Effect of denervation of carotid labyrinths on breathing in unrestrained Xenopus laevis

The effect of denervation of the carotid labyrinths on breathing responses to simultaneously applied aerial and aquatic normoxia, hypoxia, or hypercapnia has been studied in unrestrained Xenopus laevis. Denervation significantly reduced VI of normoxic toads compared with VI in intact and sham-operated toads, due to a significant reduction in the volume of each buccal pumping movement (VB) in denervates. Breathing increased significantly in response to environmental hypoxia or hypercapnia in intact and sham-operated toads as well as in denervates. Breathing frequency (fRESP) was the major determinant of the increase in VI for VB was unchanged and even fell slightly in denervates in hypercapnia. Dive time (DT) was significantly reduced in both hypoxia and hypercapnia, from that in normoxia. DT fell significantly more in hypoxia than in hypercapnia in both denervates and intact and sham-operated toads. It is concluded that the carotid labyrinth does not play a major role in regulating breathing in hypoxia or hypercapnia in unrestrained Xenopus.

Characterization of the polypeptide composition of human factor VIII:C and the nucleotide sequence and expression of the human kidney cDNA

Human coagulation factor VIII:C has been purified approximately 5000-fold from commercial preparations with an average activity yield of 35%. Proteins of 92 kD and 77-80 kD enriched during purification are precipitated by a human serum polyclonal antibody which inhibits factor VIII:C activity. Evidence suggests that these polypeptides are linked by a calcium ion bridge. Partial amino acid sequence information from these proteins has been obtained from the intact polypeptides and from products of digestion with thrombin, endoproteinase lysC, or trypsin after citraconylation. An oligonucleotide probe designed from one of the amino acid sequences was used to isolate a partial genomic clone from a human 4X chromosome library in bacteriophage lambda. The genomic segment was used to isolate two cDNA molecules encompassing the entire human kidney factor VIII:C mRNA. Biologically active factor VIII:C has been produced in a mammalian cell line utilizing a complete cDNA construction.

Serum antibody responses of juvenile and infant rhesus monkeys injected with Haemophilus influenzae type b and pneumococcus type 6A capsular polysaccharide-protein conjugates

Juvenile and infant rhesus monkeys were injected subcutaneously with saline solutions of Haemophilus influenzae type b (Hib) and pneumococcus type 6A (Pn6A) capsular polysaccharides conjugated to either tetanus toxoid (TT), horseshoe crab hemocyanin, or cholera toxin (CT), and the antibody responses of the monkeys to both bacterial components were measured. All three Hib conjugates were immunogenic and elicited booster responses; their comparative immunogenicity was Hib-CT greater than Hib-TT greater than Hib-horseshoe crab hemocyanin. Hib alone did not elicit antibodies in the juveniles. Juveniles responded earlier and with higher levels of antibodies than did infants. TT, as well as diphtheria-tetanus toxoids-pertussis vaccine adsorbed injected concurrently at a separate site, increased both Hib and TT antibody responses in juveniles (P less than 0.05). Concurrent injection of 5 Lf of fluid TT with a nonimmunogenic 5-micrograms dose in infants elicited levels of Hib antibodies comparable to those elicited by 50 micrograms of Hib-TT. Hib antibodies elicited by the conjugates remained at protective levels in both juveniles and infants 2 months after the last injection, were bactericidal, and conferred passive immunity against bacteremia in infant rats. Passive immunization of juveniles with tetanus immune globulin before each injection of Hib-TT did not suppress Hib antibodies. Hib-TT and Hib-CT elicited increases of Hib antibodies of the immunoglobulin M and G isotypes in the infants. The Pn6A-TT conjugate was considerably less immunogenic than the Hib-TT conjugate; only a few of the juveniles or infants responded with protective levels of Pn6A antibodies. Pn6A antibodies from responders conferred protection in mice against intraperitoneal challenge with Pn6A organisms. TT antibodies were elicited in both juvenile and infant animals after one injection of 50 micrograms of Hib-TT and in the infants injected with 5 micrograms of Hib-TT plus 5 Lf of TT; 5 micrograms of Hib-TT and Pn6A-TT in combination alone did not elicit TT antibodies. Hib-CT elicited CT antibodies in both juveniles and infants.

