Biomedical subjects

A Hellberg

Publications and source records attributed to A Hellberg.

At least 19 recordsLinked to original sources

PubMed2005

A clue to the basis of allelic enhancement: occurrence of the Ax subgroup in the offspring of blood group O parents.

Apparent deviation from Mendelian rules of blood group inheritance is rarely observed. Blood group O parents with children expressing weak A subgroups have occasionally been described but not explained. A detailed serological investigation of such a family is described here. The ABO locus was analysed by PCR-ASP/restriction fragment length polymorphism genotyping and DNA sequencing. The propositus' RBCs were very weakly agglutinated with monoclonal anti-A but distinctly with polyclonal anti-A,B, i.e. typical for Ax. Serum anti-A1 (titre 4) and -B were present. Her parents' blood groups were both clearly O, with titres of serum anti-A1, and -A at 16 and 4, respectively. Adsorption/ elution studies demonstrated A antigen on the daughter's cells only. The ABO genotypes were: mother, AxO1; father, O1vO2; and propositus, AxO2. The Ax allele was an A1-O1v hybrid allele with a crossing-over breakpoint between positions 235 and 446 in intron 6 (Ax-4). Compared to the A1 glycosyltransferase, this allele predicts a protein with two amino acid substitutions (Phe216Ile and Met277Val) known to yield either weakly expressed or no A antigen on RBCs. This study suggests that the nature of the ABO allele in trans can influence A antigen expression, a phenomenon previously described as allelic enhancement (or reinforcement). Potential mechanisms for this are discussed.

ABO Blood-Group System↗

PubMed2005

Blood group genotype analysis for the quality improvement of reagent test red blood cells.

BACKGROUND AND OBJECTIVES: Reagent red blood cells (RBCs) for antibody detection should express certain important antigens as a double dose, that is, the donors must be homozygous for the corresponding alleles. Traditionally, dose is determined by serological typing and known allele frequencies. However, RHD zygosity cannot be predicted serologically owing to the absence of an antithetical antigen, and FY zygosity is confounded by two variant haplotypes, FY*0 and FY*X. Furthermore, lack of reagents hampers our ability to type for some clinically important antigen pairs such as Do(a)/Do(b). MATERIALS AND METHODS: Genomic DNA was isolated from reagent RBC samples. Established, validated methods were used to determine the RHD, FY, and DO genotypes. RESULTS: Three of 52 D+ samples gave results that differed from the predicted genotype: two presumed R(1)R(1) samples and an R(2)R(2) sample were shown to be R(1)r' and R(2)r'', respectively. Five of 59 samples that were from presumed homozygotes for either FY*A or FY*B were heterozygous, together with either FY*X (three samples) or FY*0 (two samples). Seventy-five samples tested for DO were DO*A/A (n = 14), DO*A/B (n = 39), or DO*B/B (n = 22). CONCLUSIONS: The results show that serologically determined RhD and Duffy phenotypes of reagent RBCs are unreliable and that antigens we thought were represented as a double dose were single dose. The addition of Dombrock genotyping provides information which is useful in antibody identification. We conclude that selected genotype analyses are a valuable quality assurance measure to ensure that reagent RBCs comply with national and international recommendations for test sensitivity.

ADP Ribose Transferases↗

PubMed2005

Novel glycolipid variations revealed by monoclonal antibody immunochemical analysis of weak ABO subgroups of A.

