An Oral-Diffusion-Sink Device for Extended Sampling of Multiple Steroid Hormones from Saliva

Performance of a new oral-diffusion-sink (ODS) device for sampling the steroid hormones cortisol, progesterone, estradiol, and testosterone from human saliva was tested in vitro. The tested device differed from an earlier ODS sampler by using a polymeric composition of beta-cyclodextrin rather than an antiserum to bind analytes diffusing into the device. The capacity of the cyclodextrin-driven device to accumulate the steroid hormones from a simple buffer, human saliva, and saliva fortified with high concentrations of glucocorticosteroids was evaluated. Further, the ability of this device to accurately register the average analyte concentration resulting from treatments simulating physiological episodic secretion events was tested. Each steroid showed a characteristic rate of uptake that was unaffected by saliva or high physiological concentrations of competing steroids, and ODS uptake resulting from temporally varied concentrations of the hormone in the medium accurately reflected the time-integrated average concentration. This ODS provides a potential noninvasive and unobtrusive means of sampling the tissue-available concentrations of multiple steroid hormones, with averaging over physiological secretion events.

Less-Invasive Measurement of Tissue Availability of Hormones and Drugs: Diffusion-Sink Sampling

The use of small diffusion-sink sampling devices allows the relatively noninvasive and unobtrusive collection of a specimen that represents, in a precisely interpretable way, the average freely diffusing concentration of an analyte over a biologically relevant period of time. In an orally worn configuration, these sampling devices reject artifacts arising from blood plasma contamination of saliva and provide a time-averaged sample without requiring the subject to adhere to a frequent-sampling schedule. The practical advantages of noninvasiveness are thus combined with a fairly direct method for measuring what seems, in light of our current understanding, most important to know about the relative abundance of the steroid hormones. Whether this specificity of measurement also has practical benefits has yet to be tested.

Verminous Encephalitis in a Horse Produced by Nematodes in the Family Protostrongylidae

Parasitic granulomatous eosinophilic inflammation was observed in the central nervous system (CNS) of a 6-month-old Arabian colt from New York state. Inflammation was associated with eggs, larvae, and adult nematodes in the cerebellum. Nematodes had histological characteristics of the superfamily Metastrongyloidea. The presence of dorsal-spined larvae in the CNS was further indicative of infection with a nematode in the family Protostrongylidae. Infections were most compatible with Parelaphostrongylus tenuis but specific diagnosis was not possible. This is the first definitive report of a protostrongylid nematode infection in a horse.

Oral cancer screening: knowledge is not enough

OBJECTIVES

The purpose of this cross-sectional study was to investigate whether dental hygienists are transferring their knowledge of oral cancer screening into practice. This study also wanted to gain insight into the barriers that might prevent dental hygienists from performing these screenings.

METHODS

A 27-item survey instrument was constructed to study the oral cancer screening practices of licensed dental hygienists in Nova Scotia. A total of 623 practicing dental hygienists received the survey. The response rate was 34% (n = 212) yielding a maximum margin of error of 5.47 at a 95% confidence level. Descriptive statistics were calculated using IBM SPSS Statistics v21 software (Armonk, NY:IBM Corp). Qualitative thematic analysis was performed on any open-ended responses.

RESULTS

This study revealed that while dental hygienists perceived themselves as being knowledgeable about oral cancer screening, they were not transferring this knowledge to actual practice. Only a small percentage (13%) of respondents were performing a comprehensive extra-oral examination, and 7% were performing a comprehensive intra-oral examination. The respondents identified several barriers that prevented them from completing a comprehensive oral cancer screening.

CONCLUSIONS

Early detection of oral cancer reduces mortality rates so there is a professional responsibility to ensure that comprehensive oral cancer screenings are being performed on patients. Dental hygienists may not have the authority in a dental practice to overcome all of the barriers that are preventing them from performing these screenings. Public awareness about oral cancer screenings could increase the demand for screenings and thereby play a role in changing practice norms.

