Sexual Pleasure and Healthcare Settings: Focusing on Pleasure to Improve Healthcare Delivery and Utilization

Sexual pleasure is best attained through facilitating access to the highest standard of health. Today global data show a persistent high burden of sexual health issues. Yet, pleasure remains a sensitive, stigmatized, and unspoken topic in healthcare services. This article examines how to incorporate a value for pleasure into healthcare services, grounded in the assumption that pleasure is a fundamental reason why people have sex and that acknowledging this can support people in creating safer, more pleasurable sexual experiences. Drawing upon examples from the literature and field experience, this article explores how to better address pleasure in healthcare settings.

Modelling the global impact of the 13-valent pneumococcal vaccine on antibiotic use for otitis media

Background

Antimicrobial resistance (AMR) is a critical issue in global health causing approximately 1 million annual deaths. Vaccines are essential in addressing AMR as they reduce resistant strains and prevent development of resistance by preventing spread of disease and resulting antimicrobial use. This analysis evaluates the impact the 13-valent pneumococcal conjugate vaccine (PCV13) has had on dispensed antibiotic prescriptions (DAP) due to otitis media (OM), one of the largest drivers of DAP globally.

Methods

An Excel-based model was developed to estimate number of infants vaccinated with PCV13, and the associated reduction in OM cases in children <5 since 2010. OM cases averted were based on a global meta-analysis and estimated cases averted were applied to infants vaccinated by country. DAP avoided were estimated assuming 90% of OM cases were prescribed an antibiotic. We then compared our modelled estimates to metrics measuring number needed to vaccinate to prevent DAP from any outcome.

Results

Over the past 10 years, we estimated 286,54m infants were vaccinated with PCV13, with 158,33m OM cases and as many as 142,49m DAP avoided globally. By WHO region, reductions in OM rates and DAP respectively are estimated to have been; Africa and Eastern Mediterranean (103,05m; 92,74m), South-East Asia and Western Pacific (8,82m; 7,94m), Europe (20,70m; 18,63m) and Americas (25,76m; 23,18m). Using rates from the literature of 0,20 to 1,79 total DAP avoided per child vaccinated, results ranged from to 71,63m to 511,68m.

Conclusions

PCV13 use has resulted in substantial reductions in OM and DAP. As we focus on OM in children <5, results underestimate the full impact of PCV13 on DAP as vaccine impact on other pneumococcal diseases and adults through herd effect are not included. Recognition of the role of vaccination in addressing AMR burden is an opportunity to encourage patients, providers and healthcare systems to continually prioritize vaccination in public health efforts.

Key messages

Over the past 10 years, PCV13 has led to considerable reductions in dispensed antibiotic prescriptions globally, highlighting the importance of prioritizing vaccination in global healthcare systems. Our findings illustrate how vaccines can play an essential role in reducing the global burden of antimicrobial resistance through reduction of antibiotic use.

Editorial: Diagnostic Testing for SARS-Coronavirus-2 in the Nursing Facility: Recommendations of a Delphi Panel of Long-Term Care Clinicians

With the COVID-19 pandemic progressing, guidance on strategies to mitigate its devastating effects in nursing facilities (NFs) is critical to preventing additional tragic outcomes. Asymptomatic spread of COVID-19 from nursing facility staff and residents is a major accelerator of infection. Facility-wide point-prevalence testing is an emerging strategy in disease mitigation. Because time is not available to await the results of randomized controlled trials before implementing strategies in this high-risk setting, an expert Delphi panel composed of experienced long-term care medicine professionals has now met to provide testing guidance for SARS-Coronavirus-2 to NFs. After many email and telephone discussions, the panel responded to a questionnaire that included six different scenarios, based on varying availability of Polymerase Chain Reaction (RT-PCR) testing and personal protective equipment (PPE). The panel endorsed facility-wide testing of staff and residents without dissent when diagnostic RT-PCR was available. While the panel recognized the limitations of RT-PCR testing, it strongly recommended this testing for both staff and residents in NFs that were either COVID-19 naive or had limited outbreaks. There was also consensus on testing residents with atypical symptoms in a scenario of limited testing capability. The panel favored testing every 1 to 2 weeks if testing was readily available, reducing the frequency to every month as community prevalence declined or as the collection of additional data further informed clinical critical thinking and decision-making. The panel recognized that frequent testing would have consequences in terms of potential staff shortages due to quarantine after positive tests and increased PPE use. However, the panel felt that not testing would allow new clusters of infection to form. The resulting high mortality rate would outweigh the potential negative consequences of testing. The panel also recognized the pandemic as a rapidly evolving crisis, and that new science and increasing experience might require an updating of its recommendations. The panel hopes that its recommendations will be of value to the long-term care industry and to policy makers as we work together to manage through this challenging and stressful time.

