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Biomedical subjects

S L Lovering

Publications and source records attributed to S L Lovering.

12 recordsLinked to original sources
PubMed2001

Quality of tissue specimens obtained endoscopically from the duodenum of dogs and cats.

OBJECTIVE: To evaluate quality of duodenal tissue specimens obtained endoscopically from dogs and cats and submitted to 1 of 2 diagnostic laboratories for evaluation. DESIGN: Case series. SAMPLE POPULATION: Slides from 50 consecutive canine and 50 consecutive feline endoscopically obtained duodenal tissue specimens submitted to laboratory 1 and 49 consecutive canine and 46 consecutive feline specimens submitted to laboratory 2. PROCEDURE: Slides were examined independently by 3 investigators, and each tissue piece on each slide was classified as clearly inadequate, questionable, or clearly adequate on the basis of 4 criteria. An overall score was then assigned to the slide. RESULTS: Slides from laboratory 1 were more likely to be scored as clearly adequate and less likely to be scored as clearly inadequate than slides from laboratory 2. Clearly adequate slides from laboratory 1 had a higher number of clearly adequate pieces of tissue than did clearly adequate slides from laboratory 2. Slides scored as clearly adequate had a higher number of individual tissue pieces than did slides scored as clearly inadequate. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the quality of endoscopically obtained duodenal tissue specimens submitted to laboratories can vary, possibly because of differences in experience of individuals collecting biopsy specimens. Results suggest that at least 8 individual tissue pieces should be submitted when performing endoscopic biopsy of the duodenum in dogs and cats.

Animals↗
PubMed1999

Ultrastructural localization of unique neurosecretory granules in the corpora cardiaca of the stable fly, Stomoxys calcitrans, and the tsetse fly, Glossina morsitans.

Ultrastructural analysis of the corpora cardiaca of the stable fly, Stomoxys calcitrans, and the tsetse fly, Glossina morsitans, revealed the presence of elementary neurosecretory granules (ENG) unique to the intrinsic neurosecretory cells (INC) of these species. In addition to electron-dense spheres, the INC of the corpus species. In addition to electron-dense spheres, the INC of the corpus cardiacum of the stable fly contain electrondense angular granules, either square or rectangular in shape, while the INC of the tsetse fly contain electron-dense spindle-shaped ENG. The distinctive granules of these INC can be traced within nerves to their sites of storage and release, eliminating the need for labeling with artificial probes. Although the INC of the corpus cardiacum of most species have been found to be fuchsinophilic, neither the INC of the stable fly nor the tsetse fly are aldehyde-fuchsinophilic. These peptigenic cells offer neuroendocrinologists a unique opportunity to study the physiology and biochemistry of neurosecretory cells.

Animals↗
PubMed1992

Mammary adenocarcinoma in four mares.

Mammary gland adenocarcinoma in 4 horses was characterized by firm swelling of the gland and serosanguineous discharge from the teat orifice. Two of the mares had ulcerative lesions of the mammary gland. Palpation of the affected gland typically elicited signs of pain. Diagnosis was assisted by cytologic evaluation of the fluid discharge, but definitive diagnosis was based on histologic examination. Treatment included mastectomy and lymphadenectomy.

Adenocarcinoma↗
PubMed1991

Behavioral and histopathologic effects following intrathecal administration of butorphanol, sufentanil, and nalbuphine in sheep.

A large number of opioids and nonopioids have been administered epidurally and intrathecally in the hope of providing segmental analgesia without serious adverse effects. However, neurotoxicity data are generally unavailable for many of these drugs. The present study evaluated the behavioral, motor, electroencephalographic, and histopathologic changes following intrathecal injection of large and small doses of butorphanol, sufentanil, and nalbuphine in sheep. Thirty-two sheep (20-32 kg) were anesthetized and catheters placed intrathecally after hemilaminectomy. The large doses of butorphanol, sufentanil and nalbuphine were 0.375 mg/kg (4.4-5.2 ml), 7.5 micrograms/kg (3.6-4.8 ml) and 0.75 mg/kg (1.5-2.4 ml), and the small doses were 0.075 mg/kg (0.9-1.1 ml), 1.5 micrograms/kg (0.7-0.9 ml) and 0.15 mg/kg (0.38-0.5 ml), respectively. The opioids were administered intrathecally every 6 h for 3 days and the above-mentioned parameters studied. Five sheep received intrathecal saline (1.1 or 5.2 ml) and served as controls. Histopathologic changes were evaluated by a neuropathologist blinded to the study protocol. Irrespective of dose, intrathecal injection of butorphanol was associated with severe behavioral responses such as agitation, rigidity, vocalization, and restlessness, as well as prolonged or irreversible hindlimb paralysis. Electroencephalography showed increased cortical activity or seizure activity. One sheep died because of severe respiratory depression that did not respond to naloxone. Spinal cord histologic changes consisted of suppurative meningitis and myelitis as well as neuronal changes such as spongiosis and chromatolysis. Large doses of intrathecal sufentanil were associated with similar though somewhat less severe responses. The behavioral and motor changes following the small dose of intrathecal sufentanil were of mild to moderate nature. Following intrathecal nalbuphine, the above-mentioned changes were similar to those seen in control animals. We conclude that butorphanol in doses of 0.075 and 0.375 mg/kg intrathecally and sufentanil 7.5 micrograms/kg intrathecally are neurotoxic in sheep.

