Quantitative bioimaging of copper in frozen liver specimens from cats using laser ablation-inductively coupled plasma-mass spectrometry

OBJECTIVES

The aim of this study was to assess laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) as a tool for measuring concentrations and determining accumulation of copper in frozen liver specimens from cats.

METHODS

Six frozen liver specimens were evaluated by qualitative copper staining and quantitative flame atomic absorption spectroscopy. Tissue specimens were cryo-sectioned and quantitative bioimaging of copper was performed using LA-ICP-MS. Results were compared with those obtained using conventional methods.

RESULTS

Of the six specimens, only one showed positive staining for copper with rhodanine. Using flame atomic absorption spectroscopy (FAAS), one specimen showed a deficient copper level (<100 µg/g dry weight), two specimens had copper within the reference interval (RI; 150-180 µg/g) and three specimens had copper concentrations above the RI. Bioimaging from LA-ICP-MS showed inhomogeneous distribution of hepatic copper. The areas with dense copper accumulation were represented as hotspots in the liver specimens. Hepatic copper quantification by LA-ICP-MS correlated well with copper quantified by FAAS (r = 0.96, P = 0.002).

CONCLUSIONS AND RELEVANCE

Our findings suggest that quantitative bioimaging by LA-ICP-MS could be used to demonstrate the distribution and concentration of copper in frozen liver specimens from cats. The distribution of copper in these specimens was inhomogeneous with dense accumulation represented as hotspots on tissue sections. A positive correlation of hepatic copper concentrations determined by LA-ICP-MS and FAAS was found. Further studies to establish an RI for hepatic copper using this technique and to further determine its clinical utility are warranted.

Assessment of the intracellular distribution of copper in liver specimens from cats

The intracellular distribution of copper in the liver has been investigated in dogs and humans. However, this has not been reported in cats. This study aimed to assess the intracellular copper distribution in liver specimens from cats with a range of hepatic copper concentrations. Twenty-nine frozen liver specimens from cats were included. Each liver specimen was divided into two pieces for overall copper quantification and tissue fractionation. The copper concentrations in liver specimens and liver fractions were measured by flame atomic absorption spectroscopy. Five specimens had copper concentrations < 100 μg/g dry weight, eight had copper concentrations between 100 and 180 μg/g, 14 had copper concentrations between 181 and 700 μg/g, and two had copper concentrations >700 μg/g. Only one specimen had positive copper staining. Regardless of the overall concentrations, copper was mostly found in the cytosolic fraction followed by the nuclear, large granule, and microsomal fractions. Our findings indicate that similarly to other species, intracellular copper is predominantly found in the cytosolic and nuclear fractions in cats. The distribution in cats with copper-loaded conditions, such as primary copper hepatopathy, was not assessed but warrants evaluation.

Medical conditions associated with gastroduodenal ulceration or erosion in 168 dogs: 2008-2018

Background

Many medical conditions are thought to cause gastroduodenal ulceration or erosion (GUE) in dogs. However, evidence for the association between many of these conditions and GUE in dogs is lacking.

Objective

To identify medical conditions associated with GUE in dogs.

Animals

One hundred and sixty‐eight dogs with GUE and 168 randomly selected control dogs without evidence of GUE identified on necropsy between January 2008 and September 2018.

Methods

Patient signalment, blood urea nitrogen (BUN) and serum creatinine concentrations, recently administered ulcerogenic drugs, as well as necropsy findings were recorded. The association between these findings and presence of GUE was assessed by univariable and multivariable analysis.

Results

In the final multivariable model, the following factors were associated with GUE: Nonsteroidal anti‐inflammatory drug (NSAID) administration (odds ratio [OR], 6.3; 95% confidence interval [CI], 2.3‐17.4; P = .0004), glucocorticoid administration (OR, 3.0; 95% CI, 1.5‐5.9; P = .001), gastrointestinal neoplasia (OR, 13.5; 95% CI, 1.7‐108.0; P = .01) and gastrointestinal mechanical disease (foreign bodies, gastric dilatation, and volvulus; OR, 4.8; 95% CI, 1.2‐19.7; P = .03). Additionally, working dog breeds were predisposed to GUE compared to mixed breed dogs (OR, 2.8; 95% CI, 1.1‐7.4; P = .04). Insufficient clinical data was available to either support or refute a role of other putative risk factors evaluated.

