Effects of exogenous GIP and GLP-2 on bone turnover in individuals with type 2 diabetes

CONTEXT

Individuals with type 2 diabetes (T2D) have an increased risk of bone fractures despite normal or increased bone mineral density (BMD). The underlying causes are not well understood but may include disturbances in the gut-bone axis, in which both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) are regulators of bone turnover. Thus, in healthy fasting participants, both exogenous GIP and GLP-2 acutely reduce bone resorption.

OBJECTIVE

The objective of this study was to investigate the acute effects of subcutaneously administered GIP and GLP-2 on bone turnover in individuals with T2D.

METHODS

We included 10 men with T2D. Participants met fasting in the morning on three separate test days and were injected subcutaneously with GIP, GLP-2, or placebo in a randomized crossover design. Blood samples were drawn at baseline and regularly after injections. Bone turnover was estimated by circulating levels of collagen type 1 C-terminal telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), sclerostin, and PTH.

RESULTS

GIP and GLP-2 significantly reduced CTX to (mean ± SEM) 66 ± 7.8% and 74 ± 5.9% of baseline, respectively, compared with after placebo (p = 0.001). In addition, P1NP and sclerostin increased acutely after GIP whereas a decrease in P1NP was seen after GLP-2. PTH levels decreased to 67 ± 2.5% of baseline after GLP-2 and to only 86 ± 3.4% after GIP.

CONCLUSION

Subcutaneous GIP and GLP-2 affect CTX and P1NP in individuals with T2D to the same extent as previously demonstrated in healthy individuals.

Influenza A subtype H3N2 is associated with an increased risk of hospital dissemination - an observational study over six influenza seasons

BACKGROUND

Previous studies on hospital-acquired influenza (HAI) have not systematically evaluated the possible impact of different influenza subtypes. HAI has historically been associated with high mortality, but clinical consequences may be less severe in a modern hospital setting.

AIMS

To identify and quantify HAI for each season, investigate possible associations with varying influenza subtypes, and to determine HAI-associated mortality.

METHODS

All influenza-PCR-positive adult patients (>18 years old) hospitalized in Skåne County during 2013-2019, were prospectively included in the study. Positive influenza samples were subtyped. Medical records of patients with suspected HAI were examined to confirm a nosocomial origin and to determine 30-day mortality.

RESULTS

Of 4110 hospitalized patients with a positive influenza PCR, 430 (10.5%) were HAI. Influenza A(H3N2) infections were more often HAI (15.1%) than influenza A(H1N1)pdm09, and influenza B (6.3% and 6.8% respectively, P<0.001). The majority of HAI caused by H3N2 were clustered (73.3 %) and were the cause of all 20 hospital outbreaks consisting of ≥4 affected patients. In contrast, the majority of HAI caused by influenza A(H1N1)pdm09 and influenza B were solitary cases (60% and 63.2%, respectively, P<0.001). Mortality associated with HAI was 9.3% and similar between subtypes.

CONCLUSIONS

HAI caused by influenza A(H3N2) was associated with an increased risk of hospital dissemination. Our study is relevant for future seasonal influenza infection control preparedness and shows that subtyping of influenza may help to define relevant infection control measures. Mortality in HAI remains substantial in a modern hospital setting.

GLP-1 Val8: A Biased GLP-1R Agonist with Altered Binding Kinetics and Impaired Release of Pancreatic Hormones in Rats

Biased ligands that selectively confer activity in one pathway over another are pharmacologically important because biased signaling may reduce on-target side effects and improve drug efficacy. Here, we describe an N-terminal modification in the incretin hormone glucagon-like peptide (GLP-1) that alters the signaling capabilities of the GLP-1 receptor (GLP-1R) by making it G protein biased over internalization but was originally designed to confer DPP-4 resistance and thereby prolong the half-life of GLP-1. Despite similar binding affinity, cAMP production, and calcium mobilization, substitution of a single amino acid (Ala8 to Val8) in the N-terminus of GLP-1(7-36)NH₂ (GLP-1 Val8) severely impaired its ability to internalize GLP-1R compared to endogenous GLP-1. In-depth binding kinetics analyses revealed shorter residence time for GLP-1 Val8 as well as a slower observed association rate. Molecular dynamics (MD) displayed weaker and less interactions of GLP-1 Val8 with GLP-1R, as well as distinct conformational changes in the receptor compared to GLP-1. In vitro validation of the MD, by receptor alanine substitutions, confirmed stronger impairments of GLP-1 Val8-mediated signaling compared to GLP-1. In a perfused rat pancreas, acute stimulation with GLP-1 Val8 resulted in a lower insulin and somatostatin secretion compared to GLP-1. Our study illustrates that profound differences in molecular pharmacological properties, which are essential for the therapeutic targeting of the GLP-1 system, can be induced by subtle changes in the N-terminus of GLP-1. This information could facilitate the development of optimized GLP-1R agonists.

