Identification of a novel X-linked gene responsible for Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy (EDMD) is an X-linked recessive disorder characterized by slowly progressing contractures, wasting of skeletal muscle and cardiomyopathy. Heart block is a frequent cause of death. The disease gene has been mapped to distal Xq28. Among many genes in this region, we selected eight transcripts expressed at high levels in skeletal muscle, heart and/or brain as the best candidates for the disease. We now report, in all five patients studied, unique mutations in one of the genes, STA: these mutations result in the loss of all or part of the protein. The EDMD gene encodes a novel serine-rich protein termed emerin, which contains a 20 amino acid hydrophobic domain at the C terminus, similar to that described for many membrane proteins of the secretory pathway involved in vesicular transport.

The caspase-3 precursor has a cytosolic and mitochondrial distribution: implications for apoptotic signaling

Caspase-3-mediated proteolysis is a critical element of the apoptotic process. Recent studies have demonstrated a central role for mitochondrial proteins (e.g., Bcl-2 and cytochrome c) in the activation of caspase-3, by a process that involves interaction of several protein molecules. Using antibodies that specifically recognize the precursor form of caspase-3, we demonstrate that the caspase-3 proenzyme has a mitochondrial and cytosolic distribution in nonapoptotic cells. The mitochondrial caspase-3 precursor is contained in the intermembrane space. Delivery of a variety of apoptotic stimuli is accompanied by loss of mitochondrial caspase-3 precursor staining and appearance of caspase-3 proteolytic activity. We propose that the mitochondrial subpopulation of caspase-3 precursor molecules is coupled to a distinct subset of apoptotic signaling pathways that are Bcl-2 sensitive and that are transduced through multiple mitochondrion-specific protein interactions.

Obesity and cardiac function

We studied 10 obese volunteers, mean age 36.5 +/- 10.3 years, who weighed 123.56 +/- 28.7 g and were 69.96 +/- 22.5 kg overweight. The subjects did not have diabetes, arterial hypertension or signs of cardiac and respiratory failure or disease and all underwent right- and left-heart catheterization. cardiac output and stroke volume were high, according to increased oxygen consumption and to the degree of obesity. Ventricular end-diastolic and atrial pressures ranged from normal to high and correlated with body weight, signs of volume overloading and reduced left ventricular (LV) compliance. The mean pulmonary artery pressure was elevated and correlated well with weight, pulmonary resistance being normal; mean aortic pressure did not correlate with weight, and systemic arterial resistance tended to have a negative correlation. The LV function curve showed impaired ventricular function, particularly for the heaviest subjects, in whom Vmax and the ratio of the stroke work index to LV end-diastolic pressure were reduced. These indexes correlated well with each other and both correlated negatively with the degree of obesity. In contrast, maximal dP/dt was normal and did not correlate with excess weight. These observations show that depressed LV function is already present in relatively young obese people, even if they are free from signs of cardiopathy and other associate diseases. The degree of impairment of heart function seems to parallel the degree of obesity.

Mitochondrial proliferation and paradoxical membrane depolarization during terminal differentiation and apoptosis in a human colon carcinoma cell line

Herbimycin A, a tyrosine kinase inhibitor, induces cellular differentiation and delayed apoptosis in Colo-205 cells, a poorly differentiated human colon carcinoma cell line. Cell cycle analysis in conjunction with end labeling of DNA fragments revealed that G2 arrest preceded apoptotic cell death. Ultrastructural examination of herbimycin-treated cells demonstrated morphologic features of epithelial differentiation, including formation of a microvillar apical membrane and lateral desmosome adhesions. A marked accumulation of mitochondria was also observed. Fluorometric analysis using the mitochondrial probes nonyl-acridine orange and JC-1 confirmed a progressive increase in mitochondrial mass. However these cells also demonstrated a progressive decline in unit mitochondrial transmembrane potential (DeltaPsim) as determined by the DeltaPsim-sensitive fluorescent probes rhodamine 123 and JC-1 analyzed for red fluorescence. In concert with these mitochondrial changes, Colo-205 cells treated with herbimycin A produced increased levels of reactive oxygen species as evidenced by oxidation of both dichlorodihydrofluorescein diacetate and dihydroethidium. Cell-free assays for apoptosis using rat-liver nuclei and extracts of Colo-205 cells at 24 h showed that apoptotic activity of Colo-205 lysates requires the early action of mitochondria. Morphological and functional mitochondrial changes were observed at early time points, preceding cleavage of poly (ADP-ribose) polymerase. These results suggest that apoptosis in differentiated Colo-205 cells involves unrestrained mitochondrial proliferation and progressive membrane dysfunction, a novel mechanism in apoptosis.

