Computed tomography perfusion imaging in acute stroke

The development of thrombolytic and neuroprotective agents for the treatment of acute stroke has created an imperative for improved imaging techniques in the assessment of acute stroke. Five cases are presented to illustrate the value of perfusion CT in the evaluation of suspected acute stroke. To obtain the perfusion data, a rapid series of images was acquired without table movement following a bolus of contrast medium. Cerebral blood flow, cerebral blood volume and mean transit time were determined by mathematically modelling the temporal changes in contrast enhancement in the brain and vascular system. Pixel-by-pixel analysis allowed generation of perfusion maps. In two cases, CT-perfusion imaging usefully excluded acute stroke, including one patient in whom a low-density area on conventional CT was subsequently proven to be tumour. Cerebral ischaemia was confirmed in three cases, one with an old and a new infarction, one with a large conventional CT abnormality but only a small perfusion defect, and one demonstrating infarct and penumbra. Perfusion CT offers the ability to positively identify patients with non-haemorrhagic stroke in the presence of a normal conventional CT, to select those cases where thrombolysis is appropriate, and to provide an indication for prognosis.

Plasma haptoglobin concentration in swine after challenge with Streptococcus suis

Eight 15-week-old pigs, reared under specific pathogen-free conditions, were inoculated with Streptococcus suis serotype 2. The animals were monitored before and after challenge by measuring rectal temperature, recording specific clinical symptoms and collecting blood samples for haptoglobin determination. Twenty-four hours after infection, the average haptoglobin plasma concentration of the animal group increased significantly and reached a maximum 4 days post-inoculation, followed by a constant mean level until the end of the trial on day 10. In spite of individual differences between the animals, an increase in haptoglobin concentration of at least 2.5 times above normal was observed in all infected pigs 1 day after challenge. Twenty-four hours after challenge, lameness was observed in five animals and an elevated body temperature was observed in seven of the eight experimental infected animals. These are the classical clinical symptoms of streptococcal infection. Haptoglobin was shown to increase in acute S. suis infection in pigs.

Anoxic activated sludge monitoring with combined nitrate and titrimetric measurements

An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow for frequent measurements, and thereby the possibility for detailed determination of the denitrification biokinetics. An internal nitrate electrode calibration is implemented in the experiments to avoid the often-encountered electrode drift problem. It was observed that the best experimental design was with the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor and carbon source during denitrification.

The processing and utilization of hepatocyte growth factor/scatter factor following partial hepatectomy in the rat

Hepatocyte growth factor/scatter factor (HGF/SF) is a pluripotent growth factor capable of acting as a motogen, a morphogen, and a mitogen. Originally, HGF/SF was found as a blood-borne mitogen for hepatocytes and has since been determined to be very important in liver repair. Previous studies have established that HGF/SF must be proteolytically cleaved to elicit its effects. After liver injury by toxins such as carbon tetrachloride or after surgical resection, partial hepatectomy (PHX), HGF/SF concentrations increase in the blood. The aims of this study were to examine (1) which form of HGF/SF is present in the normal liver, (2) which form is present in the regenerating liver after PHX, and (3) if the HGF/SF used after PHX is derived from existing liver reservoirs. Both single-chain HGF/SF and active two-chain HGF/SF are present in normal liver, with the former being the dominant form. After PHX, the liver can be described as having two phases with regard to the use of endogenous HGF/SF. The first phase from 0 to 3 hours is the consumptive phase and is characterized by a decrease in both single-chain HGF/SF and active two-chain HGF/SF. The second phase is the productive phase. It is characterized by a pronounced reappearance of both single-chain HGF/SF as well as two-chain HGF/SF. The activation index shows a 5-fold increase over sham operations during the productive phase. The use of radiolabeled HGF/SF showed that during the first 3 hours, HGF/SF is used in part from hepatic stores. Furthermore, during the first 3 hours after PHX, only active two-chain HGF/SF is seen in the plasma.

