Volumetric changes of the upper airway following maxillary and mandibular advancement using cone beam computed tomography.

The objective of this project was to retrospectively evaluate changes in volume of different compartments of the upper airway in response to maxillary, mandibular, and bimaxillary advancement surgeries and to predict the extent of volumetric changes associated with these surgical movements. Pre- and post-surgical cone beam computed tomography scans of 36 patients were evaluated for changes in nasal cavity, nasopharyngeal, oropharyngeal, and hypopharyngeal compartments. The amount of movement for each surgery was measured from skeletal landmarks to reference planes and was correlated with volumetric changes. Maxillary advancement of 4.0±2.2mm increased the oropharyngeal volume significantly (41.40%), and mandibular advancement of 3.8±1.6mm also significantly increased the oropharyngeal volume (21.17%). Bimaxillary advancement of 5.1±1.3mm for the maxilla and 6.4±3.1mm for the mandible significantly increased nasopharyngeal (27.45%), oropharyngeal (66.39%), and hypopharyngeal (52.48%) volumes. Furthermore, for every millimeter anterior movement, oropharyngeal volume increased by 2319.2±771.8mm3. Bimaxillary advancement showed a greater increase than isolated maxillary and mandibular advancement in all pharyngeal compartments. Every millimeter of advancement in the bimaxillary group led to a significant increase in oropharyngeal volume, while every millimeter downward movement showed a significant increase in nasopharyngeal volume.

Cell-mediated cytotoxicity expressed by lymphoid cells from rats with asbestos-induced peritoneal mesothelioma towards rat fetal cell.

Cell-mediated immunity (CMI) directed towards rat fetal cells was evaluated in Fischer F344 young inbred male rats having asbestos-induced peritoneal mesothelioma. The tumors were induced by exposure to Canadian chrysotile B fibers and the CMI delineated by the injury and destruction brought about to 6- to 10-day-old primary fetal cell cultures by the so-called educated peripheral blood lymphoid-cells (PBLC) obtained from the cancer-bearing rats. A significant cytotoxicity was found to be expressed by the PBLCs, suggesting that during the development of mesothelioma, a cellular retrodifferentiation occurs, thereby educating the effectors to recognize a common determinant existing in both the tumor and fetal cells. Educated PBLCs were produced from rats having endodermal tissue cancers (adenocarcinomas of the small bowel, colon and pancreas) and were found to also be cytotoxic to the fetal cultures, yet no injury was apparently inflicted upon cultured mesothelioma target cells by these effectors. These results suggested that the tumor education was specific and that probably a unique and different fetal component was being recognized by the effector cells obtained from the rats with lesions arising either in the mesodermal or endodermal tissue. Further support for this concept was the failure of an antibody, specific to an oncofetal protein existing in endodermal lesions, to apparently recognize any common oncogenic proteins in the mesothelioma. Preliminary studies have also been accomplished which suggests the existence of natural killing immune responses existing to the mesothelioma target cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary palatal development in the chick.

Seventy-nine chick embryos were examined by light microscopy and scanning electron microscopy to determine the mechanism of primary palatal development. Fusion between two discrete processes, the medial nasal and maxillary prominences, was found to be necessary for formation of a complete primary palate. This was one component of a three-stage process that included: (1) invagination of the nasal pit prior to the appearance of the facial prominences; (2) fusion between the medial nasal and maxillary processes caudal to the nasal groove; (3) rupture of the bucconasal membrane. The lateral nasal and maxillary prominences were found to be part of the same tissue mass. Mergence was proposed as a mechanism for the obliteration of the groove between these two localized prominences. These results were compared with those obtained by other authors for primary palate formation in rodents and man.

The combined effects of asbestos ingestion and localized X-irradiation of the colon in rats.

