Calculation of body surface area of corn snakes (Pantherophis guttatus) utilizing computed tomography

OBJECTIVE

To determine the K-constant for body surface area calculation from body weight in corn snakes (Pantherophis guttatus) through the use of computed tomography (CT) measurements.

ANIMALS

12 adult corn snakes held by North Carolina State University for research purposes underwent CT between November 2022 and January 2023.

METHODS

Each snake had a CT scan, physical examination, and body weight measurement. CT images were uploaded into software able to perform 3-D reconstruction and measure body surface area. The species-specific K-constant was determined using nonlinear regression analysis between body surface area and (body weight in grams)2/3.

RESULTS

The mean body weight of the 12 adult corn snakes was 228 g, with a mean body surface area of 505.1 cm2. The calculated K-constant was 13.6 (P < .001). The resulting formula for body surface area in corn snakes is BSA in cm2 = 13.6 X (body weight in grams)2/3.

CLINICAL RELEVANCE

The body surface area formula developed for corn snakes will allow for improved dosing accuracy for medications with low therapeutic safety margins. Additional pharmacokinetic and pharmacodynamic studies are necessary to determine the safety and efficacy of individual medications.

Use of computed tomography to determine a species-specific formula for body surface area in bearded dragons (Pogona vitticeps)

OBJECTIVE

To use CT-derived measurements to calculate a shape constant (K constant) and create a formula to calculate body surface area (BSA) on the basis of body weight in bearded dragons (Pogona vitticeps).

ANIMALS

12 adult client-owned bearded dragons that underwent CT between December 4, 2019, and April 2, 2020.

PROCEDURES

Each bearded dragon in this prospective cohort study underwent physical examination, body weight measurement, and CT. A 3-D surface model was then reconstructed from CT data with available software and used for BSA calculations. Animals were considered collectively and grouped by sex and age. Nonlinear regression analysis of BSA versus body weight was performed, and a species-specific formula was derived for calculating BSA in bearded dragons.

RESULTS

Mean age, body weight, and CT-derived BSA were 2.1 years, 356 g, and 580 cm². The calculated K constant was 11.6 (R² = 0.994; SE = 0.275) for the 12 bearded dragons, and the CT-derived BSA formula was as follows: BSA in cm² = 11.6 × (body weight in g)^2/3. The K constant differed substantially for bearded dragons grouped by age (12.1 for younger [between 1 and ≤ 2 years of age; n = 8] vs 10.9 for older [> 2 years of age; 4] animals) but did not differ on the basis of sex.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that because the K constant for bearded dragons in the present study was larger than the preexisting K constant of 10 used for reptiles or the various K constants established for some companion mammals, doses of chemotherapeutic drugs needed to treat affected bearded dragons may be higher than previously thought.

Body surface area measurements in male Hartley guinea pigs using a computed tomography scanner

The body surface area (BSA) of animals is generally estimated by multiplying the k value (constant) by the measured body weight (BW) raised to the power of 2/3 (Meeh's formula). Computed tomography (CT) scanners generate detailed 3-dimensional (3D) images of objects, and image analysis does not depend on operator skill. Therefore, the analysis of CT images provides accurate and reproducible BSA measurements. In this study, we measured the BSA of 25 male Hartley guinea pigs from 3 to 36 weeks of age (working BW range: 0.233 to 1.160 kg) using a CT scanner and 3D analysis software. We concluded that the k value for male Hartley guinea pigs was 8.37, based on the mean k value of the 25 animals.

Exogenous creatinine clearence indexed to body surface area allows estimation of GFR and across species comparison

