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Nirupama Sabnis1, Maya Nair1, Mervyn Israel2, Walter J McConathy3, Andras G Lacko11University of North Texas Health Science Center, Fort Worth, TX, 2University of Tennessee Health Science Center, Memphis, TN, 3Texas Tech University Health Sciences Center–Permian Basin, Odessa, TX, USAAbstract: Among numerous drug-delivery approaches, reconstituted high-density lipoprotein (rHDL) nanocarriers have proven particularly applicable for delivering highly hydrophobic drugs. In this study, we have investigated the enhancement of the therapeutic impact of valrubicin (AD-32), an antineoplastic agent that has been limited to intravesicular application against bladder cancer, despite the encouraging original preclinical data. Earlier studies validated the superior therapeutic efficacy of AD-32 over doxorubicin. In the present study, rHDL/AD-32 nanoparticles were formulated and characterized with regard to encapsulation efficiency, physicochemical properties, selective toxicity, and receptor-mediated uptake. The half maximal inhibitory concentration values (IC50) for rHDL/AD-32 nanoparticles were 1.8 and 2.6 times lower than the free AD-32 for prostate (PC-3) and ovarian (SKOV-3) cancer cell lines, respectively, whereas nonmalignant cell lines demonstrated 5 and 1.48 times higher IC50 doses with rHDL/AD-32 formulations. The data obtained demonstrated effective receptor-mediated uptake of AD-32 from the rHDL nanocarriers by PC-3 and SKOV-3 cancer cells via a targeted drug-delivery process. The rHDL/AD-32 formulation was stable for 6 months when stored at 4°C or at –20°C, as 92% of the AD-32 was retained in the nanoparticles. The findings from this study show that the rHDL/AD-32 formulation can overcome the solubility barriers of AD-32 and thus serve as an effective systemically administered chemotherapeutic agent.Keywords: AD-32, rHDL, nanoparticles, targeted drug delivery, selective drug delivery

Objective. Assess the prevalence of abnormal glucose metabolism among Hispanic parents of children with acanthosis nigricans (AN). Methods. Hispanic families (n=258) were evaluated for metabolic and anthropometric parameters including fasting glucose levels and AN status. Results. Mothers with AN+ children had IFG (17.3%) and 4% had glucose levels ≥126 mg/dL (P=0.028) compared to 7.1% and 1.8% of mothers with AN− children, respectively. Mothers of AN+ children also had greater odds of having impaired fasting glucose levels (OR: 3.917, 95% CI: 1.475–10.404; P<0.004) but this was not the case for fathers (OR: 1.125, 95% CI: 0.489–2.586; P=0.781). Mothers of AN+ children were also more likely to be AN+ (OR: 5.76, 95% CI: 2.98–11.13, P<0.001). Screening discovered glucose levels >126 mg/dL in 9% of fathers with AN+ children. Conclusions. Hispanic mothers of AN+ children are at higher risk of carbohydrate metabolism abnormalities. AN in children can be a marker for prevention and delay programs aimed at identifying adults at risk for diabetes.

The purpose of these studies was to determine the mechanism(s) whereby paclitaxel (PTX), is taken up by cancer cells, once encapsulated into synthetic/reconstituted high density lipoprotein (rHDL). The uptake of PTX was found to be facilitated by the scavenger receptor type B-1 (SR-B1) when drug-loaded rHDL particles were incubated with cells that express the SRB1 receptor. Studies with double-labeled, PTX containing rHDL nanoparticles showed that prostate cancer (PC-3) cells incorporated PTX primarily via a selective (SR-B1 type) uptake mechanism. In the presence of a 10-fold excess of plasma HDL, PTX uptake decreased to 30% of the control. These findings suggest that the incorporation of lipophilic drugs by cancer cells from rHDL nanoparticles is facilitated by a receptor mediated (SR-B1) mechanism.

Reconstituted (synthetic) high-density lipoprotein particles carrying paclitaxel (rHDL/PTX) were prepared with substantially higher PTX content than reported earlier. The rHDL/PTX complexes seemed to be primarily spherical nanoparticles when examined via electron microscopy, with a constant composition, molecular weight and exceptional stability even after ultracentrifugation and storage for up to 6 months. The rHDL/PTX nanoparticles had superior cytotoxicity against several cancer cell lines (MCF7, DU145, OV1063 and OVCAR-3), the half maximal inhibitory concentration (IC50) having been found to be 5-20 times lower than that of the free drug. Studies with mice showed that the rHDL/PTX nanoparticles were substantially better tolerated than the corresponding dosages of either Taxol or Abraxane.

This review is intended to evaluate the research findings and potential clinical applications of drug transport systems, developed based on the concepts of the structure/function and physiological role(s) of high density lipoprotein type nanoparticles. These macromolecules provide targeted transport of cholesteryl esters (a highly lipophilic payload) in their natural/physiological environment. The ability to accommodate highly water insoluble constituents in their core regions enables High density lipoproteins (HDL) type nanoparticles to effectively transport hydrophobic drugs subsequent to systemic administration. Even though the application of reconstituted HDL in the treatment of a number of diseases is reviewed, the primary focus is on the application of HDL type drug delivery agents in cancer chemotherapy. The use of both native and synthetic HDL as drug delivery agents is compared to evaluate their respective potentials for commercial and clinical development. The current status and future perspectives for HDL type nanoparticles are discussed, including current obstacles and future applications in therapeutics.

