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Biomedical subjects

R C Miller

Publications and source records attributed to R C Miller.

At least 253 records · Page 14Linked to original sources
PubMed1979

Complicated intestinal atresias.

In this group of 45 intestinal atresia patients (duodenum, 16; jejunum, 24; ileum five) at the University of Mississippi Medical Center, individual hospitalizations ranged up to 245 days. Twelve patients required multiple operations, and the overall mortality rate was 22% (ten patients). While the patients with duodenal atresia had the greatest incidence of other congenital anomalies, including Down's syndrome, the patients with jejunal atresia presented with the most challenging surgical problems. Of the 24 jejunal atresia patients, only three had a single, simple area of obstruction. The remainder were complicated by other gastrointestinal lesions (five patients), by multiple areas of atresia (seven patients) including those in one surviving patient with 22 separate atretic segments, and by the Christmas tree deformity (nine patients). Intraoperative management of the complicated atresia should include: 1) grouping of multiple atresias during resection, 2) adequate resection of the dilated proximal atonic loop, 3) end-to-end anastomoses, 4) avoidance of intraluminal catheters, 5) additional resection of a segment of the distal loop in the Christmas tree deformity and 6) consideration of the shish kebab technique for multiple atretic webs. Postoperative management should involve early intravenous nutrition and repeated exploration for continued obstruction.

Abnormalities, Multiple↗
PubMed1979

Effects of uptake inhibitors on responses of sheep coronary arteries to catecholamines and sympathetic nerve stimulation.

1. Transmural stimulation of intrinsic sympathetic nerves and exogenous catecholamines produce beta 1-adrenoceptor mediated relaxant responses in strips of contracted sheep coronary artery. 2. The neuronal uptake inhibitors, metaraminol, cocaine and desipramine and the extraneuronal uptake inhibitor, cortisol, failed to potentiate responses to noradrenaline or sympathetic stimulation; responses to isoprenaline were enhanced by cortisol. 3. Oxytetracycline, which inhibits binding to connective tissue fibres, did not affect responses to noradrenaline or nerve stimulation. 4. 17 beta-Oestradiol, caffeine and U0521 proved to be unsuitable compounds for studying catecholamine inactivation since they non-selectively potentiated responses to noradrenaline and isoprenaline. 5. It is concluded that catecholamine inactivation processes do not modify transmitter function in sheep coronary arteries.

Acetylcholine↗
PubMed1979

Electron microscopic analysis of partially replicated bacteriophage T7 DNA.

Partially replicated bacteriophage T7 DNA was isolated from Escherichia coli infected with UV-irradiated T7 bacteriophage and was analyzed by electron microscopy. The analysis determined the distribution of eye forms and forks in the partially replicated molecules. Eye forms and forks in unit length molecules were aligned with respect to the left end of the T7 genome, and segments were scored for replication in each molecule. The resulting histogram showed that only the left 25 to 30% of the molecules was replicated. Several different origins of DNA replication were used to initiate replication in the UV-irradiated experiments in which 32P-labeled progeny DNA from UV-irradiated phage was annealed with ordered restriction fragments of T7 DNA (K. B. Burck and R. C. Miller, Jr., Proc. Natl. Acad. Sci. U.S.A. 75:6144--6148, 1978). Both analyses support partial-replica hypotheses (N. A. Barricelli and A. H. Doermann, Virology 13:460--476, 1961; Doermann et al., J. Cell. comp. Physiol. 45[Suppl.]:51--74, 1955) as an explanation for the distribution of marker rescue frequencies during cross-reactivation; i.e., replication proceeds in a bidirectional manner from an origin to a site of UV damage, and those regions of the genome which replicate most efficiently are rescued most efficiently by a coinfecting phage. In addition, photoreactivation studies support the hypothesis that thymine dimers are the major UV damage blocking cross-reactivation in the right end of the T7 genome.

DNA Replication↗
PubMed1979

Mixed bacteriophage infection of Escherichia coli: exclusion of superinfecting T4 by T7.

