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Biomedical subjects

A Montag

Publications and source records attributed to A Montag.

43 records · Page 3Linked to original sources
PubMed1988

A 5- to 21-year follow-up and analysis of 250 patients with rectal adenocarcinoma.

A total of 250 patients with rectal adenocarcinoma were operated on at the University of Chicago Medical Center between 1965 and 1981. The operation performed was curative resection in 154 patients, palliative resection in 16 patients, diverting colostomy in 21 patients, exploratory laparotomy in 11 patients, and transanal removal in 48 patients. Of the 154 curative resections, 115 were abdomino-perineal (APR), three were total proctocolectomies, and 36 were low anterior resections (LAR). No anastomotic complications were observed in this latter group. Operative mortality was 3%. Complete follow-up was obtained in 152 patients (98.7%). Five- and 10-year actuarial survival rates were 68.8 and 59.4%, respectively, for patients with Dukes' B1 adenocarcinoma (n = 32), 55.8 and 44.2% for Dukes' B2 tumors (n = 52), and 42.9% and 25.4% for Dukes' C tumors (n = 63). Distant metastases developed in 59 patients (39.6%), and pelvic recurrence developed in another 18 patients (12%); 5-year survival rates were 23.6% and 22.2%, respectively. Multivariate analysis with Cox regression showed that stage (p = 0.0001), race (p = 0.03), tumor morphology (p = 0.02), and vascular and/or lymphatic microinvasion (p = 0.001) were statistically significant in their association with survival. Logistic regression analysis confirmed these results and allowed for the estimation of 5-year survival probabilities in 16 groups of patients defined by various associations of these four factors. These estimates ranged from a high of 92% in Caucasian patients with Stage B, exophytic tumors with no vascular or lymphatic microinvasion, to a low of 14% in black patients with Stage C, nonexophytic tumors and with the presence of vascular and/or lymphatic microinvasion. Univariate analysis showed that histologic type (p = 0.0006), stage (p = 0.05) and vascular and/or lymphatic microinvasion (p less than 0.001) were significantly associated with the incidence of pelvic recurrence. Analysis of the extent of the operation revealed that the incidence of pelvic recurrence was reduced by the performance of a wide pelvic lymphadenectomy (9.4% vs. 16.4%), but the result did not reach statistical significance (p = 0.16). In conclusion, this study confirms the well-established prognostic value of the Dukes' staging classification of rectal carcinoma. Further, the analysis reveals that race, tumor morphology, and the presence or absence of lymphatic and/or vascular microinvasion significantly influence outcome. By associating these four statistically significant and independent variables, the prognosis for any individual patient can be estimated more precisely than by using Dukes' staging alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1988

Importance of tumor morphology for the long term prognosis of rectal adenocarcinoma.

A retrospective review of 149 consecutive potentially curable rectal adenocarcinomas operated on at our institution between 1965 and 1981 was carried out to assess whether tumor morphology influences long term survival. Complete follow-up was available on all patients and extended to 20 years. Data on tumor morphology was extracted from pathology reports and was available in 147 cases (98.6%). Tumors were defined as exophytic (n = 76) when exhibiting a polypoid growth pattern protruding into the lumen at least 1 cm; when lacking such characteristic growth pattern, tumors were classified under the general term of nonexophytic (n = 71). The 5 year survival rate calculated with life table analysis was 80 per cent for exophytic carcinomas and 54.1 per cent for nonexophytic tumors. This difference was verified by logistic regression analysis and proportional hazard technique and is statistically highly significant (P = 0.001). The rate of distant metastases was 29.7 per cent for exophytic adenocarcinoma and 48.6 per cent for nonexophytic tumors (P = 0.02). Although the results did not reach statistical significance, local recurrence of tumor occurred about twice as often in nonexophytic tumors (15.7%) compared with exophytic tumors (8.1%). Thus, we conclude that tumor morphology is an important preoperative prognostic factor for survival and prediction of distant metastasis, and possibly for local recurrence.

