The biochemical composition of body fluids, their osmolalities and ultrafiltrates

Chughtai, M. A (1966) The biochemical composition of body fluids, their osmolalities and ultrafiltrates. PhD thesis, University of Glasgow.

Abstract

The serum osmolality has been determined in 101 cases of hypochloraemia. The cause of the chloride depletion was duo to vomiting, less often to continuous gastric suction, and rarely to diarrhoea or fistulae, associated with various clinical disorders. Patients were divided into three groups according to whether the serum osmolality was normal, decreased or increased. The patients in group I succeeded in maintaining the osmotic pressure within normal limits in spite of chloride depletion by the compensatory retention of bicarbonate and urea. This compensatory mechanism failed to operate in the group II patients where the loss of chloride eventually resulted in lowering the osmotic pressure. In group III patients, the serum osmolality was elevated in spite of low chloride, partly due to bicarbonate retention but mainly due to urea retention. There was a relationship between the increased serum osmolslity and urea concentration. Although the chloride ions contribute 35% of the total osmotic pressure, there was no relationship between the serum chloride concentration and the osmotic pressure in any of the three groups. The patients in group III may simply be the extension of group I cases. The transition of one group to the other probably coincides with the onset of renal dysfunction. This kidney involvement is a reversible process and, therefore, must be distinguished from renal disease. The patients in group II were quite distinct from the oases in the other two groups and wore not in the early stages of biochemical upset, end had not passed through the stages corresponding to other groups. Failure to retain urea and to maintain the osmotic pressure of extracellular fluids may be due to a defect in come mechanism presumably related to osmoregulatory centres, abnormal secretion of antidiuretic hormone or to renal tubular damage. PART 2. A new simple ultrafiltration technique has been described and the procedure outlined for ultrafiltration of blood serum. The importance of the method of sample collection, duration of ultrafiltration and pH was investigated. The ultrafiltration results were affected considerably by large changes in pH, while duration of ultrafiltration had no effect. For 20 healthy human subjects, the range for ultrafilterable celcium was found to be 55-61% of the total serum calcium. Ultrafiltration data on sera from patients with hyperparathyroidism before and after removal of parathyroid adenomas, hypoparathyroidism, vitamin D therapy, multiple myeloma, hyperealcaemia due to other causes, and renal disease has been presented. The serum ultrafilterable calcium was raised before operation in ever patient with a functioning parathyroid adenoma even though the serum total calcium was within the normal limits. After removal of the adenema, the serum ultrafilterable celcium always fell below normal. This fall was proportionately greater then the fall in the protein hound fraction. It was inferred that parathyroid hormone reduces the capacity of serum protein to hind calcium. This was supported by the observation of the effect of intravenous calcium on a human subject where the suppression of parathyroid glande resulted in an increase in the binding capacity. The ultrafilterable calcium was reduced in oases of hypercalcaemia due to causes other then hyperparathyroidium. This was also associated with reduced ultrafiltorability of inorgenic phosphate, possibly due to the formation of non-filterable calcium-phosphate-protein complex. Hence difficult cases such as these with functioning parathyroid adenoma associated with normal serum calcium values end cases with hypercalcaemia without parathyroid adenoma, the ultrafiltration results may be of some aid in the differiential diagnosis. The serum ultrafilterable calcium was found to be diminished in hypoparathyroidism, but poor correlation of the extent of tetany with either total serum calcium or the ultrafiltorable calcium was found to exist. Hypoprotenaemia was generally associated with hypocalcaemia, which was accompanied by normal or, more frequently, a high percentage ultrafiltorability of calcium. The hypoosicaemia present was due to the loss in the hound fraction. In renal disease although the total serum calcium was low the percentage of ultrafilterable calcium was almost invariably high, regardless of the concentration of serum proteins. The absence of tetany in those cases was not duo to acidosis alone. Other factors e.g. hypoalbuminaemia and the specific alteration in binding capacity of serum protein by the excess secretion of parathyroid hormone also contribute in maintaining the ultrafilterable calcium. Normal values for both serum and ultrefiltarable magnesium were found in hyperparathyroidism and in hypoparathyroidism. It was concluded that parathyroid glands play no part in magnesium metabolism.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: E B Hendry
• Keywords: Medicine
• Date of Award: 1966
• Depositing User: Enlighten Team
• Unique ID: glathesis:1966-72616
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 11 Jun 2019 11:06
• URI: https://theses.gla.ac.uk/id/eprint/72616