Efficacy of moxidectin, using various dose regimens, against JYD-34, a macrocyclic lactone resistant isolate of Dirofilaria immitis

BACKGROUND

Macrocyclic lactones (MLs) are the only class of drugs currently commercially available that are effective for preventing heartworm disease. The data presented in this article provide information on the efficacy of oral moxidectin against JYD-34, a known ML-resistant Dirofilaria immitis isolate, when dogs are treated under various dosing regimens.

METHODS

Fifty-two purpose-bred Beagle dogs were used in five laboratory studies. All dogs were inoculated with 50 D. immitis third-stage larvae (L3) (JYD-34 isolate) 30 days prior to the first treatment. Dogs were randomized to treatment (four to five animals in each group) with one, three, or five monthly doses of oral moxidectin ranging from 6 to 100 µg/kg body weight. In each study, control dogs were not treated. Five to 6 months after L3 inoculation, dogs were euthanized, and adult worms were counted to evaluate efficacy of the dosing regimens.

RESULTS

Adult heartworms were recovered from all control dogs, with an overall geometric mean of 29.7 worms (range 15.2 to 38.0, individual counts ranged from 8 to 51). Five monthly doses of 6 µg/kg provided 83.3% and 90.2%, efficacy, and the same number of monthly doses of 9 µg/kg demonstrated 98.8% and 94.1% efficacy. Three monthly doses of 30 and 50 µg/kg demonstrated 97.9% and 99.0% efficacy, respectively, while a single dose of 100 µg/kg demonstrated 91.1% efficacy.

CONCLUSIONS

Five monthly doses of 9 µg/kg provided similar or only marginally lower efficacy against JYD-34, a known ML-resistant isolate, compared to substantially higher doses administered for 3 months. This underscores the importance of duration of exposure to moxidectin when facing ML-resistant isolates. Repeated administration of lower doses of moxidectin are an alternative to higher doses in the prevention of heartworm disease associated with less susceptible or resistant isolates.

Effects of doxycycline dose rate and pre-adulticide wait period on heartworm-associated pathology and adult worm mass

BACKGROUND

The American Heartworm Society canine guidelines recommend treatment with doxycycline prior to adulticide administration to reduce levels of Wolbachia and its associated metabolites, which are known to be a leading cause of pulmonary pathology. Studies have determined that doxycycline administered at 10 mg/kg BID for 28 days is an effective dose for eliminating Wolbachia, but what has not been determined is the clinical relevance of this elimination. The current guidelines also recommend a 30-day wait period following administration of doxycycline to allow for clearance of metabolites, such as Wolbachia surface protein, and for further reduction in heartworm biomass before administration of adulticide. Reducing the doxycycline dose and eliminating the wait period may carry practical benefits for the animal, client, and practitioner.

METHODS

To investigate these treatment practices, Dirofilaria immitis adults were surgically transplanted into each of 45 dogs, which were divided into nine study groups of five dogs each. Seventy-five days after transplantation, two groups each were administered 5, 7.5, or 10 mg/kg BID doxycycline orally for 28 days and 6 µg/kg ivermectin monthly, with three untreated groups serving as controls. Study animals were necropsied and examined prior to treatment as well as 30 and 60 days post-treatment.

RESULTS

Mean worm weight was unaffected by dosage but exhibited a significant increase at 30 days and significant decrease at 60 days post-treatment, including in control groups. Histopathology lesion scores did not significantly differ among groups, with the exception of the lung composite score for one untreated group. Liver enzymes, the levels of which are a concern in doxycycline treatment, were also examined, with no abnormalities in alanine aminotransferase or alkaline phosphatase observed.

CONCLUSIONS

No consistent worsening of tissue lesions was observed with or without the AHS-recommended 30-day wait period, nor did reduced dosages of doxycycline lead to worsening of pathology or any change in efficacy in depleting worm weight. Mean worm weight did significantly increase prior to, and decrease following, the wait period. Future work that also includes adulticide treatment (i.e. melarsomine) will study treatment recommendations that may improve both animal health and owner compliance.

Dirofilariasis mouse models for heartworm preclinical research

Introduction

Dirofilariasis, including heartworm disease, is a major emergent veterinary parasitic infection and a human zoonosis. Currently, experimental infections of cats and dogs are used in veterinary heartworm preclinical drug research.

Methods

As a refined alternative in vivo heartworm preventative drug screen, we assessed lymphopenic mouse strains with ablation of the interleukin-2/7 common gamma chain (γc) as susceptible to the larval development phase of Dirofilaria immitis.

Results

Non-obese diabetic (NOD) severe combined immunodeficiency (SCID)γc^-/- (NSG and NXG) and recombination-activating gene (RAG)2^-/-γc^-/- mouse strains yielded viable D. immitis larvae at 2-4 weeks post-infection, including the use of different batches of D. immitis infectious larvae, different D. immitis isolates, and at different laboratories. Mice did not display any clinical signs associated with infection for up to 4 weeks. Developing larvae were found in subcutaneous and muscle fascia tissues, which is the natural site of this stage of heartworm in dogs. Compared with in vitro-propagated larvae at day 14, in vivo-derived larvae had completed the L4 molt, were significantly larger, and contained expanded Wolbachia endobacteria titres. We established an ex vivo L4 paralytic screening system whereby assays with moxidectin or levamisole highlighted discrepancies in relative drug sensitivities in comparison with in vitro-reared L4 D. immitis. We demonstrated effective depletion of Wolbachia by 70%-90% in D. immitis L4 following 2- to 7-day oral in vivo exposures of NSG- or NXG-infected mice with doxycycline or the rapid-acting investigational drug, AWZ1066S. We validated NSG and NXG D. immitis mouse models as a filaricide screen by in vivo treatments with single injections of moxidectin, which mediated a 60%-88% reduction in L4 larvae at 14-28 days.

Discussion

Future adoption of these mouse models will benefit end-user laboratories conducting research and development of novel heartworm preventatives via increased access, rapid turnaround, and reduced costs and may simultaneously decrease the need for experimental cat or dog use.

Inability of Dirofilaria immitis infective larvae from mosquitoes fed on blood from microfilaremic dogs during low-dose and short-treatment regimens of doxycycline and ivermectin to complete normal development in heartworm naïve dogs

BACKGROUND

This study was conducted to determine whether heartworm infective larvae (L₃) collected from mosquitoes fed on dogs during low-dose, short-treatment-regimen doxycycline and ivermectin could develop normally in dogs.

