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Biomedical subjects

G M Shannon

Publications and source records attributed to G M Shannon.

At least 19 recordsLinked to original sources
PubMed1983

Effect of Fusarium roseum (Gibberella zea) on pregnancy and the estrous cycle in gilts fed molded corn on days 7-17 post-estrus.

A laboratory produced corn culture of Fusarium roseum (Gibberella zea) was fed as 10% of the total diet to bred and non-bred gilts on days 7-17 postestrus. The corn culture contained both zearalenone and deoxynivalenol by analysis, and caused considerable feed refusal. Although 6 of 10 bred gilts fed the corn culture appeared to be pregnant by ultrasound testing between days 40-50 post-breeding, none of them farrowed. Progesterone analyses indicated that none of the 10 gilts cycled normally during the 20 week observation period. Three maintained high serum progesterone (greater than 10 ng/ml) during the entire period. Progesterone analyses were similar in 5 non-bred gilts fed the corn culture in that none of them cycled normally in 20 weeks. The retention or loss of corpora lutea could not be attributed to levels of luteinizing hormone, as no relationship was found between concentrations of progesterone and luteinizing hormone. This experiment indicates that limited dietary exposure of female swine to Fusarium roseum infected corn can result in embryonic loss and disruption of normal reproductive cycling for an extended length of time.

Animal Feed↗
PubMed1983

Extraction and thin layer chromatography of aflatoxin B1 in mixed feeds.

A method was developed for the determination of aflatoxin B1 in commercially prepared feeds. The method incorporates methylene chloride and citric acid solution extraction, cleanup on a small silica gel column, and thin layer chromatography for quantitation. Commercial turkey starter, catfish chow, medicated pig starter, broiler finisher, rabbit chow, horse feed, rat chow, and dog chow were investigated. The feeds were spiked with naturally contaminated corn at 4 different levels of aflatoxin B1 (16-130 microgram/kg). Three assays were run on each of the 32 combinations of feed and levels of aflatoxin. Mean recoveries were 85.9-92.8% at levels of 16.5, 32.9, 65.8, and 131.6 micrograms/kg. The relative standard deviation per assay was 18.6%. This method is more rapid and less involved than most previously published methods for mixed feeds.

Aflatoxin B1↗
PubMed1983

Conjunctivodacryocystorhinostomy with mucous membrane graft.

Eleven patients with obstructed lacrimal canaliculi underwent conjunctivodacryocystorhinostomy modified by lining the fistula with buccal mucosa at the time of surgery. Four patients had the tube removed after six months. All four have parent mucous membrane lined fistulas with follow-up ranging from ten to 13 months. One patient removed his tube on the second post-operative day. His fistula closed immediately. For comparison, the remaining six patients retain their tubes. They are free from epiphora but suffer from some of the complications of the tube itself, namely tube extrusion, tube migration, and chronic conjunctival irritation and discharge. The surgical technique is described, histopathologic material is presented, and the initial results are discussed.

Adolescent↗
PubMed1983

Gas chromatographic determination of deoxynivalenol in wheat.

Modifications to a published method are described for the determination of deoxynivalenol (DON) in wheat by gas chromatography with electron capture quantitation of the heptafluorobutyrate derivative. In the modified method, DON is extracted by shaking the sample with methanol-water on a wrist-action shaker, followed by filtration through rapid flow paper. One concentration step is eliminated, and a hexane wash is incorporated to remove toluene from the silica gel column. Recoveries of DON from wheat samples spiked at 0.1, 0.5, and 1.0 ppm ranged from 77.3 to 86.3% and averaged 81.5%.

Chromatography, Gas↗
PubMed1982

Complications of orbital roof fractures.

A spectrum of complications of orbital roof fractures is discussed. The authors have had cooperation with the neurosurgical service in treating nine cases. Careful ocular and neurologic examination of the patient is emphasized in an attempt to avoid ocular complications, orbital deformities, ocular muscular imbalance, enophthalmos, blepharoptosis, and intracranial complications. With intracranial involvement, a combined neurosurgical and ophthalmologic approach is indicated. A superior orbitomy is indicated if there is a simple fracture of the orbital roof without involvement of the inner table of the skull.

Blepharoptosis↗
PubMed1982

Effect of Fusarium roseum corn culture containing zearalenone on early pregnancy in swine.

