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Biomedical subjects

J Jones

Publications and source records attributed to J Jones.

At least 613 records · Page 34Linked to original sources
PubMed1987

Metabolism of glucose into glutamate via the hexose monophosphate shunt and its inhibition by 6-aminonicotinamide in rat brain in vivo.

The treatment of rats for 4 h with 6-aminonicotinamide (60 mg kg-1) resulted in an 180-fold increase in the concentration of 6-phosphogluconate in their brains; glucose increased 2.6-fold and glucose 6-phosphate, 1.7-fold. Moreover, lactate decreased by 20%, glutamate by 8% and gamma-aminobutyrate by 12%, and aspartate increased by 10%. No significant changes were found in glutamine and citrate. In blood, 6-phosphogluconate increased 5-fold; glucose, 1.4-fold and glucose 6-phosphate, 1.8-fold. The metabolism of glucose in the rat brain, via both the Embden-Meyerhof pathway and the hexose monophosphate shunt, was investigated by injecting [U-14C]glucose or [2-14C]glucose, and that via the hexose monophosphate shunt alone by injecting [3,4-14C]glucose. The total radioactive yield of amino acids in the rat brain was 5.63 mumol at 20 min after injection of [U-14C]glucose, or 5.82 mumol after injection of [2-14C]glucose; by contrast, it was 0.62 mumol after injection of [3,4-14C]glucose. The treatment of rats with 6-aminonicotinamide showed significant decreases in these values, owing to decreases in the radioactive yields of glutamate, glutamine, aspartate, gamma-aminobutyrate, and alanine+glycine+serine. Glutamate isolated from the brain contained approximately 43% of its radioactivity in carbon 1 after injection of [3,4-14C]glucose, in contrast to 13% and 18% after injection of [U-14C]glucose and [2-14C]glucose, respectively, in both the control and treated rats. The calculations based on these findings showed that approximately 69% of the 14C-labelled glutamate was formed from [14C]acetyl coenzyme A (acetyl CoA) and the residual 31% by 14CO2 fixation of pyruvate after injection of [3,4-14C]glucose in both control and treated rats. The results gave direct evidence that glutamate and gamma-aminobutyrate in the brain were formed by metabolism of glucose via the hexose monophosphate shunt as well as via the Embden-Meyerhof pathway. From the radioactive yields of glutamate formed via [14C]acetyl CoA it was estimated that approximately 7.8% of the total glucose utilized was channelled via the hexose monophosphate shunt. Assuming that [14C]glutamate formed by carbon-dioxide fixation of pyruvate was also dependent on the metabolism of glucose through the hexose monophosphate shunt, the estimated value was approximately 9.5% of the total glucose converted into glutamate. The results of the present investigation, taken in conjunction with other findings, suggest that the utilization of glucose via the hexose monophosphate shunt is functionally important in the rat brain.

6-Aminonicotinamide↗
PubMed1987

Reliability of a single beta-thromboglobulin measurement in a diabetic population: importance of PGE1 in anticoagulant mixture. Damad Study Group.

During the collection of samples for plasma beta-thromboglobulin (beta-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single beta-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE1. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p less than 0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artificially high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGE1 decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

Adult↗
PubMed1987

The distinction by light and electron microscopy of two types of cone containing colorless oil droplets in the retina of the turtle.

In turtle retina the spectral types of cones can be distinguished by the characteristic colors of their oil droplets. Blue cones until recently were thought to be identified by their colorless oil droplets. Now it has been shown that the cones containing colorless oil droplets can be subclassified into two types: one type in which the oil droplet fluoresces under ultraviolet stimulation and the other type in which it does not. We have attempted to recognize these two subclasses of cones with colorless oil droplets by the following anatomical techniques. (1) Light microscopy of fresh retina, (2) light microscopy of isolated cells in tissue culture and (3) light and electron microscopy of photoreceptors stained with horseradish peroxidase in whole-mount. The cone type with the colorless fluorescent oil droplet (FC cone) has an oil droplet size intermediate between those contained in the green single cones and the cone with the clear colorless oil droplet (CC cone); it typically has a short (15 microns long) oblique axon and it forms approximately 13% of the cones in the retina. The CC cone, on the other hand, is recognized by having the smallest oil droplet of all cone types which is nonfluorescent; it has a very long (30 microns long) oblique axon and forms 5% of the cones in the retina. We discuss the similarity of the FC cone morphology and distribution to blue cones in other vertebrate retinas.

Animals↗
PubMed1987

Repetitive doses of activated charcoal in the treatment of poisoning.