We hypothesized that the normal bowel may afford some protection to tissue penetration of ingested asbestos, due to the mucus produced by goblet cells which normally coats the gut surface. To study this, we exposed localized segments of the colons of laboratory rats to X-irradiation. These animals were then divided into 3 groups which were fed either a diet containing 10% chrysotile asbestos, a diet containing 10% non-nutritive cellulose fiber, or a standard laboratory diet. Autopsies and histopathology were performed on all animals that died spontaneously and those that were killed at 350 days. Various types of inflammatory and degenerative lesions were commonly seen, but there was little difference in frequency between the diet groups. Five adenocarcinomas and two sarcomas were seen in the fiber groups (three tumors in the asbestos group and four tumors in the cellulose group) but no tumors were seen in animals on the standard diet. There was not a significant difference in tumor rates between the asbestos and cellulose groups, nor was there a significant difference between the combined fiber groups and the standard diet group. It was concluded that the x-ray treatment resulted in localized damage to the colonic mucosa and, therefore, theoretically disrupted the normal mucus coating allowing the potential for increased tissue penetration by the asbestos. Ingested asbestos did not increase the risk for tumor development and, therefore, does not seem to be co-carcinogenic or a tumor promoter in combination with disruption of mucus coating and localized X-irradiation.

Evaluation of rotavirus infection and diarrhea in Iowa commercial pigs based on an epidemiologic study of a population represented by diagnostic laboratory cases.

Group A, B, and C rotaviruses were identified in 9% (96/1,048) of pig fecal specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory during 1987 and 1988. Six of the rotaviruses were group B, 5 were group C, and the remaining 89% were group A. Of the rotavirus cases with more than 1 serotype, 5 were multiple group A serotypes, 1 involved a group A and B serotype, and 1 included 2 group C serotypes. A retrospective epidemiologic evaluation of pig diarrhea in herds of origin was done using data obtained from the accession records of the rotavirus and 88 matched nonrotavirus pig diarrhea control cases. Herds from which rotavirus cases were derived experienced lower morbidity, mortality, and case fatality rates than matched control herds. The incidence of diarrhea decreased rapidly among all pigs from birth to 3 weeks of age. The peak incidence for piglet diarrhea occurred in February, and a moderate rise occurred in August-September. Definitive evidence for transmissible gastroenteritis virus was found in 12% of nonrotavirus cases but none of the rotavirus cases in which it was sought. Other pathogenic microorganisms were identified less frequently and inconsistently.

Chronic selenosis in horses fed locally produced alfalfa hay.

Chronic selenosis (alkali disease) was diagnosed in horses of western Iowa, a region associated with marginal to adequate soil selenium. Two locally produced alfalfa hays (Medicago sativa L) were identified as the primary source. Difficulty in selecting diagnostic specimens to evaluate potential chronic selenosis cases is complicated by the wide range of tissue concentrations reported in previous cases, conflicting correlation of sample selenium concentrations in the literature, and different recommendations on specimen selection and diagnostic value. These problems arise form the similarity in clinical signs for mild and severe chronic selenosis cases, and inability to establish the disease time course. Therefore, collection of multiple samples to confirm high selenium concentration in various tissues and identify selenium sources is recommended. Value of samples believed to reflect historical exposure vs current status may be questionable. Interpretation of results by practitioners and diagnosticians should consider selenium exposure level and duration, antagonistic or ameliorating factors, and postexposure excretion.

Persistence of pseudorabies virus in infected swine.

The persistence of pseudorabies virus (PRV) in pigs clinically recovered from the disease was detected by culture of tissue fragments. Weanling pigs were infected by intranasal instillation of 200,000 plaque-forming units of a strain of PRV isolated from sick pigs in Iowa, and virus was recovered from them 6 weeks to 13 months later. Tonsil, trigeminal ganglia, or pooled trigeminal ganglia and olfactory and optic nerve tissue were most consistently the source of virus. The tissue-fragment culture technique was compared with a co-culture technique for detection of virus in tissue specimens from the recovered pigs. Use of these procedures provided the means to detect PRV in pigs for periods longer than previously recognized.

Growth and development in patients with untreated clefts.

