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Biomedical subjects

L H Arp

Publications and source records attributed to L H Arp.

At least 37 records · Page 2Linked to original sources
PubMed1987

Ultrastructural pathology of Bordetella avium infection in turkeys.

One-day-old turkeys were infected intranasally with Bordetella avium, and tracheas were examined by scanning and transmission electron microscopy at 1 to 5 weeks post-inoculation (PI). The predominant ultrastructural lesions were progressive loss of ciliated epithelium with replacement by nonciliated cells, bacterial colonization of ciliated cells, membrane-bound crystalline inclusions in cytoplasma of epithelial cells, depletion of mucous granules, and distortion of tracheal rings and the mucosal surface. Tracheal surface exudates consisted of mucus, necrotic cells, heterophils, and fibrin. Ciliated cells were replaced by immature cuboidal cells characterized by abundant rough endoplasmic reticulum with small numbers of electron-dense mucous granules in the apical cytoplasm. Bacterial surfaces were rough and contained numerous pleomorphic, knob-like structures, 20-50 nm in diameter. Other changes included enlarged mucosal gland openings, cell extrusion marks, pleomorphic microvilli, and cells with small numbers of short cilia.

Animals↗
PubMed1987

Influence of Bordetella avium infection on association of Escherichia coli with turkey trachea.

Four-week-old Bordetella avium-infected and B avium-free turkeys were inoculated intratracheally with a suspension of fimbriated or nonfimbriated Escherichia coli. Numbers of E coli associated with tracheal sections were determined at postinoculation hour (PIH) 1 or 6. Significantly (P less than 0.05) greater numbers of E coli were isolated from the tracheas of B avium-infected turkeys compared with numbers in B avium-free turkeys. In B avium-free turkeys, tracheal associated E coli were 90% less at PIH 6 compared with that at PIH 1. However, in B avium-infected turkeys, numbers of E coli were not affected by postinoculation time. Seemingly, B avium-infected turkeys had reduced capacity to clear E coli from the trachea.

Animals↗
PubMed1987

Effects of Bordetella avium infection on the pulmonary clearance of Escherichia coli in turkeys.

Thirty-six 1-day-old turkeys were inoculated intranasally with Bordetella avium (BA) strain 838. Noninoculated hatchmates (n = 36) were housed separately. At 2 and 4 weeks of age, 15 inoculated (BA+) and 15 noninoculated (BA-) turkeys were exposed to an aerosol of virulent Escherichia coli. The remaining six BA+ turkeys and six BA- turkeys were used as controls (ie, not exposed to E coli). Turkeys were necropsied on postaerosolization days 0 (immediately after aerosolization), 1, 3, 5, and 7. Lung and tracheal specimens were collected from each turkey for bacterial quantitation and histologic examination. A 1-ml blood sample was collected for detection of bacteremia. Numbers of E coli in lung specimens from 2- and 4-week-old turkeys were not significantly different between BA+ and BA- groups (pooled data over time); however, numbers of E coli isolated from tracheal specimens were significantly greater in BA+ turkeys than those in BA- turkeys. Although the incidence of pulmonary abcesses and E coli bacteremia was greater in 2-week-old turkeys than in 4-week-old turkeys, the incidence was not different between BA+ and BA- turkeys. At both ages, air sacculitis developed more often and was more severe in BA+ turkeys than in BA- turkeys. Hyperplastic bronchus-associated lymphoid tissue was found more often in BA+ turkeys than in BA- turkeys and appeared to be the first site of heterophil infiltration after E coli aerosolization.

Animals↗
PubMed1987

Effects of growth hormone on the adult canine thymus.

The ability of bovine growth hormone therapy to stimulate regeneration of age involuted thymus glands in adult dogs was evaluated. The thymuses of growth hormone treated dogs regenerated, resembling thymic tissue of young dogs. Some of the thymuses of bovine serum albumin treated control dogs also regenerated, but only 2 of 5 control dogs had marked regeneration. White blood cell counts in peripheral blood were not different between groups. Serum thymosin alpha 1 concentrations were not different between groups, but decreased in each group during the treatment period.

