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Biomedical subjects

M Klein

Publications and source records attributed to M Klein.

At least 361 records · Page 20Linked to original sources
PubMed1993

Post-translational processing and Thr-206 are required for glycosylasparaginase activity.

Lysosomal glycosylasparaginase is encoded as a 36.5 kDa polypeptide that is post-translationally processed to subunits of 19.5 kDa (heavy) and 15 kDa (light). Recombinant glycosylasparaginase has been expressed in Spodoptera frugiperda insect cells enabling the precursor and processed forms to be isolated and their catalytic potential determined. Only the subunit conformation was functional indicating glycosylasparaginase is encoded as an inactive zymogen. The newly created amino terminal residue of the light subunit following maturation, Thr-206, is believed to be involved in the catalytic mechanism [1992, J. Biol. Chem. 267, 6855-6858]. Here we have constructed two amino acid substitution mutants replacing Thr-206 with Ala-206 or Ser-206 and demonstrate that both destroy enzyme activity.

Amino Acid Sequence↗
PubMed1993

Use of DNA end joining activity of a Xenopus laevis egg extract for construction of deletions and expression vectors for HIV-1 Tat and Rev proteins.

We have developed a cloning strategy which combines conventional T4 DNA ligation with the highly efficient nonhomologous DNA end joining (EJ) activity of an extract from Xenopus laevis eggs. The nonhomologous EJ activity allowed the rapid construction of deletion mutants by the intramolecular rejoining of nonhomologous DNA ends generated for the purpose of deleting restriction fragments from the vector. The combined use of T4 DNA ligase for intermolecular ligation and X. laevis egg extracts for intramolecular nonhomologous EJ proved to be a powerful tool, as demonstrated here for the construction of expression vectors for HIV-1 Tat and Rev.

Animals↗
PubMed1993

[The energetic utilization of L-fructose in rats].

The energetic utilization of L-fructose (LF) and D-fructose (DF) was investigated by means of indirect calorimetry in a difference trial on 9 male Wistar rats in the live weight range of 250 to 300 g. The daily rations in the two comparable periods with added fructose consisted of 10 g basal diet plus 2.7 g LF or 2.5 g DF. The digestibility and metabolizability of energy of the LF-ration were decreased by about 4 and 6%, resp., in comparison to the DF-ration. The efficiency of total utilization of energy (energy deposition/gross energy) amounted to (7 +/- 3)% (mean +/- SD) for the LF-ration and (10 +/- 3)% for the DF-ration. The lower digestibility of energy of the LF-ration was mainly due to a depression of apparent digestibility of crude protein, crude fat and crude fibre--obviously caused by increased microbial fermentation. With correction of the depression of digestibility the following values of energetic utilization resulted from the difference evaluation for LF and DF, resp.: digestibility (90 +/- 8)% and (100 +/- 6)%, metabolizability (85 +/- 8)% and (102 +/- 5)%, utilization of gross energy for energy deposition (69 +/- 11)% and (86 +/- 11)% and utilization of metabolizable energy (81 +/- 7)% and (84 +/- 11)%, resp.

Animals↗
PubMed1993

Genome structure of a virus infecting the marine brown alga Ectocarpus siliculosus.

We describe a procedure for the isolation of virus particles from the marine brown alga Ectocarpus siliculosus. Virus particles are composed of at least 13 different polypeptides, including two glycoproteins, and double-stranded DNA. A typical virus DNA preparation contains three fractions, namely linear DNA and circular DNA, each composed of about 320 kilobase pairs, as well as DNA fragments, 10 to 60 kilobase pairs in size. The large linear and the circular DNA contain single-stranded regions (average length: 2.9 kilobase). We propose that the native Ectocarpus virus genome is a circular DNA molecule whose double strand is interrupted by single-stranded regions. During the preparation procedure, the DNA circles tend to break at the single-stranded sites producing large linear as well as fragmented DNA.

