The office management of recurrent urinary tract infection and vesicoureteral reflux in children

Recurrent urinary tract infections (UTIs) and vesicoureteral reflux are common diagnosis' in infants and children who are referred to a urologist. Recurrent UTIs in these patients can be challenging, especially when radiographic evaluation reveals no structural abnormality. Prophylaxis and correction of voiding and bowel dysfunction are important treatment strategies. Febrile UTIs are commonly associated with reflux and should be treated aggressively to avoid renal scarring and its sequelae. Based on a comprehensive survey of the literature, long-term treatment strategies for children with reflux are now available.

Altered smooth muscle development and innervation in the lower genitourinary and gastrointestinal tract of the male human fetus with myelomeningocele

PURPOSE

We determine whether smooth and skeletal muscle or nerve density is altered in the lower genitourinary or gastrointestinal tract of male human fetuses with myelomeningocele at 20 weeks of gestation.

MATERIALS AND METHODS

We serially cross sectioned the lower genitourinary and gastrointestinal tracts in 7 male fetuses (mean age 20 weeks of gestation) with myelomeningocele and 4 age matched controls. Immunohistochemical staining was performed using Masson's trichrome stain and antibodies to smooth and skeletal muscle actin. S-100 protein staining for Schwann cell localization and neurofilament protein was also done. Fluorescein and rhodamine double immunolabeling was used to demonstrate the co-expression of smooth and skeletal muscle.

RESULTS

Peripheral neural innervation of the bladder, prostate and rectum was markedly decreased in myelomeningocele. Masson's trichrome and smooth muscle actin staining also demonstrated that smooth muscle was less well differentiated in myelomeningocele specimens. Scant smooth muscle was present in the myelomeningocele bladder and bladder neck with an excess of collagen in an interfascicular and intrafascicular distribution. Double immunofluorescence staining revealed persistent co-expression of smooth and skeletal muscle actin by myocytes in the myelomeningocele detrusor, while in the control bladder there was only smooth muscle expression. The skeletal muscle component of structures in fetuses with myelomeningocele, including the external sphincter, was similar to that in controls. Prostatic size, ductal morphogenesis and smooth muscle were decreased compared to those in controls.

CONCLUSIONS

A global defect exists in the development of smooth muscle in myelomeningocele in the lower genitourinary and gastrointestinal tracts by 20 weeks of gestation. Peripheral nerve density is decreased in smooth muscle in myelomeningocele, suggesting that an intact nervous system is important for the development of normal smooth muscle. Fetal surgery with coverage of the spinal cord in select cases may prevent progressive environmental injury to the somatic nervous system during the second half of gestation. However, achieving normal autonomic function is unlikely due to the extent of early global organ maldevelopment.

Free-electron laser exploiting a superlattice-like medium

Amplification in free-electron lasers exploiting media with periodically modulated refractive indices is studied in the regime of a large modulation. The conditions for realization of the large-modulation regime in a superlattice-like medium are established. The maximized gain, the corresponding saturation field and efficiency, as well as the optimal electron energy and propagation direction are determined. It is shown that the large-modulation regime makes it possible to extend significantly the operation frequency domain of the FEL employing a low-relativistic electron beam. Relationship with the Cherenkov and stimulated resonance-transition-radiation FELs is discussed. This research is partially supported by RFBR grant 97-02-17783.

Quantum control of non-circular Trojan states in hydrogen

Control of non-circular and non-spreading wave packet states by a resonant radiation field is predicted and numerically confirmed for hydrogen.

A single-system ectopic ureter draining an ectopic dysplastic kidney: delayed diagnosis in the young female with continuous urinary incontinence

OBJECTIVE

To document the array of diagnostic modalities, the variety of errant diagnoses and treatments. and the time from initial presentation to ultimate diagnosis in girls with an ectopic single-system ureter draining an ectopic hypoplastic and/or dysplastic kidney.

