MRSA infections in children.

MRSA infections continue to be a serious and formidable challenge to health care providers and their prevalence is increasing exponentially. In the past, MRSA infections were observed only in hospitalized patients whereas now they are encountered in the outpatient setting. Understanding the pattern of the widespread distribution of MRSA as well as the factors associated with its spread are paramount to its recognition and eradication. The current state of MRSA transmission, control and management is reviewed.

Chronic theophylline exposure increases agonist and antagonist binding to A1 adenosine receptors in rat brain.

Chronic treatment of rats with theophylline (75mg/kg twice-daily for 21 consecutive days) significantly increased the specific binding of [3H]CHA and [3H]DPCPX in cerebral cortical membranes. The absolute increase in the number of binding sites following theophylline treatment was approximately the same for each ligand, although this number represents a larger percentage of the total sites available to [3H]CHA. Saturation analysis of [3H]DPCPX binding indicated that theophylline treatment increased the maximum number of binding sites from 799 +/- 13 to 920 +/- 22 fmol/mg protein, while the affinity of [3H]DPCPX for A1 receptors was unaltered. These results suggest that chronic theophylline exposure produces both an increase in the number of A1 adenosine receptors and an enhancement of coupling of these receptors to G proteins.

Theophylline-induced upregulation of A1-adenosine receptors associated with reduced sensitivity to convulsants.

Chronic administration of theophylline (50 mg/kg twice daily for 14 consecutive days) significantly increased the specific binding of [3H]CHA in membranes of the cerebral cortex and cerebellum of the rat, but not in membranes derived from the hippocampus or diencephalon. To characterize further the upregulation of A1 = adenosine receptors induced by theophylline, saturation analysis with [3H]CHA was performed in membranes of the cerebral cortex and cerebellum. In both saline- and theophylline-treated cortical membranes the binding isotherms for [3H]CHA could be resolved into receptor affinity states having respectively high (KH) and low (KL) affinity for [3H]CHA. The high and low affinity dissociation constants obtained from theophylline-exposed membranes of the cerebral cortex were 1.14 nM and 25.2 nM and did not differ significantly from the corresponding values in saline-treated animals. Chronic exposure to theophylline did, however, produce significant increases in the densities of both the high and low affinity forms of A1-adenosine receptors in the cerebral cortex. Qualitatively and quantitatively similar results were observed in cerebellar membranes. These results suggest that chronic exposure to theophylline increases the density of A1-receptor in the cerebral cortex and cerebellum with no concomitant changes in the ability of [3H]CHA to distinguish separate agonist affinity states of the receptor. The physiological significance of theophylline-induced upregulation was assessed by determining seizure thresholds for convulsants in rats treated chronically with saline or theophylline.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiodensity of the proposed new penny.

In 1973 the United States Mint proposed replacing the bronze penny with a less expensive penny made of aluminum. Pediatricians and pediatric radiologists, by testifying that aluminum coins are difficult to see on radiographs, helped defeat that legislation. Now the Mint again proposes a less expensive penny, one made principally of zinc. This proposed penny is radiopaque and will be easily identified on radiographs.

OEIS complex (omphalocele-exstrophy-imperforate anus-spinal defects) in monozygotic twins.

The omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex is a consistent and recognizable pattern of midline abdominal and pelvic defects. It is rare, affecting 1 in 200,000 to 400,000 pregnancies and is even rarer in twin gestations. This is an autopsy study of OEIS complex in monozygotic twins after pregnancy termination at 20 weeks of gestation. Unremarkable family history but concordance of monozygotic twins for the defects may support the theory that early malformation complexes, e.g., OEIS, and monozygotic twinning are manifestations of the same disturbance of early blastogenesis.

Bacterial and viral etiology of severe infection in children less than three months old in the highlands of Papua New Guinea.

