South African Society of Anaesthesiologists Perioperative Patient Blood Management Guidelines 2020

Anaesthesiologists regularly request and administer blood components to their patients, a potentially life-saving intervention. All anaesthesiologists must be familiar with the indications and appropriate use of blood and blood components and their alternatives, but close liaison with haematologists and their local haematology blood sciences laboratory is encouraged. In the last decade, there have been considerable changes in approaches to optimal use of blood components, together with the use of alternative products, with a need to update previous guidelines and adapt them for anaesthesiologists working throughout the hospital system.

1 Assessing the energy status of porcine embryos by means of biodynamic imaging

Assisted reproductive technologies are powerful tools for enhancing production in livestock or treating infertility in humans. Unfortunately, the success rate of the technologies is rather low. A major reason for the poor efficiency is the lack of methods to reliably assess the developmental potential of the embryos before transfer into recipients. Therefore, a noninvasive method to ensure the selection of only the best embryos for transfer would be highly desirable. Biodynamic imaging is a compelling new microscopy that uses intracellular Doppler spectroscopy to perform label-free, noninvasive optical measurements of cellular fitness. The aim of this study was to investigate whether biodynamic imaging can be used to assess the energy status of the embryos, which may be indicative of their viability. Porcine oocytes matured invitro were parthenogenetically activated by an electrical pulse and cultured for 2 days. The parthenotes were then divided into two groups, and approximately half of them were incubated for an additional 2 days in the presence of 20mM sodium azide. Sodium azide is an inhibitor of oxidative phosphorylation and is known to block ATP production. The rest of the embryos were cultured without sodium azide and used as a control to indicate normal ATP levels. At the end of the culture period embryos that reached the 8- to 16-cell stage were evaluated by our biodynamic imaging system to assess their energy status, after which they were lysed and their ATP contents were determined by means of a bioluminescence assay. A total of 68 embryos (32 treated with the inhibitor and 36 control) were evaluated. The ATP content analysis showed that the control embryos had significantly more ATP than those treated with sodium azide as determined by Student's t-test (5.04±1.07 vs. 1.31±0.57; P<0.05). A correlative study was then completed where biodynamic biomarkers were used to classify embryos to estimate the ability of biodynamic imaging to identify embryos with high or low energy status. A set of 13 biomarkers representing each embryo as a feature vector was used to train a classifier. We found that the cross-validated classifier had a sensitivity and specificity of ~80%. In addition, a receiver-operator curve constructed by varying the ATP threshold of the independent bioluminescence assay had an area-under-the-curve of 0.81. These results indicate that biodynamic imaging is able to determine the energy status of the embryos noninvasively and has great potential in the assessment of embryo viability.

An integrative correlation of myopathology, phenotype and genotype in late onset Pompe disease

AIMS

Pompe disease is caused by pathogenic mutations in the alpha 1,4-glucosidase (GAA) gene and in patients with late onset Pome disease (LOPD), genotype-phenotype correlations are unpredictable. Skeletal muscle pathology includes glycogen accumulation and altered autophagy of various degrees. A correlation of the muscle morphology with clinical features and the genetic background in GAA may contribute to the understanding of the phenotypic variability.

METHODS

Muscle biopsies taken before enzyme replacement therapy were analysed from 53 patients with LOPD. On resin sections, glycogen accumulation, fibrosis, autophagic vacuoles and the degree of muscle damage (morphology-score) were analysed and the results were compared with clinical findings. Additional autophagy markers microtubule-associated protein 1A/1B-light chain 3, p62 and Bcl2-associated athanogene 3 were analysed on cryosections from 22 LOPD biopsies.

RESULTS

The myopathology showed a high variability with, in most patients, a moderate glycogen accumulation and a low morphology-score. High morphology-scores were associated with increased fibrosis and autophagy highlighting the role of autophagy in severe stages of skeletal muscle damage. The morphology-score did not correlate with the patient's age at biopsy, disease duration, nor with the residual GAA enzyme activity or creatine-kinase levels. In 37 patients with LOPD, genetic analysis identified the most frequent mutation, c.-32-13T>G, in 95%, most commonly in combination with c.525delT (19%). No significant correlation was found between the different GAA genotypes and muscle morphology type.

CONCLUSIONS

Muscle morphology in LOPD patients shows a high variability with, in most cases, moderate pathology. Increased pathology is associated with more fibrosis and autophagy.

The critical size of a defect in the glenoid causing anterior instability of the shoulder after a Bankart repair, under physiological joint loading

Aims

Patients with recurrent anterior dislocation of the shoulder commonly have an anterior osseous defect of the glenoid. Once the defect reaches a critical size, stability may be restored by bone grafting. The critical size of this defect under non-physiological loading conditions has previously been identified as 20% of the length of the glenoid. As the stability of the shoulder is load-dependent, with higher joint forces leading to a loss of stability, the aim of this study was to determine the critical size of an osseous defect that leads to further anterior instability of the shoulder under physiological loading despite a Bankart repair.

Patients and Methods

Two finite element (FE) models were used to determine the risk of dislocation of the shoulder during 30 activities of daily living (ADLs) for the intact glenoid and after creating anterior osseous defects of increasing magnitudes. A Bankart repair was simulated for each size of defect, and the shoulder was tested under loading conditions that replicate in vivo forces during these ADLs. The critical size of a defect was defined as the smallest osseous defect that leads to dislocation.

Results

The FE models showed a high risk of dislocation during ADLs after a Bankart repair for anterior defects corresponding to 16% of the length of the glenoid.

Conclusion

This computational study suggests that bone grafting should be undertaken for an anterior osseous defect in the glenoid of more than 16% of its length rather than a solely soft-tissue procedure, in order to optimize stability by restoring the concavity of the glenoid.

Point-of-Care Clinical Ultrasound for Medical Students

PURPOSE

Our institution has recently implemented a point-of-care (POC) ultrasound training program, consisting of an e-learning course and systematic practical hands-on training. The aim of this prospective study was to evaluate the learning outcome of this curriculum.

MATERIALS AND METHODS

16 medical students with no previous ultrasound experience comprised the study group. The program covered a combination of 4 well-described point-of-care (POC) ultrasound protocols (focus assessed transthoracic echocardiography, focused assessment with sonography in trauma, lung ultrasound, and dynamic needle tip positioning for ultrasound-guided vascular access) and it consisted of an e-learning course followed by 4 h of practical hands-on training. Practical skills and image quality were tested 3 times during the study: at baseline, after e-learning, and after hands-on training.

RESULTS

Practical skills improved for all 4 protocols; after e-learning as well as after hands-on training. The number of students who were able to perform at least one interpretable image of the heart increased from 7 at baseline to 12 after e-learning, p<0.01, and to all 16 students after hands-on-training, p<0.01. The number of students able to cannulate an artificial vessel increased from 3 to 8 after e-learning and to 15 after hands-on training.