Naturally Occurring Parelaphostrongylus tenuis–Associated Choriomeningitis in a Guinea Pig With Neurologic Signs

An adult male guinea pig ( Cavia porcellus) with a 1-month history of hind limb paresis, torticollis, and seizures was euthanized and submitted for necropsy. Gross examination was unremarkable, but histologic examination revealed multifocal eosinophilic and lymphoplasmacytic choriomeningitis and cross sections of nematode parasites within the leptomeninges of the midbrain and diencephalon. Morphologic features of the nematode were consistent with a metastrongyle, and the parasite was identified as Parelaphostrongylus tenuis by polymerase chain reaction testing and nucleotide sequencing. Further questioning of the owner revealed that the guinea pig was fed grass from a yard often grazed by white-tailed deer ( Odocoileus virginianus). To the authors’ knowledge, this is the first report of a naturally occurring P. tenuis infection in a guinea pig.

Risk factors associated with Cryptosporidium infection on dairy farms in a New York State watershed

A cross-sectional study was carried out to determine the prevalence of Cryptosporidium parvum-like oocyst shedding on dairy farms in a watershed in New York State and to identify the factors that put animals at risk. A proportional sample of dairy herds in the targeted area was obtained, and animals were selected using a stratified sampling design to ensure representation of the population at risk. Fecal samples were collected per rectum and analyzed for the presence of C. parvum-like oocysts using the quantitative centrifugation concentration flotation technique and a proprietary enzyme-linked immunoassay. Additionally, isolates of Cryptosporidium were examined via bidirectional DNA sequencing. Data on putative risk factors were collected at the time of sampling and analyzed for association using logistic regression. The herd prevalence was 42% and the overall animal prevalence was 3.2%. The prevalence among animals less than 60 d of age was 20%. The likelihood of shedding Cryptosporidium decreased with the age of the animal and varied with the type of barn water source. Both the number of unweaned calves present at the time of the study, and whether the calves were tied vs. not tied increased the risk of infection. There was significant agreement between the flotation and PCR techniques. Sequencing revealed that 50% of the isolates were Cryptosporidium bovis, an isolate thought to be nonzoonotic.

Number of Cryptosporidium parvum oocysts or Giardia spp cysts shed by dairy calves after natural infection

OBJECTIVE

To determine the total number of Cryptosporidium parvum oocysts and Giardia spp cysts shed by dairy calves during the period when they are most at risk after natural infection.

ANIMALS

478 calves naturally infected with C. parvum and 1,016 calves naturally infected with Giardia spp.

PROCEDURE

Oocysts or cysts were enumerated from fecal specimens. Distribution of number of oocysts or cysts versus age was used to determine the best fitting mathematic function. Number of oocysts or cysts per gram of feces for a given duration of shedding was computed by determining the area under the curve. Total number of oocysts or cysts was calculated by taking the product of the resultant and the expected mass of feces.

RESULTS

Intensity of Cparvum oocyst shedding was best described by a second-order polynomial function. Shedding increased from 4 days of age, peaked at day 12, and then decreased. An infected 6-day-old calf would produce 3.89 x 10(10) oocysts until 12 days old. Pattern of shedding of Giardia spp cysts was best described by exponential functions. Intensity of shedding increased from 4 days of age, peaked at day 14, and then decreased. An infected calf would produce 3.8 x 10(7) cysts from day 50 until day 56.

CONCLUSIONS AND CLINICAL RELEVANCE

The large number of oocysts and cysts shed indicates that shedding by dairy cattle poses a risk for susceptible calves and people. Estimates reported here may be useful to aid in designing cost-effective strategies to manage this risk.

Prevalence of enteric zoonotic agents in cats less than 1 year old in central New York State

A prevalence study of several enteric zoonotic bacterial and parasitic infections was conducted in 263 fecal samples from cats that were between 1 and 12 months old, and that were in humane shelters (n = 149) or were presented to primary-care veterinarians (n = 114). Of these samples, 2 (0.8%) were positive for Campylobacter, 2 (0.8%) were positive for Salmonella, and 10 (3.8%) were positive for Cryptosporidium, confirming that these zoonotic agents are relatively rare in cats. Toxocara cati (33.0%) and Giardia (7.3%) were found more commonly. At least 1 zoonotic agent was detected in 105 samples (40.7%). Our results suggest that clinical signs such as diarrhea are not reliable predictors of whether a cat is actively shedding enteric organisms. Therefore, the decision to test a newly adopted cat should be based on the potential risks to the client rather than on the cat's clinical presentation. The high prevalence of T. cati confirms that comprehensive testing or treatment for ascarids is warranted in newly adopted kittens.

