Sevoflurane exerts antidepressant-like effects via the BDNF-TrkB pathway

Depression has emerged as the predominant psychiatric affliction affecting individuals. Prior research has substantiated the antidepressant properties exhibited by numerous anesthetics. Sevoflurane, a widely utilized inhalant anesthetic in clinical practice, remains relatively uncharted in terms of its specific antidepressant effects. In this study, we used open field test, forced swimming test and novelty-suppressed feeding test to investigate the anxiety and depression-like behaviors in C57BL/6 mice following the inhalation of sevoflurane. We then used western blotting to scrutinized the expression levels of proteins associated with the brain-derived neurotrophic factor (BDNF)-tryosine receptor kinase B (TrkB) pathway in the hippocampus and prefrontal cortex. To further investigate whether sevoflurane exerts antidepressant-like effects via the BDNF-TrkB pathway, we downregulated TrkB expression by administering siRNA into the lateral ventricle. We found that the inhalation of 2.5 % sevoflurane exerted a significant antidepressant-like effect, accompanied by an elevation in p-TrkB expression levels in the hippocampus and prefrontal cortex. Intriguingly, this antidepressant-like effect was abrogated following the downregulation of TrkB expression through the microinjection of siRNA into the lateral ventricle. In conclusion, this study provides evidence supporting the notion that sevoflurane exerts its antidepressant-like effect via the BDNF-TrkB signaling pathway.

[Clinical effect of superior oblique re-tucking for recurrent or residual compensatory head position]

Objective: To evaluate the effects of re-tucking the superior oblique muscle on recurrent or residual compensatory head position. Methods: A retrospective case series study was conducted. 12 recurrent or residual compensatory head position patients (12 eyes) with congenital superior oblique palsy who underwent superior oblique re-tucking in Tianjin Eye Hospital from March 2015 to February 2021 were included. All patients had a history of superior oblique tucking procedure and showed signs of superior oblique muscle palsy without inferior oblique muscle overaction. During surgery, the Guyton forced duction test is used to evaluate the relaxation of the superior oblique muscle tendon, which affects the re-tucking length of the muscle.Their head position, vertical deviation, eye movement, fovea-disa angle, and Bielschowsky head tilt test were assessed pre-and post-surgery. Statistical analysis was performed using ttest and paired samples Wilcoxon signed rank test. Results: Out of the 12 patients, 8 were male and 4 were female, aged between 2 and 9 years. The initial surgery was done at age 6, with a superior oblique recession length of (7.17±1.03) mm. Recurrent head tilt occurred in 11 patients after (3.82±0.98) months postoperatively, and 1 patient had residual head tilt, with a followup period of six months or more. Ocular motility examination revealed underaction of the superior oblique muscle, positive Bielschowsky's head tilt test, and Guyton forced duction tese indicating relaxation of the paralyzed superior oblique muscle tendon. Scar adhesion was observed at the stop of the superior oblique muscle, as well as the previous sutures. The scar and the sutures around the stop of the superior oblique muscle were released, the mean re-tucking amount was(7.83±1.59)mm. Follow-up at 12 to 18 months postoperatively showed disappearance of compensatory head position, significant improvement in superior oblique muscle lag, normal ocular motility, and no occurrence of Brown syndrome. The results of Bielschowsky head tilt were negative in 9 cases and still positive in 3 cases after superior oblique re-tucking. The primary vertical deviation was 2.5 (2.0, 5.3) prism diopter pre-operatively and 1 (0, 1) prism diopter post-operatively, respectively. The difference was statistically significant (U=6.00, P<0.001). The total amount of FDA in both eyes was (-22.04±5.47)° and (-15.27±6.08)° pre-and post-operatively, respectively. The difference was statistically significant (t=2.87, P=0.009). All 12 patients have normal eye movement after superior oblique re-tucking procedure. All patients had no compensatory head position at last follow-up. Conclusions: Superior oblique re-tucking is suitable for patients with relaxation of the superior oblique muscle tendon and extrocular rotation as the main sign. It can effectively and safely correct the recurrent or residual compensatory head position after re-tucking the superior oblique muscle.

The value of pupillary diameter in evaluating pain perception after awakening in patients undergoing general anesthesia during orthopedic surgery

BACKGROUND

The pupillary response to tetanic electrical stimulation reflects the balance between nociceptive stimulation and analgesia. Although pupillary pain index (PPI) was utilized to predict postoperative pain, it depended on tetanic stimulation and was complex. We aim to describe the potential relationship between PD in the presence of surgical stimulation and pain levels after awakening.

METHODS

According to the Verbal Rating Scale (VRS) score after extubation, the patients were divided into painless group (VRS = 0) and pain group (VRS ≥ 1). Pupillary diameter (PD) and pupillary light reflex velocity (PLRV) were compared between two groups when patients entered the operating room (T1), before incision (T2), 10 s after incision (T3), 30 s after incision (T4), 1 h after incision (T5), at the end of surgery (T6), shortly after extubation (T7), and when patients expressed pain clearly (T8). The magnitude of PD change (ΔPD) compared to the baseline value after anesthesia induction (T2) was calculated. The correlations between pupillary parameters and pain after awakening were calculated.

RESULTS

Patients with VRS ≥ 1 had greater PD than painless patients at T3-7 (P = 0.04, 0.04, 0.003, <0.001, <0.001), and it was positively correlated with VRS score after awakening at T4-7 (r = 0.188, 0.217, 0.684, 0.721). The ability of T6ΔPD to predict VRS ≥ 1 was strong [threshold: 20.53%, area under the curve (AUC): 0.93, 95% confidence interval (CI): 0.89-0.97 ].

CONCLUSION

Our study indicates that PD is a useful index to direct the individualized analgesics used during operation, to better avoid the occurrence of pain during the postoperative emergence period.

TRIAL REGISTRATION

This study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2000040908, registration date: 15/12/2020).

The modified lymphocyte C-reactive protein score is a promising indicator for predicting 3-year mortality in elderly patients with intertrochanteric fractures

BACKGROUND

Hip fractures are common in elderly patients, and almost all the patients undergo surgery. This study aimed to develop a novel modified lymphocyte C-reactive protein (CRP) score (mLCS) to simply and conveniently predict 3-year mortality in elderly patients undergoing intertrochanteric fracture surgery.

METHODS

A retrospective study was conducted on elderly patients who underwent intertrochanteric fracture surgery between January 2014 and December 2017. The mLCS was developed according to the value of CRP and lymphocyte counts. Univariate and multivariate Cox regression analyses were used to identify independent risk factors for 3-year mortality after surgery. The performances of the lymphocyte CRP score (LCS) and mLCS to predict 3-year mortality were then compared using C-statistics, decision curve analysis (DCA), net reclassification index (NRI) and integrated discrimination improvement (IDI).

