The effects of standing foot-transmitted vibration on self-reported discomfort ratings.

BACKGROUND: Occupational foot-transmitted vibration (FTV) exposure is common in industries like mining, construction, and agriculture, often leading to acute and chronic injuries. Vibration assessments require technical expertise and equipment which can be costly for employers to perform. Alternatively, researchers have observed that self-reported discomfort can be used as an effective indicator of injury risk. OBJECTIVE: This study aimed to investigate the effect of standing FTV exposure on self-reported ratings of discomfort, and whether these subjective ratings differed by body area and exposure frequency. METHODS: Participants (n = 30) were randomly exposed to standing FTV at six frequencies (25, 30, 35, 40, 45, and 50 Hz) for 20-45 seconds. Following each exposure, participants rated discomfort on a scale of 0-9 in four body areas: head and neck (HN), upper body (UB), lower body (LB), and total body. RESULTS: Results indicated that participants experienced the most discomfort in the LB at higher frequencies (p < 0.001), consistent with the resonance of foot structures. The HN discomfort tended to decrease as the exposure frequency increased, although not statistically significant (p > 0.0167). The UB discomfort remained relatively low across all frequencies. CONCLUSIONS: The study suggests a potential connection between resonant frequencies and discomfort, potentially indicating injury risk. Although self-reported discomfort is insufficient for directly assessing injury risk from FTV, it provides a simple method for monitoring potential musculoskeletal risks related to vibration exposure at resonant frequencies. While professional vibration assessment remains necessary, self-reported discomfort may act as an early indicated of vibration-induced injuries, aiding in implementing mitigation strategies.

Effects of continuous lactation and short dry periods on mammary function and animal health.

The dry period is required to facilitate cell turnover in the bovine mammary gland in order to optimize milk yield in the next lactation. Traditionally, an 8-week dry period has been a standard management practice for dairy cows based on retrospective analyses of milk yields following various dry period lengths. However, as milk production per cow has increased, transitioning cows from the nonlactating state to peak milk yield has grown more problematic. This has prompted new studies on dry period requirements for dairy cows. These studies indicate a clear parity effect on dry period requirement. First parity animals require a 60-day dry period, whereas lactations following later parities demonstrate no negative impact with 30-day dry period or even eliminating the dry period when somatotropin (ST) is also used to maintain milk yields. Shortened dry periods in first parity animals were associated with reduced mammary cell turnover during the dry period and early lactation and increased numbers of senescent cells and reduced functionality of lactating alveolar mammary cells postpartum. Use of ST and increased milking frequency postpartum reduced the impact of shortened dry periods. The majority of new intramammary infections occur during the dry period and persist into the following lactation. There is therefore the possibility of altering mastitis incidence by modifying or eliminating the dry period in older parity animals. As the composition of mammary secretions including immunoglobulins may be reduced when the dry period is reduced or eliminated, there is the possibility that the immune status of cows during the peripartum period is influenced by the length of the dry period.

The management of patients with thyroid eye disease after bilateral orbital 3 wall decompression.

INTRODUCTION: Thyroid eye disease is the most common cause of unilateral and bilateral proptosis in adults. Orbital decompression surgery may cause and/or worsen a pre-existing ocular motility disorder. METHODS: A retrospective review was carried out of all bilateral 3 wall orbital decompressions for severe thyroid eye disease performed between January 2002 and December 2004 by one surgeon. Subsequent surgeries were recorded. RESULTS: Seventy-four patients were identified, 59 (80%) females and 15 (20%) males. Mean age at the time of decompression was 46 years. Fifteen (20%) patients complained of diplopia due to strabismus prior to decompression surgery and 20 (27%) developed new diplopia postsurgery. Twenty patients (27%) required no further intervention following decompression surgery; the remainder underwent an average of 2.5 procedures. Strabismus surgery was performed in 32 (43%) patients. The mean time from the decompression to first strabismus surgery was 12 months. Forty-three (58%) patients underwent lid surgery. The mean time from decompression to first lid surgery was 16 months. CONCLUSION: This study demonstrates how this group of complex patients required multiple surgical procedures within an extended timescale, therefore requiring several in- and outpatient visits.

Abeta deposition and related pathology in an APP x PS1 transgenic mouse model of Alzheimer's disease.