Secretin release after Roux-en-Y gastric bypass reveals a population of glucose-sensitive S cells in distal small intestine

OBJECTIVES

Gastrointestinal hormones contribute to the beneficial effects of Roux-en-Y gastric bypass surgery (RYGB) on glycemic control. Secretin is secreted from duodenal S cells in response to low luminal pH, but it is unknown whether its secretion is altered after RYGB and if secretin contributes to the postoperative improvement in glycemic control. We hypothesized that secretin secretion increases after RYGB as a result of the diversion of nutrients to more distal parts of the small intestine, and thereby affects islet hormone release.

METHODS

A specific secretin radioimmunoassay was developed, evaluated biochemically, and used to quantify plasma concentrations of secretin in 13 obese individuals before, 1 week after, and 3 months after RYGB. Distribution of secretin and its receptor was assessed by RNA sequencing, mass-spectrometry and in situ hybridization in human and rat tissues. Isolated, perfused rat intestine and pancreas were used to explore the molecular mechanism underlying glucose-induced secretin secretion and to study direct effects of secretin on glucagon, insulin, and somatostatin secretion. Secretin was administered alone or in combination with GLP-1 to non-sedated rats to evaluate effects on glucose regulation.

RESULTS

Plasma postprandial secretin was more than doubled in humans after RYGB (P < 0.001). The distal small intestine harbored secretin expressing cells in both rats and humans. Glucose increased the secretion of secretin in a sodium-glucose cotransporter dependent manner when administered to the distal part but not into the proximal part of the rat small intestine. Secretin stimulated somatostatin secretion (fold change: 1.59, P < 0.05) from the perfused rat pancreas but affected neither insulin (P = 0.2) nor glucagon (P = 0.97) secretion. When administered to rats in vivo, insulin secretion was attenuated and glucagon secretion increased (P = 0.04), while blood glucose peak time was delayed (from 15 to 45 min) and gastric emptying time prolonged (P = 0.004).

CONCLUSIONS

Glucose-sensing secretin cells located in the distal part of the small intestine may contribute to increased plasma concentrations observed after RYGB. The metabolic role of the distal S cells warrants further studies.

CCK-1 and CCK-2 receptor agonism do not stimulate GLP-1 and neurotensin secretion in the isolated perfused rat small intestine or GLP-1 and PYY secretion in the rat colon

Gastrin and cholecystokinin (CCK) are hormones released from endocrine cells in the antral stomach (gastrin), the duodenum, and the jejunum (CCK). Recent reports, based on secretion experiments in an enteroendocrine cell line (NCI-H716) and gastrin receptor expression in proglucagon-expressing cells from the rat colon, suggested that gastrin could be a regulator of glucagon-like peptide-1 (GLP-1) secretion. To investigate these findings, we studied the acute effects of CCK-8 (a CCK1/CCK2 (gastrin) receptor agonist) and gastrin-17 (a CCK2(gastrin) receptor agonist) in robust ex vivo models: the isolated perfused rat small intestine and the isolated perfused rat colon. Small intestines from Wistar rats (n = 6), were perfused intraarterially over 80 min. During the perfusion, CCK (1 nmol/L) and gastrin (1 nmol/L) were infused over 10-min periods separated by washout/baseline periods. Colons from Wistar rats (n = 6) were perfused intraarterially over 100 min. During the perfusion, CCK (1 nmol/L), vasoactive intestinal peptide (VIP) (10 nmol/L), and glucose-dependent insulinotropic polypeptide (GIP) (1 nmol/L) were infused over 10-min periods separated by washout/baseline periods. In the perfused rat small intestines neither CCK nor gastrin stimulated the release of GLP-1 or neurotensin. In the perfused rat colon, neither CCK or VIP stimulated GLP-1 or peptide YY (PYY) release, but GIP stimulated both GLP-1 and PYY release. In both sets of experiments, bombesin, a gastrin-releasing peptide analog, served as a positive control. Our findings do not support the suggestion that gastrin or CCK participate in the acute regulation of intestinal GLP-1 secretion, but that GIP may play a role in the regulation of hormone secretion from the colon.

