William M. Kuzon

A Histochemical Method for the Simultaneous Demonstration of Capillaries and Fiber Type in Skeletal Muscle

A modified ATPase method for the simultaneous demonstration of capillaries and fiber types in skeletal muscle is presented. Muscle biopsies were obtained from mice, hamsters, rats, cats, and dogs, quick frozen, and sectioned at 8 microns in a cryostat. The frozen slides were fixed in a neutral formalin solution at 4 C for 5 min, and then incubated at 37 C for 1 hr in a medium containing ATP, Pb2+, and Ca2+ in a tris-maleate buffer (pH 7.2). Dilute (NH4)2S was used as a developer. To test the reliability of the proposed method, serial sections of each biopsy were stained separately for capillaries (amylase-PAS method) and for fiber types by a standard myosin ATPase (m-ATPase) method. Fiber type percent and capillary parameters were determined for each biopsy. No difference in results was observed for parameters determined using the modified ATPase method compared to the standard capillary and fiber type staining methods. This modified technique is therefore suitable for the simultaneous demonstration of capillaries and fiber types in skeletal muscle.

Evaluations of aesthetic results in breast reconstruction: an analysis of reliability.

This study evaluated the reliability of three commonly used measures of aesthetic outcomes of breast surgery: a four-point ordinal scale of overall aesthetics, five four-point subscales, and a visual analogue scale. Fifty patients were randomly selected from women who underwent breast reconstruction surgery at University of Michigan hospitals between July 1989 and May 1993. Postoperative photographs of these patients were provided to three plastic surgeons, who were asked to rate the photographs using the three methods. The same process was repeated 4 weeks later. Intrarater and interrater reliability ranged from poor to good for the three methods, with the subscales showing the highest reliability. The lowest reliability occurred for those scales with the least-explicit rating criteria. Without explicit criteria, raters must develop and use their own criteria, which are likely to differ for each rater. Separating the various components of the aesthetic results of breast surgery into different subscales helps make the rating criteria more explicit. Scales with demonstrated reliability are critical for ensuring comparability of results across studies.

An isolated skeletal muscle model suitable for acute ischemia studies

A modified isolated canine gracilis model of acute complete muscle ischemia was developed and then tested metabolically and histologically in 25 animals to assess its validity. In each dog, both gracili were isolated on their major vascular pedicles. One muscle underwent ischemia and reperfusion by placing and removing microvascular clips on the artery and vein. The other gracilis muscle was used as a control. Total muscle blood flow measurements, blood samples, and muscle biopsies were taken every other hour for up to 11 hr after preparation. The fiber-type profile of the gracilis was determined bilaterally using a myosin ATPase stain (n = 10). The results verified these hypotheses: after surgical preparation, the right and left muscles in the same dog are equivalent metabolically, after a 2-hr stabilization period, gracilis blood flow, oxygen and glucose uptake, lactate release, and tissue glycogen, lactate, phosphocreatine, and ATP levels remain within normal limits and unchanged for the next 9 hr, the surgical isolation of the gracilis muscle on a single vascular pedicle does not result in significant metabolic changes, in this model, a 2-hr ischemia is reversible, but a 7-hr ischemia results in irreversible ischemic injury. As well, fiber-type profile, muscle blood flow, and metabolic parameters can very significantly among animals supporting the necessity of a contralateral control. Therefore, this modified gracilis muscle model with its contralateral muscle as a control is suitable for acute skeletal muscle ischemia experiments of at least 9-hr duration.

Isometric contractile function recovery following tourniquet ischemia

The purpose of this study was to document the recovery of isometric contractile function following tourniquet ischemia. Male Wistar rats (N = 27) were subjected to unilateral hindlimb tourniquet ischemia of 0 hr (control, N = 6), 1 hr (N = 5), 2 hr (N = 5), 3 hr (N = 5) and 4 hr (N = 3). Following a 2-week recovery period, isometric force measurements were made from both gastrocnemii of each rat with the contralateral limb acting as the control side. Each muscle was analyzed for maximal twitch (Pt, N/g), maximal rate of rise of twitch tension (DP/dt, N/sec), time to peak tension (TPT, msec), half relaxation time (RT 1/2, msec), maximal tetanus (P0, N/g, at 100 Hz), and fatigue (Burke Fatigue Protocol). Pt, P0, and DP/dt were significantly different from control values (P less than 0.05) for all hours of tourniquet ischemia. A strong negative correlation (P less than 0.001) was found for twitch (R = -0.84), tetanus (R = -0.78), and maximal rate of force development (R = -0.83) with respect to increasing hours of ischemia. The recovery of isometric twitch and tetanic function following tourniquet ischemia is inversely related to the ischemic interval. This study quantified the relationship between muscle ischemia and recovery of function following a 2-week interval and stresses the functional physiological changes which occur in skeletal muscle following tourniquet ischemia.

