Posterior dislocation of the sternoclavicular joint: report of two cases,with emphasis on radiologic management and early diagnosis

Posterior dislocations of the sternoclavicular joint are uncommon, but are potentially quite serious. Radiologic diagnosis and management are frequently difficult. The specialized projections available are not widely known, and the role of plain films is poorly understood. The incidence, pathomechanics, and clinical manifestations of such dislocations are presented and the radiologic diagnosis is discussed.     

VIM thalamic stimulation for tremor in a patient with IgM paraproteinaemic demyelinating neuropathy.

We demonstrate the effect of deep brain stimulation of the ventral intermediate thalamic nucleus on intractable action tremor, in a 72-year-old man suffering from neuropathy associated with monoclonal gammopathy.     

Nephron Sparing Surgery for De Novo Renal Cell Carcinoma in an Allograft Kidney: A Case Report

De novo renal cell carcinoma in a renal allograft is rare and has special implications in renal transplant recipients. We describe a patient with a renal allograft who developed a de novo renal cell carcinoma in the functioning renal allograft 258 months after transplantation. The patient underwent enucleation of the tumor because preoperative MRI showed it was well-encapsulated. A DNA banding study showed that the tumor originated from the donor. Indications for conservative renal surgery in renal cell carcinoma have been increasing. Accordingly, 1 option in the treatment of de novo renal cell carcinoma in a functioning renal allograft is enucleation as a method of nephron sparing surgery.     

Improved long-term bone-implant integration Experiments in transgenic mice overexpressing bovine growth hormone

Several recent studies have investigated the effects of growth hormone (GH) on the healing of fractures and bone ingrowth, but with conflicting results. The negative results may be due to antibody formation against injected GH or because some experimental models are able to prove only positive GH effects. In this study, we wanted to investigate the effect of GH on implant integration in bone. To avoid potential formation of antibodies against injected GH, we used a model with transgenic mice overexpressing bovine GH (bGH).

Titanium implants were inserted in the forehead of the mice. 4 months after insertion, the implants were cut out en bloc with the surrounding bone. The calcified specimens were cut and ground to a thickness of approximately 10m. Histomorphometry demonstrated significantly more direct bone-to-metal contact in the transgenic mice than in the nontransgenic littermates. Our findings indicate that systemic administration of GH in humans may improve implant integration in bone.     

Myocardial perfusion imaging: clinical experience and recent progress in radionuclide scintigraphy and magnetic resonance imaging

In the past 20 years, radionuclide scintigraphy has proven to be a sensitive clinical tool in the assessment of myocardial perfusion abnormalities. Magnetic resonance imaging may also be used to study myocardial perfusion, but its potential value still has to emerge in the clinical setting. This review addresses the potential and achievements of both methods in clinical cardiology.     

Adenoid cystic carcinoma: DNA as a prognostic indicator

A retrospective study was performed on 20 patients with adenoid cystic carcinomas of major salivary glands to see if DNA. patterns correlated with their prognoses. Fourteen tumors were found to be DNA. diploid; 6 were DNA aneuploid. Histologically, all DNA-aneu-ploid tumors had solid components, compared with only 5 of the DNA-diploid tumors. All of the DNA-aneuploid tumors recurred, in contrast to only 2 of the DNA-diploid tumors; the difference was highly significant (P<0.001). All of the patients with no recurrences had DNA-diploid tumors. In our study, DNA measurements of adenoid cystic carcinomas gave statistically significant information about prognosis and correlated to histological grading. We propose that evaluation of DNA content may be performed before planning the treatment of adenoid cystic carcinomas.     

Detection of local recurrence of soft-tissue sarcoma with positron emission tomography using [18F]fluorodeoxyglucose

Background: It is often difficult to detect a local recurrence of soft-tissue sarcomas due to disturbance of the normal anatomy by previous surgery and radiotherapy. The aim of this study was to assess the value of positron emission tomography (PET) with [¹⁸F]fluoro-2-deoxy-d-glucose (FDG) for detecting local recurrences. Methods: In the period 1992–1995, 17 patients with proven or suspected local recurrence of soft-tissue sarcoma were examined using FDG-PET. Fifteen of these patients were ultimately proven to have a recurrence. Results: Recurrence was visualized in 14 patients (93%). Small tumors (maximum diameter 0.5 cm) were as easily visible as large lesions (maximum diameter 20 cm). In one patient the PET scan was positive, but the recurrence could not be proven histologically. Recurrence was proven 1 year later. A recurrent low-grade liposarcoma was not visualized. The two patients with benign lesions had a negative PET scan. The mean glucose metabolic rate was calculated to be 13.2 μmol/100 g/min (range 1.9–28.4). A correlation was found between the histological malignancy grade and the metabolic rate (p<0.05; Kruskal-Wallis). Conclusion: PET with FDG is a useful addition to the diagnostic armamentarium for detecting local recurrence of soft-tissue sarcomas and provides an indication of the malignancy grade of the recurrent lesion. Presented at the 47th Annual Meeting of The Society for Surgical Oncology, Houston, Texas, March 17–20, 1994.     

