- Medical Scientistedit
Objective To determine the histological effects of different frequencies of loading in a healing Achilles tendon following partial rupture. Design Experimental laboratory study. Setting University of Zimbabwe, Department of Physiology,... more
Objective To determine the histological effects of different frequencies of loading in a healing Achilles tendon following partial rupture. Design Experimental laboratory study. Setting University of Zimbabwe, Department of Physiology, Animal house. Subjects Sixty female Sprague-Dawley rats. Intervention Partial tenotomies of the right Achilles tendon were performed surgically. From day 1 post operatively, the animals were allocated to treadmill running at different frequencies (once (OD), two (BD), three (TDS) and four (QID) times daily) up to 21 days. Histological sides of the tendons were made at days 7,14 and 21 and interpreted by a blinded pathologist. Main outcome measures Collagen fibre orientation, inflammatory cell populations, fibroblast morphology and neoangiogenesis were observed and scored using the Grande Biomechanical Histological Correlation Score. Results Mean weight was 209.67g ±30.14. The best and worst arrangements of collagen were in the QID group (73%) and OD g...
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Pain, the most urgent of symptoms usually signals the presence of potential or on-going injury to tissue which requires attention. The warning that pain provides is, therefore, a good thing and in a way friendly. When pain continues or... more
Pain, the most urgent of symptoms usually signals the presence of potential or on-going injury to tissue which requires attention. The warning that pain provides is, therefore, a good thing and in a way friendly. When pain continues or resumes after the healing process of injury is complete, it is no longer signalling on-going tissue damage but becomes a disease in its own right. That, in essence, is the presentation of most chronic pain syndromes referred to Pain Clinics for investigation and treatment.
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Satisfactory progress and examination results have been reported for the first four candidates studying for the University of Zimbabwe's new Master of Medicine degree in Anesthetics
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The increase in the amplitude of the E.C.G. and ventricular contractile force induced by chloroquine sulphate was studied in frogs. It was shown that changes originated in the midbrain and were mediated through the sympathetic nervous... more
The increase in the amplitude of the E.C.G. and ventricular contractile force induced by chloroquine sulphate was studied in frogs. It was shown that changes originated in the midbrain and were mediated through the sympathetic nervous system. The transmitter was recognized as a beta-adrenergic agent. The possible mechanism of action of chloroquine on the CNS responsible for the phenomenon observed was discussed.
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Paper presented at the International summit on past and present research systems of green chemistry;August 25-27, 2014 Hilton Philadelphia Airport, USA
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The movement of people during some of their daily occupations and activities releases an amount of dust into the air. Even dust that has settled on floors and flat surfaces is made airborne by air currents. Of greater concern is the dusty... more
The movement of people during some of their daily occupations and activities releases an amount of dust into the air. Even dust that has settled on floors and flat surfaces is made airborne by air currents. Of greater concern is the dusty environment caused by the operations within the workplace, such as handling of dusty materials, machining, cutting, drilling, milling, rock blastic and pounding. Fortunately, a lot of the dust is harmless except when present in high concentrations when it can cause some discomfort. At such levels it is termed 'nuisance dust'. However, some form of dusts are distinctly harmful, giving rise to impairment of lung function and pneumoconiosis (dust-induced changes in the lung).
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Two neonates suffered from generalized seizures during the course of intravenous morphine sulfate for post-operative analgesia. They received morphine in doses of 32 micrograms/kg/hr and 40 micrograms/kg/hr larger than a group of 10... more
Two neonates suffered from generalized seizures during the course of intravenous morphine sulfate for post-operative analgesia. They received morphine in doses of 32 micrograms/kg/hr and 40 micrograms/kg/hr larger than a group of 10 neonates who received 6-24 micrograms/kg/hr and had no seizures. Plasma concentrations of morphine in these neonates was excessive (60 and 90 mg/ml). Other known reasons for seizures were ruled out and the convulsions stopped a few hours after cessation of morphine and did not reoccur in the subsequent 8 months. It is suggested that post-operative intravenous morphine should not exceed 20 micrograms/kg/ml in neonates.
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Three cases in which aneurysms were misdiagnosed to less serous lesions are described. Attention is drawn to the possibility of these errors whose consequences can be fatal. Some of the problems associated with the handling of an... more
Three cases in which aneurysms were misdiagnosed to less serous lesions are described. Attention is drawn to the possibility of these errors whose consequences can be fatal. Some of the problems associated with the handling of an inadvertently opened aneurysm are discussed.
