Long-term follow-up of patients with surgical intractable acromegaly after linear accelerator radiosurgery

BACKGROUND/PURPOSE

Radiotherapy is a crucial treatment for acromegalic patients with growth hormone (GH)-secreting pituitary tumors. However, its effect takes time. We retrospectively reviewed the long-term outcome of linear accelerator stereotactic radiosurgery (LINAC SRS) for patients with acromegaly from the perspective of biochemical remission and associated factors.

METHODS

Twenty-two patients presenting with residual or recurrent (GH)-secreting functional pituitary tumor between 1994 and 2004 who received LINAC SRS were enrolled and followed up for at least 3 years. Residual or recurrent tumor was defined as persistent elevated GH or insulin-like growth factor-1 (IGF-1) level and image-confirmed tumor after previous surgical treatment. Biochemical remission was defined as fasting GH less than 2.5 ng/mL with normal sex-and-age adjusted IGF-1.

RESULTS

The mean follow-up period was 94.7 months (range 36-161 months). Overall mean biochemical remission time was 53 months (median 30 months). Biochemical control was achieved in 15 patients (68.2%) over the follow up period. One patient experienced recurrence after SRS and underwent another operation. Initial GH at diagnosis and pre-SRS GH correlated with biochemical control (p = 0.005 and p < 0.0001, respectively). Further evaluation demonstrated that biochemical control stabilized after 7.5 years. Overall post-SRS hormone deficit persisted in five patients (22.7%).

CONCLUSION

In comparison to other radiosurgery modalities, LINAC radiosurgery also provides a satisfactory outcome. SRS has maximum effect over the first 2 years and stabilizes after 7.5 years. Moreover, SRS elicits long-term biochemical effects and requires longer follow-up for better biochemical remission.

In vitro thermal stress induces apoptosis and reduces development of porcine parthenotes

The precise physiological causes that result in reduced development of oocytes after heat shock (HS) are not clear. In this study, apoptosis, heat shock protein70 (hsp70), and in vitro development of porcine oocytes were evaluated after HS. Porcine cumulus-oocyte complexes (COCs) were subjected to in vitro maturation for 42 h. The matured oocytes were then heated at 41.5 degrees C for 0 h (control, C0h), 1 h (HS1h), 2 h (HS2h), or 4 h (HS4h). An additional group of oocytes was cultured for 4 h without HS (control, C4h). In Experiment 1, expression of hsp70 was detected by Western-blotting and no difference between controls and HS groups was observed. In Experiment 2, apoptosis of matured oocytes after HS was examined by Annexin V-FITC and TUNEL. No significant TUNEL-positive signals were detected in the heated oocytes compared to the controls, but the intensity of Annexin V-FITC labeling among different groups increased with length of HS and in vitro culture (P<0.05). Oocytes were parthenogenetically activated by an electric pulse plus 6-DMAP (Experiment 3). Mean (+/-S.E.M.) embryonic development in HS2h (cleavage: 42+/-29%; blastocyst: 11+/-10%) and HS4h (cleavage: 36+/-28%; blastocyst: 11+/-8%) were decreased when compared to those in C0h (cleavage: 63+/-12%; blastocyst: 24+/-14%) and C4h (cleavage: 66+/-8%; blastocyst: 21+/-11%). Numbers of blastocysts with TUNEL-positive signals were similar among groups, but the signals increased before the eight-cell stage in HS groups (P<0.05). In conclusion, developmental competence of matured pig oocytes was compromised after heat shock, but it was not closely associated with the expression of oocyte hsp70. However, there may be a link between apoptosis and developmental competence of porcine oocytes.

Influences of Follicular Size on Parthenogenetic Activation and in Vitro Heat Shock on the Cytoskeleton in Cattle Oocytes

The availability of cow ovaries from the slaughterhouse has been very limited in Taiwan. To maximize the use of cow ovaries for research purposes, whole ovary dissection was performed and the developmental competence of the oocytes derived from different sizes of follicles was assessed by the rates of in vitro maturation (IVM) and parthenogenetic activation of the oocytes in Experiment 1 (Exp 1). Cumulus-oocyte complexes (COCs) derived from small (1-2 mm) and large (3-8 mm) follicles were subjected to standard IVM culture for 24 h. Mature oocytes were selected and then parthenogenetically activated using A23187 (5 microm, 5 min) or thimerosal (200 microm, 10 min) alone or combined with 6-dimethylaminopurine (2.5 mm and 3.5 h, respectively). Activation rates of the oocytes, neither from the large nor small follicles, were affected by different activation treatments (single or combined stimuli). Whereas maturation rates for the oocytes from large follicles were superior to those from small follicles in both the single (59% vs 45%) and combined treatments (76% vs 40%; p < 0.05). To understand how prolonged heat shock (HS) influences cytoskeletal configurations of mature bovine oocytes, in Experiment 2 (Exp 2), matured oocytes derived from large follicles were randomly allocated to different durations of HS treatments at 41.5 degrees C for 0 (C0h, control, n = 12), 1 (HS1h, n = 28), 2 (HS2h, n = 31), and 4 h (HS4h, n = 30). An additional control group was cultured for 4 h without HS (38.5 degrees C, 4 h, n = 35). Alterations in nuclear structures, microtubules (MTs), and microfilaments (MFs) of the oocytes were examined. Abnormalities in the chromosomes, spindle MTs and the percentages of oocytes with cytoplasmic MTs increased with time of HS treatment. The intensity of the MF distribution in the HS oocytes was also altered. Significant changes in the cytoskeleton after HS may be associated with the reduced development under hyperthermia and, perhaps, with the low pregnancy rates of the animals during hot seasons.

