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Biomedical subjects

S Henry

Publications and source records attributed to S Henry.

At least 109 records · Page 6Linked to original sources
PubMed1988

Profile of the breast center: one year's experience.

The Grant Regional Breast Center (GRBC) has proven to be an effective means to offer radiologic breast exam. Not only has the service been very well received by patients but it has also shown a profit for the institution. The numbers are too small to show that there has been an increase in early screening. The numbers do suggest, however, that there has been an increased access to screening. Hopefully, this increased access and awareness will lead to increased early detection and increased long-term survival.

Breast Neoplasms↗
PubMed1987

Evidence for two distinct forms of native glutamic acid decarboxylase in rat brain soluble extract: an immunoblotting study.

Immunoblots of the soluble proteins from a rat brain high-speed supernatant dissociated under reducing conditions showed two monomers (molecular weights, 59,000 and 62,000 +/- 2,000) immunolabeled by a glutamic acid decarboxylase (GAD) antiserum. In this extract, a GAD monoclonal antibody trapped the same two monomers, thus confirming that they are both constitutive subunits of GAD. Without treatment under reducing conditions, two additional bands were stained by immunoblotting. Their molecular weights were estimated to be 115,000 and 122,000 +/- 5,000. These results demonstrate the presence, in rat brain soluble extract, of two distinct forms of native GAD. They further support our previous hypothesis that each form is composed by the homodimeric association of each constitutive subunit through disulfide bridges.

Animals↗
PubMed1987

Removable, adjustable and reusable implants for stereotactic interstitial radiosurgery of brain tumors.

Sixty primary brain tumors (gliomas) were treated by interstitial radiosurgery using 192Ir according to a protocol based on the size of the tumor. In all cases, the radioactive wires were left in place for periods ranging from 5 to 10 days, according to dosimetry calculations, and then removed, which was made possible by the use of removable implants. The stainless steel tubes are occluded on their inner side and adjustable in length depending on the depth of the tumor, and are introduced through screws inserted into the skull in an array depending on the preliminary dosimetry. The tubes were afterloaded with 192Ir and removed at the end of the calculated time. Forty-six patients (18 low-grade and 28 malignant gliomas) were treated using this method. One small hematoma was evacuated and no sepsis occurred.

Brachytherapy↗
PubMed1987

Combined (thalamotomy and stimulation) stereotactic surgery of the VIM thalamic nucleus for bilateral Parkinson disease.

Stereotactic thalamotomy of the thalamic nucleus ventralis intermedius (VIM) is routinely used for movement disorders. During this procedure, it has been observed that high-frequency (100 Hz) stimulation of VIM was able to stop the extrapyramidal tremor. In patients with bilateral tremor of extrapyramidal origin, who were resistant to drug therapy, the therapeutic protocol associated (1) a radiofrequency VIM thalamotomy for the most disabled side, and (2) a continuous VIM stimulation for the other side using stereotactically implanted electrodes, connected to subcutaneous stimulators. VIM thalamotomy relieved the tremor in all operated cases. Side effects were mild and regressive. VIM stimulation strongly decreased the tremor but failed to suppress it as completely as thalamotomy did. This was due in part to the fact that programmable stimulator frequency rate is limited to 130 Hz, while it appeared that the optimal stimulation frequency was 200 Hz. This therapeutic protocol appears to be of interest for patients with bilateral extrapyramidal movement disorders.

Electric Stimulation Therapy↗
PubMed1986

Fatty acid degradation in Caulobacter crescentus.

Fatty acid degradation was investigated in Caulobacter crescentus, a bacterium that exhibits membrane-mediated differentiation events. Two strains of C. crescentus were shown to utilize oleic acid as sole carbon source. Five enzymes of the fatty acid beta-oxidation pathway, acyl-coenzyme A (CoA) synthase, crotonase, thiolase, beta-hydroxyacyl-CoA dehydrogenase, and acyl-CoA dehydrogenase, were identified. The activities of these enzymes were significantly higher in C. crescentus than the fully induced levels observed in Escherichia coli. Growth in glucose or glucose plus oleic acid decreased fatty acid uptake and lowered the specific activity of the enzymes involved in beta-oxidation by 2- to 3-fold, in contrast to the 50-fold glucose repression found in E. coli. The mild glucose repression of the acyl-CoA synthase was reversed by exogenous dibutyryl cyclic AMP. Acyl-CoA synthase activity was shown to be the same in oleic acid-grown cells and in cells grown in the presence of succinate, a carbon source not affected by catabolite repression. Thus, fatty acid degradation by the beta-oxidation pathway is constitutive in C. crescentus and is only mildly affected by growth in the presence of glucose. Tn5 insertion mutants unable to form colonies when oleic acid was the sole carbon source were isolated. However, these mutants efficiently transported fatty acids and had beta-oxidation enzyme levels comparable with that of the wild type. Our inability to obtain fatty acid degradation mutants after a wide search, coupled with the high constitutive levels of the beta-oxidation enzymes, suggest that fatty acid turnover, as has proven to be the case fatty acid biosynthesis, might play an essential role in membrane biogenesis and cell cycle events in C. crescentus.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1985

Erythrocyte depletion of ABO-incompatible bone marrow.

