N-3 fatty acids inhibit vascular calcification via the p38-mitogen-activated protein kinase and peroxisome proliferator-activated receptor-gamma pathways

Fish oil supplementation is associated with lower risk of coronary artery disease in humans, and it has been shown to reduce ectopic calcification in an animal model. However, whether N-3 fatty acids, active ingredients of fish oil, have direct effects on calcification of vascular cells is not clear. In this report, we investigated the effects of eicosapentaenoic acid and docosahexaenoic acid (DHA) on osteoblastic differentiation and mineralization of calcifying vascular cells (CVCs), a subpopulation of bovine aortic medial cells that undergo osteoblastic differentiation and form calcified matrix in vitro. Results showed that N-3 fatty acids inhibited alkaline phosphatase (ALP) activity and mineralization of vascular cells, suggesting that they directly affect osteoblastic differentiation in vascular cells. By Western blot analysis, DHA activated p38-mitogen-activated protein kinase (MAPK) but not extracellular-regulated kinase (ERK) or Akt. An inhibitor of p38-MAPK partially reversed the inhibitory effects of DHA on osteoblastic differentiation and mineralization. Transient transfection experiments showed that DHA also activated peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Both p38-MAPK activator and PPAR-gamma agonists reproduced the inhibitory effects of DHA on CVC mineralization. Pretreatment with DHA also inhibited interleukin-6-induced ALP activity and mineralization. Together, these results suggest that N-3 fatty acids directly inhibit vascular calcification, and that the inhibitory effects are mediated by the p38-MAPK and PPAR-gamma pathways.

Identification and Characterization of a Sodium/Calcium Exchanger, NCX-1, in Osteoclasts and Its Role in Bone Resorption

We provide the first demonstration for a Na+/Ca2+ exchanger, NCX-1, in the osteoclast. We speculate that by using Na+ exchange, NCX-1 couples H+ extrusion with Ca2+ fluxes during bone resorption. Microspectrofluorimetry of fura-2-loaded osteoclasts revealed a rapid and sustained, but reversible, cytosolic Ca2+ elevation upon Na+ withdrawal. This elevation was abolished by the cytosolic introduction (by gentle permeabilization) of a highly specific Na+/Ca2+ exchange inhibitor peptide, XIP, but not its inactive analogue, sXIP. Confocal microscopy revealed intense plasma membrane immunofluorescence with an isoform-specific monoclonal anti-NCX-1 antibody applied to gently permeabilized osteoclasts. Electrophysiological studies using excised outside-in membrane patches showed a low-conductance, Na+-selective, dichlorobenzamil-sensitive, amiloride-insensitive channel that we tentatively assigned as being an NCX. Finally, to examine for physiological relevance, an osteoclast resorption (pit) assay was performed. There was a dramatic reduction of bone resorption following NCX-1 inhibition by dichlorobenzamil and XIP (but not with S-XIP). Together, the results suggest that a functional NCX, likely NCX-1, is involved in the regulation of osteoclast cytosolic Ca2+ and bone resorption.

Vagal regulation during bottle feeding in low-birthweight neonates: support for the gustatory-vagal hypothesis

The gustatory-vagal hypothesis proposes that gustatory stimulation elicits a coordinated vagal response manifested as an increase in ingestive behaviors (e.g., sucking) and a decrease in nucleus ambiguus vagal tone measured by decreases in the amplitude of respiratory sinus arrhythmia (RSA). The current study tested the gustatory-vagal hypothesis in a bottle feeding paradigm with 29 clinically stable, high-risk, low-birthweight neonates. The amplitude of respiratory sinus arrhythmia (RSA) was collected before, during, and after bottle feeding. Consistent with the gustatory-vagal hypothesis, RSA decreased during bottle feeding. In a longitudinal subsample of subjects, the pattern of RSA changes during the feeding paradigm was stable across two test sessions.

Impact of theophylline use in Wolff-Parkinson-White syndrome

Methylxanthine use in the treatment of apnea of prematurity is well documented. This drug is avoided in patients with aberrant pathways of conduction such as Wolff-Parkinson-White syndrome. In theory, methylxanthines enhance precipitation and exacerbation of tachyarrhythmias to which these patients are predisposed. This article reports a case of Wolff-Parkinson-White syndrome in a preterm neonate with severe apneic episodes in which methylxanthines were used. However, no adverse effects on cardiac rate or rhythm were encountered.

