Comprehensive ocular and systemic pharmacokinetics of dexamethasone after subconjunctival and intravenous injections in rabbits

Even though subconjunctival injections are used in clinics, their quantitative pharmacokinetics has not been studied systematically. For this purpose, we evaluated the ocular and plasma pharmacokinetics of subconjunctival dexamethasone in rabbits. Intravenous injection was also given to enable a better understanding of the systemic pharmacokinetics. Dexamethasone concentrations in plasma (after subconjunctival and intravenous injections) and four ocular tissues (iris-ciliary body, aqueous humour, neural retina and vitreous) were analysed using LC-MS/MS. Population pharmacokinetic modelling for plasma data from both injection routes were used, and for first time the constant rate of absorption of dexamethasone from the subconjunctival space into plasma was estimated (ka,plasma = 0.043 min-1, i.e. absorption half-life of 17.3 min). Non-compartmental analysis was used for the ocular data analysis and resulting in ocular drug exposure of iris-ciliary body (AUC0-∞= 41984 min·ng/g) > neural retina (AUC0-∞= 25511 min·ng/g) > vitreous (AUC0-∞= 7319 min·ng/mL) > aqueous humour (AUC0-∞= 6146 min·ng/mL). The absolute bioavailability values after subconjunctival injection, reported for the first time, were 0.74 % in aqueous humour (comparable to topical dexamethasone suspensions), and 0.30 % in vitreous humour (estimated to be higher than in topical administration). These novel and comprehensive pharmacokinetic data provide valuable information on the potential for exploiting this route in ocular drug development for treating both, anterior and posterior segment ocular diseases. Moreover, the new generated dexamethasone-parameters are a step-forward in building predictive pharmacokinetic models to support the design of new subconjunctival dexamethasone formulations, which may sustain drug effect for longer period of time.

Barcode lipids for absolute quantitation of liposomes in ocular tissues

Lipid-based drug formulations are promising systems for improving delivery of drugs to ocular tissues, such as retina. To develop lipid-based systems further, an improved understanding of their pharmacokinetics is required, but high-quality in vivo experiments require a large number of animals, raising ethical and economic questions. In order to expedite in vivo kinetic testing of lipid-based systems, we propose a barcode approach that is based on barcoding liposomes with non-endogenous lipids. We developed and evaluated a liquid-chromatography-mass spectrometry method to quantify many liposomes simultaneously in aqueous humor, vitreous, and neural retina at higher than ±20% precision and accuracy. Furthermore, we showed in vivo suitability of the method in pharmacokinetic evaluation of six different liposomes after their simultaneous injection into the rat vitreal cavity. We calculated pharmacokinetic parameters in vitreous and aqueous humor, quantified liposome concentrations in the retina, and quantitated retinal distribution of the liposomes in the rats. Compared to individual injections of the liposome formulations, the barcode-based study design enabled reduction of animal numbers from 72 to 12. We believe that the proposed approach is reliable and will reduce and refine ocular pharmacokinetic experiments with liposomes and other lipid-based systems.

Quantitative intravitreal pharmacokinetics in mouse as a step towards inter-species translation

Although mouse models are widely used in retinal drug development, pharmacokinetics in mouse eye is poorly understood. In this study, we applied non-invasive in vivo fluorophotometry to study pharmacokinetics of intravitreal fluorescein sodium (molecular weight 0.38 kDa) and fluorescein isothiocyanate-dextran (FD-150; molecular weight 150 kDa) in mice. Intravitreal half-lives of fluorescein and FD-150 in mouse eyes were 0.53 ± 0.06 h and 2.61 ± 0.86 h, respectively. These values are 8-230 times shorter than the elimination half-lives of similar compounds in the human vitreous. The apparent volumes of distribution in the mouse vitreous were close to the anatomical volume of the mouse vitreous (FD-150, 5.1 μl; fluorescein, 9.6 μl). Dose scaling factors were calculated from mouse to rat, rabbit, monkey and human translation. Based on pharmacokinetic modelling and compound concentrations in the vitreous and anterior chamber, fluorescein is mainly eliminated posteriorly across blood-retina barrier, but FD-150 is cleared via aqueous humour outflow. The results of this study improve the knowledge of intravitreal pharmacokinetics in mouse and facilitate inter-species scaling in ocular drug development.

Intravitreal CendR peptides target laser-induced choroidal neovascularization sites in mice

Choroidal neovascularization (CNV) is a common ocular pathology that may be associated in a variety of eye diseases. Although intravitreal injection treatment of anti-vascular endothelial growth factor (anti-VEGF) drugs shows significant clinical benefits in CNV treatment, the limitations of the current therapy need to be addressed. The aim of our study was to investigate the potential utility of three C-end Rule (CendR) peptides (RPARPAR, PL3, iRGD) for CNV targeting and to evaluate the efficacy of peptides for treating experimental CNV in mice. We observed that the CendR peptides localize to the CNV lesion sites after intravitreal injection and were mainly found in the outer nuclear cell layer (ONL) of the mouse retina. Interestingly, experimental therapy with tenascin-C (TNC-C) and neuropilin-1 (NRP-1)-targeting PL3 peptide, reduced angiogenesis and decreased vascular leakage. The results suggest that PL3 and potentially other CendR peptides could serve as affinity targeting ligands and therapeutics for ocular diseases that involve pathological CNV.

