Optical fiber bundles: Ultra-slim light field imaging probes.

Optical fiber bundle microendoscopes are widely used for visualizing hard-to-reach areas of the human body. These ultrathin devices often forgo tunable focusing optics because of size constraints and are therefore limited to two-dimensional (2D) imaging modalities. Ideally, microendoscopes would record 3D information for accurate clinical and biological interpretation, without bulky optomechanical parts. Here, we demonstrate that the optical fiber bundles commonly used in microendoscopy are inherently sensitive to depth information. We use the mode structure within fiber bundle cores to extract the spatio-angular description of captured light rays-the light field-enabling digital refocusing, stereo visualization, and surface and depth mapping of microscopic scenes at the distal fiber tip. Our work opens a route for minimally invasive clinical microendoscopy using standard bare fiber bundle probes. Unlike coherent 3D multimode fiber imaging techniques, our incoherent approach is single shot and resilient to fiber bending, making it attractive for clinical adoption.

A dual-mode mobile phone microscope using the onboard camera flash and ambient light.

Mobile phone microscopes are a natural platform for point-of-care imaging, but current solutions require an externally powered illumination source, thereby adding bulk and cost. We present a mobile phone microscope that uses the internal flash or sunlight as the illumination source, thereby reducing complexity whilst maintaining functionality and performance. The microscope is capable of both brightfield and darkfield imaging modes, enabling microscopic visualisation of samples ranging from plant to mammalian cells. We describe the microscope design principles, assembly process, and demonstrate its imaging capabilities through the visualisation of unlabelled cell nuclei to observing the motility of cattle sperm and zooplankton.

Impact of lactation length and piglet weaning weight on long-term growth and viability of progeny.

A total of 1,034 pigs produced by breeding PIC sows to 2 different PIC terminal sires were used to create 3 distinct weaning weight populations so that postweaning growth to 125 kg could be studied. The rearing strategies resulted in BW that ranged from 4.1 to 11.5 kg by 20 d of age. Sows and corresponding litters were allocated to 3 treatments: sow reared (SR; n = 367) for 20 d, sow reared for 14 d (14W; n = 330), and sow reared for 2 d (2W; n = 337). Sows were removed from 2W and 14W groups, but progeny remained in the crates and received milk replacer ad libitum (for 18 and 6 d, respectively) until the contemporary SR pigs were weaned at 20 d of age. The SR pigs (6.49 +/- 0.15 kg) weighed 1.01 kg less than 14W pigs (7.5 +/- 0.14 kg) and 2.26 kg less than 2W pigs (8.75 +/- 0.14 kg; P < 0.05). The 14W pigs weighed 1.25 kg less than 2W pigs (P < 0.05). Nursery ADG for the 2W group (547 g/d) was 35 g/d less (P < 0.05) than 14W pigs. The 14W pigs (165 d) required 3 fewer (P < 0.05) days to reach 125 kg of BW compared with SR pigs. The SR and 14W pigs gained BW 24 and 20 g/d faster (P < 0.05) in the postnursery period when compared with 2W pigs. The SR and 2W pigs consumed 0.10 and 0.12 kg/d less (P < 0.05) during this period when compared with 14W pigs (2.32 kg/d). Gain:feed of SR was improved (P < 0.05) when compared with the 14W and 2W pigs over 167 d of age (0.44 vs. 0.42 and 0.42, respectively). Lean percentage was 0.7% greater (P < 0.05) in carcasses from SR pigs (55.0%) compared with carcasses from 2W pigs (54.3%) when adjusted to a constant HCW. A study of the effect of weaning weight on days to 125 kg was limited to SR and 14W groups because maternal deprivation compromised the 2W group postweaning growth. Six weaning-weight groups were defined using a normal distribution: 4.6, 5.5, 6.4, 7.3, 8.2, and 9.5 kg. Pigs weighing 5.5 kg at 20 d of age were able to reach 125 kg 8 d sooner (168.8 d) than those weighing 4.6 kg (176.8 d). There was a linear relationship (P < 0.05) between weaning weight and ADG in the postnursery phase of growth. We conclude that 1) a weaning weight of less than 5.0 kg imposes the greatest marginal loss in production output for a 20-d weaning and 2) lactation length influences long-term growth, composition of growth, and viability of progeny.

