One-year outcome of hip fracture patients admitted to a Singapore hospital: quality of life post-treatment

INTRODUCTION

A prospective and consecutive documentation of hip fracture care was performed. Outcomes, including quality of life, mortality, complication rates, were documented; and mobility, ambulatory status, freedom from pain and activities of daily living one year before and after treatment, were compared.

METHODS

We prospectively reviewed the medical records of 70 consecutive patients admitted to the Singapore General Hospital, following either a cervical or intertrochanteric femoral fracture from February 2004 to May 2004. Patients' progress was reviewed at one year post-treatment, and the EuroQOL was used to quantify the patients' quality of life. Description of any problems encountered was also recorded.

RESULTS

The follow-up rate at one year for the 70 patients described in this report was 98.6 percent. Mortality rate was 27.1 percent. Early complication rate was 5.7 percent. Outcome was satisfactory in all but two patients. Mortality for surgically-operated patients was 25.4 percent. About a quarter of the patients had excellent ambulatory status and 40.0 percent were able to walk independently. Eight percent suffered from falls after discharge, but no recurrence of hip fracture was recorded. None was re-admitted under suspicion of hip fracture. The average self-scoring system (EuroQOL) yielded an average of 66.6 out of 100.

CONCLUSION

Hip fractures can be treated surgically with good results and low early complication rates, without drastically affecting patients' quality of life.

From Trousseau to targeted therapy: new insights and innovations in thrombosis and cancer

Venous thromboembolism (VTE) commonly occurs in patients with malignant disease. At the 1997 ISTH meeting, cancer and thrombosis was discussed in a state-of-the-art symposium. Since then, there have been many new developments on this topic. Tumors, through expression of tissue factor can activate coagulation. Furthermore, local peritumor activation of coagulation may have important effects on the biology of cancer. A randomized trial has been conducted which evaluated extensive screening to detect underlying malignancy vs. no screening in patients presenting with idiopathic VTE. No statistically significant difference was detected in cancer-related mortality between the two groups. A trial has evaluated extended prophylaxis in patients undergoing surgery for abdominal malignancy. There was a statistically significant reduction in venographically detected deep vein thrombosis in favor of 4 weeks of treatment. In contrast, there is clearly a need for more information on the use of thromboprophylaxis in medical cancer patients. Low molecular weight heparin (LMWH) has replaced unfractionated heparin as the first line treatment in the majority of patients with acute VTE. Many cancer patients with acute VTE can be treated safely at home with subcutaneous LMWH without admission to hospital. The results of a recent trial demonstrated that long-term low molecular weight heparin administered over a 6-month period substantially reduced the rate of recurrent VTE compared with oral anticoagulant therapy with no increase in bleeding. Finally, the first trial specifically designed to evaluate the anticancer effect of long-term LMWH in cancer patients has been conducted and will no doubt stimulate future research.

Photopatch testing in seven cases of photosensitive drug eruptions

OBJECTIVE

The most important goal in the management of photosensitive drug eruptions, as in other types of drug eruptions is identification of the causative drugs to prevent reexposure to them.

CASE SUMMARIES

Seven patients whose lesions were mainly distributed on sun-exposed areas underwent laboratory tests, phototests, and photopatch tests with suspected drugs. Phototests were done with ultraviolet A (UVA), UVB, and visible light. Drugs used in the photopatch tests were usually prepared as 10% concentrations in petroleum base, which did not produce reactions in 10 control subjects, followed by irradiation of suberythema doses of UVA. Systemic provocation by oral administration of small doses of causative drugs with irradiation of suberythema doses of UVA was performed to confirm the results of skin tests in four patients. Two patients were not rechallenged with the causative drugs. None of the patients had systemic lupus erythematosus, porphyria, or pellagra. All showed positive reactions to photopatch testing. Systemic provocation confirmed the results of photopatch tests in four patients. The two patients who were not rechallenged had no recurrence of lesions. One patient ingested only one drug at the time of eruptions, and provocation or avoidance was not attempted. A photoallergic mechanism was considered in five cases.

CONCLUSIONS

Although there is no information about the appropriate concentrations or vehicles for suspected drugs, photopatch testing could be reliable for identification of causes of photosensitive drug eruptions. Besides piroxicam (a well-known photosensitizer) and carbamazepine, isoniazid and triflusal were identified as the causes of the reactions.