Detection of Cryptosporidium oocysts in soil samples by enzyme-linked immunoassay

An ELISA protocol was adapted for detection of Cryptosporidium parvum oocysts in soil samples and the limit of detection of the test was determined. A modified indirect antigen capture ELISA protocol was developed using monoclonal antibodies against the oocyst outer wall. The accuracy of the ELISA was compared to spiked soil samples and measured in terms of sensitivity and specificity of the test. The performance of the ELISA was evaluated in field soil samples and measured using the kappa-statistics. Similarly, the performance of the ELISA was compared to the concentration flotation method, to a modified concentration flotation method and to a commercial ELISA (ProSpecT) in field fecal and soil samples. The limit of detection of the test was selected to be 10,000 oocysts/g. At this limit of detection, the ELISA had a sensitivity of 95% and specificity of 100%. The agreement between the ELISA and the modified flotation-concentration method in detecting Cryptosporidium oocysts in soil samples was 32% (kappa=0.32). The ELISA had the same relative sensitivity (82%) in comparison to both the flotation and ProSpecT in determining Cryptosporidium-infection status of an animal. The kappa-statistics was 0.26 for both tests. The developed ELISA proved to be a valuable diagnostic test for detecting oocysts in soil samples and has a potential application in determining the infection status of animals.

Prevalence of Giardia sp. Cryptosporidium parvum and Cryptosporidium andersoni (syn. C. muris) [correction of Cryptosporidium parvum and Cryptosporidium muris (C. andersoni)] in 109 dairy herds in five counties of southeastern New York

A cross-sectional study was undertaken to determine the prevalence of Giardia sp. (G. duodenalis group), Cryptosporidium parvum and Cryptosporidium andersoni (C. muris) [corrected] in dairy cattle in three different age groups, and to evaluate the association of age and season with prevalence. One hundred and nine dairy farms, from a total of 212 farms, in five counties of southeastern New York volunteered to participate. On these farms, 2943 fecal samples were collected from three defined age groups. The farms were randomly assigned for sampling within the four seasons of the year. Each farm was visited once during the study period from March 1993 to June 1994 to collect fecal samples. Demographic data on the study population was collected at the time of sampling by interviewing the farm owner or manager. At collection, fecal samples were scored as diarrheic or non-diarrheic, and each condition was later related to positive or negative infection with these parasites. Fecal samples were processed using a quantitative centrifugation concentration flotation technique and enumerated using bright field and phase contrast microscopy. In this study, the overall population prevalence for Giardia sp. was 8.9%; C. parvum, 0.9%; and C. muris, 1.1%. When considering animals most at the risk of infection (those younger than 6 months of age) Giardia sp. and C. parvum was found in 20.1 and 2.4% of the animals, respectively. Giardia sp. and C. muris were found in all age groups. There was no significant seasonal pattern of infection for any of these parasites.

Epidemiologic study of Giardia sp. infection in dairy cattle in southeastern New York State

To identify animal and management factors associated with the risk of Giardia sp. infection in dairy cattle in southeastern New York State, an observational analytical epidemiologic study was conducted. A random sample of 2943 animals in 109 dairy herds located in five counties of southeastern New York was selected from the target population. Fecal samples were collected from animals in the study population and examined for the presence of Giardia sp. using a quantitative centrifugation concentration flotation technique. Data on each animal, and on general management, maternity, preweaning, and postweaning practices were collected by personal interview with the farmer or farm manager. The significance of association of these factors, within each management practice group, with the risk of infection was evaluated using the logistic regression analysis. Weighted indices for each of these four groups were developed, and were evaluated together with the age of the animal and season of sampling for their significance of association with the risk of infection using mixed effect logistic regression analysis. Only the maternity management practices, age of the animal, and the season of sampling were significantly associated with the risk of infection with Giardia sp. Summer housing of bred heifers, on pasture or in tie stalls, was associated with increased risk of infection. Calves that were fed fresh colostrum or separated immediately after birth from the dam were at decreased risk of infection. The risk of infection decreased with the age of the animal and varied by the season of sampling. There was no significant extra binomial variation in the risk of infection in this data. If consideration is to be given to reducing the risk of infection with this parasite, management must be a top priority, especially in younger animals.

