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Biomedical subjects

A Haass

Publications and source records attributed to A Haass.

At least 19 recordsLinked to original sources
PubMed1998

[Value of antibody titers for diagnosis of neuroborreliosis].

Neuroborreliosis is a very frequent subtype of infection with Borrelia burgdorferi. Because of the widely spread inapparent infections finding of diagnosis by analysis of serum antibodies is very difficult. In the years 1990-1994 the serum of 6.775 patients of the Department of Neurology in Homburg, Germany was analysed with regard to Borrelia burgdorferi specific IgG antibodies. 24% showed a positive serum titer and 20% a borderline result. 73 patients showed a specific intrathecal IgG antibody synthesis. In contrast to patients with antibodies in serum these patients showed a significant cumulation during summer. The high percentage of positive serum titers and the season independence support the assumption of widely spread inapparent infections. If a patient shows neurological symptoms the finding of serum antibodies against Borrelia burgdorferi is not sufficient for the diagnosis of Neuroborreliosis. A specific intrathecal synthesis of antibodies, is the most reliable serological indicator for Neuroborreliosis. Intrathecal synthesis usually starts three to four weeks after the first clinical symptoms.

Antibodies, Bacterial↗
PubMed1998

Prevalence of antibodies to tick-borne encephalitis virus and Borrelia burgdorferi sensu lato in samples from patients with abnormalities in the cerebrospinal fluid.

Within the last few years, an increase in cases of tick-borne encephalitis (TBE) as well as an expansion of TBE-endemic regions have been noted in southern Germany. In 1994, a patient was diagnosed for the first time with TBE that had been acquired in Saarland. Up to this point, the Saarland had been considered TBE-free. In a retrospective study, we tested serum samples from 904 patients with abnormalities in the cerebrospinal fluid (CSF) for TBE antibodies. The IgG ELISA used (Immunozym-FSME-IgG, Immuno GmbH, Heidelberg, Germany) yielded 47 positive and 134 borderline sera. The percentage of positive sera showed a significant increase during the time period studied (1989-1994): One IgG-positive serum sample was also IgM-positive. Of the CSF samples, 2 were IgG-positive and 7 were borderline for IgG. In three patients, a positive intrathecal antibody index (IAI) was found, indicating an incrathecal antibody production. An analysis of the vaccination history of the patients showed that only 19% of the patients with a positive TBE IgG titre and only 5.9% of the borderline patients had been vaccinated against TBE. We compared 98 patients that tested positive or borderline for TBE IgG with 98 sex-and-age-matched patients that tested negative. The parameters studied included the patient's complaints upon discharge, the average duration of stationary treatment and 16 different neurological symptoms. We did not observe any significant differences between the two groups. We also tested the sera of 704 of the 904 patients for antibodies to Borrelia burgdorferi (Borrelia burgdorferi ELISA, Genzyme Virotech GmbH, Rüsselsheim, Germany). 155 (22.0%) of the sera were IgG-positive, 136 (19.3%) were borderline, 32 patients (4.6%) had a positive intrathecal antibody index (IAI). The fact that no patient with a clinically manifest case of TBE had acquired the disease in the Saarland indicates that the actual risk of acquiring an acute TBE in the Saarland is very low, despite the high percentage of samples that tested positive for IgG in the ELISA. The increase in the number of serum samples that tested positive for TBE IgG during the last years could be explained by an expansion of TBE regions into the Saarland, increasing vaccination of the population or more travel to endemic regions. The proportion of patients with IgG antibodies to Borrelia was 22%. Because only part of the patients suffered from an acute, clinically manifest borreliosis, and since the serum IgG titre had remained positive for many years after contact with the microorganisms, we suspected that a large percentage of the population would show signs of a clinically silent infection in their sera. 4.6% of the patients had a positive IAI quotient, a clear indication of neuroborreliosis.

Antibodies, Bacterial↗
PubMed1998

Lyme neuroborreliosis.

