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.

Ontogeny of thyrotropin-releasing hormone gene expression in the rat diencephalon

The development of thyrotropin-releasing hormone (TRH) gene expression in the rat diencephalon was studied using in situ hybridization histochemistry. The first neurons expressing the TRH gene were found on gestational day 14 (E14) in the lateral hypothalamus, shortly after completion of their last cell division. On E15 and E16, additional labeled cells appeared medially in the developing dorsomedial and paraventricular nuclei, respectively, followed on E17 by cells in the preoptic area. The number of labeled cells in the hypothalamus continued to increase during the last part of gestation. At birth, TRH mRNA neurons were present in all the locations seen in the adult hypothalamus. During the first week of life, the labeling intensity and number of neurons containing TRH mRNA continued to increase at the locations described above. TRH mRNA was not detected in the reticular thalamic nucleus until the 7th postnatal day when some labeled cells appeared in its dorsocaudal portion. Over the next 10 days, the number of labeled cells and the intensity of labeling in the thalamic reticular nucleus progressively increased. During the same period of time, only small changes in the number and intensity of labeled cells in the hypothalamus were seen. On the 21st postnatal day, after a decrease in labeling in the lateral hypothalamus had been noted, final adult patterns of expression were present. With the very sensitive and anatomically specific method of in situ hybridization histochemistry, the ontogeny of TRH gene expression in the rat diencephalon has been elucidated.

Prolonged converting enzyme inhibition in non-modulating hypertension

Patients with normal- or high-renin non-modulating essential hypertension fail to shift their adrenal sensitivity on a low sodium diet in response to an infusion of angiotensin II (Ang II). In a prior study, 72 hours of converting enzyme inhibition (CEI) partially corrected this subnormal aldosterone response to Ang II in patients with non-modulating hypertension. Since it was uncertain whether the failure to restore normal adrenal responsiveness reflected a continued abnormality or an insufficient duration of CEI, the present study was performed wherein subjects were studied before CEI and then 72 hours and 6 weeks after CEI. Adrenal and renovascular responses were assessed in 13 subjects with normal- or high-renin hypertension in response to an infusion of Ang II (0.3, 1.0, and 3.0 ng/kg/min) in balance on a 10 meq Na+/100 meq K+ diet. Eight of 13 had a normal plasma aldosterone increment above control levels (greater than or equal to 15 ng/dl) and were classified as modulators; the remaining subjects (five of 13) were classified as non-modulators. Enalapril was then administered for 72 hours and 6 weeks, and the assessment of the Ang II dose-response relations was repeated. In the modulators, there was no change compared with levels before CEI in the aldosterone dose-response curve or threshold sensitivity to infused Ang II at either 3 days or 6 weeks after CEI administration. In the non-modulators, CEI for 72 hours partially restored aldosterone responsiveness, but more prolonged CEI for 6 weeks completely corrected the defect, restoring aldosterone responsiveness on a sodium-restricted diet to that seen in modulators and in normotensive control subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum erythropoietic activity in acute anemia--an animal model

Serum erythropoietic activity and reticulocyte response to anemia were investigated using a rabbit model. In hemolytic anemia, induced by injections of phenylhydrazine on Day 0 the hemoglobin reached a nadir (mean, 6.23 g/dl) on Day 4 when SEA was maximal (mean, 765 mU/ml). In animals venesected on Day 0 and Day 1 to produce anemia of equal severity, the SEA was maximal (mean 235 mU/ml) on Day 2. In both groups the reticulocyte response peaked on Day 7--at 34% for the hemolytic group and 21% for the venesected group. The 2,3-diphosphoglycerate, measured on Day 4, was significantly reduced in the PHZ-treated group. In the venesected group the 2,3-DPG increased between Day 0 and Day 4. There were no concurrent changes in acid-base balance. These results imply that the degree of anemia is only one of the factors which influence the level of circulating SEA.