PATIENTS AND METHODS

Between 1990 and 1997, seven females were identified who had an ectopic hypoplastic and/or dysplastic kidney with an ectopically draining ureter, and who were treated at our institutions, either initially or upon referral. The nature and number of all diagnostic evaluations, previous diagnoses and treatments, and the time from presentation to definitive diagnosis were recorded.

RESULTS

All seven females had a classical history of successful toilet training, a normal voiding pattern and continuous urinary incontinence. Typically, a solitary kidney was noted on the initial diagnostic evaluation by ultrasonography and/or intravenous urography. The mean (range) age at initial presentation was 3.2 (2-6) years. Additionally, voiding cysto-urethrography, urodynamics, radionuclide scintigraphy, computed tomography, magnetic resonance imaging and endoscopy were performed. The age at definitive diagnosis was 3-16.5 years and the mean (range) time from initial presentation to diagnosis was 5.7 (1-10) years. Nephroureterectomy was curative and all kidneys were dysplastic.

CONCLUSION

Continuous urinary incontinence in females with a normal voiding pattern should prompt an evaluation for ureteric ectopia. When the initial evaluation yields the diagnosis of a solitary kidney, clinicians should be aware of the possibility of a hypoplastic and/or dysplastic, often ectopic, contralateral kidney with an ectopically draining ureter. Identification of this entity should allow curative surgical treatment.

Fever without apparent source on clinical examination, infectious diseases, and lower respiratory infections in children

This section focuses on issues in infectious diseases that are commonly encountered in pediatric office practice. Paul McCarthy discusses recent literature regarding the evaluation and management of acute fevers without apparent source on clinical examination in infants and children, and the evaluation of children with prolonged fevers of unknown origin. Jean Klig reviews recent literature about lower respiratory tract infection in children. Jeffrey Kahn and Eugene Shapiro discuss recent developments in pediatric infectious diseases concerning neonatal herpes infections, poliovirus immunization schedule, and group B streptococcus screening and treatment.

Office laboratory procedures, office economics, patient and parent education, and urinary tract infection

This review provides an update on four important areas in office pediatrics: office laboratory procedures, office economics, patient and parent education, and urinary tract infection. Ball reviews new information about physician office laboratories, with updates on the Clinical Laboratory Improvement Amendments, streptococcal pharyngitis, urinalyses, office stool examination, and information on Helicobacter pylori serology. Shapiro reports on office economics, highlighting new office technologies, physician operated networks, managed care, recent legislation, and the "cost versus quality" debate. Duncan provides a very thought provoking essay on parent and patient education, focusing on improving parenting skills. Wahl reviews the recent literature on urinary tract infections, with emphasis on host-bacteria interactions, diagnostic evaluations, pyelonephritis, renal cortical scarring, and long term follow-up of vesicoureteral reflux. We hope we have provided pediatricians with useful and practical information for their office practices.

Morphometric analysis of pediatric and nonhyperplastic prostate glands: evidence that BPH is not a unique stromal process

BACKGROUND

Although quantitative morphometry of benign prostatic hyperplasia (BPH) has been described, there is a paucity of information on the morphometry of the nonhyperplastic prostate. This study determines the histologic composition of prostates obtained from males, ages 2 days to 40 years, in order to provide insights into the morphometry of the "normal" gland.

METHODS

The histologic composition of 45 prostates was obtained from autopsies of males with age groups stratified to reflect the neonatal, childhood, peripubertal, adolescent, and young adult periods. Double immunoenzymatic staining and computer image analysis were used to determine the mean area densities of the smooth muscle (SM), connective tissue (CT), glandular epithelium (E), and lumen (L).

RESULTS

A progressive decrease in SM area density throughout childhood, prepuberty, and puberty was seen. The density of SM significantly increased following puberty and throughout adolescence and early adulthood. There was a concomitant increase in CT from the neonatal period throughout childhood, prepuberty, and puberty, and a decrease after puberty and throughout adolescence and early adulthood. Since the changes in SM and CT were inversely related, the percent contribution of the stromal compartment to the total gland remained constant.

