Parallel supercomputers for lattice gauge theory.

During the past 10 years, particle physicists have increasingly employed numerical simulation to answer fundamental theoretical questions about the properties of quarks and gluons. The enormous computer resources required by quantum chromodynamic calculations have inspired the design and construction of very powerful, highly parallel, dedicated computers optimized for this work. This article gives a brief description of the numerical structure and current status of these large-scale lattice gauge theory calculations, with emphasis on the computational demands they make. The architecture, present state, and potential of these special-purpose supercomputers is described. It is argued that a numerical solution of low energy quantum chromodynamics may well be achieved by these machines.

Adrenoleukodystrophy: a link between adrenal insufficiency and school performance.

The combination of neurodevelopmental regression and adrenal insufficiency should alert practitioners or emergency room physicians about ALD. Although still unproven, early medical intervention with either gene therapy or bone marrow transplantation may offer more promise to these patients.

The design of a diet restricted in saturated very long-chain fatty acids: therapeutic application in adrenoleukodystrophy.

Adrenoleukodystrophy is an inherited, progressive disorder of the CNS white matter and adrenal glands, associated with the pathognomonic accumulation of saturated very long-chain fatty acids, particularly C26:0. It has been previously demonstrated that the fatty acids that accumulate in adrenoleukodystrophy are, at least in part, of dietary origin. This observation, coupled with success of dietary phytanic acid restriction in a related disorder, Refsum's disease, encouraged us to develop a diet that would restrict dietary C26:0 intake. We report here the very long-chain fatty acids content of 135 common foods and development of a diet that restricts C26:0 intake to 3 mg, compared to 12 to 40 mg in the standard American diet. To limit C26:0 intakes it was found necessary to restrict fatty foods and the outer coverings of vegetables and fruits. In contrast to the success of phytanic acid restriction in limiting disease progress in Refsum's patients, administration of the very long-chain fatty acid-restricted diet to seven adrenoleukodystrophy patients for 3- to 24-month periods was found to be ineffective in lowering their plasma very long-chain fatty acids or in improving clinical status. Recently endogenous synthesis of C26:0 has been demonstrated and this may account for the failure of dietary therapy in adrenoleukodystrophy. It is possible that dietary restriction may augment other therapies in the future.

Acquired reversible autistic syndrome in acute encephalopathic illness in children.

In seeking the neurologic substrate of the autistic syndrome of childhood, previous studies have implicated the medial temporal lobe or the ring of mesolimbic cortex located in the mesial frontal and temporal lobes. During an acute encephalopathic illness, a clinical picture developed in three children that was consistent with infantile autism. This development was reversible. It was differentiated from acquired epileptic aphasia, and the language disorder was differentiated aphasia. One child has rises in serum herpes simplex titers, and a computerized tomographic (CT) scan revealed an extensive lesion of the temporal lobes, predominantly on the left. The other two, with similar clinical syndromes, had normal CT scans, and no etiologic agent was defined. These cases are examples of an acquired and reversible autistic syndrome in childhood, emphasizing the clinical similarities to bilateral medial temporal lobe disease as described in man, including the Klüver-Bucy syndrome seen in postencephalitic as well as postsurgical states.

Immunologic dysfunction: simultaneous study of Alzheimer's and older Down's patients.

Peripheral blood lymphocytes from Alzheimer's disease patients, older patients (aged 25-59 years) with Down's syndrome and closely age-matched healthy controls were tested in vitro for DNA synthesis in response to stimulation by phytohemagglutinin, pokeweed mitogen and OKT3 monoclonal antibody to T3 antigen. All were significantly decreased in Down's and Alzheimer's patients relative to healthy controls. The autologous mixed lymphocyte reaction (AMLR), unstimulated or stimulated with anti-T3. in the 2 patient groups did not differ significantly from the healthy controls. We also quantified the proportions of the T cells staining positive for surface membrane orosomucoid, and found their levels to be either higher or lower than normal in Down's patients, but not in Alzheimer's patients. These results demonstrate the existence of defective cellular immune functions in both elderly Down's patients and Alzheimer's patients.

Familial spastic paraparesis: an adrenoleukodystrophy phenotype?

Adrenoleukodystrophy (ALD) must be considered in the diagnosis of men with progressive nervous system disease. We found the biochemical defect characteristic of ALD in two brothers with spastic paraparesis of late adult onset. Family study then revealed other affected men and asymptomatic heterozygotes in a pattern that conformed to an X-linked pattern of inheritance.

Bone marrow transplant in adrenoleukodystrophy.