The assessment of renal function in birds is difficult because sensitive biomarkers are lacking. Previous studies have demonstrated the feasibility of measuring the exogenous creatinine clearance in pigeons, indicating the potential use of this technique for the assessment of renal function in birds. The aim of the study was to index the exogenous creatinine elimination rate by body surface area, enabling comparison between different species. Exploratory data on common buzzards (Buteo buteo), Eurasian eagle-owls (Bubo bubo), domestic goose (Anser anser domesticus) and racing pigeons (Columba livia) were collected and indexed by body surface area. A sterile creatinine solution was administered at a dose D_M = 50 mg kg^-1 i.m. into the deep pectoral muscle of 52 clinically healthy birds of the four species with different body masses. The time course of the plasma creatinine concentration was measured and analyzed by a parametric pharmacokinetic Bateman model, followed by indexing the exogenous creatinine clearance (ECC) by body surface area. The exploratory ECC values for birds with a mean body mass ranging from 0.42 kg (pigeon) to 8.2 kg (goose) were between 0.4261 mL min^-1 dm^-2 (CI 0.3882-0.4672) and 0.8717 mL min^-1 dm^-2 (CI 0.8091-0.9362). ECC indexed by body surface area turned out to be independent from body mass. Resulting exploratory data covering species with different body masses are comparable with published data from very complex studies of avian renal function.

A pragmatic approach to assess the exposure of the honey bee (Apis mellifera) when subjected to pesticide spray

Plant protection spray treatments may expose non-target organisms to pesticides. In the pesticide registration procedure, the honey bee represents one of the non-target model species for which the risk posed by pesticides must be assessed on the basis of the hazard quotient (HQ). The HQ is defined as the ratio between environmental exposure and toxicity. For the honey bee, the HQ calculation is not consistent because it corresponds to the ratio between the pesticide field rate (in mass of pesticide/ha) and LD50 (in mass of pesticide/bee). Thus, in contrast to all other species, the HQ can only be interpreted empirically because it corresponds to a number of bees/ha. This type of HQ calculation is due to the difficulty in transforming pesticide field rates into doses to which bees are exposed. In this study, we used a pragmatic approach to determine the apparent exposure surface area of honey bees submitted to pesticide treatments by spraying with a Potter-type tower. The doses received by the bees were quantified by very efficient chemical analyses, which enabled us to determine an apparent surface area of 1.05 cm(2)/bee. The apparent surface area was used to calculate the exposure levels of bees submitted to pesticide sprays and then to revisit the HQ ratios with a calculation mode similar to that used for all other living species. X-tomography was used to assess the physical surface area of a bee, which was 3.27 cm(2)/bee, and showed that the apparent exposure surface was not overestimated. The control experiments showed that the toxicity induced by doses calculated with the exposure surface area was similar to that induced by treatments according to the European testing procedure. This new approach to measure risk is more accurate and could become a tool to aid the decision-making process in the risk assessment of pesticides.

[Study on acupoint-like and meridian-like structure of the body surface in Cryprinus carpiods]

OBJECTIVE

To probe into the relationship between receptors on the body surface of Cryprinus carpiods and meridians and acupoints of Chinese medicine.

METHODS

Six Cryprinus carpiods [body length: (4.0 +/- 0.4) cm] purchased from the market were put into a glass container filling with 30 micromol/L DiA [4-(4-Diethylaminostyryl)-N-Methylpyridinium Iodide] water solution for 2 hours and then anaesthetized (with 2% aether) for observation under fluorescent microscope. Another 6 Cryprinus carpiods [body length: (8.1 +/- 0.6) cm] were put into a pool with 30 micromol/L DiA water solution for 7 days and then anaesthetized for microscopic observation.

RESULTS

1) The DiA-labeled spots appeared on Cryprinus body surface regularly distributing in discontinuous lines, some of them gathered together to form clusters. The labeled spots around the eyes distributed in radial style and in linear arrangement along the margin of the gill cover. On the body trunk, the labeled clusters distributed in linear arrangement along the longitudinal axis of the body and formed 14 lines approximately. 2) In Cryprinus carpiods fed in water with DiA for 7 days, the labeled receptors clearly showed some neuronfibrae.

CONCLUSION

The areatus distribution and linear arrangement of receptors on the body surface in Cryprinus carpiods are similar to those of acupoints and meridians described in the human body in Chinese medicine.

A method for determining the extent of thermal burns in elephants

A practical method was developed to assess the extent of burns suffered by elephants caught in bush fires. In developing this method, the surface areas of the different body parts of juvenile, subadult and adult elephants were first determined using standard equations, and then expressed as a percentage of the total body surface area. When viewed from a distance, the burnt proportion of all body segments is estimated, converted to percentages of total body surface area, and then summed to determine the extent of burns suffered.

