An Acoustic Converter Used to Measure Ionizing Radiation Energy Loss

A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·10⁹–6·10¹⁰ particles in a pulse and a pulse length of 70 nsec.     

Reaction of cytochrome P450 with cumene hydroperoxide: ESR spin-trapping evidence for the homolytic scission of the peroxide O-O bond by ferric cytochrome P450 1A2

ESR spin trapping was used to investigate the reaction of rabbit cytochrome P450 (P450) 1A2 with cumene hydroperoxide. Cumene hydroperoxide-derived peroxyl, alkoxyl, and carbon-centered radicals were formed and trapped during the reaction. The relative contributions of each radical adduct to the composite ESR spectrum were influenced by the concentration of the spin trap. Computer simulation of the experimental data obtained at various 5,5-dimethyl-1-pyrroline N-oxide (DMPO) concentrations was used to quantitate the contributions of each radical adduct to the composite ESR spectrum. The alkoxyl radical was the initial radical produced during the reaction. Experiments with 2-methyl-2-nitrosopropane identified the carbon-centered adducts as those of the methyl radical, hydroxymethyl radical, and a secondary carbon-centered radical. The reaction did not require NADPH-cytochrome P450 reductase or NADPH. It is concluded that the reaction involves the initial homolytic scission of the peroxide O-O bond to produce the cumoxyl radical. Methyl radicals were produced from the beta-scission of the cumoxyl radical. The peroxyl adduct was not observed in the absence of molecular oxygen. We conclude that the DMPO peroxyl radical adduct detected in the presence of oxygen was due to the methylperoxyl radical formed by the reaction of the methyl radical with oxygen. At a higher P450 concentration, a protein-derived radical adduct was also detected.     

Choice of design of cryogenic vessels with minimal weight

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 3, pp. 20–22, March, 1991.     

Chronic abdominal pain: role of video-laparoscopic adhesiolysis

Adhesions have been suggested as a possible cause of chronic abdominal pain, but the reports of their etiological role conflict. Lysis of adhesions has been proposed as the therapeutic modality of choice, although the reports of success are controversial. The aim our prospective study was to determine whether laparoscopic adhesiolysis ameliorates chronic abdominal pain in patients with abdominal adhesions. Forty-one patients with chronic abdominal pain lasting for more than 6 months, but with no abnormal findings other than adhesions found at laparoscopy, underwent laparoscopic adhesiolysis. 37 patients (90.2%) were available for follow-up after a median time interval of 18 months (range: 12-41 months). Twenty-two patients (59.4%) were free from abdominal pain and 9 (24.3%) patients reported significant amelioration of their pain. Six (16.2%) patients had no amelioration. In conclusion the laparoscopy is an effective tool for the evaluation of patients with chronic abdominal pain, and laparoscopic adhesiolysis cures of ameliorates chronic abdominal pain in more than 80% of patients.     

Safety of intrauterine contraceptive devices during MR imaging

OBJECTIVE: We report a case of candidiasis of the upper urinary tract that presented as acute renal failure associated with septic syndrome. The patient initially required hemodialysis. Right hydronephrosis and perirenal collection were observed on ultrasound examination. METHODS: A percutaneous nephrostomy was performed. Nephrostomy urine cytology and cultures were positive for Candida tropicalis. An anterograde pyelography showed a 'fungus ball' in the urinary tract. RESULTS: Therapy with oral fluconazole and percutaneous amphotericin B achieved excellent results. CONCLUSIONS: Candidiasic urinary infection of the upper urinary tract often produces obstructive uropathy requiring percutaneous nephrostomy, which can also be used to instill amphotericin B. Combination therapy with amphotericin B and fluconazole can achieve excellent results.     

New advances in the treatment of infertility in women with ovarian failure

Ovarian failure is heterogeneous in etiology and may occur at various points in a woman's life. As such, it may interfere with fertility. Clinical presentation ranges from complete cessation of menses to oligomenorrhea to the continuation of menses with elevated gonadotropins. Various therapies have been used in an attempt to induce fertility, including sex steroids and gonadotropin-releasing hormone agonists to suppress circulating gonadotropin alone or in combination with estrogen or gonadotropin-releasing hormone agonists to induce ovulation. Corticosteroids are also used to overcome autoimmunity. Randomized therapeutic trials are rare and fail to demonstrate any significant improvement in ovulation and pregnancy rates. Donor oocytes have demonstrated high success rates and have proven to be useful in patients with both premature ovarian failure and natural menopause. Pregnancies have been initiated and maintained in women through 60 years of age. Thus, for those accepting of the technique, oocyte donation appears to be the treatment of choice for hypergonadotropic hypogonadism.     

Clinical associations of prenatal ischaemic white matter injury

Neuropathological examinations were carried out at necropsy on 274 cases of intrauterine death or neonatal death at or before three days after birth. Fifty six (20.4%) subjects had evidence of prenatal ischaemic brain damage. On review of the maternal case notes to ascertain antenatal clinical associations there was an increased incidence of intrauterine growth retardation, either based on birth weight for gestational age (odds ratio (OR) 2.0; 95% confidence interval (CI) 1.1 to 3.7) or diagnosed antenatally (OR 2.7; 95% CI 1.3 to 5.6). Oligohydramnios was also more common (OR 2.9; 95% CI 1.2 to 7.0). The association of intrauterine growth retardation and white matter damage remained after excluding fetuses with a major congenital anomaly (OR 2.4; 95% CI 1.1 to 5.1). The findings suggest that chronic intrauterine hypoxia may be associated with damage to cerebral white matter among fetuses and infants who die. The relation between ischaemic white matter damage and cerebral palsy among survivors remains speculative.     

Functional activity of peripheral blood neutrophils of rats during combined effects of hypoxia, hypercapnia and cooling

Functional activity of neutrophilic leukocytes was studied in blood of rats immediately following single and repeated gradual increase in carbon dioxide and decrease in oxygen concentrations with the ambient temperature at 2 to 3 degrees C. Phagocytic activity was shown to alter as the number of phagocytic neutrophilic granulocytes, absorptivity or the phagocytic index, and the coefficient of phagocytosis completeness were elevated and levels of oxygen-dependent and oxygen-independent metabolism were reduced.