Increased feeding after treatment with fructose, but not glucose, antimetabolites in rats with dopamine-depleting brain lesions

Rats were given dopamine-depleting lesions either as adults or as neonates. Compared with intact controls, lesioned rats failed to increase their food intake after acute administration of the glucoprivic agent, 2-deoxy-D-glucose. In contrast, both lesioned and control rats increased food intake after acute treatment with a peripherally-acting fructose antimetabolite, 2,5-anhydro-D-mannitol. These data suggest that the failure of lesioned rats to respond behaviorally to glucoprivation is related to inhibition of glycolysis in the brain, rather than the acute nature of the metabolic challenge.

Identification and partial characterization of an ectoATPase expressed by human natural killer cells

An extracellular membrane-associated ectoATPase has been identified on the human natural killer cell line NK3.3. The enzyme is distinct from other classes of ATPases, kinases, and phosphatases. NK3.3 ectoATPase demonstrated a Km for ATP of 41 microM and a Vmax of 0.2 mumol/min and required both Ca2+ and Mg2+ for maximal activity. Purine and pyrimidine nucleotides were competitive inhibitors of the catalytic reaction. Inhibition increased with the addition of increasing negative charge of the phosphate side chain and was also dependent on contributions from the nucleoside. NK3.3 ectoATPase activity was inhibited by reaction with the affinity label [p-(fluorosulfonyl)benzoyl]-5'-adenosine (5'-FSBA), which is shown to modify the enzyme at or near the ATP-binding domain. Photoaffinity labeling of intact NK3.3 cells with [alpha-32P]-8-azidoATP demonstrated an ATP-binding protein of 68-80 kDa unique to NK3.3 cells. A positive correlation was observed between the ability of the various nucleotides to block photoincorporation into the 68-80-kDa protein and their ability to inhibit ectoATPase activity. NK3.3 cells which were made ectoATPase-deficient by reaction with 5'-FSBA demonstrated that this enzyme does not have a major role in the protection of this cytolytic effector cell from the possible lytic effects of extracellular ATP.

Characterization of the Pseudomonas syringae pv. syringae 61 hrpJ and hrpI genes: homology of HrpI to a superfamily of proteins associated with protein translocation

The Pseudomonas syringae pv. syringae 61 hrpJ and hrpI genes were sequenced and found to encode predicted proteins of 37,710 Da and 76,490 Da, respectively. The products of these genes were confirmed by T7 polymerase-dependent expression and sodium dodecyl sulfate-polyacrylamide gel analysis. HrpI belongs to a superfamily of proteins represented by Yersinia pestis LcrD.

The esterified plasma fatty acid profile is altered in early HIV-1 infection

Previous studies have shown that alterations in micronutrient utilization occur in patients with Acquired Immune Deficiency Syndrome. In this study, total plasma fatty acid composition was measured in 36 homosexual men infected with the Human Immunodeficiency Virus 1 (HIV-1) and in 17 HIV-1 seronegative homosexual men in order to evaluate differences associated with early HIV-1 infection. Immunologic assessment included CD4 cell number count and lymphocyte blastogenesis in response to the mitogens phytohemagglutinin (PHA) and pokeweed (PWM). The mean total amount of omega 6 polyunsaturated fatty acids (18:2 and 20:4) was significantly lower in the HIV-1 seropositive subjects (38 +/- 8.1% SD) as compared to HIV-1 seronegative subjects (43 +/- 4.2%; P = 0.0027). This was also reflected in a higher level of total saturated fatty acids (16:0 and 18:0) in HIV-1 seropositive subjects (30 +/- 2.2% vs. 26 +/- 2.8%; P = 0.0001). The ratio of linoleic to arachidonic acid (18:2 to 20:4) was higher in the HIV-1 seropositive group (6.76 +/- 4.88) compared to the HIV-1 seronegative group (4.86 +/- 1.37; P = 0.0213). The response to PHA in seropositive subjects correlated inversely with total plasma omega 6 fatty acids (r = -0.36; P = 0.027), and directly with the 18:2 to 20:4 ratio (r = 0.33; P = 0.046). CD4 cell counts and the response to PWM did not correlate with plasma fatty acid levels in HIV-1 seropositive subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental study of pylorus and pyloric vagus preserving gastrectomy

