Effect of amiloride and surfactant on lung liquid clearance in newborn rabbits

Immature and nearly mature fetal rabbits (gestational age 27.5 and 29.5 days, respectively) were obtained by hysterotomy and tracheotomized at birth. Immature rabbits received, via the tracheal cannula, 2.5 ml/kg of either normal saline, porcine surfactant (60 mg/ml), 1 mM amiloride in normal saline, or a mixture of surfactant and amiloride; nearly mature rabbits received either normal saline, or 1 mM amiloride in saline. The neonates were ventilated with a tidal volume of approximately 10 ml/kg for 0-60 min (immature animals) or 0-120 min (nearly mature animals). The lungs were then excised for determination of wet lung weight/body weight ratio (LW/BW). The right lung was further processed for quantification of extravascular lung water (EVLW) per unit dry lung weight, and the left lung fixed for measuring the size of perivascular 'cuffs' (adventitial tissue including lymphatics) in histological sections, using vascular lumen as reference volume. Immature animals receiving surfactant had improved compliance and smaller perivascular cuffs in comparison with the other groups. In immature animals amiloride had no effect on compliance, LW/BW, and EVLW, but reduced perivascular cuff size at 15 min. Nearly mature animals receiving amiloride had higher values for LW/BW and EVLW at 120 min, and lower perivascular cuff size at 15, 60, and 120 min, in comparison with saline-treated litter-mates. We conclude that surfactant improves lung-thorax compliance and reduces perivascular fluid accumulation in immature newborn animals without influencing total lung water content, and that amiloride retards fetal lung liquid resorption in nearly mature newborn animals without affecting lung-thorax compliance during artificial ventilation.

Antenatal ambroxol effects on surfactant pool size and postnatal lung function in preterm ventilated rabbits

Following maternal treatments with 50 mg/kg/day ambroxol for 2 or 3 days before delivery at 28 days gestation, preterm rabbits were ventilated to evaluate lung function. Subsequently, surfactant saturated phosphatidylcholine (SatPC) pool sizes were measured. One half of the ambroxol treated and control rabbits were given surfactant at delivery. Although surfactant improved lung function comparably for control and ambroxol treated rabbits, ambroxol treatments did not change ventilatory pressure requirements, compliances, or the recovery of intravascular labeled albumin in the lungs. Ambroxol treatments tended to increase lung volumes as evaluated by pressure-volume curves. The ambroxol treatments significantly increased lung tissue SatPC by 22%, but there were no changes in alveolar SatPC pool values. These results do not indicate a large effect of ambroxol on lung function in preterm rabbits.

[An experimental research on the acute lung injury induced by endotoxin]

Using a goat endotoxin model with chronic lung lymph fistula, we continuously measured lung lymph flow (QL), lymph to plasma protein ratio (L/P), pulmonary arterial pressure (Ppa) and the level of thromboxane B2 in plasma and lymph. We also observed the changes of ultrastructure in leukocyte and pulmonary parenchyma. It showed that the alteration can be divided into two intervals: phase I is characterized by the abrupt onset of pulmonary hypertension and in phase II, the capillary permeability increased predominantly. It was suggested that this model is a good research tool for studying adult respiratory distress syndrome (ARDS).

Studies on monoclonal anti-idiotypic and anti-isotypic antibodies against leukemia and myeloma: III. Analysis of monoclonal antibodies recognizing the antigenic epitopes by use of ELISA additivity test and microcomputer grouping programme

ELISA double antibodies additivity test was employed to identify the epitopes which can be recognized by monoclonal antibodies (McAbs) against IgM of a patient with B chronic lymphocytic leukemia (B-CLL). The computer grouping programme analysis showed that 4 anti-isotype McAbs could be divided into two groups and 10 anti-idiotype McAbs could be divided into four groups. The result was consistent with that of the indirect ELISA, ELISA sandwich as well as ELISA inhibition test. The above findings suggested that there are at least 6 distinct IgM epitopes which can specifically react with 14 McAbs. Our study indicated that the combination of the ELISA additivity test and the computer grouping programme analysis provides a helpful tool for researchers into the relationship between the structure and function of antigens.

