Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intense cyanosis in a previously well, 30-month-old, white girl was found to be due to the ingestion of benzocaine. A wide variety of chemical compounds present in many proprietary products, when ingested, can cause this presentation in individuals with structurally normal hemoglobin and normal activity of methemoglobin reductase. The phenomenon appears to be dose-related. Immediate recognition and initiation of appropriate therapy will effect a rapid reversal of the methemoglobinemia, and in some cases, may be life-saving. Caution should be exercised in the use of benzocaine-containing preparations.
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PMID:Benzocaine-induced methemoglobinemia. 53 64

It has been analised cases of toxic methemoglobinemia in newborns and sucklings on patients of children department city hospital Sombor in period from 1968 to 1979. In all patients methemoglobinemia was caused with wellwater containing nitrates. Originate of this state depends on: growth of child because in first few month of life they have immature methemoglobin reductase in erythrocyte, hypovitaminosis C and gastrointestinal disfunction. Diagnosis was based on anamnestical data that was used water from unhygenic well, on cyanosis of various intensity and that have disappeared during the treatment with vitamin C and not give any recurrence later. In last years number of such cases is decreasing because of better suply with proper drinking water. Further decrease can be achieved with health education and prophylactic peroral consumption of vitamin C in predisposing regions.
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PMID:[Toxic methemoglobinemia in newborns and infants]. 55 47

The administration of "sweet spirits of nitre" (4% ethyl nitrite CH3CH2ONO in 70% ethyl alcohol) was followed by acute methemoglobinemia and severe anoxic metabolic acidosis in infant twins, Methylene blue administration reversed methemoglobinemia in both, but one twin died from the consequences of hypoxemia. Hemoglobin electrophoresis and methemoglobin reductase determinations were normal for age. This medicine is available without prescription and contains the potent oxidant ethyl nitrite. In infants with sudded death or onset of cyanosis, appropriate toxicological and historical information should be obtained.
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PMID:Sudden death in an infant from methemoglobinemia after administration of "sweet spirits of nitre". 83 12

Report on a further hemoglobin M variant, discovered in a boy with congenital cyanosis. Chemical analysis of hemoglobin structure revealed indentity with HbM Saskatoon (= beta63 His leads to Tyr). The abnormal hemoglobin is characterized by normal oxygen transport function. The observed slight constant hemolysis is thought to be due to increased instability of the abnormal hemoglobin molecule. In addition to the hemoglobin anomaly, the activity of NADH-methemoglobin reductase was reduced by approximately 40% of normal. None of the parents presented with an abnormal hemoglobin, indicating that the occurrence of hemoglobin M Erlangen is most likely the result of a new mutation.
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PMID:[HbM Erlangen: alpha2beta263(e7) tyr. New mutation with haemolysis and NADH-methaemoglobin reductase deficiency (author's transl)]. 116 74

Acquired methemoglobinemia results from the exposure to various chemicals and drugs able to oxidize hemoglobin at a rate exceeding the normal enzymatic capacity for hemoglobin reduction. Levels of methemoglobin exceeding 60-70% may be associated with coma and death. We describe a case of complete, uneventful recovery involving a 10 week-old infant who presented to the Emergency Department with profound sudden onset of cyanosis, irritability, metabolic acidosis, and a lethal methemoglobin level of 71.4%. Intravenous administration of 12 mg methylene blue resulted in immediate resolution of the cyanosis and reduction of measured methemoglobin to 1.3%. The carboxyhemoglobin was negative. Sodium bicarbonate successfully corrected the acidosis. RBC reductase measurement was within normal limits, ruling out congenital methemoglobinemia. Family history revealed a wood-burning stove which emitted pine tar fumes as the potential environmental methemoglobin-producing source. The infant's cradle was situated five feet from the stove. The infant was discharged on day three of hospitalization with a methemoglobin level of 0.2%.
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PMID:Environmentally-induced methemoglobinemia in an infant. 154 42

