An ischemic skin lesion after chemoembolization of the right internal mammary artery in a patient with hepatocellular carcinoma

A huge nodular hepatocellular carcinoma located at the anterior superior portion of the left lobe in a patient with hepatocellular carcinoma was treated with transcatheter arterial chemoembolization through the left hepatic artery. Three months later, however, there was a re-elevation of the serum alpha-fetoprotein level and evidence of a marginal recurrence at the left side of the previously embolized tumor was noted on the postembolization computed tomographic scan. Although the hepatic artery was intact in the second hepatic arteriography, we found that the right internal mammary artery was feeding the recurred hepatocellular carcinoma. This internal mammary artery was successfully treated with Lipiodol-transcatheter arterial chemoembolization. However, an ischemic lesion occurred in the skin of the anterior chest and abdominal wall several days after internal mammary artery embolization. We report here a very rare case of ischemic skin lesion on the anterior chest and abdominal wall following transcatheter arterial chemoembolization of the right internal mammary artery. This internal mammary artery was embolized because it had developed a collateral tumor feeding vessel following the initial chemoembolization of a hepatocellular carcinoma.

Apicidin, a histone deacetylase inhibitor, inhibits proliferation of tumor cells via induction of p21WAF1/Cip1 and gelsolin

Apicidin [cyclo(N-O-methyl-L-tryptophanyl-L-isoleucinyl-D-pipecolinyl -L-2-amino-8-oxodecanoyl)] is a fungal metabolite shown to exhibit antiparasitic activity by the inhibition of histone deacetylase (HDAC). In this study, we evaluated apicidin as a potential antiproliferative agent. Apicidin showed a broad spectrum of antiproliferative activity against various cancer cell lines, although with differential sensitivity. The antiproliferative activity of apicidin on HeLa cells was accompanied by morphological changes, cell cycle arrest at G1 phase, and accumulation of hyperacetylated histone H4 in vivo as well as inhibition of partially purified HDAC in vitro. In addition, apicidin induced selective changes in the expression of p21WAF1/Cip1 and gelsolin, which control the cell cycle and cell morphology, respectively. Consistent with increased induction of p21WAF1/Cip1, phosphorylation of Rb protein was markedly decreased, indicating the inhibition of cyclin-dependent kinases, which became bound to p21WAF1/Cip1. The effects of apicidin on cell morphology, expression of gelsolin, and HDAC1 activity in vivo and in vitro appeared to be irreversible, because withdrawal of apicidin did not reverse those effects, whereas the induction of p21WAF1/Cip1 by apicidin was reversible. Taken together, the results suggest that induction of histone hyperacetylation by apicidin is responsible for the antiproliferative activity through selective induction of genes that play important roles in the cell cycle and cell morphology.

A mass spectrometry method for the determination of enantiomeric excess in mixtures of D,L-amino acids

A mass spectrometry method based on ion/molecule reactions for determining enantiomeric excess in mixtures of amino acids is illustrated. Protonated complexes of amino acids with beta-cyclodextrin are produced in the gas phase using electrospray ionization. Under a background pressure of N-propylamine, the amino acid is replaced by the alkylamine. The rates of the guest exchange reaction vary with the chirality of the amino acid. A calibration curve employing varying mixtures of D- and L-amino acids is produced and the fractions of the D isomer in the test mixtures are determined. The quality of the curve is compared to the chiral selectivity of the reaction. In general, the best calibration curves are obtained in systems with the greatest selectivity.

Radiation therapy for heterotopic ossification in a patient with traumatic brain injury

Radiation therapy has been known to have a prophylactic effect for heterotopic ossification (HO), but until now it has not been known to have a therapeutic effect for established HO. We report a case of established HO compounded with a sudden increase in activity, that was improved with radiation therapy. A patient with traumatic brain injury had HO in both hips and thighs two months after the initial trauma. The existing level of HO activity suddenly increased seven months after the initial trauma, and was accompanied by severe pain that was refractory to indomethacin. We assumed that the pain was caused by the increased activity of HO on the basis of clinical symptoms and laboratory results. Initially, the patient received radiation therapy to the left lower extremity, with a total dose of 20 Gy in ten fractions. Next, the patient received radiation therapy at the same dosage to the right lower extremity, after which the pain and level of serum alkaline phosphatase significantly decreased. The patient experienced a mild pancytopenia as a side effect of the radiation therapy, but it was not severe enough to stop the radiation therapy, given the patient's suffering from the increased HO activity.

