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2'-Carboxyarabinitol 1-phosphate (CA1P) is a naturally occurring inhibitor of ribulose-1,5 bisphosphate carboxylase/oxygenase activity. A chloroplast phosphatase has previously been identified that degrades CA1P in vitro to carboxyarabinitol (CA) plus phosphate, but CA has not yet been detected in plants. Here, we detail procedures to isolate and assay CA from leaves and utilize mass spectrometry to demonstrate for the first time that CA is present in plants. CA was present in leaves of all 13 species examined, including those of C(3), C(4), and Crassulacean acid metabolism photosynthetic subgroups. CA was present both in species with high levels of CA1P (e.g. Phaseolus vulgaris, Lycopersicon esculentum, Beta vulgaris) as well as in species with low levels of CA1P (e.g. Spinacea oleracea, Triticum aestivum). CA levels in the light were sometimes greater than those in the dark. Bean leaves had the most CA of any species tested, with levels in the light approaching 1 micromole per milligram of chlorophyll. In illuminated bean leaves, about 63% of the CA is located outside the chloroplast. CA is one of only a few branched chain sugar acids to be identified from plants.

Results presented here indicate that 2'-carboxyarabinitol (CA) is the in vivo precursor and product of 2'-carboxyarabinitol 1-phosphate (CA1P) metabolism in leaves. When [2-(14)C]CA was fed in the light to leaves of five species known to be highly active in CA1P metabolism (Phaseolus vulgaris, Lycopersicon esculentum, Helianthus annuus, Petunia hybrida, and Beta vulgaris), [(14)C]CA1P was formed in the dark. Reillumination of a Phaseolus leaf caused this [(14)C]CA1P to be rapidly metabolized to [(14)C]CA (t((1/2)) = 1 min). The epimer 2'-carboxyribitol could not substitute for CA in the dark synthesis of CA1P, and CA in the anionic form was a better substrate than CA in the lactone form. In leaves of Phaseolus vulgaris, the active CA pool size used in the dark synthesis of CA1P is between about 70 and 110 nanomoles per milligram of chlorophyll. The photosynthetic electron transport inhibitor diuron did not affect the dark synthesis of [(14)C]CA1P, but did greatly reduce the rate of its subsequent light degradation (t((1/2)) = approximately 10 min). Dark synthesis of [(14)C]CA1P was inhibited by dithiothreitol and NaF. From the present data, we suggest that CA1P and CA participate in a metabolic substrate cycle in vivo.

Since the dichotic listening technique was first described (Broadbent, 1954; Kimura, 1961), researchers have been interested in its ability to document hemispheric dominance for language and other functions in a noninvasive fashion. Numerous articles have been published using normal healthy subjects as well as others using patients who have suffered neurological disease or damage. Much controversy has been generated over the use of dichotic listening in the latter population, however, since unilateral brain lesions might be expected to alter normal perception. This paper responds to one recently published by Niccum and Speaks (1991) that attempted to explain why a lesion effect, and not hemispheric reorganization, is the best explanation for findings of left-ear advantage in recovering aphasics.

Neuropsychological outcome of 28 patients with brain tumors diagnosed before the age of 36 months (mean, 19 months) was assessed using a comprehensive battery of tests. Elapsed time between diagnosis and testing averaged 6.2 years. Half the patients had received cranial radiation therapy and surgery, with and without chemotherapy, whereas the rest had received only surgery, with or without chemotherapy. Groups were comparable with respect to tumor diagnosis and location, age at diagnosis, race, and sex. Intellectual functioning was significantly lower in children whose treatment included cranial irradiation than in those treated without cranial irradiation, and this effect was more pronounced in nonverbal than in verbal intellectual abilities. Mean scores for the radiation group were lower than for the no-radiation group in all areas assessed and were significantly below age-based normative means in five of the eight cognitive areas: intellectual, memory, attention, motor, and visual-spatial skills. Mean scores for children in the no-radiation group were generally within the average range in all cognitive areas except visual-spatial skills, which were significantly below age-based normative means. Endocrine deficiencies and growth retardation were much more prevalent in patients treated with cranial irradiation. Because the immature brain is susceptible to treatment-related pathologic changes, infants are at greater risk than older children for significant, long-term neuropsychological, endocrine, and growth sequelae. In children treated without cranial irradiation, morbidity was minimized without an increased rate of mortality.

