Diffuse bile duct tumors: guidelines for management

The majority of patients with bile duct cancer have small focal adenocarcinomas localized to the upper, middle, or lower third of the bile duct. In contrast, a small subgroup of patients have been identified with bile duct tumors that are diffuse, involving multiple segments of the extrahepatic biliary tract. Among 186 patients with documented bile duct cancer treated at the UCLA Medical Center between 1954 and 1988, 13 patients (7%) had diffuse lesions. Patients with diffuse tumors had markedly poorer survival rates than did those with focal lesions. As diffuse tumors are not amenable to resection, surgical management consists primarily of establishing suitable biliary drainage. All patients with bile duct cancer should undergo careful intraoperative evaluation to exclude a diffuse lesion before tumor resection.

Bile duct carcinoma in the elderly. A rationale for surgical management

Recent studies have advocated the nonoperative treatment of elderly patients with bile duct cancer using biliary endoprostheses. In addition to a 30-day mortality rate of 9%, disadvantages with this approach include lack of a definitive diagnosis and the inability to assess resectability. For comparison, we reviewed 42 consecutive cases of bile duct cancer managed surgically at UCLA (from 1954 to 1988) among patients age 70 years or older. Histologic confirmation of bile duct cancer was obtained for 40 surgical patients (95%) in the series. The 30-day mortality rate was 10%. There was a trend to more aggressive surgical management during the study, with a concomitant doubling in survival rates (from 21% among patients treated between 1954 and 1978 to 53% among patients treated between 1979 and 1988 at 1 year after surgery.) We conclude that elderly patients should not be denied surgical evaluation of malignant neoplasms of the bile duct simply on the basis of age.

DNA forms of the geminivirus African cassava mosaic virus consistent with a rolling circle mechanism of replication

We have analysed DNA from African cassava mosaic virus (ACMV)-infected Nicotiana benthamiana by two-dimensional agarose gel electrophoresis and detected ACMV-specific DNAs by blot-hybridisation. ACMV DNA forms including the previously characterised single-stranded, open-circular, linear and supercoiled DNAs along with five previously uncharacterised heterogeneous DNAs (H1-H5) were resolved. The heterogeneous DNAs were characterised by their chromatographic properties on BND-cellulose and their ability to hybridise to strand-specific and double-stranded probes. The data suggest a rolling circle mechanism of DNA replication, based on the sizes and strand specificity of the heterogeneous single-stranded DNA forms and their electrophoretic properties in relation to genome length single-stranded DNAs. Second-strand synthesis on a single-stranded virus-sense template is evident from the position of heterogeneous subgenomic complementary-sense DNA (H3) associated with genome-length virus-sense template (VT) DNA. The position of heterogeneous virus-sense DNA (H5), ranging in size from one to two genome lengths, is consistent with its association with genome-length complementary-sense template (CT) DNA, reflecting virus-sense strand displacement during replication from a double-stranded intermediate. The absence of subgenomic complementary-sense DNA associated with the displaced virus-sense strand suggests that replication proceeds via an obligate single-stranded intermediate. The other species of heterogeneous DNAs comprised concatemeric single-stranded virus-sense DNA (H4), and double-stranded or partially single-stranded DNA (H1 and H2).

Mutational analysis of complementary-sense genes of African cassava mosaic virus DNA A

We have investigated the ability of African cassava mosaic virus DNA A mutants, containing disrupted complementary-sense genes, to infect Nicotiana benthamiana and to replicate in Nicotiana tabacum protoplasts. Three overlapping open reading frames (ORFs) with the capacity to encode proteins with an Mr greater than 10K (AC1, AC2 and AC3) are highly conserved between geminiviruses that infect dicotyledonous plants and one (AC4) is less well conserved. Of these, only AC1 is a prerequisite for DNA replication; disruption of this ORF rendered the DNA noninfectious in plants and prevented DNA replication in protoplasts. Disruption of ORF AC2 prevented plant infection but mutants were capable of autonomous replication and replicated DNA B in trans in protoplasts to produce DNA forms that comigrated with wild-type virus DNAs. The AC2 mutant phenotype suggests that the product of this ORF is involved in virus spread within the plant. Mutants in which ORF AC3 had been disrupted retained the ability to replicate and to infect plants systemically although symptom development was delayed and attenuated, and mutant DNA accumulated to much lower levels (10 to 20%) in comparison with wild-type infection. Typical geminate virus particles were observed in extracts of plants infected with ORF AC3 mutants indicating that this gene is not essential for coat protein synthesis or virus assembly but possibly acts by modulating virus levels in infected tissues. Disruption of ORF AC4 had no effect on infectivity or symptom development suggesting that this ORF is maintained only because it overlaps the highly conserved ORF AC1.

