Analyse biochimique d´un pic insolite d´allure monoclonale en électrophorèse des protéines urinaires: à propos d´un cas

L´électrophorèse des protéines urinaires est souvent nécessaire au diagnostic et au suivi de certaines pathologies urologiques ou rénales, et des hémopathies lymphoïdes. Nous rapportons le cas d´un profil atypique d´électrophorèse des protéines urinaires sur capillaire et en gel d´agarose. Il s´agit d´un pic de nature inconnue d´allure monoclonale migrant au niveau des gammaglobulines. La littérature et les dosages effectués prouvent qu´il s´agissait de la myoglobine. En effet, la myoglobine de 17,5 kDa est librement filtré par le glomérule, et normalement réabsorbé au niveau tubulaire. En cas de dépassement de sa capacité de réabsorption, sa présence entraine une protéinurie de surcharge. Cette myoglobinurie nous a permis de mettre en évidence une rhabdomyolyse aigüe chez notre patient. Ainsi, l´analyse des pics inconnus comme dans ce cas, renseigne sur des symptomatologies, mais aussi des pathologies sous-jacentes, qui peuvent avoir un intérêt clinique.

Exercise-induced rhabdomyolysis

Exercise-induced rhabdomyolysis, or exertional rhabdomyolysis (ER), is a clinical entity typically considered when someone presents with muscle stiffness, swelling, and pain out of proportion to the expected fatigue post exercise. The diagnosis is confirmed by myoglobinuria, and an elevated serum Creatinine Phosphokinase (CPK) level, usually 10 times the normal range. However, an elevation in CPK is seen in most forms of strenuous exercise, up to 20 times the upper normal range. Therefore, there is no definitive pathologic CPK cut-off. Fortunately the dreaded complication of acute renal failure is rare compared to other forms rhabdomyolysis. We review the risks, diagnosis, clinical course and treatment for exercise- induced rhabdomyolysis.

Episodes of exercise-induced dark urine and myalgia in LGMD 2I

BACKGROUND

Mutations in the fukutin-related protein gene FKRP (MIM *606596) cause a form of congenital muscular dystrophy (MDC1C) and also limb girdle muscular dystrophy type 2I (LGMD2I). Exercise-induced myoglobinuria, frequently occurring in metabolic myopathies, has been described in Becker muscular dystrophy and in a few cases of LGMD.

OBJECTIVES

To describe that episodes with myoglobinuria, often associated with exercise-induced myalgia, may be common and a presenting symptom in patients with LGMD2I.

METHODS

Data on episodes of suspected myoglobinuria and myalgia were collected from the patient records on 14 patients with a diagnosis of LGMDI.

RESULTS

Five LGMD2I patients reported recurrent episodes of dark urine and myalgia after exercise, and in three of them, this was the only symptom for several years.

CONCLUSIONS

We conclude that episodes compatible with exercise-induced myoglobinuria may be frequent in LGMD2I.

[Treatment for crush syndrome of extremities with antioxidants]

OBJECTIVE

To study the clinical therapeutic effect of antioxidants assistant treatment of extremities crush syndrome (CS)in order to find new therapy.

METHODS

Twenty-one male patients (aged from 24 to 48 years, mean 36 years) were treated with the next antioxidants in early stage: (1) 20% Mannitol 250 ml intravenous drip in 30 minutes (one time per 6 to 8 h). (2) Sodium aescinate 20 mg, Salvia Miltiorrhiza 20 ml were dissolved respectively in isotonic saline or 5% glucose 200 ml and dripped by intravenous drip (50 to 60 drips per minute). The drugs were used for 5 to 7 days (one time per day). Basifying urine, keeping the nagative liquid banlance and electrolyte banlance, preventing infection and hold out treatment were done. When the pressure of muscular osteofascial compartment was more than 30 mmHg, deep fasia was cut to decompress timely and the above-mentioned drugs were continuously applied for patients.

RESULTS

Myoglobin urine of 21 cases died out after 2 to 3 days, of them, 13 cases were performed to decompress. After open decompression, 2 cases suffered from amputation because of long time of ischemia, 2 cases took place slight dysfunction of lower limbs, one hand had ischemia muscular contracture in 1 case and one foot down-vertical in 1 case. After followed-up of 8 months to 1 year, according to the function standard, the result were excellent in 8 cases, good in 7 cases, fair in 2 cases, poor in 4 cases. The excellent and good rate was about 71.4% (15/21).

