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.