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Biomedical subjects

J Rubin

Publications and source records attributed to J Rubin.

At least 361 records · Page 20Linked to original sources

The effect of hyoscine and atropine on the lower oesophageal sphincter.

The effects of intravenous hyoscine 0-4 mg and atropine 0-6 mg on lower oesophageal sphincter tone were studied in normal human subjects. Hyoscine and atropine both decreased the lower oesophageal sphincter (L.O.S) pressure by approximately 11 cm H2O (p less than 0-01). There was also an increased incidence of reflux as seen by an indwelling pH electrode in the lower oesophagus. These findings are relevant to the preoperative preparation of patients presenting for emergency obstetrical anaesthesia; since gastro-oesophagus reflux and pulmonary aspiration of acid gastric content continues to be a significant cause of morbidity and mortality.

Adult↗

Laryngeal incompetence during neuroleptanalgesia in combination with diazepam.

In eight patients, following carotid angiography under neuroleptanalgesia, a radiopaque dye was instilled into the pharynx. The chest was x-rayed 15 min later. All eight patients were observed to have aspirated the dye. The technique of neuroleptanalgesia described should not be used without safeguarding the airway in patients liable to regurgitate and inhale gastric contents.

Adult↗

Atomic coordinates and molecular conformation of yeast phenylalanyl tRNA. An independent investigation.

The atomic coordinates of yeast tRNA(Phe) in the monoclinic crystal form have been determined by an independent analysis from a model built into a 3 A MIR map. The overall molecular structure is found to be in agreement with those reported for the same crystal form by Ladner et al. (1975) and for the orthorhombic form by Quigley et al. (1975) and Kim et al. (1975). However, significant differences between any two of the four models are found in certain local regions of the molecule. The structure is analyzed in terms of the nucleotide stereochemistry and internucleotide phosphodiesters. A striking observation is that the majority of the nucleotide moieties occur in the conformation preferred by the constituent mononucleotides themselves. The internucleotide P-O bonds afford the primary source of flexibility for the folding of the polynucleotide backbone while the sugar pucker and C(4')-C(5') torsions provide the secondary source of flexibility.

Binding Sites↗

The administration of metoclopramide with atropine. A drug interaction effect on the gastro-oesophageal sphincter in man.

The effects of intravenous atropine 0-6 mg alone, metoclopramide (Maxolon) 10mg alone and atropine 0-6 mg and metoclopramide 10 mg in combination, on the lower oesophageal sphincter (LOS) were studied in three groups of normal human volunteers. Atropine decreased the LOS pressure by an average of 8 cm H2O (P less than 0-001), whereas metoclopramide increased the LOS pressure by a mean of 29 cmH2O compared to basal values (P less than 0-001). In contrast, no change in sphincter tone was noted following injection of atropine-metaclopramide mixture. These findings are relevant to the pre-operative preparation of patients presenting for emergency anaesthesia, since gasgro-oesophageal reflux and pulmonary aspiration of acid gastric content continues to be a significant cause of morbidity and mortality.

Adolescent↗

Management of peritonitis and bowel perforation during chronic peritoneal dialysis.

Peritonitis and bowel perforation are the most serious conditions of peritoneal dialysis. This paper reports our experience with these two complications among 87 patients who were admitted to our porgram during a 3.5-year period and were treated with chronic peritoneal dialysis for periods up to 38 months (average 9 months). Approximately 6,000 dialyses were performed. Peritonitis occurred seven times in six patients (0.1%) and five patients had six episodes of bowel perforation (0.1%). All patients were successfully managed with conservative treatment, consisting of continuous peritoneal dialysis and intraperitoneal and systemic antibiotics. Careful aseptic technique seems to be the only necessary factor in prevention of peritonitis.

Adolescent↗

The signal from fruiting body and conus tips of Dictyostelium discoideum.

Tips from fruiting bodies and conuses were transplanted into interphase fields of Dictyostelium discoideum amoebae. Progressively increasing concentrations of beef-heart phosphodiesterase added to the fields significantly decreased the chemotactic range of the responding amoebae. The findings suggest that the tip secretes c-AMP. We also find that the chemotactic range is independent of the size of the tip implying that the tip may produce a regulating gradient.

Animals↗

The tip of the Dictyostelium discoideum pseudoplasmodium as an organizer.

We have extended Raper's original work on the organizing ability of the tip of the Dictyostelium discoideum slug. Our new results are that tips from all multicellular (pseudoplasmodial) stages act as organizers; that the structure organized by a tip depends on the developmental stage of the cells responding to the tip's signal; that tips from all stages release a qualitatively similar signal which is continuous, most probably a gradient of c-AMP; and that the signal from fruiting-body tips appears stronger than that from conus tips. We discuss these results with reference to the control of morphogenetic movement and patterned differentiation and point out that the D. discoideum tip is analagous to a classical organizer, whose signal is interpreted according to the state of determination of cells in its field of influence.

Cell Differentiation↗

Crystal structure of a naturally occurring dinucleoside monophosphate: uridylyl (3',5') adenosine hemihydrate.

The crystal structure of uridylyl (3',5') adenosine hemihydrate has been analyzed by x-ray diffraction. The two independent molecules found in the asymmetric unit exhibit conformations that differ significantly from those found in double-helical RNA. The conformational information obtained from this analysis provides considerable insight into the possible conformations of nonhelical "loop" regions of transfer RNA, as well as single-stranded regions of nucleic acids in general.

Base Sequence↗