The role of coronary artery collaterals in the preservation of left ventricular function: a study to address a long-standing controversy.

INTRODUCTION: The functional significance of coronary artery collateral (CAC) vasculature in humans has been debated for decades and this has been compounded by the lack of a standard, systematic, objective method of grading and documenting CAC flow in man. CACs serve as alternative conduits for blood in obstructive coronary artery disease. This study aimed to evaluate the impact of CACs on left ventricular function in the presence of total coronary arterial occlusion. METHODS: The study group included the coronary angiographic records of 97 patients (mean age: 59 ± 8 years). CACs were graded from 0-3 based on the collateral connection between the donor and recipient arteries. Left ventricular function was computed from the ventriculogram and expressed as ejection fraction (EF). RESULTS: The mean EF of the patients with grades 0, 1, 2 and 3 CACs were calculated as 50.4, 47, 60.5 and 70%, respectively. A significant difference was recorded in the mean EF calculated for the different CAC grades (p = 0.001). There was a significant positive correlation (p < 0.001; r = 0.478) between the mean EF and the CAC grades. CONCLUSION: The patients with better coronary collateral grades had a higher mean EF. Therefore, as the grade of CACs increased, there was an improvement in their ability to preserve left ventricular function.

An anatomical investigation of the carotid canal.

BACKGROUND: The carotid canal (CC) located in the petrous temporal bone transmits the internal carotid artery, internal carotid venous plexus and sympathetic nerve plexus from the neck into the cranial cavity. It is an accessible passage into the cranial cavity and is considered an important anatomical landmark for neurosurgeons. The aim of this study was to investigate the topographical, morphometric and morphological parameters of the CC. MATERIALS AND METHODS: An examination of the CC and related adjacent structures in 81 dry skull specimens was performed. Distribution of sample by sex was 34 females and 47 males, and by race 77 African and 4 Caucasian. The mean age was 50 years (range: 14-100 years). RESULTS: The external opening of the CC was found to be round-shaped, oval-shaped and tear-drop-shaped in 28.4%, 49.4% and 22.2% of the specimens, respectively. (1) Mean diameters [mm]: (a) medio-lateral 7.52 mm and (b) antero-posterior 5.41mm. Statistically significant difference in the vertical diameter was recorded in the race groups and laterality of the samples. (2) Mean distances [mm] between: (a) medial margins of external opening of CC was 50.03 mm, (b) lateral margins of external opening of CC was 62.73 mm and (c) external openings of CC and foramen lacerum was 15.6 mm. There was a statistically significant correlation between race and location of the opening of external CC in relation to foramen lacerum (viz. postero-lateral, lateral and diagonal, and lateral). CONCLUSIONS: The present study corroborated previous reports on the CC; however, the tear-drop shaped external CC opening was a unique finding. The knowledge of the reference measurements pertaining to the CC and its relationship to adjacent structures may postulate a suitable surgical "safe-zone" range within the CC area.

Coronary artery dominance dependent collateral development in the human heart.

BACKGROUND: In obstructive coronary artery disease, coronary collateral arteries serve as alternative conduits for blood flow to the myocardial tissue supplied by the obstructed vessel(s). Therefore, they are a "natural coronary arterial bypass" to the region supplied by the obstructed vessels. This study aims to determine the influence of demographic and morphologic coronary arterial factors on coronary collateral development in coronary arterial obstruction. MATERIALS AND METHODS: The study group was selected from the coronary angiographic records of 2029 consecutive patients (mean age: 59 ± 12 years). Coronary collaterals were graded from 0 to 3 based on the collateral connection between the donor and recipient arteries. The angiograms of the patients (n = 286) with total obstruction of the coronary arteries were selected for analysis. RESULTS: There were no significant association between patients' age and sex and the formation of excellent collaterals. However, the location of atherosclerotic lesion affected collateral development in the right coronary artery. In addition, the right coronary arterial dominant pattern significantly influenced the formation of excellent coronary collaterals. CONCLUSIONS: Coronary collateral arteries are better developed in right dominant pattern. It may be concluded that coronary arterial morphological pattern influences coronary collateral artery development.

