Showing papers by "University of New Mexico published in 1984"

Cisplatin neuropathy. Clinical, electrophysiologic, morphologic, and toxicologic studies

Abstract: Ten of 11 patients with ovarian cancer receiving cisplatin developed a distal sensory neuropathy, manifested early by decreased vibratory sensibility in toes and depressed ankle jerks and later by uncomfortable paresthesias. Eleven patients receiving cisplatin, 50 mg/m2 monthly (mean tstal, 580 mg/m2) were studied prospectively with monthly neurologic examinations and conduction velocity determinations of median, peroneal, and sural nerves. Early signs were decreased vibratory sensibility in toes (mean dose, 417 f 132 mg/m2 [SD]) and loss of ankle jerks (mean dose, 455 f 86 mg/m2). With continued therapy, four developed paresthesias. Strehgth was Unaffected. Sural nerve responses abruptly disappeared in six patients (mean dose, 383 +- 103 mg/m2). Other conduction velocities remain4 sormal. Electron microscopy of peripheral nerves from four patients showed axonal degeneration and secondary myelin breakdown. Platinum concentrations in three patients were similar in tumor (3.3 fig/&, sural nerves (3.5 fig/g), and spinal ganglia (3.8 pg/g), but lower in brain (0.17 fig/&. This may explain the cisplatin toxicity of peripheral nerves with relative sparing of the central nervous system. Cancer 54:1269-1275, 1984. isDiAMiNE DICHLOROPLATINU~~ (cisplatin) has been C used as a cancer chemotherapeutic agent since I 972'.2 and has shown particular efficacy against ovarian, testicular, and bladder cancer^.^ The principle side effects are nephrotoxicity, ototoxicity, nausea and vomiting, and myelos~ppression.~ Scattered reports of peripheral neuropathy associated with cisplatin therapy also have ap~eared.~-'~ The neuropathy was primarily sensory and often the initial symptoms were paresthesias in the feet.4.5.9.10.12.14.15 Mild motor involvement was present in some case^.^.^.' Although most patients improved with cessation of treatment,4,5*10.1 '*13*18 some progressed to severe di~ability.~.~ Previous nerve conduction studies have suggested greater involvement of sensory nerves than motor newes.4.5.9.10.14 Sural nerve biopsies revealed changes interpreted as destruction of myelin in five and

Consensus and controversy

Abstract: The word ’consensus’, of course, is spelled with an ’s’ because it is etymologically related to the words ’consent’ and ’sense’ as in agreeing or having a sense of direction rather than ’census’ or ’cents’ as in counting heads or tossing coins. However, in Alan Davies’s review of Issues in language testing research (ILTR; edited by yours truly, published by Newbury House in 1983), the word ‘consensus’ is about as distant from its correct spelling and etymology as the reviewer is from the facts addressed in ILTR. The contrast between the correct etymology and the erroneous one used three times in the review, is roughly parallel to the fundamental difference in Davies’s approach

Neonatal lung neutrophils and elastase/proteinase inhibitor imbalance

Abstract: Serial bronchoalveolar lavage (BAL) was performed prospectively on 10 normal control subjects, 20 Respiratory Distress Syndrome (RDS), and 11 Bronchopulmonary Dysplasia (BPD) newborn infants to evaluate the role of pulmonary inflammation in neonatal lung disease. Minimal inflammation was found in BAL at less than 24 h of life in all groups, but significant pulmonary polymorphonuclear leukocyte (PMN) influxes were noted at 96 h in RDS and BPD compared with control subjects. By 1 wk of life, BAL PMN counts returned to normal in RDS, but counts remained significantly elevated through 5 wk in BPD. Alveolar macrophage (AM) counts were significantly elevated at 96 h in RDS (p less than 0.05), but were significantly depressed in BPD at 4 and 5 wk (p less than 0.05). The BAL elastase/alpha 1-proteinase inhibitor (alpha 1Pi) ratios in RDS did not differ from those of normal control subjects; however, these ratios were significantly elevated from 1 through 4 wk of life in BPD, placing these infants at risk for proteolytic lung damage. Lavage elastase levels were elevated in both RDS and BPD, associated with a parallel increase in BAL alpha 1Pi in RDS and depressed BAL alpha 1Pi in BPD. These findings suggest that pulmonary inflammation, associated with a prolonged PMN influx and an imbalance between elastase and alpha 1Pi, may contribute to the development of the neonatal chronic lung disease, BPD.

Sexual selection and sexual differences in mormon crickets (orthoptera: tettigoniidae, anabrus simplex).

