Autoantibodies to fibrillin 1 in systemic sclerosis: ethnic differences in antigen recognition and lack of correlation with specific clinical features or HLA alleles

OBJECTIVE

We previously reported the presence of autoantibodies to the extracellular matrix protein, fibrillin 1, in sera from patients with systemic sclerosis (SSc). These autoantibodies appeared to be highly disease-specific but had significantly different frequencies among ethnic groups. The aims of this study were 3-fold: 1) to determine whether sera from SSc patients of different ethnic backgrounds recognized different antigenic epitopes of fibrillin 1, 2) to determine whether sera from patients with polymyositis/dermatomyositis (PM/DM) with or without interstitial lung disease (ILD) also produced these antibodies, and 3) to determine any correlation of anti-fibrillin 1 antibodies with specific clinical features of SSc, other autoantibodies, or HLA class II alleles in a prospectively studied cohort of SSc patients with early (<5 years' duration) disease (the Genetics versus Environment In Scleroderma Outcome Study [GENISOS] cohort).

METHODS

Three recombinant peptides accounting for the N-terminal end, proline-rich C region, and epidermal growth factor-like calcium-binding (EGF-cb) domains of fibrillin 1 were used in a radioimmunoassay to screen sera from a large group of SSc and PM/DM patients and ethnically matched controls.

RESULTS

The majority of Choctaw American Indians, Japanese, and African Americans with SSc produced IgM and/or IgG autoantibodies to one or more recombinant fibrillin 1 proteins, while <50% of Caucasians with SSc showed seroreactivity. There were striking ethnic differences in fibrillin 1 antigenic epitope recognition among these ethnic groups. African American SSc sera recognized primarily the N-terminal end, and Caucasian sera mostly recognized the EGF-cb repeats and the proline-rich C region. In contrast, most Choctaw American Indian and Japanese SSc sera appeared to recognize 2 or 3 epitopes, respectively. PM/DM patient sera did not recognize any of the fibrillin 1 epitopes regardless of the presence of ILD. In the prospective, multiethnic GENISOS cohort, the presence of anti-fibrillin 1 antibodies did not correlate with any major clinical manifestations, other autoantibodies, or HLA class II alleles.

CONCLUSION

There are striking ethnic differences in antigenic epitope specificity of anti-fibrillin 1 antibodies in patients with SSc, and the majority of SSc patients, except for Caucasians, produce antibodies to fibrillin 1. The antifibrillin response thus far remains specific for scleroderma syndromes, but it does not correlate with any major clinical features, other autoantibodies, or HLA class II alleles.

Comprehensive follow-up care and life-threatening illnesses among high-risk infants: A randomized controlled trial

CONTEXT

Inner-city high-risk infants often receive limited and fragmented care, a problem that may increase serious illness.

OBJECTIVE

To assess whether access to comprehensive care in a follow-up clinic is cost-effective in reducing life-threatening illnesses among high-risk, inner-city infants.

DESIGN

Randomized controlled trial.

SETTING AND PARTICIPANTS

A total of 887 very-low-birth-weight infants born in a Texas county hospital between January 1988 and March 1996 and followed up in a children's hospital clinic. One hundred four infants who became ineligible or died after randomization but before nursery discharge were excluded from the analysis.

INTERVENTIONS

Infants were randomly assigned to receive routine follow-up care (well-baby care and care for chronic illnesses; n = 441) or comprehensive care (which included the components of routine care plus care for acute illnesses, with 24-hour access to a primary caregiver; n = 446).

MAIN OUTCOME MEASURES

Life-threatening illnesses (ie, causing death or hospital admission for pediatric intensive care) occurring between nursery discharge and age 1 year, assessed by blinded evaluators from inpatient charts and state Medicaid and vital statistics records; and hospital costs (estimated from department-specific cost-to-charge ratios).

RESULTS

Comprehensive care resulted in a mean of 3.1 more clinic visits and 6.7 more telephone conversations with clinic staff (P<.001 for both). One-year outcomes were unknown for fewer comprehensive-care infants than routine-care infants (9 vs 28; P =.001). Identified deaths were similar (11 in comprehensive care vs 13 in routine care; P =.68). The comprehensive-care group had 48% fewer life-threatening illnesses (33 vs 63; P<.001), 57% fewer intensive care admissions (23 vs 53; P =.003), and 42% fewer intensive care days (254 vs 440; P =.003). Comprehensive care did not increase the mean estimated cost per infant for all care ($6265 with comprehensive care and $9913 with routine care).