Anthropometry of the black adult tibia: a South African study / Antropometría de la tibia del negro adulto: un estudio sudafricano

The tibia is the medial long bone of the leg and is characterized by a shaft and two expanded extremities. Despite the recent advent of tibial bone graft harvesting, the tibia has also been confirmed to be of great forensic significance. As this appears to be the only tibial dry bone study done in Southern Africa, this study aimed to investigate morphological and morphometric parameters that are of clinical and anthropometric importance. Morphological and morphometric examination of 302 adult tibial bone specimens of Black South Africans obtained from the osteological bank of the Discipline of Clinical Anatomy at the University of KwaZulu-Natal was performed. The sample consisted of 168 males and 134 females with an age range of 15 to 87 years old. The number of nutrient foramina were: (a) One (male: 98.2%; female: 99.3%); (b) Double (male: 1.8%; female: 0.7%); Relationship of nutrient foramen to the soleal line: (a) infero-medial (male: 0.6%; female: 1.5%); (b) inferior but directly opposite the middle of the bone (male: 8.2%; female: 2.2%); (c) infero-lateral (male: 81.8%; female: 88.9%); (d) infero-lateral, along interrosseous crest (male: 4.1%; female: 3.0%); (e) supero-medial (male: 4.7%; female: 3.7%); (f) supero-medial, along interrosseous crest (male: 0.6%; female: 0%); (g) supero-lateral (male: 0%; female: 0.7%). Statistically significant differences were recorded in tibial morphometric parameters between males and females. The relationship between the number of nutrient foramina and the soleal line was of statistical significance (p= 0.002). The greater prevalence of a single foramen observed in this study compared favorably with that reported in previous literature. The recognition of the regional distribution of the nutrient foramina may prevent injury during tibial bone graft procedures. A thorough understanding of the tibial anatomy may also assist with the provision of demographic data required in forensic investigation.

La tibia es el hueso largo y medial de la pierna, con un eje y dos extremos expandidos. Además de ser considerado como posible donante de injerto, se ha confirmado su importancia en el ámbito forense. Este estudio tuvo como objetivo investigar los parámetros morfológicos, morfométricos y antropométricos de la tibia que son de importancia clínica. Se llevó a cabo un examen morfológico y morfométrico de 302 muestras de tibias perteneciente a negros sudafricanos adultos, obtenidas desde el banco osteológico del Departamento de Anatomía Clínica de la Universidad de KwaZulu-Natal. La muestra estuvo constituída por 168 hombres y 134 mujeres, con un rango etario entre 15 y 87 años. El número de forámenes nutricios fueron los siguientes: (a) Únicos (hombres: 98,2%; mujeres 99,3%); (b) Doble (hombres: 1,8%; mujeres: 0,7%). La relación del foramen nutricio con la línea del sóleo fue: (a) infero-medial (hombres: 0,6%; mujeres: 1,5%); (b) inferior y anterior a la mitad inferior del hueso (hombres: 8,2%; mujeres: 2,2%); (c) infero-lateral (hombres= 81,8%; mujeres= 88,9%); (d) infero-lateral, a lo largo del margen interóseo (hombres: 4,1%; mujeres: 3,0%); (e) supero-medial (hombres: 4,7%; mujeres: 3,7%); (f) supero-medial, a lo largo del margen interóseo (hombres: 0,6%; mujeres: 0%); (g) supero-lateral (hombres: 0%; mujeres: 0,7%). Estadísticamente, se registraron diferencias significativas en los parámetros morfométricos tibiales entre hombres y mujeres. La relación entre el número de forámenes nutricios y la línea del sóleo tuvo significación estadística (p= 0,002). La mayor prevalencia de un solo foramen nutricio observada en este estudio, se compara favorablemente con los casos reportados en la literatura analizada. El reconocimiento de la distribución regional de los forámenes nutricios puede evitar lesiones durante los procedimientos de injerto de hueso tibial. Un conocimiento profundo de la anatomía de la tibia también puede aportar datos demográficos necesarios para la investigación forense.

Absent left main coronary artery with variation in the origin of its branches in a South African population.

Coronary artery anomalies are traditionally classified into anomalies of origin, course and termination. One of the anomalies of origin is absence of the left main coronary artery (LMCA), where the left anterior descending (LAD), the circumflex (Cx) and the ramus medianus (RM) (when present) arteries originate directly from the left aortic sinus. The study aimed to document the prevalence of absent LMCA, discuss its possible embryogenesis and clinical relevance. A review of 407 coronary angiograms performed by cardiologists of three private hospitals in the eThekwini Municipality area of KwaZulu-Natal, South Africa, was performed. The LMCA was absent in 9.6% (39/407) of the coronary angiograms. The LAD and Cx arteries originated directly from the left aortic sinus with a single ostium in 8.6% (35/407) and separate ostia in 1% (4/407) of the angiograms. In four of the angiograms with absent LMCA, a RM artery was recorded originating directly from the left aortic sinus in addition to the LAD and the Cx arteries. Angiographic detection of the anomalies of the coronary arteries is essential in the determination of the significance of such findings and their management.

