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The crop is a known source of Salmonella and Campylobacter contamination. We evaluated the use of selected organic acids (0.5% acetic, lactic, or formic) in drinking water during a simulated 8-h pretransport feed withdrawal (FW). Salmonella typhimurium was recovered from 53/100 control crops and from 45/100 of crops from acetic acid-treated broilers. However, treatment with lactic acid (31/100) or formic acid (28/76) caused significant (P < 0.05) reduction in incidence. Reductions of recovered incidence were also associated with reduced numbers of S. typhimurium recovered (e.g., control, log 1.45 cfu/crop; lactic acid, 0.79 cfu/crop). In an additional commercial farm study, broilers were provided 0.44% lactic acid during a 10-h FW (4 h on the farm and 6 h transport) and pre-FW crop, post-FW crop, and pre-chill carcass wash samples were collected for Campylobacter and Salmonella detection. Crop contamination with Salmonella was significantly reduced by lactic acid treatment (6/175) as compared with controls (29/175). Importantly, Salmonella isolation incidence in prechill carcass rinses was significantly reduced by 52.4% with the use of lactic acid (26/175 vs. 55/176). Crop contamination with Campylobacter was significantly reduced by lactic acid treatment (62.3%) as compared with the controls (85.1%). Lactic acid also reduced the incidence of Campylobacter found on pre-chill carcass rinses by 14.7% compared with the controls. These studies suggest that incorporation of lactic acid in the drinking water during pretransport FW may reduce Salmonella and Campylobacter contamination of crops and broiler carcasses at processing.

Screening of poultry flocks for foodborne pathogen Salmonella contamination is critical for Salmonella control in preharvest stages of poultry production. In this study, two sampling methods (litter and air filter) were compared for detection of S. typhimurium from experimentally infected chicks some of which had received either a probiotic competitive exclusion culture or transfer of cecal contents from salmonellae-free adult birds. At 4, 9, and 11 days after inoculation, S. typhimurium samples were enumerated by selective plating. For both types of sampling, the control birds yielded the greatest levels of environmental contamination followed by the samples from the probiotic inoculated birds with the birds receiving the cecal transfer culture having the lowest levels of contamination. Although the two sampling methods responded in a similar fashion, detection sensitivity needs to be increased for air filter sampling.

Recent studies have indicated that crop contamination increases during preslaughter feed withdrawal and that contaminated crop contents may serve as an important source of Salmonella entry into poultry processing plants. During the present study, we evaluated the effect of preslaughter feed withdrawal on crop pH and Salmonella crop contamination in broilers from three commercial broiler flocks. The effect of experimental feed withdrawal on crop pH, lactic acid concentration, and Salmonella crop contamination was also evaluated in market-age broilers challenged experimentally with Salmonella typhimurium. Crop pH increased significantly (P < 0.05) from 3.64 +/- 0.25 before feed removal to 5.14 +/- 0.72 after 8 hr of feed withdrawal in broilers from commercial flocks. The incidence of Salmonella crop contamination in the commercial broilers increased (P < 0.05) from 3.3% before feed removal to 12.6% after 8 hr of feed withdrawal. Similarly, crop pH increased (P < 0.05) by a magnitude of approximately 1 unit in broilers after 8 hr of experimental feed withdrawal. The population of S. typhimurium in the crops of the experimentally challenged broilers increased (P < 0.05) by approximately 1 log unit during the 8-hr experimental feed withdrawal. The concentration of lactic acid in the crop of the broilers during experimental feed withdrawal decreased (P < 0.01) from a range of 119-135 mumol/ml before feed removal to a range of 22-32 mumol/ml after 8 hr of feed withdrawal. The results indicated that feed withdrawal resulted in a decrease in lactic acid in the crop, accompanied by an increase in crop pH, and an increase in Salmonella crop contamination.

