Biomedical subjects

V E Valli

Publications and source records attributed to V E Valli.

At least 37 records · Page 2Linked to original sources

PubMed1997

Effects of tris(4-chlorophenyl)methanol on the rat following short-term oral exposure.

The systemic toxicity of tris(4-chlorophenyl)methanol (TCPM) was studied in male and female rats following 4 weeks dietary exposure dosed at 1, 10 and 100 ppm. An increased spleen to body weight ratio was observed in males at 10 and 100 ppm and in females at 100 ppm. An increased liver to body weight ratio was detected in both sexes at 100 ppm. Dose-related increases in hepatic Phase-I (AH, APDM, EROD and PROD) and Phase-II (UDPGT, GST) enzyme activities were observed generally at 10 and 100 ppm, with the elevation in PROD activity being the most marked. Increased urinary ascorbic acid was detected in both males and females after 1 week of treatment at 100 ppm and after 4 weeks of treatment at 10 and 100 ppm. At 10 and 100 ppm, elevated % lymphocytes were found in males, and higher white blood cell and lymphocyte counts were observed in females. In the liver, mild to moderate cytoplasmic changes consistent with proliferation of smooth endoplasmic reticulum were present in rats of both sexes at 10 and 100 ppm, and increased number of hepatocytes undergoing apoptosis were observed in male rats at 100 ppm. Mild splenic changes consisting of sinus hyperplasia in males and females at 100 ppm and mantle zone atrophy in males at 100 ppm were also observed. It was concluded that TCPM at a dietary concentration of 10 ppm (equivalent to 1.2 mg/kg/day) produced systemic changes in rats that included various hepatic effects, increased splenic weight, and modulations in white blood cells and lymphocyte counts.

Administration, Oral↗

PubMed1997

Subchronic oral toxicity of di-n-octyl phthalate and di(2-Ethylhexyl) phthalate in the rat.

The subchronic oral toxicity of di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP) was studied. Groups of 10 male and 10 female Sprague-Dawley rats were administered DEHP in the diet at 0, 5, 50, 500 or 5000 ppm for 13 wk. In a separate study, groups of 10 male and 10 female Sprague-Dawley rats were given DNOP (5, 50, 500 and 5000 ppm) in the diet while control groups received basal diet containing 4% corn oil and positive control groups were fed a diet containing 5000 ppm DEHP. Growth rate and food consumption were not affected by treatment with either compound. Hepatomegaly was observed in the highest dose groups of both sexes administered DEHP but not in the DNOP-treated animals. At the highest dose, DNOP caused threefold (females) and 12-fold (males) increases in liver ethoxyresorufin-O-deethylase activity while DEHP did not. Mild changes in serum biochemistries were mostly confined to rats in the highest dose group of DEHP, and included increased serum albumin and albumin/globulin ratio in both sexes and decreased cholesterol in female rats. Mild vacuolations in the Sertoli cells were observed in male rats exposed to 500 ppm DEHP. At 5000 ppm DEHP, there was mild to moderate seminiferous tubule atrophy and Sertoli cell vacuolation in males, and rats of both sexes showed hepatic peroxisome proliferation. Both DEHP and DNOP at 5000 ppm caused mild histological changes in the thyroid consisting of reduced follicle size and colloid density, and the liver consisting of endothelial nuclear prominence, nuclear hyperchromicity and anisokaryosis. There was accentuation of zonation of the hepatic lobules and increased perivenous cytoplasmic vacuolation in DNOP-treated rats. Trace quantities (3-5 ppm) of DEHP and DNOP were detected in the liver, and 15-31 ppm were found in adipose tissue of the highest dose groups. The no observed-effect-level was judged to be 50 ppm in the diet or 3.7 mg/kg body weight/day for DEHP, and 500 ppm or 36.8 mg/kg body weight/day for DNOP.

Administration, Oral↗

PubMed1997

The subchronic toxicity of acridine in the rat.