A transgenic mouse bearing mutant transgenes linked to familial forms of Alzheimer's disease (AD) for the amyloid precursor protein and presenilin-1 (TASTPM) showed Abeta plaque deposition and age-related histological changes in associated brain pathology. The Abeta present was of multiple forms, including species with a C-terminus at position 40 or 42, as well as an N-terminus at position 1 or truncated in a pyro-3-glutamate form. Endogenous rodent Abeta was also present in the deposits. Laser capture microdissection extracts showed that multimeric forms of Abeta were present in both plaque and tissue surrounding plaques. Associated with the Abeta deposits was evidence of an inflammatory response characterised by the presence of astrocytes. Also present in close association with the deposits was phosphorylated tau and cathepsin D immunolabelling. The incidence of astrocytes and of phosphorylated tau and cathepsin D load showed that both of these potential disease markers increased in parallel to the age of the mice and with Abeta deposition. Immunohistochemical labelling of neurons in the cortex and hippocampus of TASTPM mice suggested that the areas of Abeta deposition were associated with the loss of neurons. TASTPM mice, therefore, exhibit a number of the pathological characteristics of disease progression in AD and may provide a means for assessment of novel therapeutic agents directed towards modifying or halting disease progression.

Evaluation of continuous lactation and increased milking frequency on milk production and mammary cell turnover in primiparous Holstein cows.

We hypothesized that early-lactation increased milking frequency, in combination with bovine somatotropin (bST), would improve milk yield in continuously milked (CM) primiparous glands through greater mammary epithelial cell (MEC) function, proliferation, and reduced apoptosis (cell turnover). Primiparous cows were randomly assigned to a 2 x 2 x 2 factorial with a split-plot design to either a continuous bST (+bST, n = 4) or no bST (-bST, n = 4) treatment throughout the study. Within each animal, udder halves were randomly assigned to either a CM or a 60-d dry period (control). During late gestation, CM glands were milked twice daily until calving or until spontaneous dry-off. At calving, cows were milked either twice or 4 times daily and udder-half milk yield was recorded until 30 d postpartum. Mammary biopsies were conducted on -19 +/- 13, -8 +/- 6, +2, +7, and +20 d relative to calving. Postpartum milk yield was reduced in CM udder halves. Reduced milk yield in CM half udders from cows administered bST and milked 4 times daily was 35% compared with 65% in CM half udders in cows not provided bST and milked twice daily. Proliferation of MEC tended to be greater in control vs. CM tissue at 8 +/- 6 d prepartum. Mammary epithelial cell proliferation was greater during the prepartum period (d -19, -8) compared with postpartum time points (d 2, 7, 20). Apoptosis of MEC was not affected by dry period length, but was elevated during the first 7 d postpartum compared with levels measured at -19, -8, and 20 d. Bovine somatotropin did not alter MEC turnover in primiparous CM or control glands. The use of increased milking frequency and bST alleviated, but did not prevent, reductions in milk yield of CM primiparous cows.

Baclofen for patients with congenital periodic alternating nystagmus.

PURPOSE: To describe the clinical effect of baclofen on a group of patients with congenital periodic alternating nystagmus. METHODS: A retrospective review of case notes was carried out of all patients with congenital periodic alternating nystagmus (PAN) treated with baclofen between 1999 and 2004. Eight patients were identified, 6 males and 2 females with a mean age of 21 years (range 9 to 34 years). Clinical data were recorded for all patients pre- and post-treatment with the GABA agonist baclofen. Adverse effects of the treatment were recorded and a questionnaire was constructed to evaluate patient satisfaction with the treatment. RESULTS: All 8 patients had an abnormal head posture (AHP) before treatment which improved following treatment in 4 patients, one of whom had recurrence following treatment withdrawal. Binocular Snellen visual acuity (VA) improved by one line in 4 cases, while none of the other 4 patients suffered any loss of vision from the treatment. Three of the eight patients have continued on treatment long-term, in one case for 6 years. In the other five, treatment was withdrawn due to side effects in 4 cases, and in the fifth due to a lack of effect. The most commonly reported side effect was drowsiness, which occurred in 3 patients. Using a patient-centered survey, complete responses were obtained from 6 of the 8 patients treated. Five patients were either pleased or very pleased that they had tried the treatment. The reasons given were: improved vision or head posture, an appreciation of slowing of ocular movements, improved cosmesis and improved confidence. CONCLUSIONS: Baclofen may be effective in a select group of patients with congenital PAN and a trial of treatment may be worthwhile, prior to considering surgical intervention in this condition.

Does Botulinum toxin have a role in the treatment of small-angle esotropia?

A retrospective review of the Toxin Clinic database was carried out over an 18-year period. We identified 68 patients with esotropia of 20 prism dioptres and under who were treated with Botulinum toxin. There were 47 females and 21 males, with a mean age of 34 years (range 11-78 years). Thirty-two (47%) patients had residual esotropia, 20 (29%) had primary esotropia, 11 (16%) had consecutive esotropia, 4 (6%) had secondary esotropia and 1 (1.5%) had a decompensating esophoria. The mean pre-toxin angle was 16 prism dioptres (range 6-20). A total of 434 injections were given, with an average of 6 per patient (range 1-36). Forty-five (66%) patients underwent continued toxin treatment with an interval of 3 to 31 months. Thirteen (19%) patients achieved long-term benefit from only one injection. Seven were unable to demonstrate binocular vision pre-injection but demonstrated it post-injection. Following an initial injection, nine (13%) patients proceeded to surgery. Botulinum toxin was a successful treatment for these patients and was well tolerated, with no side effects. It appears to have a definite role in the treatment of small-angle esotropia.

