The Structure of the Human Respiratory Syncytial Virus M2-1 Protein Bound to the Interaction Domain of the Phosphoprotein P Defines the Orientation of the Complex

Human respiratory syncytial virus (HRSV) is a negative-stranded RNA virus that causes a globally prevalent respiratory infection, which can cause life-threatening illness, particularly in the young, elderly, and immunocompromised. HRSV multiplication depends on replication and transcription of the HRSV genes by the virus-encoded RNA-dependent RNA polymerase (RdRp). For replication, this complex comprises the phosphoprotein (P) and the large protein (L), whereas for transcription, the M2-1 protein is also required. M2-1 is recruited to the RdRp by interaction with P and also interacts with RNA at overlapping binding sites on the M2-1 surface, such that binding of these partners is mutually exclusive. The molecular basis for the transcriptional requirement of M2-1 is unclear, as is the consequence of competition between P and RNA for M2-1 binding, which is likely a critical step in the transcription mechanism. Here, we report the crystal structure at 2.4 Å of M2-1 bound to the P interaction domain, which comprises P residues 90 to 110. The P90-110 peptide is alpha helical, and its position on the surface of M2-1 defines the orientation of the three transcriptase components within the complex. The M2-1/P interface includes ionic, hydrophobic, and hydrogen bond interactions, and the critical contribution of these contacts to complex formation was assessed using a minigenome assay. The affinity of M2-1 for RNA and P ligands was quantified using fluorescence anisotropy, which showed high-affinity RNAs could outcompete P. This has important implications for the mechanism of transcription, particularly the events surrounding transcription termination and synthesis of poly(A) sequences.IMPORTANCE Human respiratory syncytial virus (HRSV) is a leading cause of respiratory illness, particularly in the young, elderly, and immunocompromised, and has also been linked to the development of asthma. HRSV replication depends on P and L, whereas transcription also requires M2-1. M2-1 interacts with P and RNA at overlapping binding sites; while these interactions are necessary for transcriptional activity, the mechanism of M2-1 action is unclear. To better understand HRSV transcription, we solved the crystal structure of M2-1 in complex with the minimal P interaction domain, revealing molecular details of the M2-1/P interface and defining the orientation of M2-1 within the tripartite complex. The M2-1/P interaction is relatively weak, suggesting high-affinity RNAs may displace M2-1 from the complex, providing the basis for a new model describing the role of M2-1 in transcription. Recently, the small molecules quercetin and cyclopamine have been used to validate M2-1 as a drug target.

Contribution of the KSHV and EBV lytic cycles to tumourigenesis

Kaposi's Sarcoma-associated herpesvirus (KSHV) and Epstein Barr virus (EBV) are the causative agents of several malignancies. Like all herpesviruses, KSHV and EBV undergo distinct latent and lytic replication programmes. The transition between these states allows the establishment of a lifelong persistent infection, dissemination to sites of disease and the spread to new hosts. Latency-associated viral proteins have been well characterised in transformation and tumourigenesis pathways; however, a number of studies have shown that abrogation of KSHV and EBV lytic gene expression impairs the oncogenesis of several cancers. Furthermore, several lytically expressed proteins have been functionally tethered to the angioproliferative and anti-apoptotic phenotypes of virus-infected cells. As a result, the investigation and therapeutic targeting of KSHV and EBV lytic cycles may be essential for the treatment of their associated malignancies.

Human β-defensin-2 production upon viral and bacterial co-infection is attenuated in COPD

Viral-bacterial co-infections are associated with severe exacerbations of COPD. Epithelial antimicrobial peptides, including human β-defensin-2 (HBD-2), are integral to innate host defenses. In this study, we examined how co-infection of airway epithelial cells with rhinovirus and Pseudomonas aeruginosa modulates HBD-2 expression, and whether these responses are attenuated by cigarette smoke and in epithelial cells obtained by bronchial brushings from smokers with normal lung function or from COPD patients. When human airway epithelial cells from normal lungs were infected with rhinovirus, Pseudomonas aeruginosa, or the combination, co-infection with rhinovirus and bacteria resulted in synergistic induction of HBD-2 (p<0.05). The combination of virus and flagellin replicated this synergistic increase (p<0.05), and synergy was not seen using a flagella-deficient mutant Pseudomonas (p<0.05). The effects of Pseudomonas aeruginosa were mediated via interactions of flagellin with TLR5. The effects of HRV-16 depended upon viral replication but did not appear to be mediated via the intracellular RNA helicases, retinoic acid-inducible gene-I or melanoma differentiation-associated gene-5. Cigarette smoke extract significantly decreased HBD-2 production in response to co-infection. Attenuated production was also observed following co-infection of cells obtained from healthy smokers or COPD patients compared to healthy controls (p<0.05). We conclude that co-exposure to HRV-16 and Pseudomonas aeruginosa induces synergistic production of HBD-2 from epithelial cells and that this synergistic induction of HBD-2 is reduced in COPD patients. This may contribute to the more severe exacerbations these patients experience in response to viral-bacterial co-infections.

ST elevation on the exercise ECG in patients presenting with chest pain and no prior history of myocardial infarction

OBJECTIVE

To assess the aetiology, and prognosis of ST-segment elevation (STE) on the exercise electrocardiogram in patients with chest pain without a prior history of myocardial infarction (MI).

METHODS

Between January 1998 and December 2005, 14 941 exercise stress tests were performed to assess chest pain in patients without a prior history of MI. Those who developed STE were identified.

RESULTS

STE occurred in 0.78% (116/14 941). Coronary angiography was performed in 108 patients. All patients had at least one severe coronary artery stenosis (>70%). The site of STE on exercise ECG was shown to be 95.4% predictive of a severe stenosis in the coronary artery supplying that area. Lateral STE was rare (1/116). Ninety-eight patients underwent revascularisation; 67 patients had percutaneous coronary intervention (PCI) and 31 underwent coronary artery bypass grafting (CABG). Follow-up included recording of death, MI, cerebrovascular event, heart failure and target vessel revascularisation. The projected 7-year event-free survival probability was 62.1% for those undergoing CABG, 77.1% for those who had PCI and 68.6% for those not undergoing revascularisation (no difference between these three groups, log rank p = 0.802).