Bone marrow transplantation results in the infusion of 150 to 360 ml of erythrocytes. While this poses no problem to a recipient of marrow from an ABO-compatible donor, it clearly represents a serious risk of intravascular hemolysis for the recipient of an ABO-incompatible marrow. Thus, there is a need for removing incompatible erythrocytes from the marrow preparation. We removed erythrocytes from the marrow preparations by automated centrifugation. The erythrocyte-depleted marrow (EDM) contained a mean of 5 ml erythrocytes, representing an average reduction of 98%. The mean mononuclear cell recovery was 88%, resulting in a mean infusion of 0.6 X 10(8) cells/Kg of recipient's body weight in a final average volume of 155 ml. EDM was infused into 22 ABO-incompatible marrow recipients (21 patients with hematologic malignancies and one patient with aplastic anemia) without clinical evidence of hemolysis. The isohemagglutinin titers of recipients ranged from 4 to 4096 and were not lowered prior to infusion. Engraftment (i.e., recovery of peripheral leukocyte and platelet counts) and incidence of graft versus host disease were similar to those observed in recipients of ABO-compatible marrow transplantation. Erythrocyte engraftment was significantly delayed in only one patient who had a high isohemagglutinin titer. The post-transplantation red cell requirement was increased in EDM recipients: 9 units compared to 6 units in ABO-compatible bone marrow transplanted patients with neither hemolysis nor interference with successful engraftment.

ABO Blood-Group System↗
PubMed1984

Caulobacter crescentus fatty acid-dependent cell cycle mutant.

A fatty acid auxotroph of Caulobacter crescentus, AE6001, which displays a strict requirement for unsaturated fatty acids to grow on glucose as the carbon source has been isolated. Starvation of AE6001 for unsaturated fatty acids resulted in a block in the cell cycle. Starved cultures accumulated at the predivisional cell stage after a round of DNA replication had been completed and after a flagellum had been assembled at the pole of the cell. Cell division and cell growth failed to occur probably because the mutant was unable to synthesize a membrane. An analysis of double mutants containing the fatB503 allele and other mutations in membrane biogenesis demonstrated that the cell cycle of AE6001 blocked at a homeostatic state. The addition of oleic acid to starved cultures permitted cell division and the initiation of a new round of DNA replication. The coincident block in both the initiation of DNA replication and membrane assembly, exhibited by starved cultures of this mutant, suggests that the fatB503 gene product may be involved in the coordination of these events.

Bacteria↗
PubMed1984

Genetic analysis and characterization of a Caulobacter crescentus mutant defective in membrane biogenesis.

A mutant of Caulobacter crescentus has been isolated which has an auxotrophic requirement for unsaturated fatty acids or biotin for growth on medium containing glucose as the carbon source. This mutant exhibits a pleiotropic phenotype which includes (i) the auxotrophic requirement, (ii) cell death in cultures attempting to grow on glucose in the absence of fatty acids or biotin, and (iii) a major change in the outer membrane protein composition before cell death. This genetic lesion did not appear to affect directly a fatty acid biosynthetic reaction because fatty acid and phospholipid syntheses were found to continue in the absence of supplement. Oleic acid repressed fatty acid biosynthesis and induced fatty acid degradation in the wild-type parent, AE5000 . The mutant strain, AE6000 , was altered in both of these regulatory functions. The AE6000 mutant also showed specific inhibition of the synthesis of outer membrane and flagellar proteins. Total phospholipid, DNA, RNA, and protein syntheses were unaffected. The multiple phenotypes of the AE6000 mutant were found to cosegregate and to map between hclA and lacA on the C. crescentus chromosome. The defect in this mutant appears to be associated with a regulatory function in membrane biogenesis and provides evidence for a direct coordination of membrane protein synthesis and lipid metabolism in C. crescentus.

Bacteria↗
PubMed1984

Ethanol-ascorbate interrelationship in acute and chronic alcoholism in the guinea pig.