Risk factors associated with Cryptosporidium parvum infection in dairy cattle in southeastern New York State

An observational analytical epidemiologic study was carried out to identify factors associated with the risk of infection with Cryptosporidium parvum in dairy herds in southeastern New York state. A random sample of 2943 cattle on 109 farms was selected from the target population. Fecal samples were collected from animals in three different age groups and examined for the presence of C. parvum using a quantitative centrifugation concentration flotation method. Data on intrinsic, preweaning, postweaning, maternity, and general management factors were collected and evaluated for their association with the risk of infection with C. parvum. Indices for each of these categories of management were developed from factors significantly associated with the risk of infection with C. parvum. Significant factors were identified using the logistic regression statistical technique. A final analysis, including the indices, age, and season, was performed to identify factors significantly associated with the risk of infection with C. parvum while simultaneously controlling for the effect of other factors. The farm effect was evaluated using a mixed effect model. Preweaning factors found to be significantly associated with a decreased risk of infection were: use of ventilation in calf rearing areas, daily addition of bedding, feeding of milk replacer, daily disposal and cleaning of bedding, and use of antibiotics. Postweaning factors such as moving of the animals after weaning, cleaning of soiled bedding, and use of antibiotics and ionophores as preventive measures were significantly associated with the decreased risk of an infection with C. parvum. Consideration of maternity management factors showed that winter housing of cows individually within 2 months of calving, use of fresh colostrum to feed calves, and having a concrete floor in the calving area were significantly associated with decreased risk of C. parvum infection. The total number of dairy cattle, total number of other species of agricultural animals on the farm, and the distance of the barn water source from the septic system were found to be significantly associated with increased risk of C. parvum infection. In the final analysis, the risk of infection with C. parvum was significantly decreased with an increased value of the maternity management index score. The general management significantly affected the risk of infection with C. parvum where the risk increased with the increase of the value of the index. The risk of infection significantly decreased with increase in the age of the animal.

A simple whole-blood test for detecting antibodies to human immunodeficiency virus

We developed an immunochromatographic whole-blood test (WBT) which detects antibodies to human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) from fingerstick blood. The sensitivity and specificity of the WBT were 99.41% (1,018 confirmed positive patients) and 99.89% (941 uninfected patients), respectively (enzyme immunoassay [EIA] on serum or plasma as a reference). WBT performance was comparable to those of licensed EIAs and Western blotting, using 18 HIV-2 sera, 23 HIV-1 seroconversion panels, and a low-titer performance panel (in lieu of whole blood).

A field test for the detection of antibodies to human immunodeficiency virus types 1 and 2 in serum or plasma

In response to the need for simple and rapid tests for infectious diseases, we have devised a test for antibodies to human immunodeficiency virus type 1 (HIV-1) and HIV-2 which resembles many contemporary strip-style pregnancy tests in format and ease of use. The test was evaluated with 2,928 serum specimens (1,541 reactive and 1,387 nonreactive) collected and tested at a Mexico City hospital clinic and was compared with a laboratory assay (Abbott) performed simultaneously. The sensitivity and specificity of the test using these serum specimens were 99.68 and 99.71%, respectively (before the code of the blinded study was broken). This compares with 100% sensitivity and 97.55% specificity with the laboratory assay (specificity upon reassay after the code was broken, 99.21%). In a survey of HIV-2 specimens, reactive (positive) specimens were detected in 51 of 51 cases. The test was examined with 21 commercially available (HIV-1) seroconversion panels. The performance of the test was comparable to that of a group of Food and Drug Administration-approved (antibody-based) HIV tests.