During investigation of chronic cyanosis in a 25 year old male, after excluding pulmonary and cardiac causes, methemoglobinemia was suspected. Investigation of the activity of methemoglobin reductase clenched the diagnosis of homozygous cytochrome b5 reductase deficiency in a case of recessive congenital methemoglobin type I (absence of neurologic symptoms).
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PMID:Congenital cyanosis due to methemoglobin reductase deficiency: first reported Tunisian case. 258 7

A case of cyanosis during general anaesthesia in a patient suffering from congenital deficiency of metahaemoglobin-reductase (diaphorase) is reported. The anaesthesiological technique and the probable triggering cause are analysed. The investigation carried out in members of the family to obtain confirmation of the genetic origin of the enzymatic deficiency is also reported.
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PMID:[Congenital deficiency of metahemoglobin-reductases (diaphorases). A case of cyanosis during general anesthesia]. 277 13

Two cases of the congenital methemoglobinemia in children due to the deficiency of NADH-dependent methemoglobin reductase in erythrocytes. These children were referred to the Cardiological Ward at the Child Health Centre with suspected cyanotic heart defect. Cardiological examinations excluded heart defect but an increased blood methemoglobin level and decreased activity of NADH-dependent methemoglobin reductase were found, that caused methemoglobinemia. Methylene blue and vitamin C diminished cyanosis. These cases advocate inclusion of methemoglobinemia into differential diagnosis of cyanotic disorders especially if there is no evident pathology in cardio-vascular system.
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PMID:[Cyanosis in children caused by inherited methemoglobinemia due to deficiency of NADH-dependent methemoglobin reductase in erythrocytes]. 281 7

The case of a 3-week-old male infant is described. After receiving an iatrogenic overdose of metoclopramide (1.0 mg/kg every six hours) throughout a 36-hour period for the treatment of suspected gastroesophageal reflux, he became cyanotic, lethargic, and irritable, he fed poorly, and he had diarrhea and respiratory distress. Methemoglobinemia (20.5%) and reduced oxyhemoglobin saturation (79%) were identified. The patient had an excellent clinical response following a single IV dose of methylene blue. Subsequently, methemoglobin reductase activity was normal and there was no measurable hemoglobin M. The diagnosis of methemoglobinemia should be considered in any infant receiving large doses of metoclopramide who has clinical findings of cyanosis, ashen color, or a history of lethargy and/or motor restlessness.
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PMID:Metoclopramide-induced methemoglobinemia. 340 65

Methaemoglobin is haemoglobin with the iron oxidised to the ferric (Fe ) state from the normal (or reduced) ferrous (Fe++) state. Methaemoglobinaemia refers to the presence of greater than the normal physiological concentration of 1 to 2% methaemoglobin in erythrocytes. Methaemoglobin is incapable of transporting oxygen. It has an intense dark blue colour; thus, clinical cyanosis becomes apparent at a concentration of about 15%. The symptoms are manifestations of hypoxaemia with increasing concentrations of methaemoglobin. Concentrations in excess of 70% are rare, but are associated with a high incidence of mortality. Methaemoglobinaemia may be congenital but is most often acquired. Congenital methaemoglobinaemia is of two types. The first is haemoglobin M disease (several variants) which is due to the presence of amino acid substitutions in either the alpha or beta chains. The second type is due to a deficiency of the NADH-dependent methaemoglobin reductase enzyme. This deficiency has an autosomal dominant transmission, and both homozygous and heterozygous forms have been reported. The heterozygous form is not normally associated with clinical cyanosis, but such individuals are more susceptible to form methaemoglobin when exposed to inducing agents. A wide variety of chemicals including several drugs, e.g. the antimalarials chloroquine and primaquine, local anaesthetics such as lignocaine, benzocaine and prilocaine, glyceryl trinitrate, sulphonamides and phenacetin, have been reported to induce methaemoglobinaemia. An intense 'chocolate brown' coloured blood and central cyanosis unresponsive to the administration of 100% oxygen suggests the diagnosis. A simple bedside test using a drop of the patient's blood on filter paper helps to confirm the clinical suspicion. Methaemoglobin can be quantitated rapidly by a spectrophotometric method.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Drug- and chemical-induced methaemoglobinaemia. Clinical features and management. 353 20


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