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Biomedical subjects

S Martens

Publications and source records attributed to S Martens.

At least 37 records · Page 2Linked to original sources
PubMed2001

Conventional carbon dioxide application does not reduce cerebral or myocardial damage in open heart surgery.

BACKGROUND: Open heart surgery is associated with a significant risk of cerebral and myocardial dysfunction, which is attributed in part to air embolism from incompletely deaired cardiac chambers. To evaluate the impact of carbon dioxide (CO2) insufflation to the thoracic cavity, a prospective randomized study was designed. METHODS: A total of 62 elective patients were randomly assigned to CO2 insufflation (group I, n = 31) or control (group II, n = 31). According to the Parsonnet risk score, 16 patients in group I (52%) and 10 patients in group II (32%) were categorized as being at either high risk or extremely high risk. RESULTS: In group II, perioperative mortality was 16.1% (5 patients); in group I, 1 patient died (ns). Creatine kinase MB isoenzyme, as a marker of myocardial damage, was more elevated in group I after surgery (38.0 +/- 4.1 vs 28.0 +/- 2.1, p = 0.02). Neurocognitive test scores did not reveal significant postoperative differences between groups. CONCLUSIONS: Although mortality was lower with CO2 insufflation, no benefit could be demonstrated for markers of cardiac ischemic damage or neurocognitive outcome in this high-risk population. As CO2 concentrations in the thoracic cavity did not necessarily reach anticipated levels, our method of application is in question.

Aged↗
PubMed2001

Cloning of parsley flavone synthase I.

A cDNA encoding flavone synthase I was amplified by RT-PCR from leaflets of Petroselinum crispum cv. Italian Giant seedlings and functionally expressed in yeast cells. The identity of the recombinant, 2-oxoglutarate-dependent enzyme was verified in assays converting (2S)-naringenin to apigenin.

Apigenin↗
PubMed2001

Metabolic engineering and applications of flavonoids.

During the past decade, the increasing knowledge of flavonoid biosynthesis and the important function of flavonoid compounds in plants and in human and animal nutrition have made the biosynthetic pathways to flavonoids and isoflavonoids excellent targets for metabolic engineering. Recent strategies have included introducing novel structural or regulatory genes, and the antisense or sense suppression of genes in these pathways.

Flavonoids↗
PubMed2001

Long term follow up of left ventricular function after repair of left ventricular aneurysm. A comparison of linear closure versus patch plasty.

OBJECTIVE: Suboptimal early and unsatisfactory late results after linear closure of left ventricular aneurysms, have focused attention on more physiologic concepts of aneurysmectomy, like endoventricular patch plasty. The aim of our study was to compare clinical results of linear closure and patch plasty 8 years after surgery. METHODS: From a total of 102 patients with postinfarctional left ventricular aneurysms, clinical outcomes and echocardiographic measurements of left ventricular function in 32 patients who underwent linear closure were compared to those of 20 patients who had endoventricular patch plasty. RESULTS: The two groups were matched with respect to age, gender, comorbid risk factors, functional class, urgency of the operation and concomitant procedures. In the patch plasty group, ejection fraction increased from 33.1+/-12.2% to 34.4+/-9.7%. In the linear closure group, ejection fraction decreased from 44.3+/-10.9% to 40.1+/-7.9%. Perioperative mortality and complications, long term survival and functional class were similar in both groups with a total perioperative mortality of 1.9%, an 8-year survival rate of 85.6%, and a mean NYHA functional class of 2.51. CONCLUSION: Long-term follow up showed a decline in ejection fraction in the direct closure group and a slight increase in the patch plasty group. We suggest that linear closure should be limited to small ventricular aneurysms and that large ventricular aneurysms extending into the septum should be treated by patch plasty.

Aged↗
PubMed2001

Heparin coating of the extracorporeal circuit combined with leukocyte filtration reduces coagulation activity, blood loss and blood product substitution.

