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Biomedical subjects

L Fox

Publications and source records attributed to L Fox.

27 records · Page 2Linked to original sources

Pineal ultrastructure and indole profiles spanning the summer rise in arginine vasotocin immunoactivity.

A correlative radioimmunological-biochemical-ultrastructural study of the rat pineal gland was undertaken during the summer months when pineal arginine vasotocin (AVT) immunoactivity increases up to 200-fold. RIA confirmed a rapid rise in AVT activity during mid-August regardless of the time of day sampled. Pineal indoles were separated by HPLC and measured using electrochemical detection. Serotonin (5-HT) and 5-hydroxyindoleacetic acid levels were consistently elevated in daytime samples, and there was a significant trend for increased day and nighttime levels of 5-HT from July to September. Mid-dark levels of melatonin also exhibited a significant increase over the sample period. Nighttime levels of N-acetylserotonin mirrored fluctuations in 5-HT in the preceding photoperiod. Ultrastructural components implicated in peptide/protein and/or indole biosynthesis were quantified by stereological morphometry. The greatest amounts of rough endoplasmic reticulum stacks, lipid droplets, and annulate lamellae-like bodies coincided with peak AVT activity. Dense-cored vesicles and synaptic ribbons were consistently more frequent during the dark period. The number of dense-cored vesicles and nucleolar size tended to be greatest before and after the peak in AVT immunoactivity. These observations are consistent with the hypotheses that endoplasmic reticulum and lipid are functionally related to the synthesis and/or storage of peptide/protein factors and that numerical changes in synaptic ribbons and dense-cored vesicles are more closely related to day/night differences in indole metabolism.

5-Hydroxytryptophan

Fulminant meningococcemia in children.

In all respects, the child with fulminant meningococcemia presents a formidable challenge to those who care for him/her. Only with prompt recognition of the disease and immediate institution of intensive treatment can the likelihood of survival be improved and morbidity minimized.

Anti-Bacterial Agents

Clinical efficacy and toxicity of netilmicin in the treatment of gram-negative infections.

Netilmicin, a new semisynthetic aminoglycoside antibiotic, was used to treat 41 infections in 38 patients. The outcome of four infections could not be evaluated: two patients received inadequate therapy and two did not have gram-negative infections. Clinical improvement occurred in 36 (97%) of the 37 gram-negative infections, and bacteriologic cure occurred in 30 (86%) of the 35 evaluable infections. Therapeutic serum concentrations of netilmicin were readily achieved by both intramuscular and intravenous routes. Reversible ototoxic effects occurred in 1 (3%) of 35 courses of therapy evaluated, reversible nephrotoxic effects occurred in 5 (14%) of 36 courses and mild reversible alterations in liver function occurred in 3 (19%) of 34 courses. Netilmicin appears to be effective and safe in the treatment of aerobic gram-negative infections.

Adolescent

Biotyping of Escherichia coli by a simple multiple-inoculation agar plate technique.

A nine-test system using multiple-inoculation agar plates for biotyping of Escherichia coli is described. Testing of 959 strains resulted in 78 biotypes. On repeated testing, 96% of 182 strains had identical biotypes or differed by only one test. This system provides satisfactory differentiation among strains and is reproducible. Precise standardization of inoculum size is not required. Multiple inoculation allows time and cost-efficient testing of large numbers of strains.

Adult

Neonatal osteomyelitis.

To evaluate current conservative therapy and document the existence of a recent shift in etiologic agents, we reviewed the records of 45 infants who developed osteomyelitis within the first ten weeks of life and who were admitted to Babies Hospital (New York) from 1951 through 1976. Emphasis was placed on characteristics and course of the disease, etiologic agents, therapy, and outcome. Illness was diagnosed within the first two weeks of life in 34 of the 45 infants (73%). Only six had been delivered normally after normal pregnancy and led a normal life before development of ostemyelitis. Infected sites were distinctive in frequency of involvement of multiple foci (21), of facial bones (10), and of joints contiguous to infected long bones (22 of 29). Conservative therapy (nonsurgical) seems reasonable for the majority of patients. Of particular interest is documentation of a shift from Staphylococcus aureus as predominant etiologic agent before 1965 to beta-hemolytic streptococci, commonly group B, from 1965 through 1976. Data collected from the literature of the 1930s indicate that such shifts have occurred before.

Delivery, Obstetric

Clinical and laboratory study of tobramycin in the treatment of infections due to gram-negative organisms.

Tobramycin, an aminoglycoside antibiotic, was used to treat 52 infections due to gram-negative organisms in 51 patients. Complicated urinary tract infections, bacteremia and pyelonephritis accounted for 80% of the infections. The rate of immediate satisfactory response was 79%. During therapy with tobramycin, resistant organisms emerged in four patients--two Pseudomonas aeruginosa and two Escherichia coli strains. There were four superinfections with tobramycin-resistant Providencia sp. In four seriously ill patients the serum creatinine concentration increased 1 mg/dL or more; in three the increase was transient. No auditory toxicity was noted in the 19 patients in whom serial audiograms were made. In vitro testing of isolates from these patients showed that tobramycin and gentamicin had equal activity against Enterobacteriaceae. Tobramycin was two to four times more active against susceptible P. aeruginosa.

Adolescent

Therapeutic implications of gentamicin accumulation in severly diseased kidneys.

We evaluated the influence of severe disease in human kidneys (12 patients) on gentamicin sulfate accumulation characteristics in such tissue and compared the results with intrarenal tissue concentration data derived from the study of healthy dogs (54 kidneys) during variation in hydration and urinary pH. Our results indicate that, in the management of pyelonephritis complicating preexisting renal disease, if the minimal inhibitory gentamicin concentration for an infecting organism is greater than the usual therapeutic an nontoxic serum levels of the compound, then it may be appropriate to use alternate antibiotics that demonstrate lesser reduction in tissue drug accumulation in diseased kidneys.

Animals

High-performance liquid chromatographic determination of L-aspartyl-L-phenylalanine methyl ester in various food products and formulations.

A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures less than 1000 psig, an analysis can be performed in less than 15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are less than or equal to 2.5%.

Ammonia-Lyases