BACKGROUND AND OBJECTIVES: The chemical basis of the subgroups of A is largely unknown. We used thin-layer chromatography immunochemical staining techniques together with a range of characterized monoclonal reagents to analyse glycolipids isolated from a variety of weak subgroups. MATERIALS AND METHODS: Glycolipids isolated from red cells collected from nine genetically defined individuals of the rare subgroups of A, including a novel A(3) allele (A(2) 539G>A) not described previously, were subjected to a highly sensitive thin-layer chromatographic immunochemical analysis. RESULTS: Semicharacterized monoclonal antibodies revealed that, in addition to the expected quantitative differences between common phenotypes and the weak subgroups, qualitative glycolipid differences (or at least an apparent qualitative basis), caused by major changes in the ratios of different structures exist. Specifically it was found that the weakest A-expressing samples (A(el) phenotype) appeared to express an unusual A structure in the 8-12 sugar region. Variable expression of several structures in one of the A weak samples were suggestive of novel blood group A structures. CONCLUSIONS: Although no structural characterization could be undertaken, the results are clearly indicative that the variant glycosyltransferases of the rare ABO subgroups are not only inefficient, but they may potentially synthesize novel ABO structures.

ABO Blood-Group System↗

PubMed2004

The Fenyö-Lindberg scoring system for appendicitis increases positive predictive value in fertile women--a prospective study in 455 patients randomized to either laparoscopic or open appendectomy.

BACKGROUND: Suspected appendicitis is one of the most common indications for acute laparotomy or laparoscopy. The negative laparotomy and laparoscopy rates are high, often in the range of 15-30%, and especially high in some groups of patients such as women of child-bearing age and young patients. Different scoring systems have been introduced in order to improve diagnostic accuracy. The aim of the present study was to analyse the outcome of the Fenyö-Lindberg scoring system in a prospectively randomized multicenter trial and to analyze how well the score performed in stratified subgroups. METHODS: The variables of the Fenyö-Lindberg scoring system were collected in a prospective study comparing laparoscopic and open surgery in suspected appendicitis and with four participating centers. None of the hospitals had used the scoring system previously. Since surgeons were unfamiliar with the score, they could not use it as a diagnostic aid. When comparing the score with the clinical outcome, retrospectively, the investigators interpreting the score were blinded regarding the surgical outcome. RESULTS: Positive predictive value (PPV) of the Fenyö-Lindberg score was higher than that of the surgeon's clinical diagnosis in the patient cohort [0.90 vs 0.79 (p < 0.001)]. The score demonstrated an improvement of PPV in women [0.83 vs 0.70 (p < 0.01)]. PPV was increased in women between 15 and 50 years of age. In women aged 15-30 years and 31-50 years PPV increased from 0.69 to 0.82 and 0.68 to 0.86, respectively (p < 0.01). Both the sensitivity (0.77) and the specificity (0.69) of the score were, however, low. CONCLUSION: The Fenyö-Lindberg score is an inexpensive clinical tool that may improve the diagnostic accuracy for acute appendicitis in women of childbearing age, which is a group of patients where the diagnostic accuracy usually is low and where the arsenal of diagnostic tools such as computed tomography is limited because of radiation. The low specificity of the score in women of childbearing age must, however, be kept in mind.

Adolescent↗

PubMed2004

Genetic heterogeneity at the glycosyltransferase loci underlying the GLOB blood group system and collection.

The aim of this study was to further explore the molecular genetic bases of the clinically important but rare blood group phenotypes p, P(1) (k) and P(2) (k) by analysis of the 4-alpha-galactosyltransferase (P(k)) and 3-beta-N-acetylgalactosaminyltransferase (P) genes responsible for synthesis of the related P(k) (Gb(3)) and P (Gb(4)) antigens respectively. Lack of these glycolipid moieties is associated with severe transfusion reactions and recurrent spontaneous abortions but also offers immunity against certain infectious agents. Blood samples from 20 p and 11 P(1) (k) or P(2) (k) individuals of different geographic and ethnic origin were investigated. DNA sequencing by capillary electrophoresis was performed following amplification of the coding regions in the P(k) or P genes. In the P(k) gene, nine novel and five previously described mutations were detected. One of the newly found mutations introduced an immediate stop, five shifted the reading frame introducing premature stop codons and three were missense mutations causing amino acid substitutions in conserved regions of the transferase. Four new and two previously described mutations in the P gene were found. Three of the novel alleles reported here carried nonsense mutations whilst the fourth allele had a missense mutation. The finding of 13 novel mutations in 14 alleles emphasizes further the genetic heterogeneity at the glycosyltransferase loci underlying the GLOB blood group system and collection.

