OB Patients Research Articles

Mechanisms of Microvascular Endothelial Dysfunction in Subcutaneous Fat during Human Obesity

Microvascular endothelial dysfunction contributes to cardiovascular disease risk during obesity. Inflammatory cytokines (CRP and IL‐6) and NADPH oxidase generation of reactive oxygen species (ROS) reduces endothelial function during obesity. Therefore, we hypothesized that pro‐ inflammatory cytokines and NADPH oxidase generation of ROS contribute to microvascular dysfunction in subcutaneous (SQ) fat during obesity. Isolated resistance arteries were obtained from SQ biopsies in lean (LN; BMI<27) and during laproscopic band surgery in obese (OB; BMI>40) women (mean age: 36±1). Microvessels were cannulated for vascular reactivity measurements to acetylcholine (ACh; 10−9‐10−4 M) in the absence and presence of the SOD mimetic Tiron (10−4 M), NADPH oxidase inhibitor apocynin (10−6 M), and the xanthine oxidase inhibitor allopurinol (10−4 M). Superoxide production was assessed with hydroethidine fluorescence in the presence and absence of the same inhibitors. Blood measurements of CRP and IL‐6 were determined with ELISA. Maximum dilation to ACh was reduced in OB (46 ± 6%; n=9; p<0.05) vs. LN (79 ± 9%; n=5) patients and was restored by Tiron. Superoxide production was increased in microvessels from OB subjects. Tiron and apocynin restored the dilator response to ACh and reduced baseline and ACh‐ stimulated superoxide fluorescence of OB. Allopurinol had no effect on ACh responses in OB microvessels. There was no association between IL‐6 or CRP and superoxide fluorescence. These data indicate that NADPH oxidase generation of ROS impairs endothelial function in SQ microvessels during obesity.

Communication plays key role in OB patient expectations

Obstetrics is a medical specialty with high profesional liability exposure. Every aspect of an adverse OB outcome has become an opportunity for a legal review. Common root causes in adverse outcomes include communication failure, poor teamwork, and system failures. Indeed, poor communication is a significant factor in OB-related malpractice claims. This excerpt from the booklet Risk Management Pearls for Obstetrics highlights those causes (particularly poor communications) and provides strategies to address them.

Oral Breathing and Head Posture

To determine the head posture and cephalometric characteristics in oral breathing children. Lateral cephalograms taken in natural head posture of 35 oral breathing patients (OB) (mean age 8.8 +/- 2.2 years SD; range 5-13 years) and of 35 patients with varied malocclusions and physiological breathing (PB) (mean age 9.7 +/- 1.6 years SD; range 7-13 years) were examined. A Student's t-test showed that an increase in angles NSL/OPT (P = .000), NSL/CVT (P = .001), FH/OPT (P = .000), FH/CVT (P = .005), and NSL/VER (P = .000); a decrease in the distance MGP-CV1p (P = .0001); and a decrease in the angles MGP/OP (P = .000) and OPT/ CVT (P = .036) were found in the OB group. A low position of the hyoid bone (H-MP, P = .009), a major skeletal divergence (ANS-PNS/Go-Me, P = .000), and an increased value of the ANB angle (P = .023) were present in OB patients. To ascertain if the changes in posture were connected with posterior obstruction of the upper respiratory airways, the OB group was divided into two subgroups based on the distance Ad2-PNS being greater than or less than 15 mm. No significant differences were found between these two groups. Our data suggest that OB children show greater extension of the head related to the cervical spine, reduced cervical lordosis, and more skeletal divergence, compared with PB subjects.

Obesity Does Not Affect Mortality after Trauma

Although obesity has been proposed as a risk factor for adverse outcomes after trauma, numerous studies report conflicting results. The objective of this study was to compare outcomes of obese and nonobese patients after trauma. The study population consisted of all trauma patients admitted to a surgical intensive care unit in a Level I trauma center from January 1999 to December 2002. Admission data, demographics, injury severity score (ISS), severity of illness, hospital course, complications, and outcomes were compared between obese (OB; body mass index [BMI] > or = 30), and nonobese patients (NOB; BMI < or = 29). A total of 918 patients was included in the study, 135 OB (14.7%) and 783 NOB (85.3%). There was no significant difference in demographic data, ISS, APACHE II score, and hospital stay. Intensive care unit stay was longer for OB patients (6.8 vs 4.8 days, P = 0.04). Overall mortality was 5.9 per cent for OB and 8.0 per cent for NOB patients (P = 0.48). Mortality by mechanism of injury was 3.4 per cent OB versus 7.4 per cent NOB (P = 0.26) for blunt and 10.6 per cent OB versus 10.2 per cent NOB (P = 0.9) for penetrating injury. The three most common complications associated with death were pulmonary, cardiovascular, and neurological deterioration. Using logistic regression analysis, age and ISS and APACHE II scores were associated with mortality, but BMI was not. We conclude that obesity does not appear to be a risk factor for adverse outcomes after blunt or penetrating trauma. Further research is warranted to uncover the reason for discrepant findings between centers.

