Hospital utilization and costs in a cohort of injection drug users

BACKGROUND

Many injection drug users (IDUs) seek care at emergency departments and some require hospital admission because of late presentation in the course of their illness. We determined the predictors of frequent emergency department visits and hospital admissions among community-based IDUs and estimated the incremental hospital utilization costs incurred by IDUs with early HIV infection relative to costs incurred by HIV-negative IDUs.

METHODS

The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study involving IDUs that began in 1996. Our analyses were restricted to the 598 participants who gave informed consent for our study. We used the participants' responses to the baseline VIDUS questionnaire and, from medical records at St. Paul's Hospital, Vancouver, we collected detailed information about the frequency of emergency department visits, hospital admissions and the primary diagnosis for all visits or hospital stays between May 1, 1996, and Aug. 31, 1999. The incremental difference in hospital utilization costs by HIV status was estimated, based on 105 admissions in a subgroup of 64 participants.

RESULTS

A total of 440 (73.6%) of the 598 IDUs made 2763 visits to the emergency department at St. Paul's Hospital during the study period. Of these 440, 265 (160.2%) made frequent visits (3 or more). The following factors were associated with frequent use: HIV-positive status (seroprevalent: adjusted odds ratio [OR] 1.7, 95% confidence interval [CI] 1.2-2.6; seroconverted during study period: adjusted OR 3.0, 95% CI 1.6-5.7); more than 4 injections daily (adjusted OR 1.5, 95% CI 1.1-2.1); cocaine use more frequent than use of other drugs (adjusted OR 2.0, 95% CI 1.2-3.6); and unstable housing (adjusted OR 1.5, 95% CI 1.1-2.2). During the study period 210 of the participants were admitted to hospital 495 times; 118 (56.2%) of them were admitted frequently (2 or more admissions). The 2 most common reasons for admission were pneumonia (132 admissions among 79 patients) and soft-tissue infections (cellulitis and skin abscess) (90 admissions among 59 patients). The following factors were independently associated with frequent hospital admissions: HIV-positive status (seroprevalent: adjusted OR 5.4, 95% CI 3.4-8.6; seroconverted during study period: adjusted OR 2.9, 95% CI 1.4-6.0); and female sex (adjusted OR 1.8, 95% CI 1.1-3.1). The incremental hospital utilization costs incurred by HIV-positive IDUs relative to the costs incurred by HIV-negative IDUs were $1752 per year.

INTERPRETATION

Hospital utilization was significantly higher among community-based IDUs with early HIV disease than among those who were HIV negative. Much of the hospital use was related to complications of injection drug use and may be reduced with the establishment of programs that integrate harm reduction strategies with primary care and addiction treatment.

Involvement of ITF2 in the transcriptional regulation of melanogenic genes

In response to agouti signal protein, melanocytes switch from producing eumelanin to pheomelanin concomitant with the down-regulation of melanogenic gene transcription. We previously reported that a ubiquitous basic helix-loop-helix transcription factor, known as ITF2, is up-regulated during this switch, and we now report that treatment of melanocytes with melanocyte-stimulating hormone down-regulates expression of ITF2. To more fully characterize the involvement of ITF2 in regulating melanogenic gene transcription, ITF2 sense or antisense constructs were introduced into melan-a melanocytes. Gene and protein expression analyses and luciferase reporter assays using promoters from melanogenic genes showed that up-regulation of ITF2 suppressed melanogenic gene expression as well as the expression of Mitf, a melanocyte-specific transcription factor. In addition, stable ITF2 sense transfectants had significant reductions in pigmentation and a less dendritic phenotype compared with mock transfectants. In contrast, ITF2 antisense-transfected melanocytes were more pigmented and more dendritic. These results demonstrate that up-regulation of ITF2 during the pheomelanin switch is functionally significant and reveal that differential expression of a ubiquitous basic helix-loop-helix transcription factor can modulate expression of melanogenic genes and the differentiation of melanocytes.

Two different lateral amygdala cell populations contribute to the initiation and storage of memory

Single-cell activity was recorded in the dorsal subnucleus of the lateral amygdala (LAd) of freely behaving rats during Pavlovian fear conditioning, to determine the relationship between neuronal activity and behavioral learning. Neuronal responses elicited by the conditioned stimulus typically increased before behavioral fear was evident, supporting the hypothesis that neural changes in LAd account for the conditioning of behavior. Furthermore, two types of these rapidly modified cells were found. Some, located in the dorsal tip of LAd, exhibited short-latency responses (<20 ms) that were only transiently changed. A second class of cells, most commonly found in ventral regions of LAd, had longer latency responses, but maintained enhanced responding throughout training and even through extinction. These anatomically distinct cells in LAd may be differentially involved in the initiation of learning and long-term memory storage.