Resting metabolic rate and diet-induced thermogenesis in restrained and unrestrained eaters

OBJECTIVE

The hypothesis was studied whether restrained eaters had reduced resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) and whether the effect was caused by weight cycling.

METHOD

12 restrained and 12 unrestrained eaters (classified by the Three Factor Eating Questionnaire) were studied with regard to RMR an DIT by direct calorimetry using a ventilated hood system. In a second study 12 weight cycling restrained eaters and 12 weight stable restrained eaters were compared.

RESULTS

Restrained eaters had significantly lower RMR than unrestrained eaters. No difference in DIT was found. Weight cycling and no weight cycling restrained eaters did not differ with regard to RMR and DIT.

DISCUSSION

These data indicate that restrained eating but not weight cycling significantly reduces RMR.

Case report of and description of parasite in Mammomonogamus laryngeus (human syngamosis) infection

About 100 cases of human infections with Mammomonogamus laryngeus (Syngamidae, Syngaminae) have been reported, with virtually all cases originating in the Caribbean Islands and Brazil. This report describes the fifth patient in North America infected with M. laryngeus and the first case documented to originate in Jamaica. The patient complained of a characteristic persistent nonproductive cough and a lump in her throat. M. laryngeus is a nematode in which the male and female are permanently joined in copula, producing a distinctive Y shape. Since there is scant clinical information about this parasite, this report includes a description of the adult worms and eggs, a summary of the epidemiology, and the clinical manifestations in humans. Illustrations are presented to facilitate future identification of this parasite and to expedite treatment.

Physical activity, total energy expenditure, and food intake in grossly obese and normal weight women

The doubly labeled water method was used to measure average daily total energy expenditure (TEE) in 10 healthy normal weight women classified as unrestrained eaters and in 10 grossly obese women. The body mass index was 20.0 +/- 1.3 kg/m2 in the control group and 37.4 +/- 8.1 kg/m2 for the obese group. TEE was measured over a 2-week period. TEE was 2,357 +/- 504 kcal/day for the controls and 3,708 +/- 367 kcal/day for the obese group during a cognitive-behavioral treatment.

An oral-diffusion-sink device for extended sampling of multiple steroid hormones from saliva

Performance of a new oral-diffusion-sink (ODS) device for sampling the steroid hormones cortisol, progesterone, estradiol, and testosterone from human saliva was tested in vitro. The tested device differed from an earlier ODS sampler by using a polymeric composition of beta-cyclodextrin rather than an antiserum to bind analytes diffusing into the device. The capacity of the cyclodextrin-driven device to accumulate the steroid hormones from a simple buffer, human saliva, and saliva fortified with high concentrations of glucocorticosteroids was evaluated. Further, the ability of this device to accurately register the average analyte concentration resulting from treatments simulating physiological episodic secretion events was tested. Each steroid showed a characteristic rate of uptake that was unaffected by saliva or high physiological concentrations of competing steroids, and ODS uptake resulting from temporally varied concentrations of the hormone in the medium accurately reflected the time-integrated average concentration. This ODS provides a potential noninvasive and unobtrusive means of sampling the tissue-available concentrations of multiple steroid hormones, with averaging over physiological secretion events.

Less-invasive measurement of tissue availability of hormones and drugs: diffusion-sink sampling

The use of small diffusion-sink sampling devices allows the relatively noninvasive and unobtrusive collection of a specimen that represents, in a precisely interpretable way, the average freely diffusing concentration of an analyte over a biologically relevant period of time. In an orally worn configuration, these sampling devices reject artifacts arising from blood plasma contamination of saliva and provide a time-averaged sample without requiring the subject to adhere to a frequent-sampling schedule. The practical advantages of noninvasiveness are thus combined with a fairly direct method for measuring what seems, in light of our current understanding, most important to know about the relative abundance of the steroid hormones. Whether this specificity of measurement also has practical benefits has yet to be tested.

