Pharmacokinetics of benzydamine after intravenous, oral, and topical doses to human subjects

The pharmacokinetics of the anti-inflammatory drug benzydamine were determined after intravenous infusion of 5 mg to six healthy male subjects. Benzydamine was characterized as a drug of relatively low systemic clearance (ca. 160 ml min-1) but high volume of distribution (ca. 1101); the apparent terminal half-life in plasma was ca. 8 h. Benzydamine was well absorbed after oral administration, as indicated by a mean systemic availability of 87 per cent. However, absorption of the drug was low (less than 10 per cent of the dose) after its use by male subjects as a mouthwash, or after its application to female subjects as dermal cream and vaginal douche preparations. The data suggest that benzydamine is generally not well absorbed through the skin and non-specialized mucosae, thereby limiting unrequired systemic exposure to this drug when it is used by these routes.

An open study to compare the pharmacokinetics, safety and tolerability of a multiple-dose regimen of azithromycin in young and elderly volunteers

An open, parallel study was conducted to compare the pharmacokinetics of oral azithromycin in young and elderly healthy volunteers. A total of 12 young subjects (six males, six females) with a mean age of 29 (range 22-39) years and another 12 elderly subjects (six males, six females) with a mean age of 72 (range 67-80) years were given a standard five-day therapeutic regimen of azithromycin (500 mg single dose on day 1 and 250 mg once daily on days 2-5). Pharmacokinetic results indicated that Cmax, Cmin and urinary excretion were similar in the two age groups. Mean AUC0-24 was significantly greater (2.7 micrograms.h/ml) at day 5 in the elderly subjects compared with the younger age group (AUC0-24 = 2.1 micrograms.h/ml) (p = 0.041). Similarly, tmax values on days 1 and 5 were significantly greater in the elderly subjects; 3.8 h compared with 2.5 h in young subjects (p = 0.005) on day 1 and 4.4 h, compared with 3.2 h (p = 0.047) on day 5. There was also evidence of an inverse relationship between creatinine clearance and AUC0-24 (p less than 0.01) but not urinary excretion or Cmax. Despite these observations, it is concluded that the differences between the two age groups were of insufficient magnitude to warrant a dose modification in elderly subjects with only mild renal impairment. Side effects, chiefly headache and gastrointestinal symptoms, were reported by seven subjects in each group. No subject, however, was withdrawn from the study and there were no treatment-related abnormalities in any of the laboratory parameters measured.

Pharmacokinetics of the anti-inflammatory drug ximoprofen in healthy young and elderly subjects: comparison with elderly rheumatic patients

The pharmacokinetics of ximoprofen were studied in young and elderly subjects after single and repeated doses up to 30 mg. In healthy elderly subjects (30 mg dose), a mean peak plasma drug concentration of 1.78 micrograms ml-1 +/- 0.83 s.d. occurred at a mean time of 1.95 h +/- 1.40 s.d. and, thereafter, concentrations declined monoexponentially with a mean half-life of 3.8 h +/- 1.4 s.d. Comparison of these data with those from younger healthy subjects showed that peak drug concentrations, areas under the curve and half-lives were about two-fold greater in the elderly, these differences probably reflecting a lower systemic drug clearance. Similar results were obtained on comparing data from young healthy subjects and elderly rheumatic patients receiving single and repeated doses of ximoprofen (15 mg twice daily). In patients, the half-life of ximoprofen was 2.5 h +/- 0.7 s.d. Within either group, pharmacokinetic parameters after single or repeated doses were similar: ximoprofen did not accumulate in the plasma of the young or elderly.

Thyrotropin-releasing hormone regulation of human TSHB expression: role of a pituitary-specific transcription factor (Pit-1/GHF-1) and potential interaction with a thyroid hormone-inhibitory element

Regulation of human thyrotropin beta subunit gene (TSHB) expression by thyrotropin-releasing hormone (TRH) was examined in a clonal rat pituitary-cell line (GH3). Transient expression studies were done with various 5'-flanking DNA sequences of TSHB coupled to reporter gene chloramphenicol acetyltransferase. Deletion analysis defined two discrete regions (-128 to -92 base pairs and -28 to +8 base pairs) that each mediated an approximately 2-fold TRH induction. The upstream site contains a DNA sequence with close homology to the DNA-binding site for a pituitary-specific transcriptional factor Pit-1/GHF-1. DNase I footprinting analysis of mouse thyrotropic tumor extract as well as DNA-transfection studies using an expression vector containing an N-terminal deletion of Pit-1/GHF-1 cDNA suggest that Pit-1/GHF-1 or a closely related protein in the thyrotroph mediates TRH responsiveness of this gene. In addition, the downstream site overlaps with the recently characterized thyroid hormone-inhibitory element of TSHB. In fact, deletion of DNA sequences important in thyroid hormone-receptor binding (c-erbAB/c-ERBA2) from +3 to +8 base pairs, significantly reduced (30%) TRH responsiveness. The location of a TRH-stimulatory element near a thyroid hormone-inhibitory element may allow for fine control of TSHB expression in vivo.

