Reflections of desire: the poetics of gender in "Dream of the Red Chamber"

Abstract

Woven into the structure of the Dream of the Red Chamber is an exploration of the self-expressive values associated with the late imperial cult of qing and an explicit warning about the self-destructive potential of desire. Rather than being rooted in biological sex, Cao Xueqin's polysemous use of gender reflects the competing visions of Confucian orthodoxy and the cult of qing. This paper analyzes the structural and ideological values associated with masculine and feminine in Dream to argue that manipulation of gendered identities was an explicit aspect of the poetics of eighteenth-century xiaoshuo fiction.

Can a rheological muscle model predict force depression/enhancement?

A new phenomenological model of activated muscle is presented. The model is based on a combination of a contractile element, an elastic element that engages upon activation, a linear dashpot and a linear spring. Analytical solutions for a few selected experiments are provided. This model is able to reproduce the response of cat soleus muscle to ramp shortening and stretching and, unlike standard Hill-type models, computations are stable on the descending limb of the force-length relation and force enhancement (depression) following stretching (shortening) is predicted correctly. In its linear version, the model is consistent with a linear force-velocity law, which in this model is a consequence rather than a fundamental characteristic of the material. Results show that the mechanical response of activated muscle can be mimicked by a viscoelastic system. Conceptual differences between this model and standard Hill-type models are analyzed and the advantages of the present model are discussed.

Pathophysiology of diabetic nephropathy

Diabetic nephropathy (DN) is now the commonest cause of end-stage renal failure in the Western world. Recent studies examining the pathogenesis of diabetic complications have focused on the complex interaction between genetic and hemodynamic mechanisms in addition to metabolic factors such as advanced glycation, protein kinase C (PKC) activation, and polyol production. The importance of the various components, particularly with regard to the progression of DN, is currently being explored with the assistance of targeted drug intervention studies.

Material and functional properties of articular cartilage and patellofemoral contact mechanics in an experimental model of osteoarthritis

The purposes of this study were to determine the in situ functional and material properties of articular cartilage in an experimental model of joint injury, and to quantify the corresponding in situ joint contact mechanics. Experiments were performed in the anterior cruciate ligament (ACL) transected knee of the cat and the corresponding, intact contralateral knee, 16 weeks following intervention. Cartilage thickness, stiffness, effective Young's modulus, and permeability were measured and derived from six locations of the knee. The total contact area and peak pressures in the patellofemoral joint were obtained in situ using Fuji Pressensor film, and comparisons between experimental and contralateral joint were made for corresponding loading conditions. Total joint contact area and peak pressure were increased and decreased significantly (alpha=0.01), respectively, in the experimental compared to the contralateral joint. Articular cartilage thickness and stiffness were increased and decreased significantly (alpha=0.01), respectively, in the experimental compared to the contralateral joint in the four femoral and patellar test locations. Articular cartilage material properties (effective Young's modulus and permeability) were the same in the ACL-transected and intact joints. These results demonstrate for the first time the effect of changes in articular cartilage properties on the load transmission across a joint. They further demonstrate a substantial change in the joint contact mechanics within 16 weeks of ACL transection. The results were corroborated by theoretical analysis of the contact mechanics in the intact and ACL-transected knee using biphasic contact analysis and direct input of cartilage properties and joint surface geometry from the experimental animals. We conclude that the joint contact mechanics in the ACL-transected cat change within 16 weeks of experimental intervention.

Efficacy and safety of an over-the-counter transdermal nicotine patch as an aid for smoking cessation

OBJECTIVE

To evaluate the efficacy and safety of a transdermal nicotine patch as an aid for smoking cessation in an over-the-counter setting.

DESIGN

Multicenter, double-blind, randomized, placebo-controlled trial of 6-week duration with 18 weeks of follow-up.

SETTING

Four shopping mall precincts.

PARTICIPANTS

The randomized sample consisted of 802 adults (mean age, 39 years) and was 89% white and 54% female. A smoking history of at least 20 cigarettes per day for 1 year and a score of 5 (on a 10-point scale) on a motivational assessment questionnaire were required for enrollment. Poststudy follow-up was limited to those who had quit smoking at the end of 6 weeks.