CONCLUSIONS

STE on the exercise ECG is rare but specific for ischaemic heart disease and is predictive of a severe stenosis in the corresponding coronary artery. Prognosis is favourable following revascularisation.

Hepatobiliary inflammation, neoplasia, and argyrophilic bacteria in a ferret colony

Hepatobiliary disease was diagnosed in eight of 34 genetically unrelated cohabitating pet ferrets (Mustela putorios furo) during a 7-year period. The eight ferrets ranged in age from 5 to 8 years and exhibited chronic cholangiohepatitis coupled with cellular proliferation ranging from hyperplasia to frank neoplasia. Spiral-shaped argyrophilic bacteria were demonstrated in livers of three ferrets, including two with carcinoma. Sequence analysis of a 400-base pair polymerase chain reaction product amplified from DNA derived from fecal bacteria from one ferret demonstrated 98% and 97% similarity to Helicobacter cholecystus and Helicobacter sp. strain 266-1 , respectively. The clustering of severe hepatic disease in these cohabitating ferroes suggests a possible infectious etiology. The role of Helicobacter species and other bacteria in hepatitis and/or neoplasia in ferrets requires further study.

Development of an effective gene delivery system: a study of complexes composed of a peptide-based amphiphilic DNA compaction agent and phospholipid

We recently described a basic technology to efficiently combine compacted DNA with phospholipids and hydrophobic peptides, to produce homogenous complexes that are completely resistant to nuclease. We have developed this technology further to form gene delivery complexes that transfect cells effectively in vitro. In addition to plasmid DNA, the complexes contained two basic components: (i) a DNA compacting peptide (-CGKKKFKLKH), either conjugated to lipid or extended to contain (WLPLPWGW-) and (ii) either phosphatidylethanolamine or phosphatidylcholine. Complexes containing a 5.5-fold charge equivalence (peptide charge/DNA charge) of WLPLPWGWCGKKKFKLKH and 5 nmol dimyristoleoylphosphatidylethanolamine/microg DNA produced the highest luciferase gene expression, exceeding 1 x 10(9) relative light units/s/mg protein (>3 microg luciferase per mg protein). These complexes transfected OVCAR-3, COS-7 and HeLa cells at either similar or superior levels when compared to polyethylenimine or lipofectamine complexes. With green fluorescent protein reporter gene, >50% of HeLa cells were positive 30 h after addition of these complexes. Furthermore, these optimal complexes were the least sensitive to pre-treatment of cells with chloroquine, indicating efficient endosomal escape. Our results indicated that self-assembling complexes of plasmid DNA, amphiphilic peptide and phosphatidylethanolamine are highly effective non-viral gene delivery systems.

RNA isolation and fractionation with compaction agents

A new approach to the isolation of RNA from bacterial lysates employs selective precipitation by compaction agents, such as hexammine cobalt and spermidine. Using 3.5 mM hexammine cobalt, total RNA can be selectively precipitated from a cell lysate. At a concentration of 2 mM hexammine cobalt, rRNA can be fractionated from low molecular weight RNA. The resulting RNA mixture is readily resolved to pure 5S and mixed 16S/23S rRNA by nondenaturing anion-exchange chromatography. Using a second stage of precipitation at 8 mM hexammine cobalt, the low molecular weight RNA fraction can be isolated by precipitation. Compaction precipitation was also applied to the purification of an artificial stable RNA derived from Escherichia coli 5S rRNA and to the isolation of an Escherichia coli-expressed ribozyme.

Optimization of a peptide/non-cationic lipid gene delivery system for effective microinjection into chicken embryo in vivo

Here we report the characterization and optimization of a peptide/non-cationic lipid gene delivery system that successfully produces high levels of gene expression when delivered by microinjection into chicken embryos in vivo. In addition to plasmid DNA, the delivery complex consisted of four components: 1) a "condensing" peptide with both hydrophobic and cationic amino acid segments; 2) a "fusogenic" peptide with both membrane insertion and amphipathic helical segments; 3) a relatively short-chain phosphatidylcholine (14:1 cis-9); and 4) polyethyleneglycol conjugated to dioleoylphosphatidylethanolamine through a disulfide linkage. Optimum amounts of each component were determined by measuring expression of a luciferase reporter gene following a 24-hour incubation with chick embryo fibroblast (CEF) cells in culture. When relatively low amounts of condensing peptide, fusogenic peptide, or lipid were assembled into the complexes, relatively large concentrations of complex were required to reach maximum gene expression. When the amounts of peptide or lipid were increased, less complex was required to achieve maximum expression, but expression fell substantially with higher amounts of added complex. The polyethyleneglycol component significantly increased gene expression. With some preparations, luciferase activities in the CEF cells reached 1x10(10) relative light units per second per mg protein within 24 hours. Following the optimization experiments with the CEF cells, formulations containing low levels, intermediate levels, and high levels of the delivery system components were assembled with green fluorescent protein plasmid DNA, then microinjected into somite regions of chicken embryos in vivo. It was found that intermediate levels of the components gave the most reliable formulations for inducing localized gene expression in the somitic cells.

