Sugar prevalence in Aedes albopictus differs by habitat, sex and time of day on Masig Island, Torres Strait, Australia

Background

Sugar feeding is a fundamental behaviour of many mosquito species. For Aedes albopictus, an important vector of dengue virus and chikungunya virus, little is known about its sugar-feeding behaviour, and no studies have been conducted on this in the southern hemisphere. This knowledge is pivotal for determining the potential of attractive targeted sugar baits (ATSBs) to control this important vector.

Methods

The prevalence of sugar was assessed in 1808 Ae. albopictus from Masig Island, Torres Strait, Australia collected between 13 and 25 March 2020. Fructose presence and content in field-collected Ae. albopictus were quantified using the cold anthrone assay.

Results

Significantly more male (35.8%) than female (28.4%) Ae. albopictus were sugar fed. There was a significant interaction between sex and time of day on the probability of capturing sugar-fed Ae. albopictus. For both sexes, fructose prevalence and content were higher in mosquitoes caught in the morning than in the afternoon. Female Ae. albopictus collected in the residential habitat were significantly more likely to be sugar fed than those collected in the woodland habitat.

Conclusions

These findings provide baseline information about the sugar-feeding patterns of Ae. albopictus and provide essential information to enable an assessment of the potential of ATSBs for vector suppression and control on Masig Island, with relevance to other locations where this species occurs.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05020-w.

Neonatal Hypoglycemia: Is There a Sweet Spot?

Hypoglycemia is one of the most common neonatal problems. Despite increasing evidence that hypoglycemia is linked to neurologic impairment, knowledge regarding the specific value or duration of hypoglycemia that results in injury to the brain remains unclear. Current published statements/guidelines focused on preventing clinically significant hypoglycemia are conflicting and continue to be based on low evidence. This article reviews transitional events leading to extrauterine euglycemia, risk factors contributing to transient or persistent hypoglycemia, and common treatment approaches. Current information related to neurodevelopmental outcomes and screening strategies to prevent significant hypoglycemia with early treatment is described.

Perinatal outcome associated with outpatient management of triplet pregnancy

OBJECTIVE

Our goal was to compare the lengths of hospitalization and the perinatal outcomes of triplet pregnancies managed with either outpatient or inpatient third-trimester bed rest.

STUDY DESIGN

Thirty-two triplet pregnancies in which outpatient bed rest was prescribed (April 1993 to April 1996) were compared with a historic cohort of 34 triplets (January 1985 to March 1993) in which routine hospitalization was undertaken in the third trimester. Length of hospitalization and maternal and neonatal outcome parameters were compared between groups.

RESULTS

Maternal inpatient hospital days were significantly reduced for the group managed as outpatients, but combined maternal and neonatal hospitalization was similar between groups. The mean gestational age at delivery was 1 week greater in the hospitalized cohort (33.5+/-2.8 vs 32.5+/-2.8, respectively; p=0.16), and average birth weight was correspondingly greater in hospitalized cases (1942 gm vs 1718 gm, p < 0.005). Neonatal lengths of stay were similar between groups, reflecting earlier postnatal discharge in the outpatient era of this study. Preeclampsia occurred with greater frequency in the outpatient group (31.3% vs 8.8%, p=0.02), and the neonatal complication of intraventricular hemorrhage occurred more commonly in this cohort as well (10/96 vs 1/102, p=0.004). All other maternal and neonatal complications were similar between groups.

CONCLUSION

Reduction in the length of hospitalization attributable to outpatient management was limited to the maternal length of stay. It is possible that the observed maternal and neonatal complications in the outpatient group may have been related to less rigorous bed rest. We would suggest that the differences noted in preeclampsia, birth weight, and intraventricular hemorrhage support prospective evaluation of bed rest in triplet pregnancy.

Midtrimester amniocentesis. Influence of operator caseload on sampling efficiency

OBJECTIVE

To evaluate the impact of operator caseload on the sampling efficiency for early and standard, midtrimester amniocentesis.