Trends in vaccine investment in middle income countries

Although a proven and effective preventive health measure, childhood immunization programs remain vulnerable to budgetary pressures. Sustainable financing of immunization programs is an important issue that presents a challenge for middle-income countries (MIC) in particular, in part due to technological advances meaning more vaccines are available. This study aimed to analyse trends in immunization program investment across 15 MIC selected based on availability of data, income level classification, and regional representativeness. We assessed investment trends in relation to vaccine coverage, vaccine access, and broader health indicators. Immunization and expenditure data were obtained from the World Health Organisation (WHO) database and the WHO UNICEF Joint Reporting Form and WHO Vaccine Product, Price and Procurement from 2006-2016. We calculated a weighted average index of vaccine commitment (WAIVC) based on vaccine coverage, vaccine scope, and weighted by vaccine innovation measured by approximating vaccine expenditure. Correlation analyses were conducted between immunization expenditure per-capita and each WAIVC, infant mortality and life expectancy. Correlation analyses at a global and individual country level indicate an improvement in immunization access, vaccination commitment measured by WAIVC, and scope of available vaccines in countries with sustained increases in vaccination funding. Increases in national immunization expenditure were correlated with reduced infant mortality and increased life expectancy. Vaccine expenditure comprises a small proportion (less than 2%) of total healthcare spending and has not uniformly increased in accordance with the scope of available vaccines. The present analysis supports the premise that countries with consistent increases in vaccine expenditure have increased vaccine coverage and commitment measured by WAIVC and improved broader health outcomes, indicating the value of sustained investment in vaccination for improved population health. The benefits of vaccine expenditure in this holistic fashion are critical to inform policy decisions on national budget allocation for vaccine funding.

Do Drains Contribute to Pancreatic Fistulae? Analysis of over 5000 Pancreatectomy Patients

INTRODUCTION

Conflicting evidence exists from randomized controlled trials supporting both increased complications/fistulae and improved outcomes with drain placement after pancreatectomy. The objective was to determine drain practice patterns in the USA, and to identify if drain placement was associated with fistula formation.

METHODS

Demographic, perioperative, and patient outcome data were captured from the most recent annual NSQIP pancreatic demonstration project database, including components of the fistula risk score. Significant variables in univariate analysis were entered into adjusted logistic regression models.

RESULTS

Of 5013 pancreatectomy patients, 4343 (87%) underwent drain placement and 18% of patients experienced a pancreatic fistula. When controlled for other factors, drain placement was associated with ducts < 3 mm, soft glands, and blood transfusion within 72 h of surgery. Age, obesity, neoadjuvant radiation, preoperative INR level, and malignant histology lost significance in the adjusted model. Drained patients experienced higher readmission rates (17 vs. 14%; p < 0.05) and increased (20 vs. 8%; p < 0.01) pancreatic fistulae. Fistula was associated with obesity, no neoadjuvant chemotherapy, drain placement, < 3 mm duct diameter, soft gland, and longer operative times. Drain placement remained independently associated with fistula after both distal pancreatectomy (OR = 2.84 (1.70, 4.75); p < 0.01) and pancreatoduodenectomy (OR = 2.29 (1.28, 4.11); p < 0.01).

CONCLUSIONS

Despite randomized controlled clinical trial data supporting no drain placement, drains are currently placed in the vast majority (87%) of pancreatectomy patients from > 100 institutions in the USA, particularly those with soft glands, small ducts, and perioperative blood transfusions. When these factors are controlled for, drain placement remains independently associated with fistulae after both distal and proximal pancreatectomy.

The natural history of anal transition zone inflammation and possible relationship to pouchitis: a long-term longitudinal study

AIM

Reservoir ileitis (pouchitis) is the most common complication after pelvic pouch surgery for ulcerative colitis and the aetiology remains largely unknown. The anal transition zone (ATZ) contains the only remaining colonic epithelium after ileal pouch anal anastomosis (IPAA) and may provide important clues as to whether ulcerative colitis and pouchitis share a common pathogenesis. The aim of this study was to evaluate longitudinally the long-term histological changes in the ATZ and their relationship to the incidence of pouchitis.

METHOD

Patients with a double-stapled IPAA for ulcerative colitis at an academic medical centre with at least 10 years of clinical and histological follow-up were identified from a prospective database. Annual ATZ and pouch biopsies were taken and interpreted by two expert gastrointestinal pathologists. ATZ histological variability score, the incidence of pouchitis, and function were correlated over time. ATZ biopsies were scored from one to three based on the extent of inflammation.

RESULTS

Sixteen of the 114 patients having IPAA fulfilled the criteria for admission to the study. There were 179 biopsies of the ATZ. All exhibited variability in ATZ histology over time and 81% had a 2-unit change in their inflammatory score. There was no correlation between pouchitis and histological severity score of the ATZ. Similarly, function over time did not vary with the intensity of ATZ inflammation.

