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Biomedical subjects

H Berg

Publications and source records attributed to H Berg.

At least 55 records · Page 3Linked to original sources
PubMed1993

Breathing volumes and gas exchange during simulated rapid free ascent from 100 msw.

The crew of a disabled submarine can be rescued by means of free ascent through the water to the surface. Pulmonary gas exchange was studied during simulated rapid free ascent in subjects standing immersed to the neck in a pressure chamber. The pressure was rapidly increased to 1.1 MPa [100 meters seawater (msw)] followed by decompression at 0.03 MPa/s (3 msw/s). Effective inspired tidal volume, as estimated by an Ar dilution method, fell gradually to zero during decompression from 20 to 0 msw. Directly determined expired tidal volumes were increased up to two to three times at the time of return to surface pressure compared with pre- and postdecompression volumes. End-tidal PCO2 was increased on compression and fell to a nadir of 3.4 kPa (25 Torr) at the time of return to surface pressure. Thus, intrapulmonary gas expansion caused simultaneous inspiratory hypoventilation and expiratory hyperventilation. If O2-enriched gas is to be used to reduce the risk of decompression sickness, it should be administered early during decompression to alter the intrapulmonary gas composition. The time course of arterial PCO2 changes as reflected by end-tidal values during short-lasting compression/decompression would act to promote inert gas supersaturation in the brain.

Adult↗
PubMed1992

Delta-electron emission in fast heavy ion atom collisions.

Biological damages such as mutations, chromosomal aberrations etc. are a consequence of biochemical changes mostly in the DNA. With ionizing radiation, these chemical changes are due to primary ionization events and secondary ionization effects caused by the primarily produced electrons. Differences in the biological response of densely ionizing radiation, like heavy charged particles, in comparison to sparsely ionizing radiation, such as X- or gamma-rays, are mainly due to the differences in the production of the so called delta-electrons. Therefore, the emission process of electrons i.e. the cross section for the primary ionization event as well as the energy and angular distribution of the emitted electrons should be understood in detail. The delta-electron emission processes occuring in fast heavy ion atom collisions are explained qualitatively. The different spectral structures of electron emission arising from either the target or the projectile are explained in terms of simple models of the kinetics of momentum transfer induced by the COULOMB forces. In collisions of very heavy ions with matter, high nuclear COULOMB forces are created. These forces lead to a strong polarization of the electronic states of the participated electrons. The effects of this polarization are discussed.

Argon↗
PubMed1992

[Critical retrospective evaluation of the treatment of 400 patients with laryngeal cancer].

This retrospective study deals with the outcome of 401 patients with laryngeal carcinoma who were treated between 1975 and 1986 either by operation alone or by operation and irradiation. The patients as a group, the concepts of treatment, and the course of disease as found retrospectively are described. T and N categories are compared with the respective pT and pN categories: T and pT categories corresponded in 83.3% of the cases while there was only a 67.4% correspondence between each N and pN category. The survival rates using the Kaplan-Meier estimation according to the localization and extension of laryngeal tumor, pN category and method of resection are discussed in detail.

Adult↗
PubMed1991

Hypoxaemia during anaesthesia--an observer study.

We have investigated 296 inpatients in a single-blind observer study to determine the incidence, degree and duration of hypoxaemia during anaesthesia. The clinical recognition of hypoxaemia, period of time until recognition and risk factors were studied. Oxygen saturation (Spo2) was monitored continuously with a pulse oximeter (Ohmeda, model 3700). One or more episodes of mild hypoxaemia (Spo2 86-90%) were recorded in 53% of patients. Severe hypoxaemia with Spo2 values less than 81% were recorded in 20% of patients. The mild hypoxaemic episodes lasted up to 34.6 min (mean 2.3 min) and 70% were not detected by the anaesthetist. In the remaining 30% of episodes, the anaesthetist diagnosed the complication with a mean time delay of 70 s. After intervention a mean time delay of 57 s was recorded until Spo2 exceeded 90%. Utilizing a stepwise multiple logistic regression analysis, we found that risk factors associated with a greater incidence of hypoxaemia were patient age (P less than 0.005) and anaesthetic technique (P less than 0.00001). We conclude that hypoxaemic episodes in our operating rooms are common during anaesthesia and suggest preoxygenation in all patients in addition to administration of supplementary oxygen during arousal from anaesthesia and during transfer to the recovery room.

Adolescent↗
PubMed1991

Thyroid function tests in patients with acquired immune deficiency syndrome and healthy HIV1-positive out-patients.

The thyroid function tests as well as evidence of thyroiditis were studied in 18 male patients with acquired immune deficiency syndrome (AIDS) and 12 healthy HIV1-positive persons compared with an age-matched control group. Serum total thyroxine was not significantly different between the groups, but both serum total triiodothyronine, triiodothyronine uptake test, and free thyroid hormone indices showed significantly decreasing values from HIV1-positive healthy persons to AIDS patients compared with controls (P value from less than 0.05 to less 0.001). Serum TBG was elevated in HIV1-positive subjects and in patients with AIDS, with a significant inverse correlation with the T3-uptake test (Spearman's rho = 0.657, P less than 0.01). There was no correlation between thyroxine binding globulin and the other measured variables. The serum level of thyrotropine was not significantly different in the groups, whereas serum thyroglobulin was significantly lowered in the AIDS group. There was no correlation between thyroid function variables and survival time, hepatic function and ratio of T-helper to T-suppressor cells. No evidence of thyroiditis was observed. In conclusion thyroid tests showed an atypical outcome in HIV1-positive patients with or without AIDS compared with the pattern normally seen in non-thyroid illness, and should, therefore, caution the interpretation of the biochemical changes when diagnosing abnormal thyroid function in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Effectiveness and tolerance of long-term uricosuric treatment].