STUDY DESIGN

Prospective ascertainment of genetic amniocenteses performed during 36 months, grouped into early (13-14 weeks' gestation) and standard procedures (15-20 weeks' gestation). Details of each amniocentesis were recorded immediately after sampling, and pregnancy outcomes were retrieved via questionnaires completed by the delivering physician. Sampling efficiency was evaluated separately in the early and standard cohorts in relation to operator caseload.

RESULTS

In total, 193 and 707 patients underwent early and standard amniocentesis, respectively. Forty of 46 physician-operators performed < 50 total procedures during the study interval (group A). When compared to operators performing > or = 50 cases (group B, n = 6), a higher rate of single-pass success was noted among group B physicians for both early and standard procedures (A vs. B, early: 40/45 vs. 145/148, P = .018; standard: 243/295 vs. 384/412, P < .0001). Logistic regression confirmed an independent effect of physician caseload on sampling efficiency and a significant interaction between physician caseload and simultaneous ultrasound guidance in predicting single-attempt success.

CONCLUSION

Operator caseload directly influenced sampling efficiency for both early and standard, midtrimester amniocentesis.

Molecular epidemiology study of a suspected community cluster of childhood cancers

We investigated the report of a community cluster of cancers in 33 children, which included two siblings known to have dominantly inherited Li-Fraumeni syndrome and a germline p53 mutation. After defining criteria for inclusion in the cluster, the 12 eligible childhood cancer probands diagnosed between 1980 and 1989 were not excessive (expected, ten cases). The corresponding childhood cancer mortality rates for the community fluctuated between 1950 and 1989 and were not increased overall. However, three additional probands had family histories of childhood cancer that suggested a forme fruste of Li-Fraumeni syndrome. The epidemiological data suggested a geographic cluster of this rare hereditary disorder, but absence of germline p53 mutation in the three other multicase families indicates genetic heterogeneity. Laboratory studies can assist analyses of suspected clusters, although investigations of geographic clusters of hereditary cancers raise complex issues of confidentiality and protection of affected individuals, their families, and the community.

Multifetal reduction increases the risk of preterm delivery and fetal growth restriction in twins: a case-control study

OBJECTIVE

To compare pregnancy outcome in twin gestations resulting from multifetal reduction to "primary" twin pregnancies derived from either spontaneous conception or infertility therapy.

DESIGN

Case-control study.

SETTING

University-affiliated tertiary center.

PATIENT(S)

Multifetal pregnancies (quadruplets or more) reduced to twins (group A) compared with twin gestations conceived either spontaneously (group B) or through infertility therapy (group C).

INTERVENTION(S)

Multifetal reduction for group A; perinatal care for groups A, B, and C.

MAIN OUTCOME MEASURE(S)

Comparison of perinatal complications between groups including antepartum bleeding, premature membrane rupture, and preterm labor. Neonatal outcomes compared including gestational age at delivery, birth weight, incidence of fetal growth restriction, and twin discordancy.

RESULT(S)

A higher incidence of idiopathic preterm labor was noted in group A cases (14/18) compared with either of the control groups (B: 26/54, or C: 24/54). As a consequence, group A had the lowest gestational age at delivery (32.6 +/- 3.9 weeks) compared with groups B (33.6 +/- 4.4 weeks) and C (36.0 +/- 3.4 weeks). Corresponding birth weights of both first- and second-born twins were significantly lower in group A compared with group C, whereas the birth weight comparison between groups A and B showed a nonsignificant difference. The proportion of pregnancies in which one or both twins weighted less than the 10th percentile was greatest in group A pregnancies (A: 5/18 versus C: 5/54). Discordant birth weight among twin pairs was proportionately greater for group A cases at both the 20% and 30% discordance levels.