A broad variability in the clinical manifestations is observed in the European and North American borrelioses. This is dependent on bacterial strain differences in virulence and organotropism, and on different immune responses to Borrelia burgdorferi of the host in these areas. Experimental neuroborreliosis has given insights into mediators and molecular mechanisms of inflammation induced by B. burgdorferi. Histopathological investigations have described the different patterns of injury in the peripheral and central nervous systems. The classic symptoms of neuroborreliosis have been supplemented by new clinical syndromes and neuropsychological investigations. In clinical trials, the efficacy and cost effectiveness of recommended oral and intravenous antibiotic therapies have been compared in early Lyme disease, arthritis and acute disseminated Lyme disease.

Humans↗
PubMed1998

Transcranial doppler monitoring of intracranial pressure therapy with mannitol, sorbitol and glycerol in patients with acute stroke.

INTRODUCTION: The noninvasive management of the conservative therapy for intracranial pressure (ICP) with hyperosmolar substances is a central problem in the treatment of brain edema. Using transcranial Doppler (TCD), a continuous monitoring of ICP is now possible, because the TCD pulsatility index (PI) intraindividually closely correlates with the level of ICP. PATIENTS AND METHODS: We administered an ICP-lowering treatment 113 times in 10 patients with intracranial bleeding or ischemic stroke who also had signs of elevated ICP in the computer tomogram. The treatment was carried out over a period of 9 days, using 50 g each of intravenous sorbitol (n = 38) and mannitol (n = 32) or oral glycerol (n = 43). RESULTS: PI was significantly lowered between 20.0 and 23.9% (p < 0.01) by all substances in the affected and unaffected sides. The differences between the three substances and the differences between the affected and unaffected sides were not significant. The duration of the therapeutic effect of glycerol (190 +/- 41 min) was significantly longer (p < 0.01) than that of sorbitol (150 +/- 28 min) or mannitol (130 +/- 20 min). The duration of the therapeutic effect was also significantly shorter (p < 0.01) in patients with a high PI (> 1.5). All three substances led to a significant increase (p < 0.01) in minimal (= diastolic) flow velocity (Vmin). The increase was highest for glycerol (56.3 +/-72.6%). SUMMARY: The decrease in PI under therapy was caused by an increase in Vmin. This indicates that ICP therapy with hyperosmolar substances improves brain edema and does not suggest a therapy-induced vasoconstriction.

Acute Disease↗
PubMed1998

Thunderclap headache caused by Erve virus?

Systematic studies of a possible human neuropathogenicity of the Erve virus have not yet been carried out. In a randomized, blind study 166 patients with viral encephalitis, 46 patients with cerebral hemorrhage, 72 patients with "thunderclap" headache, and 205 healthy blood donors were examined by indirect immunofluorescence for Erve virus antibodies. None of the patients with encephalitis, two patients with cerebral hemorrhage (4.3%), 10 patients with thunderclap headache (13.9%; p < 0.0001), and two blood donors (1.0%) exhibited antibodies against the Erve virus. These results suggest a human pathogenicity of the Erve virus for the first time.

Adult↗
PubMed1998

Clinical and serologic follow-up in patients with neuroborreliosis.

The authors performed a clinical and serologic follow-up study after 4.2 +/- 1.2 years in 44 patients with clinical signs of neuroborreliosis and specific intrathecal antibody production. All patients had been treated with ceftriaxone 2 g/day for 10 days. Although neurologic deficits decreased significantly, more than half the patients had unspecific complaints resembling a chronic fatigue syndrome and showed persisting positive immunoglobulin M serum titers for Borrelia in the Western blot analysis.

Antibodies, Bacterial↗
PubMed1997

Increased haemorrhagic risk after repeated infusion of highly substituted medium molecular weight hydroxyethyl starch.