Body-worn motion sensors detect balance and gait deficits in people with multiple sclerosis who have normal walking speed

While balance and gait limitations are hallmarks of multiple sclerosis (MS), standard stopwatch-timed measures practical for use in the clinic are insensitive in minimally affected patients. This prevents early detection and intervention for mobility problems. The study sought to determine if body-worn sensors could detect differences in balance and gait between people with MS with normal walking speeds and healthy controls. Thirty-one MS and twenty-eight age- and sex-matched control subjects were tested using body-worn sensors both during quiet stance and gait (Timed Up and Go test, TUG). Results were compared to stopwatch-timed measures. Stopwatch durations of the TUG and Timed 25 Foot Walk tests were not significantly different between groups. However, during quiet stance with eyes closed, people with MS had significantly greater sway acceleration amplitude than controls (p=0.02). During gait, people with MS had greater trunk angular range of motion in roll (medio-lateral flexion, p=0.017) and yaw (axial rotation, p=0.026) planes. Turning duration through 180° was also longer in MS (p=0.031). Thus, body-worn motion sensors detected mobility differences between MS and healthy controls when traditional timed tests could not. This portable technology provides objective and quantitative mobility data previously not obtainable in the clinic, and may prove a useful outcome measure for early mobility changes in MS.

DNA-mediated immunization to the hepatitis B surface antigen in mice: aspects of the humoral response mimic hepatitis B viral infection in humans

Intramuscular injection of plasmid DNA expression vectors encoding the three envelope proteins of the hepatitis B virus (HBV) induced humoral responses in C57BL/6 mice specific to several antigenic determinants of the viral envelope. The first antibodies appeared within 1-2 weeks after injection of DNA and included antibodies of the IgM isotype. Over the next few weeks, an IgM to IgG class switch occurred, indicating helper T-lymphocyte activity. Peak IgG titers were reached by 4-8 weeks after a single DNA injection and were maintained for at least 6 months without further DNA injections. The antibodies to the envelope proteins reacted with group- and subtype-specific antigenic determinants of the HBV surface antigen (HBsAg). Expression vectors encoding the major (S) and middle (preS2 plus S) envelope proteins induced antibodies specific to the S protein and preS2 domain, and preS2 antibodies were prominent at early time points. In general, the expression vectors induced humoral responses in mice that mimic those observed in humans during the course of natural HBV infection.

Human CD4+ T cells specifically recognize a shared melanoma-associated antigen encoded by the tyrosinase gene

Although commonly expressed human melanoma-associated antigens recognized by CD8+ cytolytic T cells have been described, little is known about CD4+ T-cell recognition of melanoma-associated antigens. Epstein-Barr virus-transformed B cells were used to present antigens derived from whole cell lysates of autologous and allogeneic melanomas for recognition by melanoma-specific CD4+ T-cell lines and clones cultured from tumor-infiltrating lymphocytes. HLA-DR-restricted antigens were detected in the lysates on the basis of specific release of cytokines from the responding T cells. Antigen sharing was demonstrated in the majority of melanomas tested, as well as in cultured normal melanocytes, but not in other normal tissues or nonmelanoma tumors. T-cell clones manifested a single recognition pattern, suggesting the presence of an immunodominant epitope. This epitope was identified as a product of the tyrosinase gene, which has also been shown to encode class I-restricted epitopes recognized by CD8+ T cells from melanoma patients. Identification of commonly expressed tumor-associated protein molecules containing epitopes presented by both class I and class II major histocompatibility molecules may provide optimal reagents for cancer immunization strategies.

Pravastatin reduces carotid intima-media thickness progression in an asymptomatic hypercholesterolemic mediterranean population: the Carotid Atherosclerosis Italian Ultrasound Study

PURPOSE

The Carotid Atherosclerosis Italian Ultrasound Study (CAIUS) was performed to test the effects of lipid lowering on the progression of carotid intima-media thickness (IMT) in 305 asymptomatic patients from a Mediterranean country.