Acute administration of interleukin-6 does not increase secretion of glucagon-like peptide-1 in mice

Interleukin 6 (IL‐6) is a cytokine secreted from skeletal muscle in response to exercise which, based on animal and cell studies, has been suggested to contribute to glucose metabolism by increasing secretion of the incretin hormone glucagon‐like peptide‐1 (GLP‐1) and affecting secretion of insulin and glucagon from the pancreatic islets. We investigated the effect of IL‐6 on GLP‐1 secretion in GLP‐1 producing cells (GLUTag) and using the perfused mouse small intestine (harboring GLP‐1 producing cells). Furthermore, the direct effect of IL‐6 on insulin and glucagon secretion was studied using isolated perfused mouse pancreas. Incubating GLUTag cells with 1000 ng/mL of IL‐6 for 2 h did not significantly increase secretion of GLP‐1 whereas 10 mmol/L glucose (positive control) did. Similarly, IL‐6 (100 ng/mL) had no effect on GLP‐1 secretion from perfused mouse small intestine whereas bombesin (positive control) increased secretion. Finally, administering IL‐6 (100 ng/mL) to perfused mouse pancreases did not significantly increase insulin or glucagon secretion regardless of perfusate glucose levels (3.5 vs. 12 mmol/L glucose). Acute effects of IL‐6 therefore do not seem to include a stimulatory effect on GLP‐1 secretion in mice.

On the relationship between glucose absorption and glucose-stimulated secretion of GLP-1, neurotensin, and PYY from different intestinal segments in the rat

Ingested glucose powerfully stimulates the secretion of appetite‐ and metabolism‐regulating peptide hormones from the gut – including glucagon‐like peptide‐1 (GLP‐1), neurotensin (NT), and polypeptide YY (PYY). However, the regional origin of these secretions after glucose stimulation is not well characterized, and it remains uncertain how their secretion is related to glucose absorption. We isolated and perfused either the upper (USI) or the lower (LSI) small intestine or the colon from rats and investigated concomitant glucose absorption and secretory profiles of GLP‐1, NT, and PYY. In the USI and LSI luminal glucose (20%, w/v) increased GLP‐1 and NT secretion five to eightfold compared to basal secretion. Compared to the USI, basal and stimulated GLP‐1 secretion from the colon was 8–10 times lower and no NT secretion was detected. Luminal glucose stimulated secretion of PYY four to fivefold from the LSI and from the USI and colon, but the responses in the USI and colon were 5‐ to 15‐fold lower than in the LSI. Glucose was absorbed to a comparable extent in the USI and LSI by mechanisms that partly depended on both SGLT1 and GLUT2 activity, whereas the absorption in the colon was 80–90% lower. The absorption rates were, however, similar when adjusted for segmental length. Glucose absorption rates and NT, PYY and in particular GLP‐1 secretion were strongly correlated (P < 0.05). Our results indicate that the rate of secretion of GLP‐1, NT, and PYY in response to glucose, regardless of the involved molecular machinery, is predominantly regulated by the rate of glucose absorption.

Glucagon-like Peptide 1 Receptor Signaling in Acinar Cells Causes Growth-Dependent Release of Pancreatic Enzymes

Incretin-based therapies are widely used for type 2 diabetes and now also for obesity, but they are associated with elevated plasma levels of pancreatic enzymes and perhaps a modestly increased risk of acute pancreatitis. However, little is known about the effects of the incretin hormone glucagon-like peptide 1 (GLP-1) on the exocrine pancreas. Here, we identify GLP-1 receptors on pancreatic acini and analyze the impact of receptor activation in humans, rodents, isolated acini, and cell lines from the exocrine pancreas. GLP-1 did not directly stimulate amylase or lipase release. However, we saw that GLP-1 induces phosphorylation of the epidermal growth factor receptor and activation of Foxo1, resulting in cell growth with concomitant enzyme release. Our work uncovers GLP-1-induced signaling pathways in the exocrine pancreas and suggests that increases in amylase and lipase levels in subjects treated with GLP-1 receptor agonists reflect adaptive growth rather than early-stage pancreatitis.