Activation of mouse peritoneal macrophages by maintenance in serum-free medium

Normal mouse peritoneal macrophages maintained in a serum-free medium for 48-72 h and then stimulated with phorbol myristate acetate, zymosan or bacteria, released large amounts of hydrogen peroxide. Opsonized zymosan and bacteria stimulated greater release than their unopsonized counterparts. Enhanced peroxide production was not a consequence of increased uptake of particles. Addition of serum to the serum-free medium abolished activation. The addition of interferon-gamma to the serum-free medium enhanced the effect of the serum-free treatment of macrophages from C3H/HeJ mice but abolished the effect of serum free treatment of macrophages from CFLP mice. The results are discussed in terms of negative regulation of receptor-oxidase linkage by serum.

Gastrointestinal complications after cardiac transplantation: a spectrum of diseases

Cardiac transplantation has become an accepted treatment modality for end-stage cardiac failure. The gastrointestinal (GI) tract represents a potential source of posttransplant morbidity and mortality. To define the scope of this problem, records of all patients undergoing cardiac transplantation at UCLA between January 1984 and July 1989 were reviewed. In all, there were 120 patients (90 males and 30 females) with a mean age of 45.4 yr. Among them, there were 61 patients (51%) who developed a total of 112 posttransplant GI complications. Of the entire 120 patients, 41 (34%) developed minor complications and 20 (17%) sustained major GI morbidity. Eighteen patients (15%) underwent either endoscopy or surgical intervention. These data suggest that most cardiac transplant recipients will experience some form of GI complication, although most are minor and can be managed conservatively. However, when major, life-threatening complications occur, evaluation and intervention should proceed expeditiously. The gastroenterologist and GI surgeon should play complimentary roles in the care of these complicated patients.

Early effects of colectomy and endorectal pullthrough operation on biliary lipid composition

In order to determine the effects of total colectomy and endorectal pullthrough with ileal reservoir (ERP) on biliary lipid composition in the early postoperative period, gallbladder bile of dogs was examined after biliary cannulation alone (control); biliary cannulation and colectomy with ileorectal anastomosis (IRA); and biliary cannulation, colectomy with mucosal proctectomy, and ERP. Bile collected from 3 to 6 weeks postoperation was analyzed for total bile acids, cholesterol, phospholipids, bilirubin, and calcium concentrations. Cholesterol saturation was calculated. Serum collected over the same period was analyzed for electrolytes and liver function tests. There was no evidence of sludge or gallstones post-operatively in any animal. Significant decreases in total bile acids, phospholipids, and calcium concentrations were noted in the bile of the IRA group when compared to the bile of the controls (P less than 0.05) and in total bile acids, cholesterol, phospholipids, and calcium in ERP vs controls (P less than 0.05). Moreover, all three biliary lipids and calcium were significantly decreased in ERP animals compared to those in the IRA group (P less than 0.05). No change in cholesterol saturation was noted between any of the three groups. Other than an increase in alkaline phosphatase concentrations compared to preoperative levels (P less than 0.05) which was noted in all groups, no significant changes were noted in serum parameters. We conclude that during the early postoperative period, ERP causes a significant decrease in gallbladder bile concentrations of total bile acids, cholesterol, phospholipids, and calcium which cannot be explained by colectomy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Susceptibility of Brassica species to cauliflower mosaic virus infection is related to a specific stage in the virus multiplication cycle

The relative susceptibilities and symptom responses of different Brassica species to infection by cauliflower mosaic virus (CaMV) have been compared and related to molecular events of the virus multiplication cycle. Variants of B. rapa (genome descriptor aa) were highly susceptible to infection by CaMV strain Cabb B-JI and contained relatively large amounts of virus; B. oleracea (cc) variants showed low susceptibility and contained small amounts of virus. B. nigra (bb) and allotetraploid species. B. juncea (aabb), B. napus (aacc) and B. carinata (bbcc), showed moderate responses to CaMV. CaMV unencapsidated DNA forms were isolated from different Brassica plants and examined by two-dimensional gel electrophoresis and blot hybridization. Viral RNA was estimated by dot blot analysis. These analyses showed differences in accumulation of key viral replication cycle intermediates within the broad range of host plants studied. The most susceptible species contained relatively small amounts of supercoiled (SC) DNA, a component of the CaMV mini-chromosome, but abundant viral transcripts and reverse transcription replication products. Tolerant plant hosts contained high levels of SC DNA but low levels of viral transcripts and reverse transcription DNA products. Allotetraploids contained SC DNA, RNA transcripts and replication product levels which were generally intermediate between those of their respective progenitor species. Evidence is presented that accumulation of CaMV SC DNA in the less susceptible host species is probably not due to autonomous DNA replication or tissue-specific expression. We conclude that a major component of the susceptibility of Brassica plants (and probably all CaMV host species) to CaMV infection is the level of viral minichromosome expression, influenced directly by the host genotype.