CONCLUSION

Medical students with no previous ultrasound experience demonstrated a considerable improvement in practical skill after interactive e-learning and 4 h of hands-on training.

White matter damage is related to ataxia severity in SCA3

Spinocerebellar ataxia type 3 (SCA3) is the most frequent inherited cerebellar ataxia in Europe, the US and Japan, leading to disability and death through motor complications. Although the affected protein ataxin-3 is found ubiquitously in the brain, grey matter atrophy is predominant in the cerebellum and the brainstem. White matter pathology is generally less severe and thought to occur in the brainstem, spinal cord, and cerebellar white matter. Here, we investigated both grey and white matter pathology in a group of 12 SCA3 patients and matched controls. We used voxel-based morphometry for analysis of tissue loss, and tract-based spatial statistics (TBSS) on diffusion magnetic resonance imaging to investigate microstructural pathology. We analysed correlations between microstructural properties of the brain and ataxia severity, as measured by the Scale for the Assessment and Rating of Ataxia (SARA) score. SCA3 patients exhibited significant loss of both grey and white matter in the cerebellar hemispheres, brainstem including pons and in lateral thalamus. On between-group analysis, TBSS detected widespread microstructural white matter pathology in the cerebellum, brainstem, and bilaterally in thalamus and the cerebral hemispheres. Furthermore, fractional anisotropy in a white matter network comprising frontal, thalamic, brainstem and left cerebellar white matter strongly and negatively correlated with SARA ataxia scores. Tractography identified the thalamic white matter thus implicated as belonging to ventrolateral thalamus. Disruption of white matter integrity in patients suffering from SCA3 is more widespread than previously thought. Moreover, our data provide evidence that microstructural white matter changes in SCA3 are strongly related to the clinical severity of ataxia symptoms.

Spinocerebellar ataxia type 17 associated with an expansion of 42 glutamine residues in TATA-box binding protein gene

BACKGROUND

Spinocerebellar ataxia type 17 (SCA17) is caused by abnormal expansions of CAG/CAA trinucleotides within the TATA-box binding protein gene (TBP). The currently accepted critical threshold of abnormal expansions is ≥43.

OBJECTIVE

To investigate the minimal CAG/CAA expansion within the TBP in SCA17.

RESULTS

285 patients with autosomal-dominant ataxia were examined, and abnormal or borderline expansions of CAG/CAA within TBP in eight cases were found. Of those, four patients from three families had exactly 42 CAG/CAA trinucleotides, that is, one codon less than the currently accepted critical threshold of 43. The four patients presented with a relatively benign phenotype. All had dysdiadochokinesia and dysarthria. Mild gait ataxia was observed in three of the four patients.

CONCLUSION

The reference definition of at least 43 CAG/CAA codons for pathological SCA17 alleles should be lowered to 42.

Stages of sleep pathology in spinocerebellar ataxia type 2 (SCA2)

BACKGROUND

Autosomal dominant spinocerebellar ataxia type 2 (SCA2) bears clinical and neuropathologic similarities to sporadic multisystem atrophy (MSA) or Parkinson disease, in which sleep pathology is well documented. However, those clinical entities have a marked variability of the reported sleep disturbances, and their etiology is heterogeneous. In contrast, the study of SCA2 provides an opportunity to examine a molecularly homogeneous patient group, in which disease stages can be defined not only based on disease duration and ataxia scores, but also with regard to modulatory effects of mutation size.

OBJECTIVE

To examine the presence and progression of sleep pathology in SCA2.

METHODS

We analyzed eight patients with disease durations of 3 to 31 years, all with medium size SCA2 expansions (CAG 38 to 49), using clinical scores, sleep interviews, and video-polysomnography (VPSG) recordings.

RESULTS

Almost all patients reported good subjective sleep quality and negated incidents of REM behavior disorder (RBD). At early disease stages, however, REM without atonia in four patients' VPSG suggested subclinical RBD. This was accompanied by a consistent reduction of REM density. In three patients at later SCA2 stages, REM sleep was undetectable, whereas slow wave sleep (SWS) was markedly increased at the cost of light sleep. Periodic leg movements, apnea, or hypopnea were not prominent.

CONCLUSIONS

Progressive loss of dream recall in spinocerebellar ataxia type 2 was found and correlated with stages of REM more than non-REM pathology in video-polysomnography. These stages correspond to the progressive atrophy from the pons, nigrostriatal projection, and locus ceruleus to the thalamus.

An autosomal dominant ataxia maps to 19q13: Allelic heterogeneity of SCA13 or novel locus?

The autosomal dominant spinocerebellar ataxias (ADCAs) represent a growing and heterogeneous disease phenotype. Clinical characterization of a three-generation Filipino family segregating a dominant ataxia revealed cerebellar signs and symptoms. After elimination of known spinocerebellar ataxia (SCA) loci, a genome-wide linkage scan revealed a disease locus in a 4-cM region of 19q13, with a 3.89 lod score. This region overlaps and reduces the SCA13 locus. However, this ADCA is clinically distinguishable from SCA13.

Simultanes nichtinvasives Monitoring mit Laser-Doppler-Flussmessung und Gewebespektrometrie bei fasziokutanen Radialislappen und osteokutanen Fibulatransplantaten

AIM

In the literature currently available monitoring devices are usually divided into two major groups: those for monitoring perfusion and those for measuring tissue oxygenation. The O(2)C (oxygen to see) system combines these two ways of monitoring free flap viability. The aim of this prospective study was to determine the necessity of flap revision and when unnecessary revision can be avoided. Another point of interest was the question of whether critical values for the successful course of free flaps could be defined and in addition whether such values would differ for different flap types.

PATIENTS AND METHODS

In a prospective study 82 free flaps (61 radial forearm flaps and 21 fibula flaps) were monitored with the O(2)C monitoring unit. Measurements were carried out intraoperatively and postoperatively up to 14 days.

RESULTS

Perfusion compromise occurred in 12 (14.6%) of 82 monitored free flaps. Operative exploration was performed in seven cases, in five of them successfully. Five flaps (three radial forearm and two fibula flaps) were lost due to vascular compromise, which led to an overall success rate of 93.4%. Venous congestion was identified by a rapid increase in hemoglobin concentration of more than 30%. An abrupt decline of blood flow and hemoglobin oxygenation indicated arterial occlusion. Vascular complications were detected in all cases prior to clinical assessment with no false positive or negative results. For radial forearm flaps a hemoglobin oxygenation of 15%, a superficial flow of 10 AU, and a deep flow of 20 AU were identified as minimum values for flap viability. For fibula flaps a hemoglobin oxygenation of 10%, a superficial flow of 5 AU, and a deep flow of 15 AU were determined as minimum values.