CONCLUSION

ATZ inflammation varies substantially over time in most patients. But these changes from year to year did not correlate with function or the occurrence of pouchitis.

Summary of the recommendations on sexual dysfunctions in men

INTRODUCTION

Sexual health is an integral part of overall health. Sexual dysfunction can have a major impact on quality of life and psychosocial and emotional well-being.

AIM

To provide evidence-based, expert-opinion consensus guidelines for clinical management of sexual dysfunction in men.

METHODS

An international consultation collaborating with major urologic and sexual medicine societies convened in Paris, July 2009. More than 190 multidisciplinary experts from 33 countries were assembled into 25 consultation committees. Committee members established scope and objectives for each chapter. Following an exhaustive review of available data and publications, committees developed evidence-based guidelines in each area. Main Outcome Measures.  New algorithms and guidelines for assessment and treatment of sexual dysfunctions were developed based on work of previous consultations and evidence from scientific literature published from 2003 to 2009. The Oxford system of evidence-based review was systematically applied. Expert opinion was based on systematic grading of medical literature, and cultural and ethical considerations.

RESULTS

Algorithms, recommendations, and guidelines for sexual dysfunction in men are presented. These guidelines were developed in an evidence-based, patient-centered, multidisciplinary manner. It was felt that all sexual dysfunctions should be evaluated and managed following a uniform strategy, thus the International Consultation of Sexual Medicine (ICSM-5) developed a stepwise diagnostic and treatment algorithm for sexual dysfunction. The main goal of ICSM-5 is to unmask the underlying etiology and/or indicate appropriate treatment options according to men's and women's individual needs (patient-centered medicine) using the best available data from population-based research (evidence-based medicine). Specific evaluation, treatment guidelines, and algorithms were developed for every sexual dysfunction in men, including erectile dysfunction; disorders of libido, orgasm, and ejaculation; Peyronie's disease; and priapism.

CONCLUSIONS

Sexual dysfunction in men represents a group of common medical conditions that need to be managed from a multidisciplinary perspective.

Health information Websites: characteristics of US users by race and ethnicity

We conducted a national public opinion survey of adults aged 18 years or older in the continental US to determine their use of health Websites. Of the 928 individuals contacted, 868 (94%) reported their race/ethnicity. More non-Hispanic Whites reported using the Internet (34%) than African Americans (31%) and Hispanics (20%). We used logistic regression to estimate adjusted odds ratios describing the relationship between Website usage and covariates across the racial/ethnic subgroups. Whereas better perceived health was associated with greater Website use among Hispanics and Whites, stronger health literacy was associated with greater use among Hispanics. No African American or Hispanic respondent aged 65 years or older reported going online. The relationship between education and use was more than twice as strong for African Americans and Hispanics than other groups. That some minority groups are less likely to use the World Wide Web for health information may further compound existing disparities. One place where this problem may be addressed is in the nation's schools.

Quick and efficient purification of Giardia intestinalis cysts from fecal samples

Giardia intestinalis is an intestinal parasite that has sparked considerable interest because of the public health problem it creates and because it is regarded as one of the earliest divergent eukaryotes. The present report describes a new method for quick, clean, and effective isolation of G. intestinalis cysts from fecal samples. The isolated cysts have the quality required for biochemical studies of the excystation process.

Chronic lithium treatment of B lymphoblasts from bipolar disorder patients reduces transient receptor potential channel 3 levels

Chronic lithium treatment of B-lymphoblast cell lines (BLCLs) from bipolar-I disorder (BD-I) patients and healthy subjects ex vivo attenuates agonist- and thapsigargin-stimulated intracellular calcium (Ca(2+)) responses. As these findings suggest that chronic lithium treatment modifies receptor (ROCE) and/or store-operated Ca(2+) entry (SOCE) mechanisms, we determined whether chronic lithium treatment of BLCLs modified the expression of two members of the transient receptor potential channels (TRPC1 & 3), which participate in ROCE/SOCE. Chronic lithium treatment significantly reduced BLCL TRPC3 immunoreactivity (repeated-measures ANOVA, P=0.00005), with interaction effects of diagnosis (P=0.037) and sex (P=0.040). The lithium-induced decrease was greatest in BLCLs from female BD-I patients compared with those from healthy females (-27%) and with vehicle-treated BLCLs from female BD-I patients (-33%). However, lithium treatment did not affect TRPC1 and 3 mRNA levels, and TRPC1 immunoreactivity. Downregulation of TRPC3 may be an important mechanism by which lithium ameliorates pathophysiological Ca(2+) disturbances as observed in BD.