Conclusion and Clinical Importance

Administration of NSAID or glucocorticoid and gastrointestinal neoplasia or mechanical disease were associated with GUE in dogs. The potential predisposition of working breed dogs for GUE requires further investigation.

Assessment of copper accumulation in archived liver specimens from cats

OBJECTIVES

The aim of this study was to assess hepatic copper concentrations and zonal distribution in cat liver specimens.

METHODS

For this study, 121 archived, formalin-fixed, paraffin-embedded liver specimens from cats were used. Tissue sections were stained for copper with rhodanine and scored from 0 (no copper accumulation) to 5 (panlobular copper accumulation). The tissue specimens were then deparaffinized and hepatic copper concentrations were measured using flame atomic absorption spectroscopy.

RESULTS

Tissue samples were categorized into four groups based on histopathologic findings: (1) no significant histopathologic hepatic changes (n = 66); (2) hepatic steatosis (n = 18); (3) inflammatory or infectious disease (n = 24); and (4) neoplasia (n = 13). Of the 121 specimens, 13 (11%) stained positive for copper, with three having a score ⩾3. Thirty-seven specimens (31%) had copper concentrations above the reference interval ([RI] <180 µg/g dry weight liver). Copper concentrations in cats with hepatic inflammatory or infectious disease were significantly higher than cats with hepatic steatosis (P = 0.03). Copper-staining score and concentration were positively correlated (r_s = 0.46, P <0.001).

CONCLUSIONS AND RELEVANCE

Despite the fact that 31% of specimens had copper concentrations above the RI, only 11% showed positive copper staining and only 2.5% had a score ⩾3. Our findings suggest that hepatic copper concentrations greater than the upper limit of the RI are relatively common in cats. Further studies to determine the factors that influence hepatic copper staining in cats and to establish contemporary RIs for hepatic copper in healthy cats are warranted.

Effects of osteoarthritis on radiographic measures of laxity and congruence in hip joints of Labrador Retrievers

OBJECTIVE- To determine effects of hip joint osteoarthritis on radiographic measures of hip joint laxity and congruence. DESIGN- Longitudinal study. ANIMALS- 40 Labrador Retrievers. PROCEDURES- Dogs were assigned to 2 groups based on radiographic evidence of osteoarthritis. Dogs in the osteoarthritis group were free of osteoarthritis at initial radiographic evaluation (t(1)) and developed osteoarthritis by a subsequent radiographic evaluation (t(2)). Dogs in the nonosteoarthritis group had no radiographic osteoarthritis at either evaluation. Hip joint laxity was quantified by use of the distraction index (DI) from a distraction radiographic view and use of the Norberg angle (NA) from a ventrodorsal hip-extended radiographic view. The compression index (CI) from a compression radiographic view was used as a measure of joint congruence (concentricity). RESULTS- Hip joint laxity (NA or DI) did not change over time in the nonosteoarthritis group. Mean hip joint laxity (NA and DI) for the osteoarthritis group was greater at t(1) than for the nonosteoarthritis group. With the onset of osteoarthritis, mean NA decreased significantly and mean CI increased significantly, but mean DI remained unchanged. CONCLUSIONS AND CLINICAL RELEVANCE- No radiographic evidence for compensatory hip joint tightening associated with osteoarthritis was detected. Hip-extended radiography revealed that hip joints got looser with osteoarthritis and NA decreased. Hip joint laxity (DI) on distraction radiographs was unchanged by the onset of osteoarthritis and remained constant in the osteoarthritis and nonosteoarthritis groups at both evaluations. However, the CI increased with osteoarthritis, as reflected in nonzero indices (incongruence). The CI may be a valid marker for early hip joint osteoarthritis.

