This study investigated the development of fetal/neonatal rats' ability to distinguish between a novel and familiar taste. Here, we report that neonatal rats alter their orofacial movements (e.g., mouth movements and licks) upon tasting saccharin (SAC) if it was experienced previously. We also sought to determine the origins and duration of this response. Fetuses of embryonic ages E17, E18, or E19 received an oral injection of 10 microL 0.3% SAC while in utero. These animals were then reexposed to SAC on postnatal day 3, (P3) and observations of orofacial motor responses were recorded. Only neonates that first experienced SAC on E19 exhibited a SAC-induced stimulation of mouthing and licking on P3. These data suggested that a taste-recognition memory (TRM) is maintained for up to 5 days (i.e., E19 to P3). However, in this paradigm, the youngest fetuses also have the longest retention interval. Could these data also reflect the limitations of the E17 and E18 fetuses in retaining the TRM? In a second study, we shortened the taste exposure-reexposure interval to 2 days in an attempt to detect the TRM in younger fetuses. As expected, E19 rats exhibited a TRM when tested on E21. However, neither the E17 nor E18 fetuses showed SAC-induced increases in mouthing and licking when tested 2 days after their initial exposure (E19 or E20). Finally, in order to determine whether a TRM could be detected in fetuses as well as neonates (see above), we conducted an additional study wherein E21 fetuses were tested before parturition. Like E21 neonates, E21 rat fetuses that had received SAC on E19 showed a differential response to SAC depending on whether it was novel or familiar. Thus, although E21 fetal orofacial movements were less frequent than those of the E21 neonate, the fetal-testing procedures were not sufficient to obscure the detection of a TRM. In summary, the data indicate that E19 rat fetuses can acquire a TRM and retain it for at least 2-5 days, whereas E17 and E18 fetuses cannot.

Aging↗

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Dissection autoradiography: a screening technique using storage phosphor autoradiography to detect the biodistribution of radiolabelled compounds.

INTRODUCTION: This study reports an alternative, rapid, whole body autoradiography technique which utilises storage-phosphor imaging technology. Conventionally, tissue or whole body sections have been used to examine the distribution of radiolabelled test compounds. However, the information acquired relates only to the sections examined, and the amount of radioactivity within the whole organ cannot be quantified. We have developed a rapid semi-quantitative technique that produces a concise visual representation of the distribution of the isotope throughout the entire animal: dissection autoradiography (DAR). METHODS: By dissecting a mouse which has been administered 14C-labelled methotrexate (MTX) and drying the tissues on a gel dryer, whole organs and aliquots of body fluids can be exposed to a phosphor imaging plate. The data obtained was analysed with the software associated with the phosphor imaging system and, by using 14C standards, the amount of 14C per total organ or tissue was quantified relative to other samples. Another widely used method to detect radiolabelled material in vivo is tissue solubilisation (TS) followed by liquid scintillation counting (LSC). This conventional method was compared with DAR. RESULTS: The new technique described in this communication was found to have a high level of reproducibility (R(2)= 88-95%). Whilst DAR was less sensitive than TS and LSC, trends over time in the biodistribution of 14C-MTX throughout most tissues were consistent between techniques. DISCUSSION: Whilst TS and LSC was a more sensitive technique, it was labour intensive and expensive in terms of consumables and time when compared with DAR. Dissection autoradiography has the potential to be used to screen quickly large numbers of samples in the biodistribution studies of various conjugates, isomers, derivatives or formulations of a parent compound, following a variety of routes of administration.

Animals↗

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Cholinesterase and self-reported pesticide exposure among pregnant women.

Ascertainment of exposure to cholinesterase-inhibiting pesticides in pregnant subjects is complicated by altered enzyme activity that results from metabolic changes associated with pregnancy. Nevertheless, this study found a high correlation (Pearson chi-square = 13.67, p = .008) between classification of pesticide exposure using self-reported interview information and plasma cholinesterase activity for 203 pregnant women for whom three trimester cholinesterase values were available. All plasma cholinesterase activity values were referenced, by trimester, to a larger sample of 1,050 plasma cholinesterase values from 535 pregnant women. Subjects who lived nearest to agricultural land and who reported that they worked with pesticides in agricultural and other occupations tended to have lower plasma cholinesterase activity than those who reported use of household pesticides only.

Adolescent↗

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The response of endothelial cells to high-energy neutron irradiation.

Explore the source record for details and available documents.

Animals↗

PubMedDate not supplied

Half-ring external fixation in the management of tibial plafond fractures.

OBJECTIVE: To investigate the management of tibial plafond fractures with a half-ring external fixator using half pins. DESIGN: Prospective. SETTING: University teaching hospital. PATIENTS: Twenty-four patients with AO Type A or C tibial plafond fractures. OUTCOME MEASURES: Outcome was assessed by using standard criteria of time to union, incidence of infection and malunion, and incidence of pin-tract sepsis. Functional return was assessed by measuring hindfoot function. A scoring system, incorporating clinical and radiological results, was used to rate the results. RESULTS: When using closed or minimally open reduction techniques and interfragmentary screw fixation for the articular component of the fractures, the results of using a half-ring external fixator with half-pins were comparable with those of using small wire fixators. There was a 4.2 percent incidence of infection, and 75 percent of the patients had good or excellent results. CONCLUSIONS: A half-ring external fixator using half-pins produces results that are comparable to those obtained with small wire external fixation. However, the technique is easier and safer.

Adolescent↗

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Nursing education and service collaborate on graduate curriculum development.

Nursing and nursing education exist because of a need by society. Nursing education is translated into reality by those in nursing service. The authors present a systematic process that was used to determine the need in one community for a master's clinical specialization in pediatric critical care and analyze the relationship between nursing educational goals and the needs of nursing service. This method can be adapted and used by others in program development and evaluation.

Adult↗

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Administration of chlorhexidine to persons with mental retardation residing in an institution: patient acceptance and staff compliance.

Chlorhexidine is beneficial in maintaining the oral health of persons diagnosed with mental retardation. Proper daily oral administration, however, depends upon the compliance of caregivers as well as patient acceptance. If caregivers are noncompliant or if patients are overly resistant to daily applications of chlorhexidine, its proven benefits will not be realized. This study evaluated two methods of chlorhexidine administration for patient acceptance and direct-care staff compliance among 44 institutionalized individuals diagnosed with mental retardation.

Adult↗