Patterns of endoscopic follow-up after surgery for nonmetastatic colorectal cancer

BACKGROUND

Endoscopic examinations of the colon are often recommended for surveillance following colorectal cancer resection. The actual use and outcome of this testing are not known.

METHODS

Five thousand seven hundred sixteen patients 65 years of age or older with local or regional stage colorectal cancer diagnosed in 1991 were identified through the Surveillance Epidemiology and End Results registry. All inpatient and outpatient Medicare claims from 6 months after diagnosis through the end of 1994 were examined to determine use of endoscopic procedures.

RESULTS

One or more colonoscopies were performed in 51%, with an average of 2.9 procedures performed among those tested; sigmoidoscopy was performed in 17%. The rate of colonoscopy was highest during the initial 18 months. Polypectomy was performed in 21% of all patients, and subsequent primary colorectal tumors were diagnosed in 1.3%. Factors associated with colonoscopy and sigmoidoscopy use included younger age, survival through follow-up, and geographic region; sigmoidoscopy was also more common in relation to rectal cancers.

CONCLUSIONS

There is variability in the use of endoscopic procedures following potentially curative resection for colorectal cancer, with patient-related factors and local practice patterns accounting for the variation. Further studies are needed to elicit the reasons for lack of follow-up and adherence to practice guidelines.

[A study on the determination method of biological function of BRF]

This study was aimed to establish a method for determining the biological function of biological wave regulating factor (BRF). Proteus mirabilis was used to set up the experimental model. The biological function of the component obtained from wave growth media beneath the bacterial colony rings resulting from bacterial proliferation was determined in biological wave test by analytically microbiological method. The results indicated that BRF could enhance biological wave and shorten its period. The method is of some value in studying the regulative mechanism of biological wave.

Coexpression of cyt1Aa of Bacillus thuringiensis subsp. israelensis with Bacillus sphaericus binary toxin gene in acrystalliferous strain of B. thuringiensis

The cyt1Aa gene of Bacillus thuringiensis subsp. israelensis and binary toxin gene of Bacillus sphaericus C3-41 were introduced into an acrystalliferous strain of B. thuringiensis independently and in combination by using shuttle vector pBU4. SDS-PAGE and Western blot analysis proved that cyt1Aa and binary toxin genes coexpressed during the sporulation of the recombinant. Transformant strain expressing the Cyt1Aa and binary toxin proteins in combination was more toxic to susceptible and resistant Culex pipiens quinquefasciatus than the transformants expressing Cyt1Aa protein or binary toxin proteins independently. It was suggested that large amount of production of Cyt1Aa protein and binary toxin proteins possibly interacted synergistically, thereby increasing its mosquitocidal toxicity significantly.

Agreement of Medicare claims and tumor registry data for assessment of cancer-related treatment

BACKGROUND

Although health claims data are increasingly used in evaluating variations in patterns of cancer care and outcomes, little is known about the comparability of these data with tumor registry information.

OBJECTIVES

To evaluate the agreement between Medicare claims and tumor registry data in measuring patterns of diagnostic and therapeutic procedures for older cancer patients.

RESEARCH DESIGN

Analysis of a database linking Surveillance, Epidemiology and End Results (SEER) registry data and Medicare claims in patients aged > or =65 years with cancer.

SUBJECTS

361,255 Medicare patients with invasive breast, colorectal, endometrial, lung, pancreatic, and prostate cancer diagnosed between 1984 and 1993.

MEASURES

Concordance of SEER files with corresponding Medicare claims.

RESULTS

Medicare claims generally identified patients who underwent resection and radical surgery according to SEER (ie, concordance > or =85%-90%) but less likely biopsy or local excision (ie, concordance < or =50%). In some instances, claims also categorized patients as having more invasive surgery than was listed in SEER and also provided incremental information about the use of surgical treatment after 4 months. SEER files and, to a lesser degree, Medicare claims identified radiation therapy not included in the other data source, and Medicare files also captured a significant number of patients with codes for chemotherapy.

CONCLUSIONS

Medicare files may be appropriate for studies of patterns of use of surgical treatment, but not for diagnostic procedures. The potential benefit of Medicare claims in identifying delayed surgical intervention and chemotherapy deserves further study.

[Exploration of the mechanism of skin expansion]

OBJECTIVE

In order to explore the mechanism of skin expansion technique (SET).

METHODS

Domestic dogs were used in this experiment. The epidermal mitotic activity, capillary blood flow change of the expanded flap were observed with microspectrophotometer and radioactive microsphere technique.

RESULTS

1. The epidermis of expanded skin was significantly thicker than that of other groups (P < 0.05). 2. The epidermal mitotic activity was elevated significantly(P < 0.01). 3. The capillary blood flow of expanded flaps increased significantly (P < 0.01).

CONCLUSIONS

1. The surplus skin produced by SET is the result of replication, not compensation. 2. SET increases skin blood flow, therefore enlarges the survival area of an expanded flap.

Quality of life for children with fecal incontinence after surgically corrected anorectal malformation

PURPOSE

The aim of this study was to investigate influences of fecal incontinence on children's quality of life after surgically corrected anorectal malformation.

METHODS

Seventy-one children with anorectal malformation underwent follow-up for 8 to 16 years postoperatively. They were divided into good, fair, and poor groups by assessment of anal function. The quality of life was investigated by self-structured disease impact questionnaires and Achenbach's Child Behavior Check List (CBCL). A quality-of-life scoring criteria was established to assess quality of life of the 71 children with operated anorectal malformation and controls.

RESULTS

Owing to fecal incontinence, 12 (16.9%) children reported that there were problems in peer relationships; school absences happened in 13 (18.3%) children; 17 (23.9%) children had to restrict themselves to certain food. Based on CBCL, 13 (18.3%) children had behavior problems. The behavior problems in children with poor fecal continence (66.7%) were significantly higher than those of children with good fecal continence (8.6%). According to the quality-of-life scoring criteria, the scores of children with operated anorectal malformation (9.4+/-3.7) were significantly lower than those of the controls (11.2+/-0.9). The scores of children with poor fecal continence (4.8+/-1.4) were significantly lower than those of children with good fecal continence (10.9+/-1.2).

CONCLUSIONS

The children with poor fecal continence have poor quality of life caused by fecal dysfunction. Attention should be paid to the rehabilitation of fecal continence after surgery, such as bowel training and biofeedback therapy. The somatic and psychological care and long-term follow-up are necessary to improve the quality of life.

Actinonin, a naturally occurring antibacterial agent, is a potent deformylase inhibitor

Peptide deformylase (PDF) is essential in prokaryotes and absent in mammalian cells, thus making it an attractive target for the discovery of novel antibiotics. We have identified actinonin, a naturally occurring antibacterial agent, as a potent PDF inhibitor. The dissociation constant for this compound was 0.3 x 10(-)(9) M against Ni-PDF from Escherichia coli; the PDF from Staphylococcus aureus gave a similar value. Microbiological evaluation revealed that actinonin is a bacteriostatic agent with activity against Gram-positive and fastidious Gram-negative microorganisms. The PDF gene, def, was placed under control of P(BAD) in E. coli tolC, permitting regulation of PDF expression levels in the cell by varying the external arabinose concentration. The susceptibility of this strain to actinonin increases with decreased levels of PDF expression, indicating that actinonin inhibits bacterial growth by targeting this enzyme. Actinonin provides an excellent starting point from which to derive a more potent PDF inhibitor that has a broader spectrum of antibacterial activity.

How good is prediction of protein structural class by the component-coupled method?

