A comparison of rCBF patterns during letter and semantic fluency

To evaluate the functional neuroanatomies underlying letter and category fluency, 18 normal controls were studied with oxygen-15 water regional cerebral blood flow positron emission tomography. Three counterbalanced conditions each consisted of 6 trials (45 s each): letter fluency (generating words when cued with a particular letter), semantic fluency (generating words when cued with a particular category), and a control condition (generating days of the week and months of the year). Relative to the control, participants activated similar brain regions during both fluency tasks, including the anterior cingulate, left prefrontal regions, thalamus, and cerebellum; reductions were found in parietal and temporal regions. In a direct comparison of the 2 fluency tasks, inferior frontal cortex and temporoparietal cortex (hypothesized to participate in a phonologic loop for accessing word pronunciation) were activated more during letter than semantic fluency, whereas left temporal cortex (associated with access to semantic storage) was activated more during semantic than letter fluency. This study identifies subtle differences in the neural networks underlying letter and semantic fluency that may underlie the dissociation of these abilities in patients.

A new rat model of small vessel stenting

OBJECTIVES

Restenosis is the major complication of coronary angioplasty and stenting. In addition, the small vessel diameter represents a major limitation to the wide use of the technology. The aim of this study was to assess the feasibility and the vascular response of stent deployment in rat small vessels.

METHODS

In 40 Wistar rats (500-550 g) a Nir stent crimped on a 1.5 mm Comet angioplasty balloon catheter was deployed at high pressure in the common carotid artery. Neointimal area, neointima/media ratio and the arterial dimension were assessed immediately and at 7, 14, 21, and 28 days after stenting.

RESULTS

After stent deployment, the neointimal area and the neointima/media ratio increased progressively and peaked at 14 days (p < 0.05 vs 0 and 7 days). Alpha-actin-positive cells were found circumferentially organized on the lumen surface. At 21 and 28 days after stenting, the neointima and the neointima/media ratio were not statistically different compared with the results obtained fourteen days after stent deployment. No significant differences in the area of external elastic lamina were observed during the study period. In contrast, the internal lumen area was reduced significantly at 14, 21, and 28 days after the stent deployment. Subacute thrombosis rate after stent implantation was 26.5 %.

CONCLUSIONS

The results of this study demonstrated that the balloon expandable stents can be safely placed into rat arteries and the reduction of the internal arterial lumen observed after stent deployment was only due to the neointima formation whereas remodeling did not occur.

Removal of the N-terminal hexapeptide from human beta2-microglobulin facilitates protein aggregation and fibril formation

The solution structure and stability of N-terminally truncated beta2-microglobulin (deltaN6beta2-m), the major modification in ex vivo fibrils, have been investigated by a variety of biophysical techniques. The results show that deltaN6beta2-m has a free energy of stabilization that is reduced by 2.5 kcal/mol compared to the intact protein. Hydrogen exchange of a mixture of the truncated and full-length proteins at microM concentrations at pH 6.5 monitored by electrospray mass spectrometry reveals that deltaN6beta2-m is significantly less protected than its wild-type counterpart. Analysis of deltaN6beta2-m by NMR shows that this loss of protection occurs in beta strands I, III, and part of II. At mM concentration gel filtration analysis shows that deltaN6beta2-m forms a series of oligomers, including trimers and tetramers, and NMR analysis indicates that strand V is involved in intermolecular interactions that stabilize this association. The truncated species of beta2-microglobulin was found to have a higher tendency to self-associate than the intact molecule, and unlike wild-type protein, is able to form amyloid fibrils at physiological pH. Limited proteolysis experiments and analysis by mass spectrometry support the conformational modifications identified by NMR and suggest that deltaN6beta2-m could be a key intermediate of a proteolytic pathway of beta2-microglobulin. Overall, the data suggest that removal of the six residues from the N-terminus of beta2-microglobulin has a major effect on the stability of the overall fold. Part of the tertiary structure is preserved substantially by the disulfide bridge between Cys25 and Cys80, but the pairing between beta-strands far removed from this constrain is greatly perturbed.