Pharmacokinetics of pyridostigmine in dogs

The pharmacokinetics of the cholinesterase inhibitor pyridostigmine has been studied in six male Beagle dogs after iv infusion and after oral doses as an immediate-release syrup and as an extended-release tablet, all at a level of approximately 0.6 mg/kg. Pyridostigmine was characterized as a drug of relatively long terminal half-life (8.3 h +/- 2.1 SD), low systemic clearance (13 mL/min/kg +/- 1 SD) and high volumes of distribution (Vd lambda z, 8.7 L/kg +/- 1.9 SD and Vdss, 3.9 L/kg +/- 0.9 SD). The ratio of mean residence times in tissues and plasma was greater than 4, indicating a high affinity of peripheral tissues for the drug. This ratio was about twofold higher in three of the dogs than in the others. Pyridostigmine was slowly and incompletely bioavailable in these dogs; the systemic availability was 44.4% +/- 4.3 SD from the syrup and 33.6% +/- 9.5 SD from the tablet. Pyridostigmine disposition in these dogs was largely determined by distribution processes.

Pharmacokinetics of the anti-inflammatory drug ximoprofen in healthy subjects and in disease states

The pharmacokinetics of ximoprofen, a potent new non-steroidal anti-inflammatory agent, has been investigated in normal healthy subjects and in patients with hepatic or renal disease. After intravenous infusion of 22.8 mg to healthy subjects, plasma ximoprofen concentrations declined in a polyexponential manner with a terminal phase half-life of 1.9 h. The systemic clearance of ximoprofen was 115 ml.min-1 and the volumes of distribution were 18.01 Vz and 13.81 Vss. Ximoprofen was 80-90% bound to plasma proteins. The systemic availabilities (f) of orally and rectally administered doses of 30 mg of ximoprofen were 98% and 56% respectively and, in the case of the rectal dose, absorption appeared to be prolonged leading to "flip-flop" kinetics. After single oral doses of 30 mg of ximoprofen to patients with hepatic disease, half-life (2.2 h), peak plasma concentrations (1.55 micrograms.ml-1 cf 1.04 micrograms.ml-1 in healthy subjects) and areas under the curve (6.12 micrograms.h.ml-1 cf 3.54 micrograms.h.ml-1 in healthy subjects) were significantly different from those in healthy subjects. After single oral doses of 30 mg of ximoprofen to patients with renal disease, pharmacokinetic parameters of half-life (4.0 h), mean residence time (6.0 h) and area under the curve (9.2 micrograms.h.ml-1) were significantly different from those in healthy subjects. There were no significant differences in pharmacokinetic parameters between patients having differing degrees of renal disease. These data nevertheless suggest that accumulation of ximoprofen in hepatic or renal disease would be of slight or negligible clinical relevance and that no alteration of the dose regimen (up to 15 mg twice daily) may be required when ximoprofen is administered in these disease states.

Effects of hysterectomy on bowel and bladder function

A case control study compared the bowel habit of 91 post-hysterectomy women with paired controls from the same family doctor practice. More cases had an abnormal bowel frequency, a firmer stool consistency and assessed themselves as having abnormal bowel function, predominantly constipation after hysterectomy, than controls. Significantly more cases than controls had consulted a doctor because of constipation but there was no significant difference in laxative usage. There was a significant short-term association between decreased bowel frequency and increased urinary frequency after hysterectomy. This became highly significant in those patients who developed chronic symptoms. Oophorectomy, unilateral or bilateral, did not significantly affect bowel habit other than to intensify the change in stool consistency. The hypothesis is discussed that the post-hysterectomy effects on bowel and bladder function may have a common aetiology in a degree of autonomic denervation of both viscera.

