Measurement and modelling of air pollution and atmospheric chemistry in the U.K. West Midlands conurbation: overview of the PUMA Consortium project.

The PUMA (Pollution of the Urban Midlands Atmosphere) Consortium project involved intensive measurement campaigns in the Summer of 1999 and Winter of 1999/2000, respectively, in which a wide variety of air pollutants were measured in the UK West Midlands conurbation including detailed speciation of VOCs and major component analysis of aerosol. Measurements of the OH and HO2 free radicals by the FAGE technique demonstrated that winter concentrations of OH were approximately half of those measured during the summer despite a factor of 15 reduction in production through the photolysis of ozone. Detailed box modelling of the fast reaction chemistry revealed the decomposition of Criegee intermediates formed from ozone-alkene reactions to be responsible for the majority of the formation of hydroxyl in both the summer and winter campaigns, in contrast to earlier rural measurements in which ozone photolysis was predominant. The main sinks for hydroxyl are reactions with NO2, alkenes and oxygenates. Concentrations of the more stable hydrocarbons were found to be relatively invariant across the conurbation, but the impacts of photochemistry were evident through analyses of formaldehyde which showed the majority to be photochemical in origin as opposed to emitted from road traffic. Measurements on the upwind and downwind boundaries of the conurbation revealed substantial enhancements in NOx as a result of emissions within the conurbation, especially during westerly winds which carried relatively clean air. Using calcium as a tracer for crustal particles, it proved possible to reconstruct aerosol mass from the major chemical components with a fairly high degree of success. The organic to elemental carbon ratios showed a far greater influence of photochemistry in summer than winter, presumably resulting mainly from the greater availability of biogenic precursors during the summer campaign. Two urban airshed models were developed and applied to the conurbation, one Eulerian, the other Lagrangian. Both were able to give a good simulation of concentrations of both primary and secondary pollutants at urban background locations.

ME491 melanoma-associated glycoprotein family: antigenic identity of ME491, NKI/C-3, neuroglandular antigen (NGA), and CD63 proteins.

BACKGROUND: Numerous monoclonal antibodies (MAbs) have been produced to antigens found in human melanomas. Three of the best characterized melanoma antigens include the melanoma-associated glycoproteins (MAGs) defined by two reagent families--the ME491 family (including ME491, 8-1H, and 8-2A) and the NKI/C-3 family (including NKI/C-3 and NKI/black-13)--as well as the neuroglandular antigen (NGA) defined by MAbs LS59, LS62, and LS140. These three antigens have significant similarities in tissue distribution, biosynthesis, and structure. The ME491 MAG has been cloned, mapped, and sequenced. Numerous non-melanoma-associated proteins (Sm23, CO-029, R2, TAPA-1, CD9, CD37, CD53, and CD63) have recently been shown to have significant homology to this sequence. PURPOSE: We conducted this study to investigate the similarity between the two MAG antigens and NGA. METHODS: Several reagents defining the three different melanoma antigens were compared, using competition immunoprecipitation, immunoassay, and inhibition radioimmunoassay techniques. RESULTS: Immunoassay experiments show that MAbs defining the three melanoma antigens bind to affinity-purified ME491 antigen and inhibit each other from binding in an inhibition radioimmunoassay. Competition immunoprecipitation experiments demonstrate that the ME491 and NKI/C-3 antibodies bind to NGA. Rabbit anti-ME491 idiotype serum recognizes determinants shared by NKI/C-3 and the anti-NGA MAbs. A competition immunoprecipitation experiment also confirms the identity of CD63, as defined by MAb RUU-SP 2.28, with the three melanoma antigens. CONCLUSION: These data indicate that the MAGs defined by ME491 and NKI/C-3 as well as the anti-NGA antibodies are epitopes of the same molecule, which is identical to CD63 by both immunochemical and molecular genetic investigations. IMPLICATIONS: Our results indicate that the data obtained in studies of these three melanoma antigens may be pooled, and we propose that the molecule recognized by these reagents be classified as CD63.

NMR studies of intracellular water at 300 MHz: T2-specific relaxation mechanisms in synchronized or EGF-stimulated cells.

Responses specific to the spin-spin relaxation time (T2) have been observed in two time-dependent studies of the intracellular water in normal and transformed Syrian hamster fetal fibroblasts. At 300-MHz (7.0 T), the spin-lattice relaxation time (T1) was insensitive to several aspects of cellular physiology that produced changes in the T2 and the apparent self-diffusion coefficient (Dapp) of intracellular water. In normal cells stimulated with epidermal growth factor (EGF), T1 was insensitive to time-dependent changes detected by T2 and Dapp. In synchronized tumor cells, T1 was insensitive to cell-cycle-dependent changes detected by T2. The strongly coupled behavior of T2 and Dapp that was observed as a function of time in EGF-stimulated cells indicates that the diffusion of intracellular water through inhomogeneous local magnetic field gradients produced effects observable in T2. Conformational changes in large intracellular macromolecular assemblies such as chromatin or the cytoskeleton may alter the magnitude and inhomogeneity of local field gradients, producing responses in T2 and Dapp only.

DNA replication in Syrian hamster cells transiently exposed to hydroxyurea.