The concept of hereditary impairment of brain maturation

The classification of benign partial epilepsies and related conditions includes (besides rolandic epilepsy) atypical benign partial epilepsy, bioelectrical status epilepticus (ESES) and a variety of other syndromes. The broad overlap of the clinical and bioelectrical symptomatology might reflect a pathogenetic background common to these epilepsies. In order to understand the great phenotypic variability, the clinical symptomatology in 56 sibships with focal sharp waves of genetic origin was analyzed. A genetic determination was assumed if, in addition to the index case, at least one sibling or offspring revealed typical focal sharp waves. The 56 index-cases and their 61 sib/offspring/parents showed a broad spectrum of epileptic and non-epileptic conditions ranging from mild selective performance deficits to severe complex mental retardation, from neonatal seizures, febrile convulsions, and simple rolandic epilepsy to severe epilepsies with minor seizures or ESES. The different conditions are not disease entities but sets of variably weighted symptoms of a complex pathogenetic background, in which a genetic disposition to focal anomalies of brain function is of decisive importance. As can be demonstrated by the data, this genetic liability coincides with other widespread genetic traits, expressed in certain EEG patterns, as well as with lesional pathogenetic factors. The biological background of the genetic focal anomaly is currently unknown. The marked age dependence of the symptoms justifies the assumption of an hereditary impairment of brain maturation.

An unusual FGFR1 mutation (fibroblast growth factor receptor 1 mutation) in a girl with non-syndromic trigonocephaly

Non-syndromic trigonocephaly is a heterogeneous entity; in most cases the origin is unknown. Rare cases with autosomal dominant and recessive inheritance exist. Here the mutational screening of ten patients in the FGFR1, 2, and 3 genes and the TWIST gene causative of autosomal dominant craniosynostosis syndromes was reported. In one girl an unusual FGFR1 mutation was found.

Activated sludge monitoring with combined respirometric-titrimetric measurements

A short review of different respirometric methods is presented, and advantages and disadvantages of different principles are discussed. In this study a combined respirometric-titrimetric set-up was applied to monitor the degradation processes during batch experiments with activated sludge. The respirometer consists of an open aerated vessel and a closed non-aerated respiration chamber. It is operated with two oxygen probes resulting in two sources of information on the oxygen uptake rate; both collected at a high frequency. The respirometer is combined with a titrimetric unit that keeps the pH of the activated sludge sample at a constant value through the addition of acid and/or base. The cumulative amount of added acid and base serves as a complementary information source on the degradation processes. Interpretation of respirometric data resulting from validation experiments (additions of acetate and urea as ammonium source) showed that the set-up provided reliable data. Data interpretation was approached in two ways: (1) via a basic calculation procedure, in which the oxygen uptake rates were obtained by an oxygen mass balance over the respiration chamber, and (2) via a model-based procedure in which substrate transport was included for a more accurate data interpretation. Simulation examples showed that the presence of substrate transport in the model may be crucial for a correct data interpretation, since experimental conditions (e.g. low flow rate) and/or the biodegradation kinetic parameters (e.g. high Ks) may otherwise lead to data interpretation errors. Earlier studies already pointed out that titrimetric data can be related to nitrification, and this was also confirmed in this study. However, in addition, it was shown here for experiments with acetate that the amount of acid dosed was clearly related to the amount of acetate degraded. This indicates that the titrimetric data can be used to study the carbon source degradation. For the titrimetric data in this study, a model-based analysis was however only applied for the nitrification process. For an experiment with ammonium, it was illustrated that the estimation of biodegradation kinetics on a combined respirometric-titrimetric data set significantly improves confidence intervals of the parameters compared to the parameter estimation based on respirometric or titrimetric data separately.

Intravascular US-guided direct intrahepatic portacaval shunt with a PTFE-covered stent-graft: feasibility study in swine and initial clinical results

PURPOSE

To determine the feasibility of the creation of a direct intrahepatic inferior vena cava (IVC)-to-portal-vein shunt with puncture guided by a transfemorally placed intravascular ultrasound (IVUS) probe and use of a polytetrafluoroethylene (PTFE)-covered stent-graft.

