Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors.

METHOD

Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change.

RESULTS

Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status.

CONCLUSIONS

We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

Evidence for distinct genetic and environmental influences on fear acquisition and extinction

BACKGROUND

Anxiety disorders are highly prevalent with an early age of onset. Understanding the aetiology of disorder emergence and recovery is important for establishing preventative measures and optimising treatment. Experimental approaches can serve as a useful model for disorder and recovery relevant processes. One such model is fear conditioning. We conducted a remote fear conditioning paradigm in monozygotic and dizygotic twins to determine the degree and extent of overlap between genetic and environmental influences on fear acquisition and extinction.

METHODS

In total, 1937 twins aged 22-25 years, including 538 complete pairs from the Twins Early Development Study took part in a fear conditioning experiment delivered remotely via the Fear Learning and Anxiety Response (FLARe) smartphone app. In the fear acquisition phase, participants were exposed to two neutral shape stimuli, one of which was repeatedly paired with a loud aversive noise, while the other was never paired with anything aversive. In the extinction phase, the shapes were repeatedly presented again, this time without the aversive noise. Outcomes were participant ratings of how much they expected the aversive noise to occur when they saw either shape, throughout each phase.

RESULTS

Twin analyses indicated a significant contribution of genetic effects to the initial acquisition and consolidation of fear, and the extinction of fear (15, 30 and 15%, respectively) with the remainder of variance due to the non-shared environment. Multivariate analyses revealed that the development of fear and fear extinction show moderate genetic overlap (genetic correlations 0.4-0.5).

CONCLUSIONS

Fear acquisition and extinction are heritable, and share some, but not all of the same genetic influences.

Examining clinical correlates, treatment outcomes and mediators in young people with comorbid obsessive-compulsive disorder and autism spectrum disorder

Despite the high comorbidity, surprisingly little is known about the clinical features, treatment prognosis, and treatment mediators for youth with Obsessive-Compulsive Disorder (OCD) and Autism Spectrum Disorder (ASD). This study, the largest to date, compared 172 young people with OCD and ASD (OCD + ASD) to 447 without ASD (OCD) on clinical characteristics, finding those with OCD + ASD were more likely to endorse poorer insight into their OCD, have greater global functional impairment, greater levels of concurrent psychopathology, higher levels of family accommodation and to be on medication. Treatment outcomes following a course of Cognitive Behaviour Therapy with or without medication were explored for a subgroup; 100 young people with OCD + ASD and 223 with OCD. Whilst both groups benefitted from treatment, the OCD + ASD group had significantly poorer treatment outcomes. Greater global functional impairment and being on medication mediated the between-group difference in outcomes. Further research and treatment refinements are needed to improve outcomes for youth with OCD + ASD.

Reciprocal links between anxiety sensitivity and obsessive-compulsive symptoms in youth: a longitudinal twin study

BACKGROUND

Anxiety sensitivity, the tendency to fear the symptoms of anxiety, is a key risk factor for the development anxiety disorders. Although obsessive-compulsive disorder was previously classified as an anxiety disorder, the prospective relationship between anxiety sensitivity and obsessive-compulsive symptoms (OCS) has been largely overlooked. Furthermore, a lack of genetically informative studies means the aetiology of the link between anxiety sensitivity and OCS remains unclear.

METHODS

Adolescent twins and siblings (N = 1,579) from the G1219 study completed self-report questionnaires two years apart assessing anxiety sensitivity, OCS, anxiety and depression. Linear regression models tested prospective associations between anxiety sensitivity and OCS, with and without adjustment for anxiety and depressive symptoms. A phenotypic cross-lagged model assessed bidirectional influences between anxiety sensitivity and OCS over time, and a genetic version of this model examined the aetiology of these associations.

RESULTS

Anxiety sensitivity was prospectively associated with changes in OCS, even after controlling for comorbid anxiety and depressive symptoms. The longitudinal relationship between anxiety sensitivity and OCS was bidirectional, and these associations were predominantly accounted for by nonshared environmental influences.