CONCLUSIONS

The stromal to epithelial ratio remains constant from birth to age 40 in nonhyperplastic glands and is similar to the ratios in asymptomatic and symptomatic BPH tissues.

Menstrual bleeding in a female infant with congenital adrenal hyperplasia: altered maturation of the hypothalamic-pituitary-ovarian axis

Vaginal bleeding during the neonatal period is commonly related to the withdrawal of maternal estrogens. Vaginal bleeding has also been reported in female infants with congenital adrenal hyperplasia and has been proposed to be due to a treatment-induced activation of the hypothalamic-pituitary-ovarian axis. We report a female infant with the salt-losing form of congenital adrenal hyperplasia due to 21-hydroxylase deficiency, who had the onset of vaginal bleeding at 3 months of life. Adrenal steroid suppression had been achieved by 2.5 weeks of age. At the time of bleeding, imaging studies revealed an enlarged right ovary with a dominant 3-cm cyst and additional small cysts that had not been seen on the newborn sonogram. The uterus was enlarged and stimulated. Three weeks later (1 week after the cessation of bleeding), repeat ultrasound demonstrated a marked decrease in the size of the right ovary, and the dominant cyst was no longer seen. The patient had a heightened FSH response to GnRH and elevated levels of estradiol for age. At 5 months of age, no further episodes of sustained vaginal bleeding were observed. Repeat hormonal levels were prepubertal, and pelvic sonogram demonstrated no evidence of stimulation. The findings in our patient suggest that a decline in adrenal androgens after glucocorticoid treatment resulted in an increase in gonadotropin levels, which then triggered a transient and augmented end-organ response (menses). Further, we suggest that our infant's hormonal findings may reflect a delay in the timely development of the negative restraint by sex steroids on gonadotropins that is normally observed in infancy.

Methods to enhance in vivo urothelial growth on seromuscular colonic segments in the dog

PURPOSE

We demonstrated survival and expansion in vivo of urothelial free autografts on demucosalized seromuscular segments.

MATERIALS AND METHODS

Four methods of in vivo urothelial expansion were investigated on demucosalized colonic segments in the canine model. Group 1 underwent colonic mucosal removal by manual stripping, group 2 underwent removal of colonic mucosa and submucosa, and group 3 underwent manual stripping of the colonic mucosa followed by treatment with protamine sulfate and urea. In the 3 groups urothelial autografts were then placed on the seromuscular segment and tubularized over a balloon splint. In group 4 the colonic mucosa was removed but the grafts were not tubularized. Instead the colonic segment was sutured to the parietal peritoneum.

RESULTS

Group 4 grafts had no epithelial growth and shrinkage of the bowel segment. Group 1 grafts had minimal growth with no expansion and colonic mucosal regrowth. Group 2 grafts demonstrated growth and expansion, although these colonic segments had a significant inflammatory response and fibrosis. Group 3 grafts had the best growth and expansion with the least inflammatory response, and 1 colonic segment was almost completely covered with urothelium.

CONCLUSIONS

We demonstrated in vivo expansion of urothelial autografts grown on seromuscular colonic segments. Preservation of the submucosa is essential to prevent fibrosis of the seromuscular colonic segment and a balloon stent is crucial to prevent graft contraction. Treatment of the demucosalized segment with protamine sulfate and urea results in better urothelial expansion and less colonic mucosal regrowth.

Scrotal cystic lymphangioma: the misdiagnosed scrotal mass

PURPOSE

We report 7 cases of scrotal cystic lymphangioma and review the literature on this unusual lesion, which is often misdiagnosed as other conditions and treated incorrectly.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 7 patients with scrotal cystic lymphangioma treated from 1984 to 1996 at 5 institutions.

RESULTS

Mean patient age at presentation was 3 years and painless scrotal swelling was the most common symptom. Physical examination demonstrated an unusual cystic scrotal mass with a normal testis and cord in most patients, and ultrasound in 4 showed a complex septated cystic mass. Preoperative misdiagnosis in all 7 patients included hernia, hydrocele, hematocele, varicocele and possible torsion. In 6 children the lesions were more extensive than expected with deep perineal and/or inguinal involvement, including 2 who also had pelvic and retroperitoneal extension. Incomplete excision led to recurrence in 4 patients.

