Current state of affairs in the treatment of infrainguinal critical limb ischemia.

Atherosclerosis is widespread in Western society and is the leading cause of morbidity and mortality in the United States (US). Epidemiological studies indicate that peripheral artery disease (PAD) has a prevalence of 3-10% in the general population. This rate increases to 15-20% in persons over 70 years of age, and PAD is particularly common in individuals who smoke or have diabetes. Further highlighting the lack of current treatment uniformity, the Society for Vascular Surgery has recently designated the goal of clarifying optimal treatment for CLI as one of its top societal priorities.

Eastern oyster (Crassostrea virginica) delta(15)N as a bioindicator of nitrogen sources: Observations and modeling.

Stable nitrogen isotopes (delta(15)N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue delta(15)N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that delta(15)N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal delta(15)N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations.

A comparison of diagnostic techniques for postpartum endometritis in dairy cattle.

Holstein cows (n=221) from eight commercial dairy herds were examined for endometritis between 28 and 41 days postpartum using 5 diagnostic techniques: (1) vaginoscopy; (2) ultrasonographic assessment of uterine fluid volume; (3) ultrasonographic assessment of endometrial thickness; (4) endometrial cytology collected by cytobrush; and (5) endometrial cytology collected by uterine lavage. Concordance correlation was used to evaluate the reliability of cytobrush and lavage cytology. Cytobrush cytology was found to have the greatest intraobserver repeatability (cytobrush, rho(c)=0.85 versus lavage, rho(c)=0.76) and was chosen as the reference diagnostic test. Pregnancy data at 150 days postpartum was available for 189 cows. Survival analysis was used to determine the lowest percentage of polymorphonuclear cells associated with time to pregnancy. The sensitivity and specificity of the diagnostic techniques was determined using pregnancy status at 150 days and cytobrush cytology as the diagnostic standards. The risk of non-pregnancy at 150 days was 1.9 times higher in cows with more than 8% PMNs identified using cytobrush cytology than in cows with less than 8% PMNs (P=0.04). Twenty-one cows of 189 cows (11.1%) had >8% PMNs and were considered to be positive for endometritis. Cows with endometritis had a 17.9% lower first service conception rate (P=0.03) and a 24-day increase in median days open (P=0.04). The sensitivities of all five diagnostic tests relative to 150-day pregnancy status ranged from 7.1 to 14.3% and the specificities from 84.0 to 93.3%. Relative to cytobrush cytology, the respective sensitivity and specificity values are as follows: vaginoscopy (53.9%, 95.4%); lavage cytology (92.3%, 93.9%); ultrasonographic assessment of uterine fluid (30.8%, 92.8%); and ultrasonographic assessment of endometrial thickness (3.9%, 89.2%). Endometritis impaired reproductive performance. Cytobrush cytology was the most reliable method of diagnosing endometritis in cattle.

Frequency comb linewidth of an actively mode-locked fiber laser.

We report what is to our knowledge the first measurement of the linewidth of the frequency comb lines of a mode-locked Er-doped fiber laser. By propagating the output pulses through fiber as long as 1000 km in a modified self-heterodyne arrangement, we have measured the effective linewidth of the comb lines to be less than 12 kHz on a 5-ms time scale; the width is due primarily to frequency jitter from environmental fluctuations. Deconvolution of the spectral line shapes by use of Voigt analysis yields an upper limit of the intrinsic Lorentzian width of 3 kHz.

Dispersion management in a harmonically mode-locked fiber soliton laser.

Harmonically mode-locked Er-fiber soliton lasers have become a reliable source of high-repetition-rate picosecond pulses in high-speed communications and photonic analog-to-digital conversion systems because of their low-noise, dropout-free operation. We have fabricated such a laser with a strongly dispersion-managed cavity and modeled its operation, and we have found that dispersion management significantly extends the power range over which uninterrupted single-pulse production is attained and dramatically decreases the effects of amplified spontaneous emission on the phase noise of the laser.

Cross-phase modulation and multiwavelength adiabatic solitons.

