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Biomedical subjects

M Arnold

Publications and source records attributed to M Arnold.

At least 181 records · Page 10Linked to original sources
PubMed1984

Telemetric ICP monitoring after surgery for posterior fossa and third ventricular tumors. Technical note.

After surgery for posterior fossa or third ventricular tumors, hydrocephalus may persist or evolve. Proper management of this complication requires timely detection. Temporary external ventricular drainage has been suggested by some authors as an adjunct to clinical observations and radiographic studies for unshunted patients. As an alternative, the authors have used a telemetric method of pressure monitoring in association with a ventricular catheter and subcutaneous reservoir. This has been found useful in eight patients without the disadvantages inherent in other methods of management.

Brain Neoplasms↗
PubMed1983

Acute respiratory alkalosis and acidosis and rabbit intestinal ion transport in vivo.

The effects of acute respiratory alkalosis and acidosis on electrolyte transport in the rabbit ileum, colon, and gallbladder were studied. During in situ perfusion, anesthetized animals were ventilated with 0, 3, or 8% CO2 gas, creating states of alkalosis (pH 7.49 +/- 0.01, PCO2 = 27.0 +/- 0.9 mmHg, HCO3 = 21.7 mM), normocapnia (pH 7.38 +/- 0.02, PCO2 = 41.3 +/- 1.1 mmHg, HCO3 = 25.9 +/- 0.4 mM), and acidosis (pH 7.21 +/- 0.01, PCO2 = 66.3 +/- 1.3 mmHg, HCO3 = 28.1 +/- 0.8 mM). In the ileum alkalosis decreased the net absorption of water (-36%), sodium (-44%), and chloride (-27%), whereas acidosis had the opposite effect on water (+69%), sodium (+98%), and chloride (+32%) absorption and reduced bicarbonate secretion. Small changes in net potassium absorption occurred in the direction of water movement. There was no effect on the ileal transmural potential difference (PD). The colon and gallbladder did not respond to the acid-base disorders with changes in electrolyte transport or PD. These results suggest that systemic pH and/or PCO2 affect an electroneutral sodium chloride absorptive process in the rabbit ileum. The simple presence of this absorptive process in the gallbladder was not a sufficient basis for this organ to respond to alterations in systemic pH.

Acidosis, Respiratory↗
PubMed1983

Bactericidal activity of antimicrobial drugs in simulated urine specimens at various temperatures of incubation.

A total of 23 antimicrobial drugs were examined for bactericidal activity in midstream-urine against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, or Streptococcus faecalis ATCC 29212 at incubation temperatures of 35, 22, and 7 degrees C, respectively. The majority of chemotherapeutic agents significantly reduced bacterial inocula within 2 h at 35 degrees C. At room temperature, most drugs required 4 h for significant killing activity to ensue. At 7 degrees C only nitrofurantoin, polymyxin B, and rifampin were significantly active within 2 to 4 h following exposure. Following prolonged (overnight) incubation at 7 degrees C, however, 10 of 23 drugs (amikacin, cefotaxime, chloramphenicol, gentamicin, nalidixic acid, netilmicin, nitrofurantoin, polymyxin B, rifampin, and vancomycin) effected reduction of bacterial colony counts of greater than or equal to 50%. On the basis of these data it is recommended that urine specimens from patients with known antibacterial chemotherapy should not be refrigerated for longer than 2 to 4 h following collection.

Adult↗
PubMed1982

Endotoxin-stimulated opioid peptide secretion: two secretory pools and feedback control in vivo.

Small doses of endotoxin evoked a dramatic biphasic response of opioid peptide secretion into blood in sheep. The first phase began within minutes and coincided with a brief hypertensive response to endotoxin well before the appearance of fever or hypotension. The ratio of beta-endorphin to beta-lipotropin fell abruptly at the onset of the second phase of release, suggesting early depletion of a pool rich in beta-endorphin and subsequent emergence of a pool rich in unprocessed precursor. The concentration of cerebrospinal fluid opioids increased tenfold during the second phase. Naloxone administration augmented endotoxin-induced opioid secretion in both early and late phases, suggesting a short-loop feedback regulation of stress-induced endorphin secretion.

Animals↗