Genetic Interactions Between TRPC6 and NPHS1 Variants Affect Posttransplant Risk of Recurrent Focal Segmental Glomerulosclerosis

Individuals with TRPC6 mutations have variable phenotypes, ranging from healthy carrier to focal segmental glomerulosclerosis (FSGS) leading to renal failure. Here, we describe a family where six members had a novel TRPC6 p.R68W (c.202C>T) mutation, two of whom had renal failure from FSGS, and one had proteinuria. One healthy carrier donated a kidney to her sister. Both donor and recipient had no proteinuria at 20 years posttransplant. Two synonymous NPHS1 polymorphisms, rs2285450 (c.294C>T) and rs437168 (c.2289C>T) segregated with renal failure in this family. These variants had higher allele frequencies in 97 unrelated patients with nephrotic syndrome or FSGS compared to 224 controls. Using patch-clamp experiments in HEK293 and podocytes, we showed that the p.R68W mutation increased TRPC6 current amplitudes, which may be explained by enhanced TRPC6 surface expression. Additionally, while wild-type nephrin suppressed TRPC6 currents, this ability was lost in the presence of NPHS1 c.294C>T polymorphism. When cells were transfected according to combined TRPC6 and NPHS1 genotypes in the family, those representing the donor had lower TRPC6 currents than cells representing the recipient, suggesting that interactions between TRPC6 and NPHS1 variants could possibly account for the variable penetrance of TRPC6 mutations and the absence of recurrence in the graft.

Anamorphic condensing optics for a slitless spectrograph

The use of a slitless spectrograph to obtain the spectra of wakes of hypervelocity projectiles launched in a free flight ballistic range has several advantages. The use of this instrument as a general spectroscopic tool is, however, especially limited for large objects. This is because resolution is determined by final trajectory image size as well as dispersion. The spectral resolution can be improved without altering the desirable properties of the instrument by using an anamorphic system to demagnify the wake image width only. Requirements are given for anamorphic optics used to focus the luminous wakes of hypervelocity projectiles onto the entrance focal plane of a slitless spectrograph. A system currently in use that meets these requirements is described. A comparison of spectra taken with anamorphic and spherical condensing systems is made.

A high gain, time-resolving spectrograph for the diagnosis of laboratory simulated reentry

To increase the sensitivity of a time-resolving spectrograph, a four-stage, magnetically focused, cascade type image intensifier was coupled to an electron scanning image converter. A radiant intensity gain of more than 500, enough to permit the study of far wake radiation, has been achieved, along with sufficient spectral resolution for the determination of temperature and electron density profiles in the flow behind a hypervelocity object. An example of wake temperature results from the time-resolved vibrational bands of CN is presented.

A time-resolving spectrograph for free-flight ballistic range application

Time-resolved spectra for some hypervelocity spheres and cones in a free-flight ballistic range are obtained using a large aperture, slitless spectrograph in conjunction with an image converter camera. For nonablating spheres, only emission from the shock cap can be observed with the present instrument. For ablating models at elevated speeds and range pressures, band systems for such molecular species as C(2), CH, and CN for some objects containing hydrocarbons and Cu(2), CuF, CuO, BeO, and AlO for metallic models have been observed in the near wake region of the flow. The feasibility of using a high gain image intensifier for the study of far wake emission is discussed.

KINETICS OF THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOR

The rates of thermal decomposition of hydrogen peroxide vapor were measured by the static method at low pressures (0.2 to 20 mm. Hg), over the temperature range 300°–600 °C., in carefully cleaned glass vessels. The reaction was of the first order with respect to time and the final products were only water and oxygen. Around 400 °C. the character of the reaction changed gradually from heterogeneous (surface effects, low activation energy) to homogeneous (reproducible rates in various vessels). With initial pressures of about 10 mm. Hg the experimental rates above 400° lead to an apparent activation energy of 43 kcal. and a frequency factor of 1010.7. After correction for the residual surface decomposition, the rate equation becomes[Formula: see text]in good agreement with the accepted value for the O—O bond dissociation energy. The reaction rates increased regularly with pressure.Packing the reaction vessels with glass rods and adding various gases (including nitric oxide and propylene) had no appreciable effect on the gas-phase reaction. Deuterium peroxide vapor decomposed at the same rate as hydrogen peroxide under comparable conditions. The results may be explained adequately by the following non-chain mechanism for the uncatalyzed decomposition:[Formula: see text]

HYDROGEN PEROXIDE: THE LOW TEMPERATURE HEAT CAPACITY OF THE SOLID AND THE THIRD LAW ENTROPY

The heat capacity of crystalline hydrogen peroxide between 12° K. and the melting point has been determined with a low temperature adiabatic calorimeter. The heat of fusion was also measured and found to be 2987 ± 3 cal./mole. The two samples of hydrogen peroxide used were 99.97 mole % pure as deduced from behavior on melting and from premelting heat capacities; the triple point was estimated to be 272.74 K.The only anomaly observed in the heat capacity measurements was the absorption of 1.3 cal./mole at 216.8 ± 0.15° K., the lower eutectic temperature of H2O-H2O2 solutions. Such an effect is to be expected if the only significant impurity is water. The entropy of hydrogen peroxide as an ideal gas at 1 atm. pressure and 25° C. computed from the thermal measurements is 55.76 ± 0.12 cal./mole deg. Comparison of this datum with the recalculated statistical entropy leads to a value of 3.5 kcal./mole for the height of a hypothetical single barrier hindering internal rotation in the molecule. From these results it is concluded that hydrogen peroxide does not consist of two tautomeric modifications.

INFRARED SPECTRUM, MOLECULAR STRUCTURE, AND THERMODYNAMIC FUNCTIONS OF HYDROXYLAMINE

The absorption spectrum of pure hydroxylamine in the vapor and solid states was measured with a prism instrument in the range 1.5–25 µ. Except in one case the fundamental vibrations were clearly outlined and in some instances, particularly the 1115 cm−1 band, the fine structure was resolved well enough for a significant calculation of the rotational constants. From the latter it was possible to confirm, within fairly close limits, the probable structure of the hydroxylamine molecule, a nearly symmetric top of point group Cs. At least two of the bands appeared to be doubled owing, presumably, to existence of a mixture of cis-and trans-forms of the molecule. The O—H and N—H distances have nearly the same value as in water and ammonia respectively and the N—O distance is 1.46 Å.The thermodynamic functions of gaseous hydroxylamine were calculated using the observed fundamental frequencies; some uncertainty accrues from the torsional oscillation. The infrared spectrum of crystalline hydroxylamine hydrochloride was also studied.