Determination of the median nerve safe-zone in the carpal tunnel using the distal forearm bony prominences.

BACKGROUND: The compression of the median nerve (MN) in the carpal tunnel (CT) is one of the most common aetiologies of entrapment neuropathy syndromes in clinical practice. The aim of this study was to investigate the relationship of the palpable bony prominences of the distal forearm (radial styloid process [RSP] and ulnar styloid process [USP]) with MN in the CT, in order to determine a safe-zone of the MN during carpal tunnel procedures. MATERIALS AND METHODS: This study involved the bilateral dissection of the CT region of 30 adult cadaveric specimens (n = 60). RESULTS: The mean distance between the RSP and USP was 49.34 mm. The mean distance of the MN from the RSP and the USP were 22.44 mm and 26.66 mm, respectively. The mean diameter of the MN within the CT deep to the flexor retinaculum was 5.93 mm. In addition, the MN was located postero-lateral and postero-medial to palmaris longus tendon (PLT) in 78.33% and 21.67% of specimens, respectively. CONCLUSIONS: This study found that the MN was located less than 60% of the RSP-USP distance from the RSP. Furthermore, the MN was mostly located postero-lateral to the PLT. Therefore, injection or surgical incision made at/medial to a point 60% of the RSP-USP distance from the RSP will be outside the safe-zone of the MN. The knowledge of this surface anatomical relationship of the MN may be useful during decompression for CT syndrome.

Arterial variations of the subclavian-axillary arterial tree: its association with the supply of the rotator cuff muscles / Variaciones arteriales del árbol arterial subclavio-axilar: su asociación con la irrigación del manguito de los rotadores

The subclavian-axillary arterial tree is responsible for the arterial supply to the rotator cuff muscles as well as other shoulder muscles. This study comprised the bilateral dissection of the shoulder and upper arm region in thirty-one adult and nineteen fetal cadaveric specimens. The variable origins and branching patterns of the axillary, subscapular, circumflex scapular, thoracodorsal, posterior circumflex humeral and suprascapular arteries identified in this study corroborated the findings of previous studies. In addition, unique variations that are unreported in the literature were also observed. The precise anatomy of the arterial distribution to the rotator cuff muscles is important to the surgeon and radiologist. It will aid proper interpretation of radiographic images and avoid injury to this area during surgical procedures.

El árbol arterial subclavio-axilar, es responsable del suministro arterial de los músculos correspondientes al manguito de los músculos rotadores, así como de otros músculos del hombro. Este estudio comprende la disección bilateral del hombro y la región superior del brazo en 31 cadáveres adultos y 19 fetos. Las variables y patrones del origen, ramificación de las arterias axilar, subescapular, circunfleja escapular, toracodorsal, circunfleja humeral posterior y supraescapular, identificados en este estudio, corroboran los hallazgos de estudios anteriores. Además, se observaron variaciones únicas no comunicadas previamente en la literatura. La anatomía precisa de la distribución arterial de los músculos del manguito de los músculos rotadores es importante para el cirujano y el radiólogo. Esta información constituirá una ayuda para la adecuada interpretación de imágenes radiológicas y para evitar lesiones en esta área durante los procedimientos quirúrgicos.

The intramyocardial left anterior descending artery: prevalence and surgical considerations in coronary artery bypass grafting.

BACKGROUND: Major coronary arteries usually have a subepicardial course and only dip into the myocardium near or at their termination. However, occasionally a segment of the epicardial artery may have an intramural course, and it is often referred to as a myocardial bridge. The left anterior descending (LAD) artery is the most commonly bridged vessel. Its prevalence has been evaluated at both autopsy and angiography. However, in the literature reviewed it is apparent that there are no reports of the prevalence of the intramyocardial LAD (IMLAD) artery in coronary artery bypass graft (CABG) series. OBJECTIVES: To document the prevalence of the IMLAD artery in a series of CABGs and to describe the surgical techniques used in these cases. METHODS: A retrospective analysis of 1349 surgical reports of consecutive CABGs performed over a period of 23 years was conducted. RESULTS: An IMLAD artery was present in 293 patients (21.7%). The prevalence was 20.2% (51/253) in females and 22.1% (242/1096) in males. The IMLAD arteries extended into the interventricular septum in 3.8% (11/293) of the patients. CONCLUSION: An intramyocardial course of the LAD artery is relatively common in patients undergoing CABG and poses a challenge in bypass grafting. Techniques are described to address this anatomical variation when it is encountered at surgery.

