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Biomedical subjects

W Gross

Publications and source records attributed to W Gross.

At least 55 records · Page 3Linked to original sources
PubMed1996

Apolipoprotein E polymorphism is associated with both senile plaque load and Alzheimer-type neurofibrillary tangle formation.

Recent work provided evidence that the apolipoprotein (apo) E polymorphism is associated with late-onset sporadic Alzheimer's disease. The major histological hallmarks of Alzheimer's disease are the extraneuronal deposition of A4/beta-amyloid and the intraneuronal formation of neurofibrillary tangles, the latter correlating strongly with the psychometric status. We examined the relationship between the apo E polymorphism and Alzheimer's disease-related histological changes using a staging system which accounts for the progression of the disease over time and correlates well with the cognitive decline ante mortem. We observed a significant positive correlation between both neurofibrillary changes and A4/beta-amyloid deposits and the epsilon 4 gene dose. We estimated that the presence of one apo E4 allele leads to an earlier onset of the histopathological process of about one decade. The association of both types of Alzheimer's disease-related changes with the prevalence of the epsilon 4-allele suggests that the apo E polymorphism causally contributes to the development of Alzheimer's disease.

Aging↗
PubMed1996

Semantide- and chemotaxonomy-based analyses of some problematic phenotypic clusters of slowly growing mycobacteria, a cooperative study of the International Working Group on Mycobacterial Taxonomy.

During previous cooperative numerical taxonomic studies of slowly growing mycobacteria, the International Working Group on Mycobacterial Taxonomy described a number of strains whose taxonomic status was ambiguous. A new study of DNA, RNA, and proteins from 66 of these organisms was performed to correlate their properties with phenotypic clustering behavior; the results of this study permitted 51 of the strains studied to be assigned to known species. The methods used to characterize the semantides included nucleotide sequencing and assessment of levels of semantide relatedness by affinity binding techniques, including whole DNA-DNA hybridization, probe hybridization, and antibody binding. There was good overall agreement between the phenotypic and chemotaxonomic clusters and the groups of organisms identified by semantide analyses. Our results supported the conclusion that we should continue to rely on polyphasic taxonomy to provide satisfactory systematic resolution of members of the genus Mycobacterium. We identified no single 16S rRNA interstrain nucleotide sequence difference value that unequivocally defined species boundaries. DNA-DNA hybridization remains the gold standard, but common resources are needed to permit DNA-DNA hybridization analyses to be made available to laboratories that are not prepared to use this technology. One of the large novel clusters which we studied corresponds to the recently described species Mycobacterium interjectum, a pathogen that resembles the nonpathogen Mycobacterium gordonae phenotypically. We also identified strains that appear to represent ribovars of Mycobacterium intracellulare which do not react with the commercial diagnostic probes that are currently used for identification of this species. Other branches or clusters consisted of too few strains to permit a decision about their taxonomic status to be made.

Bacterial Proteins↗
PubMed1996

Low-density lipoprotein susceptibility to in vitro oxidation in healthy smokers and nonsmokers.

We analyzed the susceptibility of low-density lipoproteins (LDL) to oxidation in 17 healthy smokers (43.3 +/- 16.8 pack-years) and 19 healthy nonsmokers, matched for age (smokers: 52 +/- 7 years; nonsmokers: 53 +/- 7 years), gender, and relative body mass. Cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and apolipoprotein (apo) B were not different between smokers and nonsmokers; apo A-I was slightly lower in smokers (one-tailed P = 0.066). To study whether LDL from smokers were prone to in vitro oxidation than LDL from nonsmokers, we measured the time kinetics of diene formation and the production of malondialdehyde during oxidation of LDL in vitro. In smokers and nonsmokers, respectively, the mean (+/-SD) lag times (tinh) of diene formation were 111 +/- 26 and 100 +/- 27 min, the peak rates of diene formation (Vmax) were 5.99 +/- 2.34 and 6.34 +/- 2.30 mmol x min-1 x g-1, and the amounts of dienes produced during the propagation phase (dmax) were 250 +/- 264 and 248 +/- 56 mmol x g-1. Neither the malondialdehyde content of LDL (measured as thiobarbituric acid-reactive substances) before oxidation nor the amount of malondialdehyde generated during oxidation (smokers: 57.0 +/- 14.2 micromol x g-1; nonsmokers: 63.2 +/- 15.2 micromol x g-1 indicated any statistically significant effect of smoking. When nonsmokers and smokers were considered together, the amount of malondialdehyde generated during oxidation correlated with age (nonparametric rs = 0.405), body mass index (r2 = 0.573), and concentrations of apo B (rs = 0.480), cholesterol (rs = 0.448), triglycerides (rs = 0.436), and LDL cholesterol (rs = 0.398). Our data show that smoking is not associated with increased oxidizability of LDL in healthy men and women at ages 42-63 years.

