Insights into the present and future of cartilage regeneration and joint repair.

Knee osteoarthritis is the most common joint disease. It causes pain and suffering for affected patients and is the source of major economic costs for healthcare systems. Despite ongoing research, there is a lack of knowledge regarding disease mechanisms, biomarkers, and possible cures. Current treatments do not fulfill patients' long-term needs, and it often requires invasive surgical procedures with subsequent long periods of rehabilitation. Researchers and companies worldwide are working to find a suitable cell source to engineer or regenerate a functional and healthy articular cartilage tissue to implant in the damaged area. Potential cell sources to accomplish this goal include embryonic stem cells, mesenchymal stem cells, or induced pluripotent stem cells. The differentiation of stem cells into different tissue types is complex, and a suitable concentration range of specific growth factors is vital. The cellular microenvironment during early embryonic development provides crucial information regarding concentrations of signaling molecules and morphogen gradients as these are essential inducers for tissue development. Thus, morphogen gradients implemented in developmental protocols aimed to engineer functional cartilage tissue can potentially generate cells comparable to those within native cartilage. In this review, we have summarized the problems with current treatments, potential cell sources for cell therapy, reviewed the progress of new treatments within the regenerative cartilage field, and highlighted the importance of cell quality, characterization assays, and chemically defined protocols.

GDF5 induces TBX3 in a concentration dependent manner - on a gold nanoparticle gradient.

Organs and tissues, such as cartilage and limbs, are formed during development through an orchestration of growth factors that function as morphogens. Examples of growth factors include growth differentiation factor 5 (GDF5) and transforming growth factors beta 1 and 3 (TGFß-1 and TGFß-3) which can specify creation of more than one cell type after forming a concentration gradient in vivo. Here, we studied the impact of morphogen gradients during differentiation of induced pluripotent stem cells (iPSCs) into the chondrocyte lineage. Cell budding zones, consisting of condensed cell aggregates, were observed only in gradients of GDF5. T-box transcription factor 3 (TBX3) was detected specifically in the budding zones (ranging from 500-1,500 particles/µm2) of nuclei and cell vesicles. A homogenous density of GDF5 of 900 particles/µm2 on a surface induced budding and expression of TBX3 after five days in iPSCs. Therefore, we conclude that a gradient of GDF5, as well as the specific homogenous density of GDF5, support the induction of TBX3 in iPCSs. Moreover, differentiation of iPSCs first on GDF5 gradient or homogenous surfaces for five days and then in a three-dimensional structure for five weeks resulted in pellets that expressed TBX3.

A population-based study on brain atrophy and motor performance in elderly women.

BACKGROUND: Brain atrophy is a common neuroimaging finding in healthy elderly individuals as well as in patients with movement-related disorders. The relationship between brain atrophy and motor changes has not been frequently reported. This study investigates this relationship. METHODS: A population-based sample of women (N = 238), aged 70, 74, and 78 years, living in Göteborg, Sweden, participated in this study. Motor performance was measured by a laboratory test, the Postural-Locomotion-Manual test, which precisely measures the subject's mobility of lower and upper extremities using an optoelectronic technique. Cortical and central atrophy were rated on computerized tomographic (CT) scans of the brain. RESULTS: In bivariate analysis, temporal lobe atrophy, high sylvian fissure ratio, and high bicaudate ratio were correlated with impaired mobility. The association between temporal lobe atrophy and high sylvian fissure ratio and poor mobility remained after controlling for age, smoking, coronary heart disease, diabetes mellitus, hypertension, and white matter lesions on CT scans. CONCLUSIONS: Our results suggest that temporal lobe atrophy, which is often seen on brain imaging in elderly persons, might be an important brain abnormality related to motor impairments in elderly women. Further studies to investigate this relationship and its underlying mechanisms are needed.

Oral implant rehabilitation in irradiated patients without adjunctive hyperbaric oxygen.

