A simple method for quantifying tremor in rodents

A simple and accurate device to evaluate frequency and intensity of involuntary tremor is described. Discrete and quantifiable measures of tremor could be obtained in terms of vertical (i.e., absolute effects at a given time) and horizontal (i.e. temporal) changes. The technique was evaluated employing dosages of physostigmine 0.1-0.7 mg/kg. Applications to other behavioral indices, such as locomotor activity and wet-dog shakes, are discussed.     

Detection of Ureaplasma urealyticum in endotracheal tube aspirates from neonates by PCR

A PCR-based test was optimized for the detection of Ureaplasma urealyticum from neonatal respiratory specimens, with primers directed against the multiple-banded antigen gene (L. J. Teng, X. Zheng, J. I. Glass, H. Watson, J. Tsai, and G. H. Cassell, J. Clin. Microbiol. 32:1464-1469, 1994). Endotracheal tube aspirates (225) from 103 low-birth-weight neonates (<1,250 g) were taken, when possible, at days 0, 4, and 14 after birth and examined by culture and by PCR. Of 77 specimens positive by either method, 73 were detected by PCR and 60 were detected by culture. Overall, 36% of the neonates were positive for U. urealyticum by either method. Of 16 patients with PCR-positive-culture-negative results, 13 had positive cultures at another sampling point, and one additional patient had a twin with positive cultures. Of 11 patients with day 0 specimens positive by PCR alone, 9 subsequently became culture positive, demonstrating the utility of this test in early detection. Multiple serovars were present in over 50% of positive specimens, with serovars 3 and 14 in combination being most prevalent. The amplicon size generated from the specimen by PCR correctly predicted the biovars isolated in over 85% of positive specimens. Thus, this PCR test was valuable in allowing early detection of U. urealyticum in neonatal respiratory specimens, as well as in providing biovar information.     

A simple method for evaluating data from an interlaboratory study

The propagation of shear waves in ex vivo tissue samples, agar/gel phantoms, and human volunteers was investigated. A moving coil apparatus was constructed to generate low acoustic frequency shear perturbations of 50 to 400 Hz. Oscillating gradients phase-locked with the shear stimulus were used to generate a series of phase contrast images of the shear waves at different time-points throughout the wave cycle. Quantitative measurements of wave velocity and attenuation were obtained to evaluate the effects of temperature, frequency, and tissue anisotropy. Results of these experiments demonstrate significant variation in shear wave behavior with tissue type, whereas frequency and anisotropic behavior was mixed. Temperature-dependent behavior related mainly to the presence of fat. Propagation velocities ranged from 1 to 5 m/sec, and attenuation coefficients of from 1 to 3 nepers/unit wavelength, depending on tissue type. These results confirm the potential of elastic imaging attributable to the intrinsic variability of elastic properties observed in normal tissue, although some difficulty may be experienced in clinical implementation because of viscous attenuation in fat.     

A simple method for extracting DNA from old skeletal material

Extraction of DNA from old skeletal material is of great importance in the identification of human remains, but is particularly difficult because the methods currently employed, especially those using phenol/chloroform, are not always satisfactory. A simple technique based on the removal of non-nucleic acid material by salting out (precipitation) with saturated sodium acetate is described; the presence of DNA in the extract being confirmed by amplification of selected sequences of the HLA-DRB1 gene using the polymerase chain reaction (PCR). The method was applied to fresh bone (five femoral heads and six vertebral bodies) and to bone from two forensic cases, 3 and 9 months post-mortem, respectively. Parallel extractions using the phenol/chloroform technique were performed on all samples in order to compare the efficiency of the two methods. Using sodium acetate precipitation, amplifiable DNA was consistently extracted from fresh bone, as well as from the two forensic cases. With the phenol/chloroform method, amplification was successful in only 7 out of 11 instances with the fresh bone samples and failed in both forensic cases. The studies also showed that an effective way of removing PCR inhibitors is to subject the extract to agarose gel electrophoresis, isolate the high molecular weight area and re-extract the DNA from the gel by boiling. It was concluded that the sodium acetate method is a valid alternative to established techniques for extracting DNA from bone and that it offers the advantages of being simple, quick, inexpensive and avoids using hazardous reagents.     

A simple plethysmographic method for differentiating primary from secondary varicose veins

Characteristics of venous flow were studied in 81 normal legs and in 98 legs with varicose vein disorders. The change in the volume in the calf after calf muscle contractions was studied using the strain gauge technique with the patients in the erect position. During contractions of the calf muscle, the volume in the calf decreases, chiefly because of reduction of blood volume in the veins. After cessation of the contractions, there is a gradual return of volume to precontraction values. This was measured in seconds and called venous return time and in milliliters times 100 milliliters of tissue-1 times minutes-1 and called venous reflux flow. In normal persons, the venous return time was 21.9+/-6.7 (S.D.) seconds, and in patients with venous disorders, the corresponding time was 6.9+/-2.9 (S.D.) seconds. Venous reflux flow which was inversely correlated with the venous return time was 11.4+/-4.9 and 22.3+/-7.3 (S.D.), respectively. A good correlation was found between venous return time and venous pressure measurements. No age or sex differences were seen. In patients with superficial venous insufficiency, the venous return time and venous reflux time became normal when the diseased portion of the vein was compressed. In patients with insufficient perforating veins or damaged deep vein valves, external compression did not change venous flow characteristics. This indicates that the method can be used preoperatively to differentiate between primary and secondary varicose veins and, thus, influence the type of operation to be performed. The method can easily be applied for clinical purposes.     

