Climate plays a dominant role over land management in governing soil carbon dynamics in North Western Himalayas

The soil carbon (C) dynamics is strongly influenced by climate and land-use patterns in the Himalayas. Therefore, soils under five prominent land use [e.g., maize (Zea mays), horticulture, natural forest, grassland, and wasteland] were sampled down up to 30 cm depth under two climatic conditions viz., temperate and subtropical to assess the impacts of climate and landuse on soil C dynamics. Results demonstrated that irrespective of land use, temperate soil contains 30.66% higher C than subtropical soils. Temperate soils under natural forests had the higher total organic carbon (TOC, 21.90 g kg^-1), Walkley-Black carbon (WBC, 16.42 g kg^-1), contents, and stocks (TOC, 66.92 Mg ha^-1 and WBC, 50.24 Mg ha^-1), and total soil organic matter (TSOM, 3.78%) concentration as compared to other land uses like maize, horticulture, grassland, and wasteland. Under both climatic conditions, maize land use had the lowest TOC 9.63, 6.55 g kg^-1 and WBC 7.22, 4.91 g kg^-1 at 0-15 and 15-30 cm soil depth, respectively. Horticulture land use had 62.58 and 62.61% higher TOC and WBC over maize-based land use under subtropical and temperate climatic conditions at 0-30 cm soil depth, respectively. However, soils of maize land use under temperate conditions had ∼2 times more TOC than in subtropical conditions. The study inferred that the C-losses is more in the subtropical soil than in temperate soils. Hence, the subtropical region needs more rigorous adoption of C conservation farming practices than the temperate climatic setting. Although, the adoption of C storing and conserving practices is crucial under both climatic settings to arrest land degradation. Horticultural land uses along with conservation effective soil management practices may be encouraged to restore more soil C and to improve the livelihood security of the hill populace in the North Western Himalayas.

Pattern of Male Hypogonadism and Outcome of Treatment in South Rajasthan

Male reproductive functions are governed by hypothalamic pituitary testicular axis. If any component of this axis malfunctions, then hypogonadism will develop which is characterized by ill-defined secondary sexual features and low serum testosterone. The common patterns seen are primary and secondary testicular failure in the young; and late onset hypogonadism in the elderly. All such cases can be virilized and managed by androgen supplementation. Spermatogenesis can be induced by use of appropriate gonadotropins in selected cases. The aim of the study was to find out the pattern, management and outcome of male hypogonadism.

MATERIAL

It was a prospective questionnaire based observational study, carried out on infertile hypogonadic males, attending medicine outdoor at medical college hospital from January 2015 to December 2020. There were 50 males with hypogonadic features, cases of late onset of hypogonadism were excluded. Sexual maturity rating, semen analysis, serum testosterone and FSH level were estimated in all patients at baseline and at 6 months duration of treatment. Testicular biopsy, Karyotyping and MRI brain were performed in selected cases. Azoospermic patients having hypogonadotropic hypogonadism were treated with long-acting testosterones and gonadotropins.

OBSERVATION

The study subjects were infertile azoospermic males. On the basis of serum FSH and testosterone levels, they were classified into two groups. Group A (n=42) cases were hypergonadotropic hypogonadism or primary testicular failure; of these 32 were Klinefelter syndrome (XXY), 7 chronic orchitis and 3 empty scrotal syndrome including one case of anorchia. These patients also developed other systemic illnesses in addition to hypogonadism. Group B (n=8) hypogonadotropic hypogonadism or secondary testicular failure; of these 2 were Kallman syndrome and the rest were idiopathic. After testosterone replacement all patients were virilized and there was marked improvement in libido and androgenization.

CONCLUSION

The study brings out that primary testicular failure is more common than secondary testicular failure. Both pattern of hypogonadism should receive lifelong androgen replacement therapy; otherwise, they will be a basket of multiple systemic disorders. Presently testosterone undecanoate once in every three months is the agent of choice.

Lead, cadmium and nickel removal efficiency of white-rot fungus Phlebia brevispora

Widespread of heavy metals contamination has led to several environmental problems. Some biological methods to remove heavy metals from contaminated wastewater are being widely explored. In the present study, the efficiency of a white-rot fungus, Phlebia brevispora to remove different metals (Pb, Cd and Ni) has been evaluated. Atomic absorption spectroscopy of treated and untreated metal containing water revealed that all the metals were efficiently removed by the fungus. Among all the used metals, cadmium was the most toxic metal for fungal growth. Phlebia brevispora removed maximum Pb (97·5%) from 100 mmol l^-1 Pb solution, which was closely followed by Cd (91·6%) and Ni (72·7%). Scanning electron microscopic images revealed that the presence of metal altered the morphology and fine texture of fungal hyphae. However, the attachment of metal on mycelia surface was not observed during energy-dispersive X-ray analysis, which points towards the intracellular compartmentation of metals in vacuoles. Thus, the study demonstrated an application of P. brevispora for efficient removal of Pb, Cd and Ni from the metal contaminated water, which can further be applied for bioremediation of heavy metals present in the industrial effluent.

Extended Spectrum β-lactamase (ESBL) Producing Multi Drug Resistant (MDR) Urinary Pathogens in a Children Hospital from Nepal

Background Multidrug resistant in clinical bacterial isolates has increasingly been reported through out the world and is associated with high morbidity, mortality and increased health care costs. It is important to determine the status of multidrug resistance pattern to understand the current resistance trend so that appropriate antibiotics can be used in practice. Objective To determine the antibiotic resistant profile and prevalence of extended spectrum β-lactamase producing multidrug resistant strains in pediatric patients of Kanti Children's Hospital, Kathmandu, Nepal. Method Urine sample was cultured by standard microbiological techniques and bacterial isolates were identified using different biochemical tests. Antibiotic susceptibility testing was performed by Kirby Bauer disc diffusion method and extended spectrum β-lactamase detection was carried out using combined disc method as recommended by Clinical Laboratory Standard Institute guidelines. Result All together 65 different bacteria were isolated and subsequently identified. E. coli was the most common isolate with 46 (71%) isolates 63% of these isolates were multidrug resistant. Gram negative isolates were most resistant to nalidixic acid (81.97%) followed by ampicillin (69.35%) and co-trimoxazole (69.35%). The extended spectrum β-lactamase producing isolates were 43% among total isolates. Conclusion Higher rate of Extended Spectrum β-lactamase production among multidrug resistant isolates suggested routine extended spectrum β-lactamase testing in clinical isolates.