RESULTS

A total of 291 patients were enrolled, of whom 52 (17.9%) died within 3 years after surgery. In the multivariate Cox regression analysis, mLCS (hazard ratio (HR), 5.415; 95% confidence interval (CI), 1.743-16.822; P = 0.003) was significantly associated with postoperative 3-year mortality. The C-statistics of LCS and mLCS for predicting 3-year mortality were 0.644 and 0.686, respectively. The NRI (mLCS vs. LCS, 0.018) and IDI (mLCS vs. LCS, 0.017) indicated that the mLCS performed better than the LCS. DCA also showed that mLCS had a higher clinical net benefit.

CONCLUSIONS

mLCS is a promising predictor that can simply and conveniently predict 3-year mortality in elderly patients undergoing intertrochanteric fracture surgery.

Therapeutic effects of mesenchymal stem cells and their derivatives in common skin inflammatory diseases: Atopic dermatitis and psoriasis

Chronic skin inflammatory diseases including atopic dermatitis (AD) and psoriasis have been considered uncontrolled inflammatory responses, which have usually troubled patients around the world. Moreover, the recent method to treat AD and psoriasis has been based on the inhibition, not regulation, of the abnormal inflammatory response, which can induce a number of side effects and drug resistance in long-term treatment. Mesenchymal stem/stromal cells (MSCs) and their derivatives have been widely used in immune diseases based on their regeneration, differentiation, and immunomodulation with few adverse effects, which makes MSCs a promising treatment for chronic skin inflammatory diseases. As a result, in this review, we aim to systematically discuss the therapeutic effects of various resources of MSCs, the application of preconditioning MSCs and engineering extracellular vesicles (EVs) in AD and psoriasis, and the clinical evaluation of the administration of MSCs and their derivatives, which can provide a comprehensive vision for the application of MSCs and their derivatives in future research and clinical treatment.

New insight into neurological degeneration: Inflammatory cytokines and blood–brain barrier

Neurological degeneration after neuroinflammation, such as that resulting from Alzheimer’s disease (AD), stroke, multiple sclerosis (MS), and post-traumatic brain injury (TBI), is typically associated with high mortality and morbidity and with permanent cognitive dysfunction, which places a heavy economic burden on families and society. Diagnosing and curing these diseases in their early stages remains a challenge for clinical investigation and treatment. Recent insight into the onset and progression of these diseases highlights the permeability of the blood–brain barrier (BBB). The primary factor that influences BBB structure and function is inflammation, especially the main cytokines including IL-1β, TNFα, and IL-6, the mechanism on the disruption of which are critical component of the aforementioned diseases. Surprisingly, the main cytokines from systematic inflammation can also induce as much worse as from neurological diseases or injuries do. In this review, we will therefore discuss the physiological structure of BBB, the main cytokines including IL-1β, TNFα, IL-6, and their mechanism on the disruption of BBB and recent research about the main cytokines from systematic inflammation inducing the disruption of BBB and cognitive impairment, and we will eventually discuss the need to prevent the disruption of BBB.

Epidemiology and clinical characteristics of burns in mainland China from 2009 to 2018

Background

Burn injuries place a heavy burden on the global healthcare system. However, there is still a lack of nationwide studies on the epidemiological characteristics of burn patients in mainland China. The present study aims to accurately analyze the clinical characteristics of burn patients by collecting data in mainland China from 2009 to 2018, which will provide effective strategies for healthcare systems and the government in mainland China.

Methods

Patients admitted for burn injuries to 196 hospitals in 31 provinces, autonomous regions and municipalities in mainland China from 2009 to 2018 were included. The data collected included sex, age, month distribution, etiology, region, clinical outcome, injury anatomical location, total burn surface area and mortality. SPSS 19.0 software was used to analyze the data.

Results

From 2009 to 2018, the burn patients were 333,995 (0.76%), which included 222,480 (66.61%) males and 111,515 (33.39%) females. From 2009 to 2018, the number of individuals admitted to hospitals for burns showed a downward trend year by year. The burn patients accounted for the highest proportion of inpatients in 0–10 years (38.10%), followed by 40–50 years (13.14%). The highest cure ratio of burn inpatients was in the 20–30 age group (31 394, 71.53%). Among 31 provinces, autonomous regions and municipalities, the province with the highest proportion of total inpatients caused by burns was Inner Mongolia (4.61%), followed by Zhejiang (3.17%), Hainan (2.88%) and Xinjiang (2.64%). Summer (29.16%) was the season with the highest incidence of burn patients admitted to hospitals, followed by spring (25.6%). Scalding (60.19%) was the most frequent kind of burn treated, followed by fire (20.45%). The patients had multiple burn sites (68.89%) most often, followed by burns on the lower limbs (10.91%). From 0% to 10% total body surface area (TBSA) accounted for the highest ratio (37.19%), followed by 90–100% TBSA (21.74%).

Conclusions

The present study is the first to describe the associated situation and trends of burn patients in mainland China from 2009 to 2018. Our findings will serve as the latest clinical evidence for healthcare planning and prevention efforts in China and other countries.

Dorsal raphe serotonergic neurons promote arousal from isoflurane anesthesia

Aims

General anesthesia has been widely applied in surgical or nonsurgical medical procedures, but the mechanism behind remains elusive. Because of shared neural circuits of sleep and anesthesia, whether serotonergic system, which is highly implicated in modulation of sleep and wakefulness, regulates general anesthesia as well is worth investigating.

Methods

Immunostaining and fiber photometry were used to assess the neuronal activities. Electroencephalography spectra and burst‐suppression ratio (BSR) were used to measure anesthetic depth and loss or recovery of righting reflex to indicate the induction or emergence time of general anesthesia. Regulation of serotonergic system was achieved through optogenetic, chemogenetic, or pharmacological methods.

Results

We found that both Fos expression and calcium activity were significantly decreased during general anesthesia. Activation of 5‐HT neurons in the dorsal raphe nucleus (DRN) decreased the depth of anesthesia and facilitated the emergence from anesthesia, and inhibition deepened the anesthesia and prolonged the emergence time. Furthermore, agonism or antagonism of 5‐HT 1A or 2C receptors mimicked the effect of manipulating DRN serotonergic neurons.

Conclusion

Our results demonstrate that 5‐HT neurons in the DRN play a regulative role of general anesthesia, and activation of serotonergic neurons could facilitate emergence from general anesthesia partly through 5‐HT 1A and 2C receptors.

Cell-type-specific imaging of neurotransmission reveals a disrupted excitatory-inhibitory cortical network in isoflurane anaesthesia

BACKGROUND

Despite the fundamental clinical significance of general anaesthesia, the cortical mechanism underlying anaesthetic-induced loss of consciousness (aLOC) remains elusive.

