Biomedical subjects

B Wolf

Publications and source records attributed to B Wolf.

At least 19 recordsLinked to original sources

PubMed1992

Glycogen storage disease type III (glycogen debranching enzyme deficiency): correlation of biochemical defects with myopathy and cardiomyopathy.

OBJECTIVE: To determine whether a specific subtype of glycogen storage disease type III is associated with myopathy and cardiomyopathy. DESIGN: Case series. SETTING: Three referral medical centers. PATIENTS: All patients with glycogen storage disease type III who were followed in 1990 and for whom both immunoblot analysis and clinical data were available. MAIN OUTCOME MEASURES: Evaluation for myopathy and cardiomyopathy included determinations of serum creatine kinase activity; muscle strength testing; ischemic exercise testing; nerve conduction studies; and electromyographic, electrocardiographic, and echocardiographic studies. RESULTS: Three patients with deficient debranching enzyme activity and deficient immunoreactive material in liver but normal debranching enzyme activity in muscle (glycogen storage disease IIIb) had no clinical evidence of myopathy or cardiomyopathy. Serum creatine kinase activity, muscle strength, ischemic exercise testing, electrocardiograms, and echocardiograms were normal in these patients. These studies and electromyograms were abnormal in seven patients with total debranching enzyme deficiency and an absence of immunoreactive material in both liver and muscle (glycogen storage disease IIIa) and in three patients who had debranching enzyme transferase deficiency but normal glucosidase activity in both liver and muscle (glycogen storage disease IIId). All 10 of these patients had progressive myopathy, and 6 had progressive cardiomyopathy. CONCLUSION: Clinical features of glycogen storage disease type III correlate with the particular biochemical defect seen with the disorder. Assessments of debranching enzyme or debranching enzyme transferase activity in muscle can be used to predict whether patients with glycogen storage disease type III will develop myopathy and cardiomyopathy.

Adolescent↗

PubMed1992

Progressive bilateral nasal alar collapse: a dominantly inherited trait.

We describe a 47-year-old woman with progressive bilateral collapse of the alae nasi first noted at age 16 years. Her dizygotic twin daughters have similar nasal collapse beginning at age 20 years. This condition appears to be inherited as a dominant trait. Although plastic surgical correction has been successful for a phenotypically similar condition due to trauma, surgical correction must be considered cautiously in individuals with an atraumative, possibly inherited, progressive form of the disorder.

Adult↗

PubMed1992

Influence of cryopreservation on viability and nutritional microcirculation of islets of Langerhans.

Isolated pancreatic islets of Syrian golden hamsters were cryopreserved for 1 and 10 weeks, respectively. Following thawing islet mass was found more than 90%. Analysis of viability of these islets by dithizone staining revealed 94 +/- 4% (1 week cryopreservation) and 96 +/- 3% (10 weeks cryopreservation) positively stained islets. After implantation into dorsal skin-fold chambers of syngeneic animals, intravital fluorescence microscopy (5% FITC-dextran, i.v.) showed a regular microvascular network 10 days after implantation. The total diameter of the microvascular network was found similar in cryopreserved islets (day 10: 420.8 +/- 55.2 microns (1 week preservation) and 406.5 +/- 25.2 (10 weeks preservation)) as compared to non-preserved controls (day 10: 411.7 +/- 53.9 microns). Therefore we conclude that cryopreservation of hamster islet isografts for 1 and 10 weeks, respectively, does not alter viability as well as the potential for revascularization. Cryopreservation seems to be an adequate technique for long time storage prior to free transplantation.

Animals↗

PubMed1992

[Modeling in biology. Structured analysis of intracellular calcium oscillations in electrically non-excitable cells].

In this paper a systematic approach to the mathematical modeling of intracellular Ca2+ oscillations is introduced. After a structured analysis a stochastic model of the system is derived which is numerically tractable by means of a stochastic simulation. A critical discussion of theoretical models for Ca2+ oscillations reveals that not all of the proposed mechanisms are consistent with experimental data. In addition, a model for oscillatory calcium waves is presented. Uncovering these mechanisms facilitates the design of anti-mitotic drugs interfering with Ca2+ metabolism.

Animals↗

PubMed1992

Glycogen debranching enzyme deficiency: long-term study of serum enzyme activities and clinical features.

