The critical region on the human Xq

Summary Adult female carriers of balanced X; autosome translocations (118 cases) and of balanced X inversions (31 cases) have been collected from the literature. Forty-five of the 118 translocation carriers in whom the break was in the critical region (Xq13–q22, Xq22–q26, separated by a narrow region within Xq22) showed gonadal dysgenesis. Seven of the 31 inversion carriers in whom the break was in the same region also had gonadal dysgenesis, whereas the remaining 24 were normal in this respect. The critical region consists mainly of Q-bright material, and is the fifth brightest segment in the human genome. The region contains relatively few genes. It is possible that meiotic crossing-over, rarely, if ever, takes place in it. The critical region may therefore consist of two supergenes whose integrity must be maintained to allow normal ovarian development. The effect exerted by this region differs from other known position effects, in that it is independent of the break-point within the region and of the chromosome bands to which the broken ends are attached. One possible mechanism causing this effect might be a change in the replication order of the chromosome bands, which, in turn, might affect their function.     

Arboreality and bipedality in the Hadar hominids

Numerous studies of the locomotor skeleton of the Hadar hominids have revealed traits indicative of both arboreal climbing/suspension and terrestrial bipedalism. These earliest known hominids must have devoted part of their activities to feeding, sleeping and/or predator avoidance in trees, while also spending time on the ground where they moved bipedally. In this paper we offer new data on phalangeal length and curvature, morphology of the tarsus and metatarsophalangeal joints, and body proportions that further strengthen the argument for arboreality in the Hadar hominids. We also provide additional evidence on limb and pedal proportions and on the functional anatomy of the hip, knee and foot, indicating that the bipedality practiced at Hadar differed from that of modern humans. Consideration of the ecology at Hadar, in conjunction with modern primate models, supports the notion of arboredality in these earliest australopithecines. We speculate that selection for terrestrial bipedality may have intensified through the Plio-Pleistocene as forests and woodland patches shrunk and the need arose to move increasingly longer distances on the ground. Only with Homo erectus might body size, culture and other factors have combined to 'release' hominids from their dependence on trees.     

Some Acridine-Resistant Mutations of Bacteriophage T4d

Three new 9-aminoacridine (9AA) resistant mutations of bacteriophage T4D have been isolated and characterized. Two of the mutations, rs and rc, have identical patterns of acridine resistance, but they map on opposite sides of the rII region. In addition, rs has an effect on the plaque morphology of r mutations, whereas rc does not. The third mutation, ama, maps very close to rs but exhibits a different pattern of resistance to 9AA. None of the three is resistant to acridines by virtue of reduced permeability. Taken together with other mutations that have been previously characterized, these new mutations permit us to set the minimum number of acridine-sensitive processes in T4 development at four.     

A Mutant of E. COLI That Restricts Growth of Bacteriophage T4 at Elevated Temperatures

After nitrosoguanidine mutagenesis, a Phage Host Defective (phd) mutant of E. coli HfrH was isolated that supported the growth of T4D wild-type bacteriophage at 30°, but not at 40° or higher. Eleven independent spontaneous mutants of T4 (go mutants) were isolated that overcame the growth restriction at high temperature. All of these mutants were located within three percent recombination of a gene 39 amber mutation in the clockwise direction on the standard map. In mixed infections, the representative go mutant chosen for further study seems to be recessive to its wild-type allele. Temperature-shift experiments suggested that the mutated host function involved in phage growth is a "late" function, beginning in mid-eclipse.—Electrophoresis of phage proteins labelled early and late in infection showed that under restrictive conditions early protein synthesis was normal, but that certain late proteins were absent. However, measurements of DNA synthesis showed that under restrictive conditions the amount of phage DNA synthesized, and especially the amount of DNA sedimenting as high molecular weight replicative intermediate, was reduced. Pulse-chase experiments showed that the phage DNA made under restrictive conditions was not rapidly degraded.     

Electromyography of the gluteal muscles in Hylobates,Pongo, and pan: Implications for the evolution of hominid bipedality