Alcohol consumption, glutathione S-transferase M1 and T1 genetic polymorphisms and breast cancer risk

To evaluate the potential association between GSTM1 and GSTT1 genotypes and development of breast cancer, a hospital based case-control study was conducted in a South Korean study population consisting of 189 histologically confirmed incident breast cancer cases and their 189 age-matched control subjects with no present or previous history of cancer. A multiplex polymerase chain reaction method was used for the genotyping analyses and statistical evaluations were performed by unconditional logistic regression model. The GSTM1 null genotype was significantly associated with breast cancer risk in premenopausal women [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1-3.7], but not in the postmenopausal women (OR = 0.9, 95% CI = 0.5-1.9), nor in all women grouped together (OR = 1.3, 95% CI = 0.8-1.1). The GSTT1 null genotype posed a similar risk of breast cancer with an OR of 1.6 (95% CI = 1.0-2.5) for the total breast cancer group, OR of 1.7 (95% CI = 0.9-3.2) for pre-menopausal women, and OR of 1.3 (95% CI = 0.6-2.8) for post-menopausal women. The breast cancer risk associated with concurrent lack of both GSTM1 and GSTT1 genes was 2.2 (95% CI = 1.1-4.5), and the risk increased as the number of null genotype increased (P for trend = 0.03). When the data were stratified by the known risk factors of breast cancer, a significant interaction was observed between the GSTM1 genotypes and alcohol consumption (P for interaction = 0.03). An especially remarkable risk of breast cancer was observed for alcohol-consuming premenopausal women lacking both the GSTM1 and GSTT1 genes (OR = 5.3, 95% CI = 1.0-27.8) compared to those with both of the genes. Our findings thus suggest a novel gene-environment interaction which plays an important role in the individual susceptibility to breast cancer. p6

Association between hepatitis B virus infection and HLA-DR type in Korea

Although the mechanism of susceptibility to chronic persistent hepatitis B virus (HBV) infection is not well clarified, immunogenetic factors of the host may have a role. Recently, a strong association between HLA-DR13 and the self-limited course of HBV infection has been reported. To determine whether the elimination of HBV is related to a particular HLA allele, we studied the HBV markers and HLA-DR phenotypes of 1,272 Koreans who had visited Yonsei University Medical Center for renal transplantation. They included 330 renal transplant donors. Subjects were categorized into 3 different groups: the "Unexposed Group" (UE; n = 946) with negative HBV markers, the "Chronic Carrier Group" (CC; n = 83), who were hepatitis B surface antigen (HBsAg)-positive, and the "Spontaneously Cleared Group" (SC; n = 243), who were HBsAg-negative with antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). HLA-DR4 was the most common type in all groups. HLA-DR6 was significantly more frequent in 69 of 243 subjects with SC (28. 4%) than in 8 of 83 subjects with CC (9.6%) (P <.001; relative risk [RR] = 3.72). HLA-DR9 was significantly more frequent in CC than in SC (P <.001; RR = 0.33). HLA-DR13 showed a stronger association with the clearance of HBV than the other HLA-DR6 subgroup. The distribution of HLA-DR phenotypes was similar regardless of renal disease. Our data indicate that HLA-DR6, especially HLA-DR13, is one of the host factors, which influences the immune response to HBV, and may be associated with self-elimination of HBV in Koreans.

Metaplastic carcinoma of the breast: mammographic and sonographic findings

PURPOSE

We investigated the mammographic, sonographic, and pathologic findings in metaplastic carcinoma of the breast.

METHODS

The mammographic (n = 16) and sonographic (n = 11) findings in 16 patients with metaplastic carcinoma of the breast were analyzed retrospectively along with pathologic findings. Whenever possible, results of preoperative fine-needle aspiration biopsy and immunohistochemical studies were obtained.

