Objective To evaluate the effect of the plasma homocystine (Hcy) after methionine loading test (MLT) on the recurrence of ischemic vascular event,including cerebral infarction,transient ischemic attack (TIA),acute coronary syndrome,other vascularembolism,in cerebral infarction patients.Methods The fasting plasma homocystine (FHcy) and homocystine after MLT (PHcy) levels were measured by high-performance liquid chromatography.383 cerebral infarction patients with normal Hcy level were selected and divided into hyperhomocysteinemia after MLT (PHcy) group (n=135) and non-hyperhomocysteinemia after MLT (NPHcy) (n=248).Recurrence rates of ischemic vascular events within a 5-years follow-up period was observed.Results The levels of FHcy,PHcy and △Hcy (PHcy level subtracted FHcy level) were higher in males than in females in the two groups (all P＜0.05).The recurrence rates of cerebral infarction/TIA,acute coronary syndrome and other vascular embolism events were higher in PHcy group than in NPHcy group within the follow-up period (all P＜0.05).By forward stepwise logistic analysis,we found that the increased PHcy and △Hcy levels were the independent risk factors for recurrent ischemic vascular events [odds ratio (OR):0.509,2.107,95％ confidence interval (CI):0.286-0.904,1.185-3.745,both P＜0.05].Conclusions PHHcy may be an independent risk factor for recurrence ischemic vascular events in cerebral infarction.

BACKGROUND: Hyperhomocysteinemia is a new independent risk factor for coronary heart disease (CHD), but its association with cerebrovascular diseases is still controversial. The level of fasting plasma total homocysteine (plasma tHcy) alone is not enough to reveal the effect of hyperhomocysteinemia on cerebral infarction (CI).OBJECTIVE: To explore the association of hyperhomocysteinemia with folacin and vitamin B12 and with CI in young and middle-aged people, as well as the role of methionine loading test in the diagnosis of latent hyperhomocysteinemia.DESIGN: A case-control study, Spearman correlation analysis.PARTICIPANTS: A total of 85 patients were hospitalized within 2 days after the onset of CI at the Department of Neurology, the General Navy Hospital of Chinese PLA, from 2000 to 2003. There were 63 males and 22females aged 29-55 years old with the mean age of (48.74±5.05) years.There were 48 cases of lacunar CI and 37 cases of arterial thrombotic CI.Meanwhile, 44 normal controls, 30 males and 14 females aged 29-55 years old with the mean age of (47.75±6.71), were recruited from the department staff and those who came to the hospital for routine health examination.METHODS: Fasting vein blood of 6 mL was collected from the patients on the 1st day of hospitalization, and 2 mL of the blood was used for detecting the level of fasting plasma tHcy using high efficiency liquid chromatography. Methionine of 0.1 g/kg was taken orally by patients immediately after blood sampling; 4 hours later, the level of loading plasma tHcy was also determined. The remaining 4 mL was used for detecting the level of serum folacin and vitamine B12 with bioradiation assay.MAIN OUTCOME MEASURES: ① The level of fasting and loading plasma tHcy in CI group and control group. ② Incidence of hyperhomocysteinemia in CI group and control group [Hyperhomocysteinemia was confirmed if hyperhomocysteine was higher than 95% of the upper limit of fasting plasma tHcy or 4-hour loading plasma tHey of normal control group, that is, fasting plasma tHcy ＞17.26 μnol/L in males and ＞14.17 μnol/L in females; and loading plasma tHcy should be ＞ 44.57 μmol/L in males and ＞ 40.02 μmol/L in females. ③ The level of serum folacin and vitamine B12 in CI group and control group. ④ Single factor analysis of fasting plasma tHcy and related risk factors.RESULTS: Totally 85 CI patients and 44 normal controls were recruited in this study and all data were statistically analyzed. ① The level of fasting and loading plasma tHcy in CI group and control group: Both fasting and loading plasma tHcy was significantly higher in CI group than in control group [(22.49±9.80), (13.08±2.33) μmol/L; (48.07±11.20), (37.23±3.48)μmol/L, (t=8.409, 8.187, P ＜ 0.01)]. ② Incidence of hyperhomocysteinemia: The incidence was obviously higher in CI group than in control group [68% (58/85), (9%, 4/44), X2=40.628, P ＜ 0.01]. Totally 35 patients (41%, 35/85) had higher fasting plasma tHcy than that of normal controls, and 23 (27%, 23/85) had higher loading plasma tHcy than that of normal controls. ③ The level of serum folacin and vitamine B12 in CI group and control group: They were [(5.73±2.52), (7.14±2.20) μg/L] in CI group,significantly lower than control group [(473.47±190.19), (576.70±212.05) rng/L,(t =3.151, 2.809, P ＜ 0.01)]. ④ Single factor analysis of plasma tHcy with related risk factors: Fasting and loading plasma tHcy was found obviously associated with sex, and folacin and vitamine B12 level (r = -0.306 to 0.488, P ＜ 0.01), but not with other risk factors and neurological deficit scores (r = 0.021-0.173, P ＞ 0.05). Moreover, only plasma tHcy level was proved to have significant positive correlation with fasting blood glucose (r=0.186, P ＜ 0.05).CONCLUSION: Hyperhomooysteinemia is an independent risk factor for CI in young and middle-aged people. Methionine loading test is an essential means for detecting latent hyperhomocysteinemia. Insufficiency of folacin and vitamine B12, two important nutrition factors, may lead to hyperhomocysteinemia and indirectly result in CI.

