Ventilation rates in recently constructed U.S. school classrooms.

Low ventilation rates (VRs) in schools have been associated with absenteeism, poorer academic performance, and teacher dissatisfaction. We measured VRs in 37 recently constructed or renovated and mechanically ventilated U.S. schools, including LEED and EnergyStar-certified buildings, using CO2 and the steady-state, build-up, decay, and transient mass balance methods. The transient mass balance method better matched conditions (specifically, changes in occupancy) and minimized biases seen in the other methods. During the school day, air change rates (ACRs) averaged 2.0±1.3 hour-1 , and only 22% of classrooms met recommended minimum ventilation rates. HVAC systems were shut off at the school day close, and ACRs dropped to 0.21±0.19 hour-1 . VRs did not differ by building type, although cost-cutting and comfort measures resulted in low VRs and potentially impaired IAQ. VRs were lower in schools that used unit ventilators or radiant heating, in smaller schools and in larger classrooms. The steady-state, build-up, and decay methods had significant limitations and biases, showing the need to confirm that these methods are appropriate. Findings highlight the need to increase VRs and to ensure that energy saving and comfort measures do not compromise ventilation and IAQ.

Eye-tracking computer systems for inpatients with tetraplegia: findings from a feasibility study.

STUDY DESIGN: A longitudinal, prospective, self-controlled cohort study. OBJECTIVES: To determine (1) the preliminary benefits of using eye-tracking computer systems (ETCSs) among inpatients with tetraplegia and (2) the feasibility of carrying out a well-powered randomized controlled trial. SETTING: Specialist Spinal Cord Injuries Centre, United Kingdom; 6 months during 2013-2014. METHODS: Individuals with tetraplegia who were admitted to the center and enrolled in this study were trained and allowed to use the ETCS (Tobii Eyegaze C15 System) twice a week for a duration of 10 weeks. Standardized training modules were developed and offered to all study participants. Study feasibility indicators as well as the Appraisals of Disability: Primary and Secondary Scale, Hospital Anxiety and Depression Scale and the Assistive Technology Device Predisposition Assessment questionnaire scores were taken before and after study enrollment. RESULTS: A total of 31 inpatients with tetraplegia were screened. Although 14 patients (45%) met the study eligibility criteria, 6 patients (19%) consented to be enrolled in the study. Three participants did not complete the planned training schedule because of medical, technical and logistic reasons. Although half of the participants agreed that the ETCS under study was easy to use, no substantial improvements were seen in terms of psychological outcomes, appraisals of disability or independence. CONCLUSIONS: The conduct of a controlled trial evaluating the benefits of using ETCSs among newly injured patients with tetraplegia comes with considerable feasibility challenges. Until substantial technical improvements of ETCSs have been implemented, future research should initially focus on those individuals with tetraplegia who are living in the community and who have expressed a need to enhance their computer access and communication skills.

Allergic contact dermatitis due to thiuram exposure from a fungicide.

A 49-year-old man developed a widespread eczematous eruption following contact with plants sprayed with a fungicide. Patch testing revealed a strong reaction to thiuram mix and several of the individual thiuram mix constituents. The fungicide contained tetramethylthiuram disulphide, a thiuram chemical. Thiurams are widely recognized as a cause of rubber-glove allergy; however, they are also used extensively in fungicides.

A novel gene, NSD1, is fused to NUP98 in the t(5;11)(q35;p15.5) in de novo childhood acute myeloid leukemia.

The recurrent translocation t(5;11)(q35;p15.5) associated with a 5q deletion, del(5q), has been reported in childhood acute myeloid leukemia (AML). We report the cloning of the translocation breakpoints in de novo childhood AML harboring a cryptic t(5;11)(q35;p15.5). Fluorescence in situ hybridization (FISH) analysis demonstrated that the nucleoporin gene (NUP98) at 11p15.5 was disrupted by this translocation. By using 3'--rapid amplification of complementary DNA ends (3'-RACE) polymerase chain reaction, we identified a chimeric messenger RNA that results in the in-frame fusion of NUP98 to a novel gene, NSD1. The NSD1 gene has 2596 amino acid residues and a 85% homology to the murine Nsd1 with the domain structure being conserved. The NSD1 gene was localized to 5q35 by FISH and is widely expressed. The reciprocal transcript, NSD1-NUP98, was also detected by reverse transcriptase--polymerase chain reaction. This is the first report in which the novel gene NSD1 has been implicated in human malignancy. (Blood. 2001;98:1264-1267)

Telomere length shortening in chronic myelogenous leukemia is associated with reduced time to accelerated phase.

