The representation of pleasant touch in the brain and its relationship with taste and olfactory areas

Although there has been much investigation of brain pathways involved in pain, little is known about the brain mechanisms involved in processing somatosensory stimuli which feel pleasant. Employing fMRI it was shown that pleasant touch to the hand with velvet produced stronger activation of the orbitofrontal cortex than affectively neutral touch of the hand with wood. In contrast, the affectively neutral but more intense touch produced more activation of the primary somatosensory cortex than the pleasant stimulus. This indicates that part of the orbitofrontal cortex is concerned with representing the positively affective aspects of somatosensory stimuli, and in further experiments it was shown that this orbitofrontal area is different from that activated by taste and smell. The finding that three different primary or unlearned types of reinforcer (touch, taste, and smell) are represented in the orbitofrontal cortex helps to provide a firm foundation for understanding the neural basis of emotions, which can be understood in terms of states elicited by stimuli which are rewarding or punishing.

Women with obstetric fistula in Ethiopia: a 6-month follow up after surgical treatment

OBJECTIVE

To quantify surgical and quality of life outcomes 6 months after obstetric fistula repair.

DESIGN

A prospective study. Women were examined and questioned at discharge and at follow-up appointment.

SETTING

The Barhirdar Hamlin Fistula Centre, a dedicated unit treating women with obstetric fistula in northern Ethiopia.

POPULATION

All women admitted to the Barhirdar Hamlin Fistula Centre suffering from vesicovaginal (WF) and rectovaginal fistulae (RVF).

METHODS

All women were asked to return for a follow-up appointment 6 months after surgical treatment. A standardised questionnaire and examination were used and information entered into a database.

MAIN OUTCOMES MEASURES

Urinary and anal continence status; extent of return to previous family situation, employment, social activities and reproductive capabilities.

RESULTS

Continence status at discharge was largely maintained at 6 months and quality of life was improved. Many of those incontinent on discharge improved; a small number apparently cured at discharge had later recurrence of incontinence.

CONCLUSIONS

Surgical treatment for obstetric fistula is successful in maintaining continence and improving quality of life of women at 6-months follow up.

Proposal for a tiered approach to developmental toxicity testing for veterinary pharmaceutical products for food-producing animals

In order to establish the safety of veterinary drug residues in human food, a number of toxicological evaluations are required, including the assessment of potential risks to development. In the light of the use of developmental toxicity testing for risk characterization, we evaluated whether conducting these tests in more than one species was redundant. Review of the published Summary Reports of recommendations of the EU Committee for Veterinary Medicinal Products supplemented with data from the Joint FAO/WHO Expert Committee on Food Additives (JECFA) reports on veterinary drug residues in food identified 120 compounds, of which 105 had teratogenicity information in more than one species. The analysis of these compounds, representing a variety of chemical and pharmacological classes, provided justification for consideration of the use of a tiered approach for developmental toxicity evaluation of veterinary drugs for food-producing animals. The tiered approach begins with developmental toxicity testing in a rodent species, preferably the rat. If teratogenicity is observed, no testing in a second species would be required, except under specific circumstances where the ADI is determined based on the NOEL from this study. If a negative or an equivocal result for teratogenicity were observed in the rodent, then a developmental test in a second species, preferably the rabbit, would be conducted. The tiered approach provides thorough hazard identification, based on the use of a second species for compounds negative for teratogenicity in the rodent, and maintains maximum public protection based on the extremely low potential for human exposure to these compounds, while making a genuine attempt to limit unnecessary animal testing.

Risk factors for developing residual urinary incontinence after obstetric fistula repair

Obstetric vesicovaginal fistula is a devastating cause of urinary incontinence worldwide. More attention is being focused on treating these patients by various philanthropic societies but very little is known about the complications of surgery. One of the most common complications is that the woman is left with residual urinary incontinence despite the defect being successfully closed. If risk factors for this could be identified, then perhaps more appropriate surgical techniques could be developed with the aim of remedying the incontinence.