What did we learn about interdisciplinary collaboration in institutions?

The Interdisciplinary Generalist Curriculum (IGC) Project significantly advanced collaboration in the development of medical school curricula. As primary care faculty began to work together they encountered and overcame many challenges inherent in this new process. Inclusion of other faculty and departments, as well as dedicated support from the deans' offices, became necessary to the success of the projects. The continuation of successful collaborative projects in the medical school environment requires a common commitment of faculty, students, department chairs, and the dean's office; protected time; and involvement of faculty from other disciplines. This article outlines initial models of collaboration implemented in the IGC Project, followed by a description of the expected and unexpected outcomes of these collaborative efforts, and a discussion of the emergence of new ways of collaborating, with recommendations for successful collaborative efforts.

What did we learn about the impact on university-based faculty?

Meeting the objectives and requirements of the Interdisciplinary Generalist Curriculum (IGC) Project had positive and negative effects on the university-based basic science and clinical faculty, which have been divided into four categories: boundary issues, collaboration, teaching, and development. The specific experiences of two schools, the University of California, San Francisco, School of Medicine and the Joan C. Edwards School of Medicine at Marshall University, are compared against the experiences of the ten schools as documented in the IGC Project external evaluation team's final report. Boundary issues regarded as negative effects of the IGC Project included perceived encroachment on the time devoted to basic science education, loss of the unique identity of the university-based faculty as academicians, and reduced prominence of subspecialist clinical faculty. Effects of the IGC Project in the other areas were, for the most part, positive. The increased collaboration yielded a net benefit to the university-based faculty at large. The clinical faculty experienced more opportunities to teach. Introduction of teacher development programs were of benefit to both clinical and basic science faculty. The other arm of development, professional development, was evidenced by increased stature and promotions of IGC faculty directors. In conclusion, changes within the university-based faculty occurred in stages as faculty realized that the design of the IGC Project enhanced the educational experience of the students.

Bilateral effect of a unilateral occlusal splint on the expression of myosin heavy-chain isoforms in rat deep masseter muscle

Many studies have shown that various myosin isoforms are involved in muscle contraction. A search for specific antibodies directed against the myosin heavy chain (MHC) resulted in the identification of at least two main classes, referred to as MHC type I and type II. In this study, immunohistology and gel electrophoresis were used to determine the proportion of MHC isoforms in rat deep masseter muscle at different times after the insertion of an unilateral occlusal splint. An increasing proportion of MHC type I isoforms was found in both deep masseters soon after splinting, and this trend continued until 7 days after splint insertion. The type I fibres were clearly distributed on either side of the central axis of the muscle. At 15 days, a significant decrease in the percentage of the type IIb MHC isoform was observed on the occlusal splint side compared to the contralateral side. After 30 days of unilateral splinting, the proportion of type IIb fibres on the splint side returned to baseline whereas on the contralateral side there was an increase in the proportion of this type. The results suggest an initial adaptation after the unilateral occlusal disturbance in which muscles of both sides react in the same way; later, the muscles of each side adapt their expression of MHC isoforms according to altered functional demand.

A randomized, double-blind, placebo-controlled, dose-ranging study to compare the efficacy and safety of three doses of botulinum toxin type A (Dysport) with placebo in upper limb spasticity after stroke

BACKGROUND AND PURPOSE

We sought to define an effective and safe dose of botulinum toxin type A (Dysport) for the treatment of upper limb muscle spasticity due to stroke.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled, dose-ranging study. Patients received either a placebo or 1 of 3 doses of Dysport (500, 1000, 1500 U) into 5 muscles of the affected arm. Efficacy was assessed periodically by the Modified Ashworth Scale and a battery of functional outcome measures.

RESULTS

Eighty-three patients were recruited, and 82 completed the study. The 4 study groups were comparable at baseline with respect to their demographic characteristics and severity of spasticity. All doses of Dysport studied showed a significant reduction from baseline of muscle tone compared with placebo. However, the effect on functional disability was not statistically significant and was best at a dose of 1000 U. There were no statistically significant differences between the groups in the incidence of adverse events.

