Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Durban University of Technology, 2009. / The Effect of Cervical and Thoracic Spinal Manipulations on Blood Pressure in Normotensive Males. BACKGROUND A distinguishing feature of chiropractic is manipulation that is a load delivered by hand, to specific tissues (usually a short lever bony prominence) with therapeutic intent. Chiropractic spinal manipulation results in somatovisceral reflexes, which can affect the cardiovascular system and thereby reduce blood pressure. Areas of the spine known to cause such effects are the upper cervical region and the upper thoracic region. Increased blood pressure/hypertension is a global disorder. The incidence is increasing and leads to complications of cardiovasular disease and cerebral vascular accidents OBJECTIVES The objectives of the study were to determine whether spinal manipulation evokes somatovisceral reflexes and causes a reduction in blood pressure following an atlanto-axial (C0/C1), and Thoracic segments one to five manipulations (T1-T5). METHODS Forty, asymptomatic, normotensive males between the ages of 20 – 35 years of age participated in the study. All subjects underwent four consecutive days of intervention. Day one was sham laser. Day two was C0/C1 spinal manipulation. Day three was T1-T5 thoracic manipulation. Day four was a combination of C0/C1 and T1-T5 spinal manipulations. RESULTS The results of this study suggest that blood pressure decreases following a cervical or a thoracic manipulation, however a combination of the manipulations does not have a significant cumulative effect on the reduction of blood pressure. iv CONCLUSIONS Somatovisceral reflexes are evoked following a spinal manipulation, causing a reduction in blood pressure after an upper cervical or upper thoracic manipulation. Neurophysiological effects occurring as a result of spinal manipulation may inhibit or excite somatosomatic reflexes, which changes heart rate and blood pressure. / Aaron Bear Foundation

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Any branch in science experiences measurement error to some extent. This maybe due to conditions under which measurements are taken, which may include the subject, the observer, the measurement instrument, and data collection method. The inexactness (error) can be reduced to some extent through the study design, but at some level further reduction becomes difficult or impractical. It then becomes important to determine or evaluate the magnitude of measurement error and perhaps evaluate its effect on the investigated relationships. All this is particularly true for blood pressure measurement. The gold standard for measunng blood pressure (BP) is a 24-hour ambulatory measurement. However, this technology is not available in Primary Care Clinics in South Africa and a set of three mercury-based BP measurements is the norm for a clinic visit. The quality of the standard combination of the repeated measurements can be improved by modelling the measurement error of each of the diastolic and systolic measurements and determining optimal weights for the combination of measurements, which will give a better estimate of the patient's true BP. The optimal weights can be determined through the method of structural equations modelling (SEM) which allows a richer model than the standard repeated measures ANOVA. They are less restrictive and give more detail than the traditional approaches. Structural equations modelling which is a special case of covariance structure modelling has proven to be useful in social sciences over the years. Their appeal stem from the fact that they includes multiple regression and factor analysis as special cases. Multi-type multi-time (MTMT) models are a specific type of structural equations models that suit the modelling of BP measurements. These designs (MTMT models) constitute a variant of repeated measurement designs and are based on Campbell and Fiske's (1959) suggestion that the quality of methods (time in our case) can be determined by comparing them with other methods in order to reveal both the systematic and random errors. MTMT models also showed superiority over other data analysis methods because of their accommodation of the theory of BP. In particular they proved to be a strong alternative to be considered for the analysis of BP measurement whenever repeated measures are available even when such measures do not constitute equivalent replicates. This thesis focuses on SEM and its application to BP studies conducted in a community survey of Mamre and the Mitchells Plain hypertensive clinic population. / AFRIKAANSE OPSOMMING: Elke vertakking van die wetenskap is tot 'n minder of meerdere mate onderhewig aan metingsfout. Dit is die gevolg van die omstandighede waaronder metings gemaak word soos die eenheid wat gemeet word, die waarnemer, die meetinstrument en die data versamelingsmetode. Die metingsfout kan verminder word deur die studie ontwerp maar op 'n sekere punt is verdere verbetering in presisie moeilik en onprakties. Dit is dan belangrik om die omvang ven die metingsfout te bepaal en om die effek hiervan op verwantskappe te ondersoek. Hierdie aspekte is veral waar vir die meting van bloeddruk by die mens. Die goue standaard vir die meet van bloeddruk is 'n 24-uur deurlopenee meting. Hierdie tegnologie is egter nie in primêre gesondheidsklinieke in Suid-Afrika beskikbaar nie en 'n stel van drie kwik gebasseerde bloedrukmetings is die norm by 'n kliniek besoek. Die kwaliteit van die standard kombinasie van die herhaalde metings kan verbeter word deur die modellering van die metingsfout van diastoliese en sistoliese bloeddruk metings. Die bepaling van optimale gewigte vir die lineêre kombinasie van die metings lei tot 'n beter skatting van die pasiënt se ware bloedruk. Die gewigte kan berekening word met die metode van strukturele vergelykings modellering (SVM) wat 'n ryker klas van modelle bied as die standaard herhaalde metings analise van variansie modelle. Dié model het minder beperkings en gee dus meer informasie as die tradisionele benaderings. Strukurele vergelykings modellering wat 'n spesial geval van kovariansie strukturele modellering is, is oor die jare nuttig aangewend in die sosiale wetenskap. Die aanhang is die gevolg van die feit dat meervoudige lineêre regressie en faktor analise ook spesiale gevalle van die metode is. Meervoudige-tipe meervoudige-tyd (MTMT) modelle is 'n spesifieke strukturele vergelykings model wat die modellering van bloedruk pas. Hierdie tipe model is 'n variant van die herhaalde metings ontwerp en is gebaseer op Campbell en Fiske (1959) se voorstel dat die kwaliteit van verskillende metodes bepaal kan word deur dit met ander metodes te vergelyk om sodoende sistematiese en stogastiese foute te onderskei. Die MTMT model pas ook goed in by die onderliggende fisiologies aspekte van bloedruk en die meting daarvan. Dit is dus 'n goeie alternatief vir studies waar die herhaalde metings nie ekwivalente replikate is nie. Hierdie tesis fokus op die strukturele vergelykings model en die toepassing daarvan in hipertensie studies uitgevoer in die Mamre gemeenskap en 'n hipertensie kliniek populasie in Mitchells Plain.