In 15 patients treated for malignant tumors in the maxillofacial region, 90 Brånemark implants have been placed in irradiated alveolar bone without adjunctive hyperbaric oxygen therapy. Seventy-eight implants were placed in the mandible and 12 in the maxilla. After a follow-up period of 1 to 8 years, 88 implants are still stable, 27 after 6 to 8 years, 44 after 3 to 4 years, and 17 after 1 to 2 years. Two patients lost 1 implant each, both at an early stage. The success rate is 97.8% according to remaining implants, and prosthesis stability is 100%. Implant treatment for oral rehabilitation can be carried out as a safe and successful procedure in the irradiated patient without adjunctive hyperbaric oxygen therapy.

A population-based study on blood pressure and brain atrophy in 85-year-olds.

In the general population, mean systolic and diastolic blood pressure increases up to age 75 years but decreases thereafter. The brain has a role in blood pressure regulation; it is not clear whether the cerebral changes that occur with aging contribute to the decline in blood pressure in the very elderly. We examined a population-based sample of 484 85-year-old persons (344 nondemented and 140 demented, 61 with Alzheimer's disease, 65 with vascular dementia, and 14 with other types of dementia) with a neuropsychiatric examination and blood pressure measurements. Dementia was diagnosed according to the criteria proposed in the Diagnostic and Statistical Manual of Mental Disorders, edition 3, revised. Brain atrophy was measured by CT of the brain. In the nondemented group, frontal (r=-0.18, P=0.037) and parietal (r=-0.23, P=0.008) cortical atrophy and bifrontal ratio (r=-0.20, P=0.013) were associated with lower systolic blood pressure, and frontal (r=-0.23, P=0.010) and parietal (r=-0.24, P=0.008) cortical atrophy and bifrontal ratio (r=-0.23, P=0.006) with lower diastolic blood pressure. Systolic blood pressure was lower in subjects with Alzheimer's disease and vascular dementia, and diastolic blood pressure was lower in those with vascular dementia compared with the nondemented. Systolic (r=-0.27, P<0.0001) and diastolic (r=-0.10, P=0.020) blood pressure was negatively correlated to dementia severity. In the demented subjects, frontal cortical atrophy was correlated to lower diastolic blood pressure (r=-0.21, P=0.043). Our findings suggest that age-related changes in brain structure may contribute to the decrease in blood pressure in the very elderly and that low blood pressure in dementia disorders is mainly a secondary phenomenon.

Salivary gland anlage tumor: cytologic features in a case examined by fine-needle aspiration.

The cytologic features in fine-needle aspirates from a rare benign nasopharyngeal salivary gland anlage tumor in a newborn boy are described and commented on, regarding therapeutically important differential diagnoses.

Different manganese binding sites in photosystem II probed by selective chemical modification of histidyl and carboxylic acid residues.

The binding of Mn2+ to manganese-depleted photosystem II was investigated after chemical modification of histidyl and carboxylic acid residues in the presence or absence of the native manganese cluster. K(M) values for Mn2+ were determined from steady-state electron transfer between Mn2+ and 2,6-dichlorophenolindophenol, the dissociation constant for Mn2+ was measured by observing the effect of added Mn2+ on the reduction of the primary donor P680+ after a saturating flash, and single-turnover electron donation from Mn2+ was followed by monitoring the decay kinetics of the EPR signal from the flash-induced tyrosine Zox radical. K(M) values for Mn2+ were found to be highly pH-dependent in both modified and unmodified photosystem II membranes. Treatment with histidine modifiers after removal of the manganese complex increased the K(M) values between 2.5 and 10 times and increased the dissociation constant for Mn2+ 8-fold, compared to membranes that were modified in the presence of the manganese cluster. Modification of carboxylic acid residues after removal of the manganese cluster increased the K(M) about 5-fold compared to membranes that were modified in the presence of the manganese cluster. The reduction rate of tyrosine Zox by Mn2+ was diminished after modification of either histidine or carboxylic acid residues. The apparent second-order rate constant decreased from 2.6 x 10(6) M(-1) s(-1) to 0.05 x 10(6) M(-1) s(-1) after histidine modification in the presence or absence of manganese, to 0.77 x 10(6) M(-1) s(-1) after carboxylic acid residue modification in the presence of manganese, and to 0.18 x 10(6) M(-1) s(-1) after carboxylic acid modification in the absence of manganese. Our results indicate the existence of two different manganese binding sites containing histidine, and at least two manganese sites with carboxylic acid residues, which are differently shielded against modifying agents by the native manganese cluster.

