Stellenwert der Osteoporose in der traumatologischen Diagnostik

PURPOSE

To evaluate the current bone mineral density (BMD) distribution in elderly patients hospitalized due to traumatic hip fracture and to assess the necessity of concomitant pharmacotherapy of underlying osteoporosis.

MATERIALS AND METHODS

58 female patients > or = 50 years (mean 81 years) with proven hip fracture were included. The diagnosis of fracture was established either by conventional radiography (CR) or by computed tomography (CT). BMD was assessed prospectively by means of dual energy X-ray absorption (DXA) measurement of the lumbar spine and/or femoral neck. DXA data was routinely achieved by analysis of T- and Z-values of the BMD. Distribution of BMD was assessed. Results for both measurement sites were compared using T-test and Pearson correlation analysis.

RESULTS

56/58 patients with proven hip fracture received DXA of the lumbar spine, 51 DXA of the femoral neck. The mean BMD was 0.829 +/- 0.137 g/cm (2) (lumbar spine) and 0.451 +/- 0.126 g/cm (2) (femur). T-values were - 2.8 +/- 1.14 (lumbar spine) and - 3.53 +/- 0.97 (femur). Compared to the normal distribution (lumbar spine), 53 patients (94.6 %) had diminished BMD (T < or = - 1). Of these 15 (26.8 %) had osteopenia (T > - 2.5) and 38 (67.9 %) had osteoporosis (T < or = - 2.5) according to WHO definition. With respect to femoral bone measurement, all patients (100 %) had diminished BMD (T < or = - 1), 9 patients (17.6 %) had osteopenia (T > - 2.5) and 42 patients (82.4 %) had osteoporosis (T < or = - 2.5). Results for different measurement sites differed significantly and were weakly correlated.

CONCLUSION

This data indicate that diminished BMD in terms of osteopenia or osteoporosis is a frequent finding in hip fractures of elderly females. A large majority of these elderly patients therefore should be treated according to recent guidelines for treatment of osteoporosis. Our data indicate that this entity is potentially underdiagnosed and should be considered by radiologists as well as traumatologists.

[Osteoporosis in traumatology. Prevalence and management]

BACKGROUND

A fracture occurring in osteoporosis is a sentinel event but very rarely leads to bone mineral density (BMD) measurement or sufficient drug therapy. We designed an algorithm to evaluate BMD in older fracture patients and tested it for sustainability as well as acceptance among trauma/orthopedic surgeons.

METHODS

For a 1-year period a prospective BMD test was carried out in women older than 50 and men older than 75 years of age with fractures. The commencement and conduction of therapy during the initial hospital stay and rehabilitation were also analyzed.

RESULTS

From 228 members of the eligible age groups, 169 patients (74.1%) underwent BMD measurement. According to the WHO definition 71.6% showed reduced BMD in terms of osteoporosis and 24.3% in terms of osteopenia. In 84% therapy was started during initial hospital stay in 74.4% conducted during rehabilitation.

CONCLUSIONS

The vast majority of older patients exhibited reduced BMD as a substantial underlying cause of their fracture. A standardized clinical plan can help to identify and treat most patients with fragility fractures.

[Comparison of different stool tests for the detection of cancer of the colon]

BACKGROUND AND OBJECTIVE

Colonoscopy is the gold standard for the diagnosis of colonic neoplasia. Because of the low compliance, the discomfort of bowel preparation and the procedure itself and the (albeit small) risk of perforation or bleeding alternative procedures such as stool tests are being focused on.

PATIENTS AND METHODS

After informed consent stool samples of 116 patients (44 male, 72 female, median age 47 years), scheduled for colonoscopy and 22 patients (17 m, 5 f, 69 y) with known colorectal cancer stool samples were collected. The samples were investigated by three methods: a biochemical (Guajak) test for fecal occult blood, an immunological test for fecal occult blood and a test determining the dimer pyruvat kinase M2 (tumor M2-PK).

RESULTS

Sensitivity for detection of colorectal cancer or polyps was 27 % and 10 % for the biochemical test, 91 % and 19 % for the immunological test and 77 % and 48 % for the M2-PK-test, respectively. Specificity was 89 %, 94 % and 72 %, respectively.

CONCLUSIONS

Both methods for detection of occult blood had a similar specificity. The sensitivity of the immunological test for the detection of colorectal cancer was significantly higher. The M2-PK-test had a markedly lower specificity in diagnosing cancer. Because of the low sensitivity for polyps the usefulness of stool tests is questionable. Reducing incidence and mortality of colorectal cancer should be achieved by colonoscopy, a recommendation that requires specific communication to the public.

Mutation analysis of three genes encoding novel LKB1-interacting proteins, BRG1, STRADalpha, and MO25alpha, in Peutz-Jeghers syndrome

Mutations in LKB1 lead to Peutz–Jeghers syndrome (PJS). However, only a subset of PJS patients harbours LKB1 mutations. We performed a mutation analysis of three genes encoding novel LKB1-interacting proteins, BRG1, STRADα, and MO25α, in 28 LKB1-negative PJS patients. No disease-causing mutations were detected in the studied genes in PJS patients from different European populations.

Effects of transforming growth factor beta1 on bonelike tissue formation in three-dimensional cell culture. II: Osteoblastic differentiation

We supplemented rat marrow stromal cells (rMSCs) seeded on poly(L-lactic-co-glycolic acid) fiber meshes with transforming growth factor beta1 (TGF-beta1) to improve bone tissue formation for tissue engineering. Whereas our first study (Lieb, E., et al. Tissue Eng. 10, 1399-1413, 2004) investigated the effects of TGF-beta1 on matrix formation and mineralization, this second study focused on the differentiation of rMSCs to the osteoblastic phenotype in dynamic cell culture (orbital shaker). We assessed a series of bone markers to determine a dosing regimen for TGF-beta1 that enhances collagenous matrix formation and preserves or increases osteoblastic differentiation. Bone sialoprotein and osteonectin formation were investigated immunohistochemically and by RT-PCR. For alkaline phosphatase activity (ALP), we employed an enzyme assay. Osteocalcin was examined by RT-PCR as well as by an immunoassay. Whereas bone sialoprotein appeared to be dose-dependently increased in the immunochemistical stainings after supplementation with TGF-beta1, osteonectin remained unchanged. Both ALP activity and osteocalcin were suppressed by high doses of TGF-beta1, such as single doses of 10 ng/mL or four doses of 1 ng/mL added once a week. Considering the effects of TGF-beta1 both on differentiation and on matrix formation and mineralization, TGF-beta1 at 1 ng/mL, added once a week in the first 1 to 2 weeks, was selected as an effective dose to improve bonelike tissue formation in vitro.