A corn culture of Fusarium roseum was added to a standard corn-soybean swine gestation ration. Low, middle, and high dosage mixed feeds contained 7, 38, and 64 mg of zearalenone/kg of feed (7, 38, and 64 ppm) and 0.5, 2.5, and 4.5 mg of deoxynivalenol/kg, respectively. Control feed was the standard ration without added F roseum corn culture. Mature gilts were bred by natural service and fed control or F roseum molded feed from 3 to 34 days after breeding. The main effect of the molded feed was an inhibition of fetal development, with decreased numbers of fetuses present in treated animals at slaughter (38 to 43 days after breeding). Normal litters were present in 7 of 8 control animals, in 2 of 4 gilts given the low-dosage feed, in 1 of 4 gilts given the medium dosage, and in 0 of 4 given the high-dosage feed. Corpora lutea were maintained in all treated animals, as evidenced by serum progesterone concentrations. Serum estradiol concentrations were decreased in gilts in the middle- and high-dosage groups. The genital system of the gilts fed low- and middle-dosage feeds had a gross and microscopic appearance similar to that of the pregnant controls and reflected prolonged progesterone stimulation. Morphologic changes in the genital system of the high-dosage group were intermediate between changes induced by progesterone and those induced by estrogen. Clinical signs of hyperestrogenism and partial feed refusal were noticed in only some of the high-dosage group animals.

Animals↗
PubMed1982

Dacryocystorhinostomy: a review of 119 cases.

One hundred nineteen dacryocystorhinostomies were reviewed and were found to be most commonly performed on females in their seventh decade, with silent epiphora being the most common presenting symptom. Trauma was the single most frequent cause of surgery in males and required complex reconstruction in most cases. Three of the seven dacryocystorhinostomy failures occurred in these traumatic dacryostenosis cases. An unusually high percentage of dacryocystorhinostomy surgery was performed on women who had had previous hysterectomies or serious gynecologic pathology.

Adolescent↗
PubMed1981

Minicolumn detection methods for aflatoxin in raw peanuts: collaborative study.

The Holaday-Velasco method and a modified Holaday method have been compared. The former method combines the speed and simplicity of the Holaday extraction and cleanup with the sensitivity of the minicolumn originally described by Velasco. The combination method has been approved by the AOAC and the AACC for determining aflatoxin in corn. The Holaday method was modified by substituting toluene for benzene in the solvent partition, and methylene chloride for chloroform in the minicolumn development to eliminate use of hazardous solvents. The neutral alumina in the Holaday minicolumn was changed from activity V to activity III to provide a more stable column. At aflatoxin levels in raw peanuts of 13-20 ng/g, the presence of aflatoxin was missed by the modified Holaday method in 4 analyses (3 laboratories) of 42 reported. There were no misses in this contamination range by the Holaday-Velasco method. There were no misses by either method with samples containing greater than 20 ng total aflatoxins/g. Analysis of uncontaminated raw peanuts by the modified Holaday method resulted in 2 false positives of 14 reports; the Holaday-Velasco method produced no false positive reports from 15 analyses of uncontaminated peanuts. The Holaday-Velasco method was adopted official first action for peanuts.

Aflatoxins↗
PubMed1980

Orbital roof fractures: neurologic and neurosurgical considerations.

A wide spectrum of orbital roof fractures is presented through four clinical cases. Neurologic examination is emphasized and reviewed in order to detect the orbital roof fractures that may involve intracranial damage. A combined neurosurgical and ophthalmologic approach is indicated in basilar skull fractures with involvement of the inner table. Without intracranial damage or evidence of a dural tear, a superior orbitotomy is indicated to reduce the fracture and release the incarcerated orbital contents to improve ocular motility.

Adolescent↗
PubMed1980

Laboratory screening for zearalenone formation in corn hybrids and inbreds.