CONCLUSIONS

Our findings are consistent with the notion that anxiety sensitivity is a risk factor for OCS during adolescence, but also suggest that experiencing OCS confers risk for heightened anxiety sensitivity. The reciprocal links between OCS and anxiety sensitivity over time are likely to be largely mediated by nonshared environmental experiences, as opposed to common genes. Our findings raise the possibility that interventions aimed at ameliorating anxiety sensitivity could reduce risk for OCS, and vice versa.

Paediatric Obsessive-Compulsive Disorder and Depressive Symptoms: Clinical Correlates and CBT Treatment Outcomes

Depression frequently co-occurs with paediatric obsessive-compulsive disorder (OCD), yet the clinical correlates and impact of depression on CBT outcomes remain unclear. The prevalence and clinical correlates of depression were examined in a paediatric specialist OCD-clinic sample (N = 295; Mean = 15 [7 – 18] years, 42 % female), using both dimensional (Beck Depression Inventory-youth; n = 261) and diagnostic (Development and Wellbeing Assessment; n = 127) measures of depression. The impact of depressive symptoms and suspected disorders on post-treatment OCD severity was examined in a sub-sample who received CBT, with or without SSRI medication (N = 100). Fifty-one per-cent of patients reported moderately or extremely elevated depressive symptoms and 26 % (95 % CI: 18 – 34) met criteria for a suspected depressive disorder. Depressive symptoms and depressive disorders were associated with worse OCD symptom severity and global functioning prior to CBT. Individuals with depression were more likely to be female, have had a psychiatric inpatient admission and less likely to be attending school (ps < 0.01). OCD and depressive symptom severity significantly decreased after CBT. Depressive symptoms and depressive disorders predicted worse post-treatment OCD severity (βs = 0.19 and 0.26, ps < 0.05) but became non-significant when controlling for pre-treatment OCD severity (βs = 0.05 and 0.13, ns). Depression is common in paediatric OCD and is associated with more severe OCD and poorer functioning. However, depression severity decreases over the course of CBT for OCD and is not independently associated with worse outcomes, supporting the recommendation for treatment as usual in the presence of depressive symptoms.

Transformation obsessions in paediatric obsessive-compulsive disorder: Clinical characteristics and treatment response to cognitive behaviour therapy

BACKGROUND AND OBJECTIVES

Transformation obsessions denote an under-reported symptom of Obsessive Compulsive Disorder (OCD), characterised by an excessive fear of turning into another person/object or acquiring unwanted characteristics. Relative to other OCD symptoms, little is known about the clinical presentation of transformation obsessions. The study aims to examine the clinical correlates and treatment prognosis of transformation obsessions in a paediatric OCD sample.

METHODS

The sample consisted of 346 youths with a primary diagnosis of OCD. Patients with and without transformation obsessions were compared in terms of demographic and clinical characteristics, and CBT outcomes.

RESULTS

10% of the sample endorsed transformation obsessions. Patients with transformation obsessions were more likely to be boys, to be on augmented medication regimes, and to present with more severe obsessions at assessment. A factor analysis identified four major OCD symptom clusters, with transformation obsessions loading on a 'forbidden thoughts' factor alongside aggressive, sexual, and religious obsessions. No group differences in treatment outcomes were observed.

LIMITATIONS

Limitations include the cross-sectional and retrospective nature of the study, the representativeness of our sample, and use of concomitant medication, among others.

CONCLUSIONS

The study provides the first empirical evidence regarding phenomenological similarities and differences between paediatric OCD patients presenting with and without transformation obsessions. The findings suggest that transformation obsessions are best conceptualised as related to 'forbidden' obsessions and respond to exposure-based CBT.

Genetic and environmental influences on obsessive-compulsive behaviour across development: a longitudinal twin study

BACKGROUND

Little is known about the factors influencing the stability of obsessive-compulsive behaviour (OCB) from childhood to adolescence. The current study aimed to investigate: (1) the stability of paediatric OCB over a 12-year period; (2) the extent to which genetic and environmental factors influence stability; and (3) the extent to which these influences are stable or dynamic across development.

METHOD

The sample included 14 743 twins from a population-based study. Parental ratings of severity of OCB were collected at ages 4, 7, 9 and 16 years.

