Episodes of particle ejection from the surface of the active asteroid (101955) Bennu

Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances of particle ejection from the surface of (101955) Bennu, demonstrating that it is an active asteroid. The ejection events were imaged by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For the three largest observed events, we estimated the ejected particle velocities and sizes, event times, source regions, and energies. We also determined the trajectories and photometric properties of several gravitationally bound particles that orbited temporarily in the Bennu environment. We consider multiple hypotheses for the mechanisms that lead to particle ejection for the largest events, including rotational disruption, electrostatic lofting, ice sublimation, phyllosilicate dehydration, meteoroid impacts, thermal stress fracturing, and secondary impacts.

Pharmacological inhibition of TLR4 ameliorates muscle and liver ceramide content after disuse in previously physically active mice

Toll-like receptor 4 (TLR4) is a proposed mediator of ceramide accumulation, muscle atrophy, and insulin resistance in skeletal muscle. It is currently unknown whether pharmacological inhibition of TLR4, using the TLR4-specific inhibitor TAK-242 during muscle disuse, is able to prevent changes in intracellular ceramide species and consequently preserve muscle size and insulin sensitivity in physically active mice. To address this question, we subjected running wheel-conditioned C57BL/6 male mice (13 wk old; ∼10/group) to 7 days of hindlimb suspension (HS), 7 days of continued wheel running (WR), or daily injections of TAK-242 during HS (HS + TAK242) for 7 days. We measured hindlimb muscle morphology, intramuscular and liver ceramide content, HOMA-IR, mRNA proxies of ceramide turnover and lipid trafficking, and muscle fatty acid and glycerolipid content. As a result, soleus and liver ceramide abundance was greater (P < 0.05) in HS vs. WR but was reduced with TLR4 inhibition (HS + TAK-242 vs. HS). Muscle mass declined (P < 0.01) with HS (vs. WR), but TLR4 inhibition did not prevent this loss (soleus: P = 0.08; HS vs. HS + TAK-242). HOMA-IR was impaired (P < 0.01) in HS versus WR mice, but only fasting blood glucose was reduced with TLR4 inhibition (HS + TAK-242 vs HS, P < 0.05). Robust decreases in muscle Spt2 and Cd36 mRNA and muscle lipidomic trafficking may partially explain reductions in ceramides with TLR4 inhibition. In conclusion, pharmacological TLR4 inhibition in wheel-conditioned mice prevented ceramide accumulation during the early phase of hindlimb suspension (7 days) but had little effect on muscle size and insulin sensitivity.

Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU₆₉, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU₆₉ is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU₆₉'s origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

Neuromuscular Electrical Stimulation Combined with Protein Ingestion Preserves Thigh Muscle Mass But Not Muscle Function in Healthy Older Adults During 5 Days of Bed Rest

Short-term bed rest in older adults is characterized by significant loss in leg lean mass and strength posing significant health consequences. The purpose of this study was to determine in healthy older adults if the daily combination of neuromuscular electrical stimulation and protein supplementation (NMES+PRO) would protect muscle mass and function after 5 days of bed rest. Twenty healthy older adults (∼70 years) were subjected to 5 days of continuous bed rest and were randomized into one of two groups: NMES+PRO (n = 10) or control (CON) (n = 10). The NMES+PRO group received bilateral NMES to quadriceps (40 minutes/session, 3 × /day; morning, afternoon, and evening) followed by an interventional protein supplement (17 g). The CON group received an isocaloric equivalent beverage. Before and after bed rest, vastus lateralis biopsies occurred before and after acute essential amino acid (EAA) ingestion for purposes of acutely stimulating mechanistic target of rapamycin (mTORC1) signaling, a major regulator of muscle protein synthesis, in response to bed rest and NMES+PRO. Baseline (pre and post bed rest) muscle samples were also used to assess myofiber characteristics and gene expression of muscle atrophy markers. Thigh lean mass and muscle function were measured before and after bed rest. Five days of bed rest reduced thigh lean mass, muscle function, myofiber cross-sectional area, satellite cell content, blunted EAA-induced mTORC1 signaling, and increased myostatin and MAFbx mRNA expression. Interestingly, NMES+PRO during bed rest maintained thigh lean mass, but not muscle function. Thigh muscle preservation during bed rest with NMES+PRO may partly be explained by attenuation of myostatin and MAFbx mRNA expression rather than restoration of nutrient-induced mTORC1 signaling. We conclude that the combination of NMES and protein supplementation thrice a day may be an effective therapeutic tool to use to preserve thigh muscle mass during periods of short-term hospitalization in older adults. However this combined intervention was not effective to prevent the loss in muscle function.

A pilot study examining the impact of exercise training on skeletal muscle genes related to the TLR signaling pathway in older adults following hip fracture recovery

Older adults after hip fracture surgery experience progressive muscle atrophy and weakness, limiting full recovery. Further understanding of the molecular mechanisms in muscle with adaptation to exercise training in this vulnerable population is necessary. Therefore, we conducted a pilot study to investigate the skeletal muscle inflammatory and ceramide biosynthesis gene expression levels associated with the toll-like receptor (TLR) pathway before (Pre) and following a 3-mo multicomponent exercise training program in older adults (3M, 4F; 78.4 ± 13.3 yr; 25.5 ± 2.3 kg/m²) ~4 mo after repair from hip fracture (HipFx). Vastus lateralis biopsies from the surgical limb were obtained before (Pre) and after training. Molecular end points and muscle function data were also compared with matched nonexercise healthy controls (CON). As a follow-up analysis, we evaluated specific sphingolipid pools in HipFx and CON muscle. Following training, quadriceps cross-sectional area, strength, and 6-min walk (6MW) increased in the surgical limb (P < 0.05). Additionally, MYD88, TAK1, NFKB1, IL6, SPT2, and CERS1 gene expression decreased after training (P ≤ 0.05), but some remained elevated above CON levels. Interestingly, MYD88 mRNA was inversely correlated to quadriceps CSA, strength, and 6MW. Finally, muscle dihydroceramides and phosphoceramides in HipFx were lower than CON at Pre (P ≤ 0.05), but after training differences from CON were removed. Together, our pilot data support that exercise training alters skeletal muscle inflammation and ceramide metabolism associated with TLR signaling in older adults recovering from hip fracture surgery and may be related to improvements in muscle function recovery.