[Airway challenge test with propranolol]

We investigated airway response to propranolol in 48 asthmatics, 17 subjects with chronic bronchitis and 19 normal subjects. The positive rate for propranolol challenge was 93.8% in asthma group, 5.9% in chronic bronchitis group while none in normal group had positive response. The challenge was highly reproducible, and it had few side-effects. This indicated that the challenge was specific and sensitive in diagnosis of asthma, it was a safe, reliable method of measuring non-specific airway responsiveness. Furthermore we also demonstrated that PC20 for propranolol did not relate to PC20 for methacholine, and that the calibre of airway did not significantly influence the airway response to propranolol.

Influence of cirrus clouds on the VISSR atmospheric sounder-derived sea surface temperature determinations

Using a more realistic cirrus cloud model, the characteristics of transmittance, emittance, and optical thickness and their relationships to cirrus in a diverse set of cases are studied by solving the equation of transfer of IR radiation. The doubling method is employed in the multiple scattering calculation. The satellite-observed brightness temperatures for different cases are computed, and stepwise regression analyses are performed to yield retrieval equations for sea surface temperature (SST). It is shown that the radiative properties of cirrus depend strongly on particle concentration, thus on the optical thickness of clouds. For clear atmospheres, channel 8 (11.2 microm) is more transparent than other channels. For cirrus clouds only, when the optical thickness of cirrus tau(c) is <0.10, channel 8 is still more transparent, while, with tau(c) increasing from 0.2 to between 4 and 8, channel 12 (4 microm) becomes the most transparent. When tau(c) >/= 8, the transparency of channel 12 decreases and those of other channels increase. For a very large r, the transparency of VAS channels will become almost equal. In addition, the IR absorption emittance of cirrus and the brightness temperatures also have sensitivities to different cloud optical thicknesses. The general retrieval equation for the determinations of SST, which is suitable for the clear air model as well as for the cirrus cloud atmospheres (with our definition of cirrus), is obtained through a combination of channels 12, 8, 6 (4.5 microm), and 5 (13.3 microm).The retrieval error is <1.0 K. The error analyses indicate that the clear air retrieval equations should not be used for SST determination in cirrus conditions.

[Ultrasonically nebulized hypertonic saline as a provocation agent in asthmatics]

We investigated nonspecific reactivity to inhaled aerosol of hypertonic saline. Hyperosmotic challenge carried out with NaCl solution of 0.9-fold increasing concentration from 2.7 to 7.2%. Each aerosol inhalation at different concentration was carried out for 5 min. An ultrasonic nebulizer was used to generate aerosol of NaCl solution that was delivered by tubing to a two-way valve. FEV1 was measured 1.0, 1.3 and 2 min after each concentration and did further at 5 min intervals until the value reached a plateau or began to rise. The challenge was terminated when the percentage fall in FEV1 was greater than 20%. The response to HS was expressed as PC20. In the 26 subjects with stable asthma 23 were responsive to HS. The PC20-HS was from 1.65 to 6.06%. The peak bronchoconstrictor effect of HS inhalation occurred 3 min after inhalation and its mean duration was 45 min. We also compared bronchial response to HS with that to methacholine (MCH). There was a significant correlation between PC20-HS and PC20-MCH (r = 0.538, P less than 0.01). The method used for HS challenge is simple, rapid, inexpensive and provide a new means for determination of bronchial hyperreactivity.

Application of a new ventilator-multi-plethysmograph system for testing efficacy of surfactant replacement in newborn rabbits