BACKGROUND: Cardiopulmonary bypass is associated with activation of the coagulation cascade. Occasionally, this results in postoperative hemorrhage and consequently the need for blood products associated with increasing costs and risk of infection. Contact activation of the intrinsic coagulation pathway, and damage to cellular blood components with the release of proteolytic substances from neutrophil granulocytes have been linked to these coagulation disorders. METHODS: Eighteen routine CABG-patients were randomly assigned to totally heparin coated circuits (Bioline coating) combined with leukocyte filtration in a double blind protocol (group I), 34 patients served as controls (group II). Leukocyte filters were activated before release of the aortic crossclamp. Coagulation activity, postoperative blood loss, and substitution with blood products were assessed. RESULTS: Blood loss in the first 24h after surgery was significantly lower with combined application of heparin coating and leukocyte filters (group I) vs. controls (group II) (526+/-78 ml vs. 786+/-88 ml; p<0.05). Thrombin formation represented by prothrombin fragments 1+2 was significantly lower in group I vs. group II after declamping of the aorta (2.1+/-0. 3 nmol/L vs. 4.0+/-0.3 nmol/L; p<0. 05). Group I showed higher AT II plasma than group II (48.8+/-3.2% vs. 41.5+/-1.77%; p<0.05). CONCLUSIONS: Leukocyte filtration during reperfusion in heparin coated cardiopulmonary bypass circuits is associated with lower coagulation activation, decreased blood loss and reduced transfusion of packed red cells in elective CABG patients.

Aged↗
PubMed2000

Identification of the Arabidopsis thaliana flavonoid 3'-hydroxylase gene and functional expression of the encoded P450 enzyme.

The phenylpropanoid pathway results in the synthesis of thousands of compounds, including flavonoids like flavonols, anthocyanidins and tannins. In Arabidopsis thaliana, the lack of tannins in the seed coat (testa) causes the transparent testa (tt) phenotype. In the present study, we identified the gene responsible for the tt7 mutation. We show that TT7 encodes the enzyme flavonoid 3'-hydroxylase (F3'H), and demonstrate that this P450-dependent monooxygenase has F3'H activity. The availability of the AtF3'H gene and promoter sequence will allow us to study the coregulation of a complete set of flavonol and anthocyanidin biosynthesis genes in A. thaliana, and makes in vitro synthesis of hydroxylated flavonoids more feasible.

Amino Acid Sequence↗
PubMed1999

Effect of internal thoracic artery preparation on blood loss, lung function, and pain.

BACKGROUND: Postoperative blood loss, respiratory distress, and pain after coronary artery operation were assessed in a prospective, randomized, clinical study comparing two techniques of internal thoracic artery preparation. METHODS: In group A (n = 57) the internal thoracic artery was dissected with the entire surrounding connective tissue after opening the pleura, using routine lateral pleural drainage. In group B (n = 55) a venoarterial pedicle was prepared without surrounding muscle leaving the pleura intact. We assessed blood loss, clinical outcome, lung function, location, intensity, and quality of pain 6 days and 3 months after the operation. RESULTS: Significantly higher blood loss was observed in group A (A, 608+/-58 mL; B, 470+/-48 mL; p = 0.027). Forced expiratory volume in 1 second was significantly decreased in group A 6 days after surgery (A, 76.0%+/-1.6%; B, 83.2%+/-1.6%; p = 0.020). The forced expiratory volume in 1 second correlated to inspiratory vital capacity, which confirmed the advantage of the venoarterial technique (A, 0.771+/-0.021; B, 0.832+/-0.020; p = 0.003). Vital capacity was significantly higher in the venoarterial group at 3 months (A, 85.2%+/-2.1%; B, 98.5%+/-1.2%; p = 0.009), but not on postoperative day 6. The incidence of pleural effusion and atelectasis was significantly higher in group A (effusion: A, 52.6%; B, 23.6%; p = 0.002; atelectasis: A, 42.1%; B, 20.0%, p = 0.015). Sternal pain (A, 36.8%; B, 9.1%; p = 0.001) and suspenders pain (A, 33.3%; B, 7.3%; p = 0.001) occurred more often in group A. When using a multidimensional pain score, patients in group A experienced significantly sharper (6 days: A, 6.7+/-0.3; B, 3.3+/-0.2; p = 0.018; 3 months: A, 3.5+/-0.3; B, 1.4+/-0.3; p = 0.046) and more annoying pain (6 days: A, 7.6+/-0.2; B, 2.7+/-0.1; p = 0.036; 3 months: A, 6.6+/-0.3; B, 2.3+/-0.2; p = 0.040). CONCLUSIONS: These results demonstrate that the venoarterial preparation technique is superior to conventional internal thoracic artery preparation regarding postoperative blood loss, lung function, and pain.

