Manabu Sakuta

Rodent eccrine sweat glands: A case of multiple efferent innervation

The sweat territories of peripheral nerves to the hind-paw of the mouse were defined by a silastic impression mold method that allowed identification of every secreting sweat gland. It was found that the tibial, sural, saphenous and peroneal nerves all contribute to the innervation of foot pad sweat glands, and there is extensive overlapping of the sweat territories of the different peripheral nerves. Most sweat glands could be activated by electrical stimulation of axons in two or three peripheral nerves or in separate fascicles of one nerve. This was interpreted to indicate that these sweat glands receive multiple innervation and that sweat glands in the overlap regions between autonomous zones of adjacent cutaneous nerves can receive axons from each nerve. Partial denervation of sweat glands by section of one source of innervation did not prevent the gland from sweating during stimulation of intact axons to the gland, or after pilocarpine treatment. Totally denervated glands did not exhibit denervation hypersensitivity; they became unresponsive to pilocarpine, acetylcholine and adrenaline. These characteristics allowed detection of the appearance and progression of reinnervation (and reactivation) of denervated sweat glands by collateral branching from sudomotor fibers. Not only do these results increase our basic understanding of the anatomical relations between peripheral nerves and the sweat glands they innervate, but they also demonstrate that the mouse sweat gland provides a useful model system for studying neuropathology of the sympathetic nervous system.

Physiological and Clinical Correlates of Cardiorespiratory Reflexes in Diabetes Mellitus

Cardiorespiratory reflexes (CRRs) were studied by measuring heart-rate (HR) variation during 6 breaths/min respiration (ΔR6) and Valsalva maneuver (VR) in 145 healthy and 417 type I (insulin-dependent) diabetic subjects. HR variation with breathing at 12 breaths/min and ventilatory response to hypercapnia/hypoxia were measured in fewer subjects. CRR results were compared with symptoms of autonomic dysfunction, the neurological examination, nerve conduction studies, and quantitative sweat testing. The objective was to compare the sensitivity of various methods of characterizing diabetic patients and to use this information when staging patients for clinical therapeutic trials. CRR responses were age dependent in both populations. Either ΔR6 or VR was abnormal in 74% of diabetic patients, Δ R6 being more sensitive. CRRs correlated well with the presence of symptoms of autonomic dysfunction, abnormalities on the neurological examination, results of nerve conduction studies, and sweating activity in the feet of the same patients. However, both CRRs and sweating were abnormal in a high proportion of patients without any clinical manifestations of neuropathy. The ventilatory reflex response to moderate hypercapnia/hypoxia was also measured. It was normal in most of the diabetic patients tested, including many with severe reduction of CRRs. We conclude from the combined results of CRR, ventilatory response, and other studies that the causative factors for abnormal CRR may not be confined to the vagus nerves, and that in most instances, the depressed CRR may be due to a decrease in the efficacy of sensorimotor nerve conduction around the reflex arc.

Anal muscle electromygrams differ in amyotrophic lateral sclerosis and Shy‐Drager syndrome

Electromyography (EMG) of anal sphincter muscles was different in patients with amyotrophic lateral sclerosis (ALS) and Shy-Drager syndrome. In 30 patients with ALS, EMG of the external sphincter muscle was essentially normal, with no signs of denervation. In eight cases of Shy-Drager syndrome, however, motor unit potentials of the anal sphincter had highly polyphasic forms of long duration and high amplitude. In the Shy-Drager syndrome, there seems to be specific damage of lower motor neurons that innervate the external sphincter muscle of the anus.

A Clinical Profile of Corticobasal Degeneration Presenting as Primary Progressive Aphasia

We report a patient with primary progressive aphasia who first presented with amnesic aphasia that developed over the course of 3 years into nonfluent aphasia with buccofacial apraxia, followed in the next year by cognitive impairment and parkinsonism. Pathological findings were typical for corticobasal degeneration except for the distribution of cortical atrophy. This case suggests that corticobasal degeneration should be included in the differential diagnosis of primary progressive aphasia, especially in association with parkinsonism.

