Wilhelm A. Zuelzer

Skeletal muscle phosphatidylcholine fatty acids and insulin sensitivity in normal humans

The fatty acid composition of skeletal muscle membrane phospholipids (PL) is known to influence insulin responsiveness in humans. However, the contribution of the major PL of the outer (phosphatidylcholine, PC) and inner (phosphatidylethanolamine, PE) layers of the sarcolemma to insulin sensitivity is not known. Fatty acid composition of PC and PE from biopsies of vastus lateralis from 27 normal men and women were correlated with insulin sensitivity determined by the hyperinsulinemic euglycemic clamp technique at insulin infusion rates of 0.4, 1.0, and 10.0 mU . kg-1 . min-1. Significant variation in the half-maximal insulin concentration (ED50) was observed in the normal volunteers (range 24.0-146.0 microU/ml), which correlated directly with fasting plasma insulin (r = 0.75, P < 0.0001). ED50 was inversely correlated with the degree of membrane unsaturation (C20-C22 polyunsaturated fatty acids; r = 0. 58, P < 0.01) and directly correlated with fatty acid elongation (ratio of 16:0 to 18:0, r = 0.45, P < 0.05) in PC. However, no relationship between fatty acid composition and insulin sensitivity was observed in PE (NS). These studies suggest that the fatty acid composition of PC may be of particular importance in the relationship between fatty acids and insulin sensitivity in normal humans.The fatty acid composition of skeletal muscle membrane phospholipids (PL) is known to influence insulin responsiveness in humans. However, the contribution of the major PL of the outer (phosphatidylcholine, PC) and inner (phosphatidylethanolamine, PE) layers of the sarcolemma to insulin sensitivity is not known. Fatty acid composition of PC and PE from biopsies of vastus lateralis from 27 normal men and women were correlated with insulin sensitivity determined by the hyperinsulinemic euglycemic clamp technique at insulin infusion rates of 0.4, 1.0, and 10.0 mU ⋅ kg-1 ⋅ min-1. Significant variation in the half-maximal insulin concentration (ED50) was observed in the normal volunteers (range 24.0-146.0 μU/ml), which correlated directly with fasting plasma insulin ( r = 0.75, P < 0.0001). ED50 was inversely correlated with the degree of membrane unsaturation (C20-C22polyunsaturated fatty acids; r = 0.58, P < 0.01) and directly correlated with fatty acid elongation (ratio of 16:0 to 18:0, r = 0.45, P < 0.05) in PC. However, no relationship between fatty acid composition and insulin sensitivity was observed in PE (NS). These studies suggest that the fatty acid composition of PC may be of particular importance in the relationship between fatty acids and insulin sensitivity in normal humans.

Successful use of alcohol sensor technology to monitor and report hand hygiene compliance.

Nearly two million healthcare-associated infections are estimated to occur annually in the USA, accounting for nearly 100 000 deaths.1 Many of these infections are suspected to be due to poor compliance with hand hygiene and The Joint Commission has included improvement of compliance with hand hygiene in its National Patient Safety Goals since 2004, and has mandated that hospitals measure compliance rates. However, producing valid performance data remains a challenge.2

Changes in phsophatidylcholine fatty acid composition are associated with altered skeletal muscle insulin responsiveness in normal man

The fatty acid composition of skeletal muscle cell membrane phospholipids (PLs) is known to influence insulin responsiveness in man. We have recently shown that the fatty acid composition of phosphatidylcholine (PC), and not phosphatidylethanolamine (PE), from skeletal muscle membranes is of particular importance in this relationship. Efforts to alter the PL fatty acid composition in animal models have demonstrated induction of insulin resistance. However, it has been more difficult to determine if changes in insulin sensitivity are associated with changes in the skeletal muscle membrane fatty acid composition of PL in man. Using nicotinic acid (NA), an agent known to induce insulin resistance in man, 9 normal subjects were studied before and after treatment for 1 month. Skeletal muscle membrane fatty acid composition of PC and PE from biopsies of vastus lateralis was correlated with insulin responsiveness using a 3-step hyperinsulinemic-euglycemic clamp. Treatment with NA was associated with a 25% increase in the half-maximal insulin concentration ([ED50] 52.0 +/- 7.5 to 64.6 +/- 9.0 microU/mL, P < .05), consistent with decreased peripheral insulin sensitivity. Significant changes in the fatty acid composition of PC, but not PE, were also observed after NA administration. An increase in the percentage of 16:0 (21% +/- 0.3% to 21.7% +/- 0.4%, P < .05) and decreases in 18:0 (6.2% +/- 0.5% to 5.1% +/- 0.4%, P = .01), long-chain n-3 fatty acids (1.7% +/- 0.2% to 1.4% +/- 0.1%, P < .01), and total polyunsaturated fatty acids ([PUFAs] 8.7% +/- 0.8% to 8.0% +/- 0.8%, P < .05) are consistent with a decrease in fatty acid length and unsaturation in PC following NA administration. The change in ED50 was significantly correlated with the change in PUFAs (r = -.65, P < .05). These studies suggest that the induction of insulin resistance with NA is associated with changes in the fatty acid composition of PC in man.