CONCLUSION

After extremities crushed for long time, application of antioxidents as early as possible can decrease significantly the incidence and invalidity rate of CS.

Muscle cell injury, haemolysis and dark urine in children with falciparum malaria in Papua New Guinea

During a prospective study of red cell variants and severe malaria in children, a surprising observation was the occurrence of dark urine. Children were grouped according to urine findings: 22 had dark urine that contained a haem protein (Group I), 93 had urine of normal colour that contained a haem protein (Group II) and 236 had normal urine (Group III). To investigate the cause of dark urine, haemolysis and muscle cell injury were assessed. Intravascular haemolysis was greater in Group I than in Groups II and III. However, anaemia was more severe in Group III and is likely to have resulted mainly from extravascular haemolysis. Median plasma myoglobin concentrations were greater in Groups I and II than Group III (P = 0.00060). Plasma myoglobin was greater in children with cerebral malaria, hyperlactataemia and those who died but was not associated with acidosis. Urine myoglobin was greater in Group I than Groups II and III (P = 0.00054). It is likely that both haemoglobin and myoglobin contributed to dark urine. The association between muscle cell injury and coma suggests sequestration of parasitized red cells as a common underlying pathology. In malaria, hyperlactataemia may result directly from breakdown of muscle protein as well as tissue hypoxia.

Factors affecting urinary myoglobin stability in vitro

Urine myoglobin concentrations are measured clinically to assess rhabdomyolysis and the related risk of renal damage. We studied urine myoglobin concentrations in vitro to explore the factors affecting stability. Myoglobin was very unstable in urine specimens, especially below pH 6.5, and its immunoreactivity deteriorated rapidly with increasing temperatures. The deterioration rate was influenced greatly by urine myoglobin concentration, suggesting rate-limiting kinetics. Myoglobin in acidic phosphate-buffered saline was significantly more stable than in acidic urine, indicating that urinary factors in addition to pH are involved in myoglobin instability. These unidentified urinary factors had a molecular weight of less than 10 kd. Our results provide additional insight into the mechanism involved in the instability of the urine myoglobin concentration. Understanding the stability of myoglobin in the preanalytic in vitro phase and its potential in vivo instability is essential in assuring the reliability and clinical usefulness of urine myoglobin measurements.

Diver with decompression injury, elevation of serum transaminase levels, and rhabdomyolysis

A 43-year-old female recreational scuba diver presented to the emergency department 1 hour after a rapid, uncontrolled ascent. Her presentation included progressing confusion, slow and slurred speech, and complaints of headache and hypesthesia over her forearms and anterior thighs bilaterally. Differential diagnosis included arterial gas embolism and decompression sickness. She underwent recompression therapy with US Navy Table 6 within 120 minutes of her ascent. After recompression therapy, the patient had signs and symptoms consistent with severe rhabdomyolysis, including creatine kinase levels of 36,000 U/L and myoglobinuria.

Post-mortem urinary myoglobin levels with reference to the causes of death

To evaluate pathophysiological significance of post-mortem urinary myoglobin levels in determining the cause of death, we investigated 210 forensic autopsy cases, partially in comparison with serum levels. Post-mortem serum myoglobin levels were extraordinary high in most cases possibly due to post-mortem change. Urinary myoglobin levels did not correlate with the serum levels, showing possible post-mortem elevation in cases of a prolonged post-mortem period over 48h. A high (>1000 ng/ml), moderate (100-1000 ng/ml), slight (50-100 ng/ml) and not significant (<50 ng/ml) elevation of urinary myoglobin were observed in 26, 43, 31 and 110 cases, respectively. Half the highly elevated cases were those with a survival time over 24h. In cases of minor muscle injury such as head trauma, elevation of urinary myoglobin level was closely related to longer survival. In acute/subacute deaths with a post-mortem interval within 48h, a significant difference was observed in relation to the blood carboxyhemoglobin (COHb) levels of fire victims: myoglobinuria over 100 ng/ml was more frequently and markedly observed in cases with COHb below 60% than over 60%, suggesting muscle damage in fatal burns. Similar elevation was observed in heat stroke victims, and also in some cases of acute and subacute death from polytrauma, asphyxiation, drowning, electricity and spontaneous cerebral bleeding, but not in myocardial infarction. Thus, it was suggested that high post-mortem urinary myoglobin levels in acute and subacute death cases may be a possible indicator of antemortem massive skeletal muscle damage as well as exertional muscle hyperactivity or convulsive disorders associated with hypoxia.

