Gamification and neurological motor rehabilitation in children and adolescents: a systematic review

INTRODUCTION

Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment.

METHODS

We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale.

RESULTS

From a total of 469 studies, 11 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6 studies), followed by developmental coordination disorder (3), neurological gait disorders (1), and neurological impairment of balance and coordination (1).

CONCLUSION

The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage.

Translation, cross-cultural adaptation and validation of the Rett syndrome motor evaluation scale (RESMES): Spanish version

OBJECTIVE

To develop a Spanish version of the Rett Syndrome Motor Evaluation Scale (RESMES) for the locomotor function of Rett Syndrome (RTT) using a transcultural methodology.

METHODS

The RESMES was cross-culturally adaptated and validated in the Spanish language (RESMES-sp). This study was divided into two well-differentiated phases: 1) a cross-cultural translation and adaptation; 2) psychometric characteristics analysis of the RESMES-sp (reliability, test-retest, construct validity, criteria validity, error measurements). For criteria validity, PAINAD questionnaire, the scoliosis values and PedsQL™, were used.

RESULTS

A total of 63 girls and women diagnosed with RTT participated in this validation study. The total value of the RESMES-sp correlates significantly with all its dimensions, with the correlation value oscillating between 0.645 and 0.939. The correlation value with PAINAD ranges between 0.439 and 0.805; the scoliosis values ranges between 0.245 and 0.564; with PedsQOL™ questionnaire, the correlation values range between 0.273 and 0.663 for the PedsQL™ dimensions, and between 0.447 and 0.648 for the total value of PedsQOL™ questionnaire. The reliability values of Crombach's alpha ranged between 0.897 and 0.998 for the intra-observer analyses and between 0.904 and 0.998 for the inter-observer reliability. The SEM showed a value of 2,829, while the MDC90 showed a value of 6601. The Exploratory Factor Analysis showed 6 factors and values of variance of 86.163%.

CONCLUSIONS

The Spanish version of the RESMES is a reliable and valid tool for the functional assessment and follow-up of patients with RTT.

Cerebral amyloid angiopathy-related inflammation: clinical features and treatment response in a case series

INTRODUCTION

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is an entity characterised by an inflammatory response to β-amyloid deposition in the walls of cerebral microvessels.

METHODS

We conducted a retrospective review of a series of patients with a diagnosis of CAA-ri according to histopathological study findings or clinical-radiological diagnostic criteria.

RESULTS

The study included 7 patients (5 men) with a mean age of 79 years. Disease onset was acute or subacute in 6 patients. The most frequent symptoms were cognitive impairment (n = 6), behavioural alterations (n = 5), epileptic seizures (n = 5), focal neurological signs (n = 4), and headache (n = 2). Cerebrospinal fluid was abnormal in 3 patients (lymphocytic pleocytosis and high protein levels). The most frequent MRI findings were microbleeds (n = 7), subcortical white matter hyperintensities on T2-FLAIR sequences (n = 7), and leptomeningeal enhancement (n = 6). Lesions were bilateral in 3 patients and most frequently involved the parieto-occipital region (n = 5). Amyloid PET studies were performed in 2 patients, one of whom showed pathological findings. Two patients underwent brain biopsy, which confirmed diagnosis. All patients received immunosuppressive therapy. An initially favourable clinical-radiological response was observed in all cases, with 2 patients presenting radiological recurrence after treatment withdrawal, with a subsequent improvement after treatment was resumed.

CONCLUSIONS

Early diagnosis of CAA-ri is essential: early treatment has been shown to improve prognosis and reduce the risk of recurrence. Although a histopathological study is needed to confirm diagnosis, clinical-radiological criteria enable diagnosis without biopsy.

Limbic encephalitis secondary to neuro-Behcet disease: an uncommon presentation

INTRODUCTION

Limbic encephalitis (LE) can have a wide range of etiologies, most frequently infectious (especially viral) or autoimmune. Behcet's disease (BD) can present with heterogeneous neurological manifestations. However, LE is not considered a typical presentation of neuro-Behcet's disease (NBD).

