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Biomedical subjects

R E Reid

Publications and source records attributed to R E Reid.

At least 19 recordsLinked to original sources

Enhanced expression of insulin-like growth factor-binding protein-I in the fasted rat: the effects of insulin and growth hormone administration.

The effect of fasting on insulin-like growth factor-binding protein-1 (IGFBP-1) expression was examined in the rat. Food deprivation for a period of 24 h resulted in a 9.5 +/- 2.0-fold increase in hepatic IGFBP-1 mRNA abundance (P less than 0.001). An increase in circulating IGFBP-1 in sera from fasted rats was demonstrated by immunoblotting, and an increased abundance of a 30-kDa IGFBP in sera from fasted rats was apparent when [125I]IGF-I was used in ligand blotting experiments. Refeeding resulted in a prompt decline in hepatic IGFBP-1 mRNA. Administration of insulin (0.5-4 U, ip) to fasted rats resulted in profound hypoglycemia, but either increased or had no significant effect on hepatic IGFBP-1 mRNA abundance. In contrast, administration of human GH (hGH; 100 micrograms, ip) resulted in a prompt decline in hepatic IGFBP-1 mRNA, followed by a late rebound in IGFBP-1 mRNA to levels greater than those in fasted controls. Furthermore, hepatic IGFBP-1 mRNA levels were significantly lower in hGH-treated (100 micrograms every 8 h) food-deprived rats than in saline-treated food-deprived rats (2.25 +/- 1.55- vs. 8.99 +/- 3.80-fold increase; P less than 0.005). Similar changes were observed when serum IGFBP-1 was quantitated by immunoblotting. The effects of GH could not be explained by secondary hyperinsulinism, since no significant increase in insulin levels was observed in GH-treated rats. From these observations we conclude the enhanced expression of IGFBP-1 in the food-deprived rat may be a consequence of GH deficiency rather than insulin deficiency.

Animals

Synthetic fragments of calmodulin calcium-binding site III. A test of the acid pair hypothesis.

The acid pair hypothesis describing the interaction of calcium with the helix-loop-helix conformation of EF hands in calmodulin and related proteins predicts that these calcium-binding sites will have increased affinity for calcium if the anionic amino acid dentates in the loop region which interact directly with the cation are paired on the axial vertices of the resulting octahedral arrangement of chelating residues about the cation. As a test of this hypothesis, synthetic 33 residue analogs of bovine brain calmodulin calcium-binding site III have been prepared by the solid-phase method and analyzed for calcium affinity. The native sequence has a Kd of 735 microM for calcium and contains three anionic ligands which assume the +x, +y, and -z coordinates of the octahedral arrangement about the cation, thus precluding any pairing of the anionic ligands. This dissociation constant is 26 times weaker than that obtained from a synthetic analog of the sequentially homologous calcium-binding site III of rabbit skeletal TnC (Kd = 28 microM) which has four anionic ligands paired on the x and z axes. An analog of calmodulin site III with substitutions in the chelating residues at positions 1, 3, 5, 7, 9, and 12 of the 12-residue loop region to make these positions identical to those of rabbit skeletal troponin C site III decreased the calcium dissociation constant of the calmodulin peptide to 19 microM, similar to the troponin C peptide. Two synthetic analogs of calmodulin site III which contain three anionic ligands with two ligands paired on the x axis and two on the z axis have a Kd for calcium of 524 and 59 microM, respectively. This study provides strong support for and a better definition of the acid pair hypothesis and further demonstrates the usefulness of synthetic calcium-binding fragments in delineating the mechanism of calcium regulation of calmodulin and related proteins.

Amino Acid Sequence

Paravesical granulomas masquerading as bladder neoplasms: late complications of inguinal hernia repair.

Paravesical granuloma formation after inguinal herniorrhaphy is a rare complication due to infected suture material. We present 8 cases of large paravesical granulomas masquerading as bladder tumors. Irritable symptoms predominate the symptom complex and accurate diagnosis can be obtained with multiple, sonographically guided, needle biopsies of the mass. An operation results in complete resolution of the symptoms, while nonoperative management may help to improve but not resolve the symptoms.

Diagnosis, Differential

Unilateral testicular torsion: abnormal histological findings in the contralateral testis--cause or effect?