[Low vitamin B12 levels in elderly patients cured within one week by oral cobalamin therapy]

OBJECTIVE

Non-dissociation of vitamin B12 from its carrying proteins is the most frequent cause of vitamin B12 deficiency in the elderly. The aim of this study was to determine the initial dose of oral cyanocobalamin that would correct the B12 vitamin deficiency within one week.

METHODS

This was an open, prospective, study on 30 elderly patients suffering from vitamin deficiency (B12 < 0.20 microg/L) induced by food-cobalamin malabsorption. Ten patients (group I) were treated with a daily dose of 1000 microg of oral cyanocobalamin (from D1 to D8), 10 (group II) with 1000 microg every other day (D1, D3, D5 and D7), 5 (group III) with 1000 microg every 4 days (D1 and D5) and 5 (group IV) with 1000 microg only on D1. The biological response was assessed by control measurement of vitamin B12 serum levels on the 8th day.

RESULTS

Mean vitamin B12 serum levels had significantly increased (p < 0.01) in groups I, II and III, but not in group IV. The dose-effect, assessed by the mean increase in vitamin B12 serum levels, was significantly greater (p < 0.05) in groups I (0.25 microg/L) and II (0.18 microg/L), than in groups III and IV (0.09 microg/L).

CONCLUSION

This prospective study shows that an oral dose of 1000 microg of cyanocobalamin every 4 days, which corresponds to 250 microg per day, was sufficient to correct B12 vitamin deficiency induced by food-cobalamin malabsorption within one week. However, initial doses of 1000 microg per day or every other day would be preferable because of the greater dose-effect with daily doses higher than 500 microg. A randomised study is warranted to validate these preliminary results.

Effects of Transforming Growth Factor β1 on Bonelike Tissue Formation in Three-Dimensional Cell Culture. I. Culture Conditions and Tissue Formation

Bone tissue engineering based on growing bone marrow stromal cells on poly(L-lactic-co-glycolic acid) fiber meshes suffers from limited matrix production and mineralization when the cells are cultured with the standard differentiation supplements (dexamethasone, beta-glycerophosphate, and ascorbic acid). To overcome this problem we included transforming growth factor beta1 (TGF-beta1), which is described as playing a key role in collagen type I formation, although its effect on mineralization is controversially discussed. The investigations focused on establishing culture conditions for the application of TGF-beta1 in three-dimensional cell culture and on the effects of different doses of TGF-beta1 (1-20 ng/mL) on bonelike extracellular matrix formation. Immunohistochemical staining showed that TGF-beta1 enhanced the formation of procollagen type I, collagen type I, and collagen type V, especially under dynamic culture conditions (orbital shaker). A long-term study confirmed positive effects on the formation of extracellular matrix, which penetrated the scaffold to a depth of 250 to 300 microm. Mineralization, qualified by scanning electron microscopy in combination with energy-dispersive X-ray analysis and evaluated by determination of the Ca2+ content per scaffold, was up to 1.7-fold increased by TGF-beta1 compared with the control. In conclusion, the growth factor TGF-beta1 seems to be effective in improving extracellular bonelike matrix formation in vitro.

Efficacy of short-term oral cobalamin therapy for the treatment of cobalamin deficiencies related to food-cobalamin malabsorption: a study of 30 patients

BACKGROUND

It has been suggested that oral cobalamin (vitamin (B12)) therapy may be an effective therapy for treating cobalamin deficiencies related to food-cobalamin malabsorption. However, the duration of this treatment was not determined.

PATIENTS AND METHOD

In an open-label, nonplacebo study, we studied 30 patients with established cobalamin deficiency related to food-cobalamin malabsorption, who received between 250 and 1000 microg of oral crystalline cyanocobalamin per day for at least 1 month.

ENDPOINTS

Blood counts, serum cobalamin and homocysteine levels were determined at baseline and during the first month of treatment.

RESULTS

During the first month of treatment, 87% of the patients normalized their serum cobalamin levels; 100% increased their serum cobalamin levels (mean increase, +167 pg/dl; P < 0.001 compared with baseline); 100% had evidence of medullary regeneration; 100% corrected their initial macrocytosis; and 54% corrected their anemia. All patients had increased hemoglobin levels (mean increase, +0.6 g/dl) and reticulocyte counts (mean increase, +35 x 10(6)/l) and decreased erythrocyte cell volume (mean decrease, 3 fl; all P < 0.05).

CONCLUSION

Our findings suggest that crystalline cyanocobalamin, 250-1000 microg/day, given orally for 1 month, may be an effective treatment for cobalamin deficiencies not related to pernicious anemia.

Partial rescue of the Dazl knockout mouse by the human DAZL gene

Y-chromosomal DAZ (deleted in azoospermia) and autosomal DAZ-like (DAZL) comprise a gene family involved in gametogenesis. Y-chromosomal and autosomal genes only co-exist in humans and old world monkeys, indicating that DAZ genes are a recent acquisition of the Y chromosome. In most mammals, the ancestral Dazl alone is sufficient to complete gametogenesis. It is not yet understood why humans and old world monkeys have a second set of genes that are apparently necessary for spermatogenesis, since deletions removing the Y-chromosomal DAZ are often associated with azoo- or oligospermia. We used transgenic mice carrying either human DAZL or human DAZ on a mouse Dazl null background to investigate the functions of the human homologues. Both transgenes enabled prophase spermatocytes to be produced, mainly of the leptonema/zygonema stage, but failed to promote differentiation into mid- to late pachytenes. The presence of human DAZL resulted in a larger amount of early germ cells compared with that observed in DAZ. The degree of rescue was independent of copy number, integration site or presence of the DAZ repeat region for the DAZ transgenes. These findings confirm that DAZL and DAZ can only substitute for early functions of the murine homologue resulting in the establishment of the germ cell population and partial progression into meiosis.

[Urinary tract infections due to wide spectrum beta lactamase producing enterobacteriaceae]

OBJECTIVES

The aim of this study was to specify the characteristics of enterobacterial urinary infections producing wide spectrum beta-lactamase (WSBL) and the management strategies for these patients infected in geriatric wards.

