Decreased interstitial glucose and transmural gradient in lactate during ischemia

Summary The purpose of this investigation was to assess the effects of ischemia and reperfusion on the transmural levels of glucose and lactate in the interstitium in 11 open-chest swine. Microdialysis probes were used to estimate changes in interstitial metabolities across the ventricular wall. Probes were placed in the subepicardium and the subendocardium of the left anterior descending (LAD) coronary artery perfusion bed and in the midmyocardium of the circumflex (CFX) perfusion bed. The LAD coronary artery was cannulated and perfused with blood from the femoral artery through an extracorporal perfusion circuit. Ischemia was induced in the LAD perfusion bed by reducing the flow of the LAD perfusion pump by 60% for 50 min, and was followed by 30 min of reperfusion. Regional myocardial blood flow was assessed with fluorescent microspheres. Ischemia resulted in a transmural gradient in blood flow, with the most severe reduction in flow occurring in the subendocardium (p<0.05). We found a significant reduction in interstitial glucose in both the LAD subepicardium (1.26±0.24 mM) (p=0.0009) and subendocardium (0.89±0.21 mM) (p=0.0001) during ischemia compared to the aerobic (non-ischemic) period (1.97±0.25 mM, 2.03±0.29 mM for the subepicardium and subendocardium, respectively). This coincided with a significant reduction in glucose delivery (LAD pump flow^* arterial glucose) to the LAD perfusion bed during ischemia (54.5±8.5 mol/min) compared to aerobic values (182.1±25.3 mol/min) (p<0.05). Interstitial lactate levels were significantly increased during ischemia in the LAD subendocardium (3.39±0.46 mM) compared to the aerobic values (1.73±0.46 mM) (p<0.0029). A transmural gradient in interstitial lactate levels was observed during ischemia: this gradient was not seen during the aerobic period and was negated upon reperfusion. In conclusion, ischemia resulted in a decrease in interstitial glucose in both the LAD subepicardium and subendocardium, and an increase in interstitial lactate in the LAD subendocardium. Further, a transmural gradient in interstitial lactate levels was observed during ischemia, with the highest lactate values appearing in the subendocardium.     

Immunophenotypic and DNA content characteristics of plasma cells in multiple myeloma and monoclonal gammopathy of undetermined significance

In the present paper we review the immunophenotypic characteristics of plasma cells (PC) and the PC DNA contents from multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS), and its value for the differential diagnosis between both entities. The strong reactivity for CD38 and the positivity for CD138 are the two best markers for identifying PC. Myelomatous PC display an heterogeneous phenotype consistent with the fact that the neoplastic clone is able to undergo a certain degree of differentiation. In addition, PC from MM patients usually lack surface expression of B-cell associated antigens and frequently display reactivity for markers which are not restricted to the B-cell lineage. In MGUS patients, two clearly defined and distinct PC subpopulations can be identified. One of these PC subpopulations shows phenotypic characteristics identical to those of normal PC, including a very strong reactivity for the CD38 antigen, intermediate/low light scatter characteristics and positivity for CD19, in the absence of CD56, and corresponds to the residual normal bone marrow PC. The second PC subpopulation shows an immunophenotype similar to that of myelomatous PC, characterized by a slightly lower reactivity for CD38 and strong CD56 expression, on the absence of positivity for CD19, these PC corresponding to the clonal counterpart. Using a simultaneous staining for PC and DNA, around 60% of MM and 73% of MGUS patients display DNA aneuploidy, the majority of them being hyperdiploid. However, in contrast to MM patients, in MGUS patients two clearly different PC subsets can be discriminated in most cases (73%): a diploid and an aneuploid (hyperdiploid) subset, corresponding to normal and clonal PC, respectively. Upon comparing hyperdiploid with diploid patients in MM, the former display a better prognosis, in line with the higher incidence of DNA hyperdiploidy in MGUS. A clear correlation between the percentage of S-phase PC and several prognosis features of MM has been found. In spite of these findings, no significant differences in the percentage of pathological S-phase PC are detected between MM and MGUS patients. Regarding the differential diagnosis between MGUS and MM, multivariate analysis shows that the ratio between the number of clonal and normal residual PC is the best single parameter.     

Breast Carcinoma in Childhood and Adolescence: Case Report and Review of the Literature

Secretory breast carcinoma is a rare tumor originally described in children and adolescent women with a characteristic morphology and a controversial choice of treatment. We report an additional case of a 4-year-old girl with a breast tumor diagnosed as a secretory carcinoma without involvement of the axillary lymph nodes. The therapy consisted of simple mastectomy and low axillary dissection. She presented with a local recurrence near the surgical scar 8 months later, and a wide elliptical excision of the scar and underlying tissue was performed with subsequent radiotherapy of the surgical bed. This tumor has a relatively benign behavior and rarely metastasizes. A literature review revealed only 22 cases of breast carcinoma in childhood and adolescence. ▪     

Spinal organization and steroid sensitivity of motoneurons innervating the pubococcygeus muscle in the male rat.