The effects of low (200 ppm) and of high (2000 ppm) ascorbic acid, in a nutritionally adequate diet, on blood ethanol levels have been studied in permanently carotid-cannulated, ethanol-infused, unanesthetized guinea pigs. In the acute study, the postinfusion rate of ethanol decline in the blood of animals treated with ascorbic acid was significantly higher when compared with animals treated with fructose, and the rate in the two treated groups was significantly higher than in untreated controls. In the chronic study, animals were infused with sublethal doses of ethanol (30% of the total caloric intake) for 8 weeks. Blood ethanol levels monitored throughout this period showed, at 3 hr postinfusion, a lower concentration in the group on a high ascorbic acid diet. Both experimental groups receiving ethanol lost significantly more body weight in the second week of dieting; but, while the group on high ascorbic acid regained weight steadily thereafter, the group on low ascorbic acid was still 50 g below the controls at the end of the experiment. Liver, kidney, and adrenal ascorbic acid concentrations were lower in the ethanol-treated groups compared to controls. Examination of the liver revealed more fatty metamorphosis or steatosis in the low ascorbic acid group, but there was no evidence of liver fibrosis or cirrhosis. These results demonstrate the feasibility of utilizing the guinea pig for the study of the biochemical and morphological sequelae of alcoholism. They further support the contention that a diet which is nutritionally adequate may no longer be so in the presence of high ethanol intake, and that supplemental vitamin C ingestion may afford protection against ethanol toxicity.

Adrenal Glands↗
PubMed1983

Bacteremia due to Fusobacterium species.

Twenty-six patients were identified as having bacteremia with Fusobacterium species over a five-year period at Boston City Hospital. They represented 0.9 percent of bacteremic patients and were equally divided as to sex. Bacteremia with Fusobacterium occurred primarily in young adults and in patients over 60 years of age and was not observed in children. In 16 patients (62 percent), Fusobacterium was the only blood culture isolate. The most common primary foci of infection were the female genital tract, the upper respiratory tract, the oral cavity, and the lower respiratory tract. Five patients had primary foci of infection that were initially occult. Three of these patients were found to have unappreciated oral and pharyngeal lesions, and one had a liver abscess; no primary infection was established in the remaining patient. Shock related to bacteremia developed in six patients (23 percent), four of whom had Fusobacterium species as the only blood culture isolate. Death occurred in three patients (12 percent), all of whom were over 60 years old. Metastatic infection occurred in only one patient in whom hematogenous osteomyelitis developed. Postpartum fusobacterial bacteremia was uniformly benign. Evaluation of bacteremia with Fusobacterium species in nonpostpartum patients, without an overt focus of infection, should be directed to a search for occult abscess, especially of the upper respiratory tract and oral cavity.

Adolescent↗
PubMed1982

Synthesis and utilization of fatty acids by wild-type and fatty acid auxotrophs of Caulobacter crescentus.

The fatty acid composition of the dimorphic bacterium Caulobacter crescentus was found to consist primarily of 16- and 18-carbon fatty acids, both saturated and monounsaturated, in agreement with the findings of Chow and Schmidt (J. Gen. Microbiol. 83:359-373, 1974). In addition, two minor but as yet unidentified fatty acids were detected. Chromatographic mobilities suggested that these fatty acids may be a cyclopropane and a branched-chain fatty acid. In addition, we demonstrated that the fatty acid composition of wild-type C. crescentus can be altered by growing the cells in medium supplemented with any one of a variety of unsaturated fatty acids. Linoleic acid, a diunsaturated fatty acid which is not synthesized by C. crescentus, was incorporated into phospholipids without apparent modification. In addition, we found that C. crescentus, like Escherichia coli, synthesizes vaccenic acid (18:1 delta 11,cis) rather than oleic acid (18:1 delta 9,cis). This result allowed us to deduce that the mechanism of fatty acid desaturation in C. crescentus is anaerobic, as it is in E. coli. Finally, we examined the fatty acid biosynthesis and composition of two unsaturated fatty acid auxotrophs of C. crescentus. Neither of these mutants resembled the E. coli unsaturated fatty acid auxotrophs, which have defined enzymatic lesions in fatty acid biosynthesis. Rather, the mutants appeared to have defects relating to the complex coordination of membrane biogenesis and cell cycle events in C. crescentus.

Bacteria↗
PubMed1981

Phospholipid biosynthesis is required for stalk elongation in Caulobacter crescentus.

Membrane phospholipid synthesis was inhibited in Caulobacter crescentus by growth of a glycerol auxotroph in the absence of glycerol or by treatment with the antibiotic cerulenin. It was observed that the final step in the swarmer cell-to-stalked cell transition, stalk elongation, was inhibited under these conditions. Since an early effect of inhibiting phospholipid synthesis in C. crescentus is the termination of deoxyribonucleic acid (DNA) replication (I. Contreras, R. Bender, A. Weissborn, K. Amemiya J. D. Mansour, S. Henry, and L. Shapiro, J. Mol. Biol. 138:401-410, 1980), we questioned whether the inhibition of stalk formation was due directly to the inhibition phospholipid synthesis or secondarily to the inhibition of DNA synthesis. Under conditions which inhibited DNA synthesis but permitted phospholipid synthesis, i.e., growth of a temperature-sensitive DNA elongation mutant at the restrictive temperature or treatment with hydroxy-urea, stalk elongation occurred normally. Therefore phospholipid synthesis is required for stalk elongation in C. crescentus.

Bacteria↗