CONCLUSIONS

The present study suggests that treatment with Dysport reduces muscle tone in patients with poststroke upper limb spasticity. Treatment was effective at doses of Dysport of 500, 1000, and 1500 U. The optimal dose for treatment of patients with residual voluntary movements in the upper limb appears to be 1000 U. Dysport is safe in the doses used in this study.

Spectroscopic evidence for the tricapped trigonal prism structure of semiconductor clusters

We have obtained photoelectron spectra (PES) for silicon cluster anions with up to 20 atoms. Efficient cooling of species in the source has allowed us to resolve multiple features in the PES for all sizes studied. Spectra for an extensive set of low-energy Si(-)(n) isomers found by a global search have been simulated using density functional theory and pseudopotentials. Except for n = 12, calculations for Si(-)(n) ground states agree with the measurements. This does not hold for other plausible geometries. Hence PES data validate the tricapped trigonal prism morphologies for medium-sized Si clusters.

Long-term follow-Up of an infant with thyrotoxicosis due to germline mutation of the TSH receptor gene (Met453Thr)

A 18-year clinical follow-up period in a male patient with a germline TSH-R gene mutation (Met453Thr) is described. Nonautoimmune thyrotoxicosis was diagnosed at the age of 7 months. The patient had exophthalmus, failure to thrive, advanced bone age and no goiter. Long-term antithyroid drug treatment (ATD) was necessary during childhood. At the age of 7 years he developed a goiter. Subtotal thyroidectomy was performed at the age of 9 years, followed by repeated ablative radiotherapy at the age of 9.5-13 years due to a toxic multinodular goiter. After 13 years ATD could be discontinued and the patient was euthyroid until 16 years of age, where L-thyroxine substitution had to be started. The exophthalmus diminished, and had disappeared at the age of 18 years, when CT scan of the orbit was performed.

CONCLUSION

TSH-R mutation must be considered in early nonautoimmune thyrotoxicosis. A very aggressive treatment strategy is necessary.

BBID: the biological biochemical image database

The Biological Biochemical Image Database is a WWW accessible relational database of archived images from research articles that describe regulatory pathways of higher eukaryotes. Pathway information is annotated and can be queried in the study of complex gene expression. In this way, complex regulatory pathways can be tested empirically in an efficient manner in the context of large-scale gene-expression systems.

Effect of different promoters on immune responses elicited by HIV-1 gag/env multigenic DNA vaccine in Macaca mulatta and Macaca nemestrina

pCMV-NL(Deltapol) and pAKV-NL(Deltapol) expressed human immunodeficiency virus type 1 (HIV-1) gag and env under the regulation of the human cytomegalovirus (CMV) immediate-early (IE) promoter/enhancer and the endogenous AKV murine leukemia viral long terminal repeat (LTR), respectively. Analysis of the immune responses elicited by direct DNA injection of pCMV-NL(Deltapol) and pAKV-NL(Deltapol) in macaques indicated that generation of the humoral and T-cell proliferative responses correlated directly with the promoter strength of the vaccine DNAs. In Macaca mulatta, pCMV-NL(Deltapol) generated stronger humoral responses and T-cell proliferative responses to Gag and Env using less DNA and fewer number of injections than pAKV-NL(Deltapol). Similarly, in Macaca nemestrina pCMV-NL(Deltapol) elicited high humoral responses, which persisted long-term and were boostable. Injection of large amounts of pAKV-NL(Deltapol), in general, failed to produce antibody levels comparable to pCMV-NL(Deltapol). However, injection of a control animal with large amounts of vector DNA produced a generalized enzyme-linked immunosorbent assay (ELISA) reactivity to HIV-1. The results indicated that generation of high immune responses to HIV-1 cannot be achieved by increasing the vaccine DNA dose and may require high protein expression from the DNA by including a strong promoter or by the use of other boosting agents. Furthermore, safety concerns may arise with increasing the DNA dose that could need additional investigation.

Direct observation of the dynamics of electronic excitations in molecules and small clusters

Femtosecond time-resolved photoelectron spectroscopy is applied to study relaxation paths of excited states of mass-selected negatively charged clusters. As a first example, the lifetime of an excited state of the carbon trimer anion is measured directly. In addition, the mechanism of the decay, i.e., the configurations of the participating electronic states, is determined from the photoelectron spectra. In general, this method can be used to study all kinds of electronic excitation and relaxation processes in mass-selected nanoparticles.

