Effect of caponization and testosterone implantation on hepatic lipids and lipogenic enzymes in male chickens

This study was conducted to determine the role and effects of testosterone in lipogenesis by measuring and analyzing the lipid composition and lipogenic enzyme activity of livers from capons treated with various doses of exogenous testosterone implant. Healthy and uniform male Single Comb White Leghorn chickens were caponized at 12 wk of age. Sixteen-week-old capons were randomly selected for a 10-wk experiment. Fifteen intact males and 15 capons were used for trial 1. In trial 2, 10 sham-operated males and 40 capons were used. The capons were randomly divided into 4 independent treatments with sialistic implants of cholesterol (1.62 mm i.d., 3.6 mm o.d., 9.24 +/- 0.36 mg; CHOL), low testosterone (1 mm i.d., 3 mm o.d., 5.88 +/- 0.23 mg), medium testosterone (1.62 mm i.d., 3.16 mm o.d., 9.81 +/- 0.17 mg), or high testosterone (2 mm i.d., 4 mm o.d., 16.7 +/- 0.24 mg). In trial 1, the results showed that caponization increased total hepatic lipid and triacylglycerol contents and decreased the nonesterified fatty acid content (P < 0.05) compared with the intact male. Meanwhile, caponization increased nicotinamide adenine dinucleotide phosphate -malic dehydrogenase (MDH) activity and MDH mRNA content (P = 0.09) simultaneously. In trial 2, comparing treatments with the various implantation doses of testosterone, the liver triacylglycerol content of capons the medium-dose implantation was decreased as compared with those receiving CHOL (P < 0.05). The total lipid and phospholipid contents of liver were decreased in capons receiving the high-dose implantation (P < 0.05), whereas the relative weight and nonesterified fatty acid content were increased (P < 0.05) and reached the same level as those in the sham treatment (P > 0.05). With an increased implantation dose, MDH activity of capons receiving the medium dose or higher was not different from those receiving the CHOL and sham treatments (P > 0.05). The increase in MDH activity at the transcriptional and translational levels suggests that caponization may positively regulate hepatic lipogenesis. In contract, implantation of testosterone up to the threshold concentration depressed hepatic lipogensis and lipid accumulation.

Assessing the prevalence of Salmonella enterica in poultry hatcheries by using hatched eggshell membranes

Salmonella enterica causes a number of significant poultry diseases and is also a major pathogen in humans. Most poultry infected by Salmonella become carriers; infection may also be fatal, depending on the particular serovar and the age of the bird at infection. Younger birds are more susceptible to infection by Salmonella, so it is critical that hatcheries monitor birds. We developed a method to use hatched eggshell membranes (HEM) to assess contamination by Salmonella in poultry hatching cabinets and to evaluate the prevalence of Salmonella in a goose hatchery and rearing farm. Comparison of the Salmonella isolation rate in hatching cabinets using 3 sampling methods showed that the highest Salmonella contamination was detected in HEM, and that these results differed significantly from those obtained from fluff samples and cabinet swab samples (P < 0.05). Analysis of HEM was also used to evaluate Salmonella contamination in goose, chicken, and duck hatcheries. The lowest Salmonella-positive rate was found for the chicken hatchery, followed by the goose and the duck hatcheries (P < 0.05). Six serogroups of Salmonella were detected in the 3 hatcheries: A, B, C1, C2, D, and E. The distribution of these serogroups differed among the hatcheries. Salmonella serogroup C1 was the major serogroup found in geese, compared with serogroup B in chickens and ducks. However, Salmonella Typhimurium was dominant in 1 goose hatchery and also in geese from this hatchery that had been transferred to a farm. Antibiotic susceptibility analysis showed that Salmonella Typhimurium strains isolated from the farm geese with diarrhea showed significantly higher resistance to doxycycline, colistin, sulfamethoxazole-trimethoprin, and cephalothin than those isolated from the hatchery (P < 0.05). Therefore, HEM as a detection target can be used to monitor Salmonella contamination in hatching cabinets and also be used to assess Salmonella prevalence in poultry hatcheries and rearing farms.

