Interhemispheric asymmetry in brain perfusion before and after carotid stenting: a 99mTc-HMPAO SPECT study.

PURPOSE: To assess the effect of unilateral carotid angioplasty and stenting (CAS) on cerebral perfusion asymmetry in patients with severe extracranial carotid stenosis by means of technetium Tc 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography ((99m)Tc-HMPAO SPECT). METHODS: Twenty-nine consecutive patients (22 men; median age 68 years, range 58-80; 13 symptomatic) undergoing unilateral CAS were included in the study. Brain perfusion was assessed by (99m)Tc-HMPAO brain SPECT prior to the procedure and postoperatively at 8 hours and at 2 to 4 months. The asymmetry index (AI), a measure of the interhemispheric asymmetry in perfusion, was calculated as [(counts in "healthy" hemisphere-counts in hemisphere with carotid stenosis)/counts in "healthy" hemisphere]x100. RESULTS: The preoperative AI demonstrated a wide variation (mean -0.5%+/-8.4%, range -19.5% to 14.1%). There was no significant correlation between the degree of carotid stenosis and preoperative AI. The mean preoperative AI in the asymptomatic patients was lower than in the symptomatic group [-4.0%+/-8.5% (range -19.5% to 8.2%) versus 3.8%+/-6.4% (range -5.2% to 14.1%), p=0.01], suggesting reduced perfusion of the ipsilateral cerebral hemisphere compared to the contralateral side in symptomatic patients. AI variation did not improve after CAS; there was no difference in AI among the 3 SPECT studies (p=0.75). Preoperative AI correlated significantly with late AI (r=0.74, p<0.0001); however, there was no statistically significant correlation between immediate postoperative AI and either preoperative (r=0.24, p=0.217) or late (r=0.24, p=0.249) AI. CONCLUSION: Asymmetry in cerebral perfusion in patients with severe extracranial carotid atherosclerosis does not correlate with the degree of carotid stenosis. Symptomatic patients demonstrate compromised perfusion of the ipsilateral hemisphere compared to asymptomatic patients. As judged by (99m)Tc-HMPAO SPECT scanning, cerebral perfusion patterns do not significantly change after CAS.     

Cerebral SPECT with 99mTc-HMPAO in extracranial carotid pathology: evaluation of changes in the ischemic area after carotid endarterectomy.

The authors report their experience in studying patients undergoing carotid endarterectomy with simple photon emission computed tomography (SPECT). This technique made it possible to identify areas of preoperative cerebral hypoperfusion in 54.8% of the patients which had a good correlation with neurological symptoms. To distinguish gradual changes in the ischemic lesions, a method of assessing the surface of the hypoperfused areas was adopted. In addition, SPECT made it possible to detect a greater number of hypoperfused areas even in sites other than those revealed by CT. Moreover, there was good correlations between the SPECT data and the grade and site of the carotid lesion and the data provided by some intraoperative monitoring procedures. The Authors therefore propose the use of SPECT in the evaluation of patients with cerebrovascular insufficiency following a carotid disease.     

Cerebral microglia activation in hepatitis C virus infection correlates to cognitive dysfunction

Hepatitis C virus (HCV) infection may induce chronic fatigue and cognitive dysfunction. Virus replication was proven within the brain and HCV‐positive cells were identified as microglia and astrocytes. We hypothesized that cerebral dysfunction in HCV‐afflicted patients is associated with microglia activation. Microglia activation was assessed in vivo in 22 patients with chronic HCV infection compared to six healthy controls using [¹¹C]‐PK11195 Positron Emission Tomography (PET) combined with magnetic resonance tomography for anatomical localization. Patients were subdivided with regard to their PCR status, Fatigue Impact Scale score (FIS) and attention test sum score (ATS). A total of 12 patients (54.5%) were HCV PCR positive [of which 7 (58.3%) had an abnormal FIS and 7 (58.3%) an abnormal ATS], 10 patients (45.5%) were HCV PCR negative (5 (50%) each with an abnormal FIS or ATS). Patients without attention deficits showed a significantly higher accumulation of [¹¹C]‐PK11195 in the putamen (P = 0.05), caudate nucleus (P = 0.03) and thalamus (P = 0.04) compared to controls. Patients with and without fatigue did not differ significantly with regard to their specific tracer binding in positron emission tomography. Preserved cognitive function was associated with significantly increased microglia activation with predominance in the basal ganglia. This indicates a probably neuroprotective effect of microglia activation in HCV‐infected patients.     

