Rare diseases mimicking acute vertebrobasilar artery thrombosis

Acute ischaemia of the vertebrobasilar circulation leads to a variety of clinical manifestation and is mostly due to cardiogenic or artery-to-artery embolism. We describe four neurological emergency situations involving vertebrobasilar artery aclusion of other origins: basilar migraine, extrinsic compression by rheumatoid inflammatory tissue, generalized vasculitis in subacute rheumatic fever and basilar artery dissection. The differential diagnosis of acute vertebrobasilar artery occlusion may have an important impact on patient management.     

Regulation of COX-2 mediates acid-induced bone calcium efflux in vitro.

Chronic metabolic acidosis induces net Ca efflux from bone; this osteoclastic bone resorption is mediated by increased osteoblastic prostaglandin synthesis. Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, is present in both constitutive (COX-1) and inducible (COX-2) forms. We report here that acidosis increases both osteoblastic RNA and protein levels for COX-2 and that genetic deficiency or pharmacologic inhibition of COX-2 significantly reduces acid-induced Ca efflux from bone. INTRODUCTION: Incubation of neonatal mouse calvariae in medium simulating physiologic metabolic acidosis induces an increase in osteoblastic prostaglandin E2 (PGE2) release and net calcium (Ca) efflux from bone. Increased PGE2 is necessary for acid-induced bone resorption, because inhibition of cyclooxygenase activity with indomethacin significantly decreases not only PGE2 production but also Ca release. Cyclooxygenase is present in both constitutive (COX-1) and inducible (COX-2) forms. Because COX-2 activity has been implicated in several forms of pathological bone resorption, we tested the hypothesis that COX-2 is critical for acid-induced, cell-mediated bone Ca efflux. MATERIALS AND METHODS: To determine the effect of metabolic acidosis on COX-2 RNA and protein, primary cells isolated from neonatal CD-1 mouse calvariae were cultured in neutral (Ntl) or physiologically acidic medium (Met). RNA levels for COX-2 and COX-1 were measured by quantitative real-time PCR. Levels of COX-2 and COX-1 protein were measured by immunoblot analysis. To determine the effect of acidosis on bone Ca efflux in genetically deficient COX-2 mice, mice heterozygous for the COX-2 knockout (strain B6;129S7-Ptgs2(tm1Jed)/J) were used as breeders, and neonatal calvariae were cultured in Ntl or Met. To determine the effects of the specific COX-2 inhibitor, NS398, on acid-induced bone resorption, CD-1 calvariae were incubated in Ntl or Met with or without NS398 (1 microM). Medium PGE2 was assayed by ELISA. RESULTS: Incubation of mouse calvarial cells in Met significantly increased COX-2 RNA and protein levels without a change in COX-1. Increased COX-2 protein levels in response to Met were also observed in cultured calvariae. Acid-induced, cell-mediated Ca efflux from B6;129S7-Ptgs2(tm1Jed)/J calvariae was dependent on genotype. From 0 to 24 h, when physicochemical Ca efflux predominates, Met significantly increased net Ca efflux in all genotypes. After 24 h, when cell-mediated Ca efflux predominates, Met induced greater Ca efflux from (+/+) than from (+/-), and there was no increase from (-/-). In calvariae from CD-1 mice, NS398 significantly inhibited both the acid-induced increase in PGE2 and Ca release. CONCLUSIONS: The specific acid-induced increase in COX-2 RNA and protein levels and the dependency of the increased Ca efflux on COX-2 activity, as determined by both genetic deficiency and pharmacologic inhibition, show that COX-2 is critical for acid-induced, cell-mediated bone resorption.     

Superiority of the University of Wisconsin solution over simple crystalloid for extended heart preservation. A study of left ventricular pressure-volume relationship.