CONCLUSION

O(2)C combines laser Doppler flowmetry and tissue spectrophotometry and for the first time allows simultaneous measurement of the microcirculatory parameters including blood flow, flow velocity, hemoglobin concentration, and hemoglobin oxygenation. We found this new noninvasive technique to be a reliable and accurate method for evaluating flap viability and improving the success rate in free flap transfer.

Reversible ischaemia after raising a radial forearm flap with ulceration of three fingers in a cigarette smoker

The radial forearm flap is a standard method for the reconstruction of intraoral defects of soft tissues. We report the case of a middle-aged man who developed ischaemia in three fingers after a fasciocutaneous radial flap had been raised. The preoperative Allen test to diagnose occlusion of radial or ulnar artery was satisfactory. Soon after the operation the patient resumed smoking and four weeks later he developed ulcers on the thumb, index, and middle fingers. Only after he had stopped smoking and been given acetylsalicylic acid and heparin did blood flow and capillary hemoglobin oxygenation increase. As a result, his radial fingers recovered completely.

Attenuation of Leukocyte Sequestration by Selective Blockade of PECAM-1 or VCAM-1 in Murine Endotoxemia

BACKGROUND

Molecular mechanisms regulating leukocyte sequestration into the tissue during endotoxemia and/or sepsis are still poorly understood. This in vivo study investigates the biological role of murine PECAM-1 and VCAM-1 for leukocyte sequestration into the lung, liver and striated skin muscle.

METHODS

Male BALB/c mice were injected intravenously with murine PECAM-1 IgG chimera or monoclonal antibody (mAb) to VCAM-1 (3 mg/kg body weight); controls received equivalent doses of IgG2a (n = 6 per group). Fifteen minutes thereafter, 2 mg/kg body weight of Salmonella abortus equi endotoxin was injected intravenously. At 24 h after the endotoxin challenge, lungs, livers and striated muscle of skin were analyzed for their myeloperoxidase activity. To monitor intravital leukocyte-endothelial cell interactions, fluorescence videomicroscopy was performed in the skin fold chamber model of the BALB/c mouse at 3, 8 and 24 h after injection of endotoxin.

RESULTS

Myeloperoxidase activity at 24 h after the endotoxin challenge in lungs (12,171 +/- 2,357 mU/g tissue), livers (2,204 +/- 238 mU/g) and striated muscle of the skin (1,161 +/- 110 mU/g) was significantly reduced in both treatment groups as compared to controls, with strongest attenuation in the PECAM-1 IgG treatment group. Arteriolar leukocyte sticking at 3 h after endotoxin (230 +/- 46 cells x mm(-2)) was significantly reduced in both treatment groups. Leukocyte sticking in postcapillary venules at 8 h after endotoxin (343 +/- 69 cells/mm2) was found reduced only in the VCAM-1-mAb-treated animals (215 +/- 53 cells/mm2), while it was enhanced in animals treated with PECAM-1 IgG (572 +/- 126 cells/mm2).

CONCLUSION

These data show that both PECAM-1 and VCAM-1 are involved in endotoxin-induced leukocyte sequestration in the lung, liver and muscle, presumably through interference with arteriolar and/or venular leukocyte sticking.

[Importance of microcirculation in plastic surgery]

The article summarizes distinct microcirculatory models for use in surgical research with a special interest to plastic surgery. Methods for the quantitative analysis of the microcirculation in burns, flaps and wounds are presented. Vascularization of biomaterials can be observed by means of the dorsal skinfold chamber model in hamsters and mice. Developing capillary sprouts can be assessed by means of videomicroscopy and angiogenetic drugs can be tested using this model. Hairless mice allow for direct, long-term observation of the microcirculation in burns as well as during healing of dermal wounds. The pathophysiology of diabetic wound healing can also be studied. A mouse model to assess flap microcirculation during ischemia/reperfusion injury with special emphasis on platelet/endothelium interaction in vivo is described. Platelets adherent to the inner vessel wall are known to trigger compromised perfusion in flaps. The model allows us to test anti-thrombotic drugs. The use of a special microscopic device (OPS imaging) allows us to study the microcirculation at sites of burn injury and chronic wounds in humans. Microcirculatory research in plastic surgery has increased the understanding of the pathophysiology of vascularization of biomaterials, wound healing and ischemia/reperfusion.

Limitationen der Blutversorgung des Hautlappens beim Facelifting

BACKGROUND

Besides nerve injuries or hematomas, one of the main risks of face lift surgery is the development of skin necrosis. We therefore investigated which arteries contribute to the blood supply of the face lift skin flap and how extensively mobilization can be performed before arterial cutaneous circulation is endangered.

MATERIAL AND METHOD

In six cadavers, selective dye injections into the branches of the carotid external artery were performed to determine the location of their vascular territories in relation to the face lift region. In another 12 cadavers, face lift flaps were raised with different extension of the undermined skin area before dye injections were performed.

RESULTS

It was shown that the facial artery provides blood supply to the area of the face lift flap by perforating vessels in the paranasal, perioral and submental regions and the transverse facial artery by a perforating vessel below the malar bone prominence. Although the perforating vessel of the transverse facial artery was transected by standard mobilization, the face lift flaps were sufficiently perfused via the paranasal and perioral perforating vessels of the facial artery alone.

CONCLUSION

We conclude that undermining of the face lift flap should not exceed the nasolabial fold to preserve the perforating vessels of the facial artery in the centrofacial region.

Botulinumtoxin zur Behandlung des gustatorischen Schwitzens

BACKGROUND

Botulinum toxin A has meanwhile become a proven method for treatment of gustatory sweating (focal hyperhidrosis, Frey's syndrome). Clear-cut recommendations regarding dosage of botulinum toxin A in Frey's syndrome are currently not available. The aim of this prospective randomized study therefore was to investigate botulinum toxin A with respect to its efficacy in Frey's syndrome, the ideal dose yielding maximal duration of the effect, and patient contentedness as well as unwanted side effects in patients of the Clinic of OMF Surgery at the Ruhr-University of Bochum.

PATIENTS AND METHOD

Twenty patients suffering from severe Frey's syndrome as a result of operations of the parotid gland were examined with the starch iodine test according to Minor. The gustatory skin areas were re-examined after intracutaneous injection of botulinum toxin A for up to 1 year. The patients ( n=20) were randomly assigned to two different treatment groups (group I: 2 MU/cm(2), n=10; group II: 3 MU/cm(2), n=10).