METHODS

The prevalence, bacteriological characteristics and treatment regimens of enterobacterial urinary infections producing WSBL, diagnosed in a geriatric department of internal medicine from May 1977 to April 2001, were studied retrospectively.

RESULTS

Sixty-six enterobacterial urinary infections producing WSBL were diagnosed, with 53 (80%) of them acquired in the ward. They represented 1.6% of admissions and concerned 24 men and 42 women (sex ratio: 0.57), with a mean age of 87 years. Their prevalence was of 20 in the 1st year, 11 in the 2nd, 9 in the third and 26 in the 4th year. The mean duration of hospitalization of infected patients was 4.5-fold longer (90 vs. 20 days) and the mortality rate 2-fold higher (32 vs. 14%). Enterobacter aerogenes were responsible for half (46%) of the WSBL urinary infections. The skin was invaded by enterobacteria in 67% and the feces in 57% of cases. More than one third of the urinary infections treated relapsed, and digestive decontamination was only efficient in half of the patients treated.

CONCLUSION

This 4-year study emphasizes the limits of antibiotherapy in eradicating WSBL-producing enterobacteria and the fact that only the strict respect of hygiene by all caregivers (isolation of patients exhibiting WSBL and washing-disinfection of the hands between each patient) limits the incidence of such infections.

Distribution and location of polycyclic aromatic hydrocarbons (PAHs) and PAH-degrading bacteria within polluted soil aggregates

A study was conducted to determine the location and distribution of PAH and PAH-degrading bacteria in different aggregate size fractions of an industrially polluted soil. The estimation of PAH-degrading bacteria using an MPN microplate technique indicated that these bacteria are most numerous in the aggregate size fractions corresponding to fine silt (2-20 microm) and clay (<2 microm) compared to larger fractions or unfractionated soil. PAH concentrations were also highest in the aggregate size fraction corresponding to fine silt. Similar results were found in a spiked soil (incubated for 6 months) with similar carbonated minerals. Transmission electron microscopy observations showed that the autochtonous PAH-degrading bacteria were embedded in the aggregates where PAHs were abundant. In spite of this extensive co-localisation PAH degradation was limited during 6 months incubation. This indicates that factors other than spatial distribution and PAH degrading ability control degradation rates. The fine silt fraction of the industrial soil had an elevated C/N ratio (35) compared to the clay fraction (C/N: 16). Thus the fraction which assumably had the highest specific surface area contained less PAH but similar numbers of PAH-degraders. N thus seem to play an important role in the long term, but as PAH degradation was low in fine size fractions, other sources/factors were probably limiting (easily degradable C, P org, O2 etc.). Based on these findings, soil particle organization and structure of soil aggregates appear to be important for the characterization of a polluted soil (localization and sequestration). Manipulations that modify aggregation in polluted soils could thus potentially influence the accessibility and biodegradability of PAHs.

[Candidemia in elderly people: apropos of 4 cases]

INTRODUCTION

Candidemia, principally affecting neutropenic patients in departments of oncohematology and frail patients in intensive care units, can also be observed in frail elderly people in geriatrics.

EXEGESIS

Authors report four observations of candidemia diagnosed in elderly dependent patients having several different diseases. Clinical sign was a persistent or recurrent fever after a wide-spectrum antibiotic therapy. Patients were treated by fluconazole leading to negative blood cultures in several days. Three out of four patients died within the weeks following antifungal therapy due to severity of associated diseases.

CONCLUSION

These observations show that a diagnosis of candidemia should be made when a persistent fever is observed in a frail elderly person. Fluconazole, as efficient as amphotericin B and well tolerated by elderly people, should be the first treatment of candidemia in non-neutropenic patients.

[Psychooncological aspects in the care of females in HNPCC families]

HNPCC families are characterized by a genetic predisposition for colorectal and other cancers. In Düsseldorf we pursue an interdisciplinary counselling approach (geneticists, psychologists and surgeons). Apart from the genetic counselling itself, special emphasis is placed on the benefits of surveillance and screening recommendations. In this pilot study we were interested in investigating if the counselled women had understood the increased risk of gynecological cancers and correspondingly underwent the intensified screening modalities. We selected the approach of a telefone interview and encountered broad acceptance for contacting persons this way. Affected women are better compliant to screening recommendations than women at risk. Both groups consider colonoscopy more strainful than gynecological surveillance. A regular transvaginal ultrasound is not performed in some 40 % of at risk women although 2/3 of them see their gynecologist in regular intervals. Given the support of gynecologists a higher rate of transvaginal ultrasound in women at risk should be achievable.

Apolipoprotein E inhibits serum-stimulated cell proliferation and enhances serum-independent cell proliferation

Independently of its role in lipid homeostasis, apolipoprotein E (apoE) inhibits cell proliferation. We compared the effects of apoE added to media (exogenous apoE) with the effects of stably expressed apoE (endogenous apoE) on cell proliferation. Exogenous and endogenous apoE increased population doubling times by 30-50% over a period of 14 days by prolonging the G(1) phase of the cell cycle. Exogenous and endogenous apoE also decreased serum-stimulated DNA synthesis by 30-50%. However, apoE did not cause cell cycle arrest; both apoE-treated and control cells achieved equivalent saturation densities at 14 days. Further analyses demonstrated that exogenous and endogenous apoE prevented activation of MAPK but not induction of c-fos expression in response to serum growth factors. Endogenous (but not exogenous) apoE altered serum concentration-dependent effects on proliferation. Whereas control (non-apoE-expressing) cell numbers increased with increasing serum concentrations (1.6-fold for every 2-fold increase in serum), apoE-expressing cell numbers did not differ as serum levels were raised from 2.5 to 10%. In addition, in low serum (0.1%), apoE-expressing cells had elevated DNA synthesis levels compared with control cells. We conclude that apoE does not simply inhibit cell proliferation; rather, the presence of apoE alters the response to and requirement for serum mitogens.

[Experiences with calcitonin treatment of patients with type I complex regional pain syndrome (CRPS I--Sudeck disease)]

PURPOSE/METHODS/PATIENTS: Calcitonin is a common treatment in patients suffering from Complex Regional Pain Syndrome Type 1 (CRPS I), although its effects are being controversially discussed. In a prospective study of 24 patients with CRPS I of the upper limb, we examined the tolerance of daily doses of 0.5 mg human calcitonin administered subcutaneously over 8 weeks. To assess the benefit of this therapy, the patients were clinically examined every second week. The results were compared to a consecutive group of 25 CRPS 1 patients who received only analgetics and physiotherapy.