RESULTS

OCB was found to be moderately stable over time. The genetic influence on OCB at each age was moderate, with significant effects also of non-shared environment. Genetic factors exerted a substantial influence on OCB persistence, explaining 59-80% of the stability over time. The results indicated genetic continuity, whereby genetic influences at each age continue to affect the expression of OCB at subsequent ages. However, we also found evidence for genetic attenuation in that genetic influences at one age decline in their influence over time, and genetic innovation whereby new genes 'come on line' at each age. Non-shared environment influenced stability of OCB to a lesser extent and effects were largely unique to each age and displayed negligible influences on OCB at later time points.

CONCLUSIONS

OCB appears to be moderately stable across development, and stability is largely driven by genetic factors. However, the genetic effects are not entirely constant, but rather the genetic influence on OCB appears to be a developmentally dynamic process.

Proceedings from an international consensus meeting on posttransplantation diabetes mellitus: recommendations and future directions

A consensus meeting was held in Vienna on September 8-9, 2013, to discuss diagnostic and therapeutic challenges surrounding development of diabetes mellitus after transplantation. The International Expert Panel comprised 24 transplant nephrologists, surgeons, diabetologists and clinical scientists, which met with the aim to review previous guidelines in light of emerging clinical data and research. Recommendations from the consensus discussions are provided in this article. Although the meeting was kidney-centric, reflecting the expertise present, these recommendations are likely to be relevant to other solid organ transplant recipients. Our recommendations include: terminology revision from new-onset diabetes after transplantation to posttransplantation diabetes mellitus (PTDM), exclusion of transient posttransplant hyperglycemia from PTDM diagnosis, expansion of screening strategies (incorporating postprandial glucose and HbA1c) and opinion-based guidance regarding pharmacological therapy in light of recent clinical evidence. Future research in the field was discussed with the aim of establishing collaborative working groups to address unresolved questions. These recommendations are opinion-based and intended to serve as a template for planned guidelines update, based on systematic and graded literature review, on the diagnosis and management of PTDM.

[Renal denervation for resistant hypertension without general anesthesia: advantage of a MEOPA morphine protocol. Preliminary experience]

Renal denervation using the technique of radiofrequency is used only recently for the treatment of resistant hypertension. Normally, it is done under general anesthesia because the ablation point technique is painful. We suggest an alternative to general anesthesia comprising an association of morphin 0.1mg/kg IV to MEOPA (gas combining oxygen and azot protoxyd) delivered through an oxygen mask. Our series includes 12 consecutive patients treated between October 2011 and June 2013, the first five patients (group 1) have received only an hydroxizin and morphin sedation. Every five have felt the ablation painful, in two cases bearable pain (EVA<5), in three cases intense (EVA>5) pain leading to increasing doses of morphin, (total dose of 0.25mg/kg in two cases, 0.17mg in one case). For the seven following patients, a protocol including hydroxyzin, morphin and MEOPA given through a mask has been set up. Only one patient has felt a mild pain (EVA 5) leading to an increasing dose of morphin (total dose 0.17mg/kg). None of the six other patients has felt any pain during the procedure. The average dose of morphin is 0.17mg/kg in group 1, 0.11mg/kg in group 2. This is a preliminary study; if confirmed, it will allow a lot of hospitals without on-site possibilities of general anesthesia, to realize such procedures.

CONCLUSION

regarding pain, the procedure of renal ablation was well tolerated for six among seven patients receiving the association MEOPA and IV morphin. In contrast, in the five patients treated only with IV morphin, we observed a less good tolerance to pain and the need to increase the doses of IV morphin.

