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Biomedical subjects

H Bertram

Publications and source records attributed to H Bertram.

48 records · Page 3Linked to original sources
PubMed1988

DNA damage and mutagenesis of lambda phage induced by gamma-rays.

Lambda phage DNA was gamma-irradiated in aqueous solution and the amount of radiation-induced strand breakage [double- and single-strand breaks and alkali-labile sites (dsb, ssb, als)] was determined. Twice as much minor structural damage (ssb and als) per lethal hit was found in this DNA compared with DNA from irradiated phage suspensions. The in vitro irradiated DNA was re-packaged into infectious particles ('pack-phage'). The induction of mutations in the cI or cII cistron was scored using SOS-induced host cells. The in vitro prepared particles were found to have second-order kinetics for mutagenesis induced by gamma-rays indicating that two pre-mutational events were necessary to produce a mutation. In contrast, bacteria-free phage suspensions ('lys-phage') showed single hit kinetics for mutagenesis after irradiation. The increase in the mutation rate in the phage particles was mainly due to minor lesions, i.e. ssb, als and unidentified base damage. In lys-phage, mutagenesis might be enhanced by clustered DNA damage--a configuration which does not exist in pack-phage. The loss of infectivity was analysed in comparison with the extent of structural damage. All lesions investigated here contributed to biological inactivation. Minor lesions were tolerated by lambda phage to a limited extent. Major lesions, such as dsb, contributed most to the loss of infectivity and can be considered as lethal events.

Bacteriophage lambda↗
PubMed1987

Differences in plasma and tissue aluminum concentrations due to different aluminum-containing drugs in patients with renal insufficiency and with normal renal function.

The gastrointestinal absorption of aluminum from orally administered aluminum-containing drugs is well documented. Retention of the absorbed aluminum leads to elevated levels of this metal in the tissue of patients with renal failure. We studied two groups of dialysis patients who had received equal amounts of the different aluminum-containing phosphate-binders Aludrox and Antiphosphat. It has recently been shown that Antiphosphat releases only a few aluminum ions in an environment of low pH. Consistent with this finding, we found the aluminum levels to be significantly higher in the plasma, bone, and hair of patients who had received Aludrox as phosphate binder. Subjects with normal renal function excreted most of the ingested and absorbed aluminum. No data are available concerning the tissue load of the element in these subjects. We studied two groups of patients with normal renal function who had received antacid drugs prior to neurosurgery on a brain tumor. The first group of patients were treated with an aluminum-rich antacid (Maalox 70); the other group received an aluminum-poor drug (magaldrate) for 10 days prior to the operation. Analysis of the brain-tissue removed revealed twofold higher aluminum levels in the patients who had received Maalox 70. These results indicate that administration of aluminum-containing drugs leads to a tissue load of aluminum in patients with an impaired renal function as well as in those with a normal function. The extent of the aluminum load depends on the aluminum content and the liberation rate of the drug.

Aluminum↗
PubMed1980

[Benzodiazepines].

Explore the source record for details and available documents.

Anti-Anxiety Agents↗
PubMedDate not supplied

[Supply of iodine during pregnancy--an inventory in Berlin, Germany].

BACKGROUND: Iodised salt was introduced in Germany in the early 1980s. A nation-wide study in 1996 showed that iodine levels among the population had improved since the introduction of the supplementation. The study did not separately investigate the iodine status of pregnant women. In our prospective study, we used three parameters to assess the iodine levels among pregnant women. PATIENTS AND METHODS: Between October 1999 and February 2000, we asked 109 German-speaking patients seeking prenatal care in our clinic to participate. Following informed consent, we measured goiter volume by ultrasound and collected venous blood (serum) and urine samples. We asked patients about any history of thyroid gland illnesses and about iodine supplementation which is generally given to pregnant patients in Germany. The blood and urine samples were stored at -18 degrees C until measurement. We used the iodine-creatinine-ratio to measure ioduria. Iodine was measured using the Cer-Arsenite-method (Dade-Behring). The thyroglobulin concentration in serum was measured using RIA. RESULTS: The mean iodine-creatinine ratio was 181 +/- 109 microg/g, 20.4 % of the patients had a ratio between 50 and 100 microg/g which is defined as iodine deficiency I degrees (WHO). 8.7 % of the patients had thyreoglobulin levels above the cut-off value of 50 ng/ml. 12.6 % of the patients had a goiter (volume > 18 ml). 58 % of the patients were taking iodine supplements. These patients had significantly higher iodine-creatinine ratio levels (204 microg/g vs. 148 microg/g, P = 0.007) and lower serum thyroglobulin levels (38.4 vs. 34.1 pmol/l, P = 0.06) than non-supplemented patients. CONCLUSIONS: The prevalence of goiter reflects an extended period of iodine deficiency. Using laboratory methods, up to 20.4 % of pregnant women were identified as having an iodine deficiency which indicates the need for a general iodine supplementation during pregnancy.

Adult↗
PubMedDate not supplied

[Menstrual toxic shock syndrome].