Consequences of yellow band disease (YBD) on Montastraea annularis (species complex) populations on remote reefs off Mona Island, Puerto Rico

The rate and extent of mortality from yellow band disease (YBD) to Montastraea annularis (species complex) on reefs off Mona Island, Puerto Rico, was evaluated over 8 yr. Isolated YBD infections were first observed in 1996. Prevalence of YBD increased dramatically in 1999, with a maximum of 52 % of all M. annularis colonies infected in 1 shallow site. YBD continued to spread among adjacent, previously uninfected corals over the next 4 yr, and disease prevalence progressively increased in deeper sites. Linear rates of disease advance and tissue mortality have been slow (5 to 15 cm yr(-1)), although colonies with single YBD lesions have become infected in multiple locations. Most (85%) colonies identified with YBD in 1999 and 2000 were still affected in 2003, and these corals have lost a mean of 60% of their living tissue. Mortality from YBD is being compounded by black band disease, white plague and other syndromes; bioeroding sponges, macroalgae, cyanobacteria and other competitors have colonized tissue-denuded skeleton, minimizing the likelihood of resheeting. The deteriorating health of M. annularis is of particular concern, as these are the dominant corals on these reefs, the largest (2 to 3 m diameter and height) and presumably oldest colonies were infected with YBD more frequently than small colonies, and no recruitment has been observed. YBD is causing extensive mortality to key reef-building taxa in a remote location where anthropogenic stressors are minimal. Additional research on causes of YBD, mechanisms of infection, and strategies to mitigate YBD is needed; otherwise, M. annularis may suffer a fate similar to that of the Atlantic acroporids.

Late development of homoeothermy in mink (Mustela vison) kits - a strategy for maximum survival rate*

The objective of this study was to establish the age at which mink kits develop functional homoeothermy. The investigation was based on the hypothesis that in this species with very immature neonates, late development of homoeothermy may be an adaptation to economize with energy. Measurements of heat production (HE) by means of indirect calorimetry lasting 3 h were performed on neonatal kits and kits from 1 to 54 days of age. Both single kits and groups of 4-5 huddling kits were kept at 15 degrees C (L) or 30 degrees C (H) [from 35 days onwards at 25 degrees C (H)]. Animals were weighed before and after the experiments and evaporative water losses (EWL) were calculated. When exposed to L temperature, single kits responded with a very low HE until 29 days of age, and groups of kits until 14 days of age. It was not until they reached an age of approximately 6 weeks that single kits showed a clear thermoregulatory response to the L temperature by increased HE, whereas groups of kits showed increased HE from 29th day onwards. When kept at H temperature, HE was low initially, but all kits showed elevated HE at 8 days of age, and the metabolic rate was similar for single kits and kits huddling in groups. Evaporative water losses was higher among single than among groups of kits and slightly lower but more variable for animals at L than at H temperature. It was concluded that mink kits develop functional homoeothermy at an age of close to 6 weeks and that the failure of very young kits to thermoregulate is an adaptation mechanism in order to economise with their very limited body energy reserves.

Effects of body surface area estimates on predicted energy requirements and heat stress

The 0.09 x W(0.67) equation (where W = weight in kilograms) used to estimate body surface area (SA) in cattle energy requirements models was developed using measurements of sheep that weighed between 24 and 38 kg. The SA estimates it produced were compared with those of the equation 0.14 x W(0.57), based on Holstein cattle weighing 41 to 617 kg. The estimate of SA produced by the first equation was 23% greater for a 650-kg cow than that obtained by the second equation. The impact of SA estimates on thermal comfort range and development of cold and heat stress effects was calculated, using a thermal balance model, for a 600-kg cow producing 35 kg/d. Predicted metabolic heat production increment at -10 degrees C ambient temperature with 0.5 m/s wind velocity was 0.44 Mcal/d and 1.21 Mcal/d by the first and second equation, respectively. Predicted lower critical temperature (LCT) was -8.7 degrees C by the first equation and -0.6 degrees C by the second equation, an 8 degrees C difference. The LCT difference between SA estimates increased from 4.6 to 9.4 degrees C, with milk production rising from 10 to 45 kg/d. By the first equation, skin nonevaporative heat loss started to decrease at 15 degrees C and became close to nil at and ambient temperature of 35 degrees C, whereas by the second equation, respective values were 10 degrees C and 39 degrees C, a 5 degrees C shift in the estimated temperature at which thermal stress would start developing. The larger SA and skin water loss predicted by the first equation reduced by 50% the respiratory heat loss involved in maintenance of thermal balance at higher temperatures for a 600-kg cow. The second equation seems preferable for Holstein SA estimation since it is based on Holstein cattle data. It provides more adequate estimates of energy requirement in the cold and of heat stress relief needs for Holstein cattle.