Comparison of the clinical performance of the Acuvue disposable contact lens and CSI lens in patients with giant papillary conjunctivitis

Anecdotal reports have suggested that the use of disposable contact lenses is an effective treatment for giant papillary conjunctivitis. In a prospective randomized double-masked study, we compared the clinical performance of the Acuvue (Vistakon, Jacksonville, Florida) disposable contact lens to the traditional daily-wear lens of choice, CSI (Pilkington Barnes Hind, Sunnyvale, California), in 37 patients with previously diagnosed giant papillary conjunctivitis who were examined at one-month intervals for six months. A survey questionnaire for grading symptoms disclosed significant improvement in itching, discharge, and blurred vision in both groups early in the study. Evaluation of patient preference showed that the CSI lens was strongly preferred with regard to lens handling (76% vs 8%). In contrast, the Acuvue lens was strongly preferred with regard to lens comfort (62% vs 11%). For the variable of overall lens preference, there was no significant difference between the two lenses (CSI, 43% and Acuvue, 41%). Multiple regression analysis disclosed that both lens comfort (P < .002) and lens handling (P = .05) contributed significantly to the choices made regarding the dependent variable of overall lens preference. Lens comfort (beta = .71) was observed to be approximately 50% more powerful than lens handling (beta = .48). There was no significant difference in the rate or cost of torn lenses between groups, suggesting that the Acuvue lens can withstand the physical manipulation associated with daily-wear use for up to one month. The results of this study suggest that the use of disposable contact lenses for the treatment of giant papillary conjunctivitis is at least as effective as the traditional daily-wear lens of choice.

Argon laser fenestration of a Softperm contact lens

Contact lens fenestration can increase tear exchange. We describe a case in which a patient with 15 D of against-the-rule astigmatism was fit with a Softperm contact lens but was unable to wear it for more than 1 hour because of corneal edema. After fenestrating the Softperm lens with an argon laser the patient was able to wear her lens for 10 hours without signs of corneal decompensation.

Anion exchanger is present in both luminal and basolateral renal membranes

Binding of the anion-exchange inhibitor 3H2-labeled 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS) to highly purified luminal and basolateral beef kidney tubular membranes was characterized. Specific binding of [3H2]DIDS is present in both luminal and basolateral membranes. Scatchard analysis revealed a Kd for [3H2]DIDS of 5.5 microM and 19.3 microM and a maximal number of binding sites of 10.9 nmol and 31.7 nmol DIDS/mg protein in basolateral and luminal membranes, respectively. To assess the role of this putative anion exchanger on transport we measured 35SO4 uptake by luminal and basolateral membranes. In both luminal and basolateral membranes sulfate uptake was significantly greater in the presence of an outward-directed Cl gradient, OH gradient or HCO3 gradient than in the absence of these gradients. There was an early anion-dependent sulfate uptake of five to ten times the equilibrium uptake at 60 min. The sulfate taken in could be released by lysis of the vesicles indicating true uptake and not binding of sulfate. No significant difference in SO4 uptake was found in the presence and in the absence of valinomycin, indicating that the anion exchanger is electroneutral. The anion-dependent sulfate uptake was completely inhibited by either DIDS or furosemide in both luminal and basolateral membranes. Dixon analysis of HCO3-dependent SO4 uptake by luminal membranes in the presence of different concentrations of DIDS revealed a Ki for DIDS of 20 microM. The similar values of the Kd for [3H2]DIDS binding and the Ki for DIDS inhibition of SO4 uptake might suggest an association between DIDS binding and the inhibition of SO4 transport. In addition, an inward-directed Na gradient stimulated sulfate uptake in luminal but not in basolateral membranes. The Na-dependent sulfate uptake in luminal membranes was also inhibited by DIDS. We conclude that, in addition to the well-known Na-dependent sulfate uptake in luminal membranes, there exists an anion exchanger in both basolateral and luminal membranes capable of sulfate transport.