A comparison of high-energy accelerator depth dose data

Accurate depth dose information is necessary for the use of high-energy radiotherapy photon beam units. It would be useful, therefore, to have one set of published data available for each different type unit manufactured to which physicists can compare their measured data. Pertinent questions are raised regarding the similarity between accelerators and their central axis depth dose characteristics, the availability of adequate published central axis depth dose data, and the minimum amount of data needed to determine the applicability of published data to a particular machine. Data taken by the Radiological Physics Center (RPC) for 4-10 MV units are analyzed and compared with published data in an attempt to answer these questions.

Further studies on the immunogenicity of Haemophilus influenzae type b and pneumococcal type 6A polysaccharide-protein conjugates

Conjugates were prepared by carbodiimide-mediated coupling of adipic acid hydrazide derivatives of Haemophilus influenzae type b (Hib), Escherichia coli K100, and pneumococcal 6A (Pn6A) polysaccharides with tetanus toxoid (TT), as an example of a "useful" carrier, and horseshoe crab hemocyanin (HCH), as an example of a "nonsense" carrier. These conjugates were injected into NIH mice, and their serum antibody responses to the polysaccharides and proteins were characterized. As originally reported, Hib conjugates increased the immunogenicity of the capsular polysaccharide and elicited greater than the estimated protective levels of anti-Hib antibodies in most recipients after one injection and in all after the third injection (Schneerson et al., J. Exp. Med. 152:361-376, 1980). Both Hib conjugates induced similar anti-Hib responses. The K100-HCH conjugate was more immunogenic than the K100-TT conjugate and elicited anti-Hib responses similar to the Hib conjugates after the third injection. Simultaneous injection of the K100 and the Hib conjugates did not enhance the anti-Hib response. The Pn6A-TT conjugate induced low levels of anti-Hib antibodies; when injected simultaneously with the Hib conjugates, the anti-Hib response was enhanced, as all mice responded after the first injection and with higher levels of anti-Hib than observed with the Hib conjugates alone (P < 0.05). The Pn6A conjugates were not as immunogenic as the Hib conjugates. Pn6A-TT was more effective than was Pn6A-HCH; it elicited anti-Pn6A (>100 ng of antibody nitrogen per ml) in 6 of 10 mice after the third injection. The addition of the Hib-HCH conjugate to the Pn6A-TT conjugate increased the anti-Pn6A response with a higher geometric mean antibody titer, and 9 of 10 mice responded after the third injection. A preparation of diphtheria toxoid, TT, and pertussis vaccine increased the anti-Hib antibody levels after the first injection only in mice receiving Hib-TT, but not in mice receiving Hib-HCH, suggesting that additional carrier protein (TT) enhanced the anti-polysaccharide response. Simultaneous injection of Hib and Pn6A conjugates with the same or different carriers resulted in an enhanced serum antibody response to each polysaccharide. The anti-tetanus toxin response reached protective levels (>0.01 U/ml) in most mice after the first injection and in all mice after the second and third injections of TT conjugates. A progressive increase in the anti-HCH response with each additional injection was noted in animals receiving HCH conjugates. Animals receiving the diphtheria toxoid-TT-pertussis vaccine preparation responded with a greater increase in anti-carrier antibody than those receiving the conjugates alone. This method of synthesis provided conjugates capable of inducing protective levels of antibodies to both the polysaccharides and carrier proteins.

