A descriptive survey of lesions from cull sows harvested at two Midwestern U.S. facilities

Physical and reproductive conditions of cull sows (3158) from two U.S. Midwestern harvest plants were assessed. Body condition, feet, shoulders, teeth, lungs, and reproductive tracts were visually evaluated for gross lesions on harvested sows. PROC FREQ (SAS, Cary, NC) was used to calculate the frequency of each binary trait event. Pearson chi-square tests were used to test the alternative hypothesis that a linear association existed between binary traits and body condition score (BCS). The most common foot lesions observed were rear (n=2064, 67.5%) and front (n=1024, 32.9%) heel lesions. Cracked hooves were found on the front feet of 703 (22.6%) and rear feet of 552 (18.1%) sows. Rear digital overgrowth was observed in 644 (21.1%) sows. The most common reproductive gross lesion observed among harvested cull sows was acyclic ovaries (n=277, 9.0%). Presence of acyclic ovaries increased (p<0.01) as BCS decreased. Cystic ovaries were found in 192 (6.3%) sows, which increased (p<0.01) as BCS increased. Pneumonia was observed in 298 (9.7%) sows, and increased in frequency as BCS decreased (p<0.01). The most frequently observed shoulder lesion among harvested cull sows was shoulder abrasions (n=394, 12.5%). The presence of shoulder abrasions increased (p<0.01) as BCS decreased. The prevalence of reproductive lesions detected in the present study was less than the reported percentage of sows culled for reproductive failure from previous studies based on record keeping summaries.

Quantity and distribution of Salmonella recovered from three swine lairage pens

The quantity of Salmonella recoverable from three lairage pens in a swine abattoir was determined. Using dry four-ply cotton gauze pads measuring 10 by 10 cm, 100 fecal slurry samples were collected from each of the three pens. Salmonella recovery was expressed as the log CFU per milliliter of sample. Mean values were 2.5 log CFU/ml in pen A, 2.7 log CFU/ ml in pen B, and 0.89 log CFU/ml in pen C. Median values were 2.6 log CFU/ml in pen A, 2.0 log CFU/ml in pen B, and below the detectable limit in pen C. In pen C, Salmonella was not recoverable from a high number of samples. Pen B results suggested spatial dependency, i.e., samples close together were more similar than samples farther apart. These results indicate that Salmonella concentrations vary within and between lairage pens. Because of the limited number of pens assessed, it was not possible to identify factors that were associated with the observed variation in Salmonella concentrations within and between pens. However, this variation suggests that numeroussamples are required to adequately describe the concentration of Salmonella in a lairage pen.

Variable abattoir conditions affect Salmonella enterica prevalence and meat quality in swine and pork

Research suggests that abattoir holding pens pose significant Salmonella enterica risk to swine immediately preharvest. The goal of this study was to evaluate those factors related to holding that increased the prevalence of S. enterica in swine at slaughter. To accomplish this goal, we focused on holding time and flooring. Our objectives were to (1) compare Salmonella enterica prevalence among pigs held for short (15-45 min) versus long (up to 4 h) periods before slaughter; and (2) determine the impact of flooring (slatted vs. concrete) as it relates to the prevalence of S. enterica. The study consisted of seven repetitions at a large volume (11,000 head/day) Midwest abattoir. Each repetition consisted of one truck load of pigs (n = 170) sorted into one of three groups: (1) animals held for a short time (15-45 min) on solid floors (short-hold); (2) animals held for 4 +/- 0.5 h on slatted floors; and (3) animals held for 4 +/- 0.5 h on solid concrete floors. At slaughter, samples were collected from 30 pigs in each group. Cecal contents (20 mL), feces (20 g), and the ileocecal lymph node were cultured for S. enterica. Additionally, the effect of holding time on meat quality parameters (loin pH at 35 min and 6 h, color, drip loss) was evaluated for the first four replicates. The proportion of S. enterica-positive samples was highest (p < 0.05) in the cecum of pigs held on solid concrete floors (72.4%), and slightly less for pigs held on slatted floors (63.3%). Animals held for less than 45 min before slaughter demonstrated the lowest proportion of S. enterica-positive samples (52.9%). The pig prevalence, as measured by any one of the three samples being positive, was significantly different (p < 0.05) between animals held on solid floors (81%) and those animals held for 45 min or less before slaughter (69%). Meat quality, as measured by multiple parameters, was adversely affected by lack of a rest period. The mean 24-h pH was significantly lower for the short-hold group compared to the other two groups. The mean Minolta L and the drip loss were significantly higher in the short-hold group. From this and other studies, it appears that elimination of the holding process is not feasible S. enterica control option, given current U.S. harvesting systems.