Long-term outcomes of thigh circumference, stifle range-of-motion, and lameness after unilateral tibial plateau levelling osteotomy.

Our study evaluated thigh circumference (TC), stifle range of motion (ROM), and lameness in dogs one to five years after unilateral tibial plateau levelling osteotomy (TPLO). We hypothesised that TC, stifle ROM, and lameness would not be different to the unoperated limb (control), one to five years after surgery. Patients that were one to five years post-TPLO were reviewed and were included if they had a unilateral TPLO, and no additional clinical evidence of orthopaedic disease. Standing mid-thigh TC measurements and stifle extension and flexion angles were made in triplicate. Clinical lameness was graded blindly. Data were evaluated statistically using paired t-tests for TC and stifle flexion and extension. Significance was set at p <0.05. Twenty-nine dogs met the inclusion criteria. Mean results for the surgery limbs and control limbs were 39.5 +/- 5.5 cm and 40.1 +/- 5.6 cm for TC, 36.6 +/- 6.8 degrees and 28.6 +/- 4.3 degrees for stifle flexion, and 155.2 +/- 6.6 degrees and 159.8 +/- 4.9 degrees for stifle extension, respectively. The mean TC for the operated limb was 98.5% of the control limb. A significant difference was found between the operated and the control limbs for all measurements. Time after surgery had no apparent affect on outcome. Four of 29 dogs (14%) exhibited some lameness in the TLPO limb during evaluation (one dog was 1 to 2 years postoperative and three dogs were 2 to 3 years postoperative). These results indicate that TC and stifle ROM in the TLPO limb do not return to control-limb measurements one to five years after a TPLO surgery. The clinical significance is unknown as TC returned to 98.5% of control, and the source of lameness in the lame dogs was not identified.

The effect of computed tomographical gantry angle on the measurement of the canine intercondylar notch.

This study was conducted to evaluate the clinical application of computed tomography of the canine femoral intercondylar notch. The canine femoral intercondylar notch is angled 12 degrees from the dorsal plane and obliqued 7 degrees proximolateral to distomedial in the sagittal plane. Measurements of the notch were performed with eight, 12, and 16 degrees of gantry tilt. With the exception of proximal opening notch angle, significant differences were not detected in measurements referenced to 12 degrees of gantry tilt. Evidence from this study indicated that a +/- 4 degree variation in gantry tilt angle from a desired angle of 12 degrees did not significantly affect clinical interpretations of intercondylar notch measurements or notch width index ratios.

Outcome and prognostic factors in non-ambulatory Hansen Type I intervertebral disc extrusions: 308 cases.

Thoracolumbar intervertebral disc disease is the most common cause of caudal paresis in dogs. Whilst the pathogenesis of the extrusion has been widely studied, treatment protocols and prognostic factors relating to outcome remain controversial. Recent studies have examined a multitude of factors relating to time to regain ambulation after decompressive surgery. Most intervertebral disc herniations occur in the thoracolumbar region, causing upper motor neuron signs in the rear limbs, which are thought to have a more favourable prognosis compared to the lower motor neuron signs created by herniation of an intervertebral disc in the caudal lumbar region. Due to the potential disruption of the lumbar intumescence, lower motor neuron signs have been reported as having a less favourable prognosis. The purpose of this study was to evaluate the intervertebral disc space as a prognostic factor relating to ambulatory outcome and time to ambulation after decompressive surgery. Hansen Type I intervertebral disc extrusions were studied in 308 non-ambulatory dogs. Preoperative and postoperative neurological status, corticosteroid use, signalment, intervertebral disc space, postoperative physical rehabilitation, previous hemilaminectomy surgery, disc fenestration, return to ambulation, and time to ambulation were reviewed.

Comparison of radiographic arthritic changes associated with two variations of tibial plateau leveling osteotomy.