A simple method for evaluating cemented carbides

A simple method is proposed whereby meaningful comparisons can be made between the mechanical properties of cermet cutting tool materials. The method is based upon a test originally described by Palmqvist, but includes a procedure for analyzing the data which makes the test much more useful. Thus, it is shown experimentally and analytically that the parameters measured by the Palmqvist test, the crack resistance parameter,W, (which is shown to be linearly related to the critical strain energy release rateG _IC) and the hardness,H, are related by the following expression 1/W=AH-B whereA andB are constants. The significance of this result is that it can be employed to quickly classify experimental carbide/binder combinations according to their potential as cutting tool materials havingboth high hardness and good resistance to impact. Thus, a few simple measurements to establish the constantsA andB appropriate to the carbide/binder combination under investigation allow a ready comparison to be made with another system for which the constants have previously been established.     

A simple histological method differentiating AL-type from AA-type amyloidosis

We previously reported that the purified Na+-translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus is composed of three major subunits, alpha, beta and gamma. NQR operon was sequenced and was found to be composed of 6 structural genes. Among these genes, nqr1, nqr3 and nqr6 were identified to code for alpha-, gamma- and beta-subunits, respectively. The protein products from nqr2, nqr4 and nqr5, however, were not reported. The sequence data predicted that these three proteins are very hydrophobic and may be unusual in mobility and staining on SDS-PAGE. By modifying the detection method of proteins on SDS-PAGE, we could detect all six subunits encoded by NQR operon in the purified NQR complex. The open reading frame of each subunit was identified from its N-terminal amino acid sequence.     

A simple method for "reference range" estimation from routine laboratory data

A simplified method is presented to estimate reference ranges from hospital laboratory data. It is based on a combination of graphical estimation of relative sizes of normal and abnormal populations and the "mode-center" concept in which the mode of the total population centers on the 50% cumulative frequency of the normal population. This method can be applied to determine reference ranges even though the data source contains abnormally high and/or low values. The reference ranges obtained for BUN and calcium from in-patient and out-patient sources by this method were found to be similar to those reported for "healthy" subjects.     

A simple method for the eradication of Legionella pneumophila from potable water systems

In this paper we describe a simple method, noncorrosive to pipes, for the eradication of Legionella pneumophila from potable water systems. This method is based on the systematic purging of the pipe networks with cold water containing 1-1.5 mg residual chlorine/L. In the hot water system, a new pipe bypassing the water heater was installed, whereas in the air conditioning system, the circuit is purged with water from the tap water system. The feasibility of this method was studied in two hotels in which the presence of Legionella was detected despite treatment of the water by the hyperchlorination method. The evolution of the presence of Legionella was studied by culture and polymerase chain reaction. Eighty samples from hotel A and sixty-seven samples from hotel B were analyzed during the time that the eradication method was applied. Our results showed that this method permitted the effective elimination of L. pneumophila after 5 months in hotel A and 7 months in hotel B.     

A simple method for glass insulating tungsten microelectrodes

A method for insulating tungsten wires with glass by collapsing a glass capillary tube around the wire is described. A common laboratory electrode puller can be used. A new method for removing the glass from the tip using hydrofluoric acid is also described.     

A simple method for recovering the motile spermatozoa from extremely low quality sperm samples

Recovery of motile spermatozoa from extremely low quality samples for use in the intracytoplasmic sperm injection (ICSI) procedure is difficult. To solve this problem we developed a simple method to recover the motile spermatozoa using a 3% polyvinylpyrrolidone (PVP) droplet. After depositing a sperm pellet into this slightly viscous droplet, motile spermatozoa readily swam out to the clear area while immotile spermatozoa dispersed to a lesser extent, so that motile and immotile cells became clearly separated from each other. A total of 36 ICSI cycles using spermatozoa with extremely low quality characteristics were performed. We recovered the motile spermatozoa from all sperm samples from two sources of poor quality spermatozoa. Thirty-one cycles of ICSI with ejaculate resulted in fertilization and pregnancy rates of 54 and 29% respectively. Five cycles of ICSI with frozen-thawed epididymal spermatozoa resulted in fertilization and pregnancy rates of 70 and 60% respectively. The 3% PVP droplet method is very simple and easy to perform, so it may be useful for recovering the motile spermatozoa from extremely low quality sperm samples used for ICSI.