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Biomedical subjects

A Zimmerman

Publications and source records attributed to A Zimmerman.

At least 37 records · Page 2Linked to original sources
PubMed1988

Ferritin: an expanded role in metabolic regulation.

Synthesis of ferritin, a constitutive protein, is increased by iron. This protein is well recognized as a protein which detoxifies, stores and transports iron. The 24 subunits of ferritin assemble to form a protomer of Mr 480,000. This protein shell can sequester up to 4500 g atoms of iron as ferrichydroxyphosphate. Ferritin in vitro and in vivo binds other metal ions such as Cu, Zn, Cd, Pb, Be and Al. Next to Fe it binds large quantities of Be. Therefore, in vitro ferritin protects against and reverses the inhibition by Be of enzymes susceptible to this metal ion. Also, rats pretreated with Fe survive otherwise toxic levels of either pulmonary or intravenous exposure of Be. Liver ferritin from rats injected with Zn contains some of the injected metal ion. Incubation of such ferritin-zinc complex with zinc-requiring apoenzymes restores their activity. Fe(III) of ferritin is released only after its reduction to Fe(II) by a reductant. Incubation of phosphoglucomutase, a phosphoserine containing enzyme with ferritin and a reductant causes irreversible inactivation of the enzyme and removes 70% of its phosphate. Some other phosphoproteins are similarly inactivated but without the loss of the bound phosphate. Thus, uncontrolled release of iron from ferritin, in the presence of a reductant and oxygen can modify several biomolecules and can affect metabolic processes. A subclass of ferritin, acidic isoferritins, have been implicated in leukemia-associated inhibitory activity and has been suggested to inhibit production of Ia+ macrophage progenitors.

Animals↗
PubMed1987

Urinary calculi in association with glomerular immaturity.

The syndrome of glomerular immaturity associated with renal tubular acidosis and nephrocalcinosis or urolithiasis is illustrated by a case in which the diagnosis was made before the histological confirmation. Cases of urolithiasis in infants may be associated with this syndrome and attention must be paid to this rare but severe condition.

Acidosis, Renal Tubular↗
PubMed1984

Clustering of human H1 and core histone genes.

An H1 histone gene was isolated from a 15-kilobase human DNA genomic sequence. The presence of H2A, H2B, H3, and H4 genes in this same 15-kilobase fragment indicates that mammalian core and H1 histone genes are clustered.

Animals↗
PubMed1984

Cell cycle regulation of human histone H1 mRNA.

A cloned genomic DNA fragment containing a human histone H1 gene has been used to analyze histone H1 gene expression in two human cell lines (HeLa S3 and WI-38). The cellular abundance of histone H1 mRNA was compared with that of core (H2A, H2B, H3, and H4) histone mRNAs as a function of the cell cycle: core and H1 histone mRNA levels are related both to each other and to the apparent rate of DNA synthesis and are rapidly destabilized after DNA synthesis inhibition. The use of three synchronization protocols, and of transformed and normal diploid cells in culture, suggests that the detected core and H1 histone mRNA levels are regulated by similar mechanisms in continuously dividing human cell lines and nondividing cells stimulated to proliferate.

Cell Cycle↗
PubMed1984

Klinokinesis in polymorphonuclear leucocytes.

Klinokinesis has previously been demonstrated in bacteria and amoeba but not in metazoan cells. We report here evidence for klinokinesis in leucocytes. Changes in the rate of human and rabbit polymorphonuclear leucocyte (PMN) displacement elicited by uniform concentrations of the chemotactic peptide formyl-Met-Leu-Phe (fMLP) were associated with alterations of the klinolocomotion index (KI), the mean angle of turns greater than or equal to 90 degrees and the frequency of changes in direction greater than or equal to 90 degrees. Orthokinesis and klinokinesis had synergistic effects and both elements of chemokinesis may have a substantial influence on PMN velocity. The relationship between speed and changes in the direction of locomotion has been analyzed and the putative role of klinokinesis in chemotactic responses is discussed.

