Primary Site Of Inoculation Research Articles

Effect of tar condensate from smoking tobacco and water-extract of snuff on the oral mucosa of mice with latent herpes simplex virus

Upper lips were inoculated with virus to establish a latent infection in the trigeminal ganglia. During the latent period, tobacco smoke tar condensate or water-extract of snuff were topically applied to the primary inoculation site for two or three consecutive months. Tar condensate induced re-activation of latent HSV in the ganglia of 10 to 20 per cent of animals but snuff extract did not. Infectious virus was also detected in lips after the chronic application of tar condensate in 10 per cent of animals. Three months' exposure to tobacco produced epithelial dysplasia and other changes in a significant number of latent HSV-infeeted mice, whereas tobacco alone did not induce dysplasia in the labial epithelium of uninfected mice.

Protection against experimental toxoplasmosis by adoptive immunotherapy.

The role of humoral and cell-mediated immunity against toxoplasmosis in experimentally infected guinea pigs was examined by using a syngeneic passive transfer system. Serum or spleen and lymph node cells from guinea pigs immune to infection with the RH strain of Toxoplasma gondii conferred partial protection against symptomatic disease in recipient guinea pigs. This result was based on the reduced dissemination or growth of T. gondii parasites from the primary inoculation site to various selected organ sites of the recipients of immune serum or cells. Similar levels of partial protection against disseminated toxoplasmosis occurred in animals infused with cell suspensions enriched for immune T cells, whereas treatment of immune cells with a monoclonal anti-guinea pig T cell antibody plus complement abolished their ability to transfer resistance. These findings provide substantial direct evidence implicating both cellular and humoral components of the immune response as important effector mechanisms in host resistance to toxoplasmosis.

Metastasis of Rous Sarcoma Tumors in Chickens is Influenced by the Major Histocompatibility (B) Complex and Sex

Six-week-old second generation progeny from the cross of inbred Lines 61 and 151, segregating into three major histocompatibility (B) complex groups (B2/B2, B2/B5, and B5/B5). were inoculated subcutaneously in the wingweb with one of three pseudotypes of Rous sarcoma virus. Chickens that died during a 10-week period after inoculation were necropsied and scrutinized for gross metastasis and histological sections of at least one lesion per affected organ examined for Rous sarcoma-transformed cells, By definition, a metastatic tumor was one located in an organ or tissue other than the primary inoculation site and having the histological appearance of a Rous sarcoma.Sarcomas developed in 1144 chickens, 390 of which died with tumor. For B2/B2, compared to B5/B5 hosts, mortality was 8 vs. 93%, median days to death were 45 vs. 31, and metastatic frequency was significantly lower, 32 vs. 58%. Disseminated lesions were significantly less frequent in females than males and grew preferentially in the heart and pericardial sac. Because the frequency of metastasis was significanlty lower in B2/B2 than in B5/B5 chickens, a gene(s) within, or closely linked to, the B complex sharply retards the spread of Rous sarcoma virus-induced tumors.

Life-Threatening Cat-Scratch Disease in an Immunocompromised Host

We describe a renal allograft recipient with cat-scratch disease in whom refractory hypotension, severe metabolic acidosis, pulmonary infiltrates, and encephalopathy developed. The patient first presented with a history of cat bites and scratches, fever, headache, and arthralgias. Four weeks later, the clinical presentation of septic shock suddenly developed in the patient. Cat-scratch disease was documented clinically and by finding delicate pleomorphic bacilli in Warthin-Starry silver stains of biopsy specimens taken from the primary inoculation site and regional lymph node. The administration of intravenous sulfamethoxazole and trimethoprim, erythromycin lactobionate, and tobramycin sulfate therapy correlated with recovery. Although cat-scratch disease is usually a benign, self-limited illness, this article illustrates its systemic nature, its potential for devastating complications in the immunocompromised host, and its possible response to vigorous antibiotic therapy.

Studies on pathogenesis of buffalo pox virus in rabbits: quantitative assay of virus in different organs.

The buffalo pox virus was found to multiply in the skin, the primary site of inoculation with an eclipse phase of 12 hr. The virus was then detected in the skin after 15 hr followed by its appearance in regional lymph nodes 36 hr postinoculation. Primary viremia was detected 48 hr postinoculation, followed by detection of virus in the lungs, liver, and spleen. The virus multiplied in the lungs on day 4 and in the liver and spleen on day 5 postinoculation and its release led to secondary viremia. In a follow-up from day 7 to 14 postinoculation, the virus was detected in the kidneys, stomach, intestines, and gonads.

Cat-Scratch Disease

Cat-scratch disease is a zoonotic infection characterized by a skin papule at the site of the scratch followed by regional lymphadenitis. Recently, small gram-negative pleomorphic bacilli were demonstrated in sections of lymph node from patients with the disease. We now report identical bacteria in the primary inoculation site of three patients with cat-scratch disease. Lymph nodes from two of these patients also contained the same bacilli. Identical bacteria in both skin and lymph nodes from these patients are further evidence that the bacilli are the cause of cat-scratch disease. In early infections, biopsy of the primary site of inoculation and demonstration of bacilli may replace excision and histologic examination of lymph node in establishing the diagnosis of cat-scratch disease. (<i>JAMA</i>1984;252:928-931)

Antibodies to plasminogen activator inhibit human tumor metastasis

The human carcinoma HEp3 grows on the chorioallantoic membrane and metastasizes to the chicken embryo with kinetics that are quantitatively predictable. We have used this experimental system to test whether plasminogen activator produced by the tumor is required for metastasis. Rabbit antibodies were raised against human urinary urokinase; these cross-reacted with and blocked the catalytic activity of HEp3-PA but did not inhibit chicken PA. When administered intravenously to embryos that had received an inoculum of HEp3 cells, the anti-urokinase antibodies did not inhibit tumor growth at the site of primary inoculation on the chorioallantoic membrane, but they either prevented or strongly inhibited metastasis to the embryo lung. Antibody treatment delayed the onset of pulmonary metastasis, indicating that plasminogen activator is required during early stages of the process.

