Interpreting DNA mixtures

Apolipoprotein A-I (apo A-I) and apolipoprotein A-II (apo A-II) represent 80 90% of the protein content of high density lipoproteins (HDL). Previously we have identified a Finnish family with an apo A-I variant (Lys107-->0) associated with reduced plasma HDL cholesterol level and decreased lipoprotein (Lp)(AI w AII) concentration compared to unaffected family members. To determine the in vivo metabolism of apo A-I and apo A-II in the carriers of apo A-I (Lys107-->0) variant we radioiodinated normal apo A-I with 125I and apo A-II with 131I and compared the kinetic data of two heterozygous apo A-I(Lysl07-->0) patients (HDL cholesterol leves 0.31 and 0.69 mmol/l) to that of eight normolipidemic, healthy control subjects. Plasma radioactivity curves of 125I-labelled normal apo A-I of the patients demonstrated accelerated clearance of apo A-I compared to control subjects. In the two patients the fractional catabolic rates (FCR) of apo A-I were 0.347/day and 0.213/day, respectively, while the mean FCR of apo A-I of the control subjects was 0.151 +/- 0.041/day. Similarly, the plasma decay curves of the 131I-labelled apo A-II showed more rapid clearance of apo A-II in the two patients than in control subjects. The FCR of apo A-II in the two patients were 0.470/day and 0.234/day, while the mean FCR of apo A-II in control subjects was 0.154 +/- 0.029/day. The calculated production rates of apo A-I were similar in patients and in control subjects, and the production rates of apo A-II were significantly higher in patients than in control subjects. Our results show that the Lp(AI w AII) deficiency in patients with the apo A-I(Lys107-->0) is associated with increased fractional catabolic rates of normal apo A-I and apo A-II, while the production rates of these apolipoproteins are normal (apo A-I) or slightly increased (apo A-II).     

Granulocyte colony-stimulating factor (G-CSF) dose-dependent efficacy in peripheral blood stem cell mobilization in patients who had failed initial mobilization with chemotherapy and G-CSF

For 10 consecutive patients in our unit who did not show a significant rise in blood progenitor cells within 14 days following chemotherapy and G-CSF, we increased the G-CSF dose from 5 to 10 microg/kg/day (n = 9) or from 10 to 15 microg/kg/day (n = 1). As a result, there were significant increases in total yield as well as yield per apheresis of mononuclear cells, CD34+ cells and CFU-GM (P < 0.025, <0.01 and <0.005, respectively). After G-CSF dose escalation, six of the 10 patients had sufficient CD34+ cells for performing transplantation. These results demonstrate a dose-dependent response of progenitor cell mobilization by G-CSF when used in combination with chemotherapy. Moreover, increasing the dose of G-CSF as late as the third week of mobilization may still provide sufficient cell yield even with patients who did not show a significant mobilization with conventional doses of G-CSF.     

Meniscal regeneration in the long-term after total meniscectomy?

A cohort of 39 patients (28 male, 11 female) that had undergone total meniscectomy as adolescents (mean age 16 years) underwent FISP 3D Magnetic Resonance Imaging at a mean follow up of 30 years. The presence of meniscal tissue was assessed by two independent observers blinded to the operation details. The volume of any meniscal tissue present was calculated. A posterior horn remnant was seen in 57% of medial and 45% of lateral meniscectomy cases. The mean volume of an operated medial meniscal remnant was 0.29 mL compared with a mean volume of 1.15 mL for an intact medial meniscus. The mean volume of an operated lateral meniscal remnant was 0.30 mL compared with 1.07 mL for an intact lateral meniscus. We have shown that the incidence of incomplete excision of the posterior horn is more common after total medial meniscectomy, and that at a mean follow up of 30 years there is no convincing in vivo MRI evidence of long-term meniscal regeneration.     