Prospective evaluation of front-line chemo-immunotherapy (C-IT) with oregovomab (2 alternative dosing schedules) carboplatin-paclitaxel (C-P) in advanced ovarian cancer (OC)

3024

Background: Chemotherapy (C) induced bone marrow suppression has been assumed to inhibit the generation of augmented immune responses. This has limited investigation of front-line C-IT in OC. Temporal relationship of IT administration relative to C has not been established. Oregovomab is a CA125 specific MAb in development as an OC adjuvant treatment to induce tumor specific immunity. Methods: Patients (pts) awaiting staging laparotomy for presumptive OC were consented to the study and contributed primary tumor samples. Qualifying pts were subsequently randomized to concurrent C-IT with antibody administered at cycles 1, 3, and 5 (Arm A) or 8 ± 2 days following cycles 1, 3, and 5 (Arm B) of standard C-P. Both arms received additional infusions of oregovomab every 12 weeks until progression; response to C-IT was assessed at 36 weeks. Results: Forty stage III/IV pts (18 Arm A; 22 Arm B) were randomized and dosed. More pts in Arm A (39%) were stage IV vs Arm B (14%) however 27% of Arm B pts had >2cm residual disease vs. 11% in Arm A. Complete clinical response (CR) to surgery and C-IT was achieved in 15 pts (83%) in Arm A and 17 pts (77%) in Arm B. For pts with = 2 cm residual disease, 88% in Arm A had = 65 U/mL CA125 prior to/at cycle 3, normalized CA125 and a CR post C-IT compared to 75% of pts in Arm B. Robust Ab2 antibody response (>100 ng/mL) was achieved in 94% of Arm A and 68% of Arm B pts. The immune response developed earlier in Arm A. After one injection of oregovomab, 31% of pts in Arm A vs. 0% in Arm B generated HAMA > 3000 ng/mL and Ab2 > 100 ng/mL (P=0.016 Fisher’s Exact Test). Such an early and vigorous response pattern has not been seen in previous oregovomab studies which have not included concomitant front-line C. There were no IT related serious adverse events. Conclusions: Contrary to expectations, concurrent C-P resulted in enhanced immune stimulation with oregovomab. Interestingly, concurrent infusion of oregovomab was more immunogenic than delayed infusion. Clinical activity was favorable and safety profiles were similar to that expected for C alone. Further randomized evaluation of front-line CP-oregovomab vs CP is warranted.

[Table: see text]

Characterisation of plasmids encoding CTX-M-3 extended-spectrum β-lactamase from Enterobacteriaceae isolated at a university hospital in Taiwan

CTX-M-3 is the most common extended-spectrum beta-lactamase produced by Enterobacteriaceae in Taiwan. The present study was conducted to characterise the genetic environment surrounding bla(CTX-M-3). A total of 11 ceftriaxone-resistant isolates were studied: Escherichia coli (n=4), Klebsiella pneumoniae (n=5) and Salmonella enterica serotypes Anatum (SA831R) and Potsdam (SC72). Molecular methods used included polymerase chain reaction, sequencing, DNA-DNA hybridisation, conjugation, physical mapping and restriction fragment length polymorphism (RFLP) analysis. All isolates examined carried bla(CTX-M-3) on large plasmids (>70kb). The resistance plasmids of the two Salmonella and two K. pneumoniae strains (KP104 and KP116) were confirmed to be conjugative in vitro. RFLP analysis indicated that the plasmids were different. Physical mapping also revealed the difference between the two Salmonella plasmids, pSA831R (82kb) and pSC72 (74kb). An insertion sequence, ISEcp1, was found upstream of each bla(CTX-M-3) gene. However, sequencing of downstream regions of the bla genes showed two different patterns: the presence of orf477 in pSA831R and of orf1-mucA in pSC72, pKP104 and pKP116. IncI1-type oriT and nikA sequences were present in the plasmids of all the clinical isolates tested, except S. Anatum. Different bla(CTX-M-3)-carrying plasmids were identified among the enterobacteria studied. The presence of ISEcp1 in all isolates may be associated with the widespread resistance among Enterobacteriaceae. Although the plasmids were not identical, they appeared to belong to the same incompatibility group (IncI1-like plasmids), suggesting that they are genetically related but may have evolved divergently over time.

Integron-associated imipenem resistance in Acinetobacter baumannii isolated from a regional hospital in Taiwan

We investigated the genetic properties of imipenem-resistant Acinetobacter baumannii collected from a regional hospital in Taiwan. Pulsed-field gel electrophoresis demonstrated that the isolates were genetically diverse. Polymerase chain reaction, DNA sequencing, and DNA-DNA hybridisation showed that the bla(IMP-1) gene resided as a cassette in a plasmid-borne class 1 integron in two isolates. The majority of the resistant isolates were plasmid-less and carried no bla(IMP), bla(VIM) or bla(CFI) genes, indicating that other uncharacterised metallo-beta-lactamases or mechanisms other than enzyme production are involved in carbapenem resistance in this group of A. baumannii. We conclude that multidrug resistance of A. baumannii was a combined effect of lateral gene transfer and clonal spread of multiple resistant clones. Strict measures should be implemented to control the further spread of resistance.