The level of 2-carboxyarabinitol 1-phosphate (CA1P) in leaves of 12 species was determined by an isotope dilution assay. (14)C-labeled standard was synthesized from [2-(14)C]carboxyarabinitol 1,5-bisphosphate using acid phosphatase, and was added at the initial point of leaf extraction. Leaf CA1P was purified and its specific activity determined. CA1P was found in dark-treated leaves of all species examined, including spinach (Spinacea oleracea), wheat (Triticum aestivum), Arabidopsis thaliana, and maize (Zea mays). The highest amounts were found in bean (Phaseolus vulgaris) and petunia (Petunia hybrida), which had 1.5 to 1.8 moles CA1P per mole ribulose 1,5-bisphosphate carboxylase catalytic sites. Most species had intermediate amounts of CA1P (0.2 to 0.8 mole CA1P per mole catalytic sites). Such intermediate to high levels of CA1P support the hypothesis that CA1P functions in many species as a light-dependent regulator of ribulose 1,5-bisphosphate carboxylase activity and whole leaf photosynthetic CO(2) assimilation. However, CA1P levels in spinach, wheat, and A. thaliana were particularly low (less than 0.09 mole CA1P per mole catalytic sites). In such species, CA1P does not likely have a significant role in regulating ribulose 1,5-bisphosphate carboxylase activity, but could have a different physiological role.

We report on the neuropsychological status of 31 children with primary brain tumors who underwent assessment before receiving therapy. Overall, the children performed within normal limits in all test areas. The exception was the group with anterior hemispheric tumors who demonstrated deficits in executive cognitive functions. Also, when compared according to tumor type, children with midline tumors and hydrocephalus performed more poorly than others on measures of intelligence, executive abilities, visual-motor skills, and fine-motor functions. Although one-half to two-thirds of the children with supratentorial midline and infratentorial tumors had cranial nerve, oculomotor, or cerebellar deficits, only the latter were associated with specific neuropsychological deficits (poorer performance on fine-motor and visual-motor tests). Age did not appear to be a factor in these children's neuropsychological test performances.

Metabolism of 2'-carboxy-D-arabinitol 1-phosphate (CA1P) is an important component in the light-dependent regulation of ribulose-1,5-bisphosphate carboxylase (Rubisco) activity and whole leaf photosynthetic CO2 assimilation in many species, and functions as one mechanism for regulating Rubisco activity when photosynthesis is light-limited. Species differ in their capacity to accumulate CA1P, ranging from those which can synthesize levels of this compound approaching or in excess of the Rubisco catalytic site concentration, to those which apparently lack the capacity for CA1P synthesis. CA1P is structurally related to the six carbon transition state intermediate of the carboxylation reaction and binds tightly to the carbamylated catalytic site of Rubisco, making that site unavailable for catalysis. Under steady-state, the concentration of CA1P in the leaf is highest at low photon flux density (PFD) or in the dark. Degradation of CA1P and recovery of Rubisco activity requires light and is stimulated by increasing PFD. The initial degradation reaction is catalyzed by an enzyme located in the chloroplast stroma, CA1P phosphatase, which yields carboxyarabinitol (CA) and inorganic phosphate as its products. The pathway of CA metabolism in the plant remains to be determined. Synthesis of CA1P occurs in the dark, and in Phaseolus vulgaris this process has been shown to be stimulated by low PFD. The pathway of CA1P synthesis and its relationship to the degradative pathway remains unknown at the present time. The discovery of the existence of this previously unknown carbon pathway in photosynthesis indicates that we still have much to learn concerning the regulation of Rubisco activity and photosynthesis.