In an attempt to prevent the sequelae of conventional gastrectomy, such as rapid gastric emptying, dumping syndrome, intestinal content reflux, indigestion, and poor absorption, we have devised the pylorus and pyloric vagus preserving gastrectomy (PPVPG). Experimenting on 48 dogs, we found theoretic grounds for using our design and obtained the desired effects--retaining the merits of conventional subtotal resection of the stomach, with acidity reduction, while avoiding the above-mentioned complications.

Cardiac conduction system in the chicken: gross anatomy plus light and electron microscopy

Twenty-three chicken hearts were used to study the cardiac conduction system by light and electron microscopy. In addition to a sinus node, atrioventricular node (AVN), His bundle, left and right bundle branches (LBB, RBB), the chicken also has an AV Purkinje ring and a special middle bundle branch (MBB). The sinus node lies near the base of the lower portion of the right sinoatrial valve. The AV node is just above the tricuspid valve and anterior to the coronary sinus. The His bundle descends from the anterior and inferior margin of the AV node into the interventricular septum, then dividing into right, left and middle branches some distance below the septal crest. The middle bundle branch turns posteriorly toward the root of the aorta. The AV Purkinje ring originates from the proximal AV node and then encircles the right AV orifice, joining the MBB to form a figure-of-eight loop. The chicken conduction system contains four types of myocytes: 1) The P cell is small and rounded, with a relatively large nucleus and sparse myofibrils. 2) The transitional cell is slender and full of myofibrils. 3) The Purkinje-like cell resembles the typical Purkinje cell, but is smaller and darker. 4) The Purkinje cell is found in the His bundle, its branches, and the periarterial and subendocardial Purkinje network.

Cloning and expression of a novel human DNA binding protein, PO-GA

We have cloned a novel human DNA-binding protein from a HeLa cDNA expression library using the cognate DNA binding site of a transcription factor, PO-B. Further hybridization screening with the initial clone produced contiguous cDNA sequence of 4508 bp and a complete open reading frame encoding a 128 kDa protein, PO-GA. Northern analysis revealed a wide distribution of PO-GA mRNA in most human tissue. However, PO-GA mRNA levels were lower in lung and kidney and undetectable in placental tissue. A DNA-binding fragment of PO-GA expressed in E. Coli bound selectively to the PO-B element and other GA-rich double-stranded DNA sequences and to certain single-stranded DNA sequences. PO-GA has regions of homology to E. coli and yeast DNA ligases, and to proteins involved in DNA repair. Thus, in addition to a potential role in transcription, PO-GA may also be involved in DNA repair or replication.

Induction of N-acetylglucosaminyltransferase V by elevated expression of activated or proto-Ha-ras oncogenes

Viral infection of cultured cells with transforming viruses causes an increase in cell-surface N-linked beta 1-6 (GlcNAc beta 1-6Man) branching of complex-type oligosaccharides. Similar observations have been made after transfection of cells with activated oncogenes, which is associated with an induction of tumorigenic and metastatic properties. In this study, the effects of transfection of both activated and proto-Ha-ras oncogenes into NIH3T3 cells were analyzed. The results showed that, in comparison with NIH3T3 cells, both ras transfectants have increased sensitivity to the cytotoxic action of L-PHA. An increase in beta 1-6 branching and an increased level of N-acetylglucosaminyltransferase V (GlcNAc-T V), the enzyme which initiates the beta 1-6 branching were also observed. The levels of GlcNAc-T I and beta 1-4 Gal-T remained unchanged in activated Ha-ras transfected NIH3T3 cells. These data suggest that a specific induction of GlcNAc-T V occurs after transfection with either the proto- or activated Ha-ras oncogenes, which is responsible for the increased beta 1-6 branching previously observed.