Changing patterns in diagnosis and management of bile duct cancer

An analysis of 186 patients treated for bile duct cancer at UCLA Medical Center from November 1954 to December 1988 demonstrated improvements in several areas of diagnosis and management. Comparison of 96 patients treated between 1954 and 1978 (group 1) with 90 patients treated between 1978 and 1988 (group 2) showed earlier diagnosis and treatment in group 2 (2.1 months from onset of symptoms) than in group 1 (4.9 months; p less than 0.05) and this was correlated with increased use of ultrasonography, computed tomographic (CT) scans, transhepatic cholangiography, and endoscopic retrograde cholangiopancreatography. Operative mortality rates were lower in group 2 (4%) than in group 1 (12%) and the difference was most marked in patients with upper-third lesions, where resections in group 1 had a 23% operative mortality rate but group 2 resected patients had zero mortality (p less than 0.001). A program of operative staging and selection of patients for resection or palliative procedures has resulted in better operative risks with no deterioration in survival.

Host regulation of the cauliflower mosaic virus multiplication cycle

The DNA genome of cauliflower mosaic virus (CaMV) replicates in the cytoplasm of infected plant cells by reverse transcription of an RNA template. Viral RNA is generated in the nucleus by transcription of an episomal minichromosome containing supercoiled DNA. We have assessed the relative activities of the nuclear and cytoplasmic phases of the CaMV multiplication cycle by monitoring unencapsidated viral DNA forms and polyadenylylated RNAs in different organs of one host plant and in different host species. Systemically infected leaves of a highly susceptible host, turnip (Brassica rapa), contained abundant 35S RNA and 19S RNA transcripts and unencapsidated reverse transcription products but relatively little supercoiled DNA. In contrast, supercoiled DNA accumulated in roots and other tissues of turnip plants but without significant amounts of steady-state viral RNA. Infected but asymptomatic leaves of a less susceptible CaMV host, kohlrabi (Brassica oleracea), contained supercoiled DNA almost exclusively but negligible viral RNA and DNA products of reverse transcription. An allotetraploid species, rape (Brassica napus), exhibited infection characteristics and minichromosome expression levels intermediate between the other two species from which it was derived. We conclude that expression of the CaMV minichromosome is a key phase of the virus multiplication cycle, which is regulated differentially in organs of a highly susceptible host species. Furthermore, this regulation exhibits genetic variation among different Brassica species and controls host susceptibility to CaMV infection.

Characterization of a loss-of-function mutation in the isopenicillin N synthetase gene of Acremonium chrysogenum

The N-2 strain of Acremonium chrysogenum accumulates the beta-lactam precursor tripeptide delta-(L-alpha-amino-adipoyl)-L-cysteinyl-D-valine and has no discernible activity for three of the cephalosporin C (Ce) biosynthetic enzymes. This phenotype is consistent with a mutation either within pcbC [the isopenicillin N synthetase (IPNS)-encoding gene] or in a pathway-regulator gene. To distinguish these possibilities we have cloned and sequenced pcbC from strain N-2. There is a single C----T mutation at nt 854 within the coding sequence, changing aa 285 from proline to leucine. An IPNS-specific monoclonal antibody recognises a catalytically inactive IPNS protein in extracts of N-2 cells. These findings suggest that strain N-2 carries a simple IPNS mutation and that IPNS or its biosynthetic product isopenicillin N is involved in regulation of the later stages of the Ce biosynthetic pathway.