Female↗
PubMed1999

Synthetic protein treated versus heparin coated cardiopulmonary bypass surfaces: similar clinical results and minor biochemical differences.

OBJECTIVE: Complications associated with cardiopulmonary bypass (CPB) have gained more attention due to increased interest in coronary artery bypass grafting without CPB. The impact of heparin coating of CPB circuits has been discussed controversially. The present study examines if the treatment of the oxygenator surface with a synthetic protein may serve as an alternative to a completely heparin coated circuit. METHODS: Fifty-eight patients undergoing coronary artery bypass grafting with CPB were randomly assigned to completely heparin coated circuits or synthetic protein treated oxygenators in a double blind protocol, focussing on the inflammatory reaction resulting in membrane damage, coagulation changes and markers of cerebral injury or dysfunction. Treatment groups did not differ as to preoperative demographics, and intraoperative clinical data. Patients with any neurologic disease or risk factors for cerebral dysfunction were not included in the study. RESULTS: Postoperative clinical data did not differ between groups. Both surface treatments resulted in similar coagulation activation, hyperfibrinolysis and disseminated intravascular coagulation. Platelet count displayed a difference in favour of the heparin coated group (P = 0.029). Increased leukocyte activation reflected by rising myeloperoxidase concentrations on CPB was present in both synthetic protein and heparin coating groups. Interleukins 6 and 8 reacted similarly, but interleukin 8 increased significantly more (P = 0.0061) at the end of surgery in patients treated with protein treated oxygenators. The same pattern was observed for complement activation as determined by total complement complex (P = 0.006). Both surface changes resulted in moderately increased S-100B protein and neuron specific enolase, without difference between groups. Both markers did not reach concentrations associated with clinical manifestation of cerebral injury. CONCLUSIONS: These results in routine patients with short bypass time, imply that protein treated oxygenators are associated with a limited increase of biochemical markers similar to heparin coating. However, significantly lower interleukin 8 release and complement activation can be achieved by heparin coating. The protein treatment is a standard feature of the oxygenator examined in both groups. It is not associated with additional cost and therefore appropriate for use in routine patients.

Aged↗
PubMed1999

Cloning and expression of flavone synthase II from Gerbera hybrids.

In Gerbera hybrids, flavone synthesis is controlled by the locus Fns. The responsible enzyme, flavone synthase II, belongs to the NADPH-dependent cytochrome P450 monooxygenases. From two different chemogenetic defined Gerbera lines with the dominant (fns +.) or recessive (fns fns) alleles at the locus Fns, a cytochrome P450 fragment (CypDDd7a) was isolated using a differential display technique with upstream primers based on the conserved heme-binding region of cytochrome P450 proteins. The full-length cDNA (CYP93B2) which contained the open-reading frame and part of the CypDDd7a sequence was isolated via 5'-RACE and end-to-end PCR with gene specific primers. Northern blot analysis of total RNA of Gerbera hybrids indicated that the CYP93B2 gene was only transcribed in lines with the dominant allele fns + and that the transcript levels during flower development are in agreement with the measured enzyme activity of FNS II and flavone accumulation. Microsomes from yeast cells expressing CYP93B2 catalysed the direct formation of [14C]-flavones from the respective [14C]-flavanones. Thus, CYP93B2 was shown to encode flavone synthase II. This is the first report of the isolation and expression of a functional FNS II cDNA clone from any species. The comparison of amino acid sequences revealed that CYP93B2 had 54% identity with the sequence of CYP93B1, which has recently been reported as a (2S)-flavanone 2-hydroxylase of Glycyrrhiza echinata L.