Adipose tissue mobilization is unaffected by obesifying hypothalamic knife cuts

Unilateral electrolytic lesions of the medial hypothalamus have previously been reported to spare starvation-induced lipid mobilization from the ipsilateral retroperitoneal fat pad. This suggests that deficient lipid mobilization contributes to the enhanced lipid deposition which results when such lesions are bilateral. In contrast, unilateral parasagittal hypothalamic knife cuts, which also obesify when bilateral, failed to prevent starvation-induced ipsilateral lipid mobilization. This finding indicates that impairment of neurally mediated lipid mobilization is probably neither a necessary nor a sufficient feature of hypothalamic obesity.

Fanconi's syndrome associated with carburetor fluid intoxication

A patient who ingested carburetor fluid developed methanol intoxication followed by hypouricemia, hypophosphatemia, glycosuria, and hyperchloremic metabolic acidosis. Renal clearances of phosphate, uric acid, glucose, and bicarbonate were found to be elevated indicating the presence of Fanconi's syndrome. The authors postulate that the Fanconi's syndrome observed in our patient was the result of the organic solvents present in the mixture.

The Lee Obesity Index vindicated?

Correlations are reported for rats between the Lee Obesity Index and percent body fat. At weaning, rats were divided into 4 groups; supermarket diet and ovariectomy, supermarket diet and sham surgery. Lab Chow pellets and ovariectomy, and Lab Chow pellets and sham surgery. Four other groups received the treatments as adults. Eighteen and fifteen weeks later, respectively, the rats were measured for Obesity Index and were sacrificed for carcass analysis. The Obesity Index correlated well with percent body fat for animals made obese by diet; but it was not generally reliable for ovariectomized rats or for pellet fed sham operated controls. The Percent body fat also correlated well with body weight and with a simple weight/length ratio for rats made obese by diet. Thus, while the Obesity Index can reliably predict percent body fat, it may be no better at doing this than are some simpler measures.

Evidence for vagal involvement in the eating elicited by adrenergic stimulation of the paraventricular nucleus

We examined the role of the vagus nerves in mediating the eating and preprandial drinking seen after injection of norepinephrine (NE) into the region of the paraventricular hypothalamic nucleus of satiated rats. Complete subdiaphragmatic vagotomy (confirmed by gastric secretion tests) abolished the NE-elicited eating response, whether the diet used was lab chow, milk, or a milk-chow misture, and attenuated, by 38%, the NE-elicited drinking response. These effects occurred independently of changes in body weight or daily food intake imposed by vagal surgery. The vagotomized rats retained the capacity to rapidly increase eating in response to food deprivation or insulin injection challenges, indicating that the effect of vagotomy on NE-induced eating was not due to some non-specific impairment. Efferent vagal blockade of intact rats with systemic injections of atropine methyl nitrate (0.4 mg/kg) prior to central NE infusions yielded similar results. Finally-selective section of the coeliac branch of the vagus produced a 49% reduction of NE, elicited eating, as compared with a 29% reduction in water intake, while selective section of the gastric plus hepatic vagal branches, leaving only the coeliac branch intact, did not significantly affect either ingestive response. Both of these selectively vagotomized groups displayed an unimpaired capacity to increase food intake in response to systemic insulin injections. These results suggest participation of efferent vagal mechanisms in the adrenergic feeding, and, to a lesser extent, drinking phenomena and are consistent with a particular role for some function under coeliac vagal control (perhaps insulin secretion) in modulating the effects of NE on feeding behavior.

Horizontal stereotaxic atlas of the albino rat brain

An atlas of the albino rat brain was prepared in the horizontal plane, extending from the olfactory bulbs through the hind brain. It was drawn to the scale of König and Klippel's rat brain atlas so as to be used in conjunction with their atlas. Corresponding histological sections were also prepared.

Circadian rhythms in vasopressin deficient rats

Circadian rhythms in wheel running and drinking behavior were investigated using heterozygous an homozygous (diabetes insipidus) female Brattleboro rats Despite the lack of vasopressin in the suprachiasmatic nuclei of the diabetic rats, they showed coherent rhythms, both in cyclic light and in constant light. However, the periods of the free-running rhythms were longer for the diabetic rats, they were less active, and, of course, were severely polydipsic. Replacement treatment with systemic infusions of vasopressin reversed the polydipsia but did not affect the other measures.