Host selection by Anopheles arabiensis and An. quadriannulatus feeding on cattle in Zimbabwe

In the Zambezi valley, mosquito females of the Anopheles gambiae Giles complex (Diptera: Culicidae) were collected from a hut containing pairs of cattle distinguishable by known DNA markers. DNA was extracted from the blood-fed mosquito abdomens and primer sets for ungulate and mosquito DNA loci were used to identify the mosquito sibling species and individual host source(s) of their bloodmeals. The 67 mosquitoes comprised a mixture of An. arabiensis Patton (31%) and An. quadriannulatus Theobald (69%). DNA from one or both of the cattle present in the hut was detected in 91% of samples. When the hut contained an adult and a calf, the percentage of bloodmeals from the adult, the calf and adult + calf were 58%, 27% and 15%, respectively; the trend towards meals from the adult host was consistent but not always significant. When the pair of cattle comprised two adults of roughly equal size and age, then mosquitoes generally showed no significant bias towards feeding from one individual. There was no significant difference in the pattern of host selection made by An. arabiensis and An. quadriannulatus but the former had a significantly higher percentage (20%) of mixed meals than An. quadriannulatus (9%). These two members of the An. gambiae complex appear to be less selective in their choice of cattle hosts compared to day-active Diptera such as tsetse and Stomoxys, possibly because the hosts are generally asleep when Anopheles are active and there is therefore less selective pressure to adapt to host defensive behaviour. The slight bias of Anopheles towards older and/or larger cattle may be related to the host's larger surface area.

Does size really matter? Effects of fish surface area on the settlement and initial survival of Lepeophtheirus salmonis, an ectoparasite of Atlantic salmon Salmo salar

The effect of the size of the surface area of a fish host on settlement and initial survival of Lepeophtheirus salmonis (Krøyer, 1837) was determined. Atlantic salmon Salmo salar L. of various sizes-small (43 +/- 4 g), medium (173 +/- 32 g) and large (644 +/- 62 g)-were initially examined to ascertain their respective body surface area, excluding gill surface. The initial examination showed a size-dependent body to fin area ratio, with the fin area of small fish representing 34% of the total body area and the fin area of medium and large fish representing 26 and 23%, respectively. Regression analysis of the body weight and standard length against total body surface area gave a good correlation and high R2 values. Two simultaneous experimental infections with approximately 7,000 copepodids of L. salmonis were carried out on fish populations of mixed sizes consisting of 30 small fish, 10 medium-sized fish and 5 large fish, with an approximate total surface area per size group of 2700 cm2. Higher numbers of parasites were found on the small size group, which also had the highest parasite density, with 0.25 and 0.45 parasites cm(-2). Comparison of samples of 5 fish per experimental group revealed that the larger fish had the highest mean numbers of parasites, but the smaller fish still retained the highest density. There was a statistically significantly higher settlement on the fins than on the remainder of the body surface in all size groups. Highest numbers of parasites were particularly found on the dorsal and pectoral fins. Examination of the surface surface area revealed that the dorsal fin had the greater parasite density, with >2 parasites cm(-2) in all fish size groups. These data provide insight into the effects of the amount of host surface area available on parasite settlement and survival, and highlight the potentially increased susceptibility of farmed salmon smolts to infection of this ectoparasite.