Extracellular recordings were made from 29 spinoreticular cells in the spinal cords of anesthetized monkeys. The cells were in either the cervical or the lumbar enlargement, and they were identified by antidromic activation from the medial part of the pontomedullary reticular formation. More spinoreticular neurons were sampled in the cervical than in the lumbar cord. Most of the cells were contralateral to the side from which antidromic activation was observed, but a higher proportion of the spinoreticular neurons in the cervical enlargement than in the lumbar enlargement was ipsilateral to the antidromic stimulus. Three cells in the lumbar cord were antidromically activated not only from the reticular formation but also from the contralateral thalamus, confirming that some spinoreticular projections are formed by collaterals from spinothalamic cells. Most of the spinoreticular neurons were in the ventral horn in laminae VII and VIII, although a few were in laminae IV-VI. Nearly half of the spinoreticular cells in the sample could not be activated by any form of peripheral stimulation tested. The other cells could be activated by stimulation of receptive fields that varied from small to large, that were sometimes bilateral regions of the skin or deep tissues. Although some spinoreticular cells could be classified as low threshold or wide dynamic range, the largest proportion were high threshold, requiring noxious stimulation for their activation. Descending volleys resulting from stimulation in the reticular formation could often be shown to inhibit or to excite spinoreticular neurons. It can be concluded that at least some spinoreticular neurons may play a role in nociception.

Characteristics of C(4) photosynthesis were examined in young, mid-age, and mature leaves of Flaveria trinervia (an NADP-malic enzyme-type C(4) dicot). The turnover of [4-(14)C] (malate plus aspartate) following a pulse with (14)CO(2) was similar in leaves of different ages (apparent half-time of 18-25 seconds). However, the rate of (14)CO(2) incorporation in mid-age leaves was about 1.5-fold higher than in young leaves, and about 2.5-fold higher than in mature leaves. The rate of (14)CO(2) fixation was proportional to the total active pool of malate plus aspartate but was not correlated with the total photosynthetically derived inorganic carbon pool. The leaf's ability to concentrate inorganic carbon photosynthetically declined during leaf expansion, from 29 down to 7 nanomoles per milligram chlorophyll. Similarly, the active aspartate pool also declined during leaf expansion, from about 123 down to 20 nanomoles per milligram chlorophyll. Enhanced metabolism of aspartate to CO(2) and pyruvate in young leaves is suggested to facilitate the maintenance of high CO(2) levels in bundle sheath cells which are thought to have a higher conductance to CO(2).

Twelve infants with unilateral congenital cataracts treated at Boston Children's Hospital between 1978 and 1986 have now reached the age of 3.5 years or older. All infants had cataract extractions, aphakic contact lens fitting, and occlusion of the unaffected eye by 6 months of age. Patients with posterior lenticonus or persistent hyperplastic primary vitreous were excluded from this review. Early improvement of visual acuity in the aphakic eye was monitored by preferential looking tests, and occlusion of the sound eye was adjusted accordingly. E card visual acuities are now available on all 12 children. Five patients have 20/70 or better visual acuity, three patients have between 20/100 and 20/400 vision, and four patients have less than 20/400 in the aphakic eye. Two patients whose cataract surgery was done after 4 months of age had the poorest visual results. Difficulty maintaining occlusion therapy and interruptions of contact lens wear limited the development of better vision in some patients. The visual results to date in these 12 patients suggest that early aggressive treatment of unilateral congenital cataracts is worthy of consideration in most instances.

Light microscopic examination of leaf cross-sections showed that Flaveria brownii A. M. Powell exhibits Kranz anatomy, in which distinct, chloroplast-containing bundle sheath cells are surrounded by two types of mesophyll cells. Smaller mesophyll cells containing many chloroplasts are arranged around the bundle sheath cells. Larger, spongy mesophyll cells, having fewer chloroplasts, are located between the smaller mesophyll cells and the epidermis. F. brownii has very low CO(2) compensation points at different O(2) levels, which is typical of C(4) plants, yet it does show about 4% inhibition of net photosynthesis by 21% O(2) at 30 degrees C. Protoplasts of the three photosynthetic leaf cell types were isolated according to relative differences in their buoyant densities. On a chlorophyll basis, the activities of phosphoenolpyruvate carboxylase and pyruvate, Pi dikinase (carboxylation phase of C(4) pathway) were highest in the larger mesophyll protoplasts, intermediate in the smaller mesophyll protoplasts, and lowest, but still present, in the bundle sheath protoplasts. In contrast, activities of ribulose 1,5-bisphosphate carboxylase, other C(3) cycle enzymes, and NADP-malic enzyme showed a reverse gradation, although there were significant activities of these enzymes in mesophyll cells. As indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the banding pattern of certain polypeptides of the total soluble proteins from the three cell types also supported the distribution pattern obtained by activity assays of these enzymes. Analysis of initial (14)C products in whole leaves and extrapolation of pulse-labeling curves to zero time indicated that about 80% of the CO(2) is fixed into C(4) acids (malate and aspartate), whereas about 20% of the CO(2) directly enters the C(3) cycle. This is consistent with the high activity of enzymes for CO(2) fixation by the C(4) pathway and the substantial activity of enzymes of the C(3) cycle in the mesophyll cells. Therefore, F. brownii appears to have some capacity for C(3) photosynthesis in the mesophyll cells and should be considered a C(4)-like species.

