Ethical review of COVID-19 vaccination requirements for transplant center staff and patients.

Transplant centers seeking to increase coronavirus disease 2019 (COVID-19) vaccine coverage may consider requiring vaccination for healthcare workers or for candidates. The authors summarize current data to inform an ethical analysis of the harms, benefits, and individual and societal impact of mandatory vaccination, concluding that vaccine requirements for healthcare workers and transplant candidates are ethically justified by beneficence, net utility, and fiduciary duty to patients and public health. Implementation strategies should mitigate concerns about respect for autonomy and transparency for both groups. We clarify how the same arguments might be applied to related questions of caregiver vaccination, allocation of other healthcare resources, and mandates for non-COVID-19 vaccines. Finally, we call for effort to achieve global equity in vaccination as soon as possible.

Factors Associated With Advanced Colorectal Neoplasia in Patients With CKD.

RATIONALE & OBJECTIVE: The risk of developing colorectal cancer in patients with chronic kidney disease (CKD) is twice that of the general population, but the factors associated with colorectal cancer are poorly understood. The aim of this study was to identify factors associated with advanced colorectal neoplasia in patients with CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Patients with CKD stages 3-5, including those treated with maintenance dialysis or transplantation across 11 sites in Australia, New Zealand, Canada, and Spain, were screened for colorectal neoplasia using a fecal immunochemical test (FIT) as part of the Detecting Bowel Cancer in CKD (DETECT) Study. EXPOSURE: Baseline characteristics for patients at the time of study enrollment were ascertained, including duration of CKD, comorbidities, and medications. OUTCOME: Advanced colorectal neoplasia was identified through a 2-step verification process with colonoscopy following positive FIT and 2-year clinical follow-up for all patients. ANALYTICAL APPROACH: Potential factors associated with advanced colorectal neoplasia were explored using multivariable logistic regression. Sensitivity analyses were performed using grouped LASSO (least absolute shrinkage and selection operator) logistic regression. RESULTS: Among 1,706 patients who received FIT-based screening-791 with CKD stages 3-5 not receiving kidney replacement therapy (KRT), 418 receiving dialysis, and 497 patients with a functioning kidney transplant-117 patients (6.9%) were detected to have advanced colorectal neoplasia (54 with CKD stages 3-5 without KRT, 34 receiving dialysis, and 29 transplant recipients), including 9 colorectal cancers. The factors found to be associated with advanced colorectal neoplasia included older age (OR per year older, 1.05 [95% CI, 1.03-1.07], P<0.001), male sex (OR, 2.27 [95% CI, 1.45-3.54], P<0.001), azathioprine use (OR, 2.99 [95% CI, 1.40-6.37], P=0.005), and erythropoiesis-stimulating agent use (OR, 1.92 [95% CI, 1.22-3.03], P=0.005). Grouped LASSO logistic regression revealed similar associations between these factors and advanced colorectal neoplasia. LIMITATIONS: Unmeasured confounding factors. CONCLUSIONS: Older age, male sex, erythropoiesis-stimulating agents, and azathioprine were found to be significantly associated with advanced colorectal neoplasia in patients with CKD.

Association Between Side of Living Kidney Donation and Post-Transplant Outcomes.

Background: Right-sided living donor kidneys have longer renal arteries and shorter veins that make vascular anastomosis more challenging. We sought to determine whether recipients of right-sided living donor kidneys have worse outcomes than left-sided kidney recipients. Methods: An observational analysis of the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) was undertaken. We used adjusted logistic regression to determine the association between side and delayed graft function (DGF) and time-stratified adjusted cox regression models for graft and patient survivals. Results: Between 2004 and 2018, 4,050 living donor kidney transplants were conducted with 696 (17.2%) using right kidneys. With reference to left kidneys, the adjusted OR (95% CI) for DGF was 2.01 (1.31-3.09) for recipients with right kidneys. Within 30 days, 46 allografts (1.4%) were lost, with major causes of overall graft loss being technical, primary non-function and death. Recipients of right donor kidneys experienced a greater risk of early graft loss (aHR 2.02 [95% CI 1.06-3.86], p = 0.03), but not beyond 30 days (aHR 0.97 [95% CI 0.80-1.19], p = 0.8]). Conclusion: Technical challenge is the most common cause of early graft loss. The risk of early graft loss among recipients who received right kidneys is doubled compared to those who received left living donor kidneys.