In an open-controlled, randomized trial over 24 weeks, the serum uric acid lowering effect of a daily dose of 100 mg allopurinol in combination with 20 mg benzbromarone compared to 300 mg allopurinol only was investigated on a total of 60 patients suffering from hyperuricemia. Both preparations led to a decrease of the serum uric acid value to normal. In those patients however, who had received the combination the reduction of the serum uric acid level was more pronounced. Tolerance was generally good. Side-effects were not reported.

Adult↗
PubMed1989

Bending of oligonucleotides containing an isosteric nucleobase: 7-deaza-2'-deoxyadenosine replacing dA within d(A)6 tracts.

Decanucleotide duplexes of the parent sequence d(GGCA6C).d(CCGT6G) containing various numbers of 2'-deoxytubercidin (c7Ad) in place of 2'-deoxyadenosine have been synthesized. Phosphoramidites of protected c7Ad (3a,b) were used in automated solid-phase synthesis together with those of regular nucleosides. Upon enzymic 5'-phosphorylation and ligation, multimers of 5 and 7-11 were analyzed by polyacrylamide gel electrophoresis and compared with regard to intrinsic, sequence-directed bending. Replacement of dA by c7Ad within the oligomers decreased bending, but the extent depends strongly on the position of incorporation: strong bending was still observed if the 3'- and 5'-terminal dA residues of the dA tract were replaced while the interruption of the d(A)6 tract by c7Ad reduced bending strongly.

Aminoglycosides↗
PubMed1989

[Oxygen status of arterial blood including uncompensated mixed venous oxygen tension and cardial oxygen compensation factor. Reevaluation on the basis of 250 arterial punctures].

In arterial blood from 250 patients we measured pH, pco2, and po2 (electrochemically) together with total-hemoglobin concentration, oxygen saturation, carboxy- and methemoglobin fractions (spectrometrically). With a previously published algorithm we calculated the effective hemoglobin concentration, total-oxygen concentration, half saturation tension, erythrocyte 2,3-diphosphoglycerate concentration, and two new oxygen parameters: uncompensated mixed venous oxygen tension and cardiac oxygen compensation factor. 11% of the patients have normal arterial oxygen tension, but nevertheless risk of tissue hypoxia judged from the two new oxygen parameters. This is due to a low hemoglobin concentration and/or low half saturation tension (increased hemoglobin oxygen affinity). Some patients have decreased arterial oxygen tension but normal uncompensated mixed venous oxygen tension (15%) or normal cardiac oxygen compensation factor (9%). This is due to a high hemoglobin concentration and/or increased half saturation tension. The latter varies from 2.6 to 5.2 kPa (ref.: 3.3-3.9 kPa); 36% have decreased, 27% increased values. The 2,3-diphospho-glycerate concentration varies from 2.0 to 7.9 mmol/l (ref.: 3.6-5.1 mmol/l); 14% have decreased, 30% increased values. Uncompensated mixed venous oxygen tension varies from 1.8 to 5.7 kPa (ref.: 4.5-5.5 kPaf). The cardiac oxygen compensation factor varies from 0.9 to infinity (ref.: 0.8-1.6). We conclude that the variation in the different oxygen parameters is so significant that it justifies routine calculation for all arterial blood samples where the measurement on a conventional blood gas analyzer is supplemented with measurement on one of the new multi-wavelength hemoximeters. The calculation algorithm permits calculation of all the oxygen parameters for the majority of arterial samples (84%) where the oxygen saturation is less than or equal to 0.970.

Adult↗
PubMed1989

[Fibrinolytic treatment of superior vena cava syndrome, a complication of a central venous catheter].

Central venous catheterization plays a major role in anesthesia and intensive care medicine. Catheter-induced thrombosis, a common complication, develops in 15-47% of cases. A possible sequela is the occlusion of a large central vein; one early sign is edema of the upper extremities or face. Although complete occlusion of a central vein appears to be rare, this complication should be recognized in view of the extensive use of central venous catheters today. We report a case of severe superior vena cava syndrome that developed after catheterization of the right internal jugular vein. Fibrinolytic treatment using streptokinase and urokinase proved to be successful. A dose of 100,000 units/h was chosen for each agent, and heparin was added during urokinase therapy. Profound clinical improvement was observed after a few hours. Bleeding complications did not occur during the 4 days of treatment.

Catheterization, Central Venous↗
PubMed1984

Persistently increased intestinal fraction of alkaline phosphatase.

Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not apparent during hospitalization. His blood type was O, RH+, Le (a-, b+) and he was a secretor of H-substance, which may be associated with rising API activity after fat-loading. In this case API was unchanged after fat-loading. Neither intestinal nor liver diseases were found, and no other cause for the elevated phosphatase activity could be demonstrated.

Alkaline Phosphatase↗
PubMed1984

[Electrochemical reduction of the anthracycline antibiotic 5-iminodaunorubicin. Isolation and structural clarification of the reduction products].

After electrochemical reduction of the potential cancer chemotherapeutic 5-iminodaunorubicine two new compounds, were isolated purely by chromatographic separation. Based on 1H-NMR, IR-, UV/VIS- and MS-investigations the one reaction product was identified as 7-desoxy-5-iminodaunorubicinone as expected, while the other was proofed as 9-acetyl-9,12-dihydroxy-4-methoxy-7,8,9,10-tetrahydroxy-6,11-naphthac enchinone.

Daunorubicin↗