Arthroscopic training using pig knee joints.

Arthroscopy can be a difficult technique for the resident and staff physician to master. Various models have been constructed to allow the training arthroscopist time to perfect the technique. Aside from cadaver knees, there has been only one report of a successful in vivo training model. Sectioned pig knee joints for teaching and practicing arthroscopy satisfy many of the points suggested by others: they are cost effective, easy to use, mount and store, provide a realistic approach, and have comparable structural anatomy to the human knee.

Avascular necrosis of the femoral head: Early MRI detection and radiological correlation

Magnetic Resonance Imaging (MRI) and conventional radiographs were compared in 49 hips with Avascular Necrosis (AVN). MRI detected AVN in 25% of the hips during the preradiological stage of the disease. Both MRI and conventional radiographs accurately detected AVN in the remaining 75% of hips. Correlation between the patterns observed with the two techniques reflected the underlying histopathologic events. The reactive interface between infarcted bone and viable bone could be identified on MRI as a low signal intensity (SI) band. On conventional radiographs the reactive interface appeared as a sclerotic band. The adjacent hyperemic zone was seen on MRI as a high SI band and as a lucent zone on the plain films. Variations of this pattern occurred as related to the extend and duration of AVN and to the individuals ability to mount a healing response. Minor degrees of collapse of the femoral head were better identified with plain radiographs but MRI demonstrated small areas of hyperintensity probably corresponding to early subchondral fractures.

Continued Non-Compliance with the American College of Surgeons Recommendations To Decrease Infectious Exposure in the Operating Room: Why?

BACKGROUND The American College of Surgeons (ACS) Statement on Sharps Safety recommends the use of double gloving (DG), hands-free zone (HFZ), and blunt-tip suture needles (BTSN) in the operating room to decrease needlestick injuries. Despite this endorsement, compliance is low. This survey determined the perceptions, attitudes, and barriers to compliance with these guidelines. METHODS A survey using a voluntary convenience sample of surgical staff members in which queries related to understanding of the ACS recommendations were posed. A total of 107 of the 324 surveys were completed and returned, for a response rate of 33%. Most respondents were residents (64%) or attending surgeons (29%). RESULTS Respondents were most familiar with recommendations for DG (58% of residents and 68% of attendings) and HFZ (61% for both groups) but less so for BTSN (48% of residents and 52% of attendings). More than 50% of the staff believed that DG decreased the risk of needlesticks, yet fewer than half used DG more than 75% of the time. Half believed that HFZ protected from sticks, yet fewer than 10% used it at least 75% of the time. Fewer than 50% believed that BTSN minimizes the risk of injury, with fewer than 10% of respondents using them at least 75% of the time. Reasons for non-compliance included decreased tactile sensation with DG, lack of training with HFZ, and lack of availability of BTSN. CONCLUSIONS To improve compliance with the ACS recommendations, institutions must improve awareness of the guidelines and the benefits associated with compliance and remove barriers to their incorporation into standard practice.

On the construction circuitry and properties of liquid metal strain gages

A quick and easy method by which reliable and accurate liquid metal strain gages (LMSG) can be manufactured for use in measuring large strains within biological tissues has been developed. The circuitry used to power the gages is also simple and allows gage voltages to be recorded without the need for instrumentation amplifiers. An added advantage is that the gage output indicates absolute gage length rather than change in gage length. Lastly, evaluation of these gages error sensitivity has shown them to be acceptable for measurement of strains of magnitudes occurring within many soft tissues.

The dorsal ganglion with anomalous muscles.

Either an anomalous extensor indicis proprius muscle or an extensor digitorum brevis manus may coexist with a dorsal wrist ganglion. To assure relief of symptoms, treatment must include division of the fourth dorsal extensor compartment in the case of the former muscle, and excision in the case of the latter.

Traumatic Pseudoaneurysm in a Wrestler

An 18-year-old man sought treatment for a pulsatile mass in the medial distal thigh four years after he had sustained blunt trauma during a wrestling match. Investigation, which included magnetic resonance imaging and arteriography, showed the mass to be a pseudoaneurysm, which should be considered in the differential diagnosis of masses resulting from direct, blunt trauma. At exploration, a pseudoaneurysmic thrombus in the superficial femoral artery was evacuated and the vessel was repaired with an interposition graft of reversed saphenous vein, followed by complete recovery of the patient.

pN collagen type III within tendon grafts used for anterior cruciate ligament reconstruction

This study measured the amount of immature collagen type III present in tendon rafts obtained from anterior cruciate ligament (ACL) reconstructions. These values were compared with those obtained from control grafts typically used for reconstruction — Achilles, patellar, and fascia lata — and also to the normal ACL. Analyses were performed using a commercially available radio‐immunoassay (RIA). The RIA made use of a rabbit polyclonal antibody specific to the amino terminus of procollagen type III. The specificity of the Ab was confirmed by a western blot. Fibril diameter of each of the above samples was measured by transmission electron microscopy (TEM). We thus were able to determine if there was a relationship between pN collagen III content and fibril diameter.