We applied a new ventilator-multi-plethysmograph system to evaluate the effect of surfactant replacement in newborn rabbits under well controlled, nearly physiological conditions characterized by normal ECG and adequate PCO2 in right ventricular heart blood obtained at the end of the experiment. Up to 10 animals were ventilated in parallel with a pressure-constant common respirator system. Using a working pressure of 4.9 kPa (50 cmH2O), we could adjust the pressure delivered to each animal within the range of 0.49-4.4 kPa (5-45 cmH2O), by changing the length of an open high-resistance tube constituting the outflow limb of the connection between the common ventilator tube and the tracheal cannula. Immature newborn animals obtained after 27.5 days gestation and ventilated for 30 min with a tidal volume of 8-10 ml.kg-1 had a mean +/- SD lung-thorax compliance of 4.2 +/- 1.1 ml.kPa-1.kg-1 (0.41 +/- 0.11 ml.cmH2O-1.kg-1) and PCO2 of 8.5 +/- 1.9 kPa. In littermates treated at birth with a large dose of natural surfactant (Curosurf, 200 mg.kg-1, compliance increased to 6.0 +/- 1.0 ml.kPa-1.kg-1 (0.68 +/- 0.10 ml.cmH2O-1.kg-1) (p less than 0.01) and PCO2 decreased to 6.9 +/- 1.2 kPa (p less than 0.01). Near-term animals, obtained at 30 days gestation and ventilated under similar conditions had a compliance of 7.2 +/- 0.9 ml.kPa-1.kg-1 (0.71 +/- 0.09 ml.cmH2O-1.kg-1) and PCO2 of 6.4 (1.2) kPa. Administration of surfactant (same dose as above) to these mature animals at birth had no adverse effects.

Application of a new ventilator-multi-plethysmograph system for testing efficacy of surfactant replacement in newborn rabbits

We applied a new ventilator-multi-plethysmograph system to evaluate the effect of surfactant replacement in newborn rabbits under well controlled, nearly physiological conditions characterized by normal ECG and adequate PCO2 in right ventricular heart blood obtained at the end of the experiment. Up to 10 animals were ventilated in parallel with a pressure-constant common respirator system. Using a working pressure of 4.9 kPa (50 cmH2O), we could adjust the pressure delivered to each animal within the range of 0.49-4.4 kPa (5-45 cmH2O), by changing the length of an open high-resistance tube constituting the outflow limb of the connection between the common ventilator tube and the tracheal cannula. Immature newborn animals obtained after 27.5 days gestation and ventilated for 30 min with a tidal volume of 8-10 ml.kg-1 had a mean +/- SD lung-thorax compliance of 4.2 +/- 1.1 ml.kPa-1.kg-1 (0.41 +/- 0.11 ml.cmH2O-1.kg-1) and PCO2 of 8.5 +/- 1.9 kPa. In littermates treated at birth with a large dose of natural surfactant (Curosurf, 200 mg.kg-1, compliance increased to 6.0 +/- 1.0 ml.kPa-1.kg-1 (0.68 +/- 0.10 ml.cmH2O-1.kg-1) (p less than 0.01) and PCO2 decreased to 6.9 +/- 1.2 kPa (p less than 0.01). Near-term animals, obtained at 30 days gestation and ventilated under similar conditions had a compliance of 7.2 +/- 0.9 ml.kPa-1.kg-1 (0.71 +/- 0.09 ml.cmH2O-1.kg-1) and PCO2 of 6.4 (1.2) kPa. Administration of surfactant (same dose as above) to these mature animals at birth had no adverse effects.

Neutrophil-specific antigen NB1 is anchored via a glycosyl-phosphatidylinositol linkage

Neutrophil-specific alloantibodies and the antigens they recognize are important in clinical medicine but little is known about the structure of these antigens. Alloimmunization to the antigen NB1 is a clinically important cause of neonatal neutropenia and leukocyte-mediated transfusion reactions. A novel mechanism of protein attachment to cell membranes involving the covalent linkage of the protein through an oligosaccharide to phosphatidylinositol has recently been defined. Many proteins which are anchored to the cell membrane by this mechanism can be released by treatment with phosphatidylinositol-specific phospholipase C (PI-PLC). The 58-64-kDa human neutrophil surface protein which contains the NB1 antigen was labeled with 125I by using lactoperoxidase and examined for PI-PLC sensitivity. The 58-64-kDa protein was specifically released from the cell by treatment with PI-PLC, and the mobility of the protein under non-denaturing conditions using non-ionic detergent was increased by treatment with PI-PLC. Surface expression of the NB1 antigen was slightly up-regulated by treatment with the chemotactic peptide f-met-leu-phe. Removal of N-linked carbohydrates with endoglycosidase-F decreased the apparent molecular weight of the protein to approximately 45-kDa. The data suggest that most of the 58-64-kDa protein bearing the neutrophil-specific antigen NB1 is anchored to the membrane through a glycosyl-phosphatidylinositol linkage.

