Testicular hypertrophy as predictor of contralateral nonpalpable testis among Chinese boys: An 18-year retrospective study.

OBJECTIVE: To assess the accuracy of contralateral testis hypertrophy for predicting the fate of nonpalpable testis in Chinese boys at different ages. METHODS: The data of patients who presented with unilateral impalpable testis and who underwent laparoscopy at the Children's Hospital of Chongqing Medical University between January 1, 2000 and January 1, 2018 were reviewed. The boys were divided into four groups: age-matched volunteers with no testicular abnormalities represented the control group (group I), boys with palpable undescended testis (group II), boys with nonpalpable testis (NPT)/viable testis (VT) (group III), and boys with NPT/non-viable testis (NVT) group (group IV). Scrotal testes were prospectively measured by ultrasonography for volume and size, and diagnostic laparoscopy was performed to determine the state of the cryptorchid testis. RESULTS: The mean contralateral testicular volume and length in the boys with an absent testis was 0.78mL and 17mm compared with 0.67mL and 15mm in the boys with a testis present and 0.63mL and 15mm in the controls, respectively (P<0.05). The predictive accuracy, sensitivity, and specificity for an absent testis were 64.9%, 75%, and 49%, respectively, for volume and 64.2%, 56.3%, and 76.4%, respectively for length at the optimal cutoff value of 0.65mL volume and 16.55mm length. Contralateral testis volume was the most accurate in predicting monorchism in 0-2-year-olds (sensitivity: 75%, specificity: 70%, accuracy: 73.1%) and the contralateral testicular length was most accurate for 4-6-years-old (sensitivity: 68.6%; specificity: 77.8%; accuracy: 72.2%). We also included 29 patients with bilateral undescended testis (UDT) and with unilateral nonpalpable. Cutoff values for testicular volume and length were 0.6mL (sensitivity: 81.8%, specificity: 88.9%, accuracy: 86.2%) and 13.5mm (sensitivity: 63.6%, specificity: 77.8%, accuracy: 77.8%). CONCLUSION: The present results exclusively obtained from laparoscopic exploration suggest that a testis volume of>0.65mL or a testis length of>16.55mm could predict monarchism with an accuracy of about 65%. In younger patients aged 0-2 years and 4-6 years, the overall predictive accuracy increases to about 73% but laparoscopic exploration is still required.

Contributions of suspending medium to electrical impedance of blood.

Blood cells from ten normal subjects, anticoagulated with dried sodium heparin, were washed twice with phosphate-buffered saline (PBS) and resuspended with autologous plasma, serum, serum plus sodium heparin, and PBS. The resistance Rp and capacitance Cm of these suspensions were determined by measuring the impedances at three frequencies 100 kHz, 800 kHz and 1.2 MHz, and found to be dependent on the proteins and electrolytes of the suspending medium. Two suspensions with the same medium resistivity might have different resistances if the contents of the two mediums are different. The fibrinogen, serum proteins, sodium heparin and membrane contributed to Cm by 20%, 14%, 2% and 64%, respectively. For the samples with buffered sodium citrate as anticoagulant and in the haematocrit range 30-60%, the group washed and resuspended with PBS had a consistently decreased Rp and Cm compared to the original group. Sodium heparin seemed to be the best anticoagulant when studying the electrical impedance of blood. The influence of suspending medium might result in part from the altered interfacial polarisation. The results might be useful for understanding the origin of the impedance of blood, and imply that impedance measurement may be an alternative method for screening purposes for diseases that involve abnormal compositions of certain plasma proteins.

Electrical impedance and erythrocyte sedimentation rate (ESR) of blood.