INTERVENTION

Nicotine patches were provided at the shopping mall. Guidance consisted only of package instructions and a smoking cessation self-help booklet.

MAIN OUTCOME MEASURES

Quit rates were defined as total abstinence from smoking for 4 consecutive weeks (treatment weeks 3-6), point prevalence smoking status at week 6, or nonsmoker at week 6 and week 24 (6-month postquit date). Smoking status was assessed by diaries, and verification for the first 2 quit rates was obtained by confirmation of carbon monoxide of 8 ppm or less in expired breath. Safety was evaluated by self-reported adverse events.

RESULTS

Quit rate was 12% for the active treatment group and 5.5% for the placebo group, based on total abstinence for 4 consecutive weeks (P = .001) compared with quit rates of 19.5% and 7.5% for active treatment and placebo groups, respectively, based on point prevalence data at week 6. At 24 weeks, 8.2% of nonsmokers in the active treatment group and 4.0% in the placebo group remained nonsmokers. At least 1 adverse event was reported by 57% receiving the nicotine patch and 39% receiving placebo (P<.001).

CONCLUSIONS

When the nicotine patch was used in an over-the-counter setting, quit rates were comparable to those reported for medical settings. A 2:1 quit rate advantage was achieved at week 6 and was maintained at 24 weeks.

Effects of inserting a pressensor film into articular joints on the actual contact mechanics

Fuji film has been widely used in studies aimed at obtaining the contact mechanics of articular joints. Once sealed for practical use in biological joints, Fuji Pressensor film has a total effective thickness of 0.30 mm, which is comparable to the cartilage thickness in the joints of many small animals. The average effective elastic modulus of Fuji film is approximately 100 MPa in compression, which is larger by a factor of 100-300 compared to that of normal articular cartilage. Therefore, inserting a Pressensor film into an articular joint will change the contact mechanics of the joint. The measurement precision of the Pressensor film has been determined systematically; however, the changes in contact mechanics associated with inserting the film into joints have not been investigated. This study was aimed at quantifying the changes in the contact mechanics associated with inserting sealed Fuji Pressensor film into joints. Spherical and cylindrical articular joint contact mechanics with and without Pressensor film and for varying degrees of surface congruency were analyzed and compared by using finite element models. The Pressensor film was taken as linearly elastic and the cartilage was assumed to be biphasic, composed of a linear elastic solid phase and an inviscid fluid phase. The present analyses showed that measurements of the joint contact pressures with Fuji Pressensor film will change the maximum true contact pressures by 10-26 percent depending on the loading, geometry of the joints, and the mechanical properties of cartilage. Considering this effect plus the measurement precision of the film (approximately 10 percent), the measured joint contact pressures in a joint may contain errors as large as 14-28 percent.

Calcium antagonists and renal protection: emerging perspectives

During the past two decades, major investigative interest has focused on the determinants of chronic renal disease and interventions that retard the inexorable progression to end-stage renal disease. Recent studies have provided a theoretic framework for anticipating that angiotensin-converting enzyme (ACE) inhibitors, and possibly calcium antagonists, may preferentially retard the progression of renal disease. Whereas the majority of available clinical trials have assessed the effects of ACE inhibitors in patients with insulin-dependent diabetes mellitus, relatively few long-term studies have evaluated the renoprotective effects of ACE inhibitors and calcium antagonists in patients with nondiabetic renal disease. Recent observations suggest that the two classes of drugs act in a complementary manner to countervail pathogenetic mechanisms at the level of the mesangium. Such observations recently prompted randomized prospective studies that compare the renoprotective effects of calcium antagonist versus ACE inhibitor monotherapy in both diabetic patients and patients with nondiabetic renal disease.