Age Factors↗
PubMed1987

Growth hormone treatment stimulates thymulin production in aged dogs.

Diminished thymic morphology and function and a decreased provocative growth hormone (GH) response are characteristic of normal ageing. We have previously demonstrated that bovine growth hormone (bGH) treatment of adult dogs tends to result in a rejuvenation of thymic morphology. The purpose of this study was twofold: (1) to determine concentrations of thymulin (a thymic hormone) in plasma from dogs of various ages, and (2) to evaluate the effect of bGH administration on plasma thymulin concentration and thymus morphology in 'middle-aged' and 'old-aged' dogs. 'Young' (4 months), 'middle-aged' (33-55 months) and 'old-aged' (63-83 months) female beagles served as subjects for this study. Middle- and old-aged dogs were injected with either bGH or bovine serum albumin (control) for 1 month. Thymulin concentration in plasma was determined by the rosette-inhibition bioassay. An age-associated decline in the plasma concentration of thymulin was detected. Plasma thymulin concentration increased in every bGH-treated dog. In middle-aged but not old-aged dogs, bGH treatment resulted in rejuvenation of thymic morphological features as determined by stereological and histomorphological procedures. The results suggest that exogenous GH may be useful for restoration of some immune functions in aged individuals.

Aging↗
PubMed1986

An in vivo model for the study of Bordetella avium adherence to tracheal mucosa in turkeys.

An in vivo model was developed for studies characterizing the adherence of Bordetella avium to the tracheal mucosa of turkeys. Three-week-old turkeys were anesthetized, and the cervical part of the trachea was isolated after tracheostomy was done. A hemostat was applied craniad to the tracheostomy site to occlude the tracheal lumen. Isolated tracheal segments were filled with an aqueous bacterial inoculum for 1 minute, and then excess inoculum and the hemostat were removed. After 1 hour, a 1-cm section was excised from each tracheal segment, and adherent viable bacteria were quantified. Modifications of the procedure were evaluated to produce a model that was technically simple to do, economical, and reproducible. To examine the validity of the model, adherence of B avium was compared with that of Escherichia coli and Staphylococcus aureus. Adherence of B avium to tracheal mucosa was 17 times greater than that with E coli and 1,550 times greater than that with S aureus. Colonization of the tracheal mucosa by B avium was demonstrated in tracheal sections obtained 6 hours after filling with bacterial inoculum. Because the ciliary clearance mechanism of the tracheal segments remained functional, washing of the tracheal lumen had no effect on numbers of associated bacteria. An important advantage of this model over in vitro models is the excellent preservation of the tracheal mucosal surface.

Animals↗
PubMed1986

Adherence of Bordetella avium to turkey tracheal mucosa: effects of culture conditions.

Adherence of Bordetella avium to the tracheal mucosa of turkeys was evaluated, using bacteria grown under different culture conditions. Several solid and liquid media were used at incubation times of 12, 24, 36, or 48 hours with incubation temperatures of 18, 26.5, or 35 C. Adherence of B avium was greatest when the bacteria were grown on solid media at 35 C. Use of Bordet-Gengou or brain-heart infusion agar was associated with significantly greater (P less than 0.05) adherence compared with adherence of bacteria grown on other media. Adherence was greatest, using cultures in the stationary phase of growth; however, with some media, adherence diminished when incubation was extended beyond 36 hours. Adherence of B avium was reduced but not completely prevented when cultures were incubated at 18 C.

Animals↗
PubMed1985

Effect of antibodies to type 1 fimbriae on clearance of fimbriated Escherichia coli from the bloodstream of turkeys.

