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Biomedical subjects

C Peters

Publications and source records attributed to C Peters.

At least 253 records · Page 14Linked to original sources

Patient and graft survival in amputated versus nonamputated diabetic primary renal allograft recipients.

Between September 23, 1968 and March 22, 1980, primary renal allografts were performed in 373 uremic patients with insulin-dependent diabetes. After transplantation 65 of the diabetic patients (17%) underwent 151 amputations involving at least a digit or a limb. The lower extremity was involved in 72% of the amputations. Twenty-four patients had only one procedure, while 41 required multiple procedures. Mean interval from transplantation to first amputation was 25.2 +/- 2.4 (SE) months. Patient and graft loss (perioperative risk) in the first 3 months after amputation was 13%. Diabetic renal allograft recipients living long enough to require amputation have more severe manifestations of vascular disease. These amputees display both an 11% lower patient and graft survival after the first year following transplantation, as well as an accelerated rate of graft loss following amputation. Those diabetics requiring an amputation do significantly more poorly than nonamputees of the corresponding demographic category if diabetes onset occurred at age 10 to 20 years, diabetes duration prior to transplant was less than 20 years, age at transplant was less than 30 years, dialysis duration was less than 4 months, and donor type was HLA-nonidentical related. Nevertheless, more than 50% of the diabetics undergoing amputation will be alive with functioning allografts 4 years after amputation. On the other hand, diabetics not requiring amputation do particularly well if they survive 1 year, with more than 80% chance that they will be alive with a functioning graft 4 years after transplantation.

Adult↗

Studies on calorie to nitrogen ratio for total parenteral nutrition.

In this study, three calorie nitrogen ratios, 102:1, 163:1 and 204:1, were analyzed in 40 week long study periods in a total of approximately 22 stable patients without sepsis who required parenteral nutrition. A calorie to nitrogen ratio of 163:1 appeared to be most efficacious for nitrogen equilibrium in these patients studied. A calorie to nitrogen ratio of 102:1 was associated with weight loss and negative nitrogen balance. Conversely, increasing the calorie to nitrogen ratio to 204:1, at least for this group of patients, did not result in improved nitrogen retention. Different methods of calculation of nitrogen equilibrium are presented, depending upon the disease state and the method by which data analysis is carried out. The results suggest that different levels of nitrogen and caloric input as well as calorie to nitrogen ratio may be appropriate in different disease states.

Adult↗

Testosterone secretion by rat, rabbit, guinea pig, dog, and hamster testes perfused in vitro: correlation with Leydig cell mass.

Testes from guinea pigs, rabbits, dogs, rats, and hamsters perfused in vitro with maximally stimulating concentrations of ovine LH released 9.76 +/- 2.05, 12.80 +/- 3.15, 28.94 +/- 3.01, 3.18 +/- 0.41, and 0.70 +/- 0.12 microgram testosterone (T)/h, respectively. Adjusting for differences in testicular weight did not eliminate significant (P less than 0.01) species variation in testicular capacity for T secretion in response to ovine LH. Similarly, correction for Leydig cell mass, as determined by morphometric analysis, still left significant (P less than 0.01) differences in the testosterone secretion rates in response to ovine LH for guinea pigs (262.5 +/- 38.6 micrograms T/g Leydig cell), rabbits (205.5 +/- 50.7 micrograms T/g Leydig cell), dogs (116.4 +/- 14.8 micrograms T/g Leydig cell), rats (83.55 +/- 21.80 micrograms T/g Leydig cell), and hamsters (18.24 +/- 3.55 micrograms T/g Leydig cell). The data suggest that significant between-species variation of T production in response to ovine LH is not due to quantitative differences in the mass of Leydig cells.

Animals↗

Postfertilization poly(A) . protein complex formation on sea urchin maternal messenger RNA.