Anaesthetic Management of a Morbidly Obese Parturient for Elective Caesarean Section

Anaesthesia for an obese parturient poses a challenge to anaesthesiologists. Here we report a case of 27 years obese primigravidae at 40 weeks of gestation with gestational hypertension who underwent elective cesarean section under combined spinal epidural anaesthesia. Her intraoperative and postoperative periods were uneventful. 

Risk Factors and Outcome of Neonates Born through Meconium Stained Amniotic Fluid in a Tertiary Hospital of Nepal

Introduction: The incidence of meconium aspiration syndrome is still high in the developing world contributing significantly to the neonatal mortality. The study was aimed to know the risk factors contributing to meconium aspiration syndrome and neonatal outcome in a tertiary government hospital of the country.Materials and Methods: It was a hospital based cross sectional study done over a period of three months. All live newborns born through meconium stained liquor were enrolled and all the details regarding mother, neonate were recorded. Odd’s ratio and bivariate analysis was done to assess the risk factors for meconium aspiration syndrome.Result: Out of all the deliveries 14.6% were meconium stained amniotic fluid and meconium aspiration syndrome developed in 6.6% of the neonates. Low Apgar score and premature rupture of membranes was significantly associated with the risk of occurrence of meconium aspiration syndrome. Neonates who developed meconium aspiration syndrome had mortality of 11.3%.Conclusion: Perinatal asphyxia and premature rupture of membranes were significantly associated with the development of meconium aspiration syndrome and neonates who developed meconium aspiration syndrome had high mortality.J Nepal Paediatr Soc 2015;35(1):44-48

Evaluation of intubating conditions in children after sevoflurane induction using propofol or rocuronium bromide--a randomised, prospective, double blind study

BACKGROUND

The use of sevoflurane without muscle relaxant for tracheal intubation has been widely investigated in children. Non-depolarizing neuromuscular blockers have long duration of action and do not provide rapid return of spontaneous ventilation. Use of suc-cinylcholine has been found to be associated with various side-effects especially in children. Therefore, we aim to evaluate the effect of propofol 1.5 mg/kg without muscle relaxant, on intubating conditions in children 2-8 yrs of age and we compare them with those achieved with rocuronium 0.6 mg/kg, at moderate sevoflurane concentration.

METHODS

Fifty children between 2-8 yrs, ASA I or II scheduled for elective surgery were randomly allocated to either Group P (propofol) or group R (rocuronium). After premedication with oral midazolam 0.5 mg/kg 30 min before surgery, anaesthesia was induced with 8% sevoflurane in oxygen. Intravenous fentanyl 1 µg/kg was administered after securing intravenous access and dial concentration of sevoflurane was reduced to 4%. At one minute with regards to time T₀, the patients received the drug which was either intravenous rocuronium 0.6 mg/kg or an equal volume of 0.9% saline (D) and at three minutes (two minutes after D₁), second drug (D₂) was given, which was either propofol 1.5 mg/kg or an equal volume of 0.9% saline according to the group allocated. At four minutes, laryngoscopy was done and intubation performed with appropriate sized uncuffed endotracheal tube. Incidence of acceptable and excellent intubating conditions, time to intubation and hemodynamic parameters were recorded.

RESULTS

Incidence of acceptable or excellent intubating conditions was similar in both groups (p = 1.00). The difference in time to intubation was statistically not significant (25.03 ± 6.05s in Group P and 24.38 ?5.58s in Group R, p = 0.694), at similar end-tidal concentration of sevoflurane (3.2 ± 0.20% in Group P and 3.1 ± 0.20% in Group R, p = 0.12).

CONCLUSION

Propofol (1.5 mg/kg) and rocuronium (0.6 mg/kg) produced similar intubating conditions in children induced with sevoflurane.

Anesthetic Management of a Parturient with Poliomyelitis Associated with Kyphoscoliosis

A 27-year-old primigravida with poliomyelitis associated with kyphoscoliosis underwent cesarean section under spinal anesthesia. Anesthesia poses a significant risk to a parturient with kyphoscoliosis and there is no single regimen that can be recommended for anesthetic management. Regional anesthesia is also challenging for anesthesiologist because the distortion of the spinous process and rotation of the vertebral column. The perioperative period was uneventful. Spinal anesthesia can be safely administered with less adverse effects in poliomyelitis patients with kyphoscoliosis. DOI: http://dx.doi.org/10.3126/njog.v9i1.11193 NJOG 2014 Jan-Jun; 2(1):67-70

Relationship between oral health status and oral health related quality of life in adults attending H.P Government Dental College, Shimla, Himachal Pradesh--India

OBJECTIVES

To describe Oral Health Related Quality of Life (OHRQoL) in adults attending the Outpatient Department (OPD) of Public health Dentistry, H.P Government Dental College, Shimla, and to assess the relationship between clinical measures of oral health status and oral health related quality of life.

METHODS

A cross sectional study was carried out for a period of three months on 351 subjects reporting to the OPD of Public health Dentistry, H.P Government Dental College, Shimla. Subjects were examined systemically for dental caries, periodontal disease using DMFT index and CPI index. OHRQoL was measured using the 14 - item Oral Health Impact Profile questionnaire (OHIP-14). Also the data on education, socio economic status and reasons for seeking dental care was collected.

RESULTS

There were 158 males and 193 females participating in the study. The mean age of study population was 35.7 ± 9.33. The mean total OHP-14 score was 9.5 ± 9.4; 35.6% of the subjects reported one or more OHIP problems 'fairly often or very often'. When the prevalence of impacts fairly /very often was modeled using logistic regression, presence of decayed teeth, presence of periodontal disease (CPI score >2) and number of missing teeth remained significantly associated with OHRQoL after adjusting for gender and episodic dental care.

CONCLUSION

OHIP-14 scores were significantly associated with the clinical oral health status indicators, independently of gender and socio economic inequalities in oral health.