Genomic maps of some strains within the Mycoplasma mycoides cluster

Genomic restriction maps for the small colony (SC) strains (PG1, KH3J, Gladysdale, and V5) of Mycoplasma mycoides subsp. mycoides (the agent of contagious bovine pleuropneumonia) and for Mycoplasma strain PG50 (classified as bovine serogroup 7), with respective sizes of 1,280, 1,280, 1,260, 1,230, and 1,040 kbp, were compared with the map (1,200 kbp) for a large colony strain (Y goat) of M. mycoides subsp. mycoides. The number and order of all mapped restriction sites were fully conserved in the SC genomes, as were the approximate positions of mapped loci. A number of these restriction sites in the Y genome and some, but fewer, in the PG50 genome appeared to be conserved. The SC and large colony strains shared conservation in the relative positions of the mapped loci, except for rpoC.

Thyroid hormone regulation of TRH mRNA levels in rat paraventricular nucleus of the hypothalamus changes during ontogeny

The changing roles of the hypothalamus and pituitary in regulating thyroid hormone levels in the rat during ontogeny has not been fully elucidated. It has been reported that endogenous TRH begins to stimulate TSH secretion at 5-8 days after birth but that the pituitary responds to hypothyroidism during late gestation. To determine the onset and extent of TRH response to low thyroid hormone levels during ontogeny, normal and hypothyroid rats treated with methimazole for 7 days were sacrificed at 16 days gestation (E16), 20 days gestation (E20), 7, 21 and 56 days after birth (n = 5/study group). Plasma hormones were assayed from pregnant mothers, pups (pooled) and adults. Levels of TRH mRNA were measured in the paraventricular nuclei (PVN) by in situ hybridization histochemistry. A labeled 48-base cDNA oligonucleotide for TRH was hybridized with brain slices (n = 6/animal) in the region of the medial parvocellular division of the PVN of the hypothalamus and the signal was quantitated by digitized computer analysis. Plasma-free T4 levels decreased and plasma TSH levels increased in the animals treated with methimazole as compared to the euthyroid controls. TRH mRNA was detected in the PVN at E16 after brain slices were dipped in emulsion and granules observed by dark-field microscopy. In the euthyroid animals, TRH mRNA increased from E20 (150 +/- 9 OD units) to 7 days (222 +/- 5 OD units) and remained unchanged at 21 days (252 +/- 27 OD units) and 56 days (244 +/- 6 OD units).(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of the 32.5 kDa protein from the venom of an endoparasitic wasp

The major venom proteins from the endoparasitic wasp were analyzed for distribution in the venom gland. A 32.5 kDa protein was purified from the venom gland of the Chelonus near curvimaculatus wasp. The protein accounts for about 25% of the total protein content of the venom and each gland contains 3-6 pmol of this component. The protein is acidic in nature and anion-exchange chromatography facilitated the purification of the protein to apparent homogeneity. On testing the purified protein by in vivo bioassay, it was found to elicit an effect comparable with the complete venom. The protein does not appear to have any disulfide bonds of major structural importance exposed under SDS-denaturing conditions. Products of chemical partial digest of the purified protein at the methionyl residues by cyanogen bromide were analyzed by SDS-PAGE. The 27.6 kDa fragment retained an epitope to an antibody raised against total Chelonus venom proteins, whereas no epitopes were detected for 4.9 and 0.6 kDa fragments.

Determination of benzydamine and its N-oxide in biological fluids by high-performance liquid chromatography

A simple, sensitive and selective method for the determination of benzydamine in human plasma and urine, and for benzydamine N-oxide in urine, has been developed using high-performance liquid chromatography in the reversed-phase mode. The limit of reliable determination of benzydamine in plasma was 0.5 ng/ml and that in urine 1 ng/ml; the limit of reliable determination of benzydamine N-oxide in urine was 50 ng/ml. The method has been successfully applied to the analysis of these compounds in biological fluids after administration of intravenous and oral doses of benzydamine to human volunteers.

Preventing complications from hemodialysis

Hemodialysis is a complex procedure requiring the most skilled nurses. Critically ill patients who undergo hemodialysis are at a greater risk of cardiovascular, circulatory, electrolyte, neurologic, and other complications. The critical care nurse helps prevent or reduce these complications.

