Biomedical subjects

C M Thomas

Publications and source records attributed to C M Thomas.

297 records · Page 17Linked to original sources

PubMedDate not supplied

Effect of chronic aromatase inhibition by delta 1-testolactone on pituitary-gonadal function in oligozoospermic men.

Aromatase inhibition by delta 1-testolactone (Teslac, 500 mg twice daily) for 6 months in 9 patients with idiopathic oligozoospermia lowered the levels of serum estradiol (E2) and thereby sex hormone binding globulin (SHBG) (rS = +0.40, p less than 0.025) to values -35 and -25%, respectively, below the pretreatment values (P less than 0.001 and less than 0.005). The E2 decrease was accompanied by a temporary increase (+50%) in the levels of follicle stimulating hormone (FSH), not of luteinizing hormone (LH), and of 17 alpha-hydroxyprogesterone (17 alpha-OHP), but less of testosterone (T) (+30%), which led to a transient rise in the 17 alpha-OHP/T ratio. The T/E2 ratio and "free T" index (T/SHBG) almost doubled until the end of the treatment period. During delta 1-testolactone treatment the mean sperm density gradually rose from 8.1 +/- 1.3 (SEM) before to 21.3 +/- 6.7 X 10(6)/ml after 6 months (P less than 0.01), whereas the total sperm count almost threefold increased (P less than 0.05). Sperm concentrations exceeding 20 X 10(6)/ml were achieved in 4 of the 9 patients. Two of these patients' wives became pregnant. Although the data point to a pivotal role of estrogens in the pathogenesis of the spermatogenic lesion in some patients with idiopathic oligozoospermia, the lack of a beneficial effect of estrogen lowering in others points to a multicausal nature of the disease entity.

Adult↗

PubMedDate not supplied

Testicular steroid response to continuous and pulsatile intravenous luteinizing hormone-releasing hormone administration in normal men.

In 18 healthy normal men Leydig cell response was examined following intravenous luteinizing hormone-releasing hormone (LH-RH) administration under standardized conditions. The same total amount of LH-RH was administered for 3 hours both in a continuous (1 microgram/min; C (1,1)) and in a pulsatile fashion, by giving a 20 micrograms dose at 20 minutes intervals, P (20, 20), and a 60 micrograms dose at 60 minutes intervals, P (60, 60). Following the different modes of LH-RH administration which all caused 3-4 fold elevations of the mean endogenous luteinizing hormone (LH) concentrations and 1.7-2 fold elevations of the mean follicle-stimulating hormone (FSH) serum levels, an overt increase of the mean testosterone (T) levels was noticed up to 1.5 X the baseline value. No difference was observed in the total amount of T release among the investigated groups. The patterns of the T response, however, clearly differed from one another with a rapid increase, during the C (1, 1) and the P (20, 20) LH-RH administration, and a delayed but persistent T increase in the P (60, 60) experiment. The mean 17-hydroxyprogesterone (17-OHP) concentrations demonstrated a similar course to T in the P (60,60) experiment, while significant increases of the oestradiol (E 2) levels were never observed in all three experiments. In view of the comparable LH and FSH increments in response to LH-RH administration in either experiment the differences in T responses may be explained by assuming a direct effect of LH-RH on Leydig cell steroidogenesis in the men.

17-alpha-Hydroxyprogesterone↗

PubMedDate not supplied

Elevated serum endothelin-1 levels in patients with colorectal cancer; relevance for prognosis.