Enhanced cardiac function in transgenic mice expressing a Ca(2+)-stimulated adenylyl cyclase

The predominant functional adenylyl cyclases normally expressed in cardiac tissue and coupled to beta-adrenergic receptors are inhibited by micromolar Ca(2+) concentration. To modify the overall balance of activities, we have generated transgenic mice expressing the Ca(2+)-stimulatable adenylyl cyclase type 8 (AC8) specifically in the heart. AC activity is increased by at least 7-fold in heart membranes from transgenic animals and is stimulated by Ca(2+) in the same range of concentration that inhibits the endogenous activity. Moreover, the in vivo basal protein kinase A activity was augmented 4-fold. Overexpression of AC8 in the heart has no detrimental consequences on global cardiac function. Basal heart rate and contractile function, measured by noninvasive echocardiography, were unchanged. In contrast, on release of parasympathetic tone, the intrinsic contractility is heightened and unresponsive to further beta-adrenergic receptor stimulation. AC8 transgenic mice thus represent an original model to investigate the relative influence of Ca(2+) and cAMP on cardiac function within a phenotype of enhanced cardiac contractility and relaxation.

Mouse Hsp25, a small shock protein. The role of its C-terminal extension in oligomerization and chaperone action

Under conditions of cellular stress, small heat shock proteins (sHsps), e.g. Hsp25, stabilize unfolding proteins and prevent their precipitation from solution. 1H NMR spectroscopy has shown that mammalian sHsps possess short, polar and highly flexible C-terminal extensions. A mutant of mouse Hsp25 without this extension has been constructed. CD spectroscopy reveals some differences in secondary and tertiary structure between this mutant and the wild-type protein but analytical ultracentrifugation and electron microscopy show that the proteins have very similar oligomeric masses and quaternary structures. The mutant shows chaperone ability comparable to that of wild-type Hsp25 in a thermal aggregation assay using citrate synthase, but does not stabilize alpha-lactalbumin against precipitation following reduction with dithiothreitol. The accessible hydrophobic surface of the mutant protein is less than that of the wild-type protein and the mutant is also less stable at elevated temperature. 1H NMR spectroscopy reveals that deletion of the C-terminal extension of Hsp25 leads to induction of extra C-terminal flexibility in the molecule. Monitoring complex formation between Hsp25 and dithiothreitol-reduced alpha-lactalbumin by 1H NMR spectroscopy indicates that the C-terminal extension of Hsp25 retains its flexibility during this interaction. Overall, these data suggest that a highly flexible C-terminal extension in mammalian sHsps is required for full chaperone activity.

Gbetagamma-dependent phosphoinositide 3-kinase activation in hearts with in vivo pressure overload hypertrophy

Activation of phosphoinositide 3-kinases is coupled to both phosphotyrosine/growth factor and G protein-coupled receptors. We explored the role of phosphoinositide 3-kinase activation in myocardium during in vivo pressure overload hypertrophy in mice. Cytosolic extracts from wild type hypertrophied hearts showed a selective increase in the phosphoinositide 3-kinase gamma isoform. To address the role of G protein-coupled receptor-mediated activation of phosphoinositide 3-kinase, we used transgenic mice with cardiac-specific overexpression of a Gbetagamma sequestering peptide. Extracts from hypertrophied transgenic hearts showed complete loss of phosphoinositide 3-kinase activation, indicating a Gbetagamma-dependent process. To determine the class of G proteins that contribute Gbetagamma dimers for in vivo phosphoinositide 3-kinase activation, two strategies were used: 1) transgenic mice with cardiac-specific overexpression of a G(q) inhibitor peptide and 2) pertussis toxin treatment prior to pressure overload in wild type mice. Pressure overloaded G(q) inhibitor transgenic mice showed a complete absence of phosphoinositide 3-kinase activation, whereas pretreatment with pertussis toxin showed robust phosphoinositide 3-kinase activation. Taken together, these data demonstrate that activation of the phosphoinositide 3-kinase during in vivo pressure overload hypertrophy is Gbetagamma-dependent and the Gbetagamma dimers arise from stimulation of G(q)-coupled receptors.

Mice reconstituted with DNA polymerase beta-deficient fetal liver cells are able to mount a T cell-dependent immune response and mutate their Ig genes normally

The ubiquitously expressed, error-prone DNA polymerase beta (polbeta) plays a role in base excision repair, and the involvement of this molecule in the nonhomologous end joining (NHEJ) process of DNA repair has recently been demonstrated in yeast. Polbeta-deficient mice are not viable, and studies on conditional mutants revealed a competitive disadvantage of polbeta(-/-) vs. wild-type cells. We show here that polbeta-deficient mice survive up to day 18.5 postcoitum, but die perinatally; a circumstance that allowed the investigation of a potential role of polbeta in lymphocyte development by transfer of fetal liver cells (FLC) derived from polbeta(-/-) embryos into lethally irradiated hosts. FLC transfers using mutant cells lead to an almost normal reconstitution of the lymphocyte compartment, indicating that polbeta-deficiency does not prevent V(D)J recombination, which is known to employ factors of the NHEJ pathway. Mice reconstituted with polbeta(-/-) FLC mount a normal T cell-dependent immune response against the hapten (4-hydroxy-3-nitrophenyl) acetyl (NP). Moreover, germinal center B cells from NP-immunized reconstituted mice show normal levels and patterns of somatic point mutations in their rearranged antibody genes, demonstrating that polbeta is not critically involved in somatic hypermutation.