Leghorn hens over 50 weeks of age were assigned to two treatment groups designated as either unmolted controls or molted. A forced molt was induced by a 9-day feed withdrawal, and each hen was challenged orally with 10(5) Salmonella enteritidis organisms on day 4 of feed withdrawal. On days 4 and 9 of molt, the numbers of lactobacilli and the concentrations of lactate, acetate, propionate, and butyrate, and total volatile fatty acids in the crops decreased while crop pH increased significantly (P < 0.05) in the molted hens compared to the controls. S. enteritidis crop and cecal colonization, in addition to spleen and liver invasion, increased significantly (P < 0.05) in the molted hens compared to the controls. The invasive phenotype of Salmonella spp. is complex and requires several virulence genes which are regulated by the transcriptional activator HilA. Samples of the crop contents from the molted and unmolted birds were pooled separately, centrifuged, and filter sterilized. The sterile crop contents were then used to measure the expression of hilA. By using a lacZY transcriptional fusion to the hilA gene in S. enteritidis, we found that hilA expression was 1.6- to 2.1-fold higher in the crop contents from molted birds than in those from control birds in vitro. The results of the study suggest that the changes in the microenvironment of the crop caused by feed deprivation are important regulators of S. enteritidis survival and influence the susceptibility of molted hens to S. enteritidis infections. Furthermore, our in vitro results on the expression of hilA suggest that the change in crop environment during feed withdrawal has the potential to significantly affect virulence by increasing the expression of genes necessary for intestinal invasion.

We analyzed risk of recurrence of supraventricular tachycardia (SVT) in 70 pediatric patients using both Kaplan-Meier survival analysis and logistic regression of likelihood of recurrence, each with covariates: (1) age at onset of SVT; (2) presence of Wolff-Parkinson-White syndrome (WPW), and (3) gender. Among 38 patients who had onset of SVT <1 year, only 11 had a recurrence, while among 32 older patients, 30 had a recurrence of SVT (p < 0.00001, Fisher's exact test). The survival analyses, stratified by age at onset <1 versus >1 year, were significantly different (p < 0.0001) as was stratification by presence of WPW (p < 0.01). Logistic regression analysis showed that the only significant predictor of recurrence was age at onset; the additional information provided by presence of WPW and gender did not significantly add to the prediction of recurrence. The odds ratio of recurrence for age at onset >1 versus <1 year was 34.6, with a 95% confidence interval of 6.98-172.

By conventional trayliner (hatcheries) and drag swab assembly (broiler houses) culture methods, the isolation distribution of Salmonella serotypes from five commercial broiler hatcheries (three sample times) and 13 broiler farms (eight sample times) was evaluated. A total of 11 different Salmonella serotypes were isolated from hatcheries, with Salmonella heidelberg (9/30) and Salmonella kentucky (6/30) accounting for 50% of the total isolations. Of 700 chick paperpad trayliners sampled, regardless of lot (breeder flock source) or hatchery, 12% were positive for Salmonella. When 10 individual trayliners were cultured from individual lots (same breeder flock source), Salmonella was detected in 24/57 lots (42%). Multiple serotypes were simultaneously isolated from the same lot on three occasions (6%). Of the 21 lots that were serially sampled, the Salmonella serotype detected was different within lots eight times (38%) on at least one occasion of two or more sampling times. Of the 196 individual broiler houses sampled, 44 were positive for Salmonella (42%). Twelve different serotypes were isolated from broiler houses during this study. The serotypes isolated most frequently were S. heidelberg (34/94) and S. kentucky (22/94). These two serotypes accounted for 59.6% (56/94) of the total broiler house isolations. Of the 38 houses that were serially sampled, two or more serotypes were detected in the same broiler house on 20 occasions (53%). Of the 38 serially sampled houses (four or more times), a consistent Salmonella serotype was detected in five houses (13%). In only 5 of the 38 (13%) serially sampled houses did we fail to detect Salmonella on four or more samplings. No significant difference in Salmonella isolation frequency was observed between poultry houses using new or used litter. These data support previous findings indicating that paratyphoid Salmonella serotypes are prevalent in some broiler hatcheries and houses. Further, the observation of multiple serotypes simultaneously and serially isolated from the same breeder hatchery lots suggests that breeder flocks may be infected with more than one serotype, possibly providing a source for multiple serotype infections in progeny grower flocks.

