A rare case of unilateral hemifacial spasm and facial palsy associated with an abnormal anatomical variant of the posterior basilar circulation.

Tortuous vertebral arteries are a rare anatomical variant. Mild tortuosity is usually asymptomatic whereas severe tortuosity may present with ischaemic symptoms or compressive symptoms (focal neurological deficit). While a resulting hemifacial spasm has been previously described, sparse literature exists for its association with facial palsy. We present a rare case of facial spasm along with facial palsy in a 67-year-old woman who was found to have an anatomical variant in the posterior basilar circulation with an ectatic basilar artery and significantly displaced posterior vertebral artery impinging on the facial nerve.

Diagnostic utility of freehand core-needle biopsy in head and neck masses.

OBJECTIVE: To review our experience with freehand core-needle biopsy in the assessment of unexplained head and neck masses. METHODS: A total of 770 patients with head and neck masses (referred over a 22-month period) were evaluated. A retrospective chart review was performed on 53 of those patients who underwent core-needle biopsy for an unexplained mass. RESULTS: Correct sampling of the target tissue was achieved in all 53 patients (100 per cent) using a freehand core-needle biopsy technique. The diagnostic accuracy for providing adequate tissue samples for histopathological diagnosis was 96 per cent; the test sensitivity was 92 per cent. Four patients (7 per cent) required open surgical biopsy prior to commencing definitive treatment. CONCLUSION: Out-patient freehand core-needle biopsy can be carried out safely on select patients with head and neck masses, and provides high quality histopathology specimens with high diagnostic utility.

The XMaS beamline at ESRF: instrumental developments and high-resolution diffraction studies.

The beamline, which is situated on a bending magnet at ESRF, comprises a unique combination of instrumentation for high-resolution and magnetic single-crystal diffraction. White-beam operation is possible, as well as focused and unfocused monochromatic modes. In addition to an eleven-axis Huber diffractometer, which facilitates simple operation in both vertical and horizontal scattering geometries, there is an in-vacuum polarization analyser and slit system, mirrors for harmonic rejection, sub 4.2 K and 1 Tesla magnetic field sample environment, plus a diamond phase plate for polarization conditioning. The instrumentation developed specifically for this beamline is described, and its use illustrated by recent scientific results.

Human blood-derived macrophages induce apoptosis in human plaque-derived vascular smooth muscle cells by Fas-ligand/Fas interactions.

Human atherosclerotic plaques that rupture are characterized by relatively low vascular smooth muscle cell (VSMC) and high inflammatory cell contents. Ruptured plaques also contain higher numbers of apoptotic VSMCs than do stable lesions, suggesting that VSMC apoptosis may promote plaque rupture. We examined the ability of human monocytes/macrophages to induce apoptosis of VSMCs derived from human carotid plaque, aortic media, and coronary media. Macrophages, but not T lymphocytes, induced a dose-dependent apoptosis of VSMCs, which required monocyte maturation to macrophages and direct cell-cell contact/proximity. VSMC apoptosis was inhibited by neutralizing antibodies to Fas-ligand (Fas-L) or an Fas-Fc fusion protein, indicating the requirement for membrane-bound Fas and Fas-L. Monocyte maturation was associated with increased surface expression of Fas-L, coincident with the onset of cytotoxicity. VSMCs expressed surface Fas, which was increased in plaque VSMCs, and plaque VSMCs also underwent Fas-induced apoptosis. We conclude that human macrophages potently induce human VSMC apoptosis, which requires direct cell-cell interactions and is in part dependent on Fas/Fas-L interactions. Macrophage-induced VSMC apoptosis may therefore directly promote plaque rupture.

Effects of reserpine on expression of the LDL receptor in liver and on plasma and tissue lipids, low density lipoprotein and fibrinogen in rabbits in vivo.

The effects of administering reserpine (0.1 mg/kg) or 17alpha-ethinyloestradiol (2.5 mg/kg) to New Zealand White rabbits on low density lipoprotein receptors in liver, on plasma low density lipoprotein and fibrinogen and on plasma and tissue lipids were determined. Blood pressure and heart rate were also followed. The drugs were injected subcutaneously into conscious unrestrained rabbits for 5 days. On the 6th day homologous 125I-tyramine cellobiose labelled low density lipoprotein (125I-TC-LDL) was injected intravenously and 24 h later the animals were killed. Compared to controls, reserpine significantly increased LDL receptor expression in the liver by about threefold, and reduced total cholesterol in plasma, aorta and heart, without affecting plasma triglycerides. The reductions in plasma cholesterol and heart were due to decreases in both unesterified and esterified cholesterol. Similar effects were observed with oestrogen, except that there was no change in esterified cholesterol in aorta. In liver, a decrease of 24% in total cholesterol was due mainly to decreased esterified cholesterol. In adrenal glands total cholesterol increased by 25%. Reserpine significantly accelerated the plasma clearance of intravenously injected homologous 125I-TC-LDL and reduced its accumulation in aortic wall. Neither reserpine nor oestradiol affected blood pressure, haematocrit or plasma fibrinogen. The results suggest that reserpine is an affective anti-atherogenic drug capable of decreasing cholesterol in plasma, arteries and heart by increasing high affinity LDL receptors in the liver.

