| 61. |
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| 62. |
- Koskinen, Lars-Owe D., Professor, 1955-
(författare)
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The influence of bilateral electrical preganglionic sympathetic stimulation on intra- and extracranial blood flow.
- 1987
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 92:2, s. 185-192
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Tidskriftsartikel (refereegranskat)abstract
- The effects of bilateral electrical stimulation (SS) of the cervical sympathetic chain on intra- and extra cerebral blood flows were studied with the labelled microsphere method in the rabbit. Control blood flow was determined before the SS was started. The stimulation frequency was 7 Hz, the impulse duration 2 ms, the intensity 7 V and the stimulation time varied between 1 to 5 minutes before the second blood flow determination. Arterial blood gas values and blood pressure were unaffected by the stimulation. Due to the SS there were blood flow decrements in the extracranial tissues between 60-96%. The blood flow in the eyes, the dura, pineal gland and choroid plexa was markedly reduced during the SS. No obvious effect was elicited by the SS in the regional or total cerebral blood flow. The stimulation to control blood flow ratio ranged between 0.92 +/- 0.08 to 1.13 +/- 0.09 in different parts of the brain. The conclusions are that SS elicits vasoconstriction in several extra- and intracranial nonneuronal tissues and in the eye. Cerebral blood flow is not influenced by the SS.
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| 63. |
- Koskinen, Lars-Owe D., Professor, 1955-
(författare)
-
The influence of muscarinic and prostaglandic mechanisms on regional cerebral and peripheral blood flows and on the vascular effects of thyrotropin releasing hormone (TRH).
- 1994
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 152:4, s. 399-406
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Tidskriftsartikel (refereegranskat)abstract
- TRH has pronounced vascular effects. The final transmitter mechanisms of these effects are not fully understood. The present study was conducted in order to elucidate whether these effects are mediated by prostaglandic or muscarinic mechanisms. Muscarinic blockade augmented the vasoconstricting- and pressor effect of TRH; vasodilation in the brain was attenuated only in the caudate nucleus. Indomethacin provoked a decrease in regional cerebral blood flow and in the gastric mucosal blood flow. No effect of indomethacin was observed on the vascular effects of TRH. It is concluded that the cerebral vasodilating and peripheral vasoconstricting effects of TRH are not mediated by prostaglandins. Muscarinic mechanisms are involved in the vasodilating effect of TRH only in the caudate nucleus.
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| 64. |
- Koskinen, Lars-Owe D., Professor, 1955-, et al.
(författare)
-
The neuropeptide TRH has a minor effect on the enzymatic activity of acetylcholinesterase in vitro.
- 1998
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 19:10, s. 1675-1677
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Tidskriftsartikel (refereegranskat)abstract
- The neuropeptide thyrotropin-releasing hormone (TRH) elicits a variety of physiological effects of which some are due to cholinergic mechanisms. TRH modulates in vivo the effects of compounds affecting acetylcholinesterase (AChE). In the present study the in vitro effects of TRH on the activity of AChE were explored. TRH has no effect at physiologically relevant concentrations. At unphysiologically high concentrations (>5 mM) a slight inhibition was found. This was noticed also when the enzyme was exposed to the amide-free tripeptide analog p-Glu-His-Pro. We conclude that any cholinergic effect of TRH observed in vivo is unlikely to be due to a direct interaction of the peptide with AChE.
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| 65. |
- Koskinen, Lars-Owe D., Professor, 1955-, et al.
(författare)
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Thyrotropin-releasing hormone (TRH) causes sympathetic activation and cerebral vasodilation in the rabbit.
- 1984
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 122:2, s. 127-136
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Tidskriftsartikel (refereegranskat)abstract
- The effects of TRH on regional blood flow were studied in rabbits under urethane anesthesia. Four types of experiments were performed with the following results. (1) I.v. injection of 2 mg/kg b.w. TRH in animals with unilateral cervical sympathotomy caused a rise in mean arterial blood pressure from 10.0 +/- 0.5 to 13.3 +/- 0.5 kPa. Total cerebral blood flow, measured with labeled microspheres, increased from 75 +/- 5 to 126 +/- 16 g/min/100 g tissue on the intact side. There was a similar increase on the side with sympathotomy. The greatest increase, about 70%, was observed in cortical gray matter, caudate nucleus and thalamic region. There were marked reductions in blood flows in the spleen, gastric mucosa, skin and skeletal muscle. Mydriasis occurred on the side with an intact sympathetic supply. (2) I.v. infusion of 0.06 mg/kg b.w. per min TRH in animals with unilateral cervical sympathotomy and stabilized blood pressure increased total cerebral blood flow from 84 +/- 10 to 139 +/- 7 g/min/100 g. Blood flows to the masseter muscle, submandibular gland and facial skin but not to the eye or tongue were markedly reduced on the side with an intact sympathetic supply while little or no effect was observed on the side with sympathotomy. (3) Unilateral peripheral stimulation of the sympathetic chain at 1 Hz after bilateral sympathotomy caused a reduction in blood flows in the tongue, masseter muscle, submandibular gland and facial skin in animals with stabilized blood pressure. No potentiation of the stimulation effect was observed during TRH infusion. (4) The arteriovenous difference in oxygen saturation in the brain decreased from 39.1 +/- 2.8 to 26.4 +/- 3.7% after i.v. injection of 2 mg/kg b.w. TRH. The results indicate that TRH caused cerebral vasodilation in excess of that required by possible changes in cerebral metabolism. The vasoconstriction in the head region and the mydriasis was caused mainly by an increase in the activity of the cervical sympathetic nerves.