METHODS

Twelve Beagles in a separate study were infected with 10 pairs of adult male and female Dirofilaria immitis by IV transplantation and randomly allocated to three groups of four dogs. Starting on Day 0, Group 1 received doxycycline orally at 10 mg/kg sid for 30 days plus ivermectin (min., 6 mcg/kg) on Days 0 and 30; Group 2 received doxycycline orally at 10 mg/kg sid until individual dogs became microfilaria negative (72-98 doses) and ivermectin every other week for six to seven doses. These dogs served as microfilaremic blood donors for the current mosquito studies. Aedes aegypti were allowed to feed on group-pooled blood samples from treated Groups 1-M and 2-M and untreated control Group 3-M on Days 22 (Study M-A) and 42 (Study M-C) and from Groups 1-M and 2-M on Day 29 (Study M-B) after treatment was started. From the Day 22 mosquito feeding, two dogs in Groups 1-M and 2-M and one dog in Group 3-M were given 50 L₃ by SC inoculation. From the Day 29 feeding, two dogs in Groups 1-M and 2-M were given 50 L₃. From the Day 42 feeding, two dogs in Group 1-M received 30 L₃, while two dogs in Group 2-M and one dog in Group 3-M received 40 L₃. All 14 dogs were necropsied for recovery and enumeration of adult heartworms 163-183 days PI.

RESULTS

None of the 12 dogs that received L₃ from mosquitoes fed on blood from treated dogs 22, 29 or 42 days after treatment started had any adult heartworms at necropsy, while the two control dogs had a total of 26 and 43 heartworms, respectively.

CONCLUSIONS

Treatment of microfilaremic dogs with doxycycline plus an ML, which later renders the L₃ incapable of normal development in the animal host, widens the scope of the multimodal approach to heartworm prevention in reducing the spread of heartworm disease.

Long-term evaluation of viability of microfilariae and intravenously transplanted adult Dirofilaria immitis in microfilaremic dogs treated with low-dose, short- and long-treatment regimens of doxycycline and ivermectin

BACKGROUND

Microfilarial (mf) counts were monitored over 21.3 months for any rebound that might occur in counts, and adulticidal efficacy was assessed following administration of low dosage with short- and long-treatment regimens of doxycycline and ivermectin to heartworm-microfilaremic dogs.

METHODS

Twelve heartworm-naïve beagles infected with 10 pairs of adult Dirofilaria immitis by intravenous transplantation were randomly allocated to three groups of four dogs. All treatments started on day 0. On day 0, Group 1 (short-treatment regimen) received doxycycline orally at 10 mg/kg once daily for 30 days plus ivermectin orally (minimum, 6 mcg/kg) on days 0 and 30. Group 2 (long-treatment regimen) received doxycycline orally at 10 mg/kg once daily until individual dogs became mf-negative (72-98 days) and ivermectin every other week until individual dogs became mf-negative (6-7 doses). Group 3 was the untreated control. Mf counts and antigen (Ag) tests were conducted. Dogs were necropsied for recovery and enumeration of heartworms on day 647.

RESULTS

Day -1 mean mf counts were 15,613, 23,950, and 15,513 mf/ml for groups 1, 2, and 3, respectively. Mean counts for Groups 1 and 2 declined until days 239 and 97, respectively, when all were negative. Group 3 had high mf counts throughout the study. There was not a rebound in mf counts in any of the treated dogs after they became amicrofilaremic. All dogs in group 1 and group 3 were Ag-positive throughout the study and had at least one live female worm at necropsy. All dogs in treated Group 2 were positive for Ag through day 154, but were antigen-negative on days 644 and 647, as all had only male worms. Mean live adult worm recoveries for Groups 1, 2, and 3 were 6.8 (range, 5-8), 3.3 (range, 1-6), and 16.0 (range, 14-17), respectively, with a percent reduction in adult worm counts of 57.5% for Group 1 and 79.3% for Group 2.

CONCLUSIONS

These data lend support to the use of the American Heartworm Society Canine Guidelines for adulticide therapy recommending the initiation of doxycycline plus a macrocyclic lactone (ML) at the time of the heartworm-positive diagnosis.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against Amblyomma americanum in cats

Esafoxolaner, a purified enantiomer of afoxolaner with insecticidal and acaricidal properties, is combined with eprinomectin and praziquantel in NexGard® Combo, a novel topical endectoparasiticide product for cats. The efficacy of this novel formulation was assessed in two experimental studies against induced infestations with Amblyomma americanum, a tick species of major importance, highly prevalent in a large southeastern quarter of the United States. In each study, 10 cats were randomly allocated to a placebo control group and 10 cats to a novel formulation treated group. Infested cats were treated topically once at the minimum recommended dose. Both studies were designed to test curative efficacy on existing infestation, 72 h after treatment, and to test preventive efficacy, 72 h after subsequent weekly (Study #1) or fortnightly (Study #2) infestations for one month. For each infestation, all cats were infested with 50 unfed adult A. americanum. At each tick count, in both studies, at least 8 in 10 placebo control cats were infested with 13 (26%) or more live ticks, demonstrating adequate infestation throughout the studies. Curative efficacy of the novel formulation was 99% in both studies; preventive efficacy was 92% and 100% for at least one month.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel for the prevention of heartworm disease in cats

NexGard® Combo is a novel topical endectoparasiticide formulation for cats combining the insecticide/acaricide esafoxolaner, the nematodicide eprinomectin and the cestodicide praziquantel. The efficacy of this novel formulation for the prevention of heartworm disease in cats was tested in two experimental studies using an induced infection model and a randomized, blinded, placebo-controlled study design, and two USA isolates of Dirofilaria immitis. In each study, 20 naïve cats were each inoculated sub-cutaneously with 100 third-stage larvae of D. immitis 30 days before treatment. Following randomization to two treatment groups of ten cats, each cat was treated topically once, either with the minimum recommended dose of the novel formulation, or with an identical volume of placebo. Five months after treatment (6 months after infections), the cats were humanely euthanized for parasite recovery and count. Efficacy was calculated by comparison of the numbers of adult D. immitis recovered in the control and in the novel formulation groups. In the control groups of each study, D. immitis were recovered in seven and nine cats (respective worm counts ranges 1-7 and 1-16, respective geometric means 1.6 and 5.1). In both studies, none of the treated cats harbored any D. immitis at necropsy and the calculated efficacy of the novel formulation was 100%. There were no adverse reactions related to treatment with the novel formulation. The results of these two studies demonstrate that a topical NexGard® Combo application at the minimum label dose is well-tolerated and efficacious in preventing heartworm disease in cats.

