Book reviews

Myointima formation or intimal hyperplasia is a major undesirable problem at the anastomotic ends of narrow bore arterial autografts and in other arterial wall injuries, which often leads to late restenosis and thrombosis and whose pathogenesis is still not understood. Platelets are suspected to intervene at some stages of its development, together with endothelial and muscle cells, the extracellular matrix and, most probably, adhesion receptors. To ascertain whether and at what stage beta 3 integrins are involved, a rat arterial autograft model was used, together with monoclonal antibody P37, which is directed to the sequence 101-109 of the beta 3 subunit of the human platelet fibrinogen receptor integrin alpha IIb beta 3 and inhibits platelet aggregation in vitro and acute thrombosis in vivo . Three groups of animals were used: group I underwent an arterial autograft of a 5-mm segment of the right common iliac artery; group II received, intravenously, a single dose 0.8 mg kg of P37 at 15 min before the graft implantation; and group III was treated as group II but a similar dose of antibody was additionally given on day 14 after the operation. Animals in each group were sacrificed on days 7, 14, 21, 30 and 50 after the operation, and the grafts were removed for light and electron microscopy observation and further time-dependent morphometric analysis. By day 14, group I autografts already showed intimal hyperplasia and secretory smooth muscle cells, while group II and II autografts presented only some degenerative changes in the medial layer, with no signs of hyperplasia. Intimal hyperplasia was observed on day 21 in group II and on day 30 in group III, although less pronounced than in the corresponding controls. However, by day 50, the three groups had the same thickness of myointima. The immunohistochemical determination of metalloproteases suggests no role for these enzymes in the immunoinhibition of myointima formation. We conclude that P37 inhibits the onset of the intimal hyperplasia in the arterial autografts and that this onset in treated animals seems to be related to the decay of the circulating antibody. Further work is required to decide whether a higher or longer presence of circulating P37 can definitively prevent the development of intimal hyperplasia, as well as to ascertain which cells and which beta 3 integrin receptors intervene.     

Glycans of the trabecular meshwork in primary open angle glaucoma.

AIMS: Glycan expression was compared in glaucomatous trabecular meshwork (TM) and normal TM in order to determine any differences which may reflect pathological changes underlying primary open angle glaucoma (POAG). METHODS: Resin embedded TM from trabeculectomy specimens from 15 eyes with POAG and from 12 eyes with normal anterior segments were probed with a panel of biotinylated lectins and an avidin-peroxidase revealing system at the light microscope level. Statistical analyses were performed on the comparative staining results. RESULTS: The lectins ConA and ePHA showed strong staining in all areas of both glaucomatous and normal TM; ePHA staining of Schlemm's canal (SC) from POAG TM was significantly less than that from normal TM (ePHA-SC p = 0.04). The lectins PSA, LCA, and SNA bound moderately strongly to SC endothelium and weakly to the endothelium of the corneoscleral meshwork (CSM); glaucomatous SC endothelial binding was significantly less than that of normal SC endothelium for PSA and LCA (PSA-SC p = 0.002, LCA-SC p = 0.002). STA and DSA showed moderately strong binding while WGA, ECA, AHA, and MPA bound weakly throughout the TM; for DSA and MPA this staining was significantly greater in POAG than in normal TM (DSA-SC p = 0.001, DSA-CSM p = 0.002, MPA-SC p = 0.01, MPA-CSM p = 0.02). Jac stained strongly throughout the TM and showed no significant difference in POAG compared with normal TM (Jac-SC p = 0.6, Jac-CSM p = 1). 1PHA, SBA, DBA, CTA, UEA-1 and LTA did not bind to glaucomatous TM or normal TM. There were no age-related changes seen. CONCLUSIONS: The expression of some complex and hybrid, bisected and non-bisected N-linked glycans is significantly diminished in glaucomatous TM compared with normal TM. Some glycans with multiple N-acetylglucosamine residues and O-linked glycans with terminal and subterminal galactosyl groups are significantly increased in POAG TM. Glycan expression does not change significantly with age in POAG or normal TM.     