An allogeneic bone marrow transplant (BMT) from a normal HLA identical sibling donor was performed in a 13-year-old boy with rapidly progressive adrenoleukodystrophy (ALD). Engraftment and complete hematologic recovery occurred within 4 weeks, but neurologic deterioration continued. The patient died of an adenovirus infection 141 days after BMT. ALD is characterized by abnormally high plasma levels of very long chain fatty acids (VLCFA) as a result of impaired capacity to degrade them. Ten days after BMT, the white blood cell VLCFA levels and enzyme activity became normal; after 3 months, there was progressive reduction of plasma VLCFA to levels only slightly above normal.

Intellectual and adaptive functioning in individuals with Down syndrome in relation to age and environmental placement.

The cognitive and adaptive capacities of 130 individuals with Down syndrome were investigated as a function of age and environmental placement. Intellectual deterioration occurred whether individuals resided at home or in an institutional setting. Social/adaptive deterioration also occurred but with the least decline for those individuals who resided in institutional settings.

Cognitive, adaptive, and behavioral characteristics of Williams syndrome.

Williams syndrome is a genetic disorder linked to cognitive and behavioral patterns of varying consistency; this study was conducted to clarify further the strengths and weaknesses of children with Williams syndrome. Fifteen subjects with the characteristic features of Williams syndrome were evaluated using the Stanford-Binet Intelligence Scale for Children, Fourth Edition; the Vineland Adaptive Behavior Scales, Interview Edition; and the Child Behavior Checklist. Cognitive skills ranged from the Moderate Range of Mental Retardation to the Low Average range, with relative strengths in nonverbal and quantitative reasoning. Adaptive skills were delayed, with strengths in communication and socialization. Behaviorally, clinically significant levels of attention problems, borderline-significant levels of social and thought problems, and significantly low levels of social contacts and structured activities were found. In contrast to the findings of many other studies of Williams syndrome, language skills and short-term memory skills were weak. Children with Williams syndrome may present a more evenly developed intellectual profile, with verbal and nonverbal skills being commensurate. In conclusion, a variety of cognitive, adaptive, and behavioral patterns have been shown to be possible in Williams syndrome; therefore, a single predictable cognitive or behavioral phenotype cannot be assumed.

Administration of iduronate sulfatase by plasma exchange to patients with the Hunter syndrome: a clinical study.

The Hunter syndrome (MPS II) is the only mucopolysaccharidosis in which there is appreciable activity of the deficient enzyme in normal plasma. We performed enzyme-replacement treatment by plasma exchange in five Hunter syndrome children. Carefully monitoring the cardiovascular status, we administered monthly single plasma volume exchanges for a 3 to 8 mo period. The results indicate a substantial gain of enzyme activity, persisting with a t50% = 19 +/- 5 hr. The maximal level and persistence of increased enzyme activity did not change after repeated exchanges, suggesting that immune responses were not elicited. Despite this, no demonstrable clinical benefit was apparent when the study group was compared with an age-matched control group of Hunter syndrome patients.

Effect of proteolipid protein on central nervous system myelin membrane fluidity.

The effect which intrinsic (proteolipid) protein has on fluidity of central nervous system myelin membrane was measured through differences in temperature-dependent anisotropy of the lipid-soluble fluorescence probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), in multilamellar vesicles (MLV) prepared from total myelin lipids in the presence and absence of proteolipid protein. Very little difference was observed in the anisotropies of DPH incorporated into intact myelin membrane vesicles compared with MLV reconstituted from total myelin lipid plus proteolipid protein but excluding myelin basic protein. In contrast, a significant decrease (P less than 0.01) in anisotropy was observed when MLV prepared from total myelin lipids depleted of proteolipid protein were compared with vesicles containing proteolipid protein. Given the different distributions of myelin basic protein and proteolipid protein suggested by freeze-fracture, neutron and X-ray diffraction studies, and the fact that the hydrophobic DPH probe is known to distribute in the non-polar regions of lipid bilayers, we interpret the marked decrease in anisotropy when proteolipid protein is excluded from MLV to suggest that at least part of the proteolipid is distributed in the hydrocarbon region of the MLV. These findings are consistent with the earlier physical studies and recent postulations that extensive hydrophobic segments exist in proteolipid protein and that these hydrophobic segments are buried in the myelin lipid bilayer and alternate with hydrophilic extra-membrane segments.

Ocular histopathologic studies of neonatal and childhood adrenoleukodystrophy.

Histopathologic studies of the eyes of one patient (a boy who died at 14 years of age) with childhood adrenoleukodystrophy and two patients (girls who died at 24 and 31 months of age) with neonatal adrenoleukodystrophy showed the accumulation of the characteristic bileaflet inclusions in optic nerve macrophages, retinal neurons, and macrophages and loss of ganglion cell and nerve fiber layer. Additionally, in the two cases of neonatal adrenoleukodystrophy, changes resembling early retinitis pigmentosa were found, with accumulation of characteristic inclusions in the retinal pigment epithelium and pigment-laden macrophages. One of the patients with neonatal adrenoleukodystrophy also had an anterior subcapsular cataract and cystoid macular edema.

