Short-term culture of acute myeloid leukemia blasts: analysis of acquired susceptibility to activated natural killer cells

Following a cryopreservation step, short-term cultures of circulating leukemic blasts from a patient with acute myeloid leukemia (AML) were performed. Because cultured tumor cells became susceptible to natural killer (NK) activity, in vitro alteration of the blasts was studied. Immediately after thawing, cell suspensions consisted of a relatively homogeneous population of undifferentiated blasts. In culture, tritiated thymidine uptake by the leukemic cells was low during the first 24 hours and then increased (X20) to a peak on day 7. The cell concentration started to increase on day 4. On day 8, less than 10% of the cultured cells still appeared as undifferentiated blasts, whereas up to 60% were granular and 30% to 40% had a monocytoid morphology. Prior to being cultured, the blasts were resistant to resting and IL2- activated natural killing. When the kinetics of in vitro acquired susceptibility were studied, it was found that maximum cytotoxicity against these leukemic cells was reached within 24 hours. Thus, the blasts had become NK-sensitive prior to increase in DNA synthesis, proliferation, and differentiation based on morphological and cytochemical criteria. In contrast, there was a positive correlation between acquired susceptibility and surface expression of an activation antigen, termed TNKtar. To dissect further the mechanisms of acquired susceptibility, a series of six NK clones representing four distinct phenotypes of NK active lymphocytes were tested against the leukemic cells. Immediately after thawing, blasts were essentially resistant to all clones, whereas they were strongly killed by 5 of 6 clones when cultured for 24 hours. Cold target inhibition assays indicated that resistance of fresh blasts was likely to be due to a binding defect. These results suggested that tumor cells became susceptible because they surface-expressed NK target structure(s) in the early phase of an activation process leading to their proliferation and/or differentiation. This hypothesis was substantiated for one clone, termed JT9, because the anti-TNKtar antibody blocked cytotoxicity of JT9 cells against the cultured blasts.     

Cerebrospinal fluid profile of amyloid β42 (Aβ42), hTau and ubiquitin in North Indian Alzheimer's disease patients

Alzheimer's disease (AD) is the most common form of dementia, and is characterized by the degeneration of neurons and their synapses, and a higher number of amyloid plaques and neurofibrillary tangles (NFTs) compared with that found in non-demented individuals. Amyloid-β-peptides (Aβ) are major components of amyloid plaques in AD brain whereas NFTs are composed of Tau and associated with ubiquitin. The aim of the present study was to analyze the levels of Aβ42, hTau (total Tau) and ubiquitin in CSF of North Indian population. CSF Aβ42, Tau and ubiquitin were measured in CSF of AD patients as well as controls using ELISA assays. Here we report low Aβ42 levels in AD patients (324.24 ± 76.38 pg/ml) as compared to those in non-AD (NAD) (668.34 ± 43.13 pg/ml), neurological controls (NCs) (727.28 ± 46.49 pg/ml) and healthy controls (HCs) (976.47 ± 124.46 pg/ml). In contrast, hTau and ubiquitin levels were significantly high (568.65 ± 48.89 pg/ml and 36.82 ± 4.34 ng/ml, respectively) in AD patients compared to those in NAD, NC and HC. The hTau levels were 267.37 ± 36.64 pg/ml, 167.34 ± 44.27 pg/ml and 107.62 ± 24.27 pg/ml in NAD, NC and HC, respectively. Similarly, ubiquitin levels were 23.57 ± 2.32 ng/ml, 19.76 ± 3.64 ng/ml and 13.24 ± 4.56 ng/ml in NAD, NC and HC, respectively. In conclusion, low Aβ42 and high Tau–ubiquitin levels were found in North Indian AD patients.     

Paraspinal arteriovenous malformations with perimedullary venous drainage

Symptoms of chronic myelopathy in cases of paraspinal arteriovenous malformations are most often related to perimedullary venous drainage. Here, we report on three cases of such malformations that have unique epidural venous drainage. These thoracolumbar lesions manifested as isolated back pain (in two cases) and S1 lumboradicular pain (in one case). MRI presented evidence to suggest a diagnosis of these rare conditions, based on signs of vertebral erosion, signal loss (flow void) on T1- and T2-weighted imaging, and partial enhancement after gadolinium injection, with no signs of congestive myelopathy. Spinal angiography confirmed the presence of a paraspinal fistula and, at the same time, allowed treatment by intra-arterial onyx injection.     

Long-term outcome of forearm flee-flap phalloplasty in the treatment of transsexualism

OBJECTIVE

To assess the long‐term outcome of forearm free‐flap phalloplasty in transsexuals, as obtaining a satisfying neophallus in female‐to‐male transsexuals is a surgical challenge.

PATIENTS AND METHODS

We analysed retrospectively 56 transsexuals who had a phalloplasty using a radial forearm free‐flap in our department from 1986 to 2002. The complication rate was assessed by regular examination. Patient satisfaction was evaluated by a questionnaire about cosmetic aspects, sexual life and overall satisfaction.

RESULTS

The mean follow up was 110 months; 53 of the 56 patients (95%) currently have a neophallus, after a mean of six surgical procedures. Satisfaction was assessed in 53 patients using a specific questionnaire: 51 (93%) of the patients reported that the phalloplasty allowed them to accord their physical appearance with their feeling of masculinity. There were flap complications in 14 patients (25%); three (5%) flaps were lost, with one each due to early haematoma, cellulitis and late arterial thrombosis. The other 11 flap complications were all transitory, e.g. infection, haematomas and vascular thrombosis. There were prosthesis complications in 11 of 38 patients (29%). Moreover, seven of 19 patients (37%) who had a urethroplasty presented with complex strictures and fistulae that led to perineal urethrostomy.

CONCLUSION

Our study shows that phalloplasty with a forearm free‐flap leads to good results in term of flap survival and patient satisfaction. However, there was a high rate of complications. Patients must be clearly informed that the procedure can seldom be achieved in one stage.     

Stimulus generalization of fear responses: effects of auditory cortex lesions in a computational model and in rats

The conditioning of fear responses to a simple acoustic stimulus (pure tone) paired with footshock can be mediated by the transmission of auditory information to the lateral nucleus of the amygdala from either the auditory thalamus or the auditory cortex. We examined the processing capacity of the thalamo-amygdala pathway by making lesions of the auditory cortex and testing the extent to which conditioned fear responses generalized to tones other than the one paired with footshock. Two studies were performed, one in an anatomically constrained computational model of the fear conditioning network and the other in rats. Stimulus generalization was unaffected in both. These findings support the validity of the model as an approach to studying the neural basis of conditioned fear learning, and in addition suggest that the thalamo-amygdala pathway, possibly by the use of population coding, is capable of performing at least crude stimulus discriminations.      

d-生物素的立体专一性全合成研究

对confaione的d-生物素(1)全合成进行了改进,从半胱氨酸计算,总收率3.7%。5与4-溴代三苯膦丁酸甲酯进行Wittig-Schlosser缩合反应可立体专一性地转化成反式-烯(6)。以叠氮三甲基硅烷代替叠氮化锂亲核进攻9分子中C3-溴原子,可显著地提高顺式-叠氮内酰胺10的收率。