Determination of Streptococcus Mutans and Lactobacillus Counts and their Association with Resting pH of Saliva and Dental Caries in Preschool Children in Lagos

BACKGROUND

Caries is controlled by several factors including exposure to diets rich in carbohydrates, tooth susceptibility, and the presence of some oral flora bacteria such as Streptococcus mutans (S. mutans) and Lactobacilli sp. Tooth demineralisation occurs when the pH in the oral cavity is lower than the critical pH of 5.5 which occurs because of the production of acid by the acidogenic bacteria in the oral flora when they break down sugars (substrate) for energy.

OBJECTIVE

The objective of this study was to determine the salivary Streptococcus mutans and Lactobacillus counts and their association with resting pH of saliva and dental caries in pre-school children in Lagos.

MATERIALSAND METHODS

Fifty preschoolers with and without caries were recruited from the dental clinic and staff primary school in Lagos University Teaching Hospital, Idi-araba respectively. Saliva was collected in Thioglycollate media. The resting pH of the saliva was measured immediately in the clinic with a pH meter (Jenway pH meter, PHS 25). In the laboratory, the samples were streaked on Mitis salivarius bacitracin agar (MSB) and Rogosa agar for S. mutans and Lactobacillus respectively and incubated anaerobically for 48 hours at 37°C. Biochemical tests and morphological characteristics of colonies were used to identify S. mutans and Lactobacillus.

RESULTS

The children were aged between 45 to 71 months with a mean age of 56.66 7.17 months. The mean age of the caries-free group was 55.48 7.57 months and that of caries active group was 57.84 6.76 months. The caries-active subjects recorded significantly higher bacterial counts of S. mutans and Lactobacillus compared to the cariesfree subjects. Streptococcus mutans and Lactobacillus showed a negative and highly significant correlation with resting pH (r = - 0.38 and r = - 0.32 value respectively).

CONCLUSION

The resting pH of saliva in both groups was within normal values. Streptococcus mutans and Lactobacillus counts were significantly inversely correlated to the resting pH value of saliva. Streptococcus mutans and Lactobacillus counts were significantly higher in the caries active group.

CONTEXTE

La carie est contrôlée par plusieurs facteurs dont l'exposition à des régimes riches en glucides, la sensibilité des dents et la présence de certaines bactéries de la flore buccale telles que Streptococcus mutans (S. mutans) et Lactobacilli sp.. La déminéralisation des dents se produit lorsque le pH dans la cavité buccale est inférieur au pH critique de 5,5 qui se produit à la suite de la production d'acide par les bactéries acidurogènes dans la flore buccale lorsqu'elles décomposent les sucres (substrat) pour l'énergie.

BUT ET OBJECTIF

L'objectif de cette étude était de déterminer le nombre de Streptococcus mutans et de Lactobacillus et leur association avec le pH au repos de la salive et des caries dentaires chez les enfants d'âge préscolaire à Lagos.

MATÉRIEL ET MÉTHODES

Cinquante enfants d'âge préscolaire avec et sans caries ont été recrutés respectivement à la clinique dentaire et à l'école primaire du personnel de l'hôpital universitaire de Lagos, Idiaraba. La salive a été recueillie dans un milieu au thioglycolate. Le pH au repos de la salive a été mesuré immédiatement en clinique avec un pHmètre (Jenway pH meter, PHS 25).Au laboratoire, les échantillons ont été striés sur gélose bacitracine Mitis salivarius (MSB) et gélose Rogosa pour S. mutans et Lactobacillus respectivement et incubés en anaérobiose pendant 48 heures à 37°C. Des tests biochimiques et des caractéristiques morphologiques des colonies ont été utilisés pour identifier S. mutans et Lactobacillus.

RÉSULTATS

Les enfants étaient âgés de 45 à 71 mois avec un âge moyen de 56,66 ± 7,17 mois. L'âge moyen du groupe sans carie était de 55,48 ± 7,57 mois et celui du groupe avec carie active était de 57,84 ± 6,76 mois. Les sujets actifs carieux ont enregistré un nombre de bactéries significativement plus élevé de S. mutans et Lactobacillus par rapport aux sujets sans caries. Streptococcus mutans et Lactobacillus ont montré une corrélation négative et hautement significative avec la valeur du pH au repos (r = - 0.38 et r = - 0.32 respectivement) .

CONCLUSION

Le pH au repos de la salive dans les deux groupes était dans les valeurs normales. Les numérations de Streptococcus mutans et de Lactobacillus étaient significativement inversement corrélées à la valeur du pH de la salive au repos. Les numérations de Streptococcus mutans et de Lactobacillus étaient significativement plus élevées dans le groupe actif carieux.

Mots-clés

Numération bactérienne, Streptococcus mutans, Lactobacillus, pH delasalive,Enfants d'âgepréscolaire.

