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PubMed1994

Results in the United States with sperm microaspiration retrieval techniques and assisted reproductive technologies. The Sperm Microaspiration Retrieval Techniques Study Group.

Improved methods of urological microsurgery and of various assisted reproductive technologies have resulted in the ability to achieve pregnancies with sperm aspirated microsurgically from men with bilateral congenital absence of the vasa deferentia or with ductal obstructions that cannot be surgically reconstructed. A survey was conducted of the results of such procedures performed in the United States during approximately 2 years. Female partner ovarian stimulation was initiated in 219 instances at 22 centers. Of the 219 procedures 23 (11%) were terminated without attempting any form of gamete fertilization or insemination of the wife for various reasons (no sperm or too few sperm retrieved, poor to absent sperm motility or poor quality eggs). The etiology of azoospermia in the 219 procedures was congenital absence of the vasa deferentia in 115 cases (52%), other congenital conditions in 15 (7%), failed vasectomy reversal in 37 (17%), infection in 4 (2%), other conditions (mainly ejaculatory dysfunctions that did not respond to electroejaculation and complex ductal obstructions) in 26 (12%) and not specified in 22 (10%). When only patient sperm was used pregnancy was achieved in 12 of 115 wives (10%) of those men who had congenital absence of the vasa deferentia and in 0 to 14% of the wives of men whose azoospermia was caused by other conditions. Of the 219 menstrual cycles in which ovarian stimulation was initiated pregnancy occurred in 24 (11%) with patient sperm and in 9 (4%) with donor sperm. Of these 33 pregnancies a full-term, live delivery occurred in 17 (52%), while 8 (24%) were ongoing at the time of reporting, 2 (6%) miscarried, 3 (9%) were chemical pregnancies, 1 (3%) resulted in a stillborn child and the outcome was unknown in 2 (6%). This new therapy offers only a modest chance of pregnancy. However, it affords men with azoospermia the opportunity to achieve paternity with their own sperm when other therapies are not available or applicable.

Epididymis↗
PubMed1979

The role of sensory attributes as retrieval cues or as interference in retrieval of information from episodic memory.

The sensoty attributes of to-be-remembered (TBR) events and of distractor stimuli were systematically manipulated (both within and between modalities) in two Brown-Peterson tasks [experiments 1 (N = 40 male and female university students or faculty) and 2 (N - 22 male and female undergraduates)] and in a delayed recognition task (Experiment 1). Performance on these recall and recognition tasks (in which the semantic attributes of the TBR events were relatively controlled) was consistent with episodic theory. Memory of an event was reasonably completely described in terms of (a) the degree of overlap between the perceptible properties of the retrieval environment and of the memory trace of the event and (b) the perceptible similarities between the memory trace of the event and the traces of information encoded temporally adjacent to it. These sensory encoding specificity effects (as well as other research reviewed) were interpreted as demonstrations that a semantic interpretation of the encoding specificity principle cannot account for all encoding specificity phenomena.

Cues↗
PubMed2006

Heat-induced antigen retrieval: what are we retrieving?

Of all molecular aspects lost and recovered during formalin fixation and antigen retrieval, respectively, electrostatic charges have probably received the least attention. This review will focus on our work during the past 7 years. It strongly supports the tenet that electrostatic charges, i.e., net negative on antigens and net positive on antibodies, play an important part in immune reactions and therefore should be given greater attention when focusing on quality control in immunohistochemistry.

Antibodies↗
PubMed1992

A prospective study comparing the outcome of oocytes retrieved in the aspirate with those retrieved in the flush during transvaginal ultrasound directed oocyte recovery for in-vitro fertilization.

OBJECTIVE: To study prospectively the fate of oocytes collected from the follicular aspirate and subsequent flushes during transvaginal ultrasound directed oocyte recovery for in-vitro fertilization (IVF). SETTING: A tertiary referral assisted conception centre. SUBJECTS: 100 consecutive patients undergoing 100 cycles of IVF. Four patients were withdrawn because their embryos were electively cryopreserved. Therefore 96 cycles were studied. MAIN OUTCOME MEASURES: The oocyte recovery rate, viability, fertilization and cleavage rates and outcome of embryos generated from oocytes that were obtained from either the initial aspirate (A1), dead space in the collecting system (A2) or the first two 2 ml flushes (F1 and F2) were compared. RESULTS: The overall oocyte recovery rate was 87.8%. Of the 1046 oocytes collected, 40.3% were from A1, 41.3% from A2, 13.7% from F1 and 4.7% from F2. There were comparable numbers of viable and fertilized oocytes and cleaved, transferred and frozen embryos in tubes A1 and A2 but all these parameters were significantly lower in tubes F1 and F2 (P < 0.0001). All these parameters were also significantly higher in F1 compared with F2 (P < 0.001), except for the number of embryos frozen, in which there was no difference. The overall pregnancy rate per cycle was 28.1% and the pregnancy rate per embryo transfer was 31.0%. There were no pregnancies in any of the cycles in which embryos originating from F2 were transferred, nor were there pregnancies in cycles in which only embryos from F1 were transferred. CONCLUSION: Follicular aspiration together with one 2 ml flush maximises the recovery of oocytes that will result in pregnancies.