PATIENTS AND METHODS

Eligibility included hypercholesterolemia (baseline means: low-density lipoprotein [LDL] = 4.68 mmol/L, high-density lipoprotein [HDL] = 1.37 mmol/L), and at least one 1.3 < IMT < 3.5 mm in the carotid arteries. Patients (mean age 55 years, 53% male) were assigned to pravastatin (40 mg/day, n = 151) or placebo (n not equal to 154). Ultrasound imaging was used to quantify IMT at baseline, and semiannually thereafter for up to 3 years. The mean of the 12 maximum IMTs (MMaxIMT), was calculated for each patient visit, and used to determine each patient's longitudinal progression slope. The intention-to-treat group difference in the MMaxIMT progression was chosen a priori as the primary end point.

RESULTS

Five serious cardiovascular events (1 fatal myocardial infarction), and 7 drop-outs for cancer were registered. In the pravastatin group, LDL decreased -0.22 after 3 months versus -0.01 in the placebo group, and remained substantially unchanged afterward (-0.23 versus +0.01 at 36 months, respectively). Progression of the MMaxIMT was 0.009 +/- 0.0027 versus -0.0043 +/- 0.0028 mm/year (mean +/- SE, P < 0.0007) in the placebo and pravastatin groups, respectively. IMT progression slopes diverged after 6 months of treatment.

CONCLUSIONS

Pravastatin stops the progression of carotid IMT in asymptomatic, moderately hypercholesterolemic men and women. This finding extends the beneficial effects of cholesterol lowering to the primary prevention of atherosclerosis in a population with relatively low cardiovascular event rates, and suggests that this benefit is mediated by specific morphological effects on early stages of plaque development.

Annexin V binds to viable B cells and colocalizes with a marker of lipid rafts upon B cell receptor activation

Recombinant annexin V (rAnV) has been used to identify apoptotic cells based on its ability to bind phosphatidylserine (PS), a lipid normally restricted to the cytoplasmic face of the plasma membrane, but externalized early during apoptosis. However, this association of rAnV binding and apoptosis is not an obligatory one. We demonstrate that rAnV binds to a large fraction of murine B cells bearing selectable Ag receptors despite the fact that these cells are not apoptotic. Phosphatidylserine, which is uniformly distributed on resting B cells, is mobilized to co-cap with IgM on anti-IgM-treated B cells and to colocalize with GM1, a marker of lipid rafts. Cross-linking PS before anti-IgM treatment sequesters this lipid and alters signaling through IgM. Thus, PS exposed on the majority of B cells in vivo does not reflect early apoptosis, but, instead, plays a role in receptor-mediated signaling events.

Functionally thrombasthenic state in normal platelets following the administration of ticlopidine

To elucidate the bleeding tendency that follows the administration of ticlopidine, we investigated the skin bleeding time and some ex vivo functions of platelets obtained from eight healthy volunteers before and 1 wk after daily administration of 500 mg of ticlopidine. We found the following: ticlopidine significantly (P less than 0.001) prolonged the skin bleeding time and impaired the binding of radiolabeled fibrinogen and von Willebrand Factor, the clot retraction and the aggregation of platelets in response to ADP, epinephrine, thrombin, ionophore A23187, collagen, or arachidonic acid. In contrast, the administration of this drug did not affect intraplatelet levels of cAMP, agglutination and binding of von Willebrand Factor in response to ristocetin, shape change in response to ADP, collagen, thrombin, or arachidonic acid, or binding of prostaglandin E1 to resting platelets. Secretion of ATP in response to ADP or epinephrine was completely inhibited, whereas secretion as well as thromboxane synthesis in response to high concentrations of collagen, arachidonic acid, calcium ionophore A23187, or thrombin was unaffected. Studies with monoclonal antibodies showed that the glycoprotein IIb-IIIa complex (the putative receptor for fibrinogen and von Willebrand Factor on the surface of platelets exposed to naturally occurring aggregating agents) was quantitatively unaffected by ticlopidine. This observation was further confirmed by densitometric scannings of Periodic Acid-Schiff-stained gels of platelet suspensions. The onset, as well as the cessation of the inhibitory effect of ticlopidine on platelets was very slow, and reached a maximum after a 3-5-d administration. In addition, ticlopidine appeared to be a much more potent inhibitor when administered to subjects than when added in vitro to platelets. Finally, abnormalities comparable to those found in volunteers taking ticlopidine were observed when platelets from untreated subjects were incubated in the plasma of ticlopidine-treated subjects. We conclude that ticlopidine induces a thrombasthenic state in normal platelets without affecting the glycoprotein IIb-IIIa complex quantitatively. Furthermore, our data suggest that one or more active metabolites rather than the native drug mediate the abnormalities of platelet function observed in ticlopidine-treated subjects.