Amino Acid Sequence↗

PubMed2002

Recombinant expression and purification of an enzymatically active cysteine proteinase of the protozoan parasite Entamoeba histolytica.

Cysteine proteinases and in particular cysteine proteinase 5 (EhCP5) of Entamoeba histolytica are considered important for ameba pathogenicity. To study EhCP5 in more detail a protocol was elaborated to produce considerable amounts of the enzyme in its active form. The protein was expressed in Escherichia coli as a histidine-tagged pro-enzyme and purified to homogeneity under denaturing conditions in the presence of guanidine-HCl using nickel affinity chromatography. Renaturation was performed by 100-fold dilution in a buffer containing reduced and oxidized thiols, which led to soluble but enzymatically inactive pro-enzyme. Further processing and activation was achieved in the presence of 10 mM DTT and 0.04% SDS at 37 degrees C. Recombinant enzyme (rEhCP5) was indistinguishable from native EhCP5 purified from E. histolytica lysates. Both runs in SDS-PAGE under reducing and nonreducing conditions at positions corresponding to 27 and 29 kDa, respectively, had the same pH optima and displayed similar specific activity against azocasein. Moreover, both enzymes were active against a broad spectrum of biological and synthetic substrates such as mucin, fibrinogen, collagen, human hemoglobin, bovine serum albumin, gelatin, human IgG, Z-Arg-Arg-pNA, and Z-Ala-Arg-Arg-pNA, but not against Z-Phe-Arg-pNA. The identity of rEhCP5 as a cysteine proteinase was confirmed by inhibition with specific cysteine proteinase inhibitors. In contrast, various compounds known to specifically inhibit aspartic, metallo, or serine proteinases had no effect on rEhCP5 activity.

Animals↗

PubMed2002

Phenotype prediction by DNA-based typing of clinically significant blood group systems in Jordanian blood donors.

BACKGROUND AND OBJECTIVES: During the past 10 years several DNA-typing methods have been developed to complement routine serological typing for determination of polymorphisms in the ABO, RH, KEL, JK and FY blood group genes. However, the molecular basis of blood groups can differ widely between ethnic groups. The purpose of this study was to evaluate selected DNA-based methods for phenotype prediction in a population not previously investigated. MATERIALS AND METHODS: Blood samples from a random sample of Jordanian blood donors were collected and red cells isolated from these blood samples were phenotyped for common ABO (n = 150) and KEL/FY/JK (n = 90) antigens. RHD-negative and -positive donors were selected for RH typing (n = 120 and 30, respectively). DNA was prepared and blood group genotyping performed according to selected methods in current use. Discordant samples required further investigation by extended serology and DNA sequencing. RESULTS: The degree of concordance between phenotype and genotype was high, but some exceptions were noted. Two of 14 A2/A2B samples lacked all mutations associated with known A2 alleles of the ABO system. RH typing revealed four samples with the c(cyt48) marker, causing false-positive RHC typing. A single D-negative sample was positive for D-specific exon 10 markers. The RHD pseudogene was not found in the 150 donors tested. Nine samples revealed discrepancies that were associated with unknown silent or weakly expressing Fyb-like alleles. CONCLUSIONS: With the exception of the FY system, we conclude that the molecular background of the clinically important blood group antigens studied here is similar to that reported for Caucasoids.

Alleles↗

PubMed2002

Duplex scanning as the sole preoperative imaging method for infrainguinal arterial surgery.