Utility of an oral diffusion sink (ODS) device for quantification of saliva corticosteroids in human subjects

Measurement of cortisol by assay of single blood or saliva samples is inherently imprecise due to the episodic secretion of cortisol. In addition, assay of blood usually quantifies total cortisol, rather than separating free hormone, which is proportionately the much smaller fraction. Furthermore, the free fraction may be disproportionately higher in hypercortisolism. Urinary free cortisol is one measure that provides both a time integral and a focus on the free fraction, but it is inconvenient and prone to collection error in unsupervised ambulatory subjects. The Oral Diffusion Sink (ODS) apparatus takes up corticosteroids from saliva according to first-order kinetics and may provide a practical alternative. We assessed the utility of the ODS in a study of seven healthy volunteers admitted to the CRC for three days. Data on day two from 0700-1100 h and 1100-1500 h were compared between the ODS and three other means of assessing cortisol: urinary free cortisol (UFC), blood, and saliva. The subjects all tolerated wearing the ODS device without any complaint. High correlations were observed between ODS values vs. data for UFC, plasma, and saliva determinations. In summary, the ODS device was well tolerated and collected reliable corticosteroid data, and thus provides a new, non-invasive methodology for studies of HPA function in health and disease.

Time-integrated measurement of corticosteroids in saliva by oral diffusion sink technology

Saliva, as a medium for assessing adrenocortical function in humans, has many advantages and a few distinct disadvantages. Interpretation of measurements of saliva cortisol is complicated by the contamination of saliva by steroid-binding proteins from blood plasma, enzyme activity in the salivary gland that converts cortisol to cortisone, and the amplification in saliva of the episodic fluctuations in systemic cortisol concentrations. We describe a new measurement technology that rejects artifacts from contamination of saliva by plasma protein, provides for measurement of both cortisol and cortisone, and integrates episodic fluctuations in concentration over a period of hours. This oral diffusion sink technology may greatly enhance the reliable interpretation of corticosteroid concentrations measured in saliva.

Prevalence of patent Baylisascaris procyonis infection in raccoons (Procyon lotor) in Ithaca, New York

The prevalence of patent Baylisascaris procyonis infection in raccoons was determined by examining fecal samples collected between July 1986 and May 1987 in Ithaca, New York. September, October, and November had the highest prevalence of infection (35-48%). Significant differences (P less than 0.001) were found when months were grouped by season to test the hypothesis that a fecal sample's probability of being positive does not vary from month to month. Fall was the season contributing most to the overall chi-square statistic. Host sex/age class and prevalence of patent infection were investigated. The raccoons were aged as either juveniles or adults. A significantly higher prevalence of patent infection (P less than 0.001) was found in juveniles when compared to adults. No statistically significant difference was found in other comparisons of host sex and age. Contingency analysis tested the independence of sex/age class/season and presence of eggs. The results of the test were significant (P less than 0.001).

Eurytrema procyonis in a raccoon (Procyon lotor) from New York state--a first report

The digenean, Eurytrema procyonis, found in the pancreatic ducts of the raccoon (Procyon lotor), is reported for the first time from a juvenile female raccoon captured in July 1987, in New York State (USA). The presence of greater than 183 trematodes in the pancreatic ducts was an incidental finding at necropsy to an interstitial pneumonia which had caused emaciation, and for which the animal was euthanized. The pancreas, with the exception of the major pancreatic duct, was histologically normal. The duct, containing the parasites, was dilated and contained a diffuse subepithelial inflammatory infiltrate consisting primarily of eosinophils. Epithelial hyperplasia was present in tubulo-alveolar glands, and goblet cells were prominent.

Schistosoma mansoni: mechanism of attrition and routes of migration from lungs to hepatic portal system in the laboratory mouse

The number of schistosomula in the axillary lymph nodes of mice was determined by compressed tissue autoradiography at 13 intervals from 0.5 to 28 days after exposure of abdominal skin to 75Se-labeled cercariae of S. mansoni. Significant accumulations were observed between days 3 and 6 and peaked on day 4 at which time 9.4 +/- 1.1% of the schistosomula present in the whole body were found in the axillary lymph nodes. The total number and distribution of schistosomula in all tissues of mice were likewise determined at 12 intervals from 3 to 24 days following exposure. The frequent appearance of small numbers of schistosomula in trachea and esophagus suggested that normal attrition resulted at least in part from physical expulsion of schistosomula from the body by way of the tracheobronchial tree and gastrointestinal tract. The distribution of schistosomula observed in heart chambers, caudal vena cava, hepatic portal vein, aorta, intestinal wall, thoracic cavity rinses, and diaphragm supported all 3 standing hypotheses regarding route of migration from lungs to hepatic portal system, i.e., that schistosomula migrate via (1) the pulmonary artery, right heart, caudal vena cava, and hepatic veins, (2) the pulmonary vein, left heart, aorta, and cranial mesenteric artery, and (3) the thoracic cavity and diaphragm.