CONCLUSION(S)

Twin gestations resulting from multifetal reduction are at increased risk for preterm birth, fetal growth restriction, and discordancy when compared with fertility therapy-derived, nonreduced twins.

Evaluation of nitric oxide as a mediator of severe preeclampsia

OBJECTIVE

Our purpose was to determine whether a reduction in nitric oxide synthesis occurs in women with severe preeclampsia as a consequence of soluble serum factors.

STUDY DESIGN

Circulating nitrate and nitrite levels were compared between women who met standard clinical criteria for severe preeclampsia (n = 21) and maternal or gestational age-matched, normotensive, primagravid control subjects (n = 21). End-products of nitric oxide synthesis were measured from venous blood samples using nitrate reduction and chemiluminescence. To detect in vitro suppression of nitric oxide synthesis, human umbilical vein endothelial cell monolayers were grown to confluence and exposed to culture media containing 20% severe preeclamptic or control sera. Nitrate and nitrite production were compared in duplicate monolayers for each experimental condition, expressed as means +/- SEM in picomoles per 10(6) cells. Data were compared by Student's t or Mann-Whitney U tests, when appropriate, along with Spearman correlations for comparisons of laboratory and clinical data.

RESULTS

Circulating nitrate and nitrite levels were similar in normotensive and preeclamptic cohorts (976 +/- 88 vs 1009 +/- 41 pmol/ml, respectively; p = 0.22), and no correlations between blood pressure and nitric oxide metabolite levels were observed for the control or severely preeclamptic subsets. Similar patterns of in vitro endothelial nitrite production were observed after 1-, 12-, and 24-hour incubations with 20% control or preeclamptic sera.

CONCLUSIONS

Circulating nitrate and nitrite levels are not reduced in patients with severe preeclampsia compared with normotensive controls, and sera from these women do not suppress endothelial cell nitric oxide synthesis in vitro.

Regulation of sterol 27-hydroxylase and an alternative pathway of bile acid biosynthesis in primary cultures of rat hepatocytes

In man, hepatic mitochondrial sterol 27-hydroxylase and microsomal cholesterol 7alpha-hydroxylase initiate distinct pathways of bile acid biosynthesis from cholesterol, the "acidic" and "neutral" pathways, respectively. A similar acidic pathway in the rat has been hypothesized, but its quantitative importance and ability to be regulated at the level of sterol 27-hydroxylase are uncertain. In this study, we explored the molecular regulation of sterol 27-hydroxylase and the acidic pathway of bile acid biosynthesis in primary cultures of adult rat hepatocytes. mRNA and protein turnover rates were approximately 10-fold slower for sterol 27-hydroxylase than for cholesterol 7alpha-hydroxylase. Sterol 27-hydroxylase mRNA was not spontaneously expressed in culture. The sole requirement for preserving sterol 27-hydroxylase mRNA at the level of freshly isolated hepatocytes (0 h) after 72 h was the addition of dexamethasone (0.1 microM; > 7-fold induction). Sterol 27-hydroxylase mRNA, mass and specific activity were not affected by thyroxine (1.0 microM), dibutyryl-cAMP (5O microM), nor squalestatin 1 (15O nM-1.0 microM), an inhibitor of cholesterol biosynthesis. Taurocholate (50 microM), however, repressed sterol 27-hydroxylase mRNA levels by 55%. Sterol 27-hydroxylase specific activity in isolated mitochondria was increased > 10-fold by the addition of 2-hydroxypropyl-beta-cyclodextrin. Under culture conditions designed to maximally repress cholesterol 7alpha-hydroxylase and bile acid synthesis from the neutral pathway but maintain sterol 27-hydroxylase mRNA and activity near 0 h levels, bile acid synthesis from [14C]cholesterol remained relatively high and consisted of beta-muricholate, the product of chenodeoxycholate in the rat. We conclude that rat liver harbors a quantitatively important alternative pathway of bile acid biosynthesis and that its initiating enzyme, sterol 27-hydroxylase, may be slowly regulated by glucocorticoids and bile acids.