Dental caries prevalence and treatment needs among 12- and 15- Year old schoolchildren in Shimla city, Himachal Pradesh, India

CONTEXT

Dental caries is one of the commonest oral diseases in children. Despite this fact, not many studies have been done on this issue among school children in Shimla.

AIM

To assess the prevalence of dental caries and treatment needs among schoolchildren aged 12 years and 15 years in Shimla city, Himachal Pradesh, India. With this study we also aimed to establish reliable baseline data.

DESIGN

Cross-sectional study.

MATERIALS AND MATERIALS

This study was conducted among 12 - and 15 - year old schoolchildren in Shimla city, Himachal Pradesh-India. A sample of 1011 schoolchildren was selected by a two-stage cluster sampling method. Clinical recording of dental caries, was done according to WHO diagnostic criteria (1997).

STATISTICAL ANALYSIS

The statistical tests used were the t- test, and the Chi-square test.

RESULTS

The prevalence of dental caries was 32.6% and 42.2% at 12 years and 15 years respectively. At 12 years of age, the mean Decayed Missing Filled Teeth was 0.62 ± 1.42 and it was 1.06 ± 2.93 at 15 years of age. Females had higher level of caries than males at both the ages. Dental caries was higher in children from government schools as compared to those from private schools. The 'decayed' component was the biggest contributor to the DMFT index. The highest treatment need at both ages was one surface restoration.

CONCLUSION

The caries experience of 12- and 15- year-old children was low compared to WHO - 'recommended' values. Effective oral health promotion strategies need to be implemented to further improve the dental health of school children in Shimla city.

Knowledge and attitudes about HIV/AIDS of students in H.P. Government Dental College and Hospital, Shimla, India

The purpose of this cross-sectional survey was to assess the knowledge and attitudes towards patients with HIV/AIDS among dental students in H.P. Government Dental College, Shimla, India. In November 2011, a survey was conducted of all the dental students of the college using a forty-five-item, self-administered questionnaire. The total mean knowledge score was 68.3 percent (good knowledge). The mean knowledge score was statistically higher in the clinical group than in the preclinical group. A majority of the students were aware of the association between HIV and oral candidiasis (89.1 percent), major aphthous (83.2 percent), and Kaposi's sarcoma (68.9 percent). Only 4.9 percent had professional attitudes about treating patients with HIV/AIDS. Male students had significantly fewer negative attitudes and higher positive attitudes than female students. The overall attitude score was significantly higher in the clinical group than in the preclinical group. Although a majority of the students had good knowledge, there were some inadequacies in their knowledge; those were more frequently seen in the preclinical students. It is important that dental students, as future dentists, develop not only the necessary practical skills but also knowledge and attitudes that will prepare them to treat patients with HIV/AIDS.

Prevalence of malocclusion and orthodontic treatment needs among 16 and 17 year-old school-going children in Shimla city, Himachal Pradesh

BACKGROUND

Many studies have been conducted in India to know the prevalence of malocclusion and the orthodontic treatment needs using dental aesthetic index (DAI), but no study so far has been conducted in Shimla city, Himachal Pradesh.

OBJECTIVE

To know the prevalence of malocclusion and orthodontic treatment needs among 16- and 17 year-old school-going children in Shimla city, Himachal Pradesh.

MATERIALS AND METHODS

The study was carried out on 622 (365 boys and 257 girls) school children, aged 16 and 17 years, from February 2009 to May 2009. Type III examination was conducted and the assessment of malocclusion was done according to the DAI.

RESULTS

20.28% of the male and 24.52% of the female students in the sample were affected with malocclusion. The mean DAI scores of the male and female children were 22.26 and 21.79, respectively. Distribution of the four DAI grades was as follows: DAI-I (no abnormality or minor malocclusion) 79.58%, DAI-II (definite malocclusion) 16.39%, DAI-III (severe malocclusion) 3.69%, DAI-IV (very severe/handicapping malocclusion) 0.34%.

CONCLUSION

The present study shows that 20.42% of the children examined had malocclusion which required treatment.

Malnutrition in children aged 6-59 months in Mugu district

BACKGROUND

Malnutrition is one of the leading causes of child morbidity and mortality. The severity of hunger in mountain and hill districts of Mid- and Far-Western Development Regions is a serious concern. Mugu, is one of the most remote and least developed districts of Nepal, periodically facing food insufficiency. This study was carried out to evaluate the malnutrition status of the most vulnerable group of children (6-59 months age group) in Mugu district.

METHODS

This study conducted in Mugu district was prospective and observational. Nutritional status of children aged 6-59 months were assessed by measuring mid-upper arm circumference by using MUAC tape and data was collected by interviewing caretakers. The data were analyzed and compared to the national figure.

RESULTS

Altogether 198 children aged 6-59 months were recruited for this study. Among them 49% were boys and 51% were girls. According to MUAC criteria, 1% of children had suffered from Severe Acute Malnutrition (SAM), 17% had Moderate Acute Malnutrition (MAM) and 82% had adequate nutritional status.

CONCLUSIONS

The prevalence of Acute Malnutrition is high in Mugu district. The important factors, among numerous others are food scarcity, poor hygiene and environmental practices, lack of care of the mother towards her child due to priority given to work and lack of knowledge about proper child feeding/care.

Integrated modelling of sewer system and wastewater treatment plant for investigating the impacts of chemical dosing in sewers

Chemicals are often dosed to control the production and accumulation of hydrogen sulfide in sewers. The biological and/or chemical actions of these chemicals have profound impacts on the composition of wastewater entering a WWTP, thereby affecting its performance. In this paper, an integrated modelling methodology for simultaneously investigating the effects of dosing of chemicals in sewer network and N and P removal at the downstream WWTP is reported. The sewer system is modelled using a sewer model (SeweX), and the WWTP is modelled using ASM2d model with some modifications. The importance of integrated modelling in sewer management is also demonstrated.