NEW & NOTEWORTHY

These pilot data demonstrate that 3 mo of exercise training in older adults recovering from hip fracture surgery was able to mitigate skeletal muscle gene expression related to inflammation and ceramide metabolism while also improving surgical limb lean tissue, strength, and physical function.

Intramyocellular ceramides and skeletal muscle mitochondrial respiration are partially regulated by Toll-like receptor 4 during hindlimb unloading

Physical inactivity and disuse result in skeletal muscle metabolic disruption, including insulin resistance and mitochondrial dysfunction. The role of the Toll-like receptor 4 (TLR4) signaling pathway in contributing to metabolic decline with muscle disuse is unknown. Therefore, our goal was to determine whether TLR4 is an underlying mechanism of insulin resistance, mitochondrial dysfunction, and skeletal muscle ceramide accumulation following muscle disuse in mice. To address this hypothesis, we subjected (n = 6-8/group) male WT and TLR4^-/- mice to 2 wk of hindlimb unloading (HU), while a second group of mice served as ambulatory wild-type controls (WT CON, TLR4^-/- CON). Mice were assessed for insulin resistance [homeostatic model assessment-insulin resistance (HOMA-IR), glucose tolerance], and hindlimb muscles (soleus and gastrocnemius) were used to assess muscle sphingolipid abundance, mitochondrial respiration [respiratory control ratio (RCR)], and NF-κB signaling. The primary finding was that HU resulted in insulin resistance, increased total ceramides, specifically Cer18:0 and Cer20:0, and decreased skeletal muscle mitochondrial respiration. Importantly, TLR4^-/- HU mice were protected from insulin resistance and altered NF-κB signaling and were partly resistant to muscle atrophy, ceramide accumulation, and decreased RCR. Skeletal muscle ceramides and RCR were correlated with insulin resistance. We conclude that TLR4 is an upstream regulator of insulin sensitivity, while partly upregulating muscle ceramides and worsening mitochondrial respiration during 2 wk of HU.

Heat-induced changes in intracellular Na+, pH and bioenergetic status in superfused RIF-1 tumour cells determined by23Na and31P magnetic resonance spectroscopy

The acute effects of hyperthermia on intracellular Na+ (Nai+), bioenergetic status and intracellular pH (pHi) were investigated in superfused Radiation Induced Fibrosarcoma-1 (RIF-1) tumour cells using shift-reagent-aided 23Na and 31P nuclear magnetic resonance (NMR) spectroscopy. Hyperthermia at 45 degrees C for 30 min produced a 50% increase in Na, a 0.42 unit decrease in pHi and a 40-45% decrease in NTP/P(i). During post-hyperthermia superfusion at 37 degrees C, pHi and NTP/P(i) recovered to the baseline value, but Na initially decreased and then increased to the hyperthermic level 60 min after heating. Hyperthermia at 42 degrees C caused only a 15-20% increase in Nai+. In the presence of 3 microM 5-(N-ethyl-N-isopropyl)amiloride (EIPA), an inhibitor of the Na+/H+ exchanger, the increase in Nai+ during 45 degrees C hyperthermia was attenuated, suggesting that the heat-induced increase in Nai+ was mainly due to an increase in Na+/H+ anti-porter activity. EIPA did not prevent hyperthermia-induced acidification. This suggests that pHi is controlled by other ion exchange mechanisms in addition to the Na+/H+ exchanger. EIPA increased the thermo-sensitivity of the RIF-1 tumour cells only slightly as measured by cell viability and clonogenic assays. The hyperthermia-induced irreversible increase in Nai+ suggests that changes in transmembrane ion gradients play an important role in cell damage induced by hyperthermia.

Effects of hyperglycemia on oxygenation, radiosensitivity and bioenergetic status of subcutaneous RIF-1 tumors

Since tissue oxygen tension is a balance between delivery and consumption of oxygen, considerable effort has been directed at increasing the former and/or decreasing the latter. Techniques to decrease the rate of cellular oxygen consumption (increasing the distance oxygen can diffuse into tissues) include increasing glycolysis by administering supra-physiologic levels of glucose. We have examined the effect of hyperglycemia produced by intravenous glucose infusion on the tissue oxygenation and radiation response of subcutaneously implanted murine radiation induced fibrosarcomas (RIF-1). A 0.3 M glucose solution was delivered via tail vein injection according to a protocol that maintained glucose at a plasma concentration of 17+/-1 mM. The effect of this treatment on radiation response (clonogenic and growth delay studies), tumor oxygenation (needle electrode pO2 and 2-[2-nitro-1H-imidazol-1-yl]-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF5) binding), and tumor bioenergetics and pH (31P NMR spectroscopy) was examined. Systemic measurements included hematocrit and blood glucose and lactate concentrations. The results of these studies suggest that these subcutaneously implanted RIF-1 tumors are both radiobiologically and metabolically hypoxic and that intravenous glucose infusion is not an effective method of modifying this metabolic state.

Use of propofol sedation in a pediatric emergency department: a prospective study

The purpose of this study was to determine the efficacy and safety of propofol sedation for pediatric procedures in the emergency department. For patients needing painful procedures, propofol was administered intravenously. Vital signs, complications, and time to recovery were recorded. Patient amnesia and parent, patient, and operator satisfaction with sedation were assessed. The mean age was 7.4 years; 65% were male. Most underwent fracture reduction. Mean total dose was 3.3 mg/kg. Thirty percent experienced desaturation. One required assisted ventilation. Most had decreases in blood pressure. Mean recovery time was 18 minutes. Satisfaction with sedation was rated "excellent." Propofol was an effective sedation with minimal complications in the emergency department setting.