Proteins of known structures are usually classified into four structural classes: all-alpha, all-beta, alpha+beta, and alpha/beta type of proteins. A number of methods to predicting the structural class of a protein based on its amino acid composition have been developed during the past few years. Recently, a component-coupled method was developed for predicting protein structural class according to amino acid composition. This method is based on the least Mahalanobis distance principle, and yields much better predicted results in comparison with the previous methods. However, the success rates reported for structural class prediction by different investigators are contradictory. The highest reported accuracies by this method are near 100%, but the lowest one is only about 60%. The goal of this study is to resolve this paradox and to determine the possible upper limit of prediction rate for structural classes. In this paper, based on the normality assumption and the Bayes decision rule for minimum error, a new method is proposed for predicting the structural class of a protein according to its amino acid composition. The detailed theoretical analysis indicates that if the four protein folding classes are governed by the normal distributions, the present method will yield the optimum predictive result in a statistical sense. A non-redundant data set of 1,189 protein domains is used to evaluate the performance of the new method. Our results demonstrate that 60% correctness is the upper limit for a 4-type class prediction from amino acid composition alone for an unknown query protein. The apparent relatively high accuracy level (more than 90%) attained in the previous studies was due to the preselection of test sets, which may not be adequately representative of all unrelated proteins.

The N-terminal domain of p73 interacts with the CH1 domain of p300/CREB binding protein and mediates transcriptional activation and apoptosis

The newly identified p53 homolog p73 mimics the transcriptional function of p53. We have investigated the regulation of p73's transcriptional activity by p300/CREB binding protein (CBP). p73-p300 complexes were identified in HeLa cell extracts by cofractionation and coimmunoprecipitation assays. The p73-p300 interaction was confirmed in vitro by glutathione S-transferase-protein association assays and in vivo by coimmunoprecipitating the overexpressed p300 and p73 in human p53-free small-cell lung carcinoma H1299 or osteosarcoma Saos-2 cells. The N terminus but not the N-terminal truncation of p73 bound to the CH1 domain (amino acids [aa] 350 to 450) of p300/CBP. Accordingly, this p73 N-terminal deletion was unable to activate transcription or to induce apoptosis. Overexpression of either p300 or CBP stimulated transcription mediated by p73 but not its N-terminally deleted mutant in vivo. The N-terminal fragment from aa 19 to 597, but not the truncated fragment from aa 242 to 1700 of p300, reduced p73-mediated transcription markedly. p73-dependent transcription or apoptosis was partially impaired in either p300- or CBP-deficient human breast carcinoma MCF-7 or H1299 cells, suggesting that both coactivators mediate transcription by p73 in cells. These results demonstrate that the N terminus of p73 directly interacts with the N-terminal CH1 domain of p300/CBP to activate transcription.

The association between hospital type and mortality and length of stay: a study of 16.9 million hospitalized Medicare beneficiaries

OBJECTIVES

To examine the association between hospital type and mortality and length of stay using hospitalized Medicare beneficiaries for a 10-year period.

METHODS

The retrospective cohort study included 16.9 million hospitalized Medicare beneficiaries > or = 65 years of age admitted for 10 common medical conditions and 10 common surgical procedures from 1984 to 1993. A total of 5,127 acute-care hospitals in the United States were grouped into 6 mutually exclusive hospital types based on teaching status and financial structure (for-profit [FP], not-for-profit [NFP], osteopathic [OSTEO], public [PUB], teaching not-for-profit [TNFP], and teaching public [TPUB]) as reported in the 1988 American Hospital Association database. Logistic and linear regression methods were used to examine risk-adjusted 30-day and 6-month mortality and length of stay.

RESULTS

During the 10-year study period, 10.6 million patients were admitted with 1 of the 10 selected medical conditions, and 6.3 million patients were hospitalized for 1 of the 10 selected surgical procedures. Patients at TNFP hospitals had significantly lower risk-adjusted 30-day mortality rates than patients at other hospital types when all diagnoses or procedures were combined (combined diagnoses: RR(TNFP) = 1.00 [reference], RR(TPUB) = 1.40, RR(OSTEO) = 1.14, RR(PUB) = 1.07, RR(FP) = 1.03, RR(NFP) = 1.02; combined procedures: RR(TNFP) = 1.00 [reference], RR(OSTEO) = 1.36, RR(TPUB) = 1.30, RR(PUB) = 1.16, RR(FP) = 1.13, RR(NFP) = 1.08). The results were mostly consistent when diagnoses and procedures were examined separately. After adjustment for patient characteristics, patients at other hospital types had 10% to 20% shorter lengths of stay (LOS) than patients at TNFP hospitals for most diagnoses and procedures studied.

CONCLUSION

As measured by the risk-adjusted 30-day mortality, TNFP hospitals had an overall better performance than other hospital types. However, patients at TNFP hospitals had relatively longer LOS than patients at other hospital types, perhaps reflecting the medical education and research activities found at teaching institutions. Future research should examine the empirical evidence to help elucidate the adequate LOS for a given condition or procedure while maintaining the quality of care.

[Neural electrophysiological observations on the external anal sphincter in patients with anorectal malformation]

OBJECTIVE

To explore the functional damage of the nerves controlling external anal sphincter in patients with congenital anorectal malformation and to design a new method for measuring the conductive time of sacral spinal center in the pudendo-anal reflex arc.

METHODS

45 patients with anorectal malformation and 20 normal subjects were subjected to detect the latency for pudendo-anal reflex, spinal-anal response and evoked potential of caude equine simultaneously. The conduction time of afferent motor nerve, efferent sense nerve and sacral spinal center in the pudendo-anal reflex arc were quantitatively analyzed.

RESULTS

The normal latency for pudendo-anal reflex was 23.3 +/- 6.9 ms, for spinal-anal response was 4.6 +/- 1.9 ms, and for evoked potential of caude equine was 3.8 +/- 0.9 ms. The conduction time of sacral spinal center was 14.8 +/- 6.6 ms. In patients with anorectal malformation, the latencies were prolonged obviously, especially the conduction time of sacral spinal center. There was a significant negative correlation between the latency and clinical scores. The correlation coefficient for pudendo-anal reflex was -0.68, for spinal-anal response was -0.64, and for conduction time of sacral spinal center was -0.60.

CONCLUSIONS

The abnormality of nerves serving anal sphincters was one of the important causes for postoperative fecal incontinence. The neural lesions are specially serious in the sacral spinal center.

On-line estimation of the maximum specific growth rate of nitrifiers in activated sludge systems

The on-line estimation of the maximum specific growth rate of autotrophic biomass is addressed in this article. A general nitrification process model, which is valid for any realistic flow pattern, is used to develop the estimation algorithm. Depending on the measurements available, two estimation equations are derived. While both require measuring the nitrification activity of the activated sludge, one requires the additional measurement of the nitrifiable nitrogen concentrations at the two ends of the bioreactor, and the other requires the nitrate nitrogen concentrations at the same locations. The algorithm also requires some stoichiometric and kinetic parameters. However, sensitivity analysis shows that the estimate is insensitive to the parameters other than the autotrophic decay rate. Compared to the existing algorithms, the algorithm developed in this article does not rely on the assumption of ideal flow pattern in the plant and does not require an error-prone estimate of the autotrophic biomass concentration. Experimental and simulation studies show that the algorithm performs well and is robust to influent variations and accidental sludge losses.

Colorectal carcinoma screening attitudes and practices among primary care physicians in counties at extremes of either high or low cancer case-fatality

BACKGROUND

To the authors' knowledge, physician attitudes and reported practices regarding colorectal carcinoma screening have not been studied in areas of highest risk for cancer death.

