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Multiple investigators have suggested that the benthic flux of dissolved iron (Fed) from continental shelf sediments represents an important source of this micronutrient to ocean waters. The magnitude, biogeochemical controls, and seasonal dynamics of Fed fluxes to date, however, have mostly been studied for muddy cohesive sediments dominated by molecular diffusion. Data from these studies have been included in global biogeochemical models to determine the contribution of this Fe source to the ocean. Fed fluxes from sandy advective sediments have received little consideration, although these sediments cover 50–60 % of the continental shelves. Sandy permeable deposits function as dynamic catalytic filters characterized by the rapid exchange of solutes and infiltration of particles —including labile Corg and reactive metal oxides— and high biogeochemical reaction rates. In this article, we discuss how the fundamentally different modes of solute and particle transport in sands affect the sedimentary Fe cycle and Fed flux. We present a case study in which we simulate bioirrigation in sands in summer and winter. In our experiments, Fed fluxes from non-irrigated sediments under diffusive conditions did not exceed 6 and 13 μmol Fe m-2 d-1 in winter and summer, respectively. Fluxes from irrigated cores reached values of 150 μmol Fe m-2 d-1 (winter) and 115 μmol Fe m-2 d-1 (summer). The results indicate that the pumping activity of the benthic macrofauna plays a key role in controlling the extent of the benthic Fed flux from permeable sediments, and that both biogenic and physical advection enhance fluxes. We argue that bioturbated sandy advective sediments constitute an important benthic Fe source to coastal waters and advocate for a more differentiated treatment of sediment type (muddy diffusive vs. sandy advective) and macrofaunal activity -reflecting different functional groups of the macrobenthos- in global biogeochemical Fe models. A better understanding of the benthic Fe cycle in sandy advective sediments is particularly important to help predict how anthropogenic effects such as changes in the deposition patterns of Corg and metals, the expansion of oxygen minimum zones, and changes in benthic biodiversity will affect the tightly coupled benthic-pelagic ecosystem along continental shelves.

Ambient-stable fluorescent radicals have recently emerged as promising luminescent materials; however, tailoring their properties has been difficult due to the limited photophysical understanding of open-shell organic systems. Here we report the experimental and computational analysis of a redox pair of π-conjugated fluorescent molecules that differ by one electron. A π-dication (DC) and π-radical cation (RC) demonstrate different absorption spectra, but similar red emission (λemiss,max = ∼630 nm), excitation maxima (λexc,max = ∼530 nm), fluorescence lifetimes (1–10 ns), and even excited-state (non-emissive) lifetimes when measured by transient absorption spectroscopy. Despite their experimental similarities, time-dependent density functional theory (TDDFT) studies reveal that DC and RC emission mechanisms are distinct and rely on different electronic transitions. Excited-state reorganization occurs by hole relaxation in singlet DC, while doublet RC undergoes a Jahn-Teller distortion by bending its π-backbone in order to facilitate spin-pairing between singly occupied molecular orbitals. This relationship between the excited-state dynamics of RC and its π-backbone geometry illustrates a potential strategy for developing π-conjugated radicals with new emission properties. Additionally, by comparing TDDFT and CIS (configuration interaction singles) excitations, we show that unrestricted TDDFT accurately reproduces experimental absorption spectra and provides an opportunity to examine the relaxed excited-state properties of large open-shell molecules like RC., Experimental and computational studies reveal mechanistic differences in the photophysics of an open- versus closed-shell π-conjugated redox pair.

By stabilizing unpaired spin in the ground state, open-shell π-conjugated molecules can achieve optoelectronic properties that are inaccessible to closed-shell compounds. Here, we report the synthe...

