A Clinically Feasible Electrode Array for 3D Intraoperative Electrical Impedance Tomography-Based Surgical Margin Assessment in Robot-Assisted Radical Prostatectomy.

OBJECTIVE: A novel small form factor circular electrode array was designed specifically for electrical impedance tomography (EIT) based assessment of surgical margins during robot assisted radical prostatectomy (RARP). METHODS: The electrode array consists of 33 gold-plated electrodes arranged within a 9.5 mm diameter circular footprint on the end of a surgical probe that can be introduced through a standard 12 mm laparoscopic port used during RARP. The electrode array contains 8 larger, low-contact impedance outer electrodes dedicated for current drive and an internal grid of 25 smaller electrodes for simultaneous voltage measurement. Separating electrode geometry by function is designed to improve current delivery, speed, and resolution while reducing hardware requirements. RESULTS: Simulations demonstrated that 1 mm diameter hemispherical prostate cancer inclusions could be localized within regions of adipose and benign prostate tissue; 1.5 mm diameter inclusions were required for localization within muscle tissue. A 2.38 mm diameter aluminum rod in 0.2 S/m saline could be localized throughout the imaging domain with a position error of less than 2.5 mm for depths from the electrode array surface of up to 1.7 mm. Ex vivo tissue experiments with a bovine model demonstrate visual congruence of muscle and adipose tissue locations between the sample and reconstructed images. CONCLUSION: Simulation and experimental results indicate good detection and location of inclusions. SIGNIFICANCE: These results suggest the proposed electrode array design can provide sufficient accuracy in the detection and localization of prostate cancer against clinically relevant background tissues for use during RARP.

Towards intraoperative surgical margin assessment: Validation of an electrical impedance-based probe with ex vivo bovine tissue.

Radical prostatectomy (RP) is a common surgical therapy to treat prostate cancer. The procedure has a high positive surgical margin (PSM) rate ranging from 4-48%. Patients with PSMs have a higher rate of cancer recurrence and often undergo noxious adjuvant therapy. Intraoperative surgical margin assessment (SMA) with an electrical impedance-based probe can potentially identify PSMs in real-time. This would enable surgeons to make data-based decisions in the operating room to improve patient outcomes. This paper focuses on characterizing an impedance sensing SMA probe with specialized electrodes to improve speed and bandwidth while maintaining accuracy. 3D electrical impedance tomography (EIT) reconstructions were generated from ex vivo bovine tissue to characterize probe imaging and to determine an optimal applied pressure range (15 Pa to 38 Pa). Classification accuracy of adipose and muscle tissue was evaluated by comparing the experimental data set to simulated data based on a ground truth binary map of the tissue. Experimental AUCs ≥0.83 were maintained up to 50 kHz. The developed impedance sensing probe successfully classified between muscle and adipose tissue in an ex vivo bovine model. Future work includes improving performance of the SMA probe with custom hardware and collecting data from ex vivo and in vivo prostatic tissues.Clinical Relevance-This technology is expected to reduce the rate of PSMs in RP and decrease the use of post-surgical adjuvant therapies. It is also anticipated that intraoperative impedance measurements will increase efficacy of nerve sparing procedures and reduce complications such as incontinence and erectile dysfunction.

Role of beta1- and beta3-adrenoceptors in the regulation of lipolysis and thermogenesis in rat brown adipocytes.

To evaluate the physiological functions of beta1-, beta2-, and beta3-adrenoceptors (ARs) in brown adipose tissue, the lipolytic and respiratory effects of various adrenergic agonists and antagonists were studied in rat brown adipocytes. The beta-agonists stimulated both lipolysis and respiration (8-10 times above basal levels), with the following order of potency (concentration eliciting 50% of maximum response): CL-316243 (beta3) > BRL-37344 (beta3) > isoproterenol (mainly beta1/beta2) > norepinephrine (NE; mainly beta1/beta2) > epinephrine (mainly beta1/beta2) >> dobutamine (beta1) >> procaterol (beta2). Schild plot coefficients of competitive inhibition experiments using ICI-89406 (beta1 antagonist) revealed that more than one type of receptor mediates NE action. It is concluded from our results that 1) NE, at low plasma levels (1-25 nM), stimulates lipolysis and respiration mainly through beta1-ARs, 2) NE, at higher levels, stimulates lipolysis and respiration via both beta1- and beta3-ARs, 3) beta2-ARs play only a minor role, and 4) beta3-ARs may represent the physiological receptors for the high NE concentrations in the synaptic cleft, where the high-affinity beta1-ARs are presumably desensitized. It is also suggested that lipolysis represents the flux-generating step regulating mitochondrial respiration.