Heroin overdose and myoglobinuric acute renal failure

BACKGROUND

Heroin abuse is an increasing problem in Australia. In our hospitals we have noted an apparent increase in drug-related admissions. In this study we aimed to examine the incidence of renal failure due to heroin-related rhabdomyolysis and to determine any predisposing factors to the requirement for dialysis in these patients.

PATIENTS AND METHODS

We identified a group of 27 patients who developed renal failure after recent intravenous heroin use. There was a significant rise in the incidence during 1997-1998 compared with the previous seven years (p < 0.05).

RESULTS

Rhabdomyolysis was the likely cause of renal failure in all cases. Eight patients required dialysis for an average of 14 days (range 3-26). Patients who required dialysis had a higher admission creatine kinase (115 x 10(3) U/l (1-316), median (range), versus 9 x 10(3) (0-91 ), p < 0.05 ), a higher admission creatinine (3.8 mg/dl (2.1- 6.7) versus 2.4 (1.4-8.1), p < 0.05 ), a higher peak creatinine kinase (129 x 10(3) U/l (2-316) versus 22 x 10(3) (3-197), p < 0.05), a lower urine output in the initial 24 hours (0.91/24 hrs (0.1-1.5) versus 3.9(1.0-11.1), p < 0.005) and a longer length of hospitalization (37 days (17-112) versus 12 (5-87), p < 0.05). No patient died and all patients had independent renal function at last review. The majority of patients had significant comorbidities. The incidence of serological evidence of exposure to blood-borne viruses was HIV 5% (n = 1), hepatitis B 10% (n = 2) and hepatitis C 74% (n = 17) of patients tested. Pneumonia occurred in 52% (n = 14) and 26% (n = 7) developed respiratory failure requiring intubation. 22% (n = 6) developed a compartment syndrome requiring fasciotomy and 37% (n = 10) had significant residual limb weakness at discharge.

CONCLUSION

There is an increase in patients admitted with rhabdomyolysis-induced renal failure associated with heroin use in our hospitals. We found a varied approach to an increasing clinical problem and suggest that a consistent investigative and therapeutic approach be introduced. Although renal recovery can be expected, long-term disability may occur due to potential serious complications.

Monitoring myoglobin by capillary zone electrophoresis with end-column amperometric detection

Capillary zone electrophoresis was employed for the determination of myoglobin in human urine using end-column amperometric detection with a carbon fiber microelectrode at a constant potential of 1.80 V vs. saturated calomel electrode (SCF). The optimum conditions of separation and detection are: 3.73 x 10-4 mol/L sodium diethyl malonyl urea (barbitone sodium), 1.34 x 10-4 mol/L HCl for the buffer solution, 20 kV for separation voltage, 5 kV and 5 s for injection voltage and injection time, respectively. The limit of detection is 4.4 x 10-8 mol/L or 84 amole signal to noise (S/N = 2). The relative standard deviation is 2.9% for the migration time and 2.5% for the electrophoretic peak current. The method can be used for the determination of myoglobin in human urine. The samples can be directly injected and need no pretreatment. The method is also rapid, less than 2 min, and has a recovery rate of 94-106%.

"Abdominal crunch"-induced rhabdomyolysis presenting as right upper quadrant pain

A young, active duty sailor presented with right upper quadrant abdominal pain. History, physical, and laboratory findings initially suggested cholecystitis or related disease. Further evaluation found myoglobinuria and a recently increased exercise program, leading to the diagnosis of exercise-induced right upper abdominal wall rhabdomyolysis. Although not a common cause of abdominal pain, this diagnosis should be considered in the patient with abdominal pain and a recently increased exercise program, particularly exercises of the abdominal wall such as "abdominal crunches."

Renal and liver functions and muscle injuries during training and after competition in Thai boxers

OBJECTIVE

To observe whether there are any injuries to muscle and deleterious effects on the liver and kidneys during training and after competition in Thai boxers.

METHODS

Serum levels of intracellular enzymes and specific markers in the urine were measured during training and after fighting in Thai boxers.

RESULTS

During the training period, the activities of muscle enzymes were significantly increased whereas those of the liver enzymes and creatinine clearance were not changed. After a match, on the other hand, both liver and muscle enzyme activities were elevated but renal function was decreased.

CONCLUSIONS

The training protocol for Thai boxers has virtually no deleterious effect on liver and renal function, but damage to skeletal muscle cells may occur. However, competition may cause muscle injury without any obvious damage to the liver and kidneys.