Adult↗
PubMed1995

Purification and characterization of a galactose-1-phosphate: UDP-glucose uridyltransferase from the red alga Galdieria sulphuraria.

The galactose-1-phosphate uridyltransferase of the red alga Galdieria sulphuraria has been purified about 1800-fold to a final specific activity of approximately 140 U/mg protein. The purification involved chromatography on DEAE-Fractogel, hydroxyapatite, decyl-agarose, and DEAE-Tentacle gel. After SDS/PAGE, the enzyme preparation showed only one protein band of 42 kDa. The enzyme is a homodimer with a molecular mass of 82 kDa as estimated from the sedimentation velocity or 60 kDa as estimated by gel filtration. It has a broad pH optimum between pH 7 and pH 9. The apparent Km values for the forward and backward reactions are Km(Glc1P) = 105 microM, Km(UDP-galactose) = 30 microM, Km(Gal1P) = 400 microM, and Km(UDP-Glc) = 20 microM. The activation energy of the reaction is 45 kJ mol-1. The enzyme is specific for the galactose 1-phosphate to UDP-galactose interconversion in the Leloir pathway while the alternate enzyme for the Isselbacher pathway, UDP-galactose pyrophosphorylase, could not be detected in G. sulphuraria.

Chromatography, Gel↗
PubMed1995

Apolipoprotein E polymorphism influences not only cerebral senile plaque load but also Alzheimer-type neurofibrillary tangle formation.

Only recently, evidence was provided that apolipoprotein E allele epsilon 4 located on Chromosome 19 is associated with late onset (i.e. senile) sporadic Alzheimer's disease. Histologically, Alzheimer's disease is associated with intraneuronal neurofibrillary changes and extraneuronal A4/beta-amyloid deposition. We set out with a histological staging system which considers the gradual development of Alzheimer's disease-related histological changes over time and correlates highly with the cognitive decline ante mortem. Our analysis revealed that both the mean stage for A4/beta-amyloid deposits and the mean stage for neurofibrillary tangles get significantly shifted upwards in epsilon 4-carriers. This represents an earlier onset of the histopathological process of about one decade. The fact that both types of Alzheimer's disease-related changes correlate positively with the prevalence of the epsilon 4-allele suggests for a causal relationship between the apolipoprotein E polymorphism and the development of Alzheimer's disease.

Age Factors↗
PubMed1995

Common genetic variants of lipoprotein lipase that relate to lipid transport in patients with premature coronary artery disease.

Two common coding sequence mutations of lipoprotein lipase (serine447-ter, producing a carboxy terminal truncation; and asp9-asn variants) were studied in 329 Caucasian subjects, of whom 243 had angiographic features of premature atheroscelerosis (220 with coronary artery disease; 23 with coronary and peripheral artery disease). As expected, the mean levels of cholesterol, triglycerides, LDL-cholesterol, ApoB and Lp(a) were significantly higher in the arterial disease group than in the controls. HDL levels were lower in the patient group. With regard to the common mutations, plasma triglycerides and VLDL-triglycerides were lower in subjects possessing the Serine447-Ter mutation (p = 0.06 and < 0.05, respectively). When the lipid distributions were analysed by tertiles, the Ser447-Ter mutation was significantly less frequent in the highest tertiles for triglycerides (p < 0.02), and VLDL (p < 0.04). The Asp9-Asn substitution was significantly more frequent in the lowest tertiles for ApoAI (p = 0.05). Case-control analyses of genotypic distributions between the two groups with or without arterial disease did not show any significant differences. The possible functional effects of these common mutants of lipoprotein lipase are discussed.

