Understanding the association between adolescent marijuana use and later serious drug use: gateway effect or developmental trajectory?

Because marijuana use often precedes the use of other psychoactive substances, it has been characterized as a gateway to these other substances. The present study used data from both monozygotic (MZ) and dizygotic (DZ) twin pairs drawn from the National Longitudinal Study of Adolescent Youth (Add Health) to examine the "gateway effect" role of earlier marijuana on later hard drug use. Difference score analyses reveal that within-pair differences in earlier marijuana use, controlling for differences in earlier hard drug use, and peer marijuana use predicted later within-pair hard drug use differences for DZ twin pairs. In contrast, earlier differences in marijuana use among MZ twin pairs did not predict later hard drug use differences. Rather than supporting the interpretation that earlier marijuana use "triggers" later hard drug use, these results suggest that the longitudinal pattern of drug use that has been interpreted as the "gateway effect" might be better conceptualized as a genetically influenced developmental trajectory.     

Depression and dementia: Cause,consequence or coincidence?

The relationship between depression and dementia is complex and still not well understood. A number of different views exist regarding how the two conditions are linked as well as the underlying neurobiological mechanisms at work.     

Is there an association between the use of heeled footwear and schizophrenia?

Existing etiological and pathogenetical theories of schizophrenia have only been able to find support in some epidemiological, clinical, and pathophysiological facts. A selective literature review and synthesis is used to present a hypothesis that finds support in all facts and is contradicted by none. Heeled footwear began to be used more than a 1000 years ago, and led to the occurrence of the first cases of schizophrenia. Industrialization of shoe production increased schizophrenia prevalence. Mechanization of the production started in Massachusetts, spread from there to England and Germany, and then to the rest of Western Europe. A remarkable increase in schizophrenia prevalence followed the same pattern. In Baden in Germany the increasing stream of young patients more or less hastily progrediating to a severe state of cognitive impairment made it possible for Kraepelin to delineate dementia praecox as a nosological entity. The patients continued to use heeled shoes after they were admitted to the hospitals and the disease progrediated. High rates of schizophrenia are found among first-generation immigrants from regions with a warmer climate to regions with a colder climate, where the use of shoes is more common. Still higher rates among second-generation immigrants are caused by the use of shoes during the onset of walking at an age of about 11-12 months. Other findings point to the importance of this in the later development of schizophrenia. A child born in January-March begins to walk in December-March, when it's cold outside and the chances of going barefoot are smaller. They are also smaller in urban settings. During walking synchronised stimuli from mechanoreceptors in the lower extremities increase activity in cerebello-thalamo-cortico-cerebellar loops through their action on NMDA-receptors. Using heeled shoes leads to weaker stimulation of the loops. Reduced cortical activity changes dopaminergic function which involves the basal ganglia-thalamo-cortical-nigro-basal ganglia loops. Bicycle riding reduces depression in schizophrenia due to stronger stimulation by improved lengthening contractions of the triceps surae muscles. Electrode stimulation of cerebellar loops normally stimulated by mechanoreceptors in the lower extremities could improve functioning in schizophrenia. Cross-sectional prevalence studies of the association between the use of heeled footwear and schizophrenia should be made in immigrants from regions with a warmer climate or in groups of people who began to wear shoes at different ages.     

Is there an association between postural balance and pulmonary function in adults with asthma?

OBJECTIVE:

Asthma may cause systemic repercussions due to its severity and the effects of treatment. Our objective was to compare posture, balance, functional capacity, and quality of life (QOL) according to the severity of disease, as assessed by pulmonary function levels.

METHOD:

This cross-sectional study evaluated fifty individuals with asthma. We compared two groups of adult individuals who were divided according to the median of the forced expiratory volume in one second (FEV₁) as follows: group A  =  FEV₁>74% predicted; group B  =  FEV₁<74% predicted. All patients underwent the following tests: spirometry, whole-body plethysmography, diffusing capacity for carbon monoxide (DLco), respiratory muscle strength, posture assessment, stabilometry, six-minute walking distance (6MWD), and QOL.

RESULTS:

All pulmonary function variables exhibited statistically significant differences between the two groups, except for the DLco. The maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6MWD were lower in group B. The maximal mediolateral velocity and the mediolateral displacement were significantly different, while the postural changes and QOL were similar between the groups.