Abnormalities of calcium metabolism in essential hypertension

Calcium metabolism has been investigated in patients with essential hypertension and normal renal function to evaluate the renal calcium handling and the reported increase in renal calcium loss. In 55 hypertensive and 55 sex- and age-matched healthy normotensive subjects creatinine clearance, serum total and ionized calcium, plasma parathyroid hormone and 24 h urinary excretion of calcium, sodium and cAMP were measured. In a subgroup of 20 hypertensive patients and 20 controls the fasting calcium excretion rate was also measured. Both 24 h and fasting calcium excretion rates were higher in the hypertensive group; so also were plasma parathyroid hormone and urinary cAMP. Serum total and ionized calcium levels were not different in the two groups. After intravenous calcium infusion (15 mg 3 h-1 kg-1) in seven hypertensive patients and controls, the hypertensive patients excreted more calcium at all serum calcium concentrations. These results support the hypothesis of primary renal calcium leak in essential hypertension. Enhanced urinary calcium excretion rate may cause compensatory parathyroid overactivity.

Molecular profiling of blastic plasmacytoid dendritic cell neoplasm reveals a unique pattern and suggests selective sensitivity to NF-kB pathway inhibition

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare disease of controversial origin recently recognized as a neoplasm deriving from plasmacytoid dendritic cells (pDCs). Nevertheless, it remains an orphan tumor with obscure biology and dismal prognosis. To better understand the pathobiology of BPDCN and discover new targets for effective therapies, the gene expression profile (GEP) of 25 BPDCN samples was analyzed and compared with that of pDCs, their postulated normal counterpart. Validation was performed by immunohistochemistry (IHC), whereas functional experiments were carried out ex vivo. For the first time at the molecular level, we definitely recognized the cellular derivation of BPDCN that proved to originate from the myeloid lineage and in particular, from resting pDCs. Furthermore, thanks to an integrated bioinformatic approach we discovered aberrant activation of the NF-kB pathway and suggested it as a novel therapeutic target. We tested the efficacy of anti-NF-kB-treatment on the BPDCN cell line CAL-1, and successfully demonstrated by GEP and IHC the molecular shutoff of the NF-kB pathway. In conclusion, we identified a molecular signature representative of the transcriptional abnormalities of BPDCN and developed a cellular model proposing a novel therapeutic approach in the setting of this otherwise incurable disease.

DNA-mediated immunization to hepatitis B surface antigen: longevity of primary response and effect of boost

Intramuscular (i.m.) injection of mice with plasmid DNA expression vectors containing all or part of the hepatitis B virus (HBV) gene encoding the envelope proteins induces a strong humoral response to the HBV surface antigen (HBsAg) which is sustained for up to 74 weeks without boost. After a single i.m. injection of 100 micrograms DNA, antibodies to HBsAg (anti-HBs) reach ELISA titers of 4 x 10(4) in C57BL/6 mice and 10(4) in BALB/c mice, or somewhat less in older mice. Although antibody levels induced by a single injection of DNA do not diminish significantly over time, they can be further increased 10-200-fold by boosting with a second injection of DNA or an injection of recombinant HBsAg protein. Prior injection of DNA does not affect the strength or timing of the boosting effect, suggesting that there is no immune response against the vector itself. Boosting with a second injection of DNA is possible even in BALB/c mice, which are known to have a strong cytotoxic T-lymphocyte response against an epitope on the major HBV envelope protein, indicating that possible destruction of newly transfected muscle fibers is not so quick and efficient as to abort the boosting effect. A single injection of DNA results in a stronger and longer lasting humoral response than does a single injection of recombinant protein.