The subchronic toxicity of acridine was investigated in rats following dietary exposure at 0, 1, 10, 100 and 500 ppm for 13 weeks. The growth rate and food consumption were not affected by treatment and no clinical signs of toxicity were observed. There was a slight but significant decrease in spleen weight, both in absolute terms and as a percent of body weight, in the 500 ppm males and a slight increase in absolute thymus weight in the females of the same dose group. Both hepatic ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-dealkylase (PROD) activities were slightly, but significantly, elevated in females in the 500 ppm dose group. No haematological or other biochemical changes were observed. Females also displayed dose-related increases in inorganic phosphate and uric acid levels. Treatment-related histopathological changes were seen in the thyroid, liver and kidney and included hepatic anisokaryosis and vesiculation of nuclei and glomerular adhesions, reticulin sclerosis and nuclear pyknosis in the kidney. Residue data showed a dose-dependent accumulation of acridine in liver, kidney and adipose with the highest concentration being found in the fat of the 500 ppm dose group. Based on these data, the no observable adverse effect level of acridine was judged to be 100 ppm or 12 mg/kg bw/day.

Acridines↗

PubMed1997

The immunophenotypic characterization of bovine lymphomas.

A prospective analysis of 38 cases of bovine lymphoma was performed. Thirty-five of the lymphomas were considered enzootic because of serologic or molecular biologic association with the bovine leukemia virus (BLV). The three remaining cases were in cattle < 1 year of age and were not associated with BLV and hence were considered sporadic lymphomas. Utilizing the national cancer Institute Working Formulation for the morphologic classification of human non-Hodgkin's lymphoma, 54.3% (19/35) of the enzootic lymphomas were classified as the diffuse large cleaved cell type. The cells of the 35 enzootic lymphomas expressed a consistent immunophenotype represented by MHCII+, gamma-heavy chain+, and lambda-light chain+; this constellation of markers indicated a mature B-cell phenotype. The three sporadic lymphomas failed to express MHCII antigen despite the presence of other B-cell antigens. There was no correlation between morphologic cell type and immunophenotype in these bovine lymphomas.

Animals↗

PubMed1996

Toxicity of 2,4,4'-trichlorobiphenyl in rats following 90-day dietary exposure.

The toxicity of 2,4,4'-trichlorobiphenyl (PCB 28) was investigated in rats after a 90-d dietary exposure. Groups of 10 male and 10 female weanling Sprague-Dawley rats were administered PCB 28 in the diet at 0, 0.05, 0.50, 5.0, or 50.0 ppm for 13 wk. Growth rate and food consumption were not affected by treatment, and no clinical signs of toxicity were observed. Mottled liver was noted in both control and PCB-treated males, but was found with increased incidence in the highest treatment group. Increased urinary ascorbic acid and hepatic microsomal ethoxyresorufin O-deethylase activity were observed in the 50.0 ppm group of both sexes. The vitamin A content in liver, lung, and kidney was not significantly affected by treatment. Analysis of brain biogenic amines showed a decreased dopamine concentration in the substantia nigra region of female rats receiving 0.5 ppm PCB 28 and higher doses. Female rats appeared to be more sensitive than males to the neurochemical effects of PCB 28. Dose-dependent histologic changes were observed in the thyroid and liver, with biologically significant changes occurring at 5.0 ppm and above. Based on these data, the no observable-adverse-effect level (NOAEL) for this PCB congener was considered to be 0.5 ppm in diet or 36 micrograms/kg body weight/d.

Administration, Oral↗

PubMed1996

Systemic toxicity of a bitumen upgrading product in the rat following subchronic dermal exposure.

