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Biomedical subjects

H H Andersen

Publications and source records attributed to H H Andersen.

At least 19 recordsLinked to original sources
PubMed2004

Stopping power in insulators and metals without charge exchange.

The slowing-down process of pointlike charged particles in matter has been investigated by measuring the stopping power for antiprotons in materials of qualitatively very different nature. Whereas the velocity-proportional stopping power observed for metal-like targets such as aluminum over a wide energy range of 1-50 keV is in agreement with expectations, it is surprising that the same velocity dependence is seen for a large band-gap insulator such as LiF. The validity of these observations is supported by several measurements with protons and several checks of the target properties. The observations call for both a qualitative explanation and a quantitative theoretical model.

Journal Article↗
PubMed2002

Antiproton stopping at low energies: confirmation of velocity-proportional stopping power.

The stopping power for antiprotons in various solid targets has been measured in the low-energy range of 1-100 keV. In agreement with most models, in particular free-electron gas models, the stopping power is found to be proportional to the projectile velocity below the stopping-power maximum. Although a stopping power proportional to velocity has also been observed for protons, the interpretation of such measurements is difficult due to the presence of charge exchange processes. Hence, the present measurements constitute the first unambiguous support for a velocity-proportional stopping power due to target excitations by a pointlike projectile.

Journal Article↗
PubMed1995

Maternal HLA class II allogenotypes are markers for the predisposition to fetal losses in families of women with unexplained recurrent fetal loss.

The HLA allogenotypes DR1/Br, DR3 and DR10 (entitled risk HLA markers) have been reported as being genetic markers for the predisposition to experience unexplained recurrent fetal losses. The aim of the study was to determine whether the putative risk HLA markers might also be markers for the risk of pregnancy loss in sisters and wives of brothers of women with unexplained recurrent fetal losses. Information concerning pregnancy outcomes among the relatives of 146 consecutive women with unexplained recurrent fetal losses was collected. Ninety-five of the full sisters, 69 of the full brothers and 50 of the wives of the brothers were HLA typed. Sisters who had experienced at least one previous pregnancy loss (affected women) shared more HLA haplotypes with the proband than unaffected sisters, when the proband was positive for the risk markers (P = 0.02). More affected than unaffected sisters and brothers' wives were positive for the risk markers (P < 0.005 and P < 0.03; respectively). The lowest estimate of the odds ratio for experiencing pregnancy loss among sisters and brothers' wives who were positive compared with those negative for the risk markers was 3.5 (95% credible interval = 1.9-5.8). It is concluded that maternal DR1/Br, DR3 and DR10 allogenotypes seem to be genetic markers for the risk of pregnancy loss among relatives of women with unexplained recurrent fetal losses. The pattern of inheritance suggests a polygenic mode of inheritance with alleles linked to the risk HLA markers interacting with non-HLA linked genes expressed on the fetus or the trophoblast.

Abortion, Habitual↗
PubMed1993

[Index numbers of ambulatory care utilization. Methodical and content aspects of the value of survey data].

Index numbers of the utilization of outpatient treatment are essential for differentiated health reporting. The established doctor fulfills nodal, coordinating and regulating functions. Therefore numbers reflecting those functions are also indicators for other types of health services. They allow conclusions about motives, preferences and attitudes of the population. Based on two representative population surveys (the Socio-economic Panel and the National Health Survey of the German Cardiovascular Prevention Study) the index numbers Quarterly-Utilization, Contact-Frequency and User-Frequency are analysed. Taking the example of age and sex differences the influence of differing research designs on the validity and possibility of interpretation of the different index numbers are discussed.

Adult↗
PubMed1992

[The post-thrombotic syndrome. Description and comparison of diagnostic methods: clinical examination, venous return time, phlebography and ultrasonography].

Thirty-one patients with deep vein thrombosis (DVT) confirmed by phlebography 5-11 years previously were examined for the post-thrombotic syndrome (PTS). Where all of the patients were concerned, the examination included crossing-off of their symptoms of PTS on a special chart and clinical examination carried out by four doctors independently of one another, for 29 patients also determination of the venous return time by strain gauge pletysmography and for 29 patients also secondary phlebography (SF) and B-method ultrasonic scanning (UL). The degree of severity of PTS was determined by means of a scoring value which was calculated on the bases of four observers assessment of the clinical symptoms and findings. Significant differences were found for the clinical scores for legs with and without previous DVT, which shows that the method is of value despite a not inconsiderable interobserver variation. In the form employed here, pletysmography was found unsuitable for quantitating of PTS. In 60% of the patients, agreement was present between the clinical assessment, SF and UL. The necessity of agreement both as regards the diagnostic clinical criteria and as a measure for the degree of severity of PTS is emphasized. UL is recommended as a screening investigation for changes after DVT. Phlebography is only considered to be indicated in cases where detailed knowledge of the anatomical conditions is desired e.g. prior to venous surgery.

Adult↗
PubMed1992

The relationship between ECG signs of atrial infarction and the development of supraventricular arrhythmias in patients with acute myocardial infarction.

