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PubMed1996

[Investigation of retention time of intravesical instillation therapy with pirarubicin (THP)].

The effective and less side effect retention time of intravesical instillation therapy with Pirarubicin (THP) was investigated for the treatment of urinary bladder tumor. Fifty-seven cases of urinary bladder tumor were treated by intravesical instillation therapy with THP (20 mg/40 ml) a total of 6 times, with the first instillation at the time of surgery and the other 5 at a rate of three times a week thereafter. The retention time was 30 minutes, and it was allowed to last 10 or 60 minutes for comparison in some cases. Tumor and normal tissue were examined in the first instillation, and normal tissue in the sixth instillation. Infiltration to the bladder wall of THP was observed under fluorescence microscopy. Although the amount of tumor uptake was larger than normal tissue in the first instillation, no satisfactory infiltration was obtained. Repeated administration of THP with the retention time of 30 minutes enhanced the uptake and increased the infiltration in many cases, and side effects were scarcely noted. Retention time of 10 minutes was unsatisfactory, while the retention time of 60 minutes was discontinued in the early stage of treatment due to severe irritative bladder symptoms. Therefore, a retention time of 30 minutes is adequate in the case of repeated administration of THP in a short period.

Administration, Intravesical↗
PubMed1977

[Platelet retention and hypothyroidism: an investigation in patients with thyroid carcinoma treated by total thyroidectomy (author's transl)].

Platelet retention was investigated using a standardized technique with a glass pearl column in 18 patients with malignant thyroid disease treated by thyroidectomy before and after high-dose radioiodine treatment (80 or 150 mCi). As compared with the normal controls platelet retention was significantly lower in 13 hypothyroid patients in whom thyroidectomy had been undertaken at least 6 months previously and hormone substitution therapy had been interrupted 3 weeks before the period of investigation. The remaining 5 patients, studied about 18 days following thyroidectomy, were euthyroid and displayed platelet retention values within the lower limits of the normal range except for one patient with markedly reduced values. Thyroid substitution therapy with synthetic preparations induced recovery of platelet retention in both groups examined over a 4 week period, the increase being highly significant in the group of hypothyroid patients. A transient increase in platelet retention was observed 24 hours after a therapeutic dose of radioiodine, and initial values being regained after a further 24-hour period. This phenomenon was found in both, the euthyroid and hypothyroid group, however, it was more pronounced in the latter patients. Our results indicate a dependence of platelet retention on thyroid hormone concentration. The observed transient increase after radioiodine may be due to a radiation effect.

Adolescent↗
PubMedDate not supplied

The National Health Service Corps: rural physician service and retention.

BACKGROUND: The National Health Service Corps (NHSC) scholarship program is the most ambitious program in the United States designed to supply physicians to medically underserved areas. In addition to providing medical service to underserved populations, the NHSC promotes long-term retention of physicians in the areas to which they were initially assigned. This study uses existing secondary data to explore some of the issues involved in retention in rural areas. METHODS: The December 1991 American Medical Association (AMA) Masterfile was used to determine the practice location and specialty of the 2903 NHSC scholarship recipients who graduated from US medical schools from 1975 through 1983 and were initially assigned to nonmetropolitan counties. We used the AMA Masterfile to determine what percentage of the original cohort was still practicing in their initial county of assignment and the relation of original practice specialty and assignment period to long-term retention. RESULTS: Twenty percent of the physicians assigned to rural areas were still located in the county of their initial assignment, and an additional 20 percent were in some other rural location in 1991. Retention was highest for family physicians and lowest for scholarship recipients who had not completed residency training when they were first assigned. Retention rates were also higher for those with longer periods of obligated service. Substantial medical care service was provided to rural underserved communities through obligated and postobligation service. Nearly 20 percent of all students graduating from medical schools between 1975 and 1983 who are currently practicing in rural counties with small urbanized populations were initially NHSC assignees. CONCLUSIONS: Although most NHSC physicians did not remain in their initial rural practice locations, a substantial minority are still rural practitioners; those remaining account for a considerable proportion of all physicians in the most rural US counties. This study suggests that rural retention can be enhanced by selecting more assignees who were committed to and then completed family medicine residencies before assignment.