Activated charcoal has found a renewed role in the management of overdosed patients. Routinely administered to reduce the gastrointestinal (GI) absorption of many drugs, growing evidence indicates that repeated doses of charcoal also may enhance drug elimination. Some drugs are excreted into the bile or gastric fluids (phencyclidine, digoxin) and are reabsorbed. Other drugs (theophylline, phenobarbital) can diffuse from the plasma into the lumen of the GI tract. Activated charcoal is administered at regular intervals to sequester these toxins in the GI tract, eventually causing their excretion in feces. This article reviews the evidence for the safety and efficacy of repetitive charcoal therapy. While supportive management remains the mainstay of therapy in poisoned patients, activated charcoal is inexpensive, effective, simple to administer, and may obviate the need for more invasive methods of toxin removal.

Acute Disease↗
PubMed1987

Toxic smoke inhalation: cyanide poisoning in fire victims.

The most common cause of death in fires is the inhalation of noxious gases rather than thermal injury. Hydrogen cyanide gas, the most toxic product of combustion, seldom is recognized as a significant hazard in smoke inhalation. During the first four months of 1986, toxic amounts of cyanide were found in four of the six fatalities from house fires in Akron, Ohio. These cases illustrate the increasing frequency of cyanide poisoning in household fires. Sources of cyanide toxicity include the increased use of synthetic polymers in building materials and furnishings. Prompt recognition of and therapy for cyanide intoxication may reduce the morbidity and number of delayed deaths in fire victims. The key point in the diagnosis of cyanide poisoning is a high index of suspicion. The clinical presentation of cyanide intoxication, its diagnosis, and subsequent treatment are discussed. Finally, a prehospital protocol for treating smoke-inhalation victims who may have been exposed to cyanide gas is suggested.

Aged↗
PubMed1987

Immunity to diphtheria in young British adults.

Of 906 recruits aged between 16 and 20 years who were Schick-tested upon entry to the Royal Air Force, 775 were tested for circulating Corynebacterium diphtheriae antitioxin by means of an indirect haemagglutination (IHA) method. Of the total population, 95.7% were Schick-test negative, 3.5% were Schick-test positive and 0.8% gave pseudo-reactions. Of those tested by the IHA test, 37.7% were regarded as immune, 47.0% as 'immune-susceptible' and 15.3% as non-immune. Discrepancies between the two tests were discovered. Of those persons found to be Schick-test positive, 34.6% possessed circulating antitoxin; of those Schick-test negative, 13.5% were regarded as non-immune. A history of diphtheria immunisation in childhood was found to be a poor predictor of immunity. A protocol for selective diphtheria immunisation of adults is proposed.

Adolescent↗
PubMed1987

Teaching research in the emergency medicine residency curriculum.

Research in emergency medicine is a necessary component for the growth and development of the academic discipline. Although the need exists for competent physician investigators, most graduates of emergency medicine residencies have had little structured education in research design or methodology. This is particularly true in community hospital programs with little funding allocated to research, limited facilities, and few staff members actively involved in research. Our purpose is to describe a research curriculum designed to operate within a community-based residency program. This curriculum identifies a detailed set of educational objectives in research techniques with the expectation that on completion of the residency program, the resident will be able to critically evaluate medical literature and independently design a research project. We have developed a specific plan for meeting these objectives with coordinated seminars, readings, journal clubs, research projects or exhibits, and professional conferences. We suggest some practical methods of motivating residents and attending staff to pursue clinical investigation.

Curriculum↗
PubMed1987

Magnesium levels in cardiac arrest victims: relationship between magnesium levels and successful resuscitation.

Multivariate analysis was performed to evaluate significant differences between electrolytes, serum magnesium, and successful resuscitation in cardiac arrest victims in a prospective controlled study. Twenty-two cardiac arrest victims having ventricular fibrillation or tachycardia, electromechanical dissociation, or asystole were compared with 19 matched controls with no ventricular arrhythmias. Of the control group, one was hypermagnesemic (5%), 17 normomagnesemic (90%), and one hypomagnesemic (5%). In the arrest group, eight were hypermagnesemic (36%), nine normomagnesemic (41%), and five hypomagnesemic (23%). Thirteen of 22 cardiac arrest victims (59%) had an abnormal serum magnesium level. All hypermagnesemic and hypomagnesemic patients expired (100%). In the normomagnesemic group, four out of nine (44%) were successfully resuscitated. A positive correlation was identified between normomagnesemia and successful resuscitation (P less than .01). There was no correlation between other electrolytes and successful resuscitation (P greater than .05).