The sweating deficiency in diabetes mellitus Methods of quantitation and clinical correlation

A method that measures the amount of sweat evaporating from the skin was used to quantitate the sweating deficiency that accompanies diabetic neuropathy. The decreased amount of sweat secreted after pilocarpine stimulation was proportional to the reduction in number of excitable sweat glands, and to the decrease in water measured by the summed volume of all sweat droplets secreted. The results also correlated favorably with the degree of sensory loss to painful stimuli, but not to the alpha motor nerve conduction velocity or motor axon loss evaluated by muscle action potentials evoked from foot muscles. Respiratory-cardiovascular reflexes, as measured by the Valsalva ratio, were always abnormal in patients with demonstrated sweating deficiency and often in patients with normal sweat function.

Mechanism of short-term memory and repetition in conduction aphasia and related cognitive disorders: a neuropsychological, audiological and neuroimaging study

To evaluate the role of the sub-cortical white matter and cortical areas of the supramarginal gyrus in short-term memory impairment (shortened digit or letter span) and repetition difficulty, four patients with conduction aphasia and impaired short-term memory and two patients with only short-term memory impairment were given digit span, letter span, speech audiometry and dichotic listening tests. The results showed that in most of the patients letter span was inferior to digit span and that bilateral ear suppression in the dichotic listening test was observed in two patients with a lesion in the inferior part of the supramarginal gyrus, suggesting that what was affected was phonological information and that the supramarginal gyrus was the storage site. The overlapped lesion of conduction aphasia patients with short-term memory impairment was the periventricular white matter at the upper to middle part of the trigone, while patients with only short-term memory impairment had a lesion in the inferior supramarginal gyrus in common. Thus, damage to the periventricular white matter at the trigone may yield the phonemic paraphasia characteristic of conduction aphasia, while damage to the inferior part of the supramarginal gyrus may result in the impairment of short-term memory. We believe that as a part of the mechanisms of short-term memory and repetition, phonological information is processed in the primary auditory cortex and goes through the periventricular white matter to the inferior part of the supramarginal gyrus and is temporarily stored there.

Autoantibodies in postinfectious acute cerebellar ataxia

The authors found serum immunoglobulin M (IgM) autoantibody in a patient with typical acute cerebellar ataxia (ACA) and identified the antigen molecule as triosephosphate isomerase (TPI). TPI antigenicity to the patient’s antibody was the highest in the cerebellar tissue. Eight of 23 patients with ACA had increased IgM anti-TPI antibody titers vs those of healthy controls. Preceding Epstein–Barr virus infection was confirmed serologically in all 8 patients. Anti-TPI antibody decreased with clinical improvement.

Giant somatosensory evoked magnetic field in patients with myoclonus epilepsy.

We investigated somatosensory evoked magnetic fields (SEFs) and somatosensory evoked potentials (SEPs) in patients with myoclonus epilepsy. The median nerve was stimulated at the wrist, and responses were recorded over the contralateral hemisphere. The source of the enlarged cortical component of the giant SEF was localized on the post-central sensory cortex. The P1 component of the giant cortical response was composed mainly of a tangentially oriented dipole at area 3b. This is the first magnetoencephalographic analysis of an abnormally enlarged somatosensory cortical response.

Pure Progressive Autonomic Failure: A Clinicopathological Study

Two cases of pure progressive autonomic failure (PAF) are presented. A postmortem study of one case (case 2) showed a pathology resembling that of Parkinsons disease. Marked cell loss was noted in the substantia nigra, nucleus ceruleus, and intermediolateral column of the spinal cord, while cell loss in the sympathetic ganglion was not remarkable. This case may be an exceptionally rare case of late-onset PAF in which autonomic failure was mainly ascribed to preganglionic (and central) pathology, although autonomic function tests suggested postganglionic sympathetic disorder in both cases.

Positron emission tomography of reversible intellectual impairment induced by long-term anticholinergic therapy

Long-term oral anticholinergic (AC) therapy can occasionally produce intellectual impairment. We investigated a patient with Parkinsons disease accompanied by intellectual impairment induced by long-term AC therapy. The intellectual impairment of the patient disappeared after cessation of AC therapy. Positron emission tomography (PET), during and after long-term oral AC therapy, revealed that it causes bilateral diffuse decrease of glucose metabolism in the cortex, basal ganglia, thalamus, hippocampus and cerebellum. Cessation of the therapy resulted in diffuse increase of glucose metabolism in all of the above regions. Cranial CT and magnetic resonance imaging (MRI) showed no abnormalities. Our results suggest that long-term AC therapy causes reversible bilateral diffuse glucose hypometabolism.