Distribution of type X collagen mRNA in normal and osteoarthritic human cartilage.

The function of collagen X, a unique homotrimer synthesised by hypertrophic chondrocytes, is not known but its localisation and transient expression at sites of calcification suggest that it is likely to be associated with events in the early stages of endochondral bone formation. Osteoarthritis (OA) is a disorder characterised by new bone formation but the role of type X collagen in its pathogenesis is unclear. A 700-bp restriction fragment encoding most of the C-terminal non-collagenous domain and part of the 3'-untranslated region of the human collagen X gene has been used for in situ hybridisation studies on human OA joints removed from hip and knee replacement operations and the results compared with immunohistochemical localisation of type X collagen gene product.

Calcium homeostasis in bovine somatotrophs: calcium oscillations and calcium regulation by growth hormone-releasing hormone and somatostatin.

The free intracellular calcium ion concentration ([Ca2+]i) was measured in single cells of a population containing 65-80% somatotrophs, using the fluorescent Ca(2+)-indicator Fura-2 and digital imaging microscopy. Spontaneous oscillations in [Ca2+]i ranging in frequency up to 1.5 oscillations per minute were observed in 30% of somatotrophs.

Investigation of a quantitative post-hybridization signal amplification system for mRNA-oligodeoxyribonucleotide in situ hybridization.

This study was undertaken to assess a post-hybridization amplification system for increasing the sensitivity of in-situ hybridization with oligodeoxyribonucleotide (oligonucleotide) probes. The technique employs a multilayer streptavidin-biotinylated link protein amplification technique, similar to that used in the ABV histochemical amplification system, to attach increasing numbers of radiolabelled streptavidin molecules to a biotinylated ologonucleotide probe. In tissue sections the amplification technique increases the signal-to-noise ratio dramatically, increasing the sensitivity of in situ hybridization and reducing the autoradiographic exposure time.

Calcium signals in single T cells on activation by lectin.

Succinylation of concanavalin A (Con A) reduces its oligomer size while retaining its mitogenicity, and provides a probe of T cell activation. We have observed responses of cytosolic ionized calcium to succinyl Con A in suspensions of Jurkat and rat lymph node (LN) cells, using a fluorimeter, and in single cells settled on glass, using a dual wavelength video imaging system. In the fluorimeter a mitogenic level of succinyl Con A (30 micrograms/ml) produced only a 15-30 nM rise in average cell calcium in the suspended Jurkat or rat cells whereas the use of quantitative video imaging produced asynchronous 250-1000 nM pulses of free calcium in 35% of Jurkat cells and 300-850 nM pulses in 45% of rat LN cells.

Demonstration of variation in chondrocyte activity in different zones of articular cartilage: an assessment of the value of in-situ hybridization.

Several methods have been described for investigating chondrocyte metabolism in vitro. In this study, in-situ hybridization (ISH) using an oligonucleotide probe (i.e.

Spatial dynamics of intracellular calcium in agonist-stimulated vascular smooth muscle cells.

Vasoconstrictor agonists stimulate smooth muscle contraction by inducing a rise in intracellular free Ca2+. Digital-imaging microscopy of fura-2 fluorescence from single vascular smooth muscle cells cultured from the human internal mammary artery has allowed us to record the subcellular alterations in Ca2+ that occur immediately after stimulation by receptor agonists. The thrombin-induced rise in cytoplasmic free Ca2+ begins in a discrete region typically located close to the end of the cell.

Inositol phospholipid turnover and intracellular Ca2+ responses to thyrotrophin-releasing hormone, gonadotrophin-releasing hormone and arginine vasopressin in pituitary corticotroph and somatotroph adenomas.

We have studied the inositol phospholipid turnover response to thyrotrophin-releasing hormone (TRH) gonadotrophin-releasing hormone (GnRH) and arginine vasopressin (AVP) in five corticotroph and six somatotroph pituitary adenomas. GnRH (100 nM) increased inositol phospholipid turnover in five of five somatotroph adenomas tested by an average of 36.4 +/- 9.

