Three dimensional evaluation of cerebrovascular density and branching in chronic traumatic encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with exposure to repetitive head impacts (RHI) and characterized by perivascular accumulations of hyperphosphorylated tau protein (p-tau) at the depths of the cortical sulci. Studies of living athletes exposed to RHI, including concussive and nonconcussive impacts, have shown increased blood-brain barrier permeability, reduced cerebral blood flow, and alterations in vasoreactivity. Blood-brain barrier abnormalities have also been reported in individuals neuropathologically diagnosed with CTE. To further investigate the three-dimensional microvascular changes in individuals diagnosed with CTE and controls, we used SHIELD tissue processing and passive delipidation to optically clear and label blocks of postmortem human dorsolateral frontal cortex. We used fluorescent confocal microscopy to quantitate vascular branch density and fraction volume. We compared the findings in 41 male brain donors, age at death 31-89 years, mean age 64 years, including 12 donors with low CTE (McKee stage I-II), 13 with high CTE (McKee stage III-IV) to 16 age- and sex-matched non-CTE controls (7 with RHI exposure and 9 with no RHI exposure). The density of vessel branches in the gray matter sulcus was significantly greater in CTE cases than in controls. The ratios of sulcus versus gyrus vessel branch density and fraction volume were also greater in CTE than in controls and significantly above one for the CTE group. Hyperphosphorylated tau pathology density correlated with gray matter sulcus fraction volume. These findings point towards increased vascular coverage and branching in the dorsolateral frontal cortex (DLF) sulci in CTE, that correlates with p-tau pathology.

Vascular injury is associated with repetitive head impacts and tau pathology in chronic traumatic encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease linked to repetitive head impacts (RHI) and characterized by perivascular hyperphosphorylated tau (p-tau) deposits. The role of vascular injury, blood-brain barrier leakage, and neuroinflammation in CTE pathogenesis is not well understood. We performed quantitative immunoassays for intercellular adhesion molecule 1 (ICAM1), vascular cellular adhesion molecule 1 (VCAM1), and C-reactive protein (CRP) within the postmortem dorsolateral frontal cortex of participants with and without a history of RHI and CTE (n = 156), and tested for associations with RHI, microgliosis, and tau pathology measures. Levels of vascular injury-associated markers ICAM1, VCAM1, and CRP were increased in CTE compared to RHI-exposed and -naïve controls. ICAM1 and CRP increased with RHI exposure duration (p < 0.01) and were associated with increased microglial density (p < 0.001) and tau pathology (AT8, p-tau396, p-tau202; p < 0.05). Histologically, there was significantly increased ICAM1 staining of the microvasculature, extracellular space, and astrocytes at the sulcal depths in high stage CTE compared to both low stage CTE and controls. Multifocal perivascular immunoreactivity for serum albumin was present in all RHI-exposed individuals. These findings demonstrate that vascular injury markers are associated with RHI exposure, duration, and microgliosis, are elevated in CTE, and increase with disease severity.

Tau phosphorylation sites serine202 and serine396 are differently altered in chronic traumatic encephalopathy and Alzheimer's disease

INTRODUCTION

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive head impacts (RHI) typically sustained by contact sport athletes. Post-translation modifications to tau in CTE have not been well delineated or compared to Alzheimer's disease (AD).

METHODS

We measured phosphorylated tau epitopes within dorsolateral frontal cortex from post mortem brains with neither CTE nor AD (n = 108), CTE (n = 109), AD (n = 223), and both CTE and AD (n = 33).

RESULTS

Levels of hyperphosphorylated tau (p-tau)202 , p-tau231 , and p-tau396 were significantly increased in CTE. Total years of RHI exposure was significantly associated with increased p-tau202 levels (P = .001), but not p-tau396 . Instead, p-tau396 was most closely related to amyloid beta (Aβ)1-42 levels (P < .001). The p-tau202 :p-tau396 ratio was significantly increased in early and late CTE compared to AD.

DISCUSSION

In frontal cortex, p-tau202 is the most upregulated p-tau species in CTE, while p-tau396 is most increased in AD. p-tau202 and p-tau396 measurements may aid in developing biomarkers for disease.