Treatment of venous thrombosis in the cancer patient

Venous thromboembolism is a common complication in patients with cancer. The management of deep vein thrombosis and pulmonary embolism can be a considerable challenge in patients with cancer. The cancer itself and associated treatments contribute to an ongoing thrombogenic stimulus, while cancer patients are thought to be at increased risk for anticoagulant-induced bleeding. Initial treatment of acute thromboembolism is with intravenous unfractionated heparin or subcutaneous low molecular weight heparin. Treatment at home with low molecular weight heparin is an attractive option in patients with malignant disease. Long-term treatment of acute venous thromboembolism has traditionally been with oral anticoagulants. However, the inconvenience and narrow therapeutic window of oral anticoagulants make such therapy unattractive and problematic in cancer patients. Low molecular weight heparins are being evaluated as an alternative for long-term therapy because their anticoagulant effects are more predictable and laboratory monitoring is unnecessary. Although many clinical issues remain unresolved in the treatment of cancer patients with venous thromboembolism, the future holds much promise as new antithrombotic agents, including factor Xa antagonists and oral thrombin inhibitors, are being tested in clinical trials.

Multicenter study of the frequency of contact allergy to gold

Gold sodium thiosulfate (GSTS) is reputed to be the most reliable gold antigen, but control studies are still required. Although Koreans have more varied sources of contact with gold, such as herbal medicines with gold coatings and indwelling gold acupuncture needles, no epidemiological studies have been performed. This study examined the frequency and sources of contact allergy to gold in South Korea by a multicenter study. Patch testing with 0.5% GSTS in pet. was conducted in 255 eczema patients and 58 control subjects. Results were observed at 21 days (D) to ensure there were no undetected late reactions in 54 observed patients and 47 controls. 8 (3.1%) of the 255 patients reacted positively to GSTS, including 1 with a late reaction. 1 of the 58 controls showed a positive reaction to GSTS on D4 with a negative reaction on D14. Clinical relevance was lacking in the patients with positive reactions. Unexpectedly, the above particular sources of gold contact gave rise to few allergic reactions in our patients.

Acute myocardial infarction after upper gastrointestinal gastroscopy

We describe a patient with gastric ulcer confirmed by upper gastrointestinal endoscopy who developed an acute Q wave myocardial infarction involving both the anterior and inferior wall shortly after the procedure. This life-threatening complication of gastroendoscopy was clearly demonstrated through studies of electrocardiogram, cardiac enzymes, echocardiogram and cardiac catherterization. We suggest that preventive measures should be implemented so that endoscopy can be performed under optimal conditions, especially for elderly patients with history of heart disease.

Treatment of venous thromboembolism in cancer patients

The management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients with cancer can be a clinical dilemma. Comorbid conditions, warfarin failure, difficult venous access, and a high bleeding risk are some of the factors that often complicate anticoagulant therapy in these patients. In addition, the use of central venous access devices is increasing but the optimal treatment of catheter-related thrombosis remains controversial. Unfractionated heparin (UFH) is the traditional standard for the initial treatment of venous thromboembolism (VTE) but low molecular weight heparins (LMWHs) have been shown to be equally safe and effective in hemodynamically stable patients. For long-term treatment or secondary prophylaxis, vitamin K antagonists remain the mainstay treatment. However, the inconvenience and narrow therapeutic window of oral anticoagulants make extended therapy unattractive and problematic. As a result, LMWHs are being evaluated as an alternative for long-term therapy. New antithrombotic agents are being tested in clinical trials and may have the potential to replace conventional treatment. The role of inferior vena cava filters in cancer patients remains ill defined but these devices remain the treatment of choice in patients with contraindications for anticoagulant therapy.

Induction of herpes simplex virus gB-specific cytotoxic T lymphocytes in TAP1-deficient mice by genetic immunization but not HSV infection

Loading of most endogenous peptides on major histocompatibility complex class I molecules is conditional on their transport into the endoplasmic reticulum (ER) by the peptide transporter TAP. We describe an HSV-2/1 cross-reactive cytotoxic T-cell (CTL) epitope that is processed in a TAP1-independent manner in vivo following immunization of TAP1-/- mice with naked DNA or a recombinant vaccinia virus. These data indicated that TAP1-independent processing of endogenous proteins is sufficient to prime CTLs in vivo. TAP1-independent processing of this epitope was not due to ER targeting by signal sequences and exogenous loading of MHC-I molecules and was not influenced by the amino acids flanking this epitope. In contrast, TAP1-/- mice infected with HSV-2 or HSV-2 mutants did not mount a CTL response against this epitope.

