What is "special" about face perception?

There is growing evidence that face recognition is "special" but less certainty concerning the way in which it is special. The authors review and compare previous proposals and their own more recent hypothesis, that faces are recognized "holistically" (i.e., using relatively less part decomposition than other types of objects). This hypothesis, which can account for a variety of data from experiments on face memory, was tested with 4 new experiments on face perception. A selective attention paradigm and a masking paradigm were used to compare the perception of faces with the perception of inverted faces, words, and houses. Evidence was found of relatively less part-based shape representation for faces. The literatures on machine vision and single unit recording in monkey temporal cortex are also reviewed for converging evidence on face representation. The neuropsychological literature is reviewed for-evidence on the question of whether face representation differs in degree or kind from the representation of other types of objects.     

In vitro processing of herpes simplex virus type 1 DNA replication intermediates by the viral alkaline nuclease, UL12

Herpes simplex virus type 1 (HSV-1) DNA replication intermediates exist in a complex nonlinear structure that does not migrate into a pulsed-field gel. Genetic evidence suggests that the product of the UL12 gene, termed alkaline nuclease, plays a role in processing replication intermediates (R. Martinez, R. T. Sarisky, P. C. Weber, and S. K. Weller, J. Virol. 70:2075-2085, 1996). In this study we have tested the hypothesis that alkaline nuclease acts as a structure-specific resolvase. Cruciform structures generated with oligonucleotides were treated with purified alkaline nuclease; however, instead of being resolved into linear duplexes as would be expected of a resolvase activity, the artificial cruciforms were degraded. DNA replication intermediates were isolated from the well of a pulsed-field gel ("well DNA") and treated with purified HSV-1 alkaline nuclease. Although alkaline nuclease can degrade virion DNA to completion, digestion of well DNA results in a smaller-than-unit-length product that migrates as a heterogeneous smear; this product is resistant to further digestion by alkaline nuclease. The smaller-than-unit-length products are representative of the entire HSV genome, indicating that alkaline nuclease is not inhibited at specific sequences. To further probe the structure of replicating DNA, well DNA was treated with various known nucleases; our results indicate that replicating DNA apparently contains no accessible double-stranded ends but does contain nicks and gaps. Our data suggest that UL12 functions at nicks and gaps in replicating DNA to correctly repair or process the replicating genome into a form suitable for encapsidation.     

Laparoscopic versus open appendectomy

BACKGROUND: Clinical manifestations and course of sickle-cell anemia are variable. Knowledge about the factors, possibly geographic, that influence prognosis are still scanty. POPULATION AND METHODS: Data of hospitalization and management of children with sickle-cell disease were studied during two years (1992-1993) in the Pediatric Unit of Libreville Hospital. They concerned 205 admissions of 171 children and 131 outpatients. RESULTS: The main causes of hospitalization were: acute anemia (36 cases before the age of 5 years); painful crisis whose frequency increased with age (23% before 5 years, 35% between 5 and 10, 42% after 10 years); infections, essentially pulmonary occurring early, and bone infections at any age. Eight children died (because a complication of their disease). Among the 131 outpatients, half were detected because pyrexia, anemia and/or more often "hand-foot syndrome". More than 60% had hepatomegaly, one third still had splenomegaly after five years of age and more than one third was icteric. More than half children older than ten years had growth disorders. Mean hemoglobin level was 7 g/dL. 21 of the 83 tested children for HBsAg were positive and only one out of 79 was positive for HIV. CONCLUSIONS: Clinical manifestations and course of sickle-cell anemia in our patients are similar to those reported in Congolese children. Genetic and environmental factors may be responsible for differences with children from other, in particular French, cohorts.     

Automatic measurement of arterial pressure

PURPOSE: To identify patients with lymphoma at risk for tumor lysis after chemotherapy. PATIENTS AND METHODS: The case records of 102 patients receiving combination chemotherapy for non-Hodgkin's lymphoma (intermediate to high-grade histology) were reviewed. Patients were considered to have "laboratory tumor lysis" if two of the following metabolic changes occurred within 4 days of treatment: a 25% increase in the serum phosphate, potassium, uric acid, or urea nitrogen concentrations, or a 25% decline in the serum calcium concentration. "Clinical tumor lysis" was defined as laboratory tumor lysis plus one of the following: a serum potassium level greater than 6 mmol/L, a creatinine level greater than 221 mumol/L, or a calcium level less than 1.5 mmol/L, the development of a life-threatening arrhythmia, or sudden death. RESULTS: Laboratory tumor lysis occurred in 42% of patients and clinical tumor lysis in 6%. There was no statistical difference in the frequency of either tumor lysis syndrome among lymphoma subgroups. Clinical tumor lysis occurred more frequently in patients with pretreatment renal insufficiency (serum creatinine level greater than 132 mumol/L) than in patients with normal renal function (36% versus 2%; p = 0.01). The development of azotemia correlated with high pretreatment serum lactate dehydrogenase concentrations (p < 0.01; r2 = 0.11). CONCLUSION: Clinically significant tumor lysis is a rare occurrence in patients with lymphoma when they are receiving allopurinol. However, tumor lysis can occur in patients with all types of moderate to high-grade non-Hodgkin's lymphoma. Patients with a high serum lactate dehydrogenase level or renal insufficiency are at increased risk for metabolic complications after chemotherapy and should be closely monitored.     

