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Biomedical subjects

C Fuchs

Publications and source records attributed to C Fuchs.

At least 127 records · Page 7Linked to original sources

Effect of omega-3 fatty acids on growth of a rat mammary tumor.

The effect of administering marine oil that was rich in omega-3 fatty acids on tumor growth was studied in female inbred F344 rats that received transplants of R3230AC mammary adenocarcinoma. Four groups of rats were maintained on a normal rat chow diet containing 5% fat, and marine oil supplementation was started 1 week prior to transplantation of the tumors. The marine oil provided 17, 33, and 67 mg of 5, 8, 11, 14, 17-eicosapentaenoic acid (EPA) and 16, 32, and 64 mg 4, 7, 10, 13, 16, 19-docosahexaenoic acid (DHA) a day. A significant reduction in weight (g) and volume (cm3) of the rat R3230AC mammary tumor was observed after 4 weeks of treatment. EPA (20:5 omega-3) and DHA (22:6 omega-3) were found in choline phospholipid fractions of mammary tumors from rats given marine oil. Both tumor content and synthesis in vitro of prostaglandins of two series were inhibited in the marine oil-treated groups. These data indicated that the mechanism underlying inhibition of mammary tumorigenesis may be linked, in part, to the inhibitory effect of both EPA and DHA on arachidonic acid metabolism.

Adenocarcinoma↗

Prevalence of mandibular dysfunction in 10-18 year old Israeli schoolchildren.

The prevalence of mandibular dysfunction in a sample of 369 Israeli schoolchildren was found to be 56.4%, indicating that one or more of the cardinal symptoms were present. It increased with age from about 51% in the 10-13 year old group to 67.8% in the 16-18 year olds. The most common cardinal sign of dysfunction was joint sounds (35.8%), which increased with age from 28% in the youngest group to 44.3% in the oldest group. The second most common sign was joint sensitivity to palpation (30.4%), which showed a slight increase in the oldest group. Sensitivity of the superficial muscles was recorded third, with 20%. Joint pain and restriction of mandibular movement appeared infrequently. Two of the more common cardinal symptoms, namely joint sounds and muscle sensitivity, were statistically related to several possible aetiological factors and to age and sex. Analysis of association showed that the probability of muscle sensitivity increased in the presence of malocclusion and/or joint sensitivity to palpation. It also showed that age, occlusal wear, locking of the jaw and joint sensitivity to palpation increased the probability of joint sounds.

Adolescent↗

[Pharmacokinetics of a fluoride-calcium preparation for the treatment of osteoporosis].

The pharmacokinetics of fluoride and calcium were studied after administration of a combined fluoride and calcium preparation (Tridin) (1, 2 and 3 tablets) in 9 healthy male volunteers, using a cross-over study design. The total estimation of the pharmacokinetic data was performed by a simultaneous curve fitting to all single values, using a direct search procedure based on an open two-compartment model and three-compartment model, respectively. Maximum plasma concentrations and areas under the curve are proportional to the dose administered. Inter-subject variations are comparatively small, computerized multiple dose simulation for 3 days does not show any cumulation. The data fit the two-compartment model and the three-compartment model as well. The behaviour of the calcium concentrations reflects the immediate response of calcium homeostasis: plasma calcium concentrations are not affected.

Adult↗

Quantitative assessment of carnitine loss during hemodialysis and hemofiltration.

Carnitine deficiency has been claimed to be responsible for the myo- and cardio-myopathy observed in dialysis patients and has been attributed to the loss of carnitine during dialysis. To quantitate carnitine loss, we determined the carnitine concentrations in 29 patients on chronic hemodialysis, 10 patients on chronic hemofiltration, and 8 patients on CAPD. Mean plasma carnitine levels in hemodialysis and hemofiltration patients (39.8 +/- 2.7 mumoles/liter; N = 39) were significantly lower (P less than 0.01) than in controls (49.8 +/- 2.0 mumoles/liter; N = 43). Hemodialysis or hemofiltration led to a further reduction (33.2 +/- 3.5 mumoles/liter; P less than 0.001). There was no significant difference in the mean plasma carnitine level between CAPD patients (40.0 +/- 5.7 mumoles/liter) and controls. Hemofiltration treatment resulted in a weekly loss of 795 +/- 84 mumoles of carnitine. This was significantly lower (P less than 0.0001) than the urinary carnitine excretion in healthy controls (1534 +/- 134 mumoles per week; N = 27) and the carnitine elimination in the dialysate of CAPD patients (1905 +/- 236.6 mumoles per week; N = 8). It is concluded that carnitine deficiency in dialysis patients cannot be explained by loss into dialysate or filtrate. Because intestinal reabsorption of carnitine does not seem to be impaired, decreased endogenous carnitine synthesis is considered as the most plausible explanation for the moderate degree of carnitine deficiency observed in dialysis patients.

Adult↗

The effect of dimethylsulfoxide on the mutagenicity of the hair dye p-phenylenediamine.