Animals↗
PubMed1984

A chick model for impaired renal function.

To evaluate some of the metabolic consequences of impaired renal function (IRF) in the chick, a surgical method to induce IRF was developed that involves the destruction of approximately 85% of the renal mass by ureteral ligation. It is relatively simple with minimal time and labor required, produces low mortality, requires little specialized postoperative care, and is readily reproducible. Three-week-old control, sham-operated, and IRF chicks were bled by cardiac puncture and biochemical measurements were made on serum samples. Serum uric acid concentration was the most sensitive indicator of IRF, with mean levels in the IRF chicks being increased above control and sham-operated chicks 3.3-, 2.7-, 2.0-, and 1.2-fold at 1, 3, 7, and 14 days, respectively. The gradual decline in uric acid levels is most likely related to the functional recovery and hypertrophy of the remaining renal mass. The IRF chick model will be useful to provide information on renal aspects of the toxicity, distribution, metabolism, and elimination of nephrotoxic agents.

Animals↗
PubMed1984

The influence of multiple liver biopsies on hematologic and serum biochemical values of sheep.

A rapid, simple liver biopsy technique for sheep was developed to obtain in situ liver samples for evaluation of histological tissue, enzyme assay, and ultrastructural changes that might occur during toxicological testing. The study was designed because repeated biopsies in the same individual could induce bias in hematologic, histological or serum biochemical parameters caused by the trauma of the biopsy procedure. In Experiment I, sheep were divided into a biopsied group (B), sham-operated group (SO), and a nonsurgical, untreated control group (C). Three liver biopsy samples per week were removed from each subject in Group B for five weeks. Biweekly blood samples were drawn for evaluation of hematologic and serum biochemical parameters. In Experiment II, Groups B and SO were dosed with CCl4 in order to validate the applicability of the biopsy procedure. Weekly biopsies were continued in Group B. Biweekly blood samples were evaluated for any hematologic or serum biochemical variations. Significant elevations of enzyme activities confirmed CCl4 hepatotoxicity in treated groups (B and SO) versus C group. Histological lesions in biopsy samples correlated closely with serum biochemical data in treated groups. It was concluded that the serial liver biopsy procedure causes negligible alterations in the hematologic, histological or serum biochemical parameters measured; is simple and rapid to perform, and provides a method for possible early detection of liver disease.

Animals↗
PubMed1983

Toxicity of 3,3',4,4'- and 2,2',5,5'-tetrabromobiphenyl: correlation of activity with aryl hydrocarbon hydroxylase induction and lack of protection by antioxidants.

3,3',4,4'-Tetrabromobiphenyl is a minor component of commercial polybrominated biphenyl (PBB) mixture fireMaster BP-6 and is a potent inducer of aryl hydrocarbon hydroxylase (AHH). A single ip dose of 3,3',4,4'-tetrabromobiphenyl (150 mumol/kg) caused significant reduction in the growth rate in the immature male Wistar rat, as well as pale enlarged livers and marked reduction in thymus size. Under light microscopy, hepatocytes were enlarged and vacuolated. The vacuoles, which were most prominent in the midzonal region of the lobule, corresponded to fat droplets in oil-red-O-stained sections. The thymus, especially the cortex, was markedly depleted of lymphocytes. Neither the reduced growth, altered organ weights nor the histopathology was reversed for the duration of the study by the coadministration of the antioxidants butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT), or vitamin E. Vitamin E did, however counter the negative effect of 3,3',4,4'-tetrabromobiphenyl on growth during the first 5 d of the study. 2,2',5,5'-Tetrabromobiphenyl, also a minor component of fireMaster BP-6, is a weak phenobarbital-type inducer of cytochrome P-450. When administered at the same dose, 2,2',5,5'-tetrabromobiphenyl did not elicit any observed toxic effects. These data confirm the correlation between AHH induction and toxicity for these PBBs and suggest that 3,3',4,4'-tetrabromobiphenyl may significantly contribute to the toxicity of fireMaster BP-6. Although there is evidence that polychlorinated biphenyls, and perhaps 2,3,7,8-tetrachlorodibenzo-p-dioxin, exert certain toxic effects via a lipid peroxidation mechanism, the toxic changes measured during this study were not reversed by the administration of the antioxidants.

