Osteointegration of bone graft in porous-coated total hip arthroplasty

Since 1983, 19 patients have had bone grafting of acetabular defects in association with a porous-coated acetabular prosthesis. The defects were defined by anatomic location to assess the rates of incorporation at different sites. The average time to incorporation was 12 months, judged by trabecular continuity. Superolateral grafts showed a greater degree of rarefaction than medial grafts. Nonprogressive migration of the graft was seen in only two cases before full incorporation of the graft. Developing lucency was seen up to 2 mm at the prosthesis-graft interface but not at the graft-ilium level. Roentgenograms suggested that integration of porous acetabular prostheses into bone may improve results of reconstructive surgery of the acetabulum.     

An application of capture-recapture methods to the estimation of completeness of cancer registration

Completeness of cancer registration has not been consistently ascertained across different registries. This report describes how capture-recapture methods have been used to estimate completeness at the Ontario Cancer Registry. The method was applied in two fashions; first, using three data sources in a modeling approach: and second, using two data sources and standard, simple capture-recapture methods. The modeling approach is more flexible, since several variables that influence cancer registration can be considered and can be used to identify reporting patterns of different data sources. In the present analysis, estimates of completeness of the registry as a whole were remarkably similar using either two or three data sources, and site-specific comparisons differed by at most 7%. Because of the advantages of capture-recapture methods-estimation of level of completeness, possible comparability of estimates across different registries, and versatility to consider other determinants of cancer registration-a plea for greater use of these methods in cancer registration is made.     

Effects of Increasing Gestation,Cortisol and Maternal Undernutrition on Hypothalamic Neuropeptide Y Expression in the Sheep Fetus

We have characterized the localization and the ontogenetic changes in Neuropeptide tyrosine (NPY) before birth and investigated the regulation of NPY expression by cortisol and undernutrition in the fetal sheep hypothalamus during late gestation. Using immunohistochemistry, we have identified NPY-containing neurons in the infundibular nucleus and the internal layer of the median eminence in fetal hypothalami collected between 110 and 147 days gestation. NPY projections were also present in the paraventricular nucleus (PVN) of fetal hypothalami at all ages between 110 days gestation and term. There was a significant increase in the amount of immunoreactive NPY/g hypothalamus between 87 and 113 days and 131–140 days gestation and a further significant increase after 141 days gestation. The total hypothalamic content of immunoreactive NPY increased significantly between 87 and 113 days and 141–145 days gestation. The levels of NPY mRNA: 18S rRNA in the mediobasal region of the fetal hypothalamus were significantly higher at 145–146 days gestation than at any earlier gestational age between 116 and 141 days gestation. Cortisol (2.5–3.0 mg/24 h) was infused intrafetally between 109 and 116 days gestation. The ratio of NPY mRNA: 18s rRNA in the mediobasal region of the fetal hypothalamus was significantly higher in the cortisol-infused group when compared with the saline-infused control group at 116 days gestation. Maternal, and hence fetal undernutrition, was induced between 110 and 146 days gestation. At 145–146 days gestation the ratio of NPY mRNA: 18S rRNA in the mediobasal region of the fetal hypothalamus was significantly higher in the undernutrition group when compared with control animals. We have therefore demonstrated that NPY is present in the hypothalamus of the sheep fetus before birth and that hypothalamic NPY content and NPY mRNA increase before delivery. We have also found that glucocorticoids and undernutrition stimulate increases in NPY mRNA levels in the hypothalamus before birth.     

The role of Na+/K+ ATPase activity during low flow ischemia in preventing myocardial injury: A 31P, 23Na and 87Rb NMR spectroscopic study

An increase in intracellular Na⁺ during ischaemia has been associated with myocardial injury. In this study, we determined whether inhibition of Na⁺/K⁺ ATPase activity contributes to this increase and whether Na⁺/K⁺ ATPase activity can be maintained by provision of glucose to perfused rat hearts during low flow, 0.5 ml/min, ischemia. We used ³¹P NMR spectroscopy to determine changes in myocardial energetics and intracellular and extracellular volumes. ²³Na NMR spectroscopy, with DyTTHA^3- present as a shift reagent, was used to measure changes in intracellular Na⁺ and ⁸⁷Rb NMR spectroscopy was used to estimate Na⁺/K⁺ ATPase activity from Rb⁺ influx rates, Rb⁺ being an NMR-sensitive congener of K⁺. In hearts provided with 11 mM glucose throughout ischemia, glycolysis continued and ATP was twofold higher than in hearts without glucose. In the glucose-hearts, Rb⁺ influx rate was threefold higher, intracellular Na⁺ was fivefold lower at the end of ischemia and functional recovery during reperfusion was twofold higher. We propose that continuation of glycolysis throughout low flow ischemia allowed maintenance of sufficient Na⁺/K⁺ ATPase activity to prevent the increase in intracellular Na⁺ that would otherwise have led to myocardial injury.     

A complication of peribulbar block in a patient with exophthalmos

A patient with marked exophthalmos secondary to thyroid eye disease presented for tarsorrhaphy and removal of orbital fat. A single superolateral peribulbar injection was performed. After injection of 3.5 ml of local anaesthetic solution, the globe suddenly dislocated anteriorly. This complication has not been described previously. In patients with exophthalmos, general anaesthesia should be considered as the method of choice for ophthalmic procedures.      