RESULTS

With regard to all examined parameters (spontaneous pain, grip strength, edema, hand function, systematic temperature difference), the patients treated with calcitonin showed an improvement during the observation time. However, a statistically significant difference to the control group was calculated only for the reduction of the edema (P < 0.01). 83% (20/24 patients) of the calcitonin-treated patients suffered from severe, mostly gastroenterological side-effects. Hence therapy had to be discontinued in 3 cases (13%).

CONCLUSION

The therapy with calcitonin has the burden of numerous unpleasant side-effects and causes only a slight therapeutic improvement. Thus, calcitonin must only be prescribed with reservations for patients suffering from CRPS I.

Analysis of mouse beta-haptoglobin chain by lectin affinoblotting detection

Two different human mammary carcinoma cell lines were xenotransplanted into nude mice. Serum samples were obtained prior to and after transplantation and investigated by two-dimensional electrophoresis (2-DE). By comparison of these silver-stained patterns additional protein spots were detected resulting either from proteins secreted or shed by the tumor itself or from mouse proteins induced by the tumor or the transplantation procedure. One group of spots detectable in post-transplantation serum as well as in control serum after mock-transplantation but not in pretransplantation serum was microsequenced and identified as mouse beta-haptoglobin. The carbohydrate structures of beta-haptoglobin were characterized by two different immunochemical glycoprotein staining procedures to detect differential terminal glycan modifications.

[Clinical remission of an HLA B27-positive sacroiliitis on vegan diet]

BACKGROUND

Positive effects of fasting and vegan diet in patients with rheumatic diseases are reported in the literature.

MEDICAL HISTORY

We present a 33-year-old patient with double-sided HLA B27-positive sacroiliitis, which was diagnosed by magnetic resonance tomography. Since about 10 years he therefore had pain in the iliosacral region. Numerous sessions of physiotherapy, a cure treatment, and treatment with sulfasalazine and doxycycline were not effective. The patient was dependent on the daily intake of the nonsteroidal antirheumatics meloxicam 2 x 7.5 mg and ibuprofen 400-800 mg and the analgetic tramadol 50-150 mg, but evening and night pain and morning stiffness persisted under this treatment.

TREATMENT

We recommended a temporary vegan diet, i.e. to completely avoid animal fats and proteins.

COURSE

3-4 days after changing on vegan diet the complaints improved distinctly and persistently. After consumption of meat 6 weeks later, complaints worsened. Consequent vegan diet again resulted in significant improvement of the pain and morning stiffness. At follow-up 3 months after the initial contact, tramadol and ibuprofen intakes had been stopped, meloxicam had been reduced to 1 x 7.5 mg. The patient was almost completely free of complaints.

CONCLUSIONS

It was demonstrated that in a single case of sacroiliitis which was refractory to other treatment, vegan diet resulted in a convincingly improvement of complaints.

A synthetic heparin-mimicking polyanionic compound binds to the LDL receptor-related protein and inhibits vascular smooth muscle cell proliferation

A synthetic heparin-mimicking polyaromatic anionic compound RG-13577 (polymer of 4-hydroxyphenoxy acetic acid and formaldehyde ammonium salt, Mr approximately 5800) exhibits specific binding to vascular smooth muscle cells (SMCs) and inhibits their proliferative response to growth promoting factors. Receptor binding of (14)C-RG-13577 was efficiently competed by apolipoprotein E3 (apoE), lactoferrin, and the LRP (LDL receptor-related protein) receptor associated 39 kDa protein (RAP). Unlike cell surface binding of apoE, binding of RG-13577 to SMCs was not affected by heparin, heparan sulfate degrading enzymes, or low density lipoprotein (LDL). Moreover, wild-type and heparan sulfate-deficient Chinese hamster ovary (CHO) cells, as well as normal- and LDL receptor negative- human skin fibroblasts bind RG-13577, but not apoE, to a similar extent. On the other hand, homozygous mouse embryonic fibroblasts deficient in the LDL receptor-related protein (LRP) expressed a markedly reduced binding of RG-13577 as compared to normal mouse embryonic fibroblasts. These results indicate that RG-13577 and related compounds bind to the LRP receptor on the surface of vascular SMCs. Addition of lactoferrin to cultured SMCs protected the cells against the antiproliferative effect of compound RG-13577, suggesting that this inhibition is mediated by RG-13577 binding to LRP receptors on the SMC surface. Altogether, we have identified a series of synthetic polyaromatic anionic molecules that exhibit specific binding to LRP and thereby exert an antiproliferative effect on vascular SMCs. These compounds are applied to suppress SMC proliferation associated with restenosis and accelerated atherosclerosis.

Apolipoprotein E protects against bacterial lipopolysaccharide-induced lethality. A new therapeutic approach to treat gram-negative sepsis

Septic shock is the most common cause of death in intensive care units and no effective treatment is available at present. Lipopolysaccharide (LPS) is the primary mediator of Gram-negative sepsis by inducing the production of macrophage-derived cytokines. Previously, we showed that apolipoprotein E (apoE), an established modulator of lipid metabolism, can bind LPS, thereby redirecting LPS from macrophages to hepatocytes in vivo. We now report that intravenously administered LPS strongly increases the serum levels of apoE. In addition, apoE can prevent the LPS-induced production of cytokines and subsequent death in rodents. Finally, apoE-deficient mice show a significantly higher sensitivity toward LPS than control wild-type mice. These findings indicate that apoE may have a physiological role in the protection against sepsis, and recombinant apoE may be used therapeutically to protect against LPS-induced endotoxemia.

