Novelty-induced memory consolidation is accompanied by increased Agap3 transcription: a cross-species study

Novelty-induced memory consolidation is a well-established phenomenon that depends on the activation of a locus coeruleus-hippocampal circuit. It is associated with the expression of activity-dependent genes that may mediate initial or cellular memory consolidation. Several genes have been identified to date, however, to fully understand the mechanisms of memory consolidation, additional candidates must be identified. In this cross-species study, we used a contextual novelty-exploration paradigm to identify changes in gene expression in the dorsal hippocampus of both mice and rats. We found that changes in gene expression following contextual novelty varied between the two species, with 9 genes being upregulated in mice and 3 genes in rats. Comparison across species revealed that ArfGAP with a GTPase domain, an ankyrin repeat and PH domain 3 (Agap3) was the only gene being upregulated in both, suggesting a potentially conserved role for Agap3. AGAP3 is known to regulate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptor trafficking in the synapse, which suggests that increased transcription of Agap3 may be involved in maintaining functional plasticity. While we identified several genes affected by contextual novelty exploration, we were unable to fully reverse these changes using SCH 23390, a dopamine D1/D5 receptor antagonist. Further research on the role of AGAP3 in novelty-induced memory consolidation could lead to better understanding of this process and guide future research.

Maternal Separation Followed by Chronic Mild Stress in Adulthood Is Associated with Concerted Epigenetic Regulation of AP-1 Complex Genes

Depression is one of the most prevalent mental diseases worldwide. Patients with psychiatric diseases often have a history of childhood neglect, indicating that early-life experiences predispose to psychiatric diseases in adulthood. Two strong models were used in the present study: the maternal separation/early deprivation model (MS) and the chronic mild stress model (CMS). In both models, we found changes in the expression of a number of genes such as Creb and Npy. Strikingly, there was a clear regulation of expression of four genes involved in the AP-1 complex: c-Fos, c-Jun, FosB, and Jun-B. Interestingly, different expression levels were observed depending on the model, whereas the combination of the models resulted in a normal level of gene expression. The effects of MS and CMS on gene expression were associated with distinct histone methylation/acetylation patterns of all four genes. The epigenetic changes, like gene expression, were also dependent on the specific stressor or their combination. The obtained results suggest that single life events leave a mark on gene expression and the epigenetic signature of gene promoters, but a combination of different stressors at different life stages can further change gene expression through epigenetic factors, possibly causing the long-lasting adverse effects of stress.

Relationship between natriuretic peptides and left atrial mechanics and their relation to recurrence of atrial fibrillation following catheter ablation

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation (grant no.: 09-04-R72-A2408-22545, 10-04-R78-A2929-22588, 11-04-R84-A3230-22650, and 18-R125-A8534-22083), and the Heart Centre Research Committee at Rigshospitalet, Copenhagen.

Background

The relationship between natriuretic peptides and atrial distension is not completely understood. Furthermore, how they can be used together clinically has not been fully explored.

Purpose

We sought to examine their interrelationship and how they relate to atrial fibrillation (AF) recurrence following catheter ablation.

Methods

Patients scheduled for catheter ablation as part of a randomized controlled clinical trial were included. Patients who underwent pre-operative echocardiography and had natriuretic peptide measurements performed, specifically mid-regional proANP (MR-proANP) and N-terminal proBNP (NT-proBNP), were included in this analysis. Echocardiography included assessment of atrial distension by left atrial strain.

The outcome was AF recurrence at 6 months after a 3-month blanking period. Logistic regression was performed to assess the association between log-transformed natriuretic peptides and AF. Multivariable adjustments were made for age, gender, randomization, and LVEF.

Results

Out of 99 patients 44 developed AF. No differences in natriuretic peptides nor echocardiographic measures were observed between the outcome groups.

