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Biomedical subjects

M Broberg

Publications and source records attributed to M Broberg.

12 recordsLinked to original sources
PubMed2006

Cell swelling, seizures and spreading depression: an impedance study.

The cellular processes that take place during the transition from pre-seizure state to seizure remain to be defined. In this study in awake, paralyzed rats, we used an electrical impedance measure of changes in extra-cellular intracranial volume to estimate changes in cell size in acute models of epilepsy. Animals were prepared with extradural electroencephalographic (EEG)/impedance electrodes and a venous catheter. On a subsequent day, animals were paralyzed, ventilated and treated with picrotoxin, kainic acid or fluorocitrate in doses that usually induce epileptiform discharges. We now report that increases in baseline impedance were induced by kainic acid and smaller increases by picrotoxin. We also demonstrated that epileptiform discharges were preceded by small, accelerated increases in impedance. Increases in baseline impedance were highly correlated with increases in power of non-ictal high frequency EEG activity. Seizures were accompanied by increases in impedance and all treatments induced transient, relatively large, increases in impedance often associated with unilateral reductions in low frequency EEG, likely periods of spreading depression. We conclude: cerebral cells swell in convulsant models of epilepsy, that there are pre-ictal accelerations in cell swelling, and that spreading depression-like events are frequently associated with seizures.

Action Potentials↗
PubMed2004

Localised astroglial dysfunction disrupts high-frequency EEG rhythms.

We used cerebral cortex injections of fluorocitrate to determine if selective astrocytic disturbances affect the electroencephalogram (EEG). Rats were halothane-anaesthetized and 0.8 nmol of sodium fluorocitrate was injected into hindlimb (motor-sensory) cortex. Extra-dural EEG electrodes were implanted after which the anaesthesia was ceased. EEG was recorded at 1, 3, 5, 7, 24 and 48 hours. There was a broad-band reduction in frequencies in the EEG between 20 and 100 Hz commencing within 1 hour of injection and largely restricted to the side of injection and to frontal cortex, and maximal at 3 hours. Halothane had a suppressive effect on gamma power after citrate injection, but also prevented EEG suppression caused by fluorocitrate, consistent with the hypothesis that some of the action of fluorocitrate depended on gap-junctions. The findings are consistent with the hypothesis that primary astroglial dysfunction leads to reduced neuronal transmission and further supports gap-junctions as mediating fluorocitrate-induced astroglial effects.

Animals↗
PubMed2001

Von Willebrand factor, a key protein in the exposure of CD62P on platelets.

When a biomaterial is introduced into the body water, electrolytes, and proteins adsorb to the surface. Platelets are then the first cells to interact with the surface adsorbed protein layer. We have studied the role of von Willebrand factor (vWF) for platelet-protein interaction by measuring different platelet responses to protein- and plasma-coated hydrophobic glass surfaces. A high exposure of CD62P on the platelet surface was seen after 10 min of incubation on platelets interacting with vWF and normal plasma-coated surfaces (79 and 67%, respectively). On the surfaces coated with albumin and factor VIII deficient plasma, the exposure was low (11 and 27%, respectively). A higher formation of filipodial extensions on the platelets was seen on the surfaces coated with vWF and normal plasma than on the surfaces coated with albumin or factor VIII deficient plasma. No significant differences were seen between the surfaces regarding the platelet release of PF4, ATP, or phospholipids. As shown by these results, vWF is a specific regulator of the exposure of CD62P by platelets and hence important for the interaction between platelets and later arriving neutrophils at biomaterial surfaces.

Adenosine Triphosphate↗
PubMed2001

The respiratory burst response of surface-adhering leukocytes. A key to tissue engineering.

Biomaterials implanted into tissue will participate in the complex signalling between cells during wound healing. Recent studies have revealed that crucial cellular signalling pathways are regulated by the extra- and intracellular redox states and that reactive oxygen species function as intercellular signal molecules. Biomaterials have been shown to affect the respiratory burst response of surface-adhering leukocytes, thus interfering with major regulatory functions of cells also in surrounding tissues. The respiratory burst of surface-adhering leukocytes may thus be a key event in the understanding of biomaterial interaction with tissues, and the aim of this review is to highlight this field of research.

Journal Article↗
PubMed1998

Specific activation of platelets by surface-adsorbed plasma proteins.

