Quantification of Renal Stone Contrast with Ultrasound in Human Subjects

Purpose: Greater visual contrast between calculi and tissue would improve ultrasound (US) imaging of urolithiasis and potentially expand clinical use. The color Doppler twinkling artifact has been suggested to provide enhanced contrast of stones compared with brightness mode (B-mode) imaging, but results are variable. This work provides the first quantitative measure of stone contrast in humans for B-mode and color Doppler mode, forming the basis to improve US for the detection of stones. Materials and Methods: Using a research ultrasound system, B-mode imaging was tuned for detecting stones by applying a single transmit angle and reduced signal compression. Stone twinkling with color Doppler was tuned by using low-frequency transmit pulses, longer pulse durations, and a high-pulse repetition frequency. Data were captured from 32 subjects, with 297 B-mode and Doppler images analyzed from 21 subjects exhibiting twinkling signals. The signal to clutter ratio (i.e., stone to background tissue) (SCR) was used to compare the contrast of a stone on B-mode with color Doppler, and the contrast between stone twinkling and blood-flow signals within the kidney. Results: The stone was the brightest object in only 54% of B-mode images and 100% of Doppler images containing stone twinkling. On average, stones were isoechoic with the tissue clutter on B-mode (SCR = 0 dB). Stone twinkling averaged 37 times greater contrast than B-mode (16 dB, p < 0.0001) and 3.5 times greater contrast than blood-flow signals (5.5 dB, p = 0.088). Conclusions: This study provides the first quantitative measure of US stone to tissue contrast in humans. Stone twinkling contrast is significantly greater than the contrast of a stone on B-mode. There was also a trend of stone twinkling signals having greater contrast than blood-flow signals in the kidney. Dedicated optimization of B-mode and color Doppler stone imaging could improve US detection of stones

First-in-human clinical trial of ultrasonic propulsion of kidney stones

PURPOSE: Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcutaneously to reposition kidney stones. We report what are to our knowledge the findings from the first human investigational trial of ultrasonic propulsion toward the applications of expelling small stones and dislodging large obstructing stones. MATERIALS AND METHODS: Subjects underwent ultrasonic propulsion while awake without sedation in clinic, or during ureteroscopy while anesthetized. Ultrasound and a pain questionnaire were completed before, during and after propulsion. The primary outcome was to reposition stones in the collecting system. Secondary outcomes included safety, controllable movement of stones and movement of stones less than 5 mm and 5 mm or greater. Adverse events were assessed weekly for 3 weeks. RESULTS: Kidney stones were repositioned in 14 of 15 subjects. Of the 43 targets 28 (65%) showed some level of movement while 13 (30%) were displaced greater than 3 mm to a new location. Discomfort during the procedure was rare, mild, brief and self-limited. Stones were moved in a controlled direction with more than 30 fragments passed by 4 of the 6 subjects who had previously undergone a lithotripsy procedure. The largest stone moved was 10 mm. One patient experienced pain relief during treatment of a large stone at the ureteropelvic junction. In 4 subjects a seemingly large stone was determined to be a cluster of small passable stones after they were moved. CONCLUSIONS: Ultrasonic propulsion was able to successfully reposition stones and facilitate the passage of fragments in humans. No adverse events were associated with the investigational procedure

Evaluating Hammermill Tip Speed, Air Assist, and Screen Hole Diameter on Ground Corn Characteristics

Whole yellow dent #2 corn was ground using two 43 mm Andritz hammermills (Model: 4330-6, Andritz Feed & Biofuel, Muncy, PA; JBS Live Pork LLC Feed Mill, Fremont, IA). Both mills discharged to a shared plenum where samples were collected via a sample port. Each mill was equipped with 72 hammers and 300 HP motors on a variable frequency drive (VFD). Corn was ground on 3 separate days to create replication and treatments were randomized within replication. Treatments were arranged in a 3 × 3 × 3 factorial design with 3 tip speeds (12,383, 16,323, and 20,263 ft/min); 3 screen hole diameters (6/64, 10/64, and 16/64 in.); and 3 air assist system fan RPM’s (60, 80, and 100% of fan motor load). Samples of each treatment were collected and analyzed for moisture, particle size, and flowability characteristics. Particle size analysis was completed using a 13-sieve stack with the inclusion of sieve agitators and flow agent. Flowability characteristics were evaluated using a composite flow index (CFI), which includes percent compressibility, angle of repose (AoR), and critical orifice diameter (COD). Data were analyzed as a 3 × 3 × 3 factorial using the PROC GLIMMIX procedure of SAS with grinding run as the experimental unit and sample collection day as a blocking factor. There were no 3-way interactions for screen hole diameter × hammer tip speed × air flow for the geometric mean diameter (dgw) or any flowability characteristics of ground corn. There was a 3-way interaction for particle size standard deviation (Sgw), (linear screen hole diameter × linear hammer tip speed × linear air flow, P = 0.029). There was a linear screen hole diameter × linear hammer tip speed interaction (P = 0.001) for dgw. When tip speed increased from 12,383 to 20,263 ft/min, the rate of decrease in dgw was greater as screen hole diameter increased from 6/64 to 16/64 in. An interaction of screen hole diameter and hammer tip speed (linear × linear, P = 0.040) was also observed for the CFI. The CFI results increased with increasing screen hole diameter when corn was ground using a hammer tip speed of 12,383 ft/min but no differences were observed as tip speed increased to 16,323 and 20,263 ft/min. An interaction of screen hole diameter and hammer tip speed (quadratic × quadratic, P = 0.001) was observed for mill motor load. Mill motor load decreased as screen hole diameter increased from 6/64 in. to 16/64 in., but increased as hammer tip speed was increased with the most significant reductions being observed as tip speed increased from 12,383 ft/min to 16,323 ft/min on the 6/64 in. screen. In conclusion, hammer tip speed and air flow rate are viable options for adjusting ground material characteristics when grinding using a hammermill, alongside the traditional screen variations. Along with the range of particle sizes capable of being produced, an increased level of accuracy can also be achieved with hammer tip speed and air flow adjustments with minimal down time necessary for screen changes

