey bee

A single honey bee mariner transposon (TnM1a) was sequenced, revealing a transpositionally non-autonomous element of 937 bp delimited by 30 bp perfect inverted terminal repeats. The element is flanked by the TA duplication typical of mariner elements in general. There are approximately 435 copies of TnM1a homologous elements per haploid genome. These elements appear, by Southern blot analysis, to be dispersed throughout the genome. Thirteen individual genomic clones with an average size of 15 kb, were found to contain only a single element each, which also suggests that the elements are not tightly clustered. Finally, mariner elements are neither inactivated by methylation nor sequestered into a methylated fraction of the genome.     

Blood zinc, copper, insulin and glucose levels in carbohydrate-sensitive and normal men given a sucrose or invert sugar tolerance test

Twelve carbohydrate-sensitive and 12 non-carbohydrate sensitive (normal) men were studied. Carbohydrate sensitivity was identified by hyperinsulinemic and normoglycemic responses to a sucrose load. In a blocked split-plot design, fasted subjects were given 2 g/kg body weight of sucrose or invert sugar, and responses of plasma zinc, copper, insulin, and glucose were determined. Erythrocyte zinc and copper also were measured. Blood samples were taken 0, 0.5, 1, 2, and 3 hours after the sugar loads were given. Plasma zinc, copper, insulin, and glucose did not differ significantly between the two sugar loads. Neither did erythrocyte zinc and copper differ significantly between the two load doses. Also, plasma zinc, copper, and glucose, as well as erythrocyte zinc and copper, did not differ significantly between the carbohydrate-sensitive and normal men. Plasma insulin was significantly higher in the carbohydrate-sensitive than the normal men. Plasma zinc did not change significantly between sampling times. Plasma copper declined progressively over the testing period. The greater the elevation of plasma glucose above the fasting level, the greater the plasma copper was depressed. Copper appears to be withdrawn from plasma after sugar loading to facilitate glucose uptake and metabolism.     

Complications in surgical patients: A comparison of methods for identifying occurrence

Because reporting of complications by physicians is not reliable, monitoring of the hospital course of surgical patients by nurses can improve effectiveness of identifying complications. Monitoring the course of only those patients who remain in the hospital more than four postoperative days will disclose 90 per cent of complications expected in all patients undergoing operation. Twenty hours per week of a nurse's time is sufficient to monitor 1,300 such patients annually. Identification of patients with large hospital bills will include most patients with complicated hospital courses but does not discriminate them from the large number of uncomplicated courses which also generate large hospital charges.     

Serotonin depolarizes type A and C primary afferents: an intracellular study in bullfrog dorsal root ganglion

Intracellular recordings were obtained from the somata of type A and C primary afferents in the isolated bullfrog dorsal root ganglion (DRG) preparation. Bath application of serotonin (5-HT) in concentrations of 0.25-1.0 mM led to slow and fast depolarizing responses. Slow, maintained 5-HT depolarizations were observed in 47% of type A and 70% of type C neurons. These slow depolarizations were associated with an underlying increase in input resistance (Rin). In some type A neurons, the Rin increase was masked by a decrease in Rin due to depolarization-induced rectification. The slow 5-HT depolarization of type A, but not type C neurons showed pronounced tachyphylaxis to repeated 5-HT applications. In type C afferents, serotonin's slow action was often accompanied by spontaneous firing. Manganese decreased slow 5-HT depolarizations of both cell types. A slow depolarization and excitation of type C afferents by methysergide and cinanserin was also observed. Fast transient 5-HT depolarizations accompanied by a rapid decrease in Rin were observed in 7% of type A and 24% of type C neurons. In some DRG cells the fast and slow depolarizations combined to form a biphasic response. The actions of 5-HT reported here resemble in some ways 5-HT responses recorded extracellularly from the spinal terminations of primary afferents.     

Infant communicating hydroceles—do they need immediate repair or might some clinically resolve?

