Laminins are a family of multifunctional macromolecules, ubiquitous in basement membranes, and represent the most abundant structural noncollagenous glycoproteins of these highly specialised extracellular matrices. Their discovery started with the difficult task of isolating molecules produced by cultivated cells or extracted from tissues. The development of molecular biology techniques has facilitated and accelerated the identification and the characterisation of new laminin variants making it feasible to identify full-length polypeptides which have not been purified. Further, genetically engineered laminin fragments can be generated for studies of their structure-function relationship, permitting the demonstration that laminins are involved in multiple interactions with themselves, with other components of the basal lamina, and with cells. It endows laminins with a central role in the formation, the architecture, and the stability of basement membranes. In addition, laminins may both separate and connect different tissues, i.e. the parenchymal and the interstitial connective tissues. Laminins also provide adjacent cells with a mechanical scaffold and biological information either directly by interacting with cell surface components, or indirectly by trapping growth factors. In doing so they trigger and control cellular functions. Recently, the structural and biological diversity of the laminins has started to be elucidated by gene targeting and by the identification of laminin defects in acquired or inherited human diseases. The consequent phenotypes highlight the pivotal role of laminins in determining heterogeneity in basement membrane functions.

Experimental animal models are frequently used to study articular cartilage, but the relevance to man remains problematic. In this study animal models were compared by examination of the collagen fibre arrangement in the medial tibial plateau of human, cow, pig, dog, sheep, rabbit and rat specimens. 24 cartilage samples from each species were prepared and maximum cartilage thickness in the central tibial plateau measured. Samples were fixed, dehydrated, freeze-fractured and imaged by scanning electron microscopy (SEM). At low magnification, 2 different arrangements of collagen fibres were observed: leaf-like (human, pig, dog) and columnar (cow, sheep, rabbit, rat). The porcine collagen structure was the most similar to that of man. This arrangement was consistent from the radial to the upper zones. Under higher magnification at the surface of the leaves, the collagen was more randomly oriented, whereas the columns consisted of parallel collagen fibrils. The maximum thickness of cartilage did not correlate with the type of collagen arrangement but was correlated with the body weight of the species (r=0.785). When using animal models for investigating human articular cartilage function or pathology, the differences in arrangement of collagen fibres in tibial plateau cartilage between laboratory animals should be considered especially if morphological evaluation is planned.

Careful histological observation of the development of the anlage of the inner ear in chicken embryos led us to question the traditional view of otic placode (OP) formation. First, morphological studies in the cephalic region carried out on stages preceding the appearance of the placodal epithelium revealed that the medial placodal cells are continuous temporally and spatially with cells belonging to the neural fold (NF). Second, both the formation of the basal lamina between the dorsal region of the neural tube (NT) and ectoderm and the pattern of formation of the neural crest present distinctive characteristics between otic levels and regions located anteriorly and posteriorly. Third, numerical comparisons of parameters for the NT and the OP between different levels of the rhombencephalon allowed us to assign a differential behaviour in the growth pattern of the otic region. These results indicated that the medial part of the OP is not derived from already independent ectoderm that increases in thickness under the influence of the NT (as previously accepted) but that it develops directly from the NFs. Although we do not exclude other possibilities, we propose that at least a proportion of the OP cells originate directly from cells committed to be neural crest. After this incorporation, basal laminal formation would delimit the NT from the OP without transition of the otic cells to ectoderm. This hypothesis would imply that part of the otic cells originate directly from neuroepithelial cells having a neuroectodermal (rather than the previously established ectodermal) origin.