The subchronic toxicity following dermal exposure to a synthetic fuel, heavy gas oil No. 2 fraction of bitumen upgrading product (B-HGO II) was studied in the rat. B-HGO II was applied on the dorsal skin of rats at doses of 8, 20, 50 and 125 mg/kg bw/day daily for 13 weeks. Control animals received normal saline and positive controls received a medium-boiling coal liquefaction product (CLP) at 125 mg/kg bw/day. Both male and female rats in the treatment groups had reduced body weight gain, and males in the highest dose group were terminated in the 5th week due to overt toxicity. Increased liver weight relative to body weight was observed in males and females starting at 8 mg/kg. Increased relative heart and spleen weights were observed in males and females starting at the two intermediate doses (20, 50 mg/kg). Increased relative kidney weight was detected in males at 50 mg/kg and females at 125 mg/kg. Increased serum cholesterol was observed in both sexes starting at 50 mg/kg while elevated serum glucose was present in females starting at 8 mg/kg. Significant changes in AH, APDM and EROD activities were observed in treated rats of both sexes. Reduced red blood cell counts were detected in males starting at 8 mg/kg and females at 20 mg/kg. Microscopic examination of blood smears, spleen and hemosiderin accumulation patterns, as well as analysis of FEP and serum TIBC levels indicated that the cause of anemia was primarily intravascular hemolysis and secondarily iron deficiency. Marked thymic atrophy and thyroid abnormalities were the most prominent histological changes followed by changes in bone marrow (myelofibrosis) and liver. Both B-HGO II and CLP (positive control) caused kidney changes characterized by cytoplasmic inclusions and lesions in the tubular cells, which were observed in 50 mg/kg males but not in the females. B-HGO II was considered to be toxic at a subchronic dermal exposure level as low as 8 mg/kg/day.

Aminopyrine N-Demethylase↗

PubMed1996

Histopathological changes in the lymphoid tissues of sheep exposed to the bovine immunodeficiency-like virus.

Six yearling sheep were inoculated intraperitoneally with peripheral blood from two sheep infected with the bovine immunodeficiency-like virus (BIV) strain R29. An additional five sheep served as sham-inoculated controls. Of the six sheep given BIV, five seroconverted, one of them remaining seropositive for the duration of the study. The polymerase chain reaction demonstrated BIV provirus in three of the five serologically positive animals. At necropsy, 1 year after inoculation, histological changes were found only in the lymphoid tissues. In sheep exposed to BIV, mild though significant increases were seen in the (1) number of splenic periarteriolar lymphoid sheaths, (2) number of secondary follicles in hilar and prescapular or popliteal lymph nodes, and (3) medullary sinus cellularity in prescapular and popliteal lymph nodes.

Animals↗

PubMed1996

Primary epitheliotropic alimentary T-cell lymphoma with hepatic involvement in a dog.

The anatomic forms of lymphoma are multicentric, alimentary, thymic, cutaneous, and leukemic. Correlations between cell type and topographic distribution of lymphomas is not well documented, but there are more plasmacytoid tumors in the gut, skin, and spleen, which suggests that these are areas of malignant transformation preceded by a period of benign immune hyperplasia. Alimentary forms of lymphoma can be preceded by lymphocytic-plasmacytic enteritis. In the present case, an epitheliotropic alimentary form of T-cell lymphoma with hepatic involvement and concomitant lymphocytic-plasmacytic enteritis was diagnosed in an 8-year-old male Labrador Retriever. The lymphoma was characterized by the accumulation of atypical lymphocytes in the lamina propria and mucosal epithelium of the jejunum. The lymphocytes were identified as T-cell lineage using a polyclonal rabbit antisera to the human pan-T-cell determinant CD-3. The "homing" nature of the neoplasm resembles the epidermotropic form of cutaneous T-cell lymphoma.

Animals↗

PubMed1995

Toxicity of PCB 77 (3,3',4,4'-tetrachlorobiphenyl) and PCB 118 (2,3',4,4'5-pentachlorobiphenyl) in the rat following subchronic dietary exposure.

