DAPI (4',6-diamidino-2-phenylindole) is a DNA-specific probe which forms a fluorescent complex by attaching in the minor grove of A-T rich sequences of DNA. It also forms nonfluorescent intercalative complexes with double-stranded nucleic acids. The physicochemical properties of the dye and its complexes with nucleic acids and history of the development of this dye as a biological stain are described. The application of DAPI as a DNA-specific probe for flow cytometry, chromosome staining, DNA visualization and quantitation in histochemistry and biochemistry is reviewed. The mechanisms of DAPI-nucleic acid complex formation including minor groove binding, intercalation and condensation are discussed.

/pdf/dapi-a-dna-specific-fluorescent-probe-36ijcd1br9.pdf

DAPI: a DNA-Specific Fluorescent Probe

Hepatitis B vaccines.

Down syndrome, the phenotypic expression of human trisomy 21, is presumed to result from a 1.5-fold increase in the expression of the genes on human chromosome 21. As an approach to the development of an animal model for Down syndrome, several strains of transgenic mice that carry the human Cu/Zn-superoxide dismutase gene have been prepared. These animals express the transgene in a manner similar to that of humans, with 0.9- and 0.7-kilobase transcripts in a 1:4 ratio, and synthesize the human enzyme in an active form capable of forming human-mouse enzyme heterodimers. Cu/Zn-superoxide superoxide dismutase activity is increased from 1.6- to 6.0-fold in the brains of four transgenic strains and to an equal or lesser extent in several other tissues. These animals provide a unique system for studying the consequences of increased dosage of the Cu/Zn-superoxide dismutase gene in Down syndrome and the role of this enzyme in a variety of other pathological processes.

Transgenic mice with increased Cu/Zn-superoxide dismutase activity: animal model of dosage effects in Down syndrome.

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

/pdf/nutrient-requirements-for-preterm-infant-formulas-4ixx0nh1x1.pdf

Nutrient Requirements For Preterm Infant Formulas

This review explores evidence that free radicals might be involved in various human disease processes. Such involvement is difficult to prove because direct evidence is often lacking and is based on animal models of the disease process. Evidence for free radical involvement includes demonstrating abnormal free radical production in the disease, finding that deliberately applying free radical-producing systems into the cellular locus responsible for the disease reproduces its manifestations, and showing that free radical scavengers control facets of the disease process. Confirmation of free radical involvement in a particular disease may have clinical relevance, inasmuch as clinically applicable techniques are currently being developed to remove free radicals from cellular sites where they are injurious and, in other situations such as chemotherapy, techniques or drugs that produce free radicals are available to destroy harmful cells.

Free Radicals in Medicine. II. Involvement in Human Disease

Prevention of bronchopulmonary dysplasia by administration of bovine superoxide dismutase in preterm infants with respiratory distress syndrome

Patent ductus arteriosus is common among premature neonates, especially those with birth weights less than 1,500 g. In vitro, room light inhibits the contraction of immature piglet's ductal rings. Because phototherapy is used frequently from the first days of life to treat jaundice in preterm neonates, we compared the occurrence of patent ductus arteriosus among premature infants exposed to this intense light source with those whose chests were shielded. Seventy-four babies with respiratory distress syndrome were randomly assigned to either a treatment group (chest shielded with aluminum foil while on phototherapy, 36 babies) or control group (no shield, 38 babies). All were on radiant warmers, received mechanical ventilation for respiratory distress syndrome, and phototherapy (Air Shields model PTU 78-1) from day 1 of life. Irradiance was maintained at greater than 4.0 microW/cm2/nm in all cases. Although both groups had similar birth weights, gestational ages, severity of respiratory distress syndrome, intravenous fluid intake, and duration of phototherapy, the incidence of patent ductus arteriosus was significantly less in the shield group (shield 11/36 v No shield 23/38; P = .009). Patent ductus arteriosus murmurs developed in shielded patients at a later date, they required less vigorous treatment (ie, indomethacin), and they had shorter hospitalizations (74 v 85 days; P less than .05). The significant reduction of patent ductus arteriosus with shielding suggests that phototherapy may play a role in the occurrence of patent ductus arteriosus in premature infants. Shielding may be a practical method to decrease this common complication should this initial observation be confirmed.

Phototherapy effect on the incidence of patent ductus arteriosus in premature infants: prevention with chest shielding.

