In oculo transplants of myometrium from postpartum guinea pigs fail to support sympathetic reinnervation

Sympathetic nerves to the enlarged fetus-containing region of the uterus undergo degenerative changes during late pregnancy and show slow regrowth after parturition. It is not known whether this unusual response of sympathetic nerves to smooth muscle hypertrophy is due to the sensitivity of short adrenergic neurons to hormonal changes, or whether the nerves respond to changes in the neurotrophic capacity of the target. We have investigated this question using in oculo transplantation. Small pieces of myometrium from the uterine horn of virgin guinea pigs, or from the region previously occupied by the placenta and fetus in postpartum guinea pigs, were transplanted into the anterior eye chamber. After 3 wk in oculo, the pattern of reinnervation of the transplants was assessed on whole mount stretch preparations stained for tyrosine hydroxylase. The histology of the transplants was examined in toluidine blue-stained semithin sections. Myometrial transplants from virgin donors and uterine artery transplants from both virgin and postpartum donors became organotypically reinnervated by sympathetic fibres from the host iris. In contrast, sympathetic nerves did not reinnervate myometrial transplants from postpartum donors, although they approached the transplants and became distributed in the surrounding connective tissue. All transplanted tissues showed a normal histological appearance. Both the myometrium and uterine artery from postpartum donors retained a hypertrophic appearance after 3 wk in oculo. We interpret these results to indicate that the degeneration of sympathetic nerves in late pregnancy, as well as their slow regrowth to the uterus after delivery, may be due to changes in uterine smooth muscle rather than a particular sensitivity of short adrenergic neurons to hormonal changes.     

Somatosensory mismatch negativity in healthy children

Aim  Event-related potentials (ERPs) obtained when focused attention is kept away from the stimulus (unnoticed stimulation) are possibly linked to automatic mismatch-detection mechanisms, and could be a useful tool to investigate sensory discrimination ability. By considering the high impact of impaired somatosensory integration on many neurological disturbances in children, we aimed to verify whether mismatch-related responses to somatosensory stimulation could be obtained in healthy children.
Method  Eleven healthy participants (age range 6–11y, mean 8y 2mo, SD 1y 7mo; seven males, four females) underwent 'oddball' electrical stimulation of the right hand (80% frequent stimuli delivered to the thumb, 20% deviant stimuli delivered to the fifth finger). Data were compared with those obtained when the frequent stimuli to the thumb were omitted ('standard-omitted' protocol). ERPs were recorded at frontal, central, and parietal scalp locations. Children's overt attention was engaged by a demanding video game.
Results  In the oddball protocol, deviant stimulation elicited a left central negativity at about 160ms latency, followed by a left frontal negative response at about 220ms latency. Standard-omitted traces showed only a left parietal negative response spreading to right parietal regions.
Interpretation  Mismatch-related somatosensory responses can be reliably obtained in children, providing that appropriate technical contrivances are used. In clinical use, the frontal components, which are present only during the oddball protocol, could be a reliable and unequivocal neurophysiological marker of the automatic mismatch-detection mechanism.     

Screening for multiple somatic complaints in a population-based survey: Does excessive symptom reporting capture the concept of somatic symptom disorders? : Findings from the MONICA-KORA Cohort Study

Objective

Excessive symptom reporting (ESR) has gained a revived attention in the conceptualization of somatic symptom disorders. We aimed to explore whether ESR captures the concept of somatic symptom disorders regardless of the patient's disease status or the degree of symptom burden.

Methods

In three independent cross-sectional population-based samples of the MONICA/KORA Study in 1985, 1990, and 1995, somatic symptom reporting and an array of somatic and mental health features were assessed in 11,895 eligible participants. After a mean 12-year follow-up, the vital status was assessed at the end of 2002. All-cause mortality was calculated as hazard risks ratios (HRs).

Results

Among all participants, a total of 1238 men and 1169 women were in the sex-specific upper quintile of the somatic symptom distribution and qualified for ESR subpopulation. ESR participants were older, on a lower educational level, and more often unemployed. They suffered more often from metabolic syndrome and chronic diseases. ESR was associated with psychological distress, negative self-perceived health, and sleeping disorders. ESR was associated with twofold more ambulant and hospital medical utilization. Survival in ESR participants was significantly reduced (HR=1.33; 95% CI=1.18-1.49; P<.001). Frequency of medical ambulatory consultations and days in hospital were higher in ESR participants, even after controlling for potential confounders.

Conclusion

A simple approach to screen for participants with high symptom reporting in an unselected population-based sample results in the identification of a clinically meaningful target population with high burden of physical and psychological comorbidities.     

A novel algorithm for the coupling control in solid-phase peptide synthesis

This paper describes a new method for the evaluation of conductimetric data collected during the in-line monitoring of the coupling step in solid-phase peptide synthesis. The control scheme relies on a feed-forward artificial neural network algorithm which can predict the final yield of the reaction within its initial 5 min by analyzing the conductivity signal profile. The yield values predicted by the artificial neural network algorithm result in good accordance with the data obtained by the commonly used ninhydrin test. © Munksgaard 1997.     

SPPS of difficult sequences

The H-Ala-Arg-(Ala)₆-Lys-OH sequence is a biologically interesting ‘difficult sequence’ presenting N^α-Fmoc deprotection and coupling problems. Different chemical conditions and synthetic strategies have been tested in order to overcome the problems due to sequence-dependent interactions. In particular, it was confirmed that different solvents in the deprotection step did not provide any significant improvement, but the use of a more efficient base in the deprotection mixture avoided insufficient unblocking of N^α-protecting group; problems due to partial coupling in the last steps of the synthesis were solved by double coupling techniques. Moreover, the synthesis of the model peptide was carried out using both ‘continuous flow’ and ‘batch’ techniques. The present results demontrate that on-line monitoring of the deprotection step by absorbance measurements represents a very effective tool to detect the onset of internal aggregations during the synthesis. © Munksgaard 1997.