Frontal lobe in vivo (31)P-MRS reveals gender differences in healthy controls, not in schizophrenics

Phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) has gained much interest in schizophrenia research in recent years since it allows the non-invasive measurement of high-energy phosphates and phospholipids in vivo. However, until now only differences in metabolite concentrations between certain brain areas of schizophrenic patients and healthy controls have been examined. We investigated the influence of gender on the concentrations of different phosphorus compounds. For this purpose, well-defined volumes in the frontal lobe of 32 healthy controls and 51 schizophrenic in-patients were examined with an image selected in vivo spectroscopy (ISIS) sequence on a whole-body scanner at 1.5 T. Healthy females exhibited increased values of inorganic phosphate (P(i)) and decreased values of phosphocreatine (PCr) in comparison to their male counterparts. In schizophrenic patients such gender differences were not present. Thus, the results can be interpreted in the sense that frontal energy demanding processes are enhanced in female compared to male healthy volunteers; schizophrenia seems to reduce these gender differences.     

Gabapentin leads to remission of somatoform pain disorder with major depression

Gabapentin, a novel antiepileptic drug, is effective in the treatment of partial seizures with and without secondary generalization. Evidence suggests that it may have mood-stabilizing and possibly antidepressant properties in bipolar depression. We report on a 48-year-old woman who had recurrent major depressive disorder. Following inguinal herniorrhaphy, she developed severe stabbing pain in the lower abdomen and inguinal area that progressed to constant pain in her whole body. She was depressive, hopeless, and had given up her social activities. A diagnosis of major depressive disorder and somatoform pain disorder was made. Antidepressants and carbamazepine were ineffective, and she had attempted suicide. Gabapentin resulted in remission of both the pain and the depressive mood at a dose of 1.800 mg/day.     

The role of fixation and bone quality on the mechanical stability of tibial knee components

Tibial component loosening remains one of the major causes of failure of cemented and noncemented total knee arthroplasties. In this study, the authors identified the role of implant design, method of fixation, and bone density as it related to implant stability. The physical properties of "good" and "bad" bone were simulated using a "good" and "bad" foam model of the proximal tibia, fabricated in the laboratory from DARO RF-100 foam. A generic tibial component permitting various fixation designs was implanted into "good" and "bad" variable density foam tibial models in both cemented and noncemented modes. The mechanical stability of the implants was determined using a Materials Testing Machine by the application of an eccentrically applied cyclic load. The micromotion (subsidence and lift-off) of the tibial implants was recorded using two Linear Variable Differential Transformers. Statistically significant differences in implant stability were recorded as a function of fixation method. The most rigid implant fixation was achieved using four peripherally placed, 6.5-mm cancellous screws. The addition of a central stem added stability only in the case of "poor" quality foam. The mechanical stability of noncemented implants related directly to the density of the foam. Implant stability was greatly enhanced in "poor" quality foam by the use of cement. The method of implant fixation and bone density are critical determinants to tibial implant stability.     

Ein vollständig implantierbares Hörsystem für Innenohrschwerhörige: TICA LZ 3001

Zusammenfassung Kürzlich wurde über die Entwicklung eines elektromechanischen, piezoelektrischen Wandlers und eines Mikrofons zum subkutanen Einbau in die hintere Geh?rgangswand als Komponenten eines zukünftigen vollst?ndig implantierbaren H?rsystems für Innenohrschwerh?rige berichtet (HNO 45, 1997, 792–880). Zwischenzeitlich konnte die Entwicklung eines elektronischen Hauptmoduls zur Implantation auf dem Planum mastoideum abgeschlossen werden, das diese Mikrofone und Wandler zu dem kompletten H?rimplantat TICA? LZ 3001 erg?nzt. Dieses Hauptmodul enth?lt neben der signalverarbeitenden Elektronik eine spezielle Batterie, die transkutan mit einem portablen Ladeger?t nachgeladen wird. Nach einer Volladung, die ca. 2 h ben?tigt, ist das Implantat für rund 50 h kontinuierlich betriebsbereit. Das Ladeger?t wird ?hnlich wie bei Mobiltelefonen in einer netzbetriebenen Station nachgeladen. L?sbare Steckverbindungen zu Mikrofon und Wandler erm?glichen den einfachen operativen Austausch des Hauptmoduls, wenn die Batterielebensdauer erreicht ist. Dies wird nach ca. 3–5 Jahren erwartet. Dem Patienten steht eine kleine, drahtlose Fernbedienung zur Verfügung, mit der Lautst?rke, Ein/Aus sowie 4 H?rprogramme für unterschiedliche H?rsituationen eingestellt werden k?nnen. Die grundlegenden audiologischen Eigenschaften sind durch ein flexibel digital programmierbares 3-Kanal-AGC-System mit Peak-clipping-Funktion gegeben. Die gesamte übertragungsbandbreite betr?gt ca. 10 kHz. Das vollimplantierbare H?rsystem wurde im Rahmen der klinischen Erprobung Anfang Juni 1998 erstmals am Menschen angewendet.