Is It Possible to Mitigate Fear of Fireworks in Dogs? A Study on the Behavioural and Physiological Effects of a Psychoactive Supplement

Canine fear of fireworks is a common problem worldwide, with serious implications for the welfare of both dogs and their owners. Therapies for the problem are available, and herbal and nutraceutical agents are increasingly suggested by professionals; nonetheless, studies on their real efficacy in reducing firework fear are lacking. In a randomised, double-blinded, placebo-controlled study, 44 dogs (25 in the "supplement" group and 19 in the "placebo" group) completed a long-term continuous treatment with either a supplement made of tryptophan, valerian, and passiflora or a placebo, including two real exposures to fireworks (on 2020 Christmas and 2021 New Years' Eve, after 42 and 48 days of treatment, respectively). Owners of both groups received the same general environmental management and food/toy offering recommendations for trying with their dogs on those nights. Behavioural (measured by LSSS-Lincoln Sound Sensitivity Scale and PANAS-Positive and Negative Activation scale, as rated by the owners) and stress (measured via salivary cortisol measures) reactions were evaluated. Significantly greater fear decrease (LSSS) was recorded in the "supplement" dogs, as compared to the "placebo" group. Cortisol dosages on New Year's Eve ("noisy" night) were in line with behavioural results; "supplement" dogs showed a smaller increase in the stress response from 22:30 to 00:30 h on New Year's Eve and a greater decrease in their stress response from 02:30 h to 10:30 h on New Year's Day compared to "placebo" dogs. Smaller cortisol levels were also shown by "supplement" dogs than "placebo" dogs on a controlled "quiet night" (27th December). Owners' rates on PANAS remained stable during the whole period of therapy for both groups. The evaluated supplement, a combination of tryptophan, valerian, and passiflora, showed satisfactory results and rare side effects when treating dogs fearful of fireworks.

Metal and semimetal loadings in sediments and water from mangrove ecosystems: A preliminary assessment of anthropogenic enrichment in São Tomé island (central Africa)

Mangroves act as buffer areas for marine systems, providing a barrier to contamination from continental sources by retaining metal pollutants. This study evaluates metal and semimetal contamination in the water column and sediments of four mangroves located on the volcanic island of São Tomé. Several metals had a widespread distribution, with occasional high concentrations, linked to potential sources of contamination. However, the two smaller mangroves, located in the northern part of the island, tended to have high metal concentrations. Arsenic and chromium concentrations were particularly concerning, particularly if we consider this is an isolated and non-industrialized island. This work highlights the need for further assessments and a better understanding of processes and implications of metal contamination in mangroves. This assumes a particular relevance in areas that have particular geochemical compositions (i.e., volcanic origin) and in developing countries, where people often rely directly and heavily on resources obtained from these ecosystems.

Phenotypic diversity of starch granules in cassava germplasm

Demand for the development of cassava varieties with different native starches has guided the search for these characteristics in the germplasm of Manihot esculenta Crantz. Therefore, the objective of this study was to estimate the genetic diversity of cassava accessions for root and starch granule characteristics to guide the future industrial application of this species. Starches from 56 accessions were evaluated for the number of granules in 1 g of starch (NTG), area (AG, μm²), length (LG, μm), width (WG, μm), starch granule roundness (Round), dry matter content in the roots (DMC, %), pulp color (PulCo), and cyanogenic compounds (HCN). Images captured by light microscopy were used to determine the average phenotypic values, and these were further analyzed by principal component analysis (PCA) considering mixed data (quantitative and qualitative). Significant differences between the cassava accessions for all traits measured revealed wide variability in starch granule characteristics. Four diversity groups with better fitness for the classification of cassava accessions based on PulCo were identified, in comparison with HCN. Accessions with differential starch characteristics were identified, and crossings for the generation of segregating populations in order to obtain table and industry varieties have been proposed.

Decrease in oxidative stress and histological changes induced by physical exercise calibrated in rats with osteoarthritis induced by monosodium iodoacetate

OBJECTIVE

The purpose of this study was to evaluate the effects of impact exercise on the joint cartilage of rats with osteoarthritis (OA) induced by monosodium iodoacetate (MIA).

