Discrimination and imitation of facial expression by neonates.

Human neonates (average age, 36 hours) discriminated three facial expressions (happy, sad, and surprised) posed by a live model as evidenced by diminished visual fixation on each face over trials and renewed fixations to the presentation of a different face. The expressions posed by the model, unseeen by the observer, were guessed at greater than chance accuracy simply by observing the face of the neonate, whose facial movements in the brow, eyes, and mouth regions provided evidence for imitation of the facial expressions.

Effect of increased blood oxygen affinity on work performance of rats.

Influence of altered blood oxygen affinity on maximal performance ability was evaluated in trained rats exercising to exhaustion in a graded treadmill test. Modification of blood oxygen affinity was achieved both by 2,3-diphosphoglycerate depletion, accomplished by exposure of animals to CO(2) and by exchange transfusion with blood exposed to bisulfite or stored in acid citrate dextrose, and by carbamylation of hemoglobin, produced by exchange transfusion of blood incubated with potassium cyanate. A decrease in oxygen tension at half-saturation of hemoglobin (P(50)) from 36 to 23 mm Hg produced a decrease in resting central venous oxygen pressure of about 12 mm Hg. During exercise it caused an average decrease in work performance of about 10%, which was equivalent to that performance decrement caused by a decrease in hemoglobin concentration of approximately 10%. When superimposed on anemia, this change in blood oxygen affinity again caused a similar decrease in performance over and above that due to anemia alone. A marked rightward shift of the in vivo oxygen dissociation curve during severe exercise may have compensated for the reduced in vitro P(50).

The effect of cardiac disease on hemoglobin-oxygen binding.

The relation between degree of cardiac functional impairment and changes in hemoglobin-oxygen affinity and 2,3-diphosphoglycerate (2,3-DPG) has been studied in 39 patients with noncyanotic heart disease. A progressive decline in hemoglobin-oxygen affinity was found with worsening cardiac function as assessed by cardiac index, arteriovenous oxygen (A-V O(2)) difference, and cardiac symptoms; this alteration in hemoglobin-oxygen binding represents a significant mechanism for adaptation to the limited oxygen supply imposed by the cardiac lesion. The highly significant correlation of mixed venous blood oxygen saturation (S[unk]V(VO2)) with 2,3-DPG and the position of the oxygen dissociation curve suggests that the level of deoxygenated hemoglobin is an important in vivo regulator of hemoglobin-oxygen affinity.

The epidermal growth factor receptor is required to maintain the proliferative population in the basal compartment of epidermal tumors.

Previous studies using keratinocytes from epidermal growth factor receptor (EGFR)-deficient mice revealed that the EGFR is not required for papilloma formation initiated by a mutant rasHa gene, although the tumors that develop are very small (A. A. Dlugosz et aL, Cancer Res., 57: 3180-3188, 1997). The current study used a combination of bromodeoxyuridine pulse-chase, proliferating cell nuclear antigen distribution, and differentiation marker analysis to reveal the following: (a) the EGFR was required to maintain the proliferative population in the basal cell compartment of papillomas; (b) in the absence of EGFR, cycling tumor cells migrated into the suprabasal compartment and initiated the differentiation program prematurely; and (c) these changes were associated with cell cycle arrest. Further analysis of v-rasHa-transformed EGFR-deficient keratinocytes in vitro indicated that such cells migrated more on and attached less to extracellular matrix components. Together, these studies reveal that an essential function for the EGFR pathway in squamous tumors is to maintain a proliferative pool of basal cells and prevent premature terminal differentiation.

Evaluation of artificial plasma for maintaining the isolated canine brain.

The use of canine erythrocytes suspended in artificial plasma to maintain the isolated brain was investigated in 18 preparations. Two plasmas were studied: One (AP1) contained electrolytes, amino acids, and albumin; the other (AP2) was similar to CSF and contained a mixture of 37 organic nutrients plus electrolytes and albumin. The CMRO2, CMRglu, and cerebral vascular resistance (CVR) were measured during 2 h of perfusion, and tissue high-energy phosphates were measured at the end of perfusion. The AP1 and AP2 groups were compared with control preparations perfused with canine red blood cells suspended in buffy coat-poor canine plasma. Both CMRO2 and ATP decreased to 60% of the control value; CVR increased to 187% of the control value in both groups following 2 h of perfusion. After 2 h of perfusion, the calculated value of intracellular pH (pHi)--based on creatine kinase equilibrium--remained normal (6.96) for the control brains, but decreased to 6.49 and 6.63, respectively, for the AP1- and AP2-perfused brains. Thus, there appears to be an eventual disruption of normal oxidative metabolism resulting in energy failure, possibly caused by the absence of an essential nutrient from the artificial plasma. For studies of intermediary metabolism in isolated normothermic brain, diluted whole blood appears to be the perfusate of choice.

Fludarabine and cytarabine as a sequential infusion regimen for treatment of adults with recurrent, refractory or poor prognosis acute leukemia.

