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Query: UMLS:C0598853 (forgetting)
 3,232 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The study of memory modulation in infant rats has typically focused on reminder/retrieval treatments involving reexposure to components of the internal or external training context. Rarely have studies employed pharmacological treatments to investigate the neurochemical substrates of memory storage in preweanling rats. The present study investigated the effect of 100 mg/kg of glucose, a common memory modulator in adult mammals, on memory for passive-avoidance conditioning in 18-day-old Sprague-Dawley rats. Subjects that were administered an immediate post-training injection of glucose performed significantly better, on a retention test 24 h following training, than those animals that received saline. The glucose group also performed comparably to a control group that was tested 10 min following training. These results are consistent with those of the memory modulation literature in adults and suggest that the rapid rate of forgetting in immature organisms may be the result of a deficiency in a general memory modulatory system.
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PMID:Post-training glucose administration attenuates forgetting of passive-avoidance conditioning in 18-day-old rats. 1037 16

The performance of pigeons in a short-term memory procedure (delayed matching-to-sample) was studied over a range of retention intervals from 0.2 s to 24.0 s. The authors examined the ability of 3 dose levels of glucose (0, 50, and 100 mg/kg) to alleviate memory impairments produced by administration of scopolamine (0.03 mg/kg), by a reduction in the sample-response requirement and by interpolating retroactive interference in the retention interval (houselight illumination). Glucose administration attenuated the deficit produced by scopolamine and by the reduced sample-response requirement, by reversing the decrement in accuracy at 0 delay. Glucose did not, however, reverse the increase in rate of forgetting generated by retroactive interference. The results suggest that the mode of action by which glucose is able to attenuate drug-induced and behavioral impairments in memory may be through an effect on attentional or encoding processes.
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PMID:Glucose attenuation of memory impairments. 1083 92

This work describes oral contraceptives (OCs) in current use and examines their risks. OC pills are composed of synthetic estrogens, usually either ethinyl estradiol or mestranol, and progestins. Either estrogens or progestins can be used alone, but combinations permit smaller doses to be used. Combined pills are available in monophasic, biphasic, or triphasic formulations. Different modalities of administration are also available for progestin-only pills. The "morning after" pill containing high doses of steroids to be taken within 72 hours of unprotected intercourse can contain either estrogen or progestin alone or combined. The mechanisms of action of OCs vary according to the type of pill. Classic combined OCs inhibit ovulation, render the cervical mucus inhospitable to sperm, and cause endometrial atrophy which hinders nidation. Low-dose pills have various effects but in general depend on changes in the cervical mucus for their contraceptive effect. Pregnancy may result from forgetting pills or using them incorrectly, or in the case of low-dose pills may occur even if they are used correctly. Some drugs can lower the concentrations of the OC hormones at the level of the receptors by hindering their intestinal absorption or by increasing the metabolic power of the liver. Considerable individual variability limits the incidence of pill failure due to drug interactions, but OC use should be avoided if rifampicine or certain other drugs are used. Among undesirable effects of OCs on endocrine glands and reproductive function are the adaptation syndrome characterized by symptoms similar to those of early pregnancy and reversible in most but not all women; galactorrhea resulting from diminished levels of "prolactin inhibiting factor"; and virilizing effects such as alopecia, hirsutism, and acne usually occurring during use of high-dose formulations. Pills should be carefully adapted to the hormonal profile of the user to avoid these side effects. OCs very rarely entail longterm infertility. OCs in current use do not appear to be teratogenic but it is advisable to wait 2 months after termination of use before becoming pregnant. Lactation is a contraindication to OC use. Combined OCs frequently cause problems in glucose tolerance of variable significance. Low-dose progestins do not seem to affect lipid metabolism, but low and normal dose combined pills may provoke increases in the levels of cholesterol and triglycerides. OCs are implicated in vascular accidents of various kinds, but low-dose pills are better tolerated. Cardiovascular risks are increased by age, smoking, use of alcohol, and excess fat in the diet. Hepatobiliary complications may occur during pill use. The carcinogenic role of OCx remains controversial, although growth of preexisting breast cancers is accelerated with pill use. The multifactorial etiologies of cardiovascular ailments, atherosclerosis, and cancerous tumors make the role of OCs difficult to assess. OCs can interact with various drugs, heightening the undesirable effects of each. Research on hormonal methods of contraception is currently directed toward achieving a better tolerance and administration of both male and female methods.
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PMID:[Oral contraception: failures and risks]. 1228 May 90

