[Definition of prostatic contours using tomodensitometric slices: study of differences among radiotherapists and between examinations]. / Définition des contours prostatiques sur coupes tomodensitométriques: étude des discordances entre radiothérapeutes et entre examens.

Accuracy of conformal treatment planning for prostatic radiotherapy is based on the contours of target volumes (prostate +/- seminal vesicles) and normal tissues (rectum and bladder), drawn on CT (computed tomography) images by radiation oncologists. The interpretation of a given CT image can be different from one radiation oncologist to another, and may change in time with the state of filling of the bladder and of the rectum during the treatment. In order to quantify these variations, 12 patients treated with conformal radiotherapy for prostate carcinoma (pelvis 40 Gy/20 sessions + prostate 30 Gy/15 sessions) had two series of CT at one month intervals. Contouring of prostate, rectum and bladder were performed independently on each CT by two radiation oncologists. The first CT scan (planning CT) and the first series of contours (planning contours) were used for treatment planning. The contours of the second scan were compared to the planning contours after image fusion based on manual superimposition of bony anatomy of the two sets of CT images. Coherence ratio were defined to measure discrepancies in prostate volumes between radiation oncologists (RCE) and between scans (RCT). The mean RCE was 38 +/- 7% (1 standard deviation). Those discrepancies were primarily located at the prostate apex and at the interface between bladder and prostate and between rectum and prostate. The mean RCT was 42 +/- 8% (1 sigma). Those discrepancies were due to the prostate motion related to the state of filling of the rectum and bladder. For bladder and rectal walls, less important differences were observed between the two radiation oncologists for the same CT (4.5% for rectal volume receiving 65 Gy or more, 3% for bladder volume receiving 65 Gy or more). However, important differences in bladder and rectal volumes receiving 65 Gy or more (16% and 7% respectively) were noted for the same patient from a CT to another due to the variation in bladder or rectal filling. New techniques for planning CT acquisition are needed to decrease the discrepancies due to contouring. The treatment must, as far as possible, be delivered with an empty bladder and rectum in order to ensure a good reproduction of the initially planned treatment.

[Conformational radiotherapy in cancers of the prostate: contribution of pelvic immobilization and new fiducial markers]. / Radiothérapie conformationnelle des cancers de la prostate: apport de la contention pelvienne et de nouveaux repères de positionnement.

PURPOSE: To reduce errors in the positioning of patients treated with external conformal radiotherapy for prostate cancer, we evaluated both the use of an immobilization device and new fiducial markers. MATERIALS AND METHODS: The immobilization device consisted of an individual mold made of polyurethan foam. Two sets of skin markers located on the anterior tibial surfaces were used to identify the pelvic isocenter. The patient's position was evaluated by orthogonal port films which were then compared with the original simulation film. RESULTS: Results are presented with respect to orthogonal axes. Comparison with classic procedures without immobilization showed that use of the mold and new fiducial markers led to a decrease in set-up errors which were less than 5 mm. CONCLUSION: With the use of an immobilization device and optimized techniques for patients' positioning, conformal radiotherapy of prostate cancer is more accurate.

Conservative treatment of bilateral sural nerve entrapment in an ice hockey player.

Midway through the season, an intercollegiate ice hockey player experienced bilateral numbness in the posterior aspect of the leg along the area of the calcaneal tendon. This numbness corresponded with the distribution of both sural nerves. While obtaining a history of the condition, the athlete admitted that he routinely spiraled his ice hockey laces tightly around the proximal portion of each ice hockey boot before finally tying the laces off. A complete neurological examination was negative except for the bilateral numbness. Based upon this information, a diagnosis of bilateral sural nerve entrapment was made. In addition to frequent follow-up examinations, nonoperative treatment consisted of changing the way the athlete laced his ice hockey skates. The athlete was able to complete the season and, after approximately 4 months, was asymptomatic. Although this appears to be an isolated incident, athletic trainers should be cautious when evaluating patients with paraesthesia in this region. If symptoms such as those described develop, entrapment of the sural nerve should be considered as a possible cause.