RESULTS

All patients presented with a palpable breast mass. The mean size of the lesions at pathologic examination was 4.2 cm. On mammography, 15 patients had a mass (1 patient had 2 masses), and 1 patient had only clustered microcalcifications without an associated mass. The mean longest diameter of the 16 masses on mammography was 4.6 cm. Eleven lesions (69%) were round to ovoid in shape, 13 lesions (81%) showed ill-defined or obscured margins, and 10 lesions (63%) showed associated architectural distortion. On sonography, 6 (55%) of 11 lesions were round to ovoid, 9 lesions (82%) had well-defined margins, and 6 lesions (55%) showed complex echogenicity with solid and cystic components. At pathologic examination, 4 of these 6 lesions showed hemorrhagic or cystic necrosis. Axillary lymph nodes were positive in 6 (40%) of 15 patients in whom axillary node dissection was performed.

CONCLUSIONS

Metaplastic carcinoma of the breast manifests as a rapidly growing, mammographically ill-defined round mass with associated architectural distortion on mammograms. Complex echogenicity with solid and cystic components may be seen sonographically and is related to hemorrhagic or cystic necrosis seen pathologically.

An analysis and evaluation of student nurses' participation in ethical decision making

This study analyses the types and frequencies of ethical dilemmas and the rationale of ethical decision making in student nurses; it also evaluates their decision making. One hundred senior student nurses who were enrolled in a two-credit course in nursing ethics were asked to provide an informal description of a dilemma that they had experienced during their clinical practice. The results were as follows. The ethical dilemmas identified fell into four categories and were of 27 types. Those most frequently experienced were 'family giving up on a patient because he or she could not be cured', and 'not telling the truth to the patient'. The Korean Nurses' Code of Ethics was applied, in particular the preamble, and the third, fourth, seventh and tenth clauses. The most common rule of ethics and principle applied in these nurses' ethical decision making were veracity and nonmaleficence. With regard to the moral reasoning process, the primary concern was the welfare of the patients. These students were equipped with the ability to exercise critical and reflective thought when they experienced ethical dilemmas.

Effect of the transligamentous extension of lumbar disc herniations on their regression and the clinical outcome of sciatica

STUDY DESIGN

Magnetic resonance imaging of symptomatic herniated lumbar discs was investigated longitudinally and prospectively for the presence of tear in the posterior longitudinal ligament (PLL).

OBJECTIVES

To clarify the effect of transligamentous extension through the PLL of herniated disc on its regression and to determine the factors contributing to a successful clinical outcome.

SUMMARY OF BACKGROUND DATA

Greater regression of the herniated fragment has been noted with larger initial disc herniations. The exposure of herniated disc materials to the epidural vascular supply through the ruptured PLL has been suspected to play a part in the mechanism of disappearance of the herniated nucleus pulposus. However, it had not been shown clinically.

METHODS

Clinical outcomes and magnetic resonance images of 36 patients with symptomatic lumbar disc herniations, treated conservatively, were analyzed. Patients were divided into three groups: subligamentous, transligamentous, and sequestered herniations. The size of the herniated disc was measured by herniation ratio, which is defined as the ratio of the area of herniated disc to that of the thecal sac on the axial view. Factors associated with the natural regression of herniated disc and the successful clinical outcome were explored.

RESULTS

Of the 36 herniated discs, 25 decreased in size. Ten (56%) of 18 subligamentous herniations, 11 (79%) of 14 transligamentous herniations, and all 4 (100%) sequestered herniations were reduced in size. The average decreases in herniation ratio of the subligamentous, transligamentous, and sequestered disc groups were 17%, 48%, and 82% respectively. The decrease in herniation ratio was related to the presence of transligamentous extension but was not related to the initial size of herniation. Successful outcome correlated with a decrease in herniation of more than 20%.

CONCLUSION

Transligamentous extension of herniated disc materials through the ruptured PLL is more important to its reduction in size than is the initial size of the herniated disc. Decrease in herniation ratio of more than 20% seems to correspond to successful clinical outcome.