METHODS

Eighteen male rats were divided into three groups of six animals each: control, OA, and OA plus exercise (OAE). The OAE group trained on a treadmill for 8 weeks. Afterward, the right joints of the animals were washed with saline solution and joint lavage was used for biochemical analyses of myeloperoxidase (MPO) and enzyme superoxide dismutase (SOD) activities and total thiol content. The same limb provided samples of the articular capsule for analyses of MPO activity and total thiol content. The left joint was used for histological analysis.

RESULTS

Our results indicate that MPO activity was increased in both OA groups in the lavage as well as the articular capsule, regardless of exercise status. SOD activity was increased in animals with OA, especially in the animals that had run on the treadmill. On the other hand, thiol content in the articular capsule and joint lavage decreased in the OA group, while the OAE group had values similar to those of the control group. The histological data indicate that animals that were submitted to running exercise showed a higher preservation rate of proteoglycan content in the superficial and intermediate areas of the joint cartilage.

CONCLUSION

Our results show that physical training contributes to the preservation of joint cartilage in animals with OA and to increase the defense mechanism against oxidative stress.

Inefficacy of piracetam in the prevention of painful crises in children and adolescents with sickle cell disease

Analgesia and hydration remain the only safe treatment for painful crises of sickle cell disease; hydroxyurea is effective, but the toxicity is still a problem. Piracetam is a nootropic drug that has reportedly been effective and non-toxic in sickle cell patients, but most studies were not placebo-controlled and included a small number of patients. The present study evaluated the drug in a double-blind crossed placebo-controlled clinical trial in 73 children and adolescents suffering from moderate to severe painful crises for 13 months. Information regarding frequency and severity of pain was acquired through monthly clinical evaluation, visits and house calls, and 4,300 weekly questionnaires filled out by the patients in their domiciles. A monthly pain score was calculated for each patient. Pain was the most frequent adverse manifestation of the disease stressing its significant bio-psycho-social impact. Although nearly all patients and relatives reported a better clinical course throughout the whole study, the drug was ineffective in the prevention of painful crises. This placebo effect may be ascribed to an unplanned and unsystematic 'cognitive-behavioural' management of the children. The pain score in the second semester of the study - both in the experimental and in the control groups - was significantly smaller than that in the first semester. In conclusion, piracetam was found to be ineffective in the prevention of painful crises; a powerful placebo effect due to adequate patient care was demonstrated.

[Prevalence of canine filariasis by Dirofilaria immitis and Dipetalonema reconditum in Maceió, Alagoas State, Brazil]

A survey on the prevalence of Dirofilaria immitis and Dipetalonema reconditum was conducted in 1,519 dogs from Maceió and two coastal areas in the State of Alagoas, Northeast Brazil, from 1995 to 1999, by testing for microfilariae in blood. All blood samples were from exclusively domiciled dogs with a known history, showing that the infections were autochthonous, confirming transmission of canine filariasis in these areas. In Greater Metropolitan Maceió, 15 (1.3%) microfilaremic dogs were detected with D. immitis and 15 (1,3%) with D. reconditum. In the southern coastal area there was an estimated prevalence of 12.7% for D. immitis. D. immitis and D. reconditum microfilaria were 298.1 micrometer and 249.2 micrometer long and 7.3 micrometer and 4.4 micrometer wide, respectively. A Witness immunotest that detects D. immitis antigen was used to confirm parasitological results and reveal occult dirofilariasis cases. Of the total 6,579 females examined, 8 (0.1%) Culex quinquefasciatus were observed to be naturally infected with D. immitis larvae. These results proved dirofilariasis transmission in Maceió and demonstrated D. reconditum in the same geographic area.