Abstract: Darwin (1871) suggested that differences in the intensity of sexual selection on the sexes was a cause of secondary sexual differences. He proposed that behavioral and morphological traits possessed by males had evolved in the context of sexual competition, because fertilizable females are typically in short supply. Emlen and Oring (1977) pointed to several factors that are expected to change the ratio of fertilizable females to sexually active males (the operational sex ratio) and thus, the intensity of sexual selection on the sexes; theoretically both the investment of the sexes in offspring (parental investment; Trivers, 1972) and certain features of the social and physical environment are important. Parental investment theory (Trivers, 1972) predicts that females in species where males invest most in individual offspring should exhibit typically masculine traits by competing for access to sexually active males and males should exhibit typically feminine traits by being selective of mates. In vertebrate species where males provide the majority of parental care there is good evidence for a role-reversal in courtship behavior (Wittenberger, 1979; Petrie, 1983). In insects, paternal care of eggs and offspring is rare (Smith, 1980) but males of several groups supply their mates with nutritious prey items or glandular products (Thornhill, 1976a). These male efforts represent mating effort, as they apparently function in acquiring copulations (Alexander and Borgia, 1979). They are, however, "nonpromiscuous" mating efforts, potentially able to limit female reproduction (Thormhill, 1976b; Gwynne, 1984a) and thus are expected to influence the evolution of sexual differences in a similar way to male parental investment (Gwynne, 1984b). Males of many katydids (Orthoptera: Tettigoniidae) feed their mates with a large spermatophore which enhances female reproduction (Gwynne, 1984a). Mormon cricket males (Anabrus simplex Haldeman) produce a large spermatophore (Gillette, 1904), investing some fifth of their body weight in a single mating. I reported a reversal in the typical courtship roles for this species; females competed for access to singing males and males discriminated among females by selecting heavier individuals as mates (Gwynne, 1981). Here I show that this courtship rolereversal is found at certain sites but not at others. I examine sexual selection and its consequences at different sites by (1) testing the prediction that sexual selection on females, as estimated by variance in mating success, should be greater at sites where sexual competition among females is observed, (2) detailing the differences in courtship behavior between sites that have apparently resulted from differences in sexual selection, (3) testing the prediction that female body size should be greater at role-reversed sites as a consequence of intersexual selection for larger females, and (4) describing possible environmental differences between sites that have caused interpopulation variation in sexual differences.

Ion-assisted deposition of optical thin films: low energy vs high energy bombardment

Abstract: Oxygen ion-assisted deposition of SiO2 and TiO2 has been investigated as a function of ion energy (30–500 eV) and current density (0–300 μA/cm2) at the optic. It is shown that both low and high energy ion bombardment improve SiO2 film stoichiometry, although slightly greater improvement is realized for the low energy case. For TiO2 films, low energy bombardment improves stoichiometry, while high energy bombardment is clearly detrimental. A reduction in H content by a factor of 10 is observed in SiO2 films deposited with high energy ion bombardment. Durable films are produced at low substrate temperatures (50–100°C). Film stress characteristics are discussed.

Gradual and Abrupt Shifts in Ocean Chemistry During Phanerozoic Time

Abstract: The clearest records of changes in chemistry of the exogenic cycle are found in mineral inventories (NaCl, CaSO4, Ccarb, Corg, P), isotope ratios (δ34Ssft, δ13Ccarb, 87Sr/86Srcarb,87Sr/86Srapt), 87Sr/86Srapt), and trace elements (Ce/Laaptand heavy metals in black shales) vs. age. While these variations can be simplistically modelled in the long-term to confine all variations to the larger sedimentary reservoirs, there are several reasons to assert that some of the variability is internal to the smaller oceanic (and atmospheric) reservoirs, especially for short-term events. These are controlled by complex feedback loops, perhaps ultimately forced by plate-tectonic activity cycles. Many links are only speculative.

Diffusional Effects in the Recovery of Methane From Coalbeds

Abstract: This paper presents evidence that the unipore model is inadequate for describing diffusional fluxes from coal over the entire timescale of desorption. Field desorption of methane from coal pieces shows pronounced curvature, which is attributable to the bidisperse pore structure generally found for coal. A model is presented that accounts for the bidisperse pore structure of coal and predicts diffusion rates for both field and laboratory desorptions. Transient diffusivities are determined for Pittsburgh bituminous and Madrid (NM) anthracite coals by using a pulse tracer technique coupled with Fourier analysis of the elution curves. This technique allows the rapid determination of the diffusion parameters with minimal experimental effort. In addition, steady-state diffusivities are determined to identify mechanisms of diffusion. Diffusion was found to be a combination of bulk, Knudsen, and surface diffusions, depending on the coal pore structure and gas pressure.

The ergodic theory of Markov chains in random environments

Abstract: A general formulation of the stochastic model for a Markov chain in a random environment is given, including an analysis of the dependence relations between the environmental process and the controlled Markov chain, in particular the problem of feedback. Assuming stationary environments, the ergodic theory of Markov processes is applied to give conditions for the existence of finite invariant measure (equilibrium distributions) and to obtain ergodic theorems, which provide results on convergence of products of random stochastic matrices. Coupling theory is used to obtain results on direct convergence of these products and the structure of the tail σ-field. State properties including classification and communication properties are discussed.

