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Biomedical subjects

C Lindquist

Publications and source records attributed to C Lindquist.

At least 91 records · Page 5Linked to original sources
PubMed1987

Haem derivatives in the cerebrospinal fluid after intracranial haemorrhage.

During the first 5 days after an intracranial haemorrhage, the red blood cells slowly haemolyse. Most of the oxyhaemoglobin, released in the cerebrospinal fluid, is transformed into bilirubin by an enzyme-dependent process. After 5 days, the haemolysis increases without a corresponding enhancement in the formation of bilirubin. Consequently, the oxyhaemoglobin concentration also increases. A spontaneous oxidation of the haem group follows and after about 10 days the proportions of oxy- and methaemoglobin are about the same. This process occurs independently of the cause of the haemorrhage.

Bilirubin↗
PubMed1987

Natural history of postoperative aneurysm rests.

In a series of 715 patients operated on by microsurgical techniques for intracranial saccular aneurysms between 1970 and 1980, part of the aneurysmal sac was not obliterated in 28 aneurysms in 27 patients (3.8% of 715 cases). Clinical follow-up evaluation for 8 years (range 4 to 13 years) and angiographic follow-up studies for 6 years (range 2 to 10 years) in these 27 cases revealed that one aneurysm rest increased in size and bled twice, five were spontaneously obliterated, two decreased in size, 13 remained unchanged, and in seven cases no late follow-up angiography was performed. The incidence of rebleeding from an aneurysm rest was 3.7% of the 27 in whom the sac was not obliterated and 0.14% of all 715 patients who were operated on.

Adult↗
PubMed1987

A new fixation device for the Leksell stereotaxic system. Technical note.

A device is presented that permits several applications for the Leksell stereotaxic system. The patient is fixed in this new system by means of a rectangular instrument that connects to the standard Leksell stereotaxic coordinate frame and maintains spatial orientation after the frame itself is removed. Specific uses for this device include stereotaxic radiosurgery and stereotaxic guidance during microsurgery. Other attractive features of this device are its capability of being precisely reapplied, its compatibility with both computerized tomography and magnetic resonance imaging, and the availability of an accessory device to adapt it for animal stereotaxis.

Humans↗
PubMed1987

Clinical experience with adenosine for controlled hypotension during cerebral aneurysm surgery.

The cardiovascular effects of adenosine-induced hypotension were studied in 47 patients undergoing intracranial vascular surgery under neurolept anesthesia. Adenosine infusion (214 +/- 18 micrograms X kg-1 X min-1) decreased mean arterial pressure (MAP) by 42 +/- 1% from 80 +/- 1 to 46 +/- 1 mm Hg for an average of 29 +/- 5 min of hypotension. Hypotension was associated with a minor increase in heart rate (13 +/- 2%) and with prolongation of the PR interval (9 +/- 2%). ST-T depression did not occur except in one patient with a previous history of myocardial infarction. The adenosine-induced increase in cardiac index (42 +/- 9%, n = 7) was associated with a 63 +/- 10% decrease in systemic vascular resistance index (n = 7) while the pulmonary capillary wedge pressure remained unchanged. Adenosine metabolism was limited and there was no accumulation of the end metabolite, uric acid. Serum creatinine levels were normal in all patients postoperatively. We conclude that adenosine rapidly induces a stable and easily controlled hypotension in man without tachyphylaxis or rebound hypertension. There were no signs of renal or myocardial dysfunction except for dysrhythmias that occurred in two patients with a history of myocardial infarction.

Adenosine↗
PubMed1986

[Hemophilic arthropathy. A review and analysis of 30 patients].

Haemophilic arthropathy is one of the most important manifestations of haemophilia. Treatment of patients for haemophilia, in particular haemophilic arthropathies, has been considerably improved, after cryoprecipitates had been introduced in the late sixties. 30 haemophiliacs were examined by the authors of this paper, with all of them exhibiting lesions of knee-joints and ankle bones. Active surgical treatment, using modern methods, proved to be successful in 40 per cent of all cases of haemophilia.

Adult↗
PubMed1985

Increased concentrations of the monoamine metabolites homovanillic acid and 5-hydroxyindoleacetic acid in lumbar and central CSF and of 3-methoxy-4-hydroxyphenylglycol in lumbar CSF after subarachnoid haemorrhage.

The concentrations of the dopamine metabolite homovanillic acid (HVA), the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MOPEG) were determined in cerebrospinal fluid (CSF) from patients with subarachnoid haemorrhage (SAH) using a mass fragmentographic method. In a first group of 24 patients lumbar CSF was collected during the first 10 days after SAH. The concentrations of HVA and 5-HIAA showed a several-fold increase in the majority of subjects while that for MOPEG was less pronounced in comparison to controls. In a second group of 12 SAH-patients, CSF was collected in 10 ml fractions during surgical clipping of aneurysms. The mean concentrations of HVA, 5-HIAA and MOPEG in lumbar CSF was 469,275 and 39 pmol/l, respectively, whereas central CSF concentrations were 1,212, 499 and 48 pmol/ml, respectively. Compared to healthy controls, both HVA and 5-HIAA showed increased levels (pl 0,01) but MOPEG was within the normal range. No correlation between the concentrations of the monoamine metabolites, the neurological condition or the cerebral vascular diameter was observed in neither of the two groups. It is suggested that the accumulation of HVA and 5-HIAA in SAH patients is explained by a disturbance of the active transport mechanism.

Adult↗
PubMed1985

Visualisation of stereotactic radiolesions by nuclear magnetic resonance.

