Elevation of superior vena caval pressure increases extravascular lung water after endotoxemia

In many sheep Escherichia coli endotoxin results in pulmonary hypertension, increased microvascular permeability, pulmonary edema, and increased central venous pressure. Since lung lymph drains into the systemic veins, increases in venous pressure may impair lymph flow sufficiently to enhance the accumulation of extravascular fluid. We tested the hypothesis that, following endotoxin, elevating the venous pressure would increase extravascular fluid. Thirteen sheep were chronically instrumented with catheters to monitor left atrial pressure (LAP), pulmonary arterial pressure (PAP), and superior vena caval pressure (SVCP) as well as balloons to elevate LAP and SVCP. These sheep received 4 micrograms/kg endotoxin, and following the pulmonary hypertensive spike the left atrial balloon was inflated so that (PAP + LAP)/2 = colloid osmotic pressure. It was necessary to control PAP + LAP in this way to minimize the sheep-to-sheep differences in the pulmonary hypertension. We elevated the SVCP to 10 or 17 mmHg or allowed it to stay low (3.2 mmHg). After a 3-h period, we killed the sheep and removed the right lungs for determination of the extravascular fluid-to-blood-free dry weight ratio (EVF). Sheep with SVCP elevated to 10 or 17 mmHg had significant increases in EVF (5.2 +/- 0.1 and 5.6 +/- 1.2) compared with the sheep in which we did not elevate SVCP (EVF = 4.5 +/- 0.4). These results indicate that sustained elevation in central venous pressure in patients contributes to the amount of pulmonary edema associated with endotoxemia.     

Positive effort dependence of maximal expiratory flow

The maximal expiratory-flow volume (MEFV) curve in normal subjects is thought to be relatively effort independent over most of the vital capacity (VC). We studied seven normal males and found positive effort dependence of maximal expiratory flow between 50 and 80% VC in five of them, as demonstrated by standard isovolume pressure-flow (IVPF) curves. We then attempted to distinguish the effects of chest wall conformational changes from possible mechanisms intrinsic to the lungs as an explanation for positive effort dependence. IVPF curves were repeated in four of the subjects who had demonstrated positive effort dependence. Transpulmonary pressure was varied by introducing varied resistances at the mouth but effort, as defined by pleural pressure, was maintained constant. By this method, chest wall conformation at a given volume would be expected to remain the same despite changing transpulmonary pressures. When these four subjects were retested in this way, no increases in flow with increasing transpulmonary pressure were found. In further studies, voluntarily altering the chest wall pattern of emptying (as defined by respiratory inductive plethysmography) did however alter maximal expiratory flows, with transpulmonary pressure maintained constant. We conclude that maximal expiratory flow can increase with effort over a larger portion of the vital capacity than is commonly recognized, and this effort dependence may be the result of changes in central airway mechanical properties that occur in relation to changes in chest wall shape during forced expiration.     

The use of catheter-tipped pressure transducers for chronic measurement of genital tract pressures in the ewe. II. Effects of oxytocin and prostaglandin F(2)alpha

Chronic catheterisation of the uterus, ampulla, and abdomen was performed in five ewes using solid-state, catheter-tipped pressure transducers. The catheters remained in place for up to 129 d, allowing in vivo studies of the effects of oxytocin and prostaglandin F(2)alpha (PGF(2)alpha). These agents did not produce any measurable increase in abdominal pressure. Intravenous (i.v.) oxytocin elicited a rapid increase in work done by both the uterus and ampulla. Intramuscular (i.m.) PGF(2)alpha produced a delayed uterine response but little change in the ampulla; i.v. PGF(2)alpha produced a rapid response at both sites. Low plasma progesterone concentrations (< 0.5 ng/ml) were associated with a greater uterine and ampullary response to oxytocin and with an enhanced uterine response to PGF(2)alpha. However, the uterine tube response to intravenous PGF(2)alpha was greatest when plasma progesterone concentrations were high.     