METHODS

Here, we measured the dynamics of two major cortical neurotransmitters, gamma-aminobutyric acid (GABA) and glutamate, through in vivo two-photon imaging and genetically encoded neurotransmitter sensors in a cell type-specific manner in the primary visual (V1) cortex.

FINDINGS

We found a general decrease in cortical GABA transmission during aLOC. However, the glutamate transmission varies among different cortical cell types, where in it is almost preserved on pyramidal cells and is significantly reduced on inhibitory interneurons. Cortical interneurons expressing vasoactive intestinal peptide (VIP) and parvalbumin (PV) specialize in disinhibitory and inhibitory effects, respectively. During aLOC, VIP neuronal activity was delayed, and PV neuronal activity was dramatically inhibited and highly synchronized.

INTERPRETATION

These data reveal that aLOC resembles a cortical state with a disrupted excitatory-inhibitory network and suggest that a functional inhibitory network is indispensable in the maintenance of consciousness.

FUNDING

This work was supported by the grants of the National Natural Science Foundation of China (grant nos. 81620108012 and 82030038 to H.D. and grant nos. 31922029, 61890951, and 61890950 to J.H.).

Selective optogenetic activation of orexinergic terminals in the basal forebrain and locus coeruleus promotes emergence from isoflurane anaesthesia in rats

BACKGROUND

The neuropeptide orexin promotes arousal from general anaesthesia, however the neuronal circuits that mediate this effect have not been defined. We investigated whether orexinergic neurones modulate the basal forebrain (BF) and locus coeruleus (LC) in emergence from anaesthesia.

METHODS

Hcrt^cre rats were generated using a CRISPR/Cas9-based approach. Viruses encoding optogenetic probes were injected into the perifornical lateral hypothalamic (PeFLH) area, optogenetic fibres were embedded in the PeFLH, BF, or LC, and changes in anaesthesia state under 1.4 vol% or 0.8 vol% isoflurane were determined.

RESULTS

In the PeFLH, 98.8% (0.4%) of orexin-A-positive cells expressed tdTomato, and 91.9% (2.2%) of tdTomato cells were orexin-A-positive. Under 1.4 vol% isoflurane anaesthesia, compared with control groups, burst suppression ratio was less, and emergence time was shorter in groups with optogenetic activation of orexinergic cell bodies in the PeFLH (923 [162] vs 493 [68] s, P=0.0003) or orexinergic terminals in the BF (937 (122) vs 674 (108) s, P=0.0049) or LC (913 [128] vs 742 [76] s, P=0.022). Optical stimulation of orexinergic terminals in the BF and LC also improved the movement scores of rats under 0.8 vol% isoflurane anaesthesia.

CONCLUSIONS

Activation of orexinergic terminals in the FB or LC mediates facilitation of emergence from anaesthesia by orexinergic neurones during isoflurane anaesthesia.

Serotonergic neurons in the dorsal raphe nucleus mediate the arousal-promoting effect of orexin during isoflurane anesthesia in male rats

Previous studies have demonstrated that the activation of orexinergic neurons facilitates the recovery of animals from general anesthesia. Moreover, serotonergic neurons that receive projections from orexin neurons have also been shown to participate in sleep-wakefulness regulation. In the present study, we aimed to explore whether orexinergic neurons facilitate emergence from isoflurane anesthesia in rats by activating serotonergic neurons. Orexin A (30 or 100 pmol), orexin B (30 or 100 pmol), and their respective antagonists SB-334867 and TCS-OX2-29 (5 or 20 μg) were microinjected into the dorsal raphe nucleus (DRN) of rats, and their effects on induction and emergence times were analyzed. Electroencephalogram (EEG) changes were also recorded and analyzed to illuminate the effect of orexin injection into the DRN on cortical excitability under isoflurane anesthesia. Activation of serotonergic neurons was detected via immunohistochemical analysis of c-Fos expression following orexin administration. Our results indicated that injection of neither orexins nor orexin antagonists into the rat DRN exerted an impact on induction time, whereas orexin-A injection (100 pmol) enhanced arousal when compared with the saline group. In contrast, administration of orexin receptor type 1 antagonist SB-334867 (20 μg) prolonged emergence time from isoflurane anesthesia. Microinjection of orexin-A induced an arousal pattern on EEG, and decreased the burst suppression ratio under isoflurane anesthesia. Isoflurane anesthesia inhibited the activity of serotonergic neurons, as shown by decrease in the number of c-Fos-immunoreactive serotonergic neurons when compared with the sham group. This inhibitory effect was partially reversed by administration of orexin-A. Taken together, our findings suggest that orexinergic signals facilitate emergence from isoflurane anesthesia, at least partially, by reversing the effects of isoflurane on serotonergic neurons of the DRN.

miR-26a suppresses autophagy in swine Sertoli cells by targeting ULK2

A large number of microRNAs (miRNAs) have been detected from porcine testicular tissues thanks to the development of high-throughput sequencing technology. However, the regulatory roles of most identified miRNAs in swine testicular development or spermatogenesis are poorly understood. In our previous study, ULK2 (uncoordinated-51-like kinase 2) was predicted as a target gene of miR-26a. In this study, we aimed to investigate the role of miR-26a in swine Sertoli cell autophagy. The relative expression of miR-26a and ULK2 levels has a significant negative correlation (R²  = .5964, p ≤ .01) in nine developmental stages of swine testicular tissue. Dual-luciferase reporter assay results show that miR-26a directly targets the 3'UTR of the ULK2 gene (position 618-624). In addition, both the mRNA and protein expression of ULK2 were downregulated by miR-26a in swine Sertoli cells. These results indicate that miR-26a targets the ULK2 gene and downregulates its expression in swine Sertoli cells. Based on the expression of marker genes (LC3, p62 and Beclin-1), overexpression of miR-26a or knock-down of ULK2 inhibits swine Sertoli cell autophagy. Taken together, these findings demonstrate that miR-26a suppresses autophagy in swine Sertoli cells by targeting ULK2.

Circadian Rhythm Influences the Promoting Role of Pulsed Electromagnetic Fields on Sciatic Nerve Regeneration in Rats

Circadian rhythm (CR) plays a critical role in the treatment of several diseases. However, the role of CR in the treatment of peripheral nerve defects has not been studied. It is also known that the pulsed electromagnetic fields (PEMF) can provide a beneficial microenvironment to quicken the process of nerve regeneration and to enhance the quality of reconstruction. In this study, we evaluate the impact of CR on the promoting effect of PEMF on peripheral nerve regeneration in rats. We used the self-made “collagen-chitosan” nerve conduits to bridge the 15-mm nerve gaps in Sprague-Dawley rats. Our results show that PEMF stimulation at daytime (DPEMF) has most effective outcome on nerve regeneration and rats with DPEMF treatment achieve quickly functional recovery after 12 weeks. These findings indicate that CR is an important factor that determines the promoting effect of PEMF on peripheral nerve regeneration. PEMF exposure in the daytime enhances the functional recovery of rats. Our study provides a helpful guideline for the effective use of PEMF mediations experimentally and clinically.