Effect of rapid eye movement sleep deprivation during pregnancy on glucocorticoid receptor regulation of HPA axis function in female offspring

Poor maternal sleep quality during the different phases of pregnancy acts as a prenatal stress and is critical for fetal development. Despite the potential adverse effects of maternal stress on the behavior and physiology of the offspring, the mechanisms remain poorly understood. The present study investigates the effects of maternal sleep deprivation (SD) at different stages of pregnancy on the hypothalamic-pituitary-adrenal (HPA) axis in female offspring. The pregnant rats were subjected to sleep deprivation of 12 h per day at different stages; early (ESD), mid (MSD), and late (LSD) stages, on pregnancy days 1-7, 8-14, and 14-20, respectively. At postnatal day 60, levels of corticosterone (CORT), hypothalamic corticotropin-releasing factor receptor 1 (CRF-R1), and hippocampal glucocorticoid receptors (GR) were evaluated in the offspring. Although the hypothalamic CRF-R1 level was increased in the offspring of SD dams, immunohistochemical staining showed reduced immunoreactivity of GR in ESD and LSD offspring hippocampal area. Altogether, the data suggests that a critical period for adverse effects of SD on the HPA axis in female offspring of Wistar rats may be during early and late pregnancy.

Blood pressure, hematologic and biochemical changes following L-arginine supplementation in children with sickle cell anaemia already on hydroxyurea therapy

Hydroxyurea is an approved therapy in the management of children suffering from sickle cell disease (SCD). In adults co-administration of hydroxyurea and L-Arginine in adult sufferers of SCD had shown some benefits. This study examined the effect of co-administration of hydroxyurea (15-35mg/kg/day) and L-Arginine (500 mg/day) for 6 weeks on blood pressure, haematological parameters, liver and antioxidant enzymes levels. The levels of these parameters when the subjects were on hydroxyurea alone were taken as control values. Results showed that the combined therapy (HU + L-Arginine) decreased SBP, DBP, MAP and PP (p <0.01 in each case) but increased %HbF, Hb and PCV (p< o.001 in each case). It elevated CAT, SOD, GPX (p < 0.001 in each case) but depressed MDA, AST, ALT and ALP (p < 0.001 in each case). The study shows that L-Arginine used as an adjunct to hydroxyurea therapy may be beneficial to children suffering from sickle cell anaemia.

Epithelial sodium channel blockade and new β-ENaC polymorphisms among normotensive and hypertensive adult Nigerians

We sought to determine the effect of amiloride on blood pressure (BP) and the presence of polymorphisms of the β-subunit of the epithelial sodium channel (ENaC) among normotensive (NT) and hypertensive (HT) Nigerians. Healthy volunteers-47 NT and 53 age-matched HT were recruited after giving informed consent. Subjects were salt-loaded with 200 mmol of NaCl daily for 5 days. Following a week washout period, salt-loading was repeated in addition to the administration of 5 mg amiloride daily for five days. Blood pressure, plasma and urine electrolytes were measured at baseline, after salt-loading and after salt-loading plus amiloride. PCR amplicons were sequenced for β-ENaC polymorphisms. Salt-loading led to a significant increase (p < 0.05) in SBP among NT and HT and in DBP (p < 0.001) only among HT. Amiloride reduced SBP and DBP to below baseline levels in NT (p < 0.05) and HT (p < 0.001) subjects. Five of the subjects had the β-T594M polymorphism, HT 3/53; NT 2/47 (p = 0.75). Four previously unreported β-ENaC mutations were recorded: E632V and E636V, respectively, among two HT subjects, D638Y in another HT and L628Q in one NT subject. We showed the presence of β-ENaC polymorphisms among our populace and the possible usefulness of amiloride as a single antihypertensive among Nigerians.

Supplementation with l-arginine stabilizes plasma arginine and nitric oxide metabolites, suppresses elevated liver enzymes and peroxidation in sickle cell anaemia

The effect of l-arginine on liver function in SCD has received little or no attention. The effect of a chronic, oral, low-dose supplementation with l-arginine (1gm/day for 6 weeks) on some liver enzymes, lipid peroxidation and nitric oxide metabolites was studied in 20 normal (non-sickle cell anaemia; NSCA) subjects and 20 sickle cell anaemia (SCA) subjects. Ten milliliters of blood was withdrawn from an ante-cubital vein for the estimation of plasma arginine concentration ([R]), alanine aminotransaminase (ALT), aspartate aminotransaminase (AST) and alkaline phosphatase (ALP), plasma total bilirubin concentration [TB], malondialdehyde concentration [MDA] and nitric oxide metabolites concentration [NOx]. Before supplementation, ALT, AST, ALP (p<0.05 respectively) and TB (p<0.001) were higher in SCA subjects than in NSCA subjects. [R] and [NOx] were higher in NSCA subjects (p<0.001 and p<0.05 respectively). Supplementation caused greater percent increases in [R], and [NOX] in SCA than in NSCA subjects (p<0.001 in each case). l-Arginine caused greater percent reductions in ALT and AST in SCA subjects but greater percent reduction in ALP in NSCA subjects (p<0.001 in each case). Changes in [MDA] and [TB] in the two groups were similar. Study shows that chronic, oral, low-dose supplementation with l-arginine improved liver function, oxidative stress, plasma arginine concentration and nitric oxide metabolites levels in NSCA and SCA subjects. Responses in SCA subjects to l-arginine were more sensitive than in NSCA subjects.