Specific vaccine therapy in chronic hepatitis B: induction of T cell proliferative responses specific for envelope antigens

In a pilot study, it was established that specific therapy by standard anti-hepatitis B virus (HBV) vaccination may be effective in reducing HBV replication and canceling the immune tolerance to hepatitis B surface antigen (HBsAg) particles in about 50% of persons with chronic active HBV replication. In the present study, the vaccine-induced immune responses were analyzed during an ongoing controlled multicenter vaccine trial. Vaccination elicited peripheral blood mononuclear cell proliferative responses specific for envelope antigen in 7 of 27 subjects given HBsAg. The responses induced by the vaccines were mediated by CD4+ T lymphocytes, and at least three different epitopes were recognized. HBV-specific CD4+ T lymphocytes produced high levels of interferon-gamma [corrected] and belonged to a T helper 1 subset. Reduction of serum HBV DNA in some of these persons suggests that induction of CD4+ T cell responses could be important in controlling viremia during vaccine therapy of chronic HBV carriers.

Long-term effects of fish oil on insulin resistance and plasma lipoproteins in NIDDM patients with hypertriglyceridemia

OBJECTIVE

The aim of this study was to evaluate the long-term (6-month) effects of moderate fish oil supplementation on insulin sensitivity and plasma lipoproteins in NIDDM patients with hypertriglyceridemia.

RESEARCH DESIGN AND METHODS

The study has been performed according to a randomized double-blind placebo-controlled design with a parallel group sequence. After a washout period of 4 weeks and a run-in period of 3 weeks, 16 NIDDM patients with hypertriglyceridemia (triglyceride [TG], 2.25-5.65 mmol/l) were randomly assigned to either fish oil (2.7 g/day eicosapentaenoic plus docosahexaenoic acid for 2 months, then 1.7 g/day for 4 more months) (n = 8) or placebo (n = 8). Diet and hypoglycemic drugs remained unchanged throughout the whole experiment. At baseline and after 6 months, insulin sensitivity was measured by euglycemic hyperinsulinemic clamp (insulin infused, 2.0 mIU.kg-1 body wt.min-1). At the same time, blood glucose control, fasting and postprandial serum insulin and nonesterified fatty acid (NEFA) concentrations, and fasting plasma lipoprotein concentrations were evaluated.

RESULTS

In the group treated with fish oil compared with the baseline, there was: 1) a significant reduction in both plasma TG (2.92 +/- 0.23 vs. 3.85 +/- 0.32 [mean +/- SE] mmol/l, P < 0.001) and VLDL-TG (2.35 +/- 0.24 vs. 4.25 +/- 0.66 mmol/l, P < 0.01), without significant changes in blood glucose control; 2) a significant reduction in fasting NEFA concentrations (572 +/- 100 vs. 825 +/- 131 mumol/l, P < 0.01); and 3) a significant enrichment in long-chain omega-3 fatty acids of erythrocyte membrane phospholipids. In the placebo group, there were no changes in any of the variables analyzed. The insulin-mediated glucose uptake was unchanged in both groups (fish oil, 4.04 +/- 0.82 mg.kg-1.min-1 at baseline and 3.96 +/- 0.50 mg.kg-1.min-1 at 6 months; placebo, 3.51 +/- 0.62 mg.kg-1.min-1 at baseline and 4.09 +/- 0.49 mg.kg-1.min-1 at 6 months).

CONCLUSIONS

In NIDDM patients with hypertriglyceridemia, moderate amounts of fish oil induce a long-term significant reduction in plasma triglycerides, VLDL triglycerides, and NEFA and a significant enrichment in the erythrocyte phospholipid content of long-chain omega-3 fatty acids, without deteriorating blood glucose control. However, this amount of omega-3 fatty acids was unable to improve insulin sensitivity in this group of patients.