Antiangiogenic AAV2 gene therapy with a truncated form of soluble VEGFR-2 reduces the growth of choroidal neovascularization in mice after intravitreal injection

Pathological angiogenesis related to neovascularization in the eye is mediated through vascular endothelial growth factors (VEGFs) and their receptors. Ocular neovascular-related diseases are mainly treated with anti-VEGF agents. In this study we evaluated the efficacy and safety of novel gene therapy using adeno associated virus 2 vector expressing a truncated form of soluble VEGF receptor-2 fused to the Fc-part of human IgG1 (AAV2-sVEGFR-2-Fc) to inhibit ocular neovascularization in laser induced choroidal neovascularization (CNV) in mice. The biological activity of sVEGFR-2-Fc was determined in vitro. It was shown that sVEGFR-2-Fc secreted from ARPE-19 cells was able to bind to VEGF-A₁₆₅ and reduce VEGF-A₁₆₅ induced cell growth and survival. A single intravitreal injection (IVT) of AAV2-sVEGFR-2-Fc (1 μl, 4.7 × 10¹² vg/ml) one-month prior laser photocoagulation did not cause any changes in the retinal morphology and significantly suppressed fluorescein leakage at 7, 14, 21 and 28 days post-lasering compared to controls. Macrophage infiltration was observed after the injection of both AAV2-sVEGFR-2-Fc and PBS. Our findings indicate that AAV2 mediated gene delivery of the sVEGFR-2-Fc efficiently reduces formation of CNV and could be developed to a therapeutic tool for the treatment of retinal diseases associated with neovascularization.

Pharmacokinetics of Pullulan-Dexamethasone Conjugates in Retinal Drug Delivery

The treatment of retinal diseases by intravitreal injections requires frequent administration unless drug delivery systems with long retention and controlled release are used. In this work, we focused on pullulan (≈67 kDa) conjugates of dexamethasone as therapeutic systems for intravitreal administration. The pullulan-dexamethasone conjugates self-assemble into negatively charged nanoparticles (average size 326 ± 29 nm). Intravitreal injections of pullulan and pullulan-dexamethasone were safe in mouse, rat and rabbit eyes. Fluorescently labeled pullulan particles showed prolonged retention in the vitreous and they were almost completely eliminated via aqueous humor outflow. Pullulan conjugates also distributed to the retina via Müller glial cells when tested in ex vivo retina explants and in vivo. Pharmacokinetic simulations showed that pullulan-dexamethasone conjugates may release free and active dexamethasone in the vitreous humor for over 16 days, even though a large fraction of dexamethasone may be eliminated from the eye as bound pullulan-dexamethasone. We conclude that pullulan based drug conjugates are promising intravitreal drug delivery systems as they may reduce injection frequency and deliver drugs into the retinal cells.

Ocular metabolism and distribution of drugs in the rabbit eye: Quantitative assessment after intracameral and intravitreal administrations

Quantitation of ocular drug metabolism is important, but only sparse data is currently available. Herein, the pharmacokinetics of four drugs, substrates of metabolizing enzymes, was investigated in albino rabbit eyes after intracameral and intravitreal administrations. Acetaminophen, brimonidine, cefuroxime axetil, and sunitinib and their corresponding metabolites were quantitated in the cornea, iris-ciliary body, aqueous humor, lens, vitreous humor, and neural retina with LC-MS/MS analytics. Non-compartmental analysis was employed to estimate the pharmacokinetic parameters of the parent drugs and metabolites. The area under the curve (AUC) values of metabolites were 12-70 times lower than the AUC values of the parent drugs in the tissues with the highest enzymatic activity. The ester prodrug cefuroxime axetil was an exception because it was efficiently and quantitatively converted to cefuroxime in the ocular tissues. In contrast to the liver, sulfotransferases, aldehyde oxidase, and cytochrome P450 3A activities were low in the eye and they had negligible impact on ocular drug clearance. With the exception of esterase substrates, metabolism seems to be a minor player in ocular pharmacokinetics. However, metabolites might contribute to ocular toxicity, and drug metabolism in various eye tissues should be investigated and understood thoroughly.

Retinal neuroprotection by controlled release of a VCP inhibitor from self-assembled nanoparticles

Mutations in rhodopsin lead to its misfolding resulting in autosomal dominant retinitis pigmentosa (adRP). Pharmacological inhibition of the ATP-driven chaperone valosin-containing protein (VCP), a molecular checkpoint for protein quality control, slows down retinal degeneration in animal models. However, poor water-solubility of VCP inhibitors poses a challenge to their clinical translation as intravitreal injections for retinal treatment. In order to enable the delivery of VCP inhibitors, we have developed and investigated two formulations for the VCP inhibitor ML240. Nanoformulations of ML240 were obtained by using amphiphilic polymers methoxy-poly (ethylene glycol)_5kDa-cholane (mPEG_5kDa-cholane) and methoxy-poly (ethylene glycol)_5kDa-cholesterol (mPEG_5kDa-cholesterol). Both formulations increased the water-solubility of ML240 by two orders of magnitude and prolonged the drug released over ten days. In addition, encapsulation of ML240 in mPEG_5kDa-cholane showed superior photoreceptor protection at lower drug concentrations, normalized rhodopsin localization, and alleviated inflammatory microglial responses in an ex vivo rat model of retinal degeneration. The study demonstrates the potential of VCP inhibitor nanoformulations to treat adRP, a pharmacologically orphan disease.

Magnetically Assisted Drug Delivery of Topical Eye Drops Maintains Retinal Function In Vivo in Mice

Barded-Biedl syndrome (BBS) is a rare genetic disorder with an unmet medical need for retinal degeneration. Small-molecule drugs were previously identified to slow down the apoptosis of photoreceptors in BBS mouse models. Clinical translation was not practical due to the necessity of repetitive invasive intravitreal injections for pediatric populations. Non-invasive methods of retinal drug targeting are a prerequisite for acceptable adaptation to the targeted pediatric patient population. Here, we present the development and functional testing of a non-invasive, topical, magnetically assisted delivery system, harnessing the ability of magnetic nanoparticles (MNPs) to cargo two drugs (guanabenz and valproic acid) with anti-unfolded protein response (UPR) properties towards the retina. Using magnetic resonance imaging (MRI), we showed the MNPs' presence in the retina of Bbs wild-type mice, and their photoreceptor localization was validated using transmission electron microscopy (TEM). Subsequent electroretinogram recordings (ERGs) demonstrated that we achieved beneficial biological effects with the magnetically assisted treatment translating the maintained light detection in Bbs^-/- mice (KO). To our knowledge, this is the first demonstration of efficient magnetic drug targeting in the photoreceptors in vivo after topical administration. This non-invasive, needle-free technology expands the application of SMDs for the treatment of a vast spectrum of retinal degenerations and other ocular diseases.