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Research Interests: Plant Biology and Ecology
We measured and compared lung function indices and some blood parameters (gases, electrolytes, glucose, pH, red cell indices) of 54 male small-scale miners (SSM) chronically exposed to chrome ore dust to those of 50 nonmining control... more
We measured and compared lung function indices and some blood parameters (gases, electrolytes, glucose, pH, red cell indices) of 54 male small-scale miners (SSM) chronically exposed to chrome ore dust to those of 50 nonmining control subjects (NMC) and 46 large-scale chrome miners (LSM) who had taken internationally recommended precautionary measures (secondary control). The respirable dust level in the SSM environment (6.0 +/- 0.5 mg/m3) was significantly higher (P < 0.001) than in the NMC and LSM environments (0.3 +/- 0.1 mg/m3 and 0.5 +/- 0.3 mg/m3, respectively). There were no significant differences in neither dust levels nor lung function status between NMC and LSM environments. The values of FVC, FEV1, PEFR and FEV1% of the SSM were 3.5 +/- 0.09 l, 2.61 +/- 0. 09 l, 6.07 +/- 0.36 l/second and 76.19 +/- 2.36%, respectively. These values were significantly lower than those of NMC (P < 0.01, respectively). However, the blood parameters of the SSM and NMC were not significantly different. The results are indicative of both restrictive and obstructive ventilatory defects in the SSM which may be attributed exposure to chrome ore dust in the environment. Associated risk factors appear to be advancing age, prolonged exposure to chrome ore dust and acid base disturbance.
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In this report we describe a rapid and sensitive micromethod using high performance liquid chromatography (HPLC) with electrochemical detection (ED) to measure morphine concentration in serum or plasma. The separation of morphine and the... more
In this report we describe a rapid and sensitive micromethod using high performance liquid chromatography (HPLC) with electrochemical detection (ED) to measure morphine concentration in serum or plasma. The separation of morphine and the internal standard 5-hydroxyquinoline, from interfering compounds present in plasma was achieved by paired-ion reverse phase chromatography using a 70 mM phosphate buffer at pH 5.80. The flow rate was 1 ml/min. Oxidation of morphine and the internal standard was obtained at a potential of 0.60 V. Only 100 microliter of serum or plasma was required. Analytical recoveries for morphine and 5-hydroxyquinoline were determined as 78% and 63% respectively. The between-day precision of serum samples containing 250, 100, and 25 microgram/L of morphine (n = 20) was 6.5%, 5.2%, and 9.5% respectively. The detection limit was determined as 1 microgram/L at a sensitivity of 5 nA/V. In our preliminary studies, 3 children between the ages of 0 and 5 years received a bolus of morphine of 11 microgram/kg, followed by an infusion of 2 microgram/kg/min during surgery. The time-concentration curves demonstrate an initial rapid fall in morphine concentration with subsequent attainment of a steady state concentration of approximately 90 microgram/L after 1 h. This concentration would be expected to produce optimal analgesia in conscious patients.
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Research Interests: Thermoregulation, Anesthesiology, Aging, Humans, Circadian Rhythm, and 15 moreHypothalamus, Anesthesia, Temperature, Muscles, Thyroxine, Body temperature regulation, Body Temperature, Anesthetics, Dehydration, Fever, Operating Rooms, Sympathetic Nervous System, Biological activity, Temperature Regulation, and Pharmacology and pharmaceutical sciences
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There are a number of reports from traditional medical practice in Zimbabwe and neighboring countries and few in vitro studies suggesting an effect with extracts of Boophone disticha in some forms of anxiety disorder. In order to validate... more
There are a number of reports from traditional medical practice in Zimbabwe and neighboring countries and few in vitro studies suggesting an effect with extracts of Boophone disticha in some forms of anxiety disorder. In order to validate the use of Boophone disticha in treatment of anxiety, this study was set to determine the effects of the plant extracts on blood pressure (BP) and heart rate (HR) in adult BALB/c mice subjected to repeated early maternal separation (MS) stress. To test whether early life stress increases anxiety in mice, non-invasive tail cuff method was used to examine the autonomic nervous system activity by assessing cardiovascular reactivity and response to acute mixing stress (AMS) and restraint stress (RS) in adult mice subjected to early postnatal stress as compared to control. AMS-induced cardiovascular response was then evaluated in adult MS mice treated with Boophone disticha as compared to vehicle and diazepam. Comparisons of the BP and HR measurements indicated that MS significantly reduced AMS-induced HR responses in BALB/c mice when compared with control. Boophone disticha treatment significantly reduced AMS-induced BP response in BALB/c MS mice as compared to vehicle and diazepam treatments. Our findings demonstrate for the first time that postnatal stress can induce short-term changes in the sensitivity of the cardiovascular system to subsequent stress which can be reduced by treatment with a freeze dried aqueous ethanolic extract of Boophone disticha.