OBJECTIVE: Determine the bacterial and viral etiology of severe infection in young Papua New Guinean infants as part of a multicenter study in four developing countries aimed at improving case management guidelines. METHODS: Between March, 1991, and April, 1993, children aged <3 months were recruited at the outpatient department of Goroka Base Hospital, Papua New Guinea (PNG). Children with pre-defined inclusion criteria were enrolled, a history was taken and clinical examination was performed. Blood and urine were collected from children with signs suggestive of severe disease together with eye, umbilical and pernasal swabs as appropriate. Nasopharyngeal aspirates (NPAs) were collected from children with and without signs of severe disease for identification of viruses and Chlamydia trachomatis by direct fluorescent antibody staining. RESULTS: 3280 infants were triaged and 2168 enrolled, among whom 968 had signs suggestive of severe disease. Group A Streptococcus (Streptococcus pyogenes) and Staphylococcus aureus were the most important bacterial pathogens isolated from children < 1 month old with severe infections, and Streptococcus pneumoniae, S. pyogenes and Staphylococcus aureus were most important in older children. Of 292 eye swabs 19 (7%) grew Neisseria gonorrhoeae. Of 116 umbilical swabs 51 (44%) grew S. pyogenes and 45 (39%) grew Staphylococcus aureus. Respiratory syncytial virus was the most important viral cause of acute lower respiratory infection. CONCLUSIONS: S. pyogenes, S. pneumoniae and Staphylococcus aureus are important causes of severe infection in young children in the PNG highlands. It is necessary to improve access to clean water, promote hand-washing in the hospital and at home and investigate further the use of maternal immunization for the prevention of severe disease in young infants.

High rates of Chlamydia trachomatis infections in young Papua New Guinean infants.

OBJECTIVE: Determine the importance of Chlamydia trachomatis in the etiology of severe infection in young Papua New Guinean infants. METHODS: Between March, 1991, and April, 1993, children <3 months old were recruited as outpatients at Goroka Base Hospital, Papua New Guinea, as part of a multicenter study in four developing countries. Children with predefined inclusion criteria were enrolled. C. trachomatis was identified by direct fluorescent antibody staining in nasopharyngeal aspirates (NPAs) collected from children with and without signs of severe disease and eye swabs from children with and without conjunctivitis. Two to three radiologists read chest radiographs without knowledge of clinical and laboratory findings. RESULTS: Of 3280 outpatients seen 2168 enrolled, 955 NPAs were tested for C. trachomatis and 549 chest radiographs were read. Of 210 eye swabs from children with conjunctivitis 57% were positive for C. trachomatis compared with 8% from 167 children with no conjunctivitis. The prevalence of C. trachomatis in NPAs was 9% in asymptomatic children and 18 and 33% in children with nonsevere or severe pneumonia, respectively. C. trachomatis in NPAs was strongly associated with clinically severe pneumonia [odds ratio (OR), 2.91], reduced arterial oxygen saturation (OR 2.58) and radiographic evidence of pneumonia (OR 5.84) and was also associated with pneumococcal bacteremia (OR 3.48). CONCLUSIONS: In Papua New Guinea Chlamydia must be considered as a cause when treating pneumonia in infants, and effective treatment and prevention of sexually transmitted diseases are urgently needed for a number of reasons, including the need to curb high rates of chlamydial infection in women and infants.

Legal problems related to obstetrical ultrasound.

Malpractice suits related to fetal anomalies are now the most common type of litigation involving ultrasound, surpassing ectopic pregnancy. Missing an anomaly on a sonogram performed for a standard indication, such as dating, is the most frequent type of litigation. Other causes of litigation include invented anomalies and unrecognized anomalies that are visible in retrospect on the ultrasonic images. Rarer causes of malpractice problems relate to failure to communicate the results of a sonogram in a timely fashion, failure to inform the patient of the findings about the sonogram at the time the patient is seen, and failure to perform ultrasound studies for anomalies when there is clinical indication to do so, such as elevated alpha-fetoprotein or polyhydramnios. The level of protection given by the obstetrical guidelines are discussed. Particular areas of concern relate to litigation involving missed fetal heart malformations, spina bifida, absent distal limbs, and twins.

B-scan ultrasound in the diagnosis of popliteal aneurysms.

Sonography gives a characteristic picture of popliteal aneurysms, with an easily demonstrable connection of the sonolucent aneurysmal sac with the popliteal artery. It is a good screening procedure for suspected aneurysms and for patients with popliteal pain, mass, or sudden distal ischemia. Three case reports of five popliteal aneurysms diagnosed by ultrasound are presented. A case of neurofibrosarcoma occurring in the popliteal fossa is shown for comparison.

Doppler ultrasound and maternal erythrocyte fragility.

Maternal erythrocyte fragility was studied in eight controls and in 16 women exposed to Doppler ultrasound monitoring during labor. Blood samples were taken before and after Doppler monitoring and no significant change in erythrocyte fragility was seen, although there was a trend toward increased fragility in patients exposed continuously for more than seven hours.

Fetal genitourinary tract anomalies: evaluation, operative correction, and follow-up.