High consumption of dairy products, particularly non-fat dairy, is associated with reduced risk of high blood pressure and vascular dysfunction. Currently, it is not known if the solitary addition of conventional non-fat dairy products to the normal routine diet is capable of reducing blood pressure or improving vascular function. Accordingly, the primary aims of the present study were to determine if the solitary addition of conventional non-fat dairy products to the normal routine diet would reduce blood pressure and improve vascular function in middle-aged and older adults with elevated blood pressure. Using a randomized, crossover intervention study design, forty-nine adults with elevated blood pressure underwent a High Dairy condition (+4 servings/day of conventional non-fat dairy products) and isocaloric No Dairy condition (+4 servings/day fruit products) in which all dairy products were removed. Both dietary conditions lasted 4 weeks with a 2-week washout before crossing over into the alternate condition. In Study 1, the High Dairy condition produced reductions in brachial systolic blood pressure and pulse pressure. The hypotensive effects were observed within three weeks after the initiation of dietary intervention and in both casual seated and ambulatory (24-hour) measurements. On the contrary, pulse pressure was increased after removal of all dairy products in the No Dairy condition compared to baseline and after in the High Dairy condition. There were no changes in diastolic blood pressure after either dietary condition. In Study 2, the High Dairy condition produced reductions in carotid systolic blood pressure, pulse pressure, and carotid-femoral pulse wave velocity with a concomitant increase in brachial flow-mediated dilation and cardiovagal baroreflex sensitivity. Brachial flow-mediated dilation decreased and carotid pulse pressure increased after removal of all dairy products in the No Dairy condition. Furthermore, [delta] carotid systolic blood pressure and carotid-femoral pulse wave velocity were highly related. Taken together, we concluded that the solitary manipulation of conventional dairy products, particularly non-fat dairy, in the normal routine diet would modulate levels of blood pressure and vascular function in middle-aged and older adults with pre-hypertension and hypertension. / text

A descriptive study was conducted comparing the blood pressure and heart rate responses to position change among hypovolemic and normovolemic subjects. A convenience sample of 32 men and women from an emergency room with complaints of diarrhea, vomiting, vaginal or rectal bleeding for $\ge$12 hours duration were recruited. The normovolemic group consisted of a convenience sample of 30 men and women from the community. Data analysis included a mixed design analysis of variance. Compared to supine baseline measurements, between group changes in the systolic, diastolic, and mean arterial blood pressure were not statistically significant (p $>$.05). Once the subject stood, heart rate increased statistically significant in both groups (p $<$.05). The data suggest orthostatic hypotension can be considered when the supine resting heart rate is $\ge$87 beats per minute, and if upon standing, heart rate increases by $\ge$19.33 or is $\ge$110 beats per minute. Heart rate measurements should be taken at one minute after standing.

