Absence Of Retention Research Articles

Effects of pine bark amendment on the transport of sulfonamide antibiotics in soils

In the present work, laboratory column experiments were carried out to study the effect of pine bark amendment (at doses of 0, 12, 48 and 96 Mg ha−1) on the transport of three sulfonamide antibiotics (sulfadiazine –SDZ-, sulfamethazine –SMT-, and sulfachloropyridazine –SCP-) through two crop soils. All three sulfonamides showed high mobility in the unamend soils, with absence of retention in most cases. However, some differences were detected regarding the degree of interactions between sulfonamides and soils, being higher for soil 1, which was attributed to its higher organic carbon content. For both soils, interactions with the antibiotics studied followed the sequence SDZ < SMT < SCP, indicating an increase as a function of the hydrophobicity of sulfonamides. Pine bark amendment significantly increased the retention of the three sulfonamides in both soils. Specifically, in the case of soil 1, the incorporation of the highest dose of pine bark (96 Mg ha−1) caused that retention increased from 0% to 70.3% for SDZ, from 2.7% to 71.3% for SMT, and from 0% to 85.4% for SCP. This effect of pine bark is mainly attributed to its high organic carbon content (48.6%), including substances with potential to interact and retain antibiotics, as well as to its acidic pH (4.5). Therefore, pine bark amendment would be an effective alternative to reduce the transport of sulfonamides in soils and, thus, decrease risks of passing to other environmental compartments, as well as harmful effects on the environment and public health.

A single-institution experience of complete primary repair of bladder exstrophy in girls: risk factors for urinary retention

Historically after complete primary repair of exstrophy (CPRE) in girls, it had been more likely to observe urinary incontinence than retention. Following recent technical modifications of elongating the urethra and narrowing the bladder neck, the authors have observed a high rate of urinary retention in girls after CPRE. The aim was to identify factors that may be responsible for this observation by reviewing historical and current outcomes. The authors hypothesized that differences in anatomic dimensions at the time of CPRE may contribute to urinary retention. A retrospective review of girls who underwent CPRE from December 1998 through September 2016 from a single institution was performed. Patients were deemed in retention if their clinical course was consistent with such, required a procedure to relieve urinary retention, and/or required clean intermittent catheterization. Nineteen girls underwent CPRE during this period. In 2012, a change to delaying CPRE to approximately 2 months of age was made, and this led the authors to divide their experience into CPRE performed as a newborn (<72h of age, 8 patients) versus delayed (>72h, 11 patients) subgroups. There were no girls with retention in the newborn group and three (38%) girls with retention in the delayed group. In the delayed group, girls had a longer urethral plate and narrower bladder neck compared with the newborn group. Long-term outcomes greater than 9 years are available for six girls in the newborn group and two (33%) required bladder neck procedures for incontinence. None in the delayed group have required incontinence procedures; however, follow-up is limited at 25 months. The absence of retention in the newborn group is concerning for the delayed group incurring a higher risk of retention after CPRE. This may be secondary to excessive compression of the urethra at the time of pubic symphysis approximation potentially leading to urethral ischemia. Different from the newborn CPRE girls, additional technical revision of CPRE, namely, elongation of the urethra and the dissection it involvesand narrowing of the bladder neck, may increase the risk for retention. The multiple factors that were identified as potential contributors to post-CPRE urinary retention should result in a cautious reevaluation of female bladder exstrophy management at the time of CPRE. The authors now create a gradual tapered transition at the bladder neckand, similar to their previous experience, a more generous (wider) bladder neckand a shorter length for urethral plate.

Cooperative learning, student characteristics, and persistence: an experimental study in an engineering physics course

ABSTRACT The dropout rate of university engineering studies is correlated with the absence of retention of freshman in the basic subjects. The aim of this work is to determine the effect of cooperative learning and the characteristics of students on learning, persistence, and academic performance. We have performed a study of learning, persistence and academic performance in an engineering physics course, comparing two groups with different teaching, one traditional and the other through cooperative learning. In addition, we have analysed the influence of the characteristics of the students on the results and the perceptions of the students regarding the teaching. The students of the cooperative learning group had a normalised average gain in the Force Concept Inventory that was 72.7% higher, a significantly higher persistence, and a final grade similar to that of the group receiving traditional teaching. The previous education and the size of the community of origin of the students had a significant effect on the persistence of the students. The perceptions of the subject and lecturer were similar in both groups.

