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Biomedical subjects

C Cramer

Publications and source records attributed to C Cramer.

50 records · Page 3Linked to original sources
PubMed1985

Actinlike material in Pseudomonas aeruginosa.

Actinlike material was obtained from disrupted Pseudomonas aeruginosa cells by a modification of the method of Hancock and Nikaido (J. Bacteriol. 136:381-390) for isolating outer membrane vesicles. Pelleted membranes were dissolved in Laemmli sample buffer and electrophoresed in parallel lanes with purified rabbit skeletal muscle actin. The bacterial preparation migrated similarly to rabbit skeletal muscle actin. A doublet band was detectable by affinity-purified antiactin antibody in a passive transfer immunoblot. Molecular weight of the actinlike protein doublet was 60,000 to 63,000 as determined by linear regression analysis of Bio-Rad low-molecular-weight standards run on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Transmission electron microscopy of the actinlike material in high salt concentrations revealed 10- to 14-nm filaments of various lengths. Despite its ability to form filaments and to react with a polyclonal rabbit antiactin antibody, the bacterial filaments did not bind the S-1 fragment of heavy meromyosin.

Actins↗
PubMed1985

Pseudomonas aeruginosa induced ocular infection. A histological comparison of two bacterial strains of different virulence.

The purpose of this study was to compare and characterize histopathologically the virulence of two bacterial strains in a naturally susceptible animal host. One of the strains Pseudomonas aeruginosa ATCC 19660, routinely used in this laboratory, produces endopthalmitis and phthisis bulbi in C57BL/6 mice within 3-4 weeks. The other bacterial strain, a clinical isolate from a 70-year-old patient with Pseudomonas corneal infection was found to be less virulent in the patient and thus was examined for virulence in the susceptible mouse model. The strain also proved to be less virulent in the normally susceptible mouse when compared with ATCC 19660. In general, when comparing the histopathological response of the mice to the two bacterial strains, it was found that in contrast to ATCC 19660, fewer polymorphonuclear neutrophils migrated into the cornea at 24-72 h, endothelial and epithelial necrosis was delayed, few free bacteria were observed in the cornea and animals recovered corneal clarity by 21-25 days following infection.

Animals↗
PubMed1979

Regulatory mutants at the his1 locus of yeast.

The his1 gene in Saccharomyces cerevisiae codes for phosphoribosyl transferase, an allosteric enzyme that catalyzes the initial step in histidine biosynthesis. Mutants that specifically alter the feedback regulatory function were isolated by selecting his1 prototrophic revertants that overproduce and excrete histidine. The prototrophs were obtained from diploids homoallelic for his1--7 and heterozygous for the flanking markers thr3 and arg6. Among six independently derived mutant isolates, three distinct levels of histidine excretion were detected. The mutants were shown to be second-site alterations mapping at the his1 locus by recovery of the original auxotrophic parental alleles. The double mutants, HIS1--7e, are dominant with respect to catalytic function but recessive in regulatory function. When removed from this his1--7 background, the mutant regulatory site (HIS1-e) still confers prototrophy but not histidine excretion. To yield the excretion phenotype, the primary and altered secondary sites are required in cis array. Differences in histidine excretion levels correlate with resistance to the histidine analogue, triazoalanine.

Alleles↗
PubMed1976

Effect of melatonin on the basal and stimulated gonadotropin levels in normal men and postmenopausal women.

The effect of melatonin on LH and FSH secretion in basal conditions and after stimulation with synthetic LHRH was studied in 3 volunteer normal men and 3 women two to five years after menopause. During the first three days of study, blood samples were obtained at 8 AM. On the second day, an iv injection of 50 mug LHRH was performed; on the third day, 2 ml of 0.9% saline were injected. In both cases, blood samples were obtained 30 and 60 minutes after the injection. On the fourth day, the subjects began melatonin (10 mg daily im for 13 days). Blood samples at 8 AM were obtained after 5, 11, and 13 days of administration of the drug. On days 5 and 11 of the treatment, iv injections of 50 mug LHRH were performed and on day 13 an iv injection of saline 0.9% was given. Blood samples were obtained 30 and 60 minutes after each injection. In each sample LH and FSH levels were determined by radioimmunoassay. Melatonin treatment did not cause any significant change in basal or post-stimulation LH and FSH levels either in men or in post-menopausal women. These results do not support previous findings of an insults do not support previous findings of an inhibitory effect of melatonin on gonadotropin secretion, even with the same dose as the one used in this study. Further studies with higher doses of melatonin are needed to clarify the action of this drug on gonadotropin secretion.