A prospective evaluation of the clinical presentation of pediatric pelvic fractures

BACKGROUND

We sought to describe pediatric, blunt trauma patients with pelvic fracture (PF) and to evaluate pelvis examination sensitivity and specificity.

METHODS

We conducted a prospective study of blunt trauma patients at a Level I pediatric trauma center. A pediatric emergency medicine physician attempted to diagnose a PF, solely on the basis of the history and pelvis examination. Patients with blunt trauma but no pelvic fracture (NPF) were used as controls.

RESULTS

We enrolled 140 patients (16 PF, 124 NPF), and no significant differences were found regarding median age, gender, injury mechanism, acuity, and medical outcome. Approximately 25% of PF patients had iliac-wing fractures; 37%, single pelvic ring; 25%, double pelvic ring; and 13%, acetabular fractures. Eleven patients with PF had an abnormal pelvis examination (69% sensitivity), compared with six NPF patients (95% specificity, negative predictive value 0.91).

CONCLUSION

Pediatric patients with PF have low mortality and few complex fractures. The pelvis examination appears to have both high specificity and negative predictive value.

The addition of ceftriaxone to oral therapy does not improve outcome in febrile children with urinary tract infections

OBJECTIVE

To determine whether the addition of a single dose of ceftriaxone sodium to a 10-day course of trimethoprim and sulfamethoxazole hastens urine sterilization or resolution of clinical symptoms in febrile children with urinary tract infections.

DESIGN

Prospective, single-blind, randomized study.

SETTING

Tertiary care children's hospital emergency department.

PATIENTS

Febrile children aged 6 months to 12 years with a presumptive urinary tract infection based on history, physical examination, and urinalysis findings.

INTERVENTIONS

A history was taken, a physical examination and urinalysis and culture were performed, and a white blood cell count and erythrocyte sedimentation rate were obtained. Children were randomized to receive an intramuscular dose of ceftriaxone then 10 days of trimethoprim-sulfamethoxazole (IM + PO group) or oral trimethoprim-sulfamethoxazole alone (PO group). After receiving study medication, patients were discharged from the hospital to return in 48 hours for a follow-up evaluation and urine culture. Treatment failure was defined as the persistence of a positive culture at 48 hours or the need for hospital admission for intravenous rehydration or antibiotic therapy.

RESULTS

Sixty-nine children were enrolled, 34 in the IM + PO group and 35 in the PO group. The 2 groups were similar at the initial visit with respect to age, sex, clinical degrees of illness, white blood cell count, and erythrocyte sedimentation rate (P>.05). At the 48-hour follow-up visit, there were no differences between the 2 treatment groups in resolution of vomiting, fever, general appearance, abdominal tenderness, and hydration state (P>.05). There were 9 treatment failures, 4 in the IM + PO group and 5 in the PO group (P =.93).

CONCLUSION

The addition of a single dose of intramuscular ceftriaxone to a 10-day course of oral trimethoprim-sulfamethoxazole for urinary tract infection with fever resulted in no difference at 48 hours in the urine sterilization rate, degree of clinical improvement, or subsequent hospital admission rate.

Do parents choose appropriate automotive restraint devices for their children?

This study aims to describe parental choices of childhood automotive restraints and compare them with guidelines based on weight and height. Parents were surveyed and their children's heights and weight were measured. Results indicated that many parents believed their child fit a lap or shoulder belt when their children were too short to fit these devices. For children weighing < 40 pounds, 45% of parents believed the lap belt fit. Thirteen percent of 4-7-year-olds used booster seats, appropriate for 72% by sitting height criteria; and 33% of children < or = 7 years used the lap/shoullder belt, appropriate for 8% by sitting height criteria. Implications are that parental perceptions of fit may lead to inappropriate restraint choices for children. Practitioners should discuss child restraint use with parents in the context of their child's weight and height.

Appendiceal perforation in children diagnosed in a pediatric emergency department

OBJECTIVE

To determine the incidence of appendiceal perforation (AP) among children with acute appendicitis (AA) and determine factors associated with AP.

DESIGN

Retrospective chart review.

SETTING

Emergency department (ED) of Primary Children's Medical Center (PCMC).

PATIENTS

131 children less than 17 years of age with AA diagnosed in the PCMC ED.

RESULTS

The overall rate of AP was 47%. One hundred eleven (85%) children with AA were correctly diagnosed on their first ED visit. Patients with AP had a significantly (P < 0.05) lower median age (8.0 vs 11.0 years), longer duration of illness (3.0 vs 1.4 days), greater incidence of vomiting and fever by history (91% vs 69% and 83% vs 58%, respectively), higher median temperatures (39.0 degrees vs 38.3 degrees C), and higher proportions of leukocyte (WBC) band forms (14% vs 5%). Patients with AP did not differ from those without AP with respect to total WBC count, hour of arrival, or number of ED visits.

CONCLUSIONS

The rate of AP among pediatric patients with AA is greater among younger children and is associated with vomiting, prolonged illness, and higher body temperatures. Unexpectedly, patients with AP did not have higher total WBC values, more frequent late night arrivals, a longer time interval prior to surgery, or more ED visits prior to diagnosis. These findings suggest that efforts to decrease the rate of AP should be directed toward heightening awareness among primary care physicians regarding the high rate of AP in children, with an emphasis on early ED and surgical referral.

