Incidence and symptoms of clinically manifest rotator cuff lesions

A clinical study of 200 unselected elderly subjects with an average age of 78 years living in retirement homes was performed to determine the prevalence of clinically manifest rotator cuff tears and the relevance of the tear for daily life. A comprehensive questionnaire was performed and the examination included the UCLA- and Constant-shoulder assessment scales and a multitude of special tests. The criteria for clinical diagnosis of a rotator cuff tear were a positive Jobe-test, diminished external rotation, a positive zero-degree-abduction test, the drop arm sign, pseudoparalysis and atrophy. By these criteria we found 28 (7%) rotator cuff tears in 25 people. There were 15 women and 10 men and the mean age of symptom onset was 55 years. Eleven craftsmen, 7 office workers and 7 housewives met our criteria for rotator cuff tears. Pain was present in 22 shoulders. Moderate weakness was found in 2 people and severe weakness in 22. In 20 people the range of motion was severely reduced and in 8 moderately reduced. Activities of daily living were impaired in all affected subjects. Eight people reported onset of symptoms after trauma. Patients with clinically diagnosed rotator cuff tears scored an average of 13 points in the UCLA-shoulder assessment scales and 40 points in the Constant-shoulder assessment scales. In conclusion rotator cuff may be symptomatic only in some people. Probably more anatomic than symptomatic rotator cuff tears exist, and it can be supposed that physical activities may be one possible reason for clinically relevant tears.

[Treatment modalities in infected knee alloarthroplasties]

PURPOSE

The purpose of this study was to present and to evaluate different treatment options in the infected knee alloarthroplasty.

METHODS

We followed 47 infected knee alloarthroplasties with a mean follow-up of 62 months which were surgically treated by different techniques. There were 20 cases with early infection (< or = 12 months) and 27 cases with late infections (> 12 months).

RESULTS

In 10 patients a two stage exchange of the implant were undertaken. In 6 of those 10 cases the infection could be successfully treated. 30 patients underwent an arthrodesis, two of those after an unsuccessful exchange procedure. In this group only in two patients the infection was not managed successfully. 28 of the patients with an arthrodesis showed a good result of the fusion side. One case was only debrided and in 8 cases bony and soft tissue damage lead to amputation. The HSS-score showed an excellent results in 5.3%, a good result in 21%, a fair result in 26.3% and a poor results in 47.4% of the cases. Comparable distribution was documented with the Hungerford-score. Patients with a stable and painless fusion showed a comparable functional outcome to those patients with a new replacement.

CONCLUSION

Revision of an infected knee implant is best managed by a two stage procedure and can lead to a good functional result. Fusion is indicated in cases with bad bony and soft tissue situation. A solid arthrodesis gives a painfree and stable extremity.

Proprioceptive function in knees with and without total knee arthroplasty

The goal of this study was to evaluate the differences in angle reproduction capability after nonconstrained posterior cruciate ligament retaining total knee arthroplasty after a follow-up time of 63.9 months compared with the healthy contralateral leg and a control group. In 28 total knee arthroplasty patients (mean age, 65.7 yr) and 25 control subjects (mean age, 55.7 yr), 16 measurements were made between 0 degrees and 90 degrees in 30 degree steps. The leg was positioned by the examiner and then relaxed; afterward, the subject was asked to reproduce the original position. Each measurement was made with the patient or control being blindfolded and not blindfolded to assess the influence of visual control. We found significant differences in total knee arthroplasty patients in contrast to healthy subjects. Without visual control, the mean deviation of the total knee arthroplasty group starting with a 0 degree angle was 7.7+/-5.9 degrees and 4.6+/-4.7 degrees for the healthy subjects. With visual control, the mean deviation in the patient group was 11+/-7.5 degrees, and in the control group, it was 7.2+/-5.0 degrees. Total knee arthroplasty patients did not show significant differences between the operated on and the contralateral knee. Also, in the total knee arthroplasty group, significant differences could not be found comparing reproduction with and without visual control and comparing both starting positions. In the control group, significant differences could be found comparing visual and nonvisual control in the 60 degree angle. The comparison between the 30 and 60 degree repositioning from both 0 and 90 degree starting positions showed a significant difference in the 60 degree angle. In summary, reduced proprioceptive capabilities are present after knee arthroplasty in both the operated on and the contralateral leg in our study group. Postoperative complaints can perhaps be explained by a loss of proprioceptive capabilities, especially at the 60 degree angle. The operative technique should involve special care of ligaments and muscles to preserve stability and receptors as well. Rehabilitation should pay more attention to the remaining receptors.