Acute renal failure due to traumatic rhabdomyolysis

Between 1990 and 1993, we studied 14 cases of acute renal failure due to prolonged muscular exercise (e.g., squat jumping, sit-ups) and blunt trauma inflicted by law enforcement personnel using sticks or leather belts. None of the patients had a prior history of myopathy, neuropathy, or renal disease. All were critically ill and required renal support in the form of dialysis. Although the morbidity was high, 13 of the patients recovered normal renal function. One patient expired due to sepsis.

Ultrafiltration discrepancies in recovery of myoglobin from urine

We investigated the efficiency, accuracy, and reliability of the ultrafiltration/dipstick methodology commonly used to diagnose myoglobinuria. Twenty-five myoglobin-containing urine specimens were filtered by centrifugation for 15 min at 1500g through a Centricon-30 membrane filter. Both the original specimen and filtrate were assayed for myoglobin. The amount of myoglobin recovered subsequent to filtration varied from <1-38%. This poor and variable recovery was independent of sample matrix or precentrifugation of the specimens. This was most critical for urine specimens with myoglobin concentrations <60 000 microg/L. Fourteen of 18 such filtrates had concentrations <350 microg/L, a concentration below which a negative result would be obtained by using conventional dipstick methods. Thus, the use of this procedure has the potential to misdiagnose patients with myoglobin concentrations associated with increased risk of subsequent renal dysfunction, in particular when urine myoglobin concentrations are <60 000 microg/L.

The role of fetal myoglobin in the initiation of human parturition

The aim of the present investigation is to study the effect of amniotic fluid myoglobin on prostaglandin synthesis by the fetal membranes. The paper presents results of radioimmunologic studies of myoglobin levels in various biological fluids during pregnancy: amniotic fluid, maternal serum samples obtained from an antecubital vein and the cervix, and neonatal urine. Amniotic fluid myoglobin levels were found to be significantly higher at term. Our results suggest that amniotic fluid myoglobin is likely to be derived from the fetus and excreted into amniotic fluid through fetal urine. Incubation of the fetal membrane with amniotic fluid, neonatal urine, and commercially available myoglobin enhanced phospholipase A2 activity, as well as arachidonic acid and prostaglandin F2 alpha production was compared to incubation with normal saline. The addition of anti-myoglobin antibodies to incubation media was found to block these effects. The results of our study show that myoglobin activates prostaglandin synthesis by the fetal membranes and stimulates the onset of labor.

Hypoestrogenemia and rhabdomyelysis (myoglobinuria) in the female judoist: a new worrying phenomenon?

It is now well established that strenuous engagement in aerobic endurance sports may cause menstrual problems and hypoestrogenemia-related phenomena, such as osteoporosis. The present study was designed to assess whether the competitive practice of female judoists produces specific physiological changes in menstruation and bone and muscle metabolism. A test group of 17 white female judoists (mean VO2max, 50.9 +/- 2.8 mL/kg.min; mean percent body fat, 16.3 +/- 3.3%), a reference group of oarswomen, and a group of sedentary women participated in this study. Specific metabolic parameters were determined before and after a heavy 5-week pre-Olympic training period. With regard to anthropometrical characteristics, after a period of intensive training, female judoists significantly differed (P < 0.05) from their pretraining values for percent body fat (-2.2%) and number of oligomenorrheic individuals (+28.4%). Mean baseline posttraining luteal phase plasma levels of estrone (78 +/- 26 pmol/L), estradiol (85 +/- 70 pmol/L), LH (7.6 +/- 2.8 IU/L), and progesterone (13.4 +/- 3.1 nmol/L) were significantly lower than those in both reference groups, although pretraining values did not significantly differ from those in a group of oarswomen. Luteal phase posttraining urinary parameters of muscular catabolism (3-methylhistidine, 367 +/- 30 mmol/day) and collagen turnover (hydroxyproline, 678 +/- 14 mumol/L) were significantly higher than those in a group of oarswomen (3- methylhistidine, 183 +/- 18 mmol/day; hydroxyproline, 196 +/- 21 micrograms/mL). Total plasma spontaneous monocyte interleukin-1 activity, an experimental parameter for bone turnover and formation, was significantly higher (P < 0.05) in both female judoists (15.8 +/- 3.0% max) and oarswomen (7.1 +/- 1.8% max) than in sedentary women (5.2 +/- 2.2% max). These findings were accompanied by a subjective feeling of musculotendinous soreness and fatigue. Posttraining values for blood diagnostic enzymes, such as creatinine phosphokinase, glutamic oxalacetic transaminase, lactic dehydrogenase, and uric acid exceeded 2-5 times maximal normal laboratory reference values. We believe that these overtraining-like findings should be further examined to study the eventual causal relationship between hypoestrogenemia and rhabdomyelysis (myoglobinuria) and to fully understand the extent of these results and their importance to the female athlete's health.

