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The dnaHlocus is the fourth gene to be identified as required for deoxyribonucleic acid polymerization in Escherichia coli. A temperature-sensitive mutant defective in this gene exhibited an abrupt decrease in rate of deoxyribonucleic acid synthesis when shifted to 42 C. The locus mapped in the proC-purEregion of the chromosome by conjugation and was co-transducible with purE. dnaH+is carried on the F′13episome and is dominant over the dnaH−mutation.

Three mutants of Escherichia coliK-12 which form filaments during 42 C incubation have been characterized. The mutant strains AX621, AX629, and AX655 continued to grow and to synthesize deoxyribonucleic acid at 42 C for 150 to 180 min, after which time growth ceased. When cultures of the mutants were transferred from 42 to 28 C, septation of the filaments began after a 25- to 30-min period and continued at a greater than normal rate until no filaments remained. Addition of chloramphenicol at the time of transfer from 42 to 28 C prevented cell division in strain AX655 and caused lysis of strains AX621 and AX629. The temperature sensitivity mutation in each strain mapped near leu. For strain AX621, the mutation was specifically located between leuand nadCby P1 transduction. Properties of these strains are compared with those of other cell division mutants.

A study has been made of the method used for extracting the complex formed between thallium(III) and PhMBP. It has been demonstrated that thallium(III) can be readily extracted as a complex with PhMBP by organic solvents at low pH. The extraction of thallium(III) has been studied as a function of pH, concentration of reagent, nature of solvent, duration of contact of the phases and concentration of thallium(III). It has been established that thallium(III) forms a complex with PhMBP of the type MAn, where n=3. The stability constants and distribution constant of the neutral complex has been calculated by the method of Leden-Rydberg.

Endogenous NAD levels are approximately equal in erythrocytes and in reticulocytes. After whole-body irradiation with 600 R, NAD concentrations progressively decrease over the following 4 days.NAD synthesis increases after irradiation in both kinds of cells.In normal reticulocytes NAD synthesis is more accentuated than in erythrocytes. In normal erythrocytes, maximum synthesis was obtained in vitro in a system with nicotinamide, glucose, glutamine and methylene blue, and in the erythrocytes of irradiated rabbits in a system with nicotinic acid, inosine, glutamine and methylene blue.These findings suggest that, after irradiation, disorders appear in hexokinase activity and in the cellular oxido-reducing potential.Mg2+ ion is a powerful inhibitor of NAD synthesis in the erythrocytes of irradiated animals in the presence of inosine and of glucose.

The effect of irradiation (600 R) of rabbit erythrocyte NAD and NADP was studied at various intervals after whole-body irradiation of the animal. The decrease found in both pyridinnucleotides progressed with time. The decrease in NAD and NADP was significant after the first hour of irradiation. In the cells of the irradiated animals an increase was found in NAD-ase and NADP-ase activity, which accounts for the decrease in pyridinnucleotide concentrations. Nicotinamide inhibits the activity of enzymes both in normal and irradiated animal erythrocytes. The protective effect of nicotinamide is more marked on the NADP than on the NAD system.

Effective communication with the patient comes after learning all we can about him through the telephone conversation, through what he writes down for us, and through personal contact; after uncovering and discussing fears within the patient that may act as blocks to his acceptance of necessary treatment; and after a thorough program of patient education.

The significance of borderline magnetic resonance (MR) findings that are equivocal for a tear of the knee meniscus remains uncertain. Given their higher signal-to-noise ratio (SNR) and greater spatial resolution, these equivocal meniscal tears could be expected to be less frequent using a 3.0T MR system.

BackgroundSome orthopedic surgeons request a posterior approach for shoulder magnetic resonance (MR) arthrography, especially in patients with anterior shoulder instability, to avoid interpretive difficulties in differentiating anterior extraarticular contrast injection when using an anterior approach from ventral leakage of contrast.PurposeTo determine the occurrence of ventral leakage of contrast in shoulder MR arthrography when using a posterior approach.Material and MethodsRetrospectively, we included 73 consecutive patients who underwent shoulder MR arthrography (1.0 Tesla) using the posterior approach. Three unsuccessful procedures were excluded. Ventral leakage of contrast, defined as contrast seen around the musculus subscapularis without distention of the posterior capsule, was recorded. Descriptive statistics were used.ResultsSeventy shoulders were included. Forty-one left shoulders were involved (59%). Mean age of patients was 49 years (range, 17–76 years). Thirty-five patients were women (50%). Ventral leakage of contrast was seen in 12 shoulders (17%).ConclusionAs ventral leakage of contrast was seen in a substantial number of cases when using a posterior approach in shoulder MR arthrography, the use of a posterior approach is advised to avoid misinterpretation of ventral contrast leakage with accidental extra articular contrast injection, and to increase confidence in the final radiological diagnosis.