The reactive formation of lymphoid follicles and germinal centres in lymph nodes, induced by subcutaneous transfer of in vitro activated splenic adherent cells into syngeneic mice, were studied. Adherent cells were obtained by incubating spleen cell suspensions for 24 h and activated by incubating for 1 h in the medium containing keyhole limpet haemocyanin (KLH) absorbed onto alumina. Some of the treated adherent cells were irradiated with 10 Gy x-rays, while others were either not stimulated or were stimulated with alumina-KLH but killed by repeated freezing and thawing. Examination of adherent cell smears immunostained with antibodies against, F4/80, Mac-1, Mac-2 and NLDC-145 indicated that many adherent cells displayed macrophage markers but few displayed the interdigitating cell marker. Animals transfused with KLH-treated adherent cells with or without irradiation showed a marked increase in the number of lymphoid follicles and germinal centres in draining lymph nodes, whereas those transfused with adherent cells which had not been KLH-treated or which had been killed after KLH treatment displayed no significant change in the number of follicles. These results were interpreted as indicating that following transfusion, antigen-activated adherent macrophages migrated into the draining lymph nodes and induced the reactive formation of lymphoid follicles and germinal centres outside preexisting follicles.

Associated skeletons, which are specimens preserving more than one body part from the same individual, are especially important for taxonomic and functional analyses. This study concentrates on the subset of associated skeletons which preserve the reciprocal surfaces of a joint. It uses laser scanning to explore whether the shapes of the reciprocal surfaces of a joint of an individual are significantly more congruent than the surfaces of randomly-matched pairings taken from the same species. Laser scanning was used to capture the distal articular surface of the left tibia of OH35 and the trochlear articular surface of the talus of OH8, both from Bed I, Olduvai Gorge, Tanzania. The degree of congruency between those articular surfaces was tested against the congruency of the talocrural joint of AL 288-1 (Australopithecus afarensis), and the congruency of both associated and randomly-matched talocrural joints of modern humans, chimpanzees and gorillas. The results suggest that OH35 and OH8 do not come from the same individual and may not come from the same species. Although this analysis leaves open the taxonomic affinity of OH35, it demonstrates the potential of laser scanning for capturing 3D data in palaeoanthropology. It also demonstrates the potential for using the relative congruency of reciprocal joint surfaces as a test of the likelihood that isolated limb bones are components of a single individual.

Changes in the shape of erythrocytes circulating in large blood vessels of mice were examined by our ‘in vivo cryotechnique’. The abdominal aorta and inferior vena cava (IVC) were cut vertically with a precooled knife and simultaneously an isopentane–propane mixture (−193°C) was poured over them for freezing. They were freeze-substituted in acetone containing 2% osmium tetroxide. Some specimens were embedded in Quetol-812, and thick or ultrathin sections were examined by light or transmission electron microscopy. Serial ultrathin sections were used to reconstruct 3-dimensional images of native erythrocytes. Others were transferred into t-butyl alcohol and freeze-dried for scanning electron microscopy. The tissue surfaces were sufficiently frozen to prevent large ice crystal formation, and erythrocyte shapes were also preserved. The shapes of circulating erythrocytes appeared to be varied in the abdominal aorta but typical biconcave discoid shapes were rarely observed. Conversely, erythrocytes were approximately biconcave discoid in shape in the IVC. Our in vivo cryotechnique was useful for clarifying the in vivo morphology of erythrocytes circulating in large blood vessels.

We report the morphogenesis of a new mouse mutant, Doublefoot (Dbf). The major phenotypic features involve the limb and craniofacial regions. There is polydactyly of all 4 limbs, with typically 6–8 digits per limb. All of the digits are triphalangeal; some show bifurcations and some are not attached to the carpus/tarsus. The carpus and tarsus are broader than normal, and their elements are partially fused. There are also tibial defects. Mutant embryos show a diencephalic bulge on d 10.0, with older animals exhibiting broadened and bulbous skulls sometimes with an additional midline skeletal element, shortened snouts and bulging eyes. Homozygotes, which do not survive beyond d 15, show midline facial clefting. In this study of the embryonic and fetal development of Dbf animals, we focus on the morphogenesis of the limbs and head, and discuss the possible molecular developmental mechanisms.