Residents’ journal review

Residents’ journal review

Short-term postorthodontic changes in the absence of retention

To evaluate short-term postorthodontic tooth movement without retention. Thirty consenting patients participated in the study. At the end of active treatment (T(1)), final archwires were removed while leaving the fixed appliances on, and alginate impressions were taken. Four weeks later (T(2)) a second set of impressions was taken. A clinical examination performed at T(2) determined if the fixed appliances could be removed or if additional treatment was required. Based on the examination, patients were divided into two groups. Patients in group I (n = 13) had their fixed appliances removed, while those in group II (n = 17) required additional treatment. The American Board of Orthodontics' Objective Grading System scores and the following six variables were measured on plaster casts at T(1) and T(2): maxillary and mandibular crowding or spacing, overbite, overjet, and mandibular intercanine and intermolar widths. Data were analyzed to detect potential changes from T(1) to T(2) and to evaluate differences between the groups. Mandibular crowding, overjet, and interproximal contacts worsened for the entire sample, while marginal ridges, occlusal contacts, and total American Board of Orthodontics scores improved. No statistically significant changes were found within group I from T(1) to T(2). Mandibular crowding, overbite, overjet, alignment/rotations, and interproximal contacts worsened within group II from T(1) to T(2), while marginal ridges and occlusal contacts improved. Significant differences were noted between the groups in terms of alignment/rotations, interproximal contacts, and mandibular intercanine width. Short-term postorthodontic tooth movement without retainers demonstrated improvement in specific characteristics of the occlusion but negatively affected alignment and interproximal contacts in the sample.

Treatment and posttreatment effects of a facial mask combined with a bite-block appliance in Class III malocclusion

In this cephalometric investigation, we analyzed the treatment and posttreatment effects of an orthopedic protocol for Class III malocclusion consisting of a facial mask combined with a removable bite-block appliance. The treated sample consisted of 22 Class III patients treated with the facial mask and bite-block protocol before the pubertal growth spurt (mean age, 8.9 +/- 1.5 years). Treated subjects were evaluated after facial mask and bite-block therapy and at a posttreatment observation in absence of retention. The treated group was compared with a matched control group of 12 untreated Class III subjects. All treated and control subjects were postpubertal at the final observation. Significant differences between the treated and control groups were assessed with the Mann-Whitney U test (P <0.05). Both angular and linear sagittal measurements of the maxilla showed significant improvements during active treatment. Significant improvements of SNA angle, ANB angle, overjet, and molar relationship remained stable during the posttreatment period. No significant effect was found in the mandibular skeletal measures. No significant protraction of the maxillary incisors or retraction of the mandibular incisors was observed. A bite-block appliance in the mandibular arch with a facial mask enabled effective control of mandibular rotation with progressive closure of the gonial angle. This added to the favorable maxillary outcomes of the treatment protocol.

Systemic harmaline blocks associative and motor learning by the actions of the inferior olive.

Is there a role for the inferior olive in learning? Novel paradigms of conditioning involving tongue protrusion were developed using the rat to test whether: (a) the indole alkaloid harmaline blocks associative learning via actions within the inferior olive, and (b) the inferior olive is required for associative and motor learning. Harmaline blocked associative learning as measured by the absence of conditioned responses to a tone over six daily sessions of conditioning and the absence of retention without harmaline. Harmaline's effect on associative learning was completely blocked by prior removal of the inferior olive with 3-acetylpyridine. Rats whose inferior olives were chronically lesioned showed normal associative learning, normal associative memory, and could learn to modify tongue protrusion via a motor learning paradigm involving response shaping. Removal of the inferior olive degraded the performance of the licking motor system by increasing the latency of conditioned tongue protrusions and by increasing the temporal variability of rhythmic licking elicited by intraoral water. The experiments raise doubt as to whether the inferior olive encodes memory in the cerebellum but demonstrate that the inferior olive is essential for the temporal precision of movement. The results indicate that harmaline's antilearning action is produced by its ability to exaggerate the normal propensity of olivary neurons to fire rhythmically, a process that must be constrained under physiological conditions for normal learning to occur. It is concluded that there may be an important role for the rhythmic activity of inferior olivary neurons in the temporal processes that underlie both motor control and learning.

