Pathophysiological evaluation associated with sustained delivery of danazol and dihydrotestosterone in adult male rodents.

The objective of this investigation was to evaluate histologically and pathologically the effect of long-term sustained release of D and DHT on the reproductive system of male rats. A total of 120 Sprague-Dawley male albino rats were distributed equally into three groups. Two CDD, one nonimpregnated and the other impregnated with PLA, were implanted in each rat in groups I and II.

Pulsatile delivery of progesterone and estradiol to mimic the ovulatory surge in adult ewes by means of TCPL implants.

Tricalcium-phosphate-lysine delivery systems (TCPL) have been developed to release pharmaceuticals into the circulation, at a predictable rate, for prolonged periods of time. The objective of this study was to design an implantable TCPL system capable of delivering progesterone (P) for about two weeks and Estradiol (E) in a short burst that mimics the ovulatory surge in adult ewes. TCPL implants were fabricated in four different sizes (1.

Successful antidote of multiple lethal infections using sustained delivery of difluoromethylornithine by means of ceramic drug delivery devices.

The objectives of this study were (1) to cure multiple infections of trypanosomiasis in rats by the sustained release of DFMO from biodegradable tricalcium phosphate (TCP) and aluminum-calcium-phosphorous oxide (ALCAP) delivery systems, and (2) to determine if the side effects associated with oral administration of DFMO can be avoided by using TCP and ALCAP capsules. Sixty-eight SD male albino rats (235-270 g) were divided randomly into five groups. Each rat in group I (n = 16) was implanted subcutaneously (s.

Differentiation of human pituitary adenomas determines the pattern of chromogranin/secretogranin messenger ribonucleic acid expression.

The distribution of chromogranin/secretogranin (Cg/Sg) mRNAs, determined by Northern and in situ hybridization, was analyzed in 14 cultured pituitary adenomas characterized by immunohistochemistry and hormone secretion in a defined medium in vitro. There were 5 functional GH adenomas, 1 silent GH adenoma, 7 null cell adenomas, and 1 oncocytoma. The null cell adenomas, oncocytoma, and silent GH adenomas were also analyzed by electron microscopy.

Mechanisms that cause protein and amino acid catabolism in uremia.

Anorexia and/or a protein- and calorie-restricted diet can cause protein wasting by limiting the intake of essential amino acids (EAA) and, hence, protein synthesis. By this mechanism plus the effects of inadequate calories, restricted diets could contribute to the loss of lean body mass of uremic patients. Uremia also impairs the normal metabolic responses that must be activated to preserve body protein, thereby augmenting the adverse effects of anorexia.

Sustained release of progesterone and estradiol on adult female rats by ceramic delivery devices.

The present study was undertaken with the purpose of investigating the effectiveness of CDS implants to deliver progesterone (P) and estradiol (E) in a sustained levels for long duration using adult female rats as a model. A total of 128 CDS implants, each having a final fired density of 1.88 +/- S.

Affinity binding assay of glycohemoglobin by two-dimensional centrifugation referenced to hemoglobin A1c.

We describe an automated assay of glycohemoglobin performed with the Abbott Vision analyzer. The assay is based on batch affinity-extraction with 3-aminophenylboronic acid-derivatized agarose beads. Reagents are packaged in a disposable test pack.

Influence of ammonia and pH on protein and amino acid metabolism in LLC-PK1 cells.

Metabolic acidosis inhibits protein synthesis (PS) and stimulates protein degradation (PD) in muscle and cultured myocytes but causes hypertrophy of the proximal tubule. The reason for this tissue-specific difference in response to acidosis is unknown, but it might be related to stimulation of renal ammonia production since ammonia reportedly increases PS and inhibits PD in cultured kidney cells. We examined how ammonia and pH could interact to change protein turnover in confluent LLC-PK1 cells.

Chronic metabolic acidosis accelerates whole body proteolysis and oxidation in awake rats.

Previous work has documented an acceleration of proteolysis and branched-chain amino acid oxidation when muscles from rats with chronic metabolic acidosis were incubated in vitro. The present study examines the impact of chronic metabolic acidosis on whole body amino acid turnover and oxidation in chronically catheterized awake male Sprague-Dawley rats using stochastic modeling and a primed continuous infusion of L-[1-14C] leucine. Whole body protein turnover was accelerated by acidosis as reflected in a 70% increase in proteolysis and a 55% increase in protein synthesis.