Effects of ions on adenosine binding and enzyme activity of purified S-adenosylhomocysteine hydrolase from bovine kidney

The present investigation was undertaken to determine the effect of various ions on the characteristics of S-adenosylhomocysteine (SAH) hydrolase from bovine kidney. The binding sites of [3H]-adenosine to purified SAH hydrolase were not influenced by phosphate, magnesium, potassium, sodium, chloride or calcium ions at physiological cytosolic concentrations. To test whether NAD+ in the SAH hydrolase is essential for adenosine binding, we prepared the apoenzyme by removing NAD+ with ammonium sulfate. The resulting apoenzyme did not exhibit any [3H]-adenosine binding. Since the apoenzyme was enzymatically inactive, it is suggested that adenosine binds to the active site and not to an allosteric site of the intact enzyme. The kinetics of the hydrolysis and the synthesis of SAH catalyzed by the enzyme SAH hydrolase were measured in the presence and absence of phosphate and magnesium. Phosphate increased the Vmax for both synthesis and hydrolysis. However, only the affinity of adenosine for SAH synthesis was significantly enhanced from 10.1+/-1.3 microM to 5.4+/-0.5 microM by phosphate. This effect was already maximal at a phosphate concentration of 1 mM. All other tested ions were without effect on the enzyme activity. Our results show that phosphate at physiological concentrations shifts the thermodynamic equilibrium of SAH hydrolase in the direction of SAH synthesis. These findings imply that SAH-sensitive transmethylation reactions are inhibited during renal hypoxia when intracellular levels of phosphate, adenosine, and SAH are elevated.

Human D3 dopamine receptor in the medulloblastoma TE671 cell line: cross-talk between D1 and D3 receptors

In search of a cell line in which the D3 dopamine receptor is expressed endogenously, we found that the neuron-derived human medulloblastoma cell line TE671 expresses the human D3 (hD3) and D1 (hD1) receptor, but neither the D2 or D4 receptors. Exposure of TE671 cells to the D3 agonist 7-OH-DPAT (DPAT), or to the D1 agonist SKF-38393 (SKF) increased the expression of hD3 or hD1 mRNA, respectively. Moreover, whereas DPAT had no effect on hD1 mRNA levels, stimulating the cells with SKF caused an increase in both hD1 and hD3 transcript levels. These results suggest (i) that following ligand stimulation, hD3 and hD1 receptors are upregulated to enhance their own receptor expression, and (ii) that upregulation of hD1 receptor transcripts leads to a stimulation of the hD3 dopamine receptor transcripts.

Functional hierarchy between two OSE2 elements in the control of osteocalcin gene expression in vivo

Osteocalcin gene expression is initiated perinatally and is restricted to mature osteoblasts and odontoblasts. Because their pattern of expression is highly restricted, the osteocalcin genes are excellent tools to study osteoblast-specific gene expression. To define the mechanisms of osteocalcin cell-specific gene expression in vivo, we generated transgenic mice harboring deletion mutants of the promoter region of OG2, one of the mouse osteocalcin genes. We show here that only 647 base pairs of this promoter are sufficient to confer cell-specific and time-specific expression to a reporter gene in vivo. This promoter fragment contains two copies of OSE2. This osteoblast-specific cis-acting element binds Osf2, a recently characterized osteoblast-specific transcription factor (Ducy, P., Zhang, R., Geoffroy, V., Ridall, A. L., and Karsenty, G. (1997) Cell 89, 747-754). We also demonstrate that the proximal OSE2 element is critical to confer an osteoblast-specific, developmentally regulated pattern of expression to a reporter gene. The other OSE2 element, located more upstream and presenting a lower affinity for Osf2, affects only weakly OG2 promoter activity. These data demonstrate the crucial role of Osf2 in controlling osteocalcin gene expression. Since osteocalcin synthesis is a hallmark of the differentiated osteoblast phenotype, these results suggest that, beyond its developmental function, Osf2 is also required for the maintenance of the osteoblast phenotype postnatally.