Towards a benchmarking tool for minimizing wastewater utility greenhouse gas footprints

A benchmark simulation model, which includes a wastewater treatment plant (WWTP)-wide model and a rising main sewer model, is proposed for testing mitigation strategies to reduce the system's greenhouse gas (GHG) emissions. The sewer model was run to predict methane emissions, and its output was used as the WWTP model input. An activated sludge model for GHG (ASMG) was used to describe nitrous oxide (N(2)O) generation and release in activated sludge process. N(2)O production through both heterotrophic and autotrophic pathways was included. Other GHG emissions were estimated using empirical relationships. Different scenarios were evaluated comparing GHG emissions, effluent quality and energy consumption. Aeration control played a clear role in N(2)O emissions, through concentrations and distributions of dissolved oxygen (DO) along the length of the bioreactor. The average value of N(2)O emission under dynamic influent cannot be simulated by a steady-state model subjected to a similar influent quality, stressing the importance of dynamic simulation and control. As the GHG models have yet to be validated, these results carry a degree of uncertainty; however, they fulfilled the objective of this study, i.e. to demonstrate the potential of a dynamic system-wide modelling and benchmarking approach for balancing water quality, operational costs and GHG emissions.

Lingual thyroid in children

Lingual thyroid is a rare embryological anomaly and originates from failure of the thyroid gland to descend from the foramen caecum to its normal eutopic pre-laryngeal site. The ectopic gland located at the base of the tongue is often asymptomatic but may cause local symptoms such as dysphagia, dysphonia with stomatolalia, upper airway obstruction and haemorrhage, often with hypothyroidism. One case is presented, in a 5 year-old girl patient, who complained of sensation of a foreign body and progressive dysphagia and dyspnoea caused by ectopic lingual thyroid. The diagnosis of lingual thyroid is usually made clinically and radionuclide scanning is used to confirm the diagnosis. In this case report, presentation, diagnosis and management of this condition is highlighted.

Multipoint incremental motor unit number estimation as an outcome measure in ALS

BACKGROUND

Improved outcome measures are necessary to reduce sample size and increase power in amyotrophic lateral sclerosis (ALS) clinical trials. Motor unit number estimation (MUNE) is a potentially attractive tool. MUNE methods previously employed in multicenter trials exhibited excessive variability and were prone to artifact.

OBJECTIVE

To evaluate a modification of standard incremental MUNE in a multicenter natural history study of subjects with ALS.

METHODS

Fifty healthy subjects were evaluated twice and 71 subjects with ALS were studied repeatedly for up to 500 days. Side and nerve studied was based on clinical examination findings. Nerves were stimulated at 3 specified locations and 3 increments were obtained at each location. Average single motor unit action potential (SMUP) amplitude was calculated by adding the amplitude of the third increment at each location and dividing by 9; SMUP was divided into maximum CMAP amplitude to determine the MUNE.

RESULTS

Test-retest variability was 9% in normal subjects. Average MUNE for normal subjects was 225 (±87), and was 41.9 (±39) among subjects with ALS at baseline. Subjects with ALS showed clear decrements over time, with an overage rate of decline of approximately 9% per month. SMUP amplitude increased with time in a fashion consistent with the known pathophysiology of ALS.

CONCLUSION

Multipoint incremental MUNE has a number of attributes that make it attractive as an outcome measure in ALS and other diseases characterized by motor unit loss. It can be rapidly performed on any EMG machine and has repeatability and rates of decline that favorably compare to other previously described methods.

Treatment of pseudo Class III malocclusion by modified Hawleys appliance with inverted labial bow

Pseudo Class III malocclusion is characterized by an anterior crossbite with functional forward mandibular displacement. Various appliances have been devised for early treatment of a pseudo Class III. The aim of this article is to highlight the method of construction and use a simple removable appliance termed as "Modified Hawleys appliance with inverted labial bow" to treat psuedo class III malocclusion in the mixed dentition period. It also emphasizes the importance of differentiating between true Class III and pseudo Class III. This appliance in this type of malocclusion enabled the correction of a dental malocclusion in a few months and therapeutic stability of a mesially positioned mandible encouraging favorable skeletal growth.

Dental prosthetic status, prosthetic needs in relation to socioeconomic status of the state government employees in Shimla city (Himachal Pradesh) - A cross sectional study

Objective:

To know the dental prosthetic status, prosthetic needs in relation to socioeconomic status (SES) of the state government employees in Shimla city, Himachal Pradesh.

Materials and Methods:

The study was carried on 1008 (705 males and 303 females) state government employees in Shimla city between February 25, 2009 and April 10, 2009. Type III examination was conducted and the prosthetic status and prosthetic needs were recorded on W.H.O. format 1997. Modified Kuppuswamy scale, with readjustment of the per capita income to suit the present levels, was used for SES classification.

Results:

10.3% of the subjects in the study had prosthesis of some kind. The prosthetic status was better in the upper middle and upper SES category as compared with the other categories and the findings were statistically significant. Prosthetic need in the study population was 33.2%, which was maximum for the subjects in the lower SES category and minimum for the higher SES category. Awareness on the provision of reimbursement for dental care was highest among the upper class and negligible in the lower SES category.

Conclusions:

Present study shows a direct relationship between SES and percentage of the subjects having prosthesis of some kind. SES shows an inverse relationship with prosthetic need and awareness on the provision of reimbursement of dental care.

Impact of nitrate addition on biofilm properties and activities in rising main sewers

Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L(-1) for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.

Clinical and electromyographic deep tendon reflexes in polyneuropathy: diagnostic value and prevalence*

BACKGROUND

Evidence is accumulating that patients with polyneuropathy may present with normal clinical deep tendon reflexes (C-DTR). There are few studies that assessed the diagnostic utility of electromyographically recorded DTR (Er-DTR) in patients with polyneuropathy.

OBJECTIVES

The objectives of this study were twofold: (i) to evaluate the prevalence of preserved C-DTR in polyneuropathy; (ii) diagnostic value of Er-DTR latency measurement in patients with polyneuropathy.

METHODS

We prospectively studied 38 controls and 185 patients with polyneuropathy. All subjects had evaluation of C-DTR, Er-DTR obtained from right biceps brachii (BR), right patellar (PR) and bilateral ankle reflexes (AR).

RESULTS

Of these 185 patients, 118 (63.8%) had chronic axonal neuropathy (CAN), 49 (26.5%) demyelinating polyradiculoneuropathy (DPN) and 18 (9.7%) small fiber neuropathy (SFN). The C-DTR were normal in 65 patients whereas 39 of these 65 (60%) patients had abnormalities of Er-DTR at one or more sites. Er-DTR latencies in patients with polyneuropathies were prolonged at all sites compared with controls (P < 0.01). Among patients with various types of polyneuropathies the Er-DTR, mean latencies at all the sites and latency indicative of demyelination (>150% of the normal mean) were higher in patients with DPN than that of CAN or SFN (P < 0.01).