Pnictides as symmetrically bridging ligands in novel neutral complexes

The reaction of [LWCl] (3) [L = N(CH2CH2NiPr)3] with LiE(SiMe3)2 (E = P, As, Sb) yields the novel, neutral pnictido-bridged complexes [LW = E = WL] (5-7). By following the reaction, which starts from the LiP-(SiMe3)2 derivative, by 31P NMR spectroscopy, the formation of an intermediate with a terminal pnictido ligand can be ruled out. The paramagnetic complexes 5-7 are comprehensively spectroscopically characterised. The X-ray structure analysis of the heterocumulenes 5-7 reveals a linear structure in which the two W-"tren" units bind to the central pnictido atom in a staggered conformation ["tren" = tren-based ligand; tren = tris(2-aminoethyl)-amine. When N2 is used as the inert gas in the synthesis of the starting material [N(CH2CH2NNp)3WCl] [Np = CH2C-(CH3)3], the complex [[N(CH2CH2NNp)3]W2(mu, eta 1: eta 1-N2)] (4) is formed as a side product. Complex 4 possesses a hydrazido(4-) (N2(4-)) ligand connected by two tungsten-"tren" moieties.

Intramyocardial electrogram recordings (IMEG) for diagnosis of cellular and humoral mediated cardiac allograft rejection

OBJECTIVE

The purpose of this study was to prove the reliability of intramyocardial electrogram (IMEG) recordings for diagnosis and treatment monitoring of (1) cellular and (2) humoral mediated allograft rejection after heart transplantation.

MATERIAL AND METHODS

Fifteen beagle dogs underwent heterotopic neck-heart transplantation. Eight of them were previously sensitized through several skin transplantations. IMEG recordings were performed daily. Donor-specific antibodies (IgG, IgM) were determinated in serum daily. Transmyocardial biopsies were performed every two days.

RESULTS

In the sensitized group (group I) accelerated rejection occurred under triple drug immunosuppression with cyclosporine A, azathioprine, and cortisone on the fifth postoperative day (range: 4th-5th). All episodes were detected through IMEG diagnosis. In each case rejection could be treated successfully. In the cellular mediated group (group II), the average sensitivity for rejection diagnosis of a single lead was 24% for the unipolar and 42% for the bipolar leads. When the voltages of different leads were summed up the sensitivity rose to 36% (3 unipolar), 81% (3 bipolar) and 100% (all leads). During rejection therapy the IMEG recovered within 24-48 hours.

CONCLUSION

The IMEG detects cellular and humoral mediated rejection early and with high reliability. The rejection-related changes of grade 2/3a rejection in IMEG seem to follow a Ofocal patternO similar to the histology. Therefore the recording of several, preferably bipolar, electrode configurations appears to enhance diagnostic reliability.

Urinary choloyl-PABA excretion in diagnosing small intestinal bacterial overgrowth: evaluation of a new noninvasive method

The synthetic substrate cholyl-PABA, developed by conjugating cholic acid with paraaminobenzoic acid, is hydrolyzed by the bacterial enzyme cholyl hydrolase to release free PABA. This study aimed to evaluate whether quantitating urinary excretion of PABA after oral administration of cholyl-PABA can detect small intestinal bacterial overgrowth. In the first phase, investigations were performed on 10 healthy volunteers to study the dynamics of urinary excretion of PABA and any adverse reactions after oral administration of 1.2 g of cholyl-PABA. Another 10 healthy volunteers and 25 adult patients with various gastrointestinal disorders participated in the second phase, where the urinary cholyl-PABA test was compared to the [14C]xylose breath test (XBT). The upper limit of normal levels of urinary PABA excretion at the end of 4 h was 1.1% of the administered dose of cholyl-PABA. The urinary PABA excretion after 4 hr [median (range), in percentage] in the XBT-positive group was 1.6 (0.6-35.0), which was significantly higher than those in the XBT-negative group [0.7 (0.4-1.8)] and the healthy controls [0.7 (0.2-1.1)]. The agreement between the XBT and the urinary cholyl-PABA test was 85.7% (P < 0.01). No adverse effect was noted. In conclusion, the urinary cholyl-PABA test offers a simple, safe, noninvasive, and rapid method for diagnosing small intestinal bacterial overgrowth and warrants further clinical evaluation.