Adult↗
PubMedDate not supplied

Oscillatory corticothalamic response to somatosensory input.

We construct a model of the thalamocortical feedback loop using the Random Neural Network model to provide a theoretical explanation for cortical and thalamic damped rapid (circa 60-100 Hz) oscillations which have been observed in lightly anesthesized rats with somatosensory input Nicolelis (1997). Experimental data corroborates the choice of model parameter settings. Model predictions indicate that positive feedback loops and large signaling delays within cortex significantly determine the oscillatory phenomenon and its duration (i.e. its decay), while positive feedback from cortex to thalamus is needed to exhibit oscillations in thalamus.

Animals↗
PubMedDate not supplied

Caring for elderly patients who have paranoia.

Caring for patients with paranoia presents unique challenges. As increasing numbers of potentially paranoid patients are treated, radiologic technologists must understand techniques that increase patient trust and decrease suspiciousness. Understanding the perceived vulnerability of patients with paranoia and implementing appropriate strategies facilitate trust and are key to providing quality care.

Aged↗
PubMedDate not supplied

Prognostic value of preoperative serum levels of CEA, CA 19-9 and CA 72-4 in gastric carcinoma.

UNLABELLED: We studied the relevance of CEA, CA 19-9, CA 72-4 and the common classical prognostic factors (age, sex, tumor infiltration, N-classification, staging, grading and Lauren classification) in gastric carcinoma. PATIENTS AND METHODS: Survival function estimates were calculated according the method to Kaplan-Meier. The patients were separated into two groups according to preoperative marker levels. Fixing specificity at 100% for healthy people, cut off levels were calculated. Survival curve differences were assessed using the log-rank-test. Multivariate Cox proportional hazards regression analysis was performed. The mantel-Haenszel method was used to assess the 2-year survival rate of patients with gastric carcinoma and high versus low levels of tumor-associated antigens adjusted to tumor stages. The study was performed on the frozen sera (stored at -80 degrees C) of 103 patients with histologically proven gastric carcinoma. RESULTS: The tumor stage (log-rank chi-square = 55.9; P < 0.0001) represents the best prognostic factor besides preoperative values of CA 19-9 (log-rank chi-square = 13.9; P < 0.001) and CEA (log-rank chi-square = 12.2; P < 0.001). CA 72.4 shows a log-rank chi-square of 6.9 (P < 0.01). We found no statistically significant correlation between survival and sex, tumor grade and Lauren classification. The importance of different parameters in providing additional prognostic information was evaluated by multivariate analysis. Only patients after curative surgical intervention (n = 55, R0) were considered. Cox proportional hazards regression analysis yielded an adjusted relative risk of 2.4 in patients with a preoperative CEA concentrations > or = 4 ng/mL vs. < 4 ng/mL, of 2.8 in patients with a preoperative CA 19-9 concentration > or = 60 U/mL vs. < CA 19-9 and of 1.8 for stage III/IV vs. stage I/II (P < 0.05). For CEA the 2-year survival rates in the group of patients with preoperative serum concentrations > or = 4 ng/mL versus < 4 ng/mL and stadium III/IV were 14% versus 29% and in stadium I/II 50% versus 83% (P < 0.05). For CA 19-9 the 2-years survival rates in the group of patients with preoperative serum concentrations > or = 60 U/mL versus < 60 U/mL and stadium III/IV were 14% versus 28% and in stadium I/II 40% versus 83% (P < 0.05). CONCLUSION: The postoperative R-classification and the tumor stage represent the best prognostic information besides the preoperative values of CA 19-9 or CEA, respectively. The predictive information provided by preoperative CEA and CA 19-9 serum levels is additional to that obtained from other factors investigated.

Antigens, Tumor-Associated, Carbohydrate↗