Purification and identification of an impurity in bulk hydrochlorothiazide.

Hydrochlorothiazide (6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide) (HCTZ) 1 is a widely used diuretic and anti-hypertensive. Recently, the Pharmeuropa recognized a new impurity initially thought to be an HCTZ dimer 6, which consists of the active drug (HCTZ) linked via the former beta-ring methylene to a known degradate, 5-chloro-2,4-disulfamylaniline 2. In an effort to meet a new requirement, an analytical high-pressure liquid chromatography method was developed that was selective and sensitive to the subject impurity. The impurity was concentrated and purified using a combination of solid phase extraction and reverse-phase high-pressure liquid chromatography. Subsequently, the impurity has been identified as a specific HCTZ-CH2-HCTZ isomer utilizing a variety of analytical techniques, including hydrolysis, ultraviolet spectroscopy, liquid chromatography/mass spectrometry, and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The data resulting from the application of these analytical techniques confirm the identity of the impurity as a methylene bridged pair of HCTZ molecules; however, a total of six possible isomers 7a-f exist because of the presence of three reactive amines/sulfonamides on each HCTZ molecule. One unique molecular structure (4-[[6-chloro-3,4,-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide]-methyl]-chloro-3-hydro-H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide) 7f was identified using two-dimensional COSY, NOESY, and TOCSY 1H NMR experiments.

Liquid chromatography-mass spectrometry and proton nuclear magnetic resonance characterization of trace level condensation products formed between lactose and the amine-containing diuretic hydrochlorothiazide.

Trace levels of condensation products between lactose and the amine-containing diuretic hydrochlorothiazide are formed when a mixture of the two solids containing 30% weight water is heated at 60 degrees C for 2 weeks. The two most abundant condensation products were characterized by liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. Under these relatively mild conditions of formation, the amine-lactose reaction products are limited to those involving the elimination of only a single molecule of water, rather than the multiple-water eliminations associated with later stages of the Maillard reaction. The spectroscopic data clearly show that the primary condensation products are cyclic N-substituted glycosylamines rather than Schiff base, 1,2-enolic forms, or Amadori rearrangement products of identical mass. In solution, the two most abundant N-substituted glycosylamines are shown to be in a kinetically slow equilibrium with each other, most likely through a mutarotation involving the intermediate formation of the acyclic Schiff base.

When the lung fails. Acute respiratory distress syndrome in children.

Caring for the child with ARDS is a challenge. Many new ventilatory techniques have been introduced to maximize a good outcome. Nevertheless, it is obvious that regardless of therapy, expert nursing care is critical. Astute observation, knowledge of the different therapies, identification of complications, and attention to the needs of the child and family are needed to make care truly holistic.

Solute-induced shift of phase transition temperature in Di-saturated PC liposomes: adoption of ripple phase creates osmotic stress.

We have examined the calorimetric behavior of large liposomes consisting of symmetric saturated chain phosphatidylcholines. Most notably, for systems made in solutions containing solute (e.g., NaCl, glucose, etc.) there was an additional major endotherm just below the main phase transition temperature. The new endotherm was found to represent a population of lipid whose main phase transition was shifted to lower temperature due to an induced osmotic stress across the membrane. Absent for isoosmotic systems, the osmotic stress was created when the liposome internal volume decreased, a consequence of the Lbeta' (gel) to Pbeta' (rippled) phase transition. That is, rippling of the membrane caused vesicle volume to decrease (> or = 28%) and because the free flow of water outward was restricted by solute, an osmotic gradient was created where none had existed before. The distribution of enthalpy between the new shifted Tm and the expected Tm correlated with the percent of lipid in the outer bilayer and it was concluded that only the outer bilayer sensed the induced stress. Internalized liposome structures were shielded, thus explaining the persistence of the expected Tm in preparations made in solute. The shift in Tm (deltaTm) was discrete and linearly dependent upon lipid chain length for the PC series di-17:0 (deltaTm approximately 1.4 degrees C) through di-20:0 (deltaTm approximately 0.6 degrees C), suggesting a structural change (i.e., lipid packing/orientation) was involved. Although freeze-fracture electron microscopy of stressed and unstressed bilayers revealed no differences in ripple periodicity there were differences in surface features and in vesicle shape. The fact that this phenomenon has gone unnoticed for MLVs is probably due to the fact that these systems are known to exclude solute and thus exist under osmotic compression.

Caught in the crossfire. Children, guns, and trauma: an update.