Ocular pharmacokinetics of atenolol, timolol and betaxolol cocktail: Tissue exposures in the rabbit eye

Quantitative understanding of pharmacokinetics of topically applied ocular drugs requires more research to further understanding and to eventually allow predictive in silico models to be developed. To this end, a topical cocktail of betaxolol, timolol and atenolol was instilled on albino rabbit eyes. Tear fluid, corneal epithelium, corneal stroma with endothelium, bulbar conjunctiva, anterior sclera, iris-ciliary body, lens and vitreous samples were collected and analysed using LC-MS/MS. Iris-ciliary body was also analysed after intracameral cocktail injection. Non-compartmental analysis was utilized to estimate the pharmacokinetics parameters. The most lipophilic drug, betaxolol, presented the highest exposure in all tissues except for tear fluid after topical administration, followed by timolol and atenolol. For all drugs, iris-ciliary body concentrations were higher than that of the aqueous humor. After topical instillation the most hydrophilic drug, atenolol, had 3.7 times higher AUC_{iris-ciliary body} than AUC_{aqueous humor}, whereas the difference was 1.4 and 1.6 times for timolol and betaxolol, respectively. This suggests that the non-corneal route (conjunctival-scleral) was dominating the absorption of atenolol, while the corneal route was more important for timolol and betaxolol. The presented data increase understanding of ocular pharmacokinetics of a cocktail of drugs and provide data that can be used for quantitative modeling and simulation.

Pharmacokinetics of intravitreal macromolecules: Scaling between rats and rabbits

Rats are widely used to study ocular drug responses, whereas rabbits are the most widely used preclinical model of ocular pharmacokinetics. Despite their wide use in evaluation of intravitreally injected drugs, translational information about pharmacokinetics and dose scaling between rats and rabbits is missing. In this study, we investigated intravitreal pharmacokinetics in rats and rabbits using non-invasive ocular fluorophotometry. Fluorescein and fluorescently labeled molecules (dextrans) with different molecular weights (376 Da, 10, 150 and 500 kDa), were injected into the vitreous of rabbits and rats. Intravitreal concentrations of the compounds were determined and pharmacokinetic parameters were calculated. Overall, the elimination half-lives of the macromolecules in rat vitreous were 5-6 times shorter than in rabbits, and the half-lives were prolonged at increasing molecular weights. The apparent volumes of distribution for tested compounds in rats and rabbits were in the range of the anatomical vitreal volumes. In both species, anterior route of elimination was predominant for the dextrans, whereas fluorescein was mainly eliminated via posterior route. Rabbit-to-rat ratios for intravitreal clearance were in the range of 2 to 5 for dextrans. Therefore, 2-5 times higher doses are needed for similar drug exposure in rabbits than in rats. Also, the shorter half-lives of macromolecules in the rat vitreous must be taken into account in translation to rabbit and human studies. The scaling factors presented herein will augment translational drug development for eye diseases.

Topical ocular pharmacokinetics and bioavailability for a cocktail of atenolol, timolol and betaxolol in rabbits

Ocular bioavailability after eye drops administration is an important, but rarely determined, pharmacokinetic parameter. In this study, we measured the pharmacokinetics of a cocktail of three beta blockers after their topical administration into the albino rabbit eye. Samples from aqueous humour were analysed with LC-MS/MS. The pharmacokinetic parameters were estimated using compartmental and non-compartmental analyses. The ocular bioavailability was covering broad range of values: atenolol (0.07 %), timolol (1.22%, 1.51%) and betaxolol (3.82%, 4.31%). Absolute ocular bioavailability presented a positive trend with lipophilicity and the values showed approximately 60-fold range. The generated data enhances our understanding for ocular pharmacokinetics of drugs and may be utilized in pharmacokinetic model building in ophthalmic drug development.

Retinal Degeneration In A Mouse Model Of CLN5 Disease Is Associated With Compromised Autophagy

The Finnish variant of late infantile neuronal ceroid lipofuscinosis (CLN5 disease) belongs to a family of neuronal ceroid lipofuscinosis (NCLs) diseases. Vision loss is among the first clinical signs in childhood forms of NCLs. Mutations in CLN5 underlie CLN5 disease. The aim of this study was to characterize how the lack of normal functionality of the CLN5 protein affects the mouse retina. Scotopic electroretinography (ERG) showed a diminished c-wave amplitude in the CLN5 deficient mice already at 1 month of age, indicative of pathological events in the retinal pigmented epithelium. A- and b-waves showed progressive impairment later from 2 and 3 months of age onwards, respectively. Structural and immunohistochemical (IHC) analyses showed preferential damage of photoreceptors, accumulation of autofluorescent storage material, apoptosis of photoreceptors, and strong inflammation in the CLN5 deficient mice retinas. Increased levels of autophagy-associated proteins Beclin-1 and P62, and increased LC3b-II/LC3b-I ratio, were detected by Western blotting from whole retinal extracts. Photopic ERG, visual evoked potentials, IHC and cell counting indicated relatively long surviving cone photoreceptors compared to rods. In conclusion, CLN5 deficient mice develop early vision loss that reflects the condition reported in clinical childhood forms of NCLs. The vision loss in CLN5 deficient mice is primarily caused by photoreceptor degeneration.