Apolipoprotein E in cerebrospinal fluid in 85-year-old subjects. Relation to dementia, apolipoprotein E polymorphism, cerebral atrophy, and white matter lesions.

OBJECTIVE: To further elucidate the pathogenetic role of apolipoprotein E (Apo E) in degenerative brain disorders, we analyzed cerebrospinal fluid (CSF) levels of Apo E in 85-year-old subjects with dementia disorders. DESIGN: Survey. SETTING: Community. PARTICIPANTS: Population-based sample of 27 demented (12 with Alzheimer disease [AD]; 13, vascular dementia [VAD]; and 2, other types of dementia) and 35 nondemented individuals. MAIN OUTCOME MEASURES: Cerebrospinal fluid levels of Apo E, Apo E polymorphism, and brain atrophy and white matter lesions (WMLs) measured by computed tomography (CT) of the brain. Dementia was defined according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria; AD, National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association criteria; and VAD, National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neuroscience criteria. RESULTS: The mean (+/- SD) CSF levels of Apo E were lower in the AD (2.6 +/- 1.5 mg/L; P < .02) and VAD groups (2.5 +/- 0.9 mg/L; P < .002) than in the nondemented group (3.8 +/- 1.7 mg/L). Cerebrospinal fluid levels of Apo E decreased with increasing severity of dementia and with increasing temporal cortical and central frontal atrophy. In nondemented individuals, CSF levels of Apo E decreased with increasing degree of WMLs. Cerebrospinal fluid levels of Apo E were not influenced by the Apo E4 isoform. CONCLUSIONS: Whether our finding of an association between low CSF levels of Apo E and dementia disorders (both degenerative, such as AD, and vascular, such as VAD) is related to the pathogenesis of these disorders or is a secondary consequence of the disease process remains to be established. Although statistical correlations do not give direct evidence of causal relations, the correlations between CSF level of Apo E and severity of dementia and cortical atrophy suggest that CSF level of Apo E follows the disease process.

A one-site, two-state model for the binding of anions in photosystem II.

Photosystem II membranes, dialyzed against a Cl(-)-free buffer to remove bound Cl-, lost about 65% of the control activity. A light-intensity study of the Cl(-)-free membranes showed that all PS II centers were able to evolve oxygen at about 35% of the control rate when measured in Cl(-)-free medium. The Cl(-)-depleted membranes were immediately (< 15 s) reactivated to 85-90% of the original activity by the addition of fairly high concentrations of Cl- (Kd = 0.5 mM), but both Cl- and the activity were promptly lost when the membranes immediately after reactivation were diluted in a Cl(-)-free medium. However, stabilization of Cl(-)-binding could be accomplished by prolonged incubation in the presence of Cl-. The transition to stable binding, followed using 36Cl-, occurred over several minutes. The stable binding was further characterized by a Kd of 20 microM and a t1/2 for dissociation of about 1h [Lindberg et al. (1993) Photosynth. Res. 38, 401-408]. The effects on S2 signals of removal of Cl- were studied using EPR. The depletion of Cl- was accompanied by a shift in intensity toward the g = 4.1 signal at the expense of the multiline signal. When Cl- or Br- but not F- was added to the depleted PS II membranes, the original distribution of the signals was immediately (< 30 s) restored. We propose that Cl(-)-binding responsible for high oxygen-evolution activity and normal EPR properties of the S2 state may occur either as high affinity (Kd = 20 microM) and slowly exchanging (t1/2 = 1 h), or as low affinity (Kd = 0.5 mM) and rapidly exchanging (t1/2 < 15 s). Our results suggest that Br- but not F- has a mode of binding similar to that of Cl-. The high-affinity state is the normal state of binding, but once Cl- has been removed, it will first rebind as low-affinity, rapidly exchanging followed by conversion into a high-affinity, slowly exchanging mode of binding.

15-year longitudinal study of blood pressure and dementia.