In glycogen storage disease type III (glycogen debranching enzyme (DE) deficiency), the activities of serum alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase may be strikingly elevated during childhood but are low during adult life. To determine the pattern of the elevated serum enzyme activities in relationship to diet, the biochemical subtype and clinical symptoms, 13 patients with DE deficiency were studied. Activities of serum aspartate and alanine transaminases, lactate dehydrogenase, and alkaline phosphatase were markedly elevated during infancy. Continued elevation of enzyme activities during childhood appeared to be related to DE deficiency in liver, but unrelated to DE deficiency in muscle. Activity elevations correlated inconsistently with diet and poorly with childhood growth rate or the presence of hypoglycaemia. The serum enzyme activities declined around puberty concomitantly with a decrease in liver size. Although periportal fibrosis and micronodular cirrhosis indicated the presence of hepatocellular damage during childhood, the decline in serum enzyme activities with age and the absence of overt hepatic dysfunction suggest that the fibrotic process may not always progress.

Adolescent↗

PubMed1992

Immunohistochemical localization of human immunodeficiency virus p24 antigen in placental tissue.

As human immunodeficiency virus (HIV) infection spreads into the heterosexual population, perinatally acquired HIV infection will increase in incidence, and knowledge of the mechanism of this transfer is important. We have used immunoperoxidase techniques to detect HIV p24 antigen in formalin-fixed, paraffin-embedded placental tissue from nine known HIV serologically positive mothers. In four of these cases we have detected evidence or viral antigen in placental Hofbauer cells, vascular endothelium, or intermediate trophoblast. The implications for understanding the mode of transfer of infection to the fetus are discussed.

Female↗

PubMed1992

Structured Biological Modelling: a method for the analysis and simulation of biological systems applied to oscillatory intracellular calcium waves.

In biology signal and information processing networks are widely known. Due to their inherent complexity and non-linear dynamics the time evolution of these systems can not be predicted by simple plausibility arguments. Fortunately, the power of modern computers allows the simulation of complex biological models. Therefore the problem becomes reduced to the question of how to develop a consistent mathematical model which comprises the essentials of the real biological system. As an interface between the phenomenological description and a computer simulation of the system the proposed method of Structured Biological Modelling (SBM) uses top-down levelled dataflow diagrams. They serve as a powerful tool for the analysis and the mathematical description of the system in terms of a stochastic formulation. The stochastic treatment, regarding the time evolution of the system as a stochastic process governed by a master equation, circumvents most difficulties arising from high dimensional and non-linear systems. As an application of SBM we develop a stochastic computer model of intracellular oscillatory Ca2+ waves in non-excitable cells. As demonstrated on this example, SBM can be used for the design of computer experiments which under certain conditions can be used as cheap and harmless counterparts to the usual time-consuming biological experiments.

Calcium↗

PubMed1992

Comparison of profound biotinidase deficiency in children ascertained clinically and by newborn screening using a simple method of accurately determining residual biotinidase activity.

We describe a method for more accurately determining residual biotinidase activity in sera of individuals with profound biotinidase deficiency. Using this method we found that there is a statistically significant difference in the means of residual serum enzyme activities of symptomatic children and those identified by newborn screening. A subgroup of children identified by screening have activities higher than any of the symptomatic population. These children may develop mild symptoms, may develop symptoms later in life, or may not develop symptoms at all.

Amidohydrolases↗

PubMed1992

In vitro activation of peripheral mononuclear cells by zinc in HIV-infected patients and healthy controls.

Zinc is a mitogen for peripheral blood mononuclear cells (PBMC). The optimal mitogenic concentration was found to be 0.05 mmol/l (327 micrograms/dl), four times higher than physiological serum levels. Maximal proliferation was observed after 6 days. Limited dilution technique revealed a frequency of zinc reactive cells of 1:3467 (median; range 1:1628-1:6235). Cord blood mononuclear cells from four of six healthy children could be stimulated to proliferate by zinc. A normal zinc-induced proliferative response could be demonstrated in all six HIV-infected patients in the Walter-Reed-stage I, in nine of 11 patients in Walter-Reed II and in only two of five patients in Walter-Reed III. In Walter-Reed IV to VI all eight patients showed a weak response to zinc (less than 50% of the healthy day control). Decreased zinc serum levels were found in 10 of 28 patients and in one of 16 controls. There was a significant correlation of a diminished zinc-induced proliferation with lower serum levels of zinc and a reduced proportion of CD4 helper cells in HIV-1-infected men. Because of a suppression of mitogenesis by high dose of zinc an excessive intake of zinc as used by some HIV-1-infected patients can presently not be recommended. The value of zinc-induced proliferation for monitoring HIV-infected patients has still to be established.