In these experiments, we tested the hypothesis that sympathetic escape in skeletal muscle is mediated through a fall in parenchymal cell oxygen levels following blood flow reduction. This hypothesis predicts that if the fall in parenchymal cell PO₂ during stimulation can be minimized, escape should be reduced. To test this prediction, we studied the behavior of superficial arterioles of the cat sartorius muscle during 3 minutes of sympathetic nerve stimulation. The muscle was covered with silicone oil equilibrated with 0%, 5% and 10% oxygen. During stimulation under 0% oxygen, 90% of visible arterioles showed a significant secondary relaxation (escape). The relaxation averaged 55% of the initial constriction. Under 5% oxygen, resting arteriolar diameter was reduced by an average of 12% and escape was significantly reduced throughout the arteriolar network. Under 10% ambient oxygen, there was an additional 5% reduction in resting diameter and a further reduction of escape. Escape was not attenuated when control diameter was reduced to the same degree with arginine vasopressin, suggesting that the effect of oxygen was specific rather than secondary to an increase in vascular tone. The above observations are also consistent with the hypothesis that escape is mediated through a fall in vascular wall PO₂. To evaluate this possibility, periarteriolar and parenchymal tissue PO₂ were measured with oxygen microelectrodes during sympathetic stimulation under 0% and 10% oxygen suffusion of the muscle. In the proximal arterioles, the periarteriolar PO₂ during control and during stimulation was identical under 0% and 10% oxygen yet escape was reduced by 75% under 10% oxygen. Similarly, escape was reduced 90% in the distal arterioles under 10% oxygen but periarteriolar PO₂ was very nearly the same as that measured under 0% oxygen. In contrast, mean parenchymal tissue PO₂ fell to low levels during stimulation under 0% oxygen but did not fall below normal levels during stimulation under 10% oxygen. These findings argue against the hypothesis that a fall in vascular wall PO₂ is responsible for escape. The findings are consistent with the hypothesis that sympathetic escape in skeletal muscle is mediated through a fall in parenchymal cell PO₂. (Abstract shortened with permission of author.)

No description available.

Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the mesonephros and metanephros groups, respectively (P < 0.001). These data suggest an E7-E9 critical window of cardiovascular and renal development for atenolol. Acute atenolol exposure in E15 embryos showed an increase in mean arterial pressure with all but the highest dose. All doses significantly decreased heart rate.

Dissertation submitted to the Faculty of Health Sciences, University of Witwatersrand in fulfillment of the Master of Science in Medicine in the School of Physiology / Introduction: The changing socio-economic landscape in Africa has brought with it unique health challenges previously uncommon in people of African ancestry. Noncommunicable diseases such as coronary artery disease and stroke have emerged as pressing public health concern highlighting the need to find more on-target diagnostic tools as well as therapeutic interventions. Although ambulatory blood pressure (AMBP) has in many studies conducted in the western world proved to be an independent predictor of carotid intima-media thickness (C-IMT), such results cannot outright be imputed to people of African ancestry living in Africa. That is because people of African ancestry living in Africa are not only of a different ethnicity but are still in the early phases of an epidemiological transition while people in the western countries who are mostly Caucasians, are believed to be in the middle to late phases of an epidemiological transition. Methods: The relationship between the intima-media thickness of the common carotid artery (SonoCalcTM IMT version 3.4) and AMBP (Space labs model 90207) was determined in 320 randomly selected participants of African descent living in an urban developing community in South Africa. Relationships were determined after adjustment for (clinic blood pressure) BPc, age, gender, alcohol and tobacco use, the presence or absence of diabetes mellitus or inappropriate blood glucose control measured by glycated hemoglobin (ghb), antihypertensive therapy and menopausal status. III Results: Mean age for the study population was 43.7± 16.0 years. Both BPc and AMBP parameters were strongly associated with C-IMT (p<0.001) in univariate analysis. In multivariate analysis with BPc. and AMBP entered into separate models and after adjusting for cofounders, BPc. and AMBP maintained significant associations with CIMT. [BPc (partial r=0.0648, p< 0.1612), systolic blood pressure 24 (SBP24) (partial r= 0.236, p< 0.001), systolic blood pressure day (SBPd) (partial r= 0.302, p<0.05), systolic blood pressure night (SBPn) (partial r= 0.0983, p<0.05)]. When adjustments were made with BPc. and SBP24 entered into the same model, BPc lost its association with C-IMT, [SBP24 (partial r=0.236, p<0.001) SBPd (partial r=0.149, p<0.05), SBPn (partial r=0.172, p<0.05)]. Importantly the relationship between SBP24 and C-IMT persisted independent of body mass index (BMI), BPc and age. SBP24 had the highest significant association with C-IMT. Conclusion: SBP24 independently predicts C-IMT even in a model that includes conventional systolic blood pressure (SBPc) leading to the conclusion that AMBP is a more effective tool at diagnosing C-IMT alterations while BPcdoes not have an independent relationship C-IMT.