Neither MR-proANP nor NT-proBNP were univariable predictors of AF recurrence (MR-proANP: OR = 1.06 (0.99-1.14), p = 0.09, per 10% increase; NT-proBNP: OR = 1.01 (0.98-1.05), p = 0.38, per 10% increase). These findings were unchanged after multivariable adjustments. However, atrial strain significantly modified the association between MR-proANP and AF (p for interaction = 0.009) such that MR-proANP was a significant predictor of AF in patients with high atrial strain values (OR = 1.24 (1.06-1.46), p = 0.008, per 10% increase) but not in patients with low atrial strain values. Among patients with high atrial strain values, an MR-proANP > 116pmol/L was associated with a 10-fold increased risk of AF (OR = 9.78 (2.21-43.33), p = 0.003). figure.

Conclusion

Atrial natriuretic peptide predicts AF recurrence in patients with preserved atrial distension. Assessing atrial distension by echocardiography may assist the clinical interpretation of atrial natriuretic peptide concentration.

Abstract Figure.

Association between natriuretic peptides and left atrial structural and functional properties in atrial fibrillation following catheter ablation

Background

Atrial natriuretic peptides (ANP) and brain natriuretic peptides (BNP) are acutely released from the atrial myocytes upon increased mechanical distension of the atria. The relationship between imaging measures of left atrial (LA) structure and function and natriuretic peptides following catheter ablation (CA) have not been clearly delineated.

Purpose

To characterize the relationship between LA structure and function and natriuretic peptides.

Methods

We performed an echocardiographic substudy of a randomized trial of AF patients scheduled for CA. Echocardiographic measurements included: LA volume at end-systole (LAVi), at end-diastole (LAEDVi), emptying fraction (LAEF), LA reservoir strain (LAs), and global longitudinal strain (GLS). Patients were stratified by tertiles of mid-regional proANP (MR-proANP) concentrations in circulation (<92 pmol/l, 92–146 pmol/l, >146 pmol/l), and NT-proBNP (<10pmol/l, 10–38 pmol/l, >38 pmol/l). Linear regressions were performed to compare baseline echocardiographic measures to natriuretic peptide concentrations at baseline, 1 month, 3 months and 6 months of follow-up. MR-proANP and NT-proBNP were logarithm transformed in these analyses. Multivariable adjustments were made for: age, gender, AF subtype, AF burden, rhythm during echocardiogram, rhythm at study visit for blood sampling, time known with AF, beta-blocker use, and CHA-2DS2-VASc score.

Results

We included 101 patients with AF. The mean age was 58 years, 82% were men, 46% had persistent AF. Increasing tertiles of MR-proANP at baseline were associated with abnormal LA size and function (3rd vs 1st tertile: LAVi: 42mL/m2 vs 32mL/m2; LAEDVi: 31mL/m2 vs 20mL/m2; LAEF: 38% vs 26%; LAs: 27% vs 19%; GLS: −18% vs −14%) whereas both LA and left ventricular measures were associated with increasing NT-proBNP concentrations at baseline. After multivariable adjustments, only LA volumes and LAEF remained significantly associated with MR-proANP, whereas only LA volumes and GLS remained significantly associated with NT-proBNP. At follow-up, impaired LA function associated with persistently elevated concentrations, which was not the case for LAVi (figure).

Conclusion

MR-proANP reflects LA dysfunction better than NT-proBNP. Measures of LA function rather than LAVi associates with persistently elevated natriuretic peptide concentrationsw, which may indicate that functional measures are more closely associated with evidence of LA myocardial stretch than LAVi.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Danish Heart Foundation

Long-Term Stress Disrupts the Structural and Functional Integrity of GABAergic Neuronal Networks in the Medial Prefrontal Cortex of Rats