The prenatal diagnosis of a genitourinary anomaly was made in 53 fetuses. Sonographic findings, antenatal course, and postnatal treatment and outcomes were examined. No interventional therapy was undertaken in utero, and the natural history could be examined in the 44 of 53 (83%) who did not electively terminate their pregnancies. Twenty-three of the total 53 (43%) had unilateral disease and 30 (57%) had bilateral involvement. Thirty-five of 53 (66%) survived, with 22 undergoing operative therapy postnatally. In all but one of the 35 survivors, the anomaly was isolated to the genitourinary tract, and the majority of surviving fetuses had unilateral disease. Oligohydramnios was present in only three of 35 survivors, and none had severe oligohydramnios. Nine of 53 women underwent termination of pregnancy and nine others experienced a neonatal death. All 18 of their fetuses had bilateral disease, with oligohydramnios present in 14 (78%). All five fetuses with chromosomal abnormalities were found in this group of 18. The majority of fetuses with a genitourinary anomaly will do well postnatally. Pulmonary hypoplasia, extrarenal anomalies, and chromosomal defects are frequent findings in the minority with poor outcomes. A multidisciplinary approach to management of the pregnancy with a fetal genitourinary tract anomaly is essential to optimize outcome.

Criteria for the prenatal diagnosis of classic bladder exstrophy.

OBJECTIVE: To define ultrasonographic criteria for the prenatal diagnosis of classic bladder exstrophy. METHODS: Forty-three prenatal ultrasound scans were studied from 25 pregnancies in which live delivery of an infant with classic bladder exstrophy occurred. The diagnosis of bladder exstrophy could be made retrospectively in 29 prenatal studies from 17 pregnancies. The time of the fetal ultrasound varied from 14-36 weeks' gestation (mean 23). The diagnosis of bladder exstrophy was made before delivery in only three cases. RESULTS: Five factors associated with bladder exstrophy were identified: 1) The bladder was not visualized on ultrasound in 12 of 17 cases (71%); 2) a lower abdominal bulge representing the exstrophied bladder was seen in eight of 17 cases (47%); 3) a small penis with anteriorly displaced scrotum was identified in eight of 14 males (57%); 4) the umbilical insertion was low set in five of 17 cases (29%); and 5) abnormal widening of the iliac crests was seen in three of 17 cases (18%). CONCLUSION: The prenatal diagnosis of bladder exstrophy should be considered any time the bladder is not visualized or any of the aforementioned factors are noted.

Routine detection of human rotavirus by latex agglutination: comparison with enzyme-linked immunosorbent assay, electron microscopy and polyacrylamide gel electrophoresis.

A commercially available latex agglutination test, RotaScreen (Mercia Diagnostics Ltd., West Byfleet, Surrey, U.K.) was evaluated for the detection of human rotaviruses in stool specimens. The results obtained were compared with those from 3 other routine assay systems used in this laboratory: enzyme-linked immunosorbent assay (ELISA), electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) of viral ribonucleic acid. 400 stool samples were examined by the 4 assay systems under routine conditions. RotaScreen latex agglutination was found to be more sensitive than EM and PAGE, and highly specific for rotavirus antigens.

Temporal relationship between A1 adenosine receptor upregulation and alterations in bicuculline seizure susceptibility in rats.

The temporal requirements for theophylline-induced upregulation of A1 adenosine receptors and elevation of seizure threshold were examined. Chronic theophylline exposure (75 mg/kg twice daily) elicited a significant upregulation of [3H]cyclohexyladenosine ([3H]CHA) binding sites following 7 and 14 days of treatment. Alterations in seizure threshold followed a similar temporal pattern of development. The reversibility of theophylline-induced upregulation of high affinity [3H]CHA binding sites was complete at 10 days following cessation of theophylline administration, while the alteration of seizure threshold required 21 days to return to control values.

Dandy-Walker syndrome: recognition by sonography.

The sonographic appearance of the Dandy-Walker malformation is not well known. Experience with sonography in the recognition of the Dandy-Walker syndrome in four neonates is presented. Three cases were discovered serendipitously: one during obstetric evaluation for uncertain gestational age and two in asymptomatic neonates. The typical sonographic features are a triangular posterior fossa cyst, a dilated aqueduct of Sylvius in communication with the cyst, elevation and hypoplasia of the cerebellum, and variable dilatation of the third and lateral ventricles. Sonography is often the first diagnostic procedure performed on these patients and can be very useful in recognizing the anomaly.

Ventriculitis in the neonate: recognition by sonography.