Arterial supply to the rotator cuff muscles / Suministro arterial de los músculos del manguito rotador

The arterial supply to the rotator cuff muscles is generally provided by the subscapular, circumflex scapular, posterior circumflex humeral and suprascapular arteries. This study involved the bilateral dissection of the scapulohumeral region of 31 adult and 19 fetal cadaveric specimens. The subscapularis muscle was supplied by the subscapular, suprascapular and circumflex scapular arteries. The supraspinatus and infraspinatus muscles were supplied by the suprascapular artery. The infraspinatus and teres minor muscles were found to be supplied by the circumflex scapular artery. In addition to the branches of these parent arteries, the rotator cuff muscles were found to be supplied by the dorsal scapular, lateral thoracic, thoracodorsal and posterior circumflex humeral arteries. The variations in the arterial supply to the rotator cuff muscles recorded in this study are unique and were not described in the literature reviewed. Due to the increased frequency of operative procedures in the scapulohumeral region, the knowledge of variations in the arterial supply to the rotator cuff muscles may be of practical importance to surgeons and radiologists.

El suministro arterial a los músculos del manguito rotador generalmente es proporcionado por las arterias subescapular, circunfleja escapular, circunfleja humeral posterior y supraescapular. Se realizó la disección bilateral de la región escapulo humeral de 31 especímenes cadavéricos adultos y 19 fetos. El músculo subescapular estaba irrigado por las arterias subescapular, supraescapular y circunfleja escapular. Por otra parte, la arteria supraescapular irrigaba a los músculos supra e infraespinoso. Observamos que los músculos infraespinoso y redondo menor fueron irrigados por la arteria circunfleja escapular. Además de las arterias de origen y sus ramas, observamos que los músculos del manguito rotador son irrigados por la arteria escapular dorsal y las arterias torácica lateral, toracodorsal y circunfleja humeral posterior. Las variaciones en la irrigación de los músculos del manguito rotador registrados en este estudio son únicos y no existe una descripción referente a ellos en la literatura revisada. Debido a la mayor frecuencia de los procedimientos quirúrgicos en la región escápulohumeral, el conocimiento de las variaciones de la irrigación de los músculos del manguito rotador puede ser de importancia práctica para cirujanos y radiólogos.

Anatomic parameters of the left coronary artery: an angiographic study in a south african population / Parámetros anatómicos de la arteria coronaria izquierda: estudio angiográfico en una población sudafricana

An understanding of the left coronary artery (LCA) anatomy is important for accurate diagnosis and therapeutic intervention in the management of coronary arterial diseases. This angiographic study aims to document the parameters of the LCA that may be of importance in the diagnosis and treatment of coronary artery diseases. An analysis of 151 coronary angiograms obtained from the cardiac catheterization laboratory in the eThekwini Municipality area of KwaZulu-Natal, South Africa was performed. The mean length and diameter of the LCA were 10.4+/-4.1 mm (range 2.8-23.9 mm) and 3.8+/-0.8 mm (range 2.1-6.5 mm), respectively. The mean angle of division between the two main branches was 86.2°+/-26.1° (range 27°-68.5°). There was a positive correlation between the length and the angle of division of the LCA, with the longest LCAs having the largest angle of division. The branching patterns of the LCA were 80.8 percent, 18.5 percent and 0.7 percent for bifurcation, trifurcation and quadrifurcation, respectively. Coronary arterial dominance was 81.5 percent, 15.2 percent, and 3.3 percent for right, left, and co-dominance, respectively. This study corroborated earlier findings that the longer the length, the wider the angle of LCA division. A wide angle of LCA division, the shape and disposition of the proximal tract of LCA branches may affect flow, interfere with proper deployment of stents or may predispose to earlier atherosclerotic lesions.

