Metabolic inhibition in the perfused rat heart: evidence for glycolytic requirement for normal sodium homeostasis

Subcellular compartmentalization of energy stores to support different myocardial processes has been exemplified by the glycolytic control of the ATP-sensitive K+ channel. Recent data suggest that the control of intracellular sodium (Nai) may also rely on glycolytically derived ATP; however, the degree of this dependence is unclear. To examine this question, isolated, perfused rat hearts were exposed to hypoxia, to selectively inhibit oxidative metabolism, or iodoacetate (IAA, 100 mumol/l), to selectively inhibit glycolysis. Nai and myocardial high-energy phosphate levels were monitored using triple-quantum-filtered (TQF) 23Na and 31P magnetic resonance spectroscopy, respectively. The effects of ion exchange mechanisms (Na+/Ca2+, Na+/H+) on Nai were examined by pharmacological manipulation of these channels. Nai, as monitored by shift reagent-aided TQF 23Na spectral amplitudes, increased by approximately 220% relative to baseline after 45 min of perfusion with IAA, with or without rapid pacing. During hypoxia, Nai increased by approximately 200% during rapid pacing but did not increase in unpaced hearts or when the Na+/H+ exchange blocker ethylisopropylamiloride (EIPA, 10 mumol/l) was used. Neither EIPA nor a low-Ca2+ perfusate (50 mumol/l) could prevent the rise in Nai during perfusion with IAA. Myocardial function and high-energy phosphate stores were preserved during inhibition of glycolysis with IAA and continued oxidative metabolism. These results suggest that glycolysis is required for normal Na+ homeostasis in the perfused rat heart, possibly because of preferential fueling of Na-K-adenosinetriphosphatase by glycolytically derived ATP.

Overexpression of the matrix metalloproteinase matrilysin results in premature mammary gland differentiation and male infertility

To examine the role of matrilysin (MAT), an epithelial cell-specific matrix metalloproteinase, in the normal development and function of reproductive tissues, we generated transgenic animals that overexpress MAT in several reproductive organs. Three distinct forms of human MAT (wild-type, active, and inactive) were placed under the control of the murine mammary tumor virus promoter/enhancer. Although wild-type, active, and inactive forms of the human MAT protein could be produced in an in vitro culture system, mutations of the MAT cDNA significantly decreased the efficiency with which the MAT protein was produced in vivo. Therefore, animals carrying the wild-type MAT transgene that expressed high levels of human MAT in vivo were further examined. Mammary glands from female transgenic animals were morphologically normal throughout mammary development, but displayed an increased ability to produce beta-casein protein in virgin animals. In addition, beginning at approximately 8 mo of age, the testes of male transgenic animals became disorganized with apparent disintegration of interstitial tissue that normally surrounds the seminiferous tubules. The disruption of testis morphology was concurrent with the onset of infertility. These results suggest that overexpression of the matrix-degrading enzyme MAT alters the integrity of the extracellular matrix and thereby induces cellular differentiation and cellular destruction in a tissue-specific manner.

Cytokine control of interstitial collagenase and collagenase-3 gene expression in human chondrocytes

Human collagenase-3 expression, previously seen only in a breast tumor tissue, is here shown to be expressed in primary human chondrocytes derived from the joint tissue and in transformed human chondrocytes. Its mRNA is inducible by the inflammatory cytokines interleukin-1beta plus tumor necrosis factor-alpha, but not by phorbol 12-myristate 13-acetate and only slightly by the growth factors platelet-derived growth factor and epidermal growth factor. Human synovial fibroblasts, another prominent cell type in the joint tissue, do not produce collagenase-3 message. Expression of the murine collagenase, which is possibly the counterpart of human collagenase-3, is induced by interleukin-1beta plus tumor necrosis factor-alpha, and its full induction requires the presence of the transcription factor, c-FOS. This family of transcription factors also plays a role in induction of human collagenase-3, since it binds to the AP-1 site of this matrix metalloproteinase.