CONCLUSIONS

We conclude that C-DTR are preserved in 35.1% of the patients with polyneuropathies and Er-DTR should be performed in such patients in order to provide electrophysiological evidence of a polyneuropathy. Er-DTR are useful in distinguishing axonal from demyelinating disorders of peripheral nerve, and detection of subclinical involvement of large fibers in SFN.

Failure of subarachnoid block in caesarean section

Subarachnoid block is the most convenient and safe anaesthesia during caesarean section. But there are incidences where subarachnoid block does not work and other methods of anaesthesia have to be employed. This study was done in 2039 female patients who underwent caesarean Section at Paropakar Maternity and Women's Hospital, Thapathali, Kathmandu Nepal from 1st October 2005 to end of September 2006 to find the rate of failure of subarachnoid block in Caesarean Section and look for the causes of failure. Patients of age 17 years to 43 years (mean age 25.40 years) and ASA I and II were included in the study. Spinal needle (Sprotte) of 26 Gauze with Quincke's bevel was used. Solution injected was 2.20 ml of 0.5% hyperbaric Bupivacaine. Of the total 2039 patients who received subarachnoid block with the above mentioned methods, 6.0% (n=123) needed further anesthetic agents. Conversion to general anesthesia was needed in 87 (4.3%) patients. Rest 1.8% (n=36) could be operated with further administration of intravenous agents (Ketamine, Diazepam and/or Pentazocine) only.

Comparative study of epidural administration of 10 ml of 0.1% bupivacaine with 2 mg butorphanol and 10 ml of 0.25% plain bupivacaine for analgesia during labor

Analgesia during labor provided by two epidural drug regimens was compared in a double blind, randomized, prospective study. Group A (n = 12) received 10 ml bolus doses of 0.1% bupivacaine with butorphanol 2 mg while Group B (n = 8) received 10 ml of 0.25% plain bupivacaine. The objectives of this study was to compare, between the quality of an epidural labor analgesia using initial loading dose of 0.1% bupivacaine and 2 mg butorphanol with a initial loading dose of 0.25% bupivacaine. In Group A, incidence of motor block was 8.3% and that of prolong 2nd stage of labor was 16.7%, both were decreased in comparison with Group B, although they were not statistically significant. Hemodynamic variables were stable and no adverse neonatal and maternal outcome was observed in both groups. Addition of butorphanol to bupivacaine may be safe alternative to reduce motor block and decrease prolong 2nd stage for epidural labor analgesia.

Effect of farmyard manure application on boron adsorption-desorption characteristics of some soils

Boron (B) availability to crop plants depends on soil properties as well as management practices like liming, fertilization and use of organic manures. To assess the effect of farmyard manure (FYM) application on availability of added B, adsorption-desorption of B was investigated in five different soils receiving varying doses of FYM (0, 5 and 10 g FYM kg(-1) soil). Two surfaces Freundlich model was found best to account for B adsorption-desorption data of all soils. Application of FYM increased B adsorption capacities pertaining to low (K1) and high (K2) concentration ranges in all soils, except Soil C (Alfisol) having a pH of 9.8, in which the higher rate of FYM decreased the value of K2. Application of FYM did not change B desorption capacities of soils corresponding to low B concentration range (K(1)(1)) significantly, however, it increased B desorption capacity pertaining to high B concentration (K(1)(2)) in all soils, except Soils C (Alfisol) and E (Entisol) having pH of 9.8 and 5.1, respectively. Application of FYM increased the desorption slope factor applicable to low concentration range (1/n(1)(1)) in Soil A (Inceptisol), but decreased it in Soil E (Entisol). The 1/n(1)(2) (desorption slope factor applicable to high concentration range) decreased with FYM application in all soils except Soil E (Entisol), where it was increased. Boron desorption index (slope(ads)/slope(des)) decreased with FYM application in low B concentration range, but increased in high concentration range for all soils except soil E (Entisol, pH 5.1), in which a reverse trend was observed. Application of FYM increased the retention of added B in soils and may help reducing the leaching losses.

Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage

An integrated anaerobic-aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC=100 mg/L and sulphate=500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77-85% of TOC at HRT of 3 h and produce 70-90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3- -N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.

High-rate wastewater treatment by aerobic upflow sludge blanket reactor: system performance and characteristics

A laboratory study was conducted to investigate the characteristics of an aerobic upflow sludge blanket reactor (AUSB) treating synthetic wastewater at a high organic loading. The response of the system was evaluated at different operating conditions, such as pressurization, extent of flow recirculation, and hydraulic retention time. Aeration shear to the biomass in the reactor was totally eliminated by employing oxygenation under pressurization in an external chamber. As a result, the biomass concentration in the reactor could be maintained at 7-10 g VSS l(-1). The AUSB system was able to handle efficiently a volumetric loading of as high as 3.8 kg TOC m(-3) d(-1), which was possibly due to high reactor biomass level and higher bioactivity as indicated by higher sludge specific oxygen uptake rates. However, the treatment capacity of the AUSB was somewhat limited by the substrate and oxygen transport in the sludge bed due to low mixing intensity. The effluent TOC of the AUSB system was relatively higher due to its operation at a high organic loading. The AUSB system performed well under a short term loading shock, and the bacterial activity in the oxygenation chamber was demonstrated to contribute to its improved substrate removal capacity under the shock loading.

Hydrogen-based tubular catalytic membrane for removing nitrate from groundwater

A porous tubular ceramic membrane coated with palladium-cupper (Pd-Cu) catalyst on its surface was prepared and evaluated for catalytic reduction of nitrate from groundwater. Nitrate reduction activity and selectivity with the catalytic membrane were compared with Pd-Cu/Al2O3 catalyst particles. The catalytic membrane reactor exhibited a better selectivity by enabling an effective control of hydrogen gas, thus minimizing ammonium production. No leaching of palladium and copper into aqueous phase was observed, thereby indicating a high chemical stability of the metallic ions on the carrier support. This was also evidenced by the X-ray photoelectron spectroscopy (XPS) profiles of fresh and used catalysts, which showed no significant difference in surface compositions. Due to its higher selectivity in nitrate reduction and better flexibility in terms of operating conditions, the tubular catalytic ceramic membrane could be useful in removing nitrate from groundwater.