Combined Ct-Guided Biopsy and Cytology in Diagnosis of Bony Lesions

The results of 44 trephine (OD 1.4–4 mm) biopsies and 39 fine needle (0.7–0.9 mm) aspirations of skeletal, mainly vertebral, lesions performed under CT-guidance in 54 patients were evaluated. The fine needle sample was aspirated through the trephine as a complementary procedure in 29 patients and a fine needle aspiration only was performed in 10 patients. Trephine biopsy only was performed in 15 patients. Sufficient material for histologic and cytologic analyses was obtained in 93% (41/44) and 97% (38/39) and a correct benign or malignant diagnosis was obtained in 84% (37/44) and 90% (35/39), respectively. Among the combined examinations the fine needle aspiration alone was diagnostic in 2 cases while the trephine specimen alone provided diagnostic material in 2 cases. In 24 cases both the cytologic and histologic samples were adequate for diagnostic purposes. In one case both methods gave false-negative results. The combined use of cytologic and histologic samples in CT-guided bone biopsies increased diagnostic accuracy. The aorta was perforated once with a 1.4-mm needle but without sequelae. CT-guided bone biopsy was found to be a safe, reliable and cost-efficient method.

Early retinal function deficit without prominent morphological changes in the R6/2 mouse model of Huntington's disease

Huntington’s disease (HD) is an inherited neurodegenerative disorder that primarily affects the medium-size GABAergic neurons of striatum. The R6/2 mouse line is one of the most widely used animal models of HD. Previously the hallmarks of HD-related pathology have been detected in photoreceptors and interneurons of R6/2 mouse retina. Here we aimed to explore the survival of retinal ganglion cells (RGCs) and functional integrity of distinct retinal cell populations in R6/2 mice. The pattern electroretinography (PERG) signal was lost at the age of 8 weeks in R6/2 mice in contrast to the situation in wild-type (WT) littermates. This defect may be attributable to a major reduction in photopic ERG responses in R6/2 mice which was more evident in b- than a-wave amplitudes. At the age of 4 weeks R6/2 mice had predominantly the soluble form of mutant huntingtin protein (mHtt) in the RGC layer cells, whereas the aggregated form of mHtt was found in the majority of those cells from the 12-week-old R6/2 mice and onwards. Retinal astrocytes did not contain mHtt deposits. The total numbers of RGC layer cells, retinal astrocytes as well as optic nerve axons did not differ between 18-week-old R6/2 mice and their WT controls. Our data indicate that mHtt deposition does not cause RGC degeneration or retinal astrocyte loss in R6/2 mice even at a late stage of HD-related pathology. However, due to functional deficits in the rod- and cone-pathways, the R6/2 mice suffer progressive deficits in visual capabilities starting as early as 4 weeks; at 8 weeks there is severe impairment. This should be taken into account in any behavioral testing conducted in R6/2 mice.

Neuroradiological findings (MRS, MRI, SPECT) in infantile neuronal ceroid-lipofuscinosis (infantile CLN1) at different stages of the disease

Infantile neuronal ceroid-lipofuscinosis (infantile CLN1) is a progressive and uniformly fatal lysosomal storage disease of the nervous system. The purpose of this study was to compare the findings of various radiological examinations of the brain in the course of infantile CLN1 in order to evaluate the relative usefulness of the methods and their potential for monitoring therapeutic interventions. We examined eight infantile CLN1 patients, 51 studies, in various stages of the disease--preclinical to late stage--with proton magnetic resonance spectroscopy (1H-MRS), MRI, and perfusion SPECT, and in addition three benzodiazepine (BZ) receptor ligand SPECT studies. Both 1H-MRS and MRI showed abnormal findings before clinical manifestations of the disease. Cortical hypoperfusion and loss of cortical BZ receptors revealed by SPECT appeared simultaneously with clinical signs. After the age of 4 years MRI and SPECT alterations progressed minimally, whereas 1H-MRS showed progressive deterioration of neurometabolism. Of the four methods used in this study, MRI proved to be the most practicable for diagnosing infantile CLN1; the final diagnosis of infantile CLN1 is confirmed by the characteristic clinical picture and DNA or PPT enzyme analysis. The combination of 1H- MRS and MRI could be most useful for monitoring therapeutic interventions.

Acute bilateral exercise-induced medial compartment syndrome of the thigh. Correlation of repeated MRI with clinicopathological findings

We present a case report of acute bilateral excercise-induced compartment syndrome in the adductor longus muscles, which was treated with bilateral medial fasciotomies. Postoperatively, the healing process of the adductor muscles was followed up by repeated MR imagings over six months. Myonecrosis was found in peroperative muscle biopsies. Pain and muscle swelling subsided soon after the fasciotomy, correlating with the early postoperative MR findings. Four months postoperatively, the signal intensity of the adductor muscles was normal in T1- and T2-weighted images, but the normal fibre structure of the adductor muscles could only be seen 6 months postoperatively. At six month's control checkup there was no subjective weakness of the adductors, and hyperesthesia had disappeared and the patient was capable of normal activities.

Extensive cerebral white matter abnormality without clinical symptoms: a new hereditary condition?

A 30-year-old father and his 2 sons with slight hyperkinesia and mildly dysmorphic features and their close relatives were examined clinically and with computed tomography (CT) and magnetic resonance imaging (MRI). Neurophysiological and biochemical examinations were normal; however, brain MRI of the father and sons revealed extensive cerebral white matter changes. No radiological progression could be detected at a 13-year follow-up examination of the father, and proton magnetic resonance spectroscopy (MRS) of the father at the age of 30 years was normal. MRI findings in the relatives were normal, suggesting an autosomal dominant syndrome due to a new mutation in the father.