Effect of Obesity on Presentation of Breast Cancer

Obesity has been shown to be associated with reduced survival in patients with invasive breast cancer (IBC), although the mechanisms for this finding are unclear. The objective of this study was to examine the effect of obesity on the presentation and pathologic staging of IBC. From February 15, 2002, to February 15, 2004, all patients undergoing surgery for primary IBC at two institutions were enrolled in a prospective cohort study. National Institutes of Health criteria were used to categorize patients: normal or underweight (NW; body mass index <25 kg/m(2)), overweight (OW; body mass index 25-29.9 kg/m(2)), and obese or severely obese (OB; body mass index > or =30 kg/m(2)). Presentation and pathologic factors were then compared among groups. The study cohort consisted of 519 patients; 166 (32%) were NW, 177 (34%) were OW, and 176 (34%) were OB. OW (46%) and OB (39%) patients were more likely to be diagnosed with IBC via screening mammography compared with NW (31%) patients (P = .01), although no differences were found between groups with respect to previous use of screening mammography. Aggressive pathologic features, including lymph node metastases, advanced tumor-node-metastasis stage, and grade were found more commonly among OB patients. OW and OB patients were more likely to receive a diagnosis via screening mammography, thus suggesting that mammography may play a more important role in OW and OB patients. Despite this, OB patients presented with larger, more advanced tumors; this may help to explain obesity-associated survival differences in IBC patients. This is important information given the prevalence of obesity in North America.

Impact of body mass index on biochemical outcomes after definitive therapy for localized prostate cancer

4658 Background: We reviewed the impact of body mass index (BMI) on biochemical relapse-free survival (bRFS) after external beam radiation therapy (EBRT), brachytherapy (B), and radical prostatectomy (RP) for clinical T1-T3 prostate cancer in a large single institution cohort. Methods: The study included 1036 treated (1992–1999) patients from our prospectively managed database. No cases received neoadjuvant or adjuvant hormonal therapy. Biochemical failure (BF) was defined as a PSA >0.2 or two consecutive PSAs of 0.2 after RP and by ASTRO definition for RT (EBRT and B). Kaplan-Meier and Cox-proportional hazards analyses were used to determine if BMI predicted BF or adverse pathology. Results: The 9-year bRFS for normal (n=281), overweight (n=524), and obese (n=231, OB) was 68%, 72%, 63%, respectively (p=0.0072). The median PSA follow-up was 76 months (range: 24 to 150). Obesity (BMI ≥ 30) was not associated with higher bGS. OB adversely impacted bRFS on univariate analysis (p=0.0079), but after controlling for all preop clinical variables (T-stage, iPSA, bGS), OB did not significantly predict BF. Amongst 517 RP patients, OB was significantly associated with positive margins (PM) (p=0.0014), seminal vesicle invasion (SVI) (p=0.0625), and extracapsular extension (ECE) (p=0.0702), but not with surgical Gleason score (sGS). The 9-year bRFS rate for normal, overweight, and OB was 73%, 73%, 66%, respectively (p=0.0323). In the univariate, BMI was a predictor of bRFS (p=0.0358). In the multivariate, BMI was a significant risk factor of bRFS (p=0.0069) after controlling for T-stage (p<0.0001), iPSA (p=0.0014), bGS (p<0.0001). However, after controlling for PM, SVI, ECE, sGS, BMI was not significant for BF. Of the patients who had RT (n=519), EBRT (n=392), or B (n=127), BMI was not a predictor of BF. Conclusions: OB men do not have an inherently more aggressive form of prostate cancer in this dataset. Although BMI ≥ 30 adversely impacted bRFS on univariate analysis, it was not associated with increased risk of bRFS after controlling for clinicopathologic characteristics. RP in OB patients was significantly associated with adverse path features, perhaps related to technical difficulties. No significant financial relationships to disclose.