The toxicity of 3,3',4,4'-tetrachlorobiphenyl (PCB 77) and 2,3',4,4',5-pentachlorobiphenyl (PCB 118) was investigated in rats following subchronic dietary exposure. Groups of 10 male and 10 female weanling Sprague-Dawley rats were administered PCB 77 in the diet at 0, 10, 100, 1000, or 10,000 ppb for 13 weeks. PCB 118 was administered to males in the diet at 0, 10, 100, 1000, and 10,000 ppb, while the female groups received 0, 2, 20, 200, or 2000 ppb of the congener for 13 weeks. Growth rate and food consumption were not affected by treatment. No clinical signs of toxicity were observed. Increased spleen weight occurred in male rats fed 1000 or 10,000 ppb PCB 77. Male rats receiving 10,000 ppb PCB 118 had increased liver weight and hepatic ethoxyresorufin O-deethylase (EROD) activity. Increased hepatic EROD activity but not liver weight was observed in female rats given the 2000-ppb PCB 118 diet. Increased EROD activity was also noted in male rats given 10,000 ppb and in female groups receiving 1000 or 10,000 ppb PCB 77. Male rats exposed to 10,000 ppb PCB 77 had decreased vitamin A in the liver and lung and elevated levels in the kidney. Liver vitamin A of both 1000- and 10,000-ppb PCB 77 female groups was decreased. PCB 118 had no effects on tissue vitamin A at the levels studied. No hematological changes or serum biochemical changes were seen in any of PCB 118- and PCB 77-treated groups, nor were liver uroporphyrin levels altered. A reduction in dopamine and homovanillinic acid in substantia nigra region of the brain was observed in female rats fed 2000 ppb PCB 118, while 10,000 ppb PCB 77 was associated with an elevation in 3,4-dihydroxyphenylacetic acid in the nucleus accumbens region of male rat brains. Mild to moderate changes were observed in the liver and thyroid of rats given PCB 77 or PCB 118. PCB 118 accumulated in a dose-dependent manner in fat and to a much lesser extent in liver. In contrast, very low levels of PCB 77 residue were found in the tissues examined. Based on the above data it was concluded that NOAEL of PCB 77 is 100 ppb in diet or 8.7 micrograms/kg and that of PCB 118 is 200 ppb in diet or 17 micrograms/kg body wt/day.

Animal Feed↗

PubMed1995

Pathology of canine bladder and urethral cancer and correlation with tumour progression and survival.

Biopsy and necropsy specimens, comprising 107 primary carcinomas and three mesenchymal tumours, were reviewed from 110 dogs with cancer of the bladder, urethra, or both. Histological classifications developed for the assessment of human bladder cancer were found to be readily applicable to the dog. These classifications are based on histological features, including the pattern of growth, the cell type, the grade of transitional tumour and the depth of invasion of the bladder wall. Features associated with localized disease in canine transitional cell carcinoma included papillary architecture, "in-situ" tumour, low tumour grade and a strong peritumoral lymphoid cell reaction. Features of tumours with metastasis included infiltrating and non-papillary architecture, increasing tumour grade, depth of invasion, vascular invasion and presence of peritumoral fibrosing reaction. Wide variability was found within single tissue samples, indicating that multiple sample sites are necessary for the adequate characterization of a given lesion. Statistically significant correlations were found between: tumour grade and depth of invasion (P < 0.0001); tumour grade and presence of metastases (P < 0.029); and peritumoral desmoplasia and metastases (P < 0.029). It was concluded that canine bladder cancer could be classified for the purpose of clinical management with a modified World Health Organization system as developed for human tumours.

Animals↗

PubMed1994

Short-term toxicity of bitumen upgrading products in the rat following repeated dermal exposure.

Light gas oil (B-LGO), heavy gas oil No. 1 (B-HGOI), and heavy gas oil No. 2 (B-HGOII) fractions of bitumen upgrading products (BUPs) were applied on the dorsal skin of rats at 25 mg/kg bw/day (low dose), 100 mg/kg bw/day (intermediate dose), and 400 mg/kg bw/day (high dose) for 4 weeks. Control animals received normal saline while positive controls received a medium boiling coal liquefaction product (CLP) at 100 and 400 mg/kg bw/day. Reduced food comsumption and growth suppression were observed in males and females treated with B-HGOI, B-HGOII, and CLP, but only in males receiving B-LGO. Increased relative spleen, kidney, and liver weights were observed in animals treated with B-HGOI, B-HGOII, and CLP, but not in control or LGO groups. A dose-related increase in absolute and relative liver weight was most marked in animals receiving B-HGOII where a significant increase was observed starting at the low dose, followed by those receiving B-HGOI and CLP. Appearance of pale foci on the splenic capsule and increases in spleen/body weight ratio were limited to animals receiving B-HGOI and B-HGOII. Decreases in hematocrit and RBC and increase in percentage of reticulocytes were observed in animals of both sexes receiving B-HGOI and B-HGOII. Female rats appeared to be more severely affected because significant decreases in hemoglobin and RBC were observed in animals receiving the low dose of B-HGOII and the intermediate dose of B-HGO-I. Increased serum cholesterol was observed in B-HGOII-treated females at all dose levels, and in males starting at the intermediate dose. Histological changes were observed in the thymus gland, where moderate to marked cortical atrophy was noted in male and female rats receiving the high dose of B-HGOI and B-HGOII, and in the bone marrow, where the most significant abnormality was the presence of focal myelofibrosis in some male rats treated with B-HGOI and B-HGOII. Mild to moderate histological changes were found in the thyroid, liver, and spleen of rats of all treatment groups. Changes in the skin included moderate hyperkeratosis in females receiving high doses of B-LGO and in animals of both sexes receiving high doses of B-HGOI, and moderate to marked epidermal hyperplasia in rats receiving high doses of B-HGOI.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Cutaneous↗