The paraventricular nucleus of the hypothalamus has a major role in thyroid hormone feedback regulation of thyrotropin synthesis and secretion

The role of the hypothalamic paraventricular nucleus (PVN) in thyroid hormone regulation of TSH synthesis during hypothyroidism was studied in adult male rats that were normal (n = 10), had primary hypothyroidism with sham lesions in the hypothalamus (n = 17), and had primary hypothyroidism with PVN lesions (n = 14). Two and 4 weeks after initiation of treatment, plasma levels of thyroid hormones (TSH, corticosterone and PRL) and pituitary content of TSH beta and alpha-subunit mRNA were measured. TRH mRNA levels in the PVN were determined by in situ hybridization histochemistry. At 2 weeks, despite a decrease in plasma free T4 in both hypothyroid groups, plasma TSH levels increased, but to a lesser degree, in the hypothyroid PVN lesioned compared to hypothyroid sham-lesioned group (7.8 +/- 1.3 vs. 20.5 +/- 1.1 ng/dl; P less than 0.05). Similarly, at 4 weeks, the hypothyroid PVN-lesioned group demonstrated a blunted TSH response compared to the hypothyroid sham-lesioned group (6.8 +/- 0.7 vs. 24.0 +/- 1.3 ng/dl; P less than 0.05). Plasma corticosterone and PRL did not significantly differ between sham-lesioned and PVN-lesioned groups. TSH beta mRNA levels markedly increased in hypothyroid sham-lesioned rats compared to those in euthyroid controls at 2 weeks (476 +/- 21% vs. 100 +/- 39%; P less than 0.05) and 4 weeks (1680 +/- 270% vs. 100 +/- 35%; P less than 0.05). In contrast, TSH beta mRNA levels did not increase with hypothyroidism in the PVN-lesioned group compared to those in euthyroid controls at 2 weeks (140 +/- 16%, P = NS) and only partially increased at 4 weeks (507 +/- 135; P less than 0.05). alpha mRNA levels at 4 weeks markedly increased in hypothyroid sham-lesioned rats compared to those in euthyroid controls (1121 +/- 226% vs. 100 +/- 48%; P less than 0.05), but did not increase in the hypothyroid PVN-lesioned rats (61 +/- 15%; P = NS). TRH mRNA in the PVN increased in the hypothyroid sham-lesioned rats compared to those in euthyroid controls (16.6 +/- 1.3 vs. 4.8 +/- 1.2 arbitrary densitometric units; P less than 0.05), and TRH mRNA was not detectable in the PVN of hypothyroid-lesioned rats at 2 weeks. In summary, lesions in rat PVN prevented the full increase in plasma TSH, pituitary TSH beta mRNA, and alpha mRNA levels in response to hypothyroidism. Thus, factors in the PVN are important in thyroid hormone feedback regulation of both TSH synthesis and secretion.

Multiple forms of pancreatic polypeptide-related compounds in the lamprey CNS: partial characterization and immunohistochemical localization in the brain stem and spinal cord

Although neuropeptide Y (NPY) is established as a transmitter in many regions of the nervous system, the role of other peptides of the pancreatic polypeptide (PP) family in the CNS is obscure. This study provides evidence that PP-like peptides in the "primitive" CNS of a cyclostome are composed of different molecular forms, which are stored in separate neuronal populations with apparently different functions. PP-like material was detected in extracts of brain and spinal cord from Lampetra fluviatilis by radioimmunoassay (RIA) using an antiserum to the C-terminal hexapeptide of mammalian PP. The PP-immunoreactive material consisted of several molecular forms, as shown by its complex elution profile on high-performance liquid chromatography (HPLC). The cellular distribution of PP-like immunoreactivity was studied with indirect immunofluorescence histochemistry using antisera toward porcine peptide YY (PYY), porcine neuropeptide Y (NPY), and bovine (BPP), rat (RPP), and avian (APP) pancreatic polypeptide. Adjacent sections from the brain stem and spinal cord of L. fluviatilis and Ichthyomyzon unicuspis, incubated with the different antisera, displayed 2 main patterns of PP immunoreactivity. The PYY and RPP antisera labeled groups of neurons and fibers in the rhombencephalic and mesencephalic reticular formation. One of the PYY/RPP-ir cell groups, located in the anterior rhombencephalic reticular nucleus, had a projection to the dorsolateral spinal cord. Fibers of this reticulospinal system were in close apposition to dendrites of intracellularly stained spinal motoneurons and sensory relay interneurons, indicating that they may receive PPergic input. In contrast, antisera to NPY and APP labeled local neurons systems in the spinal dorsal horn, in the lateral parts of the brain stem, including the rhombencephalic alar plate, and in the retina. The BPP antiserum recognized the NPY/APP as well as the PYY/RPP immunoreactive neuron systems, further supporting that they both contain PP-like peptides.