Coronary and major vascular disease: aggressive screening and priority-based therapy

It is well know that atherosclerosis can simultaneously affect different vascular subsystems, and patients with diffuse atherosclerosis can be a major management problem both for preoperative evaluation and for intraoperative management. The authors have conducted a prospective study to evaluate the prevalence of coronary artery disease in arteriopathic patients, and vice versa, to assess the effectiveness of aggressive screening together with a priority-based approach. Study 1 consisted of 1,000 consecutive non-emergent patients who were affected by abdominal aortic or carotid disease and were screened for the presence of coronary artery disease before surgery with a newly developed clinical risk assessment. They were stratified into three risk categories with different preoperative evaluation strategies. When coronary artery disease was concomitantly demonstrated in these patients, the choice of surgical method was based on priorities, and the use of combined surgical procedures as required. In study 2, 1,000 consecutive patients that required coronary angiography for suspected coronary artery disease were screened for the presence of carotid or abdominal aortic pathology, directly in the cardiac catheter laboratory during coronary angiography, by obtaining views of the aortic arch and abdominal aorta. Surgical approaches paralleled those of study 1. The results for study 1 showed that 720 patients (72%) were affected by abdominal aortic disease, 238 (24%) by carotid disease and 42 (4%) by both pathologies. Significant coronary artery disease was found in 152 patients (15%), of these 123 (81.5%) were affected by abdominal aortic disease and 29 (18.5%) by carotid artery disease. Abdominal aortic surgery was performed directly or after myocardial revascularization, with an overall mortality rate of 4/718 (0.6%), and a perioperative myocardial infarction rate of 10/718 (1.4%). For patients with carotid artery disease, the completed screening and possible therapy for coronary artery disease resulted in an in-hospital mortality rate of 2/238 (0.8%), and a perioperative myocardial infarction rate of 2/238 (0.8%). There were no significant differences in these rates between patients with or without coronary artery disease. Results for study 2 showed that of the 1000 consecutive patients enrolled for suspicion of coronary artery disease, 767 (77%) were affected by significant coronary artery disease. Among these, 38 (4.9%) had a surgically correctable aortic disease and 31 (4%) a surgically correctable carotid disease, which was monolateral and bilateral in 22 (74%) and nine (26%) patients, respectively, and four (0.5%) were diagnosed with both pathologies. These arteriopathic patients were treated for their coronary and vascular disease with no in-hospital mortality nor perioperative myocardial infarction. In patients with multiple vascular involvement, both coronary and vascular surgery can be performed with low risk when aggressive screening and priority-based therapy are adopted.

Effects of hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin on smooth muscle cell proliferation in vitro and neointimal formation in vivo after vascular injury

OBJECTIVES

We sought to evaluate the effects of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on vascular smooth muscle cell (VSMC) proliferation in vitro and neointimal formation in vivo after vascular injury.

BACKGROUND

Neointimal hyperplasia after vascular injury is responsible for restenosis after arterial stenting, whereas arterial remodeling and neointimal formation are the causes of restenosis after percutaneous transluminal coronary angioplasty.

METHODS

We assessed the effect of simvastatin on in vitro VSMC proliferation. To study the effects of simvastatin in vivo, balloon injury and stent deployment were performed in the common carotid artery of rats. Neointimal area was measured two weeks later in the balloon injury model and three weeks after stent deployment.

RESULTS

Simvastatin markedly inhibits VSMC proliferation in vitro. In vivo, simvastatin reduced, in a dose-dependent manner, the neointimal area and the neointima-media ratio after balloon injury from 0.266 +/- 0.015 mm2 to 0.080 +/- 0.026 mm2 and from 1.271 +/- 0.074 to 0.436 +/- 0.158 (p < 0.001 vs. control rats) at the highest dose. Simvastatin also significantly reduced the neointimal formation and the neointima-media ratio after stenting from 0.508 +/- 0.035 mm2 to 0.362 +/- 0.047 mm2 (p < 0.05 vs. control rats) and from 2.000 +/- 0.136 to 1.374 +/- 0.180 (p < 0.05 vs. control rats). The vessel thrombosis rate after stent deployment was 30% in the control group and 11.1% in the treated group (p = NS). Moreover, the systemic administration of simvastatin did not affect hepatic and renal functions, blood pressure or heart rate.