Environment of the Gamma-Ray Burst GRB 971214: A Giant H ii Region Surrounded by a Galactic Supershell

Among a number of gamma-ray bursts whose host galaxies are known, GRB 971214 stands out for its high redshift (z>/=3) and the Lyalpha emission line having a P Cygni-type profile, which is interpreted to be a direct consequence of the expanding supershell. From a profile-fitting analysis, we estimate the expansion velocity of the supershell (vexp=1500 km s-1) and the neutral column density (NHi=1020 cm -2). The redshift z=3.418 of the host galaxy proposed by Kulkarni et al. in 1998 has been revised to be z=3.425 from our profile analysis. The observed Lyalpha profile is fitted well by a Gaussian curve, which yields the Lyalpha luminosity LLyalpha=&parl0;1.8+/-0.8&parr0;x1042 ergs s-1. Assuming that the photon source is a giant H ii region, we deduce the electron number density in the H ii region ne=&parl0;40+/-10&parr0;&parl0;L/LLyalpha&parr0;0.5&parl0;R/100 pc&parr0;-1.5 cm-3, which corresponds to the illumination by about 104 O5 stars. We estimate the star formation rate to be RSF=7+/-3 M middle dot in circle yr-1 with the internal and the Galactic extinction corrected. The theory on the evolution of supernova remnants is used to propose that the supershell is at the adiabatic phase, with its radius R=18E1&solm0;253 pc, its age t=4.7x103E1&solm0;253 yr, and the density of the ambient medium n1=5.4E-1&solm0;253 cm-3, where E53=E&solm0;1053 ergs; we estimate the kinetic energy of the supershell to be Ek=7.3x1052E53 ergs. These values are consistent with the hypothesis that the supershell is the remnant of a gamma-ray burst. We note similarities between supershells found in nearby galaxies and remote primeval galaxies and propose that the gamma-ray burst may have occurred in a giant H ii region whose environment is similar to that in star-forming galaxies.

Clustering of breast microcalcifications: revisited

AIM

To verify the diagnostic value of the traditional definition of 'clustering' of microcalcifications (more than five in the area of 1 cm(2)or 1 cm(3)) on mammography in the differential diagnosis of benign and malignant breast disease.

METHODS AND MATERIALS

Three radiologists without knowledge of the final pathology retrospectively counted the number of microcalcifications per 0.25 cm(2) (0.5 x 0.5 cm) unit area on mammography in 57 pathologically proven non-palpable lesions including 26 cancers and 31 benign diseases. Pleomorphism of the microcalcifications, associated architectural distortion or mass or increased density and distribution of microcalcifications were also evaluated.

RESULTS

The mean numbers of microcalcifications per 0.25 cm(2) were 16.4 in malignant and 16.7 in benign diseases (no statistically significant difference between the two groups). Pleomorphism of the microcalcifications, associated architectural distortion or mass or increased density were, however, important determining parameters. Clustering was more frequently observed in benign diseases.

CONCLUSION

In this study, the mean number of microcalcifications per unit area is much larger than the traditional definition of 'clustering' and clustering itself is not effective in the differential diagnosis of benign and malignant breast lesions. Imaging features other than numbers of calcification per unit area are more important in assessing the significance of mammographic clustered microcalcifications.

Regulation of G2/M progression by the STE mitogen-activated protein kinase pathway in budding yeast filamentous growth

Inoculation of diploid budding yeast onto nitrogen-poor agar media stimulates a MAPK pathway to promote filamentous growth. Characteristics of filamentous cells include a specific pattern of gene expression, elongated cell shape, polar budding pattern, persistent attachment to the mother cell, and a distinct cell cycle characterized by cell size control at G2/M. Although a requirement for MAPK signaling in filamentous gene expression is well established, the role of this pathway in the regulation of morphogenesis and the cell cycle remains obscure. We find that ectopic activation of the MAPK signal pathway induces a cell cycle shift to G2/M coordinately with other changes characteristic of filamentous growth. These effects are abrogated by overexpression of the yeast mitotic cyclins Clb1 and Clb2. In turn, yeast deficient for Clb2 or carrying cdc28-1N, an allele of CDK defective for mitotic functions, display enhanced filamentous differentiation and supersensitivity to the MAPK signal. Importantly, activation of Swe1-mediated inhibitory phosphorylation of Thr-18 and/or Tyr-19 of Cdc28 is not required for the MAPK pathway to affect the G2/M delay. Mutants expressing a nonphosphorylatable mutant Cdc28 or deficient for Swe1 exhibit low-nitrogen-dependent filamentous growth and are further induced by an ectopic MAPK signal. We infer that the MAPK pathway promotes filamentous growth by a novel mechanism that inhibits mitotic cyclin/CDK complexes and thereby modulates cell shape, budding pattern, and cell-cell connections.