RESULTS

Mean sweating skin areas in the two treatment groups ranged between 39+/-9 and 32+/-12 cm(2), respectively. A single injection of 3 MU botulinum toxin A resulted in a nearly complete blockade of gustatory sweating for the observation period of 1 year. In the group treated with 2 MU botulinum toxin A, 44% of the total gustatory skin areas were still sweating, thus necessitating a second injection of botulinum toxin A in these patients.

CONCLUSION

Intracutaneous injection of botulinum toxin A represents a highly effective and minimally invasive procedure for the treatment of Frey's syndrome. This study shows for the first time that a dosage of 3 MU/cm(2) of botulinum toxin A achieves a complete and reliable blockade of gustatory sweating lasting for at least 12 months. This dose may therefore be recommended for treatment of this syndrome.

[Management of zygomatic fractures via a transconjunctival approach with lateral canthotomy while preserving the lateral ligament]

INTRODUCTION

This study reports on a modified approach to treat zygomatic fracture. For the surgical approach, a transconjunctival incision and, instead of a lateral canthotomy, a superficial incision of the skin and subcutaneous tissue was used, preserving the lateral ligament. The results are compared with those of previous techniques, especially the subciliary incision.

PATIENTS

In a prospective study, 30 patients (9 females and 21 males, mean age 32.1 years) with zygomatic fractures were operated using this approach. Mean follow-up time was 6 months after removal of the plates. Fractures were caused by trauma due to fighting, bicycle falls, or sport accidents. Follow-up radiographs were used to evaluate the position of the zygoma after reduction and rigid fixation.

RESULTS

Reduction and rigid fixation of the fractures were possible to perform in all cases. The access to the orbital floor and the exposure of the inferior and lateral rim were satisfactory and an additional latero-orbital cut was not necessary. The disadvantage of the complete incision of the lateral ligament with the necessity of intraoperative refixation and possible ectropium of the eyelid could be avoided. Injuries or infections of the cornea or the bulbus did not occur. Postoperative complications such as scar formation resulting in entropium or ectropium were not seen.

CONCLUSION

These results show that the transconjunctival approach with lateral superficial incision preserving the lateral ligament for treatment of zygomatic fractures is satisfactory in all cases of rigid fixation of both inferior and lateral rims. Because of its esthetic and functional advantages this approach has become standard in our department.

Restoration of blood flow and evaluation of corresponding angiogenic events by scanning electron microscopy after a single dose of VEGF in a model of peripheral vascular disease

The angiogenic effect of vascular endothelial growth factor (VEGF) has typically been assessed by indirect methods, including microsphere injection and angiography. Here, we use 3-D scanning electron microscopy (SEM) to directly visualize patterns of angiogenesis after a single bolus administration of VEGF in a model of peripheral vascular ischemia. Hind limb ischemia was induced by subcutaneous turniquet implantation in adult Wistar rats. The control group (group A, n = 10) was left untreated, group B (n = 10) received a single dose of VEGF (50 microg) injected in the peroneus muscle. LASER Doppler was applied for blood flow measurements. Animals were sacrificed on day 14 after ischemia induction and vascular casting was performed. Angiogenetic events such as 'tiny lateral sprouts', arcus formations', confluences and the angle of sprouting were assessed by SEM. Significant capillary sprouting was observed in both groups. VEGF-treated limbs demonstrated higher degrees of capillary growth (P = 0.01) and flow recovery (P = 0.028). 3-D-SEM showed sprouts to be more frequent in group B. Tiny lateral sprouts, which always left the mother vessel at an angle of 90 degrees and which were of small diameter and lacked imprints of endothelial cell nuclei, were more frequent in the VEGF-treated group (P = 0.018). Arcus formation was significantly higher in the treated group (P = 0.02). We have developed a simple and effective experimental model of ischemia. For the study of angiogenic phenomena, 3-D imaging of the microvasculature offers a direct and conclusive method for the study of angiogenic events.

Time gated fluorescence spectroscopy in Barrett's oesophagus

BACKGROUND AND AIMS

Specialised intestinal metaplasia and its dysplastic transformation, which precedes cancer in Barrett's oesophagus cannot be differentiated in standard gastroscopy. The aim of this study was to investigate whether laser induced protoporphyrin IX fluorescence permits the detection of specialised intestinal metaplasia and dysplasia during endoscopy and to take biopsy specimens in a guided rather than random manner.

METHODS

In 53 patients with Barrett's oesophagus 5-aminolaevulinic acid was sprayed on the mucosa. Approximately 60 to 120 minutes later, biopsy specimens were taken based on point-like measurements of delayed fluorescence intensity ratios of protoporphyrin IX in vivo. Two independent pathologists examined the 596 biopsy specimens taken, 168 of which were selected to be investigated by a third pathologist. Among these specimens only those (n=141) with a consensus diagnosis by at least two pathologists and p53 expression as additional marker were included in the analysis.

RESULTS

The median of normalised fluorescence intensity (ratio of delayed PpIX fluorescence intensity to immediate autofluorescence intensity) in non-dysplastic specialised intestinal metaplasia (0.51, 68% CI 0.09 to 1.92) and low grade dysplasia (1.89, 68% CI 0.55 to 3.92) differed significantly (p<0.005). Dysplasia was detected at a rate 2.8-fold higher compared with screening endoscopy despite taking fewer specimens. In addition, three early cancers were detected for the first time. Moreover, this method permitted differentiation of specialised intestinal metaplasia from junctional or gastric-fundic type epithelium (p<0.013).

CONCLUSIONS

For the first time it was possible to differentiate low grade dysplasia from non-dysplastic Barrett's mucosa during endoscopy based on delayed laser induced fluorescence endoscopy of PpIX. Furthermore, the method helps to detect specialised intestinal metaplasia in short Barrett's oesophagus.

[Oxygen-carrying solutions improve tissue oxygenation in striated skin muscle subjected to critical ischemia]

AIM

The aim of the present study was to investigate the effects of the oxygen-carrying hemoglobin solution DCLHb (diaspirin-crosslinked hemoglobin) on microvascular perfusion and tissue oxygenation in striated skin muscle after the induction of critical ischemia followed by reperfusion.

MATERIAL AND METHODS

Using intravital fluorescence microscopy the functional capillary density was analyzed in the striated skin muscle of Syrian golden hamsters before the induction of a 4-h period of ischemia and again after 0.5 h, 2 h and 24 h of reperfusion ( n=8 in each group). In other animals ( n=8 in each group), the identical protocol was applied to determine tissue oxygenation by means of the multi-wire surface electrode (MDO, Eschweiler, Kiel, Germany). Animals in the treatment group ( n=8) received a bolus infusion of 5 ml of DCLHb per kg of body wt. (10 g/dl; Baxter, Ill., USA) 15 min before reperfusion. Control animals ( n=8) received equivalent volumes of isotonic saline (Braun, Melsungen, Germany). RESULTS. Functional capillary density was dramatically reduced in control animals, while in DCLHb-treated animals significantly higher values were observed. Efficient restoration of tissue PO(2) was also seen in DCLHb-treated animals and not in control animals.