In an experimental demonstration of four-channel, wavelength-division-multiplexed repeaterless transmission over 235 km, adiabatic soliton propagation allows for precise spectral characterization of cross-phase modulation effects during initial soliton collisions. Theoretical predictions of the spectral shifts that occur are verified for ultrashort solitons. The relationship between the frequency shift and the initial pulse separation is confirmed by measurement of the bit-error ratio as the pulse spacing is varied at the fiber input. Adiabatic expansion of narrow solitons may help to alleviate the channel restrictions that are required for prevention of soliton collisions at the fiber input.

Gallium arsenide metal-semiconductor-metal photodiodes as optoelectronic mixers for microwave single-sideband modulation.

Gallium arsenide (GaAs) metal-semiconductor-metal (MSM) photodetectors have unique properties including high-bandwidth, linearity, and biphase response that make them suitable as mixers and programmable weights for microwave and communications applications. An optical technique for microwave single-sideband modulation that uses GaAs MSM photodiodes as mixers is reported. It uses MSM Schottky photodiodes formed in a GaAs/Al(0.3)Ga(0.7)As materials system to detect microwave in-phase and quadrature signals on optical carriers. Modulation of the photodetector bias voltages results in a single-sideband modulation of the microwave signal. Radio frequency and undesired-sideband suppression of 36 and 27 dB, respectively, were achieved. The optical wavelength was 850 nm, and the bandwidth of the photodetectors was > or = 29 GHz.

Planar, Al0.3Ga0.7As-passivated-base, heterojunction bipolar phototransistors.

New planar GaAs heterojunction bipolar phototransistors have been designed and demonstrated. The devices use a GaAs/Al(0.3)Ga(0.7) As molecular-beam-epitaxy materials system with an Al(0.3)Ga(0.7) As passivated, 10-nm-thick base; a depleted, high-low emitter; and a low emitter-base capacitance. Electrical contact to the emitter is made by a set of parallel, ohmic fingers and to the collector by an ohmic contact formed in a large, approximately 1.48-microm deep via. Rise times in response to impulse optical excitation at 810 nm were 747-891 ps except at the two lowest optical excitation powers measured. Photocurrent gains measured at 810 and 850 nm were 0.67-19, depending on experimental conditions. These devices are promising for use in heterodyne photodetector arrays for coherent optical processing channelizers requiring a 100-MHz bandwidth.

Light climate and energy flow in the seagrass canopy of Amphibolis griffithii (J.M. Black) den Hartog.

Absorption of light and radiation use efficiency (RUE) were measured in a dense stand of the seagrass Amphibolis griffithii in Warnbro Sound, a temperate marine embayment in southern Western Australia. Total light intercepted by the canopy was measured and compared with dry weight leaf production, under both summer and winter conditions. RUE was found to be higher in winter (1.56 g MJ-1) than summer (1.01 g MJ-1). These values are very similar to values measured for annual crop plants and emphasise the value of applying theory developed for terrestrial crop plants to seagrasses. Canopy extinction coefficients were 0.93 m-1 in winter and 0.44 m-1 in summer. There were large differences in hours above saturating irradiance (H sat) between the top (Hsat = 5 h 14 min) and base (18 min) of the canopy in winter. Energy flows in A. griffithii suggest that this species is highly susceptible to short-term perturbations in incident irradience during the winter period as the energy stored within the rhizomes is small relative to daily respiratory demands.

10-GHz, 1.3-ps erbium fiber laser employing soliton pulse shortening.

An actively mode-locked single-polarization erbium fiber laser modulated at 10 GHz utilizes intracavity soliton formation to produce 1.3-ps pulses, well below the Kuizenga-Siegman limit, without passive mode locking. The observed degree of pulse shortening agrees with the predictions of recently developed soliton laser models. The pulse dropout ratio was measured to be less than 10(-12), and the rms amplitude and phase jitter are less than 1.1% and 0.16 ps, respectively.

Ovarian follicular development and endocrine responses in follicular-fluid-treated and hemi-ovariectomized heifers.