[Bancroftian filariasis in urban areas of Alagoas State, Northeast Brazil: study in the general population]

In order to assess the present status of lymphatic filariasis in Alagoas State, Brazil, hemoscopic surveys were carried out in the human population of the three different physiographic regions of the State. Blood samples were collected by thick smear technique taken after 10:00 p.m. From a total of 101 cities of the State, 10 were randomly selected, Bancroftian filariasis was only found in Maceió, the capital of Alagoas State. In a cross-sectional survey conducted among the general population of 4 neighborhoods in the city, 10,973 individuals were examined, 226 were microfilaraemic with prevalence in the city neighborhoods ranging from 0 to 5.4%. Prevalence rates and microfilariae density were significantly higher in males. Among the examined inhabitants born out of Maceió, microfilariae carriers had lived a significantly longer time in endemic areas than the amicrofilaraemic subjects. Based on the data obtained in the present study, measures to avoid expansion of bancroftian filariasis in the region were established.

The microfilarial periodicity of Wuchereria bancrofti in north-eastern Brazil

The periodicity of Wuchereria bancrofti microfilariae (mff) in peripheral blood was analysed in 42 microfilaraemics living in Maceió, in Alagoas state, north-eastern Brazil. Nine blood samples were collected from each subject, over a 24-h period, and two quantitative (60-microliter) thick smears were prepared from each sample. Although all the subjects had detectable microfilaraemias from 23.00 hours to 06.00 hours, no mff could be detected in most (71.4%) of the smears prepared from samples collected at 15.00 hours. Samples collected during the day, at 15.00 hours, contained 170 times fewer mff/microliter than those collected at 01.00 hours, when microfilaraemias were generally most intense. For diagnosis of bancroftian filariasis in Maceió, blood samples should be collected between 22.00 and 03.00 hours, when microfilarial counts will be at least 90% of the peak counts. The circadian variation observed was independent of the subject's gender and microfilarial density. Mathematical analysis, using a simple harmonic-wave model, indicated a periodicity index of 127.6 and that maximum microfilarial densities occurred at 00.51 hours, confirming the nocturnal pattern of microfilaraemia in the study area.

Lymphatic filariasis in Brazilian urban area (Maceió, Alagoas)

A cross-sectional survey conducted among evening students was used to determine the prevalence of Wuchereria bancrofti infection in Maceió, capital of the State of Alagoas, northeast Brazil. A single thick-blood smear was used, being collected between 10 p.m. and 12 a.m. From a total of 29,551 students enrolled at evening elementary schools in the 33 city sectors, 16,569 (56.4%) were random selected for inclusion in the study. From those, 10,857 (65.5%) were interviewed and examined and 73 (0.7%) were found to have microfilaraemia. Autochthonous W. bancrofti carriers live in 10 of the 33 city sectors, suggesting a focal distribution. Moreover, 84% of infections were diagnosed among 29% of all students examined, inhabiting three contiguous sectors at the city central area, presenting infection rates up to 5.3%. Students living in city sectors with prevalence of microfilariae carriers greater than 1% were found to have a higher risk for infection when compared to students from the rest of the town [Relative Odds (RO) 12.8, 95% CI 6.7-25.1]. Eleven positive individuals from non endemic areas were living in Maceió for more than 10 years; time of residence in the area was a major risk factor for infection among students not born in the region (p < 0.01). Regarding sex, male students presented a higher proportion of positive (RO 1.7, 95% CI 1.1-2.9).

Bancroftian filariasis in Maceio, state of Alagoas, Brazil: Observations on Culex quinquefasciatus after blood feeding on individuals with different densities of microfilariae in the peripheral blood stream

Females of laboratory-reared Culex quinquefasciatus were allowed to take blood meals on individuals with low (1-100 microfilariae/ml of peripheral blood), moderate (101-500 microfilariae/ml), and high (> 500 microfilariae/ml) microfilaremia. The mosquitoes ingested 1.39-3.80 microl of blood and infective third-stage (L3) larvae were first recorded 13-14 days after the infecting blood meal. The number of microfilariae ingested by mosquitoes was proportional to the density of microfilariae in the peripheral blood of the human subjects, but with a concentration factor of up to 6.5 times the expected number. Survival of mosquitoes was not influenced by the density of microfilariae in the peripheral blood of infected individuals. Infectivity indices were proportional to microfilaremia in human subjects. The number of L3 larvae/female (intensity of infection) was not influenced by individual microfilaremia. The highest vector efficiency and the best experimental infection index were recorded in mosquitoes that blood fed on individuals with moderate microfilaremia. The results are discussed in relation to the transmission on Bancroftian filariasis in the study area.