By stabilizing unpaired spin in the ground state, open-shell π-conjugated molecules can achieve optoelectronic properties that are inaccessible to closed-shell compounds. Here, we report the synthesis and characterization of a

Open-shell, π-conjugated molecules represent exciting next-generation materials due to their unique optoelectronic and magnetic properties and their potential to exploit unpaired spin densities to engineer exceptionally close π-π interactions. However, prior syntheses of ambient stable, open-shell molecules required lengthy routes and displayed intermolecular spin-spin coupling with limited dimensionality. Here we report a general fragment-coupling strategy with phenalenone that enables the rapid construction of both biradicaloid (Ph2- s-IDPL, 1) and radical [10(OTf)] bisphenalenyls in ≤7 steps from commercial starting materials. Significantly, we have discovered an electronically stabilized π-radical cation [10(OTf)] that shows multiple intermolecular closer-than-vdW contacts (

Aim Surgical closure of high or complex anal fistulae is often a difficult challenge. A special Nitinol clip, the OTSC clip (Ovesco AG), was evaluated for fistula closure in a porcine model. Method A total of 20 fistulae were created in 10 animals by seton insertion. Four weeks after fistula induction the setons were removed: one internal fistula opening per animal was left untreated as control whereas the other opening was closed by the OTSC clip using a specially developed transanal clip applicator. The safety and technical feasibility of the clip application were tested. Another 4 weeks later, fistulae were macroscopically assessed for closure. For histological examination, the anorectum including the fistula tract was excised en bloc. Results Four weeks after clip placement, all external and internal fistula openings were macroscopically closed. The clip application site presented with an increased scarring. Microscopically, 40% of residual tracts and a more intense chronic inflammation were seen in the untreated control fistulae. After clip placement, 10% of the fistulae persisted associated with a higher density of collagen fibres indicating a better fistula scarring and healing. No unexpected side-effects or complications caused by the clip were observed. Conclusion Fistula closure using the OTSC clip represents a promising sphincter-preserving minimally invasive procedure. This study demonstrated the safety and feasibility of the ‘anal fistula claw’ for fistula closure. In spite of limitations of the porcine model the results justify clinical applications and further investigations.

Background: Gastrinomas are the most frequent hormonally-active neuroendocrine tumours in patients with multiple endocrine neoplasia type 1 (MEN1). Case Report: We report on the diagnostic difficulties in a 62-year-old female patient with MEN1 and lymph node gastrinoma. At six and twelve months after resection of a lymph node gastrinoma, no signs of recurrence were observed. Basal and peak gastrin levels during secretin stimulation test were normalized. Extensive explorations, including gastrointesinal endoscopy, endoscopic ultrasonography, and Ga-68-DOTATOC-PET/CT, did not reveal a primary duodenal or pancreatic tumour. Conclusion: Localization of gastrinomas in patients with MEN1 is challenging due to their small size, frequent duodenal location, and multiplicity. Therefore, while some studies support the existence of primary lymph node gastrinoma in patients with sporadic disease, this diagnosis should not be made in MEN1 patients. In both cases, however, extensive follow-ups are required.

Wound-healing mechanisms change during transition from prenatal to postnatal stage. Cytokines are known to play a key role in this process. The current study investigated the differential cytokine activity and healing morphology during healing of incisional skin wounds in rats of the ages neonatal (p0), 3 days old (p3) and adult, after six different healing times (2 hrs to 30 days). All seven tested cytokines (Transforming Growth Factor (TGF) alpha, TGFbeta1, -beta2 and -beta3, IGF 1, Platelet Derived Growth Factor A (PDGF A), basic Fibroblast Growth Factor (bFGF) exhibited higher expression in the adult wounds than at the ages p0 and p3. Expression typically peaked between 12 hrs and 3 days post-wounding, and was not detectable any more at days 10 and 30. The neonate specimen showed more rapid re-epithelialization, far less inflammation and scarring, and larger restitution of original tissue architecture than their adult counterparts, resembling a prenatal healing pattern. The results may encourage the use of neonatal rat skin as a wound-healing model for further studies, instead of the more complicated prenatal animal models. Secondly, the data may recommend inhibition of PDGF A, basic FGF or TGF-beta1 as therapeutic targets in efforts to optimize wound healing in the adult organism.

Ectopic ACTH syndrome is a rare differential diagnosis of hypokalemic hypertension. Patients with ectopic ACTH syndrome due to small cell lung cancer have a poor prognosis. We report on a 68-year-old female patient who presented with dyspnea and hypokalemic hypertension. Endocrine testing was consistent with ectopic ACTH syndrome due to small cell lung cancer. After initiation of chemotherapy with etoposide and carboplatin ACTH and cortisol levels normalized and clinical symptoms impressively improved.