Mineral homoeostasis in acute renal failure complicating severe falciparum malaria

Disturbances in calcium metabolism in acute renal failure (ARF) remain incompletely understood. Most data are from patients with rhabdomyolysis. As renal impairment commonly accompanies severe malaria in the absence of rhabdomyolysis, falciparum malaria provides an alternative model of mineral homoeostasis in ARF. We studied 25 Vietnamese subjects, aged 18-63 yr, with severe malaria and 10 controls. Fourteen patients had a serum creatinine level of 250 mumol/L or less during treatment (group 1), five developed ARF but were not dialyzed (group 2a), and six required dialysis (group 2b). Group 1 patients presented with mild hypocalcemia (mean +/- SD serum ionized calcium, 1.18 +/- 0.05 vs. 1.23 +/- 0.02 mmol/L in controls; P = 0.01) that persisted until discharge in the presence of normal serum phosphate, PTH, and vitamin D metabolite levels. Group 2 patients were more hypocalcemic on admission (1.10 +/- 0.08 mmol/L; P < 0.0001 vs. controls), especially those in group 2b whose serum ionized calcium fell to 0.88 +/- 0.13 mmol/L when renal dysfunction was maximal. In group 2 patients, the admission serum PTH level was raised (5.4 +/- 3.8 vs. 2.7 +/- 0.9 pmol/L in controls; P < 0.02) and changed reciprocally with calcemia. Significant rises in serum phosphate occurred only in group 2b patients who had depressed serum free 1,25-dihydroxyvitamin D levels throughout. Hypercalcemia did not accompany the diuretic phase of ARF. These data suggest that parathyroid gland dysfunction is a cause of hypocalcemia in severe malaria without ARF, as seen in group 1 patients; in patients with ARF, the effect of the combination of phosphate retention and altered vitamin D metabolism on skeletal PTH sensitivity is of prime significance.

Myoglobinuria detection by capillary electrophoresis

Capillary electrophoresis was used in this study to separate urinary myoglobin from hemoglobin based on its electrophoretic mobility. Urine was applied directly without any treatment. The separation was accomplished in less than 7 min. Myoglobin extracted from human muscle tissues was separated, in a borate buffer 150 mM, pH 8.7 containing 0.5% polyethyleneglycol at 6 kV, into two peaks (MI and MII) which were also resolved far from hemoglobin. Upon standing at room temperature, MII converted into MI. Horse myoglobin eluted close to MI. The addition of polyethyleneglycol to the buffer enhanced the separation and increased the peak height of myoglobin. Optimum conditions for the separation are discussed. The method is suitable for routine clinical analysis because of its simplicity and speed.

Role of endothelin in acute renal failure due to rhabdomyolysis in rats

Rhabdomyolysis and other causes of massive myoglobin release are often complicated by an acute ischemic renal failure. We tested the hypothesis that endothelin-1, the most potent renal vasoconstrictor known, plays a role in the renal toxicity of myoglobin. For this purpose, we induced rhabdomyolysis (8 ml/kg i.m. of a 50% glycerol solution) in rats pretreated or not pretreated with bosentan, a novel potent nonpeptide endothelin receptor antagonist. Glycerol decreased renal function dramatically, increased proteinuria and induced a massive tubular necrosis. This effect was associated with a 22% increase in plasma endothelin concentration. Bosentan prevented the decrease in creatinine clearance (1.12 +/- 0.07 ml/min vs. 0.83 +/- 0.05 ml/min, P < .01), the increase in proteinuria (19.9 mg/24 hr vs. 31.8 mg/24 hr, P < .001) and the tubular necrosis induced by glycerol (as assessed by histopathological evaluation), without affecting myoglobinuria. Involvement of endothelin was further suggested by the observation that myoglobin could markedly increase endothelin-1 release by rat mesangial cells in culture. We conclude that endothelin is, at least in part, responsible for the massive tubular necrosis observed in myoglobinuric nephropathy.

