Influence of C1-esterase inhibitor on tissue oxygenation of jejunal mucosa during endotoxemia

BACKGROUND

The complement system has been shown to play an important role in the pathogenesis of microcirculatory disturbances in trauma and sepsis. The intestinal mucosa is the most susceptible portion of the gut to impaired perfusion and oxygen delivery. The objective of this study was to investigate the effects of C1-esterase inhibitor (C1-INH) on arterial oxygenation (PaO2) and tissue oxygenation (PtiO2) of jejunal mucosa during endotoxemia.

METHODS

Eighteen anesthetized and ventilated rats were laparotomized and a jejunal portion was exteriorized and fixed on a plexiglass stage. The jejunum was punctured and a Clark type microcatheter PO2 probe and a micro thermocouple were placed on the mucosa in order to measure PtiO2. The animals were randomly assigned to receive one of the three treatments: infusion of Escherichia coli lipopolysaccharides (LPS) without C1-INH pretreatment (LPS group); or infusion of LPS with C1-INH pretreatment (C1-INH group); the control group (n = 6) without treatment of either C1-INH or LPS. The mean arterial pressure (MAP), heart rate (HR), PaO2 and PtiO2 were measured at baseline, 60 and 120 min after induction of endotoxemia.

RESULTS

Hemodynamic parameters (MAP, HR) in all the three groups showed no significant changes during the study period. PaO2 significantly decreased in the LPS group. This decrease could be attenuated by pretreatment with C1-INH. The mucosal PtiO2 of the jejunum in the control group remained stable. It significantly decreased in the LPS and in the C1-INH groups without showing a significant difference after 120 min of endotoxemia.

CONCLUSIONS

Pretreatment with C1-INH was able to diminish a decrease in PaO2 during endotoxemia, indicating that pulmonary injury was attenuated. Endotoxin-induced tissue hypoxia of the intestinal mucosa could not be prevented suggesting a minor involvement of complement activation in this pathophysiological process.

Unusual presentations of neuroborreliosis (Lyme disease) in childhood

Two children with atypical neuroborreliosis (cranial polyneuritis and acute transverse myelitis) are presented. The diagnosis was confirmed by the determination of specific antibodies against Borrelia burgdorferi in both serum and CSF. Neuroimaging findings were nonspecific, indicating, however, that neuroborreliosis should be included in the differential diagnosis of cases with cranial polyneuritis and acute transverse myelitis in childhood.

Effect of propentofylline on hippocampal brain energy state and amyloid precursor protein concentration in a rat model of cerebral hypoperfusion

An animal model of graded cerebral hypoperfusion achieved by way of 2- and 4-brain vessel occlusion (vo) was used to test the effect of chronic propentofylline (PPF) administration on hippocampal energy state and amyloid precursor protein (APP) concentration. For this purpose, forty adult rats were subjected to stepwise and permanent 2 vo and 4 vo and PPF in a dose of 25 mg/day per kilogram body weight was continuously administered intraperitoneally for 1 week or 3 weeks, respectively. During the final steady-state experiment arterial blood parameters and blood gases (mean arterial blood pressure, PO2, pCO2, pH, hematocrit, hemoglobin, body temperature) were measured. Brain tissue concentrations of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine were measured in rat hippocampus by high-pressure liquid chromatography (HPLC) analysis; APP concentration was determined using Western blot techniques. In adult rat brain, long-term PPF treatment induced a striking increase in hippocampal ATP concentration which was paralleled by an enhancement of the ATP/ADP-ratio. Specifically, after 2 vo with 1 week of PPF treatment the ATP concentration in hippocampus was enhanced by 18% when compared with 2 vo without PPF treatment, whereas after 3 weeks PPF administration with 4 vo the concentration of ATP was enhanced by 31%. Furthermore, PPF reduced the tissue concentration of adenosine from 17.75 +/- 2.79 to 8.83 +/- 3.68 pmol/mg wet weight during 4 vo if compared with animals without PPF. In addition, the APP concentration was enhanced by 35% after 1 week PPF administration when compared with non PPF treated animals. In summary, the results demonstrated that chronic administration of PPF induced an enhancement in ATP concentration in adult rat hippocampus under conditions of long-term brain vessel occlusion. Interestingly, 1 week PPF seems to have a stimulating effect on APP which may act neuroprotectively. Thus, PPF may protect hippocampal neurons from chronic ischemic damage. In conclusion, PPF may have some beneficial effects and could be used in the treatment of patients with chronic cerebrovascular disorders or neurodegenerative diseases such as vascular dementia.