The presence of Campylobacter and Salmonella on poultry meat products remains a significant public health concern. Previous research has indicated that feed withdrawal may significantly increase Salmonella contamination of broiler crops and that crop contents may serve as an important source of Salmonella carcass contamination at commercial processing. The present study evaluated the effect of preslaughter feed withdrawal on the incidence of Campylobacter isolation in crops of market-age commercial broiler chickens prior to capture and transport to the processing plant. The incidence of Campylobacter isolation from the crop was determined immediately before and after feed withdrawal in 40 7-wk-old broiler chickens obtained from each of nine separate broiler houses. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. Feed withdrawal caused a significant (P < 0.025) increase in Campylobacter-positive crop samples in seven of the nine houses sampled. Furthermore, the total number of Campylobacter-positive crops increased significantly (P < 0.001) from 90/360 (25%) before feed removal to 224/359 (62.4%) after the feed withdrawal period. Alternatively, feed withdrawal did not significantly alter the Campylobacter isolation frequency from ceca. Similar to our previous studies with Salmonella, the present results suggest that preharvest feed withdrawal increases the frequency of Campylobacter crop contamination and, thus, provides a source of Campylobacter contamination of carcasses at commercial processing.

Previous research has identified cecal and intestinal contents as sources for Campylobacter contamination of broiler carcasses in the processing plant. During the present study, we evaluated the crop contents of preharvest market-age broilers as a potential reservoir of field-derived Campylobacter in the processing plant. Crops were collected aseptically from 40 randomly selected market-age broilers in each of nine commercial broiler flocks. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. The presence of Campylobacter in the crops and ceca was determined by enrichment culture in Bolton broth followed by culture on Campy-Ceflex plates. Campylobacter was isolated from the crop contents of broilers in seven of the nine flocks and from the cecal contents in three of six flocks. The incidence of Campylobacter-positive crop samples among all birds evaluated (224/359; 62%) was significantly higher (P < 0.001) than the number of positive cecal samples (9/240; 4%). The results indicate that the incidence of Campylobacter contamination of crop contents may exceed that of the cecal contents by as much as 37-fold in some broiler flocks, and may represent a critical preprocessing control point in reducing Campylobacter entry into the processing plant.

Several sampling methods have been developed for the detection of Salmonella on broiler carcasses during commercial processing. The present study evaluated three sampling methodologies for sensitivity of Salmonella detection on processed broiler carcasses. Furthermore, the effect of crop removal or chill tank exposure on the frequency of Salmonella recovery was also examined. In two experiments, swab, skin, and carcass rinse samples were compared for sensitivity of Salmonella detection. The results indicated that culture of swabs was less effective (P < 0.05) for Salmonella detection than either skin or carcass rinse samples. No significant (P > 0.05) differences were observed in Salmonella recovery from culture of skin or carcass rinse. In two subsequent experiments, skin and carcass rinse samples were found to be equally sensitive in their ability to detect Salmonella. Additionally, the stages of processing between feather and crop removal were observed to cause significant (P < 0.05) increases in Salmonella recovery within an individual flock. Similar increases (P < 0.05) in Salmonella recovery were also observed following crop removal and immediately following immersion chilling in two separate flocks. These results suggest that culture of skin samples obtained from the thoracic inlet region may be a viable alternative to the traditional whole carcass rinse method for sensitivity of Salmonella detection. Furthermore, these experiments provided some evidence that the majority of Salmonella cross-contamination of carcasses prior to immersion chilling occurred following evisceration, with the chill tank potentially providing a major site for cross-contamination between Salmonella-negative and-positive flocks.

