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Biomedical subjects

D Thurston

Publications and source records attributed to D Thurston.

13 recordsLinked to original sources
PubMed2000

The gain-of-function G389R variant of the beta1-adrenoceptor does not influence blood pressure or heart rate response to beta-blockade in hypertensive subjects.

Mutation scanning of the beta1-adrenoceptor gene has identified a polymorphism, G389R, that markedly affects G-protein coupling of the receptor and resulting cAMP production. We have investigated the effect of this functionally active polymorphism on clinical response to beta-adrenoceptor blockade. Two cohorts of untreated hypertensive patients randomly assigned to a beta1-selective beta-blocker at the start of antihypertensive therapy were studied retrospectively to see if the G389R polymorphism influenced the response in terms of blood pressure and heart rate. The blood pressure and heart rate responses to treatment were assessed 4 weeks later and compared with the G389R genotype, ascertained by PCR/restriction fragment length polymorphism. The falls in blood pressure and heart rate for the first group (n = 92) by genotype were: GG, 20.1 +/- 3.5/13.9 +/- 2.7 mmHg (systolic/diastolic blood pressure), 18.4 +/- 2.2 beats/min; GR, 20.0 +/- 2.2/15.0 +/- 1.3 mmHg, 16.5 +/- 1.5 beats/min; RR, 20.8 +/- 2.3/13.4 +/- 1.1 mmHg, 16.0 +/- 1.4 beats/min. For the second group (n = 55) the corresponding falls were: GG, 17.0 +/- 4.3/11.2 +/- 3.4 mmHg, 12.0 +/- 3.5 beats/min; GR, 16.6 +/- 1.8/14.4 +/- 1.1 mmHg, 13.1 +/- 2.1 beats/min; RR, 18.0 +/- 1.6/13.0 +/- 1.4 mmHg, 14.4 +/- 1.4 beats/min. The G389R genotype also failed to have a significant effect on pretreatment blood pressure or heart rate in either group. These data suggest that, despite clear functional differences between the G389R receptor variants expressed in vitro, the polymorphism does not affect the haemodynamic response of hypertensive subjects to chronic beta1-adrenoceptor blockade.

Adrenergic beta-Antagonists↗
PubMed1998

Elevated maternal serum relaxin concentrations throughout pregnancy in singleton gestations after superovulation.

OBJECTIVE: To test the hypothesis that superovulation results in elevated maternal circulating relaxin concentrations throughout the second and third trimesters of pregnancy, independent of the pattern of hCG secretion. METHODS: Two groups of women with singleton gestations were studied: a group of nine women who achieved pregnancy after stimulation with human menopausal gonadotropin and a group of six women who achieved pregnancy without prior stimulation. Peripheral blood samples were drawn approximately every 5 weeks throughout the second and third trimesters. Serum relaxin concentrations were measured using a human relaxin-specific enzyme-linked immunosorbent assay; hCG was measured by an immunofluorometric assay. RESULTS: The stimulated group had significantly higher relaxin levels throughout pregnancy (P=.007, multivariate analysis of variance) than did nonstimulated controls. The mean relaxin level in stimulated patients was 1.78 ng/mL (95% confidence interval [CI] 1.5, 2.17) and in nonstimulated subjects the level was 0.73 ng/mL (95% CI 0.59, 1.25). Spline fits demonstrated that stimulated patients had higher relaxin levels throughout the second and third trimesters. There was no significant difference in hCG concentrations between the two groups (P=.61). CONCLUSION: In singleton gestations after superovulation, maternal serum relaxin concentrations are significantly higher throughout the second and third trimesters of pregnancy. These differences are independent of the pattern of hCG secretion. It appears that luteal relaxin secretion is controlled by factors in addition to hCG.

Adult↗
PubMed1995

Circulating tumor necrosis factor (TNF)-alpha in normally cycling women and patients with premature ovarian failure and polycystic ovaries.