Binding relationships of membrane tethering components. The giantin N terminus and the GM130 N terminus compete for binding to the p115 C terminus

By forming a molecular tether between two membranes, p115, giantin, and GM130 may mediate multiple Golgi-related processes including vesicle transport, cisternae formation, and cisternal stacking. The tether is proposed to involve the simultaneous binding of p115 to giantin on one membrane and to GM130 on another membrane. To explore this model, we tested for the presence of the putative giantin-p115-GM130 ternary complex. We first mapped p115-binding site in giantin to a 70-amino acid coiled-coil domain at the extreme N terminus, a position that may exist up to 400 nm away from the Golgi membrane. We then generated glutathione S-transferase (GST) fusion proteins containing either giantin's or GM130's p115 binding site and tested whether such proteins could bind p115 and GM130 or bind p115 and giantin, respectively. Unexpectedly, GST fusions containing either the giantin or the GM130 p115 binding site efficiently bound p115, but the p115 bound to GST-giantin did not bind GM130, and the p115 bound to GST-GM130 did not bind giantin. To explain this result, we mapped the giantin binding site in p115 and found that it is located at the C-terminal acidic domain, the same domain involved in binding GM130. The presence of a single binding site in p115 for giantin and GM130 was confirmed by demonstration that giantin and GM130 compete for binding to p115. These results question a simple tethering model involving a ternary giantin-p115-GM130 complex and suggest that p115-giantin and p115-GM130 interactions might mediate independent membrane tethering events.

Costs of sedation using oral midazolam: money, time, and parental attitudes

OBJECTIVE

Many agents suitable for pediatric outpatient sedation have been identified and compared, but less data have appeared on the effect of sedation use on Emergency Department (ED) length of stay (LOS) or visit costs. We sought to discover the relationship between one commonly used method of sedation, orally administered midazolam, and ED LOS and visit costs. Parents were then surveyed to determine their attitudes toward sedation given knowledge of these costs.

METHODS

All ED patients under 10 years of age seen in a pediatric ED during April and May of 1996 for repair of lacerations <2.5 cm in length were identified via retrospective chart review. Children were excluded if they had other significant injuries, received sedatives other than oral midazolam, or were repaired by non-ED physicians. Preliminary cost and LOS data from this review was used to create a parental survey measuring attitudes toward the costs of an unnamed form of sedation (not mentioning oral midazolam). A convenience sample of parents in an ED waiting room were asked if they would want sedation administered to a child needing sutures if this increased the visit cost by $100 and/or increased LOS by 30 minutes. Parents were then asked to re-answer these questions assuming that the sedation medication was effective only 50% of the time.

RESULTS

Of 120 patients meeting entry criteria, 57 (48%) received oral midazolam. Children sedated with this agent were significantly younger (3.6 vs. 4.6 years, P = 0.015), had more layered repairs (30% vs. 14%, P = 0.047), and more facial lacerations (84% vs. 63%, P = 0.01) when compared with nonsedated patients. Mean LOS for patients with simple lacerations receiving oral midazolam increased by 17.1 minutes (P = 0.03) compared with nonsedated children; for layered repairs, the mean increase was 30.9 minutes (P<0.05). The use of oral midazolam did not effect physician charges, but did significantly increase mean combined nurse/hospital charges and total charges by 73 to 87 dollars, depending on laceration type (P<0.001 all cases). Of 81 parents surveyed, 81% said that they would be willing to wait 30 extra minutes for sedation to be used; this figure fell to 73% if sedation was effective 50% of the time. Seventy-five percent of parents were willing to pay $100 extra for sedation; 67% if sedation was effective only half the time. Willingness to endure a longer LOS or pay increased charges was not associated with parental sex or insurance status.

CONCLUSION

The use of oral midazolam significantly increases ED visit LOS and cost. This information is important to review with parents when discussing sedation options. Up to one third of parents surveyed would not want to wait extra time or pay extra money for sedation to be administered, especially if the efficacy of the chosen method was not assured.

Molecular cloning, characterization, and dynamics of rat formiminotransferase cyclodeaminase, a Golgi-associated 58-kDa protein

A peripherally associated 58-kDa Golgi protein (58K) of unknown function has been previously described (Bloom, G. S., and Brashear, T. A. (1989) J. Biol. Chem. 264, 16083-16092). To molecularly characterize 58K, we used a monoclonal anti-58K antibody (monoclonal antibody 58K-9) to screen a rat liver cDNA expression library. Positive clones were isolated, characterized, and partially sequenced. The obtained sequences show a high level of identity with sequences of porcine formiminotransferase cyclodeaminase (FTCD), suggesting that 58K is rat FTCD. Rat FTCD is structurally similar to porcine FTCD, a metabolic enzyme involved in conversion of histidine to glutamic acid, and exists in dimeric, tetrameric, and octameric complexes resistant to proteolysis. To define parameters of FTCD association with the Golgi, comparison of its behavior with various Golgi and ER-to-Golgi intermediate compartment marker proteins was examined under specific conditions. The results show that extraction parameters of FTCD are similar to those of GM130, a tightly associated Golgi matrix protein. FTCD appears to be a dynamic component of the Golgi, and a proportion of FTCD molecules cycle between the Golgi and earlier compartments of the secretory pathway. FTCD remains associated with Golgi fragments during microtubule disruption and is not released into cytosol during brefeldin A treatment. Instead, FTCD relocates from the Golgi, but the time course of its redistribution is distinct from that of mannosidase II relocation. FTCD is already dispersed into small punctate structures at a time when mannosidase II is still largely localized to Golgi structures. FTCD is not observed in tubules originating from the Golgi and containing mannosidase II. Instead, it appears to redistribute in small vesicles arranged in a linear "pearls on a string" pattern. These results suggest that FTCD relocation is temporally and spatially distinct from mannosidase II relocation and that FTCD provides a novel marker to study Golgi dynamics.

