Genital infection of female hamsters with herpesvirus hominis type 2 (HVH-2).

Intravaginal inoculation of female hamsters (40-65 g) with HVH-2 (6 X 105 PFU) results in an infection of 40-67% of the animals. The illness is characterized by vaginitis with discharge, paralysis, and finally death. Washing the vagina with saline 30 min prior to virus inoculation enhances the infection so that 80-100% of the animals eventually die. Virus can be isolated from the vagina within 1-2 days after inoculation. Evidence of infection of the spinal cord is apparent by the third day whereas virus could not be isolated from the brain until Day 5. Attempts to demonstrate virus in whole blood, spleen, kidney, or liver homogenates prepared from infected animals were negative.     

Influence of the Size of Indigenous Rhizobial Populations on Establishment and Symbiotic Performance of Introduced Rhizobia on Field-Grown Legumes

Indigenous rhizobia in soil present a competition barrier to the establishment of inoculant strains, possibly leading to inoculation failure. In this study, we used the natural diversity of rhizobial species and numbers in our fields to define, in quantitative terms, the relationship between indigenous rhizobial populations and inoculation response. Eight standardized inoculation trials were conducted at five well-characterized field sites on the island of Maui, Hawaii. Soil rhizobial populations ranged from 0 to over 3.5 × 10⁴ g of soil^-1 for the different legumes used. At each site, no less than four but as many as seven legume species were planted from among the following: soybean (Glycine max), lima bean (Phaseolus lunatus), cowpea (Vigna unguiculata), bush bean (Phaseolus vulgaris), peanut (Arachis hypogaea), Leucaena leucocephala, tinga pea (Lathyrus tingeatus), alfalfa (Medicago sativa), and clover (Trifolium repens). Each legume was (i) inoculated with an equal mixture of three effective strains of homologous rhizobia, (ii) fertilized at high rates with urea, or (iii) left uninoculated. For soybeans, a nonnodulating isoline was used in all trials as the rhizobia-negative control. Inoculation increased economic yield for 22 of the 29 (76%) legume species-site combinations. While the yield increase was greater than 100 kg ha^-1 in all cases, in only 11 (38%) of the species-site combinations was the increase statistically significant (P ≤ 0.05). On average, inoculation increased yield by 62%. Soybean (G. max) responded to inoculation most frequently, while cowpea (V. unguiculata) failed to respond in all trials. Inoculation responses in the other legumes were site dependent. The response to inoculation and the competitive success of inoculant rhizobia were inversely related to numbers of indigenous rhizobia. As few as 50 rhizobia g of soil^-1 eliminated inoculation response. When fewer than 10 indigenous rhizobia g of soil^-1 were present, economic yield was significantly increased 85% of the time. Yield was significantly increased in only 6% of the observations when numbers of indigenous rhizobia were greater than 10 cells g of soil^-1. A significant response to N application, significant increases in nodule parameters, and greater than 50% nodule occupancy by inoculant rhizobia did not necessarily coincide with significant inoculation responses. No less than a doubling of nodule mass and 66% nodule occupancy by inoculant rhizobia were required to significantly increase the yield of inoculated crops over that of uninoculated crops. However, lack of an inoculation response was common even when inoculum strains occupied the majority of nodules. In these trials, the symbiotic yield of crops was, on average, only 88% of the maximum yield potential, as defined by the fertilizer N treatment. The difference between the yield of N-fertilized crops and that of N₂-fixing crops indicates a potential for improving inoculation technology, the N₂ fixation capacity of rhizobial strains, and the efficiency of symbiosis. In this study, we show that the probability of enhancing yield with existing inoculation technology decreases dramatically with increasing numbers of indigenous rhizobia.     