Minimum space allowance for transportation of swine by road

Space allowance for animals in transit is a consistent concern in many countries that are developing codes of practice and regulations to assure humane treatment of food producing animals. The minimum space allowance requirements for a broad size range of swine in transit has not been well described or scientifically substantiated. A maximal loading pressure recommendation for pigs weighing from 5 to 250 kg was derived by a consultative process involving the swine transportation industry, animal welfare groups, and a literature review. The recommended maximal loading pressure under ideal conditions for swine loaded in groups can be described as a hoerl model y = (37.53)(0.9969)w(W0.5008), where y = loading pressure in kg body weight/m2 and W = average animal body weight in kilograms.

Usefulness of the indexed effective orifice area in the assessment of subaortic stenosis in the dog

To evaluate the usefulness of the Doppler-derived effective orifice area (EOA) in assessing the hemodynamic severity of subaortic stenosis (SAS) in dogs, 2-dimensional and Doppler echocardiographic examinations were performed in 16 dogs with SAS, 22 normal adult dogs, and 22 normal puppies. The EOA was calculated by the continuity equation using the stroke volume determined in the right ventricular outflow tract. The EOA was significantly lower (P < .001 ) in the SAS dogs (0.76+/-0.45 cm2) and in the normal puppies (1.58+/-1.00 cm2) than in the normal adult dogs (2.34+/-0.78 cm2). The EOA indexed for body surface area (IEOA) was significantly lower (0.89+/-0.48 cm2/m2) in SAS dogs than in the normal puppies (2.42+/-0.85 cm2/m2) or adults (2.22+/-0.76 cm2/m2). The normal dogs (adults and puppies) had an IEOA of > or =1.25 cm2/m2. Among the demographic and echocardiographic parameters measured in this study, only the indexed EOA was significantly associated (P = .03) with the occurrence of adverse events (eg, syncope, episodic weakness, ventricular arrhythmias). This study demonstrates the usefulness and feasibility of the indexed EOA as measured by Doppler echocardiography for noninvasive assessment of SAS severity in dogs.

Cold-hardiness and evaporative water loss in hatchling turtles

North American turtles hatch in late summer and spend their first winter either on land or underwater. Adaptations for terrestrial overwintering of hatchlings in northern regions, where winter thermal and hydric regimes are harsh, have not been systematically investigated in many species. We measured intrinsic supercooling capacity, resistance to inoculative freezing, and desiccation resistance in hatchlings of terrestrial and aquatic turtles collected from northern (Terrapene ornata, Chrysemys picta bellii, Kinosternon flavescens, Chelydra serpentina) and southern (Chrysemys picta dorsalis, Trachemys scripta, Sternotherus odoratus, Sternotherus carinatus) locales. Supercooling capacity was estimated from the crystallization temperature of turtles cooled in the absence of external ice nuclei. Mean values ranged from -8.1 degrees to -15.5 degrees C and tended to be lower in terrestrial hibernators. Inoculation resistance was estimated from the crystallization temperature of turtles cooled in a matrix of frozen soil. These values (range of means: -0.8 degrees to -13.6 degrees C) also tended to be lower in the terrestrial hibernators, especially C. picta bellii. Mean rates of evaporative water loss varied markedly among the species (0.9-11.4 mg g(-1) d(-1)) and were lowest in the terrestrial hibernators. Most species tolerated the loss of a modest amount of body water, although half of the sample of S. carinatus died from desiccation. In general, turtles did not regain lost body water from wet soil, and immersion in free water was required for rehydration. Therefore, desiccation resistance may be an important adaptation to terrestrial hibernation. Resistances to inoculative freezing and desiccation were directly correlated, perhaps because they are governed by the same morphological characteristics.

Comparison of minimum space allowance standards for transportation of cattle by road from 8 authorities

Space allowance for animals in transit is a consistent concern in many countries developing codes of practice and regulations to assure humane treatment of food producing animals. Describing minimum space allowance requirements for cattle in transit has proven to be difficult, as the space required increases as the animal grows. Loading pressure, defined as weight of live animal per unit area, has proven to be a clear method of communicating with transporters and inspection staff what the maximum safe stocking limit is based on individual animal weight. The loading density recommendations in the Canadian code of practice for beef cattle are compared with other standards by using loading pressure charts as a visual aid. Loading pressure charts are recommended in preference to a tabular format to describe the minimal space allowed per animal for cattle transported by road.