Animals↗
PubMed1983

Phototoxic effect of Thamnosma texana (Dutchman's breeches) in sheep.

Oral exposure of sheep to the airdried, aerial portions of Thamnosma texana (Dutchman's breeches) resulted in severe photosensitization. Sheep fed the plant at 9 or 12 g/kg of body weight/day and held in direct sunlight exhibited signs of phototoxicosis within 24 to 48 hours. The clinical signs manifested were increased body temperature; photophobia; edema of the muzzle, ears, and vulva; keratoconjunctivitis with edema of the cornea; and exudative dermatitis of the skin of the ears, muzzle, and vulva. Lesser dosages of the plant produced similar effects after several days, except that corneal edema and opacity were not seen. Histopathologic studies indicated no hepatic lesions, consistent with primary photosensitization. The photosensitizing effects of T texana can be attributed to the presence of photosensitizing linear furocoumarins (psoralens) in the plant.

Animals↗
PubMed1982

Cytoplasmic bridges between mammalian red blood cells: an early indication of kidney dysfunction.

Scanning electron microscopy, correlated with hematological and clinical biochemical observations demonstrated that cytoplasmic bridges develop between the erythrocytes of sheep in which varying degrees of acute renal dysfunction has been produced by treatment with a toxin (uranyl nitrate) or by surgical ligation of a renal artery or ureter. The presence of cytoplasmic bridges between red blood cells was noted prior to clinical indication of renal dysfunction. Thus, these preliminary studies indicate that the development of cytoplasmic bridges between erythrocytes may be a diagnostic clue for early detection of renal dysfunction.

Animals↗
PubMed1982

Acute toxicity of tri-ortho-cresyl phosphate in sheep and swine.

Tri-ortho-cresyl phosphate (TOCP) was given orally or by subcutaneous (SC) injection to sheep and swine. Sheep given oral doses of 100, 200, or 400 mg of TOCP/kg of body weight developed an acute intoxication characterized by diarrhea dehydration, metabolic acidosis, and death within 6 days. Daily SC injections of TOCP in sheep caused either death or delayed neurotoxicosis depending upon the dosage. Increase of aspartate aminotransferase activity approximately 24 hours before the animal died and histopathologic changes confirmed that liver injury had occurred. Swine dosed with 100 to 1,600 mg of TOCP/kg had minimal signs of acute toxicosis, but developed severe delayed neurotoxicosis in approximately 15 days. Those given a 800 mg/kg dose by the oral route or SC injection had severely decreased serum acetylcholinesterase activity. In the swine which were euthanatized at 7 days after treatment, histopathologic examinations revealed no lesions (although the nervous system was not examined, because clinical neurologic signs were normal).

Administration, Oral↗
PubMed1980

Serum complement and blood platelet adhesiveness in acute canine ehrlichiosis.

Three dogs inoculated with Ehrlichia canis served as infected controls (group I), 3 dogs treated with cobra venom factor (CVF) after inoculation with E canis were the principals (group II), 3 noninfected dogs were the noninfected controls (group III), and 1 noninfected dog given CVF was the noninfected, decomplemented control (group IV). Thrombocytopenia occurred in all E. canis-inoculated dogs (groups I and II) within 3 weeks after they were inoculated. However, the severity of the thrombocytopenia was moderated in the group II dogs (decomplemented E canis-inoculated). Hypocomplementemia occurred in the CVF-treated dogs (groups II and IV) immediately and persisted for up to 5 days after administration of CVF. Hypocomplementamia also occurred in all E canis-infected dogs (groups I and II) during the period of maximal thrombocytopenia. The mean platelet retention was significantly decreased in all E canis-inoculated dogs and in the CVF-control dog (groups I, II, and IV). There was no correlation between platelet retention and the number of platelets in group III (nontreated, noninoculated) controls. The correlation between the decrease in platelet retention and the number of platelets was significant in the complement-intact infected dogs, yet was not significant in the decomplemented infected dogs. Data indicated that complement consumption occurred in acute canine ehrlichiosis and coincided, to a degree, with the development of thrombocytopenia. Decomplementation of inoculated dogs moderated the severity of the thrombocytopenia. Platelet function is also altered in acute stages of the disease.

Animals↗