Impact of the pericapsular nerve group (PENG) block on postoperative analgesia and functional recovery following total hip arthroplasty: a randomised, observer-masked, controlled trial

The pericapsular nerve group (PENG) block is a novel regional anaesthesia technique that aims to provide hip analgesia with preservation of motor function, although evidence is currently lacking. In this single-centre, observer-masked, randomised controlled trial, patients undergoing total hip arthroplasty received pericapsular nerve group block or no block (control group). Primary outcome measure was maximum pain scores (0-10 numeric rating scale) measured in the first 48 h after surgery. Secondary outcomes included postoperative opioid consumption; patient mobilisation assessments; and length of hospital stay. Sixty patients were randomly allocated equally between groups. The maximum pain score of patients receiving the pericapsular nerve group block was significantly lower than in the control group at all time-points, with a median (IQR [range]) of 2.5 (2.0-3.7 [0-7]) vs. 5.5 (5.0-7.0 [2-8]) at 12 h; 3 (2.0-4.0 [0-7]) vs. 6 (5.0-6.0 [2-8]) at 24 h; and 2.0 (2.0-4.0 [0-5]) vs. 3.0 (2.0-4.7 [0-6]) at 48 h; all p < 0.001. Moreover, the pericapsular nerve group showed a significant reduction in opioid consumption, better range of hip motion and shorter time to ambulation. Although no significant difference in hospital length of stay was detected, our results suggest improved postoperative functional recovery following total hip arthroplasty in patients who received pericapsular nerve group block.

Effect of Gaviscon Infant on gastro-oesophageal reflux in infants assessed by combined intraluminal impedance/pH

BACKGROUND

Gaviscon Infant (GI) has been recommended for gastro-oesophageal reflux (GOR) in infants. Its efficacy has not been examined with a physiologically appropriate denominator to define the degree of GOR.

AIM

To investigate the influence of Gaviscon Infant on GOR in infants using combined pH and intraluminal impedance measurement.

METHODS

Twenty infants (mean age 163.5 days, range 34-319 days) exclusively bottle fed, with symptoms clinically suggestive of GOR, underwent 24 hour studies of intra-oesophageal 6 channel impedance and dual channel pH monitoring, during which six random administrations (3+3) of Gaviscon Infant (625 mg in 225 ml milk) or placebo (mannitol and Solvito N, 625 mg in 225 ml milk) were given in a double blind fashion. Impedance/pH reflux data were recorded and analysed blind by one observer.

RESULTS

The median number of reflux events/hour (1.58 v 1.68), acid reflux events/hour (0.26 v 0.43), minimum distal or proximal pH, total acid clearance time per hour (time with pH below pH 4), and total reflux duration per hour were not significantly different after GI than after placebo. Reflux height was marginally lower after GI (median 66.6% v 77.3% oesophageal length) compared with placebo.

CONCLUSIONS

Results showed a marginal but significant difference between Gaviscon Infant and placebo in average reflux height, and raises questions regarding any perceived clinical benefit of its use.

E-cadherin transfection down-regulates the epidermal growth factor receptor and reverses the invasive phenotype of human papilloma virus-transfected keratinocytes

The human papillomavirus type 16 (HPV-16), the type most often associated with cervical cancer, immortalizes primary keratinocytes and inhibits serum/calcium-stimulated differentiation in culture. In this study, we have used a model of keratinocyte immortalization based upon HPV-16 to analyze perturbation of function and expression of E-cadherin, a Ca(2+)-dependent cell-cell adhesion molecule expressed by normal keratinocytes, and its associated proteins. An immortalized keratinocyte cell line generated by cotransfection with HPV-16 E6 and E7 showed decreased membrane E-cadherin expression and redistribution of alpha-, beta-, and gamma-catenin from the undercoat membrane to the cytoplasm. No changes in the level of expression were seen. Selection of the immortalized keratinocyte cell line for resistance to differentiation generated a more transformed cell line with an invasive phenotype, down-regulated E-cadherin and alpha-catenin, and up-regulated the epidermal growth factor receptor (EGFr). Transfection of an E-cadherin expression construct into the differentiation-resistant cell line restored membrane-bound E-cadherin and catenin expression, down-regulated the EGFr, and reversed the invasive phenotype. These results indicate that overexpression of the EGFr correlates with perturbation of the E-cadherin/catenin complex seen in the HPV-16 E6- and E7-transfected keratinocytes and may underlie a functional interaction between growth-regulatory factors and adhesion molecules (E-cadherin/catenin).