This paper discusses the role of developmental assessment within the EPSDT program, describes efforts to develop guides for implementing this component of the program, and summarizes the "developmental review" proposed by the American Association of Psychiatric Services for Children.

Short and long latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded over the contralateral hemisphere. Simultaneously, signals evoked by the same stimulus were monitored at Erb's point. Recordings were made during three conditions which were presented in a different random order to each of the subjects tested. During the control condition the subjects were instructed to attend to and count the number of electrical pulses delivered to the median nerve of their right hand. During the two task conditions, in addition to the pulses, the subjects received stimulation on the dorsal surface of one of their hands. This consisted in drawing circles lightly for the duration of SEP recording using a cotton swab (Q-tip). During the trial, the Q-tip was momentarily withdrawn 15 to 20 times and the subject's task was to ignore the pulses, attend to this cutaneous stimulation and count the number of times the cutaneous stimulation was interrupted. SEPs to the pulse were significantly greater in amplitude when cutaneous stimulation was delivered to the same hand as the pulse (the right hand) than when it was delivered to the left hand. This effect was confined to the long-latency SEPs and did not appear in either the Erb's point response or the short latency SEPs. These data indicate that selective attention to peripheral stimulation is a relatively late process mediated by cortical mechanisms and argue against the notion of early suppression of irrelevant stimulus channels in subcortical centers or in the periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

We conducted a placebo-controlled double-blind investigation in 15 normal volunteers to study the time course of amnesia to auditory stimulation produced by lorazepam. We also studied the relationship between auditory amnesia and auditory evoked potentials to determine if long-latency auditory evoked potentials (LLAEPs) could be utilized as electrophysiologic predictors of memory. Amnesia was produced by administration of 0.05 mg/kg lorazepam intravenously. To separate the changes in LLAEPs due to generalized sedation from those associated with amnestic properties of a drug, a third group of subjects given 1.5 mg/kg secobarbital was included. Observed frequency and duration of amnesia to auditory stimulation after lorazepam was 58% and 3 hours, respectively (mean values), with marked diminuition of antirecall effect at 120 minutes. Administration of lorazepam increased the latency and decreased the amplitude of N1 and P3 components of LLAEPs. These changes appeared to be a result of generalized sedation rather than the amnestic properties of the drug. We failed to find a definite relationship between amnesia and changes in LLAEPs. We conclude that P3 component of LLAEPs cannot be utilized as an electrophysiologic predictor of amnesia in humans.

Forty-two infants who presented to the Children's Hospital in Boston with unilateral congenital cataracts and had cataract surgery by 6 months of age received serial refractions (N = 369) of their aphakic eyes during the first 4 years of life. The 14 patients followed most intensively (185 refractions) showed a rapid decrease in mean spherical equivalent during the first year of life from +30.75 D to +26.36 D, with a less rapid decrease thereafter (24 months, +23.02 D; 36 months, +21.19 D; 48 months, +20.86 D). The rate of change per month decreased from .43 D between 1 and 6 months, .37 D between 6 and 12 months, .30 D between 12 and 18 months, .24 D between 18 and 24 months, and less than .19 D per month thereafter. This study shows that the refractive error of the aphakic eye of patients treated for unilateral congenital cataracts decreases most rapidly during infancy and less rapidly during the next few years of childhood. This information will be helpful in facilitating the treatment of these infants by allowing an approximation of their future contact lens refractive power changes.