Gastric dilatation syndrome associated with chronic nephropathy, hypergastrinemia, and gastritis in mice exposed to high levels of environmental antigens

Gastric dilatation (GD) has been observed in Tac:(SW)fBR surveillance mice, with mean age of 10 months, that are exposed to high levels of environmental antigens during routine exposure to dirty bedding. The aim of the study reported here was to determine whether GD was associated with other systemic conditions affecting mice. Three groups of nine animals including-surveillance mice not exposed to dirty bedding (control), surveillance mice with out GD (NGD), and surveillance mice with GD (group GD)-had mean stomach weight with ingesta of 0.5 +/- 0.02 g, 1.09 +/- 0.07 g (P < 0.0001), and 2.54 +/- 0.4 g (P < 0.0001), respectively. Mean serum creatinine concentration was significantly higher in GD (1.6 +/- 0.25 mg/dl), compared with NGD (0.17 +/- 0.22 mg/dl, P < 0.0001) and control (0.2 +/- 0.16 mg/ dl, P < 0.0001) mice. In addition, lesions consistent with severe chronic nephropathy and mild gastritis were common in GD, compared with NGD and control mice. Finally, serum amidated gastrin concentration was significantly high in GD (179.37 +/- 53.86 pM, P < 0.03) and NGD (264.89 +/- 115.89 pM, P < 0.009), compared with control (60.77 +/- 8.39 pM) mice. Gastric dilatation syndrome is associated with chronic nephropathy, hypergastrinemia, and gastritis in surveillance mice exposed to high levels of environmental antigens.

Term delivery following conservative treatment for villoglandular papillary adenocarcinoma of the uterine cervix: report of a case and analysis of the literature

BACKGROUND

Villoglandularpapillary adenocarcinoma (VPA) of the cervix is often indolent, and surgical treatment has a favorable outlook. Risk factors include depth of invasion, lymphovascular invasion, and the presence of other histologic types of cancer.

CASE

An amputation of the cervical portio was required to satisfactorily resect a 2.5-cm ectocervical lesion in a 28-year-old nulligravida. A diagnosis of pure VPA with a depth of invasion less than 2 mm was established. During a subsequent pregnancy, second trimester ultrasound showed extreme effacement of her cervix and an abdominal cerclage was placed. The pregnancy continued until delivery of a healthy infant at 36 weeks.

CONCLUSIONS

In cases of tumor invasion less than 3 mm, and in the absence of lymphovascular space involvement, extrauterine spread of pure VPA has not been described. When conservative treatment is planned, amputation of the cervical portio may be better suited than conization to the achievement of an adequate margin of resection. Cervical cerclage may be needed to offset the extensive cervical surgery.

Effects of general, special, and specific resistance training on throwing velocity in baseball: a brief review

Throwing velocity is a necessary requirement for success in baseball. All position players, including pitchers, may increase their defensive performance if their throwing velocity is improved. A review of the literature suggests that throwing velocity can be increased by resistance training and/or biomechanical improvement of the throwing motion. This paper reviews the 3 broad categories of resistance-training methods by which throwing velocity is increased. The results of research using general, special, and specific throwing resistance-training exercises are presented. The role and applications of these different exercises for baseball players of different ages are discussed.

Bypassing immunization: optimized design of "designer T cells" against carcinoembryonic antigen (CEA)-expressing tumors, and lack of suppression by soluble CEA

Tumor-associated antigens are typically nonimmunogenic in cancer patients, "immune surveillance" having manifestly failed. The fact that most tumor antigens are normal human proteins presents significant obstacles to current cancer immunization approaches that researchers are presently striving to overcome. An alternative strategy bypasses immunization altogether by direct genetic alteration of autologous patient T cells, to create "designer T cells" specific to a particular antigen. Chimeric immunoglobulin-T cell receptors (IgTCR) with a specificity for carcinoembryonic antigen (CEA) were created to evaluate the optimal IgTCR structure for cancer therapy. Antigen-binding domains of a humanized antibody were combined with TCR signaling chains to yield four different chimeric IgTCR: single chain Fv fragment (sFv)-zeta, fragment antigen-binding (Fab)-zeta, sFv-epsilon, and Fab-epsilon. All of the IgTCR were well expressed on T cells, and all showed specific binding and activation, as demonstrated by IL-2 production on contact with immobilized or cellular CEA, excepting sFv-epsilon alone which was inert solely against cellular targets for steric reasons unique to this construct. In contrast to prior studies of isolated TCR chains that related increased tyrosine-based activation motifs in zeta as a reason for superior signaling potency, these tests are the first to show that epsilon and zeta are indistinguishable for T cell signaling when assayed in the context of the intact TCR complex. Further, Fab was equivalent to sFv as an IgTCR component for expression and antigen binding, establishing an important alternative for IgTCR antigen recognition because sFvs may often lose antigen affinity. When IgTCR was expressed on normal human T cells, cytotoxic potency was demonstrated at low E:T ratios, with T cell recycling and progressive tumor cell destruction. Contrary to recent speculations, these observations prove that high affinity TCR interactions are not an impediment to serial target engagement and disengagement by cytotoxic T cells. The multivalent intercellular interactions of target cell binding, activation, and cytotoxicity were resistant to inhibition by soluble CEA. These studies establish a potentially important new immunotherapeutic modality for the treatment of CEA-expressing tumors.

Purification of plasmid DNA using selective precipitation by compaction agents

A scaleable method for the liquid-phase separation of plasmid DNA from RNA.

Pregnancy toxemia in the European ferret (Mustela putorius furo)

BACKGROUND AND OBJECTIVE

Pregnancy toxemia may lead to appreciable mortality among jills and their offspring. The objective of this report was to increase awareness of the disease, its likely cause, and practical prevention and treatment measures.

METHODS

Ten cases of pregnancy toxemia were evaluated. Jills were in late gestation (mean, 38 days; range, 34 to 42 days) and had large litters (mean, 11.5 kits; range, 7 to 15 kits).

RESULTS

The most common clinical signs of disease were lethargy, inappetence, dehydration, and excess shedding. Hematologic and clinical biochemical abnormalities included anemia (4 of 8 jills tested), hypoproteinemia (5 of 7), azotemia (7 of 7), hypocalcemia (5 of 6), hyperbilirubinemia (3 of 3), and high liver enzyme activities (6 of 6). Two jills were found dead; two jills were euthanized, six received supportive treatment, and cesarean section was performed on five. The three jills that survived tended to have less pronounced azotemia, hypoproteinemia, and liver enzyme activity increases and were not anemic. Hepatic lipidosis was observed grossly in all jills that died and was confirmed by histologic examination in four jills.

