Human vascular endothelial cell adhesion receptors for Plasmodium falciparum-infected erythrocytes: roles for endothelial leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1

The clinical complications associated with severe and cerebral malaria occur as a result of the intravascular mechanical obstruction of erythrocytes infected with the asexual stages of the parasite, Plasmodium falciparum. We now report that a primary P. falciparum-infected erythrocyte (parasitized red blood cell [PRBC]) isolate from a patient with severe complicated malaria binds to cytokine-induced human vascular endothelial cells, and that this adhesion is in part mediated by endothelial leukocyte adhesion molecule 1 (ELAM-1) and vascular cell adhesion molecule 1 (VCAM-1). PRBC binding to tumor necrosis factor alpha (TNF-alpha)-activated human vascular endothelial cells is partially inhibited by antibodies to ELAM-1 and ICAM-1 and the inhibitory effects of these antibodies is additive. PRBCs selected in vitro by sequential panning on purified adhesion molecules bind concurrently to recombinant soluble ELAM-1 and VCAM-1, and to two previously identified endothelial cell receptors for PRBCs, ICAM-1, and CD36. Post-mortem brain tissue from patients who died from cerebral malaria expressed multiple cell adhesion molecules including ELAM-1 and VCAM-1 on cerebral microvascular endothelium not expressed in brains of individuals who died from other causes. These results ascribe novel pathological functions for both ELAM-1 and VCAM-1 and may help delineate alternative adhesion pathways PRBCs use to modify malaria pathology.

A community empowerment approach to the HIV response among sex workers: effectiveness, challenges, and considerations for implementation and scale-up

A community empowerment-based response to HIV is a process by which sex workers take collective ownership of programmes to achieve the most effective HIV outcomes and address social and structural barriers to their overall health and human rights. Community empowerment has increasingly gained recognition as a key approach for addressing HIV in sex workers, with its focus on addressing the broad context within which the heightened risk for infection takes places in these individuals. However, large-scale implementation of community empowerment-based approaches has been scarce. We undertook a comprehensive review of community empowerment approaches for addressing HIV in sex workers. Within this effort, we did a systematic review and meta-analysis of the effectiveness of community empowerment in sex workers in low-income and middle-income countries. We found that community empowerment-based approaches to addressing HIV among sex workers were significantly associated with reductions in HIV and other sexually transmitted infections, and with increases in consistent condom use with all clients. Despite the promise of a community-empowerment approach, we identified formidable structural barriers to implementation and scale-up at various levels. These barriers include regressive international discourses and funding constraints; national laws criminalising sex work; and intersecting social stigmas, discrimination, and violence. The evidence base for community empowerment in sex workers needs to be strengthened and diversified, including its role in aiding access to, and uptake of, combination interventions for HIV prevention. Furthermore, social and political change are needed regarding the recognition of sex work as work, both globally and locally, to encourage increased support for community empowerment responses to HIV.

IgE deposition in brain microvessels and on parasitized erythrocytes from cerebral malaria patients

Postmortem brain tissues of 21 cerebral malaria cases were obtained in Myanmar and Vietnam. The tissues were examined by light microscopy and by an immunohistochemical method. Brain microvessels (capillaries and venules) were examined for the presence of immunoglobulins IgE and IgG, Plasmodium falciparum antigen, and parasitized erythrocytes (PRBC). Deposition of IgE, IgG, and P. falciparum antigen was observed in the microvessels from all specimens examined. Sequestered PRBC in the microvessels were positive for IgG in all 21 cases and for IgE in six cases. In the latter cases, the percentage of microvessels with sequestered PRBC was > 50%, with the frequency of IgE-positive cells ranging from 42% to 52%. In contrast, in five cases that were only weakly positive for IgE, the percentage of microvessels with sequestered PRBC was remarkably low (< 1%). These data indicate that the degree of deposition of IgE in microvessels and on PRBC from cerebral malaria patients correlated with that of PRBC sequestration. As IgE-containing immune complexes are known to induce local overproduction of tumor necrosis factor-alpha (TNF-alpha), a major pathogenic factor in cerebral malaria, IgE may contribute to the pathogenesis of this severe disease.

Comparison of pharmacodynamic intrasubject variability of insulin lispro protamine suspension and insulin glargine in subjects with type 1 diabetes

OBJECTIVE

The objective of the study was to evaluate pharmacodynamic (PD) intrasubject variability of a single, s.c. dose of insulin lispro protamine suspension (ILPS) compared with insulin glargine in subjects with type 1 diabetes mellitus and additionally, to compare the intrasubject variability of pharmacokinetic parameters of both insulins.