Effect of short-term lairage on the prevalence of Salmonella enterica in cull sows

This study was designed to compare Salmonella enterica prevalence in sows held in a holding pen at the abattoir for approximately 2 h (hold sows) with sows slaughtered immediately after transport to the abattoir (no-hold sows). Cull sows (n = 160) were sampled from four sampling periods over 8 weeks (February to March 2002) at the abattoir. Sows originated from an integrated swine farm and were sent to a live-hog market and then to the slaughter facility. Before testing, sows entered the abattoir pen and four 100-cm2 four-ply gauze squares were placed randomly on the pen floor for S. enterica culture. Sows were alternatively assigned to the hold or no-hold group. Samples collected from sows during slaughter were ileocecal lymph node, cecal contents, transverse colon contents, subiliac lymph node, sponge swabs of the left and right carcass section (300 cm2), and chopped meat. Overall, S. enterica was isolated from 44% (35 of 80) of the no-hold sows, which was significantly less (P < 0.05) than 59% (47 of 80) of the held sows. Also, no-hold sows had a lower cecal content prevalence (39%, 31 of 80) compared with that (55%, 44 of 80) of held sows (P < 0.05). S. enterica serovars isolated from no-hold sows were Brandenburg (n = 16), Derby (n = 12), Hadar (n = 8), Infantis (n = 6), Johannesburg (n = 3), 6,7:z10-monophasic (n = 3), and Typhimurium (n = 1). S. enterica serovars isolated from held sows (n = 61 isolates) were Derby (n = 19), 6,7: z10-monophasic (n = 15), Brandenburg (n = 10), Infantis (n = 6), Hadar (n = 5), Johannesburg (n = 4), and Tennessee (n = 2). Serovars recovered from the pen were Reading (n = 6), Derby (n = 4), Uganda (n = 2), and Manhattan (n = 2). Results of this study suggest that holding pens contribute to increased S. enterica carriage in cull sows. Abattoir holding pens might be an important control point for S. enterica in the ground pork production chain.

Estimation of the Salmonella enterica prevalence in finishing swine

The study objective was to evaluate three methods of Salmonella enterica prevalence estimation in swine herds (faecal culture, culture of abattoir-collected samples, and serum ELISA). From each of six swine herds, we necropsied approximately 100 finishing pigs (> 70 kg); one-half on farm and the other half at the abattoir, after transport and approximately 2.5 h holding. We collected the same samples for S. enterica culture at both locations (1 g faecal, 10 g caecal contents, ileocaecal lymph nodes, superficial inguinal lymph nodes, 25 g of gluteal muscle for serum ELISA). On farm, the 1 g faecal sample only detected 13.3% (2/15) of all positive pigs necropsied on farm. However, with abattoir and on-farm results combined, the faecal sample detected 57.4% (74/129) of positive pigs. Abattoir-collected samples provided prevalence estimates much higher than on-farm collected samples (39.9 vs. 5.3%; P < 0.001). This study shows that faecal samples have a low sensitivity for detecting infected pigs and that abattoir-collected samples overestimate the on-farm S. enterica prevalence. For most herds, serology overestimated the on-farm culture prevalence.