We present a case of unusual distribution of red marrow in a patient with extramedullary acute myelogenous leukemia (AML). In adults, hematopoietic marrow is usually located in the axial skeleton and the proximal aspects of the limbs, except for the epiphyses. Nodular islets of red marrow located in the epiphyseal and distal parts of the limbs may mimic tumoral infiltration and be mistaken for chloroma in a patient with AML.

We report a rare case of primary aldosteronism due to an adrenocortical carcinoma. A 61-year-old woman with a history of hypertension and hypokalemia was referred for evaluation of a 4.2 cm measuring adrenal mass without secondary signs of malignancy. Endocrinological testing was consistent with primary aldosteronism. The patient underwent surgical resection of the adrenal mass; histology revealed an adrenocortical carcinoma. Postoperatively blood pressure, serum potassium, and aldosterone returned to normal. Four months after adrenalectomy, the patient presented again with hypokalemic hypertension and was found to have metastatic disease. Endocrinological investigation revealed primary aldosteronism and subclinical autonomous glucocorticoid hypersecretion. Careful hormonal investigation should be obtained in patients with adrenal masses causing excessive aldosterone secretion. In uncertain cases of primary aldosteronism, we would suggest to measure 18-hydroxy-cortisol levels, as excessive amounts may indicate adrenocortical carcinoma.

Besides being an antiprogestin, mifepristone (RU 486) was recently shown to antagonize oestrogen-dependent growth in the endometrium. To explore the molecular mechanisms for this phenomenon, we investigated whether or not the morphological effects of mifepristone are mediated by the progesterone receptor (PR) and whether mifepristone has disparate effects on the glandular epithelium and stroma. Six groups of hypogonadal, oestrogen-primed cynomolgus monkeys were treated for 2 weeks with: vehicle only (group I); mifepristone (group II); mifepristone plus progesterone at 0.2 mg/kg (group III), 1.0 mg/kg (group IV) or 5.0 mg/ kg (group V); and progesterone only (5.0 mg/kg) (group VI). Histomorphological evaluation showed strikingly compacted stroma in the mifepristone-exposed endometria (group II), which was partially reversible by additional progesterone treatment (groups III-V). Glandular proliferation (pseudostratification, glandular mitoses) in mifepristone-treated monkeys was not significantly different from that in vehicle (oestradiol)-treated monkeys, but was inhibited by progesterone-only treatment. Cells containing vacuoles were scarce in the mifepristone-exposed endometrium, but detected frequently in progesterone-exposed endometria, indicating the strong antisecretory effect of mifepristone on glands. We conclude that oestrogen-dependent oedema in the stroma is antagonized by mifepristone. The reversal of this effect by progesterone suggests a PR-mediated mechanism. In glands, mifepristone is antiprogestogenic, but not antioestrogenic. Thus, stromal cells may be the target of antiprogestin-induced inhibition of oedema and endometrial growth.

PURPOSE Evaluation of the potential of various MR techniques to differentiate bladder wall layers verified by histological findings. MATERIAL AND METHOD 6 bladder specimens of pigs were examined in vitro using T1-weighted spin-echo-sequences, T2-weighted Turbo-SE, fat suppressed T2-weighted SE, and inversion recovery sequences. The MR images were obtained before and after fixating the specimens in formalin. Measurements of the thickness of bladder wall layers were performed on both sets of MR images as well as on histological sections, RESULTS T2-weighted SE images showed three layers of different signal intensities: one innermost band of very high signal, one inner band of low and one outer band of intermediate signal corresponding histologically tunica propria and two different muscle layers. Inversion recovery technique provided similar findings but were able to avoid chemical-shift artifacts. After 24 hours in formalin, the signal intensity relation of the two muscle layers was inverted. The thickness of total bladder wall was not reduced significantly. Concerning the thickness of urinary bladder wall, histological measurements and evaluation of MR images correlated well. CONCLUSION MR imaging enables the differentiation of three bladder wall layers. Inversion recovery technique achieved the best image quality by avoiding chemical shift artifact.