Genetic divergence within the Drosophila mayaguana subcluster, a closely related triad of Caribbean species in the repleta species group

The mayaguana triad of the Drosophila repleta species group includes D. mayaguana, D. straubae, and D. parisiena, the latter two of which are very similar when examined morphologically. Many morphological characters used to define these taxa are quantitative and overlap substantially among some forms--it is only through suites of such characters that species can be identified. We apply Population Aggregation Analysis and tree building methods to five rapidly evolving gene regions--the mitochondrial AT rich region and the nuclear acetylcholinesterase, hunchback, mastermind, and vestigial loci to test the morphological species delineations within the morphocryptic mayaguana triad. We find that D. mayaguana is diagnosable using DNA sequences, but the other two species form a non-diagnosable paraphyletic assemblage. A single ecological factor, oviposition substrate, is an important diagnostic character distinguishing D. straubae from D. parisiena, highlighting the importance of examining a diverse array of data (morphological, molecular, ecological, and behavioral) when defining species limits.

Expression of housekeeping genes during the asexual cell cycle of Plasmodium falciparum

In an earlier study, we found that calmodulin displayed an atypical expression for a housekeeping gene during the erythrocytic cycle of Plasmodium falciparum. The expression pattern was that of an inducible gene linked to the cell cycle, with a peak prior to replication, and not one of a gene that expresses itself in a constitutive way. In this work, we examined the expression pattern of other housekeeping genes, selecting genes from two functionally very different groups: those for three enzymes involved in carbohydrate metabolism--glucose-phosphate-isomerase (GPI), aldolase and glucose-6-phosphate-dehydrogenase (G6PD)--and for three proteins with structural and motor functions--actin-I, beta-tubulin and myosin. The mRNA of each gene was measured by reverse transcription-polymerase chain reaction in synchronic parasite samples that were 14, 28, 40 and 48 h old. GPI and G6PD achieved their maximum expression at 28 h, then declined, while aldolase increased its expression up to 40 h and remained high, but less so at 48 h. Actin and myosin showed the same pattern, increasing up to 48 h, while beta-tubulin expression peaked at 40 h. These findings confirm unconventional behavior in the expression of certain Plasmodium housekeeping genes and suggest the existence of different expression patterns for distinct functional groups.

Plasmodium falciparum: underestimation of dihydrofolate reductase and dihydropteroate synthase polymorphism in field samples: a technical shortcoming of nested PCR assays with mutation-specific primers

n a study parallel to the present one, we conducted a genotype characterization of Plasmodium falciparum based on isolates of patients infected with malaria, who come from a small location in Colombia. The analysis involved extraction of DNA from hematological smears, amplification of the dihydrofolate reductase gene and the dihydropteroate synthase (DHPS) gene for each sample by PCR, and detection through mutation-specific primers nested PCR of mutations associated with resistance to pyrimethamine and sulfadoxine. Given the difficulty in quantifying the DNA extracts due to the type of sample and its heterogeneity, different volumes of the product of the first PCR were tested as template for the nested PCR. Surprisingly, for some samples, we found contradictory results between determinations, which differed only in the amount of template used. This prompted a more general concern that in a natural isolate, where the parasite population is heterogeneous, the nested PCR with mutation-specific primers technique can produce erroneous results that underestimate the complexity of the sample. To test this hypothesis, we designed experiments in this study using position 581 of the DHPS gene as an indicator system and constructed samples simulating the heterogeneity of natural samples. In effect, our data show that the results obtained in the nested PCR can be altered by the amount of template used in the reaction and, therefore, some heterogeneous samples might be classified mistakenly as homogeneous, simple mutant or simple wild type. These observations may explain, at least in part, contradictory results found in the literature. Our data also suggest the need for a more cautious approach to interpretation of the results of nested PCR assays with mutation-specific primers and their implications in the definition of resistance to the pyrimethamine-sulfadoxine combination.

Stereoselective pharmacokinetic analysis and antiepileptic activity of N-2-hydroxypropyl valpromide, a central nervous system--active chiral valproylamide

The purpose of this study was to evaluate the anticonvulsant activity and pharmacokinetics (PK) of a novel chiral CNS-active 2-hydroxypropyl valpromide (HP-VPD), a derivative of valproic acid (VPA). The individual enantiomers, R, S, and racemic (R,S)-HP-VPD were synthesized and evaluated for their pharmacokinetics and pharmacodynamics in a stereoselective manner. A stereoselective gas chromatography (GC) assay for simultaneous quantification of HP-VPD enantiomers in plasma and urine was developed and used to investigate the pharmacokinetics of HP-VPD in dogs. Pharmacodynamic analysis in rats showed that (S)-HP-VPD was 2.5 times more potent as an anticonvulsant in the maximal electroshock seizure (MES) test than its enantiomer and approximately 10 times more potent than VPA. No significant differences were observed in major PK parameters (clearance, volume of distribution, and half-life) between S and (R)-HP-VPD, and this suggested that pharmacodynamic differences could be attributed to the intrinsic pharmacodynamics of each enantiomer rather than to a preferable pharmacokinetic profile. The pharmacokinetic (metabolic) analysis showed that the fraction metabolized to HP-VPD-glucuronide ranged from 5% to 7% and no biotransformation of HP-VPD to VPA and 2-ketopropyl valpromide was observed. This is the first report of significant stereoselectivity in the anticonvulsant activity of a valproylamide with a chiral carbon situated on the alkyl chain of the amine moiety.