CONCLUSIONS

Simvastatin potently inhibits VSMC proliferation in vitro and reduces neointimal formation in a rat model of vascular injury.

Specific relationship between prefrontal neuronal N-acetylaspartate and activation of the working memory cortical network in schizophrenia

OBJECTIVE

Abnormal activation of the dorsolateral prefrontal cortex and a related cortical network during working memory tasks has been demonstrated in patients with schizophrenia, but the responsible mechanism has not been identified. The present study was performed to determine whether neuronal pathology of the dorsolateral prefrontal cortex is linked to the activation of the working memory cortical network in patients with schizophrenia.

METHOD

The brains of 13 patients with schizophrenia and 13 comparison subjects were studied with proton magnetic resonance spectroscopic ((1)H-MRS) imaging (to measure N-acetylaspartate as a marker of neuronal pathology) and with [(15)O]water positron emission tomography (PET) during performance of the Wisconsin Card Sorting Test (to measure activation of the working memory cortical network). An independent cohort of patients (N=7) was also studied in a post hoc experiment with (1)H-MRS imaging and with the same PET technique during performance of another working memory task (the "N-back" task).

RESULTS

Measures of N-acetylaspartate in the dorsolateral prefrontal cortex strongly correlated with activation of the distributed working memory network, including the dorsolateral prefrontal, temporal, and inferior parietal cortices, during both working memory tasks in the two independent groups of patients with schizophrenia. In contrast, N-acetylaspartate in other cortical regions and in comparison subjects did not show these relationships.

CONCLUSIONS

These findings directly implicate a population of dorsolateral prefrontal cortex neurons as selectively accounting for the activity of the distributed working memory cortical network in schizophrenia and complement other evidence that dorsolateral prefrontal cortex connectivity is fundamental to the pathophysiology of the disorder.

Chlamydia pneumoniae DNA detection in peripheral blood mononuclear cells is predictive of vascular infection

Abdominal aortic aneurysm tissue and peripheral blood mononuclear cells (PBMC) of 41 consecutive subjects undergoing abdominal aortic aneurysm surgery were analyzed by polymerase chain reaction (PCR) for the presence of Chlamydia pneumoniae, Mycoplasma pneumoniae, and Helicobacter pylori DNA. Twenty patients (49%) were positive for C. pneumoniae DNA-16 (39%) in both PBMC and aneurysm tissue, 3 (7.3%) in PBMC only, and 1 (2.4%) in the artery specimen only. Previous exposure to C. pneumoniae was confirmed in 19 (95%) of the 20 PCR positive subjects by C. pneumoniae-specific serology, using the microimmunofluorescence test. None was positive for H. pylori or M. pneumoniae DNA, either in the PBMC or in the artery specimens. In conclusion, carriage of C. pneumoniae DNA is common both in PBMC and in abdominal aortic tissue from patients undergoing abdominal aneurysm surgery. Blood PCR may be a useful tool for identifying subjects carrying C. pneumoniae in the vascular wall.

Combination of granulocyte-macrophage colony-stimulating factor (GM-CSF) anf erythropoietin (EPO) for the treatment of advanced non-responsive chronic lymphocytic leukemia

We report the use of a colony-stimulating granulocyte-macrophage factor (GM/CSF) and erythropoietin (EPO) combination as salvage treatment in four heavily-pretreated patients with refractory/ recurrent B-CLL. Induction therapy was subcutaneous GM-CSF 2.5 microg/ kg, and EPO, 150 units/kg both daily for the first 14 d. Maintenance therapy was GM-CSF on days 1, 3 and 5 and Epo on days 2, 4 and 6 at the same doses with weekly recycling. All the patients responded favourably. A significant reduction of lymphocytosis, lymphoadenomegaly, and organomegaly was obtained within one month of therapy. The number of infections and transfusional requirement decreased dramatically. The hemoglobin increased to over 11 g/dl in 3 out of 4 patients. With a median follow-up of 11 months (range 5-13) we observed 4 partial responses (NCI/IWCLL) and only one progression after a 10-month partial response. This combination regimen seems very active, safe and easy to administer. It may represent a promising therapeutical option in heavily pretreated patients. Further clinical and biological studies on a larger cohort of patients are needed to confirm these preliminary data, to clarify the hypothetical interactions between these cytokines and B-CLL cell proliferation pathways, and to establish if this therapy may have an impact on survival.