Serum from patients with severe preeclampsia is not cytotoxic to endothelial cells

OBJECTIVE

We evaluated the hypothesis that circulating factors in preeclampsia promote direct endothelial cell injury using an in vitro index of cytotoxicity.

METHODS

Subconfluent umbilical vein endothelial cell monolayers were established and radiolabeled with chromium (51Cr), then randomly exposed for 24 hours in triplicate to 20% sera from nonlaboring patients with severe preeclampsia (n = 5) or mild preeclampsia and normotensive controls (n = 5). Additional experiments were performed by exposing endothelial monolayers to sera for 3 and 48 hours, and under hypoxic conditions (1% oxygen). Cytotoxicity was defined by the percentage of 51Cr release, expressed as the ratio of radioactivity in the supernatant to the maximum cell-associated radioactivity.

RESULTS

Mean 51Cr release was similar in all experiments comparing preeclamptic and normal sera. Although consistently greater 51Cr release was noted in hypoxic as compared with normoxic incubations, no differences in cytotoxicity were identified among severe preeclampsia, mild preeclampsia, and normal sera in hypoxia.

CONCLUSION

Sera from patients with preeclampsia do not appear to be cytotoxic to vascular endothelium in this in vitro model.

pH-related changes in the absorption of dipyridamole in the elderly

The bioavailability of dipyridamole, a poorly soluble weak base, was evaluated in 11 healthy, older subjects (> or = 65 years), 6 with a low fasting gastric pH (control) and 5 with a fasting gastric pH > 5 (achlorhydric), in a randomized, crossover design. Subjects received 50 mg dipyridamole as a single oral dose both with and without pretreatment with 40 mg famotidine (control subjects) or 1360 mg glutamic acid HCl (achlorhydric subjects). Gastric pH was monitored by Heidelberg radiotelemetric capsule. Gastric emptying of 99mTc-radiolabeled orange juice was measured. Gastric pH appeared to be a primary determinant in dipyridamole absorption in the elderly. Elevated gastric pH resulted in compromised dipyridamole absorption compared to low-gastric pH conditions in all cases. The administration of glutamic acid hydrochloride to achlorhydric subjects prior to the dose of dipyridamole corrected for the decreased Cmax and AUC(0-36) exhibited in achlorhydric subjects without pretreatment. Tmax and ka were slower in achlorhydrics, although pretreatment with glutamic acid HCl tended to normalize these parameters. Based on these results, it would be beneficial for achlorhydrics to take glutamic acid hydrochloride prior to taking dipyridamole and other medications which need a low gastric pH for complete absorption. The administration of 40 mg famotidine was successful in elevating the gastric pH to > 5 in all subjects and maintained it at > 5 for at least 3 hr in all subjects tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Upper gastrointestinal pH in seventy-nine healthy, elderly, North American men and women

Gastric and duodenal pH levels were measured in 79 healthy, elderly men and women (mean +/- SD = 71 +/- 5 years) under both fasted and fed conditions using the Heidelberg capsule technique. The pH was recorded for 1 hr in the fasted state, a standard liquid and solid meal of 1000 cal was given over 30 min, then the pH was measured for 4 hr postprandially. Results are given as medians and interquartile ranges: fasted gastric pH, 1.3 (1.1-1.6); gastric pH during the meal, 4.9 (3.9-5.5); fasted duodenal pH, 6.5 (6.2-6.7); and duodenal pH during the meal, 6.5 (6.4-6.7). Although fasted gastric pH, fasted duodenal pH, and duodenal pH during the meal differ statistically from those observed in young subjects, the differences are not expected to be clinically significant in terms of drug absorption for the majority of elderly subjects. Following a meal, gastric pH decreased from a peak pH of 6.2 (5.8-6.7) to pH 2.0 within 4 hr in most subjects. This rate of return was considerably slower than in young, healthy subjects. Nine subjects (11%) had a median fasted gastric pH > 5.0, and in five of these subjects the median pH remained > 5.0 postprandially. In this group, drugs and dosage forms which require an acidic environment for dissolution or release may be poorly assimilated.