Autoradiographic thyroid evaluation in short-term experimental diabetes mellitus

Previous studies have shown that in vitro thyroid peroxidase (TPO) iodide oxidation activity is decreased and thyroid T4-5'-deiodinase activity is increased 15 days after induction of experimental diabetes mellitus (DM). In the present study we used thyroid histoautoradiography, an indirect assay of in vivo TPO activity, to determine the possible parallelism between the in vitro and in vivo changes induced by experimental DM. DM was induced in male Wistar rats (about 250 g body weight) by a single i.p. streptozotocin injection (45 mg/kg), while control (C) animals received a single injection of the vehicle. Seven and 30 days after diabetes induction, each diabetic and control animal was given i.p. a tracer dose of 125I (2 microCi), 2.5 h before thyroid excision. The glands were counted, weighted, fixed in Bouin's solution, embedded in paraffin and cut. The sections were stained with HE and exposed to NTB-2 emulsion (Kodak). The autohistograms were developed and the quantitative distribution of silver grains was evaluated with a computerized image analyzer system. Thyroid radioiodine uptake was significantly decreased only after 30 days of DM (C: 0.38 +/- 0.05 vs DM: 0.20 +/- 0.04%/mg thyroid, P < 0.05) while in vivo TPO activity was significantly decreased 7 and 30 days after DM induction (C: 5.3 and 4.5 grains/100 micron 2 vs DM: 2.9 and 1.6 grains/100 micron 2, respectively, P < 0.05). These data suggest that insulin deficiency first reduces in vivo TPO activity during short-term experimental diabetes mellitus.

Open clinical study of the efficacy and safety of terbinafine cream 1% in children with tinea corporis and tinea cruris

BACKGROUND

Topical application of antifungal agents is considered the treatment of choice for dermatomycoses. Most of the available drugs are fungistatic, requiring long term treatment to prevent relapses. Terbinafine is a synthetic antifungal agent that, because of its fungicidal action, provides high cure rates and low relapse rates after short periods of treatment.

METHODS

Ninety-seven children ages 2 to 15 years with a suspected diagnosis of tinea corporis and/or tinea cruris were enrolled in this open trial. After mycologic assessment to confirm diagnosis (culture and direct microscopy) terbinafine 1% cream was applied once daily during 1 week. Clinical and mycologic assessments were made at the baseline visit and on Days 7, 14 and 21. Efficacy assessment was based on 88 children (9 patients excluded by protocol violation).

RESULTS

Therapy was considered effective in 92.0% (81 of 88) of patients (complete clinical and mycologic cure or mycologic cure with minimum signs and symptoms or clinical improvement, > or = 50%). Tolerability was assessed in 97 patients on an intention-to-treat basis. Adverse reactions were itching 3% (3 of 97), itching associated with erythema exacerbation 1% (1 of 97) and contact dermatitis 1% (1 of 97).

CONCLUSION

Terbinafine 1% cream appears to be an effective and well-tolerated treatment for tinea corporis and tinea cruris in children.

A comparison of two Brazilian populations of Culex quinquefasciatus (Say, 1823) from endemic and non-endemic areas to infection with Wuchereria bancrofti (Cobbold, 1877)

Culex quinquefasciatus is known to be an efficient insect host of Wuchereria bancrofti. In Brazil Cx. quinquefasciatus is widely distributed throughout the country and is often abundant in and around human habitations. In contrast, Bancroftian filariasis is limited to three foci in Brazil. Experiments were undertaken to compare the vector capacities of Cx. quinquefasciatus originating from Maceió (Alagoas), one of the endemic areas of W. bancrofti infection in Brazil, and Belo Horizonte (Minas Gerais), a non endemic area. Laboratory-reared Cx. quinquefasciatus were dissected 20 days after blood feeding on microfilaraemic patients. Survival rates and the number of infective larvae that developed did not differ in female mosquitoes of different origins. Thus both populations of Culex were susceptible to infection with W. bancrofti.