DNA, Viral↗
PubMed1993

Radical lymphadenectomy in the primary carcinoma of the fallopian tube.

The primary carcinoma of the Fallopian tube is a highly aggressive tumor which can spread by the lymphatic route. The object of the present study was to evaluate the impact of radical pelvic and para-aortic lymphadenectomy on overall survival. Radical lymphadenectomy was performed on twelve patients in addition to hysterectomy and bilateral adnexectomy (group I). Twenty-eight patients subjected only to hysterectomy and adnexectomy formed the control group (group II). On average 47.6 lymph nodes were excised per patient. As long as the carcinoma was limited to adnexa and uterus (stages I and II), no lymph node metastases were found, only in stages III and IV were lymph node metastases detectable. Even though the median survival time of group I was considerably higher than of group II (43 versus 35 months), there was no statistically significant difference between the two groups (P < 0.65). Patients with stage III and stage IV disease had relatively longer median survival times if they had a lymphadenectomy. However, the difference was not statistically significant (P < 0.91). We cannot therefore recommend routine radical lymphadenectomy for primary Fallopian tube carcinoma. Whether or not lymph node dissection would lead to better results from rational selection of patient for adjuvant therapy is not known.

Fallopian Tube Neoplasms↗
PubMed1993

Surgical relief of acute airway obstruction due to primary tuberculosis.

Primary pulmonary tuberculosis in children remains a leading cause of mortality and morbidity in developing countries. Thirteen children requiring urgent thoracotomy for relief of acute respiratory distress resulting from critical major airway narrowing caused by enlarged tuberculous mediastinal lymph nodes were admitted to two hospitals over a 4-year period. Ages ranged from 2 months to 10 years. The condition of each patient had deteriorated despite appropriate antituberculosis therapy and an oral corticosteroid. At operation, the enlarged tuberculous subcarinal or paratracheal lymph nodes or both were decompressed. Surgical complications included a bronchial tear and a pulmonary artery laceration. Additional procedures included a right upper lobectomy, two pneumonectomies, plication of a hemidiaphragm, and mobilization of two muscle flaps. Postoperatively all children showed dramatic improvement. The trachea to main bronchi diameter ratio improved by 49.1% on the left and 44.9% on the right in the immediate postoperative period. In children with respiratory distress produced by compression of the main bronchi between enlarged subcarinal and paratracheal lymph nodes, surgical decompression of the lymph nodes is indicated if there is no marked initial response to appropriate medical therapy. At operation, lymph nodes should be decompressed only by incision and curettage. Attempts at lymph node excision are associated with increased complications.

Acute Disease↗
PubMed1993

Activation of neurohumoral systems in postinfarction left ventricular dysfunction.

OBJECTIVES: This study was conducted to evaluate the degree of neurohumoral activation around the time of hospital discharge after myocardial infarction. BACKGROUND: Because pharmacologic interventions that block the effects of neurohumoral activation improve the prognosis after infarction, we hypothesized that widespread neurohumoral activation persists in some patients until at least the time of hospital discharge and that the determinants of activation vary from one system to another. METHODS: Five hundred nineteen patients in the Survival and Ventricular Enlargement Study (SAVE) had plasma neurohormones measured before randomization at a mean of 12 days after infarction. All patients had left ventricular dysfunction (left ventricular ejection fraction < or = 40%) but no overt heart failure. RESULTS: Although all neurohormones except epinephrine were increased compared with values in age-matched control subjects, plasma norepinephrine (301 +/- 193 vs. 222 +/- 87 pg/ml, p < 0.001), renin activity (3.0 +/- 3.7 vs. 1.2 +/- 1.2 ng/ml per h, p < 0.001), arginine vasopressin (1.9 +/- 6.9 vs. 0.7 +/- 0.3 pg/ml, p < 0.001) and atrial natriuretic peptide (75 +/- 75 vs. 21 +/- 9 pg/ml, p < 0.001) values ranged from normal to very high, indicating a wide spectrum of neurohumoral activation. Activation of one system did not correlate with activation of another. The clinical and laboratory variables most closely associated with neurohumoral activation were Killip class, left ventricular ejection fraction, age and use of diuretic drugs. The association between neurohumoral activation and clinical and laboratory variables varied from one neurohormone to another. CONCLUSIONS: Neurohumoral activation occurs in a significant proportion of patients at the time of hospital discharge after infarction. Which neurohormone is activated and which clinical and laboratory variables determine this activation vary from one neurohormone to another.