DNA-mediated immunization in a transgenic mouse model of the hepatitis B surface antigen chronic carrier state

Transgenic mice expressing the sequences coding for the envelope proteins of the hepatitis B virus (HBV) in the liver have been used as a model of the HBV chronic carrier state. We evaluated the possibility of inducing a specific immune response to the viral envelope antigens and thus potentially controlling chronic HBV infection. Using HBV-specific DNA-mediated immunization in this transgenic model, we show that the immune response induced after a single intramuscular injection of DNA resulted in the complete clearance of circulating hepatitis B surface antigen and in the long-term control of transgene expression in hepatocytes. This response does not involve a detectable cytopathic effect in the liver. Adoptive transfer of fractionated primed spleen cells from DNA-immunized mice shows that T cells are responsible for the down-regulation of HBV mRNA in the liver of transgenic mice. To our knowledge, this is the first demonstration of a potential immunotherapeutic application of DNA-mediated immunization against an infectious disease and raises the possibility of designing more effective ways of treating HBV chronic carriers.

rab8 in retinal photoreceptors may participate in rhodopsin transport and in rod outer segment disk morphogenesis

Small GTP-binding protein rab8 regulates transport from the TGN to the basolateral plasma membrane in epithelial cells and to the dendritic plasma membrane in cultured hippocampal neurons. In our approach to identify proteins involved in rhodopsin transport and sorting in retinal photoreceptors, we have found, using [32P]GTP overlays of 2D gel blots, that six small GTP-binding proteins are tightly bound to the post-Golgi membranes immunoisolated with a mAb to the cytoplasmic domain of frog rhodopsin. We report here that one of these proteins is rab8. About 50% of photoreceptor rab8 is membrane associated and approximately 13% is tightly bound to the post-Golgi vesicles. By confocal microscopy, antibody to rab8 specifically labels calycal processes and the actin bundles of the photoreceptor inner segment that extend inward to the junctional complexes that comprise the outer limiting membrane. Anti-rab8 shows a striking periodicity of high density labeling at 1 +/- 0.12 microns intervals along the actin bundles. Rhodopsin-bearing post-Golgi membranes cluster around the base of the cilium where rab8 and actin are also co-localized, as revealed by confocal microscopy of retinal sections double labeled with anti-rab8 and phalloidin. Microfilaments have been implicated in rod outer segment (ROS) disk morphogenesis. Our data suggest that rab6, which we have previously localized to the post-Golgi compartment, and rab8 associate with the post-Golgi membranes sequentially at different stages of transport. rab8 may mediate later steps that involve interaction of transport membranes with actin filaments and may participate in microfilament-dependent ROS disk morphogenesis.

In vivo ultrasound assessment of respiratory function of abdominal muscles in normal subjects

Ultrasonography has recently been proposed for assessing changes in thickness and motion of the diaphragm during contraction in humans. Data on ultrasound assessment of abdominal muscles in humans are scarce. We therefore investigated the changes in thickness and the relevant mechanical effects of abdominal muscles using this technique during respiratory manoeuvres in normal subjects. We evaluated the thickness of the abdominal muscle layers in six normal male subjects (aged 26-36 yrs) using a 7.5 MHz B-mode ultrasound transducer. Gastric (Pg) and mouth pressures, muscle thickness of external oblique (EO), internal oblique (IO), transversus abdominis (TA) and rectus abdominis (RA) were assessed at functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), during progressive (PEEs) and maximal expiratory efforts (MEEs) against a closed airway and during homolateral (HTR) and contralateral (CTR) trunk rotation. Abdominal muscle thickness was found to be reproducible (coefficient of variation and two-way analysis of variance). Compared to FRC, the thickness of IO, TA and RA significantly increased at RV and during MEEs, whereas EO remained unchanged; at TLC, the thickness of IO and TA significantly decreased. During PEEs, a significant relationship between increase in Pg and TA thickness was observed in all subjects, the thickness of the other abdominal muscles being inconsistently related to Pg. Finally, a significant increase in the thickness of IO and EO was found during HTR and CTR, respectively. We conclude that during maximal expiratory manoeuvres, transversus abdominis, internal oblique and rectus abdominis thickened similarly. Transversus abdominis seems to be the major contributor in generating abdominal expiratory pressure during progressive expiratory efforts. External oblique seems to be preferentially involved during trunk rotation. These results suggest the possible value of studying the abdominal muscles by ultrasonography in various respiratory disorders.

Anticipatory postural adjustments prior to step initiation are hypometric in untreated Parkinson's disease: an accelerometer-based approach

BACKGROUND AND PURPOSE

Anticipatory postural adjustments (APAs), prior to step initiation, are bradykinetic in advanced Parkinson's disease (PD) and may be one of the factors associated with 'start hesitation'. However, little is known about APAs in the early stage of PD. In this study, we determined whether body-worn accelerometers could be used to characterize step initiation deficits in subjects with early-to-moderate, untreated PD.

