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Biomedical subjects

A Zimmerman

Publications and source records attributed to A Zimmerman.

At least 19 recordsLinked to original sources

Orbital cellulitis caused by Eikenella corrodens.

Eikenella corrodens is a gram-negative, facultative anaerobic bacillus with specific culture and growth requirements and unusual antibacterial susceptibilities. It has only recently been recognized as a human pathogen. Ocular and adnexal infections with this organism are rare especially in children. We treated two children with orbital cellulitis caused by E. corrodens. One was an 8-year-old boy; the other was an 11-year-old girl. Orbital cellulitis in both patients occurred after an upper respiratory tract infection. Sinusitis and a subperiosteal abscess were present in both patients. Eikenella corrodens and Streptococcus viridans were isolated from the boy; E. corrodens was the sole isolate in the girl. Intravenous ampicillin, prolonged hospitalization, and surgical drainage of the orbit were required to control the infection in both patients. Eikenella corrodens must be considered in the differential diagnosis of orbital cellulitis in children, and ophthalmologists must become familiar with the characteristics of this peculiar organism.

Ampicillin

The paradox of adult respiratory distress syndrome in neonates.

Six full-term newborn infants are described who suffered from severe adult respiratory distress syndrome (ARDS). The triggering event was intrauterine/perinatal asphyxia in five, and group B streptococcal (GBS) septicemia in three. All had severe respiratory distress/failure and were ventilated mechanically with high concentrations of inspired oxygen and positive end-expiratory pressure. Radiography of the chest showed dense bilateral consolidation with air bronchograms and reduced lung volume. Persistent pulmonary hypertension (PPH) was documented in all cases. The coincidence of ARDS and PPH rendered respiratory management extremely difficult. For this reason high-frequency ventilation was instituted in all patients in order to improve CO2 elimination and induce respiratory alkalosis. Acute complications of respiratory therapy were encountered in five patients (pneumothorax, pulmonary interstitial emphysema, pneumopericardium). Three infants died (irreversible septic shock, progressive severe hypoxemia, and sudden cardiac arrest) after 17, 80, and 175 h of life. Histologic examination of the lungs was possible in all fatal cases and revealed typical changes of acute to subacute stages of ARDS. Three infants survived, the mean time of mechanical respiratory support being 703 h. Two patients were still dependent on oxygen after 1 month of life, and all survivors had increased interstitial markings and increased lung volumes on their chest roentgenograms at this time.

Asphyxia Neonatorum

Childhood lead poisoning: a Rhode Island perspective.

The Rhode Island Department of Health recognizes lead exposure as the State's most important environmental health problem. Historically, the program has relied on secondary prevention strategies consisting primarily of screening, case-finding, limited environmental intervention and medical management. While secondary prevention of lead toxicity identifies existing cases in a preclinical stage, it does not prevent exposure to lead hazards. The sources of lead exposure need to be appropriately identified and abated if exposures and re-exposures are to be prevented. Because of the ubiquity of lead and practical limitations of available resources, a large number of children with elevated blood lead levels will continue to go unscreened and undetected unless more effective screening strategies are implemented. Present reliance on the free erythrocyte protoporphyrin (FEP) test as a primary screening tool is recognized as an insensitive way to identify children with blood lead levels below 40 micrograms %. With growing evidence of toxicity and long term health effects associated with blood lead levels in the range between 10 and 40 micrograms %, blood lead analysis will need to become part of the routine method of screening.

Child

Primary lateral sclerosis in a child.

Primary lateral sclerosis (PLS), previously undescribed in children, is characterized by a spastic motor deterioration and pathologic demonstration of corticospinal tract degeneration. We report an infant who, before 12 months of age, developed a progressive motor disease characterized by generalized spasticity. He died at 47 months, and neuropathologic examination revealed only corticospinal tract degeneration. We conclude that this child had typical clinical and pathologic findings for PLS.

Amyotrophic Lateral Sclerosis

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

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

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

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

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

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

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

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