CASE REPORT

A 40-years-old male presented with new-onset subacute headaches, memory problems and apathy. A review of systems revealed an unrecorded past history of recurrent oral sores for years, recent malaise and fever, as well as an episode of bilateral panuveitis four months before presentation. His general and neurologic examination revealed slight fever, an isolated oral aphtha, anterograde amnesia and signs of bilateral retinal vasculitis. Brain magnetic resonance imaging displayed a pattern of limbic meningoencephalitis, and his cerebrospinal fluid showed mononuclear inflammation. The patient met BD diagnostic criteria. Considering LE is a very rare presentation of NBD, alternative etiologies were thoroughly assessed and excluded, including infectious, autoimmune and paraneoplastic encephalitis. Therefore, he was diagnosed with NBD, and he recovered well after immunosuppression.

DISCUSSION

Only two cases of NBD presenting with LE have been previously reported. We report a third case of this rare presentation and compare it with the previous two. We aim to highlight this association and contribute to enlarge the rich clinical spectrum of NBD.

Fatal intracerebral haemorrhage associated with thrombosis with thrombocytopenia syndrome after ChAdOx1-S vaccine

INTRODUCTION

The COVID-19 pandemic has had a devastating impact on health, society and economics worldwide. Therefore, vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have recently emerged as an important measure to fight the pandemic. ChAdOx1-S (Oxford-AstraZeneca) is an adenovirus-vectored vaccine that expresses the SARS-CoV-2 spike protein. It shows an acceptable safety profile. Nevertheless, several cases of unusual thrombosis and thrombocytopenia have been reported after initial vaccination with ChAdOx1-S mimicking autoimmune heparin-induced thrombocytopenia. This condition has been called thrombosis with thrombocytopenia syndrome (TTS) and complications such as intracerebral haemorrhage have been described.

CASE REPORT

We present a case of intracerebral haemorrhage after ChAdOx1-S vaccination. Middle-aged patient with no prior medical history was seen in the emergency room 16 days after the first dose of ChAdOx1-S vaccine with sudden onset left hemiplegia and severe holocranial oppressive headache. She did not receive heparin treatment in the previous 100 days. Blood test showed moderate thrombocytopenia and a right frontal lobar haemorrhage was seen on computed tomography scan, computed tomography venography was negative for thrombosis. The presence of antibodies against platelet factor 4 was confirmed. The patient's neurological condition progressively worsened. She developed a treatment resistant intracranial hypertension syndrome and she died three weeks later.

CONCLUSIONS

TTS is a rare adverse effect of ChAdOx1-S vaccine, defined by the presence of thrombosis in uncommon locations. In our case we report an spontaneous intracerebral haemorrhage probable due to the thrombocytopenia related to probable TTS. It represents a rare clinical presentation of TTS.

[Clinical results in arthroscopic rotator cuff repair with the modified Mason-Allen technique]

INTRODUCTION

rotator cuff tears are one of the most common shoulder injuries. The treatment of choice is arthroscopic repair with the use of anchors. The modified Mason-Allen technique, which combines the benefits of suture bridge and mattress sutures, has shown satisfactory results. This study aims to report and analyze the clinical results using these suture techniques in rotator cuff tears.

RESULTS

preoperative mean active flexion 126o, 169o at three months, 175o at 12 months (p < 0.0001), active abduction 98o, 159o at three months and 167o at 12 months (p < 0.0001), internal rotation preoperative value 4.4 ± 3, at three months 7.1 ± 1.7 (p < 0.05) and 12 months 7.6 ± 1.1 (p < 0.001). Constant score 45.76 ± 16.35 (p < 0.0001) at three months 87.27 ± 10.94 and 12 months 91.30 ± 6.00. SSV 41.30 ± 20.89, three months 81.43 ± 18.31 and 12 months 94.37 ± 6.90 (p = 0.0001). Initial mean VAS 6.6 ± 1.6 and 12 months 0.63 ± 1.02 (p < 0.0001).

CONCLUSION

in rotator cuff tears, using a single row with the modified Mason-Allen technique is a recommended and replicable option with satisfactory results and statistically significant clinical improvement at three and 12 months post-surgery.

