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Biomedical subjects

A Kunzmann

Publications and source records attributed to A Kunzmann.

15 recordsLinked to original sources
PubMed1998

The hemoglobins of the antarctic fishes Atedidraco orianae and Pogonophryne scotti. Amino acid sequence, lack of cooperativity, and ligand binding properties.

The oxygen-transport system of two species of Antarctic fishes belonging to the family Artedidraconidae, Artedidraco orianae and Pogonophryne scotti, was thoroughly investigated. The complete amino acid sequence of the alpha and beta chains of the single hemoglobins of the two species was established. The oxygen-binding properties were also investigated, and were found not to differ significantly from those shown by blood, intact erythrocytes, and unstripped hemolysates. Both hemoglobins have unusually high oxygen affinity and display a relatively small Bohr effect; the Root effect is elicited only by organophosphates and is also reduced. Remarkably, the Hill coefficient is close to one in the whole pH range, indicating absence of cooperative oxygen binding which, in A. orianae hemoglobin, could be ascribed to the subunit heterogeneity shown upon oxygen dissociation. In comparison with the other families of the suborder Notothenioidei, the oxygen-transport system of these two species of Artedidraconidae has unique characteristics, which raise interesting questions on the mode of function of a multisubunit molecule and the relationship with cold adaptation.

Amino Acid Sequence↗
PubMed1998

5' end maturation and RNA editing have to precede tRNA 3' processing in plant mitochondria.

We report the characterization and partial purification of potato mitochondrial RNase Z, an endonuclease that generates mature tRNA 3' ends. The enzyme consists of one (or more) protein(s) without RNA subunits. Products of the processing reaction are tRNA molecules with 3' terminal hydroxyl groups and 3' trailers with 5' terminal phosphates. The main processing sites are located immediately 3' to the discriminator and one nucleotide further downstream. This endonucleolytic processing at and close to the tRNA 3' end in potato mitochondria suggests a higher similarity to the eukaryotic than to the prokaryotic tRNA 3' processing pathway. Partial purification and separation of RNase Z from the 5' processing activity RNase P allowed us to determine biochemical characteristics of the enzyme. The activity is stable over broad pH and temperature ranges, with peak activity at pH 8 and 30 degrees C. Optimal concentrations for MgCl2 and KCl are 5 mM and 30 mM, respectively. The potato mitochondrial RNase Z accepts only tRNA precursors with mature 5' ends. The precursor for tRNAPhe requires RNA editing for efficient processing by RNase Z.

Base Sequence↗
PubMed1997

The hemoglobin system of Pleuragramma antarcticum: correlation of hematological and biochemical adaptations with life style.

The hematological properties and the oxygen-transport system of the antarctic fish Pleuragramma antarcticum were investigated. Most blood parameters are at the lower end of the range of values known for red-blooded antarctic fish, suggesting a link with the sluggish mode of life of this species. P. antarcticum is the only species of the family Nototheniidae and of the suborder Notothenioidei having three major hemoglobins, which were isolated and fully characterized. The complete amino acid sequence of the alpha- and beta-globin chains was determined. The three hemoglobins showed strong Bohr and Root effects, and their oxygen-binding properties were differently regulated by temperature. None of the three hemoglobins of P. antarcticum can be considered as evolutionary (or larval) remnants. Therefore, this oxygen-transport system is one of the most specialized ever found in fish. The data suggest a strong relationship between hematological/biochemical adaptation and life style.

Adaptation, Physiological↗
PubMed1997

Four new bioactive polybrominated diphenyl ethers of the sponge Dysidea herbacea from West Sumatra, Indonesia.

The marine sponge Dysidea herbacea collected from Indonesia yielded four new polybrominated diphenyl ether congeners 2-5 and the known derivatives 1, 6, and 7. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct and long-range 13C-1H correlations) and mass spectrometric (EIMS) data. All of the compounds were active against the Gram-positive bacteria Bacillus subtilis and the phytopathogenic fungus Cladosporium cucumerinum. The isolated polybrominated compounds were also active in the brine shrimp lethality test. In the latter bioassay, compounds 1 and 6 were the most active with LC50's of 0.96 [SE +/- 0.19] and 0.94 [SE +/- 0.70] microg/mL, respectively.

Animals↗
PubMed1996

The unique hemoglobin system of Pleuragramma antarcticum, an antarctic migratory teleost. Structure and function of the three components.

Pleuragramma antarcticum (suborder Notothenioidei, family Nototheniidae) is the most abundant fish in the antarctic shelf. This pelagic species has a circum-antarctic distribution and is characterized by spawning migration. This species displays the highest multiplicity of major hemoglobins (three); the other notothenioids have a single one (except one species, having two) with relatively low oxygen affinity regulated by pH and organophosphates. The hemoglobins of P. antarcticum display strong Bohr and Root effects; however, they reveal important functional differences in subunit cooperativity and organophosphate regulation and, above all, in the response of oxygenation to temperature. Despite the substitution ValbetaE11 --> Ile found in Hb 2, which decreases the affinity in human mutants, the hemoglobins have similar oxygen affinity, higher than that of the other notothenioids. Hb 1 has the alpha chain in common with Hb 2 and the beta in common with Hb 3. The amino acid sequence of all four chains has been established. Thus the hematological features of P. antarcticum differ remarkably from those of antarctic notothenioids. This unique and sophisticated oxygen transport system may adequately meet the requirements of the unusual mode of life of this fish.