Factors associated with sexual dysfunction in men with HIV infection

Where men have had access to successful treatment for HIV (highly active antiretroviral therapy), expectations of both patients and physicians alike have changed significantly over the past decade. Such men, living with HIV, expect to lead fully functional lives including a normal sex life. Sexual dysfunction is well described among men with HIV. We retrospectively analysed details of 190 consecutive men attending a dedicated sexual dysfunction service in our HIV unit over an 18-month period. We took note of the specifics of their HIV disease, illnesses other than HIV, as well as other risk factors associated with sexual dysfunction. Men with sexual dysfunction all commonly reported recreational drug use, hepatitis B and C co-infection, anxiety and depressive illnesses, peripheral neuropathy and lipodystrophy. There was a significant relationship between men complaining of retarded ejaculation and peripheral neuropathy. Sexual dysfunction in non-HIV settings is known to lead to poor adherence to prescribed medications, e.g. antihypertensive agents. Iatrogenic sexual dysfunction in patients may similarly have a potential to lead to poor antiretroviral compliance if not addressed.     

硝酸酯心肌灌注显像估价冠心病合并左心室功能不全患者的预后

目的　评价硝酸酯99Tcm MIBI心肌灌注显像在冠心病合并左心室功能不全患者中的预后价值。方法　 87例进行了静息 硝酸酯99Tcm MIBI心肌灌注显像的患者 ,冠状动脉造影证明所有患者均存在明显的冠状动脉狭窄 (≥ 5 0 %)。并进行了随访。结果　硝酸酯99Tcm MIBI心肌灌注显像提示有灌注异常 ,但心肌存活的 38例 ,其中接受冠状动脉再血管化的 2 2例 ,接受药物治疗的 1 6例 ;灌注异常、心肌不存活的 4 9例 ,其中接受冠状动脉血管重建和药物治疗的分别为 30例和 1 9例。平均随访 (2 3± 1 4 )个月。随访期间共发生 2 0例心脏事件 (心脏性死亡 6例、非致死性心肌梗死 4例、不稳定性心绞痛 5例、难以控制的心力衰竭 5例 )。在有存活心肌的患者中 ,接受药物治疗患者的心脏事件发生率明显高于接受冠状动脉血管重建治疗的患者 (6 2 5 %比 4 5 %;χ2 =1 5 1 3,P <0 0 0 5 ) ;在心肌不存活的患者中 ,接受血管重建和药物治疗患者的心脏事件发生率差别无显著性 (1 6 7%比2 1 1 %;χ2 =0 1 5 ,P =NS)。结论　对于冠心病合并左心室功能不全患者 ,硝酸酯心肌灌注显像有重要的预后价值     

Autonomic nervous system dysfunction associated with HIV infection in intravenous heroin users.

OBJECTIVE: To evaluate the presence of autonomic nervous system (ANS) involvement in HIV-positive drug users. DESIGN: We investigated 37 HIV-positive (and 18 HIV-negative controls) intravenous heroin users who were without symptoms and signs of autonomic or peripheral neuropathy. METHODS: The patients were clinically and immunologically assessed and subjected to a battery of five cardiovascular reflex function tests. RESULTS: The tests revealed ANS involvement in 22 HIV-positive subjects but only in one HIV-negative subject. Immunoglobulin (Ig) G and C1q immune complex levels were significantly higher in HIV-positive subjects with severe cardiovascular reflex function tests alteration compared to those with normal tests. In a follow-up of 17 HIV-positive subjects, nine presented deteriorated reflexes in the tests and higher IgG immune complex levels. CONCLUSIONS: The results confirm that, by using sufficiently sensitive tests, signs of preclinical autonomic neuropathy can frequently be found in HIV-positive intravenous heroin users, as previously observed in homosexual patients, and suggest the existence of an HIV-related autoimmune pathogenesis. Early diagnosis of ANS involvement could be important, since the presence of autonomic dysfunction could increase the risk of cardiorespiratory arrest during invasive procedures.     