Arterial supply to the human anterior cruciate ligament.

The arterial supply to the anterior cruciate ligament (ACL) was prepared for study by injecting a fresh cadaver knee with an epoxy lead-oxide solution and subsequently immersing it in 10% formalin for a 2-week period. The vasculature of the ACL was exposed through dissection for examination. A second specimen was prepared similarly and was evaluated by a CAT scan. ACL vascularization arises from the middle genicular artery and vessels of the infrapatella fat pad and adjacent synovium. The artery gives rise to periligamentous vessels which form a web-like network within the synovial membrane. These periligamentous vessels give rise to penetrating branches which transversely cross the ACL and anastomose with a network of longitudinally oriented endoligamentous vessels. Terminal branches of the inferior medial and lateral genicular arteries supply the distal portion of the ACL directly. The extremities of the ACL seem to be better vascularized than the middle part, and the proximal portion seems to have a greater vascular density than the distal portion. The arteries at the ligamentous-osseous junctions of the ACL do not significantly contribute to the ligament's vascularity. Ramifications concerning the ACL's blood supply as it relates to athletic training is also discussed.

Selective depletion of tumor ATP by 2-deoxyglucose and insulin, detected by 31P magnetic resonance spectroscopy.

The purpose of this study was to investigate whether substrate deprivation acutely and selectively decreases ATP concentration in an experimental sarcoma. Two methods of substrate deprivation were examined: glycolysis was inhibited using 2-deoxyglucose (2DG), and plasma substrate levels were reduced using insulin. The effects of treatment on tumor ATP, inorganic phosphate, and pH were studied by 31P nuclear magnetic resonance spectroscopy. 2DG (2 g/kg) was administered i.p. to rats bearing s.c. methylcholanthrene-induced sarcomas. Inhibition of glycolysis by 2DG caused a 52 +/- 13% (SE) decrease in the tumor ATP to inorganic phosphate ratio, associated with a decrease in pH of 0.38 +/- 0.10 unit. The same dose of 2DG caused no significant change in the ratio of phosphocreatine to ATP in brain. Insulin (125 units/kg, i.p.) caused a 68% decline in plasma glucose and a 71% decline in betahydroxybutyrate compared to saline-treated animals. Concomitantly, 31P nuclear magnetic resonance spectroscopy detected a 48 +/- 13% decrease in sarcoma ATP, with a reciprocal elevation of inorganic phosphate in insulin-treated animals. In contrast, the brain phosphocratine/ATP ratio was unaffected by insulin. These results suggest that large tumors are acutely sensitive to inhibition of glycolysis and reductions in plasma levels of substrates for oxidative phosphorylation and glycolysis, while the brain is unaffected. In addition, this work provides support for the use of 31P nuclear magnetic resonance spectroscopy to monitor tumor response to therapy.

The incidence of hyponatremia in prolonged exercise activity.

Hyponatremia is a medical condition characterized by decreased concentration of sodium in the blood, which may occur in participants in endurance and ultraendurance athletic events. Slower competitors and nonacclimatized individuals appear to be at greater risk of becoming hyponatremic, especially if they experience salt depletion as a result of sweating or water intoxication. Clinical signs and symptoms of hyponatremia, which can range from muscle cramps and mental confusion to convulsions and coma, may not manifest themselves until well after the end of the event. Death may occur if hyponatremia is not properly diagnosed and treated. Medical personnel treating this condition should be cautious not to confuse water intoxication with dehydration, which produces similar symptoms. To prevent hyponatremia, participants should acclimatize themselves to race conditions prior to the event. In addition, endurance athletes should be encouraged to ingest low sodium concentrate drinks during events lasting longer than 4 hours.

Fractures to the Fifth Metatarsal.

