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Biomedical subjects

H E Jacob

Publications and source records attributed to H E Jacob.

At least 19 recordsLinked to original sources
PubMed1997

One school's experience with the development of an oncology nurse practitioner curriculum.

PURPOSE/OBJECTIVES: To describe the foundational work and implementation of a nurse practitioner (NP) curriculum geared toward oncology nurses. The study is selective (not comprehensive) and reflective of one school's experience. DATA SOURCE: Journal articles, curriculum guidelines, anecdotal experience, and interviews. DATA SYNTHESIS: The NP is used more frequently in oncology, both as a clinician and for other aspects of advanced practice nursing. NPs must be prepared to fulfill graduate criteria as outlined by definitive sources for curriculum development. CONCLUSIONS: Schools must work with employers, graduates, and patients in conducting outcome evaluations to measure safety issues and role effectiveness of oncology NPs (ONPs), as well as fulfillment of all aspects of the advanced nursing practice role. IMPLICATIONS FOR NURSING PRACTICE: If healthcare employers continue to rely heavily on the use of ONPs, schools of nursing must be prepared to graduate safe clinicians, experts in oncology, and advanced practice nurses, all combined into one graduate. This difficult task requires evaluation of current practices.

Certification↗
PubMed1994

Chemotherapy for cranial base tumors.

The tumors I will discuss in this chapter on chemotherapy will be ethesioneuroblastoma, salivary gland tumors, chordoma and nasopharyngeal carcinoma. Due basically to the rarity of these lesions, with the exception of nasopharyngeal carcinoma, there have been no multi-institutional studies of chemotherapy use reported in the literature. As a result, there is no clear-cut consensus on the standard of care as it relates to chemotherapy for these tumors. As with most authors who have previously reviewed these tumor types, I believe it is important for us to propose protocols of therapy and test these in arenas where we can accumulate enough patients for meaningful results. In this way, we can test the apparently active agents and combinations in relapsed or extensive disease. We might also begin to explore concurrent therapy (i.e., concurrent radiation and chemotherapy after the surgical procedure, for example).

Antineoplastic Agents↗
PubMed1990

Kinetics of secondary metabolite formation by wild type and mutant strains of Streptomyces griseus.

In a particle containing medium, the kinetics of formation of secondary metabolites of a Streptomyces wild type and a mutant strain were determined by spectrophotometric measurements of the anthracyclinone pigments and by the analysis of antibiotic activity of the substances produced. The results were related to the physiological state of the culture derived from the oxygen supply. The total cultivation time was about 400 hours. The production of secondary metabolites started at the end of the logarithmic growth phase (after about 30 hours). During the following cultivation remarkable differences between the two strains regarding the formation of pigments and antibiotics occurred. In the wild type strain producing daunomycinone glycosides and related compounds with antibiotic activity, these antibiotics are active as inhibitors (negative feedback). Therefore, at a certain concentration of antibiotics, the de-novo formation of anthracycline molecules was impaired. In the mutant strain, as the result of a genetic change, the secondary metabolite production was shifted to nonglycosylated compounds. The production of these substances is not influenced by feedback inhibition as in the case of the wild type strain. From that reason the amount of pigment increased slightly throughout the course of the experiment. Under our experimental conditions the measurement of oxygen supply was a suitable indicator of the physiological state of culture.

Antibiotics, Antineoplastic↗
PubMed1983

Autolysis of Thermoactinomyces vulgaris spores lacking carbon dioxide during germination.

Ultrathin sections of early germinating endospores of Thermoactinomyces vulgaris were studied by electron microscope. Only spores aerated with an air-CO2 mixture (5% CO2) grow out, while spores aerated with air (0.03% CO2) lyse by the 25th min of inoculation. The lysis is due to progressive, unlimited degradation of the spore integuments and a lack of cell wall formation around the spore protoplast. The requirement of CO2 for outgrowth could not be replaced by oxaloacetate. CO2 seems to be needed to energize the dormant cytoplasmic membrane of the spore to render it capable of initiating active transport processes and of synthesizing the germ cell wall.

Bacteriolysis↗
PubMed1983

[Effects of 5-bromouracil and 5-bromodeoxyuridine in combination with 8-aza-adenine on the UV sensitivity of bacteria].