Aged↗
PubMed1993

HER-2 and INT-2 amplification estimated by quantitative PCR in paraffin-embedded ovarian cancer tissue samples.

Competitive polymerase chain reaction (PCR) systems were developed for rapid and quantitative estimation of HER-2 (c-erbB-2) and INT-2 oncogene amplification in paraffin-embedded ovarian cancer tissue samples. The beta-globin gene was used as reference and DNA from paraffin-embedded placenta tissue as single copy control. Reliability of the PCR method could be demonstrated by comparing dot blot data with PCR data of identical tumour samples. The PCR method was used to determine HER-2 and INT-2 copy numbers in 196 ovarian cancer samples. HER-2 and INT-2 were found to be amplified in 40 and 19%, respectively. In 8% HER-2 copy numbers were greater than five, but no high INT-2 copies were noted. Kaplan-Meier estimates did not reveal significant association with overall survival. Indirect correlation between HER-2 and INT-2 amplification was observed. The present PCR system is a valuable method for prospective and retrospective studies.

Base Sequence↗
PubMed1993

[Physiopathology of inorganic lead poisoning].

This paper gives an overview of the hypotheses concerning the mechanisms of inorganic lead toxicity on cells and tissues, with emphasis on the effect of low-concentration lead. Inhibition of heme synthesis is responsible not only for lead-induced anaemia, but also for accumulation of delta-aminolaevulinic acid (ALA) and for lowering the concentration of cytochromes contained in the mitochondrial respiratory chain. Auto-oxidation of ALA is thought to result in the formation of free radicals. On the other hand, lead replaces ionic calcium in its role as second cell messenger. This mechanism would explain the abnormalities observed in synaptic transmission, arteriolar vasoreactivity and functioning of such cells as osteoclasts and osteoblasts. Nuclear toxicity, with abnormal expression of DNA genes and inhibition of certain enzymes such as membrane Na+/K+ ATPase, are also considered. The mechanisms of tissue toxicity are discussed.

Humans↗
PubMed1993

First experience with FGF-3 (INT-2) amplification in women with epithelial ovarian cancer.

Estimation of FGF-3 oncogene amplification in DNA samples extracted from paraffin embedded sections of 136 ovarian cancer samples was carried out by a quantitative PCR method. The aim of this study was to elucidate a possible association of FGF-3 copy numbers with established prognostic factors such as age, histology, FIGO stage, grading, postoperative residual tumour mass, ascites, hormone receptor content and preoperative CA 125 serum levels. In addition, correlation of FGF-3 amplification with overall survival of the patients was assessed. There was a borderline positive correlation between preoperative CA 125 serum levels and the degree of amplification of the FGF-3 gene (P = 0.06). A statistically significant association of FIGO-stage with FGF-3 copy number could be found (P = 0.008). No correlation between FGF-3 amplification and overall survival was noted. The data combine to suggest that FGF-3 is an indicator of aggressiveness of ovarian cancer.

Actuarial Analysis↗
PubMed1993

Primary carcinoma of the fallopian tube--a retrospective analysis of 115 patients. Austrian Cooperative Study Group for Fallopian Tube Carcinoma.

