Electronic structure of lithium beryllium hydride.
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Journal Article↗
Biomedical subjects
S Hill
Publications and source records attributed to S Hill.
Neurologic complications in long-standing nephropathic cystinosis.
The central nervous system has been considered to be uninvolved in nephropathic cystinosis. Survival into adulthood, following renal dialysis and transplantation, has brought attention to the sequelae of long-standing cystinosis. We examined 14 patients with cystinosis, 12 of whom had undergone renal transplantation. Two patients had neurologic symptoms. One patient had progressive bradykinesia, dementia, and spasticity with computed tomographic scan evidence of cerebral atrophy and multifocal mineralization in bilateral internal capsules and periventricular white matter. One patient had behavioral and, to a lesser extent, cognitive disturbance and computed tomographic scan evidence of marked, progressive cerebral atrophy. Although the remaining patients had normal results of neurologic examinations, 11 had roentgenographic evidence of generalized cerebral atrophy; 2 of these had abnormal electroencephalograms, 1 had borderline-deficient intellectual function, and 2 had computed tomographic scan evidence of multifocal, intracerebral mineralization. The patients with nervous system abnormalities were not distinguished by patterns of medication use, demographic or laboratory features, or the relative severity of cystinosis. Although the neurologic involvement in these patients suggests that cystinosis may eventually involve the central nervous system, the differential diagnosis must include other complications from renal failure, dialysis, and immunosuppression.
Adolescent↗
Handwashing practices in an intensive care unit: the effects of an educational program and its relationship to infection rates.
Handwashing is the single most important procedure in the prevention of nosocomial infections and yet it remains the most violated of all infection control procedures. With a sequential intervention study in an intensive care unit we have demonstrated that poor handwashing practices are associated with a high nosocomial infection rate, whereas good handwashing practices are associated with a low nosocomial infection rate. An educational and enforcement program designed to improve handwashing procedures can significantly reduce endemic nosocomial infection rates.
Adolescent↗
Vascular collapse after flavone acetic acid: a possible mechanism of its anti-tumour action.
Flavone acetic acid (FAA, LM 975) causes regression and growth retardation in several solid murine tumours. The mechanism of action is unknown, although various lines of evidence suggest an indirect cytotoxic effect. We have carried out preliminary studies on the effect of FAA on relative blood flow in six experimental murine tumours using 86RbCl extraction. We have also measured growth delay after treatment with the same dose of FAA (200 mg/kg). The data show that the drug induces a drop in tumour perfusion within 6 h of treatment in all of the tumours, and that this can be correlated with the growth delay measured. We conclude that vascular collapse may be an important component of the action of this drug, and that further investigation of this phenomenon is warranted.
Animals↗
Mechanisms of fibre-induced superoxide release from alveolar macrophages and induction of superoxide dismutase in the lungs of rats inhaling crocidolite.
Asbestos resembles the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), in its ability to elicit release of superoxide (O2-.) from rodent alveolar macrophages (AM) in vitro. In addition, superoxide dismutase (SOD), the antioxidant enzyme scavenging O2-, is increased in cultures of tracheobronchial epithelial cells and lung fibroblasts after exposure to either crocidolite or chrysotile asbestos. Our objectives here were to determine: (1) the chemical and physical properties of asbestos important in the generation of O2- from rat AM; and (2) the effects of O2- in comparison with asbestos on biosyntheses of collagen and non-collagen protein in rat lung fibroblasts in vitro. We were also interested in whether increased production of SOD occurred in the lungs of rats after inhalation of crocidolite asbestos. To determine whether O2- was elicited in response to a variety of asbestiform fibres, AM lavaged from Fischer 344 rat lungs were exposed in vitro to equivalent non-toxic amounts of crocidolite asbestos, erionite, Code 100 fibreglass, sepiolite, and their non-fibrous analogues, riebeckite, mordenite and glass particles. In addition, sized preparations of long (greater than 10 microns) and short (less than 2 microns) asbestos were introduced at identical concentrations to determine whether length of fibres is critical in O2- release. The amount of O2- released from AM in response to dusts was then determined by measuring SOD-inhibitable reduction of cytochrome C. All asbestiform fibres caused a significant (p less than 0.05) increase in generation of O2- from epithelial cells, whereas non-fibrous particles were less active at comparable concentrations. Experiments with long (greater than 10 microns) versus short (less than 2 microns) chrysotile showed that long fibres caused a more striking, dosage-dependent release of O2-. To determine whether O2- plays a role in the causation of fibrotic lung disease, rat lung fibroblasts were exposed to a biochemical generation system (xanthine-xanthine oxidase) for O2- before quantitation of cell-associated collagen and non-collagen protein at 24, 48 and 72 h thereafter. At the latter time periods, significant increases in total collagen per ng DNA were observed. In comparison with controls, the generation system for O2- also caused an initial decrease in synthesis of non-collagen protein followed by increases in synthesis of non-collagen protein at 48 and 72 h.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Midline granuloma due to illicit cocaine use.