Like fibrin, (DD)E, the major degradation product of crosslinked fibrin, protects plasmin from inhibition by alpha2-antiplasmin

Plasmin generation is localized to the fibrin surface because tissue-type plasminogen activator (t-PA) and plasminogen bind to fibrin, an interaction that stimulates plasminogen activation over a hundred-fold. To ensure efficient fibrinolysis, plasmin bound to fibrin is protected from inhibition by alpha2-antiplasmin. (DD)E, a major soluble degradation product of cross-linked fibrin that is a potent stimulator of t-PA, compromises the fibrin-specificity of t-PA by promoting systemic activation of plasminogen. In this study we investigated whether (DD)E also protects plasmin from inhibition by alpha2-antiplasmin, facilitating degradation of this soluble t-PA effector. (DD)E and fibrin reduce the rate of plasmin inhibition by alpha2-antiplasmin by 5- and 10-fold, respectively. Kringle-dependent binding of plasmin to (DD)E and fibrin, with Kd values of 52 and 410 nM, respectively, contributes to the protective effect. When (DD)E is extensively degraded by plasmin, yielding uncomplexed fragment E and (DD), protection of plasmin from inhibition by alpha2-antiplasmin is attenuated. These studies indicate that (DD)E-bound plasmin, whose generation reflects the ability of (DD)E to stimulate plasminogen activation by t-PA, has the capacity to degrade (DD)E by virtue of its resistance to inhibition. This provides a mechanism to limit the concentration of (DD)E and maintain the fibrin-specificity of t-PA.

Left atrial and ventricular ball thrombi complicating rheumatic heart disease with combined mitral and aortic stenosis

A 42-year-old woman with chronic mitral stenosis was admitted for progressive dyspnea, palpitation, and weakness of lower extremities. Echocardiography revealed rheumatic, thickened, and stenotic mitral and aortic valves, and two free-floating ball thrombi were detected in the left atrium and ventricle, respectively. She died suddenly the next day, probably due to mitral or aortic outflow obstruction by the ball thrombi. We believe that the occurrence of free-floating ball thrombi in both the left atrium and left ventricle concomitantly has never been reported.

The pleasures and pains of distinct self-construals: the role of interdependence in regulatory focus

Regulatory focus theory distinguishes between self-regulatory processes that focus on promotion and prevention strategies for goal pursuit. Five studies provide support for the hypothesis that these strategies differ for individuals with distinct self-construals. Specifically, individuals with a dominant independent self-construal were predicted to place more emphasis on promotion-focused information, and those with a dominant interdependent self-construal on prevention-focused information. Support for this hypothesis was obtained for participants who scored high versus low on the Self-Construal Scale, participants who were presented with an independent versus interdependent situation, and participants from a Western versus Eastern culture. The influence of interdependence on regulatory focus was observed in both importance ratings of information and affective responses consistent with promotion or prevention focus.

Fixed drug eruptions. Incidence, recognition, and avoidance

Drug eruptions often have nonspecific clinical findings, and the evaluation of the probability of an eruption being a drug-induced event is difficult. A few types of drug eruption do not present such problems, and the fixed drug eruption is one of those whose clinical findings are specific enough to allow a diagnosis. The fixed drug eruption is a commonly reported type of drug eruption. The incidence of fixed drug eruptions has tended to increase, although the overall number of drug eruption cases has decreased. This is one of the reasons why fixed drug eruptions are familiar to dermatologists. The most characteristic findings of a fixed drug eruption are recurrence of similar lesions at the same sites and healing with residual hyperpigmentation. The residual hyperpigmentation serves as an indicator of site recognition. Diagnosis is not always easy; for example, as is the case for nonpigmenting fixed drug eruptions, which do not have any residual hyperpigmentation. The development of molecular biology may help to clarify the pathogenesis of fixed drug eruptions, but the reason for their recurrence on the same sites is still unknown. Identification of the causative drug or drugs is essential for the management of fixed drug eruptions, as it is for other drug eruptions. The causative drug or drugs and cross-reactants should be avoided to prevent recurrence. To date, rechallenge is the most reliable method of identifying causative drugs, but increasingly the use of skin tests has gained the attention of investigators. The validity and the problems of skin tests are discussed, and an approach to the clinical management of fixed drug eruptions is presented.

The pleasures and pains of distinct self-construals: the role of interdependence in regulatory focus

Regulatory focus theory distinguishes between self-regulatory processes that focus on promotion and prevention strategies for goal pursuit. Five studies provide support for the hypothesis that these strategies differ for individuals with distinct self-construals. Specifically, individuals with a dominant independent self-construal were predicted to place more emphasis on promotion-focused information, and those with a dominant interdependent self-construal on prevention-focused information. Support for this hypothesis was obtained for participants who scored high versus low on the Self-Construal Scale, participants who were presented with an independent versus interdependent situation, and participants from a Western versus Eastern culture. The influence of interdependence on regulatory focus was observed in both importance ratings of information and affective responses consistent with promotion or prevention focus.