Sweet Taste Receptor Activation in the Gut Is of Limited Importance for Glucose-Stimulated GLP-1 and GIP Secretion

Glucose stimulates the secretion of the incretin hormones: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). It is debated whether the sweet taste receptor (STR) triggers this secretion. We investigated the role of STR activation for glucose-stimulated incretin secretion from an isolated perfused rat small intestine and whether selective STR activation by artificial sweeteners stimulates secretion. Intra-luminal administration of the STR agonists, acesulfame K (3.85% w/v), but not sucralose (1.25% w/v) and stevioside (2.5% w/v), stimulated GLP-1 secretion (acesulfame K: 31 ± 3 pmol/L vs. 21 ± 2 pmol/L, p < 0.05, n = 6). In contrast, intra-arterial administration of sucralose (10 mM) and stevioside (10 mM), but not acesulfame K, stimulated GLP-1 secretion (sucralose: 51 ± 6 pmol/L vs. 34 ± 4 pmol/L, p < 0.05; stevioside: 54 ± 6 pmol/L vs. 32 ± 2 pmol/L, p < 0.05, n = 6), while 0.1 mM and 1 mM sucralose did not affect the secretion. Luminal glucose (20% w/v) doubled GLP-1 and GIP secretion, but basolateral STR inhibition by gurmarin (2.5 µg/mL) or the inhibition of the transient receptor potential cation channel 5 (TRPM5) by triphenylphosphine oxide (TPPO) (100 µM) did not attenuate the responses. In conclusion, STR activation does not drive GIP/GLP-1 secretion itself, nor does it have a role for glucose-stimulated GLP-1 or GIP secretion.

GLP1- and GIP-producing cells rarely overlap and differ by bombesin receptor-2 expression and responsiveness

The incretin hormones glucagon-like peptide-1 (GLP1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from intestinal endocrine cells, the so-called L- and K-cells. The cells are derived from a common precursor and are highly related, and co-expression of the two hormones in so-called L/K-cells has been reported. To investigate the relationship between the GLP1- and GIP-producing cells more closely, we generated a transgenic mouse model expressing a fluorescent marker in GIP-positive cells. In combination with a mouse strain with fluorescent GLP1 cells, we were able to estimate the overlap between the two cell types. Furthermore, we used primary cultured intestinal cells and isolated perfused mouse intestine to measure the secretion of GIP and GLP1 in response to different stimuli. Overlapping GLP1 and GIP cells were rare (∼5%). KCl, glucose and forskolin+IBMX increased the secretion of both GLP1 and GIP, whereas bombesin/neuromedin C only stimulated GLP1 secretion. Expression analysis showed high expression of the bombesin 2 receptor in GLP1 positive cells, but no expression in GIP-positive cells. These data indicate both expressional and functional differences between the GLP1-producing 'L-cell' and the GIP-producing 'K-cell'.

The VGF-Derived Neuropeptide TLQP-21 Shows No Impact on Hormone Secretion in the Isolated Perfused Rat Pancreas

TLQP-21 is a VGF-derived neuropeptide proposed to be involved in regulation of metabolism. More specifically it has been suggested that TLQP-21 has the ability to enhance glucose stimulated insulin secretion, making it a candidate for treatment of patients with type 2 diabetes.In this study, we investigated the impact of TLQP-21 on insulin, glucagon, and somatostatin secretion in the perfused rat pancreas. We found that administration of 5 and 50 nM TLQP-21 had no impact on pancreatic hormone secretion at 3.5 or 8 mM glucose levels. Increasing TLQP-21 (200 nM) and glucose concentration (3.5 and 16 mM) led to a nonsignificant decrease in glucagon secretion, though insulin and somatostatin secretory patterns remained unaffected. In a final set of experiments, perfusions were performed with infusion of 50 and 1 000 nM TLQP-21 to ensure sufficient stimulation. However, administration of TLQP-21 under this setup showed no impact on the pancreatic hormone secretion either. In conclusion, the outcome of this study does not concur with previous findings, suggesting that the effect of TLQP-21 does not directly involve silent hormone secretion.