Inhibition of human arterial smooth muscle cell growth by human monocyte/macrophages: a co-culture study.

Monocyte/macrophages produce a variety of substances which may influence the function of smooth muscle cells (SMC). During atherogenesis, macrophages are thought to modulate SMC migration, proliferation and synthesis of extracellular matrix. Such modulation is the balance between stimulatory and inhibitory influences. Thus, for example, our earlier studies have shown that macrophages not only secrete mitogens, but also produce small molecular weight inhibitors of SMC proliferation. In the present study, we have used a co-culture system in which human monocyte/macrophages were separated from human arterial SMC (hSMC) by a filter with the optional addition of a 12 kDa cut-off dialysis membrane, in order to assess their effect on hSMC growth. We have found that human peripheral blood-derived monocytes produced a substance of < 12 kDa that inhibited hSMC growth in the co-culture system. The monocyte-derived factor causing this effect was completely blocked by indomethacin, indicating that growth-inhibitory factors produced by the monocytes were cyclooxygenase products. We have shown that PGE1 and PGE2 inhibit hSMC growth, making them likely candidates for the effector molecules released from monocytes in our co-culture system.

Monocyte prostaglandins inhibit procollagen secretion by human vascular smooth muscle cells: implications for plaque stability.

Extracellular matrix remodelling occurs during atherosclerosis dictating the structure of the plaque and thus the resistance to rupture. Monocytes and macrophages are believed to play a role in this remodelling. In the present study, filter-separated co-culture has been used to study the effect of monocytes on procollagen turnover by human vascular smooth muscle cells (VSMC). In this system, freshly isolated human peripheral blood monocytes inhibited procollagen secretion from VSMC without affecting either degradation of procollagen, or DNA synthesis by the VSMC. Insertion of a 12 kDa dialysis membrane between the two cell types and treatment with indomethacin showed that the inhibitory factor was of low molecular weight and was cyclooxygenase-dependent. Pre-incubation of each cell type with indomethacin demonstrated that monocyte, but not VSMC cyclooxygenase was required. Thus, the inhibitory effect on procollagen secretion was due, most likely, to monocyte prostaglandins. Neither inhibition of thromboxane synthetase, nor blocking IL-1 activity, reduced the inhibitory activity. Addition of prostaglandins PGE1, PGE2 and PGF2alpha to VSMC cultures caused a reduction in procollagen secretion which was equivalent to, but was not additive with, the maximal effect achieved by monocytes. Monocytes and macrophages are a major source of prostaglandins and these molecules are likely to play an important role in collagen turnover within lesions.

C-reactive protein frequently colocalizes with the terminal complement complex in the intima of early atherosclerotic lesions of human coronary arteries.

There is increasing evidence that complement activation may play a role in atherogenesis. Complement proteins have been demonstrated to be present in early atherosclerotic lesions of animals and humans, and cholesterol-induced atherosclerotic lesion formation is reduced in complement-deficient animals. Potential complement activators in atherosclerotic lesions are now a subject matter of debate. C-reactive protein (CRP) is an acute-phase protein that is involved in inflammatory processes in numerous ways. It binds to lipoproteins and activates the complement system via the classic pathway. In this study we have investigated early atherosclerotic lesions of human coronary arteries by means of immunohistochemical staining. We demonstrate here that CRP deposits in the arterial wall in early atherosclerotic lesions with 2 predominant manifestations. First, there is a diffuse rather than a focal deposition in the deep fibroelastic layer and in the fibromuscular layer of the intima adjacent to the media. In this location, CRP frequently colocalizes with the terminal complement complex. Second, the majority of foam cells below the endothelium show positive staining for CRP. In this location, no colocalization with the terminal complement proteins can be observed. Our data suggest that CRP may promote atherosclerotic lesion formation by activating the complement system and being involved in foam cell formation.