Therapeutic Effects of Exercise Training On Selected Cardio-Pulmonary Parameters and Body Composition of Nigerians with Chronic Heart Failure (A Preliminary Study)

BACKGROUND

The use of exercise training in the management of individuals with chronic heart failure has not been widely accepted by health care providers especially in Sub-Saharan Africa because of the possibility that the failing hearts may have a negative response to the increased workload and stress of exercise.

OBJECTIVE

The study aimed to evaluate the effects of exercise training (ET) on selected cardio-respiratory and body composition variables of Nigerians with chronic heart failure (CHF).

METHODS

Thirty two Nigerians with CHF (male - 17), aged 30 to 71 years, mean age 54.2 ± 1.9 years and New York Heart Association Functional Class (NYHA) II-III recruited from Cardiology Clinic of Lagos University Teaching Hospital Nigeria participated in the study. They were randomized into exercise (EG) and control groups (CG). Exercise group performed 12-weeks of aerobic and resistance training for 60 minutes, three sessions per week. Selected cardio-respiratory and body composition variables were measured pre and post intervention in both groups. Data was analyzed using SPSS-17 package. Level of significance was set at 0.05.

RESULTS

There was no significant difference in the measured variables between the groups at baseline (p > 0.05). Significant improvement was seen in EG in all the measured variables except the systolic (p = 0.29) and diastolic blood pressure (p = 0.45). No adverse effect was observed during the exercise training. No significant improvement was observed in the control group (p > 0.05).

CONCLUSION

Exercise training may improve cardiorespiratory and body composition variables in patients with chronic heart failure.

L-arginine increases nitric oxide and attenuates pressor and heart rate responses to change in posture in sickle cell anemia subjects

Pressor and heart rate changes following change in posture without or with L-arginine supplementation (1g/day for 6 weeks) were studied in 28 sickle cell anemia (SCA) and 32 non-sickle cell anemia (NSCA) subjects. Change in posture increased HR (p&lt;0.01), RPP (p&lt;0.05) in both groups of subjects, MABP (p&lt;0.05) in SCAS but reduced MABP (p&lt;0.01) in NSCAS and PP (p&lt;0.01) in SCAS. L-Arginine supplementation increased plasma L-Arginine concentration ([R]) in both groups of subjects (p&lt;0.001 in each group) and serum nitric oxide metabolites concentration ([NOx]) (p&lt;0.01 in each group). Change (Δ) [R] correlated positively with Δ [NOx] in both groups (+ 0.7 in each group). L-Arginine supplementation caused greater reduction of MABP (p&lt;0.001) in NSCAS than in SCAS. However, reduction in HR was greater (p&lt;0.001) in SCAS than in NSCAS. After supplementation, MABP and PP responses to change in posture were attenuated in the two groups. However, while HR and RPP responses in SCAS were attenuated, the same responses were enhanced in NSCAS by change in posture after supplementation. In conclusion, study shows that oral, low dose, chronic supplementation with L-arginine increased NO availability and attenuated pressor and heart rate responses to change in posture in sickle cell anemia subjects.

Exercise training improves walking function in an African group of stroke survivors: a randomized controlled trial

Objective: To evaluate the effects of treadmill walking and overground walking exercise training on recovery of walking function in an African group of stroke survivors.

Design: Prospective, randomized controlled study.

Setting: Outpatient stroke rehabilitation unit in a tertiary hospital.

Subjects: Sixty patients with chronic stroke (≥3 months).

Intervention: All subjects received individual outpatient conventional physiotherapy rehabilitation for 12 weeks. In addition, subjects in Group A ( n = 20) received treadmill walking exercise training (TWET) while those in Group B ( n = 20) received overground walking exercise training (OWET). Those in Group C (control) ( n = 20) received conventional physiotherapy rehabilitation only.

Main measures: Outcome measures were (i) 10-metre walk time (10MWT) test and (ii) six-minute walk distance (6MWD) test. These were evaluated at entry into the study and at the end of every four weeks. Paired t-tests were used to evaluate the significance of the difference between pre-training and post-training scores on the two measures ( P < 0.05).

