Solid waste management in Abuja, Nigeria

The new city of Abuja provided an opportunity to avoid some of the environmental problems associated with other major cities in Africa. The current status of solid waste management in Abuja has been reviewed and recommendations for improvements are made. The existing solid waste management system is affected by unfavourable economic, institutional, legislative, technical and operational constraints. A reliable waste collection service is needed and waste collection vehicles need to be appropriate to local conditions. More vehicles are required to cope with increasing waste generation. Wastes need to be sorted at source as much as possible, to reduce the amount requiring disposal. Co-operation among communities, the informal sector, the formal waste collectors and the authorities is necessary if recycling rates are to increase. Markets for recycled materials need to be encouraged. Despite recent improvements in the operation of the existing dumpsite, a properly sited engineered landfill should be constructed with operation contracted to the private sector. Wastes dumped along roads, underneath bridges, in culverts and in drainage channels need to be cleared. Small-scale waste composting plants could promote employment, income generation and poverty alleviation. Enforcement of waste management legislation and a proper policy and planning framework for waste management are required. Unauthorized use of land must be controlled by enforcing relevant clauses in development guidelines. Accurate population data is necessary so that waste management systems and infrastructure can be properly planned. Funding and affordability remain major constraints and challenges.

Computer analysis of upper gastrointestinal endoscope images

Gastro-oesophageal reflux disease (GORD) occurs in up to 40% of adults in the West. Oesophagitis is a major determinant in the treatment of GORD but its current classification systems are subjective. In order to help to provide objective interpretation of upper gastro-intestinal (GI) endoscope examination and reduce inter-observer variability, we developed a computer image analysis system. Digital video recordings were made on patients with clinical evidence of reflux oesophagitis. Cross-sectional profiles of hue and saturation data were analysed on images from seven patients with grade B or C oesophagitis (LA grading). This analysis showed clear changes in hue (p = 0.01) and saturation (p = 0.001). These results suggest that quantification of upper GI endoscopic images is feasible and may help in objective assessment.

Sildenafil citrate significantly improves nocturnal penile erections in sildenafil non-responding patients with psychogenic erectile dysfunction

Effects of sildenafil citrate on nocturnal penile tumescence and rigidity (NPTR) were evaluated among sildenafil non-responding patients with psychogenic erectile dysfunction. All patients (n=30), equally divided into groups I and II, completed four consecutive nights using the RigiScan Plus device. Sildenafil citrate (50 mg) was given in the third night in group I and in the fourth in group II, whereas a placebo was given in the remaining nights. Additional patients (n=12) receiving only a placebo served as a control group. Results of NPTR recordings revealed neither significant differences between the control and non-sildenafil nights of both test groups, nor between the corresponding values of both groups (P>0.05). On the other hand, when sildenafil citrate nights of groups I and II taken together were compared with placebo nights, a significant increase of total events duration (P<0.001), average rigidity of the tip (P<0.05) and base (P<0.01), and rigidity activity unit (RAU) and tumescence activity unit (TAU) of tip and base (P<0.001) was observed. These results suggest that performance anxiety may be responsible for failure of response during awakening.

Mechanisms of estrogen receptor action in the myocardium. Rapid gene activation via the ERK1/2 pathway and serum response elements

We have previously shown that the myocardium is a target tissue for estrogen. Here, we have identified rapid non-nuclear estrogen effects on the expression of the early growth response gene-1 (Egr-1) in cardiomyocytes. Egr-1 mRNA and protein were rapidly and strongly induced by estrogen in an estrogen receptor-dependent manner via the extracellular signal-regulated kinase, ERK1/2. A promoter analysis study of a 1.2-kilobase Egr-1 promoter fragment revealed that the serum response elements (SREs) but not the estrogen response elements or AP-1 sites are responsible for Egr-1 induction by estrogen, identifying a novel mechanism of estrogen receptor-dependent gene activation in the myocardium. Both estrogen receptor-alpha and -beta induced the Egr-1 promoter via the SREs as well as an artificial promoter consisting of only five SREs in cardiomyocytes. Electrophoretic mobility shift assays showed that a protein complex containing serum response factor or an antigenically related protein was recruited to the SREs by estrogen treatment of primary cardiomyocytes. The recruitment of the protein complex was inhibited by the specific estrogen receptor antagonist ICI 182,780 as well as the MEK inhibitor PD 98059. Taken together, these results identify SREs as important promoter control elements for an estrogen receptor-dependent mechanism of gene activation in the myocardium.