DNA rereplication has been observed in mammalian cells transiently treated during S phase with hydroxyurea, an inhibitor of DNA synthesis. Recently, evidence has been presented which does not support this proposal. We have performed a series of similar but more defined studies with the tumorigenic Syrian hamster cell line BP6T to further investigate the possibility of DNA rereplication after transient inhibition during S phase. Synchronized BP6T cells (greater than 75%) were given a 6-h exposure to 1 mM hydroxyurea after having progressed 2 h into S phase. The DNA species synthesized up to 24 h after removal of the inhibitor have been identified by bromodeoxyuridine pulse labeling and density gradient centrifugation studies. The results indicate that no DNA rereplication had occurred in the S phase of the same cell cycle as the transient hydroxyurea treatment. DNA replicated early in the S phase in which treatment was given was not replicated again until the next cell cycle. Our observations reveal that DNA rereplication does not occur in tumorigenic Syrian hamster cells transiently insulted with hydroxyurea during S phase. Thus, these findings imply that DNA synthesis is stringently controlled in these transformed cells.

A biopsychosocial approach to treating patients with affective disorders.

The authors describe the development of an affective disorders consultation service that implemented a biopsychosocial model of subspecialty consultation within a university-affiliated community mental health center. They retrospectively analyzed the first 2 years of consultations, assessing the process of consultation and examining patterns of consultee inquiries and consultation recommendations. Consultants recommended combined psychopharmacologic and psychodynamic therapies for most patients and found psychodynamic psychotherapy strikingly overlooked by consultees, all of whom were psychiatrists or other mental health professionals. This evaluation documents the psychiatric consultees' deemphasis of the biopsychosocial perspective in clinical practice.

Evidence that the antitumor agent hydroxyurea enters mammalian cells by a diffusion mechanism.

Very little information is available about the process responsible for the uptake of the antitumor agent hydroxyurea by mammalian cells. Therefore we have investigated the transport of hydroxy[14C]-urea into Chinese hamster ovary cells. Using a convenient and reproducible 2 min. assay we found that hydroxyurea was taken up in a linear nonsaturable fashion between 0.01 mM and 100 mM drug. The Km for hydroxyurea uptake was essentially zero and the Vmax appeared to be infinite, suggesting a diffusion mechanism. The observation that intracellular drug concentrations were consistently less than medium concentrations indicated that uptake was not an active process. Experiments performed with the metabolic inhibitor sodium azide, and investigations at different assay temperatures also gave results consistent with a mechanism of drug diffusion. In total, the results obtained in this study are in agreement with the proposal that hydroxyurea enters the cell primarily by a process of diffusion. These observations provide a more complete understanding of the mode of action of this widely used drug.

Ribonucleotide reductase: an intracellular target for the male antifertility agent, gossypol.

Gossypol is a yellow phenolic compound which reversibly inhibits spermatogenesis making it one of the few effective male antifertility drugs. The cytotoxic effects of gossypol have been associated with its ability to irreversibly inhibit DNA synthesis by a previously unknown mechanism. The results of this study indicate that gossypol is a potent inhibitor of ribonucleotide reductase the rate limiting enzyme activity in DNA synthesis. Furthermore, in agreement with these enzyme studies, DNA synthesis in a hydroxyurea resistant cell line with high levels of ribonucleotide reductase activity showed increased resistance to gossypol when compared to wild type cells with normal levels of reductase activity. Ribonucleotide reductase is the first specific site of action documented for gossypol which can explain its recently described antiproliferative, cell cycle and toxic effects.

Involvement of ribonucleotide reductase in cellular differentiation.

L6 and L8 rat myoblast cell lines have been selected for resistance to hydroxyurea, an antineoplastic agent whose intracellular target is the rate-limiting enzyme activity of DNA synthesis, ribonucleotide reductase. In contrast to the differentiation-competent parental lines from which they were selected, the drug-resistant lines exhibit a grossly altered or absent myogenic capacity. Independent selections have revealed a strong correlation between changes in ribonucleotide reductase, as determined by velocity levels and product pool analyses, and altered myogenic potential. These results provide the first indication that alterations in this key enzyme activity and its accompanying deoxyribonucleoside triphosphate pools can affect cellular differentiation.

Training vocational rehabilitation counselors who work with chronic mental patients.

Because of the inefficacy of disparate psychiatric and rehabilitative approaches to psychosocial restoration of chronic mental patients, the authors designed the New England Psychiatric Rehabilitation Training Program for vocational rehabilitation counselors who work with these patients. The program extends Erikson's epigenetic sequence to development of work capacity and emphasizes a comprehensive, multiaxial approach to psychopathology and vocational rehabilitation. After 6 weeks of seminars, clinical work, and supervision, counselors return to their agencies and receive an additional 8 weeks of part-time support from field faculty instructors.

Hypomania and mania after withdrawal of tricyclic antidepressants.

Seven patients who had been maintained on tricyclic antidepressants developed signs of hypomania or mania shortly (two-seven days) after drug withdrawal. Three patients responded promptly to treatment with neuroleptics. One patient receiving lithium and three others who received no further drug treatment experienced more gradual resolution of symptoms. Tricyclic withdrawal is accompanied by changes in the turnover rate of individual neurotransmitters as well as by shifts in the equilibrium between various transmitter systems. These events may be accompanied by alterations in mood. Although relapse to depression is more common, hypomania or mania may also occur.