Incidence and prognostic factors of primary carcinoma of the Fallopian tube were studied in a retrospective multi-centre analysis of 115 women during the period 1980 to 1990. Data of 28 departments (university as well as general hospitals) were included in the present study which was designed to evaluate the current diagnosis and treatment of carcinoma of the Fallopian tube in Austria, and to compare the results with those from the literature. Stages were classified according to the modified FIGO-system for ovarian cancer; grading followed the criteria of Hu et al. (1950). The mean age of the patients was 62.5 years. Forty-seven (40.9%) tumours were found to be in stage I, 20 (17.4%) in stage II, 34 (29.6%) in stage III, and 14 (12.1%) in stage IV. In 82 patients, the tumour could be completely removed. The surgical method applied in 95 cases was removal of the uterus, the adnexa, and/or the omentum, or lymph nodes. Postoperatively patients underwent adjuvant therapy which was either irradiation (n = 40; 34.8%), or chemotherapy (n = 49; 42.6%); 26 women (22.6%) had no therapy after operation. The 5-year survival rate for all stages was 36.5%. In stages I and II the 5-year survival was 50.8% compared to 13.6% in stages III and IV. FIGO-stage I and II and a residual tumour less than 2 cm in advanced disease had a prognostically favourable impact, which was proven in univariate as well as multivariate analysis.

Adult↗
PubMed1993

[Primary fallopian tube cancer--an Austrian multicenter study].

Incidence and prognostic factors of primary carcinomas of the Fallopian tubes were studied in a retrospective multi-centre analysis of 81 women during the period of 1980 to 1990. Data from 13 departments (university as well as general hospitals) were included in the present study which was designed to evaluate the state-of-the-art of diagnosis and treatment of carcinoma of the Fallopian tubes in Austria, and to compare the results with those from the literature. Stages were classified according to the modified FIGO-system for ovarian cancer; grading followed the criteria of Hu, Taylor and Hertig. The mean age of the patients was 62.1 years. Thirty-seven (45.7%) tumours were found to be in stage I, sixteen (19.8%) in stage II, nineteen (23.4%) in stage III, and nine (11.1%) tumours in stage IV. In 66 Patients, the tumour could be radically removed. The surgical method applied in 68 cases was removal of the uterus, the adnexa, and/or the omentum, or lymph nodes. Post-operatively, patients underwent an adjuvant therapy which was either irradiation (n = 32; 39.5%), or chemotherapy (n = 34; 42.0%). Fifteen patients had no therapy after operation. The five-year survival rate for stages I and II was 75% compared to 17% in stages III and IV.

Adult↗
PubMed1993

[Energy metabolism of chicks at low environmental temperatures].

The daily energy metabolism of growing chickens for meat production (origin T 82) fed ad libitum was measured from the 5th up to the 65th day of life at environmental temperatures decreasing in the course of development (25, 20, 15, 15, 15, 10, 10, 5 and 5 degrees C, resp.). Further in each period the heat production was measured through a wide range of temperatures (Maximum 40 degrees C to 5 degrees C in steps of 5 K) by 30-minute short time measurements. The mean live weight of the chickens was 75 g at the beginning of the experiment and 3416 g (male) or 2952 g (female) at the end of the experiment. The digestibility of energy and nutrients was independent of the stage of development. On average the total efficiency of utilization of metabolizable energy was 39.2 +/- 4.8% and the partial efficiency of utilization was 69.7 +/- 2.1%. 15-38% of the produced heat, caused by thermoregulation. The thermoneutral temperature decreased in the course of development from 35 to 18 degrees C and in the same way the thermoregulatory heat production decreased from 23 to 12 kJ/kg LW0.75.d.K. In the 2nd period the thermoregulatory heat production was extraordinarily high at an amount of 28 kJ/kg LW0.75.d.K.

Animal Feed↗
PubMed1993

[The effect of the protein level of food on the energy maintenance requirement of growing rats on different feeding regimens].