One-Time Fecal Immunochemical Screening for Advanced Colorectal Neoplasia in Patients with CKD (DETECT Study).

BACKGROUND: In patients with CKD, the risk of developing colorectal cancer is high and outcomes are poor. Screening using fecal immunochemical testing (FIT) is effective in reducing mortality from colorectal cancer, but performance characteristics of FIT in CKD are unknown. METHODS: To determine the detection rates and performance characteristics of FIT for advanced colorectal neoplasia (ACN) in patients with CKD, we used FIT to prospectively screen patients aged 35-74 years with CKD (stages 3-5 CKD, dialysis, and renal transplant) from 11 sites in Australia, New Zealand, Canada, and Spain. All participants received clinical follow-up at 2 years. We used a two-step reference standard approach to estimate disease status. RESULTS: Overall, 369 out of 1706 patients who completed FIT (21.6%) tested positive; 323 (87.5%) underwent colonoscopies. A total of 1553 (91.0%) completed follow-up; 82 (4.8%) had died and 71 (4.2%) were lost. The detection rate of ACN using FIT was 6.0% (5.6%, 7.4%, and 5.6% for stages 3-5 CKD, dialysis, and transplant). Sensitivity, specificity, and positive and negative predictive values of FIT for ACN were 0.90, 0.83, 0.30, and 0.99, respectively. Of participants who underwent colonoscopy, five (1.5%) experienced major colonoscopy-related complications, including bowel perforation and major bleeding. CONCLUSIONS: FIT appears to be an accurate screening test for patients with CKD, such that a negative test may rule out the diagnosis of colorectal cancer within 2 years. However, the risk of major complications from work-up colonoscopy are at least ten-fold higher than in the general population.

Recurrent glomerulonephritis after kidney transplantation: risk factors and allograft outcomes.

Recurrent glomerulonephritis after kidney transplantation is a feared complication because it is unpredictable and may have a negative impact on graft outcomes. To better understand this we collected data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry accumulated over 30 years. The incidence, risk factors, and outcomes of recurrent glomerulonephritis in transplant recipients were determined using adjusted Cox proportional hazard and competing risk modeling. A total of 6,597 recipients with biopsy-proven glomerulonephritis as the primary cause of end-stage kidney disease were followed for 51,871 person-years (median duration 7.7 years). The four most common types of glomerulonephritis were IgA nephropathy in 2501 patients, focal segmental glomerulosclerosis (FSGS) in 1403, membranous in 376, and membranoproliferative (MPGN) nephropathy in 357 patients. Among these four types, recurrence was reported in 479 of 4637 patients, and of these, 212 lost their allograft due to recurrence. Older age at transplantation (adjusted hazard ratio [per year increase] 0.96 [95% confidence interval 0.95 - 0.97]) was associated with a lower risk of recurrence. Significantly, the five-year graft survival was 30% for recipients with recurrent MPGN and 57-59% for recipients with FSGS, IgA, and membranous nephropathy. Transplant recipients with recurrent disease were twice as likely to lose their allografts compared to those without recurrence (adjusted hazard ratio 2.04 [1.81-2.31]). Thus, recurrent glomerulonephritis remains a significant cause of graft loss in transplant recipients.

What factors influence people's decisions to register for organ donation? The results of a nominal group study.

Rates of transplantation from deceased donors remain low, despite high rates of expressed support. We aimed to better understand this mismatch through determining community attitudes regarding willingness to register as organ donors. Participants were recruited from the general public in four Australian states. Using nominal group techniques, participants ranked factors they believed were important when deciding to register as a deceased donor. Thirteen nominal groups with 114 participants were conducted. 24 factors were ranked by three or more groups. The top ten factors were as follows: saving lives, own decision to donate, family opinions, benefit to recipients, process of organ donation, positive media, positive closure, clarity of consent and body dignity. Other factors included: the consent system, religious and cultural beliefs and incentives for donation. Participant age was a potential modifier of responses. Willingness to register as an organ donor is highly influenced by the altruistic motive of saving lives and improving lives for others; this should be harnessed in communication campaigns. Further research on ethical incentives for organ donation and continued efforts to promote support from religious groups may be useful. Many believe the sole right to consent to donation is theirs and not their families; consent policies reflecting this should be explored.

A role for everolimus in post-transplant encapsulating peritoneal sclerosis: first case report.