Emergence of enterovirus D68 in Denmark, June 2014 to February 2015

From June 2014 through February 2015, respiratory samples from 130 Danish patients were screened for enterovirus D68 (EV-D68). Fourteen EV-D68 cases were detected, of which 12 presented with respiratory symptoms, and eight had known underlying disease. The median age of EV-D68 cases was three years (interquartile range: 0–30 years). Acute flaccid paralysis (AFP) was not detected although Danish EV-D68 strains showed > 98% nt identity with EV-D68-strains from AFP cases from the United States and France.

Cardiovascular risk in patients with sleep apnoea with or without continuous positive airway pressure therapy: follow-up of 4.5 million Danish adults

BACKGROUND

The prognostic significance of age and continuous positive airway pressure (CPAP) therapy on cardiovascular disease in patients with sleep apnoea has not been assessed previously.

METHODS

Using nationwide databases, the entire Danish population was followed from 2000 until 2011. First-time sleep apnoea diagnoses and use of CPAP therapy were determined. Incidence rate ratios (IRRs) of ischaemic stroke and myocardial infarction (MI) were analysed using Poisson regression models.

RESULTS

Amongst 4.5 million individuals included in the study, 33 274 developed sleep apnoea (mean age 53, 79% men) of whom 44% received persistent CPAP therapy. Median time to initiation of CPAP therapy was 88 days (interquartile range 34-346). Patients with sleep apnoea had more comorbidities compared to the general population. Crude rates of MI and ischaemic stroke were increased for sleep apnoea patients (5.4 and 3.6 events per 1000 person-years compared to 4.0 and 3.0 in the general population, respectively). Relative to the general population, risk of MI [IRR 1.71, 95% confidence interval (CI) 1.57-1.86] and ischaemic stroke (IRR 1.50, 95% CI 1.35-1.66) was significantly increased in patients with sleep apnoea, in particular in patients younger than 50 years (IRR 2.12, 95% CI 1.64-2.74 and IRR 2.34, 95% CI 1.77-3.10, respectively). Subsequent CPAP therapy was not associated with altered prognosis.

CONCLUSIONS

Sleep apnoea is associated with increased risk of ischaemic stroke and MI, particularly in patients younger than 50 years of age. CPAP therapy was not associated with a reduced rate of stroke or MI.

Retinal vein and artery occlusions: a risk factor for stroke in atrial fibrillation

BACKGROUND

Retinal vascular occlusions may constitute an independent risk factor for stroke in patients with atrial fibrillation.

METHODS

We performed a retrospective study on a nationwide cohort with atrial fibrillation from 1997 to 2008. The rate of stroke/systemic thromboembolism (TE)/transitory ischemic attack (TIA) was determined for atrial fibrillation patients with and without a history of retinal vascular occlusion. A Cox regression analysis, adjusted for risk factors and medications, was performed to determine the independent predictive value of retinal arterial or venous occlusion for the risk of ischemic stroke, TE or TIA in atrial fibrillation patients.

RESULTS

We included 87 202 patients with non-valvular atrial fibrillation. At baseline, a history of retinal arterial occlusion was diagnosed in 224 patients (0.26%) and a history of retinal venous occlusion in 361 (0.41%). Patients without retinal occlusion had a rate of stroke/TE/TIA of 4.52 (95% confidence interval [CI] 4.44-4.60). For patients with retinal arterial occlusion, the rate of stroke/TE/TIA was 8.16 (95% CI 6.35-10.49) per 100 person-years, and for patients with retinal venous occlusion it was 7.28 (95% CI 5.93-8.94) per 100 person-years. In multivariate analysis, both retinal arterial occlusions (hazard ratio [HR] 1.39, 95% CI 1.08-1.79) and retinal venous occlusions (HR 1.26, 95% CI 1.02-1.54) were associated with an increased risk of future stroke/TE/TIA.

CONCLUSIONS

A history of retinal arterial or retinal venous occlusion is associated with an increased risk of stroke/TE/TIA in patients with atrial fibrillation. Thus, prior retinal vascular occlusion may be considered as a previous thromboembolic event when evaluating stroke risk in patients with atrial fibrillation.