A histological review of testicular biopsies of the contralateral testis, obtained at the time of surgical intervention for testicular torsion, was performed in 20 post-pubertal men. Contralateral histological abnormalities were found in 12 specimens. The duration of torsion correlated well with the viability of the involved testis but not with the presence of contralateral abnormalities. The high incidence of contralateral histological abnormalities and their nature suggest that they existed prior to the torsion since they would be unlikely to appear at such an early stage. We believe that some patients who suffer testicular torsion probably have congenital anomalies of both testes. These abnormalities involve testicular parenchyma as well as the suspension system.

Adolescent

Mapping antigenic sites on the major outer membrane protein of Chlamydia trachomatis with synthetic peptides.

The antigenicity of the major outer membrane protein (MOMP) of Chlamydia trachomatis was comprehensively evaluated by using overlapping hexapeptide homologs of serovar B MOMP and polyclonal rabbit antisera in a peptide enzyme-linked immunosorbent assay. Of 367 hexapeptides, 152 showed reactivities with at least one antiserum. Seven hexapeptides located within variable domain (VD) IV (residues 288 to 316) were found to be most reactive in terms of their binding titer and frequency, suggesting that VD IV is the immunodominant region within the MOMP as detected by this assay. Peptide-reactive antibodies could also recognize corresponding epitopes on either viable or acetone-permeabilized organisms. The antigenic specificity and immunoaccessibility of epitopes located in VD IV were resolved by absorbing antisera with chlamydial elementary bodies. Six antigenic sites were found in this region and included a B-type-specific site (S1), four subserogroup-specific sites (S2 and S4 to 6), and one species-specific site (S3), each displaying varying degrees of surface exposures on elementary bodies from different C. trachomatis serovars.

Animals

Dexamethasone increases hepatic insulin-like growth factor binding protein-1 (IGFBP-1) mRNA and serum IGFBP-1 concentrations in the rat.

Glucocorticoid excess is associated with growth retardation in both man and experimental animals. We have previously reported that dexamethasone (DXM) inhibits growth hormone induction of insulin-like growth factor-I (IGF-I) mRNA in the hypophysectomized rat and reduces steady-state IGF-I mRNA levels in the intact rat. However, in these experiments, DXM had surprisingly little effect on serum IGF-I concentrations. Here, we have examined the effect of DXM on hepatic insulin-like growth factor binding protein-1 (IGFBP-1) mRNA levels and on serum IGFBP-1 concentrations. After a single ip injection of DXM, 6 micrograms/100 g body wt, IGFBP-1 mRNA increased 2.24 +/- 0.25-fold, P less than 0.05 at 1 h and declined to normal levels in 6-12 h. A dose-dependent increase in increased hepatic IGFBP-1 mRNA abundance was seen in rats killed 1 h after an ip injection of DXM, 0.1 to 60 micrograms/100g body wt. As little as 1 microgram/100g body wt, significantly enhanced hepatic IGFBP-1 mRNA levels; 2.02- +/- 0.38-fold, P less than 0.05. This effect appeared to be post-transcriptional, since IGFBP-1 transcription in hepatic nuclei from rats treated with DXM was not significantly different from untreated rats. When DXM, 1 microgram/rat, was administered daily for 6 days a significant increase in IGFBP-1 mRNA was detected; 2.02 +/- 0.39-fold, P less than 0.05. A more marked increase was seen with 6 and 60 micrograms/rat of DXM; 4.47 +/- 1.08- and 10.61 +/- 0.31-fold, respectively. Serum was analyzed by sodium dodecyl sulfate-plyacrylamide gel electrophoresis and immunoblotting using antisera raised against a synthetic peptide derived from the predicted sequence of rat IGFBP-1. The antisera recognized a doublet of approximately 30 kDa. A dose-dependent increase in the abundance of these BPs were seen in the serum from rats treated chronically with DXM. The observations reported here clearly demonstrate that DXM increases hepatic IGFBP-1 mRNA and serum IGFBP-1 concentrations. If IGFBP-1 functions to decrease the bioavailability of IGF-1 in vivo the enhanced expression of IGFBP-1 may be an additional mechanism whereby glucocorticoid excess results in growth retardation.