CONCLUSIONS

Pregnancy toxemia in ferrets resembles metabolic diseases in several other animal species and requires aggressive treatment, including supportive care, nutritional supplementation, and cesarean section. Maintaining adequate nutrition and avoiding stress late in gestation may prevent the disease.

A single-chain immunotoxin against carcinoembryonic antigen that suppresses growth of colorectal carcinoma cells

We have engineered an anti-carcinoembryonic antigen (CEA) single-chain immunotoxin derived from humanized anti-CEA antibody (hMN14) and a truncated Pseudomonas exotoxin (PE), PE40. The purified anti-CEA immunotoxin (hMN14(Fv)-PE40) was first measured for binding affinity against a CEA-positive colorectal carcinoma cell line and compared with its parental IgG and the monovalent Fab fragment. The Ka of sFv-PE40, Fab, and IgG were 5 x 10(7), 6 x 10(7), and 3 x 10(8) M(-1), respectively. There was no significant affinity loss by conversion of Fab to the single-chain Fv, but these monovalent forms were 5-6-fold reduced in affinity compared with the parental IgG. In cytotoxicity assays, the hMN14(Fv)-PE40 showed specific growth suppression of CEA-expressing colon cancer cell lines MIP-CEA (high CEA) and LS174T (moderate CEA) with IC50s of 12 ng/ml (0.2 nM) and 69 ng/ml (1.1 nM). These IC50s correlated inversely with the surface expression of CEA, such that 50% killing was equivalent for each cell type when expressed in toxin molecules bound/cell (3000-5000). The presence of soluble CEA up to 1000 ng/ml did not affect the cytotoxicity against CEA-expressing cells, with 50% suppression only at 4000 ng/ml that correlated with the binding Kd of the single-chain Fv. The stability of the hMN14(Fv)-PE40 molecule at 37 degrees C was confirmed by bioassay and by lack of aggregation. Our hMN14(Fv)-PE40 may be clinically useful for tumors with high CEA expression without affecting normal tissues with low or absent CEA, even in patients with high soluble antigen levels.

Spontaneous inflammatory bowel disease in multiple mutant mouse lines: association with colonization by Helicobacter hepaticus

BACKGROUND

Both genetic and microbial factors are thought to play a role in the development of inflammatory bowel disease (IBD): however, no causative microbial agent has been clearly defined for humans or animals. Normal flora or previously unrecognized intestinal pathogens may contribute to the development of disease in susceptible hosts. A newly recognized murine Helicobacter, H. hepaticus, causes hepatitis in mice and in one strain of mice is linked to liver cancer. This study investigates the association between colonization of the lower intestinal tract of multiple genetically altered lines of mice with H. hepaticus, and the occurrence of IBD.

MATERIALS AND METHODS

Rectal prolapse noted clinically in multiple genetically altered mouse lines was evaluated for the presence of H. hepaticus and histologic evidence of IBD. Fifty-five mice representing 11 different genetic alterations were evaluated.

RESULTS

H. hepaticus was detected in 85% of mutant mice with rectal prolapse. Histologic evidence of proliferative typhlitis, colitis or proctitis was present in 65% of the animals examined, 89% of which were positive for H. hepaticus as detected by species specific PCR.

CONCLUSION

The presence of H. hepaticus in association with IBD in multiple lines of genetically altered mice suggests further studies are needed to test experimentally the role H. hepaticus plays in the development of IBD in susceptible mice. Additionally, specific mutant mouse lines infected with H. hepaticus in this study may provide additional models for elucidation of microbial and genetic factors in the pathogenesis of IBD.

Integration of an Internet anatomy review of the knee joint in a rehabilitation sciences curriculum: "http:/(/)www.musc.edu/chp-rehab/anatomy/ kneedemo.htm"

The cost and difficulty of obtaining cadavers to teach anatomy in allied health programs and in medical schools have led to the development of new interactive technology to complement cadaver dissection. However, the price of these computer software packages often limits the schools from purchasing these products. The advantages of the Internet in the academic setting (easy and global accessibility associated with low cost) enticed us to develop an Internet site to study the anatomy of the knee. This article describes the process of developing an Internet site, the procedure for accessing an Internet site, and the contribution of Internet sites to the teaching of anatomy to students. Finally, this article provides addresses on the Internet for other anatomy sites related to the anatomy of the knee. In conclusion, our Internet site allows the students to study anatomy at a low cost while utilizing a new and exciting educational medium.

Prognosis of dislocation after total hip arthroplasty

One hundred sixty-one dislocations after cemented total hip arthroplasty, with a mean follow-up period of 8 years after dislocation, were reviewed with the aim of establishing the prognosis. There were 84% single and 16% recurrent dislocations. Closed reduction was successful in 81% of cases. Thirty-seven percent of dislocations were early (within 5 weeks), 36% occurred in patients who had had previous surgery, and in 47% there was nonunion of the trochanter. There was a two-way interaction between these factors, and all factors were significant for recurrent dislocation. Twenty-six (16%) recurrent dislocations required surgery. The most common causes of recurrent dislocation demonstrated at operation were component malposition (58%) and failure of the abductor mechanism (42%). In total, 96% of cases were successfully treated.

Total hip arthroplasty for congenital dysplasia or dislocation of the hip. Survivorship analysis and long-term results