The effects of charcoal-extracted bovine follicular fluid (BFF) on endocrine profiles and follicular development in intact and hemiovariectomized postpubertal heifers were examined. Oestrus-synchronized heifers received Norgestomet implants on day 1 and 7 of treatment and were then injected s.c. with 11 ml saline (control) or 11 ml BFF twice a day for 12 days. The ovary bearing the largest follicle (OV1) was removed on day 7 and the remaining ovary (OV2) was collected on day 13. Follicles were observed by daily ultrasonography and were classified according to diameter (size 1: 2-3 mm; size 2: 4-6 mm; size 3: 7-10 mm; size 4: > 10 mm). After ovariectomy they were classified by diameter and histologically as normal or atretic. Intact control heifers had increased numbers of size 4 follicles on OV1 on days 6 and 7; no increase was observed in BFF-treated heifers (P < 0.03). In BFF-treated heifers, the mean basal LH concentration was higher (P < 0.05) and that of FSH was lower (P < 0.04) than in controls. FSH concentrations in BFF-treated heifers decreased from 0.60 +/- 0.08 ng ml-1 (day 1) to 0.22 +/- 0.05 ng ml-1 (day 7; P < 0.04). The concentration of oestradiol increased in control heifers, but not in BFF-treated heifers (P < 0.001). After hemicastration, OV2 underwent compensatory hypertrophy in control heifers, with an increase in the number of size 2, 3 and 4 follicles (P < 0.05), whereas BFF-treated heifers did not. Thus, total follicular volume was much lower in BFF-treated than in control heifers on day 13 (92.2 +/- 15.4 versus 1393.8 +/- 276.6 mm3; P < 0.0002). A transient increase in FSH (P < 0.006) and oestradiol (P < 0.01) concentrations occurred after hemiovariectomy in control but not in BFF-treated animals. In control heifers, an analysis of temporal relationships showed negative correlations between the volume of size 3 and size 4 follicles, and between FSH concentrations and the volume of size 3 and 4 follicles. A positive correlation was found between the mean diameter of the largest follicle and the concentration of oestradiol, whereas negative relationships were found between the concentrations of FSH and oestradiol, and between FSH and the mean diameter of the largest follicle. Analysis of the histological data showed that the number and volume of follicles > 8.57 mm was lower in the BFF-treated OV1 ovary, whereas no differences were found for follicles < or = 8.57 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

A survey of veterinarian and producer perceptions of herd health services in the Saskatoon milkshed.

A cross-sectional survey was conducted to determine the availability, rates of adoption, and producer perceptions of veterinary services in five areas of dairy production medicine: reproduction, milk quality, nutritional consulting, infectious disease control, and heifer rearing. Questionnaires were completed by all veterinary clinics and 86% of the dairy producers in the Saskatoon milkshed. Veterinary perceptions of services offered were compared with farmer perceptions of services received. The veterinary clinics appeared to overestimate their services in the areas of nutritional consulting and heifer rearing. The primary determinant of a producer's perception of being on a herd health program was the occurrence of regularly scheduled reproduction visits. Producers who perceived themselves as being on a herd health program also believed that they received more services in the other four main areas of production medicine. Grouping of producers, based on whether or not herd records were analyzed by their veterinarian, showed a clustering of adopters of more comprehensive herd health services as clients of two practices. This suggests that comprehensive herd health services are not readily available from all veterinary clinics in the Saskatoon milkshed.

Superovulation in the cow with pregnant mare serum gonadotrophin: effects of dose and antipregnant mare serum gonadotrophin serum.

The effects of pregnant mare serum gonadotrophin (PMSG) dose and PMSG antiserum on superovulation in crossbred beef cows were studied. In experiment I, three groups were treated with 1200, 2400 or 3600 IU of PMSG and 48 h later with prostaglandin (PGF). The mean numbers of corpora lutea (CL), unovulated follicles, and total ova/embryos collected increased as the PMSG dose increased. The percent of fertilized ova and transferable embryos was lowest in the highest dose group (p < 0.05). In experiment II, all cows received 2500 IU of PMSG; groups 1 and 2 were treated with sheep anti-PMSG serum at 48 h or 60 h after PGF; group 3 cows were PMSG-only controls. The number of CL was lowest and the number of unovulated follicles highest in the PMSG-only group (p < 0.05). The number of CL was higher in group 2 (anti-PMSG at 60 h) than in the control group, with the anti-PMSG at 48 h not different from the other groups. Numbers of total ova/embryos, fertilized ova, and transferable embryos were higher (p < 0.05) in both antiserum-treated groups relative to the PMSG-only group. We conclude that superovulation of beef cows with PMSG and treatment with PMSG antiserum will induce a higher superovulatory response and will result in higher CL numbers and fewer unovulated follicles. Further, the variability in the superovulatory response to PMSG treatment was still evident when PMSG antiserum was administered.