BACKGROUND: It has been demonstrated that the Doppler Perfusion Index (DPI) is increased in patients who are at risk of developing liver metastases from colorectal cancer. It has been postulated that a circulating hormonal factor is involved in the relative vasoconstriction throughout the splanchnic bed. Endothelin-1 (ET-1), a potent vasoconstrictor which has been associated with tumor growth and is produced by colorectal tumors, may play an important role in this phenomenon. In this paper the prognostic value of serum ET-1 in colorectal cancer is discussed. METHODS: Preoperative serum levels of ET-1 were assessed in three groups of patients: group A underwent resection of the colorectal tumor and remained free of recurrence (n=20); group B developed metachronous liver metastases at least six months after colorectal resection (n=14); and group C presented with colorectal cancer and synchronous liver metastases (n=22). RESULTS: The mean (SD) serum ET-1 levels in groups A, B and C were 1.59 (0.41) pmol/L, 1.70 (0.32) pmol/L and 1.85 (0.47) pmol/L, respectively. These values were significantly different from those of healthy controls (1.22 (0.31), p<0.05). Kaplan-Meier analyses revealed no prognostic value of preoperative serum ET-1 levels. CONCLUSIONS: These preliminary results demonstrate that serum ET-1 levels are raised in patients with colorectal cancer. Serum ET-1 levels do not seem to be of prognostic value for survival.

Adult↗

PubMedDate not supplied

Serum tumor markers: past, state of the art, and future.

Serum determinations of tumor markers are indispensable in the diagnosis and management of cancer, and therefore play an important role in clinical practice. After a short historical survey, we systematically review a number of contemporary aspects of serum tumor markers related to various organ systems, and briefly indicate possible future developments.

Biomarkers, Tumor↗

PubMedDate not supplied

[Nah-plasmids of IncP-9 group from natural strains of Pseudomonas].

Use of polymerase chain reaction helped to establish that the most frequent among naphthalene utilizing bacteria, isolated on the territory of Belarus, are Nah-plasmids of IncP-9 incompatibility group and those with indefinite systematic belonging. With the help of classical test of incompatibility, restriction and sequence analyses three new subgroups within the IncP-9 group were discovered (zeta, eta and IncP-9-like replicons). Conducting of restriction analysis for amplification products of nahG and nahAc genes allowed us to reveal, in addition to known sequences of stated determinants, two new types of nahG gene. Restriction analysis performed on amplification products of 16S RNA genes (ARDRA method) showed that native hosts of Nah-plasmids of IncP-9 group are not only fluorescent bacteria from genus Pseudomonas (P. fluorescens, P. putida, P. aeruginosa, P. species), but also non-fluorescent bacteria with indefinite specific belonging.

Genes, Bacterial↗

PubMedDate not supplied

Follicular fluid hormone concentrations after ovarian stimulation using gonadotropin preparations with different FSH/LH ratios. I. Comparison of an FSH-dominant and a purified FSH preparation.

OBJECTIVE: A small amount of LH is necessary for 17beta-estradiol production in the ovarian follicle. Human menopausal gonadotropin (hMG) contains equal amounts of FSH and LH activity, whereas recombinant FSH is a gonadotropin preparation without LH. The aim of the present randomized study was to investigate whether ovarian stimulation treatment with recombinant FSH or hMG resulted in different steroidal composition of follicular fluid. METHODS: Antral fluid from mature follicles was collected in in vitro fertilization cycles and concentrations of testosterone, androstenedione, estrone, estradiol, progesterone, FSH, and LH were determined. Seven patients (27 samples) were treated with hMG, 6 patients (22 samples) with recombinant FSH. RESULTS: Androgen, estrogen, progesterone, and FSH concentrations in follicular fluid tended to be lower in the group treated with recombinant FSH, but the variation was large and differences were statistically not significant. CONCLUSION: Treatment with a gonadotropin preparation containing no LH resulted in adequate androgen and estrogen levels in antral fluid of the ovarian follicle in women with normal endocrine profiles, even during pituitary suppression by a GnRH agonist. Apparently, the amount of endogenous LH was sufficient for steroid production within the follicle.

Adult↗

PubMedDate not supplied

Follicular fluid hormone concentrations during controlled ovarian hyperstimulation using gonadotropin preparations with different FSH/LH ratios. I. Comparison of an FSH-dominant and a purified FSH preparation.