Allosteric Regulation↗
PubMed1992

The amino acid sequence of the single hemoglobin of the high-antarctic fish Bathydraco marri Norman.

1. Bathydraco marri Norman is a cold-adapted Antarctic teleost (Family: Bathydraconidae), living preferably at depths between 400 and 1200 m. 2. The blood of this species contains a single hemoglobin, in which oxygen binding is pH-regulated (Bohr and Root effects). 3. The complete amino acid sequence of the alpha and beta chains of the hemoglobin of B. marri has been elucidated.

Acylation↗
PubMed1979

Texture patterns in pancreatic sonograms.

In a retrospective study of 163 pancreatic sonograms, five internal echo patterns were correlated with the ultimate clinical diagnoses. Attention to the internal echo patterns of the pancreas can provide useful information in diagnosing pancreatic disease, including identification of abnormalities in glands of normal size and contour.

Humans↗
PubMed1978

Prospective evaluation of gray scale ultrasonography in the diagnosis of pancreas cancer.

One hundred thirty-four patients suspected of having pancreas cancer successfully underwent gray scale ultrasound examination of the pancreas. The prospective ultrasound findings were correlated with the final diagnoses, laparotomy findings, and pathology findings. Fifty-four patients had pancreas cancer, confirmed by resection or biopsy in all cases. On ultrasonography, the pancreas was correctly reported to have abnormalities in sixty-one of seventy-eight patients (78 per cent) and correctly reported to have no abnornalities in thirty-eight of fifty-six patients (68 per cent). A correct ultrasound diagnosis of pancreas cancer was made for forty-four of fifty-six patients (81 per cent), and there were thirteen false-positive reports. Ninety-four percent of cancers confined to the head of the pancreas and 70 per cent of cancers at other locations within the gland were detected by ultrasound examination. The correct ultrasound diagnosis was given for fifteen of seventeen patients with resectable pancreas cancer, the degree of associated pancreatitis ranging from minimal to severe. Analysis of the predictive values of positive and negative ultrasound examinations suggests that this test could be used to screen a population of patients with symptoms mildly suggestive of pancreas cancer. The importance of preselecting the level of confidence of a positive test result, a,ove which further investigation is indicated, is emphasized.

Diagnosis, Differential↗
PubMed1978

Accuracy of placental localization by ultrasound.

In a retrospective study, ultrasound diagnoses were correct in 93% of 164 patients referred for examination because of suspected placenta praevia. There was one false-negative finding in 13 cases of proven placenta praevia, and ten false-positive errors in 151 true-negative cases. False-positive results represented the largest number of errors. Examination of the patient with an empty bladder, in addition to the routine technique, is suggested to reduce the number of false-positive results.

Diagnostic Errors↗
PubMed1977

Ultrasound in the staging of lymphoma.

Ultrasonography of the abdomen and pelvis was performed in 16 patients with lymphoma who underwent clinical and pathologic staging. The results of the ultrasound examinations were correlated with the pathological findings as were the results of gallium-67 scans, inferior vena cavagrams and lymphangiograms obtained in the same group. Analysis of the data indicated accuracies in the 80-90% range and specificities of greater than 90% for ultrasound. The sensitivity of ultrasound was somewhat lower, in the 60-70% range. These findings compare favorably with those of the other diagnostic procedures evaluated and indicate the usefulness of ultrasound in the staging of lymphoma.

Gallium Radioisotopes↗
PubMed1977

Changes with age in muscular pulmonary arteries.

The mean wall thickness, in relation to the external diameter, of 100 muscular arteries distended by barium gelatin at 100cm H2O pressure was calculated in "normal" lungs from patients who ranged in age from 3 to 79 years. For normal vessels less than 2 mm in diameter the mean was 2.4% of the external diameter. The mean for vessels in the five persons under 40 years was 1.8% but it was 2.8% for the five older individuals. Although this difference may reflect some increased muscularity with age, some of the increment may be related to a reduced distensibility of vessels caused by the accumulation of interstitial fluid, as manifested by increased weight in the older lungs. Intimal fibrosis was found to increase with age but occurred in less than 50% of the vessels measured.

Adolescent↗
PubMed1977

Muscular pulmonary arteries in chronic obstructive lung disease.

The small muscular pulmonary arteries are thought to be normal in obstructive pulmonary disease despite prolonged hypoxic stimulation to medial thickening. Because measurements on nondistended vessels have considerable variability, we reinvestigated the problem by studying the percentage of wall thickness of distended arteries in lungs taken post mortem from 5 asymptomatic emphysematous patients and 11 symptomatic patients with obstructive pulmonary disease. Vessels in the former patients had normal medial thicknesses. In contrast, we found an elevated mean percentage of wall thickness for vessels between 0.3 and 2.0 mm in diameter of 4.46% +/-1.44% (mean +/-SD) for patients with obstructive airways disease. Obstructive pulmonary disease, therefore, produced medial hypertrophy in small muscular arteries similar to that seen in other conditions associated with chronic hypoxia.

Aged↗