Environmental contamination in the isolation rooms of COVID-19 patients with severe pneumonia requiring mechanical ventilation or high-flow oxygen therapy.

BACKGROUND: Identifying the extent of environmental contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for infection control and prevention. The extent of environmental contamination has not been fully investigated in the context of severe coronavirus disease (COVID-19) patients. AIM: To investigate environmental SARS-CoV-2 contamination in the isolation rooms of severe COVID-19 patients requiring mechanical ventilation or high-flow oxygen therapy. METHODS: Environmental swab samples and air samples were collected from the isolation rooms of three COVID-19 patients with severe pneumonia. Patients 1 and 2 received mechanical ventilation with a closed suction system, while patient 3 received high-flow oxygen therapy and non-invasive ventilation. Real-time reverse transcription-polymerase chain reaction (rRT-PCR) was used to detect SARS-CoV-2; viral cultures were performed for samples not negative on rRT-PCR. FINDINGS: Of the 48 swab samples collected in the rooms of patients 1 and 2, only samples from the outside surfaces of the endotracheal tubes tested positive for SARS-CoV-2 by rRT-PCR. However, in patient 3's room, 13 of the 28 environmental samples (fomites, fixed structures, and ventilation exit on the ceiling) showed positive results. Air samples were negative for SARS-CoV-2. Viable viruses were identified on the surface of the endotracheal tube of patient 1 and seven sites in patient 3's room. CONCLUSION: Environmental contamination of SARS-CoV-2 may be a route of viral transmission. However, it might be minimized when patients receive mechanical ventilation with a closed suction system. These findings can provide evidence for guidelines for the safe use of personal protective equipment.

The effect of horse simulator riding on visual analogue scale, body composition and trunk strength in the patients with chronic low back pain.

BACKGROUND: Chronic low back pain (CLBP) is one of the most common musculoskeletal disorders, and thus effective treatments are required. Recently, real horseback riding has been reported to be beneficial for the patients. However, it has some limitations, such as limited approaches and safety issues. OBJECTIVE: The purpose of this study was to investigate the effect of horse simulator riding on back pain, body composition and trunk strength in the patients with CLBP. PARTICIPANTS: Forty-seven men with CLBP (mean age 20.55 ± 1.38 years) were randomly divided into a control group (n = 23) and a horse simulator riding group (n = 24), and visual analogue scale (VAS), body composition and isokinetic trunk strength were measured after 8 weeks for which subjects in a horse simulator riding group had performed the horse simulator exercise (HSE). RESULTS: Horse simulator exercise significantly reduced pain scores of VAS and enhanced isokinetic torques of trunk at 30 and 90°/s. There were also significantly increased muscle mass and decreased fat mass in horse simulator riding group. CONCLUSION: It can be inferred that HSE may be helpful in relief of back pain and recovery of back function through developing trunk strength and balancing the ratio of trunk flexor/extensor muscles.

Antibacterial activity of bark of Alnus pendula against methicillin-resistant Staphylococcus aureus.

BACKGROUND AND OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) infections are a rapidly growing health problem around the globe. Recently, there has been considerable interest in the use of plant materials as an alternative method to control pathogenic microorganisms. In this study we evaluated the antibacterial activity of bark of Alnus pendula against MRSA. MATERIALS AND METHODS: The MIC determination was done using the microdilution broth method and bacterial growth was determined by measuring optical density using spectrophotometer. RESULTS: Alnus pendula bark EtOH extract and fractions (F-1, -2, -3 and -4) were investigated against MRSA. The most active fractions (F-3 and F-4) led to the isolation of oregonin (ORE) and hirsutanone (HIR). These compounds were active against MRSA strains with minimum inhibitory concentrations (MICs) ranging from 31.25 to 250 microg/ml MIC and 2 MIC of HIR completely inhibited the growth of MRSA. CONCLUSIONS: The bark EtOH extract of Alnus Pendula has potent antibacterial activity against MRSA.

Effects of valproic acid and magnesium sulphate on rocuronium requirement in patients undergoing craniotomy for cerebrovascular surgery.