Plasma nitrate accumulation during the development of pacing-induced dilated cardiac myopathy in conscious dogs is due to renal impairment

Heart failure is associated with an increase in plasma nitrate and nitrite (NOx). To date there is still some controversy regarding the causes of nitrate accumulation during the development of heart failure. The goal of this study was to analyze the underlying mechanisms that cause accumulation of plasma nitrates during the development of heart failure in dogs. Dogs were chronically instrumented for measurement of hemodynamics and renal function. Hearts were paced initially at 210 bpm for 3 weeks and then at 240 until the development of heart failure. Hemodynamics, renal function, renal blood flow, arterial blood gases, hemoglobin, plasma and urine NOx levels, and creatinine levels were measured weekly. Heart failure was assessed by hemodynamic alterations, physical signs such as lethargy, ascites, cachexia, and postmortem evidence of cardiac hypertrophy. LVSP (from 127 +/- 3 to 106 +/- 3 mmHg), LV dP/dt (from 2658 +/- 173 to 1439 +/- 217 mmHg/s), MAP (from 101 +/- 1.9 to 83 +/- 1.8 mmHg) fell, whereas LVEDP tripled (from 6.4 +/- 0.9 to 20 +/- 2.6 mmHg), and heart rate rose (from 101 +/- 4.2 to 117 +/- 6.3 bpm), all changes P < 0.05. RBF (from 146 +/- 10 to 96 +/- 9.9 ml/min), urine output (V) (from 0.26 +/- 0.02 to 0.16 +/- 0.02 ml/min), GFR (from 63 +/- 1.8 to 49 +/- 2 ml/min), and Na excretion (from 45 +/- 4.5 to 14 +/- 4.6 microEq/min) all decreased (P < 0.05), whereas RVR increased (from 0.68 +/- 0.05 to 0.94 +/- 0.1 mmHg/ml/min). These changes took place during a rise in plasma NOx (from 3.7 +/- 0.5 to 16+/-3.3 microM), a decrease in urine NOx (from 33 +/- 9.9 to 8.1 +/- 4.9 microM), and a concurrent increase in NOx reabsorption (from 221 +/- 31 to 818 +/- 166 nmol/min). There was a direct correlation between the increase in plasma NOx levels and an increase in filtered load (r(2) = 0.97, P = 0.02), a negative correlation between NOx levels and NOx excretion (r(2) = 0.65 P < 0.09), and a direct correlation between plasma NOx levels and NOx reabsorption (r(2) = 0.97, P = 0.02). These results indicate that elevated plasma NOx during heart failure are most likely the result of an impairment of the renal function and not increased NOx production. Furthermore, without knowing changes in renal function the measurement of plasma NOx in and of itself is a meaningless index of NO formation.

Electrocardiographic exercise stress testing for cardiac risk assessment in patients undergoing noncardiac surgery

BACKGROUND

The value of exercise electrocardiography in the prediction of perioperative cardiac risk has yet to be defined. This study was performed to determine the predictive value of exercise electrocardiography as compared with clinical parameters and resting electrocardiography.

METHODS

A total of 204 patients at intermediate risk for cardiac complications prospectively underwent exercise electrocardiography before noncardiac surgery. Of these, 185 were included in the final evaluation. All patients underwent follow-up evaluation postoperatively by Holter monitoring for 2 days, daily 12-lead electrocardiogram, and creatine kinase, creatine kinase MB, and troponin-T measurements for 5 days. Cardiac events were defined as cardiac death, myocardial infarction, minor myocardial cell injury, unstable angina pectoris, congestive heart failure, and ventricular tachyarrhythmia. Potential risk factors for an adverse event were identified by univariate and multivariate logistic regression analysis.

RESULTS

Perioperative cardiac events were observed in 16 patients. There were 6 cases of myocardial infarction and 10 cases of myocardial cell injury. The multivariate correlates of adverse cardiac events were definite coronary artery disease (odds ratio, 8.8; 95% confidence interval [CI], 1.1--73.1; P = 0.04), major surgery (odds ratio, 4.7; 95% CI, 1.3--16.3; P = 0.02), reduced left ventricular performance (odds ratio, 2.0; 95% CI, 1.1--3.8; P = 0.03), and ST-segment depression of 0.1 mV or more in the exercise electrocardiogram (odds ratio, 5.2; 95% CI, 1.5--18.5; P = 0.01). A combination of clinical variables and exercise electrocardiography improved preoperative risk stratification.

CONCLUSIONS

This prospective study shows that a ST-segment depression of 0.1 mV or more in the exercise electrocardiogram is an independent predictor of perioperative cardiac complications.

Ineffective elimination of Leishmania major by inflammatory (MRP14-positive) subtype of monocytic cells

Myeloid-related protein (MRP) 14, an intracellular protein involved in calcium-dependent activation of myeloid cells, presents a differentiation marker for a subtype of macrophages. In experimental leishmaniasis, BALB/c mice succumb to visceral dissemination after infection with L. major, due to a Th2 cell response, while C57Bl/6 mice develop protective immunity associated with a Th1 cell response. We have previously shown that resistance in (C57Bl/6 mice was also associated with a significantly lower percentage of MRP14-positive cells in the infiltrate than in susceptible BALB/c mice. In C57Bl/6 mice, weekly injections of bone marrow (BM) cells enriched with MRP14-positive cells (d1 of culture) did not reverse, but prolonged the course of infection, associated with increased local parasite spread. In BALB/c mice a single dose of an antiphlogistic agent (dexamethasone or lipoxygenase inhibitor) was associated with reduction of infiltrating MRP14-positive cells and also with a decrease of parasite loads in footpads, lymph nodes as well as spleens, and with delayed progression of disease, Double labeling experiments in vitro revealed that at least 43.1% of MRP14-positive mononuclear cells in BM cultures (8h) had phagocytosed parasites after 4 h of co-incubation. Activation by IFN-gamma (20 U/ml) for 24h and 48h did not significantly reduce parasite load in these cells. In contrast, 77.0% of F4/80-positive macrophages (6d of culture) were infected with L. major parasites and these cells responded to activation with IFN-gamma (20 U/ml) with significant reduction of parasite load (25.3%). The protein MRP14 did not have an effect on parasite survival in vitro. Thus, the impaired capability of MRP14-positive cells to kill L. major upon stimulation may be one reason for the adverse course of infection observed with their increased appearance.

Immortalization of murine male germ cells at a discrete stage of differentiation by a novel directed promoter-based selection strategy

We developed a novel promoter-based selection strategy that could be used to produce cell lines representing sequential stages of spermatogenesis. The method is based on immortalization and subsequent targeted selection by using differentiation-specific promoter regions. As an example for this approach, a new murine germ cell line (GC-4spc) was established using a vector construct that contains the SV40 large T antigen and the neomycin phosphotransferase II gene under the control of the SV40 early promoter and a spermatocyte-specific promoter for human phosphoglycerate kinase 2, respectively. The GC-4spc was characterized as a cell line at the stage between preleptotene and early pachytene spermatocytes. Transcription of three germ cell-specific expressed genes, Pgk2, proacrosin, and the A-myb proto-oncogene, were detected in the GC-4spc cell line using reverse transcription-polymerase chain reaction. Furthermore, TSPY (human testis-specific protein, Y-encoded) and PGK2 (human phosphoglycerate kinase 2) promoter regions showed different transcriptional activities in the GC-4spc cell line compared with the spermatogonia-derived cell line GC-1spg. Thus, our strategy could be used for immortalization of cells at specific stages of differentiation, allowing production of a series of cultured cell lines representing sequential stages of differentiation in given cell lineages.