Effects of Lewisite on cell membrane integrity and energy metabolism in human keratinocytes and SCL II cells

Lewisite is a highly toxic arsenic compound which can cause skin damage. In the present study effects of Lewisite on cell membrane integrity and energy metabolism as well as antidotal effects of DL-2,3-dimercaptopropanesulfonate (DMPS), and meso-2,3-dimercaptosuccinic acid (m-DMSA) were investigated in a keratinocyte derived cell line (SCL II) and primary human keratinocytes (HK). Cells were incubated in Lewisite (60 microM) containing medium for 5 min. During the following 6 h lactate dehydrogenase (LDH) activity in the supernatant, intracellular ATP content, tetrazolium reduction, glucose consumption and lactate formation were measured. Glucose consumption and lactate production were decreased in both cell lines after Lewisite exposure. In SCL II cells an increase of LDH activity in the supernatant, a decrease of ATP content, and an impaired ability to reduce tetrazolium was found 3 h after Lewisite exposure. In HK cultures tetrazolium reduction was significantly decreased already after 2 h, whereas LDH increase in the supernatant and ATP content decrease occurred only at 6 h after Lewisite exposure. When DMPS or m-DMSA was added directly after Lewisite exposure to SCL II cells, glucose consumption and lactate formation were restored and LDH leakage was prevented. SCL II cells might be more prone to membrane damage whereas in keratinocytes mitochondrial impairment seems to be the predominant effect of Lewisite.

The impact of contralateral cooling on skin capillary blood cell velocity in patients with diabetes mellitus

In healthy volunteers, cooling of the contralateral hand leads to a rapid decrease in the ipsilateral capillary perfusion via a nerval reflex arc. The aim of this study was to investigate whether this reflex arc after contralateral cooling might be altered in patients with diabetes mellitus with and without peripheral neuropathy. Therefore, 12 patients with diabetic neuropathy (4 IDDM, diabetes duration 17.2 +/- 2.9 (SD) years, age 60.8 +/- 4.0 years, HbA1c 6.5 +/- 0.3%) and 12 patients with diabetes mellitus but without neuropathy (6 IDDM, diabetes duration 15.1 +/- 2.7 years, age 55.9 +/- 4.5 years, HbA1c 5.4 +/- 0.1%) were investigated by nailfold capillaroscopy. Twelve healthy volunteers (age 56.8 +/- 3.1 years, HbA1c 4.8 +/- 0.2%) served as controls. Contralateral skin capillary blood cell velocity was determined at rest and during the following 20 min after cooling of the hand (3 min at 15 degreesC). Blood pressure, heart rate and local skin temperature were examined regularly during the investigation. Resting capillary blood cell velocity did not differ between patients and controls. While contralateral cooling resulted in a decrease in capillary blood cell velocity (CBV) in controls (0.29 +/- 0.05 vs. 0.42 +/- 0.05 mm/s, p < 0.03), CBV remained unchanged or was delayed in patients. These results demonstrate that in diabetic patients nerval reflex arcs are impaired. A long-term follow-up in a larger number of patients is required to evaluate whether these findings might serve as a very early diagnostic tool for the diagnosis of developing diabetic neuropathy.

Inclusive dielectron cross sections in p + p and p + d interactions at beam energies from 1.04 to 4.88 GeV

Measurements of dielectron production in p + p and p + d collisions with beamkinetic energies from 1.04 to 4.88 GeV are presented. The differential cross section is presented as a function of invariant pair mass, transverse momentum, and rapidity. The shapes of the mass spectra and their evolution with beam energy provide information about the relative importance of the various dielectron production mechanisms in this energy regime. The p + d to p + p ratio of the dielectron yield is also presented as a function of invariant pair mass, transverse momentum, and rapidity. The shapes of the transverse momentum and rapidity spectra from the p + d and p + p systems are found to be similar to one another for each of the beam energies studied. The beam energy dependence of the integrated cross sections is also presented.