Outcome measurement instruments in Rett syndrome: A systematic review

OBJECTIVE

The aim of the study was to identify and characterize outcome measures for objective and subjective assessment in persons with Rett syndrome (RS).

METHODS

A systematic review was conducted consulting the EBSCO, Cochrane, Web of Science, Scielo, MEDLINE and PsycINFO databases for published studies describing the use of patient-reported outcome measures (PROMs) and other outcome measures in persons with RS. Validation studies and observational studies were included. The PROMs were first described, and then the measurement properties were evaluated using predefined criteria according to the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN). The outcome measures were then grouped according to the International Classification of Functioning, Disability and Health (ICF) to establish a relationship between outcome measures and ICF domains.

RESULTS

Twenty out of 2327 articles were appraised, and seventeen different outcome measures were identified and described. Ten outcome measures corresponded to evaluation questionnaires, while the remaining seven assessed functional outcomes: walking distance, physical activity level and ability to interact visually. A relation between these outcome measures that assess RS and the ICF allows understanding that most of the instruments (fifteen) include the assessment of activity limitations.

CONCLUSIONS

The findings of this study seem to be promising for their use by clinicians and researchers, although they have methodological limitations. The accuracy and quality of these individual outcome measures should continue to be assessed in an attempt to gather a consensus on the best tools used in RS.

Gamification and neurological motor rehabilitation in children and adolescents: A systematic review

INTRODUCTION

Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment.

METHODS

We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale.

RESULTS

From a total of 469 studies, 10 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6studies), followed by developmental coordination disorder (3), and neurological impairment of balance and coordination (1).

CONCLUSION

The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage.

Cerebral amyloid angiopathy-related inflammation: clinical features and treatment response in a case series

INTRODUCTION

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is an entity characterised by an inflammatory response to β-amyloid deposition in the walls of cerebral microvessels.

METHODS

We conducted a retrospective review of a series of patients with a diagnosis of CAA-ri according to histopathological study findings or clinical-radiological diagnostic criteria.

RESULTS

The study included 7 patients (5 men) with a mean age of 79 years. Disease onset was acute or subacute in 6 patients. The most frequent symptoms were cognitive impairment (n = 6), behavioural alterations (n = 5), epileptic seizures (n = 5), focal neurological signs (n = 4), and headache (n = 2). Cerebrospinal fluid was abnormal in 3 patients (lymphocytic pleocytosis and high protein levels). The most frequent MRI findings were microbleeds (n = 7), subcortical white matter hyperintensities on T2-FLAIR sequences (n = 7), and leptomeningeal enhancement (n = 6). Lesions were bilateral in 3 patients and most frequently involved the parieto-occipital region (n = 5). Amyloid PET studies were performed in 2 patients, one of whom showed pathological findings. Two patients underwent brain biopsy, which confirmed diagnosis. All patients received immunosuppressive therapy. An initially favourable clinical-radiological response was observed in all cases, with 2 patients presenting radiological recurrence after treatment withdrawal, with a subsequent improvement after treatment was resumed.

CONCLUSIONS

Early diagnosis of CAA-ri is essential: early treatment has been shown to improve prognosis and reduce the risk of recurrence. Although a histopathological study is needed to confirm diagnosis, clinical-radiological criteria enable diagnosis without biopsy.

TARDBP mutation associated with semantic variant primary progressive aphasia, case report and review of the literature

Semantic variant primary progressive aphasia (svPPA) is a clinical syndrome included in the frontotemporal dementia (FTD) spectrum. Unlike other forms of FTD, it is sporadic in the majority of cases and not commonly associated with motor neuron disease (MND). We describe a case of svPPA associated with MND in the same family, due to a mutation of the transactive response DNA binding protein (TARDBP) gene, and review the literature.

Slowly progressive behavioral frontotemporal dementia with C9orf72 mutation. Case report and review of the literature

We present a 86-year-old woman without relevant medical history and two brothers who died by dementia, who started at 55 years with depression and personality changes with ongoing worsening (>30 years) and functional decline. Screening dementia blood test and brain magnetic resonance imaging did not show results that pointed to a secondary cause. The patient met the diagnostic criteria for possible behavioral frontotemporal dementia with a slow progression (bvFTD-SP), suggesting a benign variant. A genetic study confirmed a C9ORF72 hexanucleotide expansion, making this the sixth case mentioned in the literature. We review and discuss the other cases described previously.