CONCLUSIONS

Scrotal cystic lymphangioma presents as an unusual cystic scrotal mass. Although misdiagnosis has been common, awareness of the characteristic features of this lesion should lead to the correct preoperative diagnosis. When lymphangioma is suspected, imaging of the adjacent inguinal, perineal and pelvic regions should be performed. Complete excision is mandatory to prevent recurrence.

Evaluation of the effect of endothelin-1 and characterization of the selective endothelin a receptor antagonist PD155080 in the prostate

PURPOSE

To evaluate the contractile effect of endothelin-1 (ET-1) on prostatic urethral pressure and to characterize the effect of the selective ETA receptor antagonist PD155080 on ET-1 mediated prostatic urethral pressure.

MATERIALS AND METHODS

The effect of intravenous ET-1 administration on canine urethral pressure was determined in the presence and absence of PD155080. The affinity of PD155080 for endothelin-mediated contraction was determined using antagonist dissociation studies. Saturation and competition binding studies were performed using [125I] ET-1 in both human and canine prostate.

RESULTS

ET-1 bolus injection elicited shallow and prolonged increases the prostatic urethral pressure. Pretreatment with PD155080 totally abolished the urethral contractile response to ET-1. Specific [125I] ET-1 binding was saturable and of high affinity. Two ET receptor subtypes (ETA receptor, ETB receptor) have been identified in human prostate. The ratio of ETA to ETB receptors was approximately 1.5:1 in both human and canine prostates. Isometric tension studies revealed that PD155080 shifted the ET-1 dose-response curves to the right and exhibited no effect on the ETB receptor selective agonist sarafotoxin dose-response curves.

CONCLUSION

ET-1 mediates prostate smooth muscle tone and may play a role in the pathophysiology and treatment of benign prostatic hyperplasia (BPH).

Endothelins in canine genitourinary tissues

PURPOSE

To characterize the functional effect of endothelin-1 (ET1) and endothelin-3 (ET3), immunohistochemically localize ET1-like immunoreactivity, and measure the tissue levels of immunoreactive endothelin (irET) in canine genitourinary (GU) tissues.

MATERIALS AND METHODS

Canine GU tissues were characterized by measuring ET1 levels using a RIA, immunohistochemical staining of ET1 and isometric tension studies.

RESULTS

Immunoreactive endothelin was present, to varying degrees, in the vas deferens, ureter, prostate, bladder and urethra. Functionally, ET1 demonstrated the typical concentration response characteristics in the canine bladder base, bladder body, and prostate. The maximal tension (Emax) measured following ET1 challenge was approximately 20-fold greater in the bladder body (0.67 +/- 0.21 g/mm.2) and bladder base (0.48 +/- 0.18 g/mm.2) as compared to the prostate 0.04 +/- 0.001 g/mm.2 The Emax of ET3 in the bladder body (0.31 +/- 0.12 g/mm.2) and bladder base (0.19 +/- 0.08 g/mm.2) was significantly lower than the corresponding Emax of ET1. No measurable contractile response was elicited by ET3 in the canine prostate. Immunohistochemical staining localized the ET-like immunoreactivity to the glandular epithelium of the prostate and the transitional epithelium of the bladder.

CONCLUSIONS

Endothelins are ubiquitous in the canine lower GU tract with predominant localization to the epithelial elements. Endothelins are also functionally active in canine GU tissues, but the specific role of endothelins in the physiology and pathophysiology of GU tissues requires further investigation.

Smooth muscle development in the obstructed fetal bladder

OBJECTIVES

To evaluate changes in the smooth muscle and connective tissue development in the obstructed and normal fetal bladder.

METHODS

The smooth muscle and connective tissue composition of 19 fetal urinary bladders, including those of 9 fetuses with anatomic obstruction and 10 controls free of urologic disease, were analyzed by light microscopy and computer-assisted color image analysis.