The sensitivity of the outer and cytoplasmic membranes of Escherichia colito detergent was examined by isopycnic sucrose density gradient centrifugation. Sodium lauryl sarcosinate (Sarkosyl) was found to disrupt the cytoplasmic membrane selectively under conditions in which Triton X-100 and dodecyl sodium sulfate solubilized all membrane protein. These results were verified by gel electrophoresis; membrane proteins solubilized by Sarkosyl were identical to those of the cytoplasmic membrane. The presence of Mg2+during treatment with Sarkosyl was found to afford partial protection of the cytoplasmic membrane from dissolution.

Twenty-five strains of Clostridium sordelliiwere divided into two groups on the basis of spore fine structure. Sixteen strains formed spores with smooth tubular appendages, and nine strains formed spores which lacked appendages. The other properties of the 25 strains were relatively constant. Since the minor strain variability which was encountered did not correlate with spore appendage status, fragmentation of this species on the basis of spore appendage status is not advocated.

The relationship between iron content and turbidity in filter effluent and their effect on filter life are examined here. Also reported is the best method of obtaining continuous control of iron content.

Die Diffusionsmethode eignet sich sehr gut zur Herstellung von radioaktiven Kryptonaten. In dieser arbeit ist die Versuchseinrichtung der Diffuysionskryptonierung fur das Temperaturgebiert 20…300°C und bis zu einem Druck von etwa 8 ata beschrieben. Abschlieβend sind einige Beispiele fur die Krysptonierung anorganischer Verbindungen angegeben einschlieβlich der Kryptonierungs-bedingungen und der erreichten Werte der relativen spezifischen Aktivitaten.

Dette »sogn« er alene naesten like stort som Buskerud fylke. Takket vaere malmbrytningen og jernbanen sprang folketallet op fra 4279 i 1890 til 20170 i 1933, men ennu lever her 63 flyttlappfamilier. Reinantallet ligger noe over 30000. Gällivare strekker sig langt vest i fjellet, helt til riksgrensen, og Gällivare-lappene drog tidligere under sommerbeitingen helt ned mot de norske bygder i Tysfjord og Skjomen. For vel hundre år siden fikk Tysfjord et tilskudd av Gällivare-lapper, saerlig utarmede reinnomader som flyttet over til Norge, slo sig ned ved fjorden og blev bumenn. Efter at forbindelsen med de norske bygder utigjennem århundret stadig blev svakere, er en del gått over til å drive flske og jakt som hovednaering. Ved siden av flyttlappene fantes der i 1934 i Gällivare 23 slike flskerfamilier.

The study of exchange reaction kinetics between sulfur-35 and organic compounds which contain sulfur can be made much easier by use of radiochromatography. Activity ratios of the components of the reaction mixture can be estimated by use of very small amounts of radioactive materials. The reaction need not be halted and individual components need not be isolated. Any degradation of reacting substances can be measured quantitatively at the same time.

The purpose of this paper is to present some of the advantages of the endoscopic method of resection of tumors of the bladder. It is by no means proposed that all such tumors be treated by endoscopic means. It is recognized and admitted that open operation is the method of choice in certain types of tumors of the bladder, especially if they are located in the free portion of the bladder. In the majority of these tumors, however, treatment by means of endoscopic surgery offers more satisfactory results than open surgery.In successful management of tumors of the bladder the most important factor is early diagnosis. Tumors which are discovered in an early stage are more likely to be curable by endoscopic means. Tumors found early are less likely to be infiltrating, are more likely to be pedunculated. Tumors found early are less likely to be malignant. Although these facts

Recently, methotrexate has been suspected of causing a severe pulmonary disease when administered for a long term to patients with acute leukemia in remission. Both pulmonary and liver disease developed in a patient with psoriasis after five years of weekly methotrexate therapy.

The ordinary piece of rubber tubing used as a tourniquet in intravenous medication and drawing of blood samples has certain disadvantages. As it is commonly used, the binding loop forms an undesirable bulging against the skin, it is released with a jerk that is apt to cause the needle to leave the vein, and it takes some care to keep the free ends from the sterile field.The running bow line tourniquet consists of the usual rubber tubing with a 2 or 3 inch loop at one end. This can be made with a heavy rubber band or by sewing.The open end is slipped through the loop so as to form a running bow line just above the elbow. Traction is exerted on both ends, and the loop is pushed down snugly against the arm and released. It will hold firmly. Steady pressure against the loop with the thumb