Motivated by the observation that individuals with clefts of the lip and palate exhibit different facial growth than those individuals without facial clefts, many studies have assessed dentofacial morphology in order to understand these differing growth patterns. This review addresses current understanding of facial growth in patients with untreated clefts, drawing broad conclusions about the state of the art, and presents a challenge for cleft care in the future.

Illinois Association of Craniofacial Teams: a new state organization.

The Illinois Association of Craniofacial Teams (IACT) is a not-for-profit organization whose members are the 14 teams that treat patients with craniofacial anomalies in the state of Illinois and adjoining areas. The teams represent more than 200 multidisciplinary health professionals. The group was formed in 1983 to foster cooperation and communication between the teams and to encourage public awareness. In addition to providing educational programs, the organization has focused its attention on standards of care, cost analysis of services, third party reimbursement, and incidence reporting of cleft lip and palate. This report reviews the formation, structure, and accomplishments of IACT so that it may serve as a model or guide for other groups who share its goals.

Characteristics of new patients at Illinois cleft palate teams.

The Illinois Association of Craniofacial Teams (IACT) surveyed all new patient visits to member teams in an effort to assess the needs of patients in Illinois. The survey determined the number of patients, their age at initial visit, the location and status of their defect, and their history of team visits. Four hundred eighty new patient visits were recorded. The number of patients was substantially lower than expected, and the large majority of older children seeing a team for the first time had repaired defects. It is concluded that the main opportunity for improving the quality of care for patients with clefts in Illinois may be in increasing the use of cleft palate teams.

Factors influencing the stability of the sagittal split osteotomy for mandibular advancement.

Relapse continues to be a potential problem with use of the sagittal split osteotomy to advance the mandible. In an effort to isolate predictive factors, the records of 235 patients were analyzed to determine the pretreatment facial morphology, the amount of advancement, the amount of relapse, and the duration of relapse. No relationship was found between any of the measures of facial morphology and relapse. However, the amount of advancement, the amount of relapse, and the duration of relapse all were found to be strongly related. It was found that all patients shared a similar facial morphology, and thus no influence of facial form on relapse would be expected from this group. The relationships between advancement and relapse could be attributed to neuromuscular adaptation, which would be more prolonged and more extensive in instances of greater advancement, and thus give rise to relapse of greater extent and duration. It is therefore suggested that mandibular advancements of greater than 10 mm be fixed more rigidly and for a greater length of time than those of lesser magnitude.

Rabies in Oyo State, Nigeria; 1971-1982.

Epidemiologic data gathered from recorded sources in Oyo State, Nigeria, indicates that people are at 2.1 times greater risk there than in Africa generally and 56 times greater than in the United States of America of dying from rabies. Women older than 30 years of age comprised 45% (5/12) of the analyzable rabies cases from 1971 to 1979. Two of these 12 cases were contracted from cat bites and both of these cases were women. The reason for the high rate of rabies in Women (7/12), especially older women, is not known although this may relate to their socio-economic role in this part of Nigeria. Nor is it understood why women are more likely to be bitten by rabid cats. Eighty-seven percent of rabid animals were dogs. Males were at greater wisk of being bitten by an animal than were females at a ratio of 1.8 to 1, but 57% of male and 49% of female bite victims were 14 years of age or lress. Women 35-39 years old were bitten more frequently than would be expected from the dminishing rate displayed with increasing age, and this may explain, at least partially, their involvement in fatal rabies. There were an average of 45 to 50 cases of animal bites reported in Oyo State each month from January 1978 through December 1981, and a drastic rise was seen in January through April of 1980. There was not a parallel increase in human rabies during this 4 month period, however. A wildlife reservoir for rabies was not evident from the Oyo State data and it must be presumed that dogs are the maintenance reservoir for the virus. Questionnaire surveys were not useful during this study, but personal interview and trace-back efforts to gather information were valuable. These latter efforts suggest that rabies is more prevalent than existing records indicate, probably by a factor ranging from 2 to 6 or more. Rabies control in Oyo State will require recording and systematic reporting of human and animal cases to develop meningful programs. These all in turn revolve around the societal recognition and determination to cope with the problem.

