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Biomedical subjects

C Fuchs

Publications and source records attributed to C Fuchs.

At least 55 records · Page 3Linked to original sources
PubMed1979

[Comparison of ion-selective electrodes and flame photometry for the determination of serum Na+ and K+ for clinical purposes (author's transl)].

The ORION SPACE-STAT (SS-30) and the TECHNICON STAT/ION were used to investigate quality control of Na+- and K+-determinations in test sera (n=8) and in the plasma of 100 patients. The flame photometer IL 543 was used as a reference apparatus. The ion-selective electrode instruments, SS-30 and STAT/ION, gave results very similar to those of flame photometry. The values from the SS-30 were higher by an average of 3% to 5% compared with the values from the other instruments. An explanation for this bias may be the fact that the SS-30 (unlike the STAT/ION and the IL 543) measures electrolyte activities or concentrations in undiluted plasma water. On the basis of these results the routine use of ion-selective electrodes for Na+- and K+-determination can be recommended for clinical laboratories.

Electrodes↗
PubMed1979

Capabilities of the Redy cartridge for regeneration of hemofiltrate.

Capabilities of the Redy cartridge for hemofiltrate regeneration were tested. Electrolytes, creatinine, BUN, uric acid, acid-base, glucose, heparin, fluoride and amino acids were measured in the cartridge inflow and outflow (V = 70 ml/min) over a four-hour period. There was complete adsorption of potassium, calcium, magnesium, creatinine, BUN, uric acid, phosphate and heparin. Sodium ions, hydrogen ions, fluoride ions and possibly other trace elements are released by the cartridge. Amino acid absorption is almost complete if the amino acids are aromatic, have two or more N-atoms or if they have S-atoms. When using hemofiltrate after sorbent regeneration for reinfusion to the patient, one has to consider electrolyte substitution (i.e., K, Ca, Mg), sodium balance, trace element metabolism, acid-base problems, amino-acid profiles and ammonia overload.

Adsorption↗
PubMed1978

[Calcium and phosphate metabolism in hemofiltration (author's transl)].

In 10 patients undergoing hemofiltration treatment acute changes of parameters in the calcium-phosphate metaboism were investigated. Balance studies were also performed in all patients. Control studies were conducted after a 3-month interval in 7 patients. Whereas ionized calcium and 25-HCC remained constant, there was a significant decrease in phosphate, magnesium, fluoride and parathyroid hormone. Corresponding to these results, negative balances could be seen during the course of a hemofiltration treatment: for phosphate a mean value of -593 mg, for magnesium -8.4 mEq and for fluoride -458 microgram. When a calcium content of 3.75 mEq/l was used in the substitution solution, an only slightly positive calcium balance of +1.51 mEq/l (mean value) was found. A significant correlation between calcium and fluid balance was demonstrated by means of 197 filtration treatments of one patient: the calcium balance became negative whenever the fluid loss was greater than 3.86 liters. After a 3-month period no significant changes in the above parameters were found, which indicates, that disturbances in the calcium-phosphate-parathyroid hormone metabolism do not only lie in a reduced renal elimination. Even though our results do not indicate that hemofiltration treatment induces or increases the chances of renal osteodystrophy, the calcium concentration of the substitution solution should be increased to 4.0 mEq/l, in order to guarentee a positive calcium balance even by forced filtration.

Adolescent↗
PubMed1978

Determination of blood ionized calcium in a large segment of the normal adult population.

In two different laboratories ionized calcium was determined by use of a calcium selective electrode system of recent design in specimens of whole blood drawn from a total of 100 volunteers. Identical mean values were obtained in each laboratory. A small standard deviation was found supporting the view that [Ca2+] is normally maintained within a narrow range. Ancillary factors in [Ca2+] determination were evaluated, including effects of in-vivo produced changes in pH, and effects of addition of small amounts of heparin to the whole blood sample. A veno-arterial difference in [Ca2+] was insignificant.

Adolescent↗
PubMed1978

A simple method for identifying the palindromic sequences recognized by restriction endonucleases: the nucleotide sequence of the AvaII site.

Tables specifying the frequencies, distances between and positions of all possible tetra-, penta- and hexanucleotide palindromes in phiX174 and SV40 viral DNAs were prepared by a computer search of their base sequences. A simple method based on these tables is described for identifying the sequence recognized by any specific restriction endonuclease. The method requires experimental determination of the number and approximate sizes of the fragments obtained by digestion of phiX174 RF and SV40 DNAs. Using this method we identified the sequence for AvaII restriction endonuclease as 5'-GG(AT)CC.

Base Sequence↗
PubMed1978

Assessment of hormone loss through hemofiltration.

The concentrations of testosterone, cortisone, gastrin, insulin, gastric inhibitory polypeptide (GIP), somatomedin B, parathyroid hormone (PTH), human growth hormone (HGH) and thyroid stimulating hormone (TSH) have been determined in the plasma and the ultrafiltrate of five uremic patients undergoing intermittent hemofiltration treatment. There was a considerable loss of gastrin, insulin, GIP, somatomedin B and PTH by hemofiltration treatment. The plasma concentrations, however, did not decrease except for immunoreactive-PTH (IR-PTH) which returned from elevated to normal levels. Cortisone, HGH and TSH concentrations in the ultrafiltrate were below the measureable range. A significant elimination of 11-hydroxylated androstans by hemofiltration may have a positive effect on the disturbed steroid metabolism. Results indicate that hemofiltration does not cause a hormone deficiency syndrome. On the contrary, the loss of degradation products of hormones with disturbing biological activity may be a favorable effect of the hemofiltration treatment.