Objective To study the value of methionine loading test (MLT) in the mild vascular cognitive impairment (VCI) after acute cerebral infarction.Methods The fasting plasma homocystine (Hcy) level and homocystine level after MLT were measured by high-performance liquid chromatography methods.We chose 240 patients with normal level of fasting plasma Hcy (normal group),159 patients with normal level of Hcy after MLT,81 patients with hyperhomocysteinemia after MLT (hyperhomocysteinemia group),and 112 patients with fasting hyperhomocysteinemia (fasting hyperhomocysteinemia group) in this study.The Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) were conducted in normal,hyperhomocysteinemia and fasting hyperhomocysteinemia groups on admission,at 7d,14 d,30 d after treatment.Results Logistic regression analysis showed that the increased level of Hcy might be an independent risk factor for VCI [OR:1.285,95％CI:1.038-1.265,P＜0.05].The scores of MMSE and MoCA were lower in patients with fasting hyperhomocysteinemia and patients with hyperhomocysteinemia after MLT than in patients with normal fasting plasma Hcy at 7 d,14 d and 30 d after treatment (P＜0.01 or 0.05),while the scores had no significant differences among the three group on admission (P＞0.05).There were no significant differences in MMSE and MoCA scores between patients with fasting hyperhomocysteinemia and patients with hyperhomocysteinemia after MLT on admission,7 d,14 d and 30 d after treatment (P＞0.05).Conclusions Hcy may be an independent risk factor for VCI.The MLT can discover the dormant vascular risk factors for VCI,which offers a valuable detection method for early intervention and prevention in the clinical medicine.

Objective To explore the possible effect of the plasma homocysteine level on the risk of recurrent cerebral infarction patients by follow-up research in hope for finding a new theoretical evidence for the therapy and the prophylaxis of cerebral infarction.Methods We determined the free plasma total homocysteine(tHcy)of 151 patients with acute cerebral infarction and 52 age-and gender-matched healthy controls by high-performance liquid chromatography,then we divided the patients into hyperhomocysteinemia (Hhcy)group and no hyperhomocysteinemia(Nhhcy)group according to the outcome.Within a 5-years follow-up period,we observed the recurrence of cerebral infarction in the 2 groups.Results There was no statistical deference in common information between Hhcy and Nhhcy group.But the recurrence rate of the Hhcy group,being 44.26%,was significantly higher than 12.22%of Nhhcy group(P

Objective To study the roles of the contact heat evoked potential (CHEP) in evaluating the small nerve fibers of cranial and spinal in elderly diabetic patients,and to analyze the feature of the small fibers in order to provide scientific foundations for early diagnosis of diabetic neuropathy (DN).Methods Totally 50 diabetic patients and 40 healthy subjects were included in this study.The diabetic patients were divided into the normal nerve conduction group (n=17) and the abnormal nerve conduction group (n=33).CHEP was determined and thermal stimuli was given to the area of eyelid,forearm and peroneal.Sensory and motor nerve conduction velocity in the upper and lower limbs were tested in all diabetic patients.Results Compared with the healthy group,the N wave latencies were prolonged and the N-P amplitudes were reduced in the area of eyelid,forearm and peroneal in diabetic patients (all P＜0.01).Compared with the healthy group,the logarithm of N-P amplitudes were reduced in areas of forearm and peroneal [(1.70±0.10) vs.(1.60±0.14),(1.65±0.078) vs.(1.54±0.15),both P＜0.05] and N wave latencies were prolonged in eyelid area [(343.1±18.2) ms vs.(385.4±26.5) ms,P＜0.05] in normal nerve conduction group.Compared to group with normal nerve conduction velocity,the logarithm of N-P amplitudes was reduced in peroneal area [(1.54±0.15) vs.(1.44±0.15),P＜0.05] in abnormal nerve conduction group.Conclusions CHEP can detect the early impairment of the small fibers in elderly diabetic patients.The early smallfiber impairments in diabetic neuropathy may be axon-oriented in spinal nerves and myelin-oriented in cranial nerves.