Components of after-hyperpolarization in magnocellular neurones of the rat supraoptic nucleus in vitro

1. The pharmacological sensitivity of hyperpolarizing components of spike train after-potentials was examined in sixty-one magnocellular neurones of the rat supraoptic nucleus using intracellular recording techniques in a brain slice preparation. 2. In 26 % of all neurones a slow after-hyperpolarization (AHP) was observed in addition to a fast AHP. In 31 % of all neurones a depolarizing after-potential (DAP) was observed. 3. The fast AHP was blocked by apamin whereas the slow AHP was blocked by charybdotoxin (ChTX). The DAP was enhanced by ChTX or a DAP was unmasked if not present during the control period. 4. Low concentrations of TEA (0.15-1.5 mM) induced effects on the slow AHP and the DAP essentially resembling those of ChTX. The same was true for the effects of CoCl2 (1 mM). 5. Spike train after-potentials were not affected by either iberiotoxin (IbTX), a selective high-conductance potassium (BK) channel antagonist, or margatoxin (MgTX), a Kv1.3 alpha-subunit antagonist. 6. Kv1.3 alpha-subunit immunohistochemistry revealed that these units are not expressed in the somato-dendritic region of supraoptic neurones. 7. The effects of ChTX, IbTX, MgTX, TEA, CoCl2 and CdCl2 on spike train after-potentials are interpreted in terms of an induction of the slow AHP by the activation of calcium-dependent potassium channels of intermediate single channel conductance (IK channels). 8. The results suggest that at least the majority of supraoptic magnocellular neurones share the capability of generating both a slow AHP and a DAP. The slow AHP may act to control the expression of the DAP, thus regulating the excitability of magnocellular neurones. The interaction of the slow AHP and the DAP may be important for the control of phasic discharge.

Role of antioxidants in gastric mucosal damage induced by indomethacin in rats

Reactive oxygen species play a role in the formation of gastric lesions induced by nonsteroidal antiinflammatory drugs. The present study was undertaken to determine whether endogenous antioxidants in gastric mucosa can protect it against the damaging effects of oxygen free radicals. This study examine oxygen free radical production (superoxide anions and hydrogen peroxide), gastric mucosa antioxidant defense mechanisms (glutathione, catalase, superoxide dismutase), the lesion-inducing effects of the generated oxygen free radicals (vascular permeability, lipid peroxidation) and gastric ulceration in rats treated orally with indomethacin at 10 mg/kg at 2 and 6 h after drug administration. Two hours after administration of the antiinflammatory drug, there was a sharp increase in production of oxygen free radicals in the gastric mucosa with no alteration in other parameters examined. Six hours after indomethacin administration the production of oxygen free radicals returned to basal levels, but there was a high degree of gastric ulceration and a significant increase in lipid peroxidation and vascular permeability together with decreases of 45% in glutathione concentration and 30% in catalase relative to the control group. These results suggest that like plasma, the gastric mucosa has an antioxidant capacity and only when this capacity is exhausted are the lesive effects of the oxygen free radicals manifested.

A decade of caring for drug users entirely within general practice

BACKGROUND

The government encourages general practitioners (GPs) to become involved in caring for drug users. However, in some areas of the country, including Bedford, secondary care support is inadequate. GPs in these areas have to decide how to cope with such patients entirely within general practice.

