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Biomedical subjects

L Willumsen

Publications and source records attributed to L Willumsen.

At least 19 recordsLinked to original sources
PubMed2000

Effects of graded hyperventilation on cerebral blood flow autoregulation in experimental subarachnoid hemorrhage.

An impaired CBF autoregulation can be restored by hyperventilation at a PaCO2 level of about 2.9 to 4.1 kPa (22 to 31 mm Hg). However, it is uncertain whether the restoring effect can take place at lesser degrees of hypocapnia. In the current study, CBF autoregulation was studied at four PaCO2 levels: 5.33 kPa (40 mm Hg, normoventilation), 4.67 kPa (35 mm Hg, slight hyperventilation), 4.00 kPa (30 mm Hg, moderate hyperventilation), and 3.33 kPa (25 mm Hg, profound hyperventilation). At each PaCO2 level, eight rats 2 days after experimental subarachnoid hemorrhage (SAH) and eight sham-operated controls were studied. The CBF was measured by the intracarotid 133Xe method. The CBF autoregulation was found to be intact in all controls but completely disturbed in the normoventilated SAH rats. However, by slight hyperventilation, CBF autoregulation was restored in seven of eight SAH rats with a decline in CBF of 10%. The CBF autoregulation was found intact in all of the moderately or profoundly hyperventilated SAH rats, whereas the decline in CBF was 21% and 28%, respectively. In conclusion, hyperventilation to a PaCO2 level between 4.00 and 4.67 kPa (30 to 35 mm Hg) appears to be sufficient for reestablishing an impaired autoregulation after SAH.

Animals↗
PubMed1998

The upper limit of cerebral blood flow autoregulation in acute intracranial hypertension.

The present series of experiments was performed to investigate the influence of acute intracranial hypertension on the upper limit (UL) of cerebral blood flow (CBF) autoregulation. Three groups of eight rats each--one with normal intracranial pressure (ICP) (2 mmHg), one with ICP = 30 mmHg, and one with ICP = 50 mmHg--were investigated. Intracranial hypertension was maintained by continuous infusion of lactated Ringer's solution into the cisterna magna, where the pressure was used as ICP. Cerebral perfusion pressure (CPP), calculated as mean arterial blood pressure (MABP)-ICP, was increased stepwise by continuous intravenous infusion of norepinephrine. CBF was calculated by the intracarotid 133Xe method. In all three groups the corresponding CBF/CPP curve included a plateau where CBF was independent of changes in CPP, showing intact autoregulation. At normal ICP the UL was found at a CPP of 141 +/-2 mmHg, at ICP = 30 mmHg the UL was 103+/-5 mmHg, and at ICP = 50 mmHg the UL was found at 88+/-7 mmHg. This shift of the UL was more pronounced than the shift of the lower limit (LL) of the CBF autoregulation found previously. We conclude that intracranial hypertension is followed by both a shift toward lower CPP values and a narrowing of the autoregulated interval between the LL and the UL.

Animals↗
PubMed1991

Bilateral sudden deafness and acute acquired toxoplasmosis.

An 18-year-old woman, while suffering from acute acquired toxoplasmosis, experienced sudden deafness and a total loss of vestibular function first in the right ear and three months later also in the left. Following treatment with sulphadiazine and pyrimethamine, hearing was retrieved to such a degree that the patient was enabled to communicate by means of a body-worn hearing aid and lip-reading. Taking the differential diagnostic possibilities into account, we believe that toxoplasmosis was the cause of the severe hearing loss. Since effective treatment seems to be available, we recommend that patients with acute bilateral sensorineural hearing loss of unknown origin are examined for acute toxoplasmosis with a view to instituting chemotherapy.

Acute Disease↗
PubMed1988

Blood-monocyte functions in acute bacterial meningitis.

The blood-monocyte chemotactic, phagocytic and microbicidal activities were studied in 20 patients with acute bacterial meningitis. The cell functions were measured on admission, during treatment and after clinical recovery. In general, monocyte functions were within normal range on admission. However, in 2/2 patients with Neisseria meningitidis meningitis, complicated by disseminated intravascular coagulation, defective chemotaxis was observed. Other patients had normal or enhanced monocyte chemotaxis. Two patients died: one had normal monocyte functions, one had initially defective chemotaxis and microbicidal activity. During treatment, cell functions normalized and after recovery all but one patient had a normal blood-monocyte function profile. In conclusion, acute bacterial meningitis is not due to, or followed by, abnormal nonspecific functions of blood monocytes. However, development of disseminated intravascular coagulation is associated with depressed chemotactic responsiveness.

Acute Disease↗
PubMed1987

Screening for complement deficiencies in unselected patients with meningitis.

Two hundred and nine patients consecutively admitted to hospital with a tentative diagnosis of meningitis were screened for complement deficiency by measuring classical and alternative pathway serum haemolytic complement activity and the plasma concentration of C3d. Abnormal test results were followed up by quantitative immunochemical measurements of individual complement components. No patients with homozygous complement deficiency were found in our material. One patient with pneumococcal meningitis with probable heterozygous C2-deficiency was identified. Patients with purulent meningitis of various etiologies or meningococcal disease had significantly increased plasma C3d concentration at admission compared to patients with serous meningitis or without meningitis. Furthermore, increased plasma level of C3d at admission in patients with purulent meningitis or meningococcal disease was associated with an increased lethality. Our findings do not support the hypothesis that complement deficiency is commonly associated with sporadically occurring meningococcal disease or purulent meningitis.

Adolescent↗
PubMed1986

Opsonic activity of serum in the acute phase of meningitis.

The present study was designed to determine the opsonic activity of serum obtained from meningitis patients in the acute stage of their illness. This study was part of a Danish multicentre prospective study on various aspects of meningitis for a 12-month period. The opsonic activity of serum was determined by a phagocytosis and a chemiluminescence assay using human peripheral blood polymorphonuclear leukocytes. The mean chemiluminescence and phagocytosis indices determined in the sera of 58 patients suffering from various forms of bacterial or non-bacterial meningitis did not differ significantly from that of control sera. Although sera of 4 patients with pneumococcal, 3 with meningococcal, and 1 with streptococcal meningitis exhibited lower opsonic activity than the control sera in the chemiluminescence assay, their values in the phagocytosis assay were similar to control value. It is concluded that serum opsonic activity in meningitis patients is normal and similar to that of healthy individuals.

Acute Disease↗
PubMed1984

Additional antacid does not increase the effect of cimetidine in gastric ulcer disease.

Eighty-one adult outpatients with endoscopically confirmed gastric ulceration were treated with cimetidine (1 g/day). In addition, the patients were allocated at random to either intensive antacid treatment or placebo treatment. This part of the study was double-blind. It was found that additional antacid treatment had no effect on ulcer healing and symptoms in cimetidine-treated gastric ulcer patients. The results were similar in patients with corpus ulcers and patients with prepyloric ulcers.

Adult↗
PubMed1983

Tropical anamnesis disguising malignant lymphoma.

The fatal history of 2 young men returning from the tropics is reported. The 1st case was characterized by recurrent fever and cholestatic jaundice, and the diagnostic and therapeutic efforts were directed towards exotic infection. Finally, indications of Hodgkin's disease were found and cytostatic treatment was tried unsuccessfully. Autopsy confirmed the diagnosis. The 2nd case was characterized by continuous fever and haemolysis requiring blood transfusion and prednisone. Tropical infection, among other things, was constantly suspected, but finally a liver biopsy demonstrated non-Hodgkin lymphoma. The diagnosis of malignant lymphoma in 2 previously healthy men was in both cases delayed by their stay in the tropics.

Adult↗