Priming of hepatitis C virus-specific cytotoxic T lymphocytes in mice following portal vein injection of a liver-specific plasmid DNA

The immunology of hepatitis C virus (HCV) infection should be studied in the context of HCV antigen expression in the liver, because HCV primarily infects this organ. Indeed, the nature, function, and fate of T cells primed after antigen expression in the liver might differ from those primed when antigens are expressed systemically or in other organs, because the nature of the antigen-presenting cells (APCs) involved may be different. In addition, the normal liver contains a resident population of lymphocytes that differ from those present at other sites. Thus, we investigated whether HCV-specific CD8(+) cytotoxic T cells (CTLs) could be elicited following portal vein (PV) injection of plasmid DNA in mice whose hepatic veins were transiently occluded. We show that PV injection of mice with "naked" DNA expressing the HCV-NS5a protein, under the control of a liver-specific enhancer/promoter, resulted in NS5a expression in the liver and the priming of HCV-specific CTLs. These results suggested that such a model might be relevant to the study of HCV-specific immune responses primed during natural infection.

A novel putative transcription factor protein MYT2 that preferentially binds supercoiled DNA and induces DNA synthesis in quiescent cells

Myelin transcription factor 2 (MYT2), a putative transcription factor found in the human central nervous system, was cloned from an expression cDNA library from human T-cells. MYT2 shares weak similarity to bacterial type I topoisomerases and shares 63% sequence identity to a replicase from Leuconostoc mesenteroides. MYT2 preferentially binds supercoiled DNA (scDNA). Incubation of MYT2 and scDNA at or above equal molar ratios generated topoisomer-like patterns that were abolished by deproteination. Thus, MYT2 appears to relax scDNA via a non-enzymatic mechanism. The banding pattern of MYT2-scDNA complexes was shown to be quantisized, saturable and sequence-independent. Microinjection of MYT2 mRNA induced G(o) growth-arrested NIH 3T3 cells to enter the S phase of the cell cycle.

Jupiter: Aerosol Chemistry in the Polar Atmosphere

Aromatic compounds have been considered a likely candidate for enhanced aerosol formation in the polar region of Jupiter. We develop a new chemical model for aromatic compounds in the Jovian auroral thermosphere/ionosphere. The model is based on a previous model for hydrocarbon chemistry in the Jovian atmosphere and is constrained by observations from Voyager, Galileo, and the Infrared Space Observatory. Precipitation of energetic electrons provides the major energy source for the production of benzene and other heavier aromatic hydrocarbons. The maximum mixing ratio of benzene in the polar model is 2x10-9, a value that can be compared with the observed value of 2+2-1x10-9 in the north polar auroral region. Sufficient quantities of the higher ring species are produced so that their saturated vapor pressures are exceeded. Condensation of these molecules is expected to lead to aerosol formation.

Quantification of the number of cytotoxic T cells specific for an immunodominant HCV-specific CTL epitope primed by DNA immunization

Priming of strong cellular immune responses to hepatitis C (HCV) is thought to be important for eradication of infection. Although productive infection of HCV occurs only reproducibly in humans and chimpanzees, definition of HCV-specific T cell epitopes in mice is necessary to screen efficiently HCV vaccine strategies for their ability to prime cellular immune responses. Out of seven strains of mice screened for immunodominant CTL epitopes against HCV-1a Core, E2, NS5a and NS5b, only one epitope (p214K9) in only one mouse strain was identified. Enumeration of p214K9-specific CD8+ cells by flow cytometry revealed that the number of epitope specific CTL primed by 'naked' DNA immunization was lower than that reported during viral infection. The p214K9 epitope described here, combined with analysis of CTL responses by flow cytometry, should be instrumental in ranking various HCV vaccine strategies for their ability to prime CTL responses.

Management of venous thromboembolism in cancer patients

Venous thromboembolism is a common complication in patients with cancer. The management of deep-vein thrombosis and pulmonary embolism can be a considerable challenge in these patients. Diagnosing venous thrombosis requires objective testing, and noninvasive investigations may be less accurate in patients who have cancer than in those who do not. Treatment of acute venous thrombosis at home with low-molecular-weight heparin is an attractive option in patients with malignant disease, in whom quality of life is especially important. Comorbid conditions, warfarin resistance, difficult venous access, and a potentially high bleeding risk are some of the factors that often complicate the prolonged course of anticoagulant therapy needed in this group. In addition, the use of central venous catheters is increasing, but the optimal treatment of catheter-related thrombosis remains controversial. This article reviews the current diagnostic and treatment approaches to venous thromboembolism in patients with cancer and provides several clinical scenarios to illustrate and discuss some common management problems.

Placement of intravenous cannulae prior to ambulatory phlebectomy

BACKGROUND

Ambulatory phlebectomy (AP) is a popular outpatient procedure for the removal of varicose veins. One of the major obstacles of AP is the disappearance and shift of the veins to be removed when the patient is positioned horizontally.