Radiolabeling and autoradiographic tracing of Toxocara canis larvae in male mice

Artificially hatched infective larvae of Toxocara canis were labeled with 75Se in Medium 199 (Gibco) containing 75Se-methionine. Male CD-1 mice were infected with radiolabeled larvae by intragastric intubation or by intraperitoneal injection. At intervals of 3-56 days mice were killed and the organs prepared for compressed organ autoradiography. Radioactivity of parasitic larvae showed an exponential decrease with time, reflecting catabolism of label with a biological half life of 26 days (effective half life of 21 days) making possible experiments lasting several months. Total body larva counts, estimated by total body autoradiography, displayed an overall downward trend, but the rate of reduction was probably not constant because no significant positive or negative trends were noted from day 14 onward in the numbers of larvae. The carcass accumulated the greatest number of larvae followed by the central nervous system, liver, and lung in that order. When the numbers of larvae were considered in relationship to the mass of tissue, there were 4 groupings: central nervous system, liver, lung, carcass, and kidney, and genito-urinary organ, pelt, and intestine. No significant difference between intragastric and intraperitoneal administration was observed in the larval distribution after the larvae had left the initial site of deposition.

Attrition and temporal distribution of Schistosoma mansoni and S. haematobium schistosomula in laboratory mice

The total number and distribution of schistosomula of Schistosoma mansoni and S. haematobium in all tissues and organs of mice from infection to 14-27 days was determined by compressed tissue autoradiography. Attrition of schistosomula, manifested as a decrease in the number of autoradiographic foci, was observed in organs other than the liver. Attrition commenced about 2 days after cercariae entered the skin, and conformed to a single exponential function with a rate constant (+/- standard error) of 7.0 +/- 0.5%/day for S. mansoni and 3.2 +/- 0.7%/day for S. haematobium. The temporal distribution of schistosomula of S. mansoni and S. haematobium differed quantitatively. In the case of S. mansoni, concomitant with a decrease in skin counts, the lung curve rose rapidly to a peak centred on day 6 and thereafter decreased more or less parallel to the total body curve. Significant accumulation in the liver was not observed until day 7, whereupon liver counts rose steadily to a plateau that extended from about day 14 to the end of the experiment and approximated the number of adult worms recovered from the hepatic portal vessels on day 42. A maximum of 26% and mean of 12% of all foci in the body were counted on autoradiograms of tissues other than the skin, lung and liver. The pelt averaged 14% of the body weight yet schistosomula were detected only in the area initially exposed to cercariae. The eviscerated carcass averaged 54% of the body weight yet contained only 0.8%-3.4% of the schistosomula during the period of accumulation in the liver. Between day 6 and day 14, the ratio of schistosomula in the pulmonary circulation to schistosomula in the systemic circulation did not remain constant, as would be the case if schistosomula circulated passively and randomly, but instead displayed a statistically significant decrease from 0.92 and 0.85. For these reasons, it was considered unlikely that schistosomula had circulated randomly and repeatedly through the pulmonary and systemic circulations and entered the hepatic portal system by chance as hypothesized by Miller & Wilson (1980). Instead it was considered more probable that schistosomula migrating from lungs to liver had followed a directed path through intervening vessels (Kruger, Heitman, van Wyk & McCully, 1969) or tissues (Wilks, 1967).(ABSTRACT TRUNCATED AT 400 WORDS)

A direct method for determination of the time integral of corticosterone availability in interstitial fluid of rats