NEONATAL infection with hepatitis B is potentially a severe disease1 , 2 and may later cause a large number of adults to be chronically infected with hepatitis B surface antigen HBsAg.3 Retrospective studies indicate that severe or fatal infection in the neonate is due to transmission early in the neonatal period.1 , 2 Two families have been described in which fatal hepatitis B infection developed in successive children.2 , 4 Both mothers were chronic carriers of HBsAg. In a third family fatal neonatal hepatitis B infection developed in four of six children of a chronic carrier.5 We report here a family in which such a fatal . . .

Prevention of neonatal hepatitis B infection by high-dose hepatitis B immune globulin.

Oxidant injury and release of proteolytic enzymes in prematures with respiratory distress syndrome (RDS), who are treated with ventilators and oxygen, have been postulated as possible causes of bronchopulmonary dysplasia (BPD). The premature may be at particular risk due to low levels of antiproteases, such as alpha-1-proteinase inhibitor (alpha 1PI), and antioxidants, such as ceruloplasmin (CER). Both alpha 1PI and CER deficiencies have been correlated with the severity of RDS. We studied serial alpha 1PI activity as measured by trypsin inhibitory capacity (TIC) and CER in the serum 27 prematures who required ventilator therapy for RDS. Serum TIC values for day 1 were significantly lower (0.34 vs. 0.92 mg inhibited/ml of sample) in the 13 patients who developed BPD compared to the 14 who did not. No significant differences were seen on succeeding days. No significant differences in CER were seen, although both groups had levels 33-50% of adult normals (11.3 vs 9.3 mg/dl). Other significant variables included birthweight (p less than 0.005), severity of RDS (p less than 0.03), and gestational age (p less than 0.03). One way analysis of variances demonstrated day 1 TIC to be the most significant variable (p less than 0.0001), followed by weight (p less than 0.007), severity RDS (p less than 0.04), and gestational age (p less than 0.03). CER levels were not a significant variable. A formula utilizing unstandardized canonical discriminant function including day 1 TIC, birthweight, severity of RDS, and gestational age was 100% sensitive and 85% specific in the prediction of BPD for the original study group. In an additional 25 consecutive admissions with severe RDS of whom 18 survived, the formula was 100% sensitive (6/6) and 75% specific (9/12).(ABSTRACT TRUNCATED AT 250 WORDS)

Serial trypsin inhibitory capacity and ceruloplasmin levels in prematures at risk for bronchopulmonary dysplasia.

• The effect of modified gowning techniques in a neonatal intensive care unit was evaluated. During alternate two-month intervals, no gowns were worn over street clothes in patient care areas by staff or visitors. Mortality and infection rates during these "modified" gowning intervals were the same as during the gowning periods. However, the incidence of necrotizing enterocolitis was significantly greater in the modified gowning period (7/353) than in the gowning periods (1/371). An expansion of this one-year study to include another year showed an even greater effect. The prevalence of bacteria at three anatomic sites (nares, umbilicus, and groin) on days 2, 4, 7, 10, 14, 21, and 28 of hospitalization was comparable between those studied during modified gowning and gowning intervals. Exceptions were the significantly increased prevalence of Staphylococcus epidermidis in the groin (days 21 and 28) during gowning and S aureus in the nares (day 28) during modified gowning periods. ( Am J Dis Child 1981;135:650-652) Environmental controls are routinely used in neonatal intensive care units (NICUs) to decrease the likelihood of superficial or systemic infections in high-risk cases. However, certain controls may limit the frequency of medical and family visits, add to expense, and are not of proven value in the control of infection. We previously demonstrated 1 no adverse effect on mortality, infection rate, or prevalence of bacterial flora related to a "no gowning" procedure in neonates cared for in incubators (Isolettes) or open cribs. However, gowns were always worn when the incubator's hood was open. The present study

Ramesh Jhaveri

Papers

Prevention of bronchopulmonary dysplasia by administration of bovine superoxide dismutase in preterm infants with respiratory distress syndrome

Phototherapy effect on the incidence of patent ductus arteriosus in premature infants: prevention with chest shielding.

Prevention of neonatal hepatitis B infection by high-dose hepatitis B immune globulin.

Serial trypsin inhibitory capacity and ceruloplasmin levels in prematures at risk for bronchopulmonary dysplasia.

Evaluation of Modified Gowning Procedures in a Neonatal Intensive Care Unit