Comparison of Western immunoblots and gene detection assays for identification of potentially enterotoxigenic isolates of Clostridium perfringens

Clostridium perfringens enterotoxin (CPE) is an important sporulation-associated virulence factor in several illnesses of humans and domestic animals, including C. perfringens type A food poisoning. Therefore, the ability to determine the enterotoxigenicity of food or fecal C. perfringens isolates with simple, rapid assays should be helpful for epidemiologic investigations. In this study, Western immunoblotting (to detect CPE production in vitro) was compared with PCR assays and digoxigenin-labeled probe assays (to detect all or part of the cpe gene) as a method for determining the enterotoxigenicity of C. perfringens isolates. The cpe detection assays yielded reliable results with DNA purified from vegetative C. perfringens cultures, while Western immunoblots required in vitro sporulation of C. perfringens isolates to detect CPE production. Several cpe-positive C. perfringens isolates from diarrheic animals did not sporulate in vitro under commonly used sporulation-inducing conditions and consequently tested CPE negative. This result indicates that cpe gene detection and serologic CPE assays do not necessarily yield similar conclusions about the enterotoxigenicity of a C. perfringens isolate. Until further studies resolve whether these cpe-positive isolates which do not sporulate in vitro can or cannot sporulate and produce CPE in vivo, it may be preferable to use cpe detection assays for evaluating C. perfringens isolate enterotoxigenicity and thereby avoid potential false-negative conclusions which may occur with serologic assays.

Management of ipsilateral supracondylar femur fractures following total knee arthroplasty

A complete review of the literature revealed 195 fractures in 12 published studies of ipsilateral supracondylar femur fractures occurring about a total knee arthroplasty. This review included general surveys, multicenter studies, and case reports. Based on these studies, the authors divided the fractures into nonoperative and operative treatment groups. The fracture types were also subclassified into nondisplaced (Neer type 1) and displaced (Neer types 2 and 3). Statistical analysis of each type of fracture in terms of the various treatments and clinical outcome was performed. This study revealed satisfactory results in 83% of the patients with nondisplaced fractures that were treated without surgery. In contrast, 64% of all patients with displaced fractures that were treated with or without surgery had satisfactory outcomes. This difference is statistically significant (P < .05). Of the patients with displaced fractures, nonoperative versus operative results were not statistically significant (P < .9) (67% satisfactory vs 61%). A treatment algorithm is proposed based on the above data.

Expression of Ki67 antigen, epidermal growth factor receptor and Epstein-Barr virus-encoded latent membrane protein (LMP1) in nasopharyngeal carcinoma

The expression of Ki67 antigen, epidermal growth factor receptor (EGFR) and the Epstein-Barr virus (EBV)-encoded latent membrane protein (LMP1) in nasopharyngeal carcinoma (NPC) was immunohistochemically determined. In cases with sufficient material western blot analysis was applied to analyse the LMP1 expression. Biopsies from 20 Chinese and 3 Swedish patients with NPC were included in the study. Our results demonstrated a nuclear Ki67 staining, a membrane EGFR staining, and a dot-like cytoplasmic and/or membrane LMP1 staining pattern in tumour cells of NPC. The proportion of Ki67-positive cells correlated with tumour stage. A strong expression of EGFR was frequently seen in patients with tumour stages III and IV and was paralleled by a higher proportion of Ki67-positive cells. The majority of the LMP1-positive cases strongly expressed EGFR and had a higher proportion of Ki67-positive cells, indicating a possible effect of EBV LMP1 on the proliferation of tumour cells in NPC. The increased expression of EGFR and Ki67 in NPC at late tumour stage indicates their possible use in malignancy grading of NPC.

