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Biomedical subjects

W D Winters

Publications and source records attributed to W D Winters.

At least 37 records · Page 2Linked to original sources
PubMed1995

A prospective study of femoral catheter-related thrombosis in children.

OBJECTIVES: To establish the incidence and correlate clinical findings of femoral venous catheter-related thrombus formation in critically ill children. RESEARCH DESIGN: Observational prospective blinded study. SETTING: University-affiliated pediatric hospital intensive care unit. PATIENTS: Twenty children admitted to the pediatric intensive care unit who had percutaneous femoral venous catheters placed while in the pediatric intensive care unit. INTERVENTIONS: None. MEASUREMENTS: Duplex Doppler ultrasonography evaluation of femoral vein catheters at 1 to 2, 3 to 5, and 7 to 10 days after placement was used to detect the presence of thrombus formation and venous occlusion. Demographic patient data, pediatric risk of mortality scores, and clinical findings, including leg swelling and whether catheters would aspirate blood, were also recorded. Continuous data were analyzed using the Mann-Whitney U Test, and categorical data were compared with Fisher's Exact Test. Statistical significance was assigned at a P value of .05 or less. CONCLUSIONS: The overall incidence of catheter-related femoral vein thrombus formation was 35% (7/20). Ipsilateral leg swelling and the inability to aspirate blood from the catheter were significantly associated with thrombus formation. Patients who developed thrombi were younger and smaller than those who did not. In six of seven patients, thrombus formation was clinically occult when first demonstrated by ultrasonography.

Catheterization, Central Venous↗
PubMed1995

Nontraumatic pediatric musculoskeletal MR imaging: comparison of conventional and fast-spin-echo short inversion time inversion-recovery technique.

PURPOSE: To compare conventional short inversion time inversion-recovery (STIR) with fast spin-echo (FSE) STIR techniques to evaluate suspected nontraumatic musculoskeletal abnormalities. MATERIALS AND METHODS: Thirty STIR and FSE-STIR examinations in 26 pediatric patients with suspected nontraumatic musculoskeletal abnormalities were prospectively evaluated. Qualitative (subjective) and quantitative (five-point rank score) analyses of the images were performed. RESULTS: FSE-STIR was faster than STIR (mean, 2 minutes 25 seconds and 6 minutes 35 seconds, respectively). Fat suppression was slightly better with STIR. Image degradation due to motion was judged similar. Lesion contrast to muscle was slightly better with STIR than FSE-STIR, and lesion contrast to fat was equivalent. Qualitatively, lesion conspicuity was similar: All lesions were seen with both techniques. CONCLUSION: FSE-STIR can replace STIR when an inversion-recovery fat-suppression sequence is desired. Considerable imaging time is saved.

Adolescent↗
PubMed1995

Hypercalciuria and nephrocalcinosis in the oculocerebrorenal syndrome.

The oculocerebrorenal (Lowe) syndrome is an X-linked recessive disorder characterized by congenital cataracts, hypotonia, developmental delay, poor growth and renal tubular dysfunction. Although the disorder has been mapped to chromosome Xq24-26, the underlying metabolic defect remains unknown. The renal component of the Lowe syndrome comprises tubular dysfunction, that is tubular proteinuria and generalized aminoaciduria progressing to the renal Fanconi syndrome, with later glomerular disease. Clinical problems typically include polyuria, acidosis, hypophosphatemia with rickets and eventually end stage renal disease. Hypercalciuria and its sequelae (nephrocalcinosis and nephrolithiasis) have not been described as cardinal features of the untreated disorder although they reportedly complicate vitamin D and calcium therapy of rickets. We discuss 5 boys with congenital cataracts, hypotonia, developmental delay, failure to thrive and the renal Fanconi syndrome who were diagnosed with the Lowe syndrome and in whom hypercalciuria was documented at diagnosis. We conclude that hypercalciuria and its sequelae may occur commonly in patients with the Lowe syndrome as a component of tubular dysfunction or a complication of therapy.

Calcium↗
PubMed1993

In vivo studies of the effect of magnetic field exposure on ontogeny of choline acetyltransferase in the rat brain.

