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Biomedical subjects

J Weimann

Publications and source records attributed to J Weimann.

32 records · Page 2Linked to original sources
PubMed1996

[Effect of resorption of Purisole (mannitol/sorbitol solution) as a distention medium in hysteroscopic operations on cardiovascular and laboratory parameters and energy metabolism--a prospective non-randomized observational study].

This paper reports on an open explorative study on the absorption of the electrolytfree distension medium Purisole (Mannitol-Sorbitol solution) during hysteroscopic procedures and its effects on laboratory and cardiovascular parameters. Intra- and postoperative levels of mannitol and sorbitol in urine were also measured to determine elimination of both components. The study population consisted of 84 patients aged 22-62 years. 54 women underwent ablative (resection of submucous fibroids, endometrial ablation, septum resection), 30 patients non-ablative operative hysteroscopic procedures (synechiolysis, hysteroscopic proximal tubal catheterisation). The duration of operations was between 23-48 minutes. Ethanol was added to the Purisole solution for determination of resorption. In 57 cases 1% ethanol in Purisole was used as irrigating fluid. In 27 cases 2% ethanol was added to the distension fluid. A median slight encrease of central venous pressure was noted during the procedures. 18 women had an intraoperative hyponatriaemia (only 4 patients < 130 mmmol/1). For the 15 patients, in which ethanol absorption was noted, fluid resorption was calculated on the basis of blood alcohol concentration (median 850 ml). Resorption was below the determination threshold in the other 69 women. Urine examination showed intra- and postoperatively increased concentrations of sorbitol and mannitol. Fluid overload and intraoperative cardiovascular complications did not occur in our patients.

Adult↗
PubMed1996

Different effect of inhaled nitric oxide on yucatan micropig with and without congenital ventricular septal defect.

A strain of Yucatan micropigs is known to have heritable ventricular septal defects (VSDs) and thus may develop overflow pulmonary hypertension. Since inhaled nitric oxide (NO) selectively dilates pulmonary vessels, we determined its hemodynamic and co-agulatory effects in this new animal model. Eight Yucatan micropigs were anesthetized with midazolam, piritramide (a synthetic opioid) and vecuronium bromide. The presence and the size of the VSD were determined by using transesophageal color flow Doppler echocardiography. Four animals showed VSDs of 1-2 mm size. Inhaled NO was then administered with increasing inspired concentrations of 0, 5, 10, 20, 40, 80 and again 0 ppm NO for 10-min periods. NO inhalation did not affect heart rate, right cardiac output, mean arterial pressure, pulmonary arterial wedge pressure, or central venous pressure. Inhaled NO in animals with proven VSDs decreased pulmonary artery pressure (PAP) in a dose dependent manner; 5 ppm NO reduced mean PAP from 25 +/- 2.3 mm Hg to 18 +/- 0.8 mm Hg (p < 0.05), while pulmonary vascular resistance (PVR) decreased from 954 +/- 143 dyn.cm. s-5 to 661 +/- 88 dyn.cm.s-5 (p < 0.01) at the same dose. The maximum reduction in mean PAP and PVR occurred when 80 ppm NO was inhaled. Yucatan micropigs without VSDs did not respond hemodynamically to NO inhalation. Methemoglobin levels remained unchanged during the entire study. Platelet function was assessed according to the method of BREDDIN and BORN (BORN 1962). Initial aggregation and slope were affected when NO inhalation commenced. Yucatan micropigs with VSDs may represent a suitable model for further research of the in vivo effects of inhaled NO.

Administration, Inhalation↗
PubMed1994

[In vitro study of the formation of NO2 in inhalation of nitrogen monoxide].