Structure and function of TSPY, the Y-chromosome gene coding for the "testis-specific protein"

The TSPY genes are arranged in clusters on the Y chromosome of many mammalian species. TSPY is believed to function in early spermatogenesis and is a candidate for GBY, the putative gonadoblastoma-inducing gene on the Y. The TSPY family forms part of a superfamily, TTSN, with autosomal representatives, highly conserved in mammals and beyond.

Organization and expression of rat Tspy

We have isolated both a full-length rat Tspy cDNA from testicular mRNA by rapid amplification of cDNA ends (RACE) and RT-PCR and a full-length rat Tspy gene from genomic DNA by PCR. In contrast to the mouse, where Tspy is present in a single copy and is apparently functionless, and to man and cattle, where TSPY is organized in a moderately repetitive cluster, the rat Tspy locus apparently consists of one complete functional and one truncated, probably nonfunctional, copy, coherently localized on Yp, as revealed by FISH analysis.

Murine and human TSPYL genes: novel members of the TSPY-SET-NAP1L1 family

Using expressed sequence tag (EST) sequence information, novel genes related to the Y chromosome gene family TSPY were isolated and characterized. Because of a significant homology to TSPY, the novel genes were designated TSPY-Like (TSPYL) and were assigned as new members of the TSPY-SET-NAP1L1 family. A human TSPYL gene was localized on chromosome 6 and a murine Tspyl gene was localized on chromosome 10. Expression of TSPYL was observed in all tissues investigated, as well as early onset during development. Both the human and murine Tspyl homologs lack introns over the entire region so far investigated and are thought to have arisen by an ancient retroposition event. Retroposition of Tspyl genes is supported by the isolation of a murine Tspyl pseudogene on chromosome 12 which also lacks intronic sequences, and by its observed proximity to an R element, a family of dispersed repetitive DNA.

The role of interleukin-4 in the regulation of sequential isotype switch from immunoglobulin G1 to immunoglobulin E antibody production

The immunoglobulin (Ig)E immune response against protein antigens is profoundly influenced by the antigen dose used for immunization. Whereas immunization of CBA/J mice with low antigen doses results in the production of large amounts of IgE antibody, priming with high antigen doses leads to only marginal IgE antibody production in animals. However, in vitro restimulation of spleen cells from mice primed with high antigen doses leads to considerable activation of IgE-producing B cells, which suggests that B cells primed for IgE antibody production do exist among spleen cells. We investigated the modalities of activation of these memory B cells. The data presented here reveal that the anamnestic IgE immune response in vitro is strictly dependent on the presence of IgG1-expressing B cells, which differentiate after a sequential isotype switch into IgE-producing plasma cells with the help of primed CD4+ T cells. The induction of IgE-producing plasma cells requires a cognate interaction between B cells and CD4+ T cells. Interleukin (IL)-4 seems not to be involved in this process, since IgE production in vitro is resistant to suppression by anti-IL-4 monoclonal antibody. Finally, we show that IgG1-expressing B cells represent a relevant memory cell population in vivo also, but in contrast to the in vitro situation the final differentiation into IgE-producing plasma cells is dependent on IL-4.

Endogenously expressed apolipoprotein E has different effects on cell lipid metabolism as compared to exogenous apolipoprotein E carried on triglyceride-rich particles

Apolipoprotein E (apoE) on model triglyceride-rich particles (TGRP) increases triglyceride (TG) utilization and cholesteryl ester (CE) hydrolysis, independent of its effect on enhancing particle uptake. We questioned whether, under physiological concentrations, endogenously expressed apoE has similar effects on cellular lipid metabolism as compared to exogenous apoE. J774 macrophages, which do not express apoE, were engineered to express endogenous apoE by transfection of human apoE3 cDNA expression constructs (E(+)) or control vectors (E(-)) into the cells. To compare the effects of exogenous apoE and endogenous apoE on TGRP uptake, cells were incubated with or without apoE associated with (3)H-cholesteryl ether-labeled TGRP. Exogenous apoE enhanced TGRP uptake in both E(-) and E(+) cells. E(-) cells displayed significantly higher TGRP uptake than E(+) cells. Sodium chlorate, which inhibits cell proteoglycan synthesis, markedly diminished differences in TGRP uptake between E(-) and E(+) cells, suggesting that endogenous apoE-proteoglycan interaction contributes to differences in uptake between the two cell types. Particle uptake by the LDL receptor, by the LDL receptor related protein, or by scavenger receptors were similar between E(-) and E(+) cells indicating that endogenous apoE expression does not have a general effect on endocytic pathways. Exogenous apoE carried on TGRP stimulated TG utilization and CE hydrolysis in both cell types. However, TG utilization and CE hydrolysis were not affected by endogenous apoE expression. In conclusion, macrophage expression of apoE has very different effects on TGRP metabolism than exogenously supplied apoE. The fluorescence microscopy results in this study showing that exogenous apoE and endogenous apoE were confined in separate cellular compartments support the hypothesis that these differences resulted from distinct intracellular trafficking pathways followed by exogenous apoE bound to TGRP as compared to endogenous cell-expressed apoE.

Extraintestinal polyps in Peutz-Jeghers syndrome: presentation of four cases and review of the literature. Deutsche Peutz-Jeghers-Studiengruppe

Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder characterized by hamartomatous polyps in the gastrointestinal tract and typical pigment lesions. Extraintestinal polyps have rarely been reported. Possible sites include the respiratory tract, urogenital tract, and gallbladder. We here describe four cases of extraintestinal polyps in PJS patients and review the literature on the need for operative therapy of extraintestinal polyps in PJS. Three nonrelated patients were examined who had PJS and polyps in the gallbladder; the fourth patient had PJS and recurrent choanal polyps. Surgery has so far been performed only for symptomatic polyps: one laparoscopic cholecystectomy and removal of the choanal polyps for recurrent infections of the respiratory tract. The remaining two patients reported no symptoms from the extraintestinal polyps. No malignant transformation was found in these patients, nor has such been reported in the literature on PJS. The frequent observation of this manifestation in our patients raises the question of clinical management: Is prophylactic surgery indicated? Since malignant transformation of PJS polyps in the intestine is extremely rare we see no reason for operative therapy as long as the polyps are small and asymptomatic. Regular sonographic controls are recommended since the risk of malignant transformation cannot be ruled out at present.