Developmental increases of the activity of choline acetyltransferase (ChAT) were examined in the brains of fetuses and offspring from parent rats continuously exposed to a 500 mG, 60 Hz circularly polarized (CP) magnetic field (MF) prior to pregnancy, and further, during pregnancy and lactation. In developing rats between 12 days and 20 days of embryogenesis that were housed in a control unit, i.e., nonexposed to MF, the specific activity of ChAT in whole brain specimens increased from 2.4% to 6.9% of adult activity, while specific activity of ChAT in rat brain specimens between 12 days of embryogenesis and 10 days of postpartum increased from 2.4% to 21.6% of adult activity. On the other hand, the specific activity of ChAT in whole brain specimens from rats under housed MF exposure conditions was found to increase from 2.6% to 6.7% of adult activity between 12 days and 20 days of embryogenesis and from 2.6% to 21.6% of adult activity between 12 days of embryogenesis and 10 days postpartum. Furthermore, the effect of the same test magnetic environment on the specific activity of ChAT in the brains of parental rats was examined in order to determine whether magnetic field exposure of parental rats might reflect onto the development of fetal brain. It was observed that continuous exposure of parental rats to a 500 mG, 60 Hz CP MF did not show any significant changes in the specific activity of ChAT in the septodiagonal band complex, dorsal and ventral hippocampus, striatum, and frontoparietal cerebral cortex, as compared with the same brain regions of control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Environmental magnetic fields: influences on early embryogenesis.

A 10-mG, 50 to 60-Hz magnetic field is in the intensity and frequency range that people worldwide are often exposed to in homes and in the workplace. Studies about the effects of 50- to 100-Hz electromagnetic fields on various species of animal embryos (fish, chick, fly, sea urchin, rat, and mouse) indicate that early stages of embryonic development are responsive to fluctuating magnetic fields. Chick, sea urchin, and mouse embryos are responsive to magnetic field intensities of 10-100 mG. Results from studies on sea urchin embryos indicate that exposure to conditions of rotating 60-Hz magnetic fields, e.g., similar to those in our environment, interferes with cell proliferation at the morula stage in a manner dependent on field intensity. The cleavage stages, prior to the 64-cell stage, were not delayed by this rotating 60-Hz magnetic field suggesting that the ionic surges, DNA replication, and translational events essential for early cleavage stages were not significantly altered. Studies of histone synthesis in early sea urchin embryos indicated that the rotating 60-Hz magnetic field decreased zygotic expression of "early" histone genes at the morula stage and suggests that this decrease in early histone production was limiting to cell proliferation. Whether these comparative observations from animal development studies will be paralleled by results from studies of human embryogenesis, as suggested by some epidemiology studies, has yet to be established.

Animals↗
PubMed1992

Sonographic diagnosis of intestinal malrotation in infants: importance of the relative positions of the superior mesenteric vein and artery.

OBJECTIVE: An abnormal relative position of the superior mesenteric vein and artery can be present in patients with intestinal malrotation. We undertook this retrospective study to see how often we could determine the relative position of these vessels on abdominal sonograms in infants and how often abnormal position of the vessels was associated with malrotation. MATERIALS AND METHODS: We reviewed the radiology files and medical records of 337 infants with vomiting who were referred for sonography because of possible pyloric stenosis. We used sonograms and written reports to determine the position of the superior mesenteric vessels. The position was considered normal when the superior mesenteric vein was to the right of the superior mesenteric artery on transverse sonograms. The position was considered abnormal when the vein was directly ventral to the artery or when the vein was to the left of the artery. Sonographic findings were compared with results of upper gastrointestinal series when possible and with clinical outcome. RESULTS: The relative positions of the superior mesenteric vein and artery were evident in 249 (74%) of the 337 patients. Abnormal orientation of the mesenteric vessels was detected in nine patients. In five patients, the superior mesenteric vein was located to the left of the artery, and all five had intestinal malrotation. In four patients, the superior mesenteric vein was directly ventral to the artery, and one of these had malrotation. CONCLUSION: Sonographic assessment of the relative positions of the mesenteric artery and vein is an important adjunct in the examination of infants with suspected pyloric stenosis. Patients in whom sonograms show an abnormal position of the vessels should have further examination to detect malrotation.

Congenital Abnormalities↗
PubMed1991

The effects of benzodiazepines on basal and isoproterenol-stimulated N-acetyltransferase activity by the rat pineal gland, in vivo and in vitro.