Effect of Streptococcus pneumoniae on human respiratory epithelium in vitro

A total of 11 of 15 Streptococcus pneumoniae culture filtrates and all five bacterial autolysates produced by cell death in the stationary phase caused slowed ciliary beating and disruption of the surface integrity of human respiratory epithelium in organ culture. This effect was inhibited by cholesterol and was heat labile and reduced by standing at room temperature but was stable at -40 degrees C. The activity was detected at the late stationary phase of culture and was associated with the presence of hemolytic activity. Gel filtration of a concentrated culture filtrate and autolysate both yielded a single fraction of approximately 50 kilodaltons which slowed ciliary beating and were the only fractions with hemolytic activity. Rabbit antiserum to pneumolysin, a sulfhydryl-activated hemolytic cytotoxin released by S. pneumoniae during autolysis, neutralized the effect of the culture filtrate on respiratory epithelium. Both native and recombinant pneumolysin caused ciliary slowing and epithelial disruption. Electron microscopy showed a toxic effect of pneumolysin on epithelial cells: cytoplasmic blebs, mitochondrial swelling, cellular extrusion, and cell death, but no change in ciliary ultrastructure. Recombinant pneumolysin (10 micrograms/ml) caused ciliary slowing in the absence of changes in cell ultrastructure. Release of pneumolysin in the respiratory tract during infection may perturb host defenses, allowing bacterial proliferation and spread.

Erythropoiesis in pregnancy

The reticulocyte count, serum ferritin and serum erythropoietin concentrations were measured during the course of pregnancy in 41 women. A decrease in iron stores early in pregnancy was accompanied by a significant rise in the reticulocyte count until the 28th week. Erythropoietin levels did not rise significantly until the 28th week of pregnancy and had fallen to the post-natal level by 40 weeks. The results are consistent with an increase in erythropoietic activity early in pregnancy which did not appear to depend upon increased plasma erythropoietin levels.

Infectious RNA derived by transcription from cloned cDNA copies of the genomic RNA of an insect virus

RNA transcripts of cloned cDNA of the genomic RNAs of BBV (black beetle virus) are infectious to cultured cells of Drosophila melanogaster. Individual transcripts had approximately 10% of the infectivity of the corresponding authentic virion RNA. Progeny virus resulting from transcript infection was phenotypically indistinguishable from the progenitor virus used to generate the original cDNA forms as judged by sucrose density gradient sedimentation, specific infectivity, plaque morphology, and serology. Although the transcript RNAs used to produce this virus had 20 nonviral bases headed by a capping group at their 5' termini, these 20 bases were absent in the progeny viral RNAs. The cDNA forms, and therefore the resulting transcript RNAs, should be readily modifiable by the techniques of recombinant DNA technology both for viral studies and for the insertion of foreign genes into the viral genome and thus into the host cytoplasm.

Template-dependent RNA polymerase from black beetle virus-infected Drosophila melanogaster cells

Infection of cultured cells of Drosophila melanogaster with black beetle virus (BBV) induces an RNA polymerase that is bound to cellular particulate material in a complex with a template RNA. We have solubilized the polymerase by treatment of the relevant particulates with detergents such as dodecyl-beta-D-maltoside. The polymerase activity was made dependent upon exogenous RNA by destruction of the endogenous template RNA with micrococcal nuclease. Addition of BBV RNA1 or RNA2 induced synthesis of full-length negative-strand RNA isolated as a double-stranded complex with the added RNA. Newly synthesized plus strands were also detected in the RNA2 complexes. Certain other viral RNAs also induced synthesis of their negative strands.

Effect of ileal and intravenous infusions of fat emulsions on feeding and satiety in human volunteers

The effect of ileal infusion of a lipid emulsion, containing 50% corn oil and 3% albumen, on food intake and satiety was measured in paired experiments carried out in 6 healthy volunteers. Subjects ate for shorter periods of time during ileal infusions of fat emulsion compared with control infusions of albumen and saline (25 +/- 1 vs. 32 +/- 3 min, mean +/- SEM) and consumed a smaller amount of food (670 +/- 23 g vs. 884 +/- 89 g) and energy (1016 +/- 79 kcal vs. 1591 +/- 228 kcal). The quantity of liquid drunk and the rates of eating and drinking were not significantly affected by the infusion of fat emulsion. In a further series of experiments carried out in 5 normal volunteers, ileal infusion of corn oil emulsions delayed gastric emptying compared with ileal infusion of albumen and saline (t1/2 = 203 +/- 48 vs. 68 +/- 12 min, p less than 0.02). The possibility that the observed reductions in food intake were related to the effect of absorbed fat was investigated in 6 healthy volunteers during intravenous infusion of either fat emulsion or isosmotic saline. Food intake was not affected by intravenous infusion of lipid. Our results suggest that lipid may interact with ileal receptors to induce early satiety and reduce the amount of food consumed. The earlier inhibition of food intake during lipid infusion is perhaps best explained by early gastric distention caused by delayed gastric emptying, though the data would not exclude the release of an ileal mechanism, which has a direct action on the satiety centers.

