[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.

Management of major arterial injuries of the limbs in 166 cases

The charts of 166 patients with major arterial injuries (175 arterial repairs) inflicted during periods of peace and war time were reviewed. One hundred and sixty-seven (95%) of the arteries repaired remained patent. Nine patients had limbs which developed ischemic contracture. Nine patients required amputations. Follow-up data was obtained from seventy-five patients with an average follow-up of five years and one month (six months to thirty years). Early diagnosis, prompt treatment including fasciotomies when indicated, complete debridement, appropriate coverage, meticulous surgical technique, and simultaneous treatment of concomitant injuries are all crucial factors in successful limb salvage. Major arterial injuries of the limb occur frequently in our patient population, especially in time of war. Successful treatment of major arterial injuries may be life-saving, as well as allowing limb salvage and restoration of limb function. The purpose of this study is to review our experience with repair of major arterial injuries.

Pure-mode loci in piezoelectric plate resonators: application to materials evaluation in class 4 mm

The accuracy of piezoelectric material evaluations can be enhanced by the use of pure-mode orientations, provided that exact analytic expressions for the pure-mode eigenvalues are known. The accuracy is enhanced by eliminating the need to extract constants from the differences in sums and products of measured quantities. It is necessary to adopt an approach for determining pure-mode loci in piezoelectric crystals which yields simple analytic expressions for the stiffness eigenvalues and provides a convenient engineering methodology for pure-mode sample set selection. The theory of simple thickness modes in piezoelectric plate vibrators is reviewed. The determination of pure-mode loci and its application to pure-mode sample set selection for dilithium tetraborate are presented. Thickness- and lateral-field excitation considerations are discussed.

Histological organization of the right and left atrioventricular valves of the chicken heart and their relationship to the atrioventricular Purkinje ring and the middle bundle branch

In the avian heart the right and left atrioventricular (AV) valves not only exhibit their own special anatomical characteristics, but they also are in close proximity to the conduction system. The right AV valve is a single, spiral plane of myocardium, in remarkable contrast to the fibrous structure characteristic of the mammalian tricuspid valve. A ring of Purkinje tissue encircles the avian right AV orifice and connects to the muscular valve. The chicken has no crista supraventricularis, its right AV valve serving that function as well as opening and closing the right AV orifice. The left AV valve consists of three leaflets instead of the two typical of mammalian hearts. Its anterior and posterior leaflets are small; its large aortic (medial) leaflet merges with the bases of both the left and noncoronary cusps of the aortic valve by fibrous tissue, resembling that of the mammalian heart. However, unlike in mammals, there is a slim cylinder of continuous myocardium coursing parallel to this fibrous junction. This unusual arc of myocardium in the chicken serves to complete an entire subaortic ring of myocardium and is thus potentially capable of constricting the outflow tract of the chicken's left ventricle. The middle bundle branch connects with both the muscle arch and the AV Purkinje ring. Thus the myocardium in or near both AV valves (and the left ventricular outflow tract) in the chicken heart is so arranged that it may receive direct early activation from the conduction system.

Cloning and nucleotide sequence of human liver cDNA encoding for cystathionine gamma-lyase

We have cloned and sequenced a full-length cDNA (1083 bp) encoding the human liver cystathionine-gamma-lyase enzyme (cystathionase). The human cystathionase sequence presented a substantial deletion of 132 bases (44 amino acids) compared to that reported for rat cystathionase, and of 135 bases (45 amino acids) compared to that reported for yeast cystathionase. After re-alignment for the missing nucleotides, the human cDNA sequence shows significant amino acid homology to that for the rat enzyme (85%) and the yeast enzyme (50%). A search for an undeleted cDNA, by the polymerase chain reaction, yielded a second clone which contained the missing 132 bases. Flanking nucleotides in the latter clone were identical to those in the cDNA clone containing the deletion. The two forms of human cystathionase deduced from the two cDNA clones may be derived from two different genes or may be splice variants.

AraC protein contacts asymmetric sites in the Escherichia coli araFGH promoter

AraC protein regulates the transcription of arabinose transport and catabolic operons in Escherichia coli through interaction with specific DNA sequences in the promoter regions of the operons. The interaction of AraC protein with two binding sites in the araFGH promoter was determined and compared to previously studied AraC binding sites in the araBAD promoter. Methylation and ethylation interference assays show that AraC protein binds along one side of the DNA to four adjacent major groove regions at each of the araFG1 and araFG2 sites. Mutations within any of the four regions of araFG1 greatly reduce protein binding in vitro. The promoter function in vivo is also greatly reduced, indicating that all four regions of the binding site are required. The chemical interference and genetic data, combined with the consensus sequence for AraC protein binding to ara promoters, support a binding motif in which two directly repeated units each span two adjacent turns of the DNA helix. The function of the two AraC binding sites was also examined. The proximal araFG1 site is required for promoter activation, whereas the distal araFG2 site has only a slight effect on the promoter activity.