Does allogrooming serve a hygienic function in Cercocebus torquatus lunulatus?

To test the hygienic functional hypothesis of allogrooming in the white-crowned mangabey (Cercocebus torquatus lunulatus), we analyzed the distribution of such behavior over the body surface in the individuals of two captive groups of this species (N = 9 and N = 8). To sample the data, we used focal animal sampling and continuous recording. Before analyzing the data, we measured a representative subject in order to calculate the body surface area occupied by each site, defined accessibility rigorously (distinguishing among three categories of sites: easy to reach, difficult to reach, and inaccessible), and tested empirically the classification proposed. To determine whether allogrooming was likely to concentrate on the body sites with accessibility problems, we ran three successive analyses, each of with was increasingly specific: grouping types of sites, analyzing each site separately, and analyzing each subject's reception profile. The results obtained show that in both groups inaccessible sites received more allogrooming than predicted by their actual surface area; sites that were difficult to reach received an amount of allogrooming proportional to the body surface area they occupied, and those easy to reach received less allogrooming than expected. This complementarity between the distribution of auto- and allogrooming is consistent with the hygienic functional hypothesis of allogrooming. However, not all inaccessible sides nor those difficult-to-reach were allogroomed equally: Allogrooming concentrated primarily on dorsal and caudal regions, whose care is incompatible with a ventral/ventral orientation between groomer and groomee. The strong distributional selectivity of allogrooming and the interindividual variability in preferred allogrooming sites suggest that the hygienic functional hypothesis cannot fully account for all the aspects of the corporal distribution of such behavior. Thus, in support of the multifunctional nature of allogrooming, we conclude that there must be more than cleaning involved in Cercocebus torquatus lunulatus' allogrooming.

Echocardiographic parameters in training compared with non-training greyhounds

Echocardiographic parameters were compared between training and non-training greyhound dogs. When indexed to body weight there was a statistically significant increase (p < 0.05) in the interventricular septal thickness (systole) and when indexed to body surface area there were increased interventricular septal (systole) and left ventricular free wall measurements (systole) in training compared with non-training greyhounds. When each gender was analyzed separately and echocardiographic parameters were indexed to body size, both genders had an increase in the interventricular septal thickness (diastolic in the female, systolic in the male) in the training compared with non-training greyhounds. In male training greyhounds there was additionally an increase in the left ventricular internal dimension (systole) and free wall thickness (systole) when echocardiographic parameters were indexed to body surface area compared with non-training greyhounds (p < 0.05). The results indicate that certain training greyhound echocardiographic parameters are larger than non-training greyhound echocardiographic parameters. The potential effects of training, body size and gender should be considered when interpreting echocardiographic parameters in populations of greyhounds.

Use of body surface area to calculate chemotherapeutic drug dose in dogs: II. Limitations imposed by pharmacokinetic factors

Anticancer drug dosages that specify the maximum dose and minimum dosing interval that are tolerated in a population of dogs are commonly recommended. Because the differences between the effective and toxic doses of most cancer chemotherapeutics is slight, it is important to achieve therapeutic concentrations in tumor tissues at the same time that concentrations in nontarget tissues are minimized. In order to determine the dosage regimen that will most likely accomplish these goals, similar drug concentrations must be achieved in all patients dosed according to a specific regimen. Dosing based on body surface area (BSA) is generally used in an effort to normalize drug concentrations. This is because it is well recognized that measures of many physiologic parameters that are responsible for drug disposition, including renal function and energy expenditure, can be normalized by use of BSA. However, there is substantial evidence that drug disposition is not always proportional to BSA. Differences in distribution, metabolism, and excretion pathways may preclude dose extrapolation among species or among individuals within a species based on BSA. Moreover, genetic differences in drug metabolism are well recognized in humans and in laboratory animals, and it is likely that similar differences exist among breeds of dogs. A review of the pharmacokinetic disposition of several cancer chemotherapeutics suggests that studies are needed to determine the most effective method to achieve equivalent anticancer drug concentrations in diverse veterinary patients.