METHODS

Medicare claims were used to calculate colorectal carcinoma 2-year case-fatality rates for counties with >100 incident cases of colorectal carcinoma between 1991-1993. All 2682 practicing primary care physicians in 20 counties with the lowest case-fatality rates (mean of 29.9%) and 19 counties with the highest case-fatality rates (mean of 47.8%) were surveyed regarding their screening procedures and attitudes.

RESULTS

Among the 972 respondents (36.1%), the reported use of fecal occult blood testing (FOBT) and flexible sigmoidoscopy was similar in the low and high case-fatality counties. However, physicians who practiced in the high case-fatality counties were less likely to be trained in and to perform sigmoidoscopy themselves (37.0% vs. 45.6%; P<0.01). Moreover, practitioners in the high case-fatality counties were more likely than the other physicians to consider or plan enhanced FOBT and sigmoidoscopic screening in the near future. FOBT and sigmoidoscopy screening rates at the county level were associated negatively with cancer incidence rates, case-fatality rates, and metastatic disease rates, suggesting a potentially protective effect.

CONCLUSIONS

Geographically targeted interventions are a potentially cost-effective strategy for focusing additional screening services on the highest risk populations. The primary care clinicians in these high risk areas are logical partners for these interventions by virtue of their high degree of readiness to change their current screening practices.

[Combined use of rhBMP2/BCB and free periosteum in repairing segmental defects in radii of rabbits]

OBJECTIVE

To study the efficacy of combined use of rhBMP2/BCBand free periosteal graft in repairing segmental bony defects.

METHODS

A new grafting material (rhBMP2/BCB) was made by combining recombinant human BMP2 (rhBMP2) and an antigen-free bovine cancellous bone (BCB) as a carrier. rhBMP2/BCB was used alone in conjunction with free periosteal graft to repair a 1.5 cm defect in the radius of the rabbit. The defect-repairing capability for each of the treatment modalities was assessed radiographically, biomechanically, and by densitometry and histological studies.

RESULTS

rhBMP2/BCB used alone was capable of healing the defect in large by 16 weeks, with a similar repair process and mechanism seen with RBX. Combined use of rhBMP2/BCB and free periosteal graft was superior in terms of increased amount and quality of the new bone formed at the early stage of the repair process (within 12 weeks) to rhBMP2/BCB used in isolation, with the defect basically healed by 12 weeks.

CONCLUSIONS

Both methods are effective in repairing segmental bony defects, with rhBMP2/BCB used in conjunction with free periosteal graft being most preferred, considering the satisfactory osteogenesis, osteoconduction and osteoinduction.

[Location of the binary toxin gene of Bacillus sphaeriucs and some biological characteristics of its asprogenous mutants]

Location of the binary toxin gene of Bs C3-41 and some biological characteristics of its asporogenous mutants which obtained by DES treatment were studied in this paper. Mutant C4, L5 with blocked at the stage II of sporulation course were not possessed of any crystalline inclusion, but the binary toxin proteins were detected in their cells by SDS-PAGE analysis. Another mutant G5 which blocked at the stage III of sporulation course formed parasporal crystal in the cells, and its toxicity to larvae of Culex quinquefasciatus was about 50 times higher than those of mutant C4 and L5. The result of curing plasmid and Southern blot analysis confirm the binary toxin gene of Bs C3-41, Bs 1691 and Bs-10 locate on the chromosome.

Determination of dissociation constants of amino acids by capillary zone electrophoresis

A method is proposed for the determination of dissociation constants of amino acids by capillary zone electrophoresis. According to the dissociation equilibrium of amino acids and the basic theory of electrophoresis, the nonlinear relationship between the pH value of the buffer and the effective electrophoretic mobilities of the analyte was obtained. The dissociation constants can be calculated from the pH values and the corresponding effective electrophoretic mobilities using the program written in C++. The dissociation constants, pKa1 and pKa2, of 11 kinds of amino acids were determined successfully by the proposed method. The determined dissociation constants were compared with values in the literature; the differences between them are in the range of -0.03 to 0.06. No significant differences were observed between the determined dissociation constants and the corresponding literature values.

Enantiometric separation of amino acids by copper (II)-L-arginine ligand exchange capillary zone electrophoresis

A novel method for the separation of amino acid enantiomers by ligand exchange capillary zone electrophoresis (CZE) using a chiral Cu(II)-L-arginine ligand was developed in this paper. The effects of the buffer concentration, pH, the molar ratio of L-arginine to Cu(II), and the total concentrations of Cu(II) and L-arginine on the migration times and resolutions of chiral amino acids were investigated. The optimum experimental conditions were 40 mmol/L of NH4OAc, pH 7.0, the 2:1 concentration ratio of L-arginine to Cu(II), 1 mmol/L CuSO4 x 5H2O and 2 mmol/L L-arginine. Using the proposed method, six different dansyl-amino acids were separated successfully with the resolution ranging from 1.1 to 2.3 in less than 15 min.

The utility of Medicare claims data for measuring cancer stage

BACKGROUND

The validity of using claims data for measuring tumor stage, one of the most important determinants of choice of therapy and long-term survival, is unknown.

OBJECTIVES

To determine the relative accuracy of both inpatient and hospital Outpatient Medicare claims for measuring the stage of disease of six commonly diagnosed cancers.

RESEARCH DESIGN

Analysis of a database linking Surveillance, Epidemiology, and End Results (SEER) registry data and Medicare claims in patients aged 65 years with cancer.

SUBJECTS

Three hundred twenty thousand, six hundred and thirty seven cases of invasive breast, colorectal, endometrial, lung, pancreatic, and prostate cancers diagnosed between 1984 and 1993.

MEASURES

Using SEER files as the "gold standard," concordance with Medicare claims, as well as sensitivity and positive predictive value of coding for each stage was measured.

RESULTS

Although Medicare data correctly categorized local, regional, and distant stage tumors in 97%, 33%, and 65%, respectively, the data substantially overestimated the proportion of localized tumors and underestimated the rate of regional stage disease. The highest concordance was observed for breast and colorectal cancer. However, the sensitivity and positive predictive values were never simultaneously 80% within one stage of a specific cancer. The accuracy of coding for stage in Outpatient files was inferior to inpatient data.

CONCLUSIONS

With few exceptions, Medicare claims have limited utility as a measure of cancer stage. If tumor registry data are not available, investigators should consider the trade offs in sensitivity and predictive value when considering a study that will use claims data.

[Effect of calcium and cristata L extracts on bone mineral density and urinary mineral of rats]

In order to study the effect of cristata L for preventing fluoride toxicity, forty male SD rats were randomly divided into five groups. The control group(NC) was fed with staple feed stuff and tap water, the other four groups were fed with staple feed-stuff and high fluorine water. Except the high fluorine group(F), the other groups were fed with cristata L(FC), high calcium(FCa) and cristata L with high calcium(FCCa) respectively. The results showed that the serum calcium, urinary sodium, calcium, hydroxyproline(HOP) and fluorine contents of high fluorine groups were higher than that of control group; and the urinary calcium content of high calcium group was higher than that of control group. The body weight, BMC and BMD of high fluorine groups was lower than that of control group. The weight of groups FC, FCa and FCCa were significantly higher than that of group F. The BMC and BMD of group FCCa were significantly higher than that of group F. This implies that the food high in fluorine can affect the bone mineral density and urinary minerals of rats, the food supplemented with calcium can reduce the effect of high fluorine, and the food supplemented with both calcium and cristata L is better.

[Study of the 3'noncoding region of Chinese hepatitis C virus genome]

OBJECTIVE

To analyze the 3' noncoding region (3' NCR) of HCV genome from Chinese hepatitis C patients so as to facilitate further study of mechanism of HCV gene replication.