Retinoids as ligands and coactivators of protein kinase C alpha

Whereas retinoic acids control nuclear events, a second class of retinol metabolites, that is, the hydroxylated forms exemplified by 14-hydroxy-retro-retinol (HRR), operate primarily in the cytoplasm. They function as regulatory cofactors for cell survival/cell death decisions. In accordance with these biological aspects, we demonstrate that these retinoids bound protein kinase C (PKC) alpha with nanomolar affinity and markedly enhance the activation of PKC alpha and the entire downstream MAP kinase pathway by reactive oxygen species. HRR was 10 times more efficient than retinol, and the optimum doses are 10-7 and 10-6 M, respectively. PKC alpha activation was reversed rapidly by imposition of reducing conditions. The retinoid binding site was mapped to the first cysteine-rich region in the regulatory domain, C1A, yet was distinct from the binding sites of diacylglycerol and phorbol esters. The C1B domain bound retinoids poorly. The emerging theme is that retinoids serve as redox regulators of protein kinase C.

The cysteine-rich regions of the regulatory domains of Raf and protein kinase C as retinoid receptors

Vitamin A and its biologically active derivatives, the retinoids, are recognized as key regulators of vertebrate development, cell growth, and differentiation. Although nuclear receptors have held the attention since their discovery a decade ago, we report here on serine/threonine kinases as a new class of retinoid receptors. The conserved cysteine-rich domain of the NH(2)-terminal regulatory domains of cRaf-1, as well as several select domains of the mammalian protein kinase C (PKC) isoforms alpha, delta, zeta, and mu, the Drosophila and yeast PKCs, were found to bind retinol with nanomolar affinity. The biological significance was revealed in the alternate redox activation pathway of these kinases. Retinol served as a cofactor to augment the activation of both cRaf and PKC alpha by reactive oxygen, whereas the classical receptor-mediated pathway was unaffected by the presence or absence of retinol. We propose that bound retinol, owing to its electron transfer capacity, functions as a tag to enable the efficient and directed redox activation of the cRaf and PKC families of kinases.

Percutaneous mechanical mitral commissurotomy with a newly designed metallic valvulotome: immediate results of the initial experience in 153 patients

BACKGROUND

Percutaneous balloon valvotomy has become a common treatment of mitral stenosis, but the cost of the procedure remains a limitation in countries with restricted financial resources, leading to a frequent reuse of the disposable catheters. To overcome this limitation, a reusable metallic valvotomy device has been developed with the goals of both improving the mitral valvotomy results and decreasing the cost of the procedure.

METHODS AND RESULTS

The device consists of a detachable metallic cylinder with 2 articulated bars screwed onto the distal end of a disposable catheter whose proximal end is connected to an activating pliers. By the transseptal route, the device is advanced across the valve over a traction guidewire. Squeezing the pliers opens the bars up to a maximum extent of 40 mm. The clinical experience consisted of 153 patients with a broad spectrum of mitral valve deformities. The procedure was successful in 92% of cases and resulted in a significant increase in mitral valve area, from 0.95+/-0.2 to 2. 16+/-0.4 cm2. No increase in mitral regurgitation was noted in 80% of cases. Bilateral splitting of the commissures was observed in 87%. Complications were 2 cases of severe mitral regurgitation (1 requiring surgery), 1 pericardial tamponade, and 1 transient cerebrovascular embolic event. In this series, the maximum number of consecutive patients treated with the same device was 35.

CONCLUSIONS

The results obtained with this new device are encouraging and at least comparable to those of current balloon techniques. Multiple uses after sterilization should markedly decrease the procedural cost, a major advantage in countries with limited resources and high incidence of mitral stenosis.