Two hundred and thirty-two total hip replacements with cement were performed between 1965 and 1987 in 190 patients who had osteoarthrosis secondary to acetabular dysplasia resulting from congenital dysplasia or dislocation of the hip. Forty-nine patients (fifty hips) who died or who did not have at least three years of clinical and radiographic follow-up were excluded; therefore, the study comprised 141 patients (182 hips), 125 of whom were women and sixteen of whom were men. The mean age at the time of the operation was 42.5 years (range, 19.5 to 76.5 years), and the mean duration of follow-up was 9.9 years (range, 3.1 to 22.8 years). A Charnley low-friction prosthesis with a 22.25-millimeter femoral head was used in all hips. A trochanteric osteotomy was performed in 164 hips. A direct lateral approach was used only when there was a limb-length discrepancy of less than two centimeters. Bulk autogenous graft was not used to augment the fixation of the acetabular component. The hips were divided into two groups on the basis of the degree of subluxation or dislocation according to the classification of Crowe et al. One hundred and thirty-six hips were grade I, II, or III (indicating subluxation) (Group S), and forty-six hips were grade IV (indicating dislocation) (Group D). At the most recent follow-up evaluation, 128 (94 per cent) of the 136 hips in Group S and forty-four (96 per cent) of the forty-six hips in Group D caused no or only slight pain (a score of 6 or 5 points, respectively, according to the system of Merle d'Aubigné and Postel). Nineteen cups (10 per cent) and five stems (3 per cent) failed and were revised. The rate of revision for loosening of the femoral component in Group D (2 per cent [one stem]) was similar to that in Group S (3 per cent [four stems]). In comparison, the rate of revision of the acetabular component in Group D (15 per cent [seven cups]) was almost twice that in Group S (9 per cent [twelve cups]). This study demonstrated satisfactory clinical results at a mean of nearly ten years. The fixation of the femoral components appeared to be satisfactory; however, the failure of the fixation of the acetabular components in Group D (the dislocated hips) is a cause for concern.

Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide

BACKGROUND

The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response.

MATERIALS AND METHODS

Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated.

RESULTS

All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups.

CONCLUSIONS

Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.

Poloxamer 188 decreases susceptibility of artificial lipid membranes to electroporation

The effect of a nontoxic, nonionic block co-polymeric surface active agent, poloxamer 188, on electroporation of artificial lipid membranes made of azolectin, was investigated. Two different experimental protocols were used in our study: charge pulse and voltage clamp. For the charge pulse protocol, membranes were pulsed with a 10-micronsecond rectangular voltage waveform, after which membrane voltage decay was observed through an external 1-M omega resistance. For the voltage clamp protocol the membranes were pulsed with a waveform that consisted of an initial 10-microsecond rectangular phase, followed by a negative sloped ramp that decayed to zero in the subsequent 500 microseconds. Several parameters characterizing the electroporation process were measured and compared for the control membranes and membranes treated with 1.0 mM poloxamer 188. For both the charge pulse and voltage clamp experiments, the threshold voltage (amplitude of initial rectangular phase) and latency time (time elapsed between the end of rectangular phase and the onset of membrane electroporation) were measured. Membrane conductance (measured 200 microseconds after the initial rectangular phase) and rise time (tr; the time required for the porated membrane to reach a certain conductance value) were also determined for the voltage clamp experiments, and postelectroporation time constant (PE tau; the time constant for transmembrane voltage decay after onset of electroporation) for the charge pulse experiments. The charge pulse experiments were performed on 23 membranes with 10 control and 13 poloxamer-treated membranes, and voltage pulse experiments on 49 membranes with 26 control and 23 poloxamer-treated membranes. For both charge pulse and voltage clamp experiments, poloxamer 188-treated membranes exhibited a statistically higher threshold voltage (p = 0.1 and p = 0.06, respectively), and longer latency time (p = 0.04 and p = 0.05, respectively). Also, poloxamer 188-treated membranes were found to have a relatively lower conductance (p = 0.001), longer time required for the porated membrane to reach a certain conductance value (p = 0.05), and longer postelectroporation time constant (p = 0.005). Furthermore, addition of poloxamer 188 was found to reduce the membrane capacitance by approximately 4-8% in 5 min. These findings suggest that poloxamer 188 adsorbs into the lipid bilayers, thereby decreasing their susceptibility to electroporation.

Persistent hepatitis and enterocolitis in germfree mice infected with Helicobacter hepaticus

Helicobacter hepaticus has been associated with naturally occurring hepatitis in certain inbred strains of mice, and in A/JCr mice it has been linked to the development of hepatic adenomas and adenocarcinomas. H. hepaticus was orally inoculated into 30 axenic, outbred female mice, and the mice were studied longitudinally to fulfill Koch's postulates and to ascertain the pathogenic potential of the organism under defined germfree conditions. Ten cage contact mice were also housed in the same germfree isolator to study transmission patterns, and 10 germfree mice were maintained in separate isolators as controls. Mice serially euthanized from 3 weeks through 24 months postinoculation (p.i.) were surveyed by culture and PCR for H. hepaticus in liver and intestinal tissues. Tissues were analyzed for histopathological changes, and sera were assayed for the presence of immunoglobulin G antibody to H. hepaticus and changes in the liver enzyme alanine aminotransferase. Inoculated mice and cage contact mice were persistently infected with H. hepaticus as identified by culture and PCR, in both the intestine and, less frequently, the liver, for the duration of the 2-year study. Animals developed persistent chronic hepatitis, and in some animals enterocolitis was noted. Hepatocellular carcinoma was diagnosed in one H. hepaticus-infected mouse. The level of H. hepaticus serum antibody was highest in experimentally infected mice at 12 to 18 months p.i.; this corresponded in general to the time interval when the highest levels of alanine aminotransferase were recorded. Although cage contact mice became persistently infected with H. hepaticus, lesions were less severe and the levels of serological biomarkers utilized in the study were lower. The H. hepaticus-infected mouse will provide an ideal model to study putative bacterial virulence determinants and how they interact with the host to induce chronic inflammation and tumorigenesis.