The dramatic increase in violence-related deaths in the last few years demands that violence be recognized as a public health emergency. Even though mortality rates in children have decreased overall and deaths from injuries have also decreased, the rate of violence-related mortality has increased. Violence does not know the limits of cities, age, sex, or race; everyone, everywhere is affected. The recognition of violence as a leading cause of mortality and morbidity in children must become a national priority. By making a commitment to tackle the problem of violence, nurses and other health care professionals can make a significant contribution to society at large.

Endogenously opsonized particles divert prostanoid action from lethal to protective in models of experimental endotoxemia.

We report that, in rats, the lethal consequences of high-dose endotoxin challenge are exacerbated by the intravascular administration of prostaglandin E1 but attenuated by the intravascular administration of endocytosable particles. This protection is mediated by opsonins. Nonopsonizable particles were unable to provide protection unless first pseudoopsonized with antibody directed against the CR3 (CD11b/CD18) phagocyte receptor. We show that endogenously opsonized particles can act in concert with prostaglandin E1 (putatively by elevation of neutrophil intracellular cAMP and the resultant downregulation of CR3) to completely rescue animals from the lethal late-stage sequelae of experimental endotoxemia. These data illustrate that the interaction of particles with cellular receptors can transform the overall systemic response to prostaglandin E1 from pro- to antiinflammatory. This suggests a role for multiple receptor engagement events in defining the systemic prostaglandin response and offers a rationale for developing new therapeutic modalities in the treatment of sepsis and other inflammatory diseases.

Combination of potentiometry and resonance Raman spectroscopy for the analysis of a redox protein.

This paper describes apparatus and procedures for combining resonance Raman and optical absorption spectroscopies with potentiometry for the study of redox-active heme proteins. A specially designed anaerobic titration cell is described which allows for the laser excitation of the sample and the monitoring of both Raman scattered light and directly transmitted light from an optical source. New procedures for utilization of A/D and D/A converters on a standard I/O computer card are described, which allow for computer-controlled potentiometry and coulometry. The system was tested with cytochrome c, a well-characterized respiratory protein. The correct values for the midpoint potential and electron number of the Nernst equation were obtained both by the optical absorption and resonance Raman measurements.

Near infrared spectral changes of cytochrome aa3 during potentiometric titrations.

Singular value decomposition (SVD) was used to deconvolute the spectral changes occurring in the near infrared region during potentiometric titrations of cytochrome aa3. Overall oxidized minus reduced difference spectra revealed a broad absorbance feature centered near 830 nm with an apparent Em near 250 mV. However, SVD did not isolate any spectral species with an absorbance centered near 830 nm. It was found that the spectral changes occurring in the wavelength region from 650 to 950 nm were associated mainly with cytochromes a and a3. It was concluded that the absorbance at 830 nm should not be used as an independent measure of the concentration of CuA in cytochrome aa3.

Caught in the crossfire: children, guns, and trauma.

Violence, especially that related to the use of firearms, has become a leading cause of death in children in the United States. Providing physical and psychosocial care for the child with a gunshot wound is a nursing challenge. Nurses can and must play a major role in helping to prevent this public health problem.

Resonance Raman and optical spectroscopic monitoring of heme a redox states in cytochrome c oxidase during potentiometric titrations.

Resonance Raman spectroscopy is used to monitor the redox state of heme a and heme a3 centers in cyanide-inhibited and native cytochrome oxidase during potentiometric titrations. Specific vibrational modes are resolved for each reduced heme with 441.6-nm excitation while oxidized species show vanishingly small Raman intensities. The voltage dependencies of the Raman intensities of reduced heme a and reduced heme a3 modes are quantitatively measured and used to extract heme a and a3 midpoint potentials. In the cyanide-bound enzyme, in which heme a3 remains in the oxidized state, the Raman data indicate that heme a centers exhibit complex Nernstian behavior with two Em values near 350 and 260 mV. In the native enzyme, this resonance Raman-potentiometric method reveals significantly different redox behavior for the two hemes. Heme a centers are described by two effective Em values near 350 and 220 mV, while heme a3 centers have lower Em values near 260 and 200 mV. Singular value decomposition analysis of optical spectral changes supports the Raman data. These results are in contrast to models of cytochrome oxidase redox behavior in which heme a and heme a3 are thought to have essentially identical midpoint potentials.

The pediatric cardiovascular surgery patient: a case study.

