Lymphoma of the cervix. Imaging and transcatheter arterial embolization

A case of uterine cervix lymphoma with selective embolization after angiography is described. Chemotherapy and radiotherapy were carried out and surgery was avoided.

Left ventricular diastolic function is related to glucose in a middle-aged population

OBJECTIVES

To examine the relation between left ventricular (LV) diastolic function and glucose metabolism in individuals without previously diagnosed diabetes mellitus.

DESIGN

A cross-sectional population-based study.

SETTING

A university hospital.

SUBJECTS

Thirty-five men and women 56-58 years of age without previously diagnosed diabetes or heart disease.

MAIN OUTCOME MEASURES

Left ventricular diastolic function assessed by pulsed Doppler tissue imaging and its relation to fasting plasma glucose, glucose postload and glycated haemoglobin. LV diastolic function was determined by measuring early diastolic filling peak velocity (Em wave cm s-1), late diastolic filling peak velocity (Am wave cm s-1) and their ratio Em/Am.

RESULTS

Peak Em velocity, peak Am velocity and their ratio Em/Am correlated with fasting plasma glucose (r=-0.42, P=0.01; r=0.47, P=0.04 and r=-0.53, P=0.001, respectively). There was a correlation between peak Em velocity, the ratio of Em/Am and glycated haemoglobin. LV diastolic function was also related to glucose postload.

CONCLUSIONS

Left ventricular diastolic function is related to concentrations of fasting plasma glucose, glucose postload and glycated haemoglobin even below the threshold of diabetes. This indicates that glucose concentrations already in the upper end of the normal range has negative impact on cardiac function.

Endoscopic surveillance of columnar-lined esophagus: frequency of intestinal metaplasia detection and impact of antireflux surgery

OBJECTIVE

To quantify the occurrence of intestinal metaplasia in columnar-lined esophagus (CLE) during endoscopic surveillance and to evaluate the impact of antireflux surgery on the development of intestinal metaplasia.

SUMMARY BACKGROUND DATA

The malignant potential in segments of CLE is mainly restricted to those containing intestinal metaplasia. Patients with segments of CLE in which no intestinal metaplasia can be detected are rarely enrolled in a surveillance program but may still be at increased risk of developing esophageal adenocarcinoma because intestinal metaplasia may be missed or may develop with time.

METHODS

The occurrence of intestinal metaplasia on biopsy samples was determined on repeated endoscopies in 177 patients enrolled in a surveillance program for CLE. The incidence of intestinal metaplasia in patients with no evidence of intestinal metaplasia on the two first endoscopies was evaluated on the subsequent endoscopies and compared in patients with medically and surgically treated gastroesophageal reflux disease.

RESULTS

Intestinal metaplasia was found in 53% of the patients (94/177) on their first surveillance endoscopy and was more prevalent in long segments of CLE. The prevalence of intestinal metaplasia increased markedly with increasing number of surveillance endoscopies. Intestinal metaplasia tended to be detected early in patients with long segments of CLE; in patients with shorter segments, intestinal metaplasia was also detected late in the course of endoscopic surveillance. Patients with surgically treated reflux disease were 10.3 times less likely to develop intestinal metaplasia compared with a group receiving standard medical therapy.

CONCLUSION

Biopsy samples from a single endoscopy, despite an adequate biopsy protocol, are insufficient to rule out the presence of intestinal metaplasia. Patients in whom biopsy specimens from a segment of CLE show no intestinal metaplasia have a significant risk of having undetected intestinal metaplasia or of developing intestinal metaplasia with time. Sampling error is probably the reason for the absence of intestinal metaplasia in segments of CLE longer than 4 cm, whereas development of intestinal metaplasia is common in patients with shorter segments of CLE. Antireflux surgery protects against the development of intestinal metaplasia, possibly by better control of reflux of gastric contents.

Allergic reactions at repeat femoral angiography with ioxaglate

PURPOSE

To study the occurrence of allergy-like reactions at angiography, repeated several times, and, secondly, to evaluate the effect of prophylactic treatment in individuals who had earlier experienced such reactions.