Actuarial Analysis↗
PubMed1987

[Principles of the hydrolysis of bound purine and pyrimidine bases in foods and program-controlled calculation of nucleic acid content].

In order to determine the amount of combined purine and pyrimidine bases in foods we investigated the chemical fundamentals of their hydrolytic digestion it was demonstrated that the digestion mixture used, containing trifluoracetic- and formic acids, protected the purine bases during hydrolysis from oxidative degradation due to carbon monoxide formation. Further, a time-saving computer-program was developed and presented. This program allows, depending on the purine composition, the calculation of the corresponding nucleic acids, the nucleotides and the purine-nitrogen-content of the food.

Computers↗
PubMed1987

[Determination of individual purine and pyrimidine bases in carbohydrate-rich food].

The following method was developed for the qualitative and quantitative determination of purine and pyrimidine bases in carbohydrate rich food: The bases were liberated from nucleic acids, nucleotides or nucleosides by acid hydrolysis in a pressure digestion vessel. A complete liberation without losses of purine bases occurs upon hydrolysis for 15 min at 240 degrees C with trifluoroacetic and formic acids (1+1; V + V), pyrimidine bases need 45 min at 240 degrees C. The products arising from side reactions (such as hydroxymethylfurfural from hexoses and furfural from pentoses) could be removed from the hydrolysate by extraction with dichlormethane. The liberated bases could be separated upon stepwise elution by cation exchange chromatography. They were detected and determined by UV-measurements, continuously monitoring at lambda = 260 nm, and integrating electronically. The evaluation was carried out by a method with internal standard.

Chromatography, Ion Exchange↗
PubMed1987

[Nucleo-compounds in protein-rich food].

The content of nucleo-compounds was investigated in protein rich food by the analytical methods as reported in previous publications. The data obtained for nucleobases (purines and pyrimidines) as well as the contents of nucleic acids (RNA, DNA) calculated therefrom and the content of IMP corresponding to the determined content of hypoxanthine are reported in three tables. The experimental data show remarkable alterations that have occurred on the nucleo-compounds in heat-treated food. The investigation of some sea-fishes pointed out the high content of hypoxanthine and guanine, and a low content of nucleic acids.

Dietary Proteins↗
PubMed1985

Transport of Ca2+ and Mn2+ by mitochondria from rat liver, heart and brain.

The energy-dependent, respiration-supported uptake and the uncoupler- or Na+-induced release of Ca2+ and Mn2+ by mitochondria from rat liver, heart and brain were investigated, using as indicators radioisotopes (45Ca and 54Mn), proton ejection, oxygen consumption, nicotinamide nucleotide oxidation-reduction and, in the case of Ca2+, the metallochromic dye Arsenazo III. Ca2+ uptake in the presence of Pi was rapid in mitochondria from liver and brain, and less rapid in those from heart. Mn2+ uptake was much slower than that of Ca2+ in liver and heart, but only slightly slower in brain. When added together, Ca2+ accelerated the uptake of Mn2+, and Mn2+ retarded the uptake of Ca2+, by mitochondria from all three tissues. When Mn2+ was present during Ca2+ uptake, its own uptake remained accelerated even after Ca2+ uptake was terminated. Mg2+, which was not taken up, inhibited Ca2+ uptake by mitochondria from all three tissues, and, when present during Ca2+ uptake, accelerated the subsequent uptake of Mn2+. The uncoupler CCCP induced a release of both Ca2+ and Mn2+ from all three sources of mitochondria; yet, release of Mn2+ took place only in the absence of Pi. The release followed the same pattern as the uptake, i.e., Ca2+ accelerated the release of Mn2+ and Mn2+ retarded the release of Ca2+. Na+ induced a release of both Ca2+ and Mn2+ from heart and brain but not from liver mitochondria; again, Mn2+ release occurred only in the absence of Pi. The Na+-induced release of Ca2+ was inhibited by Mn2+, but the Na+-induced release of Mn2+ was not accelerated by Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