RESULTS

The bladder wall thickness was markedly increased in obstructed fetuses throughout gestation as compared with that in controls. The disparity in bladder wall thickness increased rapidly during gestation. The percent area density of smooth muscle and connective tissue as well as the ratio of smooth muscle to connective tissue remained the same in the obstructed and normal control fetal bladders.

CONCLUSIONS

Although bladder outlet obstruction is associated with a marked increase in bladder wall thickness, the percent of smooth muscle and connective tissue comprising the mural histology remains relatively constant as compared with that of normal fetal controls. This study suggests that bladder outlet obstruction in the fetus is not associated with excess collagen deposition but rather with an increased amount of bladder with normal cellular content and a concomitant increase in smooth muscle development.

Comparative, in vitro, studies of hippocampal tissue from homing and non-homing pigeon

The purpose of this research was to characterize morphologically and electrophysiologically tissue slices obtained from the hippocampus of homing and non-homing pigeons. When hippocampal slices from the brain of homing and non-homing pigeons are observed under the dissecting microscope, diffuse fiber paths can be seen. These fiber pathways appeared to be identical with the medial fiber tract (VM) previously described histologically in the hippocampus of homing pigeon. Visualization of these tracts in living slices allowed placement of stimulating and recording electrodes in corresponding locations in these slices in both homing and non-homing pigeons. Extracellular potentials recorded from VM regions of the brains of both homing and non-homing pigeons were sensitive to CNQX indicating that glutamate may be a neurotransmitter in this area of pigeon hippocampus. These potentials could undergo long-term potentiation (LTP) following high frequency stimulation. This LTP was blocked by NMDA receptor antagonist APV in the hippocampus of homing pigeon, but was APV-resistant in the hippocampus of non-homing pigeon. Extracellular potentials from the hippocampus of homing pigeons were increased in amplitude when slices were perfused with Mg(2+)-free Ringer, while potential recorded from hippocampal slices from non-homing pigeons wre unaffected by Mg(2+)-free solutions. Intracellular recordings from the hippocampal slices of homing pigeons revealed that about half the cells demonstrated excitatory synaptic potentials evoked by extracellular stimulation. The EPSP was sometimes large enough to trigger an action potential. Neurons filled with the fluorescent dye, Lucifer Yellow, in the hippocampus of homing pigeons showed multipolar structure. The response of these cells to extracellular stimulation provides the activity responsible for the extracellular potentials which can undergo LTP.

Comparison of the cellular composition of benign prostatic hyperplasia in Chinese and Caucasian-American men

OBJECTIVES

To compare the cellular composition of benign prostatic hyperplasia (BPH) in Chinese and Caucasian-American men.

METHODS

Surgical specimens of the prostate were obtained from 9 Chinese and 8 Caucasian-American men undergoing cystoprostatectomy for invasive transitional cell carcinoma. The mean ages of the Chinese and Caucasian-American men were 66.8 years and 66.4 years, respectively (P = 0.94). The mean prostate weight of the Chinese and Caucasian-American men was 53.4 g and 32.1 g, respectively (P = 0.01). Double immunoenzymatic staining with antibodies against actin and prostatic acid phosphatase and computer-assisted color image analysis were performed on whole-mount tissue sections. The percent area density of smooth muscle (SM), connective tissue (CT), epithelium (E), and epithelial lumen (L) were obtained by analyzing 30 fields from each specimen.

RESULTS

The mean percent area density of SM, CT, E, and L in the prostate of Chinese men was 32%, 9.1%, 10.8%, and 48.5%, respectively. The mean percent area density of SM, CT, E, and L in the prostate of Caucasian-American men was 52.5%, 27.9%, 12.8%, and 7%, respectively. Overall, the prostates of Chinese men contained significantly more glandular lumen and significantly less SM and CT.

CONCLUSIONS

The present study demonstrates that the cellular composition of BPH in the prostates of Caucasian-American and Chinese men is different. These cellular differences may account for previously observed differences in the incidence of clinical BPH.

