Biomedical subjects
Publications and source records attributed to H Helwig.
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Harmonisation of working conditions is one of the major aims of the European Union. The Confederation of European Specialists in Paediatrics has elaborated documents on the harmonisation of immunisations in 1987 and 1992. The new and completely updated version focuses on the variations of immunisation practices and schedules and gives criteria for minimal agreement of immunisation schedules among the member countries. Catch-up vaccinations and false contra-indications are especially stressed.
THAM (trometamol; tris-hydroxymethyl aminomethane) is a biologically inert amino alcohol of low toxicity, which buffers carbon dioxide and acids in vitro and in vivo. At 37 degrees C, the pK (the pH at which the weak conjugate acid or base in the solution is 50% ionised) of THAM is 7.8, making it a more effective buffer than bicarbonate in the physiological range of blood pH. THAM is a proton acceptor with a stoichiometric equivalence of titrating 1 proton per molecule. In vivo, THAM supplements the buffering capacity of the blood bicarbonate system, accepting a proton, generating bicarbonate and decreasing the partial pressure of carbon dioxide in arterial blood (paCO2). It rapidly distributes through the extracellular space and slowly penetrates the intracellular space, except for erythrocytes and hepatocytes, and it is excreted by the kidney in its protonated form at a rate that slightly exceeds creatinine clearance. Unlike bicarbonate, which requires an open system for carbon dioxide elimination in order to exert its buffering effect, THAM is effective in a closed or semiclosed system, and maintains its buffering power in the presence of hypothermia. THAM rapidly restores pH and acid-base regulation in acidaemia caused by carbon dioxide retention or metabolic acid accumulation, which have the potential to impair organ function. Tissue irritation and venous thrombosis at the site of administration occurs with THAM base (pH 10.4) administered through a peripheral or umbilical vein: THAM acetate 0.3 mol/L (pH 8.6) is well tolerated, does not cause tissue or venous irritation and is the only formulation available in the US. In large doses, THAM may induce respiratory depression and hypoglycaemia, which will require ventilatory assistance and glucose administration. The initial loading dose of THAM acetate 0.3 mol/L in the treatment of acidaemia may be estimated as follows: THAM (ml of 0.3 mol/L solution) = lean body-weight (kg) x base deficit (mmol/L). The maximum daily dose is 15 mmol/kg for an adult (3.5L of a 0.3 mol/L solution in a 70kg patient). When disturbances result in severe hypercapnic or metabolic acidaemia, which overwhelms the capacity of normal pH homeostatic mechanisms (pH < or = 7.20), the use of THAM within a 'therapeutic window' is an effective therapy. It may restore the pH of the internal milieu, thus permitting the homeostatic mechanisms of acid-base regulation to assume their normal function. In the treatment of respiratory failure, THAM has been used in conjunction with hypothermia and controlled hypercapnia. Other indications are diabetic or renal acidosis, salicylate or barbiturate intoxication, and increased intracranial pressure associated with cerebral trauma. THAM is also used in cardioplegic solutions, during liver transplantation and for chemolysis of renal calculi. THAM administration must follow established guidelines, along with concurrent monitoring of acid-base status (blood gas analysis), ventilation, and plasma electrolytes and glucose.
BACKGROUND: Pediatric infections still pose numerous challenges, and expert guidance is needed on many current issues including diagnostic methods and the optimal choice and duration of therapy. OBJECTIVES: To highlight areas of current concern and controversy and to provide some pointers to factors affecting the choice of antibiotic therapy. DISCUSSION: Most community-acquired pediatric infections are diagnosed on clinical grounds. Treatment is initiated on an empiric basis; microbiologic diagnosis is usual only for urinary tract infections and tonsillitis. The choice of the most appropriate antibiotic agent for ambulatory treatment depends on antimicrobial activity and pharmacokinetic parameters as well as on compliance-enhancing features such as once daily dosing, good tolerability and the acceptability of the pediatric formulation. The newer oral cephalosporins such as ceftibuten have a favorable combination of properties including excellent clinical efficacy and are increasingly being used in preference to penicillins. Although clinical cure is regarded as the "gold standard" in the evaluation of therapy, the importance of bacterial eradication must also be emphasized.
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Restrictive dermopathy is a recently described lethal congenital disorder of the skin with an autosomal recessive mode of inheritance. The rigidity of the skin impairs fetal movements in utero and causes arthrogryposis, as well as highly characteristic facial features and pulmonary hypoplasia. We report two cases of restrictive dermopathy in prematurely born infants, describe the typical pathological findings and discuss this disorder in the context of the fetal akinesia/hypokinesia deformation sequence.
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In a pilot study with a limited number of patients the efficacy and tolerance of cefixime, a new oral cephalosporin antibiotic, were investigated in 15 children with the clinical diagnosis of bacterial respiratory tract infection, otitis media or urinary tract infection. The dosage was 2 x 4 mg/kg body weight daily for a period of seven to 11 days. Clinical efficacy was good in 13 cases, and subjective tolerance was good in all cases. The results support the assumption that cefixime is suited for the treatment of children with bacterial infections of the airways and urinary tract with sensitive pathogens.
Since antiviral chemotherapy is available herpes encephalitis has become of great importance among viral affections of the central nervous system. Five young infants are presented with special problems of this disease and its diagnostic possibilities especially serological and imaging methods (CT scan, nuclear magnetic resonance tomography, ultrasonography of the brain) as well as electroencephalography. Clinical symptoms are very important since all those methods are not sufficient for early diagnosis and prompt onset of antiviral chemotherapy. Herpes encephalitis should be considered after apparent febrile seizures with focal symptoms as well as increasing disturbance of consciousness as manifestation of acute encephalopathy.
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Clinical, biochemical, functional and morphological data are presented in nine infants, children and adults, with Fanconi-Bickel syndrome. Long-term follow-up studies show severe growth retardation, partly compensated for by late onset of puberty. Glomerular filtration rate is normal or slightly decreased. Renal tubular dysfunction is characterized by a specific pattern of impaired proximal tubular transport mechanisms, with marked impairment of glucose transport. The utilization of glucose and galactose is defective, whereas fructose metabolism seems to be normal. Glycogenosis of the liver may be an epiphenomenon. Glycogen accumulation in the kidney is limited to the proximal tubule, with maximal levels in the straight part. The Fanconi-Bickel syndrome is a defined clinical entity which is distinguished from other inherited metabolic diseases by complex defects of renal tubular transport and other forms of glycogenosis.
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