PubMed1994

Haematological and lymphocyte subset analyses in sheep inoculated with bovine immunodeficiency-like virus.

Bovine immunodeficiency-like virus (BIV) was passaged in vivo by intraperitoneal transfusion of ovine whole blood. Prior to transfusion, the recipient sheep were given sodium thioglycolate intraperitoneally to induce mild non-suppurative inflammation. The anti-BIV antibody response, haematology, and peripheral blood lymphocyte subsets (B, gamma delta, CD2+, CD4+ and CD8+) of recipient sheep were assessed for one year following transfusion. Passaging was successful since serum anti-BIV antibody responses were detected in 5 of the 6 recipient sheep; 1 of the 5 remained seropositive throughout the study. Lentivirus was not isolated from the recipient sheep, but provirus was detected by the polymerase chain reaction in DNA from peripheral blood leukocytes in 3 of the 5 sheep that seroconverted. In the BIV-inoculated sheep, neutrophils and eosinophils were significantly increased (p < or = 0.05) at 3 months and between 6 and 8 months postinoculation, respectively. B, CD2+ and CD4+ cells and the CD4+/CD8+ ratios were significantly increased (p < or = 0.05) 2 months postinoculation. Mild, transient haematological changes occurred in BIV-exposed sheep, but illness was not detected in the year.

Animals↗

PubMed1994

Nonrandom chromosomal abnormalities in bovine lymphoma.

Despite detailed knowledge of the genetic map of the bovine leukemia virus (BLV), the mechanism whereby BLV infection results in transformation and B-lineage restriction of tumors is poorly understood. The aim of this study was to gain new insight into pathogenetic mechanisms of BLV-induced tumorigenesis by determining the karyotypes of BLV-associated lymphomas in cattle. Metaphases in cells from lymphoid tumors from 20 mature dairy cows were banded and analyzed after short-term, unstimulated culture. Nineteen out of twenty cases exhibited clonal abnormalities, 17 cases were hyperdiploid, and 16 cases had extremely complex chromosomal changes. Recurrent chromosomal anomalies were identified and there was clear evidence for the evolution of increasing chromosomal instability in 12 cases. The most common abnormalities were the acquisition of additional small chromosomes (23-29); trisomy of chromosomes 5 and 7, and Robertsonian translocations and isochromosome rearrangements involving chromosomes 10, 12, 23, and 26. Monosomy X, trisomy X, and translocations involving the X chromosome were also detected. Chromosomes 2, 3, 4, 6, 8, 9, 11, 13, 14, 19, and 21 were infrequently involved in either structural or numerical changes. Structural rearrangements of chromosomes 10, 12, 23, and 26 may reflect primary abnormalities occurring relatively early in transformation, whereas trisomy 5 may be an extremely common secondary abnormality. While comparison of these findings with the current bovine gene map raises intriguing possibilities for pathogenetic mechanisms, further studies are needed before hypothetical mechanisms linking chromosomal abnormalities with BLV-induced transformation can be made.

Animals↗

PubMed1994

Combined effects of mercury and hexachlorobenzene in the rat.