Career Choice↗
PubMed1997

Retention of glycosyltransferases in the Golgi apparatus.

A number of Golgi glycosyltransferases has been cloned to date. They all are membrane proteins and share the same type II topology, but they do not possess an obvious sequence homology which would suggest a common Golgi retention signal. However, it was shown that the membrane-spanning domain and its flanking regions contain necessary and sufficient information for Golgi retention of these enzymes. Currently, two mutually complementary models have been proposed to explain the mechanism of Golgi retention of glycosyltransferases mediated by their transmembrane domain. The first model postulates the retention through oligomerization, which prevents enzymes from entering the transport vesicles. The second suggests that retention depends on the length of a membrane-spanning domain and thickness of the membrane along the Golgi complex. It has to be pointed out that neither the oligomerization nor the membrane thickness model alone can answer all questions and further work is still needed to elucidate the retention process of Golgi proteins.

Animals↗
PubMed1982

Role of retention in avoiding expulsion of IUDs--measuring devices for basic research.

320 medicated IUDs were removed from 292 women by means of the dynamometer. This instrument indicates the highest retention force (HRF) in newtons (N). Ages of the women ranged from 17-50 years. The IUDs were fitted in nulligravidae (56%), nulliparous with 1 or more abortions (13%), primiparous (18%), and multiparous (13%) women. The IUDs used were the ML Cu 250-standard, 7 Cu 200, T Cu 200-adapted, with a shortened transversal arm of 15-30 mm and T Cu 200 standard. With the low expulsion rate, the ML Cu 250-standard IUD needed 5.8-5.4N and the 7 Cu 200 3.8-2.6N. The adapted T Cu 200 IUD needed 2.6-1.6N, i.e., about 1N more thant the T Cu 200-standard with an HRF of 1.7-1.0N. As the dynamomoeter only indicated the highest retention force, a retentiograph was devised to demonstrate the different retention forces and phases of the various IUDs by characteristic curves. The possible connections between retention and expulsion of IUDs are discussed. The retention forces of the different IUDs compared are congruent with the published expulsion rates. The retentiograph showed new patterns to test IUDs before they demonstrate side effects in vitro.

Age Factors↗
PubMed2002

Intertrial interval manipulations and passive avoidance retention in young Long-Evans hooded rats.

Results of several studies indicate that young rats generally require more training than do adults to reach comparable criterion levels of passive avoidance behavior. In addition, younger rats generally show poorer retention performance than adults. In the present study, preweanling and weanling Long-Evans rats were given passive avoidance training at intertrial intervals (ITI) of 2 min, 1 hr, or 24 hr until a 600-s criterion was obtained. A 2-week retention test also was given to each subject. Results indicate that ITI had little effect on rate of acquisition or retention. Acquisition and retention performance did improve with age, as is typically reported with other strains of rats. The present results support previous acquisition and retention studies indicating that the ability to acquire and retain a passive avoidance task for weanling and preweanling rats increases with age.

Age Factors↗
PubMed1989

Amount of training and retention by infants.

In studies of animals and adult humans, more training typically leads to better retention. The generality of this finding was assessed in two studies with human infants in which amount of training was manipulated in two different ways. In the first study, 3-month-olds were trained for either 1, 2, or 3 sessions, each 9 min long; in the second, they were trained for a single session that was either 6, 9, 12, or 18 min long. Retention of independent groups was measured after delays ranging from 1 to 21 days. In both studies, different amounts of training did not yield group differences on any of the standard measures of acquisition or after a retention interval of 1 day. After intervals of a week or longer, however, more training led to better retention. Across studies, the long-term retention of groups that were trained for the same amount of time differed. We speculate that subjects learn different things in these two training regimens.