Ocular histopathologic and biochemical studies of the cerebrohepatorenal syndrome (Zellweger's syndrome) and its relationship to neonatal adrenoleukodystrophy.

The eyes of three infants with cerebrohepatorenal disease (Zellweger's syndrome) who died demonstrated ganglion cell loss, gliosis of the nerve fiber layer and optic nerve, optic atrophy, and changes resembling those of retinitis pigmentosa in the retina and pigment epithelium. Ultrastructural examination showed bileaflet inclusions identical to those seen in neonatal adrenoleukodystrophy in the pigment epithelium and in pigmented macrophages, but these were absent in the cornea. Biochemical analysis of tissues demonstrated an excessive amount of very-long-chain fatty acids in the ocular tissues, an abnormality also found in adrenoleukodystrophy. These histopathologic and biochemical results demonstrated that the cerebrohepatorenal syndrome and neonatal adrenoleukodystrophy are similar in regard to ocular abnormalities and the presence of saturated very-long-chain fatty acids.

A case study of the cognitive and behavioral deficits of temporal lobe damage in herpes simplex encephalitis.

Herpes simplex viral encephalitis is a fairly common nonepidemic encephalitis which produces severe neurological sequelae in survivors. Most viral infections of the central nervous system produce diffuse damage, but the herpes simplex virus demonstrates a predilection for localization in the temporal and orbitofrontal regions of the brain. This case study illustrates the highly significant language difficulties, marked memory deficits, and propensity for physical aggression following temporal lobe damage brought about by herpes encephalitis, and presents the usefulness of a new diagnostic measure in delineating such a variable cognitive pattern.

Kinetics of the dissolution of copper metal in aqueous solutions containing unsaturated organic ligands and copper(II).

The kinetics of the dissolution of copper metal in an aqueous solution containing copper(II) and an unsaturated organic ligand was followed by using an automated flow-injection analysis technique to determine the concentration of copper(I) in solution as a function of time. The results suggest that the rate of dissolution of the copper metal is dependent on electron transfer between the copper(II) and copper atoms on the surface of the copper metal, and on the stabilization of copper(I) by the unsaturated organic ligand in solution.

Independent origins of the internal and external carotid arteries--a case report.

A case illustrating a congenital anomaly in the development of the left carotid artery is presented. The common carotid artery was found to be absent, with both internal and external carotid arteries arising separately from the aortic arch. This is a rare occurrence that is described angiographically and embryologically.

Nursing mothers service: a community breast-feeding program.

An upward trend in breast feeding has been seen in recent years, and health care providers must take an active role in providing services to lactating women if this trend continues. A nurse managed, hospital-based, breast-feeding program that provides continuity of care and supportive services from the hospital to the community for lactating women is described.

Prediction of nosocomial infections in cardiac patients: a pilot study.

The purpose of this descriptive pilot study was to discover and correct problems with data collection in the identification of variables that are the strongest predictors of the occurrence of four nosocomial infections in cardiac patients. Data from 29 subjects who were admitted to a critical care unit (CCU) were tracked at a health care facility located in upstate New York. Data were obtained from daily care flow sheets and patients' charts. Although most results were not statistically significant, trends were identified in the data. The 7 patients who developed nosocomial infections were men who were older than 50 years, underwent a cardiac surgical or other invasive procedure, had more than one intravenous catheter, experienced a significant event in the CCU, and received prophylactic antibiotics. It is recommended that the number of independent variables tracked be reduced to 20. In addition, readmission of subjects whose data are being tracked should be included.

Synthesis of gold(I) fluoroalkyl and fluoroalkenyl-substituted phosphine complexes and factors affecting their crystal packing.

A series of gold(I) phosphine complexes of the type [AuCl{PR(2)(R(f))}] (R = Et, i-Pr, Cy; R(f) = CF = CF(2); R = Ph, R(f) = C = CFH, CCl = CF(2), C ≡ CCF(3), CF(3), i-C(3)F(7), s-C(4)F(9)) have been prepared and most have been structurally characterised. All of the complexes are monomeric in the solid state, and a number of secondary interactions are observed--including short intramolecular AuF distances, metal-bound Au-ClH non-classical hydrogen bonds, fluorous domains and phenyl embraces. Only in the case of [AuCl{PEt(2)(CF = CF(2))}] is an aurophilic interaction with an AuAu contact less than the sum of the van der Waals radii observed. Even then, the distance, 3.3458(10) Å, is longer than that previously observed for the related complex with R = Ph; R(f) = CF = CF(2).