Dissociation between bone resorption and bone formation in osteopenic transgenic mice

Bone mass is maintained constant in vertebrates through bone remodeling (BR). BR is characterized by osteoclastic resorption of preexisting bone followed by de novo bone formation by osteoblasts. This sequence of events and the fact that bone mass remains constant in physiological situation lead to the assumption that resorption and formation are regulated by each other during BR. Recent evidence shows that cells of the osteoblastic lineage are involved in osteoclast differentiation. However, the existence of a functional link between the two activities, formation and resorption, has never been shown in vivo. To define the role of bone formation in the control of bone resorption, we generated an inducible osteoblast ablation mouse model. These mice developed a reversible osteopenia. Functional analyses showed that in the absence of bone formation, bone resorption continued to occur normally, leading to an osteoporosis of controllable severity, whose appearance could be prevented by an antiresorptive agent. This study establishes that bone formation and/or bone mass do not control the extent of bone resorption in vivo.

Importance of a flexible hinge near the motor domain in kinesin-driven motility

Conventional kinesin is a molecular motor consisting of an N-terminal catalytic motor domain, an extended stalk and a small globular C-terminus. Whereas the structure and function of the catalytic motor domain has been investigated, little is known about the function of domains outside the globular head. A short coiled-coil region adjacent to the motor domain, termed the neck, is known to be important for dimerization and may be required for kinesin processivity. We now provide evidence that a helix-disrupting hinge region (hinge 1) that separates the neck from the first extended coiled-coil of the stalk plays an essential role in basic motor activity. A fast fungal kinesin from Syncephalastrum racemosum was used for these studies. Deletion, substitution by a coiled-coil and truncation of the hinge 1 region all reduce motor speed and uncouple ATP turnover from gliding velocity. Insertion of hinge 1 regions from two conventional kinesins, Nkin and DmKHC, fully restores motor activity, whereas insertion of putative flexible linkers of other proteins does not, suggesting that hinge 1 regions of conventional kinesins can functionally replace each other. We suggest that this region is essential for kinesin movement in its promotion of chemo-mechanical coupling of the two heads and therefore the functional motor domain should be redefined to include not only the catalytic head but also the adjacent neck and hinge 1 domains.

A novel distal enhancer confers chorionic expression on the human renin gene

Renin catalyzes the rate-limiting step of the renin-angiotensin system, which regulates blood pressure and electrolyte homeostasis. To determine cell-specific human renin gene control elements, the transcriptional activity of promoter regions up to position -8876 was studied in renin-expressing cells. A positive regulatory region conferring approximately 57-fold higher transcriptional activity to the human renin gene promoter in chorionic cells was identified between nucleotides -5777 and -5552. It had the orientation-independent activity typical of classical enhancers. It also conferred approximately 59-fold higher transcriptional levels from the heterologous simian virus 40 (SV40) promoter in chorionic cells and approximately 6-fold higher transcriptional levels in Calu-6 and As4.1 cells, whereas no effect was measured in non-renin-expressing cells. DNase I footprinting showed that this enhancer contains three binding sites for chorionic cell nuclear extracts. Functional analysis suggested that the activity of the enhancer is regulated by differential mechanisms in the three renin-expressing cells involving a complex arrangement of AP-1 motifs binding cell-specific members of the basic leucine zipper family of transcription factors. Thus, our results demonstrate that this enhancer plays a key role in the expression of the human renin gene in the chorion and may also be involved in its regulated expression in other tissues.