DESIGN

This was a single-center, investigator-blinded and subject-blinded, two-arm, parallel, randomized, four-period study. During the replicate visits, subjects received a single s.c. 0.6 U/kg dose of either ILPS or glargine, and underwent 24-h euglycemic glucose clamps.

RESULTS

The intrasubject variabilities of the primary PD parameters, total amount of glucose infused (G(tot)) and maximum glucose infusion rate (GIR; R(max)), were statistically significantly lower for ILPS when compared with glargine (P<0.0001). Least-square (LS) mean estimates for G(tot) and R(max) were 2512.7 mg/kg and 3.740 mg/min per kg respectively for ILPS, and 1291.9 mg/kg and 1.793 mg/min per kg respectively for glargine. The LS mean estimates for G(tot) and R(max) were statistically greater (P=0.0010 and P<0.0001 respectively) for ILPS compared with glargine, suggesting that ILPS had greater 24-h glucose-lowering activity. Glargine demonstrated a flatter GIR-time curve, and ILPS demonstrated a significantly shorter time of maximum GIR (tR(max)) and earlier time to half-maximal GIR before tR(max) and time to half-maximal GIR after tR(max). ILPS administration resulted in significantly greater exposure compared with glargine (area under the baseline-corrected serum concentration versus time curve from time 0 to 24 h (AUC(0-24)): 77 150 vs 53 111 pmol min/l; maximum serum insulin concentration (C(max)): 119 vs 68 pmol/l; ILPS versus glargine respectively), but the intrasubject variabilities for AUC and C(max) were comparable.

CONCLUSION

Although glargine demonstrated a flatter GIR-time profile, the lower PD intrasubject variability of ILPS may provide a more predictable response.

Correlation of viral RNA, alanine aminotransferase, and histopathology in hepatitis C virus-associated hepatitis

BACKGROUND

Hepatitis C virus (HCV) infection is usually monitored by the level of alanine aminotransferase (ALT) and histopathological changes in liver biopsy specimens. However, accumulating data indicate these parameters are not always correlated with disease progression or the response of HCV infection to therapy.

MATERIALS AND METHODS

Using the Amplicor PCR Monitor Test Kit (Roche Diagnostic Systems, Branchburg, NJ), HCV RNA level was measured in 38 patients with positive anti-HCV antibodies and in 21 of those patients after interferon treatment. The grade and stage of histological changes on hematoxylin and eosin-stained sections of liver biopsy specimens were evaluated on a scale of 1 to 4. In each case, the HCV RNA level was compared with the histological grade or stage and level of ALT and statistically analyzed by Student's t-test.

RESULTS

ALT level did not correlate with pretreatment and posttreatment levels of HCV RNA or histopathological changes. However, there was a statistically significant correlation between HCV RNA and histological grade (P,.05).

CONCLUSION

HCV RNA measurement is a better means of determining and monitoring HCV infection than either ALT level or histopathological characteristics and may provide insight into hepatic injury caused by HCV infection even without an invasive liver biopsy.

Antitranspirant-induced increases in leaf water potential increase tuber calcium and decrease tuber necrosis in water-stressed potato plants

Experiments were undertaken with field-grown potato (Solanum tuberosum L.) plants to test the hypothesis that altering leaf:tuber water potential gradients within a plant subjected to low soil moisture will allow greater Ca accumulation in tubers and reverse Ca deficiency-related tuber necrosis. Antitranspirant formulations containing a wax emulsion and a spreader/sticker surfactant increased leaf water potential during a drought episode, significantly reducing the potential gradient that develops between leaf and tuber during a period of stress. Increased leaf water potential in treated plants was associated with decreased leaf Ca and increased tuber Ca. Tuber necrosis was found to be reduced in treated plants, thus increasing tuber quality.