Effect of molasses, sodium bentonite and zeolite on urea toxicity

Molasses, sodium bentonite (montmorillonite clay) and zeolite (crushed clinoptilolite rock) were examined as supplement ingredients to improve the safety margin of urea supplementation in a series of seven experiments. These experiments were designed to provide an understanding of the relationship between urea intake and the influence of the above ingredients on rumen pH and total ammonia concentrations. Rumen fistulated Merino ewes of 35-40 kg liveweight were administered various amounts of urea with and without supplement mixes. Rumen parameters were measured at 0, 0.5, 1-0, 1.5, 2.5, 5.0 and 24 h after treatment administration. Acetic acid and sucrose were also tested together with molasses for comparative effects on rumen parameters. In the last experiment, blood pH and total plasma ammonia were also determined. Free ammonia values of rumen liquor were calculated for experiments 2 to 7. In four experiments, molasses at 50, 100 and/or 150 g mixed with urea significantly reduced the normal rapid rise in ruminal pH, total and free ammonia values compared with urea (10 g) only treatments. In two experiments, associated presence or absence of clinical toxicity at various quantities of urea (8 to 25 g) with and without active ingredients confirmed the postive effect of molasses in preventing toxicity at <0.44 g urea/ kg liveweight. The addition of molasses reduced the increase in ruminal pH by up to 0-5 pH units and absolute values were consistently below pH 7-0. Sucrose (100 g) and acetic acid (800 mL of 1 M ) had the same and greater effect, respectively, compared with molasses (150 g) when added with urea (10 g) on ruminal pH and total and free ammonia changes over five hours post treatment. The partly hydrated urea / bentonite mix (approx 1 : 1 bentonite : water ratio) was associated with a delay in the increases in ruminal pH and free ammonia concentrations. Bentonite mixes, in either fully hydrated or fully dehydrated states, and zeolite mixes resulted in no significant effects. With reference to previous reports, the results support the positive role of a stable acid pH in the rumen for ensuring safe urea supplementation.

A formula for comparison of selected sport ball compressibility

The purpose of this study was to develop a formula to determine and compare the compressibility of selected sport balls. Six balls (basketball, volleyball, soccer ball, baseball, handball, golf ball) were dropped ten times from each of four different heights onto a smooth solid surface overlaid with a white sheet of typing paper, overlaid with a sheet of carbon paper. The diameter of the area of contact of each ball imprinted onto the typing paper was measured in millimetres with calipers. From the data, the distance (d) that each ball compressed for each velocity (v) was calculated. It was found that a linear relationship existed between velocity at impact and the distance for each ball studied. The compressibility coefficient (c) for each ball was calculated and a formula was developed to determine the distance each ball would compress at a given velocity. When velocity is measured in metres per second and the distance a ball compresses is measured in millimetres, the formula to determine d for selected balls, in order of compressibility is: basketball d = 3.07v, volleyball d = 2.90v, soccer ball d = 2.80v, baseball d = 0.77v, handball d = 0.53v, and golf ball d = 0.17v.

Lipid composition of functional domains of the lymphocyte plasma membrane

Plasma membrane vesicles from calf T-lymphocytes were fractionated by affinity chromatography on Con A-Sepharose. One subfraction eluted freely from the affinity column (fraction 1), while a second one adhered specifically to the column (fraction 2). While both fractions were derived exclusively from the plasma membrane, fraction 2 carried the high-affinity receptor for the mitogen concanavalin A and was distinct from fraction 1 with respect to its polypeptide pattern and the content of some plasma membrane-associated enzymes, suggesting the existence of functional plasma membrane domains. These functionally distinct fractions showed different lipid composition. The adherent fraction was enriched in phosphatidylcholine, while the relative amount of phosphatidylethanolamine and phosphatidylserine was reduced. Furthermore, the relative amount of saturated fatty acids was enhanced in the phospholipids of the adherent plasma membrane fraction. This could be shown in total phospholipids, as well as in separated individual phospholipids. We could therefore demonstrate that lipid heterogeneity may exist in plasma membranes of cells without structural polarity. Similar results were obtained when T-lymphocytes were stimulated with the mitogen concanavalin A. The functional domain, consisting of the high-affinity concanavalin A receptor, several enzymes and distinct lipid compositional pattern, thus seems to constitute a relatively stable structural entity of the lymphocyte plasma membrane.