Beta 3-adrenoceptor in guinea pig brown and white adipocytes: low expression and lack of function.

In the guinea pig, cold acclimation induced a conversion of unilocular to multilocular adipocytes in interscapular (IS) and retroperitoneal (RP) fat depots but not in the epididymal (EP) fat pad. The conversion was associated with an increase in mitochondriogenesis and the appearance of the uncoupling protein. The maximal lipolytic responses to norepinephrine and dibutyryl adenosine 3',5'-cyclic monophosphate were decreased in IS cells, unchanged in RP cells, and increased in EP cells, suggesting a site-specific regulation of lipolysis at the postreceptor level. beta 3-Adrenergic agonists were not lipolytic regardless of the depot and the thermal environment of the animal. These agents did not inhibit glucose transport and lipogenesis, as was previously reported for rodents. Cloning and sequencing of the guinea pig beta 3-adrenoceptor gene revealed a slightly higher amino acid sequence similarity with the human than with the rodent beta 3-adrenoceptors. beta 3-Adrenoceptor transcripts were present at a very low level in guinea pig adipocytes, and mRNA levels did not increase to a significant extent after cold acclimation. The guinea pig thus differs from rodents by an absence of beta 3-adrenergic effects and by low beta 3-adrenoceptor expression in brown and white adipose tissues.

The effect of alternative economic and genetic covariation structures on the relative economic gain from selection using stayability traits.

Three alternative cost ratios and the ratio of annual fixed cost for cows to net replacement cost for three populations that differed in genetic (co)variances were investigated. We studied their effect on the value of longevity records to supplement production records to achieve genetic gains for reducing the nonfeed cost of producing a unit of milk. Data files were constructed from stochastically generated production records and culling variant records; the later records represented the relative value for cow survival of all nonproduction traits. The use of one stayability trait instead of none increased gain by 1 to 9% across the populations and cost ratios. Only 2% additional gain occurred with two stayability traits instead of one. Populations that differed in genetic correlation between production and the survival value of nonproduction traits and in survival heritabilities contributed 2 to 5% toward the greater gains. The different cost ratios contributed 1 to 3%. The effect of increasing the length of herd life independent of production is inherently secondary to the effect of increasing the production during lactation. If genetic antagonism between production and the survival of nonproduction traits is found and if the net replacement costs are high, the use of production and longevity records for selection can enhance gain by up to 10%.

Characterization of beta 1- and beta 3-adrenoceptors in intact brown adipocytes of the rat.

1. The binding properties of beta 1-, beta 2- and beta 3-adrenoceptors were determined in isolated brown adipocytes of the rat rather than in membrane preparations from tissue homogenates, because typical brown adipocytes represent only about 40% of the various cells present in brown adipose tissue. Binding characteristics were assessed with the hydrophilic beta-adrenoceptor radioligand, (-)-[3H]-CGP 12177. The potent beta-antagonist, bupranolol (100 microM) was used to determine nonspecific binding. Characterization was essentially performed by saturation and competition studies. 2. The saturation curve of (-)-[3H]-CGP 12177 was clearly biphasic (Hill coefficient, nH = 0.57 +/- 0.11, P < 0.01) indicating the presence of two different beta-adrenoceptor populations of high (KD = 0.24 +/- 0.04 nM) and low (KD = 80 +/- 7 nM) affinity. The low affinity sites were more numerous (Bmax = 121,000 +/- 30,000 sites/cell) than the high affinity sites (Bmax = 12,000 +/- 1,000 sites/cell). 3. (-)-[3H]-CGP 12177 (25 nM) was displaced by adrenaline (Ad), noradrenaline (NA), isoprenaline (Iso), phenylephrine (Phe) and by the new beta 3 agonist, CL 316,243 (CL) in a biphasic pattern. The order of potency for (-)-[3H]-CGP 12177 displacement from the small population of high affinity sites (Iso >> NA > Ad >> CL >> Phe was in agreement with a beta 1/beta 2-classification. In contrast, the potencies of the same agonists for displacing the radioligand from the low affinity binding sites (CL >> Iso > NA > Ad >> Phe) revealed the presence of a distinct population of adrenoceptors obeying a beta 3-classification. 5-HT did not displace (-)-[3H]-CGP 12177 (25 nM) when used at concentrations as high as 0.1 mM.4. The beta-adrenoceptor antagonist, (-)-bupranolol, was more effective than (-)-propranolol for displacing(- )-[3H]-CGP 12177 (25 nM) from the high (Ki= 0.029 =/- 0.011 and 0.19 +/- 0.07 nM, respectively and low (Ki= 0.27 +/- 0.04 microM and 1.6 +/- 0.2 lM, respectively) affinity binding sites. The selective beta 1 antagonist CGP 20712A efficiently displaced the radioligand from a small population (Ki = 65 +/- 19 pM)of binding sites, confirming the presence of beta 1-adrenoceptors.5. To evaluate whether beta 2-adrenoceptors could be identified in the population of high affinity binding sites, displacement studies were performed at a low concentration of (- )-[3H]-CGP 12177 (4 nM) that mainly labelled beta 1/beta 2-adrenoceptors. ICI 118 551 ( a selective beta 2-antagonist) and procaterol (a selective beta 2-agonist) displaced (- )-[3H]-CGP 12177 from its binding sites with very low affinity (Ki = 0.17 +/- 0.02 micro M and Ki = 11 +/- 2 micro M respectively).6. From these observations, we conclude that: (1) two kinds of binding sites with low and high affinities for (-)-[H]-CGP 12177 can be detected in intact brown adipocytes, (2) there are 10 times more low than high affinity beta-adrenoceptors, as determined by saturation or competition curve analysis, (3) the high affinity binding sites mainly correspond to beta1-adrenoceptors, whereas the low affinity sites represent beta 3-adrenoceptors, and (4) beta 2-adrenoceptors are undetectable.7. It is suggested that the low affinity beta 3-adrenoceptors represent the physiological receptors for noradrenaline secreted from sympathetic nerve endings when the concentration of the neurohormone in the synaptic cleft is very high and/or when the high affinity beta 1-adrenoceptors are desensitized by prolonged sympathetic stimulation such as chronic cold exposure.