[Severe hand injury due to a high-energy gunshot projectile treated with arthrodesis of the carpus, synthetic bone graft and external fixators. Case report]

BACKGROUND

The incidence of hand gunshot wounds in civil patients has increased in recent years; it causes long-term or permanent disability and has a personal, social and economic impact. Severe hand injuries include: involvement of the greater palmar arch, fracture of two or more carpal bones, irreducible palmar dislocations, articular fractures of the distal radius, and neurovascular injuries. All of these injuries require multiple surgical procedures for the management of soft and musculoskeletal tissues.

METHODS

We report the case of a patient with a Gustilo and Anderson grade IIIB open fracture of the right carpal bones caused by a gunshot projectile. He was treated with arthrodesis of the carpus using a synthetic graft, external fixation and rotation of a fasciocutaneous flap.

RESULTS

The patient underwent surgical treatment of the carpal injury that consisted of Gustilo and Anderson grade IIIB open fracture of all carpal bones caused by a gunshot projectile. Surgery included arthrodesis of the carpus with a synthetic graft, stabilization with an external fixator, and a fasciocutaneous graft as skin cover. The clinical course according to the DASH scale had a score of 14.2 and the Michigan Hand score was 70, with a 12-month follow-up.

CONCLUSIONS

Treatment with external fixation plus arthrodesis of the carpus with a synthetic graft and skin cover using a flap provided a good functional result in a patient who sustained a gunshot wound.

[Experience with the negative pressure closure system of chronic wounds in pediatric patients]

OBJECTIVE

To show the results and advantages of using the negative pressure closure system in a pediatric population with infections and wound closure defects.

MATERIAL AND METHODS

A retrospective analysis was conducted on pediatric patients in whom the VAC(®) negative pressure wound closure system was used in the Shriners Hospital for Children, Mexico, from January 2008 to December 2012. We were able to include 8 patients treated with this system. We evaluated the cause for use, wound colonizing microorganism, number of days of stay at the hospital, number of times applied, interval of application, and number of days in the hospital until discharge after VAC(®) application, and final treatment.

RESULTS

The average days after VAC aplication till discharge was 13.7 days. The final treatment in 7 of the 8 patients was direct closure or application of skin grafts for closure of the wounds.

DISCUSSION

Through this study we were able to observe that, after the application of this treatment, there was an increase in the granulation tissue at the wounds, as well as resolution of the infection.

CONCLUSIONS

We were able to confirm the efficiency of this treatment in controlling the infection and decreasing skin defects, allowing an easier and earlier wound closure.

Activation of rye 5RL neocentromere by an organophosphate pesticide

An interstitial constriction located on the long arm of rye chromosome 5R (5RL) shows neocentromeric activity at meiosis. In some meiocytes this region is strongly stretched orienting with the true centromere to opposite poles at metaphase I, and keeping sister chromatid cohesion at anaphase I. We found previously that the frequency of neocentric activity varied dramatically in different generations suggesting the effect of environmental factors. Here we studied the behavior of the 5RL neocentromere in mono- and ditelosomic 5RL, and mono-, and disomic 5R wheat-rye addition lines, untreated and treated with an organophosphate pesticide. The treated plants form neocentromeres with an about 4.5-fold increased frequency compared to untreated ones, demonstrating that the pesticide promotes neocentric activity. The neocentromere was activated irrespectively of the pairing configuration or the presence of a complete or truncated 5R centromere. Fluorescence in situ hybridization (FISH) with 2 repetitive sequences (UCM600 and pSc119.2) present at the constriction showed kinetic activity at several locations within this region. Immunostaining with anti-α-tubulin showed that treated plants have abnormal spindles in 46% of the metaphase I cells, indicating that disturbances in spindle formation might promote neocentromere activation.