High rate treatment by aerobic upflow sludge blanket (AUSB) with external oxygenation

A 3-year study was conducted using an aerobic upflow sludge blanket (AUSB) reactor to achieve high-rate biological treatment through maintenance of a high biomass concentration (7-10 g VSS/L) together with a high oxygen flux. The AUSB reactor was not aerated directly; instead, oxygenation was provided in an external chamber with flow recirculation. The oxygenation was provided at four different pressurizations: 0, 15, 20 and 25 psig. The AUSB reactor was also pressurized to avoid the flotation of biomass. The flow recirculation rate was varied from 400% to 1,500% in order to ensure adequate oxygen supply. It was found that the AUSB system was able to handle a volumetric loading of as high as 10 kg COD/m3-day with a removal efficiency of 92%. Despite a high upflow velocity through AUSB, the effluent suspended solid concentration was mostly below 60 mg/L. The active fraction of biomass in the AUSB sludge was about 3 times higher than that of the regular activated sludge. This was indicated by a very high specific oxygen uptake rate (SOUR), up to 180-250 mg O2/g VSS-hr. The sludge yield in the entire system was only 0.09 to 0.13 g VSS/g COD removed. This was mainly caused by additional auto-oxidation of biosolids in the oxygenation chamber due to flow recirculation.

Early diagnosis of carpal tunnel syndrome: comparison of digit 1 with wrist and distoproximal ratio

Our objective in this study was to compare the sensitivity and specificity of the median sensory nerve conduction velocity (SNCV) from digit 1 to wrist with those of the distoproximal (D/P) ratio of the median SNCV from palm to digit 3/palm to wrist in the diagnosis of mild carpal tunnel syndrome (CTS) by using a receiver operating characteristic (ROC) curve. To achieve this objective, we studied prospectively (January 1997-October 1998) 370 patients referred for CTS. One hundred forty-two patients (38.4%) with moderate to severe CTS and 15 patients (4.1%) with multiple (> or = 3) compressive neuropathies in upper limbs with subclinical peripheral neuropathy were excluded. The remaining 213 patients (302 hands with mild CTS; 167 women; mean age, 50 y +/- 12 y) and 38 controls (71 hands; 25 women; mean age, 47 y +/- 13 y) had median and ulnar nerve conduction studies. ROC curves were constructed for median SNCV digit 1 to wrist and median SNCV D/P ratio from the patients' and controls' data. The median SNCV at < or = 45.9 m/s, corresponding to an optimal cutoff point on ROC curve, discriminated 89.5% of mild CTS from controls with specificity of 98.6%. The median D/P ratio at > or = 1.12, corresponding to an optimal cutoff point on ROC curve, discriminated 67.2% of mild CTS from controls with specificity of 97.2%. Of the 10.3% (31/302) of hands in which digit 1 to wrist was within normal limits at the selected optimal cutoff value (< or = 45.9 ms), 7% (21/302) had an abnormal D/P ratio (> or = 1.12), and 3.3% (10/302) had a normal electrophysiologic examination. The likelihood ratio (true-positive ratio to false-positive ratio, assessing the discriminative power of a test) of the median SNCV digit 1 to wrist, at an optimal point on ROC curve (63.9), was higher than that of the median SNCV D/P ratio (23.9, chi2 = 36.9, P < .001). These findings suggest that the median SNCV digit 1 to wrist is more sensitive than the median SNCV D/P ratio in the diagnosis of mild CTS.

Anaesthetic considerations of temporomandibular joint ankylosis with obstructive sleep apnoea: a case report

The peroperative management of a 4 1/2 yr old child having bilateral recurrent temporomandibular joint (TMJ) ankylosis and obstructive sleep apnoea (OSA) is presented here. From the anaesthesiologist's point of view, the patient demands special considerations as regards difficulty in intubation, high sensitivity to all central depressant drugs, awake extubation, and post-operative maintenance of a clear airway. It is to be concluded that these conditions call for strict adherence to the basic principles of airway management and close observation extending into the post-operative period.

One and a half centuries of demographic transition in Nepal

This paper examines the past and prospective demographic transition in Nepal. Sparse data from the pre-1961 censuses suggest that mortality decline began during 1930s and allow rough estimates of fertility and mortality levels prior to 1961. Fertility decline began sometime between 1961 and early 1980s, with the total fertility rate declining from about 6 to 5 children per woman by early 1990s. The four scenarios of future fertility decline and population growth presented in the paper help draw several conclusions. A continuation of the recent slow pace of fertility decline would result in a total population of slightly over 100 million by the end of the next century (Scenario I). More rapid decline, similar to the median experience of Asian countries, would reduce this growth to below 60 million (Scenario III). Still more rapid decline, close to the limit of what has been observed in countries that have experienced the most rapid declines, could reduce the growth to 40 million (Scenario IV). It is possible, if not at present particularly plausible, that very rapid decline might be achieved by a combination of smaller family sizes and rising age of childbearing. An approach to reaching zero population growth rapidly--and anything less than a doubling of current population--may be ruled out with a high degree of certainty (Scenario II and IV). A doubling of population to 40 million is the least possible growth that can be expected. At the current rate of fertility decline, population will increase to 100 million during this century. If a smaller population in this range is considered to be in the national interest, it is as important to work for more rapid fertility decline as it is to work for accommodation of a much larger population.