Objective We developed a modified Phalen's test (MPT), which uses sensory testing in Phalen's position, as a diagnostic screening tool for carpal tunnel syndrome (CTS). This study was designed to determine the sensitivity, specificity, and receiver operating characteristic (ROC) curve of the MPT for diagnosis of CTS. Methods Electrodiagnostic nerve conduction studies (EDS) were used as the gold standard. MPT was performed by a blinded examiner on patients prior to EDS. MPT was recorded as either positive or negative based on the presence or absence of a median nerve sensory deficit while the hand was in Phalen's position. Results Sixty-six hands were included in this study. Chi-square for the MPT compared to EDS as the gold standard was 41.449 (P < 0.001), and the validity coefficient (phi) was 0.792 (P < 0.01). The traditional Phalen's test (TPT) compared to the EDS demonstrated a chi-square of 15.349 (P < 0.001) and a phi coefficient of 0.482 (P < 0.01). ROC curve estimates for the MPT revealed a sensitivity of 84.4% compared to 50% for the TPT. The standard error of the estimate for sensitivity was 3.3% for the MPT and 5.8% for the TPT. Conclusion The MPT is a highly useful screening diagnostic tool for CTS. The MPT demonstrates greater accuracy than the TPT for predicting CTS. The MPT also demonstrates greater sensitivity than the TPT in predicting a positive electrodiagnostic test for CTS.

Cerebral blood flow velocity (CBFV) has been shown to significantly increase during dynamic exercise (running) secondary to increases in cardiac output. Static exercise (weight-lifting) induces supraphysiological arterial pressures up to 450/380 mmHg, and thus may alter CBFV. Catastrophic brain injuries such as stroke, cerebral hemorrhage, subarachnoid hemorrhage, retinal hemorrhage and retinal detachment have been associated with weight-lifting. A recent study has shown that intra-ocular pressure (IOP), which is an indirect measure of intracranial pressure, elevates to pathophysiologic levels during weight-lifting. Recent CBFV studies instituting Valsalva have demonstrated decreases in CBFV from 21%-52%. To date, no studies have examined CBFV during maximal weight-lifting to elucidate the cerebrovascular responses to extreme pressure alterations. We recruited nine elite power athletes, including a multi-world record holder in powerlifting, for a transcranial Doppler study of middle cerebral artery blood flow velocity at rest and during maximal weight-lifting. All subjects' resting blood flow velocities were within normal ranges (mean 64.4 +/- 9.5 cm sec2). Blood flow velocities were significantly (p < 0.0001) decreased in all subjects during maximal lifting (mean 48.4 +/- 10.1 cm sec2). Linear regression analysis demonstrated a significant inverse linear relationship in the net change of blood velocities from rest to maximal lift for each subject (r = 0.8585, p < 0.001). This study demonstrates that blood flow velocities are significantly decreased during heavy resistance training. The drop in CBFV during weight-lifting was significantly less than previous Valsalva studies, which likely reveals the cardiovascular, baroreflex, and cerebrovascular system adaptations occurring in these elite power athletes.

Apolipoprotein D (apoD) levels were examined in the temporal cortex as well as an assessment of the location of apoD positive cells within the brain by immunohistochemical and biochemical methods in young control (YC), aged control (AC), and Alzheimer's demented (AD) probands. Scattered apoD positive astrocytes and oligodendrocytes were found throughout the white matter by immunohistochemistry. ApoD immunoreactivity was also observed in the cerebellar oligodendrocytes of the YC group. There was faint positive apoD staining in scattered cortical astrocytes and a few neurons in the same group. In contrast, some of the AC and all of the AD probands had intense and frequent apoD immunostained cortical astrocytes and pyramidal neurons. The cortical senile plaques and neurofibrillary tangles were apoD immunonegative. No quantitative differences were found between the cortical apoD levels in the AC and AD groups, determined by immunoblotting. ApoD detected in the brain tissue was different in molecular weight (29 kDal) from that seen in CSF or in the serum (32 kDal). Our results indicate apoD is present in the human brain, especially in glial cells, and has increased abundance in the elderly and AD subjects.

Recent publications have suggested that intra-ocular pressure (IOP) may be an indirect assessment of intra-cranial pressure (ICP). Both IOP and ICP have similar physiologic pressure ranges and similar responses to changes in intra-abdominal, intra-thoracic and aortic pressure. Previous studies have demonstrated the relationships between retinal arterial pressure and aortic pressure, intra-ocular pressure and retinal venous pressure, intra-cranial pressure and retinal venous pressure. Power athletes routinely utilize the Valsalva maneuver during weightlifting. In fact there are reports of stroke, cerebral hemorrhage, subarachnoid hemorrhage, conjunctival, foveal and retinal hemorrhage, retinal detachment, hiatal hernia and pneumothorax associated with weightlifting. These events are thought to occur secondary to the extreme pressure elevations that occur in the intra-abdominal, intra-thoracic, intra-cranial, intra-ocular and vascular compartments. To date no human studies have examined the IOP changes that may occur with heavy resistance exercise. Therefore, we recruited power athletes (n = 11), who had participated in prior studies, from the local metropolitan area. The athletes had blood pressure status, drug screening and medical histories performed during previous investigations. Intra-ocular pressure was measured by noncontact tonometry at rest and during maximal isometric contraction. All subjects resting IOP were within normal ranges (mean 13 +/- 2.8 mmHg). Intra-ocular pressures were significantly (p < 0.0001) elevated in each subject during maximal contraction (mean 28 +/- 9.3 mmHg). One subject's IOP reached 46 mmHg during maximal contraction. Linear regression analysis demonstrated a significant linear relationship (r = 0.62, p < 0.0001) in the net change of IOP from rest to maximal contraction for each subject. This study demonstrates that IOP elevates to pathophysiologic levels during resistance exercise. The findings of conjunctival hemorrhages in two subjects further supports IOP being reflective of retinal venous pressure. The enormous pressures generated by power athletes during weightlifting leads to elevations in ICP which obstruct venous outflow leading to hemorrhage and elevations in IOP. The question remains as to whether these intermittent bursts of elevated IOP can lead to long-term pathological sequelae.