Adult↗
PubMed2005

Naming very familiar people: when retrieving names is faster than retrieving semantic biographical information.

One of the most reliable findings in the literature on person indentification is that semantic categorization of a face occurs more quickly than naming a face. Here we present two experiments in which participants are shown the faces of their colleagues, i.e., personally familiar people, encountered with high frequency. In each experiment, naming was faster than making a semantic classification, despite the fact that the semantic classifications were highly salient to the participants (Experiment 1: highest degree obtained; Experiment 2: nationality). The finding is consistent with models that allow or parallel access from faces to semantic information and to names, and demonstrates the need for the frequency of exposure to names to be taken into account in models of proper name processing e.g. Burke, Mackay, Worthley and Wade (1991).

Adult↗
PubMed1998

Prefrontal cortex and recognition memory. Functional-MRI evidence for context-dependent retrieval processes.

Functional neuroimaging studies of episodic recognition memory consistently demonstrate retrieval-associated activation in right prefrontal regions, including the right anterior and right dorsolateral prefrontal cortices. In theory, these activations could reflect processes associated with retrieval success, retrieval effort or retrieval attempt; each of these hypotheses has some support from previous studies. In Experiment 1, we examined these functional interpretations using functional MRI to measure prefrontal activation across multiple levels of recognition performance. Results revealed similar patterns of right prefrontal activation across varying levels of retrieval success and retrieval effort, suggesting that these activations reflect retrieval attempt. Retrieval attempt may include initiation of retrieval search or evaluation of the products of retrieval, such as scrutiny of specific attributes of the test item in an effort to determine whether it was encountered previously. In Experiment 2, we examined whether engagement of retrieval attempt is context-dependent by varying the context in which retrieval was performed; this was done by changing test instructions. Importantly, study and test stimuli were held constant, with only the test instructions varying across conditions. Results revealed that the pattern of right prefrontal activation varied across retrieval contexts. Collectively, these experiments suggest that right prefrontal regions mediate processes associated with retrieval attempt, with the probability of engaging these regions depending upon the retrieval context. Conflicting results across previous studies may be reconciled if the influence of retrieval context on the adopted retrieval strategy is considered. Finally, these results suggest that right prefrontal regions activated during recognition are not critical for successful performance as similar magnitudes of activation were present across multiple levels of performance. These findings reconcile imaging results with the selective effects of prefrontal lesions on retrieval-intensive episodic memory tests.

Adolescent↗
PubMed1992

Randomised comparative study in 217 women of three disposable plastic IUCD thread retrievers.

OBJECTIVE: To assess the relative efficacy of three disposable plastic instruments in the retrieval of 'missing' IUCD threads. DESIGN: A prospective randomised comparative single centre study. SETTING: Family Planning Clinic in London, UK. SUBJECTS: 217 of 350 IUCD users referred to the research team with 'missing' IUCD threads entered the study. INTERVENTION: All women initially underwent exploration of the endocervical canal with Spencer Wells forceps. When this procedure did not retrieve the threads, the patients were entered into the study. A maximum of two randomly chosen plastic IUCD thread retrievers were then used in any one patient to explore the uterine cavity and capture the 'missing' threads. The order in which the two retrievers were employed was also determined at random. Four separate entries into the uterine cavity were permitted with each instrument, the endocervical canal being explored with Spencer Wells forceps after each retraction of the instrument to identify the possible descent of the threads. MAIN OUTCOME MEASURES: Threads brought down beyond the external cervical os, or threads brought to within the endocervical canal and then grasped by Spencer Wells forceps. RESULTS: In approximately 40% of all patients, the threads were retrieved with Spencer Wells forceps alone and a further 40% with the disposable plastic retrievers. About 5% had no retrievable threads, and only 2.5% of the referred patients required general anaesthesia for removal of their IUCD. The analysis of the comparative trial was confined to the 197 patients with retrievable threads which could not be brought below the external os with Spencer Wells forceps. The first plastic retriever used was successful in 50% of patients. The Retrievette (59%) and the Emmett (53%) performed better than the Mi-Mark Helix (37%) in this study. The difference was statistically significant (P = 0.03) and the 95% confidence interval for the difference of the Mi-Mark Helix from the other two retrievers was 4% to 33%. This retrieval rate for the Mi-Mark Helix was much worse than in previously reported studies, though one doctor did have a better success rate with this retriever. The success rates, using a second plastic retriever randomly chosen from the two not used in the first attempt, were almost identical to those observed with the first retrievers: 63%, 56% and 36%. The success rate did not appear to be influenced by the length of thread, day of cycle, device type or parity. The success of the second retriever tried did not seem to be influenced by the retriever that had failed previously. CONCLUSIONS: Based on our experience, the initial exploration of the endocervical canal with Spencer Wells forceps is invaluable. If this simple manoeuvre fails to retrieve the 'missing' threads, either the Retrievette or the Emmett thread retrievers are useful tools in general practice or in the family planning clinic setting.

Female↗