We did a retrospective analysis on the safety and efficacy of sequential infusion fludarabine and cytosine arabinoside (ara-C) in treating refractory, recurrent or poor prognosis acute leukemia in adult patients. Forty-five adult patients with acute myelogenous leukemia (AML) or acute lymphoblastic leukemia (ALL) received a total of 68 courses of sequential continuous infusion of fludarabine for 2 days (total dose 71.5 mg/m(2) ) followed by 3 days of ara-C (total dose 7590 mg/m(2) ). Thirty-nine patients had refractory or recurrent disease, and six had other adverse prognostic features. Thirty-six patients had AML, seven had ALL, and two had CML in blastic phase. Complete remission was seen in 20 patients (44%), and partial remission in 5 patients (11%), giving a total response rate of 56%, similar for both AML and ALL. Duration of response to prior therapy did not affect the response rate. All 3 patients with Philadelphia chromosome positive ALL obtained complete remission. Median remission duration was 4.7 months (range 0.6-36.6), and median overall survival was 5.0 months (0.7-40+). Median overall survival was 10.1 months in responders. Pulmonary toxicity was seen in 8 patients, of whom 2 died from adult respiratory distress syndrome. No cardiac toxicity was observed, but 3 patients had transient cerebellar toxicity. Profound myelosuppression was seen in all patients. We conclude that the sequential infusion of fludarabine and ara-C is an effective non-cardiotoxic regimen for adults with refractory, recurrent or poor prognosis acute leukemia, may be particularly useful for resistant Philadelphia chromosome positive ALL, and may warrant further investigation in this subset. Pulmonary rather than neurological toxicity may be a unique side effect of the regimen.

Severe cold agglutinin disease and cryoglobulinemia secondary to a monoclonal anti-Pr2 IgM lambda cryoagglutinin.

OBJECTIVE: To present a case of cold agglutinin disease/cryoglobulinemia secondary to a monoclonal anti-Pr2 IgM lambda antibody, and review the literature on the occurrence of this antibody in cold-induced disease and the clinical disease associated with it. METHODS: Cryoantibody characteristics were evaluated by cold precipitation. The antigen specificity of the monoclonal IgM lambda antibody was evaluated using techniques of selective red blood cell absorption. RESULTS: In our patient, we were able to identify an antibody with both cryoglobulinemic and cold agglutinin (cryoagglutinin) properties. This antibody was found to be monoclonal IgM lambda with specificity to the Pr2 antigen on red blood cells. CONCLUSIONS: Monoclonal IgM lambda anti-Pr is a rarely found cold agglutinin antibody. In this report we describe the clinical course of a patient who had this antibody, which not only agglutinated red cells in the cold but also had cryoglobulin properties. The clinical illness of this man was characterized by severe acrocyanosis and digital necrosis with eventual organ necrosis and death. We also review the literature on cold induced disease due to monoclonal anti-Pr IgM lambda antibody. Our patient was found to be unique among the reports reviewed. Our case is the first to report both cold agglutinin and cryoglobulinemic properties with the evaluation of the thermal amplitudes of these activities of the antibody. Also, unlike the lymphoproliferative malignancy observed in the cold agglutinin-associated disease in the other reports, our patient's disease was associated with a monoclonal B-cell expansion on the spectrum between benign monoclonal gammopathy and a low grade lymphoproliferative disorder.

Maternal blood pressure in pregnancy and newborn irritability.

The neonatal period is being recognized as an important period for the development of patterns of interaction between mother and infant, and infant state has been shown to have a significant impact on mother--infant interactions. A major dimension of infant state, with implications for this interaction and for the development of later behaviour disorders, is the infant's irritability. Research with Navajo, Malay, Chinese and Tamil mothers and infants showed that normal variation in maternal blood pressure during pregnancy was related to newborn irritability as assessed with the Brazelton Scale. This relationship is discussed in terms of possible underlying mechanisms.

Fetal mediators of the relationships between increased pregnancy and labour blood pressure and newborn irritability.

A prospective study of primiparous English women and their newborns failed to replicate previous findings that greater irritability was related to higher maternal blood pressure during pregnancy and labour. This apparent lack of replication prompted a search for fetal variables capable of mediating the blood pressure--irritability relationships. Relative fetal growth retardation was found in newborns of women whose peak antenatal blood pressure occurred from 20 to 32 wk gestation. Prenatal growth retardation and exposure to either oxytocin-stimulated labour or higher maternal blood pressure during spontaneous labour were associated with lower intrapartum fetal heart rate. Lower heart rate, in turn, was associated with greater crying and more frequent changes of state during behavioural assessments on the first and fifth days. It is suggested that intrapartum hypoxia is an immediate antecedent of newborn irritability. The blood pressure--irritability relationships may therefore reflect the influence of growth retardation, attributable to increased pregnancy blood pressure, and higher labour blood pressure, respectively, on the ability of the fetus to withstand hypoxia and the degree of hypoxia encountered during labour.

A Minority Health Careers Exposure Program.

The University of Tennessee-Memphis (UT-M) Health Careers Exposure Program was initiated in response to the complaint of minority college students that basic medical science laboratories and clinical centers at private and state-supported health-science organizations in Tennessee were inaccessible to them as career-motivating, summer work experiences. The preceptor-apprentice relationship was the means utilized to expose and stimulate minority college students to enter health careers in this study. The formal activity was usually conducted for eight to ten weeks of summer vacation in the basic science and clinical facilities on the UT-M campus.A survey of the current career activities of former apprentices suggests that direct exposure of academically talented, minority college students to health careers is a factor that increases the number entering the health professions.

Efficacy of vital home bleaching.

The nightguard vital bleaching technique has become a very common and accepted procedure for many dental practitioners. Much has been written about the procedure's history, safety and technique; little has been done to quantify the specific color changes of teeth resulting it. This clinical study attempted to give a numerical value to the color change through the use of a light transmission densitometer. The maxillary teeth of twenty-five patients were treated as the control. A significant whitening was observed for a majority of the patients during the four-week duration of the study.