[X-ray computed tomography in the diagnosis of peritoneal and retroperitoneal neoplasms]

CT findings of peritoneal and retroperitoneal neoplasms were evaluated in 24 patients. The accuracy of CT in locating peritoneal and retroperitoneal tumors was 87% and in differentiating benign from malignant ones 96%. It is difficult to evaluate the tumors histopathologically. We suggest that CT scan be preferable in diagnosis of tumors in that area.

[A rapid assaying method for biotin determination and the computer program for data calculation]

A rapid auxanographic method for biotin determination was established by means of a biotin auxotrophic yeast strain, and a computer program was designed to calculate the data obtained. Its determination concentration ranges from 0.3 to 5.0 micrograms/ml. The time-tested routine work in our laboratory proved that it is rapid, precis and reliable.

The NF-kappa B p65 promoter

The promoter of the human gene encoding the p65 subunit of the transcription factor NF-kappa B was cloned and the nucleotide sequence determined. The p65 promoter lacks both TATA and CCAAT consensus sequences. The p65 promoter contains three consensus binding sites of the transcription factor SP1. In contrast to the promoter of the p50 subunit of NF-kappa B, no sequences predicted to bind NF-kappa B are present in the p65 promoter. Phorbol ester (PMA) and phytohemagglutinin (PHA) treatment of Jurkat cells did not activate the p65 promoter in transient transfection experiments. Using different deletion mutants of the p65 promoter, essential promoter elements were mapped.

Isolation of oligomannose-type glycans from bean glycoproteins

We have isolated individual oligosaccharyl-asparagine derivatives from the total soluble glycoproteins from kidney beens (Phaseolus vulgaris) and from lima beans (Phaseolus limensis). The protein/glycoprotein mixture was digested exhaustively by pronase, and the glycan-containing fractions were separated from free amino acids and peptides by gel filtration. The oligosaccharyl-asparagine derivatives were finally fractionated on Dowex 50 (C. C. Huang, H.E. Meyer, and R. Montgomery, Carbohydr. Res. 13, 127-137, 1970), and the individual fractions were characterized by mass spectrometry, NMR, and ion exchange chromatography. With the procedures described, only oligomannose derivatives were obtained from the beans. In the case of kidney beans, six different derivatives were observed and characterized, Man9GlcNAc2Asn, two positional isomers of Man8GlcNAc2Asn, two positional isomers of Man7GlcNAc2Asn, and Man6GlcNAc2Asn. Under identical conditions the lima beans yielded primarily the Man9GlcNAc2Asn derivative along with a small amount of the two Man8GlcNAc2Asn derivatives. The oligomannose structures can be isolated in reasonable quantities (2-20 mg) from about 200 g of dry beans.

Point mutations are associated with a gene duplication leading to the bloodstream reexpression of a trypanosome metacyclic VSG

African trypanosomes evade the immune response of their hosts by sequentially expressing different variant surface glycoproteins (VSGs). We isolated a bloodstream trypanosome clone of Trypanosoma brucei rhodesiense that expresses a VSG normally present during the metacyclic stage of the parasite in the insect vector. Associated with the bloodstream reexpression of this metacyclic VSG is a gene conversion in which the duplicated, expressed gene of 1650 nt contains 11 scattered point mutations when compared with its donor gene. Analysis of an uncloned population of bloodstream trypanosomes revealed another VSG reexpressor of the same donor gene in which the coding region had undergone 24 point mutations. The mutations are unique to the duplicated gene and appear to be nontemplated. The generation of these mutations provides a way for the trypanosome to increase further its antigenic diversity.