Delayed classic and protracted phenotypes of compound heterozygous juvenile neuronal ceroid lipofuscinosis

OBJECTIVE

To correlate the phenotypes with the genotypes of 10 Finnish juvenile neuronal ceroid lipofuscinosis (JNCL; late-onset Batten disease) patients who all are compound heterozygotes for the major 1.02-kb deletion in the CLN3 gene.

METHODS

The mutations on the non-1.02-kb deletion chromosomes were screened in 6 patients; in the other 4 patients the mutations were known (one affecting a splice site, two missense mutations, and one deletion of exons 10 through 13). Clinical features were examined, and MRI, MRS, somatosensory evoked magnetic field (SEF), and overnight polysomnography (PSG) studies were performed.

RESULTS

A novel deletion of exons 10 through 13 was found in 6 patients belonging to three families. In the patients carrying the deletions of exons 10 through 13 the clinical course of the disease was fairly similar. Variation was greatest in the time course to blindness. In these patients the mental and motor decline was slower than in classic JNCL, but more severe than in the two patients with missense mutations in exons 11 and 13. MRI showed brain atrophy in 4 patients. One patient had hyperintense periventricular white matter, otherwise brain signal intensities were normal. SEFs were enhanced in patients older than 14 years, whereas in PSG all but the youngest 6-year-old patient showed epileptiform activity in slow-wave sleep.

CONCLUSIONS

JNCL can manifest as at least three different phenotypes: classic, delayed classic, and protracted JNCL with predominantly ocular symptoms. Finnish compound heterozygotes have the delayed classic or the protracted form of JNCL.

Efficacy of antiplatelet treatment in hypertensive patients with TIA or stroke

We performed a subgroup analysis of the first European Stroke Prevention Study including 1,306 patients recruited in a single center, Kuopio, Finland, to investigate whether or not antiplatelet therapy is effective in the secondary prevention of stroke in hypertensive patients with transient ischemic attack (TIA) or stroke. The patients were treated with aspirin, 990 mg/day, plus dipyridamole, 225 mg/day, or placebo for 2 years. The patients with high systolic blood pressure (> or = 140 mm Hg; n = 1.105) or high diastolic blood pressure (> or = 85 mm Hg; n = 1,120) at entry, were classified into subgroups by blood pressure level. The effect of treatment was statistically significant in all subgroups with high systolic (end-point reduction, 55.2-68.2%) and diastolic blood pressure (end-point reduction, 47.3-82.1%). Risk reduction was, however, greatest in patients with the highest diastolic blood pressure. One possible explanation is that platelets are more activated in these patients, and this can be effectively prevented by antiplatelet therapy. Further studies are needed to confirm this hypothesis.

Risk factors and antiplatelet therapy in TIA and stroke patients

Antiplatelet treatment is well established in the secondary prevention of ischemic cerebrovascular events. The reasons for the occurrence of stroke, even though the patient receives drug treatment, have remained unclear. We performed a subgroup analysis of the European Stroke Prevention Study (ESPS 1) to investigate the efficacy of treatment in patients with different cardiovascular risk factors. The ESPS 1 recruited 1306 patients with TIA, RIND or stroke in one single center of Kuopio in Finland. The patients were treated with aspirin 990 mg/day+dipyridamole 225 mg/day or placebo for 2 years or until an endpoint. The endpoints were stroke or death from any cause. The risk factors for endpoints were analyzed by Cox univariate regression analyses. The effect of a single risk factor on the efficacy of antiplatelet therapy was analyzed by Cox proportional hazards model in subgroups according to the significant risk factors found in the univariate analysis. The efficacy of treatment was statistically significant in all subgroups except diabetics and current smokers for the stroke endpoint. When the combined endpoint of stroke or death was used, the treatment failed also to show statistical significance in patients with coronary heart disease. This lack of efficacy might be due to the small sample size. The efficacy of treatment was significantly better in TIA patients than in stroke patients when analyzed with stroke as an end point. This study provides strong evidence that the effectiveness of antiplatelet treatment in ischemic stroke and TIA patients is independent of most cardiovascular risk factors. Furthermore, all patients with TIA and ischemic stroke should receive secondary prevention regardless of whether or not there are risk factors.

Outcome and prognostic factors of achilles rupture repair using a new scoring method

A new clinical scoring system, including subjective assessment of symptoms and evaluation of ankle range of motion and isokinetic measurement of ankle plantar flexion and dorsiflexion strengths, is presented in 101 patients (86 men, 15 women) who had repair of a closed Achilles tendon rupture. Twenty-one patients were competitive athletes and 70 were recreational athletes. Eighty-one percent of the ruptures were related to sports, and 32% occurred while playing volleyball. Twenty-six patients had previous Achilles tendon symptoms. At followup, an average of 3.1 years after repair, the overall result scores were excellent in 34 cases, good in 46, fair in 17, and poor in four. Only age was a predictor of overall results. The isokinetic strength scores were excellent or good in 72 cases, fair in 18, and poor in 11. Presence of systemic diseases, activity level, previous Achilles tendon symptoms, and later return to physical exercise were predictors of strength results. Gender, body weight, height, period between rupture and operation, surgeon, rupture site, operative method, complications, and thickness, width, and area of the Achilles tendon at followup were not related significantly to the outcome.

Incidence of Achilles tendon rupture

We determined the incidence of a total Achilles tendon rupture in the city of Oulu and changes over the 16-year period 1979-1994. During this time, 110 ruptures occurred. The incidence increased from 2 ruptures/10(5) inhabitants in 1979-1986 to 12 in 1987-1994, with a mean of 7. The peak annual incidence, 18, was recorded in 1994. The incidence was highest in the age group 30-39 years. Male dominance was 5.5:1, and 81% of the ruptures were related to sports, with 88% occurring in ball games. The mean age was significantly lower for the sports injuries.

