Distribution of calcium differs in relaxed and contracted myocardial cells of the rat

Myocardial cells from left ventricles of beating hearts of rats were fixed by immersion in an osmium tetroxide solution containing potassium pyroantimonate to study the electron-microscopic distribution of calcium, the cation being precipitated as an electron-opaque salt (calcium antimonate) by this cytochemical technique. The observed myocytes could be divided into two groups according to their contractile state, evaluated by sarcomere length measurements. In contracted cells (mean sarcomere length 1.43 microgram) the intramyofibrillar precipitate was confined to areas of I-bands bordering the A-bands, the intermyofibrillar space showing scarce content in reaction product. Relaxed cells (mean sarcomere length 1.69 microgram) presented a heavy deposition of reaction product over the sarcomeres, the electron-opaque dots being absent on the H and Z bands. The sarcotubular system and mitochondria were also clearly marked by the reaction product. This second pattern of calcium distribution has not been previously described in heart muscle cells and is interpreted as corresponding to the phase of rise of intracellular calcium which is mediated by membrane depolarization. Our results suggests that different bands of heart sarcomeres show different abilities to bind calcium. The I bands retain the cation even in cells under sustained contraction, probably due to their content in calmodulin; Z and M bands are apparently not involved in calcium sequestration, whereas the content in calcium of the A bands seems to be dependent on the contraction-relaxation cycle of heart myocytes.     

Testing the feasibility of DNA typing for human identification by PCR and an oligonucleotide ligation assay

The use of DNA typing in human genome analysis is increasing and finding widespread application in the area of forensic and paternity testing. In this report, we explore the feasibility of typing single nucleotide polymorphisms (SNPs) by using a semiautomated method for analyzing human DNA samples. In this approach, PCR is used to amplify segments of human DNA containing a common SNP. Allelic nucleotides in the amplified product are then typed by a colorimetric implementation of the oligonucleotide ligation assay (OLA). The results of the combined assay, PCR/OLA, are read directly by a spectrophotometer; the absorbances are compiled; and the genotypes are automatically determined. A panel of 20 markers has been developed for DNA typing and has been tested using a sample panel from the CEPH pedigrees (CEPH parents). The results of this typing, as well as the potential to apply this method to larger populations, are discussed.     

Histopathology of staphylococcal mastitis in unbred dairy heifers

Histologic observations of mammary tissue samples from unbred heifers revealed that secretory parenchyma from uninfected quarters was undeveloped, exhibiting small alveoli with a limited luminal area and a large interalveolar stromal area. Tissues from quarters infected with Staphylococcus aureus were less developed, exhibiting less alveolar epithelial and luminal areas and more interalveolar stroma compared with tissues from uninfected quarters. Such quarters also demonstrated minimal secretory activity. Macroscopic and microscopic abscesses were observed in one quarter with S. aureus intramammary infection. Staphylococcus aureus-infected quarters showed greater leukocyte infiltration into mammary parenchymal components and cistern lining compared with uninfected quarters. Quarters infected with non-aureus staphylococci also exhibited greater leukocyte infiltration and greater percentages of interalveolar stroma compared with uninfected controls. Results demonstrated that presence of infection increased leukocytosis into the mammary gland and reduced secretory activity in heifers, suggesting a deleterious effect on future milk production.     

Evaluation of protein A and a commercial bacterin as vaccines against Staphylococcus aureus mastitis by experimental challenge

Protein A and a commercial staphylococcal bacterin were evaluated by experimental challenge with Staphylococcus aureus (ATCC 29740). Thirty cows in first lactation were in three treatment groups, protein A, bacterin, and nonvaccinated controls. Studies were through three lactations and included bacteriological and cytological analyses of quarter milk samples. Rate of intramammary infection with Staphylococcus aureus was similar for vaccinated and unvaccinated cows. Rates of spontaneous cure within each lactation were significantly higher for vaccinated cows. For all three lactations, spontaneous cure rates were 83, 73, and 47% for protein A, bacterin, and control cows. Somatic cell counts were significantly lower for vaccinated cows for quarters infected with Staphylococcus aureus, but no differences were demonstrated for milk production by lactation. Incidence of clinical mastitis was higher in unvaccinated cows, but too few developed for a valid comparison.     