Body composition and cardiovascular risk factors in pretransplant hemodialysis patients

Background: Obesity, hyperlipemia and cardiovascular complications contribute to a significant proportion of morbidity and mortality of renal transplant patients and have negative effects on renal survival. Aim of the present study was to evaluate the main abnormalities in body composition and the prevalence of some cardiovascular risk factors in a population of hemodialyzed (HD) patients awaiting renal transplantation. Methods: We studied 151 HD patients, all included in a waiting list for renal transplantation, 97 males and 54 females, with mean age 47.4±12 years. Patients were divided into three groups according to their body mass index (BMI) (kg/m 2): 18.5 to 24.9 (normoweight, NW); 25.0 to 29.9 (overweight, OW); ⩾30 (obese, OB). The body composition measurements were obtained the day after the mid-week HD session using bioelectrical impedance analysis (BIA). Results: We found that 47 patients were NW (31%), while 56 were OW (37%), and 48 were OB (32%). BIA-measured body cell mass was (BCM) significantly increased in the OW as compared with the NW group ( P<0.001), but, of note, no significant difference was found in OB group in comparison with the OW. Total cholesterol and triglycerides plasma levels were significantly elevated in OW and OB patients with respect to NW ( P<0.05) and an increased prevalence of diabetes was seen in OB patients (NW: 6%, OW: 5%, OB: 12%). Conclusions: These data show that a large proportion of patients awaiting renal transplant are overweight or obese and a consistent part of them have other cardiovascular risk factors associated. Furthermore, obese HD patients have a BCM lower than predicted on the basis of BMI and show an altered metabolic profile. A better understanding of the characteristics of patients included in the renal transplant waiting list is crucial in order to design prospective studies that aim to define the proper risk profile for the selection of patients.

Testosterone levels in obese male patients with obstructive sleep apnea syndrome: relation to oxygen desaturation, body weight, fat distribution and the metabolic parameters.

To investigate the impact of obstructive sleep apnea syndrome (OSAS) on testosterone levels and on the main parameters of the metabolic syndrome in abdominally obese men, 15 male subjects with abdominal obesity phenotype and polysomnographic diagnosis of OSAS (OB-OSAS) and 15 controls matched for age and anthropometric parameters (OB) were investigated. Anthropometry, SHBG, sex hormones and several parameters of the metabolic syndrome were measured. Only subjects with an Epworth Sleepiness Score greater than 10 underwent a polysomnographic study with calculation of the number of desaturation rates per sleeping hour (ODI), the minimal oxygen saturation during each desaturation episode (minSaO2) and the mean minimal arterial oxygen saturation for the whole night period (MminSaO2). Both total and free testosterone levels were lower in OB-OSAS than in OB patients. A negative correlation between polysomnographic parameters (ODI, minSaO2 and MminSaO2) and testosterone levels was found. The relationship between total and free testosterone and ODI persisted after adjusting for body mass index (BMI) and waist (W) values. Triglyceride and uric acid levels were significantly higher in OB-OSAS than in OB patients. A negative correlation between testosterone and acid uric level and a positive correlation between testosterone and HDL-cholesterol level was found, regardless of BMI and W circumference, particularly in the OB-OSAS group. Our study suggests that, in patients with obesity and OSAS, the severity of hypoxia during sleeping hours may be an additional factor in reducing testosterone levels, regardless of BMI and abdominal fatness. This may contribute in worsening metabolic abnormalities which, in men with OSAS, exceed those expected on the basis of degree of obesity and pattern of fat distribution.

Cardiac anomaly identification in either a general OB/GYN office or maternal fetal medicine