BACKGROUND: Vascular causes of dementia may be more common than supposed. Vascular factors may also have a role in late-onset Alzheimer's disease, but the role of hypertension in the development of dementia is unclear. METHODS: As part of the Longitudinal Population Study of 70-year-olds in Göteborg, Sweden, we analysed the relation between blood pressure and the development of dementia in the age intervals 70-75, 75-79, and 79-85 years in those non-demented at age 70 (n = 382). The sample was followed up for 15 years and examined repeatedly with a comprehensive investigation, including a psychiatric and physical examination. a FINDINGS: Participants who developed dementia at age 79-85 had higher systolic blood pressure at age 70 (mean 178 vs 164 mm Hg, p = 0.034) and higher diastolic blood pressure at ages 70 (101 vs 92, p = 0.004) and 75 (97 vs 90, p = 0.022) than those who did not develop dementia. For subtypes of dementia, higher diastolic blood pressure was recorded at age 70 (101, p = 0.019) for those developing Alzheimer's disease and at age 75 (101, p = 0.015) for those developing vascular dementia than for those who did not develop dementia. Participants with white-matter lesions on computed tomography at age 85 had higher blood pressure at age 70 than those without such lesions. Blood pressure declined in the years before dementia onset and was then similar to or lower than that in non-demented individuals. INTERPRETATION: Previously increased blood pressure may increase the risk for dementia by inducing small-vessel disease and white-matter lesions. To what extent the decline in blood pressure before dementia onset is a consequence or a cause of the brain disease remains to be elucidated.

The influence of white matter lesions on neuropsychological functioning in demented and non-demented 85-year-olds.

White matter lesions on computed tomography of the head were studied in relation to neuropsychological functioning in subjects from a representative sample of non-demented (n = 134) and demented (n = 98) 85-year-olds. Non-demented subjects with white matter lesions (n = 46) scored significantly lower in tests of verbal ability (Synonyms), spatial ability (Block Design, Clock Test), perceptual speed (Identical forms), secondary memory (Thurstone Picture Memory), basic arithmetic (Coin Test) and the global cognitive screening test Mini-Mental State Examination than non-demented subjects without white matter lesions (n = 88). Demented subjects with white matter lesions (n = 67) scored significantly lower in tests of spatial ability (Block Design and Clock Test) and secondary memory (free recall in the MIR memory test, Ten-word memory test I and II) and in the Mini-Mental State Examination than demented subjects without white matter lesions (n = 31). It is concluded that white matter lesions contribute to cognitive decline in both non-demented and demented elderly subjects.

Isolation and properties of PS II membrane fragments depleted of the non heme iron center.

The functional properties and the content of non heme iron and cytochrome b559 were investigated by measuring flash induced transient changes of the relative fluorescence quantum yield and applying Mössbauer spectroscopy. It was found that untreated PS II membrane fragments contain a heterogeneous population of two types of non heme iron centers and about 2 cytochrome b559 per PS II. Twofold treatment of these samples with a recently described 'iron depletion' procedure (MacMillan, F., Lendzian, F., Renger, G. and Lubitz, W. (1995) Biochemistry 34, 3144-3156) leads to a complete loss (below the detection limit of Mössbauer spectroscopy) of the non heme iron center while more than 50% of the PS II complexes retain the functional integrity for light induced formation of the 'stable' radical pair Y(OX)(Z) P680Pheo Q(-.)(A). This sample type deprived of virtually all non heme iron in PS II provides a most suitable material for magnetic resonance studies that require an elimination of the interaction between Fe2+ and nearby radicals.

A population-based study of tau protein and ubiquitin in cerebrospinal fluid in 85-year-olds: relation to severity of dementia and cerebral atrophy, but not to the apolipoprotein E4 allele.