Young turkeys (n = 20) were inoculated IV with fimbriated, virulent Escherichia coli ECl (O78:K80: H9:F1). Blood samples were collected for bacterial quantitation at postinoculation minutes (PIM) 10, 20, 30, 40, 50, and 60. Immediately after the PIM 30 sampling, the turkeys were allotted into 4 groups (5 turkeys/group) and were injected IV with 1 of the following antisera: group 1, antibodies to F1 fimbriae (AF); group 2, antibodies to E coli O78 antigen (AO); group 3, antibodies to live, fimbriated (F1+) homologous E coli (ALEC); or group 4, normal turkey serum (NTS) collected from a healthy turkey. Compared with NTS, ALEC and AO caused a significant reduction in blood-borne E coli, whereas AF did not reduce bacterial numbers. In addition, 2 groups of 10 turkeys were inoculated IV with live, F1+ or nonfimbriated (F1-) E coli ECl. Numbers of viable bacteria were determined in blood samples and liver specimens collected 2 minutes after inoculation. Compared with F1- bacteria, significantly more F1+ bacteria were found in liver specimens and significantly fewer F1+ bacteria were found in blood samples. Results indicated that antibodies to F1 fimbriae do not enhance clearance of F1+ E coli from the bloodstream of turkeys probably because F1+ bacteria are selectively cleared by the liver, even without antibody.

Animals↗
PubMed1984

Tracheal lesions in young turkeys infected with Bordetella avium.

Forty-six turkeys were inoculated intranasally with Bordetella avium at 3 days of age. Inoculated and non-inoculated turkeys (n = 72) were necropsied sequentially from post-exposure days (PED) 3 to 53. Tracheal lesions were studied histologically. Mild fibrinopurulent tracheitis, associated with bacterial colonization of ciliated epithelium, was seen at PED 7 to 10. At PED 14 and 21, there were numerous bacterial colonies, loss of ciliated cells, epithelial hyperplasia, depletion of mucus, and diffuse infiltration of lymphocytes and macrophages. At PED 28, the mucosa and tracheal rings were severely distorted. The mucosal epithelium, composed of immature epithelial cells and nononuclear leukocytes, had formed prominent longitudinal folds. Mucous glands were cystic and lined by low cuboidal epithelium. At PED 42 and 53, tracheas appeared normal, except for residual distortion of tracheal rings and shortened luminal epithelium.

Agglutination Tests↗
PubMed1983

Pathology of liver granulomas in turkeys.

Liver granulomas from five- and seven-week-old turkeys were studied by light and electron microscopy and by bacterial culture. Granulomas of five-week-old poults were composed of a caseous, necrotic center surrounded by consecutive zones of heterophils, giant cells, macrophages, and finally by lymphocytes. Tissue Gram and modified Dieterle stains demonstrated numerous gram-positive, filamentous bacteria in necrotic centers with radial extension of the bacteria to the zone of giant cells. Electron microscopic examination revealed septate, filamentous bacteria within an electron-dense milieu between heterophils, macrophages, and giant cells. An anaerobic, gram-positive bacillus and a staphylococcus were isolated from most granulomas examined. In broth, the bacillus formed long filaments or chains morphologically similar to those in tissue sections. The bacillus was identified tentatively as Eubacterium tortuosum. The staphylococcus had cultural reactions typical for Staphylococcus epidermidis. Intravenous inoculation of three-week-old poults with a mixture of E. tortuosum and S. epidermidis produced granulomas in liver and spleen and multiple mucosal ulcers in the duodenum and colon.

Animals↗
PubMed1982

Effect of passive immunization on phagocytosis of blood-borne Escherichia coli in spleen and liver of turkeys.