[Present status of bancroftian filariasis in Maceió, State of Alagoas, Brazil]

Epidemiological and entomological surveys were carried out in the human and mosquito populations in Maceió, Alagoas, in order to assess the present status of bancroftian lymphatic filariasis. Examination of thick blood smears of 10,450 students from different areas of the city revealed 0.66% Wuchereria bancrofti microfilaria carriers. The distribution of filariasis is focal in the city, 80% of the individuals with patent infection living in two neighboring areas with 1.24% and 5.25% prevalence. Parallel studies performed with samples of all age groups in the human population showed similar microfilaria prevalence rates observed previously in the student survey. However, thick blood smears taken from members of families with at least one subject with patent infection gave a prevalence six times greater suggesting, increased transmission in households. The percentage of carriers was higher in the youngest age group (< 20 years). Culex quinquefasciatus mosquitos caught at the locations where the autochthonous cases were found presented natural infection rates ranging from 0.28% to 4.62%. The combination of all these findings indicates occurrence of active transmission of W. bancrofti in the urban area of Maceió, Alagoas State. Based on these data, measures for the potential control of filariasis were planned.

In vivo relaxation times and hydrogen density at 0.063-4.85 T in rats with implanted mammary adenocarcinomas

Magnetic resonance (MR) imaging at 0.063 T, 0.17 T, 0.35 T, 2.94 T, and 4.85 T was performed in rats with implanted mammary adenocarcinomas (and in control rats) to study hydrogen density and the effects of magnetic field strength on T1 and T2 relaxation times in vivo. T1 increased by an order of magnitude and T2 decreased by a factor of two between the lowest and highest field strengths. Only about half of the increased water content of tumor, compared with that of muscle, was reflected in increased hydrogen density. The sensitivity of relaxation time change was increased at the lower field strengths. These results are of significance in understanding the effects of field strength on lesion detectability, contrast, and signal-to-noise ratio.

Albumin labeled with Gd-DTPA as an intravascular, blood pool-enhancing agent for MR imaging: biodistribution and imaging studies

Albumin is a macromolecule that remains largely confined to the vascular space after intravenous administration. Human serum albumin was paramagnetically labeled by covalently binding from nine to 18 gadolinium-DTPA (diethylenetriaminepentaacetic acid) chelates per protein molecule. This conjugate was tested in varying doses for in vivo biodistribution and effectiveness in tissue relaxation. After intravenous injection of the agent in rats, T1 relaxation times were significantly reduced in samples of the blood and in lung, heart, spleen, kidney, and brain tissue. These effects persisted at a relatively constant level for the next 30 minutes. In vivo magnetic resonance imaging of the heart and lungs of rats and rabbits confirmed the prolonged contrast-enhancing effect of the labeled albumin. These preliminary studies indicate that paramagnetically labeled macromolecules that distribute in the intravascular space may be effective for MR imaging evaluation of tissue blood volume.

EKG-gated digital subtraction angiography in the detection of pulmonary emboli

Detection of pulmonary emboli was investigated using electrocardiographically gated (EKG-gated) intravenous digital subtraction angiography (DSA) in 6 anesthetized and paralyzed dogs. Six autologous blood clots were introduced into the internal jugular vein of each dog and both conventional pulmonary angiography and EKG-gated DSA performed in frontal and oblique projections. When two observers scored any definite or equivocal embolus as positive, sensitivity was 82.1% for one and 92.9% for the other; the respective positive predictive values (PPV) were 88.5% and 65%. When only definite emboli were considered positive, sensitivity was 75% for one observer and 71.4% for the other; PPV was 100% for both. The authors conclude that DSA can demonstrate individual emboli with good sensitivity and excellent precision. If several emboli are present, EKG-gated DSA should prove highly accurate; however, care must be taken because overinterpretation is more likely with DSA than with conventional pulmonary angiography.