Arousal↗
PubMed2004

Sonographic findings in acute urinary retention secondary to retroverted gravid uterus: pathophysiology and preventive measures.

OBJECTIVES: To explore the pathophysiology of acute urinary retention in women with a retroverted gravid uterus and to suggest measures to prevent its recurrence. METHODS: In five women with a retroverted gravid uterus and acute urinary retention necessitating catheterization, the morphology of the genitourinary system was assessed by using transabdominal, transvaginal and introital sonography. RESULTS: In the supine resting position, the cervix was displaced superiorly and anteriorly by the impacted and retroverted uterus so that it compressed the lower bladder, leading to obstruction of the internal urethral orifice. The upper bladder extended superiorly and overlay the uterus. During straining, urethral motion was not limited and there was an average rotational angle of the bladder neck of 32 degrees, ranging from 21 degrees to 44 degrees. Increasing abdominal pressure further compressed the lower bladder. Measures suggested to the women for the prevention of urinary retention included limiting fluid intake before sleep, changing from the supine to the prone position before getting up and avoiding a Valsalva maneuver but performing a Credé maneuver during voiding. In all except one case these measures successfully prevented recurrence. CONCLUSIONS: Acute urinary retention secondary to a retroverted gravid uterus is caused by a displaced cervix compressing the lower bladder and interfering with drainage to the urethra. The urethra itself is not compressed or distorted. Understanding the pathophysiology of the lower urinary tract may allow maneuvers which prevent acute urinary retention.

Acute Disease↗
PubMed1995

The impairment of retention induced by insulin in mice may be mediated by a reduction in central cholinergic activity.

Immediate posttraining intraperitoneal injection of nonconvulsive doses of insulin (2-20 IU/kg) significantly impaired retention of male Swiss mice tested 24 h after training in a one-trial step-through inhibitory avoidance task. The dose-response curve showed a U-shaped form. However, of the doses tested, only 8 IU/kg was effective. Insulin did not affect response latencies in mice not given the footshock on the training trial, indicating that the actions of insulin on retention performance were not due to nonspecific proactive effects on response latencies. The impairing effects of insulin (8 IU/kg) on retention were time-dependent, which suggests that insulin impaired memory storage. The simultaneous administration of glucose (10-1000 mg/kg) antagonized, in a dose-related manner, the actions of insulin (8 IU/kg) on retention, suggesting that the hormone may have produced a hypoglycemic response leading to a decrease in CNS glucose availability with a subsequent memory impairment. Low subeffective doses of atropine (0.5 mg/kg) or mecamylamine (5 mg/kg), but not methylatropine (0.5 mg/kg) or hexamethonium (5 mg/kg), given immediately after training but 10 min before an ineffective dose of insulin (4 IU/kg), interacted with and impaired retention. The central anticholinesterase physostigmine (35 or 70 micrograms/kg), but not its quaternary analog neostigmine (35 or 70 micrograms/kg), prevented the memory impairment induced by insulin (8 IU/kg). Considered together, these findings are consistent with the view that a decrease in the CNS glucose availability impairs the synthesis and/or release of acetylcholine in brain regions critically involved in memory storage.

Acetylcholine↗
PubMed1996

Reversal of beta-amyloid-induced retention deficit after exposure to training and state cues.

