Absolute stereochemistry of the spiroxins

The absolute configuration of spiroxin A has been determined by exciton-coupled circular dichroism (CD). Namely, the difference CD between spiroxin A – bis-methoxycinnamate, as well as that between spiroxin A – bis-retinoate, both exhibit negative exciton couplings between the acylated phenolic hydroxyl group chromophores. This establishes the absolute configuration as 2S,3R,4S,2'S,3'R,4'S.Key words: circular dichroism, exciton coupling, spiroxins, antitumor, antifungal.

New biotransformation products of nemadectins

Selected nemadectins (formerly LL-F28249 series) have been fed to a panel of microorganisms with the aim of generating new derivatives. In addition to products resulting from the oxidation of the terminal methyl group (C-29), a unique phosphorylated nemadectin was isolated. The phosphate group was determined to be at C-23 by HMBC between phosphorus and H-23. Milbemycin or nemadectin derivatives with natural substituents involving the 23-hydroxyl group were hitherto unknown.

Marijuana in the management of amyotrophic lateral sclerosis

Marijuana has been proposed as treatment for a widening spectrum of medical conditions. Marijuana is a substance with many properties that may be applicable to the management of amyotrophic lateral sclerosis (ALS). These include analgesia, muscle relaxation, bronchodilation, saliva reduction, appetite stimulation, and sleep induction. In addition, marijuana has now been shown to have strong antioxidative and neuroprotective effects, which may prolong neuronal cell survival. In areas where it is legal to do so, marijuana should be considered in the pharmacological management of ALS. Further investigation into the usefulness of marijuana in this setting is warranted.

Advances in the management of neuropathic pain

Much progress has been made in the assessment and management of neuropathic pain over the past 5 years. Assessment has improved with the Neuropathic Pain Scale, a new, easily administered, diagnostic tool. Mechanistically, recent studies indicate that peripheral neuropathic pain is generated through a focal inflammatory process rather than axonal destruction. This process also appears to involve mRNA regulation of fast sodium channels, which produce ectopic discharges and are presumably responsible for pain generation. In addition the entire neuraxis undergoes neuroplastic changes as a result of peripheral nerve injury. The available clinical trial data indicate that newer antiepileptic drugs (AEDs), most notably gabapentin, are better alternatives to older medications such as carbamazepine or phenytoin in the treatment of neuropathic pain. Gabapentin is at least as good with respect to actual pain relief as the antidepressants, including amitriptyline, but has a much better safety profile with minimal drug-drug interactions and side effects. Mexiletine is a reasonable alternative agent in patients who have not had a satisfactory response to, or cannot tolerate, the AEDs or antidepressants. Long-acting opioids should be considered in patients refractory to these adjunctive agents. With the advent of the topical lidocaine patch, the first drug with an FDA-approved indication for postherpetic neuralgia, a revolutionary new agent is now available for the treatment of neuropathic pain that does not have any systemic side effects.

Health-related quality of life in peripheral neuropathy

It is now possible for the clinician to use multidimensional measures to assess the quality of life of their patients. Some of the more widely used instruments to measure HRQOL are the Medical Outcomes Study Short Form 36, the Nottingham Health Profile, the Sickness Impact Profile, and the World Health Organization Quality of Life instrument. Potential uses of quality of life assessment tools include: (1) monitoring the health and social status of a given population, (2) evaluating health care policy, (3) conducting clinical trials, (4) assessing the effectiveness of rehabilitation services, (5) justifying the allocation of limited social and health care resources, and (6) tailoring management to the needs of the patient.

Immobilized artificial membrane chromatography with mass spectrometric detection: a rapid method for screening drug-membrane interactions

A high-performance liquid chromatography (HPLC)/electrospray ionization mass spectrometry method for measuring drug-membrane interactions was developed using immobilized artificial membrane (IAM) fast-screening mini-columns. The HPLC mobile phase consisted of phosphate-buffered saline (i.e., 5.0 mM phosphate buffer at pH 7.4, 1.35 mM KCl, and 68.5 mM NaCl) and acetonitrile. This method facilitated the measurement of IAM retention time of over ten compounds in one experiment, significantly reducing analysis time compared with the earlier IAM-HPLC method. The particular electrospray source used demonstrated the ability to tolerate the high salt-containing nonvolatile buffer used for retention time measurement.

Preserving function in Duchenne dystrophy with long-term pulse prednisone therapy

We report a case of a patient with Duchenne muscular dystrophy who was treated with intermittent pulse prednisone for severe asthma from age 3 to 17 yr and had remarkable preservation of skeletal muscle function. He had a maternal uncle with Duchenne muscular dystrophy who had the identical familial deletion mutation and died at age 19 of respiratory failure. Compared with his untreated uncle, our patient remains partially ambulatory at age 20. This case provides interesting, albeit anecdotal, evidence of considerable clinical benefit from pulse prednisone used on a much longer term basis than has been previously studied and promotes the need for further investigation on this type of therapy in Duchenne muscular dystrophy.