Neocentrics and holokinetics (holocentrics): chromosomes out of the centromeric rules

The centromere appears as a single constriction at mitotic metaphase in most eukaryotic chromosomes. Holokinetic chromosomes are the exception to this rule because they do not show any centromeric constrictions. Holokinetic chromosomes are usually forgotten in most reviews about centromeres, despite their presence in a number of animal and plant species. They are generally linked to very intriguing and unusual mechanisms of mitosis and meiosis. Holokinetic chromosomes differ from monocentric chromosomes not only in the extension of the kinetochore plate, but also in many other peculiar karyological features, which could be understood as the 'holokinetic syndrome' that is reviewed in detail. Together with holokinetic chromosomes we review neocentromeric activity, a similarly intriguing case of regions able to pull chromosomes towards the poles without showing the main components reported to be essential to centromeric function. A neocentromere is a chromosomal region different from the true centromere in structure, DNA sequence and location, but is able to lead chromosomes to the cell poles in special circumstances. Neocentromeres have been reported in plants and animals showing different features. Both in humans and Drosophila, neocentric activity appears in somatic cells with defective chromosomes lacking a functional centromere. In most cases in plants, neocentromeres appear in chromosomes which have normal centromeres, but are active only during meiosis. Because of examples such as spontaneous or induced neocentromeres and holokinetic chromosomes, it is becoming less surprising that different structures and DNA sequences of centromeres appear in evolution.

Clinical effect of deep water running on non-specific low back pain: A randomised trial

Objectives: To evaluate clinical effect of deep water running(DW R) on non-specific low back pain. Outcome measures were pain, disability,general health and physical fitness.  Materials and methods: Experimental, randomized,  controlled trial involving 46 persons with CLBP over 15 weekswith two experimental processes, each three times a week. Evidence-basedProgram (EBP, personalized physical exercise program, manual therapy andhealth educa tion) was the common process to which was added 20 minutes ofpersonalized intensity DW R at the aerobic threshold. Measurements were made at the beginning and end of the studyof pain, disability, general health and physical fitness.  R esults: The pain of CLBP were homogeneous at baseline.Significant changes between group were don’t found for pain in favour of the EBP+DW R group (p<0.3). The within-group differences were highly significant for all clinical and functional variables. The effect was clinically relevant forpain in the EBP+DW R group (0.70) and in the EBP group (0.58), and for disability degree it was also relevant in theEBP+DW R group (0.48) and relevant for the EBP group (0.36). Conclusion: Significant improvement was seen inCLBP when EBP was complemented with the high-intensity exercise of DW R.

Chromosomes with a life of their own

B chromosomes (Bs) can be described as 'passengers in the genome', a term that has been used for the repetitive DNA which comprises the bulk of the genome in large genome species, except that Bs have a life of their own as independent chromosomes. As with retrotransposons they can accumulate in number, but in this case by various processes of mitotic or meiotic drive, based on their own autonomous ways of using spindles, especially in the gametophyte phase of the life cycle of flowering plants. This selfish property of drive ensures their survival and spread in natural populations, even against a gradient of harmful effects on the host plant phenotype. Bs are inhabitants of the nucleus and they are subject to control by 'genes' in the A chromosome (As) complement. This interaction with the As, together with the balance between drive and harmful effects makes a dynamic system in the life of a B chromosome, notwithstanding the fact that we are only now beginning to unravel the story in a few favoured species. In this review we concentrate mainly on recent developments in the Bs of rye and maize, two of the species currently receiving most attention. We focus on their population dynamics and on the molecular basis of their structural organisation and mechanisms of drive, as well as on their mode of origin and potential applications in plant biotechnology.

Meiotic loss of the B chromosomes of maize is influenced by the B univalent co-orientation and the TR-1 knob constitution of the A chromosomes

The suppression of meiotic loss when the maize B chromosomes are unpaired is genetically determined. Two genotypes were selected in 1B x 0B crosses: the H line where the B transmission rate is Mendelian (50%) and the L line where the B is present in only about 40% of the progeny. Using the ZmBs probe located at the centromere and at the distal portion of the B chromosome in FISH, we found that the centromeric and telomeric ends of the B univalent co-orient at metaphase I. This feature seems to promote proper centromere orientation causing the lack of meiotic loss of the unpaired B. The co-orientation was observed in both lines, however in the L line the B univalents were not always properly oriented, showing amphitelic orientation in about 25% of the metaphase I cells. We also studied plants of the H and L lines with FISH to test the possible relation between the knob constitution and B loss. It has been found that the plants of both lines are similarly variable for the 180-bp knob repeat, but they differ in the TR-1 350-bp repeat, the L line having more TR-1 knobs. The use of a 45S rDNA probe which labels chromosome 6, allowed us to determine that this chromosome shows the main variability between the two lines: the L line has TR-1 in both arms, showing a large TR-1 knob on the long arm. The H line has only one, generally located on the short arm besides the NOR.