Management of febrile children with urinary tract infections

This study of the management of children with fever and urinary tract infection (UTI) was conducted to identify factors associated with initial admission, outpatient treatment, and outpatient treatment failure. A retrospective chart review identified children 3 months to 16 years of age with an emergency department (ED) diagnosis of cystitis, pyelonephritis, or UTI, a positive urine culture, and an ED temperature of >38 degrees C. Sixty-nine patients (90% female) were studied; 19% were admitted initially. Age younger than 2 years was associated with admission (P < .001). Of those initially discharged, 63% received parenteral antibiotics (usually intramuscular ceftriaxone), followed by oral antibiotics; 9% failed outpatient treatment. Outpatient failure was associated with higher initial temperatures (median 40.1 degrees C v 39.2 degrees C, P=.03, Mann-Whitney U) but was unrelated to age, initial white blood cell count, or use of parenteral antibiotics. These results indicate that most children with fever and UTI do not require hospital admission; those with temperatures of > or = 40 degrees C are at increased risk for outpatient failure.

The membrane transport factor TAP/p115 cycles between the Golgi and earlier secretory compartments and contains distinct domains required for its localization and function

The mammalian protein TAP/p115 and its yeast homologue Uso1p have an essential role in membrane traffic (Nakajima et al., 1991; Waters et al., 1992; Sztul et al., 1993; Rabouille et al.; 1995). To inquire into the site and mechanism of TAP/p115 action, we aimed to localize it and to identify domains required for its function. We show that in interphase cells, TAP/p115 localizes predominantly to the Golgi and to peripheral structures that represent vesicular tubular clusters (VTCs) involved in ER to Golgi transport. Using BFA/ nocodazole treatments we confirm that TAP/p115 is present on ER to Golgi transport intermediates. TAP/ p115 redistributes to peripheral structures containing ERGIC-53 during a 15 degreesC treatment, suggesting that it is a cycling protein. Within the Golgi, TAP/p115 is associated with pleiomorphic structures on the cis side of the cis-Golgi cisterna and the cis-most cisterna, but is not detected in more distal compartments of the Golgi. TAP/p115 binds the cis-Golgi protein GM130, and the COOH-terminal acidic domain of TAP/p115 is required for this interaction. TAP/p115 interaction with GM130 occurs only in the Golgi and is not required for TAP/p115 association with peripheral VTCs. To examine whether interaction with GM130 is required to recruit TAP/p115 to the Golgi, TAP/p115 mutants lacking the acidic domain were expressed and localized in transfected cells. Mutants lacking the GM130-binding domain showed normal Golgi localization, indicating that TAP/p115 is recruited to the Golgi independently of its ability to bind GM130. Such mutants were also able to associate with peripheral VTCs. Interestingly, TAP/p115 mutants containing the GM130-binding domain but lacking portions of the NH2-terminal region were restricted from the Golgi and localized to the ER. The COOH-terminal domain required for GM130 binding and the NH2-terminal region required for Golgi localization appear functionally relevant since expression of TAP/p115 mutants lacking either of these domains leads to loss of normal Golgi morphology.

Epidemiological analysis of injury in one year of Canadian professional rodeo

OBJECTIVES

To document injury rates and treatment use during one competitive season of Canadian professional rodeo.

DESIGN

Prospective cohort study.

SETTING

Canadian professional rodeo competition.

SUBJECTS

Competitors, included professional cowboys from Australia, Brazil, New Zealand, the United States, and Canada.

METHODS

Data were gathered prospectively at 15 of 68 professional rodeos in Canada, constituting 22% of all Canadian professional rodeos. Data were collected by four certified athletic therapists using a standardized form.

MAIN RESULTS

Overall, 94 athletes were injured during 3,882 individual competitor exposures (CEs). The composite injury rate was 2.3 per 100 CEs. This rate is lower than that reported in contact sports. Within the context of rodeo injuries, bareback riders and bull riders had similar high injury rates (4.6 and 3.6 per 100 CEs, respectively). Saddle bronc riders and steer wrestlers had moderate injury rates (1.4 and 0.9 per 100 CEs, respectively), whereas calf ropers had low injury rates (0.5 per 100 CEs). The knee and ankle were the most frequently treated sites of the body, followed by the shoulder, elbow, and lower back. Acute injury care and prophylactic taping were the most frequent services provided.

CONCLUSIONS

In order to study injury patterns in more detail and to assess risk factors for injury, a larger scale epidemiological study should be undertaken. Through such risk-based analysis, preventative strategies could be identified.

Transcytosis-associated protein (TAP)/p115 is a general fusion factor required for binding of vesicles to acceptor membranes

Transcytosis-associated protein (TAP) is found on transytotic vesicles (TCVs) and is required for their fusion with the target membrane. We developed a cell-free assay capable of differentiating targeting/binding of TCVs to membrane from later fusion events. We found that TAP mediates stable association of TCVs with the target membrane. The sequence of rat liver TAP (959-amino acid open reading frame) encodes a protein that contains (i) an N-terminal region (amino acids 1-649), (ii) an internal region with several coiled-coil stretches (amino acids 650-930), and (iii) a C-terminal acidic region (amino acids 931-959). Comparisons between TAP and other sequences indicate that TAP is identical to p115, a protein involved in cis to medial Golgi transport, and homologous to Uso1p, a yeast protein involved in endoplasmic reticulum to Golgi transport. Our findings suggest that TAP/p115/Usop1 is a general factor acting within the secretory and endocytic pathways to bind transport vesicles prior to membrane fusion.

Comparison of a recombinant endotoxin-neutralizing protein with a human monoclonal antibody to endotoxin for the treatment of Escherichia coli sepsis in rats

A recombinant endotoxin-neutralizing protein (ENP) from Limulus polyphemus and a monoclonal IgM anti-lipid A antibody (HA-1A) were compared in a rat model of Escherichia coli sepsis. One hour after intraperitoneal challenge with 10(6) cfu of E. coli O18ac K1, animals were sensitized to endotoxin with lead acetate and treated with ENP, HA-1A, or saline, followed by ceftriaxone and gentamicin. Before treatment, 95% of rats had high-grade bacteremia and high serum endotoxin concentrations, which were similar in all treatment groups (P > .60). One hour after treatment, there was no bacterial growth in any blood sample, and endotoxin concentrations were significantly lower in the ENP group than in the HA-1A and saline groups (P < .01). At 24 h after challenge, survival in the ENP group was significantly higher than in the HA-1A saline group (P < .001). ENP improved survival in a rat model of E. coli sepsis with high mortality despite effective antibiotic therapy.