Purpose

Infant hydroceles that are communicating by history (fluctuation in size) or examination (reducible fluid) are often repaired soon after presentation. We have followed a series of infant boys with such hydroceles and reviewed their early natural history.

Materials and Methods

Since 1998, we have followed 174 infant boys presenting with an apparent communicating hydrocele without immediate surgical repair. All boys were initially seen before 18 months of age and most (168) by 12 months. Most had been full term at delivery, although 32 had been premature (<37 weeks' gestational age) and 11 extremely so (<32 weeks). Most boys (120) had bilateral hydroceles at presentation.

Results

Of the 110 boys followed to disposition, 69 (62.7%) had complete resolution without surgery by a mean age of 11.7 months. Forty-one patients (37.3%) underwent surgery for correction at a mean age of 14 months because of persistence in size or development of a hernia. Six developed a hernia during observation, none of whom had any episode of incarceration. Only 2 patients with apparent resolution subsequently had recurrence with a hernia. Age at presentation and gestational age at birth showed no effect on resolution. The hydroceles of 64 boys had improved in size after a mean follow-up of 13.9 months when last seen.

Conclusions

Many infant hydroceles that are communicating by history or examination do resolve clinically without surgery and deserve observation. Progression to hernia was rare in our experience and did not result in incarceration. Consequently, little risk is taken by initial observation.     

Risk Assessment of Toxaphene and its Breakdown Products: Time for a Change?

Technical toxaphene (TT) was last used in commerce in about 1982. Any environmental exposure to toxaphene in this century is to environmentally degraded forms of toxaphene, termed weathered toxaphene. Several hundred chlorinated bornane congeners have been identified in technical toxaphene. The degradation of technical toxaphene to weathered toxaphene can result in various congener mixtures, but the primary mode of degradation is dechlorination. The U.S. Environmental Protection Agency (EPA) presently estimates the risk of exposure to toxaphene by relying upon rat and mouse toxicology studies performed on technical toxaphene. No adjustment is made for the dechlorination of toxaphene in the environment. The European Union (EU), however, has modeled toxaphene risks from eating fish with chlorinated bornane residues through a series of studies on toxaphene degraded by either ultraviolet light, or biodegradation in fish. The EU risk assessment relies upon rat liver studies in vivo and mouse in vitro studies on the inhibition of gap junction intercellular communication (GJIC). This article reviews the current state of knowledge of technical and weathered toxaphene toxicology. We discuss the various current methods and opportunities to advance the risk assessment of weathered toxaphene beyond the existing U.S. EPA assessment of technical toxaphene.     

Yield of Neck CT and Barium Esophagram in Patients with Globus Sensation

BACKGROUND AND PURPOSE:Globus sensation is common and difficult to treat. The purpose of our study was to compare the diagnostic and therapeutic efficacy of barium esophagram and neck CT in patients with isolated globus sensation, to determine which of these modalities should be preferred in the evaluation of this condition.MATERIALS AND METHODS:We retrospectively identified patients presenting with isolated globus sensation from January 1, 2005, to December 31, 2012, who underwent neck CT or barium esophagram. We calculated the proportion of patients with abnormal findings, tabulated the nature of the abnormality, and reviewed the medical records to determine whether imaging changed management.RESULTS:One hundred forty-eight neck CTs and 104 barium esophagrams were included. Five (3.4%) patients with neck CTs and 4 (3.9%) with barium esophagrams demonstrated significant findings related to the history of globus sensation. Of these, 1 (0.7%) neck CT and 1 (1.0%) barium esophagram resulted in a change in clinical management.CONCLUSIONS:Imaging evaluation of the patient with uncomplicated globus sensation is unlikely to identify clinically significant imaging findings and is very unlikely to result in a change in clinical management, with a combined therapeutic efficacy of 0.8%. Thus, the routine use of imaging in the evaluation of patients with globus sensation cannot be recommended.

