Simultaneous determination of sulfasalazine and its metabolites sulfapyridine and N-acetylsulfapyridine in human serum by ion-pair high-performance liquid chromatography using a polymer-based column

An HPLC method is described for the simultaneous and rapid determination of sulfasalazine (salicylazosulfapyridine) and two of its metabolites, sulfapyridine and N-acetylsulfapyridine, in human serum. The range of quantitation is 0.1 to 12 micrograms/mL for sulfasalazine and sulfapyridine and 0.25 to 12 micrograms/mL for N-acetylsulfapyridine. Serum is mixed with acetonitrile containing the internal standard sulfamethazine and the ion-pairing agent tetraethylammonium chloride. The acetonitrile extract is concentrated and analyzed by HPLC, using a new polymer-based column, and detected by UV spectroscopy at 270 nm. This paper is the first both to describe the simultaneous analysis of all three of the compounds from serum and to present sulfasalazine concentration-time data following oral administration to humans.     

An evaluation of Gambusia affinis and Bacillus thuringiensis var. israelensis as mosquito control agents in California wild rice fields

The mosquito control potential of the mosquitofish and Bacillus thuringiensis var. israelensis (Bti) were evaluated in experimental wild rice fields in Lake County, California. Fields were assigned one of six treatment: control, 1.1 kg/ha G. affinis, 3.4 kg/ha G. affinis, Bti only (6 kg/ha Vectobac granules), 1.1 kg/ha G. affinis plus Bti and 3.4 kg/ha G. affinis plus Bti. Gambusia affinis, at both release rates, significantly reduced the mosquito population at densities exceeding 100 fish/minnow trap. Treatments with Bti significantly reduced larval population; however, the populations in the fields without fish rebounded to pretreatment levels within two weeks. In fields stocked with G. affinis and treated with Bti, populations remained low after Bti treatment. Nontarget populations of arthropods were significantly lower in fields stocked with G. affinis than in fields without fish on one or more sampling dates.     

Predictors of poliomyelitis case confirmation at initial clinical evaluation: implications for poliomyelitis eradication in the Americas.

In 1985, the Pan American Health Organization adopted the goal of eradication of poliomyelitis from the Americas by 1990. Strategies to accomplish this included high vaccination coverage, aggressive outbreak control, and active surveillance for acute flaccid paralysis (AFP). Although the sensitivity of AFP surveillance for detecting paralytic poliomyelitis cases is high, studies have shown the specificity to be low. In 1990, 2497 notified cases of AFP were investigated in the Americas of which 2146 had stool specimens collected. However, only 18 were confirmed as poliomyelitis by isolation of wild poliovirus from stool specimens, 71 were classified as being compatible with poliomyelitis. Cases of AFP due to causes other than poliomyelitis result in extensive but unnecessary outbreak control measures. To predict, at initial clinical evaluation, the likelihood of future confirmation as a case of poliomyelitis, likelihood ratios (LR) were calculated for different combinations of clinical characteristics of AFP cases (249) from Mexico in 1989 and 1990. The best predictors in a child with AFP were proximal muscle involvement which progressed '4 days together with fever at onset of paralysis, and proximal and unilateral involvement with either fever at onset or paralysis which progressed '4 days. The odds would increase by 12 that the child would eventually be confirmed as poliomyelitis (19), based on a stool culture positive for wild poliovirus (95% confidence interval (CI) 2.6-55.9). A guide for use in the field is proposed whereby local health officials, often with little training in neurological evaluation, can predict at initial clinical examination the likelihood that an AFP case will subsequently be confirmed as poliomyelitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fibrolamellar carcinoma of the liver in a child: ultrastructural and immunohistologic aspects

We describe a fibrolamellar carcinoma of the liver in a 12-year-old girl and review the literature concerning the occurrence of this distinct hepatic neoplasm in children up to the age of 16 years. The results of our electron microscopic and immunohistologic studies suggest that some cells of this tumor exhibit neuroendocrine differentiation. This finding has important theoretical implications relative to the tumor's histogenesis and practical implications with respect to the search for tumor markers of clinical usefulness and possibly for therapy.     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.     

Epithelioid sarcoma. Flow cytometric study of DNA content and regional DNA heterogeneity.

The DNA content and regional DNA heterogeneity in correlation with clinicopathologic parameters and patient survival were investigated in epithelioid sarcoma. Such neoplasms preponderantly manifest diploid DNA content and a remarkably stable intratumoral and intertumoral DNA content. Small tumor size (less than 5.0 cm) and low S-phase fraction (less than 5%) were significant prognostic factors in this study. Ploidy status, mitotic rate, age, and postsurgical treatment were not significantly correlated with survival.     

The effects of menstrual phase and nicotine abstinence on nicotine intake and on biochemical and subjective measures in women smokers: a A preliminary report

Nicotine intake, menstrual and smoking withdrawal symptomatology, and baseline cortisol and MHPG were assessed in nine women smokers under conditions of ad lib smoking and overnight abstinence in three menstrual phases (early follicular, mid-to-late follicular, and late luteal). A trend towards higher nicotine intake p <0.100 was observed in the mid-to-late follicular phase. Although me menstrual symptomatology was not significantly elevated during the smoking abstinence condition overall, abstinence appeared to prevent the normal reduction in symptomatology during the mid-to-late follicular phase that occurred under conditions of ad lib smoking. Menstrual and withdrawal symptoms were highly correlated, and both were most pronounced during the late luteal/abstinence condition. The smoking-specific item “craving” reflected this pattern, though in attenuated form, suggesting that the observed exacerbation of withdrawal symptomatology was not simply due to generalized dysphoria, as queried in both instruments. MHPG was significantly elevated in the late luteal phase, whereas cortisol was significantly higher during ad lib smoking than during abstinence and tended to be highest in the mid-to-late follicular phase. Further investigation will be needed to determine the functional significance of these findings for understanding and treating smoking in women.     

Alterations in the superoxide dismutase gene of an isoniazid-resistant strain of Mycobacterium tuberculosis.

Genetic analysis of a set of six Mycobacterium tuberculosis strains differing in virulence for the guinea pig revealed an altered restriction enzyme fragmentation pattern associated with the superoxide dismutase (SOD) gene in a low-virulence, isoniazid-resistant strain. In addition, it was found that the SOD enzyme produced by the isoniazid-resistant strain differed in its electrophoretic mobility from the SOD of other M. tuberculosis strains. Detailed analysis of these strain-specific differences showed that the restriction fragment length polymorphism resulted from the presence of a copy of a repetitive element 552 bp upstream of the SOD gene and that the anomalous electrophoretic mobility arose from a single nucleotide change, resulting in replacement of an aspartic acid residue by histidine in the SOD enzyme of the isoniazid-resistant strain. Possible relationships between genetic changes and strain-dependent differences in virulence are discussed.     

An epidural abscess due to resistant Staphylococcus aureus following epidural catheterisation

We report a case of abscess formation after epidural analgesia, a rare complication that developed in our patient 13 days after placement of a thoracic epidural catheter for patient controlled analgesia. Culture of the pus grew methicillin-resistant Staphylococcus aureus . Although early diagnosis and rapid management have been reported to yield a satisfactory outcome, the case we describe ended in severe sequelae.