Clinical and experimental data suggest that fronto-cortical GABAergic deficits contribute to the pathophysiology of major depressive disorder (MDD). To further test this hypothesis, we used a well characterized rat model for depression and examined the effect of stress on GABAergic neuron numbers and GABA-mediated synaptic transmission in the medial prefrontal cortex (mPFC) of rats. Adult male Wistar rats were subjected to 9-weeks of chronic mild stress (CMS) and based on their hedonic-anhedonic behavior they were behaviorally phenotyped as being stress-susceptible (anhedonic) or stress-resilient. Post mortem quantitative histopathology was used to examine the effect of stress on parvalbumin (PV)-, calretinin- (CR), calbindin- (CB), cholecystokinin- (CCK), somatostatin-(SST) and neuropeptide Y-positive (NPY+) GABAergic neuron numbers in all cortical subareas of the mPFC (anterior cingulate (Cg1), prelimbic (PrL) and infralimbic (IL) cortexes). In vitro, whole-cell patch-clamp recordings from layer II–III pyramidal neurons of the ventral mPFC was used to examine GABAergic neurotransmission. The cognitive performance of the animals was assessed in a hippocampal-prefrontal-cortical circuit dependent learning task. Stress exposure reduced the number of CCK-, CR- and PV-positive GABAergic neurons in the mPFC, most prominently in the IL cortex. Interestingly, in the stress-resilient animals, we found higher number of neuropeptide Y-positive neurons in the entire mPFC. The electrophysiological analysis revealed reduced frequencies of spontaneous and miniature IPSCs in the anhedonic rats and decreased release probability of perisomatic-targeting GABAergic synapses and alterations in GABA_B receptor mediated signaling. In turn, pyramidal neurons showed higher excitability. Anhedonic rats were also significantly impaired in the object-place paired-associate learning task. These data demonstrate that long-term stress results in functional and structural deficits of prefrontal GABAergic networks. Our findings support the concept that fronto-limbic GABAergic dysfunctions may contribute to emotional and cognitive symptoms of MDD.

Chronic stress reduces the number of GABAergic interneurons in the adult rat hippocampus, dorsal-ventral and region-specific differences

Major depressive disorder is a common and complex mental disorder with unknown etiology. GABAergic dysfunction is likely to contribute to the pathophysiology since disrupted GABAergic systems are well documented in depressed patients. Here we studied structural changes in the hippocampal GABAergic network using the chronic mild stress (CMS) model, as one of the best validated animal models for depression. Rats were subjected to 9 weeks of daily stress and behaviorally characterized using the sucrose consumption test into anhedonic and resilient animals based on their response to stress. Different subtypes of GABAergic interneurons were visualized by immunohistochemistry using antibodies for parvalbumin (PV), calretinin (CR), calbindin (CB), cholecystokinin (CCK), somatostatin (SOM), and neuropeptide Y (NPY). We used an unbiased quantification method to systematically count labeled cells in different subareas of the dorsal and ventral hippocampus. Chronic stress reduced the number of specific interneurons in distinct hippocampal subregions significantly. PV+ and CR+ neurons were reduced in all dorsal subareas, whereas in the ventral part only the CA1 was affected. Stress had the most pronounced effect on the NPY+ and SOM+ cells and reduced their number in almost all dorsal and ventral subareas. Stress had no effect on the CCK+ and CB+ interneurons. In most cases the effect of stress was irrespective to the behavioral phenotype. However, in a few specific areas the number of SOM+, NPY+, and CR+ neurons were significantly reduced in anhedonic animals compared to the resilient group. Overall, these data clearly demonstrate that chronic stress affects the structural integrity of specific GABAergic neuronal subpopulations and this should also affect the functioning of these hippocampal GABAergic networks.