Isolation of Salmonella enterica serotype choleraesuis resistant to ceftriaxone and ciprofloxacin

Salmonella enterica serotype choleraesuis (S choleraesuis) usually causes systemic infections in man that need antimicrobial treatment. We isolated a strain of S choleraesuis that was resistant to ceftriaxone and ciprofloxacin from a patient with sepsis. Ciprofloxacin resistance was associated with mutations in gyrA and parC, whereas the ampC gene (bla(CMY-2)), responsible for ceftriaxone resistance, was carried by a transposon-like mobile element. This element was found inserted into finQ of a potentially transmissible 140 kb plasmid, with an 8 bp direct repeat flanking the junction regions. The appearance of this resistant S choleraesuis is a serious threat to public health, and thus constant surveillance is warranted.

What motivates interest in attending a familial cancer genetics clinic?

The motivation of people who seek advice about a family history of cancer was explored in a cross sectional study of new cancer referrals to five regional cancer genetics centres in England: the PACT (patient and clinical team) psychosocial study. One hundred sixty-two people took part. Measures were source of referral, estimated and perceived cancer risk, level of cancer worry, and personal and family-centred reasons for wanting to be seen in clinic. General practitioners referred more people than hospital doctors, and referred a larger proportion of people at low genetic risk of developing cancer. More than half of the participants had been the first to raise the issue of their family history of cancer. Personal motivation for referral is clearly different for those who have had a diagnosis of cancer and for those with children, compared to unaffected and childless people, and is characterised by altruistic concern for other family members rather than a perception of increased personal risk. Men and people from ethnic minorities are very significantly under-represented. Understanding people's motivation may be useful in targeting genetic counselling for people with a family history of cancer.

Image-directed parathyroidectomy under local anaesthesia in the elderly

BACKGROUND

Surgical morbidity and mortality rates are increased in elderly patients. The aim of this study was to evaluate the outcome of targeted parathyroid operations in patients over the age of 70 years.

METHODS

Forty patients aged over 70 years underwent targeted parathyroidectomy for primary hyperparathyroidism (HPT). Data were collected prospectively and reviewed retrospectively.

RESULTS

: There were 33 women and seven men with a mean age of 78 (range 70-92) years, all of whom had symptoms attributable to HPT. A solitary parathyroid adenoma was detected by ultrasonography and/or sestamibi scintigraphy before operation in all patients. Six patients had a history of neck surgery, including two with persistent or recurrent HPT. Thirty-three patients underwent neck exploration under local anaesthesia with intravenous sedation. Following parathyroidectomy, intraoperative parathyroid hormone levels normalized in 39 of 40 patients and accurately predicted postoperative eucalcaemia. Intraoperative findings included 37 solitary adenomas, one double adenoma and two carcinomas. One patient with persistent HPT developed severe hypoparathyroidism following targeted parathyroid exploration with autotransplantation. Twenty-nine patients were discharged from hospital on the day of surgery. Nineteen of 21 patients for whom data were available reported an improvement in symptoms.

CONCLUSION

A focused neck exploration provides a safe and effective alternative to bilateral neck exploration in elderly patients in whom a solitary parathyroid adenoma has been localized before operation. Targeted parathyroidectomy under local anaesthesia is recommended in most elderly patients with HPT.

Fabrication and characterization of hydroxyapatite reinforced with 20 vol % Ti particles for use as hard tissue replacement

Hydroxyapatite(HA)-based composite reinforced with 20 vol % titanium (Ti) particles was fabricated by hot pressing based on the studies of the structural stability of HA phase in HA-Ti composite by means of FTIR spectrometry and X-ray diffractometry. The mechanical properties and biological behaviors of the composite were investigated by mechanical and in vivo studies. The existence of Ti metal phase can promote the dehydration and decomposition of HA ceramic phase into the more stable calcium phosphate phases, such as alpha-Ca(3)(PO(4))(2) (alpha-TCP) and Ca(4)O(PO(4))(2) at high temperatures. Comparing with pure HA ceramic manufactured under the same conditions, HA-20 vol % Ti composite with higher fracture toughness (0.987 MPa m(1/2)), bending strength (78.59 MPa), work of fracture (12.8J/m(2)), porosity (9.8%) and lower elastic modulus (75.91 GPa) is more suitable for use as hard tissue replacement. Crack deflection is the chief toughening mechanism in the composite. Histological evaluation by light microscope shows HA-20 vol % Ti composite implant could be partially integrated with newborn bone tissues after 3 weeks and fully osteointegrated at 12 weeks in vivo. The excellent biological properties of HA-20 vol % Ti composite may be contributed to the coexistence of high porosity and the decomposition products of HA phase in the composite.

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS)

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS) is in progress. The study design, accrual to date, and related research projects are described. Revised accrual rates and expected recruitment are given. 15 cancers have been detected to date, from a total of 1236 screening measurements. This event rate and the tumour grades reported are compared with recent reports from other studies in women at high risk of breast cancer.