Evaluation and audit in a paediatric disability service

Parental and professional responses to questionnaires evaluating a paediatric disability service are reported and the viability of auditing structural, process, and outcome aspects of clinical practice are discussed. Expectations of waiting time to first appointment (met for only 52% of consumers) illustrate structural issues. Process issues are reflected in consumer reactions to outreach work (for example, 94% of parents and 84% of professionals found this supportive). Outcome measures such as consumer satisfaction with the service (76% of consumers reported being 'very satisfied' and 20% 'fairly satisfied') suggest that service aims are being met. Good concurrence of service aims with consumer needs is indicated by parental reasons for referral (for example, 75% for diagnostic help, 73% for a better understanding of the disorder, 88% for practical help), referrers' reasons (for example, 55% for a second diagnostic opinion, 45% due to lack of local expertise), and reports from most other professionals involved with the case that a similar service was not provided locally.     

Pharmacokinetics of xamoterol after intravenous and oral administration to volunteers

Summary The pharmacokinetics of xamoterol, a -adrenoceptor partial agonist under clinical evaluation for the treatment of mild to moderate heart failure, have been studied in 12 healthy male subjects. They received 14 mg i.v. and oral doses of 50 and 200 mg as a tablet and 200 mg as a solution in a 4 way cross-over design.After i.v. dosing the elimination half-life was 7.7 h, the total body clearance was 224 ml·min^–1 and the volume of distribution at steady-state (V_ss) was 48 l. Sixty-two percent of the dose was recovered unchanged in urine. After oral doses, the absolute bioavailability of xamoterol was shown to be 5% irrespective of whether the dose was administered as a tablet or solution. Peak plasma concentrations occurred at about 2 h for the tablet dose and slightly earlier (1.4 h) for the solution. Peak plasma concentration, AUC and urinary recovery of unchanged drug increased in proportion to dose. The apparent elimination half-life after oral doses (16 h) was significantly longer than that observed after an intravenous dose.Despite the low bioavailability, the degree of inter-subject variability of oral bioavailability was small probably indicating that the controlling factor is the hydrophilic nature of the molecule rather than extensive first pass metabolism or poor dissolution of xamoterol from the tablet formulation.     

Isolation of phenotypically and functionally distinct macrophage subpopulations from human bronchoalveolar lavage.

Bronchoalveolar lavage was used to obtain alveolar macrophages (AM) from the lower respiratory tract of healthy normal volunteers. Monoclonal antibody (MoAb) probes specific against macrophage determinants were then applied, in conjunction with density separation techniques, to identify and isolate three relatively homogeneous subpopulations from the AM pool. The MoAbs used, RFD1 and RFD7, have previously been shown to differentiate between "dendritic" cells and mature macrophages, respectively, in normal tissue. In addition to these two phenotypically distinct AM subsets (RFD1+D7- and RFD1-D7+ AM), a third AM subpopulation was isolated, which appeared to express both markers (RFD1+D7+). All three separated macrophage subsets were morphologically similar but exhibited distinct differences in surface receptor expression, enzyme content and physiology. Isolated RFD1+D7- AM (the phenotype of "dendritic" cells) did not adhere to the glass, had weak expression of C3b and FcR1 receptors, low fibronectin content and lysosomal activity; only a small proportion of these cells exhibited phagocytosis. The other two isolated AM subsets adhered to glass, expressed C3b and FcR1 receptors, had high fibronectin and acid phosphatase content, and a large majority exhibited phagocytic capacity; qualitative and quantitative differences in these features existed between the two AM subtypes. Furthermore, a diverse spectrum of hexose monophosphate shunt activity was observed throughout all three AM subpopulations, with the highest activity being recorded in the non-adherent AM. These data support the concept of a dynamic heterogeneity within the AM population. The variation in surface antigen expression and physiological capabilities observed amongst the three isolated AM subsets implies the presence of functionally distinct AM within the human lung, which, during steady-state conditions, may be critically balanced under the influence of stimuli in their local microenvironment. In support, proportional and functional shifts have been witnessed amongst these three AM subpopulations with the advent of disease.     

Maintenance of targeting errors by isthmo-optic axons following the intraocular injection of tetrodotoxin in chick embryos.

We have studied the role of electrical activity in the elimination of axonal targeting errors, which is a normal process in brain development. The experiments were focused on the isthmo-optic nucleus (ION), which, in adults, projects in topographical order on the contralateral retina. During embryogenesis, however, a few isthmo-optic neurons project to the ipsilateral retina, and many project to topographically inappropriate parts of the contralateral one; both kinds of targeting error are known to be eliminated by the deaths of the parent neurons. We injected tetrodotoxin (TTX) intraocularly at embryonic days 13 and 15 and, on the latter, applied a retrograde label to the retina of the same eye. Embryos were fixed at embryonic day 17. In some embryos, the label was a peripherally placed fleck of the carbocyanine dye "diI"; the resulting retrogradely labeled neurons in the contralateral ION were much more widely scattered in the TTX-injected embryos than in controls (errors in topography). In other embryos, the label was a solution of rhodamine-B-isothiocyanate (RITC) injected into the vitreous body; this yielded several ipsilaterally labeled isthmo-optic neurons in the TTX-injected embryos, but virtually none in the controls. The numbers of both kinds of aberrantly projecting neuron approached those previously reported near the beginning of the ION's period of neuronal death. We conclude that electrical activity plays an important role in the elimination of axonal targeting errors in the chick embryo's isthmo-optic system.