The neurophysiology of taste and olfaction in primates, and umami flavor

To investigate the neural encoding of glutamate (umami) taste in the primate, recordings were made from taste responsive neurons in the cortical taste areas in macaques. Most of the neurons were in the orbitofrontal cortex (secondary) taste area. First, it was shown that there is a representation of the taste of glutamate which is separate from the representation of the other prototypical tastants sweet (glucose), salt (NaCl), bitter (quinine) and sour (HCl). Second, it was shown that single neurons that had their best responses to sodium glutamate also had good responses to glutamic acid. Third, it was shown that the responses of these neurons to the nucleotide umami tastant inosine 5'-monophosphate were more correlated with their responses to monosodium glutamate than to any prototypical tastant. Fourth, concentration response curves showed that concentrations of monosodium glutamate as low as 0.001 M were just above threshold for some of these neurons. Fifth, some neurons in the orbitofrontal region, which responded to monosodium glutamate and other food tastes, decreased their responses after feeding with monosodium glutamate to behavioral satiety, revealing a mechanism of satiety. In some cases this reduction was sensory-specific. Sixth, it was shown in psychophysical experiments in humans that the flavor of umami is strongest with a combination of corresponding taste and olfactory stimuli (e.g., monosodium glutamate and garlic odor). The hypothesis is proposed that part of the way in which glutamate works as a flavor enhancer is by acting in combination with corresponding food odors. The appropriate associations between the odor and the glutamate taste may be learned at least in part by olfactory to taste association learning in the primate orbitofrontal cortex.

Syphilitic acute posterior placoid chorioretinitis in nonimmuno-compromised patients

PURPOSE

To describe the clinical and angiographic features of three cases of secondary syphilis in immunocompetent patients, which presented as acute posterior placoid chorioretinitis (APPC) to the ophthalmologist.

METHODS

Interventional case series. The aetiology of the APPC was confirmed by serology to be secondary syphilis. Optical coherence tomography, electrophysiology, fundus fluorescein, and indocyanine green (ICG) angiography were performed at presentation and after resolution. Appropriate treatment for secondary syphilis was instituted in each patient.

RESULTS

The clinical features, fundus fluorescein and ICG angiography, multifocal electroretinography (mfERG), and optical coherence tomography findings of APPC are described. All three patients had a satisfactory resolution of the APPC with improvement in visual acuity.

CONCLUSIONS

APPC in secondary syphilis can occur even in immunocompetent patients. A high index of suspicion is required for early diagnosis of this condition resulting in a good visual outcome with adequate treatment. mfERG and optical coherence tomography are useful in the diagnosis and follow-up of these patients.

The impact of surgical treatment on the mental health of women with obstetric fistula

Obstetric fistula is estimated to affect 2 million women worldwide and has considerable social and psychological effects on affected individuals. In this prospective study, 51 consecutive women with obstetric fistula admitted to the Barhirdar Hamlin Fistula Centre in the north of Ethiopia were screened using the General Health Questionnaire (GHQ-28) for potential mental health disorder before and 2 weeks after fistula surgery. Prior to surgery, all women screened positive. By 2 weeks after, this had dropped to 36% (P = 0.005). 27% of the 45 women who were cured of their incontinence screened positive, while all 6 of those with severe residual incontinence continued to screen positive. We conclude that surgical treatment of obstetric fistula results in marked improvements in mental heath.

The study of thermal and gross morphologic properties of polyglycolic acid upon annealing and degradation treatments

The objective of this study is to alter the fiber morphology of a linear aliphatic polyester, polyglycolic acid, by annealing treatment and to examine the changes of its degradation properties. The annealing was done at 150 degrees C, 170 degrees C, and 190 degrees C, and the specimens were annealed in four different strained conditions, freely hung, 0, 1, and 10%. After annealing treatments, the specimens were subject to in vitro hydrolytic degradation by immersing them in phosphate-buffer solution of pH 7.4 at 37 degrees C for up to 28 days. The thermal properties and gross morphology of the specimens were obtained. It was found that annealing treatments resulted in initial higher levels of crystallinity, which, in turn, influenced the hydrolytic degradation of the fiber. Among all the annealing conditions, the freely hung specimens annealed at 190 degrees C exhibited the most pronounced annealing effect on hydrolytic degradation, and was consistent with the observed gross morphologic changes. The change in the characteristics of fiber structure (i.e., the return to the stage of less oriented conformation upon freely hung annealing) was thought to be the cause.