OBJECTIVE: The aim of the present randomized study was to investigate whether ovarian stimulation treatment with gonadotropin preparations containing different amounts of LH activity resulted in variations of steroidal composition of follicular fluid. A different endocrine milieu within the follicle might influence oocyte quality. METHODS: Antral fluid from mature follicles was collected in in vitro fertilization cycles and concentrations of testosterone, androstenedione, estrone, estradiol, progesterone, FSH, and LH were determined. A comparison was made between treatment with a purified FSH preparation (nine patients, 35 follicular fluid samples) and a FSH-dominant human menopausal gonadotropin (hMG) preparation (nine patients, 34 samples). RESULTS: No differences in any of the hormone levels could be detected between the two groups. CONCLUSION: Treatment with gonadotropin preparations containing different FSH/LH ratios did not result in different androgen, estrogen and progesterone levels in follicular fluid.

Adult↗

PubMedDate not supplied

Follicular fluid hormone concentrations after ovarian stimulation using gonadotropin preparations with different FSH/LH ratios. II. Comparison of hMG and recombinant FSH.

OBJECTIVE: A small amount of LH is necessary for 17 beta-estradiol production in the ovarian follicle. Human menopausal gonadotropin (hMG) contains equal amounts of FSH and LH activity, whereas recombinant FSH is a gonadotropin preparation without LH. The aim of the present randomized study was to investigate whether ovarian stimulation treatment with recombinant FSH or hMG resulted in different steroidal composition of follicular fluid. METHODS: Antral fluid from mature follicles was collected in in vitro fertilization cycles and concentrations of testosterone, androstenedione, estrone, estradiol, progesterone, FSH, and LH were determined. Seven patients (27 samples) were treated with hMG, 6 patients (22 samples) with recombinant FSH. RESULTS: Androgen, estrogen, progesterone, and FSH concentrations in follicular fluid tended to be lower in the group treated with recombinant FSH, but the variation was large and differences were statistically not significant. CONCLUSION: Treatment with a gonadotropin preparation containing no LH resulted in adequate androgen and estrogen levels in antral fluid of the ovarian follicle in women with normal endocrine profiles, even during pituitary suppression by a GnRH agonist. Apparently, the amount of endogenous LH was sufficient for steroid production within the follicle.

Adult↗

PubMedDate not supplied

Serum CA 125 measurements to identify patients with endometrial cancer who require lymphadenectomy.

BACKGROUND: Most studies evaluating the role of serum CA 125 measurements in endometrial cancer report a positive correlation with prognostic factors. The present study investigates the role of serum CA 125 measurements as a preoperative aid in the decision whether lymphadenectomy or sampling should be part of the surgical procedure. PATIENTS AND METHODS: We retrospectively studied clinical data of 98 patients with endometrial cancer (FIGO stage I to III), who had serum samples available for analysis of IMx CA 125. Clinical information was included in the analysis in the order in which it became available to the clinician. Patients were grouped retrospectively on the basis of histopathologically determined factors. Those with grade 3 tumors, and/or myometrial invasion > or = 1/2, and/or cervical involvement, and/or parametrial or adnexal tissue involvement, and/or blood vessel invasion, were retrospectively assigned to require lymphadenectomy or sampling (N = 60). All other patients were classified as not requiring such a procedure (N = 38). RESULTS: Serum IMx CA 125 concentrations correlated with all factors included in the surgical FIG0 classification. The sensitivity to identify patients who would have required a lymphadenectomy or sampling on the basis of precurretage serum CA 125 measurements ranged between 17% (10/60) with cut-off of 35 U/ml, and 53% (32/60) with a 15 U/ml cut-off. Corresponding specificity to exclude patients for lymphadenectomy or sampling ranged from 95% (36/28) to 76% (29/38), respectively. After curettage, information regarding histological grade became available. Using only this information, 17 out of 60 patients who would have required a lymphadenectomy or sampling could be identified because of their grade 3 tumor. The combination of serum CA 125 and histological grade could identify between 37% (22/60) and 65% (39/60) of the patients who required a lymphadenectomy or sampling cut-offs again ranging from 35 to 15 U/ml. CONCLUSIONS: CA 125 serum levels may provide additional information in the preoperative assessment of endometrial cancer patients. More studies are needed to establish the appropriate cut-off level for serum CA 125 in this respect.

Adult↗