The fetal rat binding protein for insulin-like growth factors is expressed in the choroid plexus and cerebrospinal fluid of adult rats

The biological effects of the insulin-like growth factors, IGF-I and IGF-II, on their receptors are modulated by IGF-binding proteins. Recently, we isolated a cDNA clone for one member of the family of IGF-binding proteins, BP-3A, a 30 kilodalton (kDa) protein synthesized by the BRL-3A rat liver cell line. BP-3A is related to but distinct from two other cloned IGF-binding proteins, the human amniotic fluid binding protein and the glycosylated binding subunit of the 150 kDa IGF-binding protein complex in serum. It is expressed in multiple nonneural tissues and in serum in the fetal rat and decreases after birth, similar to the developmental pattern of IGF-II expression. IGF-I, IGF-II, and their receptors are expressed in brain. The present study examines the expression of BP-3A in the rat central nervous system. By Northern blot analysis, BP-3A mRNA is present at high levels in brain stem, cerebral cortex, and hypothalamus from 21-day gestation rats and, like IGF-II mRNA, persists in adult rat brain. The site of BP-3A mRNA synthesis was localized by in situ hybridization to coronal sections of adult rat brain using 35S-labeled oligonucleotides, 48 bases in length, complementary and anticomplementary to the coding region of BP-3A. Specific hybridization of the BP-3A probe was observed exclusively to the choroid plexus extending from the level of the medial preoptic nucleus to the arcuate nucleus of the hypothalamus, similar to the previously reported preferential localization of IGF-II mRNA to the choroid plexus. Synthesis of BP-3A mRNA by choroid plexus suggested that BP-3A might be secreted into the cerebrospinal fluid. A 30 kDa IGF-binding protein was demonstrated in rat cerebrospinal fluid that is recognized by antibodies to BP-3A and, like purified BP-3A, has equal affinity for IGF-I and IGF-II. By analogy with other transport proteins synthesized by the choroid plexus, BP-3A may facilitate the secretion of IGF-II to the cerebrospinal fluid and modulate its biological actions at distant sites within the brain.

Altered thyrotropin (TSH) carbohydrate structures in hypothalamic hypothyroidism created by paraventricular nuclear lesions are corrected by in vivo TSH-releasing hormone administration

TSH is a glycoprotein hormone composed of two subunits with attached carbohydrate chains that have varying structural characteristics. To determine the role of TRH in vivo in regulating structural characteristics of TSH carbohydrate chains, adult rats received paraventricular nuclear (PVN) lesions (n = 6) or sham lesions (n = 6). The PVN contain large amounts of TRH, and rats with lesions in these hypothalamic nuclei have been shown to have decreased plasma thyroid hormone levels. At 10 days after surgery, sc osmotic pumps infusing saline or 1 mg/kg/day TRH were placed. At 14 days after surgery, pituitaries were removed and incubated with [3H]glucosamine for 24 h. Glycopeptides prepared from secreted TSH were sequentially eluted from Concanavalin-A chromatography columns selecting unbound, weakly bound, and strongly bound forms. Plasma free T4 was lower in the PVN lesioned rats treated with saline than sham lesioned rats treated with saline (1.6 +/- 0.4 vs. 5.2 +/- 0.1 ng/dl, P less than 0.001). In vivo TRH administration in the PVN lesioned group normalized plasma free T4 but had no effect on free T4 in the sham group. Secreted TSH glycopeptides in the PVN lesioned rats treated with saline as compared to sham lesioned rats treated with saline had fewer unbound forms reflecting multiantennary structures (43 +/- 4 vs. 57 +/- 1%; P less than 0.05) and more weakly bound forms reflecting biantennary structures (50 +/- 4 vs. 35 +/- 2%; P less than 0.05). TRH administration in vivo normalized the Concanavalin-A binding pattern of secreted TSH glycopeptides in the PVN lesioned group but had no significant effect in the sham lesioned group. TSH alpha-subunit demonstrated both multi- and biantennary forms but TSH-beta subunit showed a predominance of multiantennary forms in both the PVN and sham lesioned groups treated with saline. In vivo changes in TRH levels altered TSH carbohydrate characteristics as described above for both subunits. In summary, hypothalamic hypothyroidism altered TSH carbohydrate structures, and in vivo TRH administration normalized these structures in parallel with the correction of serum free T4. In addition to reported quantitative changes in TSH in response to TRH, these qualitative changes may have an important effect on TSH action.

Absorption of amlodipine unaffected by food. Solid dose equivalent to solution dose

The oral bioavailability of amlodipine in healthy volunteers was compared in two separate studies after solution and capsule doses, and after capsule doses in fed and fasting states. The bioavailability of amlodipine was equivalent both in terms of rate and in extent of absorption between solution and capsule doses and in the fed and fasting states.