A novel method for direct determination of the time integral of free corticosterone levels in interstitial fluid was used to measure corticosterone availability at rest and during free-operant shock-avoidance (SA) training in male rats. The method employs a subcutaneously implanted device to continuously accumulate the free hormone at a rate proportional to local concentration. The proportional rate of accumulation is maintained by providing mass-action corticosterone binding capacity within the device such that the device establishes a diffusion gradient for free corticosterone. The rate of uptake is limited so as to avoid disturbing equilibrium between free and bound hormone in the environment of the device. Corticosterone accumulation increased to 3 X baseline during SA and was dexamethasone suppressible. These findings demonstrate the utility of a method uniquely combining specific measurement of free hormone with time integration to yield estimates of hormone availability during behavioral performance by an untethered subject. The method is suggested to be applicable to measurement of an extremely wide variety of drugs and hormones, under generally nonconstraining conditions.

Serotonergic changes in specific areas of rat brain associated with activity--stress gastric lesions

To study serotonergic involvement in the development of gastric lesions following activity wheel stress, three groups of rats (gastric lesions, no gastric lesions, and home--cage controls) were killed following exposure to the experimental procedures. The brains were dissected into eight specific areas and subjected to analyses for serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) using high performance liquid chromatography with EC detection. Lower levels of 5-HT were found in the midbrain, cortex, and hippocampus of rats with gastric lesions compared to either the no lesion group, subjected to shorter periods of activity--stress, or the home--cage control group. Levels of 5-HT and 5-HIAA were elevated in the pons/medulla oblongata of both the lesion and the no lesion groups compared to the home--cage controls. Corticosterone levels in blood were also significantly elevated in the lesion group. These data on serotonin changes in the CNS suggest a possible role for this neurotransmitter in stress-induced gastric pathology.

Loss of Purkinje cell-associated benzodiazepine receptors spares a high affinity subpopulation: a study with pcd mutant mice

In order to identify the relative number of benzodiazepine (BZ) receptors in Purkinje and granule cells, the Purkinje cell degeneration (pcd) mutant mouse was used at different ages. In these mice, Purkinje cells have degenerated almost completely by 45-50 days of age. Granule cell loss occurs only later, and is most severe between 180 and 300 days. [3H]Flunitrazepam (FNZ) and [3H]ethyl-carboline-3-carboxylate (beta-CC) were used as ligands. In the 45-50-day-old pcd mice, it was found that there is approximately a 50% decrease in the number of receptors as labeled by [3H]beta-CC or [3H]FNZ, when the binding is expressed as fmol/cerebellum. The binding decreased by approximately 80% in 300-day-old pcd mice (fmol/cerebellum). [3H]FNZ was not displaced by 1 microM RO5-4864, ruling out binding to glial cells. Nonlinear regression analysis of FNZ saturation data provided evidence for two populations of receptors (high and low affinity sites). Only the low-affinity sites were reduced in number at 45 days. [3H]beta-CC saturation data showed, however, only one population of receptors. The total number of receptors (Bmax) was significantly lower for beta-CC than for FNZ in the control mice. It appears that 50% of the total BZ receptors is associated with Purkinje cells. In addition, our data on 300-day-old pcd mutants strongly suggest the existence of granule cell-associated BZ receptors.

Ostertagiosis in captive bison in New York State: report of nine cases

Type II ostertagiosis was found at necropsy in 9 American bison (Bison bison) from 3 farms in New York. Clinical signs included severe diarrhea, emaciation, unthrifty coats, anemia, and weakness. In severely affected animals, the macroscopic abomasal changes consisted of irregular thickening and edema of the mucosa, resulting in a pebbly or morocco-leather appearance. Microscopically, many gastric pits and glands were dilated, lined by hyperplastic epithelium, and contained nematode sections or debris. Parasites recovered included Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus lerouxi, Cooperia oncophora, Haemonchus contortus, Nematodirus helvetianus, Trichuris discolor, Setaria labiato-papillosa, Dictyocaulus viviparus, Hypoderma lineatum, and Sarcocystis sp. Nodules in the small and large intestine were attributed to Oesophagostomum sp. Trichostrongylus lerouxi, Trichuris discolor, and Nematodirus helvetianus are reported from bison for the first time.