AIM

To assess the characteristics and quality of care given without secondary care support to drug users by one practice in Bedford over a decade.

METHOD

A search was made of the practice computer for all patients with a problem title of 'addiction drug' between 1986 and 1995. The age, sex, social characteristics, and drug history were recorded.

RESULTS

One hundred and ninety-two patients were found, of which 155 took part in the practice programme; i.e. they consulted more than three times. Forty-three patients (37%) who took part and were prescribed Methadone were prescribed this drug as ampoules. Sixty-three patients (40.6%) who took part in the programme stopped using drugs. Thirty-two (33.6%) of the Methadone users became abstinent. A higher proportion of women (13-48%) than men (19-27.7%) stopped using Methadone (P = 0.019). Among patients who had a stable lifestyle, a higher proportion had been prescribed ampoules than mixture (22 out of 28: 78.6%; P = 0.001). Similarly, of those who had a job, eight out of 11 (72%; P = 0.037) had been prescribed methadone ampoules. Two-thirds of all patients prescribed amphetamines stopped using drugs.

CONCLUSION

Long-term care of drug users entirely within general practice is feasible. Among those prescribed methadone ampoules, a higher than average proportion had stable lifestyles and had a stable job.

[Premedication and preoperative fasting in pediatric anesthesia. Results of a survey]

This study evaluates the current practice of premedication and preoperative fasting in pediatric anaesthesia in Germany. A total of 90 questionnaires were mailed to randomly selected hospitals with departments or sections of anaesthesiology and pediatric surgery. 71 questionnaires were returned and analysed (reply rate 79%). 60% of the responding hospitals start premedication between the ages of 3 and 12 months and 32% between 1 and 2 years of age. Premedication ist most often given orally (64%), followed by rectal (29%) and intranasal (3%) routes. Midazolam is used by 96% of the respondents as the primary sedative premedication. Alternatively, promethazine and chloraldhydrate are most frequently used. Anticholinergic drugs are given routinely by 21% of the respondents. For the apprehensive child intramuscular ketamine is most often used (33%), followed by intranasal midazolam (22%), rectal midazolam (19%) and rectal thiopentone or methohexitone (13%). For children less than 1 year of age 63% of the hospitals restrict clear liquids 2 hours and 34% 3 or 4 hours before anaesthesia. 64% of the respondents require abstinence from milk for 4 hours and 30% for 6 hours prior to surgery. For children older than one year of age fasting period requirements for clear liquids were 2 hours (34%), 3 hours (27%), 4 hours (30%) and 6 hours (9%). For children over 1 year of age the majority allow solid food or milk up to 6 hours prior to anaesthesia (68% and 63%, respectively). The survey shows that premedication is started during the first two years of age by nearly all responding hospitals. Oral or rectal midazolam is the most frequently used premedication regimen. Preoperative fasting guidelines vary.

Lasting cytotoxic edema as an indicator of irreversible brain damage: a case of neonatal stroke

We describe a case of neonatal stroke in the territory of the left middle cerebral artery. Although the ischemic lesion appeared rather homogeneously hyperintense on T2-weighted MR images, corresponding diffusion-weighted images clearly delineated two separate zones of different cellular swelling and, thus, different prognoses. Lasting cytotoxic edema heralded infarction. We believe that the different rates of disintegration of neurons and glial cells may have caused the change from intracellular to interstitial volume fraction during the evolution of edema.

Dopexamine attenuates endotoxin-induced microcirculatory changes in rat mesentery: role of beta2 adrenoceptors

OBJECTIVE

To investigate the influence of dopexamine on endotoxin-induced leukocyte adherence and on vascular permeability in postcapillary venules of rat mesentery.

DESIGN

Randomized, controlled trial.

SETTING

Experimental laboratory.

SUBJECTS

Twenty-seven male Wistar rats, weighing 250 to 350 g.