The electrical impedance of blood is primarily determined by plasma resistance Rp, cell interior resistance Ri, and cell membrane capacitance Cm. These impedance parameters were measured for 62 samples with various erythrocyte sedimentation rates (ESR = 1-150 mm/h). A formula for estimating ESR by Rp and Cm was obtained by linear regression as: In (ESR) = 10.16-0.016 x f0, (r = 0.974, P < 0.001), where f0 = 10(9)/(2 pi.Rp100.Cm100) defined as the effective characteristic frequency in kHz, Rp100 = Rp/h in omega cm, Cm100 = Cm/h in pF/cm, h is the haematocrit in decimal. The 95% confidence intervals for the coefficients in the above equation were 9.73 to 10.59 and -0.017 to -0.015. The origin of the association was found reasonable since factors increasing the ESR, i.e., the concentration of some plasma proteins and the size of the blood cells, also elevate the capacitance. The results imply that the impedance measurement might be an alternative method for fast determination of the ESR.

Electrical impedance and haematocrit of human blood with various anticoagulants.

The relationship between the electrical impedance parameters and the haematocrit of normal human blood has been determined at 37 degrees C in the haematocrit range of 20-60% for four types of anticoagulant: ACD, EDTA, sodium heparin and buffered sodium citrate. For plasma resistance Rp and interior resistance R(i), the measured data could be fitted by both the exponential expression and the Maxwell-Fricke expressions, Rp = a/(1-h) + b and R(i) = a/h + b, where a and b are constants and h is the haematocrit expressed as a decimal. The membrane capacitance Cm was found to be directly proportional to the haematocrit and could be normalized to 100% haematocrit by the Fricke formula, C100 = C(m)/(1-rho p/Rp), where rho p is the resistivity of plasma. Observed differences for Rp and C(m) among samples with various anticoagulants indicate that the type of anticoagulant influences the electrical properties of the red cells and the plasma.

Triple-frequency method for measuring blood impedance.

A method was developed for simultaneously measuring plasma resistance, cell interior resistance and cell membrane capacitance of blood. A three-element circuit model for simulating the impedance of blood was evaluated by comparing measured and calculated impedance frequency curves and was found feasible. The values of the three elements of the model could be determined by measuring the impedance amplitudes at three different frequencies. The cell membrane capacitance (Cm) was independent of temperature in the range 25-40 degrees C and was significantly higher for blood with ethylenediaminetetraacetic acid (EDTA) as anticoagulant than that for blood with sodium citrate and acid citrate dextrose (ACD). The Cm value of blood from patients with high erythrocyte sedimentation rate (ESR) was found to be significantly higher than that of blood from patients with low ESR. This suggests that the membrane capacitance might be a potential parameter for clinical applications.

Cardiac-related changes in lung resistivity as a function of frequency and location obtained from EITS images.

ECG-gated electrical impedance tomographic spectroscopy (EITS) measurements of the lungs were taken on seven normal subjects in the frequency range 9.6 kHz to 614.4 kHz. The results show that in late systole the resistivity p' relative to the R-wave (i.e. p' = 1 at the R-wave) decreases consistently within the lung. In addition there arises an increase in p' in early systole towards the periphery of the lung. Frequency behaviour of p' changes with location. At all times after the R-wave, in the centre of the lung p' is higher at higher frequency f whereas in the periphery it is lower at higher f. The principal decrease in p' can be explained by increasing pulmonary blood volume due to cardiac contraction. The early systolic increase is presumably due to venous return to the left atrium locally leading blood output from the right ventricle which is delayed by the windkessel effect. Based on a model taking extracapillary and capillary blood volume increase into account, the change in frequency behaviour of p' is explained by regional variations in extracapillary blood vessel size determining the relative contributions of extracapillary blood volume and capillary blood volume change to p' at a certain frequency.

Modelling of cardiac-related changes in lung resistivity measured with EITS.