Palliative balloon valvoplasty of the pulmonary valve in tetralogy of Fallot

Balloon dilation of the pulmonary valve was performed in 54 patients with tetralogy of Fallot with severe cyanosis, high haematocrit and severe valvar pulmonary stenosis. Clinical, echocardiographic, angiographic, and haemodynamic data were analyzed before and after the procedure. After balloon dilation, the systemic oxygen saturation increased from a mean value of 66% to 85%. The mean value of the haematocrit before dilation was 55 + 13, and decreased to 47 after dilation (p < 0.002) in 2 months follow-up. Balloon dilation increased the size of the pulmonary valvar orifice from a mean value of 9 + 5 mm to 11.5 + 2 mm (p < 0.005). The mean Z score of the pulmonary valves, which was -3 + 1.3 before dilation, increased to -1.1 + 1.1 immediately after the procedure (p < 0.05). The size of the right and left pulmonary arteries increased after dilation from 9 mm to 10 mm, and from 8.7 + 2.4 mm to 9.8 + 2.3 mm, respectively (p < 0.05). The comparable mean Z scores increased from -2.8 + 1.9 SD to -1.8 + 1.4 SD, and from -2.4 + 1.9 SD to -1.5 + 1.6 SD for the right and left branches, respectively (p < 0.05). In patients with stenosis at the bifurcation of the pulmonary trunk and hypoplasia of the left artery, successful dilation of the pulmonary valve lead to an increase of flow and improvement in size of the hypoplastic segment. In conclusion, initial balloon dilation of the pulmonary valve in tetralogy of Fallot resulted in increase of the Z score for the pulmonary valve and improved antegrade pulmonary blood flow, inducing growth of the pulmonary arteries and ameliorating the anatomic and physiologic preoperative condition.

Radiation-induced red cell damage: role of reactive oxygen species

BACKGROUND

Cellular blood components are irradiated to prevent graft-versus-host disease in transfusion recipients at risk for this syndrome. Because gamma radiation can result in the production of reactive oxygen species, the role of reactive oxygen species was investigated in radiation-induced red cell damage.

STUDY DESIGN AND METHODS

Whole blood from normal donors was exposed to various doses of t-butyl hydroperoxide (0-1 mM) and/or to gamma-radiation (0-50 Gy). Oxidative damage was assessed by the extent of lipid peroxidation (measured by thiobarbituric acid-reactive substances [TBARS]) and hemoglobin oxidation. Fresh blood was divided into three parts-one initially irradiated and stored, another stored with portions irradiated weekly, and a third stored without irradiation. TBARS and hemoglobin oxidation were measured weekly.

RESULTS

As expected, t-butyl hydroperoxide induced TBARS formation and hemoglobin oxidation in a dose-dependent fashion. The gamma-radiation not only increased hemoglobin oxidation and TBARS formation, but also enhanced the t-butyl hydroperoxide effect on red cells. Red cell storage increased TBARS generation and hemoglobin oxidation in a time-dependent fashion. When radiation was administered either initially or after weekly storage, TBARS production and hemoglobin oxidation were increased over that measured in unirradiated paired controls.

CONCLUSION

Gamma radiation at clinically used doses increases lipid peroxidation and hemoglobin oxidation in human red cells. The effect of gamma-radiation is accentuated by blood storage and induces damage independent of time of storage.

Role of the duplicated CCAAT box region in gamma-globin gene regulation and hereditary persistence of fetal haemoglobin

Hereditary persistence of fetal haemoglobin (HPFH) is a clinically important condition in which a change in the developmental specificity of the gamma-globin genes results in varying levels of expression of fetal haemoglobin in the adult. The condition is benign and can significantly alleviate the symptoms of thalassaemia or sickle cell anaemia when co-inherited with these disorders. We have examined structure-function relationships in the -117 HPFH gamma promoter by analysing the effect of mutating specific promoter elements on the functioning of the wild-type and HPFH promoters. We find that CCAAT box mutants dramatically affect expression from the HPFH promoter in adult blood but have little effect on embryonic/fetal expression from the wild-type promoter. Our results suggest that there are substantial differences in the structure of the wild-type gamma promoter expressed early in development and the adult HPFH promoter. Together with previous results, this suggests that gamma silencing is a complex multifactorial phenomenon rather than being the result of a simple repressor binding to the promoter. We present a model for gamma-globin gene silencing that has significant implications for attempts to reactivate the gamma promoters in human adults by pharmacological means.

TBP binding and the rate of transcription initiation from the human beta-globin gene

DNA-protein interaction studies in vitro revealed several factors binding over the TATA box and the region of transcription initiation (cap) site of the human beta-globin promoter; TATA binding protein TBP at -30, Sp1 at -19, GATA-1 at -12 and +5, YY1 at -9 and a novel factor C1 over the site of initiation (-4 to +7). Point mutants which specifically abolish the binding of each of these proteins were tested in a beta-globin locus control region (LCR) construct which allows quantitative comparisons at physiological levels of transcription. Only mutants which drastically affect the binding of TBP resulted in decreased levels of transcription. A threshold value of TBP binding of 15-30% of wild type was sufficient to give normal levels of transcription. This indicates that the association of TF IID with the TATA box is not limiting in the rate of initiation of transcription.