Human endometrial matrix metalloproteinase-2, a putative menstrual proteinase. Hormonal regulation in cultured stromal cells and messenger RNA expression during the menstrual cycle

Proteinases are likely effectors of endometrial menstrual breakdown. We have investigated proteinase production by human endometrial stromal cells subjected in vitro to progesterone (P) withdrawal, the physiologic stimulus for menstruation. Culture media of cells exposed to estradiol, P, or estradiol plus P had low levels of proteolytic activity similar to cultures maintained in the absence of steroids. P withdrawal, or addition of RU486 to P-treated cultures, stimulated proteinase secretion. The stromal cell proteinase was characterized by gelatin zymography, inhibitor profile, and organomercurial activation, as a metalloproteinase present mostly as a 66-kD proenzyme with lower levels of a 62-kD active form. The P withdrawal-induced metalloproteinase was identified as matrix metalloproteinase-2 (MMP-2) by Western blotting. The increase of MMP-2 induced by P withdrawal was associated with the metalloproteinase-dependent breakdown of stromal cultures, involving dissolution of extracellular matrix and dissociation of stromal cells. Northern analysis showed the differential expression of MMP-2 mRNA in late secretory phase endometrium. These findings are consistent with the involvement of stromal cell-derived MMP-2 in the proteolysis of extracellular matrix promoting cyclic endometrial breakdown and the onset of menstrual bleeding.

Victim as offender in youth violence

STUDY OBJECTIVE

To determine how often adolescent and young adult victims of assaultive injury are offenders in assaults and other crimes.

DESIGN

Comparison of 10- to 24-year-old males treated in the accident and emergency department for assault-related injuries to similar-aged males treated in the same department for unintentional injuries. Police records were searched on both groups for warnings or convictions.

SETTING

Accident and emergency department of the Cardiff Royal Infirmary.

RESULTS

Assault patients were significantly more likely to be formally warned or convicted, and they had a higher mean number of warnings or convictions per 100 person-years of exposure, than other injury patients. These differences were most pronounced for the younger patients and for the year following the injury.

CONCLUSION

These results suggest that many young male assault patients either have a history of criminal activity or develop criminal behavior subsequent to their assault and may benefit from appropriate intervention aimed at interrupting the cycle of crime and violence.

The economics of orphan drug policy in the US. Can the legislation be improved?

This review of the US Orphan Drug Act (ODA) 1983 outlines how the ODA is intended to stimulate orphan drug research and development of drugs for rare diseases. We also evaluate the effectiveness of the ODA in the past decade and provide recommendations for ODA improvements in the future. The economic incentives embedded in the ODA are presented in a simple economic model, in which a guarantee of market exclusivity plays a central role in encouraging firms to pursue the development of orphan products. Some evidence suggests that this provision has been a major impetus for the rise in orphan drug applications and designations in the last decade. Market exclusivity is the key incentive for orphan drug research, and should be retained. Concerns about a limited number of highly successful 'blockbuster' orphan drugs should be evaluated in terms of the useful economic incentives. In the future, exceptionally high profits could be limited by more precise evaluation of disease prevalence, elasticity of demand, and the other uses of orphan compounds. We further recommend an expansion of the ODA tax credits and research grants programme and targeting of 'priority' diseases. We conclude that the ODA has been a valuable legislative initiative, but it can be strengthened with some simple extensions of the current incentives that it contains.

A new immunohistochemical antibody for the assessment of estrogen receptor status on routine formalin-fixed tissue samples

We describe a method for the immunocytochemical assessment of estrogen receptor (ER) status on routinely processed, formalin-fixed tissue using a recently developed commercially available monoclonal antibody (Dako 1D5) with a microwave antigen retrieval technique. A series of 90 cases of human breast carcinoma was analyzed and the staining was assessed using a semiquantitative microscopic scoring method and by assessment of the percentage of nuclei showing positive staining. The results were compared with assessment using another commercially available antibody (Abbott H222) and with clinical response to tamoxifen therapy. Direct comparison of the paired sets of H scores and the percentage of positively stained nuclei using the two different techniques showed a significant correlation. By assigning an arbitrary cut-off for positivity of H score = 50, assessment of ER status using DAKO 1D5 antibody was found to correlate with response to tamoxifen therapy with a sensitivity of 90% and a specificity of 51%, similar to values in previous studies using other methods. We conclude that assessment of ER status using this new antibody and technique gives accurate results on routinely processed, formalin-fixed tissue and may be used as an alternative to other methods.