Broiler chicks were spray treated on the day of hatch with titrated dosages (10(6), 10(7), or 10(8) anaerobic CFU) of a characterized competitive exclusion culture (CF3) and challenged orally on day 3 with 10(4) CFU of Salmonella typhimurium. On day 10, cecal contents from control and CF3-treated chicks were cultured for S. typhimurium to determine the minimal efficacious dosage of the CF3 culture. The experiment was repeated in three replicated trials. Resistance to Salmonella cecal colonization was dosage related and progressively enhanced at the 10(7)- and 10(8)-CFU dosages compared with the 10(6)-CFU dosage. The 10(7)-CFU dosage was selected as the minimal effective dosage and evaluated for efficacy during a 43-day broiler growout study. Six hundred broilers were spray treated on the day of hatch and compared with 600 controls. One-half of the control and CF3-treated birds were challenged orally on day 3 with 10(4) CFU of S. typhimurium and designated "seeders." The remaining unchallenged birds were designated "contacts." Compared with the controls, the recovery of Salmonella cells from the ceca of the CF3-treated broilers was significantly decreased (P < 0.01) in the challenged seeders on days 21 and 43 of growout. Salmonella contamination of floor pen litter was significantly reduced (P < 0.05) in pens of CF3-treated birds compared with controls. The transmission of Salmonella cells from seeder to contact birds in the same pens was decreased significantly (P < 0.01). The results indicated that treatment of broiler chicks on the day of hatch with the 10(7)-CFU dosage of CF3 culture effectively increased resistance to S. typhimurium challenge during growout to market age.

Day-of-hatch Leghorn chicks were treated by oral gavage with PREEMPT, a continuous-flow competitive exclusion culture containing broiler caecal bacteria, followed by an oral challenge with Listeria monocytogenes, to determine the effects of PREEMPT on L. monocytogenes caecal colonization. Increased (P < 0.001) concentrations of caecal propionic acid in control chicks compared with PREEMPT-treated chicks at 3 days of age were indicative of the establishment of the PREEMPT bacteria. Caeca from control chicks at 7 days after the oral challenge with L. monocytogenes contained mean 3.4 +/- 1.4 log cfu g-1 of caecal content, while caeca from PREEMPT-treated chicks contained no detectable Listeria. Enrichment for L. monocytogenes resulted in 100% of caeca from control chicks testing culture-positive for L. monocytogenes, while none of the caeca from PREEMPT-treated chicks were culture-positive. The results indicated that prophylactic treatment of newly hatched chicks with PREEMPT significantly reduced caecal colonization by L. monocytogenes.

Three surveys were conducted during November 1995 and March and May 1996 to compare the use of double-strength skim milk (wet) or no transport media (dry) drag swabs for the detection of salmonellae in 10 broiler houses. Salmonellae were isolated from 57 of 120 individual wet drag-swab samples, compared with 21 of 120 dry drag-swab samples. Furthermore, Salmonella was detected at a higher frequency with wet drag swabs (66.7%) than with dry drag swabs (40%) when compared on an individual growout house basis. A total of seven different serotypes were isolated from the 10 broiler houses. Although double-strength skim milk drag swabs are more labor intensive than dry drag swabs, double-strength skim milk drag swabs are more efficient for detecting Salmonella than are dry drag swabs with no transport media.

A competitive-exclusion culture was isolated by the continuous-flow culture of chicken cecal bacteria. The original continuous-flow culture and a continuous-flow culture derived from a lyophilized sample of it that had been stored for 180 days at -70°C were provided to day-old chicks. Experiments utilizing the original culture were performed after 5, 30, 100, and 365 days of continuous-flow conditions and the lyophilized culture after 5 days of continuous-flow culture. In all experiments chicks were challenged with 10 4 CFU of Salmonella typhimurium at 3 days of age. At 10 days of age the chicks were killed and cecal contents analyzed for fermentation parameters and for S. typhumurium colonization. Ten-day-old chicks provided with the original or the lyophilized culture had significantly increased cecal propionic acid ( P < 0.05) and decreased Salmonella cecal colonization ( P < 0.05) compared to untreated controls in all experiments. The results indicate that continuous-flow cultures can be used as a practical method to maintain competetive-exclusion cultures without loss of efficacy, and continuous-flow cultures stored in a lyophilized form can be reconstituted and still maintain efficacy.

