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Biomedical subjects

J Arena

Publications and source records attributed to J Arena.

At least 19 recordsLinked to original sources
PubMed2005

Skin to calcaneus distance in the neonate.

BACKGROUND: Current recommendations for obtaining blood from neonates advise avoidance of the midline area of the heel and are based on postmortem studies. OBJECTIVE: Because of the potential pain and tissue damage from repeated heel pricking in the same area, to investigate using ultrasonography whether the distance from skin to calcaneus is less at the midline than at the borders. METHODS: One hundred consecutive healthy preterm and 105 consecutive healthy term neonates were studied 48-72 hours after delivery. The skin to perichondrium distance (SPD) was measured on two occasions by ultrasound at the external, midline, and internal areas of the heel. FINDINGS: Mean SPD was 0.2 mm less at the midline than at the other sites. The proportion of measurements <3 mm at any of the three sites was the same. Depth was <3 mm in less than 3% of the term and approximately 20% of the preterm infants. The SPD correlated only with gestational age. Of children <33 weeks gestational age, 38% had an SPD <3 mm compared with 8% of older preterm infants. The proportions of preterm infants of > or = 33 weeks gestation and term infants with an SPD <3 mm were similar (8% v 3%). INTERPRETATION: With the use of automated lancets of 2.2 mm length or less, the whole heel plantar surface is safe for obtaining blood in term and preterm infants of > or = 33 weeks gestation. This means that soft tissue damage and pain from repeated pricking in the same area can be reduced.

Anthropometry↗
PubMed2000

Nonplatelet effects of aspirin during acute coronary occlusion: electrophysiologic and cation alterations in ischemic myocardium.

BACKGROUND: Mortality after acute myocardial ischemia has been reduced by aspirin (ASA) but mechanisms other than the antiplatelet effect have not been established. This article evaluates an antiarrhythmic action during sympathetic stimulation in the intact anesthetized dog with and without ischemia. METHODS AND RESULTS: The ventricular fibrillation threshold (VFT) was examined before and after epinephrine (E) in normals (group I). A VFT reduction during E was normalized after 1 week of ASA (P<.01). Regional myocardial ischemia for 1 hour resulted in similar hypoperfusion in controls of group II and after ASA. Action potential responses in isolated superfused ischemic tissue showed prolonged repolarization (APD90) in response to E, which was normalized after ASA (P<.01). To assess the antiarrhythmic role of the anion in group III, Na salicylate was given. During 1 hour of ischemia, the VF incidence was reduced and cation abnormalities diminished in ischemic myocardium compared with untreated ischemia. CONCLUSIONS: ASA antagonizes the reduction of the VFT induced by catecholamine in normals as well as the repolarization abnormality elicited by E during acute ischemia. The salicylate anion appears to be the active component in view of the efficacy in preventing VF during the early ischemic period.

Action Potentials↗
PubMed1999

XLMR genes: update 1998.

Since the Seventh Fragile X and XLMR Mental Retardation (XLMR) Workshop in 1995, the genes for Coffin-Lowry, Mohr-Tranebjaerg, and Opitz G/BBB syndromes have been cloned. Jensen syndrome has been found to be allelic to Mohr-Tranebjaerg. Twenty new XLMR syndromes and metabolic or neuromuscular disorders have been reported. Twenty-four new localizations have been established, including five in previously reported conditions (FG, Carpenter, Arts, OPA2, and OFD1). The number of families with nonspecific XLMR that have been reported has continued to increase; 58 families or loci are now known. Eighteen new families with nonspecific mental retardation (MRX) have been reported. Two of them, however, were subsequently found to have mutations in the RABGDIA gene, which codes for a GDP-dissociation inhibitor for RAB proteins. In total, 41 more entries have been added to the X chromosome map of XLMR. The total number of known syndromes and MRX families has increased to 178. Of the 120 known XLMR disorders, 53 have been mapped, and 22 have been cloned. Assuming that at least 10 loci are necessary to account for the 58 families with MRX, the total number of XLMR loci counted so far would be 130. Although it is likely that many of the disorders will eventually prove to be allelic, it is not possible at present to determine the precise number of loci for nonspecific XLMR.