Apolipoprotein(a) kringle 4-containing fragments in human urine. Relationship to plasma levels of lipoprotein(a)

Apo(a) is a large glycoprotein of unknown function that circulates in plasma as part of lipoprotein(a). Apo(a) is structurally related to plasminogen and contains at least 10 kringle (K)4 repeats (type 1-10), a K5 repeat and sequences similar to the protease domain of plasminogen. Plasminogen generates two biologically active peptides: plasmin and angiostatin, a kringle-containing peptide. As a first step in determining if apo(a) generates a similar kringle-containing peptide, human urine was immunologically examined. Fragments ranging in size from 85 to 215 kD were immunodetected using antibodies directed against epitopes in the K4-type 2 repeat, but not the K4-type 9 repeat or protease domain, NH2-terminal sequence analysis revealed sequences specific for the K4-type 1 repeat, confirming that the fragments are from the NH2 terminus of the K4 array. The amount of urinary apo(a) rose in proportion to the plasma lipoprotein(a) concentration. Even individuals with trace to no apo(a) in plasma had immunodetectable apo(a) fragments in their urine. Intravenous administration of the human urinary apo(a) into mice resulted in the urine. These findings suggest that the apo(a) fragments found in urine are formed extrarenally and then excreted by the kidney.

Lumbar puncture in the evaluation of possible asymptomatic congenital syphilis in neonates

OBJECTIVE

To evaluate the usefulness of lumbar puncture (LP) in the initial evaluation of symptom-free infants for congenital syphilis.

STUDY DESIGN

We retrospectively studied infants who had successful LPs and were born to untreated or inadequately treated seropositive women between 1990 and 1993 in two hospitals in Washington, D.C. We identified 329 such symptom-free infants (syphilis group). The cerebrospinal fluid (CSF) VDRL was reactive in two (0.6%) infants. The CSF leukocyte and protein concentrations of these infants were compared with those in 84 symptom-free control infants who were born to seronegative women and who had LPs performed in 1993 to rule out sepsis because of associated risk factors. Control infants had negative results for bacterial cultures (CSF and blood) and bacterial antigen tests (CSF and urine).

RESULTS

Thirty control subjects and 67 infants in the syphilis group had traumatic taps (CSF erythrocytes > 500 x 10(6)/L), and hence were excluded from the analysis of cell count and proteins. Birth weights and gestational ages were similar in both groups. The CSF leukocyte and protein values were similar in the syphilis group and in control infants: mean CSF leukocytes 7.7 x 10(6)/L (mean 7.7/mm3, range 0 to 57/mm3, SD 8.8) versus 6.9 x 10(6)/L (mean 6.9/mm3, range 0 to 31/mm3, SD 7), p = 0.5, and mean protein concentration 981 mg/L (range 270 to 2280 mg/L, SD 376) versus 936 mg/L (range 360 to 1750 mg/L, SD 368), p = 0.96, respectively. The combination of CSF leukocyte values > 5 x 10(6)/L (> 5/mm3) or protein values > 400 mg/L (> 40 mg/dl) was found in 97.8% of the infants in the syphilis group, compared with 95.3% of the control group.

CONCLUSION

Because of the low yield of reactive CSF VDRL and the similar CSF leukocyte and protein values in the syphilis group and the control infants, the role of routine LP in the initial evaluation of symptom-free infants for congenital syphilis should be reconsidered.

Postneonatal screening for congenital syphilis

The incidence of congenital syphilis has recently reached epidemic proportions. With the resurgence of this important clinical entity, currently recommended screening procedures may be inadequate. We describe three cases that highlight the limitations of these screening procedures. All these infants had associated maternal risk factors for congenital syphilis, such as poor prenatal care and illicit drug use. All the infants and mothers were seronegative for syphilis at the time of birth but the infants became seropositive at 2 months of age. These cases support the need to reexamine current screening policies. In addition to prenatal and at-delivery screenings for congenital syphilis, it may be appropriate to screen infants born to high-risk mothers at 4 to 8 weeks of age.

Morbidity and mortality of infants born before arrival at the hospital

Recently, a number of infants have been born at home, in an ambulance, car, etc., before arrival at the District of Columbia General Hospital. Many of these infants had poor outcome. To evaluate the prevalence and outcome of these infants, we reviewed medical records of all infants born before arrival at the hospital (out-born infants) and compared them with in-hospital deliveries from July 1988 to June 1992. Data were analyzed using Fisher's Exact Test and chi-square test. There were 151 (1.8%) out-born infants and 8,169 (98.2%) in-born infants during this 4-year period. Infants in both groups were predominantly black (85%). The following were significant differences (P < 0.001) between out-born and in-hospital deliveries, respectively: illicit drug exposure 35% vs 21%; low-birth-weight (< 2,500 g) infants 39% vs 16%; intensive care unit admissions 29% vs 15%; and neonatal deaths per 1,000 live births 80 vs 7. We conclude that there is a twofold increase in the morbidity (required intensive care) and an 11-fold increase in the mortality among out-born infants compared with infants delivered in-hospital. Even though out-born infants were < 2% of the total deliveries, they accounted for 17% of total neonatal mortality.