INTERVENTIONS

Rats received one of three treatments: a) infusion of Escherichia coli endotoxin without dopexamine pretreatment; b) infusion of endotoxin with dopexamine pretreatment; or c) infusion of endotoxin after pretreatment with dopexamine and ICI 118,551, a selective beta2-receptor antagonist.

MEASUREMENTS AND MAIN RESULTS

Leukocyte adherence, red blood cell velocity, and vessel diameters in postcapillary venules were evaluated using in vivo videomicroscopy. Vascular permeability was determined by measuring the extravasation of fluorescence-labeled albumin. Venular wall shear rate was calculated from red cell velocity and vessel diameter. Dopexamine attenuated both the increase in leukocyte adherence and vascular permeability during endotoxemia. The attenuating effect on leukocyte adherence could not be antagonized by the beta2-adrenoceptor antagonist. However, the attenuating effect on vascular permeability was antagonized by ICI 118,551. Dopexamine prevented a decrease in venular wall shear rate during endotoxemia. This effect was not influenced by ICI 118,551.

CONCLUSIONS

Dopexamine attenuates endotoxin-induced microcirculatory disturbances in rat mesentery. The attenuating effect on vascular permeability is a beta2-adrenoceptor-mediated process, whereas the beta2-adrenoceptor actions of dopexamine play no significant role in attenuating leukocyte adherence.

Cardiac output measurement by transpulmonary versus conventional thermodilution technique in intensive care patients after coronary artery bypass grafting

OBJECTIVE

The aim of the present study was to evaluate the correlation, accuracy, and precision of transpulmonary thermodilution cardiac output (CO) measurement. For this purpose, this technique was compared with the clinical gold standard, the CO measurement by pulmonary artery catheter in patients after coronary artery bypass grafting (CABG).

DESIGN

A prospective clinical study.

SETTING

A university medical center.

PARTICIPANTS

Seventy-five patients in an intensive care unit (ICU) after CABG.

INTERVENTIONS

Standard (SCO) and transpulmonary thermodilution CO measurement (TPCO) measurements were simultaneously performed in triplicate by central venous injection of cooled saline solution. All variables were recorded at five different time points of measurement during weaning from mechanical ventilation.

MEASUREMENTS AND MAIN RESULTS

CO measurements yielded 375 data pairs. SCO ranged from 2.0 to 10.2 L/min, and TPCO from 1.3 to 10.6 L/min. During the entire observation period, TPCO measurements tended to yield relatively high values, whereas SCO measurements resulted in lower values. Correlation between TPCO and SCO measurements was significant (r = 0.73; p < 0.05), accompanied by an accuracy with a bias of 0.456 L/min (7.3%) and a precision of 1.156 L/min (18.5%).

CONCLUSION

In most patients, TPCO measurement will not replace the conventional technique by pulmonary artery catheter, but in some patients it offers an attractive, reliable, and safe method to determine CO.

Multiple sclerosis in Móstoles, central Spain

OBJECTIVES

Until relatively recently southern Europe was regarded as having a medium to low multiple sclerosis prevalence, of about 20 or less per 100,000. However, recent studies in Sardinia, Sicily, continental Italy, Cyprus and Spain have yielded higher MS prevalence rates, between 32 and 102.6 per 100,000. We present the results of a prevalence study of MS in the municipality of M6stoles, central Spain.

MATERIAL AND METHODS

To ascertain the prevalence of multiple sclerosis in M6stoles (195,979 inhabitants), an intensive study was undertaken using several sources of information. We used the Poser criteria in diagnosis.

RESULTS

There were 85 patients (53 women and 32 men) classified as definite or probable, prevalence 43.4/100,000 (95% CI, 34.7 to 53.7). The incidence rate was 3.8/100,000/year (95% CI, 2.7 to 5.3) in the last 5 years. Mean age on prevalence day was 38.8+/-10.9 years. Mean age at onset was 31.7+/-9.3 years. Mean interval between initial symptoms and diagnosis was 1.7 years. Mean duration of disease was 7.6+/-6.1 years. Overall, 70.6% had a relapsing-remitting course, 18.8% had a primary progressive and 10.5% had a secondary progressive. Mean EDSS score was 2.7+/-1.9.

