Agricultural use of antibiotics and the evolution and transfer of antibiotic-resistant bacteria

Microbial Resistance to antibiotics is on the rise, in part because of inappropriate use of antibiotics in human medicine but also because of practices in the agricultural industry. Intensive animal production involves giving livestock animals large quantities of antibiotics to promote growth and prevent infection. These uses promote the selection of antibiotic resistance in bacterial populations. The resistant bacteria from agricultural environments may be transmitted to humans, in whom they cause disease that cannot be treated by conventional antibiotics. The author reviews trends in antibiotic use in animal husbandry and agriculture in general. The development of resistance is described, along with the genetic mechanisms that create resistance and facilitate its spread among bacterial species. Particular aspects of resistance in bacterial species common to both the human population and the agrifood industry are emphasized. Control measures that might reverse the current trends are highlighted.     

Laparoscopic esophagomyotomy and antireflux procedure with intraoperative manometry

We have been routinely performing laparoscopic cholecystectomy and antireflux procedures. Having this experience, we decided to assess the feasibility and safety of performing a laparoscopic esophagomyotomy and antireflux procedure. Here we present a case of a 37-year-old man with a history of progressive dysphagia and a diagnosis of achalasia, made on the basis of clinical, endoscopic, and manometric studies. Preoperative manometry reported a pressure of 52 mm Hg (normal, 15-25 mm Hg) for 4.5 cm (normal, > 3 cm). Laparoscopic esophagomyotomy and anterior fundoplication were performed. The esophagomyotomy included a 6-cm segment of distal esophagus and 2 cm of stomach; postoperative manometry was 18 mm Hg for 3 cm. Eight months postoperatively, a barium swallow demonstrated no reflux. Laparoscopic esophagomyotomy and antireflux procedure can be performed with efficacy and safety, with the advantage of a shorter hospitalization and an early recovery compared with the traditional procedure. Also, we emphasize the importance of the intraoperative manometry in the relevance of a concomitant antireflux procedure.     

Factors affecting serum oxytetracycline levels in beef calves

Fifteen Aberdeen Angus steers, 295-364 kg, were dosed with either 4.4 or 11 mg of oxytetracycline hydrochloride/kg im. The antimicrobial activity of the serum was determined periodically, and the resulting data were treated statistically to determine the sources of variation. Variance in serum levels of oxytetracycline activity was attributed to dose, time of bleeding, order of dosing, animal, and assay. The total variance component was proportionately greater for the 11-mg/kg dose than for the 4.4-mg/kg dose. Animal variance increased with the higher dose level of oxytetracycline. The influence of dose on serum level was tested by applying a t test to the mean serum levels and their standard deviations at each bleeding time. The 4.4- and 11-mg/kg serum levels were significantly different (p less than 0.01) at all bleeding times. The 4.4-mg/kg serum levels mutliplied by 2.5 were not significantly different (p less than 0.05) from the 11-mg/kg serum levels at all bleeding times.     

Persistent acute renal failure with renal artery stenosis: cure following reconstructive arterial operation

A case of acute renal failure is reported in which renal function returned after surgical correction of renal artery stenosis to the sole functioning kidney. Acute renal failure associated with renal vascular lesions is reviewed. Although often clinically apparent vascular obstruction may be asymptomatic and should be considered in cases of prolonged acute renal failure.     

The decerebrate human: associative learning

Phasic changes in cardiac reactivity to innocuous stimuli, presented in a sensory disparity paradigm, were used to evaluate habituation and learning processes in five decerebrate subjects. Three subjects showed systematic changes over trials in the pattern of cardiac response to simple auditory or visual stimuli, indicative of habituation. In addition, tests for associative learning were given after repeated presentations of two paired stimuli. The appearance of a marked cardiac orienting response, to the unpredictable omission of the second stimulus, documented the development of a conditioned association in these same three subjects. One additional subject failed to show a consistent pattern of response to the stimuli, and another demonstrated a consistent response which was not subject to habituation. Overall, these findings support the view that learning processes are not solely the product of the cerebral hemispheres, but reflect general integrative features of the human neuraxis.     

Significance of adrenal hormones in brain energy metabolism

Intensity of glycolysis was studied under conditions of immobilization stress and adrenalectomy as well as with administration of adrenaline and hydrocortisone. The processes of aerobic glycolysis, activity of enzymes of the tricarboxylic acid cycle and mitochondria respiratory chain, content of total, free and protein-bound glycogen, glucose-I-phosphate, glucose-6-phosphate, pyruvate, alpha-ketoglutarate, cytrate and macroergs in the brain are shown to depend on the level of adrenal hormones producing a multilateral effect on a series of energy metabolism links.