OBJECTIVE: to evaluate preoperative duplex as the sole investigation prior to lower limb reconstruction. Design retrospective analysis. MATERIALS AND METHODS: between January 1995 and December 1999, 157 of 329 surgical interventions for chronic infrainguinal arterial or aneurysmal disease were performed without preoperative angiography. RESULTS: in patients undergoing femoral artery endarterectomy, the extent of the stenosis and the status of the distal deep femoral artery were correctly diagnosed with duplex scanning in all but one patient. Duplex scan findings in patients undergoing infrainguinal bypass procedures were in agreement with the findings obtained from on-table angiography in regard to the selection of optimal outflow anastomotic sites in 123 (98%). Duplex scanning correctly evaluated the status of runoff in 113 (90%). There were no significant differences in 30-day occlusion rate and patency at 12 months between reconstructions performed with and without preoperative angiography. CONCLUSION: in patients with conclusive duplex scan findings there is no need to perform angiography prior to lower limb reconstruction.

Adolescent↗

PubMed2002

Selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty with duplex scanning.

AIM: To evaluate the role of duplex scanning in the selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty (PTA). MATERIAL AND METHODS: From January 1995 through May 2000, 702 patients (952 limbs), with chronic lower extremity ischemia due to infrainguinal atherosclerotic disease diagnosed by duplex scanning, were retrospectively studied. Diagnostic angiography (130 limbs) or infrainguinal PTA (108 limbs) was performed in 238 limbs. Two investigators retrospectively analyzed the duplex examinations and angiographies in a blinded manner and used similar criteria for the interpretation of lesions suitable or not suitable for PTA. RESULTS: The superficial femoral, popliteal and crural artery lesions were correctly selected for PTA in 85%, 66% and 32%, respectively. The accuracy, sensitivity, specificity, negative predictive value and positive predictive value of duplex scanning to appropriately categorize femoropopliteal lesions as suitable or unsuitable for PTA were 89%, 83%, 92%, 94% and 78%, respectively. The accuracy of duplex scanning for predicting the performance of infrainguinal PTA was 83%. CONCLUSION: Duplex scanning has an important impact on the selection of treatment modalities in limbs with infrainguinal arterial occlusive disease. Femoropopliteal lesions can be reliably selected to PTA according to duplex scan findings.

Aged↗

PubMed2001

Biomarkers of free radical injury during spinal cord ischemia.

Plasma and urinary levels of 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha) were analysed at baseline and during the ischemia-reperfusion period in experimental spinal cord ischemia. A significant and immediate increase of 8-iso-PGF(2alpha) in plasma at the start and up to 60 min, and in the urine at 90-150 min following ischemia indicate an association of oxidative injury. The inflammatory response indicator 15-keto-dihydro-PGF(2alpha) in plasma increased significantly at the start and up to 60 min after ischemia. No such increase was seen in animals with no spinal cord ischemia. Thus, free radical mediated and cyclooxygenase catalysed products of arachidonic acid are increased during spinal cord ischemia as a consequence of oxidative injury and inflammation.

Animals↗

PubMed2001

Genomic analysis of clinical samples with serologic ABO blood grouping discrepancies: identification of 15 novel A and B subgroup alleles.

Since the cloning in 1990 of complementary DNA corresponding to messenger RNA transcribed at the blood group ABO locus, polymorphisms and phenotype-genotype correlations have been reported by several investigators. Exons 6 and 7, constituting 77% of the gene, have been analyzed previously in samples with variant phenotypes but for many subgroups the molecular basis remains unknown. This study analyzed 324 blood samples involved in ABO grouping discrepancies and determined their ABO genotype. Samples from individuals found to have known subgroup alleles (n = 53), acquired ABO phenotypes associated with different medical conditions (n = 65), probable chimerism (n = 3), and common red blood cell phenotypes (n = 109) were evaluated by ABO genotype screening only. Other samples (n = 94) from apparently healthy donors with weak expression of A or B antigens were considered potential subgroup samples without known molecular background. The full coding region (exons 1-7) and 2 proposed regulatory regions of the ABO gene were sequenced in selected A (n = 22) or B (n = 12) subgroup samples. Fifteen novel ABO subgroup alleles were identified, 2 of which are the first examples of mutations outside exon 7 associated with weak subgroups. Each allele was characterized by a missense or nonsense mutation for which screening by allele-specific primer polymerase chain reaction was performed. The novel mutations were encountered in 28 of the remaining 60 A and B subgroup samples but not among normal donors. As a result of this study, the number of definable alleles associated with weak ABO subgroups has increased from the 14 previously published to 29.