The objective of the present study was to assess the potential interactive effects of two Great Lakes chemical contaminants, hexachlorobenzene (HCB) and mercury (HgCl2). Groups of 10 female Sprague-Dawley rats were administered by gavage single doses of HCB (400, 600 mg/kg b.w. in corn oil), HgCl2 (10.0, 12.5 mg/kg b.w. aqueous) or combinations of both followed by observation for clinical signs of toxicity for 14 days. Five animals from treatment groups died before the termination of the study; one animal each in 600 mg HCB, 400 mg HCB + 10 mg HgCl2, and 600 mg HCB + 10 mg HgCl2, and two animals in 600 mg HCB + 12.5 mg HgCl2. The surviving animals were necropsied at the termination of the study, and hematological, clinical chemistry, histopathological and tissue residue analyses were performed. Relative liver weights were increased in both low and high dose groups of HCB but not in animals treated with HgCl2 alone. Co-administration of HgCl2 did not alter the HCB effects on the liver weight of the animals. Serum cholesterol levels were increased in all the groups receiving HCB but not HgCl2. No interactive effects on other serum parameters were seen in animals administered with both chemicals. Mild to moderate morphological changes occurred in the liver, thyroid, thymus, ovary and bone marrow of rats exposed to HCB or HCB+HgCl2, and in the kidney of HgCl2 or HgCl2+HCB treated animals. More severe histological changes occurred in the groups receiving both chemicals. The histological effects appeared to be additive. It was concluded that co-administration with HCB and HgCl2 resulted in additive effects in some of the endpoints measured but no synergism or antagonism was observed.

Administration, Oral↗

PubMed1993

Hexachlorobenzene toxicity in the monkey primordial germ cell without induced porphyria.

Hexachlorobenzene is a persistent chlorinated organic chemical that has been detected in many tissues from a variety of species including human ovary and human ovarian follicular fluid. When administered in high dosage to nonhuman primates, hexachlorobenzene causes destruction of ovarian primordial germ cells in association with systemic toxicity. The purpose of these experiments was to assess relative ovarian germ cell sensitivity at much lower dosages of hexachlorobenzene that do not produce systemic effects and additionally to evaluate oocyte function by means of the response to superovulation, fertilization, and embryo cleavage during a cycle of in vitro fertilization in the cynomolgus monkey. Hexachlorobenzene in dosages of 0.1, 1.0, and 10.0 mg/kg/day was administered orally by gelatin capsule for 90 days. There was a dose-dependent accumulation of HCB in serum and other tissues without any change in the serum estradiol response to human menopausal gonadotropin, oocyte recovery, oocyte maturation, oocyte fertilization in vitro, and early embryo cleavage rate. There was a dose-related toxic effect observed in primordial germ cells at the lowest dose despite no evidence of systemic or hepatic effects. As there were no changes in the urinary porphyrin excretion, the mechanism of hexachlorobenzene ovotoxicity may be distinct from hexachlorobenzene-induced cytochrome P-450-dependent inhibition of uroporphobilinogen decarboxylase in the liver, although such intraovarian metabolism cannot be excluded.

Animals↗

PubMed1993

Preparation and transfusion of canine platelet concentrates.

A protocol was developed for preparation of platelet concentrates (PC) to support thrombocytopenic dogs. Four clinically normal dogs with platelet counts that ranged from 200 to 330 x 10(9) platelets/L were used as donors. One unit (450 ml) of blood was collected by venipuncture into a double blood bag. Whole blood (WB) was centrifuged for 4 minutes at 1,000 x g (braking time = 2 minutes, 30 seconds) to prepare platelet-rich plasma (PRP). The PRP was expressed into the satellite bag and was centrifuged for 10 minutes at 2,000 x g (braking time = 2 minutes, 36 seconds). The platelet-poor plasma was expressed, leaving 40 to 70 ml of plasma and the pelleted platelets in the satellite bag. The resulting PC was left undisturbed for 60 minutes to promote disaggregation, and the platelets were then resuspended by gentle manual agitation. Forty-eight PC were prepared. Mean (+/- SD) platelet yield from WB to PRP was 78 (+/- 13)% (range, 35 to 97%); yield from PRP to PC was 94 (+/- 6)% (range, 75 to 100%); and overall yield (PC from WB) was 74 (+/- 13)% (range, 36 to 91%). Mean PC platelet count was 8.0 (+/- 3.0) x 10(10) platelets/PC (range, 2.3 to 13.4 x 10(10) platelets/PC). The WBC content was 0.1 to 2.3 x 10(9) platelets/PC, representing 3 to 74% of WBC in the WB. Hematocrit was 0.1 to 26.2%. Results of bacterial and fungal culturing were negative. The PC were irradiated (18 Gy) and transfused to 5 cross-matched dogs undergoing bone marrow transplantation that developed profound thrombocytopenia of up to 8 weeks' duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Clinical and pathological findings in dogs following supralethal total body irradiation with and without infusion of autologous long-term marrow culture cells.