Inhibitory effects of chlorpheniramine and astemizolum on contraction of isolated rat and rabbit uteri induced by oxytocin and PGF2 alpha

The contraction of isolated rat and rabbit uteri induced by oxytocin and PGF2 alpha was markedly inhibited by chlorpheniramine (Chl) and astemizolum (Ast), both of which also decreased the resting tension of uteri, and their spontaneous contraction. The inhibitory effects of both drugs were dose-dependent. At high concentrations, Chl 7.4 x 10(-4) mol/L and Ast 10(-4) mol/L could counteract the contraction of the uteri induced by Oxy and PGF2 alpha, and their spontaneous contraction as well. They decreased the resting tension to the lower level. The mechanism of their non-special relaxed action on uteri could not be completely explained only by their H1-receptor blocking action. Whether they act by blocking calcium channel or by inhibiting calmodulin (CaM) remains to be further explored.

Iteration algorithm for computer-aided speckle interferometry

An iteration algorithm for the analysis of speckle interference patterns is presented. First, four digitized phase-shifted patterns are locally averaged. The phase information is then extracted by the usual phase shift algorithm. The wrapped phase is in turn used to reconstruct four new phase-shifted patterns. These three steps form a cycle. Repetition of the three steps has a great effect on suppressing speckle noise. Theoretical study shows that the iterated phase converges to a perfect result under ideal conditions. In general, the iteration causes little error but improves the phase information a great deal. The signal-to-noise ratio rises when additional iterations are performed.

Characterization of cell lines that inducibly express the adeno-associated virus Rep proteins

The replication (rep) gene of adeno-associated virus (AAV) is involved in AAV DNA replication, gene regulation, and inhibition of cellular transformation induced by various oncogenes. To study the rep gene's antiproliferative effects, we have developed cell lines which express the replication proteins under the control of an inducible mouse metallothionein transcription promoter. The Rep78 protein produced in these cell lines binds to the AAV terminal repeat sequences in vitro and supports AAV DNA replication and trans activation of the AAV p40 transcription promoter in vivo. These cell lines are capable of assembling infectious viruses containing a mutant rep gene or a vector bearing a heterologous gene. Growth rate and colony formation efficiency assays indicated that rep gene expression substantially altered cellular proliferation. Long-term induction of the cell lines followed by removal of the inducing agent suggested that constitutive expression of the Rep proteins does not necessarily result in cell death and that the cells can recover from the cytostatic effects. Flow cytometry analysis indicated that the presence of the Rep proteins increased the population of cells in the S phase of the cell cycle. Thus the rep gene's antiproliferative effects may be realized by interference with cellular DNA replication.

Management of tibial defects in total knee arthroplasty. A biomechanical study

Peripheral deficiencies of tibial bone stock must be appropriately addressed at total knee arthroplasty to help ensure stability of the tibial component. Conversion of the oblique shaped peripheral defects into defects with vertical and horizontal surfaces, before repair, should lead to improved stability of tibial component fixation. In vitro testing revealed that conversion of the oblique wedge defect into a stepped pattern resulted in improved rigidity of the system when testing five specimens with a 20 degrees peripheral defect (wedge stiffness 25.5 +/- 1.08 versus step stiffness 32.4 +/- 1.72; p < 0.01) and five specimens with a 35 degrees defect (wedge stiffness 18.7 +/- 0.74 versus step stiffness 25.6 +/- 0.85; p < 0.0001). Improved rigidity of the system was further illustrated when a fibrous interface was introduced between the bone and cement surfaces (wedge stiffness 4.8 +/- 0.6 versus step stiffness 29.9 +/- 1.4; p < 0.0001). One hundred percent of wedge shaped cement constructs failed and slipped off, while none of the step shaped constructs described herein failed at the cement to bone interface. There were no statistically significant differences in stiffness with the incorporation of a metal wedge or block into the system when compared with the cement repaired stepped pattern. These biomechanical studies suggest that alterations in the configuration of peripheral defects can create a more rigid system that should ultimately result in improved support to the tibial component overlying these defects.