Growth and virulence of Candida albicans after oral inoculation in the chick with a monoflora of either Escherichia coli or Streptococcus faecalis

Balish, Edward (Syracuse University, Syracuse, N.Y.), and A. W. Phillips. Growth and virulence of Candida albicans after oral inoculation in the chick with a monoflora of either Escherichia coli or Streptococcus faecalis. J. Bacteriol. 91:1744-1749. 1966.-Bacterial protection against intestinal infection by Candida albicans was investigated in chicks with a monoflora of either Escherichia coli or Streptococcus faecalis. These animals were obtained by orally inoculating germ-free chicks (3 days old) with pure cultures of bacteria. Each bacterial species was established in large numbers in the gut of separate groups of animals within 24 hr of inoculation; these numbers were similar in chicks examined 34 days later, at which time all animals were killed. The numbers of bacteria from contents of the crop, small intestine, and ceca were similar in chicks with the E. coli monoflora. Comparable results were obtained in chicks with the S. faecalis monoflora, except for decreased numbers in the duodenum and jejunum. Some of the monoflora chicks (7 days old) were transferred into separate isolators, orally inoculated with C. albicans, and observed for 34 days. All chicks grew well and appeared healthy. However, examinations at autopsy revealed severe crop infections in chicks with a diflora containing S. faecalis. Preferential growth of hyphae (C. albicans) occurred in the lesions and throughout the gut. The numbers of S. faecalis in the gut were comparable to those found in unchallenged animals. Agglutinins against C. albicans were not detected in our test or control chicks. Chicks with a diflora containing E. coli and C. albicans had a few microscopic crop lesions containing small numbers of hyphae. C. albicans was well established in the gut of these animals, largely as the yeast form. The numbers of E. coli in the gut were similar to those in control chicks. Thus, it was concluded that E. coli provided protection against crop infection by C. albicans. In crop contents from unchallenged animals, chicks with S. faecalis monoflora were about pH 5, whereas birds with E. coli monoflora were about pH 7. The challenge did not greatly change the former value, and the latter was slightly decreased. In the crop of unchallenged birds, negative E(h) values were found in chicks with S. faecalis and positive E(h) values in those with E. coli. Challenge did not greatly change these values. These data on pH and E(h) were related to conditions for morphogenesis of C. albicans and virulence. No major difference in the concentrations of serum proteins was seen in chicks with E. coli or S. faecalis after challenge with C. albicans. Possible mechanisms of the protective effect of E. coli are discussed.     

巨细胞病毒感染对新生豚鼠胸腺的影响

新生豚鼠皮下接种豚鼠巨细胞病毒(GPCMV)后,导致动物胸腺急性感染。感染豚鼠胸腺在接种后第五天开始出现病毒,第十天达高峰。此外,感染动物胸腺的发育受到抑制,细胞总数和T淋巴细胞数随朐腺中病毒滴度的增高而进行性下降,至接种GPCMV后第十天最显著。由于病毒对T细胞的作用,细胞表面红细胞受体的丧失导致胸腺Null细胞百分比高于对照动物。     

Tumor dormancy. I. Regression of BCL1 tumor and induction of a dormant tumor state in mice chimeric at the major histocompatibility complex

The growth of the BCL1 tumor in murine H-2 chimeras was studied. Lethally x-irradiated BALB/c mice were reconstituted with C57BL/6 bone marrow that had been depleted of T cells. When chimerism was established 90 to 120 days later, large doses of BCL1 cells were injected. The tumor grew progressively, reaching a peak level of as many as 10(9) tumor cells per animal by 40 days after inoculation. After that time, the tumor regressed in all the chimeric animals, and by 100 days after inoculation, virtually all the animals appeared disease free as judged by an absence of BCL1-idiotype-positive cells in the spleen and peripheral blood, a normal spleen size, and absence of an elevated white blood cell count. Such animals were followed for as long as 8 mo after tumor inoculation and remained disease free. However, transfer of graded numbers of splenocytes from these animals into normal BALB/c recipients resulted in development of tumor in recipients receiving 100 or more spleen cells. These results indicate a large tumor burden in the spleen of each donor, namely, 10(6) to 10(7) BCL1 cells. The present model should facilitate characterization of the mechanisms underlying tumor dormancy.     

