Pathology of myocardial infarction

Myocardial infarction (MI) is an increasing problem, worldwide. An appreciation of its causes and morphology helps provide a basis for development of new interventions, as well as its management, and in the future prevention. Studies have shown that the myocardium does not suffer sudden and complete permanent damage, but rather that it takes time for the damage to start and to progress. It is this interval that is used to salvage myocardium, post ischaemic myocardial events, thus improving patient outcomes. This paper discusses the morphological findings at different time points and illustrates them.     

Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste

Objectives

The aim of the study was to clinically and histologically evaluate the healing of human intrabony defects treated with open flap surgery (OFD) and application of a new, resorbable, fully synthetic, unsintered, nanocrystalline, phase-pure hydroxyapatite (nano-HA).

Materials and methods

Six patients, each of them displaying very advanced intrabony defects around teeth scheduled for extraction due to advanced chronic periodontitis and further prosthodontic considerations, were included in the study. Following local anaesthesia, mucoperiosteal flaps were reflected; the granulation tissue was removed, and the roots were meticulously debrided by hand and ultrasonic instruments. A notch was placed at the most apical extent of the calculus present on the root surface or at the most apical part of the defect (if no calculus was present) in order to serve as a reference for the histological evaluation. Following defect fill with nano-HA, the flaps were sutured by means of mattress sutures to allow primary intention healing. At 7 months after regenerative surgery, the teeth were extracted together with some of their surrounding soft and hard tissues and processed for histological analysis.

Results

The postoperative healing was uneventful in all cases. At 7 months following surgery, mean PPD reduction and mean CAL gain measured 4.0?±?0.8 and 2.5?±?0.8 mm, respectively. The histological analysis revealed a healing predominantly characterized by epithelial downgrowth. Limited formation of new cementum with inserting connective tissue fibers and bone regeneration occurred in three out of the six biopsies (i.e. 0–0.86 and 0–1.33 mm, respectively). Complete resorption of the nano-HA was found in four out of the six biopsies. A few remnants of the graft particles (either surrounded by newly formed mineralized tissue or encapsulated in connective tissue) were found in two out of the six biopsies.

Conclusion

Within their limits, the present results indicate that nano-HA has limited potential to promote periodontal regeneration in human intrabony defects.

Clinical relevance

The clinical outcomes obtained following surgery with OFD?+?nano-HA may not reflect true periodontal regeneration.     

Peculiarities of vasomotor reaction of cerebral vessels in arterial hypertension

We studied vasomotor activity of rat cerebral vessels. Peculiarities of endothelium-dependent reactions of cerebral arteries in induced arterial hypertension were revealed. Quantitative and qualitative relationships between the parameters of the vasomotor apparatus of cerebral arteries and parameters of circulatory homeostasis were determined. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 7, pp. 36–38, July, 2007     

Interleukin-6 enhances growth factor-dependent proliferation of the blast cells of acute myeloblastic leukemia

The effects of recombinant interleukin-6 (IL-6) on the proliferation of blast precursors present in the peripheral blood of patients with acute myeloblastic leukemia (AML) was investigated. IL-6 had little effect by itself; however, it synergized with granulocyte macrophage colony- stimulating factor (GM-CSF) and interleukin-3 (IL-3) in the stimulation of AML blast colony formation. Responsiveness of blast progenitors to IL-6 was heterogeneous. On normal bone marrow cells the same synergy was observed on granulocyte and monocyte precursors (GM-CFC), while there was no significant effect on erythroid and multipotential precursors.