MATERIALS AND METHODS

In five swine, transjugular access was used to perform a direct puncture from the IVC to the portal vein with use of a modified Rosch-Uchida Portal Access set directed with real-time IVUS (9 MHz) introduced from a transfemoral venous approach. The direct intrahepatic portocaval shunt (DIPS) was then created with single or overlapping PTFE-covered Palmaz stents placed through a 10-F sheath and dilated to a diameter of 8 mm. Follow-up was performed with transhepatic portography at 2, 4, and 8 weeks. Animals were killed when shunts occluded or at the termination of the study at 8 weeks. Gross and microscopic histologic study was performed on sacrificed animals. A similar technique was used to create DIPS in five patients with intractable ascites, with follow-up by US and venography.

RESULTS

All experimental DIPS created in swine were created without complications. Portal vein punctures were achieved in four of five swine on the first or second pass of the needle. Follow-up transhepatic portography at 2 weeks demonstrated occlusion of two shunts, both explained by technical reasons at sacrifice. At 4 and 8 weeks, the remaining three shunts were patent on portography. Histology showed a thin neointimal lining with no significant tissue ingrowth or hyperplasia. Clinically, in five patients, successful puncture of the portal vein from the IVC was achieved in one to three passes. Creation of DIPS led to a reduction of mean portosystemic gradient from 18-29 mm Hg (mean, 24 mm Hg) to 9-10 mm Hg (mean, 9 mm Hg). One patient died of liver failure 2 days after creation of DIPS. The other four patients were doing well 2-15 months (mean, 8 months) after the procedure, with patency confirmed by US and venography.

CONCLUSION

Creation of DIPS is technically feasible, and the direct IVC-to-portal-vein puncture can be done accurately with real-time IVUS guidance. Further studies and longer follow-up are necessary to determine if the short length of the PTFE-covered stent-graft and avoidance of the hepatic vein will increase the long-term patency compared to standard transjugular intrahepatic portosystemic shunt creation.

Bifurcated drum occluder endograft for treatment of abdominal aortic aneurysm: an experimental study in dogs

PURPOSE

To evaluate a new, low profile, home-made, bifurcated drum occluder endograft (BDOEG), designed for percutaneous, transcatheter treatment of abdominal aortic aneurysm (AAA).

MATERIALS AND METHODS

AAA was created in 10 dogs with over-dilated Palmaz stents. To prevent back filling, the lumbar arteries, inferior mesenteric artery, and common internal iliac arteries were embolized. The BDOEG was constructed of a drum occluder device and two PTFE endografts. The drum device consisted of a modified Z stent with Dacron stretched across and held within the ends of the stent, each with two 8 x 6-mm slits through which PTFE endografts were delivered. The PTFE endografts were 8 mm in diameter and 9.5 cm in length. Preloaded, the BDOEG was delivered through a 10-F sheath from both femoral arteries in a three-step procedure. All 10 animals were treated with BDOEG. Aortography was performed immediately, 6 weeks, and 12 weeks after stent-graft placement. Five animals were killed at 6 weeks and five were killed at 3 months. Gross and histologic evaluation was performed.

RESULTS

The infrarenal aortic diameters and both external iliac arteries ranged from 8.0 mm to 10.3 mm (mean, 9.4 mm +/- 0.6) and from 5.2 mm to 6.8 mm (mean, 5.8 mm +/- 0.5), respectively. Creation of the AAA was successful in all 10 dogs. AAA diameters ranged from 13.7 mm to 15.9 mm (mean, 14.9 mm +/- 0.7). Complete exclusion of the AAA was achieved immediately after BDOEG placement and aneurysms remained excluded without perigraft leak to the time of killing in all 10 animals. There was a high incidence of aortoiliac limb occlusion. Occlusion of 12 aortoiliac limbs (60%) caused by intimal hyperplasia at the distal end of the endografts in iliac arteries developed in nine animals (90%). In six animals (60%), one limb occluded and, in three animals (30%), there was occlusion of both limbs.