Asparagine↗
PubMed1995

Short- and long-term effects on lipid metabolism of oral contraceptives containing 30 micrograms ethinylestradiol and 150 micrograms desogestrel or 3-keto-desogestrel.

During a cross-over study with young female volunteers, the effects of a combination of 30 micrograms ethinylestradiol (EE) and 150 micrograms desogestrel (DG) or 3-keto-desogestrel (KDG) upon lipid metabolism were investigated on day 3 of the first cycle (day 3/I) and on day 21 of the third cycle of treatment (day 21/III). As compared to the control cycle, total cholesterol (CH), low-density lipoprotein CH (LDL-CH), and the apolipoproteins A-II and B were reduced already on day 3/I, the effects being more pronounced with the DG-containing formulation. On day 21/III of treatment with EE/DG, the levels of total CH, LDL-CH and apolipoprotein B did not differ from controls, while apolipoprotein A-II was significantly increased. The effects of EE/KDG were similar, except that on LDL-CH which was still reduced on day 21/III. The serum concentrations of total triglycerides (TG), very low-density lipoprotein CH (VLDL-CH), VLDL-TG, LD-TG, high-density lipoprotein CH (HDL-CH), HDL-TG, and apolipoprotein A-I were not significantly affected on day 3/I, but elevated on day 21/III. As during treatment with EE/KDG the peak level of KDG was higher than with EE/DG, the results indicate a more pronounced antagonistic effect of EE/KDG on some EE-induced changes on lipoproteins during the first days of intake. These short-term changes possibly reflect a rapid enhancement of hepatic uptake of remnants and LDL by EE. During long-term treatment, the other effects of EE, e.g. the stimulation of hepatic synthesis of TG, VLDL, and HDL and the inhibition of hepatic lipoprotein lipase, become apparent.

Adult↗
PubMed1995

[Gorham-Stout massive ostelysis. A case report].

One case of massive osteolysis Gorham-Stout is presented. Idiopathic osteolysis is a rare disease. The coincidental radiological diagnosis following minor trauma or a few months' history of mild pain involving joints is characteristic. The disease process has a sudden onset. Bones undergo partial or complete resorption, which may spread across joints to contiguous bones. The osteolytic process eventually ceases spontaneously, but generally not before severe deformation and destruction of bone has occurred. Usually radiotherapy is not successful and is followed by local resection of the osteolytic process. Based on our presented case, we suggest early operative treatment to prevent severe damage.

Arthrodesis↗
PubMed1995

A novel assay for cytosolic 3-hydroxy-3-methylglutaryl-coenzyme A synthase activity using reversed-phase ion-pair chromatography: demonstration that Lifibrol (K12.148) modulates the enzyme activity.

Cytosolic HMG-CoA synthase and microsomal 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase catalyze two sequential steps in the mevalonate pathway. Both enzymes are negatively regulated by cholesterol. Cytosolic HMG-CoA synthase is responsible for the generation of HMG-CoA from acetyl-CoA and acetoacetyl-CoA). We have developed a new method to determine HMG-CoA synthase activity. In this assay, HMG-CoA is formed from acetoacetyl-CoA and labeled acetyl-CoA. The HMG-CoA product is isolated from the reaction mixture by means of reversed-phase ion-pair chromatography. The recovery of the product was always greater than 90%. The average within-batch coefficient of variation for HMG-CoA synthase activity was 5.1%. Using the new assay, we demonstrate that Lifibrol (K12.148), a new hypolipidemic compound, inhibits HMG-CoA synthase. Because our assay is accurate and precise it may become useful in future studies on the regulation and the pharmacological modulation of cytosolic HMG-CoA synthase.

Animals↗
PubMed1994

Polysaccharide conjugate vaccine responses in bone marrow transplant patients.