CONCLUSION

Comprehensive follow-up care by experienced caregivers can be highly effective in reducing life-threatening illness without increasing costs among high-risk inner-city infants. JAMA. 2000;284:2070-2076.

Platelet Pl(A2) allele and incidence of coronary heart disease: results from the Atherosclerosis Risk In Communities (ARIC) Study

BACKGROUND

The major platelet integrin glycoprotein IIb-IIIa plays a primary role in platelet aggregation and acute thrombus formation at the site of vascular injury. A genetic polymorphism of glycoprotein IIb-IIIa (Pl(A)) has recently been proposed as a potential genetic factor linking to platelet hyperaggregability and increased risk of myocardial infarction. Despite numerous, mostly nonprospective studies, the role of this polymorphism as a clinically relevant, inherited risk factor for coronary heart disease (CHD) is still controversial. The purpose of this study was to determine whether Pl(A2) is a risk factor for incident CHD and whether it is correlated with increased platelet activation in a case-cohort study nested within a prospective epidemiologic investigation.

METHODS AND RESULTS

Blood samples were collected and processed from the Atherosclerosis Risk in Communities Study cohort at the baseline examination (1987 to 1989). They were stored at -80 degrees C. Pl(A1/A2) genotype and plasma beta-thromboglobulin levels were determined in 439 incident CHD cases and a reference cohort sample of 544 (of whom 18 were also CHD cases). The prevalence of the Pl(A2) allele was not different in cases versus noncases. No significant correlation between CHD risk factors and the Pl(A2) allele was noted either. Platelet activation, as measured by plasma beta-thromboglobulin levels, was not enhanced in individuals with the Pl(A2) allele.

CONCLUSIONS

This prospective study indicates that healthy individuals carrying the Pl(A2) allele do not have an increased risk of CHD.

Evaluation of renal tubular functions in convalescent phase of hemorrhagic fever with renal syndrome

To evaluate renal tubular functions and to investigate the causative factors of urinary-concentrating defects in the late stage of hemorrhagic fever with renal syndrome (HFRS), 11 HFRS patients in the convalescent phase were studied and compared with 8 acute renal failure (ARF) patients in convalescence (disease controls) and 9 healthy adults preparing for kidney donation (normal controls, NC). Minimal urine osmolality induced by water loading was higher (p < 0.05) in HFRS (89.5 +/- 22.1 mosm/kg) and ARF patients (84.8 +/- 14.7 mosm/ kg) than in NC (47.8 +/- 4.6 mosm/kg), but the solute-free water clearance of HFRS patients (9.0 +/- 1.3%), measured at maximal diuresis, was not different from that of ARF patients (6.7 +/- 1.2%) or NC (10.5 +/- 1.4%). After 12-hour water deprivation + vasopressin stimulation, HFRS had lower urine osmolality (433.7 +/- 31.1 versus 850.0 +/- 35.1 mosm/kg; p < 0.05), urine-to-plasma osmolality ratio (1.47 +/- 0.11 versus 2.91 +/- 0.11; p < 0.05), and solute-free water reabsorption (0.53 +/- 0.07 versus 0.91 +/- 0.12%; p < 0.05) than NC. As compared with ARF patients (1.09 +/- 0.16%) or NC (1.49 +/- 0.16%), HFRS patients (0.43 +/- 0.20%) had lower solute-free water reabsorption measured at maximal antidiuresis induced by water deprivation + vasopressin stimulation + hypertonic saline infusion (p < 0.05). In HFRS, the plasma vasopressin level and plasma vasopressin/osmolality ratio increased from 3.9 +/- 0.8 to 6.1 +/- 1.1 pg/ml and from 0.013 +/- 0.003 to 0.020 +/- 0.004 pg/ml/mosm/kg after 12-hour water deprivation, respectively (p < 0.01). However, neither basal nor stimulated values of the plasma vasopressin level or plasma vasopressin/osmolality ratio was different among the 3 groups. HFRS patients were not different from ARF patients or NC in lithium clearance, urinary-acidifying capacity, and fractional excretions of sodium, potassium and bicarbonate. We conclude that in the convalescent phase of HFRS, the urinary-acidifying ability is not disturbed, the urinary-diluting defect is mild, and the urinary-concentrating capacity is obviously impaired. This study suggests that the most important factor contributing to the urinary-concentrating defect in HFRS is the reduced collecting duct responsiveness to vasopressin.