BACKGROUND: Many anti-epileptics cause resistance to non-depolarizing neuromuscular blocking agents, but this has not been reported for valproic acid (VPA). We hypothesized that VPA would increase the rocuronium requirement and that magnesium sulphate (MgSO(4)) may reduce this increase. METHODS: Fifty-five patients undergoing cerebrovascular surgeries were studied. Subjects were allocated into three groups at a 1:1:1 ratio: Groups VM, VC, and C. Groups VM and VC were given VPA premedication; Group C was not. A rocuronium injection (0.6 mg kg(-1) i.v.) was administered to Group VM, followed by MgSO(4) as a 50 mg kg(-1) i.v. bolus and 15 mg kg(-1) h(-1) infusion. The same volume of 0.9% saline was administered to the other groups. Supplementary rocuronium (0.15 mg kg(-1)) was given whenever the train-of-four count reached 2. Rocuronium requirements (primary outcome), mean arterial pressure (MAP), heart rate (HR), nausea, vomiting, shivering, and use of anti-emetics and nicardipine were compared. RESULTS: Group VC showed the highest rocuronium requirement [mg kg(-1) h(-1): 0.47 (0.08) vs 0.33 (0.12) (Group C), 0.31 (0.07) (Group VM); P<0.001]. MAP, intraoperative HR, nausea, vomiting, shivering, and use of anti-emetics and nicardipine were not significantly different among the groups. Postoperative HR was lower in Group VM than in Group VC. CONCLUSIONS: VPA increased the rocuronium requirement, and MgSO(4) infusion attenuated this increase.

Daidzein supplementation prevents non-alcoholic fatty liver disease through alternation of hepatic gene expression profiles and adipocyte metabolism.

INTRODUCTION: Globally, non-alcoholic fatty liver disease (NAFLD) continues to rise and isoflavones exert antisteatotic effects by the regulation of hepatic lipogenesis/insulin resistance or adiposity/a variety of adipocytokines are related to hepatic steatosis. However, there is very little information regarding the potential effects of daidzein, the secondary abundant isoflavone, on NAFLD. Here, we have assessed the hepatic global transcription profiles, adipocytokines and adiposity in mice with high fat-induced NAFLD and their alteration by daidzein supplementation. METHODS: C57BL/6J mice were fed with normal fat (16% fat of total energy), high fat (HF; 36% fat of total energy) and HF supplemented with daidzein (0.1, 0.5, 1 and 2 g per kg diet) for 12 weeks. RESULTS: Daidzein supplementation (≥ 0.5 g per kg diet) reduced hepatic lipid concentrations and alleviated hepatic steatosis. The hepatic microarray showed that daidzein supplementation (1 g per kg diet) downregulated carbohydrate responsive element binding protein, a determinant of de novo lipogenesis, its upstream gene liver X receptor ß and its target genes encoding for lipogenic enzymes, thereby preventing hepatic steatosis and insulin resistance. These results were confirmed by lower insulin and blood glucose levels as well as homeostasis model assessment insulin resistance scores. In addition, daidzein supplementation inhibited adiposity by the upregulation of genes involved in fatty acid ß-oxidation and the antiadipogeneis, and moreover augmented antisteatohepatitic leptin and adiponectin mRNA levels, whereas it reduced the mRNA or concentration of steatotic tumor necrosis factor α and ghrelin. CONCLUSIONS: These findings show that daidzein might alleviate NAFLD through the direct regulation of hepatic de novo lipogenesis and insulin signaling, and the indirect control of adiposity and adipocytokines by the alteration of adipocyte metabolism.

Incidence and economic burden of suspected adverse events and adverse event monitoring during AF therapy.