OBJECTIVE

We aimed to verify the usefulness of preoperative placement of intravenous cannulae.

METHODS

Forty-three vein segments of four consecutive patients with varicose veins were treated by AP with preoperative placement of intravenous cannulae. The procedures including anesthesia, incision, and exteriorization of the veins were performed with intravenous cannula in situ. We compared the courses of cannula and preoperative conventional marking of the veins. The time spent with extracting a vein was also compared with that spent with conventional procedure.

RESULTS

The preoperative cannulation provides excellent fixation of varicose veins to their original position, at least at the puncture sites. The disagreement of courses between cannula and preoperative conventional marking was noticed in 47.8% of the vein segments from the knees and thighs, and in 15% from the lower legs. The time spent for extracting a vein was reduced by more than half with our method.

CONCLUSION

Intravenous cannulation prior to AP is a simple procedure, but significantly improves the technique of AP by more accurately guiding the site of anesthesia and incision.

Clinical utility of a rapid whole-blood D-dimer assay in patients with cancer who present with suspected acute deep venous thrombosis

BACKGROUND

Although D-dimer assays have high negative predictive values for the diagnosis of deep venous thrombosis, their accuracy in patients with cancer is uncertain.

OBJECTIVE

To compare the clinical utility of a whole-blood D-dimer assay for the diagnosis of deep venous thrombosis in patients with and those without cancer.

DESIGN

Retrospective analysis of three prospective studies.

SETTING

Two tertiary care hospitals.

PATIENTS

1068 consecutive outpatients with suspected deep venous thrombosis.

MEASUREMENTS

All patients underwent D-dimer testing and assessment with a priori diagnostic strategies that incorporated impedance plethysmography, compression ultrasonography, or contrast venography. Patients in whom deep venous thrombosis was not diagnosed initially were followed for 3 months for the development of thrombosis. Results of D-dimer testing were assessed according to the final diagnosis based on objective testing and clinical follow-up. Cancer status was identified at presentation.

RESULTS

The prevalence of deep venous thrombosis was 48.8% in 121 patients with cancer and 14.6% in 947 patients without cancer. Although the sensitivity of the D-dimer assay was similar in patients with and those without cancer (86.4% [95% CI, 75.0% to 94.0%] and 82.6% [CI, 75.2% to 88.5%], respectively), the specificity was significantly lower in patients with cancer (48.4% [CI, 35.5% to 61.4%] and 82.2% [CI, 79.4% to 84.8%]), as was the negative predictive value (78.9% [CI, 62.7% to 90.4%] and 96.5% [CI, 94.9% to 97.8%]). In contrast, the likelihood ratios of a negative test result (0.28 [CI, 0.14 to 0.56] and 0.21 [CI, 0.15 to 0.31]) did not differ significantly.

CONCLUSIONS

A negative D-dimer test result in patients with cancer does not reliably exclude deep venous thrombosis because the negative predictive value of the test is significantly lower in these patients than in patients without cancer.

The Venus flytrap of periplasmic binding proteins: an ancient protein module present in multiple drug receptors

Located between the inner and outer membranes of Gram-negative bacteria, periplasmic binding proteins (PBPs) scavenge or sense diverse nutrients in the environment by coupling to transporters or chemotaxis receptors in the inner membrane. Their three-dimensional structures have been deduced in atomic detail with the use of X-ray crystallography, both in the free and liganded state. PBPs consist of two large lobes that close around the bound ligand, resembling a Venus flytrap. This architecture is reiterated in transcriptional regulators, such as the lac repressors. In the process of evolution, genes encoding the PBPs have fused with genes for integral membrane proteins. Thus, diverse mammalian receptors contain extracellular ligand binding domains that are homologous to the PBPs; these include glutamate/glycine-gated ion channels such as the NMDA receptor, G protein-coupled receptors, including metabotropic glutamate, GABA-B, calcium sensing, and pheromone receptors, and atrial natriuretic peptide-guanylate cyclase receptors. Many of these receptors are promising drug targets. On the basis of homology to PBPs and a recently resolved crystal structure of the extracellular binding domain of a glutamate receptor ion channel, it is possible to construct three-dimensional models of their ligand binding domains. Together with the extensive information available on the mechanism of ligand binding to PBPs, such models can serve as a guide in drug discovery.

