Faculty Bibliography

Diabetic amyotrophy is a disabling illness that is distinct from other forms of diabetic neuropathy. It is characterized by weakness followed by wasting of pelvifemoral muscles, either unilaterally or bilaterally, with associated pain. Sensory impairment is minimal in the cutaneous distribution sharing the same root or peripheral nerve as affected musculature. Most commonly, the onset is in middle age or later, although it may occur in youth. A concomitant distal predominantly sensory neuropathy may be present. Electrodiagnostic studies are most often consistent with a neurogenic lesion attributable to a lumbosacral radiculopathy, plexopathy, or proximal crural neuropathy. The natural course of the illness is variable with gradual but often incomplete improvement. The site of the lesion and the pathogenesis of diabetic amyotrophy remain controversial. Recent studies suggest a role for immunomodulating agents in certain types of diabetic neuropathy, including diabetic amyotrophy

A case fulfilling the criteria for the diagnosis of diabetic amyotrophy is reported. Based on the clinical and electrodiagnostic features, it is concluded that diabetic amyotrophy is a recognizable clinical entity that can be differentiated from other diabetic neuropathies. The site of the lesion and the pathogenesis in diabetic amyotrophy remain controversial. The course of the illness is variable with gradual, but often incomplete, improvement

Two siblings with proximal myotonic myopathy (PROMM), a hereditary disorder, had predominantly proximal weakness, pain, and gait impairment aggravated by warm temperatures. EMG of the deltoid showed sparse abnormal spontaneous activity at room temperature and with cooling. Warming induced frequent myotonic discharges and fibrillations. Profuse myotonia recorded at room temperature in the first dorsal interosseous abated following cooling. Repetitive stimulation did not reveal a decrement recording from distal muscles, but recording from the deltoid, in the one patient tested, revealed a significant decrement that did not improve with edrophonium. Myopathic motor units were recorded only in distal musculature. The myotonia of PROMM is provoked by heat and diminished by cold and may have a different physiologic basis than traditional myotonic syndromes

In both rats and humans there is an analgesia associated with pregnancy. This analgesia is spinally mediated and involves the kappa type of opiate receptor. The current study demonstrates that intrathecal administration of high affinity dynorphin antibodies produces a significant reduction in jump thresholds during pregnancy (day 20). The administration of pre-adsorbed antisera fails to produce this effect. These results support the hypothesis that a spinal dynorphin/kappa opiate receptor system is activated during gestation

In a variety of laboratory animals as well as humans, pregnancy has been associated with an activation of a maternal opioid system(s) and with a concomitant elevation in the threshold for maternal responsiveness to aversive stimuli. This analgesia is mediated via the activation of spinal opiate receptors and does not require an intact peripheral opioid system(s). The recently developed kappa-selective opioid antagonist, nor-binaltorphimine (nor-BNI), significantly reduces the threshold for reflexive jumping in response to electric foot shock when administered to the lumbar intrathecal (i.t.) space of pregnant rats (day 20 of gestation). In contrast, i.t. nor-BNI when administered to non-pregnant rats as well as systemic (i.p.) administration of an intrathecally effective dose of nor-BNI to pregnant rats is without effect on the jump thresholds. These data indicate that the kappa-type of opiate receptor mediates, at least in part, the analgesia observed during gestation, thus providing an important physiological function for this receptor type

It has been demonstrated that during pregnancy and labor in rats and humans there is an opioid-mediated elevation in the threshold for responsiveness to aversive stimuli which reaches a maximum at term. Acute administration of the opiate antagonist, naltrexone, into the lumbar intrathecal (i.t.) space of pregnant rats (day 20 of gestation) significantly reduces the threshold for reflexive jumping in response to electric footshock. The i.t. administration of the inactive stereoisomer of a closely related narcotic antagonist, (+)-naloxone, is devoid of any effect on pain threshold. No effect on the pain threshold is observed following intrathecal saline administration to pregnant rats, i.t. naltrexone administration to non-pregnant rats or following systemic administration of an intrathecally effective dose of naltrexone to pregnant rats. These data indicate that the analgesia observed during gestation is mediated, at least in part, via a spinal opioid pathway which is activated by some aspect of the pregnant condition