Osteoarthritis (OA) progresses in the canine cranial cruciate ligament (CCL) deficient stifle. Progression of OA is also documented in canine patients after various surgical repair techniques for this injury. We evaluated the radiographic arthritic changes in canine stifle joints that have sustained a CCL injury, and compared radiographic OA scores between Tibial Plateau Leveling Osteotomy (TPLO)surgery patients receiving a medial parapatellar exploratory arthrotomy for CCL remnant removal versus those receiving a limited caudal medial arthrotomy without removal of the CCL remnants. Medial/lateral and caudal/cranial stifle radiographs were obtained before surgery, immediately following TPLO surgery and at 7-38 months (mean 20.5) after surgery. Sixty-eight patients (72 stifles) were included in the study. The cases were divided into two groups. The patients in group 1 (n = 49 patients, 51 stifles) had a limited caudal medial arthrotomy, and patients in group 2 (n = 19 patients, 21 stifles) had a medial parapatellar open arthrotomy. A previously described radiographic osteoarthritis scoring system was used to quantify changes in both of the groups. The age, weight, OA scores, initial tibial plateau angle, final tibial plateau angle, and the change in angle were compared between the groups. The results showed that there was significantly less progression of OA in the group that had the limited caudal medial, arthrotomy, versus a medial parapatellar open arthrotomy. There was a significant advancement of the OA scores of patients that had TPLO surgery.

Relationships between longissimus glycolytic potential and swine growth performance, carcass traits, and pork quality.

The relationships between glycolytic potential and growth performance, carcass traits, and pork quality were investigated in a group of 72 pigs from the same genetic line. Glycolytic potential (GP) was determined on live-animal biopsy samples and postmortem samples taken from the longissimus muscle, and free glucose concentration was measured on the exudate from the longissimus muscle taken postmortem. The mean live-animal and postmortem GP and free glucose values were 201.6 micromol/g (range = 113.8 to 301.1), 149.8 micromol/g (range = 91.0 to 270.5) and 110.1 mg/dL (range = 30.0 to 406.0), respectively. Correlations between live-animal and postmortem GP and free glucose ranged from 0.47 to 0.70; however, all three measures were weakly related to growth and carcass traits (r = 0.03 to -0.22; P > 0.05). Correlations of GP and free glucose values with fresh pork quality measurements were moderate (r = 0.23 [P < 0.05] to -0.63 [P < 0.001]). Regression analysis suggested that a one standard deviation increase in live-animal and postmortem GP and free glucose resulted in an increase in L* values (0.99, 1.32, and 2.05, respectively) and drip loss (0.85, 1.10, and 1.39 percentage units, respectively), as well as a decrease in ultimate pH (0.05, 0.11, and 0.16, respectively). Correlations between GP and cooking loss and tenderness and juiciness scores ranged between 0.16 (P > 0.05) to 0.34 (P < 0.01). Free glucose concentration showed no relationship (P > 0.05) with cooking loss, tenderness, and juiciness. Regression analysis suggested that a one standard deviation increase in live-animal and postmortem GP increased cooking loss (1.26% and 1.65%, respectively) and would improve taste panel tenderness (0.54 and 0.44, respectively) and juiciness (0.40 and 0.48, respectively) scores. Increasing GP and free glucose was also associated with decreased longissimus fat and protein, and increased moisture contents (r = 0.14 [P > 0.05] to -0.45 [P < 0.001]). Overall, relationships with fresh meat quality characteristics were stronger for free glucose values than either live-animal or postmortem GP. Results from this study indicate that decreasing longissimus GP and free glucose concentrations may improve pork color and water-holding capacity.

The growth performance of the progeny of two swine sire lines reared under different floor space allowances.