Specificities of heparin-binding sites from the amino-terminus and type 1 repeats of thrombospondin-1

Interactions of heparin with intact human thrombospondin-1 (TSP1) and with two heparin-binding fragments of TSP1 were characterized using chemically modified heparins, a vascular heparan sulfate proteoglycan, and a series of heparin oligosaccharides prepared by partial deaminative cleavage. The avidity of TSP1 binding increased with oligosaccharide size, with plateaus at 4 to 6 and at 8 to 10 monosaccharide units. The dependence on oligosaccharide size for binding to the recombinant amino-terminal heparin-binding domain of TSP1 was the same as that of the intact TSP1 molecule but differed from that of a synthetic heparin-binding peptide from the type 1 repeats, suggesting that the interaction between intact TSP1 and heparin is primarily mediated by the amino-terminal domain. Based on activities of chemically modified heparins, binding to TSP1 depended primarily on 2-N- and 6-O-sulfation of glucosamine and to a lesser degree on 2,3-O-sulfation and the carboxyl residues of the uronic acids. In contrast, all of these modifications were required for binding of heparin to the type 1 repeat peptides. Affinity purification of heparin octasaccharides on immobilized TSP1 type 1 repeat peptides revealed a preference for oligosaccharides containing the disaccharide sequence IdoA(2-OSO(3))alpha1-4-GlcNS(6-OSO(3)). Binding of these oligosaccharides to the peptide required the Trp residues. These data demonstrate that the heparin-binding specificities of intact TSP1 and peptides from the type 1 repeats overlap with that of basic fibroblast growth factor (FGF2) and are consistent with the ability of these TSP1-derived molecules to inhibit FGF2-stimulated angiogenesis.

Mice with Y chromosome deletion and reduced Rbm genes on a heterozygous Dazl1 null background mimic a human azoospermic factor phenotype

A subset of azoospermia or oligozoospermia patients have microdeletions in defined regions of their Y chromosome, namely the AZFa, b, and c regions. Candidate genes in humans that may cause the azoospermia factor (AZF) phenotype have been assigned to these regions and can include the DAZ and RBM genes. Part of the variability in the AZFc phenotype might be due to interaction between the effects of deleting the DAZ and RBM genes. We mimicked human deletions of RBM and DAZ in the mouse by crossing male mice with a deleted Y chromosome with a reduced number of Rbm genes (Y(d1)) to heterozygote Dazl1 null female mice to study the interaction of the Dazl1 and Rbm or other genes located in the Y(d1) deletion interval. Dazl-/+ Y(d1) animals showed a significant reduction in the sperm count (P < 0.001), an increase of abnormal sperm heads and prominent mid-piece defects of the tails compared to either mutation alone (P < 0.001). Hence, Dazl1 and the genes removed on the Y(d1) chromosome are active in different pathways contributing to different stages of spermatogenesis. Reduction of Dazl1 and Rbm genes as well as/or deletion of the Y chromosome in mice gives rise to a phenotype similar to the heterogeneous AZFc phenotype observed in humans.

Virus-specific cytotoxic T-lymphocyte responses select for amino-acid variation in simian immunodeficiency virus Env and Nef

Cytotoxic T-lymphocyte (CTL) responses to human immunodeficiency virus arise early after infection, but ultimately fail to prevent progression to AIDS. Human immunodeficiency virus may evade the CTL response by accumulating amino-acid replacements within CTL epitopes. We studied 10 CTL epitopes during the course of simian immunodeficiency virus disease progression in three related macaques. All 10 of these CTL epitopes accumulated amino-acid replacements and showed evidence of positive selection by the time the macaques died. Many of the amino-acid replacements in these epitopes reduced or eliminated major histocompatibility complex class I binding and/or CTL recognition. These findings strongly support the CTL 'escape' hypothesis.

Reduced coronary NO production in conscious dogs after the development of alloxan-induced diabetes

The role of nitric oxide (NO) in the control of coronary blood flow (CBF) during the development of diabetes is unknown. To study this, mongrel dogs were chronically instrumented using sterile techniques for measurements of systemic hemodynamics and CBF. With heart rate controlled (150 beats/min), veratrine (1-10 micrograms/kg) caused dose-dependent increases in CBF; e.g., 5 mirograms/kg of veratrine increased CBF by 57 +/- 7% from 41 +/- 1.3 ml/min (P < 0.05). The dogs developed diabetes 4-5 wk after injection of alloxan (40-60 mg/kg iv, blood glucose levels were 384 +/- 18 mg/dl). After diabetes the same doses of veratrine caused smaller increases in CBF; i.e., 5 micrograms/kg of veratrine increased CBF by 32 +/- 2% (P < 0.05 compared with control) from 28 +/- 4 ml/min. ACh- and adenosine-induced coronary vasodilation were reduced after diabetes as well. In anesthetized dogs after diabetes, vagal stimulation caused smaller increases in CBF. ACh and bradykinin caused smaller increases in NO(-)(2) production in coronary microvessels from diabetic dogs. Furthermore, despite the fact that mRNA for endothelial cell NO synthase from the aorta was increased twofold with the use of Northern blotting, the protein for aortic endothelial constitutive NO synthase was reduced by 66% after diabetes, as determined by Western blotting. Our results indicate that the NO-dependent coronary vasodilation by the Bezold-Jarisch reflex is impaired in conscious dogs after diabetes. The mechanism responsible for the impaired endothelium-dependent coronary vasodilation is most likely the decreased release of NO from the endothelium.