Expression of chimeric human transferrin-chloramphenicol acetyltransferase genes in liver and brain of transgenic mice during development

Transferrin (TF) gene expression is tissue specific and is regulated during development. Transgenic mice have been developed which carry 1.2 or 0.67 kb of the TF 5' flanking region of the human TF gene fused to the bacterial chloramphenicol acetyltransferase (CAT) gene. The onset of expression of the chimeric human TF-CAT transgenes in liver and brain during development has been studied in these transgenic mice. In brain, the TF(0.67)CAT transgene began to express between 5 and 10 days after birth; in liver, the TF(0.67)CAT transgene was turned on between 10 and 20 days after birth. Endogenous mouse TF mRNA levels in liver and brain have also been measured during development by Northern analysis. In brain, the developmental expression pattern of the TF(0.67)CAT transgene is the same as the mouse endogenous TF gene; in liver, the transgene is turned on later than the endogenous mouse TF gene. DNA-protein mobility shift assays and DNase I footprinting analyses were conducted in the region of -621 to -409 bp of the human TF gene by using TF-CAT expressing liver nuclear extract from 27-day-old mice and nonexpressing liver nuclear extract from 7-day-old mice. The level of protein-DNA complex formation is several times higher in the expressing extracts, and the region from -481 to -463 bp of human TF gene is protected by the expressing extract but not the nonexpressing extracts. As demonstrated by this and other studies, the transgenic mouse model furnishes a unique opportunity to analyze developmental regulation of human transgenes.

On the regulation of K+ uniport in intact mitochondria by adenine nucleotides and nucleotide analogs

Respiring mitochondria drive the electrophoretic uptake of K+ and other cations. In the presence of permeant acids this transport leads to mitochondrial swelling if it is not compensated by electroneutral K+/H+ exchange mediated by the K+/H+ antiporter. The mechanism of influx has yet to be established; however, evidence is accumulating that in addition to leak pathways a specific K+ channel or uniporter may be involved. We examine some of the properties of K+ uniport which are consistent with the existence of a specific ATP-regulated K+ channel. In contrast to the K+/H+ antiporter, K+ uniport shows little dependence on pH. K+ uniport is, however, very sensitive to inhibition by adenine nucleotides. The maximum percent inhibition is increased from 40 to 60% by treatment of mitochondria with N-ethylmaleimide (30 nmol/mg) which stimulates K+ uniport 3.6-fold. N-Ethylmaleimide, however, has no effect on the IC50 values which are 0.5, 2.3, and 8 microM for ADP, ATP, and AMP, respectively. GDP has no effect, while carboxyatractyloside is found to inhibit. The nucleotide analogs Cibacron blue 3GA and erythrosin B exhibit three effects on K+ uniport. Low doses partially inhibit K uniport (I50 = 0.13 microM Cibacron Blue), while higher doses stimulate (EC50 = 13 microM Cibacron Blue). Stimulation is especially apparent in N-ethylmaleimide-treated mitochondria. These analogs also antagonize inhibition by ATP. Since the EC50 values for this antagonism for these two drugs are similar, while the IC50 values for inhibition of ATP transport differ by a factor of five, we suggest that inhibition of K+ uniport by ATP is not mediated via the adenine nucleotide translocase. These data are consistent with the existence of an ATP-regulated K+ channel in the inner mitochondrial membrane.

Measured properties of doubly rotated dilithium tetraborate (Li(2)B(4)BO(7)) resonators and transducers

Dilithium tetraborate plates, cut to the nominal angles of cut of (YXwl)40 degrees /33 degrees (TA-cut) and (YXwl)19 degrees /56 degrees (TC-cut), have been supplied by a crystal grower and have been processed into plate resonators. The mode spectra and electrical circuit parameters of the resonators have been examined for the fundamental, third, and fifth harmonics for all three thickness modes of the resonators. The observed values of frequency constants and piezoelectric coupling are in good agreement with the predicted values. The frequency-temperature behavior of the zero-temperature coefficient cuts has also been measured.