Preslaughter holding environment in pork plants is highly contaminated with Salmonella enterica

The objective of this study was to determine whether abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of preharvest holding. Previous work has suggested that pigs may be getting infected, but little has been reported on the environmental contamination of abattoir holding pens. For 24 groups of pigs studied ( approximately 150 animals/group) at two high-capacity abattoirs, six pooled fecal samples (n, 10 per pool) were collected from each transport trailer immediately after pigs were unloaded. Holding pens were sampled (one drinking water sample and six pooled floor samples consisting of swabs, residual liquid, and feces) prior to entry of study pigs for the routine holding period ( approximately 2.5 h). After slaughter, cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of S. enterica by primary enrichment in GN-Hajna and tetrathionate broths, secondary enrichment in Rappaport-Vassiliadis broth, and plating on brilliant green sulfa and xylose-lysine-tergitol-4 agars, followed by biochemical and serological identification. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive for S. enterica. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates from pigs (109 from ileocecal lymph nodes plus 244 from cecal contents), 19% were identified as belonging to the same serovars as those isolated from the respective pens; 27% were identified as belonging to the same serovars as those isolated from the trailers. Sixteen percent of the unique serovars were isolated from both pigs and pens, suggesting that pens served as the infection source. This study demonstrates highly contaminated abattoir holding pens and watering sources. It also demonstrates that holding pens can serve as an infection source. This study identifies the abattoir holding pens as a significant hazard and a potential control point for Salmonella contamination in the preharvest pork production chain.

Impact of commercial preharvest transportation and holding on the prevalence of Salmonella enterica in cull sows

The objective of this study was to examine the prevalence of Salmonella enterica in cull sows at various stages from the farm to the abattoir. Cull sows (n=181) were sampled over 10 weeks. Fecal samples (10 g each) were collected on the farm ca. 24 h before loading and at the live-hog market ca. 3 h before loading. Samples (ileocecal lymph nodes, cecal contents, feces from the transverse colon, ventral thoracic lymph nodes, subiliac lymph nodes, sponge swabs of the left and right carcass sections, and chopped meat) were collected at the abattoir. The percentages of positive fecal samples on the farm and at the live-hog market were 3% (5 of 181 samples) and 2% (3 of 181 samples), respectively. After transport from the live-hog market (10 h) and holding at the abattoir (6 h), 41% (74 of 180) of cull sows yielded S. enterica in one or more sampled tissues. The isolation rate for total cecal contents (33%; 60 of 180 samples) was significantly (P<0.05) higher than those for ileocecal lymph nodes (7%; 12 of 181 samples), feces (11%; 20 of 181 samples), and ventral thoracic and subiliac lymph nodes (2%; 4 of 181 samples). Before a 2% lactic acid carcass wash (lasting 8 to 9 s), 14% (25 of 180) of carcasses were positive, compared with 7% (12 of 179) after the wash (P<0.05). Two S. enterica serotypes, Derby and Infantis, were found on the farm and at the live-hog market. At the abattoir, 12 serotypes that had not previously been found on the farm or at the live-hog market were recovered. The results of this study demonstrate that transport and holding practices may contribute to an increase in S. enterica infection prior to slaughter to levels much higher than those found on the farm.

Salmonella enterica infections in market swine with and without transport and holding

The objective of this study was to compare, by using identical sample types, the Salmonella enterica prevalences and serovar diversities between pigs necropsied on the farm and those necropsied at the abattoir after transport and holding. We necropsied 567 market weight pigs (>70 kg) from six herds. Pigs were alternately assigned to be necropsied on the farm or at the abattoir. One-half of the group was sent in clean, disinfected trailers to slaughter at a commercial abattoir. After transport (mean distance, 169 km) and 2 to 3 h of holding in antemortem pens, these pigs were necropsied. The 50 pigs remaining on the farm were necropsied the following day. The same sample types and amounts were collected for S. enterica culture at both locations. Results show a sevenfold-higher (P < 0.001) S. enterica isolation rate from pigs necropsied at the abattoir (39.9%; 114 of 286) than from those necropsied on the farm (5.3%; 15 of 281). This difference was also observed for each individual herd. All sample types showed a significantly higher prevalence when comparing abattoir to on-farm collection, respectively: lymph nodes, 9.15 versus 3.6%; cecal contents, 13.6 versus 1.8%; 1 g of fecal matter, 25.2 versus 0.7%. Recovery of additional serovars at the abattoir suggests the pigs are receiving S. enterica from extra-farm sources. This study demonstrates that rapid infection during transport, and particularly during holding, is a major reason for increased S. enterica prevalence in swine. This finding identifies the holding pen as an important S. enterica control point in the pork production chain.