Phosphorylation-dependent ubiquitination of cyclin E by the SCFFbw7 ubiquitin ligase

Cyclin E binds and activates the cyclin-dependent kinase Cdk2 and catalyzes the transition from the G1 phase to the S phase of the cell cycle. The amount of cyclin E protein present in the cell is tightly controlled by ubiquitin-mediated proteolysis. Here we identify the ubiquitin ligase responsible for cyclin E ubiquitination as SCFFbw7 and demonstrate that it is functionally conserved in yeast, flies, and mammals. Fbw7 associates specifically with phosphorylated cyclin E, and SCFFbw7 catalyzes cyclin E ubiquitination in vitro. Depletion of Fbw7 leads to accumulation and stabilization of cyclin E in vivo in human and Drosophila melanogaster cells. Multiple F-box proteins contribute to cyclin E stability in yeast, suggesting an overlap in SCF E3 ligase specificity that allows combinatorial control of cyclin E degradation.

Differences in mesenchymal tissue repair

Variations in certain mesenchymal tissue healing processes are not widely recognized. The current review summarizes key differences in healing mechanisms and healing potential after injury to soft tissues having different healing outcomes.

Large drug resistance virulence plasmids of clinical isolates of Salmonella enterica serovar Choleraesuis

Salmonella enterica serovar Choleraesuis generally causes systemic human salmonellosis without diarrhea, and therefore, antimicrobial treatment is essential for such patients. The drug resistance information on this organism is thus of high value. Serovar Choleraesuis usually harbors a virulence plasmid (pSCV) of 50 kb in size. Of the 16 clinical isolates identified to be serovar Choleraesuis, all except one harbored a pSCV and seven of them carried a pSCV of more than 125 kb in size. A pSCV was defined as a plasmid carrying spvC and characteristic deletions detected by PCR and by DNA-DNA hybridization (for the former criterion). The results of PCR, restriction fragment profiles, and Southern DNA-DNA hybridizations of the profiles all indicated that such larger pSCVs were derived from the 50-kb plasmid recombined with non-pSCVs found in some clinical isolates. Fifteen of the 17 strains, including a laboratory strain, were then tested for drug resistance against 16 antibiotics with E-test and the dilution method. The laboratory strain, which harbored a 50-kb pSCV and a 6-kb non-pSCV, was resistant only to sulfonamides (SUL), and its resistance gene, sulII, checked with PCR and DNA-DNA hybridization, was located on the 6-kb non-pSCV. All 14 clinical strains were resistant to multiple drugs. Of the 14, 7 were resistant to SUL, and the resistance gene was located on a plasmid. The sulII gene, but not bla(TEM-1), was carried only on the 6-kb non-pSCV. Of the remaining six large plasmids, three of 90 kb, two of 136 kb, and one of 140 kb, the last three were pSCVs and carried the other SUL gene (sulI) and the bla(TEM-1) gene. The six strains were also resistant to trimethoprim-sulfamethoxazole. None of the 50-kb pSCVs carried resistance genes. These drug resistance genes on the large pSCVs were apparently also acquired through recombination.

Potential cost-effectiveness of one-time screening for lung cancer (LC) in a high risk cohort

The development of low-dose helical computed-tomography (CT) scanning to detect nodules as small as a few mm has sparked renewed interest in lung cancer (LC) screening. The objective of this study was to assess the potential health effects and cost-effectiveness of a one-time low-dose helical CT scan to screen for LC. We created a decision analysis model using baseline results from the Early Lung Cancer Action Project (ELCAP); Surveillance, Epidemiology and End Results (SEER) registry public-use database; screening program costs estimated from 1999 Medicare reimbursement rates; and annual costs of managing cancer and non-cancer patients from Riley et al. (1995) [Med Care 1995;33(8):828-841] and Taplin et al. (1995) [J Natl Cancer Inst 1995;87(6):417-26]. The main outcome measures included years of life, cost estimates of baseline diagnostic screening and follow up, and cost-effectiveness of screening. We found that in a very high-risk cohort (LC prevalence of 2.7%) of patients between 60 and 74 years of age, a one-time screen appears to be cost-effective at $5940 per life year saved. In a lower risk general population of smokers (LC prevalence of 0.7%), a one-time screen appears to be cost-effective at $23100 per life year. Even when a lead-time bias of 1 year is incorporated into the model for a low risk population, the cost-effectiveness is estimated at $58183 per life year. Based on the assumptions embedded in this model, one-time screening of elderly high-risk patients for LC appears to be cost-effective.

Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study

Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors.