Humans↗
PubMed1999

Genetic and phenotypic aspects of phenylalanine hydroxylase deficiency in Spain: molecular survey by regions.

We present an extensive study of the genetic diversity of phenylalanine hydroxylase deficiency in the Spanish phenylketonuria population. We have analysed 195 PKU patients by DGGE analysis identifying 67 different mutations which represent 89% of the total mutant chromosomes. Seventeen mutations first described in Spain have not yet been detected elsewhere; ten of these are reported here for the first time. The clinical significance of this high genetic heterogeneity was examined by analysing the genotype-phenotype correlations, mainly focusing on the mild hyperphenylalaninaemia (MHP) phenotype. The genotypes found in a group of 93 MHP patients, the largest analysed so far, are described in detail, as well as the relative frequencies of the MHP mutations identified. From the total pool of mutations, 27 can be considered severe, 18 can be defined as mild and 13 as associated with MHP. The prevalent mutations correspond to one severe mutation (IVS10nt-11), one MHP mutation (A403V) and two mild mutations (165T and V388M). The high frequency of mutations with a low degree of severity can explain the relatively higher prevalence of MHP and mild PKU phenotypes in Spain compared with NOrthern European populations. We have looked at the geographical distribution in Spain of the more common mutations, finding evidence of local mutation clustering, which could be the result of differences in the ethnic background and/or of genetic drift within each region.

Genetic Testing↗
PubMed1998

Clinical and physiological effects of stereotaxic bilateral amygdalotomy for intractable aggression.

The amygdala is thought to be an important neural structure underlying the "fight-or-flight" response, but information on its role in humans is scarce. The clinical and psychophysiological effects of amygdalar destruction were studied in 2 patients who underwent bilateral amygdalotomy for intractable aggression. After surgery, both patients showed a reduction in autonomic arousal levels to stressful stimuli and in the number of aggressive outbursts, although both patients continued to have difficulty controlling aggression. The "taming effect" reported after bilateral amygdalar destruction may be due to the amygdala's inadequate processing of perceived threat stimuli that would normally produce a fight-or-flight response.

Adult↗
PubMed1997

Do you know what a dietetic technician can do? A focus on clinical technicians and their expanded roles and responsibilities.

Dietetic technicians, registered, play a key role in providing quality, cost-effective client care and foodservice management and are guided by the mission statement of the American Dietetic Association to promote optimal nutrition, health, and well-being. Many organizations use dietetic technicians to complete the screening and/or basic level assessments. The dietetic technician also can assist with patient monitoring and complete such tasks as calculating and documenting calorie counts, providing basic diet instruction, monitoring diet consumption and compliance, and determining tolerance of nutritional supplements. Since the last role delineation study was conducted, dietetic technicians have expanded into many different work settings, and practice roles have changed accordingly.

Allied Health Personnel↗
PubMed1996

Structural relations between collagen and mineral in bone as determined by high voltage electron microscopic tomography.

Aspects of the ultrastructural interaction between collagen and mineral crystals in embryonic chick bone have been examined by the novel technique of high voltage electron microscopic tomography to obtain three-dimensional information concerning extracellular calcification in this tissue. Newly mineralizing osteoid along periosteal surfaces of mid-diaphyseal regions from normal chick tibiae was embedded, cut into 0.25 microns thick sections, and documented at 1.0 MV in the Albany AEI-EM7 high voltage electron microscope. The areas of the tissue studied contained electron dense mineral crystals associated with collagen fibrils, some marked by crystals disposed along their cylindrically shaped lengths. Tomographic reconstructions of one site with two mineralizing fibrils were computed from a 5 degrees tilt series of micrographs over a +/- 60 degrees range. Reconstructions showed that the mineral crystals were platelets of irregular shape. Their sizes were variable, measured here up to 80 x 30 x 8 nm in length, width, and thickness, respectively. The longest crystal dimension, corresponding to the c-axis crystallographically, was generally parallel to the collagen fibril long axis. Individual crystals were oriented parallel to one another in each fibril examined. They were also parallel in the neighboring but apparently spatially separate fibrils. Crystals were periodically (approximately 67 nm repeat distance) arranged along the fibrils and their location appeared to correspond to collagen hole and overlap zones defined by geometrical imaging techniques. The crystals appeared to be continuously distributed along a fibril, their size and number increasing in a tapered fashion from a relatively narrow tip containing smaller and infrequent crystals to wider regions having more densely packed and larger crystals. Defined for the first time by direct visual 3D imaging, these data describe the size, shape, location, orientation, and development of early crystals in normal bone collagen. The results suggest that platelet-shaped crystals are arranged in channels or grooves which are formed by collagen hole zones in register and that crystal sizes may exceed the dimensions of hole zones. Such data agree with those from mineral-matrix interaction in normally calcifying avian tendon obtained by similar high voltage tomographic means, but in addition they indicate a possible gradual and continuous deposition of crystals in collagen of bone unlike tendon and imply that individual collagen fibrils in local regions of osteoid are organized such that they all may be aligned in a coherent manner.