CONCLUSION

The M6stoles study confirms the conclusions of previous smaller population studies that Spain is a moderately high or medium MS risk zone.

An activity in rat tissues that modifies nitrotyrosine-containing proteins

Homogenates from rat spleen and lung could modify nitrotyrosine-containing BSA. With incubation, nitrotyrosine-containing BSA lost its epitope to a monoclonal antibody that selectively recognized nitrotyrosine-containing proteins. In the presence of protease inhibitors, the loss of the nitrotyrosine epitope occurred without protein degradation and hydrolysis. This activity was found in supernatant but not particulate fractions of spleen homogenates. The factor was heat labile, was sensitive to trypsin treatment, and was retained after passage through a membrane with a 10-kDa retention. The activity was time- and protein-concentration dependent. The activity increased about 2-fold in spleen extracts with endotoxin (bacterial lipopolysaccharide) treatment of animals, suggesting that the activity is inducible or regulatable. Other nitrotyrosine-containing proteins also served as substrates, while free nitrotyrosine and some endogenous nitrotyrosine-containing proteins in tissue extracts were poor substrates. Although the product and possible cofactors for this reaction have not yet been identified, this activity may be a "nitrotyrosine denitrase" that reverses protein nitration and, thus, decreases peroxynitrite toxicity. This activity was not observed in homogenates from rat liver or kidney, suggesting that there may also be some tissue specificity for the apparent denitrase activity.

Influence of N-acetylcysteine treatment on endotoxin-induced microcirculatory disturbances

OBJECTIVES

To determine the influence of N-acetylcysteine (NAC) in a treatment model, its effects on endotoxin-induced leukocyte-endothelial cell adhesion, vascular leakage, and venular microhemodynamics in postcapillary venules of rat mesentery.

DESIGN

Prospective, randomized, controlled, experimental study.

SETTING

Animal research laboratory.

SUBJECTS

40 male Wistar rats.

INTERVENTIONS

The rats randomly received one of four treatments: infusion of saline (SAL) or Escherichia coli lipopolysaccharides (LPS) followed by treatment with saline (SAL) or NAC (150 mg.kg-1 body weight) 30 min after induction of endotoxemia.

MEASUREMENTS AND MAIN RESULTS

Leukocyte adherence, red blood cell velocity, and vessel diameters in postcapillary venules of rat mesentery were evaluated every 30 min over a period of 120 min using in vivo videomicroscopy. Vascular permeability was determined by measuring the extravasation of fluorescence-labeled albumin. Venular wall shear rate was calculated from red cell velocity, and vessel diameter. NAC in rats without endotoxemia (SAL + NAC group) compared to the control group (SAL + SAL) did not change microcirculatory parameters in postcapillary venules of rat mesentery. In both LPS-treated groups (LPS + SAL and LPS + NAC), leukocyte adherence increased after just 30 min. NAC treatment prevented a further increase in leukocyte adherence and attenuated the extravasation of fluorescence-labeled albumin during endotoxemia. Venular diameters remained unchanged, while erythrocyte velocity decreased in the LPS + SAL group. This led to a lower venular wall shear rate in this group.

CONCLUSIONS

Treatment with NAC attenuates endotoxin-induced leukocyte adherence and macromolecular leakage in postcapillary venules of rat mesentery, showing that NAC is also effective after the onset of endotoxemia.