Effect of Soybean Tip Removal on Penetration and Development of Heterodera glycines

On a few occasions, soybeans with broken root tips were included in tests to evaluate resistance to Heterodera glycines. Although females developed on these plants, the numbers tended to be lower than on similarly treated intact roots. To test the possibility that removal of the root meristem affected nematode development, a culture system using pruned soybeans was devised that permitted access to the roots without disturbing the plants. Treatments included removal of 2 mm of root tip at various times ranging from 24 hours before to 10 days after inoculation, or roots left intact. In each experiment, all roots were inoculated at the same time with equal numbers of freshly hatched second-stage juveniles of Heterodera glycines. No differences in nematode development were detected in plants with root tips removed after inoculation compared to the control. When tips were removed at or before inoculation, fewer juveniles entered roots and relatively fewer nematodes developed. Penetration levels and development correlated with root tip removal such that progressively fewer nematodes entered roots and relatively greater numbers of nematodes remained undeveloped as the time interval between root tip removal and inoculation was increased.     

Rapid, Direct Tissue Culture Test for Toxigenicity of Corynebacterium Diphtheriae

A method for testing toxigenicity of Corynebacterium diphtheriae in tissue culture is described. The technique, called the colony overlay test (COT), involves inoculating material from an isolated colony of C. diphtheriae to a small area on the surface of an agar medium which overlays a monolayer of toxin-susceptible HeLa cells. If toxin is produced during incubation at 37 C, it diffuses to the tissue monolayer and destroys the cells below the inoculation site. Twenty-four hours after inoculation, organisms are killed and tissue cells are fixed with formaldehyde. The agar overlay is then removed, and the monolayer is stained with crystal violet. Toxin-affected areas fail to stain or stain poorly. A second plate with antitoxin incorporated in the overlay serves as a control for specificity. Forty-eight strains of C. diphtheriae were tested by the COT, guinea pig, and in vitro, gel diffusion tests. The COT is as specific as the other two tests, is easy to read, and can be used to test large numbers of isolates for toxin action more conveniently than by animal inoculation.     

Differentiation of Two New York Isolates of Pratylenchus penetrans Based on Their Reaction on Potato

The behavior of two isolates of Pratylenchus penetrans on six potato clones was assessed to test the hypothesis that these nematode isolates from New York were different. Four potato cultivars (Superior, Russet Burbank, Butte, and Hudson) and two breeding lines (NY85 and L118-2) were inoculated with nematode isolates designated Cornell (CR) and Long Island (LI). Population increase and egression of nematodes from roots were used to distinguish resistance and susceptibility of the potato clones. Based on numbers of eggs, juveniles, and adults in their roots 30 days after inoculation, potato clones Butte, Hudson, and L118-2 were designated resistant to the CR isolate and susceptible to the LI isolate. More eggs were found in the roots of all plants inoculated with the LI isolate than with the CR isolate. The clones NY85 and L118-2 were inoculated with the CR and LI isolates in a 2 x 2 factorial experiment to assess differences in nematode egression. Egression was measured, beginning 3 days after inoculation, for 12 days. The rates of egression were similar for the four treatments and fit linear regression models, but differences were detected in numbers of egressed nematodes. More nematodes of the CR isolate than the LI isolate egressed from L118-2. Differences in egression of females was particularly significant and can be used as an alternative or supplement to reproduction tests to assess resistance in potato to P. penetrans and to distinguish variation in virulence.     

Value of combining the erythrocyte sedimentation rate test with tuberculin testing in the control of tuberculosis in baboons.

2 batches of baboon infected with tuberculosis were subjected to serial tests with human and bovine tuberculin, while erythrocyte sedimentation rates were estimated concurrently. In the very early stages most but not all reacted to human tuberculin while fewer responded to bovine material. After further development of the disease, tuberculin tests remained positive while sedimentation rates were raised by 10-30 mm per hour. By the time early spread had occurred response to tuberculin was absent but sedimentation rates tended to increase. Advanced cases always tuberculin negative but sedimentation rates were in excess of 50 mm per hour. Such animals were always in good physical condition and represented an insidious danger to other animals and staff in contact with them. Clinical examination failed to reveal cases of tuberculosis except in the terminal stages and no cases were diagnosed by radiography. 2 animals died from apparent anaphylaxis following inoculation of both types of tuberculin. Results showed that use of one or other of these tests alone would not have made possible the elimination of infection.     