Thrombotic thrombocytopenic purpura and myoglobinuric acute renal failure following radiation therapy in a patient with polymyositis and cervical cancer

A 73-year-old woman was admitted to receive radiation treatment for uterine cervical cancer, however a complex series of events ensued, leading to death. She developed an acute exacerbation of polymyositis complicated by thrombotic thrombocytopenic purpura, rhabdomyolysis and acute renal failure. Radiation therapy may have produced an immune disturbance leading to the acute exacerbation of polymyositis. Auto-immune-mediated endothelial damage might have triggered a series of events leading to thrombotic thrombocytopenic purpura. Rhabdomyolysis seemed to be the main cause of acute renal failure.

Immunoassays for serum and urine myoglobin: myoglobin clearance assessed as a risk factor for acute renal failure

We compared four immunoassays for serum and urine myoglobin. Within-run CVs were 5-13%, with biases seen between assays. Myoglobin was stable for 1 month in serum and 12 days in urine when the pH was adjusted to between 8.0 and 9.5. Hemoglobin caused no interference. We assayed 91 pairs of serum and timed urine specimens from 41 patients admitted for acute trauma or rhabdomyolysis. Most were treated with mannitol and alkalinization. Upon initial presentations, 21 patients with either low serum myoglobin concentrations (< 400 micrograms/L) or high myoglobin clearances (> or = 4 mL/min) had normal creatinine clearances and no clinical evidence of renal disease. The remaining 20 had low myoglobin clearances. Seven were in rhabdomyolysis-induced acute renal failure, or subsequently developed this complication. We suggest that low myoglobin clearance may indicate a high risk for developing renal failure or may be an early marker for kidney dysfunction. Low myoglobin clearance may prove useful in indicating failure of prophylactic treatment to clear myoglobin.

Physiologic amputation prevents myoglobinuria from lower extremity myonecrosis

Myoglobinuria secondary to myonecrosis is a proven cause of renal failure, especially in critically ill patients. Physiologic amputation or cryoamputation has been used at our institution for the past two decades as a safe and effective treatment for lower extremity infection, intractable rest pain, and irreversible myonecrosis. We retrospectively studied five critically ill patients with myonecrosis of lower extremities associated with myoglobinuria. The etiology of myonecrosis included preexisting peripheral vascular disease or crush injury to the lower extremities. It was determined that all five patients were too ill to undergo emergency amputation. Myoglobinuria was documented in all five patients and cleared within 24 hours of physiologic amputation in four patients. All five patients had elevated creatine phosphokinase levels (mean 20,270 mU/mL, range 12,090 to 43,164 mU/mL) that significantly decreased within 48 hours of physiologic amputation (mean 6,488 mU/mL, range 2,250 to 13,580 mU/mL). Mechanical ventilation and cardiovascular support were required in four patients. All patients had transient episodes of renal insufficiency with two progressing to anuric renal failure and requiring dialysis. One patient's renal failure resolved after 56 days, but the other patient died of a cerebrovascular accident 22 days after initiation of physiologic amputation. The mean duration of physiologic amputation was 15.6 days (range 5 to 32 days) with no significant complication due to physiologic amputation. All five patients had surgical amputation successfully. Three patients survived. The two deaths in the study were due to a cerebrovascular accident in one patient and a cardiopulmonary arrest in another. Physiologic amputation is a treatment option that halts myonecrosis, prevents myoglobinuria, and lessens the risk of associated acute renal failure. Physiologic amputation may be appropriately used in patients with myoglobinuria due to extremity myonecrosis who are deemed too critically ill to survive emergency amputation.

[Arterial reconstructive surgery and myoglobin]

To assess the diagnostic value of myoglobin between elective surgery and acute arterial occlusion, serum and urine myoglobin (S-Mb, U-Mb) levels were measured before and for 7 consecutive days following arterial reconstructive surgery in 7 patients with abdominal aortic aneurysm or arteriosclerosis obliterans (elective surgery group), and in 20 patients with acute arterial occlusion due to embolism or thrombosis. They were divided into three groups based on symptoms and other features: mild, moderate, and severe groups. S-Mb and U-Mb levels were normal before surgery with a maximum of 389 ng/ml and 1,670 ng/ml after surgery in the elective surgery group, and 489 ng/ml and 11.7 ng/ml before surgery with a maximum of 703 ng/ml and 294 ng/ml after surgery in the mild cases. These two groups showed no complications after surgery. In the moderate group, high values of 2,420 ng/ml and 25,300 ng/ml were noted before surgery, and these values were elevated to 14,900 ng/ml and 175,000 ng/ml after surgery with complications of acute renal failure or peripheral nerve paresis. In the severe group, the values were 9,440 ng/ml and 260,000 ng/ml before surgery, and 160,000 ng/ml and 1,300,000 ng/ml after surgery, the elevation being associated with the severe clinical complication, myonephropathic metabolic syndrome (MNMS). All patients in this group died of MNMS. S-Mb and U-Mb levels before surgery proved useful for predicting the prognosis of patients with acute arterial occlusion. The findings obtained in our canine studies on the mechanism and treatment of MNMS suggest that alpha-tocopherol, a free radical scavenger, may be effective for treating dreadful complications such as MNMS.