Proton MR spectroscopy of childhood adrenoleukodystrophy

PURPOSE

To determine the potential of proton MR spectroscopy to monitor patients with childhood-onset cerebral adrenoleukodystrophy (COCALD).

METHODS

Single-voxel MR spectroscopy was performed in 16 children with COCALD (24 examinations) who had had no treatment and in 7 children (13 examinations) who had had bone marrow transplantation.

RESULTS

In the untreated children with clinically active COCALD, the metabolite ratios N-acetyl-aspartate (NAA)/creatine (Cr) and NAA/choline (Ch) were decreased while Ch/Cr was increased. This trend agrees well with those reported by other researchers, although different experimental sequences and parameters were used in our study. Comparison of these ratios with those from a control group yielded significant differences in the occipital region. In the children who were clinically stable after bone marrow transplantation, the mean levels of the three ratios were between those of the control subjects and the patients with untreated COCALD: the differences in these ratios approached significance. In patients who had been monitored periodically, MR spectroscopy metabolite ratios correlated well with the dementia rating score, reflecting clinical status.

CONCLUSION

There is good correlation between MR spectroscopy metabolite ratios and a patient's clinical status. MR spectroscopy appears to be a useful, noninvasive tool to monitor patients with adrenoleukodystrophy, and it increases the overall sensitivity of MR techniques in clinical applications.

Localization of the alpha 1A-adrenoceptor in the human prostate

PURPOSE

We determined the tissue localization of the alpha 1a-adrenoceptor in the human prostate.

MATERIALS AND METHODS

Autoradiographic localization of the alpha 1a-adrenoceptor in the human prostate was determined by performing competitive displacement experiments on slide mounted tissue sections using the ligand 125iodine-2-(-[4-hydroxyphenyl]-ethyl-aminomethyl)tetralone (125I-Heat), and the alpha 1-antagonists WB-4101 (4 x 10(-8) M.) and 5-carboxamido-2,6-diethyl-1,4-dihydro-3-[N-(3-[4-hydroxy-4-phenylpipe ridin- yl]propyl)]carboxamido-4-(4-nitrophenyl) (SNAP 5272, 3 x 10(-7) M.). Under these experimental conditions, WB-4101 and SNAP 5272 are selective alpha 1a/alpha 1d-adrenoceptor and alpha 1a-adrenoceptor antagonists, respectively. The autoradiographs were quantitatively analyzed using a computer image analysis system.

RESULTS

Specific 125I-Heat binding associated with the epithelium and stroma were independently analyzed. WB-4101 and SNAP 5272 inhibited 100% of the specific 125I-Heat binding in the stroma, suggesting that all of the stromal alpha 1-adrenoceptors are of the alpha 1a subtype. WB-4101 inhibited none of the specific 125I-Heat binding in the epithelium, suggesting that the alpha 1-adrenoceptor in the epithelium is of the alpha 1b subtype. SNAP 5272 displaced only 25% of the specific 125I-Heat binding in the epithelium, suggesting that a relatively small percentage of the epithelial alpha 1-adrenoceptor is of the alpha 1a subtype.

CONCLUSIONS

To our knowledge, our study represents the first cellular localization of the alpha 1-adrenoceptor subtypes in the human prostate using highly selective alpha 1-adrenoceptor antagonists and is consistent with the physiological observation that the activity of prostatic smooth muscle is mediated by the alpha 1a-adrenoceptor.

Using the information system to assess change: the impact of downsizing the acute sector

A population-based approach was used to monitor impact of hospital bed closures in Winnipeg, Manitoba. Four years of administrative data were analyzed. Access to hospital services was not adversely affected: The reduction in beds resulted in increases in outpatient surgery and earlier discharges. In addition, access favored the admission of persons with more health care needs. Quality of care, as measured by mortality within 3 months of admission, readmission rates within 30 days of discharge, and increased contact with physicians within 30 days of discharge, did not change. The health status of the Winnipeg population, measured by premature mortality, did not change. However, health status and hospital use was found to be strongly related to socioeconomic status. In light of this gradient, the authors conclude that well designed and evaluated experiments that focus on the determinants of health, rather than on providing more health care services, could help identify ways of reducing hospital use.