Use of PCR and culture to detect Helicobacter pylori in naturally infected cats following triple antimicrobial therapy

Helicobacter pylori causes gastritis and peptic ulcers and is linked to gastric cancer. Domestic cats from a commercial source were found to be naturally infected with H. pylori, and studies were undertaken to eradicate H. pylori from infected cats by using triple antimicrobial therapy. Eight cats infected with H. pylori were used in the study. Six cats received a 21-day course of oral amoxicillin, metronidazole, and omeprazole, and two cats served as controls. Two weeks and 4 weeks posttreatment (p.t.), all six treated cats were negative at several sites (saliva, gastric juice, and gastric mucosa) for H. pylori by culture. However, as determined by PCR with primers specific for the 26-kDa product, the majority of cats at 2 and 4 weeks p.t. had gastric fluid samples which were positive for H. pylori and three of three cats at 2 weeks p.t. had dental plaque which was positive for H. pylori. At 6 weeks p.t., all six cats had H. pylori-negative cultures for samples from several gastric sites taken at necropsy, and only one cat had H. pylori cultured from gastric juice. PCR analysis revealed that five of six cats had H. pylori DNA amplification products from plaque, saliva, and/or gastric fluid samples. Negative bacterial cultures for cats for which there was demonstrable PCR amplification of H. pylori DNA may reflect the inability of in vitro culture techniques to isolate small numbers of H. pylori organisms, focal colonization at sites not cultured, or a failure of the antibiotics to successfully eradicate H. pylori from extragastric sites which allowed subsequent recolonization of the stomach after cessation of therapy. Alternatively, the treatment strategy may have induced in vivo viable but nonculturable coccoid forms of H. pylori. The H. pylori cat model should allow further studies to test these hypotheses as well as the efficacies of other combined therapeutic regimens. Also, because 100% of these cats were naturally infected with H.pylori, this model should prove useful in exploring mechanisms whereby human populations in underdeveloped countries, which have H. pylori infection rates approaching 100%, have a high rate of recurrence of H. pylori infection after use of prescribed antibiotic therapies that successfully eradicate H. pylori in individuals in developed countries.

Chronic proliferative hepatitis in A/JCr mice associated with persistent Helicobacter hepaticus infection: a model of helicobacter-induced carcinogenesis

Helicobacter hepaticus causes hepatitis in selected strains of mice and in A/JCr mice is linked to liver cancer. To analyze whether H. hepaticus persists in specified ecological niches, to determine whether biomarkers of infection exist, and to analyze the influence of H. hepaticus on hepatocyte proliferation, a longitudinal study of H. hepaticus-infected A/JCr mice was undertaken. A/JCr mice were serially euthanatized from 3 through 18 months and surveyed by enzyme-linked immunosorbent assay; bacterial culture of liver, colon, and cecum; histology; electron microscopy; hepatocyte proliferation indices determined by using 5-bromo-2'-deoxyuridine; and measurement of the liver enzyme alanine aminotransferase. In infected animals throughout the 18-month study, H. hepaticus was consistently isolated from the lower bowel but only sporadically from the liver. By electron microscopy, H. hepaticus was noted infrequently and only in bile canaliculi. Infected mice, particularly males, showed chronic inflammation; oval cell, Kupffer cell, and Ito cell hyperplasia; hepatocytomegaly; and bile duct proliferation. The inflammatory and necrotizing lesion was progressive and involved the hepatic parenchyma, portal triads, and intralobular venules. Hepatic adenomas were noted only in male mice, whereas 5-bromo-2'-deoxyuridine proliferation indices were markedly increased in both sexes, but especially in males, compared to control A/J mice. Infected mice also developed sustained anti-H. hepaticus serum immunoglobulin G antibody responses and elevated alanine aminotransferase levels. H. hepaticus, which persists in the lower bowels and livers of A/JCr mice, is associated with a chronic proliferative hepatitis, and hepatomas in selected male mice indicate that this novel bacterium may cause an increased risk of hepatic cancer induction in susceptible strains of mice. This murine model should prove useful in dissecting the molecular events operable in the development of neoplasms induced by bacteria belonging to this expanding genera of pathogenic Helicobacter species.

Natural and experimental Helicobacter mustelae reinfection following successful antimicrobial eradication in ferrets

BACKGROUND

Recrudescence or reinfection may occur after eradication of Helicobacter pylori in humans.

MATERIALS AND METHODS

We used the ferret Helicobacter mustelae model to investigate the effect of prior infection and eradication on reinfection by experimental and natural routes. Two groups of ferrets with naturally acquired H. mustelae infection were treated with an eradication protocol using amoxicillin, metronidazole, and bismuth subsalicylate. The ferrets were monitored for recrudescence by repeated cultures of endoscopic gastric mucosal biopsies. The ferrets were challenged at 17 months (group I) and 6 months (group II) after eradication with a strain of H. mustelae having a distinctive restriction endonuclease analysis pattern. The eradication protocol was repeated to eliminate the infection produced by experimental challenge. The ferrets were then cohoused intermittently with naturally infected ferrets.

RESULTS

The original H. mustelae infection was successfully eliminated by the eradication protocol. No recrudescence was observed in group I for 12 months nor for 3 months in group II after eradication. All ferrets became persistently reinfected with the challenge strain. The infection from the challenge strain was eradicated successfully. No ferrets in group I and all ferrets in group II became infected through cohousing.

CONCLUSIONS

These results suggest that though prior infection with H. mustelae may confer some protection against reinfection, such protection is not universal in all circumstances; that susceptibility to reinfection by contact with infected animals varies between individuals; and that age may be a factor in this individual variability. These results are applicable to studies of reinfection after eradication of H. pylori in humans.

Cystic urogenital anomalies in ferrets (Mustela putorius furo)

Single or multiple semispherical to bilobulated fluid-filled cystic structures of variable size were observed on the dorsal aspects of the urinary bladder of four male and two female ferrets (Mustela putorius furo). All ferrets had been neutered. On physical examination, the cysts were palpated as caudal abdominal masses. Three of the six ferrets presented with dysuria, and two ferrets had signs compatible with endocrine dysfunction. Adrenal cortical hyperplasia or neoplasia were observed in all of the five ferrets examined. Sex hormones assayed in one of the six ferrets revealed elevated levels of serum estrodiol. The posterior aspect of the cysts was located on and/or attached to the trigone or neck of the bladder, with variable intraluminal communication with the bladder and/or the urethra. The anterior aspect of the cysts projected dorsally or dorsocranially into the caudal abdomen. The cysts were thin walled and contained urinelike fluid (n = 5) or viscous yellow fluid (n = 1). Histologically, the cyst walls were composed of three layers, epithelium, muscle, and serosa, with fibrovascular stroma between layers. The epithelium consisted of simple to stratified transitional, columnar, or squamous epithelial cells. The muscular layer consisted of intermittent bundles and/or single to double layers of continuous to discontinuous smooth muscle. The serosal layer consisted of loose fibrous stroma covered by flattened mesothelial cells. The cystic anomalies in these ferrets were most likely derived from the urogenital glands/ducts or other remnants.