Infusion of the large volumes of high molecular weight hydroxyethyl starch (HES) has been know to lead to coagulation disorders. Medium molecular starch is considered a safe alternative, even after repeated administration. In 10 patients with cerebrovascular diseases, a 10-day hemodilution was carried out using 10% HES 200/0.62. Initially, a loading dose of 500 ml was administered once over 45-60 min, followed by 500 ml maintenance dose per day for 10 days. Its high intravascular molecular weight (120,000 D) showed that cleavage of the starch is slowed due to the higher degree of substitution. The continuous increase of HES-serum concentration to 27.7 mg/ml gave evidence of a cumulation of poorly degradable molecules. Although this caused a prolonged volume effect, plasma viscosity and erythrocyte aggregation were influenced in an unfavourable way. The negative effects were not evident in their influence on the coagulation system. Under therapy, a significant 42.8% increase (p < 0.01) in activated partial thromboplastin time occurred. Factor VIII:C, von Willebrand ristocetin co-factor and von Willebrand factor antigen dropped during the therapy below the hemostasiological limit of 30% (p < 0.01), and in some patients below 10%. A high degree of substitution, particularly after repeated infusion, leads to a cumulation of large molecules that are difficult to break down and which unfavourably affect rheological and hemostasiological parameters.

Blood Coagulation↗
PubMed1997

Coagulation disorders caused by hydroxyethyl starch.

Initially, hydroxyethyl starch (HES) was only characterized by its in vitro molecular weight (MW). This is not sufficient because HES is degraded in vivo. One relevant parameter that predicts the rate of enzymatic breakdown is the degree of substitution, a measure of the average number of hydroxyethyl groups per glucose unit. The higher this degree of substitution, the slower the break-down. In addition, because the glucose units can be substituted at carbon 2, 3 and 6, different substitution patterns are possible. They are classified by their C2/C6 hydroxyethylation ratio. A higher C2/C6 ratio results in less metabolism of the starch in vivo and results in a larger in vivo MW. This in turn affects therapy, because the larger the in vivo MW, the longer is the duration of the volume effect of HES. Of particular importance is the fact that HES with a high in vivo MW affects factor VIII/von Willebrand factor which can lead to an acquired von Willebrand syndrome. During a 10-day volume therapy with a medium-MW HES 200, a form that is difficult to metabolize, we observed an 80% drop in factor VIII/von Willebrand factor. Therapy with a medium-MW HES 200, a form that is easily degraded, and therapy with a low-MW HES 70 did not result in a relevant decline of factor VIII/von Willebrand factor. This explains why hemorrhagic complications have been observed repeatedly in the United States after therapy with HES infusions, some of them lethal. In the United States high-MW HES 480 which is difficult to degrade is most frequently used and results in a larger in vivo MW and subsequent decrease in factor VIII/von Willebrand factor levels. In Europe, medium-MW HES 200 that is easily degraded and low-MW HES 70 are preferred. In the future, HES should be characterized by the in vivo, not the in vitro MW.

Blood Coagulation Disorders↗
PubMed1996

Cardiac output in patients with acute stroke.

It is well known that blood pressure is elevated during acute stroke. Despite its importance for cerebral haemodynamics, cardiac output (CO) has been determined only in individual cases during acute stroke. We measured CO and blood pressure in patients with no history of heart disease who suffered from acute stroke (n = 30) and in a control group comparable with regard to age, gender and cardiac health (n = 30). CO, blood pressure and heart rate were significantly (P < 0.01) higher in the group of stroke patients than in the control group. There was a tendency for more time to have elapsed between the onset of symptoms and measurements, the higher the CO [b = 0.08 l/min per hour (-0.01; 0.17)]. Adjusted for age in a multiple regression model, the regression coefficient was significant (CO = 10.35 +0.094 x time -0.077 x age). The present study shows for the first time that patients with a healthy cardiovascular system who suffer from acute stroke have a higher CO than a group of comparable controls.

Acute Disease↗
PubMed1996

All medium starches are not the same: influence of the degree of hydroxyethyl substitution of hydroxyethyl starch on plasma volume, hemorrheologic conditions, and coagulation.