Telomere shortening is associated with disease evolution in chronic myelogenous leukemia (CML). We have examined the relationship between diagnostic telomere length and outcome in 59 patients with CML who entered into the MRC CMLIII Trial by Southern blot hybridization using the (TTAGGG)(4) probe. Age-adjusted telomere repeat array (TRA) reduction was found to significantly correlate with time from diagnosis to acceleration, such that patients with a larger TRA reduction entered the accelerated phase more rapidly (r = -0.50; P =.008). Cox-regression analysis for this group was suggestive of a relationship between a greater TRA-reduction and a shorter time to acceleration (P =.054). Age-adjusted TRA reduction did not significantly affect either the time to blast crisis or overall survival. Our results show that telomere shortening observed at the time of diagnosis in CML significantly influences the time to progress to the accelerated phase. The measurement of diagnostic TRA may prove to be clinically important in the selection of patients at high risk of disease transformation in CML.

Transcription mapping of the 5q- syndrome critical region: cloning of two novel genes and sequencing, expression, and mapping of a further six novel cDNAs.

The 5q- syndrome is a myelodysplastic syndrome with the 5q deletion ¿del(5q) as the sole karyotypic abnormality. We are using the expressed sequence tag (EST) resource as our primary approach to identifying novel candidate genes for the 5q- syndrome. Seventeen ESTs were identified from the Human Gene Map at the National Center for Biotechnology Information that had no significant homology to any known genes and were assigned between DNA markers D5S413 and D5S487, flanking the critical region of the 5q- syndrome at 5q31-q32. Eleven of the 17 cDNAs from which the ESTs were derived (65%) were shown to map to the critical region of the 5q- syndrome by gene dosage analysis and were then sublocalized by PCR screening to a YAC contig encompassing the critical region. Eight of the 11 cDNA clones, upon full sequencing, had no significant homology to any known genes. Each of the 8 cDNA clones was shown to be expressed in human bone marrow. The complete coding sequence was obtained for 2 of the novel genes, termed C5orf3 and C5orf4. The 2.6-kb transcript of C5orf3 encodes a putative 505-amino-acid protein and contains an ATP/GTP-binding site motif A (P loop), suggesting that this novel gene encodes an ATP- or a GTP-binding protein. The novel gene C5orf4 has a transcript of 3.1 kb, encoding a putative 144-amino-acid protein. We describe the cloning of 2 novel human genes and the sequencing, expression patterns, and mapping to the critical region of the 5q- syndrome of a further 6 novel cDNA clones. Genomic localization and expression patterns would suggest that the 8 novel cDNAs described in this report represent potential candidate genes for the 5q- syndrome.

Telomere length shortening is associated with disease evolution in chronic myelogenous leukemia.

We studied telomere length in the peripheral blood leukocyte samples of a large group of patients with chronic myelogenous leukemia (CML) by Southern blot hybridization using the (TTAGGG)4 probe. The average telomere length expressed as the peak telomere repeat array (TRA) of the peripheral blood samples obtained from a group of 34 healthy age-matched controls ranged between 7.6 and 10.0 kb and the mean peak TRA was 8.7 kb. Forty-one patients in the chronic phase of CML were studied; 32/41 (78%) showed telomere reduction (<7.6 kb) relative to age-matched controls and the mean peak TRA was 6.4 kb (range 4.0-10.6 kb). Serial samples were analysed from 12 patients at both chronic phase and during disease progression. The leukocyte DNA of all 12 patients in accelerated phase and/or blast crisis showed telomere reduction relative to age-matched controls and the mean peak TRA was 4.1 kb (range 3.0-5.4 kb). The peak TRA in the accelerated or blast phase was reduced compared with the corresponding paired sample in the chronic phase in all cases studied. These data show that a marked reduction in telomere length is associated with disease progression in CML.

Distal Interphalangeal Joint Arthrodesis Using Intramedullary and Interosseous Fixation.

Multiple fixation techniques have been developed for distal interphalangeal (DIP) joint arthrodesis. Delayed and nonunion rates varying from 0% to 20% have been reported. The senior author has refined a technique for DIP joint arthrodesis by using an intramedullary Kirschner wire and an interosseous wire for fusion of the DIP joint and interphalangeal (IP) joint of the thumb. In 24 joint arthrodeses in 19 patients, the nonunion rate was 4%, and the minor complication rate was 12%. The advantages of this technique include the absence of protruding hardware that would necessitate removal; consistency in achieving osteosynthesis, with a low nonunion rate; and technical simplicity.