Eosinophil granulocytic sarcoma in a New Zealand white rabbit

An 18-month-old New Zealand White rabbit developed a rapidly growing firm perianal mass. Within 2 months, the mass increased in size from 4.0 x 2.0 cm to 7.5 x 7.0 x 3.5 cm. Cut surfaces of the mass were white to yellow with foci of hemorrhage. Histopathologic examination revealed neoplastic granulocytes that invaded the dermis of the overlying skin, subcutaneous tissue, and the regional skeletal muscle. The tumor was comprised of myeloid cells with large eosinophilic cytoplasmic granules that had the histochemical and ultrastructural features of eosinophils. This is the first report of an eosinophil granulocytic sarcoma in lagomorphs.

Inability of an isogenic urease-negative mutant stain of Helicobacter mustelae to colonize the ferret stomach

Eight ferrets specific-pathogen-free for Helicobacter mustelae were given, per dose, approximately 3.0 x 10(7) CFU of either the wild-type parent strain of H. mustelae (NCTC 12032) (two ferrets) the isogenic urease-negative mutant strain of H. mustelae (10::Tn3Km) (four ferrets), or sterile culture broth (two ferrets). Infection status was monitored by endoscopic gastric biopsy for urease activity, histopathology, and culture and by serology at 3, 6, 10, and 21 weeks. All ferrets were necropsied at 25 weeks. Both negative control ferrets remained uninfected, both ferrets receiving the H. mustelae wild-type parent strain became infected after two doses of the organism, and all four ferrets given two doses of the isogenic urease-negative mutant strain of H. mustelae remained uninfected throughout the 6-month study. Histopathology correlated with infection status. H. mustelae-infected ferrets exhibited diffuse mononuclear inflammation in the subglandular region and the lamina propria of the gastric mucosa, while uninfected ferrets showed no or minimal inflammation. These results suggest that urease activity is essential for colonization of the ferret stomach by H. mustelae.

Effect of Helicobacter mustelae infection on ferret gastric epithelial cell proliferation

The effect of Helicobacter mustelae infection on gastric epithelial proliferation was studied in ferrets colonized with H.mustelae and specific pathogen-free (SPF) ferrets not infected with H.mustelae. Thirteen H. mustelae-infected ferrets between the ages of 13 and 32 months and 16 SPF ferrets between 6 and 18 months were analyzed. Bacterial cultures, urease tests and Warthin-Starry stains were used to identify H.mustelae. Tissues obtained from the antrum and the body regions of the stomach were assayed by proliferating cell nuclear antigen (PCNA) immunohistochemistry and measured using a computerized color image analysis system. PCNA-expressing gastric epithelia in the antrum and the body regions were significantly increased in the H.mustelae-infected ferrets versus the SPF ferrets (P < 0.001). PCNA positivity in the antrum regions of both the H.mustelae-infected ferrets and SPF ferrets was significantly higher than that of the body regions (P < 0.001). Comparison of the histopathology of infected ferrets indicated that PCNA positivity correlated with the histological severity of gastritis. This study suggests that cell proliferation in ferret gastric mucosa increases with H.mustelae infection and provides evidence that PCNA is a useful biomarker for studying the changes in cell kinetics in the ferret stomach. The data also further support the use of the H.mustelae-infected ferret as an animal model for studying the pathogenesis of Helicobacter pylori-induced gastric diseases of humans.

Helicobacter pylori-induced gastritis in the domestic cat

Helicobacter pylori has been cultured from the inflamed gastric mucosae of naturally infected cats; the lesions in H. pylori-infected cat stomachs mimic many of the features seen in H. pylori-infected human stomachs. To determine whether H. pylori-negative specific-pathogen-free cats with normal gastric mucosae were susceptible to colonization by this bacterium and whether gastritis developed after infections, four H. pylori-negative cats treated with cimetidine were orally dosed three times with 3 ml (1.5 x 10(8) CFU/ml) of H. pylori every 4 days. All four cats became persistently colonized as determined by gastric cultures and PCRs from serial gastric biopsy samples and necropsy samples at 7 months postinfection. H. pylori was not isolated from the two control cats, nor were their gastric tissues positive by PCR; one of the two cats had a few focal lymphocytic aggregates in the body submucosa, whereas the second cat had a normal gastric mucosa. All four H. pylori-infected cats had multifocal gastritis consisting of lymphoid aggregates plus multiple large lymphoid nodules, which were most noticeable in the antral mucosa. In addition, one H. pylori-infected cat had a moderate diffuse infiltration of polymorphonuclear leukocytes in the subglandular region of the antrum. H. pylori-like organisms were focally distributed in glandular crypts of the antrum. Two of the H. pylori-infected cats had significant (eightfold) increases over baseline in levels of immunoglobulin G H. pylori serum antibody. The H. pylori isolates from the four experimentally infected cats had restriction fragment length polymorphism patterns specific for the flaA gene that were identical to those of the inoculating strain. H. pylori readily colonizes the cat stomach and produces persistent gastritis.

Helicobacter bilis sp. nov., a novel Helicobacter species isolated from bile, livers, and intestines of aged, inbred mice

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new helicobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bilis is responsible for causing chronic hepatitis and/or hepatocellular tumors in mice.

