Multi-frequency detection of a dielectric object using flexible contactless RF sensors for tissue diagnosis

The aim of this paper is to experimentally assess the capacity of radio-frequency flexible sensors to localize a dielectric object inside a fluid, which could be used as a non contact sensor detected to the detection or the monitoring a local modification of a tissue, such as a tumor or a lesion. The used sensor is an MRI-like antenna, which consists in a flat, flexible and low cost multi-turn split resonator (MTLR), which features a geometrically pre-determined resonance frequency. The MTLR is used here as a transmit and receive sensor monitored by a distant loop coil. The complex impedance changes observed at the ends of the monitoring coil is known to be linked to the dielectric properties of the resonator environment. If a dielectric object is placed close to the resonator, the complex impedance is altered. In this work, an experimental set up is used to assess the relevance of such a measurement scheme to detect the presence of a dielectric inclusion embedded in another dielectric medium. The setup includes a spherical object of 1.5 cm diameter filled with various NaCl solutions moved vertically inside a tank filled with deionized water by means of a three axis robotic arm, to create an electrical conductivity contrast between the inclusion and the media, and three 2 cm diameter MTLR sensors featuring 30, 47 and 70 MHz resonance frequencies, respectively. The sensors are operated through the use of monitoring coils connected to a network analyzer, and measurements are carried out at each position of the spherical object. The resulting sensor responses are plotted and used for the assessment of sensor performances. In addition, a method to combine the multi-frequency data provided by the three different sensors is proposed. Two different metrics regarding the spatial resolution (SR) and the peak signal to noise ratio (PSNR) are computed to characterize the single sensor performances, as well as the enhancement provided by the proposed multi-frequency approach.

Imaging of a dielectric inclusion using a contactless radio-frequency inductive probe for tissue diagnosis

In this paper, a contactless radio-frequency (RF) inductive probe is used to spatially localize and characterize a complex dielectric organic inclusion in a fluid. The effect of dielectric properties (DP) of this organic material is investigated experimentally and by numerical computations.The used RF probe is a 135 MHz 3 cm diameter and 10 cm long, cylindrical bracelet resonator, placed close to a water tank filled with deionized water which includes a 1.5 cm diameter inclusion filled of air or NaCl solutions and placed in arbitrary positions. The water tank and the inclusion are used to model an organic material including a tumor. The RF probe is used as a transmit and receive sensor. It induces a magnetic field inside the water tank, which, by reciprocity, conveys information about the DP of the investigated material. The impedance changes at the end of the RF probe are directly related to the modifications of the magnetic field, and are measured by means of a network analyzer. A complex fit of the impedance frequency response around the resonance frequency gives access to two quantities proportional to the electrical conductivity and dielectric constant of the inclusion. The inclusion is moved into the water tank along the three axes by means of a robotic arm, so that two three dimensional maps of the equivalent dielectric quantities in function of the inclusion position are sensed by the probe. Then, the inclusion is filled with different conductive NaCl solutions from 0.1 to 1.1 S/m in order to test the ability of the probe to sense the modifications of the dielectric properties of the inclusion. Experimental as well as computation results obtained using the Distributed Point Source Method (DPSM) validate the ability of the proposed probe to localize the inclusion as deep as 1 cm into the water, and the ability of the probe to sense the dielectric property changes of the inclusion.

Protein (lysine) restriction in primiparous lactating sows: effects on metabolic state, somatotropic axis, and reproductive performance after weaning