METHODS

Two different strategies were employed to amplify the full-length of the 3' noncoding region of HCV genome from sera of HCV infected patients in Shanghai area: one was to amplify the full-length fragment directly by nested PCR and the other amplify two overlapping fragments. The PCR products were further analyzed by sequencing and nucleotide alignments. A HCV genome 3'NCR based RT-PCR was developed and its specificity and sensitivity for HCV RNA detection in sera was compared with the established 5'NCR based RT-PCR.

RESULTS

Sequence analysis showed that Chinese HCV genomic 3' NCR consists of three parts: the 5' region, poly (U-UC) tract and the 98-base region. Sequence alignments revealed that, while the 98-base regions were completely conserved in different isolates and were identical to the reported sequences, the poly (U-UC) region shared highly diversities. A high degree of concordance(95%) between the 3'NCR and 5'NCR RT-PCR for detection of HCV RNA in sera was found.

CONCLUSION

The high conservation at the 3' NCR(98 bases) of HCV genome among different isolates indicated that this region may be critical for HCV gene replication The 3'NCR based RT-PCR may be a useful addition to available systems to diagnosis HCV infection.

SSA/Ro antigen expressed on membrane of UVB-induced apoptotic keratinocytes is pathogenic but not detectable in supernatant of cell culture

OBJECTIVES

To better understand the potential effect of ultraviolet light on the photosensitivity of patients with lupus erythematosus (LE), to elucidate the mechanisms of SSA/Ro antibody formation after UV exposure, and to investigate the role of this autoantibody in the pathogenesis of skin lesions.

METHODS

Primary human keratinocytes were cultured in Medium-154. After ultraviolet-B light (UVB) irradiation, the keratinocytes were treated with affinity-purified anti-SSA/Ro sera and stained with FITC-labeled goat-anti-human IgG and propidium iodide (PI), followed by enzyme digestion with RNase, RNase-free DNase or RNase plus DNase. As target cells, the irradiated keratinocytes were incubated with affinity-purified anti-SSA/Ro sera, with or without fresh human sera as complement. The supernatants of irradiated keratinocytes were analyzed with ELISA method for SSA/Ro antigens.

RESULTS

UVB irradiation induced apoptotic blebs on the cell surface. The blebs were composed of ribonucleoproteins and contained SSA/Ro antigens. SSA/Ro antigens expressed on UVB irradiated keratinocytes bound to affinity-purified anti-SSA/Ro sera, leading to complement-dependent cytotoxicity. However, no SSA/Ro antigens were detected in the supernatants.

CONCLUSIONS

SSA/Ro, a ribonucleoprotein antigen expressed on UVB irradiated keratinocytes, may be recognized and presented to immune cells by a direct cell-cell contact other than be eliminated into the circulation.

[The alternation current conductive property of blood]

The blood electro-frequency properties of normal human body were investigated in the range of 1 Hz-10 MHz. The method of testing and the equipment were examined to meet the need for the measurement of blood property. In the experiment, it was discovered that the electric conductivity of blood increased obviously with the increase of testing frequency in the rage of 100 Hz-10 KHz, but almost no change in phase was noted. This result suggests it is necessary to modify the previous work and build up a reasonable equivalent electric model of blood.

Geographic and patient variation among Medicare beneficiaries in the use of follow-up testing after surgery for nonmetastatic colorectal carcinoma

BACKGROUND

There are a paucity of data supporting the routine use of follow-up testing to detect recurrent disease after potentially curative initial surgery in patients with nonmetastatic colorectal carcinoma.

METHODS

Using the population-based Surveillance, Epidemiology, and End Results (SEER) registry, all patients age > or =65 years with local or regional colorectal carcinoma who were diagnosed in 1991, underwent surgical resection, and survived at least 6 months after diagnosis were identified. All inpatient, hospital outpatient, and physician/supplier Medicare claims from 6 months after diagnosis through 1994 were examined for follow-up procedures of interest. Procedure use during follow-up was compared across patient groups using both bivariate and multivariate analyses.

RESULTS

A total of 5716 patients were identified, with 1.3% found to have developed subsequent primary tumors of the colon or rectum, and 74% surviving through 1994. One or more procedures of interest were performed in 88% of patients; the most commonly performed tests were liver enzymes, chest X-rays, colonoscopy, and computed tomography scans. Lower rates of testing generally were observed with older age groups, patients with fewer comorbidities, and patients who did not survive through the follow-up period. Among all procedures studied, there also was significant variation in the rates of testing across the 9 SEER areas, varying from 1.5-fold to 3.6-fold. The geographic variation persisted in multivariate models adjusting for potentially confounding factors.

CONCLUSIONS

The current study found significant variability in the use of follow-up procedures, with the most striking differences apparent across geographic regions. Further studies are needed to determine the underlying reasons for the disparities, as well as the impact of surveillance on patient outcomes.

Prediction of protein subcellular locations using Markov chain models

A novel method was introduced to predict protein subcellular locations from sequences. Using sequence data, this method achieved a prediction accuracy higher than previous methods based on the amino acid composition. For three subcellular locations in a prokaryotic organism, the overall prediction accuracy reached 89.1%. For eukaryotic proteins, prediction accuracies of 73.0% and 78.7% were attained within four and three location categories, respectively. These results demonstrate the applicability of this relative simple method and possible improvement of prediction for the protein subcellular location.

Enhanced therapeutic efficacy of tumor RNA-pulsed dendritic cells after genetic modification with lymphotactin

Pulsing dendritic cells (DCs) with tumor cell-derived mRNA is regarded as an attractive alternative in the development of DC-based tumor vaccines. Our aim is to improve the therapeutic efficacy of DC-based tumor RNA vaccines by augmenting the preferential chemotaxis of DCs to T cells. Mouse bone marrow-derived DCs were genetically modified with lymphotactin (Lptn) by adenovirus vector, which conferred on DCs preferential chemotaxis to CD4+ and CD8+ T cells (Cao et al., 1998). Lptn gene-modified DCs (Lptn-DCs) were pulsed with tumor mRNA and used for vaccination in the tumor models of 3LL lung carcinoma and B16 melanoma. In both tumor models, immunization with 4 X 10(4) tumor RNA-pulsed Lptn-DCs induced more potent CTL activity, compared with their counterparts, specifically against tumor cells and Mut1 or tyrosinase-related protein 2 (TRP-2) peptide-pulsed RMA-S cells, and rendered the immunized mice resistant to tumor challenge much more effectively. CD8+ T cells were necessary and sufficient to generate the protection of Lptn-DC-based RNA tumor vaccines, and CD4+ T cells were required for the induction of tumor rejection. In the preestablished 3LL and B16 tumor models, vaccination with DC-based or LacZ-DC-based tumor RNA vaccines (2 X 10(5) cells) could reduce pulmonary metastasis and extend survival of tumor-bearing mice, but was less effective than the Lptn-DC counterpart (with 60-80% mice surviving). When the immunizing dose was decreased to 4 X 10(4) cells, Lptn-DC-based tumor vaccines rather than their counterparts were still significantly effective. Our studies provide a potential strategy to improve the efficacy of DC-based vaccines, and a new approach to immunological intervention by chemokines.

The sensitivity of Medicare claims data for case ascertainment of six common cancers

BACKGROUND

Although Medicare claims data have been used to identify cases of cancer in older Americans, there are few data about their relative sensitivity.

OBJECTIVES

To investigate the sensitivity of diagnostic and procedural coding for case ascertainment of breast, colorectal, endometrial, lung, pancreatic, and prostate cancer.

SUBJECTS

Three hundred and eighty nine thousand and two hundred and thirty-six patients diagnosed with cancer between 1984 and 1993 resided in one of nine Surveillance Epidemiology and End Results (SEER) areas.