Pathology and neuroimaging in pediatric temporal lobectomy for intractable epilepsy

OBJECTIVES

Firstly, to study the pathology at surgery in children undergoing temporal lobectomy for intractable partial epilepsy. Secondly, to compare neuroimaging techniques (CT, MRI) in the preoperative detection of pathology. Lastly, to examine the surgical outcome in children.

METHODS

Forty-two pediatric patients undergoing temporal lobectomy for intractable epilepsy at the Comprehensive Epilepsy Program at the University of Alberta Hospital between the years 1988-1998 were studied. Patients had extensive preoperative investigations including CT and MRI. The pathology at surgery was reviewed and compared to preoperative neuroimaging. Charts were reviewed to determine surgical outcome.

RESULTS

Brain tumors were the most common pathology, found in 13/42 patients. Mesial temporal sclerosis (MTS) was found in 8 patients and dual pathology in an additional 5. Focal cortical dysplasia (FCD) was seen in 4 patients, 1 patient had a porencephalic cyst and 4 patients had tubers of tuberous sclerosis. Seven patients had no specific pathology detected. MRI was clearly more sensitive than CT in the detection of pathology. MRI was abnormal in 27/42 cases (64%), while CT scan was found to be abnormal in only 12/39 (31%). Surgical outcome was excellent, with 34/42 patients (80%) having an Engel class I outcome. One patient had significant improvement with an Engel class II outcome, 3 (7%) had little improvement (Engel class III) and 4 (10%) were unchanged (Engel class IV). Three patients (7%) had surgical complications.

CONCLUSIONS

A wide variety of developmental pathology is seen following temporal lobectomy for intractable epilepsy of childhood. Brain tumors, FCD and MTS are common. MRI is superior to CT in the detection of pathology, which may be subtle in children. Surgical outcome is excellent, with most children being seizure free and few complications being seen.

Impact of commercial pre-harvest processes on the prevalence of Salmonella enterica in cull sows

This study examined the impact of transport and lairage on Salmonella enterica prevalence in cull sows held under commercial conditions. Five sampling periods over 10 weeks yielded 181 selected culls. Fecal sample positives at the farm and collection point were 2% and 3%, respectively. After transport and lairage 41% of cull sows yielded S. enterica in one or more sampled tissues. A significant increase in cecal isolations was observed. The two S. enterica serotypes found at the production site and collection point were found at the abattoir, as were 13 other serotypes. Transport and lairage practices may contribute to an increased S. enterica contamination immediately prior to slaughter.

Experimental rapid infection in market swine following exposure to a Salmonella contaminated environment

The objective of these experiments was to evaluate the possibility of swine becoming infected with Salmonella Typhimurium after a short time interval in a contaminated environment. Two experiments were conducted. Experiment 1 consisted of five trials with eight market weight swine. Pigs were necropsied at 2 (n = 10), 3 (n = 10) and 6 (n = 5) hours after continuous exposure to an environment contaminated with feces shed by swine intranasally inoculated with nalidixic acid-resistant Salmonella Typhimurium (chi 4232). In Experiment 2, pigs were necropsied after 30 minutes (n = 6), 60 minutes (n = 6), 2 hours (n = 6), and 6 hours (n = 3). In addition, control animals with no exposure were also necropsied in both experiments. At necropsy, the superficial inguinal, ileocecal, and mandibular lymph nodes, as well as cecal contents, distal ileum portion, and feces were evaluated. All samples were cultured for the presence of the nalidixic acid-resistant Salmonella. Feces deposited on the floor by intranasally inoculated swine were mixed with water to form slurry with a resulting load of 10(3)-10(5) Salmonella Typhimurium CFU per gram. In Experiment 1, 80% percent of animals with a 2-hour, 60% of animals with a 3-hour, and 100% of animals with a 6-hour exposure to this slurry had at least one sample test positive for the marked Salmonella Typhimurium strain. In Experiment 2, 50% of the 30 minute, 50% of the 60 minute, and 33% of the 2-hour exposed pigs had at least one sample test positive. These experiments show that market swine can become infected during routine resting or holding periods when exposed to relatively low levels (10(3) CFU) of Salmonella in the simulated pre-slaughter environment, and that exposure times as short as 30 minutes are sufficient to produce contaminated gastrointestinal tracts. They also demonstrate the high risk of holding pigs longer than six hours. Intervention at this step in the swine production process may have a significant impact on the safety of pork products.