Nuclear magnetic resonance contrast enhancement study of the gastrointestinal tract of rats and a human volunteer using nontoxic oral iron solutions

Two dilute oral iron solutions, made from commonly available nonprescription dietary supplements, were found to enhance the gastrointestinal tract in nuclear magnetic resonance imaging of live rats and one human volunteer. The paramagnetic and pharmacologic properties of ferric ammonium citrate were more favorable than those of ferrous sulfate heptahydrate. The paramagnetic iron solutions shorten T1 and T2 relaxation times of water protons in the contrast media-filled gastrointestinal tract, producing easily observable change in NMR intensity. Because these iron solutions are available commercially and are known to be well tolerated, the clinical use of iron-containing NMR contrast agents for the gastrointestinal tract is feasible.

Nuclear magnetic resonance imaging of a fibrosarcoma tumor implanted in the rat

Fibrosarcoma tumor cells were implanted in the hind legs of 25 rats and studied from the first to the sixth week postimplantation. Nuclear magnetic resonance imaging detected all tumors and did not yield any false-positives in five control rats. The T1 relaxation values of tumors overlapped those of muscle, and the T2 values overlapped those of fat, but the combination of the two values allowed discrimination of each of the three tissues with no overlap. The difference in relaxation time between tumor and muscle could be accounted for on the basis of water content, which was approximately 14% higher in the tumors. This study confirms data from previous studies suggesting that nuclear magnetic resonance imaging is a highly sensitive modality, but that T1 and T2 values are not specific for individual pathologic conditions.

Diagnosis of peripheral pulmonary emboli by computed tomography in the living dog

Computed tomography (CT) provides a noninvasive alternative to arteriography in detecting central pulmonary thromboembolism. It is uncertain, however, if smaller, more peripheral clots can be diagnosed by means of CT because of the low spatial resolution and the possible motion artifacts that result from long exposure time. The peripheral pulmonary arteries of five dogs were embolized with boiled autologous clots. The location and size of the thromboemboli were then determined using arteriography. One dog died after embolization. In three of the four remaining dogs, CT scans, after slow intravenous injection of contrast material, showed the emboli as filling defects in the appropriate lobar and segmental arteries.

Computed tomography of the liver in rhesus monkeys following losefamate meglumine administration

Iosefamate meglumine was evaluated for potential use as a contrast agent for hepatic computed tomography (CT) in rhesus monkeys. Iosefamate meglumine in doses of 150, 300, and 450 mg I/kg was injected into four rhesus monkeys and hepatic CT attenuation values, blood iodine levels, serum enzyme levels, and hepatic histology were monitored. The hepatic CT number increased by 19 to 30 HU following a 150 mg I/kg dose and remained elevated for 15 to 45 minutes. Peak blood iodine values occurred 2 minutes postinjection but fell rapidly to less than 40% of the peak value by 45 minutes and less than 20% of peak by 4 hours. Transient elevations in serum enzyme levels were found but no histologic abnormalities were detected. Iosefamate meglumine is a potentially valuable hepatic CT contrast agent, as it produces a significant, prolonged increase in hepatic attenuation values and selectively opacifies functioning hepatocytes.

Medially deployed thoracostomy tubes: cause of aortic obstruction in newborns

It was observed that severe aortic displacement, narrowing, and obstruction can occur when thoracostomy tubes abut the mediastinum. To further investigate this previously undescribed phenomenon, aortography was performed with intraluminal pressure measurements in newborn puppies and aortograms obtained in two infant cadavers. In the puppies, when the tube tip pressed against the descending thoracic aorta, aortic pressure below that site decreased and aortic arch pressure rose. When the tube tip pressed against the ascending aorta, pressures in the aortic arch and abdominal aorta decreased. Aortography in the puppies and infant cadavers demonstrated aortic displacement, narrowing, and obstruction when the thoracostomy tubes abutted the mediastinum. The clinical consequences of malpositioned thoracostomy tubes were observed in two premature infants. When the posteromedially deployed tubes were partially withdrawn, systolic arterial pressures, which had been exceptionally low, suddenly and significantly increased distal to the tube tip. Medially deployed thoracostomy tubes may represent a potential hazard to the newborn infant.

Determination of liver, kidney, and spleen volumes by computed tomography: an experimental study in dogs

The volume of the dog's liver, kidneys, and spleen were measured by computed tomography (CT) and a water displacement method. Organ volume determination by CT is a rapid, simple procedure that is accurate to +/- 5% of the organ volume measured by water displacement. Individual measurements were reproducible to within +/- 3%. Determination of organ volume has potential importance in a variety of clinical situations.