The pediatric cardiovascular surgery patient has many needs, based not only on the complexity of the surgical procedure, but also on anatomic, physiologic, and emotional differences. These differences have implications for nursing care in the postoperative period. This article focuses on the special needs of a child who required correction of a congenital heart defect. The specialized knowledge required by the pediatric critical care nurse to make accurate assessments of the child's status and to intervene appropriately are emphasized. Issues surrounding the care of the family of the child who experiences cardiac surgery are highlighted.

A comparison of close proximity concentric and modified single fiber electromyographic recordings from extensor digitorum communis.

Using a combined concentric (CN) and modified single fiber (MSF) electromyography (EMG) needle electrode with both recording surfaces at the tip approximately 25 microns apart, 30 motor unit action potentials (MUAP) were recorded from one extensor digitorum communis (EDC) muscle, triggering from the CN and averaging both the CN and MSF recordings. Correlations of MUAP amplitude (r = 0.767), number of turns (r = 0.839), and number of negative-going-positive-going turn (NT) (r = 0.737) between the CN and MSF recordings were statistically significant (p < 0.001). For NTs common to both recordings, correlations of rise time (r = 0.866), amplitude (r = 0.816), and interpeak interval (IPI) (r = 0.999) were statistically significant (p < 0.001). Mean +/- SD single fiber potentials (SFP), approximate SFP with rise times less than 500 microseconds, and NTs for the MSF recordings and NTs for the CN recordings were 0.73 +/- 0.69, 1.20 +/- 0.48, 1.83 +/- 0.87, and 1.93 +/- 0.78, respectively. This study supports evidence that one or a few SFP contribute to the spike component of the MUAP.

Initial assessment and stabilization of the critically injured child.

The care that the child receives during the initial resuscitation and stabilization of a life-threatening injury makes a critical difference in long-term outcome. Children who die as a result of a traumatic injury usually do so because of airway compromise, irreparable CNS injury, or bleeding. Hypoxia is the final common event by which these three kill children. If hypoxia is prevented or recognized and treated early, its effects can be reversed before they become permanent. The potential for a good outcome is maximized by expert nursing care for the critically injured child. Expert nursing care includes rapid and accurate assessment and interventions during both the primary and secondary surveys. Knowledge of the anatomic and physiologic differences between children and adults guides the nurse in holistic care of pediatric trauma victims; the nurse must also understand and address the emotional needs of the patients and their families.

Gastric fundic mucous epithelial cells isolated from omeprazole-treated guinea pigs have increased basal and hormone-stimulated growth rates.

Guinea pigs were given a daily oral dose of 400 micrograms/kg of omeprazole or the omeprazole vehicle for 6 weeks. At weekly intervals, the animal and stomach weights were recorded, the nonfasted serum gastrins measured, and the total number of gastric fundic epithelial cells were isolated and counted. Gastric mucous epithelial cells were enriched from the total gastric fundic cell population and cultured for 6 days in the absence or presence of hormones (epidermal growth factor and pentagastrin). We found that omeprazole treatment for 1-6 weeks significantly (p less than 0.05) increased the stomach weight, the nonfasted serum gastrin levels, and the total number of isolated gastric fundic and mucous epithelial cells over control animals. A significant (p less than 0.05) increase was also found in the basal and hormone-stimulated cultured growth rates of gastric mucous epithelial cells isolated from the stomachs of omeprazole-treated animals as compared with gastric mucous cells from control animals. We conclude that oral omeprazole treatment of guinea pigs will cause a specific increase in the gastric mucous cell population as well as increase the in vitro cultured gastric mucous cell basal and hormone-stimulated growth rates.

Pediatric issues in multisystem trauma.

Pediatric trauma is a national epidemic. It is the leading killer of children between the ages of 1 and 14 years, and is a major cause of disabling injuries. This is a major concern to society when one considers not only the tragedy to the family, but the implications of the loss of work potential, the length and cost of rehabilitation, and the effects on growth and development. Children have been shown to have better potential for recovery than adults, especially with head injuries. This potential can and must be maximized by expert nursing care. Nursing care includes precise assessment, formulation of nursing diagnoses based on assessment, and interventions guided by the appropriate nursing diagnosis. Research has demonstrated the positive impact nursing care has on the trauma patient; more studies are needed, especially for the pediatric trauma victim. Nurses are in a position to provide leadership in the area of pediatric injury prevention, and can educate legislators and the public about how to manage this public health epidemic. Children are our society's most precious resource. This resource can be protected by further research in all areas of pediatric trauma, including trauma prevention, resuscitation, and nursing interventions to further maximize the outcome.