METHODS

Eleven PD and 12 healthy control subjects were asked to take two steps. Postural adjustments were compared from center of pressure (COP) and from acceleration of the trunk at the center of mass level (L5).

RESULTS

Our findings show that APAs measured from the peak COP displacement toward the swing leg and the peak trunk acceleration toward the stance leg were smaller in untreated PD compared with control subjects. The magnitude of APAs measured from peak COP displacements and accelerations were correlated.

CONCLUSION

These results suggest that quantitative analysis of step initiation from one accelerometer on the trunk could provide useful information for the characterization of patients in early stages of PD, when clinical evidence of start hesitation may not be detectable. Ambulatory monitoring of step initiation is also promising for monitoring patient progression in the home environment, and eventually providing feedback for preventing freezing of gait episodes.

Direct gene transfer in skeletal muscle: plasmid DNA-based immunization against the hepatitis B virus surface antigen

Direct gene transfer by intramuscular injection of plasmid DNA encoding an antigenic protein may be used for the purpose of immunization. DNA-based immunization may be of value for basic immunological research and vaccine development. Several factors influence the uptake and expression of plasmid DNA in skeletal muscle, which in turn influence the immune response to the expressed protein. Physical barriers and other factors may impede diffusion of the DNA within the muscle tissue or its entry into the muscle fibres. Although the efficiency of gene transfer in normal mouse muscle is low (< 100 fibres per injection site), a humoral response to the hepatitis B surface antigen (HBsAg) is obtained after expression of a transferred gene. Direct gene transfer is ten times more efficient in regenerating than in normal mouse muscle. DNA-based immunization in such regenerating muscles results in an earlier and stronger humoral response to HBsAg than is seen in normal mature muscle. A needleless jet injection system (Biojector) is able to deliver DNA into normal muscle in rats and rabbits such that a substantial immune response is obtained.

Flow cytometric detection of HLA-specific antibodies as a predictor of heart allograft rejection

BACKGROUND

Historically, panel reactive antibody (PRA) analysis to detect HLA antibodies has been performed using cell-based complement-dependent cytotoxicity (CDC) techniques. Recently, a flow cytometric procedure (FlowPRA) was introduced as an alternative approach to detect HLA antibodies. The flow methodology, using a solid phase matrix to which soluble HLA class I or class II antigens are attached is significantly more sensitive than CDC assays. However, the clinical relevance of antibodies detected exclusively by FlowPRAhas not been established. In this study of cardiac allograft recipients, FlowPRA was performed on pretransplant sera with no detectable PRA activity as assessed by CDC assays. FlowPRA antibody activity was then correlated with clinical outcome.

METHODS

PRA analysis by anti-human globulin enhanced (AHG) CDC and FlowPRA was performed on sera corresponding to final cross-match specimens from 219 cardiac allograft recipients. In addition, sera collected 3-6 months posttransplant from 91 patients were evaluated. The presence or absence of antibodies was correlated with episodes of rejection and patient survival. A rejection episode was considered to have occurred based on treatment with antirejection medication and/or histology.

RESULTS

By CDC, 12 patients (5.5%) had pretransplant PRA >10%. In contrast, 72 patients (32.9%) had pretransplant anti-HLA antibodies detectable by FlowPRA (34 patients with only class I antibodies; 7 patients with only class II antibodies; 31 patients with both class I and class II antibodies). A highly significant association (P<0.001) was observed between pretransplant HLA antibodies detected by FlowPRA and episodes of rejection that occurred during the first posttransplant year. Fifteen patients died within the first year posttransplant. Of nine retrospective flow cytometric cross-matches that were performed, two were in recipients who had no pretransplant antibodies detectable by FlowPRA. Both of these cross-matches were negative. In contrast, five of seven cross-matches were positive among recipients who had FlowPRA detectable pretransplant antibodies. Posttransplant serum specimens from 91 patients were also assessed for antibodies by FlowPRA. Among this group, 58 patients had FlowPRA antibodies and there was a trend (although not statistically significant) for a biopsy documented episode of rejection to have occurred among patients with these antibodies.