Mutation analysis of the MEN1 gene in multiple endocrine neoplasia type 1, familial acromegaly and familial isolated hyperparathyroidism

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant disease characterized by neoplasia of the parathyroid glands, the endocrine pancreas, and the anterior pituitary gland. In addition, families with isolated endocrine neoplasia, notably familial isolated hyperparathyroidism (FIHP) and familial acromegaly, have also been reported. However, whether these families constitute MEN 1 variants or separate entities remains speculative as the genetic bases for these diseases are unclear. The gene for MEN 1 has recently been cloned and characterized. Using single strand conformation analysis (SSCA) and sequencing, we performed mutation analysis in: a) a total of 55 MEN 1 families from 7 countries, b) 13 isolated MEN 1 cases without family history of the disease, c) 8 acromegaly families, and d) 4 FIHP families. Mutations were identified in 27 MEN 1 families and 9 isolated cases. The 22 different mutations spread across most of the 9 translated exons and included frameshift (11), nonsense (6), splice (2), missense mutations (2), and in-frame deletions (1). Among the 19 Finnish MEN 1 probands, a 1466del12 mutation was identified in 6 families with identical 11q13 haplotypes and in 2 isolated cases indicating a common founder. One frameshift mutation caused by 359del4 (GTCT) was found in 1 isolated case and 4 kindreds of different origin and haplotypes; this mutation therefore represents a common "warm" spot in the MEN1 gene. By analyzing the DNA of the parents of an isolated case one mutation was confirmed to be de novo. No mutation was found in any of the acromegaly and small FIHP families, suggesting that genetic defects other than the MEN1 gene might be involved and that additional such families need to be analyzed.

The temporal profile and morphologic features of neuronal death in human stroke resemble those observed in experimental forebrain ischemia: the potential role of apoptosis

Although neuronal death has been studied in experimental models of ischemia, the precise mechanisms regulating cell death remain unclear. Furthermore, the timing and pattern of neuronal death in human stroke has not been extensively studied. To further our understanding of ischemia-induced neuronal death, we examined the temporal profile of histochemical and morphologic characteristics of hippocampal neuronal death following experimental forebrain ischemia and compared these findings to human brain specimens obtained from subjects suffering cerebral infarction. Transient forebrain ischemia (TFI) was induced in normothermic adult rats by bilateral carotid artery occlusion combined with hypotension. Animals were sacrificed at 6, 12, 18, 24, 48, and 72 h and 7, 14, and 28 days following ischemia (n = 4 at each time point). Experimental tissue was analyzed using light and electron microscopy as well as TUNEL histochemistry. A total of 27 human brain specimens with neuropathological confirmation of ischemic damage and appropriate controls were also examined using light microscopy and TUNEL histochemistry. Dense TUNEL staining in hippocampal CA-1 neurons was present at 48 and 72 h following experimental ischemia. Prior to these times, little or no nuclear staining was noted and after 72 h nuclear staining diminished rapidly. Ultrastructural findings at these time points demonstrated many features similar to those seen in cells undergoing apoptosis, such as cell shrinkage with increased electron density, chromatin condensation with formation of heterochromatin, intact plasma membranes, and intact intracellular organelles. In a similar fashion, human stroke specimens during the subacute period showed dense nuclear TUNEL staining in penumbral neurons, whereas in the acute or chronic stages little or no staining was noted. Our results demonstrate that the timing of morphologic changes and TUNEL histochemistry following human stroke resembles that observed in experimental TFI. Furthermore, neuronal death in both experimental ischemia and human stroke share several features characteristic of apoptotic cell death.

