Survey of intensive care physicians on the recognition and management of intra-abdominal hypertension and abdominal compartment syndrome.

OBJECTIVE: To assess current understanding and clinical management of intra-abdominal hypertension and abdominal compartment syndrome among critical care physicians. DESIGN: A ten-question, written survey. SETTING: University health sciences center. SUBJECTS: Physician members of the Society of Critical Care Medicine (SCCM). INTERVENTIONS: The survey was sent to 4,538 SCCM members with a response rate of 35.7% (1622). MEASUREMENTS AND MAIN RESULTS: Primary training, intensive care unit type, and methods for management of abdominal compartment syndrome were assessed. Surgically trained intensivists managed the highest number of abdominal compartment syndrome cases (47% managed 4-10 cases, 16% managed >10 cases). No cases were seen by 25% of medically trained and pediatric trained intensivists. Respondents agreed that bladder pressures and clinical variables were needed to diagnose abdominal compartment syndrome (70%) vs. bladder pressure (7%) or clinical variables (20%) alone. Two percent of surgical intensivists were unaware of a bladder pressure measurement procedure compared with 24% (p < .0001) of pediatric and 23% (p < .0001) of medical intensivists. Forty-two percent of respondents believed bladder pressures of 20-27 mm Hg may cause physiologic compromise. However, 25-27% of pediatric, medicine, or anesthesia trained intensivists believed that compromise occurs between 12 and 19 mm Hg compared with 18% of surgeons. No respondent believed that physiologic compromise occurred at <8 mm Hg. Thirty-eight percent of pediatric intensivists believed that physiologic compromise was patient dependent vs. 7-17% from other specialties (p < .0001; all comparisons). In managing intra-abdominal hypertension, 33% of pediatric intensivists and 19.6% of medical intensivists would never use decompression laparotomy to treat abdominal compartment syndrome compared with 3.6% of intensivists with surgical training (p < .0001; both comparisons). CONCLUSIONS: Significant variation across medical training exists in the management of intra-abdominal hypertension and abdominal compartment syndrome. A significant percentage of intensivists may be unaware of current approaches to abdominal compartment syndrome management including monitoring bladder pressures and decompression laparotomy. Future research and education are necessary to establish clear diagnostic criteria and standards for treatment of this relatively common life-threatening disease process.

Thermal inertia associated with ultrapulse technology in phacoemulsification.

PURPOSE: To determine whether very short pulses of ultrasound (5 to 6 milliseconds) have less heat propagation in biological tissue (thermal inertia) than traditional pulses (50 milliseconds). SETTING: Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah. METHODS: Thermal testing was done in balanced salt solution (BSS) and in eye-bank eyes. In the same fresh human eye-bank eye, net temperature increase after 20 seconds of ultrasound (50 milliseconds on and 50 milliseconds off) was compared with the increase after 6 milliseconds on and 12 milliseconds off with the same phacoemulsification unit. The same experiment and setting was run in BSS and the eye-bank ratios compared with the BSS ratios. Twenty runs were done at each power setting in BSS and 22 in the eye-bank eye. RESULTS: There was 10.9% less heat generated with 6-millisecond pulses of ultrasound in limbal tissue than in BSS compared with 50-millisecond pulses of ultrasound (P = .0002). CONCLUSION: Very short pulses of ultrasound (5 to 6 milliseconds) propagated less thermal energy in limbal tissue than in BSS compared with 50-millisecond ultrasound pulses.

Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

PURPOSE: To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. SETTING: University ophthalmology department. METHODS: The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. RESULTS: The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). CONCLUSION: Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

HIV Gag mimics the Tsg101-recruiting activity of the human Hrs protein.

The HIV-1 Gag protein recruits the cellular factor Tsg101 to facilitate the final stages of virus budding. A conserved P(S/T)AP tetrapeptide motif within Gag (the "late domain") binds directly to the NH2-terminal ubiquitin E2 variant (UEV) domain of Tsg101. In the cell, Tsg101 is required for biogenesis of vesicles that bud into the lumen of late endosomal compartments called multivesicular bodies (MVBs). However, the mechanism by which Tsg101 is recruited from the cytoplasm onto the endosomal membrane has not been known. Now, we report that Tsg101 binds the COOH-terminal region of the endosomal protein hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs; residues 222-777). This interaction is mediated, in part, by binding of the Tsg101 UEV domain to the Hrs 348PSAP351 motif. Importantly, Hrs222-777 can recruit Tsg101 and rescue the budding of virus-like Gag particles that are missing native late domains. These observations indicate that Hrs normally functions to recruit Tsg101 to the endosomal membrane. HIV-1 Gag apparently mimics this Hrs activity, and thereby usurps Tsg101 and other components of the MVB vesicle fission machinery to facilitate viral budding.

Structure and ubiquitin interactions of the conserved zinc finger domain of Npl4.

Ubiquitylated proteins are directed into a large number of different cellular pathways through interactions with effector proteins that contain conserved ubiquitin binding motifs. Here, we report the solution structure and ubiquitin binding properties of one such motif, the Npl4 zinc finger or RanBP2/Nup358 zinc finger (NZF) domain. Npl4 NZF forms a compact module composed of four antiparallel beta-strands linked by three ordered loops. A single zinc ion is coordinated by four conserved cysteines from the first and third loops, which form two rubredoxin knuckles. Npl4 NZF binds specifically, but weakly, to free ubiquitin using a conserved 13TF14 dipeptide to interact with the "Ile-44" surface of ubiquitin. Our studies reveal the structure of this versatile class of protein binding domains and provide a means for identifying the subset of NZF domains likely to bind ubiquitin.