The effect of annealing treatments on the tensile properties and hydrolytic degradative properties of polyglycolic acid sutures

The purpose of this research was to examine the effect of annealing treatments on the mechanical properties of polyglycolic acid sutures, and their subsequent influence on PGA degradation properties. An attempt was made to develop a better understanding of the degradation mechanism of synthetic absorbable sutures, including the relationship of their structure, morphology, and mechanical properties. PGA sutures were annealed under selected axial strain (freely hung, 0%, 1%, 10%), at four temperatures (150 degrees C, 170 degrees C, 180 degrees C, 190 degrees C), and two times (5 and 20 min). The annealed PGA specimens were then subjected to hydrolysis in phosphate-buffer solutions (pH = 7.4) for up to 28 days at 37 degrees C. Tensile properties were used to evaluate the effect of annealing treatments. The data were subjected to statistical analysis using the SAS system. All of the one-, and many of the two- and three-factor interactions were found to be statistically significant. Annealing treatments did alter the mechanical properties of PGA sutures, as well as their degradation properties. Except for the increase in tenacity of samples with increasing percent extension, all other respects of the annealing treatments resulted in lower tenacity and breaking elongation when compared with the control samples. Sutures that have been exposed to any level of axial tension during annealing, however, exhibited a lower rate of hydrolytic degradation than the freely hung suture samples. The reduction of the characteristics of fiber structure due to the tendency of the tie-chain molecules to acquire the less constrained conformations and thus to bring the crystal blocks they connect back to the original arrangement before drawing is believed to be responsible for the freely hung specimens to behave quite differently from the clamped and stressed PGA samples.

Lack of value of the Martius fibrofatty graft in obstetric fistula repair

OBJECTIVE

To ascertain if the Martius graft is of benefit to successful surgical outcome in obstetric fistula repair.

METHOD

A retrospective analysis of 440 consecutive obstetric fistula repairs performed by the author in the Addis Ababa Fistula Hospital, Ethiopia or the Barhirdar Hamlin Fistula Center, Ethiopia, with or without the Martius fibrofatty graft. These were further divided into 13 subgroups of vesicovaginal fistula and all groups compared against two outcomes; fistula closure and presence of residual urethral incontinence following repair. Results were statistically analyzed with the Fisher's exact or Chi-squared test.

RESULTS

There was no statistical difference between groups with regards to breakdown of repair but a higher rate of residual incontinence in 3 subgroups with the Martius graft.

CONCLUSION

The Martius graft can be safely omitted from obstetric fistula repair if the surgeon is experienced, and performs the same type of repair as used in this analysis.

Short communication: The circumferential obstetric fistula: characteristics, management and outcomes

Obstetric vesicovaginal fistula is a tragic injury that is widespread in any country where access to emergency obstetric care is limited. More and more people are now interested in treating and caring for these women, but little is known about surgical management, and most operators have developed their own methods through years of experience. One of the more challenging cases to get a functional repair is in those women who have a circumferential defect in the bladder/urethra. This article analyses a series of 77 consecutive circumferential obstetric fistula cases operated in the Barhirdar Hamlin Fistula Centre by the author.

A new technique for the surgical management of urinary incontinence after obstetric fistula repair

Obstetric vesicovaginal fistula is a debilitating injury still occurring widely throughout the developing world. Fortunately, now more and more surgeons are becoming aware of this previously hidden problem, and many thousands of women are receiving treatment each year. What is difficult for the fistula surgeon are those women, who after having their vesicovaginal fistula successfully closed, return to their doctor, still just as incontinent as they were with the fistula still open. This study describes a new, simple and cheap surgical procedure that promises to improve the lot of these unfortunate women.