MATERIAL AND METHODS

One hundred and fifty-seven patients with hypercholesterolaemia, participating in the Probucol Quantitative Regression Swedish Trial (PQRST), underwent aortofemoral angiography with ioxaglate (Hexabrix) repeated annually for 3 years. Allergic reactions to the contrast medium were recorded. At the following angiographies, all patients who had earlier experienced such reactions were treated prophylactically with steroids and antihistamine.

RESULTS

Allergic reactions were observed in 35 patients. Twelve reacted only year 0, 3 only year 1, 5 only year 2 and 6 only year 3. Eight patients had at least one reaction also when treated prophylactically. It was significantly (p<0.05) more common to react at year 0 but not at year 1 than to react at year 1 but not at year 0. At years 1, 2 and 3 the frequency of reactions was significantly greater in the group given prophylactic treatment than in the group without any earlier reaction at all: 8/20 versus 3/137, 4/23 versus 6/134, and 6/29 versus 6/128, respectively.

CONCLUSION

Some individuals had an increased risk of an allergy-like reaction to the contrast agent. Prophylactic treatment reduced the risk of renewed reactions, but not to the same level as for those without earlier reaction. Nevertheless, individuals who have had earlier reactions can be investigated in the future, with prophylactic treatment.

Artificial surfactants based on analogues of SP-B and SP-C

The hydrophobic proteins SP-B and SP-C are important components of natural surfactant preparations currently used in clinical practice, and physiologically active surfactants can be made from isolated SP-B and/or SP-C reconstituted with synthetic lipids. Efforts have been made to produce these polypeptides, or analogues with similarfunction, by organic synthesis or expression in heterologous systems. It is important to obtain proper folding of the synthetic peptides, as required for optimal interaction with the surfactant lipids. Another issue is to avoid loss of SP-C activity due to alpha-helix to beta-sheet transition. This latter problem can be circumvented by replacing the polyvaline stretch of SP-C with a polyleucine stretch containing a few lysines. Palmitoylation of cysteines or serines at positions 5 and 6 also seems important for the properties of SP-C. SP-B, which is too big a molecule to be easily produced by organic synthesis. apparently can be replaced in an artificial surfactant by a peptide capable of cross-linking phospholipid bilayers. The development of synthetic analogues of the surfacant proteins might make it possible to tailor artificial surfactants for specific therapeutic missions, for instance by enhancing resistance to inactivation by meconium, plasma proteins, or oxygen radicals or maximizing bacteriostatic effects.

Prospects for a new synthetic surfactant

Physiologically active artificial surfactants can be made from lipids and analogs of SP-C and SP-B, the latter serving as cross-linking peptides promoting the formation of a surface-associated surfactant reservoir. Artificial surfactants can probably be tailored to maximize resistance to inactivation by meconium and plasma proteins by modifying the amino acid sequence of the protein analogs or adding non-ionic polymers to the final product. Comparative clinical trials are required to evaluate the efficacy of these new artificial surfactants in various forms of neonatal lung disease.

Resin-bonded bridges by dental undergraduates: three-year follow-up

This study was conducted to evaluate performance and longevity of resin-bonded bridges in patients treated by undergraduate dental students. A total of 62 bridges had been constructed for 53 patients by the students at the School of Dentistry, Karolinska Institute, between 1989 and 1997. After a mean observation period of 35.3 months retention had been lost in 13.6% of 59 bridges examined (4.6% per year). The debonding rate was greater in the mandible (8.3 %/year) than in the maxilla (2.7 %/year), and greatest in the mandibular anterior region (13.4%). Thirty-nine patients with 46 bridges (27 maxillary and 19 mandibular bridges), underwent more detailed clinical examination. No significant differences in bleeding and pocket depth were found between abutment teeth and controls. Bleeding was more frequent at the approximal than the lingual surfaces of the abutment teeth. A questionnaire revealed high patient satisfaction, the resin-bonded bridges meeting their expectations. The study suggests that resin-bonded bridges are an acceptable alternative to conventional bridges. Successful outcome is dependent on stringent case selection, an abutment preparation designed to establish retention form, and meticulous bonding procedures.