ABO blood group and Achilles tendon rupture

The association between ABO blood groups and Achilles tendon (AT) ruptures was studied in 215 consecutive AT rupture patients treated at Oulu University Hospital during the 16-year period from 1979 to 1994 as compared with control material consisting of earlier blood group determinations performed on an unselected sample of 5,536 young Finnish male adults. There was no blood group O dominance or other statistical differences in ABO blood groups between the patients with AT rupture and the control population (chi 2 3.79, P = 0.28), the A/O ratio being 1.82 in the rupture group and 1.42 in the controls. We found no blood group O dominance in competitive athletes, recreational athletes or non-athletes, in patients with sports-related AT ruptures or non-sports-related ruptures and in younger (< 45 years) or older (> or = 45--years) patients. In conclusion, our results do not confirm early findings of blood group O dominance in patients with AT rupture.

Responses of type I and type III collagen synthesis after replacement of the hip joint

Liberation of the carboxy-terminal propeptide of type I procollagen (PICP) and the amino-terminal propeptide of type III procollagen (PIIINP) into body fluids reflects synthesis of the respective collagen types. Here, we followed PICP and PIIINP in serum with specific radioimmunoassays after hip surgery. Preoperative median of S-PICP was 112 micrograms/liter (range 87 to 154, n = 9), the 1-day median being 58 micrograms/liter (33 to 79). The corresponding medians for S-PIIINP were 4.4 micrograms/liter (3.5 to 7.0) and 3.3 micrograms/liter (2.0 to 3.5). The medians reached their maximums 14 days after surgery, 172 micrograms/liter (122 to 440) for S-PICP and 12.4 micrograms/liter (8.0 to 15.4) for S-PIIINP, after which the preoperative values were slowly approached over several months. Comparable results were found in a greater sample (n = 50). Our results indicate that the synthesis of structural collagen is inhibited immediately after surgery, but the inhibition is soon overcome by active collagen synthesis at the site of trauma. Collagen metabolism remains activated for several months after surgery.

Total hip arthroplasty using isoelastic femoral stems. A seven- to nine-year follow-up in 108 patients

From 1983 to 1985 we performed 114 primary hip replacements in 108 consecutive osteoarthritic patients using a non-cemented RM isoelastic femoral stem. After a mean follow-up of 8.2 years, ten patients had died, 11 hips had been revised, six patients had been lost to follow-up and two had been excluded due to severe general illnesses. Of 85 arthroplasties (in 79 patients) 14 could not be assessed because of other illness or disability. The 71 remaining were reviewed by questionnaire and radiography; an excellent or good overall functional result was found in 31, 16 were fair and 24 were poor. Radiographically, 21 of 71 stems were judged to be loose and ten showed osteolytic foci, six of these without obvious loosening. We conclude that the isoelastic RM stem shows a high rate of loosening, but that this is not always associated with a poor subjective result. Regular radiographic review is necessary. The results are worse than those reported for other uncemented stems and for cemented stems.

Total hip arthroplasty using isoelastic femoral stems. A seven- to nine-year follow-up in 108 patients

From 1983 to 1985 we performed 114 primary hip replacements in 108 consecutive osteoarthritic patients using a non-cemented RM isoelastic femoral stem. After a mean follow-up of 8.2 years, ten patients had died, 11 hips had been revised, six patients had been lost to follow-up and two had been excluded due to severe general illnesses. Of 85 arthroplasties (in 79 patients) 14 could not be assessed because of other illness or disability. The 71 remaining were reviewed by questionnaire and radiography; an excellent or good overall functional result was found in 31, 16 were fair and 24 were poor. Radiographically, 21 of 71 stems were judged to be loose and ten showed osteolytic foci, six of these without obvious loosening. We conclude that the isoelastic RM stem shows a high rate of loosening, but that this is not always associated with a poor subjective result. Regular radiographic review is necessary. The results are worse than those reported for other uncemented stems and for cemented stems.

Operative treatment of partial rupture of the patellar ligament. A study of 138 cases

One hundred and thirty eight knees of 124 patients with partial rupture of the patellar ligament were treated surgically after failure to heal them by conservative means. Ultrasonography was used to confirm the diagnosis in 45 knees, and when positive it had a good correlation with the operative findings. During surgery excision of the devitalized tissue in the patellar tendon was performed. Histologic examination of the removed tissue revealed degenerated, fibrotic tissue with neo-vascularization, and slight to moderate inflammation resembling devitalized tissue. The patients were re-examined 18.6 +/- 15.0 months post-operatively. Ninety-seven patients (111 knees = 80.4%) benefitted from the operation with excellent or good results. Thirteen knees had to be re-operated with more radical excision due to renewed symptoms. In conclusion, surgical excision of the devitalized tissues gives a good functional result in most of the cases in which non-operative treatment with rest and physical treatment has failed, helping the athlete to return to his pre-injury activities.

Arthrography for the diagnosis of acute lateral ligament injuries of the ankle

Arthrography was used for diagnosis of ruptures of lateral ligaments in 589 acutely injured ankles that were treated operatively. The accuracy of the method was tested comparing the findings of arthrography with those at operation. We found arthrography to be almost 100% reliable for diagnosing a fresh anterior talofibular ligament rupture. The best criterion for detecting calcaneofibular ligament rupture was filling of the peroneal tendon sheath with contrast medium. Leakage below and behind the lateral malleolus, when present with peroneal tendon sheath filling, confirms the diagnosis of calcaneofibular ligament rupture, but these findings without peroneal tendon sheath filling are too rare to base the diagnosis on them alone.