CCL2 is associated with microglia and macrophage recruitment in chronic traumatic encephalopathy

Background

Neuroinflammation has been implicated in the pathogenesis of chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease association with exposure to repetitive head impacts (RHI) received though playing contact sports such as American football. Past work has implicated early and sustained activation of microglia as a potential driver of tau pathology within the frontal cortex in CTE. However, the RHI induced signals required to recruit microglia to areas of damage and pathology are unknown.

Methods

Postmortem brain tissue was obtained from 261 individuals across multiple brain banks. Comparisons were made using cases with CTE, cases with Alzheimer’s disease (AD), and cases with no neurodegenerative disease and lacked exposure to RHI (controls). Recruitment of Iba1+ cells around the CTE perivascular lesion was compared to non-lesion vessels. TMEM119 staining was used to characterize microglia or macrophage involvement. The potent chemoattractant CCL2 was analyzed using frozen tissue from the dorsolateral frontal cortex (DLFC) and the calcarine cortex. Finally, the amounts of hyperphosphorylated tau (pTau) and Aβ₄₂ were compared to CCL2 levels to examine possible mechanistic pathways.

Results

An increase in Iba1+ cells was found around blood vessels with perivascular tau pathology compared to non-affected vessels in individuals with RHI. TMEM119 staining revealed the majority of the Iba1+ cells were microglia. CCL2 protein levels in the DLFC were found to correlate with greater years of playing American football, the density of Iba1+ cells, the density of CD68+ cells, and increased CTE severity. When comparing across multiple brain regions, CCL2 increases were more pronounced in the DLFC than the calcarine cortex in cases with RHI but not in AD. When examining the individual contribution of pathogenic proteins to CCL2 changes, pTau correlated with CCL2, independent of age at death and Aβ₄₂ in AD and CTE. Although levels of Aβ₄₂ were not correlated with CCL2 in cases with CTE, in males in the AD group, Aβ₄₂ trended toward an inverse relationship with CCL2 suggesting possible gender associations.

Conclusion

Overall, CCL2 is implicated in the pathways recruiting microglia and the development of pTau pathology after exposure to RHI, and may represent a future therapeutic target in CTE.

Putative dendritic correlates of chronic traumatic encephalopathy: A preliminary quantitative Golgi exploration

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder that is associated with repetitive head impacts. Neuropathologically, it is defined by the presence of perivascular hyperphosphorylated tau aggregates in cortical tissue (McKee et al., 2016, Acta Neuropathologica, 131, 75-86). Although many pathological and assumed clinical correlates of CTE have been well characterized, its effects on cortical dendritic arbors are still unknown. Here, we quantified dendrites and dendritic spines of supragranular pyramidal neurons in tissue from human frontal and occipital lobes, in 11 cases with (M_age = 79 ± 7 years) and 5 cases without (M_age = 76 ± 11 years) CTE. Tissue was stained with a modified rapid Golgi technique. Dendritic systems of 20 neurons per region in each brain (N = 640 neurons) were quantified using computer-assisted morphometry. One key finding was that CTE neurons exhibited increased variability and distributional changes across six of the eight dendritic system measures, presumably due to ongoing degeneration and compensatory reorganization of dendritic systems. However, despite heightened variation among CTE neurons, CTE cases exhibited lower mean values than Control cases in seven of the eight dendritic system measures. These dendritic alterations may represent a new pathological marker of CTE, and further examination of dendritic changes could contribute to both mechanistic and functional understandings of the disease.

Randomized trial of a "talking computer" to improve adults' eating habits

PURPOSE

To assess efficacy of an intervention delivered by an interactive, computer-controlled telephone system to improve individuals' diets.

DESIGN

Randomized controlled trial.

SETTING

Large multispecialty group practice.

SUBJECTS

Two hundred ninety-eight adults who were both sedentary and had suboptimal diet quality.

INTERVENTION

Weekly communication for 6 months via a totally automated, computer-based voice system. Among intervention group subjects, the system monitored dietary habits and provided educational feedback, advice, and behavioral counseling. Control group subjects received physical activity promotion counseling.

MEASURES

Daily intake of fruits, vegetables, red and processed meats, whole fat dairy foods, and whole grain foods estimated from a food frequency questionnaire.

