Methane- and dissolved organic carbon-fueled microbial loop supports a tropical subterranean estuary ecosystem.

Subterranean estuaries extend inland into density-stratified coastal carbonate aquifers containing a surprising diversity of endemic animals (mostly crustaceans) within a highly oligotrophic habitat. How complex ecosystems (termed anchialine) thrive in this globally distributed, cryptic environment is poorly understood. Here, we demonstrate that a microbial loop shuttles methane and dissolved organic carbon (DOC) to higher trophic levels of the anchialine food web in the Yucatan Peninsula (Mexico). Methane and DOC production and consumption within the coastal groundwater correspond with a microbial community capable of methanotrophy, heterotrophy, and chemoautotrophy, based on characterization by 16S rRNA gene amplicon sequencing and respiratory quinone composition. Fatty acid and bulk stable carbon isotope values of cave-adapted shrimp suggest that carbon from methanotrophic bacteria comprises 21% of their diet, on average. These findings reveal a heretofore unrecognized subterranean methane sink and contribute to our understanding of the carbon cycle and ecosystem function of karst subterranean estuaries.

Analysis of adventitious lung sounds originating from pulmonary tuberculosis.

Tuberculosis is a common and potentially deadly infectious disease, usually affecting the respiratory system and causing the sound properties of symptomatic infected lungs to differ from non-infected lungs. Auscultation is often ruled out as a reliable diagnostic technique for TB due to the random distribution of the infection and the varying severity of damage to the lungs. However, advancements in signal processing techniques for respiratory sounds can improve the potential of auscultation far beyond the capabilities of the conventional mechanical stethoscope. Though computer-based signal analysis of respiratory sounds has produced a significant body of research, there have not been any recent investigations into the computer-aided analysis of lung sounds associated with pulmonary Tuberculosis (TB), despite the severity of the disease in many countries. In this paper, respiratory sounds were recorded from 14 locations around the posterior and anterior chest walls of healthy volunteers and patients infected with pulmonary TB. The most significant signal features in both the time and frequency domains associated with the presence of TB, were identified by using the statistical overlap factor (SOF). These features were then employed to train a neural network to automatically classify the auscultation recordings into their respective healthy or TB-origin categories. The neural network yielded a diagnostic accuracy of 73%, but it is believed that automated filtering of the noise in the clinics, more training samples and perhaps other signal processing methods can improve the results of future studies. This work demonstrates the potential of computer-aided auscultation as an aid for the diagnosis and treatment of TB.

[Isolated congenital lower lip fistulas]. / Isolierte kongenitale Unterlippenfisteln.

BACKGROUND: Congenital lip fistulas are very rare and may occur alone or in combination with oral clefts and other dysontogenetic malformations. The etiology of congenital lip fistulas is not yet known. PATIENT AND METHOD: We present a 7-year-old boy with recurrent infections of bilateral congenital fistulas of the lower lip. There were no associated congenital anomalies and a negative family history. An elliptical excision of the fistulas under microscopic control gave satisfactory functional and esthetic results. There was no recurrence two years after surgery. CONCLUSION: Since the possibility of additional severe malformations exists for the patient and the patient's children patients should undergo careful ENT and pediatric assessment, and genetic counselling should be considered. In order to achieve good functional and esthetic results, the corrective operation must be planned carefully taking into consideration important surgical principles.

[Intrastromal keratorhexis with the Nd:YAG laser--a possible method of refractive surgery?]. / Intrastromale Keratorhexis mit dem Nd:YAG-Laser--ein möglicher Weg der refraktiven Chirurgie?

A new method of refractive corneal surgery is presented. With the q-switched Nd:YAG-laser Visulas (Zeiss-Oberkochen) we succeed in altering the optical power of the cornea of rabbits, pigs and humans. The number of applied laser spots and the distribution pattern influence the way and the amount of change of refraction. The method, clinical and histological features, complications and prospects of the Nd: YAG laser keratorhexis are described.

A contribution to the scientific assessment of degenerative and regenerative processes of peripheral nerve fibers following axonotmesis under the systemic administration of vitamins B1, B6 and B12--light and electron microscopy findings of the saphenous nerve in the rabbit.

The present study investigates the de- and regenerative changes in the saphenous nerve of the rabbit following systemic treatment with a combination of the vitamins B1, B6 and B12 and a control group that was treated with physiological saline solution. Cold lesion of the nerve, which led to an optimal axonotmesis, was used to cause a secondary degeneration. After 4, 10 and 21 days the nerves were removed and investigated by light and electron microscopy. The morphological results show that the number of regenerating axons is higher and that of degenerating axons lower in the group treated with the given doses of the vitamins than in the comparable control group. Statements as to the metabolic processes and vitamins from which the better regeneration results are due are as yet not possible. Further investigations with the individual vitamins are necessary. Clinical indications of neurotoxicity due to the dose levels used were not observed in any of the cases.

[Modification of degenerative and regenerative processes in peripheral nerves by treatment with B vitamins]. / Beeinflussung der degenerativen und regenerativen Vorgänge an peripheren Nerven unter Behandlung mit B-Vitaminen.

Degenerative and regenerative changes in the saphenous nerve of the rabbit following systemic treatment with either a combination of the vitamins B1, B6 and B12 or physiological saline solution were investigated. Cold lesion of the nerve (-196 degrees C), which led to an optimal axonotmesis, was used to cause a secondary degeneration. The nerves were removed and investigated by light and electron microscopy after 4, 10 and 21 days. Morphological results show that the number of regenerating axons is higher and that of degenerating axons lower in the group treated with the given doses of vitamins than in the comparable control group. An explanation of the underlying metabolic processes is as yet not possible. Further investigations considering the contribution of the individual vitamins to the enhancement of degenerative and regenerative processes are necessary. Clinical indications of neurotoxicity due to the dose levels used here were not observed.

[Effect of locally applied corticoids on the morphology of peripheral nerves following neurotmesis and microsurgical suture]. / Einfluss lokal applizierter Kortikoide auf die Morphologie peripherer Nerven nach Neurotmesis und mikrochirurgischer Naht.

The present work deals with the morphology of cut peripheral nerves anastomosed by primary microsurgical suture. The important question was whether the well-known anti-inflammatory, anti-exudative and fibroblast-inhibiting effects of locally applied glucocorticoids can influence the morphology of degenerating and regenerating peripheral nerves. After cutting the saphenous nerve of the rabbit and prior to its microsurgical suture the synthetic crystalline glucocorticoids methylprednisolone, prednisolone and dexamethasone were applied between the distal and proximal nerve stumps (interfascicular surface application). After a defined time of two days up to a maximum of five weeks the suture site and adjacent parts of the nerve were removed and investigated by light microscopy and electron microscopy. The morphological findings of the degenerating and regenerating nerve structures with and without local application of the different corticoids were compared. The results show that after local application of glucocorticoids the formation of scar tissue and neuromata is decreased, thus supporting the processes of regeneration. This is a result of a reduction of fibroblasts in the new formation of the epineurium and in the endoneurium and a certain protective effect on the perineural cells. Furthermore, the application of the glucocorticoids seems to accelerate the breaking down of myelin and degenerating axons and the new formation of myelin sheaths by "activating" Schwann cells. These facts lead to an enhancement of nerve regeneration after microsurgical suture.