M-VAC or MVC for the treatment of advanced transitional cell carcinoma: metastatic, induction, and adjuvant

The cisplatin-based combination chemotherapy regimens of M-VAC (methotrexate, vinblastine, doxorubicin, cisplatin) or MVC (methotrexate, vincristine, cisplatin) were given to 25 patients with metastatic urothelial carcinoma, 13 with locally advanced bladder cancer, and 10 as adjuvant therapy after radical surgery. Toxicity was significant with two deaths. Forty-eight percent of the patients with metastatic disease had a complete (20%) or partial (28%) response. Survival was only improved if a CR was achieved. Nine of 13 patients given M-VAC/MVC as neoadjuvant therapy underwent cystectomy and six are free of disease (mean 31 months). Three of the four patients who did not have radical surgery are also free of disease. These regimens appear to be superior to cisplatin alone. In the overall response evaluation, however, toxicity is greater.

Pre-translational and post-translational regulation of TSH synthesis in normal and neoplastic thyrotrophs

We are interested in the mechanisms by which endocrine and developmental factors regulate TSH synthesis at both pre-translational and post-translational levels. Thyroid hormone profoundly decreases transcription of the TSH-beta gene, while TRH and agents modifying cyclic AMP increase transcription. To elucidate the molecular mechanisms underlying these effects, human embryonal kidney cells were transfected with constructs of the human TSH-beta gene fused to the chloramphenicol acetyltransferase gene. The first exon of human TSH-beta, contains an element that increases basal expression and mediates T3-induced gene repression, probably through a direct interaction with c-erbA beta. This transcriptional repression by T3 appears aberrant in thyrotropic tumors. In contrast, TRH and agents modifying cyclic AMP mediate increased transcription of TSH-beta through interacting with upstream regulatory elements. Thyroid hormone, TRH and developmental factors also regulate the branching pattern and relative sialylation of TSH carbohydrate chains, which may affect TSH action in vitro and in vivo. Certain thyrotropic tumors produce TSH with more complex carbohydrate branching patterns, which may increase its biologic activity.

Measurement of theophylline in dried blood spots by spectrophotometric enzyme immunoassay

A widely-used enzyme immunoassay for the measurement of theophylline in plasma (EMIT) has been adapted for use with dried blood spots. Potential interference from haemoglobin in eluates of the spots was avoided by autoclaving them prior to analysis. The method was investigated in terms of the recovery of theophylline added to samples, precision, and the correlation of results in DBS with those in plasma samples. The recoveries of some other drugs from eluates of autoclaved DBS were also investigated.

Comparison of the mouse spleen cell assay and a radioimmunoassay for the measurement of serum erythropoietin

The mouse spleen cell assay (MSCA) has been compared with a radioimmunoassay for the measurement of serum erythropoietin (Ep). In 20 normal subjects the serum values ranged from 15 to 73 mU/ml for the MSCA compared with 5-30 mU/ml for the RIA. For normal sera there was no correlation between the results of the two assays. In 37 patients with anaemias of differing aetiologies and at various stages of treatment values ranged from 10 to 3645 mU/ml for the MSCA and 13-10,000 mU/ml for the RIA. Although patient values from the two assays were highly correlated (r = 0.98, P less than 0.001), the MSCA results were generally lower. These discrepancies can be largely accounted for by two factors. Firstly the MSCA is sensitive to non-specific matrix effects. Secondly, heat inactivation of serum, a prerequisite for the MSCA, but not for the RIA, destroys a variable and unpredictable proportion of the Ep in the test sera leading to an underestimation of Ep in the MSCA. We conclude that the RIA is more reliable than the MSCA which, in its present form, cannot be recommended for the accurate measurement of serum erythropoietin.