Immunomodulation of musk-moxa-string therapy in patients with scrofula

The effects of musk-moxa-string therapy on the immune system in man were investigated in 39 patients with scrofula. Before treatment, the numbers of peripheral blood (PB) CD3+ and DC4+ cells and the ratio CD4+/CD8+ were found to be lower in patients with scrofula than in normal subjects, while those of B cells and DR+ cells were higher. Response of peripheral blood mononuclear cells (PBMC) to phytohemagglutinin (PHA) diminished in patients with scrofula. At month 2-6 of musk-moxa-string therapy the number of PB CD8+ cells showed slight diminution along with significant increases in CD3+ and CD4+ cells and CD4+/CD8+ ratio in total lymphocytes (P less than 0.001). In vitro a marked increased blastogenic response to mitogen stimulation with PHA was observed in PBMC of patients with scrofula after treatment (P less than 0.001). In contrast, B lymphocytes, monocytes, DR+ cells and blastogenic response to concanavalin A and pokeweed mitogen were not influenced by musk-moxa-string therapy.

Studies on monoclonal anti-isotypic and anti-idiotypic antibodies against leukemia and myeloma: II. Preparation and characteristics of monoclonal anti-isotypic antibodies to IgM from B chronic lymphocytic leukemia

Five hybridomas producing McAbs against human serum IgM-isotype were obtained by fusing the myeloma NS-1 cell and the BALB/C murine spleen cell which had been immunized by serum IgM of patient with B chronic lymphocytic leukemia (B-CLL). These McAbs only reacted with human IgM, not with other immunoglobulins in ELISA and immune double diffusion test. An approximate positive rate of peripheral blood lymphocyte (PBL) was got when these McAbs and the McAbs against B cell were tested by indirect immunofluorescent assay. The positive rate was similar to that obtained by direct immunofluorescent test. Immunoblotting showed that the molecular weight of the antigen to these McAbs was 70-90 Kd, indicating that the antigen was IgM. The practical value of the McAbs against human IgM was also discussed.

Blood supply of the flexor digital tendon in the hand and its clinical significance

An anatomical study on the blood sources and vascularity of the flexor digital tendon was conducted in the upper extremities of fresh cadavers by means of arterial injection and meticulous dissection of the transparent tendon under the microscope. According to whether or not synovial membrane surrounded the tendon, the flexor digital tendon can be divided into 2 regions: non-synovial and synovial. The major intrinsic blood supply of the digital tendon was in the form of longitudinal vascular bundles, while the transverse anastomotic branches were short and sparse. The non-synovial region of the tendon was covered by paratenon and the vascular distribution of this region was uniform. In the synovial sheath, the blood vessels distributed only on the dorsal side, while the volar side was devoid of vessels. The profundus and superficialis tendons had an avascular zone at the proximal interphalangeal and metacarpophalangeal joints respectively. It was considered that the difference of the vascular architecture might be related to the mechanical force to which the tendon was subjected. The nutrition of tendon was discussed and the selection of tendon graft at operation was suggested.

[An identification method for mineral drugs]

This paper is a report on a method for chemical identification of 58 mineral drugs. Combined with the Chinese traditional identification, the method can differentiate the sham and genuine drugs in a few minutes.

[Decompensation of physiologic hypocalcemia in infants inducing vitamin D deficiency rickets]

43 infants taking the same dosage of vitamin D and calcium were investigated. The results showed that vitamin D deficiency rickets (VDR) were still present in some infants when vitamin D was sufficient, because of deficiency of 1,25-dihydroxyvitamin D (1,25-(OH)2D3). Serum calcium, phosphorus, alkaline phosphatase, triiodothyronine (T3), thyroxine (T4), calcitonin (CT), immunoreactive parathyroid hormone (iPTH), and 25-hydroxyvitamin D (25 OHD3) concentrations were compared among infants with normal, VDR of the early and recovering stages. The decompensation of physiological hypocalcemia in infants is probably the real cause of VDR and the decompensation is correlated closely with the development of parathyroid gland. This new concept is raised both at home and abroad. More practical methods for the treatment and prevention of VDR are suggested.