Role of luteal regression in embryo death in cattle.

Inseminated crossbred beef cows and heifers were used in 2 experiments to investigate embryo survival after prostaglandin-induced or spontaneous luteal regression. In Experiment 1, luteal regression was induced by an intramuscular (im) injection of cloprostenol (500 mug) on Day 15 (day of ovulation = Day 0). Progestagen was replaced 24 or 36 h later either by one-and-a-half Syncro-Mate-B (SMB) ear implants (9 mg of norgestomet) and norgestomet solution (2.25 mg, im) containing no estradiol in 1 replicate or by 2 SMB implants (12 mg of norgestomet) and progesterone (100 mg, im) in the second replicate. Combined for both replicates, the Day-24 pregnancy rate in an untreated control group (Group 1, 16/19; 84%) was higher (P < 0.01) than in the 24-h group (Group 2, 9/20; 45%), which also was higher (P < 0.02) than in the 36-h group (Group 3, 3/23; 13%). In Experiment 2, 15 or 16 d after breeding, cattle with a corpus luteum at least 16 x 16 mm were given either 2 SMB implants or no treatment. At 24 to 26 d after breeding, pregnancy rates (48/65, 74% versus 49/68, 72%) were not significantly different, and all but 1 of the pregnant progestagen-supplemented cattle had a functional corpus luteum.

Effects of bovine follicular fluid and partially purified bovine inhibin on FSH and LH release by bovine pituitary cells in culture.

We have established a dispersed bovine pituitary cell culture system to study the effects of charcoal-extracted bovine follicular fluid (BFF) or bovine inhibin, partially purified by immunoaffinity chromatography (IPI), on the spontaneous release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Pituitary cells were plated at 0.25, 0.5 or 1 x 10(6) viable cells/well (c/w) and incubated for 48 h. The medium was replaced and BFF (0, 0.54, 2.7, 13.7, 68.7 or 343.5 micrograms protein) or IPI (0, 0.01, 0.06, 0.29, 1.45 or 7.25 micrograms protein) added to the cultures and the incubation was continued for 48 h. Concentrations of FSH and LH in spent medium were determined by RIA and data analyzed by ANOVA with means compared by Student-Neuman-Keuls (SNK) test. We have shown an increase in spontaneous FSH and LH release attributable to both number of bovine pituitary cells plated and to the length of incubation. The addition of BFF reduced spontaneous FSH release over 48 h incubation. The dose-dependent inhibition curves observed in culture in which different numbers of cells were plated, indicates that inhibition was greater when 1 x 10(6) c/w were plated compared to 0.25 or 0.5 x 10(6) c/w. Bovine follicular fluid at 0.45 micrograms of protein (equivalent to 0.01 microliters of BFF) incubated with 1 x 10(6) c/w, suppressed FSH release by 10.6% compare to control. Maximal suppression of 34.1% was obtained with 50 micrograms (equivalent to 1.56 microliters of BFF). Immunopurified bovine inhibin at 1.45 micrograms tended to suppress FSH release and at 7.25 micrograms significantly reduced FSH release. Neither BFF nor IPI had a measurable effect on LH release. We conclude that BFF and IPI suppress the spontaneous release of FSH from bovine pituitary cells in culture in a dose-dependent manner, without concomitant suppression of LH release.

Superovulation of beef heifers with Folltropin: A new FSH preparation containing reduced LH activity.