Several immunoassay models, including sandwich ELISA, solid phase ELISA and sink immunoassay and antibody combinations were investigated to develop an ELISA assay for LCAT with an appropriate linear range and sensitivity. Solid phase immunoassays were found to be most suitable for measuring LCAT from cell culture medium and in partially purified preparations. The immunoassays were analyzed for matrix interference, recovery studies, intra-run precision and inter-run precision. These studies have identified a reliable method for measuring LCAT in purified preparations and cell culture media, and provide the foundation for further development of immunoassays for clinical application.

Background That men have a higher risk of coronary heart disease has implicated testosterone as a risk factor. Lipoprotein levels have been reported to be altered by androgens, thus increasing the risk of coronary heart disease, myocardial infarction, and sudden death. The increasing abuse of anabolic steroids and reports of cases of sudden death and myocardial infarction among bodybuilders have raised concerns about an increase in cardiovascular risk for this population.Methods Twelve competitive bodybuilders were recruited for a comprehensive study on the cardiovascular risks associated with use of anabolic steroids. Six competitive heavyweight bodybuilders ingesting self-directed regimens of anabolic steroids (steroid group) and six competitive heavyweight drug-free bodybuilders were used for cardiovascular risk assessment. Apolipoproteins A-I and B, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, testosterone, and sex hormone-bind...

To investigate the relationship between resistance training, anabolic steroid use, and left ventricular function.Sixteen competitive bodybuilders were recruited for an echocardiography study.University of North Texas Health Science Center (Fort Worth, TX, U.S.A.); the cardiologist and technician were blinded as to subjects' drug status.Eight competitive heavyweight drug-free (DF) bodybuilders and eight competitive heavyweight body-builders on self-directed regimens of anabolic steroids.Average body mass indexes (BMI; kg/m2) for the drug-user (DU) and DF groups were not significantly different (34.1 +/- 2.8 and 32.0 +/- 4.3, respectively). Increases in left ventricular posterior wall and ventricular septal thickness were apparent in the DU group (p0.05). The ratio of echocardiographic findings to BMI revealed a significantly smaller left ventricular end-diastolic dimension (LVDEd/BMI; p0.05) in the DU group. The smaller LVDEd in DUs is coupled with a significantly disproportionate septal and posterior wall thickness in DUs when indexed to body mass compared to DFs. There was no direct evidence of diastolic dysfunction detected by mitral inflow velocity patterns.Anabolic steroids may potentiate concentric left ventricular hypertrophy with decreasing ventricular compliance without affecting cardiac function.

Early studies on ventriculoperitoneal shunt malfunctions demonstrated that proximal catheter obstruction was the most common cause for shunt malfunction and choroid plexus was the primary culprit for catheter obstruction. Subsequently, several studies were performed using stereotactic and endoscopic guidance systems to assist with optimal placement of proximal shunt catheters. Surgeons collectively agree that optimum placement of the proximal catheter tip is away from choroid plexus in the frontal horn. To achieve this catheter placement, neurosurgeons typically choose a frontal or parietal approach. Two previous studies comparing parietal and frontal shunt failure rates in the pediatric population have different conclusions. Thus, we decided to compare proximal catheter failure rates of frontal versus parietal approaches on 117 patients (ages ranging from 1 month to 80 years) who had undergone ventriculoperitoneal shunt placement at our institution. Statistical analysis demonstrated a significantly higher malfunction rate in the patients less than 3 years of age and a lower overall malfunction rate in patients shunted for normal pressure hydrocephalus. Surprisingly, there was no significant difference between the two surgical approaches. Thus, we concluded after reviewing the literature, that regardless of the initial surgical approach, the most important variable in shunt malfunction appears to be the final destination of the catheter tip in relation to the choroid plexus.

While the unique metabolic activities of malignant tissues as potential targets for cancer therapeutics has been the subject of several recent reviews, the role of cholesterol metabolism in this context is yet to be fully explored. Cholesterol is an essential component of mammalian cell membranes as well as a precursor of bile acids and steroid hormones. The hypothesis that cancer cells need excess cholesterol and intermediates of the cholesterol biosynthesis pathway to maintain a high level of proliferation is well accepted, however the mechanisms by which malignant cells and tissues reprogram cholesterol synthesis, uptake and efflux are yet to be fully elucidated as potential therapeutic targets. High and low density plasma lipoproteins, area the likely major suppliers of cholesterol to cancer cells and tumors, potentially via receptor mediated mechanisms. This review is primarily focused on the role(s) of lipoproteins in carcinogenesis, and their future roles as drug delivery vehicles for targeted cancer chemotherapy.