The high variability of subtelomeric heterochromatin and connections between nonhomologous chromosomes, suggest frequent ectopic recombination in rye meiocytes

The position of telomeres, centromeres and subtelomeric heterochromatin (SH) has been studied by FISH in rye meiocytes. We compare the morphology of the signals from zygotene to telophase II mainly to determine differences in SH and telomere positions between plants with and without neocentromeres. Plants from two varieties were used: Paldang showing neocentromeres, and Puyo without neocentromeres but with two B chromosomes. In both varieties, at zygotene and pachytene the SH is observed forming clumps often including two or more bivalent ends. At diplotene the SH is stretched suggesting that it is close to the nuclear envelope. In these cases, the telomere signals are not stretched and lay behind the SH. Frequently, two or more bivalents are joined by conspicuous SH connections at diplotene strongly suggesting ectopic recombination. Probably as a result, differential distribution of the SH between recombinant homologues or the whole meiotic products is observed. From diplotene onwards, the large heterochromatic blocks cover the telomeres, the SH being the morphological end of the bivalents, both in plants with or without neocentromeres. The Bs are tightly associated only at the telomeric end of the long arm from diplotene to metaphase I. The high variability between homologous chromosomes and the frequent nonhomologous bindings of SH, strongly suggest that rye SH is in dynamic state and frequently changes in chromosome position during meiosis.

Movement ability of rye terminal neocentromeres

Rye terminal neocentromeres were analyzed in various aspects. Plants with and without neocentromeres were crossed to determine the possible genetic control on their formation. The segregation obtained in our work is consistent with the hypothesis of two trans-acting genes determining neocentric activity in such a way that individuals with no neocentromeres at all would carry all non-activating alleles, whereas one activating allele might permit the activation of a few neocentromeres. Individuals with four activating alleles would show the maximum frequency of neocentromeres per cell. Anti-tubulin immunolabelling was used to visualize the interaction between the neocentromeres and the microtubules. In most cases an end-on interaction between neocentromeres and microtubules was observed, but a few neocentromeres were observed free of them. Spikes were irradiated at early meiosis to determine whether acentric fragments carrying subtelomeric heterochromatin were able to behave as neocentromeres. In no case were acentric fragments observed to form an extension polewards as they did in whole chromosomes. Broken chromosomes joined by a thin thread of chromatin to the centromeric region

The parasitic effects of rye B chromosomes might be beneficial in the long term

Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.

One gene determines maize B chromosome accumulation by preferential fertilisation; another gene(s) determines their meiotic loss

Genotypes of high (H(m)) and low (L(m)) male B transmission rate (B-TR) were obtained. B-TR segregation in the F2 is reported, showing that the H(m) and L(m) lines differ in a single locus we call mBt (male B transmission), controlling B preferential fertilisation in maize. The egg cells control which one of the sperm nuclei is going to fertilise them, mBt(h) egg cells being preferentially fertilised by the sperm nucleus carrying the supernumerary B chromosomes (Bs). It is hypothesised that the mBt gene is involved in the normal fertilisation of maize but the parasitic Bs take advantage of the mBt(h) allele to increase their own transmission. Selection was also carried out when the Bs were transmitted on the female side (H(f) and L(f) lines). The F1 hybrids show that the gene(s) that we call fBt (female B transmission), controlling female B-TR, is located on the A chromosomes acting at diploid level, the fBt(l) allele(s) for low transmission being dominant. This allele causes the loss of Bs at meiosis, which is shown using a specific B molecular probe to determine B presence/absence in microspores of both lines and hybrids. Maize Bs are a nice example of intragenome conflict, because the mBt and fBt loci are a polymorphic system of attack and defence between A and B chromosomes.