The Xcad-2 gene can provide a ventral signal independent of BMP-4

Patterning of the marginal zone in the Xenopus embryo has been attributed to interactions between dorsal genes expressed in the organizer and ventral-specific genes. In this antagonistic interplay of activities, BMP-4, a gene that is not expressed in the organizer, provides a strong ventralizing signal. The Xenopus caudal type homeobox gene, Xcad-2, which is expressed around the blastopore with a gap over the dorsal lip, was analyzed as part of the ventral signal. Xcad-2 was shown to efficiently repress during early gastrula stages the dorsal genes gsc, Xnot-2, Otx-2, XFKH1 and Xlim-1, while it positively regulates the ventral genes, Xvent-1 and Xvent-2, with Xpo exhibiting a strong positive response to Xcad-2 overexpression. Xcad-2 was also capable of inducing BMP-4 expression in the organizer region. Support for a ventralizing role for Xcad-2 was obtained from co-injection experiments with the dominant negative BMP receptor which was used to block BMP-4 signaling. Under lack-of-BMP-signaling conditions Xcad-2 could still regulate dorsal and ventral gene expression and restore normal development, suggesting that it can act downstream of BMP-4 signaling or independently of it. Xcad-2 could also inhibit secondary axis formation and dorsalization induced by the dominant negative BMP receptor. Xcad-2 was also shown to efficiently reverse the dorsalizing effects of LiCl. These results place Xcad-2 as part of the ventralizing gene program which acts during early gastrula stages and can execute its ventralizing function in the absence of BMP signaling.

Potential of dopamine A-1 agonists in the management of acute renal failure

Many therapeutic approaches have been undertaken both to prevent acute ischemic or nephrotoxic renal injury and, once acute renal failure (ARF) has developed, to improve renal function and reduce mortality. To date, most therapeutic studies have investigated the effects of diuretics (eg, mannitol, furosemide), vasoactive agents (calcium channel blockers, atrial natriuretic peptide), or dopamine (a nonselective dopaminergic agent [DAA]) in one or more phases of ARF. Unfortunately, studies of the use of DAA in ARF are complicated by the existence of at least two different DAA receptors (DA-1 and DA-2), and by the stimulation of alpha- and/or beta-adrenergic receptors by high doses of DAA. The undesirable side effects of high doses of dopamine and the inconclusive results using low doses (ie, "renal doses") of dopamine (a nonselective DAA) have prompted consideration of the use of more selective dopaminergic agonists for the prophylaxis and treatment of ARF. Selective DA-1 agonists exhibit many desirable renal effects that theoretically support their use for the prophylaxis and/or treatment of ARF, including decreases in renal vascular resistance accompanied by increases in renal blood flow and glomerular filtration rate, and increases in sodium excretion and urine volume. Even at high doses, some selective DA-1 agonists, such as fenoldopam, do not stimulate DA-2 receptors, or adrenergic alpha- or beta-receptors, and thus are free of unwanted side effects (eg, arrhythmias). Results of several studies in normal and hypertensive humans, and a few studies in animal models, are consistent with the notion that DA-1 agonists may be useful in preventing or treating ARF. Careful randomized prospective clinical trials of DA-1 agonists in human ARF are needed to test this hypothesis.

University of Miami Division of Clinical Pharmacology Therapeutic Rounds: ischemic renal disease

Ischemic renal disease (IRD) is defined as a significant reduction in glomerular filtration rate and/or loss of renal parenchyma caused by hemodynamically significant renal artery stenosis. IRD is a common and often overlooked clinical entity that presents in the setting of extrarenal arteriosclerotic vascular disease in older individuals with azotemia. IRD is an important cause of chronic renal failure and end-stage renal disease (ESRD), and many patients with a presumed diagnosis of hypertensive nephrosclerosis may actually have undiagnosed ischemic nephropathy as the cause of their ESRD. The primary reason for establishing the diagnosis of IRD is the hope that correction of a renal artery stenosis will lead to improvement of renal function or a delay in progression to ESRD. There are six typical clinical settings in which the clinician could suspect IRD: acute renal failure caused by the treatment of hypertension, especially with angiotensin-converting enzyme inhibitors; progressive azotemia in a patient with known renovascular hypertension; acute pulmonary edema superimposed on poorly controlled hypertension and renal failure; progressive azotemia in an elderly patient with refractory or severe hypertension; progressive azotemia in an elderly patient with evidence of atherosclerotic disease; and unexplained progressive azotemia in an elderly patient. It is important for the clinician to identify IRD, because IRD represents a potentially reversible cause of chronic renal failure in a hypertensive patient.