A total of 736 pigs was used in a study with a 2 x 2 x 2 factorial arrangement to investigate the effects of and interactions between sire line (Line A vs. B), floor space (unrestricted vs. restricted), and gender (barrow vs. gilt) on growth performance, BW, and protein and estimated lipid accretion curves from 40 to 120 kg of BW. Pigs were by eight Line-A and nine Line-B sires mated with PIC C22 dams. Line A was of Pietrain ancestry and Line B was a synthetic line. The unrestricted floor space treatment consisted of small groups (four pigs) with 0.93 m2/pig of floor space for the entire grow-finish period. Pigs in the restricted floor space were in larger groups (12 pigs) with 0.37 and 0.56 m2/pig of floor space for the grower and finisher phases, respectively. Pigs were given ad libitum access to a three-phase dietary program, and one and three nipple waterers were available in the groups of 4 and 12 pigs, respectively. No sire line x floor space interactions were found for any of the traits measured. Line A pigs grew more slowly (50 g/d, P < 0.05), took longer (4.1 d, P < 0.05) to reach harvest weight (120.3 kg), and had similar feed intakes, but a lower gain:feed ratio (2.8%, P < 0.05) than Line B pigs. Line A pigs had greater longissimus muscle depth (P < 0.05) and estimated protein accretion rate (P < 0.05) than Line B pigs, but Line A and Line B pigs had a similar estimated percentage of lipid-free soft tissue. Pigs reared in the restricted floor space grew more slowly (105 g/d, P < 0.05) and consumed less feed (280 g/d, P < 0.05) but had a similar (P > 0.05) gain:feed ratio to pigs reared in the unrestricted floor space. Pigs reared in the unrestricted floor space had greater (P < 0.05) predicted protein and lipid accretion rates throughout the growth period than pigs reared in the restricted floor space. Differences between genders for growth traits and carcass measurements were in agreement with previous research. The differences in growth performance, carcass measures, and compositional growth curves between these two sire lines were similar in the two floor spaces.

Carcass and meat quality characteristics of the progeny of two swine sire lines reared under differing environmental conditions.

The objective of this study was to compare the carcass and meat quality of pigs of two sire lines (A vs B) reared in either a spacious or crowded environment. A total of 128 pigs (barrows and gilts) were used in the study. Animals were slaughtered at 120 kg live weight. Dressing percentage was greater for line A in the spacious but not the crowded environment and line A had a greater loin eye area than line B. Compared to line B, the longissimus from line A had lower pH, higher L* and b* values, and was judged to be paler and softer with a lower marbling fat content. Longissimus L* values were lower for pigs reared in the crowded compared to the spacious environment. Longissimus drip loss was greater for line A compared to line B in the spacious but not the crowded environment. This study highlights genetic differences in pork quality and suggests rearing environment effects that warrant further study.

Effect of dietary lysine level and environmental temperature during the finishing phase on the intramuscular fat content of pork.

This study was designed to investigate the effects of dietary lysine level on the intramuscular fat content of the longissimus in finishing pigs reared at two environmental temperatures. Seventy-two hybrid gilts were individually penned and given ad libitum access to either a diet formulated to meet their lysine requirement (6.4 g/kg lysine) or a lysine-deficient diet (4.8 g/kg). Pigs were held at one of two environmental temperatures (thermoneutral [18 degrees C] or hot [32 degrees C]). The study was carried out between approximately 90 and 126 kg live weight; pigs in the thermoneutral and hot environments were on test for 5 and 7 wk, respectively. There were no interactions between dietary lysine level and environmental temperature. Dietary lysine content did not influence feed intake or average daily gain; however, pigs on the lysine-deficient diet had a poorer gain:feed ratio than those fed to requirement (P < .01). High environmental temperature decreased feed intake (P < .001) and average daily gain (P < .01) but improved gain:feed ratio (P < .01). Backfat at the 10th rib was increased and loin eye area and estimated percentage lean in the carcass were decreased for pigs on the lysine-deficient diet. The higher environmental temperature resulted in an increase in carcass length but had no effect on other carcass measurements or intramuscular fat. Feeding the lysine-deficient diet resulted in an increase of .55 percentage unit in longissimus intramuscular fat content (P < .01); however, there was no difference in subjective marbling scores between the diets. Warner-Bratzler shear force values were not affected by dietary lysine level or environmental temperature. Results from this study suggest that feeding of lysine-deficient diets at the end of the finishing period can increase intramuscular fat deposition under thermoneutral and hot conditions.

Feed intake pattern of group-housed growing-finishing pigs monitored using a computerized feed intake recording system.