The Safety and Efficacy of Intrathecal Diamorphine

One hundred and seventy-eight patients undergoing total hip replacement and 67 patients undergoing spinal surgery were given diamorphine intrathecally in varying doses. Doses in mg/kg were plotted against duration of analgesia and the absence of retention and emetic symptoms in each type of surgery. Analysis showed that these were not dose dependent within the therapeutic range of 0.005–0.015 mg/kg.

Pharmacokinetics of the Anti-Inflammatory Tiaprofenic Acid in Humans, Mice, Rats, Rabbits, and Dogs

The pharmacokinetics of tiaprofenic acid were studied in rats, dogs, mice, and rabbits using the 14C-labeled compound and in humans using the radioinert compound. Its absorption was partially gastric but mainly intestinal and was total in all species. Its apparent volume of distribution was small; it was bound markedly to albumin, and its plasma clearance was high in all species. Absence of retention was confirmed in rats by the very low tissue radioactivity levels 24 hr after oral dosing. In humans, identical maximum plasma concentrations and elimination rates were recorded after the first and 40th dose during a 2-week treatment with 200 mg three times daily. During this period, constant residual levels were recorded before the first dose of the day. These results indicate that, for a dose in the therapeutic range, a steady state was reached as early as the end of the 1st day of treatment and that tiaprofenic acid did not inhibit or induce its own biotransformation. Urinary excretion accounted for one-half of the dose in rats and from 0.6 to 0.9 in humans, dogs, mice, and rabbits. Two metabolites were formed, one resulting from the reduction of the ketone group to an alcohol and the other from oxidation generating a phenol in the benzene ring in the paro-position to the ketone group. These two metabolites were common to all species, but the latter was present in minute amounts only in dogs. Tiaprofenic acid was conjugated as an amide in dogs and as an acylglu- curonide in the other species. In rats, phenobarbital induced the oxidative, but not the reductive, pathway.

Interaction of amino acids, N-acetyl amino acid esters, thymine and adenine with sephadex LH-20 gel

N-Acetyl aromatic amino acid esters, tryptophan, adenine and thymine show strong retention in Sephadex LH-20 gel in an aqueous phase. The decreased retention in 6 M urea, the absence of retention in absolute methanol and the increased retention at higher temperatures in the aqueous phase indicate that hydrophobic interaction is responsible for the observed retention of the amino acids and their esters in the gel. Adenine was found to be retained by polar interaction in the gel. The increased retention of the solutes in the presence of different electrolytes suggests that the lyotropic effect is more important than the ionic strength effect. The relevance of the results obtained with amino acids and esters to the conformational aspects of proteins in aqueous solution is discussed.

Amnesic effects of cycloheximide on two strains of mice with different memory characteristics

The amnesic effects of the protein synthesis inhibitor cycloheximide were studied in two strains of mice ( C57BL 6J ; DBA 2J ) which have opposite temporal gradients of retention for single trial passive avoidance learning. Mice were given a single trial in a passive avoidance apparatus 30 min after a saline or a cycloheximide injection and tested for retention at seven intervals from 1 min to 72 hr following. Saline-injected C57BL 6J mice showed poor initial retention followed by progressive improvement which was sustained for 72 hr. In contrast, saline-injected DBA 2J mice showed good retention shortly after training followed by absence of retention 6 hr after training. A 3-mg dose of cycloheximide produced significant amnesia in both strains but the memory impairment was greater in the C57BL 6J strain when tested at 5 min. Increased early amnesia occurred when DBA 2J mice were given 5 mg of cycloheximide even though this dose did not significantly increase degree of protein synthesis inhibition. These results indicate that cyclohexamide can disrupt short-term as well as long-term memory and, in addition, raise the question whether the amnesic effect is due exclusively to inhibition of protein synthesis.