The successful treatment of patients with midline granuloma requires prompt recognition of the cause as the therapy is quite specific. Nasal insufflation of cocaine is rarely mentioned as a cause. Two patients are described who used intranasal cocaine, leading to midline ulceration of the upper respiratory tract.
Adult↗
Dense metaphyseal bands and growth arrest associated with isotretinoin therapy.
A 9-year-old boy, treated with high-dose isotretinoin therapy for fibrodysplasia ossificans progressiva, developed dense metaphyseal bands and growth arrest. Discontinuance of isotretinoin therapy was followed by gradual decrease of metaphyseal bands and resumption of clinical growth. The dense metaphyseal bands may be related to the known action of retinoids as modulators of chondrocyte phenotype and gene expression.
Adolescent↗
HLA product expression and lymphocyte subpopulations in jejunum biopsies of children with idiopathic protracted diarrhoea and enterocyte autoantibodies.
Mature enterocytes from normal human small intestine express HLA Class II molecules, whereas the immature enterocytes of the crypts are devoid of these products. By the use of the Avidin/Biotin immunofluorescence technique, we examined HLA Class I and II expression on cryostat sections of jejunum biopsies from 10 children with idiopathic protracted diarrhoea (IPD) and circulating enterocyte autoantibodies (Ec-Abs). The results were compared with those obtained on gut specimens from nine children with protracted diarrhoea but no evidence of circulating Ec-Abs and from one child affected by gluten-sensitive enteropathy. HLA Class I expression was similar in control and pathological specimens but jejunum biopsies from children with IPD and high titres of Ec-Abs (greater than or equal to 1:64) showed 'inappropriate' Class II molecule expression in the crypt epithelial cells. This was in contrast with normal or only mildly increased Class II reactivity in the mature villi enterocytes. Conversely, jejunum biopsies from children with IPD but with low levels of Ec-Abs (less than or equal to 1:4) possessed a moderate but distinct decrease of Class II expression in mature enterocytes with a decreased number of CD3 and CD8 intraepithelial lymphocytes. It is speculated that quantitative and qualitative variations of HLA product expression in the gut epithelium of children with IPD could reflect the severity of the autoimmune process underlying the clinical picture and point to heterogeneities within the autoimmune enteropathy syndrome.
Antibodies, Monoclonal↗
A haemoprotein is not involved in the control by oxygen of enteric nitrogenase synthesis.
Strains of Escherichia coli containing the Nif+ plasmid pRD1 were used to investigate the possibility that haem proteins are involved in the regulation by O2 of nif expression. Strains lacking 5-aminolaevulinate synthase (HemA-), and hence normally unable to synthesize haem proteins, showed an identical response to O2 in the presence or absence of added aminolaevulinate (and hence of haem proteins). It was concluded that the regulatory protein NifL is not a haem protein.
Aminolevulinic Acid↗
Relief of experimentally induced pruritus with a novel eutectic mixture of local anaesthetic agents.
The effectiveness of a eutectic mixture of the local anaesthetics lignocaine and prilocaine (EMLA cream) in relieving artificially induced pruritus was examined in 20 volunteers. The study was conducted in two parts. In part one, the effect of EMLA on the threshold concentration of histamine necessary to induce pruritus was assessed by a double-blind placebo controlled method. In part two, the effect of EMLA on the perception of pruritus induced by the artificial pruritogens cowhage and papain was assessed by a single blind method. Some subjects were less sensitive to histamine after placebo cream treatment, but all subjects showed a marked reduction in sensitivity to histamine after EMLA treatment. The difference between EMLA and the placebo treatment was statistically significant. The EMLA preparation was found to be effective in alleviating pruritus induced by cowhage and papain and this effect was also statistically significant. Thus, EMLA cream was found to be effective in reducing experimentally induced pruritus and, therefore, may be useful in some clinical circumstances where persistent itch is a distressing symptom.
Adult↗
Arterial encroachment by an electrode as a cause of referred vascular headache.
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Adult↗
Interface design for indirect calorimetry in children with cerebral palsy.