PROBLEM: The purpose of this study was to investigate the levels of tumor necrosis factor (TNF)-alpha in sera of infertile patients having premature ovarian failure (POF) and polycystic ovaries (PCO), and to compare the levels with those in age-matched normally cycling women. METHOD: Levels of TNF-alpha, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2) were measured in the sera of infertile and normal women by the enzyme linked immunosorbent assay (ELISA), fluorescent immunoassay and radioimmunoassay (RIA), respectively. Multiple groups comparisons were performed using Dunnet's test. Post-hoc analysis was performed using a Tukey-Kramer test. P < 0.05 was considered statistically significant. RESULTS: TNF-alpha levels were significantly (P = 0.003 to < .0001) lower in the sera of patients with POF compared to sera of controls and patients with PCO. CONCLUSIONS: TNF-alpha may have a role in ovarian function. Derangement in follicular development, luteal function and atresia results in a change of circulating TNF-alpha levels.

Adult↗
PubMed1994

Comparison of a DSB-120 DNA interstrand cross-linked adduct with the corresponding bis-tomaymycin adduct: an example of a successful template-directed approach to drug design based upon the monoalkylating compound tomaymycin.

The interstrand cross-linked DSB-120-d(CICG*ATCICG)2 DNA adduct (*indicates covalently modified guanine) was examined by two-dimensional NMR and compared to the bis-tomaymycin adduct on the same oligomer. Tomaymycin and DSB-120 form self-complementary adducts with the d(CICGATCICG)2 duplex sequence in which the covalent linkage sites occur between C11 of either drug and the exocyclic 2-amino group of the single reactive guanine on each strand of d(CICGATCICG)2. In the case of DSB-120, this is evidence for the formation of a guanine--guanine DNA interstrand cross-link. Both drugs show formation of an S stereo-chemistry at the covalent linkage site with an associated 3' orientation. While the majority of DNA in these adducts appears to be B-form, DSB-120 interstrand cross-linking induces atypical properties in the 8I nucleotide, indicated by broadening of the 8IH2 proton resonance, non-C2' endo sugar geometry, and unusually weak internucleotide NOE connectivity to the 7C nucleotide. Tomaymycin does not produce this regional dislocation. For tomaymycin, while there are strong NOE connectivities from protons on the five-membered ring to the 8IH2 proton on the floor of the minor groove, the equivalent internucleotide connectivities in DSB-120 are weaker. This indicates that the tomaymycin tail is close to the floor of the minor groove, while the five-membered ring of DSB-120 is more shallowly immersed, perhaps due to strain from cross-linking with a very short linker unit. Last, the conformational stresses induced on the duplex by DSB-120 appear to make the region of covalent attachment more accessible to solvent than is the case for tomaymycin. The 4GN2Hb resonance appears in 100% D2O on the tomaymycin adduct but is only observed in 90% H2O/10% D2O for the DSB-120 adduct. On the basis of these results, the strategies for template-directed DNA cross-linker design are assessed.

Antibiotics, Antineoplastic↗
PubMed1994

Comparison of magnetic resonance imaging and ultrasound in evaluating liver size in Gaucher patients.

Comparison is made between the reliability of two imaging methods (ultrasound and magnetic resonance imaging) to measure changes in the size of the liver in patients undergoing treatment for Gaucher disease. The reliability of either modality in estimating liver size is comparable, as is the reliability of demonstrating changes in the size of the liver with time. The precision of the two measurements is roughly the same.

Adolescent↗
PubMed1992

2-Chlorodeoxyadenosine treatment of low-grade lymphomas.

PURPOSE: Because of the need to identify effective new agents in the treatment of non-Hodgkin's lymphoma and because of the high activity of the purine analog 2-chlorodeoxyadenosine (2-CdA) against chronic lymphocytic leukemia and hairy cell leukemia, a phase II trial of 2-CdA was initiated in patients with low-grade lymphocytic lymphomas. PATIENTS AND METHODS: Forty patients with low-grade lymphocytic lymphomas including diffuse small lymphocytic, follicular small-cleaved, and follicular mixed histologies were enrolled onto the study. Conventional therapies had failed in all patients, and six patients had lymph node biopsies showing evidence of histologic evolution to a higher-grade lymphoma. A total of 107 courses of 2-CdA were administered. There were 27 males and 13 females. The median age was 59 years (range, 37 to 80 years). Patients had received a median of three prior therapies (range, one to six therapies). RESULTS: An overall response rate of 43% was achieved, with eight patients experiencing complete responses (CRs) and nine patients experiencing partial responses (PRs). The duration of responses ranged from 1 to greater than 33 months without maintenance therapy (median duration of response, 5 months). Histology and prior therapy history did not seem to correlate with responses. Significant toxicity was limited to bone marrow suppression; 18% of patients developed neutropenia, and 30% developed thrombocytopenia. CONCLUSIONS: This phase II trial demonstrates that 2-CdA is an effective antilymphocyte, antineoplastic agent with significant activity as a single agent in patients with recurrent or refractory low-grade lymphocytic lymphoma. Responses were achieved with an acceptable toxicity profile. Further trials of this agent in previously untreated patients and in combination regimens are indicated and will be developed.