We explored amnesia induced by posttraining injection of beta-amyloid protein (beta A4) in four experiments. Previous reports showed that beta A4 impaired retention of learning maintained either by food reward or by shock relief. The experiments in this paper attempted to determine (1) if the amnesia is specific to the 1-40 beta A4 amino-acid sequence; and (2) if the amnesia can be attributed to a consolidation process. Subjects were 190 male Sprague-Dawley rats, 3 to 6 months old. Subjects were given five training trials on a left-right discrimination in a Y-maze with a food reward and injected immediately afterward with beta A4(1-40) or vehicle. One week later they were trained to criterion. Experiment 1 used a control group that was injected with the reverse-sequence peptide (40-1). The performance of the beta A4(40-1) group was unimpaired. Experiments 2 and 3 attempted to reverse the amnestic effects of beta A4 using noncontingent presentation of aspects of the training context during the retention interval. Experimental subjects in Experiment 2 were exposed to the Y-maze in the absence of reinforcers, 24, 22, and 2 h before retention testing. In Experiment 3, subjects were given a 1-min exposure to the reinforcers, outside the Y-maze, 24 h before retention testing. Both manipulations reversed beta A4-induced amnesia. In Experiment 4, beta A4-induced impairments were reversed by reinjecting beta A4 immediately before retention testing. Results indicate that beta A4 injected after partial training does not interfere with a consolidation process.

Amnesia↗
PubMed1996

Memory modulation by post-training glucose or insulin remains evident at long retention intervals.

Immediate posttraining intraperitoneal injection of alpha-D[+]-glucose (30 mg/kg) facilitated, whereas a nonconvulsive dose of insulin (8 IU/kg) impaired, 24-h retention, in male Swiss mice, of a one-trial step-through inhibitory avoidance task. When mice were trained and received immediate post-training glucose or insulin injections and were tested for retention either 1 week or 1 month later, at each retention interval performance was comparable to that found with a 24-h retention interval. Thus, memory modulation by post-training administration of either glucose or insulin remain evident at long retention intervals.

Animals↗
PubMed1996

Effects of posttraining administration of glucose on retention of a habituation response in mice: participation of a central cholinergic mechanism.

Male Swiss mice were allowed to explore a novel environment, provided by an open-field activity chamber, for 10 min. The procedure was repeated twice with a 24-h interval. The difference in the exploratory activity between the first (training) and the second (testing) exposures to the chamber was taken as an index of retention of this habituation task. Posttraining intraperitoneal administration of glucose (10-300 mg/kg) enhanced retention in a dose-related manner, although only the dose of 30 mg/kg of glucose produced significant effects. Thus, the dose-response curve adopted an inverted U-shaped form. Glucose (30 mg/kg) given to untrained mice did not modify their exploratory performance when recorded 24 h later. The effects of glucose on retention were time-dependent, suggesting an action on memory storage. The memory-improving actions of glucose were prevented by the simultaneous administration of both the central acting muscarinic cholinergic antagonist atropine (0.5 mg/kg) and by the central acting nicotinic cholinergic antagonist mecamylamine (5 mg/kg). In contrast, neither methylatropine (0.5 mg/kg), a peripherally acting muscarinic receptor blocker, nor hexamethonium (5 mg/kg), a peripherally acting nicotinic receptor blocker, prevented the effects of glucose on retention. Low subeffective doses of glucose (10 mg/kg) and the central anticholinesterase physostigmine (35 microg/kg), but not neostigmine (35 microg/kg), given together, act synergistically and facilitated retention. We suggest that glucose modulates memory storage of one form of learning elicited by stimuli repeatedly presented without reinforcement, probably through an enhancement of brain acetylcholine synthesis and/or its release.

Animals↗
PubMed1996

The effects of intra-amygdala infusion of the AMPA receptor antagonist CNQX on retention performance following aversive training.