Interleukin-1 mediates increased plasma levels of eicosanoids and cytokines in patients with sepsis syndrome

The purpose of this was to study evaluate the effects of interleukin-1 (IL-1) inhibition by human recombinant IL-1 receptor antagonist (IL-1ra) on plasma prostaglandin, leukotriene, and cytokine levels in sepsis syndrome. As part of a multisite, prospective, randomized, double-blind, placebo-controlled clinical trial, 19 septic patients received IL-1ra in a 100 mg bolus followed by 2.0 mg/kg/h i.v. for 72 h (n = 10) or placebo (n = 9). Plasma thromboxane B2 (TXB2), prostaglandin 6-keto-F1 alpha (PGI), leukotriene B4 (LTB4), leukotrienes C4D4E4 (LTC4D4E4), IL-1 beta, IL-6, and tumor necrosis factor alpha (TNF) were measured by ELISA before study drug infusion (baseline) and at 24, 48, 72, and 96 h after the beginning of the study drug infusion. Differences between placebo and IL-1-ra for plasma LTB4 and TNF were not significant. Plasma TXB2, PGI, LTC4D4E4, and IL-6, expressed as % baseline, were significantly lower in patients receiving IL-1ra than in the placebo group (p < .05), while plasma IL-1 was increased significantly. IL-1 may be a necessary mediator of increased circulating PGI, TXB2, LTC4D4E4, and IL-6 levels in patients with sepsis syndrome. Plasma IL-1 is increased with infusion of IL-1ra. The clinical significance of IL-1 in modifying circulating eicosanoid and cytokine concentrations in clinical sepsis is not clear from the data.

Noninvasive measurement of tissue magnesium and correlation with cardiac levels

BACKGROUND

Intracellular magnesium ([Mg]i) plays an important role in the regulation of myocardial metabolism, contractility, and the maintenance of transsarcolemmal and intracellular ionic gradients. An understanding of the role of magnesium in the clinical setting, however, is hampered by the lack of an assay of intracellular tissue magnesium levels.

METHODS AND RESULTS

We used energy-dispersive x-ray analysis to measure [Mg]i in sublingual epithelial cells and to correlate the level with those in atrial biopsy specimens from the same patients during cardiopulmonary bypass. Levels were also measured in acute myocardial infarction (AMI) patients before and after intravenous magnesium sulfate administration and compared with those from intensive care unit (ICU) patients and healthy individuals. A strong correlation between sublingual epithelial cell (mean, 32.1 +/- 0.3 mEq/L) and atrial tissue (mean, 32.1 +/- 0.3 mEq/L) [Mg]i was present in 18 cardiac surgery patients (r = .68, P < .002). Epithelial and atrial [Mg]i levels were lower than in healthy individuals (33.7 +/- 0.5 mEq/L, P < .01) studied at that time and correlated poorly with serum magnesium. Mean [Mg]i in 22 AMI patients was 30.7 +/- 0.4 mEq/L, which was significantly lower than in 21 ICU patients and 15 healthy individuals (35.0 +/- 0.5 mEq/L and 34.5 +/- 0.7 mEq/L, respectively, P < .001). Intravenous magnesium sulfate was administered to most of the AMI patients (mean dose, 36 +/- 6 mmol). [Mg]i rose significantly in the AMI patients over the first 24 hours, and the magnitude of the increase was greater in those who received higher doses of intravenous magnesium sulfate.

CONCLUSIONS

Sublingual epithelial cell [Mg]i correlates well with atrial [Mg]i but not with serum magnesium. [Mg]i levels are low in patients undergoing cardiac surgery and those with AMI. Intravenous magnesium sulfate corrects low [Mg]i levels in AMI patients. Energy-dispersive x-ray analysis determination of sublingual cell [Mg]i may expedite the investigation of the role of magnesium deficiency in heart disease.