The feed intake pattern and growth performance of boars, barrows, and gilts fed diets differing in lysine and protein content were measured on 120 crossbred pigs from 27 (SD 3.7) to 81.5 (SD 9.2) kg live weight. The pigs were housed in eight mixed-sex groups with five pigs of each sex in each group. They were fed from an electronic feed station that recorded individual meal sizes and the time and duration of visits to the feeder for each animal in the group. Four dietary treatments were compared. During the grower period (27 to 55 kg), diets ranged in lysine content form .98 to 1.31%; for the remainder of the study, lysine content was .88 to 1.18%. Barrows had a greater (P < .01) number of meals per day than the other two sexes (7.4 vs 7.0 vs 7.0 +/- .10, respectively), but there were no significant differences among sexes for daily feed intake or other feed intake traits. Daily feed intake increased with dietary lysine content, largely because of increased meal sizes resulting from longer feeder occupation times at each visit. Visits to the feeder were greatest between 0900 and 1100 and lowest between 2000 and 0400. Correlations between feeding pattern and growth traits were relatively low. Repeatabilities of feeding pattern traits were generally higher when measured over shorter time periods. These results suggest a change in feeding behavior with increasing dietary lysine levels and a relatively small effect of sex on feeding pattern for mixed-sex groups of 15 pigs fed from a single electronic feed station.

Radiographic, computed tomographic and magnetic resonance imaging evaluation of a chronic long digital extensor tendon avulsion in a dog.

Long digital extensor tendon avulsion is reported in a 5 month old Great Dane. Clinically the dog presented with a unilateral weight-bearing pelvic limb lameness. Joint effusion was present and there was pain and crepitance associated with flexion of the stifle. Orthopedic evaluation and radiographs were suggestive of a long digital extensor tendon injury which was confirmed by computed tomography and magnetic resonance imaging. The injury was surgically repaired with screw and spiked washer fixation.

Influence of slaughter weight and stress gene genotype on the water-holding capacity and protein gel characteristics of three porcine muscles.

The longissimus lumborum, gluteus medius, and the triceps brachii muscles from 40 animals were used to evaluate the effect of stress gene genotype (non-mutant, NN and mono-mutant, Nn) and live weight at slaughter (110 kg and 140 kg) on the processing quality of fresh pork. The 45 minute and ultimate pH measurements did not differ between genotypes. Total percent protein was not different between samples taken from NN or Nn pigs, nor were there any differences in salt-soluble protein. The M. longissimus lumborum from Nn pigs possessed lower water-holding capacity values and lost greater amounts of water upon cooking. In addition, Nn pigs had lower subjective color and firmness scores which suggest a higher incidence of pale, soft and exudative pork. Slaughter weight did not affect total protein, salt-soluble protein, Minolta L(∗), a(∗) and b(∗) values or subjective color, firmness and marbling scores. Back fat thickness and loineye area increased as slaughter weight increased. Overall, this study suggested that Nn pigs have reduced water retention properties which may result in lower yields in processed meat items. Slaughter weight had limited effects on the processing quality of meat from NN or Nn pigs. There were no interactions of significance between stress gene genotype and slaughter weight, suggesting that the differences in muscle quality and functional properties between NN and Nn pigs are maintained over the slaughter weights used in this study.

Comparison of transverse and longitudinal real-time ultrasound scans for prediction of lean cut yields and fat-free lean content in live pigs.