Complications of surgery for discogenic disease of the spine

Disc disease is benign and not life threatening. Its long-term prognosis is uncertain, and spontaneous recoveries are common. The decision to perform surgery thus carries with it a heavy responsibility to provide safe treatment. "Good safe surgical technique" is essential, but it is much more than a well-rehearsed routine procedure. From preoperative evaluation to surgery to postoperative care, the surgeon must look ahead to problems that might arise. Where anticipated risks cannot be avoided, they should be minimized, and when adverse events occur, active recognition will lead to early and accurate management.     

Liposome-cell interaction: transfer and intracellular release of a trapped fluorescent marker

When small, unilamellar lipid vesicles containing a high concentration of the fluorescent dye 6-carboxyfluorescein are incubated with either frog retinas or human lymphocytes, fluroescence distributes widely throughout each cell. Since "self-quenching" largely prevents the dye from fluorescing as long as it remains sequestered in vesicles, it is clear that a considerable amount of dye is released from the vesicles and diluted into the much larger volume of the cell.     

Familial psoriasis and HLA-B: unambiguous support for linkage in 97 published families

The existence of a psoriasis susceptibility locus, PSORS1 (HUGO/GDB-approved symbol), in or near the HLA region of chromosome 6 is strongly supported by a lod score analysis of HLA-B and psoriasis in 97 families from 16 published datasets. Families included in the dataset represent all the psoriasis families with usable HLA data that we could find in the published literature through May 1997. The recombination fraction between PSORS1 and HLA-B is estimated to be at or near 0.00, with a maximum two-point lod score of 23.7, assuming a dominant mode of inheritance with low (20%) penetrance at the PSORS1 locus. Although these families are geographically and ethnically diverse, there is no evidence for linkage heterogeneity at the HLA-linked locus in this analysis. We also conclude that the HLA-B17 allele, which is strongly associated with psoriasis, is unlikely itself to contribute directly to psoriasis susceptibility; rather, the HLA-B locus is probably tightly linked to the PSORS1 locus. Finally, we raise the possibility of a two-locus/heterogeneity model as one way to reconcile several findings in the literature.     

Insulation lead failure: is it a matter of insulation coating, venous approach, or both?

Gag gene mutants of human immunodeficiency virus type 1 (HIV-1) were analyzed for their potentials of inhibiting the replication of wild-type (wt) HIV-2, the second AIDS virus, in a single-round of viral replication. Of twenty-two HIV-1 gag mutants examined, seven were found to efficiently interfere with the replication of wt HIV-2. Some mutants, which can suppress the replication of wt HIV-1, did not show this inhibitory effect. These mutants were defective at the late phase of viral replication. A mutant designated NL-C1a was demonstrated to be very effective against the replication of HIV-1 and HIV-2 in monocytic cells as well as in lymphocytic cells.     

Regional difference in insulin inhibition of non-esterified fatty acid release from human adipocytes: relation to insulin receptor phosphorylation and intracellular signalling through the insulin receptor substrate-1 pathway

Increased mobilization of non-esterified fatty acids (NEFA) from visceral as opposed to peripheral fat depots can lead to metabolic disturbances because of the direct portal link between visceral fat and the liver. Compared with peripheral fat, visceral fat shows a decreased response to insulin. The mechanisms behind these site variations were investigated by comparing insulin action on NEFA metabolism with insulin receptor signal transduction through the insulin receptor substrate-1 (IRS-1) pathway in omental (visceral) and subcutaneous human fat obtained during elective surgery. Insulin inhibited lipolysis and stimulated NEFA re-esterification. This was counteracted by wortmannin, an inhibitor of phosphaditylinositol (PI) 3-kinase. The effects of insulin on antilipolysis and NEFA re-esterification were greatly reduced in omental fat cells. Insulin receptor binding capacity, mRNA and protein expression did not differ between the cell types. Insulin was four times more effective in stimulating tyrosine phosphorylation of the insulin receptor in subcutaneous fat cells (p < 0.001). Similarly, insulin was two to three times more effective in stimulating tyrosine phosphorylation of IRS-1 in subcutaneous fat cells (p < 0.01). This finding could be explained by finding that IRS-1 protein expression was reduced by 50 +/- 8% in omental fat cells (p < 0.01). In omental fat cells, maximum insulin-stimulated association of the p85 kDa subunit of PI 3-kinase to phosphotyrosine proteins and phosphotyrosine associated PI 3-kinase activity were both reduced by 50% (p < 0.05 or better). Thus, the ability of insulin to induce antilipolysis and stimulate NEFA re-esterification is reduced in visceral adipocytes. This reduction can be explained by reduced insulin receptor autophosphorylation and signal transduction through an IRS-1 associated PI 3-kinase pathway in visceral adipocytes.