Surgical closure of high or complex anal fistulae is often a difficult challenge. A special Nitinol clip, the OTSC clip (Ovesco AG), was evaluated for fistula closure in a porcine model.A total of 20 fistulae were created in 10 animals by seton insertion. Four weeks after fistula induction the setons were removed: one internal fistula opening per animal was left untreated as control whereas the other opening was closed by the OTSC clip using a specially developed transanal clip applicator. The safety and technical feasibility of the clip application were tested. Another 4 weeks later, fistulae were macroscopically assessed for closure. For histological examination, the anorectum including the fistula tract was excised en bloc.Four weeks after clip placement, all external and internal fistula openings were macroscopically closed. The clip application site presented with an increased scarring. Microscopically, 40% of residual tracts and a more intense chronic inflammation were seen in the untreated control fistulae. After clip placement, 10% of the fistulae persisted associated with a higher density of collagen fibres indicating a better fistula scarring and healing. No unexpected side-effects or complications caused by the clip were observed.Fistula closure using the OTSC clip represents a promising sphincter-preserving minimally invasive procedure. This study demonstrated the safety and feasibility of the 'anal fistula claw' for fistula closure. In spite of limitations of the porcine model the results justify clinical applications and further investigations.

This experimental study was designed to define the potential value of a mid-infrared holmium laser in the free running mode for angioplasty. Immediately after removal, fresh normal and diseased human cadaveric arteries were irradiated under saline with a Ho:YAG laser (wavelength 2.13 μm). The laser was pulsed at 3 Hz, 250 μs pulse width and fluences of 10 to 40 J/cm2. The laser beam was coupled to ring catheters with multiple low-OH quartz fibers. The tip of the delivery device was held in direct contact with the vessel surface with the laser beam oriented perpendicularly. Ablation of atherosclerotic plaque was accomplished at an ablation threshold of 10 J/cm2. The ablation rate was 2.1 to 8.3 μm/pulse. Removal of calcified plaque was only partially effective. There were marked thermal effects with vacuolizations extending up to 1505 ± 178 μm into the adjacent tissue. Laser light at the mid-infrared wavelength of 2.13 μm is supposed to be attractive as it is readily absorbed in water and can easily be transmitted through optical fibers. However, Q-switching seems to be essential to minimize thermal side effects and to make effective ablation of calcium possible.

This experimental study was designed to define the potential value of a mid-infrared holmium laser in the free running mode for angioplasty. Immediately after removal, fresh normal and diseased human cadaveric arteries were irradiated under saline with a Ho:YAG laser (wavelength 2.13 μm). The laser was pulsed at 3 Hz, 250 μs pulse width and fluences of 10 to 40 J/cm2. The laser beam was coupled to ring catheters with multiple low-OH quartz fibers. The tip of the delivery device was held in direct contact with the vessel surface with the laser beam oriented perpendicularly. Ablation of atherosclerotic plaque was accomplished at an ablation threshold of 10 J/cm2. The ablation rate was 2.1 to 8.3 μm/pulse. Removal of calcified plaque was only partially effective. There were marked thermal effects with vacuolizations extending up to 1505 ± 178 μm into the adjacent tissue. Laser light at the mid-infrared wavelength of 2.13 μm is supposed to be attractive as it is readily absorbed in water and can easily be tra...

This experimental study was designed to define the potential value of a mid-infrared holmium laser in the free running mode for angioplasty. Immediately after removal, fresh normal and diseased human cadaveric arteries were irradiated under saline with a Ho:YAG laser (wavelength 2.13 microns). The laser was pulsed at 3 Hz, 250 microseconds pulse width and fluences of 10 to 40 J/cm2. The laser beam was coupled to ring catheters with multiple low-OH quartz fibers. The tip of the delivery device was held in direct contact with the vessel surface with the laser beam oriented perpendicularly. Ablation of atherosclerotic plaque was accomplished at an ablation threshold of 10 J/cm2. The ablation rate was 2.1 to 8.3 microns/pulse. Removal of calcified plaque was only partially effective. There were marked thermal effects with vacuolizations extending up to 1505 +/- 178 microns into the adjacent tissue. Laser light at the mid-infrared wavelength of 2.13 microns is supposed to be attractive as it is readily absorbed in water and can easily be transmitted through optical fibers. However, Q-switching seems to be essential to minimize thermal side effects and to make effective ablation of calcium possible.