RESULTS

Mean age 45.9 years, 72% women, 45% white, and 45% African-American. Among participants who completed diet assessments, compared with the control group, the intervention raised fruit intake a mean of 1.1 servings per day (95% confidence interval [CI] .4, 1.7). On a 0 to 100 global diet quality score combining all five food groups, intervention participants improved their mean score 9 (95% CI 4, 13) points more than in the control group. The intervention also raised dietary fiber intake 4.0 g/d (95% CI .1, 7.8) and decreased saturated fat, as a proportion of energy intake, by 1.7% (95% CI -2.7, -.7).

CONCLUSIONS

This computer-based telecommunications dietary behavior intervention helped improve participants' overall diet.

Bronchiolitis obliterans organizing pneumonia mimicking multiple pulmonary metastases

A 45-year-old woman with no history of cancer presented with a radiological and clinical diagnosis of metastatic tumor in the lungs. On the basis of the findings, the patient underwent an extensive investigation attempting to locate a primary tumor. After an unsuccessful workup, the patient was referred for biopsy, which showed findings of bronchiolitis obliterans organizing pneumonia (BOOP). This case illustrates that the clinical, roentgenographic, and CT findings of BOOP are nonspecific and in some cases can be confused with those of metastatic tumor in the lungs.

cGMP is decreased after acute ischemia in chronically ischemic canine limbs

BACKGROUND

A chronic partially ischemic state may alter the skeletal muscle response to acute ischemia and free radical formation.

METHODS

In order to investigate this hypothesis, a chronic ischemic state was established by ligating the right femoral artery of four mongrel dogs. ABIs were decreased from 1.05 +/- 0.25 preligation to 0.54 +/- 0.14 at 6 weeks (P = 0.04). At the end of 8 weeks, the hindlimb was subjected to 3 h of acute ischemia by clamping the iliac artery. The clamp was then released for 2 h of reperfusion. Plasma samples from the right iliac vein were taken during the ischemia-reperfusion period for analysis of cGMP. Tibialis anterior biopsies for Western analysis of eNOS and iNOS were taken upon completion of reperfusion. Comparisons to control dogs subjected to the acute ischemia and reperfusion without prior femoral artery ligation were made.

RESULTS

cGMP levels were increased in the controls at 3 h of ischemia (3539 +/- 350) and 2 h of reperfusion (2880 +/- 269). The chronic ischemia group did not develop a corresponding increase in cGMP at 3 h of ischemia (2762 +/- 251) or after 2 h of reperfusion (2102 +/- 130). Western analysis of eNOS and iNOS revealed similar levels in both groups. Analysis of eNOS revealed 0.6429 +/- 0.086 and 0.5916 +/- 0.072 (densitometric units +/- SEM) for study and control dogs, respectively. Analysis of iNOS revealed 0.3401 +/- 0.067 and 0.2475 +/- 0.066 for study and control dogs, respectively.

CONCLUSION

Previous ligation of the femoral artery resulting in chronic partial ischemia in this model demonstrated no increase in cGMP following acute ischemia that was not accompanied by a change in eNOS or iNOS levels. Nitric oxide activity is reflected by cGMP levels, which may increase in response to free radicals in the acute setting of complete ischemia.

Dendritic cell-T-cell interactions support coreceptor-independent human immunodeficiency virus type 1 transmission in the human genital tract

Worldwide, human immunodeficiency virus (HIV) is transmitted predominantly by heterosexual contact. Here, we investigate for the first time, by examining mononuclear cells obtained from cervicovaginal tissue, the mechanisms whereby HIV type 1 (HIV-1) directly targets cells from the human genital tract. In contrast to earlier findings in mucosal models such as human skin, we demonstrate that the majority of T cells and macrophages but none or few dendritic cells (DC) express the HIV-1 coreceptor CCR5 in normal human cervicovaginal mucosa, whereas all three cell types express the coreceptor CXCR4. To understand the role of coreceptor expression on infectivity, mucosal mononuclear cells were infected with various HIV-1 isolates, using either CCR5 or CXCR4. Unstimulated T cells become rapidly, albeit nonproductively, infected with R5- and X4-tropic variants. However, DC and T cells form stable conjugates which permit productive infection by viruses of both coreceptor specificities. These results indicate that HIV-1 can exploit T-cell-DC synergism in the human genital tract to overcome potential coreceptor restrictions on DC and postentry blocks of viral replication in unactivated T cells. Thus, mononuclear cells infiltrating the genital mucosa are permissive for transmission of both R5- and X4-tropic HIV-1 variants, and selection of virus variants does not occur by differential expression of HIV-1 coreceptors on genital mononuclear cells.