To compare the effects of the University of Wisconsin solution with those of an extracellular crystalloid solution, Krebs-Ringer bicarbonate, as cardiac preservation media, we studied 35 adult dogs in an isolated heart preparation. Four groups of seven hearts were preserved in University of Wisconsin solution for 6 or 12 hours or in Krebs-Ringer bicarbonate solution for 6 or 12 hours. An additional group of seven hearts with no ischemia was used for a control group. In the four preservation groups, hearts were arrested by electrolyte solution (Normosol with potassium chloride, 20 mEq/L, added, 4 degrees C), flushed with 200 ml of the preservation solution, and then stored in the same solution at 1 degree to 2 degrees C. The hearts were mounted on an isolated heart preparation equipped with a computer-controlled servo-pump system that used a mock arterial system to modulate the aortic input impedance presented to the left ventricle. Left ventricular pressure-volume loops were measured on-line for 2 hours of reperfusion with autologous warm oxygenated blood. Elastance was derived from the end-systolic pressure-volume relationship, and diastolic compliance was derived from the end-diastolic pressure-volume relationship. The total left ventricular performance was assessed by the preload recruitable stroke work area, the slope, and its x-intercept, all of which derived from the stroke work (pressure-volume area)-end-diastolic volume relationship. Extended global ischemia had more deleterious effects on the end-diastolic than the end-systolic pressure-volume relationship. In confirmation with other studies, elastance did not accurately reflect the level of ventricular contractile dysfunction because of the significant amount of diastolic dysfunction. The preservation of myocardial systolic and diastolic functions, as demonstrated by the preload recruitable stroke work area and diastolic compliance, was better in the University of Wisconsin solution groups than in the Krebs-Ringer bicarbonate solution groups after 6 and 12 hours of preservation. In addition, 6 hours of preservation with University of Wisconsin solution maintained normal systolic and diastolic functions as compared with those of the control group. Preservation with University of Wisconsin solution prevented any myocardial edema formation; by contrast, this was significantly increased after 12 hours in Krebs-Ringer bicarbonate solution. Groups preserved with University of Wisconsin solution had less reperfusion injury as evidenced by the release of coronary sinus creatine kinase during reperfusion; they also had improved oxygen use during reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)     

Pharmacological priapism: Comparison of trazodone- and papaverine-associated cases

Priapism occurred in ten patients undergoing treatment of depression with trazodone or impotence with papaverine. Trazodone-related priapism uniformly required surgical procedures and resulted in impotence in two of three cases. In contrast, papaverine-associated priapism was successfully managed by aspiration and all seven patients continued to respond to intracorporal treatment. Iatrogenic priapism is an important complication of therapy with vasoactive drugs.     

Monitoring of somatosensory evoked potentials during surgical procedures on the thoracoabdominal aorta. III. Intraoperative identification of vessels critical to spinal cord blood supply

Somatosensory evoked potentials were used to locate intercostal arteries critical to spinal cord blood flow in nine dogs. To mimic a clinical situation, the proximal descending thoracic aorta (left subclavian artery to T7) was excluded with cross-clamps, and partial pulsatile left atrial-femoral artery bypass was instituted to maintain distal aortic pressure at 100 mm Hg. Progressively lower aortic segments were excluded (T7-10, T10-L1, L1-3, L3-6, L6-7) until loss of somatosensory evolved potentials occurred. Spinal cord blood flow measurements at the time of evoked potential loss revealed significant ischemia (p less than 0.02 versus baseline) in the excluded segment in seven animals but normal spinal cord blood flow in the remainder of the cord. Upon reperfusion, significant reactive hyperemia (p less than 0.02) was noted only in previously ischemic cord segments. Two animals exhibited no change in somatosensory evoked potentials or spinal cord blood flow despite exclusion of the entire thoracoabdominal aorta, presumably as a result of spinal collaterals. Loss of somatosensory evoked potentials despite adequate distal perfusion indicates that critical intercostal vessels have been excluded from systemic and bypass circulations. Use of evoked potential measurements in both experimental and clinical situations provides a means for assessing adequacy of spinal cord blood flow during cross-clamping and can alert the surgeon to the need for reimplantation of critical intercostal arteries during surgical resection of the thoracoabdominal aorta.     