CONCLUSIONS

These results show that the oxygen-carrying solution DCLHb is significantly more efficient than the commonly used crystalloid solutions in restoration of tissue PO(2) after ischemia-reperfusion. The use of this solution therefore appears promising as a means of protecting the tissue put at risk by ischemia from reperfusion damage.

ACRC codes for a novel nuclear protein with unusual acidic repeat tract and maps to DYT3 (dystonia parkinsonism) critical interval in xq13.1

We searched for novel genes as candidates of X-linked dystonia parkinsonism (XDP) in the critical interval of Xq13.1 that harbors the disease locus (DYT3). A gene, ACRC (acidic repeat containing), was discovered by a combination of in silico and "wet" experiments. ACRC is composed of at least 12 exons and 11 introns. It is expressed in all tissues tested, including skeletal muscle, liver, kidney, pancreas, heart, lung, and brain. Highest levels of expression are found in skeletal muscle. The ACRC protein is characterized by a previously undescribed acidic repeat tract of 21 units of 8-10 amino acids. The N-terminal portion of the protein is highly acidic (pI=3.2), and the C-terminal region is basic (pI=10.2). There are nuclear localization signals in its C-terminal portion. Extensive mutation analysis of the transcribed region of the gene, including intron-exon boundaries and the 5' and 3' untranslated intervals, did not reveal a mutation in XDP patients. Exclusion of a mutation in the transcribed portion of this and all other known genes within the DYT3 critical interval suggests that XDP is most likely caused by a mutation in a regulatory region of a gene within the critical interval, or by a structural rearrangement.

Changes in the local blood and lymph microcirculation in response to direct mechanical trauma applied to leg: in vivo study in an animal model

BACKGROUND

The aim of this study was to investigate changes in the blood microcirculation of skin, subcutaneous tissue, and striated muscle, and the venous and lymphatic outflow from hind limb, after a standardized mechanical trauma.

METHODS

Trauma, defined as 50% of the minimal energy needed for tibia fracture (3.7 J/g), was applied to the leg of hairless mice. Intravenously injected fluorescein isothiocyanate-dextran 150 kDa and Rhodamine-6G were used for intra-vital fluorescence microscopy of blood vessels. Lymphatics were stained with fluorescein isothiocyanate-dextran injected into the footpad. A computer-assisted analysis system allowed measurement of the functional capillary density (FCD), vessel diameters, velocity of blood flow, and edema value expressed as extravasation index (EV). The percentage of slowly rolling and sticking leukocytes in postcapillary venules was estimated.

RESULTS

At the site of injury, trauma resulted in significant reduction of FCD in skin, subcutaneous tissue, and striated muscle. There were no significant differences in the vessel diameter (skin subcutaneous and muscle arterioles and venules, and superficial saphenous artery and vein) or velocity of blood flow (subcutaneous tissue and muscle venules). The EV increased significantly in muscle venules and was higher in muscles, subcutaneous tissue, and superficial saphenous veins than in controls (nonsignificantly). An increased percentage of slowly rolling and sticking leukocytes was noted in the superficial saphenous vein at the site of injury and proximal to it. The lymphatics remained patent, with faster visualization and increased summarized cross-sectional areas in traumatized extremities.

CONCLUSION

Early changes occurring in soft tissues in response to mechanical injury were characterized by reduction in FCD of skin and muscles, and less in subcutis; increased EV, reflecting leakage of macromolecules; increased percentage of slowly rolling and sticking leukocytes; maintenance of lymphatic vessel continuity; and increased lymph formation and flow rate.

Heparin protects local skin microcirculation in 210 minutes-long intravital microscopy observations under general anaesthesia

Prolonged immobilization of severely ill, bed-ridden patients results in formation of pressure ulcers following inappropriate tissue blood perfusion, and local activation of leukocyte - endothelial cell interactions (L/EC). Various treatment modalities were implemented to improve local microcirculation with controversial results. The aim of our study was to investigate the influence of heparin and buflomedil, drugs improving the microcirculation, on local skin blood perfusion using intravital fluorescent microscopy (IVM) technique.

MATERIAL AND METHODS

Experiments were carried out on 24 male hairless mice under inhalatory isofluran anaesthesia. Intravenous injection of FITC-dextran (150 kD, 5%) allowed to visualize capillaries during IVM, after immobilisation of hind limb, in an observation chamber. Observations were performed after i.v. injection of heparin (66 IU/kg b.w., n = 8) or buflomedil (6 mg/kg b.w., n = 8) 30, 120 and 210 minutes after chamber installation. Observations were recorded in 30 sec sequences on S-VHS tapes and evaluated using special software. Functional capillary density (FCD), defined as a total length of red cells perfused capillaries per observation field (expressed in cm/cm(2)), postcapillary venule diameters, and number of sticking leukocytes per 0.2 mm vessel length during 30 sec observation time, served as parameters of skin blood perfusion and activation of L/EC interactions.

RESULTS

A statistically significant decrease of FCD from 152.7 +/- 38.5 to 100.7 +/- 36.7 cm/cm (2) (p<0.05) was observed in control animals during 210 min lasting observation. Administration of heparin prevented decrease in FCD occurring in control animals during intravital microscopy, whereas buflomedil was found ineffective. Both drugs induced a nonsignificant reduction in the number of sticking leukocytes, whereas no changes in postcapillary venule diameters could be observed.

CONCLUSION

The results suggest a protective effect of heparin in clinical therapeutic doses against impairment of skin perfusion during IVM. This observation may justify a trial on the effects of heparin in prevention of development of pressure ulcers.

Protoporphyrin IX occurs naturally in colorectal cancers and their metastases

Colorectal cancers exhibit a red fluorescence. The nature of the responsible fluorophore and its eventual diagnostic potential were investigated. Thirty-three consecutive colorectal resection specimen, 32 of which with histologically confirmed cancer, and a total of 1053 palpable mesenteric nodes were fluorimetrically characterized ex vivo. Furthermore, frozen material from 28 patients was analyzed, selected for the availability of primary tumor material and metastatic tissue, e.g., lymphatic and liver metastases from the same patient. Biochemical characterization was carried out through chemical extraction and reversed phase high-performance liquid chromatography. The fluorescence spectra of tissues, tissue extracts, and standard solutions of porphyrins were determined using a pulsed solid-state laser system for excitation and an imaging polychromator, together with an intensified CCD camera for time-delayed observation. Protoporphyrin IX (PpIX) was identified as the predominant fluorophore in primary tumors and their metastases. The fluorophore occurred in the absence of necrosis and in sterile locations. In untreated cases (n = 24), PpIX fluorescence discriminates metastatically involved lymph nodes from all other palpable nodes with a sensitivity of 62% at a specificity of 78% (P < 0.0001). After neoadjuvant treatment of rectal cancer, the PpIX fluorescence level of the primary tumors was reduced and a discrimination of lymph nodes based on PpIX-fluorescence was impossible. We conclude that colorectal cancer metastases accumulate diagnostic levels of endogenous PpIX as a result of a tumor-specific metabolic alteration.