Results: Subjects in the TWET group recorded 22.6 ± 1.5% decrease in 10MWT and 31.0 ± 4.3% increase in 6MWD; those in the OWET group made 26.8 ± 1.3% and 45.2 ± 4.6% improvement in 10MWT and 6MWD respectively. Subjects in the control group made 2.2 ± 0.7% and 2.9 ± 0.8% improvement in the two functions. These changes were significant for the TWET and OWET groups ( P < 0.05).

Conclusion: This study indicated that treadmill and overground walking exercise training programmes, combined with conventional rehabilitation, improved walking function in an African group of adult stroke survivors. Therefore, professionals who conduct stroke rehabilitation programmes should utilize exercise training to optimize patient outcomes.

Salt-sensitivity in normotensive and hypertensive Nigerians

BACKGROUND

Salt-sensitivity increases the risk for the development of high blood pressure in susceptible persons and also increases the risk for cardiovascular events and mortality.

OBJECTIVE

The study is to determine the pattern of salt-sensitivity among normotensive and hypertensive Nigerians.

METHODS

Twenty-eight (28) hypertensive subjects (HT) and twenty-five (25) age-matched normotensive controls (NT) were given 200 mmol/day salt as sodium chloride for 5 days after control parameters had been determined. Subjects were regarded as salt-sensitive when change in mean arterial blood pressure (cMABP) between baseline levels and that after salt loading was > or = 5 mmHg.

RESULTS

Systolic blood pressure and mean arterial blood pressure but not diastolic blood pressure rose significantly (p < 0.05 and p < 0.001 respectively) in NT subjects while all the parameters showed significant increases in hypertensive subjects (SBP p < 0.01; DBP p < 0.001; MABP p < 0.0001). More hypertensive subjects (60.7%) were salt-sensitive compared with normotensive (52.0%) subjects (p < 0.05).

CONCLUSION

This study has demonstrated pressor responses to acute salt-loading in normotensive and hypertensive Nigerians and salt-sensitivity was higher in hypertensive subjects.

Liver enzymes and trace elements in the acute phase of sickle cell anaemia

BACKGROUND

Trace elements are required for the performance of numerous functions of immune cells. It is not clear whether levels of trace elements are elevated and whether there is a relationship between the levels of liver enzymes and trace elements in patients with sickle cell anaemia in crisis.

OBJECTIVE

To compare the plasma levels of liver enzymes and trace elements in non sickle cell anaemia (NSCA), sickle cell anaemia subjects in the steady state (SCASS) and sickle cell anaemia patients in crisis (SCAC).

METHODS

Haematological parameters, liver enzymes and trace elements were determined in 20 NSCA subjects, 20 SCASS subjects and 18 SCAC subjects. Variables studied included aspartate aminotransferase (AST) , alanine aminotransaminase (ALT), alkaline phosphatase (ALP), and the trace elements copper, zinc, and manganese.

RESULTS

Levels of liver enzymes were higher in the SCAC subjects than in the NSCA or SCASS subjects (p<0.001). Plasma Cu++, Zn++ and Mn++ were also higher in the SCAC subjects than in the NSCA or SCASS subjects (p<0.001). Correlationships were high and strong between AST and ALT (r=+0.7; p=0.03), AST and ALP (r=+0.9; p=0.001), Zn++ and Fe++ (r=+0.9; p=0.001) in SCAC.

CONCLUSION

During crisis in sickle cell anaemia, liver enzymes, as well as the trace elements of Cu++, Zn++ and Mn++ are increased; levels of aspartate aminotransaminase are strongly correlated with those of ALT and ALP. Levels of liver enzymes do not appear to be related to those of the trace elements in painful sickle cell crisis.

Biochemical and histologic changes in rats after prolonged administration of the crude aqueous extract of the leaves of Vitex grandifolia

BACKGROUND

In recent times, many herbal remedies are used to treat variety of ailments. The leaves of Vitex grandifolia is claimed to be effective in the treatment of diabetes mellitus and as a diuretic in the treatment of high blood pressure. However, there are no scientific reports on the therapeutic benefits or toxicity of this plant. This study therefore investigated the effect of prolonged administration of the aqueous extract of the leaves of this plant in Sprague-Dawley rats.

METHODS

The plant leaves (No. FHI 107055) were dried at 40° C, powdered and extracted at room temperature in water (pH 5.72) by percolation. Extract was dried in vacuo to give a yield of 27.32 %w/v. The extract, 0.5-2 g/kg b. wt. was administered by gastric probe to rats for 14 days. The liver and kidney functions, blood chemistry, histopathologic alterations of vital organs and extract effect on rats b. wt. were investigated.