Russell's viper venom fractions and nephrotoxicity

Apparently healthy Wistar rats of body weight 250-300 g were chosen for the experiments. A group of 6 rats were assigned for each fraction. The dose of Russell's viper venom (RVV) fraction used for in vivo experiments was 0.75 microgram/g body weight. Of each batch of 6 rats 3 were sacrificed on the third day and the remaining 3 on the fifth day after the administration of test venom fractions. Daily urine output with proteinuria and serum creatinine were determined on the day they were sacrificed. Kidneys from the rats were also examined under light microscopy after hematoxylin and eosin staining. In the in vitro experiment, kidney slices (1 mm thickness) from normal rat was incubated with RVV fractions of 5 mg/ml concentration. The predominant renal lesions observed in both sets of animal experiments were tubular degeneration and necrosis. The changes were mostly confined to proximal tubules. Glomerular changes were mild. Similar tubulotoxic effects were produced by whole RVV as well as single fractions. Therefore, it is possible that RVV contains a common nephrotoxic (protein) component which is present in all fractions of the venom. The renal damage caused by RVV seemed to be due to both systemic effects (mainly DIC and renal ischemia) and direct tubulotoxic effects of the venom.

Cholera toxin: radio-iodination and uptake by the intestine of sucking rats

1. The chloramine-T procedure was employed to radio-iodinate cholera toxin using Na125I. The procedure was found to be efficient and reproducible. 2. Intragastric injections of both the labelled and the unlabelled toxin produced (a) significant increases in intestinal fluid accumulation as measured by the fluid accumulation ratio; (b) significant increases in cAMP levels; and (c) significant decreases in cAMP-phosphodiesterase activities when compared with the controls suggesting that radio-iodination did not impair the biological activity of the toxin. 3. In vivo uptake studies of the labelled toxin by different parts of the intestine indicated that the uptake by the duodenum and jejunum was high and rapid when compared with the ileum implying that there are more binding sites (or receptor proteins) for cholera toxin in the duodenum and jejunum than in the ileum.

Comparison of combinations of parenteral artemisinin derivatives plus oral mefloquine with intravenous quinine plus oral tetracycline for treating cerebral malaria

A total of 141 cases of strictly defined cerebral malaria were studied in a controlled trial of three regimens: (1) intramuscular artemether plus oral mefloquine, (2) intravenous artesunate plus oral mefloquine, and (3) intravenous quinine (with or without an initial loading dose) plus oral tetracycline. The overall mortalities in each group were 14%, 8.3% and 34.3% respectively. The average parasite clearance time was 27.30 +/- 19.62 hours in regimen 1, 41.84 +/- 17.55 hours in regimen 2, and 47.30 +/- 21.95 hours in regimen 3. No recrudescence was observed in regimens 1 and 2, but 12.1% recrudesced in the third.

1617 SOCS: Surgical On-Call Simulation

Introduction

Simulation is a well-known method of effectively teaching Medical students. The majority of the simulation scenarios are related to Medicine. Surgical simulation is a gap within the curriculum, especially Surgical on-call simulations. To improve this, we ran simulation sessions designed to replicate a General Surgery themed on-call shift that junior doctors should be able to manage. We aimed to improve confidence in clinical prioritisation and confidence in being an on-call Junior doctor, managing the most common on-call surgical tasks.

Method

Groups of 3-4 final year Medical students participated in a 2 hour-long simulated “on-call” shift, throughout the hospital. There were 8 scenarios, which ranged from prescribing to acute clinical scenarios. Students were given bleeps and were called at set times. They had to receive/give handovers and prioritise tasks according to clinical importance. A debrief following the session focussed on prioritisation and highlighted key learning points. The students completed a pre- and post-session questionnaire as assessment.

Results

The percentage of students who felt confident or very confident in the following domains were compared pre- and post-simulation respectively: confidence in clinical prioritisation (17% vs 86%); confidence in prescribing medication (0% vs 14%); confidence in escalation to seniors (33% vs 71%). 87.5% of the participants felt the session was an effective way to learn how to prioritise clinical tasks, and 100% felt this an effective way to learn about common General Surgical queries whilst on-call.

Conclusions

This project demonstrates how simulation is effective in improving confidence in prioritisation and knowledge within clinical practice, especially surgery.

Papillary thyroid carcinoma in struma ovarii: management after surgery

A woman in her 40s presented with a 3-month history of lower abdominal pain and intermenstrual bleeding. Ultrasound of the pelvis disclosed a 4 cm left adnexal mass. An MRI of the pelvis revealed a 2.2×3.6×2.4 cm solid, enhancing left ovarian mass. Due to high suspicion for malignancy, she underwent laparoscopic left salpingo-oophorectomy and resection of the tumour. Histopathology revealed papillary thyroid carcinoma in the background of struma ovarii as confirmed by thyroglobulin and thyroid transcription factor-1 positivity on immunohistochemistry. BRAF mutation analysis was negative. An ultrasound of the thyroid gland showed two low-risk nodules. An iodine-123 whole-body scan showed normal uptake in the thyroid gland. Thyroid-stimulating hormone (TSH) was 1.070 mcIU/mL (0.450-4.500), and thyroglobulin was 6.8 ng/mL (1.5-38.5). We risk-stratified this patient as low risk for recurrence. Risk stratification of malignant struma ovarii is essential to determine suitable thyroid targeting adjuvant therapy and reduce the risk of recurrence.