Resistivity data from 9.6 kHZ to 1.2 MHz were recorded from eight normal subjects using an electrical impedance tomographic spectroscopy (EITS) system and then averaged to a mean cardiac cycle using the ECG gating technique. The Cole-Cole model, that is, extracellular resistance R connected in parallel with intracellular resistance S and membrane capacitance C in series, with a distribution parameter a, was applied to model the frequency characteristics and to produce parametric images. During systole, SC and RC were found to decrease and FR increase. The changes in R/S were not consistent among the subjects. We estimated the peak changes in R, S and C to be -2.5%, -3.3% and -7.6% respectively. The results can be explained by considering the blood vessels as spheres of different sizes with blood inside them. The decrease in R during systole might be caused by the increased blood content in relatively large vessels, whereas that in S by the increased blood volume in relatively small vessels. The capacitance of blood is normally smaller than that of lung tissue, whereas FR blood is higher than that of lung tissue. Hence, as blood content increases, C should decrease and FR increase.

Quantitative correlations among fibrinogen concentration, sedimentation rate and electrical impedance of blood.

Blood cells from 8 normal subjects, anticoagulated with EDTA, were washed twice with saline solution (100 mmol/l) and resuspended into saline solutions of different concentrations of human plasma fibrinogen. The erythrocyte sedimentation rates (ESRs) of these suspensions were determined by the Westergren method, and their resistance Rp and capacitance Cm were determined by measuring the impedances at three frequencies 100 kHz, 800 kHz and 1.2 MHz. The results showed that the logarithm of the ESR was proportional to the concentration of fibrinogen, Fb (g/l), expressed as: ln(ESR) = 0.468Fb - 0.10, (r = 0.96); and the haematocrit-normalised resistance R'p and capacitance C'm were both directly proportional to the concentration of fibrinogen, R'p = 3.99Fb + 465.0, (r = 0.87), and C'm = 49.7Fb + 628.2, (r = 0.96). The influence of fibrinogen on the impedance might partly be the result of interfacial polarisation and/or of red cell rouleaux formation. The results are useful for understanding the mechanism of the association between the impedance and the ESR of blood, and for finding means of improving the accuracy when estimating the ESR by the electrical impedance method.

Model for the dielectric properties of human lung tissue against frequency and air content.

Electrical impedance tomographic spectroscopy measurements of the lungs are taken from nine normal subjects, in the frequency range 9.6 kHz-1.2 MHz. The results show that resistivity rho'FRC relative to functional residual capacity increases almost linearly with inspiration volume V, with the slope of the curve increasing with frequency f. Resistivity rho'9.6 kHz relative to 9.6 kHz decreases with f. rho'9.6 kHz increases with V, at any given frequency. Curves for rho'9.6 kHz show a roughly linear trend with log10(f). Based on a discussion of the measurement results, a mathematical lung tissue model is designed that involves extra-capillary blood vessels and alveoli, the walls of which consist of blood-filled capillaries, epithelial cells and intercellular liquid. Using this model, the increase in rho'FRC with V is explained by the thinning of alveolar walls with increasing air content. The almost linear shape of curves for rho'9.6 kHz is attributed to four partly overlapping main dispersions caused by extra-capillary blood vessels, epithelial cells, blood and the capillary network.

A rapid method for detection of flavivirus antigens: staphylococcal co-agglutination test using monoclonal antibodies to Japanese encephalitis virus.

Staphylococcus aureus rich in protein A when coated with monoclonal antibodies (MoAb) to Japanese encephalitis virus (JEV) gave a highly specific reaction with flavivirus antigens. The bacteria coated with JEV species-specific MoAb gave a strong co-agglutination with fifty-six JEV isolates from various parts of China, but no co-agglutination with Murray Valley encephalitis (MVE) and Kunjin (Kun) virus antigens. The flavivirus- and subgroup-specific MoAbs were reactive with MVE and Kun, as well as with the majority of the JEV strains. Blocking test with homologous MoAbs abolished co-agglutination further confirming its specificity. Numerous virus particles were observed on the surface of MoAb-coated staphylococci under the electron microscope after co-agglutination. The test appeared rapid, specific, simple to perform, and useful for rapid detection and identification of flaviviruses.

New applications of electrical impedance of human blood.