RESULTS

V. grandifolia caused significant increase in the serum electrolytes, creatinine, and liver function enzyme dose dependently compared with the control (P≤ 0.001). The extract had no effect on the heart; however, the architecture of the liver, kidney, and lungs were significantly altered in the treated groups compared with the control. The treated rats had significantly reduced body weight compared with the control (P≤ 0.001). Major clinical signs observed in the treated groups were polydipsia, polyuria, puffiness of hair, and calmness, which were consistent with increase in dose of the extract.

CONCLUSION

It could be clearly concluded that prolonged administration of the aqueous leaf extract of V. grandifolia at the dose used in this study tends to be toxic to the rats. Its use in folkloric medicine should be with utmost care.

Effects of two exercise training techniques on walking function in adult patients with stroke

BACKGROUND

Patients with stroke usually demonstrate activity limitations manifested by reduced ability to perform daily functions.

OBJECTIVE

The purpose of this study was to examine the effects of treadmill walking and overground walking exercise training on walking function in adult patients with stroke.

METHODS

Participants were forty (40) patients with stroke comprising 22 males and 18 females. Inclusion criteria included absence of any co-morbidity that could affect rehabilitation. They were randomly assigned to 2 exercise training groups (20 in each group). All study subjects received conventional physiotherapy rehabilitation for 12 weeks. During the same period, subjects in Group A had treadmill walking exercise training (TWET) while those in Group B had overground walking exercise training (OWET) in addition to the conventional physiotherapy. Outcomes were measured as (i) Ten-metre walk time and (ii) Six-minute walk distance. They were evaluated at entry into the study and at the end of every 4 weeks. Results at weeks 0, 4, 8 and 12 were used for analysis. For each of the 2 groups, paired t-tests were used to evaluate the significance of the differences between the pre-intervention (week 0) mean scores on both tests and the mean scores at weeks 4, 8 and 12.

RESULTS

With 12 weeks of exercise training, both TWET and OWET produced significant improvement in walking function (P < 0.05). However, OWET resulted in significantly greater reduction (26.8%) in mean walking time over 10 metres than TWET (22.6%); and significantly greater increase (45.2%) in mean walking distance over 6 minutes than TWET (31.0%).

CONCLUSION

Exercise training, especially overground walking, could be integrated into the traditional rehabilitation care given to adult patients with stroke.

Electrocardiographic and blood pressure changes in apparently healthy male subjects following oral, chronic, low-dose vitamin C supplementation and/or change in posture

INTRODUCTION

Studies have shown that oral, chronic, low dose vitamin C reduces blood pressure and forearm blood flow in normal young adults or hypertensive patients. It is not clear how vitamin C affects cardiac function or autonomic control of blood pressure in young apparently healthy adults.

AIM

This study was undertaken to examine the effects of a chronic, low dose (300 mg/day for 6 weeks) vitamin C supplementation on the electrocardiogram and autonomic control of blood pressure in apparently healthy male subjects.

METHODOLOGY

Electrocardiographic (ECG) and arterial blood pressure (BP) changes were assessed following change in posture with or without oral, chronic low dose vitamin C supplementation in twenty (20) apparently healthy male subjects (mean age 28.2 +/- 2.0 yrs). Blood pressure (BP, mm Hg) and ECG measurements (amplitude, mV; duration or interval, ms) were recorded in the supine position and immediately on assumption of the upright position. Heart rate (HR; beats/min) was calculated from the ECG while rate pressure product (RPP; arbitrary units) was calculated and used as a measure of myocardial oxygen demand. Each subject was then placed on oral vitamin C at a dose of 300 mg/day for 6 weeks. Measurements were made again after the period.

RESULTS

Change in posture caused significant reductions in P-wave amplitude, QRS amplitude and duration, T-wave amplitude and systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MABP) (p < 0.01 respectively). PR and RR intervals also fell (p < 0.05 and p < 0.001 respectively) while HR and RPP increased (p < 0.001) Vitamin C decreased T-wave amplitude (p < 0.01) and QRS duration (p < 0.01). Also, SBP, DBP, MABP and RPP fell (p < 0.01 in each case). After vitamin C supplement ation, change in posture decreased P-wave amplitude, T-wave duration, P-wave duration, QT interval and RR interval (p < 0.05 respectively). BP and HR responses to postural change were attenuated by vitamin C supplementation. SBP fell by 7.4 +/- 1.0 mm Hg (Vs 12.2 +/-0.1 mm Hg pre-supplementation), DBP by 5.4 +/- 0.6 mm Hg (Vs 10.4 +/- 0.1 mm Hg pre-supplementation) and MABP by 6.1 +/- 1.4 mm Hg (Vs 11.0 +/- 0.1 mm Hg pre-supplementation). HR increased by 18.6 +/- 1.0 beats/min (Vs 29.6 +/- 2.5 beats/min pre-supplementation) and RPP by 1385.6 +/- 126.4 units (Vs 2370.0 +/- 105.6 units pre-supplementation).

