Plasma and cerebrospinal fluid magnesium, calcium and potassium concentrations in dairy cows with hypomagnesaemic tetany

Jv, Pauli; Tf, Allsop

doi:10.1080/00480169.1974.34175

Cited by 13 publications

(13 citation statements)

References 1 publication

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“…However, the postmortem diagnosis of tetany in ruminants is very difficult. Samples of CSF can be useful but they need to be taken within 12 hours of death and must be uncontaminated with blood (Pauli and Allsop 1974); in practice it is difficult to meet these criteria. Serum magnesium concentrations are unreliable because of the rapid leakage of magnesium from surrounding tissues (Smith and Edwards 1988).…”

mentioning

confidence: 99%

Postmortem biochemical markers of experimentally induced hypomagnesaemic tetany in sheep

McCoy¹,

Bingham²,

Hudson³

et al. 2001

Veterinary Record

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Hypomagnesaemic tetany was induced in non-lactating and lactating ewes by feeding them semi-synthetic low magnesium diets containing additional potassium chloride and citric acid. Aqueous and vitreous humour were sampled from one eye at the time of death (fresh) and from the second eye after the head had been stored at ambient temperature for 24 hours (24.hour). There were significant relationships between the concentrations of magnesium in cerebrospinal fluid and plasma and its concentrations in fresh aqueous humour and fresh vitreous humour. Magnesium concentrations of <0.33 mmol/litre in fresh aqueous humour and <0.50 mmol/litre in 24.hour aqueous humour were associated with severe hypomagnesaemia and tetany. However, the concentration of magnesium in aqueous humour is relatively unstable and, unless the time of death was known accurately, its interpretation would be difficult. Magnesium concentrations of <0.60 mmol/litre in fresh vitreous humour and <0.65 mmol/litre in 24-hour vitreous humour were associated with severe hypomagnesaemia and tetany in adult sheep. The concentration of magnesium in vitreous humour was relatively stable for up to 48 hours postmortem.

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mentioning

confidence: 99%

Postmortem biochemical markers of experimentally induced hypomagnesaemic tetany in sheep

McCoy¹,

Bingham²,

Hudson³

et al. 2001

Veterinary Record

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“…Experimental hyperkalaemia has been shown to decrease the CSF magnesium concentrations of ventriculocisternally perfused sheep (Parkinson and Leaver 1980). However, the role of blood potassium concentrations in clinical grass tetany is not clear and observations suggest that they begin to increase only after the onset of tetany (Pauli and Allsop 1974). Possibly high circulating potassium concentrations, by inhibiting magnesium transfer into the CSF, exacerbate the tetany or delay recovery following magnesium treatment.…”

Section: Discussionmentioning

confidence: 97%

“…Clinical signs of tetany in sheep have also been produced by perfusion of the CSF space with an artificial CSF solution low in magnesium (Allsop and Pauli 1975). However, instances of grazing cattle with severe hypomagnesaemia but normal concentrations of magnesium in lumbar CSF, and no tetany (Pauli and Allsop 1974) may indicate that factors other than the magnesium concentration of blood affect the transport of magnesium into the CSF. Parkinson and Leaver (1980) demonstrated that experimental hyperkalaemia lowered the concentration of magnesium in sheep CSF.…”

Section: Introductionmentioning

confidence: 99%

“…However, protracted and severe hypomagnesaemia will cause a decrease in the concentration of magnesium in the CSF of both sheep (Meyer and Scholz 1972) and cattle (Pauli and Allsop 1974). An examination of the relationship between concentrations of magnesium in blood and ventricular CSF in cattle (Allsop and Pauli 1985) indicated that once the blood magnesium concentration had fallen below O· 5 mmoll-1 the magnesium concentration of the CSF began to decline until, after various periods of time, it had fallen to about O· 5 mmol m -1 when tetany supervened.…”

Section: Introductionmentioning

confidence: 99%

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Transfer of Magnesium across the Perfused Choroid Plexus of Sheep

Tf¹

1986

Aust. Jnl. Of Bio. Sci.

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Isolated perfused choroid plexus preparations from sheep were used to study the effects of low concentrations of magnesium in the perfusion fluid on the transfer of magnesium into choroid plexus fluid (CPF). A perfusion fluid of similar electrolyte composition to sheep blood resulted in CPF similar to ventricular cerebrospinal fluid at a rate of 2·2 III min -1 mg -I dry choroidal tissue. Decreasing the concentration of magnesium in the perfusion fluid caused a fall in the concentration of magnesium in the CPF, although it remained higher than in the perfusion fluid. The rate of transfer of magnesium from the perfusion fluid to the CPF decreased in the presence of high levels of potassium in the perfusion fluid. But decreasing the concentration of calcium in the perfusion fluid had no effect on magnesium transfer rates.These results suggest that the ability of the choroid plexus to transport magnesium against a concentration gradient is an important control of the concentration of the cerebrospinal fluid. However, this ability is insufficient to maintain cerebrospinal fluid concentrations of magnesium at normal levels when the blood magnesium concentration is below about 0'5 mmoll-I .Extra keyword: hypomagnesaemia.

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“…The signs of tetany in severely hypomagnesae mic sheep and dairy cows are associated with low CSF magnesium concentrations (Meyer and Scholz 1972;Pauli and Allsop 1974). Verstraeten (1950) and Leusen (1950) perfused anaesthetized dogs ventriculociste rnally for 15 min with a synthetic CSF containing no magnesium and could find no consistent effect on the respiration rate, cardiac output or blood pressure.…”

Section: Introductionmentioning

confidence: 99%

Responses to the Lowering of Magnesium and Calcium Concentrations in the Cerebrospinal Fluid of Unanaesthetized Sheep

Allsop¹,

Pauli²

1975

Aust. Jnl. Of Bio. Sci.

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A technique for ventriculolumba r perfusion of the cerebrospinal fluid space has been used to study the neuromuscular effects of low concentrations of magnesium and calcium in the cerebrospinal fluid of conscious sheep. Perfusion with synthetic cerebrospinal fluid solutions containing less than O' 6 mg magnesium/lOO ml produced episodes of tetany which were abolished by perfusion with a solution of normal magnesium concentration. This suggests that the low cerebrospinal fluid magnesium concentrations reported in cases of hypomagneseam ic tetany may result in changes within the central nervous system that could produce the nervous signs. Perfusates with a calcium concentration below 2·0 mg/lOO rnl caused hyperpnoea and continuous muscle tremors. Magnesium (0' 6 mg/lOO m!) and calcium (2·0 mg/lOO ml) perfused simultaneously acted synergistically to produce signs characteristic of low levels of each of the ions.

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Plasma and cerebrospinal fluid magnesium, calcium and potassium concentrations in dairy cows with hypomagnesaemic tetany

Cited by 13 publications

References 1 publication

Postmortem biochemical markers of experimentally induced hypomagnesaemic tetany in sheep

Postmortem biochemical markers of experimentally induced hypomagnesaemic tetany in sheep

Transfer of Magnesium across the Perfused Choroid Plexus of Sheep

Responses to the Lowering of Magnesium and Calcium Concentrations in the Cerebrospinal Fluid of Unanaesthetized Sheep

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