The ability to visualise stereotactic brain lesions produced by irradiation from the stereotactic Gamma Unit at the Karolinska Hospital was investigated. A patient who had undergone bilateral stereotactic gamma capsulotomy in two stages was examined by the nuclear magnetic resonance imaging technique, which demonstrated that the stereotactic lesions in the internal capsule could be visualised in the immediate postoperative period. This gives stereotactic radiosurgery a reliable anatomical basis and facilitates the planning and follow-up studies in this type of cerebral surgery.

Adult↗
PubMed1984

Controlled hypotension with adenosine in cerebral aneurysm surgery.

The cardiovascular effects of adenosine-induced controlled hypotension were studied in 10 patients undergoing cerebral aneurysm surgery. Adenosine and its metabolites were measured in arterial plasma using high-pressure liquid chromatography. Whole body and cerebral arteriovenous oxygen content differences (AVDO2), arterial lactate levels, and arteriojugular lactate differences were determined. In order to reduce the dose requirement of adenosine, the patients were pretreated with the adenosine uptake inhibitor, dipyridamole (0.3-0.4 mg . kg-1). During the infusion of adenosine (0.14 +/- 0.04 mg . kg-1 . min-1) the mean arterial blood pressure decreased by 43%, from 82 to 46 mmHg, during a mean hypotensive period of 32 min, without signs of tachyphylaxis. The arterial adenosine level increased from 0.15 +/- 0.02 to 2.45 +/- 0.65 microM (P less than 0.01). Hypotension was caused by a profound decrease in peripheral vascular resistance (61 +/- 3%, P less than 0.01), which was accompanied by an increase in cardiac output (44 +/- 9%, P less than 0.01). Heart rate increased moderately by 16 +/- 5% (P less than 0.01). Pulmonary vascular resistance and central venous pressures were unaffected. Arterial lactate and PaO2 were unchanged, while whole body oxygen consumption was decreased by 13 +/- 4% (P less than 0.05). The AVDO2 across the brain was decreased by 37 +/- 5% (P less than 0.05) without signs of lactate formation. The authors conclude that adenosine rapidly induces a stable and easily controlled hypotension in humans by dilation of arterial resistance vasculature.

Adenosine↗
PubMed1983

Effects of mannitol on blood volume and central hemodynamics in patients undergoing cerebral aneurysm surgery.

The effects on hemodynamics and blood volume of 500 ml of 20% mannitol administered intravenously in 15 min at the beginning of cerebral aneurysm surgery have been studied in 10 patients. Measurements were made before the infusion of mannitol (control) and at 15-min intervals for 1 hr. Control measurements showed normal hemodynamic data, while blood volume was lower than normal (P less than 0.001). Immediately after the mannitol infusion cardiac index (25%; P less than 0.01), pulmonary capillary wedge pressure (48%; P less than 0.001), and blood volume (43%; P less than 0.001) increased. Thirty minutes after the mannitol infusion, blood volume had returned to control levels, while the cardiac index and pulmonary capillary wedge pressure decreased 21% (P less than 0.01 and P less than 0.05, respectively) below control levels. Forty-five minutes after the mannitol infusion, serum osmolality and urine volume remained high. Our data confirm the presence of hypovolemia in patients with subarachnoid hemorrhage and a transient increase in blood volume associated with the infusion of mannitol. The data emphasize, however, that the hemodynamic response is biphasic, with an initial increase in pulmonary capillary wedge pressure and cardiac index, followed by a hypokinetic circulatory pattern with pulmonary capillary wedge pressure and cardiac index below control levels. The hypokinetic state occurred in spite of return of blood volume to control levels, suggesting that redistribution of blood from central to peripheral circulatory compartments had occurred.

Adult↗
PubMed1977

Bronchial asthma: some aspects of pathogenesis and therapy.

The first step in management of bronchial asthma is to exclude other diseases which may present as wheezing dyspena. Once the diagnosis is confirmed beyond a reasonable doubt, therapy can be initiated. Treatment depends on the type, severity, and duration of the disease. Other factors which dictate the choice of drug are the patient's response, metabolism of the drug, and complications of the disease. Theophylline forms the backbone of asthma therapy. Because of the wide variation in half-life of theophylline in different individuals due to variation in rate of metabolism and elimination, serum levels of theophylline should be monitored whenever possible. Newer antiasthmatic drugs, such as cromolyn sodium and inhaled steroids, are playing an increasing role in treatment of selected patients.

Acute Disease↗
PubMed1976

Exteroceptive influences on the lumbar back muscle tone and reflexes in the cat.

The exteroceptive influences on tonic activity and on stretch reflexes of the longissimus dorsi and multifidus spinae muscles were investiagted in decerebrate, spinal and chloralose-anesthetized cats. Adequate skin stimulation was used to map out facilitatory and inhibitory skin areas on the trunk and the extremities. On the trunk facilitatory areas are relatively large and located at the dorsal side while inhibitory areas are confined to the ventrolateral part of the contralateral body half. The facilitatory skin fields are of approximately the same size in decerebrate and spinal cats. On leg skin stimulation facilitation can be evoked from the ipsilateral hind limb while inhibition results from stimulation of the other limbs. Spinal cord transection increased excitatory effects of ipsilateral hind limb stimulation. Reflex responses in the back muscles to applied stretch are described. These reflexes were used as test reflexes in experiments with conditioning stimulation of the peripheral nerves supplying skin areas from which effects on back muscle activity were evoked by adequate stimulation. The conditioning-test experiments and those using adequate stimulation show that the longissimus dorsi and multifidus spinae are activated or facilitated by an ipsilateral stimulus to skin afferents. The extent of the effects induced by stimulation of skin differs in the types of preparation used. These differences may be accounted for by assuming a supraspinal control of the reflex pathways studied.

Anesthesia, General↗