Macrofilaricidal Benzimidazole-Benzoxaborole Hybrids as an Approach to the Treatment of River Blindness: Part 1. Amide Linked Analogs

A series of benzimidazole–benzoxaborole hybrid molecules linked via an amide linker are described that exhibit good in vitro activity against Onchocerca volvulus, a filarial nematode responsible for the disease onchocerciasis, also known as river blindness. The lead identified in this series, 8a (AN8799), was found to have acceptable pharmacokinetic properties to enable evaluation in animal models of human filariasis. Compound 8a was effective in killing Brugia malayi, B. pahangi, and Litomosoides sigmodontis worms present in Mongolian gerbils when dosed subcutaneously as a suspension at 100 mg/kg/day for 14 days but not when dosed orally at 100 mg/kg/day for 28 days. The measurement of plasma levels of 8a at the end of the dosing period and at the time of sacrifice revealed an interesting dependence of activity on the extended exposure for both 8a and the positive control, flubendazole.

Evaluation of Dirofilaria immitis antigen detection comparing heated and unheated serum in dogs with experimental heartworm infections

Background

To evaluate whether heated serum allows for earlier detection of Dirofilaria immitis antigen, dogs with experimental D. immitis infections underwent weekly blood sampling to compare antigen results using both heated and unheated serum.

Methods

One of two isolates (JYD-34 or Big Head™) were used to infect naïve laboratory beagle dogs. Serum was collected from dogs weekly and divided into two aliquots, heated and unheated. The samples designated as heated were placed in a heat block at 104 °C for 10 min then centrifuged with collection of the resulting supernatant. Two commercial ELISAs, DiroCHEK® (Synbiotics Corporation, Zoetis) and PetChek® (IDEXX Laboratories, Inc.), were used to conduct D. immitis antigen testing on all serum samples.

Results

There was no statistical difference in the mean number of days from infection to positive D. immitis antigen status between the two commercial testing kits (DiroCHEK® versus PetChek®) with either heated or unheated serum. When unheated serum was utilized, very strong agreement between the two assays was demonstrated using Lin’s concordance correlation coefficient (R_c = 0.98). However, when heated serum was compared, Lin’s concordance correlation coefficient was only R_c = 0.64, showing a lesser agreement. There was a statistical difference in the mean number of days from infection to a positive test result for unheated serum when compared to mean days to positive status with heated serum. For DiroCHEK® the heated serum yielded a positive result 126.9 ± 18.9 days postinfection while the unheated serum yielded a positive result 162.6 ± 23.0 days postinfection; this was a significant 35.7 ± 32.2 days longer, on average, compared with heated serum. With PetChek® the heated serum yielded a positive result 131.5 ± 11.7 days postinfection while the unheated serum yielded a positive result 162.8 ± 23.8 days postinfection; this was a significant 31.3 ± 25.5 days longer, on average, compared with heated serum. The detection of D. immitis antigen earlier using heated serum was consistent for both heartworm isolates.

Conclusion

Our results suggest heat treatment of serum may allow earlier detection of D. immitis antigen but with less consistency demonstrated across two testing platforms as compared with antigen detection using unheated serum.

Shifting the paradigm in Dirofilaria immitis prevention: blocking transmission from mosquitoes to dogs using repellents/insecticides and macrocyclic lactone prevention as part of a multimodal approach

BACKGROUND

This study assessed the influence of a topical ectoparasiticide (dinotefuran-permethrin-pyriproxyfen, DPP, Vectra® 3D, Ceva Animal Health) combined with a macrocyclic lactone (milbemycin oxime, MBO, Interceptor®, Virbac) on transmission of heartworm L3 from mosquitoes to dogs and subsequent development of worms in treated dogs exposed to infected mosquitoes.

METHODS

Thirty-two beagle dogs were allocated to four groups of eight: Group 1, untreated controls; Group 2, treated topically with DPP on Day 0; Group 3, treated orally with MBO on Day 51; and Group 4, treated with DPP on Day 0 and MBO on Day 51. Dogs were exposed under sedation for 1 h to Dirofilaria immitis (JYD-34)-infected Aedes aegypti on Days 21 and 28. At the end of each exposure, mosquitoes were classified as live, moribund, or dead and engorged or non-engorged. Live or moribund mosquitoes were incubated for daily survival assessment for 3 days. Mosquitoes were dissected before and after exposure to estimate the number of L3 transmitted to each dog. Dogs were necropsied 148 to 149 days postinfection.

RESULTS

A total of 418 mosquitoes fed on the 16 dogs in Groups 1 and 3, while only 6 fed on the 16 DPP-treated dogs in Groups 2 and 4. Mosquito anti-feeding (repellency) effect in Groups 2 and 4 was 98.1 and 99.1%, respectively. The estimated numbers of L3 transmitted to controls, DPP-treated, MBO-treated and DPP + MBO-treated dogs were 76, 2, 78, and 1, respectively. No heartworms were detected in any of the DPP + MBO-treated dogs (100% efficacy), while 8 out of 8 were infected in the control group (range, 21-66 worms per dog), 8 out of 8 were infected in the MBO-treated group (58% efficacy), and 3 out of 8 were infected in the DPP-treated group (96% efficacy).

CONCLUSIONS

DPP repelled and killed most mosquitoes that were capable of transmitting heartworm L3 to dogs. The "Double Defense" protocol of DPP + MBO had better efficacy for protecting dogs against heartworm transmission and infection than MBO alone. This added DPP benefit is more pronounced when macrocyclic lactone-resistant strains of heartworms are involved or lack of compliance in macrocyclic lactone administration is known or suspected.

The development of a new test of children's braille-reading ability

This article outlines a project (School of Education, University of Birmingham) which aims to develop a new comprehensive test of children's braille-reading skills. The Project Management Group has decided to adapt the new print Neale Analysis of Reading Ability (1989) for braille users. This diagnostic test of prose-reading ability yields measures of reading speed, accuracy and comprehension. When adapting narratives for use by braillists, several key areas require careful consideration including assessing comparative difficulties, capitalization and the replacement of pictures. These areas are addressed, as well as other matters concerned with the standardization sample and the rationale behind the decision to opt for the Neale test.