Male rat motoneurons innervating the pubococcygeus muscle were located in the ventral nucleus of lamina IX at the sixth lumbar (L6) and first sacral (S1) spinal cord segments. Retrograde labeling with horseradish peroxidase-wheat germ agglutinin was transported up to second-order dendrites and revealed that these motoneurons have a "U-shaped arborization" of dendrites toward the intermediolateral and intermediomedial nuclei area of lamina VII. This dendritic organization makes a wide "final common path" that probably integrates afferent information from several sources, accounting for the participation of the pubococcygeus muscle in autonomic and somatic processes, such as those related to micturition and reproduction. Castration produced a decrement in the morphometry of these motoneurons. A main effect was a decrement in dendritic length. Steroid replacement indicated that testosterone and estradiol, but not dihydrotestosterone, are able to induce a recovery of morphometric alterations. However, estrogen induced recovery after 2 weeks of treatment, whereas testosterone took 4 weeks. Thus, it is proposed that supraspinal aromatization of testosterone in the male central nervous system might be an important process for the appropriate organization of the pubococcygeus muscle motoneurons and that estradiol seems to need a shorter time of action than testosterone because of differential up-regulation and down-regulation of steroid receptors.     

Medial prefrontal transection enhances social interaction. II: neurochemical studies

Medial prefrontal cortex (MPFC) transection enhances social interaction in an open arena test. Social interaction enhances dopaminergic activity in the nucleus accumbens (NAC). In the present set of experiments, microdialysis probes were implanted in the NAC, and glutamate, gamma-aminobutyric acid (GABA) and dopamine (DA) were measured during electrical stimulation of the MPFC, after coronal transection caudal to the MPFC and after a systemic injection of amphetamine in transected rats. Electrical stimulation of the MPFC caused a transient enhancement of glutamate release in the NAC, no change in GABA levels and a long lasting increase in DA levels. Medial prefrontal transection did not change basal glutamate or GABA levels in the NAC, but increased basal DA levels. Amphetamine administration decreased GABA levels in medial prefrontal transected rats, had no effect on glutamate and increased DA levels more than in controls. The experiments suggest that glutamatergic activity in the accumbens decreases dopamine release. Medial prefrontal transection reduces glutamatergic tone and enhances dopamine release, which probably decreases GABAergic activity in the NAC. Presumably, GABA inhibition in the NAC enhances social interaction.     

Distribution of protein kinase Mzeta and the complete protein kinase C isoform family in rat brain

Protein kinase C (PKC) is a multigene family of at least ten isoforms, nine of which are expressed in brain (alpha, betaI, betaII, gamma, delta, straightepsilon, eta, zeta, iota/lambda). Our previous studies have shown that many of these PKCs participate in synaptic plasticity in the CA1 region of the hippocampus. Multiple isoforms are transiently activated in the induction phase of long-term potentiation (LTP). In contrast, a single species, zeta, is persistently activated during the maintenance phase of LTP through the formation of an independent, constitutively active catalytic domain, protein kinase Mzeta (PKMzeta). In this study, we used immunoblot and immunocytochemical techniques with isoform-specific antisera to examine the distribution of the complete family of PKC isozymes and PKMzeta in rat brain. Each form of PKC showed a widespread distribution in the brain with a distinct regional pattern of high and low levels of expression. PKMzeta, the predominant form of PKM in brain, had high levels in hippocampus, frontal and occipital cortex, striatum, and hypothalamus. In the hippocampus, each isoform was expressed in a characteristic pattern, with zeta prominent in the CA1 stratum radiatum. These results suggest that the compartmentalization of PKC isoforms in neurons may contribute to their function, with the location of PKMzeta prominent in areas notable for long-term synaptic plasticity.     

Extracellular matrix of the human lamina cribrosa

We used immunoperoxidase staining and double immunofluorescent staining to demonstrate the macromolecular components of the extracellular matrix of the lamina cribrosa from young human donors. The cribriform plates were made up of a core of elastin fibers with a sparse, patchy distribution of collagen type III. The plates were coated with collagen type IV and laminin; these basement membrane components were presumably made by the astrocytes that were distributed on the surfaces of the plates. The insertion of the lamina cribrosa in the sclera was made up of concentric, circumferential elastin fibers that surrounded the lamina cribrosa and were continuous with the elastin in the cribriform plates. Astrocytic processes extended into the bundles of elastin fibers, whereas the basement membrane components extended into the sclera. The mechanical properties of the macromolecules of the extracellular matrix of the lamina cribrosa may make this tissue compliant and sensitive to intraocular pressure. Perhaps individual differences in the macromolecular components of this tissue contribute to the glaucomatous changes in the optic nerve head.