Research note: a lack of response to pantothenic acid supplementation to a corn and soybean meal broiler diet

Two 21-day battery studies were conducted to determine whether a corn and soybean meal diet without pantothenic acid supplementation was adequate for growth and feed efficiency of broilers. In each experiment, 64 1-day-old broiler chicks (32 male and 32 female) were assigned to each of six dietary treatments. The basal diet was supplemented with 0, .3, .6, 2.4, 4.8, and 14.4 mg of supplemental pantothenic acid/kg of diet. Each diet in both experiments was fed to eight pens containing four females and four male day-old Arbor Acres broiler chicks. The basal diet contained 22.3% protein and 4.74 mg/kg pantothenic acid by analysis. No improvement in growth or feed efficiency was obtained from any level of pantothenic acid supplementation.

Spectrum and frequency of pediatric illness presenting to a general community hospital emergency department

Knowledge of the range of pediatric illness presenting to a general emergency department (ED) is needed to optimize the quality of care delivered there. It was hypothesized that the pediatric population treated at a general ED exhibited a broad range of medical complaints, while differing significantly from children seen in a pediatric ED. General ED records from 1 week each season were reviewed, and patient age, chief complaint, diagnosis, time of arrival, season, and disposition were recorded. Data on 874 patients were analyzed and compared with pediatric ED data. General ED patient age affected chief complaint, diagnosis, and admission rate (9.5% less than or equal to 1 year admitted vs 2.6% greater than 1 year, P less than .001). General ED patients were older (7.9 vs 6.0 years, P less than .001) and admitted less frequently (3.8% vs 11%, P less than .001). Admission rates varied by arrival time only at the general ED, where minor trauma was more common (41% vs 22%, P less than .001). It is concluded that a wide range of pediatric illness is treated in a general ED, supporting the decision to have pediatric emergency physicians on staff, and that significant differences exist in the spectrum and frequency of pediatric illness seen in a general ED and pediatric ED.

Humor in the pediatric emergency department: a 20-year retrospective

Humorous events often take place in pediatric emergency departments without being recorded. A written account of amusing situations occurring in an emergency department has been compiled over 20 years by personnel at a large urban children's hospital. Data from this reference were analyzed for humorous content and presented in the following categories: most interesting chief complaints, suspicious sounding chief complaints, favorite telephone inquiries, and illustrative cases. This study demonstrates that an emergency department may be a fertile source of medical humor. Recognition of these statements and events helps to relieve the stress of medical training and emergency department work.

A lack of fluctuation in xanthophyll concentrations in blood in laying hens at night and absence of pigmentation rings in the yolk

Alternate white and yellow layers in the yolk are described in most textbooks. However, it was impossible to distinguish the presence of these layers when hard-cooked yolks from hens fed commercial type diets were examined. Serum xanthophyll concentrations were measured at different times during a 24-h period. Concentrations did not vary significantly due to time of day.

The effect of gold treatment on monocyte interleukin-1 production in rheumatoid arthritis. A prospective study

Monocyte interleukin-1 (IL-1) production in vitro was studied in 49 patients with rheumatoid arthritis (RA) and 31 controls. Twenty-six of the RA patients were studied prospectively for up to 12 months after beginning chrysotherapy. About half of the patients (group 1) exhibited pretreatment levels of monocyte IL-1 secretion (as measured by bioassay or B-IL-1) significantly higher than that of the controls. Immunoreactive IL-1 (IR-IL-1) levels, however, were similar to controls. Clinical improvement in this group of patients was modest and transient but could be associated with a fall in the level of IL-1 (B-IL-1 and IR-IL-1) secretion. Other RA patients (group 2) appeared to have normal or reduced pretreatment levels of IL-1 secretion. Chrysotherapy resulted in significant clinical improvement within 3 months, and this was associated with an increase in IL-1 (both B-IL-1 and IR-IL-1) secretion by the patients' blood monocytes to normal or supranormal levels. Thus these two groups of RA patients (which differed only in the average duration of disease) had different prognoses in relation to chrysotherapy and the effect of chrysotherapy-induced remission on monocyte IL-1 secretion was opposite. These results suggest that monocyte IL-1 production in vitro reflects changes secondary to the anti-rheumatic effects of chrysotherapy.

Cytokine regulation of human monocyte interleukin-1 (IL-1) production in vitro. Enhancement of IL-1 production by interferon (IFN) gamma, tumour necrosis factor-alpha, IL-2 and IL-1, and inhibition by IFN-alpha

IL-1 production (secreted and cell-associated) was measured in monocyte cultures stimulated by a variety of agents in vitro. Monocytes either adherent to conventional plastic culture plates in serum-free conditions, or in suspension in culture medium containing serum were stimulated to produce IL-1 during culture. In non-adherent, serum-free conditions, monocytes produced very low or undetectable amounts of IL-1 during 20 h of culture. Lipopolysaccharide (LPS) induced equivalent amounts of secreted and cell-associated IL-1, although at very low concentrations more cell-associated IL-1 was produced. IL-1 production in response to LPS could be augmented by crude lymphokine, IFN-gamma, or tumour necrosis factor (TNF) alpha. TNF-alpha preferentially augmented the production of cell-associated IL-1 in LPS-stimulated cultures. TNF-alpha induced a significant amount of IL-1 (mainly cell-associated) directly but could also induce IL-1 secretion when combined with IL-2 or IFN-gamma, or when in the presence of serum. IL-2 acted synergistically with low concentrations of IFN-gamma or IL-1 to induce significant levels of IL-1 production. IFN-alpha did not induce any IL-1 production, but was a potent inhibitor of IL-1 production induced by a variety of stimuli. These results suggest that IL-1 production may be enhanced or reduced by different cytokines at concentrations likely to be found in chronic inflammatory lesions.