[Pure cutaneous cryptococcosis]

The authors present one case of cutaneous cryptococcosis, which diagnosis was confirmed by histopathologic and mycologic procedures. As there has not been systemic dissemination, this case must be considered uncommon. The lesions healed completely after treatment by amphotericin-B.

Use of thermography to predict intestinal viability and survival after ischemic injury: a blind experimental study

Reactive hyperemia is a characteristic of viable ischemic tissue that has been revascularized. In 14 normal dogs, segments of bowel were made ischemic for periods of 2--8 hours. Thermograms and surface temperature measurements of exposed ischemic and nonischemic segments were obtained before and every 5 minutes for 30 minutes after revascularization. Thermograms demonstrated uniform reactive hyperemia throughout the segments ischemic for 2--3 hours; hyperemia with some nonuniform, patchy areas in segments ischemic for 3--7 hours; and no hyperemic response in segments ischemic for 8 hours. All five dogs demonstrating uniform hyperemia survived and the bowels were found to be histologically normal. Four of the six dogs showing hyperemia with some nonuniform areas survived, but all six showed areas of transmural damage with fibrosis and scarring histopathologically. The three dogs with no hyperemic response died of pathologically proved bowel infarction. Our results indicate that thermograms can document the degree and extent of reactive hyperemia. Thermograms, therefore, may be an important aid in assessing bowel viability during surgery.

Computed tomography of experimental acute renal ischemia

The potential role of computed tomography (CT) in the detection of acute renal ischemia was assessed in nine mongrel dogs. Ischemia was produced by inflation of a balloon catheter in the main renal artery, with scans performed before, during, and after a 60-minute period of ischemia. A small but consistent increase in the attenuation value of ischemic renal parenchyma was observed. When intravenous contrast material was given, the ischemic kidney was markedly less enhanced than the contralateral, nonischemic kidney. By using the contralateral kidney for comparison, the ischemic kidney could be identified with or without the use of a contrast agent. Although calculations of mean pixel values were necessary when a contrast agent was not injected, the abnormal kidney could be easily recognized from the CT images themselves when intravenous contrast material was given. Because of the consistency with which the abnormalities were observed, we recommend a clinical trial of CT in suspected acute renal ischemia.

Absolute lung density in experimental canine pulmonary edema

The noninvasive quantification of pulmonary edema could be of importance in patient management. We have developed a portable Compton-scatter densitometer capable of measuring density in the range of 0.1-1 g/cm3 independently of the chest wall. Change in lung density was investigated in 19 dogs with pulmonary edema induced by a combination of raised left atrial pressure and hemodilution. The increase in lung density correlated with the postmortem assessment of lung water (r = 0.862, p less than 0.01) and with hemodynamic indicators of pulmonary edema (r = 0.749, p less than 0.01). Subtracting the intravascular component of lung density did not improve the correlation with postmortem lung water (r = 0.850, p less than 0.01). The measurement of absolute lung density by a Compton-scatter technique may be a potentially useful method of quantifying pulmonary edema.

Computed tomography of splenic subcapsular hematomas: an experimental study in dogs

Following baseline CT scans, splenic subcapsular hematomas were produced in dogs by direct splenic trauma. The CT scans of the spleen were obtained one to two hours before and after administration of IV contrast media and one, two, seven, 14 and 28 days following splenic trauma. Variations in the CT image of the hematomas was correlated with time and alterations in the chemical and histologic nature of the hematoma. Initially, the hematomas were isodense with the normal spleen and identified only following IV contrast administration. The initial number of hematomas identified by CT decreased to about half after seven to 14 days and then remained stable. Analysis of the hematomas revealed an initial increase in hemoglobin which was followed by a decrease. Dry weight increased, then decreased; lipid content decreased over time; and calcium content showed no appreciable change. The CT appearance of splenic subcapsular hematomas is dependent on the age of the hematoma. CT scans done soon after trauma should be performed following administration of intravenous contrast media, while less acute hematomas should be apparent without contrast media. Changes in attenuation values of hematomas appear due to a reduction in hemoglobin content and an increase in water content of the hematoma.