Calorie restriction attenuates cerebral ischemic injury via increasing SIRT1 synthesis in the rat

Caloric restriction (CR) has been shown to have several health benefits and provides protection against type 2 diabetes, neurodegenerative and cerebral vascular diseases. It reduces the brain infarct size and promotes neurological functional recovery after cerebral ischemia. Sirtuin 1 (SIRT1) plays an important role in the biological effects induced by CR. This study investigated the role of SIRT1 in ischemic tolerance in the brain induced by CR. Sprague drawly rats were divided into two groups based on food intake. Ad libitum (AL) group was fed with normal diet while the CR group received 60% calories compared to AL. All animals were subjected to a middle cerebral artery occlusion for 90 min. Results showed the neurological function score of CR group was higher and the brain infarct volume was markedly reduced in CR group compared to AL group at 24h after reperfusion (p < 0.05). CR increased the synthesis of SIRT1 significantly (p < 0.05), and ameliorated the down regulation of SIRT1 expression at 6 and 12h after middle cerebral artery occlusion (p < 0.05, p < 0 .01, respectively). Knockdown of SIRT1 by siRNA in vivo reversed the neuroprotective effect of CR. From this study, we deduce that CR induces brain ischemic tolerance on rats via increasing the synthesis of SIRT1.

The Role of SUMO-Conjugating Enzyme Ubc9 in the Neuroprotection of Isoflurane Preconditioning Against Ischemic Neuronal Injury

Preconditioning with volatile anesthetics can create an ischemia tolerance against cerebral ischemia-reperfusion injury. We investigated whether ubiquitin conjugase 9 (Ubc9), the E2 conjugase for SUMOylation, is associated with neuroprotection induced by isoflurane preconditioning (IsoPC). In vitro, Ubc9 protein expression was evaluated at 4 and 24 h after reoxygenation. The role of Ubc9 in the neuroprotective effect was assessed in the presence or absence of Ubc9 small interfering RNA (siRNA). In vivo, rats were preconditionally exposed for 1 h to 2 % isoflurane for five consecutive days followed by middle cerebral artery occlusion. Neurobehavioral scores and infarction volume were determined at different times after reperfusion. The role of Ubc9 in ischemic tolerance was evaluated by intracerebroventricular microinjection with the Ubc9 siRNA. We showed that isoflurane preconditioning improved the cell viability of the SH-SY5Y cells that were challenged by oxygen-glucose deprivation. It also reduced brain infarct volumes and improved neurologic outcomes in the focal cerebral ischemic rat. The expression of Ubc9 was upregulated by isoflurane preconditioning. Knockdown of Ubc9 significantly attenuated the isoflurane preconditioning-induced neuroprotective effects. Isoflurane preconditioning-induced neuroprotection against ischemic injuries is mediated by Ubc9. These results suggest a novel mechanism for isoflurane preconditioning-induced tolerance to cerebral ischemia.

P01-297-Clinical characteristics of pediatric patients with bipolar disorders in china

Objective

To explore the clinical characteristics, assessment, biological and psychosocial correlates, and treatment of pediatric bipolar disorder (BD) in China.

Method

All the studies published during the past 20 years on pediatric bipolar disorder in China were reviewed.

Results

There is a lack of a unified diagnosis system in China. A serial of genetic researches showed the family aggregation and genetic predisposition of BD. There are consistent findings on the core symptoms of the disorder. BD has the characteristic of comorbidity with other disorders such as ADHD and OCD. Mood stabilizers and combined use of antipsychotics and TCA are still the main choice of psychiatrists to treat the pediatric patients with BD. The effectiveness of specific psychotherapy does need further studies.

Conclusion

A unified diagnosis system and criteria of BD for different age groups is crucial for further work. Combination of various treatments, such as mood stabilizers, AC, TCA and traditional Chinese medicine is effective for these patients. More studies, especially randomized controlled trials should be conducted to explore the etiology, pharmacotherapy and psychotherapy of this disease.

Natural course of schizophrenia: 2-year follow-up study in a rural Chinese community

BACKGROUND

A number of studies have questioned whether the natural course of schizophrenia is more favourable in "developing" than "developed" societies and whether culture is a factor in producing a favourable course.

AIMS

This prospective study tests the hypothesis that the natural outcome of schizophrenia would be favourable in a Chinese rural area.

METHOD

We investigated all patients with schizophrenia, including patients who had not received any treatment, among 149 231 rural community population in Xinjin County, Sichuan in 1994. Those patients who had never received treatment were followed up for two years.

RESULTS

Three-quarters of patients with schizophrenia who had not been treated remained symptomatic. As the duration of illness increased, the illness became more serious. The clinical outcome of the drug-treatment group was significantly better than for patients who had not received any treatment.

CONCLUSIONS

The natural clinical outcome of schizophrenia in the Chinese rural community was poor, and occupational functioning of patients with schizophrenia was comparatively better. Schizophrenia itself has a specific natural course--antipsychotic drug treatment and psychosocial treatment will produce an improvement in prognosis.

GCP-2-induced internalization of IL-8 receptors: hierarchical relationships between GCP-2 and other ELR(+)-CXC chemokines and mechanisms regulating CXCR2 internalization and recycling

The chemotactic potencies of ELR(+)-CXC chemokines during acute inflammation are regulated by their binding affinities and by their ability to activate, desensitize, and internalize their specific receptors, CXCR1 and CXCR2. To gain insight into the fine mechanisms that control acute inflammatory processes, we have focused in this study on the highly potent ELR(+)-CXC chemokine Granulocyte Chemotactic Protein 2 (GCP-2), and on its ability to control the cell surface expression of CXCR1 and CXCR2. Although GCP-2 has been considered an effective ligand for both CXCR1 and CXCR2, our findings demonstrated that it was a potent inducer of CXCR2 internalization only. A functional hierarchy was shown to exist between GCP-2 and 2 other ELR(+)-CXC chemokines, IL-8 and NAP-2, in their abilities to induce CXCR1 and CXCR2 internalization, according to the following: IL-8 > GCP-2 > NAP-2. By the use of pertussis toxin (PTx), it was demonstrated that the actual events of G(alphai)-coupling to CXCR2 do not have a major role in the regulation of its internalization. Rather, CXCR2 internalization was shown to be negatively controlled by induction of signaling events, as indicated by the promotion of CXCR2 internalization following exposure to wortmannin, a potent inhibitor of phosphatidylinositol (PI) 3 kinases and PI4 kinases. Furthermore, our results suggest that rab11(+)-endosomes participate in the trafficking of CXCR2 through the endocytic pathway, to eventually allow its recycling back to the plasma membrane. To conclude, our findings shed light on the interrelationships between GCP-2 and other ELR(+)-CXC chemokines, and determine the mechanisms involved in the regulation of GCP-2-induced internalization and recycling of CXCR2. (Blood. 2000;95:1551-1559)

