The postcranial skeletons of the Triassic mammals Eozostrodon, Megazostrodon and Erythrotherium.

The purposes of this monograph are to describe the postcranial skeletons of the earliest known mammals, and to probe, in so far as possible by osteological study, biological questions concerning the habits and adaptations of these late Triassic forms. In this context, information on the background of this investigation is useful. Studies of Mesozoic mammals, begun some 150 years ago, are based on rare and fragmentary fossils, principally jaws and teeth. These investigations have yielded a bare outline of some 120 million years of mammalian evolution-about two-thirds of mammalian history. No assessment of the important biological changes occurring during this time can ever be complete, but major advances are possible as new discoveries provide material that is more complete or that represents a previously unknown evolutionary stage. So tenuous is the evidence that at least some concepts are re-evaluated with each discovery. Postcranial anatomy offers especially intriguing prospects for investigation because associated material (that can be positively assigned to a taxon below subclass) has been for the most part unknown, and indeed even dissociated bones are a rarity. Since G.G. Simpson's monographs of 1928 and 1929, progress in the study of Mesozoic mammals has been largely dependent on new finds. A major impetus to renewed investigation came from the discoveries of Mesozoic mammals by Walter Kühne in 1939 and during the immediate post-war years. Kühne first worked on fissures in the Carboniferous limestone quarries at Frome, Somerset, in southwest England where he collected a series of teeth of the problematical form Haramiya and two triconodont teeth which were placed in the genus Eozostrodon (Parrington 1941, 1946). The fissure faunas are generally thought to be of Upper Triassic (Rhaetic) age (Kühne 1946), although Kermack, Musset & Rigney (1973) believe that the evidence is insufficient to determine whether the deposits are Rhaetic or Lower Liassic. After the war Kühne carried his explorations farther west, eventually reaching the quarries at Bridgend in Glamorgan, Wales, where he not only found more triconodont teeth in some quantity (Kühne 1958) but also a symmetrodont tooth (Kühne 1950). Shortly after making these discoveries, Kühne returned to Germany and the work was continued by a team from University College, London, under the leadership of Dr K.A. Kermack.     

The major human erythrocyte membrane protein. Evidence for an S-shaped structure which traverses the membrane twice and contains a duplicated set of sites.

The structure of the major human erythrocyte membrane protein (protein E) was investigated by studying the products of proteolysis of the native protein in the membrane. The distribution and location of the tyrosine residues labelled by radioiodination by lactoperoxidase was determined. Proteolysis of the extracellular region of the protein by thermolysin released four tyrosine-containing peptides, all of which were also found to remain in the major fragment that is retained in the membrane. The presence of these duplicated sites in the extracellular region of the protein was confirmed by limited trypsin digestion of the intracellular region of the protein. Two groups of fragments were obtained. Both groups contained a set of the extracellular labelled sites, but they differed in containing distinct groups of intracellular sites, showing that the two sets of extracellular sites are linked by an intracellular region of the protein. The polypeptide chain thus traverses the membrane twice. An S-shaped model which is consistent with these data is proposed.     

Effects of ovariectomy of the dogfish Scyliorhinus canicula L. on circulating levels of androgen and oestradiol and on pituitary gonadotrophin content

Levels of androgens and oestradiol in dogfish, Scyliorhinus canicula , plasma, measured by radioimmunoassay, decrease markedly after ovariectomy (OVX). The magnitude and latency of these responses varies according to length of captivity preceding the operation and the time of year at which ovariectomy is performed. Androgens are cleared more rapidly than oestradiol from plasma following OVX, and levels of both steroids are reduced after laparotomy (LAP) in November but not in March. An extract of ventral lobes of the dogfish pituitary induces a significant increase in the circulating androgen levels in LAP fish but not in OVX fish, indicating that the ovary is the major site of androgen production in response to stimulation by dogfish gonadotrophin. Intramuscular injections of oestradiol benzoate (2.5 mg per fish) into LAP fish produce a significant reduction in the gonadotrophin content of the pituitary ventral lobe, measured in the quail testicular cell bioassay, when compared to LAP and unoperated controls. However, no significant changes in the gonadotrophin content of the ventral lobe were seen five days after OVX in June.     

Regional co-ordinator for haemophilia in domiciliary practice.

The North-east Thames Region has appointed a nursing sister to co-ordinate the organisation of care for haemophiliacs in the region. As a result of the appointment, facilities for home treatment have expanded rapidly. Several associate centres providing care to haemophiliacs have been set up around the region in addition to the four main haemophilia centres, which are all in the south-west corner of the region. As well as providing support and supervision of patients on home treatment, the co-ordinator helps to place haemophiliac children in suitable schools, maintains the regional register of haemophiliacs, and has a more general role in ensuring that services are available where they are needed throughout the region.     

Catchment areas in general practice and their relation to size and quality of practice and deprivation: a descriptive study in one London borough.

OBJECTIVE: To relate the sizes of general practice catchment areas in one London borough to list size, deprivation payments, medical staffing, and locally and nationally recognised measures of quality. DESIGN: Study of general practice catchment area maps. SETTING: London borough of Lambeth. SUBJECTS: 60 out of the 71 general practices in Lambeth. MAIN OUTCOME MEASURES: Practice catchment area size with corrections for numbers of doctors and patients. RESULTS: Catchment area size varied greatly between practices, showing an almost 150-fold difference between the largest and smallest practices. This size differential was even more marked when the size of the catchment area was corrected for the number of general practitioners in the practice, where a 300-fold difference was found. Substantial differences existed between practices in each of the four locally assigned quality bands. The weakest practices had catchment areas three times as large as those of the strongest practices. When corrected for medical staffing, the difference was eight times as great. A calculated measure of patient dispersion showed that the practice population of the strongest practices was four times as densely clustered as that of the weakest practices, whose patients were more widely geographically dispersed. CONCLUSIONS: Large variations exist in the size of catchment areas of inner city practices even when corrected for numbers of doctors and patients. These differences are associated with variations in quality of care.     

Phenotypic profiling of mGlu7 knockout mice reveals new implications for neurodevelopmental disorders

Neurodevelopmental disorders are characterized by deficits in communication, cognition, attention, social behavior and/or motor control. Previous studies have pointed to the involvement of genes that regulate synaptic structure and function in the pathogenesis of these disorders. One such gene, GRM7, encodes the metabotropic glutamate receptor 7 (mGlu₇), a G protein‐coupled receptor that regulates presynaptic neurotransmitter release. Mutations and polymorphisms in GRM7 have been associated with neurodevelopmental disorders in clinical populations; however, limited preclinical studies have evaluated mGlu₇ in the context of this specific disease class. Here, we show that the absence of mGlu₇ in mice is sufficient to alter phenotypes within the domains of social behavior, associative learning, motor function, epilepsy and sleep. Moreover, Grm7 knockout mice exhibit an attenuated response to amphetamine. These findings provide rationale for further investigation of mGlu₇ as a potential therapeutic target for neurodevelopmental disorders such as idiopathic autism, attention deficit hyperactivity disorder and Rett syndrome.