CONCLUSION

Chronic, low dose vitamin C supplementation enhanced cardiovascular autonomic activity in apparently healthy young subjects. It minimized the fluctuations in BP and HR and also reduced myocardial oxygen demand following postural change.

Vasorelaxant action of aqueous extract of the leaves of Persea americana on isolated thoracic rat aorta

The present study investigated the vasorelaxant action of the aqueous leaves extract of Persea americana on isolated rat aorta. The results showed that the extract produced significant vasorelaxation and that the effect is dependent on the synthesis or release of endothelium-derived relaxing factors (EDRFs) as well as the release of prostanoid. The extract also reduced vasoconstriction probably by inhibiting Ca2+ influx through calcium channels.

Effect of changes in plasma vitamin E level of vascular responses and lipid peroxidation in sickle cell anaemia subjects

The effect of vitamin E supplementation (300 mg/day for 6 weeks) on blood pressure, forearm blood flow, forearm vascular resistance, plasma vitamin E level and lipid peroxidation status was investigated in adult sickle cell anaemia subjects. Ten adults whose ages ranged from 19.0 to 25.0 years (mean 22.8+/-0.8 years) were studied. Vitamin E supplementation had little or no effect on arterial blood pressure but significantly increased forearm blood flow (p<0.001) and plasma vitamin E level (p<0.001). However it significantly decreased lipid peroxidation status (p<0.001) and forearm vascular resistance (p<0.001). The change in plasma vitamin E concentration correlated negatively with change in lipid peroxidation status (r=-0.8; p=0.003). However, change in plasma vitamin E concentration correlated positively with change in forearm blood flow (r=0.8; p=0.006). There was an inverse correlation between change in plasma lipid peroxidation and change in forearm blood flow (r=-0.7; p=0.03). The study therefore shows that in sickle cell anaemia subjects, vitamin E supplementation increases forearm blood flow and reduces forearm vascular resistance and lipid peroxidation. The increase in forearm blood flow correlates inversely with the reduction in lipid peroxidation. This suggests that in sickle cell anaemia subjects, vitamin E supplementation could cause an increase in forearm blood flow by decreasing plasma lipid peroxidation level.

Changes in erythrocytes following supplementation with alpha-tocopherol in children suffering from sickle cell anaemia

INTRODUCTION

Low plasma vitamin E level in children with sickle cell anaemia has been related to elevated level of irreversibly sickled cells which has been implicated in the pathogenesis of painful crisis. In adult patients supplementation with alpha-tocopherol has been shown to reduce irreversibly sickled cell count. In-addition, vitamin E supplementation increases resting forearm blood flow and reduces forearm vascular resistance in adult sickle cell anaemia sufferers.

AIM

The aim of the study was to examine the effects of supplementation with alpha-tocopherol on arterial blood pressure, some haematological parameters and osmotic fragility in children suffering from sickle cell anaemia.

METHODOLOGY

The effects of supplementation with alpha-tocopherol (100 mg. per day for 6 weeks) on packed cell volume (PCV) haemoglobin concentration ([Hb]), mean corpuscular haemoglobin concentration (MCHC), per cent foetal haemoglobin (% HbF), per cent irreversibly sickled cells (%ISC), erythrocyte osmotic fragility and blood pressure have been assessed in ten (10) children suffering from sickle cell anaemia. Their ages ranged from 4.0 to 10.0 years.

RESULTS

Supplementation with alpha-tocopherol significantly increased packed cell volume (p<0.001), haemoglobin concentration (p<0.01) and per cent foetal haemoglobin (p<0.001), but significantly reduced mean corpuscular haemoglobin concentration (p<0.01) and per cent irreversibly sickled cells (p<0.001). alpha-Tocopherol also increased the resistance of the cells to lysis. Supplementation with alpha-tocopherol had little or no effect on arterial blood pressure.

CONCLUSION

This study shows that short-term supplementation with alpha-tocopherol may be beneficial to the paediatric sickle cell sufferer.

The effect of warmth or/and vitamin E supplementation on forearm blood flow and forearm vascular resistance in sickle cell and non sickle cell anaemia subjects