Evoked potentials (EPs) to a probe tone stimulus were recorded simultaneously at the temporal and parietal areas of the left and right hemisphere of dextral adults engaged in either an arithmetic or a visuospatial task. The probe EP amplitude was attenuated in the left temporal area during the arithmetic task and in the left temporal and both parietal areas, but significantly more in the right, during the visuospatial task, indicating distinct patterns of regional cerebral engagement for the two types of cognitive activity.

Cortical evoked potentials and dichotic listening test scores were used to assess the extent of activation of the two cerebral hemispheres during various language tasks in a group of 21 recovering aphasics, 15 nonaphasic patients with right-hemisphere stroke, and 17 normal volunteers. In agreement with previous findings, both measures suggest greater right-hemisphere activation during language processing in the recovering aphasics than in nonaphasic patients and normal subjects. These data support the view that restitution of language entails reorganization of brain function with increased participation of the nondominant hemisphere.

Evoked potentials (EPs) to a probe click stimulus were recorded from left and right temporal areas of dextral adults engaged in phonetic and prosodic processing of an emotionally charged tape recorded conversation. Attenuation of the probe EP amplitudes was significantly greater in the left and right hemispheres during the phonetic and prosodic tasks, respectively, indicating lateral dominance shifts depending on selective processing of linguistic vs affective cues conveyed by the same speech signals.

Photosynthesis was examined in leaves of Flaveria brownii A. M. Powell, grown under either 14% or 100% full sunlight. In leaves of high light grown plants, the CO(2) compensation point and the inhibition of photosynthesis by 21% O(2) were significantly lower, while activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and various C(4) cycle enzymes were considerably higher than those in leaves grown in low light. Both the CO(2) compensation point and the degree of O(2) inhibition of apparent photosynthesis were relatively insensitive to the light intensity used during measurements with plants from either growth conditions. Partitioning of atmospheric CO(2) between Rubisco of the C(3) pathway and phosphoenolpyruvate carboxylase of the C(4) cycle was determined by exposing leaves to (14)CO(2) for 3 to 16 seconds, and extrapolating the labeling curves of initial products to zero time. Results indicated that approximately 94% of the CO(2) was fixed by the C(4) cycle in high light grown plants, versus approximately 78% in low light grown plants. Thus, growth of F. brownii in high light increased the expressed level of C(4) photosynthesis. Consistent with the carbon partitioning patterns, photosynthetic enzyme activities (on a chlorophyll basis) in protoplasts from leaves of high light grown plants showed a more C(4)-like pattern of compartmentation. Pyruvate, Pi dikinase and phosphoenolpyruvate carboxylase were more enriched in the mesophyll cells, while NADP-malic enzyme and ribulose 1,5-bisphosphate carboxylase/oxygenase were relatively more abundant in the bundle sheath cells of high light than of low light grown plants. Thus, these results indicate that F. brownii has plasticity in its utilization of different pathways of carbon assimilation, depending on the light conditions during growth.

A probe evoked potentials procedure was used to assess the relative engagement of both cerebral hemispheres during a language task in the following four groups of dextral adults: left hemisphere (LH)-damaged aphasics recovering from stroke, dysarthrics, right hemisphere (RH)-damaged nonaphasic patients, and normal control subjects. In agreement with previous findings using the probe procedure, the present results indicate greater task-specific RH activation in recovering aphasics and, to a lesser degree, dysarthric patients and greater LH activation in both nonaphasic, RH-damaged patients and normal control subjects. On the basis of these data, we suggest that increasing participation of the nondominant hemisphere may subserve restitution of language in adults sustaining LH lesions.

Brainstem auditory evoked potentials (BAEPs) were recorded from rats before and after injection with apamin, a polypeptide component of bee venom. Increased absolute and interpeak latencies were found in Peaks III-VII of the BAEP beginning about 30 minutes after apamin injection suggesting impaired auditory function. No change in BAEP was found when animals were injected with saline or during the baseline period before apamin administration. Results corroborate recent findings from our laboratories of decreased glucose metabolism in brainstem nuclei of the auditory system [3] after injection with the same dose of apamin.