Cloning of Drosophila transcription factor Adf-1 reveals homology to Myb oncoproteins.

The Drosophila sequence-specific DNA binding protein, Adf-1, is capable of activating transcription of the alcohol dehydrogenase gene, Adh, and is implicated in the transcriptional control of other developmentally regulated genes. We have cloned the cDNA encoding Adf-1 by generating specific DNA probes deduced from partial amino acid sequence of the protein. Several cDNA clones encoding an extended open reading frame were isolated from a phage lambda library.

Characterization of ceramic drug delivery devices: the effect of various temperature of incubation on the delivery of biologicals.

The objectives of this study are: (i) to determine the effect of temperature on the release rate of steroids and proteins from ceramic drug delivery devices (CDDD), and (ii) to examine the effect of polylactic acid (PLA) impregnation of tricalcium phosphate (TCP), and alumino-calcium-phosphorous oxide (ALCAP) ceramic capsules on the release of small and large molecular weight compounds, and (iii) to investigate the interaction of molecular weight and various incubation temperatures (25, 37 and 50 degrees C) on the rate of delivery from CDDD. The CDDD were prepared using standard laboratory protocols. Eight of 16 ALCAP and TCP ceramic capsules were impregnated with PLA and the remainder fabricated without PLA.

Effect of glucocorticoids and extracellular pH on protein metabolism in cultured cells.

Chronic renal failure (CRF) is complicated by metabolic acidosis and muscle wasting. Protein degradation (PD) in skeletal muscle is accelerated in rats with CRF and correction of uremic acidosis returns PD to normal. Experimentally induced acidosis in normal rats accelerates PD and requires an intact adrenal axis.

Metabolic acidosis accelerates whole body protein degradation and leucine oxidation by a glucocorticoid-dependent mechanism.

Previous work documented an acceleration of proteolysis and branched-chain amino acid oxidation when muscles from rats with chronic metabolic acidosis were incubated in vitro. The present study examines the impact of chronic metabolic acidosis on whole body amino acid turnover and oxidation in chronically catheterized, awake, male Sprague-Dawley rats using stochastic modeling and a primed continuous infusion of L[1-14C] leucine. Whole body protein turnover was accelerated by acidosis as reflected in a 70% increase in proteolysis and a 55% increase in protein synthesis.

Controlled release of hydrophilic compounds by resorbable and biodegradable ceramic drug delivery devices.

Hydroxyapatite (HA), aluminum-calcium-phosphorous oxide (ALCAP), bone meal (BM), and tricalcium phosphate (TCP) ceramic implants are biodegradable and nontoxic to the host. The purpose of this study was to investigate the capability of these ceramics to deliver the catecholamine, epinephrine (EPI) in a sustained and controlled manner. The ceramic powder (less than 38 um particle size) was prepared in our laboratory using standard procedures.

A chimeric D2 dopamine/m1 muscarinic receptor with D2 binding specificity mobilizes intracellular calcium in response to dopamine.

Using PCR methodology, a chimeric receptor cDNA was constructed in which the entire third cytoplasmic loop of the human D2 dopamine receptor was replaced by the analogous portion of the human m1 muscarinic receptor. When expressed in CHO cells, the chimeric D2/m1 receptor bound dopaminergic ligands with affinities similar to the native D2(414) receptor. Intracellular calcium levels (measured with Fura-2) were not altered when CHO cells expressing the D2(414) receptor were exposed to dopamine.

Abnormalities in protein synthesis and degradation induced by extracellular pH in BC3H1 myocytes.

Metabolic acidosis impairs protein and amino acid metabolism in rat muscle. To examine how extracellular acidification affects cellular protein turnover, we studied the BC3H1 myocyte. At pH 7.

Tricalcium phosphate amino acid capsules as a drug delivery system for steroid hormones.

Several researchers have reported that there are drawbacks in using the current pharmacotherapeutic procedure for the treatment of endocrine insufficiency. Furthermore, such drugs have to be taken on a lifelong basis. Also, long term exposure to drugs seems to be necessary in the treatment of the most common endocrine disorders.