Observation on the metabolism of iopanoyl (Telepaque) glucuronide in dogs treated with antibiotics

The purpose of our investigation was to determine whether iopanoyl glucuronide, the major metabolite of iopanoic acid (Telepaque), undergoes hydrolysis by bacterial beta-glucuronidase in dogs. The conjugated compound was identified and quantitated by elemental analysis, fluorescent excitation analysis, thin-layer chromatography, and high pressure liquid chromatography. The experiments were performed before and after combined antibiotic treatment with neomycin and vancomycin. It was first determined that reabsorption and excretion of sodium iopanoate was only minimally diminished during antibiotic treatment. Known amounts of iopanoyl glucuronide were infused into the small bowel of 4 awake dogs with chronic bile fistula, and bile was collected for 5--8 hours. The excretion of the recirculated conjugated compound was 4--5 times lower during antibiotic treatment. Incubation of ileal fluid with bile containing iopanoyl glucuronide suggested that beta-glucuronidase hydrolyzes the conjugated compound. Hydrolysis was markedly decreased after pretreatment with antibiotics. These findings suggest that the beta-glucuronidase produced by bacteria may be a major mechanism in enterohepatic recirculation of iopanoyl glucuronide. Mechanisms and possible implications are discussed.

Radionuclide imaging of bowel infarction complicating small bowel intussusception in dogs

Technetium-99m (99mTc)-pyrophosphate was investigated for use as an indicator of intestinal infarction in intussuscepted bowel. Irreducible intussusceptions were created in eight adult mongrel dogs. Technetium-99m-pyrophosphate was then injected intravenously 24 and 48 hrs later for external scanning. In six of the dogs, infarction developed in the intussusception, and each demonstrated increased uptake of 99mTc-pyrophosphate on in vivo scintiscans. The two dogs without infarction showed no increase uptake of the radionuclide. Well-counting and specimen scanning confirmed increased radionuclide in the infarcted intussusceptions. These observations suggest that 99mTc-pyrophosphate is a reliable indicator of the vascular compromise that sometimes occurs with intestinal intussusception.

Thermographic assessment of intestinal viability following ischemic damage

Reactive hyperemia has been shown to be a characteristic of viable ischemic tissue that has been revascularized. A segment of small bowel was made ischemic by arterial occlusion and the ischemia maintained for 2 1/2 hrs (ischemic, viable bowel) or 8 hrs (ischemic, nonviable bowel) before circulation was restored. Thermograms and surface temperature measurements of exposed ischemic and non-ischemic bowel segments were obtained before and every five minutes after revascularization. Thermograms of segments revascularized after 2 1/2 hrs of ischemia demonstrated reactive hyperemia and a one to four degree increase in surface temperature compared to normal surrounding bowel. No hyperemic response was seen in bowel segments that were ischemic for 8 hrs. Our results indicate that thermograms can document reactive hyperemia of an exposed ischemic bowel that has been successfully revascularized and may be an important aid in assessing bowel viability during surgery.

The effect of acute pulmonary edema on pulmonary vascular resistance: significance for the interpretation of dilated upper lobe vessels on chest radiographs

Dilation of upper lobe pulmonary vessels is an important radiographic sign of acute, left heart failure. A prominent theory is that perivascular edema causes increased resistance at the lung bases and inverts the normal perfusion gradient such that upper lobe blood flow exceeds lower lobe flow. This theoretical increase in flow is thought to cause dilatation of upper lobe vessels. Previous experimental studies determined indirectly changes in resistance from changes in the perfusion gradient: Results were contradictory. We measured directly the effect of edema on resistance in isolated canine lungs. Resistance increased linearly with edema. The magnitude of increase was small, however, and insufficient to cause inversion of the perfusion gradient. Our data indicate that interstitial pulmonary edema does not cause significant redistribution of blood flow. We suggest that dilated upper lobe vessels are veins acting as pulmonary venous manometers, reflecting elevated left atrial pressure, not increased blood flow.