Low protein intake during lactation has been demonstrated to increase the loss of body protein and to reduce the reproductive performance of female pigs. The objectives of the current experiment were 1) to determine whether protein (lysine) restriction alters levels of somatotropic hormones, insulin, follicle-stimulating hormone, and leptin around weaning, and 2) to evaluate the relationships between these eventual alterations and postweaning reproductive performance. One day after farrowing, crossbred primiparous sows were randomly allocated to one of two diets containing 20% crude protein and 1.08% lysine (C, n = 12) or 10% crude protein and 0.50% lysine (L, n = 14) during a 28-d lactation. Diets provided similar amounts of metabolizable energy (3.1 Mcal/kg). Feed allowance was restricted to 4.2 kg/d throughout lactation, and litter size was standardized to 10 per sow within 5 d after farrowing. Catheters were fitted in the jugular vein of 21 sows around d 22 of lactation. Serial blood samples were collected 1 d before (day W - 1) and 1 d after (day W + 1) weaning, and single blood samples were collected daily from weaning until d 6 postweaning (day W + 6). Sows were monitored for estrus and inseminated. They were slaughtered at d 30 of gestation. During lactation, litter weight gain was similar among treatment groups. Reduced protein intake increased (P < 0.001) sow weight loss (-30 vs -19 kg) and estimated protein mobilization throughout lactation (-4.1 vs -2.0 kg). On day W - 1, L sows had higher (P < 0.02) plasma glutamine and alanine concentrations, but lower (P < 0.05) plasma tryptophan and urea than C sows. Mean and basal plasma GH were higher (P < 0.001), whereas plasma IGF-I and mean insulin were lower in L than in C sows on day W - 1. Preprandial leptin did not differ between treatments on day W - 1, but was higher (P < 0.01) in L sows than in C sows on day W + 1. Mean FSH concentrations were similar in both treatments on day W - 1 (1.3 ng/mL), but L sows had greater (P < 0.001) mean FSH on day W + 1 than C sows (1.6 vs 1.2 ng/mL). The weaning-to-estrus interval (5 +/- 1 d) was similar in both groups. Ovulation rate was lower in L than in C sows (20.0 +/- 1 vs 23.4 +/- 1, P < 0.05). No obvious relationships between reproductive traits and metabolic hormone data were observed. In conclusion, these results provide evidence that protein (lysine) restriction throughout lactation alters circulating concentrations of somatotropic hormones and insulin at the end of lactation and has a negative impact on postweaning ovulation rate.

Influence of insulin treatment and feed restriction on follicular development in cyclic gilts

Crossbred gilts were used to investigate whether exogenous insulin can restore normal follicular growth in feed-restricted gilts. After an 18-day altrenogest treatment, the first day of oestrous behaviour was designed as day 0. From day 0 to 13, all gilts received the same amount of feed, calculated to meet 200% of the energy requirements for maintenance. On day 14, luteolysis was induced by injection of an analogue of prostaglandin F2alpha. All gilts were slaughtered on day 19 and their ovaries removed. In Experiment 1, gilts received a high (240% of maintenance) or low (80%) level of feeding (n=10/group) from day 14 to 18. The number of large follicles (> or = 5 mm) on day 19 was reduced in feed-restricted gilts (16.9 versus 20.6, P<0.05). The same protocol of feed restriction was used in Experiment 2 (240% versus 80% of maintenance from day 14 to 18), and some gilts received daily injections of insulin (0.6 IU live weight kg(-1)). The three experimental groups were H: 240% and no insulin (n=8); H-I: 240%+insulin (n=8) and L-I: 80%+insulin (n=7). On day 18, 4 h after insulin injection, plasma insulin was higher in insulin-treated than in untreated gilts and glucose concentrations were reduced more dramatically in L-I than in H-I gilts (P<0.05). Concentrations of IGF-I were lower in L-I than in other gilts (P<0.05) and plasma IGFBPs were not significantly affected by treatments. On day 19, the number of large follicles (> or = 5 mm) was not significantly influenced by treatments (19.4, 17.6 and 15.3 for H, H-I and L-I gilts, respectively). Insulin, IGF-I and IGFBP-2 levels in follicular fluids from large follicles did not differ between females whereas IGFBP-3 levels were lower in L-I than in H gilts (P<0.05) and intermediate in H-I gilts. Intrafollicular levels of glucose were higher in feed-restricted than in well-fed gilts (P<0.05). These results suggest that exogenous insulin does not restore final follicular growth impaired by acute undernutrition.

Feed restriction in cyclic gilts: gonadotrophin-independent effects on follicular growth

Our objective was to determine whether changes in metabolic hormones, induced by feed restriction, can alter follicle distribution in swine ovaries through effects independent of LH pulsatility. In a factorial arrangement, 24 gilts were fed a high or a low level of dietary energy (240 or 80% of maintenance requirements) and given an antagonist of GnRH or saline between days 3 and 12 of the oestrous cycle. Serial blood samples were collected on day 12 and ovaries on day 13. Antagonist treatment, that blocked LH pulsatility, decreased the number of follicles larger than 2 mm and increased the number of follicles smaller than 1 mm. The feed restriction did not alter gonadotrophin secretion, decreased the number of follicles smaller than 1 mm and increased the number of 1 - to 1.9-mm follicles. These findings indicate that feed restriction can alter the growth of small follicles independently of gonadotrophin levels.