The effect of various testosterone concentrations released from ceramic delivery systems on the circulating hormone levels of adult castrated rams.

Ceramic delivery systems (CDS) have been found to be useful carriers for chemical and biological materials allowing a constant release of these materials over prolonged periods of time. We reasoned that testosterone (TE) filled CDS could be utilized in the long-term treatment of androgen deficient patients. The specific objective of this study was to investigate the ability of CDS to deliver TE at a sustained level for 90 days using castrated adult rams as a model.

In vivo delivery of estradiol from ceramic drug delivery devices.

Ceramic drug delivery systems (CDS) are capable of delivering a wide variety of chemicals and/or biologicals directly into the systemic circulation in a continuous manner over long intervals with minimum risk to the recipient. The objectives of the present study were: (i) to determine the capability of tricalcium phosphate (TCP) capsules to deliver estradiol (E) in a sustained manner into the circulation of intact adult male rats, and (ii) to investigate the physiological responses associated with the presence of constant levels of estradiol in adult male rats. Microcrystals, particle size of less than 38 um, of TCP powder were prepared using standard procedures.

Effects of acute and chronic uremia on active cation transport in rat myocardium.

As abnormalities of active cation transport could contribute to the genesis of uremic cardiomyopathy, we investigated myocardial sodium pump function in rats with acute renal failure (ARF) and with a model of experimental chronic renal failure (CRF) that has metabolic similarities to advanced chronic uremia in humans. CRF rats were hypertensive and had left ventricular hypertrophy (33% higher heart:body weight ratio; P less than 0.01) at four weeks compared to pair-fed sham-operated rats.

Long-term delivery of testosterone by ALCAP ceramic implants in rats.

The capability of ALCAP ceramic drug-delivery implantable devices to release testosterone for 12 months was investigated. A total of 120 Sprague-Dawley male albino rats were distributed equally into three groups. Two ALCAP capsules, one nonimpregnated and the other impregnated with polylactic acid (PLA) were implanted into each rat in Groups I and II.

Gonadotropin-releasing hormone regulates gonadotropin beta-subunit and chromogranin-B messenger ribonucleic acids in cultured chromogranin-A-positive pituitary adenomas.

Chromogranin-A-positive pituitary adenomas include glycoprotein hormone-producing adenomas, null cell adenomas, and a few other pituitary adenomas. We studied the effects of GnRH, CRF, dexamethasone, and phorbol 12-myristate 13-acetate on FSH and LH secretion and on FSH beta and chromogranin-A and -B mRNA expression in 10 chromogranin-A-positive adenomas in vitro to analyze the regulation of FSH and chromogranin-A and -B expression in these neoplasms. Most adenomas responded to GnRH stimulation during 7 days in culture with a 2- to 10-fold increase in FSH and LH secretion and a 2- to 7-fold increase in FSH beta mRNA compared to control values.

Plasma substance-P in neuroendocrine tumors and idiopathic flushing: the value of pentagastrin stimulation tests and the effects of somatostatin analog.

We examined the role of the potent vasoactive kinin substance-P (SP) in flushing derived from various causes. SP was measured in plasma after acetone/ether extraction using an antiserum directed at the carboxy-terminal 5-11 amino acid region of undecapeptide SP. The antiserum had less than 1% cross-reaction with the other neurokinins, neurokinin-A and neuropeptide-K, that derive from the beta-preprotachykinin gene and share carboxy-terminal residues.

Phenotypic characterization, karyotype analysis and in vitro tamoxifen sensitivity of new ER-negative vulvar carcinoma cell lines, UM-SCV-1A and UM-SCV-1B.

Two cell lines (University of Michigan squamous carcinoma of the vulva UM-SCV-1A and UM-SCV-1B) were established from the primary tumor and a malignant pleural effusion of a 62-year-old woman. Both tumor specimens grew vigorously in vitro and could be passaged after only 14 and 10 days in culture, respectively. Both cell lines undergo 3 population doublings in 4 days, reaching saturation densities of 5 x 10(5) cells/cm2, and have been carried through more than 30 in vitro passages.