Psychopharmacological profile of Chamomile (Matricaria recutita L.) essential oil in mice

In this study, the effect of Matricaria recutita L. essential oil (MEO) on the central nervous system (CNS) of mice was investigated using some behavioral methods. Chemical profiling both by GC and GC-MS analyses of the hydrodistilled essential oil of M. recutita revealed α-bisabolol oxide A (28%), α-bisabolol oxide B (17.1%), (Z)-β-Farnesene (15.9%) and α-bisabolol (6.8%) as the main components. Changes induced by MEO (25, 50 and 100 mg/kg) and reference drug caffeine (25 mg/kg) in spontaneous locomotor activities and motor coordinations of mice were investigated by activity cage measurements and Rota-Rod tests, respectively. Open field, social interaction and elevated plus-maze tests were applied to assess the emotional state of the animals. Further, tail-suspension test was performed for evaluating the effect of MEO on depression levels of mice. As a result, at 50 and 100 mg/kg, MEO significantly increased the numbers of spontaneous locomotor activities, exhibited anxiogenic effect in the open field, elevated plus-maze and social interaction tests and decreased the immobility times of animals in tail suspension tests. The falling latencies in Rota-Rod tests did not change. This activity profile of MEO was similar to the typical psychostimulant caffeine. The exact mechanism of action underlying this stimulant-like effect should be clarified with further detailed studies.     

Infection-induced coronary dysfunction and systemic inflammation in piglets are dampened in hypercholesterolemic milieu

The synergism of infection with conventional cardiovascular risk factors in atherosclerosis is much debated. We hypothesized that coronary arterial injury correlates with infection recurrence and pathogen burden and is further aggravated by hypercholesterolemia. Forty-two G?ttingen minipigs were assigned to repeated intratracheal inoculation of PBS, Chlamydia pneumoniae (Cpn), or both Cpn and influenza virus at 8, 11, and 14 wk of age. Animals were fed either standard or 2% cholesterol diet (chol-diet). At 19 wk of age coronary vasomotor responses to acetylcholine (ACh) and adenosine were assessed in vivo and blood and tissue samples were collected. Nonparametric tests were used to compare the groups. In cholesterol-fed animals, total cholesterol/HDL was significantly increased in infected animals compared with noninfected animals [3.13 (2.17-3.38) vs. 2.03 (1.53-2.41), respectively; P = 0.01]. C-reactive protein (CRP) rose in infected animals [10.60 (4.96-18.00) vs. 2.47 (1.44-3.01) μg/ml in noninfected; P < 0.01] without significant difference between the mono- and coinfected groups. Among coinfected animals, both CRP and haptoglobin were lower in those fed chol-diet than in those fed standard diet (P < 0.05). The vasoconstricting response to ACh was most prominent in coinfected animals {769.3 (594-1,129) cm; P = 0.03 vs. noninfected [342 (309-455) cm] and P = 0.07 vs. monoinfected [415 (252.5-971.8) cm]}. Among monoinfected animals, similar to CRP, a trend for less vasoconstriction was observed in those fed chol-diet (P = 0.08). Coinfection of piglets appears to be associated with more pronounced coronary muscarinic vasomotor dysfunction. In monoinfected animals, use of chol-diet seems to dampen both coronary dysfunction and systemic inflammation induced by infection.     

Experimental coinfection of rhesus macaques with rhesus cytomegalovirus and simian immunodeficiency virus: pathogenesis