Objective: We conducted a descriptive study of the identification of structural heart defects in a population based on whether prenatal ultrasounds were performed by Maternal Fetal Medicine (MFM) or by general OB providers. Methods: Our neonatal database was queried to identify all neonates with structural congenital heart disease. These fetuses were then cross-referenced with the MFM database to see if they had been scanned prenatally. Indications and findings were noted. Patients not found in both databases were assumed to have not been scanned in MFM. This is a population-based study as Woman’s Hospital provides obstetric and neonatal services for more than 90% of the Baton Rouge community. Infants with postnatal arrhythmias or pericardial effusions were excluded. Results: A total of 137 infants met criteria for inclusion. 46 of 137 were evaluated by MFM. 4/46 studies in MFM were referred as a result of suspected congential heart disease. General OB patients included 10/91 with ASD, 36/91 with VSD, 22/91 with complex congenital heart disease, 16/91 with pulmonary stenosis, and 2 with aortic stenosis. 5 cases were excluded because the lesions were thought unlikely to be identified prenatally (anomalous pulmonary return, coarctation, and valvular dysfunction). In the MFM population, 14/17 fetuses with complex lesions were identified. Of the 3 missed: 1 was seen at 36 weeks, one was seen at 17 weeks, and the third was missed despite multiple studies. Of infants with an ASD, only 1/7 was identified and only 8/18 infants with a VSD were picked up. Pulmonary stenosis was identified in 2/3 cases. Postnatal review by cardiology suggests less than half of the missed VSD/ASDs could have been seen prenatally given the postnatal size. Conclusions: 1) 4/22 (18%) patients with complex congenital heart disease were referred for fetal echocardiogram from the community, while 10/13 (77%) were identified in MFM. 2) ASD/VSD identification was poor in both groups. 3) This review confirms multiple prior reports demonstrating poor identification of cardiac lesions in a general Ob/Gyn setting and suggests the only means to improve prenatal identification is liberalization of referral to specialty centers.

Forum: AAMS, AMPA, ASTNA, NEMSPA, NFPA

Forum: AAMS, AMPA, ASTNA, NEMSPA, NFPA

Peripheral airway smooth muscle mechanics in obstructive airways disease.

The purpose of this study was to determine whether altered airway smooth muscle (ASM) contractility contributes to the pathogenesis of obstructive airways diseases such as chronic obstructive pulmonary disease (COPD) and asthma. The passive and active mechanical properties of isolated human peripheral airways were measured in vitro by myography. The amount of ASM was measured by morphometry. Pulmonary function was assessed before surgery by the FEV(1) (%pred) and the FEV(1)/ FVC (%). Fifteen airways were studied from nonobstructed (NOB) patients, and 15 from obstructed (OB, FEV(1)/FVC < 70%) patients (62 +/- 10 yr, mean +/- SD). The maximal isometric force (Fmax), stress (Fmax/ASM), airway diameter at Lmax (Dmax), maximal isotonic shortening (%Lmax), and normalized airway smooth muscle (ASM/Dmax) were determined in all patients. There was a significant correlation between Fmax and FEV(1) (%pred) (r = -0.579, p < 0.004), between Fmax and FEV(1)/FVC (%) (r = -0.720, p < 0.003), and between stress and FEV(1)/FVC (%) (-0.611, p < 0.002). There was no correlation between isotonic shortening and either measure of pulmonary function. A positive correlation was found between force and shortening (r = 0.442, p < 0.05), and stress and shortening (r = 0.538, p < 0.01). Both force and stress were significantly increased (p < 0.05) in OB (Fmax = 0.87 +/- 0.8 g, stress = 76 +/- 47 mN/mm(2)) versus NOB (Fmax = 0.42 +/- 0.18 g, stress = 51 +/- 21 mN/mm(2)) patients, while isotonic shortening was not different between the two groups. ASM and ASM/Dmax were both significantly increased in the OB patient group (p < 0.05). These results suggest that obstructive airways disease is associated with an increase in the ability of the ASM to generate force. (Values represent means +/- SD.)

Addressing Obesity In Ambulatory Care: Is Physician Awareness The Problem ?