The metabolism of fixed (14)CO(2) and the utilization of the C-4 carboxyl of malate and aspartate were examined during photosynthetic induction in Flaveria trinervia, a C(4) dicot of the NADP-malic enzyme subgroup. Pulse/chase experiments indicated that both malate and aspartate appeared to function directly in the C(4) cycle at all times during the induction period (examined after 30 seconds, 5 minutes and 20 minutes illumination). However, the rate of loss of (14)C-label from the C-4 position of malate plus aspartate was relatively slow after 30 seconds of illumination, compared to treatments after 5 or 20 minutes of illumination. Similarly, the appearance of label in other photosynthetic products (e.g. 3-phosphoglycerate, sugar phosphates, alanine) during the chase periods was generally slower after only 30 seconds of leaf illumination, compared to that after 5 of 20 minutes illumination. This may be due to the lower rate of photosynthesis after 30 seconds illumination. The appearance of label in carbons 1-->3 of each C(4) acid during the chase periods was relatively slow after either 30 seconds or 5 minutes illumination, while there was a relatively rapid accumulation of label in carbons 1-->3 of both C(4) acids after 20 minutes illumination. Thus, while the turnover rate of the (14)C-4 label in both C(4) acids increased only during the first 5 minutes of the induction period, only later during induction is there an increased rate of appearance of label in other carbon atoms of the C(4) acids. The implied source of (14)C for labeling of the 1-->3 positions of the C(4) acids is an apparent carbon flux from 3-phosphoglycerate of the reductive pentose phosphate pathway to phosphoenolpyruvate of the C(4) cycle.

The P-300 component of evoked potentials to a rare tone was measured in normal volunteers and in patients with closed head injuries who either were confused (in posttraumatic amnesia) or had recovered from posttraumatic amnesia and were oriented at the time of recording. The latency of this component, which reflects cortical processing of stimuli, varied reliably, with the degree of orientation being longest for confused patients and shortest for normal subjects. On the basis of these data, we suggest that the P-300 latency can be used as a physiological index of cognitive function in patients with closed head injury.

Intravenous isotope angiography is a rapid, safe, and specific bedside test for confirming brain death by demonstrating the lack of critical cerebral perfusion that occurs in this condition, regardless of etiology. A review of 204 consecutive cases of suspected brain death studied with isotope angiography has reaffirmed our confidence in the specificity of the technique and has convinced us to make less stringent our radiographic criteria for confirming brain death by this method. A technically satisfactory single flow study that shows arrest of the carotid circulation at the base of the skull and absence of the intracranial arterial circulation may be considered confirmatory of a carefully established clinical diagnosis of brain death, even though there may be some visualization of the intracranial venous sinuses. Arbitrary waiting periods, withdrawal of sedative drugs, and electrophysiological studies are not needed when this technique is used.