Is maize B chromosome preferential fertilization controlled by a single gene?

In previous work, genotypes for high and low B chromosome transmission rate were selected from a native race of maize. It was demonstrated that the B transmission is genetically controlled. The present work reports the fourth and fifth generations of selection and the F1 hybrids between the lines. The native B is characterized by a constant behaviour, with normal meiosis and nondisjunction in 100% of postmeiotic mitosis. It is concluded that genetic variation for B transmission between the selected lines is due to the preferential fertilization process. The F1 hybrids show intermediate B transmission rate between the lines. They are uniform, the variance of the selected character being one order of magnitude lower than that of the native population. In addition, 0B x 2B and 2B x 2B crosses were made to study the effect of the presence of B chromosomes in the female parent, resulting in non-significant differences. Several crosses were made both in Buenos Aires and in Madrid to compare the possible environmental effect, but significant differences were not found. Our results are consistent with the hypothesis of a single major gene controlling B transmission rate in maize, which acts in the egg cell at the haploid level during fertilization. It is also hypothesized that maize Bs use the normal maize fertilization process to promote their own transmission.

Chromosome nondisjunction and instabilities in tapetal cells are affected by B chromosomes in maize

Abnormal mitosis occurs in maize tapetum, producing binucleate cells that later disintegrate, following a pattern of programmed cell death. FISH allowed us to observe chromosome nondisjunction and micronucleus formation in binucleate cells, using DNA probes specific to B chromosomes (B's), knobbed chromosomes, and the chromosome 6 (NOR) of maize. All chromosome types seem to be involved in micronucleus formation, but the B's form more micronuclei than do knobbed chromosomes and knobbed chromosomes form more than do chromosomes without knobs. Micronuclei were more frequent in 1B plants and in a genotype selected for low B transmission rate. Nondisjunction was observed in all types of FISH-labeled chromosomes. In addition, unlabeled bridges and delayed chromatids were observed in the last telophase before binucleate cell formation, suggesting that nondisjunction might occur in all chromosomes of the maize complement. B nondisjunction is known to occur in the second pollen mitosis and in the endosperm, but it was not previously reported in other tissues. This is also a new report of nondisjunction of chromosomes of the normal set (A's) in tapetal cells. Our results support the conclusion that nondisjunction and micronucleus formation are regular events in the process of the tapetal cell death program, but B's strongly increase A chromosome instability.

[Meta-analysis of the treatment of benign paroxysmal positional vertigo by Epley and Semont maneuvers]

OBJECTIVE

To determine the effectiveness of Epley and Semont maneuvers in treating benign paroxysmal positional vertigo (BPPV).

DESIGN

Systematic search of the medical literature to identify studies that used Epley or Semont maneuvers in randomized controlled trials to treat BPP'V. Studies were examined blind and the results of the studies with a satisfactory methodological quality were pooled.

SUBJECTS

Four studies of adults with a clinical diagnosis of BPPV.

MAIN OUTCOME MEASURES

Subjective sensation of vertigo 7 and 30 days after treatment, positional objective nystagmus and vertigo evoked by the Dix-Hallpike test (DHT) 7 and 30 days after treatment.

RESULTS

Seventy percent of Epley maneuver-treated adults and 95% of placebo-treated adults reported new episodes of vertigo at 7 days. Moreover, 100% had a positive DHT (odds ratio 0.11; p = 0. 0072). However, 30 days after treatment 59% of treated adults (Epley or Semont) remained asymptomatic and 89% were unresponsive to DHT. Subjective remission of BPPV occurred in 47% of placebo-treated subjects, but only 27% had a negative DHT (odds ratio 0.05 for Epley maneuver-treated evaluated by DHT).

CONCLUSIONS

The Epley canalith repositioning procedure or Semont maneuver had a significantly higher efficacy rate in patients with BPPV than placebo procedures, but results must be evaluated at 30 days by DHT. DHT is an easy, low-cost and effective method for assessing the outcome of treatment in patients with BPPV.