The medial prefrontal cortex during flexible decisions: Evidence for its role in distinct working memory processes

During decisions that involve working memory, task-related information must be encoded, maintained across delays, and retrieved. Few studies have attempted to causally disambiguate how different brain structures contribute to each of these components of working memory. In the present study, we used transient optogenetic disruptions of rat medial prefrontal cortex (mPFC) during a serial spatial reversal learning (SSRL) task to test its role in these specific working memory processes. By analyzing numerous performance metrics, we found: (1) mPFC disruption impaired performance during only the choice epoch of initial discrimination learning of the SSRL task; (2) mPFC disruption impaired performance in dissociable ways across all task epochs (delay, choice, return) during flexible decision-making; (3) mPFC disruption resulted in a reduction of the typical vicarious-trial-and-error rate modulation that was related to changes in task demands. Taken together, these findings suggest that the mPFC plays an outsized role in working memory retrieval, becomes involved in encoding and maintenance when recent memories conflict with task demands, and enables animals to flexibly utilize working memory to update behavior as environments change.

Anti-inflammatory, procollagen, and wound repair properties of topical insulin gel

Diabetes mellitus is associated with impaired wound healing. The topical use of insulin is a promising therapy because it may favor all phases of the wound healing process. This study aimed to investigate the therapeutic outcomes of insulin gel in wounds of hyperglycemic mice. After diabetes induction, a 1-cm2 full-thickness wound was created on each animal's dorsum. The lesions were treated daily for 14 days with insulin gel (insulin group) or vehicle gel without insulin (vehicle group). Tissue samples were extracted on days 4, 7, 10, and 14 after the creation of the lesion. The samples were analyzed with hematoxylin/eosin and Sirius red staining, immunohistochemistry, Bio-Plex immunoassays, and western blotting. Insulin gel favored re-epithelialization at day 10 and increased the organization and deposition of collagen. Additionally, it modulated the expression of cytokines (interleukin (IL)-4 and IL-10) and increased the expression of arginase I, VEGF receptor 1, and VEGF on day 10. Activation of the insulin signaling pathway occurred via IRβ, IRS1, and IKK on day 10 and activation of Akt and IRS1 on day 14. These results suggested that insulin gel improved wound healing in hyperglycemic mice by modulating the expression of inflammatory factors, growth factors, and proteins of the insulin signaling pathway.

Adrenergic regulation of the vasculature impairs leukocyte interstitial migration and suppresses immune responses

The sympathetic nervous system (SNS) controls various physiological functions via the neurotransmitter noradrenaline. Activation of the SNS in response to psychological or physical stress is frequently associated with weakened immunity. Here, we investigated how adrenoceptor signaling influences leukocyte behavior. Intravital two-photon imaging after injection of noradrenaline revealed transient inhibition of CD8⁺ and CD4⁺ T cell locomotion in tissues. Expression of β-adrenergic receptor in hematopoietic cells was not required for NA-mediated inhibition of motility. Rather, chemogenetic activation of the SNS or treatment with adrenergic receptor agonists induced vasoconstriction and decreased local blood flow, resulting in abrupt hypoxia that triggered rapid calcium signaling in leukocytes and halted cell motility. Oxygen supplementation reversed these effects. Treatment with adrenergic receptor agonists impaired T cell responses induced in response to viral and parasitic infections, as well as anti-tumor responses. Thus, stimulation of the SNS impairs leukocyte mobility, providing a mechanistic understanding of the link between adrenergic receptors and compromised immunity.