The potential for C4 photosynthesis was investigated in five C3-C4 intermediate species, one C3 species, and one C4 species in the genus Flaveria, using (14)CO2 pulse-(12)CO2 chase techniques and quantum-yield measurements. All five intermediate species were capable of incorporating (14)CO2 into the C4 acids malate and aspartate, following an 8-s pulse. The proportion of (14)C label in these C4 products ranged from 50-55% to 20-26% in the C3-C4 intermediates F. floridana Johnston and F. linearis Lag. respectively. All of the intermediate species incorporated as much, or more, (14)CO2 into aspartate as into malate. Generally, about 5-15% of the initial label in these species appeared as other organic acids. There was variation in the capacity for C4 photosynthesis among the intermediate species based on the apparent rate of conversion of (14)C label from the C4 cycle to the C3 cycle. In intermediate species such as F. pubescens Rydb., F. ramosissima Klatt., and F. floridana we observed a substantial decrease in label of C4-cycle products and an increase in percentage label in C3-cycle products during chase periods with (12)CO2, although the rate of change was slower than in the C4 species, F. palmeri. In these C3-C4 intermediates both sucrose and fumarate were predominant products after a 20-min chase period. In the C3-C4 intermediates, F. anomala Robinson and f. linearis we observed no significant decrease in the label of C4-cycle products during a 3-min chase period and a slow turnover during a 20-min chase, indicating a lower level of functional integration between the C4 and C3 cycles in these species, relative to the other intermediates. Although F. cronquistii Powell was previously identified as a C3 species, 7-18% of the initial label was in malate+aspartate. However, only 40-50% of this label was in the C-4 position, indicating C4-acid formation as secondary products of photosynthesis in F. cronquistii. In 21% O2, the absorbed quantum yields for CO2 uptake (in mol CO2·[mol quanta](-1)) averaged 0.053 in F. cronquistii (C3), 0.051 in F. trinervia (Spreng.) Mohr (C4), 0.052 in F. ramosissima (C3-C4), 0.051 in F. anomala (C3-C4), 0.050 in F. linearis (C3-C4), 0.046 in F. floridana (C3-C4), and 0.044 in F. pubescens (C3-C4). In 2% O2 an enhancement of the quantum yield was observed in all of the C3-C4 intermediate species, ranging from 21% in F. ramosissima to 43% in F. pubescens. In all intermediates the quantum yields in 2% O2 were intermediate in value to the C3 and C4 species, indicating a co-function of the C3 and C4 cycles in CO2 assimilation. The low quantum-yield values for F. pubescens and F. floridana in 21% O2 presumably reflect an ineffcient transfer of carbon from the C4 to the C3 cycle. The response of the quantum yield to four increasing O2 concentrations (2-35%) showed lower levels of O2 inhibition in the C3-C4 intermediate F. ramosissima, relative to the C3 species. This indicates that the co-function of the C3 and C4 cycles in this intermediate species leads to an increased CO2 concentration at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase and a concomitant decrease in the competitive inhibition by O2.

The purpose of this study was to determine the size and shape of infant eyes having a unilateral congenital cataract. Fourteen infants presenting consecutively with a unilateral congenital cataract were studied. Ages ranged from 1.3 to 6 months (mean 3.7 months). Corneal curvature ranged from 43.00 to 49.50 D (mean 45.6 D). Refractive error at the corneal plane ranged from +23.50 to +34.00 D (mean +28.07 D). The axial length ranged from 16.49 to 20.09 mm (mean 18.41 mm). Microcornea was found in eight infants. There was rapid growth in eye size from normal neonatal dimensions. No significant relation was found among the following: corneal curvature and age; refractive error and age; axial length and age or presence of microcornea; and corneal curvature and refractive error. Corneal vault may be an important factor in fitting contact lenses to aphakic infants. Contact lenses for infants should be designed based on the dimensions of the infant eye.

A dichotic-listening procedure was used to investigate the role of the right hemisphere in recovery from aphasia following left-hemisphere stroke. Thirty-one stroke patients were divided into three groups: (a) patients who were recovering from aphasia (Aphasic group, n = 11), (b) patients who had experienced mild strokes with only transient dysarthria (Dysarthric group, n = 10), and (c) patients who had sustained right-hemisphere stroke with no language disturbance (Nonaphasic group, n = 10). In addition, a group of normal, healthy volunteers served as a control group (n = 11). Results show that, like the Control subjects, the Dysarthrics and Nonaphasics showed a strong right-ear advantage (REA) for dichotically presented consonant-vowel (CV) syllables. This is usually thought to be an indication of left-hemisphere dominance (Kimura, 1961). By contrast, the Aphasic group showed left-ear advantage (LEA) suggesting a shift in cerebral dominance for language. The possibility that the results were due to sensory degradation of the auditory messages (lesion effect) was explored. This idea was rejected in favor of an explanation based on increased right-hemisphere mediation of language following left-hemisphere aphasiogenic lesions.