Rapid infection in market-weight swine following exposure to a Salmonella typhimurium-contaminated environment

OBJECTIVE

To evaluate the possibility of swine becoming infected with Salmonella Typhimurium when housed for 2 to 6 hours in an environment contaminated with Salmonella, similar to a lairage situation prior to slaughter.

ANIMALS

40 crossbred market pigs with an approximate body weight of 92 kg.

PROCEDURE

Five trials were conducted (8 pigs/trial) in simulated lairage conditions. Superficial inguinal, ileocecal, and mandibular lymph nodes, cecal contents, distal portion of the ileum, and fecal samples were obtained from each pig after 2 (n = 10), 3 (10), and 6 (5) hours of exposure to an environment contaminated with feces defecated by 10 pigs intranasally inoculated with nalidixic acid-resistant Salmonella Typhimurium (chi4232). In addition, 5 control pigs that were not exposed were also evaluated in the same manner.

RESULTS

Feces deposited on the floor by intranasally inoculated swine were mixed with water to form slurry with a resulting load of approximately 10(3) colony-forming units of Salmonella Typhimurium/g of material. Eight of 10, 6 of 10, and 6 of 6 pigs exposed to the slurry for 2, 3, or 6 hours, respectively, had positive results for at least 1 sample when tested for the specific strain of Salmonella Typhimurium.

CONCLUSIONS AND CLINICAL RELEVANCE

Pigs can become infected during routine resting or holding periods during marketing when exposed to relatively low amounts of Salmonella organisms in the preslaughter environment. Intervention at this step of the production process may have a major impact on the safety of pork products.

The importance of traceability for public health and consumer protection

Since the 1980s, concerns about the safety and quality of food have increased at both governmental and consumer levels. The importance of traceability of animals and animal products has grown as food production and marketing have been removed from direct consumer control. Product traceability, which requires a transparent chain of custody to maintain credibility and to complete information transfer functions, has two components, namely: a unique identification system, and a credible and verifiable mechanism for identity preservation. Traceability systems can be subdivided into the following four categories: country of origin; retail; processor; and farm-to-retail identity. Although the availability of computers and electronic data devices can enhance the speed and accuracy of data acquisition and manipulation, a common set of developmental criteria exists, irrespective of data-handling processes. As data management technologies become more powerful and less costly, product traceability requirements will multiply. Public and private sectors should seize these opportunities to improve public health and quality parameters, or risk a narrowing of their markets.

The effect of lairage on Salmonella isolation from market swine

The objective of this paper was to evaluate the effect of lairage (holding >12 h during transport to slaughter) in clean facilities on Salmonella isolation from market swine. We tested 30 market-bound pigs (about 240 lb [110 kg]) on each of 10 occasions from an Iowa farrow-to-finish operation with about 600 sows. All pigs were slaughtered, and samples were collected at a large Midwest abattoir. On the farm, fecal samples were collected for culture of Salmonella. Pigs were alternately assigned to a lairage treatment (holding in a clean, disinfected facility at the National Animal Disease Center) group or a control group (remaining on the farm). After about 18 h, both groups were transported (about 137 km) to a large Midwest abattoir, commingled, and slaughtered. After slaughter, samples were collected for culture of Salmonella (feces from the distal colon, ileocecal lymph nodes, cecal contents, ventral thoracic lymph nodes, subiliac lymph nodes, and carcass swabs). Diaphragm sections were collected for serum ELISA. Salmonella enterica Derby was the only serotype isolated from farm fecal samples (3.4%, 10 of 290). Multiple serotypes (n = 17) were isolated from 71.8% (196 of 273) of the pigs when abattoir-collected samples were cultured: cecal contents (21.2%. 58 of 273), distal colon contents (52%, 142 of 273), and ileocecal lymph nodes (43.6%, 119 of 273). There were lower Salmonella isolation rates from the lairaged pigs (P < 0.05). The predominant serotype isolated at the abattoir varied by week of the study. This study suggests that pigs became internally contaminated with Salmonella after leaving the farm, possibly while in the abattoir holding pens, and that 18 h lairage, in clean facilities, does not increase shedding.