Hypothalamic knife cut obesity in hyper or hypothyroid rats

Recent evidence indicates that the paraventricular nucleus of the hypothalamus (PVN) contains both neurons that produce thyrotropic releasing hormone (TRH) and neurons that are destroyed or disconnected by the knife cuts that produce hypothalamic hyperphagia and obesity. This, and other evidence, suggested linkage between thyroid regulation and appetite control. As predicted, hyperthyroidism potentiated and hypothyroidism tempered the weight gains of knife cut rats. However, these effects were due entirely to increased and decreased, respectively, linear growth, not to differences in the degree of obesity. Enhanced linear growth and elevated growth hormone levels are a minor component of the enhanced weight gain of hypothalamically knife cut rats. Most of the weight gain is due to fat deposition. Only the enhanced linear growth and growth hormone aspect appear to possibly be mediated via the thyroid. In addition, obesifying knife cuts did not reduce goiterogenesis in PTU treated rats, as would be expected if the elaboration of TRH were blocked by obesifying knife cuts. Thus, neither TRH nor thyroxine is involved in the etiology of hypothalamic obesity.

Vagal mediation of hypothalamic obesity but not of supermarket dietary obesity

In two independent experiments, complete subdiaphragmatic vagotomy did not prevent the development of the obesity that results from the addition of highly palatable foods to the diet of rats. The vagotomized animals exhibited only a 1-day delay in the onset of overeating, and this only when first exposed to the tasty diet. In independent tests of the functional completeness of the vagotomies, the vagotomized animals failed to overeat or gain excessive weight on a standard laboratory diet following bilaterally parasagittal hypothalamic knife cuts. Thus, hypothalamic knife-cut obesity requires the integrity of the vagus for its full expression, whereas dietary obesity does not.

Depriving or pair feeding intact controls induces some persisting regulatory deficits similar to those of the recovered lateral rat

To determine the extent to which acute starvation might contribute to the chronic deficits in regulatory feeding, drinking, and body weight maintenance characteristic of rats with lateral hypothalamic brain lesions, neurologically intact rats were pair-fed (including forced feedings) and pair-watered for 2-4 wk with rats rendered transiently aphagic and adipsic by hypothalamic knife cuts. When the pair-fed rats were subsequently allowed to free-feed, their body weights remained suppressed. In addition, the pair-fed rats failed to eat in response to glucoprivation induced by insulin or 2-deoxy-D-glucose. The pair-fed rat drank less than nondeprived controls, but more than rats with knife cuts, when administered osmotic or volemic challenges to thirst. Other aspects of the recovered lateral syndrome were absent. In a second experiment, intact rats that had recovered from varying durations of semistarvation with or without subsequent forced feedings were tested for regulatory impairments. Deficits in chronic body weight maintenance were found in rats that had been starved and subsequently force-fed. Diminished responses to glucoregulatory challenges were seen in rats that had been starved but not forced-fed as well as in those that had been force-fed but not starved. This impaired eating in response to glucoregulatory challenges abated with repeated testing. Thus, both the acute failure of ingestive behaviors and therapeutic forced feedings can contribute to the impired regulatory eating and driniing that follow recovery from certain types of brain damage.

Non-effect of Massachusetts cement kiln dust upon the food intake, body weight, or activity of female rats

The addition of Georgia cement kiln dust to the diet of cattle or weanling male rats has been reported to increase body weight and feed efficiency. We attempted to replicate these effects by adding kiln dust to the Purina laboratory chow of adult female rats. Massachusetts cement kiln dust caused no significant change in food intake, weight gain, or activity. The kiln dust effect appears, therefore to depend upon (a) ingredients peculiar to Georgia kiln dust, (b) age (juveniles vs. adults), (c) sex and/or (d) deficiencies of the control diet.