Effect of intrauterine cocaine exposure on respiratory distress syndrome in very low birthweight infants

To evaluate the effect of intrauterine cocaine exposure on lung maturity of very low birthweight infants, the medical records of all infants with birthweight < 1500 g born between January 1989 and December 1990 at DC General Hospital were reviewed. Infants with conditions known to cause lung maturity, severe congenital anomalies, proven early sepsis, and birthweight > or = 500 g were excluded. A total of 69 infants were included in the study. Chest roentgenograms of these infants were evaluated by a pediatric radiologist, who was unaware of the infant's medical course, for evidence of respiratory distress syndrome (RDS), and radiological findings were correlated with clinical signs. Forty infants were exposed to cocaine in utero (cocaine group) and 29 were not exposed (noncocaine group). African-American ethnicity, pregnancy-induced hypertension, prolonged rupture of membranes, and alcohol use were similar in both groups. Tobacco use among cocaine group mothers was higher (42.5% versus 13.8%; P = .01). Gestational age (28.3 +/- 2.8 versus 28.3 +/- 3 weeks), birthweight (966 +/- 282 versus 1059 +/- 295 g), male gender, and Apgar scores were similar in both groups. Thirty (75%) infants in the cocaine group developed RDS compared with 19 (66%) in the noncocaine group (P > .05). Using multiple logistic regression analysis and controlling for smoking, alcohol use, and prolonged rupture of membranes (24 to 72 hours), the incidence of RDS between the groups remained statistically insignificant. We conclude that intrauterine cocaine exposure does not alter the incidence of RDS in very low birthweight infants.

Occurrence of craniosynostosis in neonates exposed to cocaine and tobacco in utero

The occurrence of craniosynostosis (premature closure of cranial sutures) has been reported to be 3 to 5 per 10,000 live births. The incidence is even lower among African-American infants. The District of Columbia General Hospital serves primarily the African-American population with approximately 2000 deliveries a year. In the last 10 years, three neonates with craniosynostosis have been born at DC General Hospital; all three infants were African Americans. These infants were exposed to cocaine and tobacco in utero, which suggests a possible association between intrauterine cocaine and tobacco exposure and premature closure of cranial sutures. Possible pathogenesis of craniosynostosis in association with cocaine and tobacco use is discussed.

An interesting case presentation: a possible new route for perinatal acquisition of Chlamydia

Chlamydia trachomatis is currently the most common sexually transmitted disease in the United States. The prevalence in pregnant women ranges between 2% and 47%. It is well known that C trachomatis can be transmitted from the genital tract of an infected mother to her newborn infant, causing conjunctivitis or pneumonia or both, along with their longstanding complications. A review of the literature failed to show, however, conclusive evidence of transmission of infection to the newborn infant when the infant was born by cesarean section with intact amniotic membranes. We present a case of a young black woman with a history of chlamydia cervicitis during pregnancy whose infant was delivered by cesarean section because of failure to progress. She gave birth to a healthy term infant who developed ophthalmia neonatorum on the 3rd day of life. Examinations of conjunctival scrapings with direct fluorescent staining (chlamydia MicroTrak) performed on the 1st and 3rd day of life were positive. The initial test was performed because of the maternal history. The infant was mildly symptomatic at the time the study was repeated for confirmation. Our findings strongly suggest the possibility of either transmembrane or transplacental route of infection in the pathogenesis of neonatal chlamydia infection. Further study is needed to confirm this possibility.

Gastrointestinal complications after cardiac transplantation: a spectrum of diseases

Cardiac transplantation has become an accepted treatment modality for end-stage cardiac failure. The gastrointestinal (GI) tract represents a potential source of posttransplant morbidity and mortality. To define the scope of this problem, records of all patients undergoing cardiac transplantation at UCLA between January 1984 and July 1989 were reviewed. In all, there were 120 patients (90 males and 30 females) with a mean age of 45.4 yr. Among them, there were 61 patients (51%) who developed a total of 112 posttransplant GI complications. Of the entire 120 patients, 41 (34%) developed minor complications and 20 (17%) sustained major GI morbidity. Eighteen patients (15%) underwent either endoscopy or surgical intervention. These data suggest that most cardiac transplant recipients will experience some form of GI complication, although most are minor and can be managed conservatively. However, when major, life-threatening complications occur, evaluation and intervention should proceed expeditiously. The gastroenterologist and GI surgeon should play complimentary roles in the care of these complicated patients.

Immunosuppressive activity of cord blood leukocytes

The in vitro effects of cord blood cells from term and preterm infants on cell-mediated immune responses by adult lymphocytes were studied. The experiments showed that cord blood cells were potent suppressors of antigen- and mitogen-induced proliferation of adult T cells. In contrast to the previously reported observations with adult suppressor cells, the cord blood cells did not require mitogenic activation to exert their suppressive activity. It was also found that a similar, if not identical, suppressive activity was released into the fluid phase when cord blood cells were placed in tissue culture for three to five days. Studies with subpopulations of cord blood cells showed that the suppressive factor was released from rosette-forming T lymphocytes, but not from cell populations that were depleted of T cells. In addition, the production of and the action of the soluble suppressive factor was inhibited by indomethacin.