Restriction of HIV type 1 infection in macrophages heterozygous for a deletion in the CC-chemokine receptor 5 gene

Homozygosity for a 32-base pair deletion (delta32) within the CC-chemokine receptor 5 (CCR5) gene confers resistance to infection by R5-type HIV-1 isolates. To ascertain how CCR5delta32 heterozygosity influences the susceptibility of lymphocytes and macrophages to HIV-1 infection, peripheral blood lymphocytes (PBLs) and monocyte-derived macrophages (MDMs) from three HIV-1-uninfected CCR5delta32 heterozygous infants and three HIV-1-uninfected CCR5 wild-type homozygous infants were exposed to two R5-type primary isolates. HIV-1 infection was monitored by DNA-PCR and p24 antigen determination; CCR5 and CCR5delta32 transcripts were quantified by competitive reverse transcription-PCR. Wild-type homozygous MDMs and PBLs and heterozygous PBLs were infected by both viral isolates, albeit with different efficiencies, but heterozygous MDMs showed restriction to HIV-1 infection. Lower levels of CCR5 mRNA and protein expression were found in heterozygous versus wild-type homozygous MDMs and PBLs. Interestingly, wild-type homozygous MDMs showed higher levels of CCR5 mRNA expression compared with wild-type homozygous PBLs, while heterozygous MDMs had lower levels of CCR5 wild-type mRNA and a higher CCR5delta32/CCR5 mRNA ratio compared with heterozygous PBLs. These findings suggest that CCR5delta32 heterozygosity confers a different degree of protection against HIV-1 in PBLs and MDMs, depending on the ratio of wild-type and mutant CCR5 mRNA in the two cell types, and may delay virus spread in the host by preventing infection of monocytes and macrophages.

Tendamistat surface accessibility to the TEMPOL paramagnetic probe

TEMPOL, the soluble spin-label 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl, has been used to determine the surface characteristics of tendamistat, a small protein with a well-characterised structure both in solution and in the crystal. A good correlation has been found between predicted regions of exposed protein surface and the intensity attenuations induced by the probe on 2D NMR TOCSY cross peaks of tendamistat in the paramagnetic water solution. All the high paramagnetic effects have been interpreted in terms of more efficient competition of TEMPOL with water molecules at some surface positions. The active site of tendamistat coincides with the largest surface patch accessible to the probe. A strong hydration of protein N and C termini can also be suggested by this structural approach, as these locations exhibit reduced paramagnetic perturbations. Provided that the solution structure is known, the use of this paramagnetic probe seems to be well suited to delineate the dynamic behaviour of the protein surface and, more generally, to gain relevant information about the molecular presentation processes.

Chlamydia pneumoniae eradication from carotid plaques. Results of an open, randomised treatment study

OBJECTIVE

to determine the effect of specific antibiotic treatment with roxithromycin in the eradication of Chlamydia pneumoniae from carotid artery plaques.

DESIGN

prospective open randomised treatment study.

PATIENTS AND METHODS

we analysed 32 patients (16 females, mean age 70.1+/-14.7 years) who underwent surgery for the removal of atherosclerotic plaques from carotid arteries. During surgery samples of lingual vein and superior thyroid artery were also taken. Before surgery, patients were randomised to receive either roxithromycin 150 mg twice daily or no treatment. Sixteen patients were treated with antibiotic for a mean of 26 days (range 17-35 days). The two groups of patients were comparable in terms of age, sex, risk factors, and seroprevalence for C. pneumoniae. We applied a semi-nested polymerase chain reaction (PCR) technique to the carotid plaques, lingual vein, and thyroid artery samples. Blood samples were obtained from the patients for the determination of C. pneumoniae IgG, IgA, and IgM antibody titres by a microimmunofluorescence technique.

RESULTS

in twelve out of sixteen non-treated patients we found evidence of C. pneumoniae DNA in the carotid plaques. Conversely, C. pneumoniae DNA was detected in only five out of sixteen treated patients (p=0.034, Chi-squared test). In all cases PCR was negative for the lingual vein and thyroid artery samples.

CONCLUSIONS

Roxithromycin seems effective in reducing the bacterial burden of C. pneumoniae within atherosclerotic plaques, although extended follow-up is needed to determine whether antibiotic treatment benefits long-term patient outcome.