The variability of holocene climate change: evidence from varved lake sediments.

Abstract: Varved sediments from a lake near the present forest-prairie border in northwestern Minnesota provide an annual record of climate change for the last 10,400 years. Climate-sensitive mineral, chemical, and biological components show that the mid-Holocene dry interval between 8500 and 4000 years ago is asymmetrical and actually consists of two distinct drier pulses separated by a moister interval that lasted about 600 years. Cyclic fluctuations with periods of several hundred years were abrupt and persistent throughout the Holocene and are most clearly recorded within the two drier pulses.

Combination rule for redundant information in reaction time tasks with divided attention

Abstract: Five choice reaction time experiments were conducted to investigate the redundant-signals effect in letter identification. In two experiments, displays were large letters formed by small letters. Three experiments used simple two-letter displays with different spatial arrangements. Data were analyzed by the measurement model of variable criterion theory. In all experiments, throughout the RT distributions, the strength of the redundant signals condition was an extremely precise linear function of the sum of the strengths of the separate components. Each stimulus component contributed about one-half of its strength. The form of the distribution was entirely determined by this additive relation. However, the superiority of the redundant-signals condition is not produced by this summation, but by an additive constant present throughout the distribution. It is suggested that this represents a decrement produced by a distractor in a relevant location in single-target conditions. The results strongly favor strength theory as opposed to separate activation models that account for the redundant-signals effect by statistical facilitation. Additional information provided concerns the global precedence effect and S-R compatibility.

PEG-modified antibody with reduced affinity for cell surface Fc receptors

Abstract: PEG-modified protein molecules characterized by reduced immunogenicity are prepared by covalent modification of the protein with PEG employing an active ester intermediate. Antibodies so modified exhibit decreased binding capacity for Fc cell surface receptors, are non-toxic and retain full antigen binding activity, and are consequently useful in a variety of immunologically-based diagnostic and therapeutic procedures.

Quantization of electrodynamics in nonlinear dielectric media

Abstract: We point out some problems with the usual quantum-mechanical theory of electrodynamics in nonlinear dielectric media which is used in nonlinear optics. In order to understand these problems, the Hamiltonian formulation of the theory is examined. It is found that many of the difficulties in the usual theory are a result of the fact that the canonical momentum for the interacting theory is not the same as that for the free electromagnetic field theory.

Pathogenesis and prevention of necrotizing enterocolitis: a hypothesis based on personal observation and a review of the literature.

Abstract: The hypothesis is, that necrotizing enterocolitis (NEC) of the neonate occurs by the coincidence of two of three pathologic events: (1) intestinal ischemia, (2) colonization by pathogenic bacteria, and (3) excess protein substrate in the intestinal lumen. NEC is more likely to appear following quantitative extremes, ie, severe ischemia highly pathogenic flora, or marked excess of substrate. NEC develops only if a threshold of injury, sufficient to initiate intestinal necrosis, is exceeded. The hypothesis is derived from previous theories by Santulli, which implicated all three events, and by Lawrence, in which a single event, abnormal bacterial colonization, was considered sufficient to induce NEC. This hypothesis may explain both typical occurrences of NEC among high-risk premature infants in neonatal intensive care units (NICUs), and atypical occurrences among infants considered at low-risk, eg, previously healthy term infants, infants fed breast milk exclusively, and infants never fed. It may further explain why NEC fails to develop in most high-risk infants in NICUs. Preventive measures might include: (1) pharmacologic stabilization of intestinal perfusion, (2) modification of the intestinal flora, or (3) feeding colostrum or other protective substances. Each theoretical benefit is accompanied by potential risks. The prevention of NEC may require favorable intervention in two of the three pathologic events.

Folate and Vitamin B12 Status in a Healthy Elderly Population

Abstract: Folic acid and vitamin B12 nutritional status was examined in a group of 270 healthy elderly individuals using both dietary and biochemical measures. Of these 40 per cent had dietary intakes of folic acid that were less than half the recommended dietary allowance of 400 micrograms/day, and 13 per cent had intakes of less than half the recommended dietary allowance for vitamin B12 (3 micrograms/day). However, only 8 per cent had low plasma folates (less than 3.0 ng/ml) and only 3 per cent had RBC folates less than 140 ng/ml. Plasma true cobalamin levels less than 220 pg/ml were found in 3 per cent. None of these individuals showed any clinical signs of folate and/or vitamin B12 deficiency, and mean corpuscular volumes were not significantly greater than those for the entire population (90.8 +/- 4.1 fl). The correlations of intakes of folic acid and vitamin B12 with plasma or erythrocyte levels were moderate (about 0.5). It was also clear that those taking supplements had significantly greater blood levels than those not taking supplements, although the benefit of higher plasma or erythrocyte levels of these nutrients is not clear. The data indicate that folate and vitamin B12 status in free-living healthy elderly is not a major medical problem.