Purpose : Biweekly (once every 2 weeks) heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) therapy was evaluated for safety and efficacy in selectively reducing LDL cholesterol levels compared with weekly HELP therapy. Patients and methods : Biweekly treatments were given to high-risk, diet/drug resistant hypercholesterolemic patients ( n = 23) after 6 months of weekly HELP therapy. Lipids, lipoprotein cholesterol, apolipoproteins A-I and B, and fibrinogen were measured on plasma samples before and after treatment. Results : Mean plasma volume treated was 2.8 l and mean treatment duration 1.7 h. Therapy complications were minimal. In 98% of 268 biweekly HELP treatments, LDL cholesterol levels were reduced by >30%. For patients completing 6 months of biweekly therapy following 6 months' weekly therapy ( n = 23), mean LDL cholesterol levels were reduced 138.5 mg/dl (111.2 mg/dl weekly) with a time-averaged decrease from mean pre-apheresis levels of 33% for biweekly therapy (39% weekly). Mean total cholesterol (161.2 mg/dl biweekly versus 132.9 weekly) and apolipoprotein B (104.6 mg/dl versus 92.6) levels were also reduced with each treatment. Mean HDL cholesterol was reduced only 6.1 mg/dl (6.3 mg/dl weekly). Conclusions : Biweekly HELP treatments can safely reduce LDL cholesterol levels as consistently as weekly HELP treatments. However, the higher pre-treatment LDL cholesterol levels with biweekly treatments may produce less therapeutic benefit than with weekly therapy.

Expression of the lipophilic ligand transporter, apolipoprotein D (apoD) by primary astrocyte cultures derived from neonatal mouse brain was investigated. Western blot analysis of cell lysates and media showed that apoD is constitutively secreted by astrocytes with little intracellular storage. The secreted apoD floated primarily at density 1.063-1.21 g ml -1 upon sequential ultracentrifugation indicating its association with lipids. Treatment of astrocytes with the carboxylic ionophore, monensin, resulted in intracellular retention and decreased secretion of apoD that was of slightly reduced M r . Progesterone, a steroid hormone that binds to apoD with high affinity (10 -6 mol l -1 ) and the oxysterol, 25-hydroxycholesterol which is a potent regulator of cellular cholesterol homeostasis in mammalian cells, differentially stimulated apoD, but not apoE secretion. These results show that astrocytes synthesize and constitutively secrete apoD and suggest a physiologic role for this lipocalin in cholesterol metabolism in the nervous system

An 8-year-old developmentally normal boy (status: post third ventriculostomy and resection of posterior fossa low-grade glioma 4 years earlier and with known history of ventriculomegaly/arrested hydrocephalus) presented to the emergency room with vomiting and lethargy after a minor head trauma. Computed tomography scan of the head revealed no acute changes since previous studies. However, the patient's neurological status rapidly declined in the emergency room, where an emergency ventriculostomy demonstrated increased intracranial pressure. The patient's clinical condition improved over 24 h: he underwent placement of a ventriculoperitoneal shunt without complications and was discharged intact.The pathogenesis of rapid neurological decline associated with minor head trauma in chronic hydrocephalus is reviewed.

Eight patients and eight age matched controls were recruited to study parameters related to plasma lipoprotein metabolism in Alzheimer's disease based on previous studies in Down's syndrome (A.G. Lacko et al., Clin. Chim. Acta, 132 (1983) 133). The fractional rate of cholesterol esterification (% cholesterol esterifed per hour) was 16% lower in the patient group compared with controls. Correlational analyses of lecithin/cholesterol acyltransferase (LCAT) activity and plasma lipids revealed additional differences between the Alzheimer's patients and control subjects. These data are strikingly similar to those obtained earlier with Down's syndrome patients. These data, combined with analyses of cholesteryl ester transfer protein (CETP) levels, suggest that reverse cholesterol transport in general and CETP activity in particular may be altered in Alzheimer's disease.

In this study we used monoacid triacylglycerols of various acyl-chain lengths as substrates for probing the active-site structure and substrate specificity of lipoprotein lipase (LPL). An unexpected finding was that the albumin ligand binding site is accessible not only to long-chain fatty acids for its recognized functional role as a fatty acid acceptor, but also to short- and medium-chain monoacid triacylglycerol substrates. The observed striking inhibitory effect (99%) of albumin on the LPL-catalyzed hydrolysis of trihexanoylglycerol is probably the result of the high affinity interaction of albumin with this substrate. Spectrophotometric analyses indicated that there is one high affinity binding site per albumin molecule (apparent KD = 1.8 +/- 0.9 microM) for the interaction with trihexanoylglycerol. Despite LPL acyl-chain specificity being obscured by the substrate binding effect of albumin, a systematic study of the lipolysis reaction under various assay conditions demonstrated that tributyroylglycerol represents the best substrate for LPL, and the preferential order of LPL catalysis for both the basal and apoC-II-activated activities is: C4 > C6 > C8 > C10 > C12 > C18:1. In some assay conditions, the presence of albumin affects the above-mentioned order, which can be attributed to substrate binding by albumin, rather than an alteration in the specificity of LPL. The synergistic effect of apoC-II and albumin resulted in the preferential activation of LPL for the hydrolysis of long-chain triacylglycerols. Even with optimal assay conditions for the hydrolysis of long chain triacylglycerols, there is still a preferential reactivity of LPL with short- and medium-chain triacylglycerols.