Urinary neopterin and kynurenine in patients submitted to surgical stress with different inhalational anesthetics (halothane or isoflurane)

Measurements were taken of urinary levels of neopterin (NPT) and kynurenine (KYN), using an HPLC method for their simultaneous analysis in patients submitted to anesthetical surgical stress with two different inhalational anesthetics (halothane and isoflurane). We studied twenty-one women affected by uterine fibromyomatosis and submitted to total hysterectomy (mean age of 42.7+/-5.4 years). They showed the same pre-operative evaluation (ASA-1), and underwent the same i.v. anesthetic treatment. Our patients were randomized in two groups: Group A: 11 patients had halothane as an inhalational anesthetic drug for the maintenance of the anesthetic induction (mean time= 1 h). Group B: 10 patients had isoflurane. A significant decrease in urinary NPT and KYN, parallel to serum-NPT, was found 4 h after anesthetic induction. Raised NPT levels appeared 24 h after A.I. with significant increased levels after 7 days. A strong correlation between urinary and serum NPT levels was seen (Rs= 0.74; p < 0.001). Significantly low KYN levels were observed both 4 h and 24 h after A.I.. In addition to the delayed increase of the excretory KYN levels, significantly raised KYN levels in Group B (isoflurane) 48 h after A.I. (10.59+/-14.31 vs 5.99+/-7.17 micromol/mol creat.; p < 0.01) were shown, whereas in Group A (halothane) we observed a progressive increase as compared to the pre-surgery values starting from 72 h after surgery. Our data seem to show that: (a) it is possible to have a biochemical and non invasive monitoring of the anesthetical-surgical stress on MM "priming" activity; (b) the activation of the phagocyte compartment is one of the earlier immunological events after surgery (NPT), but the efficiency of this "priming" appears to be delayed (KYN); (c) isoflurane appears to induce an earlier recovery in MM activation.

Bone age progression during five years of substitutive therapy for the induction of puberty in thalassemic girls--effects on height and sitting height

It is known that in thalassemic patients there is a disproportion between lower and upper segments whose causes have not yet been identified. We evaluated whether the administration of estrogens to induce puberty in hypogonadic thalassemic girls caused an inappropriate acceleration of bone maturation and whether this had a negative influence on final and sitting height.

MATERIALS AND METHODS

Twelve thalassemic patients with spontaneous puberty (Group A) and seven patients with hypogonadism (Group B) were studied. The mutations of the beta gene were identified by DNA analysis. We took into account four observations, ranging from the onset of spontaneous puberty in group A or the start of substitutive therapy in group B, to 5 years later. At each observation we considered: chronological age (CA), bone age (BA), height (Ht) expressed in cm and as standard deviation score (HtSDS) calculated with respect to CA (HtSDSCA) and BA (HtSDSBA), growth spurt, sitting height, expressed as SDS (SH-SDS), and height gain (HG). The delta BA and delta CA were calculated between the first and the final observation values to evaluate the bone age acceleration (delta BA/delta CA).

RESULTS

No acceleration of BA was noted. delta BA/delta CA was 0.98 +/- 0.1 in group A and 0.89 +/- 0.1 in group B (p > 0.05). All patients in group B had the most severe form (beta degree/beta degree) of thalassemia. During the final observation, SH-SDS was -1.43 +/- 1.2 and -2.9 +/- 0.6 in group A and B respectively (p < 0.002), while no difference between the two groups for HtSDSCA and HtSDSBA was observed. HG was greater in group A than in group B (17.7 +/- 5.4 cm vs 10.8 +/- 5.2 cm) (p < 0.002), such as the spurt 8.6 +/- 1.4 cm (group A) and 6.1 +/- 2.6 cm (group B) (p < 0.05).

CONCLUSIONS

Girls with hypogonadism did not show an inappropriate acceleration of BA, as they reached near final height similar to girls with spontaneous puberty. The auxological parameters showed a more severe body disproportion with the prevalence of the lower segment in the hypogonadic girls. This could be explained by a higher degree of bone marrow hyperplasia related to the most severe form of thalassemia and a higher blood consumption. As a consequence, damage at the vertebral level might determine an inability of the bone tissue to respond to estrogens. We suggest beginning estrogen therapy earlier in order to obtain better truncal growth.