Differential modes of regulation of cxc chemokine-induced internalization and recycling of human CXCR1 and CXCR2

Studies of human neutrophil IL-8 receptors, CXCR1 and CXCR2, have shown that the two receptors are differentially regulated by ELR(+)-CXC chemokines, that they differ functionally and may have diverse roles in mediating the inflammatory process. To elucidate the role of CXCR1 and CXCR2 in inflammation and to delineate the basis for the divergent regulation of these receptors by IL-8 and NAP-2, we characterized the IL-8- and NAP-2-induced mechanisms regulating the expression of each receptor, focusing on receptor internalization and recycling. Using HEK 293 cell transfectants, IL-8 was shown to induce significantly higher levels of CXCR2 internalization than NAP-2. Moreover, although CXCR2 bound IL-8 and NAP-2 with similarly high affinity, IL-8 functionally competed with and displaced NAP-2, and prompted high levels of internalization, similar to those induced by IL-8 alone. In a system providing an identical cellular milieu for reliable comparisons between CXCR1 and CXCR2, we have shown that the mechanisms controlling the internalization of CXCR1 diverge from those regulating CXCR2 internalization. Whereas IL-8-induced internalization of CXCR1 was profoundly dependent on a region of the carboxyl terminus expressing six phosphorylation sites, internalization of CXCR2 was primarily regulated by a membrane proximal domain of the carboxyl terminus that does not express phosphorylation sites. Analysis of receptor re-expression on the plasma membrane indicated that at early time points following removal of free ligand and incubation of the cells at 37 degrees C, receptor recycling accounted for recovery of CXCR1 and CXCR2 expression, whereas at later time points other processes may be involved in receptor re-expression. Phosphorylation-independent mechanisms were shown to direct both receptors to the recycling pathway. The differential control of CXCR1 vs CXCR2 internalization by IL-8 and NAP-2, as well as by phosphorylation-mediated mechanisms, suggests that a chemokine- and receptor-specific mode of regulation of internalization may contribute to the divergent activities of these receptors.

The in vivo enhancement of IL-1alpha receptor expression on polyoma virus transformed tumor derived cells

The aim of this study was to evaluate expression of receptor for IL-1 on tumor-derived cells. The in vivo acquisition of an expression of a receptor for Fc ç immunoglobulin on polyoma virus transformed cells has been established by us. We investigated whether a receptor for the IL-1 cytokine, like that for Fc gamma immunoglobulin, could also contribute to the heterogeneity of tumor cell population, as well as to its tumorigenic phenotype. Various clones of polyoma virus transformed 3T3 cells were passaged once in syngeneic mice and resulting tumors explanted and recultured. The expression of receptor for IL-1 was tested on in vitro maintained clones (designated C for culture) and on tumor derived clones (designated CTC - culture-tumor-culture). Expression was determined using a 125I radiolabeled ligand and confirmed by flow cytometry with anti-mouse IL-1 receptor (IL-1R) antibodies. Some CTC clones expressed a higher level of IL-1 receptor than others. A positive correlation between the level of IL-1R and a metastatic phenotype was established with some tumor derived cells. A high IL-1R expressing tumor cell population, sorted by flow cytometry, was considerably more metastatic than the sorted low IL-1 expressing cells. IL-1R expression by tumor derived cells may, contribute to the metastatic phenotype of a tumor cell population.

The tumorigenic phenotype of a mutated form of Fc gamma RIIB1, lacking the ability to generate soluble receptor and allowing a low-level of ligand binding

Non immunohematopoietic murine tumor cells ectopically expressing Fc gamma RIIB1 (B1) were recently shown to express a higher tumorigenicity phenotype than cells not expressing this receptor. Utilizing a genetic approach we studied the possible contribution of a soluble form of B1 to tumor enhancement. A mutated form of the B1, lacking the cleavage site responsible for the generation of soluble B1 was produced using gene splicing by overlap extension PCR. A deletion confirmed by sequence analysis from 172 to 178 residues was generated. Stable transfectants expressed the B1 deleted form (B1 Delta) both as specific RNA and as a membrane protein receptor allowing a low level of ligand binding. The soluble form of B1 was undetectable in tissue culture supernatants of Bib transfected cells while it was present in supernatants of wild type B1-transfectants. Stable B1 Delta transfectants were significantly more tumorigenic than negative control transfectants. Tumor incidence was almost as high as that of intact B1 and lagged in the latency period before the appearance of palpable tumors. It is suggested that the soluble B1 has a minimal contribution to tumor enhancement.

Contribution of the intracellular domain of murine Fc-gamma receptor type IIB1 to its tumor-enhancing potential

We have previously shown that Fc gamma receptor type II B1 (Fc(gamma)RIIB1), when expressed on non-lymphoid tumor cells, significantly enhanced their tumorigenic phenotype. This study elucidates the role of the intracellular domain of Fc(gamma)RIIB1 in the enhancement of the malignant phenotype of polyoma-transformed 3T3 cells. We investigated the tumorigenic potential conferred by different variants of the receptor: Fc(gamma)RIIB1, a full-length receptor (B1) whose intracellular region is encoded by exons 8, 9 and 10; Fc(gamma)RIIB2, a spliced variant (B2) whose cytoplasmic domain comprises exons 9 and 10 and lacks exon 8; and Fc(gamma)RIIB1-CT53, a deleted mutant whose cytoplasmic domain contains the fragment encoded by exon 8 alone. We have investigated various properties of cells transfected with each of the above variants: tumorigenicity in syngeneic mice, formation of colonies in soft agar, growth rate, production of soluble receptor and capping of the ligand-bound receptor. Results show that while the presence of exon 8 did not enhance growth rate in vitro or production of soluble Fc(gamma)R, it did enhance the tumorigenic phenotype of transfected cells (both in vivo and in vitro growth in soft agar). B1-expressing cells exhibited a significantly higher tumorigenic phenotype than B2 cells. The presence of exon 8 alone (CT53 mutant) conferred the transfected cells a higher tumorigenic phenotype than Fc(gamma)R-negative control cells but lower than intact B1 or B2 cells, indicating that the presence of B1-specific exon 8 is not sufficient but that the presence of an intact B1 intracellular domain is essential, for conferring the high tumorigenicity phenotype upon cells. We conclude that the capping, following ligand binding contributed by exon 8, and the function contributed by the specific localization of exons 9 and 10 in B1 cells may determine their malignant phenotype.