Amino Acid Sequence↗
PubMed1999

[Ventricular rupture after blunt thoracic trauma].

In a collision with a motor-car, a pedestrian suffered multiple injuries and a blunt trauma to the thorax. Immediately after the accident, the patient was haemodynamically instable and needed resuscitation several times, without lasting success. The coroner's office found that cardiac tamponade from a ruptured right ventricle was the cause of death. The incidence of ventricular rupture due to blunt trauma in motor-car accidents is about 10 to 15%. Since definite treatment is not possible at the site of the accident, the patient must be taken immediately to a cardio-surgical hospital after initial stabilization. Unfortunately, preclinical diagnosis of ventricular rupture is difficult. In this context, the increasing availability in ambulances of a 12-channel ECG, a highly sensitive diagnostic tool, represents significant progress. Cases like the one described above should be discussed at mortality conferences of pathologists, coroners and emergency physicians to increase awareness of this problem. Only if the possibility of cardiac rupture is considered and ruled out early in cases of massive multiple injuries with haemodynamic instabilities, will decrease the apallingly high lethality figures.

Adult↗
PubMed1998

Nitric oxide inhalation in acute pulmonary hypertension after cardiac surgery reduces oxygen concentration and improves mechanical ventilation but not mortality.

Impaired right-ventricular function may benefit from afterload reduction. Inhalation of nitric oxide (NO) reduces pulmonary hypertension without systemic circulatory depression. Influence of NO inhalation on oxygenation, ventilation, and hemodynamic parameters in 10 patients with acute pulmonary hypertension after cardiac surgery was examined in this study. Ten patients without NO treatment served as a control group. NO patients showed significantly improved oxygenation and recovery of right-ventricular function. Pulmonary artery pressure (12.8%), inspiratory oxygen demand (34.7%), PEEP (13.2%), and inspiration time (18.8%) decreased significantly during inhalation of nitric oxide. Mortality in both groups was identical. We therefore conclude that NO, by improving oxygenation and right-ventricular function, temporarily reduces invasiveness of mechanical ventilation. Reduction of invasiveness of ventilation did not influence mortality as compared with patients who did not receive NO. To finally estimate the benefit of NO inhalation, larger patient groups need to be examined.

Administration, Inhalation↗
PubMed1997

Restricted attentional capacity within but not between sensory modalities.

Restrictions to attentional capacity are revealed by the interference that commonly results when two sensory inputs must be identified at the same time. To investigate this phenomenon within and between modalities, we presented streams of visual and/or auditory inputs, containing occasional targets to be identified and recalled. For two visual or two auditory streams, identification of one target produced a sustained reduction in the ability to identify a second, the period of interference lasting for several hundred milliseconds. Subjectively, when attention was assigned to one target it was temporarily unavailable for another. In contrast, there was no such time-locked interference between targets in different modalities. The results suggest a modality-specific restriction to concurrent attention and awareness; visual attention to one simple target does not restrict concurrent auditory attention to another.

Acoustic Stimulation↗
PubMed1997

Heparin-induced thrombocytopenia type II: perioperative management using danaparoid in a coronary artery bypass patient with renal failure.