Phospholipid and fatty acid composition of tetrodotoxin receptor-rich membrane fragments from Electrophorus electricus

To study the interaction of voltage-sensitive Na+-channels with membrane lipids, the phospholipid and fatty acid composition of highly purified membrane fragments from the remarkably differentiated plasma membrane of Electrophorus electricus has been analyzed. After density gradient fractionation and carrier free electrophoresis, fractions with up to 30 pmol tetrodotoxin binding/mg protein can be obtained, which may correspond to a 50% pure preparation of the extrasynaptic part of the excitable face. Phospholipid classes and cholesterol are separated by one-dimensional thin-layer chromatography in acidic and alkaline solvent systems. The following mean molar contents are found: 40% phosphatidylcholine, 23% phosphatidylserine, 30% phosphatidylethanolamine and 7% sphingomyelin. In a series of 11 animals, significant deviations from these mean values have been observed. The fatty acid composition of the phospholipids has been determined by gas chromatography. Phosphatidylcholine contains more than 50% 16:0, and about 20% unsaturated fatty acids in the C-18 group. Compared to other plasma membrane fractions, this phospholipid is the least differentiated. By contrast, phosphatidylethanolamine and phosphatidylserine show many characteristics in different membrane fractions, especially in their unsaturated components representing more than 50%. 22:6, as the major constituent in these fractions, accounts for a quarter to a third of all fatty acids in these fractions. 18:0 is the main saturated component in these two phospholipids with abundances of typically a quarter or less of all fatty acids. Knowledge of the lipid composition of these excitable membranes may help to conserve binding and structural properties when analyzing lipid-sensitive Na+-channels in vitro. It is also useful as a guideline for systematic reconstitution studies.

Solitary rhabdomyoma of the heart. Clinically silent case with sudden, unexpected death in an 11-month-old boy

We report a case of cardiac rhabdomyoma leading to sudden, unexpected death in an 11-month-old child. Autopsy disclosed a firm nodular tumor located in the anterior part of the interventricular septum and anterior wall of the left chamber. The tumor bulged into the cavity of the ventricle and caused appreciable narrowing of the outflow tract. Histologically, the typical "spider cells" characteristic for cardiac rhabdomyoma could be found. Sections cut from alcohol-fixed tissues and stained in water-free PAS showed that these cells contained massive amounts of diastase-digestible PAS-positive material, presumably glycogen. No evidence of tuberous sclerosis was detected. Sudden death was attributed to cardiac arrest due to irritation of the conducting system by the tumor.

[Interaction between alpha-2 macroglobulin and trypsin with synthetic trypsin inhibitors]

The complex formed between trypsin (Tn) and alpha 2 Macroglobulin (alpha 2 M) retains the whole hydrolytic activity of the enzyme for synthetic substrates. Moreover synthetic inhibitors of low molecular weight stiel inhibit this activity. A comparative study of three inhibitors (Benzylamine, Butylamine, Benzamidine) has been carried out and shows that their behavior is similar. These inhibitors bind trypsin when it is bound to alpha 2 M and reciprocally alpha 2 M can bind Tn-inhibitor complex. Nevertheless the dissociation constant of the enzyme-inhibitor complex (Ki) is increased by alpha 2 M. In the case of Benzamidine the value of Ki is 2.22.10(-5) M for native enzyme and 13.4.10(-5) M for Tn-alpha 2 M and in the case of Butylamine this value increases from 0.5.10(-3) M to 2.95.10(-3) M. These variations of the Ki values are due to the modification of the accessibility of the inhibitor to the active site. Unpublished results show that the alpha 2 M molecule undergoes a deep structural modification in the course of the complex formation, which must lead to an increase of the value of Ki. This structural modification is probably irreversible so that the alpha 2 M complex has never been dissociated without altering the alpha 2 M molecule. The increase of the values of Ki cannot therefore result in an effective decrease of the association constant of the Tn-alpha 2 M complex.

Mitigation of hyperacute rejection by antilymphocyte globulin (ALG)

In HR, primarily humoral immunologic factors trigger a sequence of events that finally destroys the transplanted organ. Unspecific trapping of WBC diminishes the RBF, especially in the first compartment--the cortex. Pretreatment with ALG is able to suppress this cellular participation partially, thus postponing the stop of RBF without preventing the influence of humoral factors on the graft. As shown by pathologic and functional criteria recorded for 8 hr, an exclusive measurement of total RBF does not reflect an inhibition of the course of HR.