BACKGROUND: After the application of high volumes of high-molecular-weight starch (hetastarch), bleeding complications have repeatedly been observed. Later studies showed that the application of medium-molecular-weight starch led to far fewer disturbances of the blood coagulation system. However, the relationships among the degree of hydroxyethyl substitution, the rate of degradation, and the average in vivo molecular weight have not been investigated. STUDY DESIGN AND METHODS: A 10-day hemodilution treatment (n = 20) was carried out using two medium-molecular-weight hydroxyethyl starches (HES) with a degree of hydroxyethyl substitution of 0.5 and 0.62, respectively (10% HES 200 was used for a substitution of 0.5 and 6% HES 200 for a substitution of 0.62). After a loading dose of 500 mL was administered, 1000 mL of HES was infused daily for 4 days, and then 500 mL was infused daily for 6 days. RESULTS: The more highly substituted starch was broken down more slowly and eliminated renally. This resulted in a higher intravascular molecular weight than for the less highly substituted HES (120 vs. 84 kDa) and a greater increase in serum concentration (20.3 vs. 9.0 mg/mL). Initially, the more highly substituted 6-percent HES had a lesser effect on plasma volume (p < 0.01). Because of HES accumulation, there was no longer a significant difference between the starches by the end of treatment, even though a higher dose of the 10-percent low-substitution starch was infused. Six-percent HES caused an increase in plasma viscosity (+9%, p < 0.01) that was due to an accumulation of macromolecules. Ten-percent HES 200/0.5 had no effect on the coagulation system beyond the dilution effect. Six-percent HES, on the other hand, led to an acquired von Willebrand syndrome during the course of the 10-day therapy. Factor VIII function was reduced by 72.2 percent, von Willebrand ristocetin cofactor by 61.3 percent, and von Willebrand factor antigen by 64 percent (p < 0.01). CONCLUSION: It is the intravascular and not the initial (in vitro) molecular weight that determines the properties of HES. Especially after repeated administration, a high degree of hydroxyethyl substitution leads to an accumulation of macromolecules that affect hemorrheologic measures and the coagulation system just as adversely as high-molecular-weight starch does. Depending on the degree of substitution, medium-molecular-weight starches can have widely differing properties.

Blood Coagulation↗
PubMed1996

[Transcranial Doppler examination on effect of hemodynamics on cerebral autoregulation in acute cerebral infarct].

AIM: We treated 24 patients suffering from an acute ischemic stroke of the middle cerebral artery, with a hypervolemic hemodilution combined with dopamine/dobutamine. METHOD: The influence of blood pressure and cardiac output on the blood flow velocity in the middle cerebral artery was measured using transcranial Doppler sonography (TCD). RESULTS: Under the hypervolemic hemodilution supported with dopamine/dobutamine a dosage-dependent increase of 12% in blood pressure and a 53% increase in cardiac output was observed. In the affected hemisphere, flow velocity was one fourth lower (significance p < 0.05) than in the unaffected hemisphere. With therapy, the systolic flow velocity was increased in the unaffected hemisphere by 27%, on the side of the lesion only 11%. Mean flow velocity remained nearly constant. The pulsatility index (PI) increased simultaneously by 46% in the affected and 47% in the unaffected hemisphere. CONCLUSION: Similar effects on TCD-flow velocity and PI under comparable slight increases in blood pressure are not known. The increase in cerebrovascular resistance can be ascribed to a counter-regulation of the cerebral autoregulation, triggered by an increase of cardiac output.

Aged↗
PubMed1996

Influence of intravascular molecular weight of hydroxyethyl starch on platelets.

Complications concerning the blood coagulation have been observed repeatedly after administration of highly substituted, high molecular weight hydroxyethyl starch (HES), but it has not been examined as to how intravascular molecular weight and degree of substitution of HES influence platelet number and volume after repeated administration. Thirty patients with cerebrovascular diseases were treated for 10 days with hemodilution. 500 to 1500 ml of HES 200/0.62(n=10), HES 200/0.5(n=10) or HES 40/0.5(n=10) were infused daily. During the first days, the number of platelets was not lowered beyond the dilution effect, but at the end of the therapy the number of platelets had increased in all 3 groups beyond the initial value. Platelet volume was lowered significantly in the 3 groups. HES 200/0.62 caused the largest drop in platelet volume (-10%, p<0.01). A possible explanation could be that HES macromolecules are attached to platelets or are phagocytized by them. The larger platelets are then broken down and, to compensate the loss, more thrombocytes are released. A correlation between the molecular weight of HES and the breakdown rate of the platelets can be suspected, because HES 200/0.62 has the highest intravascular mean molecular weight(121 kD) and the largest effect on platelet volume.

Blood Platelets↗