Hypothalamic hypothyroidism caused by lesions in rat paraventricular nuclei alters the carbohydrate structure of secreted thyrotropin

The effects of hypothalamic hypothyroidism vs. primary hypothyroidism on TSH carbohydrate structure were studied in the rat. Adult male rats with bilateral paraventricular nuclear lesions (n = 10), sham lesions (n = 10), and thyroidectomies (n = 6) were studied 2 weeks postoperatively and compared to normal animals without surgery (n = 6). Pituitaries were incubated in medium containing [3H]glucosamine for 24 h. TSH was immunoprecipitated from medium and pituitary sonicates using anti-TSH beta serum, digested with pronase to obtain TSH glycopeptides, desalted, then analyzed by Concanavalin-A (Con-A) chromatography. Compared to sham controls, hypothalamus-lesioned animals contained a greater proportion of secreted TSH glycopeptides that bound weakly to Con-A, indicating a shift from bisecting and/or multiantennary structures in control animals to biantennary and/or truncated hybrid forms in hypothalamus-lesioned animals. In contrast, thyroidectomized animals, compared to normal and lesioned animals, contained a greater proportion of secreted TSH glycopeptides that did not bind to Con-A, indicating a shift from biantennary and/or truncated hybrid forms to bisecting and/or multiantennary forms. The characteristics of the carbohydrate chains on secreted TSH differed markedly in hypothalamic vs. primary hypothyroidism despite equally low thyroid hormone levels in vivo. Thus, in addition to regulating TSH secretion, hypothalamic hormones alter TSH carbohydrate structure, which may affect its bioactivity and MCR.

Acute pancreatitis and primary hyperparathyroidism in pregnancy: treatment of hypercalcemia with magnesium sulfate

A patient is described in whom intravenous magnesium sulfate, administered for preeclampsia, successfully treated hypercalcemia associated with hyperparathyroidism. This single case suggests that magnesium sulfate might be an effective alternative to standard medical or surgical treatment of this condition.

Changes in thyrotropin (TSH) carbohydrate structure and response to TSH-releasing hormone during postnatal ontogeny: analysis by concanavalin-A chromatography

We have studied the carbohydrate structure of TSH as well as its response to TRH during postnatal ontogenesis in the rat using Concanavalin-A (Con A)-Sepharose chromatography of labeled glycopeptides. Pituitaries from neonatal (5-day-old) rats with low levels of endogenous TRH and mature (56-day-old) rats were incubated for 24 h in medium containing [3H] glucosamine in the presence or absence of 10(-7) M TRH. Both intracellular and secreted TSH were immunoprecipitated, treated with Pronase to generate glycopeptides, and analyzed by chromatography on Con A-Sepharose. The total amount of [3H]glucosamine-labeled TSH was greater per pituitary in mature rats compared to that in neonatal rats (P less than 0.05), while there was no significant difference between the groups in the concentration of total labeled TSH per microgram pituitary DNA. RIA determination of total TSH was greater in the older animals than in the younger animals when normalized both per pituitary and per microgram pituitary DNA (P less than 0.01 and P less than 0.02, respectively). However, for both labeled and unlabeled TSH the percentage of TSH secreted was greater in mature rats than in neonatal rats (P less than 0.02 and P less than 0.01, respectively), indicating a less active hormonal secretory process in the younger animals. In control animals, the proportion of labeled TSH glycopeptides that did not bind to Con A was greater in 56- than in 5-day-old animals for both intrapituitary and secreted forms (P less than 0.01), reflecting a shift toward more multiantennary and/or bisected biantennary complex carbohydrate structures in the older animals. In response to TRH in vitro, the total amount of labeled secreted TSH was increased more than 2-fold in both 5-day-old (P less than 0.05) and 56-day-old (P = NS) animals. However, there was a marked difference in the glycopeptide distribution between these two ages. Five-day-old animals showed a small but not significant decrease in the percentage of secreted TSH glycopeptides that bound to Con A-Sepharose, while 56-day-old animals had a specific increase in the glycopeptide fractions that bound and corresponded to biantennary complex and/or unusual hybrid forms (P less than 0.01). These studies in the rat suggest differences in TSH carbohydrate structure and secretion as well as a differential response to TRH during postnatal ontogenesis.