Combined oral contraceptives (OCs) are used by approximately 55 million women throughout the world. Given their effectiveness, easy use, and good tolerance, they will probably continue to be the most used contraceptive method in the developed world for years to come. Research therefore continues with a view to minimizing the rare but serious complications of OCs. Development of new progestins and decreasing of dose levels are 2 goals. The hormonal properties of natural progesterone are well defined. Synthetic progestins have 3 major advantages over natural progesterone: better bioavailability by the oral route, superior progestomimetic activity, and more marked antiestrogenic and antigonadotropic effects. Of the 2 large chemical classes of progestins, those derived from progesterone are primarily used in therapy while those derived from nortestosterone are used in both therapy and contraception. Within these classes, each progestin has a specific pharmacologic profile which determines its uses. The major advantage of the norsteroids for contraception is their strong antiovulatory action, but their varying androgenic properties are responsible for undesirable cutaneous and metabolic side effects. Gestodene, a new progestin, combines a strong antigonadotropic and progestomimetic action with an absence of androgenic and estrogenic effects at contraceptive doses. Tests in rats and mice demonstrate that gestodene inhibits ovulation in 100% of cases at 1/3 the dose of levonorgestrel. The threshold dose for women is the lowest of any of the gonane progestins. Tests of endometrial transformation and affinity to progesterone receptors indicate that gestodene is 3 to 30 times more active than levonorgestrel. Gestodene's strong luteomimetic activity assures reinforcement of contraceptive control by endometrial transformation and permits creation of hormonal balance. Because of its weak androgenic character, gestodene at contraceptive doses causes no modification in lipid or glucose parameters in animals. A new triphasic OC containing gestodene combines 3 successive phases lasting 6, 5, and 10 days with 50, 70, and 100 mcg of gestodene and 30, 40, and 30 mcg of ethinyl estradiol respectively. At these doses the inhibition of ovulation was shown by pelvic sonography, serum levels of estradiol and progesterone, and other tests to be constant. A multicenter study of 27,308 cycles showed a Pearl index of .1 despite forgetting of pills in 669 cycles. The rate of amenorrhea was .3%. Cycle control was excellent. Various studies of the effect on lipid and glucose parameters and on hemostasis demonstrated a high degree of tolerance consistent with the low steroid dose and minimal androgenicity of the progestin.
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PMID:[Thirty years after the appearance of the first oral contraceptive, clinical and biological analysis of a new estrogen-progestin combination, a three phase pill containing gestodene]. 1234 78

Following 2 h of unrestricted access to a black and a white arm of a Y maze, 8-month-old "adult" and 21-month-old "middle-aged" rats were injected intraperitoneally with 0 (vehicle), 50 or 100 mg/kg D-glucose. Twenty-four hours later they were allowed free access to two black arms. When treated with vehicle, there was no evidence of any memory for change as determined by first and total entries of, and time spent in the changed arm. However, the adult "younger" rats showed significant awareness of the changed arm following treatment with the higher dose of glucose. It was concluded that, for adult rats only, treatment with glucose prevented forgetting of their pretreatment experience with the maze arms thereby enabling detection and choice of the changed alternative. It was also suggested that the experimental procedure might have potential as a measure of memory, in particular, one not dependent on deprivation and reinforcement, in the absence of current effects of glucose or other enhancing agents.
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PMID:Prevention of memory loss for a brightness change in adult and middle-aged rats by postacquisition treatment with glucose. 1367 24