Network 1000: the changing needs and circumstances of visually-impaired people: project overview

This article outlines the progress of a newly-commissioned three year study known as Network 1000. It is a three-year project funded through the Community Fund and is being carried out by the University of Birmingham on behalf of Vision 2020. The project’s aim is to create a panel survey of 1000 visually-impaired people to be interviewed regularly over the three-year period, and hopefully beyond, enabling their changing needs and circumstances to be monitored over time. The findings will be used to influence policy-makers and service-providers, and will also be disseminated to a wider audience of people with an interest in visual impairment. Building on the longitudinal nature of the project enables the project team to develop a methodology that is both democratic and inclusive. The underlying research philosophy is one of inclusion and participation and in this respect the people this research affects the most - those who are visually impaired - are involved in all stages of the research process. People with a visual impairment have played a key role in generating the data and the themes that will drive the construction of the main survey instrument. The article is divided into five sections that describe the progress of the project to date: first, it briefly outlines the background to the project; second, it describes the underlying philosophy behind the democratic approach to inclusion and participant involvement; third, it presents preliminary results from generative interviews; fourth, it discusses how the team will recruit participants to the project with particular reference to the two-stage sample design that has been adopted; and finally, it describes how this two-stage approach will be operationalized. The article concludes by outlining the next phase of the project and with a short reflection on the research process to date.

PO-42 - A novel approach to a common problem: after-hours care of cancer patients diagnosed with VTE

INTRODUCTION

Oncologists often receive phone calls from radiologists after regular working hours or while on call, informing them that a cancer patient has been diagnosed with a blood clot. In these situations, there may not be nursing staff available to contact the patient and provide teaching for Low Molecular Weight Heparin (LMWH) injections. As a result, patients are often sent to the emergency for injection and teaching, taxing an already overburdened emergency department. This problem constitutes an important care gap.

AIM

In Alberta, Canada, pharmacists are able to prescribe medications including LMWH. We designed an after-hours program to provide care for cancer patients diagnosed with VTE.

MATERIALS AND METHODS

Once the oncologist is made aware of the patient with a clot, a simple one page document is filled out and faxed to a 24-hour outpatient pharmacy outlining the following: patient demographics, clot location, systemic therapy, current anticoagulant and anti-platelet agents. The oncologist has the option to specify desired LMWH. The patient goes to the pharmacy where the pharmacist weighs the patient, reviews blood work electronically and prescribes the LMWH. Also provided are injection teaching and telephone follow-up. A specific algorithm is followed with the pharmacist able to contact the on call oncologist in specific situations where the patient's condition falls outside of the algorithm guideline. The pharmacist is able to order blood work, particularly to evaluate for Heparin Induced Thrombocytopenia. Patients must follow up with their oncologist within 7 days of diagnosis.

RESULTS

This program has been run as a pilot and preliminary data will be presented at the ICTHIC meeting. Specifically, we will assess usage of the program, appropriateness of therapy chosen according to Canadian practice guidelines, as well as patient, pharmacist and physician satisfaction with the program.

CONCLUSIONS

We believe that this outpatient pharmacy program is innovative, will decrease burden on emergency departments, and takes advantage of our pharmacists' ability to independently assess patients and write prescriptions. This program may serve as a model for other cancer centers looking for a novel way to provide after-hours care of patients diagnosed with VTE.

Repellent and insecticidal efficacy of a new combination of fipronil and permethrin against three mosquito species (Aedes albopictus, Aedes aegypti and Culex pipiens) on dogs

Background

Three laboratory studies were conducted to assess the repellent and insecticidal efficacy of a combination of fipronil and permethrin (Frontline Tri- Act®/Frontect®) against three mosquito species (Aedes albopictus, Aedes aegypti and Culex pipiens) on dogs.

Methods

In each study, 16 healthy adult dogs were allocated to two groups. Eight dogs were treated with the new topical spot-on combination of fipronil and permethrin on Day 0 and the other eight dogs served as untreated controls. Each dog was exposed to mosquitoes on Days 1, 7, 14, 21 and 28 (and also on Day 35 in the A. aegypti study). After a 1-h exposure period, all mosquitoes were counted and categorized as live or dead and fed or non-fed. Live mosquitoes were kept in an insectary and observed for mortality counts 4, 24 and 48 h post-exposure (PE) for Aedes spp. and 24 and 48 h PE for C. pipiens. Repellency and insecticidal efficacies were defined as the percent reduction in the number of fed and live mosquitoes, respectively, in the treated group as compared to the untreated control group.

Results

Repellency against A. albopictus was ≥93.4% through Day 21 and 86.9% on Day 28. It was ≥91.0% through Day 35 against A. aegypti and ≥90.4% through Day 28 against C. pipiens. Insecticidal efficacy against A. albopictus was ≥97.1% at 24 h PE from Day 7 to Day 28. It was ≥98.0% for the first 3 weeks and still 75.7% on Day 35 against A. aegypti at 24 h PE. For C. pipiens, insecticidal efficacy ranged from 93.8% (Day 7) to 30.9% (Day 28) at 48 h PE.

Conclusions

A single topical administration of the combination of fipronil and permethrin provides repellency against mosquitoes on dogs for at least 4 weeks. The product may therefore significantly reduce the potential for the transmission of vector-borne pathogens through the inhibition of mosquito feeding, as well as the discomfort associated with mosquito bites. Moreover, mosquito mortality was induced by contact with the treated dogs, which could aid in the control of mosquitoes, and hence the control of mosquito-borne diseases, in the local vicinity of treated dogs.

The role of nonenzymatic glycation and carbonyls in collagen cross-linking for the treatment of keratoconus

PURPOSE

Corneal cross-linking (CXL) is a treatment for keratoconus that eliminates the need for keratoplasty in most patients. However, its molecular mechanisms remain under study. Advanced glycation end products (AGEs) have been suggested by many studies as the causative strengthening agent during CXL, though no studies to date have directly tested this hypothesis.

METHODS

Corneas of young rabbits and sharks were pretreated with pyridoxal hydrochloride and copper ions before CXL. Two known inhibitors of AGE formation, aminoguanidine and rifampicin, were applied during CXL in the treatment solution. Tensile strength tests were conducted after these experiments to detect diminished or accentuated corneal stiffening after CXL. SDS-PAGE was performed on type I collagen cross-linked in the absence and presence of AGE inhibitors.