Cellular immunity and target cell susceptibility in persons with repeated HIV-1 exposure

We prospectively studied 37 HIV-1 uninfected persons engaging in repeated high risk sexual activity with an HIV-1 infected partner, as well as 18 of their infected partners. Only one subject (3%) demonstrated the homozygous 32-bp deletion delta32delta32 of the HIV-1 co-receptor CCR5. CD4+ cells from all high risk subjects except the delta32delta32 CCR5 homozygote were susceptible in vitro to both CCR5-dependent and CXCR4-dependent HIV-1 strains. Median HIV-1 plasma RNA levels of the infected partners were not significantly different from levels of matched infected controls. Thirteen subjects demonstrated HIV-1 specific CTL at one or more visits, and these activities were more commonly observed in persons with the wild type CCR5 genotype. These results indicate that cellular immunity rather than inheritance of the delta32 CCR5 mutation accounts more often for persistently HIV-1-resistant cases.

Broadening the Tests of Learning Models

For many years psychological studies of the learning process have used a simulated medical diagnosis task in which symptom configurations are probabilistically related to diseases. Participants are given a set of symptoms and asked to indicate which disease is present, and feedback is given on each trial. We enrich this standard laboratory task in four different ways. First, the symptoms have four possible values (low, medium low, medium high, and high) rather than just two. Second, symptom configurations are generated from an expanded factorial design rather than a simple factorial design. Third, subjects are asked to make a continuous judgment indicating their confidence in the diagnosis, rather than simply a binary judgment. Fourth, cumulated performance scores, payoffs, and the availability of a historical summary of the outcomes are varied in order to assess how these treatments modulate performance. These enrichments provide a broader data set and more challenging tests of the models. Using 123 subjects each in 480 trials, we compare five existing learning models plus several variants, including the well-known Bayesian, fuzzy logic, connectionist, exemplar, and ALCOVE models. We find that the subjects do learn to distinguish the symptom configurations, that subjects are quite heterogeneous in their response to the task, and that only a small part of the variation across subjects arises from the differences in treatments. The most striking finding is that the model that best predicts subjects' behavior is a simple Bayesian model with a single fitted parameter for prior precision to capture individual differences. We use rolling regression techniques to elucidate the behavior of this model over time and find some evidence of over-response to current stimuli. Copyright 1998 Academic Press.

Perceptions of side effects following axillary block used for outpatient surgery

BACKGROUND AND OBJECTIVES

The study evaluated patient perceptions of side effects related to axillary block (AB) and how they might influence a patient's decisions about subsequent ABs.

METHODS

A questionnaire concerning the occurrence and duration of side effects following AB and patient preference for a subsequent AB was completed and returned by each of 1,149 patients. All ABs were performed using a 22 gauge short bevel needle. In all 86.5% had orthopedic surgery, with the remainder vascular access procedures. Three AB techniques and two anesthetic solutions were used.

RESULTS

Patient-reported incidences of side effects were bruising, 19.1%; soreness, 39.7%; persistent numbness, 11.0%; and nausea, 10.8%. Bruising was reported more frequently by female patients, those undergoing orthopedic procedures, and those between 20 and 30 and over 80 years of age. Soreness was reported more frequently in orthopedic procedures and by those aged 20 to 30. Technique used did not affect the incidence of side effects or patient willingness to have a repeat AB. Ninety-three percent expressed willingness to have another AB; this was affected by whether the patient experienced a side effect, the duration of the side effect, and by the number of side effects experienced. Those between the ages of 20 and 40 were less willing to have another AB.

CONCLUSIONS

Even though 51% of the patients reported at least one side effect, 93% would choose to have another AB, indicating a high overall satisfaction with AB anesthesia, which significantly decreased as the number and duration of side effects increased.

Farm-related injury fatalities in Oklahoma, 1987-1991

Farm-related injury is often cited as a major factor in rural health care. This is an attempt to obtain an estimate of the frequency of serious farm injuries in Oklahoma. It is apparent that current available data bases are not adequate to be definitive, but mortality data is available, albeit incomplete. One hundred thirty-two deaths were recorded on death certificates for 1987 through 1991, with falls accounting for nearly half. The other data are summarized, and a review of the farm injury literature is presented. In summary, it is clear that farm injuries are a significant problem and steps to prevent them are required.