Globus sensation (GS), an intermittent or persistent painless sensation of a foreign body or lump in the throat, is a long-lasting and often frustratingly difficult-to-treat clinical entity.¹ It is a relatively common condition, accounting for up to 4% of new referrals to otolaryngology clinics, with a prevalence of up to 35% in males and over 50% in females, with a relative peak in middle age.^2–4 A range of etiologies has been suggested and described, including lingual and tonsillar hypertrophy, psychogenic factors, cervical osteophytes, upper aerodigestive tract malignancy, thyroid disease, and esophageal motor disorders.^5–8 More recently, there has been increasing focus on gastroesophageal reflux disease as a cause of GS.^9–13 The myriad potential etiologies of GS have made it difficult to establish standard treatment and imaging strategies for affected patients.The imaging approach to the patient with GS varies widely in clinical practice. A neck CT, usually ordered with contrast, is well-suited to detect many structural causes of GS and is a useful tool to exclude a large upper aerodigestive tract malignancy, while a barium esophagram is well-suited for detailed evaluation of esophageal motility and mucosal and submucosal lesions of the esophagus. While a barium esophagram may also detect (but cannot exclude) intermittent esophageal reflux, if evaluation for esophageal reflux is of primary concern, then esophageal manometry, endoscopy, esophageal pH monitoring, or a trial of empiric therapy is the preferred diagnostic test.^14–16The imaging approach to the patient with GS varies widely in clinical practice. Because an evidence-based approach to imaging GS is lacking in current clinical practice, practitioner and locoregional biases strongly influence the decision to use neck CT or barium esophagram. This may adversely impact the clinical value of these studies because the value of a diagnostic test is largely dependent on the prevalence (or the clinician''s estimate of the pretest probability) of the target disorder, and abnormalities detectable on neck CT and barium esophagram are statistically unlikely etiologies in a general sample of patients with GS. Because overuse of diagnostic tests contributes to both the rising cost and the overall quality of health care, defining the value of diagnostic tests has become an important goal of health care reform. We conducted the present study to determine the incidence and nature of abnormalities on neck CT and barium esophagram examinations performed in the work-up of patients with isolated GS and to assess which imaging technique contributed most effectively to the clinical management of these patients.     

A biomechanical comparison of three lower extremity tendons for ligamentous reconstruction about the knee

Purpose: The purpose of this investigation was to evaluate 3 previously unreported allograft tendons for use in knee surgery. These are the doubled tibialis anterior (TA), doubled tibialis posterior (TP), and doubled peroneus longus (PL) tendons. Type of Study: A biomechanical evaluation of the properties of the TA, TP, and PL. Methods: Sixteen fresh-frozen cadaveric lower limbs were used for testing. All specimens had the TA, TP, and PL tendons harvested. All specimens were tested in a custom-designed hydraulic testing machine using dry ice clamps. Each tendon was elongated at a rate of 1 mm/s. Load and displacement were recorded with an analog to digital interface board. Stiffness, modulus of elasticity, and stress and strain at failure were calculated. Results: The average tested lengths of the TA, TP, and PL were 37 cm (range, 13–68 cm), 33 cm (range, 7–74 cm), and 42 cm (range, 17–69 cm), respectively. The average cross-sectional areas of the doubled TA, TP, and PL were 38 mm², 48 mm², and 37 mm², respectively. The average failure loads for the doubled TA, TP, and PL tendons were 3,412 N, 3,391 N, and 2,483 N, respectively. The maximum stresses of the 3 tendons did not differ significantly (85–108 Mpa). The TA had the greatest stiffness (344 N/mm), followed by the TP (302 N/mm) and the PL (244 N/mm). Previous authors have documented the biomechanical strength of grafts for ACL reconstruction between 1,700 and 2,900 Newtons. The ultimate tensile strength and stiffness reported for the TA and TP grafts exceeded that for all previously reported grafts, including the doubled semitendinosus-gracilis. Conclusions: The TA, TP, and PL tendons showed excellent biomechanical properties when compared with historical data evaluating other graft sources. The biomechanical properties observed for the TA, TP, and PL were noted in specimens despite an average age of 78.3 years.