LEARNING OUTCOME: to recognize the value of assessing current physician behavior for the development of a focused, practical nutrition education programDespite a recent national focus on health and fitness Americans are becoming fatter. Current studies estimate 30% of the adult population is overweight. Using height and weight data, a survey of our internal medicine resident's clinic revealed a 54% prevalence of obesity (n= 1160 patient visits). Although it is well recognized that excess body weight complicates the management of several medical conditions, housestaff appeared to pay little attention to obesity as a comorbid medical problem. This study was devised to define the frequency with which the housestaff addressed and documented the following factors: obesity as part of the history or physical exam, obesity as a distinct problem in the problem list or assessment, and intervention directed at obesity. We reviewed 1234 randomly selected patient records in an internal medicine resident's clinic. Obesity, defined as a body mass index (BMI) of >29.5 kg / m2, was identified in 55.6% of patients. The clinic notes of 559 obese (Ob)[mean BMI =37.0 kg/m2] and 106 normal to moderately overweight [mean BMI =27.2 kg/m2] patients were reviewed in detail. Obesity was documented in the history or physical exam of 29.7% of Ob patients, was listed as a distinct problem or in the assessment of 7.9% of these patients, and intervention for obesity was noted in 6.8% of Ob clinic notes. Hypertension (66% vs 47%) and diabetes (37% vs 27%) were noted more frequently in Ob vs. nonobese patients. Although the prevalence of obesity in our clinic is higher than that of general population, housestaff infrequently addressed obesity as a problem and intervention was rarely noted. Because moderate reductions in body weight can improve control of several medical conditions, teaching physicians to address obesity as a distinct problem could notably impact overall patient care. As a result of this study, an educational program is being developed to increase houseofficer awareness of obesity and to provide easy access for referral of patients to classes and counseling by a trained dietician

Effects of acipimox, an antilipolytic drug, on the growth hormone (GH) response to GH-releasing hormone alone or combined with arginine in obesity

Increased free fatty acid (FFA) levels of obese patients are likely involved in the pathogenesis of the growth hormone (GH) hyposecretion of obesity. To clarify their role, we studied the influence of inhibition of plasma FFA levels, induced by 500 mg oral acipimox (ACX), an antilipolytic drug, on the GH response to GH-releasing hormone (GHRH) alone or combined with arginine ([ARG] study A) in six normal women ([NS] aged 24 to 37 years; body mass index, 22.4 ± 0.9 kg/m 2) and six obese women ([OB] aged 21 to 40 years; body mass index, 39.5 ± 3.2 kg/m 2). In a group of seven OB patients (aged 18 to 58 years; body mass index, 35.8 ± 1.3 kg/m 2), the effect of ACX on either the GHRH- or GHRH+ARG-stimulated GH increase was also studied after a 4-day treatment with the same drug at 250 mg three times daily (study B). OB patients had baseline FFA levels higher than NS (0.77 ± 0.06 v 0.44 ± 0.09 mol/L, P < .05). In study A, ACX reduced FFA levels to the same nadir in both groups (0.11 ± 0.02 and 0.12 ± 0.03 mmol/L, NS and OB subjects, respectively). In NS, ACX failed to significantly potentiate the GH response to either GHRH (1,371.9 ± 425.2 v 1,001.8 ± 229.0 μg/L · min) or GHRH+ARG (3,558.4 ± 1,513.7 v 3,045.9 ± 441.8 μg/L · min), while in OB patients it increased the GH response to GHRH (797.6 ± 277.3 v 353.8 ± 136.7 μg/L · min, P < .01) and did not modify the response to ARG+GHRH (1,010.5 ± 253.1 v 821.1 ± 222.0 μg/L · min). In study B, ACX reduced FFA levels in OB patients (nadir, 0.09 ± 0.04 mmol/L). This treatment strikingly increased the GH response to GHRH (1,734.0 ± 725.4 v 271.5 ± 112.8 μg/L · min, P < .01) and significantly potentiated that to ARG+GHRH (2,371.9 ± 571.3 v 1,020.0 ± 343.2 μg/L · min, P < .05). In conclusion, our present findings indicate that an acute reduction of plasma FFA levels in OB patients restores their somatotrope responsiveness, whereas it does not affect GH secretion in lean subjects. After prolonged treatment, ACX further improves GHRH-stimulated GH secretion in OB patients, suggesting that elevated FFA levels play a leading role in the GH hyposecretory state of obesity.