Escherichia coli was infected with T7, then with T4. When the time between the addition of the tow phages was 5 or more minutes, T4 was excluded and most of the infective centres yielded T7 progeny. The DNA of excluded T4 was injected, but it did not replicate nor was it degraded extensively. Transcription of this T4 DNA was largely inhibited, and the transcripts produced were not translated. A variety of T7 amber mutants was examined for the capacity to exclude T4. Amongst the early T7 genes, only the product of gene 1, the T7 RNA polymerase, was essential for T4 exclusion. None of the late genes examined was essential for exclusion.

DNA, Viral↗
PubMed1978

Bilateral primary germ cell testicular tumors: report of four cases and review of the literature.

Bilateral primary germ cell tumors of the testicle are rare. The last comprehensive review of the literature (1955) revealed a 1.6% incidence. However, during the past twenty years, cases have been reported more often, raising the questions of increased frequency due to prolonged survival following surgery and/or roentgen therapy for unilateral tumors. A search of the medical journals during the past two decades fails to show any increased frequency of bilaterality (1.56%). All general combinations of cell types may occur and the tumors may appear simultaneously or sequentially. Successive seminomas are seen more often followed in frequency by concurrent seminomas. Although 50% of the second primaries were diagnosed within five years, 3% of the patients developed the second tumor after 20 years, stressing the need for extended follow-up. Factors affecting the diagnosis, management and prognosis of bilateral testicular tumors are discussed. Four additional cases of bilateral germ cell tumors are described.

Adult↗
PubMed1978

Acute iron intoxication with intestinal infarction.

A fatal case of acute iron intoxication with intestinal infarction is reported, with emphasis on the acute gastrointestinal effects of iron ingestion. The patient demonstrated the progressive necrotizing effects of retained iron on the gastrointestinal tract. Although moderate amounts of iron may be irritating and may produce diarrhea, larger amounts may cause paralytic ileus. Localized concentrations of iron may then exert corrosive effects and cause segmental infarctions and perforations. Emphasis must be given to the purging of iron products from the bowel. Should surgery become necessary because of localized infarction or perforation, we believe that it is advisable to not only thoroughly irrigate the peritoneal cavity but also irrigate the lumen of the bowel so as to remove as much of the remaining iron as possible, lest further areas of necrosis and perforation develop because of continued corrosive effects.

Female↗
PubMed1978

Oncogenic transformation in vitro by the hypoxic cell sensitizer misonidazole.

The hypoxic cell sensitizer Misonidazole (Ro-07-0582) induces oncogenic transformations in the C3H/10T1/2 mouse embryo cell line cultured in vitro. A drug concentration of 0.4 mM applied to aerated cells for 3 or 6 days results in a transformation rate comparable to that observed following an X-ray dose of 1 Gray. A higher drug concentration of 6.0 mM is equivalent to 4 Gy. The combination of Misonidazole and X-rays produces a significant increase in the frequency of transformation over either drug or radiation alone, but the data are equivocal on the question of additivity vs synergism.

Cell Line↗
PubMed1978

Marker rescue and partial replication of bacteriophage T7 DNA.

Experiments reported here show that some UV-irradiated wild-type T7 phage markers can be rescued efficiently by coinfection with T7 amber mutant phage in a permissive host. Other results show that the segments of a UV-irradiated genome that replicate efficiently are those that also are rescued efficiently during a marker rescue experiment. At higher doses, fewer markers are rescued efficiently and fewer segments of the genome replicate efficiently. The results clearly indicate that the probability of marker rescue is correlated with the ability of the DNA containing the marker to replicate. Sucrose density gradient analysis shows that UV irradiation does not produce double-strand scissions in T7 DNA at doses used here. Therefore, the partial replication and rescue of markers from the left end of the genome is not due simply to injection of only the left end of the T7 DNA.

Chromosome Mapping↗
PubMed1978

Catecholamine uptake by isolated coronary arteries and atria of the kitten.