Survey of veterinary extension in the United States

OBJECTIVE

To assess veterinary extension in the United States as perceived by veterinary extension personnel.

DESIGN

Cross-sectional survey.

SAMPLE POPULATION

Extension veterinarians in the United States.

PROCEDURE

2 surveys were designed and mailed to extension veterinarians listed by the USDA and the American Association of Extension Veterinarians.

RESULTS

34 states had > or = 1 extension veterinarian. The majority (> 60%) of extension veterinarians did not commit time to resident education and were not involved in research activities. Paradoxically, 23% of responding extension veterinarians did not report extension work. Programs for food animal producers, horse owners, and companion animal owners were provided by 100, 63, and 37% of states, respectively. Continuing education (CE) programs were provided for food animal veterinarians, equine veterinarians, and companion animal veterinarians by 96, 63, and 52% of states, respectively. Challenges facing veterinary extension included limited recognition of veterinary extension activities by universities, lack of university personnel to support CE programs, and decreased support for companion animal extension programs.

CONCLUSIONS AND CLINICAL RELEVANCE

Extension veterinarians need to identify and clearly articulate the mission of veterinary extension, develop more collaborative programs across regions, and continue to serve as catalysts to bring diverse constituents together. Extension veterinarians must distinguish their mission not solely as information transfer, which can be accomplished in a variety of ways outside of extension, but as a coherent and consistent program of education and policy developed on a national level and distributed locally.

Prevalence of coronavirus antibodies in Iowa swine

Three hundred and forty-seven serum samples from 22 Iowa swine herds were screened for TGEV/PRCV neutralizing antibody. Ninety-one percent of the sera and all 22 herds were positive. These sera were then tested by the blocking ELISA test to distinguish TGEV and PRCV antibody. The ELISA test confirmed the high percentage of TGEV/PRCV positive sera. By the blocking ELISA test, 12 herds were PRCV positive, 6 herds were TGEV positive and 4 herds were mixed with sera either positive for TGEV or PRCV antibody. The results suggest a recent increase in TGEV/PRCV seroprevalence in Iowa swine most likely due to subclinical PRCV infections.

Glutathione levels and chemosensitizing effects of buthionine sulfoximine in human malignant glioma cells

Biopsy samples and cultured cells derived from them were obtained from 39 patients with malignant glioma and were analyzed for 1) glutathione (GSH) content; 2) sensitivity to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and/or nitrogen mustard (HN2) treatment and 3) the effect of buthionine sulfoximine (BSO) treatment on BCNU and/or HN2 cytotoxicity. The average GSH concentration of biopsy specimens was lower than those of cultured cells (2.36 +/- 0.44 vs. 11.42 +/- 2.32 nmol/10(6) cells). While some of the tumor specimens were sensitive to either BCNU or HN2, the majority were resistant to both. However, 8 of 23 tumors tested showed enhanced sensitivity to BCNU following treatment with BSO. Five of 17 tumors were similarly sensitized to HN2 by BSO. These results suggest that BSO chemosensitization may be of value for certain patients and that screening assays may help identify treatment-sensitive individuals.

Development of a large-animal human brain tumor xenograft model in immunosuppressed cats