RESULTS

Pretreatment with pyridoxal hydrochloride resulted in significantly higher corneal stiffening after CXL. AGE inhibitors significantly diminished cross-linking as detected by both tensile strength measurements using whole corneas and gel electrophoresis of in vitro cross-linking of type I collagen in solution, in the presence and absence of the inhibitors. Rifampicin inhibited CXL more significantly than aminoguanidine in gel electrophoresis and tensile strength tests, confirming recent findings on its efficacy as an AGE inhibitor.

CONCLUSIONS

Data presented here suggest that CXL is carbonyl dependent and involves the formation of AGE cross-links. Six possible cross-linking mechanisms are discussed.

Monitoring circulating tumor cells in cancer vaccine trials

The presence of circulating tumor cells (CTC) from various cancers has provided a wealth of information and possibilities. As the role of CTC detection in the treatment assessment of metastatic breast cancer becomes standard, there is interest in applying this tool in cancer vaccine development and clinical trial monitoring. Since we lack a proven immunologic assay that correlates with clinical response, CTC detection, quantification and phenotypic characterization may be a useful surrogate for clinical outcome. The Cancer Vaccine Development Program is involved in the development of HER2/neu peptide based vaccine development for the prevention of recurrence in HER2/neu expressing cancers like breast cancer. The CellSearch System (Veridex, LLC Warren, NJ) has been used by our lab in conjunction with in vivo and/or in vitro immunologic measurements to define a monitoring tool that could predict clinical response. Once validated, this assay could significantly shorten clinical trials and lead to more efficient assessment of potentially promising cancer vaccines.

Loss of heterozygosity of M6P/IGF2R gene is an early event in the development of prostate cancer

BACKGROUND

The genetic events leading to initiation and/or progression of prostate cancer are not well characterized. The gene coding for the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) has recently been identified as a tumor suppressor in several types of cancer. The purpose of the present study is to determine whether the M6P/IGF2R gene is inactivated in human prostate cancer, and if so, whether this is an early or late transformational event.

METHODS

In total, 43 patients with prostate cancer treated by radical prostatectomy, with archival material available for analysis, were assessed for loss of heterozygosity (LOH) in the M6P/IGF2R gene using six different gene-specific nucleotide polymorphisms. Regions of tumor, normal prostate and premalignant high-grade prostate intraepithelial neoplasia (PIN) were identified and cells were excised by laser capture microdissection (LCM). DNA segments were amplified using polymerase chain reaction (PCR).

RESULTS

The M6P/IGF2R gene was polymorphic in 83.7% (36/43) of patients, and 41.7% (15/36) of these informative patients had LOH in the tumor tissue. In 11/15 patients with LOH in malignant tissue, high-grade PIN could be identified, and 63.6% (7/11) also had LOH in this premalignant tissue.

CONCLUSIONS

This study is the first to find that the M6P/IGF2R gene is inactivated in prostate cancer. LOH in premalignant tissue as well suggests that mutation in the M6P/IGF2R gene is an early event in the development of prostate cancer, supporting the conclusion that it functions as a tumor suppressor gene in this disease.

Evaluation of PCR testing of ethanol-fixed nasal swab specimens as an augmented surveillance strategy for influenza virus and adenovirus identification

Viral culture isolation has been widely accepted as the "gold standard" for laboratory confirmation of viral infection; however, it requires ultralow temperature specimen storage. Storage of specimens in ethanol at room temperature could expand our ability to conduct active surveillance and retrospective screenings of viruses with rapid and inexpensive real-time PCR tests, including isolates from remote regions where freezing specimens for culture is not feasible. Molecular methods allow for rapid identification of viral pathogens without the need to maintain viability. We hypothesized that ethanol, while inactivating viruses, can preserve DNA and RNA for PCR-based methods. To evaluate the use of ethanol-stored specimens for augmenting surveillance for detection of influenza viruses A and B and adenoviruses (AdV), paired nasal swab specimens were collected from 384 recruits with febrile respiratory illness at Fort Jackson, S.C., in a 2-year study. One swab was stored at ambient temperature in 100% ethanol for up to 6 months, and the other swab was stored at -70 degrees C in viral medium. For viral detection, frozen specimens were cultured for a variety of respiratory viruses, and ethanol-fixed specimens were tested with TaqMan (TM) probe and LightCycler SYBR green (SG) melting curve assays with at least two different PCR targets for each virus. The sensitivities of the TM and SG assays on specimens stored in ethanol for 1 month were 75% and 58% for influenza A, 89% and 67% for influenza B, and 93 to 98% and 57% for AdV, respectively. Lower specificities of the real-time assays corresponded to the increased detection of PCR-positive but culture-negative specimens. Influenza virus RNA was detected as well or better after 6 months of storage in ethanol.

High magnetic field studies of the hidden order transition in URu2Si2

We studied in detail the low temperature/high magnetic field phases of URu2Si2 single crystals with specific heat, magnetocaloric effect, and magnetoresistance in magnetic fields up to 45 T. Data obtained down to 0.5 K, and extrapolated to T=0, show a suppression of the hidden-order phase at H0(0)=35.9+/-0.35 T and the appearance of a new phase for magnetic fields in excess of H1(0)=36.1+/-0.35 T observed only at temperatures lower than 6 K. In turn, complete suppression of this high field state is attained at a critical magnetic field H2(0)=39.7+/-0.35 T. No phase transitions are observed above 40 T. We discuss our results in the context of itinerant versus localized f electrons.

Experimenting on the past: the enigma of von Economo's encephalitis lethargica

Encephalitis lethargica (EL) was a complex and mysterious disease that appeared around the same time as the great influenza pandemic of 1918. The contemporaneous relationship of the 2 diseases led to speculation that they were causally related. Contemporary and subsequent observers conjectured that the influenza virus, directly responsible for the deaths of more than 20 million people, might also have been the cause of EL. A review of the extensive literature by observers of the EL epidemic suggests that most contemporary clinicians, epidemiologists, and pathologists rejected the theory that the 1918 influenza virus was directly responsible for EL. Disappearance of the acute form of EL during the 1920s has precluded direct study of this entity. However, modern molecular biology techniques have made it possible to examine archival tissue samples from victims of the 1918 pandemic in order to detect and study the genetic structure of the killer virus. Similarly, tissue samples from EL victims can now be examined for evidence of infection by the 1918 influenza virus.