Objective To evaluate the function status of motor nerve in patients with carpal tunnel syndrome ( CTS) sensory neuropathy by single-fiber conduction studies ( SF-CS).Methods Forty patients with CTS were divided into two groups according to the nerve conduction abnormality of median nerve .The sensory conduction abnormalities ( SCA) group included 20 patients with abnormal sensory conduction , while the sensory motor conduction abnormalities ( SMCA) group included 20 patients with abnormal motor sensory conduction.The Keypoint.net electromyogram device was used to detect the wrist to the abductor pollicis brevis latency , using the saddle shaped stimulating electrodes for stimulating and the single fiber electromyography electrode for recording.The control group included 20 healthy people.Results The latency of single-fiber conduction of median nerve in SCA group , SMCA group and control group was (3.92 ±0.28) ms, (4.71 ±0.49) ms and (3.41 ±0.31) ms (F=63.829, P=0.000), respectively.The area under the receiver operating characteristic curve was 0.920 for the latency of single-fiber conduction of median nerve , and its specificity was 85%in cut off point.Conclusions There is clinical motor nerve damage in patients with CTS sensory neuropathy.The SF-CS may become an effective means for early evaluation of motor nerve function state.

Objective To evaluate the impairment of ulnar nerve and its relationship with sensory symptoms in the ulnar territory in patients with carpal tunnel syndrome (CTS) through electrophysiological approach.Methods We retrospectively reviewed 55 cases with CTS admitted in our hospital from January 2012 to February 2013.Patients with CTS were graded as mild-moderate (35 cases) and severe (20 cases) according to Stevens standard and were divided into symptomatic and non-symptomatic group according to the presence of sensory symptom in little finger region.Twenty healthy volunteers were included as control.Median and ulnar nerves electrophysiological study were performed using the Keypoint.net (Medoc Ltd) electromyogram device.Results Finger 5-wrist sensory conduction velocities (SCVs) of ulnar nerve were reduced ((51.71 ± 2.93) m/s vs (58.62 ± 3.21) m/s,t =8.80,P ＜ 0.01) in CTS group,compared with control group.But the sensory nerve action potential (SNAP) amplitudes had no difference.Pearson correlation analysis showed that finger 5-wrist SCVs and the SNAP amplitudes of ulnar nerve were negatively correlated with the distal motor latency of the median nerve,while positively correlated with the compound muscle action potential amplitudes,finger 1-wrist,finger 3-wrist SCVs and SNAP amplitudes of median nerve,in mild-moderate group,finger 5-wrist SCVs of ulnar nerve were slowed and the SNAP amplitudes were reduced ((51.59 ±2.70) m/s vs (53.72 ±2.58) m/s; (13.51 ± 1.84) μV vs (15.21 ±2.16) μV,t =2.24,2.30,P ＜ 0.05 respectively) in the symptomatic group,compared with the non-symptomatic group.However,in severe group,only 2 cases had sensory symptom in little finger region.Conclusions CTS patients may have impairments due to ulnar nerve entrapments at wrist,which aggravate with disease progression.Sensory symptoms in ulnar territory are more frequent during the mild-moderate stage,and may relate with ulnar nerve involvement.