Diffusion kurtosis imaging and high-resolution MRI demonstrate structural aberrations of caudate putamen and amygdala after chronic mild stress

The pathophysiology of major depressive disorder (MDD) and other stress related disorders has been associated with aberrations in the hippocampus and the frontal brain areas. More recently, other brain regions, such as the caudate nucleus, the putamen and the amygdala have also been suggested to play a role in the development of mood disorders. By exposing rats to a variety of stressors over a period of eight weeks, different phenotypes, i.e. stress susceptible (anhedonic-like) and stress resilient animals, can be discriminated based on the sucrose consumption test. The anhedonic-like animals are a well validated model for MDD. Previously, we reported that in vivo diffusion kurtosis imaging (DKI) of the hippocampus shows altered diffusion properties in chronically stressed rats independent of the hedonic state and that the shape of the right hippocampus is differing among the three groups, including unchallenged controls. In this study we evaluated diffusion properties in the prefrontal cortex, caudate putamen (CPu) and amygdala of anhedonic-like and resilient phenotypes and found that mean kurtosis in the CPu was significantly different between the anhedonic-like and resilient animals. In addition, axial diffusion and radial diffusion were increased in the stressed animal groups in the CPu and the amygdala, respectively. Furthermore, we found that the CPu/brain volume ratio was increased significantly in anhedonic-like animals as compared with control animals. Concurrently, our results indicate that the effects of chronic stress on the brain are not lateralized in these regions. These findings confirm the involvement of the CPu and the amygdala in stress related disorders and MDD. Additionally, we also show that DKI is a potentially important tool to promote the objective assessment of psychiatric disorders.

Electroconvulsive stimulation reverses anhedonia and cognitive impairments in rats exposed to chronic mild stress

Electroconvulsive therapy remains the most effective treatment for depression including a fast onset of action. However, this therapeutic approach suffers from some potential drawbacks. In the acute phase this includes amnesia. Electroconvulsive stimulation (ECS) has previously been shown to reverse a depression-like state in the chronic mild stress model of depression (CMS), but the effect of ECS on cognition has not previously been investigated. In this study the CMS model was used to induce a depressive-like condition in rats. The study was designed to investigate the acute effect of ECS treatment on working memory and the chronic effect of repeated ECS treatments on depression-like behavior and working memory. The results indicated that, in the acute phase, ECS treatment induced a working memory deficit in healthy controls unexposed to stress, while repeated treatments reversed stress-induced decline in working memory, as well as recovering rats submitted to the CMS paradigm from the anhedonic-like state. Like in the clinical setting, a single ECS exposure was ineffective in inducing remission from a depression-like state.

Candidate hippocampal biomarkers of susceptibility and resilience to stress in a rat model of depression

Susceptibility to stress plays a crucial role in the development of psychiatric disorders such as unipolar depression and post-traumatic stress disorder. In the present study the chronic mild stress rat model of depression was used to reveal stress-susceptible and stress-resilient rats. Large-scale proteomics was used to map hippocampal protein alterations in different stress states. Membrane proteins were successfully captured by two-phase separation and peptide based proteomics. Using iTRAQ labeling coupled with mass spectrometry, more than 2000 proteins were quantified and 73 proteins were found to be differentially expressed. Stress susceptibility was associated with increased expression of a sodium-channel protein (SCN9A) currently investigated as a potential antidepressant target. Differential protein profiling also indicated stress susceptibility to be associated with deficits in synaptic vesicle release involving SNCA, SYN-1, and AP-3. Our results indicate that increased oxidative phosphorylation (COX5A, NDUFB7, NDUFS8, COX5B, and UQCRB) within the hippocampal CA regions is part of a stress-protection mechanism.

Hippocampal GABAergic dysfunction in a rat chronic mild stress model of depression