Effect of oral immunization with recombinant urease on murine Helicobacter felis gastritis

The ability of oral immunization to interfere with the establishment of infection with Helicobacter felis was examined. Groups of Swiss Webster mice were immunized orally with 250 micrograms of Helicobacter pylori recombinant urease (rUrease) and 10 micrograms of cholera toxin (CT) adjuvant, 1 mg of H. felis sonicate antigens and CT, or phosphate-buffered saline (PBS) and CT. Oral immunization with rUrease resulted in markedly elevated serum immunoglobulin G (IgG), serum IgA, and intestinal IgA antibody responses. Challenge with live H. felis further stimulated the urease-specific intestinal IgA and serum IgG and IgA antibody levels in mice previously immunized with rUrease but activated primarily the serum IgG compartment of PBS-treated and H. felis-immunized mice. Intestinal IgA and serum IgG and IgA anti-urease antibody responses were highest in rUrease-immunized mice at the termination of the experiment. Mice immunized with rUrease were significantly protected (P < or = 0.0476) against infection when challenged with H. felis 2 or 6 weeks post-oral immunization in comparison with PBS-treated mice. Whereas H. felis-infected mice displayed multifocal gastric mucosal lymphoid follicles consisting of CD45R+ B cells surrounded by clusters of Thy1.2+ T cells, gastric tissue from rUrease-immunized mice contained few CD45R+ B cells and infrequent mucosal follicles. These observations show that oral immunization with rUrease confers protection against H. felis infection and suggest that gastric tissue may function as an effector organ of the mucosal immune system which reflects the extent of local antigenic stimulation.

Helicobacter bilis sp. nov., a novel Helicobacter species isolated from bile, livers, and intestines of aged, inbred mice

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new helicobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bilis is responsible for causing chronic hepatitis and/or hepatocellular tumors in mice.

Total knee arthroplasty after patellectomy

We compared the outcome of total knee arthroplasty in 19 patients who had had previous patellectomy with the results in a matched series of arthroplasties performed on knees in which the patella was intact. The mean follow-up was 63 months (21 to 114). In the study group, the outcome was poor in five patients. There was instability in the coronal plane in three patients and persistent pain in four. Three supracondylar fractures occurred. The overall complication rate was 36%. In the control group, pain was relieved in every case and there were no complications. Total knee arthroplasty has a higher complication rate and inferior results if the knee has undergone prior patellectomy.

Total knee arthroplasty after patellectomy

We compared the outcome of total knee arthroplasty in 19 patients who had had previous patellectomy with the results in a matched series of arthroplasties performed on knees in which the patella was intact. The mean follow-up was 63 months (21 to 114). In the study group, the outcome was poor in five patients. There was instability in the coronal plane in three patients and persistent pain in four. Three supracondylar fractures occurred. The overall complication rate was 36%. In the control group, pain was relieved in every case and there were no complications. Total knee arthroplasty has a higher complication rate and inferior results if the knee has undergone prior patellectomy.

Evaluation of detomidine anesthetic combinations in the rabbit

Detomidine, a potent alpha 2-adrenergic receptor agonist, was chosen for study alone and in combination with ketamine with or without diazepam. Four regimens were evaluated: detomidine (150 micrograms/kg of body weight) alone (D); ketamine (35 mg/kg) and detomidine (150 micrograms/kg) (KD); ketamine (35 mg/kg) and high-dose detomidine (300 micrograms/kg) (KDh); and ketamine (35 mg/kg), diazepam (1 mg/kg), and detomidine (150 micrograms/kg) (KDD). The same six rabbits were anesthetized with each combination at weekly intervals. Atropine (0.04 mg/kg) was administered as a preanesthetic 5 min prior to test substance administration. All agents were administered IM, except for diazepam, which was administered IV. Heart and respiratory rates, mean arterial blood pressure, and arterial blood gas tensions were measured. Pedal, palpebral, and righting reflexes also were evaluated. Cardiopulmonary depression, as indicated by decrease in heart and respiratory rates, blood pH, PO2, and increase in PCO2, was observed in all groups. With the exception of heart rate, detomidine used alone caused the least depression of these parameters. Reflexes were consistently lost only after KDh and KDD administrations. The pedal reflex, used as an index of anesthetic depth, was lost in response to KDh and KDD for 56.7 +/- 11.6 and 43.8 +/- 7.4 min, respectively (mean +/- SEM). Three of the six rabbits were anorectic after KDh administration. Necropsy and histologic evaluation revealed myocardial necrosis and fibrosis in five animals. Due to the inconsistent reflex loss in response to KD and D and inappetance associated with KDh, these combinations were not considered safe or reliable.(ABSTRACT TRUNCATED AT 250 WORDS)

Megaesophagus in nine ferrets

Megaesophagus was diagnosed in 9 adult ferrets. Clinical history of the ferrets included regurgitation, difficulty in swallowing, partial anorexia, and lethargy. Cachexia, dehydration, weakness, and ptyalism were observed on physical examination. Radiography revealed the esophagus of each ferret to be dilated in the thoracic and cervical regions. Of 4 ferrets that had lymphocytopenia, 2 had concurrent leukopenia. Serum biochemical analysis revealed high activity of alanine transaminase (4 ferrets) and aspartate transaminase (3), and hypoglycemia (4). Treatment included administration of fluid, antibiotics, and agents directed against possible primary causes of megaesophagus. Treatments were ineffective, and all of the ferrets died or were euthanatized. All 6 ferrets that were submitted for necropsy had bronchopneumonia, hepatic lipidosis, mild esophagitis, and gastritis. The etiopathogenesis of megaesophagus in the ferrets was not determined.

Probable transmission of Chlamydia psittaci from a macaw to a cat

A 5-year-old Siamese cat developed unilateral mucopurulent ocular discharge and conjunctivitis 1 month after the introduction of a macaw into the household. Despite treatment with antimicrobial ophthalmic ointment, the conjunctivitis became bilateral and other systemic signs developed. Intracellular inclusions consistent with a Chlamydia psittaci infection were detected in conjunctival epithelial cells stained with a fluorescein-labeled monoclonal antibody. Chlamydia psittaci was isolated from samples obtained by conjunctival scraping. Subsequently, C psittaci was recovered in samples obtained from the feces of the bird. The cat and the bird were successfully treated with doxycycline. Historic and epidemiologic findings supported the theory of orthozoonotic transmission of C psittaci from the bird to the cat.