Genomic and expression analysis of multiple Sry loci from a single Rattus norvegicus Y chromosome

BACKGROUND: Sry is a gene known to be essential for testis determination but is also transcribed in adult male tissues. The laboratory rat, Rattus norvegicus, has multiple Y chromosome copies of Sry while most mammals have only a single copy. DNA sequence comparisons with other rodents with multiple Sry copies are inconsistent in divergence patterns and functionality of the multiple copies. To address hypotheses of divergence, gene conversion and functional constraints, we sequenced Sry loci from a single R. norvegicus Y chromosome from the Spontaneously Hypertensive Rat strain (SHR) and analyzed DNA sequences for homology among copies. Next, to determine whether all copies of Sry are expressed, we developed a modification of the fluorescent marked capillary electrophoresis method to generate three different sized amplification products to identify Sry copies. We applied this fragment analysis method to both genomic DNA and cDNA prepared from mRNA from testis and adrenal gland of adult male rats. RESULTS: Y chromosome fragments were amplified and sequenced using primers that included the entire Sry coding region and flanking sequences. The analysis of these sequences identified six Sry loci on the Y chromosome. These are paralogous copies consistent with a single phylogeny and the divergence between any two copies is less than 2%. All copies have a conserved reading frame and amino acid sequence consistent with function. Fragment analysis of genomic DNA showed close approximations of experimental with predicted values, validating the use of this method to identify proportions of each copy. Using the fragment analysis procedure with cDNA samples showed the Sry copies expressed were significantly different from the genomic distribution (testis p < 0.001, adrenal gland p < 0.001), and the testis and adrenal copy distribution in the transcripts were also significantly different from each other (p < 0.001). Total Sry transcript expression, analyzed by real-time PCR, showed significantly higher levels of Sry in testis than adrenal gland (p, 0.001). CONCLUSION: The SHR Y chromosome contains at least 6 full length copies of the Sry gene. These copies have a conserved coding region and conserved amino acid sequence. The pattern of divergence is not consistent with gene conversion as the mechanism for this conservation. Expression studies show multiple copies expressed in the adult male testis and adrenal glands, with tissue specific differences in expression patterns. Both the DNA sequence analysis and RNA transcript expression analysis are consistent with more than one copy having function and selection preventing divergence although we have no functional evidence

Update on clinical trials of kidney stone repositioning and preclinical results of stone breaking with one system

Our goal is an office-based, handheld ultrasound system to target, detach, break, and/or expel stones and stone fragments from the urinary collecting system to facilitate natural clearance. Repositioning of stones in humans (maximum 2.5 MPa, and 3-second bursts) and breaking of stones in a porcine model (maximum 50 cycles, 20 Hz repetition, 30 minutes, and 7 MPa peak negative pressure) have been demonstrated using the same 350-kHz probe. Repositioning in humans was conducted during surgery with a ureteroscope in the kidney to film stone movement. Independent video review confirmed stone movements (≥ 3 mm) in 15 of 16 kidneys (94%). No serious or unanticipated adverse events were reported. Experiments of burst wave lithotripsy (BWL) effectiveness on breaking human stones implanted in the porcine bladder and kidney demonstrated fragmentation of 8 of 8 stones on post mortem dissection. A 1-week survival study with the BWL exposures and 10 specific-pathogen-free pigs, showed all findings were within normal limits on clinical pathology, hematology, and urinalysis. These results demonstrate that repositioning of stones with ultrasonic propulsion and breaking of stones with BWL are safe and effective

Cutting edge: NKG2C(hi)CD57+ NK cells respond specifically to acute infection with cytomegalovirus and not Epstein-Barr virus.

CMV induces the expansion of a unique subset of human NK cells expressing high levels of the activating CD94-NKG2C receptor that persist after control of the infection. We investigated whether this subset is CMV specific or is also responsive to acute infection with EBV. We describe a longitudinal study of CMV(-) and CMV(+) students who were acutely infected with EBV. The NKG2C(hi) NK subset was not expanded by EBV infection. However, EBV infection caused a decrease in the absolute number of immature CD56(bright)CD16(-) NK cells in the blood and, in CMV(+) individuals, induced an increased frequency of mature CD56(dim)NKG2A(+)CD57(+) NK cells in the blood that persisted into latency. These results provide further evidence that NKG2C(+) NK cells are CMV specific and suggest that EBV infection alters the repertoire of NK cells in the blood

Cutting edge: NKG2C(hi)CD57+ NK cells respond specifically to acute infection with cytomegalovirus and not Epstein-Barr virus.

CMV induces the expansion of a unique subset of human NK cells expressing high levels of the activating CD94-NKG2C receptor that persist after control of the infection. We investigated whether this subset is CMV specific or is also responsive to acute infection with EBV. We describe a longitudinal study of CMV(-) and CMV(+) students who were acutely infected with EBV. The NKG2C(hi) NK subset was not expanded by EBV infection. However, EBV infection caused a decrease in the absolute number of immature CD56(bright)CD16(-) NK cells in the blood and, in CMV(+) individuals, induced an increased frequency of mature CD56(dim)NKG2A(+)CD57(+) NK cells in the blood that persisted into latency. These results provide further evidence that NKG2C(+) NK cells are CMV specific and suggest that EBV infection alters the repertoire of NK cells in the blood