Thirteen novel mutations of the replicated region of PKD1 in an Asian population

BACKGROUND

Mutations of PKD1 are thought to account for approximately 85% of all mutations in autosomal dominant polycystic kidney disease (ADPKD). The search for PKD1 mutations has been hindered by both its large size and complicated genomic structure. To date, few mutations that affect the replicated segment of PKD1 have been described, and virtually all have been reported in Caucasian patients.

METHODS

In the present study, we have used a long-range polymerase chain reaction (PCR)-based strategy previously developed by our laboratory to analyze exons in the replicated region of PKD1 in a population of 41 unrelated Thai and 6 unrelated Korean families with ADPKD. We have amplified approximately 3.5 and approximately 5 kb PKD1 gene-specific fragments (5'MR and 5'LR) containing exons 13 to 15 and 15 to 21 and performed single-stand conformation analysis (SSCA) on nested PCR products.

RESULTS

Nine novel pathogenic mutations were detected, including six nonsense and three frameshift mutations. One of the deletions was shown to be a de novo mutation. Four potentially pathogenic variants, including one 3 bp insertion and three missense mutations, were also discovered. Two of the nonconservative amino acid substitutions were predicted to disrupt the three-dimensional structure of the PKD repeats. In addition, six polymorphisms, including two missense and four silent nucleotide substitutions, were identified. Approximately 25% of both the pathogenic and normal variants were found to be present in at least one of the homologous loci.

CONCLUSION

To our knowledge, this is the first report of mutation analysis of the replicated region of PKD1 in a non-Caucasian population. The methods used in this study are widely applicable and can be used to characterize PKD1 in a number of ethnic groups using DNA samples prepared using standard techniques. Our data suggest that gene conversion may play a significant role in producing variability of the PKD1 sequence in this population. The identification of additional mutations will help guide the study of polycystin-1 and better help us to understand the pathophysiology of this common disease.

Effect of high or low frequency electroacupuncture on the cellular activity of catecholaminergic neurons in the brain stem

Although the opioid system plays a pivotal role in the analgesic effect of electroacupuncture (EA), it has been suggested that other peptidergic systems also may be involved in the therapeutic effect of EA. Among several peptides for EA-induced analgesia, catecholamine (CA) is associated with the descending pain inhibitory system. We evaluated whether the different frequencies of EA modified the cellular activity of central CA synthesizing neurons using double labeling immunohistochemistry between Fos-like immunoreactive (FLI) neurons and dopamine-beta-hydroxylase (DBH)/tyrosine hydroxylase (TH)-positive neurons. We observed that different frequencies of EA increased the number of FLI neurons in catecholaminergic neurons, such as the dorsal raphe (DR), hypothalamic arcuate nucleus (Arc), locus coeruleus (LC), A5 noradrenaline cells (A5), and A7 noradrenaline cells (A7). In addition, different frequencies of EA significantly increased the ratio of colocalization between FLI neurons and TH positive neurons in DR, LC and Arc. Only low frequency EA increased the neuronal activity in Arc. The ratio of double labeling between FLI and DBH positive neurons was also elevated at both LC and A5. These data demonstrate that different frequencies of EA increase the cellular activity of central CA synthesizing neurons, suggesting that the CA system plays an important role in EA-induced analgesia.

Increased plasma homocysteine is an independent predictor of new atherothrombotic brain infarction in older persons

A prospective study investigated the association of plasma homocysteine and other risk factors with the incidence of atherothrombotic brain infarction (ABI) at 31 +/- 9 month follow-up in 153 men and 347 women (mean age 81 +/- 9 years, median age 82). The stepwise Cox regression model showed that significant independent predictors of new ABI in older persons were age (risk ratio 1.060 for each 1-year increase of age), plasma homocysteine (risk ratio 1.079 for each 1 micromol/L increase), prior ABI infarction (risk ratio 3.282), current cigarette smoking (risk ratio 2.687), hypertension (risk ratio 2.965), and diabetes mellitus (risk ratio 2.015).

Aortic sinotubular atherosclerotic debris associated with cerebral embolic events can be identified by transthoracic echocardiography

OBJECTIVE

To evaluate the association between the presence of aortic sinotubular debris (STAD) identified by transthoracic echocardiography (TTE) and embolic strokes.

BACKGROUND

The presence of atherosclerotic debris in the ascending aorta or aortic arch detected by transesophageal echocardiography or epiaortic echocardiography has been well established to be correlated with embolic stroke or other thromboembolic events. No data are available on the role of TTE in describing aortic pathology in thromboembolic events.