The purpose of this study was to design, construct, and validate an alternative subject/instrument interface to collect metabolic data for individuals who, because of impairment, are unable to use a mouthpiece. An industrial designer directed the development of an interface design which would facilitate subject acceptance. A total of 13 subjects (eight children with cerebral palsy and five nonneurologically impaired) participated in the validation study. Metabolic data were collected at rest and during three levels of exercise, using both the traditional mouthpiece and the interface designed for this study. Exercise intensities were matched for both experimental conditions. Subjects exercised using an electrically braked ergometer configured for arm pedaling. A modification in a Beckman Metabolic Cart allowed for the collection of values with a standard mouthpiece and low-flow interface. Validity of the interface was evaluated using a concurrent, criterion procedure. Correlations of mouthpiece vs interface data during rest and across each exercise level for oxygen consumption were high (r = 0.94 to 0.84; p less than 0.05). Similar results were obtained for carbon dioxide production (r = 0.92 to 0.85; p less than 0.05).
Adolescent↗
Application of directly coupled flame atomic absorption spectrometry-fast protein liquid chromatography to the determination of protein-bound metals.
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Cadmium↗
Systemic antibiotic prophylaxis and reconstructive ear surgery.
This paper reports a multicentre, controlled, blind, prospective, randomized study into the use of prophylactic systemic antibiotics in myringoplasty surgery. Seventy-one individuals were clinically and bacteriologically assessed both preoperatively, and for a period of 8 weeks postoperatively. The results showed that antibiotic prophylaxis did not eradicate bacterial pathogens already present in preoperative ears, nor did it prevent their development during the postoperative period. The observation that an ear was wet or dry gave no indication of the actual presence or absence of pathogenic organisms.
Ampicillin↗
A girl with the Weaver syndrome.
A female with the Weaver syndrome is reported. In addition to the characteristic manifestations of overgrowth and advanced bone age, the facies were typical, with a broad forehead, hypertelorism, a long philtrum, micrognathia, and large ears. Like most other patients with Weaver syndrome, she was developmentally delayed, hypertonic, and had a hoarse voice. Other clinical features included prominent finger pads, narrow hyperconvex nails, small and narrow chest, unilateral dislocated distal ulna, and abnormal thoracic vertebrae.
Abnormalities, Multiple↗
Implication of active oxygen species as second messengers of asbestos toxicity.
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Animals↗
Ultrasound appearance of extramedullary hematopoiesis.
Extramedullary hematopoiesis accompanies a wide variety of diseases and is defined as the abnormal production of blood outside the normal confines of the bone marrow. Most of the time, extramedullary hematopoiesis is found as microscopic foci in soft tissues; however, on occasion this process may reach a size that is detectable with ultrasound. Two forms are possible: "paraosseous"--in which the normal medullary tissue of the bone marrow ruptures through the bone to present as a paraosseous soft tissue mass,--and "extraosseous"--in which extramedullary hematopoiesis occurs within soft tissue. These "masses" of hematopoietic tissue can appear almost anywhere in the abdomen and pelvis and can mimic a wide variety of more serious diseases.
Adolescent↗
myo-Inositol 1,4,5-trisphosphate mobilizes Ca2+ from isolated adipocyte endoplasmic reticulum but not from plasma membranes.
The effects of myo-inositol 1,4,5-trisphosphate (IP3) on Ca2+ uptake and release from isolated adipocyte endoplasmic reticulum and plasma membrane vesicles were investigated. Effects of IP3 were initially characterized using an endoplasmic reticulum preparation with cytosol present (S1-ER). Maximal and half-maximal effects of IP3 on Ca2+ release from S1-ER vesicles occurred at 20 microM- and 7 microM-IP3, respectively, in the presence of vanadate which prevents the re-uptake of released Ca2+ via the endoplasmic reticulum Ca2+ pump. At saturating IP3 concentrations, Ca2+ release in the presence of vanadate was 20% of the exchangeable Ca2+ pool. IP3-induced release of Ca2+ from S1-ER was dependent on extravesicular free Ca2+ concentration with maximal release occurring at 0.13 microM free Ca2+. At 20 microM-IP3 there was no effect on the initial rate of Ca2+ uptake by S1-ER. IP3 promoted Ca2+ release from isolated endoplasmic reticulum vesicles (cytosol not present) to a similar level as compared with S1-ER. Addition of cytosol to isolated endoplasmic reticulum vesicles did not affect IP3-induced Ca2+ release. The endoplasmic reticulum preparation was further fractionated into heavy and light vesicles by differential centrifugation. Interestingly, the heavy fraction, but not the light fraction, released Ca2+ when challenged with IP3. IP3 (20 microM) did not promote Ca2+ release from plasma membrane vesicles and had no effect on the (Ca2+ + Mg2+)-ATPase activity or on the initial rate of ATP-dependent Ca2+ uptake by these vesicles. These results support the concept that IP3 acts exclusively at the endoplasmic reticulum to promote Ca2+ release.
Adipose Tissue↗