Interaction of the DNA untwisting enzyme with the SV40 nucleoprotein complex.

The SV40 nucleoprotein complex which was isolated from infected CV-1 cells did not possess an active DNA untwisting enzyme. The superhelix density of the DNA in the chromatin complex was unchanged after treatment with purified rat liver DNA untwisting enzyme. However, in the presence of ethidium bromide (1 microgram/ml) the superhelix density was changed. Moreover, the nicked intermediate in the DNA untwisting reaction could be detected using the chromatin DNA as a substrate. These results show that the DNA in the SV40 chromatin which is accessible to the DNA untwisting enzyme is under no topological strain.     

The staging and treatment of epithelial ovarian cancer.

Recent advances in the staging of ovarian cancer have suggested that many patients with apparently localized (stage I or II) disease have occult dissemination within the abdomen. Approximately 20% of patients classified at laparotomy as having stage I or II ovarian cancer are found by lymphangiography to have abnormal retroperitoneal lymph nodes. In many other patients advanced disease is also detected by peritonescopy; with this technique metastases are often discovered on the undersurface of the right diaphragm. These findings may help explain the high rates of recurrence after surgical resection or pelvic irradiation, or both, in patients with localized disease. Studies are in progress to determine whether modification of the radiotherapy field to include the right diaphragm will improve survival. Along with improved staging, histologic grading of the degree of anaplasia of the tumour tissue may permit more precise determination of prognosis and therefore better design of therapy. Adjuvant radiotherapy has not yet been shown to improve the survival of patients with stage I disease, but the 5-year survival of patients with stage II disease is greater for those receiving postoperative radiotherapy than for those undergoing surgery alone. For most patients with advanced disease radiotherapy is palliative only and carries a high risk of long-term complications. Numerous chemotherapeutic agents used singly can produce an objective response by tumour. Preliminary data suggest that combination chemotherapy can increase the rate of objective response, but a longer follow-up period is necessary to determine whether this form of therapy can improve survival.     

Rallinyssus sorae sp. n. (Acari: Dermanyssidae: rhinonyssinae) from the nasal passages of the sora, Porzana carolina (Aves: Rallidae)

Rallinyssus sorae sp. n. is described from the nasal turbinates of the sora, Porzana carolina, collected in Maryland and Ohio. The new species is most similar to Rallinyssus verheyeni Fain but differs in number of setae on the female ventral opisthosoma, structure of the fixed and movable digits of the male and female chelicerae, chaetotaxy of legs I to IV, and presence of a sternal plate in the male. The taxonomy and host-parasite relationships of the various species of Rallinyssus are discussed.     

Effectiveness of out-of-hours biochemistry investigations.

A survey was carried out of doctors who used their out-of-hours biochemistry service to find out why requests for investigations were made, how often the results altered patient management, and whether they could define areas where investigations were unproductive. Of 107 questionnaires distributed, 147 (88%) were completed. In 86% the requests were for diagnosis or immediate patient management and in 35% the results actually altered management. Senior clinical staff were more efficient than their juniors in instigating biochemical investigations that proved to be effective. In no instance where the clinical staff predicted that it was unlikely that the results would alter management was management altered. It is suggested that joint reviews of case notes by junior and senior clinical staff would prove to be the most appropriate way to increase the effectiveness and efficiency of clinical investigation.     

Carbohydrate nutrition of claviceps purpurea for alkaloid production related to the osmolality of media

Summary The effects of most frequently used carbohydrates and osmolalities of media on the growth and productivity ofClaviceps purpurea in submerged cultures were investigated. The maximum alkaloid yield was obtained with 20% mannitol as well as with 10% mannitol when 2% NaCl was added to the medium and the osmolality about 1 osmol/kg H₂O was established at the end of fermentation. Increased or decreased osmolality of the medium had a negative influence on fungal growth and alkaloid production. Almost the same effect was observed with sucrose as with mannitol, whereas with glucose only maximal growth was achieved.     

Effect of inhibitors of elongation factor Tu on the metabolic regulation of protein synthesis in Escherichia coli.

By using inhibitors of elongation factor Tu (L-1-tosylamido-2-phenylethyl chloromethyl ketone [TPCK] and kirromycin), we determined the effect of elongation factor Tu inhibition on the synthesis of individual components of the translation machinery. The rates of synthesis of individual proteins were measured in double-label experiments using a two-dimensional gel system. TPCK inhibition produce a coordinate decrease in the differential synthesis rates of all components of the translation machinery examined in these experiments. On the other hand, kirromycin inhibition increased the differential synthesis rates of some translation components and decreased the differential synthesis rates of others. These results suggest that the metabolic regulation of synthesis of various translation proteins is not mediated through a common signal.     

Catechol and phenol degradation by a methanogenic population of bacteria

An anaerobic population of bacteria became acclimated to catechol and phenol in 32 and 18 days, respectively. Evidence from carbon balance measurements indicates that the aromatic ring is cleaved and that the products are stoichiometrically fermentable to methane and carbon dioxide.     

Measurement of prostaglandin F2α levels in cerebrospinal fluid of febrile and afebrile patients with advanced cancer

Prostaglandin F_2α levels were measured by radioimmunoassay in 95 samples of unextracted human cerebrospinal fluid obtained from 73 patients with advanced cancer. Concentrations okf PGE were too low to be reliably determined by this method using the commercially available kits. Forty-six of the samples assayed contained <25pg/ml PGF_2α. The remaining levels ranged from 25 to 1154 pg/ml c.s.f.; the majority contained less than 200pg/ml. A possible correlation was found between elevated c.s.f. granulocyte count and increased PGF_2α. A similar relationship was found with regard to protein. These studies failed to demonstrate a correlation between elevated levels of PGF_2α in cerebrospinal fluid and any pathophysiologic condition.     

The second polar lobe of theSabellaria cementarium embryo plays an inhibitory role in apical tuft formation

Summary The embryo ofSabellaria cementarium (Polychaeta) forms a polar lobe at each of the first two cleavage divisions which becomes absorbed into one of the blastomeres at the end of the division. Lobe removal experiments show that the polar lobe preceding first cleavage is necessary for the development of the apical tuft and the posttrochal region of the trochophore larva. The polar lobe preceding second cleavage is smaller than the first polar lobe and is necessary only for post-trochal region development. In blastomere isolation experiments, isolates containing the C but not the D blastomere form apical tufts. Isolates containing the D but not the C blastomere do not form apical tufts. When the polar lobe preceding second cleavage is removed and the C and D blastomeres are separated and raised in isolation, each can form an apical tuft. When the second cleavage is equalized with sodium dodecyl sulfate (SDS) such that both the C and the D blastomeres receive second polar lobe material, no apical tuft is formed. These results suggest that apical tuft determinants are distributed to both the C and D blastomeres at second cleavage but that the second polar lobe contains an inhibitor for apical tuft formation which is shunted to the D blastomere after the completion of second cleavage.