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| 66. |
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| 67. |
- Larsson, Jan, et al.
(författare)
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Effects of TRH and atropine on induction and duration of anesthesia with propofol in rats.
- 1996
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 17:2, s. 293-297
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Tidskriftsartikel (refereegranskat)abstract
- The effects of IV TRH pretreatment on induction of anesthesia with propofol or pentobarbital were investigated in rats. The effects of IV TRH, administered after induction, on duration of propofol anesthesia and the interaction with atropine were also studied. The doses of propofol or pentobarbital were not influenced by TRH. TRH reduced duration of anesthesia after propofol, with higher brain concentrations of propofol at recovery. Atropine did not block this effect, but given alone prolonged duration of anesthesia. It is concluded that TRH shortens the duration of propofol anesthesia, probably due to a pharmacodynamic effect and not to a pharmacokinetic interaction.
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| 68. |
- Lindvall, Peter, et al.
(författare)
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Intracranial Hypertension due to Cerebral Venous Sinus Thrombosis following Head Trauma : A Report of Two Cases.
- 2013
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Ingår i: Case Reports in Neurology. - : S. Karger AG. - 1662-680X. ; 5:3, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral venous sinus thrombosis (CVST) may occur following head trauma and contribute to intracranial hypertension that mandates immediate action. Anticoagulant therapy is the first line of treatment in CVST but may not be applicable in patients with head trauma. Here, we report on the treatment of 2 patients with CVST. In 1 patient, there was an attempt to perform thrombectomy and thrombolysis, and eventually a decompressive craniectomy was performed. In this patient, there was an excellent outcome. In the other patient, an immediate decompressive craniectomy was performed that did not improve the outcome.
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| 69. |
- Lundkvist, B., et al.
(författare)
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An adjustable CSF shunt : advices for clinical use
- 2003
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Ingår i: Acta Neurologica Scandinavica. - : Wiley-Blackwell. - 0001-6314 .- 1600-0404. ; 108:1, s. 38-42
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The opening pressure and the resistance of a CSF shunt are essential for clinical use in order to set the proper opening pressure and to determine the shunt function in vivo. We find it of vital importance to validate and supplement the product description given by the manufacturer. The in vitro properties of a newly introduced, adjustable differential pressure valve with a siphon-preventing device (Strata valve) was compared with its predecessor (Delta valve).METHODS: An automated, computerized experimental set-up based on regulation of pressure, built into an incubator at 37 degrees C, was used. Opening pressure, resistance and siphon preventing properties were determined. Six brand-new shunts of each type with catheters were tested. The Delta valves were at a performance level of 1.5.RESULTS: The hydrodynamic properties of the Strata and Delta valves were similar. The anti-siphoning device was functioning for all valves. The estimated mean resistance for Delta and Strata shunts was 2.6 +/- 0.4 and 2.2 +/- 1.0 mmHg/ml/min, respectively. The mean opening pressure for the five performance levels of the Strata shunt are: 3.3, 5.1, 7.7, 10.7 and 13.1 mmHg. There may however, be considerable variations between the shunts.CONCLUSIONS: The Strata shunt is a properly working adjustable valve with anti-siphoning device that showed good reproducibility concerning opening pressure and resistance. At performance level 1.5, the new Strata shunt was similar to its predecessor concerning opening pressure and resistance. The given values of the different opening pressures and resistance could be used for in vivo testing of the valve function with a standard lumbar CSF infusion test.
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| 70. |
- Magnusson, Beatrice M., et al.
(författare)
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A prospective observational cohort study of traumatic brain injury in the northern region of Sweden
- 2022
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Ingår i: Brain Injury. - : Taylor & Francis. - 0269-9052 .- 1362-301X. ; 36:2, s. 191-198
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Generally, to map epidemiological and demographic features of patients with traumatic brain injury (TBI) in Umeå county, Sweden. Specifically, to evaluate the subjects needing a computed tomography (CT) of the head after suffering from TBI and frequencies of 1) intracranial lesions detected with CT, 2) need for neurosurgical intervention and 3) admission to hospital.METHODS: Patients with a suspected TBI, undergoing CT within 24 hours of arrival to hospital, were included in a database for evaluation.RESULTS: Out of 302 patients (63% male), 83% were GCS 13-15, 7% were GCS 9-12 and 10% were GCS <9. The frequency of abnormal CT findings was 23% in GCS 13-15, 67% in GCS 9-12 and 97% in GCS <9. Neurosurgical intervention was needed by 4% of those with GCS 13-15, 52% of those with GCS 9-12 and by 76% of those with GCS <9.CONCLUSIONS: Subjects with GCS 13-15 had higher frequencies of abnormal CT findings, need for neurosurgical intervention and hospital admission than previously reported. A similar trend was observed for patients with GCS 9-12, which can be of serious nature, with a higher frequency of need for neurosurgical intervention than previously described.
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