Collagen induced platelet aggregation: Requirement for tropocollagen multimers

Fibrillar collagen suspensions and neutral salt soluble collagen were investigated with regard to their platelet aggregating activity. The activity of fibrillar suspensions was highly dependent on the method of preparation and was observed to increase with the fineness of dispersion.

Monodisperse tropocollagen was found not to aggregate platelets. However, aggregating activity developed after multimerizing the molecules by incubation at 37° C. At this stage no fibrils could be detected by measuring the opacity at 400 nm. It is proposed that the triple helix is an insufficient structure for promoting platelet aggregation; multimers of tropocollagen are required to induce this platelet reaction. Evidence for a close correlation between fibril precipitation and development of aggregating activity is presented.

Treatment of soluble collagen with galactose oxidase was shown to interfere with multimerization and consequently to lead to a delayed development of aggregating activity. Enzyme treated and control collagen showed similar aggregating activities after multimerization at 37° C. Treatment of fibrillar collagen with galactose oxidase produced no loss in aggregating activity as compared to control collagen.     

Intraoperative ultrasound examination of the brain

In a preliminary demonstration of cranial intraoperative real-time ultrasound, both supratentorial and posterior fossa scans displayed the pertinent anatomy. A grade III astrocytoma was visualized on the supratentorial scan as well. Ultrasound may be valuable for surgical planning and biopsy procedures because of its reliable depiction of intracranial anatomy and ease of use.     

Q-angle, Pelvic width, and Intercondylar notch width as predictors of knee injuries in women soccer players in South Africa

Objective

To investigate the association between the three anatomical factors of Q-angle (QA), pelvic width (PW) and Intercondylar notch width (INW) and knee injuries among the U-23 female soccer players of South Africa

Methods

The study is a case-control prospective study design. Twenty four U-23 women soccer players of the South African team were purposively chosen to participate in this study. Participants were divided into two groups: group1 (Case) was those with knee injuries, while those without injuries were in group-2 (Control). PW and INW were measured after X-rays of the hip were taken while the QA was measured manually with the goniomenter. Association between anatomical factors and knee injuries were tested with ANOVA.

Results

Q-angle ranged from 14° to 18° for both injured and non injured groups. PW was between 24 –29 cm for both injured and non injured groups. INW was between 1.3mm and 2.8mm for the right and between 1.4mm and 2.5mm for the left notch for the injured group, while INW for the right and left of the non injured group were between 1.7mm to 2.1mm and 1.8mm to 2.1mm, respectively No significant association between knee injuries and each of the anatomical factors was found QA (p= 0.74), PW (p=0.34), INW (right and left respectively) (p=0.142 & p=0.089).

Conclusion

The three anatomical factors of QA, PW and INW could not be used to predict knee injuries amongst the U-23 female players in South Africa.     

Repetitive conundrums of centromere structure and function

In the last few years, a paradox has emerged regarding the relationship of centromere structure and its function. Most centromeric DNAs analyzed to date are composed of a remarkably complex array of repeat structures. In contrast, recent analyses of neocentromeric DNA reveal that repetitive DNA is not a prerequisite for centromere activity. The ubiquity of repetitive sequences among diverse species at sites of primary constriction argues that there is a strong evolutionary link between centromere structure and function. Dynamic mutational processes resulting in amplification, deletion and transposition of repetitive sequences appear to occur frequently in such regions, resulting in considerable interspecific diversity in structure and sequence. One possible solution to this conundrum may be that the rapid accumulation of repetitive sequences within centromeric and pericentromeric DNA is a consequence of functionally active centromeres. Emerging repetitive structures at centromeric sites may be an important byproduct of a functional centromere which ensures that site as an evolutionarily favored position in subsequent meiotic and mitotic lineages. The recent identification of large gene duplications in the vicinity of centromeres may be another example of the enhanced mutational lability of such regions of the genome.      