The murine Fc-gamma (Fc gamma) receptor type II B1 is a tumorigenicity-enhancing factor in polyoma-virus-transformed 3T3 cells

The murine receptor for the Fc portion of IgG is a molecule expressed by cells of the immune system. This study suggests the hypothesis that Fc gamma receptor type II B I (Fc gamma RIIB I) functions as a progression-enhancing factor when expressed ectopically on non-lymphoid tumor cells. It has been shown previously that BALB/c 3T3 cells transformed in vitro with polyoma virus (PyV) do not express Fc gamma RII but acquire the expression of this receptor following an in vivo passage in syngeneic mice. The specific Fc gamma RII transcript present in tumor cells was identified in this report as Fc gamma RIIB I (BI). In order to determine whether or not the ectopically expressed Fc gamma RII plays a role in the progression of these transformed cells, PyV-transformed 3T3 cells were transfected with BI-cDNA. The BI transfected cells were tested for their ability to form local tumors in syngeneic mice, as compared to transfected cells which express the co-transfecting neomycine resistance (neores) DNA alone or together with the lacZ gene. Fc gamma RIIB I expressors exhibited a significantly higher tumorigenic phenotype than FcR-negative controls, though both types of cells exhibited the same growth curve in vitro. The ability of Fc gamma RIIB I to act as a potentially tumorgenicity-enhancing factor was also demonstrated as Fc gamma RII was expressed by tumor cells, originating from inoculated Fc gamma RIIB I-transfected cells, or from inoculation of a mixture of receptor-positive and -negative cells. B I-expressing cells dominated the tumor-cell population over non-expressors. This dominance strengthened the hypothesis that FcR plays a role in tumor progression in vivo.

A controlled evaluation of psychoeducational family intervention in a rural Chinese community

BACKGROUND

The shortage of mental health care in rural China might be tackled by community care. This study tests the hypothesis that family intervention increases patients' treatment compliance, which is crucial in community care.

METHOD

A cohort of psychiatric patients were randomly selected to a controlled trial for four months. Compliance rates, clinical and social outcomes were measured double-blindly.

RESULTS

The compliance rate was increased significantly in the trial group, and they had better clinical and social outcomes.

CONCLUSIONS

Family intervention is an effective method of improving treatment compliance and should be an important part of community mental health care.

FcR may function as a progression factor of nonlymphoid tumors

Tumor progression is a multistep process involving genetic and epigenetic changes in a transformed clone. Some of these changes may be induced by host factors which may also select for transformed cellular variants with a high ability to survive and propagate. In this article we review studies showing that receptors for the Fc portion of IgG may be expressed on cells from human or animal tumors of nonlymphoid origin. We also review data demonstrating that at least with respect to cells transformed in vitro with Polyoma virus, transformation per se is not sufficient for the induction of Fc receptor expression. We also summarize preliminary data showing that Fc receptor expression is causally involved in conferring a high malignancy phenotype upon transformed cells. Possible mechanisms to explain these observations are discussed.

Possibilities of interference with the immune system of tumor bearers by non-lymphoid Fc gamma RII expressing tumor cells

The ectopic expression of Fc gamma RII by PyV transformed 3T3 cells derived from tumors of long latency has been established. It was suggested that this expression is one of several changes conferring upon the cells an increased capacity for survival. We found that in one case cells expressing a very high level of Fc gamma RII had also a very high metastatic phenotype as compared to FcR negative cells. Direct evidence that Fc gamma RIIbl functions as a progression factor was provided by transfection experiments. The transfected gene conferred an increased malignancy and invasive phenotype upon PyV or c-Ha-ras transformed cells. In the present study we tested the possibility that Fc gamma RII expressing tumor cells could interfere with the immune system. The following subjects were investigated: 1) The ability of Fc gamma R on the tumor cells to bind the ligand and/or release IBF. 2) The effect of a local accumulation of ligand and/or IBF (assumed to take place in situ in the tumor) on Fc gamma RII expressing T cells. It was found that both tumor-derived receptor positive and beta l transfected PyV transformed cells were capable of binding aggregated mouse IgG. The binding of bivalent ligand was followed by an increase in membrane Fc gamma RII expression. Also both types of cells were capable of releasing IBF. We then tested the possibility that a local accumulation of IgG within the tumor could effect Fc gamma R expressing T cells. It was found that aggregated mouse IgG (as well as IgGl) could stimulate the proliferation of the T cell hybridoma (T2D4) and other Fc gamma RII expressing T cells. We also found that the expression of beta Fc gamma RII specific mRNA peaked at the logarithmic phase of T2D4 cultures, in parallel with their maximal potential to release IBF. Several pathways for interference with the immune system are suggested.

Phenotypic properties of 3T3 cells transformed in vitro with polyoma virus and passaged once in syngeneic animals

Cloned BALB/c 3T3 cells transformed in vitro with polyoma virus (PyV) acquired a higher tumorigenicity phenotype after a single in vivo passage. Some of the in vivo passaged cells (CTC cells) exhibited also a higher metastatic phenotype than cells from the same clones that were maintained only in culture (C cells). A phenotypic comparison between CTC and C cells was performed. It was found that most CTC lines exhibited a higher binding to laminin compared to their clonal C cell ancestors. Some CTC cells were less sensitive to the cytotoxic effects of TNF-alpha than the corresponding C cells. CTC cells originating from tumors which appeared after a long latency period (late tumors) tended to express Fc gamma RII while CTC cells originating from tumors which appeared after a short latency period (early tumors) as well as the corresponding C cells tended not to express Fc gamma RII. The expression of a membrane epitope recognized by a monoclonal antibody expressing specificity towards PyV transformed cells, was down-regulated on late tumor cells compared to early tumor cells. Transfection of cloned PyV-transformed BALB/c 3T3 cells with the beta 1Fc gamma RII gene augmented the tumorigenicity and metastatic phenotype of the transfectants compared to control transfectants.