OBJECTIVE: Rhythm- and rate-control therapies are an essential part of atrial fibrillation (AF) management; however, the use of existing agents is often limited by the occurrence of adverse events. The aim of this study was to evaluate suspected adverse events and adverse event monitoring, and associated medical costs, in patients receiving AF rhythm-control and/or rate-control therapy. RESEARCH DESIGN AND METHODS: This retrospective cohort study used claims data from the Integrated Healthcare Information Systems National Managed Care Benchmark Database from 2002-2006. Patients hospitalized for AF (primary diagnosis), and who had at least 365 days' enrollment before and after the initial (index) AF hospitalization, were included in the analysis. Suspected AF therapy-related adverse events and function tests for adverse event monitoring were identified according to pre-specified diagnosis codes/procedures, and examined over the 12 months following discharge from the index hospitalization. Events/function tests had to have occurred within 90 days of a claim for AF therapy to be considered a suspected adverse event/adverse event monitoring. RESULTS: Of 4174 AF patients meeting the study criteria, 3323 received AF drugs; 428 received rhythm-control only (12.9%), 2130 rate-control only (64.1%), and 765 combined rhythm/rate-control therapy (23.0%). Overall, 50.1% of treated patients had a suspected adverse event and/or function test for adverse event monitoring (45.5% with rate-control, 53.5% with rhythm-control, and 61.2% with combined rhythm/rate-control). Suspected cardiovascular adverse events were the most common events (occurring in 36.1% of patients), followed by pulmonary (6.1%), and endocrine events (5.9%). Overall, suspected adverse events/function tests were associated with mean annual per-patient costs of $3089 ($1750 with rhythm-control, $2041 with rate control, and $6755 with combined rhythm/rate-control). LIMITATIONS: As a retrospective analysis, the study is subject to potential selection bias, while its reliance on diagnostic codes for identification of AF and suspected adverse events is a source of potential investigator error. A direct cause-effect relationship between suspected adverse events/function tests and AF therapy cannot be confirmed based on the claims data available. CONCLUSIONS: The incidence of suspected adverse events and adverse event monitoring during AF rhythm-control and/or rate-control therapy is high. Costs associated with adverse events and adverse event monitoring are likely to add considerably to the overall burden of AF management.

Incidence and temporal pattern of hospital readmissions for patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is prevalent and has a high cost burden. Among the main drivers of cost is inpatient care; however, little is known about patterns of hospital readmissions for AF. OBJECTIVE: To evaluate the incidence and temporal pattern of readmission in AF patients. METHODS: This retrospective, cohort analysis used claims data from the Integrated Healthcare Information Systems National Managed Care Benchmark Database for 2002-2006. Patients hospitalized for AF (primary discharge diagnosis) were identified. Data on the first readmission for AF over 1 year following an index hospitalization were analyzed for chronic AF (any AF-related claims in 1 year before index hospitalization) and newly-diagnosed AF patients (no prior AF-related claims). RESULTS: Overall, 4174 patients hospitalized with primary AF were identified; 1637 had chronic AF and 2537 newly-diagnosed AF. Mean age of chronic AF patients was 62.4 years and 61.2% were male; for newly-diagnosed AF, mean age was 61.4 years and 57.8% were male. In the year following index hospitalization, 12.5% of chronic AF patients were readmitted for AF, with a mean time to readmission of 142.5 days (median 108 days). Among newly-diagnosed AF patients, 10.1% were readmitted for AF, with a mean time to readmission of 133.8 days (median 112 days). For chronic AF, 17.6%, 43.4%, and 65.8% of readmissions occurred within 1, 3, and 6 months, respectively, versus 22.7%, 44.5%, and 67.2%, respectively, for newly-diagnosed AF. LIMITATIONS: Limited data were available on patients' clinical profile, treatment patterns, or the reasons for hospitalization/readmission. The term chronic AF only captured patients with a history of AF and data were not available to classify patients according to the presence of paroxysmal, permanent, or persistent AF. CONCLUSIONS: Patients with newly-diagnosed or chronic AF are often readmitted in the year following hospitalization with most readmissions occurring within 6 months of the index hospitalization.

Protective effect of antioxidant supplementation in sperm-preparation medium against oxidative stress in human spermatozoa.

BACKGROUND: Oxidative stress induced by reactive oxygen species (ROS) is associated with an impaired fertilization ability of spermatozoa. We investigated the effects of adding antioxidants to a sperm preparation medium on the functional parameters of the spermatozoa. METHODS: Spermatozoa were washed with Ham's F-10 media containing the antioxidants, ethylenediaminetetraacetic acid (EDTA) and catalase, at various concentrations, and then the ROS levels in sperm suspensions, and the forward motility, acrosome reaction, DNA integrity and lipid peroxidation of the spermatozoa were assessed. RESULTS: The ROS levels were significantly lower in sperm suspensions washed with the antioxidants (196 approximately 312 rlu; relative light units) than in control sperm (604 rlu, P < 0.05). The addition of 10 microM EDTA to the sperm preparation medium significantly improved the motility of the spermatozoa compared with the control group, the groups containing EDTA at other concentrations and the groups containing catalase. Catalase significantly increased the acrosome reaction rate of the spermatozoa. Both EDTA and catalase significantly decreased the DNA fragmentation rate of the spermatozoa. However, the antioxidants did not reduce lipid peroxidation. CONCLUSIONS: Supplementing sperm preparation medium with EDTA or catalase significantly improved the overall functional parameters of the spermatozoa by reducing the ROS levels.