Bone marrow transplant patients have impaired responses to pure polysaccharide (PS) vaccines and are at an increased risk for disease caused by PS encapsulated pathogens such as Haemophilus influenzae type B (HIB) and Streptococcus pneumoniae. We immunized 35 BMT patients (21 allogeneic and 14 autologous) ages 2-45 years with pure PS pneumococcal (Pnu-imune 23) HIB-conjugate (HibTITER), and tetanus toxoid vaccines. Patients were assigned to receive vaccines at either 12 and 24 months after transplantation or at 24 months only. Only 19% of all enrolled patients developed protective antibody concentrations (> or = 0.300 microgram antibody nitrogen/ml) to the 6 pneumococcal serotypes measured after the 24-month immunization. Poor response to pneumococcal vaccine was not different for the 2 study groups and was similar to previous studies. In contrast, HIB-conjugate vaccine elicited protective concentrations of antibody (> or = 1.0 microgram/ml) in 56% of patients after 1 dose and in 80% after 2 doses. The group that received 2 doses of HIB-conjugate vaccine had a significantly higher geometric mean antibody concentration of 14.5 micrograms/ml as compared with 1.43 micrograms/ml for those receiving only 1 dose (P = 0.012). Responses to tetanus toxoid vaccine were similar to HIB-conjugate vaccine, with a booster response documented after the second dose. In summary, 2 doses of HIB-conjugate vaccine given at 12 and 24 months after transplantation produced protective antibody concentrations in 80% of patients. While the response to pure PS pneumococcal vaccine was poor, the results with HIB-conjugate vaccine suggest that future pneumococcal conjugate vaccines may also benefit BMT patients.

Adolescent↗
PubMed1994

Isolation of lipoprotein (a) using the regenerate of a dextran sulfate cellulose LDL apheresis system.

A simple method for the preparation of lipoprotein (a) is presented. The procedure uses the eluate of an LDL apheresis system operating on the basis of LDL adsorbing dextran sulfate cellulose. The eluate is concentrated by tangential flow membrane filtration and subjected to ultracentrifugation, first at a density of 1.125 kg/liter and then at 1.050 kg/liter. The crude lipoprotein (a)-containing fraction is chromatographed on agarose (Bio-Gel A-15m) to remove contaminating low-density and high-density lipoproteins. As demonstrated by immunoelectrophoresis with intermediate gel, the method provides lipoprotein (a) completely free of LDL. SDS-polyacrylamide gel electrophoresis showed that apolipoprotein E was associated with purified lipoprotein (a). On agarose gel electrophoresis and two-dimensional immunoelectrophoresis, lipoprotein (a) prepared by the proposed method cannot be distinguished from native lipoprotein (a). The major advantage of the procedure is that it allows the isolation of large amounts of lipoprotein (a) from a single donor.

Adsorption↗
PubMed1994

Elevated endothelin levels in patients with hyperlipoproteinemia.

We determined lipoproteins, apolipoproteins, and endothelin in 98 patients (58 female and 40 male, age 18-72 years) with hyperlipidemia (plasma cholesterol > 2.5 g/l and/or triglycerides > 2.0 g/l) and in 50 healthy subjects (20 female, 30 male, age 19-68 years). In patients with hyperlipidemia endothelin levels were elevated compared to healthy controls. Patients with plasma cholesterol above 2.5 g/l had higher endothelin and lipoprotein(a) concentrations than patients with plasma cholesterol levels less than 2.5 g/l. A positive correlation was found between the concentrations of endothelin and apolipoprotein B (r = 0.2137; P < 0.013). Smoking patients with lipoprotein (a) above 300 mg/l had higher endothelin levels than both nonsmoking patients with lipoprotein (a) above 300 mg/l and smokers with normal lipoprotein(a). In smokers endothelin correlated positively with Lp(a) (r = 0.709; P < 0.01). No correlation was found between endothelin and triglycerides nor between endothelin and age or sex. The results suggest that the vasoconstrictor endothelin contributes to the increased vasal tone in hyperlipidemia. Because endothelin also has mitogenic properties, it may play a relevant role in the development of premature atherosclerosis in patients with hyperlipidemia.

Adolescent↗
PubMed1994

Distribution of surgical pathology reports by a computer-driven telephone facsimile (FAX) device.

The current environment of medical economics increasingly mandates that written reports on surgical pathology specimens be distributed as soon as they are verified by responsible staff members and that they find their way infallibly to clinical physicians attending the patients in question. This brief overview describes the institutional experiences of the authors in managing this aspect of data delivery at large teaching hospitals. A system for FAX-transmittal of surgical pathology reports is described, used in conjunction with a commercial computer software package that was designed explicitly for anatomic pathology.

Hospitals, University↗
PubMed1994

A pathologist-designed imaging system for anatomic pathology signout, teaching, and research.