Microdetermination of G6PD isoenzyme activity in human erythrocytes by thin-layer PAG-IEF

An improved method of microdetermination of G6PD isoenzyme activity in human erythrocytes was developed by modification of previously reported procedures. The volume of blood samples was reduced from 2 ml to 20 microliters. After hemolysis in 2% Triton X-100 and 0.1% beta-mercaptoethanol, the samples were subjected to centrifugation and thin-layer isoelectric focusing in polyacrylamide gel (PAG-IEF). By comparison with the original method, excellent resolution was obtained by this more rapid and simple procedure.

A comparison of the mouse versus human aryl hydrocarbon (Ah) receptor complex: effects of proteolysis

The differences in the molecular properties of the nuclear aryl hydrocarbon (Ah) receptor from human Hep G2 and mouse Hepa 1c1c7 cells were investigated by time-dependent partial proteolysis with chymotrypsin or trypsin followed by column chromatographic and velocity sedimentation analysis. The sedimentation coefficients, Stokes radii and apparent molecular weights of the untreated human and mouse Ah receptor complexes were similar. Treatment of the nuclear Ah receptor complexes from both cell lines with chymotrypsin for 10 or 60 min gave lower molecular weight proteolytic products which also exhibited comparable molecular properties and salt gradient elution profiles from Sepharose columns linked to DNA. Treatment of the human and mouse nuclear Ah receptor complexes with trypsin (5 micrograms/mg protein) for 10 or 60 min gave a minor low molecular weight (29.7- or 25.7-kDa) proteolysis product which was detected only with the mouse Hepa 1c1c7 Ah receptor complex. The time- and concentration-dependent proteolytic digest maps of the human and mouse Ah receptor were determined using receptor preparations which were photoaffinity labeled with [125I]7-iodo-2, 3-dibromodibenzo-p-dioxin. The human Ah receptor was significantly more resistant to proteolysis by trypsin or chymotrypsin than the mouse Ah receptor. At a low concentration of chymotrypsin (1 microgram/mg protein) the Hepa 1c1c7 receptor was degraded to two lower molecular weight fragments with apparent M(r) values at 71- and 48-kDa whereas the Hep G2 Ah receptor was relatively stable under these conditions. Although the human Ah receptor was more slowly hydrolyzed than the mouse receptor by trypsin, the major photolabeled breakdown products for the Ah receptor from both cell lines were observed at M(r) 48- and 45-kDa. The results of this study demonstrate that there were subtle but significant differences in the human and mouse Ah receptor complex; however, the proteolysis studies suggest that there are common structural features in their ligand binding sites.

Dielectric properties of human glioma and surrounding tissue

Dielectric properties of human glioma and surrounding tissue from five patients were measured. Experiments were performed at frequencies of 5-500 MHz at 24 +/- 0.5 degrees C using a Network Analyser and a coaxial line capacitive sensor. The permittivity and conductivity of tumours were 30% higher than that of the surrounding tissues due to their higher water content. The characteristic of less differentiation in tumours clearly was reflected in the dielectric properties, namely a smaller parameter for the relaxation time distribution of the tumour's dielectric relaxation. With the dielectric data, the power absorption ratios of tumour to surrounding tissue were calculated for four representative electromagnetic (EM) irradiation cases. The calculation shows that power absorption ratios are strongly dependent on the incident direction of the EM wave and optimum frequency. To improve therapeutic efficiency, it is appropriate to have the electric field vector (E) parallel to the interface of tumour/surrounding tissue at optimum frequencies around 100 MHz, and the case of E perpendicular to the interface must be avoided in applications of EM hyperthermia for brain tumours.

Tolerance to the cataleptic effect of the N-methyl-D-aspartate (NMDA) receptor antagonists in pigeons: cross-tolerance between PCP-like compounds and competitive NMDA antagonists

The effects of chronic administration of phencyclidine (PCP) or CGS 19755 (cis-4-phosphonomethyl-2-piperidine-carboxylic acid) on the cataleptic effects of N-methyl-D-aspartate (NMDA) receptor antagonists were studied in pigeons. PCP, a channel blocker of the NMDA receptor complex, or CGS 19755, a competitive NMDA antagonist, was administered i.m. to separate groups of pigeons each day. Tolerance developed to the cataleptic effects in both PCP- and CGS 19755-treated pigeons. PCP tolerance was characterized initially by 5-fold rightward shift and, with an increased chronic PCP dose, a complete downward shift of the PCP dose-effect curve. CGS 19755 tolerance was indicated by a 10-fold rightward shift of its dose-cataleptic effect curve. Cross-tolerance was obtained from PCP to other PCP-like compounds including dizocilpine (MK 801), ketamine, dextrorphan, 1-(2-thienyl)-cyclohexyl-piperidine and [(+)-SKF 10047] [(+)-N-allyl-normetazocine] as well as to the competitive NMDA antagonist, CGS 19755. Cross-tolerance also developed from CGS 19755 to another competitive NMDA antagonist, CGP 40116 [D-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid] as well as to PCP-like compounds. The pharmacological selectivity of tolerance was evident because there was equal sensitivity to etomidate or pentobarbital in tolerant and nontolerant pigeons. The symmetric cross-tolerance between PCP-like compounds and competitive NMDA antagonists suggests the cataleptic effects of the two classes of NMDA antagonists are probably mediated via a similar mechanism of inhibition of neurotransmission at the NMDA excitatory synapse.