Modulation of matrilysin levels in colon carcinoma cell lines affects tumorigenicity in vivo

The expression of the metalloproteinase matrilysin in the human colon carcinoma cell lines SW480 and SW620 correlates with the ability of the SW620 cells to invade an artificial basement membrane in vitro and metastasize to the liver following injection into the cecum of nude mice in vivo. Transfection of either wild-type or activated forms of matrilysin into the SW480 cells, which do not express endogenous matrilysin, did not reproducibly increase in vitro invasion but increased the tumorigenicity of the cells when injected into the cecum of nude mice. Antisense reduction of matrilysin levels decreased the tumorigenicity of the SW620 cells and subsequent metastasis to the liver. These results suggest that matrilysin gene expression by colon adenocarcinoma cells is not sufficient for tumor invasion and metastasis but contributes to the tumorigenicity and progression of colorectal tumors.

Patterns of matrix metalloproteinase expression in cycling endometrium imply differential functions and regulation by steroid hormones

Matrix metalloproteinases are a highly regulated family of enzymes, that together can degrade most components of the extracellular matrix. These proteins are active in normal and pathological processes involving tissue remodeling; however, their sites of synthesis and specific roles are poorly understood. Using in situ hybridization, we determined cellular distributions of matrix metalloproteinases and tissue inhibitor of metalloproteinase-1, an inhibitor of matrix metalloproteinases, in endometrium during the reproductive cycle. The mRNAs for all the metalloproteinases were detected in menstrual endometrium, but with different tissue distributions. The mRNA for matrilysin was localized to epithelium, while the others were detected in stromal cells. Only the transcripts for the 72-kD gelatinase and tissue inhibitor of metalloproteinases-1 were detected throughout the cycle. Transcripts for stromelysin-2 and the 92-kD gelatinase were only detected in late secretory and menstrual endometrium, while those for matrilysin, the 72-kD gelatinase, and stromelysin-3 were also consistently detected in proliferative endometrium. These data indicate that matrix metalloproteinases are expressed in cell-type, tissue, and reproductive cycle-specific patterns, consistent with regulation by steroid hormones, and with specific roles in the complex tissue growth and remodeling processes occurring in the endometrium during the reproductive cycle.

Transforming growth factor-alpha and endocrine sensitivity in breast cancer

The expression of transforming growth factor-alpha (TGF-alpha) has been evaluated in 51 breast cancers of known responsiveness to endocrine therapy using immunohistochemistry. High levels of TGF-alpha were observed in 65% of tumors and showed no relationship with tumor estrogen receptor or epidermal growth factor receptor status or Ki67 immunostaining. TGF-alpha levels did, however, relate to the endocrine sensitivity of the disease, with unresponsive tumors frequently showing high levels of TGF-alpha immunoreactivity. This relationship was observed in estrogen receptor-positive disease and was independent of the epidermal growth factor receptor status of the tumor. No quantitative association between TGF-alpha and Ki67 immunostaining was observed in any of the subcategories of tumors. These data infer a role for TGF-alpha in the development of endocrine insensitivity in estrogen receptor-positive breast cancer by mechanisms which appear independent of tumor growth fraction, as determined by Ki67 immunostaining.

Analysis of Tat function in human immunodeficiency virus type 1-infected low-level-expression cell lines U1 and ACH-2