Axon-sparing brain lesioning technique: the use of monosodium-L-glutamate and other amino acids

Infusions of monosodium-L-glutamate into the rostral hypothalamus, believed to contain neurons mediating satiety, produced persistent hyperphagia and obesity, thus suggesting that a brain lesion had been produced. Similar infusions into the caudal hypothalamus, believed to contain unmyelinated axons of passage that mediate satiety, failed to alter food intake or body weight. Histological examination of the affected tissue confirmed the behavioral evidence that suggests that this technique spares axons but destroys cell bodies. Infusion of several other amino acids also damaged neurons while sparing axons of passage.

Two satiety systems revealed by hypothalamic knife cuts in hypophysectomized rats

When pituitaries are intact, hypothalamic knife cuts produce obesity in adult rats but not in weanlings. Knife cut weaning females do not usually begin to become obese until after they are 7 weeks old. When pituitaries are removed, symmetrical or asymmetrical knife cuts produce obesity promptly in both adults and weanlings. Obesity indices that correct for stunted linear growth reveal that in adults the degree of obesity is independent of the presence or absence of the pituitary. Based on these findings we speculate that there may be two appetite regulating systems, a juvenile one involving the pituitary, and an adult one involving the hypothalamus.

Glucoprivic (2DG) eating in rats despite knife cut induced hyperphagia

Two weeks after parasagittal hypothalamic knife cuts, baseline eating was elevated and 300 mg/kg 2 deoxy-D-glucose (2DG) did not further stimulate food intake. Five weeks postoperatively the food intake baseline had fallen and an eating response to 300 mg/kg 2DG was now seen (p less than 0.005). In this delayed (static) phase intake was also stimulated by 150 mg/kg 2DG (p less than 0.005). 600 mg/kg did not stimulate intake in the lesioned rats at any time, although sham-operated rats always responded positively to this high dose. In conclusion, the neural substrate damaged in hypothalamic hyperphagic rats does not appear to mediate eating in response to glucopribation. The eating response is masked by high baseline intake in the dynamic phase, but reappears in the static phase.

Hypothalamic hyperphagia despite imposed diurnal or nocturnal feeding and drinking rhythms

Rats normally do most of their eating at night. When ad lib fed rats are made hyperphagic with lesions or parasagittal hypothalamic knife cuts the increases in eating occur primarily during the day. This suggests that a disruption of circadian rhythms may mediate the overeating. However, when knife cut rats were food and water deprived all day excessive eating occurred at night. Similarly, when they were deprived all night overeating occurred during the day. Under both conditions od deprivation the food intakes and rapid weight gains of the ad lib fed knife cut group were defended. It was concluded that: (1) in hypothalamic hyperphagia either the excessive food intake or the excessive weight gain is defended when food and water are available only half of each day, and (2) disruption of nocturnal feeding and drinking rhythms is not the cause of hypothalamic hyperhagia.

Delayed hyperphagia and increased body length after hypothalamic knife cuts in weanling rats

Four-week-old female rats received parasagittal hypothalamic knife cuts. Polydipsia began right surgery, but hyperphagia, obesity, and excessive nose-anal length did not begin until after the rats were 7-8 wk. old. The delayed onset appears to await some maturational event that is required for the expression of hypothalamic obesity. It appears likely that puberty is the critical maturational event.

Hypothalamic obesity: the myth of the ventromedial nucleus

Lesions restricted to the ventromedial nucleus of the hypothalamus were neither necessary nor sufficient for, and did not contribute to, the production of hypothalamic obesity. Hypothalamic lesions and knife cuts that do produce obesity damage the nearby ventral noradrenergic bundle or its terminals.

Tongue Cooling during Drinking: A Regulator of Water Intake in Rats

Rats that had been deprived of water for 23(1/2) hours were presented with water for 30 minutes per day. As the temperature of the water was increased from 12 degrees to 36 degrees C (body temperature), the total water intake for 30 minutes increased 71 percent. Tongue cooling during drinking appears to suppress drinking in anticipation of extracellular hydration.