ABO Blood-Group System↗

PubMed2001

Laparoscopic vs open appendectomy in overweight patients.

BACKGROUND: Laparoscopic appendectomy (LA) has been associated with a faster recovery and less postoperative pain than the open technique. However, few data are available on the clinical outcome of LA in overweight patients. METHODS: A group of 106 patients with a body mass index (BMI) > 26.4, representing the upper quintile of 500 prospectively randomized patients, were included in the study. They were randomized to undergo either laparoscopic or open appendectomy (OA). Operating and anesthesia times, postoperative pain, complications, hospital stay, functional index (1 week postoperatively), sick leave, and time to full recovery were documented. RESULTS: In OA, the operating time for overweight patients was significantly longer than that for patients in the normal weight range (40 vs 35 min, p < 0.05). In LA, there was no difference in operating time between the normal and overweight patients. Overweight patients who underwent LA had longer operating and anesthesia times than their OA counterparts (55 vs 40 min, p < 0.001; and 125 vs 100 min, p < 0.001, respectively). Postoperative pain was significantly greater in overweight patients who underwent OA than in those treated with the laparoscopic technique. Postoperative pain was also significantly greater in overweight patients subjected to OA than in patients of normal weight after 4 weeks; the clinical significance may, however, be of less importance since the values are low (0.26 vs 0.09, p < 0.05). There were no significant differences between the two operating techniques in terms of complications. Hospital stay was longer for overweight patients than for normal-weight patients undergoing OA (3.0 vs 2.0, p < 0.01). The functional index did not differ between any group of patients. Sick leave was longer for overweight patients who underwent OA than for normal-weight patients treated with the same technique (17 vs 13 days, p < 0.01). In the laparoscopic group, however, there were no differences between the overweight and normal-weight patients. Time to full recovery was greater in overweight patients subjected to OA than in the overweight patients in the LA group (22 vs 15 days, p < 0.001). CONCLUSION: In this study, overweight patients who were submitted to LA had less postoperative pain and a faster postoperative recovery than overweight patients who had OA. LA also abolished some of the negative effects that overweight had on operating time, hospital stay, and sick leave with the open technique. However, anesthesia and operating times were significantly longer in LA for both overweight patients and those with a normal BMI.

Adolescent↗

PubMed2001

Overexpression of cysteine proteinase 2 in Entamoeba histolytica or Entamoeba dispar increases amoeba-induced monolayer destruction in vitro but does not augment amoebic liver abscess formation in gerbils.

To study the role of cysteine proteinases in the pathogenicity of Entamoeba histolytica, we have attempted to overexpress the three main cysteine proteinases (EhCP1, EhCP2, EhCP5) of this parasite in trophozoites of E. histolytica as well as in non-pathogenic Entamoeba dispar by episomal transfection. Although each of the corresponding coding sequences were cloned in identical expression plasmids, we were unable to overexpress EhCP1 and EhCP5, respectively, but could substantially induce expression of EhCP2 in both amoeba species by sevenfold, leading to a threefold increase in total cysteine proteinase activity. Overexpression of EhCP2 did not influence expression of other cysteine proteinases and could be attributed to an increase of a single 35 kDa activity band in substrate gel electrophoresis. In contrast to previous findings, which indicated that amoeba cysteine proteinases are involved in erythrophagocytosis and liver abscess formation, cells overexpressing EhCP2 showed no difference in erythrophagocytosis or liver abscess formation compared with respective controls. However, overexpression of EhCP2 in both amoeba species resulted in a marked increase of in vitro monolayer destruction.