Rhabdomyolysis and myoglobinuric renal failure

Rhabdomyolysis, a clinical syndrome resulting from the release of skeletal muscle cell contents into the plasma, is causally connected to up to 25 percent of all cases of acute renal failure. Critical care nurses need to be aware of precipitating factors and proper interventions in order to assure optimal function in this patient population.

Idiopathic myoglobinuria in the early puerperium

Myoglobinuria is rare in association with pregnancy. We report a case of idiopathic myoglobinuria in the early puerperium in a patient who had a spontaneous vaginal delivery. Acute muscular pain and port wine staining of the urine should alert the clinician.

Rhabdomyolysis: clinical analysis of 20 patients

Twenty patients with rhabdomyolysis with and without acute renal failure (ARF) were studied. The patients consisted of 9 males and 11 females with a mean age of 64.5 +/- 3.2 years. Infection, compression and metabolic derangement were implicated as the most common etiologic factors. While 7 patients developed ARF during hospitalization, renal functions were normal in the remaining 13. While the mean ages, serum ARF, significant increases in potassium, phosphate, blood urea nitrogen, creatinine and uric acid were observed. While the mean blood pressure was similar, significant increases in hematocrit and total protein were observed in the patients with ARF. The detailed results indicated that infection, compression and metabolic derangement were the most common etiology factors of rhabdomyolysis, and plasma volume contraction might be responsible for the development of ARF.

Rapid separation and identification of myoglobin and hemoglobin in urine by centrifugation through a microconcentrator membrane

Urinary myoglobin (Mr = 16 500) is readily separated from hemoglobin (Mr = 64 000) by centrifugation through a microconcentrator membrane with a 30 000-Da cutoff. Myoglobin, but not hemoglobin, will pass through the membrane, after which each fraction may be separately analyzed by spectrophotometry. This technique is advantageous over direct spectrophotometry of urine because it is not restricted to analyzing the oxy forms of these hemoproteins and obviates the difficulty of discriminating small (3 nm) differences in their spectra. In addition, this method of separation is more complete than that attained by differential "salting out" with ammonium sulfate, and it is simpler than gel filtration or ultrafiltration under reduced pressure.

Myoglobin determination by high-performance liquid chromatography

Urine and serum myoglobin have been separated on an anion-exchange column, packed by the slurry technique. Urine or serum was injected directly into the column and eluted isocratically with Tris buffer. Freshly prepared myoglobin from human muscle gives two peaks in the chromatogram. Upon storage, one peak slowly decreases while the other increases in size and has the same capacity factor as horse myoglobin. In myoglobinuria, the latter peak is usually detected in urine, while in serum both peaks are detected. For routine assays, horse myoglobin is used as a standard. The minimum detectable level is 2 mg/l. Urine myoglobin from patients with myoglobinuria ranged from 20 to 3000 mg/l, while normal subjects had undetectable levels. Patients with myoglobinuria also had detectable levels of myoglobin in their serum. Urine myoglobin was found to be unstable; it should be analyzed immediately. Although the present method is not sensitive enough to detect myoglobin in the urine of normal subjects, it is clinically useful for confirming and determining myoglobin in patients with myoglobinuria. It has the advantage of speed and simplicity. Using more sensitive detectors would enhance the usefulness of this method.

Low fractional excretion of sodium. Occurrence with hemoglobinuric- and myoglobinuric-induced acute renal failure

Ten patients with myoglobinuric and hemoglobinuric acute renal failure demonstrated low fractional excretion of sodium (FENa) values (less than 1%) during the oliguric phase of their course. Acute renal failure secondary to hemoglobinuria developed in five patients, and five demonstrated acute deterioration with myoglobinuria. The mean serum creatinine level increased from 1.1 mg/dL (range, 0.6 to 1.7 mg/dL) to a maximum of 6.9 mg/dL (range, 2 to 13.1 mg/dL). Although three patients required dialysis, all individuals eventually returned or were returning toward their baseline renal function at discharge. The importance of a low FENa in the setting of myoglobinuric and hemoglobinuric renal failure is reviewed. The findings in this report raise the possibility that a common mechanism may underlie the renal injury in both types of pigment toxicity.