Disruption of the dopamine D3 receptor gene produces renin-dependent hypertension

Since dopamine receptors are important in the regulation of renal and cardiovascular function, we studied the cardiovascular consequences of the disruption of the D3 receptor, a member of the family of D2-like receptors, expressed in renal proximal tubules and juxtaglomerular cells. Systolic and diastolic blood pressures were higher (approximately 20 mmHg) in heterozygous and homozygous than in wild-type mice. An acute saline load increased urine flow rate and sodium excretion to a similar extent in wild-type and heterozygous mice but the increase was attenuated in homozygous mice. Renal renin activity was much greater in homozygous than in wild-type mice; values for heterozygous mice were intermediate. Blockade of angiotensin II subtype-1 receptors decreased systolic blood pressure for a longer duration in mutant than in wild-type mice. Thus, disruption of the D3 receptor increases renal renin production and produces renal sodium retention and renin-dependent hypertension.

Functional characterization of mongoose nicotinic acetylcholine receptor alpha-subunit: resistance to alpha-bungarotoxin and high sensitivity to acetylcholine

The mongoose is resistant to snake neurotoxins. The mongoose muscle nicotinic acetylcholine receptor (AChR) alpha-subunit contains a number of mutations in the ligand-binding domain and exhibits poor binding of alpha-bungarotoxin (alpha-BTX). We characterized the functional properties of a hybrid (alpha-mongoose/beta gamma delta-rat) AChR. Hybrid AChRs, expressed in Xenopus oocytes, respond to acetylcholine with depolarizing current, the mean maximal amplitude of which was greater than that mediated by the rat AChR. The IC50 of alpha-BTX to the hybrid AChR was 200-fold greater than that of the rat, suggesting much lower affinity for the toxin. Hybrid AChRs exhibited an apparent higher rate of desensitization and higher affinity for ACh (EC50 1.3 vs. 23.3 microM for the rat AChR). Hence, changes in the ligand-binding domain of AChR not only affect the binding properties of the receptor, but also result in marked changes in the characteristics of the current.

Construction and characterization of an isogenic slt-ii deletion mutant of enterohemorrhagic Escherichia coli

Enterohemorrhagic Escherichia coli (EHEC) produces Shiga-like toxins (SLT), potent protein synthesis inhibitors. To further dissect the role of SLT-II in the course of disease, we have constructed E. coli TUV86-2, an isogenic SLT-II-negative mutant of EHEC strain 86-24. The slt-ii gene was inactivated by suicide vector mutagenesis. We also isolated derivatives of strain 86-24 that were cured of the phage carrying the toxin genes.

[Changes in crystallinity by sterilization and processing of ultrahigh molecular polyethylene used in endoprosthetics]

PURPOSE OF THE STUDY

We wanted to analyze crystallinity changes during sterilization in raw and in UHMWPE components for total joint arthroplasty manufactured.

MATERIALS AND METHODS

To analyze the crystallinity DSC measurements and to determine the relative crystallinity infrared spectroscopy was performed. The DSC measurements were based on a comparison between the melting enthalpy of one known material to the unknown material.

RESULTS

The raw manufactured non-sterilized sample showed a value for the DSC-measured crystallinity of 55.5%; the sample after gamma-sterilization without air was 56.0%, and with air 56.5%. The crystallinity after ethylene-oxide sterilization was 57.7% and after autoclavation 57.9%. The manufacturing time from the raw to the arthroplasty part showed some what different results. The average crystallinity of the samples differed between 55.4% and 61.6%. The best results were achieved in ETO-sterilized samples and one gamma-sterilized sample without air. The highest values were seen for the Hylamer.

CONCLUSION

In summary, the best values for crystallinity were seen in both raw and completed arthroplasty products with ETO sterilization. For medical use cancerogenous factors must be excluded. Gamma-sterilization without air can be accepted as well. Increasing the crystallinity too much can lead to more wear debris.

The mongoose acetylcholine receptor alpha-subunit: analysis of glycosylation and alpha-bungarotoxin binding

The mongoose AChR alpha-subunit has been cloned and shown to be highly homologous to other AChR alpha-subunits, with only six differences in amino acid residues at positions that are conserved in animal species that bind alpha-bungarotoxin (alpha-BTX). Four of these six substitutions cluster in the ligand binding site, and one of them, Asn-187, forms a consensus N-glycosylation site. The mongoose glycosylated alpha-subunit has a higher apparent molecular mass than that of the rat glycosylated alpha-subunit, probably resulting from the additional glycosylation at Asn-187 of the mongoose subunit. The in vitro translated mongoose alpha-subunit, in a glycosylated or non-glycosylated form, does not bind alpha-BTX, indicating that lack of alpha-BTX binding can be achieved also in the absence of glycosylation.