Modulation of testicular galactolipid sulfotransferase activity in vitro by ATP

Testicular galactolipid sulfotransferase activity is an early marker of differentiation during mammalian spermatogenesis. The enzyme will catalyze the sulfation of galactosylglycerol in the 3' position of the galactose moiety at 37 degrees C in vitro. However, sulfotransferase activity was found to be completely lost on preincubation of the solubilized enzyme preparation at 37 degrees C. This loss of activity was completely prevented by inclusion of ATP and Triton in the preincubation step. This protective effect was synergistic, pH dependent and correlated with an inhibition of endogenous phosphatase activity. These results are interpreted to suggest that the galactolipid sulfotransferase may be regulated by a phosphorylation mechanism.

Systemic administration of glycosaminoglycan polysulphate (arteparon) provides partial protection of articular cartilage from damage produced by meniscectomy in the canine

Bilateral medial meniscectomy was undertaken in 14 mature beagles. Another two underwent arthrotomy (sham-operated controls). One week after surgery, six of the meniscectomised animals were administered glycosaminoglycan polysulphate (Arteparon) (2 mg/kg) subcutaneously three times a week for 3 weeks, then twice weekly until killed 23 weeks later. Two months before death all animals were given Na2(35)SO4 (1.0 mCi/kg) intravenously. At autopsy, articular cartilage (AC) from the medial and lateral compartments, as well as from the femoral trochlear groove and femoral head, was sampled. Proteoglycans (PGs) were isolated by 4.0 M Guanidine hydrochloride (GuHCl) extraction of AC and purified by ultracentrifugation. The PG monomers were assayed for hexuronic acid, protein, and hexosamines (galactosamine/glucosamine), and their ability to aggregate. The results indicated that Arteparon provided some protective effect to AC in the meniscectomised compartment as demonstrated histologically by reduced surface fibrillation, diminished chondrocyte cloning, and maintenance of alcianophilia. The levels of PGs and hexuronate-protein ratios in medial AC of drug-treated meniscectomised animals were found to be comparable to sham controls, whereas these parameters in the nondrug-treated meniscectomized group were depressed.

Customers versus patients. A marketing perspective on health care

The thrust of health care "solutions" in the press and in Congress focus on the infirm. In fact, it is the only segment where all of the various economic models fit well. Considerable marketing planning and implementation techniques must be brought to bear on solutions for the healthy, the worried, and the early sick segments in the near future.

High-performance liquid chromatographic fractionation and partial characterization of cystic fibrosis serum ultrafiltrates

Analytical separation of serum ultrafiltrates by high-performance liquid chromatography produces a distinctive peak with a retention time of 18.5-21 min (subfraction 18.5) from cystic fibrosis serum ultrafiltrates and obligate heterozygote serum ultrafiltrates, but not in significant concentrations from control or asthmatic serum ultrafiltrates. Semipreparative separation of control serum ultrafiltrates produced a small peak with similar retention time that was approximately 1% of the arbitrary absorbance units found in this cystic fibrosis subfraction. Subfraction 18.5 had biological activity only when separated from cystic fibrosis serum ultrafiltrate, but did not contain measurable amounts of C3a des-arginine and C4a des-arginine. Subfraction 18.5 is a low-molecular-weight material (1000-1400 daltons) that contains 14.9 micrograms orcinol positive material per 50 micrograms protein. The spectrum of subfraction 18.5 indicates that it has to be purified to homogeneity.

Effects of in vivo bolus versus continuous TRH administration on TSH secretion, biosynthesis, and glycosylation in normal and hypothyroid rats