Mobilisation of the latissimus dorsi muscle as a functional graft necessarily involves division of perforating arteries that enter the distal portion of the muscle, rendering it vulnerable to ischaemic damage when the muscle is stimulated electrically. Using a fluorescent microsphere technique we showed that the blood flow contributed by the thoracodorsal artery decreases in a proximal-to-distal direction, and that of the perforating arteries in a distal-to-proximal direction, but for neither does the flow decline to zero. This is consistent with earlier reports of anastomotic connections between the 2 arterial territories. We went on to use fluorescence microscopy to demonstrate the existence of these vascular anastomoses, the first such evidence obtained under physiological conditions of pressure and flow. In clinical applications, the existence of anastomotic connections offers the prospect of maintaining flow to the distal part of the grafted muscle without the delays inherent in neovascularisation procedures.

Transgenic technology has potentially solved many of the immunological difficulties of using pig organs to support life in the human recipient. Nevertheless, other problems still remain. Knowledge of cardiac anatomy of the pig (Sus scrofa) is limited despite the general acceptance in the literature that it is similar to that of man. A qualitative analysis of porcine and human cardiac anatomy was achieved by gross examination and dissection of hearts with macrophotography. The porcine organ had a classic ‘Valentine heart’ shape, reflecting its location within the thorax and to the orientation of the pig's body (unguligrade stance). The human heart, in contrast, was trapezoidal in silhouette, reflecting man's orthograde posture. The morphologically right atrium of the pig was characterised by the tubular shape of its appendage (a feature observed on the left in the human heart). The porcine superior and inferior caval veins opened into the atrium at right angles to one another, whereas in man the orifices were directly in line. A prominent left azygous vein (comparable to the much reduced left superior caval or oblique vein in man) entered on the left side of the pig heart and drained via the coronary sinus. The porcine left atrium received only 2 pulmonary veins, whereas 4 orifices were generally observed in man. The sweep between the inlet and outlet components of the porcine right ventricle was less marked than in man, and a prominent muscular moderator band was situated in a much higher position within the porcine right ventricle compared with that of man. The apical components of both porcine ventricles possessed very coarse trabeculations, much broader than those observed in the human ventricles. In general, aortic-mitral fibrous continuity was reduced in the outlet component of the porcine left ventricle, with approximately two-thirds of the aortic valve being supported by left ventricular musculature. Several potentially significant differences exist between porcine and human hearts. It is important that these differences are considered as the arguments continue concerning the use of transgenic pig hearts for xenotransplantation.

A human polydactylous left foot with 9 toes, amputated from an 11-mo-old child, was examined by x-ray and magnetic resonance imaging and by gross dissection to identify the digits. The normal sequence of toes from medial to lateral is 1, 2, 3, 4, 5. Examination of the morphology of tendons and muscles suggested the toe sequence was 1, 2, 3/4, ?,5, 2, 3/4, 3/4, 5. The 2 toes in the sequence that are underlined were displaced dorsally and were found to have 2 extensor tendons, no flexor tendons and nails that were conical and situated at their tips. These toes resembled those described as ‘double-dorsal’ and which develop in paws of mice in which a gene normally expressed ventrally is functionally inactivated (Loomis et al. 1996). Specification of toe formation occurs in leg buds early in embryonic development and later there is rotation of the limb so that the anterior (rostral) part comes to lie medially, i.e. the hallux which was anterior (rostral) now is on the inner (medial) side of the foot. A disruption in the patterning of this foot in both anteroposterior (rostral-caudal) and dorsoventral axes during development could be responsible.