The incidence of strabismus and refractive error in patients with blepharophimosis, ptosis and epicanthus inversus syndrome (BPES).

A retrospective review was carried out of 204 patients with blepharophimosis, (blepharo) ptosis and epicanthus inversus syndrome (BPES). Of these, 94 (46%) had an autosomal dominant family history of BPES. Forty (20%) had manifest strabismus. Of these, 28 (70%) had esotropia, 10 (25%) had exotropia and 2 (5%) had hypertropia. Twelve (6%) patients had nystagmus. Seventy (34%) patients had a significant refractive error requiring spectacles. Twenty-one (30%) of these patients had anisometropic hypermetropia and 24 (34%) had anisometropic myopia. Forty-three patients had bilateral amblyopia and 40 had unilateral amblyopia, with 26 (65%) of these undergoing occlusion treatment. Of these, 14 had strabismus and refractive error, 7 refractive error only, 2 strabismus only and 3 neither refractive error nor strabismus. We conclude that there is a higher incidence of strabismus and refractive error in patients with BPES than in the normal population.

Role of botulinum toxin A in surgically overcorrected exotropia.

PURPOSE: The purpose of this study was to define the role of botulinum toxin type A (BTXA) in surgically overcorrected exotropia. METHODS: A retrospective review was performed using the BTXA clinic database of more than 3500 patients to identify patients with a consecutive esotropia. RESULTS: Sixty patients met the inclusion criteria; the patients' ages ranged from 5 to 80 years. Before toxin treatment, an average of 1.8 operations had been performed per patient. The mean distance deviation was 17 PD base out and near deviation was 18 PD base out. The time from the last operation to an injection of BTXA averaged 28.3 months. We divided our patient population into 2 groups: those with fusion potential and those with no expected fusion potential. Of the 36 patients with fusion potential, 15 patients achieved and maintained good ocular alignment and resolution of their diplopia with an injection of BTXA. In the 24 patients with no expected fusion potential, 4 patients (17%) achieved and maintained good alignment with an injection of BTXA. Although they were not cured, 10 additional patients chose to have repeated BTXA injections to maintain their ocular alignment, whereas only 2 patients required occlusive methods to eradicate intractable diplopia. Five patients had additional surgery, of which 3 patients obtained a functional result. CONCLUSIONS: BTXA has a role in surgically overcorrected exotropia for patients in whom a functional result may be obtained. BTXA is of less value for patients with poor binocular function. It has proved especially useful as a treatment given only once for 42% of patients who could regain high-quality stereopsis. The safety and ease of administration of this treatment add to its merit.

The role of botulinum toxin A in acute-onset esotropia.

OBJECTIVE: To establish the effectiveness of botulinum toxin A (BTXA) in the treatment of patients with acute acquired concomitant esotropia. DESIGN: Retrospective, interventional, noncomparative case series. PARTICIPANTS: Fourteen patients presenting to the Strabismus and Pediatric Service at Moorfields Eye Hospital with acute-onset esotropia over a 6-year period (1991-1997). INTERVENTION: 2.5 units of BTXA injected into the unilateral medial rectus muscle of the deviating eye under electromyographic control. MAIN OUTCOME MEASURES: Pre- and postinjection angle of deviation, pre- and postinjection stereopsis, final level of stereopsis achieved, and whether corrective squint surgery was later required. RESULTS: Fourteen patients were identified, of whom eight were male and six female. The mean age at presentation was 5.4 years, and the average time from onset to attending the clinic was 18 weeks. The mean time from onset of acute esotropia to injection was 32.5 weeks. All patients, except one, showed considerable improvement in their manifest deviation after one injection of BTXA. Eight patients (57%) maintained high-grade stereopsis of 120 seconds of arc or better and long-term ocular alignment with toxin treatment alone. In total, 11 patients (79%) gained improved stereopsis and maintained satisfactory ocular alignment with toxin therapy and did not require squint surgery. Two patients (14%) did not maintain a stable ocular position after toxin treatment and later required squint surgery, gaining good ocular alignment and high-grade stereopsis. The one patient who did not respond to the initial BTXA injection refused all further treatment. The mean follow-up time was 22 months. CONCLUSIONS: Botulinum toxin therapy has a definite role in the treatment of children with acute-onset esotropia. It may well obviate the need for squint surgery. The safety and ease of administration of this treatment add to its merits.