Antigen retrieval using pH 3.5 glycine-HCl buffer or urea solution for immunohistochemical localization of Ki-67

A new antibody (MIB-1) has been described, permitting the demonstration of Ki-67 proliferation antigen in paraffin sections. However, satisfactory results were obtained only after subjecting tissue sections to microwave based antigen retrieval in citrate buffer solution. Other buffer solutions produce equivalent or better results and also permit use of the original Ki-67 antibody, which hitherto has been considered ineffective for paraffin sections.

Malignant progression of SV40-immortalised human milk epithelial cells

A human breast epithelial cell line (Hu-MI), established by microinjecting SV40 DNA into human milk epithelial cells, exhibits the phenotype of luminal epithelial cells and is neither clonogenic nor tumorigenic. From this cell line we have selected two sublines, HuMI-T and HuMI-TTul, reflecting different stages of spontaneous transformation. HuMI-T cells grow anchorage-independently, but do not induce tumours in nude mice. HuMI-TTul cells are clonogenic as well as tumorigenic. Cells from both lines exhibit polymorphic structural and numerical chromosome aberrations. Immortalisation of normal luminal epithelial cells from human mammary gland with SV40 DNA alone may thus cause random genetic changes eventually resulting in tumorigenic cell lines. Since Hu-MI, HuMI-T and HuMI-TTul represent some of the consecutive stages taking place during cellular transformation, they are particularly suited as a novel in vitro model system to study progression of human breast cancer.

The regulation of human globin gene switching

This paper describes the mechanism of regulation of the human beta-globin on the basis of a number of natural mutations and experiments in transgenic mice. From these data we conclude that this multigene locus is regulated at a number of different levels involving specific interactions between the Locus Control Region (LCR) and the individual genes. Most important is the action of stage specific transcription factors acting on sequences immediately flanking the genes. In addition, specificity is obtained through specific interaction of the genes with the LCR and through competition of the genes for interaction with the LCR.

Acute effects of cocaine on spontaneous and discriminative motor functions: relation to route of administration and pharmacokinetics

Rats administered cocaine i.p. and p.o. (7.5-30 mg/kg) showed dose-related increases in locomotor (LM) and small-movement activities, with LM rates decreasing over the 2-hr session, except at the largest i.p. dose, for which rates were greater in the 2nd hr. Lidocaine p.o. (15-30 mg/kg) did not increase activity. Relating the area under the curve measures for serum cocaine (concentration-time) and LM activity (LM activity-time) for 2 hr postadministration indicated that cocaine was about twice as potent i.p., compared to p.o., in increasing LM activity. Cocaine (i.p. and p.o.) produced dose-related decrements in both discriminative motor control performance and in task work rate, whereas lidocaine p.o. did not. The motor control decrements produced by cocaine were approximately comparable by i.p. and p.o. routes, whereas effects on LM rates were much greater by i.p. than by p.o. administration. The effects of cocaine by both routes on LM rates were proportionally much greater than its effect on motor control performance. Changes in LM rates and motor control performance over the postadministration period were related to the pharmacokinetic features (maximum serum concentration, time to maximum serum concentration and elimination half-life) of cocaine observed for the routes explored (i.p., p.o. and s.c.). Tail-tip serum samples, although yielding conservative estimates of cocaine concentration, correlated well with trunk serum and brain cocaine levels.

Anti-BLA.36 monoclonal antibody shows reactivity with Hodgkin's cells and B lymphocytes in frozen and paraffin-embedded tissues

