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Biomedical subjects

R Greenberg

Publications and source records attributed to R Greenberg.

At least 145 records · Page 8Linked to original sources
PubMed1984

Leave-takings and reunions of infants, toddlers, preschoolers, and their parents.

The leave-taking and reunion behaviors of infants, toddlers, preschoolers, and their parents were observed as the children were "dropped off" and "picked up" at their nursery school each day. On arrival at their classroom, infants and toddlers related primarily to their parents, whereas preschoolers related to their teachers. Girls more frequently engaged in interaction with their teachers, and boys more frequently approached the children's play activities. Distress behaviors during the parents' departures were most frequently shown by toddlers, and the toddlers' parents hovered about them and " sneaked out of the room" more frequently. Children dropped off by mothers versus fathers showed more attention-getting behavior and crying, and mothers versus fathers engaged in more "distracting-the-child" behaviors and showed a longer latency to leave the classroom. During the second semester of observations parents and children spent less time relating to each other during leave-taking, children protested the departures less frequently, and the parents left the classroom more quickly. Regression analyses on distress behaviors during leave- takings and ambivalent behavior during reunions suggested that parent behaviors such as verbal explanation, distracting the child, latency to leave, and " sneaking out of the room" were correlated with children's distress and leave-taking distress was related to ambivalent behavior at reunion.

Attitude↗
PubMed1983

Bladder mucosal grafts: experimental use as a ureteral substitute and observation of certain physical properties.

Free bladder mucosal grafts were evaluated as material for ureteral substitution. Surgical replacement of the ureter with free bladder mucosa in dogs demonstrates the feasibility of this technique. Graft patency with preservation of urothelial lining and regeneration of smooth muscle was observed. Physical properties observed during the experiment indicate a good potential for long term preservation of the graft material.

Animals↗
PubMed1982

A switch region inversion contributes to the aberrant rearrangement of a mu immunoglobulin heavy chain gene in MPC-11 cells.

We describe the unique features of an aberrantly rearranged mu immunoglobulin heavy chain gene isolated from MPC-11 cells (a gamma 2b producing Balb/c plasmacytoma). A novel rearrangement has occurred 1.5 Kb 5' of the MPC-11 mu gene (denoted 18b mu) resulting in the deletion of the majority of the repetitive switch region (S mu) and 5' flanking DNA including the Joining (JH) sequences. The remainder (275 bp) of the S mu repeat has undergone a complete sequence inversion. DNA sequences 5' of the inverted S mu sequence do not resemble Variable (VH), Diversity (D), JH or their conserved flanking sequences. A DNA sequence localized 5' of the inverted S mu sequence, (p18b mu-1.4) detects a small family of homologous sequences in Balb/c DNA. The 18b mu-1.4 like sequences lack homology to S mu, exhibit flanking sequence polymorphisms in 5 out of 6 inbred mouse strains and undergo partial or complete deletion in 5 out of 10 plasmacytomas tested. Two 18b mu-1.4 homologous sequences display a higher copy number in C57Bl/6, AL/N and CAL9 mouse strains.

Animals↗
PubMed1982

Discrimination and imitation of facial expression by neonates.

Human neonates (average age, 36 hours) discriminated three facial expressions (happy, sad, and surprised) posed by a live model as evidenced by diminished visual fixation on each face over trials and renewed fixations to the presentation of a different face. The expressions posed by the model, unseeen by the observer, were guessed at greater than chance accuracy simply by observing the face of the neonate, whose facial movements in the brow, eyes, and mouth regions provided evidence for imitation of the facial expressions.

Behavior↗
PubMed1982

Liquid chromatographic determination of caffeine in biologic fluids.

A high-performance liquid chromatographic procedure was developed for the determination of caffeine in various biologic fluids and coffee. A reversed-phase column and UV detection at 254 nm were used to obtain a sensitivity of 0.1 microgram/ml caffeine in serum and saliva using a sample volume of 0.1 ml. Caffeine metabolites and commonly ingested xanthines do not interfere with the assay. The within-day coefficients of variation were 9.8 and 9.9% at plasma caffeine concentrations of 2 and 10 micrograms/ml, respectively. The day-to-day coefficients of variation were 6.8 and 6.6% at plasma caffeine concentrations of 2 and 10 micrograms/ml, respectively. Serum and saliva caffeine concentrations were determined following a single oral dose of coffee and an intravenous infusion of caffeine in one subject. Computer estimates of caffeine pharmacokinetic parameters in one subject are in excellent agreement with previously published values.

Caffeine↗
PubMed1982

Thromboxane A2 mediated bronchoconstriction in the anesthetized guinea pig.