Upper gastrointestinal (GI) pH in young, healthy men and women

The pH in the upper gastrointestinal tract of young, healthy men and women was measured in the fasting state and after administration of a standard solid and liquid meal. Calibrated Heidelberg capsules were used to record the pH continuously over the study period of approximately 6 hr. In the fasted state, the median gastric pH was 1.7 and the median duodenal pH was 6.1. When the meal was administered the gastric pH climbed briefly to a median peak value of 6.7, then declined gradually back to the fasted state value over a period of less than 2 hr. In contrast to the pH behavior in the stomach, feeding a meal caused a reduction in the median duodenal pH to 5.4. In addition, there was considerable fluctuation in the postprandial duodenal pH on an intrasubject basis. The pH in the duodenum did not return to fasted state values within the 4-hr postprandial observation period. There was no tendency for the duodenal pH to be related to the gastric pH in either the fed or fasted phases of the study. Furthermore, pH in the upper GI tract of young, healthy subjects appears to be independent of gender. The differences in upper GI pH between the fasted and the fed state are discussed in terms of dosage form performance and absorption for orally administered drugs.

Upper gastrointestinal (GI) pH in young, healthy men and women

The pH in the upper gastrointestinal tract of young, healthy men and women was measured in the fasting state and after administration of a standard solid and liquid meal. Calibrated Heidelberg capsules were used to record the pH continuously over the study period of approximately 6 hr. In the fasted state, the median gastric pH was 1.7 and the median duodenal pH was 6.1. When the meal was administered the gastric pH climbed briefly to a median peak value of 6.7, then declined gradually back to the fasted state value over a period of less than 2 hr. In contrast to the pH behavior in the stomach, feeding a meal caused a reduction in the median duodenal pH to 5.4. In addition, there was considerable fluctuation in the postprandial duodenal pH on an intrasubject basis. The pH in the duodenum did not return to fasted state values within the 4-hr postprandial observation period. There was no tendency for the duodenal pH to be related to the gastric pH in either the fed or fasted phases of the study. Furthermore, pH in the upper GI tract of young, healthy subjects appears to be independent of gender. The differences in upper GI pH between the fasted and the fed state are discussed in terms of dosage form performance and absorption for orally administered drugs.

Identification and isolation of an axonal plasma membrane enriched fraction from cerebellar granule cell neurites

A procedure is described to isolate a fraction enriched in cerebellar granule cell neuritic membranes. Morphological markers that are specific for either the granule cell perikarya or neuritic membranes have been identified. Concanavalin A (Con A) has been shown to bind predominantly to the granule cell neurites whereas, the enzymes acetylcholinesterase (AChE) and 2',3',cyclic nucleotide-3'-phosphohydrolase (CNPase) are localized predominantly in the neuronal cell bodies. The membrane fraction enriched in Con A binding has been used to generate a monoclonal antibody which morphologically recognized the cerebellar granule cell neuritic membrane. Following fractionation of the granule cells, each marker was used to identify the cellular origin of the fractions. The neuritic markers Con A and the neuritic membrane antibody MR2 bound predominantly to membranes found in the 29.1% and 31.5% region of the sucrose gradient. The perikaryal markers, CNPase and AChE activity were most enriched in membrane fractions found at a sucrose concentration of 23% and 21%, respectively. Morphological examination of the neuritic enriched fraction shows that it contains predominantly membranous material with few subcellular organelles. The protein profiles of the cerebellar granule cell fractions are unique when compared with the protein profiles of other neuronal and non-neuronal fractions. The membrane fraction isolated from the cerebellar granule cells should prove useful in furthering our understanding of the axonal influence on glial development.