Socio—cultural factors influencing insecticide treated bed net utilization in a malaria endemic city in north—central Nigeria

ObjectiveTo ascertain the socio-cultural factors influencing the rate of utilization of insecticide treated bed nets (ITNs) in a malaria endemic city of Makurdi, north central Nigeria.MethodsThe study was cross-sectional in nature using systematic sampling method to identify households. Both quantitative and qualitative data was generated from adult women using structured and semi structured questionnaires, and focused group discussions (FGDs) to obtain information on rate and patterns of utilization of ITNs. Information such as age, educational level, marital status, awareness or otherwise of the existence of malaria, and factors influencing rate of ownership and utilization of ITNs were obtained. FGDs were used to obtain qualitative information on rate of utilization of ITNs not captured in the questionnaires. Data obtained was analysed using Epi Info 6 statistical software.ResultsAmong the respondents interviewed, 97.0% (2 013/2 075) were aware of existence of malaria and 87.0% of these (1 751/2 013) would associate it with mosquitoes. The rate of ownership of any bed net, ITNs and untreated bed nets (UTNs) was 25.1%, 17.0% and 8.3%, respectively. Utilization of ITNs among children was 30.0% (112/373) and UTNs 12.9% (48/373). Positive contributors to ITNs utilization were literacy, enhanced economy, experience of marriage, and being gainfully employed (P<0.05); while negative contributors were ignorance, poverty and some cultural beliefs and values.ConclusionsA more synchronized advocacy should be carried out on the potential benefits of ITNs utilization and sustained. Also ITNs should be made available to the people of the community at minimal or no cost.     

A study of anemia in women with asymptomatic malaria parasitaemia at their first antenatal care visit at the General Hospital,Ikot Ekpene,Akwa Ibom State,Nigeria

ObjectiveTo assess the prevalence of anemia and asymptomatia malaria parasitemia and the effect of prior antimalarials therapy on the parasite density in pregnant women at their first antenatal visit at the secondary level health care facility in Nigeria.MethodsThis cross sectional observational study was carried out in the antenatal clinic of General Hospital, Ikot Ekpene, Akwa Ibom State, Nigeria for 3 months period (1^st June to 31^st August, 2009). Five hundred and fourteen women attending their first antenatal registration visits in the hospital were recruited in the study. Socio-demographic information was obtained using pre-tested questionnaires. The malaria parasite was obtained by examining thick and thin blood films prepared on 2 glass slides while the hematocrit was obtained through 2 capillary tubes read by a Hawksleys microhematocrit reader.ResultsA total of 514 pregnant women participated in the study with a mean maternal age of 21.4 years and a mean gestational age at booking of 18.3 weeks. The primigravid women booked at significantly lower gestational age than multigravidae (16.2 weeks vs 21.6 weeks). Most of the women (59.3%) were anemic, out of which 60.4% were primigravida. More than half of the women had moderate to high parasite density and only 6.8% had no malaria parasitemia. All patients with severe anemia were parasitemic. Out of the 479 (93.2%) women with parasitemia, a third had taken antimalarial drugs. A majority (60.3%) of those without prior antimalarial drugs had moderate to high density parasitemia.ConclusionsThis study shows high prevalence of anemia in women with asymptomatic malarial parasitemia, particularly the primigravida. The severity of anemia is directly related to the density of malaria parasitemia. Those with effective antimalarial therapy appear to have low density parasitemia and therefore mild anemia. Routine screening for anemia and malaria parasites at booking, prompt parasite clearance and correction of anemia would reduce the associated maternal and perinatal complications.     

Objective and subjective evaluation of adaptive speech enhancement methods for functional MRI

Purpose:

To recover speech corrupted by functional magnetic resonance imaging (fMRI) acoustic noise using two‐channel adaptive speech enhancement techniques.

Materials and Methods:

Speech corrupted by noise generated from a 3 T MRI scanner was recorded using diffuse‐field microphones and a data acquisition board. Multiband and subband adaptive speech enhancement methods are used to recover the speech signal from the recordings. Normalized least mean squares (NLMS) algorithm was used for updating the filter coefficients in each band.

Results:

The methods are successful in enhancing the speech quality. They are successful in improving the convergence rate of the adaptive filter. Multiband and subband methods have a similar performance in terms of noise reduction and in the subjective tests. The subband method introduces less speech distortion compared to the multiband method. The subband method requires a lower number of computations per sample.

Conclusion:

Adaptive speech enhancement techniques are effective in reducing fMRI background noise in the recordings. Based on the analysis, we conclude that subband‐based methods are more suited for enhancing speech corrupted by fMRI noise. J. Magn. Reson. Imaging 2010;31:46–55. © 2009 Wiley‐Liss, Inc.