Influence of feed restriction in primiparous lactating sows on body condition and metabolic parameters

Twenty-four primiparous sows were allocated at farrowing to a high (H: 5.5-6 kg feed/day) or a low (L: 2.5-3 kg/day) level of feeding. Litters (8-10 piglets) were weaned at 28+/-2 days. Serial blood samples were collected 1 day before weaning (W-1), in the hours following weaning (W) and 1 day after (W + 1). L sows lost significantly more weight (38 versus 15 kg) and backfat (5.3 versus 2.3 mm) during lactation than H sows. On day W-1, L sows had higher mean concentrations of NEFA (P < 0.01) and GH (P < 0.1 ) and lower concentrations of insulin and IGF-I (P < 0.05) than H sows. Mean concentrations of glucose and cortisol did not differ between groups of sows. On day W + 1, these parameters were not different between treatments, except IGF-I concentrations which remained lower in L than in H sows (P < 0.05). We conclude that lactating primiparous sows alter secretion of metabolic hormones to favour mobilization of body reserves to support milk production. Low insulin and IGF-I may be involved in reduced ovarian activity at and after weaning, through LH-dependent and independent pathways.

Influence of feed restriction during lactation on gonadotropic hormones and ovarian development in primiparous sows

Effects of nutritional deficit during lactation on secretion of gonadotropic hormones and ovarian follicular populations around weaning were investigated in 24 primiparous crossbred sows. Sows were allocated to receive close to ad libitum intakes (H) or approximately 50% of this amount (L) during a 28-d lactation. Serial blood samples were collected 1 d before weaning (W-1), in the hours following weaning (W), and 1 d after (W+1). Their ovaries were removed on the day of weaning or 2 d later (W+2) and subjected to macroscopic and histological observations. Mean and basal LH concentrations were not influenced by the level of feeding. Frequency of LH pulses was reduced in L sows (.17, .5, and .5 vs 1.50, 1.17, and .83 pulses/6 h at d W-1, W, and W+1 respectively; P < .05). Mean and basal concentrations of LH were influenced by the day of sampling, being significantly increased within hours following weaning. Mean FSH concentrations were influenced neither by the level of feeding nor by the day of sampling. At weaning, the ovaries from L sows were lighter and had smaller follicles and fewer follicles > or = 4 mm (P < .05). Values of these macroscopic characteristics increased after weaning ( P < .05). At weaning, the percentage of healthy follicles was higher in the first class (< 1 mm) and lower in the second class (1 to 2.99 mm) in L compared to H sows (P < .05). Whatever the day of sampling, IGF-I concentrations in follicular fluid tended to be lower in L than in H sows. These results indicate that feed restriction during lactation inhibits LH pulsatility and ovarian activity.

Subacute and chronic myelomonocytic leukemia in children (juvenile CML). Clinical and hematologic observations, and identification of prognostic factors

The clinical and hematologic characteristics of 38 children with subacute and chronic myelomonocytic leukemia (S & CMMOL) are described, and the prognostic significance of these characteristics as recorded at diagnosis is reported. The common and distinctive feature of these children was the excessive proliferation of cells of neutrophilic and monocytic series. The disease predominated in younger children, 95% were younger than 4 years, and boys were more affected than girls (22/16). The onset of the disease was heralded most often by acute or subacute symptoms. Splenomegaly was the most common physical finding at diagnosis. Leukocytosis was usually under 100 X 10(9)/l. Monocytosis and granulocytosis were often associated with normoblastosis, and, in some cases, with moderate blastosis (less than or equal to 30%). Severe anemia and marked thrombocytopenia were found in about one third of patients, increased fetal hemoglobin levels in 53%, and increased gamma-globulin levels in 50% of cases. The Philadelphia chromosome was absent in all blood and marrow cell karyotypes. Thirty-three of 38 patients were treated with moderate or intensive chemotherapy, and in all cases treatment never resulted in a complete remission. Terminal acute leukemia occurred in 11 cases. Of the 38 patients, 29 have died (median survival time, 16 months). Initial characteristics predicting a short survival (log-rank test) included: older age (greater than or equal to 2 years) (P less than 0.001), hepatomegaly (P less than 0.05), bleeding (P less than 0.001), thrombocytopenia (P less than 0.01), high counts of blasts and normoblasts in peripheral blood (P less than 0.01, P less than 0.01). Sex, infections, cutaneous manifestations, lymphadenopathy, degree of splenomegaly, hemoglobin levels, fetal hemoglobin, leukocyte counts, percent of blasts in bone marrow, and serum gamma-globulin levels were of no prognostic value. When survival was plotted on a semilogarithmic scale, a change in death rate was evident at the second year of survival suggesting that there may be two subgroups of patients with myelomonocytic picture, one with very rapid, and another with a slower rate of mortality. A stepwise discriminant-function analysis was performed in an attempt to distinguish between those children who lived less than or equal to 2 years and those who lived longer. A linear combination of variables which best discriminated between these two subgroups was found. Nearly all patients could be classified as a short-survivor or long-survivor on the basis of age and platelet, blast, and normoblast counts in peripheral blood.(ABSTRACT TRUNCATED AT 400 WORDS)