Topographical rearrangement of a plasma membrane antigen during capacitation of rat spermatozoa in vitro.

We have previously described an antigen (termed 2B1) on rat spermatozoa that is present on the plasma membrane overlying the tail domain. The antigen is mobile within the plane of the plasma membrane and a mAb to it blocks fertilization in vitro. In the present study we describe some dynamic properties of this antigen in relation to its topographical distribution.

A gonadotropin-releasing hormone (GnRH) antagonist distinguishes three populations of GnRH analog-responsive cells in human and rat pituitary in vitro and produces an acute increase in intracellular Ca2+ concentration without inducing gonadotropin secretion.

We have examined the actions of the potent GnRH antagonist [N-acetyl-D beta Na11-D-pCl-Phe2-D-Phe3-D-Arg6,Phe7,Arg8-D-Ala10]NH2GnRH++ + (GnRHa) on basal and GnRH-stimulated LH secretion, inositol phospholipid turnover, and intracellular Ca2+ levels in dispersed rat anterior pituitary tissue. As expected, GnRHa was found to be a pure antagonist of secretion, but was paradoxically equipotent with GnRH in stimulating inositol phospholipid turnover. Examination of intracellular Ca2+ changes at the single cell level using digital video-enhanced fluorescence imaging demonstrated that dispersed rat pituitary cells appeared to contain three GnRH analog-responsive cell populations: those that increased intracellular Ca2+ in response to both GnRH and GnRHa, and those that responded to either GnRH or GnRHa only.

Intervertebral foramen venous obstruction. A cause of periradicular fibrosis?

Disc herniation into the intervertebral foramen (IVF) or osteophytic outgrowths from the margins of the apophyseal joints that project into the IVF may compress the neural structures, but in this cadaveric study of 160 lumbar foramens (age range, 35-91 years), the authors have found that they were much more commonly associated with compression and distortion of the large venous plexus within the IVF. In the absence of direct nerve compression (seen in only eight specimens), the most severe neural changes were associated with compression, congestion, and resultant dilatation of foraminal veins. Pathologic changes within and around the nerve root complex included peri- and intraneural fibrosis, edema of nerve roots, and focal demyelination.

Retained surgical swab debris in post-laminectomy arachnoiditis and peridural fibrosis.

We examined soft tissue biopsies from 26 patients with symptomatic nerve root fibrosis and arachnoiditis after a previous laminectomy. Dense fibrous connective tissue was found about the nerve roots and in 14 cases (55%) fibrillar foreign material was seen within it. This material had the histochemical characteristics of cotton fibres from swabs and neurosurgical patties.

The repeat distance of myosin in the thick filaments of various muscles.

The meridional spacing of the X-ray diffraction peak from the repeat of myosin along the thick filament of four muscles has been remeasured on the same apparatus. The frog sartorius gave a shorter repeat distance (143.7 A) than the three invertebrate muscles, which ranged from 144.

Baseline epidemiological studies for a hepatitis B vaccine trial in Kangwane.

Hepatitis B markers were determined by radioimmunoassay of serum samples from 1 495 Black subjects representative of the resident population of Kangwane, a rural area with a high incidence of chronic liver disease and hepatocellular carcinoma. Pregnant women formed an important part of the study group, since it was intended to assess the frequency of perinatal transmission and the passive immunity of their infants, two factors which would markedly influence an infant immunization programme. A high overall marker positivity rate was found, indicating that hepatitis B is endemic.

An evaluation of co-trimoxazole in the treatment of Plasmodium falciparum malaria.

Two dosage schedules of co-trimoxazole, the standard antibacterial and a 2-day high-dose schedule, were compared with a standard course of chloroquine in the treatment of uncomplicated Plasmodium falciparum malaria. Parasites were cleared from the blood at similar rates, but pyrexia responded more slowly following the standard cotrimoxazole dose. No recrudescences were detected in those observed for up to 60 days after treatment.