Animals↗
PubMed1992

Extracellular vesicles of calcifying turkey leg tendon characterized by immunocytochemistry and high voltage electron microscopic tomography and 3-D graphic image reconstruction.

To gain insight into the structure and possible function of extracellular vesicles in certain calcifying vertebrate tissues, normally mineralizing leg tendons from the domestic turkey, Meleagris gallopavo, have been studied in two separate investigations, one concerning the electron microscopic immunolocalization of the 66 kDa phosphoprotein, osteopontin, and the other detailing the organization and distribution of mineral crystals associated with the vesicles as determined by high voltage microscopic tomography and 3-D graphic image reconstruction. Immunolabeling shows that osteopontin is related to extracellular vesicles of the tendon in the sense that its initial presence appears coincident with the development of mineral associated with the vesicle loci. By high voltage electron microscopy and 3-D imaging techniques, mineral crystals are found to consist of small irregularly shaped particles somewhat randomly oriented throughout individual vesicles sites. Their appearance is different from that found for the mineral observed within calcifying tendon collagen, and their 3-D disposition is not regularly ordered. Possible spatial and temporal relationships of vesicles, osteopontin, mineral, and collagen are being examined further by these approaches.

Animals↗
PubMed1986

Arrhythmia susceptibility and myocardial composition in diabetes. Influence of physical conditioning.

Abnormal myocardial composition in diabetes mellitus has been described, but the effects on ventricular vulnerability have not been defined. We have assessed the susceptibility to arrhythmias in a canine model after 1 yr of mild diabetes induced by alloxan. Since physical conditioning can affect metabolic abnormalities in diabetes, this intervention has also been evaluated. Group 1 served as controls and groups 3 and 4 were diabetic. Animals in the latter group as well as nondiabetic controls of group 2 were exercised on a treadmill for the last 8 mo of the experiment. After 1 yr, anesthesia was induced with chloralose for vulnerability studies. The ventricular fibrillation threshold of 24.4 +/- 1.9 mA in group 3 was significantly less than in normals (45.1 +/- 2.2). Spontaneous arrhythmias were also more prevalent in diabetics during acute ischemia (group 3-A). Increased ventricular vulnerability after epinephrine infusion was present in the sedentary diabetes despite normal ventricular function responsiveness. In a superfused preparation of myocardium, resting membrane potential and action potential amplitude were normal in diabetics, and beta-adrenergic stimulation shortened repolarization more than in controls. Myocardial collagen concentrations, which included an interfibrillar distribution on morphologic examination, were increased in group 3. In the trained diabetics of group 4 the basal vulnerability thresholds and responses to epinephrine were normal. While myocardial collagen levels were normal, cholesterol and triglyceride increments persisted. Thus, in mild experimental diabetes, enhanced susceptibility to arrhythmias exists; this susceptibility may be based on a combination of nonhomogenous collagen accumulation affecting local conduction and increased electrophysiologic sensitivity to catecholamines.

Action Potentials↗
PubMed1985

[Real-time cerebral echography in meningitis in the newborn infant and infants].