The spectrum of chronic inflammatory demyelinating polyneuropathy

Research criteria for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) were proposed by an Ad Hoc Subcommittee of the American Academy of Neurology (AAN) in 1991, and since then these criteria have been widely used in clinical studies. We have been impressed by the frequent finding of electrophysiological changes of a demyelinating neuropathy in patients whose clinical presentation does not conform to the usually accepted clinical phenotype of CIDP. To determine the clinical spectrum of CIDP, we conducted a retrospective review of patients of the peripheral electrophysiology laboratory of the University of Miami-Jackson Memorial Medical Center. Diagnostic criteria for acquired demyelination of an individual nerve were adapted from the AAN research criteria for the diagnosis of CIDP (1991). Patients were accepted for inclusion when such evidence was demonstrated in at least one motor nerve or at least two sensory nerves. We then reviewed the clinical phenotype and the underlying etiology of the neuropathy in these cases. Eighty-seven patients, 63 male and 24 female, age of onset 4-84 (mean 49.3) years, met these inclusion criteria. Forty-seven patients (54%) had distinct features outside the usual clinical presentation of CIDP. Of these, 15 (17%) had predominantly distal features, 13 (15%) had exclusively sensory polyneuropathy; seven (8%) had markedly asymmetric disease, seven (8%) had associated CNS demyelination, four (5%) had predominant cranial nerve involvement, and one (1%) had only the restless legs syndrome. An associated medical condition that may have been responsible for the acquired demyelinating neuropathy was present in 60% of the patients. We conclude that spectrum of CIDP is broader than would be indicated by the strict application of the AAN research criteria, and that many of the cases meeting more liberal criteria frequently respond to immunosuppressive therapy.

Sympathetic skin response and heart rate variability in patients with Huntington disease

OBJECTIVE

To examine the autonomic nervous system functions in patients with Huntington disease.

BACKGROUND

Although patients with Huntington disease frequently experience vegetative symptoms, it is not clear if there is dysfunction of the autonomic nervous system.

METHODS

Sympathetic skin response (SSR) latency and amplitude from both palms and soles and R-R (heart rate) interval variation (RRIV) at rest and during the Valsalva maneuver were examined in 22 patients and 21 age-matched controls. Unified Huntington's Disease Rating Scale scores were determined in all the patients.

RESULTS

Our data are reported as means +/- SEMs. The SSR latencies in patients (mean palm latency, 1835.8+/-110.7 milliseconds; mean sole latency, 2625.3+/-226.9 milliseconds) were prolonged compared with controls (mean palm latency, 1359.5+/-28 milliseconds [P<.01]); mean sole latency, 2038.1+/-44.9 milliseconds [P<.01]) and amplitudes in patients (mean amplitude, 1063.1+/-237.7 microV) were smaller compared with controls (mean amplitude, 1846.3+/-251.2 microV [P<.05]). The RRIV in patients both at rest (mean RRIV in patients, 3.7%+/-0.4% vs. controls, 9.7%+/-0.6% [P<.01]) and during the Valsalva maneuver (mean RRIV in patients, 6.3%+/-1.6% vs. controls, 14.5%+/-1.2% [P<.01]) was lower compared with controls. Furthermore, the prolonged SSR latencies, smaller amplitudes, and lower RRIV in patients compared with controls closely correlated with the various components of the Unified Huntington's Disease Rating Scale scores (total behavior score and SSR latency, R = 0.6 [P<.01]; total behavior score and SSR amplitude, R = -0.5 [P<.05]; total behavior score and RRIV, R = -0.4 [P<.05]; verbal fluency and SSR latency, R = -0.5 [P<.05]; verbal fluency and SSR amplitude, R = 0.5 [P<.05], verbal fluency and RRIV, R = 0.5 [P<.05]; total functional capacity and SSR latency, R = -0.6 [P<.01]; total functional capacity and SSR amplitude, R = 0.5 [P<.05]).

CONCLUSION

These results suggest that there is autonomic nervous system dysfunction in patients with Huntington disease.

Myoblast implantation in Duchenne muscular dystrophy: the San Francisco study

We evaluated myoblast implantation in 10 boys with Duchenne muscular dystrophy (DMD) and absent dystrophin (age 5-10 years) who were implanted with 100 million myoblasts in the anterior tibial muscle of one leg and placebo in the other. Cyclosporine (5 mg/kg/day) was administered for 7 months. Pre- and postimplantation (after 1 and 6 months) muscle biopsies were analyzed. Force generation (tetanic tension and maximum voluntary contraction) was measured monthly in a double-blind design. There was increased force generation in both legs of all boys, probably due to cyclosporine. Using the polymerase chain reaction, evidence of myoblast survival and dystrophin mRNA expression was obtained in 3 patients after 1 month and in 1 patient after 6 months. These studies suggest a salutary effect of cyclosporine upon muscular force generation in Duchenne muscular dystrophy; however, myoblast implantation was not effective in replacing clinically significant amounts of dystrophin in DMD muscle.

Electrical and mechanical properties of skeletal muscle underlying increased fatigue in patients with amyotrophic lateral sclerosis

To investigate the mechanical efficiency of surviving motor units of anterior tibial muscle in patients with amyotrophic lateral sclerosis (ALS), we studied motor unit action potentials, muscle force, and muscle fatigability in patients with ALS and controls using 25 min of low to moderate intensity voluntary isometric exercise. During exercise, tetanic force (TF) and maximum voluntary contraction declined more in patients than in controls. The mean motor unit action potential duration, amplitude, and polyphasia were increased in patients compared to controls but did not change during 9 months of disease progression. The enlarged motor units in patients were negatively correlated to the muscle force and positively correlated to muscle fatigability. Furthermore, after a mean follow-up period of 9 months, the decline in force-generating capacity of the anterior tibial muscle in patients (twitch tension by 37.5 +/- 11.2%, TF by 30.6 +/- 7.4%) was greater than the decline in the amplitude of the compound muscle action potential (21.1 +/- 8.8%, P < 0.05), suggesting a relative dissociation between electrical and mechanical properties. In conclusion, the enlarged motor units in patients with ALS are mechanically less efficient and fatigue relatively more than in healthy muscles, possibly due to an abnormality that is primarily distal to the muscle membrane.

Occipital lobe tumor presenting as migraine with typical aura

We report the case of a 60-year-old woman in whom migraine with typical aura heralded the presence of an occipital lobe tumor. Her headache was characterized by recurrent episodes of visual aura confined to the left visual field followed by right hemicranial throbbing headaches accompanied by nausea, photophobia, and phonophobia. Interictal neurologic and ophthalmologic examinations were negative, as was an unenhanced brain CT scan. The headaches increased in frequency over 4 months despite a number of medications known to prevent attacks of migraine. A low-grade right occipital lobe tumor was eventually discovered on MR scan. This case illustrates that headache fulfilling the International Headache Society (IHS) criteria for migraine with typical aura can occur in association with an occipital lobe tumor.

