Estimation of the number of polyhydroxyalkanoate (PHA)-degraders in soil and isolation of degraders based on the method of most probable number (MPN) using PHA-film

A new method to estimate the number of polyhydroxyalkanoates (PHA)-degraders in soil and to isolate degraders, called the film-MPN method, is proposed. The incubation time was measured by the first order reaction (FOR) model. This method was used to estimate numbers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)[P(3HB-co-3HV)]- and poly(3-hydroxyvalerate-co-4-hydroxybutyrate)[P(3HB-co-4HB)]-degraders in garden soil (4.30 x 10(5) and 2.15 x 10(5) aerobic degraders per gram of dry soil, respectively). The number of P(3HB-co-3HV)-degraders in paddy field soil was 5.06 x 10(5) aerobic degraders per gram dry soil. Also, several P(3HB-co-3HV)-degraders were isolated directly from positive-growth tubes of high dilution.

Hemodynamic profiles during concurrent intraaortic balloon pumping and venoarterial bypass--a canine study comparing subclavian and femoral artery perfusion sites

Concomitant use of venoarterial bypass (VAB) with centrifugal pump and intraaortic balloon pumping (IABP) is a common technique for cardiopulmonary resuscitation. This experimental study examines whether coronary perfusion and hemodynamics are affected by the site of the blood supply, comparing the subclavian artery and the femoral artery. VAB and IABP were performed in 11 mongrel dogs with cardiopulmonary failure induced by acute myocardial infarction and hypoventilation. Aortic root pressure (AP), left atrial pressure, central venous pressure and coronary sinus blood flow (CSF) were measured, and blood gas analysis was performed. Subclavian artery perfusion (SAP) and femoral artery perfusion (FAP) were compared at bypass ratios of 25, 50, 75, 85, 100%. At bypass ratios of 75% and 85% the mean systolic AP was higher with SAP than with FAP. The mean diastolic AP was higher with SAP than with FAP at a bypass ratio of 50% or higher. CSF was higher with SAP than with FAP at a bypass ratio of 50% or higher. The coronary arteriovenous O2 content difference was lower with SAP than with FAP at a bypass ratio of 85% or higher. In conclusion, at a high bypass ratio, SAP was more effective than FAP in achieving diastolic augmentation, thus enhancing myocardial oxygen balance, even though SAP had less of a systolic unloading effect. These data support the use of SAP over FAP in patients with severe cardiopulmonary dysfunction requiring high-flow bypass, and especially in patients with myocardial ischemia.

Partial cDNA cloning and NGF regulation of a rat 5-HT3 receptor subunit

Nerve growth factor (NGF) stimulates 5-HT3 receptor expression although the mechanism(s) responsible for this effect are unknown. We report the nucleotide and deduced amino acid sequences of a nearly complete rat 5-HT3 receptor subunit and use the sequence to develop a reverse transcription-polymerase chain reaction (RT-PCR) assay that measures 5-HT3 mRNA. Exposure of PC12 cells to NGF results in increasing steady-state levels of 5-HT3 mRNA. The four-fold increase in mRNA correlates with and is sufficient to account for increases in receptor measured by agonist induction of whole cell currents.

Enzyme-histochemical method for identification of lymphatic capillaries

Using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining, lymphatic capillaries and blood capillaries were distinguished histochemically on cold glycol methacrylate (JB-4) sections of monkey intestines, on the basis of both enzyme characteristics. The specificity of the 5'-Nase reaction was obtained by inhibiting nonspecific ALPase in the 5'-Nase incubation medium including L-tetramisole. This double staining method demonstrated satisfactory isolated visualization of 5'-Nase activity in lymphatic capillaries and of ALPase activity in blood capillaries under light microscopy. The intensity and localization of 5'-Nase activity on the walls of lymphatic capillaries were also determined by the lead-based method under transmission electron microscopy. The intense reaction products of 5'-Nase activity were predominantly deposited on the outer surface of the plasma membrane of the lymphatic endothelial cells.