The present study examined the effects of "peripheral," "central," and "mixed" benzodiazepine agonists and antagonists on the nocturnal rise in rat pineal NAT activity in vivo and the isoproterenol-stimulated NAT activity of pineals in organ culture. Administration of the central agonist clonazepam or the mixed agonist-antagonist diazepam, 4 hr after dark, at a dose of 25 mg/kg each, inhibited nocturnally elevated NAT 20 min later, while this same dose of the peripheral agonist RO 54864 elevated NAT activity. In a second study these agents were administered in vivo 1 hr before dark, at a dose of 3, 10, or 25 mg/kg i.p. and tested 4 hr after dark for in vitro rat pineal NAT activity. None of these agents affected NAT activity at the 3- or 10-mg/kg dose, but RO 54864 25 mg/kg did induce elevated activity. In a third study, all of these agents prolonged the time period for NAT induction by isoproterenol in rat pineals cultured for 48 hr before stimulation. The data suggests that benzodiazepine stimulation of NAT activity in vitro is not specific to "central" or "peripheral" benzodiazepine receptors and that inhibition of melatonin production in vivo occurs either at some step before NAT induction or is involved with the inhibition of pineal HIOMT activity.

Analysis of Variance↗
PubMed1990

Influence of 60-Hz magnetic fields on sea urchin development.

Continuous exposure of sea urchin (Strongylocentrotus purpuratus) embryos at 18 degrees C to a cyclic 60-Hz magnetic field at 0.1 mT rms beginning 4 min after insemination caused a significant developmental delay during the subsequent 23 hours. No delay in development was recorded for periods up to 18 hours after fertilization. At 18 h, most embryos were in the mesenchyme blastula stage. At 23 h, most control embryos were in mid-gastrula whereas most magnetic-field-exposed embryos were in the early gastrula stage. Thus an estimated 1-h delay occurred between these developmental stages. The results are discussed in terms of possible magnetic-field modification of transcription as well as interference with cell migration during gastrulation. The present study extends and supports the growing body of information about potential effects of exposures to extremely-low-frequency (ELF) magnetic fields on developing organisms.

Animals↗
PubMed1990

Urinoma drainage for neonatal respiratory insufficiency.

This report describes two newborn males with posterior urethral valves, perirenal urinomas and respiratory distress. A 400 cc urinoma was drained percutaneously with resolution of respiratory symptoms in the first case. A 120 cc urinoma was drained in the second case but the infant died of pulmonary hypoplasia at 22 h of age. This report emphasizes the importance of aspirating or draining the urinoma in an attempt to treat the newborn's respiratory insufficiency.

Drainage↗
PubMed1990

A new perspective of microbial survival and dissemination in a prospectively contaminated air-fluidized bed model.

A major concern of users of air-fluidized beds has been the possibility that such beds might be a source of microbial contamination. The purpose of this series of prospective, controlled experiments was to measure quantitatively the dissemination and survival of Bacillus subtilis, a species of bacterium that forms desiccation-resistant spores, as it was associated with circulating and clumped microbeads after challenge in an air-fluidized bed operating under decontamination conditions of heating at 48 degrees C and microbead agitation by an air flow of 100% at 110 cu ft/min. Microbead samples collected after B. subtilis challenge from predesignated depths and locations within the air-fluidized bed at 0.25, 1, 2, 4, 24, and 48 hours were assayed for colony-forming units (CFU) of challenge bacteria by end point dilution and streak-plate assays. Results of three experiments with an average challenge of 1110 CFU of B. subtilis per gram of microbeads indicated that no more than 0.46 CFU of B. subtilis per gram of circulating microbeads and 0.78 CFU per gram of clumped microbeads were detected after 24 to 48 hours at decontamination conditions. Few microbes were detected during three control (sterile water) challenges of the air-fluidized bed operating at 33 degrees C with 95% to 100% air flow. This study has demonstrated that an air-fluidized bed operating at the described decontamination conditions for 24 to 48 hours caused significant decreases, averaging a thousandfold per gram, in levels of microbead-associated challenge bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Movements↗
PubMed1990

Importance of prenatal detection of hydronephrosis of the upper pole.

