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Biomedical subjects

C Fuchs

Publications and source records attributed to C Fuchs.

At least 145 records · Page 8Linked to original sources

On the distribution of the nucleotides in seven completely sequenced DNAs.

Several Markov chain models (up to fourth order) have been fitted to the sequences of the seven DNAs presented in Fuchs et al. (1980). Two methods for determining the order of Markov chain are applied to the data. The two methods lead to different conclusions and we discuss these discrepancies. When the distribution of the nucleotides in a DNA sequence is investigated, it is suggested that the study on the order of the Markov model should be supplemented with additional analysis.

Bacteriophage phi X 174↗

Pediatric care for exceptional children: an inferential procedure utilizing consumer satisfaction information.

Medical services provided to 402 children with exceptional health and educational needs between 1975 and 1978 were systematically studied to determine consumer satisfaction. Legislation (PL 94-142) has made it mandatory for complete services to be provided to exceptional children from birth to age 21. Although the major responsibility to provide these services lies with local public schools, physicians often are involved and can help to provide optimum care to these children. This report describes a medical-educational system that delivers multispecialty pediatric services. An inferential evaluation procedure has been applied to this system that shows how consumer input can lead to improved medical services. Statistical procedures used to examined the data include analysis of variance, utilized in comparing the satisfaction ratings over time, and multiple linear regression analysis, to predict medical service activities of importance to consumers.

Analysis of Variance↗

The action of 1,25 (OH)2D3 on turnover kinetic, remodelling surfaces and structure of trabecular bone in chronic renal failure.

Fibroosteoclasia as well as osteoidosis are reduced by 1,25(OH)2D3 treatment if secondary hyperparathyroidism preexists. Fibrosteoclasia completely disappeared after 6 months therapy in some cases. 1,25(OH)2D3 has no or only a very slight effect on the disturbed mineralization in type II of renal bone disorder (osteoidosis only, no signs of secondary hyperparathyroidism). The appositional rate of the osteoblasts increases under 1,25(OH)2D3 treatment if serum PTH values are raised. 1,25(OH)2D3 seemed to have, in the chosen dosage of this study, a self-limiting effect by reducing the bone-forming cells, i.e. the osteoblasts. This state already represents an overtreatment of the underlying bone disease.

Adult↗

[Bioavailability of monofluoride preparations for dental caries prophylaxis (author's transl)].

Three different preparations containing 1 mg fluoride were given to 12 volunteers: preparation A, 1 hydrous solution, = 1 mg F-/100 ml, preparation B = 2 tablets at 0.5 mg F- and preparation C = 1NaF tablet with 1 mg F-. Representactive kinetic data could be obtained by means of restricted fluoride in the diet, a reproducible method yielding minimum detectable fluoride concentration and selection of suitable volunteers.. The enteral absorption of fluoride from solution A was more rapid (half-life of invasion = 20.2 min and 16.9 min, respectively). The delayed release is a consequence of the galenic mixture. In addition, the maximum concentration in plasma was greater and was reached sooner in preparation A when compared to the other preparations. In contrast, there was no difference in the areas under the curves, indicating that the relative bioavailability of fluoride is the same in all preparations.

Adult↗

Biochemical investigations of CAPD: plasma levels of trace elements and amino acids and impaired glucose tolerance during the course of treatment.

Investigations have been initiated into the effect of CAPD on the plasma concentrations of trace elements and amino acids, and in particular the response of patients to an oral glucose tolerance test (OGTT) during the course of treatment. Six months CAPD had no effect on the plasma concentrations of aluminium, fluoride, zinc and copper. Levels of aluminium and fluoride were above the normal range. Loss of amino acids in the dialysate correlated with their plasma concentrations. No changes were observed in the E/NE, Val/Gly or Tyr/Phe ratios during nine months treatment. Five CAPD patients demonstrated an impaired glucose tolerance in response to an OGTT after one month of treatment and a further deterioration occurred in the glucose tolerance of three patients after another six months CAPD. In a preliminary investigation with fructose substituted for glucose in the dialysate of one patient, an improvement in the OGTT and rate of insulin secretion was observed after 3 days dialysis against fructose.

Adolescent↗

Functional aspects of the superoxide dismutative action of Cu-penicillamine.

The superoxide dismutative action of Cu-penicillamine was examined by pulse radiolysis. The second order rate constand of the reaction wpith superoxide was 0.4 +/- o.2.10(9) M-1.s-1, comparable to the action of Fe and Mn-superoxide dismutases. No marked pH-dependence was seen. Neither ethylene diamine tetraacetic acid nor cyanide affected the catalytic action of Cu-penicillamine. The cyanide resistant reactivity as well as further X-ray photoelectron spectrometric measurements supported the suggestion of a Cu(I) stabilized sulphur radical being the active species involved in the catalysis of superoxide dismutation.

Binding Sites↗

[Hyperparathyroidism and metabolic acidosis (author's transl)].

Severe secondary hyperparathyroidism and marked metabolic acidosis occurred in five patients in advanced renal failure due to chronic interstitial nephritis. In all instances there was an immediate and lasting rise in plasma standard bicarbonate concentration after subtotal parathyroidectomy. These observations suggest that the metabolic acidosis in some patients with advanced renal failure is, at least in part, due to hyperparathyroidism and, therefore, responsive to its appropriate treatment.

Acidosis↗

[Influence of dental caries prophylaxis using fluor-vigantoletten 1000 on plasma fluoride levels in infants (author's transl)].

A group of 57 newborns was divided into two: group I (27 subjects) received solely 1,000 I.U. vitamin D3 per day for 6 months, whereas group II (30 subjects) were given a combination of 1,000 I.U. vitamin D3 and 0.25 mg fluoride. At the end of the time of observation there was a significant difference between the plasma concentrations in the two groups. The median value was 13.06 microgram/l (range: 8:18-39.4 microgram/l) in group I and 16.54 microgram/l (range: 9.9--41.2 microgram/l) in group II. Fluoride is obviously available to infants when administered in combination with Vitamin D3. In addition, it could be proven, that after 6 month administration of fluoride there are no signs of cumulation, overdosage or even intoxication.

Cholecalciferol↗

[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↗

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↗

[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↗

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↗

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↗

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↗

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↗