Previous studies from our laboratory have demonstrated that bursal anti-steroidogenic peptide (BASP) inhibits progesterone biosynthesis from ovine luteinizing hormone-stimulated chicken ovarian granulosa cells. In the present investigation, we evaluated the efficacy of BASP for reducing cortisol secretion from normal canine adrenocortical cells and neoplastic adrenocortical cells from a dog with Cushing's syndrome. Treatment of adrenocortical cells derived from either normal healthy dogs or a cushingoid dog with adrenocorticotropic hormone (ACTH; 0-10 nM) caused an approximately two-fold increase in cortisol production from both normal or tumor derived adrenocortical cells. Small but significant decreases (up to 34%) in cortisol production were observed from normal and tumor derived canine adrenocortical cells when exposed to increasing concentrations of BASP (0.0-0.15 bursal equivalents; BEQ). Incubation of adrenocortical carcinoma cells or normal adrenocortical cells with ACTH (0-10 nM) and BASP (0.0-0.15 BEQ) increased cyclic AMP formation up to 2.5-fold. Interestingly, BASP suppressed basal cortisol production from tumor derived adrenocortical cells to normal levels when compared to the basal cortisol levels from normal derived adrenocortisol cells. Data from the present studies indicate that BASP is capable of suppressing basal and ACTH-stimulated cortisol production from normal or tumor derived adrenocortical cells in vitro. The possible clinical efficacy of homologous canine BASP on canine adrenal function or chicken BASP in other species of animals remains to be evaluated.

Previously, we demonstrated that a peptide from chicken bursa of Fabricius, bursal anti-steroidogenic peptide (BASP), inhibited LH-stimulated progesterone biosynthesis by granulosa cells from the two largest preovulatory follicles of the chicken ovary. In the present study, we investigated the influence of follicular maturation on the ability of BASP to inhibit granulosa cell steroidogenesis. Granulosa cells from the largest (F1), third largest (F3), and fifth largest (F5), preovulatory follicles of the laying hen were exposed to BASP in the presence or absence of ovine LH, forskolin, or dibutyryl-cAMP (db-cAMP). BASP (0.125 or 0.25 bursal equivalents [BEQ]) suppressed basal progesterone production in F5, but not in F1 or F3, granulosa cells. BASP suppressed LH-stimulated progesterone production in F1, F3, and F5 granulosa cells in a concentration-dependent manner; however, the lowest level (0.06 BEQ) did not suppress progesterone production in F5 granulosa cells. All levels of BASP suppressed forskolin-stimulated progesterone production in F1 granulosa cells, but only the highest level (0.25 BEQ) inhibited forskolin-stimulated steroidogenesis in F3 and F5 granulosa cells. Similar results were obtained with db-cAMP-stimulated granulosa cells. The inhibitory effects of BASP on F1, F3, and F5 granulosa cells were directly compared on a percentage basis. In the presence of each secret-agogue, the lowest level (0.06 BEQ) of BASP effectively suppressed progesterone synthesis in F1 and F3 but not F5 granulosa cells. At higher levels, there was no consistent difference in the ability of BASP to suppress stimulated progesterone production in granulosa cells at different stages of maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

We have previously reported that a peptide from chicken bursa of Fabricius, bursal antisteroidogenic peptide (BASP), inhibits luteinizing hormone-stimulated progesterone biosynthesis by chicken ovarian granulosa cells. The objective of this study was to determine the site(s) of BASP inhibition within the steroidogenic pathway of chicken granulosa cells. The effects of BASP on key steroidogenic enzymes, including adenylyl cyclase (AC), phosphodiesterase, the cholesterol side-chain cleavage enzyme complex and 3 beta-hydroxysteroid dehydrogenase were determined. Luteinizing hormone (10 ng/tube) stimulated a fivefold increase in granulosa cell progesterone production that was inhibited by BASP (0.06, 0.12 or 0.25 bursal equivalents) in a dose-dependent manner. Luteinizing hormone stimulated a sixfold increase in cyclic 3',5'-adenosine monophosphate (cAMP) formation, and this increase was potentiated by BASP in a dose-dependent manner. In addition, BASP stimulated cAMP formation in the absence of luteinizing hormone without affecting progesterone production. The AC activator forskolin (0.1 mM) stimulated a 4.5-fold increase in progesterone synthesis, which was inhibited by BASP. In the presence of forskolin. BASP increased cAMP formation in a dose-dependent manner. A fivefold increase in progesterone synthesis induced by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (1.0 mM) was inhibited by BASP. In the presence of 3-isobutyl-1-methylxanthine, BASP increased cAMP formation in a dose-dependent manner. Finally, 22(R)-hydroxycholesterol (250, 500, 1,000, or 2,500 ng/tube) or pregnenolone (50, 100, 200, or 500 ng/tube) resulted in up to 15- or 10-fold increases in progesterone production, respectively. Increasing concentrations of BASP caused a dose-dependent suppression of the conversion of 22(R)-hydroxycholesterol, but not pregnenolone, to progesterone. The inhibition of steroidogenesis by BASP is not associated with reduced cAMP levels, and BASP appears to strongly stimulate AC activity. In addition, these findings suggest that BASP may limit the availability of progesterone precursors by inhibiting the activity of the cholesterol side-chain cleavage enzyme complex.