The U1 and ACH-2 cell lines are subclones of human monocytic and T-lymphoid cells, respectively, persistently infected with human immunodeficiency virus type 1. These cell lines harbor the viral genome but produce only very low levels of viral progeny, which can be increased by stimulation with agents such as phorbol ester and cytokines. As such, they provide an in vitro model for human immunodeficiency virus type 1 latency. In order to examine the basis for their latent state, we have analyzed the activity of endogenous Tat protein in these cells and investigated the effect on viral replication of the addition of exogenous Tat protein. We find that U1 cells seem to have levels of Tat protein that are suboptimal for long terminal repeat (LTR) transcription, because transcription from a transfected LTR-chloramphenicol acetyltransferase plasmid can be enhanced by cotransfection of a Tat expression plasmid. Furthermore, viral replication can be stimulated in this cell line by incubation with purified Tat protein. In contrast, ACH-2 cells are not limited for LTR-chloramphenicol acetyltransferase transcription by endogenous levels of Tat, and virus production is not increased by the addition of exogenous Tat protein. By semiquantitative PCR analysis of viral RNA, we have demonstrated that Tat protein caused an increase in human immunodeficiency virus RNA expression in U1 cells but had no effect in ACH-2 cells. This suggests that a different mechanism underlies the latent state in U1 and ACH-2 cells.

Inhibition of human immunodeficiency virus type 1 Tat-dependent activation of translation in Xenopus oocytes by the benzodiazepine Ro24-7429 requires trans-activation response element loop sequences

Two benzodiazepine compounds, [7-chloro-5-(2-pyrryl)-3H-1,4 benzodiazapin-2-(H)-one] (Ro5-3335) and [7-chloro-5-(1H-pyrrol-2-yl)-3H-benzo[e] [1,4] diazepin-2-yl]- methylamine (Ro24-7429), inhibit human immunodeficiency virus type 1 (HIV-1) replication via a specific effect on the function of the transactivator protein, Tat. To gain further insight into the mechanism of action of these compounds, we have tested their effects in an alternative assay for Tat activation in Xenopus oocytes. In this system, translation of trans-activation response element (TAR)-containing RNA is activated by Tat. Both compounds specifically blocked activation of translation in a dose-dependent fashion, with Ro24-7429 showing the greater potency. In the Xenopus oocyte system, as in mammalian cells, mutation of the TAR loop sequences abolishes Tat action. However, it is possible to obtain TAR-specific, Tat-dependent activation of a target RNA with a mutation in the loop provided that this target is in large excess. This result has been interpreted as indicating that a negative factor has been titrated (M. Braddock, R. Powell, A.D. Blanchard, A.J. Kingsman, and S.M. Kingsman, FASEB J. 7:214-222, 1993). Interestingly Ro24-7429 was unable to inhibit the TAR-specific but loop sequence-independent mode of translational activation. This finding suggests that a specific loop-binding cellular factor may mediate the effects of this inhibitor of Tat action. Consistent with this notion, we could not detect any effect of Ro24-7429 on the efficiency of specific Tat binding to TAR in vitro.

Epidermal growth factor receptor expression in breast cancer: association with response to endocrine therapy

106 previously untreated breast cancer patients have been immunohistochemically analysed for EGF-R, ER, Ki67, and c-erbB-2 product. All patients received assessable endocrine therapy following disease progression. Significant associations were observed between EGF-R and ER (inverse) and Ki67 (direct). No association was observed between EGF-R and the c-erbB-2 product. EGF-R expression was significantly associated with the loss of endocrine sensitivity in breast cancer. This was observed in both ER positive and negative disease. In ER positive breast cancers, EGF-R expression had no significant influence on the quality of tumour remissions. Further sub-classification of the ER/EGF-R data by Ki67 immunostaining showed that in ER+/EGF-R-disease, increasing proportions of Ki67 positive cells were associated with a decline in the numbers of women experiencing good quality tumour remissions. A similar trend was also observed in ER+/EGF-R+ tumours. The presence of c-erbB-2 protein product did not influence endocrine sensitivity in any of the ER/EGF-R sub-groups.