The gluteal musculature of primates has been a focus of great research interest among those who study human evolution. Most current theorists agree that gluteus superficialis (= maximus) need not have changed its action in the step from pongid to hominid, but dispute has arisen over a purported change in action and role of the gluteus medius. To clarify the functions of gluteus medius, gluteus superficialis, and tensor fasciae femoris during ape locomotion, we conducted a telemetered electromyographic study of these muscles in two gibbons, one orangutan, and four chimpanzees as they walked bipedally on the ground and on a horizontal tree trunk, walked quadrupedally on the same substrates, and climbed a vertical tree trunk. The results indicate that the gluteus medius of apes is not, as has been previously suggested, primarily an extensor of the thigh; its action is chiefly that of medial rotation. The role of the gluteus medius during bipedality is the same in apes and humans–to provide side-to-side balance of the trunk at the hip. The change in the hominid lateral balance mechanism can be viewed as primarily osteological, allowing preservation of the same muscle function with an extended thigh. As a result, the stride length is increased and there occurs a diminution of the demands placed on other muscles to maintain anteroposterior balance at the hip and knee. Our data also support the view that vertical climbing may be specifically preadaptive to bipedalism. One may picture the earliest hominid as part biped, when on the ground traveling between scattered food trees, and part climber, when moving from the ground to food.     

Preliminary observations on the feeding behavior ofPan paniscus in the lomako forest of central Zaïre

The feeding behavior and ecology ofPan paniscus was studied over a seven-month period in Equateur, Republic of Zaïre, during 1974–1975. Additional data were gathered during four weeks in 1979.Pan paniscus was found to be primarily frugivorous but bonobo foods also consist of leaves, flowers, pith, invertebrates and small mammals.     

Role of ultrasonography in diagnosing early rheumatoid arthritis and remission of rheumatoid arthritis - a systematic review of the literature

Introduction

Ultrasonography (US) might have an added value to clinical examination in diagnosing early rheumatoid arthritis (RA) and assessing remission of RA. We aimed to clarify the added value of US in RA in these situations performing a systematic review.

Methods

A systematic literature search was performed for RA, US, diagnosis and remission. Methodological quality was assessed; the wide variability in the design of studies prohibited pooling of results.

Results

Six papers on the added value of US diagnosing early RA were found, in which at least bilateral metacarpophalangeal (MCP), wrists and metatarsophalangeal (MTP) joints were scanned. Compared to clinical examination, US was superior with regard to detecting synovitis and predicting progression to persistent arthritis or RA. Eleven papers on assessing remission were identified, in which at least the wrist and the MCP joints of the dominant hand were scanned. Often US detected inflammation in patients clinically in remission, irrespective of the remission criteria used. Power Doppler signs of synovitis predicted X-ray progression and future flare in patients clinically in remission.

Conclusions

US appears to have added value to clinical examination for diagnosing of RA when scanning at least MCP, wrist and MTP joints, and, when evaluating remission of RA, scanning at least wrist and MCP joints of the dominant hand. For both purposes primarily power Doppler US might be used since its results are less equivocal than those of greyscale US.     

Oreopithecus bambolii: an unlikely case of hominid-like grip capability in a Miocene ape

Oreopithecus bambolii, an ape from the late Miocene of Italy, is said to possess a hand capable of a precision grip like that of humans. Relative hand length, proportions of the thumb, and morphological features of the thumb and wrist were adduced to support the idea that Oreopithecus had a hand that closely matched the pattern in Australopithecus. A reappraisal of earlier arguments and comparisons of Oreopithecus with humans, apes, and Old World monkeys, reveals that Oreopithecus had an essentially ape-like hand that emphasized ape-like power grasping over human-like precision grasping.     

Quantitative Locomotion Study of Freely Swimming Micro-organisms Using Laser Diffraction

Soil and aquatic microscopic organisms live and behave in a complex three-dimensional environment. Most studies of microscopic organism behavior, in contrast, have been conducted using microscope-based approaches, which limit the movement and behavior to a narrow, nearly two-dimensional focal field.¹ We present a novel analytical approach that provides real-time analysis of freely swimming C. elegans in a cuvette without dependence on microscope-based equipment. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light through the cuvette. We measure oscillation frequencies for freely swimming nematodes.Analysis of the far-field diffraction patterns reveals clues about the waveforms of the nematodes. Diffraction is the process of light bending around an object. In this case light is diffracted by the organisms. The light waves interfere and can form a diffraction pattern. A far-field, or Fraunhofer, diffraction pattern is formed if the screen-to-object distance is much larger than the diffracting object. In this case, the diffraction pattern can be calculated (modeled) using a Fourier transform.²C. elegans are free-living soil-dwelling nematodes that navigate in three dimensions. They move both on a solid matrix like soil or agar in a sinusoidal locomotory pattern called crawling and in liquid in a different pattern called swimming.³ The roles played by sensory information provided by mechanosensory, chemosensory, and thermosensory cells that govern plastic changes in locomotory patterns and switches in patterns are only beginning to be elucidated.⁴ We describe an optical approach to measuring nematode locomotion in three dimensions that does not require a microscope and will enable us to begin to explore the complexities of nematode locomotion under different conditions.