HIV-1 infects and alters immune function of a monocyte subset expressing low CD14 surface phenotype

Monocytes represent a leukocyte subset that express high levels of CD14 on their surface (CD14-high). These cells play a critical role in the pathogenesis of HIV-1 infection. In the present study, we have identified a monocyte subset expressing an extremely low level of CD14 (CD14-low), and examined their susceptibility to HIV-1 infection. Phenotypic analysis by flow cytometry of these cells revealed a low level of CD4, but the absence of CD3, CD14, CD19, and CD83 surface markers. Both CD14-low and CD14-high cell populations expressed CD13 and CD33 markers on their surface, suggesting these cells to be of myeloid origin. Morphologically, CD14-low cells were indistinguishable from CD14-high cells. CD14-low cells were susceptible to infection with a monocytotropic strain of HIV-1 (HIVADA). However, like CD14-high monocytes, CD14-low cells could not be productively infected with a T cell tropic strain of HIV-1 (H9/HTLV(IIIB)). Similar to CD14-high monocytes, CD14-low cells were capable of inducing antigen-stimulated CD4+ T-cell proliferation. HIV-1 infection substantially reduced their ability to induce antigen-stimulated T-cell proliferation. These data indicate that CD14-low cells belong to the monocyte lineage and may play an important role in the immunopathogenesis of HIV-1 infection.

Yttrium-90 DOTATOC: first clinical results

In a pilot study, DOTA-d-Phe(1)-Tyr(3)-octreotide (DOTATOC), which can be labelled with the beta-emitting radioisotope yttrium-90, has recently been used for the treatment of patients with advanced somatostatin receptor-positive tumours who had no other treatment option. The aim of the present study was to elucidate the therapeutic potential of (90)Y-DOTATOC in a larger number of patients employing a standardized treatment protocol. Careful attention was paid to any side-effects (renal and/or haematological toxicity). Of 44 patients with advanced somatostatin receptor-positive tumours of different histology, 29 could be included in the study. The 15 patients who were excluded from the study protocol were assigned to our institution for purely compassionate reasons. The 29 patients who were included received four or more single doses of (90)Y-DOTATOC with ascending activity at intervals of approximately 6 weeks (cumulative dose 6120+/-1347 MBq/m(2)) with the aim of performing an intra-patient dose escalation study. In total, 127 single treatments were given. In eight of these 127 single treatments, total doses of > or = 3700 MBq were administered. In an effort to prevent renal toxicity, two patients received Hartmann-Hepa 8% solution during all therapy cycles, while 13 patients did so during some but not all therapy cycles; in 14 patients no solution was administered during the therapy cycles. The treatment was monitored by computed tomography and indium-111 DOTATOC scintigraphy. Blood parameters were controlled weekly, while tumour markers and liver enzymes were controlled 6-weekly. Of the 29 patients, 24 patients showed no severe renal or haematological toxicity (toxicity < or = grade 2 according to the National Cancer Institute grading criteria). These 24 patients received a cumulative dose of < or = 7400 MBq/m(2). Five patients developed renal and/or haematological toxicity. All of these five patients received a cumulative dose of >7400 MBq/m(2) and had received no Hartmann-Hepa 8% solution during the therapy cycles. Four of the five patients developed renal toxicity; two of these patients showed stable renal insufficiency and two require haemodialysis. Two of the five patients exhibited anaemia (both grade 3) and thrombopenia (grade 2 and 4, respectively). To date, 20 of the 29 patients have shown a disease stabilization, two a partial remission, four a reduction of tumour mass <50% and three a progression of tumour growth. (90)Y-DOTATOC could be a powerful and promising new therapeutic agent for anti-cancer treatment - at least in terms of an adjuvant starting point of the disease. However, problems with toxicity have to be solved. Evaluation of the effect of amino acid infusions (e.g. Hartmann-Hepa 8% solution) during (90)Y-DOTATOC treatments with the aim of reducing renal toxicity is ongoing.