Electroacupuncture may relax the sphincter of Oddi in humans.

BACKGROUND: This study was designed to evaluate the effects of electroacupuncture on sphincter of Oddi (SO) motility in humans and to associate the manometric findings with cholecystokinin (CCK) plasma levels. METHODS: Eleven patients (M:F = 5:6) with various kinds of biliary disorders were enrolled. SO motility was monitored with conventional low-compliance, continuous perfusion technique at ERCP (n = 9) or via percutaneous transhepatic cholangioscopy (n = 2). After baseline monitoring for phasic wave contractions of SO, electroacupuncture was applied at a specific acupoint GB 34. A nonspecific acupoint 5 cm away from GB 34 was selected as a control. Manometric parameters of the SO were also measured in 6 subjects during stimulation of the control acupoint. CCK plasma levels were measured during electroacupuncture stimulation. RESULTS: All manometric parameters including basal pressure, amplitude, frequency, and duration of phasic wave contractions of the SO were significantly decreased (p < 0.05) during electroacupuncture stimulation. The inhibition of SO contractility was accompanied by increased CCK plasma levels. After discontinuation of electroacupuncture stimulation, restoration of amplitude and duration to basal conditions was noted. A tendency toward return of SO basal pressure and contractile frequency to baseline was also observed. Stimulation of the control acupoint did not affect SO contractility. CONCLUSION: Electroacupuncture stimulation of acupoint GB 34 resulted in reversible inhibition of SO contraction in humans. The response of SO to electroacupuncture stimulation may be mediated by some neurohormonal mechanisms including CCK release.

In vitro function of S rnases in Lycopersicon peruvianum.

S RNases are products of the S locus that are expressed in the stylar tissue of Lycopersicon peruvianum with the gametophytic self-incompatibility (SI) system. Two S RNases (S12 and Sa) with RNase activity from the S12Sa genotype of L. peruvianum were purified using gel filtration and cation-exchange chromatography. The molecular masses of the two RNases, S12 and Sa, were 21 and 23.1 kDa, respectively. The specific activities of S12 and Sa for torula yeast rRNA as a substrate were 8,500 and 6,000 units/ml, respectively. Of various reagents tested for RNase activities, ZnSO4 and CuSO4 were found to remarkably reduce its activity. The growth of S12Sa pollen was inhibited when it was cultured in a pollen germination medium that contained the purified S12 RNase. The result suggested that the S RNase was either a probable inhibitor of pollen growth or controlled pollen growth. Additionally, 512Sa pollens germinated well in vitro in a germination medium that contained S12 RNase in the presence of ZnSO4 and CuSO4. Our finding suggests that the treatment of S RNase with its inhibitor destroys the SI ability on an in vitro self-pollen growth test.

A brief commentary: electroacupuncture may relax the contraction of sphincter of Oddi.

Animal studies have shown that acupuncture can affect the function of the sphincter of Oddi, a smooth muscle encircling major papilla located at the second portion of the duodenum that regulates the flow of bile and pancreatic juice. This study of thirteen patients was the first to observe the effects of acupuncture on sphincter of Oddi motility in humans. Stimulation of the acupuncture point GB-34, which is known to Oriental medicine as an acupoint with effect on the biliary system, showed reversible inhibition of sphincter of Oddi contractions. In contrast, stimulation of a nonspecific control acupoint did not induce significant change. This study suggests that acupuncture may be one alternative treatment for patients with sphincter of Oddi dysfunction.

Mechanism for antiplatelet effect of onion: AA release inhibition, thromboxane A(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade.

Antiplatelet actions of aqueous extract of onion were investigated in rat and human platelet. IC(50)values of onion extract for collagen-, thrombin-, arachidonic acid (AA)-induced aggregations and collagen-induced thromboxane A(2)(TXA(2)) formation were 0.17 +/- 0. 01, 0.23 + 0.03, 0.34 +/- 0.02 and 0.12 +/- 0.01 g/ml, respectively. [(3)H]-AA release induced by collagen (10 microg/ml) in rat platelet was decreased by onion compared to control (22.1 +/- 2.13 and 5.2 +/- 0.82% of total [(3)H]-AA incorporated, respectively). In fura-2 loaded platelets, the elevation of intracellular Ca(2+)concentration stimulated by collagen was inhibited by onion. Onion had no cytotoxic effect in platelet. Onion significantly inhibited TXA(2)synthase activity without influence on COX activity. Platelet aggregation induced by U46619, a stable TXA(2)mimetic, was inhibited by onion, indicating its antagonism for TXA(2)/PGH(2)receptor. These results suggest that the mechanism for antiplatelet effect of onion may, at least partly, involve AA release diminution, TXA(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade.