Cells, Cultured↗

PubMed1992

Cryopreservation of islets of Langerhans does not affect angiogenesis and revascularization after free transplantation.

Cryopreservation of isolated islets of Langerhans will be a necessary procedure if pancreatic islet transplantation crosses the threshold for clinical treatment of diabetes mellitus. Although successful cryopreservation of rodent, canine, porcine and human islets has been documented in the past few years, little is known about the influence of the freeze-thaw procedure on the islet's potential to induce angiogenesis and revascularization, a process which is of crucial importance after free transplantation. We have analyzed the process of revascularization of 1- and 10-week-cryopreserved hamster islet isografts using intravital fluorescence microscopy. First signs of angiogenesis of cryopreserved islet grafts were observed on day 2 after transplantation, characterized by the protrusion of capillary sprouts. During the following days these sprouts formed a microvascular network, and revascularization was completed on day 10 after transplantation. Quantitative analysis of functional capillary density, capillary red blood cell velocity, capillary diameter and flow of individual capillaries did neither show differences between 1- and 10-week-cryopreserved islets, nor differences between cryopreserved islets and islets transplanted without cryopreservation were observed. From these results we conclude that cryopreservation of isolated pancreatic islet grafts is an adequate technique for long-term storage prior to transplantation.

Animals↗

PubMed1992

Biochemical and immunologic characterization of serum biotinidase in partial biotinidase deficiency.

Newborn screening for biotinidase deficiency has identified children with profound biotinidase deficiency (less than 10% of mean normal activity) and about an equal number of children with partial biotinidase deficiency (10 to 30% of mean normal activity). Partial biotinidase deficiency was initially considered a variant without clinical consequences until one child, during an episode of gastroenteritis, developed symptoms of biotinidase deficiency that resolved with biotin therapy. Biochemical and immunologic characterization of biotinidase was performed in sera from 23 children with partial biotinidase deficiency from 19 families and 18 of their parents. As expected, all patients had cross-reacting material in their serum. Patients with partial biotinidase deficiency can be classified into six distinct biochemical phenotypes on the basis of the number of isoforms and the distribution frequency of the isoforms. Kinetic studies were performed on samples from 17 of the patients and were found to be normal in all cases. The patient with partial deficiency who became symptomatic has an isoform profile that is not different from 10 other asymptomatic, partially deficient children. The parents had normal isoform patterns. The isoform patterns observed in the patients with partial biotinidase deficiency were not different from those of the profoundly deficient patients who had cross-reacting material.

Adult↗

PubMed1992

Tracheal papilloma presenting as asthma in a child.

This report describes a child with a tracheal papilloma who was initially diagnosed and treated as having asthma. The case illustrates that all wheezing in children should not be attributed to asthma.

Bronchoscopy↗

PubMed1992

Subjective and behavioral effects of diphenhydramine, lorazepam and methocarbamol: evaluation of abuse liability.

The effects of orally administered placebo, diphenhydramine, lorazepam, methocarbamol and placebo were studied in volunteers with histories of recreational substance abuse including sedative/hypnotics. Placebo, diphenhydramine (100, 200 and 400 mg), lorazepam (1 and 4 mg) and methocarbamol (2.25 and 9 g) were tested in a randomized, double-blind crossover study using 14 subjects. Psychomotor and cognitive performance and subject- and observer-rated responses were measured daily before and for 5.5 hr after drug administration. The results showed that each of the drugs exhibited a different profile of effects on the test battery. Lorazepam produced significant increases in subjects' ratings of drug effect and liking, increases in measures of sedation and impairment of psychomotor performance. Methocarbamol also produced significant increases in subjects' ratings of drug effect and liking and measures of sedation, but it produced only minor impairment of psychomotor and cognitive performance. Diphenhydramine increased subjects' and observers' ratings of drug effect and measures of sedation, but it produced less psychomotor performance impairment and liking than lorazepam. Diphenhydramine produced the most side effects. The present study clearly differentiated the behavioral and subjective profiles of diphenhydramine, lorazepam and methocarbamol. Consistent with its recognized low abuse liability, diphenhydramine produced fewer increases in measures of positive mood and more adverse effects. The considerable overlap in subjective effect measures of positive mood make further differentiation with respect to abuse liability difficult.

Adult↗

PubMed1992

[The use of bead cellulose for controlled drug liberation. 4. Binding of bead cellulose and bead cellulose-derivatives with prazosin hydrochloride and its liberation].