Live animal real-time ultrasound scans and carcass measures were taken on 80 pigs comprising two sexes (42 barrows; 38 gilts) and two halothane genotypes (40 carriers and 40 negatives) that were slaughtered between 108 and 148 kg live weight. Transverse scans (TRUS), at right angles to the midline, were taken on right (RS) and left (LS) sides at the last rib. Longitudinal scans (LON) were taken 6.5 cm off the midline immediately anterior (ANT) and posterior (PST) to the last rib on both the RS and LS. Longissimus muscle depth and area and backfat thickness over the longissimus muscle were measured on TRUS. Backfat thickness and longissimus muscle depth were measured at each end of the LON. Backfat thickness and longissimus muscle measurements were taken at the 10th and last rib on the RS of the carcass. Carcasses were fabricated using standard techniques to establish lean cut yields and carcass soft tissue was chemically analyzed to determine fat-free lean contents. Stepwise regression analysis was performed to develop equations to predict the weights and percentages of lean cuts and fat-free lean. Fat and muscle measures taken from ultrasound scans were generally less accurate than last rib carcass measures at predicting composition. There was little difference in R2 for equations based on either TRUS or ANT/LON; however, PST/LON, generally, were less accurate than ANT/LON. Combining measurements from more than one scan gave little improvement in R2 compared with the best single scan. Estimates of sex bias for carcass composition prediction were small. Halothane genotype and carcass lean content biases were detected; equations derived from the pooled data tended to overestimate the lean content of negative pigs and fatter carcasses and underestimate the lean content of carrier animals and leaner carcasses.

The growth performance, carcass characteristics, and meat quality of halothane carrier and negative pigs.

Growth performance, carcass characteristics, and meat quality of halothane carrier (Nn) and negative (NN) pigs grown from 40 kg live weight and slaughtered at three weights (110, 125, and 140 kg live weight) were studied. Daily gains were similar for the two genotypes (974 g for Nn and 964 g for NN), but Nn pigs had a higher gain:feed ratio than NN pigs (P < .01). Dressing percentage was higher in Nn pigs than in NN pigs (P < .001), but there were no genotype differences for carcass length, backfat thickness, or loin eye area. Percentage yield of trimmed, boneless wholesale cuts was higher for Nn pigs than for NN pigs (P < .05). This resulted from higher trimmed, boneless ham, boston, and picnic weights (P < .05) in Nn than in NN pigs (6.9, 3.2, 3.5 kg vs 6.6, 3.0, 3.4 kg, respectively). The weight of fat-free lean was higher in Nn pigs (P < .05). The longissimus thoracis muscle from carrier pigs had lower 45 min (P < .001) and 24 h (P < .01) pH. Longissimus lumborum samples from carriers had lower (P < .001) subjective' meat quality scores and a higher drip loss (P < .001); however, cooking loss, eating quality, and shear force values were similar for the two genotypes. There were no important slaughter weight x genotype interactions for the traits reported. Overall, the data from this study suggest Nn pigs had an advantage over NN pigs in terms of feed efficiency, carcass yield fat-free lean content, and commercial lean cut yields but had a higher incidence of PSE.

A comparison of laparoscopic and belt-loop gastropexy in dogs.

A simplified technique for laparoscopic gastropexy (group 1) was compared to belt-loop gastropexy (group 2) in eight adult male dogs randomly divided into two groups of four dogs each. Our hypothesis was that a satisfactory laparoscopic gastropexy would approximate the strength and operative time required for belt-loop gastropexy. Operative time, surgical complications, postoperative morbidity, gross and histological appearance, radiographic microvascularization, and maximal tensile strength were measured and compared between the two groups. All dogs recovered from surgery. No morbidity was associated with either procedure. The mean (+/- SD) duration of surgery was 69.75 +/- 7.23 minutes for group 1 and 58.75 +/- 7.63 minutes for group 2. Fifty days after surgery, the microvascular appearance of the gastropexy site was similar for both groups. Blood vessels were observed within each seromuscular flap but vascular ingrowth to the abdominal musculature was observed in only two dogs, one from each group. The maximum tensile strength at 50 days was 76.55 +/- 22.78 for group 1 and 109.21 +/- 22.29 N for group 2. Differences between surgical duration and maximum tensile strength were not statistically significant (P > .05). Histologically, all gastropexies consisted of an adhesion composed of dense fibrous connective tissue. The results of this study indicate that laparoscopic gastropexy provides a minimally invasive alternative to open abdominal prophylactic gastropexy in dogs.

Properties of bispecific single chain antibodies expressed in Escherichia coli.