Encapsulating peritoneal sclerosis (EPS) is a rare complication of peritoneal dialysis (PD) that carries a high morbidity and mortality. The 'two hit theory' suggests that long term deterioration of the peritoneum combined with intraperitoneal inflammation is needed in the pathogenesis of EPS. For unclear reasons, post transplantation EPS is being increasingly reported in patients previously on PD. To date, there is no proven effective therapy with an absence of randomised controlled trials. Individual case reports and small case series have reported on the use of tamoxifen and corticosteroids for medical management of EPS. The use of everolimus has been reported in a single case, and never in the setting of renal transplantation. Here, we present the first case of post-transplant encapsulating peritoneal sclerosis treated successfully with a combination of everolimus, tamoxifen, low dose corticosteroid and surgery.

Community preferences for the allocation of deceased donor organs for transplantation: a focus group study.

BACKGROUND: Solid organ transplantation is the treatment of choice for those with organ failure, but suitable organs are a limited community resource. Little is known about community preferences for the allocation of those organs. We aimed to determine community preferences for organ allocation and reasons for their choices. METHODS: Participants were recruited from the community in four states in Australia. In focus groups, they identified and discussed attributes that they believed were important for allocating organs to potential recipients. Transcripts were analysed thematically. RESULTS: Thirteen focus groups with 114 participants were conducted. Four major themes emerged: (i) saving and improving the lives; (ii) lowering the risk of lost opportunities; (iii) fairness and (iv) accountability. While happy to discuss general principles, many were not comfortable making organ allocation decisions and were happy to defer to health professionals; this reticence tended to disappear when discussing the use of their own organs. CONCLUSIONS: Participants wanted to save as many lives as possible as well as lower the risk of lost opportunities for those on the waiting list by maximizing the chances of success of every donation. A rational utilitarian ethical model of organ allocation, therefore, appeared to be the dominant framework adopted by the community. Key considerations were compatibility, high chance of peri-operative survival and favouring those with positive lifestyle and self-management choices. Communication between the transplant community and general community about organ allocation could be undertaken to create trust and shared understanding, which may ultimately increase organ donation rates in the future.

Hypothermic machine perfusion in deceased donor kidney transplantation: a systematic review.

BACKGROUND: Hypothermic machine perfusion (HMP) of kidneys is intended to mitigate the deleterious effects of cold storage on organ quality, particularly when the cold ischemic time is prolonged or the donor is otherwise marginal. The use of HMP has remained controversial; however, a number of randomized controlled trials (RCTs) have recently been conducted to clarify its benefits. METHODS: We undertook a systematic search of the Medline and Embase databases and of the Cochrane Central Register of Controlled Trials. We included only RCTs in the meta-analysis. Outcomes analyzed were the incidence of delayed graft function (DGF), primary nonfunction (PNF), graft loss, and patient death at 1 y. RESULTS: We identified seven RCT trials and subjected them to meta-analysis, including 1353 kidney transplant recipients. Hypothermic machine perfusion significantly reduced the incidence of DGF (risk ratio [RR] 0.83, 95% confidence interval [CI] 0.72-0.96). There was no difference in the incidence of PNF (RR 0.78, 95% CI 0.36-1.68), graft loss at 1 y (RR 0.87, 95% CI 0.64-1.19), and patient death at 1 y (RR 0.91, 95% CI 0.60-1.37) between HMP and donor kidneys preserved using cold storage. CONCLUSIONS: There are few RCT comparing HMP and cold storage of kidneys in deceased donor kidney transplantation. Although these studies are small and heterogeneous in design, HMP appeared to be associated with a reduced incidence of DGF. No difference in the incidence of PNF, graft loss, or patient death at 1 y could be demonstrated.

Factors that influence the decision to be an organ donor: a systematic review of the qualitative literature.