METHODS

We identified 60 transthoracic echocardiographic studies from 11,275 studies, in which STAD was diagnosed. The charts of these patients (group 1; mean age 67 +/- 10 years) were reviewed and compared with those of 57 patients (group 2) without STAD, matched for age, gender and risk factors for advanced atherosclerosis. The results of brain imaging procedures, carotid duplex and coronary angiography were also reviewed.

RESULTS

Ischemic stroke was found in 15 of group 1 (25%) and 4 patients of group 2 (7%, odds ratio = 4.4; 95% confidence interval, 1.3-19.4, p = 0.008). The average thickness of STAD was 0.7 +/- 0.2 cm in stroke patients and 0.6 +/- 0.2 cm in patients without stroke (p = n.s.). STAD was associated with </=40% carotid artery stenosis.

CONCLUSION

STAD detected by TTE is strongly associated with embolic strokes. Our findings expand the role of TTE in the evaluation of patients with embolic strokes.

Increased plasma homocysteine is an independent predictor of new coronary events in older persons

A prospective study investigated the association of plasma homocysteine and other risk factors with the incidence of new coronary events at 31 +/- 9 month follow-up in 153 men and 347 women, mean age 81 +/- 9 years. The stepwise Cox regression model showed that significant independent predictors of new coronary events in older persons were age (risk ratio 1.041), plasma homocysteine (risk ratio 1.073), current cigarette smoking (risk ratio 2.524), hypertension (risk ratio 2.032), diabetes mellitus (risk ratio 2.022), serum total cholesterol (risk ratio 1.013), serum high-density lipoprotein cholesterol (risk ratio 0.925), and serum triglycerides (risk ratio 1.004).

Risk factors for coronary artery disease in old persons in an academic hospital-based geriatrics practice

BACKGROUND

Risk factors for coronary artery disease (CAD) in old men and women include age, cigarette smoking, hypertension, diabetes mellitus, dyslipidemia, and obesity.

OBJECTIVE

To investigate the association of risk factors with prevalence of CAD.

METHODS

We performed a retrospective analysis of charts for all old persons seen during the period from 1 January 1998 through 15 June 1999 at an academic hospital-based geriatric practice to investigate associations of risk factors with prevalence of CAD among old persons. We studied 467 men, mean age 80 +/- 8 years, and 1444 women, mean age 81 +/- 8 years.

RESULTS

CAD was present in 201 of 467 men (43%) and in 473 of 1444 women (33%; P < 0.0001). Risk factors for CAD according to univariate analysis were age (P < 0.0001 for women), cigarette smoking (P < 0.0001 for men and women), hypertension (P < 0.0001 for men and women), diabetes mellitus (P < 0.0001 for men and women), obesity (P < 0.0001 for men and women), and serum levels of total cholesterol (P < 0.0001 for men and P = 0.0001 for women), low-density lipoprotein (LDL) cholesterol (P < 0.0001 for men and P = 0.001 for women), and high-density lipoprotein (HDL) cholesterol (inverse association; P = 0.0001 for men and women). Stepwise logistic regression analysis showed that significant independent risk factors for CAD were cigarette smoking (odds ratio 6.7 for men), hypertension (odds ratios 3.3 for men and 2.7 for women), and serum levels of HDL cholesterol (odds ratio 0.83 for men and women) and LDL cholesterol (odds ratios 1.10 for men and 1.09 for women).

CONCLUSIONS

Significant independent risk associations with prevalence of CAD among old persons were found for cigarette smoking by men, hypertension in men and women, and serum levels of HDL cholesterol (inverse association) in men and women, and of LDL cholesterol in men and women.

Secondary polycythemia associated with idiopathic membranous nephropathy

A 58-year-old male patient had secondary polycythemia associated with idiopathic nephrotic syndrome. The renal biopsy revealed membranous nephropathy, and the bone marrow biopsy disclosed hypercellular marrow with mild panhyperplasia. The concentration of serum erythropoietin was 8.5 mU/ml. The erythrocytosis was characterized by an increased red cell volume (40.2 ml/kg) and normal arterial oxygen saturation. There were no associated lesions that could induce secondary polycythemia, except the biopsy-proven membranous nephropathy. He was treated with prednisolone and cyclophosphamide, and the nephrotic syndrome was partially remitted after 6 weeks. With partial remission of nephrotic syndrome, the erythrocytosis was resolved. This case illustrates the rarely reported association of the nephrotic syndrome and erythrocytosis, and the resolution of erythrocytosis with improvement of nephrotic syndrome.