In major depression, one line of research indicates that a dysfunctional GABAergic inhibitory system is linked to the appearance of depressive symptoms. However, as the mechanistic details of such GABAergic deficit are largely unknown, we undertook a functional investigation of the GABAergic system in the rat chronic mild stress model of depression. Adult rats were exposed to an eight-week long stress protocol leading to anhedonic-like behavior. In hippocampal brain slices, phasic, and tonic GABA(A) receptor-mediated currents in dentate gyrus granule cells were examined using patch-clamp recordings. In granule cells, the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) was reduced to 41% in anhedonic-like rats, which was associated with a reduced probability of evoked GABA release. Using immunohistochemical analysis, there was no change in the number of parvalbumin-positive interneurons in the dentate gyrus. Notably, we observed a 60% increase in THIP-activated tonic GABA(A) mediated current in anhedonic-like rats, suggesting an upregulation of extrasynaptic GABA(A) receptors. Finally, five weeks treatment with the antidepressant escitalopram partially reversed the sIPSCs frequency. In summary, we have revealed a hippocampal dysfunction in the GABAergic system in the chronic mild stress model of depression in rats, caused by a reduction in action potential-dependent GABA release. Since the function of the GABAergic system was improved by antidepressant treatment, in parallel with behavioral read outs, it suggests a role of the GABAergic system in the pathophysiology of depression.

Nicotine reverses anhedonic-like response and cognitive impairment in the rat chronic mild stress model of depression: comparison with sertraline

Smoking rates among depressed individuals are higher than is observed in the background population, and nicotine alleviates depressive symptoms. In rodents, nicotine shows antidepressant-like effects in the forced swim and learned helplessness paradigms. Clinical depression is associated with both anhedonia and cognitive impairments. In rats, chronic mild stress (CMS) decreases voluntary sucrose intake, reflecting an anhedonic-like state, and impairs performance in the spontaneous alternation behaviour (SAB) test, suggesting impaired cognitive function. Here, we examine the effect of chronic treatment of nicotine (0.4 mg/kg/day) and sertraline (5 mg/kg/day) on CMS-induced anhedonic-like behaviour and impairment in the SAB test. Nicotine and sertraline administered individually or in combination show significant and equally efficacious reversal of the CMS-induced decrease in sucrose intake, implying there is no additive or synergistic effect of the nicotine + sertraline combination. In the SAB test, nicotine, but not sertraline or nicotine + sertraline, reversed the CMS-induced impairment. The present results show that the effect of nicotine on a CMS-induced anhedonic-like state in rats is similar to that of a standard antidepressant drug. Moreover, the data suggest that nicotine alleviates CMS-induced cognitive disturbance. A treatment strategy involving the targeting of nicotinic acetylcholine receptors may prove beneficial for emotional and cognitive disturbances associated with depression.

Postnatal neurogenesis in the hippocampal dentate gyrus and subventricular zone of the Göttingen minipig

Postnatal neurogenesis is currently viewed as important for neuroplasticity and brain repair. We are, therefore, interested in animal models for neuroimaging of postnatal neurogenesis. A recent stereological study found an age-dependent increase in the number of neurons and glial cells in the neocortex of Göttingen minipigs, suggesting that this species may be characterized by a prolonged postnatal neurogenesis. Since there is no direct evidence on this issue, the goal of our study was to quantify cell proliferation in the two major neurogenic regions of the postnatal brain - the subventricular zone of the lateral ventricle (SVZ) and the hippocampal dentate gyrus (DG) - at two separate points during the lifespan of the minipig. Göttingen minipigs aged 6-7 and 32 weeks were injected with bromodeoxyuridine (BrdU), a marker of cycling cells, and killed after 2h. We found BrdU-positive cells numbering 165,000 in the SVZ and 35,000 in the DG at 6-7 weeks and 66,000 in the SVZ and 19,000 in the DG at 32 weeks-of-age. Stereology showed a 60% increase in the total number of DG granule cells between 6-7 and 32 weeks-of-age. Our findings show a continued postnatal neurogenesis in the major neurogenic regions of Göttingen minipigs, thereby providing a potential animal model for studies aimed at examining ongoing neurogenesis in the living brain with molecular neuroimaging technology.