[A study on distribution characteristics of viral hepatitis and preventive strategy in Hangzhou]

By using the method of predictive survey, 1248 cases of acute viral hepatitis, which have been definitely diagnosed, in urban district, water-net areas, semi-mountainous and mountainous areas in Hangzhou were studied for the epidemiology and serum pathogenic typing in 1987. As a result, with the mixed infection of hepatitis A and hepatitis B at the rate of 1.20%, hepatitis A 69.71%, hepatitis B 7.13% non A non B hepatitis amounted to 21.96%. In urban and rural area, the percentage of hepatitis A ranked first while that non A non B hepatitis did second. The main risky factors in epidemicity of hepatitis A were: 1) the use of commode; 2) contact with the patients with hepatitis; 3) drinking unboiled water. Hepatitis A and hepatitis B transmitted mainly in the way of extra-intestines. Seeing dentist was the main risky factor. The relevant strategy was presented on the bases of the above-mentioned data.

Studies on monoclonal anti-idiotypic antibodies to human B cell leukemia

Murine immunocytoma cell line, NS-1, was fused with spleen cells of Balb/C mice which had been stimulated by tolerogenic disaggregated human gamma globulin and immunized by purified serum IgM from the patient with chronic B cell leukemia (B-CLL). 10 hybridoma cell lines secreting monoclonal anti-idiotype (anti-Id) antibodies to human CLL were obtained. The McAbs were subclasses belonging to IgM and of IgG mouse. Specificity and biologic characters of the monoclonal anti-Id antibodies from culture fluid or ascites were assayed by ELISA, indirect mixed ELISA sandwich, ELISA inhibition, immunofluorescence (IF) and IF inhibition. The study also proved that monoclonal anti-Id antibodies could react with homologous IgM, but not with Ig from normal donors or a panel of patients with myeloma. The results of IF and IF inhibition assay showed that monoclonal anti-Id antibodies were bound to lymphocytes of patient with B-CLL. Their reactivity was inhibited by homologous IgM, but not by lymphocytes of patients with ALL or lymphoma. Monoclonal anti-Id antibodies were heterogenous reactive patterns with cell lines in vitro.

Studies on biological characteristics and modulating factors of long-term cultured bone marrow cells of a myeloma patient in vitro

In the present study we cultured in vitro bone marrow cells from a patient with multiple myeloma (IgD) and researched into the modulation of supernatant media of various leukemic lines on the growth of culture cells. Cells in the cultures were studied for their morphological, biochemical, immunological and ultrastructural features. Drug sensitivity assay was also performed. The results showed that supernatant media of 6 cell lines promoted cell growth, but most remarkable stimulating activity was displayed by supernatant media from U937 and CEM. Cell cloning effect attained to more than 90%. Cultured cells possessing biological characteristics of malignant cells were probably malignant cells from B cell lineage. This study indicated that long-term cultures of marrow cells might provide a tool useful for clinical and laboratory purpose and a method for studies on pathogenesis, regulation of hematopoiesis, cell differentiation and guide-way drugs.

Studies on lymphocyte subpopulations and NK cell activities in epileptic patients

The subpopulations of T lymphocytes, B lymphocytes and macrophages of the peripheral blood in 58 cases of epilepsia were studied with McAb by IFA method. The activity of natural killer (NK) cells of peripheric blood monocyte was investigated by 51Cr-releasing method. 22 healthy donors of about the same age served as controls. The results showed that the percentage of T3 and T4 lymphocytes in epileptic patients was decreased, and the ratio of T4/T8 was markedly reduced as compared to control group. The percentage of T8 lymphocytes was increased. There were no significant changes in B lymphocytes and macrophages. The NK cell activity also showed decrease. The results suggested abnormality in cellular immunity in epilepsia, which may be involved in the pathogenetic mechanism of the disease.