Cortisone↗
PubMed1978

Clinical experience with continuously monitored fluid balance in automatic hemofiltration.

Automatic fluid balancing, as obtained with the hemofiltration machines from Sartorius (Göttingen, West Germany) and Dialysetechnik (Karlsruhe, West Germany), is accurate enough to replace bed scales, which have been necessary in conventional hemodialysis for patients who are confined to beds. Side effects such as hypotension, nausea and muscle cramps during treatment may be reduced with these new machines, compared to conventional methods, provided that the rate of effective fluid withdrawal does not exceed 0.5 L/hr. In particular, the constant weight loss associated with automatic hemofiltration seems to be well tolerated by the patients with fewer side effects.

Body Weight↗
PubMed1977

[Biological availability of fluoride after combined administration with vitamin D3 in man (author's transl)].

Six adults ingested 1 mg fluoride, first as NaF in a watery solution and, secondly, in tablet form (D-Fluoretten 1000). Fluoride concentration was almost identical in the two series. After initial values within the normal range concentrations rapidly rose to a maximum (six times normal) reached on average after 30 minutes, followed by an, at first steep then more gradual, fall in concentration over eight hours. The area under the curve was similar in the two series. These results indicate that the biological availability of fluoride is not influenced by vitamin D3 in the adult and, presumably, in the small child as well.

Adult↗
PubMed1977

[Hyperreninism without hyperaldosteronism in diuretic abuse: a report of a case with identification of mefruside and ethacrynic acid in urine (author's transl)].

A 46-year-old nurse had been hospitalized 16 times during the preceding five years because of episodes of excessive hypokalaemia. On admission to hospital there was hypokalaemia, polyuria, excessive plasma renin activity but no increased aldosterone secretion rate. Diuretic abuse was confirmed by gas-chromatography and mass spectrometry of mefruside and ethacrynic acid in the patient's urine. Apart from other interesting aspects of this case there was the demonstration of hyperreninism without hyperaldo-steronism. The stimulating effect of renin on aldosterone secretion was obviously lower than the inhibiting effect of hypokalaemia. The general term "renin-angiotensin-aldosterone system" is, therefore, misleading because it mentions only one pathway of aldosterone regulation. The combination of hypokalaemia, polyuria, hyperreninism without hyperaldosteronism is apparently the principal but not widely recognised feature of diuretic abuse.

Aldosterone↗
PubMed1977

[Histomorphometric study of pelvic-crest biopsies during long-term fluoride treatment of osteoporosis (author's transl)].

In 14 patients being treated with fluoride preparations for osteoporosis histomorphometric analysis of iliac biopsies showed that the volume of the mineralised spongiosa had increased by more than 20% above initial level in eight instances. The volume of the osteoid in ten cases had also increased, generally most markedly in the first year. In some cases the clinical symptoms corresponded to the histomorphometric findings. The results suggest that fluoride treatment of osteoporosis can be continued beyond one year. But this should only be done under precise control also of histological bone studies because in three of the patients the spongiosa volume had reached high normal values already after one to three years of treatment.

Adolescent↗
PubMed1977

[Surgical aspects of secondary hyperparathyroidism (author's transl)].

During long-term dialysis of patients in chronic renal failure disorders of mineral metabolism in the sense of renal osteodystrophy occur increasingly with time. Quite separate from these patients with renal osteopathy (osteomalacia and osteopenia) as a result of dialysis there is a group of patients in whom, despite appropriate dialysate composition, a full-blown picture of renal osteodystrophy due to secondary hyperparathyroidism develops. Subtotal parathyroidectomy will significantly improve them. Experience in 12 patients has demonstrated that, in addition to the clinical signs, biochemical findings and radiological changes, the quantitative evaluation of iliac crest biopsy and determination of parathormone and ionised serum-calcium fraction are decisive as indications for surgery. In these patients subtotal parathyroidectomy gave satisfactory results, but the treatment of renal osteopathy in the sense of osteopenia is often unsatisfactory and the full clinical picture can often be improved only by early renal transplantation.

Adult↗
PubMed1977

Effect of dialysate calcium concentration on plasma parathyroid hormone during hemodialysis.

The effect of changes in the dialysate calcium concentration on calcium fractions and parathyroid hormone species in plasma during hemodialysis has been examined. C-terminal immunoreactive parathyroid hormone was suppressed when plasma calcium increased by greater than 25% whereas N-terminal fragments demonstrated an increase. The significance of this is discussed in light of present knowledge of parathyroid hormone metabolism.

Adult↗
PubMed1977

Parathyroid hormone, calcium and phosphate balance in hemofiltration.

The acute changes in calcium, phosphate and parathyroid hormone have been examined in chronic renal failure patients under-going hemofiltration therapy and the results compared to a similar group treated by hemodialysis. In both groups there was a significant increase in Catot (0.32 mEq/1 for hemodialysis; 0.56 m Eq/1 for hemofiltration) with Ca++ remaining constant. Plasma phosphate and parathyroid hormone decreased during hemofiltration. Calcium balances were slightly positive and phosphate balances distinctly negative in all cases. To date there is no indication of induced osteodystrophy during hemofiltration therapy, although long-term studies are needed. However, the present results indicate, that hemofiltration more closely approaches the physiological situation than conventional hemodialysis.

Calcium↗