Facile hyperpolarization chemistry for molecular imaging and metabolic tracking of [1-13C]pyruvate in vivo

Hyperpolarization chemistry based on reversible exchange of parahydrogen, also known as Signal Amplification By Reversible Exchange (SABRE), is a particularly simple approach to attain high levels of nuclear spin hyperpolarization, which can enhance NMR and MRI signals by many orders of magnitude. SABRE has received significant attention in the scientific community since its inception because of its relative experimental simplicity and its broad applicability to a wide range of molecules, however in vivo detection of molecular probes hyperpolarized by SABRE has remained elusive. Here we describe a first demonstration of SABRE-hyperpolarized contrast detected in vivo, specifically using hyperpolarized [1-13C]pyruvate. Biocompatible formulations of hyperpolarized [1-13C]pyruvate in, both, methanol-water mixtures, and ethanol-water mixtures followed by dilution with saline and catalyst filtration were prepared and injected into healthy Sprague Dawley and Wistar rats. Effective hyperpolarization-catalyst removal was performed with silica filters without major losses in hyperpolarization. Metabolic conversion of pyruvate to lactate, alanine, and bicarbonate was detected in vivo. Pyruvate-hydrate was also observed as minor byproduct. Measurements were performed on the liver and kidney at 4.7 T via time-resolved spectroscopy and chemical-shift-resolved MRI. In addition, whole-body metabolic measurements were obtained using a cryogen-free 1.5 T MRI system, illustrating the utility of combining lower-cost MRI systems with simple, low-cost hyperpolarization chemistry to develop safe, and scalable molecular imaging.

Skin flap vaginal augmentation helps prevent and cure post obstetric fistula repair urine leakage: a critical anatomical analysis

Our aim was to describe a new surgical method for prophylaxis/cure of post obstetric fistula repair leakage based on restoring vaginal elasticity with Singapore skin flap. The rationale for this operation was based on the integral theory: scarring removes elasticity required for independent function of oppositely acting urethral closure forces so they become 'tethered, forcibly opening the urethra when give the signal to close'. Skin graft restores elasticity and closure. Used prophylactically with Goh type 4 fistula (n = 45), 46% were dry against an expected 19%. In patients with successful fistula closure, still with severe leakage (n = 24), 71% were dry against an expected 26%.

TWEETABLE ABSTRACT

Singapore skin flap restores elasticity and prevents and treats incontinence in patients with successful obstetric fistula repair.

Obstetric fistula: Clinical considerations in the creation of a new urethra and the management of a subsequent pregnancy

The paper presents two case studies to illustrate the complexity of repairing obstetric fistula (OF) with neourethral construction when complete circumferential destruction occurred. Using fictitious names, the author describes the personal story and contexts leading to OF development and depression, surgical options, and the prognosis of repair. These cases were documented at the Barhirdar Hamlin Fistula Center in Northern Ethiopia.

Effect of age related macular degeneration on the Eger macular stressometer photostress recovery time

AIM

To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function.

METHODS

EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with both forms of the condition (mean age 79 (SD 13) years). Measurements were made on two occasions separated by 1 year. Intrasession repeatability was assessed by repeating the measures after a 10 minute recovery period at the first visit. Distance visual acuity was measured with a logMAR chart, near visual acuity with a MNRead chart at 25 cm, contrast sensitivity with a Pelli-Robson chart, and the presence of central visual disturbance assessed with an Amsler grid. A questionnaire was used to assess self reported difficulties with glare recovery.

RESULTS

The average EMS recovery time was 11.0 (SD 8.9) seconds, decreasing by 1.6 (5.2) seconds on repeated measurement (p<0.05). EMS photostress recovery was not correlated with visual function measures or subjective difficulties with lights (p>0.05). EMS photostress recovery time did not predict those whose vision decreased over the following year compared with those among whom it remained stable.

CONCLUSIONS

The EMS test is not a useful tool in determining the severity or progression of AMD.