CONCLUSION

This study suggests a new approach for treatment of AAA. BDOEG use reduces sheath size for endograft delivery and may eliminate the need for a surgical cut down on femoral arteries. Tapering of the iliac ends of endografts to the size of the artery will be needed to prevent distal intimal hyperplasia.

Excimer laser-assisted extraction of an infected bipolar left ventricular pacing lead implanted 10 years ago

Routine intraoperative transesophageal echocardiography (TEE) revealed a previously undiscovered ventricular positioning of an infected ventricular lead left in place for 10 years. This case report describes successful removal of this lead from the left ventricle by means of excimer laser and discusses some important aspects to be considered.

Practical identifiability of model parameters by combined respirometric-titrimetric measurements

An earlier study on theoretical identifiability of parameters for a two-step nitrification model showed that a unique estimation of the yield YA1 is possible with combined respirometric-titrimetric data, contrary to the case where only one type of measurement is available. Here, the practical identifiability of model parameters was investigated via evaluation of the output sensitivity functions and the corresponding Fisher Information Matrix (FIM). It appeared that the FIM was not sufficiently powerful to predict the practical identifiability of this case with combined measurements as parameters could indeed be identified despite the fact that the FIM became singular. The accuracy of parameter estimates based on respirometric and titrimetric data and combination thereof was also investigated. Estimation on titrimetric data (Hp) was very accurate and a fast convergence of the objective function towards a minimum was obtained. The latter also holds for estimation on oxygen uptake rate data (rO), however with a lower accuracy. Parameter estimation based on oxygen concentration data (SO) was more complex but resulted in a higher accuracy. Thus, when the highest accuracy is needed it is recommended to estimate parameters initially on Hp and/or rO data, and to subsequently use these parameters as initial values for final, and more accurate estimation on SO data.

Monitoring of denitrification performance with combined nitrate and titrimetric measurements

A sensor based on on-line measurement of nitrate and acid/base titration is proposed for anoxic activated sludge monitoring. The data probed from the preliminary experiments with denitrifying activated sludge samples using anoxic-titrimetric sensor are information-rich with high data frequency that can be used further in model-based data interpretation and parameter estimation of denitrification process. Moreover, the sensor was able to detect intermediate accumulation, which is an often-observed phenomenon during the denitrification process. It therefore offers the possibility for use in overall performance evaluation of biological nutrient removal plants.

Unusual pattern of leukoencephalopathy after morphine sulphate intoxication

We report a 14-year-old girl with an unusual pattern of leukoencephalopathy after intentional intoxication with morphine sulphate tablets. Toxicological analysis showed exceedingly high levels of morphine and its metabolites. MRI disclosed a leukoencephalopathy with high signal from the centrum semiovale, corpus callosum and cerebellar white matter on T2-weighted images. These findings could be only partially explained by a hypoxic-ischaemic event; neurotoxic effects must be considered in this atypical leukoencephalopathy.

The incidence of positive margins with breast conserving therapy following mammotome biopsy for microcalcification

BACKGROUND AND OBJECTIVES

The ability to achieve clean margins with breast conserving therapy varies greatly even when the diagnosis of carcinoma is known beforehand. Although several reports reveal that the incidence of positive margins decreases after stereotaxic core biopsy of nonpalpable lesions and fine-needle aspiration biopsy of palpable lesions, the data on the results following mammotome biopsy (mmbx) is scanty.

METHODS

Two hundred and ninety-eight biopsy specimens for mammographically indeterminate microcalcification from 1/97 through 3/30/98 were reviewed. Biopsies were performed using the biopsys method utilizing an 11-gauge multidirectional, vacuum-directed device.

RESULTS

Ten percent (n = 31) of the mammotome biopsies were atypical and 9% (n = 27) were malignant. These 58 cases (19%) were recommended for surgical excision. The incidence of positive margins in this subset was determined. Of patients who underwent lumpectomy as their initial surgical procedure 69% had negative surgical margins. Seventy-seven percent of patients with carcinoma diagnosed by mammotome biopsy had definitive initial surgery with a single surgical procedure.

CONCLUSIONS

Mmbx facilitates fewer surgical procedures to achieve negative margins, and thus provides a better cosmetic result.