Chemical cocarcinogenesis with the use of a subclone derived from Balb/3T3 cells with catechol as cocarcinogen

This study was performed for the detection of cocarcinogens by transformation in vitro with the use of a subclone of a Balb/3T3 cell line. Dose response, cytotoxicity, and transformation studies were done with the use of an indirect-acting carcinogen, benzo[a]pyrene (B[a]P), a direct-acting alkylating carcinogen, beta-propiolactone (BPL), and the mouse skin cocarcinogen catechol. The rate of transformation was notably higher in groups treated with B[a]P and catechol or BPL and catechol than in groups treated with either B[a]P or BPL. Catechol alone did not induce any transformation. All the cells isolated from the transformed foci showed characteristics of malignantly transformed cells, such as anchorage-independent growth. Thus chemical cocarcinogenesis was accomplished in vitro similar to that accomplished in in vivo studies reported earlier on mouse skin.

Metabolic fate of nitrosoproline in the rat

The metabolism of [U14C]nitrosoproline and [carboxyl-14C]-nitrosoproline was studied in the rat. In most experiments, less than 1% of the administered radioactivity appeared as radioactive CO2 in the expired air, and urinary excretion of radioactivity was rapid and almost complete as the unchanged compound, which was the only radioactive component detected in the urine. The absence of any radioactive urinary components corresponding to proline or its metabolites indicated that no detectable metabolic denitrosation had occurred. Studies of the disappearance of nitrosoproline from the circulating plasma indicated an apparent volume of distribution of 52% of the total body weight, suggesting some penetration by the compound into the intracellular space. There was no significantly detectable covalent binding of radioactivity from the labeled nitrosoproline to DNA ro RNA of the liver and only an extremely low level of binding to liver protein. Taken with the reported noncarcinogenicity of nitrosoproline in rodents, the above findings suggest that proline may be a suitable nitrosatable substrate for use in tests of endogenous nitrosation reactions in animals and human subjects.

Distribution along the rat nephron of three enzymes of gluconeogenesis in acidosis and starvation

Methods were devised or modified which made it possible to measure phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase in seven defined parts of single nephrons and in patches from thin limb and papilla areas dissected from freeze-dried microtome sections of rat kidney. All three enzymes were essentially confined to the proximal tubule. In normal kidneys, the levels were highest in the proximal convoluted tubule. Glucose-6-phosphatase was 20 times higher in the early part of the convoluted segment than in the late part of the straight segment. With one exception, in acidosis, only phosphoenolpyruvate carboxykinase increased (fourfold in the proximal convoluted segment but much less in the straight portion). In starvation, phosphoenolpyruvate carboxykinase increased about as much as in acidosis in the proximal straight tubule, but not as much in convoluted portions, whereas glucose-6-phosphatase rose modestly in both parts of the proximal tubule and fructose bisphosphatase rose only in the straight tubule, especially the early segment. It is suggested that ammoniagenesis can accompany gluconeogenesis in the proximal convoluted tubule but not in the straight segment.

Gluconeogenic enzymes in defined structures of developing rat nephron

Three gluconeogenic enzymes, P-pyruvate carboxykinase (PPCK), fructose-1-6 bisphosphatase (FBPase), and glucose-6-phosphatase (G6Pase) were measured in identified structures of rat nephron from 2 days before birth to maturity. In the proximal convoluted tubule, the three enzymes increased from the earliest age assayed to +14 days (PPCK, 7-fold, FBPase, 2-fold and G6Pase, 50-fold). Among the 7 defined structures that were analyzed, highest levels at all ages were in the proximal convoluted tubule with almost no activity in the distal convoluted tubule. All three enzymes had negligible activity in the neogenic zone and mesenchyme. Supported by grants from the Public Health Service (HD 03891 and NS-05221) and the American Cancer Society (P-78).

Effects of nine N-nitroso compounds on the specific radioactivity of liver proteins after injection of [14C]leucine into rats