Involvement of organic molybdenum compounds in the interaction between copper, molybdenum, and sulfur

The effect on Cu metabolism of two organic Mo compounds, cysteine-Mo (CM) and cysteine-Mo-S (CMS), and of an inorganic compound, tetrathiomolybdate (TTM), was investigated in sheep. Intravenous administration of CMS or TTM increased total plasma Cu concentrations and promoted the appearance of trichloroacetic acid (TCA)-insoluble Cu in plasma. Plasma Mo was increased by both compounds. Column chromatography of plasma showed that CMS caused the accumulation of TCA-insoluble Cu in high-MW fractions, whereas TTM increased the Cu content of low-MW fractions, mainly albumin. CMS and TTM increased the concentration of Cu and Mo in kidney. In liver, Mo concentrations were elevated by both CMS and TTM, and Cu concentrations were reduced by TTM when it was given at a low dose rate. The subcellular distribution of Cu and Mo in liver and kidney was investigated. The findings are discussed in relation to the proposal that Mo-containing, organic compounds are intermediaries in the interaction between Cu, Mo, and S in ruminants.     

Normal T cell development is possible without ''functional'' gamma chain genes.

The T cell-specific gamma gene family is organized into four V, J and C gene segments containing clusters (gamma 1, gamma 2, gamma 3, gamma 4) in germline DNA. We found that the V, J and C elements of gamma 2 are physically linked on a stretch of 6 kb of DNA while those of gamma 3 are found within a 15-kb region. Rearrangements take place only within the clusters, explaining the rigid rearrangement patterns seen in T lymphocytes. New V gamma, J gamma and C gamma gene segments were discovered and characterized allowing the better understanding of the potential germline diversity of the gamma gene family. No correlation with T cell function, i.e. cytolytic or helper, and the type of the productive gamma rearrangement could be established. In contrast we found that functional T cell clones have been able to mature without any functional gamma chain genes.     

Effects of cold stress and exercise on fat loss in females

A Latin Square design has been used to test the responses of 24 relatively fit young women to 200 minute bouts of exercise performed over 5 day trials under each of three different ambient conditions: 15 degrees C (warm-warm; (WW)); -20 degrees C while inhaling, from a facemask, air heated to 18 degrees C (cold-warm; (CW)); and -20 degrees C (cold-cold; (CC)). In both of the cold environments, special clothing and boots were provided (insulation 0.47 degree C X watt-1 X m-2 and 0.62 degree C X watt-1 X m-2; (4 and 3 CLO units)). All three trials led to a small (0.6-0.7 degree C) rise of rectal temperature, but in the two cold environments mean body temperatures fell by over 1.0 degree C. A large increase of serum ketones occurred under all conditions, and the exercise respiratory quotient suggested some increase of fat utilization, WW (0.85) through CW (0.84) to CC (0.83). A fat loss of about 0.5 kg over the five days was confirmed by hydrostatic weighing and measurement of skinfold thicknesses. This was much less than the change previously observed in men, and moreover, it seemed to be independent of ambient conditions. Possible reasons why cold did not increase fat loss in these women include: a lower relative intensity of exercise; a greater stability of fat stores in women; avoidance of caffeine; a possible translocation of subcutaneous fat to deep fat depots; and a greater desire to "lose weight" irrespective of environmental conditions.     

Production of Methyl Ketones from Secondary Alcohols by Cell Suspensions of C2 to C4n-Alkane-Grown Bacteria

Nineteen new C₂ to C₄n-alkane-grown cultures were isolated from lake water from Warinanco Park, Linden, N.J., and from lake and soil samples from Bayway Refinery, Linden, N.J. Fifteen known liquid alkane-utilizing cultures were also found to be able to grow on C₂ to C₄n-alkanes. Cell suspensions of these C₂ to C₄n-alkane-grown bacteria oxidized 2-alcohols (2-propanol, 2-butanol, 2-pentanol, and 2-hexanol) to their corresponding methyl ketones. The product methyl ketones accumulated extracellularly. Cells grown on 1-propanol or 2-propanol oxidized both primary and secondary alcohols. In addition, the activity for production of methyl ketones from secondary alcohols was found in cells grown on either alkanes, alcohols, or alkylamines, indicating that the enzyme(s) responsible for this reaction is constitutive. The optimum conditions for in vivo methyl ketone formation from secondary alcohols were compared among selected strains: Brevibacterium sp. strain CRL56, Nocardia paraffinica ATCC 21198, and Pseudomonas fluorescens NRRL B-1244. The rates for the oxidation of secondary alcohols were linear for the first 3 h of incubation. Among secondary alcohols, 2-propanol and 2-butanol were oxidized at the highest rate. A pH around 8.0 to 9.0 was found to be the optimum for acetone or 2-butanone formation from 2-alcohols. The temperature optimum for the production of acetone or 2-butanone from 2-propanol or 2-butanol was rather high at 60°C, indicating that the enzyme involved in the reaction is relatively thermally stable. Metal-chelating agents inhibit the production of methyl ketones, suggesting the involvement of a metal(s) in the oxidation of secondary alcohols. Secondary alcohol dehydrogenase activity was found in the cell-free soluble fraction; this activity requires a cofactor, specifically NAD. Propane monooxygenase activity was also found in the cell-free soluble fraction. It is a nonspecific enzyme catalyzing both terminal and subterminal oxidation of n-alkanes.     

