Radiosensitivity of atomic bomb survivors as determined with a micronucleus assay

We have developed a system in which a unique double-stranded break (DSB) can be introduced into a yeast chromosome during mitotic growth. The recognition site for the endonuclease I-SceI was inserted at different places in the yeast genome in haploid and diploid cells expressing this endonuclease. Induction of the break in haploids results in cell death if no intact copy of the cleaved region is present in the cell. If such a copy is provided on a plasmid, as an ectopic gene duplication, or on a homologous chromosome, the break can be repaired. Repair results in two identical copies in the genome of the locus which has been cut. We call this phenomenon homozygotization by reference to diploids heterozygous for the cut site in which repair leads to homozygosis at this site. We have compared the efficiencies of repair in the various topological situations examined, and conclude that some mechanism must search for regions of homology to both sides of the DSB and that repair is successful only if the homologies are provided by the same template molecule.     

Bone demarcation of the temporomandibular joint. Validity of clinical assessment of bone thickness by means of CT

OBJECTIVE: To study the effect of induced hypoglycaemia on serum levels of the placental hormones oestriol, human placental lactogen, placental growth hormone and progesterone in the third trimester of pregnancy. DESIGN: A prospective experimental investigation. SETTING: High risk pregnancy unit and diabetes research unit at Karolinska Institutet Danderyd Hospital, a university hospital. PARTICIPANTS: Ten women with insulin-dependent diabetes mellitus in the third trimester of pregnancy. METHODS: Venous blood samples were collected every 15 minutes for analyses of oestriol, progesterone, human placental lactogen and placental growth hormone, during the 150 min of a hyperinsulinaemic hypoglycaemic clamp, which maintained arterial blood-glucose level of about 2.2 mmol/l. MAIN OUTCOME MEASURES: Levels of analysed placental hormones during hypoglycaemia. RESULTS: A statistically significant increase was observed in placental growth hormone during hypoglycaemia (P < 0.0001), whereas the placental hormones progesterone, human placental lactogen and oestriol did not show changes of clinical significance. CONCLUSIONS: The increase in placental growth hormone indicates that the placenta is an endocrine organ which may take an active part in acute metabolic processes, such as here in the hormonal counterregulation of hypoglycaemia.     

Failure of postexposure treatment of rabies in children

In the female mouse, dapsone (50-500 mg kg-1, p.o.) caused a dose-related methaemoglobinaemia which peaked at 0.5-1 h with recovery to baseline values occurring by 4 h. Cimetidine (100 mg kg-1, p.o.), a known inhibitor of several hepatic P450 isozymes administered 1 h before dapsone, prevented the methaemoglobinaemia. In-vitro, dapsone required activation by mouse hepatic microsomes to cause methaemoglobin formation in mouse erythrocytes and cytotoxicity to human mononuclear leucocytes. In both instances, the toxic effects were markedly reduced by cimetidine. Daily dosing of mice with dapsone (50 mg kg-1, p.o.) for 3 weeks induced a blood dyscrasia, characterized by a fall of platelet and white blood cell counts, which was inhibited by cimetidine (100 mg kg-1, p.o. daily). It is concluded that an active metabolite of dapsone arising from a P450-dependent pathway is involved in the genesis not only of the methaemoglobinaemia but also the blood dyscrasia arising from repeated administration of the drug in this species.     

Using humorous programs as a vehicle for humorous commercials

Many programs and commercials use humor to entertain and persuade viewers. This research examines the effect of levels of humor in program context on commercials and the perceptions of the products they advertise. Effects of humor levels in the commercials themselves are examined, as are effects of gender on perception of humor and product image. Increased program humor was detrimental to recall of products advertised. Gender, however, interacted with program humor levels. Products were viewed less negatively by men when they were exposed to commercials in a more humorous program context. The type of humor may explain why this did not hold for women because humor of a crass or sexual nature holds lower appeal for females. An increased level of commercial humor was found to be beneficial to recall and purchase intention.     