MEASURES

The sensitivity of inpatient and Part B diagnostic and cancer-specific procedural codes for case finding were compared with SEER.

RESULTS

The sensitivity of inpatient and inpatient plus Part B claims for the corresponding cancer diagnosis was 77.4% and 91.2%, respectively. The sensitivity of inpatient claims alone was highest for colorectal (86.1%) and endometrial (84.1%) cancer and lowest for prostate cancer (63.6%). However, when Part B claims were included, the sensitivity for diagnosis of breast cancer was greater than for other cancers (93.6%). Inpatient claim sensitivity was highest for earlier years of the study, and, because of more complete data and longer follow up, the highest sensitivity of combined inpatient and Part B claims was achieved in the late 1980s or early 1990s.

CONCLUSIONS

Medicare claims provide reasonably high sensitivity for the detection of cancer in the elderly, especially if inpatient and Part B claims are combined. Because the study did not measure other dimensions of accuracy, such as specificity and predictive value, the potential costs of including false positive cases need to be assessed.

Pericardial fluid absorption into lymphatic vessels in sheep

We estimated the volumetric lymphatic clearance rate of pericardial fluid in sheep. In the first group of studies, 125I-human serum albumin (HSA) was injected into the pericardial cavity and after 4 h, various lymph nodes and tissues were excised and counted for radioactivity. Several lymphatic drainage pathways existed defined by elevated 125I-HSA in the middle and caudal mediastinal, intercostal, and the cardiac nodes located near the root of the aorta. In a second group of experiments, the plasma recovery of intrapericardially administered tracer was compared in sheep with intact lymphatics and in animals in which thoracic duct lymph was diverted and other relevant lymphatics ligated. The 4-h plasma recoveries were reduced significantly from an average of 12.2 +/- 3. 4% injected dose in the lymph-intact group to 3.0 +/- 1.1% injected dose in the diverted/ligated group (an inhibition of approximately 75%). In order to estimate the volumetric clearance of pericardial fluid through lymphatics in conscious sheep, 125I-HSA was administered into the pericardial cavity to serve as the lymph flow marker. 131I-HSA was injected intravenously to permit calculation of plasma tracer loss and tracer recirculation into lymphatics. From mass balance equations, total pericardial clearance into lymphatics averaged 1.50 +/- 0.43 ml/h or approximately 1.13 ml/h if one was to assume that the average 25% recovered plasma tracer in lymph diverted/ligated animals was due to nonlymphatic transport. In conclusion, mediastinal lymphatic pathways remove a volume equivalent to the pericardial volume (8.1 +/- 1.1 ml) every 5.4 to 7. 2 h.

[Effects of short veno-venous hemofiltration on severe acute pancreatitis]

OBJECTIVE

To estimate the effects of therapy of short veno-venous hemofiltration (SVVH, 4hr) on severe acute pancreatitis (SAP).

METHODS

Twenty patients were divided randomly into hemofiltration group (HF, 10 pts) and non-hemofiltration group (NHF, 10 pts). The local, systemic manifestations were compared between two groups; and the concentration of serum pro-inflammatory cytokines (TNFalpha, IL-1beta, IL-6, IL-8, sIL-2R) and anti-inflammatory cytokines (IL-2, IL-10) were determined at different observation points.

RESULTS

In the HF and NHF group, the duration for disappearance of abdominal pain and tenderness, and amelioration for abdominal distension was (8.5 +/- 6.3) d vs. (90.0 +/- 49.0) d and (16.9 +/- 5.2) d vs. (63.4 +/- 36.0) d. CT scores at the 14th day and APACHE II scores at the 10th day was (5.6 +/- 1.3) vs. (7.7 +/- 0.8) and (4.5 +/- 1.5) vs. (7.4 +/- 2.1). The average hospital stay and cost of therapy were (33.0 +/- 20.7) d vs. (56.4 +/- 16.0) d and (53,200 +/- 16,000) vs. (89,100 +/- 25,000) RMB (P < 0.05). The concentration of 5 serum pro-inflammatory cytokines at each observation points after hemofiltration was decreased significantly (P < 0.05) in the HF group. But the concentration of the two serum anti-inflammatory cytokines was increased significantly (P < 0.05) as compared with that of the NHF group.

CONCLUSIONS

Through SVVH, the imbalance of pro-inflammatory and anti-inflammatory cytokines has been corrected at early stage; thus, the severity of the disease is ameliorated significantly and the efficacy of therapy is increased.

Parathyroid hormone and mechanical usage have a synergistic effect in rat tibial diaphyseal cortical bone

Previous reports showed that bone mass and architecture only partially recovered by remobilization (RM) after immobilization (IM)-induced osteopenia, and that parathyroid hormone (PTH) had an anabolic effect on the skeleton. The aim of this study was to determine whether low doses of PTH could restore IM-induced cortical bone loss and whether a combination of PTH plus loading (RM) treatment would be more effective than the PTH in unloaded (IM) limbs. One hundred and sixty 6-month-old rats were divided into aging and IM groups. The right hindlimb of the rat was immobilized by elastic bandage for 18 weeks, and then groups of rats were either kept IM or RM and treated with 30 microgram or 80 microgram of hPTH(1-38)/kg/day for 2, 10, and 20 weeks. Fluorescent-labeled, undecalcified cross-sections of right tibial shafts were studied. We found that RM for 20 weeks after 18 weeks of IM only partially recovered IM-induced muscle weight loss and PTH had no effect on muscle weight in either IM or RM limbs; that RM for 20 weeks after 18 weeks of IM partially restored some minimal cortical width by stimulating periosteal and endocortical bone formation and decreasing endocortical resorption; that PTH treatment of IM limbs completely restored IM-induced cortical bone loss and added extra bone by stimulating bone formation indices on all bone surfaces and depressing bone resorption on endocortical surface; that PTH treatment of RM limbs produced similar anabolic effects as in IM limbs with 30 microgram/kg/day dose but the 80 microgram/kg/day dose-treated limbs had a higher periosteal bone formation rate, which created a larger cross-sectional area, more cortical bone area, and a thicker cortex than the same dose treated IM limbs; and that PTH 80 microgram/kg/day treatment produced more anabolic effect than the 30 microgram/kg/day in both IM and RM limbs. We concluded that reloading the hindlimb by RM after long-term IM could not recover the cortical bone mass. PTH at employed doses was able to completely restore IM-induced cortical bone loss, and this effect was independent of mechanical stimulation. However, when PTH was combined with mechanical loading (RM), a synergistic anabolic effect on periosteal bone formation occurred which increased the cross sectional area that can increase bone strength.

The presence of the Rb c-box peptide in the cytoplasm inhibits p210bcr-abl transforming function

In order to test if the carboxyl terminal polypeptide of the Retinoblastoma (Rb) tumor suppressor protein, could be used to suppress the growth factor-independent growth phenotype of p210bcr-abl positive myeloid cells, we introduced a truncated form of the 3' end of the Rb cDNA encoding its last 173 amino acid residues (Rb C-box) which localize into the cytoplasm where the p210bcr-abl transforming protein is found, into myeloid cells (32D) which depends on the p210bcr-abl protein for IL3 growth factor-independent growth (32D-p210). The expression of the plasmid vectors carrying the Rb C-box cDNAs was shown to inhibit the abl tyrosine specific protein kinase activity of the p210(bcr-abl) oncoprotein and to suppress the IL3-independent growth phenotype of the 32D-p210 cells. The Rb C-box polypeptides did not suppress the growth of the untransfected 32D parental cell line in methylcellulose in the presence of IL3-conditioned medium. These results suggest that the cytoplasmic localization of the p210(bcr-abl) allows it to escape the effect of intranuclear proteins such as Rb which negatively regulate the p145(c-abl) kinase.