Published data on the mutagenicity of the oxidative hair dye intermediate p-phenylenediamine in the Ames test are conflicting. The work reported here resolves the discrepancies, showing that the activity of p-phenylenediamine in the Ames Salmonella/microsome test is markedly influenced by the use of dimethylsulfoxide as solvent, and by the age of the solution prior to plating. Thus, aqueous solutions of p-phenylenediamine are non-mutagenic; fresh solutions in DMSO are equally non-mutagenic, but become highly active on standing at room temperature for 4 hr. These results suggest the need for caution in the choice of solvents and tight controls in the execution of the test.

Dimethyl Sulfoxide↗

[Biochemical changes with continuous ambulant peritoneal dialysis (CAPD)].

During the past few years continuous ambulatory peritoneal dialysis (CAPD) has become well established in the home treatment of uremia. CAPD, however, may induce certain biochemical abnormalities. Using glucose as an osmotic agent of the dialysate the peritoneal glucose load may vary between 75 and 200 g per day, depending upon how often high osmotic dialysate is needed. If the latter is restricted to one bag per day a long-term disturbance of the glucoregulatory hormones insulin, GIP an glucagon seem to be inprobable. Investigations into glucose tolerance after 23 til 34 months of CAPD treatment in 4 patients did not indicate any exhaustion of the pancreatic beta-cells. Long-term evaluation into the metabolism of lipoproteins, total plasma proteins, aminoacids and trace elements did not show significant abnormalities induced by CAPD itself. Biochemical alterations observed are more or less related to the uremic state of the patients.

Adult↗

The Israeli National Medical Library's new minicomputerized on-line integrated system (MAIMON).

An in-house library system based on a dedicated mini-computer has been in operation in the Israel National Medical Library since the summer of 1979. The integrated system, called MAIMON, features on-line access to bibliographic and circulation records. It replaces manual procedures in cataloging, searching, lending, and reservations. The system provides previously unavailable statistics on items in heavy use and demand, items to be removed from the active collection, and who uses what in the library. It is designed to be user cordial and to save users' time. The system has been very favorably accepted by patrons, and frees professional librarians from time-consuming clerical routine tasks. The system is evaluated in terms of performance, convenience, and cost.

Cost-Benefit Analysis↗

Biochemical studies on patients undergoing continuous ambulatory peritoneal dialysis.

Biochemical studies are being performed in chronically renal insufficient patients undergoing treatment by CAPD. Serum protein and albumin levels have remained stable during treatment as have the ratios of essential/non-essential amino acids and valine/glycine in plasma. Dietary intake therefore appears to adequately compensate dialysate losses. Serum calcium and phosphate as well as immunoreactive parathyroid hormone concentration and alkaline phosphatase levels did not change during the treatment. The glucose load due to the high concentrations of glucose in the dialysate may have adverse effects on the glucose tolerance and insulin secretion of CAPD patients. However, in fasting patients it could be shown that only the 4.25% glucose dialysate causes any increase in plasma glucose levels with a concommitant rise of insulin secretion, an exchange with a 1.5% glucose dialysate having relatively little effect on these parameters. Quantification of the individual serum lipoproteins is also being performed during CAPD. No changes were observed in alpha-cholesterol levels, but 50% of the patients have shown significant increases in total serum cholesterol, beta-cholesterol and serum triglycerides in the course of treatment. In these cases dietary consequences must be considered in order to minimise the potential artherosclerotic risk.

Adolescent↗

[First observations with continuous ambulatory peritoneal dialysis (author's transl)].

Continuous ambulatory peritoneal diaglysis (CAPD) represents a new method for treatment of chronic renal failure whereby patients carry two litres of dialysate with them permanently and are freely mobile. Dialysis is only interrupted by exchange of dialysate in approximately 6-hourly intervals. Due to the long presence of the dialysate in the peritoneal cavity clearance values are superior to intermittent peritoneal dialysis for small-molecular substances and reach elimination values of haemofiltration for medium-molecular substances. The main technical requirements consist of a permanent peritoneal dialysis catheter linked to a plastic dialysate bag by way of a connecting tube. In order to avoid frequent change of bag and thus increased risk of peritonitis bags are folded and carried on the body of the patient during the interval. Thereafter the bag is unfolded, filled with used dialysate and exchanged for a new bag. Six patients were thus treated for over 34 patient-months so far. Changes of chemical pathology were readily acceptable. Even though CAPD has several advantages over conventional dialysis as they are mainly founded on the high degree of rehabilitation of patients, risk of peritonitis is still a considerable factor of uncertainty.

Abdomen↗

Identification of palindromic sequences recognized by restriction endonucleases, as based on the tabularized sequencing data for seven viral and plasmid DNAs.

Computer search of DNA sequences for phages phi X174, G4, M13 and fd, plasmids pBR322 and pAO3, and virus SV40, was employed to prepare tables specifying the size classes and frequencies of DNA segments located between all possible tetra-, penta- and hexanucleotide palindromes. As described earlier (Fuchs et al., 1978), these tables permit identifying sequences recognized by most of the restriction endonucleases. The effect of sequencing errors on the accuracy of the present identification method is evaluated. Only four of the 224 listed sequences do not appear in any of the seven DNAs, leading to discussion (see Appendix) on the natural sequence distribution.

Bacteriophage phi X 174↗

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↗