Human cytomegalovirus (HCMV) possesses low pathogenic potential in an immunocompetent host. In the immunosuppressed host, however, a wide spectrum of infection outcomes, ranging from asymptomatic to life threatening, can follow either primary or nonprimary infection. The variability in the manifestations of HCMV infection in immunosuppressed individuals implies that there is a threshold of host antiviral immunity that can effectively limit disease potential. We used a nonhuman primate model of CMV infection to assess the relationship between CMV disease and the levels of developing anti-CMV immunity. Naive rhesus macaques were inoculated with rhesus cytomegalovirus (RhCMV) followed 2 or 11 weeks later by inoculation with pathogenic simian immunodeficiency virus SIVmac239. Two of four monkeys inoculated with SIV at 2 weeks after inoculation with RhCMV died within 11 weeks with simian AIDS (SAIDS), including activated RhCMV infection. Neither animal had detectable anti-SIV antibodies. The other two animals died 17 and 27 weeks after SIV inoculation with either SAIDS or early lymphoid depletion, although no histological evidence of activated RhCMV was observed. Both had weak anti-SIV antibody titers. RhCMV antibody responses for this group of monkeys were significantly below those of control animals inoculated with only RhCMV. In addition, all animals of this group had persistent RhCMV DNA in plasma and high copy numbers of RhCMV in tissues. In contrast, animals that were inoculated with SIV at 11 weeks after RhCMV infection rarely exhibited RhCMV DNA in plasma, had low copy numbers of RhCMV DNA in most tissues, and did not develop early onset of SAIDS or activated RhCMV. SIV antibody titers were mostly robust and sustained in these monkeys. SIV inoculation blunted further development of RhCMV humoral responses, unlike the normal pattern of development in control monkeys following RhCMV inoculation. Anti-RhCMV immunoglobulin G levels and avidity were slightly below control values, but levels maintained were higher than those observed following SIV infection at 2 weeks after RhCMV inoculation. These findings demonstrate that SIV produces long-lasting insults to the humoral immune system beginning very early after SIV infection. The results also indicate that anti-RhCMV immune development at 11 weeks after infection was sufficient to protect the host from acute RhCMV sequelae following SIV infection, in contrast to the lack of protection afforded by only 2 weeks of immune response to RhCMV. As previously observed, monkeys that were not able to mount a significant immune response to SIV were the most susceptible to SAIDS, including activated RhCMV infection. Rapid development of SAIDS in animals inoculated with SIV 2 weeks after RhCMV inoculation suggests that RhCMV can augment SIV pathogenesis, particularly during primary infection by both viruses.     

Serum glycoproteins in rats with experimental coccidioidomycosis

Summary The changes in the serum glycoproteins and the development of specific antibodies were examined during the course of experimental coccidioidomycosis in rats. The total glycoprotein, seromucoid hexose, seromucoid protein, and haptoglobin levels were signigicantly higher in sera from infected animals compared with sera from non-infected controls. These changes were evident at three days but not at two weeks following inoculation withC. immitis. The non-seromucoid hexose and total protein concentrations were not significantly different between infected animals and controls. The highest percentages of animals exhibiting positive tests for complement fixing and precipitin antibodies and positive cultures forC. immitis in organs at autopsy were found one week after infection.This study was supported in part by USPHS Grants T1 A1 52-07, A106048-02 and the Dermatologic Research Foundation of California, Inc.     

Diagnosis of encephalitozoonosis in experimentally infected rabbits by intradermal and immunofluorescence tests.

The indirect immunofluorescence antibody test was performed on serial blood samples from eight young New Zealand White rabbits with experimental encephalitozoonosis. The test showed seroconversion in six of the eight infected rabbits by the 8th day after inoculation and in all rabbits by the 15th day. Antibody titers reached a peak by about the 36th day after inoculation and remained significantly elevated until the termination of the experiment at 84 days after inoculation. None of four sham-inoculated rabbits showed an immunofluorescence response by the 60th day after inoculation. Immunofluorescence and intradermal test responses were compared before infection and at the 60th day after inoculation in a total of 32 experimentally infected rabbits. Both tests were equally effective (100%) in detecting infected animals. Six of eight (first group) and 22 of 24 (second group) experimentally infected rabbits were confirmed histologically to have lesions compatible with encephalitozoonosis. No cross reactions were observed between Encephalitozoon cuniculi and Toxoplasma gondii, Eimeria perforans, or Eimeria stiedai by intradermal test or immunofluorescence test.     