Use of body surface area (BSA)-based dosages to calculate chemotherapeutic drug dose in dogs: I. Potential problems with current BSA formulae

The dose of most cancer chemotherapeutic drugs administered to dogs is calculated on the basis of estimated body surface area (BSA); however results of some chemotherapy trials have revealed that this dosing method increases toxicosis in small dogs. The current formula used to estimate BSA in dogs may be inaccurate or the assumption that BSA correlates with chemotherapeutic drug exposure may be unfounded. Results presented in this review suggest that canine BSA estimates may be inaccurate because the values for the constant (K) and exponent (a) in the formulae (BSA = K.Wa) are incorrect or because a linear parameter such as body length is lacking from the formulae. Results that suggest the relationship between BSA and the physiologic/pharmacologic factors that influence drug exposure may not be closely correlated are also presented. Studies are warranted to determine whether there are dosing methods that normalize chemotherapeutic drug toxicity in dogs.

Surface area to volume relationships of snakes support the use of allometric scaling for calculating dosages of pharmaceuticals

Metabolic scaling is used to estimate pharmaceutical dosages for snakes because few pharmacokinetic studies have determined optimum dosages. The question arose as to the validity of the assumption of metabolic scale among snakes because they have such a cylindrical shape. The surface area to volume relationships of a group of animals is a major portion of the metabolic scaling exponent of 0.75. An assumption inherent in scaling pharmaceutical dosages for snakes is that there is not a shape change with a size change, or that scaling of the surface area to volume has an exponent of 0.66. One hundred forty snakes, 106 Colubridae and 34 Boiidae, were weighted, their volume was determined by water displacement, and the snakes were measured. Geometric formulas were used to calculate surface area and volume of each snake. Surface area to volume relationship was nearly isometric, with a scaling exponent of 0.64, supporting the use of metabolic scaling for estimating pharmaceutical doses.

Indirect measurement for body surface area of cotton rats

The body surface areas (BSAs) of 42 cotton rats (21 females weighing 29.08 to 169.60 g, and 21 males weighing 18.93 to 168.03 g) were measured. From these areas and body weights (BW), the equation, BSA (cm2) = 47.66 + 2.476 x BW (g) -0.006 x BW (g)2, was derived. To verify the applicability of the equation, the BSAs of another 19 animals (12 females weighing 29.08 to 169.60 g, and 7 males weighing 19.27 to 167.32 g) were calculated and the values compared with the measured BSAs. The correlation between calculated and measured BSAs was significant (r = 0.995, P < 0.01). Therefore, this equation can be used to calculate cotton rat BSA.

Estimation of the total surface area in Indian elephants (Elephas maximus indicus)

Twenty-four adult Indian elephants (Elephas maximus indicus) of both sexes and different ages and weights, belonging to the Temple Devaswoms, the Forest Department of the Government of Kerala and the Gemini Circus formed the experimental subjects from which formulae were derived to predict the total surface area from either body measurements or areas of individual regions. Several models, using the parameters studied either singly or in combination, were tried independently for males and females and also for adults irrespective of sex. The best prediction of total surface area (S) in m2 was obtained for adults irrespective of sex by using the two parameters, the height at the shoulders (H) in m and forefoot pad circumference (FFC) in m in the formula S = -8.245 + 6.807H + 7.073FFC. No significant improvement in the accuracy of prediction resulted from the use of the independent best fit formulae for males and females. The conventional method of using the exponential of body weight (kg) for predicting surface area was not found to yield an equivalent accuracy in these animals.