Oncotic pressure, albumin and ileus: the effect of albumin replacement on postoperative ileus

The effect of decreased colloid oncotic pressure, as seen in hypoalbuminemia and hypoproteinemia, upon intestinal function has been well delineated in the surgical literature. Patients undergoing abdominal aortic aneurysm resection or aortoiliac or aortofemoral bypass grafts are almost uniformly hypoalbuminemic postoperatively; with these two facts in mind, a prospective, randomized clinical study was undertaken to identify the role of serum albumin concentration on the length of postoperative ileus in this population. The main hypothesis was that patients whose albumin levels dropped below 3.5 gm/dL would have a more prolonged postoperative hospital course as a result of delay in return of bowel function when compared with those patients in whom the low albumin levels were exogenously acutely replenished to > 3.5 gm/dL. Albumin was replaced to a level greater-than or equal to 3.5 g/dL in one group of 37 patients (AR), with a control group of 32 patients (NR) not receiving any albumin. Return of bowel function was measured by the postoperative day that flatus was documented, as well as the postoperative day oral intake was resumed. Mean values were determined for each group, and t tests did not reveal a significant difference in postoperative day of flatus (AR mean = 4.06 days, NR mean = 4.16 days) or postoperative day of oral intake (AR mean = 4.0, NR mean = 3.75). Additional comparisons between the groups involving the number of postoperative days until a regular diet was begun (AR mean = 6.06, NR mean = 5.48) and length of postoperative hospital stay (AR mean = 9.16, NR mean = 8.43) failed to reveal significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Should the Cell Saver Autotransfusion Device be used routinely in all infrarenal abdominal aortic bypass operations?

PURPOSE

The purpose of this study was to attempt to identify a group of patients undergoing infrarenal aortic bypass in whom blood loss is consistently less than 2 units, making the routine use of autotransfusion devices unnecessary.

METHODS

Four groups of patients were prospectively studied as follows: abdominal aortic aneurysm (AAA) repair with tube graft (n = 21), AAA repair with bifemoral or biiliac bypass (n = 19), and aortobifemoral bypass (AFB) or biiliac bypass for occlusive disease either with Cell Saver Autotransfusion Device (Haemonetics Corp., Braintree, Mass.) (n = 18) or without Cell Saver (n = 18). The latter two groups were randomized on an alternating basis.

RESULTS

The following parameters were obtained on all patients: preoperative hemoglobin values, estimated blood loss, Cell Saver return volumes, intraoperative and postoperative homologous blood transfused, postoperative hemoglobin values on the day of surgery and on postoperative days 1 and 4, complications, and length of hospital stay. In comparing the groups undergoing AFB with Cell Saver and AFB without Cell Saver by the above parameters, we found no statistically significant differences, except for a higher hemoglobin level on postoperative day 1 in the group undergoing AFB with Cell Saver (mean 11.86 vs 10.74, p = 0.02). The estimated blood loss and Cell Saver return volumes were less for those patients undergoing AFB for occlusive disease compared with those undergoing AFB for aneurysmal disease. Interestingly, estimated blood loss and Cell Saver return volumes for patients with AAA with tube graft and patients undergoing AFB with Cell Saver were similar.

CONCLUSIONS

We conclude that routine setup and use of rapid autotransfusion devices may not be necessary in every patient undergoing routine aortofemoral bypass for occlusive disease. Furthermore, the possibility that some patients may undergo AAA repair with tube grafts without use of the Cell Saver may be deserving of further investigation.

Foreign body reactions secondary to cellulose lint fibers

Twenty-four cases of foreign body reactions secondary to cellulose lint fibers have been identified in three Portland area hospitals over a 5 year period. Ten of these cases involved extraperitoneal granuloma and 14 cases intraperitoneal granuloma. Six of the intraperitoneal reactions resulted in acute granulomatous peritonitis, and one of these patients died from this complication. Twenty-two additional operations were performed on these patients because of complications directly associated with this reaction. As estimated 400 days of additional hospitalization were required secondary to complications of foreign body reaction. Several precautionary measures have been identified that have decreased the incidence of this complication in our hospitals. Polypropylene drapes and gowns may provide a solution to this problem in the future.