Optimal control analysis of a tuberculosis model with exogenous re-infection and incomplete treatment

A new mathematical model of tuberculosis (TB) featuring exogenous re-infection and incomplete treatment is presented and analyzed. The model divides total population into susceptible, latently infected, actively infected (uninformed and enlightened), and treatment classes. The model with or without incomplete treatment exhibits backward bifurcation phenomenon, which is caused by the presence of exogenous re-infection. However, further investigation reveals that the absence of incomplete treatment has the potential to reduce the backward bifurcation range significantly. The global dynamics of the TB model without exogenous re-infection is completely determined by the basic reproduction number under certain modifications on parameters. Furthermore, the model is extended to include three time-dependent control functions, such as public awareness campaign, treatment effort, and preventive control against incomplete treatment. The existence of the optimal control for the nonautonomous model is proven and the three controls are characterized using Pontryagin's maximum principle. Numerical simulations are performed to show the significance of singular implementation of each of the controls and combination of the three controls in minimizing the TB burden in the population.     

Plasma magnesium in adult Nigerian patients with epilepsy

The objective of this study was to determine the relationship between plasma magnesium levels and epilepsy. The study was carried out at the Lagos University Teaching Hospital. Plasma magnesium was estimated using the calmigite dye colorimetric method in 45 adults with epilepsy and 35 healthy controls. Plasma concentrations of calcium, phosphorus and albumin were also estimated. The mean plasma magnesium in the patients was 0.98 mm0l/L (0.05) while that in the controls was 1.15 mmol/L (0.28). The mean plasma magnesium in the epileptics was significantly lower than that obtained in the controls (p < 0.001). Age of onset of seizures, seizure frequency and duration of treatment did not influence the plasma magnesium levels. Low plasma magnesium is associated with epilepsy, further studies may determine the influence of anti-epileptic drug therapy on plasma magnesium levels. Keywords: magnesium, seizures, Nigeria.     

A new technique in the laparoscopic resection of cornual ectopic pregnancies: a case series

Cornual ectopic pregnancies are a challenging dilemma faced in the early pregnancy setting. They are associated with high morbidity and mortality rates when compared to standard tubal ectopic pregnancies mainly due to their late presentation and significant haemorrhage and hysterectomy risk. Laparoscopic resection has been described successfully; however, the procedure can be technically very challenging and can carry significant potential risks of bleeding and conversion to laparotomy. Carboprost is a synthetic prostaglandin analogue, used widely in the management of obstetric haemorrhage, with its main mode of action being myometrial contractions. We present a series of four cases where intramyometrial carboprost injection was used successfully, prior to the laparoscopic resection of cornual ectopic pregnancies, to produce consistent and reproducible surgical benefits including prolonged myometrial contractions and subsequent reduced uterine blood flow. This results in a significant reduction in intraoperative blood loss as well as a clearer demarcation of the ectopic pregnancy and a technically easier resection.     

Dilemmas in management of bilateral ectopic pregnancies—report of two cases and a review of current practice

Simultaneous bilateral ectopic pregnancies occurring spontaneously or following assisted conception techniques, although rare, present the clinician with diagnostic uncertainty and management dilemmas which may have an implication on the patient’s future fertility. A review of available literature suggests that there is no universally accepted management strategy towards this condition, and care needs to be tailored to the needs of the patient, patient’s preferences and the clinical picture. We report two such rare cases of simultaneous bilateral ectopic pregnancies with different management and outcomes highlighting the fact that these cases not only pose diagnostic and management challenges but also has complex ethical issues associated with it.     

The lactate dehydrogenases in malignant and non-malignant diseases

The objective of this paper was to determine different patterns of Lactate Dehydrogenase(LD) isoenzymes in serum, pleural effusions and ascitic fluid collections and their usefulness in the differential diagnosis of malignant and non-malignant diseases. It was a case control study carried out at the Lagos University Teaching Hospital. Forty- six patients with pleural or ascitic fluid collection (male and female, age range between 18 and 65 years) made up of Twenty-two patients with malignant diseases and twenty-four with non- malignant diseases were recruited. Control group comprised 50 apparently healthy subjects of both sexes with age ranging between 18 and 65 years. Serum, pleural and ascitic fluid collections were assayed for total lactate dehydrogenase(LD) and it s isoenzymes. Total LD was estimated using the pyruvate to lactate reaction. LD isoenzyme analysis was estimated by cellulose acetate electrophoresis and stained with formazan. The mean total serum LD activity in the disease groups (malignant and non-malignant) was significantly higher than the mean total serum LD activity in the control group. The pleural fluid LD was highest in patients with empyema thoracis. Five isoenzymes of LD (LD1 - LD5) were present in both control and patient sera. The serum LD1 and LD2 isoenzymes were predominant in the controls. The serum LD4 and LD5 isoenzymes were predominant in the disease groups (malignant and non-malignant). LD4 and LD5 were the predominant isoenzymes in both pleural and ascitic fluids obtained in malignant and non-malignant diseases. Serum LD4 was significantly higher than serum LD5 in non-malignant disease while serum LD5 was significantly higher than serum LD4 in malignant disease. The types of malignancies could not be differentiated by serum and effusion fluid LD isoenzyme pattern. Pleural fluid total LD estimation is useful in monitoring patients on chest tubes and may be used to determine when to insert them. Serum LD4 and LD5 differentiates malignant from non-malignant disease but the effusion LD isoenzyme pattern does not.     

The Imo State (Nigeria) Drinking Water Supply and Sanitation Project, 1. Description of the project, evaluation methods, and impact on intervening variables

A health impact evaluation was conducted in conjunction with the Imo State Drinking Water Supply and Sanitation Project in Nigeria. The project consisted of a package of water supply, sanitation, and health and hygiene education given by village-based workers. The evaluation was a quasi-experimental study covering pre-, peri- and post-intervention periods. Data were collected from 3 intervention and 2 control villages. Baseline surveys indicated that the intervention and control areas were similar with respect to most socio-demographic variables. Use of the improved water supply was high, although this was influenced by borehole-to-population ratios and household-to-borehole distances. Water collection time was consequently greatly reduced. Data from a small sample of households showed that borehole water became heavily contaminated during collection and storage, and that there was no significant change in consumption of water per person. Adults in 46% of household units in the intervention area were using ventilated improved pit latrines by the end of the study period. Use by young children (2-5 years old), however, was low. Limitations in the success of the health education component of the project were found. Although changes were found in knowledge, attitudes and practices related to water and sanitation, and in management of childhood diarrhoea, this occurred in both the intervention and control areas.