Magnetic resonance imaging of denervated muscle: comparison to electromyography

The purpose of the study is to further assess the usefulness of short TI (time to inversion) recovery (STIR) magnetic resonance imaging (MRI) in detecting denervation of skeletal muscle compared to needle electromyography (EMG). Ninety subjects with clinical evidence of peripheral nerve injury or radiculopathy underwent STIR MRI and EMG of the affected limb. In 74 (82%) of these subjects, a positive correlation was found between STIR MRI and EMG (P < 0.009). STIR MRI has a relative sensitivity of 84% and specificity of 100% for detecting denervation. A subset of 28 subjects underwent quantitative assessments of signal intensity ratio (SIR) from the STIR MRI. The rank order correlation coefficient between the SIR and abnormal spontaneous activity on EMG was 0.70 (P < 0.001). Increased signal intensity on STIR MRI corresponds closely with spontaneous activity on EMG in denervated muscle. Although less sensitive than EMG in detecting muscle denervation, STIR MRI may be a useful adjunctive diagnostic tool in this setting.

Relative and absolute configurations of ganefromycin alpha

The full structure of ganefromycin alpha has been determined. The relative configurations were determined from 3JH,H coupling constants and NOE data, while the absolute configurations in moleties A and B were determined separately by difference CD of their acylate derivatives, which showed typical exciton couplets. The configurations of the stereogenic centers in ganefromycin alpha are 8S, 9S, 11R, 12S, 13S, 21S, 22R, 23R, 24R, and 26S.

Pursed lips breathing improves ventilation in myotonic muscular dystrophy

OBJECTIVE

To determine the effects of pursed lips breathing on ventilation, chest wall mechanics, and abdominal muscle recruitment in myotonic muscular dystrophy (MMD).

DESIGN

Before-after trial.

SETTING

University hospital pulmonary function laboratory.

PARTICIPANTS

Eleven subjects with MMD and 13 normal controls.

INTERVENTION

Pursed lips breathing.

OUTCOME MEASURES

Electromyographic (EMG) activity of the transversus abdominis, external oblique, internal oblique, and rectus abdominis was recorded with simultaneous measures of gastric pressure, abdominal plethysmography, and oxygen saturation. Self-reported sensations of dyspnea, respiratory effort, and fatigue were recorded at the end of each trial.

RESULTS

Pursed lips breathing and deep breathing led to increased tidal volume, increased minute ventilation, increased oxygen saturation, reduced respiratory rate, and reduced endexpiratory lung volume. Dyspnea, respiratory effort, and fatigue increased slightly with pursed lips breathing. EMG activity of the transversus abdominis and internal oblique muscles increased in MMD only and was associated with an increase in gastric pressure.

CONCLUSIONS

Pursed lips breathing and deep breathing are effective and easily employed strategies that significantly improve tidal volume and oxygen saturation in subjects with MMD. Abdominal muscle recruitment does not explain the ventilatory improvements, but reduced end-expiratory lung volume may increase the elastic recoil of the chest wall. Further clinical studies are needed to ascertain if the ventilatory improvements with pursed lips breathing and deep breathing improve pulmonary outcomes in MMD.

Electrodiagnostic evaluation of traumatic nerve injuries

This article reviews the techniques of motor and sensory nerve conduction studies and needle electromyography methods, which are particularly useful for localizing nerve injuries in upper extremity and hand trauma. Included are details of methods for detecting and quantifying the degree of axon loss and for using this information to make treatment decisions and predict outcomes. The epidemiology and classification of traumatic peripheral nerve injuries, the effects of these injuries on nerve and muscle, and the means by which electrodiagnosis is used to help classify the injury are described. An overview of recovery mechanisms also is presented.

Absolute stereochemistry of the strevertenes

The CD exciton chirality method was applied to determine the absolute stereochemistry of the strevertenes, antifungal pentaene macrolides produced by Streptoverticillium sp. LL-30F848. The CD difference spectrum of strevertene A methyl ester 15-dimethylaminobenzoate showed a positive couplet between the dimethylaminobenzoate and the pentaene chromophores, and therefore established the 15R configuration. Thus, by considering the relative configurations of the remaining stereogenic centers as derived from X-ray crystallography and ROESY experiments, the absolute stereochemistry of the strevertenes is established as 2R, 3S, 5S, 7S, 11R, 13R, 14R, 15R, 26S and 27R.