Molecular aspects of early stages of breast cancer progression

It is clear that breast cancer progression is associated with inactivation of a number of different recessive oncogenes. The most widely evaluated tumor suppressor gene, p53, is mutated in approximately 30-50% of sporadic breast cancers. Mutations usually occur early in malignant progression. Loss of heterozygosity (LOH) studies have identified numerous chromosomal regions where other recessive oncogenes relevant to breast cancer may be located. Each LOH is seen in a varying proportion of breast cancers and may appear either early or late in progression. High-grade ductal carcinoma in situ (DCIS) and invasive carcinoma have similar genetic lesions, showing that aberrations can occur before invasive disease. Direct evidence that the same aberrations can be acquired later in progression comes from a study of multiple metastases from the same patient; other studies found that primary invasive cancers are characterized by marked intratumor heterogeneity for each lesion examined. The model we propose to account for these results hypothesizes that multiple genetic lesions can accomplish each phenotype required for malignancy (i.e., dysregulated proliferation, invasion, angiogenesis, etc.) and that, for a given tumor, at least one aberrant gene for each phenotypic change is stochastically selected. Biological heterogeneity of breast cancer results from the stochastic acquisition of various genetic aberrations. We further propose that the lymphocytic reaction in high-grade DCIS may select for aggressive tumor subpopulations capable of escaping immune surveillance. Another aspect of tumor heterogeneity may be the multiple mechanisms employed by various tumors to escape immune surveillance.

Hypocapnia worsens arterial blood oxygenation and increases VA/Q heterogeneity in canine pulmonary edema

BACKGROUND

Hyperventilation frequently is employed to reduce carbon dioxide partial pressure in patients in the operating room and intensive care unit. However the effect of hypocapnia on oxygenation is complex and may result in worsening in patients with preexisting intrapulmonary shunt. To better define the interplay between hypocapnia and oxygenation, the effects of hypocapnia and hypercapnia on the matching of ventilation (VA) and perfusion (Q) were studied in dogs with oleic acid-induced pulmonary edema, using the multiple inert gas elimination technique.

METHODS

Eight pentobarbital-anesthetized, closed-chested dogs were administered 0.06 ml/kg of oleic acid at least 150 min prior to study. Ventilation was set with an FIO2 of 0.90, a tidal volume of 20 ml/kg, and a respiratory rate of 35 breaths/min. The arterial carbon dioxide tension (PaCO2) was varied in a randomized order to three levels (26, 38, and 50 mmHg) by altering the amount of CO2 in the inspired gas mixture. Gas exchange was assessed by true shunt, dead space, the log standard deviation of the perfusion (log SDQ) and the ventilation (log SDV) distributions, and the tracer inert gas arterial-alveolar difference ([a-A]D) area.

RESULTS

Cardiac output (4.1 +/- 0.4 L/min), mean pulmonary artery pressure (25 +/- 1 mmHg), inert gas shunt (22 +/- 3%), and dead space (38 +/- 4%) during normocapnia were not different from that during hypocapnia and hypercapnia. Hypocapnia increased (P < .05) the alveolar-arterial oxygen tension difference (P[A-a]O2) and decreased (P < .05) the arterial blood oxygen tension (PaO2, 181 +/- 33 mmHg vs. 221 +/- 35 mmHg with normocapnia). P[A-a]O2 and PaO2 were unaffected by hypercapnia. During hypocapnia, VA/Q inequality increased, demonstrated by an increase (P < .05) in log SDQ (1.60 +/- 0.15 vs. 1.35 +/- 0.19 with normocapnia) and in the [a-A]D area (0.63 +/- 0.09 vs. 0.50 +/- 0.09 with normocapnia) indexes of VA/Q heterogeneity. During hypercapnia, the [a-A]D area (0.63 +/- 0.11) and log SDV (1.13 +/- 0.10 compared to 0.97 +/- 0.12 with normocapnia) also were increased (P < .05). With hypocapnia, there was a small but insignificant increase in blood flow to shunt and low VA/Q areas (29 +/- 4% compared to 26 +/- 4% with normocapnia). In the presence of a high FIO2, this small increase in shunt and low VA/Q may result in a significant decrease in PaO2.

CONCLUSIONS

Both hypocapnia and hypercapnia were associated with an increased VA/Q inequality. However, PaO2 decreased and P[A-a]O2 increased with only hypocapnia. These results suggest that hyperventilation to reduce PaCO2 may be detrimental to arterial PO2 in some patients with lung disease.