Lymphatic invasion and metastasis

The phenomenon of experimental lymphatic invasion and metastasis has been reviewed. The invasion of lymphatics must be dependent on the same factors as are involved in neoplastic invasion in generalcell motility, lack of adhesiveness, release of lytic enzymes, increase in cell population and tissue pressure and active migration of cells. The process of lymphatic metastasis consists of a) penetration of the peripheral lymphatic wall, b) embolism lodgement and growth in the draining lymph node. The study of lymphatic metastasis in experimental animals requires precise and defined models. It seems in the only model studied that initial penetration occurs by reverse diapedesis of tumor cells through open interendothelial junctions. It seems at present that lymphocytes and macrophages migrate into lymphatic vessels in a similar way. It is likely but not certain that in some way the cells induce opening of lymphatic endothelial junctions. Whether this process is specific or non-specific and whether it involves release of chemical mediators is uncertain. There is some evidence that in one model there is induction selection of one tumor subtype for successful metastasis, though it is far from certain that this is universally true. The cellular reactions in the draining lymph node include sinus macrophage proliferation, proliferation of cells in germinal centres, and migration of cells from post capillary-venules. A definable burden of tumor cells in the node is necessary for successful metastasis; this burden is much smaller than that necessary for growth in the primary inoculation site, indicating a degree of immunological privilege within the node. A lymphoreticular and therefore presumably immunological reaction in either primary injection site or node may result in tumor rejection. The influence of the lymph node on the process of metastasis is dubious. Lymph nodes are probably not effective barriers against tumor. There is much controversy both on the effect of the lymphoreticular response (enhancing or retarding growth) as well as on the effect of regional lymph node removal. While the 2 major methods of dissemination of neoplasm by blood and by lymph are closely related there may be differences in sensitivity to chemotherapy; in one model lymph node metastases have been shown to be more sensitive to chemotherapy. There is a great need for experimental work on lymphatic metastasis to provide guidelines for new approaches to the treatment, and even prevention of metastasis in human cancer.

Studies on the Mechanisms of Resistance in the Rice Plants Infected with Xanthomonas oryzae

Induction of resistance was studied in rice plant-Xanthomonas oryzae system by inoculating leaves primarily with incompatible strain or nonpathogen and challenging with a compatible strain. Lesion enlargement was markedly inhibited by the preliminary inoculation with incompatible strains of X. oryzae, but not with compatible strains. Inhibition was higher in the region located closer to the site of primary inoculation and was significant even in the tissue located 5cm apart from the site of primary interaction. Inhibition was highest when challenge inoculation was made 3 days after inducer inoculation and was remained effective until 9 days after preinoculation. Among 14 species of nonpathogenic bacteria tested, P. phaseolicola, X. citri, P. marginalis, and C. michiganense were highest in their ability to induce resistance, followed by P. solanacearum, X. campestris, P. lachrymans, E. carotovora, and X. phaseoli. C. sepedonicum, P. tabaci and A. tumefaciens were able to induce a weak resistance and X. pruni and X. phaseoli f. sp. sojense did not induce any resistance. These nonpathogenic bacteria, however, did not induce detectable resistance in the region located more than 3cm from the site of inducing interaction and when challenge inoculation was made 6 or more days after the inducer inoculation. Among saprophytes tested, 2 contaminants isolated from culture plates of X. oryzae produced a clear inhibition zone on plating and were also capable of inducing resistance, but 3 others isolated from healthy rice leaves did not induce resistance. Preliminary results suggested that neither nutritional competition nor production of antibacterial substance by the primary bacteria seemed responsible for this type of induced resistance, at least not with X. citri and P. tabaci.

Sporotrichoid Nocardiosis Caused by Nocardia Brasiliensis

A 52-year-old white man accidently inoculated his finger with a contaminated thorn while clearing the roadside of "saw briar," Smilax tamnoides var. hispida. The organism spread from the primary inoculation site to form a chain of nodules up the back of the hand, wrist, and arm to simulate sporotrichosis. The fungus was isolated in culture and identified as Nocardia brasiliensis.

Mechanism of Infection in South American Blastomycosis

SummaryThe habitat of Paracoccidioides (Blastomyces) brasiliensis has not yet been established, but the source of in fection is probably exogenous. The clinical man ife stations and the course of the infection favor the digestive tract (mainly the oral mucosa) as the most common portal of en try of the fungus into the body. Although the lungs may also be a point of ingress, the author believes that pulmonary lesions are usually the result of hematogenous spread. It is extremely ra re for the skin to be the site of primary inoculation. The lymphatic route plays an important role in the dissemination of the infection to the various parts of the human body.