Factors associated with Cryptosporidium in men who have sex with men: A systematic review

BACKGROUND

Cryptosporidium parasites are an important cause of diarrhoea globally and sexual transmission may occur in men who have sex with men (MSM). We aimed to systematically review the literature to explore any factors associated with transmission of Cryptosporidium in MSM to provide insight for future guidelines and public health strategies.

METHODS

We searched MEDLINE, Embase, CINAHL and Web of Science for manuscripts published up to July 2023. A primary author conducted an initial screen of abstracts and full text eligibility, and risk of bias was assessed independently by two authors using the Joanna Briggs Institute critical appraisal tools. We used the nine-point synthesis without meta-analysis method to synthesise narrative data. The review was registered on PROSPERO (CRD42023374279).

RESULTS

Six manuscripts were included in the final review from the USA (n = 3), Europe (n = 1) and Australia (n = 2) and were case series (n = 2), cross sectional (n = 2) and case control studies (n = 2) published between 1984 and 2021 and overall there were 1582 cases of Cryptosporidium in MSM. We identified demographic factors (living with HIV, younger age [<30 years old], geographical areas [Southern Europe v Northern Europe], previous Treponema pallidum, previous Entamoeba histolytica) and behavioural factors (recreational drug use, higher number of sexual partners and MSM attending sex on premises venues with spa/sauna) associated with Cryptosporidium in MSM.

CONCLUSIONS

Despite a small number of manuscripts in this review, we identified demographic and behavioural factors associated with Cryptosporidium in MSM. These data will provide insight for public health interventions for future outbreaks of Cryptosporidium in MSM.

Wilderness Medicine Simulation-Based Teaching Program for Medical Students in the UK

INTRODUCTION

The UK undergraduate medicine curriculum provides insufficient opportunities for medical students to explore the field of wilderness medicine, despite interest in the area. The student-led Cambridge University Wilderness Medicine Society devised a low-cost wilderness medicine teaching weekend that can be replicated at other institutions.

METHODS

The weekend course consisted of small-group lessons introducing the roles of the expedition doctor and expedition leader and the assessment and management of acute conditions in remote environments. This was followed by a 3-station circuit to teach the principles of casualty triage, splinting, and construction of rope stretchers. These skills were then practiced in simulations in which participants rotated roles as care providers and patients. Participant confidence was compared before the course and immediately on course completion using the related-samples Wilcoxon signed-ranks test with significance accepted at P<0.05. Usefulness of course content and perceptions of learning were also assessed.

RESULTS

Sixty-one medical students attended the wilderness teaching weekend and completed the structured feedback questionnaires. Participants rated the course highly in terms of usefulness of course content (mean±SD=18.3±1.9, range=12-20) and perceptions of learning (mean±SD=37.6±2.6, range=31-40), with 92% of participants "strongly agreeing" that the course was of high quality. There was an improvement in perceived confidence after course completion (P<0.001).

CONCLUSIONS

We have demonstrated that a teaching program consisting of structured, low-cost "teaching weekends" is a potential solution to the lack of centralized national wilderness medicine teaching and can be integrated, with minimal disruption, into the undergraduate curriculum.

Clinical frailty independently predicts early mortality after ischaemic stroke

BACKGROUND

Clinical frailty is an important syndrome for clinical care and research, independently predicting mortality and rates of institutionalisation in a range of medical conditions. However, there has been little research into the role of frailty in stroke.

OBJECTIVE

This study investigates the effect of frailty on 28-day mortality following ischaemic stroke and outcomes following stroke thrombolysis.

METHODS

Frailty was measured using the Clinical Frailty Scale (CFS) for all ischaemic stroke admissions aged ≥75 years. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). 28-day mortality and clinical outcomes were collected retrospectively. Analysis included both dichotomised measures of frailty (non-frail: CFS 1-4, frail: 5-8) and CFS as a continuous ordinal scale.