A new chamber technique for intravital microscopic observations in the different soft tissue layers of mouse hindleg

BACKGROUND

A newly developed observation chamber has been designed for comfortable limb immobilization during intravital microscopic analysis, which permits direct, repeated, long-lasting observations of the microcirculation in the various hindleg soft tissues.

METHODS

Experiments were performed under inhalation isoflurane/nitrous oxide anesthesia. Intravenously injected fluorescein isothiocyanate (FITC)-dextran (M, 150,000) and Rhodamine 6G (Sigma, St. Louis, MO) allowed for visualization of both microcirculatory phenomena in arterioles, capillaries, and venules and macrocirculatory structures as superficial saphenous artery and vein. Skin microcirculation analysis was performed from the epidermal side (group A, n = 7), whereas observation of deeper situated tissues was performed after oval skin excision on the medial surface of the tibial area (group B, n = 7). FITC-dextran (M, 150,000; group C, n = 8) injected into the foot pad permitted visualization of venous, arterial, and accompanying lymphatic vessels. With the aid of a computer-assisted microcirculation analysis system, functional capillary density, vessel diameter, edema formation, and leukocyte-endothelial cell interactions were evaluated. The ratio of rolling leukocytes, given as percentage of all leukocytes passing the vessel segment during a 30-second observation interval, and the number of sticking leukocytes per square millimeter of endothelial surface were determined.

RESULTS

This new model allows the analysis of the complex in vivo changes of macro- and microcirculatory parameters in the different (venous, arterial, lymphatic) vessels of the covering tissues (skin and muscle) of the mouse hindleg.

CONCLUSION

The potential applications of this technique include the study of mechanical trauma, ischemia-reperfusion injury, and tissue compression mimicking both acute and prolonged venous stasis on both the microcirculatory and macrocirculatory levels in the different tissue compartments.

Compatibility of different colloid plasma expanders with perflubron emulsion: an intravital microscopic study in the hamster

BACKGROUND

Perfluorocarbon-based oxygen carriers have been proposed as an adjunct to autologous blood conservation techniques during elective surgery. To date, the effects of perfluorocarbon emulsions at the microcirculatory level have not been studied extensively. In this study the effects of perflubron emulsion on the microcirculation after acute normovolemic hemodilution (ANH) were investigated using different colloid plasma expanders.

METHODS

The dorsal skin fold chamber model and intravital fluorescence microscopy were used for analysis of the microcirculation in the thin striated skin muscle of conscious hamsters (body weight, 40-60 g). Measurements of microvascular perfusion and leukocyte adhesion (n = 6 animals per experimental group) were made before and at 10, 30, and 60 min after ANH (to hematocrit 0.3) with either 6% hydroxyethyl starch 200/0.6 (HES), 3.5% gelatin, 5% human serum albumin (HSA), or 6% dextran 60 (DX-60) followed by intravenous injection of 3 ml/kg body weight of a 60% weight/volume perfluorocarbon emulsion based on perflubron (perfluorooctyl bromide) emulsified with egg yolk lecithin.

RESULTS

Acute normovolemic hemodilution with HES, gelatin, or HSA followed by injection of perflubron emulsion elicited no alterations of local microvascular perfusion or leukocyte-endothelium interaction as assessed in arterioles and postcapillary venules. However, ANH with DX-60 followed by injection of perflubron emulsion led to a significant reduction of erythrocyte velocity in postcapillary venules and an increase in venular leukocyte sticking that was never observed with DX-60 alone.

CONCLUSIONS

Hydroxyethyl starch, gelatin, and HSA are compatible with perflubron emulsion in the setting of ANH. Only DX-60 appeared to be incompatible with perflubron emulsion, as evidenced by impairment of capillary perfusion.

Effects of the phlebotropic drug Daflon 500 mg on postischemic reperfusion injury in striated skin muscle: a histomorphologic study in the hamster

The objective of this study was to investigate the effects of the purified, micronized, flavonoid fraction Daflon 500 mg (S 5682, 90% diosmin and 10% hesperidin) on tissue damage and leukocyte emigration in striated skin muscle after ischemia-reperfusion, as assessed by histomorphometric analysis. The experimental model used was the transparent dorsal skin fold chamber in the awake Syrian golden hamster. Sixty-four animals were randomly allotted to two treatment groups and time points of investigation. Animals were fed with 30 mg kg(-1) body weight Daflon 500 mg (n = 32) or its vehicle, 5% Arabic gum solution (n = 32), as control 8 hours before ischemia. Before induction of a tourniquet ischemia of 4 hours' duration and at 0.5, 2, and 24 hours of reperfusion, tissue sections were preserved for light and electron microscopic analysis (n = seven or eight animals per time point). The number of intravascular and extravascular leukocytes was determined by light microscopic analysis of esterase-positive leukocytes. For quantitative analysis of ischemia-induced endothelial cell damage, the endothelial thickness of capillaries was calculated by a computer-assisted imaging system, whereas the ischemic tissue damage was assessed by means of a score system (grade 0-3) by an independent investigator. The number of emigrated leukocytes was significantly reduced in Daflon 500 mg-treated animals compared with numbers found in control animals. The histomorphologic muscle fiber damage increased after reperfusion in both groups but was significantly reduced in the Daflon 500 mg-treated animals 2 and 24 hours after reperfusion. These results suggest that the emigration of leukocytes plays an important role in the development of postischemic reperfusion injury of striated skin muscle.