Excessive production of insulin-like growth factor-I by silicotic rat alveolar macrophages

The supernatant of silicotic rat alveolar macrophages can stimulate fibroblast growth. The present study demonstrates that this activity is mainly attributed to insulin-like growth factor-I. Partial purification of the supernatant of alveolar macrophages, which were from silica-exposed 5 to 6-week-old rats, revealed a protein peak (peak 5) eluted from a molecular-sieve HPLC column, corresponding to a MW of 6-9 kDa. Activity assay and radioimmunoassay indicated that this peak is more potent with regard to stimulation of fibroblast growth and has higher insulin-like growth factor-I immunoreactivity, but there was no detectable activity of interleukin-1 or tumor necrosis factor. Quantification of insulin-like growth factor-I also manifests elevated insulin-like growth factor-I levels in silicotic rat bronchoalveolar lavage fluids which tend to increase with prolongation of silica exposure in vivo, but no alteration in insulin-like growth factor-I level can be found in sera. These findings suggest that excessive production of insulin-like growth factor-I by alveolar macrophages locally may play a pivotal role in silica-induced pulmonary interstitial fibrosis.

Sequence and position requirements for uridylate-rich downstream elements of polyadenylation signals

We have defined the positional and sequence requirements of U-rich downstream elements using a simian virus 40 late polyadenylation signal containing a substituted downstream region. A UUUUU element will significantly increase the efficiency of 3' end processing when placed between 6 and 25 bases downstream from the cleavage site. Positions in this interval closer than 15 bases from the cleavage site, however, were noticeably less efficient. Placement of the UUUUU element between +20 and +25 caused a partial shift in cleavage site usage to a CA motif at +4. Mutational analysis indicated that the sequence requirements at individual positions of the UUUUU element were somewhat flexible. Changing more than one base of the UUUUU sequence, however, severely diminished the ability of the element to mediate efficient 3' end processing. Finally, although hnRNP C proteins specifically interact with U-rich sequences, this protein--RNA interaction is not required for efficient in vitro polyadenylation.

[Experimental study of the evaluation of efficacy of fluid replacement based on Parkland formula for burn shock]

In order to investigate the effect of fluid resuscitation of burn shock according to Parkland formula and to find out whether it leaves any damage due to hypoxia, 22 male mongrel dogs with 50% III degrees burn were divided randomly into two groups. Group 1 (14 dogs) received no fluid replacement, whereas in group 2 (8 dogs) Ringer's lactate solution was given according to Parkland formula after the injury. Swan-Ganz catheter was inserted to the pulmonary artery before burn. FAP, CVP, PAP, cardiac output and blood gas analysis were measured preburn and at 2, 6, 12, 18, 24, 36 and 48 hours postburn. The results demonstrated that group 1 dogs all died within 12 hours postburn and group 2 dogs all survived over the shock period. However, even in these survived dogs, markedly decreased cardiac output and oxygen consumption were observed over the first 18 hours postburn. This indicated that fluid replacement according to Parkland formula can not completely correct the inadequacy of tissue perfusion, and it may leave certain damage of oxygen deficiency. Therefore, further improvement in fluid resuscitation and combined treatment for early burn shock to raise cardiac output and improve tissue oxygen delivery may be needed.

[On the method of hyperthermic chemotherapy by regional isolated perfusion for tumors of lower extremities]

From August 1990 to June 1993, 30 patients with osteosarcoma of lower extremities were treated with chemotherapy by hyperthermic regional isolated perfusion. There were 19 male and 11 female with a mean age of 21 (15-28) years. All of the tumors were located in the lower limbs: 20 on the femora, 9 on the tibiae and 1 on the fibula. Chemotherapy was going on for 60 minutes during hyperthermic regional isolated perfusion. Temperature was kept at 42 degrees C in deep soft tissue around the tumor during perfusion. The results showed that local edema of the limbs were reduced observably, tumors were shrunken and hardened after perfusion. Perimeter of the limbs were decreased and mobility of the limbs increased. Pathological examination indicated that all of the tumors responded well to the chemotherapy by perfusion and 90%-95% of the osteosarcoma cells were destroyed. Two cases were complicated with compression syndrome, and 1 with renal failure. The authors would suggest that hyperthermic regional isolated perfusion is an effective chemotherapeutic method in management of malignant tumors of limbs.