A functional model of adult human prostate epithelium. The role of androgens and stroma in architectural organisation and the maintenance of differentiated secretory function

A functional model of adult human prostate epithelium is described. This model shows that stromal cells, but not an androgenic stimuli, are required for architectural organisation of prostate epithelium. Within an organised structure, androgenic stimulation is required for the establishment of secretory epithelial cell morphology and associated function. In the absence of stromal cells but in the presence of androgens architectural organisation and secretory function are lost. Epithelial parenchymal units (organoids) from human prostate tissue were isolated, cultured within a three-dimensional collagen matrix, and xenografted subcutaneously into athymic mouse hosts. The grafted gels were rapidly invaded by host fibroblasts. Epithelial organisation initially disappeared but was re-established concurrently with the stromal cell invasion. In intact male hosts, cuboidal and columnar cells that expressed human prostate-specific secretory markers were found. In castrated male and in female hosts epithelial structures were lined with flattened epithelium with no secretory function. This phenomenon could be reversibly replicated by treating intact male hosts with the anti-androgen Flutamide. Gels containing organoids grafted within 0.45 microns Millipore chambers were not invaded by stromal cells and rapidly lost all epithelial organisation and secretory function. When organoids cocultured with human foreskin fibroblasts were grafted within chambers, structural organisation of the epithelium was supported. These results indicate that both heterologous human fibroblasts and mouse stromal cells are capable of permissively supporting adult human prostate epithelial function.

A nude mouse xenograft model of fetal intestine development and differentiation

This report describes a novel in vivo model of intestinal differentiation. Fourteen day, undifferentiated fetal rat small intestine, stripped of the major part of its mesenchyme, suspended in a type I collagen gel and then xenografted into a nude mouse, undergoes small intestinal morphogenesis and cytodifferentiation. All four major epithelial lineages, namely Paneth, goblet, columnar and endocrine are present. Double-label nonisotopic in situ hybridization, employing biotinylated and digoxigenin-labelled whole rat DNA and whole mouse DNA probes, was performed to distinguish donor cells from host cell types. The outer longitudinal smooth muscle layer, and the major part of the lamina propria, including pericryptal fibroblasts, are of host mouse origin; the inner circular smooth muscle layer is of donor rat origin. Cells of the muscularis propria and lamina propria acquired smooth muscle alpha-actin, presumably under the influence of the donor endoderm. Furthermore, this xenograft develops a host vascular network, and cells with the morphological appearance of lymphocytes are present within the intestinal epithelium. The production of chemotactic factors by the endoderm is postulated because grafting of collagen gel alone results in a minimal invasion by stromal cells which do not express smooth muscle alpha-actin.

Control of differentiation in a rectal adenocarcinoma cell line: the role of diffusable and cell-associated factors

The rectal adenocarcinoma cell line, HRA-19a1.1, was cultured in a three-dimensional type I collagen gel and then xenografted in nu/nu mice to determine whether the in vivo environment could induce further morphological differentiation of the in vitro collagen gel cultures. Three phenotypic changes were observed. Type I collagen induces glandular differentiation in vitro in which well polarized cells are organized around a central lumen, as has been previously reported. Seven days after xenografting this structure in nu/nu mice, the glandular structures appeared to have 'ballooned' forming cyst-like structures lined by a monolayer of flattened cells. There were no stromal cells associated with the graft at this stage, but with time stromal cells invaded the collagen. At points where these cells were closely associated with the HRA-19 cells there was a marked phenotypic change, with the flattened lining cells seen at day 7 becoming columnar. By 21 days the stromal cells had replaced the collagen and the histology of the graft now resembled that of an adenocarcinoma. Placing this cell-collagen culture in a Millipore chamber prior to grafting resulted in cyst-like structures only. Here we provide conclusive evidence that heterologous connective tissue cells can induce differentiation of a rectal adenocarcinoma cell line by a non- or poorly diffusible factor(s). Furthermore, we show that this cell-collagen xenograft method has certain advantages over conventional xenograft methods: notably, a consistent 100 per cent take rate; considerably fewer cells are required to form a tumour; and the time taken to form a tumour is dramatically reduced.

