Focal ischemia of the rat brain,with special reference to the influence of plasma glucose concentration

Summary Focal cerebral ischemia was induced by occlusion of the right middle cerebral artery in hypoglycemic, normoglycemic, as well as in acute and chronic diabetic rats. The brain damage was studied after 4 days. The volume of infarction was decreased in hypoglycemia (29±19 mm³ (mean±SD) versus 58±35 mm³,P<0.0046), unaltered in acute diabetes (61±45 mm³), and increased in chronic diabetes (91±22 mm³,P<0.0463). The cortex adjacent to the infarct showed selective neuronal injury affecting the cortical layers 2 and 3. The damage was enhanced by hypoglycemia and prevented in most of the diabetic animals. The findings indicate that different mechanisms cause infarction and selective neuronal injury outside infarcts, but that both are influenced by the plasma glucose concentration.     

Release of 3H-5-Hydroxytryptamine from Isolated Rabbit Aorta

Abstract: The main aim of the present investigation was to study systematically the passive and stimulation-evoked release of ³H-5-hydroxytryptamine (³H-5-HT) from rabbit isolated aorta. This was accomplished by preloading rings of aorta with ³H-5-HT (10^–6M) and then monitoring by fractional collection the basal ³H-outflow and stimulation-evoked ³H-overflow. The basal ³H-outflow from aorta preloaded with 10^–6M of either ³H-5-HT or (-)-³H-noradrenaline (³H-NA) leveled off about 100 min. after the onset of wash-out and remained almost constant thereafter (100–240 min.). The basal ³H-outflow from tissue preloaded with ³H-5-HT was almost 3-fold higher (70–240 min.) than that seen after preloading with ³H-NA. Cocaine (3x10^–5M) did not alter the basal ³H-outflow (15–240 min.) from tissue preloaded with ³H-5-HT, while pargyline (5X10^–4M) decreased it by about 66% (100–240 min.). Electrical-field stimulation (S₁S₇, 200 mA, 600 pulses, 0.5 msec, 3 Hz) were applied to the tissue. The initial stimulation-evoked ₃H-overflow from aorta preloaded with ³H-5-HT was higher than the subsequent ones (S₁-S₇: 100, 35, 35, 35, 35, 37, and 40%). Similar results to these were obtained with tissues preloaded with ³H-NA. The stimulation (S₁-S₇; 200 mA; 600 pulses, 0.5 msec, 3 Hz)-evoked ³H-overflow increased in an apparent linear manner with the amount of current used (50–200 mA). This was also the case for number of pulses (100–900) in the stimulus. The stimulation-evoked ³H-overflow depended in part on the stimulation frequency: unchanged at 2–4 Hz; small increase at 8 Hz; and a 15-fold increase at 16 Hz relative to 2 Hz. Tetrodotoxin (10^–6M) decreased the stimulation-evoked ³H-overflow from aorta preloaded with ³H-5-HT (S₂-S₆) by about 60%, while S₁ was not affected. The inhibitory effect of tetrodotoxin was fully reversed by washing the aorta with drug-free salt solution. Omission of Ca²⁺ from the salt solution reduced the stimulation ³H-overflow by 47–57% (S₂-S₆) while S₁ was unaffected. 6-Hydroxydopamine markedly increased the stimulation-evoked ³H-overflow from ³H-5-HT preloaded rings (180–323% of control). Pargyline (5x10^–4M), cocaine (3x10^–5M) and removal of endothelium did not alter the stimulation-evoked ³H-overflow evoked by stimulation (S₁-S₆) of aorta preloaded with ³H-5-HT. It is concluded that ³H-5-HT can be released by electrical-field stimulation as a “false transmitter'’from rabbit isolated aorta. Most of the release is probably of neuronal origin. However, some of the stimulation-evoked ³H-overflow is derived from extraneuronal sites.     

Presynaptic action of adrenaline on adrenoceptors modulating stimulation-evoked 3H-noradrenaline release from rabbit isolated aorta

Summary The purpose of this investigation was to study the effect of adrenaline on presynaptic adrenoceptors by recording the release of ³H-noradrenaline evoked by electrical-field stimulation. Adrenaline (10^–10–³ × 10^–9 mol/l) had no effect on the ³H-overflow evoked by stimulation of aorta preloaded with ³H-noradrenaline. At 10^–8 and 3 × 10^–8 mol/l, the ³H-overflow was decreased by up to 47%. The maximum decrease was more marked in the presence of either cocaine (3 × 10^–5 mol/l) plus corticosterone (4 × 10^–5 mol/l), cocaine (3.3 × 10^–6 mol/l) plus normetanephrine (4 × 10^–5 mol/l), or desipramine (10^–6 mol/l) plus normetanephrine (10^–5 mol/l). The relationship between adrenaline-induced decrease and stimulation-frequency was dependent on the experimental design: either the decrease was the same at all frequencies (1–16 Hz) or it was more marked, the lower the frequency (1 > 3 > 8 Hz). Phentolamine and rauwolscine (both 10^–6 mol/l) antagonized the inhibitory effect of adrenaline (10 ^{– 8}–10^–6 mol/l). Phenoxybenzamine (10^–6 mol/l), prevented the inhibitory effect. No enhancing effect of adrenaline (10^–9–10^–6 mol/l) was observed in the presence of these three -adrenoceptor antagonists. Our results suggest that adrenaline activates inhibitory ₂-adrenoceptors, but not facilitatory -adrenoceptors on postganglionic sympathetic nerve terminals in rabbit aorta. Send offprint requests to J. Abrahamsen at the above address     