We developed a canine model for autologous bone marrow transplantation (AuBMT) with long-term marrow culture (LTMC) cells. Marrow was harvested from nine normal dogs. Harvests from dogs 2-7 were placed into 21 day LTMC. Cells in LTMC from dogs 4-7 were labelled with the neomycin phosphotransferase gene neo. Dogs were given 60Co total body irradiation (TBI) and then infused with LTMC cells: dog 1 received 500 cGy TBI and 2.08 x 10(8)/kg uncultured marrow cells. Dogs 2-7 received 600-800 cGy TBI and 0.07-0.45 x 10(8)/kg LTMC cells. Dogs 8 and 9 received 600 and 800 cGy TBI, respectively, but no infusion of marrow or LTMC cells. For all dogs, profound myelosuppression developed during week 1 and pyrexia developed during week 2. Enrofloxacin was given from one day before TBI until a peripheral neutrophil count > 1.0 x 10(9)/L was achieved, which eliminated Escherichia coli from feces. Dogs 1, 2 and 5-9 also received gentamicin and/or combination beta-lactam antibiotics. Numerous platelet transfusions were needed to control hemorrhages in all dogs except dog 1. Dog 1 achieved neutrophils > 1.0 x 10(9)/L on day 15, while dogs 2 and 5-9 achieved this count on days 33-48. Dogs 3 and 4 died on days 17 and 18, respectively, of beta-hemolytic streptococcal sepsis and hemorrhage, with no evidence of hematopoiesis at necropsy. The marker gene, neo, was documented in lymphoid and myeloid cells of dogs 5-7 up to 21 months post-AuBMT. Our studies indicate that dogs can recover following supralethal TBI and can survive the delayed engraftment associated with AuBMT using LTMC cells, if they receive intensive platelet and antimicrobial therapy. Used prophylactically for such therapy, enrofloxacin achieved selective intestinal decontamination, but did not prevent sepsis when used as the sole antimicrobial agent during myelosuppression. Furthermore, our studies indicate that infused LTMC cells, at the above doses, can contribute to hematopoietic recovery, but are not essential for recovery following TBI, and do not shorten the period of prolonged profound myelosuppression induced by TBI.

Animals↗

PubMed1992

Autologous transplantation of canine long-term marrow culture cells genetically marked by retroviral vectors.

Retroviral infection of bone marrow cells in long-term marrow cultures (LTMCs) offers several theoretical advantages over other methods for gene transfer into hematopoietic stem cells. To investigate the feasibility of this approach in a large animal model system, we subjected LTMCs from nine dogs to multiple infections with retrovirus containing the neomycin phosphotransferase gene (neo) during 21 days of culture. Feeder layers, cocultivation, polycations, and selection were not used. The in vitro gene transfer efficiency was 70% as determined by polymerase chain reaction amplification of neo sequences in colony-forming unit granulocyte-macrophage (CFU-GM) obtained from day-21 LTMCs. Day-21 LTMC cells were infused into autologous recipients with (four dogs) and without (three dogs) marrow-ablative conditioning. At 3 months posttransplant, up to 10% of marrow cells contained the neo gene. This percentage declined to 0.1% to 1% at 10 to 21 months posttransplant. Neo was also detected in individual CFU-GM, burst-forming unit-erythroid (BFU-E), and CFU-Mix progenitors derived from marrow up to 21 months postinfusion and in cultures of peripheral blood-derived T cells up to 19 months postinfusion. There was no difference in the percentage of neo-marked cells present when dogs that received marrow ablative conditioning were compared with dogs receiving no conditioning. Detection of neo-marked marrow cells almost 2 years after autologous transplantation in a large mammalian species shows that retroviral infection of marrow cells in LTMCs is a potentially nontoxic and efficient protocol for gene transfer. Further, our results suggest that marrow conditioning and in vivo selection pressure to retain transplanted cells may not be absolute requirements for the retention of genetically marked cells in vivo.

Animals↗