Using purified DNA gyrase to supercoil circular plasmid pBR322 DNA, we examined how the linking number attained at the steady state ('static head') varies with the concentrations of ATP and ADP, both in the absence and presence of spermidine. In the absence of spermidine at total adenine nucleotide concentrations between 0.35 and 1.4 mM, the static-head linking number was independent of the sum concentration of ATP and ADP, but depended strongly on the ratio of their concentrations. We established that the same linking number was attained independent of the direction from which the steady state was approached. The decrease in linking number at static head is more extensive when spermidine is present in the incubation, but remains a function of the [ATP]-to-[ADP] ratio. These results are discussed in terms of various kinetic schemes for DNA gyrase. We present one kinetic scheme that accounts for the experimental observations. According to this scheme our experimental results imply that there is significant slip in DNA gyrase when spermidine is absent. It is possible that spermidine acts through adjustment of the degree coupling of DNA gyrase.

Adenosine Diphosphate↗

PubMedDate not supplied

Patient presentation, interview content, and the detection of depression by primary care physicians.

This study was undertaken in order to better understand the detection of depression by primary care physicians. Specifically, we investigated the relationship between information gathered during the course of the medical interview and the subsequent diagnosis of depression. Forty-seven community-based primary care physicians, unaware of the mental health focus of this research, were videotaped in the office setting, as they interviewed two "typical" standardized patients who met DSM-III-R criteria for major depression. One patient presented with headaches and the other presented with palpitations and chest pain. After each interview, physicians were provided with physical findings and results of any diagnostic procedures they ordered, then asked to construct and explicate their differential diagnoses. The two patients were correctly diagnosed as depressed by 53 and 45% of the physicians. Although detection was related to greater amounts of information gathered, inquiry about the DSM-III-R criteria symptoms was generally low, and in no case was sufficient information acquired to make a formal DSM-III-R diagnosis of depression. However, a subset of the DSM-III-R symptoms (those related to disturbances of appetite, sleep, and other neurovegetative functions) were among the reasons cited for inclusion of depression in the differential, as were psychosocial stressors and the patient's appearance. These findings suggest that detection of depression is low by primary care physicians.

Adult↗

PubMedDate not supplied

Reduced serum insulin-like growth factor (IGF) and IGF-binding protein-3 concentrations in two deerhounds with congenital portosystemic shunts.

Explore the source record for details and available documents.

Ammonia↗