The efficacy of tetracyclines in peripheral and intracerebral prion infection

We have previously shown that tetracyclines interact with and reverse the protease resistance of pathological prion protein extracted from scrapie-infected animals and patients with all forms of Creutzfeldt-Jakob disease, lowering the prion titre and prolonging survival of cerebrally infected animals. To investigate the effectiveness of these drugs as anti-prion agents Syrian hamsters were inoculated intramuscularly or subcutaneously with 263K scrapie strain at a 10(-4) dilution. Tetracyclines were injected intramuscularly or intraperitoneally at the dose of 10 mg/kg. A single intramuscular dose of doxycycline one hour after infection in the same site of inoculation prolonged median survival by 64%. Intraperitoneal doses of tetracyclines every two days for 40 or 44 days increased survival time by 25% (doxycycline), 32% (tetracycline); and 81% (minocycline) after intramuscular infection, and 35% (doxycycline) after subcutaneous infection. To extend the therapeutic potential of tetracyclines, we investigated the efficacy of direct infusion of tetracyclines in advanced infection. Since intracerebroventricular infusion of tetracycline solutions can cause overt acute toxicity in animals, we entrapped the drugs in liposomes. Animals were inoculated intracerebrally with a 10(-4) dilution of the 263K scrapie strain. A single intracerebroventricular infusion of 25 microg/20 microl of doxycycline or minocycline entrapped in liposomes was administered 60 days after inoculation, when 50% of animals showed initial symptoms of the disease. Median survival increased of 8.1% with doxycycline and 10% with minocycline. These data suggest that tetracyclines might have therapeutic potential for humans.     

Dual role of polymorphonuclear neutrophils on the growth of Ehrlich ascites tumor (EAT) in mice

We show that granulocytes (PMN) have a dual role in the development of Ehrlich Ascites Tumor (EAT) in mice. EAT intraperitoneal inoculation causes a local inflammatory reaction, ascites development and mortality that distinguish resistant and susceptible strains. In resistant mice (CAF1), there is a less pronounced PMN influx after EAT inoculation than in susceptible Swiss mice. Accordingly, the increase in peritoneal PMN numbers enhanced tumor growth in CAF1 mice, but had no effect in the susceptible Swiss animals. Contrastingly, PMN depletion had no effect in resistant mice but facilitated tumor growth in susceptible animals. Though no differences were noted between the strains in peritoneal cell spreading and hydrogen peroxide release after tumor inoculation, in vitro PMN cytotoxic activity against EAT was significantly higher in susceptible Swiss mice. These data indicate a paradoxical dual role for PMN against EAT: while they help control tumor development in susceptible animals, they seem to enhance tumor growth in resistant mice.     

Validity of Spinal Cord Examination as a Substitute Procedure for Routine Rabies Diagnosis

A significant portion of specimens received by this laboratory for rabies diagnosis is unsatisfactory for testing due to decomposition of the brain, or severe mutilation of the head when the animal was killed. Examination of the spinal cord was therefore explored as a possible alternative method when standard brain examination was not possible. In this study, both brain and spinal cord of 248 rabies-suspect animals were examined to assess the reliability of the spinal cord method. Brain and spinal cord of the 248 animals were examined by fluorescent antibody (FA) method, and mouse inoculation tests were performed on 247 brain specimens and 13 spinal cord specimens. By using both brain and spinal cord, 30 animals representing 8 species were diagnosed as rabid by FA, and 218, representing 11 species, were negative. There was 100% agreement between two procedures with FA as the criterion. This study showed that in cases where the usual examination is precluded due to brain destruction, the spinal cord procedure offers an equally reliable alternate method of diagnosis.     

Recovery of adult stages and microfilaraemia after low dose inoculation of third stage larvae of Litomosoides carinii in Sigmodon hispidus

Because of the negative binomial distribution of filarial third stage larvae (L3) in their vectors, under natural conditions only a few are usually transferred per bite. After an inoculation of 5 L3 per animal into eight host animals at least one developed a long lasting patency based on one reproductive female only. After an inoculation of 15 L3, three of eight animals developed long lasting patency, harbouring between two and five fertile females. The rates of adult stages recovered were 0.43 and 0.30 respectively. The parasitaemias of the six patent animals in both experimental groups increased with the number of reproductive females present (r = 0.89, p = less than 0.005). All non-patent animals which were mf-negative in the pleural fluid and lung blood as well had a single sex or no worm load. In only one animal was there an apparently normal but non-reproductive pair of worms without any pathological alterations of the host animal. Encapsulated adult worms were found rarely, but independent of the final worm load or inoculation dose and always beside normal adults. In three of the 16 animals inoculated with 5 or 15 L3 patency passed after 10-12 weeks p.i., in two others it seemed to pass soon. After inoculation of 30, 40 or 60 L3 per animal patency passed early in about one half of 105 animals, when they were observed up to 24-36 weeks p.i. In conclusion all types of host defensive reactions are already visible after inoculation with such small doses.(ABSTRACT TRUNCATED AT 250 WORDS)