When the tibialis anterior muscle of the rabbit is progressively stretched during surgical limb distraction, the muscle fibres lengthen by addition of new serial sarcomeres, provided that stretch is carried out at an appropriate rate. However, in spite of the apparent adaptation to the new functional length, range of joint movement is greatly decreased. In this study we have first, made measurements of the passive tension developed by distracted muscles over the range of joint movement and secondly made quantitative measurements of endomysial and perimysial connective tissue content. It was found that at all ankle joint angles greater than 90°, the passive tension developed by the distracted muscles was greater than both contralateral and sham-operated controls. Image analysis showed that the ratio of collagen to contractile material was increased in distracted muscles compared with muscles from sham-operated controls, due to increased deposition of collagen type III. Scanning electron microscopy showed the presence of a dense perimysial weave surrounding the distracted muscle fibres. These quantitative and qualitative changes in the connective tissue component could account for the increased stiffness demonstrated by the physiological measurements. It would seem that in distracted muscle the connective tissue element adapts less readily than the contractile component, with prolonged stretch leading to damage to the perimysial and endomysial network, with subsequent fibrosis and loss of muscle compliance. Such changes could help explain the loss of range of movement noted in the distracted limbs of patients undergoing surgical limb-lengthening and in other conditions that result in muscle contractures.

Tibial torsion, twisting of the tibia about its longitudinal axis, varies during development and early childhood. Knowledge of the normal range of tibial torsion at various ages and its accurate clinical measurement is important in the assessment of the extent of a torsional deformity. To evaluate tibial torsion a reliable technique for its measurement in vivo is therefore required. The aim of this study was to determine which of 4 existing in vivo methods of measuring tibial torsion was the most accurate and had the highest repeatability, by comparing them with direct measurement of the tibia. A wide range of mean values for tibial torsion was observed, using the various techniques, with none of the indirect techniques employed having a strong correlation with direct measurement of tibial torsion. The repeatability of the indirect techniques was observed to be low both in cadavers (n=4) and the living (n=3). Since none of the in vivo techniques appear to measure true tibial torsion or be of a reasonable repeatability, alternative easy to use and inexpensive methods need to be developed. Accurate clinical measurement of tibial torsion is important in the assessment of the extent of a torsional deformity. It is recommended that data gained using the methods reviewed here are interpreted with caution.

Metatarsal growth was studied in 780 human fetal metatarsal bones, crown-rump length ranging from 120 to 260 mm and gestational age ranging from 14 to 23 wk postconception. Total length, diaphyseal length and diameter were measured and statistical analysis performed. Means and standard deviations for each measurement were calculated at 1 wk intervals. These data were correlated with crown-rump length and gestational age and an equation was constructed in an attempt to predict gestational age.

Frank Goldby, Emeritus Professor of Anatomy in the University of London at St Mary's Hospital Medical School (now Imperial College School of Medicine at St Mary's) died at Cambridge on 20 October 1997, aged 94, fully compos mentis as those who knew him would have expected, and content enough to go when he had to, having reached the same age as his father. He became a member of the Anatomical Society of Great Britain and Ireland in 1931, served as Secretary from 1946 to 1956 and as President from 1957 to 1959. He is survived by his wife Helen and 6 children, to whom our deepest sympathy is extended.

Anatomical Society of Great Britain and Ireland

Winter meeting, 5–7 January 1999. This will be held at the University of Leeds and will include a one and a half day symposium on ‘Structure and function of molecular motors’. Further information can be obtained from Dr Roger Soames, Centre for Human Biology, University of Leeds, Leeds LS2 9JT.

Summer meeting, 24–26 July 2000. This will be held at the University of Cambridge.

European Research Conference

Neural Mechanisms of Learning and Memory: Dynamics of the Trace. To be held in Acquafredda di Maratea, Italy, 9–14 May 1998.

Development Biology: The Genetic Control of Morphogenesis. To be held in Lengries, Germany, 6–11 June 1998.

Details may be obtained from Dr J. Hendekovic, URESCO Unit, European Science Foundation, 1 quai Lezay-Marnésia, 67080 Strasbourd Cedex, France. Tel. +33 388 76163; fax +33 388 366987; e-mail [email protected]. Online information and application at: http//www.esforg/euresco