T-cell-mediated association of peptide antigen and major histocompatibility complex protein detected by energy transfer in an evanescent wave-field

Helper T cells recognize foreign antigen displayed on antigenpresenting cells which also express self-molecules of the major histocompatibility complex (MHC). A single T-cell receptor mediates recognition of both MHC and foreign antigen. A proposed ternary complex between T-cell receptor, foreign antigen and MHC antigen has not yet been demonstrated (see ref. 1 for review). Here, we show that a fluorescein-labelled synthetic peptide, together with Texas red-labelled class II MHC antigen, I-Ad, stimulates the production of interleukin-2 by a peptide-specific I-Ad-restricted T-cell hybridoma when reconstituted in a lipid membrane on a glass substrate. Under the same conditions, resonance-energy transfer from donor peptide to acceptor I-A can be stimulated in an evanescent wave-field only in the presence of the specific T-hybrid. Our results show that the T cell stabilizes an association between peptide antigen and class II MHC protein to within a distance of about 40 A.     

Inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia is caused by mutant valosin-containing protein

Inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia (IBMPFD) is a dominant progressive disorder that maps to chromosome 9p21.1-p12. We investigated 13 families with IBMPFD linked to chromosome 9 using a candidate-gene approach. We found six missense mutations in the gene encoding valosin-containing protein (VCP, a member of the AAA-ATPase superfamily) exclusively in all 61 affected individuals. Haplotype analysis indicated that descent from two founders in two separate North American kindreds accounted for IBMPFD in approximately 50% of affected families. VCP is associated with a variety of cellular activities, including cell cycle control, membrane fusion and the ubiquitin-proteasome degradation pathway. Identification of VCP as causing IBMPFD has important implications for other inclusion-body diseases, including myopathies, dementias and Paget disease of bone (PDB), as it may define a new common pathological ubiquitin-based pathway.     

Early human use of marine resources and pigment in South Africa during the Middle Pleistocene

Genetic and anatomical evidence suggests that Homo sapiens arose in Africa between 200 and 100 thousand years (kyr) ago, and recent evidence indicates symbolic behaviour may have appeared approximately 135-75 kyr ago. From 195-130 kyr ago, the world was in a fluctuating but predominantly glacial stage (marine isotope stage MIS6); much of Africa was cooler and drier, and dated archaeological sites are rare. Here we show that by approximately 164 kyr ago (+/-12 kyr) at Pinnacle Point (on the south coast of South Africa) humans expanded their diet to include marine resources, perhaps as a response to these harsh environmental conditions. The earliest previous evidence for human use of marine resources and coastal habitats was dated to approximately 125 kyr ago. Coincident with this diet and habitat expansion is an early use and modification of pigment, probably for symbolic behaviour, as well as the production of bladelet stone tool technology, previously dated to post-70 kyr ago. Shellfish may have been crucial to the survival of these early humans as they expanded their home ranges to include coastlines and followed the shifting position of the coast when sea level fluctuated over the length of MIS6.     

Progress in screening for inborn errors of metabolism

Summary The inborn errors of metabolism are a series of individually rare biochemical anomalies some of which cause serious clinical manifestations. They are of great interest to biochemists and geneticists, as well as to paediatricians and internist for whom they often present special diagnostic and therapeutic problems. The study of the inborn errors of metabolism also has implications in the fields of epidemiology and social medicine. The number of known inborn errors of metabolism has increased rapidly in recent years, and others, as yet unidentified, presumably await recognition. Only a few of these conditions can be treated now, but the realisation that early diagnosis is essential in order to achieve good results has stimulated interest in the possibility of examining either whole populations or selected predisposed groups of individuals for biochemical differences which characterise particular inherited metabolic diseases.This article reviews some recent developments with particular reference to the indications for such screening programmes and progress in the identification of previously unknown inborn errors of metabolism in otherwise homogeneous population groups. — The inborn errors of metabolism are due to single gene mutations. — Recognition of the asymptomatic individuals who are heterozygous for the abnormal gene causing the disease may be important clinically and the identification of these individuals has to be considered as one aspect of metabolic screening for the inborn errors of metabolism.     

Mutations in SEPT9 cause hereditary neuralgic amyotrophy

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant recurrent neuropathy affecting the brachial plexus. HNA is triggered by environmental factors such as infection or parturition. We report three mutations in the gene septin 9 (SEPT9) in six families with HNA linked to chromosome 17q25. HNA is the first monogenetic disease caused by mutations in a gene of the septin family. Septins are implicated in formation of the cytoskeleton, cell division and tumorigenesis.     

Cytoskeleton responses in wound repair

Wound repair on the cellular and multicellular levels is essential to the survival of complex organisms. In order to avoid further damage, prevent infection, and restore normal function, cells and tissues must rapidly seal and remodel the wounded area. The cytoskeleton is an important component of wound repair in that it is needed for actomyosin contraction, recruitment of repair machineries, and cell migration. Recent use of model systems and high-resolution microscopy has provided new insight into molecular aspects of the cytoskeletal response during wound repair. Here we discuss the role of the cytoskeleton in single-cell, embryonic, and adult repair, as well as the striking resemblance of these processes to normal developmental events and many diseases.     

Detection of human papillomavirus DNA in anogenital neoplasias

The presence of papillomaviruses in epithelial-derived cancers from several animal species has led to the speculation that these viruses may also have a pathogenic role in the development of certain human carcinomas, particularly those associated with the anogenital tract. Recently, human papillomavirus (HPV) DNA has been detected in epithelial-derived cancers, both cutaneous and metastatic, from patients exhibiting the rare, chronic flat wart disease, epidermodysplasia verruciformis (EV). Except for patients exhibiting this chronic wart syndrome, the association of HPV genomes with human epithelial cancers has not been demonstrated. In an attempt to delineate the association and possible involvement of papillomaviruses with human anogenital carcinomas, we have begun an analysis of these cancers for the presence of HPV-specific nucleotide sequences by using highly sensitive hybridization procedures capable of detecting distantly related papillomaviruses at low copy number. Here we demonstrate the presence of HPV DNA in several types of anogenital tumours: Bowenoid papulosis, carcinoma in situ, and verrucous carcinoma. These data indicate that HPV can be detected in several types of premalignant and malignant tumours, supporting the contention that this group of viruses may be involved in the development of certain types of human epithelial-derived cancers.