Membrane properties and amyloid fibril formation of lung surfactant protein C

Pulmonary surfactant is essential for respiration and lung host defence and is composed of 80-90% lipids, mainly dipalmitoylphosphatidylcholine (DPPC). Surfactant protein C (SP-C) constitutes 1-2% of the surfactant mass, and is one of the most hydrophobic peptides yet isolated. SP-C residues 9-34 form an alpha-helix with a central poly-valine segment, which perfectly matches the thickness of a fluid DPPC bilayer. The palmitoyl groups linked to Cys-5 and Cys-6 of SP-C increase the capacity of the peptide to promote lipid adsorption at an air/liquid interface, and augment the mechanical stability of SP-C/lipid mixtures. SP-C undergoes alpha-helix-->beta-sheet transition and forms amyloid fibrils. NMR and MS studies show that the poly-valine helix is kinetically stabilized, and that once it unfolds, formation of beta-sheet aggregates is significantly faster than refolding. alpha-Helix unfolding is accelerated after removal of the palmitoyl groups. Secondary structure prediction of SP-C yields beta-strand conformation of the poly-valine part. A database search revealed similar discordance between experimentally determined helices and predicted beta-strands for other amyloid-forming proteins, including the prion protein associated with spongiform encephalopathies, and the amyloid-beta (Abeta) peptide associated with Alzheimer's disease. For Abeta and SP-C, removal of the helix/strand discordance by residue replacements abrogates fibril formation in vitro.

The palmitoyl groups of lung surfactant protein C reduce unfolding into a fibrillogenic intermediate

Lung surfactant protein C (SP-C) is a lipophilic peptide that converts from a monomeric alpha-helical state into beta-sheet conformation and forms amyloid fibrils, a process which appears to be accelerated by removal of its two S-palmitoyl groups, and elevated amounts of non-palmitoylated SP-C are found in pulmonary alveolar proteinosis. Here, we used mass spectrometry to study the first step in fibrillogenesis of di-, mono- and non-palmitoylated SP-C. First, the individual decreases in concentration of monomeric alpha-helical forms of the three peptides in an acidified aqueous organic solvent mixture were monitored by electrospray (ES) mass spectrometry. Dipalmitoylated SP-C disappeared with a first-order rate constant of 0.01 h(-1), corresponding to a t(1/2) of 70 hours, while SP-C missing one or two palmitoyl groups disappeared with a rate constant of 0.02 h(-1), t(1/2)=35 hours. This supports the suggestion that the acyl chains stabilise helical SP-C, and that small differences in helix stability can influence fibril formation. The rates of disappearance of the monomeric alpha-helical peptides are much faster than the disappearance of total soluble SP-C (t(1/2)=15 days for SP-C forms soluble after centrifugation at 20,000 g), which suggests that fibril formation is preceded by formation of soluble aggregates. Next, we used matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry to measure hydrogen-->deuterium (H/(2)H) exchange in di-, mono- and non-palmitoylated SP-C in acidified aqueous organic solvents. All three species contain a rigid alpha-helix in their monomeric forms and no difference in deuterium uptake between SP-C with and without palmitoyl groups could be detected. The decreased stability of mono- and non-palmitoylated SP-C observed by ES mass spectrometry is thus not associated with partial unwinding of the helix in solution. Finally, SP-C was shown to unfold during the ES process (where ions are transferred from the solution to the gas phase) and the unfolded forms of di-, mono- and non-palmitoylated SP-C undergo H/(2)H exchange. This, together with the findings from MALDI H/(2)H experiments that the alpha-helix does not exchange, indicates that no partly helical intermediates exist and that the unfolding is highly cooperative.

Gender difference in age-related changes in vascular function

PURPOSE

We investigated whether, in a randomly selected population of 55-year-old men and women, there is a relationship between vascular function measured as flow-mediated (endothelium-dependent) and nitroglycerine-mediated (nonendothelium-dependent) dilatation of the brachial artery and conventional risk factors for cardiovascular disease such as gender, smoking, elevated blood-lipids and high blood pressure. The results are compared with those in a young healthy population of 35-year-olds.