Animals

Identification of a serum-inducible messenger RNA (5B10) as the mouse homologue of calcyclin: tissue distribution and expression in metastatic, ras-transformed NIH 3T3 cells.

A mouse mRNA, provisionally designated 5B10, has been cloned based on its inducibility by serum in quiescent murine fibroblasts. Here we report the full-length complementary DNA sequence and a partial characterization. There are about five copies of the gene in the mouse genome. Sequence analysis of the 5B10 coding region reveals 94 and 97% amino acid identity to human and rat calcyclin, respectively. Although the coding region has been highly conserved during evolution of the rodent and human genomes, the untranslated flanking sequences differ significantly. A protein of Mr about 8000 was produced by in vitro translation of the mRNA transcribed in vitro from 5B10 complementary DNA in a riboprobe vector. An antiserum raised against a portion of the predicted human calcyclin protein cross-reacted with this mouse protein. 5B10 mRNA was found in greatest amount in organs containing proliferating cells, e.g., epidermis, skin, stomach, uterus of pregnant mouse, placenta, and decidua. Brain, liver, mature thymus, and skeletal muscle had little or no detectable 5B10 mRNA. 5B10 mRNA levels were higher in cells treated with 7,12-dimethylbenzanthracene and 12-O-tetradecanoylphorbol-13-acetate than in their normal counterparts, suggesting a role in tumorigenesis. In addition, high 5B10 mRNA levels were associated with metastatic ability in a series of ras-transformed cells, in proportion to levels of ras p21 expressed by the cells, implicating 5B10 even more deeply in carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene

Crystallization of a synthetic analog of calcium-binding site III of rabbit skeletal troponin C.

Single crystals of the calcium-binding peptide AcA98STnC (90-123)amide, which is a synthetic fragment analog of rabbit skeletal troponin C calcium-binding site III, have been grown in the tetragonal crystal system. Crystals were developed to a maximum size of 0.60 x 0.60 x 0.75-mm by the technique of washing and reseeding. The space group is I41 with a = 40.21(1) A, c = 34.07(1) A; there is 1 polypeptide fragment/crystallographic asymmetric unit, and the solvent content is estimated to be 29%. The crystals diffract to at least 1.8-A d spacings and are stable in the x-ray beam for 1 week.

Animals

Detection of testicular endocrine abnormalities and their correlation with serum antisperm antibodies in men following vasectomy.

We measured the serum gonadotropin response to gonadotropin-releasing hormone in 25 men who underwent vasectomy 2 to 64 months before the study. Ten age-matched fertile men were used as controls. Baseline serum follicle-stimulating hormone, luteinizing hormone and testosterone levels were not significantly different between vasectomized men and controls. However, mean serum follicle-stimulating and luteinizing hormone responses to an intravenous bolus injection of 100 mcg. gonadotropin-releasing hormone were significantly greater in the vasectomy group (p equals 0.008 and 0.003, respectively). There was no correlation between these responses and the interval after vasectomy. Serum antisperm antibodies were present in 13 vasectomized men (52 per cent) using enzyme-linked immunosorbent assay and microagglutination techniques. A significant correlation (p equals 0.003) was found between the presence of serum antisperm antibodies and a normal follicle-stimulating hormone response to gonadotropin-releasing hormone stimulation. Of 13 patients with demonstrable antisperm antibody titers 9 (69 per cent) had normal follicle-stimulating hormone responses, compared to only 1 of 12 (8 per cent) without identifiable antisperm antibody titers. Our data suggest that certain men following vasectomy have abnormalities in seminiferous tubule and Leydig cell functions of the testes. These abnormalities are unrelated to the interval after vasectomy and are not identifiable with routine static hormonal measurements. In addition, serum antisperm antibodies are most likely to be present in men who demonstrate normal seminiferous tubular activity after vasectomy.

Adult

Correlation of the antiproliferative action of diphenylmethane-derivative antiestrogen binding site ligands with antagonism of histamine binding but not of protein kinase C-mediated phosphorylation.