Identification of the E2A gene products as regulatory targets of the G1 cyclin-dependent kinases

The E2A gene products, E12 and E47, are multifunctional transcription factors that as homodimers regulate B cell development, growth, and survival. In this report, the E2A gene products are shown to be targets for regulation by the G1 cyclin-dependent kinases. Two novel G1 cyclin-dependent kinase sites are identified on the N-terminal domain of E12/E47. One site displays homology to a preferential D-type cyclin-dependent kinase site (serine 780) on the retinoblastoma susceptibility gene product (pRB) and, consistent with this homology, is more efficiently phosphorylated by cyclin D1-CDK4 than by the other cyclin-dependent kinases (CDK) that were tested. The second kinase site is phosphorylated by both cyclin D1-CDK4 and cyclin A/E-CDK2 complexes. Mutation studies indicated that phosphorylation of the cyclin D1-CDK4 site, or more potently, of both the cyclin D1-CDK4 and cyclin A/E-CDK2 sites, negatively regulates the growth suppressor function associated with the N-terminal domain of E12/E47. Transient expression studies showed that ectopic expression of cyclin D1 or E negatively regulates sequence-specific activation of gene transcription by E12/E47. Analysis of site mutants, however, indicated that inhibition of E12/E47 transcriptional activity did not require the N-terminal G1 cyclin-dependent kinase sites. Together, the results suggest that the growth suppressor and transcriptional activator functions of E12/E47 are targets for regulation by G1 cyclin-dependent kinases but that the mechanisms of regulation for each function are distinct.

Lack of evidence of an association between the carriage of virulence plasmid and the bacteremia of Salmonella typhimurium in humans

The involvement of the virulence plasmid (pSTV) of Salmonella typhimurium in human salmonellosis was examined. Most of the 224 clinical strains isolated from the blood (53) and nonblood samples (171) contained a 90 kb or larger plasmid, most of which were pSTV. The rates of pSTV carriage in the isolates showed no statistically significant difference between those derived from the blood and those from other sources (87% vs. 83%; chi2=0.49, 0.1<P<0.9), suggesting that pSTV may not play a critical role in promoting S. typhimurium bacteremia in humans. Nine strains with representative plasmid profiles were tested for the mouse virulence. The result revealed that these clinical isolates contained all three virulent types known: the avirulent, the highly virulent when a pSTV was present, and the moderately virulent regardless of the presence or absence of pSTV. This indicated that mouse virulence of S. typhimurium did not correlate their virulence in humans. Clinical data showed that most patients with primary bacteremia had underlying immunosuppressive diseases, whereas only a few patients with secondary bacteremia had preexisting diseases (87% vs. 13%; chi2=22.73, P<0.005). It is suggested that the contribution of pSTV to S. typhimurium bacteremia in humans is likely to be limited, and both the host factor and the microbial virulence determinants on the chromosome are more important than virulence plasmid in predisposing patients to bacteremia.

Safety and immunogenicity of improved Shigella O-specific polysaccharide-protein conjugate vaccines in adults in Israel

Data suggest that the O-specific polysaccharide (O-SP) domain of the lipopolysaccharide (LPS) of Shigella species is both an essential virulence factor and a protective antigen and that a critical level of serum immunoglobulin G (IgG) to this antigen will confer immunity to shigellosis. Because covalent attachment of polysaccharides to proteins increases their immunogenicity, especially in infants and in young children, the O-SP of Shigella species were bound to medically useful proteins, and the safety and immunogenicity of the resultant conjugates were confirmed in adults and 4- to 7-year-old children. Succinylation of the carrier protein improved the immunogenicity of Shigella conjugates in mice and increased their yield. Based on these results, a clinical trial of O-SP conjugates of Shigella sonnei and Shigella flexneri 2a bound to succinylated mutant Pseudomonas aeruginosa exotoxin A (rEPAsucc) or native or succinylated Corynebacterium diphtheriae toxin mutant (CRM9 or CRM9succ) was conducted in healthy adults. The conjugates were safe and immunogenic. S. sonnei-CRM9, S. sonnei-CRM9succ, and S. sonnei-rEPAsucc elicited significant rises of geometric mean (GM) IgG anti-LPS within 1 week of injection (P < 0.001). At 26 weeks, the GM anti-LPS levels elicited by these three conjugates were similar and higher than their prevaccination levels (P < 0.0001). GM IgG anti-LPS levels elicited by S. flexneri 2a-rEPAsucc were significantly higher than those elicited by S. flexneri 2a-rCRM9succ at all intervals after injection. At 26 weeks, the levels of IgG anti-LPS in vaccinees were higher than their prevaccination levels (P < 0.0001). The serum antibody responses were specific, as there was no significant rise of anti-LPS to the heterologous O-SP in any vaccinee. Both conjugates elicited statistically significant rises of serum antibodies to the injected carrier protein. At 6 months, these five Shigella conjugates elicited higher fold rises than similar conjugates (D. N. Taylor et al., Infect. Immun. 61:3678-3687, 1993). Based on these data, we chose S. sonnei-CRM9 and S. flexneri 2a-rEPAsucc for evaluation in children.