PSAT276 A Case of Malignant Struma Ovarii: Management After Surgery

Background

Struma ovarii is a highly specialized and extremely rare monodermal ovarian teratoma that comprises 0.3 to 1% of all ovarian tumors. It consists of greater than 50% of mature thyroid tissue that is usually benign, but malignancy has been reported in up to 5- 23% of the cases. Even after surgery, recurrence rates of malignant struma ovarii can be as high as 35%. [1] Adjuvant thyroid targeting therapies such as radioiodine ablation after total thyroidectomy and TSH suppression therapy have been shown to reduce the risk of tumor recurrence similar to that of primary thyroid cancer.

Case Description

A 46-year-old healthy lady presented with a 3-month history of non-specific lower abdominal pain and inter-menstrual bleeding. An extensive review of systems was otherwise unremarkable. Ultrasound of the pelvis showed a 4 cm left adnexal mass. An MRI of the pelvis revealed a 2.2×3.6×2.4 cm solid, enhancing mass within the left ovary with an adjacent cystic component. Tumor markers including CEA, CA 19-9, and CA 125 were unremarkable. Due to suspicion for malignancy, she underwent laparoscopic left salpingo-oophorectomy and resection of the mass. Histopathology revealed papillary thyroid carcinoma approximately 1 cm in size with a background of struma ovarii. Immunohistochemistry staining showed positivity for thyroglobulin and Thyroid Transcription Factor-1 (TTF-1). BRAF mutation analysis was negative. An ultrasound of the thyroid gland disclosed two low-risk nodules. TSH was 1.070 mcIU/ml (0.450-4.500), and thyroglobulin level was 6.8ng/ml (1.5-38.5). We performed an Iodine-123 whole-body scan which was negative for abnormal radioiodine uptake. Based on these results, we classified this patients’ recurrence risk as low to intermediate. We initiated TSH suppression therapy with thyroid hormone to maintain TSH in the low normal range. We deferred total thyroidectomy and radioiodine ablation given the low recurrence risk. She will be monitored for recurrence with TSH and thyroglobulin panel at 6 and 12 months in the first year and then annually for at least the next ten years.

Discussion

Given the rarity of malignant struma ovarii, there are no consensus guidelines for identifying patients with a high recurrence risk who would benefit from thyroid targeting therapy. While some authors recommend total thyroidectomy and radioiodine ablation for all patients, a recent review [2] recommended an algorithm based on imaging, laboratory, and pathologic characteristics of the tumor to risk-stratify patients and treat them depending on their recurrence risk. Improved strategies for risk-stratification and follow-up are essential to provide optimal treatment for malignant struma ovarii patients without over-treating them.

References

1. Yassa L, Sadow P, Marqusee E et al. Malignant struma ovarii. Nat Clin Pract Endocrinol Metab 2008; 4: 469-472. 2. Addley S, Mihai R, Alazzam M et al. Arch Gynecol Obstet 2021; 303(4): 863-870

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

When Thirst Ceases to Exist: A Case Report and Literature Review of Adipsic Diabetes Insipidus Following Coil Embolization of a Ruptured Anterior Communicating Artery Aneurysm

Diabetes insipidus is a condition characterized by inappropriately dilute urine in the setting of serum hyperosmolality. The two predominant subtypes include central (from lack of vasopressin production) and nephrogenic diabetes insipidus (from renal resistance to circulating vasopressin). A common manifestation is the significant pursuant thirst from excessive polyuria. We present a case report and literature review of an infrequent variation of central diabetes insipidus known as adipsic (hypothalamic) diabetes insipidus, characterized by the absence of thirst, secondary to coiling of a ruptured anterior communicating artery aneurysm. Due to the loss of thirst, patients are at a heightened risk for hypernatremia and complications secondary to dehydration. Our patient's course was complicated by recurrent polyuria and hypernatremia, requiring a fixed-dose desmopressin regimen. On follow-up, only partial thirst sensation was restored. We provide a literature review to compare our case report to the scant literature available to broaden the awareness of this infrequent, perilous, manifestation.