Structural defects of a Pax8 mutant that give rise to congenital hypothyroidism

Pax proteins are transcriptional regulators that play important roles during embryogenesis. These proteins recognize specific DNA sequences via a conserved element: the paired domain (Prd domain). The low level of organized secondary structure, in the free state, is a general feature of Prd domains; however, these proteins undergo a dramatic gain in alpha-helical content upon interaction with DNA ('induced fit'). Pax8 is expressed in the developing thyroid, kidney and several areas of the central nervous system. In humans, mutations of the Pax8 gene, which are mapped to the coding region of the Prd domain, give rise to congenital hypothyroidism. Here, we have investigated the molecular defects caused by a mutation in which leucine at position 62 is substituted for an arginine. Leu62 is conserved among Prd domains, and contributes towards the packing together of helices 1 and 3. The binding affinity of the Leu62Arg mutant for a specific DNA sequence (the C sequence of thyroglobulin promoter) is decreased 60-fold with respect to the wild-type Pax8 Prd domain. However, the affinities with which the wild-type and the mutant proteins bind to a non-specific DNA sequence are very similar. CD spectra demonstrate that, in the absence of DNA, both wild-type Pax8 and the Leu62Arg mutant possess a low alpha-helical content; however, in the Leu62Arg mutant, the gain in alpha-helical content upon interaction with DNA is greatly reduced with respect to the wild-type protein. Thus the molecular defect of the Leu62Arg mutant causes a reduced capability for induced fit upon DNA interaction.

Demonstration of viable Chlamydia pneumoniae in atherosclerotic plaques of carotid arteries by reverse transcriptase polymerase chain reaction

The presence of Chlamydia pneumoniae in atheromas has been demonstrated in several studies. Culture of the organism from arterial tissue has been difficult. We report the use of a reverse transcriptase polymerase chain reaction to detect viable Chlamydia pneumoniae in carotid atheromas. We analyzed 30 patients (14 females, mean age 69.6 +/- 8.8 years) who underwent surgery for the removal of atherosclerotic plaques from carotid arteries. During surgery, samples of lingual vein and superior thyroideal artery were also taken. We applied two molecular biology techniques to the carotid plaques on lingual vein or thyroideal artery samples: 1) polymerase chain reaction (PCR) and 2) reverse transcriptase-PCR (RT-PCR) for the detection of bacterial mRNA, employing PCR primers designed to detect a fragment of the 16S rRNA gene. Blood samples were obtained from the patients for determination of Chlamydia pneumoniae IgG, IgA, and IgM antibody titers by a microimmunofluorescence technique. The results of the present study confirmed the presence of viable Chlamydia pneumoniae in atheromas and support the hypothesis that the organism may be an active factor in the pathogenesis of atherosclerosis.

Diagnosis of mediastinal masses and principles of surgical tactics and technique for their treatment

The diagnosis of a mediastinal mass is first based on clinical features, supplemented by epidemiological data and laboratory results providing information on the nature and localization of the mass. The diagnosis is then defined further on the basis of imaging studies. The first examinations required are standard radiographs, ultrasound scan or computed tomography scan and occasionally magnetic resonance imaging (MRI), angiography, and scintigraphy. These studies are followed by a thoracoscopy, mediastinoscopy, and the necessary biopsy techniques. Finally, the author describes the general principles of surgical tactics and techniques that generally lead to a total regression of the disease.

Context-dependent, neural system-specific neurophysiological concomitants of ageing: mapping PET correlates during cognitive activation

We used PET to explore the neurophysiological changes that accompany cognitive disability in ageing, with a focus on the frontal lobe. Absolute regional cerebral blood flow (rCBF) was measured in 41 healthy volunteers, evenly distributed across an age range of 18-80 years, during two task paradigms: (i) the Wisconsin Card Sorting Test (WCST), which depends heavily on working memory and is particularly sensitive to dysfunction of the dorsolateral prefrontal cortex (DLPFC); and (ii) Raven's Progressive Matrices (RPM), which may also have a working memory component, but depends more on visuo-spatial processing and is most sensitive to dysfunction of postrolandic regions. We used voxel-wise correlational mapping to determine age-related changes in WCST and RPM activation and developed a method to quantitate and localize statistical differences between the correlation maps for the two task paradigms. Because both WCST and RPM performance declined with age, as expected, correlational analyses were performed with and without partialling out the effect of task performance. Task-specific reductions of rCBF activation with age were found in the DLPFC during the WCST and in portions of the inferolateral temporal cortex involved in visuo-spatial processing during the RPM. We also found reduced ability to suppress rCBF in the right hippocampal region during the WCST and in mesial and polar portions of the prefrontal cortex during both task conditions. Task-dependent alterations with age in the relationship between the DLPFC and the hippocampus were also documented; because the collective pattern of changes in the hippocampal-DLPFC relationship with ageing was opposite to that seen in a previous study using dextroamphetamine, we postulated a dopaminergic mechanism. These results indicate that, despite some cognitive overlap between the two tasks and the age-related cognitive decline in both, many of the changes in rCBF activation with age were task-specific, reflecting functional alteration of the different neural circuits normally engaged by young subjects during the WCST and RPM. Reduced activation of areas critical for task performance (i.e. the DLPFC during the WCST and posterior visual association areas of the inferolateral temporal cortex during the RPM), in conjunction with the inability to suppress areas normally not involved in task performance (i.e. the left hippocampal region during the WCST and mesial polar prefrontal cortex during both the WCST and RPM), suggest that, overall, reduced ability to focus neural activity may be impaired in older subjects. The context dependency of the age-related changes is most consistent with systems failure and disordered connectivity.