14-3-3 proteins bind to histone and affect both histone phosphorylation and dephosphorylation

14-3-3 proteins appear to play a critical role in Ca(2+)-stimulated secretion in permeabilized chromaffin cells. 14-3-3 proteins have been reported to be both stimulators and inhibitors of protein kinase C (PKC). We have found that 14-3-3 proteins, isolated on the basis of their ability to enhance secretory activity, stimulated histone phosphorylation by PKC, but they had no effect on myosin light chain phosphorylation by PKC. 14-3-3 proteins were also found to inhibit the rate of [32P]histone dephosphorylation but not the rate of [32P]myosin light chain dephosphorylation. Cross-linking experiments and affinity chromatography demonstrated that 14-3-3 proteins bind to histones. These results suggest that at least some of the reported effects of 14-3-3 proteins on PKC activity may result from 14-3-3 proteins binding to histone.

Colonoscopic follow-up of colorectal carcinoma

PURPOSE

The value of routine colonoscopy in the prevention or early detection of metachronous carcinoma of the colon and rectum remains unproven. This study attempts to clarify this issue.

METHODS

An analysis of a personal series of 460 patients with primary colorectal carcinoma treated by the second author between 1972 and 1990 was reviewed. After various exclusions, there remained 231 patients who had been prospectively followed by colonoscopy with a mean follow-up period of 5.6 years.

RESULTS

In 48 (21 percent) patients, there were synchronous adenomas present at the time of the initial resection for carcinoma and 35 (73 percent) of these patients subsequently developed metachronous adenomas, being recurrent in 22. Ninety-five (52 percent) of the 183 patients without synchronous adenomas eventually developed metachronous adenomas, so that overall 130 (56 percent) patients developed a metachronous adenomas. Four patients developed a metachronous carcinoma that was either Dukes A or B, and all remain well at the time of final follow-up. These metachronous carcinomas were found after a mean interval of seven and three-quarter years. All four patients had synchronous adenomas and all developed metachronous adenomas on multiple occasions before the metachronous carcinoma was detected. Thus, a subset consisting of only 22 patients produced all four metachronous malignancies--a rate of 18 percent.

CONCLUSION

It would appear that the presence of synchronous adenomas with the subsequent development of recurring metachronous adenomas is significant and warrants a more intensive follow-up program to ensure the early diagnosis and more likely cure of any metachronous carcinoma.

Identification and characterization of cDNA clones encoding plant calreticulin in barley

Two cDNA clones (CRH1 and CRH2) homologous to animal calreticulin, a major calcium storage protein in the lumen of the endoplasmic reticulum, were isolated from an ovary cDNA library of barley through differential screening. The two clones differ in the 3' untranslated region and the 5' region that encodes a putative N-terminal signal sequence. CRH1 was mapped to the minus arm of chromosome 1. CRH2 was mapped to the minus arm of chromosome 2. The deduced amino acid sequences share 50 to 55% identity with animal calreticulins and exhibit the same three-zone characteristic. Recombinant protein stained blue with Stains-all and bound 45Ca2+ when transferred to nitrocellulose membranes. A native protein of approximately 55 kD was identified in ovary extract. Elevated gene expression was observed in ovaries 1 day after pollination and during early embryogenesis. CRH1 was expressed at a higher level than CRH2. These studies demonstrate the presence of calreticulin in plant cells and its developmental regulation in fertilization.

Differences in stage at presentation of breast and gynecologic cancers among whites, blacks, and Hispanics

BACKGROUND

One of the possible assumptions for the higher mortality from cancer of blacks versus whites is that blacks tend to be diagnosed relatively more often with later stage disease. This study examined the stages at diagnosis for female breast cancer and other gynecologic cancers among blacks, non-Hispanic whites, and Hispanic whites.