A 15 year old girl presented twice with severe symptoms of multiorgan disease during a period of 4 weeks resulting in intensive care necessary to control illness. According to case definition criteria, a toxic shock syndrome was diagnosed on second admission. This could be confirmed by proof of TSST-1. Beside antibiotics, no specific treatment was used and complete clinical recovery occurred with symptomatic therapy. Discussing the menstrual toxic shock syndrome we point out different aspects of the pathogenesis of the disease including the possible role of tampon use. With regard to the results of several investigators, clinical symptoms of toxic shock syndrome could be the consequence of an uncontrolled immunologic reaction. Looking at this concept, more effective therapy may be available in the near future.

Adolescent↗
PubMedDate not supplied

Supraventricular tachycardia in infants, children and adolescents: diagnosis, and pharmacological and interventional therapy.

Supraventricular tachycardia is the most frequent form of symptomatic tachydysrhythmia in children. Neonates and infants with paroxysmal supraventricular tachycardias generally present with signs of acute congestive heart failure. In school-aged children and adolescents, palpitations are the leading symptom. Chronic-permanent tachycardia results in a secondary form of dilated cardiomyopathy. Therapy for episodes of tachycardia depends on the individual situation. In severe haemodynamic compromise, or if ventricular tachycardia is suspected, tachycardia should immediately be terminated by external cardioversion during deep sedation. Vagal manoeuvres are effective in patients with atrioventricular reentrant tachycardias. Adenosine is the drug of first choice in any age group for tachycardias involving the atrioventricular node; its advantages include short half-life and minimal or absent negative inotropic effects. Adenosine may also be used in patients with wide QRS complex tachycardia. Intravenous verapamil is contraindicated in neonates and infants because of the high risk of electromechanical dissociation. In older children (>5 years) and adolescents, verapamil may be administered with the same restrictions as in adult patients (wide QRS complex tachycardia, significant haemodynamic compromise). Spontaneous cessation of tachycardia can be expected in most neonates and infants during the first year of life. Prophylactic pharmacological treatment in this age group is advisable because recognition of tachycardia is often delayed until the occurrence of symptoms. Withdrawal of drug treatment should be attempted around the end of the first year. However, in older children, spontaneous cessation of tachycardia is rare. Prophylactic drug therapy is performed on an empirical basis. Digoxin may be administered in all forms of supraventricular tachycardia in which the atrioventricular node is involved, except in patients with pre-excitation syndrome aged >1 year. In patients with atrioventricular reentrant tachycardia, class IC drugs such as flecainide and propafenone are effective. Sotalol is also effective in atrioventricular reentrant tachycardia, as well as in primary atrial tachycardia. Although amiodarone has the highest antiarrhythmic potential, it should be used with caution because of its high rate of adverse effects. In school-aged children and adolescents, radiofrequency catheter ablation of the anatomical substrate is an attractive alternative to drug therapy, with a rate of permanent cessation of the tachycardia of up to 90%. Despite the clear advantages of this procedure, it should be performed only with unquestionable indication; the long term morphological and electrophysiological sequelae on the growing atrial and ventricular myocardium are still unknown.

Adolescent↗
PubMedDate not supplied

Early and late atrial dysrhythmias after modified Fontan operation.

UNLABELLED: Occurrence of supraventricular tachycardia and sinus node dysfunction was investigated pre- and postoperatively by serial ECG and Holter monitors in 63 consecutive patients with univentricular circulation after modified Fontan operation (total cavopulmonary connection 39 patients, atriopulmonary connection 24 patients). Mean age at operation was 7.2 (0.1-20.3) years. Of the 63 patients, 14 (22%) had early (< 14 d) supraventricular tachycardia or sinus node dysfunction, which was not related to the type of operation. None of 9 patients with a preoperative mean right atrial pressure < or = 2.5 mm Hg had early supraventricular tachycardia or sinus node dysfunction in contrast to 16/54 patients (30%) with a preoperative mean right atrial pressure > 2.5 mm Hg. 6/63 patients died during the early (< 14 d) postoperative period. In only 1 child, death was related to a dysrhythmia (junctional ectopic tachycardia). During a mean follow-up of 2.5 years, 15/57 long-term survivors (21%) had late supraventricular tachycardia or sinus node dysfunction. Early supraventricular tachycardia/sinus node dysfunction was a predictor or late atrial dysrhythmias, as it occurred in 8 of the surviving 14 patients with early dysrhythmias in contrast to 4 children without early atrial dysrhythmias (p < or = 0.001). After creation of an atriopulmonary connection, 10/22 patients (45%) had late supraventricular tachycardia/sinus node dysfunction, but only 2/35 patients (6%) with a total cavopulmonary connection had late atrial dysrhythmias (p < 0.001). CONCLUSIONS: Early atrial dysrhythmias after the Fontan operation were related to preoperative hemodynamics. Early supraventricular tachycardia/sinus node dysfunction and the atriopulmonary type of Fontan connection were significant risk factors for late atrial dysrhythmias.

Child↗