Cytochemical localisation of calcium ATPase activity during the erythrocytic cell cycle of Plasmodium falciparum

Using a cytochemical technique, we evaluated the levels of Ca(2+)-ATPase activity in the plasmatic and in the parasitophorous vacuole membrane through the different developmental stages of the Plasmodium falciparum parasitised erythrocyte. We found that the activity is detectable and remains unaltered in the plasma membrane throughout the 48 h cell cycle. However, in the parasitophorous membrane, although the activity was very similar to that measured in the plasma membrane of the young stages (younger than 20-h-old parasites), it diminished gradually with maturation and in schizonts it was almost undetectable. These data suggest that the plasma membrane Ca(2+)-ATPase is important in the maintenance of a low erythrocyte cytoplasmic Ca(2+) concentration, and that in addition it could be a way to supply the vital cation to the parasite at the beginning of the infection, when other transport mechanisms have not yet developed.

Phylogenetic analysis of the repleta species group of the genus Drosophila using multiple sources of characters

The species in the repleta group of the genus Drosophila have been placed into five subgroups-the mulleri, hydei, mercatorum, repleta, and fasciola subgroups. Each subgroup has been further subdivided into complexes and clusters. Extensive morphological and cytological analyses of the members of this species group have formed the foundation for the proposed relationships among the members of the repleta species group. Fifty-four taxa, including 46 taxa belonging to the repleta species group, were sequenced for fragments of four genes-16S ribosomal DNA (16S), cytochrome oxidase II (COII), and nitrogen dehydrogenase 1 (ND1) of the mitochondrial genome and a region of the hunchback (hb) nuclear gene. We also generated a partial data set of elongation factor 1-alpha (Ef1alpha) sequences for a subset of taxa. Our analysis used both DNA characters and chromosomal inversion data. The phylogenetic hypothesis we obtained supports many of the traditionally accepted clades within the mulleri subgroup, but the monophyly of taxonomic groups outside of this subgroup appears not to be supported. Phylogenetic analysis revealed one well-supported, highly resolved clade that consists of closely related members of the mulleri and buzzatii complexes. The remaining taxa, a wide assortment of taxonomic groups, ranging from members of other species groups to members of several subgroups and members of three species complexes from the mulleri subgroup are found in poorly supported arrangements at the base of the tree.

Isolation and identification of actin-binding proteins in Plasmodium falciparum by affinity chromatography

The invasion of the erythrocyte by Plasmodium falciparum depends on the ability of the merozoite to move through the membrane invagination. This ability is probably mediated by actin dependent motors. Using affinity columns with G-actin and F-actin we isolated actin binding proteins from the parasite. By immunoblotting and immunoprecipitation with specific antibodies we identified the presence of tropomyosin, myosin, a-actinin, and two different actins in the eluate corresponding to F-actin binding proteins. In addition to these, a 240-260 kDa doublet, different in size from the erythrocyte spectrin, reacted with an antibody against human spectrin. All the above mentioned proteins were metabolically radiolabeled when the parasite was cultured with 35S-methionine. The presence of these proteins in P. falciparum is indicative of a complex cytoskeleton and supports the proposed role for an actin-myosin motor during invasion.

Changes in bone mineral density after discontinuation and early reinstitution of growth hormone (GH) in patients with childhood-onset GH deficiency

We measured bone mass density (BMD) in 28 childhood-onset adult GHD patients (20 MPHD, 8 IGHD) treated with hGH until final height. Twelve were re-treated with hGH (0.06 U/kg/day three times per week) for 16-24 months and eight of them followed for up to 5 years. Age at start of the study was 23.6 +/- 5.7 years (mean +/- SD) and the interval since the first hGH treatment was 5.8 +/- 4.4 years Baseline BMD was 82% of young normal healthy subjects. Patients < 20 years had a lower BMD than those > 20 years (75 vs 87%;P = 0.004). In the 12 patients re-treated with GH, BMD was 5.3% above baseline at 6 months after treatment was stopped (P< 0.002), and remained so for 3.5 years in eight patients who completed follow-up. In conclusion, increases in BMD occur after cessation of growth, but continuation of hGH treatment after final height achievement may prevent the late osteopenia of patients with childhood-onset GHD.