A large-animal model was developed to facilitate the noninvasive investigation of the effect on the human glioma-derived D-54 MG (glioblastoma multiforme) continuous cell line of a variety of therapeutic regimens. Twenty random-bred male cats were inoculated intracerebrally with 1 x 10(7) D-54 MG tumor cells after being initiated on one of three preparatory regimens of cyclosporin A p.o. Reproducible success of D-54 MG xenotransplantation (100%, 6 of 6 cats) was achieved only after pretreatment with 120 mg cyclosporin A p.o. (24-30 mg/kg) daily for greater than or equal to 10 days prior to tumor implantation. High-performance liquid chromatography-derived whole blood cyclosporin A 12-h trough levels of greater than or equal to 640 ng/ml were seen in successful implants. Lesions ranging from 2 to 20 mm in diameter were seen in cats sacrificed 27-44 days after implantation with no growth seen in control animals. Histopathological examination revealed the tumors to be well-circumscribed anaplastic intracerebral tumors with some invasion into surrounding host parenchyma. Perivascular lymphocytic cuffing was observed, but intratumoral lymphocytic infiltration was minimal. Gadolinium-EDTA-enhanced nuclear magnetic resonance imaging provided accurate tumor localization in T1-weighted images (TE 26 ms; TR 600 ms). Biochemical tests of kidney, liver, and hematological function were within normal limits, although 10% (2 of 20) of the animals developed gingival hyperplasia, and 5% (1 of 20) developed intussusception. The reproducible growth of the D-54 MG human glioblastoma cell line in a large-animal model eliminates many of the limitations associated with the standard nude mouse/rat model, thereby providing a novel test bed for a variety of imaging modalities as well as for drug immunoconjugate localization and toxicity studies.

Absence of IFNA and IFNB genes from human malignant glioma cell lines and lack of correlation with cellular sensitivity to interferons

We report that 5 of 19 human malignant glioma cell lines have neither interferon alpha (IFNA) nor interferon beta (IFNB) genes that are detectable by Southern blotting. Of 5 other of these malignant glioma lines that have a single IFNB gene copy, 3 lack the IFNA genes entirely and two have one copy. One of the lines that lacks the IFNA genes entirely but has one copy of the IFNB gene has a rearrangement near the IFNB gene that is most easily interpreted as an insertion of a large segment of DNA (at least 50 kilobases) the 3' end of which is less than 1.3 kilobases 5' to the known regulatory sequences of the IFNB gene. In spite of the rearrangement, IFNB-specific RNA is highly inducible in this line by poly(I)-poly(C). The ability of interferon alpha or interferon beta to inhibit cell growth does not depend upon the presence or absence of the respective gene. This finding adds solid tumors to those tumor cell lines (acute lymphocytic leukemia, chronic myelogeneous leukemia) previously determined to lack the IFNA and IFNB genes (Diaz et al., Proc. Natl. Acad. Sci. USA, 85:5259-5263, 1988).

New long-wavelength Nd:YAG laser at 1.44 micron: effect on brain

A wavelength-shifted Nd:YAG laser, tuned to coincide with the infrared absorption peak of water at 1.44 microns, was used to make lesions in normal rabbit brain. A total of 48 lesions were made with power up to 20 W, with energy up to 40 joules, and with two different spot sizes. These lesions were compared to lesions made with 1.06 microns radiation from an Nd:YAG laser under identical operating conditions. Measurements of blood-brain barrier damage and width, depth, and volume of tissue affected were obtained 30 minutes after placement of the lesions. It was found that 1.44-microns lesions produced photoevaporative tissue loss at the highest intensities used. The layer of coagulated tissue remaining after photovaporization had a mean thickness of 0.6 mm irrespective of the volume of tissue removed. There was no photovaporization in the 1.06-microns lesions. In addition, the amount of peripheral edema per unit volume of tissue coagulated was approximately half at the 1.44-microns wavelength. These findings suggest that the 1.44-microns Nd:YAG laser may be a useful surgical instrument since it combines the photoevaporative effect of the CO2 laser while maintaining the advantages of the conventional Nd:YAG laser (quartz fiber delivery and effective hemostasis).