Effect of a non-steroidal anti-inflammatory drug, diclofenac, on haemostasis in patients undergoing total hip replacement

Haemostasis was studied in patients receiving diclofenac for postoperative pain relief. Intravenous diclofenac 75 mg over 60 min, followed first by an infusion of 5 mg/h for 15 h and then by 50 mg every 8 h orally was administered to 20 patients undergoing total hip replacement. Eighteen patients receiving a placebo infusion and dextropropoxyfen per os served as controls. The results showed no statistically significant differences between the groups in blood loss, bleeding time (IVY), partial activated thromboplastin time and prothrombin complex assay or in platelet count. The measurements were performed preoperatively, 3 h postoperatively and on the fourth and tenth postoperative days. Plasma concentrations were also determined in ten patients undergoing knee arthroscopy. An i.v. diclofenac infusion of 75 mg over a period of 15 min was administered either once (to half of the patients) or twice. The mean diclofenac concentrations were 28 +/- 5 nmol/ml (+/- s.d.) after 15 min and 36 +/- 12 nmol/ml after the second infusion. The bleeding time in the arthroscopy patients receiving one or two bolus infusions of 75 mg diclofenac remained at the control level. It is concluded that diclofenac given as an intravenous infusion of 75 mg in 60 min, then 5 mg/h for 15 h, followed by 50 mg every 8 h orally, is a safe as dextropropoxyfen for pain relief in patients undergoing major orthopaedic surgery as far as coagulation data are concerned.

Combined CT-guided biopsy and cytology in diagnosis of bony lesions

The results of 44 trephine (OD 1.4-4 mm) biopsies and 39 fine needle (0.7-0.9 mm) aspirations of skeletal, mainly vertebral, lesions performed under CT-guidance in 54 patients were evaluated. The fine needle sample was aspirated through the trephine as a complementary procedure in 29 patients and a fine needle aspiration only was performed in 10 patients. Trephine biopsy only was performed in 15 patients. Sufficient material for histologic and cytologic analyses was obtained in 93% (41/44) and 97% (38/39) and a correct benign or malignant diagnosis was obtained in 84% (37/44) and 90% (35/39), respectively. Among the combined examinations the fine needle aspiration alone was diagnostic in 2 cases while the trephine specimen alone provided diagnostic material in 2 cases. In 24 cases both the cytologic and histologic samples were adequate for diagnostic purposes. In one case both methods gave false-negative results. The combined use of cytologic and histologic samples in CT-guided bone biopsies increased diagnostic accuracy. The aorta was perforated once with a 1.4-mm needle but without sequelae. CT-guided bone biopsy was found to be a safe, reliable and cost-efficient method.

Arthrography, clinical examination, and stress radiograph in the diagnosis of acute injury to the lateral ligaments of the ankle

We examined 188 consecutive patients, each of whom had an acute ankle sprain, using clinical stability assessment, stress radiographs, and arthrography to compare the reliability of these methods used in diagnosing lateral ligament ruptures of the ankle. Sixty-six of the ankles were treated operatively. Arthrography accurately detected ligament damage in all of the patients with this injury and revealed the extent of the injury in about 85%, whereas clinical examination and stress radiographs detected only about half of the injuries. The injuries and the results of these two methods were often controversial, as our study will show.

Effect of immobilization on carbonic anhydrase III and myoglobin content in human leg muscle

Carbonic anhydrase III and myoglobin concentrations were measured from vastus medialis muscle samples before and 6 weeks after postoperative leg immobilization following knee ligament reconstruction. Seven patients were immobilized with conventional cast so that the knee joint was fixed at 20 degrees flexion. Seven other patients used braces allowing a motion of 30-70 degrees. The atrophy of the medial part of musculus quadriceps was estimated by computer tomography. No difference in carbonic anhydrase III and myoglobin concentrations or muscle atrophy between the cast and brace groups was observed. The cross-sectional area of the medial part of musculus quadriceps decreased 38% during immobilization. The specific concentrations of carbonic anhydrase III and myoglobin remained unaltered. Due to the remarkable postoperative atrophy of the muscle the total carbonic anhydrase III and myoglobin contents, however, decreased significantly (37% and 31%, respectively). The results suggest that the net breakdown of carbonic anhydrase III and myoglobin during disuse atrophy occur at the same rate as the average net degradation of mixed muscle proteins and that the process is independent of the immobilization procedure.

Arthrodesis of the knee with intramedullary nail fixation

Thirty-three patients had an arthrodesis of the knee by means of an intramedullary nail introduced through the greater trochanter. Fifteen of the procedures were done for a failed knee arthroplasty; eight had failed because of infection and seven, because of aseptic loosening. Twenty-nine of the thirty-three knees united three to four months after the first attempt at arthrodesis and three united after technical errors were corrected. One knee had a broken nail and a non-union; this was still untreated at the time of writing. Four nails broke: three in the line of fusion and one in the line of an infected supracondylar pseudarthrosis of the femur. No new infections developed after the arthrodesis. Three patients had had an infection and a chronic fistula before the arthrodesis, and the fistulae healed six, fourteen, and eighteen months postoperatively. In another patient, who had had infection and necrosis of the skin preoperatively, the wound healed in six months. All of these knees healed without an additional major operation. The functional result was satisfactory in all patients. After the arthrodesis, seventeen of the thirty-three patients needed less aid when walking, and no patient needed more aid. Fusion of the knee with a long intramedullary nail can be safe and effective, even in the presence of infection, if the revision is performed properly and certain technical principles are followed. It is especially important to establish good contact between the resected bones.