Pure bead cellulose and the ionic derivatives carboxymethyl and dihydrogen phosphate bead cellulose were coupled with prazosin hydrochloride. The degree of substitution achieved during loading mostly depends on the number of functional groups, what was verified by titrimetric determination of the ion exchange capacity. Because of predominant ionic binding of the protonated prazosin cation to the anionic groups of several types of bead cellulose in electrolytes containing liquids as well as in water a large amount of bonded drug is liberated considerable fast. Retardation of the liberation in comparison to the commercial product Adversuten is verified but not applicable to therapeutic use in the case of prazosin.

Cellulose↗

PubMed1992

[The use of bead cellulose for controlled drug liberation. 5. Kinetics of liberation of bonded drugs from bead cellulose and bead cellulose derivatives].

Examination of in vitro liberation of prazosin hydrochloride and benzocaine from formulations of matrix type with bead cellulose and bead cellulose derivatives shows deviations from first order kinetics owing to competition of several processes: dissociation of ionic bonds or cleavage of covalent bonds between drugs and bead cellulose, pore diffusion, dissolution of the drugs and swelling of cellulose matrix. Suitable combinations of different bonded portions of the drug on bead celluloses let these complexes seem to be successful in the use for controlled and retarded liberation of drugs.

Cellulose↗

PubMed1992

[The use of bead cellulose for controlled drug liberation. 5. Binding of benzocaine as a model drug to dialdehyde-bead cellulose and its in vitro liberation].

In the case of ionic binding of drugs to bead cellulose and its derivatives there was no pronounced retardation obvious. Because of this lack benzocaine as a model drug was covalent bound to dialdehyde bead cellulose by an azomethine bond in analogy with enzyme immobilisation methods. The rate of liberation in phosphate buffer was low and incomplete compared with the dissolution rate of pure benzocaine under the same conditions. A further decrease of liberation rate was obtained by reduction of the azomethine to the amine bond. Retardation of drug liberation strictly speaking was not achieved. The main amount of liberated drug was liberated during the first 20 min, but after 6 h the rate was still under 50% of the drug available. The physical properties of the beads like spherical shape and porosity are not significantly influenced by oxidation of cellulose and by loading with drug.

Benzocaine↗

PubMed1992

Rapid alterations in the plasma membrane structure of macrophages stimulated with bacterial lipopeptides.

Synthetic lipopeptide analogues of the N-terminal region of bacterial lipoprotein are potent activators of macrophages. In a previous study we showed that within minutes after their addition to macrophage cultures, lipopeptides were found attached to the plasma membranes and within different compartments of the cells. Their rapid interaction with the plasma membrane is thought to occur via the insertion of their three fatty acids. We used the freeze-fracture technique to study the influence of lipopeptides on the architecture of plasma membranes. Fifteen to thirty seconds after addition of the lipopeptides, the freeze-fractured plasma membranes show a rapid decrease in the particle density. This effect is not due to a loss of proteins, but is caused by lateral diffusion of single particles, which subsequently aggregate. These alterations are transient, temperature-sensitive and disappear 20 min after stimulation. At 4 degrees C, no change is found in the architecture of the plasma membranes. Using electron energy loss spectroscopy (EELS), lipopeptides can neither be detected on the membrane nor within the cells when incubated at this temperature. Our findings suggest that membrane protein aggregation is involved in the rapid uptake of lipopeptides into macrophages after their interaction with the plasma membranes.

Amino Acid Sequence↗

PubMed1992

Biochemical and immunological characterization of serum biotinidase in profound biotinidase deficiency.

The biochemical and immunological characterization of biotinidase was performed in sera from 100 normal individuals, 68 children with profound biotinidase deficiency (less than 10% of mean normal activity) who were identified symptomatically and by newborn screening, and 63 of their parents. On isoelectric focusing, serum enzyme from normal individuals exhibits extensive microheterogeneity, consisting of at least four major and five minor isoforms at pH 4.15-4.35. Patients with profound biotinidase deficiency can be classified into at least nine distinct biochemical phenotypes, on the basis of (a) the presence or absence of cross-reacting material (CRM) to biotinidase, (b) the number of isoforms, and (c) the distribution frequency of the isoforms. None of the patients with CRM had an abnormal Km of the substrate for the enzyme. All of the parents had normal isoform patterns. The mean activities, CRM concentrations, and specific activities were not significantly different between parents of CRM-positive children and parents of CRM-negative children. There is no relationship between either the age at onset or the severity of symptoms and the isoform patterns or CRM status of the symptomatic children. The isoform patterns of children identified by newborn screening are not different from those of symptomatic children.

Adult↗