The electrical impedance parameters of human blood, that is, plasma resistance Rp, cell interior resistance Ri and cell membrane capacitance Cm, were determined by measuring impedance amplitudes at three different frequencies, 0.1, 0.8 and 1.2 MHz. Several new findings have been obtained. The fibrinogen in normal blood raised Rp and Cm by about 4% and 20%, respectively, and serum proteins contributed to the capacitance by about 14%. The results imply that the electrical impedance of blood may reflect certain diseases that involve abnormal compositions of certain plasma proteins. Measurement on 62 samples with various erythrocyte sedimentation rates (ESR) demonstrated that both Rp and Cm were proportional to ESR, implying that the impedance measurement might be an alternative method for quick estimation of ESR. During in vitro storage of blood at 4 degrees C, both Rp and Cm decreased with time, about -20% for Cm after four weeks of storage. The results imply that the impedance change might be a useful index for evaluating the quality of stored blood.

Electrical impedance alterations of red blood cells during storage.

The electrical impedance of blood is determined mainly by the resistance of the plasma (Rp), resistance of the red cell interior fluid (Ri), and capacitance of the cell membranes (Cm). These parameters were measured on 10 stored blood samples consecutively during 4 or 5 weeks of storage at 4 degrees C, once every week. Compared to the values of fresh samples, a statistically significant decrease in Rp was found mainly during the first week of storage, Ri did not decrease significantly until after 3 weeks, whereas Cm decreased progressively with time. These alterations can be explained by known red cell lesions during storage. The results indicate that electrical impedance measurements might be useful for monitoring red cell ageing and assessing the quality of stored red blood cells.

A mouse macrophage-like cell line (MMC-1) and its biological characteristics--scanning electron microscopic observation.

The surface characteristics and EA-rosette with opsonized chicken erythrocytes by mouse macrophage-like cell line (MMC-1) were studied by scanning electron microscopy. The ultrastructure of the cell surface were characteristics of macrophage.

Morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome (HFRS). I. Some peculiar aspects of the morphogenesis of various strains of HFRS virus.

The morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome (HFRS) were studied by thin-section electron microscopy. Ten strains of HFRS virus isolated in China and one strain isolated in Korea were compared. The virions varied in size as well as in the shape and character of their inner components. Both intracellular and extracellular ribosome-like, electron-dense, virus-associated granules were seen. A viral antigen layer was often visualized on the surface of HFRS virus-infected cells, as confirmed by immune electron microscopy. Aberrant tailed particles and elongated rod-like particles were seen infrequently. The morphogenesis of HFRS viruses appears to be more complex than that of other members of the family Bunyaviridae. The prototype Hantaan virus shares a common morphology and morphogenesis with the other HFRS viruses studied.

Identification of Hantaan virus-related structures in kidneys of cadavers with haemorrhagic fever with renal syndrome.

The etiologic agent of haemorrhagic fever with renal syndrome (HFRS), Hantaan virus, was first isolated in 1976. Since then numerous Hantaan-like viruses have been isolated and five serotypes of Hantavirus have been recognized. Serological studies indicate that these viruses are globally distributed, with each serotype occurring in specific areas. Hantaan virus has been intensively studied antigenically, biochemically, and genetically. However there is still a paucity of information on the pathogenesis of Hantaan virus in the human host. In this paper, we report the detection by thin section immune electron microscopy of the occurrence of numerous dense precipitates, typical inclusion bodies, a surface antigen layer, as well as Hantaan virion-like structures in the kidneys of patients that died during the acute phase of HFRS. These findings may shed some light on understanding the pathogenesis of HFRS in target organs most affected by the disease, such as the kidneys.

Morphological evidence for identifying the viruses of hemorrhagic fever with renal syndrome as candidate members of the Bunyaviridae family. Brief report.

Thin section immuno-electron microscopy has been successfully applied to investigate and identify the classical and mild form of HFRS viruses isolated in the People's Republic of China. The results showed that all the 8 strains studied (derived from different parts of China, adapted in different cell lines) share a common morphology and morphogenesis. Essentially, the viruses possess characteristics of members of the Bunyaviridae Family, however, differing by a larger size and size variation and formation of cytoplasmic viral inclusions.