Prevalence of sexually transmitted infections among women attending antenatal clinics in Tanga, north eastern Tanzania

This study aimed to determine the prevalence of sexually transmitted infections (STIs) among HIV-infected and uninfected pregnant women in Tanga, Tanzania. Retrospective data on syphilis and HIV status during 2008-2010 were collected from antenatal clinic (ANC) records. Prospective data were collected from HIV-infected (n = 105) and HIV-uninfected pregnant women (n = 100) attending ANCs between April 2009 and August 2010. Syphilis prevalence showed a declining trend (3.1%, 1.4% and 1.3%), while HIV prevalence was stable (6.1%, 6.4% and 5.4%) during 2008-2010. HIV-infected women had significantly higher prevalence of trichomoniasis (18.8% versus 5.0%; P < 0.003) and candidiasis (16.5% versus 2.0%; P < 0.001) while the higher rate of gonorrhoea (3.5% versus 0%; P = 0.095) was not statistically significant when compared with HIV-uninfected women. There were no statistically significant differences in prevalence of chlamydial infection (0% versus 3.0%; P = 0.156) or syphilis (2.4% versus 3.0%; P = 1) between HIV-infected and uninfected women. Other STIs were common in both HIV-infected and uninfected pregnant women.

First identification of tick-borne encephalitis in Denmark outside of Bornholm, August 2009

The incidence of tick-borne encephalitis (TBE) in Scandinavia is increasing and spreading geographically. Following two clinical cases of TBE hospitalised after tick bites in northern Zealand, Denmark, specific IgM and IgG antibodies against tick-borne encephalitis virus (TBEV) were demonstrated in acute serum samples of these patients. TBEV was identified by RT-PCR in ticks collected from the same location. This is the first report of TBEV in Ixodes ricinus leading to clinical cases in Denmark outside of Bornholm island.

[Population screening for HIV in Sisimiut, Greenland]

INTRODUCTION

In the years 1985-1998, 91 HIV-positive persons were diagnosed in Greenland, resulting in an incidence of HIV infection three times higher in Greenland than in Denmark. Of these cases 25% were diagnosed in Sisimiut, which, however, only comprises 10% of the total population of Greenland. In spite of an active HIV case-tracing programme at the Health Centre, there was a fear of unknown HIV-positives in the town. Therefore, the Health Centre initiated an HIV screening campaign among all adults and school children in the town of Sisimiut and two adjacent settlements.

MATERIAL AND METHODS

The screening campaign was carried out in the weeks 46 and 47 in November 1998 by the staff at the Health Centre. All participants filled out a questionnaire concerning demographic variables, and had blood samples drawn. For adults the campaign mainly took place in the community centre and the large work places, and for the children at the schools. Blood samples were tested for antibodies against HIV 1 and 2 at Statens Serum Institut using ELISA tests and confirmatory Western Blot.

RESULTS

Of the total population of 4807, 2858 persons took part in the screening campaign (participation rate 59%). Among adults the participation rate was 50%, and for children aged 6-17 years the rate was 86%. Four HIV-positive persons were tested positive. Of these three were already known HIV-positives, and the last person was highly suspect of HIV infection.

DISCUSSION

There is no evidence of widespread HIV infection in Sisimiut. No unknown groups of HIV-positive persons were identified. Thus, the intensive case-tracing programme as carried out by the Health Centre seems effective.

EBV-positive primary central nervous system lymphomas in monozygote twins with common variable immunodeficiency and suspected multiple sclerosis

Common variable immunodeficiency represents the most frequently occurring primary immunodeficiency disorder and is usually detected sporadically in patients with no family history of immunodeficiency. We present the case stories of two monozygote twins, who following a period of decreasing serum immunoglobulins developed primary central nervous system lymphomas. One twin had clinical and paraclinical features mimicking multiple sclerosis. Immunohistochemical investigations on biopsy tissue showed expression of the bcl-2 and p53 gene products, and Epstein-Barr virus (EBV) encoded small RNA's (EBER) indicating latent infection were detected in lymphoma cells using in situ hybridisation techniques. The pathogenetic role of EBV in oncogenesis is discussed.

Markers of sexually transmitted diseases in seminal fluid of male clients of female sex workers

OBJECTIVES

To screen for certain STD markers in a group of male clients of female sex workers.

METHOD

Condoms with seminal fluid were collected at 10 "massage parlours" in Copenhagen. The seminal fluid samples were examined for HIV antibodies, markers of hepatitis B virus (HBV), Chlamydia trachomatis, and Mycoplasma genitalium.

RESULTS

All samples (n = 332) were negative for HIV antibodies. Out of 327 samples examined for HBV markers 32 (9.8%) were positive for HBV core antibodies, one of which was also positive for HBV antigen. C trachomatis could be demonstrated in six out of 122 (4.9%) samples and M genitalium in one out of 122 samples.

CONCLUSIONS

The finding of a C trachomatis prevalence of 4.9% is considerable higher than expected in men with a presumed age of 35-55 years. The demonstration of a prevalence of HBV markers of 9.8% indicates that these clients have an increased risk of HBV infection, a finding that further consolidates the recommendation of HBV vaccination of sex workers. As shown in this study, STD transmission in commercial sex may also have the client as the source.

9-year HIV-2-associated mortality in an urban community in Bissau, west Africa

BACKGROUND

Community studies with 1-3 years of follow-up have reported four to five times higher mortality in HIV-2-infected than in uninfected adults. In a cohort study of HIV-1, an increasing difference in mortality rates of HIV-1-infected and uninfected individuals is expected over time, because of rising mortality with advancing HIV-1 infection. We therefore investigated long-term survival of HIV-2-infected adults.

METHODS

Adults enrolled in 1987 in a community study of HIV-2 infection in Guinea-Bissau were followed up with serological surveys in 1989 and 1992. Survival was assessed in 1995, 9 years after enrollment.

FINDINGS

The annual incidence of HIV-2 was 0.7% for adults and tended to be higher for older individuals than for participants aged 15-44 years (relative risk 3.21 [95% CI 0.91-11.37]). With control for age, HIV-2-infected adults had twice as high mortality as uninfected individuals (mortality ratio 2.32 [1.18-4.57]); the mortality ratio was highest in the first year of the study (4.50 [1.31-15.43]). The difference between infected and uninfected individuals was stronger for adults under 45 years of age (mortality ratio 4.72 [1.86-11.97]) than for older people (1.35 [0.51-3.56]). HIV-2-infected individuals living with an infected spouse had significantly higher mortality than HIV-2-infected individuals living with an uninfected spouse (p = 0.027).

INTERPRETATION

HIV-2-associated mortality is not increasing with length of follow-up. Mortality in HIV-2-infected adults is only twice as high as that in uninfected individuals. In the majority of adults, HIV-2 has no effect on survival.

False negative anti-HIV-1/HIV-2 ELISAs in acute HIV-2 infection

Since HIV-2 was isolated in 1986, only 1 case of acute HIV-2 infection has been reported. We have identified another patient with primary HIV-2 infection. Follow-up samples were requested from the patient due to discrepant results. The HIV-2 infection was confirmed with HIV-2-specific proviral DNA amplification by PCR. The HIV-2 seroconversion panel obtained was used to evaluate the sensitivity of both combined and specific ELISAs currently in use in Europe, and to investigate the Western-blot patterns on both HIV-1-and HIV-2-specific Western blots. The window period was determined to be less than 37 days with the most sensitive assays. A remarkable difference in sensitivity to HIV-2 antibodies in acute HIV-2 infection was found in combined HIV-1/HIV-2 ELISAs. Three out of the 4 combined sandwich ELISAs appeared to be less sensitive than the indirect ELISAs in HIV-2 seroconversion, leading to a prolonged window period. One HIV-2-specific ELISA was also negative on the first sample, but positive on the second sample. In the HIV-2 Western blot, early reaction with HIV-2-specific env and gag proteins was seen, whereas the HIV-1 Western blot on the first sample revealed gag (p24, p55) reactivity only.

[Infection with human immunodeficiency virus type 2--HIV-2]

The majority of patients with HIV-2 infection come from West Africa or have had sexual contact with a person from there, as HIV-2 is prevalent in this area. HIV-2 is phylogenetically closer related to SIVsm and SIVmac than to HIV-1. HIV-2 is mainly transmitted by heterosexual contact, whereas the risk of mother-to-child infection is very low. Nine cases of HIV-2 infection have been diagnosed in Denmark. Out of these, seven are from West Africa and two have been infected in Denmark by individuals from West Africa.

[Human T-lymphotrophic virus type I and II--diagnosis and clinical presentation]

Human T-lymphotropic virus type 1, HTLV-I, was the first human oncogenic retrovirus to be isolated in 1978. HTLV-I has previously been called Human T-cell leukaemia virus or Human T-cell lymphoma virus type I. HTLV-I infection is endemic in southwestern Japan, the Caribbean basin, and parts of South America and Africa. HTLV-I is aetiologically associated with adult T-cell leukaemia lymphoma and tropical spastic paraparesis (TSP), also known as HTLV-I-associated myelopathy. HTLV-II was isolated in 1982 and is endemic among some north American Indians. HTLV-II has not been clearly linked to any specific disease. Both viruses are found worldwide, particularly among intravenous drug users (IVDU), and have also been found in blood donors in USA and Europe. HTLV-I/II are transmitted by the same routes as HIV-1: blood-borne via blood transfusions and among IVDUs by sharing contaminated needles, and by mother-to-child transmission, primarily through breast feeding. HTLV-I/II infections are also sexually transmitted and can be transmitted in utero, though less efficiently than HIV-1. The diagnosis of HTLV-I/II infections is based on the detection of antibody to the virus. Due to the high degree of cross reactivity between HTLV-I and HTLV-II, it is difficult by serology to discriminate between the two viruses. Less than 5% of individuals infected with HTLV-I develop symptoms after a latent period, which can last from a few years to several decades. No specific treatment of adult T-cell leukaemia or tropical spastic paraparesis is currently available and no vaccine has yet been developed.

[HIV infection in children]

More children will be born infected with HIV in the years to come. Children with early symptoms will come into quick contact with a hospital, while others may be infected for up to ten years without presenting HIV-related symptoms. HIV infection can be diagnosed early with a combination of methods that are currently available (viral culture, ELISA antigen testing), and also with methods that are at present only used in research (DNA and RNA detection with PCR). Together with the clinical picture, it should be possible to have a reliable diagnosis no later than six months after birth. The general development of the children can be followed at frequent out-patient visits, while prophylactic measures can quickly be put into motion when necessary. The course of the illness can be followed and predicted with the help of different laboratory investigations. The medical treatment of HIV positive children follows the pattern of adult HIV positive patients. Children with an increased risk of bacterial infections can receive intravenous immune globulin as prophylaxis. HIV infected children can be given the common vaccinations, but BCG and oral anti-polio vaccine should not be given to children with symptomatic HIV infection. Prophylaxis of vertical transmission of HIV should be aimed at HIV testing of all pregnant women, to prevent this route of transmission. As long as there is no efficient treatment of HIV infection, termination of pregnancy must be recommended early after conception to all HIV positive women. Children born of HIV positive mothers should not be breast-fed.

[Diagnosis of HIV-infection]

Different methods have been developed for the diagnosis of HIV infection, i.e. detection of antibodies, antigen and proviral DNA. ELISA methods for detecting HIV-1 antibodies are widely used as screening assays. A sample which is repeatedly positive with ELISA is re-tested with a confirmatory test, e.g. western blot. Antibodies to HIV-1 are not detectable until 2-3 months after infection, but antigens may be detectable during the last weeks of this initial period, though they disappear with the appearance of the antibodies. In the later stages of HIV infection, HIV antigen is again detectable in a proportion of patients. Detection and quantitation of HIV antigen are used as indicators of disease progression and for monitoring the antiviral efficacy of therapeutic interventions. When no antibodies or antigens can be detected in persons suspected of having HIV infection, culture of HIV can be performed. For research purposes, detection of small amounts of proviral DNA can be made with polymerase chain reaction (PCR). The method is not yet applicable in routine diagnosis of HIV infection.

Photography in treatment of tympanic membrane perforations

A photographic method which gives a large image on the film is used for recording perforations of the tympanic membrane and it may be valuable for comparing different methods of closure. A method for the treatment of minor perforations is also briefly mentioned.

Reversible hearing loss in tumours of the cerebello-pontine angle

A survey of the literature concerning reversible hearing loss in tumours of the cerebello-pontine angle is presented together with two additional cases. After removal of one meningioma and one epidermoid tumour, respectively, the abolished acoustico-vestibular function returned in both cases. The pre-requisites for the restoration of hearing are discussed.