Control of microbial sulfide production by limiting sulfate dispersal in a water-injected oil field.

Oil production by water injection often involves the use of makeup water to replace produced oil. Sulfate in makeup water is reduced by sulfate-reducing bacteria to sulfide, a process referred to as souring. In the MHGC field souring was caused by using makeup water with 4mM (384ppm) sulfate. Mixing with sulfate-free produced water gave injection water with 0.8mM sulfate. This was amended with nitrate to limit souring and was then distributed fieldwide. The start-up of an enhanced-oil-recovery pilot caused all sulfate-containing makeup water to be used for dissolution of polymer, which was then injected into a limited region of the field. Produced water from this pilot contained 10% of the injected sulfate concentration as sulfide, but was free of sulfate. Its use as makeup water in the main water plant of the field caused injection water sulfate to drop to zero. This in turn strongly decreased produced sulfide concentrations throughout the field and allowed a decreased injection of nitrate. The decreased injection of sulfate and nitrate caused major changes in the microbial community of produced waters. Limiting sulfate dispersal into a reservoir, which acts as a sulfate-removing biofilter, is thus a powerful method to decrease souring.

Growth and cytopathic effect of Japanese encephalitis virus in astrocyte-enriched cell cultures from neonatal mouse brains.

Neuron-free, astrocyte-enriched brain cell cultures from newborn mice could be infected with Japanese encephalitis virus (JEV) as evidenced by immunofluorescence (IF), viral replication and cytopathic effect (CPE). Virus-specific cytoplasmic fluorescence was detectable in astrocytes first after 18 hrs, released infectious progeny virus in the culture fluid after 24 hrs, and CPE after 11 days post infection (p.i.).

Clomiphene citrate therapy and unexplained subfertility.

Oestrogen receptor (ER) and progesterone receptor (PR) binding site levels were determined using an assay system based upon that of King et al. Endometrial samples were obtained from 49 subfertility patients on clomiphene citrate (Clomid) therapy admitted to hospital for dye laparoscopy. An assay system based on that of Kato and Seto using synthetic androgen R1881 was used to measure androgen receptor (AR) binding sites in endometrial tissue obtained in the above patients. It is concluded that a cyclic variation was observed in ER and PR binding sites in women on Clomid therapy. No cyclic variation was observed in AR binding sites of women on Clomid therapy.

Steroid content in endometrial tissue.

In the human endometrium, the role of C19 steroids is at present unclear. Radioimmunoassays (RIA) were developed which had sufficient specificity and accuracy to measure testosterone, 5 alpha-dihydroxytestosterone (5 alpha-DHT), oestradiol, progesterone and androstenedione in endometrial samples. Amounts of androstenedione were greater (range 1.2-20.8 ng/mg tissue) than other steroids. Samples were obtained from patients presenting conditions such as subfertility, postmenopausal bleeding, dysfunctional uterine bleeding and abdominal pain. Patients used as normals were admitted for sterilisation. A significant positive correlation (r = 0.80) was found between the levels of testosterone and 5 alpha-reductase system. No relationship was observed in tissue steroid concentration and age of the patients. Steroid concentrations were found to be high in tissue obtained from patients with endometrial carcinomas whereas progesterone concentration being low in subfertiles.

Steroid receptors and subfertility.

Oestrogen, progesterone and androgen receptor levels of endometrial issues were determined using the dextran-coated charcoal (DDC) technique from sub-fertile women. The procedure based on protamine sulphate precipitation was not used since endometrial tissue available was very small. No correlation was found between receptor binding site and day of cycle for any steroids analysed; nor was these any correlation between age and receptor binding site. In the oestrogen and progestorene receptor concentrations in the menstrual cycle, a cyclic variation was followed by normal women.