OBJECTIVE: Nitric oxide (NO), an endogenous endothelium-derived relaxing factor, produces profound relaxation of vascular smooth muscle. Thus, inhaled NO is a potent and selective pulmonary vasodilator that may be useful for treatment of pulmonary hypertension of different aetiologies. However, the main danger of NO inhalation is spontaneous formation of toxic nitrogen dioxide (NO2) if NO is added to an oxygen-containing gas mixture. This chemical reaction depends on the time available for the oxidation and the concentration of NO and oxygen. The aim of this study was to assess in vitro the spontaneous formation of NO2 during administration of various NO concentrations with a ventilator. A modified ventilator system is described which can deliver NO within clinically relevant concentrations avoiding excessive formation of toxic NO2. METHODS: The system was evaluated using an artificial lung. NO and NO2 concentrations were measured by chemiluminescence at the proximal and distal end of the inspiratory limb. In-vitro NO2 formation was assessed during administration of 10, 20, 40, 80 ppm NO while ventilating with an FiO2 of 0.25, 0.5 and 0.75, an inspiratory minute volume of 5, 7.5 and 10 l/min (IMV) and a respiratory rate of 12/min. RESULTS: NO2 concentration correlated with increasing FiO2 and NO concentration and was inversely correlated to IMV. While ventilating with 5-40 ppm NO, an FiO2 of 0.25-0.75 and an IMV of 10 l per minute, the NO2 formation was measured to be less than 0.2 ppm and thus not clinically relevant. During administration of 80 ppm NO the NO2 formation increased to 0.3-0.6 ppm. CONCLUSION: We conclude that for patients safety concentrations less than 80 ppm of inhaled NO should be used with this ventilator system. In addition, online monitoring of the NO2 concentration in the inspiratory limb should always be performed.

Artificial Organs↗
PubMed1992

Influence of age on outcome of mechanically ventilated patients in an intensive care unit.

OBJECTIVE: To assess the influence of age on the outcome of patients receiving prolonged mechanical ventilation. DESIGN: Retrospective study. SETTING: Intensive care unit. PATIENTS: A total of 1,141 patients in our ICU during a 32-month period. A total of 536 patients required mechanical ventilation. After exclusion of 171 patients ventilated for less than 24 hrs after surgery, 365 patients were investigated. MEASUREMENTS AND MAIN RESULTS: Two hundred sixty-six (73%) patients were aged less than 70 yrs; 99 (27%) patients were greater than or equal to 70 yrs. There was no significant difference in mortality rate between the younger and the older age groups. There was no significant influence of other important factors, such as severity of illness, duration of mechanical ventilation, or length of ICU stay. The only factor showing a significant influence on patient outcome was the reason for mechanical ventilation. There were more survivors in the group being ventilated because of ventilatory insufficiency than in the group with oxygenation impairment (57.8% vs. 23.9%, p less than .001). CONCLUSION: An influence of age on the outcome of mechanically ventilated patients in the ICU could not be ascertained in this study.

Adolescent↗
PubMed1978

[Thymomas (author's transl)].

Immunological investigations concerning pathological autoantibodies and defects of humoral immunity were performed in 7 patients with thymomas, 5 of which showed invasive growth. The number of B and T lymphocytes in blood was determined at the same time using membrane markers as well as blood lymphocyte stimulation with phytohaemagglutinine. Two of the 3 patients with auto-antibodies against striated muscles or nuclei showed the clinical signs of accompanying disease (myasthenia gravis, lupus erythematodes). A humoral immunodisturbance with IgM deficiency was demonstrable in one patient and was accompanied by clinical symptoms. Lymphopenia with decreased numbers and functional disturbance of T and B lymphocytes could be shown in the majority of patients. Immunological investigations simplify proof of accompanying diseases in thymomas. These represent an important prognostic criterium in the same way as does invasive growth.

Adult↗
PubMed1977

Crosslinked insulins: preparation, properties, and application.

Crosslinked insulins have proved to be valuable for structure-function studies and as proinsulin models. In the first part of the paper, a short review of the literature on analytical investigations, the preparation of A1-B1- and A1-B29-crosslinked derivatives, their biological activities in vivo and in vitro, and CD-spectral properties is given. The results of reduction/reoxidation studies with insulin derivatives containing irreversible and cleavable crosslinks are summarized. In the second part, new A1-B29-crosslinked monomers and 3 symmetrical dimers, linked between A1-A'1, B1-B'1 and B29-B'29, are described, as well as some results of tritium-labelling and of enzymatic degradation experiments with A1-B29-linked insulins.

Amino Acid Sequence↗