Linkage analysis of systemic lupus erythematosus induced in diabetes-prone nonobese diabetic mice by Mycobacterium bovis

Systemic lupus erythematosus induced by Mycobacterium bovis in diabetes-prone nonobese diabetic mice was mapped in a backcross to the BALB/c strain. The subphenotypes-hemolytic anemia, antinuclear autoantibodies, and glomerular immune complex deposition-did not cosegregate, and linkage analysis for each trait was performed independently. Hemolytic anemia mapped to two loci: Bah1 at the MHC on chromosome 17 and Bah2 on distal chromosome 16. Antinuclear autoantibodies mapped to three loci: Bana1 at the MHC on chromosome 17, Bana2 on chromosome 10, and Bana3 on distal chromosome 1. Glomerular immune complex deposition did not show significant linkage to any genomic region. Mapping of autoantibodies (Coombs' or antinuclear autoantibodies) identified two loci: Babs1 at the MHC and Babs2 on distal chromosome 1. It has previously been reported that genes conferring susceptibility to different autoimmune diseases map nonrandomly to defined regions of the genome. One possible explanation for this clustering is that some alleles at loci within these regions confer susceptibility to multiple autoimmune diseases-the "common gene" hypothesis. With the exception of the H2, this study failed to provide direct support for the common gene hypothesis, because the loci identified as conferring susceptibility to systemic lupus erythematosus did not colocalize with those previously implicated in diabetes. However, three of the four regions identified had been previously implicated in other autoimmune diseases.

Delayed presentation of a posttraumatic perirenal urinoma in a 6-year-old boy

A 6-year-old boy presented with a perirenal urinoma over the left flank about 3 months following trauma. Delayed presentation of a post-traumatic perirenal urinoma is rare in children, and percutaneous catheter drainage was effective in this case.

Biopharmaceutics of transmucosal peptide and protein drug administration: role of transport mechanisms with a focus on the involvement of PepT1

Non-invasive delivery of peptide and protein drugs will soon become a reality. This is due partly to a better understanding of the endogenous transport mechanisms, including paracellular transport, endocytosis, and carrier-mediated transport of mucosal routes of peptide and protein drug administration. This paper focuses on work related to the elucidation of structure-function, intracellular trafficking, and regulation of the intestinal dipeptide transporter, PepT1.

Treatment with succinic anhydride improves the immunogenicity of Shigella flexneri type 2a O-specific polysaccharide-protein conjugates in mice

Seroepidemiological data and a clinical trial with a Shigella sonnei O-specific polysaccharide (O-SP)-Pseudomonas aeruginosa recombinant exoprotein A (rEPA) conjugate provide evidence that a critical level of immunoglobulin G (IgG) lipopolysaccharide (LPS) antibodies in serum confers protection against shigellosis. We evaluated the immunogenicity of conjugates whose carrier proteins and O-SPs were treated with succinic anhydride (SA), which reacts with amino groups at neutral pH to form amide-linked carboxyls (succinylation). Conjugates were synthesized with either of two genetically inactivated medically useful toxins, the diphtheria protein CRM9 or rEPA, bound to the O-SP of Shigella flexneri type 2a. Conjugates composed of the succinylated protein, succinylated O-SP, or both succinylated components were administered to mice by a clinically relevant scheme, and their levels of serum IgG anti-LPS and anti-proteins were assayed 7 days after the second and third injections. CRM9 served as a more immunogenic carrier than rEPA. Conjugates composed of succinylated components were more immunogenic than the conjugates composed of the native components. SA treatment of both the carrier protein and the O-SP did not confer an advantage over the succinylated protein alone. Conjugates prepared with native proteins, in general, elicited slightly higher levels of IgG protein antibodies than conjugates composed of the SA-treated proteins.

Comparative physical and genetic maps of the virulence plasmids of Salmonella enterica serovars typhimurium, enteritidis, choleraesuis, and dublin

Using fragment profiling, PCR, and Southern hybridization, we found that Salmonella enterica serovar Choleraesuis harbored virulence plasmids of various sizes, whereas serovars Typhimurium, Enteritidis, and Dublin carried a plasmid of a unique size. Also, the virulence plasmid of Typhimurium contained genes in the same order detected in the other three plasmids, all of which contained deletions.

