Folate supplementation after heart transplantation: effects on homocysteine plasma levels and allograft vascular disease.

BACKGROUND AND AIMS: After heart transplantation, the effects of folate supplementation on total homocysteine plasma levels (THcy) and heart allograft vascular disease (AVD) remain unclear. METHODS: Accordingly, we prospectively analyzed 48 heart transplant receipients referred for routine follow-up from July to September 1998 (age 54+/-11 years, 75% male, 35+/-27 months from transplant). Among these patients, 17 were treated with folate supplementation for 12 months (Group F), while 31 cross-matched for age, gender, serum creatinine and time from transplant (P>0.3 vs Group F for all) did not assume folate supplementation (Group NF). Routine coronary angiography for AVD detection was routinely obtained in every patient. RESULTS: THcy overall increased during the study period (from 16.6+/-6.5 to 19.4+/-7.6 micromol/l, P<0.001), and a strong trend toward higher THcy was observed in patients presenting AVD (22.4+/-8.7 vs 17.6+/-6.8 micromol/l, P=0.051). After 12 months THcy was lower in Group F as compared to Group NF (16.2+/-5.6 vs 21.1+/-8.1 micromol/l, respectively, P=0.033). CONCLUSIONS: Our results demonstrate that THcy increases over time in heart transplant recipients, and a strong trend toward higher THcy is observed in the presence of AVD. Since folate supplementation appears to positively influence THcy, a favorable effect of folate on AVD can be hypothesized.

Influence of gender on auditory startle responses.

The auditory startle reaction is considered a brainstem reflex in response to an unexpected loud stimulus. It may be abnormal in various neurological conditions. However, the influence of gender on physiological characteristics of auditory startle responses (ASRs) in humans has to date been studied only in orbicularis oculi muscle. We investigated 54 healthy adult subjects (27 males, 27 females). ASRs were elicited by binaural high-intensity auditory stimuli which differed randomly in tonal frequency and intensity (250 Hz-90 db; 500 Hz-105 dB; 750 Hz-110 db, 1000 Hz-110 dB nHL), presented through tubal insert phones. Reflex electromyographic activity was simultaneously recorded with surface electrodes from masseter, orbicularis oculi, sternocleidomastoid, biceps brachii, abductor pollicis brevis, rectus femoris, tibialis anterior, and soleus muscles. ASR probability was significantly lower, and ASR area under the curve was significantly smaller, in men versus women. Median onset latencies did not differ significantly, but tended to be shorter in the lower extremities of men despite greater body height. Habituation, measured as a reduction in response probability with repeated stimulation, was significant in all muscles except orbicularis oculi in both men and women. Our data provide evidence for a significant influence of gender on ASR characteristics. The observed differences are likely due to gender-specific variations of central processing in the brainstem centers involved in ASR generation, and should be taken into account when testing ASRs in health and disease.

Influence of age on auditory startle responses in humans.

The auditory startle reaction is considered a brainstem reflex in response to an unexpected loud stimulus. We investigated the influence of age on auditory startle responses (ASRs) in 54 adult healthy subjects separated in three age groups (below 30; 30 to 50; above 50 years). ASRs were elicited by auditory stimuli randomly presented through tubal insert phones. Reflex electromyographic activity was simultaneously recorded from eight facial, neck, and extremity muscles. ASR probability was lower in extremity muscles of younger versus older subjects, but did not differ among age groups in facial and neck muscles. Median ASR latencies were significantly shorter in all muscles of younger versus older subjects. Our data provide evidence of a significant influence of age on ASRs. The observed differences are likely due to age-specific variations of central processing in the brainstem centers involved in ASR generation.

The auditory startle reaction in parkinsonian disorders.

The auditory startle reaction to an unexpected loud stimulus is regarded as a brainstem reflex originating in the nucleus reticularis pontis caudalis and being distributed up the brainstem and down the spinal cord along slowly conducting pathways. Auditory startle responses (ASR) have been reported absent or reduced in progressive supranuclear palsy (PSP), and delayed in Parkinson's disease (PD), but normal in multiple-system atrophy (MSA). For the first time we studied ASR in patients fulfilling the clinical criteria of dementia with Lewy bodies (DLB) (n = 8), a neurodegenerative disorder characterized by cortical and subcortical depositions of Lewy bodies resulting in parkinsonism and progressive cognitive decline. For comparison, we also investigated patients with PD (n = 10), MSA (n = 7), PSP (n = 10), and age-matched healthy controls (n = 10). ASR were elicited by binaural high-intensity auditory stimuli. Surface electromyographic activity was simultaneously recorded from facial, upper, and lower extremity muscles. For each muscle, we assessed response probability and measured latency, amplitude, duration, and habituation rate. Patients with DLB had fewer and abnormally delayed ASR of low amplitude and short duration in extremity muscles compared to healthy controls. Furthermore, we confirm and extend previous findings of abnormal ASR in PSP and PD, and also demonstrate exaggerated ASR in extremity muscles of MSA patients. The different patterns of ASR abnormalities may reflect distinct types of brainstem dysfunction in DLB.