La comprensión anatómica de la arteria coronaria izquierda (ACI) es importante para el diagnóstico e intervención terapéutica en el tratamiento de enfermedades arteriales coronarias. Este estudio angiográfico tuvo como objetivo documentar los parámetros de la ACI que pueden ser de importancia en el diagnóstico y tratamiento de enfermedades de las arterias coronarias. Se realizó el análisis de 151 angiografías coronarias obtenidas del laboratorio de cateterización cardíaca en el área del Municipio eThekwini de KwaZulu-Natal, Sudáfrica. La longitud y diámetro promedio de la ACI fueron 10,4+/-4,1 mm (rango 2,8 a 23,9 mm) y 3,8+/-0,8 mm (rango de 2,1 hasta 6,5 mm), respectivamente. El ángulo medio de la división entre las dos ramas principales fue 86,2°+/-26,1° (rango 27°­168,5°). Hubo una correlación positiva entre la longitud y el ángulo de división de la ACI, donde las ACI más largas tuvieron un ángulo de división más grande. Los patrones de ramificación de la ACI fueron porcentualmente 80,8 por ciento, 18,5 por ciento y 0,7 por ciento para bifurcación, trifurcación y quadrifurcación, respectivamente. La dominancia arterial coronaria fue del 81,5 por ciento, 15,2 por ciento y 3,3 por ciento para la derecha, izquierda y en co-dominio, respectivamente. Este estudio corrobora hallazgos anteriores en que cuanto mayor sea la longitud, mayor será el ángulo de la división de ACI. Un amplio ángulo de la división de la ACI, la forma y la disposición del tracto proximal de las ramas de la ACI pueden afectar el flujo, interferir con el despliegue apropiado de los stents o predisponer a las lesiones ateroscleróticas tempranas.

Trigeminal cave and ganglion: an anatomical review / Cavo y ganglio trigeminal: una revisión anatómica

The trigeminal cave (TC) is a special channel of dura mater, which extends from the posterior cranial fossa into the posteromedial portion of the middle cranial fossa at the skull base. The TC contains the motor and sensory roots of the trigeminal nerve, the trigeminal ganglion (TG) as well as the trigeminal cistern. This study aimed to review the anatomy of the TC and TG and determine some parameters of the TC. The study comprised two subsets: A) Cadaveric dissection on 30 sagitally sectioned formalin fixed heads and B) Volume injection. We found the dura associated with TC arranged in three distinct layers. TC had relations with internal carotid artery, the cavernous sinus, the superior petrosal sinus, the apex of petrous temporal bone and the endosteal dura of middle cranial fossa. The mean volume of TC was 0.14 ml. The mean length and breadth of TG were 18.3 mm and 7.9 mm, respectively, mean width and height of trigeminal porus were 7.9 mm and 4.1 mm, respectively, and mean length of terminal branches from TG to point of exit within skull was variable. An understanding of the precise formation of the TC, TG, TN and their relations is important in order to perform successful surgical procedures and localized neural block in the region of the TC.

El cavo trigeminal (CT) de la duramadre es un conducto especial que se extiende desde la fosa craneal posterior a la parte posteromedial de la fosa craneal media en la base del cráneo. El CT contiene las raíces motoras y sensoriales del nervio trigémino (NT), ganglio trigeminal (GT), así como la cisterna trigeminal. Este estudio tuvo como objetivo examinar la anatomía del CT y GT y para determinar algunos parámetros del CT. El estudio se realizó en dos etapas: A) la disección anatómica de 30 cabezas seccionadas sagitalmente y B) la inyección para estimar volumen. Fueron encontrados tres capas distintas de duramadre asociadas al CT. El CT se relacionó con la arteria carótida interna, el seno cavernoso, el seno petroso superior, el vértice de la porción petrosa del hueso temporal y la dura endosteal de la fosa craneal media. El volumen medio del CT fue de 0,14 ml. La longitud media y la amplitud del GT fueron 18,3 mm y 7,9 mm, respectivamente. La media del ancho y alto del poro trigeminal fueron 7,9 mm y 4,1 mm, respectivamente; la longitud media de las ramas terminales del GT al salir del cráneo fue variable. El conocimiento preciso de la formación del CT, GT, NT y sus relaciones es necesario para realizar procedimientos quirúrgicos exitosos o el bloqueo nervioso localizado en la región del CT.

The impact of left main coronary artery morphology on the distribution of atherosclerotic lesions in its branches.