Increase of a calcium independent transglutaminase activity in the erythrocyte during the infection with Plasmodium falciparum

We have studied the activity of a calcium dependent transglutaminase (EC 2.3.2.13) during the growth of the parasite Plasmodium falciparum inside the infected human erythrocyte. There is only one detectable transglutaminase in the two-cell-system, and its origin is erythrocytic. No activity was detected in preparations of the parasite devoid of erythrocyte cytoplasm. The Michaelis Menten constants (Km) of the enzyme for the substrates N'N' dimethylcaseine and putrescine were undistinguishable whether the cell extracts used in their determination were obtained from normal or from infected red cells. The total activity of transglutaminase in stringently synchronized cultures, measured at 0.5 mM Ca2+, decreased with the maturation of the parasite. However, a fraction which became irreversibly activated and independent of calcium concentration was detected. The proportion of this fraction grew with maturation; it represented only 20% of the activity in 20 hr-old-trophozoites while in 48-hr-schizonts it was more than 85% of the total activity. The activation of this fraction of transglutaminase did not depend on an increase in the erythrocyte cytoplasmic calcium, since most of the calcium was shown to be located in the parasite.

Production of IL-5 and granulocyte-macrophage colony-stimulating factor by naive human mast cells activated by high-affinity IgE receptor ligation

BACKGROUND

The late-phase allergic reaction is an eosinophilic inflammatory response that begins several hours after allergen exposure, may persist for 24 hours, and is an important pathogenic mechanism in allergic disease.

OBJECTIVE

Cultured naive human mast cells were used to investigate whether mast cells are a direct source of the eosinophil-promoting cytokines IL-5, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF).

METHODS

Naive human mast cells were derived from bone marrow mononuclear cells cultured in the presence of stem-cell factor. Cytokine message and protein production in response to high-affinity IgE receptor ligation of cultured mast cells were measured by semiquantitative polymerase chain reaction and ELISA, respectively.

RESULTS

IL-5, IL-3, and GM-CSF messenger RNA increased within 2 hours of mast cell activation, with IL-5 and GM-CSF message remaining elevated for 24 hours, whereas IL-3 mRNA rapidly declined. IL-5 and GM-CSF protein were measurable 4 to 6 hours after stimulation and peaked by 24 and 12 hours, respectively. IL-3 protein was not detectable.

CONCLUSION

These findings demonstrate that naive mast cells do not constitutively produce IL-5 or GM-CSF protein but are a major source of these eosinophilotropic cytokines on high-affinity IgE receptor ligation.

Two types of growth hormone rhythm in boys with constitutional short stature

The relationship between temporal and quantitative changes in pulsatile growth hormone (GH) secretion and growth of constitutionally short children (CSS) was studied in 19 prepubertal boys and 4 with early adrenarche aged 7.8 to 14 years. Continuous plasma GH monitoring was performed at 30 minutes intervals during 24 hours. The data were analysed by single and serial best fit (BFT) cosinor analysis for rhythm parameters and the Pulsar peak detection program for determining pulsatile properties. The pulsatile patterns were expressed in mean GH concentration, area under the curve, mean pulse area and maximal pulse height but not in the number of pulses. Thirteen out of 23 patterns exhibited significant 24-h compatible rhythms. The studied cohort was divided into two groups, those who exhibited the 24-h circadian rhythm (CIR) and those who lacked it (NCIR). Ultradian 2.5-4 h rhythms were observed in all patients. The NCIR children were significantly shorter than the CIR group (p = 0.017). The CIR boys secreted a significantly higher (p = 0.01) amount of GH during the 24-h span, most of which was during sleep. Our data indicate that the magnitude of pulses rather than their number is responsible for the quantitative differences observed between the two groups of boys with CSS. It is suggested that a lack of 24-h rhythmicity and the associated reduced nocturnal pulsatility play a role in the manifestation of short stature.

Detection of Genomic Polymorphism in Plasmodium falciparum using an arbitrarily primed PCR assay

Modifications of the arbitrarily primed polymerase chain reaction assay (i.e. a low annealing temperature and a very slow increase in the temperature during the elongation steps during the amplification cycles) allowed it to be used with the AT-rich Plasmodium falciparum DNA. The analysis of the products by polyacrylamide-urea gels, after silver staining, resulted in high resolution and sensitivity. Eighteen single and six combined pairs of arbitrary primers were tested. Two produced polymorphic patterns complex enough to differentiate between close Colombian isolates in a single assay. This method may be useful in studying the distribution and migration of strains in endemic areas, and for identifying intralaboratory cross-contamination of cultures.

Intraerythrocytic calcium chelators inhibit the invasion of Plasmodium falciparum

Calcium is an important factor in the invasion of the erythrocyte by Plasmodium falciparum. We have proposed that the entrance of the cation into the erythrocyte might be a messenger that triggers a series of molecular events leading to invasion. Other authors have proposed that the site of action of the calcium is extracellular. We show herein that the invasion is inhibited by intracellular calcium chelators and that the inhibition depends on the intracellular concentration of the chelators and on the calcium concentration in the medium.