Quorum-sensing genes in Pseudomonas aeruginosa biofilms: their role and expression patterns

Acylated homoserine lactone molecules are used by a number of gram-negative bacteria to regulate cell density-dependent gene expression by a mechanism known as quorum sensing (QS). In Pseudomonas aeruginosa, QS or cell-to-cell signaling controls expression of a number of virulence factors, as well as biofilm differentiation. In this study, we investigated the role played by the las and rhl QS systems during the early stages of static biofilm formation when cells are adhering to a surface and forming microcolonies. These studies revealed a marked difference in biofilm formation between the PAO1 parent and the QS mutants when glucose, but not citrate, was used as the sole carbon source. To further elucidate the contribution of lasI and rhlI to biofilm maturation, we utilized fusions to unstable green fluorescent protein in concert with confocal microscopy to perform real-time temporal and spatial studies of these genes in a flowing environment. During the course of 8-day biofilm development, lasI expression was found to progressively decrease over time. Conversely, rhlI expression remained steady throughout biofilm development but occurred in a lower percentage of cells. Spatial analysis revealed that lasI and rhlI were maximally expressed in cells located at the substratum and that expression decreased with increasing biofilm height. Because QS was shown previously to be involved in biofilm differentiation, these findings have important implications for the design of biofilm prevention and eradication strategies.

Left ventricular morphology in junior and master resistance trained athletes

PURPOSE

The objective of this cross-sectional investigation was to assess the effects of short (< 5 yr) versus long-term (> or = 18 yr) resistance training (RT) on left ventricular (LV) dimensions and mass.

METHODS

The subjects for this study were 20 elite male powerlifters (8 junior athletes [JA], mean +/- SD, age: 21.1 +/- 1.2 yr and 12 master athletes [MA], age: 46.0 +/- 5.5 yr) and 19 age-matched male controls (8 young controls [YC], age: 21.8 +/- 2.8 yr and 11 middle-aged controls [MAC], age: 46.8 +/- 4.4 yr). Two-dimensionally guided transthoracic M-mode echocardiograms were performed at rest to quantify LV systolic and diastolic cavity dimension (LVIDs and LVIDd, respectively), ventricular septal wall thickness (VST), posterior wall thickness (PWT), LV mass (LVM), and LV systolic function as measured as fractional shortening (FS).

RESULTS

Short- or long-term RT was not associated with a significant alteration in LVIDd (JA: 53.2 +/- 4.5 mm, YC: 52.1 +/- 3.7 mm, MA: 53.0 +/- 5.1 mm, MAC: 51.8 +/- 4.4 mm), LVIDs (JA: 33.5 +/- 4.8 mm, YC: 32.9 +/- 3.4 mm, MA: 33.0 +/- 4.4 mm, MAC: 31.4 +/- 3.7 mm), VST (JA: 9.4 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.4 +/- 1.6 mm, MAC: 9.7 +/- 0.9 mm), PWT (JA: 9.2 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.0 +/- 1.1 mm, MAC: 9.5 +/- 1.0 mm), LVM (JA: 184.6 +/- 36.1 g, YC: 179.0 +/- 26.5 g, MA, 183.3 +/- 58.1 g, MAC: 184.1 +/- 38.1 g), or FS (JA: 0.37 +/- 0.1%, YC: 0.37 +/- 0.05%, MA: 0.38 +/- 0.1%, MAC: 0.40 +/- 0.04%).

CONCLUSIONS

These findings suggest that short or long-term RT as performed by elite junior and master powerlifters does not alter LV morphology or systolic function.

Giant congenital aortic aneurysm with cleft sternum, supraumbilical raphé, and hemangiomatosis: report and review

We report on a child with giant congenital aortic aneurysm, sternal defect, hemangiomas of face, supraumbilical raphé, and review the only two other cases reported to date. Congenital aortic aneurysm is an ominous malformation that has to be systematically searched in children with the sternal malformation/vascular dysplasia complex.

Left ventricular morphology in elite female resistance-trained athletes

Long-term resistance training as performed by elite female resistance-trained athletes appears to be an insufficient stimulus to alter left ventricular cavity size, wall thickness, or estimated mass.