A reduced number of hippocampal granule cells does not associate with an anhedonia-like phenotype in a rat chronic mild stress model of depression

Several clinical and preclinical studies have indicated that hippocampal shrinkage and decreased neurogenesis are implicated in the pathology of depression. Recent animal studies have shown, however, that the development of depression-related symptoms may take place through neurogenesis-independent pathways. To evaluate whether the stress-induced morphological changes in the hippocampal formation are causally related to the development of anhedonia-like symptoms, we combined the chronic mild stress (CMS) rat model of depression with stereological estimations of the number of proliferating progenitors, the total number of granule cells, and the volume of the ventral hippocampal formation (VHF). First, we found that stress-susceptible and stress-resilient animals, as categorized according to the behavioral read-out, both have a decrease in hippocampal cell proliferation. Our results also indicated that the anhedonia-like state in CMS rats develops prior to maximal suppression of cell proliferation, but correlates with a reduction in the total number of granule cells in the VHF. Furthermore, recovery from depression-related symptoms correlated with re-establishment of proliferation rates, but not with the total number of granule cells. Notably, decreases in the number of granule cells occurred independently of the induction of an anhedonia-like phenotype. There were no stress-induced changes in the volume of the VHF. We conclude that cell proliferation and a reduction in the total number of granule cells in the VHF are triggered by chronic stress, but do not associate with development of an anhedonia-like state in rats.

No fallacies in the formulation of the paternity index

In a recent publication, Li and Chakravarti claim to have shown that the paternity index is not a likelihood ratio. They present a method of estimating the prior probability of paternity from a sample of previous court cases on the basis of exclusions and nonexclusions. They propose calculating the posterior probability on the basis of this estimated prior and the test result expressed as exclusion/nonexclusion. Their claim is wrong--the paternity index is a likelihood-ratio, that is, the ratio of the likelihood of the observation conditional on the two mutually exclusive hypotheses. Their proposed method of estimating the prior has been long known, has been applied to several samples, and is inferior (in terms of variance of the estimate) to maximum likelihood estimation based on all the phenotypic information available. Their proposed "new method" of calculating a posterior probability is based on the use of a less informative likelihood ratio 1/(1-PE) instead of Gürtler's fully informative paternity index X/Y (Acta Med Leg Soc Liege 9:83-93, 1956), but is otherwise identical to the Bayesian approach originally introduced by Essen-Möller in 1938.

Atopic dermatitis. A genetic-epidemiologic study in a population-based twin sample

Atopic dermatitis is a multifactorial disease that seems both to rise in frequency and to be dependent on a genetic predisposition. In order to clarify these issues we encircled a representative twin series with atopic dermatitis from a total twin population of 592 like-sexed twin pairs. We found that the cumulative incidence rate (0-7 years) of atopic dermatitis in Denmark has increased significantly from 0.03 for the birth cohort 1960-1964 to 0.10 for the birth cohort 1970-1974, that monozygotic twin pairs are more often concordant for atopic dermatitis than dizygotic twin pairs, that monozygotic twins run a risk of 0.86 of having atopic dermatitis if the twin partner has the disease, whereas the disease risk of 0.21 run by dizygotic partners does not differ from the frequency seen in ordinary brothers and sisters. The results indicate that genetic factors play a decisive role in the development of atopic dermatitis and that widespread environmental factors are operating in genetically susceptible individuals.

Familial cranial diabetes insipidus: a report of five families. Genetic, diagnostic and therapeutic aspects

Five families were studied in which cranial diabetes insipidus occurred. In the pedigrees presented, the disease clearly followed an autosomal dominant mode of inheritance. Linkage analysis was performed in one large family by calculating lod scores for linkage between loci for cranial diabetes insipidus and 18 polymorphic markers and chromosome heteromorphisms. No significant genetic linkage was found and only one of the polymorphic markers gave a positive hint of linkage. A water deprivation test was performed in nine patients from three of the families and in healthy control subjects. The plasma concentration of arginine vasopressin was very low or undetectable in the patients, and unlike the control subjects did not increase significantly during water deprivation. Arginine vasopressin and serum osmolality (Sosm) were significantly positively correlated in the controls, but not in the patients. The results indicated that an arginine vasopressin-level lower than 2 pg/ml strongly suggests a diagnosis of cranial diabetes insipidus if at the same time Sosm is higher than 295 mosmol/kg. Studies with different intranasal dosages of 1-deamino-D-arginine-vasopressin (DDAVP) given once or twice a day showed that 20 micrograms effectively reduced urinary output and that administration once a day could be sufficient.