The presence of 5-bromouracil (BU) as well as 5-bromo-2-deoxyuridine (BUdR) in the cultivation media of bacteria results in the distinct increase of UV sensitivity. With the nucleic acid base analogue 8-azaadenine (8-AA) a similar effect was confirmed, however, not so pronounced. In the experiments reported here the combined action of BU or BUdR and 8-AA on Escherichia coli, Proteus mirabilis, Bacillus subtilis and Bacillus cereus was investigated. The sensitization effect of BUdR does not increase if 8-AA is present additionally during cultivation. On the contrary, a decrease of sensibilization occurs. This result may be caused by the protective effect of the adenine derivative against UV irradiation, if it is present in the cell, but not incorporated into the DNA.

Adenine↗
PubMed1982

[Physiological and cell biological characterization of the protease producer Thermoactinomyces vulgaris during prolonged culture in a stirred fermenter].

The physiological behaviour of Thermoactinomyces vulgaris - producing a thermostable serine-protease - was analyzed during fermentation. During 38 h the consumption of nutrients and oxygen as well as the rates of macromolecular and protease synthesis were measured. The morphological and ultrastructural changes of the mycelia were also studied. The mycelia grew exponentially for about 5 hours. After a short lag and a second slower growth phase, growth continued about linearly until the end, as was indicated by a constant rate of incorporation of labelled thymidine. However, at the same time a changing portion of hyphae - up to 45% - underwent lysis. According to the changing ratio of growing and lysing material, regarding the physiological activity of the culture the fermentation process could be divided into 4 periods. The formation of the protease started at the transition to the slow growth phase and continued linearly. The ability to produce the protease was attributed to a mycelium being formed after the shift down caused by limitation of supply of utilizable nitrogen compounds. The end of protease production 10 h later was correlated to a drastic decrease of the respiratory activity of the mycelia, probably caused by exhaustion of easily utilizable carbohydrates.

Amino Acids↗
PubMed1981

Microbiological implications of electric field effects. II. Inactivation of yeast cells and repair of their cell envelope.

The inactivation of yeast cells in different growth phases by an electric field pulse was investigated. Cells of Saccharomyces cerevisiae in the logarithmic growth phase were found to be much more sensitive with respect to an electric discharge than those in the stationary phase. The influence of the electric field pulse characteristics on the inactivation as well as possible secondary effects were studied. The polyene antibiotic perhydrohexafungin (PHF) is used as a tool to sense defects in the yeast cell envelope brought about by electric field action. The repair kinetics of these defects was followed after the impulse. At least two repair stages can be distinguished, a fast one in the second range and a slower one which takes place after plating the cells on a nutrient medium. The obtained results are discussed in connection with current theories of reversible dielectric breakdown in biological membrane systems.

Antifungal Agents↗
PubMed1981

Microbiological implications of electric field effects. III. Stimulation of yeast protoplast fusion by electric field pulses.

Prototrophic colonies could be selected on minimal medium after mixing of protoplasts from diauxotrophic mutants of the yeasts Saccharomycopsis lipolytica and/or Lodderomyces elongisporus and treatment with polyethylene glycol (PEG) in the presence of calcium chloride. This is the result of protoplast fusion and complementation of auxotrophic deficiencies. Under identical conditions an electric field pulse in the mus-range applied via an electric discharge to the protoplast-PEG mixture resulted in a drastic enhancement of the protoplast fusion rate. The presence of polyethylene glycol was demonstrated to be a prerequisite for fusion in this case, too. The frequency of hybrid formation detected a prototrophic colonies could be increased in the case of intraspecific fusion at initial electric field strengths between 2.5 and 5 kV . cm-1. The application of an electric field pulse of proper strength and duration to a yeast protoplast suspension turned out to be a more effective tool in production of fusion products that conventional methods. Large numbers of parasexual hybrids for different selection programmes in yeast genetics and for industrial purpose may be delivered by this technique.

Electricity↗
PubMed1981

[Diarrhea in young calves. 4. Redox potential of the gastrointestinal tract of clinically healthy calves, and calves with spontaneous diarrhea, experimental Escherichia coli infection, and cyclophosphamide treatment].