Ritualistic female genital mutilation: current status and future outlook

Ritualistic sexual mutilation of females dates back to the fifth century B.C. This traditional practice is a social as well as a health issue that affects the physical and mental well being of the women who undergo it. Although practiced mostly in African countries north of the equator and the Middle-East, concern has recently been expressed that female genital mutilation is also being practiced in the U.S., Europe, and other western countries by immigrants from these countries. This review describes the various types of female genital mutilation and presents the historical and cultural background of the tradition, outlines the medical, psychological and sexual problems, and discusses the current status and future outlook for this tradition, emphasizing social, medical, and legislative aspects.

Central precocious puberty and chronic renal failure: a reversible condition post renal transplantation

A 3 year-old boy with chronic renal failure associated with prune belly syndrome who developed central precocious puberty is described. He had been maintained on cyclic peritoneal dialysis from age 13 months with creatinine levels of 400-600 mumol/l. Increased linear growth rate probably began at 18 months, and by 38 months of age he had testicular enlargement and pubic hair consistent with Tanner stage 2. Elevated levels of serum testosterone (3.6 nmol/l; normal < 0.7 nmol/l) and luteinizing hormone (LH) (2.8 IU/l; normal < 1.0 IU/l) were demonstrated with a pubertal response to luteinizing hormone-releasing hormone (LHRH) stimulation (peak LH 43.5 IU/l). Other endocrine tests demonstrated hyperprolactinemia (170 micrograms/l; normal 3.4-22 micrograms/l), but normal pituitary-thyroid and pituitary-adrenal functions and normal cranial MR imaging. Despite LHRH-agonist therapy with leuprolide over the next 8 months, he showed an incomplete response with only partial inhibition of basal LH and testosterone levels, and continued significant increments in height standard deviation scores (Ht-SDS) and bone age estimates. However, the sexual precocity appeared fully reversible following a successful living-related renal transplant at age 50 months. Despite discontinuation of leuprolide treatment post-operatively, there was a full reversal of his serum LH and testosterone to a prepubertal profile as well as normalization of the serum prolactin levels. Whereas most boys with chronic renal failure show delayed pubertal development and suppressed linear growth, our patient presents a unique phenomenon of reversible central precocious puberty. The effects of leuprolide therapy in the presence of a uremic milieu and the outcome of successful renal transplantation on sexual precocity are described.

Presynaptic alpha2-adrenoceptors inhibit excitatory synaptic transmission in rat brain stem

The synaptic connection between the commissural portion of the nucleus tractus solitarius (ComNTS) and the dorsal motor nucleus of the vagus (DMV) was studied in rat brain stem slices, using the patch-clamp technique. The excitatory postsynaptic currents (EPSC) evoked by stimulation of the ComNTS were blocked by kynurenic acid (1 mM) and, in Mg2+-free solution, were sensitive to both the N-methyl-D-aspartic acid (NMDA) receptor blocker 3-[(RS)-2-carboxypiperazine-4-yl] -propyl-1-phosphonic acid (20 microM) and the non-NMDA receptor blocker 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (5 microM). Norepinephrine (NE, 1-100 microM) inhibited the EPSC, and the inhibition was attenuated by the alpha2-adrenoceptor antagonists idazoxan (1 microM) and yohimbine (10 microM) but not by the beta-adrenoceptor antagonist nadolol (50 microM). The NE-releasing agent tyramine (100 microM) reduced the EPSC, and the inhibition was attenuated by 1 microM idazoxan. NE (30 microM) did not affect the membrane input resistance but reduced the paired-pulse depression, demonstrating that NE acts on presynaptic alpha2-adrenoceptors. The results indicate the existence of a glutamatergic pathway from the ComNTS to the DMV neurons modulated by presynaptic NE receptors. This pathway might be a component of the vagovagal reflex regulating gastrointestinal function.

A kindred with Griscelli disease: spectrum of neurological involvement

We report four members of a highly consanguineous family with silver-grey pigmentation of hair, two of whom had skin histology compatible with Griscelli disease. Unlike previously reported patients, they did not suffer from recurrent infections. In addition, there was a spectrum of neurological involvement varying from mild cognitive delay with a convulsive disorder in one patient, to a fatal degenerative course in three others. One patient developed a prolonged febrile illness with histological evidence of florid lymphoid hyperplasia.