Epigastric appendiceal abscess with spontaneous drainage into the stomach

The appendiceal abscess is a common complication of acute appendicitis and usually is located in the right lower quadrant of the abdomen. An epigastric appendiceal abscess has never been reported at an unusual location. We experienced an unusual case of a 49-year-old man with an epigastric appendiceal abscess. Initially, this abscess was suspected to be a pancreatic abscess. Abdominal CT scan and barium enema demonstrated a hyperrotated cecum with an appendiceal abscess in the left upper quadrant of the abdomen. An gastroscopy revealed a small fistula-like lesion with purulent coating at the bulging posterior gastric wall. The abscess resolved spontaneously. We believe that the abscess drained into the stomach through a small fistula between the stomach and abscess cavity. There was no recurrence for over 6 months.

Effects of IL-1 beta, TNF-alpha, and TGF-beta on ciliary beat frequency of human nasal ciliated epithelial cells in vitro

Previous reports suggested that several cytokines may influence the ciliary beat of the airway ciliated epithelial cells. The aim of this study is to determine the effects of cytokines including IL-1 beta, TNF-alpha, and TGF-beta on ciliary beat frequency (CBF) of human nasal ciliated epithelial cells. CBF of cultured human nasal ciliated epithelial cells was measured 24 hours after incubating with concentrations of 0.01 ng/mL, 0.1 ng/mL, 1 ng/mL, 10 ng/mL, and 100 ng/mL of each recombinant human (rh) cytokine including rhIL-1 beta, rhTNF-alpha, and rhTGF-beta. CBF was measured with time at concentrations of 1 ng/mL of rhIL-1 beta, 10 ng/mL of TNF-alpha, and 1 ng/mL of TGF-beta solutions. CBF of the human nasal ciliated epithelial cells increased after addition of rhIL-1 beta and rhTNF-alpha. Maximum CBF was observed at 1 ng/mL of rhIL-1 beta and at 10 ng/mL of rhTNF-alpha. CBF increased progressively to 4 hours after addition of rhIL-1 beta and rhTNF-alpha. Increased CBF sustained for 24 hours and decreased by 2 days. However, no variation of CBF was observed after addition of rhTGF-beta, regardless of concentrations and time. The results of this study suggest that during acute inflammation, IL-1 beta and TNF-alpha may have a potential role in defense mechanism of human nasal epithelium by regulating CBF of the nasal ciliated epithelial cells.

NO/cGMP pathway is involved in exocrine secretion from rat pancreatic acinar cells

The enzyme responsible for the synthesis of nitric oxide (NO) from L-arginine in mammalian tissues is known as nitric oxide synthase (NOS) (EC.1.14.13.39). In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat pancreatic acinar cells. Treatment of rat pancreatic acinar cells with cholecystokinin-octapeptide (CCK-OP) resulted in an increase in the arginine conversion to citrulline, the amount of NOx, the release of amylase, and the level of cGMP. Especially, CCK-OP-stimulated increase of arginine to citrulline transformation, the amount of NOx and cGMP level were completely counteracted by the inhibitor of NOS, NG-monomethyl-L-arginine (MMA), by contrast, that of amylase release was partially reduced. Furthermore, MMA-induced decrease of NOS activity and amylase release showed dose-dependent pattern. The data on the time course of CCK-OP-induced citrulline formation and cGMP rise indicate that NOS and guanylate cyclase were activated by treatment of CCK-OP. However, the mechanism of agonist-stimulated guanylate cyclase activation in acinar cells remains unknown. Therefore, activation of NOS is one of the early events in receptor-mediated cascade of reactions in pancreatic acinar cells and NO, not completely, but partially mediate pancreatic enzyme exocrine secretion.