Clearance of Escherichia coli from blood and localization in tissues were studied by culture and microscopy in nonimmunized and passively immunized turkeys after IV inoculation. In nonimmunized poults, high mortality was associated with persistence of large numbers of E coli in the blood. In immunized poults, rapid clearance of E coli from blood was associated with large numbers of E coli in hepatic sinusoids and fewer bacteria in the spleen. An electron-dense, fibrillogranular coat covered extracellular E coli in immunized poults, but not in nonimmunized poults. Rapid clearance of virulent E coli from blood was markedly enhanced by antibody-dependent phagocytosis in liver.

Animals↗
PubMed1981

Experimental intoxication of guinea pigs with multiple doses of the mycotoxin, penitrem A.

Young female guinea pigs were fed various doses of penitrem A very 3 days for 3 weeks. Guinea pigs fed penitrem A had muscle tremors, seizures, and ataxia, and total weight gains were less than those of control guinea pigs. Histologic examination of multiple tissues and electron microscopic examination of liver and kidney revealed no differences between guinea pigs fed penitrem A and controls. Sera harvested at necropsy from guinea pigs fed penitrem A and control guinea pigs did not differ significantly in mean values of two liver enzymes (ornithine carbamoyltransferase and sorbitol dehydrogenase), complement, total protein, and differential proteins (albumin; alpha 1, alpha 2, beta, and gamma globulins). Results of this study indicate that penitrem A causes only central nervous system dysfunction; evidence of cytotoxicity for extraneural tissues was not found.

Animals↗
PubMed1981

Interaction of blood-borne Escherichia coli with phagocytes of spleen and liver in turkeys.

The response of splenic and hepatic macrophages to blood-borne virulent and avirulent Escherichia coli was studied in 3-week-old turkeys. Bacterial titers in blood, spleen, and liver were determined for 20 minutes after IV injection of E coli. Spleen and liver were examined by light and electron microscopy. Blood titers of avirulent E coli were reduced to 1/3,000 of their original level in 20 minutes, whereas titers of virulent E coli were only slightly reduced. The E coli localized in macrophages of hepatic sinusoids and splenic reticular sheaths (ellipsoids). In liver, phagocytosis was more efficient for avirulent E coli than for virulent E coli. In splenic macrophages, phagosomal membranes were separated from ingested avirulent E coli by a prominent space, whereas phagosomal membranes surrounding virulent E coli were wavy and closely apposed to the bacterial surface. The appearance of phagosomes may reflect the capacity of splenic macrophages to kill intracellular E coli. Cultural and histopathologic results indicated that virulent E coli resisted trapping and killing by macrophages of spleen and liver.

Animals↗
PubMed1979

Intoxication of dogs with the mycotoxin penitrem A.

Mycotoxicosis caused by ingestion of moldy cream cheese was suspected in two dogs with severe muscle tremors and generalized seizures. Penicillium crustosum and its toxin, penitrem A, were isolated from the moldy cream cheese.

Animals↗
PubMed1979

Natural occurrence of the mycotoxin penitrem A in moldy cream cheese.

The occurrence of the mycotoxin penitrem A in refrigerated cream cheese that was involved in the intoxication of two dogs is described. Penitrem A and the fungus Penicillium crustosum were isolated from the cream cheese and identified. This is believed to be the first definitive case of the natural occurrence of penitrem A.

Animals↗
PubMed1978

Comparative pathologic findings of Escherichia coli infection in birds.

Of the 3 respiratory tract disease syndromes that occur in birds associated with Escherichia coli infection, acute colisepticemia, characterized by hyperemic and swollen viscera, tended to occur in young birds. Subacute fibrinopurulent serositis involving air sacs and pericardium was more common in older birds. Chronic granulomatous pneumonitis was not seen as flock epornitics but as chronic disease in birds dying in small numbers some time after one of the previously mentioned forms of the disease. Serotypes of 100 E coli isolates from turkey colibacillosis revealed most to be O1, O2, O36, or O78. Virulence of the isolates, as conducted by IV inoculation of 6-week-old turkeys, showed O78 strains to be highly virulent and O36 strains to vary in virulence.

Air Sacs↗