Women and ARVâ based prevention: opportunities and challenges

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138349/1/jia29419.pd

Reduced Hamster Usage and Stress in Propagating \u3ci\u3eLeishmania chagasi\u3c/i\u3e Promastigotes Using Cryopreservation and Saphenous Vein Inoculation

Leishmania chagasi, a causal agent of visceral leishmaniasis, requires passage through lab animals such as hamsters to maintain its virulence. Hamster infection is typically accomplished via cardiac puncture or intraperitoneal injection, procedures accompanied by risks of increased animal stress and death. The use of the hamster model also necessitates a regular supply of infected animals, because L. chagasi parasites newly isolated from an infected hamster can be grown in culture for only several weeks before loss of function/phenotype occurs. In an effort to decrease animal usage and animal stress, experiments were performed to assess a more gentle inoculation procedure (saphenous vein inoculation) and the use of cryopreserved parasite cells for research experiments. Of 81 hamsters inoculated by the saphenous vein, 80 became infected as determined ante mortem, by display of clinical symptoms of leishmaniasis (onset of symptoms at 105 ± 22 days post-inoculation), and postmortem by the presence of parasites within the spleen. Splenic parasite load calculated for a subset (n 5 34) of infected hamsters was 124 to 26,177 Leishmania donovani infection units. Cryopreserved, and never-stored, cells were equivalent in all properties evaluated, including developmental changes in morphology during culture, culture growth rates, parasite resistance to serum-mediated lysis, and expression of developmentally regulated surface proteins major surface protease and promastigote surface antigen

Glucose metabolism in 105 children and adolescents after pancreatectomy for congenital hyperinsulinism

OBJECTIVE - To describe the long-term metabolic outcome of children with congenital hyperinsulinism after near-total or partial elective pancreatectomy. RESEARCH DESIGN AND METHODS - Patients (n = 105: 58 diffuse and 47 focal congenital hyperinsulinism) received operations between 1984 and 2006. Follow-up consisted of periodic measurements of pre- and postprandial plasma glucose over 24 h,OGTT, and IVGTT. Cumulative incidence of hypo- or hyperglycemia/insulin treatment was estimated by Kaplan- Meier analysis. RESULTS - After near-total pancreatectomy, 59% of children with diffuse congenital hyperinsulinism still presented mild or asymptomatic hypoglycemia that responded to medical treatments and disappeared within 5 years. One-third of the patients had both preprandial hypoglycemia and postprandial hyperglycemia. Hyperglycemia was found in 53% of the patients immediately after surgery; its incidence increased regularly to 100% at 13 years. The cumulative incidence of insulin-treated patients was 42% at 8 years and reached 91% at 14 years, but the progression to insulin dependence was very variable among the patients. Plasma insulin responses to IVGTT and OGTT correlated well with glycemic alterations. In focal congenital hyperinsulinism, hypoglycemia or hyperglycemia were rare, mild, and transient. CONCLUSIONS - Patients with focal congenital hyperinsulinism are cured of hypoglycemia after limited surgery, while the outcome of diffuse congenital hyperinsulinism is very variable after near-total pancreatectomy. The incidence of insulin-dependent diabetes is very high in early adolescence. © 2012 by the American Diabetes Association

Congenital hyperinsulinism: pancreatic [18F]fluoro-L-dihydroxyphenylalanine (DOPA) positron emission tomography and immunohistochemistry study of DOPA decarboxylase and insulin secretion.

CONTEXT: Congenital hyperinsulinism (HI) is characterized by hypoglycemia related to inappropriate insulin secretion. Focal and diffuse forms of hyperinsulinism share a similar clinical presentation, but their treatment is dramatically different. Preoperative differential diagnosis was based on pancreatic venous sampling, a technically demanding technique. OBJECTIVE: Positron emission tomography (PET) after injection of [18F]fluoro-L-DOPA (L-dihydroxyphenylalanine) has been evaluated for the preoperative differentiation between focal and diffuse HI, by imaging uptake of radiotracer and the conversion of [18F]fluoro-L-dopa into dopamine by DOPA decarboxylase. We propose to validate this test by immunohistochemical approach. PATIENTS AND METHODS: Pancreatic surgical specimens of four focal and three diffuse HI were studied, using anti-DOPA decarboxylase and proinsulin antibodies. The effect of an inhibitor of DOPA decarboxylase (carbidopa) on insulin secretion was evaluated in vivo and in cultured INS-1 cells. RESULTS: Immunohistochemical detection of DOPA decarboxylase showed diffuse staining of Langerhans islets in the whole pancreas in all diffuse cases, in contrast with dense focal staining in all focal cases. Staining of Langerhans islets outside the focal lesion was diffusely but weakly positive. We correlated the localization of DOPA decarboxylase and proinsulin in normal pancreas and in both diffuse and focal HI tissues. The diffuse PET uptake found before treatment in one child with diffuse HI disappeared completely after carbidopa administration, suggesting in vivo that pancreatic cells can take up amine precursors and contain DOPA decarboxylase. The insulin secretion measured in the supernatant was the same whether INS-1 cells were treated by dopamine or Lodosyn or untreated. CONCLUSION: We validate PET with as a consistent test to differentiate diffuse and focal HI

Acute insulin responses to calcium and tolbutamide do not differentiate focal from diffuse congenital hyperinsulinism.

Congenital hyperinsulinism (CHI) is related to two main histological pancreas anomalies: focal adenomatous hyperplasia and diffuse beta-cell hypersecretion. Pharmacological tests to measure acute insulin responses (AIR) to peripheral i.v. injections of glucose, calcium, and tolbutamide have been reported as potential means to distinguish between these histological forms. In patients with defects in ATP-sensitive potassium channels, tolbutamide will fail to induce insulin release in affected portions of the pancreas, whereas calcium gluconate will enhance insulin release through spontaneously active voltage-gated Ca(2+) channels. Consequently, in focal CHI patients, calcium should promote AIRs from the lesion, whereas tolbutamide should act to promote insulin secretion from the healthy region of the pancreas (outside the focal hyperplasia). We therefore studied AIRs to calcium and tolbutamide stimulation tests in 16 children with focal (n = 9) or diffuse (n = 7) CHI before pancreatic surgery. We found hypervariable AIRs to glucose and calcium stimulation in both focal and diffuse CHI patients. AIRs to tolbutamide stimulation were found modest in focal CHI patients, which might account for beta-cell quiescence in the healthy portion of the pancreas of these patients. We conclude that AIRs to calcium and tolbutamide stimulation tests are not sufficient to differentiate the focal from the diffuse CHI patients