Protein conjugates of synthetic saccharides elicit higher levels of serum IgG lipopolysaccharide antibodies in mice than do those of the O-specific polysaccharide from Shigella dysenteriae type 1

Our development of vaccines to prevent shigellosis is based on the hypothesis that a critical (protective) level of serum IgG to the O-specific polysaccharide (O-SP) domain of Shigella lipopolysaccharide (LPS) confers immunity. The O-SP is a hapten and must be conjugated to a protein to induce serum antibodies. The O-SP of Shigella dysenteriae type 1 (approximately 27 tetrasaccharide repeat units), prepared by acid hydrolysis of the LPS, was bound to human serum albumin (HSA) by multiple point attachment (O-SP-HSA): The molar ratio of HSA to O-SP was 1.0. Synthetic saccharides, composed of one or multiples of the O-SP tetrasaccharide, equipped with a spacer at their reducing end, were bound to HSA by a single point attachment: The average molar ratios of the saccharides to HSA ranged from 4 to 24. Serum IgG anti-LPS, elicited in mice by O-SP-HSA or synthetic tetra-, octa-, dodeca-, and hexadecasaccharide fragments, was measured by ELISA. Outbred 6-week-old female mice were injected s.c. three times at biweekly intervals with 2.5 micrograms of saccharide as a conjugate and were bled 7 days after the second and third injections. Excepting the tetramer, conjugates of the octamer, dodecamer and hexadecamer elicited IgG LPS antibodies after the second injection, a statistically significant rise (booster) after the third injection, and higher levels than those vaccinated with O-SP-HSA (P = 0.0001). The highest geometric mean levels of IgG anti-LPS were elicited by the hexadecamer with 9 chains or 9 moles of saccharide/HSA (15.5 ELISA units) followed by the octamer with 20 chains (11.1 ELISA units) and the dodecamer with 10 chains (9.52 ELISA units). Clinical evaluation of these synthetic saccharides bound to a medically useful carrier is planned.

Prognostic value of plasma HIV RNA in the natural history of Pneumocystis carinii pneumonia, cytomegalovirus and Mycobacterium avium complex. Multicenter AIDS Cohort Study

OBJECTIVES

To use follow-up on untreated HIV-positive men to assess the prognostic information provided by baseline data on plasma HIV RNA, CD4 cell count, age, and HIV-related symptom status, separately for three specific AIDS-defining illnesses: Pneumocystis carinii pneumonia (PCP), cytomegalovirus (CMV), and Mycobacterium avium complex (MAC).

METHODS

The study population were 734 HIV-positive homosexual men enrolled in the Multicenter AIDS Cohort Study, with follow-up (1984-1985 through mid-1988) restricted to the antiretroviral treatment-free and prophylaxis-free era. Baseline marker values were categorized and assessed as predictor variables in separate time-to-event analyses for each of the three specific outcomes.

RESULTS

A total of 138 cases of PCP, 25 cases of CMV, and 25 cases of MAC were observed. For PCP and CMV, higher categories of HIV RNA and lower categories of CD4 cell count were associated with increased risk relative to the respective reference groups. For MAC, oral candidiasis or fever and elevated HIV RNA at baseline were the primary risk factors. Further analysis highlighted the importance of monitoring HIV RNA levels in addition to CD4 cell counts when evaluating patients' risk of developing PCP.

CONCLUSIONS

In the absence of treatment, plasma HIV RNA levels provide prognostic information about the risk of these three specific AIDS-defining illnesses, independently of the CD4 cell count. These data provide a useful reference as researchers investigate changing patterns in the incidence and predictors of opportunistic infections in the era of increasingly active antiretroviral therapies.

Myocardial oxygenation during high work states in hearts with postinfarction remodeling

BACKGROUND

Postinfarction left ventricular remodeling (LVR) is associated with reductions in myocardial high-energy phosphate (HEP) levels, which are more severe in animals that develop overt congestive heart failure (CHF). During high work states, further HEP loss occurs, which suggests demand-induced ischemia. This study tested the hypothesis that inadequate myocyte oxygen availability is the basis for these HEP abnormalities.

METHODS AND RESULTS

Myocardial infarction was produced by left circumflex coronary artery ligation in swine. Studies were performed in 20 normal animals, 14 animals with compensated LVR, and 9 animals with CHF. Phosphocreatine (PCr)/ATP was determined with 31P NMR and deoxymyoglobin (Mb-delta) with 1H NMR in myocardium remote from the infarct. Basal PCr/ATP tended to be decreased in postinfarct hearts, and this was significant in animals with CHF. Infusion of dobutamine (20 microg x kg-1 x min-1 IV) caused doubling of the rate-pressure product in both normal and LVR hearts and resulted in comparable significant decreases of PCr/ATP in both groups. This decrease in PCr/ATP was not associated with detectable Mb-delta. In CHF hearts, rate-pressure product increased only 40% in response to dobutamine; this attenuated response also was not associated with detectable Mb-delta.