Ischemic hepatitis: clinical and laboratory observations of 34 patients

Ischemic hepatitis, a relatively infrequent disorder occurring in 0.16% to 0.50% of patients admitted to medical intensive care units, often follows episodes of hypotension or acute heart failure. Investigating the clinical characteristics of patients with ischemic hepatitis may add to our understanding of the pathogenesis and significance of this syndrome. We therefore conducted a retrospective analysis of 34 patients to examine the possible contribution of the various baseline characteristics to the severity of the hepatic damage. In all patients liver disease was unexpected and in some, liver dysfunction dominated the clinical picture. All patients had high serum glutamic pyruvic transaminase (SGPT) and lactic dehydrogenase (LDH) levels (mean +/- SE, 2073 +/- 255 international units and 6085 +/- 748 international units, respectively). The mean SGPT/LDH ratio was 0.34. Most patients had coagulopathy with a prolonged prothrombin time (mean +/- SE, 5.86 +/- 1.37 international normalized ratio [INR]). The most common diagnosis on admission was respiratory distress secondary to various causes. Before the development of the hepatic dysfunction, respiratory failure and hypoxemia were observed in 68% of the patients, whereas hypotension was observed in only 38%. More than 90% of the patients had three or more associated comorbid conditions. The most frequent of these were left heart failure (88.2%), right heart failure (67.6%), chronic obstructive lung disease (58.8%), and chronic renal failure (55.9%). During the acute episode, more than 90% of the patients had transient deterioration of their renal functions. Hypoglycemia was noted in 11 patients (32.4%), and the glucose level was inversely correlated with the SGPT level (r = -0.43, p = 0.01). Stepwise multiple regression analysis showed that left heart failure, systolic blood pressure lower than 90 mm Hg, and female gender, together, accounted for 34% of the variance of the peak SGPT levels (p = 0.002). Fourteen (41.2%) patients died during the 3-month follow-up period, but none from the hepatic injury. None of the clinical or laboratory parameters measured predicted mortality. Clearly, ischemic hepatitis is associated with a high risk of death. The characteristic patients are those with multiple underlying systemic diseases and conditions, especially those with left heart failure. Liver function test results and levels of liver enzymes should be monitored in these patients, particularly when they are admitted for respiratory deterioration and episodes of hypotension.

The protein kinase N (PKN) gene PRKCL1/Prkcl1 maps to human chromosome 19p12-p13.1 and mouse chromosome 8 with close linkage to the myodystrophy (myd) mutation

Protein kinase N (PKN) is a fatty acid- and Rho-activated serine/threonine protein kinase involved in the regulation of cell motility by association with cytoskeletal components such as neurofilament and alpha-actinin. We determined the chromosomal location of the human PKN gene PRKCL1 by fluorescence in situ hybridization and by radiation hybrid mapping. The corresponding mouse gene Prkcl1 was mapped by segregation analysis. We found by FISH that PRKCL1 is localized to chromosome 19p12-p13.1 and, more precisely, by radiation hybrid mapping, about 11 cR from EST WI-6344 in subband 19p12. Prkcl1 maps to mouse chromosome 8 between D8Mit6 and junb. This region of mouse Chr 8 shows a scrambled syntenic conservation to human chromosomes 4q, 8p, and 19p. As the mouse mutation myodystrophy myd has been mapped to the same region, Prkcl1 is a candidate gene for myd.

The endogenous insulin-like growth factor system in radiocontrast nephropathy

The response of insulin-like growth factor (IGF) I in acute renal failure was evaluated in a model of radiocontrast nephropathy associated with selective necrosis of medullary thick ascending limbs. In brief, rats were administered radiocontrast medium or vehicle injections for controls after combined inhibition of prostanoids and nitric oxide. Twenty-four hours after the insult, tissue mRNAs for IGF-I, the IGF-I receptor, and IGF-binding proteins (IGFBP) 1 and 3 were assayed in cortex, medulla, and liver by solution hybridization-RNase protection assay, and IGFBPs were measured in serum and tissue by Western ligand blotting. Cortical IGF-1 increased, whereas medullary IGF-I mRNA decreased. Renal IGFBPs decreased, whereas IGFBP-1 mRNA increased. The IGF system in the liver was unchanged. We conclude that general changes in renal IGFBPs in this experimental model of acute renal failure might increase the level of cortical IGF-I in a way that could modulate medullary recovery.