Alzheimer's disease (AD) is the most common form of dementia, and is characterized by a degeneration of neurones and their synapses, and a higher number of senile plaques (SP) and neurofibrillary tangles (NFT) compared with that found in non-demented individuals of the same age. NFT are composed of a hyperphosphorylated and ubiquitinated form of tau protein. Previous studies have found that in the cerebrospinal fluid (CSF) both tau and ubiquitin are increased in AD. We examined CSF-tau and CSF-ubiquitin in a population based sample of 85-year-olds, 26 demented (11 with probable Alzheimer's disease (AD), 13 with probable vascular dementia (VAD) and 2 with mixed (AD/VAD) type of dementia) and 35 non-demented individuals. CSF-tau was significantly higher both in the probable AD group (254 +/- 113 pg/mL; P < 0.01), and in the probable VAD group (247 +/- 75 pg/mL; P < 0.005), than in the non-demented group (171 +/- 78 pg/mL), but did not significantly differ between the probable AD and probable VAD groups. In contrast, CSF-ubiquitin did not significantly differ between the probable AD (100 +/- 24 ng/mL), probable VAD (102 +/- 16 ng/mL), and non-demented (97 +/- 27 ng/mL) groups. CSF-tau increased with increasing severity of dementia (P < 0.001), though no such relation was found for CSF-ubiquitin. Neither CSF-tau nor CSF-ubiquitin differed between patients with or without the apolipoprotein E E4 isoform. Higher CSF-tau and CSF-ubiquitin levels were also associated with increasing degree of cortical and central brain atrophy as measured by computerized tomography. The relationships between CSF-tau and severity of dementia and to brain atrophy suggest that CSF-tau may be used as a measure of neuronal/axonal degeneration in patients with dementia. We have previously shown a marked increase in both CSF-tau and CSF-ubiquitin in younger patients with AD and VAD. The less pronounced increase in CSF-tau and the lack of difference in CSF-ubiquitin in older patients suggest that the severity of the degenerative process is less in older than in younger demented patients.

Studies of Ca2+ binding in spinach photosystem II using 45Ca2+.

The Ca(2+)-binding properties of photosystem II were investigated with radioactive 45Ca2+. PS II membranes, isolated from spinach grown on a medium containing 45Ca2+, contained 1.5 Ca2+ per PS II unit. Approximately half of the incorporated radioactivity was lost after incubation for 30 h in nonradioactive buffer. About 1 Ca2+/PS II bound slowly to Ca(2+)-depleted membranes in the presence of the extrinsic 16- and 23-kDa polypeptides in parallel with restoration of oxygen-evolving activity. The binding was heterogeneous with dissociation constants of 60 microM (0.7 Ca2+/PS II) and 1.7 mM (0.3 Ca2+/PS II), respectively, which could reflect different affinities of the dark-stable S-states for Ca2+. The reactivation of oxygen-evolving activity closely followed the binding of Ca2+, showing that a single exchangeable Ca2+ per PS II is sufficient for the water-splitting reaction to function. In PS II, depleted of the 16- and 23-kDa polypeptides, about 0.7 exchangeable Ca2+/PS II binds with a dissociation constant of 26 microM, while 0.3 Ca2+ binds with a much weaker affinity (Kd > 0.5 mM). The rate of binding of Ca2+ in the absence of the two extrinsic polypeptides was significantly higher than with the polypeptides bound. The rate of dissociation of bound Ca2+ in the dark, which had a half-time of about 80 h in intact PS II, increased in the absence of the 16- and 23-kDa polypeptides and showed a further increase after the additional removal of the 33-kDa protein and manganese. The rate of dissociation was also significantly faster in weak light than in the dark regardless of the presence or absence of the 16- and 23-kDa polypeptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Trypsin treatment of reaction centers from Rhodobacter sphaeroides in the dark and under illumination: protein structural changes follow charge separation.

Reaction centers from Rhodobacter sphaeroides R-26 were treated with trypsin in the dark and during illumination (in the charge-separated state). Trypsination resulted in a time-dependent modification of the reaction centers, reflected in changes in the charge recombination rate, in the inhibition of QA- to QB electron transfer, and eventually to inhibition of charge separation. Comparisons of centers with ubiquinone or anthraquinone in the QA site, in which the charge recombination pathways are different, indicate that trypsination affects charges close to the QA(-)-binding site. Studies of light-induced voltage changes from moving charges in reaction centers incorporated in lipid layers on a Teflon film, a technique which allows the discrimination of effects on donor and acceptor sides, indicate that the acceptor side is preferentially degraded by trypsin in the dark. Tryptic digestion during illumination generally resulted in a marked strengthening and acceleration of the effects seen already during dark treatment, but new effects were also detected in gel electrophoretic peptide patterns, in optical spectra, and in the kinetic measurements. Optical kinetic measurements revealed that the donor side of the reaction centers became susceptible to modification by trypsin during illumination as seen in the value of the binding constant for soluble cytochrome c2 which increased by a factor of 2, whereas it was much less affected after trypsination of reaction centers in the dark. The influence of illumination on the rate and mode by which trypsin acts on reaction centers indicates that changes in the protein conformation follow charge separation.(ABSTRACT TRUNCATED AT 250 WORDS)

Middle ear disease and hearing impairment in northern Tanzania. A prevalence study of schoolchildren in the Moshi and Monduli districts.