Influenza RNA not detected in archival brain tissues from acute encephalitis lethargica cases or in postencephalitic Parkinson cases

Encephalitis lethargica (EL) was a mysterious epidemic. temporally associated with the 1918 Spanish influenza pandemic. Numerous symptoms characterized this disease, including headache, diplopia, fever, fatal coma, delirium, oculogyric crisis, lethargy, catatonia, and psychiatric symptoms. Many patients who initially recovered subsequently developed profound, chronic parkinsonism. The etiologic association of influenza with EL is controversial. Five acute EL autopsies and more than 70 postencephalitic parkinsonian autopsies were available in the Armed Forces Institute of Pathology (AFIP) tissue repository. Two of these 5 acute EL cases had histopathologic changes consistent with that diagnosis. The remaining 3 cases were classified as possible acute EL cases as the autopsy material was insufficient for detailed histopathologic examination. RNA lysates were prepared from 29 CNS autopsy tissue blocks from the 5 acute cases and 9 lysates from blocks containing substantia nigra from 2 postencephalitic cases. RNA recovery was assessed by amplification of beta-2-microglobulin mRNA and 65% of the tissue blocks contained amplifiable RNA. Reverse transcription-polymerase chain reaction (RT-PCR) for influenza matrix and nucleoprotein genes was negative in all cases. Thus, it is unlikely that the 1918 influenza virus was neurotropic and directly responsible for the outbreak of EL.

Object recognition may distort size perception

Size estimation may be influenced by characteristics recalled about the object viewed. This study evaluated the influence of object familiarity on estimation of size. We compared size estimates of several familiar objects with size estimates of undefined objects matched for dimensions of pattern and color. Those estimating the size of the familiar objects made significantly larger errors than those estimating the size of the undefined objects. In a second study size estimation errors from memory were larger than when objects were directly viewed. Experience with the objects appears to decrease accuracy of estimates of size but errors may be reduced by directly observing the object.

Effects of in-situ calibration of click stimuli on the auditory brainstem response

We studied the effects on the auditory brainstem response (ABR) of applying a computerized calibration procedure for click stimuli that corrects for individual transducer characteristics and ear canal acoustics. The "calibrated" signal at the eardrum possesses a nearly flat spectrum from 500 to 10,000 Hz. ABRs were recorded from normal-hearing subjects using both calibrated and uncalibrated clicks. The preponderance of energy for the latter stimulus was between 1000 and 4000 Hz. When compared to the responses evoked by the uncalibrated signal, ABRs to calibrated clicks displayed shorter component latencies, increased component amplitudes, and a more sensitive wave V relative to behavioral threshold.

Painful ophthalmoplegia caused by hemangiopericytoma of the cavernous sinus

Progressive, painful ophthalmoplegia developed in a 34-year-old man. MRI scan revealed an enhancing mass in the left cavernous sinus. Histologic examination of resected tumor revealed reticulin staining and cytologic features of hemangiopericytoma. Characteristics of intracranial hemangiopericytoma are reviewed.

Immunologic assessment during treatment of rheumatoid arthritis with anti-CD5 immunoconjugate

OBJECTIVE

To determine if sustained immunologic effects occurred after treatment of patients with rheumatoid arthritis (RA) with an immunoconjugate of murine anti-CD5 monoclonal antibody with ricin A chain (anti-CD5).

METHODS

We measured lymphocyte populations, mitogen induced peripheral blood mononuclear cell (PBMC) stimulation, cytokine levels, immunoglobulin levels, in vivo immune function, and clinical outcomes in 9 patients with RA treated with anti-CD5.

RESULTS

The treatment of patients with RA with anti-CD5 was associated with marked acute depletion of peripheral blood lymphocytes (p < 0.01) during and immediately after treatment. A sustained decrease in the number of CD3, CD4, CD5, and CD8 bearing lymphocytes persisted for 2 months after treatment (p < 0.05). After 3 months a mild decrease in the number of these lymphocyte populations persisted, but when compared to baseline values, the differences were not found to be statistically significant. Phytohemagglutinin induced PBMC proliferation was decreased at the 3-month followup (p < 0.05). Evaluations of mitogen induced cytokine and immunoglobulin production, immunoglobulin level, autoantibody, and in vivo antibody response to tetanus toxoid did not show any consistent change from baseline.

CONCLUSION

Anti-CD5 treatment of RA appears to be associated with a decrease in the population of cells bearing CD5, but does not appear to induce any persistent immunologic abnormalities.

Collagen-induced arthritis and TCRs in SWR and B10.Q mice expressing an Ek alpha transgene

B10.Ek alpha transgenic mice were mated with H2-E B10.Q and SWR mice. F1 and F1 x parental strain backcross progeny were tested for arthritis and autoimmune reactivity to mouse type II collagen (MII) after immunization with bovine, chick, deer, or human type II collagen. The results were correlated with the H-2 haplotype (b/q vs q/q) and the TCR V beta profile of peripheral blood T cells in each mouse. Hybrid progeny expressed TCR profiles different from either parent because of the TCR V beta genomic deletions of SWR mice (V beta a), the wild-type TCR allele of C57Bl/10 (B10) mice (V beta b), and the intrathymic negative selection processes resulting from cell surface expression of Ek alpha-A q beta or Eb beta-Ek alpha, together with the integrated retroviral genes Mtv-9 originating in B10 mice and Mtv-7 (Mls-1a) from SWR mice. (B10.Ek alpha x SWR)F1 mice developed higher IgG anti-MII Ab titers, but much milder arthritis than (B10.E x B10.Q)F1 mice. Expression of Ek alpha did not change the level of IgG anti-MII Ab nor the degree of susceptibility to collagen-induced arthritis (CIA) in the H-2q/q and H-2b/q progeny of (B10.Ek alpha x B10.Q)F1 x B10.Q matings, indicating that the Mtv-9-reactive, TCR V beta 5+, and V beta 11+ T cells are not critical to CIA. Among bovine type II collagen-immunized (B10.Ek alpha x SWR)F1 x SWR backcross mice: 1) arthritis severity is associated with the presence of V beta b (p < or = 0.01) and expression of Ek alpha (p < or = 0.05), but not with the MHC haplotype (b/q vs q/q); 2) regression analysis showed a significant association (R = 0.99) between IgG anti-MII Ab titers and the level of Mtv-7-reactive V beta 6+ T cells that was detectable in the IgG1, but not the IgG2a subclass. The data prompt the speculation that Mtv-7-reactive V beta 6+ (or V beta 7+) T cells in (B10.EK alpha x SWR)F1 x SWR mice express Th2-type properties, and thus contribute to the combination of mild arthritis but high anti-MII Ab titers that characterize mice of SWR heritage.