Propulsion of a fin whale (Balaenoptera physalus): why the fin whale is a fast swimmer

Measurements of an immature fin whale (Balaenoptera physalus), which died as a result of entrapment in fishing gear near Frenchmans Cove, Newfoundland (47 degrees 9' N, 55 degrees 25' W), were made to obtain estimates of volume and surface area of the animal. Detailed measurements of the flukes, both planform and sections, were also obtained. A strip theory was developed to calculate the hydrodynamic performance of the whale's flukes as an oscillating propeller. This method is based on linear, two-dimensional, small-amplitude, unsteady hydrofoil theory with correction factors used to account for the effects of finite span and finite amplitude motion. These correction factors were developed from theoretical results of large-amplitude heaving motion and unsteady lifting-surface theory. A model that makes an estimate of the effects of viscous flow on propeller performance was superimposed on the potential-flow results. This model estimates the drag of the hydrofoil sections by assuming that the drag is similar to that of a hydrofoil section in steady flow. The performance characteristics of the flukes of the fin whale were estimated by using this method. The effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized. Frictional effects in particular were found to reduce the hydrodynamic efficiency of the flukes significantly. The results are discussed and compared with the known characteristics of fin-whale swimming.

Determination of body surface area in neonatal swine

The body surface area of 30 neonatal pigs of both sexes, weighing 445--1,976 g, were determined by the direct skinning technique. The range of measured body surface area values was 635--1,400 cm2 (mean = 895.1 cm2). The regression line, fitted to a scatter diagram and calculated by the least square method, was found to be Y = 337.2 + 0.553X; where X was body weight expressed in grams and Y was body surface area expressed in square centimeters.

Measurement of guinea pig body surface area

The body surface area (BSA) of 50 adult 2/N guinea pigs of both sexes and varying age was measured by the skinning and paper weight technique, or calculated from two equations in which the animals' weight (W) alone or the weight and length (L) were known. The equations BSA = W2/3 x 8.054 and BSA = W0.425 x L0.725 X 3.545 were developed by the method of least squares. The differences between the values obtained by measurement and those obtained by either of the calculation methods were not statistically significant. Differences because of sex and age were also not significant.

[Dynamics of early changes in the white component of the peripheral blood of whole-body irradiated cattle]

Some new findings regarded the dynamics of the changes in the white component of peripheral blood, particularly at early intervals in the case of three clinically differing doses of ionizing radiation were obtained. At the highest dose early nonspecific leucocytosis was recorded only six hours after the exposure. Significant neutrophili occurred in the case of all three doses beginning from the sixth hour. With the highest dose it had the shortest duration and highest values, and at the smallest dose the opposite was the case. In the case of the highest dose leucopenia sets in after 24 hours, and in the case of the other doses not until after 36 hours. Lymphopenia appears already after 6 hours, the consequences according to the doses, however, manifest themselves only after 12 hours. In all three groups leucopenia and lymphopenia have a constant character. It was confirmed that the changes in the white blood component were the most typical response to the exposure to ionizing radiation, and orientation and special criteria have been found for the estimation of the consequences of the forms of irradiation on the basis of numerical changes of leucocytes, lymphocytes, and neutrophilic granulocytes within 72 hours after the exposure.

[Pathomorphological findings in irradiated cattle]

There is a description of the finding in whole-body irradiated young cattle exposed to 60Co in the doses of 3.7 and 2.0 J kg-1 (370 and 200 rad). The principal picture is a hemorrhagic diathesis localized above all in the permanently mechanically active organs and parts of the skeletal muscles. The degree of the regeneration of lymphoid tissue was dependent on the length of survival and on the amount of absorbed dose.

[Clinical changes in whole-body irradiated cattle]

Clinical manifestations of an acute radiation sickness in groups of heifers of the age of seven to nine months, irradiated with a multipoint spatial 60Co source with the doses of 3.7, 2.0, and 1.2 J per kg-1 (450, 250, and 150 R) were studied. Those doses evoked different stages of clinical manifestations, which made it possible to differentiate severe, medium, and light forms of the radiation sickness. The different forms vary with the intensity of the clinical manifestations, with the length of survival, and, above all, with the length of latent stage. The severe form had mostly a lethal course with the exit between the 15th to 19th day, in the case of the medium form the length of survival increases to the 25th to 28th day, and the light form showed no significant clinical manifestations.

A technique for the description of projections of internal organs onto the exposed surface of animals

The need for exact knowledge of the projections of internal organs onto the surface of animals is emphasized, for clinical veterinary medicine as well as for hunting purposes. A method is described for outlining the projections of dissected anatomical structures onto the exposed surface, on a photograph of the undisturbed animal in a natural standing position.