RESULTS

In 433 individuals with ischaemic stroke, 28-day mortality was higher in frail versus non-frail individuals (39 (16.7%) versus 10 (5%), P < 0.01). On multivariable analysis, a one-point increase in CFS was independently associated with 28-day mortality (OR 1.03 (1.01-1.05)). In 63 thrombolysed individuals, median NIHSS reduced significantly in non-frail individuals (12.5 (interquartile range (IQR) 9.25) to 5 (IQR 10.5), P < 0.01) but not in frail individuals (15 (IQR 11.5) to 16 (IQR 16.5), P = 0.23). On multivariable analysis, a one-point increase in CFS was independently associated with a one-point reduction in post-thrombolysis NIHSS improvement (coefficient 1.07, P = 0.03).

CONCLUSION

Clinical frailty is independently associated with 28-day mortality after ischaemic stroke and appears independently associated with attenuated improvement in NIHSS following stroke thrombolysis. Further research is needed to elucidate the underlying mechanisms and how frailty may be utilised in clinical decision-making.

Disrupted avoidance learning in functional neurological disorder: Implications for harm avoidance theories

BACKGROUND

Functional neurological disorder (FND) is an elusive disorder characterized by unexplained neurological symptoms alongside aberrant cognitive processing and negative affect, often associated with amygdala reactivity.

METHODS

We examined the effect of negative conditioning on cognitive function and amygdala reactivity in 25 FND patients and 20 healthy volunteers (HV). Participants were first conditioned to stimuli paired with negative affective or neutral (CS +/CS -) information. During functional MRI, subjects then performed an instrumental associative learning task to avoid monetary losses in the context of the previously conditioned stimuli. We expected that FND patients would be better at learning to avoid losses when faced with negatively conditioned stimuli (increased harm avoidance). Multi-echo resting state fMRI was also collected from the same subjects and a robust denoising method was employed, important for removing motion and physiological artifacts.

RESULTS

FND subjects were more sensitive to the negative CS + compared to HV, demonstrated by a reinforcement learning model. Contrary to expectation, FND patients were generally more impaired at learning to avoid losses under both contexts (CS +/CS -), persisting to choose the option that resulted in a negative outcome demonstrated by both behavioural and computational analyses. FND patients showed enhanced amygdala but reduced dorsolateral prefrontal cortex responses when they received negative feedback. Patients also had increased resting state functional connectivity between these two regions.

CONCLUSIONS

FND patients had impaired instrumental avoidance learning, findings that parallel previous observations of impaired action-outcome binding. FND patients further show enhanced behavioural and neural sensitivity to negative information. However, this did not translate to improved avoidance learning. Put together, our findings do not support the theory of harm avoidance in FND. We highlight a potential mechanism by which negative contexts interfere with adaptive behaviours in this under-explored disorder.

Management of systemic AL amyloidosis: recommendations of the Myeloma Foundation of Australia Medical and Scientific Advisory Group

Systemic AL amyloidosis is a plasma cell dyscrasia with a characteristic clinical phenotype caused by multi-organ deposition of an amyloidogenic monoclonal protein. This condition poses a unique management challenge due to the complexity of the clinical presentation and the narrow therapeutic window of available therapies. Improved appreciation of the need for risk stratification, standardised use of sensitive laboratory testing for monitoring disease response, vigilant supportive care and the availability of newer agents with more favourable toxicity profiles have contributed to the improvement in treatment-related mortality and overall survival seen over the past decade. Nonetheless, with respect to the optimal management approach, there is a paucity of high-level clinical evidence due to the rarity of the disease, and enrollment in clinical trials is still the preferred approach where available. This review will summarise the Clinical Practice Guidelines on the Management of Systemic Light Chain (AL) Amyloidosis recently prepared by the Medical Scientific Advisory Group of the Myeloma Foundation of Australia. It is hoped that these guidelines will assist clinicians in better understanding and optimising the management of this difficult disease.