The effect of gold sodium thiomalate and auranofin on lipopolysaccharide-induced interleukin-1 production by blood monocytes in vitro: variation in healthy subjects and patients with arthritis

The anti-rheumatic gold compounds gold sodium thiomalate (GST) and auranofin (AF) have variable and often unpredictable effects in patients treated for arthritis. As inhibition of interleukin-1 (IL-1) production may be an important effect of these drugs, we investigated their effect on IL-1 production by lipopolysaccharide (LPS) stimulated monocytes in a serum-free, non-adherent culture system. A bi-modal effect was observed: low concentrations (GST 10-250 ng/ml and AF 1-100 ng/ml) potentiated IL-1 production, and higher concentrations (GST 200-1000 ng/ml and AF10-500 ng/ml) inhibited it. This bi-modal effect was observed for both secreted and cell-associated IL-1 activity with the exception that GST failed to inhibit cell-associated IL-1 generation. The potentiating effect was dependent on the continuous presence of gold for at least the first few hours after LPS stimulation. The inhibitory effect of GST was dependent on its presence after LPS stimulation while that of AF was evident even if cells were pretreated with AF and washed before exposure to LPS. There was considerable individual variation in IL-1 production in response to LPS as well as in the effects of gold on cells from both healthy individuals and patients with arthritis. There was also some overlap in the range of concentrations of gold that potentiated and inhibited IL-1 production, and there was relative insensitivity to the inhibitory effects of gold in certain individuals. These results may explain some of the variability in the response of patients to chrysotherapy and support further studies to see if these in vitro effects might predict clinical response to gold.

Seizure disorders in autism

Several reports have suggested that autistic individuals are at greater risk for developing seizure disorders, particularly in adolescence. In this study the frequency of seizures in a series of 192 autistic individuals was examined; 21% of cases had exhibited a seizure disorder. Seizure disorders were more common among individuals with lower IQ. Age specific incidence revealed a 3- to 22-fold increase in risk for seizure relative to the normal population. In contrast to previous studies, risk for developing seizures was highest during early childhood although it was also elevated during early adolescence.

Guidelines for return to activity after injury

Complete and effective rehabilitation is dependent on many factors and may be identified and measured by eight objectives. Use of these objectives should help to prevent many of the common errors in rehabilitation. Of these eight objectives, the authors concentrate on development of specific sports-related biomechanical skill patterns, an objective that is frequently neglected. Analysis of the specific demands of each sport for each athlete is required to tailor rehabilitation protocols as well as to provide a standard to determine when the athlete can return. Progressive sports-specific activity will help to return the athlete safely to activity.

Tumor cell heterogeneity in multiple myeloma: antigenic, morphologic, and functional studies of cells from blood and bone marrow

Tumor cells from six patients with immunoglobulin G (IgG) multiple myeloma were analyzed for surface antigens, cytoplasmic paraprotein, morphology, and response to various culture conditions. The tumor marker was the paraprotein idiotype. Low numbers of tumor cells were found in the blood of most of the patients. In some patients, the circulating tumor cells were solely B lymphocytes, whereas in other patients, they were lymphoid, lymphoplasmacytoid, and plasmacytoid. Dual surface antigen analysis of blood and bone marrow cells confirmed that the tumor may be composed of a spectrum of cell types. Thus, cells may range from surface-idiotype+,CD19+,CD20+, PCA-1-,cytoplasmic-idiotype- lymphocytes, to CD19-,PCA-1+,cytoplasmic-idiotype+ plasma cells that are surface-idiotype- or weakly surface-idiotype+. In one patient, some of the tumor cells co-expressed surface idiotype and CD10. The tumor B lymphocytes were activated in vitro to synthesize paraprotein by pokeweed mitogen (PWM), and by low molecular weight B cell growth factor (BCGF). In contrast, spontaneous synthesis of paraprotein by more mature tumor cells was inhibited by agents that also inhibit nonmyeloma plasma cells. These agents included PWM, gamma interferon, and phorbol ester. The results demonstrate that in multiple myeloma there exist different tumor cell types that are similar, by a variety of criteria, to normal B lineage cells at different stages of differentiation. Thus, further evidence is provided for the hypothesis of myeloma cell differentiation.

Effects of CKS-17, a synthetic retroviral envelope peptide, on cell-mediated immunity in vivo: immunosuppression, immunogenicity, and relation to immunosuppressive tumor products

CKS-17 is a heptadecapeptide corresponding to a region highly conserved in retroviral transmembrane proteins such as p15E. Because a relationship had previously been determined between p15E and immunosuppressive tumor cell products, we examined the effect of CKS-17, control peptides and conjugates thereof on the expression of cell-mediated immunity (delayed-type hypersensitivity, DTH) in mice. Conjugates of CKS-17 inhibited DTH reactions to sheep erythrocytes in the feet of mice. The degree of inhibition was dose-dependent. Unconjugated CKS-17 had almost no effect, and control peptide conjugates had no inhibitory effect. Immunization of mice with CKS-17 conjugates, but not with control conjugates, rendered them resistant to the depression of DTH reactions, not only by CKS-17 conjugates, but also by products of cultured tumor cells. CKS-17 conjugates, but not control conjugates, also depressed the cellular inflammatory reactions induced in mouse footpads by concanavalin A (ConA) and immunized mice against the depression of ConA reactions by products of cultured tumor cells. Injections of globulin from sera of mice immunized with CKS-17 conjugates conferred upon normal recipients resistance to the depression of footpad reactions to ConA by products of cultured tumor cells. Globulin from sera of normal mice or control immunized mice did not confer such resistance. Thus conjugates of a synthetic peptide not only mimic the immunosuppressive effects of tumor products in vivo, but can also immunize mice against those effects.