The thrombophilic state induced by therapeutic agents in the cancer patient

Multiple risk factors contribute to the hypercoagulable state in cancer patients. Antineoplastic therapy, including single- or multiagent chemotherapy, hormonal therapy, and hematopoietic growth factors, is an unavoidable and a significant precipitant of venous and arterial thromboses. The risk of thrombosis following cancer treatment also depends on the interaction between treatment agents, type and stage of cancer, and the presence of other risk factors for thrombosis such as advanced age, surgery, immobilization, and the use of central venous catheters. Therefore, although a causal role of cancer treatment in thrombosis is widely accepted, the pathogenic mechanisms are poorly understood and are difficult to investigate because of the multiple confounding factors that are involved. Alterations in coagulation factors, anticoagulant proteins, and endothelial damage have all been shown to occur following cytotoxic agents. The best-studied drugs with definite hypercoagulable effects are L-asparaginase and tamoxifen.

Treatment of venous thromboembolism in cancer patients

The occurrence of venous thromboembolism complicates the management of the patient with malignant disease because of the need for anticoagulant therapy. Cancer patients have an ongoing thrombotic stimulus due to the underlying cancer and its associated treatments, but are also considered to be at increased risk for anticoagulant-related bleeding. In recent years, the results of clinical trials have demonstrated the safety and efficacy of weight-adjusted subcutaneous low molecular weight heparin, administered at home, for patients with acute deep vein thrombosis. This approach is particularly attractive to patients with cancer where quality of life is an important consideration. There are no trials that specifically address the question of the duration of oral anticoagulant therapy in cancer patients. However, data can be extrapolated from trials evaluating the duration of oral anticoagulant therapy in other high-risk patients. Hence, cancer patients should continue oral anticoagulant therapy for as long as the cancer remains active (usually at least 6 months). There still remain a number of unanswered questions about the clinical management of thromboembolism in the cancer patient.

Contributions of polyol pathway to oxidative stress in diabetic cataract

There is strong evidence to show that diabetes is associated with increased oxidative stress. However, the source of this oxidative stress remains unclear. Using transgenic mice that overexpress aldose reductase (AR) in their lenses, we found that the flux of glucose through the polyol pathway is the major cause of hyperglycemic oxidative stress in this tissue. The substantial decrease in the level of reduced glutathione (GSH) with concomitant rise in the level of lipid peroxidation product malondialdehyde (MDA) in the lens of transgenic mice, but not in the nontransgenic mice, suggests that glucose autoxidation and nonenzymatic glycation do not contribute significantly to oxidative stress in diabetic lenses. AR reduction of glucose to sorbitol probably contributes to oxidative stress by depleting its cofactor NADPH, which is also required for the regeneration of GSH. Sorbitol dehydrogenase, the second enzyme in the polyol pathway that converts sorbitol to fructose, also contributes to oxidative stress, most likely because depletion of its cofactor NAD+ leads to more glucose being channeled through the polyol pathway. Despite a more than 100% increase of MDA, oxidative stress plays only a minor role in the development of cataract in this acute diabetic cataract model. However, chronic oxidative stress generated by the polyol pathway is likely to be an important contributing factor in the slow-developing diabetic cataract as well as in the development of other diabetic complications.--Lee, A. Y. W., Chung, S. S. M. Contributions of polyol pathway to oxidative stress in diabetic cataract. FASEB J. 13, 23-30 (1999)

Stereotype efficiency reconsidered: encoding flexibility under cognitive load?

According to the encoding flexibility model, stereotypes are efficient because they facilitate, in different ways, the encoding of both stereotype-consistent and stereotype-inconsistent information when capacity is low. Because stereotypical information is conceptually fluent, it may be easily understood, even when resources are scant. As a result, processing resources may shift from stereotypical toward counterstereotypical information, which is difficult to comprehend under such conditions. Thus, whereas inconsistent information receives greater attention (Experiments 1-3) and perceptual encoding (Experiment 4) when resources are depleted, the conceptual meaning of consistent information is extracted to a greater degree under such conditions (Experiment 5). Potential moderating roles of stereotype strength and perceiver motivations are discussed, as are the implications of these results for dual process models of stereotyping.

Conformational switching in an aspartic proteinase

The crystal structure of a catalytically inactive form of cathepsin D (CatDhi) has been obtained at pH 7.5. The N-terminal strand relocates by 30 A from its position in the interdomain beta-sheet and inserts into the active site cleft, effectively blocking substrate access. CatDhi has a five-stranded interdomain beta-sheet and resembles Intermediate 3, a hypothetical structure proposed to be transiently formed during proteolytic activation of the proenzyme precursor. Interconversion between active and inactive forms of CatD is reversible and may be regulated by an ionizable switch involving the carboxylate side chains of Glu 5, Glu 180, and Asp 187. Our findings provide a structural basis for the pH-dependent regulation of aspartic proteinase activity and suggest a novel mechanism for pH-dependent modulation of substrate specificity.

Stereotype efficiency reconsidered: encoding flexibility under cognitive load?