Comparison of visual results in initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism

PURPOSE

To report the results of initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism.

METHODS

A total of 1161 consecutive inital and retreatment laser in situ keratomileusis procedures in 697 patients performed between September 19, 1996, and June 20, 1998, were retrospectively analyzed. Baseline and postoperative best spectacle-corrected visual acuity, uncorrected visual acuity, spherical and cylindrical refractions, computerized video keratography, and biomicroscopy were measured or performed on each eye.

RESULTS

Of 1,071 eyes, 900 (84%) underwent a single-laser in situ keratomileusis procedure, and 171 of 1,071 eyes (16%) underwent one or two re-treatment procedures. The preoperative mean +/- SD spherical equivalent was -5.09 +/- 3.15 diopters (range, -0.75 to -14.38 diopters) and the cylinder was 0.97 +/- 1.09 diopters (range, 0.00 to 3.25 diopters) in the group that underwent a single laser in situ keratomileusis treatment. The preoperative mean +/- SD spherical equivalent was -6.26 +/- 3.04 diopters (range, -1.75 to -12.88 diopters) and the cylinder was 1.53 +/- 1.11 diopters (range, 0.00 to 3.50 diopters) in the group that underwent re-treatment. Before re-treatment, 110 eyes (64.3%) in the group that underwent re-treatment achieved 20/40 or better uncorrected visual acuity and 23 eyes (13.5%) achieved 20/25 or better. Three months after re-treatment, 155 eyes (90.6%) achieved 20/40 or better, and 80 eyes (46.8%) achieved 20/25 or better. In the single-procedure group, uncorrected visual acuity at 3 months revealed 20/40 vision or better in 856 eyes (95.1%) and 20/25 vision or better in 572 eyes (63.6%). In this study group, 23.6% of eyes with a preoperative spherical equivalent greater than -6.0 diopters underwent re-treatment compared with 11.8% of eyes with a preoperative spherical equivalent of -6.0 diopters or less.

CONCLUSIONS

Laser in situ keratomileusis appears to be an effective procedure for mild, moderate, and severe myopia. In eyes with residual refractive error, re-treatment laser in situ keratomileusis procedures can result in good visual outcomes.

Electrochemical treatment of mouse and rat fibrosarcomas with direct current

Electrochemical treatment (ECT) of cancer utilizes direct current to produce chemical changes in tumors. ECT has been suggested as an effective alternative local cancer therapy. However, a methodology is not established, and mechanisms are not well studied. In vivo studies were conducted to evaluate the effectiveness of ECT on animal tumor models. Radiation-induced fibrosarcomas were implanted subcutaneously in 157 female C3H/HeJ mice. Larger rat fibrosarcomas were implanted on 34 female Fisher 344 rats. When the spheroidal tumors reached 10 mm in the mice, two to five platinum electrodes were inserted into the tumors at various spacings and orientations. Ten rats in a pilot group were treated when their ellipsoidal tumors were about 25 mm long; electrode insertion was similar to the later part of the mouse study, i.e., two at the base and two at the center. A second group of 24 rats was treated with six or seven electrodes when their tumors were about 20 mm long; all electrodes were inserted at the tumor base. Of the 24 rats, 12 of these were treated once, 10 were treated twice. and 2 were treated thrice. All treated tumors showed necrosis and regression for both mice and rats; however, later tumor recurrence reduced long-term survival. When multiple treatments were implemented, the best 3 month mouse tumor cure rate was 59.3%, and the best 6 month rat tumor cure rate was 75.0%. These preliminary results indicate that ECT is effective on the radiation-induced fibrosarcoma (RIF-1) mouse tumor and rat fibrosarcoma. The effectiveness is dependent on electrode placement and dosage.