[Model of the interaction between trypsin and alpha 2-macroglobulin of porcine serum]

A comparative study of the dissociation into subunits of Porcine alpha2 M, either native or bound to trypsin (Tn), has been carried out in order to determine the modifications of the alpha2 M structure due to the formation of the Tn-alpha2 M complex. Analytical ultra-centrifugation at pH 3.5 shows that the dissociation is smaller when alpha 2 M is bound to trypsin. Electrophoresis in 4% polyacrylamide gels, in presence of 0.1% SDS, of alpha2 M and Tn-alpha2 M incubated in 1% SDS leads to the same conclusion; the enzyme must stabilize the quaternay structure of alpha2 M. In presence of SDS + beta-mercaptoethanol, only a molecular weight (M.W.) 200,000 band is revealed in electrophoresis pattern of native alpha2 M. In the case of reduced Tn-alpha2 M, some other bands of M.W. 100,000, 50,000, 30,000 appear. When trypsin is inactivated by TLCK 100,000 M.W. band is present, accompanied by the 200,000 M.W. band whose intensity is function of the alpha2 M concentration. The 100,000 M.W. band appears therefore characteristic of the formation of the complex which must imply a proteolytic cleavage in the middle of the 100,000 polypeptidic chain of alpha2 M. A model of the complex is proposed in which the enzyme forms a proteic bridge between the two halves of the alpha2 M molecule.

Patterns of occlusion in 3-year-old Danish children

Occlusion and spacing patterns are described for 1,624 3-year-old children living in Gladsaxe, a suburb of Copenhagen. Normal transversal relations were found in 1,396 children, while 214 had crossbite, and 14 had scissors-bite. The sagittal and vertical occlusion were significantly different in the three groups. The sagittal occlusion characters were to a large extent identical in the second primary molar, the canine and the incisor regions in the individual child. Open bite was much more frequent in children with maxillary overjet greater than 4 mm than in children with maxillary overjet greater than or equal to 4 mm. Definite mandibular overjet was diagnosed in three children but 19 had a tendency towards mandibular overjet. The number of dummy suckers was very high and significantly higher among children with crossbite than amoung children with normal transversal relations. Crowding was found in the incisor regions, but very seldom, while total spacing existed in 34.5% of the maxillary and 24.3% of the mandibular arches.

Animal DNA-dependent RNA polymerases. Purification and molecular structure of hen-oviduct and liver class-B RNA polymerases

Hen ovidcut and liver class B RNA polymerases have been extensively purified and their molecular structure has been analysed. While only one enzyme B form (BIIb) was found in liver, three forms (BI, BIIa and BIIb) were resolved from oviduct. The molecular structures of the various class B RNA polymerase forms purified from hen oviduct and liver are identical to the corresponding forms previously purified from calf thymus and rat liver. At the present level of resolution the only difference lies in a slight difference in the charge of one subunit (SB2a) of enzyme form BIIa, when comparing the mammal and bird enzymes. It is unlikely that the absence of enzyme forms BI and BIIa in purified hen liver RNA polymerase B could be related to limited and specific proteolysis during the purification, since co-purification of oviduct and liver RNA polymerase B activities from a mixture of oviduct and liver nuclei does not affect the presence of either oviduct enzyme form BI or BIIa in the final purified mixture.

Mise en evidence de la formation d'un complexe ternaire entre trypsine, α2 -macroglobuline et inhibiteur basique de pancreas

The complex formed between trypsin and alpha(2)-macroglobulin retains the whole hydrolytic activity for benzoylarginine-p-nitroanilide (DL BAPNA). We have observed that the inhibition of this activity is dependent on the inhibitor used. While soya bean inhibitor (MW = 20 000) is ineffective, the basic pancreatic inhibitor (MW = 6 500) progressively inhibits the complex. In this latter case, we have observed the formation of a very weakly active ternary compound by two methods: kinetic and fluorescence polarization.Such differences suggest either that the contact site of trypsin for binding is not the same for each inhibitor or that the steric hindrance by macroglobulin prevents large inhibitors from reaching the active site. The pancreatic inhibitor can reach this site but its affinity is lower for the complex than for free trypsin.