To determine the impact of prenatal detection on neonates with hydronephrosis of the upper pole of a duplex collecting system, we reviewed 40 such cases seen between June 1982 and April 1989. This six-per-year rate contrasts with fewer than one case per year that was seen at our hospital from 1947 to 1977. Nineteen patients had an ectopic ureterocele, and 21 had an ectopic ureter without a ureterocele. Thirty-three (83%) were girls. Thirty-three cases were discovered because of abnormal findings on a prenatal sonogram, and 20 of those infants were asymptomatic. In the 33 patients whose prenatal sonographic findings were abnormal, the sonogram was diagnostically precise for hydronephrosis of the upper pole of a duplex collecting system in only 39%. This imprecision did not adversely affect management or outcome. Postnatal sonography modified the prenatal diagnosis in 75% of these 33 patients. Voiding cystourethrography was the most sensitive and precise imaging technique for detecting both ureterocele and reflux. Lower pole reflux was almost twice as common when an ectopic ureterocele was present (63%) than when one was not (33%). Prenatal sonographic detection of hydronephrosis of the upper pole of a duplex collecting system decreased the proportion of neonates presenting with urinary tract infection and urosepsis because of prophylactic antibiotics initiated at birth and continued until surgical correction. Precise prenatal diagnosis was not needed for effective surgical treatment.

Humans↗
PubMed1989

Catalepsy induced by combinations of ketamine and morphine: potentiation, antagonism, tolerance and cross-tolerance in the rat.

Previous studies demonstrated that both ketamine and morphine induced analgesia and catalepsy in the rat. Pre-treatment with ketamine produced cross-tolerance to morphine, whereas pretreatment with morphine did not induce cross-tolerance to ketamine but rather augmented the cataleptic response; this augmentation was attributed to residual morphine in the brain. The present studies explored the duration of the loss of righting reflex induced by sub-effective doses of ketamine and morphine, administered simultaneously. There was mutual potentiation between sub-effective doses of ketamine and morphine, but sub-effective doses of ketamine partly antagonized fully-effective doses of morphine. Latency to the loss of righting reflex, rigidity and behavior on recovery, reflected the relative predominance of ketamine or morphine in each combination. Naloxone inhibited the induced cataleptic effects. The degree and time course of development of tolerance to daily administration of sub-effective dose combinations of ketamine and morphine were similar. Rats, tolerant to ketamine-dominant combinations, were cross-tolerant to both drugs, while those tolerant to morphine-dominant combinations were cross-tolerant to morphine but showed either no cross-tolerance or an augmented response to ketamine. While the mutual potentiation, antagonism and tolerance suggest common mechanisms for the induced catalepsy, differences in latency, rigidity and behavior, asymmetry of cross-tolerance and a widely-different ID50 for naloxone would argue against an action at a single opioid site.

Animals↗
PubMed1989

Comparison of isomers of ketamine on catalepsy in the rat and electrical activity of the brain and behavior in the cat.

The present study compared the relative potency and efficacy of the two isomers of ketamine on the duration of catalepsy (loss of righting reflex) in female rats and on the behavior and electroencephalogram of cats. In the rat, at small doses, the S(+) isomer was more potent than the R(-) isomer or racemic ketamine, while at larger doses, the S(+) isomer and the racemate were equipotent and the R(-) isomer was significantly less potent. Tolerance developed rapidly to the effects of either isomer and both were equally cross-tolerant to racemic ketamine. Sub-effective doses of morphine significantly increased the potency of S(+), R(-) and racemic ketamine on the duration of catalepsy. Sub-effective doses of either isomer augmented the duration of catalepsy, induced by small doses of morphine, but reduced that of large doses. In cats, there was a parallel time course and progression of behavioral and electroencephalographic states in response to equal total doses of either racemic ketamine, an artificial 50:50 mixture of S(+) and R(-) isomers, or the S(+) isomer alone; approximately equivalent effects required twice the dose of the R(-) isomer. It is concluded that there is a common site of action for the two isomers, but there is also a stereospecific difference in potency, as regards the induction of catalepsy in the rat and behavioral and electroencephalographic effects in the cat. Stereospecificity was not apparent in the development of tolerance, cross-tolerance or the augmentation of the response to morphine.

Animals↗