Male Wistar rats were fed in the live weight range between 70 and 200 g in periods alternately for maintenance and weight gain (semi ad libitum). The diets contained 10, 40 and 70% crude protein, resp., the ambient temperature was 30 degrees C. In agreement with two previous experiments 2 different feed regimes were used. Whereas in the first growth phase (up to about 150 g live weight) the supply of protein was constant for each group, in the second growth phase the protein level was changed between the groups from one period to the other. The energy metabolism on the feeding level of maintenance was measured by indirect calorimetry. At both feeding regimes a dependence of energy maintenance requirement on the protein level of feeding was established. The differences in the maintenance requirement between the 10% and 70% protein level and in the first growth phase also between the 10% and 40% protein level corresponded on average to a growth phase the expected values of which result from the different efficiency of ATP synthesis in the oxidative degradation of nutrients. It follows that--in accordance with the previous findings--the feeding regime does not influence the ratio of energetic utilization of nutrients in the maintenance metabolism of growing rats under the experimental conditions used by us. Further the results of all our studies on the dependence of the energy maintenance requirement of growing rats on the nutrient composition are summarized. We conclude that a dependence on the protein-carbohydrate ratio of the diet according to the different efficiency of ATP synthesis in the protein and carbohydrate catabolism can be reproducibly established by our experimental methods only then, if more than 50% of the energy maintenance requirement are covered from protein energy.

Adenosine Triphosphate↗
PubMed1993

Routine high-dose vitamin A therapy for children hospitalized with measles.

Measles is without specific therapy and remains important globally as a cause of childhood death. In controlled studies, high-dose vitamin A therapy (Hi-VAT)--with 400,000 IU vitamin A--has been demonstrated to markedly reduce measles-associated morbidity and mortality. We performed a retrospective study of the hospital records of 1720 children < 15 years of age who were hospitalized for measles, to determine the extent to which these findings, in research settings, are applicable to the case management of measles under conditions of routine hospital practice. The outcomes were studied of children hospitalized during two non-consecutive 2 year periods (1985-6 and 1989-90). A policy of Hi-VAT for all children hospitalized with measles was started during the intervening period. As compared with the group of children on standard therapy (n = 1061), children receiving Hi-VAT (n = 651) had a shorter hospital stay (mean 10 versus 13 days; P < 0.001), a lower requirement for intensive care (4.3 versus 10.5 per cent; P < 0.001), and a lower death rate (1.6 versus 5 per cent; P < 0.001). No adverse effects of Hi-VAT therapy were observed. We conclude that a policy of high dose oral vitamin A (400,000 IU) supplementation in measles provides benefits which are equivalent to those previously observed only in controlled research trials, that it is highly cost effective, and that it should form part of the routine case management of all children hospitalized with measles.

Administration, Oral↗
PubMed1993

Comparative analysis of the immunoprotective abilities of glycosylated and deglycosylated parainfluenza virus type 3 surface glycoproteins.

The role of carbohydrate moieties on the immunoprotective ability of parainfluenza virus type 3 (PIV-3) haemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins was tested in hamsters. HN and F proteins were purified from detergent-solubilized virus by lentil-lectin affinity chromatography and deglycosylated by treatment with endoglycosidase F (endo F). Immunization of hamsters with either 1 or 5 micrograms of mock-treated (glycosylated) affinity-purified proteins elicited strong haemagglutination inhibition and neutralizing antibody responses 4 weeks after the primary injection. In contrast, titres were significantly lower with endo F-treated (deglycosylated) proteins. However, following the booster doses with at least 5 micrograms of antigen, glycosylated and deglycosylated proteins induced comparable antibody titres. There was no significant difference in the ability of the glycosylated or deglycosylated proteins to protect either the upper or lower respiratory tracts of immunized hamsters against PIV-3 challenge. These results suggest that the carbohydrate moieties of the HN and F proteins are not necessary for eliciting a protective response in hamsters.

Amino Acid Sequence↗