Oestrogen-regulated genes in breast cancer: association of pLIV1 with lymph node involvement

In order to isolate markers of oestrogen responsiveness in breast cancer, we have cloned a number of oestrogen-regulated genes. Two of these, pLIV1 and pLIV2 (pS2), have been shown to be predominantly expressed in oestrogen receptor (ER)+ tumours. In this study, we examined their expression in relation to various clinical and histopathological features of breast cancer, and showed that pLIV1, but not pS2, is significantly associated with lymph node involvement (P < 0.01), while pS2 is more frequently observed in premenopausal patients (P < 0.05). Subdivision of the pLIV1 data by ER and nodal status of the tumour identified a highly significant association between pLIV1 expression and lymph node involvement in ER-positive disease, with 15/24 (63%) ER+ pLIV1+ tumours showing nodal involvement. Conversely, 20/23 (87%) ER+ pLIV1- patients were lymph node-negative (P < 0.001). Subdivision of the pS2 data by ER status did not reach significance. The application of pLIV1 as a marker of lymph node involvement was further exemplified in small tumours (< < 2 cm), where 11/12 (92%) lymph node-positive patients expressed pLIV1, while 17/22 (77%) node-negative patients were pLIV1 negative (P < 0.001). Similarly, pLIV1 expression identified lymph node involvement in moderately differentiated tumours (P < 0.01), but was independent of vascular invasion. pLIV1 may, therefore, represent a candidate gene for metastatic spread in ER+ breast cancer.

Reduced expression of AP27 protein, the product of a growth factor-repressible gene, is associated with diminished adipocyte differentiation

We have recently characterized an adipocyte cDNA (clone 5) that is enhanced in expression by environmental and hormonal conditions favoring adipogenic differentiation. Moreover, certain agents including fibroblast growth factor and phorbol 12-myristate 13-acetate (but not epidermal growth factor) markedly inhibit clone 5 gene expression and prevent TA1 cell differentiation. These results led us to propose that a threshold level of the clone 5 gene product (AP27 protein) is required for triggering adipocyte differentiation. We have constructed vectors that direct the synthesis of clone 5 antisense RNA to reduce the levels of AP27 in adipogenic cell lines TA1 and 3T3-L1. We show here that when these cells express clone 5 antisense RNA, they fail to undergo morphological differentiation, whereas adipogenesis is unaffected in cells expressing antisense beta-actin or ferritin heavy-chain RNA. We further show that cells expressing clone 5 antisense RNA (but not the other antisense RNAs) are unable to induce the expression of characteristic "adipocyte-specific" mRNAs. The level of inhibition of differentiation by clone 5 antisense RNA correlates with decreased levels of AP27 protein. These results provide strong evidence that expression of AP27 is linked to adipogenic differentiation and that AP27 may be a component of an as-yet-uncharacterized signal-transduction pathway required for the triggering of adipocyte differentiation.

Nifedipine in the treatment of hypertension

Nifedipine, a calcium antagonist with a predominant vasodilator action, was evaluated for the treatment of hypertension. A 20 mg-tablet, with a slower absorption and a more sustained blood-level than provided by the 10 mg-capsule was administered to 20 patients. The duration of the trial was 20 weeks. All patients achieved a significant reduction in both systolic (p less than 0.05) and diastolic (p less than 0.001) blood-pressure (B.P.), but 10 patients were withdrawn before completion of the trial period. Two patients, although achieving a fall in B.P. which was significant, did not reach to target level (less than 160/90) on maximal dosage, one patient suffered a stroke due to a cerebral infarct, and seven patients were withdrawn because of side-effects due mainly to vasodilatation. The remaining 10 patients obtained a satisfactory response. In nine patients, who had achieved a satisfactory result, there was no change in plasma renin activity (P.R.A.) during chronic nifedipine administration.

Administering the contract

Administering the collective bargaining contract is a challenging and important nursing administration responsibility. This article discusses the attitudes, skills, and strategies that the nursing administrator who manages a unionized professional staff can use to minimize employee grievances and foster a professional practice climate. Directors of nursing in nonunionized settings also can use these guidelines to maintain the union-free status of their departments.

Glucagon as a hypotonic agent in cholangiography

The effects of Glucagon on 35 cholangiographic studies was examined. Relief of spasm at the choledochoduodenal sphincter resulted in consistently improved demonstration of this area. Diminished spasm-induced pain was also recorded. The use of intravenous Glucagon is recommended for cholangiographic studies where there is total biliary obstruction, or where there is unsatisfactory demonstration of the choledocho-duodenal area.