Utilizing avian, porcine and canine adrenocortical cells, we have examined the effect of bursal anti-steroidogenic peptide (BASP) on adrenocorticotropin (ACTH) and dibutyryl cyclic AMP (DB-cAMP)-stimulated corticosteroid and cAMP formation. BASP significantly (P < 0.05) suppressed corticosteroid production from adrenocortical cells derived from chickens, pigs and dogs. BASP significantly increased cAMP formation (up to 10-fold) in a dose-related manner. These findings suggest that BASP structure and activity may be conserved between chicken, porcine and canine species.

The surgical management of idiopathic thoracolumbar and lumbar scoliosis is complex because of the surgeon's desire to achieve curve correction while maintaining normal lumbar lordosis with as many distal mobile lumbar segments as possible. By doing so, the surgeon is able to maintain normal sagittal alignment and decrease the chance of degenerative lumbar spine disease below the scoliosis fusion. This article discusses the surgical treatment of the thoracolumbar and lumbar curve, and, it is hoped, provides a better understanding of this complex problem.

1. Utilizing hen granulosa cells from the two largest (F1 and F2) follicles, we have examined the effect of sodium ascorbate (AS) on luteinizing hormone (LH) stimulated progesterone (PR) biosynthesis. 2. In experiment 1, in vitro AS levels as 0.0, 0.2, 0.4 or 0.8 mM were permutated by LH concentrations of 0.0, 1, 10 or 100 ng/ml. 3. Combination of 0.4 or 0.8 mM AS with physiological LH concentrations significantly (P < 0.05) enhanced (up to 28%) PR production. 4. In experiment 2, levels of AS at 0.3 and 0.6 mM significantly increased (up to 29%) LH induced PR synthesis. 5. These findings suggest that AS may be associated with chicken steroidogenesis as has been indicated for mammalian species.

Phenomenological association of alterations of immune system function at the time of puberty (e.g. involution of the chicken bursa of Fabricius) has led to postulation that the humoral immune system may negatively affect the hypothalamo-adenohypophyseal-gonadal axis of the neonate. Presently, we examined the effect of an acidic aqueous bursa of Fabricius extract, derived from prepubescent chickens, on in vitro basal and LH-stimulated progesterone biosynthesis by isolated ovarian granulosa cells of the largest preovulatory chicken follicles (F1 and F2). Crude extracts of < 5kDa and > 3kDa inhibited LH-stimulated progesterone secretion (P < 0.05). The bioactive component was observed to be heat labile and is sensitive to the endopeptidases chymotrypsin, trypsin and papain. The peptide is not sensitive to the exopeptidase, aminopeptidase M. Partial purification by reversed phase HPLC resulted in a fraction capable of inhibiting in vitro steroidogenesis. This fraction suppressed LH-stimulated progesterone biosynthesis to approximately basal levels (79% suppression). Following removal of the peptide, granulosa cells were capable of LH-stimulated progesterone biosynthesis similar to control cells. Bursal extract significantly inhibited cAMP analog-stimulated progesterone biosynthesis. These data indicate that the anti-steroidogenic peptide derived from the chicken bursa of Fabricius is a single heat labile, amino terminally blocked peptide with bioactivity independent of the gonadotropin receptor of the granulosa cell.