BACKGROUND: Transplantation is the treatment of choice for organ failure, but a worldwide shortage of suitable organs exists. We conducted a systematic review of qualitative studies that explored community attitudes towards living and deceased solid organ donation to inform strategies to improve organ donation rates. METHODS: Medline, Embase, PsycINFO and EconLIT were searched. Qualitative studies that explored community attitudes towards living and deceased solid organ donation were included. A thematic synthesis of the results and conclusions reported by primary authors was performed. RESULTS: Eighteen studies involving 1019 participants were identified. Eight themes emerged. The decision to be an organ donor was influenced by (i) relational ties; (ii) religious beliefs; (iii) cultural influences; (iv) family influences; (v) body integrity; (vi) previous interactions with the health care system-medical mistrust, validity of brain death and fear of early organ retrieval; (vii) the individual's knowledge about the organ donation process and (viii) major reservations about the process of donation, even in those who support organ donation. CONCLUSIONS: This review of qualitative studies highlights that seemingly intractable factors, such as religion and culture, are often tied in with more complex issues such as a distrust of the medical system, misunderstandings about religious stances and ignorance about the donation process. Intervention that could be considered includes culturally appropriate strategies to engage minority groups, especially through religious or cultural leaders, and more comprehensively available information about the donation process and its positive outcomes.

Community Preferences for the Allocation & Donation of Organs--the PAraDOx Study.

BACKGROUND: Transplantation is the treatment of choice for people with severe organ failure. However, demand substantially exceeds supply of suitable organs; consequently many people wait months, or years to receive an organ. Reasons for the chronic shortage of deceased organ donations are unclear; there appears to be no lack of 'in principle' public support for organ donation. METHODS/DESIGN: The PAraDOx Study examines community preferences for organ donation policy in Australia. The aims are to 1) determine which factors influence decisions by individuals to offer their organs for donation and 2) determine the criteria by which the community deems the allocation of donor organs to be fair and equitable. Qualitative and quantitative methods will be used to assess community preferences for organ donation and allocation.Focus group participants from the general community, aged between 18-80, will be purposively sampled to ensure a variety of cultural backgrounds and views on organ donation. Each focus group will include a ranking exercise using a modified nominal group technique. Focus groups of organ recipients, their families, and individuals on a transplant waiting list will also be conducted.Using the qualitative work, a discrete choice study will be designed to quantitatively assess community preferences. Discrete choice methods are based on the premise that goods and services can be described in terms of a number of separate attributes. Respondents are presented with a series of choices where levels of attributes are varied, and a mathematical function is estimated to describe numerically the value respondents attach to different options. Two community surveys will be conducted in approximately 1000 respondents each to assess community preferences for organ donation and allocation. A mixed logit model will be used; model results will be expressed as parameter estimates (ß) and the odds of choosing one option over an alternative. Trade-offs between attributes will also be calculated. DISCUSSION: By providing a better understanding of current community preferences in relation to organ donation and allocation, the PAraDOx study will highlight options for firstly, increasing the rate of organ donation and secondly, allow for more transparent and equitable policies in relation to organ allocation.

Colour duplex ultrasound accurately identifies focal stenoses in dysfunctional autogenous arteriovenous fistulae.

AIMS: The aims of this study is to correlate colour duplex ultrasonography (US) with contrast fistulography for the detection of functional stenoses in the autogenous AVF (arterio-venous fistula) circuit. METHODOLOGY: Colour duplex US scans of 93 dialysis patients with dysfunctional AVF were compared with fistulograms performed within 6 weeks of the US. The AVF circuit was divided into six zones: inflow artery; anastomosis; distal vein; mid vein; proximal vein; and central vein. Colour duplex US and fistulogram images/reports were independently re-reported for stenoses in each fistula zone by two trained clinicians blinded to the outcomes. For each fistula, only zones examined by both modalities were included in the study. Kappa analysis of the results was performed to assess the accuracy of colour duplex US in the dysfunctional AVF circuit. RESULTS: Most AVF studied were radio-cephalic (59%) or brachio-cephalic (22%). Stenoses identified within the AV circuit in order of frequency were: distal vein (41), mid vein (23), arterial (12), proximal vein (7) and anastomosis (3). The interval between US and fistulogram studies was 33 + or - 29 days. Congruence of results between US and fistulograms ranged from 85% to 96%, depending on the zone examined. Kappa analysis of this US versus fistulogram data was also moderate to good, ranging from 0.72 and 0.91. CONCLUSIONS: Colour duplex US provides an accurate diagnostic assessment of a dysfunctional autogneous AVF, and is an important planning tool for subsequent open or endovascular intervention. It is particularly accurate in the peri-anastomotic area of the fistula which harbours the majority of fistula problems.

Beware the band adhesion: an unexpected cause of double obstruction following intraperitoneal kidney transplantation.