Issues in use of SAS PROC.MIXED to test the significance of treatment effects in controlled clinical trials

A project that originated with the aim of documenting the implications of dropouts for tests of significance based on general linear mixed model procedures resulted in recognition of problems in the use of SAS PROC.MIXED for this purpose. In responding to suggestions and criticisms, we have further analyzed simulated clinical trial data with realistic autoregressive structure, using alternative error model formulations, different approaches to the use of covariates to model dropout patterns, and different ways to include the critical time variable in the mixed model. Results emphasize the sensitivity of the PROC.MIXED tests of significance for GROUP and TIME x GROUP equal slopes hypothesis to less than optimal modeling of the error covariance structure. Even with the authoritatively recommended best available modeling of the error structure, model formulations that made use of the REPEATED statement did not maintain conservative test sizes when covariates were required to model dropout data patterns. Random coefficients models that employed the RANDOM statement did permit appropriate covariate controls, but the tests of significance for treatment effects were lacking in power. After examining a variety of alternative PROC.MIXED model formulations, it is concluded that none provided both Type I error protection and power comparable to that of simple two-stage analysis of covariance (ANCOVA) procedures for confirming the presence of true treatment effects in controlled clinical trials. Other issues examined in this article concern treating baseline scores as both covariate and initial repeated measurement to which a linear means model is fitted, failure to take advantage of the regression of repeated measurements on time in modeling time as an unordered categorical variable, and fitting linear regression models to nonlinear response patterns.

A comparison of laparoscopic Nissen fundoplication and Rossetti's modification in 239 patients

BACKGROUND

Laparoscopic Nissen fundoplication and the Rossetti modification represent two different surgical approaches to resolving gastroesophageal reflux disease (GERD). Concerns have arisen that the Rossetti modification results in increased postoperative dysphagia. In this study, we compared a group of patients who underwent a laparoscopic Nissen fundoplication with a group who had undergone the Rossetti modification to determine if there was a significant difference in postoperative dysphagia. Additionally, we wanted to confirm that the Nissen procedure performed laparoscopically could resolve GERD as successfully as the Rossetti modification, with no difference in operative complications.

METHODS

We prospectively collected data on 101 patients who underwent laparoscopic Nissen fundoplication and compared outcomes with those of 138 patients who had undergone the laparoscopic Rossetti modification in a previous series.

RESULTS

All patients experienced resolution of reflux symptoms. No statistically significant differences were found between the groups in terms of intraoperative or postoperative complications, conversions to open procedure, or length of hospitalization. Paradoxically, there was a significant difference in operating time between the Rossetti and the Nissen groups (70.6 min vs 45.6 min, p = 0.006). Postoperative dysphagia requiring dilation was significantly higher in the Rossetti group (21.7% vs 8.9%, p = 0.008). However, there was a significantly higher percentage of patients in the Rossetti group who had had esophagitis preoperatively (95.7% vs 86.1%, p = 0.009), although the proportion of patients having Barrett's esophagus was higher in the Nissen group (9.4% vs 24.8%, p = 0.001).

CONCLUSIONS

Both approaches resolved reflux symptoms without significant differences in complications, conversions, or length of stay. Preoperative differences between groups, as well as the method of sequentially comparing the two different procedures, prevent us from attributing greater postoperative dysphagia in the Rossetti group solely to the choice of surgical approach. Prospective randomized studies are needed to control for variables, such as surgical team experience and patient differences.

Accuracy of clinical judgment in neonatal jaundice

CONTEXT

Recommendations for management of jaundice in newborns presume thatjaundice is a reliable clinical finding and that the pattern and intensity of jaundice reflects the degree of elevation of the serum bilirubin level.

OBJECTIVES

To determine whether experienced observers agree in describing the extent of jaundice and to evaluate the reliability of visual assessment as an indication for the measurement of serum bilirubin levels.

DESIGN

Comparison of independent judgments of the extent of jaundice between examiners and with actual serum bilirubin measurements.

SETTING

Well-newborn nursery in an urban public hospital.

PARTICIPANTS

A convenience sample of 122 healthy term newborns whose bilirubin concentration was measured in the course of standard newborn care. Observers were experienced pediatric nurse practitioners, pediatric house staff, and pediatric attending physicians.

RESULTS

Agreement was moderately good for whether an infant's skin was darkly pigmented (K = 0.56). However, agreement between observers regarding the presence of jaundice at each specific body site was poor (0%-23% agreement beyond chance); correlation between estimated bilirubin concentrations was similarly poor (Pearson correlation coefficient, 0.37). Correlation between estimated and actual bilirubin values was slightly better (Pearson correlation coefficient, 0.43-0.54).

CONCLUSIONS

Clinical examination with visual assessment for jaundice in newborns is neither reliable nor accurate. The decision to perform serum bilirubin testing should be based on additional factors.