The aim of these experiments was to determine whether impaired retention performance in aversively motivated tasks, induced by blockade of amygdala AMPA receptors, is due to influences on mechanisms underlying memory retrieval or to other influences on performance. Rats received either footshock escape training (1 or 10 trials), or no foot shock, in a two-compartment straight alley and bilateral intra-amygdala infusions of the AMPA receptor antagonist CNQX (0.5 microgram) were subsequently administered prior to inhibitory avoidance retention testing 8 days later. The CNQX impaired, but did not block, inhibitory avoidance retention performance as indicated by the initial latencies to enter the shock compartment. The animals were then retained in the alley until they remained in the starting compartment for 100 consecutive s and entries into the shock compartment were recorded as errors. In both the controls and CNQX-treated groups, increases in amount of original training resulted in fewer errors, indicating memory for the escape training. Furthermore, regardless of the amount of original training (i.e., 0, 1, or 10 trials), CNQX-treated groups made more errors. Other experiments examined intra-amygdala CNQX effects on reactivity to footshock, locomotor activity, and anxiety. CNQX decreased reactivity to footshock, blocked shock-induced decreases in locomotor activity, and had an anxiolytic effect in an elevated plus maze comparable to that induced by midazolam (0.5 microgram). These findings suggest that intra-amygdala infusions of CNQX prior to retention testing affect inhibitory avoidance retention performance following aversive training by altering locomotor activity, reducing sensitivity to footshock, and reducing anxiety. The implications of these findings for hypotheses concerning amygdala function in aversively motivated learning and memory is discussed.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1991

Does alpha sympathetic blockade prevent urinary retention following anorectal surgery?

Urinary retention is the most common complication after anorectal surgery, with rates as high as 52 percent reported. With the trend toward early discharge, avoidance of this complication is particularly important. Perioperative fluid restriction and the use of short-acting anesthetics have been shown to be effective in decreasing postoperative urinary retention rates but are not applicable in all cases. Reflex sympathetic stimulation, possibly as a result of perianal pain, may lead to increased muscular tone of the internal sphincter at the bladder neck. This theory had led to the effective use of alpha-adrenergic blockade in the treatment of established cases of urinary retention after anorectal surgery, herniorrhaphy, and major pelvic surgery. However, the prophylactic role of alpha blockade after anorectal surgery has not been studied. In a double-blind, prospective, randomized study, 51 patients were treated with either prazosin and alpha-adrenergic blocker or placebo prior to and immediately after elective anorectal surgery. Urinary retention rates were similar in the two groups. At this time, prophylactic alpha-adrenergic blockade is not recommended for the prevention of urinary retention after anorectal surgery.

Anal Canal↗
PubMed2002

Long-term retention of motor skill in macaque monkeys and humans.

Remarkable human performance, such as playing the violin, is often based on motor skills that, once acquired, are retained for a long time. To examine how motor skills are retained, we trained monkeys and humans extensively to perform many visuomotor sequences and examined their performance after a long retention period of up to 18 months. For both monkeys and humans, we found strong evidence for long-term retention of motor skills. Each of the monkey subjects initially learned 6-18 sequences of button presses extensively by trial-and-error for up to 18 months. After a long retention period, they were asked to perform the previously learned (OLD) sequences together with completely new (NEW) sequences. The performance for OLD sequences was much better than for NEW sequences in terms of accuracy (assessed by the number of errors to criterion) and speed (assessed by the performance time). However, the retention was interfered with in two conditions, but in selective manners: (1) Learning of other sequences during the retention period interfered with accuracy, but not speed, of performance; (2) Inter-manual transfer was absent for speed, but not accuracy, of performance. The human subjects performed basically the same task as the monkeys. Each subject initially learned one sequence of 20 button presses by trial-and-error during an 8-10 day learning session. After 16 months, they were asked to perform the previously learned sequence (OLD sequence) and additional sequences including RECENT sequences (learned one day before) and NEW sequences. Their performance was considerably better on OLD and RECENT sequences than NEW sequences. Whereas the number of errors (reflecting 'accuracy') was lower for RECENT than for OLD sequences, the performance time (reflecting 'speed') was shorter for OLD than for RECENT sequences. Interestingly, the subjects were unaware that they had experienced OLD sequences. The results suggest that a motor skill is acquired and retained in two different forms, accuracy and speed. This occurs separately but concurrently. This conclusion is consistent with the hypothesis that at least two neural mechanisms operate independently to represent a motor skill.