According to the encoding flexibility model, stereotypes are efficient because they facilitate, in different ways, the encoding of both stereotype-consistent and stereotype-inconsistent information when capacity is low. Because stereotypical information is conceptually fluent, it may be easily understood, even when resources are scant. As a result, processing resources may shift from stereotypical toward counterstereotypical information, which is difficult to comprehend under such conditions. Thus, whereas inconsistent information receives greater attention (Experiments 1-3) and perceptual encoding (Experiment 4) when resources are depleted, the conceptual meaning of consistent information is extracted to a greater degree under such conditions (Experiment 5). Potential moderating roles of stereotype strength and perceiver motivations are discussed, as are the implications of these results for dual process models of stereotyping.

Laboratory diagnosis of venous thromboembolism

Venous thromboembolism is a common medical condition in both out-patients and in-patients. Despite the development of non-invasive tests, the diagnosis of deep vein thrombosis and pulmonary embolism remains a clinical challenge. In an effort to improve diagnostic accuracy and to reduce the necessity of serial testing, laboratory markers of thrombin generation and fibrinolysis have been investigated as first-line screening tests. Although the majority of markers are elevated in acute thrombosis, D-dimer, a specific derivative of cross-linked fibrin, appears to have the most potential clinical utility. Accuracy studies and preliminary management trials suggest that rapid D-dimer enzyme-linked immunosorbent assays and the whole blood agglutination assay, SimpliRED D-dimer (Agen Biomedical, Brisbane, Australia), have strong potential as exclusionary tests in patients with suspected venous thrombosis.

Autologous epidermal grafting with PUVA-irradiated donor skin for the treatment of vitiligo

BACKGROUND

Epidermal autografting has been used to treat vitiligo. The pigmentation achieved at the recipient site can be variegated and incomplete compared with that of the surrounding normal skin, and sometimes remains that way for a fairly long time.

OBJECTIVE

We investigated whether the clinical results from epidermal autografting are related to a change in the number of melanocytes. This was performed by counting the number of melanocytes in the epidermis obtained from biopsy and suction with and without psoralen plus UVA (PUVA) exposure of the donor sites before grafting.

METHODS

The numbers of melanocytes in the epidermis were counted after staining with dopa. The epidermis from suction and biopsy was included. The biopsied specimen was treated with NaBr for dermo-epidermal separation before staining, whereas the epidermis obtained from suction was stained directly.

RESULTS

The epidermis obtained from suction contained 40-60% of the number of melanocytes found in the biopsied epidermis. Melanocytes around the hair follicles seemed to be omitted. Treatment with PUVA 10-21 times caused the number of melanocytes to increase by 1.5-2 times the normal level with a promising clinical result.

CONCLUSIONS

The preparation of donor sites with PUVA before the treatment of vitiligo by epidermal autografting induced an increased number of melanocytes and improved the clinical result.

Thermodynamics of a transition state analogue inhibitor binding to Escherichia coli chorismate mutase: probing the charge state of an active site residue and its role in inhibitor binding and catalysis

Electrostatic interactions play important roles in the catalysis of chorismate to prephenate by chorismate mutase. Mutation of Gln88 to glutamate in the monofunctional chorismate mutase from Escherichia coli results in an enzyme with a pH profile of activity significantly different from that of the wild type protein. To investigate whether the mutation alters the substrate binding process or the catalysis, we have directly determined the thermodynamic parameters of a transition state analogue inhibitor binding to the wild-type chorismate mutase and its Q88E mutant using isothermal titration calorimetry. The results demonstrate that solvent reorganization and hydrophobic interactions contribute the predominant free energy to inhibitor binding. The charge state of Glu88 in the Q88E mutant was experimentally determined and was shown to be protonated at pH 4.5 and ionized at pH 7.8, consistent with earlier hypotheses. Most surprisingly, inhibitor binding energetics do not exhibit significant pH dependency for both enzymes. Our findings indicate that the charge state of Glu88 has a small impact on inhibitor binding but plays an important role in the catalytic process.