SUBJECTS

A total of 57 men (73% of the invited males) living in the community and 47 women (62% of the invited females) participated and were compared with a previously studied 35-year-old population (52 men and 56 women).

METHODS

Basal brachial artery diameter was measured by high-frequency ultrasound methods. Endothelial function was measured as flow-mediated dilatation (FMD) in response to reactive hyperaemia. The nonendothelium-dependent vasodilatation was measured after administering sublingual nitroglycerine (NTG).

RESULTS

Flow-mediated endothelium-dependent dilatation was similar in men and women being 3.1 +/- 2.5% (mean +/- SD) in men vs. 2.6 +/- 2.3% in women. FMD of the brachial artery was negatively correlated with vessel size in both men and women (P < 0.001). Men had larger brachial artery diameter than women (4.6 +/- 0.7 vs. 3.6 +/- 0.4 mm, P < 0.001). There was no difference in FMD or in NTG-induced dilatation in the women receiving oral oestrogen replacement therapy compared with those that did not. The women taking oral oestrogen had lower cholesterol than those not taking oral oestrogen (P=0.04). FMD was not correlated with any of the risk factors. NTG-induced vasodilatation was correlated with the body mass index (BMI) in men (P=0.01) and a combined risk factor score in women (P=0.04). There was a large increase in the number of subjects with cardiovascular risk factors in the 55-year-old men and women compared with the 35-year-olds. The distribution of risk factors was fairly equal amongst men and women.

CONCLUSION

There are no correlations between any of the conventional cardiovascular risk factors and FMD in a population of 55-year-olds, but there is a high prevalence of risk factors in the 55-year-old age group. NTG-induced vasodilatation correlated with the BMI in men and a combined risk-factor score in women. FMD-induced vasodilatation is smaller in women at 55 years of age than at 35 years of age. FMD was similar in men at 35 and 55 years of age and in men and women at 55 years of age. The smaller FMD in women at 55 years of age, compared with at 35, could be due to postmenopausal hormonal changes.

Morbidity of 10 110 hysterectomies by type of approach

BACKGROUND

Since the late 1980s, the option of laparoscopic hysterectomy has raised questions about the most suitable approach to hysterectomy.

METHODS

To evaluate the influence of the type of approach, in causing or avoiding certain complaints in hysterectomies a prospective nationwide study was conducted comprising all hysterectomies for benign disease performed in Finland during 1996. The primary outcomes of interest were the operation-related morbidity, common surgical details and post-operative complications.

RESULTS

A total of 10 110 hysterectomies, including 5875 abdominal, 1801 vaginal and 2434 laparoscopic operations showed a low rate of overall complications, 17.2, 23.3 and 19.0% respectively. Infections were the most common complications with incidences of 10.5, 13.0 and 9.0% in the abdominal, vaginal and laparoscopic group respectively. The most severe type of haemorrhagic events occurred in 2.1, 3.1 and 2.7% in the abdominal, vaginal and laparoscopic group respectively. Ureter injuries were predominant in laparoscopic group [relative risk (RR) 7.2 compared with abdominal] whereas bowel injuries were most common in vaginal group (RR 2.5 compared with abdominal). Surgeons who had performed >30 laparoscopic hysterectomies had a significantly lower incidence of ureter and bladder injuries (0.5 and 0.8% respectively) than those who had performed < or =30 operations (2.2 and 2.0% respectively). A decreasing trend of bowel complications was also seen with increasing experience in vaginal hysterectomies.

CONCLUSIONS

This large-scale observational study on hysterectomies provides novel information on operation-related morbidity of abdominal, vaginal or laparoscopic approach. The results support the importance of the experience of the surgeon in reducing severe complications, especially in laparoscopic and vaginal hysterectomies.