Comparison of the lipolytic effects of norepinephrine and BRL 37344 in rat brown and white adipocytes.

The lipolytic effects of norepinephrine (a non-selective beta-agonist) and BRL 37344 (a selective beta3-agonist) were compared in isolated rat brown and white adipocytes. Norepinephrine and BRL 37344 maximally stimulated lipolysis in brown and white adipocytes, approximately 10 times above basal values. However, adipocyte sensitivity for BRL 37344 was greater than that for norepinephrine, particularly in brown adipocytes [the EC50 values (nM) for BRL 37344 and norepinephrine were 5 +/- 1 and 103 +/- 31 in brown adipocytes (P < 0.01) versus 56 +/- 9 and 124 +/- 17 in white adipocytes (P < 0.05), respectively]. On the other hand, the lipolytic effects of norepinephrine were totally blocked by 20-40 times superior concentrations of propranolol or bupranolol in brown as well as in white adipocytes. In contrast, the lipolytic effects of BRL 37344 were fully inhibited by concentrations of propranolol or bupranolol that were 200-1000 superior to the beta3 agonist concentration. The results demonstrate that: (1) the beta3-agonist BRL 37344 is as effective as norepinephrine for maximally stimulating lipolysis in rat brown and white adipocytes, (2) both adipocyte types are more sensitive to the lipolytic effects of BRL 37344 than to those of norepinephrine, (3) although bupranolol is a better antagonist than propranolol on BRL 37344-stimulated lipolysis, it cannot be considered as a specific beta3-antagonist, (4) brown adipocytes are 10 times more sensitive than white adipocytes to the lipolytic effects of BRL 37344, suggesting an important role of beta3-receptors in brown adipose tissue.

[The bovine zona pellucida: differences in macromolecular composition between oocytes, pre-treated with A-23187 or not, and embryos]. / La zone pellucide bovine: différences de composition macromoléculaire entre ovocytes, prétraités ou non à l'A 23187, et embryons.

The SDS-PAGE method was used to determine the composition of isolated bovine zona pellucida (ZP). This egg extracellular coat appears to be characterized by 3 major glycoproteins (ZP1, ZP2, ZP3), with apparent molecular weight (MW) of 80-70 kD, 66-63 kD and 60 kD, respectively, as revealed by 1-dimensional SDS-PAGE. After 2-dimensional SDS-PAGE, the zona pellucida electrophoretic pattern indicates a fourth glycoprotein, thus called ZP4. SDS-PAGE analysis of ZP isolated from oocytes and embryos after transit through the genital tract of A23187 pretreated oocytes allowed the description of modifications in glycoproteinic composition.

Genetic value of herd life adjusted for milk production.