[Cloning and expression of the binary toxin genes of Bacillus sphaericus C3-41 in a crystal minus B. thuringiensis subsp. israelensis]

Bacillus sphearicus C3-41, belonging to serotype H5a5b, is ahighly toxic strain isolated from a mosquito-breeding site in China. It has been shown that it had a higher toxicity against Culex spp. than the reference strain 2362 at the laboratory and field conditions. Using synthetic oligonucleotides designed on the basis of the binary toxin gene sequence of 2362, a 1.1 kb DNA fragment was produced and the genetic library was prepared from a HindIII digest of total DNA from C3-41. One colony containing the 3.5 kb HindIII fragment was selected for further studies. Sequence analysis revealed that this 3.5 kb Hind DNA fragment was composed of 3479 nucleic acids and the sequence of the binary toxin gene of C3-41 is completely identical to that of strain 2362. The toxin genes have been transferred into a nontoxic crystal-minus strain of Bacillus thuringiensis subsp. israelensis. The recombinant strains could express the binary toxin of B. sphaericus as crystaline structures during their sporulation. The expression products of the recombinants have a highly toxicity to susceptible Culex pipiens subsp. quinquefasciatus and no toxicity to resistant larvae(Culex pipiens subsp. pipiens) from France.

Interstitial brachytherapy using iridium-192 for malignant brain tumors: clinical results

OBJECTIVE

To determine the effects and toxicity of interstitial brachytherapy using iridium-192 on brain malignant gliomas.

METHODS

Between January 1992 and January 1995, 56 patients with anaplastic astrocytoma and glioblastoma multiforme were treated with stereotactic brachytherapy using temporary high-activity iridium-192 sources.

RESULTS

The median survival for patients receiving brachytherapy was 28 months. The survival rates at 1, 2, 3 years were 92.8%, 83.9% and 71.4% respectively.

CONCLUSIONS

Brachytherapy may improve the control of local tumor and prolong the survival, when used in deep malignant brain gliomas, by temporary implanted high doses of iridium-192 sources.

[The investigation of natural antibody level to Haemophilus influenzae type b polysaccharide in China]

OBJECTIVE

Investigation of natural antibody level to Haemophilus influenzae type b polysaccharide in China.

METHODS

1,596 sera samples from cord (55 sera), infants (1,383 sera), children (66 sera), adult (52 sera) and elderly (40 sera) were collected from different provinces and the natural antibody level to PRP was measured with a standardized radio immunoassay 125I-labeled PRP.

RESULTS

Antibody level of infants under 5 year olds in different provinces was different. Levels of infants from Gansu, Guizhou, Jiangxi province were lower (< or = 0.07 microgram/ml) than from Shanhai, Guangxi and Heilognjiang. Comparison of antibody levels with different age groups showed that infants aged 6 months to 5 years having the lowest antibody level (< 0.15 microgram/ml). The level increased rapidly during 6-10 years of age (> or = 1.0 microgram/ml). The levels of adults and elderly were about 1-1.5 micrograms/ml.

CONCLUSION

General immunity against Hib disease were low in Chinese population. Children aged 6 months to 5 years old with lowest natural antibody level to PRP were the population under high risk.

[Analysis of the isomers of dihydroxybenzenes by micellar electrokinetic capillary chromatography with on-column amperometric detection at carbon-fiber microelectrode]

The effects of the concentrations of beta-cyclodextrin(CD) in electrolyte on the cyclic voltammetric properties of o-, m-, p-dihydroxybenzenes at carbon-fiber microelectrode were studied. The inclusion between o-, m-, p-dihydroxybenzenes and beta-CD was investigated based on the molecular structures and experimental results. The study showed that the order of the inclusion interaction, from strong to weak, between dihydroxybenzenes and beta-CD, was m-, o- and p-dihydroxybenzenes. The effects of the concentrations of NH4Cl, SDS and beta-CD, and the pH values of the electrophoretic buffer on the migration time of o, m, p-dihydroxybenzenes were investigated. The assay of o, m, p-dihydroxybenzenes by micellar electrokinetic capillary chromatography with on-column amperometric detection at carbon-fiber microelectrode was developed. The recovery ranged from 98% to 103%.

Ameliorating effects of water-soluble polysaccharides from woody ear (Auricularia auricula-judae Quel.) in genetically diabetic KK-Ay mice

We investigated the ameliorating effects of the three groups of water-soluble polysaccharides, a mixture of crude polysaccharides (FA), acidic polysaccharide fractions (FA-A), and neutral polysaccharide fractions (FA-N), obtained from the hot water extracts of the fruit bodies of Auricularia auricula-judae Quel. In genetically diabetic KK-Ay mice from 6 to 11 weeks of age. Male mice were divided into five dietary groups: 1) control group, given a basal diet; 2) FA group, given an FA diet (15 g FA/kg diet); 3) FA-A group, given an FA-A diet (8 g FA-A/kg diet); 4) low FA-N group, given a low FA-N diet (2 g FA-N/kg diet); and 5) high FA-N group, given a high FA-N diet (8 g FA-N/kg diet). Compared with the control diet, FA supplementation had significant effects in lowering fasting and nonfasting blood glucose, HbA1c, urinary glucose, food intake, and water intake. FA administration also improved glucose tolerance to intraperitoneal glucose loading, but it did not affect the nonfasting insulin level. FA-N supplementation had dose-dependent effects in lowering fasting and nonfasting food glucose, insulin, HbA1c, urinary glucose, food intake, and water intake. However, the glucose tolerance was not ameliorated by either the low or the high FA-N diet. FA-A administration showed no beneficial effects in KK-Ay mice.

Hypoglycemic effect of water-soluble polysaccharide from Auricularia auricula-judae Quel. on genetically diabetic KK-Ay mice

The hypoglycemic effect of water-soluble polysaccharide(FA) from fruiting bodies of Auricularia auricula-judae Quel. was investigated on genetically diabetic mice (KK-Ay) from 10 to 14 weeks of age. Male mice were divided into 3 groups, the control group and FA-fed group having free access to the control diet or FA diet (30 g of FA/kg of diet). The food-restricted group had restricted access to the control diet at the level of the diet consumed by the FA-fed group. Compared with the control group, FA supplementation had a significant effect in lowering plasma glucose, insulin, urinary glucose, and food intake. FA administration also increased the tolerance to intraperitoneal glucose loading and the hepatic glycogen content. In the food-restricted group, the reduced food intake slightly lowered the plasma and urinary glucose levels, but did not improve hyperinsulinemia and glucose tolerance. This study shows that FA had a hypoglycemic effect on KK-Ay mice, and the reduced food consumption was not a major factor which contributed to the hypoglycemic action of FA.

[Free fatty acids promoting PTP1B expression in rat skeletal muscle and hepatic cells]

OBJECTIVE

To determine whether that free fatty acids (FFAs) impair glucose metabolism is associated with altered insulin signaling system.

METHODS

After skeletal muscle and hepatic cells were incubated with palmitate (0.25 mmol/L) or oleate (0.125 mmol/L) for 6, 12 or 24 hours, the protein abundance of SH-PTP2 and PTP1B was assessed by western blot.

RESULTS

SH-PTP2 protein levels showed no significant change in both fatty acids treated muscle and hepatic cells at all time points. The PTP1B was significantly elevated in both liver and muscle cells incubated with FFAs at 6, 12 and 24 hours.