The nonestrogen receptor-mediated antiproliferative action of antiestrogen binding site (AEBS) ligands, including triphenylethylene antiestrogens and phenothiazines, has been linked to their ability to inhibit protein kinase C (PKC). Recent studies indicate that some diphenylmethane derivatives inhibit growth, are potent AEBS ligands, and antagonize histamine binding at an AEBS-related histamine site different from H1 and H2. Three novel diphenylmethane derivatives, N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine.HCI (DPPE), 4-decanoyl-DPPE (dec-DPPE), and 4-benzylphenyl decanoate (BPD) were studied in an attempt to determine whether PKC or histamine interactions best correlate with their antiproliferative effects. Platelet aggregation and the phosphorylation of a platelet Mr 47,000 protein (p47) induced by phorbol-12-myristate-13-acetate (PMA) represent two processes mediated by PKC. DPPE inhibits PMA-induced aggregation [50% inhibitory concentration (IC50) = 31.2 +/- 2.4 (SEM) x 10(-6) M] but does not significantly inhibit either PMA-induced phosphorylation of Mr 47,000 protein (IC50 greater than 500 x 10(-6) M), or binding of [3H]phorbol dibutyrate to platelets. dec-DPPE is a more potent inhibitor of PMA-induced platelet aggregation (IC50 = 18.8 +/- 0.7 x 10(-6) M), a weak inhibitor of Mr 47,000 phosphorylation (IC50 = 80-200 x 10(-6) M), but is without effect on [3H]phorbol dibutyrate binding. BPD, which lacks the alkylaminoethoxy side chain necessary for binding to the AEBS/DPPE site, is devoid of anti-PMA effects. These results are compared to the inhibition of [3H]histamine binding in rat cortex membranes (Ki value for DPPE = 0.83 +/- 0.62 x 10(-6) M; Ki value for dec-DPPE = 6.6 +/- 3.5 x 10(-6) M; BPD is inactive) and growth inhibition of MCF-7 cells (IC50 value for DPPE = 4.5 x 10(-6) M; IC50 value for dec-DPPE = 1.5 x 10(-5) M; BPD is ineffective at all concentrations tested). Thus, while dec-DPPE is a more potent inhibitor of PKC-mediated phosphorylation, DPPE is a more potent inhibitor of histamine binding and is correspondingly more antiproliferative than dec-DPPE. The results support a relationship between antagonism of histamine binding and growth inhibition but argue against an association between the antiproliferative effects of DPPE and dec-DPPE and inhibition of PKC. The findings for DPPE suggest that platelet response to PMA, antagonized by diphenylmethane-type AEBS-ligands, may be mediated, at least in part, by mechanisms other than activation of protein kinase C-dependent phosphorylation.

Animals

Urachal remnants in adults.

Urachal disorders are uncommon and present with varied appearances. Three cases of urachal disease, one congenital and two acquired, are reported. Each case is representative of the symptoms and findings of its respective category. A review of the literature is presented. A basic understanding of urachal development is necessary to suspect a diagnosis of urachal disease.

Adult

Gonadal dysfunction after testicular torsion: luteinizing hormone and follicle-stimulating hormone response to gonadotropin releasing hormone.

We studied 14 postpubertal patients at an average of 33 months after treatment for testicular torsion. Of these patients 11 had been treated by detorsion and 3 by orchiectomy. Five normal male volunteers of the approximate age of the study group served as controls. The patients treated by detorsion were subdivided into 3 groups based on the degree of atrophy of the detorsed testicle: group 1--no testicular atrophy (5), group 2--25 per cent testicular atrophy (2) and group 3--greater than 90 per cent testicular atrophy (4). Mean duration of torsion was greatest in the orchiectomy group (161 hours) compared to 6, 16 and 29 hours for groups 1, 2 and 3, respectively. The serum luteinizing hormone and follicle-stimulating hormone response to an intravenous bolus of 100 mcg. synthetic gonadotropin releasing hormone was measured in all patients. All groups had a greater mean follicle-stimulating hormone response to gonadotropin releasing hormone stimulation than controls (p less than 0.05). Patients who underwent orchiectomy had the greatest follicle-stimulating hormone response to gonadotropin releasing hormone stimulation. Mean luteinizing hormone response to gonadotropin releasing hormone stimulation was normal in patients without atrophy (group 1) but it was greater than controls in patients who had atrophy (groups 2 and 3) or who underwent orchiectomy (p less than 0.05). Several conclusions could be made from our study. All patient groups treated for torsion had evidence of testicular dysfunction. Patients who underwent orchiectomy displayed more testicular dysfunction than patients who had atrophy after detorsion. Testicular dysfunction after torsion is more likely to involve spermatogenic before Leydig cell function.