The effects of treatment, on plasma lipids in patients with Type II hypercholesterolemia, for 8–24 weeks was determined with pravastatin (PR) and cholestyramine (CH) given alone or in combination. The first 8 weeks of treatment included a parallel placebo (P) control, while the subsequent period to 24 weeks compared four groups (40 and 80 mg PR, CH, and PR + CH). There were seven to nine patients per group (average age of 58 years). Cholesterol (C) and low-density lipoprotein cholesterol (LDL-C) decreased with PR and CH. There were inconsistent and nonsignificant effects on triglycerides and high-density lipoprotein cholesterol (HDL-C). Apolipoproteins A-I, A-II, B, and Lp(a) were measured, and only Apo-B decreased with drug therapy. Lipoprotein particles characterized by their specific apolipoprotein content were also measured. LpB Cholesterol ester-rich, containing predominantly Apo-B, decreased with PR and CH relative to their respective baselines, but not relative to P. Similarly, triglyceride-rich, LpBc, a complex lipoprotein particle containing apolipoproteins A-I, A-II, B, C, D, and E decreased relative to baseline, but not with respect to P. This study has further defined the effect of PR and CH on lipids and lipoprotein particles in patients with Type II hypercholesterolemia. These effects might be favorable in relation to reduction of risk factors in atherosclerosis. © 1992 Wiley-Liss, Inc.

Recombinant DNA-derived apolipoprotein(a) was used to demonstrate that the apo(a) moiety of lipoprotein(a) (Lp(a)) is responsible for the binding of Lp(a) to other apolipoprotein B-containing lipoproteins (apoB-Lp) including LDL2, a subclass of low density lipoproteins (d = 1.030-1.063 g/ml). The r-apo(a).LDL2 complexes exhibited the same binding constant as Lp(a).LDL2 (10(-8) M). Treatment of either recombinant apo(a) or Lp(a) with a reducing agent destroyed binding activity. A synthetic polypeptide corresponding to a portion of apo(a)'s kringle-4 inhibited the binding (K1 = 1.9 x 10(-4) M) of LDL2 to Lp(a). Therefore, we concluded that binding to apoB-Lp was mediated by the kringle-4-like domains on apo(a). Using ligand chromatography which can detect complexes having a KD as low as 10(-2) M, we demonstrated the binding of plasminogen to apoB-Lp. Like Lp(a), binding of plasminogen to apoB-Lp was mediated by the kringle domain(s). The differences in binding affinity may be due to amino acid substitutions in the kringle-4-like domain. In most of the kringle-4-like domains of apo(a), the aspartic residue critical for binding to lysine was substituted by valine. Consistent with this substitution, we found that L-proline and hydroxyproline, but not L-lysine, inhibited the binding of LDL2 to apo(a). Inhibition by L-proline could be reversed in the binding studies by increasing the amount of apo(a); and L-proline-Sepharose bound plasma Lp(a), suggesting that L-proline acted as a ligand for the kringle-4-like domain(s) of apo(a) involved in the binding of apoB-Lp. The binding of apo(a) to proline and hydroxyproline could be responsible for the binding of apo(a) to the subendothelial extracellular matrix, i.e. domains of proteins rich in proline or hydroxyproline (e.g. collagen and elastin).

This review evaluates drug delivery systems that involve intact plasma lipoproteins or some of their components. These complex macromolecules transport highly water-insoluble compounds (cholesteryl esters and triacylglycerols) in their natural environment - a property that renders them ideal carriers of hydrophobic drugs. Particular emphasis is placed on the application of lipoproteins as drug delivery agents in cancer chemotherapy. The history and present activity regarding lipoprotein-based formulations are reviewed, with the primary focus on the smaller sized (low and high density) lipoprotein-based formulations and their potential clinical and commercial value. The use of both native and synthetic lipoproteins as drug delivery agents are discussed from the standpoint of therapeutic efficacy, as well as commercial feasibility. The advantages of lipoprotein-based drug delivery formulations are compared with other drug delivery models, with the primary focus on liposomal preparations. Finally, an expert opinion is provided, regarding the potential use of lipoprotein-based formulations in cancer treatment, taking into consideration the major advantages (biocompatibility, safety, drug solubility) and the barriers (manufacturing protein components, financial interest, investments) to their commercial development.

Coronary artery bypass graft (CABG) surgery is a common procedure for patients with coronary artery disease. The physiologic effects of postoperative osteopathic manipulative treatment (OMT) following CABG have not been documented previously.To determine the effects of OMT on cardiac hemodynamics post-CABG surgery.Pilot prospective clinical study (N=29).Treatment subjects (n=10) undergoing CABG surgery were recruited for postoperative OMT. The primary assessment compared, pre-OMT versus post-OMT, measurements of thoracic impedance, mixed venous oxygen saturation (SvO2), and cardiac index. Records of control subjects (n=19) who underwent CABG surgery--but who did not receive OMT--were assessed for SvO2 and cardiac index at 1 hour and 2 hours postsurgery.Immediately following CABG surgery (or = 2 h), OMT was provided to subjects to alleviate anatomic dysfunction of the rib cage caused by median sternotomy and to improve respiratory function. This adjunctive treatment occurred while subjects were completely anesthetized.A post-OMT increase in thoracic impedance (Por = .02) in OMT subjects demonstrated that central blood volume was reduced after OMT, suggesting an improved peripheral circulation. Mixed venous oxygen saturation also increased (Por = .005) after OMT. These increases were accompanied by an improvement in cardiac index (Por = .01). Comparisons of postoperative measurements in OMT subjects versus those in control subjects revealed statistically significant differences for SvO2 (Por = .005) and cardiac index (Por = .02) between the two groups.The observed changes in cardiac function and perfusion indicated that OMT had a beneficial effect on the recovery of patients after CABG surgery. The authors conclude that OMT has immediate, beneficial hemodynamic effects after CABG surgery when administered while the patient is sedated and pharmacologically paralyzed.

The Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) first reported its results in 1998, before the 2001 publication of the National Cholesterol Education Program-Adult Treatment Panel III guidelines (NCEP-ATP III) and 2004 update. Our objective was to investigate the impact of these guidelines on the AFCAPS/TexCAPS cohort. The main outcome measures were the event rates of first acute major coronary events (AMCEs), which were reduced 39% by lovastatin (95% confidence interval [CI] 21% to 53%, p

Because of their physicochemical properties and the selective receptor-mediated uptake of their core components, reconstituted high-density lipoproteins have unique advantages over conventional formulations to serve as targeted drug delivery agents.

To date, there are no broad-based studies defining the standard of care for pediatric neurosurgeons in the area of cranial fixation. Thus, the techniques for cranial fixation remain largely surgeon dependent. Over the past few years, there have been several new cranial fixation devices approved for use in the United States. To gain insights into techniques currently in use by pediatric neurosurgeons, we polled all pediatric neurosurgeons listed in either the American Society of Pediatric Neurosurgeons or the International Society of Pediatric Neurosurgeons regarding their techniques for cranial fixation in a variety of age groups. These survey findings may provide a basis for establishing recommendations and lead to a standard of care for cranial fixation techniques among pediatric neurosurgeons.

Recombinant high density lipoprotein (rHDL) particles were prepared with defined composition (phosphatidylcholine, apolipoprotein A-1, cholesterol and cholesteryl esters) and a molecular weight of approximately 187,000 kdaltons. Three molecules of taxol per rHDL particle were incorporated into these rHDL complexes.Cholesteryl ester and taxol (HDL core components,) were taken up efficiently by several cancer cell lines compared to transformed normal ovarian cells (HGL5) used as the control. Immunoblotting with the scavenger receptor (SR-B1) antibody revealed strong immunoreactivity of several cancer cell lines.Our studies indicated that rHDL complexes can be used as efficient drug delivery vehicles due to the ability of cancer cells to acquire HDL core components. Targeting of anticancer drugs as components of the rHDL complex could result in reduction of toxic side-effects during chemotherapy.

In the enrollment phase of the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS), a number of heart disease-free potential subjects did not qualify to participate in the study because their low-density lipoprotein cholesterol (LDL-C) levels fluctuated. This report looks at the incidence of lability of LDL-C levels and premature coronary heart disease (CHD) in the nuclear family based on data collected on a group excluded primarily based on lipid levels during the enrollment phase at the TexCAPS site. Lipid inclusion criteria were total cholesterol (TC), 180 mg/dL to 264 mg/dL; low-density lipoprotein cholesterol (LDL-C), 130 mg/dL to 190 mg/dL; high-density lipoprotein cholesterol (HDL-C), less than or equal to 45 mg/dL for men and less than or equal to 47 mg/dL for women; and triglyceride (TG) concentrations, less than or equal to 400 mg/dL. After participants had been on the American Heart Association (AHA) step 1 diet for 8 to 10 weeks, lipid parameters were again tested in a total of 4257 individuals. Both lipid screening measurements at 8 and 10 weeks were required to be within 15% of each other for inclusion in subsequent study. A total of 2868 individuals met the study criteria and were randomly assigned to groups; 1389 failed to qualify for a variety of reasons. Of these, 1070 (25.1% of those who initially qualified based on lipid levels) were excluded because of unacceptable lipid levels on the evaluations repeated at 8 and 10 weeks. This excluded subpopulation (n = 1070) was stratified into three groups based on changes of LDL-C between 8 and 10 weeks on the AHA step 1 diet. One group had a less than 15% fluctuation in LDL-C (LN group, n = 637, 15.0% of cohort, n = 4257). Of those with LDL-C variability, 177 had a greater than 15% increase in LDL-C (LI group, n = 177, 4.2% of cohort); and 256 had a greater than 15% decrease in LDL-C (LD, n = 256, 6.0% of cohort). At week 8, TC and LDL-C levels were lower and the HDL-C level was higher in the LN group compared with both groups having labile lipid levels (LI and LD groups). Changes by gender showed similar trends; however, HDL-C was 5 mg/dL lower at 8 weeks in both groups of women with labile LDL-C levels (groups LI and LD) when compared with the women in the LN group (P.01). The frequency of TG concentrations greater than 150 mg/dL was greater in men having labile LDL-C level when compared with the control group. The trend was similar for women. In assessing the incidence of CHD in the nuclear family, parents of probands with labile LDL-C levels (LI and LD groups) had a higher frequency (P = .0044) of premature CHD than parents of probands with stable LDL-C (LN). The following conclusions can be drawn: (1) within the general population, there is a substantial number (10%, 433 of 4257) of individuals with labile LDL-C levels; (2) labile LDL-C levels in the probands were found to be associated with an increased familial frequency of premature CHD in their parents. Definition of the molecular basis for this lability of LDL-C could reveal new opportunities to regulate plasma cholesterol levels and thus have an impact on CHD-associated morbidity and mortality in a substantial portion of the general population.