BACKGROUND: Atherosclerotic occlusion of a coronary vessel is the commonest cause of ischaemic heart disease. The distribution of atherosclerotic lesions is not random,with stenoses preferentially situated at branch ostia, bifurcation points, and the proximal segments of daughter vessels. The aim of this study was to determine the effect of the intrinsic anatomical properties of the left main coronary artery(LMCA) on the distribution of atherosclerotic lesions in its branches. MATERIALS AND METHODS: A retrospective review of 170 consecutive coronary angiograms obtained from the cardiac catheterisation laboratories of private hospitals in the eThekwini Municipality area of KwaZulu-Natal, South Africa was performed. The LMCA was absent in 19/170 (11.2%). The remaining angiograms(n = 151) were divided into two groups: normal 63/151 (41.7%) and those with coronary artery disease (CAD) 88/151 (58.3%). The CAD group was sub-divided into proximal 42/88 (47.7%), mixed (proximal and distal) 26/88 (29.6%) and distal20/88 (22.7%) sub-groups based on the location of atherosclerotic lesions in the branches of the LMCA. RESULTS AND CONCLUSIONS: The mean length, diameter and angle of division of the LMCA were as follows: Total angiograms: 10.4 mm, 3.8 mm and 86.2o; normal group:10.5 mm, 3.9 mm and 85.7o, CAD group: 10.2 mm, 3.7 mm and 86.3o; proximal sub-group: 10.9 mm, 3.7 mm and 91.6o, mixed sub-group - 9.8 mm, 3.7 mm and 85o and distal sub-group - 9.1 mm, 3.8 mm and 79.4o, respectively. The vessels with proximally located lesions were recorded to have longer lengths and wider angles of division than vessels with distal lesions. Coronary angiographic delineation of the LMCA anatomy may be predictive of a coronary arterial arrangement that may favour the progression of proximally located lesions.

The prevalence and clinical importance of an "additional" terminal branch of the left coronary artery.

The left coronary artery (LCA) usually divides into two (anterior interventricular artery [AIA] and left circumflex [LCx] artery) or less frequently into the AIA, LCx,and one or more "additional" terminal branch/es (ATBs). These ATBs of the LCA have no unanimity regarding their anatomical nomenclature. There is a lack of common consensus on the criteria used for their definition, and they are also absent from the current Terminologia Anatomica (1998). This study, therefore,aimed to document the prevalence of the ATBs of the LCA, discuss their clinical importance, and propose an anatomical nomenclature. This study was conducted by reviewing 367 coronary angiograms. The termination patterns of the LCA were classified into 3 categories based on the number of their branches, viz. (a) bifurcation78.2%, (b) trifurcation 20.4%, and (c) quadrifurcation 1.4%, respectively. The presence of an ATB was recorded in 21.8% of the angiograms. The identification of this vessel may be of clinical importance because the extent of its supply may decrease the effect of occlusion of the LCx artery and AIA on the myocardium.The term "left ramus medianus artery" is proposed as the nomenclature for the ATB of the LCA.

A comparison of the dielectric behaviour of human haemoglobin SC with SS and AA in solution.

Haemoglobin (Hb) SC is one of the most prevalent sickle-cell disorders. Patients with Hb SC are known to inherit a befa(S)-globin gene from one parent and a beta(C)-globin gene from the other. The radiofrequency dielectric properties of heterozygous Hb SC have been investigated and compared with those of homozygous Hb SS and AA in solution. The relative permittivity, epsilon', the dielectric loss factor, epsilon", and the energy dissipation factor, tan delta, of the different haemoglobin samples have been measured in the frequency range 0.1-50.0 MHz using a TF1245 Marconi Q-meter working in conjunction with a TF1246 oscillator at a room temperature of 26.0 +/- 0.5 degrees C. The Hb SC samples were found to exhibit dielectric dispersions distinctly different from those of Hb SS and AA. The dielectric data were fitted to the Cole-Cole structural equation and the fitted parameters are presented. The results are discussed on the basis of the molecular structure and polymerization characteristics of the haemoglobins in solution.

Dielectric characteristics of packed human erythrocytes with haemoglobins F, AA, AS and SS.

The radiofrequency dielectric behaviour of packed human erythrocytes has been investigated in normal haemoglobins F and AA and also abnormal haemoglobins homozygous SS and heterozygous AS. Dielectric measurements were made in tightly packed blood cells at an average room temperature of 26.5 +/- 0.5 degrees C in the frequency range from 0.1 to 100 MHz. In agreement with previous findings in many biological molecules, all the packed erythrocytes of the different haemoglobins exhibited a decrease in dielectric constant and an increase in conductivity with frequency. However, each type has been found to show distinct dielectric dispersion with respect to the others and this has been associated with their molecular structure in addition to the polarization of cell membrane. The possible application of this technique in identifying different haemoglobins of the blood has been suggested.