Optimal scheduling to reduce morbidity of involved field radiotherapy with transplantation for lymphomas: A Prospective Australasian Leukaemia and Lymphoma Group Study

This study evaluated delivery of involved field radiotherapy (IFRT) with transplantation for lymphomas timed to minimise toxicity. Patients transplanted for lymphoma had infradiaphragmatic disease irradiated pre-transplant and supradiaphragmatic disease post transplant. A total of 31 patients were studied, with a median follow-up duration of 4 years. Transplant conditioning was according to clinician preference. In all, 14 patients had pre-transplant abdominopelvic IFRT and 19 had post transplant IFRT (including three who had pre-transplant IFRT). Grade III-IV haematological toxicity from pre-transplant IFRT occurred in three patients and from post transplant IFRT in 10 patients. Pre-transplant IFRT had no effect on haematological recovery post transplant, but was associated with a trend towards increased gastrointestinal toxicity (P = 0.094). Pneumonitis due to post transplant thoracic IFRT occurred in one patient. Two patients failed in involved sites after completion of protocol radiotherapy. One case of myelodysplasia has been reported. As sequenced in this study, IFRT was feasible and produced a low incidence of severe pulmonary and haematological toxicities. Patient selection, field size and radiotherapy dose warrant further study.

Allogeneic CD34 selected peripheral stem cell transplant for Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI): rapid haemopoietic and biochemical reconstitution

Severe Maroteaux-Lamy syndrome is usually fatal in teenage or early adult life. Until recently, allogeneic bone marrow transplantation was the only form of enzyme replacement. We report the first successful transplant using CD34 selected, mobilised allogeneic blood cells for an inborn error of metabolism. A busulphan, cyclophosphamide, melphalan and antithymocyte globulin conditioning regimen was used as myeloablative therapy. Allogeneic CD34 selected granulocyte colony-stimulating factor (G-CSF)-mobilised blood cells from a HLA-identical sibling were used for the transplant. Haemopoietic reconstitution occurred on day 10 post-transplant with normal N-acetylgalactosamine-4-sulphatase levels. Infectious and graft-versus-host disease (GVHD) complications were minimal. We suggest that CD34 selected, mobilised allogeneic blood cells are a safe form of enzyme replacement therapy in Maroteaux-Lamy syndrome and should be considered in other metabolic diseases where the benefits of haemopoietic transplantation are proven.

Enhanced levels and enhanced clonogenic capacity of blood progenitor cells following administration of stem cell factor plus granulocyte colony-stimulating factor to humans

Administration of hematopoietic growth factors is being used increasingly to obtain populations of blood progenitor/stem cells (PBPC) for clinical transplantation. Here we examined the effect of combining stem cell factor (SCF ) and granulocyte colony-stimulating factor (G-CSF ) versus G-CSF alone in a randomized clinical study involving 62 women with early-stage breast cancer. In the first patient cohorts, escalating doses of SCF were administered for 7 days with concurrent G-CSF administration. At baseline, levels of progenitor cells in the bone marrow or blood were comparable in the different patient groups. As with administration of G-CSF alone, the combination of SCF plus G-CSF did not alter the wide variation in levels of PBPC observed between individuals and did not alter the selective nature of PBPC release, with preferential release of day-14 granulocyte-macrophage colony-stimulating factor (GM-CFC) versus day-7 GM-CFC. However, SCF acted to sustain the levels of PBPC after cessation of growth factor treatment; levels of PBPC were elevated 100-fold at later timepoints compared with G-CSF alone. In addition, the maximum levels of PBPC observed were increased approximately fivefold at day 5 of growth-factor administration. The increased levels of PBPC resulted in significantly increased levels of PBPC obtained by leukapheresis. In a subsequent patient cohort, 3-days pretreatment with SCF was introduced and followed by 7 days concurrent SCF plus G-CSF. The 3-days pretreatment with SCF resulted in an earlier wave of PBPC release in response to commencement of G-CSF. In addition, maximum PBPC levels in blood and PBPC yield in leukapheresis products were further increased. Unexpectedly however, SCF pretreatment resulted in progenitor cells with enhanced self-generation potential. Recloning assays documented the ability of approximately 30% of primary granulocyte-macrophage (GM) colonies from control cell populations to generate secondary GM colonies (n = 1,106 primary colonies examined). In contrast approximately 90% of GM colonies from PBPC after SCF pretreatment generated secondary clones and 65% generated secondary colonies. The action of SCF was not explicable in terms of altered SCF, GM-CSF, or G-CSF responsiveness, but SCF pretreatment was associated with maximum serum SCF levels at the time G-CSF was commenced. These results show that PBPC populations mobilized by different growth factor regimens can differ in their functional properties and caution against solely considering number of harvested progenitor cells without regard to their function.