In brief Two intercollegiate hockey players sustained a fracture of the fifth metatarsal. They were treated conservatively with a short leg cast for 10 to 13 days, followed by 4 to 6 weeks of physical therapy and no weight bearing. The athletes returned to competition 12 and 18 days postinjury, respectively. An Orthoplast pad was attached to the outside of the skate to protect the area during competition. Both players finished the season with no further problems. Because hockey players do not experience lower-extremity pounding, they can return to participation quickly and safely after fractures to the fifth metatarsal bone.

In vivo alterations of high-energy phosphates and intracellular pH during reversible ischemia in pigs: a 31P magnetic resonance spectroscopy study.

Phosphorus-31 magnetic resonance spectroscopy was used to study the relationship between metabolic and functional alterations during acute regional ischemia in vivo. Phosphocreatine, adenosine triphosphate (ATP), inorganic phosphate, and intracellular pH (pHi) were monitored in 11 pigs at 2-minute intervals during 4 and 20 minutes of acute left anterior descending coronary artery occlusion followed by 20 minutes of reperfusion. In a parallel series of experiments, segment shortening was continuously monitored by sonomicrometry during the early ischemic period. Segment shortening decreased precipitously after coronary occlusion, and systolic expansion was noted within 30 seconds. Phosphocreatine levels decreased rapidly and reached a minimum value of 44 +/- 13% (mean +/- SE) of the control value by 20 minutes of ischemia. Ischemia-induced reduction of ATP was small and not statistically significant. Inorganic phosphate increased rapidly to a peak level of 158 +/- 9% of the control value by 4 minutes of ischemia. Intracellular pH decreased 0.76 +/- 0.04 units during the initial 10 minutes of ischemia and subsequently stabilized. After reperfusion, phosphocreatine, inorganic phosphate, and pHi recovery occurred within 4 minutes and was similar in the 4- and 20- minute ischemia groups. These results indicate that the changes in high-energy phosphates and pHi observed during both 4 and 20 minutes of coronary occlusion are rapidly reversible. The temporal course of metabolic and functional alterations during early ischemia suggests that if these are causally related the decline in contractility is mediated by an increase in inorganic phosphate, a decrease in pHi, or both rather than by loss of ATP.

Inhibition of tumor high-energy phosphate metabolism by insulin combined with rhodamine 123.

The purpose of this study was to determine whether the energy metabolism of an experimental rodent sarcoma was selectively depressed by the combination of inhibition of glycolysis and respiration. In vivo phosphorus-31 nuclear magnetic resonance spectroscopy was used to monitor the response of tumor or brain high-energy phosphate compounds to insulin hypoglycemia, rhodamine 123, or both agents in fasting rats with subcutaneous methylcholanthrene-induced sarcomas. Insulin or rhodamine 123 alone produced a similar 50% to 60% reduction in tumor adenosine triphosphate (ATP) concentration compared with controls injected with saline solution (p less than 0.05, one-way analysis of variance [ANOVA]). The combination of insulin plus rhodamine 123 resulted in a 90% reduction of tumor ATP concentration, which was significantly different from the effect of either agent alone (p less than 0.05, one-way ANOVA). Brain phosphocreatine and ATP concentrations were unchanged by these agents. Administration of dimethyl sulfoxide (DMSO)/glycerol, the vehicle for rhodamine, produced a 35% reduction of tumor ATP, which was similar to the effect of insulin alone but significantly different from rhodamine. The combination of DMSO/glycerol plus insulin hypoglycemia resulted in a 70% reduction in tumor ATP, which was significantly elevated compared with the combination of rhodamine plus insulin. Glucose deprivation induced by insulin, and combined with the inhibition of oxidative phosphorylation, produces an additive depression of tumor energetics. The drug vehicle DMSO/glycerol significantly depresses tumor energy metabolism, presumably because of its DMSO component, which may explain the previously reported antineoplastic efficacy of this solvent. Combinations of inhibitors directed at different points of tumor metabolism produced an enhanced depression of tumor energetics, whereas host tissue was protected.