2-Chloroadenosine↗
PubMed1992

Gaucher disease. Clinical, laboratory, radiologic, and genetic features of 53 patients.

We have reviewed our experiences with the clinical, laboratory, radiologic, and genetic features of 53 patients with Gaucher disease. Most were evaluated during early adult life, with a mean age of 33 years. Our patients were evaluated in a referral center, and therefore the data need to be interpreted with caution when applied to the general patient population, which includes a greater proportion of very mild cases. Thirty-nine patients were Ashkenazi Jews, 13 were non-Jewish and 1 was half-Jewish. The most common presenting symptom was bleeding related to splenomegaly and thrombocytopenia. The chronic symptoms, evaluated an average of 20 years after the diagnosis had been established, were mainly skeletal. Splenectomy had been performed in 43% of our patients and there was no evidence that this procedure accelerated the progression of liver and bone involvement. DNA from the patients was examined for 20 different mutations. The association between the 1226G/1226G genotype and a milder clinical course, and between the 1226G/84GG and 1226/1448C genotypes with more severe clinical manifestations, was confirmed. Repeated follow-up examinations in 29 patients revealed that in the majority of the patients, progression of the disease occurs during childhood, adolescence, or early adulthood with a marked tendency for stabilization thereafter. This observation suggests that Gaucher disease in most of the patients is not a relentless progressive disorder but a rather stable disorder during adulthood. The indications for the newly introduced intravenous enzyme replacement therapy as well as of future experimental treatments should be examined in the light of the natural history of the disease.

Adolescent↗
PubMed1991

Enzyme replacement therapy for Gaucher disease.

Four patients with moderately severe type I Gaucher disease were treated with commercially available mannose terminated glucocerebrosidase (Ceredase; Genzyme, Boston, MA) for up to 13 months. The enzyme was administered at the rate of three to four times weekly at one fourth the total recommended dosage, greatly decreasing the cost. Marked regression of hepatomegaly and improvement in liver function tests, peripheral blood counts, and serum angiotensin-converting enzyme levels were documented. The two patients with pulmonary involvement manifested improvement in pulmonary function tests. Skeletal disease remained unchanged.

Adult↗
PubMed1985

Retinal angiomatosis and pancreatic cysts in von Hippel-Lindau disease: use of computed tomography scanning for diagnosis and surveillance.

Reports of the retinal and pancreatic manifestations of von Hippel-Lindau disease have been previously published. We present a case of von Hippel-Lindau disease in which computed tomography scanning was used in a new manner for diagnosis of retinal disease and for diagnosis and surveillance of pancreatic disease. We emphasize the importance of these new findings and recommend the use of yearly CT scanning of the abdomen. This replaces the previous recommendation of exploratory laparotomy in patients with pancreatic lesions. We further advocate that CT surveillance of the offspring of von Hippel-Lindau disease patients begin in the second decade, with the anticipation of curing potentially serious, blinding, or life-threatening lesions.

Adult↗
PubMed1979

Cyclic nucleotides and the regulation of canine gastric acid secretion.

The response of the cyclic nucleotide system (cAMP, cGMP, adenylate cyclase, guanylate cyclase, and specific phosphodiesterases) to two gastric acid secretagogues, histamine and acetylcholine, and two secretory inhibitors, prostaglandin E2 and secretin, was studied in vivo and in vitro in canine gastric fundic mucosa. Histamine and acetylcholine in vivo failed to stimulate cAMP but significantly increased cGMP; in vitro they affected neither adenylate cyclase nor guanylate cyclase. Prostaglandin E2 and secretin, however, increased cAMP in vivo and significantly stimulated adenylate cyclase in vitro. Specific phosphodiesterases were unaffected by these compounds. The changes, while not specifically localized to the acid-producing cells, are consistent with the suggestion that the control of canine gastric acid secretion may be mediated by changes in mucosal cAMP and cGMP.

Acetylcholine↗