CONCLUSIONS

Thus, the decrease of PCr/ATP during dobutamine infusion is not the result of insufficient myocardial oxygen availability. Furthermore, in CHF hearts, the low basal PCr/ATP and the attenuated response to dobutamine occurred in the absence of myocardial hypoxia, indicating that the HEP and contractile abnormalities were not the result of insufficient oxygen availability.

Epitopic overload at the site of injection may result in suppression of the immune response to combined capsular polysaccharide conjugate vaccines

Capsular polysaccharide (CP) conjugate vaccines targeting a variety of bacterial infections are currently under development and clinical evaluation. The inclusion of multiple CP serotypes combined in a single injection is an important maneuver being evaluated. The combination of CP conjugate vaccines into a single multivalent injection may result in competition among the different components and adversely affect the immunogenicity of any individual conjugate. We observed a reduction of 30-90% in antibody responses to several serotypes in mice when immunogenicity of a 12-valent Escherichia coli (E. coli) lipopolysaccharide (LPS) conjugate vaccine was compared to the immunogenicity of each monovalent vaccine evaluated separately. A reduction of 30% was observed in the Staphylococcus aureus (S. aureus) type 8 CP antibodies when a type 8-rEPA conjugate was combined with a type 5-rEPA conjugate. S. aureus types 5 and 8-rEPA conjugates were combined with 100 micrograms of either rEPA (homologous) or diphtheria toxoid (DT) (heterologous) carrier proteins, and evaluated in rEPA or DT primed mice. The addition of the homologous protein resulted in a 64% reduction in type 5 CP antibodies. The heterologous protein did not affect the immunogenicity of the type 5. We postulate that the free protein competed with the conjugate and recruited most of the rEPA primed T cells. In the case of the DT conjugates, the DT targeted different populations of the T cells, thus interference was not observed. These data suggested that the epitopic load rather than the antigenic load at the site of injection caused reduced immunogenicity of the conjugates. We theorize that individual components of multivalent CP vaccines conjugated to the same carrier proteins would compete for a limited number of specific carrier protein primed T cells. This would result in one or more components being unavailable in eliciting a sufficient immune response. The use of multiple carrier proteins should be considered as an approach to reduce interference when multivalent conjugate vaccines are to be formulated into a single injection.

Molecular identification of a role for tyrosine 167 in the function of the human intestinal proton- coupled dipeptide transporter (hPepT1)

hPepT1 is a proton-coupled peptide transporter that mediates the absorption of di- and tripeptides. Here we show that tyrosine 167 (Y167) in transmembrane domain 5 (TMD5) of this 12-transmembrane spanning protein contributes to its transport function. We identified this particular amino acid by a computer model of the arrangement of the TMDs of hPepT1 and investigated its role by site-directed mutagenesis and dipeptide uptake studies. [3H]Gly-sar uptake in cells transiently transfected with Y167A-hPepT1 was abolished completely, even though the level of Y167A-hPepT1 expression by Western blot analysis and cell surface expression by immunofluorescence microscopy was similar to those of the wild type. Therefore, mutation affected transport function, but apparently not the steady-state protein level or trafficking of the transporter to the plasma membrane. Moreover, mutation of Y167 into phenylalanine, serine, or histidine all abolished gly-sar uptake in transfected HEK 293 cells. Taken together, these findings suggest that Y167 plays an essential role in hPepT1 function, perhaps due to the unique chemistry of its phenolic side chain.

Decline in total T cell count is associated with onset of AIDS, independent of CD4(+) lymphocyte count: implications for AIDS pathogenesis

We previously reported that blind T cell homeostasis, in which the total T cell count is maintained but the CD4(+) and CD8(+) subset composition of the T cells can vary, fails approximately 1.5 to 2.5 years before the onset of AIDS. The present study was premised on the hypothesis that if failure of T cell homeostasis (i.e., a decline in total T cell counts) is important in the pathogenesis of AIDS, it should be a significant predictor of AIDS after controlling for the CD4(+) lymphocyte count. Data from 1556 homosexual men with sufficient sequential T cell subset measurements were evaluated, representing 11,988 person-visits in men with known clinical outcomes over a period of more than 10 years. Using regression models that incorporated CD4(+) lymphocyte count and HIV-related symptoms (fever, thrush), it was determined that a yearly decline of more than 300 T cells/microliter of peripheral blood was an independent predictor of the onset of AIDS for subjects with CD4(+) lymphocyte counts of <500 cells/microliter. The results support an important role for failure of T cell homeostasis in the pathogenesis of AIDS.