Adolescent

Continence mechanisms following transphincteric urethroplasty.

Urinary continence mechanisms were studied in 6 patients, 5 of whom had undergone end-to-end urethroplasty for membranous urethral strictures. All patients were able to interrupt the urinary stream on command by contracting the distal intrinsic sphincteric mechanism, despite an absent extrinsic sphincter. In 2 patients with prostatectomy and transphincteric urethroplasty, the intrinsic sphincteric mechanism was the sole remaining sphincter. These observations suggest that the intrinsic sphincteric mechanism is intramurally located, is also under somatic innervation and alone is capable of performing all of the sphincteric function required in the male.

Humans

A synthetic 33-residue analogue of bovine brain calmodulin calcium binding site III: synthesis, purification, and calcium binding.

The sequential solid-phase synthesis of a peptide analogue of bovine brain calmodulin calcium binding site III covering residues 81-113 of the natural sequence is described. Methionine-109 is replaced by a leucine residue to avoid complications in the synthesis and purification. In an attempt to relate the structure of the calcium binding sites in the naturally occurring calcium binding protein to the calcium affinity of these sites, the synthetic analogue is examined for calcium binding by circular dichroism spectroscopy. The calcium binding characteristics are compared to those of a synthetic analogue of the homologous calcium binding site III in rabbit skeletal troponin C. The Kd of the calmodulin site III fragment for Ca2+ is determined as 878 microM whereas the Kd of the troponin C fragment is 30 times smaller at 28 microM. Structural changes induced in the peptides by Ca2+ and trifluoroethanol are similar. This study supports our contention that the single synthetic calcium binding site is a reasonable model for the study of the structure-activity relationships of the calcium binding sites in calcium-regulated proteins such as calmodulin and troponin C.

Amino Acid Sequence

Unstable bladder: urodynamic diagnosis and observations in evaluating urinary incontinence in the female.

Unstable bladder in the female has been the subject of controversy with regard to its etiology, identification, and treatment. One hundred thirty consecutive female patients referred with incontinence were evaluated as to their symptoms and urodynamic findings. A stress cystometrogram, systematically done, was introduced and observations were made regarding certain findings on the urodynamic examination. These criteria were used subsequently for making a diagnosis of unstable bladder. Forty per cent of these patients were found to have an unstable bladder. History of frequency and urgency correlated best with a diagnosis in 70 to 80 per cent of our cases, and the new stress cystometrogram proved to be the most sensitive urodynamic test (78%) for detecting this condition. A systematic approach such as we describe is advocated as a first step toward gaining a better understanding of this puzzling entity.

Female

Total sequential solid phase synthesis of rabbit skeletal troponin C calcium binding site III.

The total sequential solid phase synthesis of AcA98STnC(90-123)amide is described. The yield is comparable to that obtained previously using fragment condensation on the solid support. HPLC purification results in a product which displays greater calcium induced conformational changes than the peptide prepared by the fragment condensation method. However, the former has a dissociation constant for calcium (28 microM) seven times higher than the latter (4 microM).

Binding Sites

Role of urodynamics in management of urethral diverticulum in females.

This report deals with 10 female patients with urethral diverticula, 8 of whom were also found to have findings of stress incontinence. This association was proved by urodynamic studies. Three patients were seen with incontinence postdiverticulectomy. Seven patients were evaluated prior to diverticulectomy, and of these 5 had anatomic changes of stress urinary incontinence. Those patients in whom the preoperative evaluation considered them to be at risk for development of stress incontinence postdiverticulectomy were treated with a prophylactic urethropexy. Patients so treated were continent and voided well and were probably spared having a postoperative problem with incontinence. The role of urodynamic techniques in the detection of any association between the diverticulum and a possible risk of postdiverticulectomy incontinence, and how to recognize the problem and its correction before it becomes clinically manifest are the stated purposes of this report.

Diverticulum