Stage-specific expression of the calmodulin gene in Plasmodium falciparum

We studied the synthesis of calmodulin mRNA and of calmodulin during the asexual cell cycle of Plasmodium falciparum. The expression of the gene was low during the early stages of the erythrocytic asexual cycle. When the parasites were 28 h old the level of mRNA increased steadily to reach a peak at the age of 40 h. During the last 8 h of the cycle a constant decrease in the amount of calmodulin mRNA was observed. The synthesis of the protein followed the expression pattern of the mRNA, but without the final decrease. The average amounts of calmodulin measured were 2.5 +/- 0.9 ng/10(8) 14-h-old rings, 4.38 +/- 0.35 ng/10(8) 36-h-old trophozoites, 11.8 +/- 1.45 ng/10(8) 44-h-old trophozoites, and 19.6 +/- 1.9 ng/10(8) 48-h-old schizonts. The in vivo stability of mRNA in different developmental stages was evaluated by pulse and chase experiments. The RNA of very mature trophozoites was quickly degraded, in contrast with the high stability shown by the RNA in other stages. The results here suggest that the calmodulin gene expression in Plasmodium does not follow a housekeeping pattern of expression such as in other eukaryotic cells, but that it is regulated at the level of transcription and RNA degradation.

Mathematical formulae for the prediction of the residual beta cell function during the first two years of disease in children and adolescents with insulin-dependent diabetes mellitus

On the basis of a retrospective study of 71 children followed for 24 months after diagnosis of type I insulin dependent diabetes a fitted mathematical model was constructed for the prediction of the course of beta cell function from the time of diagnosis. Two equations were derived, one for the maximal basal (B-max) and the other for the maximal i.v. glucagon stimulated peak C-peptide (P-max) levels reached during the remission period. The prognostic variables selected for analysis were: peak C-peptide levels at diagnosis (Po), age sex, degree of obesity, pubertal rating, the presence of islet cell antibodies (ICA) and levels of GHb. Multivariate analysis of the data showed that Po (p = 0.0006), puberty (p = 0.041). obesity (p = 0.0021), sex (p = 0.031), ICA (p = 0.0045) and GHb(p = 0.0066) significantly contributed to the prediction formula obtained for B-max whereas the contribution of the above variables for P-max were: Po (p = 0.0019), puberty (p = 0.0187), obesity (p = 0.0058), sex (p = 0.0598), ICA (p = 0.0187) and GHb (p = 0.0027). The residuals of the observed values from the values fitted by the predicted equations served to define two separate groups demonstrating distinct differences in the natural course of beta cell function in type I diabetes. This fitted model may thus be useful in distinguishing between newly diagnosed young patients who will undergo remission, requiring lower insulin doses, and those who have little chance for remission. It might also be helpful in the selection of patients most likely to benefit from immunosuppression or modulation, to maximize the benefit to risk ratio for such patients.

Plasmodium falciparum: characterization of a 0.7-kbp, moderately repetitive sequence

A 692-bp-long repetitive sequence of Plasmodium falciparum was cloned. Two contiguous repeats were sequenced. The homology between them was 85%, the differences being due only to base replacements. The sequence was found 60 times repeated in the genome and was detected in 11 of 14 chromosomes. When used as a probe, the cloned fragment detected the parasite with the same sensitivity the 21-bp repeat (pRepHind) did. PCR amplification detected 0.02 pg of DNA, equivalent to a single parasite, in strains from America, Asia, and Africa. The restriction patterns were polymorphic and different among the strains. Analysis of lambda EMBL clones that contain the repetitive sequence confirms that it is present in various genomic contexts and is located subtelomerically.

Electrophoretic size separation of proteins treated with sodium dodecyl sulfate in 1% agarose gels

Separation of proteins treated with sodium dodecyl sulfate (SDS) according to molecular size was achieved by discontinuous electrophoresis in vertical low-concentration agarose gels. A linear relationship was found between the migration distance and the square root of the molecular weight. This holds for proteins in the range of 7-200 kDa separated in 1.25% w/v agarose gel slabs (7 x 7 x 0.15 cm) with 0.1% w/v SDS and sulfate as leading ion. The linear regression coefficient was 0.998. The molecular weight and charge of coions influenced the separation. Small ions with low pKa values were found suitable as coions. The migration distance of proteins treated with SDS varied linearly with the agarose concentration of the gel. The agarose type and quality affected the resolution of the SDS-protein bands. We conclude that agarose gels can substitute polyacrylamide gels for the separation of proteins treated with SDS. A homogeneous agarose gel at a concentration of about 1% is a nonsieving support for electrophoresis. Therefore, the separation described here cannot be explained by the pore size of the gel. The results suggest that the separation is mainly due to the relative migration velocities of the coion and the proteins treated with SDS.