Animals↗

PubMed2001

Monitoring of intrathecal oxygen tension during experimental aortic occlusion predicts ultrastructural changes in the spinal cord.

OBJECTIVE: To study the correlation between intrathecal PO2 and ultrastructural changes in the spinal cord during thoracic aortic occlusion in pigs. MATERIAL AND METHODS: In 18 pigs, online intrathecal oxygenation was monitored by a multiparameter Paratrend catheter (Biomedical Sensors, High Wycombe, United Kingdom) during 60 minutes' clamping of the proximal and distal descending thoracic aorta. The animals were randomly divided into 2 groups (A and B) depending on the level of distal aortic clamping. Distal aortic perfusion was restored through an aorto-iliac shunt, which also maintained low thoracic segmental perfusion of the spinal cord in group B. Perfusion-fixation technique was used before harvesting the spinal cord specimens, which later were evaluated with light and electron microscopy by an independent observer. Intrathecal parameters were interpreted as normal if PO2 was more than 0.8 kPa and PCO2 was less than 12 kPa, as intermediate ischemia if PO2 was 0.8 or less or PCO (2) was more than 12 kPa, and as absolute ischemia if PO2 was 0.8 or less and PCO2 was more than 12 kPa. RESULTS: Among 6 animals with ultrastructural changes of absolute spinal cord ischemia-reperfusion injury, 5 also had absolute ischemia according to variables derived by the Paratrend catheter. The 2 methods were in agreement in 3 of 5 animals with intermediate ischemia-reperfusion changes and in 5 of 6 animals with normal findings. The accuracy of cerebrospinal fluid PO2 and PCO2 to predict electron microscopy-verified intermediate or absolute ischemia-reperfusion injury was 94%. CONCLUSIONS: Monitoring of intrathecal PO2 after clamping of the descending aorta correlated with ultrastructural changes in the spinal cord in this pig model.

Animals↗

PubMed2001

Aspects of the spinal cord circulation as assessed by intrathecal oxygen tension monitoring during various arterial interruptions in the pig.

OBJECTIVE: We sought to study the effect of various modes of interruption of the spinal cord blood supply on intrathecal oxygenation. METHODS: In 24 pigs intrathecal PO (2), PCO (2), and pH were continuously monitored with a multiparameter catheter (Paratrend 7, Biomedical Sensors; Diametrics Medical, Inc, St Paul, Minn) during and after aortic crossclamping or selective interruption of segmental arteries and proximal collateral circulation. RESULTS: Proximal aortic clamping (n = 6) produced complete ischemia, whereas a second clamp close to the celiac trunk (n = 4) partly protected against spinal cord ischemia. This is explained by prevention of the steal phenomenon in the excluded part of the aorta. Adding clamps to the subclavian arteries (n = 6) created complete spinal ischemia as the collateral circulation was interrupted. In another group (n = 4) all segmental arteries below T5 were occluded with no reaction in the intrathecal variables. Additional selective clamping of supreme intercostal arteries (n = 4) showed the relative importance of the subclavian and vertebral collateral pathways. CONCLUSIONS: Continuous intrathecal PO (2) was monitored during various modes of interruption of the spinal cord blood supply. This provided insight into the ischemia mechanisms and relative importance of the segmental contribution and proximal collateral pathways of the spinal cord circulation in pigs. A short literature review is given, and aspects of comparative anatomy are discussed.

Animals↗

PubMed2001

Percutaneous transluminal angioplasty of the femoropopliteal arteries in limbs with chronic critical lower limb ischemia.