Linkage and chromosome study of multiple endocrine neoplasia IIa

A linkage and chromosome investigation of a large family with multiple endocrine neoplasia (MEN) IIa (medullary thyroid carcinoma, pheochromocytoma, and occasionally hyperparathyroidism) was undertaken. No significantly positive lodscores were obtained between MEN IIa and 25 different genetic markers. Conventional metaphase chromosome analysis showed normal karyotypes and no heterochromatin markers linked to the MEN IIa locus were found. High-resolution chromosome analysis in five MEN IIa carriers revealed no deletion within band 20p12.2. The present investigation could thus neither demonstrate linkage of the MEN IIa locus to genetic or chromosome markers nor identify chromosome abnormalities in MEN IIa carriers.

Partial deletion of the short arm of chromosome 3

A case of deletion of the short arm of chromosome 3 (46,XY,del(3)(p253) is described. The patient is a youth of 18 years in an institution for the mentally retarded. Phenotypically, he presents congenital heart disease, hypertelorism, ptosis, epicanthus, blepharophimosis, strabismus, nystagmus, synophrys, low-set ears, frequent infections, epilepsy (abnormal EEG and grand mal seizures), "rocker bottom" feet, flat occiput and muscular hypotonia. The parents are healthy and with normal karyotypes. A silent allele in the GPT system was found in the mother, the propositus and 4 of the 5 siblings.

A study of the linkage relations of epidermolysis bullosa dystrophica

Two large families from the Faroe Islands presenting epidermolysis bullosa of the dystrophic type were subjected to extensive linkage analyses with 22 serological markers. No significant evidence in support of linkage with any of these loci was provided. It was found to be very unlikely that the gene or genes causing the present types of epidermolysis bullosa belong to the EBS1 locus known to be closely linked to the GPT locus.

Successful nonsibling bone marrow transplantation in severe combined immunodeficiency

Severe combined immunodeficiency (SCID) was diagnosed in a girl immediately after birth; her older brother had SCID and was successfully reconstituted by bone marrow transplantation from his uncle. She was isolated in a laminar air flow bench and decontaminated. The father differed by one HLA-A antigen but was HLA-Dw2 homozygous like the patient; his lymphocytes showed a slight response to the patient's cells in mixed lymphocyte culture (MLC). At the age of 2 1/2 months and again at 5 months, she was given a bone marrow transplant from the father. During the entire course the patient had no infections, and apart from a transient eosinophilia she had no signs of graft-versus-host reaction. Immunological reconstitution was nearly complete at 9 months of age, when she was recontaminated. One year later plasma immunoglobulin concentrations are in the low normal range (IgG and IgM) or decreased (IgA); tests of cell-mediated immunity are normal. Apart from slight upper respiratory infections, the patient has been healthy. Physical and psychological development have been normal.

Metacarpal morphometry in monozygotic dizygotic elderly twins

The relative importance of genetic factors in the pathogenesis of age related bone loss has been investigated in a study involving 17 monozygotic (MZ) and 8 dizygotic (DZ) pairs of twins aged 64 to 75 years. Radiographic morphometry was performed at the midpoints of the 2nd, 3rd and 4th metacarpals of both hands and the mean total and cortical widths were evaluated. The heritability, h2, was calculated as the difference between the intrapair variances in same sexed DZ and MZ pairs divided by the intrapair variance in DZ pairs. The mean intrapair variance of both total and cortical width was found to be four to five times higher in DZ than in MZ pairs. The differences are highly significant with an h2 value between 0.7 and 0.8, indicating a predominant genetic influence. It is stressed that this result applies only to the population from which the twin sample was drawn.