Dietary fish oils modify the assembly of VLDL and expression of the LDL receptor in rabbit liver.

Supplementation of the diet of rabbits with fish oil or sunflower oil resulted in significant changes in the lipoproteins and lipids in serum. Compared with chow-fed rabbits, dietary fish oils decreased very low density lipoprotein (VLDL), increased low density lipoprotein (LDL), and shifted the peak of the LDL to denser fractions, whereas sunflower oil increased high density lipoprotein and shifted LDL to the lighter fractions. The amount of LDL receptors in fish oil-fed rabbit liver decreased by > 70% while there was only a small fall in these levels in sunflower oil-fed rabbit liver. The concentrations of apolipoprotein (apo) B in the subcellular organelles of the secretory compartment (rough and smooth endoplasmic reticula and Golgi fractions) were also changed by dietary lipids. In both sunflower oil- and fish oil-fed liver, apo B was increased in the lumen of the rough endoplasmic reticulum compared with fractions from chow-fed rabbit liver. The apo B in the trans-Golgi lumen from fish oil-fed livers was reduced and occurred in particles of d approximately 1.21 g/mL. In contrast, apo B in the trans-Golgi lumen from livers of sunflower oil-fed rabbits was increased and occurred in particles of d < 1.21 g/mL. These results suggests that feeding of fish oils causes an interruption in the intracellular transfer of apo B and hence assembly of VLDL. This leads to an enrichment of the rough endoplasmic reticulum membranes with cholesterol, thus downregulating the expression of the LDL receptor.

European Lipoprotein Club: report of the 20th annual conference, Tutzing, 8-11 September 1997.

The year 1997 celebrated the 20th anniversary of the European Lipoprotein Club. Sessions explored topics in the line of classical concepts and forthcoming advances in the field of basic and clinical research on lipoproteins. Participants from 18 European countries attended the conference. Recent Developments in Lipoprotein Research, were reviewed by Thomas Olivecrona (Umea, Sweden), who gave a perspective on lipolysis; and Gerd Assmann (Münster, Germany), who overviewed epidemiological data of the PROCAM study and focused on the biochemical and genetic components of reverse cholesterol transport. Session I, chaired by Katriina Aalto Setälä (Tampere, Finland) and Marten Hofker (Leiden, Netherlands) was dedicated to 'Lipoprotein receptors (old and new)'. Various structural and functional aspects were reported for the newcomers in the ever enriching LDL receptor gene family (VLDLR, LR7/8B, LR11, Megalin, RAP-related proteins). However, a decade of identification of LDL receptors gene defects reveals now that phenocopies of familial hypercholesterolemia may be linked to a third, yet unknown locus. Identification of pathways which clear HDL is underway. Session II, chaired by David Bowyer (Cambridge, United Kingdom) and Richard W James (Geneva, Switzerland), was entitled 'Significance of lipoprotein heterogeneity (metabolic and pathological aspects)'. Factors involved in lipoprotein modification (dense LDL, oxidation), transient production (post prandial, VLDL synthesis) or degradation (complement activation) and controversial hypotheses on their links with atherosclerosis were discussed. Session III on 'Novel methodologies for lipoprotein research' was chaired by Rudolph Poledne (Prague, Czech Republic) and Armin Steinmetz (Marburg, Germany). Simple technologies for routine assessment of lipoprotein metabolism, as well as the most sophisticated ones, to study lipid and free radical exchanges between particles, were presented.

Magnetism in nickel and synchrotron beam polarization studied by X-ray diffraction.

The ratio of the magnetic to the charge form factors of nickel has been determined by white-beam X-ray diffraction. The measurements were made on the new UK magnetic scattering beamline (XMaS) on a dipole source at the ESRF. The data comprise the three (h,h,0) reflections (4,4,0), (6,6,0) and (8,8,0) and the seven high-order (h,0,0) reflections (6,0,0) to (18,0,0), which doubles the range of wavevectors compared to previous studies. The data have been analysed using Hartree-Fock free-ion wave functions and core electron polarization effects were included. The results support the interpretation of neutron data obtained at lower momentum transfer for the e(g) and t(2g) orbital occupancies. The polarization of the dipole source is deduced to vary from 99.88 to 99.83% between 5 and 15 keV, respectively. This high value makes it an extremely suitable source for studies of ferromagnetism.

Immunohistochemical colocalization of the terminal complex of human complement and smooth muscle cell alpha-actin in early atherosclerotic lesions.