METHODS

Data for Dade County were analyzed in this study, which was based on the tumor registry data from the Florida Cancer Data System from 1981-1989. The stages at diagnosis were classified as in situ, local, regional, and distant according to the International Classification of Diseases for Oncology coding rules.

RESULTS

The percentage of early stage diagnoses (in situ and local stage) was significantly lower among blacks and Hispanic whites than among non-Hispanic whites, but only for breast and cervical cancer. There was a significant increase in the percentage of early stage diagnoses of breast cancer among all three groups during 1981-1989, whereas this increase was found only in Hispanic whites for cervical cancer. The percentage of in situ cervical cancers was much lower in women older than age 45, especially among women older than age 65, in all three groups.

CONCLUSIONS

These data suggest that screening programs need to be targeted differently for specific age and ethnic groups.

Effect of beta-lymphocyte- and NPC-derived EBV-LMP1 gene expression on in vitro growth and differentiation of human epithelial cells

The effect of expression of the Epstein-Barr-virus (EBV) latent membrane protein (LMP1) derived from B-lymphocytes (B) and nasopharyngeal carcinoma (NPC) (C) on the in vitro growth and differentiation of a human keratinocyte line, Rhek-1, was analyzed in clonal growth and in in vitro differentiation assays. In contrast to the polygonal parental cells, the B-LMP1-expressing sublines were spindle-shaped while the C-LMP1-expressing cells were pleomorphic. Both B- and C-LMP1-expressing sublines showed increased proliferation as evidenced by: (1) higher colony-forming efficiency (CFE) and larger colony size at reduced serum levels; (2) an increased number of epithelial cell layers formed in the air-liquid-interface culture system and (3) increased expression of proliferative cell nuclear antigen (PCNA). At low serum concentration, the C-LMP1-expressing sublines formed larger colonies than those expressing B-LMP1. In the air-liquid-interface culture system, both B- and C-LMP1-expressing lines showed reduced epithelial differentiation resulting in reduced stratification and reduced involucrin expression similar to those of the cancer cell line, Siha. The results of the present study indicate that the expression of LMP1 in human keratinocytes is associated with morphological transformation and predisposes these cells to a more neoplastic phenotype. The structural difference between the 2 genes responsible for the functional differences and transforming ability will be pinpointed in further experiments.

Cancer in south Florida Hispanic women. A 9-year assessment

BACKGROUND

Cancer incidence varies among race and ethnic subgroups. Relatively little information exists on cancer among Hispanics, and none of it it stratified by race.

METHODS

To explore and compare cancer incidence rates of each site of cancer among white Hispanic, white non-Hispanic, black Hispanic, and black non-Hispanic women in Dade County, South Florida, we accessed 9 years of cancer incidence data. Dade County's Hispanic population is the second largest of any US county. For each site, incidence rates, rate ratios, and 95% confidence intervals are presented.

RESULTS

Among white Hispanics, there were statistically significant lower rates of cancers of the oral cavity, esophagus, colon, pancreas, lung, breast, ovary, bladder, kidney, melanoma, Kaposi's sarcoma, and non-Hodgkin's lymphoma than among white non-Hispanics. Black Hispanics had significantly lower rates of cancers of the oral cavity, stomach, rectum, lung, cervix, and bladder than black non-Hispanics. However, white Hispanic women had significantly higher rates of cancers of the liver, gallbladder, and uterine cervix than white non-Hispanic women. No in situ breast cancer cases among blacks of either ethnic subgroup was found.

CONCLUSION

Both white Hispanic and black Hispanic women generally had lower rates of cancer than their race-specific non-Hispanic counterparts. However, incidence rates among Hispanics differ substantially by race; failure to distinguish them may lead to erroneous conclusions.