Fluorescent Y-chromosomes in hairs and blood stains

Y-chromosome detection by way of fluorescence microscopy in biological materials has made sex determination possible in various areas of investigation. The present report describes the results of sex determination on hairs and blood stains. Significant differences were found between the Y-body count for female and male materials. In blind trials it was demonstrated that a reliable sex determination of hairs was possible for at least 27 weeks and of blood stains on cotton cloth and glass for 6 weeks. There were no false positive findings, but there was one male with a "female" blood smear count, who revealed an abnormally small fluorescent region on his Y-chromosome. The existence of such variants calls for caution when evaluating a low count.

Possible localization of Gc-System on chromosome 4. Loss of long arm 4 material associated with father-child incompatibility within the Gc-System

A mentally retarded girl with a sporadically occurring B/F translocation was reexamined with new banding techniques. Chromosome material from the long arm of chromosome 4 was inserted into the long arm of chromosome 20. The segment 4q11 leads to q13 was lost. The formerly reported abnormal segregation of the Gc-system was verified. The localization of the Gc-locus on the lost segment cannot be ruled out.

Data on the HL-A linkage group

Lod scores from a study in 229 families of the linkage relations of HL-A-PGM3 to 19 marker loci and cystic fibrosis are reported. The data exclude that ADA belongs to this linkage group while they give weak support for the inclusion of P. There is weak evidence for linkage of cystic fibrosis to PGM3, but none for linkage to HL-A. No new suggestive linkages appeared.

Haptoglobin type Hp-Jo and hypohaptoglobinaemia in a Danish family. Preliminary report

The occurrence of the rare Hp 2-Jo type in a Danish family is reported. By subtyping procedure the 2alphaJ polypeptide chain was demonstrated for the first time in an HP 2-Jo sample. Apparently independent of the transmission of the HpJo gene hypohaptoglobinaemia was found in a rather high proportion of the members of the kindred.

Amylo-1,60glucosidase deficiency (glycogenosis type III) in the Faroe Islands

Seven cases of glycogenosis type III (amylo-1,6-glucosidase deficiency) in two probably related families from the Faroe Islands are presented. The group of patients comprised two pairs of sibs. In a total of 78 members of the two families case histories were obtained and clinical examinations, analyses of amylo-1,6-glycosidase activity in erythrocytes and leucocytes, determinations of red cell, serum and enzyme groups as well as HL-A types were performed. In addition, all patients were subjected to studies of liver function. The distribution patients in these families supports the assumption of autosomal recessive inheritance. Heterozygotes could not be diagnosed with certainty by the methods of enzyme activity analysis employed. The incidence of glycogenosis type III with amylo-1,6-glucosidase deficiency was found to be high in the Faroe Islands.

Sex-linked hereditary thrombocytopenia with immunological defects

14 cases of severe thrombocytopenia in one family are presented. Case histories, clinical examination, analyses of platelets, haemoglobin, reticulocytes, leucocytes, eosinophilocytes, differential counts of leucocytes, serum immunoglobulin IgA, IgM, IgG, IgE concentrations, complement fixing platelet antibodies, isohaemagglutinins, colour perception, determination of red cell and serum groups as well as HL-A types were obtained from a total of 59 members of the family. The in vitro blast transformation response of blood lymphocytes was studied in 6 patients and 45 relatives. The pattern of transmission of the disease was in full agreement with X-linked recessive inheritance. Investigation of the immune system revealed impaired responses to microbial antigens in the 6 patients so studied. All relatives examined had normal haematological status, whereas approximately half showed a subnormal response to one microbial extract. The low responders were evenly distributed within the family, and it was not possible to correlate low response and presumed carrier state.

A group-C ring chromosome in a mentally deficient male

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