Small bowel obstruction (SBO) following intraperitoneal renal transplantation, either solitary or due to simultaneous pancreas-kidney transplantation, is a known complication. While SBO is most commonly due to adhesions, there have been documented cases of internal herniation following simultaneous pancreas-kidney transplantation with enteric drainage due to the formation of a mesenteric defect. We present a unique complication in which the transplant ureter has caused strangulation and necrosis of a length of small intestine. The transplant ureter was mistaken for a band adhesion and divided. Post-operative anuria signalled this difficult diagnosis. Subsequent re-look laparotomy and ureteric reimplantation with Boari flap were required. Therefore, it is important to consider the ureter as a cause of internal herniation in kidney transplant patients and recognize that a band adhesion within the pelvis may in fact be the transplant ureter, obstructing a loop of small intestine beneath its course.

Health-Related Quality of Life in People Across the Spectrum of CKD.

INTRODUCTION: People with chronic kidney disease (CKD) experience reduced quality of life (QoL) because of the high symptom and treatment burden. Limited data exist on the factors associated with overall and domain-specific QoL across all CKD stages. METHODS: Using data from a prospective, multinational study (Australia, New Zealand, Canada, and Spain) in 1696 participants with CKD, we measured overall and domain-specific QoL (pain, self-care, activity, mobility, anxiety/depression) using the EuroQoL, 5 dimension, 3 level. Multivariable linear regression and logistic modeling were used to determine factors associated with overall and domain-specific QoL. RESULTS: QoL for patients with CKD stages 3 to 5 (n = 787; mean, 0.81; SD, 0.20) was higher than in patients on dialysis (n = 415; mean, 0.76; SD, 0.24) but lower than in kidney transplant recipients (n = 494; mean, 0.84; SD, 0.21). Factors associated with reduced overall QoL (ß [95% confidence intervals]) included being on dialysis (compared with CKD stages 3-5: -0.06 [-0.08 to -0.03]), female sex (-0.03 [-0.05 to -0.006]), lower educational attainment (- 0.04 [-0.06 to -0.02), lacking a partner (-0.04 [-0.06 to -0.02]), having diabetes (-0.05 [-0.07 to -0.02]), history of stroke (-0.09 [-0.13 to -0.05]), cardiovascular disease (-0.06 [-0.08 to -0.03]), and cancer (-0.03 [-0.06 to -0.009]). Pain (43%) and anxiety/depression (30%) were the most commonly affected domains, with dialysis patients reporting decrements in all 5 domains. Predictors for domain-specific QoL included being on dialysis, presence of comorbidities, lower education, female sex, and lack of a partner. CONCLUSIONS: Being on dialysis, women with CKD, those with multiple comorbidities, lack of a partner, and lower educational attainment were associated with lower QoL across all stages of CKD.

Overexpression of indoleamine dioxygenase in rat liver allografts using a high-efficiency adeno-associated virus vector does not prevent acute rejection.

The aim of this study was to evaluate the ability of local overexpression of indoleamine dioxygenase (IDO) to abrogate rat liver transplant rejection by the use of an adeno-associated virus vector [recombinant adeno-associated virus 2/8 (rAAV2/8)] to deliver the transgene to the allograft prior to transplantation. A green fluorescent protein (GFP)-expressing vector [recombinant adeno-associated virus 2/8-liver-specific promoter 1-enhanced green fluorescent protein (rAAV2/8-LSP1-eGFP)] was used to examine the kinetics of expression and optimal dosing for transduction of Piebald Virol Glaxo (PVG) rat livers. A vector encoding the rat IDO gene (rAAV2/8-LSP1-rIDO) was constructed and tested by its ability to induce tryptophan catabolism and kynurenine production in vitro and in vivo. PVG donor rats were injected, via the portal vein, with rAAV2/8-LSP1-rIDO 2 weeks before transplantation into PVG strain isograft or Lewis (LEW) strain allograft recipients. With the enhanced GFP vector, 29.5% and 47.4% of hepatocytes were found to express GFP at 3 and 6 weeks after injection, respectively. In untransplanted PVG animals, the rAAV2/8-LSP1-rIDO vector induced, 3 weeks after administration, a 1.8-fold increase (P = 0.0161) in liver IDO activity, which was associated with a fall in serum tryptophan to 0.5 times the baseline level (P < 0.001). PVG recipients of PVG liver isografts pretreated with the IDO-expressing vector had a 45% lower level of serum tryptophan than recipients of isografts pretreated with the GFP-expressing vector (P = 0.03). LEW recipients of PVG liver allografts pretreated with the rat IDO vector had a median survival time of 12 days, whereas recipients of allografts pretreated with rAAV2/8-LSP1-eGFP had a median survival time of 13 days (P = 0.38). Both groups displayed similar histological features of acute cellular rejection. In conclusion, rAAV2/8 vectors produce highly efficient, though delayed, hepatocyte transduction in vivo and provide a useful gene delivery tool for transplantation models. However, gene delivery using IDO was unsuccessful in prolonging rat liver allograft survival.