Air bacterial and particle counts in total hip replacement operations using non-woven and cotton gowns and drapes

Air bacterial and particle counts were obtained in a conventionally ventilated operating theatre, during 8 operations for total hip replacement performed using synthetic non-woven fabrics as drapes for the patients and gowns for the staff (trousers and stockings were of conventional cotton material), ('non-woven' group), and in 8 corresponding operations using conventional cotton fabrics ('cotton' group). No significant difference between the groups with regard to air bacterial counts was observed. The use of cotton fabrics was associated with substantially higher particle counts, probably due to particles from the cotton textiles themselves. No significant correlation was observed between the bacterial and particle counts, indicating that these came from different sources and that the particles were mainly of sterile origin. Thus, the benefit of the synthetic, non-woven fabrics in hip replacement surgery, when these fabrics are used to cover theatre staff only partially in the form of gowns, seems questionable with regard to the reduction of air bacterial counts. On the other hand, the surgical textiles of non-woven material improve the purity of the operating theatre since unlike cotton fabrics they do not produce and disperse particles in the air.

Serum carbonic anhydrase III, an enzyme of type I muscle fibres, and the intensity of physical exercise

The effects of 30 min running with stepwise increasing intensity (exhaustive, energy demand approx. 50----100% of VO2max), 60 s supramaximal running (anaerobic, greater than or equal to 125% of VO2max) and 40-60 min low-intensity running (aerobic, 40-60% of VO2max) on serum concentration of muscle-derived proteins were studied in 5 male and 5 female elite orienteerers. S-Carbonic anhydrase III (S-CA III) was used as a marker of protein leakage from type I (slow oxidative) muscle fibres and S-myoglobin (S-Mb) as a non-selective (type I + II) muscular marker. The fractional increase in S-CA III (delta S-Ca III) was 0.37 +/- 0.09 (mean +/- SEM, p less than 0.001), 0.10 +/- 0.05 (N. S.) and 0.46 +/- 0.09 (p less than 0.001) 1 h after exhaustive, anaerobic and aerobic exercise, respectively. The corresponding values for delta S-Mb were 1.45 +/- 0.36 (p less than 0.001), 0.39 +/- 0.13 (p less than 0.01) and 0.67 +/- 0.18 (p less than 0.001). The value for the delta S-CA III/delta S-Mb ratio was 0.68 +/- 0.03 after the aerobic exercise, but only 0.25-0.26 (p vs. aerobic exercise less than 0.001) after the two high-intensity forms of exercise. Since type I fibres of skeletal muscle are known to be responsible for power production during low-intensity exercise, whereas fibres of both type I and type II are active at higher intensities, the delta S-CA III/delta S-Mb ratio may depend on the recruitment profile of type I vs. type I + II fibres.

Examination of the sprained ankle: anterior drawer test or arthrography?

The accuracy of the anterior drawer test for the diagnosis of recent lateral ligament tears in the ankle was evaluated in a series of 192 patients using surgical or arthrographic findings for reference. Considerable overlapping of results was obtained in ankles with and without ligament tear. Twenty-eight per cent of the anterior talofibular ligament tears, and 38% of the combined anterior talofibular and calcaneofibular tears were not detected, and single and combined tears could not be differentiated. It is concluded that the anterior drawer test is too unreliable as a basis for any decision regarding surgical treatment of a recent sprain. Therefore, arthrography is recommended as the method of choice in such cases of recent ankle sprain, where the need of surgery has to be supported by X-ray analysis.

Collagen synthesis and proteolytic activities in rat skeletal muscles: effect of cast-immobilization in the lengthened and shortened positions

The activities of prolyl 4-hydroxylase (PH) and galactosylhydroxylysyl glucosyltransferase (GGT), both enzymes of collagen biosynthesis, were measured in the gastrocnemius, soleus, and tibialis anterior muscles of rats after bilateral cast-immobilization of the muscles in lengthened and shortened positions for one and three weeks. The activities of muscular proteolytic and hydrolytic enzymes cathepsin D (CD), beta-glucuronidase (beta-GU), alkaline protease (AP), and the rate of acid autolysis (AA) were also studied. The biochemical results were compared to the morphologic changes by light microscopy. Compared to the results for a control group, there was a decrease of 37% and 53% in the specific PH activity of shortened gastrocnemius and soleus, respectively, after three weeks of immobilization. The corresponding decrease in GGT of the shortened gastrocnemius was 47%. At the same time, PH and GGT in the lengthened plantarflexors were at the control level. The proteolytic activities of the shortened plantarflexors were generally higher (CD by approximately 30%, beta-GU of gastrocnemius by 81%, AP of soleus by 63%, AA of gastrocnemius by 34%, and AA of soleus by 56%) than those of the lengthened ones. Light microscopy of the shortened muscles showed numerous atrophic fibers, but no pronounced inflammatory response in the disused muscle tissue. The results suggest that increased proteolysis and wasting of muscle tissue during cast-immobilization is associated with adaptive responses in the metabolism of the muscular collagen network.

The hamstring syndrome. A new diagnosis of gluteal sciatic pain

A series of 59 patients was treated and operated on for pain felt over the area of the ischial tuberosity and radiating down the back of the thigh. This condition was labeled as the "hamstring syndrome." Pain was typically incurred by assuming a sitting position, stretching the affected posterior thigh, and running fast. The patients usually had a history of recurrent hamstring "tears." Their symptoms were caused by the tight, tendinous structures of the lateral insertion area of the hamstring muscles to the ischial tuberosity. Upon division of these structures, complete relief was obtained in 52 of the 59 patients.

The value of axial view in the radiography of shoulder girdle--experiences with a new modification of positioning

A series of 117 patients underwent radiography of the shoulder girdle, performed using a modification which allowed the examination of also severely injured patients in the axial view. The findings in the frontal and axial views were compared. A total number of 161 pathological findings were discovered; out of them 30 were visible only in the frontal view and 49 only in the axial view. The series indicates that the axial view can be taken painless in patients with recent injury, and that the frontal and axial views considerably supplement each other.