Functioning free muscle transplantation: making it work? What is known?

Since the early 1970s, the feasibility of transferring a muscle and having it survive and eventually function has been demonstrated both in research laboratories and clinically. Over a decade later, the factors influencing success are better understood. There have been significant contributions in concepts of muscle anatomy, muscle physiology, muscle reinnervation, and muscles response to ischemia. Ischemia time, within reason, does not appear to be as influential as first thought. The potential for demonstrating the efficacy of postoperative exercise is but one of the areas that could benefit from further research endeavors.

The effect of hypothermia on changes in isometric contractile function in skeletal muscle after tourniquet ischemia

The effect of hypothermia on changes in contractile function of skeletal muscle observed after an episode of tourniquet ischemia has been investigated. Male Wistar rats were subjected to 2 hours of unilateral hypothermic (n = 33) or normothermic (n = 39) pneumatic tourniquet ischemia of a hind limb. Isometric contractile function was measured bilaterally from the gastrocnemius muscles after 1, 7, 14, 28, or 42 days of recovery. Compared to muscle subjected to normothermic ischemia, muscle that underwent hypothermic ischemia demonstrated more twitch tension at 1 day postischemia, higher maximum tetanic tension at all time periods, including 6 weeks after ischemia, and greater muscle weight at 6 weeks. Rat gastrocnemius muscle function is much better 1 day to 6 weeks after 2 hours of hypothermic ischemia than after 2 hours of normothermic ischemia. The results thus document the benefit of hypothermia during tourniquet ischemia in preventing or minimizing the changes in isometric contractile function observed after normothermic ischemia.

The effect of intraoperative ischemia on the recovery of contractile function after free muscle transfer

Isometric contractile function was studied after recovery in free, vascularized muscle transfer subjected to graded periods of intraoperative ischemia. Fifteen dogs had orthotopic replantation of their left gracilis muscles, with intraoperative ischemia times grouped as 0 (n = 3), 1 to 2 (n = 3), 2 to 3 (n = 4), or 3 to 4 (n = 5) hours. After recovery (mean 61.8 weeks), isometric twitch and tetanic tension and fatigue measurements were made in the replants and in the contralateral, control gracilis. On the average, replants were found to produce significantly less twitch (0.32 +/- 0.13 versus 0.49 +/- 0.24 N/g) and 75 Hz tetanic tension (2.2 +/- 0.9 versus 3.4 +/- 0.5 N/g) than controls. However, in several individual replants, 100% of control maximal tetanic tension was observed. Intraoperative ischemia time of up to 4 hours was not correlated with functional return. It is concluded that (1) full recovery is possible after free muscle transfer; (2) intraoperative ischemia, if less than 4 hours long, is not the primary determinant of functional recovery; and (3) factors besides intraoperative ischemia must be operative in producing the variability in recovery seen in this setting.

Mycobacterium avium infection in a patient with acquired immunodeficiency syndrome and a solid silicone buttock implant

A 31-year-old female patient with both acquired immunodeficiency syndrome and a solid silicone buttock implant presented with fever. Using ultrasound-guided aspiration of the periprosthetic space, a diagnosis of Mycobacterium avium complex infection involving the implant was made. The implant was surgically removed and the patient had a resolution of her fevers while treated with ethambutol, rifabutin, ciprofloxacin, and clarithromycin.

An apparatus for the calibration of electromagnetic flowprobes on small veins in situ

Electromagnetic flowprobe calibration must be done under controlled conditions similar to those encountered experimentally. This in situ calibration apparatus is simple in design, inexpensive, and provides pressure and flow conditions analogous to those found in small veins in vivo.

Intramuscular comparison of myosin isozymes and light chains in rat extensor digitorum longus muscle

Complete muscle cross sections were obtained from the proximal and distal third regions of ten rat extensor digitorum longus muscles. Electrophoretic methods were then used to quantify the various myosin isozymes and light chains in each muscle specimen. The results demonstrated that the relative distribution of the various myosin isozyme and light chain variables do not vary significantly between the two sampling regions.