Single chain bispecific antibodies, in which the genes that encode the VH and VL regions are linked in tandem, may offer some advantages over other methods of bispecific antibody preparation. To begin to evaluate the potential of this system, a single chain bispecific antibody (scFv2) that binds to the T cell receptor of a cytotoxic T cell clone and to the hapten fluorescein was constructed. The individual scFv regions were joined by a 25 amino acid linker, and the scFv2 protein was obtained from insoluble inclusion bodies after guanidine solubilization and refolding. Fluorescein-purified scFv2 is active at concentrations of approximately 10 nM (approximately 1 microgram/ml) and above in mediating lysis of fluorescein-coupled tumor cells by the cytotoxic T lymphocytes (CTL). This system has now been used to evaluate various features of the scFv2 approach: (a) affinities of the scFv2 for the TCR and fluorescein, (b) yields of the scFv2 from several different purification schemes, (c) relationship of antigen density (i.e., fluorescein density on tumor cells) to the ability to redirect lysis of the tumor cell, and (d) relationship of scFv2 affinity for the tumor antigen to the ability to redirect lysis. This study was performed by using several analogs of fluorescein for which the scFv2 had different affinities. Results showed that it should be possible to select antibodies with appropriate affinities such that tumor cells with typical antigen densities of 10(4)-10(5) molecules per cell will be lysed and normal cells that have lower levels of the antigen will be spared.

Observation of a secondary compressive lesion after treatment of caudal cervical spondylomyelopathy in a dog.

In a 7-year-old Doberman Pinscher with an atactic gait, neurologic examination revealed tetraparesis, conscious proprioceptive deficits, and rigid ventral flexion of the neck. Radiography and myelography revealed a ventral, extradural, dynamic compressive lesion between C6 and C7. Distraction decompression was performed, using cancellous bone screws and methylmethacrylate. After initial improvement, clinical signs recurred 2 weeks after surgery and progressed until the dog was euthanatized 6 weeks after surgery. Postmortem myelography revealed an extradural compressive lesion adjacent to the implant, between C5 and C6. Secondary compressive lesions induced by surgical or biomechanical alterations of the cervical portion of the spine may be complications of treatment of caudal cervical spondylomyelopathy.

Characterization of skin prick testing responses for detecting sensitization to detergent enzymes at extreme dilutions: inability of the RAST to detect lightly sensitized individuals.

We observed that a group of detergent enzyme workers with known exposure to the subtilisin enzyme, Alcalase (Novo Industries, Bagsvaerde, Denmark), exhibited percutaneous sensitivity to Savinase (Novo Industries), a microbial protease, to which there was no previous occupational exposure. This was attributed to either cross-reactivity between these enzymes or to foreign enzyme contaminants contained in the Savinase antigen. The aims of this study were to determine the range of concentrations eliciting percutaneous responses to Alcalase and to another enzyme, Rapidase (an alpha-amylase) (Gist Brocades, Belgie, Netherlands); to compare the sensitivity of RAST and skin prick testing; and to characterize the relationship between wheal size and antigen concentration. Prick testing was conducted over six log10 antigen dilutions of Alcalase and Rapidase in 30 workers with previous exposure and skin reactivity to enzymes (group 1) and compared to nonexposed control groups, which included 60 atopic subjects (group 2) and 30 nonatopic subjects (group 3). The RAST was performed with Alcalase and Rapidase antigens. The percutaneous threshold concentrations in group 1 subjects varied widely from 10(3) to 10(-3) micrograms of protein per milliliter. Of 19 group 1 workers with skin test reactivity to Alcalase, 84% had positive RAST results; 83% of 24 workers who were reactive to Rapidase had positive RAST results. It was concluded that skin prick testing is preferred over in vitro methods for longitudinal monitoring of human sensitization to workplace allergens. In addition, the data predicted that based on a known Alcalase level of 0.07% in Savinase, 26% of Alcalase-sensitized subjects could react to Savinase. An excellent correlation (r > 0.97) was found between log concentration of antigen and wheal size parameters, with the log diameter and log area performing equally as well (r > 0.98). Analysis of variance revealed that more than 60% of intragroup variation represented human variability in wheal parameters at each concentration tested, whereas at least 95% of intergroup variation was due to regression. The excellent correlations of both wheal diameter and area with antigen concentrations were attributed to the very small changes observed between test concentrations.