The redox potential (ROP) dropped strongly in a calf, from two hours after birth to 48 hours of age. The drop in the colon was more strongly pronounced than that in the small intestine. -The Eh values recorded throughout the small intestine of clinically intact calves, aged between four and ten days, were more negative than those in the stomach. The most negative ROP values, which differed with significance from those of all proximal gastro-intestinal sections, were recorded from the caecum. -Intracolonic negativation of ROP in calves, during the first hours of life, must be attributed to progressing germ population. The same relationship is borne out clearly by a pronounced rise in anaerobic germ count accompanied by significant ROP negativation in the colon. -Growing age was accompanied by drastic change in ROP values throughout the gastro-intestinal tract. Calves aged between six and nine weeks were compared to animals aged between four and ten days. ROP values in stomach, proximal and distal jejunum as well as in the ileum of the former group were negative with significance, whereas ROP values in the caecum and colon of the same group were more positive. -Animals with diarrhoea exhibited significant ROP deviations only in the ileum. They were more negative, as compared to clinically intact calves aged between four and ten days. Pathophysiological intestinal disorders which could be measured via ROP were found to play no role at all in the genesis and course of diarrhoea of calf. -No pronounced gastro-intestinal ROP deviations were exhibited by calves with experimentally induced Escherichia coli infection and manifest coli dysentery nor by animals which received cyclophosphamide treatment.

Animals↗
PubMed1981

[Redox potential of the gastrointestinal tract of swine of different ages].

The redox potential (ROP) was found to undergo negativation in all gastro-intestinal sections of piglets, from the time of birth to the age of three days. Negativation was relatively low in the small intestine, but it accounted for more than 300 mV in stomach and colon. ROP values recorded from stomach and rectum of weaned piglets were more negative with significance than those established from animals before weaning. ROP, as an important environmental factor in the gastro-intestinal tract, did not undergo significant change due to weaning which might support any conclusion as to pathogenesis of coli-enterotoxaemia, in spite of the implied change of feeding and keeping conditions. ROP in store pigs was found to be more or less one and the same, except for more positive values in the proximal jejunum, with most negative values being recordable from the stomach. Progressing age was found to be accompanied by sizeable ROP change in the gastro-intestinal tract of swine. ROP values in the distal jejunum and ileum of sows were more negative with significance than those recorded from store pigs, but values were more positive in the colonic cone and rectum. Unambiguous ROP negativation in the proximal and distal jejunum and ileum as well as in the gastro-intestinal tract of sows was accompanied only by moderate rise in overall anaerobic germ count. ROP values recorded from the colonic cone and rectum, where highest germ counts were detectable, were more positive than those recorded from any other intestinal section. Hence, gastro-intestinal ROP of sows is, probably, not controlled by metabolism of the germ flora.

Aging↗
PubMed1980

[Copper II complexes of N-heterocyclic formylisothiosemicarbazones with antimicrobial and beta-lactamase inhibitory activity].

The synthesis of copper(III)-complexes from quinoline-2- or quinoxaline-2-aldehyde-isothiosemicarbazones in pyridine and the elucidation of their structure are described. Some of the new substances exhibit an inhibitory action on growth of gram-positive bacteria, especially Bacillus subtilis (ATCC 6633), furthermore in vitro the beta-lactamase I action is inhibited. Using penicillin-resistant Staphylococci as test strains a strong penicillin-synergistic action was discovered.

Anti-Bacterial Agents↗
PubMed1979

[Photodynamic effect of quinacrine on bacteria].

The acridine dye quinacrine (QA) was tested with regard to the photodynamic action on bacteria (Proteus mirabilis, Escherichia coli). The absorption maximum of the yellow dye QA ist in contrary to the photodynamically active dyes methylene blue (MB) and thiopyronine (TP) situated in the short wave region of the visible spectrum. Using for illumination a common light source--they have in general a weak emission in the short wave region--relatively high concentrations of QA are necessary for photodynamic action, and the difference between photodynamic inactivation and toxic effect is small. Using that light source XBO 500 with nearly equal emission in the range from 400 to 700 nm, a distinct photodynamic action of QA results. Comparing the photodynamic action of QA with those of MB and TP, QA has a low photodynamic effect, and the kinetics of inactivation of bacteria with QA is completely different from those obtained with the dyes MB and TP.

Escherichia coli↗
PubMed1976

Characterization of the antibiotic resistance plasmid ERL1 from Streptococcus pyogenes.

The streptococcal plasmid ERL1 determining inducible resistance to erythromycin, lincomycin, and staphylomycin S was isolated by dye-buoyant density centrifugation and shown to have a molecular weight of about 17.5 Mdal, as revealed by sedimentation through neutral sucrose gradients. In SM60 cells entering the stationary phase its covalently closed circular form was present to the extent of 5 copies per chromosomal genome equivalent, ERL1 was subject to the DNA restriction and modification mechanism discovered in strain 56188. It did not appear to exercise restriction of phage DNA but mediated a partial release of the restricted growth of A25.

DNA, Bacterial↗