The effect of progestin on rabbit endometrial aromatase activity

The ability of rabbit endometrium to synthesize estrogen was investigated. Aromatase activity was measured by incubating the viable tissue fragments with [3H] testosterone at 37 degrees C and quantitated the [3H]estrogens at the end of 6 h incubation. The activity was not detectable in endometrium and myometrium of non-pregnant rabbits. In pregnant rabbit, the activity increased from 2 to 12 fmol/h/g of tissue in endometrium obtained from both gravid and nongravid uterine horns 4-8 days after mating. Aromatase activity in endometrium at implanted sites on the 8th day after mating reached up to 550 fmol/h/g of tissue. Hormonal regulation of the aromatase activity was studied directly in cultured rabbit endometrial stromal cells. Both progesterone and medroxyprogesterone acetate stimulated the activity with 2- to 25-fold increase over the control values (0.2-1 fmol/h/mg protein). The stimulation of aromatase activity by progestin was found to be both time- and dose-dependent. Estrogen, Bu2cAMP, forskolin, HCG or relaxin had no effect on the activity. Aromatase activity in glandular epithelial cells was neither detectable nor affected by progestin. These results indicate that aromatase activity in rabbit endometrium is concentrated in stromal cells and progestin stimulates the activity. However, estrogen, forskolin and relaxin which enhanced the stimulation of the activity by progestin in human endometrium had no effect on aromatase in rabbit endometrium. The increase of aromatase activity observed after the onset of conception may be physiologically important to increase the local estrogen content for decidualization of the endometrium.

Endocrine aspects of human uterine sarcoma: a preliminary study

The biologic effect of estrogen and progesterone in human uterine sarcoma is poorly understood in comparison to that of endometrial adenocarcinoma. In an attempt to elucidate the endocrine status of these tumors, we have investigated the ability of these tumors to synthesize estrogen by measuring the aromatase activity and studied the effect of aromatase inhibitors on the activity. In addition, the effect of estrogen and progesterone on aromatase activity and the growth pattern of these tumors were studied in cell culture and athymic mice systems. Aromatase activities in eight uterine sarcomas ranged from 0.7 to 37 fmol/hr X mg protein, which were within the range or higher than the activity found in normal proliferative endometrium (0.5 to 3 fmol/hr X mg of protein, means = 1.6, n = 10). These results indicate that uterine sarcomas are capable of producing estrogen. However, the enzyme activity showed no correlation with the morphology of tumors or the age of patients. Results from the kinetic studies of aromatase activity in one of the uterine sarcomas indicated that 19-nortestosterone, testolactone, and aminoglutethimide (the most effective one) inhibited aromatase activity. In addition, induction of aromatase activity in two uterine sarcomas was investigated in cell cultures. Progesterone caused an eightfold increase in activity in a sarcoma that was estrogen and progesterone receptor positive but had no effect in a tumor that was estrogen and progesterone receptor negative. The growth rate of two estrogen/progesterone receptor-negative uterine sarcomas was studied in cell culture and in athymic mice. Progestin, but not estrogen, reduced the growth rate in both systems; 30 nmol/L of estrogen had no effect on the growth rate. In summary, we have found that human uterine sarcoma is able to synthesize estrogen. Progesterone is able to induce the aromatase activity in estrogen/progesterone receptor-positive tumors, and progesterone also suppresses the tumor growth rate in estrogen/progesterone receptor-negative tumors. These results suggest that a select group of uterine sarcomas is sensitive to steroid hormone and that progesterone may be potentially beneficial for therapeutic treatment of select uterine sarcomas.

Contribution of maternal circulation to blood-borne progesterone in the fetus. II. Studies on sheep

Catheters were placed in maternal and fetal vessels in four ewes in the last month of gestation. Tritiated progesterone (P) was infused at a constant rate into a maternal peripheral vein. Specific activities and endogenous concentrations of P were measured in blood samples drawn from a maternal artery and either a fetal femoral artery or an umbilical vein. Comparison of the specific activities of P in fetal and maternal samples revealed that direct secretion of the placental hormone into the umbilical vein accounted for 90 to 93 per cent of the hormone in the fetal circulation. Estimates of the rates of production of P in the fetal circulation, obtained by multiplying metabolic clearance rates previously reported and concentrations of P in a fetal femoral artery, indicate that placental P is preferentially secreted toward the maternal circulation.

Comparison of results from in situ and in vitro perfusions of rabbit uterus with labeled estrone and estradiol

The interconversion of labeled estrone (E1) and estradiol (E2) in rabbit uterus was studied in vivo and in vitro, in order to evaluate the influence of incubation conditions upon the preferred direction of the reversible conversion of E2 to E1. In a typical experiment, one uterine horn was perfused intraluminally in situ with a mixture of [3H]E2 and [14C]E1, while the other horn was dissected and used for in vitro perfusions with the same tracers, both intraluminally and on tissue slices. The ratios of rate constants corresponding to the oxidative and reductive reactions were found to be similar under the three perfusion conditions, as calculated from the isotopic data. The rate constant of conversion of E1 to E2 was 10-20 times larger than the rate constant of the opposite reaction. Equal E2 nuclear saturation levels were obtained by perfusion of the uterine tissue with excess [3H]E2 in situ and in vitro after slicing.