Two transpedicular spinal instrumentation systems were developed for fixation of the lumbosacral junction: a transpedicular fixator and the transpedicular screw/rod system. Mechanical testing showed that the new systems have a rigidity that is intermediate between conventional wired implants (Galveston and Luque ring) and plate systems (Steffee plate). Neither pedicular implant approached the rigidity of the Steffee plate with S2 fixation, but in compression and anterior bending both were more rigid than the Steffee plate without S2 fixation. Despite the apparent mechanical advantages of the transpedicular fixator, it is currently too bulky for clinical use. The transpedicular screw/rod system is more appealing because the size leaves adequate area for bone grafting, and device placement is technically simple. Furthermore, it may be contoured to any plane, while retaining stability provided by the clamps and screws.

Two separate experiments were conducted to determine the ability of magnesium aspartate hydrochloride (Mg-Asp-HCl) to antagonize the effects of thermal stress in laying hens. In both experiments, hens were exposed to either a cyclic ambient temperature of 27 C to 35 C (hyperthermic group) or 23 C (control group) for 7 days. In Experiment 1, hens were given a single injection of either saline, 40 mg, or 80 mg Mg-Asp-HCl. Experiment 2 hens received a single injection of saline, 40 mg Mg-Asp-HCl, or twice daily injection of 40 mg Mg-Asp-HCl. In both experiments, heat-stressed hens had elevated body temperature and reduced body weight, feed consumption, and circulating mean Mg concentrations. Hyperthermic hens also had reduced egg weights in Experiment 1. A single daily injection of 40 mg of Mg-Asp-HCl significantly reduced body weight loss in heat stressed hens by 41 and 51%, in Experiment 1 and 2, respectively, when compared with heat-stressed hens not receiving Mg-Asp-HCl (controls). The Mg-Asp-HCl treatment did not affect overall feed intake, egg production, or body temperature in either experiment. The highest dose of Mg-Asp-HCl (80 mg) elevated circulating magnesium concentrations. A single daily injection of 80 mg of Mg-Asp-HCl or twice daily injections of 40 mg Mg-Asp-HCl did not provide any additional benefit when compared with a single daily dose of 40 mg. The antistress effects of Mg-Asp-HCl are apparent in these experiments as evidenced by the increased body weight of heat-stressed hens. Use of this compound may prove to be beneficial in maintaining the performance characteristics of poultry exposed to elevated ambient temperature.

During surgical correction of scoliosis, 63 patients had somatosensory evoked potential (SEP) monitoring of the spinal cord. Tibial nerves were unilaterally stimulated, and the potentials were recorded from the midcervical spine with surface and epidural needle electrodes. Over 85% had no significant change in their SEP and no postoperative neurologic deficits. Eleven percent had a significant change in their potential (amplitude decrease of greater than 60% and/or latency increase of greater than 2.5 msec) with no neurologic complications. One patient had a significant potential change and temporary postoperative sensory deficits did occur. One additional patient experienced postoperative neurologic complications but had no SEP change. This single false negative case, however, was clinically significant only for motor dysfunction, which is not monitored by the SEP. When changes in patient core temperature were compared to changes in SEP amplitude and latency, an intraoperative decrease in core temperature increased SEP latency and decreased amplitude, which may explain in part the false positive rate of the procedure.

Twenty-six adults, ranging in age from nineteen to fifty-eight years old, were treated for idiopathic scoliosis by two-stage anterior and posterior spinal fusion. The goals of the combined procedure were to increase correction of the curve and decrease the rate of pseudarthrosis. Preoperatively, the major curves measured an average of 83 degrees, and on the best side-bend they averaged 59 degrees, a 29 per cent degree of flexibility. At the time of discharge from the hospital the curves had improved to an average of 44 degrees, a correction of the preoperative curve of 39 degrees or 47 per cent. At an average length of follow-up of forty-nine months, the major curves measured an average of 50 degrees, a 41 per cent correction compared with the initial curves. Twenty-three of the major curves were better than when they were measured on the preoperative radiograph of the best side-bend, by an average of 15 degrees, but eight curves were either the same or worse. No patient had pseudarthrosis or permanent neurological injury. It is our conclusion that a two-stage anterior and posterior fusion is of value for the treatment of the adult who has a rigid curve that requires maximum correction to allow the head, shoulders, and torso to be centered over the pelvis. We do not recommend the use of instrumentation for the anterior fusion as this did not increase the correction of the curve in this series of patients.