Blocking indoleamine dioxygenase activity early after rat liver transplantation prevents long-term survival but does not cause acute rejection.

In a well-characterized rat model of liver transplantation, Piebald Virol Glaxo strain livers are accepted long term in fully mismatched Dark Agouti recipients (tolerance; TOL), but rejected in Lewis recipients (rejection; REJ). Spontaneous tolerance induction is associated with increased interferon-gamma expression, and we examined the role of the interferon-gamma-inducible immunomodulatory enzyme indoleamine dioxygenase (IDO) in this model. On day 3 after transplantation, IDO expression in the spleen of TOL recipients was significantly greater than in REJ. The B-cell population accounted for this early IDO increase. Intragraft expression of IDO increased to the same extent in both TOL and REJ. IDO inhibition for 7 days after transplantation reduced survival, but did not cause acute rejection of the liver in the TOL model. In conclusion, the differential IDO expression by B lymphocytes in the spleen of TOL recipients is not critical for preventing acute rejection.

Heart allograft acceptance induced by anti-CD3 antibody in high-responder rats: effect on foxp3 and cytokine expression and graft infiltration.

The ability of anti-T cell monoclonal antibody G4.18 and polyclonal anti-lymphocyte serum (ALS) to induce long-term graft survival was examined in a high-responder rat heart transplant model. Heterotopic heart allografts were performed from PVG rat strain donors to high-responder Lewis recipients. Immunosuppressive properties of G4.18 and ALS were investigated by immunohistochemistry and PCR analysis. Untreated graft rejection was 8.5 days while treatment with 1 ml ALS prolonged survival to 11.5 days (p=0.01). Treatment with 7 mg/kg G4.18 on days 1 and 3 prolonged survival to >100 days (p=0.002 vs. control and p=0.002 vs. ALS) but did not induce tolerance. Acceptance was associated with marked inhibition of cellular infiltration and inflammatory cytokine expression and only a brief, slight increase in Foxp3:T cell ratio in the graft and no increase in the spleen. In conclusion, G4.18 treatment led to long-term heart transplant survival associated with marked inhibition of early inflammation. Failure to develop tolerance was associated with a lack of early accumulation of Foxp3 cells in the graft or spleen.

Calmodulin localization and its effects on endocytic and phagocytic membrane trafficking in Paramecium multimicronucleatum.

In ciliates, calmodulin (CaM), as in other cells, has multiple functions, such as activation of regulatory enzymes and modulating calcium-dependent cellular processes. By immunogold localization, CaM is concentrated at multiple sites in Paramecium. It is seen scattered over the cytosol, but bound to its matrix, and is concentrated at the pores of the contractile vacuole complexes and with at least three microtubular arrays. It was localized peripheral to the nine-doublet microtubules of the ciliary axonemes. The most striking localization was on the akinetic side only of the cytopharyngeal microtubular ribbons opposite the side where the discoidal vesicles, acidosomes and the 100-nm carrier vesicles bind and move. CaM was also present at the periphery of the postoral microtubular bundles along which the early vacuole moves and was associated with the cytoproct microtubules that guide the spent digestive vacuoles to the cytoproct. It was not found on the membranes of, or in the interior of nuclei, mitochondria, phagosomes, and trichocysts, and was only sparsely scattered over the cytosolic sides of discoidal vesicles, acidosomes, lysosomes, and digestive vacuoles. Together the associations with specific microtubular arrays and the effects of trifluoperazine and calmidazolium indicate that CaM is involved (i) in vesicle transport to the cytopharynx area for vacuole formation and subsequent vacuole acidification, (ii) in early vacuole transport along the postoral fiber, and (iii) in transporting the spent vacuole to the cytoproct. Higher CaM concentrations subjacent to the cell's pellicle and close to the decorated tubules of the contractile vacuole complex may support a role for CaM in ion traffic.