A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science, 2017 / Over the years, epidemiological research has seen differing levels of the prevalence of hypertension across socio-economic strata. However in Sub-Saharan Africa, the patterns of association and underlying risk factors have often been poorly understood. In this study, we examined the extent to which socio-economic factors affect systolic and diastolic blood pressure across gender. Furthermore we explored whether certain risk factors associated with hypertension mediate this relationship. We used data from the third phase of the National Income Dynamic Study conducted in South Africa in 2012 on more than 18,000 adult individuals. Structural equation modelling and multiple linear regression were used to estimate the relationship between blood pressure and various behavioural, demographic and socio-economic variables. These results were then compared to determine which technique provides more meaningful results. A higher socio-economic status was associated with a higher systolic and diastolic blood pressure in both males and females. Furthermore, body mass index was a mediator of the indirect effect of socio-economic status on blood pressure. Smoker status, alcohol consumption, physical exercise, emotional well-being and resting heart rate were also mediators; however their role was modest in comparison to BMI. One of the findings of this study is that a reduction in the BMI of an individual will have an impact on lowering hypertension. Furthermore, the promotion of healthy behaviours that target higher income groups need to be established so that these groups can make rational decisions in choosing their behaviours. / XL2018

Nos últimos 15 anos, o uso do propofol vem se popularizando na prática clínica como anestésico intravenoso para indução e manutenção da anestesia em cães e gatos. O objetivo deste estudo foi avaliar os efeitos do propofol na pressão arterial, freqüência e ritmo cardíacos, quando empregado na indução e na manutenção anestésica de cães, verificar a correlação entre os valores de freqüência cardíaca e pressão arterial média, obtidos durante a indução e a manutenção anestésica e avaliar a incidência de efeitos colaterais deste fármaco. Foram utilizados 53 cães, 15 machos e 38 fêmeas, clinicamente sadios, com idades entre 1 e 12 anos, peso entre 2 e 44 kg, de diferentes raças, categoria de risco ASA 1 ? 2. Após avaliação clinica, foi administrada a medicação pré-anestésica (T0) constituída de acepromazina (0,05mg/kg) e meperidina (3mg/kg) pela via intramuscular. A indução da anestesia foi realizada em dois momentos, no primeiro momento infundiu-se metade da dose de propofol calculada (T1), no segundo momento procedeu-se o término da administração da dose total de indução da anestesia (T2), o terceiro momento correspondeu a intubação orotraqueal (T3). Durante a manutenção da anestesia, avaliou-se os momentos após 5 minutos de manutenção (T4), 10 minutos (T5) e 20 minutos (T6), onde o grupo 1 recebeu o agente inalatório isofluorano em O2 a 100% e o grupo 2 infusão contínua de propofol na dose de 0,6mg/kg/min e O2 a 100%, ambos os grupos permanecendo em plano anestésico adequado. Pode-se observar que a freqüência cardíaca foi, em média, superior durante o período de indução anestésica e a pressão arterial média foi, em média inferior, porém, clinicamente, a magnitude destas alterações pode ser considerada de pouca importância clínica. Não existiu correlação estatisticamente significante entre a queda da pressão arterial média e o aumento da freqüência cardíaca em nenhum dos tempos analisados, o que leva a crer que o aumento da freqüência cardíaca se deve provavelmente à diminuição da atividade parassimpática neural cardíaca e prevalência da atividade simpática cardíaca, e a diminuição da pressão arterial encontrada pode ser secundária à diminuição da atividade simpática periferia. A avaliar o ritmo cardíaco notou-se diminuição da incidência de bradiarritmias e arritmia sinusal e um aumento do ritmo sinusal, provavelmente pela diminuição da atividade parassinpática cardíaca. Tais observações sustentam a hipótese de que o propofol pode agir diferentemente na atividade simpática periférica e cardíaca também nos cães. Pode-se ainda levantar a hipótese de que a atividade barorreflexa também pode estar diminuída nos cães já que não houve correlação significante entre a diminuição da pressão arterial e o aumento subseqüente da freqüência cardíaca. Durante a manutenção da anestesia houve uma queda da pressão arterial, sem importância clinica