The 'novel' 'uncoupling' proteins UCP2 and UCP3: what do they really do? Pros and cons for suggested functions

The scientifically novel, but evolutionarily ancient, so-called uncoupling proteins 2 and 3 (UCP2, UCP3) are structurally similar to the archetypical uncoupling protein UCP1. A series of suggestions have been forwarded for their physiological function. We discuss systematically here the pros and cons for these suggestions. We conclude that the novel UCPs do not seem to be physiologically relevant uncoupling proteins; the uncoupling property was apparently a late introduction into the subfamily through the evolution of UCP1. Physiological functions ascribed to UCP2 and UCP3 based on their purported uncoupling property may have to be revised (i.e. any type of thermogenesis, including protection against obesity, protection against the formation of reactive oxygen species and thermogenic involvement in the fever response). The presence of a mixed genetic background in most published studies of UCP2 or UCP3 gene-ablated mice also means that data concerning marked differences in diabetes propensity, infection sensitivity and production of reactive oxygen species may require confirmation in backcrossed mice. The increased expression of UCP2 and UCP3 under conditions of increased fatty acid metabolism implies an as yet undefined role in lipid metabolism. Thus, the novel UCPs should probably be considered as mitochondrial carriers, and the challenge now is to identify the transported molecule.     

Cell density in the border zone around old small human brain infarcts

Nine brain autopsy cases of small old cerebral infarcts were selected for neuropathological studies. Eight of the patients had cortical infarcts, in two cases with extension into the striate body. In one case the infarct involved the striate body only. The density of neurons and glial cells was measured in the coronal and the horizontal planes at various distances from the margin of the infarct. Corresponding counting points in the contralateral hemisphere served as control. On light microscopy, the infarcted cortex was irregularly shaped, but on serial sections the bulging parts appeared to be cut off from the infarcted tissue ("pseudo-infarct islands"). The zone of transition from infarcted to normal brain tissue was less than a few mm wide. In one patient, tomographic measurements of the cerebral blood flow (CBF) and a CT scan could be compared with the neuropathological findings. In this patient, CBF in the surroundings of the infarct was decreased despite a normal neuronal density. The study supports the traditional view held by pathologists that a sharp transition exists between infarcted and normal brain tissue and suggests that the hypoperfusion zone surrounding the region of complete infarction may be due to mechanisms other than selective loss of neurons.     

Lack of presynaptic modulation by isoprenaline of 3H-noradrenaline release from rabbit isolated ear artery

Summary The aim of the present investigation was to examine whether or not presynaptic facilitatory -adrenoceptors are detectable on the postganglionic nerves in the rabbit isolated ear artery. Strips of rabbit central ear artery were incubated with ³H-noradrenaline (10^–7 mol/l; 30 min or 10^–6 mol/l; 60 min). Subsequently, they were washed repeatedly with physiological salt solution. The strips were subjected to electrical-field stimulation (S₁–S₈) and the resultant ³H-overflow was determined.When the ear artery was stimulated with 150 pulses (0.5 ms; 3 Hz; 225 mA), isoprenaline (10^–9–10^–6 mol/l) either alone or in the presence of either rauwolscine (10^–6 mol/l) or phentolamine (10^–6 mol/l) did not alter the stimulation-evoked ³H-overflow. This was also the case in the presence of rauwolscine (10^–6 mol/l) plus either the selective phosphodiesterase inhibitor ICI 63 197 (3 × 10^–5 mol/l) or forskolin (10^–6 mol/l). When the ear artery was stimulated with 300 pulses (1 ms; 5 Hz; 225 mA), isoprenaline had no effect on the stimulation-evoked ³H-overflow. This was also the case when phentolamine (10^–6 mol/l) was present. Propranolol (10^–7–10^–5 mol/l) did not alter the stimulation-evoked ³H-overflow. In some experiments, the stimulation current was reduced to 175 mA in order to obtain similar reference release (S₃) values despite the presence of rauwolscine (150 pulses; 0.5 ms; 3 Hz). Even then, isoprenaline (10^–9–10^–6 mol/l) did not change stimulation-evoked ³H-overflow. The results suggest that postganglionic sympathetic nerves in rabbit central ear artery do not possess presynaptic facilitatory -adrenoceptors. Send offprint requests to J. Abrahamsen at the above address     

The prognostic value of polycomb group protein B‐cell‐specific moloney murine leukemia virus insertion site 1 in stage II colon cancer patients