Quantitative PET with positron emitters that emit prompt gamma rays

The purpose of this work was to determine the feasibility of using positron emitting isotopes that emit prompt gammas to acquire quantitative positron emission tomography (PET) data using standard PET instrumentation. Prompt gammas can contaminate PET data by increasing dead time, converting singles into invalid coincidences, and producing multiple coincidences which can lead to the replacement of valid coincidences by invalid coincidences. The measurements in this work were made by scanning point sources containing F-18, Na-22, and Co-60 and studying the effects of the prompt gammas on the PET data, We found that for the Na-22 point source, the annihilation photon coincidence rate was about 25 times the prompt gamma-annihilation photon coincidence rate in the entire active volume of the scanner. With scatter, the Na-22 prompt gamma-annihilation photon coincidence rate was 1.3 times higher than the F-18 scatter coincidence rate. The most significant effect of the prompt gamma was to increase dead time; the dead time correction factor for Cu-60 was 2.4 times higher than the correction factor for N-13 for the same source activity. We conclude that, in many cases, quantitative PET data can be readily obtained with isotopes that emit prompt gammas, using standard PET 2-D instrumentation. However there are some cases, such as 3-D PET, where prompt gammas could significantly contaminate the PET data.     

Comments on The Brain Watchers.

Comments on The Brain Watchers by M. L. Gross (see record 1964-04809-000), which presents a documented account of application of psychological tests, mostly personality, in industry and education at all levels. The present author argues that Gross presents his case with obvious hostility, and that exaggerations, sweeping generalities, and half-truths are found throughout the book and may tempt many serious psychologists (as human beings) to reject him outright. It is suggested that a realistic defense by the psychology profession should include at least two major elements at the beginning. First of all, it is argued that Gross has not revealed anything about test validity which is not common knowledge to any professionally trained psychologist. Second, it should be clearly emphasized that much of the writer's comments pertain to a certain segment of the psychological profession, and that many of his observations have been made on self-appointed testers with no professional status or recognition of any sort. Further, it should be added that we in the profession are much concerned about the unethical and haphazard uses of tests and the unsubstantiated claims of pseudopsychologists, and that we have ethics committees in the American Psychological Association and in most states which are endeavoring to protect the public through certification procedures and public education. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enzymatic cross-linking to improve the handling properties of dough prepared within a normal and reduced NaCl environment

This research examines the use of three enzymes [glucose oxidase (GOX), hexose oxidase (HOX), and xylanase (XYL)] and their combinations [GOX–XYL and HOX–XYL] on the dough handling properties of CDC Plentiful and Stettler wheat cultivars prepared at reduced (1.0% wt. by flour) and normal (2.0% wt. by flour) NaCl levels. Properties investigated include dough rheology, stickiness, and ratio of resistance to extension and extensibility. The inclusion of XYL and its combinations with GOX and HOX increased the stickiness, yielded lower dough strength indicated by rheology, and reduced the ratio of resistance to extension and extensibility. The inclusion of oxidative enzymes yielded a stronger dough, where HOX addition to dough had the lowest stickiness values and highest |G*| values, whereas GOX addition led to the highest ratio of resistance to extension—extensibility. NaCl only had minor effects overall on dough strength and stickiness for the cultivars studied. Overall, superior dough handling properties were observed with oxidative enzyme addition (GOX and HOX) suggesting that the increased crosslinking that occurs could aid in improving low sodium bread dough properties.     

Formation and functionality of whey protein isolate–(kappa-, iota-, and lambda-type) carrageenan electrostatic complexes

The formation of electrostatic complexes between whey protein isolate (WPI) and (κ-, ι-, λ-type) carrageenan (CG) was investigated by turbidimetric measurements as a function of pH (1.5–7.0), biopolymer weight-mixing ratio (1:1–75:1 WPI:CG) and NaCl addition (0–500 mM) to better elucidate underlying mechanisms of interaction. Emulsion stabilizing effects of formed complexes was also studied to assess their potential as emulsifiers. Complex formation followed two pH-dependent structure-forming events associated with the formation of soluble (pH_c) and insoluble (pH_?1) complexes. For both the WPI–κ-CG and WPI–ι-CG mixtures, pH_c and pH_?1 occurred at pH 5.5 and 5.3, respectively, whereas in the WPI–λ-CG mixture values were slightly higher (pH_c = 5.7; pH_?1 = 5.5). In all mixtures, maximum turbidity was found to occur near pH 4.5, before declining at lower pHs. Biopolymer mixing ratios corresponding to maximum OD was found to occur at the 12:1 ratio for both the WPI–κ-CG and WPI–λ-CG mixtures, and 20:1 ratio for WPI–ι-CG mixture. The addition of NaCl disrupted complexation within WPI–κ-CG mixtures as levels were raised, whereas when ι-CG and λ-CG was present, complexation was enhanced up to a critical Na⁺ concentration before declining. Adsorption of CG chains to the small WPI–WPI aggregates during complexation was proposed to be related to both the linear charge density and conformation of the CG molecules involved. Emulsion stability in the mixed systems (12:1 mixing ratio), regardless of the CG type (κ, ι, λ), was significantly higher than individual WPI solutions indicating enhanced ability to stabilize the oil-in-water interface.