Combination therapy with carvedilol and amiodarone in patients with severe heart failure

BACKGROUND

Carvedilol and at least in some studies, amiodarone have been shown to improve symptoms and prognosis of patients with heart failure. There are no reports on the outcome of combined treatment with both drugs on top of angiotensin-converting enzyme inhibitors (ACEI), diuretics and digitalis.

METHODS AND RESULTS

In 109 patients with severe heart failure submitted for heart transplantation at one single center between the years 1996 and 1998 [left ventricular ejection fraction (LVEF) 24.6+/-11%, 85% males, 52% idiopathic dilated cardiomyopathy (DCM), mean observation time 1. 9+/-0.4 years] a therapy with low-dose amiodarone (1000 mg/week) plus titrated doses of carvedilol (target 50 mg/day) was instituted. In addition, patients received a prophylactic dual chamber pacemaker (PM) in order to protect from bradycardia and for continuous holter monitoring. The devices were programmed in back-up mode with a basal rate of 40 i.p.m. with a hysteresis of 25%. Significantly, more patients were in sinus rhythm after 1 year than at study entry (85% vs. 63%, P<0.01). In 47 patients, under therapy over at least 1 year, the resting heart rate fell from 90+/-19 to 59+/-5 b.p.m. (P<0.001). Ventricular premature contractions in 24-h holter ECGs were suppressed from 1.0+/-3 to 0.1+/-0.3%/24 h (P167 b.p.m. detected by the pacemaker (1.2+/-2.8 episodes/patient/3 months vs. 0.3+/-0.8 episodes/patient/3 months after 1 year (P<0.01). The LVEF increased from 26+/-10 to 39+/-13% (P<0.001). NYHA class improved from 3. 17+/-0.3 to 1.8+/-0.6 (P<0.001) as well as right heart catheterization data. From the total cohort, seven patients (6%) developed symptomatic documented bradycardic rhythm disturbances requiring reprogramming of their pacemakers to DDD(R)/VVI(R) mode with higher basic rates. Two of these patients developed AV block, four sinu-atrial blocks or sinus bradycardia and one patient had bradycardic atrial fibrillation. During the observation period five patients died (3 sudden, 1 due to heart failure and 1 due to mesenteric infarction). Two patients had undergone heart transplants. The 1-year survival rate (Kaplan-Meier) without transplantation was 89%. Compared to historic control patients with amiodarone only (n=154) or without either agent (n=283) this rate was 64 and 57% (P<0.01).

CONCLUSIONS

Heart failure patients benefit from a combined therapy with carvedilol and amiodarone resulting in a markedly improved NYHA stage, an increase in LV ejection fraction, a stabilization of sinus rhythm, a significant reduction in heart rate, a delay of electrical signal conduction and a suppression of ventricular ectopies. Approximately 6% of patients under such a regime became pacemaker-dependent in the first year. Compared to historic controls prognosis was better and the need for heart transplantation was lower. The exact role of either agent in combination or alone should be clarified in larger randomized studies.

Efficacy of a computerized local anesthesia device in pediatric dentistry

PURPOSE

The purpose of this study was to evaluate the efficacy of a computerized anesthesia delivery system in reducing pain during injections when compared with a traditional delivery system (i.e., syringe).

METHODS

Subjects consisted of 57 patients between the ages of 5 and 13 needing operative dentistry using local anesthesia. Patients were randomly assigned to either the computerized or traditional anesthesia delivery system. Inferior alveolar block injections, palatal, and buccal infiltrations were the only injections administered throughout this study. Pain behavior was videotaped and coded throughout the study. Pain perceptions were rated using a 10 point visual analogue rating scale. Subjects were also asked to rate their overall satisfaction and approval of the dentist and the treatment received.

RESULTS

Results of multivariate analysis of variance indicated that there were no significant differences between the computerized and the traditional method of administering local anesthesia when comparing pain ratings and pain behavior. Average pain ratings for the computerized method were 4.5 while the average ratings for the traditional method were 3.6. In addition, all subjects reported overall satisfaction with their dental treatment and that they would be willing to return in the future.