Objective To investigate a non-invasive and objective measure for patients with diabetic small fiber neuropathy by contact heat evoked potential (CHEP). Methods CHEP was performed in diabetic patients (n=46) and normal subjects (n =40). Thermal stimuli were given at 52 ℃ to 3 body sites: right forearm, right dersum hand and right peroneal area. CHEP were recorded from Cz. The main components of CHEP were observed. Studies on sensory nerve conduction were performed in all the diabetic patients and the normal subjects. Results In 7 patients there were no recordable CHEP on stimulation of the forearm, and in some cases of dorsum hand (n =9) and the leg (n = 16). In contrast, CHEP were recordable in all control subjects. The diabetic group had reduced N-P amplitudes and prolonged N-wave latencies. In patients with normal sensory nerve conductions, amplitudes of CHEP were reduced and latencies of CHEP were prolonged. Twenty-five patients had normal sensory nerve conduction for upper limbs, the amplitudes of CHEP being (34.0±12.6) μV vs (48.4±17.5)μN, Z= -3. 151, P<0.01 for the forearm, (28.2±10. 1) μV vs (43.0±16.6) μV, Z= -3.712, P<0.01 for the dersum hand with a latency of (420.4±27.8) ms vs (407.2±24.6) ms, t =2.015,P=0.048. In 18 patients with normal sensory nerve conductions for lower limbs, the latency of CHEP for the leg was (473.5±46. 6) ms vs (448.6±35.0) ms, t =2. 219 (P =0. 031) and amplitudes (23. 8±7.4) μV vs (41.5 ±18.5) μV, Z = - 3. 855 (P <0.01). Conclusion CHEP provides an objective and non-invasive potential clinical utility in the evaluation of diabetic small fiber neuropathy.

Objective To analyze the electrophysiologie characteristics of critical illness of polyneuromyopathy ( CIPM ) and its effect on the duration of usage of mechanical ventilation. Methods Denmark Keypoint 4-electromyogram was utilized to record electraneurophysiology on 17 subjects with lung infection and respiratory failure who were treated with mechanical ventilation over 1 week and had difficulty in weaning from the ventilator in intensive care unit. Electrophysiology character of CIPM was described and the duration of mechanical ventilation of CIPM patients was compared with non-CIPM subjects. ResultsOf the 17 cases, 9 subjects were diagnosed with CIPM including 6 patients with critical illness polyneuropathy (CIP), and 3 patients with critical illness myopathy (CIM), the 2 subtype of CIPM. Compound muscle action potential (CMAP) and sympathetic skin response (SSR) in all of CIPM patients were abnormaL Though the amplitude of sensory nerve action potential (SNAP) in patients with CIP was reduced, nerve conduction velocity (NCV) was normal in all of them. Repetitive nerve stimulation, somatosensory evoked potential and blink reflex were normal in all of the patients with CIPM, however, the rate of occurrence of F wave was reduced in 2 patients with CIP and in 2 patients with CIM. The median and quartile range of duration of mechanical ventilation in CIPM patients was 30. 0 days (20. 0--45.0 days), significantly longer than13.5 days (9.5--17.5 days) in non-CIPM patients (U=7.500,P=0.006). ConclusionsThe ehctrophysiology change in patients with CIPM is characterized by reduced amplitude of CMAP and (or) SNAP, normal NCV and abnormal SSR. The duration of mechanical ventilation is significantly prolonged in CIPM patients.

Objective To investigate motor nerve function status in rats with diabetes mellitus by motor unit number estimation (MUNE), and discuss it′s early diagnostic value in diabetic peripheral neuropathy (DPN). Methods Diabetic rat model (DM group) was induced by streptozotocin. The MUNE of gastrocnemius muscle and motor nerve conduction (MCV, CMAP) of the sciatic nerve were measured at the 4th, 8th and 12th week after onset of hyperglycemia in the DM group and the control group (normal SD rats). The ultrastructure of sciatic nerve was observed by electron microscope. Results At the 4th week, MUNE of gastrocnemius muscle was significantly decreased in DM group compared to that of the control group (275.88 ± 87.87 vs 369.71 ± 75.64,P<0.05). There were no significant differences in MCV and CMAP of sciatic nerve be?tween two groups. The electron microscopy observation showed that most nerve fibers were normal;a small amount of axonal atrophy, and myelin lamellar structure was separated in DM group. At the 8th week, compared with the control group, MUNE were reduced in gastrocnemius muscle in DM group (357.49±72.68 vs 221.26±92.41, P<0.01). There were no significant dif?ferences in MCV and CMAP of the sciatic nerve between DM group and control group. The electron microscope observation showed that part of nerve fibers were normal, the myelin focal plate layer was loose and separated, axonal atrophy, the axonal membrane and myelin sheath inner layer was separated with big gap. At the 12th week, MUNE of gastrocnemius muscle (127.87±19.80 vs 366.85±51.25), sciatic nerve MCV [(35.06±4.43) m/s vs (50.47±6.07) m/s] and CMAP [(2.91±1.37) mV vs (5.98±2.14) mV] were significantly decreased in DM group than those of control group (P<0.01). The electron microscopy observation showed severely damaged myelin flex and axonal squeeze. Conclusion MUNE is much earlier in detecting ear?ly motor nerve dysfunction in DM than conventional motor nerve conduction test.