In vivo acquisition of Fc gamma RII expression on polyoma virus-transformed cells derived from tumors of long latency

BALB/c 3T3 cells transformed in vitro with polyoma virus were cloned and passaged once in syngeneic mice. Resulting tumors from each clone were explanted and recultured. Expression of receptor for Fc of IgG (Fc gamma RII) in the original in vitro maintained clones and in cells derived from tumors elicited by the respective cells was measured at the protein level as well as at the mRNA level. Clones were assayed in pairs. The ancestor in vitro maintained clones [designated cultured cells (C)] were compared with cells derived from the same clones after a single passage in vivo followed by explantation and reculturing [designated cultured-tumor-cultured cells (CTC)]. C cells of any of the tested clones did not express Fc gamma RII. On the other hand, certain CTC cells were positive. The Fc gamma RII-positive cells were derived from tumors appearing after a long precancer latency period (greater than 140 days). CTC cells derived from tumors that appeared after shorter latency periods (less than 80 days) were Fc gamma RII negative. These results were obtained both by using radioimmunoassay and monoclonal antibodies against mouse Fc gamma RII as well as by Northern blot analysis using the Fc gamma RII complementary DNA probe. The involvement of macrophages as the Fc gamma RII-expressing cells in CTC cells was excluded. Fc gamma RII expression was down-regulated in CTC cells as a function of time following their explantation into culture. Fc gamma RII expression could be up-regulated in these cells and induced on C cells by maintaining the cultured cells in the presence of normal mouse serum or recombinant interferon. We also tested the expression of Fc gamma RII on CTC cells following their inoculation into syngeneic mice for a second time (CTCx2 cells). The results showed a positive correlation between Fc gamma RII expression in the inoculated ancestor CTC cells and on the CTCx2 cell progeny.

Some cellular and molecular characteristics of high and low tumorigenicity variants of polyoma-virus transformed cells

We analyzed several cellular and molecular properties of BALB/c 3T3 cellular clones transformed in vitro with polyoma virus and exhibiting a high or low tumorigenicity phenotype. We also analyzed the same clones after a single in vivo passage in syngeneic mice. This passage invariably induced and/or selected variants exhibiting a very high tumorigenicity phenotype. BALB/c mice bearing tumors induced by the inoculation of the above cells, regardless of their tumorigenicity phenotype, have a lower number of L3T4 positive splenocytes than appropriate controls. The response to Con-A of spleen cells from such mice was also suppressed. Concomitantly, an increase in Mac-1 positive splenocytes could be measured. In spite of the non-specific suppression of T cells, spleen cells from tumor-bearers showed a specific proliferative response to polyoma antigens. Molecular analysis of polyoma transformed cells showed no differences between the various cells with respect to integration of the polyoma viral genes or with respect to src, myc and fos proto-oncogenes. In vitro maintained cells and in vivo passaged cells seemed to differ, however, in the content of polyoma middle T. Whereas polyoma virus transformed cells maintained only in culture never expressed low affinity receptors for IgG (Fc gamma RII), certain in vivo passaged cells did. This expression could be measured both at the protein and the mRNA level. Those in vivo passaged cells which expressed F alpha RII gave tumors following a long latency period. Ongoing experiments will indicate whether or not Fc gamma RII expression is linked to long latency of tumor development.

Increased expression of Fc gamma receptor in cancer patients and tumor bearing mice

In this study we report on some lines of ongoing research performed in our laboratory, in relation to the increased expression of FcR on tumor cells, as well as on cells present in the tumor-bearing host, and its possible role in tumor progression. In a previous study we have shown that a Polyoma virus (PyV)-induced anaplastic carcinoma (SEYF-a tumor) contained an FcR-expressing subpopulation of tumorigenic cells. We tested the effect of in vivo passaging of FcR-expressing and of non-FcR-expressing sub-populations of SEYF-a tumor cells on the expression of FcR, as revealed by the ability of these cells to bind the 2.4G2 monoclonal antibody, which is directed against mouse Fc gamma 2b/gamma 1R. It was found that upon in vivo passaging these two sub-populations became practically identical in their ability to bind anti-Fc gamma R antibody. On the other hand, in vitro passaging of FcR-expressing SEYF-a cells resulted in a gradual decrease in the expression of Fc gamma R. These results, indicating that the expression of Fc gamma R on tumor cells, per se, is dependent on a factor present in the in vivo environment were confirmed using 3T3 cells transformed in vitro by PyV (C) and forming tumors at first injection to mice (CTC). C cultures of various clones did not express Fc gamma R, while CTC cultures (cultures from tumors) became positive. We also detected an increase in the level of a soluble form of Fc gamma 2b/gamma 1R in the circulation of mice bearing PyV induced tumors. This increase paralleled the appearance of palpable tumors. A similar pattern of increase was observed in mice inoculated with the c-H-ras transformed tumorigenic clone 8/F/5, but not in mice inoculated with non-tumorigenic 3T3 cells. Data published by us show that metastatic breast cancer patients had significantly elevated Fc gamma R levels on their peripheral blood mononuclear cells (PBMC). Experiments presented here indicate a direct correlation between increased Fc gamma R levels on PBMC and tumor mass in colon, ovary and lung metastatic carcinoma patients. The possibility that malignantly transformed cells have the potential to cause proliferation of Fc gamma R expressing T cells was tested. It was found that extract derived from r-H-ras transformed 3T3 cells triggers the proliferation of a T cell hybridoma expressing Fc gamma R.

Correlation of Fc gamma receptors on peripheral blood mononuclear cells and survival in patients with metastatic breast cancer

Patients with carcinomas have elevated levels of Fc receptors for IgG (Fc gamma R) on their peripheral blood mononuclear cells (PBMC). The purpose of the present study was to determine whether there is a correlation between Fc gamma R levels on PBMC and survival in patients with metastatic breast cancer. Binding assays were performed on PBMC using 125I-labeled fibrinogen complexed with rabbit IgG (or as a control F(ab')2) anti-human fibrinogen. Twenty-two metastatic breast cancer patients had significantly (p less than 0.001) elevated Fc gamma R levels as compared to either 22 breast cancer patients receiving adjuvant chemotherapy following mastectomy without clinical evidence of tumor, or to 34 non-malignant controls. Significantly more metastatic patients with elevated Fc gamma R levels died at 6 months (p less than 0.001) as compared to those with low levels. A direct correlation between Fc gamma R levels and hazard probability was found (correlation coefficient = 0.3321, p less than 0.005). These results raise the possibility that Fc gamma R levels on PBMC from metastatic breast cancer patients may be clinically useful as a prognostic marker of disease activity.

