Arterial blood pressure response to transient arousals from NREM sleep in nonapneic snorers with sleep fragmentation

STUDY OBJECTIVES: To assess the hemodynamic effects of graded arousals during nonrapid eye movement (NREM) sleep in patients with partial upper airway obstruction during sleep without obstructive sleep apnea/hypopnea, overnight beat-to-beat BP was recorded in six patients. SETTING: At the end of each nonapneic obstructive event, EEG responses were graded as follows: grade 2, grade 1, and grade 0 were defined as increased high-frequency EEG lasting >15 s, 3 to 15 s, and no EEG arousals according to the American Sleep Disorders Association, respectively. MEASUREMENTS AND RESULTS: The following were observed during grade 0, 1, and 2 EEG patterns (mean+/-SD): systolic pressure increased by 7.1+/-1.5, 11.7+/-1.9, and 14.2+/-3.4 (p<0.005), respectively; diastolic pressure increased by 4.6+/-0.6, 6.7+/-1.7, and 9.4+/-3.0 (p<0.005), respectively; heart rate increased by 2.9+/-0.4, 3.9+/-2.2, and 8.6+/-4.6 (p<0.005), respectively. CONCLUSIONS: We conclude that nonapneic-nonhypopneic obstructive events are followed by arterial systemic pressure increases whose magnitude varies with the grade of the arousal.     

Local staging with CT of tumors of the upper urothelium

OBJECTIVE: To evaluate the ability of computerized tomography (CT) to stage transitional cell carcinoma of the upper urinary tract. METHODS: 29 transitional cell carcinoma of the upper urinary tract submitted to nephroureterectomy were retrospectively evaluated. All 29 tumors had preoperative CT scans performed to stage the lesion. The pathological staging was compared to that of CT. RESULTS: 10 of the 29 tumors had CT evidence of tumor extension and 19 had localized noninvasive tumor on CT. Of the 10 patients with CT findings of tumor extension, 2 (20%) had superficial tumors and 8 (80%) had tumors that invaded into the adventitial fat, renal parenchyma or perirenal fat (pT3, pT4). Of the 19 patients with localized noninvasive tumor on CT, 13 (68%) had superficial tumors and 6 (32%) had pT3 or pT4 tumors. CT sensitivity for tumor invasion was 57% with a specificity of 87.5%. CONCLUSIONS: Our analysis shows that CT is of limited value in staging these tumors. When CT demonstrates direct tumor extension through the renal pelvic or ureteral wall, it is a sensitive indicator of high-stage tumor. However, the results obtained in low stage tumors must be viewed with caution.     

Membrane-bound calmodulin in Xenopus laevis oocytes as a novel binding site for melatonin

Melatonin has been suggested as a physiological antagonist of calmodulin. In this work, we have characterized melatonin binding sites in Xenopus laevis oocyte membranes. Binding of [125I]melatonin by X. laevis oocyte membranes fulfills all criteria for binding to a receptor site. Binding was dependent on time, temperature, and membrane concentration and was stable, reversible, saturable, and specific. The binding site was also pharmacologically characterized. Stoichiometric studies showed a high-affinity binding site with a Kd of 1.18 nM. These data are in close agreement with data obtained from kinetic studies (Kd=0.12 nM). In competition studies, we observed a low-affinity binding site (Kd=63.41 microM). Moreover, the binding site was characterized as calmodulin. Thus, binding was dependent on calcium and blocked by anti-CaM antibodies in a concentration-dependent manner. Calmodulin inhibitor chlorpromazine also inhibited binding of the tracer. From these results, it is suggested that membrane-bound calmodulin acts as a melatonin binding site in Xenopus laevis oocytes, where it might couple cellular activities to rhythmic circulating levels of melatonin. This hypothesis correlates with the previous findings describing melatonin as a physiological antagonist of calmodulin.     

Real-time X-ray diffraction study at different scan rates of phase transitions for dipalmitoylphosphatidylcholine in KSCN

A questionnaire survey was carried out to examine the attitudes and practices of Australian and New Zealand intensivists with regard to brain death and organ donation. A return rate of 82.5% was achieved. Fifty-eight per cent had written evidence of their own wishes to donate organs and 94% would agree to donation from a dependent. At least one intensivist is involved in certifying brain death on 95% of occasions. Intensivists are involved in the request for organ donation over 90% of the time although one-third do not believe that it is their role to request organ donation. Although two-thirds believe that the family should always be approached for organ donation, another 52 out of 254 indicated that it was their (the intensivist's) role to decide if families should be asked for organ donation. Possible reasons for not requesting are language or other communication problems, perceptions of cultural differences and degrees of family distress. Twenty per cent of respondents do not provide haemodynamic support before brain death confirmation. Australian and New Zealand intensivists overwhelmingly support the concept of brain death, current methods of confirmation of brain death, organ donation and transplantation. Possible reasons behind loss of potential donors include decisions not to resuscitate both before and after brain death is confirmed. Perceptions of family grief and cultural differences clearly inhibit requests for organ donation. A very few units have an effective policy on approaching families about organ donation. Intensivists have almost exclusive control over requests for organ donation and thus bear a full professional responsibility for this element of hospital practice.     

Vertebral artery trauma

The developmental consequences of paternal exposure to acrylamide (50 mg/kg i.p. for 5 days) were assessed in preimplantation embryos. There was a significant increase in the proportion of morphologically abnormal embryos after postmeiotic treatment during spermatogenesis (88.7% vs. 14.8% in control). Abnormal embryos had an average of 1.8 +/- 3.5 cells and > 80% had at least one fragmented nucleus. In addition, morphologically normal embryos were significantly delayed (34.3 +/- 12.8 cells per embryo vs. 57.6 +/- 15.7 in control, P < 0.001). Acrylamide caused 10- and 20-fold increases in frequencies of cells with micronuclei (MN) in morphologically normal and abnormal embryos, respectively (41 and 93 MN per 1,000 cells). Both centromere-negative (MN-) and centromere-positive (MN+) were induced. Nuclei of abnormal embryos were significantly larger (900 microm2 vs. 250 microm2) than controls. In addition, MN of abnormal embryos were larger than those of normal embryos (21.2 microm2 vs. 6.5 microm2, P < 0.01). Among control embryos, MN+ were significantly larger than MN- (P < 0.05). These findings suggest that the preimplantation embryo is a sensitive indicator of paternally transmitted effects on early development. Multiple mechanisms appear to be involved, including cytogenetic damage, proliferation arrest/delay, and fertilization failure. Future studies are needed to establish how induced cytological defects in preimplantation embryos contribute to birth defects and other postimplantation abnormalities.