CONCLUSIONS

Collectively, our data suggest that pre- and posttransplant HLA antibodies detectable by FlowPRA and not AHG-CDC identify cardiac allograft recipients at risk for rejection. Furthermore, a positive donor reactive flow cytometric cross-match is significantly associated with graft loss. Thus, we believe that detection and identification of HLA-specific antibodies can be used to stratify patients into high and low risk categories. An important observation of this study is that in the majority of donor:recipient pairs, pretransplant HLA antibodies were not directed against donor antigens. We speculate that these non-donor-directed antibodies are surrogate markers that correspond to previous T cell activation. Thus, the rejection episodes that occur in these patients are in response to donor-derived MHC peptides that share cryptic determinants with the HLA antigens that initially sensitized the patient.

Low glomerular filtration in the population: Prevalence, associated disorders, and awareness

Estimated glomerular filtration rate (eGFR) was used for analysis of kidney disease prevalence in the United States. The study investigated on prevalence, associated disorders, and kidney disease awareness in an Italian population sample. Data were collected on serum creatinine, other laboratory indices, blood pressure, and medical history in the Gubbio Population Study (n=4574, both sexes, ages 18-95 years). Analyses were carried out on eGFR (equation of Modification Diet in Renal Disease study), disorders potentially secondary to kidney dysfunction (hypertension, high serum uric acid, high serum phosphorus/low serum calcium, high serum potassium, cardiovascular disease, anemia), and kidney disease awareness. The prevalence of eGFR <60 ml/min x 1.73 m(2) increased with age in both sexes (from <1% for ages 18-24 years to >30% for ages > or =75 years, P<0.001). In the group with eGFR <60 ml/min x 1.73 m(2), number of disorders secondary to kidney dysfunction was > or =2 in the majority of persons, was higher than in persons with eGFR > or =60 ml/min x 1.73 m(2) (P<0.001), and was inversely related to eGFR (P<0.001). The prevalence of reported kidney disease was 3.3% in the group with eGFR <60 ml/min x 1.73 m(2) and directly related to serum creatinine and number of disorders secondary to kidney dysfunction (P<0.001). Low kidney function is frequent in the older population and is associated with disorders typical of kidney disease. Persons with low kidney function are rarely aware of kidney disease unless of very high serum creatinine or presence of many disorders typical of kidney disease.

Kidney stones and hypertension: population based study of an independent clinical association

OBJECTIVE

To test the hypothesis that kidney stone disease is more frequent among hypertensive men when the effect of possible confounders is allowed for.

DESIGN

Cross sectional study of a sample of the male working population conducted as part of the 10 year follow up of a nationwide survey of the prevalence of cardiovascular risk factors.

SETTING

The Olivetti factory in Pozzuoli, a suburban area of Naples.

POPULATION

688 Male workers (87.9% of the male workforce) aged 21-68.

INTERVENTIONS

Anthropometric and blood pressure measurements, blood tests, and administration of a detailed questionnaire aimed at detecting a history of urolithiasis.

MAIN OUTCOME MEASURES

Prevalence of a history of urolithiasis among normotensive and untreated and treated hypertensive men adjusted for the possible confounding effects of age, body mass index, renal function, and serum urate and total calcium concentrations.

RESULTS

Of the 688 participants 509 were normotensive. Of the remainder, 118 had untreated and 61 treated hypertension. The overall prevalence of a history of urolithiasis was 16.3% (112/688). The relative risk of hypertensive subjects having a history of kidney stones was twice that of the normotensive group (odds ratio 2.11; 95% confidence interval 1.17 to 3.81), the risk being higher when only treated hypertensives were considered (odds ratio 3.16; 95% confidence interval 1.75 to 5.71). The prevalence of a history of urolithiasis was 13.4% (68/509) in the normotensive subjects, 20.3% (24/118) in the untreated hypertensives, and 32.8% (20/61) in the treated hypertensives (p less than 0.001). The age adjusted relative risk in treated hypertensive men was higher than that in the normotensive group (Mantel-Haenszel pooled estimate of odds ratio 2.63; 95% confidence interval 2.23 to 3.10).

CONCLUSION

An independent clinical association exists between the occurrence of urolithiasis and hypertension. The increased urinary calcium excretion commonly detected in hypertension may be the pathogenetic link.