This is a first report of aortic valve thickening secondary to intermittent hypertensive episodes experienced with weight lifting.

Lipoprotein (a) [Lp(a)], a risk factor for coronary artery disease, is a LDL-like particle with apolipoprotein (a) [apo(a)] covalently linked to apolipoprotein B (apoB). Apo(a) has many repeats of kringle 4-like domain, classified as type 1 through type 10 (T1–T10). Deletion analysis was performed to define the functional modules of human apo(a). We found that T7 has an affinity for cell surfaces and is required for Lp(a) formation. Cell surface binding was inhibited by l -proline, K I = 4.7 ± 3.6 mM (n=3). We also found that T8 has an affinity for subendothelial extracellular matrix (ECM). ECM binding was inhibited modestly by l -proline (K I = 6.1 ± 1.9 mM, n=3), and more effectively by l -lysine (K I = 2.7 ± 1.0 mM, n=3) and its analogue, 6-aminohexanoic acid (K I = 0.35 ± 0.13 mM, n=3). These data point to T7 and T8 as important functional modules of apo(a).

Lipoprotein(a) (Lp(a)), a risk factor for coronary artery disease, is a LDL-like particle with apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B (apoB), the main protein component of LDL. Apo(a) is highly homologous to plasminogen and its gene probably arose by duplication of the plasminogen gene. It has many repeats of kringle-4-like domain, classified as type 1 through type 10 (T1-T10). T9 is responsible for the covalent linkage between apo(a) and LDL. However, we found that T9 has no affinity for LDL. Therefore, an initial noncovalent interaction between apo(a) and LDL is necessary to bring T9 and LDL together. T6 and possibly T7 of apo(a) were identified as the kringles which mediate this initial interaction. With these findings, a two-step model for Lp(a) formation is proposed. This model should be useful in the design of Lp(a) formation inhibitors. These inhibitors are potential anti-hyperlipoprotein(a) drugs.

Background: Human mammary tissue metabolizes lipids from plasma, a process affected by female gonadal hormones. Both benign and malignant proliferation of breast tissue in women have been associated with changes in plasma lipid and lipoprotein levels.Methods: One hundred consecutive women with breast masses (50 malignant, 50 benign) had diagnostic biopsies followed by axillary node dissection in those with cancer. Fasting serum samples were taken just prior to biopsy and analyzed for lipid fatty acid and lipoprotein levels. Malignant breast tissue was analyzed for hormone receptor binding.Results: Low-density lipoprotein (LDL) components (total cholesterol, LDL-cholesterol, apolipoprotein B) were increased, but not significantly, in cancer patients compared to those with benign masses. Decreased levels of LDL-associated components were found in women with cancer recurrence by 3 years. Three apolipoproteins of high-density lipoprotein (apolipoprotein A-I, apolipoprotein A-II, apolipoprotein D) were more affected by the presence of breast masses than the lipids were. Fibrocystic disease, type of hormone binding, and recurrence within 3 years were significantly related to apolipoprotein changes, especially apolipoprotein D levels with hormone receptor binding and the apolipoprotein A-I/apolipoprotein B ratio with breast cancer recurrence.Conclusions: Prior to diagnostic biopsy, serum lipid and apolipoprotein components of low-density lipoproteins were increased in women with fibrocystic disease and early stage cancer but decreased in women with early recurrence. However, apolipoprotein A-I, apolipoprotein A-II, and apolipoprotein D, of the high-density lipoproteins, were more affected than serum lipids. The ratio of apolipoprotein A-I to apolipoprotein B serum levels at time of biopsy was the best predictor of cancer recurrence.

We found a significantly reduced incidence of increased lipoprotein(a) (Lp(a)) levels in subjects with triglycerides (TG) greater than 150 mg/dl compared with those with TG levels lower than 150 mg/dl. This was the case in patients with angiographically documented coronary artery disease (CAD) and in subjects with no CAD. We explored the potential role of lipoprotein lipase (LPL) in mediating this relationship. Lp(a) and LDL2 exhibited a minimal effect on the rate constant for degradation of VLDL-TG by LPL (13% inhibition). Binding analyses indicated no differences between VLDL and LDL with respect to Lp(a) binding, and lipolysis only reduced binding by 30% at 75% degradation of VLDL-TG. Our study indicates that the inverse relationship between elevated plasma TG and Lp(a) levels is not caused by activation of LPL by Lp(a) either due to failure of Lp(a) to bind to VLDL or its lipolytic remnants. It is hypothesized that this relationship could stem from the enhanced clearance of TG-rich lipoproteins in individuals with higher levels of Lp(a) by receptor-mediated events.

RNA interference holds tremendous potential as a therapeutic approach, especially in the treatment of malignant tumors. However, efficient and biocompatible delivery methods are needed for systemic delivery of small interfering RNA (siRNA). To maintain a high level of growth, tumor cells scavenge high-density lipoprotein (HDL) particles by overexpressing its receptor: scavenger receptor type B1 (SR-B1). In this study, we exploited this cellular characteristic to achieve efficient siRNA delivery and established a novel formulation of siRNA by incorporating it into reconstituted HDL (rHDL) nanoparticles. Here, we demonstrate that rHDL nanoparticles facilitate highly efficient systemic delivery of siRNA in vivo, mediated by the SR-B1. Moreover, in therapeutic proof-of-concept studies, these nanoparticles were effective in silencing the expression of two proteins that are key to cancer growth and metastasis (signal transducer and activator of transcription 3 and focal adhesion kinase) in orthotopic mouse models of ovarian and colorectal cancer. These data indicate that an rHDL nanoparticle is a novel and highly efficient siRNA carrier, and therefore, this novel technology could serve as the foundation for new cancer therapeutic approaches.

Heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) weekly therapy was evaluated for safety and efficacy in selectively reducing LDL cholesterol levels. Weekly treatments (25) were given to high-risk hypercholesterolemic patients (n = 33) with screening LDL cholesterol levels > 160 mg/dl despite prior diet and drug therapy. Lipids, lipoprotein cholesterol, apolipoproteins A-l and B, and fibrinogen were measured on plasma samples before and after treatment. Mean plasma volume treated was 2.66 liters and mean treatment duration 1.7 hours. Therapy complications were infrequent and were primarily vascular access problems or hypotension. Treatment goals were > 30% LDL cholesterol reduction with each treatment. In 98% of 686 HELP treatments, LDL cholesterol levels were reduced > or = 30%. Mean LDL cholesterol levels were reduced 111.0 mg/dl (54%) with a time-averaged decrease of 39% over a 25-week course. Mean HDL cholesterol was reduced only 6.2 mg/dl (15%). Total cholesterol (134.4 mg/dl; 47% decrease) and apolipoprotein B (88.7 mg/dl; 53% decrease) levels were also reduced. Fibrinogen decreased 158.2 mg/dl (58%) without bleeding complications. HELP therapy can safely and selectively remove plasma LDL cholesterol, producing consistent reductions in LDL cholesterol, total cholesterol and apolipoprotein B levels.

The fatty acid composition of plasma triglycerides, phospholipids, and cholesterol esters have been studied during gemfibrozil (G)-induced lipid-lowering treatment in six patients with hypertriglyceridemia. Gemfibrozil caused significant plasma triglyceride reductions from 776 +/- 573 to 226 +/- 82 mg/dL (P < .001). Gemfibrozil therapy also caused significant changes in the plasma lipid fatty acid composition, mainly by increasing palmitoleic acid (16:1) in triglycerides (2.1-5.6%) and cholesterol esters (2.2-3.7%), concomitant with the significant decrease in the content of the linoleic acid (18:2) in phospholipids (20.1-16.0%) and triglycerides (18.0-15.2%). The ratio of unsaturated fatty acids (20:3 + 20:4/18:2) was increased in the phospholipid fraction. These findings support a G effect on the desaturation of fatty acids in patients with hypertriglyceridemia. Because fatty acid composition was significantly altered by G, those biologic systems dependent on the pattern of fatty acids may be modified in clinical important ways.

A method combining ligand dot blotting and digital imaging was used to determine the apparent dissociation constant (KD) for the binding of lipoprotein(a) to low-density lipoproteins (Lp(a)-LDL2). By use of this approach, the KD for the Lp(a)-LDL2 complex was shown to be in the nanomolar range [(1.05 +/- 0.21) x 10(-8) M, n = 4]. The Lp(a)-LDL2 interaction was both hydrophobic and ionic; however, hydrophobic forces predominated because the interaction was demonstrable at high salt concentration (greater than 2 M NaCl), while no complex was detectable at low salt concentration (less than 0.08 M NaCl). Consistent with the hydrophobic nature of this interaction, the Lp(a)-LDL2 complex was stable over a wide pH range (4-10). Plasminogen did not compete with Lp(a) binding to LDL2 even at a 2.2 X 10(3) molar excess of plasminogen over the LDL2 concentration. The only component identified in plasma and serum that inhibited the binding of LDL2 to Lp(a) was apolipoprotein B containing lipoproteins (apoB-Lp). These studies indicate that the Lp(a)-LDL2 complex could exist in plasma. In fact, up to 72% of purified Lp(a) added to an Lp(a)-negative hypertriglyceridemic plasma floated with apoB-Lp (d less than 1.063 g/mL) following ultracentrifugation, whereas only 9% of the purified Lp(a) added to the apoB-Lp-free 1.12 g/mL infranate floated at d less than 1.063 g/mL. The formation of a complex of Lp(a) with apoB-Lp could increase the amount of cholesterol ester bound per cellular receptor, e.g., LDL receptor, and thus potentially accelerate cholesterol removal from the vascular compartment.

Lp(a) lipoprotein purified from human plasma bound with high affinity to isolated bovine LDL receptors on nitrocellulose blots and in a solid-phase assay. Lp(a) also competed with 125I-LDL for binding to human LDL receptors in intact fibroblasts. Binding led to cellular uptake of Lp(a) with subsequent stimulation of cholesterol esterification. After intravenous injection, human Lp(a) was cleared slowly from the plasma of normal mice. The clearance was markedly accelerated in transgenic mice that expressed large amounts of LDL receptors. We conclude that the covalent attachment of apo(a) to apo B-100 in Lp(a) does not interfere markedly with the ability of apo B-100 to bind to the LDL receptor and that this receptor has the potential to play a major role in clearance of Lp(a) from the circulation of intact humans.

Anabolic steroid use is widespread and has been associated with a variety of pathological conditions. The subject of this case is a 20-year-old amateur bodybuilder who died of sudden cardiopulmonary arrest. He had no previous medical complaints but had a history of anabolic steroid abuse and a hypertrophic heart (515 g) at autopsy. This case presentation will discuss the cardiovascular effects of these drugs and the possible impact of long-term abuse.