Sensitive assays for isolation and detection of simian foamy retroviruses

Simian foamy viruses (SFVs) are highly prevalent in a variety of nonhuman primate species ranging from prosimians to apes. SFVs possess a broad host range, and human infections can occur by cross-species transfer (W. Heneine et al., Nat. Med. 4:403-407, 1998). Retrovirus screening of potential sources of infection, such as laboratory research animals and simian-derived biological products, could minimize human exposure to SFVs by reducing the risk of potential retrovirus infection in humans. We describe a variety of sensitive assays for SFV isolation and detection which were developed with a prototype strain of SFV serotype 2. The Mus dunni cell line (M. R. Lander and S. K. Chattopadhyay, J. Virol. 52:695-698, 1984) was found to be highly sensitive for SFV production on the basis of various general and specific retrovirus detection assays such as reverse transcriptase assay, transmission electron microscopy, immunofluorescence assay, and Western blotting. A highly sensitive PCR assay was developed on the basis of the sequences in primary SFV isolates obtained from pig-tailed macaques (Macaca nemestrina) and rhesus macaques (Macaca mulatta). Analysis of naturally occurring SFV infection in macaques indicated that analysis by a combination of assays, including both highly sensitive, specific assays and less sensitive, broadly reactive assays, is important for evaluation of retrovirus infection.

Increased winter mortality from acute myocardial infarction and stroke: the effect of age

OBJECTIVES

We examined seasonal variations in mortality from acute myocardial infarction (AMI) and stroke by age using 300,000 deaths in the Canadian Mortality Database for the years 1980 to 1982 and 1990 to 1992.

BACKGROUND

The effect of age on environmental determinants of AMI and stroke is not well understood.

METHODS

Seasonal variations were analyzed by month and for the four seasons (winter beginning in December). A chi-square test was used to test for homogeneity at p < 0.01, and relative risk ratios (RRs) for high and low periods were determined in relation to the overall mean. For each of four age subgroups, the magnitude of the seasonal variation was reported as the difference in mortality between the highest and lowest frequency seasons.

RESULTS

By month, AMI deaths were highest in January (RR = 1.090) and lowest in September (RR = 0.904), a relative risk difference of 18.6%. The seasonal mortality variation in AMI deaths (winter vs. summer) increased with increasing age: 5.8% for <65, 8.3% for 65 to 74, 13.4% for 75 to 84 and 15.8% for >85 years (p < 0.005 for trend). Stroke mortality peaked in January (RR = 1.113) and had a trough in September (RR = 0.914), a relative risk difference of 19.9%. The seasonal variation in stroke mortality also increased with age. Seasonal variations were not seen in those aged <65 years, compared with 11.6% for 65 to 74, 15.2% for 75 to 84 and 19.3% for >85 years (p < 0.005 for trend).

CONCLUSIONS

The elderly demonstrate a greater winter increase in AMI and stroke mortality than younger individuals. An understanding of these seasonal patterns may provide novel avenues for research in cardiovascular disease prevention.

Rubella virus-induced apoptosis varies among cell lines and is modulated by Bcl-XL and caspase inhibitors

Rubella virus (RV) causes multisystem birth defects in the fetuses of infected women. To investigate the cellular basis of this pathology, we examined the cytopathic effect of RV in three permissive cell lines: Vero 76, RK13, and BHK21. Electron microscopy and the TUNEL assay showed that the cytopathic effect resulted from RV-induced programmed cell death (apoptosis) in all three cell lines, but the extent of apoptosis varied among these cells. At 48 h postinfection, the RK13 cell line showed the greatest number of apoptotic cells, the Vero 76 cell line was approximately 3-fold less, and BHK21 had very few. An increased multiplicity of infection and longer time postinfection were required for the BHK21 cell line to reach the level of apoptotic cells in Vero 76 at 48 h. Purified RV induced apoptosis in a dose-dependent fashion, but not UV-inactivated RV or virus-depleted culture supernatant. Specific inhibitors of the apoptosis-specific proteases caspases reduced RV-induced apoptosis and led to higher levels of RV components in infected cells. To address the role of regulatory proteins in RV-induced apoptosis, the antiapoptotic gene Bcl-2 or Bcl-XL was transfected into RK13 cells. Although a high level of Bcl-2 family proteins was expressed, no protection was observed from apoptosis induced by RV, Sindbis virus, or staurosporine in RK13 cells. In BHK21 cells, however, increased expression of Bcl-XL protected cells from apoptosis. The observed variability in apoptotic response to RV of these cell lines demonstrates that programmed cell death is dependent on the unique properties of each cell and may be indicative of how selective organ damage occurs in a congenital rubella syndrome fetus.