A two-fold increase in polyadenylate [poly(A)] content occurs between fertilization and the two-cell stage in sea urchin zygotes. In this report the role of this cytoplasmic polyadenylation process in the provision of binding sites for poly(A)-associated proteins during early development of Lytechinus pictus is evaluated. Protein-associated poly(A) sequences, from ribonuclease-treated, post-mitochondrial supernatants of various developmental stages, were collected by nitrocellulose filtration and quantified by 3H-poly(U) complex formation. The proportion of protein-associated poly(A) rose from about 27% to about 60% of the total poly(A), on a nucleotide basis, during the period between fertilization and the eight-cell stage. However, the actual increase in number of poly(A) sequences associated with protein was more extensive, about 2.5-fold, since protein-associated poly(A) sequences average about 45 nucleotides longer than free poly(A). The protein-associated poly(A) of eggs and zygotes is found in two types of protease-sensitive complexes which sediment at 8--12 S and 15--20 S. The 8--12 S complex appears to be selectively increased in amount following fertilization. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the poly(A) protein complex fraction indicates the presence of 87,000 and 130,000 molecular weight polypeptides in both eggs and zygotes. It is concluded that quantitative, but not qualitative, alterations in the proportion of protein-associated poly(A) accompanies post-fertilization cytoplasmic polyadenylation in sea urchin zygotes. The attachment of specific proteins to the 3' terminus of maternal RNA's may be involved in their subsequent activities during early embryogenesis.

Animals↗

[Use in histological technic of naphtol AS-D chloroacetate for demonstration of granulocyte series elements].

The authors report their experience of a histo-enzymatic method, using Naphtol AS-D Chloroacetate as a substrate, for the specific demonstration of elements of the granulocyte series, in histological sections, after formol fixation and mounting in paraffin wax. This simple and reliable staining technique offers the possibility of very rapid diagnostic orientation in haematological conditions.

Bone Marrow Cells↗

Functional and metabolic properties of human asialofibrinogen.

The role of sialic acid in the functional and metabolic properties of purified human fibrinogen was investigated. Fibrinogen treated with Vibrio cholerae neuraminidase released 90 percent of its sialic acid without evidence of proteolysis, as indicated by the presence of intace A alpha, B beta, and gamma chains on sodium dodecylsulfate (SDS)-polyacrylamide gels of the reduced asialoprotein. The thrombin and Reptilase clotting times of human asialofibrinogen were shortened compared to those of normal fibrinogen. Fibrinopeptide release was normal in rate and amount, but asialofibrin monomer aggregation was increased at both low and high ionic strength. Similarly, the asialo-derivative of fibrinogen Philadelphia (functionally characterized by impairment of fibrin monomer aggregation) demonstrated shortening of its thrombin and Reptilase times and improvement in its monomer aggregation especially at high ionic strength. Asialofibrin showed a normal capacity to form cross-linked fibrin as demonstrated by normal gamma-chain dimerization and alpha-chain polymerization. Simultaneous metabolic studies of human normal fibrinogen and asialofibrinogen in rabbits revealed only a modest decrease in the half-life of the asialoprotein compared to the intact protein, with no preferential uptake of the asialo-derivative by the liver. Control studies with rabbit normal fibrinogen and asialofibrinogen in rabbits revealed the same modest difference in half-life. Thus, asialofibrinogen clots faster due to enhancement of its monomer aggregation, has a normal capacity to form cross-linked fibrin, and does not differ significantly in its metabolic properties from normal fibrinogen. The possible influence of sialic acid in the functional abnormality of some congenital dysfibrinogenemias is discussed.

Blood Coagulation Tests↗

Monitoring genomic alterations with a panel of oligonucleotide probes specific for various simple repeat motifs.

Germline and somatic instability of the human genome was studied, using synthetic oligonucleotides specific for simple repeat motifs. The following probes were used: (GTG)5, (GACA)4, (GATA)4, (CT)8, (TTAGGG)3, (GT)8, (GAA)6 and (GGAT)4. Each of them is unique with respect to the target regions recognized in the genome. Thus compilation of the various fingerprint data provides a complex map of the genome (and its deviations). While the fingerprints of differentiated somatic tissues never showed any alterations, in tumor tissues (namely gliomas) many changes could be detected. Most of the latter reflect secondary karyological aberrations. In nearly one third of the gliomas, drastically amplified and apparently monomorphic DNA fragments were identified. This marker should make it possible to deal with causal pathogenetic mechanisms as well as novel diagnostic strategies.

Base Sequence↗