Comparison of in vivo fate and immunogenicity of hepatitis B surface antigen incorporated in cationic and neutral liposomes.

To compare cationic liposomes (CatL) and neutral liposomes (NeuL), as a vaccine carrier, the in vivo fate and immunogenicity of hepatitis B surface antigen (HBsAg), incorporated in CatL and NeuL, were investigated. CatL, composed of phosphatidyl choline (PC) and stearyl amine (SA) with a molar ratio of 9:1, showed a 2.5-fold higher incorporating efficiency of HBsAg than NeuL composed of PC alone. Most of HBsAg incorporated in both liposomes existed in an antibody-available form on the outer surface of liposomes. After intramuscular injection to rats, HBsAg in CatL resided at the injection site for a longer period than that in NeuL with terminal half lives of 52.5 and 42.9 h, respectively. However, HBsAg in NeuL was more efficiently taken up by the lymphatic organs and spleen than that in CatL. Furthermore, the group treated with HBsAg in NeuL showed earlier sero-conversion with higher anti-HBsAg titre than the group treated with HBsAg in CatL. Sero-conversion rates (SCRs) in both CatL- and NeuL-treated animals were 100% after every injection carried out, except the primary injection of CatL. These results demonstrate that CatL can enhance the retention of incorporated antigen at the injection site, compared with NeuL. However, the production of antibody by HBsAg in NeuL is more effective than that by HBsAg in CatL, probably due to the higher lymphatic targeting ability of NeuL. Thus, NeuL appears to be a better carrier for HBsAg than CatL.

Cosmic ray hits in the central nervous system at solar maximum.

It has been suggested that a manned mission to Mars be launched at solar maximum rather than at solar minimum to minimize the radiation exposure to galactic cosmic rays. It is true that the number of hits from highly ionizing particles to critical regions in the brain will be less at solar maximum, and it is of interest to estimate how much less. We present here calculations for several sites within the brain from iron ions (z = 26) and from particles with charge, z, greater than or equal to 15. The same shielding configurations and sites in the brain used in an earlier paper for solar minimum are employed so that direct comparison of results between the two solar activity conditions can be made. A simple pressure-vessel wall and an equipment room onboard a spacecraft are chosen as shielding examples. In the equipment room, typical results for the thalamus are that the probability of any particles with 7 greater than or equal to 15 and from 2.3 percent to 1.3 percent for iron ions. The extra shielding provided in the equipment room makes little difference in these numbers. We conclude that this decrease in hit frequency (less than a factor of two) does not provide a compelling reason to avoid solar minimum for a manned mission to Mars. This conclusion could be revised, however, if a very small number of hits is found to cause critical malfunction within the brain.

Effects of beta-adrenergic blocking therapy on left ventricular diastolic relaxation properties in patients with dilated cardiomyopathy.

BACKGROUND: The hemodynamic mechanism for the improvement in left ventricle (LV) end-diastolic pressure in cardiomyopathy patients treated with beta-adrenergic blocking agents is controversial. We hypothesized that the salutary effect of this kind of therapy on LV end-diastolic pressure would be indicative of an improvement in late, passive diastolic relaxation properties. METHODS AND RESULTS: We studied 14 cardiomyopathy patients in normal sinus rhythm with no arteriographic evidence of coronary artery disease and an LV ejection fraction of

Activin A stimulates meiotic maturation of human oocytes and modulates granulosa cell steroidogenesis in vitro.

OBJECTIVE: To test the hypothesis that activin A promotes in vitro human oocyte meiotic maturation while inhibiting steroid secretion by nonluteinized antral granulosa cells. DESIGN: Prospective randomized controlled study. SETTING: A university medical center. PATIENT(S): Nine women ranging in age from 31-44 years who were undergoing oophorectomy for nonovarian pathology. INTERVENTION(S): Analysis of meiotic maturation of oocytes and steroid secretion by granulosa cells cultured in the presence or absence of activin A. MAIN OUTCOME MEASURE(S): Germinal vesicle breakdown (GVBD) and attainment of metaphase II (MII) in oocytes, and progesterone and E2 secretion by granulosa cells. RESULT(S): Activin A significantly enhanced GVBD (91% vs. 65%) for control and maturation to MII (56% vs. 35% for control) of immature oocytes. Activin A significantly suppressed basal, and inhibin A-and FSH-stimulated progesterone and E2 secretion by nonluteinized granulosa cells. CONCLUSION(S): Activin A is a promoter of oocyte maturation in vitro and a modulator of granulosa cell steroidogenesis in culture.