Correlation between carotenoid concentrations in serum and normal breast adipose tissue of women with benign breast tumor or breast cancer

To evaluate the relationship between carotenoid concentrations in serum and breast tissue, we measured serum carotenoid concentrations and endogenous carotenoid levels in breast adipose tissue of women with benign breast tumor (n = 46) or breast cancer (n = 44). Before extraction, serum was digested with lipase and cholesterol esterase, and breast adipose tissue was saponified. Serum and tissue carotenoids were extracted with ether/hexane and measured by using HPLC with a C30 column. Serum retinoic acid was extracted with chloroform/methanol and measured using HPLC with a C18 column. There were no significant differences in serum carotenoids [lutein, zeaxanthin, cryptoxanthin (both alpha- and beta-), alpha-carotene, all-trans beta-carotene, 13-cis beta-carotene and lycopene], retinoids (retinol, all-trans and 13-cis retinoic acids), and alpha- and gamma- tocopherol concentrations between benign breast tumor patients and breast cancer patients. A substantial amount of 9-cis beta-carotene was present in adipose tissue and was the only carotenoid that had a significantly lower level in benign breast tumor patients than in breast cancer patients. Correlations between carotenoid concentrations in serum and in breast adipose tissue were determined by combining the data of the two groups. Concentrations of the major serum carotenoids except cryptoxanthin showed significant correlations with breast adipose tissue carotenoid levels. When the concentrations of serum carotenoids were adjusted for serum triglycerides or LDL, correlations between serum carotenoid concentrations and breast adipose tissue carotenoid levels markedly increased, including that of cryptoxanthin (P <0. 001). The strong correlation between serum carotenoid concentrations and endogenous breast adipose tissue carotenoid levels indicate that dietary intake influences adipose tissue carotenoid levels as well as serum concentrations, and that adipose tissue is a dynamic reservoir of fat-soluble nutrients.

Guillain-Barré syndrome: MR imaging findings of the spine in eight patients

PURPOSE

To evaluate magnetic resonance (MR) imaging findings of the spine in patients with Guillain-Barré syndrome.

MATERIALS AND METHODS

MR imaging findings in eight patients (three male, five female; age range, 2-47 years) with Guillain-Barré syndrome were retrospectively reviewed. Guillain-Barré syndrome was diagnosed mainly on the basis of symptoms and also on the basis of supportive ancillary data, such as the results cerebrospinal fluid analysis and electrophysiologic evaluation. In addition, follow-up MR imaging was performed in three patients, who had slight clinical improvement.

RESULTS

All patients had thickening of the intrathecal spinal nerve roots and cauda equina, with varying degrees of enhancement on gadolinium-enhanced axial T1-weighted images. Two enhancement patterns were noted. One was enhancement of both the anterior and posterior spinal nerve roots (n = 2); the other was enhancement of the anterior spinal nerve roots only (n = 6). Follow-up MR imaging in the three patients with slight improvement of symptoms revealed that the thickening and the degree of enhancement of the spinal nerve roots were diminished.

CONCLUSION

Although the enhancement of the intrathecal spinal nerve roots is not specific to Guillain-Barré syndrome and can be seen in neoplasia and other inflammatory processes, the enhancement of only the anterior spinal nerve roots is strongly suggestive of Guillain-Barré syndrome.

Reduced activity of topoisomerase II in an Adriamycin-resistant human stomach-adenocarcinoma cell line

A human stomach-adenocarcinoma cell line (MKN-45) was selected for resistance to Adriamycin by stepwise exposure to increasing concentrations of this agent. The resulting cell line (MKN/ADR) exhibited a high level of cross-resistance to topoisomerase II (topo II)-targeted drugs such as Adriamycin, mitoxantrone, and etoposide but showed no cross-resistance to other chemotherapeutic agents such as cisplatin, carboplatin, 5-fluorouracil, or mitomycin-C. P-glycoprotein encoded by the mdr-1 gene was not overexpressed in the MKN/ADR cell line. The doubling time of the MKN/ADR cell line (2.1 days) increased only slightly as compared with that of the MKN cell line (1.7 days). The patterns of cross-resistance to various chemotherapeutic agents led us to examine the cellular contents of topo II in both the drug-sensitive and the drug-resistant cells. Extractable topo II enzyme activity was 3-fold lower in MKN/ADR cells as compared with the parental MKN cells. Levels of topoisomerase I (topo I) catalytic activity were similar in both wild-type MKN and drug-resistant MKN/ADR cells. Southern-blot analysis of genomic DNA probed with topo IIalpha or IIbeta showed no sign of either gene rearrangement or hypermethylation. Northern-blot analysis revealed that both topo IIalpha and topo IIbeta mRNA transcripts were essentially identical in the MKN and MKN/ADR cells. In contrast, Western-blot analysis revealed an approximately 20-fold lower level of topo IIalpha in drug-resistant cells as compared with drug-sensitive cells, whereas topo IIbeta levels were similar in both lines. Moreover, the amount of in vivo topo IIalpha-DNA covalent complexes formed in the presence of etoposide was also approximately 20-fold lower in drug-resistant cells. No mutation was detected in the promoter region of the topo IIalpha gene in resistant cells as compared with sensitive cells. Thus, low levels of topo IIalpha polypeptide cannot be ascribed to changes in the mRNA levels. Collectively, the data suggest that a quantitative reduction in topo IIalpha may contribute to the resistance of MKN cells to Adriamycin and other topo II-targeted drugs.