The role of the arginine-glycine-aspartic acid-directed cellular binding to type I collagen and rat mesenchymal cells in colorectal tumour differentiation

The relationship between the adhesion of five human colorectal carcinoma cell lines to extracellular matrix (ECM) proteins, namely type I collagen, type IV collagen, fibronectin, laminin and basement membrane extract (Matrigel), and the ability of these cells to express morphological differentiation when grown in a basement membrane extract (Matrigel) or on normal rat mesenchymal cells has been examined. Two cell lines, SW1222 and HRA-19, organised into glandular structures, with well-defined polarity when cultured on both substrata as well as in three-dimensional (3D) collagen gel culture as previously shown. The remaining three cell lines (SW620, SW480 and HT29) grew as loose aggregates or as they would normally grow on tissue culture plastic. Addition to the culture medium of a hexapeptide, containing the cell-matrix recognition sequence arginine-glycine-aspartic acid (RGD), inhibited attachment and glandular formation of SW1222 and HRA-19 when these cells were grown on living mesenchymal cells, but not in Matrigel. The morphological differentiation of HRA-19 cells in 3D-collagen was also inhibited by the same RGD-containing peptide, as previously shown for SW1222 cells. Attachment of the remaining three cell lines was inhibited on mesenchyme but not in Matrigel, further supporting the specificity of the peptide effect on epithelial-mesenchymal binding. In conclusion we have shown that colorectal tumour cells are able to bind ECM proteins and that the cellular binding is an essential step in the induction of the morphological differentiation seen on living mesenchymal cells, in basement membrane extracts and in type I collagen gel.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary response to free fatty acid intravenous infusion in the rabbit: role of leukotrienes and the effect of prostacyclin

Intravenous infusion of free fatty acid (FFA) 20 mg.kg-1.min-1 produces pulmonary edema, hypoxemia, hyperventilation and increase in the alveolar surfactant content in rabbits in less than 15 min. We tried to study the role of leukotrienes (LT) and the effects of PGI2 in pulmonary response to FFA. We used Piriprost an inhibitor of LT synthesis or Epoprostenol (Prostacyclin: PGI2) in 4 series of rabbits treated with FFA or its vehicle. Piriprost given as an aerosol (0.1% W/W in THAM) scarcely modified the morphofunctional changes induced by FFA. The only pulmonary effect prevented by Piriprost was the increase in surfactant content (disaturated phosphatidylcholine: DSPC) in broncho-alveolar lavage gluid (BAL). PGI2 administered in a dose of 0.1 micrograms.kg-1.min-1 5 minutes prior to a 15 min infusion of FFA was also unable to prevent most of the effects of FFA on the lung. Only the increase in DSPC in BAL was prevented by PGI2. Some animals received a smaller dose of FFA, because they died earlier. Piriprost, as well as PGI2, shortened the survival time of rabbits treated with FFA. This decrease in the survival rate of animals treated with FFA could account for the lack of increase in DSPC post-FFA. Since other morphofunctional changes induced by FFA were scarcely modified by both Piriprost or PGI2, our results suggest that it is unlikely that either leukotrienes on PGI2 may have a significant effect on pulmonary disturbances induced by FFA.

Toxicity of 3-nitronaphthalimides to V79 379A Chinese hamster cells

The cellular uptake and toxicity of a number of substituted 3-nitronaphthalimides was investigated. Uptake of these compounds into cells was initially rapid and reached a plateau after several hours, where in some cases intracellular concentrations were much greater than the corresponding extracellular concentrations. Little uptake was obtained, however, with a compound carrying an acidic substituent. Toxicity studies divided the compounds into two main groups; those where survival curves were convex and those where survival curves were concave. The shapes of survival curves of the latter group did not appear to reflect depletion of extracellular drug. Uptake and toxicity of different drugs were not well correlated and bioreductive metabolism of the nitro-substituent did not appear to be a major contributor to toxicity. There was no consistent differential toxicity of these drugs in aerobic and hypoxic conditions. It was concluded that the nature of the ring substituent had more effect on toxicity than the absolute concentration of the naphthalimide ring or bioreductive metabolism of the nitro-group.