Assay of urinary N-acetyl-beta-glucosaminidase in a centrifugal analyzer

We describe a kinetic, fluorometric assay for urinary N-acetyl-beta-glucosaminidase (EC 3.2.1.30) by measurement of the release of 4-methylumbelliferone (7-hydroxy-4-methylcoumarin). The method is simple, involving only a single reagent, and is applicable to the assay of other enzymes that hydrolyze similar fluorescent-labeled substrates. The enzyme distribution in human tissues and fluids is described. The enzyme is present in high concentrations in human kidney, liver, and lung. Its concentration in urine is shown to be a sensitive indicator of early renal damage, which precedes changes in serum creatinine and urinary protein. Assay of the enzyme is quite useful in monitoring renal damage due to myoglobinuria.

Myoglobinemia in the early phase of acute myocardial infarction

Close-meshed determinations of plasma myoglobin, creatine kinase, and its isoenzyme MB were carried out in nine patients admitted to the clinic less than 4 hours after the onset of symptoms in the course of acute myocardial infarction (AMI). Myoglobin clearly appears earlier (mean 2 hours and 30 minutes) in the plasma than creatine kinase (mean 4 hours and 15 minutes) and isoenzyme MB (mean 5 hours and 30 minutes after the onset of symptoms). During the first hours of AMI plasma myoglobin shows multiple peaks in all patients. Because this pattern is observed only with myoglobin but not with creatine kinase, it appears that myoglobin mirrors the early course of the necrosis more distinctly than creatine kinase. Plasma myoglobin was also found elevated after intramuscular injections and a high voltage accident. Myoglobinuria was not detectable after myocardial infarction.

Limitations of conventional laser nephelometry for the measurement of beta 2-microglobulin, lysozyme, alpha 1 fetoprotein and myoglobin in serum and urine

We have tested some assay procedures for the measurement of beta 2-microglobulin, lysozyme, alpha 1-fetoprotein and myoglobin in serum and/or urine with the use of a manual Behring laser nephelometer. The assay working ranges were: beta 2-microglobulin: 0.0038-0.038 g/L; lysozyme: 0.005-0.325 g/L. We have studied the effect of different antiserum dilution ratios and of different concentrations of polyethylene glycol 6000 on the calibration curves. The best standard curves were obtained with the use of the following antiserum dilutions: anti-beta 2-microglobulin: 1:3 with saline, 40 g/L PEG; anti-lysozyme: 1:5 with saline, 40 g/L PEG; anti alpha 1-fetoprotein: concentrated; anti-myoglobin: concentrated with added 40 g/L PEG. In the case of beta 2-microglobulin and lysozyme, laser nephelometry, could be a fast and simple procedure if a 10 times increase in sensitivity can be achieved. For the measurement of alpha 1-fetoprotein and myoglobin, the sensitivity of laser nephelometry was disappointing when compared to those reported for radioimmunoassay and enzyme immunoassay.

Influence of pH on the simple solubility test for myoglobinuria

We have investigated the effect of urine pH on the simple solubility test for myoglobinuria and found that the sensitivity of the test is very pH dependent. As much as a 10 fold increase in sensitivity can be obtained if the test is performed at pH 7.5 instead of pH 5.5. As such, we recommend that the urine pH should first be adjusted within the range 7.5--8.0 before performing the solubility test for myoglobinuria.

[Study of the changes in kidney function in acute obstruction of the arteries of the extremities]

The kidney function was studied in postischemia period in 80 patients with acute arterial occlusion,using the methods of radioisotope renography and effective renal blood flow. For the purpose of prophylaxis agains renal complications in addition to regional perfusion and venesection the method of regional inhibition of toxic products in the ischemia focus is suggested. In increased myoglobinuiea the stimulation of diuresis, alkalization of the organism would be a necessity. Renal complications were observed in 13 of 80 patients (16.25%). In 6 patients myoglobinuric tubular nephrosis was noted with lethal issues; in the remaining 7 patients due to early establishment of the diagnosis and intensive therapy myoglobinuria showed an abortive character.