Long-term uncoupling of chloride secretion from intracellular calcium levels by Ins(3,4,5,6)P4

Osmoregulation, inhibitory neurotransmission and pH balance depend on chloride ion (Cl-) flux. In intestinal epithelial cells, apical Cl- channels control salt and fluid secretion and are, in turn, regulated by agonists acting through cyclic nucleotides and internal calcium ion concentration ([Ca2+]i). Recently, we found that muscarinic pretreatment prevents [Ca2+]i increases from eliciting Cl- secretion in T84 colonic epithelial cells. By studying concomitant inositol phosphate metabolism, we have now identified D-myo-inositol 3,4,5,6-tetrakisphosphate (Ins(3,4,5,6)P4), as the inositol phosphate most likely to mediate this uncoupling. A novel, membrane-permeant ester prepared by total synthesis delivers Ins(3,4,5,6)P4 intracellularly and confirms that this emerging messenger does inhibit Cl- flux resulting from thapsigargin- or histamine-induced [Ca2+]i elevations.

Comparative effects of GH, IGF-I and insulin on serum sex hormone binding globulin

OBJECTIVE

The serum level of sex hormone binding globulin (SHBG) changes inversely with that of both insulin and insulin-like growth factor (IGF-I), during several nutritional conditions, as well as in response to GH treatment. However, with exogenous IGF-I administration, endogenous IGF-I increases, while insulin decreases. In order to study the separate roles of these hormones in controlling SHBG metabolism, we compared SHBG levels in patients treated with IGF-I and GH.

DESIGN AND PATIENTS

Serum levels of IGF-I, insulin and SHBG were measured before and during the treatment of patients with IGF-I or GH. Blood samples were drawn in the fasting state, prior to and during therapy, 24 hours after drug administration. Sixteen children and adults with Laron syndrome (LS) received daily s.c. injections of IGF-I (120-150 micrograms/kg) for up to 5 months. Three adults with isolated GH deficiency (IGHD) received daily s.c. injections of GH (0.03-0.06 U/kg) for 16 months. Two groups of nine prepubertal children with constitutional short stature (CSS) received GH (0.1 U/kg/day) for 3 months.

MEASUREMENTS

Serum levels of insulin and acid extractable IGF-I were determined by RIA, and that of SHBG by IRMA.

RESULTS

Basal insulin and SHBG levels were within normal range in the LS, IGHD and CSS patients. IGF-I levels were low in LS and IGHD patients, and normal in the CSS children. The mean peak response to chronic therapy was as follows: in LS patients, IGF-I administration decreased insulin levels to 62%, and increased SHBG levels by 64% above basal values. Chronic GH therapy in IGHD caused a marked rise in both IGF-I levels (473%), and insulin levels (96%), and a gradual decline of SHBG to 75% of the basal concentration. In GH treated CSS patients, serum IGF-I peaked at 80% and insulin levels at 102% above the respective basal levels, while SHBG decreased to 83% after 5 days of treatment.

CONCLUSION

The results obtained in Laron syndrome, isolated GH deficiency and constitutional short stature patients treated with IGF-I or GH, indicate that serum insulin had consistently an inverse relation with the levels of circulating SHBG. No relation was found between IGF-I and SHBG levels.

Evolutionary cytogenetics of the Drosophila buzzatii species complex

The salivary gland chromosomes of 10 species in the Drosophila mulleri subgroup (repleta group) have been re-analysed. These include the eight members of the South American buzzatti and martensis clusters, previously ascribed to the mulleri complex, and the two Caribbean species D. stalkeri and D. richardsoni, previously comprising the stalkeri complex. The chief results can be summarized as follows. Inversion 3a is not present in the martensis cluster. Hence, there is no cytological link between this cluster, or the buzzatii cluster, and the rest of the mulleri complex. Accordingly, a new species complex, the buzzatii complex, is established with the two South American clusters. D. stalkeri and D. richardsoni share at least two inversions with all the species in the buzzatii and martensis clusters, and produce hybrids in interspecific crosses with many of them. This indicates a close phylogenetic relationship. Therefore, D. stalkeri and D. richardsoni are incorporated as a cluster within the newly erected buzzatii complex. A phylogenetic tree illustrating the chromosomal evolution of the buzzatii complex is presented and all the previous cytological information concerning its members is reviewed.

Effect of low temperature on the in vitro growth of Plasmodium falciparum

The effect of low incubation temperature on synchronized cultures of Plasmodium falciparum was studied. Young trophozoites that were maintained at 28 degrees C matured slowly and invaded poorly. Growth seemed to arrest when parasites reached a maturation equivalent to 30 h, although they reestablished their growth normally when returned to 37 degrees C. On the other hand, 36-h synchronized parasites that were transferred to 28 degrees C completed their cell cycle with a 12-16 h delay, but without changes in the parasite as seen by light microscopy and without a diminution in the efficiency of the invasion or in the incorporation of 35S-methionine. These results might be useful for obtaining parasites at defined stages of development at the desired time.