Effects of sorbitol dehydrogenase deficiency on nerve conduction in experimental diabetic mice

In this report, we made use of sorbitol dehydrogenase (SDH)-deficient mutant mice (C57BL/LiA) to test whether there is a close correlation between the level of polyol accumulation and the degree of reduction in motor nerve conduction velocity (MNCV) associated with diabetes. The C57BL/LiA mouse has SDH deficiency due to a G-to-A mutation at the +1 position of intron 8, thus producing only aberrant SDH transcripts. These C57BL/LiA mice should have higher levels of polyol accumulation in the peripheral nerve because of the inability to further metabolize sorbitol to fructose. Here, we confirm by Western blot analysis and high-performance liquid chromatography that these mice lack SDH in the sciatic nerve and other various tissues, whereas normal mice possess SDH. These C57BL/LiA mice do not display any obvious phenotype that includes peripheral neuropathy in the normal laboratory environment and breed normally as described previously, although the tissues that normally contain SDH accumulate more sorbitol. This finding suggested that C57BL/LiA mouse strain is a valid model for studying the role in diabetic neuropathy of the polyol pathway, which consists of two enzymes-aldose reductase for converting glucose to sorbitol and SDH for converting sorbitol to fructose. Sorbitol levels in the sciatic nerve of diabetic C57BL/10N, nondiabetic, and diabetic C57BL/LiA mice were increased 4.3-, 16.6-, and 38.1-fold, respectively, above that of nondiabetic C57BL/10N. The fructose level in the sciatic nerve was increased 2.4-fold in diabetic C57BL/10N mice compared with that of nondiabetic and diabetic C57BL/LiA mice. Diabetic SDH-deficient mice showed an MNCV reduction similar in magnitude to that of diabetic C57BL/10N mice, despite greater nerve sorbitol accumulation and the lack of fructose in the former. The present data suggest that the levels of sorbitol and fructose in the sciatic nerve of mice do not correlate with the severity of MNCV deficit associated with diabetes.

Topical provocation in 31 cases of fixed drug eruption: change of causative drugs in 10 years

The pathomechanism of fixed drug eruption remains to be clarified, but patch testing has been used to determine the causative drug. 31 patients with fixed drug eruption were investigated to evaluate the diagnostic value of patch testing and to compare the causative drugs over the 10 years between the late 1980s and the late 1990s. 22 of them were given an oral provocation test to confirm the results of patch testing. A reaction showing definite infiltration, which occurred in 13 of 22 patients, reliably indicated the causative drug. In contrast, a patch test reaction without definite infiltration was not always correlated with systemic provocation. All except 1 patient found out their causative drug. The most frequent causative drug was sulfamethoxazole-trimethoprim in the late 1980s, but it had become chlormezanone 10 years later.

Two patients with isoniazid-induced photosensitive lichenoid eruptions confirmed by photopatch test

Causative agents of drug eruptions are frequently unknown, and skin tests with candidate drugs would be useful before systemic challenge. It remains to be clarified how phostosentive lichenoid drug eruptions are induced, but allergy, including delayed type allergy, has been suggested. Two patients who had taken anti-tuberculous drugs developed a lichenoid drug eruption, primarily on sun-exposed skin. Patch and photopatch tests were performed with each of the ingested drugs (10% in petrolatum). Photopatch tests to isoniazid (INH) were positive. These were confirmed by oral challenge followed by irradiation with UVA. In conclusion, photopatch tests facilitated identification of the causative drug in two patients with photosensitive lichenoid eruptions to INH.

Involvement of aldose reductase in naphthalene cataract

PURPOSE

The authors investigated the involvement of the enzyme aldose reductase (AR) in naphthalene cataract by using transgenic mice that overexpress AR.

METHODS

Lenses from nontransgenic mice and from transgenic lines CAR222 and CAR648, with different levels of AR, were cultured in medium containing naphthalene-1,2-dihydrodiol (ND) with or without AR inhibitor AL1576. The morphology and progression rate of ND-induced cataract in these lenses were compared.

RESULTS

Lenses from transgenic mice CAR222 and CAR648, but not their nontransgenic littermates, developed yellow pigment in the inner cortex when exposed to 50 microM ND, which was completely prevented by 0.2 mM AL1576. The yellow pigment developed faster and more intensely in the CAR648 lens, which has a higher AR level than CAR222. Under a high dose of 500 microM ND, both transgenic and wild-type mouse lenses developed ND-induced cataract, although the first sign of cataract was found in the outer cortex in transgenic lenses instead of the inner cortical region in wild-type lenses. In addition, the cataract was more severe and developed at a faster rate in transgenic mouse lenses. AL1576 showed only partial protection against the cataract induced by 500 microM ND.

CONCLUSIONS

The findings showed that the progression rate of ND-induced cataract correlated with the level of lens AR and ND, indicating that AR was the key enzyme for the metabolism of ND in the process of naphthalene cataract development.

Genetic immunization with adeno-associated virus vectors expressing herpes simplex virus type 2 glycoproteins B and D

Intramuscular injection of mice with an adeno-associated virus (AAV) vector expressing herpes simplex virus type 2 glycoprotein B led to the generation of both gB-specific major histocompatibility complex class I-restricted cytotoxic T lymphocytes and anti-gB antibody. AAV-mediated immunization was more potent than plasmid DNA or protein in generating antibody responses.