There is substantial evidence that activated components of the complement cascade are present in atherosclerotic lesions, and it was suggested some years ago that smooth muscle cells may be an important target of complement attack by the terminal components of the cascade, C5b-9, also called the membrane attack complex. Recent in vitro studies have shown that assembly of membrane attack complex on smooth muscle cells leads to the release of monocyte chemotactic protein-1, and, if this were to occur in vivo, then it could be responsible for the recruitment of monocytes into the lesion. In this study we have investigated the localization of C5b-9 in early atherosclerotic lesions of human coronary arteries, collected from autopsies, by immunohistochemical staining, C5b-9 was found to colocalize widely with smooth muscle cell alpha-actin, but not with intact macrophages, thus supporting the hypothesis that interaction of complement with smooth muscle cells may indeed be important in atherogenesis.

Processes in atherogenesis: complement activation.

The complement system consists of a complex group of plasma proteins, which, on activation, lead to a cascade of interactions culminating in the production of a variety of pro-inflammatory molecules. The system also contains cellular receptors for complement fragments produced during activation and regulatory molecules. It is part of the innate immune system representing humoral defence, but in certain circumstances may itself contribute to disease. In the formation of atherosclerotic lesions, there are two outstanding cellular phenomena, monocyte recruitment, with subsequent development of lipid-filled foam cells and smooth muscle cell activation. Subendothelial deposition of low density lipoprotein appears to be an important stimulus in these events and substantial evidence suggests that complement activation may be a link between lipoprotein deposition and subsequent lesion development.

Complement-induced release of monocyte chemotactic protein-1 from human smooth muscle cells. A possible initiating event in atherosclerotic lesion formation.

Increasing evidence suggests that complement activation might represent an important mechanism in early atherogenesis. Thus, complement components, in particular the membrane attack complex (MAC) C5b-9(m), have been isolated from human atherosclerotic lesions. Furthermore, complement activation is known to occur in atherosclerotic lesions induced in experimental animals, and the severity of cholesterol-induced plaques is markedly reduced in complement-deficient animals. During atherogenesis monocytes are recruited into the arterial wall, and a potent chemoattractant for monocytes, monocyte chemotactic protein-1 (MCP-1), is expressed by vascular smooth muscle cells (SMCs). We hypothesized that generation of MACs on SMCs during the activation of complement might lead to the release of MCP-1 and hence to monocyte recruitment. In this study, MACs were generated on human SMCs in vitro by sequential addition of the purified complement components C5b6, C7, C8, and C9. This supernatant of the culture was chemotactic for freshly isolated peripheral blood monocytes in a modified Boyden chamber. The chemotactic activity of the supernatant was abolished by anti-MCP-1 blocking antibodies but not by an isotype-matched antibody against an irrelevant antigen. The release of chemotactic activity was dependent on the dose of MAC formed on SMCs and was demonstrated within 10 minutes of exposure of the cells. The data support the hypothesis that complement-mediated release of MCP-1 from SMCs might be important in the recruitment of monocytes into the developing atherosclerotic lesion and could be an important initiating event in atherogenesis.

Measurement of the absolute number of functioning low-density lipoprotein receptors in vivo using a monoclonal antibody.

MAC188 S/S is a monoclonal antibody which can be used in vivo to measure the absolute number of functioning low-density lipoprotein (LDL) receptors in a rabbit. The antibody binds to the extra-cellular domain of the LDL receptor and binding is not blocked by the presence of LDL. When the antibody-receptor complex is internalized, receptor recycling is inhibited for several hours. Thus when saturating doses of MAC188 S/S are administered intravenously, the amount of antibody removed from the blood (minus non-specific removal) is determined solely by the total number of LDL receptors in an animal. In this study MAC188 S/S was used to measure the number of LDL receptors in control rabbits and in animals treated with 17 alpha-ethinyl oestradiol. After treatment (which caused a 47% decrease in plasma cholesterol), receptor-mediated removal of MAC188 S/S from the blood was saturated in both groups following injection of 3.0 mg of antibody per kg body weight. Based on the amount of antibody removed via the LDL receptor at this dose, the total number of accessible LDL receptors was calculated as (2.0 +/- 0.3) x 10(15) receptors per kg body weight in control rabbits and (4.0 +/- 0.4) x 10(15) receptors per kg body weight in oestrogen-treated animals. The number of receptors in various organs was also determined. The monoclonal antibody approach therefore, allows accurate determination of LDL receptor numbers in animals with markedly different concentrations of circulating LDL, conditions in which the use of endogenous ligand would be subject to significant errors.