Oxidations of vincristine catalyzed by peroxidase and ceruloplasmin

The dimeric Catharanthus alkaloid vincristine (1) is oxidized to the same ring fission product in incubations with either horseradish peroxidase or the human serum copper oxidase ceruloplasmin. Horseradish peroxidase-catalyzed oxidation of vincristine requires hydrogen peroxide, whereas ceruloplasmin-catalyzed oxidation of vincristine requires chlorpromazine as a "shuttle oxidant". Preparative-scale incubations allowed for the production, isolation, structural characterization, and biological evaluation of the metabolite. The metabolite was identified as the heterocyclic ring cleavage product N-formylcatharinine (5). N-Formylcatharinine was 118 times less active than vincristine in an in vitro test against a human T-cell leukemic cell line. Therefore, these enzyme-catalyzed reactions lead to bioinactivation of vincristine.

Differential expression of annexin I in human mammary ductal epithelial cells in normal and benign and malignant breast tissues

Annexins are a family of structurally related, water-soluble proteins that have calcium- and phospholipid-binding domains. Annexin I is thought to be involved in cell proliferation and differentiation and has recently been shown to be expressed on the surfaces of lymphoma cells where it acts as an endothelial cell adhesion molecule. To evaluate the expression of annexin I in relation to human breast cancer development and progression we used breast biopsy tissues. Immunohistochemical analysis of annexin I in paraffin-embedded ductal epithelial cells of various human breast tissues indicated that this annexin was not demonstrable in the ductal luminal cells of normal breast tissues (n = 11) and benign tumors (n = 10) (except for one ductal adenoma) but was generally expressed in various types of breast cancers, including noninvasive ductal carcinoma in situ (DCIS), invasive and metastatic breast tumors (n = 33). The results suggest that annexin I expression might correlate with malignant breast cancer progression but it is most likely involved at an early stage of human breast cancer development.

A stable mixed disulfide between thioredoxin reductase and its substrate, thioredoxin: preparation and characterization

The flavoenzyme thioredoxin reductase (TrR) catalyzes the reduction of the small redox protein thioredoxin (Tr) by NADPH. It has been proposed that a large conformational change is required in catalysis by TrT in order to visualize a complete pathway for reduction of equivalents. The proposal is based on the comparison of the crystal structures of TrR and glutathione reductase, the latter being a well-understood member of the enzyme family [Waksman, G., et al. (1994) J. Mol. Biol. 236, 800-816]. Bound NADPH is perfectly positioned for electron transfer to the FAD in glutathione reductase, but in TrR, these two components are 17 angstroms apart. In order to provide evidence for the proposed conformational change, a complex between TrR and its substrate Tr involving a mixed disulfide between TrR and Tr was prepared. The redox active disulfide of TrR is composed of Cys135 and Cys138, and the redox active disulfide of Tr is made up of Cys32 and Cys35. The complex C135S-C32S is prepared from forms of TrR and Tr altered by site-directed mutagenesis where Cys138 and Cys35 are remaining in TrR and Tr, respectively. The purified C135S-C32S presents a band on a nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis responding to a molecular weight sum of one subunit of TrR and one of Tr. Several observations indicate that C135S-C32S can adopt only one conformation. It was reported previously that TrR C135S can form a charge transfer complex in the presence of ammonium cation in which the donor is the remaining thiolate of Cys138 [Prongay, A.J., et al., (1989) J. Biol. Chem. 264, 2656-2664], while titration of C135S-C32S with NH4Cl does not induce charge transfer, presumably because Cys138 is participating in the mixed dissulfide. Reduction of C135S-C32S with dithiothreitol (DTT) results in a decrease of epsilon454 to a value similar to that of TrR C135S, and subsequent NH4Cl titration leads to charge transfer complex formation in the nascent TrR C135S. Reductive titrations show that approximately 1 equiv of sodium dithionite or NADPH is required to fully reduce C135S-C32S, and treatment with NH4Cl and DTT demonstrates that the mixed disulfide between Cys138 of TrR C135S and Cys35 of TrC32S that locks the structure in a conformation where FAD can be reduced by NADPH, but electrons cannot flow from FADH2 to the mixed disulfide bond.