Technetium-99m pyrophosphate uptake in experimental viral perimyocarditis. Sequential study of myocardial uptake and pathologic correlates

The myocardial uptake of technetium-99m pyrophosphate (99mTc-PYP) in perimyocarditis induced by coxsackievirus B3 in BALB/c mice was studied. 99mTc-PYP uptake ratio, measured by the ratio of counts/min per gram for the heart to counts/min per gram for the skull, began to increase 5 days after virus inoculation when myocardial necrosis was evident. On the seventh day after the inoculation, 99mTc-PYP ratio reached a maximum. Histologically, fine, dystrophic calcification appeared in the necrotic fibers. 99mTc-PYP uptake was in proportion to the extent of the myocardial lesions. Thereafter, cellular infiltrations increased with time and were most severe on the fourteenth day, but 99mTc-PYP ratio had begun to fade. On the twenty-eighth day, perimyocardial fibrosis increased and calcification was still present, but 99mTc-PYP ratio had decreased. Myocardial uptake with severe pathologic lesions was visualized on a whole-body image on the seventh day after inoculation with the virus. The findings may provide a basis upon which 99mTc-pyp imaging may be applied to viral perimyocarditis in humans.     

Thymus volume correlates with the progression of vertical HIV infection

BACKGROUND: The thymus is the organ responsible for the maturation and selection of T lymphocytes and is thus pivotal in allowing the development of a functional immune system. Because in HIV infection cell-mediated immune responses are severely impaired, we studied the role of thymus in the control of the progression of HIV infection to AIDS. METHODS: Thymic volume was analysed by magnetic resonance imaging in 31 vertically HIV-infected children. Plasma HIV viral load and phenotypic and functional cellular immunity-defining parameters were examined in the same patients. RESULTS: Thymic volume was not correlated with age or nutritional status; thymic volume was nevertheless correlated with CD4 T-lymphocyte counts and with the percentage and absolute number of CD45RA+CD62L+ (naive) T lymphocytes. In addition, the ability of peripheral blood mononuclear cells to proliferate upon tetanus stimulation was directly proportional to thymic volume. Finally, a negative correlation was detected between thymic volume and HIV viral load. CONCLUSION: Because low HIV plasma viraemia and preserved immune function are favourable prognostic indices in HIV disease, these data indicate that an immunological, thymic-dependent control of the progression of HIV infection might be possible, at least in vertically transmitted HIV infection.     

Alzheimer病认知功能与脑SPECT关系初步探讨

目的探讨Ａｌｚｈｅｉｍｅｒ病（ＡＤ）患者认知功能和脑功能区的血流改变及其两者之间的关系。方法４０名ＡＤ患者、３５名年龄和性别相对应的正常老年人均予认知功能及脑ＳＰＥＣＴ检查，并做相关性研究。结果ＡＤ患者的认知功能与同年龄组老年人相比有明显减低（Ｐ＜０．００１），ＡＤ患者两侧大脑半球血流均有，但各功能区血流减低的程度不一样，其中以顶、颞、额叶、基底节血流降低的程度最为明显（Ｐ＜０．００１），丘脑、枕叶血流降低程度与对照组相比也有统计学上的差异（Ｐ＜０．０１，Ｐ＜０．０５）。相关性研究发现，ＡＤ患者语言和视觉空间障碍与左颞叶血流降低有关（Ｐ＜０．０５），注意力和记忆力的障碍则与右额叶关系密切（Ｐ＜０．０５）。结论ＡＤ患者存在认知功能障碍，其双侧大脑半球血流全面降低，且认知功能障碍与脑相关功能区低灌注密切相关。     

Tuberculosis incidence in developing countries with high prevalence of HIV infection.

OBJECTIVE: To study the impact of the HIV epidemic on tuberculosis (TB) incidence in developing countries. DESIGN: A simple mathematical model is constructed using figures from published reports to estimate the rise of TB incidence as the HIV epidemic expands. METHOD: Two groups with different risk of developing TB are identified: individuals with dual infection of HIV and Mycobacterium tuberculosis and the rest of the population. The model is based on a combination of the incidence and the percentage of TB in these two groups. The expected rise in TB incidence and the percentage of TB cases that will be HIV-positive are plotted against the prevalence of HIV. CONCLUSIONS: Unless appropriate action is taken, TB incidence in developing countries will double as the prevalence of HIV infection reaches 13 per hundred adults.     

Routine, voluntary HIV testing in Durban, South Africa: correlates of HIV infection

Background

Routine HIV testing is increasingly recommended in resource‐limited settings. Our objective was to evaluate factors associated with a new diagnosis of HIV infection in a routine HIV testing programme in South Africa.