Resistance of different surfactant preparations to inactivation by meconium

A disease similar to acute respiratory distress syndrome may occur in neonates after aspiration of meconium. The aim of the study was to compare the inhibitory effects of human meconium on the following surfactant preparations suspended at a concentration of 2.5 mg/mL: Curosurf, Alveofact, Survanta, Exosurf, Pumactant, rabbit natural surfactant from bronchoalveolar lavage, and two synthetic surfactants based on recombinant surfactant protein-C (Venticute) or a leucine/lysine polypeptide. Minimum surface tension, determined with a pulsating bubble surfactometer, was increased >10 mN/m at meconium concentrations >or=0.04 mg/mL for Curosurf, Alveofact, or Survanta, >or=0.32 mg/mL for recombinant surfactant protein-C, >or=1.25 mg/mL for leucine/lysine polypeptide, and >or=20 mg/mL for rabbit natural surfactant. The protein-free synthetic surfactants Exosurf and Pumactant did not reach minimum surface tension <10 mN/m even in the absence of meconium. We conclude that surfactant activity is inhibited by meconium in a dose-dependent manner. Recombinant surfactant protein-C and leucine/lysine polypeptide surfactant were more resistant to inhibition than the modified natural surfactants Curosurf, Alveofact, or Survanta but less resistant than natural lavage surfactant containing surfactant protein-A. We speculate that recombinant hydrophobic surfactant proteins or synthetic analogs of these proteins can be used for the design of new surfactant preparations that are relatively resistant to inactivation and therefore suitable for treatment of acute respiratory distress syndrome.

Free energy barrier estimation of unfolding the alpha-helical surfactant-associated polypeptide C

Molecular dynamics simulations were conducted to estimate the free energy barrier of unfolding surfactant-associated polypeptide C (SP-C) from an alpha-helical conformation. Experimental studies indicate that while the helical fold of SP-C is thermodynamically stable in phospholipid micelles, it is metastable in a mixed organic solvent of CHCl3/CH3OH/0.1 M HCl at 32:64:5 (v/v/v), in which it undergoes an irreversible transformation to an insoluble aggregate that contains beta-sheet. On the basis of experimental observations, the free energy barrier was estimated to be approximately 100 kJ/mole by applying Eyring's transition state theory to the experimental rate of unfolding [Protein Sci 1998;7:2533-2540]. These studies prompted us to carry out simulations to investigate the unwinding process of two helical turns encompassing residues 25-32 in water and in methanol. The results give an upper bound estimation for the free energy barrier of unfolding of SP-C of approximately 20 kJ/mole. The results suggest a need to reconsider the applicability of a single-mode activated process theory to protein unfolding.

C-Peptide Binding to Human Cell Membranes: Importance of Glu27

In addition to its established role in proinsulin folding, C-peptide has a function in regulation of cellular activity. The 31-residue peptide influences renal, vascular, and metabolic functions in patients with insulin-dependent diabetes mellitus. Binding to cells has been demonstrated for C-peptide, which can be displaced by its C-terminal pentapeptide. We have now used fluorescence correlation spectroscopy to investigate structural requirements on the pentapeptide part for C-peptide binding. All pentapeptide residues, E(27)GSLQ(31), were individually replaced with Ala and the capacity of the resulting peptides to displace rhodamine-labelled full-length human C-peptide from human renal tubular cell membranes was determined. This showed that Glu27 is essential for displacement, while replacement of Gly28 with Ala has little effect, and replacement of any of the three most C-terminal residues had intermediate effects. Morevover, free Glu displaces full-length C-peptide to about 50%, while free Ala, C-peptide(1-26), and the truncated pentapeptide, corresponding to the tetrapeptide G(28)SLG(31), have no displacing capacity. The peptides EVARQ (corresponding to the rat C-terminal pentapeptide) and ELGGGPGAG (corresponding to positions 11-19 of human C-peptide) do not displace human C-peptide. These results indicate that Glu27 of C-peptide is critically involved in binding to cellular targets.