The aim of this study was to investigate the prognostic value of B‐cell‐specific moloney murine leukemia virus insertion site 1 (BMI1) protein expression in primary tumors of stage II colon cancer patients. BMI1 protein expression was assessed by immunohistochemistry in a retrospective patient cohort consisting of 144 stage II colon cancer patients. BMI1 expression at the invasive front of the primary tumors correlated with mismatch repair status of the tumors. Furthermore, BMI1 expression at the luminal surface correlated with T‐stage, tumor location, and the histological subtypes of the tumors. In a univariate Cox proportional hazard analysis, no statistical significant association between risk of relapse and BMI1 protein expression at the invasive front (HR: 1.12; 95% CI 0.78–1.60; p = 0.53) or at the luminal surface of the tumor (HR: 1.06; 95% CI 0.75–1.48; p = 0.70) was found. Likewise, there was no association between 5‐year overall survival and BMI1 expression at the invasive front (HR: 1.12; 95% CI 0.80–1.56; p = 0.46) or at the luminal surface of the tumor (HR: 1.16; 95% CI 0.86–1.60; p = 0.33). In conclusion, BMI1 expression in primary tumors of stage II colon cancer patients could not predict relapse or overall survival of the patients, thus having a limited prognostic value in stage II colon cancer patients.     

Superior fixation and less periprosthetic stress-shielding of tibial components with a finned stem versus an I-beam block stem: a randomized RSA and DXA study with minimum 5 years’ follow-up

Background and purpose — The stem on the tibial component of total knee arthroplasty provides mechanical resistance to lift-off, shear forces, and torque. We compared tibial components with finned stems (FS) and I-beam block stems (IS) to assess differences in implant migration.

Patients and methods — In a patient-blinded RCT, 54 patients/knees (15 men) with knee osteoarthritis at a mean age of 77 years (70–90) were randomly allocated to receive tibial components with either a FS (n = 27) or an IS (n = 27). Through 5 to 7 years’ follow-up, implant migration was measured with RSA, periprosthetic bone mineral density (BMD) was measured with DXA, and surgeons reported American Knee Society Score (AKSS).

Results — At minimum 5 years’ follow-up, maximum total point motion (MTPM) was higher (p = 0.04) for IS (1.48?mm, 95% CI 0.81–2.16) than for FS (0.85?mm, CI 0.38–1.32) tibial components. Likewise, total rotation (TR) was higher (p = 0.03) for IS (1.51?, CI 0.78–2.24) than for FS (0.81?, CI 0.36–1.27). Tibial components with IS externally rotated 0.50° (CI –0.06 to 1.06) while FS internally rotated 0.09° (CI –0.20 to 0.38) (p = 0.03). Periprosthetic bone stress-shielding was higher (p < 0.01) up to 2 years’ follow-up for IS compared with FS in the regions medial to the stem (–13% vs. –2%) and posterior to the stem (–13% vs. –2%). Below the stem bone loss was also higher (p = 0.01) for IS compared with FS (–6% vs. +1%) up to 1-year follow-up. Knee score improved similarly in both groups up to 5 years’ follow-up.

Interpretation — Periprosthetic bone stress-shielding medial and posterior to the stem until 2 years, and tibial component migration at 5 years, was less for a finned compared with an I-shaped block stem design.

Trial registration: ClinicalTrials.gov identifier: NCT00175136.     

HE4 as a predictor of adjuvant chemotherapy resistance and survival in patients with epithelial ovarian cancer

The aim of this study was to investigate the value of serum human epididymis protein 4 (HE4) and HE4 tissue protein expression to predict tumor resistance to adjuvant chemotherapy, progression‐free survival (PFS), and overall survival in patients with epithelial ovarian cancer (EOC). Consecutive inclusion of 198 patients diagnosed with EOC was conducted. Blood samples were collected prior to surgery and tissue samples during surgery. Patient data were registered prospectively in the Danish Gynecologic Cancer Database. The association between serum HE4 and HE4 tissue protein expression, resistance to adjuvant chemotherapy, PFS, and overall survival were analyzed in univariate analyses and in multivariate analyses adjusted for age, performance score, surgical outcome, stage, grade, and histological subtype. Serum HE4 levels predicted chemotherapy resistance, PFS, and overall survival correlated significantly (p < 0.001) in the univariate analyses; but after adjustment in a multivariate model, serum HE4 was insignificant, except in a subgroup analysis of postmenopausal women, where serum HE4 significantly predicted resistance to chemotherapy and progression‐free survival. HE4 tissue protein expression predicted PFS (p = 0.022) and overall survival (p = 0.047) in the univariate analysis, while HE4 tissue protein expression failed to predict these outcomes in the adjusted multivariate analyses. Serum HE4 or HE4 tissue protein expression are not independent factors of chemotherapy resistance or survival in patients with EOC, but serum HE4 might predict chemotherapy resistance and PFS in postmenopausal women.