A total of 854 schoolchildren from one urban and one rural district in northern Tanzania were examined for the presence of middle ear pathology and hearing loss by means of pneumotoscopy and screening audiometry (air conduction). The prevalence of chronic otitis media (COM) was 1.6%, with no difference between urban and rural children. Scarred and sclerotic tympanic membranes were found in 10.9% of urban children and in 15.1% of rural children, the difference being significant. Hearing loss within the speech frequency range in all the children studied was found in 37% of the urban children and in 18% of the rural children. However, the prevalence of hearing loss above 30 dB HL was 3% in both districts. High frequency loss was significantly more common among urban than among rural children. Undetected severe hearing impairment/deafness was found in three children in the rural district, while none was found in the urban district.

The prevalence of white-matter lesions on computed tomography of the brain in demented and nondemented 85-year-olds.

The prevalence of white-matter lesions on computed tomography was studied in a representative sample of 85-year-olds living in Gothenburg, Sweden. The study included a psychiatric examination, interview of a close informant, neuropsychological examination, physical examination, comprehensive laboratory tests, electrocardiogram, chest x-ray, computed tomography scan of the head, and cerebrospinal fluid analysis. The diagnoses of dementia and other mental disorders were made according to DSM-III-R criteria. The prevalence of white-matter lesions in demented subjects was 68.9%, and in nondemented, 33.8%. Their prevalence was not increased in any mental disorder other than dementia. All severities of dementia and the subtypes, Alzheimer's disease, vascular dementia, and other types of dementia, had a significantly higher prevalence of white-matter lesions than did nondemented subjects. The risk for dementia, but not its severity, increased with the severity of these lesions. A stepwise logistic regression analysis showed that both white-matter lesions and infarcts on computed tomography contributed independently to dementia. White-matter changes may be a contributing cause of dementia in the oldest old, or may represent a disease entity of its own. They are important to recognize since they may be potentially preventable, or even treatable.

A population-based study of dementia in 85-year-olds.

BACKGROUND: The aim of this study was to investigate the causes, severity, and prevalence of dementia in a representative sample of 494 85-year-olds living in Gothenburg, Sweden. METHODS: The study included a psychiatric interview, neuropsychological and physical examinations, comprehensive laboratory tests, electrocardiography, chest radiography, computed tomography (CT) of the head, and analysis of cerebrospinal fluid. A person close to each subject was also interviewed. Dementia was defined according to the criteria proposed in the Diagnostic and Statistical Manual of Mental Disorders (third edition, revised), Alzheimer's disease according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association, and vascular dementia according to recently proposed criteria that incorporate information from CT scanning and the patient's neurologic history. RESULTS: The prevalence of dementia was 29.8 percent (147 subjects). The condition was mild in 8.3 percent, moderate in 10.3 percent, and severe in 11.1 percent. There were no significant sex-related differences in prevalence or severity. Of the subjects with dementia, 43.5 percent had Alzheimer's disease, 46.9 percent had vascular dementia (multi-infarct dementia in 34.6 percent, dementia related to cerebral hypoperfusion in 4.1 percent, and mixed dementia in 8.2 percent), and 9.5 percent had dementia due to other causes. The three-year mortality rate was 23.1 percent in the subjects without dementia, 42.2 percent in the patients with Alzheimer's disease, and 66.7 percent in the patients with vascular dementia. Infarcts detected by CT scanning were significantly more common in the subjects with dementia than in those without it (27.9 percent vs. 12.6 percent). CONCLUSIONS: Dementia was present in nearly a third of unselected 85-year-olds in Sweden. Almost half these subjects appeared to have vascular dementia, which may currently be more amenable to prevention or treatment than Alzheimer's disease.