Macular translocation: unifying concepts, terminology, and classification

PURPOSE: To describe some unifying concepts, terminology, and classification of macular translocation so as to facilitate communication within the scientific community. METHODS: A panel of ophthalmologists with expertise in macular translocation reviewed available data and developed some unifying concepts, terminology, and classification of macular translocation. RESULTS: Macular translocation may be defined as any surgery that has a primary goal of relocating the central neurosensory retina or fovea intraoperatively or postoperatively specifically for the management of macular disease. It may be classified according to the size of the retinotomy and, where applicable, the technique of chorioscleral shortening used. The direction of macular translocation is denoted by the movement of the neurosensory macula relative to the underlying tissues. Effective macular translocation may be defined as successful intraoperative or postoperative relocation of the fovea overlying a subfoveal lesion to an area outside the border of the lesion. The concepts of minimum desired translocation and median postoperative foveal displacement can give some useful idea of the likelihood of effective macular translocation before surgery. CONCLUSIONS: Use of a common standardized terminology for macular translocation will facilitate communication within the scientific community and enhance further research in this area. However, the definitions, terms, classification, and concepts concerning macular translocation are likely to continue to evolve as macular translocation undergoes further modifications and refinements.     

Cervical intramedullar schistosomiasis as a rare cause of acute tetraparesis

INTRODUCTION: The trematode infection schistosomiasis affects at least 200 million people in endemic areas. Granulomas cause the typical manifestations of urogenital, intestinal and hepatolienal schistosomiasis. Involvement of other organs especially the central nervous system (CNS) is uncommon. CASE REPORT: We describe a 40-year old male with a history of repeated contact with schistosome contaminated water. After having suffered from flu-like symptoms with fever and arthralgias, he first presented with a polyradiculopathy of unknown origin. Then 4 weeks later an acute tetraparesis occurred. Spinal magnetic resonance imaging (MRI) revealed a spinal stenosis and query medullary hyperintensities at C6-C8 without contrast-enhancement. Serologic testing was positive for schistosomiasis. The intraoperative appearance at decompressive laminectomy revealed a myelitic form of schistosomiasis. Under therapy with praziquantel, initially high dose cortisone and intensive physiotherapy, symptoms slowly improved over months. On follow-up 1 year later, the patient presented with a spastic distally marked tetraparesis and sensory impairment from C6 downwards. CONCLUSION: Cervical intramedullar schistosomiasis is a rare cause of acute tetra- or para-paresis in patients, who have had contact with schistosomes. Early diagnosis is essential because of the excellent prognosis with specific therapy.     

Arthroscopic therapy in limited mobility of the elbow joint

Limitation of elbow mobility constitutes a grave problem for therapy. Arthroscopy offers a therapeutic option, but in cases of loss of motion poses a considerable challenge to the operative technique. Placement of the portals already carries an increased risk of neurovascular lesions due to the altered anatomy and reduced distension capacity of the joint. Thus, particular significance attaches to the standardized arthroscopic procedure for localization and placement of the cannulas, intra-articular assessment, differentiated evaluation of the dorsal joint regions, and operative tactics for transsection of cicatrization, removal of loose bodies, and excision of osteophytes. If extra-articular factors are involved in the genesis of the limited motion, arthroscopic treatment often does not achieve the desired result. It is therefore considered propitious to differentiate the causes of the loss of motion during clinical examination with imaging diagnostics, in particular to determine those caused by extra-articular elements. If, however, individually localized intra-articular adhesive bands or loose bodies are responsible, the prognosis for arthroscopic management is clearly more favorable. Patients with minor loss of motion (> 15 degrees) profit more from the arthroscopic operation than those with a extension or flexion deficit of more than 30 degrees.     

Continuous measurements of renal perfusion in pigs by means of intravascular Doppler

BACKGROUND: Changes in renal blood flow are considered to play a significant role in the induction and maintenance of kidney failure, but are difficult to monitor with currently available techniques. The objective was to validate renal flow measurements with Doppler guidewires and to apply this technique to assess dose and time dependency of the renal vascular effects of norepinephrine (NE). METHODS: In 10 anesthetized pigs, flow velocity in renal arteries (FVart) and veins (FVvein) and volumetric renal blood flow (VBF) were measured before and after intravenous bolus application of incremental doses of NE (2 to 200 microg). RESULTS: FVart curves exactly reflected the changes in VBF. Beat-to-beat analysis revealed a strong linear correlation over a mean VBF range of less than 0.05 to 0.35 L/min (median correlation coefficient with FVart, r = 0.998), and significant but less close relationships were also found between VBF and FVvein. Ten seconds after the administration of 200 microg NE, FVart dropped from 71 to 6 cm/sec and was 90% reversible after 48 seconds. Similarly, the renal vascular resistance temporarily rose from 988 to 13711 mm Hg. min/L. In contrast, NE-induced increases in systemic vascular resistance were on average a maximum of 1.5-fold but persisted for more than 60 seconds. CONCLUSIONS: Doppler flow measurements in the renal artery provide an excellent surrogate of volumetric blood flow, which may be useful for continuous monitoring of renal hemodynamics. The renal vasculature is more sensitive when compared with the systemic vasculature, but also appears to evoke more efficient counter-regulatory mechanisms in response to NE.     