CONCLUSIONS

FFAs promote the expression of PTP1B in rat skeletal muscle and liver cells, and the elevated PTP1B may mediate the insulin resistance induced by FFAs.

Exploring structure-activity relationships around the phosphomannose isomerase inhibitor AF14049 via combinatorial synthesis

Phosphomannose Isomerase (PMI) has been shown by genetic methods to be an essential enzyme in fungal cell wall biosynthesis. The PMI inhibitor AF14049 was discovered as an unanticipated side product from high-throughput library screening against the enzyme from C, albicans. Solid-phase synthetic methods were developed and a series of libraries and discrete analogs synthesized to explore SAR around AF14049.

Use of Medicare claims data to measure county-level variations in the incidence of colorectal carcinoma

BACKGROUND

Population-based cancer registries that can be used to compare cancer incidence and mortality across regions of the U.S. are currently lacking. The authors conducted this study to validate Medicare claims as a measure of county-level colorectal carcinoma incidence among older Americans. Variations found among counties are described in this article.

METHODS

A total of 183,174 hospitalized patients age 65 years in 1991-1993 with newly diagnosed colorectal carcinoma who resided in one of 480 large counties were identified in Medicare files. The county-level truncated age, race, and gender adjusted incidence rates for the population age 65 years, the proportion of patients with a code indicating distant metastases, and the 2-year case-fatality rates were determined. Corresponding rates from the SEER database were compared.

RESULTS

The median truncated adjusted 3-year incidence rate was 870 per 100,000 (Quartile 1-Quartile 3, 779-955), with almost twofold differences among counties even after the exclusion of outliers. The median proportion of patients with codes indicating distant metastases was 23.4% (range, 10.2-46.9%; Quartile 1-Quartile 3, 20.8-25.8), and the average 2-year case-fatality rate was 39.2% (range, 26.5-51.4%; Quartile 1-Quartile 3, 37.0-41.6). Medicare files tended to underestimate the truncated incidence rate according to SEER, but among counties the two sets of rates were closely correlated (r = 0.94, P < 0.0001).

CONCLUSIONS

Medicare files are a potential alternative source of national data for the study of colorectal carcinoma incidence among the elderly at the county level. The data also suggest significant variations among counties in colorectal carcinoma incidence, stage, and mortality that could be used in public health initiatives.

Eigenmode symmetry for simple cubic lattices and the transmission spectra

The existence of uncoupled modes is identified by gaps in the transmission spectra when the density of states is nonzero. We use a group theoretic analysis of the photonic band structure for a simple cubic lattice to tag the symmetry and polarization of each band. The results are compared with transmission spectra calculated by the transfer matrix method.

[The role of basic fibroblast growth factor on expression of mineralization of periodontal ligament cell population and clones]

OBJECTIVE

To determine the effect of basic fibroblast growth factor (bFGF) on mineraliztion of PDL cell clone.

METHODS

The PDL tissue that derived from three human donors was cultured and cells were cloned. The mineralizing ability were detected with or without bFGF treatment in the presence of dexamethasone. Cloned progenitor populations were assayed for their constitutive capacity to bind CAP and express ALP.

RESULTS

The results show that bFGF increases clone mineralization (11%), but not in PDL cell population. The cell clones that mineralized only in the presence of bFGF have higher CAP binding ability and lower ALP expression compared with other mineralized clone cells.

CONCLUSION

bFGF enhances mineralizing expression of PDL clone. The clones that mineralized only with bFGF treatment are different cell types from the bFGF-undependent mineralized clones.

[Study on the analysis of zinc 5-aminosalicylate and related compounds by high performance liquid chromatography]

In this paper, the separation and determination conditions of zinc 5-aminosalicylate (ZASA) and related compounds by high performance liquid chromatography(HPLC) have been studied systematically. The baseline separation was achieved at 20 degrees C on a CLC-ODS column(150 mm x 6.0 mm i.d., 10 microns) within 10 minutes by using 1% (V/V) HAc-MeOH(4:6) as mobile phase at a flow-rate of 1 mL/min. The RSDs of rention time within day and between days were less than 2% and 5% respectively. The injection volume was 20 microL, and relationships between the peak area with 280 nm detection and the analyte concentration were linear within certain ranges. This method was used for determination of ZASA, impurities and thermal decomposition compounds. The results showed that the impurities in the crude ZASA were 5-aminosalicylic acid and salicylic acid. The thermal decomposition compounds in acid medium were 5-aminosalicylic acid, 5-aminophenol and 5-benzeneazosalicylic acid.

The indeterminate gene encodes a zinc finger protein and regulates a leaf-generated signal required for the transition to flowering in maize

Flowering in plants is a consequence of the transition of the shoot apex from vegetative to reproductive growth in response to environmental and internal signals. The indeterminate1 gene (id1) controls the transition to flowering in maize. We show by cloning the id1 gene that it encodes a protein with zinc finger motifs, suggesting that the id1 gene product functions as a transcriptional regulator of the floral transition. id1 mRNA expression studies and analyses of transposon-induced chimeric plants indicate that id1 acts non-cell-autonomously to regulate the production of a transmissible signal in the leaf that elicits the transformation of the shoot apex to reproductive development. These results provide molecular and genetic data consistent with the florigen hypothesis derived from classical plant physiology studies.

Purification and physical characterization of cloned human cAMP phosphodiesterases PDE-4D and -4C

Individual isozymes of family four cyclic-nucleotide phosphodiesterases (PDE-4s) were characterized and compared in order to advance our understanding of how PDE-4s regulate cAMP levels in cells. Full-length and shorter clones containing various functional domains were constructed and overexpressed using a recombinant baculovirus-infected Sf9 insect cell system. One form each of PDE-4C and 4D was purified 125- and 534-fold, respectively, using anion-exchange and affi-gel blue chromatography. The purified material was unaltered in size on SDS-polyacrylamide gels during purification and nearly homogeneous (> 95%) as estimated by both staining and immunoblotting. Approximately 1 mg of PDE-4D (74.7 kDa) and 3.7 mg of PDE-4C (61.4 kDa) could be isolated from a 6-L culture of cells. The physical characteristics of Stokes' radius and sedimentation coefficient for PDE-4 enzymes cloned from each of the four isogenes were determined using size-exclusion chromatography and sedimentation in glycerol gradients. Calculations indicate that both long and short forms can form dimers, although evidence for monomers and higher-order subunit association was seen. Furthermore, the results clearly show that all long and short forms of PDE-4 are highly asymmetric molecules. This work has shown that large amounts of PDE-4 proteins can be purified and characterized physically and enzymatically to yield information that will enable a greater understanding of how PDE-4 enzymes function in cells.

Atrial fibrillation as a risk factor for stroke: a retrospective cohort study of hospitalized Medicare beneficiaries

OBJECTIVES

This study examined the relationship between atrial fibrillation and (1) stroke and (2) all-cause mortality.

METHODS

All eligible Medicare patients older than 65 years of age hospitalized in 1985 were followed up for 4 years. Kaplan-Meier and Cox proportional hazards models were used for assessment of risk of stroke and mortality.

RESULTS

A total of 4,282,607 eligible Medicare patients were hospitalized in 1985. The mean age was 76.1 (+/- 7.7) years; 58.7% were female; 7.2% were Black; and 8.4% had a diagnosis of atrial fibrillation. During the follow-up period, 66,063 patients (32.6/1000 person-years) developed nonembolic stroke and 7285 (3.6/1000 person-years) developed embolic stroke. After adjustment for age, race, sex, and comorbid conditions, atrial fibrillation remained a significant risk factor for both nonembolic stroke (relative risk [RR] = 1.56) and embolic stroke (RR = 5.80) and for mortality (RR = 1.31). Approximately 4.5% of nonembolic and 28.7% of embolic strokes among hospitalized Medicare patients aged 65 years and older were attributable to atrial fibrillation.