Regurgitation and choke in rats.

Male and female F344 rats choked on fecal pellets and regurgitant during the course of two long-term experiments. Each study involved feeding standard and high bulk diets containing 10% wood cellulose or 10% chrysotile asbestos fiber. Choke deaths occurred at all stages of the experiments. A total of 36 of 774 (4.6%) rats in the two studies died of choke. Females died of choke more frequently (26/382 or 6.8%) than did males (10/392 or 2.6%). Rats on high bulk diets were affected more frequently (33/571 or 5.8%), especially those on 10% asbestos diet (26/311 or 8.4%, than rats consuming standard diet (3/190 or 1.6%). The reason for the difference between females and males was not determined. Although choke may be related to some characteristics of high nonnutritive bulk feed fed in pellet form, the higher risk for females even on standard diet (3/95 or 3.2%) than for males (0/95) indicated that more than one factor operated in the etiology of these events.

Allergy and pulmonary impairment in Iowa veterinarians.

If small animal practice exposure, including the laboratory animal situations encountered in academic and other research pursuits, is more detrimental to veterinarians than large animal practice exposure for induction of allergic respiratory disease, then preventive measures such as increased ventilation, use of high efficiency particulate filters, and wearing of masks should be encouraged to reduce allergen exposures. Migration from large animal practice, likewise, should be discouraged. Failure to migrate to low occupational allergy risk situations early enough in a veterinary career can have severe and even fatal results. If the observed respiratory disease in veterinarians is in fact due to exposure, then unfortunately, it may in some cases be progressive and not just chronic. Data which could provide criteria for predicting occupational allergy and possible related respiratory disease outcome is scant at this time and career counselling is difficult. If the veterinary occupational animal allergy data should be proven correct such results can be used to help others.

Condylar position following mandibular advancement: its relationship to relapse.

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times postoperatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwise rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.

The effects of long-term ingestion of asbestos on the colon of F344 rats.

Weanling F344 rats, which were fed a diet containing 10% chrysotile (B), were studied over their life-time to determine the effects of ingested asbestos on the colon. Control groups consisted of rats fed a diet containing a 10% nonnutritive cellulose or a standard laboratory rat diet. The pathological findings in the colons of 501 rats (189 on asbestos diet, 197 on fiber control diet, and 115 on standard control diet), are reported here. Epithelial tumors of the colon (eight adenocarcinomas and one adenoma) were found in nine of the rats on study. Four of the tumors were in asbestos-fed rats, two tumors were found in the non-nutritive cellulose controls, and three tumors were found in the standard laboratory rat diet controls. The probability (based on actuarial analysis) of developing adenoma or adenocarcinomas during the 32 months of the study were 7.4% for the asbestos-fed group, 3.5% for the fiber control diet and 4.0% on the standard control diet. In addition, one malignant mesothelioma of the type induced by intraperitoneally administered asbestos was found in the asbestos-fed group. Non-neoplastic lesions of the colon were also evaluated. The cumulative risk for development of any colon-associated lesion (non-neoplastic plus neoplastic lesions) was greatest for asbestos-fed rats (17.9%), compared to 13.6% for those fed the fiber control diet and 8.2% for those fed the standard control diet. The colon tissue levels of adenosine, 3'-5'-cyclic monophosphate (cAMP) were significantly lower in the animals fed asbestos compared to the control diets. Chrysotile fibers were seen by electronmicroscopy (e.m.) in six of ten ashed colon specimens of rats fed the asbestos diet. Although the differences in numbers of tumors between the animals fed asbestos and the controls were not statistically significant at the 5% level, we felt that the combination of observations including 1) evidence of increased probability of asbestos-fed animals to develop colon lesions in general; 2) evidence of a special type of mesothelioma in rats fed asbestos; 3) evidence for a cell regulator defect (lowered cAMP levels) in colon tissues of animals fed asbestos; and 4) evidence for asbestos fiber penetration of the colonic mucosa (e.m. studies) suggest that ingested asbestos is not inert in the colon.