Investigation of renal biopsy specimens from 488 patients with diabetic glomerulosclerosis (DGS) of varying severity revealed the following: 1) The severity of DGS increases with the duration of the diabetes. 2) As the severity of DGS increases, it is complicated with increasing frequency by exudative changes, which correspond in detail to hyperperfusion lesions described in the literature. 3) As the severity of DGS increases, the severity of arteriolosclerosis and the incidence of nephrotic syndrome increase significantly. 4) The 5- and 10-year renal survival rates are highest for those diabetic patients in whom the tubules and renal cortical interstitium are of normal appearance. These survival rates are diminished if any of the following are present at the time of biopsy: a) interstitial fibrosis; b) hyperperfusion lesions; c) nephrotic syndrome; d) elevation of the serum creatinine concentration to more than 1.3 mg%. 5) No significant correlation was found between renal survival rate and age, sex, or type of diabetes. 6) The inflammation of the renal interstitium seen in diabetes does not differ from that seen in chronic glomerulonephritis. Monocytes, macrophages, T lymphocytes, fibroblasts and fibrocytes play the major role in this inflammation. This inflammatory process is considered to represent not pyelonephritis, but rather an auto-immune process. In other words, it is proposed that the diabetic kidney fails not only as a result of non-specific glomerular lesions (hyperperfusion lesions) but also because of non-specific tubulointerstitial changes, whereas diabetic glomerulosclerosis alone does not lead to chronic renal failure.

Hypercalcaemic crisis is a rare endocrine emergency. Often, an acute renal failure develops due to hypercalcaemia-induced polyuria. The molecular causes comprise stimulation of the calcium-sensing receptor in the ascending Henle loop and a reduced aquaporin expression in the collecting ducts. We report on a 54-year-old woman who was admitted for hypercalcaemic crisis and acute renal failure. Immediate rehydratation, bisphosphonate administration, and slow-extended daily dialysis (SLEDD) were initiated leading to a marked reduction of serum calcium. Endocrine work-up revealed primary hyperparathyroidism due to a parathyroid adenoma, which was treated by emergency surgery. Haemodialysis was continued in the first post-operative weeks for prolonged acute renal failure.

Aims: To study the range of differentiation and presence of cells positive for stem cell markers in 20 sacrococcygeal teratomas (SCTs) which were consecutively operated on between 1990 and 2000 in the Department of Paediatric Surgery in Tubingen, Germany. Methods and results: Preserved paraffin-embedded material was re-evaluated. In addition to tissues of various organs, caudal organ structures not described before were identified, such as colon with pancreas originating from colonic crypts, Fallopian tube and vaginal epithelia. The derivation of the latter was confirmed by Mullerian duct specific CA125 and CA19-9 antibodies. The expression of stem cell markers was studied with antibodies against nanog, Oct4, SSEA-4, nestin and subtype M3 muscarinic receptors. Cells positive for these markers were encountered in immature end buds and capillary sprouts, and as single cells in neural tissue, gonadal structures, hairs and in the stem cell niches of differentiated epithelia. Conclusions: Our data indicate that SCTs of the newborn arise from remnants of the epiblast-like tail bud blastema and demonstrate that they contain cells positive for embryonic stem cell markers and may represent a novel source for human embryonic stem cells.