Molten metal burns: further evidence of industrial foundries' failure to comply with Occupational Safety and Health Administration regulations.

The purpose of this report is to describe another case of a molten metal burn to the foot of a foundry worker. The foundry in which he worked failed to comply with Occupational Safety and Health Administration regulations with regard to protective apparel. This injury could have been prevented with annual, unscheduled inspections by the Occupational Safety and Health Administration and with enforcement of additional regulations regarding protective apparel.

Biomechanical performance of cutting edge surgical needles.

The purpose of this study was to compare the biomechanical performance of cutting edge needles made of S45500 stainless steel alloy to Surgalloy stainless steel. The new high-nickel stainless steel alloy, Surgalloy, has superior performance characteristics over that of the other high-nickel stainless steel alloy, S45500. The Surgalloy needle is produced from a stronger stainless steel alloy than the S45500 needle. The Surgalloy needle has considerably greater resistance to bending than the needle produced from S45500 alloy. In addition, Surgalloy stainless steel has almost a twofold greater resistance to fracture than the S45500 stainless steel alloy.

Metacarpophalangeal joint dislocation: indications for open surgical reduction.

In complex dislocations of the metacarpophalangeal joint, the volar plate is separated from the proximal phalanx and the metacarpal head is entrapped within surrounding tissue structures. These complex dislocations must be managed by open surgical reduction to reduce the dislocation and realign the volar plate. A 58-year-old male presented to the emergency department with a complex dislocation of the metacarpophalangeal joint of the left little finger, which was successfully treated by open reduction in the operating room. The indications for open reduction of metacarpophalangeal joint dislocations are reviewed.

Technical considerations in knot construction. Part II. Interrupted dermal suture closure.

The purpose of this study was to identify the optimal knot construction for interrupted dermal sutures. A synthetic braided absorbable suture, sizes 3-0 and 5-0, was selected for this evaluation. With reproducible mechanical performance tests, we determined that the construction of secure knots without ears required one additional throw as compared with secure knots with 3-mm ears. The direction of applied tension did not alter knot security, with the exception of granny knots, which required an extra throw when tension was applied parallel to the suture loop. Because interrupted dermal knot construction is accomplished without knot ears and with an applied tension parallel to the wound, one additional throw must be added to the knot to ensure knot security.

Surgical glove lubricants: from toxicity to opportunity.

In most emergency departments, surgical gloves are coated with surface powders that act as lubricants to facilitate donning. Cornstarch powder is an absorbable powder employed as a donning agent on most powdered gloves. Talcum powder, a nonabsorbable powder, is used as a mold release agent in glove manufacture and is still commonly found on the surfaces of modern surgical gloves. These powders are foreign bodies that elicit inflammatory responses, leading to a wide number of symptoms and complications. The best method of preventing clinical complications from glove powder is to use powder-free gloves.

A new computerized control unit for small bone surgical instruments.

The SmartDrive console represents an important advance in small bone surgery because it monitors and coordinates the operation of its handpieces. The SmartDrive console has the following unique features: 1) a handpiece recognition system; 2) an instrument speed display; 3) a handpiece display and monitoring system; 4) a torque instrument control system; 5) a temperature monitoring system; 6) and an irrigation system. Mechanical performance studies have been undertaken that have validated the accuracy of the monitoring systems of the consoles. The consoles provided reliable recordings of the rotational speeds of their hi-speed drills. The MicroAire console automatically shuts off its power as the temperature increased to 110 degrees F (43 degrees C). In contrast, the Stryker Command 2 console has a limited monitoring system that can not alter the operation of the handpieces.

Peritoneal healing with adhesion formation: current comment.

Intra-abdominal adhesions are fibrotic structures, which lie in the form of a string or attachment between the abdominal organs and connect these together. They are responsible for serious clinical complications that include intestinal obstruction, infertility, and pelvic pain. During the last century, surgeons' comprehensive understanding of the biology of peritoneal healing and wound repair has allowed them to identify a variety of new therapeutic techniques that limit the development of adhesion formation. New drugs, dextran 70 and poloxamer 407, have been developed to prevent adhesion formation. In addition, three new biomaterials (oxidized regenerated cellulose, hyaluronate membrane, and polytetrafluoroethylene) are synthetic barriers being used to prevent adhesions.

Biomechanical performance of a braided absorbable suture.