Recombination and oligonucleotide analysis of guanidine-resistant foot-and-mouth disease virus mutants

Guanidine resistance (gr) mutations of foot-and-mouth disease virus were mapped by recombining pairs of temperature-sensitive mutants belonging to different subtypes. In each cross, one parent possessed a gr mutation. Recombinants were isolated by selection at the nonpermissive temperature and assayed for the ability to grow in the presence of guanidine. From the progeny of three crosses, four different types of recombinant were distinguished on the basis of protein composition and RNA fingerprint. The sequences of the RNase T1-resistant oligonucleotides were determined and located in the full-length sequence of foot-and-mouth disease virus. The resulting maps show that (i) each recombinant was generated by a single genetic crossover, and (ii) both of the gr mutations studied were located within an internal 2.9-kilobase region which spans the P34 gene. This supports our hypothesis that guanidine inhibits the growth of foot-and-mouth disease virus by acting on nonstructural polypeptide P34. Additional evidence was provided by RNA fingerprinting gr mutants. In two of four cases the gr mutation was associated with a change in an oligonucleotide located near the 3' end of the P34 gene; in one of these the nucleotide substitution was identified.

Multiple sites of recombination within the RNA genome of foot-and-mouth disease virus

Recombinant foot-and-mouth disease viruses were isolated from cells infected with a mixture of temperature-sensitive (ts) mutants belonging to different subtype strains. In order to select for recombination events in many different regions of the genome, crosses were performed between various pairs of mutants, with ts mutations in different regions of the genome. ts+ progeny were analysed by electrofocusing virus-induced proteins and RNase T1 fingerprinting of their RNA. All but 5 out of 43 independent isolates, from nine crosses, proved to have recombinant RNA genomes. Maps of these genomes, based on a knowledge of the locations of the unique oligonucleotides, were constructed. Most could be interpreted as being the products of single genetic cross-overs, although three recombinants were formed by two cross-overs each. Cross-overs in at least twelve distinct regions of the genome were identified. This evidence of a large number of recombination sites suggests that RNA recombination in picornaviruses is a general, as opposed to a site-specific, phenomenon.

Guanidine-resistant mutants of aphthovirus induce the synthesis of an altered nonstructural polypeptide, P34

Extracts of cells infected with guanidine-resistant mutants of aphthovirus were examined for differences in virus-induced polypeptides by using electrofocusing. Four of 1 independent spontaneous mutants induced the synthesis of an altered nonstructural polypeptide, P34. The precursor of P34, P52, and a previously unmapped polypeptide, P20c, also carried these charge-change mutations. No mutations in other regions of the genome were detected, and the remaining six guanidine-resistant mutants appeared entirely normal by electrofocusing. However, when the P34 of one of the latter mutants was examined by tryptic peptide fingerprinting, it too differed from that of the guanidine-sensitive parent. The frequency of P34 alterations among guanidine-resistant mutants suggests that P34 is functionally involved in the antiviral action of guanidine.

Effect of mutation on the virulence in mice of a strain of foot-and-mouth disease virus

Twenty-eight mutations, representing mutation in five different polypeptide-coding regions of the foot-and-mouth disease genome, were examined for their effect on the virulence of the virus for suckling mice. Five types of mutation were examined: temperature-sensitive (ts), electrophoretic (e), co-variant temperature-sensitive and electrophoretic (ts/e), guanidine-resistant (gs+) and putative co-variant guanidine-resistant and electrophoretic (gs+/e). All the ts mutations and three out of the 11 non-ts mutations produced some reductions in virulence. In the majority of cases this reduction in virulence was shown to co-vary with the mutation. No correlation was observed between the site of a mutation or its 'cut-off' temperature and the extent of the reduction in virulence. Studies of the growth in vivo of a small selection of ts mutants suggested that for most mutants their reduced virulence was a trivial effect of their slow growth rate. With one exception they all eventually grew to parental virus levels, the resulting virus being temperature-sensitive and the disease indistinguishable from that caused by the parental virus. The one exception was an avirulent ts mutant which only grew to one-thousandth the titre of the parent virus. This mutant did not cause disease and was therefore considered to be the only avirulent mutant. Its mutation was in the coat protein-coding region of the genome, probably the region coding for VP3.

The platelet count in pregnancy

The platelet count was measured at approximately monthly intervals during the course of 44 normal pregnancies. There was no evidence of any fall in the platelet count during pregnancy. Any significant change in the platelet count in pregnant women is unlikely to be the result of a normal pregnancy.