Coronary vasomotion in patients with syndrome X: evaluation with positron emission tomography and parametric myocardial perfusion imaging

The aim of this study was to elucidate further the causative mechanism of abnormal coronary vasomotion in patients with syndrome X. In patients with syndrome X, defined as angina pectoris and documented myocardial ischaemia during stress testing with normal findings at coronary angiography, abnormal coronary vasomotion of either the micro- or the macrocirculation has been suggested as the causative mechanism. Accordingly, we evaluated endothelial function, vasodilator reserve, and perfusion heterogeneity in these patients. Twenty-five patients with syndrome X (definitely normal coronary arteriogram, group A), 15 patients with minimal coronary artery disease (group B) and 21 healthy volunteers underwent [¹³N]ammonia positron emission tomography at rest, during cold pressor stimulation (endothelial function) and during dipyridamole stress testing (vasodilator reserve). Heterogeneity of myocardial perfusion was analysed by parametric polar mapping using a 480-segment model. In both patient groups, resting perfusion was increased compared to the normal subjects: group A, 127±31 ml·min^–1·100 g^–1; group B, 124±30 ml·min^–1·100 g^–1 normal subjects, 105±21 ml·min^–1·100 g^–1 (groups A and B vs normals,P<0.05). These differences were abolished after correction for rate-pressure product. During cold pressor stimulation, the perfusion responses (ratio of cold pressor perfusion to resting perfusion) were similar among the patients and the control subjects (group A, 1.20±0.23; group B, 1.24±0.22; normal subjects, 1.23±0.14). Likewise, during dipyridamole stress testing, perfusion responses were similar among the three groups (group A, 2.71±0.67; group B, 2.77±1.29; normal subjects, 2.91±1.04). In group A the heterogeneity of resting perfusion, expressed as coefficient of variation, was significantly different from the volunteers (20.1±4.5 vs 17.0±3.0,P<0.05). In group B (coefficient of variation 19.4±3.9) the difference from normal volunteers was not significant. In this study, patients with syndrome X and patients with minimal coronary artery disease showed normal perfusion responses during cold pressor stimulation and dipyridamole stress testing. Our findings therefore suggest that endothelial dysfunction and impaired vasodilator reserve are of no major pathophysiological relevance in patients with syndrome X. Rather, other mechanisms such as increased sympathetic tone and focal release of vasoactive substances may play a role in the pathogenesis of syndrome X.     

Differential effects of luminol,nickel, and arsenite on the rejoining of ultraviolet light and alkylation-induced DNA breaks

When Chinese hamster ovary cells were treated with ultraviolet (UV) light or methyl methanesulfonate (MMS), a large number of DNA strand breaks could be detected by alkaline elution. These strand breaks gradually disappeared if the treated cells were allowed to recover in a drug-free medium. The presence of nickel or arsenite during the recovery incubation retarded the disappearance of UV-induced strand breaks, whereas the disappearance of MMS-induced strand breaks was retarded by the presence of arsenite or of luminol, a new inhibitor for poly(ADP-ribose) synthetase. Luminol, however, had no apparent effect on the repair of UV-induced DNA strand breaks, and nickel had no effect on the repair of MMS-induced DNA strand breaks. When UV- or MMS-treated cells were incubated in cytosine arabinofuranoside (AraC) plus hydroxyurea (HU), a large amount of low molecular weight DNA was detected by alkaline sucrose sedimentation. The molecular weight of these DNAs increased if the cells were further incubated in a drug-free medium. This rejoining of breaks in cells pretreated with UV plus AraC and HU was inhibited by nickel and by arsenite, but not by luminol. The rejoining of breaks in cells pretreated with MMS plus AraC and HU was inhibited by luminol and by arsenite, but not by nickel. These results suggest that different enzymes may be used in DNA resynthesis and/or ligation during the repairing of UV- and MMS-induced DNA strand breaks, and that nickel, luminol, and arsenite may have differential inhibitory effects on these enzymes. © 1994 Wiley-Liss, Inc.     

Effect of ethanol on ascorbate release in the nucleus accumbens and striatum of freely moving rats.

An in vivo voltammetry technique was used to monitor the extracellular ascorbate (AA) concentration in the nucleus accumbens and striatum of unanesthetized, freely moving rats. A single injection of ethanol, 1.0 g/kg intraperitoneally (IP), induced a significant increase in extracellular AA concentration in both the nucleus accumbens and striatum. This effect was dose dependent within a dose range from 0.5-2.0 g/kg. 4-Methylpyrazole (50 mg/kg, IP), which inhibits alcoholdehydrogenase, could not prevent the increase in AA concentration, evoked by ethanol. Furthermore, systemic administration of acetaldehyde (20 mg/kg, IP), the main metabolite of ethanol, did not have any effect on the level of AA in the nucleus accumbens or striatum. These results show that ethanol can alter the brain extracellular AA levels and that this effect seems to be attributed to ethanol itself and not to acetaldehyde. Consequently, these results indicate that a role for AA in the action of ethanol in the brain should be considered.