The weedy species Parthenium hysterophorus (Asteraceae) possesses a Kranz-like leaf anatomy. The bundle sheath cells are thick-walled and contain numerous granal chloroplasts, prominent mitochondria, and peroxisomes, all largely arranged in a centripetal position. Both mesophyll and bundle sheath chloroplasts accumulate starch. P. hysterophorus exhibits reduced photorespiration as indicated by a moderately low CO(2) compensation concentration (20-25 microliters per liter at 30 degrees C and 21% O(2)) and by a reduced sensitivity of net photosynthesis to 21% O(2). In contrast, the related C(3) species P. incanum and P. argentatum (guayule) lack Kranz anatomy, have higher CO(2) compensation concentrations (about 55 microliters per liter), and show a greater inhibition of photosynthesis by 21% O(2). Furthermore, in P. hysterophorus the CO(2) compensation concentration is relatively less sensitive to changes in O(2) concentrations and shows a biphasic response to changing O(2), with a transition point at about 11% O(2). Based on these results, P. hysterophorus is classified as a C(3)-C(4) intermediate. The activities of diagnostic enzymes of C(4) photosynthesis in P. hysterophorus were very low, comparable to those observed in the C(3) species P. incanum (e.g. phosphoenolpyruvate carboxylase activity of 10-29 micromoles per milligram of chlorophyll per hour). Exposures of leaves of each species to (14)CO(2) (for 8 seconds) in the light resulted in 3-phosphoglycerate and sugar phosphates being the predominant initial (14)C products (77-84%), with

Utilization of reserve lipid and carbohydrates during germination (0-12 h) and postgerminative growth (12-48 h) was studied in cotton (Gossypium hirsutum L.) seedlings. Raffinose and stachyose were utilized during the germination period and early growth; mobilization was associated with α-galactosidase (EC 3.2.1.22) activity. Results from pulse-chase experiments with [(3)H]raffinose supplied exogenously to 4-h soaked seeds indicated that raffinose-derived catabolites contributed to the coincident increase in cotyledon sucrose and starch, and to the small increase in axis dry weight. Starch appears to be an alternative sink for end products of hydrolysis of reserve carbohydrates prior to the onset of rapid axis growth and cotyledon expansion. Mobilization of neutral lipid commenced at about 16 h after soaking, concomitant with development of key glyoxylate-cycle and other gluconeogenesis-related enzyme activities. Axis dry weight increased three-fold between 24 and 48 h. Results from pulse-chase (3 h, 16 h) experiments in which [2-(14)C]acetate was supplied to cotyledons of intact 22-h-old seedlings showed that acetate-derived metabolites were not transported exclusively to the axes, but were partitioned between axes and cotyledons. Only 27% of total incorporated radioactivity was recovered in axes following the chase, 18% was evolved as CO2, and the rest was recovered in water-soluble substances (20%) and polymers (31%) within the cotyledons. Of the polymers, 55% of the activity was in polysaccharides (Starch, pectic substances, hemicellulose, cellulose), 25% in protein, and 20% in unidentified neutral and acidic compounds. Considering these data, the amount of lipid mobilized, and various routes by which supplied [2-(14)C]acetate could be metabolized, it appears that lipidderived compounds contribute only 25-40% of axis dry-weight gain. Lipid-derived substances retained in the cotyledons likely are utilized for expansion and differentiation of the cotyledons into photosynthetic organs.

Labeling patterns from (14)CO(2) pulses to leaves and whole leaf metabolite contents were examined during photosynthetic induction in Flaveria trinervia, a C(4) dicot of the NADP-malic enzyme subgroup. During the first one to two minutes of illumination, malate was the primary initial product of (14)CO(2) assimiltion (about 77% of total (14)C incorporated). After about 5 minutes of illumination, the proportion of initial label to aspartate increased from 16 to 66%, and then gradually declined during the following 7 to 10 minutes of illumination. Nutrition experiments showed that the increase in (14)CO(2) partitioning to aspartate was delayed about 2.5 minutes in plants grown with limiting N, and was highly dampened in plants previously treated 10 to 12 days with ammonia as the sole N source. Measurements of C(4) leaf metabolites revealed several transients in metabolite pools during the first few minutes of illumination, and subsequently, more gradual adjustments in pool sizes. These include a large initial decrease in malate (about 1.6 micromoles per milligram chlorophyll) and a small initial decrease in pyruvate. There was a transient increase in alanine levels after 1 minute of illumination, which was followed by a gradual, prolonged decrease during the remainder of the induction period. Total leaf aspartate decreased initially, but temporarily doubled in amount between 5 and 10 minutes of illumination (after its surge as a primary product). These results are discussed in terms of a plausible sequence of metabolic events which lead to the formation of the intercellular metabolite gradients required in C(4) photosynthesis.