Altered expression of receptors for thyroid hormone and insulin-like growth factor-I during reconstitution after allogeneic hematopoietic stem cell transplantation

Treatment with neuroendocrine hormones has been suggested to promote reconstitution of the immune system after hematopoietic stem cell transplantation (HSCT). We investigated the expression of genes encoding receptors for growth hormone (GH), insulin-like growth factor-I (IGF-I) and triiodothyronine (T3), at various time points after HSCT in 16 patients and 15 healthy controls. Peripheral blood mononuclear cells were isolated and RNA for GH receptor (GHR), IGF-I receptor (IGF-IR) and thyroid hormone receptor (TRalpha1) was amplified by RT-PCR. The expression of the genes was compared with the expression of beta-actin. We demonstrate increased expression of TRalpha1 RNA in patients at 1.5 months post HSCT, compared to a group of healthy controls, and decreased expression of IGF-IR RNA at 2 and 3 months post HSCT, compared to the controls. Serum from three of the patients was also analyzed for levels of T3, T4, TSH and IGF-I at several time points after HSCT. Serum levels for T3, thyroxine (T4), thyroid stimulating hormone (TSH) and IGF-I were within the normal range in all samples. Our results on the molecular level indicate a role for thyroid hormones and IGF-I in immune reconstitution after HSCT, even though the serum levels of T3, T4, TSH and IGF-I are normal.

Membrane activity of (Cys48Ser) lung surfactant protein B increases with dimerisation

One of the possible functions of lung surfactant protein B (SP-B), an hydrophobic membrane-associated saposin-like protein, is to reduce the alveolar surface tension by promoting insertion of phospholipids into the air/liquid interface of the lung. SP-B is a covalent homodimer; Cys48 of two polypeptides form an intermolecular disulphide bond. In order to test whether dimerisation of SP-B is important for surfactant function, transgenic mice which express (Cys48Ser) human SP-B in a mouse SP-B null background were generated. In previous studies (Cys48Ser)SP-B showed a concentration-dependent in vitro activity, suggesting that it may form non-covalent dimers. Here (Cys48Ser)SP-B isolated from bronchoalveolar lavage of transgenic mice was studied at different concentrations by circular dichroism (CD) spectroscopy, pulsating bubble surfactometry, mass spectrometry and reversed-phase HPLC. The results indicate that (Cys48Ser)SP-B, both in a phospholipid environment and in organic solvents, is largely monomeric and exhibits low activity at concentrations lower than 1 -2 microM, while at higher concentrations it forms non-covalent dimers, which are nearly functionally equivalent to native SP-B in vitro. Furthermore, electrospray mass spectrometry showed that more dimers were found relative to the monomer when the polarity of the solvent was decreased, and when the concentration of SP-B increased. (Cys48Ser)SP-B also eluted earlier than native SP-B in reversed-phase HPLC. Taken together, these results indicate that a polar surface is buried upon dimerisation, thereby promoting formation of interchain ion pairs between Glu51-Arg52' and Glu51'-Arg52.

Peptide repertoire of human cerebrospinal fluid: novel proteolytic fragments of neuroendocrine proteins

Polypeptides in human cerebrospinal fluid (CSF), isolated by phase separation in chloroform-methanol-water and reversed-phase HPLC, were characterised by sequence analysis and mass spectrometry. This identified the presence of peptide fragments of testican, neuroendocrine specific protein VGF, neuroendocrine protein 7B2, chromogranin B/secretogranin I, chromogranin A, osteopontin, IGF-II E-peptide and proenkephalin. The majority of these fragments were generated by proteolysis at dibasic sites, suggesting that they are derived by activities related to prohormone convertase(s). Several of the fragments have previously not been detected, and their functions in CSF or elsewhere are unknown. A characteristic feature of all these fragments is a very high content of acidic residues, in particular glutamic acid. In addition to the fragments of neuroendocrine proteins, endothelin-binding receptor-like protein 2, ribonuclease 1, IGF-binding protein 6, albumin, alpha1-acid glycoprotein 1, prostaglandin-H2 D-isomerase, apolipoprotein A1, transthyretin, beta2-microglobulin, ubiquitin, fibrinopeptide A, and C4A anaphylatoxin were found.