The effects of subdiaphragmatic vagotomy on circadian corticosterone rhythmicity in rats with continuous or restricted food access

Plasma corticosteroid circadian periodicity was determined in three groups of individual adult male rats. Categories were: postsubdiaphragmatic vagotomy, sham-operated, and controls. Blood was sampled every 4 hours over a 48-hour period with ad lib feeding and after a 13-day period on daytime (0930–1330) restriction of food and water availability. Plasma corticosterone circadian periodicity was normal under ad lib conditions in control, sham-operated, and vagotomized animals. Under food-restricted conditions, both the sham-operated and vagotomized animals exhibited the 12-hour shift in the circadian peak of plasma corticosterone levels that we have previously described in normal animals under such conditions. There were no differences between groups in the total amount of food and water consumed or the percentage of nocturnal food intake on an ad lib feeding schedule. Both vagotomized and sham-operated animals manifested reductions in food intake under conditions of food restriction, although vagotomized consumed less than sham-operated animals. The present data indicate that an intact vagus nerve is not necessary for the establishment of circadian periodicity of plasma corticosterone levels or the shift in the periodicity of corticosteroid secretion produced by a restricted feeding regimen.     

Is trisomy 22 in acute myeloid leukemia a primary abnormality or only a secondary change associated with inversion 16?

In an attempt to confirm the existence of acute myeloid leukemia (AML) with trisomy 22, we studied three patients in whom trisomy 22 imposed as the sole karyotype abnormality. After revision of the karyotypes, however, we were able to identify an inv(16) as the important primary abnormality in all of them. Based on this experience, we investigated whether at least some of the 17 AML cases with trisomy 22 reported so far might possibly have been misinterpreted. Interestingly, ten out of 16 evaluable cases were classified as M4, some of them with bone marrow eosinophilia. As in cases with inv(16), only few metaphases contained trisomy 22. Furthermore, in at least two out of the only four published karyotypes of cases with trisomy 22, an inv(16) is evident and in the other two cases it cannot be ruled out. We therefore believe that at least some of the trisomy 22 cases mentioned in the literature are in fact only secondary changes occurring in AML with an inv(16) and suggest that future reports of AML with trisomy 22 as a specific primary abnormality can only be accepted as such if inv(16) has been excluded with appropriate methods.     

Non-Invasive detection of respiratory effort-related arousals (REras) by a nasal cannula/pressure transducer system

STUDY OBJECTIVES: The published AASM guidelines approve use of a nasal cannula/pressure transducer to detect apneas/hypopneas, but require esophageal manometry for Respiratory Effort-Related Arousals (RERAs). However, esophageal manometry may be poorly tolerated by many subjects. We have shown that the shape of the inspiratory flow signal from a nasal cannula identifies flow limitation and elevated upper-airway resistance. This study tests the hypothesis that detection of flow limitation events using the nasal cannula provides a non-invasive means to identify RERAs. DESIGN: N/A SETTING: N/A PATIENTS: 10 UARS/OSAS and 5 normal subjects INTERVENTIONS: N/A MEASUREMENTS AND RESULTS: All subjects underwent full NPSG. Two scorers identified events from the nasal cannula signal as apneas, hypopneas, and flow limitation events. Two additional scorers identified events from esophageal manometry. Arousals were scored in a separate pass. Interscorer reliability and intersignal agreement were assessed both without and with regard to arousal. The total number of respiratory events identified by the two scorers of the nasal cannula was similar with an Intraclass Correlation (ICC) =0.96, and was essentially identical to the agreement for the two scorers of esophageal manometry (ICC=0.96). There was good agreement between the number of events detected by the two techniques with a slight bias towards the nasal cannula (4.5 events/hr). There was no statistically significant difference (bias 0.9/hr, 95%CI -0.3-2.0) between the number of nasal cannula flow limitation events terminated by arousal and manometry events terminated by arousal (RERAs). CONCLUSION: The nasal cannula/pressure transducer provides a non-invasive reproducible detector of all events in sleep disordered breathing; in particular, it detects the same events as esophageal manometry (RERAs).     

Osteosarcomatosis

A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized.