Determinants of dysmenorrhoea among female adolescents: results from a community-based cohort study in Amsterdam

RESEARCH QUESTION

What is the contribution of sociodemographic, psychosocial, lifestyle and reproductive factors up to the age of 11-12 years to the occurrence of dysmenorrhoea at age 15-16 years within the Amsterdam Born Children and their Development (ABCD) study?

DESIGN

Data of 1038 female adolescents were used. Participants' baseline characteristics were obtained using self-reported questionnaires up to the age of 11-12 years, as well as the obstetric information of their mothers during pregnancy. Dysmenorrhoea was assessed at the age of 15-16 years, and was deemed to be present if an adolescent reported menstrual abdominal and/or back pain and therefore took medication and/or hormonal contraception. Using a backward selection approach, potential determinants of dysmenorrhoea were selected and multivariable associations were determined.

RESULTS

The overall prevalence of dysmenorrhoea was 49.5% among the participants. Intake of 3-4.5 sugar-sweetened beverages/day (P = 0.035) and higher gynaecological age (i.e. years since menarche) (P < 0.001) were significantly associated with higher occurrence of dysmenorrhoea in the final model, which explained 8.1% of the total variance in the occurrence of dysmenorrhoea. No significant associations were found between the occurrence of dysmenorrhoea and sociodemographic or psychosocial factors.

CONCLUSIONS

This investigation of various potential risk factors for dysmenorrhoea suggests that diet and reproductive factors are particularly important predictors of the occurrence of dysmenorrhoea among young adolescents. Specifically, intake of sugar-sweetened beverages and higher gynaecological age were predictive of the occurrence of dysmenorrhoea. Other lifestyle factors were also identified as possible risk factors. Using this knowledge, effective strategies can be developed to reduce the burden of dysmenorrhoea among adolescents, and to provide appropriate care for those suffering from the condition.

Validation of frailty assessment batteries in relation to prognosis in older patients with cardiovascular disease

Funding Acknowledgements

Type of funding sources: None.

Background

Frailty is accompanied by, or can be caused by, a combination of several physical, psychosocial and cognitive problems, and is highly prevalent in older patients with cardiovascular disease (CVD). However, different frailty assessment batteries (e.g. Fried and Vigorito) remain to be compared in terms of prognosis, as well as the subcomponents within those batteries.

Purpose

To examine which frailty measurements contribute to the prediction of frailty in CVD patients, and prognosis, and thus should be executed in clinical settings.

Methods

In 133 CVD patients (mean age 78.1 ± 6.7 years) the presence of frailty was examined by the Fried criteria and compared with the outcome from the multi-component frailty assessment tool of Vigorito including the Mini Nutritional Assessment (MNA), Katz-scale, 4.6 m gait speed, Timed Up and Go Test (TUG), handgrip strength, Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15) and number of medications. Additional tests were executed to further enhance the prediction of frailty. Patients were followed to register hospitalisations (general and urgent) and mortality up to 6 months after the frailty assessment. First, it was then analysed whether the Fried or Vigorito test battery would equally predict complications during follow-up, and secondly a new frailty test battery was developed with evaluation towards complication risk predictions.

Results

According to the tool of Vigorito, significantly more CVD patients suffered from minor vs. moderate frailty (34% vs. 10%, p &lt; 0.001) while the Phenotype of Fried did not succeed in detecting any significant difference in the number of pre-frail vs. frail patients (26% vs. 38%, p = 0.11). Moreover, the largest part of the pre-frail patients of Fried seems to be not frail according to Vigorito and the frail patients of Fried seems to be mainly minor frail according to Vigorito.

Significant associations were found between hospitalisations and frailty according to Fried while mortality was significantly associated with frailty according to Vigorito and the newly developed formula (p = 0.013). Finally, based on the multivariate regression model (R2 = 0.95), sex, MNA, Katz scale, TUG, handgrip strength (dominant hand), MMSE, GDS-15, total number of medications and the interaction effect between the Katz-scale and TUG should be assessed to detect frailty.  Based on these  parameters, a new formula to detect frailty was developed (r = 0.95 with Vigorito score, p &lt; 0.001).

Conclusions

In comparison with the frailty assessment tool of Vigorito, the Fried criteria may overestimate frailty and its severity. Moreover, frailty seems to be significantly associated with 6-months hospitalisations as well as with mortality. The newly developed frailty assessment battery has the potential to detect frailty in a multidimensional way, and, moreover, to predict mortality.

Pain-related beliefs are associated with arm function in persons with frozen shoulder

BACKGROUND

Frozen shoulder is a painful glenohumeral joint condition. Pain-related beliefs are recognized drivers of function in musculoskeletal conditions. This cross-sectional study investigates associations between pain-related beliefs and arm function in frozen shoulder.

METHODS

Pain intensity, arm function (Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH)), pain catastrophizing (Pain Catastrophizing Scale (PCS)), pain-related fear (Tampa Scale for Kinesiophobia (TSK-11)) and pain self-efficacy (Pain Self-Efficacy Questionnaire (PSEQ)) were administered in 85 persons with frozen shoulder. Correlation analyses assessed associations between pain-related beliefs and arm function. Regression analysis calculated the explained variance in arm function by pain-related beliefs.

RESULTS

Pain-related fear, pain catastrophizing and pain self-efficacy were significantly associated with arm function (r = 0.51; r = 0.45 and r = -0.69, all p < .0001, respectively). Thirty-one percent of variance in arm function was explained by control variables, with pain intensity being the only significant one. After adding TSK-11, PCS and PSEQ scores to the model, 26% extra variance in arm function was explained, with significant contributions of pain intensity, pain-related fear and pain self-efficacy (R²= 0.57).

CONCLUSIONS

Attention should be paid towards the negative effect of pain-related fear on outcomes in frozen shoulder and towards building one's pain self-efficacy given its protective value in pain management.

Discriminant validity of 3D joint kinematics and centre of mass displacement measured by inertial sensor technology during the unipodal stance task

Background

The unipodal stance task is a clinical task that quantifies postural stability and alignment of the lower limb joints, while weight bearing on one leg. As persons with knee osteoarthritis (KOA) have poor postural and knee joint stability, objective assessment of this task might be useful.

Objective

To investigate the discriminant validity of three-dimensional joint kinematics and centre of mass displacement (COM) between healthy controls and persons with knee KOA, during unipodal stance using inertial sensors. Additionally, the reliability, agreement and construct validity are assessed to determine the reproducibility and accuracy of the discriminating parameters.

Methods

Twenty healthy controls and 19 persons with unilateral severe KOA were included. Five repetitions of the unipodal stance task were simultaneously recorded by an inertial sensor system and a camera-based system (gold standard). Statistical significant differences in kinematic waveforms between healthy controls and persons with severe knee KOA were determined using one-dimensional statistical parametric mapping (SPM1D).

Results

Persons with severe knee KOA had more lateral trunk lean towards the contralateral leg, more hip flexion throughout the performance of the unipodal stance task, more pelvic obliquity and COM displacement towards the contralateral side. However, for the latter two parameters the minimum detectable change was greater than the difference between healthy controls and persons with severe knee KOA. The construct validity was good (coefficient of multiple correlation 0.75, 0.83 respectively) and the root mean squared error (RMSE) was low (RMSE <1.5°) for the discriminant parameters.

Conclusion

Inertial sensor based movement analysis can discriminate between healthy controls and persons with severe knee KOA for lateral trunk lean and hip flexion, but unfortunately not for the knee angles. Further research is required to improve the reproducibility and accuracy of the inertial sensor measurements before they can be used to assess differences in tasks with a small range of motion.

Diagnostic accuracy of saline contrast sonohysterography in detecting endometrial polyps in women with postmenopausal bleeding: systematic review and meta-analysis

OBJECTIVE

In women with postmenopausal bleeding, endometrial polyps are a frequent finding and the risk of a focal (pre)malignancy in a polyp is up to 6%. Because of this reported risk, the detection of polyps in these women, preferably by a minimally invasive method, is important. The aim of this systematic review was to assess the accuracy of saline contrast sonohysterography (SCSH) for diagnosis of endometrial polyps in women with postmenopausal bleeding.

METHODS

In August 2018, an electronic search was performed of MEDLINE, EMBASE and Web of Science databases to identify all diagnostic studies in which SCSH was used to detect endometrial polyps in postmenopausal women. Studies were included if SCSH was performed to detect endometrial polyps in women with postmenopausal bleeding and if detection of a polyp on hysteroscopy or diagnosis on histopathology was used as a reference standard. Two reviewers assessed methodological quality using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool. Two separate analyses were performed for each reference standard. Pooled sensitivity and specificity were calculated using the hierarchical summary receiver-operating characteristics (HSROC) model and HSROC curves were plotted.

RESULTS

After selection and quality assessment, five studies were included. Using 'polyps diagnosed with histopathology' as the reference standard, the pooled sensitivity of SCSH was 86.5% (95% CI, 63.6-100%) and the pooled specificity was 91.1% (95% CI, 63.2-100%). Using 'polyps seen on hysteroscopy' as the reference standard, the pooled sensitivity of SCSH was 85.1% (95% CI, 66.9-100%) and the pooled specificity was 84.5% (95% CI, 68.1-100%). Excluding the one study that included women in whom the SCSH examination was reported to be suboptimal, the pooled sensitivity increased to 90.7% (95% CI, 72.8-100%) using hysteroscopy as the reference standard. The sensitivity of hysteroscopy to detect polyps, as reported in two studies, was 81-98%.

CONCLUSIONS

Provided that the SCSH examination is of optimal quality, it can be considered as a method to stratify women with postmenopausal bleeding for further diagnostic workup and treatment with hysteroscopy. In women without suspicion of a polypoid lesion on SCSH, and with a benign endometrial sample, expectant management should be considered. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Mobile assessment of the lower limb kinematics in healthy persons and in persons with degenerative knee disorders: A systematic review

Inertial sensor systems are increasingly used in the assessment of persons with knee osteoarthritis (KOA) and total knee replacement (TKR). This systematic review aims to (1) investigate the application of inertial sensor systems and kinematics derived from these systems, and (2) assess if current assessment protocols consist of tasks which are, according to the International Classification of Functioning, Disability and Health (ICF) for KOA, relevant for persons with KOA and TKR. A search was conducted in six electronic databases (ACM, CINAHL, EMBASE, IEEE, PubMed, Web of Science) to include papers assessing the knee and one or more adjacent joints by means of inertial sensors in healthy persons or persons with KOA or TKR. Two reviewers checked the methodological quality. Twenty-three papers were included: 18 in healthy persons and five in persons with KOA or TKR. In healthy persons, 11 tasks were related to metrics of the ICF-function and ICF-activity level. In persons with KOA, only walking was assessed. Apart from walking, four additional tasks were related to the ICF-function and ICF-activity level in persons with TKR. In healthy persons, joints located proximally and distally to the knee were assessed, while in persons with KOA and TKR, only the knee and ankle were assessed. This is a shortcoming since hip and trunk motion potentially contain clinically relevant information, in terms of identifying (mal)adaptive compensatory movement strategies. Additionally, physically more demanding tasks should be evaluated as these might be superior in detecting compensatory movement strategies. Former considerations warrant attention in future research.

Capacity of endometrial thickness measurement to diagnose endometrial carcinoma in asymptomatic postmenopausal women: a systematic review and meta-analysis

OBJECTIVES

Measurement of endometrial thickness is an important tool in the assessment of women with postmenopausal bleeding, but the role of endometrial thickness measurement by ultrasound in asymptomatic women is unclear. The aims of this study were to determine: (1) the normal endometrial thickness measured by ultrasonography, (2) the prevalence of serious endometrial pathology and (3) the sensitivity and specificity of endometrial thickness measurement by transvaginal ultrasonography (TVS) for diagnosing premalignant and malignant endometrial disease in asymptomatic postmenopausal women.

METHODS

A MEDLINE and EMBASE search (from inception to January 2011) was performed. Articles reporting on endometrial thickness measurement in the diagnosis of endometrial carcinoma and atypical hyperplasia in asymptomatic postmenopausal women not using hormone replacement therapy (HRT) were selected. Endometrial thickness and the prevalence of endometrial (pre)malignancies were recorded. If possible, 2 × 2 tables were extracted.

RESULTS

Thirty-two studies reporting on 11100 women were included. The estimated mean endometrial thickness was 2.9 mm (95% CI, 2.6-3.3 mm). The pooled estimated prevalences of endometrial carcinoma and atypical endometrial hyperplasia were 0.62% (95% CI, 0.42-0.82%) and 0.59% (95% CI, 0.22-0.96%), respectively. Summary estimates for sensitivity and specificity of TVS endometrial thickness measurement in the prediction of endometrial carcinoma were 0.83 (95% CI, 0.19-1.00) and 0.72 (95% CI, 0.23-0.95) for a 5-mm cut-off and 0.33 (95% CI, 0.04-0.85) and 0.94 (95% CI, 0.92-0.96) for a 6-mm cut-off.

CONCLUSIONS

The results from this systematic review do not justify the use of endometrial thickness as a screening test for endometrial carcinoma and atypical endometrial hyperplasia in asymptomatic postmenopausal women not using HRT.

Diagnostic evaluation of the endometrium in postmenopausal bleeding: an evidence-based approach

Postmenopausal bleeding (PMB) is a common complaint in general gynecological practice. Women with PMB have around a 10% chance of having endometrial carcinoma and therefore PMB always needs further evaluation. This article summarizes the reviews on the subject and provides an overview of the use of diagnostic tools in patients with PMB. Four types of diagnostic test are described: sonographic measurement of endometrial thickness, endometrial sampling, hysteroscopy and saline infusion sonography. All four have been independently shown to be accurate in excluding endometrial cancer. However, neither in systematic reviews nor in international guidelines is consensus found regarding the sequence in which these methods should be employed in women with PMB. For measurement of endometrial thickness in symptomatic women, a cut-off value of 3mm is recommended, but the cost-effectiveness of this strategy has yet to be shown. Research should now focus on the incorporation of individual patient characteristics and pre-test probabilities for cancer in algorithms for the investigation of PMB, and the most cost-effective sequenced combination of the four types of test.

Diagnostic strategies for postmenopausal bleeding

Postmenopausal bleeding (PMB) is a common clinical problem. Patients with PMB have 10%-15% chance of having endometrial carcinoma and therefore the diagnostic workup is aimed at excluding malignancy. Patient characteristics can alter the probability of having endometrial carcinoma in patients with PMB; in certain groups of patients the incidence has been reported to be as high as 29%. Transvaginal sonography (TVS) is used as a first step in the diagnostic workup, but different authors have come to different conclusions assessing the accuracy of TVS for excluding endometrial carcinoma. Diagnostic procedures obtaining material for histological assessment (e.g., dilatation and curettage, hysteroscopy, and endometrial biopsy) can be more accurate but are also more invasive. The best diagnostic strategy for diagnosing endometrial carcinoma in patients with PMB still remains controversial. Future research should be focussed on achieving a higher accuracy of different diagnostic strategies.

Patients' preferences in the evaluation of postmenopausal bleeding

OBJECTIVE

To assess patients' preferences for diagnostic management of postmenopausal bleeding (PMB).

DESIGN

A structured interview.

SETTING

A teaching hospital with office hysteroscopy facilities.

POPULATION

Thirty-nine women with PMB and with a completed work-up including an office hysteroscopy.

METHODS

A structured interview was taken from 39 women who had had an office hysteroscopy in the diagnostic work-up for PMB. Women were informed about the probability of endometrial carcinoma versus benign disease and about advantages and disadvantages of different diagnostic strategies, i.e. expectant management after ultrasound or complete diagnostic work-up, including invasive procedures.

MAIN OUTCOME MEASURES

Women were informed about the probability of endometrial carcinoma versus benign disease and about advantages and disadvantages of different diagnostic strategies, i.e., expectant management after ultrasound or complete diagnostic work-up including invasive procedures. Women were asked to make a trade-off between different options.

RESULTS

Most women wanted to be 100% certain that carcinoma could be ruled out. Only 5% of the women were willing to accept more than 5% risk of false reassurance. If the risk of recurrent bleeding due to benign disease exceeded 25%, the majority of women would prefer immediate diagnosis and treatment of benign lesions.

CONCLUSION

Women with PMB are prepared to undergo hysteroscopy to rule out any risk on cancer. This finding implicates that the measurement of endometrial thickness with transvaginal ultrasound as a first-line test in the assessment of PMB should be reconsidered.

3-methylthiopropionaldehyde as precursor of dimethyl trisulfide in aged beers

Hop S-methylcysteine sulfoxide has previously been postulated as the precursor of dimethyl trisulfide (DMTS) in beers. The present data point to 3-methylthiopropionaldehyde, the Strecker aldehyde issued from methionine, as another potential precursor in aged beers. Spiking either fresh beer or wort before boiling leads in all cases to higher levels of DMTS after storage. Moreover, special malts with a high level of 3-methylthiopropionaldehyde also favor polysulfide synthesis. A higher pH should increase this onion-like off-flavor, whereas a low pH is unfortunately known to enhance the cardboard flavor of aged beers. 3-methylthiopropanol, issued from yeast reducing activity, can be considered as an additional DMTS source during aging.

[The ear thermometer; not a good replacement for the rectal thermometer]

OBJECTIVE

To compare the measurements of body temperature with the tympanic infrared thermometer and the digital rectal thermometer.

DESIGN

Prospective, comparative.

SETTING

Beatrix Hospital, Gorinchem, the Netherlands.

PATIENTS AND METHODS

A total of 2057 almost simultaneous measurements of rectal and tympanic temperature were performed in 164 patients in 9 different wards.

RESULTS

The mean difference between the two methods was 0.45 degree C with a standard deviation of 0.57 degree C. The tympanic temperature was lower than the rectal temperature. The differences ranged from -1.5 to 3.6 degrees C. The correlation coefficient was 0.69. If a rectal temperature > 37.8 degrees C was applied as the criterion of fever, the diagnosis was not made in 175/291 measuring moments (60%) with the tympanic thermometer. If a tympanic temperature > 37.8 degrees C was applied as the criterion of fever, the rectal thermometer failed to show fever in 16/132 measuring moments (12%).

CONCLUSION

The low sensitivity of the tympanic measurement to establish fever renders the tympanic infrared thermometer unsuitable for use as a fever thermometer.

Domains of retinoid signalling and neurectodermal expression of zebrafish otx1 and goosecoid are mutually exclusive

Retinoid signalling plays an important role in embryonic pattern formation. Excess of retinoic acid during gastrulation results in axial defects in vertebrate embryos, suggesting that retinoids are involved in early anteroposterior patterning. To study retinoid signalling in zebrafish embryos, we developed a novel method to detect endogenous retinoids in situ in embryos, using a fusion protein of the ligand inducible transactivation domain of a retinoic acid receptor and a heterologous DNA binding domain. Using this method, we show that retinoid signalling is localized in zebrafish embryos in the region of the embryonic shield, and towards the end of gastrulation in a posterior dorsal domain. To investigate the relationships between the spatial distribution of retinoid signalling and the regulation of retinoid target genes, we studied the downregulation by retinoic acid of two genes expressed in anterior regions of the embryo, goosecoid and otx1. These experiments show that expression of both genes is strongly downregulated in the anterior neurectoderm of zebrafish embryos treated with retinoic acid, whereas mesendodermal expression is only mildly affected. Interestingly, a significant downregulation of goosecoid expression by retinoic acid was observed only during midgastrulation but not in earlier stages. In agreement with these results, spatial expression of goosecoid and otx1 does not overlap with the region of retinoid signalling in the late gastrula. Our data support the hypothesis that a localized retinoid signal is involved in axial patterning during early development, at least in part through the repression of anterior genes in posterior regions of the embryo. Furthermore, our data suggest that the action of retinoids is spatially as well as temporally regulated in the developing embryo.

Defect in potentiation of adenylyl cyclase correlates with bronchial hyperreactivity

BACKGROUND

Adenylyl cyclase is a transmembrane signaling system involved in the inhibition of cellular responses. Recently, we showed that the activity of adenylyl cyclase may be potentiated by stimuli that induce an increase of cellular responses but that do not activate adenylyl cyclase. This is probably an important physiologic feedback mechanism that prevents cells from becoming "overstimulated."

OBJECTIVE

Because increased cellular activities are frequently observed in persons with asthma, we hypothesized that a defect in potentiation of adenylyl cyclase might be involved.

METHODS

Potentiation of isoprenaline-induced adenosine cyclic monophosphate (cAMP) production with the mitogen phytohemagglutin (PHA; 45 micrograms/ml) or the calcium ionophore A23187 (1 mumol/L) was studied in peripheral blood mononuclear cells taken from patients with asthma (n = 8) and healthy control subjects (n = 11).

RESULTS

Isoprenaline-induced cAMP production was potentiated significantly in the healthy control subjects (PHA, 110% +/- 15%; A23187, 92% +/- 25%). In contrast, potentiation was not seen with PHA or A23187 in the total group of patients with asthma. However, some patients showed weak potentiation, whereas in others PHA decreased isoprenaline-induced cAMP production. Moreover, the effect of PHA on isoprenaline-induced cAMP production correlated significantly with the degree of bronchial hyperreactivity in patients with asthma (r = 0.96; p = 0.0001).

CONCLUSIONS

The observed defect in signal transduction could play an important part in bronchial hyperresponsiveness.

Production of diacylglycerol and arachidonic acid in peripheral blood mononuclear cells from patients with asthma and healthy controls

BACKGROUND

Enhanced activities of peripheral blood cells are a common characteristic of patients with asthma.

OBJECTIVE

Here we tested whether this could be due to a dysfunction in one or more signal transduction systems.

METHODS

The production of 1,2-diacylglycerol (1,2-DAG) and arachidonic acid was compared in mononuclear blood cells from patients with asthma (n = 10) and healthy controls (n = 12).

RESULTS

Using three different stimuli (concanavalin A, aluminium fluoride or the calcium ionophore A23187) no difference in the production of both 1,2-DAG and arachidonic acid could be found between patients and controls before allergen challenge. Concanavalin A-induced 1,2-DAG production could be inhibited completely in the presence of isoprenaline; concanavalin A-induced arachidonic acid production, partially. The inhibitory effect of adenylate cyclase activation on the production of 1,2-DAG and arachidonic acid was identical in patients and controls. Following allergen challenge, there was a tendency to an increased production of 1,2-DAG and arachidonic acid in controls, whereas in patients there was a tendency to a decreased production.

CONCLUSIONS

Enhanced cellular activities found in patients with asthma are not caused by an intrinsic dysfunction in production of 1,2-DAG and arachidonic acid.

Overexpression of a cellular retinoic acid binding protein (xCRABP) causes anteroposterior defects in developing Xenopus embryos

We have isolated the first Xenopus laevis cDNA coding for a cellular retinoic acid binding protein (xCRABP). xCRABP contains a single open reading frame, coding for an approximately 15 × 10(3) M(r) protein. Northern blot analysis shows that this cDNA hybridizes to a mRNA that is expressed both maternally and zygotically and which already reaches maximal expression during gastrulation (much earlier than previously described CRABP genes from other species). In situ hybridisation showed that at the onset of gastrulation, xCRABP mRNA is localised at the dorsal side of the embryo, in the ectoderm and in invaginating mesoderm. xCRABP expression then rapidly resolves into two domains; a neural domain, which becomes localised in the anterior hindbrain, and a posterior domain in neuroectoderm and mesoderm. These two domains were already evident by the mid-gastrula stage. We investigated the function of xCRABP by injecting fertilized eggs with an excess of sense xCRABP mRNA and examined the effects on development. We observed embryos with clear antero-posterior defects, many of which resembled the effects of treating Xenopus gastrulae with all-trans retinoic acid. Notably, the heart was deleted, anterior brain structures and the tail were reduced, and segmentation of the hindbrain was inhibited. The effects of injecting xCRABP transcripts are compatible with the idea that xCRABP overexpression modulates the action of an endogenous retinoid, thereby regulating the expression of retinoid target genes, such as Hox genes. In support of this, we showed that the expression of two Xenopus Hoxb genes, Hoxb-9 and Hoxb-4, is strongly enhanced by xCRABP over-expression. These results suggest that xCRABP expression may help to specify the anteroposterior axis during the early development of Xenopus laevis.

Potentiation of adenylyl cyclase in human peripheral blood mononuclear cells by cell-activating stimuli

The isoprenaline-induced production of cAMP in human peripheral blood mononuclear cells (PBMC) was potentiated significantly by incubating PBMC with isoprenaline in the presence of phytohaemagglutinin (PHA), Concanavalin A (Con A) or A23187. This potentiation, that proved to be dependent on the concentration of PHA, Con A or A23187, increased the maximal response but did not cause a change in the potency of isoprenaline. Potentiation could not be induced by the phorbol ester phorbol-myristate acetate, suggesting that protein kinase C-dependent pathways are not likely to be involved in potentiation of adenylyl cyclase. Potentiation could be inhibited by chelating extracellular Ca2+ with EGTA and also by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamine, an inhibitor of calmodulin. Potentiation could not be induced by preincubation of PBMC with PHA, suggesting that transient biochemical changes are involved. It was concluded from these results that potentiation in PBMC probably involves the activation of Ca2+/calmodulin-dependent adenylyl cyclase subtypes. Potentiation of the adenylyl cyclase activity could be an important physiological mechanism in vivo preventing cells from becoming "over stimulated".

Desensitization of the adenylyl cyclase system in peripheral blood mononuclear cells from patients with asthma three hours after allergen challenge

BACKGROUND

Bronchial hyperreactivity is a common characteristic of patients with asthma and is often associated with enhanced activities of peripheral blood cells. Signal transduction systems are important in regulating cellular activities and can be modified by allergen challenge.

METHODS

Patients with allergic asthma (n = 15) were challenged with house dust mite allergen, resulting in an asthmatic response. Adenylyl cyclase activity was measured in membranes from peripheral blood mononuclear cells before, 3 hours after, and 24 hours after challenge.

RESULTS

Allergen challenge proved to have opposite effects in two distinct subgroups of patients. In 10 patients (group I) a heterologous desensitization of the adenylyl cyclase system was observed after challenge, whereas in five patients (group II) an increase in adenylyl cyclase activity was found. Adenylyl cyclase activity before allergen challenge in group II was significantly lower than in group I and comparable to cyclase activity found in group I after allergen challenge. This suggests that in these five patients the adenylyl cyclase system was already desensitized before the start of the study, possibly as a result of natural allergen exposure. Heterologous desensitization in group I was found within 3 hours after allergen challenge, that is before the onset of the late bronchoconstrictive reaction.

CONCLUSIONS

Because adenylyl cyclase is important in the regulation of cytokine production by mononuclear cells, alteration of cytokine production induced by desensitization of adenylyl cyclase could therefore play a role in the development of the late bronchoconstrictive reaction.

Lack of coupling of muscarinic receptors to phosphoinositide metabolism and adenylyl cyclase in human lymphocytes and polymorphonuclear leukocytes: studies in healthy subjects and allergic asthmatic patients

A change in muscarinic receptor-induced phosphoinositide (PI) metabolism or inhibition of adenylyl cyclase activity could play a role in cholinergic hyperresponsiveness in patients with asthma. In the present study, we considered the possibility of using peripheral blood lymphocytes or polymorphonuclear leukocytes (PMN) as easily accessible models to investigate this hypothesis. Previous studies have indicated the presence of muscarinic binding sites on these cells; however, their transduction mechanisms are still unclear. We found that neither lymphocytes nor PMN from healthy donors, nor lymphocytes from allergic asthmatic patients accumulated inositol phosphates after stimulation with methacholine, whereas positive responses were found for phytohemagglutinin (PHA) in the lymphocytes and for formyl-methionyl-leucyl-phenyl-alanine in the PMN. Normal basal and PHA-stimulated inositol phosphates levels were found in the lymphocytes of the patients. Both levels were significantly enhanced after allergen challenge, indicating that activation of PI metabolism could play a role in the immune response of these cells. Since methacholine was also unable to inhibit adenylyl cyclase activity in both lymphocytes and PMN, we reevaluated the presence of muscarinic binding sites on these cells. Radioligand binding studies with the hydrophilic ligand [3H]-N-methyl-scopolamine surprisingly showed only a very small population of high affinity binding sites on lymphocytes (Bmax 57-127 sites/cell; Kd 45-133 pM), while no high affinity sites could be detected on PMN. The results indicate that leukocytes are not a suitable model to investigate the muscarinic receptor function in relation to bronchial asthma.

Monoclonal antibodies for immunohistochemical labeling of immunocompetent cells in frozen sections of rhesus monkey tissues

Twenty-eight anti-human and two rhesus specific monoclonal antibodies (MAbs) were evaluated for immunohistochemical peroxidase staining reactivity in rhesus monkeys lymph nodes, thymus, liver, and skin allografts. Reactivity with the following antigens was assessed: MHC class I, II-DR, -DQ, and -DP antigens; leukocyte markers CD1, CD2, CD3, CD4, CD8, CD14, CD16, CD25, CD57; a proliferation associated nuclear antigen; interferon-gamma and tumor necrosis factor-alpha. Twenty-three MAbs proved to be suitable for immunohistochemical staining on frozen sections.

Characterization of a maternal type VI collagen in Xenopus embryos suggests a role for collagen in gastrulation

We characterized a novel extracellular matrix element that is present in the earliest developmental stages of Xenopus laevis, and is recognized by an mAb 3D7. Based on amino acid composition, breakdown patterns by bacterial collagenases, and the molecular weights of the components of the antigen (240, 200, and 140 kD), we found it very similar to mammalian collagen type VI. The antigen is evenly distributed in unfertilized eggs. Shortly after fertilization, it becomes localized intracellularly in the periphery of the cleaving embryo as well as in the extracellular spaces. During gastrulation, the antigen was localized in the cells lining the blastopore and in the extracellular space between the two cell layers, in the presumptive archenteron. When Fab elements of the 3D7 antibody were added to the culture medium, gastrulation was blocked, suggesting a role for the antigen in gastrulation movements.

Muscarinic receptors in human airway smooth muscle are coupled to phosphoinositide metabolism

In the present study we investigated whether muscarinic receptors in human airway smooth muscle are coupled to phosphoinositide metabolism as a possible transduction mechanism of contraction. Using isolated bronchial smooth muscle preparations, we found that the muscarinic agonist methacholine caused a time- and concentration-dependent accumulation of inositol phosphates in the presence of lithium, an effect which could be inhibited by atropine. Apart from its physiological significance, this finding may have great relevance for the biochemical investigation of cholinergic hyperresponsiveness in the airways of asthmatic patients.

Role of phosphoinositide metabolism in functional antagonism of airway smooth muscle contraction by beta-adrenoceptor agonists

Histamine and the muscarinic agonists, methacholine, oxotremorine, and McN-A-343, were used to contract guinea-pig tracheal smooth muscle preparations. Cumulative dose-relaxation curves with isoprenaline were performed subsequently. In addition, the concentration-dependent induction of phosphoinositide metabolism by the contractile agonists was measured in bovine tracheal smooth muscle. All agonists were found to induce a decrease of the apparent affinity of isoprenaline and a loss of relaxation, depending on the concentration and type of contractile agonist used. The differential effects of the contractile agonists, especially at higher and supramaximal concentrations, on these beta-adrenergic parameters could be explained by differences in phosphoinositide metabolism.

Evidence for a direct relationship between phosphoinositide metabolism and airway smooth muscle contraction induced by muscarinic agonists

The relationship between bovine tracheal muscle contraction and phosphoinositide metabolism was studied with the muscarinic agonists, methacholine, oxotremorine, and McN-A-343. Analysis of the dose-response curves for contraction and inositol phosphates accumulation with these agonists demonstrated a direct relationship between the two parameters, with a considerable reserve of inositol phosphate production for the full contractile agonists, methacholine and oxotremorine, and no reserve for the partial agonist, McN-A-343.

The beta-adrenergic system of non-allergic patients with chronic airflow obstruction and early morning dyspnoea

Lymphocyte beta-adrenergic receptor function and urinary excretion of catecholamines were measured in eight non-allergic patients with partially reversible chronic airflow obstruction (CAO) and early morning dyspnoea (EMD), and in eight matched healthy control subjects. In order to establish a possible relationship between the early morning dyspnoea and a reduced beta-adrenergic activity, these parameters were measured during the "morning dip" in FEV1 and in the afternoon, when lung function is maximal. No differences were observed for lymphocyte beta-adrenergic receptor characteristics (beta-receptor number, Kd, for 3H-dihydroalprenolol, and cAMP response to isoproterenol) between patients and controls, when determined at 8 AM or at 4 PM. Nor was there a significant circadian variation in these parameters present in both groups. By contrast, the patients showed a significantly reduced urinary excretion of epinephrine and norepinephrine, as measured in four-hourly urine portions collected between 8 and 12 AM and between 4 and 8 PM, respectively. In addition, the urinary excretion of epinephrine showed a significant circadian variation in the patients, which was correlated with the FEV1 (% predicted). Such a relationship was not found for norepinephrine. The results suggest that a (generalized) dysfunction of the beta-adrenergic receptor is not involved in the pathogenesis of CAO or EMD. However, reduced beta-adrenergic receptor stimulation due to decreased levels of catecholamines may contribute to the observed (variation in) airflow obstruction of the patients.

Regulation of the beta-receptor-adenylate cyclase system in lymphocytes of allergic patients with asthma: possible role for protein kinase C in allergen-induced nonspecific refractoriness of adenylate cyclase

Allergen challenge of allergic patients with asthma caused various changes in the beta-receptor-adenylate cyclase system of lymphocyte membranes from these patients. These changes included uncoupling and down regulation of beta-adrenergic receptors and nonspecific refractoriness of adenylate cyclase, as demonstrated by reduced responses to isoproterenol (beta 2), histamine (H2), 5'-guanylylimidodiphosphate, and sodium fluoride. Since these changes could be due to desensitization by enhanced plasma levels of catecholamines and/or histamine during the allergic response, we explored the effects of these agonists on the beta-receptor-adenylate cyclase system in vitro with normal lymphocytes. In addition, we assessed the effect of the tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate (PMA), on this system, since phorbol esters have been demonstrated to modulate several receptor systems, presumably via activation of protein kinase C. That both the agonists and PMA may cause refractoriness of lymphocyte adenylate cyclase was demonstrated, but, however, by apparently different mechanisms. The agonists isoproterenol and histamine induced only a specific desensitization of the homologous responses, whereas PMA-induced refractoriness was nonspecific in nature. Radioligand-binding studies demonstrated that both uncoupling and down regulation contributed to the isoproterenol-induced beta-adrenergic hyporesponsiveness, whereas beta-adrenergic receptor uncoupling but not beta-adrenergic receptor down regulation was involved in PMA-induced desensitization. Histamine had no effect on the beta-adrenergic system at all. The data suggest that the agonist-induced changes in the adenylate cyclase system are specifically located at the receptors, whereas PMA-induced refractoriness can be explained by alterations distal to the receptors, presumably at the stimulatory guanine nucleotide regulatory protein. Thus, enhanced levels of catecholamines or histamine could be involved in the development of receptor-specific changes in the lymphocyte adenylate cyclase system of allergic patients with asthma. However, they are unlikely to cause the nonspecific changes distal to the receptors. The latter changes could be induced by physiologic activation of protein kinase C during the allergic response by a still unknown stimulus, possibly via the receptor-mediated turnover of phosphatidylinositol 4,5-diphosphate.

Phorbol 12-myristate 13-acetate induces beta-adrenergic receptor uncoupling and non-specific desensitization of adenylate cyclase in human mononuclear leukocytes

Tumour-promoting phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate beta-adrenergic receptor responses in various cell types, presumably by the activation of protein kinase C. In the present investigation we assessed the effect of PMA on the beta-adrenergic receptor-adenylate cyclase system of human mononuclear leukocytes (MNL). It was found that incubation of MNL with PMA resulted in a time- and concentration-dependent desensitization of isoproterenol-induced adenylate cyclase activity. However, the effect of PMA was not restricted to the beta-adrenergic receptor system, since basal adenylate cyclase activity and histamine-, prostaglandin E1-, 5'-guanylylimidodiphosphate (GppNHp)-, and NaF-stimulated values were also reduced. By contrast, no effect was found on the forskolin-induced adenylate cyclase activity. The inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate had no effect on adenylate cyclase at all, suggesting that the observed PMA effect was specifically mediated by activation of protein kinase C. The reduced beta-adrenergic response induced by PMA was not associated with a reduced beta-adrenergic receptor number, indicating uncoupling of this receptor from adenylate cyclase. Isoproterenol competition curves for 3H-dihydroalprenolol binding to membranes from untreated and PMA-treated cells demonstrated that the uncoupling was due to a reduced ability of the agonist to promote formation of the guanine nucleotide-sensitive high affinity state of the receptor. The results indicate that PMA may cause desensitization of catecholamine-responsive adenylate cyclase in MNL, and that the major locus of alteration is the guanine nucleotide regulatory protein.

Specific immunological modulation of lymphocyte adenylate cyclase in asthmatic patients after allergenic bronchial provocation

Adenylate cyclase responses to isoproterenol, histamine, 5'-guanylylimidodiphosphate (GppNHp) and NaF were measured in lymphocyte membranes of allergic asthmatic patients and healthy control subjects, just before and 24 h after inhalation challenge with house dust mite allergen or histamine. In the nonacute phase before the challenges, the adenylate cyclase responses in the cell membranes of the patients were not significantly different from those in membranes of the control subjects. House dust mite challenge caused a significant decrease of all adenylate cyclase responses in the cell membranes of the patients by about 40-50%. By contrast, histamine provocation of the patients had no effect on these parameters, nor was there any effect of both challenges on the adenylate cyclase activity of the control membranes. The results indicate that allergen-induced asthmatic reactions may cause nonspecific refractoriness of lymphocyte adenylate cyclase. Since histamine-induced bronchial obstruction had no effect in the patients, it appears that the adenylate cyclase response is specifically modulated by the allergic process.

Reduced adenylate cyclase responsiveness to histamine in lymphocyte membranes of allergic asthmatic patients after allergen challenge

The adenylate cyclase response to histamine was measured in lymphocyte membranes of allergic asthmatic patients and healthy control subjects, just before and 24 h after inhalation challenge with house dust mite allergen. In the non-acute phase before allergen challenge, the histamine response in the membranes of the patients was not significantly different from that in membranes of the control subjects. After the house dust mite-induced asthmatic reaction, however, the adenylate cyclase response to histamine in the membranes of the patients was significantly reduced by 47%, whereas allergen inhalation had no effect on the histamine response of the control membranes. The results suggest that allergic asthmatic reactions may cause reduced lymphocyte adenylate cyclase responsiveness to histamine. A similar mechanism in the airways might contribute to allergen-induced enhanced airway reactivity to histamine.