Grains from 14 corn inbreds and 4 single cross hybrids were inoculated with 3 isolates of Gibberella zeae to determine their inhibition of zearalenone production. The corn hybrids: Pa762 x A632 (50 mg/kg zearalenone production), A619 x A632 (17 mg/kg zearalenone production), H95 x Mo17 (132 mg/kg zearalenone production), and B73 x MO17 (33 mg/kg zearalenone production) appear to have less resistance than the inbreds to toxin formation. Inbred H95 (64 mg/kg zearalenone production) supported the highest toxin production of all inbreds. The remaining 13 inbreds did not exceed 15 mg/kg zearalenone production. The inbreds A632 (4 mg/kg zearalenone production) and Pa762 (2 mg/kg zearalenone production) demonstrated some resistance; the resulting cross, hybrid Pa762 x A632 (50 mg/kg zearalenone production), does have greater resistance than hybrid H95 x Mo17 (132 mg/kg zearalenone production). Analysis of variance indicated highly significant variation between corn varieties and fungal isolates. The coefficient of variation for 29 fermentations run in duplicate on inoculated control corn to produce zearalenone (212 mg/kg) was 37%, which would include variation in both the fermentation and analysis. Isolate and variety interaction is not significant.

Fermentation↗
PubMed1980

The "corncrib" repair of senile entropion.

A new method of senile entropion repair has been described. The method corrects the entropion by affecting those conditions which create an entropion: enophthalmos, lid laxity, preseptal orbicularis movement, and retractor weakness. A 3.4% recurrence rate in 58 lids followed an average 17 months was found. This procedure is simple and applicable to all senile entropion patients.

Aged↗
PubMed1980

Results of dacryocystorhinostomy: analysis of the reoperations.

Of 291 dacryocystorhinostomies, 18 (6 percent) were considerd anatomical failures. At reoperation, 78 percent were found to have canalicular obstructions with a predominance of common canaliculus. A closed osteotomy was found in four (22 percent). Most of the failures had trauma as the initiating cause of nasolacrimal obstruction. It must be emphasized that our failures were demonstrated by anatomical observation of obstruction at reoperation. We recognize that postoperative tearing is a subjective variable and understand that some failures are asymptomatic.

Adolescent↗
PubMed1980

Subcutaneous-based triangular skin flaps.

Subcutaneous-based triangular skin flaps that have no skin attachments are discussed as a useful method for closing round defects in the medial and lateral canthal regions when adjacent skin is inadequate.

Basal Cell Carcinoma↗
PubMed1979

Minicolumn detection methods for aflatoxin in yellow corn: collaborative study.

The CPC modified method, the Holaday modified method, and the combination of the 2 procedures have been compared. The CPC modified method involves more cleanup steps but has a more sensitive column. The Holaday modified procedure has fewer cleanup steps, but the column is more difficult to interpret. The combination CPC-Holaday, which has proven to be the most satisfactory, combines the speed and simplicity of the Holaday extraction and the sensitivity of the Velasco minicolumn used in the CPC method. Levels of 10 ng/g were detected by 89% of the collaborating laboratories using the combination, Holaday-Velasco, method. The combination method has been adopted as official first action.

Aflatoxins↗
PubMed1978

The effectiveness of the pigtail probe method of repairing canalicular lacerations.

The pigtail probe method of repairing canalicular lacerations is a widely used technique, however its long-range effectiveness has never been documented. By evaluating statistical data on 51 canalicular lacerations, and then examining 30 patients who had been repaired by the pigtail probe we were able to conclude that: a left inferior canalicular laceration, in a young male, following assault is the most common presentation; that this method objectively yields a 36.6% patency rate with a 10% incidence of iatrogenic damage to the uninvolved side; that 73.3% of the failures remained asymptomatic; secondary to keratitis sicca, a functioning conjunctival canalicular fistula, or the patent remaining canaliculus; and that the inferior canaliculus appears to be symptomatically more important than the superior canaliculus. It is suggested that all canalicular lacerations be repaired, but that the pigtail probe method be abandoned.

Adolescent↗
PubMed1977

A new simple method for canalicular intubation.

A series of ten patients had canalicular intubation with Teflon and Silastic tubing. Our experience has shown that Silastic tubing appears to be more pliable, has good capillary action, and causes less irritation within the canalicular system than polyethylene or Teflon tubing. Five patients had very good results, three patients were improved, and there were two failures. We believe that this technique is useful in selected cases where there is an obstructed canaliculus near its junction with the sac. There should be only minimal scarring in the medial canthal area for the greatest chance of success with this method.

Dacryocystorhinostomy↗