We have carried out an experimental study using a new laser catheter on 28 cadaver femoral arteries in 14 subjects and on six aortas. This ring catheter system consists of 12 circular quartz fibres with a central lumen and allows the application of energies up to 20 mJ through a 7F flexible catheter in vivo. The laser emits ultraviolet light of a wave-length of 308 nm, in pulses of 60 ns and a frequency of 2-40 Hz. The energy within a single fibre is 5 J/cm2 and exceeds the intensity required to ablate calcifications. Histologically it has been shown that, depending on the type of tissue, 1 to 2.4 microns of tissue per pulse is removed. Experimentally, rate of progress in a calcified occlusive lesion in the femoral artery, using 20 Hz and energy transmission of 20 mJ, was 3 to 5 mm per minute. Perforation of vessel wall if the catheter tip was at right angles to it depended on the degree of atherosclerosis and was between nine and 116 seconds. Marginally, there was only minimal thermal damage.

Ectopic ACTH syndrome is a rare differential diagnosis of hypokalemic hypertension. Patients with ectopic ACTH syndrome due to small cell lung cancer have a poor prognosis. We report on a 68-year-old female patient who presented with dyspnea and hypokalemic hypertension. Endocrine testing was consistent with ectopic ACTH syndrome due to small cell lung cancer. After initiation of chemotherapy with etoposide and carboplatin ACTH and cortisol levels normalized and clinical symptoms impressively improved.

Die Implantation von Kunststoffnetzen in der Hernienchirurgie stellt ein effektives und etabliertes Verfahren dar. Im Gegensatz zu klinischen Daten des Reparationsergebnisses finden sich nur wenige Grundlageninformationen uber die histologische Reaktionsweise im Implantatbereich. Vollig unbekannt ist daruber hinaus ein Vergleich dieser speziellen Gewebsreaktion mit implantatfreien Narbengewebe. Methodik:Von 12/99 bis 06/01 wurden laparoskopisch oder konventionell Proben aus Implantatbereichen nach vorausgegangenen Hernienreparationen sowie von Narbengeweben nach Laparotomien in einer prospektiven Untersuchungsserie gewonnen. Die Proben wurden mittels konventionellen und immunhistochemischen Techniken (Anti-CD 3, -CD 20, -CD 68) analysiert. Gemessen wurde ebenso mit Hilfe von Proliferationsmarkern (Anti Ki 67) und Tumorsupressorantigen (Anti-P53). Ergebnisse:Insgesamt wurden 109 Gewebeproben untersucht. In 70 Fallen wurde eine Netzprobe aus dem Implantatbereich entnommen, wobei in 28 Fallen (40%) eine Rezidivhernie vorlag. Die mediane Implantationsdauer betrug 32,4 (0,5 - 78,7) Monate. Bei 29 Patienten wurde ausschlieslich Narbengewebe im Median 22,0 (2,5 - 1220,7) Monate nach der Primarlaesion untersucht. Ab 4 Monaten findet sich bis zum langsten Beobachtungsintervall eine konstante resorptive Entzundung mit Fremdkorperriesenzellen und immunologischer Reaktion (B- und T-Lymphozyten) um die Netz-Filamente mit umgebenden zellarmen Narbengewebe. Es besteht keine gesteigerte Proliferationsrate und keine uberexpression des Tumorsupressorgens P 53. Schlusfolgerung:Durch die Netzimplantation resultiert im Gegensatz zum netzfreien Narbengewebe im Implantatlager eine zellulare Reaktion vom Fremdkorpertyp. Diese nimmt nach der Implantation zunachst deutlich ab, persistiert dann jedoch. Anhand dieser Ergebnisse finden sich derzeit keine Hinweise fur ein erhohtes Entartungsrisiko. Molekularbiologische Untersuchungen auf genomische Aberration werden zur Zeit durchgefuhrt.

We present the case of a 71-year-old woman who was hospitalized because of a severe hip contusion. She had no symptoms or clinical signs of abdominal disease. Routine blood testing showed anemia, presumably owing to occult bleeding. Ultrasonographic abdominal screening revealed ileo-ileal intussusception with a central hyperechoic tumor suggestive of a lipoma as lead point. This diagnosis was confirmed at surgery, where a small bowel resection was performed. Histologic examination disclosed a benign angiolipoma of the ileum with a superficial shallow ulceration which obviously was the source of the occult blood loss. Diagnostic and therapeutic procedures and a literature review are discussed.