Methods

We established a routine HIV testing programme in an out‐patient department in Durban, South Africa. All registered adults were offered a rapid HIV test; we surveyed a sample of tested patients.

Results

During the 12‐week study, 1414 adults accepted HIV testing. Of those, 463 (32.7%) were HIV‐infected. Seven hundred and twenty (50.9%) were surveyed. Compared with married women, unmarried men were at the highest risk of HIV [odds ratio (OR) 6.84; 95% confidence interval (CI) 3.45–23.55], followed by unmarried women (OR 5.90; 95% CI 3.25–10.70) and married men (OR 4.00; 95% CI 2.04–7.83). Age 30–39 years (compared with ≥50 years; OR 5.10; 95% CI 2.86–9.09), no prior HIV test (OR 1.45; 95% CI 1.07–2.27) and an imperfect HIV knowledge score (OR 2.32; 95% CI 1.24–4.35) were also associated with HIV infection.

Conclusion

In a routine HIV testing programme in South Africa, rates of previously undiagnosed HIV were highest among men, young and unmarried patients, and those with poorer HIV knowledge. Better interventions are needed to improve HIV knowledge and decrease HIV risk behaviour.     

Left ventricular remodelling in asymptomatic HIV infection on chronic HAART: comparison between hypertensive and normotensive subjects with and without HIV infection

The high cardiovascular risk of HIV infected (HIV+) patients is still partly unexplained. We aimed to evaluate if HIV infection and highly active antiretroviral therapy (HAART) are linked per se to left ventricular (LV) remodelling, independently of blood pressure (BP) values. We enrolled 4 groups of patients matched by gender, age, body mass index and smoking habit: 30 HIV+ hypertensives, 30 HIV+ normotensives, 30 not-infected (HIV-) hypertensives and 30 HIV- normotensives. HIV+ patients were on chronic HAART. Hypertension was newly diagnosed (≤6 months) and never treated. Each patient underwent blood tests, 24-h BP monitoring and LV echocardiogram. The 4 groups had similar fasting glucose and cholesterol; triglycerides, HOMA index and prevalence of metabolic syndrome were higher in the HIV+ groups. Despite similar 24-h BP values, HIV+ hypertensives had greater LV mass and higher prevalence of preclinical diastolic dysfunction than HIV- hypertensives. Compared to HIV- normotensives, HIV+ normotensives had similar 24-h BP values, but greater LV mass and lower LV diastolic indices, similar to HIV- hypertensives, whose 24-h BP values were higher. Asymptomatic HIV infection and chronic HAART are associated with myocardial hypertrophy and preclinical diastolic dysfunction, independently of BP values.     

Cognitive dysfunction in HIV encephalitic SCID mice correlates with levels of Interferon-alpha in the brain

BACKGROUND: Interferon alpha (IFNalpha) is an antiviral cytokine produced in response to viral infection. IFNalpha also acts as a neuromodulatory molecule in the central nervous system (CNS). Elevated IFNalpha in the CNS causes cognitive deficits. OBJECTIVE: To determine if elevated levels of IFNalpha in an HIV encephalitis mouse model correlate with cognitive deficits. METHODS: C57BL/6J SCID mice were inoculated intracerebrally (i.c.) with HIV infected or uninfected (control) macrophages and cognitively tested in a water escape radial arm maze. After behavioral testing was completed, immunohistochemistry and ELISA were used to examine brain pathology and IFNalpha expression. RESULTS: Mice injected i.c. with HIV infected macrophages exhibited significantly more working memory errors, particularly in trials with the highest memory load. Immunohistochemistry indicated increased mouse IFNalpha staining prevalent on neurons and glial cells in the brains of mice with HIV infected macrophages compared to mice with uninfected control macrophages. In addition, IFNalpha levels in the brain correlated directly with working memory errors for mice with HIV infected macrophages. CONCLUSIONS: These data suggest that the cognitive deficit noted for the C57BL/6J SCID mice with HIV infected macrophages is mediated by the infection induced increase in IFNalpha.     

Genetic correlates of protection against HIV infection: the ally within

Repeated exposure to HIV does not necessarily result in infection and HIV infection does not inevitably lead to the development of the AIDS. Multiple immunological and genetic features can confer resistance to HIV acquisition and progression at different steps in viral infection; a full understanding of these mechanisms could result in the development of novel therapeutic and vaccine approaches for HIV infection. In this review, we focus on the genetic mechanisms associated with resistance to HIV infection and to the progression to AIDS.