Association of mitral annular calcium with prior thromboembolic stroke in older White, African-American, and Hispanic men and women

Prior thromboembolic stroke was present in 57 of 188 white men (30%) with mitral annular calcium (MAC) and in 62 of 303 white men (20%) without MAC, in 42 of 65 African-American men (65%) with MAC and in 50 of 123 African-American men (41%) without MAC, and in 13 of 27 Hispanic men (48%) with MAC and in 21 of 58 Hispanic (36%) without MAC. Prior thromboembolic stroke was present in 164 of 614 white women (27%) with MAC and in 85 of 516 white women (16%) without MAC, in 111 of 193 African-American women (58%) with MAC and in 77 of 225 African-American women (34%) without MAC, and in 36 of 69 Hispanic women (52%) with MAC, and in 17 of 58 Hispanic women (29%) without MAC.

Risk factors for symptomatic peripheral arterial disease in older persons in an academic hospital-based geriatrics practice

OBJECTIVE

To investigate risk factors for symptomatic peripheral arterial disease (PAD) in older persons.

DESIGN

A retrospective analysis of charts from all older persons seen from January 1, 1998, through June 15, 1999, at an academic, hospital-based geriatrics practice.

SETTING

An academic, hospital-based geriatrics practice staffed by fellows in a geriatrics training program and full-time faculty geriatricians.

PATIENTS

A total of 467 men, mean age 80 +/- 8 years, and 1444 women, mean age 81 +/- 8 years, were included in the study.

MEASUREMENTS AND MAIN RESULTS

Symptomatic PAD was present in 93 of 467 men (20%) and in 191 of 1444 women (13%) (P = .001). Significant risk factors for symptomatic PAD by univariate analysis were: age (P = .021 in women); cigarette smoking, hypertension, diabetes mellitus, serum total cholesterol, serum high-density lipoprotein (HDL) cholesterol (inverse association), and serum low-density lipoprotein (LDL) cholesterol (P < .001 in men and women); obesity (P = .013 in men and .002 in women); and serum triglycerides (P = .027 in women). Significant independent risk factors for symptomatic PAD by stepwise logistic regression analysis were: age (odds ratio = 1.052 in men and 1.025 in women); cigarette smoking (odds ratio = 2.552 in men and 4.634 in women); hypertension (odds ratio = 2.196 in men and 2.777 in women); diabetes mellitus (odds ratio = 6.054 in men and 3.594 in women); serum HDL cholesterol (odds ratio = .948 in men and .965 in women); and serum LDL cholesterol (odds ratio = 1.019 in men and women).

CONCLUSIONS

Significant independent risk factors for symptomatic PAD in older men and women were age, cigarette smoking, hypertension, diabetes mellitus, serum HDL cholesterol (inverse association), and serum LDL cholesterol.

Bilateral emphysematous pyelonephritis with perirenal abscess cured by conservative therapy

Emphysematous pyelonephritis is a rare life-threatening infection of the renal parenchyma. It usually affects unilateral kidney and occurs mostly in diabetic patients. It is characterized by the presence of gas within the renal parenchyma and requires prompt diagnosis and early aggressive therapy. Bilateral emphysematous pyelonephritis is even more rare and is associated with high mortality. We describe a case of a 62-year-old diabetic woman who presented with nonketotic hyperosmolar coma and bilateral emphysematous pyelonephritis caused by Klebsiella pneumoniae. Diagnosis of bilateral emphysematous pyelonephritis was confirmed by an abdominal computed tomographic scan and microbiologic studies. Our patient was successfully treated using percutaneous catheter drainage and long-term antibiotic therapy.

Transtubular potassium concentration gradient (TTKG) and urine ammonium in differential diagnosis of hypokalemia

BACKGROUND

Hypokalemia is a common and sometimes serious clinical problem, whose etiological diagnosis can frequently be based on the patient's history and the clinical setting. Measurement of urinary indices such as excretory rate of K+, random urine K+ concentrations and blood acid-base parameters have been employed in the pathophysiological diagnosis, though with some pitfalls.

METHODS

To investigate the diagnostic usefulness of the transtubular potassium concentration gradient (TTKG) and urine ammonium in the differentiation of hypokalemia, we measured serum K+ and osmolality, random urine electrolytes, osmolality and ammonium, the urinary [Na]/[K] ratio (U(Na)/K), plasma aldosterone and TTKG in 7 patients with diarrhea, 6 with vomiting, 7 with mineralocorticoid excess, 6 with diuretic usage, and compared them with those of 7 overnight fasted and acid-loaded healthy volunteers.