Collagen-induced arthritis and TCRs in SWR and B10.Q mice expressing an Ek alpha transgene

B10.Ek alpha transgenic mice were mated with H2-E B10.Q and SWR mice. F1 and F1 x parental strain backcross progeny were tested for arthritis and autoimmune reactivity to mouse type II collagen (MII) after immunization with bovine, chick, deer, or human type II collagen. The results were correlated with the H-2 haplotype (b/q vs q/q) and the TCR V beta profile of peripheral blood T cells in each mouse. Hybrid progeny expressed TCR profiles different from either parent because of the TCR V beta genomic deletions of SWR mice (V beta a), the wild-type TCR allele of C57Bl/10 (B10) mice (V beta b), and the intrathymic negative selection processes resulting from cell surface expression of Ek alpha-A q beta or Eb beta-Ek alpha, together with the integrated retroviral genes Mtv-9 originating in B10 mice and Mtv-7 (Mls-1a) from SWR mice. (B10.Ek alpha x SWR)F1 mice developed higher IgG anti-MII Ab titers, but much milder arthritis than (B10.E x B10.Q)F1 mice. Expression of Ek alpha did not change the level of IgG anti-MII Ab nor the degree of susceptibility to collagen-induced arthritis (CIA) in the H-2q/q and H-2b/q progeny of (B10.Ek alpha x B10.Q)F1 x B10.Q matings, indicating that the Mtv-9-reactive, TCR V beta 5+, and V beta 11+ T cells are not critical to CIA. Among bovine type II collagen-immunized (B10.Ek alpha x SWR)F1 x SWR backcross mice: 1) arthritis severity is associated with the presence of V beta b (p &lt; or = 0.01) and expression of Ek alpha (p &lt; or = 0.05), but not with the MHC haplotype (b/q vs q/q); 2) regression analysis showed a significant association (R = 0.99) between IgG anti-MII Ab titers and the level of Mtv-7-reactive V beta 6+ T cells that was detectable in the IgG1, but not the IgG2a subclass. The data prompt the speculation that Mtv-7-reactive V beta 6+ (or V beta 7+) T cells in (B10.EK alpha x SWR)F1 x SWR mice express Th2-type properties, and thus contribute to the combination of mild arthritis but high anti-MII Ab titers that characterize mice of SWR heritage.

Exacerbation of collagen-induced arthritis in rats by rat cytomegalovirus is antigen-specific

Collagen-Induced Arthritis (CIA) is an experimentally induced and genetically controlled animal model of chronic joint inflammation. In rats, there are informative strain differences in susceptibility to CIA. DA rats (RT1avl) develop severe CIA after immunization with bovine (BII), chick (CII), or homologous rat (RII) type II collagens. In contrast, the MHC-congenic DA. 1N(BN) and WF.1N(BN) rats (RT1n) are relatively resistant to CIA and develop moderate CIA in response to immunization with CII but not BII or RII. We previously found that simultaneous infection with rat cytomegalovirus (RCMV) greatly exacerbates the severity of arthritis that develops in BII-immunized DA rats. To examine the mechanism of RCMV amplification of CIA, the effect of simultaneous infection with RCMV on arthritis and autoimmunity to type II collagen was determined in WF.1N and DA.1N rats after immunization with BII, CII and RII. RCMV increased the incidence of CIA and the level of autoimmunity to type II collagen (skin-testing and IgG antibody titer) selectively in DA.1N and WF.1N rats immunized with CII, but not in littermates immunized with BII, although the transient reversal of CD4+/CD8+ mononuclear cell ratios in peripheral blood that is associated with RCMV infection occurred equally in both BII- and CII- immunized DA.1N rats. Likewise, RCMV infection moderately increased the levels of anti-RII autoimmunity and arthritis in DA rats sub-optimally immunized with RII but had no consistent effect on either anti-RII immunity or arthritis in RII-immunized DA.1N and WF.1n rats. The data show that RCMV augments arthritis only in rats that are genetically susceptible to CIA and that are appropriately immunized with a species of type II collagen that is arthritogenic for the MHC-haplotype being tested. Two possible mechanisms are suggested by these data: RCMV-associated increases in anti-RII autoimmunity in rats with CIA may result from amino acid sequence homologies between RCMV and type II collagen; alternatively, virus-induced pro-inflammatory cytokines may activate RII-reactive lymphocytes thereby potentiating autoimmunity and arthritis.

Immunomodulation in vivo by the Mycoplasma arthritidis superantigen, MAM

Mycoplasma arthritidis produces a potent superantigen (MAM) that activates specific murine and human T lymphocytes to proliferate and secrete lymphokines. We show here that MAM also influences both T- and B-cell functions in vivo. Lymphocytes from mice injected with MAM exhibit a suppression of proliferative responses to MAM in vitro but only a partial suppression of responses to other mitogens. This T-cell anergy not only decreased contact sensitivity to dinitrofluorobenzene but also prolonged survival of skin transplants. In contrast, B-cell reactivity is increased following in vivo injection of MAM, as evidenced by enhanced antibody responses to sheep red blood cells and ovalbumin. Also, there is a marked decrease in the ability of splenocytes from MAM-injected mice to produce interleukin-2 (IL-2) but a marked increase in their ability to produce IL-4 and IL-6. The combined results suggest that MAM induces a lymphokine profile that favors activation of B-cell functions, with a resulting potential for triggering of autoimmune disease.

Effects of gold sodium thiomalate, cyclosporin A, cyclophosphamide, and placebo on collagen-induced arthritis in rats

The prophylactic and therapeutic effects of gold sodium thiomalate, cyclosporin A, cyclophosphamide, and placebo on collagen-induced arthritis (CIA) were evaluated in DA rats. Prophylactic treatment with cyclosporin A and cyclophosphamide suppressed the arthritis incidence, clinical inflammation, destructive bone changes, and development of anti-collagen antibody in DA rats subsequently injected with porcine type-II collagen. Therapeutic treatment with cyclosporin A and cyclophosphamide had a definite suppression on established CIA when started 21 days after the initial collagen injection, but the suppression was less marked than that of prophylactic treatment. Gold had no impact on CIA in DA rats when administered either prophylactically or therapeutically.