Recombinant hepatitis A virus antigen: improved production and utility in diagnostic immunoassays

Hepatitis A virus (HAV) immunoassays use cell culture-derived HAV antigen to detect HAV-specific antibodies. The current method of production of HAV antigen in tissue culture is time-consuming and expensive. We previously expressed the HAV open reading frame in recombinant vaccinia viruses (rV-ORF). The recombinant HAV polyprotein was accurately processed and was assembled into subviral particles. These particles were bound by HAV-neutralizing antibodies and were able to elicit antibodies which were detected by commercial immunoassays. The present investigation compared the production of HAV antigen by standard tissue culture methods to the production of HAV antigen with the recombinant vaccinia virus system. In addition, HAV and rV-ORF antigens were assessed for their utility in diagnostic immunoassays. Serum or plasma samples from HAV antibody-positive and antibody-negative individuals were evaluated by immunoassay that used either HAV or rV-ORF antigen. All samples (86 of 86) in which HAV antibody was detected by a commercial enzyme-linked immunosorbent assay (ELISA) also tested positive by the recombinant antigen-based immunoassay (VacRIA). Similarly, all samples (50 of 50) that were HAV antibody negative also tested negative by the VacRIA. The lower limit of detection of HAV antibody was similar among immunoassays with either HAV or rV-ORF antigen. Thus, in the population studied, the sensitivity and specificity of the VacRIA were equivalent to those of the commercial ELISA. Since production of recombinant antigen is faster and less expensive than production of traditional HAV antigen, the development of diagnostic HAV antibody tests with recombinant HAV antigen appears warranted.     

Monteggia fractures in adults

The records concerning ten consecutive years of experience with Monteggia fractures in adult patients at a level-one trauma center were retrospectively reviewed. Forty-eight patients who had been followed for a minimum of two years (average, 6.5 years; range, two to fourteen years) were identified. There were twenty-five women and twenty-three men, and the average age was fifty-two years (range, eighteen to eighty-eight years). According to the classification of Bado, there were seven type-I, thirty-eight type-II, one type-III, and two type-IV injuries. Twenty-six patients (68 percent) who had a Bado type-II fracture had an associated fracture of the radial head; ten of these patients also had a fracture of the coronoid process as a single large fragment. The ulna was fixed with a tension band-wire construct supplemented with screws in three patients (all of whom had a Bado type-II fracture). An ulnar diaphyseal fracture was fixed with an intramedullary Steinmann pin in one patient. The remaining patients had fixation with a plate and screws. The fracture of the radial head was treated with either complete or partial excision of the fragments in twelve patients (with replacement with a silicone prosthesis in two), open reduction and internal fixation in ten patients, and no intervention in four patients. Nine patients, all of whom had a Bado type-II fracture, needed a reoperation within three months after the initial operation; five had revision of a loose ulnar fixation device, three had resection of the radial head, and one had removal of a wire that had migrated from the radial head into the elbow articulation. Other important complications included proximal radioulnar synostosis in three patients, ulnar malunion in three, posterolateral rotatory instability of the ulnohumeral joint in one, and instability of the distal radioulnar joint in one. At the most recent follow-up examination, which was performed after all of the reoperations and reconstructive procedures had been done, the average score according to the system of Broberg and Morrey was 86 points (range, 15 to 100 points). The result was excellent for eighteen patients, good for twenty-two, fair for two, and poor for six. Six of the eight patients who had an unsatisfactory (fair or poor) result had had a Bado type-II fracture with a concomitant fracture of the radial head. These unsatisfactory results were related to a malunited fracture of the coronoid process in two patients, a proximal radioulnar synostosis in one, a malunited fracture of the coronoid process and a proximal radioulnar synostosis in one, a malunion of the ulna in one, and painfully restricted rotation of the forearm after operative fixation of a comminuted fracture of the radial head in one. The other two unsatisfactory results were in a patient who had had a Bado type-I fracture and in one who had had a Bado type-IV fracture. The results of the present series are much better than those reported in most earlier studies, suggesting that stable anatomical fixation of the ulnar fracture (including associated fracture fragments of the coronoid process) with a plate and screws inserted with use of current techniques of fixation leads to a satisfactory result in most adults who have a Monteggia fracture. The posterior (Bado type-II) fracture is the most common type of Monteggia fracture in adults. Problems with the elbow related to fractures of the coronoid process and the radial head, which are common with Bado type-II Monteggia fractures, remain the most challenging elements in the treatment of these injuries.