Mucosal expression of carcinoembryonic antigen and carbohydrate antigen 19-9 in patients with gastritis and gastric cancer

Sixty-eight patients (45 males, 23 females) were studied in order to assess the usefulness of mucosal tissue concentrations of both carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) in detecting patients at high risk for gastric cancer. CEA and CA19-9 were assayed on cytosol obtained from multiple endoscopic biopsies of 41 patients with chronic superficial gastritis, 18 with chronic atrophic gastritis, and 9 with gastric cancer. Mucosal tissue concentrations of both CEA and CA19-9 increased from chronic superficial gastritis to chronic atrophic gastritis and to gastric cancer (p = 0.005 and p = 0.002, respectively). Mucosal CEA levels in patients with intestinal metaplasia (IM) were significantly higher than in nonmetaplastic mucosa (p = 0.04). Epithelial dysplasia was associated with higher, though not significant, tissue concentrations of both CEA and CA19-9 when compared with IM. Finally, a correlation between serum levels and tissue concentrations was observed only for CA19-9 (Pearson's correlation coefficient = 0.7). In conclusion, these data indicate that gastric mucosa of patients with chronic atrophic gastritis and intestinal metaplasia express high levels of both CA19-9 and CEA.

[Vascular complications during laparoscopy. An analysis of a personal case]

Vascular complications of laparoscopy most often occur during Veress needle or primary trocar placement. Veress needle punctures are insignificant and require no further treatment, whereas trocar induced vascular injuries can be catastrophic. The frequency of vascular or viscus injuries is difficult to calculate since several complications are not published. A vascular complication occurred in a young girl with neurologic problems and a kyphoscoliosis operated on in laparoscopy for a gastroesophageal reflux is discussed. After the establishment of pneumoperitoneum, an important hemoperitoneum was rapidly evident at insertion of the laparoscope. An open laparotomy was performed showing right common iliac vessel injuries and several intestinal perforations. After a complex vascular reconstruction and a multiple intestinal suture, the Nissen fundoplication with pyloroplasty was performed traditionally and the patient leave the hospital free of symptoms after 20 days. In laparoscopy, as in all areas of surgery, experience knowledge and meticulous attention to details are the most important factors in order to avoid complications. The authors believe that the open approach with Hasson cannula is the most important factor in avoiding complications.

Absence of the cell cycle inhibitor p27Kip1 protein predicts poor outcome in patients with stage I-III colorectal cancer

BACKGROUND

The p27Kip1 protein regulates the G1 to S phase transition of cell cycle by binding to and inhibiting the cyclin E/Cdk2 complex. This study explores the prognostic significance of the absence of the p27Kip1 protein in patients with colorectal cancer (CRC).

METHODS

Formalin-fixed tumor sections from 124 patients who underwent curative resection for stage I-III CRC were analyzed by immunohistochemistry using MoAb anti-p27KiP1.

RESULTS

Detectable levels of p27Kip1 protein were found in 86% of tumors. Median follow-up was 55 months. Actuarial 5-year disease-free survival (DFS) and overall survival (OS) were 76% and 85%, respectively, in patients with tumors with p27Kip1 protein expression and 34% and 40%, respectively, in those whose tumors lacked p27Kip1 protein expression (P < .001). At multivariate analysis, tumor stage (III vs. I-II) and p27Kip1 protein status (absence vs. presence) were found to be independent prognostic factors for DFS and OS.

CONCLUSIONS

Lack of p27KiP1 protein expression in CRC is a negative prognostic marker and may therefore be useful in selecting early-stage patients more likely to benefit from adjuvant treatment.