Interleukin-1 secretion by peripheral blood monocytes and synovial macrophages from patients with rheumatoid arthritis

Blood monocytes and synovial fluid and tissue macrophages were examined for their ability to produce interleukin-1 (IL-1) measured in a mouse thymocyte proliferation assay. Spontaneous production of IL-1 by monocytes from patients with rheumatoid arthritis (RA) or ankylosing spondylitis was higher than that by cells from normal subjects, patients with osteoarthritis or patients with RA treated with gold. IL-1 production in response to LPS stimulation was similar in all groups. Spontaneous IL-1 production by synovial fluid macrophages from patients with RA was similar to that of their monocytes, but the response to LPS was smaller. Synovial tissue macrophages produced little IL-1. Similar results were obtained in assays of fibroblast proliferation.

Depression of cell-mediated immunity by tumour cell products: induction of resistance by immunotherapeutically active extracts of bovine ocular squamous cell carcinoma

Tumours produce substances that inhibit the expression of cell-mediated immunity, in the form of delayed-type hypersensitivity in mice. Phenol-saline extracts of bovine ocular squamous cell carcinoma (BOSCC) which have immunotherapeutic activity in cattle were able to immunize mice against this depressive effect. Such immunization was effective against products of BOSCC, a spontaneous rat tumour, three of four human tumour cell lines and (in other experiments) mouse tumours. Phenol-saline extracts of mouse tumour cell lines were immunogenic (protective against depression of delayed-type hypersensitivity) in mice. Fractions of BOSCC phenol-saline extracts which were immunotherapeutically active in cattle were generally also protective in mice. The protective activity was lost after treatment with proteinase K, and was present in the supernatant after precipitation with 55% ammonium sulphate. It was not affected by treatment with RNase or DNase or by heating to 50 degrees C for 2 h. It was present in gel filtration fractions with an apparent molecular weight of 10,000-37,000 daltons. The immunogenic factor in mice and the immunotherapeutic factor in cattle may be related to each other.

Mast cell granules cause proliferation of human microvascular endothelial cells

To investigate the possible role of mast cells in blood vessel formation, rat mast cell granules were studied for their proliferative effect on human microvascular endothelial cells. It was found that granules had a marked proliferative effect and that most of this activity was restricted to a dialyzable fraction. The dialyzable mast cell granule constituent histamine was found to be mitogenic, an effect that was shown with the use of specific agonists and antagonists to be mediated through an H1 receptor. H1 antagonists reduced the proliferation caused by the untreated mast cell granules to the level of proliferation caused by dialyzed granules, suggesting that all the dialyzable mitogenic activity was due to histamine. Histamine was also shown to cause proliferation of cells that were growth arrested by serum deprivation, suggesting that it is an endothelial growth factor. The compound responsible for the undialyzable mitogenic activity could not be identified but was shown not to be mast cell heparin. This demonstration of mast cell granule-induced endothelial proliferation suggests that the mast cell may be of importance in the process of angiogenesis.

Endothelial cell enhancement of PWM induced immunoglobulin synthesis by peripheral blood mononuclear cells

The effect of various exogenous cells on the in-vitro PWM stimulation of immunoglobulin synthesis by normal human peripheral blood mononuclear cells was investigated. The accessory cells tested were bovine and human endothelial cells, bovine and human fibroblasts, normal human monocytes, and a monocyte cell line U937. Bovine and human endothelial cells boosted PWM-induced IgG and IgM synthesis, sometimes threefold. The enhancement was maintained over the 7-11 day period of culture and probably required cell to cell contact. It was not seen with the other cell types added and was, therefore, unlikely to be a consequence of an allogeneic or a xenogeneic stimulation, or a nonspecific 'feeder cell' effect.

Effects of cyclosporin A on the production of experimental anti-erythrocyte autoantibodies in mice

Mice were treated with cyclosporin A (CsA) (25-100 mg/kg daily, by mouth) during the induction of autoantibodies to erythrocytes by means of injections of rat erythrocytes. A high dose of CsA inhibited autoantibody production whereas a low dose temporarily potentiated it. Cell transfer and anti-Thy 1.2 treatment indicated the presence of suppressor T cells in the spleens of immunized mice. Their formation was inhibited by treatment with high dose CsA and potentiated by low dose CsA. In the CBA/H mice used, CsA treatment after immunization had no effect on autoantibody titres.

Acetylspiramycin and the immune system--II. Effects on lymphocyte proliferation, lymphokine production, delayed-type hypersensitivity and antibody production

The effects of the antibiotic acetylspiramycin (ASPM) on lymphocyte function were studied in vitro and in vivo. When added to lymphocyte cultures in vitro, ASPM inhibited splenic lymphocyte transformation induced by phytohemagglutinin (PHA), lipopolysaccharide (LPS) and antigen. It also depressed production by spleen cells of the lymphokine inducing procoagulant activity in mouse macrophages. Spleen cells from mice given ASPM orally showed enhanced responses to PHA, but normal responses to LPS. The capacity to produce lymphokine was increased early after oral ASPM and slightly decreased after prolonged administration. Oral ASPM had no effect on the production of antibodies and a very slight enhancing effect on the development of delayed-type hypersensitivity to sheep red blood cells.

Successful tumour immunotherapy: possible role of antibodies to anti-inflammatory factors produced by neoplasms

Phenol-saline tumour extracts, active in the immunotherapy of bovine ocular squamous cell carcinoma (BOSCC), were used to immunize mice. The immunized mice became resistant to the depression of delayed type hypersensitivity (DTH) reactions by products of BOSCC cells or cultured mouse or rat tumour cells. They also showed partial resistance to the growth of an unrelated tumour. Monoclonal antibodies to a type C retrovirus protein, p15E, also induced resistance to the depression of DTH by products of BOSCC and mouse tumours. It is suggested that successful immunotherapy of BOSCC is associated with the induction of resistance to anti-inflammatory or immunosuppressive tumour cell products, allowing the operation of host defences, and that these products share antigenic determinants with a retrovirus protein.