The effects of in vivo TRH administered either as bolus or continuous doses on TSH secretion, synthesis, and glycosylation were studied in normal and hypothyroid rats. Nine-week-old normal or 3-week postthyroidectomy rats were administered bolus doses of saline or TRH (0.5 mg/kg) twice daily or continuous saline or TRH (1 mg/kg/day) via an osmotic pump. After 5 days, pituitaries were removed and incubated with [35S]methionine (MET) and [3H]glucosamine (GLCN), with or without 10(-8) M TRH, for 6 and 24 h. Samples were precipitated with anti-TSH beta sera and then analyzed by gel electrophoresis. In normal rats, plasma TSH, T4 and T3 increased with continuous in vivo TRH but not with bolus TRH; in hypothyroid rats, plasma TSH, T4 and T3 were not altered by continuous or bolus doses of TRH. Additionally, in normal rats, continuous in vivo TRH increased incorporation of MET in secreted TSH (477 vs. 212 X 10(3) dpm/mg DNA; P less than 0.05) and intrapituitary TSH (5035 vs. 2124 X 10(3) dpm/mg DNA; P less than 0.05), and GLCN in secreted TSH (148 vs. 50 dpm/mg DNA; P less than 0.05) and intrapituitary TSH (2344 vs. 744 X 10(3) dpm/mg DNA; P less than 0.05). In contrast, in hypothyroid animals, continuous in vivo TRH did not alter MET or GLCN incorporation in TSH. Bolus TRH did not alter secreted or intrapituitary MET or GLCN incorporation into TSH in the normal rat. However, bolus TRH in the intrapituitary MET or GLCN incorporation into TSH in the normal rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma concentrations and relative bioavailability of naftidrofuryl from different salt forms

The relative bioavailability of the vasodilator naftidrofuryl from formulations containing its oxalate or citrate salt has been estimated using a specific HPLC assay, and a less specific fluorimetric assay, to measure plasma drug concentrations. The conclusions of the study were the same irrespective of the assay employed. The relative rate, but not the extent, of bioavailability of naftidrofuryl from the citrate salt (peak 1096 ng ml-1 at 0.76 h) was marginally greater (p = 0.003) than that from the oxalate salt (peak 922 ng ml-1 at 0.94 h). The degree of intersubject variability was similar after administration of either salt form. The mean half-life of naftidrofuryl was 1.8 h and its mean residence time was 2.5 h.

Synthesis and use of galactolipid sulfotransferase substrate-analogue affinity probes: possible localization of the testicular enzyme

Galactosyl ceramide (GC) is a substrate in vitro for galactolipid sulfotransferase preparations from brain, kidney, and testis. Biotinylated and light-sensitive azido derivatives of lysogalactosyl ceramide have been synthesized. These derivatives remain effective substrates for the testicular enzyme. Biotinylated GC has been used to localize specific GC-binding sites in frozen sections of rat testis. The binding pattern is consistent with the expected location of the testicular galactolipid sulfotransferase.

Regulation of renal sulfoglycolipid biosynthesis

The in vitro activity of the renal galactolipid sulfotransferase and the level of sulfated glycolipids in the rat kidney have been correlated as a function of age. The galactolipid sulfotransferase was found to be greatly reduced in the young as compared with the adult animal. The relatively minor changes in the sulfated glycolipid content of the kidney with age suggests that an increase in sulfoglycolipid turnover occurs during growth. An inhibitory activity was detected in the homogenate supernate of the young animal capable of reducing the in vitro sulfotransferase activity of the adult. Assay of the human renal galactolipid sulfotransferase showed that this enzyme activity is deleted in samples of the blastematous form of Wilm's renal tumor. The results suggest that the rate of synthesis of renal sulfoglycolipids may prove a marker of renal development, perhaps by post translational regulation.

The effects of anterior hypothalamic deafferentation on thyrotropin (TSH) biosynthesis and response to TSH-releasing hormone

