Pseudorandom testing technique for the characterization of local hemodynamic control

Summary In order to investigate the low frequency properties of renal and femoral hemodynamic variables, pseudorandom testing techniques were used. The arterial flow of each bed, in separate experiments, was modulated by a low amplitude signal based on a pseudorandom binary sequence (PRBS) generated by digital computer.The cross-correlation functions between input flow and arterial pressure, venous pressure, and venous flow exhibit damped oscillations in all cases. These responses are parameterized in terms of a damping ratio () and an undamped natural frequency _n for a second order model. The parameters of the model are dependent upon the state of the bed as defined by mean arterial and venous pressures, mean flow through the bed, resistance, and oxygen consumption.The results of this study offer further insight into the dynamic low frequency autoregulation phenomenon for the renal and femoral beds of the dog.Supported by NIH Grant HE 11747.     

f1 Coat protein synthesis and altered phospholipid metabolism in f1 infected Escherichia coli

The phospholipid composition of cytoplasmic membranes prepared from bacteria grown in the presence of [³²P]phosphate and infected with f1 wild type and f1 amber mutant bacteriophages was determined. Ninety minutes after infection with f1 amber mutants in genes 1, 3, 4, 5, 6, and 7 the percentage of cardiolipin was increased from the level in uninfected bacteria of 5% to about 20–35%, and the percentage of phosphatidylethanolamine was decreased from 70% to about 50–60%. The phospholipid composition of cytoplasmic membranes from bacteria infected with a phage containing an amber mutation in the coat cistron (gene 8) did not differ from that of uninfected bacteria. Although late in infection there were no detectable alterations in phospholipid metabolism in wild type infected bacteria, transient alterations in phospholipid metabolism occurred in these bacteria 10 to 20 min after infection. During this time period, the f1 coat protein was found to be rapidly synthesized but was not being packaged into mature phage and released from bacteria. Both the long-term alterations of phospholipid metabolism found in the amber mutant infected bacteria and the transient alterations found in wild-type infected bacteria resulted from an increase in the rate of synthesis of phosphatidylglycerol and cardiolipin and a decrease in the rate of synthesis of phosphatidylethanolamine. These results are discussed in terms of the relationship between the accumulation of f1 coat protein in infected bacteria and the observed alterations in phospholipid metabolism.     

Asthma/Emphysema Complication of Electroconvulsive Therapy: A Case Study

The authors describe an elderly depressed patient with asthma/emphysema who developed severe postictal bronchospasm immediately after one electroconvulsive treatment. Possible problems and considerations in treating such patients are discussed.     

Does your hospital need a robot or a management trainer?

Executives of small hospitals and home health services have heard that this is the Age of Computers, Telecommunications, Robotics, and Gene Engineering, and they wonder if their organizations might benefit from the high technology and advanced management tools employed by big corporations and “leading edge” hospitals. But they are too tired and busy to greatly expand their technical/managerial expertise, especially since there are so many choices among possible innovations, ranging from robotics to management training, each choice demanding different new expertise, and each requiring an investment of time and energy. We helped several health care executives to identify their options for innovation. We offered a scoring scheme to sort out the innovation options (a simple but effective way to decide what innovation would be “right” for their organization), and a simple, “back of the envelope” tutorial on robotics in health care. The principle is to allow the administrators to make a quick evaluation of the paths they might wish to travel. Our point here is that for every “natural-born” innovator, there must be dozens of interested but uncommitted persons who need some gentle, simple help. To the extent that the diffusion of medical systems depends on a mass market, these fence-sitters must receive help and guidance.     

Baseline Assessment of Circulating MicroRNAs Near Diagnosis of Type 1 Diabetes Predicts Future Stimulated Insulin Secretion

Type 1 diabetes is an autoimmune disease resulting in severely impaired insulin secretion. We investigated whether circulating microRNAs (miRNAs) are associated with residual insulin secretion at diagnosis and predict the severity of its future decline. We studied 53 newly diagnosed subjects enrolled in placebo groups of TrialNet clinical trials. We measured serum levels of 2,083 miRNAs, using RNA sequencing technology, in fasting samples from the baseline visit (<100 days from diagnosis), during which residual insulin secretion was measured with a mixed meal tolerance test (MMTT). Area under the curve (AUC) C-peptide and peak C-peptide were stratified by quartiles of expression of 31 miRNAs. After adjustment for baseline C-peptide, age, BMI, and sex, baseline levels of miR-3187-3p, miR-4302, and the miRNA combination of miR-3187-3p/miR-103a-3p predicted differences in MMTT C-peptide AUC/peak levels at the 12-month visit; the combination miR-3187-3p/miR-4723-5p predicted proportions of subjects above/below the 200 pmol/L clinical trial eligibility threshold at the 12-month visit. Thus, miRNA assessment at baseline identifies associations with C-peptide and stratifies subjects for future severity of C-peptide loss after 1 year. We suggest that miRNAs may be useful in predicting future C-peptide decline for improved subject stratification in clinical trials.     

A prospective study of the accuracy of preoperative computed tomographic staging of patients with biopsy-proven rectal carcinoma

From June 1983 to January 1986, 91 patients with biopsy-proven adenocarcinoma of the rectum had computed tomographic scans of the pelvis performed before treatment as part of a "sandwich" radiotherapy-surgery regimen. Two experienced diagnostic radiologists performed locoregional staging of all scans according to the University of California at San Francisco criteria; one of these radiologists repeated this staging at a later time to test the reproducibility of a single observer. Staging was performed without the use of any other radiographic studies or of any clinical information except the patients' age, sex, and the diagnosis of rectal carcinoma, to test the value of computed tomographic scans alone for staging. Agreement between the two stagings performed by the first observer was 51 percent, and interobserver agreement was only 37 percent. Agreement with Dukes' staging was only 33 percent. Therefore, preoperative pelvic computed tomographic scanning of primary rectal adenocarcinoma should not be relied upon for staging or for the selection of patients for treatment options.