Differential effects of speech prostheses in glossectomized patients

Five patients representing different categories of glossal resection were fitted with prostheses specifically designed to improve speech. Speech recordings made for subjects with and without their prostheses were subjected to a variety of analyses. Prosthetic influence on listeners' judgments of severity level/intelligibility, number of consonants in error, and on the acoustic measure F2 range of vowels was evaluated. Findings indicated that all subjects demonstrated improvement on the speech measures. However, the extent of improvement on each measure varied across speakers and resection categories. Implications of the findings for prosthetic speech rehabilitation in this population are discussed.

The Niikawa-Kuroki (Kabuki make-up) syndrome in a Moslem Arab child

The Niikawa-Kuroki "Kabuki Make-Up" syndrome is a rare sporadic malformation syndrome, characterised by severe psychomotor and growth retardation, peculiar facies, including long palpabral fissures and large malformed ears and skeletal abnormalities. We report a 2-year-old Moslem Arab boy with 28 of the 32 originally described features of this syndrome and in addition with hyperelastic joints, hypospadias and scaphocephaly which were not previously described in association with the Kabuki make-up syndrome. This is the fifth reported case of this syndrome in a non-Japanese patient, and the second reported case in a patient of Arab descent.

Comparative cardiorespiratory effects produced by taurine and glycine applied to the ventral surface of the medulla

The purpose of our study was to determine whether taurine, like other naturally occurring central nervous system amino acid neurotransmitters (e.g., gamma-aminobutyric acid and glycine), act at the ventral surface of the medulla to influence cardiorespiratory activity. This was accomplished by monitoring cardiorespiratory activity. This was accomplished by monitoring cardiorespiratory activity in chloralose-anesthetized cats and then applying several doses of taurine locally to the ventral medullary surface chemosensitive areas. We found that 2 and 4 mumol of taurine applied to the intermediate area of the ventral surface produced cardiorespiratory depression, whereas taurine, in a similar dose range, produced only respiratory depression when applied to the rostral area. In contrast, taurine applied to the caudal area had no cardiorespiratory effects. Similar experiments with glycine revealed that this inhibitory amino acid elicited a similar pattern of cardiorespiratory depression as taurine. Furthermore, strychnine, an antagonist of glycine, counteracted the cardiorespiratory depressant effects of both taurine and glycine effectively. Pretreatment with strychnine prevented most of the cardiorespiratory depressant effects of taurine and glycine. 6-Aminomethyl-3-methyl-4H-1, 2,4-benzothiadiazine-1,1-dixoide, a putative antagonist of taurine, had antagonistic effects similar to those of strychnine in both treatment and pretreatment studies. 6-Aminomethyl-3-methyl-4H-1,2,4-benzothiadiazine-1,1-dioxide, per se, increased tidal volume when applied to the intermediate area; strychnine had no effect. These results indicate that taurine acts at the chemosensitive areas on the ventral surface of the medulla to produce cardiorespiratory depression, and these effects are due to an interaction of taurine with receptors similar to, but probably not identical with, glycine receptors.

Effects of a prosthetic tongue on vowel intelligibility and food management in a patient with total glossectomy

Effects of a prosthetic tongue on vowel intelligibility and food management in a patient who underwent total glossectomy are discussed. Results of the vowel intelligibility study indicate improvement from 48% to 64% on the Vowel Rhyme Test with use of the prosthesis. Analyses of listener confusions suggest that the most significant effects of the prosthesis were reductions in height and antero-posterior confusions, and a proportionately larger number of same category errors. Results further reveal that front vowels appear better preserved than back and central vowels, in both prosthesis and nonprosthesis conditions. Effects of the prosthesis on food management are discussed and consideration is given to future prosthesis design and fabrication.