Platelets were isolated from human blood by Percoll density gradient centrifugation in a low Ca2+/high Mg2+ buffer. The buffer reversibly inactivates the cells during separation. The purity of the isolated cells (> 99%) was determined by flow cytometry, their viability was confirmed by fluorescein diacetate hydrolysis, and their morphology was studied with TEM. Plasma proteins were adsorbed onto hydrophobic glass surface, and pure platelets were added and incubated for up to 30 min at 37 degree C. Platelet activation was determined by cell spreading, formation of microparticles and surface exposure of CD62P indicating the release of alpha-granules. Surface-immobilized IgG was shown to cause the release of microparticles and cell lysis, in accordance with data published by others. Surface-immobilized vWF was shown to induce CD62P exposure on the platelet cell surface. The specificity of this response was demonstrated by adsorbing plasma proteins from normal and factor VIII-deficient plasma.

Blood Platelets↗
PubMed1998

Criminal multilation of the human body in Sweden--a thirty-year medico-legal and forensic psychiatric study.

During the 30-year period 1961-1990, a total of 22 deaths with criminal multilation/dismemberment of the human body were registered in Sweden. The multilations occurred in time clusters, mostly during the summer and winter periods, and increased during the three decades, with incidence rates of 0.05, 0.1, and 0.125 per million inhabitants and year, respectively. Multilation was noted 6.6 times more often in large urban areas than in the rest of Sweden. Defensive mutilation, in order to get rid of the corpse or make its identity more difficult, was noted in ten instances, aggressive mutilation following outrageous overkilling in four, offensive mutilation (lust murder) in seven, and necromanic multilation in one instance. In the last-mentioned case the cause of death was natural, while all deaths in the first three groups were homicidal, or homicide was strongly suspected. All perpetrators were males, in six instances assisted by other persons. In more than half of the cases the perpetrator's occupation was associated with application of anatomical knowledge, e.g., butcher, physician, veterinary assistant, or hunter. The perpetrators of the defensive and aggressive mutilations were mostly disorganized, i.e., alcoholics or drug users with previous psychiatric contacts and criminal histories, while the lust murderers were mostly organized, with a history of violent crimes (including the "serial killing" type), drug abuse and mental disorders with anxiety and schizophrenia, in that order to a diminishing degree. There were differences in mode of mutilation, depending on whether the mutilation was carried out by a layman, a butcher, or a physician. In only one case was the perpetrator convicted for the mutilation act itself; in the remaining instances the manslaughter, as a more serious crime, assimilated the mutilation. When the mutilation made it impossible to establish the cause of death, the perpetrators, despite strong circumstantial evidence indicating murder, were acquitted.

Adolescent↗
PubMed1996

Sun-related behaviour in individuals with dysplastic naevus syndrome.

In Sweden, individuals with dysplastic naevus syndrome are regularly screened and informed about self-examination and sun-protection at special clinics. This study describes sun-related behaviour in this group. A total of 54/65 consecutive patients with dysplastic naevus syndrome (28 women and 26 men) completed diary recordings of sun-related behaviour during 1 month in 1994. A majority (81%) reported sunbathing with the intention to get a tan, mean number of occasions 9.2, range 1-24 occasions, during the month of recordings. Out of these, 61% reported sunburns, some of them repeatedly up to 7 times. Sunbathing occurred mainly in bathing suits during midday in sunny weather, with a mean duration of 2.5 h per occasion. Such a hazardous behaviour in the sun in a melanoma high risk group is alarming. New models for intervention to support a more sun protective life style in this group of patient have to be elaborated.

Adolescent↗
PubMed1991

Early detection and prevention of cutaneous malignant melanoma: emphasis on Swedish activities.

The incidence of cutaneous malignant melanoma has increased more than the incidence of any other malignant tumour disease in Sweden the last three decades. Parallel to the almost 6% annual increase in incidence there has been a 3% annual increase in mortality. The knowledge of significant risk factors for melanoma (intermittent sun exposure and phenotypic traits related to skin pigmentation and propensity for dysplastic nevi) as well as the relationship between thin tumours and a good prognosis has been used to develop strategies for primary and secondary prevention. In this paper the Swedish programs for education of physicians, nurses and the general population are presented. A nationwide program for the identification and follow-up of individuals with dysplastic nevus syndrome has been initiated. The effects of the programs are followed by population-based melanoma registries.

Humans↗