Research Interests: Water, Complementary and Alternative Medicine, Plant Biology, Ethnopharmacology, Anxiety, and 15 moreAutonomic Nervous System, Zimbabwe, Mice, Blood Pressure, Female, Animals, Divorce, Ethanol, Heart rate, Cardiovascular system, Plant extracts, ANXIETY, Liliaceae, Maternal Deprivation, and Pharmacology and pharmaceutical sciences
Intravenous morphine in combination with muscle relaxants, nitrous oxide, and oxygen in so-called balanced anesthesia is commonly used in children between the ages of 0 and 5 yr during surgery. We define dosing rules for a loading dose... more
Intravenous morphine in combination with muscle relaxants, nitrous oxide, and oxygen in so-called balanced anesthesia is commonly used in children between the ages of 0 and 5 yr during surgery. We define dosing rules for a loading dose followed by a continuous intravenous infusion of morphine sulfate to achieve a serum morphine concentration of 75 micrograms/L. This concentration is well above the minimum serum morphine concentration of 50 micrograms/L for moderate analgesic effects in adults. It also exceeds the concentration of 65 micrograms/L claimed to provide adequate analgesia in children during surgery. The clearance of morphine in 8 children between 0 and 5 yr of age was 20.5 +/- 2.8 mL/kg/min (means +/- SD). This result is threefold larger than the clearance value obtained after a single intravenous dose and 1.5 times greater than clearance values found after multiple intravenous doses of morphine, previously reported by others in children between the ages of 1 and 15 yr. Having established a dosing regimen that achieves a steady-state serum morphine concentration of approximately 75 micrograms/L, we plan to investigate the relationship between morphine serum concentration and pharmacologic effect. Intraoperatively the action of morphine at its receptor site will be assessed according to a scoring system including EEG changes, heart rate, blood pressure, response to sensory stimuli, and maintenance of vital functions. The effect of intravenous morphine will further be estimated according to the postanesthetic scoring system described in this report. Using intraoperative and postanesthetic scores to evaluate the pharmacodynamics of morphine for anesthesia in relation to morphine serum concentration will lead to a better understanding and improvement in use of intravenous morphine in young children.
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The objective of the study was to compare the change in diastolic function, E/A ratio, in response to prolonged exercise in low birth weight and normal birth weight individuals. Using a case–control study design, 23 students of the... more
The objective of the study was to compare the change in diastolic function, E/A ratio, in response to prolonged exercise in low birth weight and normal birth weight individuals. Using a case–control study design, 23 students of the University of Zimbabwe College of Health Sciences who had neonatal clinic cards as proof of birth weight were recruited into the study. Measurements of diastolic function, E/A ratio, were obtained using an echocardiogram before and after 75 minutes of exercise. Among the cohort, seven had low birth weight – <2500 g, three female patients and four male patients – and 16 had normal birth weight – six female patients and 10 male patients). The mean age was 20.7±3.3 years. After prolonged exercise for 75 minutes of running on a treadmill, decreases in diastolic function, E/A ratio, were significantly greater in low birth weight than in normal birth weight individuals (0.48±0.27 versus 0.19±0.18 p<0.05, respectively). There was a significant association ...
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Research Interests: Adolescent, Methods, Humans, Child, Female, and 8 moreMale, Anesthesia, Infant, Clinical Sciences, Adult, Blood gas analysis, Child preschool, and Larynx
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We determined the minimum effective anesthetic concentration (MEAC) of bupivacaine for spinal anesthesia, defined as the median effective concentration at which a spinal anesthetic produces surgically equivalent anesthesia within 20 min... more
We determined the minimum effective anesthetic concentration (MEAC) of bupivacaine for spinal anesthesia, defined as the median effective concentration at which a spinal anesthetic produces surgically equivalent anesthesia within 20 min of administration in 50% of human subjects. Two doses of spinal bupivacaine (7.5 mg and 10 mg) were administered to 45 volunteers (19-39 yr) in a randomized, double-blinded fashion. Hyperbaric bupivacaine solutions of 0.1% to 0.75% containing 8.25% dextrose were administered intrathecally and MEAC established by using the Dixon&#39;s up-and-down method. Complete anesthesia was defined as: 1) pinprick anesthesia at or higher than T12; 2) anesthesia to transcutaneous tetanic electric stimulation (50 Hz at 60 mA for 5 s) in the knees; and 3) complete leg paralysis, all occurring in both lower extremities within 20 min of intrathecal injection. We found that the MEAC of spinal bupivacaine was 0.43% (95% confidence interval 0.24-0.62) when 10 mg was administered. At this dose, a concentration as low as 0.1% could provide complete anesthesia, but consistent blockade was obtained only with the 0.7% solution. The 7.5-mg dose failed to provide complete anesthesia consistently, even in the presence of 0.75% (maximum). The current commercially available 0.75% concentration of hyperbaric bupivacaine seems to be clinically optimal when 10 mg is used if complete bilateral lower extremity blockade is desired.