The effects of hypothalamic deafferentation on TSH synthesis were studied by making cuts of 180 degrees arc in the anterior hypothalamus (n = 18) or sham cuts (n = 12) in rats. After 21 days, pituitaries were incubated with [35S]methionine (MET), [3H]glucosamine (GLCN), with or without 10(-8)M TRH for 24 h. TSH and free alpha-subunits were immunoprecipitated and analyzed by gel electrophoresis. In the deafferented group as compared to sham, MET incorporation into both subunits of secreted TSH was decreased (alpha, 96 +/- (SE) 9 X 10(3) vs. 180 +/- 20 X 10(3) dpm/mg protein; beta, 35 +/- 9 X 10(3) vs. 84 +/- 15 X 10(3) dpm/mg protein; P less than 0.05). Basal GLCN incorporation into both subunits of secreted TSH was also decreased in the deafferented group (alpha, 6.5 +/- 11 X 10(3) vs. 132 +/- 17 X 10(3) dpm/mg protein; beta, 36 +/- 8 X 10(3) vs. 101 +/- 29 X 10(3), P less than 0.05). In vitro TRH did not stimulate MET incorporation into secreted TSH in the sham controls but did in the deafferented group (alpha, 270% of basal; beta, 374% of basal; P less than 0.01). In vitro TRH increased GLCN incorporation in secreted TSH in both the sham (alpha, 253% of basal; beta, 245% of basal; P less than 0.02) and the deafferented group (alpha, 692% of basal; beta, 630% of basal; P less than 0.01). GLCN/MET ratio, reflecting relative glycosylation, did not differ for sham or deafferented groups but increased 2-fold with in vitro TRH in each group for both secreted subunits (P less than 0.01). Free alpha-synthesis and intrapituitary TSH were not altered by deafferentation or TRH. In summary, 1) anterior hypothalamic deafferentation decreases basal TSH protein and carbohydrate synthesis; 2) such deafferentation increases sensitivity to TRH stimulation of TSH synthesis, most notably apoprotein synthesis; 3) TRH increases relative glycosylation of secreted TSH in both deafferented and sham groups. These data suggest that TRH plays a significant role in regulating basal TSH protein and carbohydrate synthesis, glycosylation of TSH subunits, and subsequent bioactivity.

Pharmacokinetics and bioavailability of the anti-emetic agent bromopride

The pharmacokinetics of bromopride, an anti-emetic agent chemically related to metoclopramide, has been investigated in normal human subjects. After intravenous bolus doses of 10 mg, a one-compartment open model appeared adequate to describe the plasma drug concentration data. The systemic clearance of bromopride was 899 ml min-1 +/- 22 per cent CV, the volume of distribution was 2151 +/- 16 per cent CV, and the elimination half-life was 2.9 h +/- 21 per cent CV. Over a wide drug concentration range of up to 650 ng ml-1, bromopride was only 40 per cent bound to plasma proteins. The systemic availability of orally and intramuscularly administered solution doses of 20 mg of bromopride was 54 per cent and 78 per cent, respectively. Formulation of bromopride as the solid material in capsules delayed absorption but did not affect the extent of drug bioavailability. The pharmacokinetics of bromopride appeared similar to that of metoclopramide. No evidence for non-linear kinetics was found when bromopride was administered orally in the dose range 10-30 mg: after single oral doses of 10, 20, and 30 mg, peak mean plasma drug concentrations were 20 ng ml-1 +/- 32 per cent CV, 38 ng ml-1 +/- 16 per cent CV, and 64 ng ml-1 +/- 23 per cent CV, respectively.

Radiation-induced hemopoietic death in mice as a function of photon energy and dose rate

Radiation-induced hemopoietic death was measured in mice exposed to photons of four different energies: 250-kVp X rays, 60Co gamma rays (1.25 MeV), and 6- and 25-MV photons from a linear accelerator. For each radiation source, the lethal dose which killed 50% of the population in 30 days (LD50/30) associated with the hemopoietic syndrome was determined in groups of mice exposed to graded doses from 600 to 1150 cGy at dose rates of 20, 40, and 80 cGy/min. The calculated LD50/30 values for 25 and 6 MV were significantly different from each other at all exposure rates while no difference was observed between 6 MV and 60Co. Using 60Co gamma rays as the standard, the relative biologic effectiveness was as follows: 250 kVp greater than 25 MV greater than 6 MV = 60Co. The data suggest that there may be a greater damage to tissue within the marrow cavities following exposure to very high megavoltage radiation, a factor which must be considered with the increasing utilization of linear accelerators in the clinic and laboratory.