Effects on plasma insulin of intermittent infusions of propionic acid, glucose or casein into the alimentary tract of non-lactating cows maintained on a liquid diet

1. An experiment was conducted using three non-lactating cows completely maintained by infusions of volatile fatty acids into the rumen, and casein into the abomasum. Plasma insulin responses to propionic acid, glucose or casein were recorded. Further information was obtained using protein-free infusions. 2. When part of the propionic acid was infused into the rumen in a twice-daily 3 h dose and the remainder infused continuously with acetic and butyric acids and casein, there were large increases in the concentrations of propionic acid and insulin in the jugular blood. When glucose, corresponding in energy to that supplied by the intermittent propionic acid infusions was similarly infused, the plasma levels of glucose and insulin were increased. Glucose appeared to stimulate a greater increase in insulin than did propionic acid. Casein infused into the abomasum in intermittent doses produced a rise in plasma insulin, but smaller than that observed with propionic acid or with glucose. 3. The protein-free infusion was characterized by a lower concentration of insulin in the blood plasma, a reduction in plasma urea and free amino nitrogen and unchanged plasma glucose.     

Self-ratings by phobic patients during dental treatment: Greater improvement with nitrous oxide than midazolam

The efficacy of intravenous midazolam and nitrous oxide inhalation at reducing self-rated mood and bodily symptoms was compared in patients referred to a dental sedation unit because their dental fears precluded treatment undrugged. Fifty-eight per cent of our patients could be randomly allocated to drug treatment, the others were assigned on clinical grounds. When they arrived for their first treatment, the clinically allocated patients (n = 40) were significantly more anxious, tense and restless than those randomly allocated (n = 61). Both drugs reduced ratings of anxious, tense, discontented and restlessness, but the improvements were greater with nitrous oxide. Nitrous oxide reduced ratings of irritable and depressed, but patients treated with midazolam only showed reductions when dental treatment was finished. The scores for 70 patients were analysed over two treatment days; their pre-sedation scores of tense, depressed and discontented were lower on day 2 than on day 1, with the randomly allocated group showing greater reduction. Nitrous oxide remained superior on day 2. Thirty-eight patients completed 3 days of treatment; there were no further reductions in baseline ratings and the superiority of nitrous oxide was maintained.     

Urea Kinetic Modeling: Comparing the Options

Abstract: In this study 6 commercially produced kinetic modeling packages utilizing a variable volume, single pool urea model, as well as formulae to determine the delivery of therapy, have been compared by applying to each the same set of rigorously collected data for a group of 12 patients. Comparison of the kinetically derived parameters (urea generation rate [ G ], urea distribution volume [ V ], delivery of therapy [ Kt/V ], and normalized protein catabolic rate [ nPCR] ) showed that the values obtained for both G and V differed between packages owing to the numerical methods and the clearance used in the solution of the differential equations. Although a broad agreement between the values established for Kt/V and nPCR was noted, the 95% limits of agreement indicated that it would be prudent to exercise caution when comparing results established by different modeling packages.     

The pathology of "sheep-associated" malignant catarrhal fever in the hamster

Lesions induced in hamsters by inoculation with the "sheep-associated" agents of malignant catarrhal fever (SA-MCF) isolated from a red deer (Cervus elaphus), designated D/1 and of bovine origin (C/2), are described. Clinical signs in hamsters inoculated with the D/1 isolate occurred as early as 13 days after infection although the mean incubation period in animals that developed signs was 27 days. Increased numbers of polymorphonuclear leucocytes were present in the blood of clinically affected hamsters. Gross lesions included erosions of epithelium in the buccal cavity, haemorrhage of the forestomach, dilated fluid-filled intestines and enlargement of the mesenteric lymph node. Microscopic lesions were widespread throughout the body but had a predilection for epithelial surfaces. They consisted of hyperplasia of certain lymph nodes, vasculitis and interstitial accumulations of mononuclear cells of lymphoid appearance in non-lymphoid tissues. Cytolysis was also seen. Lesions produced by the C/2 isolate were similar and both isolates produced disease comparable with that seen in naturally occurring cases in cattle and deer. It is suggested that disease might arise through a dysfunction of the immune system following infection of host large granular lymphocytes by the SA-MCF agent, in a way similar to that suggested for the rabbit.