Cost-effectiveness of low-air-loss beds for treatment of pressure ulcers

BACKGROUND

Cost-effectiveness of low-air-loss beds for the healing of pressure ulcers was analyzed in the nursing home setting. A statistical model of pressure ulcer healing was used to estimate cost-effectiveness based on patient and ulcer characteristics.

METHODS

Results of a previous randomized trial (84 patients from three nursing homes in Los Angeles) were reanalyzed and combined with estimates of costs to calculate the cost-effectiveness in dollars per added day free of pressure ulcers achieved by the use of low-air-loss beds compared to conventional foam mattresses.

RESULTS

The cost-effectiveness of the low-air-loss bed was $26 per added day free of ulcers for our standard patient. Results were sensitive to low-air-loss bed lease costs and patient and wound healing characteristics. Results were less sensitive to expected mortality, daily wound care costs, and time-frame of consideration. Low-air-loss beds were more cost-effective for patients with good healing characteristics and mild ulcers.

CONCLUSIONS

Findings support the expanded use of this technology for patients with mild pressure ulcers and good healing characteristics. For these patients, the cost-effectiveness of low-air-loss beds is comparable to other accepted health treatments. For patients with severe ulcers and poor healing characteristics, low-air-loss bed cost-effectiveness compares poorly with other accepted health treatments unless the lease cost can be substantially reduced, or unless life with a pressure ulcer is valued close to death.

Metabolism of capsaicinoids: evidence for aliphatic hydroxylation and its pharmacological implications

A new metabolic oxidation pathway of capsaicin (N-[(4-hydroxy-3-methoxyphenyl)-methyl]-8-methyl-(E)-6 -nonenamide), a major pungent and pharmacologically active principle of hot peppers, was investigated. Incubation of capsaicin with phenobarbital-induced rat liver postmitochondrial supernatant enriched with NADPH-generating system produced N-(4,5-dihydroxy-3-methoxybenzyl)-(E)-6 -nonenylamide and a more polar metabolite. The latter metabolite was spectrophotometrically and chromatographically identical to authentic omega-hydroxycapsaicin. This new metabolite was also detected in the urine of rabbits given capsaicin by gastric intubation. Other analogs of capsaicin, such as dihydrocapsaicin and nonivamide, also formed similar metabolites via aliphatic hydroxylation. When tested for antinociceptive activity as well as pungency, the above polar metabolites were found to be inactive while their parent compounds exhibited strong sensory effects. Capsaicin interacted irreversibly with heptic drug metabolizing enzymes, thereby inhibiting their activity as indicated by prolongation of pentobarbital sleeping time in rats. Such inhibition of drug metabolism was not observed with omega-hydroxycapsaicin. These findings suggest that metabolism of capsaicinoids via hydroxylation of their side chains plays an important role in the detoxification of these pharmacologically active substances.

Effects of Na+, K(+)-pump inhibitors on acetylcholine-induced relaxation in the rabbit aorta

The purpose of this study was to investigate the effects of inhibitors of the Na+, K(+)-pump and membrane depolarizing agents on endothelium-dependent acetylcholine-induced relaxation in the rabbit thoracic aorta. Aortic rings were prepared from the rabbit descending thoracic aorta and the contractility of the ring was measured in various conditions such as application of ouabain, exposure to K(+)-free Krebs-Henseleit solution and high K+. Ouabain or exposure to K(+)-free Krebs-Henseleit solution inhibited acetylcholine or sodium nitroprusside-induced relaxation. KCl also inhibited the acetylcholine or sodium nitroprusside-induced relaxation. These results suggest that the Na+, K(+)-pump may play a role in endothelium-dependent acetylcholine-induced relaxation.