Adult↗
PubMed2005

Meningitis-retention syndrome. An unrecognized clinical condition.

BACKGROUND: A combination of acute urinary retention and aseptic meningitis has not been well known. This combination can be referred to as meningitis-retention syndrome (MRS), when accompanied by no other abnormalities. OBJECTIVE: To describe the results of a uro-neurological assessment in our patients with MRS. METHODS: In three patients (two men, one woman; age, 34-68 years), we performed urodynamic studies and relevant imaging and neurophysiological tests, in addition to cerebrospinal fluid (CSF) examination. RESULTS: All three patients developed acute urinary retention along with headache, fever and stiff neck. None had obvious neurological abnormalities, other than a slightly brisk reflex in the lower extremities. One had previously experienced generalized erythematous eruptions, but none had pain, hypalgesia or skin eruptions in the sacral dermatomes suggestive of Elsberg syndrome (infectious sacral polyradiculitis; mostly genital herpes). Brain/spinal/lumbar plexus MRI scans and nerve conduction studies were normal. CSF examination showed mild mononuclear pleocytosis, increased protein content, and normal to mildly decreased glucose content in all patients; increased myelin basic protein suggestive of central nervous system demyelination in one; and increased viral titers in none. Urodynamic study revealed, during the voiding phase, an underactive detrusor in all patients and an unrelaxing sphincter in one. These clinical manifestations were ameliorated within 3 weeks. CONCLUSIONS: We reported three cases of MRS, a peculiar syndrome that could be regarded as a mild variant of acute disseminated encephalomyelitis (ADEM). Urinary retention might reflect acute shock phase of this disorder. Although MRS has a benign and self-remitting course, management of the acute urinary retention is necessary.

Adult↗
PubMed1988

Dehydroepiandrosterone and its sulfate enhance memory retention in mice.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), major naturally occurring precursors of both androgenic and estrogenic steroids, were shown in the present study to have convincing memory enhancing effects in mice. Post-training intracerebroventricular (i.c.v.) administration of DHEA in dimethylsulfoxide (2 microliters) prevented the amnesia for footshock active avoidance training (FAAT) caused by the same volume of dimethylsulfoxide alone. DHEAS significantly enhanced retention of FAAT in weakly trained mice whether injected i.c.v. or s.c. immediately post-training or given in the drinking water for a 2-week period. In the latter instance DHEAS was shown to facilitate retention of FAAT without enhancing acquisition. The maximally effective doses were: i.c.v., 162 ng/mouse; s.c., 700 micrograms/mouse; and oral, 1.45 mg/mouse/day. DHEAS administered i.c.v. occluded the amnestic effects of anisomycin (inhibitor of protein synthesis) and scopolamine (muscarinic cholinergic antagonist). There was a time-dependence of the facilitatory effects of post-training i.c.v. administration of DHEAS on retention of FAAT, significant enhancement of retention being observed when it was given either immediately (within 2 min) or at 30 and 60 min after training, but not at 90 or 120 min. DHEAS given i.c.v. also improved retention for step-down passive avoidance. In all instances, dose-dependent inverted U curves were obtained in a manner typical for memory enhancing substances. At a practical level, these experiments open new possibilities for the development of substances that may help in alleviating amnesic disorders in man.

Administration, Oral↗
PubMed1979

Dowel retention with glass-ionomer cement.

The retentive capacity of the Whaledent Parapost system utilizing ASPA cement was compared at two lengths, three diameters, and with respect to the effect of both medication and citric acid pretreatment. The greatest single factor influencing retention was embedment depth into dentin. No significant differences were observed between the retention values for medicated and unmedicated teeth. Finally, no increase in retention was noted over previously reported values for zinc phosphate, carboxylate, and epoxy resin cements. The glass-ionomer cement tested offers no advantage for post retention.

Acid Etching, Dental↗