Effects of the phlebotropic drug Daflon 500 mg on postischemic microvascular disturbances in striated skin muscle: an intravital microscopic study in the hamster

The objective of this study was to investigate the effects of the micronized purified flavonoid fraction Daflon 500 mg (90% diosmin and 10% hesperidin) on I/R-induced microvascular leukocyte-endothelium interaction and leakage of the high molecular weight plasma tracer FITC-dextran (relative molecular mass, 150 kd) as assessed in the striated skin muscle of the dorsal skin fold chamber model in the hamster. Intravital fluorescence microscopy was used for analysis of microvascular perfusion, leukocyte-endothelium interaction, and macromolecular leakage of FITC-dextran 150 kd in the striated skin muscle of the hamster. A tourniquet ischemia of 4 hours' duration was induced followed by reperfusion. Animals were treated with an oral administration of Daflon 500 mg (n = six) or its vehicle (5% Arabic gum solution, n = six) for 8 days at a daily dose of 30 mg/kg body weight. Measurements in the microcirculation were made before the 8-day feeding protocol before induction of ischemia and at 0.5, 2, and 24 hours of reperfusion. In the absence of I/R, no differences in microvascular perfusion, leukocyte-endothelium interaction, and macromolecular leakage were found in Daflon 500 mg and vehicle-treated control animals before and after administration of the drugs. Induction of ischemia and reperfusion, however, elicited a significant increase in venular leukocyte rolling and sticking in vehicle-treated animals, which was accompanied by enhancement of leakage of FITC-dextran 150 kd into the perivascular tissue. Treatment with Daflon 500 mg had no effect on postischemic leukocyte rolling and sticking, and macromolecular leakage of FITC-dextran 150 kd from arterioles and postcapillary venules was significantly reduced. These data indicate that Daflon 500 mg preserves the endothelial barrier function of striated skin muscle arterioles and venules after I/R, which appears to be independent of an action on postischemic intravascular leukocyte rolling and sticking.

Refined linkage disequilibrium and physical mapping of the gene locus for X-linked dystonia-parkinsonism (DYT3)

X-linked dystonia-parkinsonism (XDP) is a recessive disorder characterized by generalized dystonia with some patients exhibiting parkinsonism. The disease gene, DYT3, is located between DXS453 (DXS993) and DXS559, and strongest linkage disequilibrium is found distal to DXS7117 and proximal to DXS559. We have isolated and analyzed four novel polymorphic markers between DXS7117 and DXS559 and, by haplotype analysis, have narrowed the candidate interval to <350 kb. A sequence-ready contig of 700 kb has been constructed spanning DXS7117 to DXS559 and is composed of 35 PACs, BACs, and cosmids. Nine genes and novel ESTs have been mapped into this contig, and mutations in the coding regions and intron-exon borders of two genes have been excluded as the cause of XDP. Several of the other genes and ESTs located within the contig code for proteins implicated in normal brain development and function and are candidates for DYT3.

DNA analysis of Huntington's disease: five years of experience in Germany, Austria, and Switzerland

OBJECTIVE

To review the direct DNA testing for Huntington's disease (HD) in Germany, Switzerland, and Austria from 1993 to 1997, and to analyze the population with regard to age structure, gender, and family history.

METHODS

Twelve laboratories (nine in Germany, two in Austria, and one in Switzerland) recorded data pertaining to repeat number, gender, age at molecular diagnosis, and family history of probands. The molecular test was categorized as either diagnostic (for symptomatic individuals), presymptomatic (for individuals at risk), and prenatal (for pregnancies at risk).

RESULTS

A total of 3,090 HD patients, 992 individuals at risk, and 24 fetuses were investigated using DNA analysis. The clinical diagnosis was confirmed in 65.6% of patients. A total of 38.5% of individuals at risk inherited an expanded CAG repeat. The female-to-male ratio showed a distinct predominance of women both in the diagnostic and presymptomatic groups. Of the fetuses tested, six were carriers of an expanded CAG repeat. Two pregnancies were interrupted; one pregnancy was not. No information about the parents' decision was obtained for the remaining three pregnancies.

CONCLUSIONS

Approximately 20% of the estimated 10,000 HD patients living in Germany, Switzerland, and Austria have been identified by DNA analysis (total population, approximately 100 million; incidence of HD, 1:10,000). Assuming a ratio of HD patients to individuals at risk of 1:3, approximately 30,000 individuals are, in principle, eligible for a presymptomatic test. Less than 3 to 4% of individuals at risk have requested a presymptomatic test. This shows that the assumed enormous request of predictive testing has not occurred. More surprisingly, prenatal diagnoses were found to be rare.

[A new experimental model for repetitive osseous blood supply measurement]

The aim of this study was to establish a novel model permitting repetitive analysis of osseous perfusion over a period of 33 days using the fluorescent microsphere technique. After implantation of two port systems into the right and left carotid artery in New Zealand rabbits (n = 3), fluorescent microspheres were injected into the left ventricle, while blood samples for reference probes were taken from the descending aorta. Using seven different fluorescently labeled microspheres, injections were repeatedly performed starting 3 days after implantation (t = 0) at days 1, 3, 5, 12, 19, 26, and 33. Osseous blood flow was semiquantitatively analyzed by counting the number of trapped microspheres within the bone sections performed through the distal femur condyle (n = 8) using a fluorescence microscope. Over the entire observation period of 33 days, intraindividual variance in the number of trapped microspheres was low while there were marked interindividual differences between animals. The mean osseous perfusion in the three animals evaluated so far remained constant over the observation period of 33 days. The present model is the first to allow repetitive analysis of osseous perfusion over an observation period of 33 days. Using this model, the role of regional osseous perfusion can be studied under conditions such as impaired bone healing following radiotherapy- and/or chemotherapy, implantation of biomaterials, and transplantation of bone.

Attenuation of postischemic reperfusion injury in striated skin muscle by diaspirin-cross-linked Hb

Hemoglobin-based oxygen carriers have been suggested to enhance the formation of oxygen free radicals, especially under conditions of ischemia-reperfusion (I/R), in which activation and adhesion of leukocytes play a pivotal role for propagation of reperfusion injury. This study investigates the effects of the hemoglobin-based oxygen carrier diaspirin-cross-linked hemoglobin (DCLHb) in an I/R model of hamster striated skin muscle. The dorsal skinfold chamber model in the awake Syrian golden hamster was used for analysis of the microcirculation and local tissue PO2 in striated skin muscle utilizing the technique of intravital fluorescence microscopy and a multiwire platinum surface (Clark type) electrode. Measurements were made before 4 h of pressure-induced ischemia and at 0.5, 2, and 24 h of reperfusion. Animals were treated with 5 ml/kg body wt of either 10% DCLHb (n = 8), 6% Dextran 60 (Dx-60; 60 kDa, n = 8), or 0.9% NaCl (n = 7), which was given intravenously 15 min before reperfusion. In animals treated with DCLHb or Dx-60, a significant decrease of leukocytes rolling along and sticking in postcapillary venules, associated with a recovery of functional capillary density and red blood cell velocity, was observed compared with saline-treated controls. In the early reperfusion period (0.5 h), DCLHb and Dx-60 efficiently restored local tissue PO2, whereas tissue PO2 decreased from 18.3 +/- 1.9 to 15.3 +/- 5.3 mmHg in 0.9% NaCl-treated animals. Electron microscopic analysis of the postischemic tissue at 24 h of reperfusion revealed markedly reduced tissue damage in animals treated with DCLHb compared with Dx-60 or isotonic saline. These results indicate that DCLHb attenuates postischemic reperfusion injury of striated skin muscle, presumably through alterations of leukocyte-endothelial cell interactions.