RESULTS

The urine K+ concentrations did not reflect urinary loss of potassium according to the subjects' hydration status. U(Na)/k in the hypokalemic patients with mineralocorticoid excess (1.4 +/- 0.5) was lower than in normal subjects (2.3 +/- 0.4) (p<0.05). TTKG was higher in hypokalemic patients with mineralocorticoid excess (13.3 +/- 4.4) and diuretic usage (8.6 +/- 1.3) and lower in those with diarrhea (1.6 +/- 0.3) than in the normal controls (5.0 +/- 0.7) (p<0.5). TTKG in the patients with vomiting (3.5 +/- 0.6) was the same as in normal controls. TTKG was stronger correlated with the plasma aldosterone levels in the hypokalemic patients due to renal potassium loss. Urine ammonium concentrations of the acid-loaded normal subjects (73.3 +/- 5.0 mEq/L), patients with diarrhea (74.4 +/- 2.0 mEq/L) and patients with mineralocorticoid excess (68.7 +/- 6.9 mEq/L) were higher than in overnight-fasted normal subjects (31.3 +/- 4.9 mEq/L).

CONCLUSION

TTKG and random urine ammonium were useful in the pathophysiological differential diagnosis of hypokalemia.

Detection of Hantaan and Seoul viruses by reverse transcriptase-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP) in renal syndrome patients with hemorrhagic fever

BACKGROUND

Hemorrhagic fever with renal syndrome (HFRS), also called Korean hemorrhagic fever (KHF), is the most common cause of acute renal failure in the Far East. Two serotypes of hantavirus, Hantaan and Seoul viruses are known pathogens for HFRS in Korea.

PURPOSE

To elucidate the diagnostic applicability for the serotype diagnosis in HFRS patients, we used nested reverse transcriptase-PCR and restriction fragment length polymorphism (nRT-PCR/RFLP) to screen 2 prototype viruses, 11 virus isolates from HFRS patients, and 69 specimens obtained from 31 HFRS patients.

METHODS

The nRT-PCR was performed using primers specific for the G1 segments of the Hantaan (HF3 1140-1163, HB14 1363-1342) and Seoul (SF2 809-832, SB3 1200-1177) viruses. The initial PCR products were then further amplified using nested primers for the Hantaan (HF4 1141-1164, HB13 1360-1339) and Seoul (SF7 863-884, SB1 1165-1142 ) viruses. Amplified segments were then digested with restriction enzymes specific for either Hantaan (C1a I) or Seoul (Sac I) virus sequences.

RESULTS

In all cultured viruses, the serotypes identified by nRT-PCR/RFLP were consistent with those of PRNT. nRT-PCR/RFLP results indicated the presence of Hantaan virus in 10 patients and of Seoul virus in 15 patients. In 3 patients, both Hantaan- and Seoul-specific amplified bands were visualized in serially collected samples, and in 4 patients no amplicon was detected. Among 69 specimens, 55 were positive; these positive specimens were obtained between days 3 and days 33 of illness. The positive rate was not affected by the clinical phase, day of illness, or severity of HFRS.

CONCLUSIONS

nRT-PCR/RFLP is a rapid and convenient method for serotype diagnosis in most HFRS patients. It could also allow detection of genetic variation of hantavirus within the same serotype.

Novel mutations of the PKD1 gene in Korean patients with autosomal dominant polycystic kidney disease

The gene for the most common form of autosomal dominant polycystic kidney disease (ADPKD), PKD1, has recently been characterized and shown to encode an integral membrane protein, polycystin-1, which is involved in cell-cell and cell-matrix interactions. Until now, approximately 30 mutations of the 3' single copy region of the PKD1 gene have been reported in European and American populations. However, there is no report of mutations in Asian populations. Using the polymerase chain reaction and single-strand conformation polymorphism (SSCP) analysis, 91 Korean patients with ADPKD were screened for mutation in the 3' single copy region of the PKD1 gene. As a result, we have identified and characterized six mutations: three frameshift mutations (11548del8bp, 11674insG and 12722delT), a nonsense mutation (Q4010X), and two missense mutations (R3752W and D3814N). Five mutations except for Q4010X are reported here for the first time. Our findings also indicate that many different mutations are likely to be responsible for ADPKD in the Korean population. The detection of additional disease-causing PKD1 mutations will help in identifying the location of the important functional regions of polycystin-1 and help us to better understand the pathophysiology of ADPKD.