Simultaneous in utero assessment of AV nodal and ventricular electrophysiologic parameters in the fetal sheep heart

Background Fetal tachyarrhythmias are usually of supraventricular origin. To investigate whether specific electrophysiologic properties of the fetal heart contribute to this preponderance by either favoring supraventricular tachycardias or by rendering ventricular tachycardias unlikely, we measured fetal electrophysiologic parameters in utero using transuterine fetal transesophageal electrocardiograms in fetal sheep. Since overdrive pacing may help to establish the mechanism of an arrhythmia and may be used to treat fetal tachycardias, different modes of transesophageal pacing in utero were also assessed. Methods and results Decapolar electrophysiology catheters were fetoscopically inserted into the esophagus of 9 fetal sheep (pregnancy duration 94 – 105 days, term = 145 days). Electrocardiograms were recorded simultaneously from all adjacent bipoles and from two pacing wires sutured onto the fetal shoulders. Pacing was attempted either via two adjacent electrodes of the intraesophageal catheter or via the most distal and most proximal electrode. Fetal cycle length, PQ, and QT intervals were close to (approx. 75 %), but fetal QRS duration was < 20 % of maternal values, thus shifting the relation between activation and repolarization towards longer excitation wave lengths. Fetal QT dispersion was small (≤ 10 ms). Atrial pacing was achieved in all fetuses using distant electrodes, and with lower thresholds when compared to closely spaced bipolar electrodes (p < 0.05). Conclusions (I) An altered relation between ventricular activation and repolarization and a low dispersion of ventricular repolarization may protect the fetal heart against ventricular reentrant tachycardias. (II) Relatively normal fetal AV nodal conduction delay already provides one of the prerequisites for supraventricular reentrant tachycardias involving the AV node at this stage of fetal development. (III) High-rate esophageal pacing of the fetal atria is best achieved using widely spaced bipolar pacing electrodes. Received: 26 July 2000, Returned for 1. revision: 16 August 2000, 1. Revision received: 28 November 2000, Returned for 2. revision: 18 December 2000, 2. Revision received: 23 January 2001, Accepted: 24 January 2001     

Event-related perturbations in an electrophysiological measure of auditory function: a measure of sensitivity during orienting?

The effects of salient foreground stimuli in evoked potentials to weak background probe stimuli were examined in situations requiring passive observation or discriminative judgments of foreground tone stimuli. The background probe stimuli consisted of a continual train of weak acoustic stimuli presented at a rate of about 40 stimuli per second. Under such conditions, a 40-Hz steady-state rhythm (SSR) is established, which has been proposed to consist of the algebraic summation of individual middle-latency components evoked by stimuli in the train. The 40-Hz SSR was averaged over trials and extracted from the composite event-related potential signal using narrow-band digital filtering, for continuous examination of latency and amplitude during the course of the period immediately preceding and following the foreground stimulus. The foreground stimulus was followed by a brief period (peaking at about 200 ms) during which the latency of response to the background probe stimuli was reduced. The extent of this latency reduction was in proportion to the magnitude of the simultaneous slow-wave ERP responses and, to a lesser extent, heart rate responses. It is proposed that the results may reflect a transient period of sensitization during orienting, at a presumably early level in the auditory system, and that the method thus offers a means for determining the extent and temporal course of such effects.     

Further evidence for a functional role of the glutamate receptor gene GRM3 in schizophrenia

In recent years, evidence has been accumulating indicating a major role of glutamate in the pathogenesis and pathophysiology of schizophrenia. Of particular importance in this regard are the metabotropic glutamate receptors (GRM). Thus, a recently published trial of the amino acid analogue LY2140023, which exerts its effects through the activation of the glutamate receptors GRM3/GRM2, showed an improvement of positive and negative symptoms comparable to treatment with olanzapine. A functional variant of GRM3 has been described which modulates synaptic glutamate levels. We assessed whether this functional variant rs6465084 is related to schizophrenia in a large sample of patients and controls. We found an increased frequency of the A allele (p=0.027) and the AA genotype (p=0.024) in schizophrenia patients. Moreover, in an assessment of schizophrenia endophenotypes, patients of the AA genotype performed poorly in the digit symbol test, a measure of attention (p=0.008). Our results provide further evidence for the potential importance of the glutamate receptor GRM3 in schizophrenia, and indicate that the novel antipsychotic LY2140023 may actually be targeting a pathogenic pathway of schizophrenia.     

Hyperbare Sauerstofftherapie

The aim of hyperbaric oxygenation (HBO) is to increase transported oxygen in the blood over the rise of the physiologically solved part. In oral and maxillofacial surgery, treatment-resistant osteomyelitis and osteoradionecrosis are indications for HBO (according to Undersea and Hyperbaric Medical Society). Furthermore, there is an indication to apply HBO to compromised transplants of bone or soft tissue. Since 1994, 28 patients have been treated with HBO in the department of oro-, maxillofacial surgery of the Medical School Hannover. Sixteen patients had a treatment-resistant osteomyelitis. Two patients were suffering from an osteoradionecrosis in the irradiated mandible. Nine patients had received autogenous transplants, which were threatened by infection or an insufficient recipient-side. One patient was treated because of a chronic non-healing wound. In six patients we found that the chronic osteomyelitis had healed. This was proven by clinical examination and scintigraphic findings. In eight patients we had a decrease in turnover in scintigraphy and an improvement of the clinical situation. Two patients with osteoradionecrosis showed clinical improvement under HBO. In nine patients with threatened transplants we saw good healing of all critical grafts under HBO. One patient with a non-healing wound could be cured with HBO. It was shown that with HBO we could cure osteomyelitis, osteoradionecrosis and non-healing wounds to a large extent. Grafts which were threatened by infection or insufficient recipient-side healed after the application of HBO.