Animals↗
PubMed1982

Prognostic value of the electroencephalogram in neonatal asphyxia.

In order to determine whether an EEG early in the course of asphyxia neonatorum is of any more value than the neurological examination in predicting outcome we reviewed case histories of 38 infants with asphyxia neonatorum. The EEG background activity was valuable in predicting outcome. Normal and maturationally delayed EEGs were associated with normal outcomes while low voltage, electrocerebral inactivity and burst suppression EEGs were highly correlated with severe neurological sequelae. Epileptiform activity was not as predictive of outcome as background activity. Although initial normal neurological examinations were associated with normal developmental and neurological outcomes, moderately and severely abnormal infants had more variable courses. A single EEG done early in the course of asphyxia neonatorum is a more sensitive predictor of outcome than the neurological examination.

Asphyxia Neonatorum↗
PubMed1982

Galactose intolerance in individuals with double heterozygosity for Duarte variant and galactosemia.

The most frequent cause for an abnormal result during screening of newborn infants for galactosemia is double heterozygosity for Duarte variant and galactosemia, in which galactose-1-phosphate uridyl transferase activity is reduced to approximately 17% of normal. Thirty-nine oral galactose tolerance tests were performed in 27 infants and children with this condition. In comparison to age-matched controls, all children with this genetic variant reached much higher levels of blood galactose and galactose-1-phosphate following oral galactose challenge. The integrated plasma galactose response increased with the age of the child, whereas integrated erythrocyte galactose-1-phosphate responses were elevated to the same degree at all ages. Although all children appeared clinically normal, the marked abnormalities in the ability to dispose of ingested galactose raise questions concerning appropriate dietary recommendations for such children.

Blood Glucose↗
PubMed1982

Venous stasis retinopathy associated with embolic obstruction of the central retinal artery.

A case of venous stasis retinopathy in a 58-year-old male is reported. Despite carotid endarterectomy for ipsilateral internal carotid atheromatous disease, the retinopathy persisted until the embolic obstruction of the central retinal artery resolved spontaneously. Then the venous stasis retinopathy was relieved. In patients with venous stasis retinopathy and reduced arterial pressure that cannot be attributed to carotid disease, an occult but hemodynamically significant arterial obstruction posterior to or at the lamina cribrosa may be suggested.

Embolism↗
PubMed1981

Diameter of the cell-to-cell junctional membrane channels as probed with neutral molecules.

The cell-to-cell channels in the junctions of an insect salivary gland and of insect and mammalian cells in culture were probed with fluorescent molecules-neutral linear oligosaccharides, neutral branched glycopeptides, and charged linear peptides. From the molecular dimensions of the largest permeants and smallest impermeants the permeation-limiting channel diameter was obtained: 16 to 20 angstroms for the mammalian cells and 20 to 30 angstroms for the insect cells.

Animals↗
PubMed1981

Are axonally transported proteins released from sciatic nerves?

A recent report by Hines and Garwood claimed a significant release of axonally transported proteins from frog sciatic nerve into a surrounding solution. In the present study no significant release of axonally transported protein from frog sciatic nerves was detected with more stringent control for non-axonal sources of released protein.

Animals↗
PubMed1980

Staff attitudes and treatment effectiveness.

Previous studies of the impact of staff attitude on outcome among psychiatric hospital patients appear to have yielded conflicting results. These conflicts could be the result of the somewhat imprecise methods generally used in such research. In the present study, the correlations between the mean OMISOS attitude scale scores of those staff members who had the greatest impact on patients and the improvement shown by those patients on six personality scales and two measures of tremulousness during the first 2 weeks of hospitalization were evaluated. Protective Benevolence, a scale that reflects a friendly, laissez-faire approach, was associated with improvement. However, the variables reflected by the Authoritarianism, Accountability and Conventionality scales appeared to impede progress. The relationships between staff attitude and improvement were, in any event, small.

Adult↗