The effects of warmth stimulation and/or supplementation with vitamin E (300 mg/day for 6 weeks) on forearm blood flow (FBF) and forearm vascular resistance (FVR) were measured in 8 sickle cell anaemia (SCA) (mean age = 22.8 + 0.8 years) and 11 non sickle cell anaemia (NSCA) subjects (mean age = 23.2 + 1.1 years) of both sexes. Warmth stimulation was induced by immersing the left foot in warm water at 400C for 2 minutes. Forearm blood flow was measured with the venous occlusion plethysmography method. Warmth increased FBF (p <0.01 in each group) and reduced FVR (p <0.05) in NSCA subjects. The change in FBF was greater (p < 0.05) in the NSCA subjects than in the SCA subjects. Supplementation with vitamin E reduced systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) (p < 0.001 in each case) in the NSCA subjects but had little or no effect on the SCA subjects. Vitamin E increased FBF in NSCA subjects (p < 0.05) and SCA subjects (p < 0.01) and decreased FVR in both groups (p < 0.05 in NSCA and p < 0.01 in SCA subjects). The change in FVR seen in the NSCA subjects was less (p < 0.01) than the change in SCA subjects. After supplementation with vitamin E, warmth further decreased SBP (p < 0.01 in each group) and FVR (p < 0.01 in each case) and increased FBF in both groups (p < 0.01 respectively). The changes caused by warmth after vitamin E supplementation on the blood pressure parameters, FBF and FVR were similar in the two groups of subjects.

Blood pressure, hematologic and erythrocyte fragility changes in children suffering from sickle cell anemia following ascorbic acid supplementation

The effect of ascorbic acid supplementation (100 mg/day for 6 weeks) on blood pressure, packed cell volume, irreversibly sickled cells, per cent fetal hemoglobin, hemoglobin concentration, and erythrocyte osmotic fragility was assessed in children suffering from sickle cell anemia. Fifteen children whose ages ranged from 4 to 11 years (7.5 +/- 0.75 years) were studied. Ascorbic acid supplementation reduced systolic blood pressure by 10.9 +/- 3.4 mmHg (p < 0.01), diastolic blood pressure by 7.3 +/- 2.0 mmHg (p < 0.01) and mean arterial pressure by 9.4 +/- 2.6 mmHg (p < 0.01). It significantly increased packed cell volume (p < 0.001), hemoglobin concentration (p < 0.001) and per cent fetal hemoglobin (p < 0.001), but reduced per cent irreversibly sickled cells (p < 0.001). Ascorbic acid supplementation also abolished the long tail of the erythrocyte osmotic fragiligram and increased the resistance of the cells to lysis.

Exercise improves recovery of ventilation in male asthmatic subjects in the steady state

The effect of a three-minute exercise step test (submaximal) on the recovery of tidal volume (V(T)), respiratory frequency (f(R)) and minute ventilation (V(E)) has been investigated in non-asthmatic subjects, asthmatic subjects that exercise regularly and asthmatics that do not participate in regular exercise. Recovery was observed over twenty minutes at two-minute intervals. Ten male non-asthmatic subjects (NAS) (mean age 20.7+/- 0.4 yr), six male asthmatic subjects (20.5+/- 0.5 yr) that exercised regularly (EAS) and six male asthmatic subjects (20.8+/- 0.5 yr) that did not exercise regularly (NEAS) were studied. Exercise significantly increased all the measured variables in all the groups of subjects (P<0.001 in each case). At the end of the 20th minute, magnitude of recovery of V(T) was 123.3+/- 4.5% in NAS, 102.4+/- 5.1% in EAS (p<0.001) and 87.9+ 5.4% in NEAS (p<0.001). Mean rate of recovery of V(T) was highest (6.3%/min) in NAS and least in NEAS (4.4%/min). At the end of the (T)observation period, recovery of respiratory frequency (f(R)) was 100.0+/- 5.0% in NAS, 100.0+/- 4.5% in EAS and 89.2+/- 3.0 in NEAS. Mean rate of recovery of f(R) was 5.0%/min in NAS and EAS subjects respectively and 4.4%/min in NEAS subjects. Also, at the end of the 20th minute, the magnitude of recovery of V(E) was similar between NAS and EAS (105.1+/- 1.5% and 101.6+/- 1.75% respectively). Recovery of V(E) was significantly less in NEAS (93.9+/- 2.5%; p<0.01). Mean rate of recovery of V(E) was similar between NAS and EAS subjects (5.0%/min in each case) and 4.1%/min in the NEAS subjects. Thus regular exercise improves the recovery of ventilatory parameters in asthmatic subjects.

The effect of vitamin C and/or warmth on forearm blood flow and vascular resistance in sickle cell anaemia subjects