CONCLUSIONS

This study demonstrates that atrial fibrillation is associated with an appreciable increase in the risk of stroke (both embolic and nonembolic) and in the risk of mortality from all causes.

Role of protein kinase C in the regulation of pumping activity in bovine mesenteric lymphatic vessels

We investigated the role of protein kinase C (PKC) in regulating the lymphatic myogenic response. Bovine mesenteric lymphatics were suspended in an organ bath with inflow and outflow ends cannulated. Input was provided from a reservoir filled with Krebs solution. The PKC activator phorbol 12-myristate 13-acetate (PMA) inhibited pumping significantly whether tested at a fixed pressure or as pressures were raised in 2 cm H2O increments (50% inhibition achieved at 4.6 x 10(-8)M. The inactive phorbol ester (4-alpha-PMA) had no effect. The specific PKC inhibitors calphostin (10(-9) to 10(-7)M) or chelerythrine (10(-8) to 10(-6)M) had no significant effect on pumping. However, chelerythrine (10(-6)M) was capable of reversing the inhibitory effects of PMA (5 x 10(-8)M). PKC activation is believed to inhibit nitric oxide (NO) production in some blood vessels, and previous work from our laboratory has demonstrated that NO is important in facilitating pumping activity in bovine lymphatics. We observed that sodium nitroprusside (sNP, 10(-7)M) or L-arginine (10(-4)M), reversed the depressor effects of PMA. These results suggest that PKC may not be involved in regulating the vessel's contractile response to pressure-induced stretch. However, the data with PMA suggest that these ducts contain PKC. PKC activation depresses lymphatic pumping and this effect may be mediated in part, by inhibition of NO.

Amoxicillin middle ear fluid penetration and pharmacokinetics in children with acute otitis media

BACKGROUND

Acute otitis media (AOM) is a common childhood infectious disease. The efficacy of antibiotic dosing regimens is usually assessed by antibiotic plasma pharmacokinetics or middle ear fluid (MEF) concentration at one or two time points. Viral coinfection in AOM reduced antibacterial efficacy of antibiotics.

OBJECTIVE

To determine amoxicillin MEF penetration and pharmacokinetics in bacterial and combined bacterial and viral AOM.

METHODS

Thirty-four children with AOM were enrolled, and MEF was collected by tympanocentesis for bacterial culture and viral studies. Nasal wash and venous blood were also obtained for viral culture and serologic studies, respectively. Subjects were treated with amoxicillin 40 mg/kg/day orally, divided in equal doses every 8 h. During the second visit (48 to 72 h later) the subjects, with the regular morning amoxicillin dose withheld, were given an oral amoxicillin dose of 25 mg/kg. Thereafter two blood samples and one MEF sample by tympanocentesis were collected from each child at selected times between 0.5 and 4.0 h after dosing for bacterial and viral studies and amoxicillin concentration determination by high performance liquid chromatography.

RESULTS

Eleven (37%) children had only bacterial infection, 6 (20%) had viral infection only, 6 (20%) had both bacterial and viral infections and in 7 (23%) neither bacterial nor viral pathogens were recovered. MEF bacterial culture was positive in 23 of 40 ears (57.5%) before treatment with amoxicillin (40 mg/kg/day) and was still positive in 4 of 38 ears (10.5%) after 2 to 3 days of treatment. Amoxicillin plasma concentration reached its peak at 1.0 to 1.5 h after a 25-mg/kg oral dose. The estimated MEF concentration peak occurred 3.0 h after the dose with MEF concentrations ranging from undetectable to 20.6 microg/ml and a mean of approximately 9.5 microg/ml. Geometric mean amoxicillin concentrations were lowest in virus-infected children (2.7 microg/ml), nearly the same in culture-negative samples from children without viral infection (2.9 microg/ml), higher in children with combined bacterial and viral infection (4.1 microg/ml) and highest in children with bacterial-only infection (5.7 microg/ml).

CONCLUSIONS

MEF amoxicillin penetration tended to be lower in children with viral infection. The current amoxicillin dosing recommendation of 40 mg/kg/day in three divided dose is inadequate to effectively eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection. A dosing regimen of 75 to 90 mg/kg/day is recommended for AOM.

An ecological study of the effectiveness of mammography in reducing breast cancer mortality

OBJECTIVES

The purpose of this study was to determine the relation of screening mammography to breast cancer incidence and case fatality.

METHODS

In a sample of White female Medicare beneficiaries hospitalized in 1990-1991, age-adjusted breast cancer incidence and 2-year case fatality rates were estimated and compared with the frequency of mammographic screening from a population-based survey.

RESULTS

The average rates for incidence, case fatality, and mammography within 5 years in 29 states were 414/100,000, 18.8%, and 59.2%, respectively. There was a positive state-level correlation between mammography rates and incidence and an inverse correlation between mammography and case fatality.

CONCLUSIONS

High screening mammography rates in some states are associated with reduced breast cancer case fatality rates, presumably as a result of diagnosis of earlier stage cancers.

[Gene expression of thyrotropin receptor, thyroid peroxidase and thyroglobulin in autoimmune thyroid disease]

To investigate the expression of thyrotropin (TSH) receptor gene in autoimmune thyroid disease and the relationship with expression of thyroid peroxidase (TPO) and thyroglobulin (TG) genes, we examined TSH receptor, TPO and TG gene expression levels in 10 human thyroid tissues by Northern blot analysis, including 7 Graves disease (GD), 2 Hashimoto disease (HT), and 1 normal thyroid tissue. The expression levels of TSH-R gene and TG/TPO gene were different between GD group and HT group. In GD group, TSH-R gene expression was closely correlated to the expression of TPO gene (r = 0.882; P < 0.01) and TG gene (r = 0.723; P < 0.05). The gene expression levels in GD were higher than those in HT and control. In HT group, TPO, TG gene expression levels were relatively lower while TSH-R gene expression levels were still in normal range. The difference in gene expression is possibly related to the types of autoimmune antibodies and various dripping rates.

Lack of gender and racial differences in surgery and mortality in hospitalized Medicare beneficiaries with bleeding peptic ulcer

OBJECTIVE

Determine the relation of race and gender to outcome from bleeding peptic ulcer.

DESIGN

Retrospective cohort study.

SETTING

All acute care hospitals in the United States.

PATIENTS

A 100% sample of hospitalized Medicare beneficiaries older than 64 years (n = 82,868) with a primary discharge diagnosis of peptic ulcer with hemorrhage.

MEASUREMENTS AND MAIN RESULTS

Surgical treatment was performed in 6.9% of patients, 30-day mortality was 8.5%, and average length of stay was 9.4 days. Surgery was somewhat more common in men than women (7.3% vs 6.5%, p < .001), and in whites than African Americans (6.9% vs 6.3%, p < .001), but neither race nor gender was associated with surgery in multivariable analysis adjusting for potentially confounding factors. Mortality rates were similar in African Americans and whites (8.5%), and somewhat higher in men than women (10.7% vs 9.3%, p < .001). In multivariable analysis, there was no difference in mortality across gender and racial groups. Although unadjusted and adjusted lengths of stay were longer for African Americans and shorter for men, the differences were modest (i.e., 16% increase and 6% decrease in multivariable analysis, respectively, p < .0001).

CONCLUSIONS

In this national sample, there is no significant gender or racial difference in therapy and outcome for patients with hemorrhagic peptic ulcer. The findings raise the possibility that studies that have shown race and gender differences in management of coronary artery disease and cancer may not be generalizable to other common diagnoses.