Effects of temporal lobectomy for treatment of epilepsy on hemispheric functions ipsilateral to surgery: preliminary findings

Several studies have reported a pattern of ipsilateral deficit and contralateral improvement following temporal lobectomy. Presumably the contralateral improvement is due to cessation of commissural spread, and the ipsilateral deficit to surgical damage to that side. If, as hypothesized, the underlying mechanism is cessation of commissural spread of seizure activity, some ipsilateral improvements might also occur. This question was addressed in a small sample of left (N = 4) and right (N = 5) temporal lobectomy patients. It was found that the left-operated patients demonstrated improvements on tests reported to measure left frontal lobe function. In addition, both left- and right-operated patients improved on a dexterity test with the hand ipsilateral to the side of surgery. The ipsilateral improvement would be due to removal of an active electrically discharging focus impairing ipsilateral function and contralateral function by commissural spread. These data were interpreted to suggest that cessation of commissural spread of seizure activity can result in improvement in regions of the hemisphere ipsilateral to surgery, and that the contralateral hemispheric improvements may include psychomotor functions in addition to memory and IQ changes. Seizure control achieved by surgery may have influenced the pattern of results.

CT guided functional stereotaxic surgery

One of the major problems in stereotaxic surgery is to identify the brain target. Since these do not show on any of the usual radiological studies they have to be located with reference to observable structures. Initially bony landmarks were used but later either positive or negative contrast ventriculograms were found to be more accurate. Often this involves additional needling of the brain or a spinal puncture with the added mortality and morbidity associated with these procedures. We have extended the use of CT guided stereotaxic surgery to functional conditions by measuring the target position in relation to the third ventricle and the AC-PC line as seen on the unaugmented CT scan. Our experience with 27 procedures in 23 patients (9 movement disorders, 13 pain and 1 insertion of depth electrode) would indicate it is at least as accurate as other techniques. The surgical time is usually shorter and patient tolerance is better.

In vitro photoradiation therapy of the rat 9L gliosarcoma

The authors have investigated various factors involved in the photoradiation treatment of 9L glioma cells. The cells were grown in tissue culture and exposed to light from a laser source that allowed accurate quantitation of the light energy. Cell death was determined following treatment using the trypan blue exclusion test. It was shown that the treatment is very wavelength-dependent following the absorption spectrum of hematoporphyrin derivative (HPD). The absorption peaks in the lower part of the spectrum are more efficient than those of higher wavelengths. Photoradiation therapy is more effective the higher the concentration of HPD. Intensity of light is a very important factor in calculating the total dose of light necessary for this treatment.

Penetration of hematoporphyrin derivative into rat brain and intracerebral 9L glioma tissue

Brain and glioma tissue levels of tritiated hematoporphyrin derivative (3H-HPD) were measured in normal and 9L intracerebral glioma-bearing rats at 24 hours following administration of 3H-HPD 2-20 mg/kg and at 24-120 hours after 3H-HPD 10 mg/kg. Levels of 3H-HPD in blood, liver, spleen and muscle were also measured. Tissue levels of 3H-HPD increased progressively as the dose was increased. In animals given 10 mg/kg, gradual decreases in tissue levels occurred between 24 and 72 hours but thereafter remained stable. The 3H-HPD level in gliomas was consistently 2-3 X greater than in brain tissue, despite changes in dosage and time interval. High levels of activity were measured in normal brain tissue at all dosage levels, and subsequent clearance of the 3H-HPD from brain, glioma, and other tissues was slow; at 120 hours after administration of 10 mg/kg, approximately 50% of the 24 hour level was still present. These results indicate that although a dose- and time-independent preferential uptake of hematoporphyrin derivative occurs in intracerebral gliomas, persistent high levels may be present in the surrounding brain. The disadvantages of using hematoporphyrin derivative rather than its individual components in studies of HPD uptake and photosensitization in the brain are discussed.

Evaluation of diagnostic procedures for detection of mycoplasmal pneumonia of swine

The complement-fixation test (CFT), a latex-agglutination test (LAT), and Mycoplasma hyopneumoniae isolation procedures were compared with gross and microscopic lung evaluations for the routine diagnosis of mycoplasmal pneumonia (MP) of swine. The difficulty and variability of M hyopneumoniae isolation rendered this technique unacceptable. In market-weight swine, the finding of typical gross lesions was correlated with CFT results (P less than 0.005). The MP status of a herd could not be determined by use of these techniques in 4- to 9-week-old pigs. No technique could be used alone to establish a diagnosis. Gross and microscopic examination of all slaughter specimens, CFT, and clinical evaluation of the herd, used in combination, were the most useful means of determining the MP status of the herd.