A numerical study of the stiffness of a sarcomere

Relatively recent experimental findings of the significant compliance of the thin (actin) and thick (myosin) filaments have brought into question a number of conclusions based on the assumption of perfect myofilament rigidity. A new model based on a discrete representation of the relevant structures was used to calculate the theoretical stiffness of a sarcomere with compliant myofilaments. Because of the discrete nature of the model, it can be applied to situations in which either the number of links between filaments is low (i.e. partial overlap or partial activation) or the spatial distribution of links is not uniform. The results of this model are discussed and compared to the predictions given by the previously published model by Ford et al. (Ford, L. E., Huxley, A. F. and Simmons, R. M., Journal of Physiology, 1981, 311, 219--249). Although it can be shown that both models give identical results for an infinite number of links, our model consistently predicts a stiffer sarcomere for partial overlap. The differences in the stiffness values as calculated by a model with rigid filaments, the continuous model by Ford et al. and the discrete model presented here would lead to differences in the interpretation of experimental results, especially in the case of partial overlap and partial activation. An explanation for the discrepancies between models is presented together with a way to correct the continuous model to approximate discrete model results.

Surrogate endpoints and renal protection: focus on microalbuminuria

End-stage renal disease (ESRD) is a major public health problem worldwide. The past decade has witnessed increased interest and investigative attention on therapeutic manoeuvres to retard the progression of renal disease. Reduction of albuminuria is regarded as a surrogate endpoint, because this phenomenon seems to be associated with preservation of GFR (principal endpoint) in diabetic nephropathy. Studies from our laboratory suggest that reduction in albuminuria during ACE inhibition constitutes a predictor of an attenuated rate of decline in GFR in early diabetic nephropathy. Because the rate of decline in kidney function is used to assess prognosis and the efficacy of therapy on progression of renal disease, a valid method for the determination of GFR is essential. During the last two decades, several radioactive and non-radioactive filtration markers have been validated and found to be both accurate and precise compared to inulin. Plasma clearance of such filtration markers is frequently applied in clinical trials in diabetic nephropathy because patients suffering from this complication frequently also suffer from diabetic cystopathy, precluding measurements of urine volume. Measurements of serum creatinine, creatinine clearance, calculated creatinine clearance by use of the Cockroft-Gault formula must all be regarded as surrogate measurements for glomerular filtration rate. Consequently, care must be taken to select appropriate filtration markers in order to rigorously evaluate therapeutic trials in progressive renal disease.

Calcium antagonists and the progression of chronic renal failure

End-stage renal disease, which signifies irreversible renal failure, constitutes a major and growing public health problem worldwide. The striking increase in end-stage renal disease has catalyzed clinical and investigative focus on pharmacologic interventions to retard progression to this condition. Increasing evidence indicates that some classes of antihypertensive medications may confer a greater effect than others in slowing progression of renal disease despite similar levels of blood pressure reduction. Substantive data indicate that angiotensin converting enzyme inhibition preferentially retards the progression of renal disease, primarily by protecting the injured kidney from hemodynamically mediated glomerular damage. Newer studies suggest that calcium antagonists also have diverse properties, which are independent of their renal microcirculatory effects that might afford renal protection.

Articular joint mechanics with biphasic cartilage layers under dynamic loading

The composition and amount of extracellular matrix produced by chondrocytes are thought to be influenced by the stress and strain states in the vicinity of the chondrocytes. During daily activities, such as walking and running, articular joints are loaded dynamically. In the present study, a solution is proposed to simulate the responses of a joint under dynamic loading. In order to show the characteristics of the proposed solution, numerical simulations were carried out, in which the contact radius, the relative approach displacement between the centers of the contacting bodies, or the contact force were controlled. As a result of the history-dependent material properties of the articular cartilage, the predicted parameters changed nonperiodically, when the controlled parameters varied periodically. For a constant load, the contact radius and the relative displacement between the contacting bodies were predicted to increase at decreasing rates. When the contact force was varied dynamically, the predicted mean values of the contact radius, the relative displacement between the contacting bodies, and the contact pressure at the center of the contact area depended on the amplitude and the duration of the loading. When the relative displacement between the contacting bodies was controlled, the amplitudes and the cycling frequency must be limited to avoid a loss of contact between the articular joint surfaces. The proposed solution is valid for a long but limited time period, the exact extent of which is yet to be determined. It can be used to simulate the effects associated with cartilage degeneration in diseases such as osteoarthritis.

Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues

The biphasic cartilage model proposed by Mow et al. (1980) has proven successful to capture the essential mechanical features of articular cartilage. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made. This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.

Nested expression and sequential downregulation of the Xenopus caudal genes along the anterior-posterior axis

Expression of the Xenopus Xcad-1 and Xcad-2 genes initiates during early gastrulation exhibiting a dorsoventral asymmetry in their domains of transcription. At mid-gastrulation the ventral preference becomes stronger and the caudal genes take up a posterior localization in their expression, which they will maintain until their downregulation along the dorsal midline. Comparison of the three Xenopus caudal genes revealed a temporal and spatial nested set of expression patterns. The transcription of the caudal genes is sequentially downregulated with the one expressed most caudally (Xcad-2) being shut down first, this sequence is most evident along the dorsal midline. This pattern of expression suggests a role for the caudal genes as posterior determinants along the anteroposterior axis. In chicken, mouse, man and Xenopus three members of the caudal family have been identified in the genome. Even though in Xenopus the Xcad-3 gene has been previously described, in order to obtain a better insight on the role of the caudal genes a comparative study of all three frog genes was performed.

New chart to evaluate weight faltering

A new chart was designed to aid accurate identification of weight faltering and failure to thrive. It provides guidance on the lower limits of expected weight gain for children, whatever their initial centile position. The chart's theoretical basis, the process of its construction, and its evaluation are described in this paper. Evaluation was by a self completion questionnaire, where respondents answered questions about a range of standardised growth patterns, plotted on old and new charts. Forty five health visitors, 28 general practitioner principals and registrars, and nine community paediatricians provided 328 chart ratings. These showed that the new format significantly increased the proportion of correctly rated charts (old: 45 (28%); new: 82 (51%)), with the greatest impact in severe cases. This suggests that the new chart improves the precision of judgments made about weight gain in infancy.

Lysophosphatidic acid and platelet-derived growth factor synergistically stimulate growth of cultured rat mesangial cells

Lysophosphatidic acid (LPA) is a structurally simple, platelet-derived phospholipid, capable of eliciting a variety of physiological responses. We have demonstrated previously that LPA elicited a marked contractile response in rat mesangial cells (Inoue CN, Forster HG, Epstein M. Circ Res 77:888-896, 1995). In the present study, we examined the potential of this vasoactive substance to induce mesangial cell proliferation. Serum-starved quiescent rat mesangial cells were incubated with either LPA or in combination with platelet-derived growth factor (PDGF). DNA synthesis was assessed by [3H]thymidine incorporation after 24 hr, and cell numbers were determined at 0, 4, and 7 days. LPA- (1 nM-30 microM) stimulated mesangial cell DNA synthesis in a dose-dependent manner. The DNA synthesis stimulated by PDGF (1-100 ng/ml) was characterized by a bell-shaped response curve with a maximum at 40 ng/ml PDGF. The ability of LPA (30 microM) to synergize PDGF was observed over the entire range of PDGF concentrations (1-100 ng/ml). Under optimal concentrations of LPA/PDGF (30 microM40 ng/ml, respectively), mesangial cells displayed a 67-fold increase in [3H]thymidine incorporation, and a 1.9-fold (Day 4) and 2.5-fold (Day 7) increase in cell number as compared with that of quiescent mesangial cells. With an in vitro assay with myelin basic protein as the substrate, both LPA and PDGF induced stimulation of mitogen-activated protein (MAP) kinase activity. In addition, LPA augmented PDGF-induced increase in MAP kinase activity. In summary, these results demonstrate that LPA is mitogenic alone and also acts synergistically in combination with PDGF to promote mesangial cell proliferation. We postulate that these actions of LPA have the potential to play a crucial role in the mitogenic response of mesangial cells seen in a wide array of inflammatory and thrombotic glomerular disorders.