We report echographic findings in 17 patients with meningitis of which 16 were bacterial and the remaining one was due to toxoplasma. The signs more frequently observed have been ventricular dilatation and thickening of cortical sulci with increased echogenicity. Emphasis is made on the usefulness of realtime brain ultrasonography for monitoring of certain meningitis during the acute phase as well as for detection of sequelae later on the clinical course. One of our patients had tuberculous meningitis, and as far as we know, our sonographic follow-up is the first reported so far in this disease.

Cerebral Ventricles↗
PubMed1985

[Problems of neonatal screening for hypothyroidism in the very low birth-weight neonate].

21,013 newborns were screened on the first year of a neonatal screening program on congenital hypothyroidism in the Basque Community. The evaluation of the results showed some points of interest. One of them, would be the high analytical retesting rate needed in the screening of very low-birth weight children. The rate decreased with increasing birth-weight. Forty per cent of the children with a birth-weight lower than 1,000 gr needed retesting. The rate decreased to 7.7% at birth-weights between 1,001 and 1,500 gr, to 2% at birth weights between 1,501 and 2,500 gr and only to 0,42% at birth-weights higher than 2,501 gr. The consequences of these results are discussed.

Congenital Hypothyroidism↗
PubMed1985

[Repercussion of the application of povidone-iodine to the umbilical stump on thyroid function of the neonate at term].

We have studied blood TSH and T4 5-7 days after birth in 356-healthy newborns whose umbilical stump had been treated with 10% povidone-iodine. The prevalence of high TSH levels (above 20 microU/ml) was higher in this group than in the general population (3.09% vs 0.417%, p less than 0.001), and so was the rate of transient hypothyroidism (2.73% vs 0.25%, p less than 0.001). Both differences were related to the number of applications of iodine given. All children were found to be normal at retesting one week later. This study adds new evidence on the high vulnerability of newborn thyroid to small iodine doses and further discourages the use of povidone-iodine for the care of umbilical stump.

Administration, Topical↗
PubMed1984

[Encapsulated adrenal hemorrhage in the newborn infant. Study of 8 cases].

We report 8 cases of neonatal encapsulated adrenal haemorrhage clinically suspected and diagnosed in living newborns. Six of them were right-sided (75%), and only 2 left-sided (25%). Clinical manifestations were limited to the palpation of a flank mass and or the presence of jaundice of unknown cause. We comment on the etiology clinical picture, diagnosis, course and treatment of adrenal haemorrhage pointing out to the importance of ultra-sonography for diagnosis and follow-up, as opposed to IVP. In four patients we could sustain the presumption of normal adrenal function by means of a rapid ACTH stimulation test.

Adrenal Gland Diseases↗
PubMed1982

[Omphalosite monster (acardius acephalus). Apropos of a case].

The omphalosite monster is acardiac (deprived of heart) and his survival is only possible through intrauterine life because of the umbilical vascular connections with his healthy monochorionic twin brother who takes in charge the circulation of both. We report one typical case of the acephalic variety in which all structures derived from the fetal cephalic fold were absent. Its only eventual clinical interest is limited to the prenatal radiological diagnosis and the neonatal onset of congestive heart failure in the healthy twin, a fact which must be known in order to establish an early treatment. On this occasion, we briefly review the current knowledge about this very rare form of monstrosity.

Abnormalities, Severe Teratoid↗
PubMed1982

[Real-time ultrasonography in neonatal diagnosis].

Real time ultrasonography is a diagnostic technique very widely used in pediatrics and with specific applications in neonatology. Bedside its use in Neonatal I.C.U. it has many interesting aspects for intraabdominal and intracranial pathology. In some particular conditions this procedure can be the first diagnostic tool. Conventional X-rays can be performed after sonographic data have been analyzed.

Abdomen↗
PubMed1979

[Wiedemann-Beckwith syndrome heredity pattern (author's transl)].

The authors report a sibship of four members (two male and two female)displaying the entire clinical picture of the Wiedemann-Beckwith syndrome. There was no consanguinity and no antecedents could be found in a three-generation search. On this occasion, a review is made of what is known about the Wiedemann-Beckwith syndrome concerning its hereditary pattern, which can currently be considered as autosomal dominant with variable expressivity and incomplete penetrance, instead of recessive as it was formerly accepted This heredity pattern must be known in order to provide an accurate genetic advise.

Abnormalities, Multiple↗