An 84-year-old patient with heparin-induced thrombocytopenia (HIT), global cardiac decompensation, and acute renal failure underwent a cardiosurgical intervention using an extracorporeal circuit. For systemic anticoagulation danaparoid (Orgaran) was applied as a heparin substitute preoperatively and maintained for systemic anticoagulation during ECC despite it being eliminated by the kidney. The postoperative recovery was prolonged due to bleeding complications. During cardiopulmonary bypass (216 min) the target level of anti-factor Xa was 1.5 UI/ml. This required continuous infusion and an occasional bolus of danaparoid. Coagulation in the extracorporeal circuit was observed twice at plasma levels below 1.4 IU/ml. There were no thromboembolic or neurologic events. We did not retransfuse blood from the extracorporeal circuit or the cardiotomy reservoir after bypass, but because elimination of danaparoid was impaired in this patient and there is no neutraliser available antifactor Xa postoperatively exceeded 0.6 IU/ml for 30 hours. Diffuse bleeding with tamponade resulted. Weaning the patient from the respirator was achieved 12 hours after the last re-exploration. From the 4th postoperative day 750 IU of danaparoid were administered twice daily subcutaneously for thrombosis prevention. On the 6th postoperative day discharge from the ICU was possible. We conclude that the application of danaparoid for cardiopulmonary bypass in patients suffering from acute renal failure may be complicated by hemorrhage.

Acute Kidney Injury↗
PubMed1995

Cytologic diagnosis of cat scratch disease (CSD) by fine-needle aspiration.

Cat scratch disease (CSD) is usually a benign, self-limited lymphadenitis, characterized by suppurative granulomas. It can, however, produce a wide spectrum of clinical symptoms and cytologic changes and be the source of diagnostic dilemmas. Identification of pleomorphic bacilli (PB) with silver impregnation stains aids in the diagnosis, but this has not been well documented in cytologic preparations or in cases without the classic morphologic changes. We reviewed 13 aspirations from eight patients (aged 13-36 yr) occurring over a 15 mo time period, all clinically or cytologically suspicious for CSD. Sites included: axilla (6), parotid (3), epitrochlear (1), neck (1), submental (1), and intraclavicular (1) nodes. Neoplasia was initially suspected clinically in 38% of the cases. All but two patients had cat exposure on subsequent interview. The cytologic differential included bacterial abscess and lymphoproliferative disorders in 31%. Neither granulomas nor suppurative inflammation were seen in all cases. Changes included: granulomas (77%), PMNs (62%), dispersed epithelioid histiocytes (46%), and suppurative granulomas (38%). A modified silver stain (Modified Steiner, Sigma Diagnostics, St. Louis, MO) was performed on all specimens. Silver positive organisms were seen in 69% of cases and were not limited to those preparations with suppurative granulomas. Fine-needle aspiration biopsy (FNAB) is an effective method for diagnosing CSD despite its heterogeneous appearance; and, when combined with clinical information and silver staining, may obviate the need for excision.

Adolescent↗
PubMed1994

Efficiency of a new radiant heater for postoperative rewarming.

Effective rewarming devices have only become available recently. This investigation compares the efficiency of an new overhead radiant heater (ARAGONA Thermal Ceilings TM, CTCX, 1000 W) with that of an electric blanket (50 W) or a standard hospital blanket. 35 patients undergoing postoperative assisted ventilation and continued sedation were randomly assigned to one of the treatments. Shivering, oxygen uptake, heart rate and invasive blood pressure were measured and the increase in total body heat minus body heat production was calculated as heat balance. Results are given as medians (range). Subcutaneous temperatures were taken to calculate the mean skin temperature. The evaluation was undertaken for an oesophageal temperature interval of 35 degrees to 37 degrees C. All groups exhibited a similar mean oxygen uptake i.e. thermogenesis (3.5 (2.7-4.0) ml.kg-1.min-1, 3.3 (2.7-4.9) ml.kg-1.min-1;3.2 (2.4-5.1) ml.kg-1. min-1) which correspond to a resting energy expenditure. The time of rewarming of the radiant heat treated group (n = 12) (100 (76-143) min) for this interval was significantly reduced in comparison to both other groups (183 (116-320) min; 231 (115-340) min). A slightly positive heat balance was only achieved in the group treated by radiant heat, indicating that all metabolic heat was conserved or heat losses were compensated by transfer of external heat. Shivering was significantly reduced in the radiant heater group whereas the rate pressure product was insignificantly higher. We did not find any significant effect for the electric heating blanket in comparison to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