CONCLUSIONS:

In adult individuals with asthma, the pulmonary function is associated with balance control in the mediolateral direction but does not influence the postural changes or QOL.     

The association between family history of asthma and the prevalence of asthma among US adults: National Health and Nutrition Examination Survey, 1999–2004

PurposeTo assess the overall prevalence of asthma and the association between family history of asthma and the prevalence of asthma among US adults.MethodsWe analyzed National Health and Nutrition Examination Survey data from 1999 to 2004 for 15,008 respondents aged 20 years or older with no history of emphysema. We divided respondents into three familial risk groups (high, moderate, and average) on the basis of the number and closeness of relatives, that they reported as having asthma and then assessed the asthma prevalence in each. We also assessed associations between asthma prevalence and age, sex, race/ethnicity, income, body mass index, smoking status, household smoking exposure, and physical activity.ResultsBy our definitions, 2.3% of respondents were at high, 13.0% at moderate, and 84.7% at average familial risk for asthma. The crude prevalence of self-reported lifetime asthma was 11.5% (95% confidence interval [CI]: 10.7–12.3%) among all respondents, and 37.6% (95% CI: 30.4–45.4%), 20.4% (95% CI: 18.2–22.7%), and 9.4% (95% CI: 8.7–10.2%) among those at high, moderate, and average familial risk, respectively. Among all risk factors we looked at, family history had the strongest association with lifetime asthma prevalence, and the association remained significant after adjustments for other risk factors. Compared with average familial risk, the adjusted odds ratios for lifetime asthma were 2.4 (95% CI: 2.0–2.8) for moderate and 4.8 (95% CI: 3.5–6.7) for high familial risk.ConclusionOur findings showed that a family history of asthma is an important risk factor for asthma and that familial risk assessments can help identify people at highest risk for developing asthma. Additional research is needed to assess how health care professionals can use family history information in the early detection and management of asthma.     

The cross-talk between dendritic and regulatory T cells: good or evil?

Immune responses against pathogens require fine regulation to avoid excessive inflammation, which could be harmful to the host. Moreover, the immune system must be tolerant to nonpathogenic antigens to prevent allergy, autoimmunity, and transplant rejection. There is accumulating evidence that interactions between dendritic cells (DC) and regulatory T (Treg) cells play a crucial role in the balance between immune response and tolerance. Communications between these cells are complex, bidirectional, and mediated by soluble or cell surface molecules. The maturation status of DC, which may be influenced by different microenvironmental factors, is considered as an important checkpoint for the induction of peripheral tolerance through modifications of the activation status of T cells. Moreover, several lines of experimental evidence suggest that different subsets or the functional status of DC are also involved in the promotion of Treg cell differentiation. A better knowledge of the regulatory mechanisms of the immune response induced or inhibited by DC via their interactions with Treg cells could be relevant for the development of new, immunotherapeutic approaches.     

COVID-19 and hemolysis,elevated liver enzymes and thrombocytopenia syndrome in pregnant women - association or causation?

Pregnant women are among the high-risk population for severe coronavirus disease 2019 (COVID-19) with unfavorable peripartum outcomes and increased incidence of preterm births. Hemolysis, the elevation of liver enzymes, and low platelet count (HELLP) syndrome and severe preeclampsia are among the leading causes of maternal mortality. Evidence supports a higher odd of pre-eclampsia in women with COVID-19, given overlapping pathophysiology. Involvement of angiotensin-converting enzyme 2 receptors by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the entry to the host cells and its downregulation cause dysregulation of the renin-angiotensin-aldosterone system. The overexpression of Angiotensin II mediated via p38 Mitogen-Activated Protein Kinase pathways can cause vasoconstriction and uninhibited platelet aggregation, which may be another common link between COVID-19 and HELLP syndrome. On PubMed search from January 1, 2020, to July 30, 2022, we found 18 studies on of SARS-COV-2 infection with HELLP Syndrome. Most of these studies are case reports or series, did not perform histopathology analysis of the placenta, or measured biomarkers linked to pre-eclampsia/HELLP syndrome. Hence, the relationship between SARS-CoV-2 infection and HELLP syndrome is inconclusive in these studies. We intend to perform a mini-review of the published literature on HELLP syndrome and COVID-19 to test the hypothesis on association vs causation, and gaps in the current evidence and propose an area of future research.