Clinical response of localized recurrent periodontitis treated with scaling, root planing, and tetracycline fiber

The purpose of this study was to compare the clinical efficacy of scaling and root planing alone versus tetracycline fiber therapy used adjunctively with scaling and root planing in the treatment of nonresponsive active periodontitis in patients under supportive periodontal therapy. Thirty patients who were receiving supportive treatment and had at least two nonadjacent periodontitis sites with a probing depth of between 4 and 8 mm and bleeding on probing, or had aspartate aminotransferase (AST) levels above 800 microIU in the gingival crevicular fluid in separate quadrants participated in this study. For each patient, the test sites were treated with scaling and root planing plus tetracycline fibers while the control site was treated with scaling and root planing only. Probing depths, clinical attachment levels, gingival recession, AST levels, and bleeding on probing were recorded and subgingival plaque samples were collected at baseline and 1, 3, and 6 months following treatment. At 3 months after treatment, there was a reduction of bleeding on probing and probing depth, and a gain of clinical attachment in both test and control sites. The mean reduction in probing depth of the test sites was 1.38 mm and the attachment gain was 0.8 mm after 6 months. The clinical response obtained at 3 months following therapy was maintained throughout the 6-month follow-up period. However, there were no statistically significant differences between sites treated with scaling and root planing alone and those treated with combined tetracycline therapy. Most of the reductions of probing depths in the fiber group were attributed to gingival recession. The present study did not confirm the efficacy of adjunctive tetracycline fibers in treating nonresponsive sites in maintenance subjects with regard to probing depth reduction or clinical attachment gain. Reinfection of the pockets from untreated sites and extra-crevicular regions may explain the insignificant response to local tetracycline therapy.     

Racial differences in nitric oxide-mediated vasodilator response to mental stress in the forearm circulation

An abnormal hemodynamic response to stressful stimuli has been proposed as a mechanism involved in the higher prevalence of hypertension in blacks. Given the important role of nitric oxide (NO) in the regulation of cardiovascular homeostasis, we investigated the possibility of racial differences in vascular NO activity during mental stress. To test this hypothesis, we compared the forearm blood flow (FBF) response to mental stress in 14 white and 12 black healthy subjects during intra-arterial infusion of either saline or NO synthesis inhibitor N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min). We also examined vascular responses of the two groups to intra-arterial infusion of sodium nitroprusside (0.8 to 3.2 microg/min), an exogenous NO donor. During saline infusion, the increase in FBF from baseline induced by mental stress was significantly higher in whites than in blacks (109+/-20% versus 58+/-8%; P=0.03). L-NMMA significantly reduced stress-induced increase in FBF in whites (from 109+/-20% to 54+/-11%; P=0.004) but not in blacks (from 58+/-8% to 42+/-10%; P=0.24); thus, the vasodilator effect of stress testing during L-NMMA was similar in whites and blacks (54+/-11% versus 42+/-10%; P=0.44). The vasodilator response to sodium nitroprusside was also lower in blacks than in whites (maximum flow, 6.9+/-2 versus 11.6+/-3.5 mL x min(-1) x dL(-1); P=0.001) and was not significantly modified by L-NMMA in either group. Our findings indicate that blacks have a reduced NO-dependent vasodilator activity during mental stress. This difference seems related to reduced sensitivity of smooth muscle to the vasodilator effect of NO and may play some role in the increased prevalence of hypertension and its complications in blacks.     

The characterization of a subgenomic RNA and in vitro translation products of oat chlorotic stunt virus

Apoptosis has classically been viewed as a process not involving mitochondria, whereas the implication of mitochondrial dysfunction in necrosis has been recognized for several decades. Recently, it has become clear that apoptosis implies a disruption of mitochondrial membrane intregrity that is decisive for the cell death process. Cytofluorometric methods assessing the mitochondrial membrane function and structure can be employed to demonstrate that, at least in most models of apoptosis, mitochondrial changes precede caspase and nuclease activation. Moreover, pharmacological and genetic experiments suggest that the loss of mitochondrial membrane integrity is a critical event of the apoptotic process, beyond or at the point of no return of programmed cell death. Inhibitors of the mitochondrial megachannel (= permeability transition pore) can prevent both the mitochondrial and the post-mitochondrial manifestations of apoptosis.     

Outcome of transfusion of K:11 erythrocytes in a patient with anti-K11 antibody

Arteriovenous (AV) malformations are rare and may occur at various locations, like in the brain, liver, lungs, or in the subcutaneous tissue. This case report describes an AV malformation from the right occipital artery. The value of combined B-mode ultrasonography and color Doppler mode imaging of masses in the neck region is discussed.     