Anaerobic Degradation of Cyanuric Acid, Cysteine, and Atrazine by a Facultative Anaerobic Bacterium

A facultative anaerobic bacterium that rapidly degrades cyanuric acid (CA) was isolated from the sediment of a stream that received industrial wastewater effluent. CA decomposition was measured throughout the growth cycle by using a high-performance liquid chromatography assay, and the concomitant production of ammonia was also measured. The bacterium used CA or cysteine as a major, if not the sole, carbon and energy source under anaerobic, but not aerobic, conditions in a defined medium. The cell yield was greatly enhanced by the simultaneous presence of cysteine and CA in the medium. Cysteine was preferentially used rather than CA early in the growth cycle, but all of the CA was used without an apparent lag after the cysteine was metabolized. Atrazine was also degraded by this bacterium under anaerobic conditions in a defined medium.     

Neuroendocrine response to cold in Raynaud's syndrome

Eleven patients with Raynaud's syndrome accompanied by monospecific IgG ANA, nine patients with Raynaud's syndrome in the absence of ANA, and nine normal volunteers were exposed to an ambient cold challenge during which time venous blood was continuously sampled. ANA negative patients were shown to have significantly higher levels of cortisol during a cold challenge than either ANA positive patients or normal controls, and exhibited significantly lower levels of plasma norepinephrine compared with normal controls. ANA positive patients did not differ significantly from normals in their neuroendocrine response to cold. It is suggested that the high plasma cortisol found in Raynaud's syndrome in the absence of ANA may be responsible for the vasospasticity in this group of patients.     

Effects of Light and Elevated Atmospheric CO(2) on the Ribulose Bisphosphate Carboxylase Activity and Ribulose Bisphosphate Level of Soybean Leaves

Soybean (Glycine max L. Merr. cv Bragg) was grown throughout its life cycle at 330, 450, and 800 microliters CO₂ per liter in outdoor controlled-environment chambers under solar irradiance. Leaf ribulose-1,5-bisphosphate carboxylase (RuBPCase) activities and ribulose-1,5-bisphosphate (RuBP) levels were measured at selected times after planting. Growth under the high CO₂ levels reduced the extractable RuBPCase activity by up to 22%, but increased the daytime RuBP levels by up to 20%.

Diurnal measurements of RuBPCase (expressed in micromoles CO₂ per milligram chlorophyll per hour) showed that the enzyme values were low (230) when sampled before sunrise, even when activated in vitro with saturating HCO₃⁻ and Mg²⁺, but increased to 590 during the day as the solar quantum irradiance (photosynthetically active radiation or PAR, in micromoles per square meter per second) rose to 600. The nonactivated RuBPCase values, which averaged 20% lower than the corresponding HCO₃⁻ and Mg²⁺-activated values, increased in a similar manner with increasing solar PAR. The per cent RuBPCase activation (the ratio of nonactivated to maximum-activated values) increased from 40% before dawn to 80% during the day. Leaf RuBP levels (expressed in nanomoles per milligram chlorophyll) were close to zero before sunrise but increased to a maximum of 220 as the solar PAR rose beyond 1200. In a chamber kept dark throughout the morning, leaf RuBPCase activities and RuBP levels remained at the predawn values. Upon removal of the cover at noon, the HCO₃⁻ and Mg²⁺-activated RuBPCase values and the RuBP levels rose to 465 and 122, respectively, after only 5 minutes of leaf exposure to solar PAR at 1500.

These results indicate that, in soybean leaves, light may exert a regulatory effect on extractable RuBPCase in addition to the well-established activation by CO₂ and Mg²⁺.