Kitten coronary arteries and atria incubated with [3H]-(-)-noradrenaline or [3H]-(+/-)-isoprenaline showed concentration- and temperature-dependent accumulation of amines (unchanged and/or as metabolites). In addition, coronary arteries incubated with [3H]-(+/-)-isoprenaline showed temperature-insensitive amine accumulation due to binding to connective tissue fibres. 2 With low concentrations of [3H]-(-)-noradrenaline (20 ng/ml) accumulation of radioactivity in both tissues was neuronal since it was reduced by desipramine, metaraminol or cocaine but not by the extraneuronal inhibitor, cortisol. 3 In coronary arteries incubated with [3H]-(+/-)-isoprenaline (5 microgram/ml) for 1 or 10 min, uptake was extraneuronal since it was inhibited by cortisol, 17beta-oestradiol or phenoxybenzamine. 4 Atria incubated with (+/-)-isoprenaline (5 to 1000 microgram/ml) showed non-neuronal, biphasic accumulation of amine. There was a high capacity, low affinity initial uptake process (apparent Km 136 micron) which was resistant to steroidal extraneuronal uptake inhibitors but which could be abolished by phenoxybenzamine. A slower uptake occurred after 2 min which was sensitive to steroidal and other extraneuronal uptake inhibitors. 5 Inhibition of uptake processes did not alter sensitivity of coronary arteries to dilator effects of catecholamines. However, experiments with extraneuronal uptake inhibitors were limited by the relaxant effects of cortisol and 17beta-oestradiol themselves. 6 In atria inhibition of neuronal uptake by desipramine or cocaine led to supersensitivity to (-)-noradrenaline but not to (-)-adrenaline or (+/-)-isoprenaline. Chronotropic responses to (-)-noradrenaline were increased five fold and inotropic responses three fold.

Animals↗
PubMed1978

The structure and maturation of intermediates in bacteriophage T7 DNA replication.

Concatemeric DNA from T7-infected cells consists of phage genomes in a linear head-to-tail arrangement. Adjacent genomes within a concatemer overlap for the length of the terminal repetition. Fast-sedimenting T7 DNA contains single-stranded regions at roughly unit-lentth intervals but these interruptions are heterogeneously distributed and do not occur at the genetic termini. Mutations in either bacteriophage genes 9, 18, or 19 (required for DNA maturation and packaging) lead to the synthesis and persistence of DNA with fewer interruptions than normal.

Base Sequence↗
PubMed1978

Acute and long-term cytogenetic effects of childhood cancer chemotherapy and radiotherapy.

Approximately 30 banded karyotypes per subject from the lymphocytes of 66 childhood cancer patients and 14 noncancer control subjects have been analyzed in an attempt to gauge the late effects of anticancer chemotherapy and chemotherapy plus radiotherapy on the genetic material, i.e., the chromosomes. The frequencies (f) of aberrant cells were: f = 1/306 among cells from noncancer controls; f = 1/377 from cancer patients prior to therapy, f = 1/15 from patients currently on chemotherapy; and f = 1/32 from posttherapy patients (range, 3 months to 22 years poattherapy). The frequency of chromosomally aberrant cells did not appear to change with time among posttherapy patients, and the majority of aberrations detected in subjects from this group were balanced rearrangements. This was not the case for the on-therapy group where unbalanced rearrangements and unstable aberrations predominated.

Antineoplastic Agents↗
PubMed1978

Evaluation of the co-immobilized hexokinase/glucose-6-phosphate dehydrogenase method for glucose, as adapted to the Technicon SMAC.

We assessed the analytical performance of the co-immobilized hexokinase (EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) method for D-glucose analysis on the Technicon SMAC. The enzyme-containing coils were usable for one month, or 12 000 tests. Bilirubin, hemoglobin, lipemia, creatinine, uric acid, citric acid, and ascorbic acid did not interfere. Results with this method were compared to those by the National Glucose Reference Method. The upper limits of the total error estimate (a combination of random and systematic errors) were 76, 74, and 125 mg/liter at concentrations of 500, 1200, and 3000 mg/liter, respectively. The error estimates were less than allowable errors based on medical usefulness; thus the method was judged to perform acceptably with respect to the Reference Method. We also present performance data for the routine SMAC glucose oxidase (EC 1.1.3.4)/Peroxidase (EC 1.11.1.7) 3-methyl-2-benzothianolinone hydrazone-N,N-dimethylaniline method, the direct hexokinase method with the Du Pont aca, and the glucose oxidase oxygen-rate method with the Beckman Glucose Analyzer.

Autoanalysis↗