Angiotensin-(1-7) immunoreactivity in the hypothalamus of the (mRen-2d)27 transgenic rat

The distribution of angiotensin-(1-7) immunoreactive neurons was compared to those of vasopressin-(VP) and oxytocin-(OT) immunoreactive (IR) neurons in the hypothalamus of adult (mRen-2d)27 transgenic hypertensive and Sprague-Dawley rats. In both strains, angiotensin (Ang)-(1-7)-IR cells were found in the supraoptic nucleus (SON), and in the anterior (ap-), medial (mp-), and lateral (lp-) parvocellular, and posterior magnocellular (pm-) subdivisions of the paraventricular (PVN) nucleus. Three-dimensional reconstructions showed that cells immunoreactive to Ang-(1-7) and VP were specifically co-distributed in the SON and in the pmPVN. Double-labeling neurons for both peptides revealed that both Ang-(1-7) and VP were colocalized in a subpopulation of neurons in the pmPVN and SON. In combination with previous studies, our results suggest that Ang-(1-7) and VP are colocalized, co-released and may have a combined action at a common target. In addition, the introduction of the mouse submandibular renin (mRen-2d) transgene into Sprague-Dawley rats does not appear to have altered the fundamental organization of hypothalamic peptide systems involved in fluid homeostasis.     

Influence of magnesium substitution on a collagen-apatite biomaterial on the production of a calcifying matrix by human osteoblasts

The induction of a calcifying matrix is of great interest in the restoration of bone defects. In a previous in vitro study we demonstrated that a collagen sponge constituted of type I collagen fibrils, chondroitin sulfates, and hydroxyapatite crystals induces an earlier and a more abundant synthesis of a new extracellular calcifying matrix than do other biomaterials such as collagen or hydroxyapatite alone. Bone mineral contains various amounts of magnesium ions, either adsorbed at the surface of apatite crystals or incorporated inside the crystal structure. Magnesium is known to reduce the degradation rate of tricalcium phosphate ceramics and to influence the crystallization of mineral substance. Thus we evaluated two sponges modified with different substituted apatites. The substituted low magnesium-containing apatite sample decreased the osteoinductive properties of the sponge whereas the substituted high magnesium-containing apatite sample had a toxic effect on bone cells and prevented the formation of any extracellular matrix. Such a toxic effect can be explained by the presence of large numbers of magnesium ions released into the culture medium even though at physiological level magnesium is able to promote bone mineralization and to control the growth of hydroxyapatite crystals. Thus collagen sponges containing hydroxyapatite remain one of the most appropriately evaluated biomaterials used for the restoration of periodontal pockets and bone defects.     

The ratio of initial/residual DNA damage predicts intrinsic radiosensitivity in seven cervix carcinoma cell lines

The single-cell gel electrophoresis (comet) assay was used to measure radiation-produced DNA double-strand breaks (dsbs) in a series of seven cervical tumour cell lines (ME180, HT3, C33A, C41, SiHa, MS751 and CaSki). The proportion of DNA dsbs was measured immediately after radiation treatment (initial damage) and 16 h later after incubation at 37 degrees C (residual damage). Linear dose-response curves were seen for initial (slopes 0.23-0.66) and residual (slopes 0.16-0.87) DNA dsbs. Neither of the slopes of the linear regression analysis on the initial and on the residual DNA dsbs dose-response curves (range 0-80 Gy) correlated with SF2 (surviving fraction at 2 Gy) measured after high- (HDR) or low-dose-rate (LDR) irradiation. An association was evident between SF2 after HDR and LDR irradiation and the ratio of the absolute level of initial and residual damage after a single dose of 60 Gy. However, a significant correlation was found between HDR (r= -0.78, P = 0.04) and LDR (r = -0.86, P = 0.03) SF2 values and the ratio of the slopes of the initial and residual DNA dsbs dose-response curves (range 0.47-0.99), representing the fraction of DNA damage remaining. These results indicate that the neutral comet assay can be used to predict radiosensitivity of cervical tumour cell lines by assessing the ratio of initial and residual DNA dsbs.