Hairpin structure of an RNA 28-mer, which contains a sequence of the enzyme component of a hammerhead ribozyme system: evidence for tandem G:A pairs that are not of side-by-side type.

An RNA 28-mer (Rz28) was obtained as a major product by in vitro transcription with T7 RNA polymerase of a promoter-template DNA, which contains a sequence for the enzyme component, RNA 24-mer (Rz24), of a mutant hammerhead ribozyme system. Sequence analysis and enzymatic probing study showed that Rz28 has 4 extra nucleotides at the 3'-terminus, the sequence of which is complementary to that of the 5'-terminal sequence of Rz24, and forms a stable hairpin structure. NMR studies using a 15N-guanine-labeled derivative suggested that Rz28 contains tandem G:A pairs that are not of the side-by-side type which is found in the crystal structure of hammerhead ribozyme complexes. Comparison of the HMQC spectra of 15N-guanine-labeled Rz28 and Rz24 suggested that Rz24 also contains the same type of tandem G:A pairs.

Inhibition of ethanol absorption byRhodiola sachalinensis in rats.

We used a herbal medicine, roots ofRhodiola sachalinensis (RS) to assess whether RS extract can decrease blood ethanol concentrations in rats fed ethanol and if so, to elucidate the mechanism by which RS extract reduces blood ethanol levels. Rats were fed ethanol orally 1 hr after the oral administration of various doses of RS extract. In another experiment, rats were injected intraperitoneally with ethanol following the intake of RS extract via gastric catheter to eliminate possible inhibition of ethanol absorption in the gastrointestine by RS extract. The administration of RS extract remarkably lowered blood ethanol levels in a dose-dependent manner in rats given ethanol orally. However, the intake of RS extract did not reduce ethanol levels in rats injected with ethanol intraperitoneally. The activities of two main hepatic enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), involved in ethanol metabolism, were not affected by the administration of RS extract in rats fed ethanol. In addition, the intake of RS extract reduced serum triglyceride levels elevated by ethanol to the normal level. We conclude that the administration of RS extract lowers blood ethanol concentrations by inhibition of ethanol absorption in the gastrointestinal tracts of ethanol-fed animals.

Pregnancy can be established in superovulated adult rats treated with progesterone and an aromatase inhibitor.

An adult superovulated rat model has been developed and is characterized by high ovulation rates, early morphological degeneration of embryos, complete embryo loss within 48 hours of conception and elevated peripheral estradiol(E2)/progesterone(P4) ratios. In this study, three trials were conducted using the superovulated adult rat model. First, control naturally cycling rats were compared with superovulated rats supplemented with 1 mg P4 on days 0-3 of pregnancy. A sperm positive vaginal smear is designated as day 0 of pregnancy. The P4 treated rats demonstrated improved embryo retrieval on day 1 of pregnancy, continued embryo recovery with a decrease in normal morphologic characteristics of integrity on day 2, with nearly total embryo loss by day 3. On each day, P4 levels were elevated 2-3 times over control. The second trial compared 3 groups of rats, 1) naturally cycling, 2) superovulated unsupplemented and 3) superovulated rats supplemented with 1 mg P4/rat/day and the aromatase inhibitor, 4-hydroxyandrostenedione (4-OHA), 12.5 mg/rat/day. The superovulated unsupplemented rats had no embryo recovery after day 2 of pregnancy, while the P4 and 4-OHA treated rats showed a variable ability to maintain normally developing embryos through day 4 of pregnancy. E2 levels were elevated in both superovulated groups on days 1-4 of pregnancy as were P4 levels on days 2-4. The E2/P4 ratio was significantly lowered only on day 1 of pregnancy in the P4 and 4-OHA treated group. The third trial demonstrated implantation in 50% of the superovulated rats supplemented with P4 and 4-OHA. In conclusion, implantation in the superovulated adult rats can occur with P4 and 4-OHA supplementation, however, this biologic phenomenon could not be explained by obvious changes in peripheral E2 and P4 levels.