We compared the effect of nine N-nitroso compounds, given by gavage to adult rats, on specific radioactivity of the trichloroacetic acid-precipitable liver proteins, 1 hr after the injection of [14C]leucine. The specific radioactivity was decreased by dimethylnitrosamine, diethylnitrosamine, methyl-n-butylnitrosamine, and nitrosomorpholine 5 to 10 hr after their administration; was increased by nitrosopiperidine, dinitrosopiperazine, and methylnitrosourea 5 to 24 hr after gavage; and was unaffected by nitrososarcosine and nitrosodihydrouracil. With dimethylnitrosamine, specific radioactivity was decreased by 10 but not 5 mg/kg. In control rats and rats given injections of either of two nitrosamines, protein specific radioactivity at 60 min after the [14C]leucine injection was 76 to 87% of that at 30 min, indicating some degradation of the proteins at 60 min. The liver:blood ratio of [14C]cycloleucine concentration was unaffected by four nitrosamines, indicating no effect on leucine transport. The effect of the nine compounds was examined on total pool size of free leucine in the liver, at times close to those for the maximum specific radioactivity effect. For these data, we calculated "corrected specific radioactivity," adjusted for changes in pool size. This adjustment is only a first approximation since, for example, the free leucine pool is not uniform with respect to protein synthesis. The four N-nitroso compounds that decreased specific radioactivity also decreased corrected specific radioactivity, even though they enlarged the leucine pool. Of the remaining compounds, two enlarged the leucine pool and three increased corrected specific radioactivity. For all nine compounds, the decrease in specific and correlated with the ability to cause acute liver necrosis. When nitrosodihydrouracil was excluded, the decrease in specific and corrected specific radioactivity was significantly correlated with the reported liver carcinogenicity.

A Study of Fireflood Field Projects (includes associated paper 6504)

More than 40 domestic and foreign firefloods were reviewed. Regressionequations were developed for predicting production performanceof firefloods. Two screening guides were established for selecting reservoirs for the application of the fireflood process.

Introduction

Enhanced recovery methods that show most promise forcommercial application include hydrocarbon miscibleflood, carbon dioxide miscible flood, micellar flood, andthermal recovery methods. Since the first threeprocesses are applicable only to low-viscosity crudes (10 cpor less), the recovery of medium- to high-viscosity crudesdepends solely on thermal methods - steam stimulation, steamflood, and fireflood.

A recent domestic survey showed that, of the threethermal methods, steam stimulation has been practicedexclusively in California and steamflood has been usedpredominantly there. Fireflood projects, on the otherhand, cover a much wider area including California, Texas, Louisiana, Oklahoma, Arkansas, Illinois, Mississippi, Nebraska, and Wyoming. This wide geographical distribution of fields amenable to firefloods clearlyindicates that firefloods are applicable to a broader range ofreservoir and crude properties than steam stimulation andsteamflood.

More than 70 firefloods have been completed or are inprogress in the U.S. Firefloods also have been practicedin other countries such as Venezuela, U.S.S.R., Romania, and Japan. Varying information is available onmore than 40 domestic and foreign firefloods.The purpose of this paper is to review these firefloods and therebydevelop criteria for screening prospects for theapplication of the fireflood process.

This paper first gives a general description of firefloodand its variations and discusses variables characterizingthe performance of firefloods. Screening guides forfireflood prospects are developed by two different statisticalapproaches - the confidence-limits approach and theregression-analysis approach. The choice betweenfireflood and steamflood is also discussed.

Fireflood and Its Variations

The most commonly used form of the fireflood process isdry forward combustion. The process is called drycombustion because no water is injected along with air.The combustion is forward because ignition occurs near the injection well and the burning front moves forward fromthe injection well to the production well. The advantageof this process is that an undesirable fraction of the crudeis burned in the form of coke, leaving clean sand in theregion behind the burning front. However, it has twolimitations. First, the produced oil has to pass through acold region of the reservoir. If the oil is highly viscous, liquid blocking will occur, which may terminate theprocess. Second, heat stored in the burned-out region isnot utilized efficiently because injected air is notsufficiently effective to carry the heat forward.

Reverse combustion is a variation of the fireflood thatremedies the first limitation of the conventional fireflood.Ignition occurs near the production well and the burningfront moves countercurrent to the flow of the injected air.Since oil moves through a hot region toward the produced well, there is no upper limit to the viscosity of thereservoir crude. Reverse combustion is not as efficient asforward combustion because a desirable fraction of theoil is burned as the fuel, and the undesirable fraction remains in the region behind the combustion front.

JPT

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