In the neonate, ventriculitis and inflammatory infiltration of the choroid plexus usually accompany meningitis. Intracranial sonograms were reviewed from six infants referred for evaluation because of clinically suspected or confirmed ventriculitis. Findings included ventricular dilatation with irregularity of the ventricular margins and increased periventricular echogenicity. The choroid plexus margins also appeared poorly defined with loss of the normally smooth contour. Echogenic material was seen within the lateral ventricles, and intraventricular septa formation resulted in ventricular compartmentalization. Parenchymal changes included periventricular cavitation and a diffuse increase in cortical echogenicity. The ventricular pathology was more apparent on sonograms than on computed tomographic scans obtained at comparable times. In particular, sonography better demonstrated the ventricular compartmentalization from intraventricular septum formation. Identification of such partial ventricular isolation is especially important when treatment involves intraventricular shunt placement or the administration of intraventricular antibiotics. This experience suggests sonography should be the initial imaging method for evaluating ventriculitis and its complications in the newborn.

Prenatal ultrasonic detection of anomalies with a lethal or disastrous outcome.

Although rare, a number of fetal anomalies can be detected with ultrasound in which the prognosis is either fetal death or minimal development. Anomalies of this type include anencephaly, holoprosencephaly, hydranencephaly, iniencephaly, cystic hygroma with hydrops, cystadenomatoid malformation of the lung with hydrops, conjoined twins of some types, renal agenesis, bilateral renal dysplasia, lethal dwarfing syndromes, and some forms of hydrops. Syndromes in which the severe form only are fatal include intracranial teratoma, encephalocele, pentalogy of Cantrell, vein of Galen aneurysm, the limb body wall complex, and infantile polycystic kidney. Sonographic findings of these conditions and other rarer lethal lesions are reviewed.

Work of breathing associated with pressure support ventilation in two different ventilators.

The purpose of this study was to compare the work of breathing during pressure support ventilation (PSV) with positive end expiratory pressure (PEEP) utilizing the Siemens SV300 (SV300) and Dräger Evita 4 (EV4) ventilators. Our hypothesis was that patients' work of breathing (WOB(P)) would be unchanged in PSV utilizing flow triggering (FT) in both the SV300 and EV4. We compared two ventilators using six healthy, intubated, sedated, spontaneously breathing pigs weighing approximately 10 kg each. WOB(P) (j/L) and ventilator work of breathing (WOB(V)) (j/L) were measured using a portable monitor which utilizes an esophageal balloon and flow transducer. Each breath was further analyzed for duration of inspiratory effort and negative deflection of pressure needed to trigger PSV. Animals were studied with the SV300 and EV4 on a pressure support of 5 cmH(2)O and PEEP settings of 0 and 5 cmH(2)O. Data were analyzed using the Wilcoxon signed rank test with significance set at P

Comparison of work of breathing between two neonatal ventilators utilizing a neonatal pig model.

OBJECTIVE: The purpose of this study was to determine whether variations in the delivery systems of continuous positive airway pressure between two ventilators would lead to differences in patient work of breathing (WOBp). DESIGN: Comparison of two neonatal ventilators with a neonatal pig model. SETTING: Animal laboratory. SUBJECTS: Thirty healthy, intubated, sedated, spontaneously breathing neonatal piglets weighing 1.0-2.0 kg. INTERVENTIONS: Patient work of breathing (WOBp) (gm cm/kg) was measured by using measurements based on an esophageal balloon and a flow transducer. Each breath was analyzed for ventilator response times (in msecs) and negative deflection of pressure. Each animal was studied with the Siemens SV300 and Drager Babylog 8000, on continuous positive airway pressure settings of 0, 3, and 5 cm H2O. Data were analyzed by using Wilcoxon's Signed Rank Test with significance of p 1 cm H2O negative pressure before flow was available with the Babylog. CONCLUSIONS: In intubated patients, maximum energy expenditure occurs at the initiation of ventilator breaths. WOBp in neonatal pigs was significantly increased. The response time of the ventilators may explain the differences in initiation of flow times and patient work. These differences may have important implications for energy kinetics, weight gain, and duration of mechanical ventilation in preterm neonates.

Ultrasonic clues to the detection of chromosomal anomalies.

The ultrasonic detection of fetal anomalies may well be the most challenging aspect of diagnostic ultrasound and, because ultrasonic clues to a chromosomal anomaly may be subtle, much depends on high quality ultrasound. Although difficult, the field is exciting and rewarding. It is hoped that recognition of the various common manifestations of chromosomal anomalies described in this article will increase the number of chromosomal anomalies detected and ameliorate the consequences of these disorders.