Cholinesterases in cardiac ganglia and modulation of canine intrinsic cardiac neuronal activity

Cholinergic neurotransmission plays a significant role in intrinsic cardiac ganglia with the action of acetylcholine being terminated by acetylcholinesterase (AChE, EC 3.1.1.7). Anatomical studies were performed to characterize neurons associated with AChE and a closely related enzyme, butyrylcholinesterase (BuChE, EC 3.1.1.8), in canine intrinsic cardiac ganglia. Histochemical staining for AChE and BuChE in canine right atrial neurons showed that there were four neuronal populations, namely, those that contained AChE only, BuChE only, both AChE and BuChE, and those that did not contain either enzymes. The neuronal activity of intrinsic cardiac neurons in response to substrates and inhibitors of cholinesterases were studied in anesthetized dogs. The activity of intrinsic cardiac neurons, as measured by changes in the number of action potentials, increased by local application of acetylcholine. However, local application of butyrylcholine led to a considerably greater increase in the activity of intrinsic cardiac neurons. In keeping with the neurochemical heterogeneity in intrinsic cardiac ganglia with respect to cholinesterases, the activity generated by most butyrylcholine-sensitive neurons was not influenced by acetylcholine and the activity generated by the most acetylcholine-sensitive neurons was not influenced by butyrylcholine. This suggests that these two agents preferentially influence different populations of intrinsic cardiac neurons. Enzyme kinetic studies demonstrated that canine AChE preferentially catalyzed the hydrolysis of acetylcholine while canine BuChE preferentially catalyzed the hydrolysis of butyrylcholine. Cholinesterase inhibitors Ro 2-1250 and Ro 2-0638 inhibited both canine cholinesterases, while huperzine A preferentially inhibited canine AChE and ethopropazine inhibited canine BuChE. The activity of neurons in the intrinsic cardiac ganglia significantly increased when Ro 2-1250 or Ro 2-0638 was administered locally. The activity of neurons was not affected when huperzine A or ethopropazine was administered, indicating that both cholinesterases must be inhibited to increase neuronal activity. In summary, these data show that in addition to AChE, intrinsic cardiac ganglia also contain distinct populations of neurons that are associated with BuChE, and the activity generated by these neurons is differentially influenced by their substrates. Because simultaneous inhibition of AChE and BuChE leads to increased neuronal activity, it is concluded that AChE- and BuChE-positive intrinsic cardiac neurons may act synergistically to influence the overall tonic activity of intrinsic cardiac ganglia.

[Guidelines for the evaluation of internal quality control of smears for screening of uterine cancer in France in the structures of Pathologic Anatomy and Cytology. French Association for Quality Assurance in Pathologic Anatomy and Cytology (AFAQAP)--Commission for cervical smears]

A national organized mass-screening effective programme is the only way to reduce the risk of cervical cancer, if properly organized and correlated with a system of Quality Assurance. Since 1900, an Association for Quality Assurance was created by the French pathologists, named "AFAQAP". These pathologists thus demonstrated their interest in this kind of action that should be effective if women and clinicians are also implied. The pathologists have concluded the first part of their programme with these French guidelines for internal quality control of pap smears.

Group B streptococcal bacteraemia in the elderly

The aim of this retrospective study was to determine the clinical spectrum of group B streptococcal (GBS) bacteraemia in patients over 70 years old. Sixty-six adults with GBS bacteraemia were reviewed over a 5-year period. Disease characteristics, clinical diagnoses and underlying disease were compared in 33 older patients (mean age 82.4 years) and 33 younger patients (mean age 54.2 years). The older patients were also compared with a control group (mean age 81.3 years). Urinary tract infection (39%), skin infection (33%) and pneumonia (24%) were the most frequent clinical diagnoses in older patients. Urinary tract infection (39% versus 6%) was significantly more frequent in older than in younger patients. One underlying disease and one condition were more frequent in elderly patients: congestive heart failure (39% versus 6%) and being bedridden (36% versus 0%). A comparison with the older control group showed that being bedridden was highly associated with GBS bacteraemia and was an important mortality factor amongst older patients (10% versus 30%). In conclusion, GBS disease in the elderly was found to be a severe clinical problem with a high mortality despite appropriate treatment.