A Study of Regular Education for Low Vision Children in a Chinese School for the Blind

The subjects of this study were 135 pupils of the Shanghai Blind Children's School. Congenital cataract led in the causes of blindness, optic atrophy came second, and microcornea and microphthalmus were third. Among the pupils 74 (54.8%) were totally blind, 56 (41.5%) were low-vision and 5 (371%) had vision of 0.3–0.4. A total of 83 pupils were considered to have usable residual vision for regular education with visual aids. Of the 83, 30 in 3 classes were followed up for two to four semesters, and teaching results were found to be good. None of the students’ conditions deteriorated during that period.

The relationship between structural features of peripheral nerves and suture methods for nerve repair

Based on techniques for identifying and distinguishing motor, sensory, and mixed fasciculi in peripheral nerves, the authors propose guidelines for selecting suture methods for nerve repair. When many mixed fasciculi are known to exist at the nerve lesion, epineurial repair is preferable; fascicular (perineurial) repair is more suitable when pure motor and sensory fasciculi are clearly recognized. Generally, epineurial repair is indicated for more proximal injuries, with fascicular repair most appropriate for more distal sites. A greater ratio of epineurial connective tissue to intrafascicular nervous tissue implies an inclination toward fascicular repair.

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.

Anatomical analysis of the cause of skin necrosis of the great toe after transplantation of the great toe nail flap

Necrosis of skin on the medial side of the great toe has been a significant complication of the great toe nail flap. To investigate the reason for this, a study of the blood supply of the medial side of the great toe was carried out on 55 feet with the injection of red latex into the arteries and on 13 vascular cast specimens. It was found that, after the blood vessels from the plantar and dorsal sides of the great toe are severed during the operation, the skin of the medial side of the great toe is mainly supplied by the medial vascular network at the head of the first metatarsal bone. It is clear that the blood supply from this network may sometimes be insufficient to nourish the skin. It is suggested that the operative incision should be changed so as to increase the blood supply to the medial vascular network which may decrease the incidence of skin necrosis.

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.

Modulation of aromatase activity in human endometrial stromal cells by steroids, tamoxifen and RU 486

The regulation of aromatase activity (AA) in human endometrial stromal cells by various steroids was studied in primary cell culture. Various progestins, but not androgens or glucocorticoids, stimulated AA. Medroxyprogesterone acetate (MPA) was the most potent progestin. Estrogen (E) alone did not change the activity but it potentiated the stimulation of AA by progestin. Biphasic regulation of AA by progestin was noted in both time- and dose-dependent manners. Endometrial AA was stimulated by MPA and reached the maximum rate between 2-5 days of incubation with subsequent decline of AA in prolonged culture. When stromal cells were treated with MPA (0.03 to 30 microM) for 3 days, AA was increased over the control at all the concentrations tested. The maximum was found at doses between 0.1-1 microM. The activities reduced steadily from the maximum stimulation to less than 50% when the concentration of MPA increased from 1-30 microM. In addition, initial treatment of stroma cells with MPA (1-3 days) resulted in further increase of activity after progestin withdrawal. The enhancement of the induction of AA by E did not alter the biphasic pattern regulated by progestin alone, i.e. E enhanced both the stimulation and the decay of AA. The time study of the effect of E showed that enhancement of AA required at least 10 h of incubation of E with MPA conditioned cells. The effect of E is dose dependent between 0.04-40 nM and shows the greatest effect in the presence of MPA between 0.01-1 microM. The optimal concentrations of E and progestin that stimulate AA in culture are similar to the plasma concentrations after pregnancy, suggesting that the physiological function of the endometrial aromatase is at the time of decidualization. The effects of antiprogestin, Ru 486, and antiestrogen, tamoxifen (TAM), on AA were studied. Ru 486 or TAM alone did not alter AA. Ru 486 inhibited the MPA stimulated AA in a dose-dependent manner suggesting that the effect of progestin may be mediated through a receptor mechanism. Enhancement, but no inhibitory effect, was observed when cells were treated with TAM + MPA and TAM + MPA + E. The effectiveness of Ru 486 to inhibit the induction of AA in endometrial cells may be of primary importance for contraception.