The optimum superovulatory dose of Folltropin was determined and compared with a standard 28 mg dose of FSH-P in beef heifers. In Experiment 1, mean numbers of corpora lutea (CL) did not differ among the groups treated with 10, 20, 30 or 40 mg Folltropin or FSH-P, and the mean CL number was reduced (P<0.05) only in the 5 mg Folltropin group. Mean numbers of ova/embryos recovered, fertilized and transferable were greater (P<0.05) for the 10, 20 and 30 mg Folltropin groups than for the 5 mg group. The 40 mg Folltropin group and the FSH-P group were intermediate. The percentage of fertilized and transferable embryos did not differ over the dosages used in this experiment. In Experiment 2, mean numbers of CL were greater for the 9, 18 and 36 mg Folltropin groups than for the 4.5 mg group, with the 9 mg group being lower than the 36 mg group (P<0.05). The 18 mg group was intermediate and did not differ. Mean numbers of ova/embryos recovered and fertilized ova were greater for the 9, 18 and 36 mg groups (P<0.05) than for the 4.5 mg group. The percent of fertilized and mean number and percentage of transferable embryos did not differ among treatments. We conclude that Folltropin may be a satisfactory superovulatory replacement for FSH-P and that a dose of 18 to 20 mg Folltropin may be within the optimum superovulatory dosage range for beef heifers. Dosages of Folltropin of more than twice the optimum did not result in deterioration of ova/embryo quality.

Passive laser mode locking with an antiresonant nonlinear mirror.

A nonlinear mirror that is based on an antiresonant ring incorporating a nonlinear element sensitive to the polarization state of the circulating light has been developed. No phase matching of the mirror to the laser cavity is necessary, so the mirror does not need active length stabilization. Spontaneous mode locking occurs when the mirror is incorporated into a cw Nd:YAG laser. Pulses of 11-psec duration are produced at 1064 nm; two output beams at 532 nm are also generated. An analysis indicates that the primary mechanism responsible for passive mode locking is self-phase modulation in the nonlinear element.

Endocrine and superovulatory responses in heifers pretreated with FSH or bovine follicular fluid.

This study examined the effects of altered serum FSH concentration on subsequent ovarian response to superovulation. Synchronized heifers were assigned randomly on Day 1 of the cycle (estrus = Day 0) to three pretreatment groups that consisted of 6-d of saline (7ml, s.c., b.i.d.; Group I), FSH-P (0.5 mg, i.m., b.i.d.; Group II) or charcoal-extracted bovine follicular fluid (BFF; 7 ml, s.c., b.i.d.; Group III) injections. Superovulation was initiated on Day 7 and consisted of FSH-P in decreasing dosages over 4 d (4,3,2,1 mg; i.m., b.i.d.), with cloprostenol (500 mug) on the morning of the third day. A second replicate with 14 heifers was conducted using the same protocol but twice the pretreatment dosage of FSH-P (1 mg) and BFF (14 ml). Endogenous plasma FSH decreased during BFF and FSH-P pretreatments compared to controls (P < 0.02). Endogenous FSH concentrations in both primed groups (II and III) were similar to control values (Group I) 12 h after the start of superovulation. Basal LH concentrations were not different between pretreatment groups. The interval from cloprostenol treatment to the preovulatory LH surge in Group III was 21.3 and 23.9 h longer (P < 0.0001) than it was in Groups I and II. The postovulation progesterone rise was delayed in Group III. The number of corpora lutea (CL) was lowest in the BFF-primed group (4.2 +/- 0.8) compared with the FSH-primed (7.4 +/- 1.3) and the control (12.0 +/- 1.8; P < 0.003) groups. In the FSH-primed group (0.68 +/- 0.06 cm(3)), CL volumes were larger than in the control group (0.45 +/- 0.03 cm(3)), whereas in the BFF-primed group (0.27 +/- 0.02 cm(3)) CL volumes were smaller compared with the control group (P < 0.0001). Mean FSH concentrations for 48 h preceding superovulation and the number of CL per cow were positively correlated (r = 0.55; P < 0.004; n = 26). We concluded that both FSH-P and BFF pretreatments decreased the superovulatory response of heifers to FSH-P. The mechanism for this would appear to be associated with reduced endogenous FSH prior to the start of superovulation.