PURPOSE: The aim of the study was to evaluate the results of percutaneous transluminal angioplasty (PTA) of femoropopliteal arteries in patients with subcritical or critical lower limb ischemia. MATERIALS AND METHODS: Ninety-two patients underwent 121 PTA procedures, 68 were of the superficial femoral artery (SFA), 13 of the popliteal and 40 of both arteries. Fifty-seven procedures were performed for treatment of occlusions. Eighty-four patients (94 procedures) were monitored with duplex scanning. RESULTS: Technical success rate was 88%. Primary success rates at 12 and 60 months in the whole series were 40% and 27%, respectively. The primary success rate in limbs with SFA occlusion of longer than 5 cm was only 12% after 5 years compared with 32% if the occlusion was </= 5 cm in length (P <.01). The primary success rate at 60 months was 53% in limbs with single SFA stenosis and 42% in those with multiple stenoses (P = NS). Limb salvage rate for combined endovascular and vascular interventions was 86% at 5 years. The overall survival rate was 51% at 5 years. CONCLUSION: The results of femoropopliteal PTA performed for treatment of subcritical or critical lower limb ischemia seemed to be inferior to the results of infrainguinal bypass grafting reported in literature. However, because the PTA procedure does not preclude the performance of bypass grafting, it might be an alternative to surgical intervention in limbs with stenotic femoropopliteal lesions. PTA might also be considered in patients with high surgical risk and limited life expectancy, having short occlusive lesions (< 5 cm).

Adult↗

PubMed2001

Conversion from laparoscopic to open appendicectomy: a possible drawback of the laparoscopic technique?

OBJECTIVE: To analyse the reasons for, and outcome of, conversion from laparoscopic to open appendicectomy and to identify factors that may predict the need for conversion. DESIGN: Subgroup analysis from a randomised multicentre study. SETTING: One university hospital and four county hospitals, Sweden. SUBJECTS: A total of 500 patients were randomised to laparoscopic (n = 244) or open (n = 256) appendicectomy. Thirty operations (12%) were converted to open appendicectomy. MAIN OUTCOME MEASURES: Reasons for conversion, outcome, and preoperative predictive variables. RESULTS: Difficult anatomy or the presence of an abscess were the main reasons for conversion (25/30). The incidence of perforated appendicitis was higher among patients who required conversion compared with both the open and laparoscopic group. Operating time, anaesthetic time, and duration of hospital stay were longer after conversion. Time to full recovery and length of sick leave were also longer, except for patients with perforated appendicitis. There was no difference in the complication rate. No predictive factors were identified. CONCLUSION: The main reasons for conversion were difficult anatomy and the presence of an abscess. After conversion patients recovered more slowly than those operated on laparoscopically or by primary open operation.

Adolescent↗

PubMed2001

Increased FiO2 improves intrathecal oxygenation during thoracic aortic cross-clamping in pigs.

OBJECTIVES: To investigate the effect of 100% oxygen ventilation on cerebrospinal fluid (CSF) oxygenation in 11 pigs during thoracic aortic cross-clamping. DESIGN: An aorto-aortic shunt was used for control of central hemodynamics and study of hypoperfusion by exsanguination. CSF PO2, PCO2 and pH were continuously monitored before and during clamping. The changes in hemodynamic parameters and intrathecal gas tensions in response to variations in proximal mean aortic pressure and fraction of inspired oxygen (FiO2) were recorded. RESULTS: Baseline CSF PO2 decreased from 4.8 +/- 1.9 to 2.6 +/- 2.2 kPa following aortic occlusion. Increasing FiO2 to 1.0 resulted in a significant increase in CSF PO2 to 4.1 +/- 3.0 with a return to 2.7 +/- 2.1 kPa after reducing FiO2 to 0.4 again. The same variations in FiO2 did not induce any significant changes in CSF PO2 during hypotension. CONCLUSION: Increased FiO2 during experimental thoracic aortic cross-clamping with stable proximal arterial pressure helps to maintain CSF PO2, whereas severe hypotension could not be compensated for by hyperoxemia.

Animals↗