Arrhythmias, Cardiac↗
PubMed1987

Group G streptococcal bacteremia in a chronically constipated adolescent.

A chronically constipated, mentally retarded male adolescent was admitted on two occasions with gastroenteritis symptoms and stool positive for group G Streptococcus. The first episode was also associated with group G streptococcal bacteremia. This case of group G streptococcal disease is unique in that the primary symptoms were those of gastroenteritis. In the context of chronic constipation in colonic distention, the case appears to support the hypothesis of Watsky et al that group G streptococcal bacteremia is promoted by processes which breach anatomic mucosal or epithelial infection barriers.

Adolescent↗
PubMed1987

Physiological growth hormone secretion during slow-wave sleep in short prepubertal children.

The usefulness of a limited nocturnal GH profile has been evaluated for the assessment of physiological GH secretion. We have analysed the complete overnight GH and sleep profiles of 20 short prepubertal children, sampled at 15-min intervals. The mean age was 9.1 years (range 4.3-11.7 years) and mean height velocity standard deviation score (SDS)-1.0 (range -2.4 to +0.4). The sleep stage in which the maximal GH value was reached varied considerably between the patients. Only 55% achieved the maximal GH value during the first slow-wave sleep period, and 65% in the first 2 h of sleep. The maximal values during the first slow-wave period correlated weakly with the sum of the nocturnal peak values and the total area under the curve of the complete GH profile. None of these parameters correlated with height velocity. We conclude that at present there is no substitute for complete overnight or 24 h GH profiles for the assessment of physiological GH secretion, but the clinical significance of the variations seen remains unclear.

Body Height↗
PubMed1987

Emergency care teamwork.

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Emergency Medical Service Communication Systems↗
PubMed1987

Protracted severe immune dysregulation induced by cardiopulmonary bypass: a predisposing etiologic factor in blood transfusion-related AIDS?

A large percentage of patients with blood transfusion related AIDS received their transfusion during cardiac surgery requiring cardiopulmonary bypass. We hypothesized that the procedure of cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery might be associated with severe immune dysregulation and hence predispose this group in particular to the acquisition of blood transfusion transmitted AIDS. T-cell subset enumeration and their ratio (T4/T8) and T-cell function (local GVH reaction) were serially studied before, during, and 1 and 6 days after surgery in 15 patients undergoing cardiac surgery requiring CPB, in 10 patients undergoing cancer resections (CA), and 11 patients without cancer undergoing elective, non-cardiac general surgical procedures (GEN). Compared to the preoperative values, a significant decline (p less than 0.002) in T4/T8 ratios occurred during CPB (1.63 +/- 0.80 vs 2.55 +/- 0.95), during CA (1.26 +/- 0.71 vs 1.81 +/- 0.72), and during GEN procedures (1.18 +/- 0.59 vs 1.64 +/- 0.68). T4, T8, and T4/T8 ratios returned to preoperative values in both the CA and GEN groups by the first postoperative day; in contrast, T4/T8 ratios remained significantly depressed (p less than 0.05) in CPB patients on the first and also on the sixth postoperative days when compared to preoperative values. This sustained depression in T4/T8 ratios is attributable to a significant increase in the proportion of T8 (suppressor cell) subset in the CPB patients which persisted through the sixth postoperative day. In contrast, in CA and GEN, the proportion of T8 subset returned to the preoperative level by the sixth postoperative day.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1987

Prophylaxis of upper gastrointestinal tract bleeding in mechanically ventilated patients. A randomized study comparing the efficacy of sucralfate, cimetidine, and antacids.

Sixty-two mechanically ventilated patients were randomized into three study groups to compare the efficacy of sucralfate vs cimetidine and antacid regimens for the prevention of upper gastrointestinal tract bleeding. Only five study patients (8%) developed bright-red blood per nasogastric tube; four patients received the antacid regimen and one received cimetidine. None of the patients receiving sucralfate developed acute upper gastrointestinal tract bleeding. Bleeding was not severe enough in any patient to require endoscopy or surgery. There were no significant differences in the three groups when several major risk factors for gastrointestinal tract bleeding were analyzed, including sepsis, hypotension, steroid use, adult respiratory distress syndrome, gastric pH of 4 or less, previous peptic ulcer disease, peritonitis, and jaundice. A significantly higher incidence of acute renal failure was noted in the antacid-treated group when compared with the cimetidine and sucralfate groups. We find preliminary evidence that sucralfate is as efficacious as and more cost-effective than either cimetidine or antacids for prophylaxis of stress-related gastrointestinal tract bleeding in the critically ill ventilator-dependent patient.

Acute Kidney Injury↗