Interplay of Near-Zero-Field Dephasing, Rephasing, and Relaxation Dynamics and [1-13C]Pyruvate Polarization Transfer Efficiency in Pulsed SABRE-SHEATH

Hyperpolarized [1-13C]pyruvate is a revolutionary molecular probe enabling ultrafast metabolic MRI scans in 1 min. This technology is now under evaluation in over 30 clinical trials, which employ dissolution Dynamic Nuclear Polarization (d-DNP) to prepare a batch of the contrast agent; however, d-DNP technology is slow and expensive. The emerging SABRE-SHEATH hyperpolarization technique enables fast (under 1 min) and robust production of hyperpolarized [1-13C]pyruvate via simultaneous chemical exchange of parahydrogen and pyruvate on IrIMes hexacoordinate complexes. Here, we study the application of microtesla pulses to investigate their effect on C-13 polarization efficiency, compared to that of conventional SABRE-SHEATH employing a static field (∼0.4 μT), to provide the matching conditions of polarization transfer from parahydrogen-derived hydrides to the 13C-1 nucleus. Our results demonstrate that using square-microtesla pulses with optimized parameters can produce 13C-1 polarization levels of up to 14.8% (when detected, averaging over all resonances), corresponding to signal enhancement by over 122,000-fold at the clinically relevant field of 1.4 T. We anticipate that our results can be directly translated to other structurally similar biomolecules such as [1-13C]α-ketoglutarate and [1-13C]α-ketoisocaproate. Moreover, other more advanced pulse shapes can potentially further boost heteronuclear polarization attainable via pulsed SABRE-SHEATH.

Failure of lactoperoxidase to iodinate specifically the plasma membrane of cucurbita tissue segments

An attempt has been made to use lactoperoxidase-catalyzed iodination of excised Cucurbita hypocotyl hooks to monitor the distribution of plasma membrane fragments relative to that of phytochrome in particulate fractions from this tissue. Upon fractionation, the iodinated tissue yields a 20,000g pellet which contains 58% of the trichloroacetic acid-precipitable (125)I at a specific radioactivity 12 times that of the proteins in the supernatant. On sucrose gradients, the labeled fraction has a mean isopycnic density of 1.15 g . cm(-3). The distribution profile is distinct from that of the total particulate protein and does not coincide with either mitochondrial or endoplasmic reticulum markers. These observations satisfy operational criteria commonly accepted in other systems as indices of selective labeling of the cell surface. The sucrose gradient profiles of the phytochrome and (125)I in the 20,000g pellets are noncoincident. In the absence of more direct evidence, this is readily interpreted to indicate a lack of association of the pigment with the plasma membrane.Autoradiographic analysis indicates, however, that the (125)I is almost exclusively associated with an amorphous film (possibly phloem-exudate protein) overlying the cut cells at the point of prelabeling excision and along the outer physical surface of the hypocotyl cuticle. No evidence of plasma membrane labeling is apparent. The observed membrane-like behavior of the iodinated material upon cell fractionation is attributed to the preferential posthomogenization association of this material with a particular membrane fraction(s). These data indicate that in addition to the well recognized potential for spurious labeling of the internal cytoplasmic proteins of leaky cells, a further source of ambiguity in surface-labeling experiments should be considered. That is, the potential for labeling extracellular proteins of nonplasma membrane origin but with a capacity to become associated with membranes upon homogenization.

Hyperpolarization of common antifungal agents with SABRE

Signal amplification by reversible exchange (SABRE) is a robust and inexpensive hyperpolarization (HP) technique to enhance nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) signals using parahydrogen (pH2 ). The substrate scope of SABRE is continually expanding. Here, we present the polarization of three antifungal drugs (voriconazole, clotrimazole, and fluconazole) and elicit the detailed HP mechanisms for 1 H and 15 N nuclei. In this exploratory work, 15 N polarization values of ~1% were achieved using 50% pH2 in solution of 3-mM catalyst and 60-mM substrate in perdeuterated methanol. All hyperpolarized 15 N sites exhibited long T1 in excess of 1 min at a clinically relevant field of 1 T. Hyperpolarizing common drugs is of interest due to their potential biomedical applications as MRI contrast agents or to enable studies on protein dynamics at physiological concentrations. We optimize the polarization with respect to temperature and the polarization transfer field (PTF) for 1 H nuclei in the millitesla regime and for 15 N nuclei in the microtesla regime, which provides detailed insights into exchange kinetics and spin evolution. This work broadens the SABRE substrate scope and provides mechanistic and kinetic insights into the HP process.