A newly developed monoclonal antibody, anti-BLA.36, raised against a Hodgkin cell line, was shown to have reactivity with Reed-Sternberg cells and activated B lymphocytes and appears to be distinct from other antibodies which identify antigens of hematopoietic cells. Anti-BLA.36 was evaluated in B5-fixed paraffin-embedded tissue from 16 cases of Hodgkin's disease of various types and 35 cases of non-Hodgkin's lymphomas representative of the different major subtypes. The specificity of anti-BLA.36 was compared with other antibodies that have been used to mark Hodgkin's cells and B lymphocytes: namely, L26, LN-1, Leu-M1 and Ber-H2, as well as UCHL-1, a pan-T lymphocyte marker. In addition, a subset of the cases was evaluated using frozen tissue in order to validate the staining characteristics of anti-BLA.36 as observed in fixed paraffin sections. Anti-BLA.36 was found to react with Hodgkin's cells more consistently than the other antibodies used in this panel. The antibody reacted with an antigen on Reed-Sternberg cells and their variants (Hodgkin's cells) in all four subtypes of Hodgkin's disease, and with a subset of reactive and malignant B lymphocytes, but not with T lymphocytes. It may, therefore, be useful in the evaluation of non-Hodgkin's lymphomas. Finally, this is the first antibody raised to a Hodgkin's cell line which also consistently marks reactive and malignant B cells, but not T cells. The implications of this observation are discussed in relation to the cellular origin of the Reed-Sternberg cell and the overall nature of Hodgkin's disease.

BLA.36: a glycoprotein specifically expressed on the surface of Hodgkin's and B cells

Anti-BLA.36 is an antibody that recognizes a glycoprotein with an apparent molecular weight of 36 kilodaltons, termed B lymphocyte antigen (BLA.36). By using an immunochemical staining technique, BLA.36 was found to be specifically expressed on Hodgkin's and human B cell lines including early B progenitor cells. Other cell lines representing T cell lymphomas, non-B large cell lymphomas, melanomas and carcinomas were consistently negative. BLA.36 is distinct from the previously identified antigens of hematopoietic cell lineage. The specificity of expression of BLA.36 in tissue sections mirrored that of cell lines. In normal tissues, BLA.36 was detectable predominantly on cells in the germinal center and mantle zone of reactive follicles in lymph nodes and spleens. In hematopoietic malignancy, the antigen was expressed on the surface of Reed-Sternberg cells, mononuclear Hodgkin's cells and also on malignant cells of B cell lineage. BLA.36 was also observed on lymphoid cells of 10 to 24 week fetal liver: a double-antibody-staining method revealed that these BLA.36-positive cells also contained immunoglobulin mu heavy chain consistent with identification as early B cells. Under these conditions, T lymphocytes, histiocytes, granulocytes, macrophages, stromal cells in lymphoid tissue, and both normal and neoplastic epithelial cells were consistently negative for the expression of the antigen, with the single exception of a variable proportion of Kupffer cells in normal liver. The antibody has already established its usefulness for the identification of Reed-Sternberg and Hodgkin's cells, and also normal and malignant B lymphocytes in frozen as well as formalin-fixed tissue sections. Furthermore, binding of F(ab)2 fragments of anti-BLA.36 to antigen-positive cell lines specifically inhibited the proliferation of cells. Such an effect was eliminated by the removal of the antibody from the culture-medium, suggesting a possible growth-related function of the antigen in Hodgkin's and B cells.

Generation and characterization of a murine monoclonal antibody to cervical glandular epithelium using mice rendered tolerant to cervical squamous epithelium

Murine monoclonal antibodies that distinguish glandular from squamous epithelia in human tissue were generated using a procedure that involved tolerization prior to immunization. Tolerization was achieved by injection of newborn (24 hrs old) Balb/c mice with extract of normal cervical tissue containing squamous epithelium (the tolerogen). Three weeks later, mice showing no evidence of antibodies to tolerogen in their sera were immunized with an extract of cervical tissue containing both glandular and squamous epithelia. Following immunization, the sera from mice subjected to this treatment showed strong reactivity with glandular cells but not with squamous cells in sections of frozen tissue examined by an indirect immunohistological method. Spleen cells from mice showing this pattern of serum reactivity were used as fusion partners with a mouse myeloma cell line in order to generate monoclonal antibodies. Following extensive screening, one monoclonal antibody (designated anti-GEA.49) was selected for further study on the basis of reactivity with high affinity to glandular epithelium and a complete absence of staining of squamous and connective-tissue cells. Detailed tests of specificity and patterns of reactivity indicate that the antigen detected by the antibody is expressed on the apical plasma membrane of glandular epithelia and is a glycoprotein with an apparent molecular weight of 49 kilodaltons. Both immunohistological and biochemical methods demonstrated the expression of the antigen on glandular epithelia but not on squamous epithelia from several sources, underlining the usefulness of tolerization/immunization approach for generating antibodies with particular specificity requirements.