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Biomedical subjects

K Frantz

Publications and source records attributed to K Frantz.

12 recordsLinked to original sources
PubMed2001

High-technology breastfeeding.

When there is interference with the natural process of breastfeeding, breastfeeding technology may be useful in supporting women to initiate and continue breastfeeding. Each breastfeeding mother has different technologic needs. By providing a range of choices and referrals, primary health care providers may facilitate the optimal decision for each lactating mother, which contributes to reaching the goals of the American Academy of Pediatrics for optimal infant feeding, that is, exclusive breastfeeding for the first 6 months of an infant's life, with continued breastfeeding for 1 year or more.

Breast Feeding↗
PubMed1999

Locomotion elicited by MK801 in developing and adult rats: temporal, environmental, and gender effects.

The effects of environmental novelty on locomotion elicited by an N-methyl-D-aspartate (NMDA) receptor antagonist, (+)MK-801 hydrogen maleate [(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine], were investigated. Male and female rats aged 10, 20, 30 or 54-68 days were injected s.c. with MK801 and placed in activity monitors either immediately (no-delay) or after a 60 min delay (delay). In the no-delay condition, MK801 induced an inverse U-shaped dose-response effect on locomotion; peak activation occurred with 0.1 mg/kg and ataxia occurred with higher doses. The introduction of a novel environment 60 min after drug injection shifted the dose-effect function of MK801 to the left; i.e., in rats 20 days of age and older, the activity induced by 0.1 mg/kg MK801 was potentiated in the delay condition. For the 0.5 mg/kg dose, 20-day-olds showed activation in the no-delay condition but ataxia in the delay condition. This dose induced ataxia followed by activation in 30-day-olds and adult males or ataxia in adult females, regardless of delay condition. Age-, gender-, and novelty-dependent variations in MK801-induced locomotion may reflect differences in limbic-motor circuitry.

Age Factors↗
PubMed1999

The locomotor effects of MK801 in the nucleus accumbens of developing and adult rats.

This developmental study was an investigation of locomotion induced by the NMDA receptor antagonist, (+)MK-801 hydrogen maleate [(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine], at doses of 0, 3 or 10 microg injected bilaterally into the nucleus accumbens of rats at 11, 21, 31, or 61-66 days of age. During a 2-h test session, only a few 11-day-old pups responded to either dose of MK801; they displayed short bouts of obstinate progression. In contrast, 21- and 31-day-olds were not affected by 3 microg MK801 but exhibited robust activation after 10 microg MK801. The activation was greatest in 21-day-olds and also occurred after mid-striatal injections in 21- but not 31-day-old rats. Adult rats injected with MK801 were not robustly activated, but they maintained their initial level of activity throughout the test session, instead of habituating to the test monitor, as controls did. Ontological changes in MK801-induced activity are likely to reflect maturation of glutamate transmission in the nucleus accumbens.

Animals↗
PubMed1996

The locomotor effects of a putative dopamine D3 receptor agonist in developing rats.

Dopamine receptors have been categorized into subfamilies D1 and D2, each with separate roles in dopamine-mediated behaviors. Of the D2 subfamily, the dopamine D3 receptor has been cloned, but the behavioral effects of selectively stimulating the D3 receptor are largely unknown. The purpose of this study was to quantify the locomotor responses of developing rats to the putative dopamine D3 receptor agonist, 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT). One of three doses of 7-OH-DPAT (0.01, 0.10, 1.00 mg/kg) or saline was injected subcutaneously into rats at the age of 10,20,30, or 60 days. Five minutes after the injection, rats were placed in automated activity monitors which recorded locomotor behavior at 5 min intervals for 2 h. The high dose of 7-OH-DPAT increased locomotor activity in rats of all ages. The medium and low doses increased activity in 10- and 20-day-old rats but not in 30- or 60-day-old rats. The level of drug-induced activation peaked at 20 days of age. In 30- and 60-day-old rats, but not 10- and 20-day-old rats, a period of locomotor suppression preceded the activation in response to the high dose of 7-OH-DPAT. In rats aged 20 days and older, the middle and low doses decreased locomotion early in the test session, but activation did not ensue. This dose-response pattern across ontogeny closely resembles that induced by quinpirole, an agonist at the dopamine D2 receptor subfamily.

Age Factors↗
PubMed1989

A normative study of step vergence in elementary schoolchildren.

The purpose of this study was to develop normative data for step vergence testing in children age 6-12. Such data are not currently available for this age group. Base-in and base-out step vergence testing with a prism bar was performed on 386 elementary schoolchildren who had all passed a modified clinical technique (MCT) screening. A new polarized target was developed which enabled us to detect suppression, as well as diplopia or blur. The findings suggest significant differences from normative data previously reported for adults. Because the data for 6-year-olds were different from the rest of the group, we suggest that lower norms be used for this age group. This study provides expected findings for step vergence testing outside the phoropter, which can be used clinically for the assessment of disparity vergence ranges in young children.

Child↗
PubMed1988

Normative study of accommodative facility in elementary schoolchildren.

Although accommodative facility testing is used widely in the evaluation of accommodation in children, published normative data are not available for this age group. Current values being used are based upon studies of adult populations. In order to establish norms, 542 elementary schoolchildren were screened. Those that passed a specific set of criteria were included in the accommodative facility assessment. We used a new target and instructional set, which took into consideration the problems associated with subjective testing of young children. The results revealed lower mean accommodative facility values for both monocular and binocular accommodative facility than the values obtained previously from adult populations. These new findings can be used as a clinical guide to evaluate accommodative facility in young children.

Accommodation, Ocular↗
PubMed1986

Isolation and characterization of highly serum-dependent cells released early from collagenase digested calvaria.

A subclass of highly serum-dependent bone cells has been identified among the cells released early from calvaria following digestion in collagenase. Partial purification for these cells has been carried out based on the observation that they require serum for attachment to polystyrene culture flasks. This subclass of bone cells differs from adherent cells and late released osteoblasts, in that they express almost no cAMP response to PTH, require high levels of serum (10%) for initial growth and proliferation, and do not increase DNA synthesis in response to PTH. In common with adherent cells and late released osteoblasts, their proliferation is decreased by 1,25(OH)2D3 at doses above 0.2 ng/ml and they respond to PGE2 with increased DNA synthesis. These similarities suggest an ontogenic relationship with osteoblasts. Based on their differences, however, provisional identification of these cells as relatively undifferentiated mesenchymal cells is suggested.

Animals↗
PubMedDate not supplied

Time limitation for early breastfeeding.

To prevent nipple soreness, mothers who are breastfeeding are counseled to limit the time their infant feeds in the early postpartum period. No evidence supports this method of prevention. To the contrary, nursing and medical literature report that this practice is not effective and that its use should be discontinued. Nursing interventions to prevent nipple problems are presented.

Breast Diseases↗