Prediction of amyloid fibril-forming proteins

In Alzheimer's disease and spongiform encephalopathies proteins transform from their native states into fibrils. We find that several amyloid-forming proteins harbor an alpha-helix in a polypeptide segment that should form a beta-strand according to secondary structure predictions. In 1324 nonredundant protein structures, 37 beta-strands with > or =7 residues were predicted in segments where the experimentally determined structures show helices. These discordances include the prion protein (helix 2, positions 179-191), the Alzheimer amyloid beta-peptide (Abeta, positions 16-23), and lung surfactant protein C (SP-C, positions 12-27). In addition, human coagulation factor XIII (positions 258-266), triacylglycerol lipase from Candida antarctica (positions 256-266), and d-alanyl-d-alanine transpeptidase from Streptomyces R61 (positions 92-106) contain a discordant helix. These proteins have not been reported to form fibrils but in this study were found to form fibrils in buffered saline at pH 7.4. By replacing valines in the discordant helical part of SP-C with leucines, an alpha-helix is found experimentally and by secondary structure predictions. This analogue does not form fibrils under conditions where SP-C forms abundant fibrils. Likewise, when Abeta residues 14-23 are removed or changed to a nondiscordant sequence, fibrils are no longer formed. We propose that alpha-helix/beta-strand-discordant stretches are associated with amyloid fibril formation.

Cardiovascular status of carriers of the apolipoprotein A-I(Milano) mutant: the Limone sul Garda study

BACKGROUND

Carriers of the apolipoprotein A-I(Milano) (apoA-I(M)) mutant present with very low plasma HDL cholesterol and moderate hypertriglyceridemia, apparently not leading to premature coronary heart disease. The objective of this study was to establish whether this high-risk lipid/lipoprotein profile is associated with structural changes in the carotid arteries and heart, indicative of preclinical atherosclerosis.

METHODS AND RESULTS

Twenty-one A-I(M) carriers were compared with age- and sex-matched control subjects from the same kindred and with 2 series of matched subjects with primary hypoalphalipoproteinemia (HA). Structural changes in the carotid arteries were defined as the intima-media thickness (IMT) measured by B-mode ultrasound. HA subjects, both recruited among patients attending our Lipid Clinic and blood donors, showed significant thickening of the carotids (average IMT, 0.86+/-0.25 and 0.88+/-0.29 mm, respectively) compared with control subjects (average IMT, 0.64+/-0.12 mm); the apoA-I(M) carriers instead showed normal arterial thickness (average IMT, 0.63+/-0.10 mm). Moreover, a significantly higher prevalence of atherosclerotic plaques was found in patients and blood donors with HA (both 57%) compared with apoA-I(M) carriers (33%) and control subjects (21%). Echocardiographic findings and maximal treadmill ECG did not differ significantly between apoA-I(M) carriers and control subjects, apart from a slight increase in left ventricular end-diastolic dimension in the carriers.

CONCLUSIONS

Despite severe HA, carriers of the apoA-I(M) mutant do not show structural changes in the arteries and heart, in contrast to HA subjects, who are characterized by a marked increase in carotid IMT and increased prevalence of atherosclerotic plaques.

Heteromeric interactions among nucleoid-associated bacterial proteins: localization of StpA-stabilizing regions in H-NS of Escherichia coli

The nucleoid-associated proteins H-NS and StpA in Escherichia coli bind DNA as oligomers and are implicated in gene regulatory systems. There is evidence for both homomeric and heteromeric H-NS-StpA complexes. The two proteins show differential turnover, and StpA was previously found to be subject to protease-mediated degradation by the Lon protease. We investigated which regions of the H-NS protein are able to prevent degradation of StpA. A set of truncated H-NS derivatives was tested for their ability to mediate StpA stability and to form heteromers in vitro. The data indicate that H-NS interacts with StpA at two regions and that the presence of at least one of the H-NS regions is necessary for StpA stability. Our results also suggest that a proteolytically stable form of StpA, StpA(F21C), forms dimers, whereas wild-type StpA in the absence of H-NS predominantly forms tetramers or oligomers, which are more susceptible to proteolysis.

Molecular genetic characterisation of frontotemporal dementia on chromosome 3

We have previously localized a locus causing familial nonspecific dementia to the centromeric region of chromosome 3 in a pedigree from the Jutland area of Denmark. This pedigree shows anticipation. Here we present further analysis of these anticipation data which are suggestive of trinucleotide repeat expansion involvement. We also outline our strategies to clone the mutant gene via its putative associated trinucleotide repeat sequence.