Lactomer and Polyglactin 910 sutures are both made of copolymers of lactide and glycolide. Biomechanical performance tests demonstrated superior handling characteristics of the Lactomer sutures. Using sutures comparable in size and knot construction, the Lactomer sutures exhibited knot holding force superior to the Polyglactin 910. Moreover, the low knot rundown forces encountered by the Lactomer sutures facilitated construction of secure knots that failed by breakage rather than by slippage.

Evolution of hydrogel polymers as contact lenses, surface coatings, dressings, and drug delivery systems.

Hydrogel polymers are hydrophilic resins that display excellent biocompatibility, which has allowed their application in diverse fields of surgery and medicine. The original hydrogel polymer, a copolymer of 2-hydroxyethyl methacrylate and ethylene dimethacrylate, was developed by Wichterle and Lim in 1954. The development of the first soft hydrogel contact lenses by Wichterle in 1961 represented the first successful clinical application of hydrogel polymers and remains one of the most important uses of hydrogels today. The biocompatibility of hydrogel polymers may be adapted to diverse tissue types by small variations in the makeup of the polymer, including varying the type and amount of monomers and differing the amounts and characteristics of the cross-linking agents used to create the polymer chains. Hydrogels have been successfully developed for use as coatings, soft contact lenses, wound dressings, and drug delivery systems.

Characterization of GABAergic neurons in hippocampal cell cultures.

The morphological characteristics of GABAergic neurons and the distribution of GABAergic synaptic terminals were examined in cultures of hippocampal neurons from 4-35 days in vitro. Neurons expressing GABA immunoreactivity represented about 6% of the total number of cultured neurons at all time points. Although the morphological characteristics of GABAergic cells suggested a heterogeneous population, GABAergic cells as a class were notably different from the non-GABAergic, presumably pyramidal cells. Most GABAergic cells had more fusiform or polygonal shaped somata, non-spiny and less tapering dendrites and appeared more phase-dense than nonGABAergic cells. Quantitative analysis revealed that GABAergic cells had fewer primary dendrites, more elongated dendritic arbors, and longer dendritic segments than non-GABAergic neurons-characteristics that are similar to GABAergic cells in situ. Double immunostaining revealed that GAD65-positive varicosities were also immunopositive for synapsin I, suggesting that GAD65-positive varicosities that contacted somata and dendrites represented presynaptic specializations. Confocal microscopy revealed the proportion of the synaptic specializations on the cell soma that were GAD65-positive was greater than on the dendrites, suggesting that somata and dendrites differ in their ability to induce the formation of presynaptic specializations by GABAergic axons. These data indicate that the GABAergic cells that develop in culture exhibit distinctive morphological characteristics and participate in different synaptic interactions that nonGABA cells. Thus many of the features that distinguish GABAergic neurons in culture are reminiscent of the characteristics that distinguish GABAergic neurons in situ.

The migration of Langerhans' cells into and out of lymph nodes draining normal, carcinogen and antigen-treated sheep skin.

Epidermal Langerhans' cell (LC) migration to the regional lymph node and beyond into central lymph was examined in sheep following topical application of the complete chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) or the contact sensitizing antigen 2,4,6-trinitrochlorobenzene (TNCB). This was facilitated by cannulating previously constructed pseudoafferent lymphatic vessels draining the skin treated with these agents or alternatively, the efferent lymphatic vessel of the regional lymph node. Application of DMBA resulted in a biphasic increase in LC migration. There was an initial increase in LC migration at 25 h with the maximum response (3.6 x 10(7) LC/h) occurring approximately 5 days after DMBA treatment. In contrast, the contact sensitizing antigen TNCB caused enhanced LC migration within minutes of the application of antigen (3.3 x 10(6) LC/h) and peak migration at 8-12 h. Examination of efferent lymph cells from the regional lymph node after DMBA treatment showed uncharacteristically large numbers of LC traversing the lymph node. These LC migration patterns suggest different mechanisms may trigger the migration of LC from skin after the application of DMBA to those associated with the normal processes of antigen presentation.

Investigations into the fat pads of the sole of the foot: anatomy and histology.

Anatomical, histological, and histochemical studies were performed on normal and abnormal fat pads of the sole of cadaver feet. The fat pads were found to contain a significant nerve and blood supply separate from that to the surrounding musculature and skin. Pacinian corpuscles and free nerve endings within the fat were identified. Histological analysis indicated a meshwork of fibroelastic septae arranged in a closed-cell configuration. The mechanical consequences of this organization are discussed in the context of the weightbearing role of the fat pads of the feet. Alterations seen in dysvascular or senescent feet are consistent with the hypothesis that the septal anatomy of the fat pads is central to their cushioning function.