Impact of brain death on hormonal homeostasis and hepatic microcirculation of transplant organ donors

To elucidate the pathophysiological mechanisms involved in the deterioration of hepatic graft viability in brain-dead organ donors, the impact of brain death on hepatic microcirculation was investigated with respect to hormonal homeostasis and graft viability. Rats were assigned to two groups: group I (n = 6) served as sham controls, and in group II (n = 6), brain death was induced through insufflation of an intracranial balloon. Mean arterial pressure was elevated significantly within 5 min after the induction of brain death and then decreased significantly to below the control value. Urine osmolality was significantly lower and serum osmolality significantly higher than the control values. Antidiuretic hormone level was significantly lower than the control value. Bile secretion also decreased significantly. Furthermore, in group II there were significantly higher numbers of nonperfused sinusoids (15.9% vs 6.2% in group I), and sinusoidal stagnant and postsinusoidal venular adherent leukocytes (53.9/lobule and 258.6/mm2 versus 25.2/lobule and 124.8/mm2 in group I, respectively). In summary, sinusoidal perfusion is compromised after brain death, possibly, in part, through an increased leukocyte activation and accumulation in the hepatic microvasculature, leading to the deterioration of hepatic function.

A novel model for the study of synovial microcirculation in the mouse knee joint in vivo

A novel model for the investigation of the microcirculation in synovial tissue of the mouse knee joint is presented. The mouse knee joint was exposed on a specially designed plexiglass stage with a slight flexion. After partial resection of the skin, the patella tendon was cut transversally, which allowed for visualization of the "Hoffa's fatty body", an intraarticular fatty tissue containing synovial cells on the interior surface of the joint. An intravital fluorescence microscope was adjusted to observe the microcirculation of this intraarticular synovial tissue without opening of the joint capsula. For staining of the plasma, fluorescein isothiocyanate (FITC)-dextran was used, and for the staining of leukocytes rhodamine 6G was used. The tissue investigated presents with a high-density honeycomb-like capillary network, containing some postcapillary venules and a few arterioles. The following parameters were assessed off-line using a computer-assisted microcirculation analysis system: flow and diameter of arterioles and postcapillary venules, as well as functional capillary density. Moreover, leukocyte-endothelial cell interaction was quantified by counting the number of rolling cells and cells adhering to the endothelium in postcapillary venules. As an indication of endothelial leakage, macromolecular extravasation was also assessed. To validate the model, we investigated these parameters at three time points during an observation period of 60 min. There was no change in functional capillary density, nor in vessel diameter after 60 min of observation. Moreover, there was neither a change in the number of rolling cells, nor in the number of cells adhering to the endothelium nor in extravasation of FITC-dextran, thus indicating the stability of the preparation. The new model allows the quantitative analysis of the intraarticular microcirculation of the synovial fatty tissue in vivo. It provides insight into the dynamics of synovial microcirculation and leukocyte-endothelial cell interaction in acute or chronic joint inflammation.

Direct-to-video holographic 3-D imaging using photorefractive multiple quantum well devices: errata

Due to an oversight during the revision process, one of the authors was not mentioned in this paper. The author list should read: R. Jones, M. Tziraki, D. Parsons Karavassilis, P. M. W. French, K. M. Kwolek, D. D. Nolte and M. R. Melloch.

Direct-to-video holographic 3-D imaging using photorefractive multiple quantum well devices

Customised photorefractive quantum well devices have been developed for real-time video acquisition of coherence-gated, three-dimensional images. Holographic imaging with direct video capture has been demonstrated. The technique has been applied to 3-D imaging through turbid media with 50 mm transverse and 60 mm depth resolution being achieved using near infrared light through a phantom of 13 mean free paths scattering depth. Spectrally-resolved holographic imaging has also been demonstrated.

Transient dynamics during two-wave mixing in photorefractive quantum well diodes using moving gratings

The temporal dynamics of photorefractive and absorptive gains during two-wave mixing in Stark geometry photorefractive quantum wells are investigated using moving gratings to break the symmetry of the photorefractive diodes to achieve nonreciprocal energy transfer between two coherent laser beams.

Effects of Daflon 500mg on postischemic macromolecular leak syndrome in striated skin muscle of the hamster

We have recently shown that the purified micronized flavonoid fraction (90% diosmin and 10% hesperidin) Daflon 500 mg attenuates reperfusion injury in the striated skin muscle of the hamster. Herein, we report on the action of Daflon 500 mg on postischemic macromolecular leakage of FITC-dextran 150 kD provoked by tourniquet ischemia. Intravital fluorescence microscopy was used for analysis of macromolecular leakage in the microcirculation model of the hamster. A tourniquet ischemia of 4 h duration was induced followed by reperfusion. Animals were treated by gavage of Daflon 500 mg (n = 6) for 8 days at a daily dose of 30 mg kg(-1) body weight. Control animals received equivalent volumes of the vehicle (5% Arabic gum solution, n = 6). Measurements of the microcirculatory parameters were made before induction of ischemia and at 0.5, 2 and 24 h of reperfusion. After induction of ischemia, macromolecular leakage from postcapillary venules was significantly enhanced in vehicle-treated animals. Treatment with Daflon 500 mg significantly attenuated macromolecular leakage of FITC-dextran 150 kD. Preliminary data from a histomorphometric analysis (n = 3/experimental group) indicated that the number of emigrated (extravascular) leukocytes after ischemia reperfusion was markedly reduced in Daflon 500 mg-treated animals as compared to controls. These data indicate that Daflon 500 mg prevents leakage of the macromolecular tracer FITC-dextran 150 kD from postcapillary venules after postischemic reperfusion, presumably through an inhibitory action on the emigration of activated leukocytes.

[Effect of adenosine on intravascular accumulation of leukocytes and tissue damage in striated muscle in endotoxemia]

Under the experimental conditions of endotoxinemia, the therapeutic use of an intravenous infusion of adenosine (110 micrograms x kg-1 x min-1) has been investigated in the microcirculation model of the BALB/c mouse. Injection of S. abortus-equi endotoxin (2 mg x kg-1 body wt. i.v.) elicited a significant increase of sticking leukocytes in postcapillary venules of striated skin muscle, which was associated with a swelling of microvascular endothelium and striated skin muscle. Infusion of adenosine effectively attenuated the endotoxin induced enhancement of leukocyte sticking and preserved microvascular endothelial and striated muscle integrity. These results imply the use of adenosine as therapeutic concept during endotoxinemia.