Is Hylamer adequate for use in alloarthroplasties?

In the present study ultrahigh molecular weight polyethylene (UHMWPE) implants from different manufactures were evaluated by differential scanning calorimetry (DSC), infrared spectroscopy (IRS) and wide-angle X-ray scattering (WAXS). With DSC measurements the crystallinity of all evaluated implants ranged between 58.2% and 73.2%. The highest crystallinity was documented in Hylamer with 73.2%. These results were checked and confirmed by infrared spectroscopy. According to WAXS studies Hylamer had an orthorhomboid phase as well as a monocline phase. After remelting the orthorhomboid phase was no longer detectable. We do not recommend using UHMWPE implants which have been secondarily modified. The product Hylamer clearly demonstrates how the original crystal structure of UHMWPE can be altered. The described changes in Hylamer implants will probably lead to an increased failure rate.

Modulation of the anti-acetylcholine receptor response and experimental autoimmune myasthenia gravis by recombinant fragments of the acetylcholine receptor

Myasthenia gravis (MG) is a neuromuscular disorder of man caused by a humoral response to the acetylcholine receptor (AChR). Most of the antibodies in MG and in experimental autoimmune myasthenia gravis (EAMG) are directed to the extracellular portion of the AChR alpha subunit, and within it, primarily to the main immunogenic region (MIR). We have cloned and expressed recombinant fragments, corresponding to the entire extracellular domain of the AChR alpha subunit (H alpha1-210), and to portions of it that encompass either the MIR (H alpha1-121) or the ligand binding site of AChR (H alpha122-210), and studied their ability to interfere with the immunopathological anti-AChR response in vitro and in vivo. All fragments were expressed as fusion proteins with glutathione S-transferase. Fragments H alpha1-121 and H alpha1-210 protected AChR in TE671 cells against accelerated degradation induced by the anti-MIR monoclonal antibody (mAb)198 in a dose-dependent manner. Moreover, these fragments had a similar effect on the antigenic modulation of AChR by other anti-MIR mAb and by polyclonal rat anti-AChR antibodies. Fragments H alpha1-121 and H alpha1-210 were also able to modulate in vivo muscle AChR loss and development of clinical symptoms of EAMG, passively transferred to rats by mAb 198. Fragment H alpha122-210 did not have such a protective activity. Our results suggest that the appropriate recombinant fragments of the human AChR may be employed in the future for antigen-specific therapy of myasthenia.

Development and characterization of antibodies directed against the mouse D4 dopamine receptor

Polyclonal antibodies against the mouse D4 dopamine receptor have been developed in order to investigate the anatomical localization of this receptor in the mouse brain. Two antibodies were generated against specific peptides corresponding to predicted extracellular and intracellular regions of the D4 protein. Specificity of these antibodies was demonstrated on human embryonic kidney 293 (HEK 293) cells transfected with different dopamine receptor subtypes; immunoreactivity was detected only in cells transfected with the mouse D4 dopamine receptor cDNA. Following in vitro transcription/translation of the mouse D4 cDNA, a single protein band of 36 kDa was selectively immunoprecipitated with the anti-D4 antibodies. The antibodies also detected a single protein of 36 kDa in Western blot of HEK 293 cells transiently transfected with the mouse D4 receptor. These antibodies were able to detect the D4 receptor in several regions of the mouse brain. In the regions examined, D4 immunoreactivity was found in neurones located in layers II-VI of the frontal and piriform cortices, with the highest concentration in layer II; in scattered neurones in the caudate putamen and in larger neurones in the globus pallidus. In all experiments, both antibodies exhibit the same specificity, and all immunoreactivity could be abolished by preincubation with the corresponding peptide antigen.