Philadelphia chromosome-positive chronic myelocytic leukemia in children. Survival and prognostic factors

The survival and the prognostic significance of the diagnostic characteristics of 39 children with Philadelphia chromosome-positive chronic myelocytic leukemia (Ph1-positive CML), seen between 1963-1976 at the Hôpital Saint-Louis of Paris, have been analyzed. The disease predominated in children older than age 4 years (95%), with girls being more affected than boys (24 versus 15). The clinical and hematological picture at presentation was similar to that observed in adults with Ph1-positive CML. Most children of this series were treated with busulfan which, as in adults, led to reduction of leucocytosis and organomegaly but did not prevent the occurrence of blastic crisis. Well-documented blastic crisis was observed in 78% of cases. Of 39 children, 12 were still alive, all in the chronic phase. Twenty-seven have died, 21 of them after blastic crisis, 4-156 months after diagnosis (median survival, 53 months). The effect of each diagnostic characteristic on survival was evaluated using the log-rank test. Of the 14 characteristics studied, only the degree of blood and marrow blastosis was associated with a shorter survival. Age, sex, bleeding, lymphadenopathy, hepatomegaly, degree of splenomegaly, hemoglobin level, total leucocyte, immature granulocyte (promyelocytes + myelocytes + metamyelocytes), eosinophil, basophil, and platelet counts in the peripheral blood were of no prognostic significance. The failure to attain a level of statistical significance for some characteristics found to be of prognostic value for adults, could be due to the small sample size and/or to the disease homogeneity. The results of this study, however, stress the importance of the initial blastic infiltration in determining the duration of survival, which is ultimately determined by the occurrence of terminal acute leukemia. In conclusion, this study shows that the Ph1-positive CML of childhood exhibits the same course, incidence of blastic crisis, and survival as the disease of adults. It also indicates that treatment with moderate chemotherapy, such as busulfan, has no effect on the duration of survival. Therefore, new therapeutic approaches are urgently needed for the treatment of this disorder in children.

Long-term local and distal increases in tryptophan hydroxylase activity following intracerebral kainic acid injections in the rat

The administration of kainic acid (1--2 micrograms) into the right striatum of adult rats resulted in a marked local increase in tryptophan hydroxylase activity (+ 54--106%). This change was significant as soon as on the second day after the treatment and persisted for at least 12 days. In addition, long-lasting elevations of tryptophan hydroxylase activity were also observed in the anterior raphe area, septum and ipsilateral hippocampus and cerebral cortex. In contrast, the intrahippocampal injection of kainic acid (1 microgram) induced a long-term increase in tryptophan hydroxylase activity only in the injected structure. In all cases, the changes in tryptophan hydroxylase activity were associated with significant increases in the Vmax of the enzyme with no alteration of its apparent affinities for tryptophan and the pterin cofactor. Studies of the sensitivity of tryptophan hydroxylase from control and from kainic acid-treated rats to in vitro activating conditions (Ca2+-dependent phosphorylation, partial trypsinization, exposure to sodium dodecyl sulfate) suggest that the intrastriatal injection of the neurotoxin induced a long-lasting activation of the enzyme. These findings indicate that intracerebral injections of kainic acid may be a valuable approach to explore further the mechanisms controlling tryptophan hydroxylase activity in vivo.