Expression of Fc gamma receptors on a subpopulation of nonlymphoid tumor cells and its enrichment

Nonadherent Fc gamma receptors (Fc gamma R) expressing cells from SEYF-a tumors that form rosettes with sheep erythrocytes coated with IgG antibodies (EA) were isolated by Percoll density gradients. The EA-IgG rosette-forming cells were characterized by the parameters of 1) binding of IgG immune complexes; 2) binding of purified monoclonal antibodies against mouse FcR; 3) sensitivity to complement-dependent lysis mediated by syngeneic anti-SEYF-a antibodies; 4) expression of parental H-2 antigen when grown in F1 hybrids; 5) incorporation of [125I]5-iodo-2'-deoxyuridine; and 6) growth in syngeneic mice. The nonadherent EA-IgG rosette-forming cell population was found to be composed of both host lymphocytes as well as of tumor cells. Tumor-seeking lymphocytes then were removed from SEYF-a tumors by velocity sedimentation on Percoll. The remaining cell population was tumorigenic and expressed FcR, as well as tumor antigens. These tumor EA-IgG rosette-forming cells exhibited a very low rate of DNA synthesis compared with that of non-rosetting tumor cells.

Circulating cellfree Fc gamma 2b/gamma 1 receptor in normal mouse serum: its detection and specificity

By using intact or Fab fragments of rat monoclonal antibodies against murine Fc gamma 2b/gamma 1 receptor, in a solid phase radioimmunoassay, we demonstrated the occurrence of circulating cellfree Fc gamma 2b/gamma 1 receptors (Cf-Fc gamma 2b/gamma 1R) in normal mouse serum. These Cf-Fc gamma 2b/gamma 1R were removed from serum by affinity chromatography by using Sepharose columns coupled with IgG but not by Sepharose coupled with F(ab')2 fragments. Furthermore, the material retained by and eluted from the Sepharose IgG column reacted with the monoclonal antibody; these results support a direct relationship between the antigenic and the functional Cf-Fc gamma 2b/gamma 1R that were detected in serum. This Cf-Fc gamma 2b/gamma 1R was found in all the 39 normal mouse sera that were tested. The results seemed to indicate that aging may be associated with increased levels of Cf-Fc gamma 2b/gamma 1R and that levels of circulating Fc gamma R may be under genetic regulation. By forming complexes with circulating IgG within the blood stream, such Cf-Fc gamma 2b/gamma 1R may modulate some of the functions in which the Fc portion of Ig is involved.

Circulating cellfree Fc gamma 2b/gamma 1 receptor in normal mouse serum: its detection and specificity

By using intact or Fab fragments of rat monoclonal antibodies against murine Fc gamma 2b/gamma 1 receptor, in a solid phase radioimmunoassay, we demonstrated the occurrence of circulating cellfree Fc gamma 2b/gamma 1 receptors (Cf-Fc gamma 2b/gamma 1R) in normal mouse serum. These Cf-Fc gamma 2b/gamma 1R were removed from serum by affinity chromatography by using Sepharose columns coupled with IgG but not by Sepharose coupled with F(ab')2 fragments. Furthermore, the material retained by and eluted from the Sepharose IgG column reacted with the monoclonal antibody; these results support a direct relationship between the antigenic and the functional Cf-Fc gamma 2b/gamma 1R that were detected in serum. This Cf-Fc gamma 2b/gamma 1R was found in all the 39 normal mouse sera that were tested. The results seemed to indicate that aging may be associated with increased levels of Cf-Fc gamma 2b/gamma 1R and that levels of circulating Fc gamma R may be under genetic regulation. By forming complexes with circulating IgG within the blood stream, such Cf-Fc gamma 2b/gamma 1R may modulate some of the functions in which the Fc portion of Ig is involved.

A radioimmunoassay with monoclonal antibodies for the detection of antigenic cell-free Fc receptor

Making use of 125I-labelled monoclonal rat antibodies against mouse Fc receptor we have developed a solid-phase radioimmunoassay for cell-free antigenic mouse Fc receptor (FcR). An 80% acetone solution was used for fixation of relatively large amounts of soluble proteins on PVC microtiter plates. As a result of this treatment FcR practically lost its activity to bind the Fc portion of an IgG molecule but retained its antigenicity, the binding of specific anti-FcR (aFcR) antibody being increased following acetone fixation. Concentrations of cell-free FcR in NP-40 extracts of FcR-expressing cells were calculated from the linear part of a standard curve and expressed in units of antigenic activity, 1 unit being the amount of antigenic FcR capable of binding 1 microgram of 125I-aFcR. The method may be used for detecting cell-free FcR as a minor constituent in a mixture of proteins.

Studies on the level of natural antibodies reactive with various tumor cells during urethane carcinogenesis in BALB/c mice

Serum from young normal BALB/c mice was found to contain IgM antibodies able to mediate complement-dependent lysis of certain syngeneic or allogeneic tumor target cells. The titer of such naturally occurring antitumor antibodies ( NATA ) was found to increase with aging. A longitudinal serological study comparing the cytotoxicity potential of NATA from normal and from urethan-treated BALB/c mice was performed. It was found that urethan-treated mice that did not develop primary lung-adenomas within the duration of the experiment had significantly lower NATA titers, against one out of 4 target cells assayed, than urethan-treated animals that developed lung adenomas. This difference was evident in two independent experiments. The results suggested that the lower NATA activity of the urethan-treated mice that did not develop tumors existed even before exposure to the carcinogenic insult. This raises the possibility that certain populations could be segregated according to their natural antibody profile into those individuals which will develop primary tumors within a certain period if exposed to a subthreshold amount of carcinogen, and those which will not.

Separation of tumor-seeking small lymphocytes and tumor cells using Percoll velocity gradients

Using the polyoma virus-induced ascitic SEYF-a tumor, we evaluated isopycnic and velocity sedimentation gradients of Percoll as methods for separating tumor-seeking lymphocytes and tumor cells. It was established that the velocity sedimentation method is suitable for separation of small lymphocytes lodging within the SEYF-a tumor. This was confirmed by a serological analysis of the separated SEYF-a cell population. The results of this study strongly support our previously reported data demonstrating the in vivo coating of the tumor cells proper with potentially cytotoxic antibodies.

Natural cellular reactivities mediated by splenocytes from mice bearing three types of primary tumor

The ability of splenocytes from mice bearing three types of primary tumor to lyse YAC-I target cells (NK activity) and to inhibit [125I]dUrd incorporation ([125I]dUrd I-I = cytostasis) into B16-F10 target cells was compared to the ability of normal splenocytes to perform such activities. The tumor systems used were urethane-induced lung adenomas in BALB/c mice, dimethylbenzanthracene (DMBA)-induced tumors in hormonally-stimulated BALB/c mice and mammary tumors in force-bred C3HeB mice. The two types of natural cellular reactivity in lung adenoma-bearing mice were unaffected. The NK activity of mice bearing DMBA and forced-breeding-induced tumors was suppressed. The cytostatic ability of splenocytes from mice bearing DMBA-induced tumors was significantly elevated. The spleens of mice bearing primary DMBA-induced tumors contained cells able to suppress NK activity or to compete against target cells for NK cells.