Pathology images are derived from gross surgical specimens, light microscopy, immunofluorescence, electron microscopy, molecular diagnostic gels, flow cytometry, image analysis data, and clinical laboratory data in graphic form. We have implemented a network of desktop personal computers (PCs) that allow us to easily capture, store, and retrieve gross and microscopic, anatomic, and research pathology images. System architecture involves multiple image acquisition and retrieval sites and a central file server for storage. The digitized images are conveyed via a local area network to and from image capture or display stations. Acquisition sites consist of a high-resolution camera connected to a frame grabber card in a 486-type personal computer, equipped with 16 MB (Table 1) RAM, a 1.05-gigabyte hard drive, and a 32-bit ethernet card for access to our anatomic pathology reporting system. We have designed a push-button workstation for acquiring and indexing images that does not significantly interfere with surgical pathology sign-out. Advantages of the system include the following: (1) Improving patient care: the availability of gross images at time of microscopic sign-out, verification of recurrence of malignancy from archived images, monitoring of bone marrow engraftment and immunosuppressive intervention after bone marrow/solid organ transplantation on repeat biopsies, and ability to seek instantaneous consultation with any pathologist on the network; (2) enhancing the teaching environment: building a digital surgical pathology atlas, improving the availability of images for conference support, and sharing cases across the network; (3) enhancing research: case study compilation, metastudy analysis, and availability of digitized images for quantitative analysis and permanent/reusable image records for archival study; and (4) other practical and economic considerations: storing case requisition images and hand-drawn diagrams deters the spread of gross room contaminants and results in considerable cost savings in photographic media for conferences, improved quality assurance by porting control stains across the network, and a multiplicity of other advantages that enhance image and information management in pathology.

Computer Systems↗
PubMed1994

Computer-assisted instruction in pathology residency training: design and implementation of integrated productivity and education workstations.

Computer-assisted instruction (CAI) has been significantly advanced by the development of inexpensive multimedia personal computers (PCs). As a part of efforts to integrate PC workstations as the primary interface to the anatomic pathology information system, we undertook an evaluation and implementation of image-based resident workstations drawing on technology and software now available. The goal was to develop an integrated diagnostic and research data center using PC workstations. After considerable analysis we implemented a Resident's Resource Center (RRC) to augment the training environment of the resident pathologist by providing productivity tools for the writing, research, and presentation needs of the trainee. We also provided video- and text-based education applications specifically tailored to the training pathologist. This led to the creation of two types of Windows-based workstations. The Productivity Workstation consists of a flatbed scanner, laser printer, and photorecorder connected to a 486-type PC. The Education Workstation consists of a high-resolution monitor and video disc player with bar code scanner connected to a 486-type PC. We briefly review the literature concerning CAI in pathology; outline the hardware, software, personnel and cost concerns that we faced in setting up our RRC; provide a partial list of vendors and programs currently on the market; review the software we have installed; and discuss the results of our efforts.

Computer Systems↗
PubMed1994

Effects of lovastatin (20-80 mg daily) on lipoprotein fractions in patients with severe primary hypercholesterolemia.

The effect of lovastatin on lipids, lipoproteins and apolipoproteins was studied in 10 patients with primary hypercholesterolemia. After four weeks diet/placebo alone, patients received diet plus lovastatin at daily doses of 20 mg (weeks 1-4), 40 mg (weeks 5-8) and 80 mg (weeks 9-12). Twelve weeks of treatment with lovastatin resulted in a lowering of total cholesterol and LDL-cholesterol by 34% and 41%, respectively. Triglycerides and VLDL-cholesterol decreased by 19% and by 42%, respectively. HDL-cholesterol and HDL2-cholesterol increased, whereas HDL3-cholesterol was not affected. IDL-cholesterol decreased by 50%, suggesting that the clearance of remnant lipoproteins was enhanced by lovastatin. In the VLDL and the IDL fraction, the triglyceride to cholesterol mass ratio increased significantly after twelve weeks of therapy. Lipoprotein(a) was not affected. Lovastatin was well tolerated and the data shows that lovastatin exerts favorable effects on plasma lipoprotein fractions. It may, therefore, prove a useful drug in the primary and secondary prevention of atherosclerotic vessel diseases.

Adult↗