Divalent cations and heparin/heparan sulfate cooperate to control assembly and activity of the fibroblast growth factor receptor complex

Polypeptides of the fibroblast growth factor (FGF) family are ubiquitous bioregulators within tissues whose activity is controlled by heparan sulfates within the pericellular matrix. FGF and the ectodomain of their transmembrane tyrosine kinase receptors (FGFR) exhibit heparin-binding domains that when juxtaposed in a FGF middle dotFGFR complex can accommodate a single, potentially bivalent, decameric polysaccharide chain in a ternary complex. Here we show that the interaction of heparin with FGF ligands is not affected by divalent cations. In contrast, the high affinity interaction (apparent Kd = 10 nM) of heparin with FGFR requires Ca2+ or Mg2+ at physiological concentrations. Divalent cations maintain FGFR in a heparan sulfate-dependent state in respect to FGF binding and an FGF- and heparan sulfate-dependent state in respect to autophosphorylation. A model is proposed where divalent cations and heparan sulfate cooperate to maintain FGFR in a conformation that restricts trans-phosphorylation between intracellular kinase domains. The restriction is overcome by FGF or constitutively as a common consequence of diverse mutations in FGFR associated with skeletal and craniofacial abnormalities.

An incremental response to high-dose therapy in multiple myeloma

Results of conventional chemotherapy for multiple myeloma are disappointing. High-dose chemoradiotherapy with auto-transplantation is increasingly reported and some results are encouraging. We report the results of peripheral blood stem cell transplantation (PBSCT) for multiple myeloma at a single institution over a 6-year period. Forty patients, including 18 de novo patients, received debulking chemotherapy consisting of vincristine, adriamycin, and dexamethasone or methyl-prednisolone followed by stem cell mobilization with high-dose cyclophosphamide. Twenty-nine patients received PBSCT following high-dose chemoradiotherapy. Following PBSCT 92% of evaluable patients obtained at least a partial remission and 29% reached complete remission. Objective treatment responses, defined as at least a 50% reduction in serum paraprotein or marrow plasma cells, were observed following each treatment step of debulking chemotherapy, mobilization and PBSCT in 50, 42 and 71% of patients, respectively. The median overall survival from diagnosis in patients transplanted was 50 months and the median overall and progression-free survivals following transplant were 26 and 18 months, respectively. Median follow-up was 28 months. Overall treatment-related mortality was 20% but was significantly lower in de novo vs previously treated patients at 6 and 33% respectively (P = 0.027). De novo patients were more likely to obtain complete remission and had a longer overall survival following transplant but overall survival from diagnosis was similar to previously treated patients. A low serum B2M before mobilization predicted a longer progression-free survival. PBSCT needs to be considered early following diagnosis to maximise treatment response and reduce the high treatment-related mortality seen in heavily pretreated patients. In this treatment program a dose response effect in multiple myeloma was observed possibly suggesting that more intensive therapy than a single transplant may effect greater disease response.