Although baseline blood glucose levels in aged Fischer-344 rats are comparable to those of young rats, the rise in blood glucose in response to training-related stress is substantially attenuated. The diminished response may contribute to increased depletion of extracellular brain glucose levels during training in aged rats; the depletion is blocked and memory is enhanced by systemic injections of glucose. The present experiment examined the role of glucose in regulating memory for reward reduction training. Blood glucose levels exhibited a significant rise after reward reduction trials in young adult but not 2-year-old rats. Although young and aged rats exhibited comparable learning during the day of reward reduction training, aged rats exhibited more rapid forgetting of the learning response. Post-training glucose injections (200 mg/kg, i.p.) facilitated memory formation and slowed the rate of forgetting in young and old rats, consistent with the view that deficiencies in circulating glucose responses to training may contribute to the rapid forgetting evident in aged Fischer-344 rats.
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PMID:Glucose regulation of memory for reward reduction in young and aged rats. 1558 45

In 181 urban African Americans with Type 2 diabetes, medication adherence was assessed using a measure designed specifically for an urban, impoverished sociodemographic population. Hemoglobin A-sub(1c), blood pressure and cholesterol levels, medication-related beliefs, and depression were assessed. Seventy-four percent of the sample reported adherence to diabetes medication. Adherence, adjusted for age, was associated with lower hemoglobin A-sub(1c). The specific behaviors associated with poorer diabetes control were forgetting to take medications and running out of medications. Knowledge of blood glucose goals differed for adherers and nonadherers. Blood pressure and cholesterol medication adherence rates were not associated with actual levels of blood pressure or lipids, respectively. These data suggest that specific medication-taking behaviors are important to diabetes control and constitute logical targets for interventions. ((c) 2005 APA, all rights reserved).
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PMID:Medication adherence and diabetes control in urban African Americans with type 2 diabetes. 1604 70

Following confinement to one chamber of a two-chamber exploration box (acquisition trial), male and female rats were intraperitoneally injected with saline, glucose (50, 100 mg/kg) or tacrine (1, 3 mg/kg). Twenty-four hours later they were given free access to this chamber and an identical novel one (retention trial). Tendencies to occupy the novel chamber (novelty-related location preferences) were increased by both doses of glucose for females and by the higher dose for males. While neither dose of tacrine affected this response for females, increased preferences occurred for males following the higher dose. However, when the higher doses of both agents were administered 2 h after acquisition, there were no significant effects for either sex. In view of the rats' lack of significant preferences for the novel chamber when treated with saline both immediately and 2 h after acquisition, the results were interpreted as sex-dependent attenuation of forgetting by post-acquisition treatment with both agents.
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PMID:Memory-dependent novelty-related location preferences: sex-related attenuation of forgetting by D-glucose and tacrine. 1616 30

As a glucose containing drink has been reported to improve memory, and missing breakfast has been reported to adversely influence memory late in the morning, meals designed to differ in their ability to release glucose into the blood stream were contrasted. Using a factorial design, breakfasts containing 15, 30 or 50 g of carbohydrate and 1.5, 6 or 13 g of fibre were compared. The glucose tolerance of participants proved to be an important factor. Those with better tolerance reported better mood. Those eating breakfasts containing greater amounts of carbohydrate reported feeling tired rather than energetic. The amount of carbohydrate did not negatively affect memory in those with better glucose tolerance, however, the consumption of more carbohydrate resulted in more forgetting in those with poorer glucose tolerance. The effect with reactions times differed from memory in that a greater intake of carbohydrate resulted in faster responses later in the morning.
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PMID:The effect of the interaction between glucose tolerance and breakfasts varying in carbohydrate and fibre on mood and cognition. 1717 39

In this study, healthy adolescents consumed either (i) a low glycaemic index breakfast cereal meal or (ii) a high glycaemic index breakfast cereal meal, before completing a test of verbal episodic memory in which the memory materials were encoded under conditions of divided attention. Analysis of remembering/forgetting indices revealed that the high glycaemic index breakfast group remembered significantly more items relative to the low glycaemic index breakfast group after a long delay. The superior performance observed in the high glycaemic index group, relative to the low glycaemic index group, may be due to the additional glucose availability provided by the high glycaemic index meal at the time of memory encoding. This increased glucose availability may be necessary for effective encoding under dual task conditions.
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PMID:The impact of a high versus a low glycaemic index breakfast cereal meal on verbal episodic memory in healthy adolescents. 1878 82


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