Arachidonic acid-induced platelet aggregation has been shown to be selectively antagonized by the thromboxane A2 synthetase inhibitor SQ 80,338 or by the thromboxane A2 receptor antagonist SQ 24,775. Experiments were done to see what effect these two compounds would have on the bronchoconstrictor response to various agents in the anesthetized guinea pig. Increases in pulmonary resistance and decreases in dynamic compliance were taken as an index of bronchoconstriction. Both SQ 80,338 (0.3-10.0 mg/kg) and SQ 24,775 (0.1-1.0 mg/kg) administered i.v. caused dose-related inhibitions of arachidonate-induced bronchoconstriction. SQ 80,338 (3.0 and 10.0 mg/kg) also inhibited bradykinin-induced bronchoconstriction in the presence of beta-adrenergic blockade. These same doses of SQ 80,338 and SQ 24,775 did not alter either histamine- or antigen-induced bronchoconstriction. SQ 80,338 (10.0 micrograms/ml) prevented arachidonate-induced release of TXA2 from the isolated perfused guinea pig lung while SQ 24,775 (1.0 microgram/ml) antagonized the contraction of the isolated rat aorta induced by 9,11,AZO-PGH2. These results suggest that both arachidonate and bradykinin-induced bronchoconstriction are mediated through the generation of TXA2, while histamine- and antigen-induced bronchoconstriction are not.

Anesthesia↗
PubMed1982

Complete amino acid sequence of bovine beta 2-microglobulin.

beta 2-Microglobulin has been isolated and crystallized from bovine colostrum and represents the only crystalline form of this protein reported. The complete sequence of bovine beta 2-microglobulin was determined using only one proteolytic enzyme, Staphylococcus aureus V8 protease. Automated degradation of the intact molecule and two large peptides produced by enzymic digestion provided unequivocal placement of all residues. Bovine beta 2-microglobulin, molecular weight 11,630, contains 98 residues as compared with 99 for the human, rabbit, guinea pig, and murine proteins. The valine residue at position 49 in all the aforementioned species is deleted in the bovine variant. This crystalline protein is also uniquely characterized by three di-prolyl sequences in the first third of the molecule. beta 2-Microglobulin is a highly conserved protein, and in a comparison of absolute amino acid sequence differences among species, bovine beta 2- microglobulin ranges from a low of 24 substitutions as compared with the rabbit homologue and 26 for human to 32 for mouse and guinea pig.

Amino Acid Sequence↗
PubMed1982

beta 2-Microglobulin and its relationship to the immune system.

beta 2-Microglobulin has been isolated from several species, but only bovine beta 2-microglobulin, previously known as lactollin, has been crystallized. An improved method for its isolation from colostrum is described. The bovine homologue exhibits a concentration-dependent aggregation behavior. beta 2-Microglobulin is related to both immune and histocompatibility antigen systems. It exhibits homology with the constant domains of the immunoglobulin-G light and heavy chains and is an integral part of histocompatibility antigens bound to cell surface. beta 2-Microglobulin also occurs in the free state in various body fluids including milk and colostrum. The possible relationship of elevated free beta 2-microglobulin of pathological conditions is suggested for future research.

Amino Acid Sequence↗
PubMed1982

Nonnutritive sucking during tube feedings: effects on preterm neonates in an intensive care unit.

Preterm neonates (mean 32 weeks' gestation, 1,300 gm birth weight) were provided a pacifier for nonnutritive sucking during tube feedings in the intensive care nursery. Their clinical course, subsequent bottle feeding behavior, and performance on the Brazelton Neonatal Behavior Assessment scale were compared with those of control group infants. The infants provided with pacifiers averaged 27 fewer tube feedings, started bottle feeding three days earlier, averaged a greater weight gain per day, and were discharged eight days earlier for an average hospital cost savings of approximately $3,500. Formula intake was similar for the two groups, although nurses appeared to provide more feeding stimulation for the control infants. On the Brazelton scale, the infants provided with pacifiers showed weak reflexes more frequently. Increased restfulness and diminished activity level in these infants may have contributed to the appearance of weak reflexes. The consistency between these findings and those of previous investigators suggests that the provision of a pacifier for nonnutritive sucking during tube feedings may be a cost-effective form of intervention.

Body Weight↗
PubMed1982

Effects of parent training on teenage mother and their infants.

Parent training was provided for 80 low-income, black teenage mothers during their infants' first six months. Half of the mothers were visited biweekly in their homes to be instructed in caregiving and in sensorimotor and interaction exercises, and half were trained as CETA (Comprehensive Employment Training ACT)-paid, teacher's aides in a medical school infant nursery that provided care for their infants and infants of medical faculty. Growth and development during the first two years were superior for the infants whose mothers received training, particularly those who received paid parent training as teacher's aides in the infant nursery. Repeat pregnancy rates were lower and return to work/school rates were higher for the infant nursery mothers, most of whom subsequently pursued nurse's aide training.

Adolescent↗