Cow herd life adjusted for lactational milk production was investigated as a genetic trait in the breeding objective. Under a simple model, the relative economic weight of milk to adjusted herd life on a per genetic standard deviation basis was equal to CVY/dCVL where CVY and CVL are the genetic coefficients of variation of milk production and adjusted herd life, respectively, and d is the depreciation per year per cow divided by the total fixed costs per year per cow. The relative economic value of milk to adjusted herd life at the prices and parameters for North America was about 3.2. An increase of 100-kg milk was equivalent to 2.2 mo of adjusted herd life. Three to 7% lower economic gain is expected when only improved milk production is sought compared with a breeding objective that included both production and adjusted herd life for relative value changed +/- 20%. A favorable economic gain to cost ratio probably exists for herd life used as a genetic trait to supplement milk in the breeding objective. Cow survival records are inexpensive, and herd life evaluations from such records may not extend the generation interval when such an evaluation is used in bull sire selection.

Relationships of first lactation milk and type traits to cow survival and a sire index for discounted total milk.

The probability of cow survival during each of six consecutive 13-mo periods after first calving was regressed on lactation milk yield and 15 type traits, each recorded during the first lactation. Adjusted coefficients of determination were small (.028 to .081). The ratio of variance in predicted cow survival probabilities due to milk only with that due to the 15 type traits was 12.6:1, 4.7:1, 2.5:1, .5:1, 0:1, and .02:1 for respective herdlife periods. Maximum effect of type traits on herdlife ranged from 11 to 109 d. Prediction equations for cow survival were incorporated into a sire index for discounted total milk yield of progeny. Type traits affected the sire index by their influence on the six predicted survival rates. Milk yield affected the discounted total milk index directly as well as through the survival rates. Simulated variation from milk estimated transmitting abilities for sires accounted for 99.9% of the total variation in the discounted total milk index. Since the effect of the type traits on cow survival rates was greatest during the later herdlife periods, too few animals would have survived to these later periods to reveal any significant effect from type on the discounted total milk index.

Association of bovine lymphocyte antigens with milk fat percentage differences.

A group of 246 Holstein artificial insemination bulls was examined for associations of bovine lymphocyte antigens with differences in transmitting ability for milk and fat yield and fat percent. The mean fat percentage associated with the w10 allele was .15% greater than the mean for four other alleles. No differences in phenotypic or allelic effects were detected for milk or fat yield.

Genetic parameters and environmental factors associated with type traits scored on an ordered scale during first lactation.

Sixty subjective and linearized type data were recorded on 7375 first lactation Holstein cows. Data were analyzed by paternal half-sister analysis for genetic parameters. One hundred and six sires were represented. Two kinds of heritability estimates were obtained; the first was a method 3-derived estimate for the raw scale and the second was a "nonlinear method 3"-derived estimate for an underlying scale. Whenever estimates of heritability on the raw scale were positive, larger estimates were generally obtained on the underlying scale. Some udder traits (e.g., depth, rear length, rear balance, teat placement, rear teat length, rear width) had underlying heritabilities between 10 to 30%. Suspensory strength and teat shape had no genetic variation. Of feet and leg traits only set (.14) and cleanness of hocks (.09) had heritabilities above 6%. Some functional traits (milking speed, edema) had heritabilities near 11%. Disposition, mastitis score, and milk letdown had no genetic variation. Most body traits (e.g., pin and hip width, length and levelness of rump, rib spring) had heritabilities between 15 and 30%. Method 3 phenotypic and genetic correlations relations were computed for the raw scale. Most phenotypic correlations were near zero. Traits associated with size or skeletal dimension had positive phenotypic typic and genetic correlations. Fore udder length, rear udder width, and rear udder height had positive genetic correlations (range .21 to .43). Udder depth had moderate genetic correlations with most udder traits, teat traits and body traits. The statistical models included describer, stage of lactation, and calendar month of description effects. In general, describer effects were the largest and most significant kind of environmental effect. Stage of lactation effects occasionally showed consistent trends. Month effects appeared to be unpredictable.

Mate selection by selection index theory.

Mate selection by selection index prediction of total merit in expected progeny is proposed as a rational basis for making recommendations in the choice of a bull to which a cow may be mated. Growth in USA of service programs recommending bulls to particular cows has motivated the need to rationalize mate selection processes. This paper illustrates that mate selection on the basis of highest index value for expected progeny among potential mates can justify special mate selection programs, when a nonlinear relationship exists between at least one trait in the index and merit.

Heritability of a linear combination of traits.

The heritability, h I (2) , of a linear combination of phenotypes, I, when defined as the ratio of the variance of the genetic index, σ g⋆ (2) *, to the variance of the index, σ I (2) , is shown to be different from the square of the correlation, r HI (2) , between the index and an arbitrary linear combination of genetic effects, H. The gain in H fror selection on I is shown to be proportional to h I (2) . bHg⋆ for any index.