Immunogenetics of collagen-induced arthritis in rats. Both MHC and non-MHC gene products determine the epitope specificity of immune response to bovine and chick type II collagens

Seven inbred, RT1-congenic rat strains were immunized with native bovine (BII), porcine (PII), or chick (CII) type II collagen and observed for onset, incidence, and severity of arthritis. Clinical results were compared with IgG reactive with native rat type II collagen (RII) and the purified, renatured cyanogen-bromide peptides of BII, CII, or RII. Immunodominant responses to CB11, CB9,7, and CB12 of RII were identified. Secondary responses to CB8 and CB10 also occurred. Reproducible patterns of peptide reactivity were defined in each strain and reflected both RT1 and non-RT1 genotypes plus the species of immunizing collagen. BN non-RT1 gene products moderated clinical arthritis but increased the levels of reactivity to CB11 in three strains carrying RT1l,n,av1 haplotypes. WF (RT1u) rats were susceptible to collagen-induced arthritis (CIA) and developed very high levels of autoantibodies with dominant responses to rat CB11 after CII injections and to rat CB11 and CB9,7 after BII injections. DA (RT1av1) rats developed the most severe arthritis but had only moderate (total) levels of anti-RII IgG: a broad response to CB11, CB10, and CB9,7 after CII injections but predominantly to CB12 and CB9,7 after BII injections. Three RT1n strains--DA.1N(BN), WF.1N(MAXX), and BN--were resistant to BII-induced CIA but developed mild arthritis after immunization with CII. After BII: BN IgG reacted with CB9-7, CB11, and CB12; DA.1N and WF.1N IgG reacted with CB9,7 and CB12. After CII: BN IgG reacted broadly with CB11, CB9-7, CB12, and CB8; WF.1N IgG reacted to CB9-7, CB11, CB8, and CB12; DA.1N IgG reacted with CB8, CB11, and CB9-7. Thus, selective induction of CIA in BN, WF.1N, and DA.1N rats by CII correlated with serum IgG reactivity to rat CB11, but overall strain results identified no single cyanogen-bromide peptide as expressing the sole "arthritogenic" epitope in CIA.

Immunogenetics of collagen-induced arthritis in rats. Both MHC and non-MHC gene products determine the epitope specificity of immune response to bovine and chick type II collagens

Seven inbred, RT1-congenic rat strains were immunized with native bovine (BII), porcine (PII), or chick (CII) type II collagen and observed for onset, incidence, and severity of arthritis. Clinical results were compared with IgG reactive with native rat type II collagen (RII) and the purified, renatured cyanogen-bromide peptides of BII, CII, or RII. Immunodominant responses to CB11, CB9,7, and CB12 of RII were identified. Secondary responses to CB8 and CB10 also occurred. Reproducible patterns of peptide reactivity were defined in each strain and reflected both RT1 and non-RT1 genotypes plus the species of immunizing collagen. BN non-RT1 gene products moderated clinical arthritis but increased the levels of reactivity to CB11 in three strains carrying RT1l,n,av1 haplotypes. WF (RT1u) rats were susceptible to collagen-induced arthritis (CIA) and developed very high levels of autoantibodies with dominant responses to rat CB11 after CII injections and to rat CB11 and CB9,7 after BII injections. DA (RT1av1) rats developed the most severe arthritis but had only moderate (total) levels of anti-RII IgG: a broad response to CB11, CB10, and CB9,7 after CII injections but predominantly to CB12 and CB9,7 after BII injections. Three RT1n strains--DA.1N(BN), WF.1N(MAXX), and BN--were resistant to BII-induced CIA but developed mild arthritis after immunization with CII. After BII: BN IgG reacted with CB9-7, CB11, and CB12; DA.1N and WF.1N IgG reacted with CB9,7 and CB12. After CII: BN IgG reacted broadly with CB11, CB9-7, CB12, and CB8; WF.1N IgG reacted to CB9-7, CB11, CB8, and CB12; DA.1N IgG reacted with CB8, CB11, and CB9-7. Thus, selective induction of CIA in BN, WF.1N, and DA.1N rats by CII correlated with serum IgG reactivity to rat CB11, but overall strain results identified no single cyanogen-bromide peptide as expressing the sole "arthritogenic" epitope in CIA.

Encephalocraniocutaneous lipomatosis and the Proteus syndrome: distinct entities with overlapping manifestations

We have studied three children with cutaneous (epidermal nevi), subcutaneous (lipomas, plantar skin thickening), vascular (hemangioma, lymphangioma), skeletal (osteoma, exostosis, localized hypertrophy), and neurological (hydrocephaly, lissencephaly, partial agenesis of the corpus callosum) developmental defects associated with the Proteus syndrome and related hamartoneoplastic conditions. We compared our findings in these three patients with those of 50 others with Proteus syndrome and nine with encephalocraniocutaneous lipomatosis (ECCL) reported in the literature. We found that Proteus syndrome and ECCL have distinct identities even though some clinical manifestations are shared by both and a few patients have manifestations of both conditions.

Pediatric ABR screening: pass-fail rates in awake versus asleep neonates

The auditory brainstem response (ABR) is commonly used as a neonatal hearing screening tool. The degree to which myogenic and/or movement artifact can confound the ABR in neonates, and the effect this has on screening pass-fail rates, although widely recognized, have not been reported. This study addressed these aspects in a clinical setting. Fifty-two high-risk neonates were screened in various states of activity (asleep, awake-calm, awake-active). Pass-fail rates between asleep and awake babies were significantly different (p less than 0.5), with the awake group displaying a much higher failure rate. There was no significant difference between the awake-calm and awake-active groups. Results indicate that activity state should be noted and considered along with the other factors that are generally blamed for false-positive results in neonatal ABR screenings.

Inhibition of the passive transfer of adjuvant induced arthritis by gold sodium thiomalate

The effect of gold on the passive transfer of adjuvant induced arthritis was studied to determine if gold acted in the donor and/or recipient arms of this model. Joint scores were markedly decreased in rats receiving spleen cells from donor animals treated with gold (p less than 0.01) suggesting that gold injections alters the development and/or function of the spleen cells from these animals which transfer adjuvant induced arthritis. Gold treatment of recipient animals had little effect on subsequent arthritis.