Adenosine and extracellular volume in radiocontrast media-induced nephropathy

Renal hemodynamic changes could play a key role in radiocontrast media-induced nephropathy (RCIN), although the pathophysiological mechanisms are unclear. We investigated the role of adenosine in RCIN caused by sodium diatrizoate (Urografin, 3 ml/kg) in nitro-L-Arg methyl ester (L-NAME)-hypertensive rats in different hydration states [eight weeks of L-NAME (50 mg/liter) in drinking water; high or low sodium intake for the last two weeks]. In clearance experiments under thiobutabarbital anesthesia in these previously mentioned animals, glomerular filtration rate (GFR), renal blood flow (RBF), and mean arterial pressure (MAP) were measured in the presence or absence of the adenosine A1-receptor antagonist 8-cyclopropyl-1,3-dipropylxanthine (DPCPX, 100 microg/kg bolus plus 10 microg/kg/hr). DPCPX or pretreatment did not change control hemodynamics. Contrast medium caused GFR and RBF to fall significantly in volume-depleted rats (from 0.29 +/- 0.02 to 0.21 +/- 0.02 ml/min/100 g and 5.4 +/- 0.3 to 4.0 +/- 0.4 ml/min, respectively) without change in MAP. In volume-expanded rats, changes were not significant (0.25 +/- 0.01 to 0.24 +/- 0.02 ml/min/100 g and 5.6 +/- 0.3 to 5.3 +/- 0.4 ml/min, respectively). In the volume-depleted rats, changes were prevented by DPCPX (0.27 +/- 0.02 to 0.24 +/- 0.02 ml/min/100 g and 4.8 +/- 0.1 to 5.0 +/- 0.1 ml/min, respectively). The acute hemodynamic effects elicited by contrast medium in L-NAME hypertensive rats thus can be prevented by volume expansion. Adenosine, via A1-receptors, contributes to the adverse effects of contrast media.

Effective therapy for hepatic M. Osler with systemic hypercirculation by ligation of the hepatic artery and subsequent liver transplantation

Hereditary hemorrhagic teleangiectasia, or M. Osler (Osler-Weber-Rendu disease), is an autosomal dominant, systemic fibrovascular dysplasia. This may lead to increased liver blood flow from arteriovenous fistulas. A 45-year-old woman with a known M. Osler was admitted for liver transplantation. On admission, exertional dyspnea was the predominant symptom. Radiological investigations revealed multiple intrahepatic arteriovenous fistulas and consecutive high-output heart failure. Laboratory findings revealed remarkably elevated bilirubin and alkaline phosphatase. To alleviate the high-output cardiac failure, the hepatic artery was ligated. Fourteen months later, the patient presented again with increased levels of bilirubin and recurrent bleeding episodes from esophageal varices grade IV. The patient underwent liver transplantation and post-transplant recovery was excellent. A hyperdynamic circulatory state due to a hepatic M. Osler has been treated in several cases by ligation or embolization of the hepatic artery. This procedure, however, is recommended only for patients with normal liver function and carries a considerably risk of bile duct necrosis.

Role of nitric oxide in the control of renal oxygen consumption and the regulation of chemical work in the kidney

Inhibition of NO synthesis has recently been shown to increase oxygen extraction in vivo, and NO has been proposed to play a significant role in the regulation of oxygen consumption by both skeletal and cardiac muscle in vivo and in vitro. It was our aim to determine whether NO also has such a role in the kidney, a tissue with a relatively low basal oxygen extraction. In chronically instrumented conscious dogs, administration of an inhibitor of NO synthase, nitro-L-arginine (NLA, 30 mg/kg i.v.), caused a maintained increase in mean arterial pressure and renal vascular resistance and a decrease in heart rate (all P<0.05). At 60 minutes, urine flow rate and glomerular flow rate decreased by 44+/-12% and 45+/-7%, respectively; moreover, the amount of sodium reabsorbed fell from 16+/-1.7 to 8.5+/-1.1 mmol/min (all P<0.05). At this time, oxygen uptake and extraction increased markedly by 115+/-37% and 102+/-34%, respectively (P<0.05). Oxygen consumption also significantly increased from 4.5+/-0.6 to 7.1+/-0.9 mL O2/min. Most important, the ratio of oxygen consumption to sodium reabsorbed increased dramatically from 0.33+/-0.07 to 0.75+/-0.11 mL O2/mmol Na+ (P<0.05), suggesting a reduction in renal efficiency for transporting sodium. In vitro, both a NO-donating agent and the NO synthase-stimulating agonist bradykinin significantly decreased both cortical and medullary renal oxygen consumption. In conclusion, NO plays a role in maintaining a balance between oxygen consumption and sodium reabsorption, the major ATP-consuming process in the kidney, in conscious dogs, and NO can inhibit mitochondrial oxygen consumption in canine renal slices in vitro.

Molecular cloning and characterization of P47, a novel boar sperm-associated zona pellucida-binding protein homologous to a family of mammalian secretory proteins

P47, a peripherally associated 47-kDa protein of porcine spermatozoa, was identified by affinity chromatography in the fraction of solubilized plasma membrane proteins bound to immobilized porcine zona pellucida glycoproteins. N-terminal and internal amino acid sequences revealed structural similarity between P47 and rat O-acetyl ganglioside synthase, bovine mammary gland protein (MGP)57/53 and mouse milk fat globule protein E8-polypeptides of unknown function secreted by mammary gland epithelial cells in both species. A polyclonal antibody directed against bovine MGP57/53 displayed cross-reactivity with P47. Indirect immunofluorescence analysis located porcine P47 on the acrosomal cap of testicular sperm and on sperm recovered along different sections of the ductus epididymidis, as well as on swim-up and in vitro-capacitated sperm. Porcine P47 was demonstrated on sperm bound to the zona pellucida of a homologous oocyte. Western blot analysis identified P47 (or MGP57/53) homologous proteins in porcine and human milk. Like the sperm-associated protein, porcine milk P47 possesses affinity for isolated, biotinylated sow oocyte zona pellucida glycoproteins. Reverse transcription-polymerase chain reaction was used to isolate P47 homologous cDNAs from porcine testis and mammary gland tissues as well as from bovine, mouse, and human testis. P47 proteins deduced from these cDNA sequences showed 60-100% amino acid sequence identity. These proteins display a mosaic structure organized into two N-terminal, tandemly arranged epidermal growth factor (EGF)-like domains followed by a region with similarity to C1 and C2 domains found in blood clotting factors V and VII. The second EGF-like domain contains an arginine-glycine-aspartic acid sequence, a motif often found in integrin receptor ligands. P47-like proteins are not expressed solely in testicular and mammary gland tissues. Northern blot analysis showed that P47 mRNA is transcribed in several porcine and bovine tissues. These data indicate a potential role for boar sperm-associated P47 in membrane remodeling and/or as a zona pellucida binding protein.