CONCLUSIONS

A computerized anesthesia injection method was found to be comparable to the traditional method of anesthesia injection.

Early discharge with home health care in the coronary artery bypass patient

Early hospital discharge after coronary artery bypass graft surgery has been the standard of practice throughout the United States. This study compared outcomes, readmissions, and costs for patients discharged early with home health care with those of patients discharged a day or more later without home health care. Discharging open-heart surgery patients on postoperative day 4 with home health care was found to be safe and cost-effective.

Effect of orlistat on blood cyclosporin concentration in an obese heart transplant patient

OBJECTIVE

We detected markedly decreased cyclosporin blood levels in a heart-transplanted patient after the gastrointestinal lipase inhibitor orlistat was accidentally added to the treatment program to control for his obesity. Therefore, we determined cyclosporin plasma concentration time kinetics with and without orlistat reexposition in this patient.

METHODS

Plasma concentration time kinetics of whole blood cyclosporin levels in an obese heart-transplant patient were measured using a standard monoclonal fluorescence polarisation immunoassay. Results were obtained in hourly intervals up to 12 h without and with co-therapy of 3 x 120 mg orlistat (Xenical, Roche Ltd., Switzerland). The orlistat re-exposition was started the day before taking blood samples.

RESULTS

Cyclosporin trough levels (98 ng/ml vs 52 ng/ml), maximum concentrations (532 ng/ml vs 74 ng/ml) and the area under the blood drug concentration-time curve (2832 ng h ml-1 vs 700 ng h ml-1) were greatly reduced with orlistat.

CONCLUSIONS

Orlistat markedly decreased blood cyclosporin concentrations, possibly due to an interference with its absorption in the small intestine. To avoid potential dangerous under-immunosuppression, orlistat should not be used in patients taking cyclosporin.

Haemolytic complement activity and C3c serum concentration in pigs

Abstract. Because of the importance of the complement system in disease resistance through direct lysis of target cells and support of other mechanisms of the immune System, individual Variation in haemolytic complement activity and C3 concentration in pigs prior and after vaccination were evaluated. Possible effects on the variation of these parameters were investigated. Total complement activity was determined based on complement-mediated haemolysis of antibody-sensitised erythrocytes and C3c levels were measured by immunonephelometry in Gemian Landrace pigs and an experimental pig population. Both methods revealed remarkable individual differences. The arithmetic means of total haemolytic complement activity including all pigs were 42.3 ± 28.2 U/ml before vaccination and 59.1 ± 50.6 U/ml after three immunisations. Mean plasma concentrations of C3c were between .102 ± .035 g/1 before immunisation and .126 ± .038 g/1 on day 4 after Aujeszky vaccination. Existing phenotypic variation may be in part influenced by pig genetic factors. Both haemolytic complement activity as well as C3c semm levels are potentially useful measures of complement capacity on the way to improve defence power against many pathogens by breeding.

Critical illness neuropathy in pediatric intensive care patients

Critical illness neuropathy is an axonal polyneuropathy recognized more frequently in adult intensive care patients with sepsis and multiple organ dysfunction. In children the diagnosis is rarely made. Within 1 year the authors observed two children with critical illness neuropathy. Both patients, a male 6 years, 6 months of age with a brain contusion and a male 2 years, 6 months of age who underwent craniectomy for Crouzon's disease, required prolonged mechanical ventilation and developed sepsis with multiple organ dysfunction. Three to 4 weeks after successful treatment of the sepsis, a flaccid tetraparesis was noticed in both patients. Laboratory investigations of blood and cerebrospinal fluid and spinal magnetic resonance imaging revealed normal results. Electrophysiologic examinations were indicative of an axonal polyneuropathy. Spontaneous improvement occurred within several months. It is likely that critical illness neuropathy occurs more often in critically ill children than previously thought. Careful neurologic examination and early electrophysiologic investigations are necessary to establish the diagnosis. Important differential diagnoses of acquired lower motor neuron weakness in pediatric intensive care medicine are discussed.