ECGs obtained on arrival at the hospital from 277 patients with acute myocardial infarction were analyzed retrospectively for PR displacements, which were classified as major or minor criteria for atrial infarction and related to the later occurrence of supraventricular arrhythmia in the hospital. Major criteria were (1) PR segment elevation greater than 0.5 mm in leads V5 and V6 with reciprocal PR segment depression in leads V1 and V2, (2) PR segment elevation greater than 0.5 mm in lead I with reciprocal PR segment depression in leads II and III, and (3) PR segment depression greater than 1.5 mm in precordial leads and greater than 1.2 mm in leads I, II, and III. Abnormal P waves were classified as minor criteria. Major and minor criteria were found in 15 (5.4%) and 19 (6.9%) patients, respectively. Eight (53.3%) patients with major and six (31.6%) with minor criteria had supraventricular arrhythmias, giving odds ratios of 9.9 and 3.7, respectively. Enzyme-estimated infarct size, the occurrence of heart failure, and mortality rates did not differ in patients with or without major criteria for atrial infarction. We conclude that the occurrence of PR segment displacements on the admission ECG may predict the risk of developing supraventricular arrhythmias during hospitalization for myocardial infarction.

Arrhythmias, Cardiac↗
PubMed1989

[Treatment of cardiac arrest. Recent aspects of cardiopulmonary resuscitation].

Opinions are still not unanimous about the mechanism behind circulation during external cardiac compression and this leads to uncertainty regarding the correct frequency, force of compression and its duration. Adrenaline and other alpha-stimulators increase blood flow during external cardiac compression and increase survival. Cardiac arrest results in anaerobic metabolism and combined metabolic and respiratory acidosis. On account of relatively low minute volume during external cardiac compression decrease in end-tidal carbon dioxide concentration is observed together with arterial alkalosis on account of hyperventilation and venous acidosis. No communications exist about the favourable effect of administration of bicarbonate during cardiac arrest. On the other hand, several conditions suggest that bicarbonate increases the intracellular acidosis with poorer possibilities for resuscitation with this form of treatment. Ischaemia results inter alia in intracellular accumulation of calcium which initiates potential cell destructive processes. No investigations are available which favour employment of calcium during cardiac arrest. Conversely animal experiments suggest the possibility of favourable effects from calcium-entry blockers. Ischaemia and, in particular, reperfusion release cell and vessel damaging free oxygen redicals. Intensive investigations are being conducted at present about the value of anti-oxidants for cerebral and myocardial protection.

Heart Arrest↗
PubMed1986

Didelphic uterus, atretic unilateral vagina communicating with a double vagina, ipsilateral renal hypoplasia and ectopic ureter.

A case of didelphic uterus, unilateral atretic vagina with a small communication and a right-sided hypoplastic kidney is presented and illustrated by 'fistulography' and HSG. When a communication between the atretic and the normal vagina is present, the symptoms are often vague, clinically puzzling and can easily be misinterpreted. Because of the close relationship between the development of the urinary and the female genital tract, concomitant malformations are commonly found.

Abnormalities, Multiple↗
PubMed1985

Effect of omeprazole and cimetidine on duodenal ulcer. A double-blind comparative trial.

We conducted a double-blind randomized study of 132 patients to determine whether the new, investigational proton-pump inhibitor, omeprazole (30 mg per day), would accelerate healing and pain relief, as compared with cimetidine (1 g per day), in patients with duodenal ulcer. After two weeks of treatment, which was completed by all patients, the healing rates were 73 per cent in the omeprazole group and 46 per cent in the cimetidine group (P less than 0.01). After four weeks of treatment, which was completed by 118 patients, the corresponding figures were 92 and 74 per cent (P less than 0.05). In the omeprazole group 55 per cent of the patients were free of pain after the first week, as compared with 40 per cent of those treated with cimetidine (P greater than 0.05). No major clinical or biochemical side effects of omeprazole or cimetidine were noted. A six-month follow-up study revealed no significant difference between the recurrence rates after omeprazole and after cimetidine treatment. In May 1984 clinical trials with omeprazole were temporarily suspended, since a study of long-term toxicity in rats had shown the development of gastric carcinoid tumors.

Adult↗
PubMed1982

Circadian variation of serum thyrotropin in endogenous depression.

The circadian variation of serum thyrotropin (thyroid-stimulating hormone; TSH) was studied in nine patients with endogenous depression before and after recovery. Depressed state did not appear to influence the pattern of TSH. When 2 mg of dexamethasone was administered, serum TSH was significantly reduced for 18 hours, whereafter the effect leveled off. The TSH response to thyrotropin-releasing hormone (TRH) was evaluated 25 hours after the administration of dexamethasone and the response was found to be unchanged.

Aged↗
PubMed1976

Lithium carbonate in the treatment of thyrotoxicosis. A controlled trial.

Of 24 patients with newly diagnosed thyrotoxicosis, 13 were randomly selected for treatment with methimazole 40 mg per day, and 11 for treatment with lithium carbonate in such doses that the serum lithium lay between 0-5 and 1-3 meq. per litre. The lithium treatment brought about a fall in serum-thyroxine iodine (T4I) of 27.0%, and in the free-thyroxine index (F.T.I.) of 38.1% after 10 days. A comparison of the two patient groups with regard to the fall in F.T.I. after 3 and 10 days showed no statistically significant difference; similarly the calculated confidence limits appeared to exclude any difference of clinical importance. 8 of the 11 patients subjected to lithium treatment had side-effects, so that the general condition, which was already affected by the hyperthyroidism, was worsened. It is concluded that lithium cannot be considered superior to thiocarbamides for the rapid control of thyrotoxicosis.

Clinical Trials as Topic↗