Evidence of an abnormal intramuscular component of fatigue in multiple sclerosis

The goals of this study were to investigate muscle fatigue in patients with multiple sclerosis (MS), and to determine the relationships between muscle fatigue, clinical status, and perceived fatigue. The fatigability of the anterior tibial muscle was quantitated in patients and controls during 9 min of intermittent stimulation (used to eliminate central sources of muscle fatigue). During exercise, the decline in tetanic force, phosphocreatine, and intracellular pH was greater in patients than in controls. The compound muscle action potential amplitude did not decrease during exercise, indicating that there was no failure of neuromuscular transmission during fatigue. Thus, the excessive fatigue in MS developed from sources beyond the muscle membrane. Following exercise, the recovery of tetanic force was delayed in patients (a pattern that suggests abnormal excitation-contraction coupling), whereas the recovery of metabolites was complete in both groups. Muscular fatigue was correlated with clinical disability but not with perceived fatigue. These results suggests that fatigue in MS has both central (perception, upper motor neuron dysfunction) and peripheral (impaired metabolism and excitation-contraction coupling) components.

Physiology of fatigue in amyotrophic lateral sclerosis

We investigated the mechanisms of muscle fatigue in ALS. In the muscles of ALS patients and healthy control subjects, we examined (1) fatigue using measurements of muscle force, (2) energy metabolism using phosphorus-31 magnetic resonance spectroscopy, and (3) activation using neurophysiologic measures and MRI. During 25 minutes of intermittent isometric exercise of the tibialis anterior muscle, both maximum voluntary and tetanic force declined more in patients than in controls, indicating greater fatigability in ALS. There was a similar decline of voluntary and tetanic force, suggesting that much of the fatigue was not central. Evoked compound muscle action potential amplitudes were preserved during exercise in both groups, indicating no failure of neuromuscular transmission; this result suggests that the source of fatigue was not at the neuromuscular junction or within the muscle membrane. In spite of greater fatigability, changes during exercise in energy metabolites and proton signal intensity tended to be less in ALS patients compared with controls, suggesting impaired muscular activation. We conclude that the greater muscle fatigue in ALS patients results from activation impairment, due in part to alterations distal to the muscle membrane.

Muscular fatigue in Duchenne muscular dystrophy

We used a 4-minute sustained maximum voluntary contraction to investigate fatigability of the anterior tibial muscle in eight healthy boys and 11 boys with Duchenne muscular dystrophy (DMD) (ages 5 to 10 years). Before exercise, the force generation of dystrophic muscle and the compound muscle action potential amplitude were lower and half-relaxation time of the tetanus was longer in patients than in controls. During exercise, the decline in tetanic force and potentiation in twitch tension were similar in both groups. However, during exercise, there was less decline in maximum voluntary contraction and less added force in DMD patients, suggesting that there was less central fatigue in patients than in controls. Thus, patients with DMD and controls have similar intramuscular fatigability and excitation-contraction coupling, and central activation in patients is functioning as well as or better than in healthy controls.

Effects of exercise on muscle activation and metabolism in multiple sclerosis

We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise, MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 +/- 0.22 in controls but to only 0.66 +/- 0.04 in MS (P < 0.01); likewise, pH was 6.75 +/- 0.04 in controls and unchanged (7.06 +/- 0.04) in MS (P < 0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophysiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane (excitation-contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS.

Postexercise phosphocreatine resynthesis is slowed in multiple sclerosis

To determine whether skeletal muscle oxidative metabolism is impaired in multiple sclerosis (MS), phosphorus magnetic resonance spectroscopy was used to measure the rate of intramuscular phosphocreatine (PCr) resynthesis following exercise in MS and controls. Thirteen MS patients underwent intermittent isometric tetanic contractions of the dorsiflexor muscles elicited by stimulation of the peroneal nerve. Eight healthy control subjects performed voluntary isometric exercise of the same muscles. During exercise, there were no differences between groups in the fall of either PCr or pH. However, the half-time (T1/2) of PCr recovery following exercise was significantly longer in MS (2.3 +/- 0.3 min) compared to controls (1.2 +/- 0.1 min, P < 0.02). These data provide evidence of slowed PCr resynthesis following exercise in MS, which indicates impaired oxidative capacity in the skeletal muscle of this group. This finding suggests that intramuscular changes consistent with deconditioning may be important in the altered muscle function of persons with MS.

Excessive muscular fatigue in the postpoliomyelitis syndrome

To investigate anterior tibial muscle fatigability and metabolism in postpoliomyelitis syndrome patients and controls, we performed measurements of force and relaxation time, as well as 31P magnetic resonance spectroscopy, during intermittent, low-intensity, isometric, voluntary exercise. Both maximum voluntary contraction and tetanic force declined significantly more during exercise and subsequently recovered less in patients compared with controls, indicating greater fatigue in patients. However, intracellular pH and phosphocreatine were not different in the two groups at rest or during exercise or recovery, suggesting that the greater fatigue of the patients was not due to an excessive change of metabolites. Moreover, the pre-exercise half-relaxation time of the tetanus was significantly prolonged in patients compared with controls, and the decline in tetanic force during exercise was linearly related to the half-relaxation time of tetanus, suggesting impaired calcium kinetics. Taken together, the findings of increased fatigability, delayed recovery, and prolonged half-relaxation time, without differences in metabolites, suggest that the fatigue in postpoliomyelitis syndrome may be due to impaired activation beyond the muscle membrane.

Quantitative MR relaxometry study of muscle composition and function in Duchenne muscular dystrophy

Magnetic resonance imaging and maps of T1 and T2 values were used to study muscle composition in Duchenne muscular dystrophy (DMD). The mean T2 of anterior tibial muscle was 27 msec in healthy control subjects and 43 msec with increased fatty infiltration in DMD patients. In stronger DMD patients, the distribution of muscle T2 values was narrow, centered at 27 msec as in the controls, with a nonoverlapping fat peak centered at 49 msec. In weaker DMD patients, the width of the muscle T2 peak increased and the peak shifted toward the fat peak. Mean muscle T1 decreased from 1.7 to 0.6 second with increasing fatty infiltration. These results show that quantitative T1 and T2 maps may be used to assess muscle status and monitor DMD progression.