Generations of Suffering: Drug Use During Pregnancy

Substance abuse during pregnancy represents a major threat to both women and their infants. Medical complications, including anemia, cardiac disease, cellulitis, edema, hepatitis, phlebitis, pneumonia, cystitis, urethritis, and pyelonephritis, are seen in nearly 50 percent of pregnant drug-dependent women. Major effects on the fetus include intrauterine death, overwhelming infection, chorioamnionitis, premature rupture of the membranes, poor fetal growth, and low birthweight with associated complications. Infants born to drug-abusing parents are at heightened risk for physical abuse and neglect, learning disabilities, and behavioral problems. There is clear evidence that drug use during pregnancy is a widespread and growing problem among the inner-city poor. In Hartford, CT, for example, current estimates by substance abuse treatment counselors and neighborhood prenatal care providers are that, depending on the neighborhood, seven to 50 percent of pregnant women use teratogenic mind-altering substances. A recent study of 51 mothers of low-birthweight babies who were local OB/GYN clinic patients found that 65 percent reported substance use during pregnancy, while a survey of 1,000 consecutive OB patients at one inner-city hospital found that 12 percent used illicit drugs. These data point to the need for well-coordinated drug treatment efforts for pregnant and postpartum women. This paper describes one such program, Project Recovery in Hartford, a comprehensive treatment program designed and implemented through a consortium of community-based organizations and hospital-based drug treatment providers. The paper reviews the life histories and drug use patterns of project participants and describes the components of the project developed to meet the intertwined social, economic, and health needs of project participants. Drug use during pregnancy is seen and handled in the project as a symptom of a more encompassing problem: the health crisis of the urban poor. Responding to the interconnected nature of this crisis requires long-term, multifaceted intervention, as evidenced by the several components of Project Recovery.

A Nurse Practitioner Program For Womenʼs Health Care

-| ! Xsity of Colorado School of Nursing prepares nurses to give comprehen_ _!. X _ sive, quality health care to women . ~!::~: ~ x_:'~/~~--~~~--~ ~ from adolescence through menopause. Graduates of all types of nursing programs, AD to MS, are considered for admission, and applicants are encouraged to have at least one year of clinical experience in some area of obstetrics or gynecology. Candidates are screened carefully. The program, set up under the continuing education department, is designed for adult learners. Students are encouraged to identify and focus on individual learning needs and to experience an adult growth process during the course. The didactic portion of this course is only the beginning of the learning process, and students are urged to continue learning by reading journals and pertinent literature and by attending continuing education offerings in their special interest areas. Students complete the following six modules: 1. Core-four weeks of history taking and physical examination skills. 2. Ambulatory obstetricsthree weeks in an outpatient clinic setting, seeing both new and return OB patients. 3. Intrapartum-two weeks in

A Nurse Practitioner Program for Women's Health Care

-| ! Xsity of Colorado School of Nursing prepares nurses to give comprehen_ _!. X _ sive, quality health care to women . ~!::~: ~ x_:'~/~~--~~~--~ ~ from adolescence through menopause. Graduates of all types of nursing programs, AD to MS, are considered for admission, and applicants are encouraged to have at least one year of clinical experience in some area of obstetrics or gynecology. Candidates are screened carefully. The program, set up under the continuing education department, is designed for adult learners. Students are encouraged to identify and focus on individual learning needs and to experience an adult growth process during the course. The didactic portion of this course is only the beginning of the learning process, and students are urged to continue learning by reading journals and pertinent literature and by attending continuing education offerings in their special interest areas. Students complete the following six modules: 1. Core-four weeks of history taking and physical examination skills. 2. Ambulatory obstetricsthree weeks in an outpatient clinic setting, seeing both new and return OB patients. 3. Intrapartum-two weeks in

Evaluation of urinary myoglobin assay test for myocardial infarction

Serial determinations of urinary myoglobulin, beta2-microglobulin and albumin, and of serum myoglobin, were performed in twenty-eight consecutive patients admitted to a coronary care unit. Patients with myocardial infarction (MI patients) all had higher serum levels of myoglobin then those with other diagnoses (OBS patients). Myoglobinuria occurred in 80% of MI patients and in half of the OBS patients. The appearance of myoglobin in urine was mainly accounted for by an impaired renal reabsorption of low molecular weight proteins. Measurement of urinary myoglobulin, in contrast to serum myoglobulin, is of little value for the diagnosis of myocardial infarction.

Evaluation of urinary myoglobin assay test for myocardial infarction

Serial determinations of urinary myoglobulin, β2-microglobulin and albumin, and of serum myoglobin, were performed in twenty-eight consecutive patients admitted to a coronary care unit. Patients with myocardial infarction (MI patients) all had higher serum levels of myoglobin then those with other diagnoses (OBS patients). Myoglobinuria occurred in 80% of MI patients and in half of the OBS patients. The appearance of myoglobin in urine was mainly accounted for by an impaired renal reabsorption of low molecular weight proteins. Measurement of urinary myoglobulin, in contrast to serum myoglobulin, is of little value for the diagnosis of myocardial infarction.