This study seeks to examine the effects of vitamin C supplementation or/and warmth on forearm blood flow (FBF) and forearm vascular resistance (FVR) in sickle cell anaemia (SCA) subjects in the steady state. Sixteen (16) SCA subjects of both sexes (mean age, 23.4+/-1.5 yrs.) were studied. Blood pressure (BP, mm Hg) and FBF (ml/min) measurements were made at rest, with warmth stimulation, after vitamin C supplementation for 6 weeks at 300 mg per day and with warmth stimulation after vitamin C supplementation. Warmth stimulation was induced by immersing the left foot in a bowl of water at a temperature of 40 degrees C for 2 minutes. Forearm blood flow (FBF) [corrected] was measured by means of a forearm plethysmograph. Forearm vascular resistance (FVR, arbitrary units) was calculated by dividing mean arterial pressure (MAP) with FBF. Warmth stimulation at 40 C significantly decreased systolic blood pressure (SBP) (p<0.05), diastolic blood pressure (DBP) (p<0.01), MAP (p<0.01) and FVR (p<0.01) but significantly increased FBF (p<0.01). Vitamin C supplementation also significantly reduced SBP (p<0.001), DBP (p<0.01), MAP (p<0.01) and FVR (p<0.05) but significantly increased FBF (p<0.01). After vitamin C supplementation, warmth stimulation potentiated the reduction in SBP (p<0.001), DBP (p<0.01), FVR (p <0.01) and increase in FBF (p<0.01). In conclusion, warmth stimulation at 40 [corrected] degrees C or vitamin C supplementation caused a decrease in arterial blood pressure, forearm vascular resistance and increase in forearm blood flow in sickle cell anaemia subjects. Pretreatment with vitamin C enhanced the vasodilator effect of warmth.

Lung function, haemoglobin and irreversibly sickled cells in sickle cell patients

This study seeks to show whether there is a positive relationship between HbF, irreversibly sickled cells and several lung function parameters. Percentage haemoglobin F (%HbF), percent irreversibly sickled cells (%ISC), blood pressure (BP, mm Hg), heart rate (HR, b/min), forced vital capacity (FVC,I), timed vital capacity (FEV1, I) FEV1% and peak expiratory flow rate (PEFR, I/min) were measured in 10 sickle cell (in the steady state) and 15 non-sickle cell subjects matched by age and sex. Results showed that although the ages in both groups of subjects were similar, sickle cell anaemia (SCA) subjects had smaller stature. Diastolic BP was significantly lower while pulse pressure, %Hbf and %ISC were significantly higher in SCA subjects (P < 0.001 in each case). Predicted FVC, FEV1, and PEFR were significantly higher (P < 0.01, P < 0.01, P < 0.001 in each case) than observed values obtained from SCA subjects. Similarly, measured FVC, FEV1, and PEFR in SCA subjects were significantly lower (P < 0.001 respectively) than values obtained from non-sickle cell subjects. In SCA subjects, %HbF or %ISC correlated negatively with each of the ventilatory parameters and with each other. Similar results (except for PEFR) were obtained in the non-sickle cell subjects. The results suggest that %HbF and %ISC correlate negatively with lung function parameters in sickle cell sufferers in the steady state.

Peak expiratory flow rate in Nigerian school children

Peak expiratory flow rate (PEFR) was measured using the Wright's peak flow meter in 263 school boys and 275 school girls living in Lagos, Nigeria. Their ages ranged from 6.0 years to 19.0 years (mean 11.9 +/- 3.8 yrs. for boys and 11.8 +/- 3.9 yrs. for girls). Mean PEFR was 359.2 +/- 102.0 L/min (range 160.0-610.0 L/min) in boys and 327.7 +/- 81.3 L/min (range 160.0-500.0 L/min) in girls. Apart from ages 17, 18 and 19, peak expiratory flow rates were similar in both boys and girls. In both sexes, PEFR correlated positively and significantly with age, height, weight and body surface area. Also in both sexes and in all age groups studied, PEFR was significantly higher than predicted values obtained from previous Nigerian and caucasian prediction equations. When compared with values obtained from a second caucasian prediction equation, observed values were significantly higher in the 6-10 years and 16-19 years age groups in boys and 11-15 years and 16-19 years age groups in girls. New prediction equations for calculating PEFR in Nigerian boys and girls are presented. Observed PEFR may be due to enhanced stature in Nigerian children resulting from improved environment and genetic factors.

Lung function in young Nigerian adults

Static and dynamic long volumes have been measured in 181 (123 males and 58 females) apparently healthy Nigerian adults. The age range in both sexes was between 17 and 34 years (22.0 +/- 3.2 years in males and 21.3 +/- 3.2 years in females). In the male subjects mean height, weight and body surface area were 170.0 +/- 6.0 cm, 62.0 +/- 8.5 kg and 1.72 +/- 0.19 m2 respectively. In the female subjects mean height, was 162.3 +/- 15.3 cm, mean weight was 57.2 +/- 8.4 kg and mean body surface area was 1.60 +/- 0.12 m2. In both sexes, caucasian prediction formulae overestimated the TLC, FVC and RV/TLC% of the subjects. Observed FEV % in our subjects was higher than in the caucasians. The elevated FEV1 % and reduced FVC, RV/TLC % and TLC in Nigerian subjects may suggest and increased elastic recoil of the lungs and chestwall in them. Regression coefficients and constants for predicting TLC, FVC, FEV1, IC, ERV and RV in Nigerian subjects are presented.