e não houve alteração significante em relação a freqüência cardíaca. Foi possível observar excitação em apenas dois animais no momento T1 e um animal em T2. Apnéia foi observada em apenas oito animais (15,1%) sete no momento T3. Outros trabalhos utilizando-se medidas da atividade barorreceptora, análise espectral da variabilidade da freqüência cardíaca, neuromicrografia ou até mesmo medida do clearence de norepinefrina para melhor avaliação da atividade simpática de cães durante a anestesia ainda devem ser realizados para comprovação destas hipóteses fortemente sugestivas pelos dados encontrados neste estudo. O propofol demonstrou ser um fármaco seguro quando empregado na indução e na manutenção da anestesia em cães, não causando alterações cardiovasculares clinicamente importantes. / In the last 15 years, using propofol has being popular in the practical clinic as intravenous anesthetic for induction and maintenance of the anesthesia in dogs and cats. The aim of this study was to evaluate the effect of propofol in arterial pressure, cardiac frequency and rhythm, when used in the induction and in the anesthetical maintenance of dogs, to verify the correlation between values of cardiac frequency and average arterial pressure, taken during the induction and the anesthetical maintenance and to evaluate the incidence of side effects of this drug. Had been used 53 dogs, 15 males and 38 females, clinically healthy, with ages between 1 and 12 years, weight between 2 and 44 kg, from different breeds, ASA classification 1 - 2. After clinical evaluation, the anesthetical drug was administered (T0) consisting of acepromazine (0,05mg/kg) and meperidine (3mg/kg) through intramuscular injection. The induction of the anesthesia was carried through at two moments: at the first moment was administered half of the dose of propofol calculated (T1), at second moment was proceeded the ending of the administration of the total dose of induction of the anesthesia (T2); the third moment corresponded the orotracheal intubation (T3). During the maintenance of the anesthesia, were evaluated the moments after 5 minutes of maintenance (T4), 10 minutes (T5) and 20 minutes (T6), when group 1 received isofluorane inhalatory agent in 100% O2 and group 2 continuous infusion of propofol in the dose of 0,6mg/kg/min and 100% O2, both groups remaining in adequate anaesthetic stage. It can be observed that the cardiac frequency was, in average, superior during anesthetical induction period and the average arterial pressure was often inferior, however, clinically the magnitude of these alterations can be considered of little clinical importance. Statiscally significant correlation did not exist between the fall of the average arterial pressure and the increase of the cardiac frequency in none of the analyzed periods, leading to believe that the increase of the cardiac frequency is must probably due to the reduction of the cardiac parasympathetic neural activity and prevalence of the cardiac sympathetic activity, and the reduction of arterial pressure can be secondary to the reduction of the periphery sympathetic activity. Evaluating the cardiac rhythm noticed reduction of the incidence of low cardiac frequency and sinusal arrhythmia and an increase of the sinusal rhythm, probably due to the reduction of the cardiac parasympathetic activity. Such comments support the hypothesis that propofol can act differently in the peripheral and cardiac sympathetic activity also in dogs. The hypothesis that pressure-induced activity could be also decreased in dogs can be raised, since there was not significant correlation between the reduction of arterial pressure and the subsequent increase of cardiac frequency. During the maintenance of the anesthesia there was a fall of the arterial pressure, of no clinical importance and there was no cardiac frequency significant change. It was possible to observe excitement in only two animals at moment T1 and one animal in T2. Apnea was observed in only eight animals (15.1%) seven at moment T3. Other studies using measurement of the pressure-induced activity, spectral analysis of the variability of cardiac frequency, neuromicrography or even though norepinephrine clearance measurement for better evaluation of the sympathetic activity of dogs during the anesthesia still must be done to prove these strong suggestive hypotheses for the data found in this study. Propofol demonstrated to be a safe drug when used in the induction and the maintenance of the anesthesia in dogs, not causing important cardiovascular clinical changes.