Expanding the role of hospice care in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive, ultimately fatal, motor neuron disease that poses a myriad of clinical and end-of-life problems. The needs of advanced ALS patients are well suited to the interdisciplinary, multi-modality setting of hospice, where comprehensive palliative strategies may ease suffering and allow the patient to die with dignity in the home. Unfortunately, hospice services are far underutilized in this setting. There is a great need to increase awareness of both patients and clinicians regarding the effectiveness of hospice in the care of advanced ALS patients.

Neuropathic pain in Charcot-Marie-Tooth disease

OBJECTIVES

To determine the frequency and extent to which subjects with Charcot-Marie-Tooth (CMT) disease report pain and to compare qualities of pain in CMT to other painful neuropathic conditions.

STUDY DESIGN

Descriptive, nonexperimental survey, using a previously validated measurement tool, the Neuropathic Pain Scale (NPS).

PARTICIPANTS

Participants were recruited from the membership roster of a worldwide CMT support organization.

MAIN OUTCOME MEASURES

NPS pain descriptors reported in CMT were compared with those reported by subjects with postherpetic neuralgia (PHN), complex regional pain syndrome, type 1 (CRPS-1), also known as reflex sympathetic dystrophy, diabetic neuropathy (DN), and peripheral nerve injury (PNI).

RESULTS

Of 617 CMT subjects (40% response rate), 440 (71%) reported pain. with the most severe pain sites noted as low back (70%), knees (53%), ankles (50%), toes (46%), and feet (44%). Of this group, 171 (39%) reported interruption of activities of daily living by pain; 168 (38%) used non-narcotic pain medication and 113 (23%) used narcotics and/or benzodiazepines for pain. The use of pain description was similar for CMT, PHN, CRPS-1, DN, and PNI in terms of intensity and the descriptors hot, dull, and deep.

CONCLUSIONS

Neuropathic pain is a significant problem for many people with CMT. The frequency and intensity of pain reported in CMT is comparable in many ways to PHN, CRPS-1, DN. and PNI. Further studies are needed to examine possible pain generators and pharmacologic and rehabilitative modalities to treat pain in CMT.

Hongoquercins A and B, new sesquiterpenoid antibiotics: isolation, structure elucidation, and antibacterial activity

Two new sesquiterpenoid antibiotics, hongoquercins A and B, were isolated from the extracts of an unidentified fungus. The structures of both metabolites were determined by spectroscopic analysis. They are related to a class of compounds commonly found in brown algae and dictyoceratid sponges. Hongoquercin A exhibited moderate activity against gram-positive bacteria.

Isolated superior gluteal nerve injury: two case reports

Isolated superior gluteal nerve injury has been infrequently described in the literature, mainly from injections or hip surgery. Its course through the greater sciatic foramen renders it at risk in pelvic or hip trauma. We report 2 cases of electromyographically documented isolated superior gluteal nerve injury following pelvic trauma. These cases illustrate that weakness in hip abduction following pelvic trauma may indicate the presence of a superior gluteal nerve injury, warranting further clinical and electrodiagnostic evaluation.

Cell wall active antifungal compounds produced by the marine fungus Hypoxylon oceanicum LL-15G256. II. Isolation and structure determination

Fermentations of the marine fungus Hypoxylon oceanicum (LL-15G256) were found to have potent antifungal activity. Isolation and purification of the antifungal agents provided two classes of compounds, macrocyclic polylactones and the lipodepsipeptides 15G256 gamma (1), 15G256 delta (2) and 15G256 epsilon (3). The isolation and structure elucidation of the lipodepsipeptides, all containing D-glutamate, L-serine, and the rare amino acid beta-ketotryptohan, are described in this paper.

Biosynthesis of ganefromycin: results from blocked mutants and bioconversion experiments

The biosynthetic pathway of ganefromycin alpha (8) was investigated using blocked mutants of Streptomyces lydicus spp. tanzanius, the ganefromycin alpha producer, in conjunction with bioconversion experiments with the products of these mutants. Compounds 1-7 and 9-15, which are structurally related to ganefromycin alpha, were produced by cultures of secretor mutants showing blockage or diminished production of 8. These compounds were isolated, characterized, and subjected to bioconversion experiments using converter and other secretor mutants. Some of the compounds were shown to be products resulting from blocks at various stages in the biosynthetics pathway beyond construction of the polyketide skeleton (e.g., furan ring closure, hydroxylation, glycosylation, etc.). Other compounds were not bioconverted by biosynthetically capable mutants and were deemed shunt products. A mutant's metabolites and bioconverting ability were used to surmise the location of the block. A picture of the later sequence of events leading to the synthesis of ganefromycin alpha emerged, including C23-hydroxylation, C13a-O-methylation, C21a-hydroxylation, and C21a-O-glycosylation. Some of the later steps in the biosynthetic pathway for ganefromycin alpha are proposed.